Ultra-high Efficiency DC-DC Converter using GaN Devices

DEFF Research Database (Denmark)

Ramachandran, Rakesh

2016-01-01

properties of GaN devices can be utilized in power converters to make them more compact and highly efficient. This thesis entitled “Ultra-high Efficiency DC-DC Converter using GaN devices” focuses on achieving ultra-high conversion efficiency in an isolated dc-dc converter by the optimal utilization of Ga...... for many decades. However, the rate of improvement slowed as the silicon power materials asymptotically approached its theoretical bounds. Compared to Si, wideband gap materials such as Silicon Carbide (SiC) and Gallium Nitride (GaN) are promising semiconductors for power devices due to their superior...... in this thesis. Efficiency measurements from the hardware prototype of both the topologies are also presented in this thesis. Finally, the bidirectional operation of an optimized isolated dc-dc converter is presented. The optimized converter has achieved an ultra-high efficiency of 98.8% in both directions...

Improved color purity and efficiency by a coguest emitter system in doped red light-emitting devices

Energy Technology Data Exchange (ETDEWEB)

Chen Jiangshan [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of Chinese Academy of Sciences, Changchun 130022 (China); Ma Dongge [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of Chinese Academy of Sciences, Changchun 130022 (China)]. E-mail: mdg1014@ciac.jl.cn

2007-01-15

We demonstrate red organic light-emitting diodes (OLEDs) with improved color purity and electroluminescence (EL) efficiency by codoping a green fluorescent sensitizer 10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5H,11H -(1)-benzopyropyrano(6,7-8-i,j)quinolizin-11-one (C545T) as the second dopant and a red fluorescent dye 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran (DCJTB) as the lumophore into tris(8-hydroquinoline) aluminum (Alq{sub 3}) host. It was found that the C545T dopant did not by itself emit but assisted the carrier trapping from the host Alq{sub 3} to the red emitting dopant. The red OLEDs realized by this approach not only kept the purity of the emission color, but also significantly improved the EL efficiency. The current efficiency and power efficiency, respectively, reached 12cd/A at a current density of 0.3mA/cm{sup 2} and 10lm/W at a current density of 0.02mA/cm{sup 2}, which are enhanced by 1.4 and 2.6 times compared with devices where the emissive layer is composed of the DCJTB doped Alq{sub 3}, and a stable red emission (chromaticity coordinates: x=0.64, y=0.36) was obtained in a wide range of voltage. Our results indicate that the coguest system is a promising method for obtaining high-efficiency red OLEDs.

Improving Perovskite Solar Cells: Insights From a Validated Device Model

NARCIS (Netherlands)

Sherkar, Tejas S.; Momblona, Cristina; Gil-Escrig, Lidon; Bolink, Henk J.; Koster, L. Jan Anton

2017-01-01

To improve the efficiency of existing perovskite solar cells (PSCs), a detailed understanding of the underlying device physics during their operation is essential. Here, a device model has been developed and validated that describes the operation of PSCs and quantitatively explains the role of

Design of sample analysis device for iodine adsorption efficiency test in NPPs

International Nuclear Information System (INIS)

Ji Jinnan

2015-01-01

In nuclear power plants, iodine adsorption efficiency test is used to check the iodine adsorption efficiency of the iodine adsorber. The iodine adsorption efficiency can be calculated through the analysis of the test sample, and thus to determine if the performance of the adsorber meets the requirement on the equipment operation and emission. Considering the process of test and actual demand, in this paper, a special device for the analysis of this kind of test sample is designed. The application shows that the device is with convenient operation and high reliability and accurate calculation, and improves the experiment efficiency and reduces the experiment risk. (author)

Improving Light Outcoupling Efficiency for OLEDs with Microlens Array Fabricated on Transparent Substrate

Directory of Open Access Journals (Sweden)

Jun Wang

2014-01-01

Full Text Available Low light outcoupling efficiency restricts the wide application of organic light-emitting diodes in solid state light market although the internal quantum efficiency of the device could reach near to 100%. In order to improve the output efficiency, different kinds of microlens array on the substrate emission surface were designed and simulated using light tracing method. Simulation results indicate that the microlens array on the substrate could efficiently improve the light output efficiency and an enhancement of 1.8 could be obtained with optimized microlens structure design. The microlens array with semicircle shape using polymer material was fabricated on glass substrate by a facile approach. Finally, the organic device with microlens array substrate was manufactured and the light output of the device with surface microlens structure could increase to 1.64 times comparing with the device without microlens.

Enhanced pathway efficiency of Saccharomyces cerevisiae by introducing thermo-tolerant devices.

Science.gov (United States)

Liu, Yueqin; Zhang, Genli; Sun, Huan; Sun, Xiangying; Jiang, Nisi; Rasool, Aamir; Lin, Zhanglin; Li, Chun

2014-10-01

In this study, thermo-tolerant devices consisting of heat shock genes from thermophiles were designed and introduced into Saccharomyces cerevisiae for improving its thermo-tolerance. Among ten engineered thermo-tolerant yeasts, T.te-TTE2469, T.te-GroS2 and T.te-IbpA displayed over 25% increased cell density and 1.5-4-fold cell viability compared with the control. Physiological characteristics of thermo-tolerant strains revealed that better cell wall integrity, higher trehalose content and enhanced metabolic energy were preserved by thermo-tolerant devices. Engineered thermo-tolerant strain was used to investigate the impact of thermo-tolerant device on pathway efficiency by introducing β-amyrin synthesis pathway, showed 28.1% increased β-amyrin titer, 28-35°C broadened growth temperature range and 72h shortened fermentation period. The results indicated that implanting heat shock proteins from thermophiles to S. cerevisiae would be an efficient approach to improve its thermo-tolerance. Copyright © 2014 Elsevier Ltd. All rights reserved.

Electromagnetic Radiation Efficiency of Body-Implanted Devices

Science.gov (United States)

Nikolayev, Denys; Zhadobov, Maxim; Karban, Pavel; Sauleau, Ronan

2018-02-01

Autonomous wireless body-implanted devices for biotelemetry, telemedicine, and neural interfacing constitute an emerging technology providing powerful capabilities for medicine and clinical research. We study the through-tissue electromagnetic propagation mechanisms, derive the optimal frequency range, and obtain the maximum achievable efficiency for radiative energy transfer from inside a body to free space. We analyze how polarization affects the efficiency by exciting TM and TE modes using a magnetic dipole and a magnetic current source, respectively. Four problem formulations are considered with increasing complexity and realism of anatomy. The results indicate that the optimal operating frequency f for deep implantation (with a depth d ≳3 cm ) lies in the (108- 109 )-Hz range and can be approximated as f =2.2 ×107/d . For a subcutaneous case (d ≲3 cm ), the surface-wave-induced interference is significant: within the range of peak radiation efficiency (about 2 ×108 to 3 ×109 Hz ), the max-to-min ratio can reach a value of 6.5. For the studied frequency range, 80%-99% of radiation efficiency is lost due to the tissue-air wave-impedance mismatch. Parallel polarization reduces the losses by a few percent; this effect is inversely proportional to the frequency and depth. Considering the implantation depth, the operating frequency, the polarization, and the directivity, we show that about an order-of-magnitude efficiency improvement is achievable compared to existing devices.

Improving plasmonic waveguides coupling efficiency using nanoantennas

DEFF Research Database (Denmark)

Andryieuski, Andrei; Malureanu, Radu; Bouillard, Jean-Sebastien

2012-01-01

. The classical dipole antenna scheme can be improved by changing the nanoantenna geometry, adding constructive elements such as reflecting bars and mirrors and using arrays of antennas. The modelling designates that the coupling efficiency from a vertical fiber to a plasmonic waveguide can be improved more than......Plasmonic waveguides bear a lot of potential for photonic applications. However, one of the challenges for implementing them in devices is the low coupling efficiency to and from optical fibers. We report on our approach to facilitate the coupling efficiency with the use of metallic nanoantennas...... in 180 times in comparison with a direct fiber-waveguide coupling. Pros and cons of each configuration are discussed. Fabrication and characterisation results are reported....

Magnetism reflectometer study shows LiF layers improve efficiency in spin valve devices

Energy Technology Data Exchange (ETDEWEB)

Bardoel, Agatha A [ORNL; Lauter, Valeria [ORNL; Szulczewski, Greg J [ORNL

2012-01-01

New, more efficient materials for spin valves - a device used in magnetic sensors, random access memories, and hard disk drives - may be on the way based on research using the magnetism reflectometer at Oak Ridge National Laboratory (ORNL). Spin valve devices work by means of two or more conducting magnetic material layers that alternate their electrical resistance depending on the layers alignment. Giant magnetoresistance is a quantum mechanical effect first observed in thin film structures about 20 years ago. The effect is observed as a significant change in electrical resistance, depending on whether the magnetization of adjacent ferromagnetic layers is in a parallel or an antiparallel magnetic alignment. 'What we are doing here is developing new materials. The search for new materials suitable for injecting and transferring carriers with a preferential spin orientation is most important for the development of spintronics,' said Valeria Lauter, lead instrument scientist on the magnetism reflectometer at the Spallation Neutron Source (SNS), who collaborated on the experiment. The researchers discovered that the conductivity of such materials is improved when an organic polymer semiconductor layer is placed between the magnetic materials. Organic semiconductors are now the material of choice for future spin valve devices because they preserve spin coherence over longer times and distances than conventional semiconductors. While research into spin valves has been ongoing, research into organic semiconductors is recent. Previous research has shown that a 'conductivity mismatch' exists in spin valve systems in which ferromagnetic metal electrodes interface with such organic semiconductors as Alq3 ({pi}-conjugated molecule tris(8-hydroxy-quinoline) aluminium). This mismatch limits the efficient injection of the electrons from the electrodes at the interface with the semiconductor material. However, lithium fluoride (LiF), commonly used in light

Improving the Efficiency of Solid State Light Sources

International Nuclear Information System (INIS)

Joanna McKittrick

2003-01-01

This proposal addresses the national need to develop a high efficiency light source for general illumination applications. The goal is to perform research that would lead to the fabrication of a unique solid state, white-emitting light source. This source is based on an InGaN/GaN UV-emitting chip that activates a luminescent material (phosphor) to produce white light. White-light LEDs are commercially available which use UV from a GaN chip to excite a phosphor suspended in epoxy around the chip. Currently, these devices are relatively inefficient. This research will target one technical barrier that presently limits the efficiency of GaN based devices. Improvements in efficiencies will be achieved by improving the internal conversion efficiency of the LED die, by improving the coupling between the die and phosphor(s) to reduce losses at the surfaces, and by selecting phosphors to maximize the emissions from the LEDs in conversion to white light. The UCSD research team proposes for this project to develop new phosphors that have high quantum efficiencies that can be activated by the UV-blue (360-410 nm) light emitted by the GaN device. The main goal for the UCSD team was to develop new phosphor materials with a very specific property: phosphors that could be excited at long UV-wavelengths (λ=350-410 nm). The photoluminescence of these new phosphors must be activated with photons emitted from GaN based dies. The GaN diodes can be designed to emit UV-light in the same range (λ=350-410 nm). A second objective, which is also very important, is to search for alternate methods to fabricate these phosphors with special emphasis in saving energy and time and reduce pollution

A novel electroluminescent PPV copolymer and silsesquioxane nanocomposite film for the preparation of efficient PLED devices.

Science.gov (United States)

Venegoni, Ivan; Carniato, Fabio; Olivero, Francesco; Bisio, Chiara; Pira, Nello Li; Lambertini, Vito Guido; Marchese, Leonardo

2012-11-02

Polymer light-emitting diodes (PLEDs) have attracted growing interest in recent years for their potential use in displays and lighting fields. Nevertheless, PLED devices have some disadvantages in terms of low optoelectronic efficiency, high cost, short lifetimes and low thermal stability, which limit their final applications. Huge efforts have been made recently to improve the performances of these devices. The addition of inorganic or hybrid organic-inorganic nanoparticles to the light-emitting polymers, for example, allows their thermal stability and electroluminescent efficiency to be increased. Following this approach, novel PLED devices based on composite films of PPV-derivative copolymer (commercial name Super Yellow, SY) and octaisobutil POSS, were developed in this study. The device containing Super Yellow loaded with 1 wt% of POSS showed higher efficiency (ca. +30%) and improved lifetime in comparison to PLED prepared with the pure electroluminescent polymer. The PLED devices developed in this study are suitable candidates for automotive dashboards and, in general, for lighting applications.

Optoelectronic devices, low temperature preparation methods, and improved electron transport layers

KAUST Repository

Eita, Mohamed S.

2016-08-04

An optoelectronic device such as a photovoltaic device which has at least one layer, such as an electron transport layer, which comprises a plurality of alternating, oppositely charged layers including metal oxide layers. The metal oxide can be zinc oxide. The plurality of layers can be prepared by layer-by-layer processing in which alternating layers are built up step-by-step due to electrostatic attraction. The efficiency of the device can be increased by this processing method compared to a comparable method like sputtering. The number of layers can be controlled to improve device efficiency. Aqueous solutions can be used which is environmentally friendly. Annealing can be avoided. A quantum dot layer can be used next to the metal oxide layer to form a quantum dot heterojunction solar device.

Efficiency improvements of offline metrology job creation

Science.gov (United States)

Zuniga, Victor J.; Carlson, Alan; Podlesny, John C.; Knutrud, Paul C.

1999-06-01

Progress of the first lot of a new design through the production line is watched very closely. All performance metrics, cycle-time, in-line measurement results and final electrical performance are critical. Rapid movement of this lot through the line has serious time-to-market implications. Having this material waiting at a metrology operation for an engineer to create a measurement job plan wastes valuable turnaround time. Further, efficient use of a metrology system is compromised by the time required to create and maintain these measurement job plans. Thus, having a method to develop metrology job plans prior to the actual running of the material through the manufacture area can significantly improve both cycle time and overall equipment efficiency. Motorola and Schlumberger have worked together to develop and test such a system. The Remote Job Generator (RJG) created job plans for new device sin a manufacturing process from an NT host or workstation, offline. This increases available system tim effort making production measurements, decreases turnaround time on job plan creation and editing, and improves consistency across job plans. Most importantly this allows job plans for new devices to be available before the first wafers of the device arrive at the tool for measurement. The software also includes a database manager which allows updates of existing job plans to incorporate measurement changes required by process changes or measurement optimization. This paper will review the result of productivity enhancements through the increased metrology utilization and decreased cycle time associated with the use of RJG. Finally, improvements in process control through better control of Job Plans across different devices and layers will be discussed.

Investigation of Processing, Microstructures and Efficiencies of Polycrystalline CdTe Photovoltaic Films and Devices

Science.gov (United States)

Munshi, Amit Harenkumar

with processes suitable for mass production. These are the highest efficiencies reported by any university or national laboratory for polycrystalline thin-film CdTe photovoltaics bettered only by researchers at First Solar Inc. Processing experiments are traditionally designed based on simulation results however in these study microscopic materials characterization has been used as the primary driving force to understand the effects of processing conditions. Every structure and efficiency reported in this study has been extensively studied using microscopic imaging and materials characterization and processing conditions accordingly altered to achieve higher efficiencies. Understanding CdCl2 passivation treatment out of this has been critical to this process. Several observations with regard to effect of CdCl 2 passivation have allowed the use to this treatment to achieve optimum performance. The effects of deposition temperature are also studied in rigorous details. All of these studies have played an important role in optimization of process that lead to high efficiency thin-film CdTe photovoltaic devices. An effort is made in this study to better understand and establish a 3-way relationship between processing conditions, film microstructure and device efficiency for sublimated thin-film CdTe photovoltaics. Some crucial findings include impact of grain size on efficiency of photovoltaic devices and improvement in fill-factor resulting from use of thicker CdTe absorber with larger grain size. An attempt is also made to understand the microstructure as the device efficiency improves from 1% efficiency to over 18% efficiency.

Progress in high-efficient solution process organic photovoltaic devices fundamentals, materials, devices and fabrication

CERN Document Server

Li, Gang

2015-01-01

This book presents an important technique to process organic photovoltaic devices. The basics, materials aspects and manufacturing of photovoltaic devices with solution processing are explained. Solution processable organic solar cells - polymer or solution processable small molecules - have the potential to significantly reduce the costs for solar electricity and energy payback time due to the low material costs for the cells, low cost and fast fabrication processes (ambient, roll-to-roll), high material utilization etc. In addition, organic photovoltaics (OPV) also provides attractive properties like flexibility, colorful displays and transparency which could open new market opportunities. The material and device innovations lead to improved efficiency by 8% for organic photovoltaic solar cells, compared to 4% in 2005. Both academic and industry research have significant interest in the development of this technology. This book gives an overview of the booming technology, focusing on the solution process fo...

Enhancement of efficiencies for tandem green phosphorescent organic light-emitting devices with a p-type charge generation layer

Energy Technology Data Exchange (ETDEWEB)

Yoo, Byung Soo; Jeon, Young Pyo; Lee, Dae Uk; Kim, Tae Whan, E-mail: twk@hanayng.ac.kr

2014-10-15

The operating voltage of the tandem green phosphorescent organic light-emitting device with a 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile layer was improved by 3% over that of the organic light-emitting device with a molybdenum trioxide layer. The maximum brightness of the tandem green phosphorescent organic light-emitting device at 21.9 V was 26,540 cd/m{sup 2}. The dominant peak of the electroluminescence spectra for the devices was related to the fac-tris(2-phenylpyridine) iridium emission. - Highlights: • Tandem OLEDs with CGL were fabricated to enhance their efficiency. • The operating voltage of the tandem OLED with a HAT-CN layer was improved by 3%. • The efficiency and brightness of the tandem OLED were 13.9 cd/A and 26,540 cd/m{sup 2}. • Efficiency of the OLED with a HAT-CN layer was lower than that with a MoO{sub 3} layer. - Abstract: Tandem green phosphorescent organic light-emitting devices with a 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile or a molybdenum trioxide charge generation layer were fabricated to enhance their efficiency. Current density–voltage curves showed that the operating voltage of the tandem green phosphorescent organic light-emitting device with a 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile layer was improved by 3% over that of the corresponding organic light-emitting device with a molybdenum trioxide layer. The efficiency and the brightness of the tandem green phosphorescent organic light-emitting device were 13.9 cd/A and 26,540 cd/m{sup 2}, respectively. The current efficiency of the tandem green phosphorescent organic light-emitting device with a 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile layer was lower by 1.1 times compared to that of the corresponding organic light-emitting device with molybdenum trioxide layer due to the decreased charge generation and transport in the 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile layer resulting from triplet–triplet exciton annihilation.

Computer model of copper resistivity will improve the efficiency of field-compression devices

International Nuclear Information System (INIS)

Burgess, T.J.

1977-01-01

By detonating a ring of high explosive around an existing magnetic field, we can, under certain conditions, compress the field and multiply its strength tremendously. In this way, we can duplicate for a fraction of a second the extreme pressures that normally exist only in the interior of stars and planets. Under such pressures, materials may exhibit behavior that will confirm or alter current notions about the fundamental structure of matter and the ongoing processes in planetary interiors. However, we cannot design an efficient field-compression device unless we can calculate the electrical resistivity of certain basic metal components, which interact with the field. To aid in the design effort, we have developed a computer code that calculates the resistivity of copper and other metals over the wide range of temperatures and pressures found in a field-compression device

Efficient organic light-emitting devices with platinum-complex emissive layer

KAUST Repository

Yang, Xiaohui

2011-01-18

We report efficient organic light-emitting devices having a platinum-complex emissive layer with the peak external quantum efficiency of 17.5% and power efficiency of 45 lm W−1. Variation in the device performance with platinum-complex layer thickness can be attributed to the interplay between carrier recombination and intermolecular interactions in the layer. Efficient white devices using double platinum-complex layers show the external quantum efficiency of 10%, the Commission Internationale d’Énclairage coordinates of (0.42, 0.41), and color rendering index of 84 at 1000 cd m−2.

Efficient organic light-emitting devices with platinum-complex emissive layer

KAUST Repository

Yang, Xiaohui; Wu, Fang-Iy; Haverinen, Hanna; Li, Jian; Cheng, Chien-Hong; Jabbour, Ghassan E.

2011-01-01

We report efficient organic light-emitting devices having a platinum-complex emissive layer with the peak external quantum efficiency of 17.5% and power efficiency of 45 lm W−1. Variation in the device performance with platinum-complex layer thickness can be attributed to the interplay between carrier recombination and intermolecular interactions in the layer. Efficient white devices using double platinum-complex layers show the external quantum efficiency of 10%, the Commission Internationale d’Énclairage coordinates of (0.42, 0.41), and color rendering index of 84 at 1000 cd m−2.

Factors limiting device efficiency in organic photovoltaics

NARCIS (Netherlands)

Janssen, R.A.J.; Nelson, J.

2013-01-01

The power conversion efficiency of the most efficient organic photovoltaic (OPV) cells has recently increased to over 10%. To enable further increases, the factors limiting the device efficiency in OPV must be identified. In this review, the operational mechanism of OPV cells is explained and the

Efficient blue-green and green electroluminescent devices obtained by doping iridium complexes into hole-block material as supplementary light-emitting layer

Energy Technology Data Exchange (ETDEWEB)

Zhou, Liang [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zheng, Youxuan, E-mail: yxzheng@mail.nju.edu.cn [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Deng, Ruiping; Feng, Jing; Song, Mingxing; Hao, Zhaomin [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zhang, Hongjie, E-mail: hongjie@ciac.jl.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zuo, Jinglin; You, Xiaozeng [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

2014-04-15

In this work, organic electroluminescent (EL) devices with dominant and supplementary light-emitting layers (EMLs) were designed to further improve the EL performances of two iridium{sup III}-based phosphorescent complexes, which have been reported to provide EL devices with slow EL efficiency roll-off. The widely used hole-block material 2,2′,2''-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) was selected as host material to construct the supplementary EML. Compared with single-EML devices, double-EMLs devices showed higher EL efficiencies, higher brightness, and lower operation voltage attributed to wider recombination zone and better balance of carriers. In addition, the insertion of supplementary EML is instrumental in facilitating carriers trapping, thus improving the color purity. Finally, high performance blue-green and green EL devices with maximum current efficiencies of 35.22 and 90.68 cd/A, maximum power efficiencies of 26.36 and 98.18 lm/W, and maximum brightness of 56,678 and 112,352 cd/m{sup 2}, respectively, were obtained by optimizing the doping concentrations. Such a device design strategy extends the application of a double EML device structure and provides a chance to simplify device fabrication processes. -- Highlights: • Electroluminescent devices with supplementary light-emitting layer were fabricated. • Doping concentrations and thicknesses were optimized. • Better balance of holes and electrons causes the enhanced efficiency. • Improved carrier trapping suppresses the emission of host material.

High efficiency rubrene based inverted top-emission organic light emitting devices with a mixed single layer

International Nuclear Information System (INIS)

Wang, Zhaokui; Lou, Yanhui; Naka, Shigeki; Okada, Hiroyuki

2010-01-01

Inverted top-emission organic light emitting devices (TEOLEDs) with a mixed single layer by mixing of electron transport materials (PyPySPyPy and Alq 3 ), hole transport material (α-NPD) and dope material (rubrene) were investigated. Maximum power efficiency of 3.5 lm/W and maximum luminance of 7000 cd/m 2 were obtained by optimizing the mixing ratio of PyPySPyPy:Alq 3 :α-NPD:rubrene=25:50:25:1. Luminance and power efficiency of mixed single layer device were two times improved compared to bi-layer heterojunction device and tri-layer heterojunction device. Lifetime test also shows that the mixed single layer device exhibits longer operational lifetimes of 343 h, which is three times longer than the 109 h for tri-layer device, and two times longer than the 158 h for bi-layer device. In addition, the maximum luminance and power efficiency were obtained at 20,000 cd/m 2 and 7.5 lm/W, respectively, when a TPD layer of 45 nm was capped onto the top metal electrode.

Improved efficiency of organic light-emitting diodes based on a europium complex by fluorescent dye

Energy Technology Data Exchange (ETDEWEB)

You Han [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of Chinese Academy of Sciences, Changchun 130022 (China); Fang Junfeng [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of Chinese Academy of Sciences, Changchun 130022 (China); Gao Jia [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of Chinese Academy of Sciences, Changchun 130022 (China); Ma Dongge [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of Chinese Academy of Sciences, Changchun 130022 (China)]. E-mail: mdg1014@ciac.jl.cn

2007-01-15

Improved efficiency of organic light-emitting diodes (OLEDs) based on europium complexes have been realized by using a fluorescent dye 4-(dicyanomethylene)-2-t-butyl-6 (1,1,7,7-tetramethyljulolidyl-9-enyl))-4H-pyran (DCJTB) doping .The luminous efficiency of the devices with a fluorescent dye in the emissive layer was found to improve two times of that in devices without fluorescent dye. The devices showed pure red light, which is the characteristic emission of trivalent europium ion with a full-width at half-maximum of 3 nm.The maximum brightness and luminous efficiency reached 1200 cd/m{sup 2} at 23 V and 7.3 cd/A (2.0 lm/w), respectively, at a current density of 0.35 mA/cm{sup 2}.

Energy efficient hybrid computing systems using spin devices

Science.gov (United States)

Sharad, Mrigank

Emerging spin-devices like magnetic tunnel junctions (MTJ's), spin-valves and domain wall magnets (DWM) have opened new avenues for spin-based logic design. This work explored potential computing applications which can exploit such devices for higher energy-efficiency and performance. The proposed applications involve hybrid design schemes, where charge-based devices supplement the spin-devices, to gain large benefits at the system level. As an example, lateral spin valves (LSV) involve switching of nanomagnets using spin-polarized current injection through a metallic channel such as Cu. Such spin-torque based devices possess several interesting properties that can be exploited for ultra-low power computation. Analog characteristic of spin current facilitate non-Boolean computation like majority evaluation that can be used to model a neuron. The magneto-metallic neurons can operate at ultra-low terminal voltage of ˜20mV, thereby resulting in small computation power. Moreover, since nano-magnets inherently act as memory elements, these devices can facilitate integration of logic and memory in interesting ways. The spin based neurons can be integrated with CMOS and other emerging devices leading to different classes of neuromorphic/non-Von-Neumann architectures. The spin-based designs involve `mixed-mode' processing and hence can provide very compact and ultra-low energy solutions for complex computation blocks, both digital as well as analog. Such low-power, hybrid designs can be suitable for various data processing applications like cognitive computing, associative memory, and currentmode on-chip global interconnects. Simulation results for these applications based on device-circuit co-simulation framework predict more than ˜100x improvement in computation energy as compared to state of the art CMOS design, for optimal spin-device parameters.

Theoretical study on device efficiency of pulsed liquid jet pump

International Nuclear Information System (INIS)

Gao Chuanchang; Lu Hongqi; Wang Shicheng; Cheng Mingchuan

2001-01-01

The influence of the main factors on device efficiency of pulsed liquid jet pump with gas-liquid piston is analysed, the theoretical equation and its time-averaged solution of pulsed liquid jet pump device efficiency are derived. The theoretical and experimental results show that the efficiency of transmission of energy and mass to use pulsed jet is greatly raised, compared with steady jet, in the same device of liquid jet pump. The calculating results of time-averaged efficiency of pulsed liquid jet pump are approximately in agreement with the experimental results in our and foreign countries

Highly efficient hybrid energy generator: coupled organic photovoltaic device and randomly oriented electrospun poly(vinylidene fluoride) nanofiber.

Science.gov (United States)

Park, Boongik; Lee, Kihwan; Park, Jongjin; Kim, Jongmin; Kim, Ohyun

2013-03-01

A hybrid architecture consisting of an inverted organic photovoltaic device and a randomly-oriented electrospun PVDF piezoelectric device was fabricated as a highly-efficient energy generator. It uses the inverted photovoltaic device with coupled electrospun PVDF nanofibers as tandem structure to convert solar and mechanical vibrations energy to electricity simultaneously or individually. The power conversion efficiency of the photovoltaic device was also significantly improved up to 4.72% by optimized processes such as intrinsic ZnO, MoO3 and active layer. A simple electrospinning method with the two electrode technique was adopted to achieve a high voltage of - 300 mV in PVDF piezoelectric fibers. Highly-efficient HEG using voltage adder circuit provides the conceptual possibility of realizing multi-functional energy generator whenever and wherever various energy sources are available.

Improving quantum efficiency and spectral resolution of a CCD through direct manipulation of the depletion region

Science.gov (United States)

Brown, Craig; Ambrosi, Richard M.; Abbey, Tony; Godet, Olivier; O'Brien, R.; Turner, M. J. L.; Holland, Andrew; Pool, Peter J.; Burt, David; Vernon, David

2008-07-01

Future generations of X-ray astronomy instruments will require position sensitive detectors in the form of charge-coupled devices (CCDs) for X-ray spectroscopy and imaging with the ability to probe the X-ray universe with greater efficiency. This will require the development of CCDs with structures that will improve their quantum efficiency over the current state of the art. The quantum efficiency improvements would have to span a broad energy range (0.2 keV to >15 keV). These devices will also have to be designed to withstand the harsh radiation environments associated with orbits that extend beyond the Earth's magnetosphere. This study outlines the most recent work carried out at the University of Leicester focused on improving the quantum efficiency of an X-ray sensitive CCD through direct manipulation of the device depletion region. It is also shown that increased spectral resolution is achieved using this method due to a decrease in the number of multi-pixel events. A Monte Carlo and analytical models of the CCD have been developed and used to determine the depletion depths achieved through variation of the device substrate voltage, Vss. The models are also used to investigate multi-pixel event distributions and quantum efficiency as a function of depletion depth.

Energy-Efficient Resource and Power Allocation for Underlay Multicast Device-to-Device Transmission

Directory of Open Access Journals (Sweden)

Fan Jiang

2017-11-01

Full Text Available In this paper, we present an energy-efficient resource allocation and power control scheme for D2D (Device-to-Device multicasting transmission. The objective is to maximize the overall energy-efficiency of D2D multicast clusters through effective resource allocation and power control schemes, while considering the quality of service (QoS requirements of both cellular users (CUs and D2D clusters. We first build the optimization model and a heuristic resource and power allocation algorithm is then proposed to solve the energy-efficiency problem with less computational complexity. Numerical results indicate that the proposed algorithm outperforms existing schemes in terms of throughput per energy consumption.

Making Image More Energy Efficient for OLED Smart Devices

Directory of Open Access Journals (Sweden)

Deguang Li

2016-01-01

Full Text Available Now, more and more mobile smart devices are emerging massively; energy consumption of these devices has become an important consideration due to the limitation of battery capacity. Displays are the dominant energy consuming component of battery-operated devices, giving rise to organic light-emitting diode (OLED as a new promising display technology, which consumes different power when displaying different content due to their emissive nature. Based on this property, we propose an approach to improve image energy efficiency on OLED displays by perceiving image content. The key idea of our approach is to eliminate undesired details while preserving the region of interest of the image by leveraging the color and spatial information. First, we use edge detection algorithm to extract region of interest (ROI of an image. Next, we gradually change luminance and saturation of region of noninterest (NON-ROI of the image. Then we perform detailed experiment and case study to validate our approach; experiment results show that our approach can save 22.5% energy on average while preserving high quality of the image.

Efficiency improvement of flexible fluorescent and phosphorescent organic light emitting diodes by inserting a spin-coating buffer layer

International Nuclear Information System (INIS)

Tsai, Yu-Sheng; Wang, Shun-Hsi; Chen, Shen-Yaur; Su, Shin-Yuan; Juang, Fuh-Shyang

2009-01-01

We dissolved hole transport materials α-NPD and NPB in THF solvent, and spin-coated the α-NPD + THF or NPB + THF solution onto ITO anode surface to improve the luminance efficiency and lifetime of flexible fluorescent and phosphorescent organic light emitting diodes. Then the BCP and TPBi were employed as hole blocking layer (HBL) of phosphorescent device and its thickness was optimized. From the experimental results, the maximum luminance efficiency is 4.4 cd/A at 9 V of fluorescent device and 24.4 cd/A of phosphorescent device, respectively. Such an improvement in the device performance was attributed to the smoother surface and good contact between the interface of spin-coated HTL/ITO, the hole were effectively injected from the anode into the organic layer. And the deposited HTL can block excitons from diffusing into the anode to quench, thus improving the luminance efficiency and lifetime greatly.

Improvement of wireless power transmission efficiency of implantable subcutaneous devices by closed magnetic circuit mechanism.

Science.gov (United States)

Jo, Sung-Eun; Joung, Sanghoon; Suh, Jun-Kyo Francis; Kim, Yong-Jun

2012-09-01

Induction coils were fabricated based on flexible printed circuit board for inductive transcutaneous power transmission. The coil had closed magnetic circuit (CMC) structure consisting of inner and outer magnetic core. The power transmission efficiency of the fabricated device was measured in the air and in vivo condition. It was confirmed that the CMC coil had higher transmission efficiency than typical air-core coil. The power transmission efficiency during a misalignment between primary coil and implanted secondary coil was also evaluated. The decrease of mutual inductance between the two coils caused by the misalignment led to a low efficiency of the inductive link. Therefore, it is important to properly align the primary coil and implanted secondary coil for effective power transmission. To align the coils, a feedback coil was proposed. This was integrated on the backside of the primary coil and enabled the detection of a misalignment of the primary and secondary coils. As a result of using the feedback coil, the primary and secondary coils could be aligned without knowledge of the position of the implanted secondary coil.

Efficient light emitting devices based on phosphorescent partially doped emissive layers

KAUST Repository

Yang, Xiaohui

2013-05-29

We report efficient organic light emitting devices employing an ultrathin phosphor emissive layer. The electroluminescent spectra of these devices can be tuned by introducing a low-energy emitting phosphor layer into the emission zone. Devices with the emissive layer consisting of multiple platinum-complex/spacer layer cells show a peak external quantum efficiency of 18.1%, which is among the best EQE values for platinum-complex based light emitting devices. Devices with an ultrathin phosphor emissive layer show stronger luminance decay with the operating time compared to the counterpart devices having a host-guest emissive layer.

A Pareto-based multi-objective optimization algorithm to design energy-efficient shading devices

International Nuclear Information System (INIS)

Khoroshiltseva, Marina; Slanzi, Debora; Poli, Irene

2016-01-01

Highlights: • We present a multi-objective optimization algorithm for shading design. • We combine Harmony search and Pareto-based procedures. • Thermal and daylighting performances of external shading were considered. • We applied the optimization process to a residential social housing in Madrid. - Abstract: In this paper we address the problem of designing new energy-efficient static daylight devices that will surround the external windows of a residential building in Madrid. Shading devices can in fact largely influence solar gains in a building and improve thermal and lighting comforts by selectively intercepting the solar radiation and by reducing the undesirable glare. A proper shading device can therefore significantly increase the thermal performance of a building by reducing its energy demand in different climate conditions. In order to identify the set of optimal shading devices that allow a low energy consumption of the dwelling while maintaining high levels of thermal and lighting comfort for the inhabitants we derive a multi-objective optimization methodology based on Harmony Search and Pareto front approaches. The results show that the multi-objective approach here proposed is an effective procedure in designing energy efficient shading devices when a large set of conflicting objectives characterizes the performance of the proposed solutions.

Nanoscale Dimples for Improved Absorption in and Efficiency of Organic Solar Cells

DEFF Research Database (Denmark)

Goszczak, Arkadiusz Jaroslaw; Adam, Jost; Cielecki, Pawel Piotr

Organic solar cells (OSC’s) have attracted much attention in the past years due to their low costs, light weight and mechanical flexibility. A promising method for improving the power conversion efficiencies of the devices is by incorporating structured electrodes in the solar cell architecture....... That way light absorption in the active layers of the devices can be improved. A cheap and large-scale production compatible method for structuring the electrodes in OSC’s is by the use of Anodic Alumina Oxide (AAO) membranes. Here, nano-scale pores of controlled dimensions are formed through anodic...

Experimental evaluation of cooling efficiency of the high performance cooling device

Science.gov (United States)

Nemec, Patrik; Malcho, Milan

2016-06-01

This work deal with experimental evaluation of cooling efficiency of cooling device capable transfer high heat fluxes from electric elements to the surrounding. The work contain description of cooling device, working principle of cooling device, construction of cooling device. Experimental part describe the measuring method of device cooling efficiency evaluation. The work results are presented in graphic visualization of temperature dependence of the contact area surface between cooling device evaporator and electronic components on the loaded heat of electronic components in range from 250 to 740 W and temperature dependence of the loop thermosiphon condenser surface on the loaded heat of electronic components in range from 250 to 740 W.

Experimental evaluation of cooling efficiency of the high performance cooling device

Energy Technology Data Exchange (ETDEWEB)

Nemec, Patrik, E-mail: patrik.nemec@fstroj.uniza.sk; Malcho, Milan, E-mail: milan.malcho@fstroj.uniza.sk [University of Žilina, Faculty of Mechanical Engineering, Department of Power Engineering, Univerzitna 1, 010 26 Žilina (Slovakia)

2016-06-30

This work deal with experimental evaluation of cooling efficiency of cooling device capable transfer high heat fluxes from electric elements to the surrounding. The work contain description of cooling device, working principle of cooling device, construction of cooling device. Experimental part describe the measuring method of device cooling efficiency evaluation. The work results are presented in graphic visualization of temperature dependence of the contact area surface between cooling device evaporator and electronic components on the loaded heat of electronic components in range from 250 to 740 W and temperature dependence of the loop thermosiphon condenser surface on the loaded heat of electronic components in range from 250 to 740 W.

Device Strategies Directed to Improving the Efficiency of Solution-Processed Organic Solar Cells

KAUST Repository

Liang, Ru-Ze

2018-04-18

In the last decade, organic photovoltaics (OPVs) have been attracting much attention for their low cost, and feasibility of mass production in large-area modules. Reported power conversion efficiencies (PCE) of organic solar cells have reached more than 10%. These promising PCEs can be realized by uncovering important principles: (1) rational molecular design, (2) matching of the material energy level, (3) favorable morphology of donor-acceptor (D/A) network, (4) higher carrier mobilities, and (5) suppression of charge recombination within the bulk heterojunction (BHJ). Though these key properties are frequently stated, the relationships between these principles remain unclear, which motivates us to fill these gaps. In the beginning, we show that changing the sequence of donor and acceptor units of the benzodithiophene-core (BDT) SM donors critically impacts molecular packing and charge transport in BHJ solar cells. Moreover, we find out that by adding small amount of the external solvent additive, the domain size of the SMFQ1 become relatively smaller, resulting in the FF enhancement of ~70% and thus pushing PCE to >6.5%. To further improve the device performance, we utilize another technique of device optimization: Solvent Vapor Annealing (SVA). Compared with solvent additive, the SVA creates a solvent-saturated environment for SMs to re-arrange and crystalize, leading to PCE of >8%, with nearly-free bimolecular recombination. When the systems are shifted from fullerene acceptors to nonfullerene acceptors, using solvent additives in indacenodithiophene-core (IDT) systems significantly reduces the domain size from >500nm to <50nm and also allows the SM donors to orderly packed, rising the PCE from <1% to 4.5%. Furthermore in a similar IDT-based system, it shows unexpectedly high VOC and low energy loss, and high PCE > 6% can be reached by employing the dimethyl disulfide (DMDS) as the SVA solvent to re-organize the morphology from excessive mixing to ordered phase

Thermoelectric efficiency of nanoscale devices in the linear regime

Science.gov (United States)

Bevilacqua, G.; Grosso, G.; Menichetti, G.; Pastori Parravicini, G.

2016-12-01

We study quantum transport through two-terminal nanoscale devices in contact with two particle reservoirs at different temperatures and chemical potentials. We discuss the general expressions controlling the electric charge current, heat currents, and the efficiency of energy transmutation in steady conditions in the linear regime. With focus in the parameter domain where the electron system acts as a power generator, we elaborate workable expressions for optimal efficiency and thermoelectric parameters of nanoscale devices. The general concepts are set at work in the paradigmatic cases of Lorentzian resonances and antiresonances, and the encompassing Fano transmission function: the treatments are fully analytic, in terms of the trigamma functions and Bernoulli numbers. From the general curves here reported describing transport through the above model transmission functions, useful guidelines for optimal efficiency and thermopower can be inferred for engineering nanoscale devices in energy regions where they show similar transmission functions.

Highly Flexible and Efficient Solar Steam Generation Device.

Science.gov (United States)

Chen, Chaoji; Li, Yiju; Song, Jianwei; Yang, Zhi; Kuang, Yudi; Hitz, Emily; Jia, Chao; Gong, Amy; Jiang, Feng; Zhu, J Y; Yang, Bao; Xie, Jia; Hu, Liangbing

2017-08-01

Solar steam generation with subsequent steam recondensation has been regarded as one of the most promising techniques to utilize the abundant solar energy and sea water or other unpurified water through water purification, desalination, and distillation. Although tremendous efforts have been dedicated to developing high-efficiency solar steam generation devices, challenges remain in terms of the relatively low efficiency, complicated fabrications, high cost, and inability to scale up. Here, inspired by the water transpiration behavior of trees, the use of carbon nanotube (CNT)-modified flexible wood membrane (F-Wood/CNTs) is demonstrated as a flexible, portable, recyclable, and efficient solar steam generation device for low-cost and scalable solar steam generation applications. Benefitting from the unique structural merits of the F-Wood/CNTs membrane-a black CNT-coated hair-like surface with excellent light absorbability, wood matrix with low thermal conductivity, hierarchical micro- and nanochannels for water pumping and escaping, solar steam generation device based on the F-Wood/CNTs membrane demonstrates a high efficiency of 81% at 10 kW cm -2 , representing one of the highest values ever-reported. The nature-inspired design concept in this study is straightforward and easily scalable, representing one of the most promising solutions for renewable and portable solar energy generation and other related phase-change applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficiency optimization of green phosphorescent organic light-emitting device

Energy Technology Data Exchange (ETDEWEB)

Park, Jung Soo; Jeon, Woo Sik; Yu, Jae Hyung [Department of Information Display, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701 (Korea, Republic of); Pode, Ramchandra, E-mail: rbpode@khu.ac.k [Department of Physics, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701 (Korea, Republic of); Kwon, Jang Hyuk, E-mail: jhkwon@khu.ac.k [Department of Information Display, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701 (Korea, Republic of)

2011-03-01

Using a narrow band gap host of bis[2-(2-hydroxyphenyl)-pyridine]beryllium (Bepp{sub 2}) and green phosphorescent Ir(ppy){sub 3} [fac-tris(2-phenylpyridine) iridium III] guest concentration as low as 2%, high efficiency phosphorescent organic light-emitting diode (PHOLED) is realized. Current and power efficiencies of 62.5 cd/A (max.), 51.0 lm/W (max.), and external quantum efficiency (max.) of 19.8% are reported in this green PHOLED. A low current efficiency roll-off value of 10% over the brightness of 10,000 cd/m{sup 2} is noticed in this Bepp{sub 2} single host device. Such a high efficiency is obtained by the optimization of the doping concentration with the knowledge of the hole trapping and the emission zone situations in this host-guest system. It is suggested that the reported device performance is suitable for applications in high brightness displays and lighting.

Efficient generation of hepatic cells from mesenchymal stromal cells by an innovative bio-microfluidic cell culture device.

Science.gov (United States)

Yen, Meng-Hua; Wu, Yuan-Yi; Liu, Yi-Shiuan; Rimando, Marilyn; Ho, Jennifer Hui-Chun; Lee, Oscar Kuang-Sheng

2016-08-19

Mesenchymal stromal cells (MSCs) are multipotent and have great potential in cell therapy. Previously we reported the differentiation potential of human MSCs into hepatocytes in vitro and that these cells can rescue fulminant hepatic failure. However, the conventional static culture method neither maintains growth factors at an optimal level constantly nor removes cellular waste efficiently. In addition, not only is the duration of differentiating hepatocyte lineage cells from MSCs required to improve, but also the need for a large number of hepatocytes for cell therapy has not to date been addressed fully. The purpose of this study is to design and develop an innovative microfluidic device to overcome these shortcomings. We designed and fabricated a microfluidic device and a culture system for hepatic differentiation of MSCs using our protocol reported previously. The microfluidic device contains a large culture chamber with a stable uniform flow to allow homogeneous distribution and expansion as well as efficient induction of hepatic differentiation for MSCs. The device enables real-time observation under light microscopy and exhibits a better differentiation efficiency for MSCs compared with conventional static culture. MSCs grown in the microfluidic device showed a higher level of hepatocyte marker gene expression under hepatic induction. Functional analysis of hepatic differentiation demonstrated significantly higher urea production in the microfluidic device after 21 days of hepatic differentiation. The microfluidic device allows the generation of a large number of MSCs and induces hepatic differentiation of MSCs efficiently. The device can be adapted for scale-up production of hepatic cells from MSCs for cellular therapy.

Improved rectilinear scanning device for the whole body

International Nuclear Information System (INIS)

Berninger, W.H.

1975-01-01

A rectilinear scanning device for whole-body counting is described in which the spacial resolution is considerably improved upon by using photomultipliers with spherically curved photocathodes. By this measure, the distinct non-linearity between the output signals of the phototubes and the actual position of the scintillation in the scintillation crystal, as observed in plane photocathodes, is removed. The distances between the photomultipliers and the scintillation crystal can thus be kept very small whereby an improved statistic and lower noise can be obtained. Furthermore, thicker crystals can be used whereby the efficiency in the determination of higher energies is increased. The electronic signal processing to the reproduction of the nuclide distribution in the body is described in detail. (ORU/LH) [de

Highway-runoff quality, and treatment efficiencies of a hydrodynamic-settling device and a stormwater-filtration device in Milwaukee, Wisconsin

Science.gov (United States)

Horwatich, Judy A.; Bannerman, Roger T.; Pearson, Robert

2011-01-01

The treatment efficiencies of two prefabricated stormwater-treatment devices were tested at a freeway site in a high-density urban part of Milwaukee, Wisconsin. One treatment device is categorized as a hydrodynamic-settling device (HSD), which removes pollutants by sedimentation and flotation. The other treatment device is categorized as a stormwater-filtration device (SFD), which removes pollutants by filtration and sedimentation. During runoff events, flow measurements were recorded and water-quality samples were collected at the inlet and outlet of each device. Efficiency-ratio and summation-of-load (SOL) calculations were used to estimate the treatment efficiency of each device. Event-mean concentrations and loads that were decreased by passing through the HSD include total suspended solids (TSS), suspended sediment (SS), total phosphorus (TP), total copper (TCu), and total zinc (TZn). The efficiency ratios for these constituents were 42, 57, 17, 33, and 23 percent, respectively. The SOL removal rates for these constituents were 25, 49, 10, 27, and 16 percent, respectively. Event-mean concentrations and loads that increased by passing through the HSD include chloride (Cl), total dissolved solids (TDS), and dissolved zinc (DZn). The efficiency ratios for these constituents were -347, -177, and 20 percent, respectively. Four constituents—dissolved phosphorus (DP), chemical oxygen demand (COD), total polycyclic aromatic hydrocarbon (PAH), and dissolved copper (DCu)—are not included in the list of computed efficiency ratio and SOL because the variability between sampled inlet and outlet pairs were not significantly different. Event-mean concentrations and loads that decreased by passing through the SFD include TSS, SS, TP, DCu, TCu, DZn, TZn, and COD. The efficiency ratios for these constituents were 59, 90, 40, 21, 66, 23, 66, and 18, respectively. The SOLs for these constituents were 50, 89, 37, 19, 60, 20, 65, and 21, respectively. Two constituents—DP and

Improved Resolution Optical Time Stretch Imaging Based on High Efficiency In-Fiber Diffraction.

Science.gov (United States)

Wang, Guoqing; Yan, Zhijun; Yang, Lei; Zhang, Lin; Wang, Chao

2018-01-12

Most overlooked challenges in ultrafast optical time stretch imaging (OTSI) are sacrificed spatial resolution and higher optical loss. These challenges are originated from optical diffraction devices used in OTSI, which encode image into spectra of ultrashort optical pulses. Conventional free-space diffraction gratings, as widely used in existing OTSI systems, suffer from several inherent drawbacks: limited diffraction efficiency in a non-Littrow configuration due to inherent zeroth-order reflection, high coupling loss between free-space gratings and optical fibers, bulky footprint, and more importantly, sacrificed imaging resolution due to non-full-aperture illumination for individual wavelengths. Here we report resolution-improved and diffraction-efficient OTSI using in-fiber diffraction for the first time to our knowledge. The key to overcome the existing challenges is a 45° tilted fiber grating (TFG), which serves as a compact in-fiber diffraction device offering improved diffraction efficiency (up to 97%), inherent compatibility with optical fibers, and improved imaging resolution owning to almost full-aperture illumination for all illumination wavelengths. 50 million frames per second imaging of fast moving object at 46 m/s with improved imaging resolution has been demonstrated. This conceptually new in-fiber diffraction design opens the way towards cost-effective, compact and high-resolution OTSI systems for image-based high-throughput detection and measurement.

Improvement of efficiency roll-off in blue phosphorescence OLED using double dopants emissive layer

Energy Technology Data Exchange (ETDEWEB)

Yoo, Seung Il; Yoon, Ju An; Kim, Nam Ho; Kim, Jin Wook; Kang, Jin Sung; Moon, Chang-Bum [Department of Green Energy & Semiconductor Engineering, Hoseo University, Asan (Korea, Republic of); Kim, Woo Young, E-mail: wykim@hoseo.edu [Department of Green Energy & Semiconductor Engineering, Hoseo University, Asan (Korea, Republic of); Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S 4L7 (Canada)

2015-04-15

Blue phosphorescent organic light-emitting diodes (PHOLEDs) were fabricated using double dopants FIrpic and FIr6 in emissive layer (EML) with structure of ITO/NPB (700 Å)/mCP:FIrpic-8%:FIr6-x% (300 Å)/TPBi (300 Å)/Liq (20 Å)/Al (1200 Å). We optimized concentration of the second dopant FIr6 in the presence of a fixed FIrpic to observe its effect on electrical performance of PHOLED device. 24.8 cd/A of luminous efficiency was achieved by the device with dopant ratio of 8%FIrpic:4%FIr6 in EML. Efficiency roll-off was also improved 20% compared to the PHOLED device singly dopped with FIrpic or FIr6 only. Second doping proved its effect in stabilizing charge balance in EML and enhancing energy transfer of triplet excitons between two dopants. - Highlights: • We fabricated blue PHOLED with double blue phosphorescent dopants in single EML. • Efficiency roll-off was improved by using double dopant in single EML. • The host–dopant transfer is discussed by analyzing the photo-absorption and photoluminescence. • The spectroscopic analysis using multi-peak fits with a Gaussian function.

Efficient light emitting devices based on phosphorescent partially doped emissive layers

KAUST Repository

Yang, Xiaohui; Jabbour, Ghassan E.

2013-01-01

We report efficient organic light emitting devices employing an ultrathin phosphor emissive layer. The electroluminescent spectra of these devices can be tuned by introducing a low-energy emitting phosphor layer into the emission zone. Devices

Ultrathin high band gap solar cells with improved efficiencies from the world's oldest photovoltaic material.

Science.gov (United States)

Todorov, Teodor K; Singh, Saurabh; Bishop, Douglas M; Gunawan, Oki; Lee, Yun Seog; Gershon, Talia S; Brew, Kevin W; Antunez, Priscilla D; Haight, Richard

2017-09-25

Selenium was used in the first solid state solar cell in 1883 and gave early insights into the photoelectric effect that inspired Einstein's Nobel Prize work; however, the latest efficiency milestone of 5.0% was more than 30 years ago. The recent surge of interest towards high-band gap absorbers for tandem applications led us to reconsider this attractive 1.95 eV material. Here, we show completely redesigned selenium devices with improved back and front interfaces optimized through combinatorial studies and demonstrate record open-circuit voltage (V OC ) of 970 mV and efficiency of 6.5% under 1 Sun. In addition, Se devices are air-stable, non-toxic, and extremely simple to fabricate. The absorber layer is only 100 nm thick, and can be processed at 200 ˚C, allowing temperature compatibility with most bottom substrates or sub-cells. We analyze device limitations and find significant potential for further improvement making selenium an attractive high-band-gap absorber for multi-junction device applications.Wide band gap semiconductors are important for the development of tandem photovoltaics. By introducing buffer layers at the front and rear side of solar cells based on selenium; Todorov et al., reduce interface recombination losses to achieve photoconversion efficiencies of 6.5%.

External shading devices for energy efficient building

Science.gov (United States)

Shahdan, M. S.; Ahmad, S. S.; Hussin, M. A.

2018-02-01

External shading devices on a building façade is an important passive design strategy as they reduce solar radiation. Although studies have proven the benefits of external shading devices, many are designed solely for aesthetic purposes without fully considering its high potential to reduce solar radiation and glare. Furthermore, explorations into shading devices by the design team are mostly left too late in the design development phases. Hence, the paper looks into the effectiveness of external shading devices on a building towards more energy efficient building. The study aims to analyse the effects of various configurations of external shading devices towards the energy consumption of a case study building based on computer simulations. This study uses Building Information Modelling (BIM) through Autodesk Revit software as simulation tool. The constant variables for the simulation are the orientation of the building, types of glazing used by the building and the internal loads of the building. Whereas, the manipulated variable is the types of shading device used. The data were sorted according to the categories and translated into a chart. Analysis of the findings indicate that shading devices with different configurations show significant results in the energy consumption and the best configuration is the egg-crate shading devices. The study recommends that the consideration for shading device as a passive design strategy needs to be developed at the early stage of the building design.

Low-voltage and high-efficiency white organic light emitting devices with carrier balance

International Nuclear Information System (INIS)

Wei Fuxiang; Huang, Y.; Fang, L.

2010-01-01

White organic light emitting devices with the structure of ITO/m-MTDATA:x%4F-TCNQ/NPB/TBADN:EBDP:DCJTB/Bphen:Liq/LiF/Al have been demonstrated in this paper. High-mobility m-MTDATA:4F-TCNQ is added into the region between ITO and NBP to increase hole injection and transport. The high-mobility Bphen:Liq layer is added into the region between cathode and emission layers to lower cathode barrier and facilitate carrier injection. In the meanwhile, an effective carrier balance (number of holes is equal to number of electrons) between holes and electrons is considered to be one of the most important factors for improving OLEDs. During the experiment, by modulating the doping concentration of 4F-TCNQ, we can control hole injection and transport to make the carriers reach a high-level balance. The maximum current efficiency and power efficiency of devices were 9.3 cd/A and 4.6 lm/A, respectively.

Method of improving the decontaminating efficiency of ruthenium in evaporating treatment of nitric acid

International Nuclear Information System (INIS)

Kubota, Kanya; Yamana, Hajime; Takeda, Seiichiro.

1984-01-01

Purpose: To significantly improve the ruthenium removing efficiency in a nitric acid solution in an acid recovery system for the recovery of nitric acid from nitric acid liquid wastes through evaporating condensation. Method: Upon evaporating treatment of nitric acid solution containing ruthenium by supplying and heating the solution to a nitric acid evaporating device, hydrazine is previously added to the nitric acid solution. Hydrazine and intermediate reaction product of hydrazine such as azide causes a reduction reaction with intermediate reaction product of ruthenium tetraoxide to suppress the oxidation of ruthenium and thereby improve the decontaminating efficiency of ruthenium. The amount of hydrazine to be added is preferably between 20 - 500 mg/l and most suitably between 200 - 2000 mg/l per one liter of the liquid in the evaporating device. (Seki, T.)

Improved Power Conversion Efficiency of Inverted Organic Solar Cells by Incorporating Au Nanorods into Active Layer.

Science.gov (United States)

He, Yeyuan; Liu, Chunyu; Li, Jinfeng; Zhang, Xinyuan; Li, Zhiqi; Shen, Liang; Guo, Wenbin; Ruan, Shengping

2015-07-29

This Research Article describes a cooperative plasmonic effect on improving the performance of organic solar cells. When Au nanorods(NRs) are incorporated into the active layers, the designed project shows superior enhanced light absorption behavior comparing with control devices, which leads to the realization of organic solar cell with power conversion efficiency of 6.83%, accounting for 18.9% improvement. Further investigations unravel the influence of plasmonic nanostructures on light trapping, exciton generation, dissociation, and charge recombination and transport inside the thin films devices. Moreover, the introduction of high-conductivity Au NRs improves electrical conductivity of the whole device, which contributes to the enhanced fill factor.

Energy-efficient Trajectory Tracking for Mobile Devices

DEFF Research Database (Denmark)

Kjærgaard, Mikkel Baun; Bhattacharya, Sourav; Blunck, Henrik

2011-01-01

Emergent location-aware applications often require tracking trajectories of mobile devices over a long period of time. To be useful, the tracking has to be energy-efficient to avoid having a major impact on the battery life of the mobile de vice. Furthermore, when trajectory information needs to ...

Improved luminescence properties of nanocrystalline silicon based electroluminescent device by annealing

International Nuclear Information System (INIS)

Sato, Keisuke; Hirakuri, Kenji

2006-01-01

We report an annealing effect on electrical and luminescence properties of a red electroluminescent device consisting of nanocrystalline silicon (nc-Si). The red luminescence was generated by flowing the forward current into the device at a low threshold direct current (DC) forward voltage with a rise of annealing temperature up to 500 deg. C. Moreover, the luminescence of the device annealed at 500 deg. C was more intense than that of the device annealed at 200 deg. C or less under the same forward current density, because of the injection of a large quantity of carriers to the radiative recombination centers at the nc-Si surface vicinity. These were attained by a low resistivity of indium tin oxide (ITO) electrode and good contact at the ITO electrode/luminous layer interface region by the annealing treatment. The above results indicated that the annealing treatment of the device is effective for the realization of high luminance due to the improvement in the injection efficiency of carriers to the radiative recombination centers

Flow analysis for efficient design of wavy structured microchannel mixing devices

Science.gov (United States)

Kanchan, Mithun; Maniyeri, Ranjith

2018-04-01

Microfluidics is a rapidly growing field of applied research which is strongly driven by demands of bio-technology and medical innovation. Lab-on-chip (LOC) is one such application which deals with integrating bio-laboratory on micro-channel based single fluidic chip. Since fluid flow in such devices is restricted to laminar regime, designing an efficient passive modulator to induce chaotic mixing for such diffusion based flow is a major challenge. In the present work two-dimensional numerical simulation of viscous incompressible flow is carried out using immersed boundary method (IBM) to obtain an efficient design for wavy structured micro-channel mixing devices. The continuity and Navier-Stokes equations governing the flow are solved by fractional step based finite volume method on a staggered Cartesian grid system. IBM uses Eulerian co-ordinates to describe fluid flow and Lagrangian co-ordinates to describe solid boundary. Dirac delta function is used to couple both these co-ordinate variables. A tether forcing term is used to impose the no-slip boundary condition on the wavy structure and fluid interface. Fluid flow analysis by varying Reynolds number is carried out for four wavy structure models and one straight line model. By analyzing fluid accumulation zones and flow velocities, it can be concluded that straight line structure performs better mixing for low Reynolds number and Model 2 for higher Reynolds number. Thus wavy structures can be incorporated in micro-channels to improve mixing efficiency.

Improvement in chest compression quality using a feedback device (CPRmeter): a simulation randomized crossover study.

Science.gov (United States)

Buléon, Clément; Parienti, Jean-Jacques; Halbout, Laurent; Arrot, Xavier; De Facq Régent, Hélène; Chelarescu, Dan; Fellahi, Jean-Luc; Gérard, Jean-Louis; Hanouz, Jean-Luc

2013-10-01

Cardiac arrest survival depends on celerity and efficiency of life support action. Guidelines emphasized the chest compression (CC) quality and feedback devices are encouraged. The purpose is to study the impact of the CPRmeter feedback device on resuscitation performed by untrained rescuers. This is a prospective randomized crossover study on manikins (Resusci Anne). One hundred and forty four students inexperienced in cardiopulmonary resuscitation representing untrained rescuers were included. Participants performed 2 minutes of CC without interruption with (group G) or without (group B) feedback. Four months passed between the 2 crossover phases to avoid resilience effect. Data collected by the CPRmeter device were: CC rate, depth and release. Efficient CC rate ([simultaneous and correct CC rate, depth and release] primary outcome) (absolute difference [95% CI]) was significantly improved in group G (71%) compared to group B (26%; [45 {36-55}]; P 38 mm) was significantly improved in group G (85%) compared to group B (43%; [42 {33-52}]; P < .0001). Adequate CC rate (90-120/min) was significantly improved in group G (81%) compared to group B (56%; [25 {15-35}]; P < .0001). The average CC rate and depth in group G were significantly less dispersed around the mean compared to group B (test of variance P < .007; P < .015 respectively). The use of the CPRmeter significantly improved CC quality performed by students inexperienced in cardiopulmonary resuscitation. © 2013.

Algorithm of Energy Efficiency Improvement for Intelligent Devices in Railway Transport

Directory of Open Access Journals (Sweden)

Beinaroviča Anna

2016-07-01

Full Text Available The present paper deals with the use of systems and devices with artificial intelligence in the motor vehicle driving. The main objective of transport operations is a transportation planning with minimum energy consumption. There are various methods for energy saving, and the paper discusses one of them – proper planning of transport operations. To gain proper planning it is necessary to involve the system and devices with artificial intelligence. They will display possible developments in the choice of one or another transport plan. Consequently, it can be supposed how much the plan is effective against the spent energy. The intelligent device considered in this paper consists of an algorithm, a database, and the internet for the connection to other intelligent devices. The main task of the target function is to minimize the total downtime at intermediate stations. A specific unique PHP-based computer model was created. It uses the MySQL database for simulation data storage and processing. Conclusions based on the experiments were made. The experiments showed that after optimization, a train can pass intermediate stations without making multiple stops breaking and accelerating, which leads to decreased energy consumption.

IMPROVING TACONITE PROCESSING PLANT EFFICIENCY BY COMPUTER SIMULATION, Final Report

Energy Technology Data Exchange (ETDEWEB)

William M. Bond; Salih Ersayin

2007-03-30

This project involved industrial scale testing of a mineral processing simulator to improve the efficiency of a taconite processing plant, namely the Minorca mine. The Concentrator Modeling Center at the Coleraine Minerals Research Laboratory, University of Minnesota Duluth, enhanced the capabilities of available software, Usim Pac, by developing mathematical models needed for accurate simulation of taconite plants. This project provided funding for this technology to prove itself in the industrial environment. As the first step, data representing existing plant conditions were collected by sampling and sample analysis. Data were then balanced and provided a basis for assessing the efficiency of individual devices and the plant, and also for performing simulations aimed at improving plant efficiency. Performance evaluation served as a guide in developing alternative process strategies for more efficient production. A large number of computer simulations were then performed to quantify the benefits and effects of implementing these alternative schemes. Modification of makeup ball size was selected as the most feasible option for the target performance improvement. This was combined with replacement of existing hydrocyclones with more efficient ones. After plant implementation of these modifications, plant sampling surveys were carried out to validate findings of the simulation-based study. Plant data showed very good agreement with the simulated data, confirming results of simulation. After the implementation of modifications in the plant, several upstream bottlenecks became visible. Despite these bottlenecks limiting full capacity, concentrator energy improvement of 7% was obtained. Further improvements in energy efficiency are expected in the near future. The success of this project demonstrated the feasibility of a simulation-based approach. Currently, the Center provides simulation-based service to all the iron ore mining companies operating in northern

Reliability and efficiency upgrades of power systems operation by implementing intelligent electronic devices with synchrophasor measurement technology support

OpenAIRE

Mokeev Alexey

2017-01-01

This paper reviews issues of reliability and efficiency upgrades of power systems functions by means of a widespread implementation of intelligent electronic devices (IED) in various purposes supporting synchrophasor measurement technology. Thus, such issues as IED’s operational analysis in the conditions of electromagnetic and electromechanical transient processes and synthesis of digital filters that improve static and dynamic responses of these devices play an important role in their devel...

The Image Transceiver Device: Studies of Improved Physical Design.

Science.gov (United States)

David, Yitzhak; Efron, Uzi

2008-07-25

The Image Transceiver Device (ITD) design is based on combining LCOS micro-display, image processing tools and back illuminated APS imager in single CMOS chip [1]. The device is under development for Head-Mounted Display applications in augmented and virtual reality systems. The main issues with the present design are a high crosstalk of the backside imager and the need to shield the pixel circuitry from the photocharges generated in the silicon substrate. In this publication we present a modified, "deep p-well" ITD pixel design, which provides a significantly reduced crosstalk level, as well as an effective shielding of photo-charges for the pixel circuitry. The simulation performed using Silvaco software [ATLAS Silicon Device Simulator, Ray Trace and Light Absorption programs, Silvaco International, 1998] shows that the new approach provides high photo response and allows increasing the optimal thickness of the die over and above the 10-15 micrometers commonly used for back illuminated imaging devices, thereby improving its mechanical ruggedness following the thinning process and also providing a more efficient absorption of the long wavelength photons. The proposed deep p-well pixel structure is also a technology solution for the fabrication of high performance back illuminated CMOS image sensors.

Atmospheric Pressure Chemical Vapor Deposition of CdTe for High-Efficiency Thin-Film PV Devices; Annual Report, 26 January 1998-25 January 1999

Energy Technology Data Exchange (ETDEWEB)

Meyers, P. V. [ITN Energy Systems, Wheat Ridge, Colorado (US); Kee, R.; Wolden, C.; Raja, L.; Kaydanov, V.; Ohno, T.; Collins, R.; Aire, M.; Kestner, J. [Colorado School of Mines, Golden, Colorado (US); Fahrenbruch, A. [ALF, Inc., Stanford, California (US)

1999-09-30

ITN's 3-year project, titled ''Atmospheric Pressure Chemical Vapor Deposition (APCVD) of CdTe for High-Efficiency Thin-Film Photovoltaic (PV) Devices,'' has the overall objectives of improving thin-film CdTe PV manufacturing technology and increasing CdTe PV device power conversion efficiency. CdTe deposition by APCVD employs the same reaction chemistry as has been used to deposit 16%-efficient CdTe PV films, i.e., close-spaced sublimation, but employs forced convection rather than diffusion as a mechanism of mass transport. Tasks of the APCVD program center on demonstrating APCVD of CdTe films, discovering fundamental mass-transport parameters, applying established engineering principles to the deposition of CdTe films, and verifying reactor design principles that could be used to design high-throughput, high-yield manufacturing equipment. Additional tasks relate to improved device measurement and characterization procedures that can lead to a more fundamental understanding of CdTe PV device operation, and ultimately, to higher device conversion efficiency and greater stability. Specifically, under the APCVD program, device analysis goes beyond conventional one-dimensional device characterization and analysis toward two-dimension measurements and modeling. Accomplishments of the first year of the APCVD subcontract include: selection of the Stagnant Flow Reactor design concept for the APCVD reactor, development of a detailed reactor design, performance of detailed numerical calculations simulating reactor performance, fabrication and installation of an APCVD reactor, performance of dry runs to verify reactor performance, performance of one-dimensional modeling of CdTe PV device performance, and development of a detailed plan for quantification of grain-boundary effects in polycrystalline CdTe devices.

Highly efficient red electrophosphorescent devices at high current densities

International Nuclear Information System (INIS)

Wu Youzhi; Zhu Wenqing; Zheng Xinyou; Sun, Runguang; Jiang Xueyin; Zhang Zhilin; Xu Shaohong

2007-01-01

Efficiency decrease at high current densities in red electrophosphorescent devices is drastically restrained compared with that from conventional electrophosphorescent devices by using bis(2-methyl-8-quinolinato)4-phenylphenolate aluminum (BAlq) as a hole and exciton blocker. Ir complex, bis(2-(2'-benzo[4,5-α]thienyl) pyridinato-N,C 3' ) iridium (acetyl-acetonate) is used as an emitter, maximum external quantum efficiency (QE) of 7.0% and luminance of 10000cd/m 2 are obtained. The QE is still as high as 4.1% at higher current density J=100mA/cm 2 . CIE-1931 co-ordinates are 0.672, 0.321. A carrier trapping mechanism is revealed to dominate in the process of electroluminescence

A high-efficiency solution-deposited thin-film photovoltaic device

Energy Technology Data Exchange (ETDEWEB)

Mitzi, David B; Yuan, Min; Liu, Wei; Chey, S Jay; Schrott, Alex G [IBM T. J. Watson Research Center, Yorktown Heights, NY (United States); Kellock, Andrew J; Deline, Vaughn [IBM Almaden Research Center, San Jose, CA (United States)

2008-10-02

High-quality Cu(In,Ga)Se{sub 2} (CIGS) films are deposited from hydrazine-based solutions and are employed as absorber layers in thin-film photovoltaic devices. The CIGS films exhibit tunable stoichiometry and well-formed grain structure without requiring post-deposition high-temperature selenium treatment. Devices based on these films offer power conversion efficiencies of 10% (AM1.5 illumination). (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Improving the energy efficiency of mine fan assemblages

International Nuclear Information System (INIS)

De Souza, Euler

2015-01-01

Energy associated with ventilating an underground operation comprises a significant portion of a mine operation's base energy demand and is consequently responsible for a large percentage of the total operating costs. Ventilation systems may account from 25 to 40% of the total energy costs and 40–50% of the energy consumption of a mine operation. Fans are the most important mechanical devices used to ventilate underground mines and the total fan power installed in a single mine operation can easily exceed 10,000 kW. Investigations of a number of mine main fan installations have determined their assemblage to be, in general, very energy inefficient. The author has found that 40–80% of the energy consumed by a main fan is used to overcome the resistance of fan assemblage components. This paper presents how engineering design principles can be applied to improve the performance and efficiency of fan installations, resulting in substantial reductions in power consumption, operating cost and greenhouse gas emissions. A detailed case study is presented to demonstrate that, by designing fan assemblages using proper engineering concepts of fluid physics and industrial ventilation design, main fan systems will operate at efficiencies well above 80–90% (compared to common operating efficiencies of between 20 and 65%), resulting in a drastic reduction in a mine's overall costs and base electrical and energy loads. - Highlights: • Increases in fan assemblage efficiencies with minimum capital investment. • Improved designs for substantial fan power and operating cost savings. • General solutions and tactics for improving existing main fan installations. • Case study presented to demonstrate proper design of fan assemblages.

Electroluminescent efficiency of alternating current thick film devices using ZnS:Cu,Cl phosphor

International Nuclear Information System (INIS)

Sharma, Gaytri; Han, Sang Do; Kim, Jung Duk; Khatkar, Satyender P.; Rhee, Young Woo

2006-01-01

ZnS:Cu,Cl phosphor is prepared with the help of low intensity milling of the precursor material in two step firing process. The synthesized phosphor is used for the preparation of alternating current thick film electroluminescent (ACTFEL) devices with screen-printing method. The commission international de l'Eclairge (CIE) color co-ordinates of the ACTFEL devices prepared by these phosphor layers shows a shift from bluish-green to green region with the change in the amount of Cu in the phosphor. The various parameters to improve the efficiency and luminance of the devices have also been investigated. The brightness of the ac thick film EL device depends on the particle size of the phosphor, crystallinity, amount of binding material and applied voltage. The EL device fabricated with phosphor having average particle size of 25 μm shows maximum luminescence, when 60% phosphor concentration is used with respect to binding material. EL intensity is also linearly dependent on frequency. It is due the increase of excitation chances of the host matrix or dopant ions with increasing frequency

Improving power conversion efficiency of perovskite solar cells by cooperative LSPR of gold-silver dual nanoparticles

Institute of Scientific and Technical Information of China (English)

Peng Liu; Cong-hua Zhou; Bing-chu Yang; Gang Liu; Run-sheng Wu; Chu-jun Zhang; Fang Wan; Shui-gen Li; Jun-liang Yang; Yong-li Gao

2017-01-01

Enhancing optical and electrical performances is effective in improving power conversion efficiency of photovoltaic devices.Here,gold and silver dual nanoparticles were imported and embedded in the hole transport layer of perovskite solar cells.Due to the cooperative localized surface plasmon resonance of these two kinds of metal nanostructures,light harvest of perovskite material layer and the electrical performance of device were improved,which finally upgraded short circuit current density by 10.0％,and helped to increase power conversion efficiency from 10.4％ to 11.6％ under AM 1.5G illumination with intensity of 100 mW/cm2.In addition,we explored the influence of silver and gold nanoparticles on charge carrier generation,dissociation,recombination,and transportation inside perovskite solar cells.

Reliability and efficiency upgrades of power systems operation by implementing intelligent electronic devices with synchrophasor measurement technology support

Directory of Open Access Journals (Sweden)

Mokeev Alexey

2017-01-01

Full Text Available This paper reviews issues of reliability and efficiency upgrades of power systems functions by means of a widespread implementation of intelligent electronic devices (IED in various purposes supporting synchrophasor measurement technology. Thus, such issues as IED’s operational analysis in the conditions of electromagnetic and electromechanical transient processes and synthesis of digital filters that improve static and dynamic responses of these devices play an important role in their development.

Charge transfer through amino groups-small molecules interface improving the performance of electroluminescent devices

Science.gov (United States)

Havare, Ali Kemal; Can, Mustafa; Tozlu, Cem; Kus, Mahmut; Okur, Salih; Demic, Şerafettin; Demirak, Kadir; Kurt, Mustafa; Icli, Sıddık

2016-05-01

A carboxylic group functioned charge transporting was synthesized and self-assembled on an indium tin oxide (ITO) anode. A typical electroluminescent device [modified ITO/TPD (50 nm)/Alq3 (60 nm)/LiF (2 nm)/(120 nm)] was fabricated to investigate the effect of the amino groups-small molecules interface on the characteristics of the device. The increase in the surface work function of ITO is expected to facilitate the hole injection from the ITO anode to the Hole Transport Layer (HTL) in electroluminescence. The modified electroluminescent device could endure a higher current and showed a much higher luminance than the nonmodified one. For the produced electroluminescent devices, the I-V characteristics, optical characterization and quantum yields were performed. The external quantum efficiency of the modified electroluminescent device is improved as the result of the presence of the amino groups-small molecules interface.

The Image Transceiver Device: Studies of Improved Physical Design

Directory of Open Access Journals (Sweden)

Uzi Efron

2008-07-01

Full Text Available The Image Transceiver Device (ITD design is based on combining LCOS micro-display, image processing tools and back illuminated APS imager in single CMOS chip [1]. The device is under development for Head-Mounted Display applications in augmented and virtual reality systems. The main issues with the present design are a high crosstalk of the backside imager and the need to shield the pixel circuitry from the photocharges generated in the silicon substrate. In this publication we present a modified, “deep p-well” ITD pixel design, which provides a significantly reduced crosstalk level, as well as an effective shielding of photo-charges for the pixel circuitry. The simulation performed using Silvaco software [ATLAS Silicon Device Simulator, Ray Trace and Light Absorption programs, Silvaco International, 1998] shows that the new approach provides high photo response and allows increasing the optimal thickness of the die over and above the 10-15 micrometers commonly used for back illuminated imaging devices, thereby improving its mechanical ruggedness following the thinning process and also providing a more efficient absorption of the long wavelength photons. The proposed deep p-well pixel structure is also a technology solution for the fabrication of high performance back illuminated CMOS image sensors.

A Improved Seabed Surface Sand Sampling Device

Science.gov (United States)

Luo, X.

2017-12-01

In marine geology research it is necessary to obtain a suf fcient quantity of seabed surface samples, while also en- suring that the samples are in their original state. Currently,there are a number of seabed surface sampling devices available, but we fnd it is very diffcult to obtain sand samples using these devices, particularly when dealing with fne sand. Machine-controlled seabed surface sampling devices are also available, but generally unable to dive into deeper regions of water. To obtain larger quantities of seabed surface sand samples in their original states, many researchers have tried to improve upon sampling devices,but these efforts have generally produced ambiguous results, in our opinion.To resolve this issue, we have designed an improved andhighly effective seabed surface sand sampling device that incorporates the strengths of a variety of sampling devices. It is capable of diving into deepwater to obtain fne sand samples and is also suited for use in streams, rivers, lakes and seas with varying levels of depth (up to 100 m). This device can be used for geological mapping, underwater prospecting, geological engineering and ecological, environmental studies in both marine and terrestrial waters.

Remarkably High Conversion Efficiency of Inverted Bulk Heterojunction Solar Cells: From Ultrafast Laser Spectroscopy and Electron Microscopy to Device Fabrication and Optimization

KAUST Repository

Alsulami, Qana

2016-04-10

In organic donor-acceptor systems, ultrafast interfacial charge transfer (CT), charge separation (CS), and charge recombination (CR) are key determinants of the overall performance of photovoltaic devices. However, a profound understanding of these photophysical processes at device interfaces remains superficial, creating a major bottleneck that circumvents advancements and the optimization of these solar cells. Here, results from time-resolved laser spectroscopy and high-resolution electron microscopy are examined to provide the fundamental information necessary to fabricate and optimize organic solar cell devices. In real time, CT and CS are monitored at the interface between three fullerene acceptors (FAs) (PC71BM, PC61BM, and IC60BA) and the PTB7-Th donor polymer. Femtosecond transient absorption (fs-TA) data demonstrates that photoinduced electron transfer from the PTB7-Th polymer to each FA occurs on the sub-picosecond time scale, leading to the formation of long-lived radical ions. It is also found that the power conversion efficiency improves from 2% in IC60BA-based solar cells to >9% in PC71BM-based devices, in support of our time-resolved results. The insights reported in this manuscript provide a clear understanding of the key variables involved at the device interface, paving the way for the exploitation of efficient CS and subsequently improving the photoconversion efficiency. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Energy efficiency comparison of forced-air versus resistance heating devices for perioperative hypothermia management

International Nuclear Information System (INIS)

Bayazit, Yilmaz; Sparrow, Ephraim M.

2010-01-01

Hypothermia is a state in which the temperature of a human body is below the normal temperature, with the onset of the hypothermic state commonly regarded as 36 o C. This state may be encountered due to exposure to a very cold environment in the outdoors or, surprisingly, in a hospital operating room. In the latter situation, the diminution of metabolic heat generation, coupled with moderate temperatures in the surroundings and absence of a covering over the afflicted parts of the body, creates the possibility of hypothermia. There are several available devices that are designed to ward off the onset of hypothermia. These currently most frequently used devices can be placed in two categories: (a) convective air warming and (b) direct-contact heat conduction. The warming principles that underlie these two approaches are distinctly different. Furthermore, the energy efficiencies of the two approaches differ significantly. The energy penalty which results from these different efficiencies may be compounded by the fact that the portion of the input energies to these devices which escapes into the operating room ambient must be extracted to maintain a comfortable temperature for the surgical staff. Since energy-extracting equipments such as air-conditioning machines are far from being perfectly efficient, the heat-extraction process also introduces wasted energy. Experiments were performed to determine the energy-utilization efficiencies of the representative devices in the two categories cited above. This information, taken together with the known efficiencies of air-conditioning machines, enabled an overall efficiency encompassing both the therapeutic device and the heat-extraction device to be calculated. The experimental data revealed that the specifics of individual devices within a category played a larger role with regard to energy efficiency than did the category itself.

Energy efficiency comparison of forced-air versus resistance heating devices for perioperative hypothermia management

Energy Technology Data Exchange (ETDEWEB)

Bayazit, Yilmaz; Sparrow, Ephraim M. [Laboratory for Heat Transfer and Fluid Flow Practice, Department of Mechanical Engineering, University of Minnesota, 111 Church Street, SE, Minneapolis, MN 55455-0111 (United States)

2010-03-15

Hypothermia is a state in which the temperature of a human body is below the normal temperature, with the onset of the hypothermic state commonly regarded as 36 C. This state may be encountered due to exposure to a very cold environment in the outdoors or, surprisingly, in a hospital operating room. In the latter situation, the diminution of metabolic heat generation, coupled with moderate temperatures in the surroundings and absence of a covering over the afflicted parts of the body, creates the possibility of hypothermia. There are several available devices that are designed to ward off the onset of hypothermia. These currently most frequently used devices can be placed in two categories: (a) convective air warming and (b) direct-contact heat conduction. The warming principles that underlie these two approaches are distinctly different. Furthermore, the energy efficiencies of the two approaches differ significantly. The energy penalty which results from these different efficiencies may be compounded by the fact that the portion of the input energies to these devices which escapes into the operating room ambient must be extracted to maintain a comfortable temperature for the surgical staff. Since energy-extracting equipments such as air-conditioning machines are far from being perfectly efficient, the heat-extraction process also introduces wasted energy. Experiments were performed to determine the energy-utilization efficiencies of the representative devices in the two categories cited above. This information, taken together with the known efficiencies of air-conditioning machines, enabled an overall efficiency encompassing both the therapeutic device and the heat-extraction device to be calculated. The experimental data revealed that the specifics of individual devices within a category played a larger role with regard to energy efficiency than did the category itself. (author)

Highly efficient tandem organic light-emitting devices employing an easily fabricated charge generation unit

Science.gov (United States)

Yang, Huishan; Yu, Yaoyao; Wu, Lishuang; Qu, Biao; Lin, Wenyan; Yu, Ye; Wu, Zhijun; Xie, Wenfa

2018-02-01

We have realized highly efficient tandem organic light-emitting devices (OLEDs) employing an easily fabricated charge generation unit (CGU) combining 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile with ultrathin bilayers of CsN3 and Al. The charge generation and separation processes of the CGU have been demonstrated by studying the differences in the current density-voltage characteristics of external-carrier-excluding devices. At high luminances of 1000 and 10000 cd/m2, the current efficiencies of the phosphorescent tandem device are about 2.2- and 2.3-fold those of the corresponding single-unit device, respectively. Simultaneously, an efficient tandem white OLED exhibiting high color stability and warm white emission has also been fabricated.

SU-F-T-163: Improve Proton Therapy Efficiency: Report of a Workshop

Energy Technology Data Exchange (ETDEWEB)

Zheng, Y [Procure Proton Therapy Center, Oklahoma City, OK (United States); Flanz, J [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Mah, D [Procure Treatment Center, Somerset, NJ (United States); Pankuch, M; Kreydick, B [Northwestern Medicine Proton Center, Warrenville, IL (United States); Beltran, C [Mayo Clinic, Rochester, MN (United States); Robison, B; Schreuder, A [Provision Healthcare Partners, Knoxville, TN (United States)

2016-06-15

Purpose: The technology of proton therapy, especially the pencil beam scanning technique, is evolving very quickly. However, the efficiency of proton therapy seems to lag behind conventional photon therapy. The purpose of the abstract is to report on the findings of a workshop on improvement of QA, planning and treatment efficiency in proton therapy. Methods: A panel of physicists, clinicians, and vendor representatives from over 18 institutions in the United States and internationally were convened in Knoxville, Tennessee in November, 2015. The panel discussed several topics on how to improve proton therapy efficiency, including 1) lean principle and failure mode and effects analysis, 2) commissioning and machine QA, 3) treatment planning, optimization and evaluation, 4) patient positioning and IGRT, 5) vendor liaison and machine availability, and 6) staffing, education and training. Results: The relative time needed for machine QA, treatment planning & check in proton therapy was found to range from 1 to 2.5 times of that in photon therapy. Current status in proton QA, planning and treatment was assessed. Key areas for efficiency improvement, such as elimination of unnecessary QA items or steps and development of efficient software or hardware tools, were identified. A white paper to summarize our findings is being written. Conclusion: It is critical to improve efficiency by developing reliable proton beam lines, efficient software tools on treatment planning, optimization and evaluation, and dedicated proton QA device. Conscious efforts and collaborations from both industry leaders and proton therapy centers are needed to achieve this goal and further advance the technology of proton therapy.

Platform for efficient switching between multiple devices in the intensive care unit.

Science.gov (United States)

De Backere, F; Vanhove, T; Dejonghe, E; Feys, M; Herinckx, T; Vankelecom, J; Decruyenaere, J; De Turck, F

2015-01-01

This article is part of the Focus Theme of METHODS of Information in Medicine on "Managing Interoperability and Complexity in Health Systems". Handheld computers, such as tablets and smartphones, are becoming more and more accessible in the clinical care setting and in Intensive Care Units (ICUs). By making the most useful and appropriate data available on multiple devices and facilitate the switching between those devices, staff members can efficiently integrate them in their workflow, allowing for faster and more accurate decisions. This paper addresses the design of a platform for the efficient switching between multiple devices in the ICU. The key functionalities of the platform are the integration of the platform into the workflow of the medical staff and providing tailored and dynamic information at the point of care. The platform is designed based on a 3-tier architecture with a focus on extensibility, scalability and an optimal user experience. After identification to a device using Near Field Communication (NFC), the appropriate medical information will be shown on the selected device. The visualization of the data is adapted to the type of the device. A web-centric approach was used to enable extensibility and portability. A prototype of the platform was thoroughly evaluated. The scalability, performance and user experience were evaluated. Performance tests show that the response time of the system scales linearly with the amount of data. Measurements with up to 20 devices have shown no performance loss due to the concurrent use of multiple devices. The platform provides a scalable and responsive solution to enable the efficient switching between multiple devices. Due to the web-centric approach new devices can easily be integrated. The performance and scalability of the platform have been evaluated and it was shown that the response time and scalability of the platform was within an acceptable range.

A new device to test cutting efficiency of mechanical endodontic instruments

Science.gov (United States)

Rubini, Alessio Giansiracusa; Plotino, Gianluca; Al-Sudani, Dina; Grande, Nicola M.; Putorti, Ermanno; Sonnino, GianPaolo; Cotti, Elisabetta; Testarelli, Luca; Gambarini, Gianluca

2014-01-01

Background The purpose of the present study was to introduce a new device specifically designed to evaluate the cutting efficiency of mechanically driven endodontic instruments. Material/Methods Twenty new Reciproc R25 (VDW, Munich, Germany) files were used to be investigated in the new device developed to test the cutting ability of endodontic instruments. The device consists of a main frame to which a mobile plastic support for the hand-piece is connected and a stainless-steel block containing a Plexiglas block against which the cutting efficiency of the instruments was tested. The length of the block cut in 1 minute was measured in a computerized program with a precision of 0.1mm. The instruments were activated by using a torque-controlled motor (Silver Reciproc; VDW, Munich, Germany) in a reciprocating movement by the “Reciproc ALL” program (Group 1) and in counter-clockwise rotation at 300 rpm (Group 2). Mean and standard deviations of each group were calculated and data were statistically analyzed with a one-way ANOVA test (P0.05). Conclusions The cutting testing device evaluated in the present study was reliable and easy to use and may be effectively used to test cutting efficiency of both rotary and reciprocating mechanical endodontic instruments. PMID:24603777

High-efficiency white organic light-emitting devices with a non-doped yellow phosphorescent emissive layer

Energy Technology Data Exchange (ETDEWEB)

Zhao Juan; Yu Junsheng, E-mail: jsyu@uestc.edu.cn; Hu Xiao; Hou Menghan; Jiang Yadong

2012-03-30

Highly efficient phosphorescent white organic light-emitting devices (PHWOLEDs) with a simple structure of ITO/TAPC (40 nm)/mCP:FIrpic (20 nm, x wt.%)/bis[2-(4-tertbutylphenyl)benzothiazolato-N,C{sup 2} Prime ] iridium (acetylacetonate) (tbt){sub 2}Ir(acac) (y nm)/Bphen (30 nm)/Mg:Ag (200 nm) have been developed, by inserting a thin layer of non-doped yellow phosphorescent (tbt){sub 2}Ir(acac) between doped blue emitting layer (EML) and electron transporting layer. By changing the doping concentration of the blue EML and the thickness of the non-doped yellow EML, a PHWOLED comprised of higher blue doping concentration and thinner yellow EML achieves a high current efficiency of 31.7 cd/A and Commission Internationale de l'Eclairage coordinates of (0.33, 0.41) at a luminance of 3000 cd/m{sup 2} could be observed. - Highlights: Black-Right-Pointing-Pointer We introduce a simplified architecture for phosphorescent white organic light-emitting device. Black-Right-Pointing-Pointer The key concept of device fabrication is combination of doped blue emissive layer (EML) with non-doped ultra-thin yellow EML. Black-Right-Pointing-Pointer Doping concentration of the blue EML and thickness of the yellow EML are sequentially adjusted. Black-Right-Pointing-Pointer High device performance is achieved due to improved charge carrier balance as well as two parallel emission mechanisms in the EMLs.

Efficient Protection of Android Applications through User Authentication Using Peripheral Devices

Directory of Open Access Journals (Sweden)

Jinseong Kim

2018-04-01

Full Text Available Android applications store large amounts of sensitive information that may be exposed and exploited. To prevent this security risk, some applications such as Syrup and KakaoTalk use physical device values to authenticate or encrypt application data. However, by manipulating these physical device values, an attacker can circumvent the authentication by executing a Same Identifier Attack and obtain the same application privileges as the user. In our work, WhatsApp, KakaoTalk, Facebook, Amazon, and Syrup were subjected to the Same Identifier Attack, and it was found that an attacker could gain the same privileges as the user, in all five applications. To solve such a problem, we propose a technical scheme—User Authentication using Peripheral Devices. We applied the proposed scheme to a Nexus 5X smartphone running Android version 7.1 and confirmed that the average execution time was 0.005 s, which does not affect the other applications’ execution significantly. We also describe the security aspects of the proposed scheme and its compatibility with the Android platform and other applications. The proposed scheme is practical and efficient in terms of resource usage; therefore, it will be useful for Android users to improve Android application security.

A broadband high-efficiency Doherty power amplifier using symmetrical devices

Science.gov (United States)

Cheng, Zhiqun; Zhang, Ming; Li, Jiangzhou; Liu, Guohua

2018-04-01

This paper proposes a method for broadband and high-efficiency amplification of Doherty power amplifier (DPA) using symmetric devices. In order to achieve the perfect load modulation, the carrier amplifier output circuit total power length is designed to odd multiple of 90°, and the peak amplifier output total power length is designed to even multiple of 180°. The proposed method is demonstrated by designing a broadband high-efficiency DPA using identical 10-W packaged GaN HEMT devices. Measurement results show that over 51% drain efficiency is achieved at 6-dB back-off power, over the frequency band of 1.9–2.4 GHz. Project supported by the National Natural Science Foundation of China (No. 60123456), the Zhejiang Provincial Natural Science Foundation of China (No. LZ16F010001), and the Zhejiang Provincial Public Technology Research Project (No. 2016C31070).

Improvement in the diffraction efficiency of a polymer using an ionic liquid

Directory of Open Access Journals (Sweden)

Kim Sung Ho

2018-01-01

Full Text Available In this paper, photosensitive materials for information storage devices are presented. The polymers were prepared using surface relief-grating (SRG fabrication with a diode-pumped solid-state (DPSS laser of 532 nm, and the diffraction efficiency (DE of the polymers were assessed with a low-power DPSS laser at 633 nm. However, the diffraction efficiency of the azo-functionalized epoxy-based polymer was low, even after 15 min of exposure. To improve the efficiency and reduce the time it takes for the DE measurements of the photosensitive polymer, the polymer was combined ionic liquids (ILs. Various ILs, i.e., 1-methylimidazolium chloride ([Mim]Cl from the imidazolium family of ILs and diethylammonium dihydrogen phosphate (DEAP, triethylammonium 4-aminotoluene-3-sulfonic acid (TASA and tributylmethylammonium methyl sulphate (TBMS from the ammonium family of ILs, were investigated. For the first time, it was observed that DE dramatically increased the DEAP–polymer mixture in 4 min compared to the polymer (alone and other polymer–IL mixtures. Therefore, DEAP IL could help improve the efficiency of DE measurements in a shorter time.

Working Characteristics of a Mechanical Insufflation-Exsufflation Device

Directory of Open Access Journals (Sweden)

Yan Shi

2014-01-01

Full Text Available Secretions of ventilated patients must be cleared efficiently and timely; to improve the secretion clearance efficiency of an insufflation-exsufflation device (IL-IE device and lay a foundation for the optimization of the IL-IE device, a mathematical model of the ventilation system with the IL-IE device is set up. Through the experimental and simulation research on the ventilation system, it can be concluded that, firstly, the mathematical model is proved to be authentic and reliable. Secondly, with the deposition of secretion or an increase in the respiratory compliance, the peak exsufflation airflow may be reduced. Thirdly, with a decrease in the suction pressure, the peak exsufflation airflow of the ventilated lung may rise proportionally, but the minimum pressure in the ventilated lung may descend proportionally. To improve the efficiency of the secretion clearance but not to injure the ventilated patient, the suction pressure can be elevated properly. Last, increasing the inspiratory positive airway pressure (IPAP is a method to improve the secretion clearance efficiency. This research lays a foundation for improving the secretion clearance efficiency of the IL-IE device.

High-efficiency and heavily doped organic light-emitting devices based on quench-resistant red iridium complex

Energy Technology Data Exchange (ETDEWEB)

Wang, Qi [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zhao, Juan; Wang, Jun [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Li, Ming [College of Chemistry, Sichuan University, Chengdu 610064 (China); Lu, Zhiyun, E-mail: luzhiyun@scu.edu.cn [College of Chemistry, Sichuan University, Chengdu 610064 (China)

2013-02-15

Highly efficient red phosphorescent organic light-emitting devices had been fabricated using a new iridium complex, bis[2-(9,9-dimethyl-9H-fluoren-2-yl) benzothiazolato-N,C{sup 2'}]iridium(III) (acetylacetonate) [(fbt){sub 2}Ir(acac)] as phosphor. With a high doping concentration of 15 wt%, the device exhibited a maximum luminance efficiency, power efficiency and external quantum efficiency (EQE) of 35.2 cd/A, 21.3 lm/W, 18.2%, respectively, indicating an excellent quench-resistant property of (fbt){sub 2}Ir(acac). The results are appealing towards the development of 'easy-to-make' OLEDs. It has been demonstrated that the high efficiency arises from more balanced charge carriers in the emissive layer. - Highlight: Black-Right-Pointing-Pointer We obtained efficient OLEDs based on newly synthesized quench-resistant phosphor. Black-Right-Pointing-Pointer Peak performance was obtained with 15 wt% (fbt){sub 2}Ir(acac) doped device. Black-Right-Pointing-Pointer Our devices gave one of the best performance among heavily-doped red devices. Black-Right-Pointing-Pointer Balanced carrier transport is crucial for the high performance of our devices.

Furnace devices aerodynamics optimization for fuel combustion efficiency improvement and nitrogen oxide emission reduction

Science.gov (United States)

Volkov, E. P.; Prokhorov, V. B.; Arkhipov, A. M.; Chernov, S. L.; Kirichkov, V. S.; Kaverin, A. A.

2017-11-01

MPEI conducts researches on physical and mathematical models of furnace chambers for improvement of power-generation equipment fuel combustion efficiency and ecological safety. Results of these researches are general principles of furnace aerodynamics arrangement for straight-flow burners and various fuels. It has been shown, that staged combustion arrangement with early heating and igniting with torch distribution in all furnace volume allows to obtain low carbon in fly ash and nitrogen oxide emission and also to improve boiler operation reliability with expand load adjustment range. For solid fuel combustion efficiency improvement it is practical to use high-placed and strongly down-tilted straight-flow burners, which increases high-temperature zone residence time for fuel particles. In some cases, for this combustion scheme it is possible to avoid slag-tap removal (STR) combustion and to use Dry-bottom ash removal (DBAR) combustion with tolerable carbon in fly ash level. It is worth noting that boilers with STR have very high nitrogen oxide emission levels (1200-1800 mg/m3) and narrow load adjustment range, which is determined by liquid slag output stability, so most industrially-developed countries don’t use this technology. Final decision about overhaul of boiler unit is made with regard to physical and mathematical modeling results for furnace and zonal thermal calculations for furnace and boiler as a whole. Overhaul of boilers to provide staged combustion and straight-flow burners and nozzles allows ensuring regulatory nitrogen oxide emission levels and corresponding best available technology criteria, which is especially relevant due to changes in Russian environmental regulation.

Graphene-based vdW heterostructure Induced High-efficiency Thermoelectric Devices

Science.gov (United States)

Liang, Shijun; Ang, Lay Kee

Thermoelectric material (TE) can convert the heat into electricity to provide green energy source and its performance is characterized by a figure of merit (ZT) parameter. Traditional TE materials only give ZT equal to around 1 at room temperature. But, it is believed that materials with ZT >3 will find wide applications at this low temperature range. Prior studies have implied that the interrelation between electric conductivity and lattice thermal conductivity renders the goal of engineering ZT of bulk materials to reach ZT >3. In this work, we propose a high-efficiency van del Waals (vdW) heterostructure-based thermionic device with graphene electrodes, which is able to harvest wasted heat (around 400K) based on the newly established thermionic emission law of graphene electrodes instead of Seebeck effect, to boost the efficiency of power generation over 10% around room temperature. The efficiency can be above 20% if the Schottky barrier height and cross-plane lattice thermal conductivity of transition metal dichacogenides (TMD) materials can be fine-engineered. As a refrigerator at 260 K, the efficiency is 50% to 80% of Carnot efficiency. Finally, we identify two TMD materials as the ideal candidates of graphene/TMD/graphene devices based on the state-of-art technology.

Improvements in or relating to semiconductor devices

International Nuclear Information System (INIS)

Cooper, K.; Groves, I.S.; Leigh, P.A.; McIntyre, N.; O'Hara, S.; Speight, J.D.

1980-01-01

A method of producing semiconductor devices is described consisting of a series of physical and chemical techniques which results in the production of semiconductor devices such as IMPATT diodes of DC-RF efficiency and high reliability (lifetime). The diodes can be mass produced without significant variation of the technology. One of the techniques used is the high energy proton bombardment of the semiconductor material in depth to passivate specific zones. The energy of the protons is increased in stages at intervals of less than 0.11 MeV up to a predetermined maximum energy. (UK)

Efficiency Improvements of Antenna Optimization Using Orthogonal Fractional Experiments

Directory of Open Access Journals (Sweden)

Yen-Sheng Chen

2015-01-01

Full Text Available This paper presents an extremely efficient method for antenna design and optimization. Traditionally, antenna optimization relies on nature-inspired heuristic algorithms, which are time-consuming due to their blind-search nature. In contrast, design of experiments (DOE uses a completely different framework from heuristic algorithms, reducing the design cycle by formulating the surrogates of a design problem. However, the number of required simulations grows exponentially if a full factorial design is used. In this paper, a much more efficient technique is presented to achieve substantial time savings. By using orthogonal fractional experiments, only a small subset of the full factorial design is required, yet the resultant response surface models are still effective. The capability of orthogonal fractional experiments is demonstrated through three examples, including two tag antennas for radio-frequency identification (RFID applications and one internal antenna for long-term-evolution (LTE handheld devices. In these examples, orthogonal fractional experiments greatly improve the efficiency of DOE, thereby facilitating the antenna design with less simulation runs.

Computationally efficient design of optimal output feedback strategies for controllable passive damping devices

International Nuclear Information System (INIS)

Kamalzare, Mahmoud; Johnson, Erik A; Wojtkiewicz, Steven F

2014-01-01

Designing control strategies for smart structures, such as those with semiactive devices, is complicated by the nonlinear nature of the feedback control, secondary clipping control and other additional requirements such as device saturation. The usual design approach resorts to large-scale simulation parameter studies that are computationally expensive. The authors have previously developed an approach for state-feedback semiactive clipped-optimal control design, based on a nonlinear Volterra integral equation that provides for the computationally efficient simulation of such systems. This paper expands the applicability of the approach by demonstrating that it can also be adapted to accommodate more realistic cases when, instead of full state feedback, only a limited set of noisy response measurements is available to the controller. This extension requires incorporating a Kalman filter (KF) estimator, which is linear, into the nominal model of the uncontrolled system. The efficacy of the approach is demonstrated by a numerical study of a 100-degree-of-freedom frame model, excited by a filtered Gaussian random excitation, with noisy acceleration sensor measurements to determine the semiactive control commands. The results show that the proposed method can improve computational efficiency by more than two orders of magnitude relative to a conventional solver, while retaining a comparable level of accuracy. Further, the proposed approach is shown to be similarly efficient for an extensive Monte Carlo simulation to evaluate the effects of sensor noise levels and KF tuning on the accuracy of the response. (paper)

Investigation of Unequal Planar Wireless Electricity Device for Efficient Wireless Power Transfer

Directory of Open Access Journals (Sweden)

M. H. Mohd Salleh

2017-04-01

Full Text Available This article focuses on the design and investigation of a pair of unequally sized wireless electricity (Witricity devices that are equipped with integrated planar coil strips. The proposed pair of devices consists of two different square-shaped resonator sizes of 120 mm × 120 mm and 80 mm × 80 mm, acting as a transmitter and receiver, respectively. The devices are designed, simulated and optimized using the CST Microwave Studio software prior to being fabricated and verified using a vector network analyzer (VNA. The surface current results of the coupled devices indicate a good current density at 10 mm to 30 mm distance range. This good current density demonstrates that the coupled devices’ surface has more electric current per unit area, which leads to a good performance up to 30 mm range. Hence, the results also reveal good coupling efficiency between the coupled devices, which is approximately 54.5% at up to a 30 mm distance, with both devices axially aligned. In addition, a coupling efficiency of 50% is achieved when a maximum lateral misalignment (LM of 10 mm, and a varied angular misalignment (AM from 0° to 40° are implemented to the proposed device.

Efficient white organic light-emitting devices based on blue, orange, red phosphorescent dyes

International Nuclear Information System (INIS)

Chen Ping; Duan Yu; Xie Wenfa; Zhao Yi; Hou Jingying; Liu Shiyong; Zhang Liying; Li Bin

2009-01-01

We demonstrate efficient white organic light-emitting devices (WOLEDs) based on an orange phosphorescent iridium complex bis(2-(2-fluorphenyl)-1,3-benzothiozolato-N, C 2' )iridium(acetylacetonate) in combination with blue phosphorescent dye bis[(4, 6-difluorophenyl)-pyridinato-N,C 2 )](picolinato) Ir(III) and red phosphorescent dye bis[1-(phenyl)isoquinoline] iridium (III) acetylanetonate. By introducing a thin layer of 4, 7-diphenyl-1,10-phenanthroline between blue and red emission layers, the diffusion of excitons is confined and white light can be obtained. WOLEDs with the interlayer all have a higher colour rendering index (>82) than the device without it (76). One device has the maximum current efficiency of 17.6 cd A -1 and a maximum luminance of 39 050 cd m -2 . The power efficiency is 8.7 lm W -1 at 100 cd m -2 . Furthermore, the device has good colour stability and the CIE coordinates just change from (0.394, 0.425) to (0.390, 0.426) with the luminance increasing from 630 to 4200 cd m -2 .

Flaw detection device

International Nuclear Information System (INIS)

Sasahara, Toshihiko

1998-01-01

The present invention provides a device for detecting welded portions of a reactor pressure vessel. Namely, the device of the present invention comprises (1) a casing to be disposed on the surface to be detected, (2) a probe driving means loaded to the casing, (3) a probe driven along the surface to be detected and (4) a pressure reduction means for keeping the hollow portion in the casing to an evacuated atmosphere. The casing comprises a flexible suction edge to be tightly in contact with the surface to be tested for maintaining the air tight state, (6) a guide wheel for moving the casing along the surface to be tested and (7) a handle for performing transferring operation. The flaw detection device thus constituted has following features. The working efficiency upon conducting detection is improved. The influence of the weight of the device on the detection is small. The device can be applied on the surface of a nonmagnetic material. The efficiency for the flaw detection can be improved. (I.S.)

Efficiency Intra-Cluster Device-to-Device Relay Selection for Multicast Services Based on Combinatorial Auction

Directory of Open Access Journals (Sweden)

Yong Zhang

2015-12-01

Full Text Available In Long Term Evolution-Advanced (LTE-A networks, Device-to-device (D2D communications can be utilized to enhance the performance of multicast services by leveraging D2D relays to serve nodes with worse channel conditions within a cluster. For traditional D2D relay schemes, D2D links with poor channel condition may be the bottleneck of system sum data rate. In this paper, to optimize the throughput of D2D communications, we introduce an iterative combinatorial auction algorithm for efficient D2D relay selection. In combinatorial auctions, the User Equipments (UEs that fails to correctly receive multicast data from eNodeB (eNB are viewed as bidders that compete for D2D relays, while the eNB is treated as the auctioneer. We also give properties of convergency and low-complexity and present numerical simulations to verify the efficiency of the proposed algorithm.

Evaluation of Efficiency Improvement in Vital Documentation Using RFID Devices.

Science.gov (United States)

Kimura, Eizen; Nakai, Miho; Ishihara, Ken

2016-01-01

We introduced medical devices with RFID tags and the terminal with RFID reader in our hospital. Time study was conducted in two phases. In phase I, nurses round as usual, and in phase II, the nurse round the ward with a terminal installed on a cart. This study concluded that RFID system shortens the time for vital sign documentation. However, deploying the terminals at every bedside did not contribute the more time reduction.

The Gains from Improved Market Efficiency

DEFF Research Database (Denmark)

Persson, Karl Gunnar; Ejrnæs, Mette

faster, violations of the law of one price become smaller and hence less persistent. There were also significant gains from improved market efficiency but that improvement took place after the information ‘regime’ shifted from pre-telegraphic communication to a regime with swift transmission...... of information in an era which developed a sophisticated commercial press and telegraphic communication. Improved market efficiency probably stimulated trade more than falling transport costs......This paper looks at the gains from improved market efficiency in long-distance grain trade in the second half of the 19th century when violations of the law of one price were reduced due to improved information transmission. Two markets, a major export centre, Chicago, and a major importer...

Particle collector scoops for improved exhaust in ''axisymmetric'' devices

International Nuclear Information System (INIS)

Conn, R.W.; Wolf, G.H.

1987-11-01

Application of particle collector scoops in front of the pumping ducts of axisymmetric divertor/magnetic limiter configurations is proposed. These scoops should enclose a significant fraction of the recycling particles. The resulting increase in natural particle pressure in front of the pumping ducts leads to an improved exhaust efficiency. This can permit an extension of the operational margin for density control. Alternatively, aiming at a prescribed exhaust flow in reactor-type devices such as INTOR, the pumping ducts could be reduced in aperture, leaving valuable space for other components. The lay-out of the proposed scheme depends on the heat load on the leading edge in front of the scoop and on the deflector in front of the pumping ducts. 14 refs., 5 figs

Highly efficient white organic light-emitting devices consisting of undoped ultrathin yellow phosphorescent layer

Energy Technology Data Exchange (ETDEWEB)

Liu, Shengqiang [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Ma, Zhu; Zhao, Juan [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

2013-02-15

High-efficiency white organic light-emitting devices (WOLEDs) based on an undoped ultrathin yellow light-emitting layer and a doped blue light-emitting layer were demonstrated. While the thickness of blue light-emitting layer, formed by doping a charge-trapping phosphor, iridium(III) bis(4 Prime ,6 Prime -difluorophenylpyridinato)tetrakis(1-pyrazolyl)borate (FIr6) in a wide bandgap host, was kept constant, the thickness of neat yellow emissive layer of novel phosphorescent material, bis[2-(4-tertbutylphenyl)benzothiazolato-N,C{sup 2 Prime }]iridium (acetylacetonate) [(t-bt){sub 2}Ir(acac)] was varied to optimize the device performance. The optimized device exhibited maximum luminance, current efficiency and power efficiency of 24,000 cd/m{sup 2} (at 15.2 V), 79.0 cd/A (at 1550 cd/m{sup 2}) and 40.5 lm/W (at 1000 cd/m{sup 2}), respectively. Besides, the white-light emission covered a wide range of visible spectrum, and the Commission Internationale de l'Eclairage coordinates were (0.32, 0.38) with a color temperature of 5800 K at 8 V. Moreover, high external quantum efficiency was also obtained in the high-efficiency WOLEDs. The performance enhancement was attributed to the proper thickness of (t-bt){sub 2}Ir(acac) layer that enabled adequate current density and enough phosphorescent dye to trap electrons. - Highlights: Black-Right-Pointing-Pointer Highly efficient WOLEDs based on two complementary layers were fabricated. Black-Right-Pointing-Pointer The yellow emissive layer was formed by utilizing undoping system. Black-Right-Pointing-Pointer The blue emissive layer was made by host-guest doping system. Black-Right-Pointing-Pointer The thickness of the yellow emissive layer was varied to make device optimization. Black-Right-Pointing-Pointer The optimized device achieved high power efficiency of 40.5 lm/W.

Efficient Implementation of Solvers for Linear Model Predictive Control on Embedded Devices

DEFF Research Database (Denmark)

Frison, Gianluca; Kwame Minde Kufoalor, D.; Imsland, Lars

2014-01-01

This paper proposes a novel approach for the efficient implementation of solvers for linear MPC on embedded devices. The main focus is to explain in detail the approach used to optimize the linear algebra for selected low-power embedded devices, and to show how the high-performance implementation...

Compact and high-efficiency device for Raman scattering measurement using optical fibers.

Science.gov (United States)

Mitsui, Tadashi

2014-11-01

We describe the design and development of a high-efficiency optical measurement device for operation within the small bore of a high-power magnet at low temperature. For the high-efficiency measurement of light emitted from this small region, we designed a compact confocal optics with lens focusing and tilting systems, and used a piezodriven translation stage that allows micron-scale focus control of the sample position. We designed a measurement device that uses 10 m-long optical fibers in order to avoid the influence of mechanical vibration and magnetic field leakage of high-power magnets, and we also describe a technique for minimizing the fluorescence signal of optical fibers. The operation of the device was confirmed by Raman scattering measurements of monolayer graphene on quartz glass with a high signal-to-noise ratio.

Improved efficiency in organic/inorganic hybrid solar cells by interfacial modification of ZnO nanowires with small molecules

International Nuclear Information System (INIS)

Chang, Sehoon; Park, Hyesung; Cheng, Jayce J; Rekemeyer, Paul H; Gradečak, Silvija

2014-01-01

We demonstrate improved photovoltaic performance of ZnO nanowire/poly(3-hexylthiophene) (P3HT) nanofiber hybrid devices using an interfacial modification of ZnO nanowires. Formation of cascade energy levels between the ZnO nanowire and P3HT nanofiber was achieved by interfacial modification of ZnO nanowires using small molecules tetraphenyldibenzoperiflanthene (DBP) and 3,4,9,10-perylenetetracarboxylic bisbenzimidazole (PTCBI). The successful demonstration of improved device performance owing to the cascade energy levels by small molecule modification is a promising approach toward highly efficient organic/inorganic hybrid solar cells. (paper)

Efficient fluorescent deep-blue and hybrid white emitting devices based on carbazole/benzimidazole compound

KAUST Repository

Yang, Xiaohui

2011-07-28

We report the synthesis, photophysics, and electrochemical characterization of carbazole/benzimidazole-based compound (Cz-2pbb) and efficient fluorescent deep-blue light emitting devices based on Cz-2pbb with the peak external quantum efficiency of 4.1% and Commission Internationale dÉnclairage coordinates of (0.16, 0.05). Efficient deep-blue emission as well as high triplet state energy of Cz-2pbb enables fabrication of hybrid white organic light emitting diodes with a single emissive layer. Hybrid white emitting devices based on Cz-2pbb show the peak external quantum efficiency exceeding 10% and power efficiency of 14.8 lm/W at a luminance of 500 cd/m2. © 2011 American Chemical Society.

Achieving Extreme Utilization of Excitons by an Efficient Sandwich-Type Emissive Layer Architecture for Reduced Efficiency Roll-Off and Improved Operational Stability in Organic Light-Emitting Diodes.

Science.gov (United States)

Wu, Zhongbin; Sun, Ning; Zhu, Liping; Sun, Hengda; Wang, Jiaxiu; Yang, Dezhi; Qiao, Xianfeng; Chen, Jiangshan; Alshehri, Saad M; Ahamad, Tansir; Ma, Dongge

2016-02-10

It has been demonstrated that the efficiency roll-off is generally caused by the accumulation of excitons or charge carriers, which is intimately related to the emissive layer (EML) architecture in organic light-emitting diodes (OLEDs). In this article, an efficient sandwich-type EML structure with a mixed-host EML sandwiched between two single-host EMLs was designed to eliminate this accumulation, thus simultaneously achieving high efficiency, low efficiency roll-off and good operational stability in the resulting OLEDs. The devices show excellent electroluminescence performances, realizing a maximum external quantum efficiency (EQE) of 24.6% with a maximum power efficiency of 105.6 lm W(-1) and a maximum current efficiency of 93.5 cd A(-1). At the high brightness of 5,000 cd m(-2), they still remain as high as 23.3%, 71.1 lm W(-1), and 88.3 cd A(-1), respectively. And, the device lifetime is up to 2000 h at initial luminance of 1000 cd m(-2), which is significantly higher than that of compared devices with conventional EML structures. The improvement mechanism is systematically studied by the dependence of the exciton distribution in EML and the exciton quenching processes. It can be seen that the utilization of the efficient sandwich-type EML broadens the recombination zone width, thus greatly reducing the exciton quenching and increasing the probability of the exciton recombination. It is believed that the design concept provides a new avenue for us to achieve high-performance OLEDs.

System Efficiency Improvement for Electric Vehicles Adopting a Permanent Magnet Synchronous Motor Direct Drive System

Directory of Open Access Journals (Sweden)

Chengming Zhang

2017-12-01

Full Text Available To improve the endurance mileage of electric vehicles (EVs, it is important to decrease the energy consumption of the Permanent Magnet Synchronous Motor (PMSM drive system. This paper proposes a novel loss optimization control strategy named system efficiency improvement control which can optimize both inverter and motor losses. A nonlinear power converter loss model is built to fit the nonlinear characteristics of power devices. This paper uses double Fourier integral analysis to analytically calculate the fundamental and harmonic components of motor current by which the fundamental motor loss and harmonic motor loss can be accurately analyzed. From these loss models, a whole-frequency-domain system loss model is derived and presented. Based on the system loss model, the system efficiency improvement control method applies the genetic algorithm to adjust the motor current and PWM frequency together to optimize the inverter and motor losses by which the system efficiency can be significantly improved without seriously influence on the system stability over the whole operation range of EVs. The optimal effects of system efficiency is verified by the experimental results in both Si-IGBT-based PMSM system and SiC-MOSFET-based system.

Highly efficient and heavily-doped organic light-emitting devices based on an orange phosphorescent iridium complex

International Nuclear Information System (INIS)

Zhou, Shunliang; Wang, Qi; Li, Ming; Lu, Zhiyun; Yu, Junsheng

2014-01-01

Heavily doped and highly efficient phosphorescent organic light-emitting devices (PhOLEDs) had been fabricated by utilizing an orange iridium complex, bis[2-(3′,5′-di-tert-butylbiphenyl-4-yl)benzothiazolato-N,C 2' ]iridium(III) (acetylacetonate) [(tbpbt) 2 Ir(acac)], as a phosphor. When the doping concentration of [(tbpbt) 2 Ir(acac)] reached as high as 15 wt%, the PhOLEDs exhibited a power efficiency, current efficiency, and external quantum efficiency of 24.5 lm/W, 32.1 cd/A, 15.7%, respectively, implying a promising quenching-resistant characteristics of this novel phosphor. Furthermore, the efficient white PhOLEDs had been obtained by employing (tbpbt) 2 Ir(acac) as a self-host orange emitter, indicating that (tbpbt) 2 Ir(acac) could serve as a promising phosphor to fabricate white organic light-emitting devices with simplified manufacturing process. - Highlights: • Efficient phosphorescent devices were fabricated. • Optimized phosphor doping ratio reached as high as 15 wt%. • The results proved a promising quench-resistant property of the phosphor. • Efficient white devices based on this phosphor as self-host layer had been realized

Highly efficient and heavily-doped organic light-emitting devices based on an orange phosphorescent iridium complex

Energy Technology Data Exchange (ETDEWEB)

Zhou, Shunliang; Wang, Qi [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Li, Ming [College of Chemistry, Sichuan University, Chengdu, 610064 (China); Lu, Zhiyun, E-mail: luzhiyun@scu.edu.cn [College of Chemistry, Sichuan University, Chengdu, 610064 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

2014-10-15

Heavily doped and highly efficient phosphorescent organic light-emitting devices (PhOLEDs) had been fabricated by utilizing an orange iridium complex, bis[2-(3′,5′-di-tert-butylbiphenyl-4-yl)benzothiazolato-N,C{sup 2'}]iridium(III) (acetylacetonate) [(tbpbt){sub 2}Ir(acac)], as a phosphor. When the doping concentration of [(tbpbt){sub 2}Ir(acac)] reached as high as 15 wt%, the PhOLEDs exhibited a power efficiency, current efficiency, and external quantum efficiency of 24.5 lm/W, 32.1 cd/A, 15.7%, respectively, implying a promising quenching-resistant characteristics of this novel phosphor. Furthermore, the efficient white PhOLEDs had been obtained by employing (tbpbt){sub 2}Ir(acac) as a self-host orange emitter, indicating that (tbpbt){sub 2}Ir(acac) could serve as a promising phosphor to fabricate white organic light-emitting devices with simplified manufacturing process. - Highlights: • Efficient phosphorescent devices were fabricated. • Optimized phosphor doping ratio reached as high as 15 wt%. • The results proved a promising quench-resistant property of the phosphor. • Efficient white devices based on this phosphor as self-host layer had been realized.

An analysis of limits for part load efficiency improvement with VVA devices

International Nuclear Information System (INIS)

Knop, Vincent; Mattioli, Leonardo

2015-01-01

Highlights: • Variable valve actuation aims at reducing pumping losses for spark-ignition engines. • Fully unthrottled operation is never reached because of combustion degradation. • Present paper quantifies the combustion degradation origins for various strategies. • Fully unthrottled CAI combustion mode is a non-combustion-limited alternative. • Combustion limitation is, however, replaced by a heat loss limitation. - Abstract: The implementation of Variable Valve Actuation (VVA) in Spark-Ignition (SI) engines generally aims at increasing part-load efficiency by reducing pumping losses. However, any innovative valve strategy has effects on the combustion process itself, introducing new limitations and mitigating the fuel consumption benefits. The experimental analysis of such valve strategies identifies the optimum settings but does not explain the origin of benefits and the sources of unexpected drawbacks. In the present study, the experimentally-optimised operating conditions for different valve strategies were numerically compared with 3D CFD to gain knowledge about causes for efficiency benefits and consequences of valve strategy on combustion progress. We compared standard SI operation in a single-cylinder port-fuel injection gasoline engine to mixture leaning, early intake valve closure (Miller cycle), late intake valve closure (Atkinson cycle), as well as Controlled Auto-Ignition (CAI). All alternative methods reduced pumping work and improved fuel consumption. However, all alternative methods also altered combustion progress and thermodynamic state within the combustion chamber, so that the observed fuel consumption benefits never reached the expected values. An energy balance provided the additional losses induced by each strategy while in-cylinder turbulence and temperature quantification helped explain the trends in combustion speed.

Design principle for efficient charge separation at the donor-acceptor interface for high performance organic solar cell device

Science.gov (United States)

Nie, Wanyi; Gupta, Gautam; Crone, Brian; Wang, Hsing-Lin; Mohite, Aditya; MPA-11 Material synthesis and integrated device Team; MPA-chemistry Team

2014-03-01

The performance of donor (D) /acceptor (A) structure based organic electronic devices, such as solar cell, light emitting devices etc., relays on the charge transfer process at the interface dramatically. In organic solar cell, the photo-induced electron-hole pair is tightly bonded and will form a charge transfer (CT) state at the D/A interface after dissociation. There is a large chance for them to recombine through CT state and thus is a major loss that limit the overall performance. Here, we report three different strategies that allow us to completely suppress the exciplex (or charge transfer state) recombination between any D/A system. We observe that the photocurrent increases by 300% and the power conversion efficiency increases by 4-5 times simply by inserting a spacer layer in the form of an a) insulator b) Oliogomer or using a c) heavy atom at the donor-acceptor interface in a P3HT/C60 bilayer device. By using those different functional mono layers, we successfully suppressed the exciplex recombination in evidence of increased photocurrent and open circuit voltage. Moreover, these strategies are applicable universally to any donor-acceptor interface. And we demonstrated such strategies in a bulk-heterojunction device which improved the power conversion efficiency from 3.5% up to 4.6%.

Efficient non-doped phosphorescent orange, blue and white organic light-emitting devices

Science.gov (United States)

Yin, Yongming; Yu, Jing; Cao, Hongtao; Zhang, Letian; Sun, Haizhu; Xie, Wenfa

2014-10-01

Efficient phosphorescent orange, blue and white organic light-emitting devices (OLEDs) with non-doped emissive layers were successfully fabricated. Conventional blue phosphorescent emitters bis [4,6-di-fluorophenyl]-pyridinato-N,C2'] picolinate (Firpic) and Bis(2,4-difluorophenylpyridinato) (Fir6) were adopted to fabricate non-doped blue OLEDs, which exhibited maximum current efficiency of 7.6 and 4.6 cd/A for Firpic and Fir6 based devices, respectively. Non-doped orange OLED was fabricated utilizing the newly reported phosphorescent material iridium (III) (pbi)2Ir(biq), of which manifested maximum current and power efficiency of 8.2 cd/A and 7.8 lm/W. The non-doped white OLEDs were achieved by simply combining Firpic or Fir6 with a 2-nm (pbi)2Ir(biq). The maximum current and power efficiency of the Firpic and (pbi)2Ir(biq) based white OLED were 14.8 cd/A and 17.9 lm/W.

High-efficiency terahertz polarization devices based on the dielectric metasurface

Science.gov (United States)

Zhou, Jian; Wang, JingJing; Guo, Kai; Shen, Fei; Zhou, Qingfeng; Zhiping yin; Guo, Zhongyi

2018-02-01

Metasurfaces are composed of the subwavelength structures, which can be used to manipulate the amplitude, phase, and polarization of incident electromagnetic waves efficiently. Here, we propose a novel type of dielectric metasurface based on crystal Si for realizing to manipulate the terahertz wave, in which by varying the geometric sizes of the Si micro-bricks, the transmitting phase of the terahertz wave can almost span over the entire 2π range for both of the x-polarization and y-polarization simultaneously, while keeping the similarly high-transmission amplitudes (over 90%). At the frequency of 1.0 THz, we have successfully designed a series of controllable THz devices, such as the polarization-dependent beam splitter, polarization-independent beam deflector and the focusing lenses based on the designed metasurfaces. Our designs are easy to fabricate and can be promising in developing high-efficiency THz functional devices.

Development of energy-saving devices for a full slow-speed ship through improving propulsion performance

Directory of Open Access Journals (Sweden)

Jung-Hun Kim

2015-03-01

Full Text Available Energy-saving devices for 317 K VLCC have been developed from a propulsion standpoint. Two ESD candidates were designed via computational tools. The first device WAFon composes of flow-control fins adapted for the ship wake to reduce the loss of rotational energy. The other is WAFon-D, which is a WAFon with a duct to obtain additional thrust and to distribute the inflow velocity on the propeller plane uniform. After selecting the candidates from the computed results, the speed performances were validated with model-tests. The hydrodynamic characteristics of the ESDs may be found in improved hull and propulsive efficiencies through increased wake fraction.

High-efficiency red electroluminescent device based on multishelled InP quantum dots.

Science.gov (United States)

Jo, Jung-Ho; Kim, Jong-Hoon; Lee, Ki-Heon; Han, Chang-Yeol; Jang, Eun-Pyo; Do, Young Rag; Yang, Heesun

2016-09-01

We report on the synthesis of highly fluorescent red-emitting InP quantum dots (QDs) and their application to the fabrication of a high-efficiency QD-light-emitting diode (QLED). The core/shell heterostructure of the QDs is elaborately tailored toward a multishelled structure with a composition-gradient ZnSeS intermediate shell and an outer ZnS shell. Using the resulting InP/ZnSeS/ZnS QDs as an emitting layer, all-solution-processible red InP QLEDs are fabricated with a hybrid multilayered device structure having an organic hole transport layer (HTL) and an inorganic ZnO nanoparticle electron transport layer. Two HTLs of poly(9-vinlycarbazole) or poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenyl-amine), whose hole mobilities are different by at least three orders of magnitude, are individually applied for QLED fabrication and such HTL-dependent device performances are compared. Our best red device displays exceptional figures of merit such as a maximum luminance of 2849  cd/m2, a current efficiency of 4.2  cd/A, and an external quantum efficiency of 2.5%.

Improving efficiency in stereology

DEFF Research Database (Denmark)

Keller, Kresten Krarup; Andersen, Ina Trolle; Andersen, Johnnie Bremholm

2013-01-01

of the study was to investigate the time efficiency of the proportionator and the autodisector on virtual slides compared with traditional methods in a practical application, namely the estimation of osteoclast numbers in paws from mice with experimental arthritis and control mice. Tissue slides were scanned......, a proportionator sampling and a systematic, uniform random sampling were simulated. We found that the proportionator was 50% to 90% more time efficient than systematic, uniform random sampling. The time efficiency of the autodisector on virtual slides was 60% to 100% better than the disector on tissue slides. We...... conclude that both the proportionator and the autodisector on virtual slides may improve efficiency of cell counting in stereology....

Enabling factors for the improvement of nitride-based LED efficiency

International Nuclear Information System (INIS)

Laubsch, Ansgar; Bergbauer, Werner; Sabathil, Matthias; Peter, Matthias; Meyer, Tobias; Bruederl, Georg; Linder, Norbert; Streubel, Klaus; Oberschmid, Raimund; Hahn, Berthold; Wagner, Joachim

2008-01-01

Recent progress in the epitaxial growth of LEDs with InGaN/GaN quantum-well heterostructures has led to a significant enhancement of output power. In this talk, we will discuss the mechanisms limiting the devices' internal efficiency and identify enabling factors for further improvements. We compare samples with different Indium content as well as different design of the active layer. Although heteroepitaxial growth of GaN on sapphire generates high defect densities, non-radiative defect-related Shockley-Read-Hall recombination does not seem to substantially limit the efficiency of standard InGaN/GaN LED structures. We rather discuss a supplemental Auger-like non-radiative path for carrier recombination that becomes dominant at quantum-well carrier densities typical for LED operation. Additionally, the piezo-field induced reduced overlap of electron and hole wavefunction in standard c-plane grown InGaN quantum wells reduces the radiative recombination rate

Progress of OLED devices with high efficiency at high luminance

Science.gov (United States)

Nguyen, Carmen; Ingram, Grayson; Lu, Zhenghong

2014-03-01

Organic light emitting diodes (OLEDs) have progressed significantly over the last two decades. For years, OLEDs have been promoted as the next generation technology for flat panel displays and solid-state lighting due to their potential for high energy efficiency and dynamic range of colors. Although high efficiency can readily be obtained at low brightness levels, a significant decline at high brightness is commonly observed. In this report, we will review various strategies for achieving highly efficient phosphorescent OLED devices at high luminance. Specifically, we will provide details regarding the performance and general working principles behind each strategy. We will conclude by looking at how some of these strategies can be combined to produce high efficiency white OLEDs at high brightness.

Realizing Efficient Energy Harvesting from Organic Photovoltaic Cells

Science.gov (United States)

Zou, Yunlong

Organic photovoltaic cells (OPVs) are emerging field of research in renewable energy. The development of OPVs in recent years has made this technology viable for many niche applications. In order to realize widespread application however, the power conversion efficiency requires further improvement. The efficiency of an OPV depends on the short-circuit current density (JSC), open-circuit voltage (VOC) and fill factor (FF). For state-of-the-art devices, JSC is mostly optimized with the application of novel low-bandgap materials and a bulk heterojunction device architecture (internal quantum efficiency approaching 100%). The remaining limiting factors are the low VOC and FF. This work focuses on overcoming these bottlenecks for improved efficiency. Temperature dependent measurements of device performance are used to examine both charge transfer and exciton ionization process in OPVs. The results permit an improved understanding of the intrinsic limit for VOC in various device architectures and provide insight on device operation. Efforts have also been directed at engineering device architecture for optimized FF, realizing a very high efficiency of 8% for vapor deposited small molecule OPVs. With collaborators, new molecules with tailored desired energy levels are being designed for further improvements in efficiency. A new type of hybrid organic-inorganic perovskite material is also included in this study. By addressing processing issues and anomalous hysteresis effects, a very high efficiency of 19.1% is achieved. Moving forward, topics including engineering film crystallinity, exploring tandem architectures and understanding degradation mechanisms will further push OPVs toward broad commercialization.

Common challenge in resource efficiency improvement

International Nuclear Information System (INIS)

La Motta, Sergio; Peronaci, Marcello

2015-01-01

Energy efficiency and technology improvements on their own will not achieve the Low Carbon Societies (LCS) goals. Thus, resource efficiency and a circular economy are keys to a low carbon society. Resource efficiency improvement potential has been analysed from the industrial and territorial management perspectives. Exploring synergies between LCS and the larger area of sustainable development and green economy, highlighting co-benefits and trade-offs, is of utmost importance to pave the way to a more equitable and largely participated low carbon transition.

Device Optimization and Transient Electroluminescence Studies of Organic light Emitting Devices

Energy Technology Data Exchange (ETDEWEB)

Lijuan Zou

2003-08-05

Organic light emitting devices (OLEDs) are among the most promising for flat panel display technologies. They are light, bright, flexible, and cost effective. And while they are emerging in commercial product, their low power efficiency and long-term degradation are still challenging. The aim of this work was to investigate their device physics and improve their performance. Violet and blue OLEDs were studied. The devices were prepared by thermal vapor deposition in high vacuum. The combinatorial method was employed in device preparation. Both continuous wave and transient electroluminescence (EL) were studied. A new efficient and intense UV-violet light emitting device was developed. At a current density of 10 mA/cm{sup 2}, the optimal radiance R could reach 0.38 mW/cm{sup 2}, and the quantum efficiency was 1.25%. using the delayed EL technique, electron mobilities in DPVBi and CBP were determined to be {approx} 10{sup -5} cm{sup 2}/Vs and {approx} 10{sup -4} cm{sup 2}/Vs, respectively. Overshoot effects in the transient El of blue light emitting devices were also observed and studied. This effect was attributed to the charge accumulation at the organic/organic and organic/cathode interfaces.

Device Optimization and Transient Electroluminescence Studies of Organic light Emitting Devices

International Nuclear Information System (INIS)

Lijuan Zou

2003-01-01

Organic light emitting devices (OLEDs) are among the most promising for flat panel display technologies. They are light, bright, flexible, and cost effective. And while they are emerging in commercial product, their low power efficiency and long-term degradation are still challenging. The aim of this work was to investigate their device physics and improve their performance. Violet and blue OLEDs were studied. The devices were prepared by thermal vapor deposition in high vacuum. The combinatorial method was employed in device preparation. Both continuous wave and transient electroluminescence (EL) were studied. A new efficient and intense UV-violet light emitting device was developed. At a current density of 10 mA/cm 2 , the optimal radiance R could reach 0.38 mW/cm 2 , and the quantum efficiency was 1.25%. using the delayed EL technique, electron mobilities in DPVBi and CBP were determined to be ∼ 10 -5 cm 2 /Vs and ∼ 10 -4 cm 2 /Vs, respectively. Overshoot effects in the transient El of blue light emitting devices were also observed and studied. This effect was attributed to the charge accumulation at the organic/organic and organic/cathode interfaces

Improvement in Device Performance and Reliability of Organic Light-Emitting Diodes through Deposition Rate Control

Directory of Open Access Journals (Sweden)

Shun-Wei Liu

2014-01-01

Full Text Available We demonstrated a fabrication technique to reduce the driving voltage, increase the current efficiency, and extend the operating lifetime of an organic light-emitting diode (OLED by simply controlling the deposition rate of bis(10-hydroxybenzo[h]qinolinato beryllium (Bebq2 used as the emitting layer and the electron-transport layer. In our optimized device, 55 nm of Bebq2 was first deposited at a faster deposition rate of 1.3 nm/s, followed by the deposition of a thin Bebq2 (5 nm layer at a slower rate of 0.03 nm/s. The Bebq2 layer with the faster deposition rate exhibited higher photoluminescence efficiency and was suitable for use in light emission. The thin Bebq2 layer with the slower deposition rate was used to modify the interface between the Bebq2 and cathode and hence improve the injection efficiency and lower the driving voltage. The operating lifetime of such a two-step deposition OLED was 1.92 and 4.6 times longer than that of devices with a single deposition rate, that is, 1.3 and 0.03 nm/s cases, respectively.

Manufacture of Daily Check Device and Efficiency Evaluation for Daily Q.A

International Nuclear Information System (INIS)

Kim, Chan Yong; Jae, Young Wan; Park, Heung Deuk; Lee, Jae Hee

2005-01-01

Daily Q.A is the important step which must be preceded in a radiation treatment. Specially, radiation output measurement and laser alignment, SSD indicator related to a patient set-up recurrence must be confirmed for a reasonable radiation treatment. Daily Q.A proceeds correctness and a prompt way, and needs an objective measurement basis. Manufacture of the device which can facilitate confirmation of output measurement and appliances check at one time was requested. Produced the phantom formal daily check device which can confirm a lot of appliances check (output measurement and laser alignment. field size, SSD indicator) with one time of set up at a time, and measurement observed a linear accelerator (4 machine) for four months and evaluated efficiency. We were able to confirm an laser alignment, field size, SSD indicator check at the same time, and out put measurement was possible with the same set up, so daily Q.A time was reduced, and we were able to confirm an objective basis about each item measurement. As a result of having measured for four months, output measurement within ±2%, and measured laser alignment, field size, SSD indicator in range within ±1 mm. We can enforce output measurement and appliances check conveniently, and time was reduced and was able to raise efficiency of business. We were able to bring a cost reduction by substitution expensive commercialized equipment. Further It is necessary to makes a product as strong and slight materials, and improve convenience of use.

Three-dimensional ordered titanium dioxide-zirconium dioxide film-based microfluidic device for efficient on-chip phosphopeptide enrichment.

Science.gov (United States)

Zhao, De; He, Zhongyuan; Wang, Gang; Wang, Hongzhi; Zhang, Qinghong; Li, Yaogang

2016-09-15

Microfluidic technology plays a significant role in separating biomolecules, because of its miniaturization, integration, and automation. Introducing micro/nanostructured functional materials can improve the properties of microfluidic devices, and extend their application. Inverse opal has a three-dimensional ordered net-like structure. It possesses a large surface area and exhibits good mass transport, making it a good candidate for bio-separation. This study exploits inverse opal titanium dioxide-zirconium dioxide films for on-chip phosphopeptide enrichment. Titanium dioxide-zirconium dioxide inverse opal film-based microfluidic devices were constructed from templates of 270-, 340-, and 370-nm-diameter poly(methylmethacrylate) spheres. The phosphopeptide enrichments of these devices were determined by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The device constructed from the 270-nm-diameter sphere template exhibited good comprehensive phosphopeptide enrichment, and was the best among these three devices. Because the size of opal template used in construction was the smallest, the inverse opal film therefore had the smallest pore sizes and the largest surface area. Enrichment by this device was also better than those of similar devices based on nanoparticle films and single component films. The titanium dioxide-zirconium dioxide inverse opal film-based device provides a promising approach for the efficient separation of various biomolecules. Copyright © 2016 Elsevier Inc. All rights reserved.

Red organic light emitting devices with reduced efficiency roll-off behavior by using hybrid fluorescent/phosphorescent emission structure

Energy Technology Data Exchange (ETDEWEB)

Zheng Tianhang; Choy, Wallace C.H., E-mail: chchoy@eee.hku.h

2010-11-01

Organic light emitting device (OLED) with a fluorescence-interlayer-phosphorescence emissive structure (FIP EML) is proposed to solve efficiency roll-off issue effectively. By doping fluorescent emitter of 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran (DCJTB) and phosphorescent emitter of tris(1-phenylisoquinolinolato-C2,N)iridium(III) (Ir(piq){sub 3}) into the different regions of emission zone to form FIP EML in red OLED, an improvement of more than 20% in luminance efficiency roll-off compared with that of typical phosphorescent OLED with single EML in 10-500 mA/cm{sup 2} range has been obtained. Detailed mechanisms have been studied. Such improvement should be attributed to the distinct roles of the two emitters, where DCJTB mainly used to influence the carrier transport leading to an improved balance of charge carriers while Ir(piq){sub 3} functions as the radiative decay sites for most generated excitons. Meanwhile, with the help of the formation of FIP EML, the redistribution of excitons in recombination zone, the suppression of non-radiative exciton quenching processes and the elimination of energy transfer loss also contribute to the enhancement of efficiency roll-off. The method proposed here may provide a route to develop efficient OLED for high luminance applications.

Tungsten oxides as interfacial layers for improved performance in hybrid optoelectronic devices

International Nuclear Information System (INIS)

Vasilopoulou, M.; Palilis, L.C.; Georgiadou, D.G.; Argitis, P.; Kennou, S.; Kostis, I.; Papadimitropoulos, G.; Stathopoulos, N.A.; Iliadis, A.A.; Konofaos, N.; Davazoglou, D.; Sygellou, L.

2011-01-01

Tungsten oxide (WO 3 ) films with thicknesses ranging from 30 to 100 nm were grown by Hot Filament Vapor Deposition (HFVD). Films were studied by X-Ray Photoemission Spectroscopy (XPS) and were found to be stoichiometric. The surface morphology of the films was characterized by Atomic Force Microscopy (AFM). Samples had a granular form with grains in the order of 100 nm. The surface roughness was found to increase with film thickness. HFVD WO 3 films were used as conducting interfacial layers in advanced hybrid organic-inorganic optoelectronic devices. Hybrid-Organic Light Emitting Diodes (Hy-OLEDs) and Organic Photovoltaics (Hy-OPVs) were fabricated with these films as anode and/or as cathode interfacial conducting layers. The Hy-OLEDs showed significantly higher current density and a lower turn-on voltage when a thin WO 3 layer was inserted at the anode/polymer interface, while when inserted at the cathode/polymer interface the device performance was found to deteriorate. The improvement was attributed to a more efficient hole injection and transport from the Fermi level of the anode to the Highest Occupied Molecular Orbital (HOMO) of a yellow emitting copolymer (YEP). On the other hand, the insertion of a thin WO 3 layer at the cathode/polymer interface of Hy-OPV devices based on a polythiophene-fullerene bulk-heterojunction blend photoactive layer resulted in an increase of the produced photogenerated current, more likely due to improved electron extraction at the Al cathode.

Improving broadcast performance of radio duty-cycled Internet-of-Things devices

NARCIS (Netherlands)

Guclu, S.S.; Özcelebi, T.; Lukkien, J.J.

2017-01-01

Asynchronous Radio Duty Cycling (ARDC) protocols can make embedded networked devices more energy efficient by keeping their radio off most of the time without a need for synchronization between devices. Some ARDC protocols can operate under 6LoWPAN adaptation layer in order to enable the vision of

Efficient, air-stable quantum dots light-emitting devices with MoO3 modifying the anode

International Nuclear Information System (INIS)

Meng, Xiangdong; Ji, Wenyu; Hua, Jie; Yu, Zhaoliang; Zhang, Yan; Li, Haibo; Zhao, Jialong

2013-01-01

In this work, we fabricated quantum dots light-emitting devices with hole-injection layer, molybdenum oxide (MoO 3 ) substituting for poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) which is hygroscopic and acidic and, therefore, a source of interface instability. A significant enhancement in luminance and current efficiency in MoO 3 -containing devices was observed. In addition, MoO 3 -containing devices were more stable in the air than those with PEDOT:PSS as the hole injection layer. The hole injection and transport of the devices were studied by the J–V characteristics of the hole-only devices. The excellent performance of the devices was principally a result of MoO 3 possessing lower injection barrier for the hole and better stability than PEDOT:PSS. -- Highlights: • We fabricated QD-LEDs with MoO 3 substituting for PEDOT:PSS as hole-injection layer. • A enhancement in luminance and efficiency in MoO 3 -containing device was observed. • The enhancement was originated from the stability and easy hole injection of MoO 3

Efficient fluorescent deep-blue and hybrid white emitting devices based on carbazole/benzimidazole compound

KAUST Repository

Yang, Xiaohui; Zheng, Shijun; Bottger, Rebecca; Chae, HyunSik; Tanaka, Takeshi; Li, Sheng; Mochizuki, Amane; Jabbour, Ghassan E.

2011-01-01

We report the synthesis, photophysics, and electrochemical characterization of carbazole/benzimidazole-based compound (Cz-2pbb) and efficient fluorescent deep-blue light emitting devices based on Cz-2pbb with the peak external quantum efficiency

Highly efficient phosphorescent blue and white organic light-emitting devices with simplified architectures

Energy Technology Data Exchange (ETDEWEB)

Chang, Chih-Hao, E-mail: chc@saturn.yzu.edu.tw [Department of Photonics Engineering, Yuan Ze University, Chung-Li, Taiwan 32003 (China); Ding, Yong-Shung; Hsieh, Po-Wei; Chang, Chien-Ping; Lin, Wei-Chieh [Department of Photonics Engineering, Yuan Ze University, Chung-Li, Taiwan 32003 (China); Chang, Hsin-Hua, E-mail: hhua3@mail.vnu.edu.tw [Department of Electro-Optical Engineering, Vanung University, Chung-Li, Taiwan 32061 (China)

2011-09-01

Blue phosphorescent organic light-emitting devices (PhOLEDs) with quantum efficiency close to the theoretical maximum were achieved by utilizing a double-layer architecture. Two wide-triplet-gap materials, 1,3-bis(9-carbazolyl)benzene and 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, were employed in the emitting and electron-transport layers respectively. The opposite carrier-transport characteristics of these two materials were leveraged to define the exciton formation zone and thus increase the probability of recombination. The efficiency at practical luminance (100 cd/m{sup 2}) was as high as 20.8%, 47.7 cd/A and 31.2 lm/W, respectively. Furthermore, based on the design concept of this simplified architecture, efficient warmish-white PhOLEDs were developed. Such two-component white organic light-emitting devices exhibited rather stable colors over a wide brightness range and yielded electroluminescence efficiencies of 15.3%, 33.3 cd/A, and 22.7 lm/W in the forward directions.

Highly efficient phosphorescent blue and white organic light-emitting devices with simplified architectures

International Nuclear Information System (INIS)

Chang, Chih-Hao; Ding, Yong-Shung; Hsieh, Po-Wei; Chang, Chien-Ping; Lin, Wei-Chieh; Chang, Hsin-Hua

2011-01-01

Blue phosphorescent organic light-emitting devices (PhOLEDs) with quantum efficiency close to the theoretical maximum were achieved by utilizing a double-layer architecture. Two wide-triplet-gap materials, 1,3-bis(9-carbazolyl)benzene and 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, were employed in the emitting and electron-transport layers respectively. The opposite carrier-transport characteristics of these two materials were leveraged to define the exciton formation zone and thus increase the probability of recombination. The efficiency at practical luminance (100 cd/m 2 ) was as high as 20.8%, 47.7 cd/A and 31.2 lm/W, respectively. Furthermore, based on the design concept of this simplified architecture, efficient warmish-white PhOLEDs were developed. Such two-component white organic light-emitting devices exhibited rather stable colors over a wide brightness range and yielded electroluminescence efficiencies of 15.3%, 33.3 cd/A, and 22.7 lm/W in the forward directions.

Demonstrating EnTracked a System for Energy-Efficient Position Tracking for Mobile Devices

DEFF Research Database (Denmark)

Kjærgaard, Mikkel Baun; Jensen, Jakob Langdal; Godsk, Torben

An important feature of a modern mobile device is that it can position itself. Not only for use on the device but also for remote applications that require tracking of the device. To be useful, such position tracking has to be energy-efficient to avoid having a major impact on the battery life...... of the mobile device. To address this challenge we have build a system named EnTracked that, based on the estimation and prediction of system conditions and mobility, schedules position updates to both minimize energy consumption and optimize robustness. In this demonstration we would like to show how...

Improving Security in Bring Your Own Device (BYOD) Environment by Controlling Access

OpenAIRE

Muhammad, M.A.; Zadeh, P.B.; Ayesh, Aladdin, 1972-

2017-01-01

With the rapid increase in smartphones and tablets, Bring Your Own Devices (BYOD) has simplified computing by introducing the use of personally owned devices. These devices can be utilised in accessing business enterprise contents and networks. The effectiveness of BYOD offers several business benefits like employee job satisfaction, increased job efficiency and flexibility. However, allowing employees to bring their own devices could lead to a plethora of security issues; like data theft, un...

Thermoelectric Energy Conversion: Materials, Devices, and Systems

International Nuclear Information System (INIS)

Chen, Gang

2015-01-01

This paper will present a discussion of challenges, progresses, and opportunities in thermoelectric energy conversion technology. We will start with an introduction to thermoelectric technology, followed by discussing advances in thermoelectric materials, devices, and systems. Thermoelectric energy conversion exploits the Seebeck effect to convert thermal energy into electricity, or the Peltier effect for heat pumping applications. Thermoelectric devices are scalable, capable of generating power from nano Watts to mega Watts. One key issue is to improve materials thermoelectric figure- of-merit that is linearly proportional to the Seebeck coefficient, the square of the electrical conductivity, and inversely proportional to the thermal conductivity. Improving the figure-of-merit requires good understanding of electron and phonon transport as their properties are often contradictory in trends. Over the past decade, excellent progresses have been made in the understanding of electron and phonon transport in thermoelectric materials, and in improving existing and identify new materials, especially by exploring nanoscale size effects. Taking materials to real world applications, however, faces more challenges in terms of materials stability, device fabrication, thermal management and system design. Progresses and lessons learnt from our effort in fabricating thermoelectric devices will be discussed. We have demonstrated device thermal-to-electrical energy conversion efficiency ∼10% and solar-thermoelectric generator efficiency at 4.6% without optical concentration of sunlight (Figure 1) and ∼8-9% efficiency with optical concentration. Great opportunities exist in advancing materials as well as in using existing materials for energy efficiency improvements and renewable energy utilization, as well as mobile applications. (paper)

Light extraction efficiency improvement in GaN-based blue light emitting diode with two-dimensional nano-cavity structure

International Nuclear Information System (INIS)

Cho, Joong-Yeon; Hong, Sung-Hoon; Byeon, Kyeong-Jae; Lee, Heon

2012-01-01

The light extraction efficiency of light emitting diode (LED) devices was improved by embedding nano-sized two-dimensional, air cavity photonic crystal (PC) structure on the indium tin oxide (ITO) layer of GaN-based LEDs. The embedded air cavity PC structure was fabricated using a reversal imprint lithography technique. The nano-cavity patterns had a width of 560 nm, a space of 240 nm and a height of 280 nm. According to current–voltage characterization, the electrical performance of the LED devices was not degraded by the fabrication process of air cavity PC structure. The optical output power of the LED device was increased by up to 10% at a drive current of 20 mA by forming the nano-cavity PC structure on the transparent electrode of the blue LED device, which was grown on a patterned sapphire substrate, to maximize the photon extraction. Since photons are scattered with cavities and are unaffected by the packaging process, which is the encapsulation of a LED device with epoxy resin, this enhancement in light extraction efficiency will not be decreased after the packaging process.

Highly efficient quantum dot-based photoconductive THz materials and devices

Science.gov (United States)

Rafailov, E. U.; Leyman, R.; Carnegie, D.; Bazieva, N.

2013-09-01

We demonstrate Terahertz (THz) signal sources based on photoconductive (PC) antenna devices comprising active layers of InAs semiconductor quantum dots (QDs) on GaAs. Antenna structures comprised of multiple active layers of InAs:GaAs PC materials are optically pumped using ultrashort pulses generated by a Ti:Sapphire laser and CW dualwavelength laser diodes. We also characterised THz output signals using a two-antenna coherent detection system. We discuss preliminary performance data from such InAs:GaAs THz devices which exhibit efficient emission of both pulsed and continuous wave (CW) THz signals and significant optical-to-THz conversion at both absorption wavelength ranges, <=850 nm and <=1300 nm.

Nanocellulose-based Translucent Diffuser for Optoelectronic Device Applications with Dramatic Improvement of Light Coupling.

Science.gov (United States)

Wu, Wei; Tassi, Nancy G; Zhu, Hongli; Fang, Zhiqiang; Hu, Liangbing

2015-12-09

Nanocellulose is a biogenerated and biorenewable organic material. Using a process based on 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)/NaClO/NaBr system, a highly translucent and light-diffusive film consisting of many layers of nanocellulose fibers and wood pulp microfibers was made. The film demonstrates a combination of large optical transmittance of ∼90% and tunable diffuse transmission of up to ∼78% across the visible and near-infrared spectra. The detailed characterizations of the film indicate the combination of high optical transmittance and haze is due to the film's large packing density and microstructured surface. The superior optical properties make the film a translucent light diffuser and applicable for improving the efficiencies of optoelectronic devices such as thin-film silicon solar cells and organic light-emitting devices.

Engineering Strain for Improved III-Nitride Optoelectronic Device Performance

Science.gov (United States)

Van Den Broeck, Dennis Marnix

Due to growing environmental and economic concerns, renewable energy generation and high-efficiency lighting are becoming even more important in the scientific community. III-Nitride devices have been essential in production of high-brightness light-emitting diodes (LEDs) and are now entering the photovoltaic (PV) realm as the technology advances. InGaN/GaN multiple quantum well LEDs emitting in the blue/green region have emerged as promising candidates for next-generation lighting technologies. Due to the large lattice mismatch between InN and GaN, large electric fields exist within the quantum well layers and result in low rates of radiative recombination, especially for the green spectral region. This is commonly referred to as the "green gap" and results in poor external quantum efficiencies for light-emitting diodes and laser diodes. In order to mitigate the compressive stress of InGaN QWs, a novel growth technique is developed in order to grown thick, strain-relaxed In yGa1-yN templates for 0.08 structure, "semibulk" InGaN templates were achieved with vastly superior crystal and optical properties than bulk InGaN films. These semibulk InGaN templates were then utilized as new templates for multiple quantum well active layers, effectively reducing the compressive strain in the InGaN wells due to the larger lattice constant of the InGaN template with respect to a GaN template. A zero-stress balance method was used in order to realize a strain-balanced multiple quantum well structure, which again showed improved optical characteristics when compared to fully-strain active regions. The semibulk InGaN template was then implemented into "strain-compensated" LED structures, where light emission was achieved with very little leakage current. Discussion of these strain-compensated devices compared to conventional LEDs is detailed.

Improvement of fuel sampling device for STACY and TRACY

International Nuclear Information System (INIS)

Hirose, Hideyuki; Sakuraba, Koichi; Onodera, Seiji

1998-05-01

STACY and TRACY, static and transient experiment facilities in NUCEF, use solution fuel. It is important to analyze accurately fuel composition (uranium enrichment, uranium concentration, nitric acid morality, amount of impurities, radioactivity of FP) for their safety operation and improvement of experimental accuracy. Both STACY and TRACY have the sampling devices to sample fuel solution for that purpose. The previous sampling devices of STACY and TRACY had been designed to dilute fuel sample with nitric acid. Its sampling mechanism could pour fuel sample into sampling vessel by a piston drive of nitric acid in the burette. It was, however, sometimes found that sample fuel solution was diluted by mixing with nitric acid in the burette. Therefore, the sampling mechanism was change into a fixed quantity pump drive which didn't use nitric acid. The authors confirmed that the performance of the new sampling device was improved by changing sampling mechanism. It was confirmed through the function test that the uncertainty in uranium concentration measurement using the improved sampling device was 0.14%, and less than the designed value of 0.2% (coefficient of variation). (author)

Single-crystal charge transfer interfaces for efficient photonic devices (Conference Presentation)

Science.gov (United States)

Alves, Helena; Pinto, Rui M.; Maçôas, Ermelinda M. S.; Baleizão, Carlos; Santos, Isabel C.

2016-09-01

Organic semiconductors have unique optical, mechanical and electronic properties that can be combined with customized chemical functionality. In the crystalline form, determinant features for electronic applications such as molecular purity, the charge mobility or the exciton diffusion length, reveal a superior performance when compared with materials in a more disordered form. Combining crystals of two different conjugated materials as even enable a new 2D electronic system. However, the use of organic single crystals in devices is still limited to a few applications, such as field-effect transistors. In 2013, we presented the first system composed of single-crystal charge transfer interfaces presenting photoconductivity behaviour. The system composed of rubrene and TCNQ has a responsivity reaching 1 A/W, corresponding to an external quantum efficiency of nearly 100%. A similar approach, with a hybrid structure of a PCBM film and rubrene single crystal also presents high responsivity and the possibility to extract excitons generated in acceptor materials. This strategy led to an extended action towards the near IR. By adequate material design and structural organisation of perylediimides, we demonstrate that is possible to improve exciton diffusion efficiency. More recently, we have successfully used the concept of charge transfer interfaces in phototransistors. These results open the possibility of using organic single-crystal interfaces in photonic applications.

Improving the efficiency of microwave devices with a double output cavity

International Nuclear Information System (INIS)

Eppley, K.R.; Herrmannsfeldt, W.B.; Lee, T.G.

1986-05-01

Double output cavities have been used experimentally to increase the efficiency of high-power klystrons. We have used particle-in-cell simulations with the 2 + 1/2 dimensional code MASK to optimize the design of double output cavities for the lasertron and the 50 MW klystron under development at SLAC. We discuss design considerations for double output cavities (e.g., optimum choice of voltages and phases, efficiency, wall interception, breakdown). We describe how one calculates the cavity impedance matrix from the gap voltages and phases. Simulation results are compared to experience with the 150 MW klystron

Flexible deep-ultraviolet light-emitting diodes for significant improvement of quantum efficiencies by external bending

KAUST Repository

Shervin, Shahab

2018-01-26

Deep ultraviolet (DUV) light at the wavelength range of 250‒280 nm (UVC spectrum) is essential for numerous applications such as sterilization, purification, sensing, and communication. III-nitride-based DUV light-emitting diodes (DUV LEDs), like other solid-state lighting sources, offer a great potential to replace the conventional gas-discharged lamps with short lifetimes and toxic-element-bearing nature. However, unlike visible LEDs, the DUV LEDs are still suffering from low quantum efficiencies (QEs) and low optical output powers. In this work, reported is a new route to improve QEs of AlGaN-based DUV LEDs using mechanical flexibility of recently developed bendable thin-film structures. Numerical studies show that electronic band structures of AlGaN heterostructures and resulting optical and electrical characteristics of the devices can be significantly modified by external bending through active control of piezoelectric polarization. Internal quantum efficiency (IQE) is enhanced higher than three times, when the DUV LEDs are moderately bent to induce in-plane compressive strain in the heterostructure. Furthermore, efficiency droop at high injection currents is mitigated and turn-on voltage of diodes decreases with the same bending condition. The concept of bendable DUV LEDs with a controlled external strain can provide a new path for high-output-power and high-efficiency devices.

Flexible deep-ultraviolet light-emitting diodes for significant improvement of quantum efficiencies by external bending

KAUST Repository

Shervin, Shahab; Oh, Seung Kyu; Park, Hyun Jung; Lee, Keon Hwa; Asadirad, Mojtaba; Kim, Seung Hwan; Kim, Jeomoh; Pouladi, Sara; Lee, Sung-Nam; Li, Xiaohang; Kwak, Joon-Seop; Ryou, Jae-Hyun

2018-01-01

Deep ultraviolet (DUV) light at the wavelength range of 250‒280 nm (UVC spectrum) is essential for numerous applications such as sterilization, purification, sensing, and communication. III-nitride-based DUV light-emitting diodes (DUV LEDs), like other solid-state lighting sources, offer a great potential to replace the conventional gas-discharged lamps with short lifetimes and toxic-element-bearing nature. However, unlike visible LEDs, the DUV LEDs are still suffering from low quantum efficiencies (QEs) and low optical output powers. In this work, reported is a new route to improve QEs of AlGaN-based DUV LEDs using mechanical flexibility of recently developed bendable thin-film structures. Numerical studies show that electronic band structures of AlGaN heterostructures and resulting optical and electrical characteristics of the devices can be significantly modified by external bending through active control of piezoelectric polarization. Internal quantum efficiency (IQE) is enhanced higher than three times, when the DUV LEDs are moderately bent to induce in-plane compressive strain in the heterostructure. Furthermore, efficiency droop at high injection currents is mitigated and turn-on voltage of diodes decreases with the same bending condition. The concept of bendable DUV LEDs with a controlled external strain can provide a new path for high-output-power and high-efficiency devices.

Thermal analysis and improvement of cascode GaN device package for totem-pole bridgeless PFC rectifier

International Nuclear Information System (INIS)

She, Shuojie; Zhang, Wenli; Liu, Zhengyang; Lee, Fred C.; Huang, Xiucheng; Du, Weijing; Li, Qiang

2015-01-01

The totem-pole bridgeless power factor correction (PFC) rectifier has a simpler topology and higher efficiency than other boost-type bridgeless PFC rectifiers. Its promising performance is enabled by using high-voltage gallium nitride (GaN) high-electron-mobility transistors, which have considerably better figures of merit (e.g., lower reverse recovery charges and less switching losses) than the state-of-the-art silicon metal-oxide-semiconductor field-effect transistors. Cascode GaN devices in traditional packages, i.e., the TO-220 and power quad flat no-lead, are used in the totem-pole PFC boost rectifier. But the parasitic inductances induced by the traditional packages not only significantly deteriorate the switching characteristics of the discrete GaN device but also adversely affect the performance of the built PFC rectifier. A new stack-die packaging structure with an embedded capacitor has been introduced and proven to be efficient in reducing parasitic ringing at the turn-off transition and achieving true zero-voltage-switching turn-on. However, the thermal dissipation capability of the device packaged in this configuration becomes a limitation on further pushing the operating frequency and the output current level for high-efficiency power conversion. This paper focuses on the thermal analysis of the cascode GaN devices in different packages and the GaN-based multichip module used in a two-phase totem-pole bridgeless PFC boost rectifier. A series of thermal models are built based on the actual structures and materials of the packaged devices to evaluate their thermal performance. Finite element analysis (FEA) simulation results of the cascode GaN device in a flip-chip format demonstrate the possibility of increasing the device switching speed while maintaining the peak temperature of the device below 125 °C. Thermal analysis of the GaN-based power module in a very similar structure is also conducted using the FEA method. Experimental data measured using

Frontier technologies to improve efficiency

International Nuclear Information System (INIS)

Kalhammer, F.R.

1992-01-01

The author discusses conservation technology to improve the efficiency of energy production. Although coal is seen as the largest source of fuel for producing electricity until the year 2040, the heating value of coal is expected to be increased by using Integrated Gasification Combined Cycle (IGCC) technology. Use of fuel cells to produce electricity will be a viable option only if costs can be reduced to make the technology competitive. By coupling IGCC with fuel cells it may be possible to increase total conversion efficiency of coal to electricity at 50%. Photovoltaics technology is more likely to be used in developing countries. Electric utilities target power electronics, lighting fixtures, heat pumps, plasma processing, freeze concentration and application of superconductivity as electricity end use technologies that have the most potential for efficiency improvement. The impact of these technologies in coping with the greenhouse effect was not addressed

GATE: Improving the computational efficiency

International Nuclear Information System (INIS)

Staelens, S.; De Beenhouwer, J.; Kruecker, D.; Maigne, L.; Rannou, F.; Ferrer, L.; D'Asseler, Y.; Buvat, I.; Lemahieu, I.

2006-01-01

GATE is a software dedicated to Monte Carlo simulations in Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET). An important disadvantage of those simulations is the fundamental burden of computation time. This manuscript describes three different techniques in order to improve the efficiency of those simulations. Firstly, the implementation of variance reduction techniques (VRTs), more specifically the incorporation of geometrical importance sampling, is discussed. After this, the newly designed cluster version of the GATE software is described. The experiments have shown that GATE simulations scale very well on a cluster of homogeneous computers. Finally, an elaboration on the deployment of GATE on the Enabling Grids for E-Science in Europe (EGEE) grid will conclude the description of efficiency enhancement efforts. The three aforementioned methods improve the efficiency of GATE to a large extent and make realistic patient-specific overnight Monte Carlo simulations achievable

Quasi-Resonant Absorption for Quantum Efficiency Improvement in Detectors

Data.gov (United States)

National Aeronautics and Space Administration — Quasi-resonant absorption has been demonstrated to enhance the quantum efficiency of devices across the spectrum, but specifically it is a challenge in the UV...

Improved light extraction from white organic light-emitting devices using a binary random phase array

International Nuclear Information System (INIS)

Inada, Yasuhisa; Nishiwaki, Seiji; Hirasawa, Taku; Nakamura, Yoshitaka; Hashiya, Akira; Wakabayashi, Shin-ichi; Suzuki, Masa-aki; Matsuzaki, Jumpei

2014-01-01

We have developed a binary random phase array (BRPA) to improve the light extraction performance of white organic light-emitting devices (WOLEDs). We demonstrated that the scattering of incoming light can be controlled by employing diffraction optics to modify the structural parameters of the BRPA. Applying a BRPA to the substrate of the WOLED leads to enhanced extraction efficiency and suppression of angle-dependent color changes. Our systematic study clarifies the effect of scattering on the light extraction of WOLEDs

Improved light extraction from white organic light-emitting devices using a binary random phase array

Energy Technology Data Exchange (ETDEWEB)

Inada, Yasuhisa, E-mail: inada.yasuhisa@jp.panasonic.com; Nishiwaki, Seiji; Hirasawa, Taku; Nakamura, Yoshitaka; Hashiya, Akira; Wakabayashi, Shin-ichi; Suzuki, Masa-aki [R and D Division, Panasonic Corporation, 1006 Kadoma, Kadoma City, Osaka 571-8501 (Japan); Matsuzaki, Jumpei [Device Development Center, Eco Solutions Company, Panasonic Corporation, 1048 Kadoma, Osaka 571-8686 Japan (Japan)

2014-02-10

We have developed a binary random phase array (BRPA) to improve the light extraction performance of white organic light-emitting devices (WOLEDs). We demonstrated that the scattering of incoming light can be controlled by employing diffraction optics to modify the structural parameters of the BRPA. Applying a BRPA to the substrate of the WOLED leads to enhanced extraction efficiency and suppression of angle-dependent color changes. Our systematic study clarifies the effect of scattering on the light extraction of WOLEDs.

Superefficient Refrigerators: Opportunities and Challenges for Efficiency Improvement Globally

Energy Technology Data Exchange (ETDEWEB)

Shah, Nihar; Park, Won Young; Bojda, Nicholas; McNeil, Michael A.

2014-08-01

As an energy-intensive mainstream product, residential refrigerators present a significant opportunity to reduce electricity consumption through energy efficiency improvements. Refrigerators expend a considerable amount of electricity during normal use, typically consuming between 100 to 1,000 kWh of electricity per annum. This paper presents the results of a technical analysis done for refrigerators in support of the Super-efficient Equipment and Appliance Deployment (SEAD) initiative. Beginning from a base case representative of the average unit sold in India, we analyze efficiency improvement options and their corresponding costs to build a cost-versus-efficiency relationship. We then consider design improvement options that are known to be the most cost effective and that can improve efficiency given current design configurations. We also analyze and present additional super-efficient options, such as vacuum-insulated panels. We estimate the cost of conserved electricity for the various options, allowing flexible program design for market transformation programs toward higher efficiency. We estimate ~;;160TWh/year of energy savings are cost effective in 2030, indicating significant potential for efficiency improvement in refrigerators in SEAD economies and China.

Production, characterization and stability of organic solar cell devices

Energy Technology Data Exchange (ETDEWEB)

Gevorgyan, S A

2010-01-15

Despite the fact that the field of organic photovoltaics (OPVs) is in a rapid progress, organic solar cells continue taking backstage roll in the growing markets of various solar technologies. The main challenge of the field is to develop devices that would possess all the optimal properties required for efficient, stable and cheap solar cells, i.e. devices that can deliver high photoconversion efficiencies and long lifetimes and can be efficiently produced in large scales using roll-to-roll coating technologies. This dissertation is primarily devoted to the issues of photoconversion efficiency and device lifetimes. In particular, descriptions of some practical approaches for different device designs and processing of active layer for typical small scale OPV devices were presented. The emphasis was put on some optimizing techniques for processing of active layer that can significantly improve the device photoconversion efficiency. The techniques were further applied for manufacturing and characterization of solar cell devices based on various materials. In particular, a number of thermocleavable polymers were studied and devices based on such materials were produced and characterized. The applicability of such materials in photovoltaic devices was shown and further challenges were discussed. Another task of this work was to manufacture and study inverted device structures and compare their properties with normal structure based devices. Device based on both structure were successfully produced with same level of performance in terms of photoconversion efficiency, yet with totally different stability performance. As another task, metal oxides, such as MoO{sub 3} or V{sub 2}O{sub 5} were studied in solar cell devices as buffer layers instead of PEDOT:PSS. Although the device efficiencies obtained with metal oxides were inferior to PEDOT based device, it was shown that such materials can possibly improve the device efficiency if the processing of the layers is

Si Hybrid Solar Cells with 13% Efficiency via Concurrent Improvement in Optical and Electrical Properties by Employing Graphene Quantum Dots

KAUST Repository

Tsai, Meng Lin

2015-12-18

By employing graphene quantum dots (GQDs) in PEDOT:PSS, we have achieved an efficiency of 13.22% in Si/PEDOT:PSS hybrid solar cells. The efficiency enhancement is based on concurrent improvement in optical and electrical properties by the photon downconversion process and the improved conductivity of PEDOT:PSS via appropriate incorporation of GQDs. After introducing GQDs into PEDOT:PSS, the short circuit current and the fill factor of rear-contact optimized hybrid cells are increased from 32.11 to 36.26 mA/cm and 62.85% to 63.87%, respectively. The organic-inorganic hybrid solar cell obtained herein holds the promise for developing photon-managing, low-cost, and highly efficient photovoltaic devices.

Si Hybrid Solar Cells with 13% Efficiency via Concurrent Improvement in Optical and Electrical Properties by Employing Graphene Quantum Dots

KAUST Repository

Tsai, Meng Lin; Wei, Wan-Rou; Tang, Libin; Chang, Hung Chih; Tai, Shih Hsiang; Yang, Po Kang; Lau, Shu Ping; Chen, Lih Juann; He, Jr-Hau

2015-01-01

By employing graphene quantum dots (GQDs) in PEDOT:PSS, we have achieved an efficiency of 13.22% in Si/PEDOT:PSS hybrid solar cells. The efficiency enhancement is based on concurrent improvement in optical and electrical properties by the photon downconversion process and the improved conductivity of PEDOT:PSS via appropriate incorporation of GQDs. After introducing GQDs into PEDOT:PSS, the short circuit current and the fill factor of rear-contact optimized hybrid cells are increased from 32.11 to 36.26 mA/cm and 62.85% to 63.87%, respectively. The organic-inorganic hybrid solar cell obtained herein holds the promise for developing photon-managing, low-cost, and highly efficient photovoltaic devices.

Improved efficiency of NiOx-based p-i-n perovskite solar cells by using PTEG-1 as electron transport layer

Science.gov (United States)

Groeneveld, Bart G. H. M.; Najafi, Mehrdad; Steensma, Bauke; Adjokatse, Sampson; Fang, Hong-Hua; Jahani, Fatemeh; Qiu, Li; ten Brink, Gert H.; Hummelen, Jan C.; Loi, Maria Antonietta

2017-07-01

We present efficient p-i-n type perovskite solar cells using NiOx as the hole transport layer and a fulleropyrrolidine with a triethylene glycol monoethyl ether side chain (PTEG-1) as electron transport layer. This electron transport layer leads to higher power conversion efficiencies compared to perovskite solar cells with PCBM (phenyl-C61-butyric acid methyl ester). The improved performance of PTEG-1 devices is attributed to the reduced trap-assisted recombination and improved charge extraction in these solar cells, as determined by light intensity dependence and photoluminescence measurements. Through optimization of the hole and electron transport layers, the power conversion efficiency of the NiOx/perovskite/PTEG-1 solar cells was increased up to 16.1%.

Improved power efficiency of blue fluorescent organic light-emitting diode with intermixed host structure

Energy Technology Data Exchange (ETDEWEB)

Yue, Shouzhen; Zhang, Shiming; Zhang, Zhensong; Wu, Yukun; Wang, Peng; Guo, Runda; Chen, Yu; Qu, Dalong; Wu, Qingyang; Zhao, Yi, E-mail: yizhao@jlu.edu.cn; Liu, Shiyong

2013-11-15

High power efficiency (PE) p-bis(p-N,N-diphenyl-aminostyryl)benzene (DSA-ph) based fluorescent blue organic light-emitting diode (OLED) is demonstrated by utilizing intermixed host (IH) structure. The PE outperforms those devices based on single host (SH), mixed host (MH), and double emitting layers (DELs). By further optimizing the intermixed layer, peak PE of the IH device is increased up to 8.7 lm/W (1.7 times higher than conventional SH device), which is the highest value among the DSA-ph based blue device reported so far. -- Highlights: • DSA-ph based blue fluorescent OLEDs are fabricated. • The intermixed host structure is first introduced into the blue devices. • Blue device with the highest power efficiency based on DSA-ph is obtained.

Enhanced quantum efficiency in blue-emitting polymer/dielectric nanolayer nanocomposite light-emitting devices

International Nuclear Information System (INIS)

Park, Jong Hyeok; Lim, Yong Taik; Park, O Ok; Yu, Jae-Woong; Kim, Jai Kyeong; Kim, Young Chul

2004-01-01

Light-emitting devices based on environmentally stable, blue-emitting polymer/dielectric nanolayer nanocomposites were fabricated by blending poly(di-octylfluorene) (PDOF) with organo-clay. By reducing the excimer formation that leads to long wavelength tails, the photoluminescence (PL) and electroluminescence (EL) color purity of the device was enhanced. When a conjugated polymer/dielectric nanolayer nanocomposite is applied to an EL device, we expect an electronic structure similar to the well-known quantum well in small nanodomains. The ratio of PDOF/organo-clay was regulated from 2:1 to 0.5:1 (w/w). The light-emitting device of 0.5:1 (w/w) blend demonstrated the highest quantum efficiency (QE), 0.72% (ph/el), which is ∼500 times higher value compared with that of the pure PDOF layer device. However, the driving voltage of the nanocomposite devices tended to increase with increasing organo-clay content

Use-related risk analysis for medical devices based on improved FMEA.

Science.gov (United States)

Liu, Long; Shuai, Ma; Wang, Zhu; Li, Ping

2012-01-01

In order to effectively analyze and control use-related risk of medical devices, quantitative methodologies must be applied. Failure Mode and Effects Analysis (FMEA) is a proactive technique for error detection and risk reduction. In this article, an improved FMEA based on Fuzzy Mathematics and Grey Relational Theory is developed to better carry out user-related risk analysis for medical devices. As an example, the analysis process using this improved FMEA method for a certain medical device (C-arm X-ray machine) is described.

Loss Model and Efficiency Analysis of Tram Auxiliary Converter Based on a SiC Device

Directory of Open Access Journals (Sweden)

Hao Liu

2017-12-01

Full Text Available Currently, the auxiliary converter in the auxiliary power supply system of a modern tram adopts Si IGBT as its switching device and with the 1700 V/225 A SiC MOSFET module commercially available from Cree, an auxiliary converter using all SiC devices is now possible. A SiC auxiliary converter prototype is developed during this study. The author(s derive the loss calculation formula of the SiC auxiliary converter according to the system topology and principle and each part loss in this system can be calculated based on the device datasheet. Then, the static and dynamic characteristics of the SiC MOSFET module used in the system are tested, which aids in fully understanding the performance of the SiC devices and provides data support for the establishment of the PLECS loss simulation model. Additionally, according to the actual circuit parameters, the PLECS loss simulation model is set up. This simulation model can simulate the actual operating conditions of the auxiliary converter system and calculate the loss of each switching device. Finally, the loss of the SiC auxiliary converter prototype is measured and through comparison it is found that the loss calculation theory and PLECS loss simulation model is valuable. Furthermore, the thermal images of the system can prove the conclusion about loss distribution to some extent. Moreover, these two methods have the advantages of less variables and fast calculation for high power applications. The loss models may aid in optimizing the switching frequency and improving the efficiency of the system.

High-power waveguide resonator second harmonic device with external conversion efficiency up to 75%

Science.gov (United States)

Stefszky, M.; Ricken, R.; Eigner, C.; Quiring, V.; Herrmann, H.; Silberhorn, C.

2018-06-01

We report on a highly efficient waveguide resonator device for the production of 775 nm light using a titanium indiffused LiNbO3 waveguide resonator. When scanning the resonance, the device produces up to 110 mW of second harmonic power with 140 mW incident on the device—an external conversion efficiency of 75%. The cavity length is also locked, using a Pound–Drever–Hall type locking scheme, involving feedback to either the cavity temperature or the laser frequency. With laser frequency feedback, a stable output power of approximately 28 mW from a 52 mW pump is seen over one hour.

An Efficient and Secure m-IPS Scheme of Mobile Devices for Human-Centric Computing

Directory of Open Access Journals (Sweden)

Young-Sik Jeong

2014-01-01

Full Text Available Recent rapid developments in wireless and mobile IT technologies have led to their application in many real-life areas, such as disasters, home networks, mobile social networks, medical services, industry, schools, and the military. Business/work environments have become wire/wireless, integrated with wireless networks. Although the increase in the use of mobile devices that can use wireless networks increases work efficiency and provides greater convenience, wireless access to networks represents a security threat. Currently, wireless intrusion prevention systems (IPSs are used to prevent wireless security threats. However, these are not an ideal security measure for businesses that utilize mobile devices because they do not take account of temporal-spatial and role information factors. Therefore, in this paper, an efficient and secure mobile-IPS (m-IPS is proposed for businesses utilizing mobile devices in mobile environments for human-centric computing. The m-IPS system incorporates temporal-spatial awareness in human-centric computing with various mobile devices and checks users’ temporal spatial information, profiles, and role information to provide precise access control. And it also can extend application of m-IPS to the Internet of things (IoT, which is one of the important advanced technologies for supporting human-centric computing environment completely, for real ubiquitous field with mobile devices.

An efficient enzyme-powered micromotor device fabricated by cyclic alternate hybridization assembly for DNA detection.

Science.gov (United States)

Fu, Shizhe; Zhang, Xueqing; Xie, Yuzhe; Wu, Jie; Ju, Huangxian

2017-07-06

An efficient enzyme-powered micromotor device was fabricated by assembling multiple layers of catalase on the inner surface of a poly(3,4-ethylenedioxythiophene and sodium 4-styrenesulfonate)/Au microtube (PEDOT-PSS/Au). The catalase assembly was achieved by programmed DNA hybridization, which was performed by immobilizing a designed sandwich DNA structure as the sensing unit on the PEDOT-PSS/Au, and then alternately hybridizing with two assisting DNA to bind the enzyme for efficient motor motion. The micromotor device showed unique features of good reproducibility, stability and motion performance. Under optimal conditions, it showed a speed of 420 μm s -1 in 2% H 2 O 2 and even 51 μm s -1 in 0.25% H 2 O 2 . In the presence of target DNA, the sensing unit hybridized with target DNA to release the multi-layer DNA as well as the multi-catalase, resulting in a decrease of the motion speed. By using the speed as a signal, the micromotor device could detect DNA from 10 nM to 1 μM. The proposed micromotor device along with the cyclic alternate DNA hybridization assembly technique provided a new path to fabricate efficient and versatile micromotors, which would be an exceptional tool for rapid and simple detection of biomolecules.

A new device for vein localization and effect of application of disinfectant spray on its efficiency

Directory of Open Access Journals (Sweden)

Dreyer Jan

2017-09-01

Full Text Available A functional device was developed to immediately show the localization of veins by detecting a temperature increase on the skin directly above them. Our new idea, compared to other developments, is the comparison of temperatures between a small, ideally punctiform, skin area, and a larger circularly surrounding area. This is realized by two infrared temperature sensors, one with a small field of view, and the other one with a larger field of view. The position of the vein is indicated by two laser modules, which beams cross in one spot, when the device is held in a defined distance to the skin. If the device is held over a vein, the laser spot lightens up. The device was tested in ten study participants. Cooling of the skin by disinfectant spray prior to the measurements increases the temperature gradient and thereby improves the efficiency of the device. Temperature profiles of four skin areas of each study participant were measured before and one minute after application of disinfectant spray. After application of disinfectant spray, a temperature difference of more than 0.3 K between a measuring point above a vein and points 15 mm next to this could be found in 36 out of 40 measurements (90%, compared to 26 out of 40 (65% before disinfection. The mean temperature gradient could be increased from 0.476 K to 1.03 K (p < 0.001.

Digital lingual orthodontics and temporary anchorage devices for efficient biomechanics

Directory of Open Access Journals (Sweden)

Pravin Shetty

2016-01-01

Full Text Available Adult patients seeking orthodontic treatment at all times present with an esthetic demand even during treatment. The lingual orthodontics, apart from its esthetic values, also presents several other advantages. Currently, it has become a complete system in itself, starting from an accurate diagnosis, treatment protocol, and laboratory procedure to placement of the appliance in the patient′s mouth. With the advent of computer-aided design/computer-aided manufacturing system, the lingual orthodontics is more evolved and made ease operators in respect to more efficient mechanics and reduced archwire adjustments. The present article presents two cases to show the efficiency of lingual orthodontics with temporary anchorage devices and anterior retraction hook.

In Situ Preparation of Metal Halide Perovskite Nanocrystal Thin Films for Improved Light-Emitting Devices.

Science.gov (United States)

Zhao, Lianfeng; Yeh, Yao-Wen; Tran, Nhu L; Wu, Fan; Xiao, Zhengguo; Kerner, Ross A; Lin, YunHui L; Scholes, Gregory D; Yao, Nan; Rand, Barry P

2017-04-25

Hybrid organic-inorganic halide perovskite semiconductors are attractive candidates for optoelectronic applications, such as photovoltaics, light-emitting diodes, and lasers. Perovskite nanocrystals are of particular interest, where electrons and holes can be confined spatially, promoting radiative recombination. However, nanocrystalline films based on traditional colloidal nanocrystal synthesis strategies suffer from the use of long insulating ligands, low colloidal nanocrystal concentration, and significant aggregation during film formation. Here, we demonstrate a facile method for preparing perovskite nanocrystal films in situ and that the electroluminescence of light-emitting devices can be enhanced up to 40-fold through this nanocrystal film formation strategy. Briefly, the method involves the use of bulky organoammonium halides as additives to confine crystal growth of perovskites during film formation, achieving CH 3 NH 3 PbI 3 and CH 3 NH 3 PbBr 3 perovskite nanocrystals with an average crystal size of 5.4 ± 0.8 nm and 6.4 ± 1.3 nm, respectively, as confirmed through transmission electron microscopy measurements. Additive-confined perovskite nanocrystals show significantly improved photoluminescence quantum yield and decay lifetime. Finally, we demonstrate highly efficient CH 3 NH 3 PbI 3 red/near-infrared LEDs and CH 3 NH 3 PbBr 3 green LEDs based on this strategy, achieving an external quantum efficiency of 7.9% and 7.0%, respectively, which represent a 40-fold and 23-fold improvement over control devices fabricated without the additives.

Influence of the ambient temperature on the cooling efficiency of the high performance cooling device with thermosiphon effect

Science.gov (United States)

Nemec, Patrik; Malcho, Milan

2018-06-01

This work deal with experimental measurement and calculation cooling efficiency of the cooling device working with a heat pipe technology. The referred device in the article is cooling device capable transfer high heat fluxes from electric elements to the surrounding. The work contain description, working principle and construction of cooling device. The main factor affected the dissipation of high heat flux from electronic elements through the cooling device to the surrounding is condenser construction, its capacity and option of heat removal. Experimental part describe the measuring method cooling efficiency of the cooling device depending on ambient temperature in range -20 to 40°C and at heat load of electronic components 750 W. Measured results are compared with results calculation based on physical phenomena of boiling, condensation and natural convection heat transfer.

Reliability improvement in GaN HEMT power device using a field plate approach

Science.gov (United States)

Wu, Wen-Hao; Lin, Yueh-Chin; Chin, Ping-Chieh; Hsu, Chia-Chieh; Lee, Jin-Hwa; Liu, Shih-Chien; Maa, Jer-shen; Iwai, Hiroshi; Chang, Edward Yi; Hsu, Heng-Tung

2017-07-01

This study investigates the effect of implementing a field plate on a GaN high-electron-mobility transistor (HEMT) to improve power device reliability. The results indicate that the field plate structure reduces the peak electrical field and interface traps in the device, resulting in higher breakdown voltage, lower leakage current, smaller current collapse, and better threshold voltage control. Furthermore, after high voltage stress, steady dynamic on-resistance and gate capacitance degradation improvement were observed for the device with the field plate. This demonstrates that GaN device reliability can be improved by using the field plate approach.

Fundamental and future prospects of printed ambipolar fluorene-type polymer light-emitting transistors for improved external quantum efficiency, mobility, and emission pattern

Science.gov (United States)

Kajii, Hirotake

2018-05-01

In this review, we focus on the improved external quantum efficiency, field-effect mobility, and emission pattern of top-gate-type polymer light-emitting transistors (PLETs) based on ambipolar fluorene-type polymers. A low-temperature, high-efficiency, printable red phosphorescent PLET based on poly(alkylfluorene) with modified alkyl side chains fabricated by a film transfer process is demonstrated. Device fabrication based on oriented films leads to an improved EL intensity owing to the increase in field-effect mobility. There are three factors that affect the transport of carriers, i.e., the energy level, threshold voltage, and mobility of each layer for heterostructure PLETs, which result in various emission patterns such as the line-shaped, multicolor and in-plane emission pattern in the full-channel area between source and drain electrodes. Fundamentals and future prospects in heterostructure devices are discussed and reviewed.

High efficiency solid-state sensitized heterojunction photovoltaic device

KAUST Repository

Wang, Mingkui

2010-06-01

The high molar extinction coefficient heteroleptic ruthenium dye, NaRu(4,4′-bis(5-(hexylthio)thiophen-2-yl)-2,2′-bipyridine) (4-carboxylic acid-4′-carboxylate-2,2′-bipyridine) (NCS) 2, exhibits certified 5% electric power conversion efficiency at AM 1.5 solar irradiation (100 mW cm-2) in a solid-state dye-sensitized solar cell using 2,2′,7,7′-tetrakis-(N,N-di-pmethoxyphenylamine)-9, 9′-spirobifluorene (spiro-MeOTAD) as the organic hole-transporting material. This demonstration elucidates a class of photovoltaic devices with potential for low-cost power generation. © 2010 Elsevier Ltd. All rights reserved.

High efficiency solid-state sensitized heterojunction photovoltaic device

KAUST Repository

Wang, Mingkui; Liu, Jingyuan; Cevey-Ha, Ngoc-Le; Moon, Soo-Jin; Liska, Paul; Humphry-Baker, Robin; Moser, Jacques-E.; Grä tzel, Carole; Wang, Peng; Zakeeruddin, Shaik M.

2010-01-01

The high molar extinction coefficient heteroleptic ruthenium dye, NaRu(4,4′-bis(5-(hexylthio)thiophen-2-yl)-2,2′-bipyridine) (4-carboxylic acid-4′-carboxylate-2,2′-bipyridine) (NCS) 2, exhibits certified 5% electric power conversion efficiency at AM 1.5 solar irradiation (100 mW cm-2) in a solid-state dye-sensitized solar cell using 2,2′,7,7′-tetrakis-(N,N-di-pmethoxyphenylamine)-9, 9′-spirobifluorene (spiro-MeOTAD) as the organic hole-transporting material. This demonstration elucidates a class of photovoltaic devices with potential for low-cost power generation. © 2010 Elsevier Ltd. All rights reserved.

Improved Light Extraction Efficiency by Photonic Crystal Arrays on Transparent Contact Layer Using Focused Ion Beams

International Nuclear Information System (INIS)

Wu, G.M.; Tsai, B.H.; Kung, S.F.; Wu, C.F.

2011-01-01

Nitride-based thin-film materials have become increasingly important for the high brightness light-emitting diode applications. The improvements in light extraction and lower power consumption are highly desired. Although the internal quantum efficiency of GaN-based LED has been relatively high, only a small fraction of light can be extracted. In this study, a new design of two-dimensional photonic crystal array has been prepared on the top transparent contact layer of indium-tin oxide film to improve the light extraction efficiency using focused ion beam. The acceleration voltage of the Ga dual-beam nanotechnology system SMI 3050 was 30 kV and the ion beam current was 100 pA. The cylindrical air holes had the diameter of 150 nm and depth of 100 nm. The micro photoluminescence analysis results showed that the light output intensity could be 1.5 times of that of the non-patterned control sample. In addition, the structural damage from the focused ion beam drilling of GaN step could be eliminated. The excellent I-V characteristics have been maintained, and the external light extraction efficiency would be still improved for the LED devices. (author)

Multi variable control of a switched ignition device: efficiency improvement under various constraints; Commande multivariable d`un moteur a allumage commande: Amelioration du rendement sous differentes contraintes

Energy Technology Data Exchange (ETDEWEB)

Chaumerliac, V

1995-03-09

Spark-ignition engine control needs substantial improvement for various reasons: a non-linear and multivariable process, the strictness of anti-pollution constraints, the necessity of fuel economy, the variable running conditions, the aging, the reliability and the cost. The improvement of engine efficiency will be involved in this context and with the pollution constraints. This work develops a system approach and its philosophy is based on a suitable description of the main dynamics. A compartmentalized model of a spark-ignition engine and the dynamic of the vehicle is presented. The aim of this modeling is to have a good representativeness in transients and to describe the behavior of the outputs useful for control. The multivariable control is split in two independent systems. The first one controls the spark advance control to obtain the maximum torque. The second one controls the throttle and the electronic fuel injection device to have lower pollutant emissions. The spark advance closed loop control uses information measured with either a cylinder pressure sensor or a torque sensor. These studies have achieved to an adaptive tuning on engine bench. A new actuator, the electronic throttle control, can provide a higher degree of precision for the fuel/air ratio regulation system, particularly during fast accelerations and decelerations. An intake manifold pressure control is developed to coordinate the air and fuel flows. A delay strategy and a simple compensation of fuel supply dynamics allow to obtain good results on engine bench. Uncoupling the acceleration pedal and the throttle command is a promising way to improve engine efficiency and reduce exhaust emission during transient phases. (author) 59 refs.

Towards Efficient Spectral Converters through Materials Design for Luminescent Solar Devices.

Science.gov (United States)

McKenna, Barry; Evans, Rachel C

2017-07-01

Single-junction photovoltaic devices exhibit a bottleneck in their efficiency due to incomplete or inefficient harvesting of photons in the low- or high-energy regions of the solar spectrum. Spectral converters can be used to convert solar photons into energies that are more effectively captured by the photovoltaic device through a photoluminescence process. Here, recent advances in the fields of luminescent solar concentration, luminescent downshifting, and upconversion are discussed. The focus is specifically on the role that materials science has to play in overcoming barriers in the optical performance in all spectral converters and on their successful integration with both established (e.g., c-Si, GaAs) and emerging (perovskite, organic, dye-sensitized) cell types. Current challenges and emerging research directions, which need to be addressed for the development of next-generation luminescent solar devices, are also discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Incentives to improve energy efficiency in EU Grids

Energy Technology Data Exchange (ETDEWEB)

Papaefthymiou, G.; Beestermoeller, C.; Gardiner, A.

2013-04-15

The Energy Efficiency Directive (2012/27/EU) includes provisions related to network tariffs and regulation. It is timely therefore to revisit the potential options for energy efficiency in grids, the treatment of energy efficiency in network tariffs and alternative policies for improving energy efficiency. This project builds on work done previously for the European Copper Institute in this area. In this paper, we concentrate on energy efficiency in electricity network design and operation. Other articles in the Directive relate to the role of the network tariffs and regulations in enabling or incentivising the provision of energy efficiency to end users. In section 2, we describe technical efficiency measures to reduce losses (improve energy efficiency) in the grid. Section 3 reviews grid tariffs in three countries to identify whether they provide incentives or disincentives for energy efficiency in the grid. Section 4 discusses and evaluates alternative regulations for energy efficiency in grids. Section 5 concludes and discusses the main components of the optimal policy framework.

Color-stable and efficient tandem white organic light-emitting devices using a LiF n-doping layer and a MoO{sub x} p-doping layer as charge generating unit

Energy Technology Data Exchange (ETDEWEB)

Chen, Yu; Wu, Qingyang; Zhang, Zhensong; Yue, Shouzhen; Guo, Runda; Wang, Peng; Wu, Mingzhu; Gou, Changhua; Zhao, Yi, E-mail: yizhao@jlu.edu.cn; Liu, Shiyong

2013-10-31

We have demonstrated color-stable and efficient tandem organic light-emitting devices (OLEDs) using 4,7-diphenyl-1,10-phenanthroline (Bphen):LiF/4,4′,4″-tris(N-3-methylphenyl-N-phenyl-amino)triphenylamine (m-MTDATA):molybdenum oxide (MoO{sub x}) as charge generating unit (CGU), which has the advantages of air stability and ease of fabrication; the working mechanism of Bphen:LiF/m-MTDATA:MoO{sub x} is also discussed through analysis of the electrical and spectral emission properties of tandem devices with different CGUs. The performance of tandem white OLED, comprising blue and yellow phosphorescent EL units, can be improved by optimizing the thickness of Bphen:LiF layer. The device comprised of 30 nm Bphen:LiF layer has a maximum current efficiency of 38.7 cd/A and it can still maintain 24.6 cd/A at the luminance of 10,370 cd/m{sup 2}. Moreover, the Commission Internationale de L'Eclairage (CIE) coordinates of the device are rather stable and the variation is only (± 0.003, ± 0.007) over a wide range of luminance (100–13,000 cd/m{sup 2}). - Highlights: • LiF n-doping layer and MoO{sub x} p-doping layer were used as charge generating units. • The device performance was improved by optimizing the thickness of n-doping layer. • High luminance and efficiency were both achieved at a very low current density. • The device showed rather stable spectra over a wide range of luminance.

Wild Band Edges: The Role of Bandgap Grading and Band-Edge Fluctuations in High-Efficiency Chalcogenide Devices: Preprint

Energy Technology Data Exchange (ETDEWEB)

Repins, Ingrid; Mansfield, Lorelle; Kanevce, Ana; Jensen, Soren A.; Kuciauskas, Darius; Glynn, Stephen; Barnes, Teresa; Metzger, Wyatt; Burst, James; Jiang, Chun-Sheng; Dippo, Patricia; Harvey, Steve; Teeter, Glenn; Perkins, Craig; Egaas, Brian; Zakutayev, Andriy; Alsmeier, J.-H.; Lussky, T.; Korte, L.; Wilks, R. G.; Bar, M.; Yan, Y.; Lany, Stephan; Zawadzki, Pawel; Park, Ji-Sang; Wei, Suhuai

2016-06-16

Band-edge effects -- including grading, electrostatic fluctuations, bandgap fluctuations, and band tails -- affect chalcogenide device efficiency. These effects now require more careful consideration as efficiencies increase beyond 20%. Several aspects of the relationships between band-edge phenomena and device performance for NREL absorbers are examined. For Cu(In,Ga)Se2 devices, recent increases in diffusion length imply changes to optimum bandgap profile. The origin, impact, and modification of electrostatic and bandgap fluctuations are also discussed. The application of the same principles to devices based on CdTe, kesterites, and emerging absorbers (Cu2SnS3, CuSbS2), considering differences in materials properties and defect formation energies, is examined.

Pyridine Based Polymer Light-Emitting Devices

National Research Council Canada - National Science Library

Wang, Y

1997-01-01

...) as a hole transporting/electron blocking layer. This improves the device efficiency and brightness significantly due to the charge confinement and exciplex emission at the PVK/emitting polymer interface...

Thermal efficiency improvements - an imperative for nuclear generating stations

International Nuclear Information System (INIS)

Hassanien, S.; Rouse, S.

1997-01-01

A one and a half percent thermal performance improvement of Ontario Hydro's operating nuclear units (Bruce B, Pickering B, and Darlington) means almost 980 GWh are available to the transmission system (assuming an 80% capacity factor). This is equivalent to the energy consumption of 34,000 electrically-heated homes in Ontario, and worth more than $39 million in revenue to Ontario Hydro Nuclear Generation. Improving nuclear plant thermal efficiency improves profitability (more GWh per unit of fuel) and competitiveness (cost of unit energy), and reduces environmental impact (less spent fuel and nuclear waste). Thermal performance will naturally decrease due to the age of the units unless corrective action is taken. Most Ontario Hydro nuclear units are ten to twenty years old. Some common causes for loss of thermal efficiency are: fouling and tube plugging of steam generators, condensers, and heat exchangers; steam leaks in the condenser due to valve wear, steam trap and drain leaks; deposition, pitting, cracking, corrosion, etc., of turbine blades; inadequate feedwater metering resulting from corrosion and deposition. This paper stresses the importance of improving the nuclear units' thermal efficiency. Ontario Hydro Nuclear has demonstrated energy savings results are achievable and affordable. Between 1994 and 1996, Nuclear reduced its energy use and improved thermal efficiency by over 430,000 MWh. Efficiency improvement is not automatic - strategies are needed to be effective. This paper suggests practical strategies to systematically improve thermal efficiency. (author)

Three-Dimensional Hetero-Integration of Faceted GaN on Si Pillars for Efficient Light Energy Conversion Devices.

Science.gov (United States)

Kim, Dong Rip; Lee, Chi Hwan; Cho, In Sun; Jang, Hanmin; Jeon, Min Soo; Zheng, Xiaolin

2017-07-25

An important pathway for cost-effective light energy conversion devices, such as solar cells and light emitting diodes, is to integrate III-V (e.g., GaN) materials on Si substrates. Such integration first necessitates growth of high crystalline III-V materials on Si, which has been the focus of many studies. However, the integration also requires that the final III-V/Si structure has a high light energy conversion efficiency. To accomplish these twin goals, we use single-crystalline microsized Si pillars as a seed layer to first grow faceted Si structures, which are then used for the heteroepitaxial growth of faceted GaN films. These faceted GaN films on Si have high crystallinity, and their threading dislocation density is similar to that of GaN grown on sapphire. In addition, the final faceted GaN/Si structure has great light absorption and extraction characteristics, leading to improved performance for GaN-on-Si light energy conversion devices.

Thermoelectric materials and devices made therewith

International Nuclear Information System (INIS)

Moore, D.E.

1985-01-01

The disclosed invention includes improved devices and materials for thermoelectric conversion, particularly for operation at temperatures of 300 0 C. and below. Disordered p-type semiconductor elements incorporate compound adjuvants of silver and lead to achieve enhanced ''figure of merit'' values and corresponding increased efficiencies of thermoelectric conversion. Similar results are obtained with disordered n-type elements by employing lowered selenium contents, preferably in combination with cuprous bromide. Improved conversion devices include powder pressed elements from one or both of these materials

Efficient single light-emitting layer pure blue phosphorescent organic light-emitting devices with wide gap host and matched interlayer

Energy Technology Data Exchange (ETDEWEB)

Jiang, Yunlong; Zhou, Liang, E-mail: zhoul@ciac.ac.cn; Cui, Rongzhen; Li, Yanan; Zhao, Xuesen; Zhang, Hongjie, E-mail: hongjie@ciac.ac.cn

2015-12-15

In this work, we report the highly efficient pure blue electroluminescent (EL) device based on bis[(3,5-difluoro-4-cyanophenyl)pyridine]picolinate iridium(III) (FCNIrpic) doped 9-(4-tert-Butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi) film. The matched energy levels of FCNIrpic and CzSi are helpful in facilitating the trapping of carriers, while the high triplet energy of CzSi can well avoid the undesired reverse energy transfer. More importantly, the injection of holes was further accelerated by inserting 5 nm 4,4′,4″-Tri(9-carbazoyl)triphenylamine (TcTa) film between hole transport layer and lighting-emitting layer (EML) as interlayer. Consequently, EL performances were significantly enhanced attributed to wider recombination zone and better balance of holes and electrons. Interestingly, single-EML device displayed higher performances than those of double-EMLs device. Finally, pure blue EL device with the structure of ITO/MoO{sub 3} (3 nm)/TAPC (40 nm)/TcTa (5 nm)/FCNIrpic (20%): CzSi (30 nm)/TmPyPB (40 nm)/LiF (1 nm)/Al (100 nm) realized the maximum brightness, current efficiency, power efficiency and external quantum efficiency up to 12,505 cd/m{sup 2}, 36.20 cd/A, 28.42 lm/W and 16.9%, respectively. Even at the high brightness of 1000 cd/m{sup 2}, current efficiency and external quantum efficiency up to 17.40 cd/A and 8.1%, respectively, can be retained by the same device.

Low Impedance Voice Coils for Improved Loudspeaker Efficiency

DEFF Research Database (Denmark)

Iversen, Niels Elkjær; Knott, Arnold; Andersen, Michael A. E.

2015-01-01

In modern audio systems utilizing switch-mode amplifiers the total efficiency is dominated by the rather poor efficiency of the loudspeaker. For decades voice coils have been designed so that nominal resistances of 4 to 8 Ohms is obtained, despite modern audio amplifiers, using switch-mode techno...... responses are estimated. For this woofer it is shown that the sensitivity can be improved approximately 1 dB, corresponding to a 30% efficiency improvement, just by increasing the fill factor using a low impedance voice coil with rectangular wire....

Thermoelectric generator performance analysis: Influence of pin tapering on the first and second law efficiencies

International Nuclear Information System (INIS)

Yilbas, B.S.; Ali, H.

2015-01-01

Highlights: • Double tapering of thermoelectric elements improves first and second law efficiency. • Pin geometric feature maximizing device output work does not maximize thermal efficiency. • Pin geometric feature maximizing first law efficiency slight alters for maximum second law efficiency. • External resistance and operating temperature ratios influence design configuration of thermoelectric generator. - Abstract: Thermoelectric generators are the important candidates for clean energy conversion from the waste heat; however, their low efficiency limits the practical applications of the devices. Tailoring the geometric configuration of the device in line with the operating conditions can improve the device performance. Consequently; in the present study, the influence of the pin geometric configuration on the thermoelectric generator performance is investigated. The dimensionless tapering parameter is introduced and its effect on the first and second law efficiencies is examined for various operating conditions including the external load resistance and the temperature ratio. It is found that the first and second law efficiencies are significantly influenced by the pin geometry. The dimensionless tapering parameter (a), increasing tapering of the thermoelectric pins, within the range of 2 ⩽ a ⩽ 4 results in improved first and second law efficiencies. However, the dimensionless tapering parameter maximizing the first and second law efficiencies does not maximize the device output power. This behavior is associated with the external load resistance which has a considerable influence on the device output power such that increasing external load resistance lowers the device output power

Wastewater treatment facilities: Energy efficient improvements and cogeneration

International Nuclear Information System (INIS)

Kunkle, R.; Gray, R.; Delzel, D.

1992-10-01

The Washington State Energy Office (WSEO) has worked with both the Bonneville Power Administration (BPA) and the US Department of Energy to provide technical and financial assistance to local governments. Based on a recent study conducted by Ecotope for WSEO, local governments spend an estimated $45 million on utility bills statewide. Water and wastewater facilities account for almost a third of this cost. As a result, WSEO decided to focus its efforts on the energy intensive water and wastewater sector. The ultimate goal of this project was to develop mechanisms to incorporate energy efficiency improvements into wastewater treatment facilities in retrofits and during upgrades, remodels, and new construction. Project activities included the following: The review of the existing regulatory environment for treatment system construction, A summary of financing options for efficiency improvements in treatment facilities, A literature review of energy efficiency opportunities in treatment plants, Survey and site visits to characterize existing facilities in Washington State, Estimates of the energy efficiency and cogeneration potential in the sector, and A case study to illustrate the implementation of an efficiency improvement in a treatment facility

Improved Efficient Routing Strategy on Scale-Free Networks

Science.gov (United States)

Jiang, Zhong-Yuan; Liang, Man-Gui

Since the betweenness of nodes in complex networks can theoretically represent the traffic load of nodes under the currently used routing strategy, we propose an improved efficient (IE) routing strategy to enhance to the network traffic capacity based on the betweenness centrality. Any node with the highest betweenness is susceptible to traffic congestion. An efficient way to improve the network traffic capacity is to redistribute the heavy traffic load from these central nodes to non-central nodes, so in this paper, we firstly give a path cost function by considering the sum of node betweenness with a tunable parameter β along the actual path. Then, by minimizing the path cost, our IE routing strategy achieved obvious improvement on the network transport efficiency. Simulations on scale-free Barabási-Albert (BA) networks confirmed the effectiveness of our strategy, when compared with the efficient routing (ER) and the shortest path (SP) routing.

Power Factor Improvement Using Automatic Power Factor Compensation (APFC Device for Medical Industries in Malaysia

Directory of Open Access Journals (Sweden)

Zaidi Maryam Nabihah

2018-01-01

Full Text Available This paper present the project designed to correcting power factor for medical industries in Malaysia automatically. Which with hope to make the cost and energy usage efficient, because the energy source are depleting due to increase in population. Power factor is the ratio of real power and apparent power. This definition is mathematically represented as kW/kVA where kW is active power and kVA is apparent power (active + reactive. Reactive power is the non-working power generated by the magnetic and inductive load to generate magnetic flux. The increase in reactive power increase the apparent power so the power factor will decrease. Low pF will cause the industry to meet high demand thus making it less efficient. The main aim of this project is to increasing the current power factor of medical industries from 0.85 to 0.90. Power factor compensation contribute to reduction in current-dependent losses and increase energy efficiency while expanding the reliability of planning for future energy network. As technology develops, the gradual cost and efficiency penalty should reduce. Therefore, automatic power factor compensation device should become cost-effective and smaller device over time. That is the reason this project is using programmable device as it is a miniature architecture device.

The gain from improved market efficiency

DEFF Research Database (Denmark)

Ejrnæs, Mette; Persson, Karl Gunnar

2010-01-01

demand as well as excess supply, which triggered off the tâtonnement process. Over time, adjustments to equilibrium, as measured by the half-life of a shock, became faster and violations of the law of one price become smaller. There were significant gains from improved market efficiency, which took place......This article looks at the gains from improved market efficiency in long-distance grain trade in the second half of the nineteenth century, when violations of the law of one price were reduced due to improved information transmission. Two markets, a major export centre, Chicago, and a major importer......, Liverpool, are analysed. We show that the law of one price equilibrium was an ‘attractor equilibrium'. The implication is that prices converged to that equilibrium in a tâtonnement process. Because of asymmetrically timed information between markets separated by long distances there were periods of excess...

Maximum Efficiency of Thermoelectric Heat Conversion in High-Temperature Power Devices

Directory of Open Access Journals (Sweden)

V. I. Khvesyuk

2016-01-01

Full Text Available Modern trends in development of aircraft engineering go with development of vehicles of the fifth generation. The features of aircrafts of the fifth generation are motivation to use new high-performance systems of onboard power supply. The operating temperature of the outer walls of engines is of 800–1000 K. This corresponds to radiation heat flux of 10 kW/m2 . The thermal energy including radiation of the engine wall may potentially be converted into electricity. The main objective of this paper is to analyze if it is possible to use a high efficiency thermoelectric conversion of heat into electricity. The paper considers issues such as working processes, choice of materials, and optimization of thermoelectric conversion. It presents the analysis results of operating conditions of thermoelectric generator (TEG used in advanced hightemperature power devices. A high-temperature heat source is a favorable factor for the thermoelectric conversion of heat. It is shown that for existing thermoelectric materials a theoretical conversion efficiency can reach the level of 15–20% at temperatures up to 1500 K and available values of Ioffe parameter being ZT = 2–3 (Z is figure of merit, T is temperature. To ensure temperature regime and high efficiency thermoelectric conversion simultaneously it is necessary to have a certain match between TEG power, temperature of hot and cold surfaces, and heat transfer coefficient of the cooling system. The paper discusses a concept of radiation absorber on the TEG hot surface. The analysis has demonstrated a number of potentialities for highly efficient conversion through using the TEG in high-temperature power devices. This work has been implemented under support of the Ministry of Education and Science of the Russian Federation; project No. 1145 (the programme “Organization of Research Engineering Activities”.

Discontinuous interleaving of parallel inverters for efficiency improvement

DEFF Research Database (Denmark)

Rannestad, Bjørn; Munk-Nielsen, Stig; Gadgaard, Kristian

2017-01-01

Interleaved switching of parallel inverters has previously been proposed for efficiency/size improvements of grid connected three-phase inverters. This paper proposes a novel interleaving method which practically eliminates insulated gate bipolar transistor (IGBT) turn-on losses and drastically...... overall power module losses are reduced. The modulation strategy is suited for converters with doubly fed induction generators (DFIG) for wind turbines, but are not limited hereto. Improvement of switching performance are measured and operational efficiency improvements are calculated and verified...

Light-induced lattice expansion leads to high-efficiency perovskite solar cells

Energy Technology Data Exchange (ETDEWEB)

Tsai, Hsinhan; Asadpour, Reza; Blancon, Jean-Christophe; Stoumpos, Constantinos C.; Durand, Olivier; Strzalka, Joseph W.; Chen, Bo; Verduzco, Rafael; Ajayan, Pulickel M.; Tretiak, Sergei; Even, Jacky; Alam, Muhammad Ashraf; Kanatzidis, Mercouri G.; Nie, Wanyi; Mohite, Aditya D.

2018-04-05

Hybrid-perovskite based high-performance optoelectronic devices and clues from their operation has led to the realization that light-induced structural dynamics play a vital role on their physical properties, device performance and stability. Here, we report that continuous light illumination leads to a uniform lattice expansion in hybrid perovskite thin-films, which is critical for obtaining high-efficiency photovoltaic devices. Correlated, in-situ structural and device characterizations reveal that light-induced lattice expansion significantly benefits the performances of a mixed-cation pure-halide planar device, boosting the power conversion efficiency from 18.5% to 20.5%. This is a direct consequence of the relaxation of local lattice strains during lattice expansion, which results in the reduction of the energetic barriers at the perovskite/contact interfaces in devices, thus improving the open circuit voltage and fill factor. The light-induced lattice expansion stabilizes these high-efficiency photovoltaic devices under continuous operation of full-spectrum 1-Sun illumination for over 1500 hours. One Sentence Summary: Light-induced lattice expansion improves crystallinity, relaxes lattice strain, which enhances photovoltaic performance in hybrid perovskite device.

Monolayer-Mediated Growth of Organic Semiconductor Films with Improved Device Performance.

Science.gov (United States)

Huang, Lizhen; Hu, Xiaorong; Chi, Lifeng

2015-09-15

Increased interest in wearable and smart electronics is driving numerous research works on organic electronics. The control of film growth and patterning is of great importance when targeting high-performance organic semiconductor devices. In this Feature Article, we summarize our recent work focusing on the growth, crystallization, and device operation of organic semiconductors intermediated by ultrathin organic films (in most cases, only a monolayer). The site-selective growth, modified crystallization and morphology, and improved device performance of organic semiconductor films are demonstrated with the help of the inducing layers, including patterned and uniform Langmuir-Blodgett monolayers, crystalline ultrathin organic films, and self-assembled polymer brush films. The introduction of the inducing layers could dramatically change the diffusion of the organic semiconductors on the surface and the interactions between the active layer with the inducing layer, leading to improved aggregation/crystallization behavior and device performance.

Microfabricated fuel heating value monitoring device

Science.gov (United States)

Robinson, Alex L [Albuquerque, NM; Manginell, Ronald P [Albuquerque, NM; Moorman, Matthew W [Albuquerque, NM

2010-05-04

A microfabricated fuel heating value monitoring device comprises a microfabricated gas chromatography column in combination with a catalytic microcalorimeter. The microcalorimeter can comprise a reference thermal conductivity sensor to provide diagnostics and surety. Using microfabrication techniques, the device can be manufactured in production quantities at a low per-unit cost. The microfabricated fuel heating value monitoring device enables continuous calorimetric determination of the heating value of natural gas with a 1 minute analysis time and 1.5 minute cycle time using air as a carrier gas. This device has applications in remote natural gas mining stations, pipeline switching and metering stations, turbine generators, and other industrial user sites. For gas pipelines, the device can improve gas quality during transfer and blending, and provide accurate financial accounting. For industrial end users, the device can provide continuous feedback of physical gas properties to improve combustion efficiency during use.

Recovery Act--Class 8 Truck Freight Efficiency Improvement Project

Energy Technology Data Exchange (ETDEWEB)

Trucks, Daimler [Daimler Trucks North America Llc, Portland, OR (United States)

2015-07-26

Daimler Trucks North America completed a five year, $79.6M project to develop and demonstrate a concept vehicle with at least 50% freight efficiency improvement over a weighted average of several drive cycles relative to a 2009 best-in-class baseline vehicle. DTNA chose a very fuel efficient baseline vehicle, the 2009 Freightliner Cascadia with a DD15 engine, yet successfully demonstrated a 115% freight efficiency improvement. DTNA learned a great deal about the various technologies that were incorporated into Super Truck and those that, through down-selection, were discarded. Some of the technologies competed with each other for efficiency, and notably some of the technologies complemented each other. For example, we found that Super Truck’s improved aerodynamic drag resulted in improved fuel savings from eCoast, relative to a similar vehicle with worse aerodynamic drag. However, some technologies were in direct competition with each other, namely the predictive technologies which use GPS and 3D digital maps to efficiently manage the vehicles kinetic energy through controls and software, versus hybrid which is a much costlier technology that essentially targets the same inefficiency. Furthermore, the benefits of a comprehensive, integrated powertrain/vehicle approach was proven, in which vast improvements in vehicle efficiency (e.g. lower aero drag and driveline losses) enabled engine strategies such as downrating and downspeeding. The joint engine and vehicle developments proved to be a multiplier-effect which resulted in large freight efficiency improvements. Although a large number of technologies made the selection process and were used on the Super Truck demonstrator vehicle, some of the technologies proved not feasible for series production.

Recombination region improvement for reduced efficiency roll-off in phosphorescent OLEDs with dual emissive layers

Energy Technology Data Exchange (ETDEWEB)

Ma, Zhu; Zhou, Shunliang [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Hu, Song [Chengdu Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

2014-10-15

High-performance phosphorescent organic light-emitting diodes (PhOLEDs) by using dual-emissive-layer (DEL) structure to reduce efficiency roll-off were fabricated. The DEL was comprised of a hole-transport-type host of N, N′-bis(naphthalen-1-yl)-N, N′-bis(phenyl)-benzidine (NPB) and a bipolar host of 4,4′-bis(carbazol-9-yl)biphenyl (CBP), which were both doped with an orange phosphorescent dopant of bis[2-(4-tert-butylphenyl)-benzothiazolato-N,C2′]iridium (acetylacetonate) [(t-bt){sub 2}Ir(acac)]. After the optimization of doping concentration of the first emissive layer (FEL), the device with DEL exhibited 11% lower roll-off power efficiency than single emissive layer devices (SED) when the luminance increased from 1000 cd/m{sup 2} to 10,000 cd/m{sup 2}. The hole–electron recombination zone in DEL was illuminated by inserting an ultrathin fluorescent probe of 4-(dicyanomethylene)-2-tert-butyl-6 (1,1,7,7-tetramethyljulolidin-4-yl-vinyl)-4H-pyran (DCJTB) in different emissive regions. The performance improvement was attributed to the optimization of energy barrier and the expansion of exciton formation zone within the DEL. - Highlights: • PhOLEDs by using a dual-emissive-layer structure to reduce efficiency roll-off were fabricated. • The DED exhibited 11% lower efficiency roll-off, 57% lower turn-on voltage, and 174% higher brightness than SED. • A DCJTB fluorescent probe was inserted at different positions of DED to investigate the expansion of exciton formation zone.

Improved Morphology and Efficiency of n-i-p Planar Perovskite Solar Cells by Processing with Glycol Ether Additives

KAUST Repository

Ugur, Esma

2017-07-31

Planar perovskite solar cells can be prepared without high temperature processing steps typically associated with mesoporous device architectures; however, their efficiency has been lower and producing high quality perovskite films in planar devices has been challenging. Here, we report a modified two-step interdiffusion protocol suitable to prepare pin-hole free perovskite films with greatly improved morphology. This is achieved by simple addition of small amounts of glycol ethers to the preparation protocol. We unravel the impact the glycol ethers have on the perovskite film formation using in-situ UV-Vis absorbance and GIWAXS experiments. From these experiments we conclude: addition of glycol ethers changes the lead iodide to perovskite conversion dynamics and enhances the conversion efficiency, resulting in more compact polycrystalline films, and it creates micrometer-sized perovskite crystals vertically-aligned across the photoactive layer. Consequently, the average photovoltaic performance increases from 13.5% to 15.9% and reproduciability is enhanced, specifically when 2-methoxyethanol is used as additive.

Improved Morphology and Efficiency of n-i-p Planar Perovskite Solar Cells by Processing with Glycol Ether Additives

KAUST Repository

Ugur, Esma; Sheikh, Arif D.; Munir, Rahim; Khan, Jafar Iqbal; Barrit, Dounya; Amassian, Aram; Laquai, Fré dé ric

2017-01-01

Planar perovskite solar cells can be prepared without high temperature processing steps typically associated with mesoporous device architectures; however, their efficiency has been lower and producing high quality perovskite films in planar devices has been challenging. Here, we report a modified two-step interdiffusion protocol suitable to prepare pin-hole free perovskite films with greatly improved morphology. This is achieved by simple addition of small amounts of glycol ethers to the preparation protocol. We unravel the impact the glycol ethers have on the perovskite film formation using in-situ UV-Vis absorbance and GIWAXS experiments. From these experiments we conclude: addition of glycol ethers changes the lead iodide to perovskite conversion dynamics and enhances the conversion efficiency, resulting in more compact polycrystalline films, and it creates micrometer-sized perovskite crystals vertically-aligned across the photoactive layer. Consequently, the average photovoltaic performance increases from 13.5% to 15.9% and reproduciability is enhanced, specifically when 2-methoxyethanol is used as additive.

Measure of the volumetric efficiency and evaporator device performance for a liquefied petroleum gas spark ignition engine

International Nuclear Information System (INIS)

Masi, Massimo; Gobbato, Paolo

2012-01-01

Highlights: ► Measure of the effect of LPG fuel on volumetric efficiency of a SI petrol ICE. ► Steady-state and transient performance of a LPG evaporator device on a SI ICE. ► Volume displaced by LPG causes slight performance loss in SI petrol engines. ► LPG reveals peak efficiency and high-efficiency range wider than petrol in SI ICE’s. ► One-stage pressure reducer for LPG performs satisfactorily during SI ICE transients. - Abstract: The use of Liquefied Petroleum Gas (LPG) as fuel for spark ignition engines originally designed to be gasoline fuelled is common practice in many countries. Despite this, some questions remain still open. The present paper deals with the two main problems related to LPG port-fuel SI engines: the volumetric efficiency drop and the LPG evaporator device performance. A passengers car SI engine equipped with a “third generation” kit for the dual-fuel operation was tested using a dynamometer test rig. A single-stage pressure reducer was selected as LPG evaporator, to take advantage of an additional pre-heating of the liquid LPG that allows higher power output than a two-stage device of the same size. Engine performance, volumetric efficiency and change of LPG thermodynamic states in the evaporator were measured both in steady-state and transient operation of the engine. Steady-state measurements show the advantage of LPG in terms of engine efficiency, and quantify the drop in steady-state brake torque due to the volume swept by gaseous fuel in the fresh charge admission process. On the other hand, transient measurements show that a single-stage evaporator device is capable to match overall simplicity and satisfactory performance during strong changes in engine load.

A treatment of thermal efficiency improvement in the Brayton cycle

International Nuclear Information System (INIS)

Fujii, Terushige; Akagawa, Koji; Nakanishi, Shigeyasu; Inoue, Kiyoshi; Ishigai, Seikan.

1982-01-01

So far, as the working fluid for power-generating plants, mainly water and air (combustion gas) have been used. In this study, in regeneration and isothermal compression processes being considered as the means for the efficiency improvement in Brayton cycle, the investigation of equivalent graphical presentation method with T-S diagrams, the introduction of the new characteristic number expressing the possibility of thermal efficiency improvement by regeneration, and the investigation of the effect of the difference of working fluid on thermal efficiency were carried out. Next, as the cycle approximately realizing isothermal compression process with condensation process, the super-critical pressure cycle with liquid phase compression was rated, and four working fluids, NH 3 , SO 2 , CO 2 and H 2 O were examined as perfect gas and real gas. The advantage of CO 2 regeneration for the thermal efficiency improvement was clarified by using the dimensionless characteristic number. The graphical presentation of effective work, the thermal efficiency improvement by regeneration, the thermal efficiency improvement by making compression process isothermal, the effect on thermal efficiency due to various factors and working fluids, the characteristic number by regeneration, and the application to real working fluids are reported. (Kako, I.)

Organic Optoelectronic Devices Employing Small Molecules

Science.gov (United States)

Fleetham, Tyler Blain

Organic optoelectronic devices have remained a research topic of great interest over the past two decades, particularly in the development of efficient organic photovoltaics (OPV) and organic light emitting diodes (OLED). In order to improve the efficiency, stability, and materials variety for organic optoelectronic devices a number of emitting materials, absorbing materials, and charge transport materials were developed and employed in a device setting. Optical, electrical, and photophysical studies of the organic materials and their corresponding devices were thoroughly carried out. Two major approaches were taken to enhance the efficiency of small molecule based OPVs: developing material with higher open circuit voltages or improved device structures which increased short circuit current. To explore the factors affecting the open circuit voltage (VOC) in OPVs, molecular structures were modified to bring VOC closer to the effective bandgap, DeltaE DA, which allowed the achievement of 1V VOC for a heterojunction of a select Ir complex with estimated exciton energy of only 1.55eV. Furthermore, the development of anode interfacial layer for exciton blocking and molecular templating provide a general approach for enhancing the short circuit current. Ultimately, a 5.8% PCE was achieved in a single heterojunction of C60 and a ZnPc material prepared in a simple, one step, solvent free, synthesis. OLEDs employing newly developed deep blue emitters based on cyclometalated complexes were demonstrated. Ultimately, a peak EQE of 24.8% and nearly perfect blue emission of (0.148,0.079) was achieved from PtON7dtb, which approaches the maximum attainable performance from a blue OLED. Furthermore, utilizing the excimer formation properties of square-planar Pt complexes, highly efficient and stable white devices employing a single emissive material were demonstrated. A peak EQE of over 20% for pure white color (0.33,0.33) and 80 CRI was achieved with the tridentate Pt complex, Pt

Flaw detection device for plasma facing wall in thermonuclear device

International Nuclear Information System (INIS)

Doi, Akira.

1996-01-01

The present invention concerns plasma facing walls of a thermonuclear device and provides a device for detecting a thickness of amour tiles accurately and efficiently with no manual operation. Namely, the position of the plasma facing surface of the amour tile is measured using a structure to which the amour tiles are to be disposed as a reference. Also in a case of disposing new armor tiles, the position of the plasma facing surface of the armor tiles is measured to thereby measure the wearing amount of the amour tiles based on the difference between the reference and the measured value. If a measuring means capable of measuring a plurality of amour tiles at once is used efficiency of the measurement and the detection can be enhanced. Several ten thousands of amour tiles are disposed to the plasma facing wall in a large scaled thermonuclear device, and a plenty of time was required for the detection. However, the present invention can improve the accuracy for the measurement and detection and provide time and labors-saving. (I.S.)

SAGD CO2 mitigation through energy efficiency improvements

International Nuclear Information System (INIS)

Plessis du, D.

2010-01-01

An evaluation of the carbon dioxide (CO 2 ) emissions reductions achieved using energy efficiency measures in steam assisted gravity drainage (SAGD) operations was presented. The efficiency of a typical SAGD operation was analyzed using an indexing tool based on the Carnot cycle efficiency to develop an ideal SAGD heat cycle. The benefits of using an organic Rankine cycle (ORC) technology to convert waste heat to electrical power were also investigated. A CO 2 abatement curve was used to identify the economic benefits and costs of various greenhouse gas (GHG) reductions. The level of recovered energy was determined in relation to energy prices, capital costs, and carbon penalties in order to determine the most efficient means of decreasing energy usage. The study demonstrated that energy efficiency can be improved by up to 20 percent, and water loss reductions of up to 50 percent can be achieved using cost-effective energy efficiency measures. Results of the study can be used to guide government policy and provide industry with practical tools to benchmark performance and improve efficiencies. 4 refs., 1 tab., 10 figs.

Availability and improvement of a vacuum-type immobilization device in pediatric CT

International Nuclear Information System (INIS)

Tani, Shoji; Mizuno, Naoto; Abe, Syuji

2002-01-01

The essential factors for an immobilization device in pediatric CT are absence of artifacts, safety, no disturbance of the patient's sedation, and ease of handling. We evaluated the suitability of a commercially available vacuum-type immobilization device designed for radiation therapy (Vac-Lok) that meets these requisites. There were no artifacts in scans of the water phantom. The device easily immobilized the patient, was quick to release, and was superior to previous immobilization systems, according to replies to a questionnaire administered to physicians, technologists, and nurses. Schedule delays were reduced by using this device to examine sedated patients (up to 1 year of age). Despite these advantages, the device was too small to immobilize both extremities together when examining older patients. In order to overcome this problem, we invented a special immobilization device for pediatric CT. The new device could be applied to taller patients, up to 85 cm in height (the average height of 2-year-old infants), and was able to contribute to efficient utilization of the examination room. (author)

EFFICIENT USE OF BIOMASS IN IMPROVED COOKSTOVES

Directory of Open Access Journals (Sweden)

R. K. PAL

2016-12-01

Full Text Available Traditional biomass cookstoves have very low efficiency. The improved cookstoves have very high efficiency. These improved cookstoves with high efficiency saves biomass fuels. Biomass can be saved in case of rocket elbow cookstoves. The amount of biomass which can be saved in case of rocket elbow cookstoves is 65.88 MT. More biomass can be saved in case of gasifier fan cookstoves. The amount of biomass which can be saved is 155.71 MT. The pollutants like particulate matter, black carbon, carbon mono-oxide and carbon dioxide emission is lesser in case of rocket elbow cookstoves. The pollutants are least in case of gasifier fan cookstoves. The reduction in particulate matter, black carbon, carbon mono-oxide and carbon dioxide emission in gasifier fan cookstoves is 1.77 MT, 0.24 MT, 0.71 MT & 151.64 MT respectively in comparison to traditional cookstoves. Therefore indoor air pollution is greatly reduced in case of improved cookstoves especially in case of gasifier fan cookstoves as compared to traditional cookstoves.

Barriers to improvements in energy efficiency

Energy Technology Data Exchange (ETDEWEB)

Reddy, A.K.N.

1991-10-01

To promote energy-efficiency improvements, actions may be required at one or more levels -- from the lowest level of the consumer (residential, commercial, industrial, etc.) through the highest level of the global agencies. But barriers to the implementation of energy-efficiency improvements exist or can arise at all these levels. Taking up each one of these barriers in turn, the paper discusses specific measures that can contribute to overcoming the barriers. However, a one-barrier-one-measure approach must be avoided. Single barriers may in fact involve several sub-barriers. Also, combinations of measures are much more effective in overcoming barriers. In particular, combinations of measures that simultaneously overcome several barriers are most successful. The paper discusses the typology of barriers, explores their origin and suggests measures that by themselves or in combination with other measures, will overcome these barriers. Since most of the barriers dealt with can be found in the barriers'' literature, any originality in the paper lies in its systematic organization, synoptic view and holistic treatment of this issue. This paper is intended to initiate a comprehensive treatment of barriers, their origins and the measures that contribute to overcoming them. Hopefully, such a treatment will facilitate the implementation of energy-efficiency improvements involving a wide diversity of ever-changing energy end uses and consumer preferences.

Barriers to improvements in energy efficiency

Energy Technology Data Exchange (ETDEWEB)

Reddy, A.K.N.

1991-10-01

To promote energy-efficiency improvements, actions may be required at one or more levels -- from the lowest level of the consumer (residential, commercial, industrial, etc.) through the highest level of the global agencies. But barriers to the implementation of energy-efficiency improvements exist or can arise at all these levels. Taking up each one of these barriers in turn, the paper discusses specific measures that can contribute to overcoming the barriers. However, a one-barrier-one-measure approach must be avoided. Single barriers may in fact involve several sub-barriers. Also, combinations of measures are much more effective in overcoming barriers. In particular, combinations of measures that simultaneously overcome several barriers are most successful. The paper discusses the typology of barriers, explores their origin and suggests measures that by themselves or in combination with other measures, will overcome these barriers. Since most of the barriers dealt with can be found in the ``barriers`` literature, any originality in the paper lies in its systematic organization, synoptic view and holistic treatment of this issue. This paper is intended to initiate a comprehensive treatment of barriers, their origins and the measures that contribute to overcoming them. Hopefully, such a treatment will facilitate the implementation of energy-efficiency improvements involving a wide diversity of ever-changing energy end uses and consumer preferences.

Improved quantum efficiency models of CZTSe: GE nanolayer solar cells with a linear electric field.

Science.gov (United States)

Lee, Sanghyun; Price, Kent J; Saucedo, Edgardo; Giraldo, Sergio

2018-02-08

We fabricated and characterized CZTSe:Ge nanolayer (quantum efficiency for Ge doped CZTSe devices. The linear electric field model is developed with the incomplete gamma function of the quantum efficiency as compared to the empirical data at forward bias conditions. This model is characterized with a consistent set of parameters from a series of measurements and the literature. Using the analytical modelling method, the carrier collection profile in the absorber is calculated and closely fitted by the developed mathematical expressions to identify the carrier dynamics during the quantum efficiency measurement of the device. The analytical calculation is compared with the measured quantum efficiency data at various bias conditions.

Accuracy of an improved device for remote measuring of tree-trunk diameters

International Nuclear Information System (INIS)

Matsushita, T.; Kato, S.; Komiyama, A.

2000-01-01

For measuring the diameters of tree trunks from a distant position, a recent device using a laser beam was developed by Kantou. We improved this device to serve our own practical purposes. The improved device consists of a 1-m-long metal caliper and a small telescope sliding smoothly onto it. Using the cross hairs in the scope, one can measure both edges of an object on the caliper and calculate its length. The laser beam is used just for guiding the telescopic sights to the correct positions on the object. In this study, the accuracy of this new device was examined by measuring objects of differing lengths, the distance from the object, and the angle of elevation to the object. Since each result of the experiment predicted absolute errors of measurement of less than 3 mm, this new device will be suitable for the measurement of trunk diameters in the field

Mixing of phosphorescent and exciplex emission in efficient organic electroluminescent devices.

Science.gov (United States)

Cherpak, Vladyslav; Stakhira, Pavlo; Minaev, Boris; Baryshnikov, Gleb; Stromylo, Evgeniy; Helzhynskyy, Igor; Chapran, Marian; Volyniuk, Dmytro; Hotra, Zenon; Dabuliene, Asta; Tomkeviciene, Ausra; Voznyak, Lesya; Grazulevicius, Juozas Vidas

2015-01-21

We fabricated a yellow organic light-emitting diode (OLED) based on the star-shaped donor compound tri(9-hexylcarbazol-3-yl)amine, which provides formation of the interface exciplexes with the iridium(III) bis[4,6-difluorophenyl]-pyridinato-N,C2']picolinate (FIrpic). The exciplex emission is characterized by a broad band and provides a condition to realize the highly effective white OLED. It consists of a combination of the blue phosphorescent emission from the FIrpic complex and a broad efficient delayed fluorescence induced by thermal activation with additional direct phosphorescence from the triplet exciplex formed at the interface. The fabricated exciplex-type device exhibits a high brightness of 38 000 cd/m(2) and a high external quantum efficiency.

Measures for energy efficiency improvement of buildings

Directory of Open Access Journals (Sweden)

Vukadinović Ana V.

2015-01-01

Full Text Available The increase in energy consumption in buildings causes the need to propose energy efficiency improvement measures. Urban planning in accordance with micro location conditions can lead to energy consumption reduction in buildings through the passive solar design. While satisfying the thermal comfort to the user space purpose, energy efficiency can be achieved by optimizing the architectural and construction parameters such as shape of the building, envelope structure and the percentage of glazing. The improvement of the proposed measures, including the use of renewable energy sources, can meet requirements of Directive 2010/31 / EU of 'nearly zero energy buildings'.

Parking lot runoff quality and treatment efficiencies of a hydrodynamic-settling device in Madison, Wisconsin, 2005-6

Science.gov (United States)

Horwatich, Judy A.; Bannerman, Roger T.

2012-01-01

A hydrodynamic-settling device was installed in 2004 to treat stormwater runoff from a roof and parking lot located at the Water Utility Administration Building in Madison, Wis. The U.S. Geological Survey, in cooperation with the Wisconsin Department of Natural Resources, the City of Madison, cities in the Waukesha Permit Group, Hydro International, Earth Tech, Inc., National Sanitation Foundation International, and the U.S. Environmental Protection Agency, monitored the device from November 2005 through September 2006 to evaluate it as part of the U.S. Environmental Protection Agency's Environmental Technology Verification Program. Twenty-three runoff events monitored for flow volume and water quality at the device's inlet and outlet were used to calculate the percentage of pollutant reduction for the device. The geometric mean concentrations of suspended sediment (SS), "adjusted" total suspended solids (TSS), total phosphorus (TP), dissolved phosphorus (DP), total recoverable zinc (TZn), and total recoverable copper (TCu) measured at the inlet were 107 mg/L (milligrams per liter), 92 mg/L, 0.17 mg/L, 0.05 mg/L, 38 μg/L (micrograms per liter), and 12 μg/L, respectively, and these concentrations are in the range of values observed in stormwater runoff from other parking lots in Wisconsin and Michigan. Efficiency of the settling device was calculated using the efficiency ratio and summation of loads (SOL) methods. Using the efficiency ratio method, the device reduced concentrations of SS, and DP, by 19, and 15, percent, respectively. Using the efficiency ratio method, the device increased "adjusted" TSS and TZn concentrations by 5 and 19, respectively. Bypass occurred for 3 of the 23 runoff events used in this assessment, and the bypass flow and water-quality concentrations were used to determine the efficiency of the bypass system. Concentrations of SS, "adjusted" TSS, and DP were reduced for the system by 18, 5, and 18, respectively; however, TZn increased by 5

Device Engineering Towards Improved Tin Sulfide Solar Cell Performance and Performance Reproducibility

Energy Technology Data Exchange (ETDEWEB)

Steinmann, Vera; Chakraborty, Rupak; Rekemeyer, Paul; Siol, Sebastian; Martinot, Loic; Polizzotti, Alex; Yang, Chuanxi; Hartman, Katy; Gradecak, Silvija; Zakutayev, Andriy; Gordon, Roy G.; Buonassisi, Tonio

2016-11-21

As novel absorber materials are developed and screened for their photovoltaic (PV) properties, the challenge remains to rapidly test promising candidates in high-performing PV devices. There is a need to engineer new compatible device architectures, including the development of novel transparent conductive oxides and buffer layers. Here, we consider the two approaches of a substrate-style and a superstrate-style device architecture for novel thin-film solar cells. We use tin sulfide as a test absorber material. Upon device engineering, we demonstrate new approaches to improve device performance and performance reproducibility.

Potential Global Benefits of Improved Ceiling Fan Energy Efficiency

Energy Technology Data Exchange (ETDEWEB)

Sathaye, Nakul [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Phadke, Amol [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shah, Nihar [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Letschert, Virginie [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2012-10-31

Ceiling fans contribute significantly to residential electricity consumption, both in an absolute sense and as a proportion of household consumption in many locations, especially in developing countries in warm climates. However, there has been little detailed assessment of the costs and benefits of efficiency improvement options for ceiling fans and the potential resulting electricity consumption and greenhouse gas (GHG) emissions reductions. We analyze the costs and benefits of several options to improve the efficiency of ceiling fans and assess the global potential for electricity savings and GHG emission reductions with more detailed assessments for India, China, and the U.S. We find that ceiling fan efficiency can be cost-effectively improved by at least 50% using commercially available technology. If these efficiency improvements are implemented in all ceiling fans sold by 2020, 70 terrawatt hours per year (TWh/year) could be saved and 25 million metric tons of carbon dioxide (CO2) emissions per year could be avoided, globally. We assess how policies and programs such as standards, labels, and financial incentives can be used to accelerate the adoption of efficient ceiling fans in order to realize this savings potential.

The development of furrower model blade to paddlewheel aerator for improving aeration efficiency

Science.gov (United States)

Bahri, Samsul; Praeko Agus Setiawan, Radite; Hermawan, Wawan; Zairin Junior, Muhammad

2018-05-01

The successful of intensive aquaculture is strongly influenced by the ability of the farmers to overcome the deterioration of water quality. The problem is low dissolved oxygen through aeration process. The aerator device which widely used in pond farming is paddle wheel aerator because it is the best aerator in aeration mechanism and usable driven power. However, this aerator still has a low performance of aeration, so that the cost of aerator operational for aquaculture is still high. Up to now, the effort to improve the performance of aeration was made by two-dimensional blade design. Obviously, it does not provide the optimum result due to the power requirements for aeration is directly proportional to the increase of aeration rate. The aim of this research is to develop three-dimensional model furrowed blades. Design of Furrower model blades was 1.6 cm diameter hole, 45º of vertical angle blade position and 30º of the horizontal position. The optimum performance furrowed model blades operated on the submerged blade 9 cm with 567.54 Watt of electrical power consumption and 4.322 m3 of splash coverage volume. The standard efficiency aeration is 2.72 kg O2 kWh-1. The furrowed model blades can improve the aeration efficiency of paddlewheel aerator.

The effect of device-based cardiac contractility modulation therapy on myocardial efficiency and oxidative metabolism in patients with heart failure

International Nuclear Information System (INIS)

Goliasch, Georg; Khorsand, Aliasghar; Sochor, Heinz; Schmidinger, Herwig; Graf, Senta; Schuetz, Matthias; Karanikas, Georgios; Khazen, Cesar; Wolzt, Michael

2012-01-01

Cardiac contractility modulation (CCM) is a device-based therapy that involves delivery of nonexcitatory electrical signals resulting in improved ventricular function and a reversal of maladaptive cardiac fetal gene programmes. Our aim was to evaluate whether acute application of CCM leads to an increase in myocardial oxygen consumption (MVO 2 ) in patients with chronic heart failure using 11 C-acetate positron emission tomography (PET). We prospectively enrolled 21 patients with severe heart failure. 11 C-acetate PET was performed before and after activation of the CCM device. In 12 patients an additional stress study with dobutamine was performed. Under resting conditions, the values of myocardial blood flow (MBF), MVO 2 and work metabolic index (WMI, reflecting myocardial efficiency) with the CCM device activated did not differ significantly from the values with the device deactivated. MBF was 0.81 ± 0.18 ml min -1 g -1 with the device off and 0.80 ± 0.15 ml min -1 g -1 with the device on (p = 0.818), MVO 2 was 6.81 ± 1.69 ml/min/100 g with the device off and 7.15 ± 1.62 ml/min/100 g with the device on (p = 0.241) and WMI was 4.94 ± 1.14 mmHg ml/m 2 with the device off and 5.21 ± 1.36 mmHg ml/m 2 with the device on (p = 0.344). Under dobutamine stress, the values of MBF, MVO 2 and WMI with the CCM device activated did not differ from the values with the device deactivated, but were significantly increased compared with the values obtained under resting conditions. These results indicate that CCM does not induce increased MVO 2 , even under stress conditions. (orig.)

The effect of device-based cardiac contractility modulation therapy on myocardial efficiency and oxidative metabolism in patients with heart failure

Energy Technology Data Exchange (ETDEWEB)

Goliasch, Georg; Khorsand, Aliasghar; Sochor, Heinz; Schmidinger, Herwig; Graf, Senta [Vienna General Hospital/Medical University of Vienna, Department of Cardiology, Vienna (Austria); Schuetz, Matthias; Karanikas, Georgios [Vienna General Hospital/Medical University of Vienna, Department of Nuclear Medicine, Vienna (Austria); Khazen, Cesar [Vienna General Hospital/ Medical University of Vienna, Department of Cardiothoracic Surgery, Vienna (Austria); Wolzt, Michael [Vienna General Hospital/Medical University of Vienna, Department of Cardiology, Vienna (Austria); Vienna General Hospital/ Medical University of Vienna, Department of Clinical Pharmacology, Vienna (Austria)

2012-03-15

Cardiac contractility modulation (CCM) is a device-based therapy that involves delivery of nonexcitatory electrical signals resulting in improved ventricular function and a reversal of maladaptive cardiac fetal gene programmes. Our aim was to evaluate whether acute application of CCM leads to an increase in myocardial oxygen consumption (MVO{sub 2}) in patients with chronic heart failure using {sup 11}C-acetate positron emission tomography (PET). We prospectively enrolled 21 patients with severe heart failure. {sup 11}C-acetate PET was performed before and after activation of the CCM device. In 12 patients an additional stress study with dobutamine was performed. Under resting conditions, the values of myocardial blood flow (MBF), MVO{sub 2} and work metabolic index (WMI, reflecting myocardial efficiency) with the CCM device activated did not differ significantly from the values with the device deactivated. MBF was 0.81 {+-} 0.18 ml min{sup -1} g{sup -1} with the device off and 0.80 {+-} 0.15 ml min{sup -1} g{sup -1} with the device on (p = 0.818), MVO{sub 2} was 6.81 {+-} 1.69 ml/min/100 g with the device off and 7.15 {+-} 1.62 ml/min/100 g with the device on (p = 0.241) and WMI was 4.94 {+-} 1.14 mmHg ml/m{sup 2} with the device off and 5.21 {+-} 1.36 mmHg ml/m{sup 2} with the device on (p = 0.344). Under dobutamine stress, the values of MBF, MVO{sub 2} and WMI with the CCM device activated did not differ from the values with the device deactivated, but were significantly increased compared with the values obtained under resting conditions. These results indicate that CCM does not induce increased MVO{sub 2}, even under stress conditions. (orig.)

Quality and Efficiency Improvement Tools for Every Radiologist.

Science.gov (United States)

Kudla, Alexei U; Brook, Olga R

2018-03-20

In an era of value-based medicine, data-driven quality improvement is more important than ever to ensure safe and efficient imaging services. Familiarity with high-value tools enables all radiologists to successfully engage in quality and efficiency improvement. In this article, we review the model for improvement, strategies for measurement, and common practical tools with real-life examples that include Run chart, Control chart (Shewhart chart), Fishbone (Cause-and-Effect or Ishikawa) diagram, Pareto chart, 5 Whys, and Root Cause Analysis. Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Highly efficient and concentration-insensitive organic light-emitting devices based on self-quenching-resistant orange–red iridium complex

Energy Technology Data Exchange (ETDEWEB)

Qi, Yige; Wang, Xu [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Li, Ming [College of Chemistry, Sichuan University, Chengdu 610064 (China); Lu, Zhiyun, E-mail: luzhiyun@scu.edu.cn [College of Chemistry, Sichuan University, Chengdu 610064 (China); Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

2014-11-15

Orange–red phosphorescent organic light-emitting devices (PHOLEDs) with high efficiency and concentration insensitivity based on a novel iridium complex, bis[2-(biphenyl-4-yl)benzothiazole-N,C{sup 2}′]iridium(III) (acetylacetonate) [(4Phbt){sub 2}Ir(acac)], were fabricated. With the heavily doped emissive layer (EML) of 4,4′-N,N′-dicarbazolylbiphenyl (CBP): (4Phbt){sub 2}Ir(acac) in a wide and easily controlled dopant concentration range from 12 wt% to 24 wt%, a maximum power efficiency of 29 lm/W and an external quantum efficiency of >16% of the PHOLEDs were obtained, implying the insensitivity of electroluminescence (EL) properties to doping concentration. Meanwhile, a maximum power efficiency of 5.0 lm/W was achieved from a non-doped device with neat (4Phbt){sub 2}Ir(acac) as the EML, indicating a superior property of self-quenching resistance. The mechanism of direct exciton formation, in which exciton-formation regions are distributed throughout the EML, is responsible for the significant alleviation of triplet–triplet annihilation and superior EL performance. - Highlights: • Highly efficient and concentration-insensitive PHOLEDs were obtained. • The high efficiency of non-doped PHOLEDs indicated a quenching-resistant property. • The independence of EL spectra on doping concentration was observed. • The heavily doped devices were dominated by mechanism of direct exciton formation.

Efficiency and reliability improvement in wind turbine converters by grid converter adaptive control

DEFF Research Database (Denmark)

Trintis, Ionut; Munk-Nielsen, Stig; Abrahamsen, Flemming

2013-01-01

This paper presents a control method that reduces the losses in wind turbine converters adaptively controlling the grid converter. The dc-link voltage adapts its reference based on the system state and therefore reduces the stored energy, and is therefore kept at the minimum necessary for the grid...... and generator side. Operating in this way, the electrical and thermal stress factors are decreased on the power electronic devices, increasing their lifetime. The simulation results using this method show efficiency increase and devices temperature cycles slightly decreased. Experimental results on a wind...... turbine power stack shows efficiency increase in the high power region....

Photon-number-resolving SSPDs with system detection efficiency over 50% at telecom range

Science.gov (United States)

Zolotov, P.; Divochiy, A.; Vakhtomin, Yu.; Moshkova, M.; Morozov, P.; Seleznev, V.; Smirnov, K.

2018-02-01

We used technology of making high-efficiency superconducting single-photon detectors as a basis for improvement of photon-number-resolving devices. By adding optical cavity and using an improved NbN superconducting film, we enhanced previously reported system detection efficiency at telecom range for such detectors. Our results show that implementation of optical cavity helps to develop four-section device with quantum efficiency over 50% at 1.55 µm. Performed experimental studies of detecting multi-photon optical pulses showed irregularities over defining multi-photon through single-photon quantum efficiency.

Metal/Semiconductor and Transparent Conductor/Semiconductor Heterojunctions in High Efficient Photoelectric Devices: Progress and Features

Directory of Open Access Journals (Sweden)

M. Melvin David Kumar

2014-01-01

Full Text Available Metal/semiconductor and transparent conductive oxide (TCO/semiconductor heterojunctions have emerged as an effective modality in the fabrication of photoelectric devices. This review is following a recent shift toward the engineering of TCO layers and structured Si substrates, incorporating metal nanoparticles for the development of next-generation photoelectric devices. Beneficial progress which helps to increase the efficiency and reduce the cost, has been sequenced based on efficient technologies involved in making novel substrates, TCO layers, and electrodes. The electrical and optical properties of indium tin oxide (ITO and aluminum doped zinc oxide (AZO thin films can be enhanced by structuring the surface of TCO layers. The TCO layers embedded with Ag nanoparticles are used to enhance the plasmonic light trapping effect in order to increase the energy harvesting nature of photoelectric devices. Si nanopillar structures which are fabricated by photolithography-free technique are used to increase light-active surface region. The importance of the structure and area of front electrodes and the effect of temperature at the junction are the value added discussions in this review.

High performance yellow organic electroluminescent devices by doping iridium(III) complex into host materials with stepwise energy levels

Energy Technology Data Exchange (ETDEWEB)

Cui, Rongzhen; Zhou, Liang, E-mail: zhoul@ciac.ac.cn; Jiang, Yunlong; Li, Yanan; Zhao, Xuesen; Zhang, Hongjie, E-mail: hongjie@ciac.ac.cn

2015-10-15

In this work, we aim to further improve the electroluminescent (EL) performances of a yellow light-emitting iridium(III) complex by designing double light-emitting layers (EMLs) devices having stepwise energy levels. Compared with single-EML devices, these designed double-EML devices showed improved EL efficiency and brightness attributed to better balance in carriers. In addition, the stepwise distribution in energy levels of host materials is instrumental in broadening the recombination zone, thus delaying the roll-off of EL efficiency. Based on the investigation of carriers' distribution, device structure was further optimized by adjusting the thickness of deposited layers. Finally, yellow EL device (Commission Internationale de l'Eclairage (CIE) coordinates of (0.446, 0.542)) with maximum current efficiency, power efficiency and brightness up to 78.62 cd/A (external quantum efficiency (EQE) of 21.1%), 82.28 lm/W and 72,713 cd/m{sup 2}, respectively, was obtained. Even at the high brightness of 1000 cd/m{sup 2}, EL efficiency as high as 65.54 cd/A (EQE=17.6%) can be retained. - Highlights: • Yellow electroluminescent devices were designed and fabricated. • P-type and n-type materials having stepwise energy levels were chosen as host materials. • Better balance of holes and electrons causes the enhanced efficiencies. • Improved carriers' trapping suppresses the emission of host material.

Improving Light Extraction of Organic Light-Emitting Devices by Attaching Nanostructures with Self-Assembled Photonic Crystal Patterns

Directory of Open Access Journals (Sweden)

Kai-Yu Peng

2014-01-01

Full Text Available A single-monolayered hexagonal self-assembled photonic crystal (PC pattern fabricated onto polyethylene terephthalate (PET films by using simple nanosphere lithography (NSL method has been demonstrated in this research work. The patterned nanostructures acted as a scattering medium to extract the trapped photons from substrate mode of optical-electronic device for improving the overall external quantum efficiency of the organic light-emitting diodes (OLEDs. With an optimum latex concentration, the distribution of self-assembled polystyrene (PS nanosphere patterns on PET films can be easily controlled by adjusting the rotation speed of spin-coater. After attaching the PS nanosphere array brightness enhancement film (BEF sheet as a photonic crystal pattern onto the device, the luminous intensity of OLEDs in the normal viewing direction is 161% higher than the one without any BEF attachment. The electroluminescent (EL spectrum of OLEDs with PS patterned BEF attachment also showed minor color offset and superior color stabilization characteristics, and thus it possessed the potential applications in all kinds of display technology and solid-state optical-electronic devices.

High Quantum Efficiency OLED Lighting Systems

Energy Technology Data Exchange (ETDEWEB)

Shiang, Joseph [General Electric (GE) Global Research, Fairfield, CT (United States)

2011-09-30

The overall goal of the program was to apply improvements in light outcoupling technology to a practical large area plastic luminaire, and thus enable the product vision of an extremely thin form factor high efficiency large area light source. The target substrate was plastic and the baseline device was operating at 35 LPW at the start of the program. The target LPW of the program was a >2x improvement in the LPW efficacy and the overall amount of light to be delivered was relatively high 900 lumens. Despite the extremely difficult challenges associated with scaling up a wet solution process on plastic substrates, the program was able to make substantial progress. A small molecule wet solution process was successfully implemented on plastic substrates with almost no loss in efficiency in transitioning from the laboratory scale glass to large area plastic substrates. By transitioning to a small molecule based process, the LPW entitlement increased from 35 LPW to 60 LPW. A further 10% improvement in outcoupling efficiency was demonstrated via the use of a highly reflecting cathode, which reduced absorptive loss in the OLED device. The calculated potential improvement in some cases is even larger, ~30%, and thus there is considerable room for optimism in improving the net light coupling efficacy, provided absorptive loss mechanisms are eliminated. Further improvements are possible if scattering schemes such as the silver nanowire based hard coat structure are fully developed. The wet coating processes were successfully scaled to large area plastic substrate and resulted in the construction of a 900 lumens luminaire device.

Tariff-based incentives for improving coal-power-plant efficiencies in India

International Nuclear Information System (INIS)

Chikkatur, Ananth P.; Sagar, Ambuj D.; Abhyankar, Nikit; Sreekumar, N.

2007-01-01

Improving the efficiency of coal-based power plants plays an important role in improving the performance of India's power sector. It allows for increased consumer benefits through cost reduction, while enhancing energy security and helping reduce local and global pollution through more efficient coal use. A focus on supply-side efficiency also complements other ongoing efforts on end-use efficiency. The recent restructuring of the Indian electricity sector offers an important route to improving power plant efficiency, through regulatory mechanisms that allow for an independent tariff setting process for bulk purchases of electricity from generators. Current tariffs based on normative benchmarks for performance norms are hobbled by information asymmetry (where regulators do not have access to detailed performance data). Hence, we propose a new incentive scheme that gets around the asymmetry problem by setting performance benchmarks based on actual efficiency data, rather than on a normative basis. The scheme provides direct tariff-based incentives for efficiency improvements, while benefiting consumers by reducing electricity costs in the long run. This proposal might also be useful for regulators in other countries to incorporate similar incentives for efficiency improvement in power generation

Highly Efficient and Reproducible Nonfullerene Solar Cells from Hydrocarbon Solvents

KAUST Repository

Wadsworth, Andrew; Ashraf, Raja; Abdelsamie, Maged; Pont, Sebastian; Little, Mark; Moser, Maximilian; Hamid, Zeinab; Neophytou, Marios; Zhang, Weimin; Amassian, Aram; Durrant, James R.; Baran, Derya; McCulloch, Iain

2017-01-01

With chlorinated solvents unlikely to be permitted for use in solution-processed organic solar cells in industry, there must be a focus on developing nonchlorinated solvent systems. Here we report high-efficiency devices utilizing a low-bandgap donor polymer (PffBT4T-2DT) and a nonfullerene acceptor (EH-IDTBR) from hydrocarbon solvents and without using additives. When mesitylene was used as the solvent, rather than chlorobenzene, an improved power conversion efficiency (11.1%) was achieved without the need for pre- or post-treatments. Despite altering the processing conditions to environmentally friendly solvents and room-temperature coating, grazing incident X-ray measurements confirmed that active layers processed from hydrocarbon solvents retained the robust nanomorphology obtained with hot-processed chlorinated solvents. The main advantages of hydrocarbon solvent-processed devices, besides the improved efficiencies, were the reproducibility and storage lifetime of devices. Mesitylene devices showed better reproducibility and shelf life up to 4000 h with PCE dropping by only 8% of its initial value.

Highly Efficient and Reproducible Nonfullerene Solar Cells from Hydrocarbon Solvents

KAUST Repository

Wadsworth, Andrew

2017-06-01

With chlorinated solvents unlikely to be permitted for use in solution-processed organic solar cells in industry, there must be a focus on developing nonchlorinated solvent systems. Here we report high-efficiency devices utilizing a low-bandgap donor polymer (PffBT4T-2DT) and a nonfullerene acceptor (EH-IDTBR) from hydrocarbon solvents and without using additives. When mesitylene was used as the solvent, rather than chlorobenzene, an improved power conversion efficiency (11.1%) was achieved without the need for pre- or post-treatments. Despite altering the processing conditions to environmentally friendly solvents and room-temperature coating, grazing incident X-ray measurements confirmed that active layers processed from hydrocarbon solvents retained the robust nanomorphology obtained with hot-processed chlorinated solvents. The main advantages of hydrocarbon solvent-processed devices, besides the improved efficiencies, were the reproducibility and storage lifetime of devices. Mesitylene devices showed better reproducibility and shelf life up to 4000 h with PCE dropping by only 8% of its initial value.

On the Properties and Design of Organic Light-Emitting Devices

Science.gov (United States)

Erickson, Nicholas C.

Organic light-emitting devices (OLEDs) are attractive for use in next-generation display and lighting technologies. In display applications, OLEDs offer a wide emission color gamut, compatibility with flexible substrates, and high power efficiencies. In lighting applications, OLEDs offer attractive features such as broadband emission, high-performance, and potential compatibility with low-cost manufacturing methods. Despite recent demonstrations of near unity internal quantum efficiencies (photons out per electron in), OLED adoption lags conventional technologies, particularly in large-area displays and general lighting applications. This thesis seeks to understand the optical and electronic properties of OLED materials and device architectures which lead to not only high peak efficiency, but also reduced device complexity, high efficiency under high excitation, and optimal white-light emission. This is accomplished through the careful manipulation of organic thin film compositions fabricated via vacuum thermal evaporation, and the introduction of a novel device architecture, the graded-emissive layer (G-EML). This device architecture offers a unique platform to study the electronic properties of varying compositions of organic semiconductors and the resulting device performance. This thesis also introduces an experimental technique to measure the spatial overlap of electrons and holes within an OLED's emissive layer. This overlap is an important parameter which is affected by the choice of materials and device design, and greatly impacts the operation of the OLED at high excitation densities. Using the G-EML device architecture, OLEDs with improved efficiency characteristics are demonstrated, achieving simultaneously high brightness and high efficiency.

The Multiple Benefits of Measures to Improve Energy Efficiency

DEFF Research Database (Denmark)

Puig, Daniel; Farrell, Timothy Clifford

Understanding the barriers to, and enablers for, energy efficiency requires targeted information and analysis. This report is a summary of four detailed studies providing new insights on how to promote efficiency in selected priority areas. It complements initiatives such as the so-called energy...... efficiency accelerators, which seek to increase the uptake of selected technologies, as well as the work of many other institutions committed to improving energy efficiency. The modelling estimates and the case studies presented in this report illustrate that, while significant progress has already been...... achieved, the case for accelerating energy efficiency action is strong. Key highlights include: • At the global level, energy efficiency improvements would account for between 2.6 and 3.3 Gt CO2e of the reductions in 2030, equivalent to between 23 and 26 percent of the overall reductions achieved...

Potentials and policy implications of energy and material efficiency improvement

Energy Technology Data Exchange (ETDEWEB)

Worrell, Ernst; Levine, Mark; Price, Lynn; Martin, Nathan; van den Broek, Richard; Block, Kornelis

1997-01-01

There is a growing awareness of the serious problems associated with the provision of sufficient energy to meet human needs and to fuel economic growth world-wide. This has pointed to the need for energy and material efficiency, which would reduce air, water and thermal pollution, as well as waste production. Increasing energy and material efficiency also have the benefits of increased employment, improved balance of imports and exports, increased security of energy supply, and adopting environmentally advantageous energy supply. A large potential exists for energy savings through energy and material efficiency improvements. Technologies are not now, nor will they be, in the foreseeable future, the limiting factors with regard to continuing energy efficiency improvements. There are serious barriers to energy efficiency improvement, including unwillingness to invest, lack of available and accessible information, economic disincentives and organizational barriers. A wide range of policy instruments, as well as innovative approaches have been tried in some countries in order to achieve the desired energy efficiency approaches. These include: regulation and guidelines; economic instruments and incentives; voluntary agreements and actions, information, education and training; and research, development and demonstration. An area that requires particular attention is that of improved international co-operation to develop policy instruments and technologies to meet the needs of developing countries. Material efficiency has not received the attention that it deserves. Consequently, there is a dearth of data on the qualities and quantities for final consumption, thus, making it difficult to formulate policies. Available data, however, suggest that there is a large potential for improved use of many materials in industrialized countries.

InP/ZnSe/ZnS core-multishell quantum dots for improved luminescence efficiency

Science.gov (United States)

Greco, Tonino; Ippen, Christian; Wedel, Armin

2012-04-01

Semiconductor quantum dots (QDs) exhibit unique optical properties like size-tunable emission color, narrow emission peak, and high luminescence efficiency. QDs are therefore investigated towards their application in light-emitting devices (QLEDs), solar cells, and for bio-imaging purposes. In most cases QDs made from cadmium compounds like CdS, CdSe or CdTe are studied because of their facile and reliable synthesis. However, due to the toxicity of Cd compounds and the corresponding regulation (e.g. RoHS directive in Europe) these materials are not feasible for customer applications. Indium phosphide is considered to be the most promising alternative because of the similar band gap (InP 1.35 eV, CdSe 1.73 eV). InP QDs do not yet reach the quality of CdSe QDs, especially in terms of photoluminescence quantum yield and peak width. Typically, QDs are coated with another semiconductor material of wider band gap, often ZnS, to passivate surface defects and thus improve luminescence efficiency. Concerning CdSe QDs, multishell coatings like CdSe/CdS/ZnS or CdSe/ZnSe/ZnS have been shown to be advantageous due to the improved compatibility of lattice constants. Here we present a method to improve the luminescence efficiency of InP QDs by coating a ZnSe/ZnS multishell instead of a ZnS single shell. ZnSe exhibits an intermediate lattice constant of 5.67 Å between those of InP (5.87 Å) and ZnS (5.41 Å) and thus acts as a wetting layer. As a result, InP/ZnSe/ZnS is introduced as a new core-shell quantum dot material which shows improved photoluminescence quantum yield (up to 75 %) compared to the conventional InP/ZnS system.

Strategies for increasing the efficiency of heterojunction organic solar cells: material selection and device architecture.

Science.gov (United States)

Heremans, Paul; Cheyns, David; Rand, Barry P

2009-11-17

Thin-film blends or bilayers of donor- and acceptor-type organic semiconductors form the core of heterojunction organic photovoltaic cells. Researchers measure the quality of photovoltaic cells based on their power conversion efficiency, the ratio of the electrical power that can be generated versus the power of incident solar radiation. The efficiency of organic solar cells has increased steadily in the last decade, currently reaching up to 6%. Understanding and combating the various loss mechanisms that occur in processes from optical excitation to charge collection should lead to efficiencies on the order of 10% in the near future. In organic heterojunction solar cells, the generation of photocurrent is a cascade of four steps: generation of excitons (electrically neutral bound electron-hole pairs) by photon absorption, diffusion of excitons to the heterojunction, dissociation of the excitons into free charge carriers, and transport of these carriers to the contacts. In this Account, we review our recent contributions to the understanding of the mechanisms that govern these steps. Starting from archetype donor-acceptor systems of planar small-molecule heterojunctions and solution-processed bulk heterojunctions, we outline our search for alternative materials and device architectures. We show that non-planar phthalocynanines have appealing absorption characteristics but also have reduced charge carrier transport. As a result, the donor layer needs to be ultrathin, and all layers of the device have to be tuned to account for optical interference effects. Using these optimization techniques, we illustrate cells with 3.1% efficiency for the non-planar chloroboron subphthalocyanine donor. Molecules offering a better compromise between absorption and carrier mobility should allow for further improvements. We also propose a method for increasing the exciton diffusion length by converting singlet excitons into long-lived triplets. By doping a polymer with a

Efficient fluorescent red, green, and blue organic light-emitting devices with a blue host of spirobifluorene derivative

Energy Technology Data Exchange (ETDEWEB)

Lee, R.-H. [Department of Chemical and Material Engineering, National Yunlin University of Science and Technology, Yunlin 640, Taiwan (China)], E-mail: lerongho@yuntech.edu.tw; Huang, Y.-W.; Wang, Y.-Y. [Department of Chemical and Material Engineering, National Yunlin University of Science and Technology, Yunlin 640, Taiwan (China); Chang, H.-Y. [EChem Hightech CO., LTD, Hsin-Chu Industrial Park, Hu-Kou, Hsin-Chu, Taiwan (China)

2008-06-02

Efficient fluorescent blue, green, and red (RGB) organic light-emitting devices (OLEDs) were fabricated using a blue host material of pyrimidine-containing spirobifluorene derivative 2,7-bis[2-(4-tert-butylphenyl)pyrimidine-5-yl]-9,9'-spirobifluorene (TBPSF) doped with blue dye perylene, green dye 10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H, 11H-benzo[l] pyrano[6,7,8-ij] quinolizin-11-one (C545T), and red dye 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran (DCJTB), respectively. The brightness and current efficiency of the perylene doped blue device reached 10117 cd/m{sup 2} and 2.97 cd/A. Green emission of the C545T doped device reached 8500 cd/m{sup 2} and 13.0 cd/A. Red emission of the DCJTB doped device can be as high as 9000 cd/m{sup 2} and 2.0 cd/A, respectively. High color purity of the blue (Commission Internationale de L'Eclairage (CIE{sub x,y}) coordinates (CIE, x = 0.27, y = 0.24)), green (CIE, x = 0.19, y = 0.63) and red (CIE, x = 0.62, y = 0.37) emissions were achieved for RGB dyes doped TBPSF OLEDs. High brightness, large current efficiency, and good color purity of TBPSF-based RGB OLEDs were obtained by the configuration optimization device, such as inserting the hole and electron-injection materials, and suitable dopant content and light emitting layer thickness.

Optimized pulsed write schemes improve linearity and write speed for low-power organic neuromorphic devices

Science.gov (United States)

Keene, Scott T.; Melianas, Armantas; Fuller, Elliot J.; van de Burgt, Yoeri; Talin, A. Alec; Salleo, Alberto

2018-06-01

Neuromorphic devices are becoming increasingly appealing as efficient emulators of neural networks used to model real world problems. However, no hardware to date has demonstrated the necessary high accuracy and energy efficiency gain over CMOS in both (1) training via backpropagation and (2) in read via vector matrix multiplication. Such shortcomings are due to device non-idealities, particularly asymmetric conductance tuning in response to uniform voltage pulse inputs. Here, by formulating a general circuit model for capacitive ion-exchange neuromorphic devices, we show that asymmetric nonlinearity in organic electrochemical neuromorphic devices (ENODes) can be suppressed by an appropriately chosen write scheme. Simulations based upon our model suggest that a nonlinear write-selector could reduce the switching voltage and energy, enabling analog tuning via a continuous set of resistance states (100 states) with extremely low switching energy (~170 fJ · µm‑2). This work clarifies the pathway to neural algorithm accelerators capable of parallelism during both read and write operations.

Improved performances of red organic light-emitting devices by co-doping a rubrene derivative and DCJTB into tris-(8-hydroxyquinoline) aluminum host

Energy Technology Data Exchange (ETDEWEB)

Li Tianle [Physics Department, School of Science, Maoming University, Maoming 525000 (China); Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Li Wenlian, E-mail: wllioel@yahoo.com.c [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Li Xiao [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Chu Bei, E-mail: beichubox@hotmail.co [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Su Zisheng; Han Liangliang; Chen Yiren [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Hu Zhizhi; Zhang Zhiqiang [Optic Photo-Electronic Materials and Research Development Center, Liaoning University of Science and Technology, Anshan 114044 (China)

2010-10-15

Performances of red organic light-emitting device were improved by co-doping 2-formyl-5,6,11,12-tetraphenylnaphthacene (2FRb) and 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetra-methyljulolidyl-9-enyl) -4H-pyran (DCJTB) in tris-(8-hydroxyquinoline) aluminum (Alq{sub 3}) host as the emitting layer. The device with 1 wt% DCJTB and 2.4 w% 2FRb in Alq{sub 3} host gave a saturated red emission with CIE chromaticity coordinates of (0.65, 0.35) and a maximum current efficiency as high as 6.45 cd/A, which are 2 and 2.4 fold larger than that of the device with 1 wt% DCJTB (3.28 cd/A) in Alq{sub 3} host and the device with 2.4 wt% 2FRb (2.72 cd/A) in Alq{sub 3} host at the current density of 20 mA/cm{sup 2}, respectively. The improvement could be attributed to the effective utilization of host energy by both energy transfer and trapping in the electroluminescence process and the depression of concentration quenching between the dopants molecules.

The improving efficiency frontier of religious not-for-profit hospitals.

Science.gov (United States)

Harrison, Jeffrey P; Sexton, Christopher

2006-01-01

By using data-envelopment analysis (DEA), this study evaluates the efficiency of religious not-for-profit hospitals. Hospital executives, healthcare policy makers, taxpayers, and other stakeholders benefit from studies that improve hospital efficiency. Results indicate that overall efficiency in religious hospitals improved from 72% in 1998 to 74% in 2001. What is more important is that the number of religious hospitals operating on the efficiency frontier increased from 40 in 1998 to 47 in 2001. This clearly documents that religious hospitals are becoming more efficient in the management of resources. From a policy perspective, this study highlights the economic importance of encouraging increased efficiency throughout the healthcare industry.

Evaluation efficiency for mobile as discharge measurement device for partially filled circular channel

Directory of Open Access Journals (Sweden)

I.M.H. Rashwan

2013-06-01

Full Text Available Discharge measurement is an important step in engineering applications such as sewerage system, irrigation and drainage system. Mobile flume is a simple and low-cost discharge measuring device constructed of two pieces of pipes, one installed vertically inside the other. The circular mobile flume depends on the concept of developing a contracted zone to have a control section. To evaluate the efficiency of this type of device mathematical and experimental studies are presented. Specific energy, discharge and Froude number equations are used to develop mathematical model. Experimental work is carried out to measure the discharge values corresponding to the specific energy values. The experimental data is used to evaluate the mobile flume as a device to measure discharge. A new equation for the discharge coefficient is presented. This equation can be used to determined accurate discharge with knowing the contraction ratio and measured specific energy.

Very high efficiency phosphorescent organic light-emitting devices by using rough indium tin oxide

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yingjie; Aziz, Hany, E-mail: h2aziz@uwaterloo.ca [Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada)

2014-07-07

The efficiency of organic light-emitting devices (OLEDs) is shown to significantly depend on the roughness of the indium tin oxide (ITO) anode. By using rougher ITO, light trapped in the ITO/organic wave-guided mode can be efficiently extracted, and a light outcoupling enhancement as high as 40% is achieved. Moreover, contrary to expectations, the lifetime of OLEDs is not affected by ITO roughness. Finally, an OLED employing rough ITO anode that exhibits a current efficiency of 56 cd/A at the remarkably high brightness of 10{sup 5} cd/m{sup 2} is obtained. This represents the highest current efficiency at such high brightness to date for an OLED utilizing an ITO anode, without any external light outcoupling techniques. The results demonstrate the significant efficiency benefits of using ITO with higher roughness in OLEDs.

Very high efficiency phosphorescent organic light-emitting devices by using rough indium tin oxide

International Nuclear Information System (INIS)

Zhang, Yingjie; Aziz, Hany

2014-01-01

The efficiency of organic light-emitting devices (OLEDs) is shown to significantly depend on the roughness of the indium tin oxide (ITO) anode. By using rougher ITO, light trapped in the ITO/organic wave-guided mode can be efficiently extracted, and a light outcoupling enhancement as high as 40% is achieved. Moreover, contrary to expectations, the lifetime of OLEDs is not affected by ITO roughness. Finally, an OLED employing rough ITO anode that exhibits a current efficiency of 56 cd/A at the remarkably high brightness of 10 5  cd/m 2 is obtained. This represents the highest current efficiency at such high brightness to date for an OLED utilizing an ITO anode, without any external light outcoupling techniques. The results demonstrate the significant efficiency benefits of using ITO with higher roughness in OLEDs.

Report on achievements in fiscal 1999 on international model project for energy consumption efficiency improvement. 'Model project to enhance boiler and turbine efficiency'; 1999 nendo kokusai energy shohi koritsuka tou moderu jigyo seika hokoku. Boira gasu tabin koritsu kojo moderu jigyo

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

With an objective to save energy, reduce electric power generation cost, and reduce CO2 exhaust in Indonesia, the Japanese energy saving technologies were transferred to the Muara-Karang Power Station in Indonesia as the object of the project. This paper reports the achievement in fiscal 1999. The target was set to reducing the power generation unit requirement (heat consumption ratio, kcal/kWh) by 1% by improving such constitutional devices as water condensers and air pre-heaters. Further improvements were planned by introducing the thermal efficiency control program. The subject fiscal year has performed data acquisition from the site surveys, investigations on related technologies, and detailed designs for site construction and effect identification. Also having been carried out based on the result of the detailed designs was partial fabrication of members and parts necessary for facility modification such as for small tubes for water condensers made of new materials. Furthermore, the Indonesian engineers were accepted for the purpose of transferring the thermal efficiency management methods, and the maintenance and control technologies for devices being the objects of the facility modification related to the boiler and turbine efficiency improvement. (NEDO)

SiC for more efficiency

Energy Technology Data Exchange (ETDEWEB)

Wilming, Wilhelm

2013-07-01

In the past, inverter manufacturers have succeeded in improving the degree of efficiency of their devices. However, the power electronics used until now, with the silicon-based electronic switches, are increasingly reaching the limits of their physical capacity. The semiconductor silicon carbide could push these limits further upwards, enabling degrees of efficiency of over 99 % to become the standard. (orig.)

Improving STEM Undergraduate Education with Efficient Learning Design

DEFF Research Database (Denmark)

Godsk, Mikkel

2018-01-01

The project investigates the potential of Learning Design for efficiently improving STEM undergraduate education with technology. In order to investigate this potential, the project consists of two main studies at Aarhus University: a study of the perspectives of the main stakeholders on Learning...... Design uptake. The project concludes that it is possible to improve STEM undergraduate education with Learning Design for technology-enhanced learning efficiently and that Efficient Learning Design provides a useful concept for qualifying educational decisions....... provided by technology-enhanced learning based on Learning Design, and in particular students’ learning was of a high common interest. However, only the educators were directly interested in Learning Design and its support for design, reuse in their practice and to inform pedagogy. A holistic concept...

An Analysis of Sources of Technological Change in Efficiency Improvement of Fluorescent Lamp Systems

Science.gov (United States)

Imanaka, Takeo

In Japan, energy efficient fluorescent lamp systems which use “rare-earth phosphors” and “electronic ballasts” have shown rapid diffusion since 1990s. This report investigated sources of technological change in the efficiency improvement of fluorescent lamp systems: (i) Fluorescent lamp and luminaires have been under steady technological development for getting more energy efficient lighting and the concepts to achieve high efficiency had been found in such activities; however, it took long time until they realized and become widely used; (ii) Electronic ballasts and rare-earth phosphors add fluorescent lamp systems not only energy efficiency but also various values such as compactness, lightweight, higher output, and better color rendering properties, which have also been expected and have induced research and development (R&D) (iii) Affordable electronic ballasts are realized by the new technology “power MOSFET” which is based on IC technologies and has been developed for large markets of information and communication technologies and mobile devices; and (iv) Rare-earth phosphors became available after rare-earth industries developed for the purpose of supplying rare-earth phosphors for color television. In terms of sources of technological change, (i) corresponds to “R&D” aiming at the particular purpose i.e. energy efficiency in this case, on the other hand, (ii), (iii), and (iv) correspond to “spillovers” from activities aiming at other purposes. This case exhibits an actual example in which “spillovers” were the critical sources of technological change in energy technology.

Copper Antimony Chalcogenide Thin Film PV Device Development

Energy Technology Data Exchange (ETDEWEB)

Welch, Adam W.; Baranowski, Lauryn L.; de Souza Lucas, Francisco Willian; Toberer, Eric S.; Wolden, Colin A.; Zakutayev, Andriy

2015-06-14

Emerging ternary chalcogenide thin film solar cell technologies, such as CuSbS2 and CuSbSe2, have recently attracted attention as simpler alternatives to quaternary Cu2ZnSnS4 (CZTS). Despite suitable photovoltaic properties, the initial energy conversion efficiency of CuSbS2 is rather low (0.3%). Here, we report on our progress towards improving the efficiency of CuSbS2 solar cells using a high throughput approach. The combinatorial methodology quickly results in baseline solar cell prototypes with 0.6% efficiency, and then modification of the back contact architecture leads to 1% PV devices. We then translate the optimal CuSbS2 synthesis parameters to CuSbSe2 devices, which show 3% efficiencies.

Steam Pressure-Reducing Station Safety and Energy Efficiency Improvement Project

Energy Technology Data Exchange (ETDEWEB)

Lower, Mark D [ORNL; Christopher, Timothy W [ORNL; Oland, C Barry [ORNL

2011-06-01

The Facilities and Operations (F&O) Directorate is sponsoring a continuous process improvement (CPI) program. Its purpose is to stimulate, promote, and sustain a culture of improvement throughout all levels of the organization. The CPI program ensures that a scientific and repeatable process exists for improving the delivery of F&O products and services in support of Oak Ridge National Laboratory (ORNL) Management Systems. Strategic objectives of the CPI program include achieving excellence in laboratory operations in the areas of safety, health, and the environment. Identifying and promoting opportunities for achieving the following critical outcomes are important business goals of the CPI program: improved safety performance; process focused on consumer needs; modern and secure campus; flexibility to respond to changing laboratory needs; bench strength for the future; and elimination of legacy issues. The Steam Pressure-Reducing Station (SPRS) Safety and Energy Efficiency Improvement Project, which is under the CPI program, focuses on maintaining and upgrading SPRSs that are part of the ORNL steam distribution network. This steam pipe network transports steam produced at the ORNL steam plant to many buildings in the main campus site. The SPRS Safety and Energy Efficiency Improvement Project promotes excellence in laboratory operations by (1) improving personnel safety, (2) decreasing fuel consumption through improved steam system energy efficiency, and (3) achieving compliance with applicable worker health and safety requirements. The SPRS Safety and Energy Efficiency Improvement Project being performed by F&O is helping ORNL improve both energy efficiency and worker safety by modifying, maintaining, and repairing SPRSs. Since work began in 2006, numerous energy-wasting steam leaks have been eliminated, heat losses from uninsulated steam pipe surfaces have been reduced, and deficient pressure retaining components have been replaced. These improvements helped ORNL

Identification of barriers and research opportunities to improve the effective and efficient application of adjunct UVC surface disinfection in healthcare

Science.gov (United States)

Martinello, Richard A.; Miller, Shelly L.; Fabian, M. Patricia; Peccia, Jordan

2018-02-01

Healthcare associated infections (HAI) affect approximately 1 of every 25 hospitalized patients, lead to substantial morbidity and mortality, degrade patient experience and are costly. Risks for HAI are multifactorial and it is known that microbial contamination of the healthcare environment increases risk for HAI. Portable ultraviolet-C (UVC) surface disinfection as an adjunct to standard hospital disinfection has been shown to decrease both surface microbial contamination and HAI. However, there remain significant gaps in the understanding of the efficient and effective application of UVC in healthcare. Specific barriers identified are: 1) the variability in size, shape, and surface materials of hospital rooms as well as the presence of medical devices and furniture, which impacts the amount of UVC energy delivered to surfaces and its disinfection efficiency; 2) the significant resources needed to acquire and efficiently use UVC equipment and achieve the desired patient benefits- a particular challenge for complex healthcare facilities with limited operating margins; and 3) the lack of implementation guidance and industry standard methods for measuring the UVC output and antimicrobial effects from the multiple commercial UVC options available. An improved understanding of the efficient and effective use of UVC surface disinfection in healthcare and the implementation of standard device industry metrics may lead to increased use and decrease the burden of HAI.

A Game-Theoretical Approach for Spectrum Efficiency Improvement in Cloud-RAN

Directory of Open Access Journals (Sweden)

Zhuofu Zhou

2016-01-01

Full Text Available As tremendous mobile devices access to the Internet in the future, the cells which can provide high data rate and more capacity are expected to be deployed. Specifically, in the next generation of mobile communication 5G, cloud computing is supposed to be applied to radio access network. In cloud radio access network (Cloud-RAN, the traditional base station is divided into two parts, that is, remote radio heads (RRHs and base band units (BBUs. RRHs are geographically distributed and densely deployed, so as to achieve high data rate and low latency. However, the ultradense deployment inevitably deteriorates spectrum efficiency due to the severer intercell interference among RRHs. In this paper, the downlink spectrum efficiency can be improved through the cooperative transmission based on forming the coalitions of RRHs. We formulate the problem as a coalition formation game in partition form. In the process of coalition formation, each RRH can join or leave one coalition to maximize its own individual utility while taking into account the coalition utility at the same time. Moreover, the convergence and stability of the resulting coalition structure are studied. The numeric simulation result demonstrates that the proposed approach based on coalition formation game is superior to the noncooperative method in terms of the aggregate coalition utility.

DTU International Energy Report 2012: Energy efficiency improvements

DEFF Research Database (Denmark)

Increased energy efficiency can reduce global CO2 emissions over the period to 2050 with up to 25%. On the top of that large profits can be gained for very little investment. Energy efficiency improvements can save investment in new energy infrastructure, cut fuel costs, increase competitiveness...... and increase consumer welfare. Thus, it is natural for DTU International Energy Report 2012 to take up this issue and analyze the global, regional and national challenges in exploiting energy efficiency and promote research and development in energy efficiency....

RADIO FREQUENCY IDENTIFICATION DEVICES: EFFECTIVENESS IN IMPROVING SAFEGUARDS AT GAS-CENTRIFUGE URANIUM-ENRICHMENT PLANTS

International Nuclear Information System (INIS)

JOE, J.

2007-01-01

Recent advances in radio frequency identification devices (RFIDs) have engendered a growing interest among international safeguards experts. Potentially, RFIDs could reduce inspection work, viz. the number of inspections, number of samples, and duration of the visits, and thus improve the efficiency and effectiveness of international safeguards. This study systematically examined the applications of RFIDs for IAEA safeguards at large gas-centrifuge enrichment plants (GCEPs). These analyses are expected to help identify the requirements and desirable properties for RFIDs, to provide insights into which vulnerabilities matter most, and help formulate the required assurance tests. This work, specifically assesses the application of RFIDs for the ''Option 4'' safeguards approach, proposed by Bruce Moran, U. S. Nuclear Regulatory Commission (NRC), for large gas-centrifuge uranium-enrichment plants. The features of ''Option 4'' safeguards include placing RFIDs on all feed, product and tails (F/P/T) cylinders, along with WID readers in all FP/T stations and accountability scales. Other features of Moran's ''Option 4'' are Mailbox declarations, monitoring of load-cell-based weighing systems at the F/P/T stations and accountability scales, and continuous enrichment monitors. Relevant diversion paths were explored to evaluate how RFIDs improve the efficiency and effectiveness of safeguards. Additionally, the analysis addresses the use of RFIDs in conjunction with video monitoring and neutron detectors in a perimeter-monitoring approach to show that RFIDs can help to detect unidentified cylinders

Improved vascularization of planar membrane diffusion devices following continuous infusion of vascular endothelial growth factor.

Science.gov (United States)

Trivedi, N; Steil, G M; Colton, C K; Bonner-Weir, S; Weir, G C

2000-01-01

Improving blood vessel formation around an immunobarrier device should improve the survival of the encapsulated tissue. In the present study we investigated the formation of new blood vessels around a planar membrane diffusion device (the Baxter Theracyte System) undergoing a continuous infusion of vascular endothelial growth factor through the membranes and into the surrounding tissue. Each device (20 microl) had both an inner immunoisolation membrane and an outer vascularizing membrane. Human recombinant vascular endothelial growth factor-165 was infused at 100 ng/day (low dose: n = 6) and 500 ng/day (high dose: n = 7) for 10 days into devices implanted s.c. in Sprague-Dawley rats; noninfused devices transplanted for an identical period were used as controls (n = 5). Two days following the termination of VEGF infusion, devices were loaded with 20 microl of Lispro insulin (1 U/kg) and the kinetics of insulin release from the lumen of the device was assessed. Devices were then explanted and the number of blood vessels (capillary and noncapillary) was quantified using morphometry. High-dose vascular endothelial growth factor infusion resulted in two- to threefold more blood vessels around the device than that obtained with the noninfused devices and devices infused with low-dose vascular endothelial growth factor. This increase in the number of blood vessels was accompanied by a modest increase in insulin diffusion from the device in the high-dose vascular endothelial growth factor infusion group. We conclude that vascular endothelial growth factor can be used to improve blood vessel formation adjacent to planar membrane diffusion devices.

Improvement of light harvesting and device performance of dye-sensitized solar cells using rod-like nanocrystal TiO2 overlay coating on TiO2 nanoparticle working electrode

International Nuclear Information System (INIS)

Liu, Xueyang; Fang, Jian; Gao, Mei; Wang, Hongxia; Yang, Weidong; Lin, Tong

2015-01-01

Novel TiO 2 single crystalline nanorods were synthesized by electrospinning and hydrothermal treatment. The role of the TiO 2 nanorods on TiO 2 nanoparticle electrode in improvement of light harvesting and photovoltaic properties of dye-sensitized solar cells (DSSCs) was examined. Although the TiO 2 nanorods had lower dye loading than TiO 2 nanoparticle, they showed higher light utilization behaviour. Electron transfer in TiO 2 nanorods received less resistance than that in TiO 2 nanoparticle aggregation. By just applying a thin layer of TiO 2 nanorods on TiO 2 nanoparticle working electrode, the DSSC device light harvesting ability and energy conversion efficiency were improved significantly. The thickness of the nanorod layer in the working electrode played an important role in determining the photovoltaic property of DSSCs. An energy conversion efficiency as high as 6.6% was found on a DSSC device with the working electrode consisting of a 12 μm think TiO 2 nanoparticle layer covered with 3 μm thick TiO 2 nanorods. The results obtained from this study may benefit further design of highly efficient DSSCs. - Highlights: • Single crystalline TiO 2 nanorods were prepared for DSSC application. • TiO 2 nanorods show effective light scattering performance. • TiO 2 nanorods have higher electron transfer efficiency than TiO 2 nanoparticles. • TiO 2 nanorods on TiO 2 nanoparticle electrode improve DSSC efficiency

A Polynomial Subset-Based Efficient Multi-Party Key Management System for Lightweight Device Networks.

Science.gov (United States)

Mahmood, Zahid; Ning, Huansheng; Ghafoor, AtaUllah

2017-03-24

Wireless Sensor Networks (WSNs) consist of lightweight devices to measure sensitive data that are highly vulnerable to security attacks due to their constrained resources. In a similar manner, the internet-based lightweight devices used in the Internet of Things (IoT) are facing severe security and privacy issues because of the direct accessibility of devices due to their connection to the internet. Complex and resource-intensive security schemes are infeasible and reduce the network lifetime. In this regard, we have explored the polynomial distribution-based key establishment schemes and identified an issue that the resultant polynomial value is either storage intensive or infeasible when large values are multiplied. It becomes more costly when these polynomials are regenerated dynamically after each node join or leave operation and whenever key is refreshed. To reduce the computation, we have proposed an Efficient Key Management (EKM) scheme for multiparty communication-based scenarios. The proposed session key management protocol is established by applying a symmetric polynomial for group members, and the group head acts as a responsible node. The polynomial generation method uses security credentials and secure hash function. Symmetric cryptographic parameters are efficient in computation, communication, and the storage required. The security justification of the proposed scheme has been completed by using Rubin logic, which guarantees that the protocol attains mutual validation and session key agreement property strongly among the participating entities. Simulation scenarios are performed using NS 2.35 to validate the results for storage, communication, latency, energy, and polynomial calculation costs during authentication, session key generation, node migration, secure joining, and leaving phases. EKM is efficient regarding storage, computation, and communication overhead and can protect WSN-based IoT infrastructure.

Modifying the organic/electrode interface in Organic Solar Cells (OSCs) and improving the efficiency of solution-processed phosphorescent Organic Light-Emitting Diodes (OLEDs)

Energy Technology Data Exchange (ETDEWEB)

Xiao, Teng [Iowa State Univ., Ames, IA (United States)

2012-01-01

Organic semiconductors devices, such as, organic solar cells (OSCs), organic light-emitting diodes (OLEDs) and organic field-effect transistors (OFETs) have drawn increasing interest in recent decades. As organic materials are flexible, light weight, and potentially low-cost, organic semiconductor devices are considered to be an alternative to their inorganic counterparts. This dissertation will focus mainly on OSCs and OLEDs. As a clean and renewable energy source, the development of OSCs is very promising. Cells with 9.2% power conversion efficiency (PCE) were reported this year, compared to < 8% two years ago. OSCs belong to the so-called third generation solar cells and are still under development. While OLEDs are a more mature and better studied field, with commercial products already launched in the market, there are still several key issues: (1) the cost of OSCs/OLEDs is still high, largely due to the costly manufacturing processes; (2) the efficiency of OSCs/OLEDs needs to be improved; (3) the lifetime of OSCs/OLEDs is not sufficient compared to their inorganic counterparts; (4) the physics models of the behavior of the devices are not satisfactory. All these limitations invoke the demand for new organic materials, improved device architectures, low-cost fabrication methods, and better understanding of device physics. For OSCs, we attempted to improve the PCE by modifying the interlayer between active layer/metal. We found that ethylene glycol (EG) treated poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (PEDOT: PSS) improves hole collection at the metal/polymer interface, furthermore it also affects the growth of the poly(3- hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) blends, making the phase segregation more favorable for charge collection. We then studied organic/inorganic tandem cells. We also investigated the effect of a thin LiF layer on the hole-collection of copper phthalocyanine (CuPc)/C70-based small molecular OSCs. A

Improving Reliability, Security, and Efficiency of Reconfigurable Hardware Systems (Habilitation)

NARCIS (Netherlands)

Ziener, Daniel

2017-01-01

In this treatise,  my research on methods to improve efficiency, reliability, and security of reconfigurable hardware systems, i.e., FPGAs, through partial dynamic reconfiguration is outlined. The efficiency of reconfigurable systems can be improved by loading optimized data paths on-the-fly on an

Fundamental understanding and development of low-cost, high-efficiency silicon solar cells

Energy Technology Data Exchange (ETDEWEB)

ROHATGI,A.; NARASIMHA,S.; MOSCHER,J.; EBONG,A.; KAMRA,S.; KRYGOWSKI,T.; DOSHI,P.; RISTOW,A.; YELUNDUR,V.; RUBY,DOUGLAS S.

2000-05-01

The overall objectives of this program are (1) to develop rapid and low-cost processes for manufacturing that can improve yield, throughput, and performance of silicon photovoltaic devices, (2) to design and fabricate high-efficiency solar cells on promising low-cost materials, and (3) to improve the fundamental understanding of advanced photovoltaic devices. Several rapid and potentially low-cost technologies are described in this report that were developed and applied toward the fabrication of high-efficiency silicon solar cells.

Gas Transfer in Cellularized Collagen-Membrane Gas Exchange Devices.

Science.gov (United States)

Lo, Justin H; Bassett, Erik K; Penson, Elliot J N; Hoganson, David M; Vacanti, Joseph P

2015-08-01

Chronic lower respiratory disease is highly prevalent in the United States, and there remains a need for alternatives to lung transplant for patients who progress to end-stage lung disease. Portable or implantable gas oxygenators based on microfluidic technologies can address this need, provided they operate both efficiently and biocompatibly. Incorporating biomimetic materials into such devices can help replicate native gas exchange function and additionally support cellular components. In this work, we have developed microfluidic devices that enable blood gas exchange across ultra-thin collagen membranes (as thin as 2 μm). Endothelial, stromal, and parenchymal cells readily adhere to these membranes, and long-term culture with cellular components results in remodeling, reflected by reduced membrane thickness. Functionally, acellular collagen-membrane lung devices can mediate effective gas exchange up to ∼288 mL/min/m(2) of oxygen and ∼685 mL/min/m(2) of carbon dioxide, approaching the gas exchange efficiency noted in the native lung. Testing several configurations of lung devices to explore various physical parameters of the device design, we concluded that thinner membranes and longer gas exchange distances result in improved hemoglobin saturation and increases in pO2. However, in the design space tested, these effects are relatively small compared to the improvement in overall oxygen and carbon dioxide transfer by increasing the blood flow rate. Finally, devices cultured with endothelial and parenchymal cells achieved similar gas exchange rates compared with acellular devices. Biomimetic blood oxygenator design opens the possibility of creating portable or implantable microfluidic devices that achieve efficient gas transfer while also maintaining physiologic conditions.

Efficiency improvement opportunities in TVs: Implications for market transformation programs

International Nuclear Information System (INIS)

Park, Won Young; Phadke, Amol; Shah, Nihar; Letschert, Virginie

2013-01-01

Televisions (TVs) account for a significant portion of residential electricity consumption and global TV shipments are expected to continue to increase. We assess the market trends in the energy efficiency of TVs that are likely to occur without any additional policy intervention and estimate that TV efficiency will likely improve by over 60% by 2015 with savings potential of 45 terawatt-hours [TW h] per year in 2015, compared to today’s technology. We discuss various energy-efficiency improvement options and evaluate the cost effectiveness of three of them. At least one of these options improves efficiency by at least 20% cost effectively beyond ongoing market trends. We provide insights for policies and programs that can be used to accelerate the adoption of efficient technologies to further capture global energy savings potential from TVs which we estimate to be up to 23 TW h per year in 2015. - Highlights: • We analyze the impact of the recent TV market transition on TV energy consumption. • We review TV technology options that could be realized in the near future. • We assess the cost-effectiveness of selected energy-efficiency improvement options. • We estimate global electricity savings potential in selected scenarios. • We discuss possible directions of market transformation programs

Field Performance versus Standard Test Condition Efficiency of Tandem Solar Cells and the Specific Case of Perovskites/Silicon Devices

KAUST Repository

Dupre, Olivier

2018-01-05

Multijunction cells may offer a cost-effective route to boost the efficiency of industrial photovoltaics. For any technology to be deployed in the field, its performance under actual operating conditions is extremely important. In this perspective, we evaluate the impact of spectrum, light intensity, and module temperature variations on the efficiency of tandem devices with crystalline silicon bottom cells with a particular focus on perovskite top cells. We consider devices with different efficiencies and calculate their energy yields using field data from Denver. We find that annual losses due to differences between operating conditions and standard test conditions are similar for single-junction and four-terminal tandem devices. The additional loss for the two-terminal tandem configuration caused by current mismatch reduces its performance ratio by only 1.7% when an optimal top cell bandgap is used. Additionally, the unusual bandgap temperature dependence of perovskites is shown to have a positive, compensating effect on current mismatch.

Dye-sensitized solar cell module realized photovoltaic and photothermal highly efficient conversion via three-dimensional printing technology

International Nuclear Information System (INIS)

Huang Qi-Zhang; Zhu Yan-Qing; Shi Ji-Fu; Wang Lei-Lei; Zhong Liu-Wen; Xu Gang

2017-01-01

Three-dimensional (3D) printing technology is employed to improve the photovoltaic and photothermal conversion efficiency of dye-sensitized solar cell (DSC) module. The 3D-printed concentrator is optically designed and improves the photovoltaic efficiency of the DSC module from 5.48% to 7.03%. Additionally, with the 3D-printed microfluidic device serving as water cooling, the temperature of the DSC can be effectively controlled, which is beneficial for keeping a high photovoltaic conversion efficiency for DSC module. Moreover, the 3D-printed microfluidic device can realize photothermal conversion with an instantaneous photothermal efficiency of 42.1%. The integrated device realizes a total photovoltaic and photothermal conversion efficiency of 49% at the optimal working condition. (paper)

Development of an efficient DC-DC SEPIC converter using wide bandgap power devices for high step-up applications

Science.gov (United States)

Al-bayati, Ali M. S.; Alharbi, Salah S.; Alharbi, Saleh S.; Matin, Mohammad

2017-08-01

A highly efficient high step-up dc-dc converter is the major requirement in the integration of low voltage renewable energy sources, such as photovoltaic panel module and fuel cell stacks, with a load or utility. This paper presents the development of an efficient dc-dc single-ended primary-inductor converter (SEPIC) for high step-up applications. Three SEPIC converters are designed and studied using different combinations of power devices: a combination based on all Si power devices using a Si-MOSFET and a Si-diode and termed as Si/Si, a combination based on a hybrid of Si and SiC power devices using the Si-MOSFET and a SiC-Schottky diode and termed as Si/SiC, and a combination based on all SiC power devices using a SiC-MOSFET and the SiC-Schottky diode and termed as SiC/SiC. The switching behavior of the Si-MOSFET and SiC-MOSFET is characterized and analyzed within the different combinations at the converter level. The effect of the diode type on the converter's overall performance is also discussed. The switching energy losses, total power losses, and the overall performance effciency of the converters are measured and reported under different switching frequencies. Furthermore, the potential of the designed converters to operate efficiently at a wide range of input voltages and output powers is studied. The analysis and results show an outstanding performance efficiency of the designed SiC/SiC based converter under a wide range of operating conditions.

Improvement in distance and near visual acuities using low vision devices in diabetic retinopathy

Directory of Open Access Journals (Sweden)

Sarika Gopalakrishnan

2017-01-01

Full Text Available Purpose: The aim of this study is to elucidate the causes and level of visual impairment (VI in patients with different pathologies of diabetic retinopathy (DR who presented to a low vision care (LVC clinic, to analyze the type of distant and near devices prescribed to them and the visual benefits thereof. Methods: A retrospective chart review was done for 100 consecutive patients with DR who were referred to the LVC clinic from June 2015 to June 2016. The reason for referral was assessed from the electronic medical records and available fundus photographs, fundus fluorescein angiograms, and optical coherence tomography images by a retina specialist. The details of low-vision devices and subsequent improvements were noted. Results: Of the 100 patients, 52% had moderate VI, 19% mild VI, 16% severe VI, and 13% had profound VI or blindness. The most commonly prescribed low vision device was half-eye spectacles (38.4%. The pathologies which had statistically significant improvement (P < 0.05 in distance vision with low vision devices were DR with disc pallor (4.4% improvement, ischemic maculopathy (11.9% improvement, and plaque of hard exudate (10.1% improvement. However, in all pathologies, there was statistically significant improvement (P < 0.05 in near vision. Conclusion: Usually, the patients with DR presented to the LVC clinic with moderate VI. The use of low vision devices can help these patients in cases where medical and surgical treatment have no or a limited role in restoring useful vision.

Improving crop nutrient efficiency through root architecture modifications.

Science.gov (United States)

Li, Xinxin; Zeng, Rensen; Liao, Hong

2016-03-01

Improving crop nutrient efficiency becomes an essential consideration for environmentally friendly and sustainable agriculture. Plant growth and development is dependent on 17 essential nutrient elements, among them, nitrogen (N) and phosphorus (P) are the two most important mineral nutrients. Hence it is not surprising that low N and/or low P availability in soils severely constrains crop growth and productivity, and thereby have become high priority targets for improving nutrient efficiency in crops. Root exploration largely determines the ability of plants to acquire mineral nutrients from soils. Therefore, root architecture, the 3-dimensional configuration of the plant's root system in the soil, is of great importance for improving crop nutrient efficiency. Furthermore, the symbiotic associations between host plants and arbuscular mycorrhiza fungi/rhizobial bacteria, are additional important strategies to enhance nutrient acquisition. In this review, we summarize the recent advances in the current understanding of crop species control of root architecture alterations in response to nutrient availability and root/microbe symbioses, through gene or QTL regulation, which results in enhanced nutrient acquisition. © 2015 Institute of Botany, Chinese Academy of Sciences.

Electric motor systems in developing countries: Opportunities for efficiency improvement

Energy Technology Data Exchange (ETDEWEB)

Meyers, S.; Monahan, P.; Lewis, P.; Greenberg, S. [Lawrence Berkeley Lab., CA (United States); Nadel, S. [American Council for an Energy-Efficient Economy, Washington, DC (United States)

1993-08-01

This report presents an overview of the current status and efficiency improvement potential of industrial motor systems in developing countries. Better management of electric motor systems is of particular relevance in developing countries, where improved efficiency can lead to increased productivity and slower growth in electricity demand. Motor systems currently consume some 65--80% of the industrial electricity in developing countries. Drawing on studies from Thailand, India, Brazil, China, Pakistan, and Costa Rica, we describe potential efficiency gains in various parts of the motor system, from the electricity delivery system through the motor to the point where useful work is performed. We report evidence of a significant electricity conservation potential. Most of the efficiency improvement methods we examine are very cost-effective from a societal viewpoint, but are generally not implemented due to various barriers that deter their adoption. Drawing on experiences in North America, we discuss a range of policies to overcome these barriers, including education, training, minimum efficiency standards, motor efficiency testing protocols, technical assistance programs, and financial incentives.

Smart portable rehabilitation devices

Directory of Open Access Journals (Sweden)

Leahey Matt

2005-07-01

Full Text Available Abstract Background The majority of current portable orthotic devices and rehabilitative braces provide stability, apply precise pressure, or help maintain alignment of the joints with out the capability for real time monitoring of the patient's motions and forces and without the ability for real time adjustments of the applied forces and motions. Improved technology has allowed for advancements where these devices can be designed to apply a form of tension to resist motion of the joint. These devices induce quicker recovery and are more effective at restoring proper biomechanics and improving muscle function. However, their shortcoming is in their inability to be adjusted in real-time, which is the most ideal form of a device for rehabilitation. This introduces a second class of devices beyond passive orthotics. It is comprised of "active" or powered devices, and although more complicated in design, they are definitely the most versatile. An active or powered orthotic, usually employs some type of actuator(s. Methods In this paper we present several new advancements in the area of smart rehabilitation devices that have been developed by the Northeastern University Robotics and Mechatronics Laboratory. They are all compact, wearable and portable devices and boast re-programmable, real time computer controlled functions as the central theme behind their operation. The sensory information and computer control of the three described devices make for highly efficient and versatile systems that represent a whole new breed in wearable rehabilitation devices. Their applications range from active-assistive rehabilitation to resistance exercise and even have applications in gait training. The three devices described are: a transportable continuous passive motion elbow device, a wearable electro-rheological fluid based knee resistance device, and a wearable electrical stimulation and biofeedback knee device. Results Laboratory tests of the devices

Smart portable rehabilitation devices.

Science.gov (United States)

Mavroidis, Constantinos; Nikitczuk, Jason; Weinberg, Brian; Danaher, Gil; Jensen, Katherine; Pelletier, Philip; Prugnarola, Jennifer; Stuart, Ryan; Arango, Roberto; Leahey, Matt; Pavone, Robert; Provo, Andrew; Yasevac, Dan

2005-07-12

The majority of current portable orthotic devices and rehabilitative braces provide stability, apply precise pressure, or help maintain alignment of the joints with out the capability for real time monitoring of the patient's motions and forces and without the ability for real time adjustments of the applied forces and motions. Improved technology has allowed for advancements where these devices can be designed to apply a form of tension to resist motion of the joint. These devices induce quicker recovery and are more effective at restoring proper biomechanics and improving muscle function. However, their shortcoming is in their inability to be adjusted in real-time, which is the most ideal form of a device for rehabilitation. This introduces a second class of devices beyond passive orthotics. It is comprised of "active" or powered devices, and although more complicated in design, they are definitely the most versatile. An active or powered orthotic, usually employs some type of actuator(s). In this paper we present several new advancements in the area of smart rehabilitation devices that have been developed by the Northeastern University Robotics and Mechatronics Laboratory. They are all compact, wearable and portable devices and boast re-programmable, real time computer controlled functions as the central theme behind their operation. The sensory information and computer control of the three described devices make for highly efficient and versatile systems that represent a whole new breed in wearable rehabilitation devices. Their applications range from active-assistive rehabilitation to resistance exercise and even have applications in gait training. The three devices described are: a transportable continuous passive motion elbow device, a wearable electro-rheological fluid based knee resistance device, and a wearable electrical stimulation and biofeedback knee device. Laboratory tests of the devices demonstrated that they were able to meet their design

Idaho Chemical Processing Plant Process Efficiency improvements

International Nuclear Information System (INIS)

Griebenow, B.

1996-03-01

In response to decreasing funding levels available to support activities at the Idaho Chemical Processing Plant (ICPP) and a desire to be cost competitive, the Department of Energy Idaho Operations Office (DOE-ID) and Lockheed Idaho Technologies Company have increased their emphasis on cost-saving measures. The ICPP Effectiveness Improvement Initiative involves many activities to improve cost effectiveness and competitiveness. This report documents the methodology and results of one of those cost cutting measures, the Process Efficiency Improvement Activity. The Process Efficiency Improvement Activity performed a systematic review of major work processes at the ICPP to increase productivity and to identify nonvalue-added requirements. A two-phase approach was selected for the activity to allow for near-term implementation of relatively easy process modifications in the first phase while obtaining long-term continuous improvement in the second phase and beyond. Phase I of the initiative included a concentrated review of processes that had a high potential for cost savings with the intent of realizing savings in Fiscal Year 1996 (FY-96.) Phase II consists of implementing long-term strategies too complex for Phase I implementation and evaluation of processes not targeted for Phase I review. The Phase II effort is targeted for realizing cost savings in FY-97 and beyond

Costs and benefits of energy efficiency improvements in ceiling fans

Energy Technology Data Exchange (ETDEWEB)

Shah, Nihar; Sathaye, Nakul; Phadke, Amol; Letschert, Virginie [Lawrence Berkeley National Lab., CA (United States). Environmental Energy Technology Division

2013-10-15

Ceiling fans contribute significantly to residential electricity consumption, especially in developing countries with warm climates. The paper provides analysis of costs and benefits of several options to improve the efficiency of ceiling fans to assess the global potential for electricity savings and green house gas (GHG) emission reductions. Ceiling fan efficiency can be cost-effectively improved by at least 50% using commercially available technology. If these efficiency improvements are implemented in all ceiling fans sold by 2020, 70 terawatt hours per year could be saved and 25 million metric tons of carbon dioxide equivalent (CO2-e) emissions per year could be avoided, globally. We assess how policies and programs such as standards, labels, and financial incentives can be used to accelerate the adoption of efficient ceiling fans in order to realize potential savings.

Light-Emitting Devices Based on Pyridine-Containing Conjugated Polymers

National Research Council Canada - National Science Library

Wang, Y

1997-01-01

...) as hole transporting/electron blocking polymer, which improves the device efficiency and brightness significantly due to the charge confinement and exciplex emission at the PVK/emitting polymer interface...

Research to Improve the Efficiency of Double Stereo PCR Microfluidic Chip by Passivating the Inner Surface of Steel Capillary with NOA61.

Science.gov (United States)

Wu, Jian; Guo, Wei; Wang, Chunyan; Yu, Kuanxin; Ma, Ying; Chen, Tao; Li, Yinghui

2015-06-01

In this paper, we report the improvement of PCR microfluidic chip efficiency achieved by coating the inner surface of steel capillary microchannel with a 22-µm film of the ultraviolet-solidified NOA61 using a device invented by us. Our results indicate that with this treatment, the roughness of the inside wall of steel capillary was improved from Ra = 0.921 to Ra = 0.254. The contact angle was decreased from about 95° to 56°, and the surface hydrophobicity was also increased. The flow pressure for performing the real-time PCR in the microfluidic chip with modified surface was reduced by twofold (2.11/1) and that resulted in a substantially increased efficiency of PCR. A modification of the microchannel interior surface improved the quality of the on-chip integrated PCR procedure.

Cermet insert high voltage holdoff improvement for ceramic/metal vacuum devices

Science.gov (United States)

Ierna, W.F.

1986-03-11

An improved metal-to-ceramic seal is provided wherein the ceramic body of the seal contains an integral region of cermet material in electrical contact with the metallic member, e.g., an electrode, of the seal. The seal is useful in high voltage vacuum devices, e.g., vacuum switches, and increases the high-voltage holdoff capabilities of such devices. A method of fabricating such seals is also provided.

Modeling of detective quantum efficiency considering scatter-reduction devices

Energy Technology Data Exchange (ETDEWEB)

Park, Ji Woong; Kim, Dong Woon; Kim, Ho Kyung [Pusan National University, Busan (Korea, Republic of)

2016-05-15

The reduction of signal-to-noise ratio (SNR) cannot be restored and thus has become a severe issue in digital mammography.1 Therefore, antiscatter grids are typically used in mammography. Scatter-cleanup performance of various scatter-reduction devices, such as air gaps,2 linear (1D) or cellular (2D) grids,3, 4 and slot-scanning devices,5 has been extensively investigated by many research groups. In the present time, a digital mammography system with the slotscanning geometry is also commercially available.6 In this study, we theoretically investigate the effect of scattered photons on the detective quantum efficiency (DQE) performance of digital mammography detectors by using the cascaded-systems analysis (CSA) approach. We show a simple DQE formalism describing digital mammography detector systems equipped with scatter reduction devices by regarding the scattered photons as additive noise sources. The LFD increased with increasing PMMA thickness, and the amounts of LFD indicated the corresponding SF. The estimated SFs were 0.13, 0.21, and 0.29 for PMMA thicknesses of 10, 20, and 30 mm, respectively. While the solid line describing the measured MTF for PMMA with 0 mm was the result of least-squares of regression fit using Eq. (14), the other lines were simply resulted from the multiplication of the fit result (for PMMA with 0 mm) with the (1-SF) estimated from the LFDs in the measured MTFs. Spectral noise-power densities over the entire frequency range were not much changed with increasing scatter. On the other hand, the calculation results showed that the spectral noise-power densities increased with increasing scatter. This discrepancy may be explained by that the model developed in this study does not account for the changes in x-ray interaction parameters for varying spectral shapes due to beam hardening with increasing PMMA thicknesses.

New raw materials improve packing sealing efficiency

International Nuclear Information System (INIS)

Igel, B.; McKeague, L.

2012-01-01

End-users and OEM's using or manufacturing on/off and control valves expect a permanent and effective increase in service life together with an increased sealing capability while at the same time minimizing maintenance concerns. Developing materials which provide consistency and repeatability are essential characteristics to optimizing valve performance. “New Generation” materials and yarn allow us to meet this growing demand while complying with the requirements related to chemical purity and an increased level of safety to both plant workers and equipment in the nuclear environment. Through R&D initiatives and developments in new and improved raw materials; a new mechanical packing generation which optimizes friction coefficients and extended life cycle has been introduced to the industry. Lower friction values drastically optimize actuator effort and size improving efficiency for stem operation with significant improvements in flow control of fluids. Combined with new and improved procedures (installation, torque levels and consolidation recommendations), this new packing generation has provided significant improvement in the mechanical behavior of packing materials (independent tests carried out in collaboration with AECL and CETIM) this has provided the opportunity to develop successful Valve Enhancement Programs which offer improved efficiency, valve operation and repeatability. These NEW generation yarns are available with or without wire reinforcement depending on specific operating parameters and conditions. The purpose of this presentation is to demonstrate that new generation material(s). Which are available to the industry for AOV, MOV and Manual valves? - To highlight the steps taken in R&D and manufacturing contributing to the much improved yarns and finished packing products. - Comply and are designed to meet the stringent requirements in the nuclear industry - Simplify valve maintenance without risk to safety or performance - Increase service

Use of Physics Innovative Device for Improving Students‟ Motivation and Performance in Learning Selected Concepts in Physics

Directory of Open Access Journals (Sweden)

Virginia Songalia Sobremisana

2017-11-01

Full Text Available This research was focused on the development and evaluation of physics innovative device in enhancing students’ motivation and performance in learning selected concepts in physics. The Physics innovative device was developed based upon research on student difficulties in learning relevant concepts in physics and their attitudes toward the subject. Basic concepts in mechanics were also made as baselines in the development of the locally-produced Physics innovative learning device. Such learning devices are valuable resources when used either in lecture or demonstration classes. The developmental, descriptive and quasi-experimental research methods were utilized to determine the effectiveness, in terms of motivation and performance, of the innovative device in Physics. The instruments used for the data collection were the Instructional Materials Motivational Scale (IMMS developed by Keller and the students’ performance test. Pretest and posttest mean scores were measured to determine if there is a mean gain score difference between the experimental and control groups. The study revealed that the group taught with the Physics innovative device performed significantly better than those taught in the traditional method and also the use of Physics innovative device generally improved students’ understanding of concepts and led to higher academic achievements. Analysis of the students’ level of motivation showed that their interests were captured, the instructions they received were relevant to their personal goals and motives, their confidence to learn on their own were build-up, and learning for them was rewarding and important. In the four dimensions (ARCS of IMMS students were found to be attentive, confident, and in agreement in using the fun-learning tool having realize its applicability and relevance in learning their Physics lessons. Results of the study disclosed students and teachers consider the novel device acceptable because it is

Hybrid Back Surface Reflector GaInAsSb Thermophotovoltaic Devices

International Nuclear Information System (INIS)

RK Huang; CA Wang; MK Connors; GW Turner; M Dashiell

2004-01-01

Back surface reflectors have the potential to improve thermophotovoltaic (TPV) device performance though the recirculation of infrared photons. The ''hybrid'' back-surface reflector (BSR) TPV cell approach allows one to construct BSRs for TPV devices using conventional, high efficiency, GaInAsSb-based TPV material. The design, fabrication, and measurements of hybrid BSR-TPV cells are described. The BSR was shown to provide a 4 mV improvement in open-circuit voltage under a constant shortcircuit current, which is comparable to the 5 mV improvement theoretically predicted. Larger improvements in open-circuit voltage are expected in the future with materials improvements

Efficiency improvements in transport

Energy Technology Data Exchange (ETDEWEB)

Schramm, J. [Technical Univ. of Denmark. DTU Mechanical Engineering, Kgs. Lyngby (Denmark); Christensen, Linda; Jensen, Thomas C. [Technical Univ. of Denmark. DTU Transport, Kgs. Lyngby (Denmark)

2012-11-15

Transport of people, personal belongings and goods in private cars is fundamental to our modern welfare society and economic growth, and has grown steadily over many decades. Motor fuels have been based almost entirely on crude oil for the last century. During the last couple of decades engines built for traditional fuels have become more advanced and efficient; this has reduced fuel consumption by around 40% and emissions by more than 90%. Only in the same time span have we begun to look at alternatives to fossil fuels. Biofuels such as biodiesel, bioethanol, biomethanol and biogas can replace petrol and diesel, and in recent years algae have shown a new potential for diesel fuel. Natural gas is also becoming an interesting fuel due to its large resources worldwide. GTL, CTL and BTL are liquid fuels produced from solid or gaseous sources. GTL and CTL are expensive to produce and not very CO{sub 2}-friendly, but they are easily introduced and need little investment in infrastructure and vehicles. DME is an excellent fuel for diesel engines. Methanol and DME produced from biomass are among the most CO{sub 2}-reducing fuels and at the same time the most energy-efficient renewable fuels. Fuel cell vehicles (FCVs) are currently fuelled by hydrogen, but other fuels are also possible. There are, however, several barriers to the implementation of fuel cell vehicles. In particular, a hydrogen infrastructure needs to be developed. Electric vehicles (EVs) have the advantage that energy conversion is centralised at the power plant where it can be done at optimum efficiency and emissions. EVs have to be charged at home, and also away from home when travelling longer distances. With an acceptable fast charging infrastructure at least 85% of the one-car families in Denmark could be potential EV customers. Range improvements resulting from better batteries are expected to create a large increase in the number of EVs in Denmark between 2020 and 2030. The hybrid electric vehicle

Upgrading and efficiency improvement in coal-fired power plants

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-08-01

Improving the efficiencies of the large number of older coal-fired power plants operating around the world would give major savings in CO2 emissions together with significant other benefits. This report begins with a summary of the ways efficiency can become degraded and of the means available to combat the decrease in performance. These include improvements to operating and maintenance practices and more major techniques that are available, including boiler and turbine retrofits. There is also an update on fuel drying developments as a route to higher efficiency in plants firing high moisture lignites. The largest chapter of the report contains a number of descriptions of case study improvement projects, to illustrate measures that have been applied, benefits that have been achieved and identify best practices, which are summarised. Major national and international upgrading programmes are described.

Radiographic film digitizing devices

International Nuclear Information System (INIS)

McFee, W.H.

1988-01-01

Until recently, all film digitizing devices for use with teleradiology or picture archiving and communication systems used a video camera to capture an image of the radiograph for subsequent digitization. The development of film digitizers that use a laser beam to scan the film represents a significant advancement in digital technology, resulting in improved image quality compared with video scanners. This paper discusses differences in resolution, efficiency, reliability, and the cost between these two types of devices. The results of a modified receiver operating characteristic comparison study of a video scanner and a laser scanner manufactured by the same company are also discussed

Improvement of the Dehulling Efficiency of Sorghum and Millet using ...

African Journals Online (AJOL)

Conditioning of grain with heat and moisture is known to loosen the adhesion of the seed coat from the endosperm and therefore improve the dehulling efficiency of some grains such as beans, cowpea and canola. This study investigated the effect of hydrothermal treatment on the improvement of dehulling efficiency of ...

Ruthenium separation device from radioactive waste

International Nuclear Information System (INIS)

Ayabe, Osao.

1988-01-01

Purpose: To efficiently oxidize ruthenium in radioactive wastes and evaporize ruthenium tetraoxide after oxidization thereof, thereby improve the separation and recovery rate. Constitution: The device comprises an oxidization vessel for supplying an oxidizing agent into radioactive wastes to oxidize ruthenium in the wastes into ruthenium tetraoxide, and a distillation vessel for introducing radioactive wastes after oxidization, distillating under heating ruthenium tetraoxide leached into the wastes and evaporizing ruthenium tetraoxide. By dividing the device into the oxidizing vessel and the distillation vessel, the oxidizing treatment and the distilling treatment can individually be operated optimally to improve the separation and recovery rate of ruthenium. (Takahashi, M.)

Utility of a simple lighting device to improve chest compressions learning.

Science.gov (United States)

González-Calvete, L; Barcala-Furelos, R; Moure-González, J D; Abelairas-Gómez, C; Rodríguez-Núñez, A

2017-11-01

The recommendations on cardiopulmonary resuscitation (CPR) emphasize the quality of the manoeuvres, especially chest compressions (CC). Audiovisual feedback devices could improve the quality of the CC during CPR. The aim of this study was to evaluate the usefulness of a simple lighting device as a visual aid during CPR on a mannequin. Twenty-two paediatricians who attended an accredited paediatric CPR course performed, in random order, 2min of CPR on a mannequin without and with the help of a simple lighting device, which flashes at a frequency of 100 cycles per minute. The following CC variables were analyzed using a validated compression quality meter (CPRmeter ® ): depth, decompression, rate, CPR time and percentage of compressions. With the lighting device, participants increased average quality (60.23±54.50 vs. 79.24±9.80%; P=.005), percentage in target depth (48.86±42.67 vs. 72.95±20.25%; P=.036) and rate (35.82±37.54 vs. 67.09±31.95%; P=.024). A simple light device that flashes at the recommended frequency improves the quality of CC performed by paediatric residents on a mannequin. The usefulness of this CPR aid system should be assessed in real patients. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Fuel inspection device

International Nuclear Information System (INIS)

Tsuji, Tadashi.

1990-01-01

The fuel inspection device of the present invention has a feature of obtaining an optimum illumination upon fuel rod interval inspection operation in a fuel pool. That is, an illumination main body used underwater is connected to a cable which is led out on a floor. A light control device is attached to the other end of the cable and an electric power cable is connected to the light control device. A light source (for example, incandescent lamp) is incorporated in the casing of the illumination main body, and a diffusion plate is disposed at the front to provide a plane light source. The light control device has a light control knob capable of remote-controlling the brightness of the light of the illumination main body. In the fuel inspection device thus constituted, halation is scarcely caused on the image screen upon inspection of fuels by a submerged type television camera to facilitate control upon inspection. Accordingly, efficiency of the fuel inspection can be improved to shorten the operation time. (I.S.)

ENERGY EFFICIENT DESALINATOR

Directory of Open Access Journals (Sweden)

T. A. Ismailov

2017-01-01

Full Text Available Objectives. The aim of the research is to develop a thin-film semiconductor thermoelectric heat pump of cylindrical shape for the desalination of sea water.Methods. To improve the efficiency of the desalination device, a  special thin-film semiconductor thermoelectric heat pump of  cylindrical shape is developed. The construction of the thin-film  semiconductor thermoelectric heat pump allows the flow rates of  incoming sea water and outflowing fresh water and brine to be  equalised by changing the geometric dimensions of the desalinator.  The cross-sectional area of the pipeline for incoming sea water is equal to the total area of outflowing fresh water and brine.Results. The use of thin-film semiconductor p- and n-type branches  in a thermo-module reduces their electrical resistance virtually to  zero and completely eliminates Joule's parasitic heat release. The  Peltier thermoelectric effect on heating and cooling is completely  preserved, bringing the efficiency of the heat pump to almost 100%, improving the energy-saving characteristics of the  desalinator as a whole. To further increase the efficiency of the  proposed desalinator, thermoelectric modules with radiation can be  used as thermoelectric devices.Conclusion. As a consequence of the creation of conditions of high rarefaction under which water will be converted to steam, which, at  20° C, is cold (as is the condensed distilled water, energy costs can  be reduced. In this case, the energy for heating and cooling is not  wasted; moreover, sterilisation is also achieved using the ultraviolet  radiation used in the thermoelectric devices, which, on the one hand, generate electromagnetic ultraviolet radiation, and, on the other, cooling. Such devices operate in optimal mode without heat  release. The desalination device can be used to produce fresh water and concentrated solutions from any aqueous solutions, including wastewater from industrial

Mechanistic evaluation of the pros and cons of digital RT-LAMP for HIV-1 viral load quantification on a microfluidic device and improved efficiency via a two-step digital protocol.

Science.gov (United States)

Sun, Bing; Shen, Feng; McCalla, Stephanie E; Kreutz, Jason E; Karymov, Mikhail A; Ismagilov, Rustem F

2013-02-05

validation is essential before a method is considered to provide absolute quantification; (ii) the sensitivity of dLAMP to the sequence of the target nucleic acid necessitates additional validation with patient samples carrying the full spectrum of mutations; (iii) for multistep digital amplification chemistries, such as a combination of reverse transcription with amplification, microfluidic devices may be used to decouple these steps from one another and to perform them under different, individually optimized conditions for improved efficiency.

Energy-Efficient Real-Time Human Activity Recognition on Smart Mobile Devices

Directory of Open Access Journals (Sweden)

Jin Lee

2016-01-01

Full Text Available Nowadays, human activity recognition (HAR plays an important role in wellness-care and context-aware systems. Human activities can be recognized in real-time by using sensory data collected from various sensors built in smart mobile devices. Recent studies have focused on HAR that is solely based on triaxial accelerometers, which is the most energy-efficient approach. However, such HAR approaches are still energy-inefficient because the accelerometer is required to run without stopping so that the physical activity of a user can be recognized in real-time. In this paper, we propose a novel approach for HAR process that controls the activity recognition duration for energy-efficient HAR. We investigated the impact of varying the acceleration-sampling frequency and window size for HAR by using the variable activity recognition duration (VARD strategy. We implemented our approach by using an Android platform and evaluated its performance in terms of energy efficiency and accuracy. The experimental results showed that our approach reduced energy consumption by a minimum of about 44.23% and maximum of about 78.85% compared to conventional HAR without sacrificing accuracy.

Low Mass Printable Devices for Energy Capture, Storage, and Use

Science.gov (United States)

Frazier, Donald O.; Singer, Christopher E.; Rogers, Jan R.; Schramm, Harry F.; Fabisinski, Leo L.; Lowenthal, Mark; Ray, William J.; Fuller, Kirk A.

2010-01-01

The energy-efficient, environmentally friendly technology that will be presented is the result of a Space Act Agreement between NthDegree Technologies Worldwide, Inc., and the National Aeronautics and Space Administration's (NASA's) Marshall Space Flight Center (MSFC). The work combines semiconductor and printing technologies to advance lightweight electronic and photonic devices having excellent potential for commercial and exploration applications. Device development involves three projects that relate to energy generation and consumption: (1) a low-mass efficient (low power, low heat emission) micro light-emitting diode (LED) area lighting device; (2) a low-mass omni-directional efficient photovoltaic (PV) device with significantly improved energy capture; and (3) a new approach to building super-capacitors. These three technologies, energy capture, storage, and usage (e.g., lighting), represent a systematic approach for building efficient local micro-grids that are commercially feasible; furthermore, these same technologies, appropriately replacing lighting with lightweight power generation, will be useful for enabling inner planetary missions using smaller launch vehicles and to facilitate surface operations during lunar and planetary surface missions. The PV device model is a two sphere, light trapped sheet approximately 2-mm thick. The model suggests a significant improvement over current thin film systems. For lighting applications, all three technology components are printable in-line by printing sequential layers on a standard screen or flexographic direct impact press using the three-dimensional printing technique (3DFM) patented by NthDegree. One primary contribution to this work in the near term by the MSFC is to test the robustness of prototype devices in the harsh environments that prevail in space and on the lunar surface. It is anticipated that this composite device, of which the lighting component has passed off-gassing testing, will function

Probabilistic analysis of the efficiency of the damping devices against nuclear fuel container falling

Science.gov (United States)

Králik, Juraj

2017-07-01

The paper presents the probabilistic and sensitivity analysis of the efficiency of the damping devices cover of nuclear power plant under impact of the container of nuclear fuel of type TK C30 drop. The finite element idealization of nuclear power plant structure is used in space. The steel pipe damper system is proposed for dissipation of the kinetic energy of the container free fall. The experimental results of the shock-damper basic element behavior under impact loads are presented. The Newmark integration method is used for solution of the dynamic equations. The sensitivity and probabilistic analysis of damping devices was realized in the AntHILL and ANSYS software.

Reducing the efficiency–stability–cost gap of organic photovoltaics with highly efficient and stable small molecule acceptor ternary solar cells

KAUST Repository

Baran, Derya

2016-11-21

Technological deployment of organic photovoltaic modules requires improvements in device light-conversion efficiency and stability while keeping material costs low. Here we demonstrate highly efficient and stable solar cells using a ternary approach, wherein two non-fullerene acceptors are combined with both a scalable and affordable donor polymer, poly(3-hexylthiophene) (P3HT), and a high-efficiency, low-bandgap polymer in a single-layer bulk-heterojunction device. The addition of a strongly absorbing small molecule acceptor into a P3HT-based non-fullerene blend increases the device efficiency up to 7.7 ± 0.1% without any solvent additives. The improvement is assigned to changes in microstructure that reduce charge recombination and increase the photovoltage, and to improved light harvesting across the visible region. The stability of P3HT-based devices in ambient conditions is also significantly improved relative to polymer:fullerene devices. Combined with a low-bandgap donor polymer (PBDTTT-EFT, also known as PCE10), the two mixed acceptors also lead to solar cells with 11.0 ± 0.4% efficiency and a high open-circuit voltage of 1.03 ± 0.01 V.

Reducing the efficiency–stability–cost gap of organic photovoltaics with highly efficient and stable small molecule acceptor ternary solar cells

KAUST Repository

Baran, Derya; Ashraf, Raja; Hanifi, David A.; Abdelsamie, Maged; Gasparini, Nicola; Rö hr, Jason A.; Holliday, Sarah; Wadsworth, Andrew; Lockett, Sarah; Neophytou, Marios; Emmott, Christopher J. M.; Nelson, Jenny; Brabec, Christoph J.; Amassian, Aram; Salleo, Alberto; Kirchartz, Thomas; Durrant, James R.; McCulloch, Iain

2016-01-01

Technological deployment of organic photovoltaic modules requires improvements in device light-conversion efficiency and stability while keeping material costs low. Here we demonstrate highly efficient and stable solar cells using a ternary approach, wherein two non-fullerene acceptors are combined with both a scalable and affordable donor polymer, poly(3-hexylthiophene) (P3HT), and a high-efficiency, low-bandgap polymer in a single-layer bulk-heterojunction device. The addition of a strongly absorbing small molecule acceptor into a P3HT-based non-fullerene blend increases the device efficiency up to 7.7 ± 0.1% without any solvent additives. The improvement is assigned to changes in microstructure that reduce charge recombination and increase the photovoltage, and to improved light harvesting across the visible region. The stability of P3HT-based devices in ambient conditions is also significantly improved relative to polymer:fullerene devices. Combined with a low-bandgap donor polymer (PBDTTT-EFT, also known as PCE10), the two mixed acceptors also lead to solar cells with 11.0 ± 0.4% efficiency and a high open-circuit voltage of 1.03 ± 0.01 V.

Improving actuation efficiency through variable recruitment hydraulic McKibben muscles: modeling, orderly recruitment control, and experiments.

Science.gov (United States)

Meller, Michael; Chipka, Jordan; Volkov, Alexander; Bryant, Matthew; Garcia, Ephrahim

2016-11-03

Hydraulic control systems have become increasingly popular as the means of actuation for human-scale legged robots and assistive devices. One of the biggest limitations to these systems is their run time untethered from a power source. One way to increase endurance is by improving actuation efficiency. We investigate reducing servovalve throttling losses by using a selective recruitment artificial muscle bundle comprised of three motor units. Each motor unit is made up of a pair of hydraulic McKibben muscles connected to one servovalve. The pressure and recruitment state of the artificial muscle bundle can be adjusted to match the load in an efficient manner, much like the firing rate and total number of recruited motor units is adjusted in skeletal muscle. A volume-based effective initial braid angle is used in the model of each recruitment level. This semi-empirical model is utilized to predict the efficiency gains of the proposed variable recruitment actuation scheme versus a throttling-only approach. A real-time orderly recruitment controller with pressure-based thresholds is developed. This controller is used to experimentally validate the model-predicted efficiency gains of recruitment on a robot arm. The results show that utilizing variable recruitment allows for much higher efficiencies over a broader operating envelope.

Improvement of cosmic ray ruggedness of hybrid vehicles power semiconductor devices

International Nuclear Information System (INIS)

Nishida, Shuichi; Ohnishi, Toyokazu; Fujikawa, Touma; Nose, Noboru; Hamada, Kimimori; Shoji, Tomoyuki; Ishiko, Masayasu

2010-01-01

Power semiconductors which are used under high voltage conditions in HVs (Hybrid Vehicles) are required to have high destruction tolerance against cosmic rays as well as to meet conventional quality standards. In this paper, an SEB (Single Event Burnout) failure mechanism induced by cosmic rays in IGBTs (Insulated Gate Bipolar Transistors) was investigated. Through an optimized device design in which thyristor action was suppressed, the device destruction tolerance was greatly improved. (author)

FACTS device control strategy using PMU

Directory of Open Access Journals (Sweden)

Mohd Tauseef Khan

2016-09-01

Full Text Available The laying and commissioning of new transmission line is very difficult due to socio-economic problems, like environmental clearances, right of way, etc. Therefore, there is an emphasis on better utilization of available transmission infrastructure. FACTS devices can provide reactive power compensation, transmission capability enhancement, and voltage and stability improvement. FACTS devices operate under the command of system operator who analyses its demand by the data acquired through traditional SCADA system, state estimation algorithms and PMUs. SCADA together with PMU give accurate information about the operational state of power system. This paper proposes a scheme to automate the FACTS devices in collaboration with PMUs in a more efficient way. Highly precised data from PMUs can be fed to intelligent controllers for effective analyzing and automating the FACTS device through control command. Thus, this combination can provide real time control of reactive power, together with enhancement of power handling capability and stability improvement.

Does automation improve stock market efficiency in Ghana ...

African Journals Online (AJOL)

The automation of the Ghana Stock Exchange (GSE) in 2008, among other reforms, was expected to improve the efficiency of the market. The extent of this truism has, however, not been empirically established for the GSE. In this study, we attempt to assess the impact of the automation on the efficiency of the GSE within the ...

Integrated hospital emergency care improves efficiency.

Science.gov (United States)

Boyle, A A; Robinson, S M; Whitwell, D; Myers, S; Bennett, T J H; Hall, N; Haydock, S; Fritz, Z; Atkinson, P

2008-02-01

There is uncertainty about the most efficient model of emergency care. An attempt has been made to improve the process of emergency care in one hospital by developing an integrated model. The medical admissions unit was relocated into the existing emergency department and came under the 4-hour target. Medical case records were redesigned to provide a common assessment document for all patients presenting as an emergency. Medical, surgical and paediatric short-stay wards were opened next to the emergency department. A clinical decision unit replaced the more traditional observation unit. The process of patient assessment was streamlined so that a patient requiring admission was fully clerked by the first attending doctor to a level suitable for registrar or consultant review. Patients were allocated directly to specialty on arrival. The effectiveness of this approach was measured with routine data over the same 3-month periods in 2005 and 2006. There was a 16.3% decrease in emergency medical admissions and a 3.9% decrease in emergency surgical admissions. The median length of stay for emergency medical patients was reduced from 7 to 5 days. The efficiency of the elective surgical services was also improved. Performance against the 4-hour target declined but was still acceptable. The number of bed days for admitted surgical and medical cases rose slightly. There was an increase in the number of medical outliers on surgical wards, a reduction in the number of incident forms and formal complaints and a reduction in income for the hospital. Integrated emergency care has the ability to use spare capacity within emergency care. It offers significant advantages beyond the emergency department. However, improved efficiency in processing emergency patients placed the hospital at a financial disadvantage.

Dye-sensitized solar cell module realized photovoltaic and photothermal highly efficient conversion via three-dimensional printing technology

Institute of Scientific and Technical Information of China (English)

Qi-Zhang Huang; Yan-Qing Zhu; Ji-Fu Shi; Lei-Lei Wang; Liu-Wen Zhong; Gang Xu

2017-01-01

Three-dimensional (3D) printing technology is employed to improve the photovoltaic and photothermal conversion efficiency of dye-sensitized solar cell (DSC) module.The 3D-printed concentrator is optically designed and improves the photovoltaic efficiency of the DSC module from 5.48％ to 7.03％.Additionally,with the 3D-printed microfluidic device serving as water cooling,the temperature of the DSC can be effectively controlled,which is beneficial for keeping a high photovoltaic conversion efficiency for DSC module.Moreover,the 3D-printed microfluidic device can realize photothermal conversion with an instantaneous photothermal efficiency of 42.1％.The integrated device realizes a total photovoltaic and photothermal conversion efficiency of 49％ at the optimal working condition.

Functionalized carbon nanotube doping of P3HT:PCBM photovoltaic devices for enhancing short circuit current and efficiency

Directory of Open Access Journals (Sweden)

Rohit Bhatia

2017-03-01

Full Text Available We have successfully functionalized multiwalled carbon nanotubes (MWCNTs using nitrene approach employing the two aryl azides as a precursor for nitrene generation. The dispersion of functionalized MWCNTs has been enhanced in various organic solvents. These functionalized MWCNTs have been successfully doped in various concentrations in the bulk heterojunction (BHJ organic photovoltaic (OPV cells with a poly (3-hexyl thiophene (P3HT and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM photoactive blended layer. The incorporation of MWCNTs with aryl functional groups, in active the layer, results in enhanced performance with respect to a reference cell. The maximum power conversion efficiency of 1.86% is achieved with adduct I while in the case of adduct II it gets double to 2.0% in comparison with a reference cell. This improvement in the device performance is attributed to enhanced exciton dissociation and improved charge transport properties due to the formation of a nanotube percolation network in the photoactive composite layer.

Non-fullerene electron acceptors for organic photovoltaic devices

Energy Technology Data Exchange (ETDEWEB)

Jenekhe, Samson A.; Li, Haiyan; Earmme, Taeshik; Ren, Guoqiang

2017-11-07

Non-fullerene electron acceptors for highly efficient organic photovoltaic devices are described. The non-fullerene electron acceptors have an extended, rigid, .pi.-conjugated electron-deficient framework that can facilitate exciton and charge derealization. The non-fullerene electron acceptors can physically mix with a donor polymer and facilitate improved electron transport. The non-fullerene electron acceptors can be incorporated into organic electronic devices, such as photovoltaic cells.

Improving the efficiency and environmental stability of inverted planar perovskite solar cells via silver-doped nickel oxide hole-transporting layer

Science.gov (United States)

Wei, Ying; Yao, Kai; Wang, Xiaofeng; Jiang, Yihua; Liu, Xueyuan; Zhou, Naigen; Li, Fan

2018-01-01

In this paper, we demonstrate the high-performance inverted planar heterojunction perovskite solar cells (PeSCs) based on the novel inorganic hole-transporting layer (HTL) of silver (Ag)-doped NiOx (Ag:NiOx). Density-functional theory (DFT) calculation reveals that Ag prefers to occupy the substitutional Ni site (AgNi) and behaves as an acceptor in NiO lattice. Compared with the pristine NiOx films, appropriate Ag doping can increase the optical transparency, work function, electrical conductivity and hole mobility of NiOx films. Moreover, the CH3NH3PbI3 perovskite films grown on Ag:NiOx exhibit better crystallinity, higher coverage and smoother surface with densely packed larger grains than those grown on the pristine NiOx film. Consequently, the Ag:NiOx HTL boosts the efficiency of the inverted planar heterojunction PeSCs from 13.46% (for the pristine NiOx-based device) to 16.86% (for the 2 at.% Ag:NiOx-based device). Furthermore, the environmental stability of PeSCs based on Ag:NiOx HTL is dramatically improved compared to devices based on organic HTLs and pristine NiOx HTLs. This work provides a simple and effective HTL material system for high-efficient and stable PeSCs.

Particle supply and recovery device

International Nuclear Information System (INIS)

Yamada, Kimio; Okazaki, Takashi.

1988-01-01

This invention concerns a particle supply and recovery device suitable to the supply of fuels and exhaustion of reaction products in a tokamak device. The divertor chamber is divided into an inner side and an outer side, in which only the outer side is constituted as a tightly closed structure. Particles are supplied from the inside of main plasmas and exhausted from the outer side of the divertor chamber. In the divertor equilibrium arrangement, particles escaping from the main plasmas are conveyed mainly passing through the outer side scrape-off layer to the divertor chamber. The particle density is higher at the outer side and lower at the inner side of the scrape-off layer. By making the outer side as a tightly closed structure, the pressure is increased and the particle exhaustion efficiency is improved. Since the particle density is low in the inner scrape-layer, the particle supply efficiency to the main plasma is increased by supplying the particles from the inside. Further, particles ionized in the inner scrape-off layer are returned to the main plasma chamber and then supplied again since the inner divertor chamber is not closed. Accordingly, the particle supply efficiency can further be improved. (K.M.)

Improvement in deuterium recovery from water–isotope mixture by thermal diffusion in the device of branch columns

International Nuclear Information System (INIS)

Hsu, Ching-Chun; Yeh, Ho-Ming

2014-01-01

Highlights: • Recovery of deuterium by thermal diffusion from water–isotope mixture has been investigated. • The undesirable remixing effect can be reduced by employing the device of branch columns. • Deuterium recoveries were compared with that in a single column of the same total column length. • Considerable recovery improvement is obtainable in the device of branch columns, instead of in a single-column device. - Abstract: Deuterium recovery from water–isotopes mixture using thermal diffusion can be improved by employing the branch column device, instead of single column devices, with the same total column length. The remixing effect due to convection currents in a thermal diffusion column for heavy water enrichment is thus reduced and separation improvement increases when the flow rate or the total column length increases. The improvement in separation can reach about 50% for the numerical example given

Energy efficiency improvements in ammonia production--perspectives and uncertainties

International Nuclear Information System (INIS)

Rafiqul, Islam; Weber, Christoph; Lehmann, Bianca; Voss, Alfred

2005-01-01

The paper discusses the energy consumption and energy saving potential for a major energy-intensive product in the chemical industry-ammonia, based on technologies currently in use and possible process improvements. The paper consists of four parts. In the first part, mainly references to various ammonia production technologies are given. Energy consumption, emissions and saving potentials are discussed in the second part. Thereby, the situation in Europe, the US and India is highlighted and various data sources are compared. In the third part of the paper, a novel approach for modeling energy efficiency improvements is described that accounts for uncertainties and unobserved heterogeneity in the production processes. Besides new investments, revamping investments are also included in the modeling and the development of the production stock is accounted for. Finally, in the fourth part, this approach is applied to the modeling of energy efficiency improvements and CO 2 emission reductions in ammonia production. Thereby, considerable improvements in specific energy use and CO 2 emissions are found in the reference scenario, yet under the assumption of high oil and gas prices, a partial switch to coal based technologies is expected which lowers notably the CO 2 efficiency. Introduction of a CO 2 penalty under a certificate trading or other regime is on contrary found to foster energy efficiency and the use of low carbon technologies

Light-induced lattice expansion leads to high-efficiency perovskite solar cells

Science.gov (United States)

Tsai, Hsinhan; Asadpour, Reza; Blancon, Jean-Christophe; Stoumpos, Constantinos C.; Durand, Olivier; Strzalka, Joseph W.; Chen, Bo; Verduzco, Rafael; Ajayan, Pulickel M.; Tretiak, Sergei; Even, Jacky; Alam, Muhammad Ashraf; Kanatzidis, Mercouri G.; Nie, Wanyi; Mohite, Aditya D.

2018-04-01

Light-induced structural dynamics plays a vital role in the physical properties, device performance, and stability of hybrid perovskite–based optoelectronic devices. We report that continuous light illumination leads to a uniform lattice expansion in hybrid perovskite thin films, which is critical for obtaining high-efficiency photovoltaic devices. Correlated, in situ structural and device characterizations reveal that light-induced lattice expansion benefits the performances of a mixed-cation pure-halide planar device, boosting the power conversion efficiency from 18.5 to 20.5%. The lattice expansion leads to the relaxation of local lattice strain, which lowers the energetic barriers at the perovskite-contact interfaces, thus improving the open circuit voltage and fill factor. The light-induced lattice expansion did not compromise the stability of these high-efficiency photovoltaic devices under continuous operation at full-spectrum 1-sun (100 milliwatts per square centimeter) illumination for more than 1500 hours.

Color-tunable electrophosphorescent device fabricated by a photo-bleaching method

International Nuclear Information System (INIS)

Kim, Tae-Ho; Park, Jong Hyeok; Park, O Ok

2011-01-01

We demonstrated an efficient color-tunable electrophosphorescent device fabricated by a photo-bleaching method. Electroluminescence studies indicate that excellent device performance can be achieved through efficient Foerster energy transfer from the conjugated polymer to the iridium complexes by improving their miscibility. The use of a very low concentration of red phosphorescent dye and the easy degradation characteristics of conjugated structure of the red dopant enable color-tuning from red to green emission by a simple UV-irradiation process without a sacrifice of luminescent properties.tp

Spreading The Net: The Multiple Benefits Of Energy Efficiency Improvements

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-07-01

Improving energy efficiency can deliver a range of benefits to the economy and society. However energy efficiency programmes are often evaluated only on the basis of the energy savings they deliver. As a result, the full value of energy efficiency improvements in both national and global economies may be significantly underestimated. This also means that energy efficiency policy may not be optimised to target the potential of the full range of outcomes possible. Moreover, when the merit of energy efficiency programmes is judged solely on reductions in energy demand, programmes are susceptible to criticisms related to the rebound effect when the energy savings are less than expected due to other welfare gains. There are several reasons why the full range of outcomes from energy efficiency policy is not generally evaluated. First, it is due to the non-market, somewhat intangible, nature of the socioeconomic benefits, which makes them difficult to quantify. Second, the effects due to energy efficiency alone can be complex to isolate and to determine causality. Third, evaluators and policy makers working in the energy efficiency sphere are usually energy professionals, working for an energy agency or ministry, with little experience of how energy efficiency might impact other non-energy sectors. The result is an under-appreciation – and related underinvestment – in energy efficiency, and as a consequence, missed opportunities and benefits. These foregone benefits represent the ‘opportunity cost’ of failing to adequately evaluate and prioritize energy efficiency investments. The objective of this report is to fully outline the array of different benefits from improved energy efficiency and investigate their implications for policy design. By better understanding the different benefits arising from energy efficiency it should be easier for policy makers to prioritise the most significant outcomes, in addition to energy savings, in optimising energy efficiency

Design of microwave active devices

CERN Document Server

Gautier , Jean-Luc

2014-01-01

This book presents methods for the design of the main microwave active devices. The first chapter focuses on amplifiers working in the linear mode. The authors present the problems surrounding narrowband and wideband impedance matching, stability, polarization and the noise factor, as well as specific topologies such as the distributed amplifier and the differential amplifier. Chapter 2 concerns the power amplifier operation. Specific aspects on efficiency, impedance matching and class of operation are presented, as well as the main methods of linearization and efficiency improvement. Freq

Improving biological efficiency of Oyster mushroom, Pleurotus ...

African Journals Online (AJOL)

International Journal of Biological and Chemical Sciences ... Yield improvement were observed in both pigeon pea and sunflower seed cake supplemented treatments with the highest mycelium vigor (91.65%) and biological ... Keywords: biological efficiency, compost, mycelium vigor, pigeon pea, sunflower seed cake

Earth-Abundant Chalcogenide Photovoltaic Devices with over 5% Efficiency Based on a Cu2 BaSn(S,Se)4 Absorber.

Science.gov (United States)

Shin, Donghyeop; Zhu, Tong; Huang, Xuan; Gunawan, Oki; Blum, Volker; Mitzi, David B

2017-06-01

In recent years, Cu 2 ZnSn(S,Se) 4 (CZTSSe) materials have enabled important progress in associated thin-film photovoltaic (PV) technology, while avoiding scarce and/or toxic metals; however, cationic disorder and associated band tailing fundamentally limit device performance. Cu 2 BaSnS 4 (CBTS) has recently been proposed as a prospective alternative large bandgap (~2 eV), environmentally friendly PV material, with ~2% power conversion efficiency (PCE) already demonstrated in corresponding devices. In this study, a two-step process (i.e., precursor sputter deposition followed by successive sulfurization/selenization) yields high-quality nominally pinhole-free films with large (>1 µm) grains of selenium-incorporated (x = 3) Cu 2 BaSnS 4- x Se x (CBTSSe) for high-efficiency PV devices. By incorporating Se in the sulfide film, absorber layers with 1.55 eV bandgap, ideal for single-junction PV, have been achieved within the CBTSSe trigonal structural family. The abrupt transition in quantum efficiency data for wavelengths above the absorption edge, coupled with a strong sharp photoluminescence feature, confirms the relative absence of band tailing in CBTSSe compared to CZTSSe. For the first time, by combining bandgap tuning with an air-annealing step, a CBTSSe-based PV device with 5.2% PCE (total area 0.425 cm 2 ) is reported, >2.5× better than the previous champion pure sulfide device. These results suggest substantial promise for the emerging Se-rich Cu 2 BaSnS 4- x Se x family for high-efficiency and earth-abundant PV. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

16.1% Efficient Hysteresis-Free Mesostructured Perovskite Solar Cells Based on Synergistically Improved ZnO Nanorod Arrays

KAUST Repository

Mahmood, Khalid

2015-06-01

Significant efficiency improvements are reported in mesoscopic perovskite solar cells based on the development of a low-temperature solution-processed ZnO nanorod (NR) array exhibiting higher NR aspect ratio, enhanced electron density, and substantially reduced work function than conventional ZnO NRs. These features synergistically result in hysteresis-free, scan-independent, and stabilized devices with an efficiency of 16.1%. Electron-rich, nitrogen-doped ZnO (N:ZnO) NR-based electron transporting materials (ETMs) with enhanced electron mobility produced using ammonium acetate show consistently higher efficiencies by one to three power points than undoped ZnO NRs. Additionally, the preferential electrostatic interaction between the -nonpolar facets of N:ZnO and the conjugated polyelectrolyte polyethylenimine (PEI) has been relied on to promote the hydrothermal growth of high aspect ratio NR arrays and substantially improve the infiltration of the perovskite light absorber into the ETM. Using the same interactions, a conformal PEI coating on the electron-rich high aspect ratio N:ZnO NR arrays is -successfully applied, resulting in a favorable work function shift and altogether leading to the significant boost in efficiency from <10% up to >16%. These results largely surpass the state-of-the-art PCE of ZnO-based perovskite solar cells and highlight the benefits of synergistically combining mesoscale control with doping and surface modification. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Empirical LTE Smartphone Power Model with a View to Energy Efficiency Evolution

DEFF Research Database (Denmark)

Lauridsen, Mads; Noël, Laurent; Sørensen, Troels Bundgaard

2014-01-01

measurements made on state-of-the-art LTE smartphones. Discontinuous Reception (DRX) sleep mode is also modeled, because it is one of the most effective methods to improve smartphone battery life. Energy efficiency has generally improved with each Radio Access Technology (RAT) generation, and to see......Smartphone users struggle with short battery life, and this affects their device satisfaction level and usage of the network. To evaluate how chipset manufacturers and mobile network operators can improve the battery life, we propose a Long Term Evolution (LTE) smartphone power model. The idea...... this evolution, we compare the energy efficiency of the latest LTE devices with devices based on Enhanced Data rates for GSM Evolution (EDGE), High Speed Packet Access (HSPA), and Wi-Fi*. With further generations of RAT systems we expect further improvements. To this end, we discuss the new LTE features, Carrier...

Thermally Activated Delayed Fluorescence in Polymers: A New Route toward Highly Efficient Solution Processable OLEDs.

Science.gov (United States)

Nikolaenko, Andrey E; Cass, Michael; Bourcet, Florence; Mohamad, David; Roberts, Matthew

2015-11-25

Efficient intermonomer thermally activated delayed fluorescence is demonstrated for the first time, opening a new route to achieving high-efficiency solution processable polymer light-emitting device materials. External quantum efficiency (EQE) of up to 10% is achieved in a simple fully solution-processed device structure, and routes for further EQE improvement identified. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficiency enhancement in a single emission layer yellow organic light emitting device: Contribution of CIS/ZnS quantum dot

International Nuclear Information System (INIS)

Demir, Nuriye; Oner, Ilker; Varlikli, Canan; Ozsoy, Cihan; Zafer, Ceylan

2015-01-01

Electroluminescence (EL) efficiency from a single emission layer solution processed yellow emitting polymer, i.e. poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,10,3}-thiadiazole)] end-capped with dimethylphenyl (ADS233YE), is firstly enhanced by the optimization of stock polymer concentrations and the coating rates, and then with the addition of copper indium disulfide/zinc sulfide (CIS/ZnS) core/shell quantum dots (QDs). Using these bare core/shell QDs as the active layer in the studied device gave no EL at all. However, yellow EL with the maximum brightness of 56834 cd/m 2 , maximum current efficiency of 4.7 cd/A and maximum power efficiency of 2.3 lm/W is obtained from the device structure of indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/ADS233YE:0.4 wt.% CIS/ZnS QD/Ca/Al those of which correspond to approximately 4 and 2 folds of enhancements in the brightness and luminous and power efficiency values, respectively, compared to that of the device without CIS/ZnS. - Highlights: • Copper indium disulfide/zinc sulfide (CIS/ZnS) particles are synthesized. • Polymer light emitting diode performance of a yellow emitting polymer is enhanced. • The presence of CIS/ZnS in active layer enhanced the power efficiency two folds. • Optimum concentration of CIS/ZnS in polymer is 0.4 wt.%

Efficiency enhancement in a single emission layer yellow organic light emitting device: Contribution of CIS/ZnS quantum dot

Energy Technology Data Exchange (ETDEWEB)

Demir, Nuriye; Oner, Ilker; Varlikli, Canan, E-mail: canan.varlikli@ege.edu.tr; Ozsoy, Cihan; Zafer, Ceylan

2015-08-31

Electroluminescence (EL) efficiency from a single emission layer solution processed yellow emitting polymer, i.e. poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,10,3}-thiadiazole)] end-capped with dimethylphenyl (ADS233YE), is firstly enhanced by the optimization of stock polymer concentrations and the coating rates, and then with the addition of copper indium disulfide/zinc sulfide (CIS/ZnS) core/shell quantum dots (QDs). Using these bare core/shell QDs as the active layer in the studied device gave no EL at all. However, yellow EL with the maximum brightness of 56834 cd/m{sup 2}, maximum current efficiency of 4.7 cd/A and maximum power efficiency of 2.3 lm/W is obtained from the device structure of indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/ADS233YE:0.4 wt.% CIS/ZnS QD/Ca/Al those of which correspond to approximately 4 and 2 folds of enhancements in the brightness and luminous and power efficiency values, respectively, compared to that of the device without CIS/ZnS. - Highlights: • Copper indium disulfide/zinc sulfide (CIS/ZnS) particles are synthesized. • Polymer light emitting diode performance of a yellow emitting polymer is enhanced. • The presence of CIS/ZnS in active layer enhanced the power efficiency two folds. • Optimum concentration of CIS/ZnS in polymer is 0.4 wt.%.

A Process Improvement Evaluation of Sequential Compression Device Compliance and Effects of Provider Intervention.

Science.gov (United States)

Beachler, Jason A; Krueger, Chad A; Johnson, Anthony E

This process improvement study sought to evaluate the compliance in orthopaedic patients with sequential compression devices and to monitor any improvement in compliance following an educational intervention. All non-intensive care unit orthopaedic primary patients were evaluated at random times and their compliance with sequential compression devices was monitored and recorded. Following a 2-week period of data collection, an educational flyer was displayed in every patient's room and nursing staff held an in-service training event focusing on the importance of sequential compression device use in the surgical patient. Patients were then monitored, again at random, and compliance was recorded. With the addition of a simple flyer and a single in-service on the importance of mechanical compression in the surgical patient, a significant improvement in compliance was documented at the authors' institution from 28% to 59% (p < .0001).

Options to improve energy efficiency for educational building

Science.gov (United States)

Jahan, Mafruha

The cost of energy is a major factor that must be considered for educational facility budget planning purpose. The analysis of energy related issues and options can be complex and requires significant time and detailed effort. One way to facilitate the inclusion of energy option planning in facility planning efforts is to utilize a tool that allows for quick appraisal of the facility energy profile. Once such an appraisal is accomplished, it is then possible to rank energy improvement options consistently with other facility needs and requirements. After an energy efficiency option has been determined to have meaningful value in comparison with other facility planning options, it is then possible to utilize the initial appraisal as the basis for an expanded consideration of additional facility and energy use detail using the same analytic system used for the initial appraisal. This thesis has developed a methodology and an associated analytic model to assist in these tasks and thereby improve the energy efficiency of educational facilities. A detailed energy efficiency and analysis tool is described that utilizes specific university building characteristics such as size, architecture, envelop, lighting, occupancy, thermal design which allows reducing the annual energy consumption. Improving the energy efficiency of various aspects of an educational building's energy performance can be complex and can require significant time and experience to make decisions. The approach developed in this thesis initially assesses the energy design for a university building. This initial appraisal is intended to assist administrators in assessing the potential value of energy efficiency options for their particular facility. Subsequently this scoping design can then be extended as another stage of the model by local facility or planning personnel to add more details and engineering aspects to the initial screening model. This approach can assist university planning efforts to

Method for calculating annual energy efficiency improvement of TV sets

International Nuclear Information System (INIS)

Varman, M.; Mahlia, T.M.I.; Masjuki, H.H.

2006-01-01

The popularization of 24 h pay-TV, interactive video games, web-TV, VCD and DVD are poised to have a large impact on overall TV electricity consumption in the Malaysia. Following this increased consumption, energy efficiency standard present a highly effective measure for decreasing electricity consumption in the residential sector. The main problem in setting energy efficiency standard is identifying annual efficiency improvement, due to the lack of time series statistical data available in developing countries. This study attempts to present a method of calculating annual energy efficiency improvement for TV set, which can be used for implementing energy efficiency standard for TV sets in Malaysia and other developing countries. Although the presented result is only an approximation, definitely it is one of the ways of accomplishing energy standard. Furthermore, the method can be used for other appliances without any major modification

Method for calculating annual energy efficiency improvement of TV sets

Energy Technology Data Exchange (ETDEWEB)

Varman, M. [Department of Mechanical Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Mahlia, T.M.I. [Department of Mechanical Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)]. E-mail: indra@um.edu.my; Masjuki, H.H. [Department of Mechanical Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)

2006-10-15

The popularization of 24 h pay-TV, interactive video games, web-TV, VCD and DVD are poised to have a large impact on overall TV electricity consumption in the Malaysia. Following this increased consumption, energy efficiency standard present a highly effective measure for decreasing electricity consumption in the residential sector. The main problem in setting energy efficiency standard is identifying annual efficiency improvement, due to the lack of time series statistical data available in developing countries. This study attempts to present a method of calculating annual energy efficiency improvement for TV set, which can be used for implementing energy efficiency standard for TV sets in Malaysia and other developing countries. Although the presented result is only an approximation, definitely it is one of the ways of accomplishing energy standard. Furthermore, the method can be used for other appliances without any major modification.

Device Performance and Reliability Improvements of AlGaBN/GaN/Si MOSFET

Science.gov (United States)

2016-02-04

AFRL-AFOSR-JP-TR-2016-0037 Device Performance and Reliablity Improvements of AlGaBN/GaN/Si MOSFET Robert Wallace UNIVERSITY OF TEXAS AT DALLAS Final...GaN/Si MOSFET 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386-14-1-4069 5c.  PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Robert Wallace 5d.  PROJECT...AOARD Grant FA2386-14-1-4069 Device Performance and Reliability Improvements of AlGaN/GaN/Si MOSFET US 12 month extension (2014 – 2015) for current

Efficient white organic light-emitting devices using a thin 4,4'-bis(2,2'-diphenylvinyl)-1,1'-diphenyl layer

International Nuclear Information System (INIS)

Wang Jun; Yu Junsheng; Li Lu; Tang Xiaoqing; Jiang Yadong

2008-01-01

White organic light-emitting devices (OLEDs) were fabricated using phosphorescent material bis[2-(4-tert-butylphenyl)benzothiazolato-N,C 2' ]iridium (acetylacetonate) [(t-bt) 2 Ir(acac)] doped in 4,4'-bis(carbazol-9-yl) biphenyl (CBP) matrix as a yellow light-emitting layer and a thin layer 4,4'-bis(2,2'-diphenylvinyl)-1,1'-diphenyl (DPVBi) as the blue light-emitting layer. The light colour of the OLEDs can be adjusted by changing doped concentration and the thickness of the DPVBi thin layer. The maximum luminance and power efficiency of 5% doped device reached 15 460 cd m -2 and 8.1 lm W -1 , respectively. The 3% doped device showed the CIE coordinates of (0.344, 0.322) at 8 V and a maximum power efficiency of 5.7 lm W -1 at 4.5 V

Variable cross-section windings for efficiency improvement of electric machines

Science.gov (United States)

Grachev, P. Yu; Bazarov, A. A.; Tabachinskiy, A. S.

2018-02-01

Implementation of energy-saving technologies in industry is impossible without efficiency improvement of electric machines. The article considers the ways of efficiency improvement and mass and dimensions reduction of electric machines with electronic control. Features of compact winding design for stators and armatures are described. Influence of compact winding on thermal and electrical process is given. Finite element method was used in computer simulation.

Scaling production and improving efficiency in DEA: an interactive approach

Science.gov (United States)

Rödder, Wilhelm; Kleine, Andreas; Dellnitz, Andreas

2017-10-01

DEA models help a DMU to detect its (in-)efficiency and to improve activities, if necessary. Efficiency is only one economic aim for a decision-maker; however, up- or downsizing might be a second one. Improving efficiency is the main topic in DEA; the long-term strategy towards the right production size should attract our attention as well. Not always the management of a DMU primarily focuses on technical efficiency but rather is interested in gaining scale effects. In this paper, a formula for returns to scale (RTS) is developed, and this formula is even applicable for interior points of technology. Particularly, technical and scale inefficient DMUs need sophisticated instruments to improve their situation. Considering RTS as well as efficiency, in this paper, we give an advice for each DMU to find an economically reliable path from its actual situation to better activities and finally to most productive scale size (mpss), perhaps. For realizing this path, we propose an interactive algorithm, thus harmonizing the scientific findings and the interests of the management. Small numerical examples illustrate such paths for selected DMUs; an empirical application in theatre management completes the contribution.

Efficient Signature Based Malware Detection on Mobile Devices

Directory of Open Access Journals (Sweden)

Deepak Venugopal

2008-01-01

Full Text Available The threat of malware on mobile devices is gaining attention recently. It is important to provide security solutions to these devices before these threats cause widespread damage. However, mobile devices have severe resource constraints in terms of memory and power. Hence, even though there are well developed techniques for malware detection on the PC domain, it requires considerable effort to adapt these techniques for mobile devices. In this paper, we outline the considerations for malware detection on mobile devices and propose a signature based malware detection method. Specifically, we detail a signature matching algorithm that is well suited for use in mobile device scanning due to its low memory requirements. Additionally, the matching algorithm is shown to have high scanning speed which makes it unobtrusive to users. Our evaluation and comparison study with the well known Clam-AV scanner shows that our solution consumes less than 50% of the memory used by Clam-AV while maintaining a fast scanning rate.

Bait station devices can improve mass trapping performance for the control of the Mediterranean fruit fly

OpenAIRE

Navarro-Llopis, Vicente; Primo Millo, Jaime; Vacas González, Sandra

2015-01-01

BACKGROUNDThe use of traps and other attract-and-kill devices in pest management strategies to reduce Mediterranean fruit fly populations has proved to be efficient. Nevertheless, many farmers are concerned about the effect of these devices on the trees where they are hung. Direct field observations have revealed that fruit damage is higher in trees with traps than in trees without them. This work evaluates the efficacy of different types of attract-and-kill device to protect fruit of the sin...

Towards low cost, efficient and stable organic photovoltaic modules

Energy Technology Data Exchange (ETDEWEB)

Andriessen, R. [Holst Centre - Solliance, PO Box 8550, 5605 KN Eindhoven (Netherlands); Kroon, J.M. [ECN - Solliance, Petten (Netherlands); Aernouts, T. [Imec, Solliance, Kapeldreef 75, B-3001 Leuven (Belgium); Janssen, R. [Eindhoven University of Technology, Solliance, Eindhoven (Netherlands)

2012-09-15

This article describes how the Solliance Organic PhotoVoltaics (OPV) shared research Program addresses efficiency, lifetime and production costs for (near) future OPV applications. The balance of these three parameters depends of the envisaged application, but at the end, OPV should be able to compete somehow with Si PV in the future. Efficiency improvements are realized by developing new materials, by exploring and optimizing new device structures and novel interconnection technologies. Lifetime improvements are realized by using stabilized device stacks and materials and by applying high end flexible barriers. Production cost control is done by using a home made Cost of Ownership tool which guides towards the use of low-cost materials and processes.

Efficient Device-Independent Entanglement Detection for Multipartite Systems

Science.gov (United States)

Baccari, F.; Cavalcanti, D.; Wittek, P.; Acín, A.

2017-04-01

Entanglement is one of the most studied properties of quantum mechanics for its application in quantum information protocols. Nevertheless, detecting the presence of entanglement in large multipartite states continues to be a great challenge both from the theoretical and the experimental point of view. Most of the known methods either have computational costs that scale inefficiently with the number of particles or require more information on the state than what is attainable in everyday experiments. We introduce a new technique for entanglement detection that provides several important advantages in these respects. First, it scales efficiently with the number of particles, thus allowing for application to systems composed by up to few tens of particles. Second, it needs only the knowledge of a subset of all possible measurements on the state, therefore being apt for experimental implementation. Moreover, since it is based on the detection of nonlocality, our method is device independent. We report several examples of its implementation for well-known multipartite states, showing that the introduced technique has a promising range of applications.

Efficiency Improvement and Quality Initiatives Application in Financial Institutions

Directory of Open Access Journals (Sweden)

MSc. Ajtene Avdullahi

2015-06-01

Full Text Available Financial institutions in today’s economy have no longer the luxury to improve profit simply by increasing revenue. These firms, due to the significant measuring reductions in the financial services industry needed to improve operational efficiencies and merely support existing processes with fewer resources. This paper explains the benefits of Lean, Six Sigma, Total Quality Management and Lean Six Sigma that have improved organization's performance, by cutting costs and waste, improving their products or services, increasing profitability as well as enhancing customer satisfaction. The applicability of quality management practices in financial institutions in Kosovo is presented and also their efficiency and effectiveness. By analyzing data from Raiffeisen Bank Kosovo, this paper highlights the benefits of Individual and Micro companies customer segment as the result of organizational change and successful application of quality initiatives from financial institutions in Kosovo.

Efficient CsF interlayer for high and low bandgap polymer solar cell

Science.gov (United States)

Mitul, Abu Farzan; Sarker, Jith; Adhikari, Nirmal; Mohammad, Lal; Wang, Qi; Khatiwada, Devendra; Qiao, Qiquan

2018-02-01

Low bandgap polymer solar cells have a great deal of importance in flexible photovoltaic market to absorb sun light more efficiently. Efficient wide bandgap solar cells are always available in nature to absorb visible photons. The development and incorporation of infrared photovoltaics (IR PV) with wide bandgap solar cells can improve overall solar device performance. Here, we have developed an efficient low bandgap polymer solar cell with CsF as interfacial layer in regular structure. Polymer solar cell devices with CsF shows enhanced performance than Ca as interfacial layer. The power conversion efficiency of 4.5% has been obtained for PDPP3T based polymer solar cell with CsF as interlayer. Finally, an optimal thickness with CsF as interfacial layer has been found to improve the efficiency in low bandgap polymer solar cells.

Wearable Devices in Medical Internet of Things: Scientific Research and Commercially Available Devices.

Science.gov (United States)

Haghi, Mostafa; Thurow, Kerstin; Stoll, Regina

2017-01-01

Wearable devices are currently at the heart of just about every discussion related to the Internet of Things. The requirement for self-health monitoring and preventive medicine is increasing due to the projected dramatic increase in the number of elderly people until 2020. Developed technologies are truly able to reduce the overall costs for prevention and monitoring. This is possible by constantly monitoring health indicators in various areas, and in particular, wearable devices are considered to carry this task out. These wearable devices and mobile apps now have been integrated with telemedicine and telehealth efficiently, to structure the medical Internet of Things. This paper reviews wearable health care devices both in scientific papers and commercial efforts. MIoT is demonstrated through a defined architecture design, including hardware and software dealing with wearable devices, sensors, smart phones, medical application, and medical station analyzers for further diagnosis and data storage. Wearables, with the help of improved technology have been developed greatly and are considered reliable tools for long-term health monitoring systems. These are applied in the observation of a large variety of health monitoring indicators in the environment, vital signs, and fitness. Wearable devices are now used for a wide range of healthcare observation. One of the most important elements essential in data collection is the sensor. During recent years with improvement in semiconductor technology, sensors have made investigation of a full range of parameters closer to realization.

Highly Efficient Flexible Quantum Dot Solar Cells with Improved Electron Extraction Using MgZnO Nanocrystals.

Science.gov (United States)

Zhang, Xiaoliang; Santra, Pralay Kanti; Tian, Lei; Johansson, Malin B; Rensmo, Håkan; Johansson, Erik M J

2017-08-22

Colloidal quantum dot (CQD) solar cells have high potential for realizing an efficient and lightweight energy supply for flexible or wearable electronic devices. To achieve highly efficient and flexible CQD solar cells, the electron transport layer (ETL), extracting electrons from the CQD solid layer, needs to be processed at a low-temperature and should also suppress interfacial recombination. Herein, a highly stable MgZnO nanocrystal (MZO-NC) layer is reported for efficient flexible PbS CQD solar cells. Solar cells fabricated with MZO-NC ETL give a high power conversion efficiency (PCE) of 10.4% and 9.4%, on glass and flexible plastic substrates, respectively. The reported flexible CQD solar cell has the record efficiency to date of flexible CQD solar cells. Detailed theoretical simulations and extensive characterizations reveal that the MZO-NCs significantly enhance charge extraction from CQD solids and diminish the charge accumulation at the ETL/CQD interface, suppressing charge interfacial recombination. These important results suggest that the low-temperature processed MZO-NCs are very promising for use in efficient flexible solar cells or other flexible optoelectronic devices.

Reactor power control device

International Nuclear Information System (INIS)

Ishii, Yoshihiko; Arita, Setsuo; Miyamoto, Yoshiyuki; Fukazawa, Yukihisa; Ishii, Kazuhiko

1998-01-01

The present invention provides a reactor power control device capable of enhancing an operation efficiency while keeping high reliability and safety in a BWR type nuclear power plant. Namely, the device of the present invention comprises (1) a means for inputting a set value of a generator power and a set value of a reactor power, (2) a means for controlling the reactor power to either smaller one of the reactor power corresponding to the set value of the generator power and the set value of the reactor power. With such procedures, even if the nuclear power plant is set so as to operate it to make the reactor power 100%, when the generator power reaches the upper limit, the reactor power is controlled with a preference given to the upper limit value of the generator power. Accordingly, safety and reliability are not deteriorated. The operation efficiency of the plant can be improved. (I.S.)

Efficient red phosphorescent organic light emitting diodes with double emission layers

International Nuclear Information System (INIS)

Ben Khalifa, M; Mazzeo, M; Maiorano, V; Mariano, F; Carallo, S; Melcarne, A; Cingolani, R; Gigli, G

2008-01-01

We demonstrate efficient red phosphorescent organic light emitting diodes with a bipolar emission structure (D-EML) formed by two different layers doped with a red phosphorescent dye. Due to its self-balancing character, the recombination zone is shifted far from the emission/carrier-blocking-layer interfaces. This prevents the accumulation of carriers at the interfaces and reduces the triplet-triplet annihilation, resulting in an improved efficiency of the D-EML device compared with the standard single-EML architecture. However, a current efficiency of 8.4 cd A -1 at 10 mA cm -2 is achieved in the D-EML device compared with 3.7 cd A -1 in the single-EML device

Efficient red phosphorescent organic light emitting diodes with double emission layers

Energy Technology Data Exchange (ETDEWEB)

Ben Khalifa, M; Mazzeo, M; Maiorano, V; Mariano, F; Carallo, S; Melcarne, A; Cingolani, R; Gigli, G [NNL, National Nanotechnology Laboratory of CNR-INFM, Distretto tecnologico ISUFI, Universita del Salento, Italy, Via per Arnesano, Km.5, 73100 Lecce (Italy)], E-mail: mohamed.benkhalifa@unile.it

2008-08-07

We demonstrate efficient red phosphorescent organic light emitting diodes with a bipolar emission structure (D-EML) formed by two different layers doped with a red phosphorescent dye. Due to its self-balancing character, the recombination zone is shifted far from the emission/carrier-blocking-layer interfaces. This prevents the accumulation of carriers at the interfaces and reduces the triplet-triplet annihilation, resulting in an improved efficiency of the D-EML device compared with the standard single-EML architecture. However, a current efficiency of 8.4 cd A{sup -1} at 10 mA cm{sup -2} is achieved in the D-EML device compared with 3.7 cd A{sup -1} in the single-EML device.

Utilization of information and communications technology (ICT) to improve workface efficiency

Energy Technology Data Exchange (ETDEWEB)

Haines, A.; Rasmussen, J. [Industrial Audit Corp., Toronto, Ontario (Canada)

2010-07-01

Improving the efficiency of personnel at the workface is a key objective for executing construction, maintenance, quality, engineering and human performance activities. Schedule and cost overruns have a significant impact on the bottom line and on future business efficiency in execution of tasks is paramount to success. Leveraging information and communications technology (ICT) in construction, maintenance and operation environments can create a mobile workforce where personnel efficiency is improved, significant gains are made on schedule and cost, and the overall quality of work is raised. This paper will discuss the impact of mobile technology specifically on workface efficiency and productivity. (author)

Utilization of information and communications technology (ICT) to improve workface efficiency

International Nuclear Information System (INIS)

Haines, A.; Rasmussen, J.

2010-01-01

Improving the efficiency of personnel at the workface is a key objective for executing construction, maintenance, quality, engineering and human performance activities. Schedule and cost overruns have a significant impact on the bottom line and on future business efficiency in execution of tasks is paramount to success. Leveraging information and communications technology (ICT) in construction, maintenance and operation environments can create a mobile workforce where personnel efficiency is improved, significant gains are made on schedule and cost, and the overall quality of work is raised. This paper will discuss the impact of mobile technology specifically on workface efficiency and productivity. (author)

Improvement in light-extraction efficiency of light emitting diode ...

Indian Academy of Sciences (India)

The effect of various microlens parameters such as diameter and area fraction on light-extraction efficiency was systematically studied. Improvement of 4% in extraction efficiency was obtained by employing it on white light emitting diode. The area fraction of microlenses was increased up to 0.34 by reducing the spin speed.

Refractories for Industrial Processing. Opportunities for Improved Energy Efficiency

Energy Technology Data Exchange (ETDEWEB)

Hemrick, James G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hayden, H. Wayne [Metals Manufacture Process and Controls Technology, Inc., Oak Ridge, TN (United States); Angelini, Peter [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Moore, Robert E. [R.E. Moore Associates, Maricopa, AZ (United States); Headrick, William L. [R.E. Moore Associates, Maricopa, AZ (United States)

2005-01-01

Refractories are a class of materials of critical importance to manufacturing industries with high-temperature unit processes. This study describes industrial refractory applications and identifies refractory performance barriers to energy efficiency for processing. The report provides recommendations for R&D pathways leading to improved refractories for energy-efficient manufacturing and processing.

Simulations of backgate sandwich nanowire MOSFETs with improved device performance

International Nuclear Information System (INIS)

Zhao Hengliang; Zhu Huilong; Zhong Jian; Ma Xiaolong; Wei Xing; Zhao Chao; Chen Dapeng; Ye Tianchun

2014-01-01

We propose a novel backgate sandwich nanowire MOSFET (SNFET), which offers the advantages of ETSOI (dynamic backgate voltage controllability) and nanowire FETs (good short channel effect). A backgate is used for threshold voltage (V t ) control of the SNFET. Compared with a backgate FinFET with a punch-through stop layer (PTSL), the SNFET possesses improved device performance. 3D device simulations indicate that the SNFET has a three times larger overdrive current, a ∼75% smaller off leakage current, and reduced subthreshold swing (SS) and DIBL than those of a backgate FinFET when the nanowire (NW) and the fin are of equal width. A new process flow to fabricate the backgate SNFET is also proposed in this work. Our analytical model suggests that V t control by the backgate can be attributed to the capacitances formed by the frontgate, NW, and backgate. The SNFET devices are compatible with the latest state-of-the-art high-k/metal gate CMOS technology with the unique capability of independent backgate control for nFETs and pFETs, which is promising for sub-22 nm scaling down. (semiconductor devices)

Improvement of the center boring device for the irradiated fuel pellets

Energy Technology Data Exchange (ETDEWEB)

Usami, Koji; Onozawa, Atsushi; Kimura, Yasuhiko; Sakuraba, Naotoshi; Shiina, Hidenori; Harada, Akito; Nakata, Masahito [Japan Atomic Energy Agency, Nuclear Science Research Inst., Tokai, Ibaraki (Japan)

2012-03-15

The power ramp tests performed at JMTR in Oarai R and D Center are objected to study the safety margin of the high burnup fuels. One of the important parameters measured during this test is the center temperature of the fuel pellet. For this measurement, a thermocouple is installed into the hole bored at the pellet center by the center boring device, which can fix the fuel pellet with the frozen CO{sub 2} gas during its boring process. At the Reactor Fuel Examination Facility (RFEF) in Tokai R and D Center, several improvements were applied for the previous boring device to gain its performance and reliability. The major improvements are the change of the drill bit, modification of the boring process and the optimization of the remote operability. The mock-up test will be performed with the irradiated fuel pellet to confirm the benefit of improvement. This study was conducted under a contract with the Nuclear and Industrial Safety Agency (NISA) of the Ministry of Economy, Trade and Industry (METI). (author)

Device-to-Device Underlay Cellular Networks with Uncertain Channel State Information

KAUST Repository

Memmi, Amen

2016-01-06

Device-to-Device (D2D) communications underlying the cellular infrastructure is a technology that has recently been proposed as a promising solution to enhance cellular network capabilities: It improves spectrum utilization, overall throughput and energy efficiency while enabling new peer-to-peer and location-based applications and services. However, interference is the major challenge since the same resources are shared by both systems. Therefore, interference management techniques are required to keep the interference under control. In this work, in order to mitigate interference, we consider centralized and distributed power control algorithms in a one-cell random network model. Differently from previous works, we are assuming that the channel state information (CSI) may be imperfect and include estimation errors. We evaluate how this uncertainty impacts performances.

Improvement of light harvesting and device performance of dye-sensitized solar cells using rod-like nanocrystal TiO{sub 2} overlay coating on TiO{sub 2} nanoparticle working electrode

Energy Technology Data Exchange (ETDEWEB)

Liu, Xueyang; Fang, Jian [Institute for Frontier Materials, Deakin University, VIC 3220 (Australia); Gao, Mei [CSIRO Materials Science and Engineering, Melbourne, VIC 3169 (Australia); Wang, Hongxia [Institute for Frontier Materials, Deakin University, VIC 3220 (Australia); Yang, Weidong [CSIRO Materials Science and Engineering, Melbourne, VIC 3169 (Australia); Lin, Tong, E-mail: tong.lin@deakin.edu.au [Institute for Frontier Materials, Deakin University, VIC 3220 (Australia)

2015-02-01

Novel TiO{sub 2} single crystalline nanorods were synthesized by electrospinning and hydrothermal treatment. The role of the TiO{sub 2} nanorods on TiO{sub 2} nanoparticle electrode in improvement of light harvesting and photovoltaic properties of dye-sensitized solar cells (DSSCs) was examined. Although the TiO{sub 2} nanorods had lower dye loading than TiO{sub 2} nanoparticle, they showed higher light utilization behaviour. Electron transfer in TiO{sub 2} nanorods received less resistance than that in TiO{sub 2} nanoparticle aggregation. By just applying a thin layer of TiO{sub 2} nanorods on TiO{sub 2} nanoparticle working electrode, the DSSC device light harvesting ability and energy conversion efficiency were improved significantly. The thickness of the nanorod layer in the working electrode played an important role in determining the photovoltaic property of DSSCs. An energy conversion efficiency as high as 6.6% was found on a DSSC device with the working electrode consisting of a 12 μm think TiO{sub 2} nanoparticle layer covered with 3 μm thick TiO{sub 2} nanorods. The results obtained from this study may benefit further design of highly efficient DSSCs. - Highlights: • Single crystalline TiO{sub 2} nanorods were prepared for DSSC application. • TiO{sub 2} nanorods show effective light scattering performance. • TiO{sub 2} nanorods have higher electron transfer efficiency than TiO{sub 2} nanoparticles. • TiO{sub 2} nanorods on TiO{sub 2} nanoparticle electrode improve DSSC efficiency.

Effectiveness of the stormwater quality devices to improve water quality at Putrajaya

International Nuclear Information System (INIS)

Sidek, L M; Basri, H; Puad, A H Mohd; Noh, M N Md; Ainan, A

2013-01-01

Development of Putrajaya has changed the character of the natural landform by covering the land with impervious surfaces. Houses, office buildings, commercial place and shopping centres have provided places to live and work. The route between buildings is facilitated and encouraged by a complex network of roads and car parks. However, this change from natural landforms and vegetative cover to impervious surfaces has major effect on stormwater which are water quality (non-point source pollution). This paper describes the effectiveness of the stormwater quality devices to improve water quality at selected Putrajaya for demonstration in order to evaluate low cost storm inlet type devices in the Putrajaya Catchment. Five stormwater quality devices were installed and monitored during the study. The devices include Ultra Drain Guard Recycle model, Ultra Curb Guard Plus, Ultra Grate Guard, Absorbent Tarp and Ultra Passive Skimmer. This paper will provide information on the benefits and costs of these devices, including operations and maintenance requirements. Applicability of these devices in gas stations, small convenience stores, residential and small parking lots in the catchment are possible due to their low cost.

Barriers to efficiency improvement and fuel switching in Karnataka, India

International Nuclear Information System (INIS)

Reddy, A.

1991-01-01

Implementing energy efficiency changes requires a wide range measures. Improvements, therefore, require actions at the lowest level of the consumer, through the highest level of the global agencies. Due to the multiplicity of participants, however, barriers to achieving these improvements can arise at every level. The major barriers to improving energy efficiency in developing countries are defined and paths to overcome these challenges are identified. Topics of discussion include: energy consumers; end-use equipment manufacturers; end-use equipment providers; energy carrier producers and distributors; actual/potential cogenerators; financial institutions; government; and international, multilateral and industrialized country funding/aid agencies

Improvement of Metal-Graphene Ohmic Contact Resistance in Bilayer Epitaxial Graphene Devices

International Nuclear Information System (INIS)

He Ze-Zhao; Yang Ke-Wu; Yu Cui; Li Jia; Liu Qing-Bin; Lu Wei-Li; Feng Zhi-Hong; Cai Shu-Jun

2015-01-01

We report on an improved metal-graphene ohmic contact in bilayer epitaxial graphene on a SiC substrate with contact resistance below 0.1 ω·mm. Monolayer and bilayer epitaxial graphenes are prepared on a 4H-SiC substrate in this work. Their contact resistances are measured by a transfer length method. An improved photoresist-free device fabrication method is used and is compared with the conventional device fabrication method. Compared with the monolayer graphene, the contact resistance R c of bilayer graphene improves from an average of 0.24 ω·mm to 0.1 ω·mm. Ohmic contact formation mechanism analysis by Landauer's approach reveals that the obtained low ohmic contact resistance in bilayer epitaxial graphene is due to their high carrier density, high carrier transmission probability, and p-type doping introduced by contact metal Au. (paper)

Improving Energy Efficiency In Thermal Oil Recovery Surface Facilities

Energy Technology Data Exchange (ETDEWEB)

Murthy Nadella, Narayana

2010-09-15

Thermal oil recovery methods such as Cyclic Steam Stimulation (CSS), Steam Assisted Gravity Drainage (SAGD) and In-situ Combustion are being used for recovering heavy oil and bitumen. These processes expend energy to recover oil. The process design of the surface facilities requires optimization to improve the efficiency of oil recovery by minimizing the energy consumption per barrel of oil produced. Optimization involves minimizing external energy use by heat integration. This paper discusses the unit processes and design methodology considering thermodynamic energy requirements and heat integration methods to improve energy efficiency in the surface facilities. A design case study is presented.

A primer on the energy efficiency of computing

Energy Technology Data Exchange (ETDEWEB)

Koomey, Jonathan G. [Research Fellow, Steyer-Taylor Center for Energy Policy and Finance, Stanford University (United States)

2015-03-30

The efficiency of computing at peak output has increased rapidly since the dawn of the computer age. This paper summarizes some of the key factors affecting the efficiency of computing in all usage modes. While there is still great potential for improving the efficiency of computing devices, we will need to alter how we do computing in the next few decades because we are finally approaching the limits of current technologies.

Energy-Efficiency Improvement Opportunities for the Textile Industry

Energy Technology Data Exchange (ETDEWEB)

China Energy Group; Hasanbeigi, Ali

2010-09-29

The textile industry is one of the most complicated manufacturing industries because it is a fragmented and heterogeneous sector dominated by small and medium enterprises (SMEs). Energy is one of the main cost factors in the textile industry. Especially in times of high energy price volatility, improving energy efficiency should be a primary concern for textile plants. There are various energy-efficiency opportunities that exist in every textile plant, many of which are cost-effective. However, even cost-effective options often are not implemented in textile plants mostly because of limited information on how to implement energy-efficiency measures, especially given the fact that a majority of textile plants are categorized as SMEs and hence they have limited resources to acquire this information. Know-how on energy-efficiency technologies and practices should, therefore, be prepared and disseminated to textile plants. This guidebook provides information on energy-efficiency technologies and measures applicable to the textile industry. The guidebook includes case studies from textile plants around the world and includes energy savings and cost information when available. First, the guidebook gives a brief overview of the textile industry around the world, with an explanation of major textile processes. An analysis of the type and the share of energy used in different textile processes is also included in the guidebook. Subsequently, energy-efficiency improvement opportunities available within some of the major textile sub-sectors are given with a brief explanation of each measure. The conclusion includes a short section dedicated to highlighting a few emerging technologies in the textile industry as well as the potential for the use of renewable energy in the textile industry.

Improving health and energy efficiency through community-based housing interventions.

Science.gov (United States)

Howden-Chapman, Philippa; Crane, Julian; Chapman, Ralph; Fougere, Geoff

2011-12-01

Houses designed for one climate and cultural group may not be appropriate for other places and people. Our aim is to find cost-effective ways to improve the characteristics of older homes, ill-fitted for New Zealand's climate, in order to improve the occupants' health. We have carried out two community randomised trials, in partnership with local communities, which have focused on retrofitted insulation and more effective heating and have two other studies under way, one which focuses on electricity vouchers and the other on housing hazard remediation. The Housing, Insulation and Health Study showed that insulating 1,350 houses, built before insulation was required, improved the occupants' health and well being as well as household energy efficiency. In the Housing, Heating and Health Study we investigated the impact of installing more effective heating in insulated houses for 409 households, where there was a child with doctor-diagnosed asthma. Again, the study showed significant results in the intervention group; indoor temperatures increased and levels of NO(2) were halved. Children reported less poor health, lower levels of asthma symptoms and sleep disturbances by wheeze and dry cough. Children also had fewer days off school. Improving the energy efficiency of older housing leads to health improvements and energy efficiency improvements. Multidisciplinary studies of housing interventions can create compelling evidence to support policies for sustainable housing developments which improve health.

An Energy Saving Green Plug Device for Nonlinear Loads

Science.gov (United States)

Bloul, Albe; Sharaf, Adel; El-Hawary, Mohamed

2018-03-01

The paper presents a low cost a FACTS Based flexible fuzzy logic based modulated/switched tuned arm filter and Green Plug compensation (SFC-GP) scheme for single-phase nonlinear loads ensuring both voltage stabilization and efficient energy utilization. The new Green Plug-Switched filter compensator SFC modulated LC-Filter PWM Switched Capacitive Compensation Devices is controlled using a fuzzy logic regulator to enhance power quality, improve power factor at the source and reduce switching transients and inrush current conditions as well harmonic contents in source current. The FACTS based SFC-GP Device is a member of family of Green Plug/Filters/Compensation Schemes used for efficient energy utilization, power quality enhancement and voltage/inrush current/soft starting control using a dynamic error driven fuzzy logic controller (FLC). The device with fuzzy logic controller is validated using the Matlab / Simulink Software Environment for enhanced power quality (PQ), improved power factor and reduced inrush currents. This is achieved using modulated PWM Switching of the Filter-Capacitive compensation scheme to cope with dynamic type nonlinear and inrush cyclical loads..

Efficiency Improvement of HIT Solar Cells on p-Type Si Wafers.

Science.gov (United States)

Wei, Chun-You; Lin, Chu-Hsuan; Hsiao, Hao-Tse; Yang, Po-Chuan; Wang, Chih-Ming; Pan, Yen-Chih

2013-11-22

Single crystal silicon solar cells are still predominant in the market due to the abundance of silicon on earth and their acceptable efficiency. Different solar-cell structures of single crystalline Si have been investigated to boost efficiency; the heterojunction with intrinsic thin layer (HIT) structure is currently the leading technology. The record efficiency values of state-of-the art HIT solar cells have always been based on n-type single-crystalline Si wafers. Improving the efficiency of cells based on p-type single-crystalline Si wafers could provide broader options for the development of HIT solar cells. In this study, we varied the thickness of intrinsic hydrogenated amorphous Si layer to improve the efficiency of HIT solar cells on p-type Si wafers.

[Study on the reform and improvement of the medical device registration system in China].

Science.gov (United States)

Wang, Lanming

2012-11-01

Based on the theories of the Government Regulation and Administrative Licensure, aiming at the current situations of medical device registration system in China, some policy suggestions for future reform and improvement were provided as follows. (1) change the concepts of medical device registration administration. (2) perfect the regulations of medical device registration administration. (3) reform the medical device review organizational system. (4) Optimize the procedure of review and approval. (5) set up and maintain a professional team of review and approval staff. (6) reinforce the post-marketing supervision of medical devices. (7) foster and bring into play of the role of non-government organizations.

An Efficient and Secure m-IPS Scheme of Mobile Devices for Human-Centric Computing

OpenAIRE

Jeong, Young-Sik; Lee, Jae Dong; Lee, Jeong-Bae; Jung, Jai-Jin; Park, Jong Hyuk

2014-01-01

Recent rapid developments in wireless and mobile IT technologies have led to their application in many real-life areas, such as disasters, home networks, mobile social networks, medical services, industry, schools, and the military. Business/work environments have become wire/wireless, integrated with wireless networks. Although the increase in the use of mobile devices that can use wireless networks increases work efficiency and provides greater convenience, wireless access to networks repre...

Single-doped white organic light-emitting device with an external quantum efficiency over 20%.

Science.gov (United States)

Fleetham, Tyler; Ecton, Jeremy; Wang, Zixing; Bakken, Nathan; Li, Jian

2013-05-14

A white OLED with a maximum EQE of 20.1%, CIE coordinates of (0.33, 0.33) and CRI of 80 is fabricated based on platinum(II) bis(N-methyl-imidazolyl)benzene chloride (Pt-16). The device emission spectrum and the chemical structure of Pt-16 are shown in the inset of the efficiency versus luminance graph. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Improving 200 MW NDHR reactor protection system with GAL devices

International Nuclear Information System (INIS)

Shi Mingde; Li Duo; Xie Zhengguo

1999-01-01

The emergence of General Array Logic (GAL), a fairly new type of logic devices with the characteristics of user-definable logic functions, have led to a revolutionary change in the design of logical circuits. The improvements of the reactor protection system for the 200 MW nuclear district heating reactor (NDHR) using GAL are covered

Alternating Copolymers and Alternative Device Geometries for Organic Photovoltaics

OpenAIRE

Inganäs, Olle; Zhang, Fengling; Andersson, Mats R.

2012-01-01

The efficiency of conversion of light to electrical energy with the help of conjugated polymers and molecules is rapidly improving. The optical absorption properties of these materials can be designed, and implemented via molecular engineering. Full coverage of the solar spectrum is thus feasible. Narrow absorption spectra allow construction of tandem solar cells. The poor transport properties of these materials require thin devices, which limits optical absorption. Alternative device geometr...

Improved survival of macroencapsulated islets of Langerhans by preimplantation of the immunoisolating device: a morphometric study.

Science.gov (United States)

Rafael, E; Wu, G S; Hultenby, K; Tibell, A; Wernerson, A

2003-01-01

Encapsulation of cells in a semipermeable membrane may in the future provide an opportunity to treat a variety of endocrine and neurological disorders, without the need for lifelong immunosuppression. The physiological conditions in the device are crucial factors for graft survival. Previously, we have shown that the exchange across the immunoisolating membrane and the microcirculation around the TheraCyte device increase around 3 months after implantation. The aim of this study was to determine whether preimplantation of the TheraCyte device would improve the survival of a later transplanted islet graft. A TheraCyte device was implanted SC on one side of the back of a nondiabetic SD rat. After 3 months, 1500 islets isolated from SD rats were transplanted via the device port. At the same time, another device, loaded with the same number of islets, was implanted on the other side of the back. Both devices were explanted 2 weeks after islet transplantation (i.e., 3.5 months and 0.5 month after device implantation, respectively). Six pairs of devices were evaluated by morphometery. The volume densities of viable islets were 0.22 +/- 0.04 in the preimplanted device vs. 0.06 +/- 0.03 in the nonpreimplanted one (p TheraCyte device seems to improve the survival of an encapsulated islet graft and reduce fibroblast outgrowth in the device.

Residential carbon dioxide emissions in Canada. Impact of efficiency improvements and fuel substitution

International Nuclear Information System (INIS)

Ugursal, V.I.; FUng, A.S.

1998-01-01

The effect of improving house envelope, heating system and appliance efficiencies, and fuel substitution on the atmospheric emissions of carbon dioxide in the Canadian residential sector is studied based on simulation studies. The findings clearly indicate that improving appliance efficiency reduces the overall end-use energy consumption in the residential sector as well as the associated carbon dioxide emissions. However, the magnitude of the reduction in carbon dioxide emissions as a result of improving only appliance efficiencies is quite small. Significantly larger reductions can be obtained by improving house envelopes and heating/cooling systems in addition to improving appliance efficiencies. Fuel substitution for space and domestic hot water heating can also present a potential to reduce carbon dioxide emissions depending on the fuel substitution scenario adopted. (author)

Does Automation Improve Stock Market Efficiency? Evidence from Ghana

OpenAIRE

Mensah, Justice T.; Pomaa-Berko, Maame; Adom, Philip Kofi

2012-01-01

As a burgeoning capital market in an emerging economy, automation of the stock market is regarded as a major step towards integrating the financial market as a conduit for economic growth. The automation of the Ghana Stock Exchange (GSE) in 2008 is expected among other things to improve the efficiency of the market. This paper therefore investigates the impact of the automation on the efficiency of the GSE within the framework of the weak-form Efficient Market Hypothesis (EMH) using daily mar...

Prior-knowledge-independent equalization to improve battery uniformity with energy efficiency and time efficiency for lithium-ion battery

International Nuclear Information System (INIS)

Zhang, Shumei; Qiang, Jiaxi; Yang, Lin; Zhao, Xiaowei

2016-01-01

To improve battery uniformity as well as energy efficiency and time efficiency, a SOC (state of charge)-based equalization by AGA (adaptive genetic algorithm) is proposed on basis of two-stage DC/DC converters. The simulation results indicate that compared with FLC (fuzzy logic controller) equalization, the standard deviation of final SOC is improved by 78.7% while energy efficiency is improved by 6.01% and equalization time is decreased by 20% for AGA equalization of extreme dispersion. Additionally, AGA improves the battery uniformity by 30.77% with shortening equalization time by 16.29% and saving energy loss by 1.51% compared with FLC for equalization of regular dispersion. For further validation, the equalization optimization is verified by experiment based on the data-driven parameter identification method which is used to enhance the real-time capability of AGA. For AGA equalization of extreme dispersion, the standard deviation of final SOC is just 0.41% while equalization time prolongs only 14 min and energy efficiency is decreased by 0.81% compared with simulation results. Moreover, not only the standard deviation of final SOC is just 0.28% but also the energy efficiency is decreased by 0.69% and equalization time prolongs by 10.4 min compared with the simulation results for equalization of regular dispersion. - Highlights: • Issues of over equalization, time consumption and energy loss are addressed. • A SOC-based equalization is proposed based on adaptive genetic algorithm. • The equalization aims to improve battery uniformity, efficiency of energy and time. • Data-driven parameter identification is used to enhance the real-time capability.

Particles separation in a cyclone device cone

Directory of Open Access Journals (Sweden)

Vasilevsky Michail

2015-01-01

Full Text Available The improvement of the methods for calculating the efficiency for particles separation in these devices is the subject of article. Finding data show that the particles are discharged from the central zone to periphery by diffusive transport in the zone of high centripetal accelerations. It is found that the central zone is the ejection effect zone on the paraxial flow and intense discharge particle zone. The concentrations distribution and distribution of fractional efficiencies are presented.

The dynamic modeling and design improvement of a piezoelectric exciter of a touch screen device for efficient tactile feedback

International Nuclear Information System (INIS)

Park, Young-Min; Kim, Kwang-Joon

2011-01-01

Piezoelectric exciters have been receiving greater attention recently as a vibration source for tactile feedback in devices with touch screens, such as a mobile phones, in place of DC motors due to lower energy consumption and smaller volume. Their insufficient excitation level, however, still remains a problem. In this paper, dynamic modeling and design improvement of a piezoelectric exciter are presented. The excitation performance is defined as the acceleration response at the center of a touch screen per electric power and to be maximized around 250 Hz where the index finger is most sensitive. The piezoelectric exciter consists of a z-shaped metal beam, a piezoelectric layer on the long horizontal segment and an adhesive layer between the short horizontal segment and the touch screen. Assuming that the piezoelectric exciter is attached onto a rigid ground due to its low mechanical impedance compared with that of the touch screen, the piezoelectric exciter is dynamically modeled by applying Hamilton's principle, where the adhesive layer is treated as a distributed stiffness. The touch screen is modeled approximately as a simply supported beam such that it may have the same fundamental natural frequency and bending stiffness as the screen based on measurements. The performance improvement is focused on the change of five geometric parameters of the piezoelectric exciter: length of the long horizontal segment, thickness of the piezoelectric layer, thickness of the elastic metal layer, width of the beams and tip mass. The procedure to improve the performance of the piezoelectric exciter via dynamic modeling is presented together with experimental results on a prototype. Effectiveness of the design modification and limitations in practice are further discussed as well

Improving the Efficiency of Organic Solar Cells upon Addition of Polyvinylpyridine

Directory of Open Access Journals (Sweden)

Rita Rodrigues

2014-12-01

Full Text Available We report on the efficiency improvement of organic solar cells (OPVs based on the low energy gap polyfluorene derivative, APFO-3, and the soluble C60 fullerene PCBM, upon addition of a residual amount of poly (4-vinylpyridine (PVP. We find that the addition of 1% by weight of PVP with respect to the APFO-3 content leads to an increase of efficiency from 2.4% to 2.9%. Modifications in the phase separation details of the active layer were investigated as a possible origin of the efficiency increase. At high concentrations of PVP, the blend morphology is radically altered as observed by Atomic Force Microscopy. Although the use of low molecular weight additives is a routine method to improve OPVs efficiency, this report shows that inert polymers, in terms of optical and charge transport properties, may also improve the performance of polymer-based solar cells.

Selectively Fortifying Reconfigurable Computing Device to Achieve Higher Error Resilience

Directory of Open Access Journals (Sweden)

Mingjie Lin

2012-01-01

Full Text Available With the advent of 10 nm CMOS devices and “exotic” nanodevices, the location and occurrence time of hardware defects and design faults become increasingly unpredictable, therefore posing severe challenges to existing techniques for error-resilient computing because most of them statically assign hardware redundancy and do not account for the error tolerance inherently existing in many mission-critical applications. This work proposes a novel approach to selectively fortifying a target reconfigurable computing device in order to achieve hardware-efficient error resilience for a specific target application. We intend to demonstrate that such error resilience can be significantly improved with effective hardware support. The major contributions of this work include (1 the development of a complete methodology to perform sensitivity and criticality analysis of hardware redundancy, (2 a novel problem formulation and an efficient heuristic methodology to selectively allocate hardware redundancy among a target design’s key components in order to maximize its overall error resilience, and (3 an academic prototype of SFC computing device that illustrates a 4 times improvement of error resilience for a H.264 encoder implemented with an FPGA device.

3D-printed components for quantum devices.

Science.gov (United States)

Saint, R; Evans, W; Zhou, Y; Barrett, T; Fromhold, T M; Saleh, E; Maskery, I; Tuck, C; Wildman, R; Oručević, F; Krüger, P

2018-05-30

Recent advances in the preparation, control and measurement of atomic gases have led to new insights into the quantum world and unprecedented metrological sensitivities, e.g. in measuring gravitational forces and magnetic fields. The full potential of applying such capabilities to areas as diverse as biomedical imaging, non-invasive underground mapping, and GPS-free navigation can only be realised with the scalable production of efficient, robust and portable devices. We introduce additive manufacturing as a production technique of quantum device components with unrivalled design freedom and rapid prototyping. This provides a step change in efficiency, compactness and facilitates systems integration. As a demonstrator we present an ultrahigh vacuum compatible ultracold atom source dissipating less than ten milliwatts of electrical power during field generation to produce large samples of cold rubidium gases. This disruptive technology opens the door to drastically improved integrated structures, which will further reduce size and assembly complexity in scalable series manufacture of bespoke portable quantum devices.

Study to Improve Security for IoT Smart Device Controller: Drawbacks and Countermeasures

Directory of Open Access Journals (Sweden)

Xin Su

2018-01-01

Full Text Available Including mobile environment, conventional security mechanisms have been adapted to satisfy the needs of users. However, the device environment-IoT-based number of connected devices is quite different to the previous traditional desktop PC- or mobile-based environment. Based on the IoT, different kinds of smart and mobile devices are fully connected automatically via device controller, such as smartphone. Therefore, controller must be secure compared to conventional security mechanism. According to the existing security threats, these are quite different from the previous ones. Thus, the countermeasures applied should be changed. However, the smart device-based authentication techniques that have been proposed to date are not adequate in terms of usability and security. From the viewpoint of usability, the environment is based on mobility, and thus devices are designed and developed to enhance their owners’ efficiency. Thus, in all applications, there is a need to consider usability, even when the application is a security mechanism. Typically, mobility is emphasized over security. However, considering that the major characteristic of a device controller is deeply related to its owner’s private information, a security technique that is robust to all kinds of attacks is mandatory. In this paper, we focus on security. First, in terms of security achievement, we investigate and categorize conventional attacks and emerging issues and then analyze conventional and existing countermeasures, respectively. Finally, as countermeasure concepts, we propose several representative methods.

Efficient fluorescence/phosphorescence white organic light-emitting diodes with ultra high color stability and mild efficiency roll-off

Science.gov (United States)

Du, Xiaoyang; Tao, Silu; Huang, Yun; Yang, Xiaoxia; Ding, Xulin; Zhang, Xiaohong

2015-11-01

Efficient fluorescence/phosphorescence hybrid white organic light-emitting diodes (OLEDs) with single doped co-host structure have been fabricated. Device using 9-Naphthyl-10 -(4-triphenylamine)anthrancene as the fluorescent dopant and Ir(ppy)3 and Ir(2-phq)3 as the green and orange phosphorescent dopants show the luminous efficiency of 12.4% (17.6 lm/W, 27.5 cd/A) at 1000 cd/m2. Most important to note that the efficiency-brightness roll-off of the device was very mild. With the brightness rising up to 5000 and 10 000 cd/m2, the efficiency could be kept at 11.8% (14.0 lm/W, 26.5 cd/A) and 11.0% (11.8 lm/W, 25.0 cd/A). The Commission Internationale de L'Eclairage (CIE) coordinates and color rending index (CRI) were measured to be (0.45, 0.48) and 65, respectively, and remained the same in a large range of brightness (1000-10 000 cd/m2), which is scarce in the reported white OLEDs. The performance of the device at high luminance (5000 and 10 000 cd/m2) was among the best reported results including fluorescence/phosphorescence hybrid and all-phosphorescent white OLEDs. Moreover, the CRI of the white OLED can be improved to 83 by using a yellow-green emitter (Ir(ppy)2bop) in the device.

Scope for improved eco-efficiency varies among diverse cropping systems.

Science.gov (United States)

Carberry, Peter S; Liang, Wei-li; Twomlow, Stephen; Holzworth, Dean P; Dimes, John P; McClelland, Tim; Huth, Neil I; Chen, Fu; Hochman, Zvi; Keating, Brian A

2013-05-21

Global food security requires eco-efficient agriculture to produce the required food and fiber products concomitant with ecologically efficient use of resources. This eco-efficiency concept is used to diagnose the state of agricultural production in China (irrigated wheat-maize double-cropping systems), Zimbabwe (rainfed maize systems), and Australia (rainfed wheat systems). More than 3,000 surveyed crop yields in these three countries were compared against simulated grain yields at farmer-specified levels of nitrogen (N) input. Many Australian commercial wheat farmers are both close to existing production frontiers and gain little prospective return from increasing their N input. Significant losses of N from their systems, either as nitrous oxide emissions or as nitrate leached from the soil profile, are infrequent and at low intensities relative to their level of grain production. These Australian farmers operate close to eco-efficient frontiers in regard to N, and so innovations in technologies and practices are essential to increasing their production without added economic or environmental risks. In contrast, many Chinese farmers can reduce N input without sacrificing production through more efficient use of their fertilizer input. In fact, there are real prospects for the double-cropping systems on the North China Plain to achieve both production increases and reduced environmental risks. Zimbabwean farmers have the opportunity for significant production increases by both improving their technical efficiency and increasing their level of input; however, doing so will require improved management expertise and greater access to institutional support for addressing the higher risks. This paper shows that pathways for achieving improved eco-efficiency will differ among diverse cropping systems.

Method of making an improved superconducting quantum interference device

International Nuclear Information System (INIS)

Wu, C.T.; Falco, C.M.; Kampwirth, R.T.

1977-01-01

An improved superconducting quantum interference device is made by sputtering a thin film of an alloy of three parts niobium to one part tin in a pattern comprising a closed loop with a narrow region, depositing a thin film of a radiation shield such as copper over the niobium-tin, scribing a narrow line in the copper over the narrow region, exposing the structure at the scribed line to radiation and removing the deposited copper

Concurrent improvement in optical and electrical characteristics by using inverted pyramidal array structures toward efficient Si heterojunction solar cells

KAUST Repository

Wang, Hsin Ping

2016-03-02

The Si heterojunction (SHJ) solar cell is presently the most popular design in the crystalline Si (c-Si) photovoltaics due to the high open-circuit voltages (V). Photon management by surface structuring techniques to control the light entering the devices is critical for boosting cell efficiency although it usually comes with the V loss caused by severe surface recombination. For the first time, the periodic inverted pyramid (IP) structure fabricated by photolithography and anisotropic etching processes was employed for SHJ solar cells, demonstrating concurrent improvement in optical and electrical characteristics (i.e., short-circuit current density (J) and V). Periodic IP structures show superior light-harvesting properties as most of the incident rays bounce three times on the walls of the IPs but only twice between conventional random upright pyramids (UPs). The high minority carrier lifetime of the IP structures after a-Si:H passivation results in an enhanced V by 28 mV, showing improved carrier collection efficiency due to the superior passivation of the IP structure over the random UP structures. The superior antireflective (AR) ability and passivation results demonstrate that the IP structure has the potential to replace conventional UP structures to further boost the efficiency in solar cell applications.

Improved Feature Matching for Mobile Devices with IMU

Directory of Open Access Journals (Sweden)

Andrea Masiero

2016-08-01

Full Text Available Thanks to the recent diffusion of low-cost high-resolution digital cameras and to the development of mostly automated procedures for image-based 3D reconstruction, the popularity of photogrammetry for environment surveys is constantly increasing in the last years. Automatic feature matching is an important step in order to successfully complete the photogrammetric 3D reconstruction: this step is the fundamental basis for the subsequent estimation of the geometry of the scene. This paper reconsiders the feature matching problem when dealing with smart mobile devices (e.g., when using the standard camera embedded in a smartphone as imaging sensor. More specifically, this paper aims at exploiting the information on camera movements provided by the inertial navigation system (INS in order to make the feature matching step more robust and, possibly, computationally more efficient. First, a revised version of the affine scale-invariant feature transform (ASIFT is considered: this version reduces the computational complexity of the original ASIFT, while still ensuring an increase of correct feature matches with respect to the SIFT. Furthermore, a new two-step procedure for the estimation of the essential matrix E (and the camera pose is proposed in order to increase its estimation robustness and computational efficiency.

Highly Simplified Tandem Organic Light-Emitting Devices Incorporating a Green Phosphorescence Ultrathin Emitter within a Novel Interface Exciplex for High Efficiency.

Science.gov (United States)

Xu, Ting; Zhou, Jun-Gui; Huang, Chen-Chao; Zhang, Lei; Fung, Man-Keung; Murtaza, Imran; Meng, Hong; Liao, Liang-Sheng

2017-03-29

Herein we report a novel design philosophy of tandem OLEDs incorporating a doping-free green phosphorescent bis[2-(2-pyridinyl-N)phenyl-C](acetylacetonato)iridium(III) (Ir(ppy) 2 (acac)) as an ultrathin emissive layer (UEML) into a novel interface-exciplex-forming structure of 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) and 1,3,5-tri(p-pyrid-3-yl-phenyl)benzene (TmPyPB). Particularly, relatively low working voltage and remarkable efficiency are achieved and the designed tandem OLEDs exhibit a peak current efficiency of 135.74 cd/A (EQE = 36.85%) which is two times higher than 66.2 cd/A (EQE = 17.97%) of the device with a single emitter unit. This might be one of the highest efficiencies of OLEDs applying ultrathin emitters without light extraction. Moreover, with the proposed structure, the color gamut of the displays can be effectively increased from 76% to 82% NTSC if the same red and blue emissions as those in the NTSC are applied. A novel form of harmonious fusion among interface exciplex, UEML, and tandem structure is successfully realized, which sheds light on further development of ideal OLED structure with high efficiency, simplified fabrication, low power consumption, low cost, and improved color gamut, simultaneously.

Physical characteristics modification of a SiGe-HBT semiconductor device for performance improvement in a terahertz detecting system

Science.gov (United States)

Ghodsi, Hamed; Kaatuzian, Hassan

2015-05-01

In order to improve the performance of a pre-designed direct conversion terahertz detector which is implemented in a 0.25 μm-SiGe-BiCMOS process, we propose some slight modifications in the bipolar section of the SiGe device physical design. Comparison of our new proposed device and the previously reported device is done by SILVACO TCAD software simulation and we have used previous experimentally reported data to confirm our software simulations. Our proposed modifications in device structural design show a present device responsivity improvement of about 10% from 1 to 1.1 A/W while the bandwidth improvement is about 218 GHz. The minimum noise equivalent power at detector output is increased by about 14.3% and finally power consumption per pixel at the maximum responsivity is decreased by about 5%.

Improving radiation use efficiency in greenhouse production systems

OpenAIRE

Li, Tao

2015-01-01

SUMMARY A large increase in agricultural production is needed to feed the increasing world population with their increasing demand per capita. However, growing competition for arable land, water, energy, and the degradation of the environment impose challenges to improve crop production. Hence agricultural production efficiency needs to increase. Greenhouses provide the possibility to create optimal growth conditions for crops, thereby improving production and product quality. Light is the dr...

Rotary powered device for bone marrow aspiration and biopsy yields excellent specimens quickly and efficiently.

Science.gov (United States)

Swords, Ronan T; Kelly, Kevin R; Cohen, Stephen C; Miller, Larry J; Philbeck, Thomas E; Hacker, Sander O; Spadaccini, Cathy J; Giles, Francis J; Brenner, Andrew J

2010-06-01

Recently, a new FDA-cleared battery powered bone marrow biopsy system was developed to allow operators access to the bone marrow space quickly and efficiently. A pre-clinical evaluation of the device (OnControl, Vidacare Corporation, San Antonio, TX, USA) on anesthetized pigs was conducted, in addition to a clinical evaluation in hematology clinic patients requiring a bone marrow biopsy. Twenty-six samples were collected from the swine model. No cellular artifact or thermal damage was reported in any of the samples obtained. For the clinical evaluation of the device, 16 patients were recruited. Mean time from needle contact with skin to needle removal was 38.5 +/- 13.94 seconds. No complications were reported. In this study, the manual and powered samples were equivalent in specimen quality. In the patients evaluated, the device was safe, easy to use and the mean procedural time was significantly faster than previously reported with a manual technique.

Energy efficiency improvement and environment in China

International Nuclear Information System (INIS)

Rouhier, Stephane

2010-01-01

Massive reliance on polluting sources of energy (coal, traditional biomass and oil) has damaged the environment in China over years. Now, China is the world's first carbon dioxide emitter and air pollution represents between 2 and 7 percent of loss of Gross Domestic Product per year, depending on the studies chosen. In order to reduce the level of pollution, one can either enhance the technology in use or reduce the share of polluting fuels in the energy mix. Indeed, current Chinese technologies are far less efficient than those of developed countries and the energy mix is massively composed of polluting sources of energy. So, they both represent huge potential savings. This article enquires the link between diversification, efficiency in the power sector and the per capita emissions and shows that emissions are negatively correlated to a diversification of the energy mix as well as an improvement of power generating technologies. Hence, it justifies the diversification of the energy mix and technology improvement as viable strategies to tackle pollution

A point-based rendering approach for real-time interaction on mobile devices

Institute of Scientific and Technical Information of China (English)

LIANG XiaoHui; ZHAO QinPing; HE ZhiYing; XIE Ke; LIU YuBo

2009-01-01

Mobile device is an Important interactive platform. Due to the limitation of computation, memory, display area and energy, how to realize the efficient and real-time interaction of 3D models based on mobile devices is an important research topic. Considering features of mobile devices, this paper adopts remote rendering mode and point models, and then, proposes a transmission and rendering approach that could interact in real time. First, improved simplification algorithm based on MLS and display resolution of mobile devices is proposed. Then, a hierarchy selection of point models and a QoS transmission control strategy are given based on interest area of operator, interest degree of object in the virtual environment and rendering error. They can save the energy consumption. Finally, the rendering and interaction of point models are completed on mobile devices. The experiments show that our method is efficient.

Improvement of Engineering Work Efficiency through System Integration

International Nuclear Information System (INIS)

Lee, Sangdae; Jo, Sunghan; Hyun, Jinwoo

2016-01-01

This paper presents the concept of developing an integrated engineering system for ER to improve efficiency and utilization of engineering system. Each process including computer system and database was introduced separately by each department at that different time. Each engineering process has a close relation with other engineering processes. The introduction of processes in a different time has caused the several problems such as lack of interrelationship between engineering processes, lack of integration fleet-wide statistical data, lack of the function of data comparison among plants and increase of access time by different access location on internet. These problems have caused inefficiency of engineering system utilization to get proper information and degraded engineering system utilization. KHNP has introduced and conducted advanced engineering processes to maintain equipment effectively in a highly reliable condition since 2000s. But engineering systems for process implementation have been developed in each department at a different time. This has caused the problems of process inefficiency and data discordance. Integrated Engineering System(IES) to integrate dispersed engineering processes will improve work efficiency and utilization of engineering system because integration system would enable engineer to get total engineering information easily and do engineering work efficiently

Improvement of Engineering Work Efficiency through System Integration

Energy Technology Data Exchange (ETDEWEB)

Lee, Sangdae; Jo, Sunghan; Hyun, Jinwoo [KHNP CRI, Daejeon (Korea, Republic of)

2016-10-15

This paper presents the concept of developing an integrated engineering system for ER to improve efficiency and utilization of engineering system. Each process including computer system and database was introduced separately by each department at that different time. Each engineering process has a close relation with other engineering processes. The introduction of processes in a different time has caused the several problems such as lack of interrelationship between engineering processes, lack of integration fleet-wide statistical data, lack of the function of data comparison among plants and increase of access time by different access location on internet. These problems have caused inefficiency of engineering system utilization to get proper information and degraded engineering system utilization. KHNP has introduced and conducted advanced engineering processes to maintain equipment effectively in a highly reliable condition since 2000s. But engineering systems for process implementation have been developed in each department at a different time. This has caused the problems of process inefficiency and data discordance. Integrated Engineering System(IES) to integrate dispersed engineering processes will improve work efficiency and utilization of engineering system because integration system would enable engineer to get total engineering information easily and do engineering work efficiently.

Controllable Spatial Configuration on Cathode Interface for Enhanced Photovoltaic Performance and Device Stability.

Science.gov (United States)

Li, Jiangsheng; Duan, Chenghao; Wang, Ning; Zhao, Chengjie; Han, Wei; Jiang, Li; Wang, Jizheng; Zhao, Yingjie; Huang, Changshui; Jiu, Tonggang

2018-05-08

The molecular structure of cathode interface modification materials can affect the surface morphology of the active layer and key electron transfer processes occurring at the interface of polymer solar cells in inverted structures mostly due to the change of molecular configuration. To investigate the effects of spatial configuration of the cathode interfacial modification layer on polymer solar cells device performances, we introduced two novel organic ionic salts (linear NS2 and three-dimensional (3D) NS4) combined with the ZnO film to fabricate highly efficient inverted solar cells. Both organic ionic salts successfully decreased the surface traps of the ZnO film and made its work function more compatible. Especially NS4 in three-dimensional configuration increased the electron mobility and extraction efficiency of the interfacial film, leading to a significant improvement of device performance. Power conversion efficiency (PCE) of 10.09% based on NS4 was achieved. Moreover, 3D interfacial modification could retain about 92% of its initial PCE over 160 days. It is proposed that 3D interfacial modification retards the element penetration-induced degradation without impeding the electron transfer from the active layer to the ZnO film, which significantly improves device stability. This indicates that inserting three-dimensional organic ionic salt is an efficient strategy to enhance device performance.

Surface modification with MK-2 organic dye in a ZnO/P3HT hybrid solar cell: Impact on device performance

Directory of Open Access Journals (Sweden)

Yu Jin Kim

2014-07-01

Full Text Available The photovoltaic performance of a hybrid ZnO/P3HT heterojunction was improved by modifying the device surface with the MK-2 dye. This organic dye enhanced the compatibility between the polymer and the metal oxide, increased the exciton separation efficiency, and improved the molecular ordering in the charge transport network. The resulting device displayed a substantial enhancement in the photocurrent, open circuit voltage, and fill factor, leading to a 12-fold increase in the power conversion efficiency relative to the unmodified device, from 0.13% to 1.53%.

Highly efficient blue organic light emitting device using indium-free transparent anode Ga:ZnO with scalability for large area coating

International Nuclear Information System (INIS)

Wang Liang; Matson, Dean W.; Polikarpov, Evgueni; Swensen, James S.; Bonham, Charles C.; Cosimbescu, Lelia; Gaspar, Daniel J.; Padmaperuma, Asanga B.; Berry, Joseph J.; Ginley, David S.

2010-01-01

Organic light emitting devices have been achieved with an indium-free transparent anode, Ga doped ZnO (GZO). A large area coating technique was used (RF magnetron sputtering) to deposit the GZO films onto glass. The respective organic light emitting devices exhibited an operational voltage of 3.7 V, an external quantum efficiency of 17%, and a power efficiency of 39 lm/W at a current density of 1 mA/cm 2 . These parameters are well within acceptable standards for blue OLEDs to generate a white light with high enough brightness for general lighting applications. It is expected that high-efficiency, long-lifetime, large area, and cost-effective white OLEDs can be made with these indium-free anode materials.

Evaluating imaging devices

International Nuclear Information System (INIS)

Rollo, F.D.

1977-01-01

The performance of any imaging device depends on two principal factors inherent to the device, namely, plane sensitivity and spatial resolution. These factors may be defined as follows: plane sensitivity is the counts per second recorded by the imaging device for each disintegration per second per square centimeter occurring within a plane sheet of radioactivity. Spatial resolution may be defined as the fidelity with which the imaging device reproduces the activity distribution of an object in the image plane. In all imaging devices, a trade-off exists between these two parameters; that is, as sensitivity improves, spatial resolution is degraded, and vice versa. Therefore, to fully evaluate an imaging system a technique should be selected that measures both parameters and reflects the trade-off between the two. In addition, the method should approximate the clinical problem, namely, the detection of a focal lesion within an activity distribution. Several methods have been described to evaluate nuclear imaging devices. The more common techniques include the use of organ phantoms, bar phantoms, line-spread functions, modulation transfer functions, contrast efficiency functions, and performance index functions. Each of these techniques is briefly described in this chapter, and their advantages and disadvantages are discussed. In addition, a phantom that can be used to simply and completely measure overall imaging system performance is described

High efficiency graphene coated copper based thermocells connected in series

Science.gov (United States)

Sindhuja, Mani; Indubala, Emayavaramban; Sudha, Venkatachalam; Harinipriya, Seshadri

2018-04-01

Conversion of low-grade waste heat into electricity had been studied employing single thermocell or flowcells so far. Graphene coated copper electrodes based thermocells connected in series displayed relatively high efficiency of thermal energy harvesting. The maximum power output of 49.2W/m2 for normalized cross sectional electrode area is obtained at 60ºC of inter electrode temperature difference. The relative carnot efficiency of 20.2% is obtained from the device. The importance of reducing the mass transfer and ion transfer resistance to improve the efficiency of the device is demonstrated. Degradation studies confirmed mild oxidation of copper foil due to corrosion caused by the electrolyte.

Improvement of SET variability in TaO x based resistive RAM devices

Science.gov (United States)

Schönhals, Alexander; Waser, Rainer; Wouters, Dirk J.

2017-11-01

Improvement or at least control of variability is one of the key challenges for Redox based resistive switching memory technology. In this paper, we investigate the impact of a serial resistor as a voltage divider on the SET variability in Pt/Ta2O5/Ta/Pt nano crossbar devices. A partial RESET in a competing complementary switching (CS) mode is identified as a possible failure mechanism of bipolar switching SET in our devices. Due to a voltage divider effect, serial resistance value shows unequal impact on switching voltages of both modes which allows for a selective suppression of the CS mode. The impact of voltage divider on SET variability is demonstrated. A combination of appropriate write voltage and serial resistance allows for a significant improvement of the SET variability.

Effects of Iodine Doping on Carrier Behavior at the Interface of Perovskite Crystals: Efficiency and Stability

Directory of Open Access Journals (Sweden)

Guilin Liu

2018-04-01

Full Text Available The interface related to the polycrystalline hybrid perovskite thin film plays an essential role in the resulting device performance. Iodine was employed as an additive to modify the interface between perovskite and spiro-OMeTAD hole transport layer. The oxidation ability of iodine significantly improved the efficiency of charge extraction for perovskite solar cells. It reveals that the Open Circuit Voltage (Voc and Fill Factor (FF of perovskite solar cells were improved substantially due to the dopant, which is mainly attributed to the interfacial improvement. It was found that the best efficiency of the devices was achieved when the dopant of iodine was in equivalent mole concentration with that of spiro-OMeTAD. Moreover, the long-term stability of the corresponding device was investigated.

Efficiency improvement opportunities for personal computer monitors. Implications for market transformation programs

Energy Technology Data Exchange (ETDEWEB)

Park, Won Young; Phadke, Amol; Shah, Nihar [Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

2013-08-15

Displays account for a significant portion of electricity consumed in personal computer (PC) use, and global PC monitor shipments are expected to continue to increase. We assess the market trends in the energy efficiency of PC monitors that are likely to occur without any additional policy intervention and estimate that PC monitor efficiency will likely improve by over 40 % by 2015 with saving potential of 4.5 TWh per year in 2015, compared to today's technology. We discuss various energy-efficiency improvement options and evaluate the cost-effectiveness of three of them, at least one of which improves efficiency by at least 20 % cost effectively beyond the ongoing market trends. We assess the potential for further improving efficiency taking into account the recent development of universal serial bus-powered liquid crystal display monitors and find that the current technology available and deployed in them has the potential to deeply and cost effectively reduce energy consumption by as much as 50 %. We provide insights for policies and programs that can be used to accelerate the adoption of efficient technologies to further capture global energy saving potential from PC monitors which we estimate to be 9.2 TWh per year in 2015.

Contact engineering for efficient charge injection in organic transistors with low-cost metal electrodes

Science.gov (United States)

Panigrahi, D.; Kumar, S.; Dhar, A.

2017-10-01

Controlling charge injection at the metal-semiconductor interface is very crucial for organic electronic devices in general as it can significantly influence the overall device performance. Herein, we report a facile, yet efficient contact modification approach, to enhance the hole injection efficiency through the incorporation of a high vacuum deposited TPD [N,N'-Bis(3-methylphenyl)-N,N'-diphenylbenzidine] interlayer between the electrodes and the active semiconducting layer. The device performance parameters such as mobility and on/off ratio improved significantly after the inclusion of the TPD buffer layer, and more interestingly, the devices with cost effective Ag and Cu electrodes were able to exhibit a superior device performance than the typically used Au source-drain devices. We have also observed that this contact modification technique can be even more effective than commonly used metal oxide interface modifying layers. Our investigations demonstrate the efficacy of the TPD interlayer in effectively reducing the interfacial contact resistance through the modification of pentacene energy levels, which consequently results in the substantial improvement in the device performances.

Study on collection efficiency of fission products by spray: Experimental device and modelling

Energy Technology Data Exchange (ETDEWEB)

Ducret, D.; Roblot, D.; Vendel, J. [Institut de Protection et de Surete Nucleaire, Gif-Sur-Yvette (France); Billarand, Y. [ECCO Pharmacie et Chimie, Neuilly (France)

1997-08-01

Consequences of an hypothetical overheating reactor accident in nuclear power plants can be limited by spraying cold water drops into containment building. The spray reduces the pressure and the temperature levels by condensation of steam and leads to the washout of fission products (aerosols and gaseous iodine). The present study includes a large program devoted to the evaluation of realistic washout rates. An experimental device (named CARAIDAS) was designed and built in order to determine the collection efficiency of aerosols and iodine absorption by drops with representative conditions of post-accident atmosphere. This experimental device is presented in the paper and more particularly: (1) the experimental enclosure in which representative thermodynamic conditions can be achieved, (2) the monosized drops generator, the drops diameter measurement and the drops collector, (3) the cesium iodide aerosols generator and the aerosols measurements. Modelling of steam condensation on drops aerosols collection and iodine absorption are described. First experimental and code results on drops and aerosols behaviour are compared. 8 refs., 18 figs.