WorldWideScience

Sample records for based contact energies

  1. Investigation of contact electrification based broadband energy harvesting mechanism using elastic PDMS microstructures

    International Nuclear Information System (INIS)

    Triboelectric energy harvesting has recently garnered a lot of interest because of its easy fabrication and high power output. Contact electrification depends on the chemical properties of contacting materials. Another important factor in contact electrification mechanism is surfaces’ elastic and topographical characteristics. One of the biggest limitations of resonant mechanism based devices is their narrow operating bandwidth. This paper presents a broadband mechanism which utilizes stiffness induced in the cantilever motion due to contact between two triboelectric surfaces. We have conducted experiments using polydimethylsiloxane (PDMS) micropad patterns to study the effect of micropad array configuration on the performance of triboelectric energy harvesting devices. The maximum power output measured from the device was observed to be 0.69 μW at an acceleration of 1 g. Due to the non-linearity introduced by contact separation mechanism, the bandwidth of the triboelectric energy harvester was observed to be increased by 63% at an acceleration level of 1 g. A hybrid energy harvesting mechanism has also been demonstrated by compounding the triboelectric energy harvester with a piezoelectric bimorph. (paper)

  2. Robust thin-film generator based on segmented contact-electrification for harvesting wind energy.

    Science.gov (United States)

    Meng, Xian Song; Zhu, Guang; Wang, Zhong Lin

    2014-06-11

    Collecting and converting energy from ambient air flow promise to be a viable approach in developing self-powered autonomous electronics. Here, we report an effective and robust triboelectric generator that consists of an undulating thin-film membrane and an array of segmented fine-sized electrode pairs on a single substrate. Sequential processes of contact electrification and electrostatic induction generate alternating flows of free electrons when the membrane interacts with ambient air flow. Based on an optimum rational design, the segmented electrodes play an essential role in boosting the output current, leading to an enhancement of over 500% compared to the structure without the segmentation. The thin-film based generator can simultaneously and continuously light up tens of commercial light-emitting diodes. Moreover, it possesses exceptional durability, providing constant electric output after millions of operation cycles. This work offers a truly practical solution that opens the avenue to take advantage of wind energy by using the triboelectric effect. PMID:24824071

  3. Evaluation of the energy barrier for failure of Au atomic contact based on temperature dependent current-voltage characteristics.

    Science.gov (United States)

    Aiba, Akira; Kaneko, Satoshi; Fujii, Shintaro; Nishino, Tomoaki; Kiguchi, Manabu

    2016-08-01

    We investigated the mechanical stability of single gold atomic contacts at an applied bias voltage of 0-1 V using a nano-fabricated mechanically controllable break junction technique at 300-400 K under ambient conditions. The single atomic contact shows the quantized conductance (G0 = 2e(2)/h) and can carry considerably large current, which results in the current-induced failure of the contact. The contact failure behaviour under the applied bias conditions was studied by statistical analysis of the current-voltage (I-V) curves of the single Au contacts. We demonstrated that, at the elevated temperature of 300-400 K, the current-induced local heating effect is negligibly small and current-induced forces in the contact are responsible for the observed failure of the single gold contacts under the high bias voltage conditions (>0.4 V). Furthermore, based on the temperature dependence of the contact failure behaviour in the I-V curves, the energy barrier of the contact-failure was evaluated to be ca. 0.1 V. PMID:27427285

  4. Freestanding triboelectric-layer-based nanogenerators for harvesting energy from a moving object or human motion in contact and non-contact modes.

    Science.gov (United States)

    Wang, Sihong; Xie, Yannan; Niu, Simiao; Lin, Long; Wang, Zhong Lin

    2014-05-01

    For versatile mechanical energy harvesting from arbitrary moving objects such as humans, a new mode of triboelectric nanogenerator is developed based on the sliding of a freestanding triboelectric-layer between two stationary electrodes on the same plane. With two electrodes alternatively approached by the tribo-charges on the sliding layer, electricity is effectively generated due to electrostatic induction. A unique feature of this nanogenerator is that it can operate in non-contact sliding mode, which greatly increases the lifetime and the efficiency of such devices. PMID:24449058

  5. The hybrid energy storages based on batteries and ultracapacitors for contact microwelding

    Directory of Open Access Journals (Sweden)

    Bondarenko Yu. V.

    2014-08-01

    Full Text Available Micro resistance welding is an effective way to reliably join small-scale parts. It is widely used in electronics and instrument-making. The important particularities of micro resistance welding are pulse character of energy consumption, non-linear load and special form of current pulses. So, these particularities of welding process cause negative influence on the mains. One of the known ways to avoid it is to use autonomous power supplies for micro resistance welding machines. The important task for building autonomous power supplies is to choose effective energy storages, which have high capacity and small internal resistance, and which are capable to be charged and deliver energy to load very quickly. The solution of this task is seen in using hybrid energy storages, which include accumulators and ultracapacitors. The accumulators are able to provide high energy capacitance and the ultracapacitors are able to provide fast energy delivery. The possibility of application of hybrid energy storages, based on accumulator batteries and ultracapacitors, in micro resistance welding machines is confirmed with computer simulation. Two variants of hybrid energy storages are proposed. These hybrid energy storages have high power and dynamic characteristics, which are sufficient to generate current pulses for welding according to necessary settings.

  6. Mechanism of contact angle saturation and an energy-based model for electrowetting

    Science.gov (United States)

    Rui, Zhao; Zhong-Cheng, Liang

    2016-06-01

    Electrowetting, as a well-known approach to increasing droplet wettability on a solid surface by electrical bias, has broad applications. However, it is limited by contact angle saturation at large voltage. Although several debated hypotheses have been proposed to describe it, the physical origin of contact angle saturation still remains obscure. In this work, the physical factors responsible for the onset of contact angle saturation are explored, and the correlated theoretical models are established to characterize electrowetting behavior. Combination of the proper 3-phase system employed succeeds in dropping the saturating contact angle below 25°, and validates that the contact angle saturation is not a result of device-related imperfection. Project supported by the Fund from the Research Center of Optical Communications Engineering & Technology, Jiangsu Province, China (Grant No. ZSF0402).

  7. Energy Academic Group Faculty Contacts

    OpenAIRE

    2013-01-01

    NPS Defense Energy Programs are interdisciplinary, shared by organizational units throughout the campus. A wide range of NPS faculty are affiliated with the Energy program, actively participating in Energy graduate education, Energy executive education and Energy research.

  8. Contact term, its holographic description in QCD and dark energy

    Science.gov (United States)

    Zhitnitsky, Ariel R.

    2012-08-01

    In this work we study the well-known contact term, which is the key element in resolving the so-called U(1)A problem in QCD. We study this term using the dual holographic description. We argue that in the dual picture the contact term is saturated by the D2-branes which can be interpreted as the tunneling events in Minkowski space-time. We quote a number of direct lattice results supporting this identification. We also argue that the contact term receives a Casimir-like correction ˜(ΛQCDR)-1 rather than the naively expected exp⁡(-ΛQCDR) when the Minkowski space-time R3,1 is replaced by a large but finite manifold with a size R. Such a behavior is consistent with other quantum field theory (QFT)-based computations when powerlike corrections are due to nontrivial properties of topological sectors of the theory. In holographic description, such a behavior is due to a massless Ramond-Ramond (RR) field living in the bulk of multidimensional space when powerlike corrections is a natural outcome of a massless RR field. In many respects, the phenomenon is similar to the Aharonov-Casher effect when the “modular electric field” can penetrate into a superconductor where the electric field is exponentially screened. The role of “modular operator” from the Aharonov-Casher effect is played by a large-gauge transformation operator T in four-dimensional QCD, resulting in the transparency of the system to topologically nontrivial pure gauge configurations. We discuss some profound consequences of our findings. In particular, we speculate that a slow variation of the contact term in expanding universe might be the main source of the observed dark energy.

  9. Tri-residue contact potential: a new knowledge-based energetic method

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new knowledge-based potential method, the tri-residue contact potential (TRICP), is proposed. This approach resembles the idea of environment-dependent residue contact energy reported by Zhang et al. We statistically study the 3-dimensional structure of proteins and calculate the knowledge-based contact potential of tri-residue clusters. These contact potentials are carefully compared to pairwise contact potentials (PCP). TRICP helps us to systematically examine the impact on the interactions of residue pairs by the third residue. Moreover, TRICP provides us with many clues to identify high frequency characteristic structural units in protein structures.

  10. Flexible textile-based strain sensor induced by contacts

    International Nuclear Information System (INIS)

    In this paper, the contact effects are used as the key sensing element to develop flexible textile-structured strain sensors. The structures of the contact are analyzed theoretically and the contact resistances are investigated experimentally. The electromechanical properties of the textiles are investigated to find the key factors which determine the sensitivity, repeatability, and linearity of the sensor. The sensing mechanism is based on the change of contact resistance induced by the change of the configuration of the textiles. In order to improve the performance of the textile strain sensor, the contact resistance is designed based on the electromechanical properties of the fabric. It can be seen from the results that the performance of the sensor is largely affected by the structure of the contacts, which are determined by the morphology of fiber surface and the structures of the yarn and fabric. (paper)

  11. Force Based Skill Learning for Robot Tasks in Contact Conditions

    Institute of Scientific and Technical Information of China (English)

    王琴; 梅志千; 张广立; 杨汝清

    2004-01-01

    To acquire human operation skill based on force sense, element contact form (ECF) is proposed to describe contact condition firstly. The skill is modeled as a sequence of discrete ECFs. Since different ECF has different force distribution, a support vector machine classifier is built to identify the contact conditions according to the force signal. Finally, the robot can obtain the skill from the human demonstration.

  12. Cryotrons based on a simultaneously distributed Josephson contact

    Energy Technology Data Exchange (ETDEWEB)

    Bakhtin, P.A.; Lapir, G.M.; Makhov, V.I.; Samus, A.N.; Semenov, V.K.; Tyablikov, A.V.

    1982-01-01

    The features of the construction of cryotrons based on an evenly distributed Josephson contact are examined. The possibility is demonstrated of producing cryotrons with an assigned form of the controlling characteristic through the spatial isolation of the transport and controlling streams. The theoretical and experimental controlling characteristics of cryotrons based on bridges of variable thickness with connectors of normal metal are cited. The proposed principles of cryotron production are also suitable for other types of Josephson contacts.

  13. Mass spectrometry-based proteomic analyses of contact lens deposition

    OpenAIRE

    Green-Church, Kari B.; Nichols, Jason J

    2008-01-01

    Purpose The purpose of this report is to describe the contact lens deposition proteome associated with two silicone hydrogel contact lenses and care solutions using a mass spectrometric-based approach. Methods This was a randomized, controlled, examiner-masked crossover clinical trial that included 48 participants. Lenses and no-rub care solutions evaluated included galyfilcon A (Acuvue Advance, Vistakon Inc., Jacksonville, FL), lotrafilcon B (O2 Optix, CIBA Vision Inc., Duluth, GA), AQuify (...

  14. Novel vertical silicon photodiodes based on salicided polysilicon trenched contacts

    International Nuclear Information System (INIS)

    The classical concept of silicon photodiodes comprises of a planar design characterized by heavily doped emitters. Such geometry has low collection efficiency of the photons absorbed close to the surface. An alternative, promising, approach is to use a vertical design. Nevertheless, realization of such design is technologically challenged, hence hardly explored. Herein, a novel type of silicon photodiodes, based on salicided polysilicon trenched contacts, is presented. These contacts can be prepared up to 10 μm in depth, without showing any leakage current associated with the increase in the contact area. Consequently, the trenched photodiodes revealed better performance than no-trench photodiodes. A simple two dimensional model was developed, allowing to estimate the conditions under which a vertical design has the potential to have better performance than that of a planar design. At large, the deeper the trench is, the better is the vertical design relative to the planar (up to 10 μm for silicon). The vertical design is more advantageous for materials characterized by short diffusion lengths of the carriers. Salicided polysilicon trenched contacts open new opportunities for the design of solar cells and image sensors. For example, these contacts may passivate high contact area buried contacts, by virtue of the conformity of polysilicon interlayer, thus lowering the via resistance induced recombination enhancement effect

  15. Novel vertical silicon photodiodes based on salicided polysilicon trenched contacts

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, Yelena [Department of Chemical Engineering, Technion, Haifa (Israel); TowerJazz Ltd. Migdal Haemek (Israel); Shauly, Eitan [TowerJazz Ltd. Migdal Haemek (Israel); Paz, Yaron, E-mail: paz@tx.technion.ac.il [Department of Chemical Engineering, Technion, Haifa (Israel)

    2015-12-07

    The classical concept of silicon photodiodes comprises of a planar design characterized by heavily doped emitters. Such geometry has low collection efficiency of the photons absorbed close to the surface. An alternative, promising, approach is to use a vertical design. Nevertheless, realization of such design is technologically challenged, hence hardly explored. Herein, a novel type of silicon photodiodes, based on salicided polysilicon trenched contacts, is presented. These contacts can be prepared up to 10 μm in depth, without showing any leakage current associated with the increase in the contact area. Consequently, the trenched photodiodes revealed better performance than no-trench photodiodes. A simple two dimensional model was developed, allowing to estimate the conditions under which a vertical design has the potential to have better performance than that of a planar design. At large, the deeper the trench is, the better is the vertical design relative to the planar (up to 10 μm for silicon). The vertical design is more advantageous for materials characterized by short diffusion lengths of the carriers. Salicided polysilicon trenched contacts open new opportunities for the design of solar cells and image sensors. For example, these contacts may passivate high contact area buried contacts, by virtue of the conformity of polysilicon interlayer, thus lowering the via resistance induced recombination enhancement effect.

  16. Contact Term, its Holographic Description in QCD and Dark Energy

    CERN Document Server

    Zhitnitsky, Ariel R

    2011-01-01

    In this work we study the well known contact term, which is the key element in resolving the so-called $U(1)_A$ problem in QCD. We study this term using the dual Holographic Description. We argue that in the dual picture the contact term is saturated by the D2 branes which can be interpreted as the tunnelling events in Minkowski space-time. We present a number of direct lattice results supporting this identification. We also argue that the contact term receives a Casimir -like correction $\\sim (\\Lqcd R)^{-1}$ rather than naively expected $\\exp(-\\Lqcd R)$ when the Minkowski space-time ${\\cal R}_{3,1}$ is replaced by a large but finite manifold with a size $R$. Such a behaviour is consistent with other QFT-based computations when power like corrections are due to nontrivial properties of topological sectors of the theory. In holographic description such a behaviour is due to massless Ramond-Ramond (RR) field living in the bulk of multidimensional space when power like corrections is a natural outcome of massles...

  17. Determination of the Contact Angle Based on the Casimir Effect

    Science.gov (United States)

    Mazuruk, K.; Volz, M. P.

    2015-01-01

    In several crystal growth processed based on capillarity, a melt comes into contact with a crucible wall at an angle defined as the contact angle. For molten metals and semiconductors, this contact angle is dependent upon both the crucible and melt material and typical values fall in the range 80-170deg. However, on a microscopic scale, there does not exist a precise and sharp contact angle but rather the melt and solid surfaces merge smoothly and continuously over a distance of up to several micrometers. Accurate modeling requires a more advanced treatment of this interaction. The interaction between the melt and solid surfaces can be calculated by considering two forces: a short-range repulsive force and a longer range (up to a few micrometers) Casimir force. The Casimir force between the two bodies of complex geometry is calculated using a retarded temperature Green's function (Matsubara type) for the photon in the medium. The governing equations are cast in the form of a set of boundary integral equations which are then solved numerically for the case of molten Ge on SiO2. The shape of the molten surface approaching the flat solid body is determined, and the contact angle is defined as the angle between the two surfaces at the microscopically asymptotic distance of 1-2 micrometers. The formulation of this model and the results of the numerical calculations will be presented and discussed.

  18. Energy. Political contacts at national, state and European level; Energie. Politikkontakte Bund, Land, Europa

    Energy Technology Data Exchange (ETDEWEB)

    Holzapfel, Andreas (ed.)

    2013-04-01

    The manual is in three sections: 1. Parliaments and governments, survey and organization; 2. Biographic section, with 304 biography; 3. Index of names. The first section informs on the organizational structure of parliaments and governments. The subject of energy is discussed three times, i.e. in 'Economics', 'Environment', and 'Research'. For each parliament, the members of the energy policy TCs are listed, followed by names and contact addresses of the senior officials and departments with contact data, both on a national, state, and European scale. The second section contains the biographies of energy policy experts of the German parliament and government, the sixteen land parliaments and governments, and the European Commissions. As the subject of energy is highly interdisciplinary, the authors selected the energy policy committees of the German parliament and state parliaments. The biographies of the committee members are presented in the text.

  19. Total energy expenditure estimated using foot-ground contact pedometry.

    Science.gov (United States)

    Hoyt, Reed W; Buller, Mark J; Santee, William R; Yokota, Miyo; Weyand, Peter G; Delany, James P

    2004-02-01

    Routine walking and running, by increasing daily total energy expenditure (TEE), can play a significant role in reducing the likelihood of obesity. The objective of this field study was to compare TEE estimated using foot-ground contact time (Tc)-pedometry (TEE(PEDO)) with that measured by the criterion doubly labeled water (DLW) method. Eight male U.S. Marine test volunteers [27 +/- 4 years of age (mean +/- SD); weight = 83.2 +/- 10.7 kg; height = 182.2 +/- 4.5 cm; body fat = 17.0 +/- 2.9%] engaged in a field training exercise were studied over 2 days. TEE(PEDO) was defined as (calculated resting energy expenditure + estimated thermic effect of food + metabolic cost of physical activity), where physical activity was estimated by Tc-pedometry. Tc-pedometry was used to differentiate inactivity, activity other than exercise (i.e., non-exercise activity thermogenesis, or NEAT), and the metabolic cost of locomotion (M(LOCO)), where M(LOCO) was derived from total weight (body weight + load weight) and accelerometric measurements of Tc. TEE(PEDO) data were compared with TEEs measured by the DLW (2H2(18)O) method (TEE(DLW)): TEE(DLW) = 15.27 +/- 1.65 MJ/day and TEE(PEDO) = 15.29 +/- 0.83 MJ/day. Mean bias (i.e., TEE(PEDO) - TEE(DLW)) was 0.02 MJ, and mean error (SD of individual differences between TEE(PEDO) and TEE(DLW)) was 1.83 MJ. The Tc-pedometry method provided a valid estimate of the average TEE of a small group of physically active subjects where walking was the dominant activity. PMID:15000774

  20. Total energy expenditure estimated using foot-ground contact pedometry.

    Science.gov (United States)

    Hoyt, Reed W; Buller, Mark J; Santee, William R; Yokota, Miyo; Weyand, Peter G; Delany, James P

    2004-02-01

    Routine walking and running, by increasing daily total energy expenditure (TEE), can play a significant role in reducing the likelihood of obesity. The objective of this field study was to compare TEE estimated using foot-ground contact time (Tc)-pedometry (TEE(PEDO)) with that measured by the criterion doubly labeled water (DLW) method. Eight male U.S. Marine test volunteers [27 +/- 4 years of age (mean +/- SD); weight = 83.2 +/- 10.7 kg; height = 182.2 +/- 4.5 cm; body fat = 17.0 +/- 2.9%] engaged in a field training exercise were studied over 2 days. TEE(PEDO) was defined as (calculated resting energy expenditure + estimated thermic effect of food + metabolic cost of physical activity), where physical activity was estimated by Tc-pedometry. Tc-pedometry was used to differentiate inactivity, activity other than exercise (i.e., non-exercise activity thermogenesis, or NEAT), and the metabolic cost of locomotion (M(LOCO)), where M(LOCO) was derived from total weight (body weight + load weight) and accelerometric measurements of Tc. TEE(PEDO) data were compared with TEEs measured by the DLW (2H2(18)O) method (TEE(DLW)): TEE(DLW) = 15.27 +/- 1.65 MJ/day and TEE(PEDO) = 15.29 +/- 0.83 MJ/day. Mean bias (i.e., TEE(PEDO) - TEE(DLW)) was 0.02 MJ, and mean error (SD of individual differences between TEE(PEDO) and TEE(DLW)) was 1.83 MJ. The Tc-pedometry method provided a valid estimate of the average TEE of a small group of physically active subjects where walking was the dominant activity.

  1. Contact-based social contagion in multiplex networks

    Science.gov (United States)

    Cozzo, Emanuele; Baños, Raquel A.; Meloni, Sandro; Moreno, Yamir

    2013-11-01

    We develop a theoretical framework for the study of epidemiclike social contagion in large scale social systems. We consider the most general setting in which different communication platforms or categories form multiplex networks. Specifically, we propose a contact-based information spreading model, and show that the critical point of the multiplex system associated with the active phase is determined by the layer whose contact probability matrix has the largest eigenvalue. The framework is applied to a number of different situations, including a real multiplex system. Finally, we also show that when the system through which information is disseminating is inherently multiplex, working with the graph that results from the aggregation of the different layers is inaccurate.

  2. Contact-based Social Contagion in Multiplex Networks

    CERN Document Server

    Cozzo, E; Meloni, S; Moreno, Y

    2013-01-01

    We develop a theoretical framework for the study of epidemic-like social contagion in large scale social systems. We consider the most general setting in which different communication platforms or categories form multiplex networks. Specifically, we propose a contact-based information spreading model, and show that the critical point of the multiplex system associated to the active phase is determined by the layer whose contact probability matrix has the largest eigenvalue. The framework is applied to a number of different situations, including a real multiplex system. Finally, we also show that when the system through which information is disseminating is inherently multiplex, working with the graph that results from the aggregation of the different layers is flawed.

  3. Simulation Study of AC Contactor Dynamic Contacts Contact Pressure Based on ADAMS

    Directory of Open Access Journals (Sweden)

    Gu Yungao

    2015-01-01

    Full Text Available A multi-body dynamics simulation model of CJ20-25 AC contactor was established with Pro/E(Pro/Engineerin this paper. A coupling simulation with machine, electric, magnetic on the contactor has been achieved in this model. Dynamic parameters which were called use the secondary development technology of ADAMS. The dynamic contact pressure signal of an AC contactor was obtained with ADAMS’s own simultaneous solution such as electromagnetic suction, kinematics and dynamics equations. The simulation results and actual measurement of contactor contact pressure signals are very similar. However, the complexity of the measured contacts vibration is greater than the simulation results because the actual working condition is more complex. This result provides a theoretical foundation to the dynamic contacts contact pressure test.

  4. Non-contact Laser-based Human Respiration Rate Measurement

    Science.gov (United States)

    Scalise, L.; Marchionni, P.; Ercoli, I.

    2011-08-01

    At present the majority of the instrumentation, used in clinical environments, to measure human respiration rate are based on invasive and contact devices. The gold standard instrument is considered the spirometer which is largely used; it needs a direct contact and requires a collaboration by the patient. Laser Doppler Vibrometer (LDVi) is an optical, non-contact measurement system for the assessment of a surface velocity and displacement. LDVi has already been used for the measurement of the cardiac activity and for the measurement of the chest-wall displacements. The aims of this work are to select the best measurement point on the thoracic surface for LDVi monitoring of the respiration rate (RR) and to compare measured data with the RR valued provided by the spirometer. The measurement system is composed by a LDV system and a data acquisition board installed on a PC. Tests were made on 10 different point of the thorax for each patient. Patients population was composed by 33 subjects (17 male and 16 female). The optimal measurement point was chosen considering the maximum peak-to-peak value of the displacement measured by LDV. Before extracting RR we have used a special wavelet decomposition for better selection of the expiration peaks. A standard spirometer was used for the validation of the data. From tests it results that the optimal measurement point, namely is located on the inferior part of the thoracic region (left, front side). From our tests we have obtained a close correlation between the RR values measured by the spirometer and those measured by the proposed method: a difference of 14±211 ms on the RR value is reported for the entire population of 33 subjects. Our method allows a no-contact measurement of lungs activity (respiration period), reducing the electric and biological risks. Moreover it allows to measure in critical environment like in RMN or in burned skin where is difficult or impossible to apply electrodes.

  5. Screening of contact absorption by distant energy quenching

    International Nuclear Information System (INIS)

    Graphical abstract: Sequential appearance of the products of contact and distant excitation quenching executing by electron transfer at different quencher concentrations. - Abstract: The interference between the distant and contact excitation quenching in liquid solutions is considered as well as the kinetics of accumulation and dissipation of their products: excited complexes and ion pairs. The contact one starting first is interrupted by a distant one developed later. In highly viscous solvents the distant reaction completely screens the contact one. This fact first demonstrated here within Markovian encounter theory is then essentially extended with the non-Markovian Unified Theory (UT). The latter allows to specify the yields of all the products and their viscosity and concentration dependencies as well as the kinetics of sequential products accumulation and dissipation.

  6. Surface energy of preservative-treated southern yellow pine (Pinus spp.) by contact angle measurement

    Institute of Scientific and Technical Information of China (English)

    CAO Jinzhen; Pascal D.Kamdem

    2007-01-01

    In this study,the contact angles of four different reference liquids (including distilled water,diiodomethane,formadide and glycerol) formed on the surfaces of wood,treated with chromated copper arsenate (CCA) and two other emerging copper-based water-borne systems (commercial names:NW and NS) were measured with sessile drop method.Based on the contact angle data,the surface energy was obtained from the acid-base approach.The total surface energy consisted of Lifshiz-van der Waals parameter and acid-base parameter.Results showed that the NW and CCA treatments made the wood surface more hydrophobic while the NS treatment had the reverse effect on the wood surface mainly owing to the increased penetration of earlywood.By using three liquids,diiodomethane,formamide and distilled water,the total surface energy obtained for untreated earlywood,untreated latewood, CCA-treated earlywood,CCA-treated latewood,NW-treated earlywood,NW-treated latewood,NS-treated earlywood and NS-treated latewood were 43.1,44.5,43.4,45.1,49.4,40.6,46.0 and 40.9 mJ/m2,respectively.The surface energy of CCA-treated wood was almost the same as untreated wood.After NW and NS treatments,the surface energy of both earlywood and latewood changed a little.However,the change was not so obvious as to draw any further conclusion concerning the influence of NW and NS treatments on the surface energy of wood.

  7. Contact Region Estimation Based on a Vision-Based Tactile Sensor Using a Deformable Touchpad

    Directory of Open Access Journals (Sweden)

    Yuji Ito

    2014-03-01

    Full Text Available A new method is proposed to estimate the contact region between a sensor and an object using a deformable tactile sensor. The sensor consists of a charge-coupled device (CCD camera, light-emitting diode (LED lights and a deformable touchpad. The sensor can obtain a variety of tactile information, such as the contact region, multi-axis contact force, slippage, shape, position and orientation of an object in contact with the touchpad. The proposed method is based on the movements of dots printed on the surface of the touchpad and classifies the contact state of dots into three types—A non-contacting dot, a sticking dot and a slipping dot. Considering the movements of the dots with noise and errors, equations are formulated to discriminate between the contacting dots and the non-contacting dots. A set of the contacting dots discriminated by the formulated equations can construct the contact region. Next, a method is developed to detect the dots in images of the surface of the touchpad captured by the CCD camera. A method to assign numbers to dots for calculating the displacements of the dots is also proposed. Finally, the proposed methods are validated by experimental results.

  8. Probing contact interactions at high energy lepton colliders

    International Nuclear Information System (INIS)

    Fermion compositeness and other new physics can be signaled by the presence of a strong four-fermion contact interaction. Here the authors present a study of ell ell qq and ell ell ell 'ell ' contact interactions using the reactions: ell +ell - → ell '+ ell '-, b anti b, c anti c at future e+e- linear colliders with √s = 0.5--5 TeV and μ+μ- colliders with √s = 0.5, 4 TeV. They find that very large compositeness scales can be probed at these machines and that the use of polarized beams can unravel their underlying helicity structure

  9. Probing contact interactions at high energy lepton colliders

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, K. [Univ. of Texas, Austin, TX (United States); Godfrey, S. [Carleton Univ., Ottawa, Ontario (Canada). Ottawa Carleton Inst. for Physics; Hewett, J.A. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1996-12-01

    Fermion compositeness and other new physics can be signaled by the presence of a strong four-fermion contact interaction. Here the authors present a study of {ell}{ell}qq and {ell}{ell}{ell}{prime}{ell}{prime} contact interactions using the reactions: {ell}{sup +}{ell}{sup {minus}} {r_arrow} {ell}{prime}{sup +} {ell}{prime}{sup {minus}}, b{anti b}, c{anti c} at future e{sup +}e{sup {minus}} linear colliders with {radical}s = 0.5--5 TeV and {mu}{sup +}{mu}{sup {minus}} colliders with {radical}s = 0.5, 4 TeV. They find that very large compositeness scales can be probed at these machines and that the use of polarized beams can unravel their underlying helicity structure.

  10. Energy transfer, volumetric expansion, and removal of oral biofilms by non-contact brushing

    NARCIS (Netherlands)

    Busscher, H. J.; Jager, D.; Finger, G.; Schaefer, N.; van der Mei, H. C.

    2010-01-01

    Non-contact removal of oral biofilms offers advantages beyond the reach of bristles, but it is unknown how energy transfer for removal from brush-to-biofilm occurs. In the present study we evaluated non-contact, oral biofilm removal by oscillating-rotating and sonic toothbrushes, and their acoustic

  11. Electrode contact configuration and energy consumption in spinal cord stimulation

    NARCIS (Netherlands)

    Vos, de Cecile C.; Hilgerink, Marjolein P.; Buschman, Hendrik P.J.; Holsheimer, Jan

    2009-01-01

    Objective: To test the hypothesis that in spinal cord stimulation, in contrast to an increase of the number of anodes which reduces energy consumption per pulse, an increase of the number of cathodes raises the energy per pulse. Methods: Patients with an Itrel 3 pulse generator and a Pisces Quad qu

  12. Experimental determination of the thermal contact conductance between two solid surfaces by the energy pulse technique

    International Nuclear Information System (INIS)

    An experimental procedure for the determination of the thermal contact conductance between two solid surfaces as a function of the contact pressure and the energy of the laser radiation has been developed using the laser pulse method. A rubi laser with variable energy levels was employed as a radiating pulse energy source. The laser beam was allowed to impinge perpendicularly on the front face of a electrolytic iron 734. The temperature fluctuations resulting on the back surface of the sample was detected by a thermocouple, which Is coupled to a PDP-11/45 Computer 32 Kbytes of memory, through a Analog-Digital Converter. A theoretical function, derived exclusively for the problem mentioned in this work, was adjusted by a method of least square fitting of experimental results. This adjustment yielded the value of a parameter related to the contact conductance between two surfaces. The experimental error obtained for the thermal contact conductance was +- 4.9%. (author)

  13. Epidemic Spreading in Contact Networks Based on Exposure Level

    Institute of Scientific and Technical Information of China (English)

    DUAN Wen-Qi; CHEN Zhong; LIU Zeng-Rong

    2006-01-01

    @@ Most epidemic models for the spread of diseases in contact networks take the assumption of the infected probability of a susceptible agent dependent on its absolute number of infectious neighbours. We introduce a new epidemic model in which the infected probability of a susceptible agent in contact networks depends not on its degree but on its exposure level. We find that effective average infection rate (λ) (i.e., the average number of infections produced by a single contact between infected individuals and susceptible individuals) has an epidemic threshold (λ)c = 1, which is related to recovery rate, epidemic mechanisms and topology of contact network. Furthermore,we show the dominating importance of epidemic mechanisms in determining epidemic patterns and discussed the implications of our model for infection control policy.

  14. Rolling contact fatigue testing of peek based composites

    Directory of Open Access Journals (Sweden)

    Petrogalli C.

    2010-06-01

    Full Text Available Rolling contact fatigue phenomenon was investigated on unfilled PEEK and on three different PEEK composites: 10% carbon micro-fiber, graphite and PTFE filled matrix, 30% carbon micro-fiber filled matrix, 30% glass micro-fiber filled matrix. For this aim, roller-shaped specimens were machined from extruded bars of these materials and subjected to rolling contact tests at different contact pressure levels by means of a four roller machine. Contact pressure-life diagrams and wear rates were so obtained and compared, highlighting a relationship with monotonic and hardness materials properties. Microscopic observations of contact surfaces and transversal section of the specimens also allowed observing the damage mechanisms occurred in the materials tested and the effects of the filler. In particular way, deep radial cracks appeared on unfilled PEEK, while spalling and delamination phenomena where found on composites. Diffuse microcracks were found at the filler-matrix interface of the composites specimens, confirming that the fatigue life of these materials is essentially determined by the crack propagation phase, also under rolling contact loading.

  15. Development of a finite volume contact solver based on the penalty method

    OpenAIRE

    Cardiff, Philip; Karac, Aleksandar; Ivankovic, Alojz

    2012-01-01

    This paper describes the development and application of a frictionless contact stress solver based on the cell-centred finite volume method. The contact methodology, implemented in the open-source software OpenFOAM, is derived from the penalty method commonly used in finite element contact algorithms. The solver is verified on two benchmark tests using the available Hertzian analytical solutions.

  16. Contacting mode operation of work function energy harvester

    Science.gov (United States)

    Varpula, A.; Laakso, S. J.; Havia, T.; Kyynäräinen, J.; Prunnila, M.

    2014-11-01

    The work function energy harvester (WFEH) is a variable capacitance vibration energy harvester where the charging of the capacitor electrodes is driven by the work function difference of the electrode materials. In this work, we investigate operation modes of the WFEH by utilizing a macroscopic parallel plate capacitor with Cu and Al electrodes and varying plate distance. We show that by charging the electrodes of the WFEH by letting the electrode plates touch during the operation a significant output power enhancement can be achieved in comparison to the case where the electrodes are charged and discharged only through a load resistor.

  17. Contact-based ligand-clustering approach for the identification of active compounds in virtual screening

    Directory of Open Access Journals (Sweden)

    Mantsyzov AB

    2012-09-01

    Full Text Available Alexey B Mantsyzov,1 Guillaume Bouvier,2 Nathalie Evrard-Todeschi,1 Gildas Bertho11Université Paris Descartes, Sorbonne, Paris, France; 2Institut Pasteur, Paris, FranceAbstract: Evaluation of docking results is one of the most important problems for virtual screening and in silico drug design. Modern approaches for the identification of active compounds in a large data set of docked molecules use energy scoring functions. One of the general and most significant limitations of these methods relates to inaccurate binding energy estimation, which results in false scoring of docked compounds. Automatic analysis of poses using self-organizing maps (AuPosSOM represents an alternative approach for the evaluation of docking results based on the clustering of compounds by the similarity of their contacts with the receptor. A scoring function was developed for the identification of the active compounds in the AuPosSOM clustered dataset. In addition, the AuPosSOM efficiency for the clustering of compounds and the identification of key contacts considered as important for its activity, were also improved. Benchmark tests for several targets revealed that together with the developed scoring function, AuPosSOM represents a good alternative to the energy-based scoring functions for the evaluation of docking results.Keywords: scoring, docking, virtual screening, CAR, AuPosSOM

  18. Ballistic low-temperature Josephson-contacts based on high mobility two-dimensional electron gases

    International Nuclear Information System (INIS)

    During this thesis ballistic low-temperature Josephson-contacts based on niobium-two-dimensional electron gas (2DEG)-niobium structures were designed and fabricated. In order to analyse the influence of the sample preparation on the electronic properties of the niobium-semiconductor interface, IV-curves of single interface junctions were measured. We described the results in terms of an extension of the model by Blonder, Tinkham and Klapwijk (BTK). The Josephson-contacts based on an AlGaSb/InAs-heterostructure showed a supercurrent, which was tunable by an additional current injected via an ohmic contact into the 2DEG. The energy dependence of the suppression of a supercurrent by the injected carriers was measured in a four-terminal configuration. By comparing this result with an effective temperature approach a thermalization of the injected carriers could be excluded. In a three-terminal configuration the supercurrent was switched off locally, which was proven by simulating the measured Fraunhofer-patterns. The niobium-InGaAs/InP-niobium samples which also showed supercurrents were examined with respect to phase coherent transport at finite bias. The observation of fractional Shapiro-steps gave a strong hint to a deviation of the current-phase relation from the sinusodial shape as expected for ballistic Josephson-contacs. (orig.)

  19. Inferring a district-based hierarchical structure of social contacts from census data.

    Directory of Open Access Journals (Sweden)

    Z Yu

    Full Text Available Researchers have recently paid attention to social contact patterns among individuals due to their useful applications in such areas as epidemic evaluation and control, public health decisions, chronic disease research and social network research. Although some studies have estimated social contact patterns from social networks and surveys, few have considered how to infer the hierarchical structure of social contacts directly from census data. In this paper, we focus on inferring an individual's social contact patterns from detailed census data, and generate various types of social contact patterns such as hierarchical-district-structure-based, cross-district and age-district-based patterns. We evaluate newly generated contact patterns derived from detailed 2011 Hong Kong census data by incorporating them into a model and simulation of the 2009 Hong Kong H1N1 epidemic. We then compare the newly generated social contact patterns with the mixing patterns that are often used in the literature, and draw the following conclusions. First, the generation of social contact patterns based on a hierarchical district structure allows for simulations at different district levels. Second, the newly generated social contact patterns reflect individuals social contacts. Third, the newly generated social contact patterns improve the accuracy of the SEIR-based epidemic model.

  20. Ternary Free Energy Lattice Boltzmann Model with Tunable Surface Tensions and Contact Angles

    CERN Document Server

    Semprebon, Ciro; Kusumaatmaja, Halim

    2015-01-01

    We present a new ternary free energy lattice Boltzmann model. The distinguishing feature of our model is that we are able to analytically derive and independently vary all fluid-fluid surface tensions and the solid surface contact angles. We carry out a number of benchmark tests: (i) double emulsions and liquid lenses to validate the surface tensions, (ii) ternary fluids in contact with a square well to compare the contact angles against analytical predictions, and (iii) ternary phase separation to verify that the multicomponent fluid dynamics is accurately captured. Additionally we also describe how the model here presented here can be extended to include an arbitrary number of fluid components.

  1. Flexible carbon-based ohmic contacts for organic transistors

    Science.gov (United States)

    Brandon, Erik (Inventor)

    2007-01-01

    The present invention relates to a system and method of organic thin-film transistors (OTFTs). More specifically, the present invention relates to employing a flexible, conductive particle-polymer composite material for ohmic contacts (i.e. drain and source).

  2. A pairwise residue contact area-based mean force potential for discrimination of native protein structure

    Directory of Open Access Journals (Sweden)

    Pezeshk Hamid

    2010-01-01

    Full Text Available Abstract Background Considering energy function to detect a correct protein fold from incorrect ones is very important for protein structure prediction and protein folding. Knowledge-based mean force potentials are certainly the most popular type of interaction function for protein threading. They are derived from statistical analyses of interacting groups in experimentally determined protein structures. These potentials are developed at the atom or the amino acid level. Based on orientation dependent contact area, a new type of knowledge-based mean force potential has been developed. Results We developed a new approach to calculate a knowledge-based potential of mean-force, using pairwise residue contact area. To test the performance of our approach, we performed it on several decoy sets to measure its ability to discriminate native structure from decoys. This potential has been able to distinguish native structures from the decoys in the most cases. Further, the calculated Z-scores were quite high for all protein datasets. Conclusions This knowledge-based potential of mean force can be used in protein structure prediction, fold recognition, comparative modelling and molecular recognition. The program is available at http://www.bioinf.cs.ipm.ac.ir/softwares/surfield

  3. Direct evaluation of contact injection efficiency into small molecule based transport layers: Influence of extrinsic factors

    Science.gov (United States)

    Abkowitz, M.; Facci, J. S.; Rehm, J.

    1998-03-01

    Studies of interface formation on conventional semiconductor materials are typically carried out under relatively pristine conditions. However, for devices based on the use of electronic polymers there is also compelling interest in exploring the variations in contact behavior that might result under realistic manufacturing conditions like multilayer device assembly based on solution coating technology. Small molecule doped polymers (MDPs) developed principally as large area coatings for electrophotographic use are now finding wider device applications. These polymers are insulators capable of transporting excess injected charge with a unipolar drift mobility which can be tuned over a wide range by varying the concentration of transport active species. Most significant in the present context, MDPs can be rendered trap free by molecular design. These unique characteristics of MDPs make it possible to analyze the relative injection efficiencies of their interfaces with various contacts simply by a direct comparison of current-voltage characteristics with time of flight drift mobility measurements carried out on the same film coatings. In this way, and apart from their intrinsic interest and practical value, MDPs and closely related polymeric media provide the ideal venue for the study of contact phenomena on molecular solids. Almost all the present measurements were carried out by measuring dark hole injection from various preformed metal substrates into the MDP film TPD/polycarbonate. Under these circumstances it was found that while injection efficiency nominally scaled with the estimated interfacial energy step there was significant variance that in some cases could be clearly associated with the specific details of interfacial chemistry. For one exceptional case where Au was evaporated on the free surface of an already cast film a time and temperature dependent contact forming process could be delineated in which the interface systematically evolved from emission

  4. Reducing forward bias voltage of InGaN/GaN-based light emitting diodes by using (In)GaN contact layer

    International Nuclear Information System (INIS)

    The electrical properties of GaN-based light emitting diodes (LEDs) fabricated with indium–tin-oxide (ITO) p-contacts were investigated as functions of the thickness of the (In)GaN contact layers and the In content. The LEDs with the GaN contact layers showed lower forward voltages (in the range of 3.48–3.03 V) than the LEDs with ITO-only contacts (4.2 V); the forward voltages of the LEDs decreased with increasing contact layer thickness (from 1–4 nm) and increasing In content. However, the output power linearly decreased with increasing In content, whereas that of the GaN contact layer LEDs became saturated at a thickness of 2 nm. The X-ray photoemission spectroscopy (XPS) Ga 2p core level for the samples with the contact layers was shifted toward lower binding energies by 0.11–0.22 eV compared with that of the sample without the contact layer. However, the energy shift decreased with increasing In content. Unlike the contact-layer samples, the sample without the contact layer experienced outdiffusion of N atoms. Based on the XPS and atomic force microscopy results, the contact-layer-induced electrical improvement was described and discussed. (author)

  5. Partition method for impact dynamics of flexible multibody systems based on contact constraint

    Institute of Scientific and Technical Information of China (English)

    段玥晨; 章定国; 洪嘉振

    2013-01-01

    The impact dynamics of a flexible multibody system is investigated. By using a partition method, the system is divided into two parts, the local impact region and the region away from the impact. The two parts are connected by specific boundary conditions, and the system after partition is equivalent to the original system. According to the rigid-flexible coupling dynamic theory of multibody system, system’s rigid-flexible coupling dynamic equations without impact are derived. A local impulse method for establishing the initial impact conditions is proposed. It satisfies the compatibility con-ditions for contact constraints and the actual physical situation of the impact process of flexible bodies. Based on the contact constraint method, system’s impact dynamic equa-tions are derived in a differential-algebraic form. The contact/separation criterion and the algorithm are given. An impact dynamic simulation is given. The results show that system’s dynamic behaviors including the energy, the deformations, the displacements, and the impact force during the impact process change dramatically. The impact makes great effects on the global dynamics of the system during and after impact.

  6. ITON Schottky contacts for GaN based UV photodetectors

    Science.gov (United States)

    Vanhove, N.; John, J.; Lorenz, A.; Cheng, K.; Borghs, G.; Haverkort, J. E. M.

    2006-12-01

    Lateral Schottky ultraviolet detectors were fabricated in GaN using indium-tin-oxynitride (ITON) as a contact metal. The GaN semiconductor material was grown on 2 in. sapphire substrate by metal-organic chemical vapor deposition (MOCVD). The Schottky contact has been realized using ITON that has been deposited using sputter techniques. I- V characteristics have been measured with and without UV illumination. The device shows photo-to-dark current ratios of 10 3 at -1 V bias. The spectral responsivity of the UV detectors has been determined. The high spectral responsivity of more than 30 A/W at 240 nm is explained by a high internal gain caused by generation-recombination centers at the ITON/GaN interface. Persistent photocurrent effect has been observed in UV light (on-off) switching operation, time constant and electron capture coefficient of the transition has been determined.

  7. [Intraocular Pressure Sensor Based on a Contact Lens].

    Science.gov (United States)

    Guo, Xuhong; Pet, Weihua; Yao, Zhaolin; Chen, Yuanfang; Hu, Xiaohui; Chen, Hongda; Zhu, Jingyuan; Wu, Huijuan

    2016-02-01

    Intraocular pressure detection has a great significance for understanding the status of eye health, prevention and treatment of diseases such as glaucoma. Traditional intraocular pressure detection needs to be held in the hospital. It is not only time-consuming to doctors and patients, but also difficult to achieve 24 hour-continuous detection. Microminiaturization of the intraocular pressure sensor and wearing it as a contact lens, which is convenient, comfortable and noninvasive, can solve this problem because the soft contact lens with an embedded micro fabricated strain gauge allows the measurement of changes in corneal curvature to correlate to variations of intraocular pressure. We fabricated a strain gauge using micro-electron mechanical systems, and integrated with the contact lens made of polydimethylsiloxane (PDMS) using injection molding. The experimental results showed that the sensitivity was 100. 7 µV/µm. When attached to the corneal surface, the average sensitivity of sensor response of intraocular pressure can be 125.8 µV/mm Hg under the ideal condition. PMID:27382734

  8. [Intraocular Pressure Sensor Based on a Contact Lens].

    Science.gov (United States)

    Guo, Xuhong; Pet, Weihua; Yao, Zhaolin; Chen, Yuanfang; Hu, Xiaohui; Chen, Hongda; Zhu, Jingyuan; Wu, Huijuan

    2016-02-01

    Intraocular pressure detection has a great significance for understanding the status of eye health, prevention and treatment of diseases such as glaucoma. Traditional intraocular pressure detection needs to be held in the hospital. It is not only time-consuming to doctors and patients, but also difficult to achieve 24 hour-continuous detection. Microminiaturization of the intraocular pressure sensor and wearing it as a contact lens, which is convenient, comfortable and noninvasive, can solve this problem because the soft contact lens with an embedded micro fabricated strain gauge allows the measurement of changes in corneal curvature to correlate to variations of intraocular pressure. We fabricated a strain gauge using micro-electron mechanical systems, and integrated with the contact lens made of polydimethylsiloxane (PDMS) using injection molding. The experimental results showed that the sensitivity was 100. 7 µV/µm. When attached to the corneal surface, the average sensitivity of sensor response of intraocular pressure can be 125.8 µV/mm Hg under the ideal condition.

  9. An infrared-driven flexible pyroelectric generator for non-contact energy harvester.

    Science.gov (United States)

    Zhao, Tingting; Jiang, Weitao; Liu, Hongzhong; Niu, Dong; Li, Xin; Liu, Weihua; Li, Xuan; Chen, Bangdao; Shi, Yongsheng; Yin, Lei; Lu, Bingheng

    2016-04-21

    In recent years, energy harvesting technologies, which can scavenge many kinds of energies from our living environment to power micro/nanodevices, have attracted increasing attention. However, remote energy transmission, flexibility and electric waveform controllability remain the key challenges for wireless power supply by an energy harvester. In this paper, we design a new infrared-driven non-contact pyroelectric generator for harvesting heat energy, which avoids direct contact between the pyroelectric generator and heat source and realizes remote energy transfer exploiting the photothermal and penetrability of infrared light. The output voltage (under the input impedance of 100 MOhm) and short-circuit current of the pyroelectric generator consisting of a CNT/PVDF/CNT layer (20 mm × 5 mm × 100 μm) can be as large as 1.2 V and 9 nA, respectively, under a 1.45 W cm(-2) near-infrared laser (808 nm). We also demonstrate the means by which the pyroelectric generator can modulate square waveforms with controllable periods through irradiation frequency, which is essential for signal sources and medical stimulators. The overshoot of square waveforms are in a range of 9.0%-13.1% with a rise time of 120 ms. The prepared pyroelectric generator can light a liquid crystal display (LCD) in a vacuum chamber from outside. This work paves the way for non-contact energy harvesting for some particular occasions where near-field energy control is not available.

  10. An infrared-driven flexible pyroelectric generator for non-contact energy harvester.

    Science.gov (United States)

    Zhao, Tingting; Jiang, Weitao; Liu, Hongzhong; Niu, Dong; Li, Xin; Liu, Weihua; Li, Xuan; Chen, Bangdao; Shi, Yongsheng; Yin, Lei; Lu, Bingheng

    2016-04-21

    In recent years, energy harvesting technologies, which can scavenge many kinds of energies from our living environment to power micro/nanodevices, have attracted increasing attention. However, remote energy transmission, flexibility and electric waveform controllability remain the key challenges for wireless power supply by an energy harvester. In this paper, we design a new infrared-driven non-contact pyroelectric generator for harvesting heat energy, which avoids direct contact between the pyroelectric generator and heat source and realizes remote energy transfer exploiting the photothermal and penetrability of infrared light. The output voltage (under the input impedance of 100 MOhm) and short-circuit current of the pyroelectric generator consisting of a CNT/PVDF/CNT layer (20 mm × 5 mm × 100 μm) can be as large as 1.2 V and 9 nA, respectively, under a 1.45 W cm(-2) near-infrared laser (808 nm). We also demonstrate the means by which the pyroelectric generator can modulate square waveforms with controllable periods through irradiation frequency, which is essential for signal sources and medical stimulators. The overshoot of square waveforms are in a range of 9.0%-13.1% with a rise time of 120 ms. The prepared pyroelectric generator can light a liquid crystal display (LCD) in a vacuum chamber from outside. This work paves the way for non-contact energy harvesting for some particular occasions where near-field energy control is not available. PMID:27025660

  11. Diagnosis of Constant Faults in Read-Once Contact Networks over Finite Bases using Decision Trees

    KAUST Repository

    Busbait, Monther I.

    2014-05-01

    We study the depth of decision trees for diagnosis of constant faults in read-once contact networks over finite bases. This includes diagnosis of 0-1 faults, 0 faults and 1 faults. For any finite basis, we prove a linear upper bound on the minimum depth of decision tree for diagnosis of constant faults depending on the number of edges in a contact network over that basis. Also, we obtain asymptotic bounds on the depth of decision trees for diagnosis of each type of constant faults depending on the number of edges in contact networks in the worst case per basis. We study the set of indecomposable contact networks with up to 10 edges and obtain sharp coefficients for the linear upper bound for diagnosis of constant faults in contact networks over bases of these indecomposable contact networks. We use a set of algorithms, including one that we create, to obtain the sharp coefficients.

  12. Interfacial Properties of Monolayer and Bilayer MoS2 Contacts with Metals: Beyond the Energy Band Calculations

    Science.gov (United States)

    Zhong, Hongxia; Quhe, Ruge; Wang, Yangyang; Ni, Zeyuan; Ye, Meng; Song, Zhigang; Pan, Yuanyuan; Yang, Jinbo; Yang, Li; Lei, Ming; Shi, Junjie; Lu, Jing

    2016-03-01

    Although many prototype devices based on two-dimensional (2D) MoS2 have been fabricated and wafer scale growth of 2D MoS2 has been realized, the fundamental nature of 2D MoS2-metal contacts has not been well understood yet. We provide a comprehensive ab initio study of the interfacial properties of a series of monolayer (ML) and bilayer (BL) MoS2-metal contacts (metal = Sc, Ti, Ag, Pt, Ni, and Au). A comparison between the calculated and observed Schottky barrier heights (SBHs) suggests that many-electron effects are strongly suppressed in channel 2D MoS2 due to a charge transfer. The extensively adopted energy band calculation scheme fails to reproduce the observed SBHs in 2D MoS2-Sc interface. By contrast, an ab initio quantum transport device simulation better reproduces the observed SBH in 2D MoS2-Sc interface and highlights the importance of a higher level theoretical approach beyond the energy band calculation in the interface study. BL MoS2-metal contacts generally have a reduced SBH than ML MoS2-metal contacts due to the interlayer coupling and thus have a higher electron injection efficiency.

  13. Interfacial Properties of Monolayer and Bilayer MoS2 Contacts with Metals: Beyond the Energy Band Calculations.

    Science.gov (United States)

    Zhong, Hongxia; Quhe, Ruge; Wang, Yangyang; Ni, Zeyuan; Ye, Meng; Song, Zhigang; Pan, Yuanyuan; Yang, Jinbo; Yang, Li; Lei, Ming; Shi, Junjie; Lu, Jing

    2016-01-01

    Although many prototype devices based on two-dimensional (2D) MoS2 have been fabricated and wafer scale growth of 2D MoS2 has been realized, the fundamental nature of 2D MoS2-metal contacts has not been well understood yet. We provide a comprehensive ab initio study of the interfacial properties of a series of monolayer (ML) and bilayer (BL) MoS2-metal contacts (metal = Sc, Ti, Ag, Pt, Ni, and Au). A comparison between the calculated and observed Schottky barrier heights (SBHs) suggests that many-electron effects are strongly suppressed in channel 2D MoS2 due to a charge transfer. The extensively adopted energy band calculation scheme fails to reproduce the observed SBHs in 2D MoS2-Sc interface. By contrast, an ab initio quantum transport device simulation better reproduces the observed SBH in 2D MoS2-Sc interface and highlights the importance of a higher level theoretical approach beyond the energy band calculation in the interface study. BL MoS2-metal contacts generally have a reduced SBH than ML MoS2-metal contacts due to the interlayer coupling and thus have a higher electron injection efficiency.

  14. The Use of Energy Storage Systems for Supporting the Voltage Needs of Urban and Suburban Railway Contact Lines

    Directory of Open Access Journals (Sweden)

    Enrico Pagano

    2013-03-01

    Full Text Available The paper aims to contribute to the use of electric double layer capacitor (EDLC sets for boosting voltages of contact lines in urban and suburban railway traction systems. Different electrical configurations of contact lines are considered and investigated. For each of them, proper mathematical models are suggested to evaluate the electrical performances of the contact lines. They give rise, also, to sample design procedures for the sizing of the most appropriate energy storage systems, to be distributed along the lines, for boosting line voltages and avoiding undesired voltage drops. A numerical example based on the “Cumana” suburban Naples railway network is presented to give an idea of the weights and sizes of electric double layer capacitors needed to boost the voltage of a sample contact line. In particular, three different EDLC systems, for a overall installed energy of 9.6 kWh, have been placed nearby the stations presenting the highest voltage drops during the most representative situation of trains’ service. The new voltage drop is equal to 32% of that obtained in absence of EDLCs.

  15. Effects of Flame Treatment on the Interfacial Energy of Polyethylene Assessed by Contact Mechanics

    NARCIS (Netherlands)

    Song, Jing; Vancso, G. Julius

    2008-01-01

    The effects of flame treatment of low-density polyethylene (LDPE) on the work of adhesion (W) and energy release rate (G) were assessed by a custom-built adhesion testing device (ATD). The contact area and the vertical displacement between planar LDPE films and PDMS lenses (untreated and UV/ozone tr

  16. Subharmonic energy-gap structure and heating effects in superconducting niobium point contacts

    DEFF Research Database (Denmark)

    Flensberg, K.; Hansen, Jørn Bindslev

    1989-01-01

    We present experimental data of the temperature-dependent subharmonic energy-gap structure (SGS) in the current-voltage (I-V) curves of superconducting niobium point contacts. The observed SGS is modified by heating effects. We construct a model of the quasiparticle conductance of metallic...

  17. Energy Absorption and Storage in a Hamiltonian System in Partial Contact with a Heat Bath

    CERN Document Server

    Nakagawa, N; Nakagawa, Naoko; Kaneko, Kunihiko

    1999-01-01

    To understand the mechanism allowing for long-term storage of excess energy in proteins, we study a Hamiltonian system consisting of several coupled pendula in partial contact with a heat bath. It is found that energy absorption and storage are possible when the motion of each pendulum switches between oscillatory (vibrational) and rotational modes. The relevance of our mechanism to protein motors is discussed.

  18. NANOCOMPOSITE POWDERS FOR NEW CONTACT MATERIALS BASED ONCOPPER AND ALUMINA

    Directory of Open Access Journals (Sweden)

    Marija Korać

    2008-11-01

    Full Text Available This paper is a contribution to characterization of Cu-Al2O3 powders with nanostructure designed for the production of dispersion strengthened contact materials. New materials with predetermined properties can be successfully synthesized by utilizing the principles of hydrometallurgy and powder metallurgy. The results show a development of a new procedure for the synthesis. The applied characterization methods were differential thermal and thermogravimetric analysis (DTA-TGA, X-ray diffraction (XRD, scanning electron microscopy (SEM, Transmission Electron Microscopy (TEM: Focused Ion Beam (FIB and Analytical Electron Microscopy (AEM. Nanostructure characteristics, particle size in range 20-50 nm, and uniform distribution of dispersoide in copper matrix were validated.

  19. Electroplated contacts and porous silicon for silicon based solar cells applications

    Energy Technology Data Exchange (ETDEWEB)

    Kholostov, Konstantin, E-mail: kholostov@diet.uniroma1.it [Department of information engineering, electronics and telecommunications, University of Rome “La Sapienza”, Via Eudossiana 18, 00184 Rome (Italy); Serenelli, Luca; Izzi, Massimo; Tucci, Mario [Enea Casaccia Research Centre Rome, via Anguillarese 301, 00123 Rome (Italy); Balucani, Marco [Department of information engineering, electronics and telecommunications, University of Rome “La Sapienza”, Via Eudossiana 18, 00184 Rome (Italy); Rise Technology S.r.l., Lungomare Paolo Toscanelli 170, 00121 Rome (Italy)

    2015-04-15

    Highlights: • Uniformity of the Ni–Si interface is crucial for performance of Cu–Ni contacts on Si. • Uniformly filled PS is the key to obtain the best performance of Cu–Ni contacts on Si. • Optimization of anodization and electroplating allows complete filling of PS layer. • Highly adhesive and low contact resistance Cu–Ni contacts are obtained on Si. - Abstract: In this paper, a two-layer metallization for silicon based solar cells is presented. The metallization consists of thin nickel barrier and thick copper conductive layers, both obtained by electrodeposition technique suitable for phosphorus-doped 70–90 Ω/sq solar cell emitter formed on p-type silicon substrate. To ensure the adhesion between metal contact and emitter a very thin layer of mesoporous silicon is introduced on the emitter surface before metal deposition. This approach allows metal anchoring inside pores and improves silicon–nickel interface uniformity. Optimization of metal contact parameters is achieved varying the anodization and electrodeposition conditions. Characterization of contacts between metal and emitter is carried out by scanning electron microscopy, specific contact resistance and current–voltage measurements. Mechanical strength of nickel–copper contacts is evaluated by the peel test. Adhesion strength of more than 4.5 N/mm and contact resistance of 350 μΩ cm{sup 2} on 80 Ω/sq emitter are achieved.

  20. Parameterizing ice nucleation rates using contact angle and activation energy derived from laboratory data

    Directory of Open Access Journals (Sweden)

    J.-P. Chen

    2008-12-01

    Full Text Available The rate of ice nucleation in clouds is not easily determined and large discrepancies exist between model predictions and actual ice crystal concentration measured in clouds. In an effort to improve the parameterization of ice nucleating in cloud models, we investigate the rate of heterogeneous ice nucleation under specific ambient conditions by knowing the sizes as well as two thermodynamic parameters of the ice nuclei – contact angle and activation energy. Laboratory data of freezing and deposition nucleation modes were analyzed to derive inversely the two thermodynamic parameters for a variety of ice nuclei, including mineral dusts, bacteria, pollens, and soot particles. The analysis considered the Zeldovich factor for the adjustment of ice germ formation, as well as the solute and curvature effects on surface tension; the latter effects have strong influence on the contact angle. Contact angle turns out to be a more important factor than the activation energy in discriminating the nucleation capabilities of various ice nuclei species. By extracting these thermodynamic parameters, laboratory results can be converted into a formulation that follows classical nucleation theory, which then has the flexibility of incorporating factors such as the solute effect and curvature effect that were not considered in the experiments. Due to various uncertainties, contact angle and activation energy derived in this study should be regarded as "apparent" thermodynamics parameters.

  1. Three-dimensional contact analysis of coupled surfaces by a novel contact transformation method based on localized Lagrange multipliers

    Directory of Open Access Journals (Sweden)

    Yi-Tsung Lin

    2016-04-01

    Full Text Available Instead of obsessively emphasizing to reduce the number of time increments and reshape the models, a novel surface contact transformation to increase efficiency is presented in this study. Wear on the bearing surfaces was investigated following the coupled regions from the pressure distribution, computed by means of three-dimensional finite element method models; an approximate analytical model and formulation in three-dimensional frictional contact problems based on modified localized Lagrange multiplier method have also been developed and discussed. Understanding wear behavior patterns in mechanical components is a significant task in engineering design. The proposed approach provides a complete and effective solution to the wear problem in a quasi-dynamic manner. However, expensive computing time is needed in the incremental procedures. In this article, an alternative and efficient finite element approach is introduced to reduce the computation costs of wear prediction. Through the successful verification of wear depth and volume loss of the pin-on-plate, block-on-ring, and metal-on-plastic artificial hip joint wear behaviors, the numerical calculations are shown to be both valid and feasible. Furthermore, the results also show that the central processing unit time required by the proposed method is nearly half that of the previous methods without loss of accuracy.

  2. Microstructure of vanadium-based contacts on n-type GaN

    International Nuclear Information System (INIS)

    Atomic force microscopy, wavelength-dispersive x-ray spectroscopy and photoemission electron microscopy were used to study the contact formation of Au/V/Al/V-based contacts on n-type GaN. After a rapid thermal annealing contact formation step, we find that the surface is composed of dendritic structures. The dendrites are Au-rich, while the voids between the branches of the dendrites are V-rich, and cracks in the voids are Ga-rich. A detailed model of the chemical structure and morphology of V-based contacts on n-GaN is given and discussed in view of the ohmic-like behaviour of such contacts. (paper)

  3. Flip-Chip GaN-Based Light-Emitting Diodes with Mesh-Contact Electrodes

    Institute of Scientific and Technical Information of China (English)

    ZHU Yan-Xu; XU Chen; HAN Jun; SHEN Guang-Di

    2007-01-01

    @@ GaN-based light-emitting diodes (LEDs) with mesh-contact electrodes have been developed. The p-type ohmic contact layer is composed of oxidized Ni/Au mesh and NiO overlay (20 (A)). An Ag (3000 (A)) omni-directional reflector covers the p-type contact. The n-type contact is a Ti/Al planar film with a 10-μm-width Ti/Al stripe.The Ti/Al stripe surrounds the centre of LED mesa. With a 20-mA current injection, the light output power of GaN-based LEDs with mesh-contact electrodes is 23% higher than that of the conventional LEDs.

  4. Voltage waveform to achieve a desired ion energy distribution on a substrate in contact with plasma

    International Nuclear Information System (INIS)

    A methodology is developed to determine the bias voltage waveform needed to achieve a desired (pre-selected) ion energy distribution (IED) on a substrate in contact with plasma. The approach is applicable to collisionless sheaths at all radio frequencies. It combines a circuit model with an equation for a 'damped' sheath potential to which ions respond. The methodology is demonstrated by computing the rf voltage waveform required to achieve a Gaussian IED with specified mean energy and energy spread on an electrode biased through a blocking capacitor. This inverse problem has multiple solutions, i.e. there exists a multitude of waveforms all producing the same IED.

  5. An infrared-driven flexible pyroelectric generator for non-contact energy harvester

    Science.gov (United States)

    Zhao, Tingting; Jiang, Weitao; Liu, Hongzhong; Niu, Dong; Li, Xin; Liu, Weihua; Li, Xuan; Chen, Bangdao; Shi, Yongsheng; Yin, Lei; Lu, Bingheng

    2016-04-01

    In recent years, energy harvesting technologies, which can scavenge many kinds of energies from our living environment to power micro/nanodevices, have attracted increasing attention. However, remote energy transmission, flexibility and electric waveform controllability remain the key challenges for wireless power supply by an energy harvester. In this paper, we design a new infrared-driven non-contact pyroelectric generator for harvesting heat energy, which avoids direct contact between the pyroelectric generator and heat source and realizes remote energy transfer exploiting the photothermal and penetrability of infrared light. The output voltage (under the input impedance of 100 MOhm) and short-circuit current of the pyroelectric generator consisting of a CNT/PVDF/CNT layer (20 mm × 5 mm × 100 μm) can be as large as 1.2 V and 9 nA, respectively, under a 1.45 W cm-2 near-infrared laser (808 nm). We also demonstrate the means by which the pyroelectric generator can modulate square waveforms with controllable periods through irradiation frequency, which is essential for signal sources and medical stimulators. The overshoot of square waveforms are in a range of 9.0%-13.1% with a rise time of 120 ms. The prepared pyroelectric generator can light a liquid crystal display (LCD) in a vacuum chamber from outside. This work paves the way for non-contact energy harvesting for some particular occasions where near-field energy control is not available.In recent years, energy harvesting technologies, which can scavenge many kinds of energies from our living environment to power micro/nanodevices, have attracted increasing attention. However, remote energy transmission, flexibility and electric waveform controllability remain the key challenges for wireless power supply by an energy harvester. In this paper, we design a new infrared-driven non-contact pyroelectric generator for harvesting heat energy, which avoids direct contact between the pyroelectric generator and heat

  6. Thickness dependence of surface energy and contact angle of water droplets on ultrathin MoS2 films.

    Science.gov (United States)

    Guo, Yanhua; Wang, Zhengfei; Zhang, Lizhi; Shen, Xiaodong; Liu, Feng

    2016-06-01

    We have performed a systematic density functional study of surface energy of MoS2 films as a function of thickness from one to twelve layers with the consideration of van der Waals (vdW) interactions using the vdW-DF and DFT-D2 methods. Both vdW schemes show that the surface energy will increase with the increase of the number of atomic layers and converge to a constant value at about six layers. Based on the calculated surface energies, we further analyze the surface contact angle of water droplets on the MoS2 film surface using Young's equation as a function of thickness in comparison with experiments, from which the water-MoS2 interfacial energy is derived to be independent of MoS2 thickness. Our calculations indicate that the vdW interactions between the MoS2 layers play an important role in determining surface energy, and results in the thickness dependence of the contact angle of water droplets on the MoS2 film surface. Our results explain well the recent wetting experiment [Nano Lett., 2014, 14(8), 4314], and will be useful for future studies of physical and chemical properties of ultrathin MoS2 films.

  7. A comparative study of surface energy data from atomic force microscopy and from contact angle goniometry

    Energy Technology Data Exchange (ETDEWEB)

    Lamprou, Dimitrios A.; Smith, James R.; Nevell, Thomas G.; Barbu, Eugen [Biomaterials and Drug Delivery Group, School of Pharmacy and Biomedical Sciences, University of Portsmouth, St. Michael' s Building, White Swan Road, Portsmouth PO1 2DT (United Kingdom); Stone, Corinne; Willis, Colin R. [Physical Sciences Department, Dstl Porton Down, Salisbury SP4 0JQ (United Kingdom); Tsibouklis, John, E-mail: john.tsibouklis@port.ac.uk [Biomaterials and Drug Delivery Group, School of Pharmacy and Biomedical Sciences, University of Portsmouth, St. Michael' s Building, White Swan Road, Portsmouth PO1 2DT (United Kingdom)

    2010-06-01

    Forces of adhesion have been measured for interactions involving self-assembled monolayers or polymer-film structures that had each been deposited onto a gold-coated glass substrate and a probing, gold-coated cantilever. The data have been fitted into mathematical models that allow the calculation of surface energy by considering the work done for the separation of the identically coated contacting surfaces. These values of surface energy are in close agreement with those from corresponding contact angle determinations, highlighting the potential usefulness of the technique for the study of surfaces at a resolution level approaching 1000 atoms. Comparative studies show that the employment of the atomic force microscopy technique may be preferable for the study of samples that are susceptible to penetration by liquids or for investigations under conditions that exceed the useful limits of conventional probing techniques involving liquids.

  8. Planning of Shelf Operation in Dysplastic Hip by CT and MRI Based Finite Element Contact Analysis

    Science.gov (United States)

    Kim, Yoon Hyuk; Park, Won Man; Kim, Kyungsoo; Yoo, Won Joon; Cho, Tae Joon; Choi, In Ho

    Finite element contact analyses of dysplastic hip joints were performed based on CT and MR images as a surgical planning tool of the shelf operation. The 3-D cartilage thickness was approximated using MRI, and the joint contact force was calculated from a 3-D expansion of the Ninomiya’s method. After surgical planning, the anatomical parameters including the CE angle, the AC angle, the sharp angle and the spheric sector angle were improved to normal hips. The mechanical parameters including the maximum contact pressure, the contact area and the quality of contact pressure distribution also were improved. The present models and the results can be used as a computer simulation tool for optimal pre-operative planning of the shelf operation in hip dysplasia.

  9. Contact angle and adsorption energies of nanoparticles at the air-liquid interface determined by neutron reflectivity and molecular dynamics

    Science.gov (United States)

    Reguera, Javier; Ponomarev, Evgeniy; Geue, Thomas; Stellacci, Francesco; Bresme, Fernando; Moglianetti, Mauro

    2015-03-01

    Understanding how nanomaterials interact with interfaces is essential to control their self-assembly as well as their optical, electronic, and catalytic properties. We present here an experimental approach based on neutron reflectivity (NR) that allows the in situ measurement of the contact angles of nanoparticles adsorbed at fluid interfaces. Because our method provides a route to quantify the adsorption and interfacial energies of the nanoparticles in situ, it circumvents problems associated with existing indirect methods, which rely on the transport of the monolayers to substrates for further analysis. We illustrate the method by measuring the contact angle of hydrophilic and hydrophobic gold nanoparticles, coated with perdeuterated octanethiol (d-OT) and with a mixture of d-OT and mercaptohexanol (MHol), respectively. The contact angles were also calculated via atomistic molecular dynamics (MD) computations, showing excellent agreement with the experimental data. Our method opens the route to quantify the adsorption of complex nanoparticle structures adsorbed at fluid interfaces featuring different chemical compositions.Understanding how nanomaterials interact with interfaces is essential to control their self-assembly as well as their optical, electronic, and catalytic properties. We present here an experimental approach based on neutron reflectivity (NR) that allows the in situ measurement of the contact angles of nanoparticles adsorbed at fluid interfaces. Because our method provides a route to quantify the adsorption and interfacial energies of the nanoparticles in situ, it circumvents problems associated with existing indirect methods, which rely on the transport of the monolayers to substrates for further analysis. We illustrate the method by measuring the contact angle of hydrophilic and hydrophobic gold nanoparticles, coated with perdeuterated octanethiol (d-OT) and with a mixture of d-OT and mercaptohexanol (MHol), respectively. The contact angles were

  10. Contact angle and detachment energy of shape anisotropic particles at fluid-fluid interfaces.

    Science.gov (United States)

    Anjali, Thriveni G; Basavaraj, Madivala G

    2016-09-15

    The three phase contact angle of particles, a measure of its wettability, is an important factor that greatly influences their behaviour at interfaces. It is one of the principal design parameters for potential applications of particles as emulsion/foam stabilizers, functional coatings and other novel materials. In the present work, the effect of size, shape and surface chemistry of particles on their contact angle is investigated using the gel trapping technique, which facilitates the direct visualization of the equilibrium position of particles at interfaces. The contact angle of hematite particles of spherocylindrical, peanut and cuboidal shapes, hematite-silica core-shell and silica shells is reported at a single particle level. The spherocylindrical and peanut shaped particles are always positioned with their major axis parallel to the interface. However, for cuboidal particles at air-water as well as decane-water interfaces, different orientations namely - face-up, edge-up and the vertex-up - are observed. The influence of gravity on the equilibrium position of the colloidal particles at the interface is studied using the hematite-silica core-shell particles and the silica shells. The measured contact angle values are utilized in the calculations of the detachment and surface energies of the hematite particles adsorbed at the interface. PMID:27285780

  11. Nanoscale contacts to organic molecules based on layered semiconductor substrates

    Energy Technology Data Exchange (ETDEWEB)

    Strobel, Sebastian

    2009-06-15

    This work reports on the integration of organic molecules as nanoelectronic device units on semiconductor substrates. Two novel preparation methods for sub-10-nm separated metal electrodes are presented using current microelectronics process technology. The first method utilises AlGaAs/GaAs heterostructures grown by molecular beam epitaxy (MBE) as mold to create planar metal electrodes employing a newly developed, high resolution nanotransfer printing (nTP) process. The second method uses commercially available Silicon-on-Insulator (SOI) substrates as base material for the fabrication of nanogap electrode devices. This sandwich-like material stack consists of a silicon substrate, a thin silicon oxide layer, and a capping silicon layer on top. Electronic transport measurements verified their excellent electrical properties at liquid helium temperatures. Specifically tailored nanogap devices featured an electrode insulation in the GW range even up to room temperature as well as within aqueous electrolyte solution. Finally, the well defined layer architecture facilitated the fabrication of electrodes with gap separations below-10-nm to be directly bridged by molecules. Approximately 12-nm-long conjugated molecules with extended -electron system were assembled onto the devices from solution. A large conductance gap was observed with a steep increase in current at a bias voltage of V{sub T}{approx}{+-}1.5 V. Theoretical calculations based on density functional theory and non-equilibrium Green's function formalism confirmed the measured non-linear IV-characteristics qualitatively and lead to the conclusion that the conductance gap mainly originates from the oxygen containing linker. Temperature dependent investigations of the conductance indicated a hopping charge transport mechanism through the central part of the molecule for bias voltages near but below V{sub T}. (orig.)

  12. Thermally stable AuBe-based ohmic contacts to p-type GaP for AlGaInP-based light-emitting diode by using a tungsten barrier layer

    Science.gov (United States)

    Kim, Dae-Hyun; Kang, Daesung; Park, Jae-Seong; Seong, Tae-Yeon

    2016-01-01

    We investigated how a tungsten diffusion barrier layer affected the electrical properties of AuBe/Au contacts to a p-GaP window layer (na = 5 × 1019 cm-3) for an AlGaInP-based light emitting diode. All of the as-deposited samples were ohmic. After annealing at 500 °C, the AuBe/Au contacts were electrically degraded with a specific contact resistivity of 1.0 × 10-4 Ωcm2. However, the electrical properties of the W-based contacts were improved, having a contact resistivity of 5.0 × 10-6 Ωcm2. The X-ray photoemission spectroscopy (XPS) results showed that the Ga 2 p core level for the annealed AuBe/Au contacts shifted to the high binding-energy side. On the other hand, that for the AuBe/W/Au contacts shifted toward the lower binding-energy side. For the AuBe/Au contacts, both Be and P atoms were shown to be outdiffused into the metal contact after annealing. However, for the AuBe/W/Au contacts, the outdiffusion of Be atoms was prevented by the W barrier layer, and the Be atoms were indiffused into GaP. Based on the X-ray photoemission spectroscopy (XPS), Auger electron spectroscopy (AES), and electrical results, the annealing-induced electrical degradation and improvement are described and discussed.

  13. Role of Metal Contacts in High-Performance Phototransistors Based on WSe 2 Monolayers

    KAUST Repository

    Zhang, Wenjing

    2014-08-26

    Phototransistors based on monolayer transition metal dichalcogenides (TMD) have high photosensitivity due to their direct band gap transition. However, there is a lack of understanding of the effect of metal contacts on the performance of atomically thin TMD phototransistors. Here, we fabricate phototransistors based on large-area chemical vapor deposition (CVD) tungsten diselenide (WSe2) monolayers contacted with the metals of different work function values. We found that the low Schottky-contact WSe2 phototransistors exhibit a very high photo gain (105) and specific detectivity (1014Jones), values higher than commercial Si- and InGaAs-based photodetectors; however, the response speed is longer than 5 s in ambient air. In contrast, the high Schottky-contact phototransistors display a fast response time shorter than 23 ms, but the photo gain and specific detectivity decrease by several orders of magnitude. Moreover, the fast response speed of the high Schottky-contact devices is maintained for a few months in ambient air. This study demonstrates that the contact plays an important role in TMD phototransistors, and barrier height tuning is critical for optimizing the photoresponse and photoresponsivity. © 2014 American Chemical Society.

  14. Complex Contact-Based Dynamics of Microsphere Monolayers Revealed by Resonant Attenuation of Surface Acoustic Waves

    Science.gov (United States)

    Hiraiwa, M.; Abi Ghanem, M.; Wallen, S. P.; Khanolkar, A.; Maznev, A. A.; Boechler, N.

    2016-05-01

    Contact-based vibrations play an essential role in the dynamics of granular materials. Significant insights into vibrational granular dynamics have previously been obtained with reduced-dimensional systems containing macroscale particles. We study contact-based vibrations of a two-dimensional monolayer of micron-sized spheres on a solid substrate that forms a microscale granular crystal. Measurements of the resonant attenuation of laser-generated surface acoustic waves reveal three collective vibrational modes that involve displacements and rotations of the microspheres, as well as interparticle and particle-substrate interactions. To identify the modes, we tune the interparticle stiffness, which shifts the frequency of the horizontal-rotational resonances while leaving the vertical resonance unaffected. From the measured contact resonance frequencies we determine both particle-substrate and interparticle contact stiffnesses and find that the former is an order of magnitude larger than the latter. This study paves the way for investigating complex contact-based dynamics of microscale granular crystals and yields a new approach to studying micro- to nanoscale contact mechanics in multiparticle networks.

  15. A novel methodology based on contact angle hysteresis approach for surface changes monitoring in model PMMA-Corega Tabs system

    Science.gov (United States)

    Pogorzelski, Stanisław J.; Berezowski, Zdzisław; Rochowski, Paweł; Szurkowski, Janusz

    2012-02-01

    The aim of the paper is to propose a quantitative description of dental surface modifications, resulting from application of Corega and oral cavity liquids, with several surface parameters derived from liquid/solid contact angle measurements. In particular, to predict the long-term effectiveness of denture cleansers in prosthetics, it is necessary to determine surface wettability variations for model dental materials/probe liquid systems related to the contamination effect caused by substances found in the oral cavity. A novel simple low-cost methodology, based on liquid drop contact angle hysteresis CAH approach developed by Chibowski, was adopted to trace solid surface free energy changes in the model PMMA-Corega Tabs interfacial layer. Contact angle and its hysteresis were studied with a sessile drop-inclined plate method in contact with a cleanser (Corega Tabs) and model liquids found in the oral cavity. The apparent solid surface free energy, adsorptive film pressure, work of adhesion and spreading were derived from contact angle hysteresis data for both model solid surfaces (reference) and samples affected by different reactive liquids for a certain time. A time-dependent surface wettability changes of dentures were expressed quantitatively in terms of the corresponding variations of the surface energy parameters which turned out to be unequivocally related to the cleanser exposure time and polarity of the liquids applied to the dental material. The novel methodology appeared to be a useful tool for long term surface characterization of dental materials treated with surfactants-containing liquids capable of forming adhesive layers. The time of optimal use and effectiveness of cleansers are also reflected dynamically in the corresponding variations of the surface wettability parameters. Further studies on a large group of dental surface-probe liquid systems are required to specify the role played by other important factors (liquid polarity, pH and temperature).

  16. Contact angle adjustment in equation-of-state-based pseudopotential model.

    Science.gov (United States)

    Hu, Anjie; Li, Longjian; Uddin, Rizwan; Liu, Dong

    2016-05-01

    The single component pseudopotential lattice Boltzmann model has been widely applied in multiphase simulation due to its simplicity and stability. In many studies, it has been claimed that this model can be stable for density ratios larger than 1000. However, the application of the model is still limited to small density ratios when the contact angle is considered. The reason is that the original contact angle adjustment method influences the stability of the model. Moreover, simulation results in the present work show that, by applying the original contact angle adjustment method, the density distribution near the wall is artificially changed, and the contact angle is dependent on the surface tension. Hence, it is very inconvenient to apply this method with a fixed contact angle, and the accuracy of the model cannot be guaranteed. To solve these problems, a contact angle adjustment method based on the geometry analysis is proposed and numerically compared with the original method. Simulation results show that, with our contact angle adjustment method, the stability of the model is highly improved when the density ratio is relatively large, and it is independent of the surface tension. PMID:27301005

  17. Definition and detection of contact in atomistic simulations

    NARCIS (Netherlands)

    Solhjoo, Soheil; Vakis, Antonis I.

    2015-01-01

    In atomistic simulations, contact depends on the accurate detection of contacting atoms as well as their contact area. While it is common to define contact between atoms based on the so-called ‘contact distance’ where the interatomic potential energy reaches its minimum, this discounts, for example,

  18. Characterization of nanophotonic soft contact lenses based on poly (2-hydroxyethyl methacrylate and fullerene

    Directory of Open Access Journals (Sweden)

    Debeljković Aleksandra D.

    2013-01-01

    Full Text Available This work presents comparative research of characteristics of a basic and new nanophotonic material, the latter of which was obtained by incorporation fullerene, C60, in the base material for soft contact lenses. The basic (SL38 and nanophotonic materials (SL38-A for soft contact lenses were obtained by radical polymerization of 2-hydroxyethyl methacrylate and 2-hydroxyethyl methacrylate and fullerene, which were derived by the technology in the production lab of the company Soleko (Milan, Italy. The materials were used for production of soft contact lenses in the company Optix (Belgrade, Serbia for the purposes of this research. Fullerene was used due to its apsorption transmission characteristics in ultraviolet, visible and near infrared spectrum. For the purposes of material characterization for potential application as soft contact lenses, network parameters were calculated and SEM analysis of the materials was performed while the optical properties of the soft contact lenses were measured by a Rotlex device. The values of the diffusion exponent, n, close to 0.5 indicated Fick's kinetics corresponding to diffusion. The investigated hydrogels could be classified as nonporous hydrogels. With Rotlex device, values of optical power and map of defects were showed. The obtained values of optical power and map of defects showed that the optical power of synthesized nanophotonic soft contact lens is identical to the nominal value while this was not the case for the basic lens. Also, the quality of the nanophotonic soft contact lens is better than the basic soft contact lens. Hence, it is possible to synthesize new nanophotonic soft contact lenses of desired optical characteristics, implying possibilities for their application in this field.

  19. Properties of Contact Resistance towards Realization of Graphene-based Three-Branch Junction Device

    Science.gov (United States)

    Rahman, S. F. A.; Hashim, A. M.; Ali, N. K.; Rusop, M.; Nafarizal, N.

    2011-05-01

    A three-branch junction (TBJ) nanowire device is shown to exhibit a unique nonlinear input-output characteristics. The effect of contact resistance on such characteristics is investigated. It is shown that metal contact having small contact resistance is required so that such nonlinear characteristics of TBJ device can be maintained. The graphene-based back-gated FET device structure and transmission line method are proposed and discussed in order to determine the contact resistance of metal/graphene interface. The preparation of graphene layer and its characterization using conventional methods are presented and discussed. These basic preliminary results provide useful guidance and information for the fabrication of actual devices which are on the way.

  20. Intracavity contacts for nitride based monolithic surface emitters by focused ion beam processing

    Energy Technology Data Exchange (ETDEWEB)

    Fandrich, Malte; Dartsch, Heiko; Tessarek, Christian; Aschenbrenner, Timo; Hommel, Detlef [Institut fuer Festkoerperphysik - Halbleiterepitaxie, Universitaet Bremen (Germany)

    2010-07-01

    The realization of electrically driven nitride based vertical-cavity surface-emitting lasers (VCSELs) is challenging due to limitations in the conductivity of the distributed Bragg reflectors (DBRs). Therefore monolithic approaches are based on a doped cavity and one or two undoped DBRs. This requires the use of technologically complex intracavity contacts. The presented process yields intracavity contacts applicable to monolithically grown VCSEL structures. Initially mesas are structured by photolithography and chemical assisted ion beam etching. The precise structuring of the prestructured mesas is performed in a focused ion beam system (FIB), where the micropillars are thinned stepwise down to a diameter of 0.5-5 {mu}m. The contacting of the pillars is realized by FIB deposited metal and insulator structures. Insulator separated Pt ring-contacts connect the micropillars with large-scale contact pads. This procedure was applied to a VCSEL structure consisting of a bottom AlInN/GaN-DBR with 40 pairs, a p/n-doped 5 {lambda} GaN-cavity with embedded InGaN quantum dots and a top 10 pair AlInN/GaN-DBR. The developed contacting structure enables a current up to 15 mA through the cavity which documents the capability for the electrical operation of VCSEL devices.

  1. Drops on soft solids: Free energy and double transition of contact angles

    CERN Document Server

    Lubbers, Luuk A; Botto, Lorenzo; Das, Siddhartha; Andreotti, Bruno; Snoeijer, Jacco H

    2013-01-01

    The equilibrium shape of liquid drops on elastic substrates is determined by minimising elastic and capillary free energies. The problem is governed by three length scales: the size of the drop $R$, the molecular size $a$, and the ratio of surface tension to elastic modulus $\\gamma/E$. We show that the contact angles undergo two transitions upon changing the substrates from rigid to soft. The microscopic wetting angles deviate from Young's law when $\\gamma/Ea \\gg 1$, while the apparent macroscopic angle only changes in the very soft limit $\\gamma/ER \\gg 1$. Details of the elastic deformations are worked out in the simplifying case where the surface energy of the solid is assumed independent of the elastic strain. The total free energy is found to be lowest on softer substrates, consistent with recent experiments. Finally, we discuss how the variational framework can be generalized to properly account for surface stress.

  2. Contact- and distance-based principal component analysis of protein dynamics

    International Nuclear Information System (INIS)

    To interpret molecular dynamics simulations of complex systems, systematic dimensionality reduction methods such as principal component analysis (PCA) represent a well-established and popular approach. Apart from Cartesian coordinates, internal coordinates, e.g., backbone dihedral angles or various kinds of distances, may be used as input data in a PCA. Adopting two well-known model problems, folding of villin headpiece and the functional dynamics of BPTI, a systematic study of PCA using distance-based measures is presented which employs distances between Cα-atoms as well as distances between inter-residue contacts including side chains. While this approach seems prohibitive for larger systems due to the quadratic scaling of the number of distances with the size of the molecule, it is shown that it is sufficient (and sometimes even better) to include only relatively few selected distances in the analysis. The quality of the PCA is assessed by considering the resolution of the resulting free energy landscape (to identify metastable conformational states and barriers) and the decay behavior of the corresponding autocorrelation functions (to test the time scale separation of the PCA). By comparing results obtained with distance-based, dihedral angle, and Cartesian coordinates, the study shows that the choice of input variables may drastically influence the outcome of a PCA

  3. Contact- and distance-based principal component analysis of protein dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Matthias; Sittel, Florian; Stock, Gerhard, E-mail: stock@physik.uni-freiburg.de [Biomolecular Dynamics, Institute of Physics, Albert Ludwigs University, 79104 Freiburg (Germany)

    2015-12-28

    To interpret molecular dynamics simulations of complex systems, systematic dimensionality reduction methods such as principal component analysis (PCA) represent a well-established and popular approach. Apart from Cartesian coordinates, internal coordinates, e.g., backbone dihedral angles or various kinds of distances, may be used as input data in a PCA. Adopting two well-known model problems, folding of villin headpiece and the functional dynamics of BPTI, a systematic study of PCA using distance-based measures is presented which employs distances between C{sub α}-atoms as well as distances between inter-residue contacts including side chains. While this approach seems prohibitive for larger systems due to the quadratic scaling of the number of distances with the size of the molecule, it is shown that it is sufficient (and sometimes even better) to include only relatively few selected distances in the analysis. The quality of the PCA is assessed by considering the resolution of the resulting free energy landscape (to identify metastable conformational states and barriers) and the decay behavior of the corresponding autocorrelation functions (to test the time scale separation of the PCA). By comparing results obtained with distance-based, dihedral angle, and Cartesian coordinates, the study shows that the choice of input variables may drastically influence the outcome of a PCA.

  4. Investigation of energy dissipation due to contact angle hysteresis in capillary effect

    Science.gov (United States)

    Athukorallage, Bhagya; Iyer, Ram

    2016-06-01

    Capillary action or Capillarity is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to, external forces like gravity. Three effects contribute to capillary action, namely, adhesion of the liquid to the walls of the confining solid; meniscus formation; and low Reynolds number fluid flow. We investigate the dissipation of energy during one cycle of capillary action, when the liquid volume inside a capillary tube first increases and subsequently decreases while assuming quasi-static motion. The quasi-static assumption allows us to focus on the wetting phenomenon of the solid wall by the liquid and the formation of the meniscus. It is well known that the motion of a liquid on an non-ideal surface involves the expenditure of energy due to contact angle hysteresis. In this paper, we derive the equations for the menisci and the flow rules for the change of the contact angles for a liquid column in a capillary tube at a constant temperature and volume by minimizing the Helmholtz free energy using calculus of variations. We describe the numerical solution of these equations and present results from computations for the case of a capillary tube with 1 mm diameter.

  5. Effectiveness of contact-based education for reducing mental illness-related stigma in pharmacy students

    Directory of Open Access Journals (Sweden)

    Patten Scott B

    2012-12-01

    Full Text Available Abstract Background A strategy for reducing mental illness-related stigma in health-profession students is to include contact-based sessions in their educational curricula. In such sessions students are able to interact socially with a person that has a mental illness. We sought to evaluate the effectiveness of this strategy in a multi-centre study of pharmacy students. Methods The study was a randomized controlled trial conducted at three sites. Because it was necessary that all students receive the contact-based sessions, the students were randomized either to an early or late intervention, with the late intervention group not having participated in the contact-based education at the time when the primary outcome was assessed. The primary outcome, stigma, was assessed using an attitudes scale called the Opening Minds Survey for Health Care Providers (OMS-HC. Results We initially confirmed that outcomes were homogeneous across study centres, centre by group interaction, p = 0.76. The results were pooled across the three study centres. A significant reduction in stigma was observed in association with the contact-based sessions (mean change 4.3 versus 1.5, t=2.1, p=0.04. The effect size (Cohen’s d was 0.45. A similar reduction was seen in the control group when they later received the intervention. Conclusions Contact-based education is an effective method of reducing stigma during pharmacy education. These results add to a growing literature confirming the effectiveness of contact-based strategies for stigma reduction in health profession trainees.

  6. On the physically based modeling of surface tension and moving contact lines with dynamic contact angles on the continuum scale

    Science.gov (United States)

    Huber, M.; Keller, F.; Säckel, W.; Hirschler, M.; Kunz, P.; Hassanizadeh, S. M.; Nieken, U.

    2016-04-01

    The description of wetting phenomena is a challenging problem on every considerable length-scale. The behavior of interfaces and contact lines on the continuum scale is caused by intermolecular interactions like the Van der Waals forces. Therefore, to describe surface tension and the resulting dynamics of interfaces and contact lines on the continuum scale, appropriate formulations must be developed. While the Continuum Surface Force (CSF) model is well-engineered for the description of interfaces, there is still a lack of treatment of contact lines, which are defined by the intersection of an ending fluid interface and a solid boundary surface. In our approach we use a balance equation for the contact line and extend the Navier-Stokes equations in analogy to the extension of a two-phase interface in the CSF model. Since this model depicts a physically motivated approach on the continuum scale, no fitting parameters are introduced and the deterministic description leads to a dynamical evolution of the system. As verification of our theory, we show a Smoothed Particle Hydrodynamics (SPH) model and simulate the evolution of droplet shapes and their corresponding contact angles.

  7. A Hydrogel-Based Hybrid Theranostic Contact Lens for Fungal Keratitis.

    Science.gov (United States)

    Huang, Jian-Fei; Zhong, Jing; Chen, Guo-Pu; Lin, Zuan-Tao; Deng, Yuqing; Liu, Yong-Lin; Cao, Piao-Yang; Wang, Bowen; Wei, Yantao; Wu, Tianfu; Yuan, Jin; Jiang, Gang-Biao

    2016-07-26

    Fungal keratitis, a severe ocular disease, is one of the leading causes of ocular morbidity and blindness, yet it is often neglected, especially in developing countries. Therapeutic efficacy of traditional treatment such as eye drops is very limited due to poor bioavailability, whereas intraocular injection might cause serious side effects. Herein, we designed and fabricated a hybrid hydrogel-based contact lens which comprises quaternized chitosan (HTCC), silver nanoparticles, and graphene oxide (GO) with a combination of antibacterial and antifungal functions. The hydrogel is cross-linked through electrostatic interactions between GO and HTCC, resulting in strong mechanical properties. Voriconazole (Vor), an antifungal drug, can be loaded onto GO which retains the drug and promotes its sustained release from the hydrogel-based contact lenses. The contact lenses also exhibited good antimicrobial functions in view of glycidyltrimethylammonium chloride and silver nanoparticles. The results from in vitro and in vivo experiments demonstrate that contact lenses loaded with Vor have excellent efficacy in antifungal activity in vitro and could significantly enhance the therapeutic effects on a fungus-infected mouse model. The results indicate that this hydrogel contact lenses-based drug delivery system might be a promising therapeutic approach for a rapid and effective treatment of fungal keratitis. PMID:27244244

  8. Machine Vision Based Measurement of Dynamic Contact Angles in Microchannel Flows

    Institute of Scientific and Technical Information of China (English)

    Valtteri Heiskanen; Kalle Marjanen; Pasi Kallio

    2008-01-01

    When characterizing flows in miniaturized channels, the determination of the dynamic contact angle is important. By measuring the dynamic contact angle, the flow properties of the flowing liquid and the effect of material properties on the flow can be characterized. A machine vision based system to measure the contact angle of front or rear menisci of a moving liquid plug is described in this article. In this research, transparent flow channels fabricated on thermoplastic polymer and scaled with an adhesive tape are used. The transparency of the channels enables image based monitoring and measurement of flow variables, including the dynamic contact angle. It is shown that the dynamic angle can be measured from a liquid flow in a channel using the image based measurement system. An image processing algorithm has been developed in a MATLAB environment. Im-ages are taken using a CCD camera and the channels are illuminated using a custom made ring light. Two fitting methods, a circle and two parabolas, are experimented and the results are compared in the measurement of the dynamic contact angles.

  9. Fabrication and Analysis of Micro Contact Based Probe Cell for IC Testing

    Directory of Open Access Journals (Sweden)

    M. Idzdihar Idris

    2015-06-01

    Full Text Available This study presents the fabrication process and analysis of micro contact probe cell for IC testing deposited by dc sputtering technique on a glass substrate. It is designed to solve and replace pogo pins in IC testing process. In previous study, the new model of test socket with new materials in different shapes were designed by using ANSYS as Finite Element Analysis (FEA software and the best parameter were obtained. According to the optimized parameters, prototype structures of the micro-contacts are fabricated using DC Sputtering with materials like copper and tungsten on base copper on glass substrates. Micro contact with thickness of 2800-7000 nm were successively deposited on glass substrate at sputtering power of 125 W in argon ambient gas with pressure of 10-15multiply 10-3 Torr at a room temperature. The structural and electrical properties of micro contact were investigated by using profilometer, Scanning Electron Microscopy (SEM, Atomic Force Microscopy (AFM and four point probes. Results show that the film thickness increased as the deposition the time getting longer. The Root Mean Square (RMS roughnesses obtained are all in a good quality. On the other hand, the resistivity of micro contacts was less than 4 u&Omega-cm, which has good conductive properties. Consequently, this design is appropriate for replacing the conventional pogo pin based testing tools.

  10. ULTRACOATINGS: Enabling Energy and Power Solutions in High Contact Stress Environments through Next-Generation Nanocoatings

    Energy Technology Data Exchange (ETDEWEB)

    Blau, P.; Qu, J.; Higdon, C. III (Eaton Corp.)

    2011-09-30

    This industry-driven project was the result of a successful response by Eaton Corporation to a DOE/ITP Program, Grand Challenge, industry call. It consisted of a one-year effort in which ORNL participated in the area of friction and wear testing. In addition to Eaton Corporation and ORNL (CRADA), the project team included: Ames Laboratory, who developed the underlying concept for titanium- zirconium-boron (TZB) based nanocomposite coatings; Borg-Warner Morse TEC, an automotive engine timing chain manufacturer in Ithaca, New York, with its own proprietary hard coating; and Pratt & Whitney Rocketdyne, Inc., a dry-solids pump manufacturer in San Fernando Valley, California. This report focuses only on the portion of work that was conducted by ORNL, in a CRADA with Eaton Corporation. A comprehensive final report for the entire effort, which ended in September 2010, has been prepared for DOE by the team. The term 'ultracoatings' derives from the ambitious technical target for the new generation of nanocoatings. As applications, Eaton was specifically considering a fuel pump and a gear application in which the product of the contact pressure and slip velocity during operation of mating surfaces, commonly called the 'PV value', was equal to or greater than 70,000 MPa-m/s. This ambitious target challenges the developers of coatings to produce material capable of strong bonding to the substrate, as well as high wear resistance and the ability to maintain sliding friction at low, energy-saving levels. The partners in this effort were responsible for the selection and preparation of such candidate ultracoatings, and ORNL used established tribology testing capabilities to help screen these candidates for performance. This final report summarizes ORNL's portion of the nanocomposite coatings development effort and presents both generated data and the analyses that were used in the course of this effort. Initial contact stress and speed calculations

  11. A reference guide to microbial cell surface hydrophobicity based on contact angles

    NARCIS (Netherlands)

    van der Mei, HC; Busscher, HJ; Bos, R.R.M.

    1998-01-01

    Acid-base interactions form the origin of the hydrophobicity of microbial cell-surfaces and can be quantitated from contact angle measurements on microbial lawns with water, formamide, methyleneiodide and/or alpha-bromonaphthalene. This review provides a reference guide to microbial cell surface hyd

  12. Solving frictional contact problems by two aggregate-function-based algorithms

    Institute of Scientific and Technical Information of China (English)

    Suyan He; Hongwu Zhang; Xingsi Li; Ron Marshall

    2005-01-01

    Three dimensional frictional contact problems are formulated as linear complementarity problems based on the parametric variational principle. Two aggregate-functionbased algorithms for solving complementarity problems are proposed. One is called the self-adjusting interior point algorithm, the other is called the aggregate function smoothing algorithm. Numerical experiment shows the efficiency of the proposed two algorithms.

  13. Friendly-Sharing: Improving the Performance of City Sensoring through Contact-Based Messaging Applications.

    Science.gov (United States)

    Herrera-Tapia, Jorge; Hernández-Orallo, Enrique; Tomás, Andrés; Manzoni, Pietro; Tavares Calafate, Carlos; Cano, Juan-Carlos

    2016-09-18

    Regular citizens equipped with smart devices are being increasingly used as "sensors" by Smart Cities applications. Using contacts among users, data in the form of messages is obtained and shared. Contact-based messaging applications are based on establishing a short-range communication directly between mobile devices, and on storing the messages in these devices for subsequent delivery to cloud-based services. An effective way to increase the number of messages that can be shared is to increase the contact duration. We thus introduce the Friendly-Sharing diffusion approach, where, during a contact, the users are aware of the time needed to interchange the messages stored in their buffers, and they can thus decide to wait more time in order to increase the message sharing probability. The performance of this approach is anyway closely related to the size of the buffer in the device. We therefore compare various policies either for the message selection at forwarding times and for message dropping when the buffer is full. We evaluate our proposal with a modified version of the Opportunistic Networking Environment (ONE) simulator and using real human mobility traces.

  14. Friendly-Sharing: Improving the Performance of City Sensoring through Contact-Based Messaging Applications

    Directory of Open Access Journals (Sweden)

    Jorge Herrera-Tapia

    2016-09-01

    Full Text Available Regular citizens equipped with smart devices are being increasingly used as “sensors” by Smart Cities applications. Using contacts among users, data in the form of messages is obtained and shared. Contact-based messaging applications are based on establishing a short-range communication directly between mobile devices, and on storing the messages in these devices for subsequent delivery to cloud-based services. An effective way to increase the number of messages that can be shared is to increase the contact duration. We thus introduce the Friendly-Sharing diffusion approach, where, during a contact, the users are aware of the time needed to interchange the messages stored in their buffers, and they can thus decide to wait more time in order to increase the message sharing probability. The performance of this approach is anyway closely related to the size of the buffer in the device. We therefore compare various policies either for the message selection at forwarding times and for message dropping when the buffer is full. We evaluate our proposal with a modified version of the Opportunistic Networking Environment (ONE simulator and using real human mobility traces.

  15. Friendly-Sharing: Improving the Performance of City Sensoring through Contact-Based Messaging Applications

    Science.gov (United States)

    Herrera-Tapia, Jorge; Hernández-Orallo, Enrique; Tomás, Andrés; Manzoni, Pietro; Tavares Calafate, Carlos; Cano, Juan-Carlos

    2016-01-01

    Regular citizens equipped with smart devices are being increasingly used as “sensors” by Smart Cities applications. Using contacts among users, data in the form of messages is obtained and shared. Contact-based messaging applications are based on establishing a short-range communication directly between mobile devices, and on storing the messages in these devices for subsequent delivery to cloud-based services. An effective way to increase the number of messages that can be shared is to increase the contact duration. We thus introduce the Friendly-Sharing diffusion approach, where, during a contact, the users are aware of the time needed to interchange the messages stored in their buffers, and they can thus decide to wait more time in order to increase the message sharing probability. The performance of this approach is anyway closely related to the size of the buffer in the device. We therefore compare various policies either for the message selection at forwarding times and for message dropping when the buffer is full. We evaluate our proposal with a modified version of the Opportunistic Networking Environment (ONE) simulator and using real human mobility traces. PMID:27649209

  16. Friendly-Sharing: Improving the Performance of City Sensoring through Contact-Based Messaging Applications.

    Science.gov (United States)

    Herrera-Tapia, Jorge; Hernández-Orallo, Enrique; Tomás, Andrés; Manzoni, Pietro; Tavares Calafate, Carlos; Cano, Juan-Carlos

    2016-01-01

    Regular citizens equipped with smart devices are being increasingly used as "sensors" by Smart Cities applications. Using contacts among users, data in the form of messages is obtained and shared. Contact-based messaging applications are based on establishing a short-range communication directly between mobile devices, and on storing the messages in these devices for subsequent delivery to cloud-based services. An effective way to increase the number of messages that can be shared is to increase the contact duration. We thus introduce the Friendly-Sharing diffusion approach, where, during a contact, the users are aware of the time needed to interchange the messages stored in their buffers, and they can thus decide to wait more time in order to increase the message sharing probability. The performance of this approach is anyway closely related to the size of the buffer in the device. We therefore compare various policies either for the message selection at forwarding times and for message dropping when the buffer is full. We evaluate our proposal with a modified version of the Opportunistic Networking Environment (ONE) simulator and using real human mobility traces. PMID:27649209

  17. Diagnosis of constant faults in read-once contact networks over finite bases

    KAUST Repository

    Busbait, Monther I.

    2015-03-01

    We study the depth of decision trees for diagnosis of constant 0 and 1 faults in read-once contact networks over finite bases containing only indecomposable networks. For each basis, we obtain a linear upper bound on the minimum depth of decision trees depending on the number of edges in the networks. For bases containing networks with at most 10 edges we find coefficients for linear bounds which are close to sharp. © 2014 Elsevier B.V. All rights reserved.

  18. Diagnosis of three types of constant faults in read-once contact networks over finite bases

    KAUST Repository

    Busbait, Monther

    2016-03-24

    We study the depth of decision trees for diagnosis of three types of constant faults in read-once contact networks over finite bases containing only indecomposable networks. For each basis and each type of faults, we obtain a linear upper bound on the minimum depth of decision trees depending on the number of edges in networks. For bases containing networks with at most 10 edges, we find sharp coefficients for linear bounds.

  19. Workshop on Direct Contact Heat Transfer at the Solar Energy Research Institute

    CERN Document Server

    Boehm, R

    1988-01-01

    to increase the use of direct contact processes, the National Science Foundation sup­ ported a workshop on direct contact heat transfer at the Solar Energy Research Insti­ tute in the summer of 1985. We served as organizers for this workshop, which em­ phasized an area of thermal engineering that, in our opinion, has great promise for the future, but has not yet reached the point of wide-spread commercial application. Hence, a summary of the state of knowledge at this point is timely. The workshop had a dual objective: 1. To summarize the current state of knowledge in such a form that industrial practi­ tioners can make use of the available information. 2. To indicate the research and development needed to advance the state-of-the-art, indicating not only what kind of research is needed, but also the industrial poten­ tial that could be realized if the information to be obtained through the proposed research activities were available.

  20. A capacitor-based sensor and a contact lens sensing system for intraocular pressure monitoring

    Science.gov (United States)

    Chiou, Jin-Chern; Huang, Yu-Chieh; Yeh, Guan-Ting

    2016-01-01

    This study proposes a capacitor-based sensor on a soft contact lens for the measurement of intraocular pressure (IOP). The sensor was designed and fabricated via microelectromechanical system fabrication technologies. The soft contact lens is designed to be worn on a cornea such that the curvature of the contact lens corresponds substantially to that of the cornea. In addition, the contact lens was fabricated via a cast-molding method using poly-2-hydroxyethyl methacrylate to achieve a lens with high oxygen permeability, which can be worn comfortably for a long time. An IOP sensor prototype was implemented, which exhibited 1.2239 pF mmHg-1 (13,171 ppm mmHg-1) sensitivity during measurements of an artificial anterior chamber at pressures between 18 and 30 mmHg. The results indicate that the developed capacitor-based IOP sensor exhibited high stability and reproducibility in a series of measurements performed under various pressures. The capacitance of the proposed IOP sensor can successfully be converted into a digital value via a capacitor-to-digital converter and be transmitted via a commercial wireless telemetry system in this study.

  1. Design, fabrication and skin-electrode contact analysis of polymer microneedle-based ECG electrodes

    Science.gov (United States)

    O'Mahony, Conor; Grygoryev, Konstantin; Ciarlone, Antonio; Giannoni, Giuseppe; Kenthao, Anan; Galvin, Paul

    2016-08-01

    Microneedle-based ‘dry’ electrodes have immense potential for use in diagnostic procedures such as electrocardiography (ECG) analysis, as they eliminate several of the drawbacks associated with the conventional ‘wet’ electrodes currently used for physiological signal recording. To be commercially successful in such a competitive market, it is essential that dry electrodes are manufacturable in high volumes and at low cost. In addition, the topographical nature of these emerging devices means that electrode performance is likely to be highly dependent on the quality of the skin-electrode contact. This paper presents a low-cost, wafer-level micromoulding technology for the fabrication of polymeric ECG electrodes that use microneedle structures to make a direct electrical contact to the body. The double-sided moulding process can be used to eliminate post-process via creation and wafer dicing steps. In addition, measurement techniques have been developed to characterize the skin-electrode contact force. We perform the first analysis of signal-to-noise ratio dependency on contact force, and show that although microneedle-based electrodes can outperform conventional gel electrodes, the quality of ECG recordings is significantly dependent on temporal and mechanical aspects of the skin-electrode interface.

  2. A surface energy analysis of mucoadhesion: contact angle measurements on polycarbophil and pig intestinal mucosa in physiologically relevant fluids.

    Science.gov (United States)

    Lehr, C M; Bouwstra, J A; Boddé, H E; Junginger, H E

    1992-01-01

    The possible role of surface energy thermodynamics in mucoadhesion was investigated with Polycarbophil and pig intestinal mucosa. In separate experiments, the surface energy parameters of the substrate (mucosa) and the adhesive (polymer film) were determined by contact angle measurements on captive air/octane bubbles in three physiologically relevant test fluids (isotonic saline, artificial gastric fluid, and artificial intestinal fluid). Whereas the swollen Polycarbophil films were relatively hydrophilic as indicated by small water contact angles (22, 23, and 16 degrees), the water contact angles measured on mucosal tissue were significantly larger (61, 48, and 57 degrees). Hence, mucus was found to possess an appreciable hydrophobicity. The measured adhesive performance (force of detachment) between Polycarbophil and pig small intestinal mucosa was highest in nonbuffered saline medium, intermediate in gastric fluid, and minimal in intestinal fluid. In agreement with this trend, the mismatch in surface polarities between substrate and adhesive, calculated from the contact angle data, increased in the same order.

  3. Energy conserving schemes for the simulation of musical instrument contact dynamics

    CERN Document Server

    Chatziioannou, Vasileios

    2015-01-01

    Collisions are an innate part of the function of many musical instruments. Due to the nonlinear nature of contact forces, special care has to be taken in the construction of numerical schemes for simulation and sound synthesis. Finite difference schemes and other time-stepping algorithms used for musical instrument modelling purposes are normally arrived at by discretising a Newtonian description of the system. However because impact forces are non-analytic functions of the phase space variables, algorithm stability can rarely be established this way. This paper presents a systematic approach to deriving energy conserving schemes for frictionless impact modelling. The proposed numerical formulations follow from discretising Hamilton's equations of motion, generally leading to an implicit system of nonlinear equations that can be solved with Newton's method. The approach is first outlined for point mass collisions and then extended to distributed settings, such as vibrating strings and beams colliding with rig...

  4. Dynamics of spider glue adhesion: effect of surface energy and contact area

    Science.gov (United States)

    Amarpuri, Gaurav; Chen, Yizhou; Blackledge, Todd; Dhinojwala, Ali

    Spider glue is a unique biological adhesive which is humidity responsive such that the adhesion continues to increase upto 100% relative humidity (RH) for some species. This is unlike synthetic adhesives that significantly drop in adhesion with an increase in humidity. However, most of adhesion data reported in literature have used clean hydrophilic glass substrate, unlike the hydrophobic, and charged insect cuticle surface that adheres to spider glue in nature. Previously, we have reported that the spider glue viscosity changes over five orders of magnitude with humidity. Here, we vary the surface energy and surface charge of the substrate to test the change in Larnioides cornutus spider glue adhesion with humidity. We find that an increase in both surface energy and surface charge density increases the droplet spreading and there exists an optimum droplet contact area where adhesion is maximized. Moreover, spider glue droplets act as reusable adhesive for low energy hydrophobic surface at the optimum humidity. These results explain why certain prey are caught more efficiently by spiders in their habitat. The mechanism by which spider species tune its glue adhesion for local prey capture can inspire new generation smart adhesives.

  5. Social contacts and Ecstasy offers: findings of a population-based study.

    Science.gov (United States)

    Smirnov, Andrew; Najman, Jake M; Legosz, Margot; Wells, Helene; Kemp, Robert

    2013-01-01

    Ecstasy (MDMA) use is relatively common among young adults in many developed countries. However, little is known about how young non-users are first introduced to Ecstasy, including the relative contribution of peer networks and individual risk factors. We assess the role of social contact with Ecstasy-using peers in regard to young adults' exposure to offers of Ecstasy, using data from the Natural History Study, a population-based study conducted in Australia. Population screening of young adults (19- to 23-year-olds) identified a sample of young Ecstasy users (N = 315) and a comparison group of Ecstasy-naïve participants (N = 199). Two outcomes are considered: being exposed to any Ecstasy offers and being exposed to > 3 offers. Extensive social contact with Ecstasy users was defined as knowing > 10 Ecstasy users. Of the Ecstasy-naïve young adults, > 40% had ever received Ecstasy offers. Extensive social contact with Ecstasy users independently predicted exposure to multiple (> 3) Ecstasy offers for Ecstasy-naïve young adults. These findings indicate that Ecstasy offers are widespread among users and non-users of Ecstasy. For non-users, exposure to Ecstasy offers occurs through social contact with drug-using peers independently of individual risk factors. The pervasiveness of Ecstasy offers suggests that universal education concerning Ecstasy use is required.

  6. Layered Double Hydroxide Nanoplatelets with Excellent Tribological Properties under High Contact Pressure as Water-Based Lubricant Additives.

    Science.gov (United States)

    Wang, Hongdong; Liu, Yuhong; Chen, Zhe; Wu, Bibo; Xu, Sailong; Luo, Jianbin

    2016-01-01

    High efficient and sustainable utilization of water-based lubricant is essential for saving energy. In this paper, a kind of layered double hydroxide (LDH) nanoplatelets is synthesized and well dispersed in water due to the surface modification with oleylamine. The excellent tribological properties of the oleylamine-modified Ni-Al LDH (NiAl-LDH/OAm) nanoplatelets as water-based lubricant additives are evaluated by the tribological tests in an aqueous environment. The modified LDH nanoplatelets are found to not only reduce the friction but also enhance the wear resistance, compared with the water-based cutting fluid and lubricants containing other particle additives. By adding 0.5 wt% LDH nanoplatelets, under 1.5 GPa initial contact pressure, the friction coefficient, scar diameter, depth and width of the wear track dramatically decrease by 83.1%, 43.2%, 88.5% and 59.5%, respectively. It is considered that the sufficiently small size and the excellent dispersion of NiAl-LDH/OAm nanoplatelets in water are the key factors, so as to make them enter the contact area, form a lubricating film and prevent direct collision of asperity peaks. Our investigations demonstrate that the LDH nanoplatelet as a water-based lubricant additive has a great potential value in industrial application. PMID:26951794

  7. Layered Double Hydroxide Nanoplatelets with Excellent Tribological Properties under High Contact Pressure as Water-Based Lubricant Additives

    Science.gov (United States)

    Wang, Hongdong; Liu, Yuhong; Chen, Zhe; Wu, Bibo; Xu, Sailong; Luo, Jianbin

    2016-03-01

    High efficient and sustainable utilization of water-based lubricant is essential for saving energy. In this paper, a kind of layered double hydroxide (LDH) nanoplatelets is synthesized and well dispersed in water due to the surface modification with oleylamine. The excellent tribological properties of the oleylamine-modified Ni-Al LDH (NiAl-LDH/OAm) nanoplatelets as water-based lubricant additives are evaluated by the tribological tests in an aqueous environment. The modified LDH nanoplatelets are found to not only reduce the friction but also enhance the wear resistance, compared with the water-based cutting fluid and lubricants containing other particle additives. By adding 0.5 wt% LDH nanoplatelets, under 1.5 GPa initial contact pressure, the friction coefficient, scar diameter, depth and width of the wear track dramatically decrease by 83.1%, 43.2%, 88.5% and 59.5%, respectively. It is considered that the sufficiently small size and the excellent dispersion of NiAl-LDH/OAm nanoplatelets in water are the key factors, so as to make them enter the contact area, form a lubricating film and prevent direct collision of asperity peaks. Our investigations demonstrate that the LDH nanoplatelet as a water-based lubricant additive has a great potential value in industrial application.

  8. Deep-Hole Inner Diameter Measuring System Based on Non-contact Capacitance Sensor

    Institute of Scientific and Technical Information of China (English)

    于永新; 张恒; 王宗超; 常以哲

    2010-01-01

    A precise aperture measuring system of small deep holes with capacitance sensors is presented. Based on the working principle of non-contact capacitance sensors, influence of the edge effect of gauge head is studied, and one capacitance sensor for measuring the aperture of the small blind holes or through holes is introduced. The system is composed of one positioning device, one aperture measuring capacitance sensor, one measuring circuit, and software. This system employs visual CCD and two-dimensional mic...

  9. A highly sensitive flexible strain sensor based on the contact resistance change of carbon nanotube bundles

    Science.gov (United States)

    Song, Youngsup; Lee, Jae-Ik; Pyo, Soonjae; Eun, Youngkee; Choi, Jungwook; Kim, Jongbaeg

    2016-05-01

    A novel carbon nanotube (CNT)-based flexible strain sensor with the highest gauge factor of 4739 is presented. CNT-to-CNT contacts are fabricated on a pair of silicon electrodes fixed on a PDMS specimen for both flexibility and electrical connection. The strain is detected by the resistance change between facing CNT bundles. The proposed approach could be applied for diverse applications with a high gauge factor.

  10. Neonatal Non-contact Respiratory Monitoring based on Real-Time Infrared Thermography

    OpenAIRE

    Abbas Abbas K; Heimann Konrad; Jergus Katrin; Orlikowsky Thorsten; Leonhardt Steffen

    2011-01-01

    Abstract Background Monitoring of vital parameters is an important topic in neonatal daily care. Progress in computational intelligence and medical sensors has facilitated the development of smart bedside monitors that can integrate multiple parameters into a single monitoring system. This paper describes non-contact monitoring of neonatal vital signals based on infrared thermography as a new biomedical engineering application. One signal of clinical interest is the spontaneous respiration ra...

  11. Resonant tunneling diodes as energy-selective contacts used in hot-carrier solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Yasuhiko, E-mail: takeda@mosk.tytlabs.co.jp; Sugimoto, Noriaki [Toyota Central Research and Development Laboratories, Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 (Japan); Ichiki, Akihisa [Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Kusano, Yuya [Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Toyota Motor Corp., 1200 Mishuku, Susono, Shizuoka 410-1193 (Japan); Motohiro, Tomoyoshi [Toyota Central Research and Development Laboratories, Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 (Japan); Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan)

    2015-09-28

    Among the four features unique to hot-carrier solar cells (HC-SCs): (i) carrier thermalization time and (ii) carrier equilibration time in the absorber, (iii) energy-selection width and (iv) conductance of the energy-selective contacts (ESCs), requisites of (i)-(iii) for high conversion efficiency have been clarified. We have tackled the remaining issues related to (iv) in the present study. The detailed balance model of HC-SC operation has been improved to involve a finite value of the ESC conductance to find the required values, which in turn has been revealed to be feasible using resonant tunneling diodes (RTDs) consisting of semiconductor quantum dots (QDs) and quantum wells (QWs) by means of a formulation to calculate the conductance of the QD- and QW-RTDs derived using the rigorous solutions of the effective-mass Hamiltonians. Thus, all of the four requisites unique to HC-SCs to achieve high conversion efficiency have been elucidated, and the two requisites related to the ESCs can be fulfilled using the QD- and QW-RTDs.

  12. Resonant tunneling diodes as energy-selective contacts used in hot-carrier solar cells

    Science.gov (United States)

    Takeda, Yasuhiko; Ichiki, Akihisa; Kusano, Yuya; Sugimoto, Noriaki; Motohiro, Tomoyoshi

    2015-09-01

    Among the four features unique to hot-carrier solar cells (HC-SCs): (i) carrier thermalization time and (ii) carrier equilibration time in the absorber, (iii) energy-selection width and (iv) conductance of the energy-selective contacts (ESCs), requisites of (i)-(iii) for high conversion efficiency have been clarified. We have tackled the remaining issues related to (iv) in the present study. The detailed balance model of HC-SC operation has been improved to involve a finite value of the ESC conductance to find the required values, which in turn has been revealed to be feasible using resonant tunneling diodes (RTDs) consisting of semiconductor quantum dots (QDs) and quantum wells (QWs) by means of a formulation to calculate the conductance of the QD- and QW-RTDs derived using the rigorous solutions of the effective-mass Hamiltonians. Thus, all of the four requisites unique to HC-SCs to achieve high conversion efficiency have been elucidated, and the two requisites related to the ESCs can be fulfilled using the QD- and QW-RTDs.

  13. Resonant tunneling diodes as energy-selective contacts used in hot-carrier solar cells

    International Nuclear Information System (INIS)

    Among the four features unique to hot-carrier solar cells (HC-SCs): (i) carrier thermalization time and (ii) carrier equilibration time in the absorber, (iii) energy-selection width and (iv) conductance of the energy-selective contacts (ESCs), requisites of (i)-(iii) for high conversion efficiency have been clarified. We have tackled the remaining issues related to (iv) in the present study. The detailed balance model of HC-SC operation has been improved to involve a finite value of the ESC conductance to find the required values, which in turn has been revealed to be feasible using resonant tunneling diodes (RTDs) consisting of semiconductor quantum dots (QDs) and quantum wells (QWs) by means of a formulation to calculate the conductance of the QD- and QW-RTDs derived using the rigorous solutions of the effective-mass Hamiltonians. Thus, all of the four requisites unique to HC-SCs to achieve high conversion efficiency have been elucidated, and the two requisites related to the ESCs can be fulfilled using the QD- and QW-RTDs

  14. Effect of chemical heterogeneity of biodegradable polymers on surface energy: A static contact angle analysis of polyester model films.

    Science.gov (United States)

    Belibel, R; Avramoglou, T; Garcia, A; Barbaud, C; Mora, L

    2016-02-01

    Biodegradable and bioassimilable poly((R,S)-3,3 dimethylmalic acid) (PDMMLA) derivatives were synthesized and characterized in order to develop a new coating for coronary endoprosthesis enabling the reduction of restenosis. The PDMMLA was chemically modified to form different custom groups in its side chain. Three side groups were chosen: the hexyl group for its hydrophobic nature, the carboxylic acid and alcohol groups for their acid and neutral hydrophilic character, respectively. The sessile drop method was applied to characterize the wettability of biodegradable polymer film coatings. Surface energy and components were calculated. The van Oss approach helped reach not only the dispersive and polar acid-base components of surface energy but also acid and basic components. Surface topography was quantified by atomic force microscopy (AFM) and subnanometer average values of roughness (Ra) were obtained for all the analyzed surfaces. Thus, roughness was considered to have a negligible effect on wettability measurements. In contrast, heterogeneous surfaces had to be corrected by the Cassie-Baxter equation for copolymers (10/90, 20/80 and 30/70). The impact of this correction was quantified for all the wettability parameters. Very high relative corrections (%) were found, reaching 100% for energies and 30% for contact angles. PMID:26652458

  15. Oxygen-aromatic contacts in intra-strand base pairs: analysis of high-resolution DNA crystal structures and quantum chemical calculations.

    Science.gov (United States)

    Jain, Alok; Krishna Deepak, R N V; Sankararamakrishnan, Ramasubbu

    2014-07-01

    Three-dimensional structures of biomolecules are stabilized by a large number of non-covalent interactions and some of them such as van der Waals, electrostatic and hydrogen bond interactions are well characterized. Delocalized π-electron clouds of aromatic residues are known to be involved in cation-π, CH-π, OH-π and π-π interactions. In proteins, many examples have been found in which the backbone carbonyl oxygen of one residue makes close contact with the aromatic center of aromatic residues. Quantum chemical calculations suggest that such contacts may provide stability to the protein secondary structures. In this study, we have systematically analyzed the experimentally determined high-resolution DNA crystal structures and identified 91 examples in which the aromatic center of one base is in close contact (interactions between the bases in base pairs with oxygen-aromatic contacts are energetically favorable. Decomposition of interaction energies indicates that dispersion forces are the major cause for energetically stable interaction in these base pairs. We speculate that oxygen-aromatic contacts in intra-strand base pairs in a DNA structure may have biological significance. PMID:24816369

  16. Probing the nature and resistance of the molecule-electrode contact in SAM-based junctions

    Science.gov (United States)

    Suchand Sangeeth, C. S.; Wan, Albert; Nijhuis, Christian A.

    2015-07-01

    It is challenging to quantify the contact resistance and to determine the nature of the molecule-electrode contacts in molecular two-terminal junctions. Here we show that potentiodynamic and temperature dependent impedance measurements give insights into the nature of the SAM-electrode interface and other bottlenecks of charge transport (the capacitance of the SAM (CSAM) and the resistance of the SAM (RSAM)), unlike DC methods, independently of each other. We found that the resistance of the top-electrode-SAM contact for junctions with the form of AgTS-SCn//GaOx/EGaIn with n = 10, 12, 14, 16 or 18 is bias and temperature independent and hence Ohmic (non-rectifying) in nature, and is orders of magnitude smaller than RSAM. The CSAM and RSAM are independent of the temperature, indicating that the mechanism of charge transport in these SAM-based junctions is coherent tunneling and the charge carrier trapping at the interfaces is negligible.It is challenging to quantify the contact resistance and to determine the nature of the molecule-electrode contacts in molecular two-terminal junctions. Here we show that potentiodynamic and temperature dependent impedance measurements give insights into the nature of the SAM-electrode interface and other bottlenecks of charge transport (the capacitance of the SAM (CSAM) and the resistance of the SAM (RSAM)), unlike DC methods, independently of each other. We found that the resistance of the top-electrode-SAM contact for junctions with the form of AgTS-SCn//GaOx/EGaIn with n = 10, 12, 14, 16 or 18 is bias and temperature independent and hence Ohmic (non-rectifying) in nature, and is orders of magnitude smaller than RSAM. The CSAM and RSAM are independent of the temperature, indicating that the mechanism of charge transport in these SAM-based junctions is coherent tunneling and the charge carrier trapping at the interfaces is negligible. Electronic supplementary information (ESI) available: Detailed experimental procedure, Nyquist

  17. Non-Contact Plant Growth Measurement Method and System Based on Ubiquitous Sensor Network Technologies

    Directory of Open Access Journals (Sweden)

    Intae Ryoo

    2011-04-01

    Full Text Available This paper proposes a non-contact plant growth measurement system using infrared sensors based on the ubiquitous sensor network (USN technology. The proposed system measures plant growth parameters such as the stem radius of plants using real-time non-contact methods, and generates diameter, cross-sectional area and thickening form of plant stems using this measured data. Non-contact sensors have been used not to cause any damage to plants during measurement of the growth parameters. Once the growth parameters are measured, they are transmitted to a remote server using the sensor network technology and analyzed in the application program server. The analyzed data are then provided for administrators and a group of interested users. The proposed plant growth measurement system has been designed and implemented using fixed-type and rotary-type infrared sensor based measurement methods and devices. Finally, the system performance is compared and verified with the measurement data that have been obtained by practical field experiments.

  18. Individual-based approach to epidemic processes on arbitrary dynamic contact networks.

    Science.gov (United States)

    Rocha, Luis E C; Masuda, Naoki

    2016-01-01

    The dynamics of contact networks and epidemics of infectious diseases often occur on comparable time scales. Ignoring one of these time scales may provide an incomplete understanding of the population dynamics of the infection process. We develop an individual-based approximation for the susceptible-infected-recovered epidemic model applicable to arbitrary dynamic networks. Our framework provides, at the individual-level, the probability flow over time associated with the infection dynamics. This computationally efficient framework discards the correlation between the states of different nodes, yet provides accurate results in approximating direct numerical simulations. It naturally captures the temporal heterogeneities and correlations of contact sequences, fundamental ingredients regulating the timing and size of an epidemic outbreak, and the number of secondary infections. The high accuracy of our approximation further allows us to detect the index individual of an epidemic outbreak in real-life network data. PMID:27562273

  19. PSD Camera Based Position and Posture Control of Redundant Robot Considering Contact Motion

    Science.gov (United States)

    Oda, Naoki; Kotani, Kentaro

    The paper describes a position and posture controller design based on the absolute position by external PSD vision sensor for redundant robot manipulator. The redundancy enables a potential capability to avoid obstacle while continuing given end-effector jobs under contact with middle link of manipulator. Under contact motion, the deformation due to joint torsion obtained by comparing internal and external position sensor, is actively suppressed by internal/external position hybrid controller. The selection matrix of hybrid loop is given by the function of the deformation. And the detected deformation is also utilized in the compliant motion controller for passive obstacle avoidance. The validity of the proposed method is verified by several experimental results of 3link planar redundant manipulator.

  20. Morse potential-based model for contacting composite rough surfaces: Application to self-assembled monolayer junctions

    Science.gov (United States)

    Sierra-Suarez, Jonatan A.; Majumdar, Shubhaditya; McGaughey, Alan J. H.; Malen, Jonathan A.; Higgs, C. Fred

    2016-04-01

    This work formulates a rough surface contact model that accounts for adhesion through a Morse potential and plasticity through the Kogut-Etsion finite element-based approximation. Compared to the commonly used Lennard-Jones (LJ) potential, the Morse potential provides a more accurate and generalized description for modeling covalent materials and surface interactions. An extension of this contact model to describe composite layered surfaces is presented and implemented to study a self-assembled monolayer (SAM) grown on a gold substrate placed in contact with a second gold substrate. Based on a comparison with prior experimental measurements of the thermal conductance of this SAM junction [Majumdar et al., Nano Lett. 15, 2985-2991 (2015)], the more general Morse potential-based contact model provides a better prediction of the percentage contact area than an equivalent LJ potential-based model.

  1. Neonatal non-contact respiratory monitoring based on real-time infrared thermography

    Directory of Open Access Journals (Sweden)

    Abbas Abbas K

    2011-10-01

    Full Text Available Abstract Background Monitoring of vital parameters is an important topic in neonatal daily care. Progress in computational intelligence and medical sensors has facilitated the development of smart bedside monitors that can integrate multiple parameters into a single monitoring system. This paper describes non-contact monitoring of neonatal vital signals based on infrared thermography as a new biomedical engineering application. One signal of clinical interest is the spontaneous respiration rate of the neonate. It will be shown that the respiration rate of neonates can be monitored based on analysis of the anterior naris (nostrils temperature profile associated with the inspiration and expiration phases successively. Objective The aim of this study is to develop and investigate a new non-contact respiration monitoring modality for neonatal intensive care unit (NICU using infrared thermography imaging. This development includes subsequent image processing (region of interest (ROI detection and optimization. Moreover, it includes further optimization of this non-contact respiration monitoring to be considered as physiological measurement inside NICU wards. Results Continuous wavelet transformation based on Debauches wavelet function was applied to detect the breathing signal within an image stream. Respiration was successfully monitored based on a 0.3°C to 0.5°C temperature difference between the inspiration and expiration phases. Conclusions Although this method has been applied to adults before, this is the first time it was used in a newborn infant population inside the neonatal intensive care unit (NICU. The promising results suggest to include this technology into advanced NICU monitors.

  2. Modular correction method of bending elastic modulus based on sliding behavior of contact point

    International Nuclear Information System (INIS)

    During the three-point bending test, the sliding behavior of the contact point between the specimen and supports was observed, the sliding behavior was verified to affect the measurements of both deflection and span length, which directly affect the calculation of the bending elastic modulus. Based on the Hertz formula to calculate the elastic contact deformation and the theoretical calculation of the sliding behavior of the contact point, a theoretical model to precisely describe the deflection and span length as a function of bending load was established. Moreover, a modular correction method of bending elastic modulus was proposed, via the comparison between the corrected elastic modulus of three materials (H63 copper–zinc alloy, AZ31B magnesium alloy and 2026 aluminum alloy) and the standard modulus obtained from standard uniaxial tensile tests, the universal feasibility of the proposed correction method was verified. Also, the ratio of corrected to raw elastic modulus presented a monotonically decreasing tendency as the raw elastic modulus of materials increased. (technical note)

  3. Effective contact resistance of zinc-tin oxide-based thin film transistors.

    Science.gov (United States)

    Kang, Youjin; Han, Dongsuk; Park, Jaehyung; Shin, Sora; Choi, Duckkyun; Park, Jongwan

    2014-11-01

    We investigated different source/drain (S/D) electrode materials in thin-film transistors (TFTs) based on amorphous zinc-tin oxide (ZTO) semiconductors. The transfer length, channel conductance, and effective contact resistance between the S/D electrodes and the a-ZTO channel layer were examined. Total ON resistance (R(T)), transfer length (L(T)) and effective contact resistance (R(c-eff)) were extracted by the well-known transmission-line method (TLM) using a series of TFTs with different channel lengths. When the width of ZTO channel layer was fixed as 50 μm, the lengths were varying from 10 to 50 μm. The channel layer and S/D electrode were defined by lift-off process and for the S/D electrodes, indium-tin oxide (ITO), Cu, and Mo were used. The resistivity and work function values of electrode materials were considered when selected as candidates for S/D electrodes of ZTO-TFTs. The results showed that the ZTO-TFTs with Mo S/D electrodes had the lowest effective contact resistance indicating that ZTO-TFTs with Mo electrodes have better electrical performance compared to others. PMID:25958489

  4. Tribology and energy efficiency: from molecules to lubricated contacts to complete machines.

    Science.gov (United States)

    Taylor, Robert Ian

    2012-01-01

    The impact of lubricants on energy efficiency is considered. Molecular details of base oils used in lubricants can have a great impact on the lubricant's physical properties which will affect the energy efficiency performance of a lubricant. In addition, molecular details of lubricant additives can result in significant differences in measured friction coefficients for machine elements operating in the mixed/boundary lubrication regime. In single machine elements, these differences will result in lower friction losses, and for complete systems (such as cars, trucks, hydraulic circuits, industrial gearboxes etc.) lower fuel consumption or lower electricity consumption can result.

  5. Contact dermatitis

    Science.gov (United States)

    Dermatitis - contact; Allergic dermatitis; Dermatitis - allergic; Irritant contact dermatitis; Skin rash - contact dermatitis ... There are 2 types of contact dermatitis. Irritant dermatitis: This ... can be by contact with acids, alkaline materials such as soaps ...

  6. Multicenter Patch Testing With a Resol Resin Based on Phenol and Formaldehyde Within the International Contact Dermatitis Research Group

    DEFF Research Database (Denmark)

    Isaksson, M.; Ale, I.; Andersen, Klaus Ejner;

    2015-01-01

    Background Contact allergy to phenol-formaldehyde resins (PFRs) based on phenol and formaldehyde is not detected by a p-tertiary-butylphenol-formaldehyde resin included in most baseline patch test series. Objective The aims of this study were to investigate the contact allergy rate to PFR-2...

  7. CONSRANK: a server for the analysis, comparison and ranking of docking models based on inter-residue contacts

    KAUST Repository

    Chermak, Edrisse

    2014-12-21

    Summary: Herein, we present CONSRANK, a web tool for analyzing, comparing and ranking protein–protein and protein–nucleic acid docking models, based on the conservation of inter-residue contacts and its visualization in 2D and 3D interactive contact maps.

  8. An elastography method based on the scanning contact resonance of a piezoelectric cantilever

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Ji; Li, Faxin, E-mail: lifaxin@pku.edu.cn [State Key Lab for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871, China and HEDPS, Center for Applied Physics and Technologies, Peking University, Beijing 100871 (China)

    2013-12-15

    Purpose: Most tissues may become significantly stiffer than their normal states when there are lesions inside. The tissue's modulus can then act as an identification parameter for clinic diagnosis of tumors or fibrosis, which leads to elastography. This study introduces a novel elastography method that can be used for modulus imaging of superficial organs. Methods: This method is based on the scanning contact-resonance of a unimorph piezoelectric cantilever. The cantilever vibrates in its bending mode with the tip pressed tightly on the sample. The contact resonance frequency of the cantilever-sample system is tracked at each scanning point, from which the sample's modulus can be derived based on a beam dynamic model and a contact mechanics model. Scanning is performed by a three-dimensional motorized stage and the whole system is controlled by a homemade software program based on LabVIEW. Results: Testing onin vitro beef tissues indicates that the fat and the muscle can be easily distinguished using this system, and the accuracy of the modulus measurement can be comparable with that of nanoindentation. Imaging on homemade gelatin phantoms shows that the depth information of the abnormalities can be qualitatively obtained by varying the pressing force. The detection limit of this elastography method is specially examined both experimentally and numerically. Results show that it can detect the typical lesions in superficial organs with the depth of several centimeters. The lateral resolution of this elastography method/system is better than 0.5 mm, and could be further enhanced by using more scanning points. Conclusions: The proposed elastography system can be regarded as a sensitive palpation robot, which may be very promising in early diagnosis of tumors in superficial organs such as breast and thyroid.

  9. Contact-less magneto-elastic torsional sensor based on phase-shift measurements

    International Nuclear Information System (INIS)

    We report on the development of a contact-less measurement technique for torsional shear stress τ in ferromagnetic axles or hollow shafts, based on the magneto-elastic effect. In general, two different measuring principles for ferromagnetic materials can be realized, based on: the evaluation of the change of magnetic polarization influenced by shear stress ΔJ(τ) or the change of the magnetic susceptibility ΔχA(τ). The comprehension of the magnetic polarization or the magnetic susceptibility in a sensor concept requires an external magnetic field. Alternating magnetic fields were used as shear stress can disturb not only the amplitude but also the phase distribution of the applied magnetic field. As a result of a torsional moment acting on an axle or hollow shaft, an angle of twist η appears, which is constant over the length of the twisted object. This angle of twist can be understood as a shift of infinitesimal thin cross-sections in which the whole length of the axle is separated. Besides the macroscopic deformation effect, shear forces also affect the Weiss-domains in the micro-scale of the ferromagnetic material. The effects in the micro-scale are the base of the magneto-elastic effect. The combination of the deformation effect in the macro-scale and the deformation of the Weiss-domains in the micro-scale leads to a sophisticated measurement principle for torsional stress in axles or hollow shafts. Magneto-sensitive detectors along or around the measurement object open up the possibility for a contact-less detection of torsional stress in ferromagnetic materials. Besides a strong measuring signal, free from electromagnetic interference, the introduced contact-less measurement principle offers different advantages, like independence from compression strength, nominal tensile stress, impact load, ferromagnetic hysteresis effects and independence of the temperature-dependent electrical conductivity of the axle or hollow shaft. The characteristics of such a

  10. Microstructure and properties of silver based cadmium free electrical contact materials

    Directory of Open Access Journals (Sweden)

    Talijan N.

    2007-01-01

    Full Text Available The presented work covers part of experimental results of simultaneous study of microstructure, density, hardness and electrical conductivity of sintered electrical contact materials based of Ag- SnO2 with 8, 10 and 12 mass% SnO2. The mentioned characteristics were analyzed in the function of different sintering regimes and after additional mechanical treatment (forging and rolling. The influence of small addition of In2O3 (2.9 mass% on the increase of dispersion of main oxide SnO2 in Ag matrix is observed and presented also.

  11. Non-contact angle measurement based on parallel multiplex laser feedback interferometry

    International Nuclear Information System (INIS)

    We present a novel precise angle measurement scheme based on parallel multiplex laser feedback interferometry (PLFI), which outputs two parallel laser beams and thus their displacement difference reflects the angle variation of the target. Due to its ultrahigh sensitivity to the feedback light, PLFI realizes the direct non-contact measurement of non-cooperative targets. Experimental results show that PLFI has an accuracy of 8″ within a range of 1400″. The yaw of a guide is also measured and the experimental results agree with those of the dual-frequency laser interferometer Agilent 5529A. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  12. A simple process based on NH2- and CH3-terminated monolayers for low contact resistance and adherent Au electrode in bottom-contact OTFTs

    Science.gov (United States)

    Abdur, Rahim; Lim, Jeongeun; Jeong, Kyunghoon; Rahman, Mohammad Arifur; Kim, Jiyoung; Lee, Jaegab

    2016-03-01

    An efficient process for the low contact resistance and adherent source/drain Au electrode in bottom-contact organic thin film transistors (OTFTs) was developed. This was achieved by using two different surface-functional groups of self-assembled monolayers, 3-aminopropyltriethoxysilane (APS), and octadecyltrichlorosilane (OTS), combined with atmospheric-pressure (AP) plasma treatment. Prior to the deposition of Au electrode, the aminoterminated monolayer self-assembles on SiO2 dielectrics, enhancing the adhesion of Au electrode as a result of the acid-base interaction of Au with the amino-terminal groups. AP plasma treatment of the patterned Au electrode on the APS-coated surface activates the entire surface to form an OTS monolayer, allowing the formation of a high quality pentacene layer on both the electrode and active region by evaporation. In addition, negligible damage by AP plasma was observed for the device performance. The fabricated OTFTs based on the two monolayers by AP plasma treatment showed the mobility of 0.23 cm2/Vs, contact resistance of 29 kΩ-cm, threshold voltage of -1.63 V, and on/off ratio of 9.8 × 105, demonstrating the application of the simple process for robust and high-performance OTFTs. [Figure not available: see fulltext.

  13. Contact-enhanced transparent silver nanowire network for all solution-based top-contact metal-oxide thin-film transistors.

    Science.gov (United States)

    Kim, Yong-Hoon; Kim, Tae-Hyoung; Lee, Yeji; Kim, Jong-Woong; Kim, Jaekyun; Park, Sung Kyu

    2014-11-01

    In this paper, we investigate contact-enhanced transparent silver nanowire (Ag NW) network for solution-processed metal-oxide thin-film transistors (TFTs). Mechanical roll pressing was applied to a bar-coated Ag NW film to enhance the inter-nanowire connectivity. As a result, the sheet resistance of the Ag NW film was decreased from 119.5 ψ/square to 92.4 ψ/square, and more stable and enhanced TFT characteristics were achieved when the roll-pressed Ag NW was employed as source/drain electrodes. In addition, a non-acidic wet etching method was developed to pattern the Ag NW electrodes to construct top-contact geometry indium-gallium-zinc oxide TFTs. From the results, it is believed that the mechanical roll pressing and non-acidic wet etching method may be utilized in realizing all solution-based transparent metal-oxide TFTs. PMID:25958491

  14. DTN中一种基于接触时间的休眠机制%Sleep Scheme Based on Contact Time in DTN

    Institute of Scientific and Technical Information of China (English)

    付凯; 夏靖波; 尹波

    2013-01-01

    Considering the problem that energy supplies are limited in DTN,a sleep scheme based on contact time was proposed. Nodes carry out adaptive strategy to adjust wait time and sleep time according to former contact time, and reduce the probability of missing communication opportunities in sleep period. Simulation results indicate that Epidemic algorithm with SSCT can reduce network overhead and energy consumption based on high message delivery ratio, and SSCT has better performance on multi-copy routing algorithms compared with First Contact algorithm.%针对容迟/容断网络(DTN)中能量供应受限的问题,提出一种基于接触时间的休眠机制SSCT(Sleep Scheme based on Contact Time).节点依据历史接触时间自适应调整等待时间和休眠时间,从而降低休眠期间错失通信机会的概率.仿真实验表明,添加SSCT的Epidemic算法能够在保证消息交付率的基础上降低网络开销和能耗.相比First Contact算法,SSCT对多副本路由算法的性能提升更加明显.

  15. A theory of molecular transistor based on the two-center electrochemical bridged tunneling contact

    International Nuclear Information System (INIS)

    Graphical abstract: The transistor-like behavior of the two-center electrochemical.bridged tunneling contact in the case of the large Debye screening. Gate voltage: (1) -0.075 V; (2) -0.025 V; (3) 0; (4) 0.025 V; (5) 0.075 V. Highlights: → The tunneling contact based on the two-center redox molecule operates as transistor. → A theory takes into account both Coulomb blockade and Debye screening effects. → We obtain new expressions for the tunnel current in the non-adiabatic limit. → We reveal the regions where both strong rectification and amplification take place. → The transistor-like current/voltage characteristics are calculated. - Abstract: It is shown that the two-center bridged tunneling contact in the serial configuration based on the donor-acceptor single redox molecule immersed in the electrolyte solution at the ambient conditions (i.e., room temperature and condensed matter environment) demonstrates pronounced transistor-like features for certain sets of the physical parameters of the system. Electrons at the redox centers of the bridge molecule are coupled strongly to the classical phonon modes of the condensed matter environment and Debye screening of the electric field is taken into account. The case of the non-adiabatic tunneling of electrons between the centers and between the centers and electrodes is considered and the limit of the infinite Coulomb repulsion between electrons occupying the same center is used. The regions of the physical parameters where both strong rectification and strong amplification (over three orders of magnitude) take place for all positive (or negative) values of the bias voltage are revealed and the transistor-like current/bias voltage characteristics are calculated.

  16. The Contact State Monitoring for Seal End Faces Based on Acoustic Emission Detection

    Directory of Open Access Journals (Sweden)

    Xiaohui Li

    2016-01-01

    Full Text Available Monitoring the contact state of seal end faces would help the early warning of the seal failure. In the acoustic emission (AE detection for mechanical seal, the main difficulty is to reduce the background noise and to classify the dispersed features. To solve these problems and achieve higher detection rates, a new approach based on genetic particle filter with autoregression (AR-GPF and hypersphere support vector machine (HSSVM is presented. First, AR model is used to build the dynamic state space (DSS of the AE signal, and GPF is used for signal filtering. Then, multiple features are extracted, and a classification model based on HSSVM is constructed for state recognition. In this approach, AR-GPF is an excellent time-domain method for noise reduction, and HSSVM has advantage on those dispersed features. Finally experimental data shows that the proposed method can effectively detect the contact state of the seal end faces and has higher accuracy rates than some other existing methods.

  17. Educational Intervention for an Evidence-Based Nursing Practice of Skin-to-Skin Contact at Birth.

    Science.gov (United States)

    Turenne, Jeanne Pigeon; Héon, Marjolaine; Aita, Marilyn; Faessler, Joanne; Doddridge, Chantal

    2016-01-01

    This article presents the development and evaluation of an educational intervention aiming at an evidence-based practice of skin-to-skin contact at birth among nurses of a maternity care unit. Based on the Iowa Model of Evidence-Based Practice to Promote Quality Care, four educational sessions were developed according to an active-learning pedagogy. Even if the nurses' practice did not fully meet the recommendations for skin-to-skin contact, a pre- and postintervention evaluation showed some positive results, such as a longer duration of skin-to-skin contact immediately after birth, delivery of some routine care directly on mothers' chest, and improved parent education. The educational intervention seems to have enacted some evidence-based nursing practice changes regarding skin-to-skin contact at birth. PMID:27445449

  18. Effect of contact interface configuration on electronic transport in (C20)2-based molecular junctions

    International Nuclear Information System (INIS)

    Using first-principles calculations, we study the electronic transport properties in Au-(C20)2-Au molecular junctions with different contact interface configurations: point contact and bond contact. We observe that the transmission through the bond contact is considerably higher than that of point contact. Furthermore, the I–V characteristics are rather different. For the bond contact, we get a metallic behavior followed by a varistor-type behavior. While as for the point contact, the current increases very slowly in a nonlinear way and is one order of magnitude smaller than that of bond contact. We attribute these obvious differences to the distinct contact configurations. -- Highlights: ► The I–V properties of (C20)2 molecular devices are affected by contact configuration. ► As for the bond contact, metallic behavior in the low bias is observed. ► Varistor-type behavior and nonlinear I–V characteristic in the high bias are found. ► As for the point contact, the Landauer conductance greatly decreases. ► The current is one order of magnitude smaller than that of bond contact.

  19. Bilateral Teleoperation Method Using an Autonomous Control Based on Information on Contact Environment

    Science.gov (United States)

    Taguchi, Keiichi; Ohnishi, Kouhei

    In procedures that involve remote control, such as remote surgery, it is necessary to operate a robot in a remote location in a sensitive environment; the treatment of internal organs is an example of such a procedure. In this paper, we propose a method for autonomous hazard avoidance control that is based on information on the contact environment. The proposed method involves the use of bilateral control. During safe operations, systems are controlled by bilateral control. During dangerous operations, a slave system is controlled autonomously so as to avoid dangerous operations. In order to determine the degree of operation risk, fuzzy set theory is applied to the force exerted on the environment. Further, variable compliance control based on the force exerted on the environment is utilized to avoid the risk. The effectiveness of the proposed method is confirmed by experimental results.

  20. The mechanisms of cracks formation of silver-based contact materials under arc and making pressure

    Institute of Scientific and Technical Information of China (English)

    GUO Feng-yi(郭凤仪); CHEN Zhong-hua(陈忠华); ZHANG Ling-ling(张玲玲); ZHANG Ji-hua(张继华); FW Leuschner

    2004-01-01

    The arc erosion experiments on five kinds of silver-based contact materials, AgZnO (10), AgSnO2 (8.5) In2O3 (4), AgCdO (12), AgNi(10), AgWC(12)C(3) were carried out according to different breaking times, breaking currents, and making pressures. Then based on the theoretical analysis and the photographs taken by scanning electronic microscope with EDAX analyzer, the crack morphology was studied scientifically. Three types of cracks, which are cavity cracks, grain boundaries (or phase boundaries) slipping cracks, and thermal stress cracks, were put forward under arc and making pressure through establishing their physical models and discussing their formation mechanisms.

  1. Kuerschner's energy manual. Political contacts at national, state and European level; Kuerschners Handbuch Energie. Politikkontakte Bund, Land, Europa

    Energy Technology Data Exchange (ETDEWEB)

    Holzapfel, Andreas (ed.)

    2011-07-01

    The manual is in three sections: 1. Parliaments and governments, survey and organization; 2. Biographic section, with 453 biography; 3. Index of names. The first section informs on the organizational structure of parliaments and governments. The subject of energy is discussed three times, i.e. in 'Economics', 'Environment', and 'Research'. For each parliament, the members of the energy policy TCs are listed, followed by names and contact addresses of the senior officials and departments with contact data, both on a national, state, and European scale. The second section contains the biographies of energy policy experts of the German parliament and government, the sixteen land parliaments and governments, and the European Commissions. As the subject of energy is highly interdisciplinary, the authors selected the energy policy committees of the German parliament and state parliaments. The biographies of the committee members are presented in the text.

  2. Development and testing of new biologically-based polymers as advanced biocompatible contact lenses

    Energy Technology Data Exchange (ETDEWEB)

    Bertozzi, Carolyn R.

    2000-06-01

    Nature has evolved complex and elegant materials well suited to fulfill a myriad of functions. Lubricants, structural scaffolds and protective sheaths can all be found in nature, and these provide a rich source of inspiration for the rational design of materials for biomedical applications. Many biological materials are based in some fashion on hydrogels, the crosslinked polymers that absorb and hold water. Biological hydrogels contribute to processes as diverse as mineral nucleation during bone growth and protection and hydration of the cell surface. The carbohydrate layer that coats all living cells, often referred to as the glycocalyx, has hydrogel-like properties that keep cell surfaces well hydrated, segregated from neighboring cells, and resistant to non-specific protein deposition. With the molecular details of cell surface carbohydrates now in hand, adaptation of these structural motifs to synthetic materials is an appealing strategy for improving biocompatibility. The goal of this collaborative project between Prof. Bertozzi's research group, the Center for Advanced Materials at Lawrence Berkeley National Laboratory and Sunsoft Corporation was the design, synthesis and characterization of novel hydrogel polymers for improved soft contact lens materials. Our efforts were motivated by the urgent need for improved materials that allow extended wear, and essential feature for those whose occupation requires the use of contact lenses rather than traditional spectacles. Our strategy was to transplant the chemical features of cell surface molecules into contact lens materials so that they more closely resemble the tissue in which they reside. Specifically, we integrated carbohydrate molecules similar to those found on cell surfaces, and sulfoxide materials inspired by the properties of the carbohydrates, into hydrogels composed of biocompatible and manufacturable substrates. The new materials were characterized with respect to surface and bulk hydrophilicity

  3. Dynamics of vehicle-pavement coupled system based on a revised flexible roller contact tire model

    Institute of Scientific and Technical Information of China (English)

    YANG ShaoPu; LI ShaoHua; LU YongJie

    2009-01-01

    A revised flexible roller contact tire model (RFRC tire model) is proposed, which considers not only the geometric and flexible filtering effect, but also tire damping and pavement displacement. A vehi-cle-pavement coupled system is modeled as a two DOF oscillator moving along a simply supported beam on a linear viscoelastic foundation. By using the Galerkin's and Direct Integral method, dynamical responses of the vehicle-pavement coupled system are obtained based on the RFRC tire model and the traditional single point contact tire model (SPC tire model). The simulation results are compared with test data and the validity of the proposed RFRC tire model is verified. Differences between the two models are also investigated. It is found that the dynamical behaviors for both models agree with each other quite well when road surface roughness is a long harmonic wave. On the other hand, they are different under short harmonic wave or impulse road excitation. Thus the RFRC tire model should be used to compute the tire force and investigate dynamical responses of vehicle and pavement.

  4. A review of non-contact, low-cost physiological information measurement based on photoplethysmographic imaging.

    Science.gov (United States)

    Liu, He; Wang, Yadong; Wang, Lei

    2012-01-01

    In recent decades, there has been increasing interest in low-cost, non-contact and pervasive methods for measuring physiological information, such as heart rate (HR), respiratory rate, heart rate variability (HRV) and oxyhemoglobin saturation. The conventional methods including wet adhesive Ag/AgCl electrodes for HR and HRV, the capnograph device for respiratory status and pulse oximetry for oxyhemoglobin saturation provide excellent signals but are expensive, troublesome and inconvenient. A method to monitor physiological information based on photoplethysmographic imaging offers a new means for health monitoring. Blood volume can be indirectly assessed in terms of blood velocity, blood flow rate and blood pressure, which, in turn, can reflect changes in physiological parameters. Changes in blood volume can be determined from the spectra of light reflected from or transmitted through body tissues. Images of an area of the skin surface are consecutively captured with the color camera of a computer or smartphone and, by processing and analyzing the light signals, physiological information such as HR, respiratory rate, HRV and oxyhemoglobin saturation can be acquired. In this paper, we review the latest developments in using photoplethysmographic imaging for non-contact health monitoring and discuss the challenges and future directions for this field. PMID:23366332

  5. Dynamics of vehicle-pavement coupled system based on a revised flexible roller contact tire model

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A revised flexible roller contact tire model (RFRC tire model) is proposed, which considers not only the geometric and flexible filtering effect, but also tire damping and pavement displacement. A vehi- cle-pavement coupled system is modeled as a two DOF oscillator moving along a simply supported beam on a linear viscoelastic foundation. By using the Galerkin’s and Direct Integral method, dynamical responses of the vehicle-pavement coupled system are obtained based on the RFRC tire model and the traditional single point contact tire model (SPC tire model). The simulation results are compared with test data and the validity of the proposed RFRC tire model is verified. Differences between the two models are also investigated. It is found that the dynamical behaviors for both models agree with each other quite well when road surface roughness is a long harmonic wave. On the other hand, they are different under short harmonic wave or impulse road excitation. Thus the RFRC tire model should be used to compute the tire force and investigate dynamical responses of vehicle and pavement.

  6. Novel silicone hydrogel based on PDMS and PEGMA for contact lens application.

    Science.gov (United States)

    Lin, Chien-Hong; Yeh, Yi-Hsing; Lin, Wen-Ching; Yang, Ming-Chien

    2014-11-01

    A silicone-based hydrogel was synthesized from poly(dimethylsiloxane) dialkanol (PDMS), isophorone diisocyanate (IPDI), 2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) methacrylate (PEGMA). The hydrophilicity of the resulting block copolymer was adjustable by manipulating the ratio of PDMS and PEGMA. The results showed that higher PEGMA content led to a lower water contact angle, higher water content, lower elastic modulus and higher glucose permeability. At a PEGMA content of 20%, the protein adsorption decreased to 23% and 18% for lysozyme and human serum albumin (HSA), respectively, of those of the control (PDMS-PU). This indicated that the PDMS-PU-PEGMA hydrogels exhibited an ability to resist protein adsorption. The oxygen permeability (Dk) was 92 barrers for the hydrogel with 20% PEGMA. Furthermore, these hydrogels were non-cytotoxic according to an in vitro L929 fibroblast assay. Overall, the results demonstrated that the PDMS-PU-PEGMA hydrogels exhibited not only relatively high oxygen permeability and relative optical transparency, but also hydrophilicity and anti-protein adsorption; therefore, they would be applicable as a contact lens material. Furthermore, this study demonstrated a new approach to controlling the performance of silicone hydrogels. PMID:25465755

  7. Microstructure of V-based ohmic contacts to AlGaN/GaN heterostructures at a reduced annealing temperature

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, A., E-mail: alexander.schmid@physik.tu-freiberg.de; Schroeter, Ch.; Otto, R.; Heitmann, J. [Institute of Applied Physics, TU Bergakademie Freiberg, 09599 Freiberg (Germany); Schuster, M. [Namlab gGmbH, 01187 Dresden (Germany); Klemm, V.; Rafaja, D. [Institute of Materials Science, TU Bergakademie Freiberg, 09599 Freiberg (Germany)

    2015-02-02

    Ohmic contacts with V/Al/Ni/Au and V/Ni/Au metalization schemes were deposited on AlGaN/GaN heterostructures. The dependence of the specific contact resistance on the annealing conditions and the V:Al thickness ratio was shown. For an optimized electrode stack, a low specific contact resistance of 8.9 × 10{sup −6} Ω cm{sup 2} was achieved at an annealing temperature of 650 °C. Compared to the conventional Ti/Al/Ni/Au contact, this is a reduction of 150 K. The microstructure and contact formation at the AlGaN/metal interface were investigated by transmission electron microscopy including high-resolution micrographs and energy dispersive X-ray analysis. It was shown that for low-resistive contacts, the resistivity of the metalization has to be taken into account. The V:Al thickness ratio has an impact on the formation of different intermetallic phases and thus is crucial for establishing ohmic contacts at reduced annealing temperatures.

  8. Endoluminal non-contact soft tissue ablation using fiber-based Er:YAG laser delivery

    Science.gov (United States)

    Kundrat, Dennis; Fuchs, Alexander; Schoob, Andreas; Kahrs, Lüder A.; Ortmaier, Tobias

    2016-03-01

    The introduction of Er:YAG lasers for soft and hard tissue ablation has proven promising results over the last decades due to strong absorption at 2.94 μm wavelength by water molecules. An extension to endoluminal applications demands laser delivery without mirror arms due to dimensional constraints. Therefore, fiber-based solutions are advanced to provide exible access while keeping space requirements to a minimum. Conventional fiber-based treatments aim at laser-tissue interactions in contact mode. However, this procedure is associated with disadvantages such as advancing decrease in power delivery due to particle coverage of the fiber tip, tissue carbonization, and obstructed observation of the ablation progress. The objective of this work is to overcome aforementioned limitations with a customized fiber-based module for non-contact robot-assisted endoluminal surgery and its associated experimental evaluation. Up to the authors knowledge, this approach has not been presented in the context of laser surgery at 2.94 μm wavelength. The preliminary system design is composed of a 3D Er:YAG laser processing unit enabling automatic laser to fiber coupling, a GeO2 solid core fiber, and a customized module combining collimation and focusing unit (focal length of 20 mm, outer diameter of 8 mm). The performance is evaluated with studies on tissue substitutes (agar-agar) as well as porcine samples that are analysed by optical coherence tomography measurements. Cuts (depths up to 3mm) with minimal carbonization have been achieved under adequate moistening and sample movement (1.5mms-1). Furthermore, an early cadaver study is presented. Future work aims at module miniaturization and integration into an endoluminal robot for scanning and focus adaptation.

  9. Volumetric quantification of bone-implant contact using micro-computed tomography analysis based on region-based segmentation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sung Won; Lee, Woo Jin; Choi, Soon Chul; Lee, Sam Sun; Heo, Min Suk; Huh, Kyung Hoe; Kim, Tae Il; Yi, Won Ji [Dental Research Institute, School of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    2015-03-15

    We have developed a new method of segmenting the areas of absorbable implants and bone using region-based segmentation of micro-computed tomography (micro-CT) images, which allowed us to quantify volumetric bone-implant contact (VBIC) and volumetric absorption (VA). The simple threshold technique generally used in micro-CT analysis cannot be used to segment the areas of absorbable implants and bone. Instead, a region-based segmentation method, a region-labeling method, and subsequent morphological operations were successively applied to micro-CT images. The three-dimensional VBIC and VA of the absorbable implant were then calculated over the entire volume of the implant. Two-dimensional (2D) bone-implant contact (BIC) and bone area (BA) were also measured based on the conventional histomorphometric method. VA and VBIC increased significantly with as the healing period increased (p<0.05). VBIC values were significantly correlated with VA values (p<0.05) and with 2D BIC values (p<0.05). It is possible to quantify VBIC and VA for absorbable implants using micro-CT analysis using a region-based segmentation method.

  10. Electrically detected nuclear magnetic resonance in GaAs/AlGaAs-based quantum point contacts

    Science.gov (United States)

    Keane, Zachary; Godfrey, Matthew; Burke, Adam; Chen, Jason; Fricke, Sebastian; Klochan, Oleh; Micolich, Adam; Beere, Harvey; Ritchie, Dave; Trunov, Kirill; Reuter, Dirk; Wieck, Andreas; Hamilton, Alex

    2011-03-01

    Nuclear magnetic resonance (NMR) is a well-known technique with widespread applications in physics, chemistry and medicine. Conventional NMR studies use inductive coils to detect the magnetic field produced by precessing nuclear spins; this approach requires on the order of 1012 spins for detection. Recently, resistive detection of NMR through the hyperfine interaction has been demonstrated with electrons in mesoscopic 2- and 1-dimensional devices based on high-quality GaAs/AlGaAs heterostructures. These studies are typically sensitive to 108 spins, enabling NMR on much smaller sample volumes. Holes are predicted to have much weaker nuclear spin coupling than electrons, which could be relevant to the emerging fields of spintronics and quantum information processing. We present a preliminary comparison between the magnitude of the NMR signal in electron and hole quantum point contacts.

  11. Wholly smoothing cutter orientations for five-axis NC machining based on cutter contact point mesh

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Cutting forces with respect to different cutter orientations are analyzed for five-axis NC machining of a ball-end cutter.A measure is then defined to quantify the effects of cutter orientation variation.According to the measure,a novel model and algorithm are proposed to wholly optimize cutter orientations based on a cutter contact(CC) point mesh.The method has two advantages.One is that the cutter orientation smoothnesses along the feed direction and pick-feed direction are both wholly optimized.The other is that only the accessibility cones of mesh points are required to compute and the computation efficiency is improved.These advantages are shown by simulating the machining efficiency,the stability of feed velocities and the smoothness of cutting force.A computational example and a cutting experiment are finally given to illustrate the validity of the proposed method.

  12. Nanolithography based contacting method for electrical measurements on single template synthesized nanowires

    DEFF Research Database (Denmark)

    Fusil, S.; Piraux, L.; Mátéfi-Tempfli, Stefan;

    2005-01-01

    A reliable method enabling electrical measurements on single nanowires prepared by electrodeposition in an alumina template is described. This technique is based on electrically controlled nanoindentation of a thin insulating resist deposited on the top face of the template filled by the nanowires....... We show that this method is very flexible, allowing us to electrically address single nanowires of controlled length down to 100 nm and of desired composition. Using this approach, current densities as large as 10 A cm were successfully injected through a point contact on a single magnetic...... multilayered nanowire. This demonstrates that the technique is very promising for the exploration of electrical spin injection in magnetic nanostructures. © 2005 IOP Publishing Ltd....

  13. Real time optimization of solar powered direct contact membrane distillation based on multivariable extremum seeking

    KAUST Repository

    Karam, Ayman M.

    2015-09-21

    This paper presents a real time optimization scheme for a solar powered direct contact membrane distillation (DCMD) water desalination system. The sun and weather conditions vary and are inconsistent throughout the day. Therefore, the solar powered DCMD feed inlet temperature is never constant, which influences the distilled water flux. The problem of DCMD process optimization has not been studied enough. In this work, the response of the process under various feed inlet temperatures is investigated, which demonstrates the need for an optimal controller. To address this issue, we propose a multivariable Newton-based extremum seeking controller which optimizes the inlet feed and permeate mass flow rates as the feed inlet temperature varies. Results are presented and discussed for a realistic temperature profile.

  14. ContactLess Integrated Photonic Probe for light monitoring in InP-based devices

    CERN Document Server

    Melati, Daniele; Grillanda, Stefano; Ferrari, Giorgio; Morichetti, Francesco; Sampietro, Marco; Melloni, Andrea

    2014-01-01

    The increasing complexity of photonic integrated circuits requires the possibility to monitor the state of the circuit in order to stabilize the working point against environmental fluctuations or to perform reliable reconfiguration procedures. Although InP technologies can naturally integrate high-quality photodiodes, their use as tap monitors necessarily affects the circuit response and is restricted to few units per chip. They are hence unsuited for very large circuits, where transparent power monitors become key components. In this paper we present the implementation of a ContactLess Integrated Photonic Probe (CLIPP) realizing a non invasive integrated light monitor on InP-based devices. We describe an innovative vertical scheme of the CLIPP monitor which exploits the back side of the chip as a common electrode, thus enabling a reduction of the device footprint and a simplification of the electrical connectivity. We characterize the response of the CLIPP and demonstrate its functionality as power monitor....

  15. Acoustic detection of North Atlantic right whale contact calls using spectrogram-based statistics.

    Science.gov (United States)

    Urazghildiiev, Ildar R; Clark, Christopher W

    2007-08-01

    This paper considers the problem of detection of contact calls produced by the critically endangered North Atlantic right whale, Eubalaena glacialis. To reduce computational time, the class of acceptable detectors is constrained by the detectors implemented as a bank of two-dimensional linear FIR filters and using the data spectrogram as the input. The closed form representations for the detectors are derived and the detection performance is compared with that of the generalized likelihood ratio test (GLRT) detector. The test results demonstrate that in the presence of impulsive noise, the spectrogram-based detector using the French hat wavelet as the filter kernel outperforms the GLRT detector and decreases computational time by a factor of 6. PMID:17672627

  16. The Sentiment Trend Analysis of Twitter Based on Set Pair Contact Degree

    Directory of Open Access Journals (Sweden)

    Chunying Zhang

    2013-01-01

    Full Text Available Sentiment trend of twitter users have a great influence on their friends and the crowd listened. This paper directs at the user sentiment state of twitter, the unique medium, and applies set pair analysis method for trend analysis. First, we begin with set pair contact degree, then based on set pair affective computing model to make comparison with the size relationship of same degree, difference degree, opposition degree of the emotion, to build the user sentiment trend analysis model; Secondly, we analyze the influence for the user's own sentiment trend when the value changed of difference coefficient ; thirdly, after analyze to obtain one user's sentiment orientation threshold as prerequisite for user behavior prediction. Finally, setting an example to calculate the sentiment trend of one twitter, then to get the conclusion is that the analysis of user emotion from a three-dimensional angle is more realistic than the single angle.

  17. Population-based analysis of health care contacts among suicide decedents: identifying opportunities for more targeted suicide prevention strategies.

    Science.gov (United States)

    Schaffer, Ayal; Sinyor, Mark; Kurdyak, Paul; Vigod, Simone; Sareen, Jitender; Reis, Catherine; Green, Diane; Bolton, James; Rhodes, Anne; Grigoriadis, Sophie; Cairney, John; Cheung, Amy

    2016-06-01

    The objective of this study was to detail the nature and correlates of mental health and non-mental health care contacts prior to suicide death. We conducted a systematic extraction of data from records at the Office of the Chief Coroner of Ontario of each person who died by suicide in the city of Toronto from 1998 to 2011. Data on 2,835 suicide deaths were linked with provincial health administrative data to identify health care contacts during the 12 months prior to suicide. Sub-populations of suicide decedents based on the presence and type of mental health care contact were described and compared across socio-demographic, clinical and suicide-specific variables. Time periods from last mental health contact to date of death were calculated and a Cox proportional hazards model examined covariates. Among suicide decedents, 91.7% had some type of past-year health care contact prior to death, 66.4% had a mental health care contact, and 25.3% had only non-mental health contacts. The most common type of mental health contact was an outpatient primary care visit (54.0%), followed by an outpatient psychiatric visit (39.8%), an emergency department visit (31.1%), and a psychiatric hospitalization (21.0%). The median time from last mental health contact to death was 18 days (interquartile range 5-63). Mental health contact was significantly associated with female gender, age 25-64, absence of a psychosocial stressor, diagnosis of schizophrenia or bipolar disorder, past suicide attempt, self-poisoning method and absence of a suicide note. Significant differences between sub-populations of suicide decedents based on the presence and nature of their health care contacts suggest the need for targeting of community and clinical-based suicide prevention strategies. The predominance of ambulatory mental health care contacts, often close to the time of death, reinforce the importance of concentrating efforts on embedding risk assessment and care pathways into all routine primary

  18. Causal Analysis of the Inadvertent Contact with an Uncontrolled Electrical Hazardous Energy Source (120 Volts AC)

    Energy Technology Data Exchange (ETDEWEB)

    David E. James; Dennis E. Raunig; Sean S. Cunningham

    2014-10-01

    On September 25, 2013, a Health Physics Technician (HPT) was performing preparations to support a pneumatic transfer from the HFEF Decon Cell to the Room 130 Glovebox in HFEF, per HFEF OI 3165 section 3.5, Field Preparations. This activity involves an HPT setting up and climbing a portable ladder to remove the 14-C meter probe from above ball valve HBV-7. The HPT source checks the meter and probe and then replaces the probe above HBV-7, which is located above Hood ID# 130 HP. At approximately 13:20, while reaching past the HBV-7 valve position indicator switches in an attempt to place the 14-C meter probe in the desired location, the HPT’s left forearm came in contact with one of the three sets of exposed terminals on the valve position indication switches for HBV 7. This resulted in the HPT receiving an electrical shock from a 120 Volt AC source. Upon moving the arm, following the electrical shock, the HPT noticed two exposed electrical connections on a switch. The HPT then notified the HFEF HPT Supervisor, who in turn notified the MFC Radiological Controls Manager and HFEF Operations Manager of the situation. Work was stopped in the area and the hazard was roped off and posted to prevent access to the hazard. The HPT was escorted by the HPT Supervisor to the MFC Dispensary and then preceded to CFA medical for further evaluation. The individual was evaluated and released without any medical restrictions. Causal Factor (Root Cause) A3B3C01/A5B2C08: - Knowledge based error/Attention was given to wrong issues - Written Communication content LTA, Incomplete/situation not covered The Causal Factor (root cause) was attention being given to the wrong issues during the creation, reviews, verifications, and actual performance of HFEF OI-3165, which covers the need to perform the weekly source check and ensure placement of the probe prior to performing a “rabbit” transfer. This resulted in the hazard not being identified and mitigated in the procedure. Work activities

  19. Contact-flatted measurement of eye stiffness based on force-displacement relationship

    Science.gov (United States)

    Zhang, Jin; Ma, Jianguo; Zhang, Xueyong

    2011-12-01

    This paper presents a noninvasive approach in vivo measurement of eye stiffness based on a force-displacement relationship, which is based on a new contact-probe method of simultaneously measuring the static force and displacement. First, a simple spherical eye model is introduced for deriving analytical eye stiffness when a static force is applied to an eye. Next, a measurement system for simultaneously measuring force and displacement when a probe is pressed onto the eye is presented. Static eye stiffness is defined which based on the measured force-displacement relationship. A photoelectric probe transducer acts as displacement detector. A 16-bit single-chip microprocessor with E2PROM in the electronic circuit played the role of a nucleus, which stored the program instructions and the interrelated data. Laboratory experiments were carried out on a simulated eyeball connected to a hydraulic manometer to obtain intraocular pressure at different levels. The experimental results show that the measured eye stiffness nicely matches the analytical result.

  20. Efficient Regular Perovskite Solar Cells Based on Pristine [70]Fullerene as Electron-Selective Contact.

    Science.gov (United States)

    Collavini, Silvia; Kosta, Ivet; Völker, Sebastian F; Cabanero, German; Grande, Hans J; Tena-Zaera, Ramón; Delgado, Juan Luis

    2016-06-01

    [70]Fullerene is presented as an efficient alternative electron-selective contact (ESC) for regular-architecture perovskite solar cells (PSCs). A smart and simple, well-described solution processing protocol for the preparation of [70]- and [60]fullerene-based solar cells, namely the fullerene saturation approach (FSA), allowed us to obtain similar power conversion efficiencies for both fullerene materials (i.e., 10.4 and 11.4 % for [70]- and [60]fullerene-based devices, respectively). Importantly, despite the low electron mobility and significant visible-light absorption of [70]fullerene, the presented protocol allows the employment of [70]fullerene as an efficient ESC. The [70]fullerene film thickness and its solubility in the perovskite processing solutions are crucial parameters, which can be controlled by the use of this simple solution processing protocol. The damage to the [70]fullerene film through dissolution during the perovskite deposition is avoided through the saturation of the perovskite processing solution with [70]fullerene. Additionally, this fullerene-saturation strategy improves the performance of the perovskite film significantly and enhances the power conversion efficiency of solar cells based on different ESCs (i.e., [60]fullerene, [70]fullerene, and TiO2 ). Therefore, this universal solution processing protocol widens the opportunities for the further development of PSCs. PMID:26991031

  1. Internal Energy Losses and Contact Duration About a Circular Plate Colliding to a Half-Plane Target

    Institute of Scientific and Technical Information of China (English)

    L(U) Zhong-jie

    2009-01-01

    Collisions between multibody systems are irreversible processes which cause loss of internal energy by a stress wave that propagates in the impacting bodies away from the region of impact. A coefficient of restitution relating to approach velocity is introduced to denote the losses of translational kinetic energy. A parameter β involved in internal energy losses has been obtained to calculate the coefficient of restitution. As a result, the internal energy losses caused by elastic stress waves and the contact duration in metals can be calculated numerically for the collision between circular cylinder and half plane. The metals include aluminum alloys, steel-mild 1020, steel-stainless austenitic 304, tungsten alloys, copper alloys, nickel alloys and titanium alloys. By introducing a coefficient of velocity-frequency, an exponential aggression equation related the normalized oscillating frequency and normalized approach velocity has been obtained by the numerical method.

  2. Faults and energy losses in electric contacts; Fallas y perdidas de energia en contactos electricos

    Energy Technology Data Exchange (ETDEWEB)

    Bratu Serban, Neagu; Campero Littlewood, Eduardo [Universidad Autonoma Metropolitana, Mexico, D. F. (Mexico)

    1993-12-31

    In this paper a brief description is made of the behavior of the electric contacts and the elements that affect in the heat release during its operation. The mathematical expressions describing this phenomenon are presented. The losses that can be produced at the contacts are evaluated and the graphs, where the behavior of these different operating conditions can be seen, are included. [Espanol] En este articulo se hace una breve descripcion del comportamiento de los contactos electricos y de los elementos que influyen en la generacion de calor durante su operacion. Se presentan las expresiones con las que se describe matematicamente este fenomeno. Se evaluan las perdidas que pueden llegar a tenerse en los contactos y se incluyen graficas donde puede verse el comportamiento de estos en diferentes condiciones de operacion.

  3. A smart interfacing method based on domain/boundary decomposition for efficient thermo-elasto-viscoplastic damage and contact analysis

    International Nuclear Information System (INIS)

    A smart interfacing method based on domain/boundary decomposition is presented for the non-linear analysis of thermo-elastoviscoplastic damage and contact. The smart interfacing method provides adaptive reinterfacing of the subdomains and the interface as a result of changes in the viscoplasticity and damage level. Since the whole domain is divided into subdomains, interface, and contact interfaces, non-linear analyses of the problems can be localized within a few subdomains and on the contact interfaces. For the continuity constraints on the interface and the contact interfaces, a penalty method is applied to the variational formulations and finite element approximations. By applying suitable solution algorithms and adopting the smart interfacing method, the computational efficiency can be considerably improved. The important features of the proposed method were also evaluated through numerical experiments

  4. Adaptive method for real-time gait phase detection based on ground contact forces.

    Science.gov (United States)

    Yu, Lie; Zheng, Jianbin; Wang, Yang; Song, Zhengge; Zhan, Enqi

    2015-01-01

    A novel method is presented to detect real-time gait phases based on ground contact forces (GCFs) measured by force sensitive resistors (FSRs). The traditional threshold method (TM) sets a threshold to divide the GCFs into on-ground and off-ground statuses. However, TM is neither an adaptive nor real-time method. The threshold setting is based on body weight or the maximum and minimum GCFs in the gait cycles, resulting in different thresholds needed for different walking conditions. Additionally, the maximum and minimum GCFs are only obtainable after data processing. Therefore, this paper proposes a proportion method (PM) that calculates the sums and proportions of GCFs wherein the GCFs are obtained from FSRs. A gait analysis is then implemented by the proposed gait phase detection algorithm (GPDA). Finally, the PM reliability is determined by comparing the detection results between PM and TM. Experimental results demonstrate that the proposed PM is highly reliable in all walking conditions. In addition, PM could be utilized to analyze gait phases in real time. Finally, PM exhibits strong adaptability to different walking conditions.

  5. On the Challenges of Reducing Contact Resistances in Thermoelectric Generators Based on Half-Heusler Alloys

    DEFF Research Database (Denmark)

    Pham, Hoang Ngan; Van Nong, Ngo; Le, Thanh Hung;

    2016-01-01

    -type, respectively. Using this method, the quality of the HH–electrode contacts is improved due to their low electrical contact resistance and less reaction– diffusion layer. The microstructure and chemical composition of the joints were examined using a scanning electron microscope equipped with energydispersive x...

  6. Evaporation Erosion During the Relay Contact Breaking Process Based on a Simplified Arc Model

    Institute of Scientific and Technical Information of China (English)

    CUI Xinglei; ZHOU Xue; ZHAI Guofu; PENG Xiyuan

    2016-01-01

    Evaporation erosion of the contacts is one of the fundamental failure mechanisms for relays.In this paper,the evaporation erosion characteristics are investigated for the copper contact pair breaking a resistive direct current (dc) 30 V/10 A circuit in the air.Molten pool simulation of thc contacts is coupled with the gas dynamics to cMculate the evaporation rate.A simplified arc model is constructed to obtain the contact voltage and current variations with time for the prediction of the current density and the heat flux distributions flowing from the arc into the contacts.The evaporation rate and mass variations with time during the breaking process are presented.Experiments are carried out to verify the simulation results.

  7. Non-contact pumping of light emitters via non-radiative energy transfer

    Science.gov (United States)

    Klimov, Victor I.; Achermann, Marc

    2010-01-05

    A light emitting device is disclosed including a primary light source having a defined emission photon energy output, and, a light emitting material situated near to said primary light source, said light emitting material having an absorption onset equal to or less in photon energy than the emission photon energy output of the primary light source whereby non-radiative energy transfer from said primary light source to said light emitting material can occur yielding light emission from said light emitting material.

  8. A Model for Contact Binary Systems

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A model for contact binary systems is presented, which incorporates the following special features: a) The energy exchange between the components is based on the understanding that the energy exchange is due to the release of potential, kinetic and thermal energies of the exchanged mass. b) A special form of mass and angular momentum loss occurring in contact binaries is losses via the outer Lagrangian point. c) The effects of spin, orbital rotation and tidal action on the stellar structure as well as the effect of meridian circulation on the mixing of the chemical elements are considered. d) The model is valid not only for low-mass contact binaries but also for high-mass contact binaries. For illustration, we used the model to trace the evolution of a massive binary system consisting of one 12M⊙ and one 5M⊙ star. The result shows that the start and end of the contact stage fall within the semi-detached phase during which the primary continually transfers mass to the secondary. The time span of the contact stage is short and the mass transfer rate is very large. Therefore, the contact stage can be regarded as a special part of the semi-detached phase with a large mass transfer rate. Both mass loss through the outer Lagrangian point and oscillation between contact and semi-contact states can occur during the contact phase, and the effective temperatures of the primary and the secondary are almost equal.

  9. Language Contact.

    Science.gov (United States)

    Nelde, Peter Hans

    1995-01-01

    Examines the phenomenon of language contact and recent trends in linguistic contact research, which focuses on language use, language users, and language spheres. Also discusses the role of linguistic and cultural conflicts in language contact situations. (13 references) (MDM)

  10. Corporate Consumer Contact API

    Data.gov (United States)

    General Services Administration — The data in the Corporate Consumer Contact API is based on the content you can find in the Corporate Consumer Contact listing in the Consumer Action Handbook (PDF)....

  11. Development of separation techniques for a direct contact thermal energy storage system

    Energy Technology Data Exchange (ETDEWEB)

    Min, T.C. [North Carolina A& T State Univ., Greensboro, NC (United States); Tomlinson, J.J. [Oak Ridge National Lab., TN (United States)

    1989-03-01

    In direct contact ice-making processes, the refrigerant will pick up water vapor through direct percolation and oil from the compressor. The purpose of this project is to investigate methods for separating water vapor and oil from a mixture to complete a refrigeration cycle. In this paper, we report critical review on two separation techniques. From a literature search, we have identified a third technique; and plan to evaluate this method by bench-scale experiments. A recommendation for future work is included.

  12. An efficient formulation based on the Lagrangian method for contact-impact analysis of flexible multi-body system

    Science.gov (United States)

    Chen, Peng; Liu, Jin-Yang; Hong, Jia-Zhen

    2016-04-01

    In this paper, an efficient formulation based on the Lagrangian method is presented to investigate the contact-impact problems of flexible multi-body systems. Generally, the penalty method and the Hertz contact law are the most commonly used methods in engineering applications. However, these methods are highly dependent on various non-physical parameters, which have great effects on the simulation results. Moreover, a tremendous number of degrees of freedom in the contact-impact problems will influence the numerical efficiency significantly. With the consideration of these two problems, a formulation combining the component mode synthesis method and the Lagrangian method is presented to investigate the contact-impact problems in flexible multi-body system numerically. Meanwhile, the finite element meshing laws of the contact bodies will be studied preliminarily. A numerical example with experimental verification will certify the reliability of the presented formulation in contact-impact analysis. Furthermore, a series of numerical investigations explain how great the influence of the finite element meshing has on the simulation results. Finally the limitations of the element size in different regions are summarized to satisfy both the accuracy and efficiency.

  13. The Yield of Community-Based “Retrospective” Tuberculosis Contact Investigation in a High Burden Setting in Ethiopia

    Science.gov (United States)

    2016-01-01

    Objective To determine the yield and determinants of retrospective TB contact investigation in selected zones in Ethiopia. Materials and Methods This was a community-based cross-sectional study conducted during June-October 2014.Trained lay providers performed symptom screening for close contacts of index cases with all types of TB registered for anti-TB treatment within the last three years. We used logistic regression to determine factors associated with TB diagnosis among the contacts. Results Of 272,441 close contacts of 47, 021 index cases screened, 13,886 and 2, 091 had presumptive and active TB respectively. The yield of active TB was thus 768/100, 000, contributing 25.4% of the 7,954 TB cases reported from the study zones over the study period. The yield was highest among workplace contacts (12,650/100, 000). Active TB was twice more likely among contacts whose index cases had been registered for TB treatment within the last 12 months compared with those who had been registered 24 or more months earlier (adjusted odds ratio, AOR: 1.77 95% CI 1.42–2.21). Sex or clinical type of TB in index cases was not associated with the yield. Smear negative (SS-) index cases (AOR: 1.74 955 CI 1.13–2.68), having index cases who registered for treatment within risk groups not addressed through currently recommended screening approaches. PMID:27483160

  14. Non-contact detection of cardiac rate based on visible light imaging device

    Science.gov (United States)

    Zhu, Huishi; Zhao, Yuejin; Dong, Liquan

    2012-10-01

    We have developed a non-contact method to detect human cardiac rate at a distance. This detection is based on the general lighting condition. Using the video signal of human face region captured by webcam, we acquire the cardiac rate based on the PhotoPlethysmoGraphy theory. In this paper, the cardiac rate detecting method is mainly in view of the blood's different absorptivities of the lights various wavelengths. Firstly, we discompose the video signal into RGB three color signal channels and choose the face region as region of interest to take average gray value. Then, we draw three gray-mean curves on each color channel with time as variable. When the imaging device has good fidelity of color, the green channel signal shows the PhotoPlethysmoGraphy information most clearly. But the red and blue channel signals can provide more other physiological information on the account of their light absorptive characteristics of blood. We divide red channel signal by green channel signal to acquire the pulse wave. With the passband from 0.67Hz to 3Hz as a filter of the pulse wave signal and the frequency spectrum superimposed algorithm, we design frequency extracted algorithm to achieve the cardiac rate. Finally, we experiment with 30 volunteers, containing different genders and different ages. The results of the experiments are all relatively agreeable. The difference is about 2bmp. Through the experiment, we deduce that the PhotoPlethysmoGraphy theory based on visible light can also be used to detect other physiological information.

  15. Influence of temporal aspects and age-correlations on the process of opinion formation based on Polish contact survey

    CERN Document Server

    Grabowski, Andrzej

    2016-01-01

    On the basis of the experimental data concerning interactions between humans the process of Ising-based model of opinion formation in a social network was investigated. In the paper the data concerning human social activity, i.e. frequency and duration time of interpersonal interactions as well as age correlations - homophily are presented in comparison to base line homogeneous, static and uniform mixing. It is known from previous studies that number of contact and average age of nearest neighbors are highly correlated with age of an individual. Such real, assortative patterns usually speed up processes (like epidemic spread) on the networks, but here it only plays a role for small social temperature values (by reducing `freezing by heating' effect). A real structure of contacts affects processes in many various studies in different way, however here it causes stronger (dynamic) and smoother (durations) susceptibility on external field. Moreover, our research shows that the cross interactions between contact ...

  16. Hospital contacts for chronic diseases among danish seafarers and fishermen: a population-based cohort study

    DEFF Research Database (Denmark)

    Kaerlev, Linda; Dahl, Søren; Nielsen, Per Sabro;

    2007-01-01

    OBJECTIVES: Seafarers' and fishermen's working conditions may impact on their lifestyle and health. Standardized hospital contact ratios (SHCRs) were compared in two time periods and the relative risks of hospital contact as a function of employment time were estimated. METHODS: Cohorts of all Da......-related selection into the trades or a healthy worker effect. CONCLUSIONS: Danish seafarers, especially short-term employees, had an elevated risk of hospitalization for lifestyle-related diseases....

  17. Greenlandic adoptees' psychiatric inpatient contact. A comparative register-based study

    DEFF Research Database (Denmark)

    Laubjerg, Merete; Petersson, Birgit

    2010-01-01

    .4 (CI 95% 1.8 - 6.6). The most frequent diagnosis is ‘Inherent or acquired brain suffering'. The findings open up possibilities for new hypotheses as to reasons for adoptees' reverse health outcomes in the Western world. Epidemiological and medical contact recording do not exist outside central hospital...... level in Greenland, therefore, in order to put psychiatric contact patterns into perspective, in depth field studies are required in close collaboration with the local Greenlandic population...

  18. Determining Contact Angle and Surface Energy of Co60Fe20B20 Thin Films by Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    S. K. Wang

    2011-01-01

    Full Text Available This study examined the deposition of CoFeB thin films on a glass substrate at room temperature (RT, as well as the effects of conducting postannealing at heat annealing TA=150°C for 1 h. The thickness (tf of the CoFeB thin films ranged from 100 Å to 500 Å. The microstructure, average contact angle, and surface energy properties were also investigated. X-ray diffraction (XRD revealed that CoFeB films are nanocrystalline at RT and that post-annealing treatment increases in conjunction with the crystallinity. The surface energy of the CoFeB thin films is related to adhesive strength. The CoFeB films form a contact angle of larger than 90∘ with water as a test liquid. This finding demonstrates that the CoFeB film is hydrophobic. As tf increases from 100 Å to 500 Å, the surface energy at RT decreases from 40 mJ/mm2 to 32 mJ/mm2. During post-annealing treatment, the surface energy increases from 32 mJ/mm2 to 35 mJ/mm2, as tf increases from 100 Å to 300 Å; then it decreases to 31 mJ/mm2, as tf increases from 300 Å to 500 Å. The surface energy of the as-deposited CoFeB thin films exceeds that during post-annealing treatment at thicknesses of 100 Å and 200 Å, suggesting that as-deposited CoFeB thin film increases the adhesion.

  19. Acceptable risk of contact allergy in the general population assessed by CE-DUR--a method to detect and categorize contact allergy epidemics based on patient data

    DEFF Research Database (Denmark)

    Thyssen, Jacob Pontoppidan; Menné, Torkil; Schnuch, Axel;

    2009-01-01

    Over the 20th century, several contact allergy epidemics arose in Western Europe. Today, industries use various assays to determine the sensitization potential of new ingredients and thereby prevent new contact allergy outbreaks. This study debates acceptable risk of sensitization in the general...

  20. Evidence of double layer/capacitive charging in carbon nanomaterial-based solid contact polymeric ion-selective electrodes.

    Science.gov (United States)

    Cuartero, Maria; Bishop, Josiah; Walker, Raymart; Acres, Robert G; Bakker, Eric; De Marco, Roland; Crespo, Gaston A

    2016-08-11

    This paper presents the first direct spectroscopic evidence for double layer or capacitive charging of carbon nanomaterial-based solid contacts in all-solid-state polymeric ion-selective electrodes (ISEs). Here, we used synchrotron radiation-X-ray photoelectron spectroscopy (SR-XPS) and SR valence band (VB) spectroscopy in the elucidation of the charging mechanism of the SCs.

  1. Evidence of double layer/capacitive charging in carbon nanomaterial-based solid contact polymeric ion-selective electrodes.

    Science.gov (United States)

    Cuartero, Maria; Bishop, Josiah; Walker, Raymart; Acres, Robert G; Bakker, Eric; De Marco, Roland; Crespo, Gaston A

    2016-08-11

    This paper presents the first direct spectroscopic evidence for double layer or capacitive charging of carbon nanomaterial-based solid contacts in all-solid-state polymeric ion-selective electrodes (ISEs). Here, we used synchrotron radiation-X-ray photoelectron spectroscopy (SR-XPS) and SR valence band (VB) spectroscopy in the elucidation of the charging mechanism of the SCs. PMID:27405722

  2. Contact angle hysteresis of liquid drops as means to measure adhesive energy of zein on solid substrates

    Indian Academy of Sciences (India)

    L Muthuselvi; Aruna Dhathathreyan

    2006-03-01

    Adhesion of zein to solid substrates has been studied using surface energy profiles as indices and by adhesion mapping using atomic force microscopy (AFM). Different plasticizers like glycerol and sorbitol have been used to form mixed films with zein and properties of these films are studied using surface energy profiles. Comparison of the results from the different mixed samples with those from the pure zein films showed that force mapping could identify areas rich in protein. The adhesion maps produced were deconvoluted from sample topography and contrasted with the data obtained from contact angle measurements. A comparison of the two methods shows that the extent of contact angle hysteresis is indicative of both hydrophobicity of the surface as well as the force of adhesion. Mechanical properties and microstructure of zein films prepared by casting from solutions and using Langmuir-Blodgett film technique have been investigated. Pure zein seemed brittle and exhibited an essentially linear relationship between stress and strain. Films with plasticizer were tougher than these films. In general, mixed films showed better mechanical properties than pure films and had higher ultimate tensile strength and increased per cent elongation. Further, the mixed films of zein showed a higher force of adhesion compared to the pure films.

  3. Silicon quantum dots in SiO{sub x} dielectrics as energy selective contacts in hot carrier solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kar, Debjit; Das, Debajyoti, E-mail: erdd@iacs.res.in [Nano-Science Group, Energy Research Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata – 700032 (India)

    2015-06-24

    Thin films of c-Si QDs embedded in a-SiO{sub x} dielectric matrix was achieved at a low temperature ∼400°C, from one step process by reactive rf magnetron co-sputtering of c-Si wafer and pure SiO{sub 2} targets, in the (H{sub 2}+Ar)- plasma. Formation of a double-barrier structure has been primarily identified from the SAX data and exclusively confirmed from the resonant tunneling current appearing in the J-E characteristic curve peaks, determined by the discrete energy levels of c-Si QDs, at which it could be used as energy selective contacts in hot carrier solar cells.

  4. Micromotor-based energy generation.

    Science.gov (United States)

    Singh, Virendra V; Soto, Fernando; Kaufmann, Kevin; Wang, Joseph

    2015-06-01

    A micromotor-based strategy for energy generation, utilizing the conversion of liquid-phase hydrogen to usable hydrogen gas (H2), is described. The new motion-based H2-generation concept relies on the movement of Pt-black/Ti Janus microparticle motors in a solution of sodium borohydride (NaBH4) fuel. This is the first report of using NaBH4 for powering micromotors. The autonomous motion of these catalytic micromotors, as well as their bubble generation, leads to enhanced mixing and transport of NaBH4 towards the Pt-black catalytic surface (compared to static microparticles or films), and hence to a substantially faster rate of H2 production. The practical utility of these micromotors is illustrated by powering a hydrogen-oxygen fuel cell car by an on-board motion-based hydrogen and oxygen generation. The new micromotor approach paves the way for the development of efficient on-site energy generation for powering external devices or meeting growing demands on the energy grid.

  5. A Solid-Contact Indium(III) Sensor based on a Thiosulfinate Ionophore Derived from Omeprazole

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Mohammad Nooredeen; Hend Samy Amer [National Research Centre, Cairo (Egypt)

    2013-04-15

    A novel solid-contact indium(III)-selective sensor based on bis-(1H-benzimidazole-5-methoxy-2-[(4-methoxy-3, 5-dimethyl-1-pyridinyl) 2-methyl]) thiosulfinate, known as an omeprazole dimer (OD) and a neutral ionophore, was constructed, and its performance characteristics were evaluated. The sensor was prepared by applying a membrane cocktail containing the ionophore to a graphite rod pre-coated with polyethylene dioxythiophene (PEDOT) conducting polymer as the ion-to-electron transducer. The membrane contained 3.6% OD, 2.3% oleic acid (OA) and 62% dioctyl phthalate (DOP) as the solvent mediator in PVC and produced a good potentiometric response to indium(III) ions with a Nernstian slope of 19.09 mV/decade. The constructed sensor possessed a linear concentration range from 3 Χ 10{sup -7} to 1 Χ 10{sup -2} M and a lower detection limit (LDL) of 1 Χ 10{sup -7} M indium(III) over a pH range of 4.0-7.0. It also displayed a fast response time and good selectivity for indium(III) over several other ions. The sensor can be used for longer than three months without any considerable divergence in potential. The sensor was utilized for direct and flow injection potentiometric (FIP) determination of indium(III) in alloys. The parameters that control the flow injection method were optimized. Indium(III) was quantitatively recovered, and the results agreed with those obtained using atomic absorption spectrophotometry, as confirmed by the f and t values. The sensor was also utilized as an indicator electrode for the potentiometric titration of fluoride in the presence of chloride, bromide, iodide and thiocyanate ions using indium(III) nitrate as the titrant.

  6. "Click" Chemistry-Tethered Hyaluronic Acid-Based Contact Lens Coatings Improve Lens Wettability and Lower Protein Adsorption.

    Science.gov (United States)

    Deng, Xudong; Korogiannaki, Myrto; Rastegari, Banafsheh; Zhang, Jianfeng; Chen, Mengsu; Fu, Qiang; Sheardown, Heather; Filipe, Carlos D M; Hoare, Todd

    2016-08-31

    Improving the wettability of and reducing the protein adsorption to contact lenses may be beneficial for improving wearer comfort. Herein, we describe a simple "click" chemistry approach to surface functionalize poly(2-hydroxyethyl methacrylate) (pHEMA)-based contact lenses with hyaluronic acid (HA), a carbohydrate naturally contributing to the wettability of the native tear film. A two-step preparation technique consisting of laccase/TEMPO-mediated oxidation followed by covalent grafting of hydrazide-functionalized HA via simple immersion resulted in a model lens surface that is significantly more wettable, more water retentive, and less protein binding than unmodified pHEMA while maintaining the favorable transparency, refractive, and mechanical properties of a native lens. The dipping/coating method we developed to covalently tether the HA wetting agent is simple, readily scalable, and a highly efficient route for contact lens modification. PMID:27509015

  7. Terahertz magneto-spectroscopy of a point contact based on CdTe/CdMgTe quantum well

    Science.gov (United States)

    Grigelionis, Ignas; Białek, Marcin; Grynberg, Marian; Czapkiewicz, Magdalena; Kolkovskiy, Valery; Wiater, Maciej; Wojciechowski, Tomasz; Wróbel, Jerzy; Wojtowicz, Tomasz; Diakonova, Nina; Knap, Wojciech; Łusakowski, Jerzy

    2015-01-01

    To understand a terahertz (THz) response of a point contact device, a number of samples based on CdTe/CdMgTe quantum wells grown by a molecular beam epitaxy were investigated at low temperatures and high magnetic fields. The experiments involved magneto-transport, photocurrent, and transmission measurements carried out with monochromatic THz sources or a Fourier spectrometer. Samples of different geometry with and without gate metallization were used. We observed excitations of a two-dimensional electron plasma in the form of optically induced Shubnikov-de Haas oscillations, cyclotron resonance transitions, and magneto-plasmon resonances. A polaron effect was observed at magnetic fields higher than 10 T. A point contact device processed with an electron beam lithography was investigated as a detector of THz radiation. It was shown that the main mechanism responsible for a THz performance of the point contact was excitation of magneto-plasmons with a wavevector defined by geometrical constrictions of the device mesa.

  8. Explicit-Explicit Sequence Calculation Method for the Wheel/rail Rolling Contact Problem Based on ANSYS/LS-DYNA

    Directory of Open Access Journals (Sweden)

    Song Hua

    2015-01-01

    Full Text Available The wheel/rail rolling contact can not only lead to rail fatigue damage but also bring rail corrugation. According to the wheel/rail rolling contact problem, based on the ANSYS/LS-DYNA explicit analysis software, this paper established the finite element model of wheel/rail rolling contact in non-linear steady-state curve negotiation, and proposed the explicit-explicit sequence calculation method that can be used to solve this model. The explicit-explicit sequence calculation method uses explicit solver in calculating the rail pre-stressing force and the process of wheel/rail rolling contact. Compared with the implicit-explicit sequence calculation method that has been widely applied, the explicit-explicit sequence calculation method including similar precision in calculation with faster speed and higher efficiency, make it more applicable to solve the wheel/rail rolling contact problem of non-linear steady-state curving with a large solving model or a high non-linear degree.

  9. Analysis of Seismic Damage of Underground Powerhouse Structure of Hydropower Plants Based on Dynamic Contact Force Method

    Directory of Open Access Journals (Sweden)

    Yang Yang

    2014-01-01

    Full Text Available Based on the characteristics of the dynamic interaction between an underground powerhouse concrete structure and its surrounding rock in a hydropower plant, an algorithm of dynamic contact force was proposed. This algorithm enables the simulation of three states of contact surface under dynamic loads, namely, cohesive contact, sliding contact, and separation. It is suitable for the numerical analysis of the dynamic response of the large and complex contact system consisting of underground powerhouse concrete structure and the surrounding rock. This algorithm and a 3D plastic-damage model were implemented in a dynamic computing platform, SUCED, to analyze the dynamic characteristics of the underground powerhouse structure of Yingxiuwan Hydropower Plant. By comparing the numerical results and postearthquake investigations, it was concluded that the amplitude and duration of seismic waves were the external factors causing seismic damage of the underground powerhouse structure, and the spatial variations in structural properties were the internal factors. The existence of rock mass surrounding the underground powerhouse was vital to the seismic stability of the structure. This work provides the theoretical basis for the anti-seismic design of underground powerhouse structures.

  10. Accuracy of model-based tracking of knee kinematics and cartilage contact measured by dynamic volumetric MRI.

    Science.gov (United States)

    Kaiser, Jarred; Monawer, Arezu; Chaudhary, Rajeev; Johnson, Kevin M; Wieben, Oliver; Kijowski, Richard; Thelen, Darryl G

    2016-10-01

    The purpose of this study was to determine the accuracy of knee kinematics and cartilage contact measured by volumetric dynamic MRI. A motor-actuated phantom drove femoral and tibial bone segments through cyclic 3D motion patterns. Volumetric images were continuously acquired using a 3D radially undersampled cine spoiled gradient echo sequence (SPGR-VIPR). Image data was binned based on position measured via a MRI-compatible rotary encoder. High-resolution static images were segmented to create bone models. Model-based tracking was performed by optimally registering the bone models to the volumetric images at each frame of the SPGR-VIPR series. 3D tibiofemoral translations and orientations were reconstructed, and compared to kinematics obtained by tracking fiducial markers. Imaging was repeated on a healthy subject who performed cyclic knee flexion-extension. Cartilage contact for the subject was assessed by measuring the overlap between articular cartilage surfaces. Model-based tracking was able to track tibiofemoral angles and translations with precisions less than 0.8° and 0.5mm. These precisions resulted in an uncertainty of less than 0.5mm in cartilage contact location. Dynamic SPGR-VIPR imaging can accurately assess in vivo knee kinematics and cartilage contact during voluntary knee motion performed in a MRI scanner. This technology could facilitate the quantitative investigation of links between joint mechanics and the development of osteoarthritis. PMID:27387902

  11. Accuracy of model-based tracking of knee kinematics and cartilage contact measured by dynamic volumetric MRI.

    Science.gov (United States)

    Kaiser, Jarred; Monawer, Arezu; Chaudhary, Rajeev; Johnson, Kevin M; Wieben, Oliver; Kijowski, Richard; Thelen, Darryl G

    2016-10-01

    The purpose of this study was to determine the accuracy of knee kinematics and cartilage contact measured by volumetric dynamic MRI. A motor-actuated phantom drove femoral and tibial bone segments through cyclic 3D motion patterns. Volumetric images were continuously acquired using a 3D radially undersampled cine spoiled gradient echo sequence (SPGR-VIPR). Image data was binned based on position measured via a MRI-compatible rotary encoder. High-resolution static images were segmented to create bone models. Model-based tracking was performed by optimally registering the bone models to the volumetric images at each frame of the SPGR-VIPR series. 3D tibiofemoral translations and orientations were reconstructed, and compared to kinematics obtained by tracking fiducial markers. Imaging was repeated on a healthy subject who performed cyclic knee flexion-extension. Cartilage contact for the subject was assessed by measuring the overlap between articular cartilage surfaces. Model-based tracking was able to track tibiofemoral angles and translations with precisions less than 0.8° and 0.5mm. These precisions resulted in an uncertainty of less than 0.5mm in cartilage contact location. Dynamic SPGR-VIPR imaging can accurately assess in vivo knee kinematics and cartilage contact during voluntary knee motion performed in a MRI scanner. This technology could facilitate the quantitative investigation of links between joint mechanics and the development of osteoarthritis.

  12. COMSAT: Residue contact prediction of transmembrane proteins based on support vector machines and mixed integer linear programming.

    Science.gov (United States)

    Zhang, Huiling; Huang, Qingsheng; Bei, Zhendong; Wei, Yanjie; Floudas, Christodoulos A

    2016-03-01

    In this article, we present COMSAT, a hybrid framework for residue contact prediction of transmembrane (TM) proteins, integrating a support vector machine (SVM) method and a mixed integer linear programming (MILP) method. COMSAT consists of two modules: COMSAT_SVM which is trained mainly on position-specific scoring matrix features, and COMSAT_MILP which is an ab initio method based on optimization models. Contacts predicted by the SVM model are ranked by SVM confidence scores, and a threshold is trained to improve the reliability of the predicted contacts. For TM proteins with no contacts above the threshold, COMSAT_MILP is used. The proposed hybrid contact prediction scheme was tested on two independent TM protein sets based on the contact definition of 14 Å between Cα-Cα atoms. First, using a rigorous leave-one-protein-out cross validation on the training set of 90 TM proteins, an accuracy of 66.8%, a coverage of 12.3%, a specificity of 99.3% and a Matthews' correlation coefficient (MCC) of 0.184 were obtained for residue pairs that are at least six amino acids apart. Second, when tested on a test set of 87 TM proteins, the proposed method showed a prediction accuracy of 64.5%, a coverage of 5.3%, a specificity of 99.4% and a MCC of 0.106. COMSAT shows satisfactory results when compared with 12 other state-of-the-art predictors, and is more robust in terms of prediction accuracy as the length and complexity of TM protein increase. COMSAT is freely accessible at http://hpcc.siat.ac.cn/COMSAT/.

  13. a-Si:H/c-Si heterojunction front- and back contacts for silicon solar cells with p-type base

    Energy Technology Data Exchange (ETDEWEB)

    Rostan, Philipp Johannes

    2010-07-01

    This thesis reports on low temperature amorphous silicon back and front contacts for high-efficiency crystalline silicon solar cells with a p-type base. The back contact uses a sequence of intrinsic amorphous (i-a-Si:H) and boron doped microcrystalline (p-{mu}c-Si:H) silicon layers fabricated by Plasma Enhanced Chemical Vapor Deposition (PECVD) and a magnetron sputtered ZnO:Al layer. The back contact is finished by evaporating Al onto the ZnO:Al and altogether prepared at a maximum temperature of 220 C. Analysis of the electronic transport of mobile charge carriers at the back contact shows that the two high-efficiency requirements low back contact series resistance and high quality c-Si surface passivation are in strong contradiction to each other, thus difficult to achieve at the same time. The preparation of resistance- and effective lifetime samples allows one to investigate both requirements independently. Analysis of the majority charge carrier transport on complete Al/ZnO:Al/a-Si:H/c-Si back contact structures derives the resistive properties. Measurements of the effective minority carrier lifetime on a-Si:H coated wafers determines the back contact surface passivation quality. Both high-efficiency solar cell requirements together are analyzed in complete photovoltaic devices where the back contact series resistance mainly affects the fill factor and the back contact passivation quality mainly affects the open circuit voltage. The best cell equipped with a diffused emitter with random texture and a full-area a-Si:H/c-Si back contact has an independently confirmed efficiency {eta} = 21.0 % with an open circuit voltage V{sub oc} = 681 mV and a fill factor FF = 78.7 % on an area of 1 cm{sup 2}. An alternative concept that uses a simplified a-Si:H layer sequence combined with Al-point contacts yields a confirmed efficiency {eta} = 19.3 % with an open circuit voltage V{sub oc} = 655 mV and a fill factor FF = 79.5 % on an area of 2 cm{sup 2}. Analysis of the

  14. Toxicity testing and chemical analyses of recycled fibre-based paper for food contact

    DEFF Research Database (Denmark)

    Binderup, Mona-Lise; Pedersen, Gitte Alsing; Vinggaard, Anne;

    2002-01-01

    Food-contact materials, including paper, have to comply with a basic set of criteria concerning safety. This means that paper for food contact should not give rise to migration of components, which can endanger human health. The objectives of this pilot study were, first, to compare paper...... of different qualities as food-contact materials and to Perform a preliminary evaluation of their suitability from a safety point of view, and, second, to evaluate the use of different in vitro toxicity tests for screening of paper and board. Paper produced from three different categories of recycled fibres (B...... for mutagenic and potentially carcinogenic compounds; (3) a recombinant yeast cell bioassay as a screening test for compounds with oestrogenic activity; (4) an aryl hydrocarbon (Ah)-receptor assay (CALUX assay) as a screening test for compounds with dioxin-like activity. In addition, the papers were tested...

  15. Toward energy-neutral wastewater treatment: a high-rate contact stabilization process to maximally recover sewage organics.

    Science.gov (United States)

    Meerburg, Francis A; Boon, Nico; Van Winckel, Tim; Vercamer, Jensen A R; Nopens, Ingmar; Vlaeminck, Siegfried E

    2015-03-01

    The conventional activated sludge process is widely used for wastewater treatment, but to progress toward energy self-sufficiency, the wastewater treatment scheme needs to radically improve energy balances. We developed a high-rate contact stabilization (HiCS) reactor system at high sludge-specific loading rates (>2 kg bCOD kg(-1)TSS d(-1)) and low sludge retention times (organics than high-rate conventional activated sludge (HiCAS) and the low-rate variants of HiCS and HiCAS. The best HiCS system recovered 36% of the influent chemical energy as methane, due to the combined effects of low production of CO2, high sludge yield, and high methane yield of the produced sludge. The HiCS system imposed a feast-famine cycle and a putative selection pressure on the sludge micro-organisms toward substrate adsorption and storage. Given further optimization, it is a promising process for energy recovery from wastewater.

  16. AFM-based tribological study of nanopatterned surfaces: the influence of contact area instabilities

    International Nuclear Information System (INIS)

    Although the importance of morphology on the tribological properties of surfaces has long been proved, an exhaustive understanding of nanopatterning effects is still lacking due to the difficulty in both fabricating ‘really nano-’ structures and detecting their tribological properties. In the present work we show how the probe–surface contact area can be a critical parameter due to its remarkable local variability, making a correct interpretation of the data very difficult in the case of extremely small nanofeatures. Regular arrays of parallel 1D straight nanoprotrusions were fabricated by means of a low-dose focused ion beam, taking advantage of the amorphization-related swelling effect. The tribological properties of the patterns were detected in the presence of air and in vacuum (dry ambient) by atomic force microscopy. We have introduced a novel procedure and data analysis to reduce the uncertainties related to contact instabilities. The real time estimation of the radius of curvature of the contacting asperity enables us to study the dependence of the tribological properties of the patterns from their geometrical characteristics. The effect of the patterns on both adhesion and the coefficient of friction strongly depends on the contact area, which is linked to the local radius of curvature of the probe. However, a detectable hydrophobic character induced on the hydrophilic native SiO2 has been observed as well. The results suggest a scenario for capillary formation on the patterns. (paper)

  17. Normal and Friction Stabilization Techniques for Interactive Rigid Body Constraint-based Contact Force Computations

    DEFF Research Database (Denmark)

    Silcowitz, Morten; Niebe, Sarah Maria; Erleben, Kenny

    2010-01-01

    We present a novel, yet simple, method for stabilization of normal forces. A normal stabilization term, carefully designed from hypotheses about interactive usability, is added to the contact force problem. Further, we propose friction stabilization as a completely new stabilization paradigm in i...

  18. Zip:An Algorithm Based on Loser Tree for Common Contacts Searching in Large Graphs

    Institute of Scientific and Technical Information of China (English)

    唐宏; 牟帅; 黄晋; 朱佳; 陈健; 丁蕊

    2015-01-01

    The problem of k-hop reachability between two vertices in a graph has received considerable attention in recent years. A substantial number of algorithms have been proposed with the goal of improving the searching efficiency of the k-hop reachability between two vertices in a graph. However, searching and traversing are challenging tasks, especially in large-scale graphs. Furthermore, the existing algorithms propounded by different scholars are not satisfactory in terms of feasibility and scalability when applied to different kinds of graphs. In this work, we propose a new algorithm, called Zip, in an attempt to efficiently determine the common contacts between any two random vertices in a large-scale graph. First, we describe a novel algorithm for constructing the graph index via binary searching which maintains the adjacent list of each vertex in order. Second, we present the ways to achieve a sequential k-hop contact set by using the loser tree, a merge sorting algorithm. Finally, we develop an efficient algorithm for querying common contacts and an optimized strategy for k-hop contact set serialization. Experimental results on synthetic and real datasets show that the proposed Zip algorithm outperforms existing state-of-the-art algorithms (e.g., breadth-first searching, GRAIL, the graph stratification algorithm).

  19. Contact dermatitis to hair dyes in a Danish adult population: an interview-based study

    DEFF Research Database (Denmark)

    Søsted, H; Hesse, U; Menné, T;

    2005-01-01

    .3% of individuals who had ever used hair dye. Of these, only 15.6% had been in contact with healthcare services after the hair dye reaction. Having had a temporary tattoo was not a significant risk factor for an adverse reaction to hair dyes. CONCLUSIONS: The rate of adverse allergic skin reactions to hair dyes...

  20. The Degradation Interface of Magnesium Based Alloys in Direct Contact with Human Primary Osteoblast Cells.

    Directory of Open Access Journals (Sweden)

    Nezha Ahmad Agha

    Full Text Available Magnesium alloys have been identified as a new generation material of orthopaedic implants. In vitro setups mimicking physiological conditions are promising for material / degradation analysis prior to in vivo studies however the direct influence of cell on the degradation mechanism has never been investigated. For the first time, the direct, active, influence of human primary osteoblasts on magnesium-based materials (pure magnesium, Mg-2Ag and Mg-10Gd alloys is studied for up to 14 days. Several parameters such as composition of the degradation interface (directly beneath the cells are analysed with a scanning electron microscope equipped with energy dispersive X-ray and focused ion beam. Furthermore, influence of the materials on cell metabolism is examined via different parameters like active mineralisation process. The results are highlighting the influences of the selected alloying element on the initial cells metabolic activity.

  1. Energy conservation employing membrane-based technology

    International Nuclear Information System (INIS)

    Membranes based processes, if properly adapted to industrial processes have good potential with regard to optimisation and economisation of energy consumption. The specific benefits of MBT (membrane based technology) as an energy conservation methodology are highlighted. (author). 6 refs

  2. 75 FR 14342 - Market-Based Rates for Wholesale Sales of Electric Energy, Capacity and Ancillary Services by...

    Science.gov (United States)

    2010-03-25

    ... Energy Regulatory Commission 18 CFR Part 35 Market-Based Rates for Wholesale Sales of Electric Energy... INFORMATION CONTACT: Michelle Barnaby (Technical Information), Office of Energy Market Regulation, Federal.... ] 31,291 (2009). \\2\\ 18 CFR 35.42. \\3\\ Market-Based Rates for Wholesale Sales of Electric...

  3. Beyond Contact Tracing: Community-Based Early Detection for Ebola Response

    CERN Document Server

    Cooney, Daniel; Bar-Yam, Yaneer

    2015-01-01

    The 2014 Ebola outbreak in west Africa raised many questions about the control of infectious disease in an increasingly connected global society. Limited availability of contact information has made contact tracing difficult or impractical in combating the outbreak. We consider the development of multi-scale public health strategies and simulate policies for community-level response aimed at early screening of communities rather than individuals, as well as travel restrictions to prevent community cross-contamination. Our analysis shows community screening to be effective even at a relatively low level of compliance. In our simulations, 40% of individuals conforming to this policy is enough to stop the outbreak. Simulations with a 50% compliance rate are consistent with the case counts in Liberia during the period of rapid decline after mid September, 2014. We also find the travel restriction policies to be effective at reducing the risks associated with compliance substantially below the 40% level, shortenin...

  4. Low-temperature sintering of lanthanum strontium manganite-based contact pastes for SOFCs

    Science.gov (United States)

    McCarthy, B. P.; Pederson, L. R.; Chou, Y. S.; Zhou, X.-D.; Surdoval, W. A.; Wilson, L. C.

    Electrical contact pastes of composition (La 0.90Sr 0.10) 0.98MnO 3 + δ (LSM-10) formed strong bonds (∼3 MPa) to (Co,Mn) 3O 4 spinel-coated Crofer 22 APU ferritic steel coupons when exposed to alternating flows of air and nitrogen (10 ppm O 2) at 900 °C for 2 h or longer. When held at 900 °C in air only, bond strengths were negligible. Substantial bonds could also be created between LSM-10 contact paste and (La 0.80Sr 0.20) 0.98MnO 3 + δ (LSM-20) porous cathodes by processing in alternating air and nitrogen, without simultaneous densification of the cathode. Enhanced sintering of LSM-10 is attributed to transients in the defect structure induced by oxygen partial pressure changes.

  5. Investigation on Thermal Contact Conductance Based on Data Analysis Method of Reliability

    Institute of Scientific and Technical Information of China (English)

    WANG Zongren; YANG Jun; YANG Mingyuan; ZHANG Weifang

    2012-01-01

    The method of reliability is proposed for the investigation of thermal contact conductance (TCC) in this study.A new definition is introduced,namely reliability thermal contact conductance (RTCC),which is defined as the TCC value that meets the reliability design requirement of the structural materials under consideration.An experimental apparatus with the compensation heater to test the TCC is introduced here.A practical engineering example is utilized to demonstrate the applicability of the proposed approach.By using a statistical regression model along with experimental data obtained from the interfaces of the structural materials GH4169 and K417 used in aero-engine,the estimate values and the confidence level of TCC and RTCC values are studied and compared.The results show that the testing values of TCC increase with interface pressure and the proposed RTCC model matches the test results better at high interface pressure.

  6. An energy-saving opportunity in producing lubricating oil using mixed-solventin simulated Rotary Disc Contacting (RDC) extraction tower

    Energy Technology Data Exchange (ETDEWEB)

    Hatamipour, M.S.; Fakhr Hoseini, S.M.; Tavakkoli, T.; Mehrkesh, A.H. [Chemical Engineering Department, University of Isfahan, Isfahan (Iran)

    2010-05-15

    Industrial processes are the most energy consuming processes in the world. Modification of these processes helps us with controlling the consumption of energy and minimizing energy loss. Changing raw materials is one of the ways through which we can optimize industrial processes. In this paper, a new solvent mixture (furfural + a co-solvent) was used for the extraction of lubricating base oil from lube-oil cut. It was found that the energy consumption of the new solvent mixture for obtaining a product with the same quality was much lower than the original solvent. By using this new solvent mixture, the operating temperature of the top of tower was reduced by 30 K. This leads to a high reduction in energy consumption in extraction of aromatics from lube oil. At our new extraction process by means of using new solvent mixture, the maximum energy saving was 38% per cubic meter of produced raffinate. (author)

  7. EPOXY COMPOSITE BASED ON KENAF FIBERS FOR TRIBOLOGICAL APPLICATIONS UNDER WET CONTACT CONDITIONS

    OpenAIRE

    B. F. YOUSIF; C. W. Chin

    2012-01-01

    In the current work, kenaf fibers reinforced epoxy (KFRE) composite was developed. Adhesive wear and frictional characteristics of KFRE were investigated under wet contact conditions at different fiber orientations, considering different applied loads (50–200 N) and sliding distances (0–30 km). Scanning electron microscopy (SEM) was used to observe the damages on the worn surfaces. The results revealed that fiber orientation plays a main role in determining the wear and frictional performance...

  8. Beyond Contact Tracing: Community-Based Early Detection for Ebola Response

    Science.gov (United States)

    Wong, Vincent; Cooney, Daniel; Bar-Yam, Yaneer

    2016-01-01

    Introduction: The 2014 Ebola outbreak in West Africa raised many questions about the control of infectious disease in an increasingly connected global society. Limited availability of contact information made contact tracing diffcult or impractical in combating the outbreak.  Methods: We consider the development of multi-scale public health strategies that act on individual and community levels. We simulate policies for community-level response aimed at early screening all members of a community, as well as travel restrictions to prevent inter-community transmission.  Results: Our analysis shows the policies to be effective even at a relatively low level of compliance and for a variety of local and long range contact transmission networks. In our simulations, 40% of individuals conforming to these policies is enough to stop the outbreak. Simulations with a 50% compliance rate are consistent with the case counts in Liberia during the period of rapid decline after mid September, 2014. We also find the travel restriction to be effective at reducing the risks associated with compliance substantially below the 40% level, shortening the outbreak and enabling efforts to be focused on affected areas.  Discussion: Our results suggest that the multi-scale approach can be used to further evolve public health strategy for defeating emerging epidemics. PMID:27486552

  9. Time-lapse contact microscopy of cell cultures based on non-coherent illumination

    Science.gov (United States)

    Gabriel, Marion; Balle, Dorothée; Bigault, Stéphanie; Pornin, Cyrille; Gétin, Stéphane; Perraut, François; Block, Marc R.; Chatelain, François; Picollet-D'Hahan, Nathalie; Gidrol, Xavier; Haguet, Vincent

    2015-10-01

    Video microscopy offers outstanding capabilities to investigate the dynamics of biological and pathological mechanisms in optimal culture conditions. Contact imaging is one of the simplest imaging architectures to digitally record images of cells due to the absence of any objective between the sample and the image sensor. However, in the framework of in-line holography, other optical components, e.g., an optical filter or a pinhole, are placed underneath the light source in order to illuminate the cells with a coherent or quasi-coherent incident light. In this study, we demonstrate that contact imaging with an incident light of both limited temporal and spatial coherences can be achieved with sufficiently high quality for most applications in cell biology, including monitoring of cell sedimentation, rolling, adhesion, spreading, proliferation, motility, death and detachment. Patterns of cells were recorded at various distances between 0 and 1000 μm from the pixel array of the image sensors. Cells in suspension, just deposited or at mitosis focalise light into photonic nanojets which can be visualised by contact imaging. Light refraction by cells significantly varies during the adhesion process, the cell cycle and among the cell population in connection with every modification in the tridimensional morphology of a cell.

  10. Novel top-contact monolayer pentacene-based thin-film transistor for ammonia gas detection.

    Science.gov (United States)

    Mirza, Misbah; Wang, Jiawei; Li, Dexing; Arabi, S Atika; Jiang, Chao

    2014-04-23

    We report on the fabrication of an organic field-effect transistor (OFET) of a monolayer pentacene thin film with top-contact electrodes for the aim of ammonia (NH3) gas detection by monitoring changes in its drain current. A top-contact configuration, in which source and drain electrodes on a flexible stamp [poly(dimethylsiloxane)] were directly contacted with the monolayer pentacene film, was applied to maintain pentacene arrangement ordering and enhance the monolayer OFET detection performance. After exposure to NH3 gas, the carrier mobility at the monolayer OFET channel decreased down to one-third of its original value, leading to a several orders of magnitude decrease in the drain current, which tremendously enhanced the gas detection sensitivity. This sensitivity enhancement to a limit of the 10 ppm level was attributed to an increase of charge trapping in the carrier channel, and the amount of trapped states was experimentally evaluated by the threshold voltage shift induced by the absorbed NH3 molecular analyte. In contrast, a conventional device with a 50-nm-thick pentacene layer displayed much higher mobility but lower response to NH3 gas, arising from the impediment of analyte penetrating into the conductive channel, owing to the thick pentacene film.

  11. Time-lapse contact microscopy of cell cultures based on non-coherent illumination.

    Science.gov (United States)

    Gabriel, Marion; Balle, Dorothée; Bigault, Stéphanie; Pornin, Cyrille; Gétin, Stéphane; Perraut, François; Block, Marc R; Chatelain, François; Picollet-D'hahan, Nathalie; Gidrol, Xavier; Haguet, Vincent

    2015-01-01

    Video microscopy offers outstanding capabilities to investigate the dynamics of biological and pathological mechanisms in optimal culture conditions. Contact imaging is one of the simplest imaging architectures to digitally record images of cells due to the absence of any objective between the sample and the image sensor. However, in the framework of in-line holography, other optical components, e.g., an optical filter or a pinhole, are placed underneath the light source in order to illuminate the cells with a coherent or quasi-coherent incident light. In this study, we demonstrate that contact imaging with an incident light of both limited temporal and spatial coherences can be achieved with sufficiently high quality for most applications in cell biology, including monitoring of cell sedimentation, rolling, adhesion, spreading, proliferation, motility, death and detachment. Patterns of cells were recorded at various distances between 0 and 1000 μm from the pixel array of the image sensors. Cells in suspension, just deposited or at mitosis focalise light into photonic nanojets which can be visualised by contact imaging. Light refraction by cells significantly varies during the adhesion process, the cell cycle and among the cell population in connection with every modification in the tridimensional morphology of a cell. PMID:26459014

  12. a-Si:H/c-Si heterojunction front- and back contacts for silicon solar cells with p-type base

    Energy Technology Data Exchange (ETDEWEB)

    Rostan, Philipp Johannes

    2010-07-01

    This thesis reports on low temperature amorphous silicon back and front contacts for high-efficiency crystalline silicon solar cells with a p-type base. The back contact uses a sequence of intrinsic amorphous (i-a-Si:H) and boron doped microcrystalline (p-{mu}c-Si:H) silicon layers fabricated by Plasma Enhanced Chemical Vapor Deposition (PECVD) and a magnetron sputtered ZnO:Al layer. The back contact is finished by evaporating Al onto the ZnO:Al and altogether prepared at a maximum temperature of 220 C. Analysis of the electronic transport of mobile charge carriers at the back contact shows that the two high-efficiency requirements low back contact series resistance and high quality c-Si surface passivation are in strong contradiction to each other, thus difficult to achieve at the same time. The preparation of resistance- and effective lifetime samples allows one to investigate both requirements independently. Analysis of the majority charge carrier transport on complete Al/ZnO:Al/a-Si:H/c-Si back contact structures derives the resistive properties. Measurements of the effective minority carrier lifetime on a-Si:H coated wafers determines the back contact surface passivation quality. Both high-efficiency solar cell requirements together are analyzed in complete photovoltaic devices where the back contact series resistance mainly affects the fill factor and the back contact passivation quality mainly affects the open circuit voltage. The best cell equipped with a diffused emitter with random texture and a full-area a-Si:H/c-Si back contact has an independently confirmed efficiency {eta} = 21.0 % with an open circuit voltage V{sub oc} = 681 mV and a fill factor FF = 78.7 % on an area of 1 cm{sup 2}. An alternative concept that uses a simplified a-Si:H layer sequence combined with Al-point contacts yields a confirmed efficiency {eta} = 19.3 % with an open circuit voltage V{sub oc} = 655 mV and a fill factor FF = 79.5 % on an area of 2 cm{sup 2}. Analysis of the

  13. CFD simulation of direct contact condensation with ANSYS CFX using surface renewal theory based heat transfer coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Wanninger, Andreas; Ceuca, Sabin Cristian; Macian-Juan, Rafael [Technische Univ. Muenchen, Garching (Germany). Dept. of Nuclear Engineering

    2013-07-01

    Different approaches for the calculation of Direct Contact Condensation (DCC) using Heat Transfer Coefficients (HTC) based on the Surface Renewal Theory (SRT) are tested using the CFD simulation tool ANSYS CFX. The present work constitutes a preliminary study of the flow patterns and conditions observed using different HTC models. A complex 3D flow pattern will be observed in the CFD simulations as well as a strong coupling between the condensation rate and the two-phase flow dynamics. (orig.)

  14. Energy based hybrid turbulence modeling

    Science.gov (United States)

    Haering, Sigfried; Moser, Robert

    2015-11-01

    Traditional hybrid approaches exhibit deficiencies when used for fluctuating smooth-wall separation and reattachment necessitating ad-hoc delaying functions and model tuning making them no longer useful as a predictive tool. Additionally, complex geometries and flows often require high cell aspect-ratios and large grid gradients as a compromise between resolution and cost. Such transitions and inconsistencies in resolution detrimentally effect the fidelity of the simulation. We present the continued development of a new hybrid RANS/LES modeling approach specifically developed to address these challenges. In general, modeled turbulence is returned to resolved scales by reduced or negative model viscosity until a balance between theoretical and actual modeled turbulent kinetic energy is attained provided the available resolution. Anisotropy in the grid and resolved field are directly integrated into this balance. A viscosity-based correction is proposed to account for resolution inhomogeneities. Both the hybrid framework and resolution gradient corrections are energy conserving through an exchange of resolved and modeled turbulence.

  15. Metal-clad waveguide characterization for contact-based light transmission into tissue

    Science.gov (United States)

    Chininis, Jeffrey; Whiteside, Paul; Hunt, Heather K.

    2016-02-01

    As contemporary laser dermatology procedures, like tattoo removal and skin resurfacing, become more popular, the complications of their operation are also becoming more prevalent. Frequent incidences of over-exposure, ocular injury, and excessive thermal damage represent mounting concerns for those seeking such procedures; moreover, each of these problems is a direct consequence of the standard, free-space method of laser transmission predominantly used in clinical settings. Therefore, an alternative method of light transmission is needed to minimize these problems. Here, we demonstrate and characterize an alternative method that uses planar waveguides to deliver light into sample tissue via direct contact. To do this, slab substrates made from glass were clad in layers of titanium and silver, constraining the light within the waveguide along the waveguide's length. By creating active areas on the waveguide surface, the propagating light could then optically tunnel into the tissue sample, when the waveguide was brought into contact with the tissue. SEM and EDS were used to characterize the metal film thickness and deposition rates onto the glass substrates. Laser light from a Q-switched Nd:YAG source operating at 532nm was coupled into the waveguide and transmitted into samples of pig skin. The amount of light transmitted was measured using photoacoustics techniques, in conjunction with a photodiode and integrating sphere. Transmitting light into tissue in this manner effectively resolves or circumvents the complications caused by free-space propagation methods as it reduces the operating distance to 0, which prevents hazardous back-reflections and allows for the ready incorporation of contact cooling technologies.

  16. Ranking multiple docking solutions based on the conservation of inter-residue contacts

    KAUST Repository

    Oliva, Romina M.

    2013-06-17

    Molecular docking is the method of choice for investigating the molecular basis of recognition in a large number of functional protein complexes. However, correctly scoring the obtained docking solutions (decoys) to rank native-like (NL) conformations in the top positions is still an open problem. Herein we present CONSRANK, a simple and effective tool to rank multiple docking solutions, which relies on the conservation of inter-residue contacts in the analyzed decoys ensemble. First it calculates a conservation rate for each inter-residue contact, then it ranks decoys according to their ability to match the more frequently observed contacts. We applied CONSRANK to 102 targets from three different benchmarks, RosettaDock, DOCKGROUND, and Critical Assessment of PRedicted Interactions (CAPRI). The method performs consistently well, both in terms of NL solutions ranked in the top positions and of values of the area under the receiver operating characteristic curve. Its ideal application is to solutions coming from different docking programs and procedures, as in the case of CAPRI targets. For all the analyzed CAPRI targets where a comparison is feasible, CONSRANK outperforms the CAPRI scorers. The fraction of NL solutions in the top ten positions in the RosettaDock, DOCKGROUND, and CAPRI benchmarks is enriched on average by a factor of 3.0, 1.9, and 9.9, respectively. Interestingly, CONSRANK is also able to specifically single out the high/medium quality (HMQ) solutions from the docking decoys ensemble: it ranks 46.2 and 70.8% of the total HMQ solutions available for the RosettaDock and CAPRI targets, respectively, within the top 20 positions. © 2013 Wiley Periodicals, Inc.

  17. Chemical structure of vanadium-based contact formation on n-AlN

    International Nuclear Information System (INIS)

    We have investigated the chemical interaction between a Au/V/Al/V layer structure and n-type AlN epilayers using soft x-ray photoemission, x-ray emission spectroscopy, and atomic force microscopy. To understand the complex processes involved in this multicomponent system, we have studied the interface before and after a rapid thermal annealing step. We find the formation of a number of chemical phases at the interface, including VN, metallic vanadium, aluminum oxide, and metallic gold. An interaction mechanism for metal contact formation on the entire n-(Al,Ga)N system is proposed.

  18. Development of steel head joints with fiberglass sucker rod on the base of contact stresses investigation

    Energy Technology Data Exchange (ETDEWEB)

    Kopey, B.V.; Kopey, L.B. [Ivano-Frankivsk State Technical Oil and Gas University (Ukraine); Maksymuk, A.V.; Shcherbyna, N.M. [National Ukrainian Academy of Sciences (Ukraine)

    1998-12-31

    The methods of calculation of contact stresses during cylinder shell tube - steel bandage interaction are presented. Tymoshenko`s generalized theory of shells serves as a basis for investigating steel head to fiberglass sucker rod joint strength. This theory allows to consider mechanical performance of composite materials. The problem is reduced to solving Fredholm integral equation of second degree. The numeric analysis is performed. Several joints of composite body with steel head are proposed. The full-size sucker rod fatigue tests are performed to determine the fatigue limit under the bending and axial cyclic loads in the medium of oil well fluids. (orig.)

  19. Chemical structure of vanadium-based contact formation on n-AlN

    Energy Technology Data Exchange (ETDEWEB)

    Pookpanratana, S.; France, R.; Blum, M.; Bell, A.; Bar, M.; Weinhardt, L.; Zhang, Y.; Hofmann, T.; Fuchs, O.; Yang, W.; Denlinger, J. D.; Mulcahy, S.; Moustakas, T. D.; Heske, Clemens

    2010-05-17

    We have investigated the chemical interaction between a Au/V/Al/V layer structure and n-type AlN epilayers using soft x-ray photoemission, x-ray emission spectroscopy, and atomic force microscopy. To understand the complex processes involved in this multicomponent system, we have studied the interface before and after a rapid thermal annealing step. We find the formation of a number of chemical phases at the interface, including VN, metallic vanadium, aluminum oxide, and metallic gold. An interaction mechanism for metal contact formation on the entire n-(Al,Ga)N system is proposed.

  20. Wind energy harvesting and self-powered flow rate sensor enabled by contact electrification

    Science.gov (United States)

    Su, Yuanjie; Xie, Guangzhong; Xie, Tao; Zhang, Hulin; Ye, Zongbiao; Jing, Qingshen; Tai, Huiling; Du, Xiaosong; Jiang, Yadong

    2016-06-01

    We have developed a free-standing-mode based triboelectric nanogenerator (F-TENG) that consists of indium tin oxide (ITO) foils and a polytetrafluoroethylene (PTFE) thin film. By utilizing the wind-induced resonance vibration of a PTFE film between two ITO electrodes, the F-TENG delivers an open-circuit voltage up to 37 V and a short-circuit current of 6.2 μA, which can be used as a sustainable power source to simultaneously and continuously light up tens of light emitting diodes (LEDs) and charge capacitors. Moreover, uniform division of the electrode into several parallel units efficiently suppresses the inner counteracting effect of undulating film and leads to an enhancement of output current by 95%. The F-TENG holds prominent durability and an excellent linear relationship between output current and flow rate, revealing its feasibility as a self-powered sensor for detecting wind speed. This work demonstrates potential applications of the triboelectric generator in gas flow harvesters, self-powered air navigation, self-powered gas sensors and wind vector sensors.

  1. Beyond contact-based transmission networks: the role of spatial coincidence.

    Science.gov (United States)

    Richardson, Thomas O; Gorochowski, Thomas E

    2015-10-01

    Animal societies rely on interactions between group members to effectively communicate and coordinate their actions. To date, the transmission properties of interaction networks formed by direct physical contacts have been extensively studied for many animal societies and in all cases found to inhibit spreading. Such direct interactions do not, however, represent the only viable pathways. When spreading agents can persist in the environment, indirect transmission via 'same-place, different-time' spatial coincidences becomes possible. Previous studies have neglected these indirect pathways and their role in transmission. Here, we use rock ant colonies, a model social species whose flat nest geometry, coupled with individually tagged workers, allowed us to build temporally and spatially explicit interaction networks in which edges represent either direct physical contacts or indirect spatial coincidences. We show how the addition of indirect pathways allows the network to enhance or inhibit the spreading of different types of agent. This dual-functionality arises from an interplay between the interaction-strength distribution generated by the ants' movement and environmental decay characteristics of the spreading agent. These findings offer a general mechanism for understanding how interaction patterns might be tuned in animal societies to control the simultaneous transmission of harmful and beneficial agents. PMID:26400200

  2. Hospital contacts with infection and risk of schizophrenia: a population-based cohort study with linkage of Danish national registers.

    Science.gov (United States)

    Nielsen, Philip R; Benros, Michael E; Mortensen, Preben B

    2014-11-01

    Infections and immune responses have been suggested to play an important role in the etiology of schizophrenia. Several studies have reported associations between maternal infections during pregnancy and the child's risk of schizophrenia; however, infection during childhood and adolescence unrelated to maternal infection during pregnancy has not been studied to nearly the same extent and the results are far from conclusive. Data were drawn from 2 population-based registers, the Danish Psychiatric Central Register and the Danish National Hospital Register. We used a historical population-based cohort design and selected all individuals born in Denmark between 1981 and 1996 (n = 843 390). We identified all individuals with a first-time hospital contact with schizophrenia from 1991 through 2010. Out of the 3409 individuals diagnosed with schizophrenia, a total of 1549 individuals had had a hospital contact with infection before their schizophrenia diagnosis (45%). Our results indicate that individuals who have had a hospital contact with infection are more likely to develop schizophrenia (relative risk [RR] = 1.41; 95% CI: 1.32-1.51) than individuals who had not had such a hospital contact. Bacterial infection was the type of infection that was associated with the highest risk of schizophrenia (RR = 1.63; 95% CI: 1.47-1.82). Our study does not exclude that a certain type of infection may have a specific effect; yet, it does suggest that schizophrenia is associated with a wide range of infections. This association may be due to inflammatory responses affecting the brain or genetic and environmental risk factors aggregating in families.

  3. Dual contact pogo pin assembly

    Energy Technology Data Exchange (ETDEWEB)

    Hatch, Stephen McGarry

    2016-06-21

    A contact assembly includes a base and a pair of electrical contacts supported by the base. A first end of the first electrical contact corresponds to a first end of the base and is configured to engage a first external conductive circuit element. A first end of the second electrical contact also corresponds to the first end of the base and is configured to engage a second external conductive circuit element. The first contact and the second contact are electrically isolated from one another and configured to compress when engaging an external connector element. The base includes an aperture positioned on a second end of the base outboard of a second end of the first and second electrical contacts. The aperture presents a narrowing shape with a wide mouth distal the electrical contacts and a narrow internal through-hole proximate the electrical contacts.

  4. [Contact dermatitis in Dakar].

    Science.gov (United States)

    Niang, S O

    2007-01-01

    Because of the widespread repartition of allergens, allergic contact dermatitis is the most common inflammatory skin disease. It's the best model of dilated hypersensibility mediated by T lymphocytes cells. Atopic dermatitis and irritative dermatitis are to be distinguished to contact dermatitis. The aetiological diagnosis is the most important step of management of patients with that disease because it's the best way to avoid recurrences. The identification of cause is based on aetiological interrogatory and epicutaneous tests with 23 allergens completed with personnel products and specialised tests. Contact dermatitis can be classified according to results of aetiological management. In occupational contact dermatitis, contact dermatitis due to drugs, to metals, cosmetics, clothes and accessory and proteins. Management of patients with contact dermatitis is based on individual eviction, protection, cosmetovigilance, declaration of occupational dermatosis and allergovigilance. PMID:19102084

  5. Measuring energy efficiency: Is energy intensity a good evidence base?

    International Nuclear Information System (INIS)

    Highlights: • Energy intensity measure reflects consumption, not energy efficiency. • Thermodynamic indicators should describe energy efficiency at all levels. • These indicators should have no reference to economic or financial parameters. • A set of energy efficiency indicators should satisfy several basic principles. • There are trade-offs between energy efficiency, power and costs. - Abstract: There is a widespread assumption in energy statistics and econometrics that energy intensity and energy efficiency are equivalent measures of energy performance of economies. The paper points to the discrepancy between the engineering concept of energy efficiency and the energy intensity as it is understood in macroeconomic statistics. This double discrepancy concerns definitions (while engineering concept of energy efficiency is based on the thermodynamic definition, energy intensity includes economic measures) and use. With regard to the latter, the authors conclude that energy intensity can only provide indirect and delayed evidence of technological and engineering energy efficiency of energy conversion processes, which entails shortcomings for management and policymaking. Therefore, we suggest to stop considering subsectoral, sectoral and other levels of energy intensities as aggregates of lower-level energy efficiency. It is suggested that the insufficiency of energy intensity indicators can be compensated with the introduction of thermodynamic indicators describing energy efficiency at the physical, technological, enterprise, sub-sector, sectoral and national levels without references to any economic or financial parameters. Structured statistical data on thermodynamic efficiency is offered as a better option for identifying break-through technologies and technological bottle-necks that constrain efficiency advancements. It is also suggested that macro-level thermodynamic indicators should be based on the thermodynamic first law efficiency and the energy

  6. A study of the suitability of disposable coloured contact lenses for a South African clinic based population

    Directory of Open Access Journals (Sweden)

    V. R. Moodley

    2009-12-01

    Full Text Available Optometrists have always considered the fitting of all types of contact lenses to be an integral part of the scope of practice of their profession.  However, since the introduction of disposable cosmetic coloured contact lenses into the market, the frequency of over the counter sales of contact lenses has significantly increased.  Patients often present with contact lens complications at the University of Kwa-Zulu Natal clinic and local practices.  It is sometimes reported that the lenses were purchased over the counter, from an optometry practice or another non-registered vendor.  A common observation in these instances has been that the lenses do not fit optimally and that the incidence of complications associated with tight fitting lenses was much higher amongst the African patients as opposed to those of other race groups.  A clinical observational study utilizing convenience sampling of 240 subjects was undertaken to evaluate the fitting criteria of disposable cosmetic coloured contact lenses on a South African clinic based population.  All patients requesting the lenses chose their preferred colour and were fitted with Freshlook ColorBlends, Images or Expressions Colors lenses.  Lenses were evaluated after 20-25 minutes and then classified into tight, ideal or loose fits according to the lower lid push-up test, lenscentration, post blink movement and version lag and upgaze lens movements.  The ages of the subjects ranged from 16 to 45 years with a mean of 24.13 ± 5.66 years.  Seventy (29.2% were males and 170 (70.8% were females. The majority (62.9% of the lenses fitted on the subjects were rejected according to the fit criteria. The African subjects had the highest percentage of rejected fits (82.8% whilst 75% of the White subjects had acceptable fits.  The main reason for lens fits being rejected was that they displayed charac teristics of a tight fit (96% with only 4% of the fits being rejected due to being too loose. These

  7. Energy performance of windows based on the net energy gain

    DEFF Research Database (Denmark)

    Svendsen, Svend; Kragh, Jesper; Laustsen, Jacob Birck

    2005-01-01

    orientation or averaged over different orientations. The averaged value may be used for energy labeling of windows of standard size. Requirements in building codes may also be based on the net energy gain instead of the thermal transmittance of the window. The size and the configuration of the window, i.e....... number of glazing units, have a very large effect on the net energy gain. Therefore the energy labeling or the requirements based on the standard size may not give valid information on the energy performance of windows of non-standard size. The paper presents a method to set up requirements and classes...

  8. Non-contact wafer thickness measurement of capacitance sensor circuit based on CAV424

    Directory of Open Access Journals (Sweden)

    Yan You Jun

    2016-01-01

    Full Text Available Non-contact wafer thickness measurement with the CAV424 capacitance sensor special integrated circuit and arc pole plate capacitor sensor has good stability and linearity under low capacity of the bottom of sensor and low&entity; C condition. This method has a high technical advantages and practical value. Two capacitance sensors Cb, Ca measurement spacing 4mm install at the same axis which constitutes the size condition for measuring thickness. The static capacity of Ca and Cb is a constant value. The capacity of Cb and Ca will change when the silicon wafer is involved. This change is checked by the CAV424 capacitive sensor which has better linearity and higher thickness resolution.

  9. Epoxy Composite Based on Kenaf Fibers for Tribological Applications Under Wet Contact Conditions

    Science.gov (United States)

    Yousif, B. F.; Chin, C. W.

    2012-10-01

    In the current work, kenaf fibers reinforced epoxy (KFRE) composite was developed. Adhesive wear and frictional characteristics of KFRE were investigated under wet contact conditions at different fiber orientations, considering different applied loads (50-200 N) and sliding distances (0-30 km). Scanning electron microscopy (SEM) was used to observe the damages on the worn surfaces. The results revealed that fiber orientation plays a main role in determining the wear and frictional performance of the composites. Kenaf fibers, in normal orientation (N-O), enhanced the wear performance of the composite by about 35%-57%. It appears that the damages on the surface of the composite (N-O) were less than the other orientations (P-O and AP-O). Compared to previous work, KFRE has good potential of replacing glass fibers in tribological applications.

  10. Ion-track based single-channel templates for single-nanowire contacting

    Science.gov (United States)

    Chtanko, N.; Toimil-Molares, M. E.; Cornelius, T. W.; Dobrev, D.; Neumann, R.

    2005-07-01

    This work reports a procedure for the fabrication of membranes containing only one single channel with diameter down to 20 nm and with well-defined geometry. Foils of different types of polymer (polyethylene terephthalate (PET) and polycarbonate (PC)) were tested with respect to their suitability as ion-track template for single-nanowire growth. Membranes with one pore were created by the track-etching technique. The pore size was characterized by electrical conductivity measurements in 1 M KCl. Furthermore, we developed also a method for the preparation and electrical contacting of single metallic nanowires. Cylindrical single pores were filled with Bi by electrochemical deposition. The resulting wires, remaining embedded in the polymer foil, are very suitable for measurements of electrical resistance as a function of parameters such as wire diameter and temperature.

  11. A highly selective solid-contact electrode for Ag+ based on a monoazathiacrown ether ionophore

    Institute of Scientific and Technical Information of China (English)

    Shun Yang Yu; Lan Ju; Fu Hai Li; Yong Ming Liu; Jun Feng Fang

    2012-01-01

    A new solid-contact Ag+-selective electrode was prepared with 9,10,12,13,24,25-hexahydro-5H,15H,23H-dibenzo[b,q][1,7,10,13,19,4,16]-entathiadiazacyclodocosine-6,16(7H,17H)-dione as ionophore,and α,ω-dihexylsexithiophene (DH6T) ion-to-electron transducer.The sensor exhibited a working concentration range of 10-8 to 10-3 mol/L,with a near-Nernstian slope of 55.1 ± 0.2 mV/dec and detection limit of 1.7 × 10-9 mol/L.The fabricated electrodes demonstrated excellent selectivity over the most common monovalent and divalent cations.

  12. Point contact resistive switching memory based on self-formed interface of Al/ITO

    Science.gov (United States)

    Li, Qiuhong; Qiu, Linjun; Wei, Xianhua; Dai, Bo; Zeng, Huizhong

    2016-07-01

    Point contact resistive switching random access memory (RRAM) has been achieved by directly sputtering Al electrodes on indium tin oxide (ITO) conductive glasses. The room-temperature deposited Al/ITO shows an asymmetrical bipolar resistive switching (BRS) behavior after a process of initialization which induces a stable high resistive state (HRS). It might be caused by the in-situ formation of an ultra-thin layer (≈4 nm) at the interface. By comparison, the Al/ITO device after vacuum annealed exhibits typical symmetrical BRS without an initiation or electroforming process. This can be ascribed to the ex-situ thickening of the interfacial layer (≈9.2 nm) to achieve the stable HRS after heat treatment. This work suggests that the self-formed interface of active Al electrode/ITO would provide the simplest geometry to construct RRAM.

  13. Research on arc erosion of silver-based alloy contact materials under low voltage,resistive load and small current at 400 Hz and 50 Hz

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    By using a self-developed IF power and a ASTM contact material experimental system of small-capacity and variable frequency,the value of arcing characteristics and the welding force of the silver-based contact material are acquired under low voltage,resistive load and small current at 400 Hz and 50 Hz. By means of an electricity-ray analytical balance,SEM and EDAX,the weighing values of the contact materials and the changes of AgCdO,AgNi,AgC and AgW contact material surface profile and micro-area constituen...

  14. Diamond Film Synthesis with a DC Plasma Jet:Effect of the Contacting Interface between Substrate and Base on the Substrate Temperature

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The contacting interface between the substrate and water-cooled base is vital to the substrate temperature during diamond films deposition by a DC (direct current) plasma jet. The effects of the solid contacting area,conductive materials and fixing between the substrate and the base were investigated without affecting the other parameters. Experimental results indicated that the preferable solid contacting area was more than 60% of total contacting areal; the particular Sn-Pb alloy was more suitable for conducting heat and the concentric fixing ring was a better setting for controlling the substrate temperature. The result was explained in terms of the variable thermal contact resistance at the interface between substrate and base. The diamond films were analyzed by scanning electron microscopy (SEM) for morphology, X-ray diffraction (XRD) for the intensity of characteristic spectroscopy and Raman spectroscopy for structure.

  15. Data on face-to-face contacts in an office building suggests a low-cost vaccination strategy based on community linkers

    CERN Document Server

    Génois, Mathieu; Fournet, Julie; Panisson, André; Bonmarin, Isabelle; Barrat, Alain

    2014-01-01

    Empirical data on contacts between individuals in social contexts play an important role in the information of models describing human behavior and how epidemics spread in populations. Here, we analyze data on face-to-face contacts collected in an office building. The statistical properties of contacts are similar to other social situations, but important differences are observed in the contact network structure. In particular, the contact network is strongly shaped by the organization of the offices in departments, which has consequences in the design of accurate agent-based models of epidemic spread. We then consider the contact network as a potential substrate for infectious disease spread and show that its sparsity tends to prevent outbreaks of fast-spreading epidemics. Moreover, we define three typical behaviors according to the fraction $f$ of links each individual shares outside its own department: residents, wanderers and linkers. Linkers ($f\\sim 50%$) act as bridges in the network and have large betw...

  16. Ultracoatings: Enabling Energy and Power Solutions in High Contact Stress Environments through next-generation Nanocoatings Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Clifton B. Higdon III

    2012-03-20

    . Advancing this technology, called Ultracoatings, through initial development, scale up, and commercialization to a variety of markets would represent a transformative leap to surface engineering. Several application spaces were considered for immediate implementation of the Ultracoatings technology, including, but not limited to, a drive shaft for an aerospace fuel pump, engine timing components, and dry solids pump hardware for an innovative coal gasifier. The primary focus of the program was to evaluate and screen the performance of the selected (Ti, Zr)B2 Ultracoatings composition for future development. This process included synthesis of the material for physical vapor deposition, sputtering trials and coating characterization, friction and wear testing on sample coupons, and functional hardware testing. The main project deliverables used to gage the project's adherence to its original objective were: Development of a coating/substrate pairing that exhibits wear rate of 0.1 mg/hour or lower at a 1GPa contact pressure, while achieving a maximum coating cost of $0.10/cm2. Demonstrate the aforementioned wear rate in both lubricated and starved lubrication conditions. Although the (Ti, Zr) B2 coating was not tailored for low friction performance, friction and wear evaluations of the material demonstrated a coefficient of sliding friction as low as 0.09. This suggests that varying the percentage of TiB2 present in the composite could enhance the materials performance in water-based lubricants. In the aerospace drive shaft application, functional hardware coated with (Ti, Zr)B2 survived a variety of abuse and long-range durability tests, with contact pressures exceeding 2 GPa. For engine timing components, further work is planned to evaluate the Ultracoatings technology in direct injection and diesel engine conditions. In the final identified application space the dry solids pump hardware, discussions continue on the application of the Ultracoatings technology for those

  17. Contact-based model for strategy updating and evolution of cooperation

    Science.gov (United States)

    Zhang, Jianlei; Chen, Zengqiang

    2016-06-01

    To establish an available model for the astoundingly strategy decision process of players is not easy, sparking heated debate about the related strategy updating rules is intriguing. Models for evolutionary games have traditionally assumed that players imitate their successful partners by the comparison of respective payoffs, raising the question of what happens if the game information is not easily available. Focusing on this yet-unsolved case, the motivation behind the work presented here is to establish a novel model for the updating of states in a spatial population, by detouring the required payoffs in previous models and considering much more players' contact patterns. It can be handy and understandable to employ switching probabilities for determining the microscopic dynamics of strategy evolution. Our results illuminate the conditions under which the steady coexistence of competing strategies is possible. These findings reveal that the evolutionary fate of the coexisting strategies can be calculated analytically, and provide novel hints for the resolution of cooperative dilemmas in a competitive context. We hope that our results have disclosed new explanations about the survival and coexistence of competing strategies in structured populations.

  18. Developments in nano-oscillators based upon spin-transfer point-contact devices

    Science.gov (United States)

    Silva, T. J.; Rippard, W. H.

    We review the current status of research on microwave nano-oscillators that utilize spin transfer devices with point-contact geometry, with an emphasis on the open questions that still prevent our full understanding of device properties. In particular, we examine those aspects that might affect irreproducibility of device performance. While there is a clear picture of the general principles that underlie the properties of the spin torque nano-oscillator, there are a number of details complicating the picture. We suggest that these details are potentially responsible for adversely affecting uniformity of performance from device to device. These details include (1) nonlinearities, (2) the Oersted field, (3) thermal and deterministic noise sources, and (4) non-uniformity of the spin accumulation. We suggest what role that these details might have in determining spin torque dynamics, and suggest particular avenues of investigation that might clarify whether or not these details are indeed responsible for device variability. This article is one of a series devoted to the subject of spin torque in this issue of the Journal of Magnetism and Magnetic Materials.

  19. Fundamental characterization of shrink techniques on negative tone development based dense contact holes

    Science.gov (United States)

    Jain, Kaveri; Light, Scott L.

    2016-03-01

    Enormous advances have been made in recent years to design sub 40nm dense contact hole pattern with local CD uniformity (CDU) that the process can tolerate. Negative tone development process (NTD) on 193nm photoresists has achieved this to a large extent without the requirement of additional processing steps on the patterned layer. With further shrinking of size of the subsequent nodes, the demand to produce smaller patterns with wider process window, low defectivity, and improved CDU is increasing, and reaching beyond what can be achieved through NTD alone. A number of techniques are in practice today to achieve this, most notably, implementation of a collar of Atomic Layer Deposited SiO2 (ALD) on photoresist or substrate. However, in recent years, various material suppliers have also proposed shrink chemistries to achieve this. In this paper, we have provided fundamental characterization of shrink via application of spin-on agents (organic as well as aqueous) on the post-imaged pattern. We have also compared them for their shrink capacity, defect tendency, dry etch capability and ease of implementation in the process flow. In addition, we have provided recommendations on which technique is suitable for a given set of process prerequisites.

  20. Research on arc erosion of silver-based alloy contact materials under low voltage, resistive load and small current at 400 Hz and 50 Hz

    Institute of Scientific and Technical Information of China (English)

    Jing Li; Zhi-ying Ma

    2009-01-01

    By using a self-developed IF power and a ASTM contact material experimental system of small-capacity and variable frequency, the value of arcing characteristics and the welding force of the silver-based contact material are acquired under low voltage, resistive load and small current at 400 Hz and 50 Hz. By means of an electricity-ray analytical balance, SEM and EDAX, the weighing values of the contact materials and the changes of AgCdO, AgNi, AgC and AgW contact material surface profile and micro-area constituent are obtained and analyzed. The arc erosion causes of silver-based alloy contact materials at 400 Hz and 50 Hz are also discussed.

  1. Sensing with Superconducting Point Contacts

    Directory of Open Access Journals (Sweden)

    Argo Nurbawono

    2012-05-01

    Full Text Available Superconducting point contacts have been used for measuring magnetic polarizations, identifying magnetic impurities, electronic structures, and even the vibrational modes of small molecules. Due to intrinsically small energy scale in the subgap structures of the supercurrent determined by the size of the superconducting energy gap, superconductors provide ultrahigh sensitivities for high resolution spectroscopies. The so-called Andreev reflection process between normal metal and superconductor carries complex and rich information which can be utilized as powerful sensor when fully exploited. In this review, we would discuss recent experimental and theoretical developments in the supercurrent transport through superconducting point contacts and their relevance to sensing applications, and we would highlight their current issues and potentials. A true utilization of the method based on Andreev reflection analysis opens up possibilities for a new class of ultrasensitive sensors.

  2. Development of ZnO:Al-based transparent contacts deposited at low-temperature by RF-sputtering on InN layers

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, S. [Departamento de Energias Renovables, Energia Solar Fotovoltaica, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, 28040 Madrid (Spain); Naranjo, F.B.; Valdueza-Felip, S. [Grupo de Ingenieria Fotonica, Departamento de Electronica, Escuela Politecnica Superior, Universidad de Alcala Campus Universitario, 28871 Alcala de Henares, Madrid (Spain); Abril, O. de [ISOM and Departamento de Fisica Aplicada, Escuela Tecnica Superior de Ingenieros de Telecomunicacion, Universidad Politenica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2012-03-15

    Nitride semiconductors (Al,Ga,In)N attain material properties that make them suitable for photovoltaic and optoelectronics devices to be used in hard environments. These properties include an energy gap continuously tuneable within the energy range of the solar spectrum, a high radiation resistance and thermal stability. The developing of efficient devices requires contacts with low resistivity and high transmittance in visible region. ZnO:Al (AZO) emerges as a feasible candidate for transparent contact to nitride semiconductors, taking advantage of its low resistivity, high transparency in visible wavelengths and a very low lattice mismatch with respect to nitride semiconductors. This work presents a study of the applications of AZO films deposited at low-temperature by RF magnetron sputtering as transparent contact for InN layers. The optimization of AZO conditions deposition lead to the obtaining of contacts which shows an ohmic behaviour for the as-deposited layer, regardless the thickness of the ZnO:Al contact layer. Specific contact resistances of 1.6 {omega}.cm{sup 2} were achieved for the contact with 90 nm thick ZnO:Al layer without any post-deposition treatment (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. MATHEMATIC MODEЕLING OF NONLINEAR-INELASTIC BASE-FOUNDATION CONTACT PROBLEM

    Directory of Open Access Journals (Sweden)

    TIMCHENKO R. O.

    2015-12-01

    Full Text Available Raising of problem.Calculation of buildings, that isn’t carrying non-uniform deformation, is going to definition of foundation displacement and calculation of their elements hardness and sustainability. In that case we don’t pay attention on building and base cooperative deformations. Another view we can see in case of building calculation with hard geological conditions. Base of such buildings is uneven compressible soils or displacement carrying soil. Calculation of these constructions is impossible without building and base mutual influence consideration. One of the most important calculation parameters in cooperative deformation equations is base stiffness factor. Purpose. Purpose is to define peculiar properties of self-regulation foundation calculation in case of non-uniform base deformation by the variable base stiffness factor. Conclusion. Analysis of modern construction calculation methods with deformation soil properties demonstrated that variable base stiffness factor method employment is the most reasonable for solution of undermined base and foundation interaction problem. Besides, we need to take into account variable base stiffness factor decrease depended on relative horizontal extension deformation value. Nonlinear-inelastic soil diagram application for calculation of construction with hard geological conditions lead to main deformation 50% decrease compared with elastic calculation depended on “base – foundation – building” structure stiffness.

  4. Contact dermatitis

    Science.gov (United States)

    ... type. It can be by contact with acids, alkaline materials such as soaps and detergents , fabric softeners, ... dyes, and permanent wave solutions Nickel or other metals (found in jewelry, watch straps, metal zips, bra ...

  5. Contact problems

    CERN Document Server

    Galin, Lev Aleksandrovich

    2008-01-01

    L.A. Galin's book on contact problems is a remarkable work. Actually there are two books: the first, published in 1953 deals with contact problems in the classical theory of elasticity; this is the one that was translated into English in 1961. The second book, published in 1980, included the first, and then had new sections on contact problems for viscoelastic materials, and rough contact problems; this section has not previously been translated into English. In this new translation, the original text and the mathematical analysis have been completely revised, new material has been added, and the material appearing in the 1980 Russian translation has been completely rewritten. In addition there are three essays by students of Galin, bringing the analysis up to date.

  6. A soft-contact and wrench based approach to study grasp planning and execution.

    Science.gov (United States)

    Singh, Tarkeshwar; Ambike, Satyajit

    2015-11-01

    Grasping research in robotics has made remarkable progress in the last three decades and sophisticated computational tools are now available for planning robotic grasping in complex environments. However, studying the neural control of prehension in humans is more complex than studying robotic grasping. The elaborate musculoskeletal geometries and complex neural inputs to the hand facilitate a symphonic interplay of power and precision that allows humans to grasp fragile objects in a stable way without either crushing or dropping them. Most prehension studies have focused on a planar simplification of prehension since planar analyses render the complex problem of prehension tractable with few variables. The caveat is that planar simplification allows researchers to ask only a limited set of questions. In fact, one of the problems with extending prehension studies to three dimensions is the lack of analytical tools for quantifying features of spatial prehension. The current paper provides a theoretical adaptation and a step-by-step implementation of a widely used soft-contact wrench model for spatial human prehension. We propose two indices, grasp caliber and grasp intensity, to quantitatively relate digit placement and digit forces to grasp stability. Grasp caliber is the smallest singular value of the grasp matrix and it indicates the proximity of the current grasp configuration to instability. Grasp intensity is the magnitude of the excessive wrench applied by the digits to counter perturbations. Apart from quantifying stability of spatial grasps, these indices can also be applied to investigate sensory-motor coupling and the role of perception in grasp planning. PMID:26475219

  7. A soft-contact and wrench based approach to study grasp planning and execution.

    Science.gov (United States)

    Singh, Tarkeshwar; Ambike, Satyajit

    2015-11-01

    Grasping research in robotics has made remarkable progress in the last three decades and sophisticated computational tools are now available for planning robotic grasping in complex environments. However, studying the neural control of prehension in humans is more complex than studying robotic grasping. The elaborate musculoskeletal geometries and complex neural inputs to the hand facilitate a symphonic interplay of power and precision that allows humans to grasp fragile objects in a stable way without either crushing or dropping them. Most prehension studies have focused on a planar simplification of prehension since planar analyses render the complex problem of prehension tractable with few variables. The caveat is that planar simplification allows researchers to ask only a limited set of questions. In fact, one of the problems with extending prehension studies to three dimensions is the lack of analytical tools for quantifying features of spatial prehension. The current paper provides a theoretical adaptation and a step-by-step implementation of a widely used soft-contact wrench model for spatial human prehension. We propose two indices, grasp caliber and grasp intensity, to quantitatively relate digit placement and digit forces to grasp stability. Grasp caliber is the smallest singular value of the grasp matrix and it indicates the proximity of the current grasp configuration to instability. Grasp intensity is the magnitude of the excessive wrench applied by the digits to counter perturbations. Apart from quantifying stability of spatial grasps, these indices can also be applied to investigate sensory-motor coupling and the role of perception in grasp planning.

  8. First Contact: interprofessional education based on medical students' experiences from their nursing internship

    Directory of Open Access Journals (Sweden)

    Eich-Krohm, Astrid

    2016-04-01

    Full Text Available Goal: The aim of the course “interprofessional communication and nursing” is to reflect medical students’ experiences from the nursing internship. The content of the course focuses on barriers and support of interprofessional communication as a foundation for teamwork between nursing professionals and physicians. The nursing internship is for most medical students the first contact with nursing professionals and can lead to perceptions about the other group that might hinder interprofessional teamwork and consequently harm patients. To meet the demographic challenges ahead it is important to emphasize interprofessional education in the study of medicine and better prepare future physicians for interprofessional collaboration. Method: The design of the course includes an assessment of a change in the students’ perceptions about nursing and interprofessional communication. The first class meeting presents the starting point of the assessment and visualizes students’ perceptions of nursing and medicine. The content of the following class meetings serve to enhance the students’ knowledge about nursing as a profession with its own theories, science and scholarship. In addition, all students have to write a research paper that entails to interview one nursing professional and one physician about their ideas of interprofessional communication and to compare the interviews with their own experiences from the nursing internship. To access what students learned during the course a reflective discussion takes place at the last meeting combined with an analysis of the students’ research papers. Results: The assessment of the students’ perceptions about the nursing profession and the importance of successful interprofessional communication showed a new and deeper understanding of the topic. They were able to identify barriers and support measures of interprofessional communication and their own responsibilities as part of a team

  9. Contact materials for nanoelectronics

    KAUST Repository

    Alshareef, Husam N.

    2011-02-01

    In this article, we review current research activities in contact material development for electronic and nanoelectronic devices. A fundamental issue in contact materials research is to understand and control interfacial reactions and phenomena that modify the expected device performance. These reactions have become more challenging and more difficult to control as new materials have been introduced and as device sizes have entered the deep nanoscale. To provide an overview of this field of inquiry, this issue of MRS Bulletin includes articles on gate and contact materials for Si-based devices, junction contact materials for Si-based devices, and contact materials for alternate channel substrates (Ge and III-V), nanodevices. © 2011 Materials Research Society.

  10. Physically-based simulation of zinc oxide thin-film transistors: Contact resistance contribution on density of states

    Science.gov (United States)

    Dominguez, Miguel A.; Alcantara, Salvador; Soto, Susana

    2016-06-01

    In this work, using a physically-based simulator, the density of states DOS is modeled to reproduce the experimental electrical characteristics of ZnO TFTs fabricated by Ultrasonic Spray Pyrolysis at 200 °C. The contact resistance was experimentally extracted from the ZnO TFTs and included into the simulation, in order to separate the metal-semiconductor interface contribution from the DOS. A comparison between the modeled DOS considering the contact resistance and disregarding it is also presented. It is proposed to consider the acceptor-like states and the tail-donor states, where the deep-acceptor states have approximately an exponential form and the distribution of tail-acceptor states are sharper than the distribution of tail-donor states. The simulated electrical characteristics reproduce very well the experimental data at different channel lengths. The use of physically-based simulation can be useful to model the DOS of Oxide semiconductor films in TFTs by reproducing the experimental data.

  11. LCA of biomass-based energy systems

    DEFF Research Database (Denmark)

    Tonini, Davide; Astrup, Thomas Fruergaard

    2012-01-01

    on the reference year 2008, energy scenarios for 2030 and 2050 were assessed. For 2050 three alternatives for supply of transport fuels were considered: (1) fossil fuels, (2) rapeseed based biodiesel, and (3) Fischer–Tropsch based biodiesel. Overall, the results showed that greenhouse gas emissions per PJ energy......Decrease of fossil fuel consumption in the energy sector is an important step towards more sustainable energy production. Environmental impacts related to potential future energy systems in Denmark with high shares of wind and biomass energy were evaluated using life-cycle assessment (LCA). Based...... environmental impacts in the 2050 scenarios, in particular upstream impacts from land use changes (LUCs), fertilizer use and NOx emissions from the transport sector were critical. Land occupation (including LUC effects) caused by energy crop production increased to a range of 600–2100 × 106 m2/PJ depending...

  12. First-principles investigation on the electronic efficiency and binding energy of the contacts formed by graphene and poly-aromatic hydrocarbon anchoring groups

    International Nuclear Information System (INIS)

    The electronic efficiency and binding energy of contacts formed between graphene electrodes and poly-aromatic hydrocarbon (PAH) anchoring groups have been investigated by the non-equilibrium Green’s function formalism combined with density functional theory. Our calculations show that PAH molecules always bind in the interior and at the edge of graphene in the AB stacking manner, and that the binding energy increases following the increase of the number of carbon and hydrogen atoms constituting the PAH molecule. When we move to analyzing the electronic transport properties of molecular junctions with a six-carbon alkyne chain as the central molecule, the electronic efficiency of the graphene-PAH contacts is found to depend on the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the corresponding PAH anchoring group, rather than its size. To be specific, the smaller is the HOMO-LUMO gap of the PAH anchoring group, the higher is the electronic efficiency of the graphene-PAH contact. Although the HOMO-LUMO gap of a PAH molecule depends on its specific configuration, PAH molecules with similar atomic structures show a decreasing trend for their HOMO-LUMO gap as the number of fused benzene rings increases. Therefore, graphene-conjugated molecule-graphene junctions with high-binding and high-conducting graphene-PAH contacts can be realized by choosing appropriate PAH anchor groups with a large area and a small HOMO-LUMO gap

  13. Effect of contact interface configuration on electronic transport in (C{sub 20}){sub 2}-based molecular junctions

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Guomin; Li, Dongmei; Fang, Changfeng; Xu, Yuqing [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Zhai, Yaxin [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112-0830 (United States); Cui, Bin [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Liu, Desheng, E-mail: liuds@sdu.edu.cn [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Department of Physics, Jining University, Qufu 273155 (China)

    2012-01-16

    Using first-principles calculations, we study the electronic transport properties in Au-(C{sub 20}){sub 2}-Au molecular junctions with different contact interface configurations: point contact and bond contact. We observe that the transmission through the bond contact is considerably higher than that of point contact. Furthermore, the I–V characteristics are rather different. For the bond contact, we get a metallic behavior followed by a varistor-type behavior. While as for the point contact, the current increases very slowly in a nonlinear way and is one order of magnitude smaller than that of bond contact. We attribute these obvious differences to the distinct contact configurations. -- Highlights: ► The I–V properties of (C{sub 20}){sub 2} molecular devices are affected by contact configuration. ► As for the bond contact, metallic behavior in the low bias is observed. ► Varistor-type behavior and nonlinear I–V characteristic in the high bias are found. ► As for the point contact, the Landauer conductance greatly decreases. ► The current is one order of magnitude smaller than that of bond contact.

  14. THE INVESTIGATION OF CONTACT RESISTANCE CHARACTERISTICS ON ELECTRICAL CONTACTS USED IN COAL MINES

    Institute of Scientific and Technical Information of China (English)

    郭凤仪; 王其平; 孙鹤旭; 乔和; 张静

    1997-01-01

    Based on the electrical contact and arc theory, the experiments on contact resistance characteristics of electrical contacts are carried out, by analyzing the experimental results, some conclusions of contact resistance characteristics have been obtained in this paper.

  15. 基于半赫兹接触的车轮磨耗计算%Calculation of Wheel Wear Based on Semi-Hertzian Contact

    Institute of Scientific and Technical Information of China (English)

    丁军君; 李芾; 黄运华

    2011-01-01

    为了分析轮轨接触模型对车轮磨耗计算的影响,基于半赫兹接触、赫兹接触和Kalker完全理论程序CONTACT分别计算轮轨接触应力和接触斑形状,并在Kalker简化理论基础上求解半赫兹接触的蠕滑力;基于Archard磨耗模型,计算车轮磨耗深度在踏面上的分布.计算结果表明:由于半赫兹接触考虑了接触斑内曲率的变化,则接触斑形状和最大接触应力比赫兹接触更接近于CONTACT计算结果;在大自旋蠕滑工况下,应用半赫兹接触得到的横向蠕滑力与CONTACT计算结果有较大偏差,其余工况相差不超过18%;基于半赫兹接触的FASTSIM计算时间约为基于赫兹接触的6倍,是CONTACT计算时间的1/166;半赫兹接触时,考虑弹性滑动速度的车轮磨耗深度更接近于CONTACT计算结果.%To study the effect of wheel/rail contact theory on wheel wear calculation, wheel/rail contact stress and contact patch were analyzed using the semi-Hertzian contact theory, the Hertzian contact theory and the CONTACT program of Kalker's exact theory. Then, the creep forces under semi-Hertzian contact were solved by Kalker's simplified theory using the numerical program FASTSIM, and the wear depths of wheel profile were calculated based on Archard wear model. The results indicate that the contact patch and maximal contact stress calculated by semi-Hertzian theory are more closer to CONTACTS than that by Hertzian theory, because the varied curvatures in contact patch are considered in the semi-Hertzian theory; the error of creep forces between semi-Hertzian theory and CONTACT does not exceed 18% , except the lateral creep force in large spin creep condition; the computing time of the FASTSIM algorithm based on semi-Hertzian theory is 6 times that based on Hertzian theory and 1/166 of the CONTACTS; and, the wheel wear depth calculated by semi-Hertzian theory agrees well with CONTACTS when the elastic velocity is considered.

  16. Integrated energy systems based on cascade utilization of energy

    Energy Technology Data Exchange (ETDEWEB)

    Jin Hongguang; Gao Lin; Han Wei; Li Bingyu; Feng Zhibing [Chinese Academy of Sciences, Beijing (China). Institute of Engineering Thermophysics

    2007-02-15

    Focusing on the traditional principle of physical energy utilization, new integration concepts for combined cooling, heating and power (CCHP) system were identified, and corresponding systems were investigated. Furthermore, the principle of cascade utilization of both chemical and physical energy in energy systems with the integration of chemical processes and thermal cycles was introduced, along with a general equation describing the interrelationship among energy levels of substance, Gibbs free energy of chemical reaction and physical energy. On the basis of this principle, a polygeneration system for power and liquid fuel (methanol) production has been presented and investigated. This system innovatively integrates a fresh gas preparation subsystem without composition adjustment process (NA) and a methanol synthesis subsystem with partial-recycle scheme (PR). Meanwhile, a multi-functional energy system (MES) that consumes coal and natural gas as fuels simultaneously, and co-generates methanol and power, has been presented. In the MES, coal and natural gas are utilized synthetically based on the method of dual-fuel reforming, which integrates methane/steam reforming and coal combustion. Compared with conventional energy systems that do not consider cascade utilization of chemical energy, both of these systems provide superior performance, whose energy saving ratio can be as high as 10%-15%. With special attention paid to chemical energy utilization, the integration features of these two systems have been revealed, and the important role that the principle of cascade utilization of both chemical and physical energy plays in system integration has been identified.

  17. Contact Center Manager Administration (CCMA)

    Data.gov (United States)

    Social Security Administration — CCMA is the server that provides a browser-based tool for contact center administrators and supervisors. It is used to manage and configure contact center resources...

  18. The French Connection: The First Large Population-Based Contact Survey in France Relevant for the Spread of Infectious Diseases.

    Directory of Open Access Journals (Sweden)

    Guillaume Béraud

    Full Text Available Empirical social contact patterns are essential to understand the spread of infectious diseases. To date, no such data existed for France. Although infectious diseases are frequently seasonal, the temporal variation of contact patterns has not been documented hitherto.COMES-F is the first French large-scale population survey, carried out over 3 different periods (February-March, April, April-May with some participants common to the first and the last period. Participants described their contacts for 2 consecutive days, and reported separately on professional contacts when typically over 20 per day.2033 participants reported 38 881 contacts (weighted median [first quartile-third quartile]: 8[5-14] per day, and 54 378 contacts with supplementary professional contacts (9[5-17]. Contrary to age, gender, household size, holidays, weekend and occupation, period of the year had little influence on the number of contacts or the mixing patterns. Contact patterns were highly assortative with age, irrespective of the location of the contact, and gender, with women having 8% more contacts than men. Although most contacts occurred at home and at school, the inclusion of professional contacts modified the structure of the mixing patterns. Holidays and weekends reduced dramatically the number of contacts, and as proxies for school closure, reduced R0 by 33% and 28%, respectively. Thus, school closures could have an important impact on the spread of close contact infections in France.Despite no clear evidence for temporal variation, trends suggest that more studies are needed. Age and gender were found important determinants of the mixing patterns. Gender differences in mixing patterns might help explain gender differences in the epidemiology of infectious diseases.

  19. The Degradation Interface of Magnesium Based Alloys in Direct Contact with Human Primary Osteoblast Cells

    OpenAIRE

    Ahmad Agha, Nezha; Willumeit-Römer, Regine; Laipple, Daniel; Luthringer, Bérengère; Feyerabend, Frank

    2016-01-01

    Magnesium alloys have been identified as a new generation material of orthopaedic implants. In vitro setups mimicking physiological conditions are promising for material / degradation analysis prior to in vivo studies however the direct influence of cell on the degradation mechanism has never been investigated. For the first time, the direct, active, influence of human primary osteoblasts on magnesium-based materials (pure magnesium, Mg-2Ag and Mg-10Gd alloys) is studied for up to 14 days. Se...

  20. Physical Model of the Slide Guitar: An Approach Based on Contact Forces

    OpenAIRE

    Evangelista, Gianpaolo

    2012-01-01

    In this paper we approach the synthesis of the slide guitar, which is a particular play mode of the guitar where continuous tuning of the tones is achieved by sliding a metal orglass piece, the bottleneck, along thestrings on the guitar neck side. The bottleneck constitues a unilateral constraint for the string vibration.Dynamics is subject to friction, scraping, textured displacement and collisions. The presented model is physically inspired and is based on a dynamic model of friction, toget...

  1. Performance Analysis of Leaf Spring by Contact Mechanics Approach Based on the Nature of Material Properties

    OpenAIRE

    Sathish Gandhi, Veeramalai Chinnasamy; Kumaravelan, Radhakrishnan; Ramesh, Sengottuvelu; Joemax Agu, Maxwell Thompson

    2014-01-01

    In an automotive system, a curved leaf spring is used for the purpose of suspension and for reducing the transient vibration of the system. Composite materials are widely used in automobile industries as a replacement for steel to reduce the weight and to increase the strength of an automotive system. In this study, various materials have been considered for an analysis based on the Young modulus-to-yield strength ratio. The study has been carried out by considering the material properties. T...

  2. Contact of surfaces and contact characteristics of offset surfaces

    Institute of Scientific and Technical Information of China (English)

    Lixin CAO; Hu GONG; Jian LIU

    2008-01-01

    Based on differential geometry, the contact problems of two surfaces are discussed in this paper. The relationship between the contact status of two sur-faces and that of offset surfaces are also analyzed. For a 5-axis NC machining, some research such as optimization of cutter location and calculation of the geometrical cusp height are important. The research results indicate that the relative normal curvature is an important geometrical invariant for describing the contact state of two surfaces. For point contact two surfaces, the calculation equation for the second order remained error is given. For line contact two surfaces, the condition of the second order line contact is that the principal directions and curvatures of the two surfaces are the same along the contact curve. If two surfaces keep the second order line contact, their two offset surfaces will also keep the second order line contact, and their third order remained errors are also uniform with that of the two offset surfaces.

  3. Graphene-based materials for energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, Nanda Gopal [Energy Research Institute, Nanyang Technological University (Singapore); Pan, Yongzheng; Li, Lin; Chan, Siew Hwa [School of Mechanical and Aerospace Engineering, Nanyang Technological University (Singapore)

    2012-08-08

    With the depletion of conventional energy sources, the demand for renewable energy and energy-efficient devices continues to grow. As a novel 2D nanomaterial, graphene attracts considerable research interest due to its unique properties and is a promising material for applications in energy conversion and storage devices. Recently, the fabrication of fuel cells and solar cells using graphene for various functional parts has been studied extensively. This research news summarizes and compares the advancements that have been made and are in progress in the utilization of graphene-based materials for energy conversion. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Differential Laser Doppler based Non-Contact Sensor for Dimensional Inspection with Error Propagation Evaluation

    Directory of Open Access Journals (Sweden)

    Ketsaya Vacharanukul

    2006-06-01

    Full Text Available To achieve dynamic error compensation in CNC machine tools, a non-contactlaser probe capable of dimensional measurement of a workpiece while it is being machinedhas been developed and presented in this paper. The measurements are automatically fedback to the machine controller for intelligent error compensations. Based on a well resolvedlaser Doppler technique and real time data acquisition, the probe delivers a very promisingdimensional accuracy at few microns over a range of 100 mm. The developed opticalmeasuring apparatus employs a differential laser Doppler arrangement allowing acquisitionof information from the workpiece surface. In addition, the measurements are traceable tostandards of frequency allowing higher precision.

  5. Contact Dermatitis

    Science.gov (United States)

    ... resources Meet our partners Español Donate Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases ... Contact dermatitis public SPOT Skin Cancer™ Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases ...

  6. Dry contact fingertip ECG-based authentication system using time, frequency domain features and support vector machine.

    Science.gov (United States)

    Singh, Karan; Singhvi, Akshit; Pathangay, Vinod

    2015-08-01

    Acquiring fingertip ECG (electrocardiogram) signal using dry contact electrodes is challenging due to the presence of noise and interference by EMG (electromyogram) potentials. In this paper, we propose a method for using the fingertip ECG signal for biometric authentication. The noisy segments of the signal are segmented out using a variance-based heuristic and the clean signal is used for subsequent processing. By applying baseline correction and band pass filtering, the filtered signal is used for beat feature extraction. The features are used to train a support vector machine (SVM) classifier. Experimental results are presented to show the optimum filter parameters and feature sets for best classification performance. The performance of the proposed method with the optimum parameters was evaluated on a public domain CYBHi dataset with 126 subjects and the beat level EER of 3.4% was obtained.

  7. Fabrication of four-point biped robot foot module based on contact-resistance force sensor and its evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hyun Joon; Kim, Jong Ho; Kim, Dong Ki [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Kwon, Young Ha [Kyung Hee University, Yongin (Korea, Republic of)

    2011-02-15

    This paper presents the design of robot foot module of four-point biped walking robot and its fabrication. The foot module has four sensor units based on contact-resistance force sensor. The thin-film-type force sensor is fabricated by coating resistive ink on thin polyimide film using silk screening technique. The simple structure is devised and fabricated to assemble the thin force sensor rigidly. The unit force sensor module is evaluated by the calibration setup to obtain the characteristics of repeatability and hysteresis. The sensor module presents hysteresis error of about 5% and repeatability error of about 0.37%. The calculated zero moment point (ZMP) of the foot module is also compared with the measured position using static load of 50 N. The maximum location error of ZMP is less than 10%. The robot foot module shows the possibility of applying it to humanoid walking.

  8. Non-Contact Analysis of the Adsorptive Ink Capacity of Nano Silica Pigments on a Printing Coating Base

    Science.gov (United States)

    Jiang, Bo; Huang, Yu Dong

    2014-01-01

    Near infrared spectra combined with partial least squares were proposed as a means of non-contact analysis of the adsorptive ink capacity of recording coating materials in ink jet printing. First, the recording coating materials were prepared based on nano silica pigments. 80 samples of the recording coating materials were selected to develop the calibration of adsorptive ink capacity against ink adsorption (g/m2). The model developed predicted samples in the validation set with r2  = 0.80 and SEP  = 1.108, analytical results showed that near infrared spectra had significant potential for the adsorption of ink capacity on the recording coating. The influence of factors such as recording coating thickness, mass ratio silica: binder-polyvinyl alcohol and the solution concentration on the adsorptive ink capacity were studied. With the help of the near infrared spectra, the adsorptive ink capacity of a recording coating material can be rapidly controlled. PMID:25329464

  9. Dry contact fingertip ECG-based authentication system using time, frequency domain features and support vector machine.

    Science.gov (United States)

    Singh, Karan; Singhvi, Akshit; Pathangay, Vinod

    2015-08-01

    Acquiring fingertip ECG (electrocardiogram) signal using dry contact electrodes is challenging due to the presence of noise and interference by EMG (electromyogram) potentials. In this paper, we propose a method for using the fingertip ECG signal for biometric authentication. The noisy segments of the signal are segmented out using a variance-based heuristic and the clean signal is used for subsequent processing. By applying baseline correction and band pass filtering, the filtered signal is used for beat feature extraction. The features are used to train a support vector machine (SVM) classifier. Experimental results are presented to show the optimum filter parameters and feature sets for best classification performance. The performance of the proposed method with the optimum parameters was evaluated on a public domain CYBHi dataset with 126 subjects and the beat level EER of 3.4% was obtained. PMID:26736315

  10. Fabrication of four-point biped robot foot module based on contact-resistance force sensor and its evaluation

    International Nuclear Information System (INIS)

    This paper presents the design of robot foot module of four-point biped walking robot and its fabrication. The foot module has four sensor units based on contact-resistance force sensor. The thin-film-type force sensor is fabricated by coating resistive ink on thin polyimide film using silk screening technique. The simple structure is devised and fabricated to assemble the thin force sensor rigidly. The unit force sensor module is evaluated by the calibration setup to obtain the characteristics of repeatability and hysteresis. The sensor module presents hysteresis error of about 5% and repeatability error of about 0.37%. The calculated zero moment point (ZMP) of the foot module is also compared with the measured position using static load of 50 N. The maximum location error of ZMP is less than 10%. The robot foot module shows the possibility of applying it to humanoid walking

  11. COMMUNITY DETECTION USING INTER CONTACT TIME AND SOCIAL CHARACTERISTICS BASED SINGLE COPY ROUTING IN DELAY TOLERANT NETWORKS

    Directory of Open Access Journals (Sweden)

    Nikhil Gondaliya

    2016-02-01

    Full Text Available Delay Tolerant Networks (DTNs where the node connectivity is opportunistic and end-to-end path between any pair of source and destination is not guaranteed most of the time. Hence the messages are transferred from source to destination via intermediate nodes on hop to hop basis using store-carry-forward paradigm. Due to quick advancement in hand held devices such as smart phone and laptop with support of wireless communication interface carried by human being, it is possible in coming days to use DTNs for message dissemination without setting up infrastructure. The routing task becomes challenging in DTNs due to intermittent network connectivity and the connection opportunity arises only when node comes in transmission range of each other. The performance of the routing protocols depend on the selection of appropriate relay node which can deliver the message to final destination in case of source and destination do not meet at all. Many social characteristics are exhibited by the human being like friendship, community, similarity and centrality which can be exploited by the routing protocol in order to take the forwarding decisions. Literature shows that by using these characteristics, the performance of DTN routing protocols have been improved in terms of delivery probability. The existing routing schemes used community detection using aggregated contact duration and contact frequency which does not change over the time period. We propose community detection through Inter Contact Time (ICT between node pair using power law distribution where the members of community are added and removed dynamically. We also considered single copy of each message in entire network to reduce the network overhead. The proposed routing protocol named Social Based Single Copy Routing (SBSCR selects the suitable relay node from the community members only based on the social metrics such as similarity and friendship together. ICTs show power law nature in human

  12. Modeling of contact theories for the manipulation of biological micro/nanoparticles in the form of circular crowned rollers based on the atomic force microscope

    International Nuclear Information System (INIS)

    This article has dealt with the development and modeling of various contact theories for biological nanoparticles shaped as cylinders and circular crowned rollers for application in the manipulation of different biological micro/nanoparticles based on Atomic Force Microscope. First, the effective contact forces were simulated, and their impact on contact mechanics simulation was investigated. In the next step, the Hertz contact model was simulated and compared for gold and DNA nanoparticles with the three types of spherical, cylindrical, and circular crowned roller type contact geometries. Then by reducing the length of the cylindrical section in the circular crowned roller geometry, the geometry of the body was made to approach that of a sphere, and the results were compared for DNA nanoparticles. To anticipatory validate the developed theories, the results of the cylindrical and the circular crowned roller contacts were compared with the results of the existing spherical contact simulations. Following the development of these contact models for the manipulation of various biological micro/nanoparticles, the cylindrical and the circular crowned roller type contact theories were modeled based on the theories of Lundberg, Dowson, Nikpur, Heoprich, and Hertz for the manipulation of biological micro/nanoparticles. Then, for a more accurate validation, the results obtained from the simulations were compared with those obtained by the finite element method and with the experimental results available in previous articles. The previous research works on the simulation of nanomanipulation have mainly investigated the contact theories used in the manipulation of spherical micro/nanoparticles. However since in real biomanipulation situations, biological micro/nanoparticles of more complex shapes need to be displaced in biological environments, this article therefore has modeled and compared, for the first time, different contact theories for use in the biomanipulation of

  13. Energy Efficient Military Mobile Base Station Placement

    Directory of Open Access Journals (Sweden)

    Saikat Ray

    2010-11-01

    Full Text Available This research deals with an energy efficient network for military mobile base station placement. Theproposed method is based on minimizing the energy loss of military communication networks where thebase station is moving along a preset path and the users are constantly moving in an independent speedand direction. It takes into account the free space loss and the knife edge effect for the energy loss toestablish a path weight for the shortest path model. Then, it evaluates the neighboring points to the basestation for the energy loss of the network in order to find the position at which the minimum energy lossoccurs. The results show a clear energy saving advantage when compared to Lloyd-Max’s method

  14. Energy based prediction models for building acoustics

    DEFF Research Database (Denmark)

    Brunskog, Jonas

    2012-01-01

    In order to reach robust and simplified yet accurate prediction models, energy based principle are commonly used in many fields of acoustics, especially in building acoustics. This includes simple energy flow models, the framework of statistical energy analysis (SEA) as well as more elaborated...... principles as, e.g., wave intensity analysis (WIA). The European standards for building acoustic predictions, the EN 12354 series, are based on energy flow and SEA principles. In the present paper, different energy based prediction models are discussed and critically reviewed. Special attention is placed...... on underlying basic assumptions, such as diffuse fields, high modal overlap, resonant field being dominant, etc., and the consequences of these in terms of limitations in the theory and in the practical use of the models....

  15. A Vision-Based Approach for Estimating Contact Forces: Applications to Robot-Assisted Surgery

    Directory of Open Access Journals (Sweden)

    C. W. Kennedy

    2005-01-01

    Full Text Available The primary goal of this paper is to provide force feedback to the user using vision-based techniques. The approach presented in this paper can be used to provide force feedback to the surgeon for robot-assisted procedures. As proof of concept, we have developed a linear elastic finite element model (FEM of a rubber membrane whereby the nodal displacements of the membrane points are measured using vision. These nodal displacements are the input into our finite element model. In the first experiment, we track the deformation of the membrane in real-time through stereovision and compare it with the actual deformation computed through forward kinematics of the robot arm. On the basis of accurate deformation estimation through vision, we test the physical model of a membrane developed through finite element techniques. The FEM model accurately reflects the interaction forces on the user console when the interaction forces of the robot arm with the membrane are compared with those experienced by the surgeon on the console through the force feedback device. In the second experiment, the PHANToM haptic interface device is used to control the Mitsubishi PA-10 robot arm and interact with the membrane in real-time. Image data obtained through vision of the deformation of the membrane is used as the displacement input for the FEM model to compute the local interaction forces which are then displayed on the user console for providing force feedback and hence closing the loop.

  16. Base Program on Energy Related Research

    Energy Technology Data Exchange (ETDEWEB)

    Western Research Institute

    2008-06-30

    The main objective of the Base Research Program was to conduct both fundamental and applied research that will assist industry in developing, deploying, and commercializing efficient, nonpolluting fossil energy technologies that can compete effectively in meeting the energy requirements of the Nation. In that regard, tasks proposed under the WRI research areas were aligned with DOE objectives of secure and reliable energy; clean power generation; development of hydrogen resources; energy efficiency and development of innovative fuels from low and no-cost sources. The goal of the Base Research Program was to develop innovative technology solutions that will: (1) Increase the production of United States energy resources--coal, natural gas, oil, and renewable energy resources; (2) Enhance the competitiveness of United States energy technologies in international markets and assist in technology transfer; (3) Reduce the nation's dependence on foreign energy supplies and strengthen both the United States and regional economies; and (4) Minimize environmental impacts of energy production and utilization. This report summarizes the accomplishments of the overall Base Program. This document represents a stand-alone Final Report for the entire Program. It should be noted that an interim report describing the Program achievements was prepared in 2003 covering the progress made under various tasks completed during the first five years of this Program.

  17. State Energy Base Proposed in Inner Mongolia

    Institute of Scientific and Technical Information of China (English)

    Wang Wenling

    2008-01-01

    @@ Experts recently suggested China set up a state energy base in Inner Mongolia Autonomous Region to ease its energy thirst. The survey was co-conducted by senior researchers from the National Development and Reform Commission, Development Research Center of the State Council, Chinese Academy of Sciences and the Ministry of Finance.

  18. Light-addressable amperometric electrodes for enzyme sensors based on direct quantum dot-electrode contacts

    Science.gov (United States)

    Riedel, M.; Göbel, G.; Parak, W. J.; Lisdat, F.

    2014-03-01

    Quantum dots allow the generation of charge carriers upon illumination. When these particles are attached to an electrode a photocurrent can be generated. This allows their use as a light-switchable layer on the surface. The QDs can not only exchange electronics with the electrode, but can also interact with donor or acceptor compounds in solution providing access to the construction of signal chains starting from an analytic molecule. The magnitude and the direction of the photocurrent depend on several factors such as electrode polarization, solution pH and composition. These defined dependencies have been evaluated with respect to the combination of QD-electrodes with enzyme reactions for sensorial purpose. CdSe/ZnS-QD-modified electrodes can be used to follow enzymatic reactions in solution based on the oxygen sensitivity. In order to develop a photoelectrochemical biosensor, e.g. glucose oxidase is immobilized on the CdSe/ZnS-electrode. One immobilization strategy applies the layer-by-layer-technique of GOD and a polyelectrolyte. Photocurrent measurements of such a sensor show a clear concentration dependent behavior. The principle of combing QD oxidase. The sensitivity of quantum dot electrodes can be influenced by additional nanoparticles, but also by multiple layers of the QDs. In another direction of research it can be influenced by additional nanoparticles, but also by multiple layers of the QDs. In another direction of research it can be demonstrated that direct electron transfer from excited quantum dots can be achieved with the redox protein cytochrome c. This allows the detection of the protein, but also interaction partners such as a enzymes or superoxide.

  19. Late and very-late first-contact schizophrenia and the risk of dementia--a nationwide register based study

    DEFF Research Database (Denmark)

    Kørner, Alex; Lopez, Ana Garcia; Lauritzen, Lise;

    2009-01-01

    OBJECTIVE: To examine whether late and very-late first-contact schizophrenia carry a risk for later development of dementia. METHODS: By linkage of the psychiatric and the somatic nation-wide registers of all out- and in-patients with hospital contact in Denmark, we identified all patients...... with first ever contact during the period from January 1994 to December 2001 with one of the index main diagnoses: late (age >or=40) and very-late first-contact (age >or=60) schizophrenia. First contact osteoarthritis patients as well as data on the general population were used as controls. The first...... diagnosis of dementia for each individual at discharge or at out-patient contact was established. The probability of getting a dementia diagnosis is estimated using Poisson regression models with dementia as the outcome of interest. RESULTS: Twelve thousand six hundred and sixteen and 7,712 individuals were...

  20. Integrated energy systems based on cascade utilization of energy

    Institute of Scientific and Technical Information of China (English)

    JIN Hongguang; LI Bingyu; FENG Zhibing; GAO Lin; HAN Wei

    2007-01-01

    Focusing on the traditional principle of physical energy utilization,new integration concepts for combined cooling,heating and power (CCHP) system were identified,and corresponding systems were investigated.Furthermore,the principle of cascade utilization of both chemical and physical energy in energy systems with the integration of chemical processes and thermal cycles was introduced,along with a general equation describing the interrelationship among energy levels of substance,Gibbs free energy of chemical reaction and physical energy.On the basis of this principle,a polygeneration system for power and liquid fuel (methanol)production has been presented and investigated.This system innovatively integrates a fresh gas preparation subsystem without composition adjustment process (NA) and a methanol synthesis subsystem with partial-recycle scheme (PR).Meanwhile,a multi-functional energy system (MES) that consumes coal and natural gas as fuels simultaneously,and co-generates methanol and power,has been presented.In the MES,coal and natural gas are utilized synthetically based on the method of dual-fuel reforming,which integrates methane/steam reforming and coal combustion.Compared with conventional energy systems that do not consider cascade utilization of chemical energy,both of these systems provide superior performance,whose energy saving ratio can be as high as 10%-15%.With special attention paid to chemical energy utilization,the integration features of these two systems have been revealed,and the important role that the principle of cascade utilization of both chemical and physical energy plays in system integration has been identified.

  1. Non-contact inspection for inner surface of small-diameter pipes based on laser-PSD

    Institute of Scientific and Technical Information of China (English)

    WU En-qi; KE Ying-lin; LI Jiang-xiong

    2005-01-01

    A new non-contact inspection technique based on laser-PSD (position sensitive detector) to inspect the inner surface of small-diameter pipe is proposed,and the corresponding sensor has been developed.After being reflected by two mirrors in series,a laser beam is projected onto the inner wall of a pipe as a small light spot and is read by a two-dimensional PSD.Based on the signals from the PSD and the structure parameters of the sensor,the spot position on the wall can be calculated in a local 3D coordinate system.The spot controlled by the micro-motor driven mirrors will scan a closed section ring on the inner wall of the pipe to obtain the relative coordinates of all the sampled points.The data will be then processed through data segmentation and least square fitting,to reconstruct the section curve used for obtaining the radius and the defect description of the section.Driven by a micro-pipe robot,the sensor can inspect a long curved pipe and obtain its 3-D reconstruction.An inspection system based on this technique can detect the mini-diameter pipe with an inner diameter of 9.5 mm~10.5 mm and a curvature radius larger than 100 mm at a measurement accuracy of the inner surface defect of ±0.1 mm.

  2. Using a consensus approach based on the conservation of inter-residue contacts to rank CAPRI models

    KAUST Repository

    Vangone, Anna

    2013-10-17

    Herein we propose the use of a consensus approach, CONSRANK, for ranking CAPRI models. CONSRANK relies on the conservation of inter-residue contacts in the analyzed decoys ensemble. Models are ranked according to their ability to match the most frequently observed contacts. We applied CONSRANK to 19 CAPRI protein-protein targets, covering a wide range of prediction difficulty and involved in a variety of biological functions. CONSRANK results are consistently good, both in terms of native-like (NL) solutions ranked in the top positions and of values of the Area Under the receiver operating characteristic Curve (AUC). For targets having a percentage of NL solutions above 3%, an excellent performance is found, with AUC values approaching 1. For the difficult target T46, having only 3.4% NL solutions, the number of NL solutions in the top 5 and 10 ranked positions is enriched by a factor 30, and the AUC value is as high as 0.997. AUC values below 0.8 are only found for targets featuring a percentage of NL solutions within 1.1%. Remarkably, a false consensus emerges only in one case, T42, which happens to be an artificial protein, whose assembly details remain uncertain, based on controversial experimental data. We also show that CONSRANK still performs very well on a limited number of models, provided that more than 1 NL solution is included in the ensemble, thus extending its applicability to cases where few dozens of models are available.© 2013 Wiley Periodicals, Inc.

  3. MEMS based pyroelectric thermal energy harvester

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, Scott R; Datskos, Panagiotis G

    2013-08-27

    A pyroelectric thermal energy harvesting apparatus for generating an electric current includes a cantilevered layered pyroelectric capacitor extending between a first surface and a second surface, where the first surface includes a temperature difference from the second surface. The layered pyroelectric capacitor includes a conductive, bimetal top electrode layer, an intermediate pyroelectric dielectric layer and a conductive bottom electrode layer. In addition, a pair of proof masses is affixed at a distal end of the layered pyroelectric capacitor to face the first surface and the second surface, wherein the proof masses oscillate between the first surface and the second surface such that a pyroelectric current is generated in the pyroelectric capacitor due to temperature cycling when the proof masses alternately contact the first surface and the second surface.

  4. First-principles investigation on the electronic efficiency and binding energy of the contacts formed by graphene and poly-aromatic hydrocarbon anchoring groups

    KAUST Repository

    Li, Yang

    2015-04-28

    © 2015 AIP Publishing LLC. The electronic efficiency and binding energy of contacts formed between graphene electrodes and poly-aromatic hydrocarbon (PAH) anchoring groups have been investigated by the non-equilibrium Green\\'s function formalism combined with density functional theory. Our calculations show that PAH molecules always bind in the interior and at the edge of graphene in the AB stacking manner, and that the binding energy increases following the increase of the number of carbon and hydrogen atoms constituting the PAH molecule. When we move to analyzing the electronic transport properties of molecular junctions with a six-carbon alkyne chain as the central molecule, the electronic efficiency of the graphene-PAH contacts is found to depend on the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the corresponding PAH anchoring group, rather than its size. To be specific, the smaller is the HOMO-LUMO gap of the PAH anchoring group, the higher is the electronic efficiency of the graphene-PAH contact. Although the HOMO-LUMO gap of a PAH molecule depends on its specific configuration, PAH molecules with similar atomic structures show a decreasing trend for their HOMO-LUMO gap as the number of fused benzene rings increases. Therefore, graphene-conjugated molecule-graphene junctions with high-binding and high-conducting graphene-PAH contacts can be realized by choosing appropriate PAH anchor groups with a large area and a small HOMO-LUMO gap.

  5. CVLEACH: Coverage based energy efficient LEACH algorithm

    Directory of Open Access Journals (Sweden)

    Ankit Thakkar

    2012-06-01

    Full Text Available Designing a protocol stack for wireless sensor network (WSNis a challenging task due to energy, computational and storageconstraints. Energy spent for communication between sensornodes dominates the energy spent for the computation [10].Multi-hop short range communication between wireless sensorsnodes is energy efficient compared to single-hop long rangecommunication. Hierarchical clustering is one of the possiblesolutions to save energy of wireless sensor nodes. Low-EnergyAdaptive Clustering Hierarchy (LEACH, Centralized Low-Energy Adaptive Clustering Hierarchy (LEACH-C andAdvanced Low-Energy Adaptive Clustering Hierarchy(ALEACH are energy efficient hierarchical clustering routingprotocol. In this paper we proposed Coverage based Low-EnergyAdaptive Clustering Hierarchy routing protocol – CVLEACH tomake uniform distribution of Cluster Heads (CHs by creatingnon-overlapped cluster regions using overhearing properties ofthe sensor nodes, which makes the routing protocol more energyefficient and prolongs life time of a wireless sensor network.Simulation results show that CVLEACH improves network lifetime compared to LEACH and ALEACH algorithms.

  6. Estimation of the age-specific per-contact probability of Ebola virus transmission in Liberia using agent-based simulations

    Science.gov (United States)

    Siettos, Constantinos I.; Anastassopoulou, Cleo; Russo, Lucia; Grigoras, Christos; Mylonakis, Eleftherios

    2016-06-01

    Based on multiscale agent-based computations we estimated the per-contact probability of transmission by age of the Ebola virus disease (EVD) that swept through Liberia from May 2014 to March 2015. For the approximation of the epidemic dynamics we have developed a detailed agent-based model with small-world interactions between individuals categorized by age. For the estimation of the structure of the evolving contact network as well as the per-contact transmission probabilities by age group we exploited the so called Equation-Free framework. Model parameters were fitted to official case counts reported by the World Health Organization (WHO) as well as to recently published data of key epidemiological variables, such as the mean time to death, recovery and the case fatality rate.

  7. Thermal fluctuations of an interface near a contact line

    CERN Document Server

    Belardinelli, D; Gross, M; Andreotti, B

    2016-01-01

    The effect of thermal fluctuations near a contact line of a liquid interface partially wetting an impenetrable substrate is studied analytically and numerically. Promoting both the interface profile and the contact line position to random variables, we explore the equilibrium properties of the corresponding fluctuating contact line problem based on an interfacial Hamiltonian involving a "contact" binding potential. To facilitate an analytical treatment we consider the case of a one-dimensional interface. The effective boundary condition at the contact line is determined by a dimensionless parameter that encodes the relative importance of thermal energy and substrate energy at the microscopic scale. We find that this parameter controls the transition from a partially wetting to a pseudo-partial wetting state, the latter being characterized by a thin prewetting film of fixed thickness. In the partial wetting regime, instead, the profile typically approaches the substrate via an exponentially thinning prewetting...

  8. Non-thermal alloyed ohmic contact process of GaN-based HEMTs by pulsed laser annealing

    International Nuclear Information System (INIS)

    We have demonstrated Si implantation incorporation into GaN HEMTs with a non-alloyed ohmic contact process. We optimized the power density of pulsed laser annealing to activate implanted Si dopants without a thermal metallization process. The experimental results show that the GaN surface will be reformed under the high power density of the illumination conditions. It provides a smooth surface for following contact engineering and leads to comparable contact resistance. The transmission line model (TLM) measurement shows a lower contact resistance to 6.8 × 10−7 Ω · cm2 via non-alloyed contact technology with significantly improved surface morphology of the contact metals. DC measurement of HEMTs shows better current and on-resistance. The on-resistance could be decreased from 2.18 to 1.74 mΩ-cm2 as we produce a lower contact resistance. Pulsed laser annealing also results in lower gate leakage and smaller dispersion under a pulse I-V measurement, which implies that the density of the surface state is improved. (paper)

  9. CFD based approach for modeling direct contact condensation heat transfer in two-phase turbulent stratified flows

    International Nuclear Information System (INIS)

    This paper describes a CFD based strategy for the modeling of stratified two-phase flows with heat and mass transfer across a moving steam-water interface due to direct contact condensation. Such flows have been of major importance for example in connection with the analysis of nuclear reactor safety systems, in particular during two-phase Pressurized Thermal Shock (PTS) scenarios. The approach is based on the two-fluid phase-average model. The interfacial friction was modeled by using an Algebraic Interfacial Area Density (AIAD) framework where the drag coefficient is a function of the local flow characteristics. To show the impact of the modeling of interfacial friction the simulation with the AIAD model was compared with a simulation where a constant drag coefficient of 0.44 was used in the whole domain. For the modeling of interfacial heat and mass transfer two correlations for the water heat transfer coefficient based on the penetration theory were utilized. The CFD simulations were validated against a steady-state TOPFLOW-PTS steam/water experiment. In the experiment, very detailed temperature measurements were conducted using special thermocouple lances and infrared thermography. Total condensation rate was determined indirectly by using three different methods. The simulations have shown that the results obtained with the AIAD model are considerably closer to the experimental observations than the results obtained with the constant drag coefficient. The condensation models used in the current study predict quite different total condensation rates. That caused significant differences in the temperature field. The simulations of the TOPFLOW-PTS steam/water experiment with condensation have shown that the proposed CFD modeling approach can be successfully applied for the prediction of temperature field and condensation rate during two-phase Pressurized Thermal Shock scenarios. However, the modeling of turbulent interfacial heat transfer should be improved

  10. Tariff based value of wind energy

    International Nuclear Information System (INIS)

    In this article an approach for determining a value of wind energy is presented. Calculation is based on wholesale tariffs, i.e. the value of wind energy is defined in comparison with other purchase. This approach can be utilised as an aid in the investment planning in defining the benefits of new wind generation capacity. Linear programming optimization method is used. A case study is presented for different wind scenarios. The value of wind energy can vary remarkably depending on timing of power output. (author)

  11. Tariff based value of wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Raekkoelaeinen, J.; Vilkko, M.; Antila, H.; Lautala, P. [Tampere Univ. of Technology (Finland)

    1995-12-31

    In this article an approach for determining a value of wind energy is presented. Calculation is based on wholesale tariffs, i.e. the value of wind energy is defined in comparison with other purchase. This approach can be utilised as an aid in the investment planning in defining the benefits of new wind generation capacity. Linear programming optimization method is used. A case study is presented for different wind scenarios. The value of wind energy can vary remarkably depending on timing of power output. (author)

  12. Thermal energy harvesting plasmonic based chemical sensors.

    Science.gov (United States)

    Karker, Nicholas; Dharmalingam, Gnanaprakash; Carpenter, Michael A

    2014-10-28

    Detection of gases such as H2, CO, and NO2 at 500 °C or greater requires materials with thermal stability and reliability. One of the major barriers toward integration of plasmonic-based chemical sensors is the requirement of multiple components such as light sources and spectrometers. In this work, plasmonic sensing results are presented where thermal energy is harvested using lithographically patterned Au nanorods, replacing the need for an external incident light source. Gas sensing results using the harvested thermal energy are in good agreement with sensing experiments, which used an external incident light source. Principal Component Analysis (PCA) was used to reduce the wavelength parameter space from 665 variables down to 4 variables with similar levels of demonstrated selectivity. The combination of a plasmonic-based energy harvesting sensing paradigm with PCA analysis offers a novel path toward simplification and integration of plasmonic-based sensing methods. PMID:25280004

  13. Effect of gamma irradiation on Schottky-contacted vertically aligned ZnO nanorod-based hydrogen sensor

    Science.gov (United States)

    Ranwa, Sapana; Singh Barala, Surendra; Fanetti, Mattia; Kumar, Mahesh

    2016-08-01

    We report the impact of gamma irradiation on the performance of a gold Schottky-contacted ZnO nanorod-based hydrogen sensor. RF-sputtered vertically aligned highly c-axis-oriented ZnO NRs were grown on Si(100) substrate. X-ray diffraction shows no significant change in crystal structure at low gamma doses from 1 to 5 kGy. As gamma irradiation doses increase to 10 kGy, the single crystalline ZnO structure converts to polycrystalline. The photoluminescence spectra also shows suppression of the near-band emission peak and the huge wide-band spectrum indicates the generation of structural defects at high gamma doses. At 1 kGy, the hydrogen sensor response was enhanced from 67% to 77% for 1% hydrogen in pure argon at a 150 °C operating temperature. However, at 10 kGy, the relative response decreases to 33.5%. High gamma irradiation causes displacement damage and defects in ZnO NRs, and as a result, degrades the sensor’s performance as a result. Low gamma irradiation doses activate the ZnO NR surface through ionization, which enhances the sensor performance. The relative response of the hydrogen sensor was enhanced by ∼14.9% with respect to pristine ZnO using 1 kGy gamma ray treatment.

  14. Non-contact online thickness measurement system for metal films based on eddy current sensing with distance tracking technique

    Science.gov (United States)

    Li, Wei; Wang, Hongbo; Feng, Zhihua

    2016-04-01

    This paper proposes an online, non-contact metal film thickness measurement system based on eddy current sensing. The slope of the lift-off curve (LOC) is used for characterizing target thickness. Theoretical derivation was conducted to prove that the slope is independent of the lift-off variation. In practice, the measurement has some immunity to the lift-off, but not perfect. The slope of LOC is still affected at some extent by the lift-off. Hence, a height tracking system was also proposed, which could stabilize the distance between the sensor and the target and significantly reduce the lift-off effect. The height tracking system contains a specially designed probe, which could vibrate rapidly to obtain a fast measurement speed, and its height can be adjusted up and down continuously to stabilize the lift-off. The sensor coil in the thickness measurement system was also used as the height sensor in the height tracking system. Several experiments were conducted to test the system performances under static and dynamic conditions. This measurement system demonstrated significant advantages, such as simple and clear conversion between the slope of LOC and target thickness, high resolution and stability, and minimized effect of lift-off variation.

  15. Study of non-contact measurement of the thermal expansion coefficients of materials based on laser feedback interferometry.

    Science.gov (United States)

    Zheng, Fasong; Tan, Yidong; Lin, Jing; Ding, Yingchun; Zhang, Shulian

    2015-04-01

    The noncooperative and ultrahigh sensitive length measurement approach is of great significance to the study of a high-precision thermal expansion coefficient (TEC) determination of materials at a wide temperature range. The novel approach is presented in this paper based on the Nd:YAG microchip laser feedback interferometry with 1064 nm wavelength, the beam frequency of which is shifted by a pair of acousto-optic modulators and then the heterodyne phase measurement technique is used. The sample is placed in a muffle furnace with two coaxial holes opened on the opposite furnace walls. The measurement beams are perpendicular and coaxial on each surface of the sample, the configuration which can not only achieve the length measurement of sample but also eliminate the influence of the distortion of the sample supporter. The reference beams inject on the reference mirrors which are put as possible as near the holes, respectively, to eliminate the air disturbances and the influence of thermal lens effect out of the furnace chamber. For validation, the thermal expansion coefficients of aluminum and steel 45 samples are measured from room temperature to 748 K, which proved measurement repeatability of TECs is better than 0.6 × 10(-6)(K(-1)) at the range of 298 K-598 K and the high-sensitive non-contact measurement of the low reflectivity surface induced by the oxidization of the samples at the range of 598 K-748 K. PMID:25933843

  16. Adhesive Wear and Frictional Behavior of Multilayered Polyester Composite Based on Betelnut Fiber Mats Under Wet Contact Conditions

    Science.gov (United States)

    Yousif, B. F.; Devadas, Alvin; Yusaf, Talal F.

    In the current study, a multilayered polyester composite based on betelnut fiber mats is fabricated. The adhesive wear and frictional performance of the composite was studied against a smooth stainless steel at different sliding distances (0-6.72 km) and applied loads (20-200 N) at 2.8 m/s sliding velocity. Variations in specific wear rate and friction coefficient were evaluated at two different orientations of fiber mat; namely parallel (P-O) and normal (N-O). Results obtained were presented against sliding distance. The worn surfaces of the composite were studied using an optical microscope. The effect of the composite sliding on the stainless steel counterface roughness was investigated. The results revealed that the wear performance of betelnut fiber reinforced polyester (BFRP) composite under wet contact condition was highly dependent on test parameters and fiber mat orientation. The specific wear rate performance for each orientation showed an inverse relationship to sliding distance. BFRP composite in N-O exhibited better wear performance compared with P-O. However, the friction coefficient in N-O was higher than that in P-O at lower range of applied load. The predominant wear mechanism was debonding of fiber with no pullout or ploughing. Moreover, at higher applied loads, micro- and macrocracking and fracture were observed in the resinous region.

  17. Influence of a triazine derivative-based biocide on microbial biofilms of cutting fluids in contact with different substrates.

    Science.gov (United States)

    Lucchesi, Eliane G; Eguchi, Sílvia Y; Moraes, Angela M

    2012-05-01

    Although biofilms are often associated with hospital infection problems owing to their high resistance to antimicrobial agents, in recent years biofilms have also been studied in the industrial sector, mainly because they are a major cause of contamination outbreaks in facilities and products. The aim of this study was to investigate whether different materials commonly found in the metalworking industries have different biofilm formation characteristics when in contact with contaminated cutting fluid as well as to establish an optimal concentration of a triazine-based antimicrobial agent to protect the oil/water emulsion and also to delay or interrupt the development of biofilms. Biofilms grown on the surface of carbon steel, stainless steel, aluminum, polyvinyl chloride, and glass were analyzed in terms of cell growth and susceptibility to the tested biocide. The results showed that the type of material used had little influence on cell adhesion or on the microbicide concentration required to control and eradicate microorganisms suspended in the emulsion and in the biofilms. PMID:22270891

  18. Non-contact online thickness measurement system for metal films based on eddy current sensing with distance tracking technique.

    Science.gov (United States)

    Li, Wei; Wang, Hongbo; Feng, Zhihua

    2016-04-01

    This paper proposes an online, non-contact metal film thickness measurement system based on eddy current sensing. The slope of the lift-off curve (LOC) is used for characterizing target thickness. Theoretical derivation was conducted to prove that the slope is independent of the lift-off variation. In practice, the measurement has some immunity to the lift-off, but not perfect. The slope of LOC is still affected at some extent by the lift-off. Hence, a height tracking system was also proposed, which could stabilize the distance between the sensor and the target and significantly reduce the lift-off effect. The height tracking system contains a specially designed probe, which could vibrate rapidly to obtain a fast measurement speed, and its height can be adjusted up and down continuously to stabilize the lift-off. The sensor coil in the thickness measurement system was also used as the height sensor in the height tracking system. Several experiments were conducted to test the system performances under static and dynamic conditions. This measurement system demonstrated significant advantages, such as simple and clear conversion between the slope of LOC and target thickness, high resolution and stability, and minimized effect of lift-off variation.

  19. Skin thermal response to sapphire contact and cryogen spray cooling: a comparative study based on measurements in a skin phantom

    Science.gov (United States)

    Torres, Jorge H.; Nelson, J. Stuart; Tanenbaum, B. S.; Anvari, Bahman

    2000-05-01

    Non-specific thermal injury to the epidermis may occur as a result of laser treatment of cutaneous hypervascular malformations (e.g. port wine stains) and other dermatoses. Methods to protect the epidermis from thermal injury include sapphire contact cooling (SCC) and cryogen spray cooling (CSC). Evaluation of the skin thermal response to either cooling method and better understanding of the heat transfer process at the skin surface are essential for further optimization of cooling technique during laser therapy. We present internal temperature measurements in an epoxy resin phantom in response to both SCC and CSC, and use the results in conjunction with a mathematical model to predict the temperature distributions within human skin. Based on our results, a conductive heat transfer process at the skin interface appears to be the primary mechanism for both SCC and CSC. In the case of CSC, 'film cooling' rather than 'evaporative cooling' seems to be the dominant mode during the spurt duration. Currently, due to the lower temperature of the cryogen film and its shorter time of application, CSC produces larger temperature reductions at the skin surface and smaller temperature reductions at depths greater than 200 micrometer (i.e., higher spatial selectivity) when compared to SCC. However, SCC can potentially induce temperature reductions comparable to those produced by CSC if a sapphire temperature similar to that for a cryogen could be achieved in practice.

  20. Optimal contact definition for reconstruction of Contact Maps

    Directory of Open Access Journals (Sweden)

    Stehr Henning

    2010-05-01

    Full Text Available Abstract Background Contact maps have been extensively used as a simplified representation of protein structures. They capture most important features of a protein's fold, being preferred by a number of researchers for the description and study of protein structures. Inspired by the model's simplicity many groups have dedicated a considerable amount of effort towards contact prediction as a proxy for protein structure prediction. However a contact map's biological interest is subject to the availability of reliable methods for the 3-dimensional reconstruction of the structure. Results We use an implementation of the well-known distance geometry protocol to build realistic protein 3-dimensional models from contact maps, performing an extensive exploration of many of the parameters involved in the reconstruction process. We try to address the questions: a to what accuracy does a contact map represent its corresponding 3D structure, b what is the best contact map representation with regard to reconstructability and c what is the effect of partial or inaccurate contact information on the 3D structure recovery. Our results suggest that contact maps derived from the application of a distance cutoff of 9 to 11Å around the Cβ atoms constitute the most accurate representation of the 3D structure. The reconstruction process does not provide a single solution to the problem but rather an ensemble of conformations that are within 2Å RMSD of the crystal structure and with lower values for the pairwise average ensemble RMSD. Interestingly it is still possible to recover a structure with partial contact information, although wrong contacts can lead to dramatic loss in reconstruction fidelity. Conclusions Thus contact maps represent a valid approximation to the structures with an accuracy comparable to that of experimental methods. The optimal contact definitions constitute key guidelines for methods based on contact maps such as structure prediction through

  1. Hydrogen based energy storage for solar energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Vanhanen, J.P.; Hagstroem, M.T.; Lund, P.H. [Helsinki Univ. of Technology, Otaniemi (Finland). Dept. of Engineering Physics and Mathematics; Leppaenen, J.R.; Nieminen, J.P. [Neste Oy (Finland)

    1998-12-31

    Hydrogen based energy storage options for solar energy systems was studied in order to improve their overall performance. A 1 kW photovoltaic hydrogen (PV-H2) pilot-plant and commercial prototype were constructed and a numerical simulation program H2PHOTO for system design and optimisation was developed. Furthermore, a comprehensive understanding of conversion (electrolysers and fuel cells) and storage (metal hydrides) technologies was acquired by the project partners. The PV-H{sub 2} power system provides a self-sufficient solution for applications in remote locations far from electric grids and maintenance services. (orig.)

  2. High temperature tribological behaviour of carbon based (B{sub 4}C and DLC) coatings in sliding contact with aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Gharam, A. Abou, E-mail: abougha@uwindsor.c [Mechanical Automotive and Materials Engineering Department, University of Windsor, Windsor, ON, N9B3P4 (Canada); Lukitsch, M.J.; Balogh, M.P. [Chemical Sciences and Materials Systems Laboratory, General Motors R and D Center, 30500 Mound Road, Warren, MI 48090-9055 (United States); Alpas, A.T. [Mechanical Automotive and Materials Engineering Department, University of Windsor, Windsor, ON, N9B3P4 (Canada)

    2010-12-30

    Carbon based coatings, particularly diamond-like carbon (DLC) films are known to resist aluminum adhesion and reduce friction at room temperature. This attractive tribological behaviour is useful for applications such as tool coatings used for aluminum forming and machining. However, for those operations that are performed at elevated temperatures (e.g. hot forming) or that generate frictional heat during contact (e.g. dry machining) the suitable coatings are required to maintain their tribological properties at high temperatures. Candidates for these demanding applications include boron carbide (B{sub 4}C) and DLC coatings. An understanding of the mechanisms of friction, wear and adhesion of carbon based coatings against aluminum alloys at high temperatures will help in designing coatings with improved high temperature tribological properties. With this goal in mind, this study focused on B{sub 4}C and a hydrogenated DLC coatings sliding against a 319 grade cast aluminum alloy by performing pin-on-disk experiments at temperatures up to 400 {sup o}C. Experimental results have shown that the 319 Al/B{sub 4}C tribosystem generated coefficient of friction (COF) values ranging between 0.42 and 0.65, in this temperature range. However, increased amounts of aluminum adhesion were detected in the B{sub 4}C wear tracks at elevated temperatures. Focused ion beam (FIB) milled cross sections of the wear tracks revealed that the coating failed due to shearing along the columnar grain boundaries of the coating. The 319 Al/DLC tribosystem maintained a low COF (0.15-0.06) from room temperature up to 200 {sup o}C. This was followed by an abrupt increase to 0.6 at 400 {sup o}C. The deterioration of friction behaviour at T > 200 {sup o}C was attributed to the exhaustion of hydrogen and hydroxyl passivants on the carbon transfer layer formed on the Al pin.

  3. High temperature tribological behaviour of carbon based (B4C and DLC) coatings in sliding contact with aluminum

    International Nuclear Information System (INIS)

    Carbon based coatings, particularly diamond-like carbon (DLC) films are known to resist aluminum adhesion and reduce friction at room temperature. This attractive tribological behaviour is useful for applications such as tool coatings used for aluminum forming and machining. However, for those operations that are performed at elevated temperatures (e.g. hot forming) or that generate frictional heat during contact (e.g. dry machining) the suitable coatings are required to maintain their tribological properties at high temperatures. Candidates for these demanding applications include boron carbide (B4C) and DLC coatings. An understanding of the mechanisms of friction, wear and adhesion of carbon based coatings against aluminum alloys at high temperatures will help in designing coatings with improved high temperature tribological properties. With this goal in mind, this study focused on B4C and a hydrogenated DLC coatings sliding against a 319 grade cast aluminum alloy by performing pin-on-disk experiments at temperatures up to 400 oC. Experimental results have shown that the 319 Al/B4C tribosystem generated coefficient of friction (COF) values ranging between 0.42 and 0.65, in this temperature range. However, increased amounts of aluminum adhesion were detected in the B4C wear tracks at elevated temperatures. Focused ion beam (FIB) milled cross sections of the wear tracks revealed that the coating failed due to shearing along the columnar grain boundaries of the coating. The 319 Al/DLC tribosystem maintained a low COF (0.15-0.06) from room temperature up to 200 oC. This was followed by an abrupt increase to 0.6 at 400 oC. The deterioration of friction behaviour at T > 200 oC was attributed to the exhaustion of hydrogen and hydroxyl passivants on the carbon transfer layer formed on the Al pin.

  4. Contact position sensor using constant contact force control system

    Science.gov (United States)

    Sturdevant, Jay (Inventor)

    1995-01-01

    A force control system (50) and method are provided for controlling a position contact sensor (10) so as to produce a constant controlled contact force therewith. The system (50) includes a contact position sensor (10) which has a contact probe (12) for contacting the surface of a target to be measured and an output signal (V.sub.o) for providing a position indication thereof. An actuator (30) is provided for controllably driving the contact position sensor (10) in response to an actuation control signal (I). A controller (52) receives the position indication signal (V.sub.o) and generates in response thereto the actuation control signal (I) so as to provide a substantially constant selective force (F) exerted by the contact probe (12). The actuation drive signal (I) is generated further in response to substantially linear approximation curves based on predetermined force and position data attained from the sensor (10) and the actuator (30).

  5. Energy-Based Analysis of Ultrasonically Assisted Turning

    Directory of Open Access Journals (Sweden)

    G.A. Volkov

    2011-01-01

    Full Text Available The process of ultrasonically-assisted turning (UAT is a superposition of vibration of a cutting tool on its standard movement in conventional turning (CT. The former technique has several advantages compared with the latter, one of the main being a significant decrease in the level of cutting forces. In this paper the effects observed in UAT are analysed employing ideas of dynamic fracture mechanics. The active stage of loading duration depends heavily on ultrasonic frequency and the cutting speed; he application of the fracture criterion based on the notion of incubation time makes it possible to calculate a dependence of this duration on its threshold amplitude. An estimation of energy, necessary to create a threshold pulse in the material, is made by solving the contact Hertz problem. The obtained time dependence of energy has a marked minimum. Thus, the existence of energy-efficient loading duration is demonstrated. This explains the decrease in the cutting force resulting from superimposed ultrasonic vibration. The obtained results are in agreement with experiments on ultrasonic assisted machining of aluminium and Inconel 718 alloy.

  6. Pervasive Computing Based Intelligent Energy Conservation System

    OpenAIRE

    Dr. A.Kanagaraj; Ms S.Sharmila

    2015-01-01

    Most of the HVAC system in home is running based on static control algorithm; based on fixed work schedules. In that old system energy became waste when home contains low or no people occupancy. In this paper we presented new dynamic approach of HVAC system control, by combined with pervasive computing. Pervasive computing can be defined as availability of centralized system and information anywhere and anytime. We achieved our target by using occupancy sensors for collecting home status. ...

  7. Topological insulator-based energy efficient devices

    Science.gov (United States)

    Chen, Yong P.

    2012-06-01

    Topological insulators (TI) have emerged as a new class of quantum materials with many novel and unusual properties. In this article, we will give a brief review of the key electronic properties of topological insulators, including the signatures for the unusual electronic transport properties of their characteristic topological surface states (TSS). We will then discuss how these novel properties and physics may be utilized for TI-based energy efficient devices, such as lowpower- consumption electronics and high performance thermo-electrics. Furthermore, going beyond conventional singleparticle, charge-based transport, to utilize coherent many-body coherent ground states such as excitonic condensates (EC), new and intriguing functionalities previously unexplored in electronic and energy devices may be realized with the potential to dramatically improve the energy efficiency.

  8. Electromagnetic ferrofluid-based energy harvester

    Energy Technology Data Exchange (ETDEWEB)

    Bibo, A.; Masana, R.; King, A.; Li, G. [Nonlinear Vibrations and Energy Harvesting Laboratory (NOVEHL), Department of Mechanical Engineering, Clemson University, Clemson, SC 29634 (United States); Daqaq, M.F., E-mail: mdaqaq@clemson.edu [Nonlinear Vibrations and Energy Harvesting Laboratory (NOVEHL), Department of Mechanical Engineering, Clemson University, Clemson, SC 29634 (United States)

    2012-06-25

    This Letter investigates the use of ferrofluids for vibratory energy harvesting. In particular, an electromagnetic micro-power generator which utilizes the sloshing of a ferrofluid column in a seismically-excited tank is proposed to transform mechanical motions directly into electricity. Unlike traditional electromagnetic generators that implement a solid magnet, ferrofluids can easily conform to different shapes and respond to very small acceleration levels offering an untapped opportunity to design scalable energy harvesters. The feasibility of the proposed concept is demonstrated and its efficacy is discussed through several experimental studies. -- Highlights: ► A ferrofluid-based electromagnetic energy harvester is proposed and tested. Conformability of fluids offers unique capabilities to design scalable harvesters. ► Power is sensitive to changes in the fluid surface area and external magnetization. ► Device generates 1 microwatt of output power at a base acceleration of 3 m/s{sup 2}.

  9. Sustainable urban regeneration based on energy balance

    NARCIS (Netherlands)

    Van Timmeren, A.; Zwetsloot, J.; Brezet, H.; Silvester, S.

    2012-01-01

    In this paper, results are reported of a technology assessment of the use and integration of decentralized energy systems and storage devices in an urban renewal area. First the general context of a different approach based on 'rethinking' and the incorporation of ongoing integration of coming econo

  10. Who puts the most energy into energy conservation? A segmentation of energy consumers based on energy-related behavioral characteristics

    International Nuclear Information System (INIS)

    The present paper aims to identify and describe different types of energy consumers in a more comprehensive way than previous segmentation studies using cluster analysis. Energy consumers were segmented based on their energy-related behavioral characteristics. In addition to purchase- and curtailment-related energy-saving behavior, consumer classification was also based on acceptance of policy measures and energy-related psychosocial factors, so the used behavioral segmentation base was more comprehensive compared to other studies. Furthermore, differentiation between the energy-saving purchase of daily products, such as food, and of energy efficient appliances allowed a more differentiated characterization of the energy consumer segments. The cluster analysis revealed six energy consumer segments: the idealistic, the selfless inconsequent, the thrifty, the materialistic, the convenience-oriented indifferent, and the problem-aware well-being-oriented energy consumer. Findings emphasize that using a broader and more distinct behavioral base is crucial for an adequate and differentiated description of energy consumer types. The paper concludes by highlighting the most promising energy consumer segments and discussing possible segment-specific marketing and policy strategies. - Highlights: ► By applying a cluster-analytic approach, new energy consumer segments are identified. ► A comprehensive, differentiated description of the different energy consumer types is provided. ► A distinction between purchase of daily products and energy efficient appliances is essential. ► Behavioral variables are a more suitable base for segmentation than general characteristics.

  11. Sustainable Urban Regeneration Based on Energy Balance

    Directory of Open Access Journals (Sweden)

    Sacha Silvester

    2012-07-01

    Full Text Available In this paper, results are reported of a technology assessment of the use and integration of decentralized energy systems and storage devices in an urban renewal area. First the general context of a different approach based on 'rethinking' and the incorporation of ongoing integration of coming economical and environmental interests on infrastructure, in relation to the sustainable urban development and regeneration from the perspective of the tripod people, technology and design is elaborated. However, this is at different scales, starting mainly from the perspective of the urban dynamics. This approach includes a renewed look at the ‘urban metabolism’ and the role of environmental technology, urban ecology and environment behavior focus. Second, the potential benefits of strategic and balanced introduction and use of decentralized devices and electric vehicles (EVs, and attached generation based on renewables are investigated in more detail in the case study of the ‘Merwe-Vierhaven’ area (MW4 in the Rotterdam city port in the Netherlands. In order to optimize the energy balance of this urban renewal area, it is found to be impossible to do this by tuning the energy consumption. It is more effective to change the energy mix and related infrastructures. However, the problem in existing urban areas is that often these areas are restricted to a few energy sources due to lack of available space for integration. Besides this, energy consumption in most cases is relatively concentrated in (existing urban areas. This limits the potential of sustainable urban regeneration based on decentralized systems, because there is no balanced choice regarding the energy mix based on renewables and system optimization. Possible solutions to obtain a balanced energy profile can come from either the choice to not provide all energy locally, or by adding different types of storage devices to the systems. The use of energy balance based on renewables as a

  12. Department of Energy Review of Laboratory Programs for Women Points-of-Contact Committee: Comparative Report, June 1995

    Energy Technology Data Exchange (ETDEWEB)

    McLane, V.; Layne, A.

    1995-06-01

    A survey of the DOE facilities was undertaken by the Points-of-Contact for the DOE Review of Laboratory Programs for Women in order to gather data to be used as a baseline against which to measure future progress. We plan to look at current programs already in place and evaluate them with a view to deciding which programs are most effective, and selecting model programs suitable for implementation at other facilities. The survey focused on four areas: 1) statistical data, 2) laboratory policy, 3) formal and informal programs which affect the quality of life in the work environment, and career development and advancement, and 4) educational programs. Although this report focuses on women, the problems discussed affect all DOE facility employees.

  13. Characterization of interface reaction of Ti/Al-based ohmic contacts on AlGaN/GaN epitaxial layers on GaN substrate

    Science.gov (United States)

    Zadeh, Daryoush H.; Tanabe, Shinichi; Watanabe, Noriyuki; Matsuzaki, Hideaki

    2016-05-01

    The ohmic properties of Ti/Al/Mo/Au contacts on a high-quality AlGaN/GaN heterostructure epitaxially grown on a GaN substrate were investigated. Systematic structural and electrical analyses of the metal/AlGaN interface after annealing in N2 at 700 and 900 °C were conducted. After annealing at 900 °C, a new Al-rich interlayer with nitrogen vacancies was formed at the metal/AlGaN interface. Ohmic contacts with a low specific contact resistance (ρc) of 5.1 × 10‑6 Ω cm2 and a dominant field emission carrier transport mechanism were achieved. The fabrication of recessed-AlGaN-structured ohmic contact with ρc as low as 2.4 × 10‑5 Ω cm2 at a low annealing temperature of 650 °C, was also successfully demonstrated. This result indicates that a process methodology can be provided for fabricating low-resistivity ohmic contacts with a low thermal budget on a high-quality AlGaN/GaN structure, which is based on an appropriate control of the metal/AlGaN interface and AlGaN thickness rather than relying on the existence of threading dislocations.

  14. Pervasive Computing Based Intelligent Energy Conservation System

    Directory of Open Access Journals (Sweden)

    Dr. A.Kanagaraj

    2015-11-01

    Full Text Available Most of the HVAC system in home is running based on static control algorithm; based on fixed work schedules. In that old system energy became waste when home contains low or no people occupancy. In this paper we presented new dynamic approach of HVAC system control, by combined with pervasive computing. Pervasive computing can be defined as availability of centralized system and information anywhere and anytime. We achieved our target by using occupancy sensors for collecting home status. Initially our occupancy sensors collect human presence and current HVAC status details and stored in centralized system. Then based on our user defined threshold value the centralized system maintains the building's heating, cooling and air quality conditions by controlling HVAC devices. I.e. this system turned off HVAC systems when a home is unoccupied, or put the system into an energy saving sleep mode when persons are asleep.

  15. Clean Cities Program Contacts (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-03-01

    This fact sheet provides contact information for program staff of the U.S. Department of Energy's Clean Cities program, as well as contact information for the nearly 100 local Clean Cities coalitions across the country.

  16. Light extraction efficiency enhancement of GaN-based blue LEDs based on ITO/ InxO ohmic contacts with microstructure formed by annealing in oxygen.

    Science.gov (United States)

    Luo, Yi; Bai, Yiming; Han, Yanjun; Li, Hongtao; Wang, Lai; Wang, Jian; Sun, Changzheng; Hao, Zhibiao; Xiong, Bing

    2016-05-16

    Indium tin oxide (ITO)/ indium oxide (InxO) double layer structure was adopted as the transparent conduction and light scattering function layer to improve the light extraction efficiency of the GaN-based blue LEDs. The double layer structure was first deposited in one run by electron beam evaporation using ITO and Indium as the source respectively, and then annealed in an oxygen environment. This method can fabricate transparent electrode with microstructure and low specific contact resistivity one time free from lithography and etching, which makes the fabrication process simple and at a ower cost. For the 220 nm ITO/ 170 nm InxO double layer sample annealed at 600°C for 15 min in oxygen, measurement results show that its root mean square of roughness of the surface microstructure can be as high as 85.2 nm which introduces the strongest light scattering. Its light transmittance at 450 nm can maintain 92.4%. At the same time, it can realize lower specific contact resistivity with p-InGaN. Compared with the GaN-based blue LEDs with only 220 nm ITO electrode, the light output power of the LEDs with 220 nm ITO/ 170 nm InxO double layer structure can be increased about 58.8%, and working voltage at 20 mA injection current is decreased about 0.23 V due to the enhanced current spreading capability. The light output power improvement is also theoretically convinced by finite difference time domain simulations. PMID:27409953

  17. Promoting protein self-association in non-glycosylated Thermomyces lanuginosus lipase based on crystal lattice contacts.

    Science.gov (United States)

    Madsen, Jens Kvist; Sørensen, Thomas Rebsdorf; Kaspersen, Jørn Døvling; Silow, Maria Berggård; Vind, Jesper; Pedersen, Jan Skov; Svendsen, Allan; Otzen, Daniel E

    2015-12-01

    We have used the crystal structure of Thermomyces lanuginosus lipase (TlL) to identify and strengthen potential protein-protein interaction sites in solution. As wildtype we used a deglycosylated mutant of TlL (N33Q). We designed a number of TlL mutants to promote interactions via interfaces detected in the crystal-lattice structure, through strengthening of hydrophobic, polar or electrostatic contacts or truncation of sterically blocking residues. We identify a mutant predicted to lead to increased interfacial hydrophobic contacts (N92F) that shows markedly increased self-association properties on native gradient gels. While wildtype TlL mainly forms monomer and 2M) of urea to dissociate. We conclude that crystal lattice contacts are a good starting point for design strategies to promote protein self-association. PMID:26431886

  18. Identification of Protein-Protein Interactions via a Novel Matrix-Based Sequence Representation Model with Amino Acid Contact Information.

    Science.gov (United States)

    Ding, Yijie; Tang, Jijun; Guo, Fei

    2016-01-01

    Identification of protein-protein interactions (PPIs) is a difficult and important problem in biology. Since experimental methods for predicting PPIs are both expensive and time-consuming, many computational methods have been developed to predict PPIs and interaction networks, which can be used to complement experimental approaches. However, these methods have limitations to overcome. They need a large number of homology proteins or literature to be applied in their method. In this paper, we propose a novel matrix-based protein sequence representation approach to predict PPIs, using an ensemble learning method for classification. We construct the matrix of Amino Acid Contact (AAC), based on the statistical analysis of residue-pairing frequencies in a database of 6323 protein-protein complexes. We first represent the protein sequence as a Substitution Matrix Representation (SMR) matrix. Then, the feature vector is extracted by applying algorithms of Histogram of Oriented Gradient (HOG) and Singular Value Decomposition (SVD) on the SMR matrix. Finally, we feed the feature vector into a Random Forest (RF) for judging interaction pairs and non-interaction pairs. Our method is applied to several PPI datasets to evaluate its performance. On the S . c e r e v i s i a e dataset, our method achieves 94 . 83 % accuracy and 92 . 40 % sensitivity. Compared with existing methods, and the accuracy of our method is increased by 0 . 11 percentage points. On the H . p y l o r i dataset, our method achieves 89 . 06 % accuracy and 88 . 15 % sensitivity, the accuracy of our method is increased by 0 . 76 % . On the H u m a n PPI dataset, our method achieves 97 . 60 % accuracy and 96 . 37 % sensitivity, and the accuracy of our method is increased by 1 . 30 % . In addition, we test our method on a very important PPI network, and it achieves 92 . 71 % accuracy. In the Wnt-related network, the accuracy of our method is increased by 16 . 67 % . The source code and all datasets are available

  19. 基于ANSYS的角接触混合陶瓷球轴承接触分析%Contact Analysis of Angular Contact Hybrid Ceramic Ball Bearing Based on ANSYS

    Institute of Scientific and Technical Information of China (English)

    沈禾凯; 张淳; 郑甲红

    2011-01-01

    This aritcal takes the angular contact hybrid ceramic ball bearing whose specification is VEX65/NS 7CE1 as zhe research object, establishes analytical model based on FEA of ANSYS, gives a minute description to contact analysis of ball bearing about the logical simplification of the model and the set up of boundary conditions than solves the problem,thus it has important guiding significance on the further study on failure damage and on Rolling Bearing-Spindle System.%以VEX65/NS 7CE1角接触陶瓷球轴承为研究对象,建立了基于ANSYS的有限元分析模型,对轴承的接触分析中模型的合理简化和边界条件的设定作了详尽的说明并进而求解.其结果对进一步研究陶瓷球轴承的疲劳破坏及转子系统的研究提供了重要指导基础.

  20. ALLERGIC CONTACT DERMATITIS

    Directory of Open Access Journals (Sweden)

    Trisna Yuliharti Tersinanda

    2013-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Allergic contact dermatitis is an immunologic reaction that tends to involve the surrounding skin and may even spread beyond affected sites. This skin disease is one of the more frequent, and costly dermatologic problems. Recent data from United Kingdom and United States suggest that the percentage of occupational contact dermatitis due to allergy may be much higher, thus raising the economic impact of occupational allergic contact dermatitis. There is not enough data about the epidemiology of allergic contact dermatitis in Indonesia, however based on research that include beautician in Denpasar, about 27,6 percent had side effect of cosmetics, which is 25,4 percent of it manifested as allergic contact dermatitis. Diagnosis of allergic contact dermatitis is based on anamnesis, physical examination, patch test, and this disease should be distinguished from other eczematous skin disease. The management is prevention of allergen exposure, symptomatic treatment, and physicochemical barrier /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  1. Lipstick Induced Contact Leucoderma

    OpenAIRE

    Gupta Lalit Kumar; Jain Suresh Kumar; Khare Ashok Kumar

    2001-01-01

    Lipstick is a commonly used cosmetic. Its use may sometimes lead to contact dermatitis. Contact leucoderma to lipsticks however, is not common. We report a patient developing contact leucoderma to lipstick in association with contact dermatitis.

  2. Lipstick Induced Contact Leucoderma

    Directory of Open Access Journals (Sweden)

    Gupta Lalit Kumar

    2001-01-01

    Full Text Available Lipstick is a commonly used cosmetic. Its use may sometimes lead to contact dermatitis. Contact leucoderma to lipsticks however, is not common. We report a patient developing contact leucoderma to lipstick in association with contact dermatitis.

  3. Technological change of the energy innovation system: From oil-based to bio-based energy

    Energy Technology Data Exchange (ETDEWEB)

    Wonglimpiyarat, Jarunee [College of Innovation, Thammasat University, Anekprasong Building 7th Fl., Prachan Rd., Bangkok 10200 (Thailand)

    2010-03-15

    This paper concerns the structural developments and the direction of technological change of the energy innovation system, based on the studies of Kuhn's model of scientific change and Schumpeter's model of technological change. The paper uses the case study of Thai government agencies for understanding the way governments can facilitate technological innovation. The analyses are based on a pre-foresight exercise to examine the potential of the bio-based energy and investigate a set of development policies necessary for the direction of energy system development. The results have shown that bio-based energy is seen as the next new wave for future businesses and one of the solutions to the problem of high oil prices to improve the world's economic security and sustainable development. (author)

  4. A Population-Based Study of Childhood Sexual Contact in China: Prevalence and Long-Term Consequences

    Science.gov (United States)

    Luo, Ye; Parish, William L.; Laumann, Edward O.

    2008-01-01

    Objectives: This study provides national estimates of the prevalence of childhood sexual contact and its association with sexual well-being and psychological distress among adults in China. Method: A national stratified probability sample of 1,519 women and 1,475 men aged 20-64 years in urban China completed a computer-administered survey in…

  5. Computing Contact Stresses In Gear Teeth

    Science.gov (United States)

    Oswald, Fred B.; Somprakit, Paisan; Huston, Ronald L.

    1995-01-01

    Improved method of computing contact stresses in gear teeth accounts for complicating effects like those of static and sliding friction. Provides iterative procedure for determination of contact region and nodal contact forces along with contact stresses. Method based on equations and computational procedure incorporating these effects routinely.

  6. Ferrofluid based micro-electrical energy harvesting

    Science.gov (United States)

    Purohit, Viswas; Mazumder, Baishakhi; Jena, Grishma; Mishra, Madhusha; Materials Department, University of California, Santa Barbara, CA93106 Collaboration

    2013-03-01

    Innovations in energy harvesting have seen a quantum leap in the last decade. With the introduction of low energy devices in the market, micro energy harvesting units are being explored with much vigor. One of the recent areas of micro energy scavenging is the exploitation of existing vibrational energy and the use of various mechanical motions for the same, useful for low power consumption devices. Ferrofluids are liquids containing magnetic materials having nano-scale permanent magnetic dipoles. The present work explores the possibility of the use of this property for generation of electricity. Since the power generation is through a liquid material, it can take any shape as well as response to small acceleration levels. In this work, an electromagnet-based micropower generator is proposed to utilize the sloshing of the ferrofluid within a controlled chamber which moves to different low frequencies. As compared to permanent magnet units researched previously, ferrofluids can be placed in the smallest of containers of different shapes, thereby giving an output in response to the slightest change in motion. Mechanical motion from 1- 20 Hz was able to give an output voltage in mV's. In this paper, the efficiency and feasibility of such a system is demonstrated.

  7. Characterization of AlGaN-based metal-semiconductor solar-blind UV photodiodes with IrO{sub 2} Schottky contacts

    Energy Technology Data Exchange (ETDEWEB)

    Schalkwyk, L. van, E-mail: Louwrens.VanSchalkwyk@up.ac.za [Department of Physics, University of Pretoria, Private bag X20, Hatfield 0028 (South Africa); Meyer, W.E.; Auret, F.D.; Nel, J.M.; Ngoepe, P.N.M.; Diale, M. [Department of Physics, University of Pretoria, Private bag X20, Hatfield 0028 (South Africa)

    2012-05-15

    Intrinsically solar-blind ultraviolet (UV) AlGaN-based Schottky photodiodes were fabricated using Iridium oxide (IrO{sub 2}) as the Schottky barrier material. The Ir Schottky contacts were annealed at 700 Degree-Sign C under O{sub 2} ambient and the photodiodes characterized with an optoelectronic system. The main parameters extracted from I-V measurements were an average ideality factor of 1.38, a Schottky barrier height of 1.52 eV, a reverse leakage current density at -1 V bias of 5.2 nA/cm{sup 2} and series resistance of 250{Omega}. After spectral characterization, it was found that annealing, alone, of the Ir contact to form the more UV transmissive IrO{sub 2} does not always improve the responsivity. The deposition of a Au probe contact on the IrO{sub 2} contact increased the responsivity from 40 mA/W to 52 mA/W at 275 nm with respect to the annealed Ir contact. However, the ideality factor degraded to 1.57, Schottky barrier height lowered to 1.19 eV, reverse leakage current density increased to 49 nA/cm{sup 2} and series resistance decreased to 100{Omega} with the addition of the Au contact. The radiation hardness of AlGaN was also confirmed after studying the effects of 5.4 MeV He-ion irradiation using {sup 241}Am for a total fluence of 3 Multiplication-Sign 10{sup 13} cm{sup -2}.

  8. Bluetooth low energy based ticketing systems

    OpenAIRE

    Kuchimanchi, Sriharsha

    2015-01-01

    This thesis proposes a Bluetooth Low Energy (BLE) based payment solution for public transportation. The thesis first reviews some of the ‘Mobile payment solutions´. Traditionally, these services have revolved around technologies like Barcodes, Quick Response (QR) codes, Short Messaging Services (SMS) etc. However, with the advent of smartphones equipped with Bluetooth controllers and security chips, a number of innovative payment services are being studied. Furthermore, this thesis a...

  9. Sustainable Urban Regeneration Based on Energy Balance

    OpenAIRE

    Sacha Silvester; Han Brezet; Arjan van Timmeren; Jonna Zwetsloot

    2012-01-01

    In this paper, results are reported of a technology assessment of the use and integration of decentralized energy systems and storage devices in an urban renewal area. First the general context of a different approach based on 'rethinking' and the incorporation of ongoing integration of coming economical and environmental interests on infrastructure, in relation to the sustainable urban development and regeneration from the perspective of the tripod people, technology and design is ...

  10. The Nuclear Contact Exists

    CERN Document Server

    Hen, O; Piasetzky, E; Miller, G A; Sargsian, M M

    2014-01-01

    Many-body systems of strongly interacting Fermions are ubiquitous in nature, ranging from High-Tc superconductors and ultra-cold atomic gases to atomic nuclei and neutron stars. Theoretical predictions, recently verified by measurements on ultra-cold atomic gases, show that under certain conditions the universal behavior of systems composed of two kinds of fermions can be described using a single parameter, simply called the contact, which is a measure of the number of different-fermion pairs in close proximity. This paper discusses the relevance of the contact for very different systems: atomic nuclei, made of strongly-interacting neutrons and protons. Here we show that the high-momentum distributions of protons and neutrons in nuclei, dominated by correlated proton-neutron pairs mainly in a spin-triplet state, have the same momentum dependence as those of cold atoms, with a strength described by the contact. We use high-energy electron scattering data to extract a value for the nuclear contact consistent wi...

  11. Evaluation of biomass combustion based energy systems by cumulative energy demand and energy yield coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T.; Oser, M.

    2004-07-01

    This final report prepared for the International Energy Agency (IEA) Bioenergy Task 32 presents a method for a comparison of different energy systems with respect to the overall energy yield during their life cycles. For this purpose, the Cumulative Energy Demand (CED) based on primary energy and the Energy Yield Factor (EYC) are introduced and determined for the following scenarios: Log wood, wood chips, and wood pellets for residential heating and - except for log wood - also for district heating. As an alternative to heat production, power production via combustion and use of the electricity for decentralised heat pumps is also looked at. The evaluation and comparison of both the EYC for all fuels and the EYC{sub N}R for the non-renewable part enables a ranking of energy systems without a subjective weighing of non-renewable and renewable fuels to be made. For a sustainable energy supply, it is proposed to implement renewable energy systems in future which achieve an energy yield EYC{sub N}R of at least greater than 2 but favourably greater than 5. The evaluation of the different scenarios presented is proposed as the future basis for the choice of the most efficient energy systems based on biomass combustion.

  12. Dynamics of social contagions with limited contact capacity

    CERN Document Server

    Wang, Wei; Zhu, Yu-Xiao; Tang, Ming; Zhang, Yi-Cheng

    2015-01-01

    Individuals are always limited by some inelastic resources, such as time and energy, which restrict them to dedicate to social interaction and limit their contact capacity. Contact capacity plays an important role in dynamics of social contagions, which so far has eluded theoretical analysis. In this paper, we first propose a non-Markovian model to understand the effects of contact capacity on social contagions, in which each individual can only contact and transmit the information to a finite number of neighbors. We then develop a heterogeneous edge-based compartmental theory for this model, and a remarkable agreement with simulations is obtained. Through theory and simulations, we find that enlarging the contact capacity makes the network more fragile to behavior spreading. Interestingly, we find that both the continuous and discontinuous dependence of the final adoption size on the information transmission probability can arise. And there is a crossover phenomenon between the two types of dependence. More ...

  13. Ohmic contacts with ultra-low optical loss on heavily doped n-type InGaAs and InGaAsP for InP-based photonic membranes

    OpenAIRE

    Shen, L Longfei; Veldhoven, van, A.D.; Jiao, Y Yuqing; Dolores Calzadilla, VM Victor; Tol, van der, JJGM Jos; Roelkens, G Gunther; Smit, MK Meint

    2016-01-01

    In this paper, we present significant reductions of optical losses and contact resistances in AgGe-based ohmic contacts to InP membranes. Due to the high solubility of Si in InGaAs and InGaAsP, heavily doped n-type contact layers are grown on InP wafers. This high doping concentration gives rise to annealing-free ohmic contacts and low contact resistances at the level of 10(-7) Omega cm(2). It also leads to strong band-filling effects in InGaAs and InGaAsP, which result in low optical absorpt...

  14. Solar Energy Based Automated Irrigation System

    Directory of Open Access Journals (Sweden)

    Prof. Lodhi A. K.

    2013-09-01

    Full Text Available In the field of agriculture, use of proper method of irrigation is important because the main reason is the lack of rains {&} scarcity of land reservoir water. The continuous extraction of water from earth is reducing the water level due to which lot of land is coming slowly in the zones of un-irrigated land. Another very important reason of this is due to unplanned use of water due to which a significant amount of water goes waste. For this purpose; we use this automatic plant irrigation system. In this project we use solar energy which is used to operate the irrigation pump. The circuit comprises of sensor parts built using op-amp IC LM358. Op-amp are configured here as a comparator. Two stiff copper wires are inserted in the soil to sense whether the soil is wet or dry. The Microcontroller is used to control the whole system by monitoring the sensors and when sensors sense the dry condition then the microcontroller will send command to relay driver IC the contacts of which are used to switch on the motor and it will switch off the motor when all the sensors are in wet condition. The microcontroller does the above job as it receives the signal from the sensors through the output of the comparator, and these signals operate under the control of software which is stored in ROM of the Microcontroller. The condition of the pump i.e., ON/OFF is displayed on a 16X2 LCD

  15. Temperature dependence of energy dissipation on NaCl(001) in non-contact atomic force microscopy

    Science.gov (United States)

    Langewisch, G.; Fuchs, H.; Schirmeisen, A.

    2010-08-01

    The dissipative tip-sample interactions are measured by dynamic force spectroscopy for silicon tips on NaCl(001) in ultrahigh vacuum in the attractive and repulsive force regimes. Force and dissipation versus distance curves were obtained for different sample temperatures ranging from 35 to 285 K. Detailed comparison in different distance regimes shows that neither the force nor energy dissipation exhibits a systematic variation with sample temperature.

  16. Optimization of the Energy Level Alignment between the Photoactive Layer and the Cathode Contact Utilizing Solution-Processed Hafnium Acetylacetonate as Buffer Layer for Efficient Polymer Solar Cells.

    Science.gov (United States)

    Yu, Lu; Li, Qiuxiang; Shi, Zhenzhen; Liu, Hao; Wang, Yaping; Wang, Fuzhi; Zhang, Bing; Dai, Songyuan; Lin, Jun; Tan, Zhan'ao

    2016-01-13

    The insertion of an appropriate interfacial buffer layer between the photoactive layer and the contact electrodes makes a great impact on the performance of polymer solar cells (PSCs). Ideal interfacial buffer layers could minimize the interfacial traps and the interfacial barriers caused by the incompatibility between the photoactive layer and the electrodes. In this work, we utilized solution-processed hafnium(IV) acetylacetonate (Hf(acac)4) as an effective cathode buffer layer (CBL) in PSCs to optimize the energy level alignment between the photoactive layer and the cathode contact, with the short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF) all simultaneously improved with Hf(acac)4 CBL, leading to enhanced power conversion efficiencies (PCEs). Ultraviolet photoemission spectroscopy (UPS) and scanning Kelvin probe microscopy (SKPM) were performed to confirm that the interfacial dipoles were formed with the same orientation direction as the built-in potential between the photoactive layer and Hf(acac)4 CBL, benefiting the exciton separation and electron transport/extraction. In addition, the optical characteristics and surface morphology of the Hf(acac)4 CBL were also investigated.

  17. Reliability of video-based identification of footstrike pattern and video time frame at initial contact in recreational runners

    DEFF Research Database (Denmark)

    Damsted, Camma; Larsen, L H; Nielsen, R.O.

    2015-01-01

    INTRODUCTION: Two-dimensional video recordings are used in clinical practice to identify footstrike pattern. However, knowledge about the reliability of this method of identification is limited. OBJECTIVE: To evaluate intra- and inter-rater reliability of visual identification of footstrike pattern...... and video time frame at initial contact during treadmill running using two-dimensional (2D) video recordings. METHODS: Thirty-one recreational runners were recorded twice, 1 week apart, with a high-speed video camera. Two blinded raters evaluated each video twice with an interval of at least 14 days...... in 36% of the identifications (kappa=0.41). The 95% limits of agreement for identification of video time frame at initial contact may, at times, allow for different identification of footstrike pattern. Clinicians should, therefore, be encouraged to continue using clinical 2D video setups for intra...

  18. Open-cycle magnetohydrodynamic power plant based upon direct-contact closed-loop high-temperature heat exchanger

    Science.gov (United States)

    Berry, Gregory F.; Minkov, Vladimir; Petrick, Michael

    1988-01-01

    A magnetohydrodynamic (MHD) power generating system in which ionized combustion gases with slag and seed are discharged from an MHD combustor and pressurized high temperature inlet air is introduced into the combustor for supporting fuel combustion at high temperatures necessary to ionize the combustion gases, and including a heat exchanger in the form of a continuous loop with a circulating heat transfer liquid such as copper oxide. The heat exchanger has an upper horizontal channel for providing direct contact between the heat transfer liquid and the combustion gases to cool the gases and condense the slag which thereupon floats on the heat transfer liquid and can be removed from the channel, and a lower horizontal channel for providing direct contact between the heat transfer liquid and pressurized air for preheating the inlet air. The system further includes a seed separator downstream of the heat exchanger.

  19. Cantilever-based electret energy harvesters

    International Nuclear Information System (INIS)

    Integration of structures and functions has permitted the electricity consumption of sensors, actuators and electronic devices to be reduced. Therefore, it is now possible to imagine low-consumption devices able to harvest energy from their surrounding environment. One way to proceed is to develop converters able to turn mechanical energy, such as vibrations, into electricity: this paper focuses on electrostatic converters using electrets. We develop an accurate analytical model of a simple but efficient cantilever-based electret energy harvester. We prove that with vibrations of 0.1g (∼1 m s−2), it is theoretically possible to harvest up to 30 µW per gram of mobile mass. This power corresponds to the maximum output power of a resonant energy harvester according to the model of William and Yates. Simulation results are validated by experimental measurements, raising at the same time the large impact of parasitic capacitances on the output power. Therefore, we 'only' managed to harvest 10 µW per gram of mobile mass, but according to our factor of merit, this is among the best results so far achieved

  20. A Simple Approach to Characterize Gas-Aqueous Liquid Two-phase Flow Configuration Based on Discrete Solid-Liquid Contact Electrification.

    Science.gov (United States)

    Choi, Dongwhi; Lee, Donghyeon; Kim, Dong Sung

    2015-10-14

    In this study, we first suggest a simple approach to characterize configuration of gas-aqueous liquid two-phase flow based on discrete solid-liquid contact electrification, which is a newly defined concept as a sequential process of solid-liquid contact and successive detachment of the contact liquid from the solid surface. This approach exhibits several advantages such as simple operation, precise measurement, and cost-effectiveness. By using electric potential that is spontaneously generated by discrete solid-liquid contact electrification, the configurations of the gas-aqueous liquid two-phase flow such as size of a gas slug and flow rate are precisely characterized. According to the experimental and numerical analyses on parameters that affect electric potential, gas slugs have been verified to behave similarly to point electric charges when the measuring point of the electric potential is far enough from the gas slug. In addition, the configuration of the gas-aqueous liquid two-phase microfluidic system with multiple gas slugs is also characterized by using the presented approach. For a proof-of-concept demonstration of using the proposed approach in a self-triggered sensor, a gas slug detector with a counter system is developed to show its practicality and applicability.

  1. Decoupling contact and mirror: an effective way to improve the reflector for flip-chip InGaN/GaN-based light-emitting diodes

    Science.gov (United States)

    Zhu, Binbin; Liu, Wei; Lu, Shunpeng; Zhang, Yiping; Hasanov, Namig; Zhang, Xueliang; Ji, Yun; Zhang, Zi-Hui; Tiam Tan, Swee; Liu, Hongfei; Demir, Hilmi Volkan

    2016-07-01

    In the conventional fabrication process of the widely-adopted Ni/Ag/Ti/Au reflector for InGaN/GaN-based flip-chip light-emitting diodes (LEDs), the contact and the mirror are entangled together with contrary processing conditions which set constraints to the device performance severely. Here we first report the concept and its effectiveness of decoupling the contact formation and the mirror construction. The ohmic contact is first formed by depositing and annealing an extremely thin layer of Ni/Ag on top of p-GaN. The mirror construction is then carried out by depositing thick layer of Ag/Ti/Au without any annealing. Compared with the conventional fabrication method of the reflector, by which the whole stack of Ni/Ag/Ti/Au is deposited and annealed together, the optical output power is improved by more than 70% at 350 mA without compromising the electrical performance. The mechanism of decoupling the contact and the mirror is analyzed with the assistance of contactless sheet resistance measurement and secondary ion mass spectrometry (SIMS) depth profile analysis.

  2. Non-contact video-based vital sign monitoring using ambient light and auto-regressive models.

    OpenAIRE

    Tarassenko, L; Villarroel, M; Guazzi, A; Jorge, J; Clifton, DA; Pugh, C.

    2014-01-01

    Remote sensing of the reflectance photoplethysmogram using a video camera typically positioned 1 m away from the patient's face is a promising method for monitoring the vital signs of patients without attaching any electrodes or sensors to them. Most of the papers in the literature on non-contact vital sign monitoring report results on human volunteers in controlled environments. We have been able to obtain estimates of heart rate and respiratory rate and preliminary results on changes in oxy...

  3. A Study of a Handrim-Activated Power-Assist Wheelchair Based on a Non-Contact Torque Sensor

    Science.gov (United States)

    Nam, Ki-Tae; Jang, Dae-Jin; Kim, Yong Chol; Heo, Yoon; Hong, Eung-Pyo

    2016-01-01

    Demand for wheelchairs is increasing with growing numbers of aged and disabled persons. Manual wheelchairs are the most commonly used assistive device for mobility because they are convenient to transport. Manual wheelchairs have several advantages but are not easy to use for the elderly or those who lack muscular strength. Therefore, handrim-activated power-assist wheelchairs (HAPAW) that can aid driving power with a motor by detecting user driving intentions through the handrim are being researched. This research will be on HAPAW that judge user driving intentions by using non-contact torque sensors. To deliver the desired motion, which is sensed from handrim rotation relative to a fixed controller, a new driving wheel mechanism is designed by applying a non-contact torque sensor, and corresponding torques are simulated. Torques are measured by a driving wheel prototype and compared with simulation results. The HAPAW prototype was developed using the wheels and a driving control algorithm that uses left and right input torques and time differences are used to check if the non-contact torque sensor can distinguish users’ driving intentions. Through this procedure, it was confirmed that the proposed sensor can be used effectively in HAPAW. PMID:27509508

  4. Structural changes of electron and ion beam-deposited contacts in annealed carbon-based electrical devices

    KAUST Repository

    Batra, Nitin M

    2015-10-09

    The use of electron and ion beam deposition to make devices containing discrete nanostructures as interconnectors is a well-known nanofabrication process. Classically, one-dimensional materials such as carbon nanotubes (CNTs) have been electrically characterized by resorting to these beam deposition methods. While much attention has been given to the interconnectors, less is known about the contacting electrodes (or leads). In particular, the structure and chemistry of the electrode–interconnector interface is a topic that deserves more attention, as it is critical to understand the device behavior. Here, the structure and chemistry of Pt electrodes, deposited either with electron or ion beams and contacted to a CNT, are analyzed before and after thermally annealing the device in a vacuum. Free-standing Pt nanorods, acting as beam-deposited electrode models, are also characterized pre- and post-annealing. Overall, the as-deposited leads contain a non-negligible amount of amorphous carbon that is consolidated, upon heating, as a partially graphitized outer shell enveloping a Pt core. This observation raises pertinent questions regarding the definition of electrode–nanostructure interfaces in electrical devices, in particular long-standing assumptions of metal-CNT contacts fabricated by direct beam deposition methods.

  5. A Study of a Handrim-Activated Power-Assist Wheelchair Based on a Non-Contact Torque Sensor

    Directory of Open Access Journals (Sweden)

    Ki-Tae Nam

    2016-08-01

    Full Text Available Demand for wheelchairs is increasing with growing numbers of aged and disabled persons. Manual wheelchairs are the most commonly used assistive device for mobility because they are convenient to transport. Manual wheelchairs have several advantages but are not easy to use for the elderly or those who lack muscular strength. Therefore, handrim-activated power-assist wheelchairs (HAPAW that can aid driving power with a motor by detecting user driving intentions through the handrim are being researched. This research will be on HAPAW that judge user driving intentions by using non-contact torque sensors. To deliver the desired motion, which is sensed from handrim rotation relative to a fixed controller, a new driving wheel mechanism is designed by applying a non-contact torque sensor, and corresponding torques are simulated. Torques are measured by a driving wheel prototype and compared with simulation results. The HAPAW prototype was developed using the wheels and a driving control algorithm that uses left and right input torques and time differences are used to check if the non-contact torque sensor can distinguish users’ driving intentions. Through this procedure, it was confirmed that the proposed sensor can be used effectively in HAPAW.

  6. Force distribution in granular media studied by an energy method based on statistical mechanics

    CERN Document Server

    Galindo-Torres, S A

    2010-01-01

    In the present letter a method to find a proper expression for the force distribution inside a granular sample in static equilibrium is proposed. The method is based in statistical mechanics and the force distribution is obtained by studying how the potential elastic energy is divided among the different contacts between grains. It is found with DEM simulations with spheres that the elastic potential energy distribution follows a Bose Einstein law from which the force distribution is deduced. The present letter open a way in which granular materials can be studied with the tools provided by statistical mechanics.

  7. Influence of Inner Transducer Properties on EMF Response and Stability of Solid-Contact Anion Selective Membrane Electrodes Based on Metalloporphyrin Ionophores

    OpenAIRE

    Górski, Łukasz; Matusevich, Alexey; Pietrzak, Mariusz; Wang, Lin; Meyerhoff, Mark E.; Malinowska, Elżbieta

    2009-01-01

    The performance of solid-contact/coated wire type electrodes with plasticized PVC membranes containing metalloporphyrins as anion selective ionophores is reported. The membranes are deposited on transducers based on graphite pastes and graphite rods. The hydrophobicity of the underlying conductive transducer surface is found to be a key factor that influences the formation of an aqueous layer beneath the polymer film. Elimination of this ill-defined water layer greatly improves the electroche...

  8. Scientific Opinion on the safety evaluation of a time-temperature indicator system, based on Carnobacterium maltaromaticum and acid fuchsin for use in food contact materials

    OpenAIRE

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF)

    2013-01-01

    This scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety evaluation of a system based on Carnobacterium maltaromaticum and a colour change indicator, acid fuchsin (CAS number 3244-88-0, FCM Substance No 01033), used as a time-temperature indicator on the packaging of chilled food. The micro-organism, the indicator and a nutritive medium gel are incorporated in a multilayer plastic sachet glued onto the outer layer of t...

  9. Does the training of mentors increase the contact frequency and the quality of support in a portfolio-based teaching module?

    OpenAIRE

    Schmidt, Anita; Schwedler, Andreas; Hahn, Eckhart G

    2010-01-01

    Introduction: All over the world, mentors are employed more and more for portfolio-based training modules in order to support the learner’s learning- and reflection process. Within the final year of medical education, tertial internal medicine, the University Hospital of Erlangen, Department of Medicine 1 offered trainings for mentors. In the framework of the student’s evaluation of this training period it was asked whether and what kind of effect the mentor training has had on the contact fr...

  10. Ion Implanted Passivated Contacts for Interdigitated Back Contacted Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Young, David L.; Nemeth, William; LaSalvia, Vincenzo; Reedy, Robert; Bateman, Nicholas; Stradins, Pauls

    2015-06-14

    We describe work towards an interdigitated back contacted (IBC) solar cell utilizing ion implanted, passivated contacts. Formation of electron and hole passivated contacts to n-type CZ wafers using tunneling SiO2 and ion implanted amorphous silicon (a-Si) are described. P and B were ion implanted into intrinsic amorphous Si films at several doses and energies. A series of post-implant anneals showed that the passivation quality improved with increasing annealing temperatures up to 900 degrees C. The recombination parameter, Jo, as measured by a Sinton lifetime tester, was Jo ~ 14 fA/cm2 for Si:P, and Jo ~ 56 fA/cm2 for Si:B contacts. The contact resistivity for the passivated contacts, as measured by TLM patterns, was 14 milliohm-cm2 for the n-type contact and 0.6 milliohm-cm2 for the p-type contact. These Jo and pcontact values are encouraging for forming IBC cells using ion implantation to spatially define dopants.

  11. Thermodynamic origin of the contact

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Rochin, Victor, E-mail: romero@fisica.unam.mx [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, 01000 Mexico D.F. (Mexico)

    2011-05-14

    As can be inferred from present experiments in ultracold gases, the scattering length is a quantity that determines the thermodynamic state of the gas. As such, a conjugate thermodynamic variable to it exists. Here, we show that the recently introduced contact is the conjugate of the inverse of the scattering length. We find that this identification, in addition to well-known approximations, allows for a derivation of three of the most relevant results concerning the contact, namely its relation to the adiabatic change of the energy, the general form of the energy and the generalized virial theorem. We find that the current identification of the contact variable depends on the use of the contact approximation for the intermolecular potential but it is independent of whether the gas is made out of fermions or bosons and of the strength of the interaction.

  12. A plasmacytoid dendritic cell (CD123+/CD11c-) based assay system to predict contact allergenicity of chemicals

    International Nuclear Information System (INIS)

    A predictive allergenicity test system for assessing the contact allergenicity of chemicals is needed by the cosmetic and pharmaceutical industry to monitor product safety in the marketplace. Development of such non-animal alternative assay systems for skin sensitization and hazard identification has been pursued by policy makers and regulatory agencies. We investigated whether phenotypic and functional changes to a subset of dendritic cells (DC), plasmacytoid DC (pDC), could be used to identify contact allergens. To achieve this goal, normal human DC were generated from CD34+ progenitor cells and cryopreserved. Frozen DC were thawed and the pDC fraction (CD123+/CD11c-) was harvested using FACS sorting. The pDC were cultured, expanded, and exposed to chemical allergens (N = 26) or non-allergens (N = 22). Concentrations of each chemical that resulted in >50% viability was determined using FACS analysis of propidium iodide stained cells using pDC from 2 to 5 donors. Expression of the surface marker, CD86, which has been implicated in dendritic cell maturation, was used as a marker of allergenicity. CD86 expression increased (≥1.5-fold) for 25 of 26 allergens (sensitivity = 96%) but did not increase for 19 of 22 non-allergens (specificity = 86%). In a direct comparison to historical data for the regulatory approved, mouse local lymph node assay (LLNA) for 23 allergens and 22 non-allergens, the pDC method had sensitivity and specificity of 96% and 86%, respectively, while the sensitivity and specificity of the LLNA assay was 83% and 82%, respectively. In conclusion, CD86 expression in pDC appears to be a sensitive and specific indicator to identify contact allergenicity. Such an assay method utilizing normal human cells will be useful for high throughput screening of chemicals for allergenicity.

  13. Ultraviolet GaN photodetectors on Si via oxide buffer heterostructures with integrated short period oxide-based distributed Bragg reflectors and leakage suppressing metal-oxide-semiconductor contacts

    Energy Technology Data Exchange (ETDEWEB)

    Szyszka, A., E-mail: szyszka@ihp-microelectronics.com, E-mail: adam.szyszka@pwr.wroc.pl [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wroclaw (Poland); Lupina, L.; Lupina, G.; Schubert, M. A.; Zaumseil, P. [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Haeberlen, M.; Storck, P.; Thapa, S. B. [Siltronic, Hanns-Seidel-Platz 4, 81737 München (Germany); Schroeder, T. [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); BTU Cottbus-Senftenberg, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

    2014-08-28

    Based on a novel double step oxide buffer heterostructure approach for GaN integration on Si, we present an optimized Metal-Semiconductor-Metal (MSM)-based Ultraviolet (UV) GaN photodetector system with integrated short-period (oxide/Si) Distributed Bragg Reflector (DBR) and leakage suppressing Metal-Oxide-Semiconductor (MOS) electrode contacts. In terms of structural properties, it is demonstrated by in-situ reflection high energy electron diffraction and transmission electron microscopy-energy dispersive x-ray studies that the DBR heterostructure layers grow with high thickness homogeneity and sharp interface structures sufficient for UV applications; only minor Si diffusion into the Y{sub 2}O{sub 3} films is detected under the applied thermal growth budget. As revealed by comparative high resolution x-ray diffraction studies on GaN/oxide buffer/Si systems with and without DBR systems, the final GaN layer structure quality is not significantly influenced by the growth of the integrated DBR heterostructure. In terms of optoelectronic properties, it is demonstrated that—with respect to the basic GaN/oxide/Si system without DBR—the insertion of (a) the DBR heterostructures and (b) dark current suppressing MOS contacts enhances the photoresponsivity below the GaN band-gap related UV cut-off energy by almost up to two orders of magnitude. Given the in-situ oxide passivation capability of grown GaN surfaces and the one order of magnitude lower number of superlattice layers in case of higher refractive index contrast (oxide/Si) systems with respect to classical III-N DBR superlattices, virtual GaN substrates on Si via functional oxide buffer systems are thus a promising robust approach for future GaN-based UV detector technologies.

  14. Value of the energy data base

    Energy Technology Data Exchange (ETDEWEB)

    King, D.W.; Griffiths, J.M.; Roderer, N.K.; Wiederkehr, R.R.V.

    1982-03-31

    An assessment was made of the Energy Data Base (EDB) of the Department of Energy's Technical Information Center (TIC). As the major resource containing access information to the world's energy literature, EDB products and services are used extensively by energy researchers to identify journal articles, technical reports and other items of potential utility in their work. The approach taken to assessing value begins with the measurement of extent of use of the EDB. Apparent value is measured in terms of willingness to pay. Consequential value is measured in terms of effect - for searching, the cost of reading which results; and for reading, the savings which result from the application of the information obtained in reading. Resulting estimates of value reflect value to the searchers, the reader, and the reader's organization or funding source. A survey of the 60,000 scientists and eingineers funded by the DOE shows that annually they read about 7.1 million journal articles and 6.6 million technical reports. A wide range of savings values were reported for one-fourth of all article readings and three-fourths of all report readings. There was an average savings of $590 per reading of all articles; there was an average savings of $1280 for technical reports. The total annual savings attributable to reading by DOE-funded scientists and engineers is estimated to be about $13 billion. An investment of $5.3 billion in the generation of information and about $500 million in processing and using information yields a partial return of about $13 billion. Overall, this partial return on investment is about 2.2 to 1. In determining the value of EDB only those searches and readings directly attributable to it are included in the analysis. The values are $20 million to the searchers, $117 million to the readers and $3.6 billion to DOE.

  15. Measurement of the quantum conductance of germanium by an electrochemical scanning tunneling microscope break junction based on a jump-to-contact mechanism.

    Science.gov (United States)

    Xie, Xufen; Yan, Jiawei; Liang, Jinghong; Li, Jijun; Zhang, Meng; Mao, Bingwei

    2013-10-01

    We present quantum conductance measurements of germanium by means of an electrochemical scanning tunneling microscope (STM) break junction based on a jump-to-contact mechanism. Germanium nanowires between a platinum/iridium tip and different substrates were constructed to measure the quantum conductance. By applying appropriate potentials to the substrate and the tip, the process of heterogeneous contact and homogeneous breakage was realized. Typical conductance traces exhibit steps at 0.025 and 0.05 G0. The conductance histogram indicates that the conductance of germanium nanowires is located between 0.02 and 0.15 G0 in the low-conductance region and is free from the influence of substrate materials. However, the distribution of conductance plateaus is too discrete to display distinct peaks in the conductance histogram of the high-conductance region. PMID:23704043

  16. A non-contact method based on multiple signal classification algorithm to reduce the measurement time for accurately heart rate detection

    Science.gov (United States)

    Bechet, P.; Mitran, R.; Munteanu, M.

    2013-08-01

    Non-contact methods for the assessment of vital signs are of great interest for specialists due to the benefits obtained in both medical and special applications, such as those for surveillance, monitoring, and search and rescue. This paper investigates the possibility of implementing a digital processing algorithm based on the MUSIC (Multiple Signal Classification) parametric spectral estimation in order to reduce the observation time needed to accurately measure the heart rate. It demonstrates that, by proper dimensioning the signal subspace, the MUSIC algorithm can be optimized in order to accurately assess the heart rate during an 8-28 s time interval. The validation of the processing algorithm performance was achieved by minimizing the mean error of the heart rate after performing simultaneous comparative measurements on several subjects. In order to calculate the error the reference value of heart rate was measured using a classic measurement system through direct contact.

  17. Adhesion in hydrogel contacts

    Science.gov (United States)

    Torres, J. R.; Jay, G. D.; Kim, K.-S.; Bothun, G. D.

    2016-05-01

    A generalized thermomechanical model for adhesion was developed to elucidate the mechanisms of dissipation within the viscoelastic bulk of a hyperelastic hydrogel. Results show that in addition to the expected energy release rate of interface formation, as well as the viscous flow dissipation, the bulk composition exhibits dissipation due to phase inhomogeneity morphological changes. The mixing thermodynamics of the matrix and solvent determines the dynamics of the phase inhomogeneities, which can enhance or disrupt adhesion. The model also accounts for the time-dependent behaviour. A parameter is proposed to discern the dominant dissipation mechanism in hydrogel contact detachment.

  18. Measurement of the friction coefficient of a fluctuating contact line using an AFM-based dual-mode mechanical resonator

    International Nuclear Information System (INIS)

    A dual-mode mechanical resonator using an atomic force microscope (AFM) as a force sensor is developed. The resonator consists of a long vertical glass fiber with one end glued onto a rectangular cantilever beam and the other end immersed through a liquid—air interface. By measuring the resonant spectrum of the modified AFM cantilever, one is able to accurately determine the longitudinal friction coefficient ζv along the fiber axis associated with the vertical oscillation of the hanging fiber and the traversal friction coefficient ζh perpendicular to the fiber axis associated with the horizontal swing of the fiber around its joint with the cantilever. The technique is tested by measurement of the friction coefficient of a fluctuating (and slipping) contact line between the glass fiber and the liquid interface. The experiment verifies the theory and demonstrates its applications. The dual-mode mechanical resonator provides a powerful tool for the study of the contact line dynamics and the rheological property of anisotropic fluids. (special topic — non-equilibrium phenomena in soft matters)

  19. Contact Lens Solution Toxicity

    Science.gov (United States)

    ... rash and rashes clinical tools newsletter | contact Share | Contact Lens Solution Toxicity Information for adults A A A This image shows a reaction to contact lens solution. The prominent blood vessels and redness ...

  20. Contact Lens Risks

    Science.gov (United States)

    ... Health and Consumer Devices Consumer Products Contact Lenses Contact Lens Risks Share Tweet Linkedin Pin it More ... redness blurred vision swelling pain Serious Hazards of Contact Lenses Symptoms of eye irritation can indicate a ...

  1. A Framework for Better Understanding and Enhancing Direct Contact Membrane Distillation (DCMD) in Terms of Module Design, Cost Analysis and Energy Required

    KAUST Repository

    AbuHannoud, Ali

    2011-07-01

    Water is becoming scarcer and several authors have highlighted the upcoming problem of higher water salinity and the difficulty of treating and discharging water. Moreover, current discoveries of problems with chemicals that have been used for pretreating or post-treating water alerted scientists to research better solutions to treat water. Membrane distillation (MD) is a promising technology that might replace current processes as it has lower pretreatment requirements combined with a tremendous ability to treat a wide range of feed sources while producing very high product quality. If it enters the market, it will have a big influence on all products, from food industry to spaceflight. However, there are several problems which make MD a hot topic for research. One of them is the question about the real cost of MD in terms of heating feed and cooling distillate over time with respect to product quantity and quality. In this work, extensive heating and cooling analyses are covered to answer this question in order to enhance the MD process. Results show energy cost to produce water and the main source of energy loss for direct contact membrane distillation (DCMD), and several suggestions are made in order to better understand and hence enhance the process.

  2. Investigation of the hydrophobic recovery of various polymeric biomaterials after 172 nm UV treatment using contact angle, surface free energy and XPS measurements

    International Nuclear Information System (INIS)

    Surface modification as a route to improving the performance of polymeric biomaterials is an area of much topical interest. Ultraviolet (UV) light treatment has received much attention, but polymers so treated revert to their original surface condition over a period of time-an effect known as hydrophobic recovery. It is important to develop an understanding of the underlying processes contributing to the effect, since it has an impact on the applicability of UV treatment. In this work a number of polymeric biomaterials were surface-modified using 172 nm UV light from an excimer lamp. The modified polymers were characterised using contact angle, surface free energy (SFE) measurements and X-Ray Photoelectron Spectroscopy (XPS) techniques. The wettability, variation in surface free energy and chemical functionality changes were analysed on the surfaces immediately after UV treatment and subsequently over a period of 28 days. It was noted that hydrophobic recovery proceeds at a different rate for each polymer, is generally a two-phase process and that surfaces are still more hydrophilic after 28 days than the original untreated state. XPS analysis reveals that particular chemical configurations move from the surface at a faster rate than others which may contribute to the two-phase nature of the process.

  3. Large deformation and adhesive contact studies of axisymmetric membranes.

    Science.gov (United States)

    Laprade, Evan J; Long, Rong; Pham, Jonathan T; Lawrence, Jimmy; Emrick, Todd; Crosby, Alfred J; Hui, Chung-Yuen; Shull, Kenneth R

    2013-02-01

    A model membrane contact system consisting of an acrylic copolymer membrane and a PDMS substrate was utilized to evaluate a recently developed nonlinear large-deformation adhesive contact analysis. Direct measurements of the local membrane apex strain during noncontact inflation indicated that the neo-Hookean model provides an accurate measure of membrane strain and supports its use as the strain energy function for the analysis. Two membrane contact geometries, exhibiting significantly different strain distributions during withdrawal, were investigated. The first examines the wet contact of an air pressurized membrane. The second looks at the dry contact of a fluid deformed membrane in which a stepper motor controls membrane-substrate separation. A time-dependent modulus emerges from the analysis, with principal tensions obtained from a comparison of predicted and experimental membrane profiles. The applicability of this numerical analysis for determining membrane tension, however, is limited by wrinkling instabilities and viscoelasticity. For this reason, a conceptually simpler method, based on the direct measurement of the membrane tension and contact angle, was also utilized. The traditional peel energy defined with this direct measurement accurately described the membrane/substrate adhesive interactions, giving well-defined peel energies that were independent of the detailed strain state of the membrane. PMID:23289644

  4. Contact Graph Routing

    Science.gov (United States)

    Burleigh, Scott C.

    2011-01-01

    Contact Graph Routing (CGR) is a dynamic routing system that computes routes through a time-varying topology of scheduled communication contacts in a network based on the DTN (Delay-Tolerant Networking) architecture. It is designed to enable dynamic selection of data transmission routes in a space network based on DTN. This dynamic responsiveness in route computation should be significantly more effective and less expensive than static routing, increasing total data return while at the same time reducing mission operations cost and risk. The basic strategy of CGR is to take advantage of the fact that, since flight mission communication operations are planned in detail, the communication routes between any pair of bundle agents in a population of nodes that have all been informed of one another's plans can be inferred from those plans rather than discovered via dialogue (which is impractical over long one-way-light-time space links). Messages that convey this planning information are used to construct contact graphs (time-varying models of network connectivity) from which CGR automatically computes efficient routes for bundles. Automatic route selection increases the flexibility and resilience of the space network, simplifying cross-support and reducing mission management costs. Note that there are no routing tables in Contact Graph Routing. The best route for a bundle destined for a given node may routinely be different from the best route for a different bundle destined for the same node, depending on bundle priority, bundle expiration time, and changes in the current lengths of transmission queues for neighboring nodes; routes must be computed individually for each bundle, from the Bundle Protocol agent's current network connectivity model for the bundle s destination node (the contact graph). Clearly this places a premium on optimizing the implementation of the route computation algorithm. The scalability of CGR to very large networks remains a research topic

  5. Contact handle decompositions

    OpenAIRE

    Özbağcı, Burak

    2009-01-01

    We review Giroux’s contact handles and contact handle attachments in dimension three and show that a bypass attachment consists of a pair of contact 1 and 2-handles. As an application we describe explicit contact handle decompositions of infinitely many pairwise non-isotopic overtwisted 3-spheres. We also give an alternative proof of the fact that every compact contact 3-manifold (closed or with convex boundary) admits a contact handle decomposition, which is a result originally due to Giroux.

  6. Tribological Behavior of Si3N4/Ti3SiC2 Contacts Lubricated by Lithium-Based Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Haizhong Wang

    2014-01-01

    Full Text Available The tribological performance of Si3N4 ball sliding against Ti3SiC2 disc lubricated by lithium-based ionic liquids (ILs was investigated using an Optimol SRV-IV oscillating reciprocating friction and wear tester at room temperature (RT and elevated temperature (100°C. Glycerol and the conventional imidazolium-based IL 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonylimide (L-F106 were used as references under the same experimental conditions. The results show that the lithium-based ILs had higher thermal stabilities than glycerol and lower costs associated with IL preparation than L-F106. The tribotest results show that the lithium-based ILs were effective in reducing the friction and wear of Si3N4/Ti3SiC2 contacts. [Li(urea]TFSI even produced better tribological properties than glycerol and L-F106 both at RT and 100°C. The SEM/EDS and XPS results reveal that the excellent tribological endurance of Si3N4/Ti3SiC2 contacts lubricated by lithium-based ILs was mainly attributed to the formation of surface protective films composed of various tribochemical products.

  7. Fabrication of three-dimensional and submicrometer-scaled microstructures based on metal contact printing and silicon bulk machining

    Science.gov (United States)

    Kao, Kuo-Lun; Chang, Cho-Wei; Lee, Yung-Chun

    2014-04-01

    This paper describes a method that contains a series of processes for producing three-dimensional (3-D) microstructures with a feature size in the submicrometer scale. It starts from using a metal contact printing lithography to pattern a thin metal film on the surface of a (100) silicon substrate. The metal film has a hole-array pattern with a hole diameter ranging from 300 nm to 800 nm and is used as an etching mask for silicon bulk machining to create concave pyramid-shaped surface microstructures. Using this bulk-machined silicon substrate as a template, polymer 3-D microstructures are replicated on top of a silicon dioxide (SiO) layer. Finally, through a dry etching process, 3-D microstructures with a profile similar to the replicated polymer microstructures are formed on the SiO layer. Potential applications of these fabricated SiO microstructures in the light-emitting diode industry will be addressed.

  8. Impact of DC-power during Mo back contact sputtering on the alkali distribution in Cu(In,Ga)Se{sub 2}-based thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lepetit, T., E-mail: thomas.lepetit@cnrs-imn.fr [Institut des Matériaux Jean Rouxel (IMN), UMR 6502 CNRS, 2 rue de la Houssinière BP 32229, 44322 Nantes Cedex 3 (France); Mangin, D. [Institut Jean Lamour, UMR 7198 CNRS — Université de Lorraine, Parc de Saurupt, CS 50840, 54011 Nancy Cedex (France); Gautron, E.; Tomassini, M.; Harel, S.; Arzel, L.; Barreau, N. [Institut des Matériaux Jean Rouxel (IMN), UMR 6502 CNRS, 2 rue de la Houssinière BP 32229, 44322 Nantes Cedex 3 (France)

    2015-05-01

    DC-sputtered Mo back contact layers were deposited on soda-lime glass (SLG) with different power densities applied on the Mo target to study its influence on the photovoltaic performance of Cu(In,Ga)Se{sub 2}-based (CIGSe) solar cell. CIGSe absorber was then deposited simultaneously on these SLG/Mo, following the 3-stage process. These devices have good but different photovoltaic performance (> 16% efficiency without MgF{sub 2} coating). To find a material origin, secondary ion mass spectroscopy (SIMS) profiles were carried out on complete cells, revealing that Na and K content and distribution in each layer depend on the deposition conditions of the back contact. Even before the CIGSe deposition and despite similar morphologies, Na content can vary 10-fold from one Mo layer to another. The same applies to the absorber; when grown on a different Mo they present the same grain boundary density but different alkali contents in bulk or at interfaces. This has an influence on the compositional grading in absorber, confirmed by X-ray diffraction and SIMS. - Highlights: • Mo films synthesized at different DC-power applied on the target during sputtering. • Similar macroscopic properties of Mo back contacts • The lowest alkali content in absorber with the highest DC-power applied during Mo sputtering.

  9. Low-ohmic-contact-resistance V-based electrode for n-type AlGaN with high AlN molar fraction

    Science.gov (United States)

    Mori, Kazuki; Takeda, Kunihiro; Kusafuka, Toshiki; Iwaya, Motoaki; Takeuchi, Tetsuya; Kamiyama, Satoshi; Akasaki, Isamu; Amano, Hiroshi

    2016-05-01

    We investigated a V-based electrode for the realization of low ohmic-contact resistivity in n-type AlGaN with a high AlN molar fraction characterized by the circular transmission line model. The contact resistivity of n-type Al0.62Ga0.38N prepared using the V/Al/Ni/Au electrode reached 1.13 × 10-6 Ω cm2. Using this electrode, we also demonstrated the fabrication of UV light-emitting diodes (LEDs) with an emission wavelength of approximately 300 nm. An operating voltage of LED prepared using a V/Al/Ni/Au electrode was 1.6 V lower at 100 mA current injection than that prepared using a Ti/Al/Ti/Au electrode, with a specific contact resistance of approximately 2.36 × 10-4 Ω cm2 for n-type Al0.62Ga0.38N.

  10. Dielectric Sensors Based on Electromagnetic Energy Tunneling

    Directory of Open Access Journals (Sweden)

    Omar Siddiqui

    2015-03-01

    Full Text Available We show that metallic wires embedded in narrow waveguide bends and channels demonstrate resonance behavior at specific frequencies. The electromagnetic energy at these resonances tunnels through the narrow waveguide channels with almost no propagation losses. Under the tunneling behavior, high-intensity electromagnetic fields are produced in the vicinity of the metallic wires. These intense field resonances can be exploited to build highly sensitive dielectric sensors. The sensor operation is explained with the help of full-wave simulations. A practical setup consisting of a 3D waveguide bend is presented to experimentally observe the tunneling phenomenon. The tunneling frequency is predicted by determining the input impedance minima through a variational formula based on the Green function of a probe-excited parallel plate waveguide.

  11. Residue contact-count potentials are as effective as residue-residue contact-type potentials for ranking protein decoys

    Directory of Open Access Journals (Sweden)

    Duarte Jose

    2008-12-01

    Full Text Available Abstract Background For over 30 years potentials of mean force have been used to evaluate the relative energy of protein structures. The most commonly used potentials define the energy of residue-residue interactions and are derived from the empirical analysis of the known protein structures. However, single-body residue 'environment' potentials, although widely used in protein structure analysis, have not been rigorously compared to these classical two-body residue-residue interaction potentials. Here we do not try to combine the two different types of residue interaction potential, but rather to assess their independent contribution to scoring protein structures. Results A data set of nearly three thousand monomers was used to compare pairwise residue-residue 'contact-type' propensities to single-body residue 'contact-count' propensities. Using a large and standard set of protein decoys we performed an in-depth comparison of these two types of residue interaction propensities. The scores derived from the contact-type and contact-count propensities were assessed using two different performance metrics and were compared using 90 different definitions of residue-residue contact. Our findings show that both types of score perform equally well on the task of discriminating between near-native protein decoys. However, in a statistical sense, the contact-count based scores were found to carry more information than the contact-type based scores. Conclusion Our analysis has shown that the performance of either type of score is very similar on a range of different decoys. This similarity suggests a common underlying biophysical principle for both types of residue interaction propensity. However, several features of the contact-count based propensity suggests that it should be used in preference to the contact-type based propensity. Specifically, it has been shown that contact-counts can be predicted from sequence information alone. In addition, the use

  12. Scientific Opinion on the safety evaluation of a time-temperature indicator system, based on Carnobacterium maltaromaticum and acid fuchsin for use in food contact materials

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2013-07-01

    Full Text Available This scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety evaluation of a system based on Carnobacterium maltaromaticum and a colour change indicator, acid fuchsin (CAS number 3244-88-0, FCM Substance No 01033, used as a time-temperature indicator on the packaging of chilled food. The micro-organism, the indicator and a nutritive medium gel are incorporated in a multilayer plastic sachet glued onto the outer layer of the food package. All the substances constituting the system, with the exception of acid fuchsin, are authorised as food additives, food colorants or novel food ingredients, or are an enzymatic digest of edible protein sources and yeast edible extract. Specific migration of acid fuchsin was estimated to be less than 7 x 10-9 mg/kg food. Acid fuchsin elicited a positive response in a bacterial gene mutation assay and a negative response in an in vitro micronucleus assay. Given the lack of in vivo studies, the genotoxicity potential of acid fuchsin cannot be ruled out. However, the Panel noted that the layer of the plastic sachet in contact with food contact articles behaves as a barrier which prevents any release of its content (including acid fuchsin, and that the sachet is stuck onto the outer layer of the packaging, hence is not in contact with the food. Thus no exposure to the substances constituting the system from the consumption of the packed food is expected under the intended conditions of use. Therefore, the Panel concluded that the substances of the intelligent system, C. maltaromaticum and acid fuchsin, do not raise a safety concern for the consumer when used in a plastic sachet which prevents any migration from the system into food and which is stuck onto the outer layer of the packaging of chilled food.

  13. The quasi-Gaussian entropy theory : Free energy calculations based on the potential energy distribution function

    NARCIS (Netherlands)

    Amadei, A; Apol, MEF; DiNola, A; Berendsen, HJC

    1996-01-01

    A new theory is presented for calculating the Helmholtz free energy based on the potential energy distribution function. The usual expressions of free energy, internal energy and entropy involving the partition function are rephrased in terms of the potential energy distribution function, which must

  14. Contact Lenses for Vision Correction

    Science.gov (United States)

    ... Ask an Ophthalmologist Español Eye Health / Glasses & Contacts Contact Lenses Sections Contact Lenses for Vision Correction Proper ... to Know About Contact Lenses Colored Contact Lenses Contact Lenses for Vision Correction Written by: Kierstan Boyd ...

  15. Flow based vs. demand based energy-water modelling

    Science.gov (United States)

    Rozos, Evangelos; Nikolopoulos, Dionysis; Efstratiadis, Andreas; Koukouvinos, Antonios; Makropoulos, Christos

    2015-04-01

    The water flow in hydro-power generation systems is often used downstream to cover other type of demands like irrigation and water supply. However, the typical case is that the energy demand (operation of hydro-power plant) and the water demand do not coincide. Furthermore, the water inflow into a reservoir is a stochastic process. Things become more complicated if renewable resources (wind-turbines or photovoltaic panels) are included into the system. For this reason, the assessment and optimization of the operation of hydro-power systems are challenging tasks that require computer modelling. This modelling should not only simulate the water budget of the reservoirs and the energy production/consumption (pumped-storage), but should also take into account the constraints imposed by the natural or artificial water network using a flow routing algorithm. HYDRONOMEAS, for example, uses an elegant mathematical approach (digraph) to calculate the flow in a water network based on: the demands (input timeseries), the water availability (simulated) and the capacity of the transmission components (properties of channels, rivers, pipes, etc.). The input timeseries of demand should be estimated by another model and linked to the corresponding network nodes. A model that could be used to estimate these timeseries is UWOT. UWOT is a bottom up urban water cycle model that simulates the generation, aggregation and routing of water demand signals. In this study, we explore the potentials of UWOT in simulating the operation of complex hydrosystems that include energy generation. The evident advantage of this approach is the use of a single model instead of one for estimation of demands and another for the system simulation. An application of UWOT in a large scale system is attempted in mainland Greece in an area extending over 130×170 km². The challenges, the peculiarities and the advantages of this approach are examined and critically discussed.

  16. Contact fiber bundles

    OpenAIRE

    Lerman, Eugene

    2003-01-01

    We define contact fiber bundles and investigate conditions for the existence of contact structures on the total space of such a bundle. The results are analogous to minimal coupling in symplectic geometry. The two applications are construction of K-contact manifolds generalizing Yamazaki's fiber join construction and a cross-section theorem for contact moment maps

  17. Hydrogen based energy storage for solar energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Vanhanen, J.; Hagstroem, M.; Lund, P. [Helsinki Univ. of Technology, Otaniemi (Finland). Advanced Energy Systems

    1998-10-01

    The main technical constraint in solar energy systems which operate around the year is the lack of suitable long-term energy storage. Conventional solutions to overcome the problem of seasonal storage in PV power systems are to use oversized batteries as a seasonal energy storage, or to use a diesel back-up generator. However, affordable lead-acid batteries are not very suitable for seasonal energy storage because of a high self-discharge rate and enhanced deterioration and divergence of the single cells during prolonged periods of low state of charge in times of low irradiation. These disadvantages can be avoided by a back-up system, e.g. a diesel generator, which car supply energy to the loads and charge the battery to the full state of charge to avoid the above mentioned disadvantages. Unfortunately, diesel generators have several disadvantages, e.g. poor starting reliability, frequent need for maintenance and noise

  18. Zirconia-based dental crown to support a removable partial denture: a three-dimensional finite element analysis using contact elements and micro-CT data.

    Science.gov (United States)

    Rocha, Eduardo Passos; Anchieta, Rodolfo Bruniera; de Almeida, Erika Oliveira; Freitas, Amilcar Chagas; Martini, Ana Paula; Sotto-Maior, Bruno Sales; Luersen, Marco Antonio; Ko, Ching Chang

    2015-01-01

    Veneer fracture is the most common complication in zirconia-based restorations. The aim of this study was to evaluate the mechanical behavior of a zirconia-based crown in a lower canine tooth supporting removable partial denture (RPD) prosthesis, varying the bond quality of the veneer/coping interface. Microtomography (μCT) data of an extracted left lower canine were used to build the finite element model (M) varying the core material (gold core - MAu; zirconia core - MZi) and the quality of the veneer/core interface (complete bonded - MZi; incomplete bonded - MZi-NL). The incomplete bonding condition was only applied for zirconia coping by using contact elements (Target/Contact) with 0.3 frictional coefficients. Stress fields were obtained using Ansys Workbench 10.0. The loading condition (L = 1 N) was vertically applied at the base of the RPD prosthesis metallic support towards the dental apex. Maximum principal (σmax) and von Mises equivalent (σvM) stresses were obtained. The σmax (MPa) for the bonded condition was similar between gold and zirconia cores (MAu, 0.42; MZi, 0.40). The incomplete bonded condition (MZi-NL) raised σmax in the veneer up to 800% (3.23 MPa) in contrast to the bonded condition. The peak of σvM increased up to 270% in the MZi-NL. The incomplete bond condition increasing the stress in the veneer/zirconia interface.

  19. Fabrication of polyimide micro/nano-structures based on contact-transfer and mask-embedded lithography

    Science.gov (United States)

    Chiu, Cheng-Yu; Lee, Yung-Chun

    2009-10-01

    Polyimide materials are well known for their excellent mechanical and chemical stability which, as an adverse consequence, makes their fabrication processes much more difficult, especially in micro- and nano-scales. In this paper, we demonstrate an innovative and powerful method for fabricating micro/nano-structures on polyimides. The proposed method first adopts an imprinting approach to transfer a patterned metal film from a mold to a polymer layer coated on a polyimide layer. The patterned double polymer layers are then dry etched using the transferred metal pattern as an etching mask. Finally, polyimide structures are obtained by lifting off the top polymer layer and the metal film through wet etching. Experiments have been carried out and important parameters to achieve high pattern-transformation fidelity are determined. Fine structures of polyimides with a feature size of 500 nm and a total patterned area of 8 × 8 mm2 are demonstrated. Advantages of the proposed method include low-temperature, low contact pressure, small feature size, high throughput and ease of in implementation. Most importantly, it is applicable for a large number of tough polymers which are difficult to deal with by other methods in terms of micro/nano-fabrication.

  20. Solid-contact potentiometric aptasensor based on aptamer functionalized carbon nanotubes for the direct determination of proteins.

    Science.gov (United States)

    Düzgün, Ali; Maroto, Alicia; Mairal, Teresa; O'Sullivan, Ciara; Rius, F Xavier

    2010-05-01

    A facile, solid-contact selective potentiometric aptasensor exploiting a network of single-walled carbon nanotubes (SWCNT) acting as a transducing element is described in this work. The molecular properties of the SWCNT surface have been modified by covalently linking aptamers as biorecognition elements to the carboxylic groups of the SWCNT walls. As a model system to demonstrate the generic application of the approach, a 15-mer thrombin aptamer interacts with thrombin and the affinity interaction gives rise to a direct potentiometric signal that can be easily recorded within 15 s. The dynamic linear range, with a sensitivity of 8.0 mV/log a(Thr) corresponds to the 10(-7)-10(-6) M range of thrombin concentrations, with a limit of detection of 80 nM. The aptasensor displays selectivity against elastase and bovine serum albumin and is easily regenerated by immersion in 2 M NaCl. The aptasensor demonstrates the capacity of direct detection of the recognition event avoiding the use of labels, mediators, or the addition of further reagents or analyte accumulation. PMID:20419254

  1. Trap-Assisted Transport and Non-Uniform Charge Distribution in Sulfur-Rich PbS Colloidal Quantum Dot-based Solar Cells with Selective Contacts.

    Science.gov (United States)

    Malgras, Victor; Zhang, Guanran; Nattestad, Andrew; Clarke, Tracey M; Mozer, Attila J; Yamauchi, Yusuke; Kim, Jung Ho

    2015-12-01

    This study reports evidence of dispersive transport in planar PbS colloidal quantum dot heterojunction-based devices as well as the effect of incorporating a MoO3 hole selective layer on the charge extraction behavior. Steady state and transient characterization techniques are employed to determine the complex recombination processes involved in such devices. The addition of a selective contact drastically improves the device efficiency up to 3.15% (especially due to increased photocurrent and decreased series resistance) and extends the overall charge lifetime by suppressing the main first-order recombination pathway observed in device without MoO3. The lifetime and mobility calculated for our sulfur-rich PbS-based devices are similar to previously reported values in lead-rich quantum dots-based solar cells. Nevertheless, strong Shockley-Read-Hall mechanisms appear to keep restricting charge transport, as the equilibrium voltage takes more than 1 ms to be established. PMID:26541422

  2. Dynamics of social contagions with limited contact capacity

    Science.gov (United States)

    Wang, Wei; Shu, Panpan; Zhu, Yu-Xiao; Tang, Ming; Zhang, Yi-Cheng

    2015-10-01

    Individuals are always limited by some inelastic resources, such as time and energy, which restrict them to dedicate to social interaction and limit their contact capacities. Contact capacity plays an important role in dynamics of social contagions, which so far has eluded theoretical analysis. In this paper, we first propose a non-Markovian model to understand the effects of contact capacity on social contagions, in which each adopted individual can only contact and transmit the information to a finite number of neighbors. We then develop a heterogeneous edge-based compartmental theory for this model, and a remarkable agreement with simulations is obtained. Through theory and simulations, we find that enlarging the contact capacity makes the network more fragile to behavior spreading. Interestingly, we find that both the continuous and discontinuous dependence of the final adoption size on the information transmission probability can arise. There is a crossover phenomenon between the two types of dependence. More specifically, the crossover phenomenon can be induced by enlarging the contact capacity only when the degree exponent is above a critical degree exponent, while the final behavior adoption size always grows continuously for any contact capacity when degree exponent is below the critical degree exponent.

  3. Dynamics of social contagions with limited contact capacity.

    Science.gov (United States)

    Wang, Wei; Shu, Panpan; Zhu, Yu-Xiao; Tang, Ming; Zhang, Yi-Cheng

    2015-10-01

    Individuals are always limited by some inelastic resources, such as time and energy, which restrict them to dedicate to social interaction and limit their contact capacities. Contact capacity plays an important role in dynamics of social contagions, which so far has eluded theoretical analysis. In this paper, we first propose a non-Markovian model to understand the effects of contact capacity on social contagions, in which each adopted individual can only contact and transmit the information to a finite number of neighbors. We then develop a heterogeneous edge-based compartmental theory for this model, and a remarkable agreement with simulations is obtained. Through theory and simulations, we find that enlarging the contact capacity makes the network more fragile to behavior spreading. Interestingly, we find that both the continuous and discontinuous dependence of the final adoption size on the information transmission probability can arise. There is a crossover phenomenon between the two types of dependence. More specifically, the crossover phenomenon can be induced by enlarging the contact capacity only when the degree exponent is above a critical degree exponent, while the final behavior adoption size always grows continuously for any contact capacity when degree exponent is below the critical degree exponent. PMID:26520068

  4. Non-contact video-based vital sign monitoring using ambient light and auto-regressive models.

    Science.gov (United States)

    Tarassenko, L; Villarroel, M; Guazzi, A; Jorge, J; Clifton, D A; Pugh, C

    2014-05-01

    Remote sensing of the reflectance photoplethysmogram using a video camera typically positioned 1 m away from the patient's face is a promising method for monitoring the vital signs of patients without attaching any electrodes or sensors to them. Most of the papers in the literature on non-contact vital sign monitoring report results on human volunteers in controlled environments. We have been able to obtain estimates of heart rate and respiratory rate and preliminary results on changes in oxygen saturation from double-monitored patients undergoing haemodialysis in the Oxford Kidney Unit. To achieve this, we have devised a novel method of cancelling out aliased frequency components caused by artificial light flicker, using auto-regressive (AR) modelling and pole cancellation. Secondly, we have been able to construct accurate maps of the spatial distribution of heart rate and respiratory rate information from the coefficients of the AR model. In stable sections with minimal patient motion, the mean absolute error between the camera-derived estimate of heart rate and the reference value from a pulse oximeter is similar to the mean absolute error between two pulse oximeter measurements at different sites (finger and earlobe). The activities of daily living affect the respiratory rate, but the camera-derived estimates of this parameter are at least as accurate as those derived from a thoracic expansion sensor (chest belt). During a period of obstructive sleep apnoea, we tracked changes in oxygen saturation using the ratio of normalized reflectance changes in two colour channels (red and blue), but this required calibration against the reference data from a pulse oximeter. PMID:24681430

  5. Non-contact video-based vital sign monitoring using ambient light and auto-regressive models

    International Nuclear Information System (INIS)

    Remote sensing of the reflectance photoplethysmogram using a video camera typically positioned 1 m away from the patient’s face is a promising method for monitoring the vital signs of patients without attaching any electrodes or sensors to them. Most of the papers in the literature on non-contact vital sign monitoring report results on human volunteers in controlled environments. We have been able to obtain estimates of heart rate and respiratory rate and preliminary results on changes in oxygen saturation from double-monitored patients undergoing haemodialysis in the Oxford Kidney Unit. To achieve this, we have devised a novel method of cancelling out aliased frequency components caused by artificial light flicker, using auto-regressive (AR) modelling and pole cancellation. Secondly, we have been able to construct accurate maps of the spatial distribution of heart rate and respiratory rate information from the coefficients of the AR model. In stable sections with minimal patient motion, the mean absolute error between the camera-derived estimate of heart rate and the reference value from a pulse oximeter is similar to the mean absolute error between two pulse oximeter measurements at different sites (finger and earlobe). The activities of daily living affect the respiratory rate, but the camera-derived estimates of this parameter are at least as accurate as those derived from a thoracic expansion sensor (chest belt). During a period of obstructive sleep apnoea, we tracked changes in oxygen saturation using the ratio of normalized reflectance changes in two colour channels (red and blue), but this required calibration against the reference data from a pulse oximeter. (paper)

  6. MEMS-based contact stress field measurements at a rough elastomeric layer: local test of Amontons’ friction law in static and steady sliding regimes

    Directory of Open Access Journals (Sweden)

    Debrégeas G.

    2010-06-01

    Full Text Available We present the results of recent friction experiments in which a MEMS-based sensing device is used to measure both the normal and tangential stress fields at the base of a rough elastomer film in frictional contact with smooth, rigid, glass indentors. We consider successively multicontacts under (i static normal loading by a spherical indentor and (ii frictional steady sliding conditions against a cylindrical indentor, for an increasing normal load. In both cases, the measured fields are compared to elastic calculations assuming (i a smooth interface and (ii Amontons’ friction law. In the static case, significant deviations are observed which decrease with increasing load and which vanish when a lubricant is used. In the steady sliding case, Amontons’ law reproduces rather satisfactorily the experiments provided that the normal/tangential coupling at the contact interface is taken into account. We discuss the origin of the difference between the Amontons fields and the measured ones, in particular the effect of the finite normal and tangential compliances of the multicontact interface.

  7. Automated bone removal in CT angiography: Comparison of methods based on single energy and dual energy scans

    Energy Technology Data Exchange (ETDEWEB)

    Straten, Marcel van; Schaap, Michiel; Dijkshoorn, Marcel L.; Greuter, Marcel J.; Lugt, Aad van der; Krestin, Gabriel P.; Niessen, Wiro J. [Department of Radiology, Erasmus MC University Medical Center, P.O. Box 2040, 3000 CA Rotterdam (Netherlands); Departments of Radiology and Medical Informatics, Erasmus MC University Medical Center, P.O. Box 2040, 3000 CA Rotterdam (Netherlands); Department of Radiology, Erasmus MC University Medical Center, P.O. Box 2040, 3000 CA Rotterdam (Netherlands); Department of Radiology, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB Groningen (Netherlands); Department of Radiology, Erasmus MC University Medical Center, P.O. Box 2040, 3000 CA Rotterdam (Netherlands); Departments of Radiology and Medical Informatics, Erasmus MC University Medical Center, P.O. Box 2040, 3000 CA Rotterdam (Netherlands)

    2011-11-15

    Purpose: To evaluate dual energy based methods for bone removal in computed tomography angiography (CTA) images and compare these with single energy based methods that use an additional, nonenhanced, CT scan. Methods: Four different bone removal methods were applied to CT scans of an anthropomorphic thorax phantom, acquired with a second generation dual source CT scanner. The methods differed by the way information on the presence of bone was obtained (either by using an additional, nonenhanced scan or by scanning with two tube voltages at the same time) and by the way the bone was removed from the CTA images (either by masking or subtracting the bone). The phantom contained parts which mimic vessels of various diameters in direct contact with bone. Both a quantitative and qualitative analysis of image quality after bone removal was performed. Image quality was quantified by the contrast-to-noise ratio (CNR) normalized to the square root of the dose (CNRD). At locations where vessels touch bone, the quality of the bone removal and the vessel preservation were visually assessed. The dual energy based methods were assessed with and without the addition of a 0.4 mm tin filter to the high voltage x-ray tube filtration. For each bone removal method, the dose required to obtain a certain CNR after bone removal was compared with the dose of a reference scan with the same CNR but without automated bone removal. The CNRD value of the reference scan was maximized by choosing the lowest tube voltage available. Results: All methods removed the bone completely. CNRD values were higher for the masking based methods than for the subtraction based methods. Single energy based methods had a higher CNRD value than the corresponding dual energy based methods. For the subtraction based dual energy method, tin filtration improved the CNRD value with approximately 50%. For the masking based dual energy method, it was easier to differentiate between iodine and bone when tin filtration

  8. Contact force models for multibody dynamics

    CERN Document Server

    Flores, Paulo

    2016-01-01

    This book analyzes several compliant contact force models within the context of multibody dynamics, while also revisiting the main issues associated with fundamental contact mechanics. In particular, it presents various contact force models, from linear to nonlinear, from purely elastic to dissipative, and describes their parameters. Addressing the different numerical methods and algorithms for contact problems in multibody systems, the book describes the gross motion of multibody systems by using a two-dimensional formulation based on the absolute coordinates and employs different contact models to represent contact-impact events. Results for selected planar multibody mechanical systems are presented and utilized to discuss the main assumptions and procedures adopted throughout this work. The material provided here indicates that the prediction of the dynamic behavior of mechanical systems involving contact-impact strongly depends on the choice of contact force model. In short, the book provides a comprehens...

  9. A Web Based Puzzle for Energy Sources

    Directory of Open Access Journals (Sweden)

    Nilgun SECKEN

    2006-07-01

    Full Text Available At present many countries in the world consume too much fossil fuels such as petroleum, natural gas and coal to meet their energy needs. These fossil fuels are not renewable; their sources are limited and reducing gradually. More importantly they have been becoming more expensive day by day and their damage to the environment has been increasing. In spite of it, renewable energy sources are renewed and never run out. In addition there are many benefits of renewable energy. In this study a puzzle is prepared for primary-school students aiming at teaching of energy sources as a supplementary source. In the mean time, the puzzle we prepared reveals the advantages and disadvantages of renewable and fossil energy sources. Here, the student’s aim is to complete the puzzle by answering the questions respectively. .

  10. Web-Based Treatment Program Using Intensive Therapeutic Contact for Patients With Eating Disorders: Before-After Study

    NARCIS (Netherlands)

    Huurne, ter E.D.; Postel, M.G.; Haan, de H.A.; Drossaert, C.H.C.; Jong, C.A.J.

    2013-01-01

    Background: Although eating disorders are common in the Netherlands, only a few patients are treated by mental health care professionals. To reach and treat more patients with eating disorders, Tactus Addiction Treatment developed a web-based treatment program with asynchronous and intensive persona

  11. Scientific Opinion on the safety assessment of the process SOREPET GR based on EREMA Basic technology used to recycle post-consumer PET into food contact materials

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2014-04-01

    Full Text Available This scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety assessment of the recycling process SOREPET GR (EU register No RECYC073 which is based on the EREMA Basic technology. The input to the process is hot caustic washed and dried poly(ethylene terephthalate (PET flakes originating from collected post-consumer PET containers, mainly bottles and containing no more than 5 % PET from non-food consumer applications. In this process, washed and dried PET flakes are heated in a continuous reactor under vacuum before being extruded. Having examined the results of the challenge test provided, the Panel concluded that the continuous reactor is the critical step that determines the decontamination efficiency of the process. The operating parameters to control its performance are well defined and are temperature, pressure and residence time. Under these conditions, it was demonstrated that the recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the modelled migration of 0.1 μg/kg food derived from the exposure scenario for infants and 0.15 μg/kg food derived from the exposure scenario for toddlers. The Panel concluded that recycled PET obtained from the process is not of safety concern when used to manufacture articles intended for food contact materials applications in compliance with the conditions as specified in the conclusion of the opinion.

  12. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... like a suction cup." Halloween is a popular time for people to use colored contact lenses to ... wear costume contact lenses for Halloween or any time of year, follow these guidelines: Get an eye ...

  13. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... popping touch. But colored contact lenses are popular year-round, not just at Halloween. But few know ... contact lenses for Halloween or any time of year, follow these guidelines: Get an eye exam from ...

  14. Irritant Contact Dermatitis

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Irritant Contact Dermatitis Information for adults A A A This image ... scaling bumps and slightly elevated lesions typical of dermatitis, with severe involvement in the patient's armpit. Overview ...

  15. Interfacial closure of contacting surfaces

    Science.gov (United States)

    Rieutord, F.; Rauer, C.; Moriceau, H.

    2014-08-01

    Understanding the contact between solid surfaces is a long-standing problem which has a strong impact on the physics of many processes such as adhesion, friction, lubrication and wear. Experimentally, the investigation of solid/solid interfaces remains challenging today, due to the lack of experimental techniques able to provide sub-nanometer scale information on interfaces buried between millimeters of materials. Yet, a strong interest exists improving the modeling of contact mechanics of materials in order to adjust their interface properties (e.g., thermal transport, friction). We show here that the essential features of the residual gap between contacting surfaces can be measured using high energy X-ray synchrotron reflectivity. The presence of this nano-gap is general to the contact of solids. In some special case however, it can be removed when attractive forces take over repulsive contributions, depending on both height and wavelength of asperity distributions (roughness). A criterion for this instability is established in the standard case of van der Waals attractive forces and elastic asperity compression repulsive forces (Hertz model). This collapse instability is confirmed experimentally in the case of silicon direct bonding, using high-energy X-ray synchrotron reflectivity and adhesion energy measurements. The possibility to achieve fully closed interfaces at room temperature opens interesting perspectives to build stronger assemblies with smaller thermal budgets.

  16. A Web Based Puzzle for Energy Sources

    OpenAIRE

    Nilgun SECKEN

    2006-01-01

    At present many countries in the world consume too much fossil fuels such as petroleum, natural gas and coal to meet their energy needs. These fossil fuels are not renewable; their sources are limited and reducing gradually. More importantly they have been becoming more expensive day by day and their damage to the environment has been increasing. In spite of it, renewable energy sources are renewed and never run out. In addition there are many benefits of renewable energy. In this study a puz...

  17. Energy concepts for self-supplying communities based on local and renewable energy sources

    DEFF Research Database (Denmark)

    Petersen, Jens-Phillip

    2016-01-01

    , as responsible entities for physical planning, can hold a key role in transforming energy systems towards carbon-neutrality, based on renewable energies. The implementation should be approached at community scale, which has advantages compared to only focusing on buildings or cities. But community energy...... settings. The current case study presents a community energy concept for the inner-city of Elmshorn. By estimating the energy demand, consideration of local energy saving potentials, and available energy potentials within the community, it was possible to develop several energy system variants...... that virtually allow a heating energy and electricity supply fully based on local, renewable energy resources. The most feasible and cost-efficient variant is the use of local food production waste in a CHP plant feeding a district heating grid. The overall aim is to show that a self-sufficient heat...

  18. Contact-free and pose-invariant hand-biometric-based personal identification system using RGB and depth data

    Institute of Scientific and Technical Information of China (English)

    Can WANG; Hong LIU; Xing LIU

    2014-01-01

    Hand-biometric-based personal identifi cation is considered to be an effective method for automatic recognition. However, existing systems require strict constraints during data acquisition, such as costly devices, specifi ed postures, simple background, and stable illumination. In this paper, a contactless personal identifi cation system is proposed based on matching hand geometry features and color features. An inexpensive Kinect sensor is used to acquire depth and color images of the hand. During image acquisition, no pegs or surfaces are used to constrain hand position or posture. We segment the hand from the background through depth images through a process which is insensitive to illumination and background. Then fi nger orientations and landmark points, like fi nger tips or fi nger valleys, are obtained by geodesic hand contour analysis. Geometric features are extracted from depth images and palmprint features from intensity images. In previous systems, hand features like fi nger length and width are normalized, which results in the loss of the original geometric features. In our system, we transform 2D image points into real world coordinates, so that the geometric features remain invariant to distance and perspective effects. Extensive experiments demonstrate that the proposed hand-biometric-based personal identifi cation system is effective and robust in various practical situations.

  19. Mixed lubricated line contacts

    NARCIS (Netherlands)

    Faraon, Irinel Cosmin

    2005-01-01

    The present work deals with friction in mixed lubricated line contacts. Components in systems are becoming smaller and due to, for instance power transmitted, partial contact may occur. In industrial applications, friction between the moving contacting surfaces cannot be avoided, therefore it is ess

  20. New Cosmetic Contact Allergens

    Directory of Open Access Journals (Sweden)

    An Goossens

    2015-02-01

    Full Text Available Allergic and photo-allergic contact dermatitis, and immunologic contact urticaria are potential immune-mediated adverse effects from cosmetics. Fragrance components and preservatives are certainly the most frequently observed allergens; however, all ingredients must be considered when investigating for contact allergy.

  1. Energy Based Acoustic Measurement Senors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This research focuses on fully developing energy density sensors that will yield a significant benefit both for measurements of interest to NASA, as well as for...

  2. Hydrogen based global renewable energy network

    Energy Technology Data Exchange (ETDEWEB)

    Akai, Makoto [Mechanical Engineering Laboratory, AIST, MITI, Namiki, Tsukuba (Japan)

    1993-12-31

    In the last quarter of this century, global environmental problem has emerged as a major scientific, political and social issue. Specific Problems include: depletion of ozone layer by chlorofluorocarbons (CFCs), acid rain, destruction of tropical forests and desertification, pollution of the sea and global wanning due to the greenhouse effect by carbon dioxide and others. Among these problems, particular attention of the world has been focused on the global warming because it has direct linkage to energy consumption which our economic development depends on so far. On the other hand, the future program of The Sunshine Project for alternative energy technology R&D, The Moonlight Project for energy conservation technology R&D, and The Global Environmental Technology Program for environmental problem mitigating technology R&D which are Japan`s national projects being promoted by their Agency of Industrial Science and Technology (AIST) in the Ministry of International Trade and Industry have been reexamined in view of recent changes in the situations surrounding new energy technology. In this regard, The New Sunshine Program will be established by integrating these three activities to accelerate R&D in the field of energy and environmental technologies. In the reexamination, additional stress has been laid on the contribution to solving global environmental problem through development of clean renewable energies which constitute a major part of the {open_quotes}New Earth 21{close_quotes}, a comprehensive, long-term and international cooperative program proposed by MITI. The present paper discusses the results of feasibility study on hydrogen energy system leading to the concept of WE-NET following a brief summary on R&D status on solar and wind energy in Japan.

  3. An agent-based model for energy service companies

    International Nuclear Information System (INIS)

    Highlights: • An agent-based model for household energy efficiency upgrades is considered. • Energy service companies provide an alternative to traditional utility providers. • Household self-financing is a limiting factor to widespread efficiency upgrading. • Longer term service contracts can lead to reduced household energy costs. • Future energy price increases enable service providers to retain their customer base. - Abstract: The residential housing sector is a major consumer of energy accounting for approximately one third of carbon emissions in the United Kingdom. Achieving a sustainable, low-carbon infrastructure necessitates a reduced and more efficient use of domestic energy supplies. Energy service companies offer an alternative to traditional providers, which supply a single utility product to satisfy the unconstrained demand of end users, and have been identified as a potentially important actor in sustainable future economies. An agent-based model is developed to examine the potential of energy service companies to contribute to the large scale upgrading of household energy efficiency, which would ultimately lead to a more sustainable and secure energy infrastructure. The migration of households towards energy service companies is described by an attractiveness array, through which potential customers can evaluate the future benefits, in terms of household energy costs, of changing provider. It is shown that self-financing is a limiting factor to the widespread upgrading of residential energy efficiency. Greater reductions in household energy costs could be achieved by committing to longer term contracts, allowing upgrade costs to be distributed over greater time intervals. A steadily increasing cost of future energy usage lends an element of stability to the market, with energy service companies displaying the ability to retain customers on contract expiration. The model highlights how a greater focus on the provision of energy services, as

  4. Carbon nanotube-based hybrid hole-transporting material and selective contact for high efficiency perovskite solar cells

    OpenAIRE

    Aitola, Kerttu; Sveinbjörnsson, Kári; Correa-Baena, Juan-Pablo; Kaskela, Antti; Abate, Antonio; Tian, Ying; Johansson, Erik M. J.; Graetzel, Michael; Kauppinen, Esko I.; Hagfeldt, Anders; Boschloo, Gerrit

    2016-01-01

    We demonstrate a high efficiency perovskite solar cell with a hybrid hole-transporting material-counter electrode based on a thin single-walled carbon nanotube (SWCNT) film and a drop-cast 2,2,7,-7-tetrakis(N, N-di-p-methoxyphenylamine)-9,90-spirobifluorene (Spiro-OMeTAD) hole-transporting material (HTM). The average efficiency of the solar cells was 13.6%, with the record cell yielding 15.5% efficiency. The efficiency of the reference solar cells with spin-coated Spiro-OMeTAD hole-transporti...

  5. CALCULATION OF CONTACT STRESS OF PLASTIC GEARS

    Institute of Scientific and Technical Information of China (English)

    陈其泰

    1995-01-01

    A calculation method of contact problem of plastic gears based on three parameter model of viscoelasticity material is presented. In this calculation method, the influence of temperature upon the property of plastics is considered and an iteration process of temperature-elasticity module-friction coefficient is proposed. From the rolling contact problem of two viscoelastic cylinders with parallel axis, a set of normal-tangential contact coupled integral equations is obtained. Through numerical treatment and normal-tangental iteration, the normal contact stress, tangential stress and contact width of plastic gears are acquired.

  6. Semi-insulating GaAs-based Schottky contacts in the role of detectors of ionising radiation: An effect of the interface treatment

    CERN Document Server

    Ivanco, J; Darmo, J; Krempasky, M; Besse, I; Senderak, R

    1999-01-01

    It is generally agreed that the substrate material quality plays a key role in the performance of back-to-back detectors of ionising radiation based on semi-insulating (SI) material. The aim of this paper is to evaluate usually overlooked problem, namely the influence of the Schottky contact preparation on detector performance. We report on different approaches to modify and control the quality of the metal/SI GaAs interface via a treatment of the SI-GaAs surface by means of low-temperature hydrogen plasma and wet etching. The measured electrical and detecting properties of such structures display a strong dependence on the history and the way the GaAs surface is treated prior to the metal evaporation. We point out, therefore, that the semiconductor surface treatment before the Schottky metallization plays a role of comparable importance to the influence of the SI-GaAs substrate properties on detector performances. (author)

  7. Kinetic energy decomposition scheme based on information theory.

    Science.gov (United States)

    Imamura, Yutaka; Suzuki, Jun; Nakai, Hiromi

    2013-12-15

    We proposed a novel kinetic energy decomposition analysis based on information theory. Since the Hirshfeld partitioning for electron densities can be formulated in terms of Kullback-Leibler information deficiency in information theory, a similar partitioning for kinetic energy densities was newly proposed. The numerical assessments confirm that the current kinetic energy decomposition scheme provides reasonable chemical pictures for ionic and covalent molecules, and can also estimate atomic energies using a correction with viral ratios.

  8. Contact lens in keratoconus

    Directory of Open Access Journals (Sweden)

    Varsha M Rathi

    2013-01-01

    Full Text Available Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP lenses, soft and soft toric lenses, piggy back contact lenses (PBCL, hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL.

  9. Market-Based Mechanisms to Promote Renewable Energy in Asia

    OpenAIRE

    Venkatachalam ANBUMOZHI; Alex BOWEN; Puthusserikunnel Devasia JOSE

    2015-01-01

    Market-based instruments such as Renewable Energy Certificate (REC) are increasingly favoured as an alternative to command-and-control legislation to increase the uptake of renewable energy. Focusing on the renewable energy industry and policy situation in Asia, this paper analysed the strengths and weaknesses of market-based approaches in the long-term interest of developing Asia. It found that approaches such as REC are disadvantaged by a lack of both market acceptance and a strong institut...

  10. Smart and Green Energy (SAGE) for Base Camps Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Engels, Matthias; Boyd, Paul A.; Koehler, Theresa M.; Goel, Supriya; Sisk, Daniel R.; Hatley, Darrel D.; Mendon, Vrushali V.; Hail, John C.

    2014-02-11

    The U.S. Army Logistics Innovation Agency’s (LIA’s) Smart and Green Energy (SAGE) for Base Camps project was to investigate how base camps’ fuel consumption can be reduced by 30% to 60% using commercial off-the-shelf (COTS) technologies for power generation, renewables, and energy efficient building systems. Field tests and calibrated energy models successfully demonstrated that the fuel reductions are achievable.

  11. The Effect of Electrode Designs Based on the Anatomical Heart Location for the Non-Contact Heart Activity Measurement.

    Science.gov (United States)

    Gi, Sun Ok; Lee, Young-Jae; Koo, Hye Ran; Lee, Seung Pyo; Lee, Kang-Hwi; Kim, Kyeng-Nam; Kang, Seung-Jin; Lee, Joo Hyeon; Lee, Jeong-Whan

    2015-12-01

    This research is an extension of a previous research [1] on the different effects of sensor location that is relatively suitable for heart rate sensing. This research aimed to elucidate the causes of wide variations in heart rate measurements from the same sensor position among subjects, as observed in previous research [1], and to enhance designs of the inductive textile electrode to overcome these variations. To achieve this, this study comprised two parts: In part 1, X-ray examinations were performed to determine the cause of the wide variations noted in the findings from previous research [1], and we found that at the same sensor position, the heart activity signal differed with slight differences in the positions of the heart of each subject owing to individual differences in the anatomical heart location. In part 2, three types of dual-loop-type textile electrodes were devised to overcome variations in heart location that were confirmed in part 1 of the study. The variations with three types of sensor designs were compared with that with a single-round type of electrode design, by using computer simulation and by performing a t-test on the data obtained from the experiments. We found that the oval-oval shaped, dual-loop-type textile electrode was more suitable than the single round type for determining morphological characteristics as well as for measuring appropriate heart activity signals. Based on these results, the oval-oval, dual-loop-type was a better inductive textile electrode that more effectively overcomes individual differences in heart location during heart activity sensing based on the magnetic-induced conductivity principle. PMID:26490149

  12. The Effect of Electrode Designs Based on the Anatomical Heart Location for the Non-Contact Heart Activity Measurement.

    Science.gov (United States)

    Gi, Sun Ok; Lee, Young-Jae; Koo, Hye Ran; Lee, Seung Pyo; Lee, Kang-Hwi; Kim, Kyeng-Nam; Kang, Seung-Jin; Lee, Joo Hyeon; Lee, Jeong-Whan

    2015-12-01

    This research is an extension of a previous research [1] on the different effects of sensor location that is relatively suitable for heart rate sensing. This research aimed to elucidate the causes of wide variations in heart rate measurements from the same sensor position among subjects, as observed in previous research [1], and to enhance designs of the inductive textile electrode to overcome these variations. To achieve this, this study comprised two parts: In part 1, X-ray examinations were performed to determine the cause of the wide variations noted in the findings from previous research [1], and we found that at the same sensor position, the heart activity signal differed with slight differences in the positions of the heart of each subject owing to individual differences in the anatomical heart location. In part 2, three types of dual-loop-type textile electrodes were devised to overcome variations in heart location that were confirmed in part 1 of the study. The variations with three types of sensor designs were compared with that with a single-round type of electrode design, by using computer simulation and by performing a t-test on the data obtained from the experiments. We found that the oval-oval shaped, dual-loop-type textile electrode was more suitable than the single round type for determining morphological characteristics as well as for measuring appropriate heart activity signals. Based on these results, the oval-oval, dual-loop-type was a better inductive textile electrode that more effectively overcomes individual differences in heart location during heart activity sensing based on the magnetic-induced conductivity principle.

  13. Promoting Behavior-Based Energy Efficiency in Military Housing

    Energy Technology Data Exchange (ETDEWEB)

    AH McMakin; EL Malone; RE Lundgren

    1999-09-07

    The U.S. Department of Energy's Federal Energy Management Program (FEMP) helps agencies reduce the cost of doing business through energy efficiency, water conservation, and the use of solar and other renewable energy. As a large energy user, the U.S. military has been one of the government sectors of focus. Several military installations have shown substantial energy savings in past years. Most of these efficiency projects, however, have focused primarily on physical upgrades, technologies, and purchasing habits. Furthermost projects have focused on administrative and operational areas of energy use. Military residential housing, in particular, has received little formal attention for energy efficiency involving behaviors of the residents themselves. Behavior-based change is a challenging, but potentially fruitful area for energy conservation programs. However, behavioral change involves links with values, social networks and organizations, and new ways of thinking about living patterns. This handbook attempts to fill a gap by offering guidance for promoting such efforts.

  14. Management of Service Brand Contact Point based on Customer Experience%基于顾客体验的服务品牌接触点管理

    Institute of Scientific and Technical Information of China (English)

    罗选荣; 韩顺平

    2013-01-01

      品牌一直是营销研究领域关注的重点内容。而在现有的研究中,对于服务品牌的研究还远远不够。在顾客接受服务的过程中,顾客可能通过接触不同的人员或者服务体验,从而形成不同的服务品牌评价。这种服务品牌的感知和体验对于顾客的口碑和品牌传播具有深远的影响。本文旨在探究不同服务接触点对顾客服务品牌评价的影响,丰富和补充现有文献中对服务品牌的研究。以扎根理论为主导工具,通过收集分析顾客对经济型连锁酒店的网上评论帖子,构建了基于顾客体验的服务品牌接触点模型,探讨了影响顾客体验从而最后影响服务品牌的接触点。研究发现服务质量、服务价格、服务设施和周边情况四个品牌接触点会影响到顾客体验,从而最终影响到顾客的品牌评价。当然,文章也存在一些局限,扎根理论的研究方法在管理学营销学中的应用还不够成熟,本文的研究对象和样本数据的代表性也有些欠缺。%  Brand has always been the focus of marketing research. In the existing research, however, investigations of the service brand are not enough. In the process of receiving services, customers can contact with different service stuffs or service ex-perience, thus to form different evaluation of service brand. This perception and experience of service brand has a profound effect on customers' word-of-mouth and brand communication. This article aims to explore the effect of different contact point on cus-tomers' evaluation of service brand, enrich and supplement the existing literature on service brand. Applying Grounded Theory ap-proach and analyzing the online comments for budget hotels, this paper constructs a contact point model of service brand based on customer experience, to investigate the contact points which affect the customer experience and finally influence the service brand. The study

  15. Direct measurement of graphene contact resistivity to pre-deposited metal in buried contact test structure

    KAUST Repository

    Qaisi, Ramy M.

    2013-08-01

    We demonstrate a buried contact based novel test structure for direct contact resistivity measurement of graphene-metal interfaces. We also observe excellent contact resistivity 1 μO-cm2 without any additional surface modification suggesting that the intrinsic Au-graphene contact is sufficient for achieving devices with low contact resistance. The chemical mechanical polishing less test structure and data described herein highlights an ideal methodology for systematic screening and engineering of graphene-metal contact resistivity to enable low power high speed carbon electronics. © 2013 IEEE.

  16. Landfill energy complex based on the renewable energy installations

    Science.gov (United States)

    Gilmanshin, Iskander; Kashapov, Nail; Gilmanshina, Suriya; Galeeva, Asiya

    2016-06-01

    The article presents the analysis of standard approaches to degassing of landfills. The need of comprehensive work on the degassing of the landfill body is identified. The author's task decomposition of the landfill degassing is formulated. The analysis of existing methods of work on degassing of landfills is presented. The author's approach is including implements of series of parallel studies in the framework of achieving a common goal to reduce the anthropogenic pressure on the ecosystem of the region due to the need for disposal of solid waste. An action plan for the development of the target problem-oriented management techniques of the landfill with the following development of the effective energy complex is formulated.

  17. Electromagnetic ferrofluid-based energy harvester

    Science.gov (United States)

    Bibo, A.; Masana, R.; King, A.; Li, G.; Daqaq, M. F.

    2012-06-01

    This Letter investigates the use of ferrofluids for vibratory energy harvesting. In particular, an electromagnetic micro-power generator which utilizes the sloshing of a ferrofluid column in a seismically-excited tank is proposed to transform mechanical motions directly into electricity. Unlike traditional electromagnetic generators that implement a solid magnet, ferrofluids can easily conform to different shapes and respond to very small acceleration levels offering an untapped opportunity to design scalable energy harvesters. The feasibility of the proposed concept is demonstrated and its efficacy is discussed through several experimental studies.

  18. Development of MEMS based pyroelectric thermal energy harvesters

    Science.gov (United States)

    Hunter, Scott R.; Lavrik, Nickolay V.; Bannuru, Thirumalesh; Mostafa, Salwa; Rajic, Slo; Datskos, Panos G.

    2011-06-01

    The efficient conversion of waste thermal energy into electrical energy is of considerable interest due to the huge sources of low-grade thermal energy available in technologically advanced societies. Our group at the Oak Ridge National Laboratory (ORNL) is developing a new type of high efficiency thermal waste heat energy converter that can be used to actively cool electronic devices, concentrated photovoltaic solar cells, computers and large waste heat producing systems, while generating electricity that can be used to power remote monitoring sensor systems, or recycled to provide electrical power. The energy harvester is a temperature cycled pyroelectric thermal-to-electrical energy harvester that can be used to generate electrical energy from thermal waste streams with temperature gradients of only a few degrees. The approach uses a resonantly driven pyroelectric capacitive bimorph cantilever structure that potentially has energy conversion efficiencies several times those of any previously demonstrated pyroelectric or thermoelectric thermal energy harvesters. The goals of this effort are to demonstrate the feasibility of fabricating high conversion efficiency MEMS based pyroelectric energy converters that can be fabricated into scalable arrays using well known microscale fabrication techniques and materials. These fabrication efforts are supported by detailed modeling studies of the pyroelectric energy converter structures to demonstrate the energy conversion efficiencies and electrical energy generation capabilities of these energy converters. This paper reports on the modeling, fabrication and testing of test structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal-to-electrical energy harvesters.

  19. Biofilm formation by Staphylococcus aureus from food contact surfaces in a meat-based broth and sensitivity to sanitizers

    Directory of Open Access Journals (Sweden)

    Evandro Leite de Souza

    2014-01-01

    Full Text Available This study assessed the capacity of adhesion, the detachment kinetic and the biofilm formation by Staphylococcus aureus isolated from food services on stainless steel and polypropylene surfaces (2 x 2 cm when cultivated in a meat-based broth at 28 and 7 ºC. It was also to study the efficacy of the sanitizers sodium hypochlorite (250 mg/L and peracetic acid (30 mg/L in inactivating the bacterial cells in the preformed biofilm. S. aureus strains adhered in high numbers regardless the assayed surface kind and incubation temperature over 72 h. Cells detachment of surfaces revealed high persistence over the incubation period. Number of cells needed for biofilm formation was noted at all experimental systems already after 3 days. Peracetic acid and sodium hypochlorite were not efficient in completely removing the cells of S. aureus adhered on polypropylene and stainless steel surfaces. From these results, the assayed strains revealed high capacity to adhere and form biofilm on polypropylene and stainless steel surfaces under different growth conditions. Moreover, the cells in biofilm matrix were resistant for total removal when submitted to the exposure to sanitizers.

  20. Energy Performance of Water-based and Air-based Cooling Systems in Plus-energy Housing

    DEFF Research Database (Denmark)

    Andersen, Mads E.; Schøtt, Jacob; Kazanci, Ongun Berk;

    2016-01-01

    -space, and air-to-water heat pump vs. ground heat exchanger as cooling source) on the system energy performance were investigated while achieving the same thermal indoor conditions. The results show that the water-based floor cooling system performed better than the air-based cooling system in terms of energy......Energy use in buildings accounts for a large part of the energy use globally and as a result of this, international building energy performance directives are becoming stricter. This trend has led to the development of zero-energy and plus-energy buildings. Some of these developments have led...... to certain issues regarding thermal indoor environments, such as overheating. Thermal comfort of occupants should not be sacrificed for energy efficiency but rather, these should be achieved simultaneously. Although the priority should be to minimize the cooling demand during the design, this is not always...

  1. Hospital contacts for injuries and musculoskeletal diseases among seamen and fishermen: A population-based cohort study

    Directory of Open Access Journals (Sweden)

    Olsen Jørn

    2008-01-01

    Full Text Available Abstract Background We studied musculoskeletal diseases (MSD and injuries among fishermen and seamen with focus on low back disorders, carpal tunnel syndrome (CTS, rotator cuff syndrome and arthrosis. Methods Cohorts of all male Danish seamen (officers and non-officers and fishermen employed 1994 and 1999 with at least six months employment history were linked to the Occupational Hospitalisation Register. We calculated standardised incidence ratios (SIR for the two time periods, using rates for the entire Danish workforce as a reference. Results Among fishermen, we found high SIRs for knee arthrosis, thoraco-lumbar disc disorders, injuries and statistically significant SIRs above 200 were seen for both rotator cuff syndrome and CTS. The SIR was augmented for injuries and reduced for hip arthrosis between the two time periods. The SIRs for injuries and CTS were high for non-officers. A sub-analysis revealed that the highest risk for CTS was found among male non-officers working as deck crew, SIR 233 (95% CI: 166–317 based on 40 cases. Among officers, the SIRs for injuries and MSDs were low. The number of employed Danish fishermen declined with 25% 1994–1999 to 3470. Short-term employments were common. None of the SIRs increased with increasing length of employment. Conclusion Both fishermen and non-officers have high SIRs for injuries and fishermen also for MSD. Only the SIR for injuries among fishermen was augmented between 1994 and 1999. Our findings suggest an association between the incidence of rotator cuff syndrome and CTS and work within fishery. Long-term cumulative effects of employment were not shown for any of the disease outcomes. Other conditions may play a role.

  2. Can Tidal Current Energy Provide Base Load?

    Directory of Open Access Journals (Sweden)

    Simone Giorgi

    2013-06-01

    Full Text Available Tidal energy belongs to the class of intermittent but predictable renewable energy sources. In this paper, we consider a compact set of geographically diverse locations, which have been assessed to have significant tidal stream energy, and attempt to find the degree to which the resource in each location should be exploited so that the aggregate power from all locations has a low variance. An important characteristic of the locations chosen is that there is a good spread in the peak tidal flow times, though the geographical spread is relatively small. We assume that the locations, all on the island of Ireland, can be connected together and also assume a modular set of tidal turbines. We employ multi-objective optimisation to simultaneously minimise variance, maximise mean power and maximise minimum power. A Pareto front of optimal solutions in the form of a set of coefficients determining the degree of tidal energy penetration in each location is generated using a genetic algorithm. While for the example chosen the total mean power generated is not great (circa 100 MW, the case study demonstrated a methodology that can be applied to other location sets that exhibit similar delays between peak tidal flow times.

  3. Determination of the number of atoms present in nano contact based on shot noise measurements with highly stable nano-fabricated electrodes.

    Science.gov (United States)

    Takahashi, Ryoji; Kaneko, Satoshi; Marqués-González, Santiago; Fujii, Shintaro; Nishino, Tomoaki; Tsukagoshi, Kazuhito; Kiguchi, Manabu

    2016-07-22

    A highly stable experimental setup was developed for the measurement of shot noise in atomic contacts and molecular junctions to determine the number of atoms or molecules present. The use of a nano-fabricated mechanically controllable break junction (MCBJ) electrode improved the overall stability of the experimental setup. The improved stability of the system and optimization of measurement system enabled us to comprehensively investigate the shot noise as well as charge transport properties in Au atomic contacts and molecular junctions. We present a solid proof that the number of atoms (cross sectional atom) in the Au atomic contacts was exactly one. In the atomic contacts, contribution from the additional channels was under the detection limit. Furthermore, the effect of molecular adsorption on the charge transport in the Au atomic contact was investigated. Additional transport channels were opened by exposing pyrazine molecules to the Au contacts, which gave rise to an increase in the Fano factor in the shot noise. PMID:27291763

  4. Determination of the number of atoms present in nano contact based on shot noise measurements with highly stable nano-fabricated electrodes

    Science.gov (United States)

    Takahashi, Ryoji; Kaneko, Satoshi; Marqués-González, Santiago; Fujii, Shintaro; Nishino, Tomoaki; Tsukagoshi, Kazuhito; Kiguchi, Manabu

    2016-07-01

    A highly stable experimental setup was developed for the measurement of shot noise in atomic contacts and molecular junctions to determine the number of atoms or molecules present. The use of a nano-fabricated mechanically controllable break junction (MCBJ) electrode improved the overall stability of the experimental setup. The improved stability of the system and optimization of measurement system enabled us to comprehensively investigate the shot noise as well as charge transport properties in Au atomic contacts and molecular junctions. We present a solid proof that the number of atoms (cross sectional atom) in the Au atomic contacts was exactly one. In the atomic contacts, contribution from the additional channels was under the detection limit. Furthermore, the effect of molecular adsorption on the charge transport in the Au atomic contact was investigated. Additional transport channels were opened by exposing pyrazine molecules to the Au contacts, which gave rise to an increase in the Fano factor in the shot noise.

  5. Acoustic energy harvesting based on a planar acoustic metamaterial

    Science.gov (United States)

    Qi, Shuibao; Oudich, Mourad; Li, Yong; Assouar, Badreddine

    2016-06-01

    We theoretically report on an innovative and practical acoustic energy harvester based on a defected acoustic metamaterial (AMM) with piezoelectric material. The idea is to create suitable resonant defects in an AMM to confine the strain energy originating from an acoustic incidence. This scavenged energy is converted into electrical energy by attaching a structured piezoelectric material into the defect area of the AMM. We show an acoustic energy harvester based on a meta-structure capable of producing electrical power from an acoustic pressure. Numerical simulations are provided to analyze and elucidate the principles and the performances of the proposed system. A maximum output voltage of 1.3 V and a power density of 0.54 μW/cm3 are obtained at a frequency of 2257.5 Hz. The proposed concept should have broad applications on energy harvesting as well as on low-frequency sound isolation, since this system acts as both acoustic insulator and energy harvester.

  6. Bearing Stresses in Bolted Composite Joints with Different Contact Interactions.

    Directory of Open Access Journals (Sweden)

    Hilton Ahmad

    2016-04-01

    Full Text Available In a bolted joint, it has been shown to be better to model the real contact between bolt and hole than to fix the boundary of the hole edge, a practice used by most previous researchers. Master-slave interaction was implemented in ABAQUS to simulate full contact conditions. Stress distributions were plotted along net-tension plane and hole boundary. Due to geometric non-linearity, the clearance and friction coefficients used substantially effected the maximum stress on hole boundary as shown using the benchmarking work of Eriksson. A physically-based constitutive model used is based on state-of-the art fracture mechanics was used for bolted joint strength prediction. Idealized models from Hollmann were remodelled both by fixing the hole boundary (following the original author and by implementing full contact condition using CZM and XFEM. The physically-based constitutive law used independently measured of unnotched strength and fracture energy parameter for crack opening, which is calibrated from available literatures (known as apparent fracture energy. Good correlation with experimental results was found when using the real contact condition.

  7. Scientific Opinion on the safety assessment of the process “ILPA”, based on Starlinger Decon technology, used to recycle post-consumer PET into food contact materials

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2014-04-01

    Full Text Available This scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety assessment of the recycling process ILPA (EU register No RECYC105 which is based on the Starlinger Decon technology. The input of the process is hot caustic washed and dried PET flakes originating from collected post-consumer PET containers, mainly bottles and trays, containing no more than 5 % of PET from non-food consumer applications. Through this technology washed and dried PET flakes are pre-heated before being solid state polymerised (SSP in a continuous reactor at high temperature under vacuum and gas flow. Having examined the challenge test provided, the Panel concluded that the pre-heating (step 2 and the decontamination in the continuous SSP reactor (step 3 are the critical steps that determine the decontamination efficiency of the process. The operating parameters to control their performance are well defined and are the temperature, the pressure, the residence time and the gas flow for step 2 and 3. Under these conditions, it was demonstated that the recycling process under evaluation, is able to ensure that the level of migration of potential unknown contaminants into food is below a conservatively modelled migration of 0.1 μg/kg food. Therefore, the recycled PET obtained from this process intended to be used up to 100 % for the manufacture of materials and articles for contact with all types of foodstuffs for long term storage at room temperature, with or without hotfill, is not considered of safety concern.

  8. Effects of porous flow field type separators using sintered Ni-based alloy powders on interfacial contact resistances and fuel cell performances

    International Nuclear Information System (INIS)

    The novel separators with a porous flow field using sintered corrosion resistant Ni-base alloy C276 (Ni–16Cr–16Mo–5Fe–4W mass%) powders or SUS316L (Fe–17Cr–12Ni–2Mo mass%) powders are investigated for proton exchange membrane fuel cells to enhance power density, which is one of the most important challenges for the widespread use of fuel cells. The developed separator with C276 powders demonstrated low ICRs (interfacial contact resistance) less than 10 mΩ cm2 between separators and GDLs (gas diffusion layers), and it extensively enhanced power density by 90% higher than a conventional graphite separator. This is due to the superior adherence mechanism between the convex surfaces of the spherical powders and porous GDLs as well as the Ni concentration in passive oxide films in powder surfaces. Furthermore, this developed separator shows potential for using without an expensive conductive coating such as Au coating, which has been usually employed to lower ICRs for metallic separators with passive oxide films. In addition, the amount of eluted Cr, which could deteriorate catalyst and cell performance, from sintered C276 powders in a 1 mass% sulfuric acid aqueous solution is reduced by approximately 82% than SUS316L powders. - Highlights: • A flow field of sintered Ni alloy powder reduces interfacial contact resistance. • A separator with a porous flow field of Ni alloy powders enhances cell performance. • Vacuum sintered Ni alloy powders show superior corrosion resistance. • Sintered Ni alloy separators without gold coating show good cell performance

  9. Management of a power system based on renewable energy

    Directory of Open Access Journals (Sweden)

    Ronay Karoly

    2012-06-01

    Full Text Available This article main purpose is to highlight the main advantage of the hardware and software implementation for an energy management system based on renewable energy sources. By using implemented and dedicated hardware and software the evolution of energy production and consumption can be monitored. The advantages of such system are highlighted by the results obtained from experimental simulations. An experimental model for the power system based on renewable energy sources was implemented, where the actual status of the system in different situations when the equipments change their own statuses can be shown.

  10. Graphene and graphene-based materials for energy storage applications.

    Science.gov (United States)

    Zhu, Jixin; Yang, Dan; Yin, Zongyou; Yan, Qingyu; Zhang, Hua

    2014-09-10

    With the increased demand in energy resources, great efforts have been devoted to developing advanced energy storage and conversion systems. Graphene and graphene-based materials have attracted great attention owing to their unique properties of high mechanical flexibility, large surface area, chemical stability, superior electric and thermal conductivities that render them great choices as alternative electrode materials for electrochemical energy storage systems. This Review summarizes the recent progress in graphene and graphene-based materials for four energy storage systems, i.e., lithium-ion batteries, supercapacitors, lithium-sulfur batteries and lithium-air batteries.

  11. Ferromagnetic tunnel contacts to graphene: Contact resistance and spin signal

    Energy Technology Data Exchange (ETDEWEB)

    Cubukcu, M.; Laczkowski, P.; Vergnaud, C.; Marty, A.; Attané, J.-P.; Notin, L.; Vila, L., E-mail: laurent.vila@cea.fr; Jamet, M. [University Grenoble Alpes, CEA, INAC-SP2M, F-38054 Grenoble (France); Martin, M.-B.; Seneor, P.; Anane, A.; Deranlot, C.; Fert, A. [Unité Mixte de Physique CNRS-Thales, F-91767 Palaiseau (France); Auffret, S. [University Grenoble Alpes, CNRS, CEA, INAC-SPINTEC, Grenoble F-38054 (France); Ducruet, C. [Crocus Technology, 4 place Robert Schuman, 38000 Grenoble (France)

    2015-02-28

    We report spin transport in CVD graphene-based lateral spin valves using different magnetic contacts. We compared the spin signal amplitude measured on devices where the cobalt layer is directly in contact with the graphene to the one obtained using tunnel contacts. Although a sizeable spin signal (up to ∼2 Ω) is obtained with direct contacts, the signal is strongly enhanced (∼400 Ω) by inserting a tunnel barrier. In addition, we studied the resistance-area product (R.A) of a variety of contacts on CVD graphene. In particular, we compared the R.A products of alumina and magnesium oxide tunnel barriers grown by sputtering deposition of aluminum or magnesium and subsequent natural oxidation under pure oxygen atmosphere or by plasma. When using an alumina tunnel barrier on CVD graphene, the R.A product is high and exhibits a large dispersion. This dispersion can be highly reduced by using a magnesium oxide tunnel barrier, as for the R.A value. This study gives insight in the material quest for reproducible and efficient spin injection in CVD graphene.

  12. A Net Energy-based Analysis for a Climate-constrained Sustainable Energy Transition

    CERN Document Server

    Sgouridis, Sgouris; Csala, Denes

    2015-01-01

    The transition from a fossil-based energy economy to one based on renewable energy is driven by the double challenge of climate change and resource depletion. Building a renewable energy infrastructure requires an upfront energy investment that subtracts from the net energy available to society. This investment is determined by the need to transition to renewable energy fast enough to stave off the worst consequences of climate change and, at the same time, maintain a sufficient net energy flow to sustain the world's economy and population. We show that a feasible transition pathway requires that the rate of investment in renewable energy should accelerate approximately by an order of magnitude if we are to stay within the range of IPCC recommendations.

  13. Sex Differences in the Effects of Visual Contact and Eye Contact in Negotiations

    OpenAIRE

    Swaab, Roderick I.; Swaab, Dick F.

    2008-01-01

    "Previous research has proposed that the ability to see others would benefit negotiations. We argue that this view is too narrow and that the impact of visual contact on negotiated agreements depends on the meaning individuals ascribe to either its presence or absence. Based on previous research showing that females are more likely to understand others in the presence of visual contact while males understand others better in the absence of visual contact, we explore how visual contact, eye co...

  14. Wind Energy Conversion Based on Matrix Converter

    Directory of Open Access Journals (Sweden)

    Mutharasan Anburaj

    2014-07-01

    Full Text Available In recent years renewable sources such as solar, wave and wind are used for the generation of electricity. Wind is one of the major renewable sources. The amount of energy from a Wind Energy Conversion System (WECS depends not only on the wind at the site, but also on the control strategy used for the WECS. In assistance to get the appropriate wind energy from the conversion system, wind turbine generator will be run in variable speed mode. The variable speed capability is achieved through the use of an advanced power electronic converter. Fixed speed wind turbines and induction generators are often used in wind farms. But the limitations of such generators are low efficiency and poor power quality which necessitates the variable speed wind turbine generators such as Doubly Fed Induction Generator (DFIG and Permanent Magnet Synchronous Generator (PMSG. A high-performance configuration can be obtained by using Scherbius drive composed of a DFIG and a converter in combination AC-DC-AC connect between stator & rotor points for providing the required variable speed operation

  15. Pyroelectric Energy Harvesting: With Thermodynamic-Based Cycles

    Directory of Open Access Journals (Sweden)

    Saber Mohammadi

    2012-01-01

    Full Text Available This work deals with energy harvesting from temperature variations using ferroelectric materials as a microgenerator. The previous researches show that direct pyroelectric energy harvesting is not effective, whereas thermodynamic-based cycles give higher energy. Also, at different temperatures some thermodynamic cycles exhibit different behaviours. In this paper pyroelectric energy harvesting using Lenoir and Ericsson thermodynamic cycles has been studied numerically and the two cycles were compared with each other. The material used is the PMN-25 PT single crystal that is a very interesting material in the framework of energy harvesting and sensor applications.

  16. Fabrication and characterization of a sandpaper-based flexible energy storage

    Science.gov (United States)

    Shieh, Jen-Yu; Wu, Cheng-Hung; Tsai, Sung-Ying; Yu, Hsin Her

    2016-02-01

    In this paper, graphene and carbon nanotubes dispersed in a pectin solution are examined as a precursor for electrode fabrication for supercapacitor applications. The carbon nanotubes not only prevent the stacking of graphene sheets, but also act as spacers and binders. Dropping the hybrid conductive suspension onto sandpaper is found to form a sandpaper-based electrode that improves the specific capacitance of a subsequently fabricated supercapacitor because of its high surface area. In particular, the large contact surface of the sandpaper allows it to absorb more electrolyte ions and increases the number of ions assembled on the electrode surface. For the supercapacitor fabrication, replacing the liquid or solid electrolyte with a gel electrolyte prevents leakage and contact discontinuity. Therefore, a high-performance supercapacitor can be constructed with one separator coated with a gel electrolyte inserted between two fine-sandpaper-based electrodes, which can be assembled into a sandwich structure by hot pressing. Electrochemical analysis shows excellent cycle stability and flexibility of the fine-sandpaper-based supercapacitor. Because of the simple and low-cost assembly of this flexible and lightweight supercapacitor, it has potential applications in many energy storage fields, including wearable electronics and flexible products.

  17. Model Property Based Material Balance and Energy Conservation Analysis for Process Industry Energy Transfer Systems

    OpenAIRE

    Fumin Ma; O’Hare, Gregory M.P.; Tengfei Zhang; Michael J. O’Grady

    2015-01-01

    Conventional historical data based material and energy balance analyses are static and isolated computations. Such methods cannot embody the cross-coupling effect of energy flow, material flow and information flow in the process industry; furthermore, they cannot easily realize the effective evaluation and comparison of different energy transfer processes by alternating the model module. In this paper, a novel method for material balance and energy conservation analysis of process industry en...

  18. Recent Progress on PZT Based Piezoelectric Energy Harvesting Technologies

    Directory of Open Access Journals (Sweden)

    Min-Gyu Kang

    2016-02-01

    Full Text Available Energy harvesting is the most effective way to respond to the energy shortage and to produce sustainable power sources from the surrounding environment. The energy harvesting technology enables scavenging electrical energy from wasted energy sources, which always exist everywhere, such as in heat, fluids, vibrations, etc. In particular, piezoelectric energy harvesting, which uses a direct energy conversion from vibrations and mechanical deformation to the electrical energy, is a promising technique to supply power sources in unattended electronic devices, wireless sensor nodes, micro-electronic devices, etc., since it has higher energy conversion efficiency and a simple structure. Up to now, various technologies, such as advanced materials, micro- and macro-mechanics, and electric circuit design, have been investigated and emerged to improve performance and conversion efficiency of the piezoelectric energy harvesters. In this paper, we focus on recent progress of piezoelectric energy harvesting technologies based on PbZrxTi1-xO3 (PZT materials, which have the most outstanding piezoelectric properties. The advanced piezoelectric energy harvesting technologies included materials, fabrications, unique designs, and properties are introduced to understand current technical levels and suggest the future directions of piezoelectric energy harvesting.

  19. Current-voltage characteristics of quantum-point contacts in the closed-channel regime: Transforming the bias voltage into an energy scale

    DEFF Research Database (Denmark)

    Gloos, K.; Utko, P.; Aagesen, M.;

    2006-01-01

    .2 mu m) contacts are typically found to consist of very short (similar to 0.2 mu m) barriers. We have mapped the height of the barrier as a function of the gate voltage, and found that its behavior differs strongly from that extrapolated using conventional bias spectroscopy in the open-channel regime......We investigate the I(V) characteristics (current versus bias voltage) of side-gated quantum-point contacts, defined in GaAs/AlxGa1-xAs heterostructures. These point contacts are operated in the closed-channel regime, that is, at fixed gate voltages below zero-bias pinch-off for conductance. Our...... we are using the channel length remains the only adjustable parameter since the barrier height can be experimentally determined. For short (similar to 0.06 mu m) contacts, the I(V)-derived lengths agree rather well with those estimated from the geometrical layout, whereas nominally long (similar to 1...

  20. Sea wave energy based in nanotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Duque, Carlos

    2010-09-15

    Application on which it turns east document is the recovery of the energy of the sea waves turning it into electricity by means of the combination of nano-piezoelectric and condensing, the system would be seen like a compound floating fabric of million piezoelectric crystals that turn the oscillating movement of the sea into micro-electrical signals that they are added and they left by means cables to the surface where electronics devices classified to the load of condensers, from the electricity is confined and later is invested and synchronize itself with the great national mains.

  1. Convenient method for resolving degeneracies due to symmetry of the magnetic susceptibility tensor and its application to pseudo contact shift-based protein–protein complex structure determination

    International Nuclear Information System (INIS)

    Pseudo contact shifts (PCSs) induced by paramagnetic lanthanide ions fixed in a protein frame provide long-range distance and angular information, and are valuable for the structure determination of protein–protein and protein–ligand complexes. We have been developing a lanthanide-binding peptide tag (hereafter LBT) anchored at two points via a peptide bond and a disulfide bond to the target proteins. However, the magnetic susceptibility tensor displays symmetry, which can cause multiple degenerated solutions in a structure calculation based solely on PCSs. Here we show a convenient method for resolving this degeneracy by changing the spacer length between the LBT and target protein. We applied this approach to PCS-based rigid body docking between the FKBP12-rapamycin complex and the mTOR FRB domain, and demonstrated that degeneracy could be resolved using the PCS restraints obtained from two-point anchored LBT with two different spacer lengths. The present strategy will markedly increase the usefulness of two-point anchored LBT for protein complex structure determination.

  2. Sutures and contact homology I

    OpenAIRE

    Colin, Vincent; Ghiggini, Paolo; Honda, Ko; Hutchings, Michael

    2010-01-01

    We define a relative version of contact homology for contact manifolds with convex boundary, and prove basic properties of this relative contact homology. Similar considerations also hold for embedded contact homology.

  3. Energy saving behaviours: Development of a practice-based model

    International Nuclear Information System (INIS)

    Financial pressure and concern for the environment has meant many consumers are aware of the need to reduce their consumption of many resources, including energy, which is the focus of the present study. While potential energy use deterrents in the form of access constraints and price increases are forms of extrinsic control, it is not clear how effective these are at reducing consumption and, indeed, it is not clear if such measures are consistent with people's underlying energy saving motivations. Beyond behavioural motivations, people's desires to reduce energy can be thwarted (barriers) and/or supported by a variety of factors, some within their control, while others are perhaps less so. Using a practice-based framework and a qualitative focus group approach, this study presents an exploratory study of these issues. Policy suggestions for overcoming barriers, as well suggestions as to how energy saving behaviours can be supported are offered. - Highlights: • We obtained consumers views about energy saving motivations, barriers and support. • Attitudes towards energy saving are not sufficient to change behaviours. • A practice-based approach to understanding energy saving behaviours is applied. • A practice-based energy-cultures framework (PBECF) is developed. • Barriers and support factors are identified that can be conceptualised within a PBECF

  4. Monitoring and optimization of energy consumption of base transceiver stations

    International Nuclear Information System (INIS)

    The growth and development of the mobile phone network has led to an increased demand for energy by the telecommunications sector, with a noticeable impact on the environment. Monitoring of energy consumption is a great tool for understanding how to better manage this consumption and find the best strategy to adopt in order to maximize reduction of unnecessary usage of electricity. This paper reports on a monitoring campaign performed on six BSs (Base Transceiver Stations) located central Italy, with different technology, typology and technical characteristics. The study focuses on monitoring energy consumption and environmental parameters (temperature, noise, and global radiation), linking energy consumption with the load of telephone traffic and with the air conditioning functions used to cool the transmission equipment. Moreover, using experimental data collected, it is shown, with a Monte Carlo simulation based on power saving features, how the BS monitored could save energy. - Highlights: • Energy consumption and environmental parameters of a base transceiver system have been monitored. • Energy consumption is related to the air conditioning functions and to the load of telephone traffic. • Energy saving can be obtained by careful choice of cooling parameters and by turn off BS transceivers. • Energy saving parameters can be estimated by a simulation Monte Carlo method

  5. Energy demand forecasting method based on international statistical data

    International Nuclear Information System (INIS)

    Poland is in a transition phase from a centrally planned to a market economy; data collected under former economic conditions do not reflect a market economy. Final energy demand forecasts are based on the assumption that the economic transformation in Poland will gradually lead the Polish economy, technologies and modes of energy use, to the same conditions as mature market economy countries. The starting point has a significant influence on the future energy demand and supply structure: final energy consumption per capita in 1992 was almost half the average of OECD countries; energy intensity, based on Purchasing Power Parities (PPP) and referred to GDP, is more than 3 times higher in Poland. A method of final energy demand forecasting based on regression analysis is described in this paper. The input data are: output of macroeconomic and population growth forecast; time series 1970-1992 of OECD countries concerning both macroeconomic characteristics and energy consumption; and energy balance of Poland for the base year of the forecast horizon. (author). 1 ref., 19 figs, 4 tabs

  6. High-energy attosecond nanoplasmonic-based electron gun

    Science.gov (United States)

    Greig, S. R.; Elezzabi, A. Y.

    2016-03-01

    We present the design of an ultrafast conical lens based nanoplasmonic electron gun. Through excitation with a radially polarized laser pulse, and a combination of magnetostatic and spatial filtering, high energy electron packets with attosecond durations can be achieved.

  7. Dissipation of vibration in rough contact

    OpenAIRE

    Le Bot, Alain; Bou-Chakra, Elie; Michon, Guilhem

    2011-01-01

    The relationship which links the normal vibration occurring during the sliding of rough surfaces and the nominal contact area is investigated. Two regimes are found. In the first one, the vibrational level does not depend on the contact area, while in the second one, it is propor- tional to the contact area. A theoretical model is proposed. It is based on the assumption that the vibrational level results from a competition between two processes of vibration damping, the internal damping of th...

  8. Proposed ICDRG Classification of the Clinical Presentation of Contact Allergy

    DEFF Research Database (Denmark)

    Pongpairoj, Korbkarn; Ale, Iris; Andersen, Klaus Ejner;

    2016-01-01

    The International Contact Dermatitis Research Group proposes a classification for the clinical presentation of contact allergy. The classification is based primarily on the mode of clinical presentation. The categories are direct exposure/contact dermatitis, mimicking or exacerbation of preexisti....../mucosal symptoms, oral contact dermatitis, erythroderma/exfoliative dermatitis, minor forms of presentation, and extracutaneous manifestations.......The International Contact Dermatitis Research Group proposes a classification for the clinical presentation of contact allergy. The classification is based primarily on the mode of clinical presentation. The categories are direct exposure/contact dermatitis, mimicking or exacerbation of preexisting...

  9. Combined Cycle Fatigue Investigation Based on Energy Principle

    OpenAIRE

    Kalynenko Mykyta

    2016-01-01

    We present a modified energy-principle based model of fatigue damage accumulation in high temperature alloys usually used in gas turbine engine under combined high cycle fatigue and low cycle fatigue (LCF/HCF) loading conditions. Our model is based on the energy principle which includes a modified approximation formula that describes fatigue crack origin depending on the relative amplitude of stress intensity in the ranges of both high- and low-cycle fatigue under non-isothermal loading. Func...

  10. Contact Hamiltonian Mechanics

    CERN Document Server

    Bravetti, Alessandro; Tapias, Diego

    2016-01-01

    In this work we introduce contact Hamiltonian mechanics, an extension of symplectic Hamiltonian mechanics, and show that it is a natural candidate for a geometric description of non-dissipative and dissipative systems. For this purpose we review in detail the major features of standard symplectic Hamiltonian dynamics and show that all of them can be generalized to the contact case.

  11. Screw bondgraph contact dynamics

    NARCIS (Netherlands)

    Visser, Martijn; Stramigioli, Stefano; Heemskerk, Cock

    2002-01-01

    This paper presents an elegant contact dynamics model in screw bondgraph form. It can model the contact between any two objects of finite curvature. It does so by defining a Gauss frame on the surfaces of both objects in the points that are closest to each other. Then it describes how the Gauss fram

  12. Contact dermatitis. A review

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Benezra, C; Burrows, D;

    1987-01-01

    In recent years, there has been a dramatic rise in our understanding of contact dermatitis. This paper is a review of our knowledge of the mechanisms involved in contact dermatitis and related phenomena, the investigation of these events and the emergence of significant new allergens during the...

  13. Action dependent heuristic dynamic programming based residential energy scheduling with home energy inter-exchange

    International Nuclear Information System (INIS)

    Highlights: • The algorithm is developed in the two-household energy management environment. • We develop the absent energy penalty cost for the first time. • The algorithm has ability to keep adapting in real-time operations. • Its application can lower total costs and achieve better load balancing. - Abstract: Residential energy scheduling is a hot topic nowadays in the background of energy saving and environmental protection worldwide. To achieve this objective, a new residential energy scheduling algorithm is developed for energy management, based on action dependent heuristic dynamic programming. The algorithm works under the circumstance of residential real-time pricing and two adjacent housing units with energy inter-exchange, which can reduce the overall cost and enhance renewable energy efficiency after long-term operation. It is designed to obtain the optimal control policy to manage the directions and amounts of electricity energy flux. The algorithm’s architecture is mainly constructed based on neural networks, denoting the learned characteristics in the linkage of layers. To get close to real situations, many constraints such as maximum charging/discharging power of batteries are taken into account. The absent energy penalty cost is developed for the first time as a part of the performance index function. When the environment changes, the residential energy scheduling algorithm gains new features and keeps adapting in real-time operations. Simulation results show that the developed algorithm is beneficial to energy conversation

  14. Electrical contacts to individual SWCNTs: A review

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2014-11-01

    Full Text Available Owing to their superior electrical characteristics, nanometer dimensions and definable lengths, single-walled carbon nanotubes (SWCNTs are considered as one of the most promising materials for various types of nanodevices. Additionally, they can be used as either passive or active elements. To be integrated into circuitry or devices, they are typically connected with metal leads to provide electrical contacts. The properties and quality of these electrical contacts are important for the function and performance of SWCNT-based devices. Since carbon nanotubes are quasi-one-dimensional structures, contacts to them are different from those for bulk semiconductors. Additionally, some techniques used in Si-based technology are not compatible with SWCNT-based device fabrication, such as the contact area cleaning technique. In this review, an overview of the investigations of metal–SWCNT contacts is presented, including the principle of charge carrier injection through the metal–SWCNT contacts and experimental achievements. The methods for characterizing the electrical contacts are discussed as well. The parameters which influence the contact properties are summarized, mainly focusing on the contact geometry, metal type and the cleanliness of the SWCNT surface affected by the fabrication processes. Moreover, the challenges for widespread application of CNFETs are additionally discussed.

  15. Feasibility and impact analysis of a renewable energy source (RES)-based energy system in Korea

    International Nuclear Information System (INIS)

    In this study, we analyze the feasibility and impacts of a renewable energy source (RES)-based electricity supply system of future Korea. To achieve this goal, we first developed different scenarios for increasing the contribution of RES by lowering the rate of i) nuclear power, ii) thermal power, iii) both nuclear and thermal power, and iv) these scenarios with real-world constraints. Based on the generated scenarios, we then specified the established systems with practical strategies which encourage different renewable sources (wind, solar photovoltaic, biomass, and waste). Finally, we analyzed the impacts of the established RES-based systems according to various criteria: the total required cost, the dependence on imported energy, CO2 emissions, and land use. The results show that the RES-based system that utilizes wind energy as its main source by steadily decreasing the rate of thermal power for electricity generation is the most affordable for future Korean electricity system. We also identify the merits and drawbacks of the analyzed systems and provide relevant recommendations for the establishment of a sustainable energy system for Korea. These findings will support policy makers in integrating quantitative assessments into energy-related policy design and implementation. - Highlights: • We model and analyze RES-based electricity supply system in Korea. • Impact analysis includes: economic, energy security, environmental protection aspects. • We also evaluate different strategies to establish RES-based system. • We show that wind energy-based system is the most affordable for Korea

  16. Thermal contact resistance measurement of conduction cooled binary current lead joint block in cryocooler based self field I-V characterization facility

    Science.gov (United States)

    Kundu, Ananya; Das, Subrat Kumar; Agarwal, Anees Bano Pooja; Pradhan, Subrata

    2016-05-01

    In the present study thermal resistance of conduction cooled current lead joint block employing two different interfacial material namely AlN sheet and Kapton Film have been studied in the temperature range 5K-35K. In each case, the performance of different interlayer materials e.g. Indium foil for moderately pressurized contacts (contact pressure <1 MPa), and Apiezon N Grease, GE varnish for low pressurized contact (contact pressure <1 MPa) is studied. The performances of AlN joint with Indium foil and with Apeizon N Grease are studied and it is observed that the contact resistance reduces more with indium foil as compared to greased contact. The contact resistance measurements of Kapton film with Apiezon N grease and with GE varnish were also carried out in the same temperature range. A comparative study of AlN joint with Indium foil and Kapton with GE varnish as filler material is carried out to demonstrate better candidate material among Kapton and AlN for a particular filler material in the same temperature range.

  17. Analysis of Cu Diffusion in ZnTe-Based Contacts for Thin-Film CdS/CdTe Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Narayanswamy, C. (Department of Physics & Astronomy, University of Toledo); Gessert, T. A. and Asher, S. E. (National Renewable Energy Laboratory)

    1998-10-27

    Ohmic contacts to thin-film CdS/CdTe photovoltaic devices have been formed using a two-layer contact interface of undoped ZnTe (ZnTe) and Cu-doped ZnTe (ZnTe:Cu), followed by Ni or Ti as an outer metallization. Secondary ion mass spectroscopy (SIMS) is used to study Cu diffusion within this back-contact structure, and also, to monitor Cu diffusion from the contact into the CdTe. When Ni metallization is used, the ZnTe:Cu layer becomes increasingly depleted of Cu, and Ni diffusion into the ZnTe:Cu increases as the contact deposition temperature increases from 100 C to 300 C. Cu depletion is not observed when Ni is replaced with Ti. Diffusion of Cu from the ZnTe:Cu layer into the ZnTe layer also increases with contact deposition temperature, and produces a buildup of Cu at the ZnTe/CdTe interface. High-mass resolution SIMS indicates that, although Cu levels in the CdTe remain low, Cu diffusion from the contact proceeds into the CdTe layer and toward the CdTe/CdS junction region.

  18. Net-Zero Energy Buildings: A Classification System Based on Renewable Energy Supply Options

    Energy Technology Data Exchange (ETDEWEB)

    Pless, S.; Torcellini, P.

    2010-06-01

    A net-zero energy building (NZEB) is a residential or commercial building with greatly reduced energy needs. In such a building, efficiency gains have been made such that the balance of energy needs can be supplied with renewable energy technologies. Past work has developed a common NZEB definition system, consisting of four well-documented definitions, to improve the understanding of what net-zero energy means. For this paper, we created a classification system for NZEBs based on the renewable sources a building uses.

  19. Formation of Ag/Al Screen-Printing Contacts on B Emitters

    OpenAIRE

    Fritz, Susanne; König, Markus; Riegel, Stefanie; Herguth, Axel; Hörteis, Matthias; Hahn, Giso

    2015-01-01

    In this study, the contact formation process of Al containing Ag screen-printing pastes to BBr3-based B emitters on Si is investigated. Therefore, a detailed scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy study of top-view and cross-sectional samples was conducted. The possible influence of a SiN∞:H antireflection coating was considered by comparing contacts with and without a SiN∞:H layer. To analyze the role of the glass frit in the paste, the contact formation ...

  20. Note: Vibration energy harvesting based on a round acoustic fence.

    Science.gov (United States)

    Cui, Xiao-bin; Huang, Cheng-ping; Hu, Jun-hui

    2015-07-01

    An energy harvester based on a round acoustic fence (RAF) has been proposed and studied. The RAF is composed of cylindrical stubs stuck in a circular array on a thin metal plate, which can confine the acoustic energy efficiently. By removing one stub and thus opening a small gap in the RAF, acoustic leakage with larger intensity can be produced at the gap opening. With the vibration source surrounded by the RAF, the energy harvesting at the gap opening has a wide bandwidth and is insensitive to the position of the vibration source. The results may have potential applications in harvesting the energy of various vibration sources in solid structure. PMID:26233415

  1. Hydrogen-based electrochemical energy storage

    Science.gov (United States)

    Simpson, Lin Jay

    2013-08-06

    An energy storage device (100) providing high storage densities via hydrogen storage. The device (100) includes a counter electrode (110), a storage electrode (130), and an ion conducting membrane (120) positioned between the counter electrode (110) and the storage electrode (130). The counter electrode (110) is formed of one or more materials with an affinity for hydrogen and includes an exchange matrix for elements/materials selected from the non-noble materials that have an affinity for hydrogen. The storage electrode (130) is loaded with hydrogen such as atomic or mono-hydrogen that is adsorbed by a hydrogen storage material such that the hydrogen (132, 134) may be stored with low chemical bonding. The hydrogen storage material is typically formed of a lightweight material such as carbon or boron with a network of passage-ways or intercalants for storing and conducting mono-hydrogen, protons, or the like. The hydrogen storage material may store at least ten percent by weight hydrogen (132, 134) at ambient temperature and pressure.

  2. Role of Ag-alloy in the thermal stability of Ag-based ohmic contact to GaN(0 0 0 1) surface

    International Nuclear Information System (INIS)

    First-principles calculations are performed to study Ag and Ag-alloy adsorption stability on GaN(0 0 0 1) surface. We find Ag only contact to GaN surface is unstable under high temperature. While Ag-alloy adsorption exhibits better adsorption stability and electronic properties than that of the Ag only contact,due to the enhanced interaction between Ag-alloy and GaN(0 0 0 1) surface. The Ag-alloy, particularly AgNi, is proposed to be used as very promising ohmic contact to GaN for practical applications

  3. Almost contact metric 3-submersions

    Directory of Open Access Journals (Sweden)

    Bill Watson

    1984-01-01

    Full Text Available An almost contact metric 3-submersion is a Riemannian submersion, π from an almost contact metric manifold (M4m+3,(φi,ξi,ηii=13,g onto an almost quaternionic manifold (N4n,(Jii=13,h which commutes with the structure tensors of type (1,1;i.e., π*φi=Jiπ*, for i=1,2,3. For various restrictions on ∇φi, (e.g., M is 3-Sasakian, we show corresponding limitations on the second fundamental form of the fibres and on the complete integrability of the horizontal distribution. Concommitantly, relations are derived between the Betti numbers of a compact total space and the base space. For instance, if M is 3-quasi-Saskian (dΦ=0, then b1(N≤b1(M. The respective φi-holomorphic sectional and bisectional curvature tensors are studied and several unexpected results are obtained. As an example, if X and Y are orthogonal horizontal vector fields on the 3-contact (a relatively weak structure total space of such a submersion, then the respective holomorphic bisectional curvatures satisfy: Bφi(X,Y=B′J′i(X*,Y*−2. Applications to the real differential geometry of Yarg-Milis field equations are indicated based on the fact that a principal SU(2-bundle over a compactified realized space-time can be given the structure of an almost contact metric 3-submersion.

  4. A novel optical apparatus for the study of rolling contact wear/fatigue based on a high-speed camera and multiple-source laser illumination.

    Science.gov (United States)

    Bodini, I; Sansoni, G; Lancini, M; Pasinetti, S; Docchio, F

    2016-08-01

    Rolling contact wear/fatigue tests on wheel/rail specimens are important to produce wheels and rails of new materials for improved lifetime and performance, which are able to operate in harsh environments and at high rolling speeds. This paper presents a novel non-invasive, all-optical system, based on a high-speed video camera and multiple laser illumination sources, which is able to continuously monitor the dynamics of the specimens used to test wheel and rail materials, in a laboratory test bench. 3D macro-topography and angular position of the specimen are simultaneously performed, together with the acquisition of surface micro-topography, at speeds up to 500 rpm, making use of a fast camera and image processing algorithms. Synthetic indexes for surface micro-topography classification are defined, the 3D macro-topography is measured with a standard uncertainty down to 0.019 mm, and the angular position is measured on a purposely developed analog encoder with a standard uncertainty of 2.9°. The very small camera exposure time enables to obtain blur-free images with excellent definition. The system will be described with the aid of end-cycle specimens, as well as of in-test specimens. PMID:27587125

  5. Fractal Geometry-Based Hypergeometric Time Series Solution to the Hereditary Thermal Creep Model for the Contact of Rough Surfaces Using the Kelvin-Voigt Medium

    Directory of Open Access Journals (Sweden)

    Osama M. Abuzeid

    2010-01-01

    Full Text Available This paper aims at constructing a continuous hereditary creep model for the thermoviscoelastic contact of a rough punch and a smooth surface of a rigid half-space. The used model considers the rough surface as a function of the applied load and temperatures. The material of the rough punch surface is assumed to behave as Kelvin-Voigt viscoelastic material. Such a model uses elastic springs and viscous dashpots in parallel. The fractal-based punch surface is modelled using a deterministic Cantor structure. An asymptotic power law, deduced using approximate iterative relations, is used to express the punch surface creep which is a time-dependent inelastic deformation. The suggested law utilized the hypergeometric time series to relate the variables of creep as a function of remote forces, body temperatures, and time. The model is valid when the approach of punch surface and half space is in the order of the size of the surface roughness. The closed-form results are obtained for selected values of the system parameters; the fractal surface roughness and various material properties. The obtained results show good agreement with published experimental results, and the methodology can be further extended to other structures such as the Kelvin-Voigt medium within electronic circuits and systems.

  6. A novel optical apparatus for the study of rolling contact wear/fatigue based on a high-speed camera and multiple-source laser illumination

    Science.gov (United States)

    Bodini, I.; Sansoni, G.; Lancini, M.; Pasinetti, S.; Docchio, F.

    2016-08-01

    Rolling contact wear/fatigue tests on wheel/rail specimens are important to produce wheels and rails of new materials for improved lifetime and performance, which are able to operate in harsh environments and at high rolling speeds. This paper presents a novel non-invasive, all-optical system, based on a high-speed video camera and multiple laser illumination sources, which is able to continuously monitor the dynamics of the specimens used to test wheel and rail materials, in a laboratory test bench. 3D macro-topography and angular position of the specimen are simultaneously performed, together with the acquisition of surface micro-topography, at speeds up to 500 rpm, making use of a fast camera and image processing algorithms. Synthetic indexes for surface micro-topography classification are defined, the 3D macro-topography is measured with a standard uncertainty down to 0.019 mm, and the angular position is measured on a purposely developed analog encoder with a standard uncertainty of 2.9°. The very small camera exposure time enables to obtain blur-free images with excellent definition. The system will be described with the aid of end-cycle specimens, as well as of in-test specimens.

  7. Micromachined lead zirconium titanate thin-film-cantilever-based acoustic emission sensor with poly(N-isopropylacrylamide) actuator for increasing contact pressure

    Science.gov (United States)

    Feng, Guo-Hua; Chen, Wei-Ming

    2016-05-01

    This paper presents an innovative acousticemission (AE) sensor with a cantilever sensing structure. A hydrothermal lead zirconium titanate (PZT) film was deposited on the cantilever for AE sensing, and an SU8 micropillar at the free end of the cantilever served as an AE wave coupler; in addition, a poly(N-isopropylacrylamide)-based thermoresponsive actuator was integrated with the cantilever to increase the contact pressure exerted on the target. The AE sensor showed higher performance compared with an existing commercial AE sensor. Micromachining technology was used to fabricate AE sensors, and an array of four sensors was fabricated on a 50 μm thick titanium substrate of dimensions 15 mm × 15 mm. The piezoelectric properties of the hydrothermal PZT film were verified by electrically driving the cantilever and measuring the displacement; the piezoelectric constant d 31 of the cantilever was 2.43 pC N‑1. The output force of the sensing cantilever generated by activating the thermoresponsive actuator was determined. For an electrical power input of 2.5 W, the maximum force output at the SU8 micropillar was 1 N. This force corresponded to the application of a pressure of 1.4 MPa on the target. Pencil lead break tests were conducted to determine and compare the performance of the proposed AE sensor with commercial sensors. Here, experimental and theoretical discussions on the effect of the activation of the thermoresponsive actuator of the proposed AE sensor on AE detection are presented.

  8. Microbiological quality and other characteristics of refrigerated chicken meat in contact with cellulose acetate-based film incorporated with rosemary essential oil

    Directory of Open Access Journals (Sweden)

    Adriane Alexandre Machado de Melo

    2012-12-01

    Full Text Available Antimicrobial active packaging delays or inhibits microorganism growth in packed products, and it can be used in a variety of food systems. The objective of the present research was to develop packaging incorporated with natural antimicrobial agents (active film. The effects of the active film on the spoilage, pathogenic microorganism counts, pH and color of the refrigerated chicken breast cuts were analyzed. Cellulose acetate-based active films incorporating two concentrations (20% and 50%, v/w of rosemary (Rosmarinus officinalis L. essential oil were manufactured and placed in contact with the chicken breast cuts for six days. An analysis of variance and mean comparison tests (Tukey's test, p<0.05 were performed on the results. The films that contained 20% essential oil and were intercalated with chicken breast samples did not demonstrate significant effects on the control of psychrotrophic or total coliform microorganisms during the storage period; however, the films incorporated with 50% essential oil demonstrated efficacy toward the control of coliforms during the storage of the samples (6 days, 2 ± 2ºC. The pH was related to the psychrotrophic microorganism count and was not influenced by the treatment. The color was not influenced by the time of storage or the treatment. The results demonstrate that active films incorporating 50% rosemary essential oil are effective at controlling certain microorganisms in chicken breast cuts.

  9. Material identification based upon energy-dependent attenuation of neutrons

    Science.gov (United States)

    Marleau, Peter

    2015-10-06

    Various technologies pertaining to identifying a material in a sample and imaging the sample are described herein. The material is identified by computing energy-dependent attenuation of neutrons that is caused by presence of the sample in travel paths of the neutrons. A mono-energetic neutron generator emits the neutron, which is downscattered in energy by a first detector unit. The neutron exits the first detector unit and is detected by a second detector unit subsequent to passing through the sample. Energy-dependent attenuation of neutrons passing through the sample is computed based upon a computed energy of the neutron, wherein such energy can be computed based upon 1) known positions of the neutron generator, the first detector unit, and the second detector unit; or 2) computed time of flight of neutrons between the first detector unit and the second detector unit.

  10. FEL based energy driver for inertial confinement fusion

    International Nuclear Information System (INIS)

    An FEL based energy driver for inertial confinement fusion (ICF) is proposed. The key element of the scheme is a free electron laser system. Novel technical solutions reveal a possibility to construct the FEL system operating at a radiation wavelength λ= 0.5 μm and providing a flash energy E 1 MJ and brightness 4 x1022 W cm-2sr-1 within the steering pulse duration 0.1-2 ns. The total energy efficiency of the proposed ICF energy driver is about 11% and repetition rate is 40 Hz. It is shown that the FEL based ICF energy driver may be constructed at the present level of accelerator technique R and D. (orig.)

  11. Monitoring and optimization of energy consumption of base transceiver stations

    CERN Document Server

    Spagnuolo, Antonio; Vetromile, Carmela; Formosi, Roberto; Lubritto, Carmine

    2015-01-01

    The growth and development of the mobile phone network has led to an increased demand for energy by the telecommunications sector, with a noticeable impact on the environment. Monitoring of energy consumption is a great tool for understanding how to better manage this consumption and find the best strategy to adopt in order to maximize reduction of unnecessary usage of electricity. This paper reports on a monitoring campaign performed on six Base Transceiver Stations (BSs) located central Italy, with different technology, typology and technical characteristics. The study focuses on monitoring energy consumption and environmental parameters (temperature, noise, and global radiation), linking energy consumption with the load of telephone traffic and with the air conditioning functions used to cool the transmission equipment. Moreover, using experimental data collected, it is shown, with a Monte Carlo simulation based on power saving features, how the BS monitored could save energy.

  12. High efficiency back-contact back-junction thin-film monocrystalline silicon solar cells from the porous silicon process

    Science.gov (United States)

    Haase, F.; Kajari-Schröder, S.; Brendel, R.

    2013-11-01

    This work demonstrates the fabrication of a 45 μm thick back-contact back-junction thin-film monocrystalline silicon solar cell from the porous silicon process with an energy conversion efficiency of 18.9%. We demonstrate an efficiency improvement of 5.4% absolute compared to our prior record of 13.5% for back-contact back-junction thin-film monocrystalline silicon solar cells. This increase in efficiency is achieved by reducing the recombination at the base contact using a back surface field and by increasing the generation with a front texture. We investigate the loss mechanisms in the cell using finite element simulations. A free energy loss analysis based on experiments and simulations determines the dominating loss mechanisms. The efficiency loss by base recombination is 0.8% absolute and the loss by base contact recombination is 0.5% absolute in the 18.9% efficiency cell.

  13. Friction and wear with a single-crystal abrasive grit of silicon carbide in contact with iron base binary alloys in oil: Effects of alloying element and its content

    Science.gov (United States)

    Miyoshi, K.; Buckley, D. H.

    1979-01-01

    Sliding friction experiments were conducted with various iron-base binary alloys (alloying elements were Ti, Cr, Mn, Ni, Rh, and W) in contact with a rider of 0.025-millimeter-radius, single-crystal silicon carbide in mineral oil. Results indicate that atomic size and content of alloying element play a dominant role in controlling the abrasive-wear and -friction properties of iron-base binary alloys. The coefficient of friction and groove height (wear volume) general alloy decrease, and the contact pressure increases in solute content. There appears to be very good correlation of the solute to iron atomic radius ratio with the decreasing rate of coefficient of friction, the decreasing rate of groove height (wear volume), and the increasing rate of contact pressure with increasing solute content C. Those rates increase as the solute to iron atomic radius ratio increases from unity.

  14. Resource management tools based on renewable energy sources

    Science.gov (United States)

    Jannson, Tomasz; Forrester, Thomas; Boghrat, Pedram; Pradhan, Ranjit; Kostrzewski, Andrew

    2012-06-01

    Renewable energy is an important source of power for unattended sensors (ground, sea, air), tagging systems, and other remote platforms for Homeland Security and Homeland Defense. Also, Command, Control, Communication, and Intelligence (C3I) systems and technologies often require renewable energy sources for information assurance (IA), in general, and anti-tampering (AT), in particular. However, various geophysical and environmental conditions determine different types of energy harvesting: solar, thermal, vibration, acoustic, hydraulic, wind, and others. Among them, solar energy is usually preferable, but, both a solar habitat and the necessity for night operation can create a need for other types of renewable energy. In this paper, we introduce figures of merit (FoMs) for evaluating preferences of specific energy sources, as resource management tools, based on geophysical conditions. Also, Battery Systemic Modeling is discussed.

  15. Energy conservation technologies based on thermodynamic principles

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, Masaru [Shibaura Institute of Technology of Technology, Tokyo (Japan)

    1996-12-31

    In order to reduce CO{sub 2} emission to prevent global warming, the most promising way for electric generation in the Northeast Asia is to introduce cogeneration and {open_quotes}repowering{close_quotes} technologies based on high temperature gas turbines fueled by natural gas. Especially the old type coal burning boiler-steam turbine plants should be retrofit by introducing gas turbines to become highly efficient combined cycle. Same technologies should be applied to the old garbage incineration plants and/or even to the nuclear power plants. The exhaust heat or steam should become much increased and it should be utilized as the process heat for industries or heat supply as the distinct heating or cooling for residential area. This paper introduces a brief survey of these new technologies.

  16. Computational contact mechanics

    CERN Document Server

    Wriggers, Peter

    2006-01-01

    Contact mechanics has its application in many engineering problems. No one can walk without frictional contact, and no car would move for the same r- son. Hence contact mechanics has, from an engineering point of view, a long history, beginning in ancient Egypt with the movement of large stone blocks, over ?rst experimental contributions from leading scientists like Leonardo da Vinci andCoulomb, to today's computational methods. In the past c- tact conditions were often modelled in engineering analysis by more simple boundary conditions since analytical solutions were not present for real worl

  17. Remedial Action Contacts Directory - 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    This document, which was prepared for the US Department of Energy (DOE) Office of Environmental Restoration (ER), is a directory of 2628 individuals interested or involved in environmental restoration and/or remedial actions at radioactively contaminated sites. This directory contains a list of mailing addresses and phone numbers of DOE operations, area, site, project, and contractor offices; an index of DOE operations, area, site, project, and contractor office sorted by state; a list of individuals, presented by last name, facsimile number, and e-mail address; an index of affiliations presented alphabetically, with individual contacts appearing below each affiliation name; and an index of foreign contacta sorted by country and affiliation. This document was generated from the Remedial Action Contacts Database, which is maintained by the Remedial Action Program Information Center (RAPIC).

  18. The comparison between two irrigation regimens on the dentine wettability for an epoxy resin based sealer by measuring its contact angle formed to the irrigated dentine

    Science.gov (United States)

    Mohan, Rayapudi Phani; Pai, Annappa Raghavendra Vivekananda

    2015-01-01

    Aim: The aim was to assess the influence of two irrigation regimens having ethylenediaminetetraacetic acid (EDTA) and ethylenediaminetetraacetic acid with cetrimide (EDTAC) as final irrigants, respectively, on the dentine wettability for AH Plus sealer by comparing its contact angle formed to the irrigated dentine. Materials and Methods: Study samples were divided into two groups (n = 10). The groups were irrigated with 3% sodium hypochlorite (NaOCl) solution followed by either 17% EDTA or 17% EDTAC solution. AH Plus was mixed, and controlled volume droplet (0.1 mL) of the sealer was placed on the dried samples. The contact angle was measured using a Dynamic Contact Angle Analyzer and results were analyzed using SPSS 21.0 and 2 sample t-test. Results: There was a significant difference in the contact angle of AH Plus formed to the dentine irrigated with the above two regimens. AH Plus showed significantly lower contact angle with the regimen having EDTAC as a final irrigant than the one with EDTA (P < 0.05). Conclusion: An irrigation regimen consisting of NaOCl with either EDTA or EDTAC solution as a final irrigant influences the dentine wettability and contact angle of a sealer. EDTAC as a final irrigant facilitates better dentin wettability than EDTA for AH Plus to promote its better flow and adhesion. PMID:26180409

  19. Analysis of renewable energy sources and electric vehicle penetration into energy systems predominantly based on lignite

    CERN Document Server

    Dedinec, Aleksandar; Gajduk, Andrej; Markovska, Natasa; Kocarev, Ljupco

    2016-01-01

    We consider an integration of renewable energy into transport and electricity sectors through vehicle to grid (V2G) technologies for an energy system that is predominantly based on lignite. The national energy system of Macedonia is modeled using EnergyPLAN which integrates energy for electricity, transport and heat, and includes hourly fluctuations in human needs and the environment. We show that electric-vehicles can provide the necessary storage enabling a fully renewable energy profile for Macedonia that can match the country's growing demand for energy. Furthermore, a large penetration of electric vehicles leads to a dramatic reduction of 47% of small particles and other air pollutants generated by car traffic in 2050.

  20. Analysis of renewable energy sources and electric vehicle penetration into energy systems predominantly based on lignite

    Science.gov (United States)

    Dedinec, A.; Jovanovski, B.; Gajduk, A.; Markovska, N.; Kocarev, L.

    2016-05-01

    We consider an integration of renewable energy into transport and electricity sectors through vehicle to grid (V2G) technologies for an energy system that is predominantly based on lignite. The national energy system of Macedonia is modeled using EnergyPLAN which integrates energy for electricity, transport and heat, and includes hourly fluctuations in human needs and the environment. We show that electric-vehicles can provide the necessary storage enabling a fully renewable energy profile for Macedonia that can match the country's growing demand for energy. Furthermore, a large penetration of electric vehicles leads to a dramatic reduction of 47% of small particles and other air pollutants generated by car traffic in 2050.

  1. Design of energy-based terrain following flight control system

    Science.gov (United States)

    Wang, Wei; Li, Aijun; Xie, Yanwu; Tan, Jian

    2006-11-01

    Historically, aircraft longitudinal control has been realized by means of two loops: flight path (the control variable is elevator displacement) and speed control (the control variable is propulsive thrust or engine power). Both the elevator and throttle control cause coupled altitude and speed response, which exerts negative effects on longitudinal flight performance of aircraft, especially for Terrain Following(TF) flight. Energy-based method can resolve coupled problem between flight speed and path by controlling total energy rate and energy distribution rate between elevator and throttle. In this paper, energy-based control method is applied to design a TF flight control system for controlling flight altitude directly. An error control method of airspeed and altitude is adopted to eliminate the stable error of the total energy control system when decoupling control. Pitch loop and pitch rate feedback loop are designed for the system to damp the oscillatory response produced by TF system. The TF flight control system structure diagram and an aircraft point-mass energy motion model including basic control loops are given and used to simulate decoupling performance of the TF fight control system. Simulation results show that the energy-based TF flight control system can decouple flight velocity and flight path angle, exactly follow planned flight path, and greatly reduce altitude error, which is between +10m and -8m.

  2. UV-curable low surface energy fluorinated polycarbonate-based polyurethane dispersion.

    Science.gov (United States)

    Hwang, Hyeon-Deuk; Kim, Hyun-Joong

    2011-10-15

    UV-curable low surface energy fluorinated polycarbonate-based polyurethane dispersions were synthesized by incorporating a hydroxy-terminated perfluoropolyether (PFPE) into the soft segment of polyurethane. The effects of the PFPE content on the UV-curing behavior, physical, surface, thermal properties and refractive index were investigated. The UV-curing behavior was analyzed by photo-differential scanning calorimetry. The surface free energy of the UV-cured film, which is related to the water or oil repellency, was calculated from contact angle measurements using the Lewis acid-base three liquids method. The surface free energy decreased significantly with increasing fluorine concentration because PFPE in the soft segment was tailored to the surface and produced a UV-cured film with a hydrophobic fluorine enriched surface, as confirmed by X-ray photoelectron spectroscopy. With increasing the fluorine content, the refractive indices of UV-cured films decreased. However, the UV-curing rate and final conversion was decreased with increasing contents of PFPE, which resulted in the decrease of the glass transition temperature (T(g)), crosslink density, tensile strength and surface hardness.

  3. UV-curable low surface energy fluorinated polycarbonate-based polyurethane dispersion.

    Science.gov (United States)

    Hwang, Hyeon-Deuk; Kim, Hyun-Joong

    2011-10-15

    UV-curable low surface energy fluorinated polycarbonate-based polyurethane dispersions were synthesized by incorporating a hydroxy-terminated perfluoropolyether (PFPE) into the soft segment of polyurethane. The effects of the PFPE content on the UV-curing behavior, physical, surface, thermal properties and refractive index were investigated. The UV-curing behavior was analyzed by photo-differential scanning calorimetry. The surface free energy of the UV-cured film, which is related to the water or oil repellency, was calculated from contact angle measurements using the Lewis acid-base three liquids method. The surface free energy decreased significantly with increasing fluorine concentration because PFPE in the soft segment was tailored to the surface and produced a UV-cured film with a hydrophobic fluorine enriched surface, as confirmed by X-ray photoelectron spectroscopy. With increasing the fluorine content, the refractive indices of UV-cured films decreased. However, the UV-curing rate and final conversion was decreased with increasing contents of PFPE, which resulted in the decrease of the glass transition temperature (T(g)), crosslink density, tensile strength and surface hardness. PMID:21788027

  4. Quasi-nano wear mechanism under repeated impact contact loading

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A new quasi-nano wear mechanism (QNWM) has been proposed in this paper based on the facts of wear curve turning under high energy impact contact loading.Its characteristic is that the wear rate of QNWM is only 1/10-1/3 that of delamination mechanism at the same energy density.The diameters of wear debris and pits on the worn surfaces fall into the quasi-nanometer scale (about 50-120 nm).The necessary and sufficient conditions,which bring about the QNWM,are:(i) the nano-structure (nano-crystalline + amorphous phase) in impact contact surface layer has formed by the intensive impact strain;(ii) the delamination wear cracking in sub-surface layer must be restrained;(iii) the microcracks of QNWM are produced in amorphous phase of surface nano-structure layer rather than in nano-crystalline.

  5. Characterization of the quality of metal-graphene contact with contact end resistance measurement

    Science.gov (United States)

    Wang, Shaoqing; Mao, Dacheng; Muhammad, Asif; Peng, Songang; Zhang, Dayong; Shi, Jingyuan; Jin, Zhi

    2016-07-01

    The quality of metal-graphene contact has a great influence on the performance of graphene-based electronic devices. In this paper, a simple, fast and accurate method is introduced to evaluate the quality of metal-graphene contact, which is based on measuring the contact end resistance. Using this method, the effect of rapid thermal annealing on the metal-graphene contact is investigated. It is common observation that before the rapid thermal annealing, contact end resistance has a large variation showing that the metal-graphene contact is in a relatively unstable state when the device is just prepared. After the rapid thermal annealing treatment, contact end resistances show a good consistency for all the devices. The results of contact end resistance are consistent with the images of scanning electron microscope observed before and after the rapid thermal annealing, which indicates that using the contact end resistance to evaluate the quality of metal-graphene contact is an efficient and effective way to predict the contact quality.

  6. Tomato contact dermatitis

    DEFF Research Database (Denmark)

    Paulsen, Evy; Christensen, Lars P; Andersen, Klaus Ejner

    2012-01-01

    The tomato plant (Solanum lycopersicum) is an important crop worldwide. Whereas immediate-type reactions to tomato fruits are well known, contact dermatitis caused by tomatoes or tomato plants is rarely reported. The aims of this study were to present new data on contact sensitization to tomato...... plants and review the literature on contact dermatitis caused by both plants and fruits. An ether extract of tomato plants made as the original oleoresin plant extracts, was used in aimed patch testing, and between 2005 and 2011. 8 of 93 patients (9%) tested positive to the oleoresin extracts....... This prevalence is in accordance with the older literature that reports tomato plants as occasional sensitizers. The same applies to tomato fruits, which, in addition, may cause protein contact dermatitis. The allergens of the plant are unknown, but both heat-stable and heat-labile constituents seem...

  7. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... also available in Spanish . Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical ...

  8. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology ...

  9. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... had not been properly fitted by an eye care professional, the lenses stuck to my eye like ... lenses do not require the same level of care or consideration as a standard contact lens because ...

  10. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Many of the lenses found online or in beauty salons, novelty shops or in pop-up Halloween ... in the United States. Related Stories Are six-month contact lenses purchased in Korea safe? May 13, ...

  11. Colored Contact Lens Dangers

    Science.gov (United States)

    ... Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / News Halloween Hazard: The Hidden Dangers of Buying Decorative Contact Lenses Without a Prescription Sep. 26, 2013 It started ...

  12. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Sep 10, 2015 Contact Lens Horror Stories: Poor Care Can Lead to Blindness Sep 09, 2015 How to Correct High Myopia Feb 27, 2015 More Eye Health News Pet Fish Fitted with Fake Eye in ...

  13. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... ask for a prescription. There is no such thing as a "one size fits all" contact lens. ...

  14. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... your website . Printable posters . Promotional materials for eye health observances. EyeSmart resources are also available in Spanish . Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at ...

  15. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Many of the lenses found online or in beauty salons, novelty shops or in pop-up Halloween ... Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical ...

  16. Harmonic almost contact structures

    OpenAIRE

    Vergara-Diaz, E.; Wood, C. M.

    2006-01-01

    An almost contact metric structure is parametrized by a section of an associated homogeneous fibre bundle, and conditions for this to be a harmonic section, and a harmonic map, are studied. These involve the characteristic vector field, and the almost complex structure in the contact subbundle. Several examples are given where the harmonic section equations reduce to those for the characteristic field to be a harmonic section of the unit tangent bundle. These include trans-Sasakian structures...

  17. Lettuce contact allergy

    DEFF Research Database (Denmark)

    Paulsen, Evy; Andersen, Klaus E

    2016-01-01

    Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present...... person who is occupationally exposed to lettuce for longer periods, especially atopics, amateur gardeners, and persons keeping lettuce-eating pets, is potentially at risk of developing lettuce contact allergy....

  18. Data Qualification Report: Borehole Straigraphic Contacts

    Energy Technology Data Exchange (ETDEWEB)

    R.W. Clayton; C. Lum

    2000-04-18

    The data set considered here is the borehole stratigraphic contacts data (DTN: M09811MWDGFM03.000) used as input to the Geologic Framework Model. A Technical Assessment method used to evaluate these data with a two-fold approach: (1) comparison to the geophysical logs on which the contacts were, in part, based; and (2) evaluation of the data by mapping individual units using the entire data set. Qualification of the geophysical logs is being performed in a separate activity. A representative subset of the contacts data was chosen based on importance of the contact and representativeness of that contact in the total data set. An acceptance window was established for each contact based on the needs of the data users. Data determined to be within the acceptance window were determined to be adequate for their intended use in three-dimensional spatial modeling and were recommended to be Qualified. These methods were chosen to provide a two-pronged evaluation that examines both the origin and results of the data. The result of this evaluation is a recommendation to qualify all contacts. No data were found to lie outside the pre-determined acceptance window. Where no geophysical logs are available, data were evaluated in relation to surrounding data and by impact assessment. These data are also recommended to be qualified. The stratigraphic contact data contained in this report (Attachment VII; DTN: M00004QGFMPICK.000) are intended to replace the source data, which will remain unqualified.

  19. Lettuce contact allergy.

    Science.gov (United States)

    Paulsen, Evy; Andersen, Klaus E

    2016-02-01

    Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present new data on lettuce contact allergy and review the literature. Lettuce is weakly allergenic, and occupational cases are mainly reported. Using aimed patch testing in Compositae-allergic patients, two recent Danish studies showed prevalence rates of positive lettuce reactions of 11% and 22%. The majority of cases are non-occupational, and may partly be caused by cross-reactivity. The sesquiterpene lactone mix seems to be a poor screening agent for lettuce contact allergy, as the prevalence of positive reactions is significantly higher in non-occupationally sensitized patients. Because of the easy degradability of lettuce allergens, it is recommended to patch test with freshly cut lettuce stem and supplement this with Compositae mix. As contact urticaria and protein contact dermatitis may present as dermatitis, it is important to perform prick-to-prick tests, and possibly scratch patch tests as well. Any person who is occupationally exposed to lettuce for longer periods, especially atopics, amateur gardeners, and persons keeping lettuce-eating pets, is potentially at risk of developing lettuce contact allergy. PMID:26289653

  20. THE ENERGY ISSUES: A CORPUS-BASED ANALYSIS

    Directory of Open Access Journals (Sweden)

    Maria-Floriana Popescu

    2015-06-01

    Full Text Available The energy-related issues have become of paramount importance in recent years due to the exhaustion of fossil fuel resources, their price variations and political dependence on nations with role of energy providers. In addition, the changing in climate conditions requires reduction emissions of greenhouse gases. Therefore, this paper proposes and assesses the novel idea of using constructions as a unit of analysis for corpus-based discourse analysis in the energy field. This article will use a standard method in linguistics to quantitatively investigate academic writings from both a lexical and a stylistic perspective. The present research paper aims to add to the knowledge about energy issues by conducting a data-driven analysis of economic academic discourse, through three periods of time and using secondary data analysis. The findings suggest the evolution of the energy sector throughout time and they gave interesting and different insights into the content of the discourses and enabled better comparison of corpora.