WorldWideScience

Sample records for flexible micro air

  1. Flexible Wing Base Micro Aerial Vehicles: Micro Air Vehicles (MAVs) for Surveillance and Remote Sensor Delivery

    Science.gov (United States)

    Ifju, Peter

    2002-01-01

    Micro Air Vehicles (MAVs) will be developed for tracking individuals, locating terrorist threats, and delivering remote sensors, for surveillance and chemical/biological agent detection. The tasks are: (1) Develop robust MAV platform capable of carrying sensor payload. (2) Develop fully autonomous capabilities for delivery of sensors to remote and distant locations. The current capabilities and accomplishments are: (1) Operational electric (inaudible) 6-inch MAVs with novel flexible wing, providing superior aerodynamic efficiency and control. (2) Vision-based flight stability and control (from on-board cameras).

  2. Sound absorption of a finite flexible micro-perforated panel backed by an air cavity

    Science.gov (United States)

    Lee, Y. Y.; Lee, E. W. M.; Ng, C. F.

    2005-10-01

    Micro-perforated absorbers have been studied for decades. In the experimental results of some previous works, an unexpected peak due to the flexible panel vibration effect was found on the absorption coefficient curve. In this paper, the acoustic absorption of a finite flexible micro-perforated panel backed by an air cavity is studied in detail. The absorption formula that is developed for the micro-perforated absorber is based on the modal analysis solution of the classical plate equation coupled with the acoustic wave equation. Another approach to derive a simpler absorption formula is also developed. The predictions from the two formulas are very close, except for those at the resonant frequencies of the higher structural modes and acoustic modes parallel to the panel surface. The theoretical results show good agreement with the measurements. It can be concluded that (1) as the panel vibration effect can dissipate more energy, the corresponding absorption peaks can widen the absorption bandwidth of a micro-perforated absorber by appropriately selecting the parameters such as panel thickness, perforation diameter, and perforation spacing, etc., such that the structural resonant frequency is higher than the absorption peak frequency caused by the perforations; (2) the comparison of the cases of different panel mode shapes does not show a significant difference in the absorption performance; and (3) the structural damping effect can improve the absorption performance at the frequencies between the structural resonant frequencies and the peak frequency of the micro-perforation effect, and decrease the peak absorption values of the structural resonances.

  3. Aerodynamics of a bio-inspired flexible flapping-wing micro air vehicle.

    Science.gov (United States)

    Nakata, T; Liu, H; Tanaka, Y; Nishihashi, N; Wang, X; Sato, A

    2011-12-01

    MAVs (micro air vehicles) with a maximal dimension of 15 cm and nominal flight speeds of around 10 m s⁻¹, operate in a Reynolds number regime of 10⁵ or lower, in which most natural flyers including insects, bats and birds fly. Furthermore, due to their light weight and low flight speed, the MAVs' flight characteristics are substantially affected by environmental factors such as wind gust. Like natural flyers, the wing structures of MAVs are often flexible and tend to deform during flight. Consequently, the aero/fluid and structural dynamics of these flyers are closely linked to each other, making the entire flight vehicle difficult to analyze. We have recently developed a hummingbird-inspired, flapping flexible wing MAV with a weight of 2.4-3.0 g and a wingspan of 10-12 cm. In this study, we carry out an integrated study of the flexible wing aerodynamics of this flapping MAV by combining an in-house computational fluid dynamic (CFD) method and wind tunnel experiments. A CFD model that has a realistic wing planform and can mimic realistic flexible wing kinematics is established, which provides a quantitative prediction of unsteady aerodynamics of the four-winged MAV in terms of vortex and wake structures and their relationship with aerodynamic force generation. Wind tunnel experiments further confirm the effectiveness of the clap and fling mechanism employed in this bio-inspired MAV as well as the importance of the wing flexibility in designing small flapping-wing MAVs.

  4. Comprehensive modeling and control of flexible flapping wing micro air vehicles

    Science.gov (United States)

    Nogar, Stephen Michael

    Flapping wing micro air vehicles hold significant promise due to the potential for improved aerodynamic efficiency, enhanced maneuverability and hover capability compared to fixed and rotary configurations. However, significant technical challenges exist to due the lightweight, highly integrated nature of the vehicle and coupling between the actuators, flexible wings and control system. Experimental and high fidelity analysis has demonstrated that aeroelastic effects can change the effective kinematics of the wing, reducing vehicle stability. However, many control studies for flapping wing vehicles do not consider these effects, and instead validate the control strategy with simple assumptions, including rigid wings, quasi-steady aerodynamics and no consideration of actuator dynamics. A control evaluation model that includes aeroelastic effects and actuator dynamics is developed. The structural model accounts for geometrically nonlinear behavior using an implicit condensation technique and the aerodynamic loads are found using a time accurate approach that includes quasi-steady, rotational, added mass and unsteady effects. Empirically based parameters in the model are fit using data obtained from a higher fidelity solver. The aeroelastic model and its ingredients are compared to experiments and computations using models of higher fidelity, and indicate reasonable agreement. The developed control evaluation model is implemented in a previously published, baseline controller that maintains stability using an asymmetric wingbeat, known as split-cycle, along with changing the flapping frequency and wing bias. The model-based controller determines the control inputs using a cycle-averaged, linear control design model, which assumes a rigid wing and no actuator dynamics. The introduction of unaccounted for dynamics significantly degrades the ability of the controller to track a reference trajectory, and in some cases destabilizes the vehicle. This demonstrates the

  5. Flexible Wing Base Micro Aerial Vehicles: Towards Flight Autonomy: Vision-Based Horizon Detection for Micro Air Vehicles

    Science.gov (United States)

    Nechyba, Michael C.; Ettinger, Scott M.; Ifju, Peter G.; Wazak, Martin

    2002-01-01

    Recently substantial progress has been made towards design building and testifying remotely piloted Micro Air Vehicles (MAVs). This progress in overcoming the aerodynamic obstacles to flight at very small scales has, unfortunately, not been matched by similar progress in autonomous MAV flight. Thus, we propose a robust, vision-based horizon detection algorithm as the first step towards autonomous MAVs. In this paper, we first motivate the use of computer vision for the horizon detection task by examining the flight of birds (biological MAVs) and considering other practical factors. We then describe our vision-based horizon detection algorithm, which has been demonstrated at 30 Hz with over 99.9% correct horizon identification, over terrain that includes roads, buildings large and small, meadows, wooded areas, and a lake. We conclude with some sample horizon detection results and preview a companion paper, where the work discussed here forms the core of a complete autonomous flight stability system.

  6. Air/Liquid-pressure and heartbeat-driven flexible fiber nanogenerators as a micro/nano-power source or diagnostic sensor.

    Science.gov (United States)

    Li, Zetang; Wang, Zhong Lin

    2011-01-04

    We present a new approach for fabricating flexible fiber nanogenerators (FNGs) that can be used for smart shirts, flexible electronics, and medical applications. These FNGs are based on carbon fibers that are covered cylindrically by textured zinc oxide (ZnO) thin films. Once subjected to uni-compression by applying a pressure, the cylindrical ZnO thin film is under a compressive strain, resulting in a macroscopic piezopotential across its inner and exterior surfaces owing to the textured structure of the film, which is the driving force for generating an electric current in the external load. Using such a structure, an output peak voltage of 3.2 V and average current density of 0.15 μA cm(-2) are demonstrated. The FNGs rely on air pressure, so that it can work in a non-contact mode in cases of rotating tires, flowing air/liquid, and even in blood vessels. Pressure-driven FNGs added to a syringe show potential to harvest energy in blood vessels, gas pipes, and oil pipes, as long as there is a fluctuation in pressure (or turbulence). Heart-pulse driven FNGs can serve as ultrasensitive sensors for monitoring the behavior of the human heart, which may possibly be applied to medical diagnostics as sensors and measurement tools.

  7. Application of Flexible Micro Temperature Sensor in Oxidative Steam Reforming by a Methanol Micro Reformer

    Directory of Open Access Journals (Sweden)

    Yi-Man Lo

    2011-02-01

    Full Text Available Advances in fuel cell applications reflect the ability of reformers to produce hydrogen. This work presents a flexible micro temperature sensor that is fabricated based on micro-electro-mechanical systems (MEMS technology and integrated into a flat micro methanol reformer to observe the conditions inside that reformer. The micro temperature sensor has higher accuracy and sensitivity than a conventionally adopted thermocouple. Despite various micro temperature sensor applications, integrated micro reformers are still relatively new. This work proposes a novel method for integrating micro methanol reformers and micro temperature sensors, subsequently increasing the methanol conversion rate and the hydrogen production rate by varying the fuel supply rate and the water/methanol ratio. Importantly, the proposed micro temperature sensor adequately controls the interior temperature during oxidative steam reforming of methanol (OSRM, with the relevant parameters optimized as well.

  8. Flexible intramuscular micro tube electrode combining electrical and chemical interface.

    Science.gov (United States)

    Tian, Hong-Chang; Liu, Jing-Quan; Du, Jing-Cheng; Kang, Xiao-Yang; Zhang, Chuan; Yang, Bin; Chen, Xiang; Yang, Chun-Sheng

    2014-01-01

    With the rapidly developed micromachining technology, various kinds of sophisticated microelectrodes integrated with micro fluidic channels are design and fabricated for not only electrophysiological recording and stimulation, but also chemical drug delivery. As many efforts have been devoted to develop rigid microprobes for neural research of brain, few researchers concentrate on fabrication of flexible microelectrodes for intramuscular electrophysiology and chemical interfacing. Since crude wire electrodes still prevail in functional electrical stimulation (FES) and electromyography (EMG) recording of muscle, here we introduce a flexible micro tube electrode combining electrical and chemical pathway. The proposed micro tube electrode is manufactured based on polymer capillary, which provide circumferential electrode site contacting with electro-active tissue and is easy to manufactured with low cost.

  9. Flexible strain sensor for air muscles using polypyrrole coated rubber

    Science.gov (United States)

    Tjahyono, Arief P.; Aw, Kean C.; Travas-Sejdic, Jadranka; Li, K. C.

    2010-04-01

    A novel flexible large strain sensor was developed to be use with an air muscle. A piece of butyl rubber was coated with the conducting polymer, polypyrrole through bulk solution and chemical vapour deposition method. The strain sensor was able to response to sudden movements represented by the multiple step functions of the applied strain. Consistency of the sensor's output was studied and the average error in the change of resistance was calculated to be 0.32% and 0.72% for elongation and contraction respectively for the sample made using chemical vapour deposition. However, a hysteresis was observed for this sample for a single cycle of elongation and contraction with the highest error calculated to be 3.2% at a 0% applied strain. SEM images showed the propagation of surface micro-cracks as the cause of the variation in surface resistance with applied strain. In addition, slower relaxation rate of the rubber prevented the surface micro-cracks to open and close at the same rate. The idea of utilizing conducting polymer coating can be applied to the inner rubber tube of the air muscle. As such, a complete integration between actuator and sensor can be realized.

  10. Projection moire interferometry measurements of micro air vehicle wings

    Science.gov (United States)

    Fleming, Gary A.; Bartram, Scott M.; Waszak, Martin R.; Jenkins, Luther N.

    2001-11-01

    Projection Moire Interferometry (PMI) has been used to measure the structural deformation of micro air vehicle (MAV) wings during a series of wind tunnel tests. The MAV wings had a highly flexible wing structure, generically reminiscent of a bat's wing, which resulted in significant changes in wing shape as a function of MAV angle-of-attack and simulated flight speed. This flow-adaptable wing deformation is thought to provide enhanced vehicle stability and wind gust alleviation compared to rigid wing designs. Investigation of the potential aerodynamic benefits of a flexible MAV wing required measurement of the wing shape under aerodynamic loads. PMI was used to quantify the aerodynamically induced changes in wing shape for three MAV wings having different structural designs and stiffness characteristics. This paper describes the PMI technique, its application to MAV testing, and presents a portion of the PMI data acquired for the three different MAV wings tested.

  11. MICRO ELECTRICAL DISCHARGE MACHINING DEPOSITION IN AIR

    Institute of Scientific and Technical Information of China (English)

    JIN Baidong; ZHAO Wansheng; WANG Zhenlong; CAO Guohui

    2006-01-01

    A new deposition method is described using micro electrical discharge machining (EDM)to deposit tool electrode material on workpiece in air. The basic principles of micro electrical discharge deposition (EDD) are analyzed and the realized conditions are predicted. With an ordinary EDM shaping machine, brass as the electrode, high-speed steel as the workpiece, a lot of experiments are carried out on micro EDD systematically and thoroughly. The effects of major processing parameters, such as the discharge current, discharge duration, pulse interval and working medium, are obtained. As a result, a micro cylinder with 0.19 mm in diameter and 7.35 mm in height is deposited.By exchanging the polarities of the electrode and workpiece the micro cylinder can be removed selectively. So the reversible machining of deposition and removal is achieved, which breaks through the constraint of traditional EDM. Measurements show that the deposited material is compact and close to workpiece base, whose components depend on the tool electrode material.

  12. Towards Flexible Self-powered Micro-scale Integrated Systems

    KAUST Repository

    Rojas, Jhonathan Prieto

    2014-04-01

    Today’s information-centered world leads the ever-increasing consumer demand for more powerful, multifunctional portable devices. Additionally, recent developments on long-lasting energy sources and compliant, flexible systems, have introduced new required features to the portable devices industry. For example, wireless sensor networks are in urgent need of self-sustainable, easy-to-deploy, mobile platforms, wirelessly interconnected and accessible through a cloud computing system. The objective of my doctoral work is to develop integration strategies to effectively fabricate mechanically flexible, energy-independent systems, which could empower sensor networks for a great variety of new exciting applications. The first module, flexible electronics, can be achieved through several techniques and materials. Our main focus is to bring mechanical flexibility to the state-of-the-art high performing silicon-based electronics, with billions of ultra-low power, nano-sized transistors. Therefore, we have developed a low-cost batch fabrication process to transform standard, rigid, mono-crystalline silicon (100) wafer with devices, into a thin (5-20 m), mechanically flexible, optically semi-transparent silicon fabric. Recycling of the remaining wafer is possible, enabling generation of multiple fabrics to ensure lowcost and optimal utilization of the whole substrate. We have shown mono, amorphous and poly-crystalline silicon and silicon dioxide fabrics, featuring industry’s most advanced high-/metal-gate based capacitors and transistors. The second module consists on the development of efficient energy scavenging systems. First, we have identified an innovative and relatively young technology, which can address at the same time two of the main concerns of human kind: water and energy. Microbial fuel cells (MFC) are capable of producing energy out the metabolism of bacteria while treating wastewater. We have developed two micro-liter MFC designs, one with carbon

  13. Model Identification of a Micro Air Vehicle

    Institute of Scientific and Technical Information of China (English)

    Jorge Ni(n)o; Flavius Mitrache; Peter Cosyn; Robin De Keyser

    2007-01-01

    This paper is focused on the model identification of a Micro Air Vehicle (MAV) in straight steady flight condition. The identification is based on input-output data collected from flight tests using both frequency and time dontain techniques. The vehicle is an in-house 40 cm wingspan airplane. Because of the complex coupled, multivariable and nonlinear dynamics of the aircraft, linear SISO structures for both the lateral and longitudinal models around a reference state were derived. The aim of the identification is to provide models that can be used in future development of control techniques for the MAV.

  14. A flexible micro fluid transport system featuring magnetorheological elastomer

    Science.gov (United States)

    Behrooz, Majid; Gordaninejad, Faramarz

    2016-02-01

    This study presents a flexible magnetically-actuated micro fluid transport system utilizing an isotropic magnetorheological elastomer (MRE). Theoretical modeling and analysis of this system is presented for a two-dimensional model. This fluid transport system can propel the fluid by applying a fluctuating magnetic field on the MRE. The magneto-fluid-structure interaction analysis is employed to determine movement of the solid domain and the velocity of the fluid under a controllable magnetic field. The effects of key material, geometric, and magnetic parameters on the behavior of this system are examined. It is demonstrated that the proposed system can propel the fluid unidirectionally, and the volume of the transported fluid is significantly affected by some of the design parameters.

  15. Flexible electrode and its characteristics for micro actuator

    Science.gov (United States)

    Jung, Youngdae; Jeong, Haedo; Jeong, Eunsoo; Park, Hansu; Jo, Namju

    2002-11-01

    Flexible electrode is essential for longitudinal or traverse type of micro-actuator using electrostrictive(ES) polymer. In this paper, two types of flexible electrode using conductive polymer(CP), carbon black composite and polypyrrole(PPy), was developed for a membrane type and unimorph type ES actuator using PU. At first, electrode using carbon black powder mixed with water-dispersed polyurethane was made and its displacement and dynamic characteristics were measured and compared with commercial conductive grease. Water-dispersed PU was produced by modified acetone process, using methylethylketone and acetone as solvent via NCO-terminated prepolymer. PU actuator was manufactured by stacking carbon black electrode(CBE) at both sides of half cured PU film with spin coater. Compared with conductive grease, displacement using carbon black electrode is approximately 60%. It can be thought that CBE has considerably more viscosity and less conductivity than conductive grease. Although PPy can be made from tens of nanometer to tens of micrometer thickness, phase shift occurs between PU film and PPy because of high temperature CVD process. It is estimated that high surface energy and low surface quality disturbs contacts with PU film.

  16. Investigation of air entrapment and weld line defects in micro injection moulded thermoplastic elastomer micro rings

    DEFF Research Database (Denmark)

    Hasnaes, F.B.; Tosello, Guido; Calaon, Matteo;

    2015-01-01

    The micro injection moulding (μIM) process for the production of micro rings in thermoplastic elastomers (TPE) was investigated and optimized. The objective was to minimize the formation of air entrapments and the depth of micro weld line created on the surface of the TPE micro moulded rings...

  17. Fabrication, characterization and applications of flexible vertical InGaN micro-light emitting diode arrays.

    Science.gov (United States)

    Tian, Pengfei; McKendry, Jonathan J D; Gu, Erdan; Chen, Zhizhong; Sun, Yongjian; Zhang, Guoyi; Dawson, Martin D; Liu, Ran

    2016-01-11

    Flexible vertical InGaN micro-light emitting diode (micro-LED) arrays have been fabricated and characterized for potential applications in flexible micro-displays and visible light communication. The LED epitaxial layers were transferred from initial sapphire substrates to flexible AuSn substrates by metal bonding and laser lift off techniques. The current versus voltage characteristics of flexible micro-LEDs degraded after bending the devices, but the electroluminescence spectra show little shift even under a very small bending radius 3 mm. The high thermal conductivity of flexible metal substrates enables high thermal saturation current density and high light output power of the flexible micro-LEDs, benefiting the potential applications in flexible high-brightness micro-displays and high-speed visible light communication. We have achieved ~40 MHz modulation bandwidth and 120 Mbit/s data transmission speed for a typical flexible micro-LED.

  18. Thin-film silicon for flexible metal-air batteries.

    Science.gov (United States)

    Garamoun, Ahmed; Schubert, Markus B; Werner, Jürgen H

    2014-12-01

    Due to its high energy density, theoretical studies propose silicon as a promising candidate material for metal-air batteries. Herein, for the first time, experimental results detail the use of n-type doped amorphous silicon and silicon carbide as fuel in Si-air batteries. Thin-film silicon is particularly interesting for flexible and rolled batteries with high specific energies. Our Si-air batteries exhibit a specific capacity of 269 Ah kg(-1) and an average cell voltage of 0.85 V at a discharge current density of 7.9 μA cm(-2) , corresponding to a specific energy of 229 Wh kg(-1) . Favorably in terms of safety, low concentrated alkaline solution serves as electrolyte. Discharging of the Si-air cells continues as long as there is silicon available for oxidation.

  19. Task Space Division and Trajectory Planning for a Flexible Macro-Micro Manipulator System

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper deals with a flexible macro-micro manipulator system, which includes a long flexible manipulator and a relatively short rigid manipulator attached to the tip of the macro manipulator. A flexible macro manipulator possesses the advantages of wide operating range, high speed, and low energy consumption, but the disadvantage of a low tracking precision. The macro-micro manipulator system improves tracking performance by compensating for the endpoint tracking error while maintaining the advantages of the flexible macro manipulator. A trajectory planning scheme was built utilizing the task space division method. The division point is chosen to optimize the error compensation and energy consumption for the whole system. Then movements of the macro-micro manipulator can be determined using separate inverse kinematic models. Simulation results for a planar 4-DOF macro-micro manipulator system are presented to show the effectiveness of the control system.

  20. Death by a Thousand Cuts: Micro-Air Vehicles (MAV) in the Service of Air Force Missions

    Science.gov (United States)

    2001-04-01

    exotic approaches as air suction/injection along the wing surface (which might require micro -valves and micro - pumps ), wall heat transfer, or...AU/AWC/___/2001-4 AIR WAR COLLEGE AIR UNIVERSITY DEATH BY A THOUSAND CUTS: MICRO -AIR VEHICLES (MAV) IN THE SERVICE OF AIR FORCE MISSIONS by...Dates Covered (from... to) - Title and Subtitle Death by a thousand Cuts: Micro -Air Vehicles (MAV) in the Service of Air Force Missions Contract

  1. Financial Flexibility as a Phenomenon of Manifestation of Flexibility of the Financial System at the Micro-level

    Directory of Open Access Journals (Sweden)

    Laktionova Oleksandra A.

    2014-03-01

    Full Text Available The article considers financial flexibility of economic subjects in the context of specific features of manifestation of this property at the micro-level of the financial system. It generalises various theoretical approaches to understanding the essence of the financial flexibility in the context of motives of its formation, sources and instruments of realisation. It specifies criteria of financial flexibility: manoeuvrability, efficiency and economy. It studies interrelation between the financial flexibility and financial restrictions at the micro-level and, consequently, factors that determine them: capital market imperfection, development level and structure of the financial system, cyclicity of economy, and company characteristics (including financial architecture. The article describes their distinguishing features. It states that apart from maintaining the financial flexibility during formation of money reserves and debt load resource the companies can be guided by other motives. It offers classification of types of financial flexibility based on the sources and goals of formation, influence upon the financial potential, stages of reproduction of financial resources, the instruments used, engaged elements of the financial mechanism, stages of the business cycle and types of the used financial resources.

  2. Design and Control of Flapping Wing Micro Air Vehicles

    Science.gov (United States)

    2011-09-01

    Bar-Cohen, Y., Electroactive Polymer Actuators as Artificial Muscles: Reality, Potential and Challenges, International Society for Optical Engineering ...In 2004 he was assigned to the Air Force Academy where he taught courses in structures, dynamics, mechatronics and engineering design while...WING MICRO AIR VEHICLES DISSERTATION Presented to the Faculty Department of Aeronautics and Astronautics Graduate School of Engineering and

  3. Mapping brain activity with flexible graphene micro-transistors

    CERN Document Server

    Blaschke, Benno M; Guimerà-Brunet, Anton; Weinert, Julia; Rousseau, Lionel; Heimann, Axel; Drieschner, Simon; Kempski, Oliver; Villa, Rosa; Sanchez-Vives, Maria V; Garrido, Jose A

    2016-01-01

    Establishing a reliable communication interface between the brain and electronic devices is of paramount importance for exploiting the full potential of neural prostheses. Current microelectrode technologies for recording electrical activity, however, evidence important shortcomings, e.g. challenging high density integration. Solution-gated field-effect transistors (SGFETs), on the other hand, could overcome these shortcomings if a suitable transistor material were available. Graphene is particularly attractive due to its biocompatibility, chemical stability, flexibility, low intrinsic electronic noise and high charge carrier mobilities. Here, we report on the use of an array of flexible graphene SGFETs for recording spontaneous slow waves, as well as visually evoked and also pre-epileptic activity in vivo in rats. The flexible array of graphene SGFETs allows mapping brain electrical activity with excellent signal-to-noise ratio (SNR), suggesting that this technology could lay the foundation for a future gene...

  4. Mapping brain activity with flexible graphene micro-transistors

    Science.gov (United States)

    Blaschke, Benno M.; Tort-Colet, Núria; Guimerà-Brunet, Anton; Weinert, Julia; Rousseau, Lionel; Heimann, Axel; Drieschner, Simon; Kempski, Oliver; Villa, Rosa; Sanchez-Vives, Maria V.; Garrido, Jose A.

    2017-06-01

    Establishing a reliable communication interface between the brain and electronic devices is of paramount importance for exploiting the full potential of neural prostheses. Current microelectrode technologies for recording electrical activity, however, evidence important shortcomings, e.g. challenging high density integration. Solution-gated field-effect transistors (SGFETs), on the other hand, could overcome these shortcomings if a suitable transistor material were available. Graphene is particularly attractive due to its biocompatibility, chemical stability, flexibility, low intrinsic electronic noise and high charge carrier mobilities. Here, we report on the use of an array of flexible graphene SGFETs for recording spontaneous slow waves, as well as visually evoked and also pre-epileptic activity in vivo in rats. The flexible array of graphene SGFETs allows mapping brain electrical activity with excellent signal-to-noise ratio (SNR), suggesting that this technology could lay the foundation for a future generation of in vivo recording implants.

  5. Design and analysis of a gyroscopically controlled micro air vehicle

    Science.gov (United States)

    Thorne, Christopher Everett

    Much of the current research on micro air vehicle design relies on aerodynamic forces for attitude control. The aerodynamic environment in which micro air vehicles operate is characterized by a low Reynolds number and is not fully understood, resulting in decreased performance and efficiency when compared to large-scale vehicles. In this work, we propose a new rotary-wing micro air vehicle design that utilizes gyroscopic dynamics for attitude control. Unlike traditional micro air vehicles where attitude control moments are generated by aerodynamic control surfaces, the proposed vehicle will leverage the existing angular momentum of its rotating components to generate gyroscopic moments for controlling attitude. We explore this paradigm in an effort to reduce mechanical complexity that is inherent in blade pitch modulation mechanisms such as the swashplate, and to increase agility and possibly even efficiency when compared to state-of-the-art micro vertical-take-off-and-landing vehicles. The evolution of the mechanical design, including the evaluation of three prototypes that explore the use of gyroscopic attitude control, is presented along with a comprehensive dynamic and aerodynamic model of the third prototype. Two controllers that utilize gyroscopic moments are developed and tested in simulation. In addition, several experiments were performed using a VICON motion tracking system and off-board control. These results will also be presented.

  6. Design, Fabrication and Testing Of Flapping Wing Micro Air Vehicle

    Directory of Open Access Journals (Sweden)

    K. P. Preethi Manohari Sai

    2016-01-01

    Full Text Available Flapping flight has the potential to revolutionize micro air vehicles (MAVs due to increased aerodynamic performance, improved maneuverability and hover capabilities. The purpose of this project is to design and fabrication of flapping wing micro air vehicle. The designed MAV will have a wing span of 40cm. The drive mechanism will be a gear mechanism to drive the flapping wing MAV, along with one actuator. Initially, a preliminary design of flapping wing MAV is drawn and necessary calculation for the lift calculation has been done. Later a CAD model is drawn in CATIA V5 software. Finally we tested by Flying.

  7. Wave intensity analysis in air-filled flexible vessels.

    Science.gov (United States)

    Clavica, Francesco; Parker, Kim H; Khir, Ashraf W

    2015-02-26

    Wave intensity analysis (WIA) is an analytical technique generally used to investigate the propagation of waves in the cardiovascular system. Despite its increasing usage in the cardiovascular system, to our knowledge WIA has never been applied to the respiratory system. Given the analogies between arteries and airways (i.e. fluid flow in flexible vessels), the aim of this work is to test the applicability of WIA with gas flow instead of liquid flow. The models employed in this study are similar to earlier studies used for arterial investigations. Simultaneous pressure (P) and velocity (U) measurements were initially made in a single tube and then in several flexible tubes connected in series. Wave speed was calculated using the foot-to-foot method (cf), which was used to separate analytically the measured P and U waveforms into their forward and backward components. Further, the data were used to calculate wave intensity, which was also separated into its forward and backward components. Although the measured wave speed was relatively high, the results showed that the onsets and the nature of reflections (compression/expansion) derived with WIA, corresponded well to those anticipated using the theory of waves in liquid-filled elastic tubes. On average the difference between the experimental and theoretical arrival time of reflection was 6.1% and 3.6% for the single vessel and multivessel experiment, respectively. The results suggest that WIA can provide relatively accurate information on reflections in air-filled flexible tubes, warranting further studies to explore the full potential of this technique in the respiratory system. Copyright © 2015. Published by Elsevier Ltd.

  8. Wafer-scale integrated micro-supercapacitors on an ultrathin and highly flexible biomedical platform.

    Science.gov (United States)

    Maeng, Jimin; Meng, Chuizhou; Irazoqui, Pedro P

    2015-02-01

    We present wafer-scale integrated micro-supercapacitors on an ultrathin and highly flexible parylene platform, as progress toward sustainably powering biomedical microsystems suitable for implantable and wearable applications. All-solid-state, low-profile (RF) rectifying circuit is achieved on a single parylene platform, yielding a complete RF energy harvesting microsystem. The system discharging rate is shown to improve by ~17 times in the presence of the integrated micro-supercapacitors. This result suggests that the integrated micro-supercapacitor technology described herein is a promising strategy for sustainably powering biomedical microsystems dedicated to implantable and wearable applications.

  9. All-solid-state cable-type flexible zinc-air battery.

    Science.gov (United States)

    Park, Joohyuk; Park, Minjoon; Nam, Gyutae; Lee, Jang-soo; Cho, Jaephil

    2015-02-25

    A cable-type flexible Zn-air battery with a spiral zinc anode, gel polymer electrolyte (GPE), and air cathode coated on a nonprecious metal catalyst is designed in order to extend its application area toward wearable electronic devices.

  10. Air Flow and Gassing Potential in Micro-injection Moulding

    DEFF Research Database (Denmark)

    Griffithsa, C.A.; Dimova, S.S.; Scholz, S.

    2011-01-01

    Process monitoring of micro injection moulding (μ-IM) is of crucial importance in understanding the effects of different parameter settings on the process, especially on its performance and consistency in regards to parts’ quality. Quality factors related to mould cavity air evacuation can provide...... valuable information about the process dynamics and also about the filling of a cavity by a polymer melt. In this paper, a novel experimental set-up is proposed to monitor maximum air flow and air flow work as an integral of the air flow over time by employing a MEMS gas sensor mounted inside the mould....... The influence of four μIM parameters, melt temperature, mould temperature, injection speed, and resistance to air evacuation, on two air flow-related output parameters is investigated by carrying out a design of experiment study. The results provide empirical evidence about the effects of process parameters...

  11. Design and fabrication of a micro zinc/air battery

    Science.gov (United States)

    Fu, L.; Luo, J. K.; Huber, J. E.; Lu, T. J.

    2006-04-01

    Micro-batteries are one of the key components that restrict the application of autonomous Microsystems. However little efforts were made to solve the problem. We have proposed a new planar zinc/air micro-battery, suitable for autonomous microsystem applications. The micro-battery has a layered structure of zinc electrode/alkaline electrolyte/air cathode. A 3D zinc electrode with a high density of posts was designed to obtain a high porosity, hence to offer a best performance. A model of the micro-battery is developed and the device performances were simulated and discussed. A four-mask process was developed to fabricate the prototype micro-batteries. The preliminary testing results showed the micro-batteries is able to deliver a maximum power up to 5 mW, and with an average power of 100 µW at a steady period for up to 2hrs. Fabrication process is still under optimization for further improvement.

  12. Flapping Wing Micro Air Vehicle Wing Manufacture and Force Testing

    Science.gov (United States)

    2011-03-03

    mechanism to mimic the thorax is only half the challenge when creating mechanical fliers. Although these devices can provide some precise articulation ...Aerodynamics and Kinematics of Nature’s Micro Air Vehicles ...........................6  2.2 Mechanizing the Thorax ...Figure 3: Compression and Expansion of an Insect’s Thorax .......................................... 12  Figure 4: University of Florida Flapping 1 DOF

  13. In Situ Monitoring of Temperature inside Lithium-Ion Batteries by Flexible Micro Temperature Sensors

    Directory of Open Access Journals (Sweden)

    Pei-Chi Chen

    2011-10-01

    Full Text Available Lithium-ion secondary batteries are commonly used in electric vehicles, smart phones, personal digital assistants (PDA, notebooks and electric cars. These lithium-ion secondary batteries must charge and discharge rapidly, causing the interior temperature to rise quickly, raising a safety issue. Over-charging results in an unstable voltage and current, causing potential safety problems, such as thermal runaways and explosions. Thus, a micro flexible temperature sensor for the in in-situ monitoring of temperature inside a lithium-ion secondary battery must be developed. In this work, flexible micro temperature sensors were integrated into a lithium-ion secondary battery using the micro-electro-mechanical systems (MEMS process for monitoring temperature in situ.

  14. In situ monitoring of temperature inside lithium-ion batteries by flexible micro temperature sensors.

    Science.gov (United States)

    Lee, Chi-Yuan; Lee, Shuo-Jen; Tang, Ming-Shao; Chen, Pei-Chi

    2011-01-01

    Lithium-ion secondary batteries are commonly used in electric vehicles, smart phones, personal digital assistants (PDA), notebooks and electric cars. These lithium-ion secondary batteries must charge and discharge rapidly, causing the interior temperature to rise quickly, raising a safety issue. Over-charging results in an unstable voltage and current, causing potential safety problems, such as thermal runaways and explosions. Thus, a micro flexible temperature sensor for the in in-situ monitoring of temperature inside a lithium-ion secondary battery must be developed. In this work, flexible micro temperature sensors were integrated into a lithium-ion secondary battery using the micro-electro-mechanical systems (MEMS) process for monitoring temperature in situ.

  15. All-inkjet-printed flexible ZnO micro photodetector for a wearable UV monitoring device

    Science.gov (United States)

    Tran, Van-Thai; Wei, Yuefan; Yang, Hongyi; Zhan, Zhaoyao; Du, Hejun

    2017-03-01

    Fabrication of small-sized patterns of inorganic semiconductor onto flexible substrates is a major concern when manufacturing wearable devices for measuring either biometric or environmental parameters. In this study, micro-sized flexible ZnO UV photodetectors have been thoroughly prepared by a facile inkjet printing technology and followed with heat treatments. A simple ink recipe of zinc acetate precursor solution was investigated. It is found that the substrate temperature during zinc precursor ink depositing has significant effects on ZnO pattern shape, film morphology, and crystallization. The device fabricated from the additive manufacturing approach has good bendability, Ohmic contact, short response time as low as 0.3 s, and high on/off ratio of 3525. We observed the sensor’s dependence of response/decay time by the illuminating UV light intensity. The whole process is based on additive manufacturing which has many benefits such as rapid prototyping, saving material, being environmentally friendly, and being capable of creating high-resolution patterns. In addition, this method can be applied to flexible substrates, which makes the device more applicable for applications requiring flexibility such as wearable devices. The proposed all-inkjet-printing approach for a micro-sized ZnO UV photodetector would significantly simplify the fabrication process of micro-sized inorganic semiconductor-based devices. A potential application is real-time monitoring of UV light exposure to warn users about unsafe direct sunlight to implement suitable avoidance solutions.

  16. Micro- and Nano-Air Vehicles: State of the Art

    Directory of Open Access Journals (Sweden)

    Luca Petricca

    2011-01-01

    Full Text Available Micro- and nano air vehicles are defined as “extremely small and ultra-lightweight air vehicle systems” with a maximum wingspan length of 15 cm and a weight less than 20 grams. Here, we provide a review of the current state of the art and identify the challenges of design and fabrication. Different configurations are evaluated, such as fixed wings, rotary wings, and flapping wings. The main advantages and drawbacks for each typology are identified and discussed. Special attention is given to rotary-wing vehicles (helicopter concept; including a review of their main structures, such as the airframe, energy storage, controls, and communications systems. In addition, a review of relevant sensors is also included. Examples of existing and future systems are also included. Micro- and nano-vehicles with rotary wings and rechargeable batteries are dominating. The flight times of current systems are typically around 1 hour or less due to the limited energy storage capabilities of the used rechargeable batteries. Fuel cells and ultra capacitors are promising alternative energy supply technologies for the future. Technology improvements, mainly based on micro- and nanotechnologies, are expected to continue in an evolutionary way to improve the capabilities of future micro- and nano air vehicles, giving improved flight times and payload capabilities.

  17. Experimental Investigations of Micro Air Injection to Control Rotating Stall

    Institute of Scientific and Technical Information of China (English)

    Chaoqun Nie; Zhiting Tong; Shaojuan Geng; Junqiang Zhu; Weiguang Huang

    2007-01-01

    Steady discrete micro air injection at the tip region in front of the first compressor rotor has been proved to be an effective method to delay the inception of rotating stall in a low speed axial compressor. Considering the practical application a new type of micro injector was designed and described in this paper, which was imbedded in the casing and could be moved along the chord. In order to verify its feasibility to other cases, such as high subsonic axial compressor or centrifugal compressor, some other cases have been studied. Experimental results of the same low speed axial compressor showed that the new injector could possess many other advantages besides successfully stabilizing the compressor. Experiments performed on a high subsonic axial compressor confirmed the effectiveness of micro air injection when the relative velocity at the blade tip is high subsonic. Meanwhile in order to explore its feasibility in centrifugal compressor, a similar micro injector was designed and tested on a low speed centrifugal compressor with vaned diffuser. The injected mass flow was a bit larger than that used in axial compressors and the results showed micro injection could also delay the onset of rotating stall in the centrifugal compressor.

  18. microRNAs: Implications for air pollution research

    Energy Technology Data Exchange (ETDEWEB)

    Jardim, Melanie J., E-mail: melaniejardim@gmail.com [Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Chapel Hill, NC (United States)

    2011-12-01

    The purpose of this review is to provide an update of the current understanding on the role of microRNAs in mediating genetic responses to air pollutants and to contemplate on how these responses ultimately control susceptibility to ambient air pollution. Morbidity and mortality attributable to air pollution continues to be a growing public health concern worldwide. Despite several studies on the health effects of ambient air pollution, underlying molecular mechanisms of susceptibility and disease remain elusive. In the last several years, special attention has been given to the role of epigenetics in mediating, not only genetic and physiological responses to certain environmental insults, but also in regulating underlying susceptibility to environmental stressors. Epigenetic mechanisms control the expression of gene products, both basally and as a response to a perturbation, without affecting the sequence of DNA itself. These mechanisms include structural regulation of the chromatin structure, such as DNA methylation and histone modifications, and post-transcriptional gene regulation, such as microRNA mediated repression of gene expression. microRNAs are small noncoding RNAs that have been quickly established as key regulators of gene expression. As such, miRNAs have been found to control several cellular processes including apoptosis, proliferation and differentiation. More recently, research has emerged suggesting that changes in the expression of some miRNAs may be critical for mediating biological, and ultimately physiological, responses to air pollutants. Although the study of microRNAs, and epigenetics as a whole, has come quite far in the field of cancer, the understanding of how these mechanisms regulate gene-environment interactions to environmental exposures in everyday life is unclear. This article does not necessarily reflect the views and policies of the US EPA.

  19. Numerical characterization of the hydrodynamics and thermal behavior of air flow in flexible air distribution system

    Science.gov (United States)

    Gharehdaghi, Samad; Moujaes, Samir

    2013-10-01

    Flexible duct air distribution systems are used in a large percentage of residential and small commercial buildings in the United States . Very few empirical or predictive data are available though to help provide the HVAC design engineer with reliable information . Moreover, because of the ducts flexibility, the shapes of these ducts offer a different set of operating fluid flow and thermal conditions from traditional smooth metal ducts. Hence, both the flow field and heat transfer through this kind of ducts are much more complex and merit to be analyzed from a numerical predictive approach. The aim of this research paper is to compute some of the hydrodynamic and heat transfer characteristics of the air flow inside these ducts over a range of Re numbers commonly used in the flow conditions of these air distribution systems. The information resulting from this CFD simulation, where a κ-ɛ turbulent model is used to predict the flow conditions, provide pressure drop and average convective heat transfer coefficients that exist in these ducts and was compared to previously found data. Circulation zones in the depressions of these ducts are found to exist which are suspected of influencing the pressured drop and heat transfer coefficients as compared to smooth ducts. The results show that fully developed conditions exist much earlier with regard to the inlet for both hydrodynamic and thermal entrance regions than what would be expected in smooth ducts under the same turbulent conditions.

  20. Flexible micro-OCT endobronchial probe for imaging of mucociliary transport (Conference Presentation)

    Science.gov (United States)

    Cui, Dongyao; Chu, Kengyeh K.; Unglert, Carolin I.; Ford, Tim N.; Carruth, Robert W.; Hyun, Daryl; Singh, Kanwarpal; Birket, Susan E.; Solomon, George M.; Rowe, Steve M.; Tearney, Guillermo J.

    2016-03-01

    Mucociliary clearance (MCC) plays a significant role in maintaining the health of human respiratory system by eliminating foreign particles trapped within mucus. Failure of this mechanism in diseases such as cystic fibrosis and chronic obstructive pulmonary disease (COPD) leads to airway blockage and lung infection, causing morbidity and mortality. The volume of airway mucus and the periciliary liquid encapsulating the cilia, in addition to ciliary beat frequency and velocity of mucociliary transport, are vital parameters of airway health. However, the diagnosis of disease pathogenesis and advances of novel therapeutics are hindered by the lack of tools for visualization of ciliary function in vivo. Our laboratory has previously developed a 1-µm resolution optical coherence tomography method, termed Micro-OCT, which is capable of visualizing mucociliary transport and quantitatively capturing epithelial functional metrics. We have also miniaturized Micro-OCT optics in a first-generation rigid 4mm Micro-OCT endoscope utilizing a common-path design and an apodizing prism configuration to produce an annular profile sample beam, and reported the first in vivo visualization of mucociliary transport in swine. We now demonstrate a flexible 2.5 mm Micro-OCT probe that can be inserted through the instrument channel of standard flexible bronchoscopes, allowing bronchoscopic navigation to smaller airways and greatly improving clinical utility. Longitudinal scanning over a field of view of more than 400 µm at a frame rate of 40 Hz was accomplished with a driveshaft transduced by a piezo-electric stack motor. We present characterization and imaging results from the flexible micro-OCT probe and progress towards clinical translation. The ability of the bronchoscope-compatible micro-OCT probe to image mucus clearance and epithelial function will enable studies of cystic fibrosis pathogenesis in small airways, provide diagnosis of mucociliary clearance disorders, and allow

  1. Flexible Micro Thermoelectric Generator based on Electroplated Bi2Te3

    CERN Document Server

    Schwyter, E; Durrer, L; Hierold, Ch

    2008-01-01

    We present and discuss the fabrication process and the performance of a flexible micro thermoelectric generator with electroplated Bi2Te3 thermocouples in a SU-8 mold. Demonstrator devices generate 278uWcm-2 at dTmeas=40K across the experimental set up. Based on model calculations, a temperature difference of dTG=21.4K across the generator is assumed. Due to the flexible design and the chosen generator materials, the performance stays high even for curved contact surfaces. The measurement results correlate well with the model based design optimization predictions.

  2. Flexible Rechargeable Zinc-Air Batteries through Morphological Emulation of Human Hair Array.

    Science.gov (United States)

    Fu, Jing; Hassan, Fathy Mohamed; Li, Jingde; Lee, Dong Un; Ghannoum, Abdul Rahman; Lui, Gregory; Hoque, Md Ariful; Chen, Zhongwei

    2016-08-01

    An electrically rechargeable, nanoarchitectured air electrode that morphologically emulates a human hair array is demonstrated in a zinc-air battery. The hair-like array of mesoporous cobalt oxide nanopetals in nitrogen-doped carbon nanotubes is grown directly on a stainless-steel mesh. This electrode produces both flexibility and improved battery performance, and thus fully manifests the advantages of flexible rechargeable zinc-air batteries in practical applications.

  3. Electrohydrodynamic Direct-Write Orderly Micro/Nanofibrous Structure on Flexible Insulating Substrate

    Directory of Open Access Journals (Sweden)

    Jiang-Yi Zheng

    2014-01-01

    Full Text Available AC pulse-modulated electrohydrodynamic direct-writing (EDW was utilized to direct-write orderly micro/nanofibrous structure on the flexible insulating polyethylene terephthalate (PET substrate. During the EDW process, AC electrical field induced charges to reciprocate along the jet and decreased the charge repulsive force that applied on charged jet. Thanks to the smaller charge repulsive force, stable straight jet can be built up to direct-write orderly micro/nanofibrous structures on the insulating substrate. The minimum motion velocity required to direct-write straight line fibrous structure on insulating PET substrate was 700 mm/s. Moreover, the influences of AC voltage amplitude, frequency, and duty cycle ratio on the line width of fibrous structures were investigated. This work proposes a novel solution to overcome the inherent charge repulsion emerging on the insulating substrate, and promotes the application of EDW technology on the flexible electronics.

  4. Modeling on thermally induced coupled micro-motions of satellite with complex flexible appendages

    Directory of Open Access Journals (Sweden)

    Zhicheng Zhou

    2015-06-01

    Full Text Available To describe the characteristics of thermally induced coupled micro-motions more exactly, a numerical model is proposed for a satellite system consisting of a rigid body and the complex appendages. The coupled governing equations including the effects of transient temperature differences are formulated within the framework of the Lagrangian Method based on the finite element models of flexible structures. Meanwhile, the problem of coupling between attitude motions of rigid body and vibrations of flexible attachments are addressed with explicit expressions. Thermally induced micro-motions are examined in detail for a simple satellite with a large solar panel under the disturbance of thermal environment from earth shadow to sunlight area in the earth orbit. The results show that the thermal–mechanical performances of an on-orbit satellite can be well predicted by the proposed finite element model.

  5. Micro-lens array design on a flexible light-emitting diode package for indoor lighting.

    Science.gov (United States)

    Lee, Hsiao-Wen; Lin, Bor-Shyh

    2015-10-01

    An advanced, ultra-thin, flexible LED (FLED) package technique is first proposed in this study, where a polyimide substrate was used as the lead frame package material due to its physical stability in thermal processing. The experimental results showed that the thickness of the mockup sample measured by a vernier caliper was 260 μm and 35% thinner than the Panasonic organic LED lighting panel announced on 4 March 2014 in Tokyo. Moreover, the flexible angle of the ultra-thin LED package was 200.54° when it surrounded a disk with a 1 cm radius. A design of a micro-lens array manufactured by silicone molding on the FLED is also proposed in this study. Finally, different types of micro-lenses were applied to different lighting regions to investigate their lighting effects.

  6. Unsteady Low Reynolds Number Aerodynamics for Micro Air Vehicles (MAVs)

    Science.gov (United States)

    2010-05-01

    horizontal model. The first has advantages of placing t he force balance above the water line and thus solving the balance waterproofing i ssues , an d h...ABSTRACT This work introduces the Micro Air Vehicle (MAV) problem from the viewpoint of aerodynamics. Water tunnels are assessed as tools for MAV...aerodynamics. The design, construction and instrumentation of RB’s “Horizontal Free-surface Water Tunnel” is documented. Experiments in steady

  7. Flisht mechanism and design of biomimetic micro air vehicles

    Institute of Scientific and Technical Information of China (English)

    ANG HaiSong; XIAO TianHang; DUAN WenBo

    2009-01-01

    This paper summaries the investigations on natural flyers and development of bio-mimetic micro air vehicles(MAVs)at NUAA,China,where the authors have led a group to conduct research for a decade.The investigations include the studies of low Reynolds number aerodynamics,unsteady computational fluid dynamics and flight control for the fixed-wing MAVs,the bird-like MAVs,the dragonfly-like MAVs and the bee-like MAVs.

  8. Flight mechanism and design of biomimetic micro air vehicles

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper summaries the investigations on natural flyers and development of bio-mimetic micro air vehicles(MAVs)at NUAA,China,where the authors have led a group to conduct research for a decade. The investigations include the studies of low Reynolds number aerodynamics,unsteady computational fluid dynamics and flight control for the fixed-wing MAVs,the bird-like MAVs,the dragonfly-like MAVs and the bee-like MAVs.

  9. A Flexible Ultrasound Transducer Array with Micro-Machined Bulk PZT

    Directory of Open Access Journals (Sweden)

    Zhe Wang

    2015-01-01

    Full Text Available This paper proposes a novel flexible piezoelectric micro-machined ultrasound transducer, which is based on PZT and a polyimide substrate. The transducer is made on the polyimide substrate and packaged with medical polydimethylsiloxane. Instead of etching the PZT ceramic, this paper proposes a method of putting diced PZT blocks into holes on the polyimide which are pre-etched. The device works in d31 mode and the electromechanical coupling factor is 22.25%. Its flexibility, good conformal contacting with skin surfaces and proper resonant frequency make the device suitable for heart imaging. The flexible packaging ultrasound transducer also has a good waterproof performance after hundreds of ultrasonic electric tests in water. It is a promising ultrasound transducer and will be an effective supplementary ultrasound imaging method in the practical applications.

  10. Experimental investigation on: Laser shock micro-forming process using the mask and flexible pad

    Science.gov (United States)

    Wang, Xiao; Li, Liyin; Shen, Zongbao; Sha, Chaofei; Gao, Shuai; Li, Cong; Sun, Xianqing; Ma, Youjuan; Liu, Huixia

    2017-01-01

    A forming process called the mask and flexible pad laser shock forming was proposed to fabricate the micro-features on the copper foil. In this process, the mask and laser beam were used as rigid punches. Shock waves induced by plasma were used as the source of loading and plasticine was used as a flexible pad. This was a micro scale and high strain rate forming process and the traditional forming method with micro-mold was changed. In the experiment, surface morphology of formed parts was represented and it was found that the mask played a significant role in the forming process. In order to understand the forming process in the experiment, process parameters, including laser pulse energy, numbers of laser pulse and grain size, were analyzed. The experimental results showed that different parameters had different effects on formed parts. The surface quality and the thickness distribution of formed parts were investigated. It was found that formed parts could keep good surface quality after laser shocking and the reasons were explored. The thickness distribution was measured and the thickness thinning rate was calculated. There was no local tightening or rupture in the forming area. In this paper, the micro-features could be obtained on metallic foils and the method of mold-free was proved to be feasible.

  11. CFD based aerodynamic modeling to study flight dynamics of a flapping wing micro air vehicle

    Science.gov (United States)

    Rege, Alok Ashok

    The demand for small unmanned air vehicles, commonly termed micro air vehicles or MAV's, is rapidly increasing. Driven by applications ranging from civil search-and-rescue missions to military surveillance missions, there is a rising level of interest and investment in better vehicle designs, and miniaturized components are enabling many rapid advances. The need to better understand fundamental aspects of flight for small vehicles has spawned a surge in high quality research in the area of micro air vehicles. These aircraft have a set of constraints which are, in many ways, considerably different from that of traditional aircraft and are often best addressed by a multidisciplinary approach. Fast-response non-linear controls, nano-structures, integrated propulsion and lift mechanisms, highly flexible structures, and low Reynolds aerodynamics are just a few of the important considerations which may be combined in the execution of MAV research. The main objective of this thesis is to derive a consistent nonlinear dynamic model to study the flight dynamics of micro air vehicles with a reasonably accurate representation of aerodynamic forces and moments. The research is divided into two sections. In the first section, derivation of the nonlinear dynamics of flapping wing micro air vehicles is presented. The flapping wing micro air vehicle (MAV) used in this research is modeled as a system of three rigid bodies: a body and two wings. The design is based on an insect called Drosophila Melanogaster, commonly known as fruit-fly. The mass and inertial effects of the wing on the body are neglected for the present work. The nonlinear dynamics is simulated with the aerodynamic data published in the open literature. The flapping frequency is used as the control input. Simulations are run for different cases of wing positions and the chosen parameters are studied for boundedness. Results show a qualitative inconsistency in boundedness for some cases, and demand a better

  12. Imaging demonstration of a flexible micro-OCT endobronchial probe (Conference Presentation)

    Science.gov (United States)

    Cui, Dongyao; Chu, Kengyeh K.; Ford, Timothy N.; Hyun, Daryl Chulho; Leung, Hui Min; Yin, Biwei; Birket, Susan E.; Solomon, George M.; Rowe, Steven M.; Tearney, Guillermo J.

    2017-04-01

    The human respiratory system is protected by a defense mechanism termed mucociliary clearance (MCC). Deficiency in MCC leads to respiratory obstruction and pulmonary infection, which often are the main causes of morbidity and mortality in diseases such as cystic fibrosis and chronic obstructive pulmonary disease (COPD). Studying key parameters that govern MCC, including ciliary beat frequency, velocity and volume of airway mucus transport, as well as periciliary liquid layer thickness are therefore of great importance in understanding human respiratory health. However, direct, in vivo visualization of ciliary function and MCC has been challenging, hindering the diagnosis of disease pathogenesis and mechanistic evaluation of novel therapeutics. Our laboratory has previously developed a 1-µm resolution optical coherence tomography method, termed Micro-OCT, which is a unique tool for visualizing the spatiotemporal features of ciliary function and MCC. We have previously described the design of a flexible 2.5 mm Micro-OCT probe that is compatible with standard flexible bronchoscopes. This device utilizes a common-path interferometer and annular sample arm apodization to attain a sharply focused spot over an extended depth of focus. Here, we present the most recent iteration of this probe and demonstrate its imaging performance in a mouse trachea tissue culture model. In addition, we have developed an ergonomic assembly for attaching the probe to a standard bronchoscope. The ergonomic assembly fixes the Micro-OCT probe's within the bronchoscope and contains a means transducing linear motion through the sheath so that the Micro-OCT beam can be scanned along the trachea. We have tested the performance of these devices for Micro-OCT imaging in an anatomically correct model of the human airway. Future studies are planned to use this technology to conduct Micro-OCT in human trachea and bronchi in vivo.

  13. Flexibility.

    Science.gov (United States)

    Humphrey, L. Dennis

    1981-01-01

    Flexibility is an important aspect of all sports and recreational activities. Flexibility can be developed and maintained by stretching exercises. Exercises designed to develop flexibility in ankle joints, knees, hips, and the lower back are presented. (JN)

  14. Design Optimization of a Micro Air Vehicle (MAV Fixed Wing

    Directory of Open Access Journals (Sweden)

    D.V.A. Rama Sastry

    2015-05-01

    Full Text Available Air vehicles are gaining attention due to their wide range of applications in civilian and defense fields. The wings of these vehicles generate a particular flow regime which is to be explored further. Since the theories on the aerodynamics of all affects are still to be investigated, simulation based computational fluid dynamics is a good approach rather than wind tunnel experiments which involves cost and long periods of experimentation. This study mainly emphasize on the lift, lift coefficient, drag and drag coefficient with respect to Reynold’s number and angle of attack, by modelling and analyzing the fixed wing of a micro air vehicle. The analysis has been done selecting NACA25411 air foil. Modelling has been done in Gambit and analysis is taken up using Fluent. Angle of attack and Reynold’s number have been optimized to increase the lift and decrease the drag.

  15. Determining aerosol particles by in-air micro-IL analysis combined with micro-PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Kada, Wataru, E-mail: kada.wataru@jaea.go.jp [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Satoh, Takahiro; Yokoyama, Akihito; Koka, Masashi; Kamiya, Tomihiro [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

    2013-07-01

    A new external ion microbeam ion luminescence (micro-IL) imaging system was developed on a microbeam line of a 3 MV single-ended accelerator at the TIARA facility of the Japan Atomic Energy Agency. Micro-IL was combined with an in-air micro-PIXE (particle-induced X-ray emission) system to determine the chemical composition and structures of microscopic airborne particles of several micrometers in size. The hardware and software for the combined in-air micro-IL analysis system, called ion luminescence microscopic imaging and spectroscopy (ILUMIS), were studied. Wavelength-dispersive optics, including a collimator lens, a monochromator, and a photon-counting photomultiplier, were installed on the beam line. The signal processing of the IL photon signals, which were collected as spectra and two-dimensional microscopic images, was examined. Several aerosol particles were characterized to demonstrate the ILUMIS/PIXE combined analysis. The external microbeam ILUMIS analysis method provided a variety of information on the chemical and elemental composition of the micrometer-sized aerosol targets under ambient atmospheric conditions.

  16. Micro and nanopatterning of functional materials on flexible plastic substrates via site-selective surface modification using oxygen plasma

    NARCIS (Netherlands)

    George, A.; Stawski, T.M.; Unnikrishnan, S.; Veldhuis, S.A.; Elshof, J.E. ten

    2012-01-01

    A simple and cost effective methodology for large area micro and nanopatterning of a wide range of functional materials on flexible substrates is presented. A hydrophobic-hydrophilic chemical contrast was patterned on surfaces of various flexible plastic substrates using molds and shadow masks with

  17. Micro and nanopatterning of functional materials on flexible plastic substrates via site-selective surface modification using oxygen plasma

    NARCIS (Netherlands)

    George, A.; Stawski, T.M.; Unnikrishnan, S.; Veldhuis, S.A.; Elshof, J.E. ten

    2012-01-01

    A simple and cost effective methodology for large area micro and nanopatterning of a wide range of functional materials on flexible substrates is presented. A hydrophobic-hydrophilic chemical contrast was patterned on surfaces of various flexible plastic substrates using molds and shadow masks with

  18. Micro- and nanopatterning of functional materials on flexible plastic substrates via site-selective surface modification using oxygen plasma

    NARCIS (Netherlands)

    George, A.; Stawski, T.M.; Unnikrishnan, S.; Veldhuis, S.A.; Elshof, ten J.E.

    2012-01-01

    A simple and cost effective methodology for large area micro and nanopatterning of a wide range of functional materials on flexible substrates is presented. A hydrophobic-hydrophilic chemical contrast was patterned on surfaces of various flexible plastic substrates using molds and shadow masks with

  19. Cerebral air embolism following transbronchial lung biopsy during flexible bronchoscopy

    Directory of Open Access Journals (Sweden)

    Matthew Evison

    2014-01-01

    Transbronchial lung biopsy may cause disruption of vessels walls within the lung parenchyma. Increased airway pressure, caused by the patient exhaling against a bronchoscope wedged within a segmental bronchi, may subsequently force air bubbles through the vessel wall defects. This may explain the occurrence of air emboli. This is a rare report of air embolism complicating transbronchial lung biopsy and all bronchoscopists should aware of this potentially fatal complication.

  20. The Preparation of Carbon Nanotube/MnO2 Composite Fiber and Its Application to Flexible Micro-Supercapacitor

    Directory of Open Access Journals (Sweden)

    Li Li

    2013-01-01

    Full Text Available In recent years, flexible electronic devices pursued for potential applications. The design and the fabrication of a novel flexible nanoarchitecture by coating electrical conductive MWCNT fiber with ultrathin films of MnO2 to achieve high specific capacitance, for micro-supercapacitors electrode applications, are demonstrated here. The MWCNT/MnO2 composite fiber electrode was prepared by the electrochemical deposition which was carried out through using two different methods: cyclic voltammetry and potentiostatic methods. The cyclic voltammetry method can get “crumpled paper ball” morphology MnO2 which has bigger specific capacitances than that achieved by potentiostatic method. The flexible micro-supercapacitor was fabricated by twisting two aligned MWCNT fibers and showed an area specific capacitance of 2.43 mF/cm2. The flexible micro-supercapacitors also enable promising applications in various fields.

  1. Optical Levitation of Micro-Scale Particles in Air

    Science.gov (United States)

    Wrbanek, Susan Y.; Weiland, Kenneth E.

    2004-01-01

    Success has been achieved using a radiation pressure gradient to levitate microscale particles in air for as long as four hours. This work is performed as a precursor to the development of a vacuum based optical tweezers interrogation tool for nanotechnology research. It was decided to first proceed with solving the problem of achieving optical levitation of a micro-scale particle in air before trying the same in a vacuum environment. This successful optical levitation in air confirms the work of Ashkin and Dziedzic. Levitation of 10 and 13.8 microns diameter polystyrene spheres was achieved, as well as the levitation of 10 and 100 microns diameter glass spheres. Particles were raised and lowered. A modicum of success was achieved translating particles horizontally. Trapping of multiple particles in one laser beam has been photographed. Also, it has been observed that particles, that may be conglomerates or irregular in shape, can also be trapped by a focused laser beam. Levitated glass beads were photographed using laser light scattered from the beads. The fact that there is evidence of optical traps in air containing irregular and conglomerate particles provides hope that future tool particles need not be perfect spheres.

  2. The Air Force Air Program and Information Management System (APIMS): A flexible tool for managing your Title V Operating Permits

    Energy Technology Data Exchange (ETDEWEB)

    Weston, A.A.; Gordon, S.R.

    1999-07-01

    The Air Force Command Core System (CCS) is an integrated, activity-based risk management system designed to support the information needs of Environment, Safety, and Occupational Health (ESOH) professionals. These professionals are responsible for managing a complex and often dynamic set of requirements, and therefore, have a need for an information system that can readily be customized to meet their specific needs. This dynamic environment also drives the need for flexibility in the system. The Air Program Information Management System (APIMS) is a module within CCS designed to not only manage permit compliance and emission inventories, but also support the monitoring, recordkeeping, and reporting requirements related to air quality issues. This paper will describe the underlying foundation of CCS, the information linkages within the database, and then summarize the functionality available within the APIMS module to support the Air Quality Managers' information needs, placing emphasis on the flexibility the system provides to manage Title V Operating Permits.

  3. Flexible High-Energy Polymer-Electrolyte-Based Rechargeable Zinc-Air Batteries.

    Science.gov (United States)

    Fu, Jing; Lee, Dong Un; Hassan, Fathy Mohamed; Yang, Lin; Bai, Zhengyu; Park, Moon Gyu; Chen, Zhongwei

    2015-10-07

    A thin-film, flexible, and rechargeable zinc-air battery having high energy density is reported particularly for emerging portable and wearable electronic applications. This freeform battery design is the first demonstrated by sandwiching a porous-gelled polymer electrolyte with a freestanding zinc film and a bifunctional catalytic electrode film. The flexibility of both the electrode films and polymer electrolyte membrane gives great freedom in tailoring the battery geometry and performance.

  4. Modeling and Analysis of an Air-Breathing Flexible Hypersonic Vehicle

    Directory of Open Access Journals (Sweden)

    Xi-bin Zhang

    2014-01-01

    Full Text Available By using light-weighted material in hypersonic vehicle, the vehicle body can be easily deformed. The mutual couplings in aerodynamics, flexible structure, and propulsion system will bring great challenges for vehicle modeling. In this work, engineering estimated method is used to calculate the aerodynamic forces, moments, and flexible modes to get the physics-based model of an air-breathing flexible hypersonic vehicle. The model, which contains flexible effects and viscous effects, can capture the physical characteristics of high-speed flight. To overcome the analytical intractability of the model, a simplified control-oriented model of the hypersonic vehicle is presented with curve fitting approximations. The control-oriented model can not only reduce the complexity of the model, but also retain aero-flexible structure-propulsion interactions of the physics-based model and can be applied for nonlinear control.

  5. Integration of an Autopilot for a Micro Air Vehicle

    Science.gov (United States)

    Platanitis, George; Shkarayev, Sergey

    2005-01-01

    Two autopilots providing autonomous flight capabilities are presented herein. The first is the Pico-Pilot, demonstrated for the 12-inch size class of micro air vehicles. The second is the MicroPilot MP2028(sup g), where its integration into a 36-inch Zagi airframe (tailless, elevons only configuration) is investigated and is the main focus of the report. Analytical methods, which include the use of the Advanced Aircraft Analysis software from DARCorp, were used to determine the stability and control derivatives, which were then validated through wind tunnel experiments. From the aerodynamic data, the linear, perturbed equations of motion from steady-state flight conditions may be cast in terms of these derivatives. Using these linear equations, transfer functions for the control and navigation systems were developed and feedback control laws based on Proportional, Integral, and Derivative (PID) control design were developed to control the aircraft. The PID gains may then be programmed into the autopilot software and uploaded to the microprocessor of the autopilot. The Pico-Pilot system was flight tested and shown to be successful in navigating a 12-inch MAV through a course defined by a number of waypoints with a high degree of accuracy, and in 20 mph winds. The system, though, showed problems with control authority in the roll and pitch motion of the aircraft: causing oscillations in these directions, but the aircraft maintained its heading while following the prescribed course. Flight tests were performed in remote control mode to evaluate handling, adjust trim, and test data logging for the Zagi with integrated MP2028(sup g). Ground testing was performed to test GPS acquisition, data logging, and control response in autonomous mode. Technical difficulties and integration limitations with the autopilot prevented fully autonomous flight from taking place, but the integration methodologies developed for this autopilot are, in general, applicable for unmanned air

  6. Strength Performance Based on Flexibility from Laterite Soil Using Tire Powder and Micro Silica

    Directory of Open Access Journals (Sweden)

    Behrouz Gordan

    2015-01-01

    Full Text Available In terms of environmental issues and human health, one of the advisable techniques to improve soil behavior is the use of scrap tires for soil structures. According to the literature, Tire-Derived Aggregates (TDA are one of the valuable materials in different field of Geotechnical that can be used. TDA properties correspond to some important factors such as high level of flexible, lightweight, high permeability and economic material comparing with sand. Strength performance based on increasing flexibility from laterite soil is the main goal of this study. For this purpose, tropical laterite soil was mixed using TDA and micro silica (MS. As a research method, unconfined tests were carried for thirteen samples based on different percentage of the additives. As a result, the significant reduction for elasticity modulus and strength was observed when soil mixed just using TDA. In addition, the rate of strain at the peak of the curve was dramatically increased. The best performance was found using 6% additives when the ratio was 3% MS and 3% TDA. In fact, the effect of MS was more to increase strength. To recommend, the seepage controlling will investigate at next.

  7. Aerodynamic Analysis of Flexible Flapping Wing Micro Aerial Vehicle Using Quasi-Steady Approach

    Science.gov (United States)

    Vijayakumar, Kolandapaiyan; Chandrasekhar, Uttam; Chandrashekhar, Nagaraj

    2016-10-01

    In recent times flexible flapping-wing aerodynamics has generated a great deal of interest and is the topic of contemporary research because of its potential application in micro aerial vehicles (MAVs). The prominent features of MAVs include low Reynolds Number, changing the camber of flapping wings, development of related mechanisms, study of the suitability airfoil shape selection and other parameters. Generally, low Reynolds Number is similar to that of an insect or a bird (103-105). The primary goal of this project work is to perform CFD analysis on flexible flapping wing MAVs in order to estimate the lift and drag by using engineering methods such as quasi-steady approach. From the wind tunnel data, 3-D deformation is obtained. For CFD analysis, two types of quasi-steady methods are considered. The first method is to slice the wing section chord-wise and span wise at multiple regions, frame by frame, and obtain the 2-D corrugated camber section for each frame. This 2-D corrugated camber is analysed using CFD techniques and all the individual 2-D corrugated camber results are summed up frame by frame, to obtain the total lift and drag for one wing beat. The second method is to consider the 3D wing in entirety and perform the CFD analysis to obtain the lift and drag for five wing beat.

  8. Research on a Micro-Grid Frequency Modulation Strategy Based on Optimal Utilization of Air Conditioners

    Directory of Open Access Journals (Sweden)

    Qingzhu Wan

    2016-12-01

    Full Text Available With the proportion of air conditioners increasing gradually, they can provide a certain amount of frequency-controlled reserves for a micro-grid. Optimizing utilization of air conditioners and considering load response characteristics and customer comfort, the frequency adjustment model is a quadratic function model between the trigger temperature of the air conditioner compressor, and frequency variation is provided, which can be used to regulate the trigger temperature of the air conditioner when the micro-grid frequency rises and falls. This frequency adjustment model combines a primary frequency modulation method and a secondary frequency modulation method of the energy storage system, in order to optimize the frequency of a micro-grid. The simulation results show that the frequency modulation strategy for air conditioners can effectively improve the frequency modulation ability of air conditioners and frequency modulation effects of a micro-grid in coordination with an energy storage system.

  9. Conducting polymer micro-supercapacitors for flexible energy storage and Ac line-filtering

    KAUST Repository

    Kurra, Narendra

    2015-04-01

    We propose a novel surfactant-mediated process to fabricate flexible microsupercapacitors (MSCs) combining conventional photolithography and electrochemical deposition. The anionic surfactant mediates the process of electropolymerisation at a lower anodic potential while causing template effects in producing porous conducting poly(3,4-ethylenedioxythiophene) (PEDOT) electrodes. Using this strategy, PEDOT MSCs with remarkable performance in terms of tunable frequency response and energy density are achieved. Specifically, ultrahigh scan rate capability up to 500V/s is achieved with a crossover frequency of 400Hz at a phase angle of -45°. This is the first polymer-based redox microsupercapacitor with excellent frequency characteristics other than carbonaceous-based electrochemical double layer capacitors reported so far in the literature. Thus, the micro-supercapacitors exhibit maximum areal cell capacitance of 9mF/cm2 with a volumetric stack capacitance of 50F/cm3 in 1M H2SO4 aqueous electrolyte. The flexibility and stability of these PEDOT MSCs is tested in aqueous gel electrolyte which showed a capacitance retention up to 80% over 10,000 cycles with a Coulombic efficiency of 100%. The maximum energy density of solid state ion gel based PEDOT MSCs was found to be 7.7mWh/cm3, which is comparable to the lithium based thin film batteries and superior to the current state-of-the-art carbon and metal oxide based MSCs. Further, the tandem configuration of flexible solid state ion gel based PEDOT MSCs is employed to demonstrate it as a power source for glowing a red light emitting diode. © 2015 Elsevier Ltd.

  10. Laser Direct Write micro-fabrication of large area electronics on flexible substrates

    Science.gov (United States)

    Zacharatos, F.; Makrygianni, M.; Geremia, R.; Biver, E.; Karnakis, D.; Leyder, S.; Puerto, D.; Delaporte, P.; Zergioti, I.

    2016-06-01

    To date, Laser Direct Write (LDW) techniques, such as Laser Induced Forward Transfer (LIFT), selective laser ablation and selective laser sintering of metal nanoparticle (NP) ink layers are receiving growing attention for the printing of uniform and well-defined conductive patterns with resolution down to 10 μm. For flexible substrates in particular, selective laser sintering of such NP patterns has been widely applied, as a low temperature and high resolution process compatible with large area electronics. In this work, LDW of silver NP inks has been carried out on polyethylene-terephthalate (PET), polyethylene-naphthalate (PEN) and polyimide (PI) substrates to achieve low electrical resistivity electrodes. In more detail, high speed short pulsed (picosecond and nanosecond) lasers with repetition rates up to 1 MHz were used to print (LIFT) metal NP inks. We thus achieved uniform and continuous patterns with a minimum feature size of 1 μm and a total footprint larger than 1 cm2. Next, the printed patterns were laser sintered with ns pulses at 532 nm over a wide laser fluence window, resulting in an electrical resistivity of 10 μΩ cm. We carried out spatial beam shaping experiments to achieve a top-hat laser intensity profile and employed selective laser ablation of thin films (thickness on the order of 100 nm) to produce silver micro-electrodes with a resolution on the order of 10 μm and a low line edge roughness. Laser sintering was combined with laser ablation to constitute a fully autonomous micro-patterning technique of metallic micro-features, with a 10 μm resolution and geometrical characteristics tuned for interdigitated electrodes for sensor applications.

  11. A flexible annular-array imaging platform for micro-ultrasound.

    Science.gov (United States)

    Qiu, Weibao; Yu, Yanyan; Chabok, Hamid Reza; Liu, Cheng; Tsang, Fu Keung; Zhou, Qifa; Shung, K Kirk; Zheng, Hairong; Sun, Lei

    2013-01-01

    Micro-ultrasound is an invaluable imaging tool for many clinical and preclinical applications requiring high resolution (approximately several tens of micrometers). Imaging systems for micro-ultrasound, including single-element imaging systems and linear-array imaging systems, have been developed extensively in recent years. Single-element systems are cheaper, but linear-array systems give much better image quality at a higher expense. Annular-array-based systems provide a third alternative, striking a balance between image quality and expense. This paper presents the development of a novel programmable and real-time annular-array imaging platform for micro-ultrasound. It supports multi-channel dynamic beamforming techniques for large-depth-of-field imaging. The major image processing algorithms were achieved by a novel field-programmable gate array technology for high speed and flexibility. Real-time imaging was achieved by fast processing algorithms and high-speed data transfer interface. The platform utilizes a printed circuit board scheme incorporating state-of-the-art electronics for compactness and cost effectiveness. Extensive tests including hardware, algorithms, wire phantom, and tissue mimicking phantom measurements were conducted to demonstrate good performance of the platform. The calculated contrast-to-noise ratio (CNR) of the tissue phantom measurements were higher than 1.2 in the range of 3.8 to 8.7 mm imaging depth. The platform supported more than 25 images per second for real-time image acquisition. The depth-of-field had about 2.5-fold improvement compared to single-element transducer imaging.

  12. Laser Direct Write micro-fabrication of large area electronics on flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zacharatos, F.; Makrygianni, M. [National Technical University of Athens, Physics Department, Zografou Campus, 15780 (Greece); Geremia, R.; Biver, E.; Karnakis, D. [Oxford Lasers Ltd, Unit 8 Moorbrook Park, Oxfordshire OX11 7HP (United Kingdom); Leyder, S.; Puerto, D.; Delaporte, P. [Aix-Marseille University, CNRS, LP3 – UMR 7341, 13288 Marseille Cedex 9 (France); Zergioti, I., E-mail: zergioti@central.ntua.gr [National Technical University of Athens, Physics Department, Zografou Campus, 15780 (Greece)

    2016-06-30

    Highlights: • Laser Direct Writing of metallic patterns with a minimum feature size of 1 μm. • Selective Laser Ablation of 50 nm thick metal films on flexible substrates. • Selective Laser sintering resulting in an electrical resistivity of 9 μΩ cm. • Laser fabrication of interdigitated electrodes for sensor applications. - Abstract: To date, Laser Direct Write (LDW) techniques, such as Laser Induced Forward Transfer (LIFT), selective laser ablation and selective laser sintering of metal nanoparticle (NP) ink layers are receiving growing attention for the printing of uniform and well-defined conductive patterns with resolution down to 10 μm. For flexible substrates in particular, selective laser sintering of such NP patterns has been widely applied, as a low temperature and high resolution process compatible with large area electronics. In this work, LDW of silver NP inks has been carried out on polyethylene-terephthalate (PET), polyethylene-naphthalate (PEN) and polyimide (PI) substrates to achieve low electrical resistivity electrodes. In more detail, high speed short pulsed (picosecond and nanosecond) lasers with repetition rates up to 1 MHz were used to print (LIFT) metal NP inks. We thus achieved uniform and continuous patterns with a minimum feature size of 1 μm and a total footprint larger than 1 cm{sup 2}. Next, the printed patterns were laser sintered with ns pulses at 532 nm over a wide laser fluence window, resulting in an electrical resistivity of 10 μΩ cm. We carried out spatial beam shaping experiments to achieve a top-hat laser intensity profile and employed selective laser ablation of thin films (thickness on the order of 100 nm) to produce silver micro-electrodes with a resolution on the order of 10 μm and a low line edge roughness. Laser sintering was combined with laser ablation to constitute a fully autonomous micro-patterning technique of metallic micro-features, with a 10 μm resolution and geometrical characteristics tuned for

  13. Fabrication and characterization of a fuel flexible micro-reformer fully integrated in silicon for micro-solid oxide fuel cell applications

    Science.gov (United States)

    Pla, D.; Salleras, M.; Garbayo, I.; Morata, A.; Sabaté, N.; Divins, N. J.; Llorca, J.; Tarancón, A.

    2015-05-01

    A novel design of a fuel-flexible micro-reactor for hydrogen generation from ethanol and methane is proposed in this work. The micro-reactor is fully fabricated with mainstream MEMS technology and consists of an array of more than 20000 through-silicon vertically aligned micro-channels per cm2 of 50 μm in diameter. Due to this unique configuration, the micro-reformer presents a total surface per projected area of 16 cm2/cm2 and per volume of 320 cm2/cm3. The active surface of the micro-reformer, i.e. the walls of the micro-channels, is homogenously coated with a thin film of Rh- Pd/CeO2 catalyst. Excellent steam reforming of ethanol and dry reforming of methane are presented with hydrogen production rates above 3 mL/min·cm2 and hydrogen selectivity of ca. 50% on a dry basis at operations conditions suitable for application in micro-solid oxide fuel cells (micro-SOFCs), i.e. 700-800ºC and fuel flows of 0.02 mLL/min for ethanol and 36 mLG/min for methane (corresponding to a system able to produce one electrical watt).

  14. Development of the NWPU20 Micro Air Vehicle

    Institute of Scientific and Technical Information of China (English)

    Li Zhanke; Song Bifeng; Zhang Yafeng; Zhang Wei; Zhang Yizhe

    2005-01-01

    This paper reports the design, construction, and operation of NWPU20 Micro Air Vehicle (MAV), which is the smallest that has, up to now, been developed in PR China. The miniaturization level in PR China makes smaller MAV, in our opinion, not possible to implement. The NWPU20 is a 20-centimeter span, battery powered, fixed-wing aircraft with an off-the-shelf color video camera that can transmit live video back to the ground station. The on-board electronic subsystems are smallest and lightest among the commercial products, including an 8-gram wireless video camera, an 8-gram receiver, a 5-gram electronic speed controller (ESC), two 4.5-gram fully proportional radio frequency control servos, and the total mass of NWPU20 is less than 80 grams. An experimental model was fabricated and tested in the Low Turbulent Flow Wind Tunnel (LTFWT) at Northwestern Polytechnical University (NWPU) to research low Reynolds number flow characteristics of the NWPU20. The result of the wind tunnel test shows that stall angle of attack of NWPU20 can reach 30°, which is higher than that of the general aircrafts, and the maximum lift-to-drag ratio of NWPU20 can nearly reach 6 at the angle of attack of 10°, which can satisfy design requirements of the NWPU20. A small-sized propulsion/torque testing system was developed to measure and analyze the propulsion and torque performances of the motor-propeller combination used in the NWPU20. A center of gravity (c.g.) testing apparatus was developed and used to adjust the c.g. of the NWPU20 so that it has good longitudinal static stability and control. The NWPU20 prototype has undergone successfully flight tests many times; it flies at 32 kilometers per hour, with an endurance of 15 minutes, and a maximum communications range of 300 meters. With the color video camera, NWPU20 successfully transmits real-time video back to the ground station. The success of NWPU20 proves preliminarily that 20-centimeter span micro air vehicle is feasible and

  15. Toluene diisocyanate emission to air and migration to a surface from a flexible polyurethane foam.

    Science.gov (United States)

    Vangronsveld, Erik; Berckmans, Steven; Spence, Mark

    2013-06-01

    Flexible polyurethane foam (FPF) is produced from the reaction of toluene diisocyanate (TDI) and polyols. Because of the potential for respiratory sensitization following exposure to TDI, concerns have been raised about potential consumer exposure to TDI from residual 'free TDI' in FPF products. Limited and conflicting results exist in the literature concerning the presence of unreacted TDI remaining in FPF as determined by various solvent extraction and analysis techniques. Because residual TDI results are most often intended for application in assessment of potential human exposure to TDI from FPF products, testing techniques that more accurately simulated human contact with foam were designed. To represent inhalation exposure to TDI from polyurethane foam, a test that measured the emission of TDI to air was conducted. For simulation of human dermal exposure to TDI from polyurethane foam, a migration test technique was designed. Emission of TDI to air was determined for a representative FPF using three different emission test cells. Two were commercially available cells that employ air flow over the surface of the foam [the Field and Laboratory Emission Cell (FLEC®) and the Micro-Chamber/Thermal Extraction™ cell]. The third emission test cell was of a custom design and features air flow through the foam sample rather than over the foam surface. Emitted TDI in the air of the test cells was trapped using glass fiber filters coated with 1-(2-methoxyphenyl)-piperazine (MP), a commonly used derivatizing agent for diisocyanates. The filters were subsequently desorbed and analyzed by liquid chromatography/mass spectrometry. Measurement of TDI migration from representative foam was accomplished by placing glass fiber filters coated with MP on the outer surfaces of a foam disk and then compressing the filters against the disk using a clamping apparatus for periods of 8 and 24 h. The sample filters were subsequently desorbed and analyzed in the same manner as for the

  16. Micro GC's for Contaminant Monitoring in Spacecraft Air Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Based on the successful separation of 20 compounds using a 1 m coated microcolumn in Phase I, we propose to design a new micro-gas chromatograph (microGC) system to...

  17. Aerial networking communication solutions using Micro Air Vehicle (MAV)

    Science.gov (United States)

    Balasubramanian, Shyam; de Graaf, Maurits; Hoekstra, Gerard; Corporaal, Henk; Wijtvliet, Mark; Cuadros Linde, Javier

    2014-10-01

    The application of a Micro Air Vehicle (MAV) for wireless networking is slowly gaining significance in the field of network robotics. Aerial transport of data requires efficient network protocols along with accurate positional adjustment of the MAV to minimize transaction times. In our proof of concept, we develop an Aerial networking protocol for data transfer using the technology of Disruption Tolerant Networks (DTN), a store-and-forward approach for environments that deals with disrupted connectivity. Our results show that close interaction between networking and flight behavior helps in efficient data exchange. Potential applications are in areas where network infrastructure is minimal or unavailable and distances may be large. For example, forwarding video recordings during search and rescue, agriculture, swarm communication, among several others. A practical implementation and validation, as described in this paper, presents the complex dynamics of wireless environments and poses new challenges that are not addressed in earlier work on this topic. Several tests are evaluated in a practical setup to display the networking MAV behavior during such an operation.

  18. Dynamics of Micro-Air-Vehicle with Flapping Wings

    Directory of Open Access Journals (Sweden)

    K. Sibilski

    2004-01-01

    Full Text Available Small (approximately 6 inch long, or hand-held reconnaissance micro air vehicles (MAVs will fly inside buildings, and require hover for observation, and agility at low speeds to move in confined spaces. For this flight envelope insect-like flapping wings seem to be an optimal mode of flying. Investigation of the aerodynamics of flapping wing MAVs is very challenging. The problem involves complex unsteady, viscous flow (mainly laminar, with the moving wing generating vortices and interacting with them. At this early stage of research only a preliminary insight into the nature of the little known aerodynamics of MAVs has been obtained. This paper describes computational models for simulation of the controlled motion of a microelectromechanical flying insect – entomopter. The design of software simulation for entomopter flight (SSEF is presented. In particular, we will estimate the flight control algorithms and performance for a Micromechanical Flying Insect (MFI, a 80–100 mm (wingtip-to-wingtip device capable of sustained autonomous flight. The SSEF is an end-to-end tool composed of several modular blocks which model the wing aerodynamics and dynamics, the body dynamics, and in the future, the environment perception, control algorithms, the actuators dynamics, and the visual and inertial sensors. We present the current state of the art of its implementation, and preliminary results. 

  19. Tunable mode-locked laser with micro-air gap cavity

    Science.gov (United States)

    Ahmad, H.; Aidit, S. N.; Hassan, N. A.; Ooi, S. I.; Tiu, Z. C.

    2017-02-01

    A tunable mode-locked laser with a micro-air gap cavity acting as a high resolution tuning is proposed and demonstrated. The laser utilizes the nonlinear polarization technique in the cavity to obtain a reliable and stable mode locking over the whole tuning range at a resolution of 1 nm. The micro-air gap is constructed by aligning two fiber facets coaxially, and the variation of micro-air gap introduces a tuning mechanism where it changes the gain saturation compensation in the gain medium and thus induces wavelength shifting on the generated solitons.

  20. Growth and characterizations of GaN micro-rods on graphene films for flexible light emitting diodes

    Directory of Open Access Journals (Sweden)

    Kunook Chung

    2014-09-01

    Full Text Available We report the growth of GaN micro-rods and coaxial quantum-well heterostructures on graphene films, together with structural and optical characterization, for applications in flexible optical devices. Graphene films were grown on Cu foil by means of chemical vapor deposition, and used as the substrates for the growth of the GaN micro-rods, which were subsequently transferred onto SiO2/Si substrates. Highly Si-doped, n-type GaN micro-rods were grown on the graphene films using metal–organic chemical vapor deposition. The growth and vertical alignment of the GaN micro-rods, which is a critical factor for the fabrication of high-performance light-emitting diodes (LEDs, were characterized using electron microscopy and X-ray diffraction. The GaN micro-rods exhibited promising photoluminescence characteristics for optoelectronic device applications, including room-temperature stimulated emission. To fabricate flexible LEDs, InxGa1–xN/GaN multiple quantum wells and a p-type GaN layer were deposited coaxially on the GaN micro-rods, and transferred onto Ag-coated polymer substrates using lift-off. Ti/Au and Ni/Au metal layers were formed to provide electrical contacts to the n-type and p-type GaN regions, respectively. The micro-rod LEDs exhibited intense emission of visible light, even after transfer onto the flexible polymer substrate, and reliable operation was achieved following numerous cycles of mechanical deformation.

  1. Air toxics and epigenetic effects: ozone altered microRNAs in the sputum of human subjects

    Science.gov (United States)

    Ozone (03) is a criteria air pollutant that is associated with numerous adverse health effects, including altered respiratory immune responses. Despite its deleterious health effects, possible epigenetic mechanisms underlying 03-induced health effects remain understudied. MicroRN...

  2. A novel graphene based nanocomposite for application in 3D flexible micro-supercapacitors

    Science.gov (United States)

    Marasso, S. L.; Rivolo, P.; Giardi, R.; Mombello, D.; Gigot, A.; Serrapede, M.; Benetto, S.; Enrico, A.; Cocuzza, M.; Tresso, E.; Pirri, C. F.

    2016-06-01

    In this work a hybrid graphene-based flexible micro-supercapacitor (MSC) exploiting a novel composite material was fabricated and extensively characterized. The MSC electrodes have been obtained from a synthesized composite aerogel of reduced graphene oxide and polycrystalline nanoparticles of molybdenum (IV) oxide (MoO2) and then dispersed in a solution containing poly(3,4-ethylenedioxythiophene) (PEDOT). Usually in MSCs the electrons have to percolate through the nanostructured Three-dimensional (3D) matrix in order to reach the collectors, made by metal thin films that provide electrical contacts only on the surface of active material. In the attempt to enable a more efficient charge transfer and to allow direct electrical contact without metal deposition, in this study a highly doped PEDOT acting both as current collector and as binder for the nanocomposite material has been employed. 3D MSCs were fabricated through a Lithographie, Galvanoformung, Abformung (LIGA)-like process to obtain high aspect ratio microstructures in polydimethylsiloxane replicas. Capacitance values of 94 F g-1 for the nanocomposite and of 14 mF cm-2 for the device were achieved. Moreover, bending test has demonstrated good performance preservation in a U shape conformation of the device.

  3. The scalable design of flapping micro air vehicles inspired by insect flight

    NARCIS (Netherlands)

    Lentink, D.; Jongerius, S.R.; Bradshaw, N.L.

    2009-01-01

    Here we explain how flapping micro air vehicles (MAVs) can be designed at different scales, from bird to insect size. The common believe is that micro fixed wing airplanes and helicopters outperform MAVs at bird scale, but become inferior to flapping MAVs at the scale of insects as small as fruit fl

  4. An experimental study of elastic properties of dragonfly-like flapping wings for use in biomimetic micro air vehicles (BMAVs

    Directory of Open Access Journals (Sweden)

    Praveena Nair Sivasankaran

    2017-04-01

    Full Text Available This article studies the elastic properties of several biomimetic micro air vehicle (BMAV wings that are based on a dragonfly wing. BMAVs are a new class of unmanned micro-sized air vehicles that mimic the flapping wing motion of flying biological organisms (e.g., insects, birds, and bats. Three structurally identical wings were fabricated using different materials: acrylonitrile butadiene styrene (ABS, polylactic acid (PLA, and acrylic. Simplified wing frame structures were fabricated from these materials and then a nanocomposite film was adhered to them which mimics the membrane of an actual dragonfly. These wings were then attached to an electromagnetic actuator and passively flapped at frequencies of 10–250 Hz. A three-dimensional high frame rate imaging system was used to capture the flapping motions of these wings at a resolution of 320 pixels × 240 pixels and 35000 frames per second. The maximum bending angle, maximum wing tip deflection, maximum wing tip twist angle, and wing tip twist speed of each wing were measured and compared to each other and the actual dragonfly wing. The results show that the ABS wing has considerable flexibility in the chordwise direction, whereas the PLA and acrylic wings show better conformity to an actual dragonfly wing in the spanwise direction. Past studies have shown that the aerodynamic performance of a BMAV flapping wing is enhanced if its chordwise flexibility is increased and its spanwise flexibility is reduced. Therefore, the ABS wing (fabricated using a 3D printer shows the most promising results for future applications.

  5. Fixed membrane wings for micro air vehicles: Experimental characterization, numerical modeling, and tailoring

    Science.gov (United States)

    Stanford, Bret; Ifju, Peter; Albertani, Roberto; Shyy, Wei

    2008-05-01

    Fixed wing micro air vehicles (wingspan between 10 and 15 cm) are aerodynamically challenging due to the low Reynolds number regime (10 4-10 5) they operate in. The low aspect ratio wings (typically used to maximize area under a size constraint) promote strong tip vortices, and are susceptible to rolling instabilities. Wind gusts can be of the same order of magnitude as the flight speed (10-15 m/s). Standard control surfaces on an empennage must be eliminated for size considerations and drag reduction, and the range of stable center of gravity locations is only a few millimeters long. Membrane aeroelasticity has been identified as a tenable method to alleviate these issues: flexible wing structures with geometric twist (adaptive washout for gust rejection, delayed stall) and aerodynamic twist (adaptive inflation for high lift, larger stability margins) are both considered here. Recent investigations in static aeroelastic characterization, including flight loads, wing deformation, flow structures, aeroelastic-tailoring studies through laminate orientation, as well as unconventional techniques based on membrane pre-tension, are reviewed. Multi-objective optimization aimed at improving lift, drag, and pitching moment considerations is also discussed.

  6. In vivo micro-CT assessment of airway remodeling in a flexible OVA-sensitized murine model of asthma.

    Directory of Open Access Journals (Sweden)

    Mathieu Lederlin

    Full Text Available Airway remodeling is a major pathological feature of asthma. Up to now, its quantification still requires invasive methods. In this study, we aimed at determining whether in vivo micro-computed tomography (micro-CT is able to demonstrate allergen-induced airway remodeling in a flexible mouse model of asthma. Sixty Balb/c mice were challenged intranasally with ovalbumin or saline at 3 different endpoints (Days 35, 75, and 110. All mice underwent plethysmography at baseline and just prior to respiratory-gated micro-CT. Mice were then sacrificed to assess bronchoalveolar lavage and lung histology. From micro-CT images (voxel size = 46×46×46 µm, the numerical values of total lung attenuation, peribronchial attenuation (PBA, and PBA normalized by total lung attenuation were extracted. Each parameter was compared between OVA and control mice and correlation coefficients were calculated between micro-CT and histological data. As compared to control animals, ovalbumin-sensitized mice exhibited inflammation alone (Day 35, remodeling alone (Day 110 or both inflammation and remodeling (Day 75. Normalized PBA was significantly greater in mice exhibiting bronchial remodeling either alone or in combination with inflammation. Normalized PBA correlated with various remodeling markers such as bronchial smooth muscle size or peribronchial fibrosis. These findings suggest that micro-CT may help monitor remodeling non-invasively in asthmatic mice when testing new drugs targeting airway remodeling in pre-clinical studies.

  7. Microenvironment Tracker (MicroTrac) Model helps track air quality

    Science.gov (United States)

    MicroTrac is a model that uses global positioning system (GPS) data to estimate time of day and duration that people spend in different microenvironments (e.g., indoors and outdoors at home, work, school).

  8. Experimental study of PDMS mechanical properties for the optimization of polymer based flexible pressure micro-sensors

    Science.gov (United States)

    Dinh, T. H. N.; Martincic, E.; Dufour-Gergam, E.; Joubert, P.-Y.

    2016-10-01

    This paper reports on the optimization of flexible PDMS-based normal pressure capacitive micro-sensors dedicated to wearable applications. The deformation under a normal force of PDMS thin films of thicknesses ranging from 40 μm to 10 mm is firstly experimentally studied. This study points out that for capacitive micro-sensors using bulky PDMS thin films as deformable dielectric material, the sensitivity to an applied normal load can be optimized thanks to an adequate choice of the so-called form ratio of the involved PDMS thin film. Indeed, for capacitive micro-sensors exhibiting 9 mm2 electrodes, the capacitance change under a 6 N load can be adjusted from a few percent up to over 35% according to the choice of the load-free thickness of the used PDMS film. These results have been validated thanks to electromechanical characterizations carried out on two flexible PDMS based capacitive normal pressure micro-sensor samples fabricated with two different thicknesses. The obtained results open the way to the enhanced design of PDMS based pressure sensors dedicated to wearable and medical applications. Further works will extend this study to a wider range of sensor dimensions, and using numerical modelling.

  9. Flexible piezoelectric nanogenerators based on a transferred ZnO nanorod/Si micro-pillar array

    Science.gov (United States)

    Baek, Seong-Ho; Park, Il-Kyu

    2017-03-01

    Flexible piezoelectric nanogenerators (PNGs) based on a composite of ZnO nanorods (NRs) and an array of Si micro-pillars (MPs) are demonstrated by a transfer process. The flexible composite structure was fabricated by hydrothermal growth of ZnO NRs on an electrochemically etched Si MP array with various lengths followed by mechanically delaminating the Si MP arrays from the Si substrate after embedding them in a polydimethylsiloxane matrix. Because the Si MP arrays act as a supporter to connect the ZnO NRs electrically and mechanically, verified by capacitance measurement, the output voltage from the flexible PNGs increased systematically with the increased density ZnO NRs depending on the length of the Si MPs. The flexible PNGs showed 3.2 times higher output voltage with a small change in current with increasing Si MP length from 5 to 20 μm. The enhancement of the output voltage is due to the increased number of series-connected ZnO NRs and the beneficial effect of a ZnO NR/Si MP heterojunction on reducing free charge screening effects. The flexible PNGs can be attached on fingers as a wearable electrical power source or motion sensor.

  10. Flexible piezoelectric nanogenerators based on a transferred ZnO nanorod/Si micro-pillar array.

    Science.gov (United States)

    Baek, Seong-Ho; Park, Il-Kyu

    2017-03-03

    Flexible piezoelectric nanogenerators (PNGs) based on a composite of ZnO nanorods (NRs) and an array of Si micro-pillars (MPs) are demonstrated by a transfer process. The flexible composite structure was fabricated by hydrothermal growth of ZnO NRs on an electrochemically etched Si MP array with various lengths followed by mechanically delaminating the Si MP arrays from the Si substrate after embedding them in a polydimethylsiloxane matrix. Because the Si MP arrays act as a supporter to connect the ZnO NRs electrically and mechanically, verified by capacitance measurement, the output voltage from the flexible PNGs increased systematically with the increased density ZnO NRs depending on the length of the Si MPs. The flexible PNGs showed 3.2 times higher output voltage with a small change in current with increasing Si MP length from 5 to 20 μm. The enhancement of the output voltage is due to the increased number of series-connected ZnO NRs and the beneficial effect of a ZnO NR/Si MP heterojunction on reducing free charge screening effects. The flexible PNGs can be attached on fingers as a wearable electrical power source or motion sensor.

  11. Novel adaptive neural control of flexible air-breathing hypersonic vehicles based on sliding mode differentiator

    Directory of Open Access Journals (Sweden)

    Bu Xiangwei

    2015-08-01

    Full Text Available A novel adaptive neural control strategy is exploited for the longitudinal dynamics of a generic flexible air-breathing hypersonic vehicle (FAHV. By utilizing functional decomposition method, the dynamics of FAHV is decomposed into the velocity subsystem and the altitude subsystem. For each subsystem, only one neural network is employed for the unknown function approximation. To further reduce the computational burden, minimal-learning parameter (MLP technology is used to estimate the norm of ideal weight vectors rather than their elements. By introducing sliding mode differentiator (SMD to estimate the newly defined variables, there is no need for the strict-feedback form and virtual controller. Hence the developed control law is considerably simpler than the ones derived from back-stepping scheme. Finally, simulation studies are made to illustrate the effectiveness of the proposed control approach in spite of the flexible effects, system uncertainties and varying disturbances.

  12. Robust tracking control design for a flexible air-breathing hypersonic vehicle

    Institute of Scientific and Technical Information of China (English)

    张垚; 鲜斌; 刁琛; 赵勃; 郭建川

    2014-01-01

    A nonlinear robust controller was presented to improve the tracking control performance of a flexible air-breathing hypersonic vehicle (AHV) which is subjected to system parametric uncertainties and unknown additive time-varying disturbances. The longitudinal dynamic model for the flexible AHV was used for the control development. High-gain observers were designed to compensate for the system uncertainties and additive disturbances. Small gain theorem and Lyapunov based stability analysis were utilized to prove the stability of the closed loop system. Locally uniformly ultimately bounded tracking of the vehicle’s velocity, altitude and attack angle were achieved under aeroelastic effects, system parametric uncertainties and unknown additive disturbances. Matlab/Simulink simulation results were provided to validate the robustness of the proposed control design. The simulation results demonstrate that the tracking errors stay in a small region around zero.

  13. Adaptive Neural Back-Stepping Control with Constrains for a Flexible Air-Breathing Hypersonic Vehicle

    Directory of Open Access Journals (Sweden)

    Pengfei Wang

    2015-01-01

    Full Text Available The design of an adaptive neural back-stepping control for a flexible air-breathing hypersonic vehicle (AHV in the presence of input constraint and aerodynamic uncertainty is discussed. Based on functional decomposition, the dynamics can be decomposed into the velocity subsystem and the altitude subsystem. To guarantee the exploited controller’s robustness with respect to parametric uncertainties, neural network (NN is applied to approximate the lumped uncertainty of each subsystem of AHV model. The exceptional contribution is that novel auxiliary systems are introduced to compensate both the tracking errors and desired control laws, based on which the explored controller can still provide effective tracking of velocity and altitude commands when the actuators are saturated. Finally, simulation studies are made to illustrate the effectiveness of the proposed control approach in spite of the flexible effects, system uncertainties, and varying disturbances.

  14. Evaluation of the effects of enameloplasty and air abrasion on sealant micro-leakage.

    Directory of Open Access Journals (Sweden)

    Aliasghar Soleymani

    2014-12-01

    Full Text Available Micro-leakage, one of the major reasons for recurrent decays, may lead to uncontrollable flow of liquids, pulp inflammation and peri-apical pathology. The purpose of this in vitro study was to evaluate micro-leakage of pit and fissure sealants after using three different pit and fissure preparation techniques: 1 acid etching, 2 fissure enameloplasty and acid etching, and 3 air abrasion and acid etching.Sixty-nine extracted sound molars and premolars were randomly divided into three groups (23 samples in each group. Teeth were prepared using one of three occlusal surface treatments. Then the sealant was applied on the occlusal fissures of all teeth. The teeth were thermocycled and stored in normal saline. All teeth were sealed apically and coated with nail varnish and then were immersed in a 2% solution of methylen blue. Two buccolingual sections were made. The surfaces were scored 0 to 3 for the extent of micro-leakage using a stereomicroscope. Data were analyzed by Kruskal- wallis and Dunn procedure.Enameloplasty and acid etching were significantly different regarding micro-leakage (P= 0.016, but no significant difference in micro-leakage was observed between air abrasion and the other methods.Enameloplasty followed by acid etching produced significantly less micro-leakage than the acid etching technique. Air abrasion acid etching was better than the acid etching technique in reducing micro-leakage too.

  15. Air-side performance of a micro-channel heat exchanger in wet surface conditions

    Directory of Open Access Journals (Sweden)

    Srisomba Raviwat

    2017-01-01

    Full Text Available The effects of operating conditions on the air-side heat transfer, and pressure drop of a micro-channel heat exchanger under wet surface conditions were studied experimentally. The test section was an aluminum micro-channel heat exchanger, consisting of a multi-louvered fin and multi-port mini-channels. Experiments were conducted to study the effects of inlet relative humidity, air frontal velocity, air inlet temperature, and refrigerant temperature on air-side performance. The experimental data were analyzed using the mean enthalpy difference method. The test run was performed at relative air humidities ranging between 45% and 80%; air inlet temperature ranges of 27, 30, and 33°C; refrigerant-saturated temperatures ranging from 18 to 22°C; and Reynolds numbers between 128 and 166. The results show that the inlet relative humidity, air inlet temperature, and the refrigerant temperature had significant effects on heat transfer performance and air-side pressure drop. The heat transfer coefficient and pressure drop for the micro-channel heat exchanger under wet surface conditions are proposed in terms of the Colburn j factor and Fanning f factor.

  16. Piezoelectric energy harvesting from morphing wing motions for micro air vehicles

    KAUST Repository

    Abdelkefi, Abdessattar

    2013-09-10

    Wing flapping and morphing can be very beneficial to managing the weight of micro air vehicles through coupling the aerodynamic forces with stability and control. In this letter, harvesting energy from the wing morphing is studied to power cameras, sensors, or communication devices of micro air vehicles and to aid in the management of their power. The aerodynamic loads on flapping wings are simulated using a three-dimensional unsteady vortex lattice method. Active wing shape morphing is considered to enhance the performance of the flapping motion. A gradient-based optimization algorithm is used to pinpoint the optimal kinematics maximizing the propellent efficiency. To benefit from the wing deformation, we place piezoelectric layers near the wing roots. Gauss law is used to estimate the electrical harvested power. We demonstrate that enough power can be generated to operate a camera. Numerical analysis shows the feasibility of exploiting wing morphing to harvest energy and improving the design and performance of micro air vehicles.

  17. Micro GC's for Contaminant Monitoring in Spacecraft Air Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this proposal is to create new gas chromatographs (GCs) for contaminant monitoring in spacecraft air that do not require any reagents or special...

  18. A normally-closed piezoelectric micro-valve with flexible stopper

    Science.gov (United States)

    Chen, Song; Lu, Song; Liu, Yong; Wang, Jiantao; Tian, Xiaochao; Liu, Guojun; Yang, Zhigang

    2016-04-01

    In the field of controlled drug delivery system, there are still many problems on those reported micro-valves, such as the small opening height, unsatisfactory particle tolerance and high cost. To solve the above problems, a novel normally-closed piezoelectric micro-valve is presented in this paper. The micro-valve was driven by circular unimorph piezoelectric vibrator and natural rubber membrane with high elasticity was used as the valve stopper. The small axial displacement of piezoelectric vibrator can be converted into a large stroke of valve stopper based on hydraulic amplification mechanism. The experiment indicates that maximum hydraulic amplification ratio is up to 14, and the cut-off pressure of the micro-valve is 39kPa in the case of no working voltage. The presented micro valve has a large flow control range (ranging from 0 to 8.75mL/min).

  19. Research on film thickness of conductive line formed by laser micro-fine cladding and flexibly direct writing technique

    Institute of Scientific and Technical Information of China (English)

    Huiling Li(李慧玲); Xiaoyan Zeng(曾晓雁); Huifen Li(李惠芬); Xiangyou Li(李祥友); Yiqun Chen(陈佚群)

    2004-01-01

    The conventional technology could not fulfill the rapidly growing need for fine conductive lines for its inherent limits. Therefore, in this study laser micro-fine cladding and flexibly direct writing technique is used to obtain conductive lines with high precision and reliability. In the case of different substrates and parameters, film thickness will be different. Film thickness directly influences the reliability and stability of conductive lines with exception of quality and running speed. Therefore, we focus on developing the optimal parameters for the different substrates to achieve expected film thickness and make conductive lines have good performance and quality.

  20. NONLINEAR DYNAMICS OF LATERAL MICRO-RESONATOR INCLUDING VISCOUS AIR DAMPING

    Institute of Scientific and Technical Information of China (English)

    GAO Rong; WANG Xiaojing; WANG Min; YU Maohua; XIE Mingchun

    2007-01-01

    The nonlinear dynamics of the lateral micro-resonator including the air damping effect is researched. The air damping force is varied periodically during the resonator oscillating, and the air damp coefficient can not be fixed as a constant. Therefore the linear dynamic analysis which used the constant air damping coefficient can not describe the actual dynamic characteristics of the micro-resonator. The nonlinear dynamic model including the air damping force is established. On the base of Navier-Stokes equation and nonlinear dynamical equation, a coupled fluid-solid numerical simulation method is developed and demonstrates that damping force is a vital factor in micro-comb structures. Compared with existing experimental result, the nonlinear numerical value has quite good agreement with it. The differences of the amplitudes (peak) between the experimental data and the results by the linear model and the nonlinear model are 74.5% and 6% respectively. Nonlinear numerical value is more exact than linear value and the method can be applied in other micro-electro-mechanical systeme (MEMS) structures to simulate the dynamic performance.

  1. The flow feature of transverse hydrogen jet in presence of micro air jets in supersonic flow

    Science.gov (United States)

    Barzegar Gerdroodbary, M.; Amini, Younes; Ganji, D. D.; Takam, ​M. Rahimi

    2017-03-01

    Scramjet is found to be the efficient method for the space shuttle. In this paper, numerical simulation is performed to investigate the fundamental flow physics of the interaction between an array of fuel jets and multi air jets in a supersonic transverse flow. Hydrogen as a fuel is released with a global equivalence ratio of 0.5 in presence of micro air jets on a flat plate into a Mach 4 crossflow. The fuel and air are injected through streamwise-aligned flush circular portholes. The hydrogen is injected through 4 holes with 7dj space when the air is injected in the interval of the hydrogen jets. The numerical simulation is performed by using the Reynolds-averaged Navier-Stokes equations with Menter's Shear Stress Transport (SST) turbulence model. Both the number of air jets and jet-to-freestream total pressure ratio are varied in a parametric study. The interaction of the fuel and air jet in the supersonic flow present extremely complex feature of fuel and air jet. The results present various flow features depending upon the number and mass flow rate of micro air jets. These flow features were found to have significant effects on the penetration of hydrogen jets. A variation of the number of air jets, along with the jet-to-freestream total pressure ratio, induced a variety of flow structure in the downstream of the fuel jets.

  2. Flexible Transfer of Regolith in Micro-Gravity and Vacuum Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A novel, robust method of collection and transfer of NEO/Phobos material under micro-gravity conditions under vacuum/space environment with minimal loss of volatiles...

  3. Copper Micro-Labyrinth with Graphene Skin: New Transparent Flexible Electrodes with Ultimate Low Sheet Resistivity and Superior Stability

    Directory of Open Access Journals (Sweden)

    Hak Ki Yu

    2016-09-01

    Full Text Available We have developed self-assembled copper (Cu micro-labyrinth (ML with graphene skin for transparent flexible electrodes of optoelectronic devices. The Cu ML is simply formed by heating a thin Cu film with a 100-nm thickness on a SiO2/Si substrate at 950 °C under hydrogen ambient to block the oxidation. Moreover, the Cu ML can have graphene skin at the surface by inserting carbo-hydroxyl molecules (CxHy during heating due to the catalytic decomposition of C–H bonds on the Cu surface. The Cu ML with graphene skin (Cu ML-G has superior sheet resistivity below 5 Ω/sq and mechanical flexibility without cracks at the bending radius of 0.1 cm. Although the transmittance of Cu ML-G is a little lower (70%~80% than that of conventional metallic nanowires electrodes (such as Ag, ~90% at the visible wavelength, it has good thermal stability in conductivity without any damage at 200 °C due to a micro-sized pattern and graphene skin which prohibits the surface migration of Cu atoms.

  4. Reliable Force Predictions for a Flapping-wing Micro Air Vehicle : A "Vortex-lift" Approach

    NARCIS (Netherlands)

    Thielicke, W.; Kesel, A. B.; Stamhuis, Eize

    2011-01-01

    Vertical and horizontal force of a flapping-wing micro air vehicle (MAV) has been measured in slow-speed forward flight using a force balance. Detailed information on kinematics was used to estimate forces using a blade-element analysis. Input variables for this analysis are lift and drag coefficien

  5. Aerodynamics of flapping-wing Micro-Air-Vehicle: An integrated experimental and numerical study

    NARCIS (Netherlands)

    Deng, S.

    2016-01-01

    The interest in Micro Air Vehicles (MAVs) has stimulated continuous research activities, in view of their potential in civilian and military applications. An autonomous MAV with dedicated onboard sensors would be capable of executing mission in closed environments, such as surveillance, in door insp

  6. Experimental Methods to Characterize Nonlinear Vibration of Flapping Wing Micro Air Vehicles

    Science.gov (United States)

    2007-03-01

    the following terminology when referring to flapping wing MAVs; bird flight machines are also known as ornithopters and robotic insects are also...15. SUBJECT TERMS Flapping Wing Micro Air Vehicle, flapping-wing MAV, MAV, ornithopter , entomopter, nonlinear vibration, beam resonance

  7. Laser Dot Projection Photogrammetry and Force Balance Measurement Techniques for Flapping Wing Micro Air Vehicles

    Science.gov (United States)

    2008-03-01

    Parameters of Force Balance Channels ............................................................. 39  1 BIOMIMETIC MICRO AIR VEHICLE...used two high speed cameras to research the flight of butterflies in their natural habitat. They set-up the cameras in a butterfly vivarium and...captured images of multiple butterflies performing multiple flight maneuvers. Images were captured at 100-200 Hz. Using software, certain body parts

  8. Easy 3D mapping for indoor navigation of unmanned micro air vehicles

    DEFF Research Database (Denmark)

    Schiøler, Henrik; Totu, Luminita Cristiana; La Cour-Harbo, Anders

    2017-01-01

    Indoor operation of micro air vehicles (UAS or UAV) is significantly simplified with the availability of some means for indoor localization as well as a sufficiently precise 3D map of the facility. Creation of 3D maps based on the available architectural information should on the one hand provide...

  9. Ornithopter Type Flapping Wings for Autonomous Micro Air Vehicles

    Directory of Open Access Journals (Sweden)

    Sutthiphong Srigrarom

    2015-05-01

    Full Text Available In this paper, an ornithopter prototype that mimics the flapping motion of bird flight is developed, and the lift and thrust generation characteristics of different wing designs are evaluated. This project focused on the spar arrangement and material used for the wings that could achieves improved performance. Various lift and thrust measurement techniques are explored and evaluated. Various wings of insects and birds were evaluated to understand how these natural flyers with flapping wings are able to produce sufficient lift to fly. The differences in the flapping aerodynamics were also detailed. Experiments on different wing designs and materials were conducted and a paramount wing was built for a test flight. The first prototype has a length of 46.5 cm, wing span of 88 cm, and weighs 161 g. A mechanism which produced a flapping motion was fabricated and designed to create flapping flight. The flapping flight was produced by using a single motor and a flexible and light wing structure. A force balance made of load cell was then designed to measure the thrust and lift force of the ornithopter. Three sets of wings varying flexibility were fabricated, therefore lift and thrust measurements were acquired from each different set of wings. The lift will be measured in ten cycles computing the average lift and frequency in three different speeds or frequencies (slow, medium and fast. The thrust measurement was measure likewise but in two cycles only. Several observations were made regarding the behavior of flexible flapping wings that should aid in the design of future flexible flapping wing vehicles. The wings angle or phase characteristic were analyze too and studied. The final ornithopter prototype weighs only 160 g, has a wing span of 88.5 cm, that could flap at a maximum flapping frequency of 3.869 Hz, and produce a maximum thrust and lift of about 0.719 and 0.264 N respectively. Next, we proposed resonance type flapping wing utilizes the near

  10. The Use of Compressed Air for Micro-Jet Cooling After MIG Welding

    Directory of Open Access Journals (Sweden)

    Hadryś D.

    2016-09-01

    Full Text Available The material selected for this investigation was low alloy steel weld metal deposit (WMD after MIG welding with micro-jet cooling. The present investigation was aimed as the following tasks: obtained WMD with various amount of acicular ferrite and further analyze impact toughness of WMD in terms of acicular ferrite amount in it. Weld metal deposit (WMD was first time carried out for MIG welding with micro-jet cooling of compressed air and gas mixture of argon and air. Until that moment only argon, helium and nitrogen were tested as micro-jet gases for MIG/MAG processes. An important role in the interpretation of the results can give methods of artificial intelligence.

  11. Rigid-flexible outer sheath model using slider linkage locking mechanism and air pressure for endoscopic surgery.

    Science.gov (United States)

    Yagi, Akihiko; Matsumiya, Kiyoshi; Masamune, Ken; Liao, Hongen; Dohi, Takeyoshi

    2006-01-01

    The objective of this paper is to develop an outer sheath for flexible endoscopic manipulators. This sheath can switch two states including flexible and rigid, and make a rigid curved path for inserting manipulators. The flexible mode can be curved into a required shape. The rigid mode can hold the shape of the sheath, and then keep the path for instruments. Through the managed path, the flexible manipulators become easy to reach the target. We proposed a serial multi joint model to realize the flexible mechanism. This model is composed of a set of frame units which are connected serially. Each unit can be rotated to a given angle around the center of the joint. We developed a slider-link mechanism and a gear stopper controlled by air pressure for rigid mode. We designed and fabricated the prototype with a diameter of 16 mm and length of 290 mm. The experiment showed that the device could be switched from the flexible mode to the rigid mode when the air pressure was over 150 kPa, and each joint could hold its angle against the maximum 400 mNm. The phantom experiment showed that the flexible devices are possible to transmit the wire tension to the endpoint of the manipulator without changing the curving shape with by the developed outer sheath device.

  12. Continuous high order sliding mode controller design for a flexible air-breathing hypersonic vehicle.

    Science.gov (United States)

    Wang, Jie; Zong, Qun; Su, Rui; Tian, Bailing

    2014-05-01

    This paper investigates the problem of tracking control with uncertainties for a flexible air-breathing hypersonic vehicle (FAHV). In order to overcome the analytical intractability of this model, an Input-Output linearization model is constructed for the purpose of feedback control design. Then, the continuous finite time convergence high order sliding mode controller is designed for the Input-Output linearization model without uncertainties. In addition, a nonlinear disturbance observer is applied to estimate the uncertainties in order to compensate the controller and disturbance suppression, where disturbance observer and controller synthesis design is obtained. Finally, the synthesis of controller and disturbance observer is used to achieve the tracking for the velocity and altitude of the FAHV and simulations are presented to illustrate the effectiveness of the control strategies.

  13. A MEMS-based Air Flow Sensor with a Free-standing Micro-cantilever Structure

    Directory of Open Access Journals (Sweden)

    Che-Ming Chiang

    2007-10-01

    Full Text Available This paper presents a micro-scale air flow sensor based on a free-standingcantilever structure. In the fabrication process, MEMS techniques are used to deposit asilicon nitride layer on a silicon wafer. A platinum layer is deposited on the silicon nitridelayer to form a piezoresistor, and the resulting structure is then etched to create afreestanding micro-cantilever. When an air flow passes over the surface of the cantileverbeam, the beam deflects in the downward direction, resulting in a small variation in theresistance of the piezoelectric layer. The air flow velocity is determined by measuring thechange in resistance using an external LCR meter. The experimental results indicate that theflow sensor has a high sensitivity (0.0284 ω/ms-1, a high velocity measurement limit (45ms-1 and a rapid response time (0.53 s.

  14. Flexible inverted polymer solar cells fabricated in air at low temperatures

    Science.gov (United States)

    Kuwabara, Takayuki; Wang, Xiaofan; Kusumi, Takuji; Yamaguchi, Takahiro; Taima, Tetsuya; Takahashi, Kohshin

    2016-08-01

    A series of modified indium tin oxide (ITO) materials, including sol-gel zinc-oxide-coated ITO (ITO/ZnO), ZnO nanoparticle-coated ITO (ITO/ZnO-NP), 1,4-bis(3-aminopropyl)piperazine (BAP)-modified ITO, and polyethylenimine ethoxylated (PEIE)-modified ITO, were used for electron-collection electrodes in inverted polymer solar cells (PSCs). The modified ITO electrodes were prepared in air at temperatures below 100 °C, using various ITO films on flexible poly(ethylene terephthalate) substrates (PET-ITO) with sheet resistances ranging from 12 to 60 Ω sq-1. The PET-ITO (12 Ω sq-1)/ZnO-NP PSC exhibited an improved power conversion efficiency (PCE) (2.93%), and this PCE was ˜90% of that observed for a cell using glass-ITO/ZnO-NP (sheet resistance = 10 Ω sq-1 PCE = 3.28%). Additionally, we fabricated a flexible inverted ZnO-NP PSC using an indene-C60 bisadduct (ICBA) as the acceptor material in place of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and obtained a PCE of 4.18%.

  15. Pneumatic-aided micro-molding for flexible fabrication of homogeneous and heterogeneous cell-laden microgels.

    Science.gov (United States)

    Ma, Chao; Tian, Chang; Zhao, Lei; Wang, Jinyi

    2016-07-01

    Microgels are favorable for numerous applications such as drug delivery, biomaterials science and tissue engineering. Conventionally, photolithographic methods and micro-molding techniques are extensively exploited to prepare microgels; however, they are, respectively, limited to photocrosslinkable polymers and inadequate to generate serially patterned hydrogels due to the static nature of utilized molds. Herein, we proposed a simple and versatile approach, termed pneumatic-aided micro-molding (PAM), to flexibly fabricate microgels with precise control over multiple cell types and microarchitectures of hydrogels through strategically designed pneumatic microvalves. Using the PAM approach, different cells were encapsulated in various hydrogels that had well-defined geometries. Additionally, single/multiple micro-channeled cell-laden microgels were fabricated, of which the shape, number and arrangement could be finely tuned by varying microvalve configurations. Moreover, multi-compartmental microgels comprising composite hydrogel structures were engineered following a two-step PAM, which demonstrated the utility for biomimetically constructing a three-dimensional (3D) liver microtissue composed of a radially orchestrated network of hepatic cords and sinusoids. The resulting microtissue resembled the organizational complexity of the liver lobule and was applied for the evaluation of acetaminophen-induced hepatotoxicity. Collectively, the PAM strategy could be a useful and powerful tool in biomedical engineering, in vitro 3D cell culture, and fundamental biological studies.

  16. Hygroscopic and thermal micro deformations of plastic substrates for flexible electronics using digital image correlation

    NARCIS (Netherlands)

    Berg, D. van den; Barink, M.; Giesen, P.; Meinders, E.R.; Yakimets, I.

    2010-01-01

    Thin polymer substrates are promising materials for flexible electronics with many advantages. However, the dimensional stability of polymer substrates is low. Nowadays, this is overcome by laminating polymer substrates onto a rigid carrier. Nevertheless, carrier-less processing will be a foreseen n

  17. Hygroscopic and thermal micro deformations of plastic substrates for flexible electronics using digital image correlation

    NARCIS (Netherlands)

    Berg, D. van den; Barink, M.; Giesen, P.; Meinders, E.R.; Yakimets, I.

    2011-01-01

    Thin polymer substrates are promising materials for flexible electronics with many advantages. However, the dimensional stability of polymer substrates is low. Nowadays, this is overcome by laminating polymer substrates onto a rigid carrier. Nevertheless, carrier-less processing will be a foreseen n

  18. Aerodynamics and flight performance of flapping wing micro air vehicles

    Science.gov (United States)

    Silin, Dmytro

    Research efforts in this dissertation address aerodynamics and flight performance of flapping wing aircraft (ornithopters). Flapping wing aerodynamics was studied for various wing sizes, flapping frequencies, airspeeds, and angles of attack. Tested wings possessed both camber and dihedral. Experimental results were analyzed in the framework of momentum theory. Aerodynamic coefficients and Reynolds number are defined using a reference velocity as a vector sum of a freestream velocity and a strokeaveraged wingtip velocity. No abrupt stall was observed in flapping wings for the angle of attack up to vertical. If was found that in the presence of a freestream lift of a flapping wing in vertical position is higher than the propulsive thrust. Camber and dihedral increased both lift and thrust. Lift-curve slope, and maximum lift coefficient increased with Reynolds number. Performance model of an ornithopter was developed. Parametric studies of steady level flight of ornithopters with, and without a tail were performed. A model was proposed to account for wing-sizing effects during hover. Three micro ornithopter designs were presented. Ornithopter flight testing and data-logging was performed using a telemetry acquisition system, as well as motion capture technology. The ability of ornithopter for a sustained flight and a presence of passive aerodynamic stability were shown. Flight data were compared with performance simulations. Close agreement in terms of airspeed and flapping frequency was observed.

  19. Simulation Studies Of Premixed N-Pentane/Air Liquid Micro Combustion

    Directory of Open Access Journals (Sweden)

    G.B. Arivazhagan

    2015-03-01

    Full Text Available With latest improvements in MEMS, combustion based Micro-Power generation devices are seen as alternatives for conventional batteries because of the high energy densities of Hydrogen and other hydrocarbon fuels. An important feature of micro-power system is to utilize the combustion of fuel or propellant in the micro-burner to produce the gas with high temperature and high pressure to drive turbines or other power units, which convert chemical into energy directly or indirectly other forms of energy, for example heat or power. We have concentrated on the usage of Micro combustion as a substitute for conventional batteries .In our study, a Micro Combustor of 1mm x 10mm is taken for Numerical Study. Combustion characteristics of N Pentane-Air mixture in a planar micro-channel is studied numerically. We have performed the liquid fuel combustion of n-Pentane and air to study the effects of liquid fuel combustion in a micro channel. The effect of axial velocity inlet, on exhaust gas temperature and Hydrogen Peroxide addition on exhaust gas concentration was analyzed respectively. We also investigated numerically the combustion characteristics under different conditions such as by varying the DPM, Number of Fuel Streams, and Spray Angle and so on. For this numerical analysis, an experimental model is considered as reference, and the geometry and the boundary conditions are taken from it for the purpose of simulation. In this study, n-Pentane is introduced as liquid droplets at the centerline and the liquid combustion is simulated numerically.

  20. Micro/Nano-Structured Flexible Foils for Anti-Counterfeiting Purposes

    DEFF Research Database (Denmark)

    Okulova, Nastasia

    2016-01-01

    Up to date there have been found many ways of producing samples with functional nano-pattering, however for mass production of such samples the method of fabrication of the surface structure must be fast and cheap. A recently developed method suggests using extrusion coating of polymer materials...... in a roll-to roll process, where the functional micro-/nano- surface structures are imprinted directly onto the surface of a polymer foil. This new technology can both answer the requirement for being fast and cheap. The aim of this project is implementation of the technology for mass production...... has been demonstrated. The focus of this study lies on the reproduction of the previous results for nano- or micro-structures and implementation of this technology for mass production of such patterned foils for the use in packaging. An interesting application is production of holograms with build...

  1. Robotic hummingbird: Design of a control mechanism for a hovering flapping wing micro air vehicle

    OpenAIRE

    Karasek, Matej

    2014-01-01

    The use of drones, also called unmanned aerial vehicles (UAVs), is increasing every day. These aircraft are piloted either remotely by a human pilot or completely autonomously by an on-board computer. UAVs are typically equipped with a video camera providing a live video feed to the operator. While they were originally developed mainly for military purposes, many civil applications start to emerge as they become more affordable.Micro air vehicles are a subgroup of UAVs with a size and weight ...

  2. Inertial attitude control of a bat-like morphing-wing micro air vehicle

    OpenAIRE

    2013-01-01

    This article presents a novel bat-like micro air vehicle inspired by the morphing-wing mechanism of bats. The goal of this paper is twofold. Firstly, a modelling framework is introduced for analysing how the robot should maneuver by means of changing wing morphology. This allows the definition of requirements for achieving forward and turning flight according to the kinematics of the wing modulation. Secondly, an attitude controller named backstepping+DAF is proposed. Motivated by the biologi...

  3. Flexible, Stretchable, and Rechargeable Fiber-Shaped Zinc-Air Battery Based on Cross-Stacked Carbon Nanotube Sheets.

    Science.gov (United States)

    Xu, Yifan; Zhang, Ye; Guo, Ziyang; Ren, Jing; Wang, Yonggang; Peng, Huisheng

    2015-12-14

    The fabrication of flexible, stretchable and rechargeable devices with a high energy density is critical for next-generation electronics. Herein, fiber-shaped Zn-air batteries, are realized for the first time by designing aligned, cross-stacked and porous carbon nanotube sheets simultaneously that behave as a gas diffusion layer, a catalyst layer, and a current collector. The combined remarkable electronic and mechanical properties of the aligned carbon nanotube sheets endow good electrochemical properties. They display excellent discharge and charge performances at a high current density of 2 A g(-1) . They are also flexible and stretchable, which is particularly promising to power portable and wearable electronic devices.

  4. Injection molding micro patterns with high aspect ratio using a polymeric flexible stamper

    Directory of Open Access Journals (Sweden)

    2011-11-01

    Full Text Available Poor filling occurs during the injection molding process of micro- or nano- scale patterns mainly because the hot polymer melt rapidly cools and its skin quickly solidifies upon contact with the mold surface. In this study, it is proposed to use Polyethylene terephthalate (PET film coated with patterned polyurethane acrylate (PUA as an effective thermal barrier. It can significantly hinder heat transfer into the mold during the molding process and thus may keep the melt viscosity low for longer duration. As a result, the replication would be improved not only during the filling phase but also during the packing phase. In order to verify the validity of the use of polymeric stamper, the melt-film interface temperature was evaluated by numerical simulation. Experimental results indicated that patterns possessing widths within the range of one to tens of micrometers and a height of approximately 10 µm were successfully filled and demolded.

  5. Fabrication of a micro through-hole array by gas-blowing a PDMS-treated polyamide screen for a flexible drag-reducing skin-like device

    Science.gov (United States)

    Li, Yong; Zhou, Kai; Zhao, Xiang; Kong, Quancun

    2017-01-01

    We propose a method for fabricating a flexible skin-like device for generating and trapping micro bubbles with the aim of reducing underwater drag. This low-cost, efficient, high-pressure gas-blow method is used to fabricate a micro through-hole array in a flexible polydimethylsiloxane (PDMS) gel-based skin. The key parameters in the gas-blowing method are investigated, such as the viscosity of PDMS and the blowing pressure in order to optimize the quality of through-hole layer. Deviation of the linear dimensions of the obtained micro holes was less than 4.5%. In addition, multiphase computational fluid dynamics models were built to analyze the drag-reduction performance of bell-shaped holes made by this method. Compared with cylindrical through holes produced by molding, the drag-reduction effect of bell-shaped holes increased as much as 34%.

  6. In-air micro-PIGE measurement system for fluorine analysis of the tooth

    Science.gov (United States)

    Yasuda, K.; Hai, V. H.; Nomachi, M.; Sugaya, Y.; Yamamoto, H.

    2007-07-01

    An in-air micro-PIGE and micro-PIXE measurement system for fluorine analysis of tooth have been developed at the Wakasa Wan Energy Research Center. A proton microbeam is extracted through a thin silicon nitride window into the air and used to irradiate a tooth sample mounted on a sample stage set in air. Gamma-rays from a 19F(p, αγ) 16O reaction and characteristic X-rays are detected with a BGO detector and a Ge X-ray detector, simultaneously. The sample stage and beam scanner allow us to analyze the tooth sample over a range of 20 mm at maximum. Spot sizes of a proton beams in air at an energy of 2.5 MeV was 4 μm, in the case of a distance between the silicon nitride window and the sample of 0.2 mm and 13 μm in the case of 1.7 mm. Fluorine analysis was performed over an area of about 3 mm × 3 mm of the tooth sample. One- and two-dimensional distributions of fluorine and calcium were obtained successfully. Quantitative analysis was also performed using data for measurements of reference materials Ca 10(PO 4) 6(OH) 2-2 xF 2 x.

  7. Defect Engineering toward Atomic Co-Nx -C in Hierarchical Graphene for Rechargeable Flexible Solid Zn-Air Batteries.

    Science.gov (United States)

    Tang, Cheng; Wang, Bin; Wang, Hao-Fan; Zhang, Qiang

    2017-08-07

    Rechargeable flexible solid Zn-air battery, with a high theoretical energy density of 1086 Wh kg(-1) , is among the most attractive energy technologies for future flexible and wearable electronics; nevertheless, the practical application is greatly hindered by the sluggish oxygen reduction reaction/oxygen evolution reaction (ORR/OER) kinetics on the air electrode. Precious metal-free functionalized carbon materials are widely demonstrated as the most promising candidates, while it still lacks effective synthetic methodology to controllably synthesize carbocatalysts with targeted active sites. This work demonstrates the direct utilization of the intrinsic structural defects in nanocarbon to generate atomically dispersed Co-Nx -C active sites via defect engineering. As-fabricated Co/N/O tri-doped graphene catalysts with highly active sites and hierarchical porous scaffolds exhibit superior ORR/OER bifunctional activities and impressive applications in rechargeable Zn-air batteries. Specifically, when integrated into a rechargeable and flexible solid Zn-air battery, a high open-circuit voltage of 1.44 V, a stable discharge voltage of 1.19 V, and a high energy efficiency of 63% at 1.0 mA cm(-2) are achieved even under bending. The defect engineering strategy provides a new concept and effective methodology for the full utilization of nanocarbon materials with various structural features and further development of advanced energy materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Micro-properties of a Type Steel Annealed in Air and Vacuum

    Institute of Scientific and Technical Information of China (English)

    LIU Gui-min; MA Li-li; KURZYDLOWSKI Krzysztof Jan

    2004-01-01

    Micro-properties of the oxide scale and near-surface zone of a type 316 steel annealed in air and vacuum have been systematically investigated. Microstmctures of the specimens have been examined using optical microscopy and scanning and transmission electron microscopy (TEM). Chemical compositions for the oxide scale and near surface zone were also analysed. The results obtained show that the oxide scale developed in vacuum exhibits a distinct structure from that developed in air. Comparing to the vacuum-developed scale, the air-developed scale possesses a more complicated structure and relatively poor adhesion to the matrix. TEM observations reveal a difference in the dislocation density in the vicinity of the free surface, near-surface zone and the core of the specimens examined.

  9. Flexible micro supercapacitors based on laser-scribed graphene/ZnO nanocomposite

    Science.gov (United States)

    Amiri, Morteza Hassanpour; Namdar, Naser; Mashayekhi, Alireza; Ghasemi, Foad; Sanaee, Zeinab; Mohajerzadeh, Shams

    2016-08-01

    We report on the fabrication of graphene/Zno nanocomposite supercapacitor electrodes. Laser-scribing process was implemented in order to reduce the graphene oxide (GO)/ZnO mixture on a DVD disk. With reduced graphene oxide (rGO)/ZnO composite prepared by a mass ratio of 1:25 of Zn(NO3)2·6H2O to GO constituents, nanoparticles of ZnO with sizes ranging from 20 to 50 nm are obtained. Consequently, 12 times improvement in the specific capacitance was achieved at a current density of 0.1 mA/cm2 compared with pristine rGO electrodes. In addition, flexible microsupercapacitor was fabricated by spin coating of the gel electrolyte, showing high stack capacitance of 9 F/cm3 at a current density of 150 mA/cm2. This microsupercapacitor delivers power density of 70 mW/cm3 and energy density of 1.2 mWh/cm3. Furthermore, the performance of device was investigated at different bending angles. The resulted characteristics demonstrate that LSG/ZnO nanocomposite is a promising electrode material for high-performance supercapacitors.

  10. Innovative micro-textured hydroxyapatite and poly(l-lactic)-acid polymer composite film as a flexible, corrosion resistant, biocompatible, and bioactive coating for Mg implants.

    Science.gov (United States)

    Kim, Sae-Mi; Kang, Min-Ho; Kim, Hyoun-Ee; Lim, Ho-Kyung; Byun, Soo-Hwan; Lee, Jong-Ho; Lee, Sung-Mi

    2017-12-01

    The utility of a novel ceramic/polymer-composite coating with a micro-textured microstructure that would significantly enhance the functions of biodegradable Mg implants is demonstrated here. To accomplish this, bioactive hydroxyapatite (HA) micro-dots can be created by immersing a Mg implant with a micro-patterned photoresist surface in an aqueous solution containing calcium and phosphate ions. The HA micro-dots can then be surrounded by a flexible poly(l-lactic)-acid (PLLA) polymer using spin coating to form a HA/PLLA micro-textured coating layer. The HA/PLLA micro-textured coating layer showed an excellent corrosion resistance when it was immersed in a simulated body fluid (SBF) solution and good biocompatibility, which was assessed by in vitro cell tests. In addition, the HA/PLLA micro-textured coating layer had high deformation ability, where no apparent changes in the coating layer were observed even after a 5% elongation, which would be unobtainable using HA and PLLA coating layers; furthermore, this allowed the mechanically-strained Mg implant with the HA/PLLA micro-textured coating layer to preserve its excellent corrosion resistance and biocompatibility in vitro. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Nitrogen-Doped Co3 O4 Mesoporous Nanowire Arrays as an Additive-Free Air-Cathode for Flexible Solid-State Zinc-Air Batteries.

    Science.gov (United States)

    Yu, Minghao; Wang, Zhengke; Hou, Cheng; Wang, Zilong; Liang, Chaolun; Zhao, Cunyuan; Tong, Yexiang; Lu, Xihong; Yang, Shihe

    2017-02-10

    The kinetically sluggish rate of oxygen reduction reaction (ORR) on the cathode side is one of the main bottlenecks of zinc-air batteries (ZABs), and thus the search for an efficient and cost-effective catalyst for ORR is highly pursued. Co3 O4 has received ever-growing interest as a promising ORR catalyst due to the unique advantages of low-cost, earth abundance and decent catalytic activity. However, owing to the poor conductivity as a result of its semiconducting nature, the ORR activity of the Co3 O4 catalyst is still far below the expectation. Herein, we report a controllable N-doping strategy to significantly improve the catalytic activity of Co3 O4 for ORR and demonstrate these N doped Co3 O4 nanowires as an additive-free air-cathode for flexible solid-state zinc-air batteries. The results of experiments and DFT calculations reveal that the catalytic activity is promoted by the N dopant through a combined set of factors, including enhanced electronic conductivity, increased O2 adsorption strength and improved reaction kinetics. Finally, the assembly of all-solid-state ZABs based on the optimized cathode exhibit a high volumetric capacity of 98.1 mAh cm(-3) and outstanding flexibility. The demonstration of such flexible ZABs provides valuable insights that point the way to the redesign of emerging portable electronics.

  12. An evolutionarily conserved mutual interdependence between Aire and microRNAs in promiscuous gene expression.

    Science.gov (United States)

    Ucar, Olga; Tykocinski, Lars-Oliver; Dooley, James; Liston, Adrian; Kyewski, Bruno

    2013-07-01

    The establishment and maintenance of central tolerance depends to a large extent on the ability of medullary thymic epithelial cells to express a variety of tissue-restricted antigens, the so-called promiscuous gene expression (pGE). Autoimmune regulator (Aire) is to date the best characterised transcriptional regulator known to at least partially coordinate pGE. There is accruing evidence that the expression of Aire-dependent and -independent genes is modulated by higher order chromatin configuration, epigenetic modifications and post-transcriptional control. Given the involvement of microRNAs (miRNAs) as potent post-transcriptional modulators of gene expression, we investigated their role in the regulation of pGE in purified mouse and human thymic epithelial cells (TECs). Microarray profiling of TEC subpopulations revealed evolutionarily conserved cell type and differentiation-specific miRNA signatures with a subset of miRNAs being significantly upregulated during terminal medullary thymic epithelial cell differentiation. The differential regulation of this subset of miRNAs was correlated with Aire expression and some of these miRNAs were misexpressed in the Aire knockout thymus. In turn, the specific absence of miRNAs in TECs resulted in a progressive reduction of Aire expression and pGE, affecting both Aire-dependent and -independent genes. In contrast, the absence of miR-29a only affected the Aire-dependent gene pool. These findings reveal a mutual interdependence of miRNA and Aire. © 2013 The Authors. European Journal of Immunology published byWiley-VCH Verlag GmbH & Co. KGaA Weinheim.

  13. Development of Micro Air Reconnaissance Vehicle as a Test Bed for Advanced Sensors and Electronics

    Science.gov (United States)

    Shams, Qamar A.; Vranas, Thomas L.; Fox, Robert L.; Kuhn, Theodore R.; Ingham, John; Logan, Michael J.; Barnes, Kevin N.; Guenther, Benjamin F.

    2002-01-01

    This paper describes the development of a Micro/Mini Air Reconnaissance Vehicle for advanced sensors and electronics at NASA Langley Research Center over the last year. This vehicle is expected to have a total weight of less than four pounds, a design velocity of 40 mph, an endurance of 15-20 minutes, and a maximum range of 5km. The vehicle has wings that are simple to detach yet retain the correct alignment. The upper fuselage surface has a quick release hatch used to access the interior and also to mount the varying propulsion systems. The sensor suite developed for this vehicle consists of a Pitot-static measurement system for determining air speed, an absolute pressure measurement for determining altitude, magnetic direction measurement, and three orthogonal gyros to determine body angular rates. Swarming GPS-guidance and in-flight maneuvering is discussed, as well as design and installation of some other advance sensors like MEMS microphones, infrared cameras, GPS, humidity sensors, and an ultrasonic sonar sensor. Also low cost, small size, high performance control and navigation system for the Micro Air Vehicle is discussed. At the end, laboratory characterization of different sensors, motors, propellers, and batteries will be discussed.

  14. Flexibility, stroke, and dimensionless parameters: the importance of telling the whole story for swimming micro-organisms in complex fluids

    Science.gov (United States)

    Thomases, Becca; Guy, Robert

    2015-11-01

    The question of how fluid elasticity affects the swimming performance of micro-organisms is complicated and has been the subject of many recent experimental and theoretical studies. The Deborah number, De = λω , is typically used to characterize the strength of the fluid elasticity in these studies, and for swimmers is expressed as the product of the elastic relaxation time and the frequency of the swimmer stroke. In simulations of undulatory flexible swimmers in an Oldroyd-B-type fluid, we find that varying the frequency of the stroke and varying the relaxation time separately results in a significantly different dependence of swimming speed for the same De . Thus the elastic effects on swimming cannot be characterized by a single dimensionless number. The Weissenberg number, defined as the product of elastic relaxation time and characteristic strain rate (Wi = λγ˙), is another dimensionless parameter useful for describing complex fluids. For a fixed swimmer frequency, varying the relaxation time will also vary the Weissenberg number. We conjecture that the different behavior is a consequence of a Weissenberg-number transition in the fluid, which additionally depends on the amplitude of the swimmer stroke.

  15. A micro-gap, air-filled ionisation chamber as a detector for criticality accident dosimetry.

    Science.gov (United States)

    Murawski, Ł; Zielczyński, M; Golnik, N; Gryziński, M A

    2014-10-01

    A micro-gap air-filled ionisation chamber was designed for criticality dosimetry. The special feature of the chamber is its very small gap between electrodes of only 0.3 mm. This prevents ion recombination at high dose rates and minimises the influence of gas on secondary particles spectrum. The electrodes are made of polypropylene because of higher content of hydrogen in this material, when compared with soft tissue. The difference between neutron and gamma sensitivity in such chamber becomes practically negligible. The chamber's envelope contains two specially connected capacitors, one for polarising the electrodes and the other for collecting the ionisation charge.

  16. High–Precise Micro Bonding Process using a Focused Stream of Hot Air

    DEFF Research Database (Denmark)

    Andrijasevic, Daniela; Bissacco, Giuliano; Giouroudi, I.

    2006-01-01

    This paper discusses a new approach to adhesive microbonding which can overcome restrictions or drawbacks of the conventional MEMS bonding techniques. The main advantages of this technique are: low process temperature, multi material applicability, partial reversibility and partial biocompatibility....... In proposed technique, the adhesive is deposited on the substrate and the micro-component is brought and placed at the requested position. Afterwards, the stream of hot air is applied in order to soften the glue and to emboss the micropart. After cooling down at room temperature, the glue hardens and final...... bond is achieved....

  17. Impurity intrusion in radio-frequency micro-plasma jets operated in ambient air

    CERN Document Server

    Niermann, B; Böke, M; Winter, J

    2011-01-01

    Space and time resolved concentrations of helium metastable atoms in an atmospheric pressure radio-frequency micro-plasma jet were measured using tunable diode laser absorption spectroscopy. Spatial profiles as well as lifetime measurements show significant influences of air entering the discharge from the front nozzle and of impurities originating from the gas supply system. Quenching of metastables was used to deduce quantitative concentrations of intruding impurities. The impurity profile along the jet axis was determined from optical emission spectroscopy as well as their dependance on the feed gas flow through the jet.

  18. Rolling-based direct-transfer printing: A process for large-area transfer of micro- and nanostructures onto flexible substrates

    Science.gov (United States)

    Grierson, D. S.; Flack, F. S.; Lagally, M. G.; Turner, K. T.

    2016-09-01

    A rolling-based printing approach for transferring arrays of patterned micro- and nano-structures directly from rigid fabrication substrates onto flexible substrates is presented. Transfer-printing experiments show that the new process can achieve high-yield and high-fidelity transfer of silicon nanomembrane components with diverse architectures to polyethylene terephthalate substrates over chip-scale areas (>1 × 1 cm2) in process are investigated through finite element simulations of the contact and transfer process. These mechanics models provide guidance for controlling the contact area and strain in the flexible substrate during transfer, both of which are key for achieving reproducible and controlled component transfer over large areas.

  19. Internal air flow analysis of a bladeless micro aerial vehicle hemisphere body using computational fluid dynamic

    Energy Technology Data Exchange (ETDEWEB)

    Othman, M. N. K., E-mail: najibkhir86@gmail.com, E-mail: zuradzman@unimap.edu.my, E-mail: hazry@unimap.edu.my, E-mail: khairunizam@unimap.edu.my, E-mail: shahriman@unimap.edu.my, E-mail: s.yaacob@unimap.edu.my, E-mail: syedfaiz@unimap.edu.my, E-mail: abadal@unimap.edu.my; Zuradzman, M. Razlan, E-mail: najibkhir86@gmail.com, E-mail: zuradzman@unimap.edu.my, E-mail: hazry@unimap.edu.my, E-mail: khairunizam@unimap.edu.my, E-mail: shahriman@unimap.edu.my, E-mail: s.yaacob@unimap.edu.my, E-mail: syedfaiz@unimap.edu.my, E-mail: abadal@unimap.edu.my; Hazry, D., E-mail: najibkhir86@gmail.com, E-mail: zuradzman@unimap.edu.my, E-mail: hazry@unimap.edu.my, E-mail: khairunizam@unimap.edu.my, E-mail: shahriman@unimap.edu.my, E-mail: s.yaacob@unimap.edu.my, E-mail: syedfaiz@unimap.edu.my, E-mail: abadal@unimap.edu.my; Khairunizam, Wan, E-mail: najibkhir86@gmail.com, E-mail: zuradzman@unimap.edu.my, E-mail: hazry@unimap.edu.my, E-mail: khairunizam@unimap.edu.my, E-mail: shahriman@unimap.edu.my, E-mail: s.yaacob@unimap.edu.my, E-mail: syedfaiz@unimap.edu.my, E-mail: abadal@unimap.edu.my; Shahriman, A. B., E-mail: najibkhir86@gmail.com, E-mail: zuradzman@unimap.edu.my, E-mail: hazry@unimap.edu.my, E-mail: khairunizam@unimap.edu.my, E-mail: shahriman@unimap.edu.my, E-mail: s.yaacob@unimap.edu.my, E-mail: syedfaiz@unimap.edu.my, E-mail: abadal@unimap.edu.my; Yaacob, S., E-mail: najibkhir86@gmail.com, E-mail: zuradzman@unimap.edu.my, E-mail: hazry@unimap.edu.my, E-mail: khairunizam@unimap.edu.my, E-mail: shahriman@unimap.edu.my, E-mail: s.yaacob@unimap.edu.my, E-mail: syedfaiz@unimap.edu.my, E-mail: abadal@unimap.edu.my; Ahmed, S. Faiz, E-mail: najibkhir86@gmail.com, E-mail: zuradzman@unimap.edu.my, E-mail: hazry@unimap.edu.my, E-mail: khairunizam@unimap.edu.my, E-mail: shahriman@unimap.edu.my, E-mail: s.yaacob@unimap.edu.my, E-mail: syedfaiz@unimap.edu.my, E-mail: abadal@unimap.edu.my [Centre of Excellence for Unmanned Aerial Systems, Universiti Malaysia Perlis, 01000 Kangar, Perlis (Malaysia); and others

    2014-12-04

    This paper explain the analysis of internal air flow velocity of a bladeless vertical takeoff and landing (VTOL) Micro Aerial Vehicle (MAV) hemisphere body. In mechanical design, before produce a prototype model, several analyses should be done to ensure the product's effectiveness and efficiency. There are two types of analysis method can be done in mechanical design; mathematical modeling and computational fluid dynamic. In this analysis, I used computational fluid dynamic (CFD) by using SolidWorks Flow Simulation software. The idea came through to overcome the problem of ordinary quadrotor UAV which has larger size due to using four rotors and the propellers are exposed to environment. The bladeless MAV body is designed to protect all electronic parts, which means it can be used in rainy condition. It also has been made to increase the thrust produced by the ducted propeller compare to exposed propeller. From the analysis result, the air flow velocity at the ducted area increased to twice the inlet air. This means that the duct contribute to the increasing of air velocity.

  20. Internal air flow analysis of a bladeless micro aerial vehicle hemisphere body using computational fluid dynamic

    Science.gov (United States)

    Othman, M. N. K.; Zuradzman, M. Razlan; Hazry, D.; Khairunizam, Wan; Shahriman, A. B.; Yaacob, S.; Ahmed, S. Faiz; Hussain, Abadalsalam T.

    2014-12-01

    This paper explain the analysis of internal air flow velocity of a bladeless vertical takeoff and landing (VTOL) Micro Aerial Vehicle (MAV) hemisphere body. In mechanical design, before produce a prototype model, several analyses should be done to ensure the product's effectiveness and efficiency. There are two types of analysis method can be done in mechanical design; mathematical modeling and computational fluid dynamic. In this analysis, I used computational fluid dynamic (CFD) by using SolidWorks Flow Simulation software. The idea came through to overcome the problem of ordinary quadrotor UAV which has larger size due to using four rotors and the propellers are exposed to environment. The bladeless MAV body is designed to protect all electronic parts, which means it can be used in rainy condition. It also has been made to increase the thrust produced by the ducted propeller compare to exposed propeller. From the analysis result, the air flow velocity at the ducted area increased to twice the inlet air. This means that the duct contribute to the increasing of air velocity.

  1. Central-wavelength-tunable multi-wavelength fiber laser based on micro-air gap cavity and tapered fiber structure

    Science.gov (United States)

    Chen, Jiao; Tong, Zhengrong; Yang, He; Zhang, Weihua; Xue, Lifang; Pan, Honggang

    2017-08-01

    A multi-wavelength erbium-doped fiber laser based on a micro-air gap cavity filter and the tapered fiber structure is proposed and demonstrated. The micro-air gap cavity filter is constructed by aligning two polished single mode fiber facets carefully through a capillary. Then a tapered fiber structure is applied to compose a cascaded filter with the micro-air gap cavity filter. According to the experiment, the transmission spectrum of the tapered fiber structure acts as the outer envelope of the cascaded structure, which is used as a tunable filter. Moreover, the periodically localized peaks of the tapered fiber structure are modulated by sinusoidal spectral response of the micro-air gap cavity filter. And the micro-air gap cavity filter acts as a comb filter, which determines the channel space of the cascaded filter structure. By using the above superimposed filter, four wavelengths with a wavelength spacing of about 1.20 nm are generated under the pump power of 270 mW. The side-mode suppression ratio of all lasing wavelengths is about 35 dB. The tapered fiber structure is fixed on a furnace, when the temperature varies from 30 °C to 120 °C, the first wavelength can be tuned within the range of 5.31 nm.

  2. Autoimmune regulator (Aire) controls the expression of microRNAs in medullary thymic epithelial cells.

    Science.gov (United States)

    Macedo, Claudia; Evangelista, Adriane F; Marques, Márcia M; Octacílio-Silva, Shirlei; Donadi, Eduardo A; Sakamoto-Hojo, Elza T; Passos, Geraldo A

    2013-04-01

    The autoimmune regulator (Aire) is a transcription factor that controls the ectopic expression of a large set of peripheral tissue antigen (PTA) genes in medullary thymic epithelial cells (mTECs). Recent evidence has demonstrated that Aire releases stalled RNA polymerase II (RNA Pol II) from blockage at the promoter region of its target genes. Given that, in addition to messenger RNAs (mRNA), RNA Pol II also transcribes microRNAs (miRNAs), we raised the hypothesis that Aire might play a role as an upstream controller of miRNA transcription. To test this, we initially analyzed the expression profiles of 662 miRNAs in control and Aire-silenced (siRNA) murine mTEC 3.10 cells using microarrays. The bioinformatics programs SAM and Cluster-TreeView were then used to identify the differentially expressed miRNAs and their profiles, respectively. Thirty Aire-dependent miRNAs were identified in the Aire-silenced mTECs, of which 18 were up- and 12 were down-regulated. The down-regulated miR-376 family was the focus of this study because its members (miR-376a, miR-376b and miR-376c) are located in the genome within the Gm2922 open-reading frame (ORF) gene segment on the chromosome 12F1. The T-boxes (TTATTA) and G-boxes (GATTGG), which represent putative RNA Pol II promoter motifs, were located in a portion spanning 10 kb upstream of the ATG codon of Gm2922. Moreover, we found that Gm2922 encodes an mRNA, which was also down-regulated in Aire-silenced mTECs. These results represent the first evidence that Aire can play a role as a controller of transcription of miRNAs located within genomic regions encompassing ORF and/or mRNA genes. Copyright © 2012 Elsevier GmbH. All rights reserved.

  3. Theoretical Investigation on Particle Brownian Motion on Micro-air-bubble Characteristic in H2O Solvent

    Science.gov (United States)

    Eka Putri, Irana; Gita Redhyka, Grace

    2017-07-01

    Micro-air-bubble has a high potential contribution in waste water, farming, and fishery treatment. In this research, submicron scale of micro-air-bubble was observed to determine its stability in H2O solvent. By increasing its stability, it can be used for several applications, such as bio-preservative for medical and food transport. The micro-air-bubble was assumed in spherical shape that in incompressible gas boundary condition. So, the random motion of particle (Brownian motion) can be solved by using Stokes-Einstein approximation. But, Hadamard and Rybczynski equation is promoted to solve for larger bubble (micro scale). While, the effect of physical properties (e.g. diffusion coefficient, density, and flow rate) have taken important role in its characteristics in water. According to the theoretical investigation that have been done, decreasing of bubble velocity indicates that the bubble dissolves away or shrinking to the surface. To obtain longevity bubble in pure water medium, it is recomended to apply some surfactant molecules (e.g. NaCl) in micro-air-bubble medium.

  4. FANTASTIC-5G: flexible air interface for scalable service delivery within wireless communication networks of the 5th generation

    DEFF Research Database (Denmark)

    Schaich, Frank; Sayrac, Berna; Elayoubi, Salaheddine

    2016-01-01

    5th generation mobile networks will have to cope with a high degree of heterogeneity in terms of services, mobility, number of devices and so on. Thus, diverse and often contradicting key performance indicators need to be supported, but having multiple radio access technologies for multi-service...... support below 6 GHz will be too costly. FANTASTIC-5G will develop a new multi-service air interface through a modular design. To allow the system to adapt to the anticipated heterogeneity, some properties need to be pursued, like simplicity, flexibility, scalability, versatility, efficiency and future...

  5. Influence of turbulent flow on the explosion parameters of micro- and nano-aluminum powder-air mixtures.

    Science.gov (United States)

    Liu, Xueling; Zhang, Qi

    2015-12-15

    The environmental turbulence intensity has a significant influence on the explosion parameters of both micro- and nano-Al at the time of ignition. However, explosion research on turbulence intensity with respect to micro- and nano-Al powders is still insufficient. In this work, micro- and nano-aluminum powders were investigated via scanning electron microscopy (SEM), and their particle size distributions were measured using a laser diffraction analyzer under dispersing air pressures of 0.4, 0.6, and 0.8 MPa in a 20 L cylindrical, strong plexiglass vessel. The particle size distributions in three different mass ratio mixtures of micro- and nano-Al powders (micro-Al:nano-Al[massratio]=95:5, 90:10, and 85:15) were also measured. The results show that the agglomerate size of nano-Al powder is an order of magnitude larger than the nanoparticles' actual size. Furthermore, the turbulence intensity ranges (Urms) of the Al powder-air mixtures were measured using particle image velocimetry (PIV) under dispersing air pressures of 0.4, 0.6, and 0.8 MPa. The effect of turbulence intensity on the explosion characteristics of the micro- and nano-Al powders was investigated using a 20 L cylindrical explosion vessel. The results of micro-Al and nano-Al powder-air mixtures with a stoichiometric concentration of 337.00 g·m(-3) were discussed for the maximum explosion pressure, the maximum rate of pressure increase and the maximum effective burning velocity under the different turbulence intensity.

  6. Real-Time Fixed-Order Lateral H2 Controller for Micro Air Vehicle

    Directory of Open Access Journals (Sweden)

    Meenakshi M.

    2011-01-01

    Full Text Available This paper presents the design and development of a fixed low-order, robust H2 controller for a micro air vehicle (MAV named Sarika-2. The controller synthesis uses strengthened discrete optimal projection equations and frequency-dependent performance index to achieve robust performance and stability. A single fixed gain low-order dynamic controller provides simultaneous stabilization, disturbance rejection, and sensor noise attenuation over the entire flight speed range of 16 m/sec to 26 m/sec. Comparative study indicates that the low-order H2-controller achieves robust performance levels similar to that of full order controller. Subsequently, the controller is implemented on a digital signal processor-based flight computer and is validated through the real time hardware in loop simulation. The responses obtained with hardware in loop simulation compares well with those obtained from the offline simulation.

  7. Towards micro-arcsecond spatial resolution with Air Cherenkov Telescope arrays as optical intensity interferometers

    CERN Document Server

    De Wit, W J; Hinton, J A; White, R J; Daniel, M K; Holder, J

    2008-01-01

    In this poster contribution we highlight the equivalence between an Imaging Air Cherenkov Telescope (IACT) array and an Intensity Interferometer for a range of technical requirements. We touch on the differences between a Michelson and an Intensity Interferometer and give a brief overview of the current IACT arrays, their upgrades and next generation concepts (CTA, AGIS, completion 2015). The latter are foreseen to include 30-90 telescopes that will provide 400-4000 different baselines that range in length between 50m and a kilometre. Intensity interferometry with such arrays of telescopes attains 50 micro-arcseconds resolution for a limiting V magnitude of ~8.5. This technique opens the possibility of a wide range of studies, amongst others, probing the stellar surface activity and the dynamic AU scale circumstellar environment of stars in various crucial evolutionary stages. Here we discuss possibilities for using IACT arrays as optical Intensity Interferometers.

  8. Design of a Six-link Mechanism for a Micro Air Vehicle

    Directory of Open Access Journals (Sweden)

    S. Mukherjee

    2004-07-01

    Full Text Available Micro air vehicle (MAV is a small flight vehicle that uses lift-generating mechanism different from the mechanism used for a larger aircraft. The MAV may require configurations that are more unusual and approaches, ranging from low aspect ratio fixed wings to rotary wings, or even flapping wings. One of the most efficient lift-generating mechanism in small geometries is observed in the one species of insects Encarsia formosa, as reported by Weis Fogh. This is achieved by generating lift prior to setting up of net circulation. In this paper, the design of a flapping mechanism used to realise the Weis Fogh mechanism of lift generation is described. A single-drive design using concepts of motion synthesis by kinematic inversion technique, followed by dynamic analysis, is presented. This simplification opens the way for future miniaturisation of these devices at economic costs.

  9. INTEGRATED USE OF RAPID PROTOTYPING AND METAL PLATING TECHNIQUES FOR DEVELOPMENT OF MICRO AIR VEHICLES

    Directory of Open Access Journals (Sweden)

    Dr. K. ELANGOVAN,

    2011-01-01

    Full Text Available This paper describes the synergistic application of rapid prototyping and metal plating technologies for development of micro air vehicles (MAV with high strength-to-weight characteristic. Stereolithography and fused deposition techniques are employed to fabricate complex thermoplastic MAV prototypes with significant time-compression in production cycle. Electroless and electrolytic deposition processes are custom developed to deposit thin metallic foils of nickel and chromium over thermoplastic MAV prototypes. Plating plant with inherent provision for variation of process parameters is established and proof-of-concept studies are carried on plating of MAV prototypes. Experiments are conducted on metal plated thermoplastic test specimens for evaluating the mechanical behaviour and structural integrity properties. Present study is a conclusive demonstration of the use of layered manufacturing techniques in quick realisation of flight-worthy MAV systems.

  10. A review of compliant transmission mechanisms for bio-inspired flapping-wing micro air vehicles.

    Science.gov (United States)

    Zhang, C; Rossi, C

    2017-02-15

    Flapping-wing micro air vehicles (FWMAVs) are a class of unmanned aircraft that imitate flight characteristics of natural organisms such as birds, bats, and insects, in order to achieve maximum flight efficiency and manoeuvrability. Designing proper mechanisms for flapping transmission is an extremely important aspect for FWMAVs. Compliant transmission mechanisms have been considered as an alternative to rigid transmission systems due to their lower the number of parts, thereby reducing the total weight, lower energy loss thanks to little or practically no friction among parts, and at the same time, being able to store and release mechanical power during the flapping cycle. In this paper, the state-of-the-art research in this field is dealt upon, highlighting open challenges and research topics. An optimization method for designing compliant transmission mechanisms inspired by the thoraxes of insects is also introduced.

  11. Design and mechanical analysis of a 3D-printed biodegradable biomimetic micro air vehicle wing

    Science.gov (United States)

    Salami, E.; Ganesan, P. B.; Ward, T. A.; Viyapuri, R.; Romli, F. I.

    2016-10-01

    The biomimetic micro air vehicles (BMAV) are unmanned, micro-scaled aircraft that are bio-inspired from flying organisms to achieve the lift and thrust by flapping their wings. There are still many technological challenges involved with designing the BMAV. One of these is designing the ultra-lightweight materials and structures for the wings that have enough mechanical strength to withstand continuous flapping at high frequencies. Insects achieve this by having chitin-based, wing frame structures that encompass a thin, film membrane. The main objectives of this study are to design a biodegradable BMAV wing (inspired from the dragonfly) and analyze its mechanical properties. The dragonfly-like wing frame structure was bio-mimicked and fabricated using a 3D printer. A chitosan nanocomposite film membrane was applied to the BMAV wing frames through casting method. Its mechanical performance was analyzed using universal testing machine (UTM). This analysis indicates that the tensile strength and Young's modulus of the wing with a membrane is nearly double that of the wing without a membrane, which allow higher wing beat frequencies and deflections that in turn enable a greater lifting performance.

  12. 4D metrology of flapping-wing micro air vehicle based on fringe projection

    Science.gov (United States)

    Zhang, Qican; Huang, Lei; Chin, Yao-Wei; Keong, Lau-Gih; Asundi, Anand

    2013-06-01

    Inspired by dominant flight of the natural flyers and driven by civilian and military purposes, micro air vehicle (MAV) has been developed so far by passive wing control but still pales in aerodynamic performance. Better understanding of flapping wing flight mechanism is eager to improve MAV's flight performance. In this paper, a simple and effective 4D metrology technique to measure full-field deformation of flapping membrane wing is presented. Based on fringe projection and 3D Fourier analysis, the fast and complex dynamic deformation, including wing rotation and wing stroke, of a flapping wing during its flight can be accurately reconstructed from the deformed fringe patterns recorded by a highspeed camera. An experiment was carried on a flapping-wing MAV with 5-cm span membrane wing beating at 30 Hz, and the results show that this method is effective and will be useful to the aerodynamicist or micro aircraft designer for visualizing high-speed complex wing deformation and consequently aid the design of flapping wing mechanism to enhanced aerodynamic performance.

  13. The Influence of Slight Protuberances in a Micro-Tube Reactor on Methane/Moist Air Catalytic Combustion

    Directory of Open Access Journals (Sweden)

    Ruirui Wang

    2016-05-01

    Full Text Available The combustion characteristics of methane/moist air in micro-tube reactors with different numbers and shapes of inner wall protuberances are investigated in this paper. The micro-reactor with one rectangular protuberance (six different sizes was studied firstly, and it is shown that reactions near the protuberance are mainly controlled by diffusion, which has little effect on the outlet temperature and methane conversion rate. The formation of cavities and recirculation zones in the vicinity of protuberances leads to a significant increase of the Arrhenius reaction rate of CH4 and gas velocity. Next, among the six different simulated conditions (0–5 rectangular protuberances, the micro-tube reactor with five rectangular protuberances shows the highest methane conversion rate. Finally, the effect of protuberance shape on methane/moist air catalytic combustion is confirmed, and it is found that the protuberance shape has a greater influence on methane conversion rate than the number of protuberances. The methane conversion rate in the micro-tube decreases progressively in the following order: five triangular slight protuberances > five rectangular protuberances > five trapezoidal protuberances > smooth tube. In all tests of methane/moist air combustion conditions, the micro-tube with five triangular protuberances has the peak efficiency and is therefore recommended for high efficiency reactors.

  14. Air microjet system for non-contact force application and the actuation of micro-structures

    Science.gov (United States)

    Khare, S. M.; Venkataraman, V.

    2016-01-01

    We demonstrate a non-contact technique to apply calibrated and localized forces in the micro-Newton to milli-Newton range using an air microjet. An electromagnetically actuated diaphragm controlled by a signal generator is used to generate the air microjet. With a nozzle diameter of 150 μm, the microjet diameter was maintained to a maximum of 1 mm at a distance of 5 mm from the nozzle. The force generated by the microjet was measured using a commercial force sensor to determine the velocity profile of the jet. Axial flow velocities of up to 25 m s-1 were obtained at distances as long as 6 mm. The microjet exerted a force up to 1 μN on a poly dimethyl siloxane (PDMS) micropillar (50 μm in diameter, 157 μm in height) and 415 μN on a PDMS membrane (3 mm in diameter, 28 μm thick). We also demonstrate that from a distance of 6 mm our microjet can exert a peak pressure of 187 Pa with a total force of about 84 μN on a flat surface with 8 V operating voltage. Out of the cleanroom fabrication and robust design make this system cost effective and durable.

  15. Flexible Lamination-Fabricated Ultra-High Frequency Diodes Based on Self-Supporting Semiconducting Composite Film of Silicon Micro-Particles and Nano-Fibrillated Cellulose

    Science.gov (United States)

    Sani, Negar; Wang, Xin; Granberg, Hjalmar; Andersson Ersman, Peter; Crispin, Xavier; Dyreklev, Peter; Engquist, Isak; Gustafsson, Göran; Berggren, Magnus

    2016-06-01

    Low cost and flexible devices such as wearable electronics, e-labels and distributed sensors will make the future “internet of things” viable. To power and communicate with such systems, high frequency rectifiers are crucial components. We present a simple method to manufacture flexible diodes, operating at GHz frequencies, based on self-adhesive composite films of silicon micro-particles (Si-μPs) and glycerol dispersed in nanofibrillated cellulose (NFC). NFC, Si-μPs and glycerol are mixed in a water suspension, forming a self-supporting nanocellulose-silicon composite film after drying. This film is cut and laminated between a flexible pre-patterned Al bottom electrode and a conductive Ni-coated carbon tape top contact. A Schottky junction is established between the Al electrode and the Si-μPs. The resulting flexible diodes show current levels on the order of mA for an area of 2 mm2, a current rectification ratio up to 4 × 103 between 1 and 2 V bias and a cut-off frequency of 1.8 GHz. Energy harvesting experiments have been demonstrated using resistors as the load at 900 MHz and 1.8 GHz. The diode stack can be delaminated away from the Al electrode and then later on be transferred and reconfigured to another substrate. This provides us with reconfigurable GHz-operating diode circuits.

  16. Flexible Lamination-Fabricated Ultra-High Frequency Diodes Based on Self-Supporting Semiconducting Composite Film of Silicon Micro-Particles and Nano-Fibrillated Cellulose.

    Science.gov (United States)

    Sani, Negar; Wang, Xin; Granberg, Hjalmar; Andersson Ersman, Peter; Crispin, Xavier; Dyreklev, Peter; Engquist, Isak; Gustafsson, Göran; Berggren, Magnus

    2016-01-01

    Low cost and flexible devices such as wearable electronics, e-labels and distributed sensors will make the future "internet of things" viable. To power and communicate with such systems, high frequency rectifiers are crucial components. We present a simple method to manufacture flexible diodes, operating at GHz frequencies, based on self-adhesive composite films of silicon micro-particles (Si-μPs) and glycerol dispersed in nanofibrillated cellulose (NFC). NFC, Si-μPs and glycerol are mixed in a water suspension, forming a self-supporting nanocellulose-silicon composite film after drying. This film is cut and laminated between a flexible pre-patterned Al bottom electrode and a conductive Ni-coated carbon tape top contact. A Schottky junction is established between the Al electrode and the Si-μPs. The resulting flexible diodes show current levels on the order of mA for an area of 2 mm(2), a current rectification ratio up to 4 × 10(3) between 1 and 2 V bias and a cut-off frequency of 1.8 GHz. Energy harvesting experiments have been demonstrated using resistors as the load at 900 MHz and 1.8 GHz. The diode stack can be delaminated away from the Al electrode and then later on be transferred and reconfigured to another substrate. This provides us with reconfigurable GHz-operating diode circuits.

  17. Research on characteristics of water motion and influencing factors for the flexible air chamber jig body

    Institute of Scientific and Technical Information of China (English)

    Chen Yinghua; Kuang Yali; Li Haisheng

    2015-01-01

    The air bag deformation data were obtained by high-speed dynamic videos experiments. Based on gas–liquid flow VOF model, dynamic mesh technique and deformation data, numerical simulations for differ-ent structure models were achieved, and the law of water motion and influencing factors were analyzed. The results show that the flow in the length direction of the jig is smooth, and second pulsation appears in the separation time and forms the secondary separation. The installation position of screen and the num-ber of air bags have a great influence on the uniformity of flow and velocity. The screen height cannot be too low to avoid forming the unstable flow. At the same time, the screen height cannot be too high, other-wise water velocity will be too small and was unable to provide enough power. At the height of 1.4 m, velocity unevenness is minimum and the best uniform flow can be obtained. Compared with double air bags, there are the following features of single air bag:water flow is not smooth, the time achieving the maximum velocity is too long, maximum velocity is smaller, and overall effect is worse than double air bags.

  18. High Performance All-Solid-State Flexible Micro-Pseudocapacitor Based on Hierarchically Nanostructured Tungsten Trioxide Composite.

    Science.gov (United States)

    Huang, Xuezhen; Liu, Hewei; Zhang, Xi; Jiang, Hongrui

    2015-12-23

    Microsupercapacitors (MSCs) are promising energy storage devices to power miniaturized portable electronics and microelectromechanical systems. With the increasing attention on all-solid-state flexible supercapacitors, new strategies for high-performance flexible MSCs are highly desired. Here, we demonstrate all-solid-state, flexible micropseudocapacitors via direct laser patterning on crack-free, flexible WO3/polyvinylidene fluoride (PVDF)/multiwalled carbon nanotubes (MWCNTs) composites containing high levels of porous hierarchically structured WO3 nanomaterials (up to 50 wt %) and limited binder (PVDF, work leads to an areal capacitance of 62.4 mF·cm(-2) and a volumetric capacitance of 10.4 F·cm(-3), exceeding that of graphene based flexible MSCs by a factor of 26 and 3, respectively. As a noncarbon based flexible MSC, hierarchically nanostructured WO3 in the narrow finger electrode is essential to such enhancement in energy density due to its pseudocapacitive property. The effects of WO3/PVDF/MWCNTs composite composition and the dimensions of interdigital structure on the performance of the flexible MSCs are investigated.

  19. Advanced air staging techniques to improve fuel flexibility, reliability and emissions in fluidized bed co-combustion

    Energy Technology Data Exchange (ETDEWEB)

    Aamand, Lars-Erik; Leckner, Bo [Chalmers Technical Univ., Goeteborg (Sweden); Luecke, Karsten; Werther, Joachim [Technical Univ. of Hamburg-Harburg (Germany)

    2001-12-01

    A joint research project between the Technical University of Hamburg-Harburg and Chalmers Technical University. For operation under co-combustion the following results should be considered: The high ash content of the sewage sludge results in significantly increased ash flows. Although high alkali metal concentrations are found in the sewage sludge ash, no critical concentrations were reached and tendencies to fouling were not observed. The trace metal input rises with increased sludge fraction. However, emissions of metal compounds were well below legal limits. The trace metals tend to accumulate on the fly ash. In general, very low fuel nitrogen conversions to NO and N{sub 2}O of 2 - 4 % are achievable. With coal as a base fuel alternative air staging with secondary air supply after solids separation attains even lower NO emissions than normal staging without strongly affecting CO and SO{sub 2} emissions. Alternative staging also reduces N{sub 2}O emissions. An optimum for the excess air ratio in the riser of 1.05 was found for a total excess air ratio of 1.2. The higher the volatile content of the fuel is, the less effective the NO reduction due to air staging becomes. The measurements suggest that the optimum gas residence time regarding the emissions in CFB combustors is around 6 to 7 s. These times are achieved in commercial scale plants due to their large cyclones that perhaps partly can replace a large afterburner chamber. The circulating fluidized bed boiler can be operated in a very flexible way with various fuel mixtures up to an energy fraction of sludge of 25% without exceeding legal emission limits.

  20. Adaptive fuzzy tracking control for a constrained flexible air-breathing hypersonic vehicle based on actuator compensation

    Directory of Open Access Journals (Sweden)

    Peng Fei Wang

    2016-10-01

    Full Text Available The design of an adaptive fuzzy tracking control for a flexible air-breathing hypersonic vehicle with actuator constraints is discussed. Based on functional decomposition methodology, velocity and altitude controllers are designed. Fuzzy logic systems are applied to approximate the lumped uncertainty of each subsystem of air-breathing hypersonic vehicle model. Every controllers contain only one adaptive parameter that needs to be updated online with a minimal-learning-parameter scheme. The back-stepping design is not demanded by converting the altitude subsystem into the normal output-feedback formulation, which predigests the design of a controller. The special contribution is that novel auxiliary systems are developed to compensate both the tracking errors and desired control laws, based on which the explored controller can still provide effective tracking of velocity and altitude commands when the inputs are saturated. Finally, reference trajectory tracking simulation shows the effectiveness of the proposed method in its application to air-breathing hypersonic vehicle control.

  1. A flexible and low cost experimental stand for air source heat pump for Smart Buildings

    DEFF Research Database (Denmark)

    Crăciun, Vasile S.; Bojesen, Carsten; Blarke, Morten

    2012-01-01

    prices. A significant part of this challenge may be dealt with in the way space heating, space cooling, and domestic hot water production which is provided to residential and commercial buildings. Air source heat pumps (ASHP) are widely used conversion technologies for providing building thermal energy...

  2. Novel design of a disk-shaped compacted micro-structured air-breathing PEM fuel cell

    Directory of Open Access Journals (Sweden)

    Maher A.R. Sadiq Al-Baghdadi

    2012-01-01

    Full Text Available The presence of microelectromechanical system (MEMS technology makes it possible to manufacture the miniaturized fuel cell systems for application in portable electronic devices. The majority of research on micro-scale fuel cells is aimed at micro-power applications. There are many new miniaturized applications which can only be realized if a higher energy density power source is available compared to button cells and other small batteries. In small-scale applications, the fuel cell should be exceptionally small and have highest energy density. One way to achieve these requirements is to reduce the thickness of the cell (compacted-design for increasing the volumetric power density of a fuel cell power supply. A novel, simple to construct, air-breathing micro-structured PEM fuel cell which work in still or slowly moving air has been developed. The novel geometry enables optimum air access to the cathode without the need for pumps, fans or similar devices. In addition, the new design can achieve much higher active area to volume ratios, and hence higher volumetric power densities. Three-dimensional, multi-phase, non-isothermal CFD model of this novel design has been developed. This comprehensive model account for the major transport phenomena in an air-breathing micro-structured PEM fuel cell: convective and diffusive heat and mass transfer, electrode kinetics, transport and phase-change mechanism of water, and potential fields. The model is shown to understand the many interacting, complex electrochemical, and transport phenomena that cannot be studied experimentally. Fully three-dimensional results of the species profiles, temperature distribution, potential distribution, and local current density distribution are presented and analyzed with a focus on the physical insight and fundamental understanding. They can provide a solid basis for optimizing the geometry of the PEM micro fuel cell stack running with a passive mode.

  3. Multi-sensor fusion techniques for state estimation of micro air vehicles

    Science.gov (United States)

    Donavanik, Daniel; Hardt-Stremayr, Alexander; Gremillion, Gregory; Weiss, Stephan; Nothwang, William

    2016-05-01

    Aggressive flight of micro air vehicles (MAVs) in unstructured, GPS-denied environments poses unique challenges for estimation of vehicle pose and velocity due to the noise, delay, and drift in individual sensor measurements. Maneuvering flight at speeds in excess of 5 m/s poses additional challenges even for active range sensors; in the case of LIDAR, an assembled scan of the vehicles environment will in most cases be obsolete by the time it is processed. Multi-sensor fusion techniques which combine inertial measurements with passive vision techniques and/or LIDAR have achieved breakthroughs in the ability to maintain accurate state estimates without the use of external positioning sensors. In this paper, we survey algorithmic approaches to exploiting sensors with a wide range of nonlinear dynamics using filter and bundle-adjustment based approaches for state estimation and optimal control. From this foundation, we propose a biologically-inspired framework for incorporating the human operator in the loop as a privileged sensor in a combined human/autonomy paradigm.

  4. Stereo vision-based obstacle avoidance for micro air vehicles using an egocylindrical image space representation

    Science.gov (United States)

    Brockers, R.; Fragoso, A.; Matthies, L.

    2016-05-01

    Micro air vehicles which operate autonomously at low altitude in cluttered environments require a method for onboard obstacle avoidance for safe operation. Previous methods deploy either purely reactive approaches, mapping low-level visual features directly to actuator inputs to maneuver the vehicle around the obstacle, or deliberative methods that use on-board 3-D sensors to create a 3-D, voxel-based world model, which is then used to generate collision free 3-D trajectories. In this paper, we use forward-looking stereo vision with a large horizontal and vertical field of view and project range from stereo into a novel robot-centered, cylindrical, inverse range map we call an egocylinder. With this implementation we reduce the complexity of our world representation from a 3D map to a 2.5D image-space representation, which supports very efficient motion planning and collision checking, and allows to implement configuration space expansion as an image processing function directly on the egocylinder. Deploying a fast reactive motion planner directly on the configuration space expanded egocylinder image, we demonstrate the effectiveness of this new approach experimentally in an indoor environment.

  5. Enhanced cooling in mono-crystalline ultra-thin silicon by embedded micro-air channels

    KAUST Repository

    Ghoneim, Mohamed T.

    2015-12-11

    In today’s digital world, complementary metal oxide semiconductor (CMOS) technology enabled scaling of bulk mono-crystalline silicon (100) based electronics has resulted in their higher performance but with increased dynamic and off-state power consumption. Such trade-off has caused excessive heat generation which eventually drains the charge of battery in portable devices. The traditional solution utilizing off-chip fans and heat sinks used for heat management make the whole system bulky and less mobile. Here we show, an enhanced cooling phenomenon in ultra-thin (>10 μm) mono-crystalline (100) silicon (detached from bulk substrate) by utilizing deterministic pattern of porous network of vertical “through silicon” micro-air channels that offer remarkable heat and weight management for ultra-mobile electronics, in a cost effective way with 20× reduction in substrate weight and a 12% lower maximum temperature at sustained loads. We also show the effectiveness of this event in functional MOS field effect transistors (MOSFETs) with high-κ/metal gate stacks.

  6. Drag Reduction of Turbulence Air Channel Flow with Distributed Micro Sensors and Actuators

    Science.gov (United States)

    Yoshino, Takashi; Suzuki, Yuji; Kasagi, Nobuhide

    A prototype system for feedback control of wall turbulence is developed, and its performance is evaluated in a physical experiment. Arrayed micro hot-film sensors with a spanwise spacing of 1 mm are employed for the measurement of streamwise shear stress fluctuations, while arrayed magnetic actuators of 2.4 mm in spanwise width are used to introduce control input through wall deformation. A digital signal processor with a time delay of 0.1 ms is employed to drive the actuators based on the sensor signals. The driving voltage of each actuator is determined with a linear combination of the wall shear stress fluctuations at three sensors located upstream of the actuator, and a noise-tolerant genetic algorithm is employed to optimize the control parameters. Feedback control experiments are conducted in a fully-developed turbulent air channel flow at the Reynolds number of Reτ=300. It is found that about 6% drag reduction has been achieved in a physical experiment for the first time. Through turbulent statistics measurements with LDV, it is also found that the Reynolds shear stress close to the wall is decreased by the present control scheme. A conditional average of a DNS database is also made to extract coherent structures associated with the present control input. It is shown that the wall-deformation actuators induce a wall-normal velocity away from the wall when the high-speed region is located above the actuator.

  7. Enhanced cooling in mono-crystalline ultra-thin silicon by embedded micro-air channels

    Science.gov (United States)

    Ghoneim, Mohamed T.; Fahad, Hossain M.; Hussain, Aftab M.; Rojas, Jhonathan P.; Torres Sevilla, Galo A.; Alfaraj, Nasir; Lizardo, Ernesto B.; Hussain, Muhammad M.

    2015-12-01

    In today's digital world, complementary metal oxide semiconductor (CMOS) technology enabled scaling of bulk mono-crystalline silicon (100) based electronics has resulted in their higher performance but with increased dynamic and off-state power consumption. Such trade-off has caused excessive heat generation which eventually drains the charge of battery in portable devices. The traditional solution utilizing off-chip fans and heat sinks used for heat management make the whole system bulky and less mobile. Here we show, an enhanced cooling phenomenon in ultra-thin (>10 μm) mono-crystalline (100) silicon (detached from bulk substrate) by utilizing deterministic pattern of porous network of vertical "through silicon" micro-air channels that offer remarkable heat and weight management for ultra-mobile electronics, in a cost effective way with 20× reduction in substrate weight and a 12% lower maximum temperature at sustained loads. We also show the effectiveness of this event in functional MOS field effect transistors (MOSFETs) with high-κ/metal gate stacks.

  8. Optical emission spectroscopy characterizations of micro-air plasma used for simulation of cell membrane poration

    Science.gov (United States)

    Zerrouki, A.; Motomura, H.; Ikeda, Y.; Jinno, M.; Yousfi, M.

    2016-07-01

    A micro-air corona discharge, which is one of the plasmas successfully used for gene transfection in terms of high transfection and cell viability rates, is characterized by optical emission spectroscopy. This non-equilibrium low temperature plasma is generated from the tip of a pulsed high voltage micro-tube (0.2 mm inner diameter and 0.7 mm for outer diameter) placed 2 mm in front of a petri dish containing deionized water and set on a grounded copper plate. The electron temperature, equal to about 6.75 eV near the electrode tip and decreased down to 3.4 eV near the plate, has been estimated, with an error bar of about 30%, from an interesting approach based on the experimental ratio of the closest nitrogen emission spectra of \\text{N}2+ (FNS) at 391.4 nm and N2(SPS) at 394.3 nm. This is based on one hand on a balance equation between creations and losses of the excited upper levels of these two UV spectra and on the other hand on the electron impact rates of the creation of these upper levels calculated from solution of the multi-term Boltzmann equation. Then using the measured Hα spectrum, electron density n e has been estimated from Stark broadening versus the inter-electrode position with an average error bar of about 50%. n e  ≈  1  ×  1015 cm-3 is near the tip coherent with the usual magnitude of electron density in the streamer head developed near the tip of the corona discharges. Rotational temperatures, estimated from comparison of synthetic and experimental spectra of OH(A  -  X), \\text{N}2+ (FNS) at 391.4 nm, and N2(SPS) at 337 nm are respectively equal to 2350 K, 2000 K and 700 K in the gap space. This clearly underlines a thermal non-equilibrium of the corresponding excited species generated inside the thin streamer filaments. But, due to the high dilution of these species in the background gas, these high rotational temperatures do not affect the mean gas temperature that remains close to 300

  9. Ground moving target geo-location from monocular camera mounted on a micro air vehicle

    Science.gov (United States)

    Guo, Li; Ang, Haisong; Zheng, Xiangming

    2011-08-01

    The usual approaches to unmanned air vehicle(UAV)-to-ground target geo-location impose some severe constraints to the system, such as stationary objects, accurate geo-reference terrain database, or ground plane assumption. Micro air vehicle(MAV) works with characteristics including low altitude flight, limited payload and onboard sensors' low accuracy. According to these characteristics, a method is developed to determine the location of ground moving target which imaged from the air using monocular camera equipped on MAV. This method eliminates the requirements for terrain database (elevation maps) and altimeters that can provide MAV's and target's altitude. Instead, the proposed method only requires MAV flight status provided by its inherent onboard navigation system which includes inertial measurement unit(IMU) and global position system(GPS). The key is to get accurate information on the altitude of the ground moving target. First, Optical flow method extracts background static feature points. Setting a local region around the target in the current image, The features which are on the same plane with the target in this region are extracted, and are retained as aided features. Then, inverse-velocity method calculates the location of these points by integrated with aircraft status. The altitude of object, which is calculated by using position information of these aided features, combining with aircraft status and image coordinates, geo-locate the target. Meanwhile, a framework with Bayesian estimator is employed to eliminate noise caused by camera, IMU and GPS. Firstly, an extended Kalman filter(EKF) provides a simultaneous localization and mapping solution for the estimation of aircraft states and aided features location which defines the moving target local environment. Secondly, an unscented transformation(UT) method determines the estimated mean and covariance of target location from aircraft states and aided features location, and then exports them for the

  10. Constructed uninterrupted charge-transfer pathways in three-dimensional micro/nanointerconnected carbon-based electrodes for high energy-density ultralight flexible supercapacitors.

    Science.gov (United States)

    He, Yongmin; Chen, Wanjun; Zhou, Jinyuan; Li, Xiaodong; Tang, Pengyi; Zhang, Zhenxing; Fu, Jiecai; Xie, Erqing

    2014-01-08

    A type of freestanding three-dimensional (3D) micro/nanointerconnected structure, with a conjunction of microsized 3D graphene networks, nanosized 3D carbon nanofiber (CNF) forests, and consequently loaded MnO2 nanosheets, has been designed as the electrodes of an ultralight flexible supercapacitor. The resulting 3D graphene/CNFs/MnO2 composite networks exhibit remarkable flexibility and highly mechanical properties due to good and intimate contacts among them, without current collectors and binders. Simultaneously, this designed 3D micro/nanointerconnected structure can provide an uninterrupted double charges freeway network for both electron and electrolyte ion to minimize electron accumulation and ion-diffusing resistance, leading to an excellent electrochemical performance. The ultrahigh specific capacitance of 946 F/g from cyclic voltammetry (CV) (or 920 F/g from galvanostatic charging/discharging (GCD)) were obtained, which is superior to that of the present electrode materials based on 3D graphene/MnO2 hybrid structure (482 F/g). Furthermore, we have also investigated the superior electrochemical performances of an asymmetric supercapacitor device (weight of less than 12 mg/cm(2) and thickness of ~0.8 mm), showing a total capacitance of 0.33 F/cm(2) at a window voltage of 1.8 V and a maximum energy density of 53.4 W h/kg for driving a digital clock for 42 min. These inspiring performances would make our designed supercapacitors become one of the most promising candidates for the future flexible and lightweight energy storage systems.

  11. Three-dimensional study of a one-way, flexible magnetorheological elastomer-based micro fluid transport system

    Science.gov (United States)

    Behrooz, Majid; Gordaninejad, Faramarz

    2016-09-01

    This paper presents a three-dimensional study of a controllable flexible magnetically-activated micropump. The tubular micropump employs magnetically induced deformation of magnetorheological elastomer and one-way flexible conical valves for fluid transport. Three-dimensional magneto-fluid-solid interaction analysis is employed to investigate the performance of the system. The effects of key material, geometric, and magnetic parameters on the effectiveness of the system are examined. It is demonstrated that the proposed system can propel the fluid unidirectionally, and the volume of the transported fluid is significantly affected by some of the design parameters.

  12. Vibro-acoustic characterization of flexible hose in CO2 car air conditioning systems

    Science.gov (United States)

    Angelini, F.; Bergami, A.; Martarelli, M.; Tomasini, E. P.

    2008-06-01

    Following the EU directive 2006/40/EC proscribing from 2011 that refrigerant fluids must have a global warming potential not higher than 150, it will not be allowed anymore to employ the current R134a on car air conditioning systems. Maflow s.p.a (automotive hose maker) is developing products for each possible new refrigerant. This paper is focused on hoses for CO2 refrigerants operating in the worst conditions because of the high pressures and temperatures at which they are working (with R134a the high pressure is 18 bar and low pressure is 3 bar; with CO2 the high pressure is 100 bar and low pressure is 35 bar). Therefore the noise emission control of the CO2 air conditioning systems is very important. The aim of this study is to develop a standard measurement method for the vibro - acoustic characterization of High Pressure (HP - Shark F4) and Low Pressure (LP - ULEV) hoses to reduce noise emission and raise car passenger comfort; in particular deep research on high pressure hose. The method is based on the measurement of the vibration level of the hoses in a standard test bench by means of a Laser Doppler Vibrometer (LDV) and its acoustic emission by a sound intensity probe.

  13. Improved State Feedback H∞ Control for Flexible Air-Breathing Hypersonic Vehicles on LMI Approach

    Directory of Open Access Journals (Sweden)

    Zhang Xue

    2017-01-01

    Full Text Available Focusing on a nonlinear longitudinal dynamical model for Air-breathing Hypersonic Flight Vehicles (AHFV, a linearized model on a nominal trim condition is proposed. To stabilize the flight of an AHFV in the presence of external disturbances and actuator uncertainties, a state feedback H∞ control is designed. With bounds on the uncertainties, a feedback stabilization problem is converted to an optimal control problem and the cost function is minimized by solving a set of linear matrix inequalities. Since uncertainties in the design of AHFV are inevitable, to make a comparison, a general H∞ robust controller is constructed by only considering the disturbances firstly. Then the results are extended by incorporating the actual existing uncertainties as well as the external disturbances in the AHFV system. Numerical simulation shows that the controller, which takes both disturbances and uncertainties into account, can effectively stabilize the AHFV system.

  14. Performance of a prototype micro wind turbine in the manmade wind field from air conditioner of buildings

    Directory of Open Access Journals (Sweden)

    K. H. Goh

    2012-03-01

    Full Text Available Harnessing waste energy from the manmade air fields of buildings presents a new area of renewable energy to explore. Due to the unpredictability of the natural wind, this study is to evaluate the practicality for harnessing waste energy from the air conditioner exhaust units which are a more constant and predictable source available in the buildings. A prototype of the micro wind turbine has been designed to minimize the negative effect of the exhaust sources. After the micro wind turbine was manufactured, the performance of the turbine was tested in the selected air conditioner exhaust unit. Increasing the rotor solidity and decreasing the resistance of the generator contribute to improved starting torque and decreased generator break in torque respectively in the design. The power generation of the micro wind turbine increases with an increase of the rotor speed. The 24-hour operation of the prototype presents an observation for both exhaust performance and power generation prediction when the prototype is mounted on the exhaust unit.

  15. Morphometric changes of corneal endothelial cells following intracameral air for micro perforation of the Descemet Membrane during big-bubble deep anterior lamellar keratoplasty

    Directory of Open Access Journals (Sweden)

    Ashbala Khattak

    2016-04-01

    Conclusion: The presence of air inside the anterior chamber for a short term may not cause further endothelial cell loss and can be safely performed to prevent postoperative Descemet Membrane detachment in case of micro perforations.

  16. Autonomous Landing and Ingress of Micro-Air-Vehicles in Urban Environments Based on Monocular Vision

    Science.gov (United States)

    Brockers, Roland; Bouffard, Patrick; Ma, Jeremy; Matthies, Larry; Tomlin, Claire

    2011-01-01

    Unmanned micro air vehicles (MAVs) will play an important role in future reconnaissance and search and rescue applications. In order to conduct persistent surveillance and to conserve energy, MAVs need the ability to land, and they need the ability to enter (ingress) buildings and other structures to conduct reconnaissance. To be safe and practical under a wide range of environmental conditions, landing and ingress maneuvers must be autonomous, using real-time, onboard sensor feedback. To address these key behaviors, we present a novel method for vision-based autonomous MAV landing and ingress using a single camera for two urban scenarios: landing on an elevated surface, representative of a rooftop, and ingress through a rectangular opening, representative of a door or window. Real-world scenarios will not include special navigation markers, so we rely on tracking arbitrary scene features; however, we do currently exploit planarity of the scene. Our vision system uses a planar homography decomposition to detect navigation targets and to produce approach waypoints as inputs to the vehicle control algorithm. Scene perception, planning, and control run onboard in real-time; at present we obtain aircraft position knowledge from an external motion capture system, but we expect to replace this in the near future with a fully self-contained, onboard, vision-aided state estimation algorithm. We demonstrate autonomous vision-based landing and ingress target detection with two different quadrotor MAV platforms. To our knowledge, this is the first demonstration of onboard, vision-based autonomous landing and ingress algorithms that do not use special purpose scene markers to identify the destination.

  17. Flexible SiO2 cantilevers for torsional self-aligning micro scale four-point probes

    DEFF Research Database (Denmark)

    Kjær, Daniel; Gammelgaard, Lauge; Bøggild, Peter;

    2007-01-01

    to compensate for misalignment is improved at a cost of reduced spring constant. Analytical calculations, numerical simulations on cantilever deflection and comparison with experimental results indicate that a reasonable compromise between torsional flexibility and overall spring constant can be achieved...... by proper dimensioning and placement of the hinge. Furthermore, it is shown that polymeric macro scale cantilever models can provide a fast and reliable understanding of the mechanical deflection properties of microfabricated SiO2 cantilevers....

  18. Flexible high power-per-weight perovskite solar cells with chromium oxide-metal contacts for improved stability in air

    Science.gov (United States)

    Kaltenbrunner, Martin; Adam, Getachew; Głowacki, Eric Daniel; Drack, Michael; Schwödiauer, Reinhard; Leonat, Lucia; Apaydin, Dogukan Hazar; Groiss, Heiko; Scharber, Markus Clark; White, Matthew Schuette; Sariciftci, Niyazi Serdar; Bauer, Siegfried

    2015-10-01

    Photovoltaic technology requires light-absorbing materials that are highly efficient, lightweight, low cost and stable during operation. Organolead halide perovskites constitute a highly promising class of materials, but suffer limited stability under ambient conditions without heavy and costly encapsulation. Here, we report ultrathin (3 μm), highly flexible perovskite solar cells with stabilized 12% efficiency and a power-per-weight as high as 23 W g-1. To facilitate air-stable operation, we introduce a chromium oxide-chromium interlayer that effectively protects the metal top contacts from reactions with the perovskite. The use of a transparent polymer electrode treated with dimethylsulphoxide as the bottom layer allows the deposition--from solution at low temperature--of pinhole-free perovskite films at high yield on arbitrary substrates, including thin plastic foils. These ultra-lightweight solar cells are successfully used to power aviation models. Potential future applications include unmanned aerial vehicles--from airplanes to quadcopters and weather balloons--for environmental and industrial monitoring, rescue and emergency response, and tactical security applications.

  19. Non-fragile switching tracking control for a flexible air-breathing hypersonic vehicle based on polytopic LPV model

    Institute of Scientific and Technical Information of China (English)

    Huang Yiqing; Sun Changyin; Qian Chengshan; Wang Li

    2013-01-01

    This article proposes a linear parameter varying (LPV) switching tracking control scheme for a flexible air-breathing hypersonic vehicle (FAHV).First,a polytopic LPV model is constructed to represent the complex nonlinear longitudinal model of the FAHV by using Jacobian linearization and tensor-product (T-P) model transformation approach.Second,for less conservative controller design purpose,the flight envelope is divided into four sub-regions and a non-fragile LPV controller is designed for each parameter sub-region.These non-fragile LPV controllers are then switched in order to guarantee the closed-loop FAHV system to be asymptotically stable and satisfy a specified performance criterion.The desired non-fragile LPV switching controller is found by solving a convex constraint problem which can be efficiently solved using available linear matrix inequality (LMI) techniques,and robust stability analysis of the closed-loop FAHV system is verified based on multiple Lypapunov functions (MLFs).Finally,numerical simulations have demonstrated the effectiveness of the proposed approach.

  20. Fully self-contained vision-aided navigation and landing of a micro air vehicle independent from external sensor inputs

    Science.gov (United States)

    Brockers, Roland; Susca, Sara; Zhu, David; Matthies, Larry

    2012-06-01

    Direct-lift micro air vehicles have important applications in reconnaissance. In order to conduct persistent surveillance in urban environments, it is essential that these systems can perform autonomous landing maneuvers on elevated surfaces that provide high vantage points without the help of any external sensor and with a fully contained on-board software solution. In this paper, we present a micro air vehicle that uses vision feedback from a single down looking camera to navigate autonomously and detect an elevated landing platform as a surrogate for a roof top. Our method requires no special preparation (labels or markers) of the landing location. Rather, leveraging the planar character of urban structure, the landing platform detection system uses a planar homography decomposition to detect landing targets and produce approach waypoints for autonomous landing. The vehicle control algorithm uses a Kalman filter based approach for pose estimation to fuse visual SLAM (PTAM) position estimates with IMU data to correct for high latency SLAM inputs and to increase the position estimate update rate in order to improve control stability. Scale recovery is achieved using inputs from a sonar altimeter. In experimental runs, we demonstrate a real-time implementation running on-board a micro aerial vehicle that is fully self-contained and independent from any external sensor information. With this method, the vehicle is able to search autonomously for a landing location and perform precision landing maneuvers on the detected targets.

  1. Experimental Investigation of a Shrouded Rotor Micro Air Vehicle in Hover and in Edgewise Gusts

    Science.gov (United States)

    Hrishikeshavan, Vikram

    Due to the hover capability of rotary wing Micro Air Vehicles (MAVs), it is of interest to improve their aerodynamic performance, and hence hover endurance (or payload capability). In this research, a shrouded rotor configuration is studied and implemented, that has the potential to offer two key operational benefits: enhanced system thrust for a given input power, and improved structural rigidity and crashworthiness of an MAV platform. The main challenges involved in realising such a system for a lightweight craft are: design of a lightweight and stiff shroud, and increased sensitivity to external flow disturbances that can affect flight stability. These key aspects are addressed and studied in order to assess the capability of the shrouded rotor as a platform of choice for MAV applications. A fully functional shrouded rotor vehicle (disk loading 60 N/ m2) was designed and constructed with key shroud design variables derived from previous studies on micro shrouded rotors. The vehicle weighed about 280 g (244 mm rotor diameter). The shrouded rotor had a 30% increase in power loading in hover compared to an unshrouded rotor. Due to the stiff, lightweight shroud construction, a net payload benefit of 20-30 g was achieved. The different components such as the rotor, stabilizer bar, yaw control vanes and the shroud were systematically studied for system efficiency and overall aerodynamic improvements. Analysis of the data showed that the chosen shroud dimensions was close to optimum for a design payload of 250 g. Risk reduction prototypes were built to sequentially arrive at the final configuration. In order to prevent periodic oscillations in ight, a hingeless rotor was incorporated in the shroud. The vehicle was successfully ight tested in hover with a proportional-integralderivative feedback controller. A flybarless rotor was incorporated for efficiency and control moment improvements. Time domain system identification of the attitude dynamics of the flybar and

  2. A conceptual framework for designing micro-worlds for complex work domains: a case study of the Cabin Air Management System.

    Science.gov (United States)

    Sauer, J; Wastell, D G; Hockey, G R

    2000-01-01

    A conceptual framework for the design of micro-worlds is presented in this paper. This is illustrated by a micro-world, called Cabin Air Management System (CAMS), that has been used in a research program to investigate human behavior during work with complex systems. Although CAMS is based on the operational context of spaceflight, its underlying principles correspond to a process control task. The authors propose a theoretical framework for micro-world design, which was used to guide the development of the CAMS micro-world. This may provide a helpful guideline for researchers wishing to develop a micro-world by using a more structured approach. A detailed technical description of CAMS is given to demonstrate the kind of real-world scenarios that may be simulated with this task environment. Finally, general aspects of the utility of micro-world research are discussed.

  3. Numerical modeling of aerodynamics of airfoils of micro air vehicles in gusty environment

    Science.gov (United States)

    Gopalan, Harish

    The superior flight characteristics exhibited by birds and insects can be taken as a prototype of the most perfect form of flying machine ever created. The design of Micro Air Vehicles (MAV) which tries mimic the flight of birds and insects has generated a great deal of interest as the MAVs can be utilized for a number of commercial and military operations which is usually not easily accessible by manned motion. The size and speed of operation of a MAV results in low Reynolds number flight, way below the flying conditions of a conventional aircraft. The insensitivity to wind shear and gust is one of the required factors to be considered in the design of airfoil for MAVs. The stability of flight under wind shear is successfully accomplished in the flight of birds and insects, through the flapping motion of their wings. Numerous studies which attempt to model the flapping motion of the birds and insects have neglected the effect of wind gust on the stability of the motion. Also sudden change in flight conditions makes it important to have the ability to have an instantaneous change of the lift force without disturbing the stability of the MAV. In the current study, two dimensional rigid airfoil, undergoing flapping motion is studied numerically using a compressible Navier-Stokes solver discretized using high-order finite difference schemes. The high-order schemes in space and in time are needed to keep the numerical solution economic in terms of computer resources and to prevent vortices from smearing. The numerical grid required for the computations are generated using an inverse panel method for the streamfunction and potential function. This grid generating algorithm allows the creation of single-block orthogonal H-grids with ease of clustering anywhere in the domain and the easy resolution of boundary layers. The developed numerical algorithm has been validated successfully against benchmark problems in computational aeroacoustics (CAA), and unsteady viscous

  4. Dynamic of arm’s micro movements of elite athlete in Olympic exercises Rapid Fire Pistol and Air Pistol

    Directory of Open Access Journals (Sweden)

    Pyatkov V.T.

    2017-04-01

    Full Text Available Purpose: to scientifically substantiate the method of contactless determination of athlete hand’s movements in Olympic exercises with pistol. Material: in the research we used the data of 37 elite athletes in exercise Air Pistol (n=32 and in exercise Rapid Fire Pistol (n=5. Registration of pistol projection’s quickness of movement in target area was realized with the help of computer system Scatt. In total we analyzed 3100 space-time parameters of athletes’ technical-tactic actions in finalizing phase of shooting cycle. Results: we tested innovative method of contactless measuring of athlete’s hand’s micro movements in finalizing phase of shooting cycle. We found uncontrolled deviations from optimal pistol pointing position in vertical, horizontal and sagittal planes. Quickness of athlete hand’s movements in shooting process was determined. Conclusions: we scientifically substantiated the method of contactless determination of athlete hand’s movements at a distance in Olympic exercises with pistol. Besides, we determined the dynamic of athlete’s hand micro movements in Olympic exercises Rapid Fire Pistol та Air Pistol.

  5. Combustion of Gaseous Fuels with High Temperature Air in Normal- and Micro-gravity Conditions

    Science.gov (United States)

    Wang, Y.; Gupta, A. K.

    2001-01-01

    The objective of this study is determine the effect of air preheat temperature on flame characteristics in normal and microgravity conditions. We have obtained qualitative (global flame features) and some quantitative information on the features of flames using high temperature combustion air under normal gravity conditions with propane and methane as the fuels. This data will be compared with the data under microgravity conditions. The specific focus under normal gravity conditions has been on determining the global flame features as well as the spatial distribution of OH, CH, and C2 from flames using high temperature combustion air at different equivalence ratio.

  6. Laser patterning of highly conductive flexible circuits

    Science.gov (United States)

    Ji, Seok Young; Muhammed Ajmal, C.; Kim, Taehun; Chang, Won Seok; Baik, Seunghyun

    2017-04-01

    There has been considerable attention paid to highly conductive flexible adhesive (CFA) materials as electrodes and interconnectors for future flexible electronic devices. However, the patterning technology still needs to be developed to construct micro-scale electrodes and circuits. Here we developed the selective laser sintering technology where the pattering and curing were accomplished simultaneously without making additional masks. The CFA was composed of micro-scale Ag flakes, multiwalled carbon nanotubes decorated with Ag nanoparticles, and a nitrile-butadiene-rubber matrix. The Teflon-coated polyethylene terephthalate film was used as a flexible substrate. The width of lines (50-500 μm) and circuit patterns were controlled by the programmable scanning of a focused laser beam (power = 50 mW, scanning speed = 1 mm s-1). The laser irradiation removed solvent and induced effective coalescence among fillers providing a conductivity as high as 25 012 S cm-1. The conductivity stability was excellent under the ambient air and humid environments. The normalized resistance change of the pattern was smaller than 1.2 at the bending radius of 5 mm. The cyclability and adhesion of the laser-sintered line pattern on the substrate was excellent. A flexible circuit was fabricated sequentially for operating light emitting diodes during the bending motion, demonstrating excellent feasibility for practical applications in flexible electronics.

  7. In vitro evaluation of a micro-Doppler catheter for detection and aspiration of venous air emboli.

    Science.gov (United States)

    Bigeleisen, Paul E

    2007-11-01

    Venous air embolism (VAE) is a potentially fatal complication of surgery when open veins at a surgical site are exposed to ambient air pressure which exceeds the pressure in the venous system. Common techniques of detecting VAE are precordial Doppler monitoring and transesophogeal echocardiography. Precordial Doppler monitoring has poor accuracy and transesophogeal echocardiography is expensive and user-intensive. In both methods, a separate catheter must be inserted into the vena cava so that an embolus may be aspirated if it is detected. We created a micro-Doppler assembly using two ceramic transducers fitted over a 5.8F multiorifice central venous catheter. This micro-Doppler catheter (MDC) was tested in vitro using a static tank and an artificial vena cava (AVC). The MDC was also tested for acoustic pressure and current leakage in the static tank and for heat generation and cavitation in the AVC. The MDC was able to detect bubbles more than 2 mm in diameter with 100% accuracy. A blinded observer was able to identify the onset of vapor lock in 10 of 10 trials. The same observer was able to terminate vapor lock in 10 of 10 trials. The acoustic pressures measured were <1.8 MPa. There was no increase in temperature in the AVC over 24 h and there was no evidence of cavitation in the AVC over 4 h. We have created a MDC that can detect air emboli and relieve vapor lock in a simulated vena cava and atrium. This catheter could be placed percutaneously in the vena cava. Based on the measurements of acoustic pressure, temperature in the AVC and lack of cavitation in the AVC, the device appears to be safe for use in humans. More studies are required to determine if the catheter could be used to detect and aspirate VAE during surgeries where VAE is likely, such as sitting craniotomy.

  8. Rapid microRNA changes in airways of human volunteers after controlled exposure to air pollutants

    Science.gov (United States)

    Introduction/Rationale: Exposure to air pollutants, including ozone and diesel exhaust (DE) are known to cause acute cardiopulmonary dysfunction; however, the molecular mechanisms underlying these changes remain elusive. One mechanism for rapid regulation of multiple genes is a...

  9. Fatigue study and improve reliability of cantilever type micro piezoelectric energy harvesters reinforced with flexible adhesive conductive tape

    Science.gov (United States)

    Lin, T. K.; Hsieh, Y. C.; Chen, C. T.; Chen, J. J.; Wu, W. J.

    2016-04-01

    cracked after 13 million cycles under 0.5g and 1 million cycles under 0.6g. The PEH has significant output power decreasing after the electrode is cracked and before being fully open circuit. The cracks of stainless steel substrate was also found after 1 million cycles under 0.7g vibration. For the device reinforced with conductive adhesive tape, we can see a steady output without degradation extended to more than 1.5 million cycles under 0.7g vibration. The other interesting finding in this study is with the added damping after adhering the conductive tape, the frequency bandwidth increased from 1.5Hz to 4Hz under 0.5g vibration level while the resonance frequency increased from 105Hz to 128Hz. Moreover, the reinforced devices have much better stability and linearity performance compared with the original devices. All the experimental details and discussion of the flexible conductive adhesive tape reinforced PEH will all be detailed in this paper.

  10. Air annealing induced transformation of cubic CdSe microspheres into hexagonal nanorods and micro-pyramids

    Energy Technology Data Exchange (ETDEWEB)

    Kale, Rohidas B., E-mail: rb_kale@yahoo.co.in [Department of Physics, Institute of Science, Mumbai 400032, M.S. (India); Lu, Shih-Yuan, E-mail: sylu@mx.nthu.edu.tw [Department of Chemical Engineering, National Tsing-Hua University, Hsin-Chu 30013, Taiwan (China)

    2015-08-15

    Highlights: • Nanocrystalline CdSe thin films were deposited using inexpensive CBD method. • Air annealing induced structural and interesting morphological transformation. • The as-deposited CdSe thin films showed a blue shift in its optical spectra. • The films showed a red shift in their optical spectra after annealing. - Abstract: CdSe thin films have been deposited onto glass substrates using a chemical bath deposition method at relatively low temperatures (40 °C). The precursors used for the deposition of the thin films are cadmium nitrate hexahydrate, freshly prepared sodium selenosulfate solution and aqueous ammonia solution as a complex as well as pH adjusting reagent. In order to study the influence of air annealing on their physicochemical properties, the as-deposited CdSe thin films were further annealed at 200 °C and 400 °C for 3 h in air atmosphere. Significant changes in the morphology and photonic properties were clearly observed after the thermal annealing of the CdSe thin films. The as-deposited CdSe films grow with the cubic phase that transforms into mixed cubic and hexagonal wurtzite phase with improved crystalline quality of the films after the air annealing. Morphological observation reveals that the as-deposited thin films grow with multilayer that consists of network or mesh like structure, uniformly deposited on the glass substrate over which microspheres are uniformly distributed. After air annealing, CdSe nanorods emerged from the microspheres along with conversion of few microspheres into micro-pyramids. The UV–visible study illustrates that the as-deposited thin film shows blue shifts in its optical spectrum and the spectrum was red-shifted after annealing the CdSe thin films. The band gap of the CdSe thin films were found to be decreased after the thermal treatment.

  11. An interval-possibilistic basic-flexible programming method for air quality management of municipal energy system through introducing electric vehicles.

    Science.gov (United States)

    Yu, L; Li, Y P; Huang, G H; Shan, B G

    2017-09-01

    Contradictions of sustainable transportation development and environmental issues have been aggravated significantly and been one of the major concerns for energy systems planning and management. A heavy emphasis is placed on stimulation of electric vehicles (EVs) to handle these problems associated with various complexities and uncertainties in municipal energy system (MES). In this study, an interval-possibilistic basic-flexible programming (IPBFP) method is proposed for planning MES of Qingdao, where uncertainties expressed as interval-flexible variables and interval-possibilistic parameters can be effectively reflected. Support vector regression (SVR) is used for predicting electricity demand of the city under various scenarios. Solutions of EVs stimulation levels and satisfaction levels in association with flexible constraints and predetermined necessity degrees are analyzed, which can help identify the optimized energy-supply patterns that could plunk for improvement of air quality and hedge against violation of soft constraints. Results disclose that largely developing EVs can help facilitate the city's energy system with an environment-effective way. However, compared to the rapid growth of transportation, the EVs' contribution of improving the city's air quality is limited. It is desired that, to achieve an environmentally sustainable MES, more concerns should be focused on the integration of increasing renewable energy resources, stimulating EVs as well as improving energy transmission, transport and storage. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Rigid-body kinematics versus flapping kinematics of a flapping wing micro air vehicle

    OpenAIRE

    Caetano, J.V.; Weehuizen, M.B.; De Visser, C.C.; De Croon, G.C.H.E.; de Mulder, M.

    2015-01-01

    Several formulations have been proposed to model the dynamics of ornithopters, with inconclusive results regarding the need for complex kinematic formulations. Furthermore, the impact of assumptions made in the collected results was never assessed by comparing simulations with real flight data. In this study two dynamic models of a Flapping Wing Micro Aerial Vehicle (FWMAV) were derived and compared: a) single rigid body aircraft equations of motion and b) Virtual Work Principle derivation fo...

  13. Individual particle analysis of coarse air suspended particulate material by synchrotron radiation X-ray micro fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Silvana; Melo Junior, Ariston [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo. Dept. de Recursos Hidricos]. E-mail: silvana@fec.unicamp.br; Perez, Carlos Alberto [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil)]. E-mail: perez@lnls.br; Vives, Ana Elisa S. de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Nascimento Filho, Virgilio F. [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Instrumentacao Nuclear]. E-mail: virgilio@cena.usp.br

    2005-07-01

    The purpose of this work is evaluate the size of individual particles present in the air suspended particulate material collected in Campinas, Sao Paulo State, and analyze quantitatively the particles using the synchrotron radiation X-ray micro fluorescence ({mu}-SRXRF) associated with the fundamental parameter method to correct attenuation/absorption effects by the matrix. The particles analyzed have size between 50-10 {mu}m and to perform the spatial distribution a white beam of synchrotron radiation condensed by a conical capillary (13 {mu}m diameter) was used. For the quantitative analysis punctual measures in thin films standards in Mylar subtract were performed. The elements detected were Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ba and Pb. (author)

  14. Conceptual Design Tool to Analyze Electrochemically-Powered Micro Air Vehicles

    Science.gov (United States)

    2011-03-01

    battery chemistries include the lithium thionyl chloride battery (Li/SOCl2), the zinc-air... battery , and the lithium -ion polymer battery . Compared to other lithium anode batteries , a lithium thionyl chloride system has the highest energy...40Staniewicz, R.J., “ Lithium Thionyl Chloride Cells and Batteries Technical Predictions Versus 1994 Realities,” Journal of Power Sources, Vol. 54,

  15. Nano-mechanical properties and structural of a 3D-printed biodegradable biomimetic micro air vehicle wing

    Science.gov (United States)

    Salami, E.; Montazer, E.; Ward, T. A.; Ganesan, P. B.

    2017-06-01

    The biomimetic micro air vehicles (BMAV) are unmanned, micro-scaled aircraft that are bio-inspired from flying organisms to achieve the lift and thrust by flapping their wings. The main objectives of this study are to design a BMAV wing (inspired from the dragonfly) and analyse its nano-mechanical properties. In order to gain insights into the flight mechanics of dragonfly, reverse engineering methods were used to establish three-dimensional geometrical models of the dragonfly wings, so we can make a comparative analysis. Then mechanical test of the real dragonfly wings was performed to provide experimental parameter values for mechanical models in terms of nano-hardness and elastic modulus. The mechanical properties of wings were measured by nanoindentre. Finally, a simplified model was designed and the dragonfly-like wing frame structure was bio-mimicked and fabricated using a 3D printer. Then mechanical test of the BMAV wings was performed to analyse and compare the wings under a variety of simplified load regimes that are concentrated force, uniform line-load and a torque. This work opened up the possibility towards developing an engineering basis for the biomimetic design of BMAV wings.

  16. Experimental analysis of artificial dragonfly wings using black graphite and fiberglass for use in Biomimetic Micro Air Vehicles (BMAVs

    Directory of Open Access Journals (Sweden)

    Nair Praveena

    2015-01-01

    Full Text Available This article examines the suitability of two different materials which are black graphite carbon fiber and red pre-impregnated fiberglass from which to fabricate artificial dragonfly wing frames. These wings could be of use in Biomimetic Micro Aerial Vehicles (BMAV. BMAV are a new class of unmanned micro-sized air vehicles that mimic flying biological organisms. Insects, such as dragonflies, possess corrugated and complex vein structures that are difficult to mimic. Simplified dragonfly wing frames were fabricated from these materials and then a nano-composite film was adhered to them, which mimics the membrane of an actual dragonfly. Experimental analysis of these results showed that although black graphite carbon fiber and red pre-impregnated fiberglass offer some structural advantages, red pre-impregnated fiberglass was a less preferred option due to its warpage and shrinking effects. Black graphite carbon fiber with its high load bearing capability is a more suitable choice for consideration in future BMAV applications.

  17. Energy-Based Design of Reconfigurable Micro Air Vehicle (MAV) Flight Structures

    Science.gov (United States)

    2014-02-01

    wingspan, taper ratio, and sweep angle are free to vary independently of each other. Clearly, a wing capable of telescoping , chord extension, and...that can substantially change shape to adapt to changing mission environments. Morphing wings with planform capabilities of telescoping , chord...This report was cleared for public release by the USAF 88th Air Base Wing (88 ABW) Public Affairs Office (PAO) and is available to the general

  18. "Everything Is Kind of up in the Air": Flexible and Creative Organizing at an Arts-Based Nonprofit

    Science.gov (United States)

    Scarduzio, Jennifer A.

    2009-01-01

    This study expands upon the research of arts-based inquiry by exploring the ways creativity and flexibility impact communicating and organizing in an arts-based nonprofit. Based on ethnographic observation and interviews, this piece reveals specific tensions that impact the ways staff members and mentors communicate: (a) consistency/inconsistency,…

  19. EFFECTS OF SIMPLIFIED CHEMICAL KINETIC MODEL ON THE MICRO-FLAME STRUCTURE AND TEMPERATURE OF THE LEAN PREMIXED METHANE-AIR MIXTURES

    Directory of Open Access Journals (Sweden)

    JUNJIE CHEN

    2015-07-01

    Full Text Available The effect of simplified chemical kinetic model on the micro-flame structure, central axis and wall temperatures were investigated with different one-step global chemical kinetic mechanisms following Mantel, Duterque and Fernández-Tarrazo models. Numerical investigations of the premixed methane-air flame in the micro-channel and lean conditions were carried out to compare and analyze the effect of the comprehensive chemical kinetic mechanisms. The results indicate that one-step global chemical kinetic mechanism affects both the micro-flame shape and the combustion temperature. Among three simulation models, Mantel model allows a stable micro-flame with a bamboo shoot form, which anchor at the inlet. Duterque model gives a stable elongated micro-flame with a considerable ignition delay, and a dead zone with fluid accumulation is observed at the entrance, which may explain the very high combustion temperature and the fast reaction rate obtained, despite the micro-flame development presents a very hot spot and causes a broadening of the combustion zone. Fernández-Tarrazo model results in a rapid extinction and doesn't seem to take all the kinetic behavior into account for the appropriate micro-combustion simulations.

  20. Hydrostatic pressure effect on micro air bubbles deposited on surfaces with a retreating tip.

    Science.gov (United States)

    Huynh, So Hung; Wang, Jingming; Yu, Yang; Ng, Tuck Wah

    2014-06-01

    The effect of hydrostatic pressure on 6 μL air bubbles formed on micropillar structured PDMS and silicone surfaces using a 2 mm diameter stainless steel tip retreated at 1 mm/s was investigated. Dimensional analysis of the tip retraction process showed the experiments to be conducted in the condition where fluid inertial forces are comparable in magnitude with surface tension forces, while viscous forces were lower. Larger bubbles could be left behind on the structured PDMS surface. For hydrostatic pressures in excess of 20 mm H2O (196 Pa), the volume of bubble deposited was found to decrease progressively with pressure increase. The differences in width of the deposited bubbles (in contact with the substrate) were significant at any particular pressure but marginal in height. The attainable height before rupture reduced with pressure increase, thereby accounting for the reducing dispensed volume characteristic. On structured PDMS, the gaseous bridge width (in contact with the substrate) was invariant with tip retraction, while on silicone it was initially reducing before becoming invariant in the lead up to rupture. With silicone, hence, reductions in the contact width and height were both responsible for reduced volumes with pressure increase. Increased hydrostatic pressure was also found to restrict the growth in contact width on silicone during the stage when air was injected in through the tip. The ability to effect bubble size in such a simple manner may already be harnessed in nature and suggests possibilities in technological applications.

  1. In Situ Coupling of Strung Co4N and Intertwined N-C Fibers toward Free-Standing Bifunctional Cathode for Robust, Efficient, and Flexible Zn-Air Batteries.

    Science.gov (United States)

    Meng, Fanlu; Zhong, Haixia; Bao, Di; Yan, Junmin; Zhang, Xinbo

    2016-08-17

    Flexible power sources with high energy density are crucial for the realization of next-generation flexible electronics. Theoretically, rechargeable flexible zinc-air (Zn-air) batteries could provide high specific energy, while their large-scale applications are still greatly hindered by high cost and resources scarcity of noble-metal-based oxygen evolution reaction (OER)/oxygen reduction reaction (ORR) electrocatalysts as well as inferior mechanical properties of the air cathode. Combining metallic Co4N with superior OER activity and Co-N-C with perfect ORR activity on a free-standing and flexible electrode could be a good step for flexible Zn-air batteries, while lots of difficulties need to be overcome. Herein, as a proof-of-concept experiment, we first propose a strategy for in situ coupling of strung Co4N and intertwined N-C fibers, by pyrolyzation of the novel pearl-like ZIF-67/polypyrrole nanofibers network rooted on carbon cloth. Originating from the synergistic effect of Co4N and Co-N-C and the stable 3D interconnected conductive network structure, the obtained free-standing and highly flexible bifunctional oxygen electrode exhibits excellent electrocatalytic activity and stability for both OER and ORR in terms of low overpotential (310 mV at 10 mA cm(-2)) for OER, a positive half-wave potential (0.8 V) for ORR, and a stable current density retention for at least 20 h, and especially, the obtained Zn-air batteries exhibit a low discharge-charge voltage gap (1.09 V at 50 mA cm(-2)) and long cycle life (up to 408 cycles). Furthermore, the perfect bendable and twistable and rechargeable properties of the flexible Zn-air battery particularly make it a potentially power portable and wearable electronic device.

  2. Development of a fuel flexible, air-regulated, modular, and electrically integrated SOFC-system (FlameSOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Voss, S.; Trimis, D. [TU Bergakademie Freiberg (Germany). Inst. of Thermal Engineering; Valldorf, J. [VDI/VDE Innovation + Technik GmbH (Germany)

    2010-07-01

    The present paper summarizes experimental results from the operation of the SOFC based micro-CHP unit developed within the framework of the project FlameSOFC. The project is co-financed by the European Commission as an Integrated Project within the 6{sup th} framework program. The objective is the development of an innovative SOFC-based micro-CHP system capable of operating with different gaseous and liquid fuels and fulfilling the technological and market requirements at a European level. The partners involved in the FlameSOFC project bring together a sufficient number of important European actors on the scientific, research and industry level including SMEs and industrial partners from the heating sector. The presented work concerns the operation of the 2{sup nd} phase prototype FlameSOFC system, with a 1 kW{sub el.} SOFC stack and natural gas as feedstock. (orig.)

  3. Design and development of an unconventional VTOL micro air vehicle: The Cyclocopter

    Science.gov (United States)

    Benedict, Moble; Chopra, Inderjit

    2012-06-01

    This paper discusses the systematic experimental and vehicle design/development studies conducted at the University of Maryland which culminated in the development of the first flying Cyclocopter in the history. Cyclocopter is a novel Vertical Take-Off and Landing (VTOL) aircraft, which utilizes cycloidalrotors (cyclorotors), a revolutionary horizontal axis propulsion concept, that has many advantages such as higher aerodynamic efficiency, maneuverability and high-speed forward flight capability when compared to a conventional helicopter rotor. The experimental studies included a detailed parametric study to understand the effect of rotor geometry and blade kinematics on cyclorotor hover performance. Based on the experimental results, higher blade pitch angles were found to improve thrust and increase the power loading (thrust per unit power) of the cyclorotor. Asymmetric pitching with higher pitch angle at the top than at the bottom produced better power loading. The chordwise optimum pitching axis location was observed to be around 25-35% of the blade chord. Because of the flow curvature effects, the cycloidal rotor performance was a strong function of the chord/radius ratio. The optimum chord/radius ratios were extremely high, around 0.5-0.8, depending on the blade pitching amplitude. A flow field investigation was also conducted using Particle Image Velocimetry (PIV) to unravel the physics behind thrust production of a cyclorotor. PIV studies indicated evidence of a stall delay as well as possible increases in lift on the blades from the presence of a leading edge vortex. The goal of all these studies was to understand and optimize the performance of a micro-scale cyclorotor so that it could be used in a flying vehicle. An optimized cyclorotor was used to develop a 200 gram cyclocopter capable of autonomous stable hover using an onboard feedback controller.

  4. Novel design of a compacted micro-structured air-breathing PEM fuel cell as a power source for mobile phones

    Directory of Open Access Journals (Sweden)

    Maher A.R. Sadiq Al-Baghdadi

    2010-07-01

    Full Text Available The presence of microelectromechanical system (MEMS technology makes it possible to manufacture the miniaturized fuel cell systems for application in portable electronic devices. The majority of research on micro-scale fuel cells is aimed at micro-power applications. There are many new miniaturized applications which can only be realized if a higher energy density power source is available compared to button cells and other small batteries. In small-scale applications, the fuel cell should be exceptionally small and have highest energy density. One way to achieve these requirements is to reduce the thickness of the cell (compacted-design for increasing the volumetric power density of a fuel cell power supply. A novel, simple to construct, air-breathing micro-structured PEM fuel cell which work in still or slowly moving air has been developed. The novel geometry enables optimum air access to the cathode without the need for pumps, fans or similar devices. In addition, the new design can achieve much higher active area to volume ratios, and hence higher volumetric power densities. Three-dimensional, multi-phase, non-isothermal CFD model of this novel design has been developed. This comprehensive model account for the major transport phenomena in an air-breathing micro-structured PEM fuel cell: convective and diffusive heat and mass transfer, electrode kinetics, transport and phase-change mechanism of water, and potential fields. The model is shown to understand the many interacting, complex electrochemical, and transport phenomena that cannot be studied experimentally. Fully three-dimensional results of the species profiles, temperature distribution, potential distribution, and local current density distribution are presented and analyzed with a focus on the physical insight and fundamental understanding. They can provide a solid basis for optimizing the geometry of the PEM micro fuel cell stack running with a passive mode.

  5. Treatment of micro air bubbles in rat adipose tissue at 25 kPa altitude exposures with perfluorocarbon emulsions and nitric oxide

    DEFF Research Database (Denmark)

    Randsøe, Thomas; Hyldegaard, O

    2014-01-01

    . The effect is ascribed to an increased solubility and transport capacity of respiratory gases in the PFC emulsion and possibly enhanced nitrogen washout through NO-increased blood flow rate and/or the removal of endothelial micro bubble nuclei precursors. Previous reports have shown that metabolic gases (i...... of nitrogen, or in contrast (2) promote bubble growth and stabilization through an increased oxygen supply. METHODS: In anesthetized rats, micro air bubbles (containing 79% nitrogen) of 4-500 nl were injected into exposed abdominal adipose tissue. Rats were decompressed in 36 min to 25 kPa (~10,376 m above...

  6. Análisis exergético de un sistema flexible de aire acondicionado don deshidratación

    OpenAIRE

    Guallar Paracuellos, Jesús; De Gracia Villanueva, Mª Dolores

    2005-01-01

    Frente a la configuración típica de los sistemas de aire acondicionado de ciclo abierto que emplean deshidratación, en los que el caudal de retorno está fuertemente ligado al caudal de proceso, se propone un nuevo esquema que mejora la flexibilidad de la instalación, al desacoplar ambos caudales. Se propone esta solución para resolver un problema de aire acondicionado, apareciendo como equipo singular una rueda de deshidratación cuyo material adsorbente es silica gel. El procedimi...

  7. Pinatubo Global- to Micro-Scale Evolution: A Unified Picture from Space, Air, and Ground Measurements

    Science.gov (United States)

    Russell, Philip B.; Livingston, J. M.; Puesche, R. F.; Pollack, J. B.; Brooks, S.; Hamill, P.; Hughes, J.; Thomason, L.; Stowe, L.; Deshler, T.; Podolske, James R. (Technical Monitor)

    1995-01-01

    We combine space, air, and ground measurements to develop a composite picture of the post-Pinatubo aerosol, and assess the consistency and uncertainties of various measurement and retrieval techniques. impactor and optical counter measurements, as well as retrievals from optical depth spectra, paint a generally consistent picture of the evolution of particle effective radii, R(sub eff). In the first month after the eruption, although particle numbers increased by orders of magnitude, R(sub eff) was similar to the preeruption value of 4.2 micrometers, because both small (r less than 0.25 micrometers) and large (r greater than 0.6 micrometers) particles increased in number, Over the next 3-6 months, R(sub eff) increased rapidly to about 0.5 micrometers. In general, R(sub eff) continued to increase for about a year after the eruption. The peak wavelength of optical depth spectra increased from initial values of less than 0.42 micrometers to values between 0.78 and 1 micrometer. This coupled evolution in particle size distribution and optical depth spectra helps explain the relationship between the global maps of 0.5 and 1.0-micrometer optical depth derived from the AVHRR and SAGE satellite measurements. It also sets a context for evaluating remaining uncertainties in each of these satellite data products. We also make consensus recommendations for particle composition, shape, and temperature- and wavelength-dependent refractive index, and show how the latter effect on backscatter spectra can influence particle sizes retrieved from multiwavelength lidar measurements.

  8. 连接管在空调器降成本机型中的灵活运用%Flexible application of connecting pipe into the cost reduction machine type of air conditioner

    Institute of Scientific and Technical Information of China (English)

    冼志健; 梁勤奋

    2012-01-01

    在原有空调器配置不变的前提下,空调器连接管的灵活搭配应用,不但可以改善空调器制冷效果,而且能够降低空调器整机成本,提高其市场竞争力.%Under the original air conditioner configuration unchanged, the application of flexible collocation into air conditioner's connecting pipe,not only can improve the refrigeration effect of air conditioner,but also can reduce the cost of air conditioner and improve their market competitiveness.

  9. Optical and electrical characteristics of a single surface DBD micro-discharge produced in atmospheric-pressure nitrogen and synthetic air

    Science.gov (United States)

    Šimek, M.; Prukner, V.; Schmidt, J.

    2011-05-01

    Basic opto-electrical characteristics of a single micro-discharge generated in a surface DBD reactor with a coplanar electrode arrangement were studied with nanosecond time resolution. The discharge electrode geometry based on machinable glass-ceramic was optimized in order to get a system free of the circulating dielectric liquids that are frequently used to insulate and cool metallic electrodes. The build-up and decay of UV-vis-NIR emission by a single micro-discharge unaffected by concurrent or preceding discharge events was inspected during the first 10 µs of the micro-discharge evolution in nitrogen and in synthetic air. Obtained emission waveforms show a great similarity between the surface and volume streamers. The streamer volume-averaged N2(A) concentrations of ~8 × 1014 cm-3 were estimated at t = 1 µs decay time and concentrations of ~(2-4) × 1015 cm-3 were estimated during the streamer propagation phase in nitrogen.

  10. SU-E-I-84: Accuracy Comparison of Multi-Modality Image-Based Volumes of Rodent Solid Tumors Using In-Air Micro-CT Image Volume

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y [University of Kansas Hospital, Kansas City, KS (United States); Fullerton, G; Goins, B [University of Texas Health Science Center at San Antonio, San Antonio, TX (United States)

    2015-06-15

    Purpose: Tumor volume is considered as a better predictor for therapy response monitoring and tumor staging over Response Evaluation Criteria In Solid Tumors (RECIST) or World Health Organization (WHO) criteria. In this study, the accuracy of subcutaneous rodent tumor volumes using preclinical magnetic resonance imaging (MRI), micro-computed tomography (micro-CT) and ultrasound (US) equipment and with an external caliper was compared using in-air micro-CT image volume of excised tumors determined as reference tumor volume in our prior study. Methods: MR, US and micro-CT images of subcutaneous SCC4 head and neck tumor xenografts were acquired 4, 6, 9, 11 and 13 days after tumor cell inoculation. Before MR and US scans, caliper measurements were made. After tumors were excised, in-air micro-CT imaging and ex vivo caliper measurements were performed. Tumor volumes were calculated using formula V = (π/6)*a*b*c where a, b and c are the maximum diameters in three perpendicular dimensions determined by the three image modalities and caliper, and compared with reference tumor volume by linear regression analysis as well as Bland-Altman plots. A one-way Analysis of Variance (ANOVA) test was also performed to compare volumes among caliper measurements. Results: The correlation coefficients (R2) of the regression lines for tumor volumes measured by the three imaging modalities and caliper were 0.9939, 0.9669, 0.9806, 0.9274, 0.9619 and 0.9819 for MRI, US and micro-CT, caliperbeforeMRI, caliperbeforeUS and ex vivo caliper respectively. In Bland-Altman plots, the average of tumor volume difference from reference tumor volume (bias) was significant for caliper and micro- CT, but not for MRI and US. Comparison of caliper measurements showed a significant difference (p < 0.05). Conclusion: Using the in-air micro-CT image volume, tumor volume measured by MRI was the most accurate among the three imaging modalities. In vivo caliper volume measurements showed unreliability while ex

  11. GPS-based microenvironment tracker (MicroTrac) model to estimate time–location of individuals for air pollution exposure assessments: Model evaluation in central North Carolina

    Science.gov (United States)

    Breen, Michael S.; Long, Thomas C.; Schultz, Bradley D.; Crooks, James; Breen, Miyuki; Langstaff, John E.; Isaacs, Kristin K.; Tan, Yu-Mei; Williams, Ronald W.; Cao, Ye; Geller, Andrew M.; Devlin, Robert B.; Batterman, Stuart A.; Buckley, Timothy J.

    2014-01-01

    A critical aspect of air pollution exposure assessment is the estimation of the time spent by individuals in various microenvironments (ME). Accounting for the time spent in different ME with different pollutant concentrations can reduce exposure misclassifications, while failure to do so can add uncertainty and bias to risk estimates. In this study, a classification model, called MicroTrac, was developed to estimate time of day and duration spent in eight ME (indoors and outdoors at home, work, school; inside vehicles; other locations) from global positioning system (GPS) data and geocoded building boundaries. Based on a panel study, MicroTrac estimates were compared with 24-h diary data from nine participants, with corresponding GPS data and building boundaries of home, school, and work. MicroTrac correctly classified the ME for 99.5% of the daily time spent by the participants. The capability of MicroTrac could help to reduce the time–location uncertainty in air pollution exposure models and exposure metrics for individuals in health studies. PMID:24619294

  12. Successful Production of Piglets Derived from Expanded Blastocysts Vitrified Using a Micro Volume Air Cooling Method without Direct Exposure to Liquid Nitrogen

    OpenAIRE

    MISUMI, Koji; Hirayama, Yuri; EGAWA, Sachiko; Yamashita, Shoko; HOSHI, Hiroyoshi; Imai, Kei

    2013-01-01

    Abstract This study was conducted to clarify the feasibility of newly developed vitrification techniques for porcine embryos using the micro volume air cooling (MVAC) method without direct contact with liquid nitrogen (LN2). Expanded blastocysts were vitrified in a solution containing 6 M ethylene glycol, 0.6 M trehalose and 2% (wt/vol) polyethylene glycol in 10% HEPES-buffered PZM-5. The blastocysts were collected from gilts and vitrified using the new device (MVAC) or a Cryotop (CT). Blasto...

  13. Flexible Flatfoot

    Science.gov (United States)

    ... this page. Please enable Javascript in your browser. Flexible Flatfoot What Is Flatfoot? Flatfoot is often a ... may develop as a result of a flatfoot. Flexible Flatfoot Flexible flatfoot is one of the most ...

  14. Analytical performances of laser-induced micro-plasma of Al samples with single and double ultrashort pulses in air and with Ar-jet: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Semerok, A., E-mail: alexandre.semerok@cea.fr [CEA Saclay, DEN/DPC/SEARS/LISL, 91191 Gif-sur-Yvette (France); Dutouquet, C. [CEA Saclay, DEN/DPC/SEARS/LISL, 91191 Gif-sur-Yvette (France); INERIS/DRC/CARA/NOVA, F-60550 Verneuil En Halatte (France)

    2014-09-01

    Ultrashort pulse laser microablation coupled with optical emission spectroscopy was under study to obtain several micro-LIBS analytical features (shot-to-shot reproducibility, spectral line intensity and lifetime, calibration curves, detection limits). Laser microablation of Al matrix samples with known Cu- and Mg-concentrations was performed by single and double pulses of 50 fs and 1 ps pulse duration in air and with Ar-jet. The micro-LIBS analytical features obtained under different experimental conditions were characterized and compared. The highest shot-to-shot reproducibility and gain in plasma spectral line intensity were obtained with double pulses with Ar-jet for both 50 fs and 1 ps pulse durations. The best calibration curves were obtained with 1 ps pulse duration with Ar-jet. Micro-LIBS with ultrashort double pulses may find its effective application for surface elemental microcartography. - Highlights: • Analytical performances of micro-LIBS with ultrashort double pulses were studied. • The maximal line intensity gain of 20 was obtained with double pulses and Ar-jet. • LIBS gain was obtained without additional ablation of a sample by the second pulse. • LIBS properties were almost the same for both 50 fs and 1 ps pulses. • The micro-LIBS detection limit was around 35 ppm.

  15. Hydrophobically-associating cationic polymers as micro-bubble surface modifiers in dissolved air flotation for cyanobacteria cell separation.

    Science.gov (United States)

    Yap, R K L; Whittaker, M; Diao, M; Stuetz, R M; Jefferson, B; Bulmus, V; Peirson, W L; Nguyen, A V; Henderson, R K

    2014-09-15

    Dissolved air flotation (DAF), an effective treatment method for clarifying algae/cyanobacteria-laden water, is highly dependent on coagulation-flocculation. Treatment of algae can be problematic due to unpredictable coagulant demand during blooms. To eliminate the need for coagulation-flocculation, the use of commercial polymers or surfactants to alter bubble charge in DAF has shown potential, termed the PosiDAF process. When using surfactants, poor removal was obtained but good bubble adherence was observed. Conversely, when using polymers, effective cell removal was obtained, attributed to polymer bridging, but polymers did not adhere well to the bubble surface, resulting in a cationic clarified effluent that was indicative of high polymer concentrations. In order to combine the attributes of both polymers (bridging ability) and surfactants (hydrophobicity), in this study, a commercially-available cationic polymer, poly(dimethylaminoethyl methacrylate) (polyDMAEMA), was functionalised with hydrophobic pendant groups of various carbon chain lengths to improve adherence of polymer to a bubble surface. Its performance in PosiDAF was contrasted against commercially-available poly(diallyl dimethyl ammonium chloride) (polyDADMAC). All synthesised polymers used for bubble surface modification were found to produce positively charged bubbles. When applying these cationic micro-bubbles in PosiDAF, in the absence of coagulation-flocculation, cell removals in excess of 90% were obtained, reaching a maximum of 99% cell removal and thus demonstrating process viability. Of the synthesised polymers, the polymer containing the largest hydrophobic functionality resulted in highly anionic treated effluent, suggesting stronger adherence of polymers to bubble surfaces and reduced residual polymer concentrations.

  16. 微型旋翼无人机的磁操纵研究%Magnetic Operation of Rotor Micro Air Vehicle

    Institute of Scientific and Technical Information of China (English)

    富立; 王浩明; 杨丹迪

    2012-01-01

    磁操纵是微型无人机领域的一种新型控制方式,通过外界磁场的改变控制无人机的稳定。本文设计了一种磁动力控制微型旋翼飞行器,采用方形Helmholtz线圈产生匀强磁场来控制该飞行器的稳定,采用方形Maxwell线圈产生均匀梯度的磁场来控制飞行器的运动。在此基础上设计了框架式的磁场生成系统,该飞行器在框架之中飞行。经过理论计算及仿真,设计的磁场生成系统可以产生满足要求的磁场控制该飞行器使其稳定,进而沿水平方向运动。%Magnetic operation is a new kind of control method of micro air vehicle(MAV),which is to control its stability by changing the external magnetic field.In this thesis,we designed a new magnetic-controlling single rotor-wing MAV.We intended to use two square-Helmholtz coils to control the attitude of MAV by generating uniform magnetic field while two square-Maxwell coils to control the moving by generating magnetic gradient field.All the square coils are mountable on a cubic frame that has an opening to accommodate the MAV.In theory,the attitude of MAV can be controlled and the MAV can move horizontally through simulation.

  17. High-Frequency Fiber-Optic Ultrasonic Sensor Using Air Micro-Bubble for Imaging of Seismic Physical Models

    Directory of Open Access Journals (Sweden)

    Tingting Gang

    2016-12-01

    Full Text Available A micro-fiber-optic Fabry-Perot interferometer (FPI is proposed and demonstrated experimentally for ultrasonic imaging of seismic physical models. The device consists of a micro-bubble followed by the end of a single-mode fiber (SMF. The micro-structure is formed by the discharging operation on a short segment of hollow-core fiber (HCF that is spliced to the SMF. This micro FPI is sensitive to ultrasonic waves (UWs, especially to the high-frequency (up to 10 MHz UW, thanks to its ultra-thin cavity wall and micro-diameter. A side-band filter technology is employed for the UW interrogation, and then the high signal-to-noise ratio (SNR UW signal is achieved. Eventually the sensor is used for lateral imaging of the physical model by scanning UW detection and two-dimensional signal reconstruction.

  18. Flexible supercapacitors

    Institute of Scientific and Technical Information of China (English)

    Shan Shi; Chengjun Xu; Cheng Yang; Jia Li; Hongda Du; Baohua Li; Feiyu Kang

    2013-01-01

    Flexible supercapacitors show a great potential for applications in wearable,miniaturized,portable,largescale transparent and flexible consumer electronics due to their significant,inherent advantages,such as being flexible,lightweight,low cost and environmentally friendly in comparison with the current energy storage devices.In this report,recent progress on flexible supercapacitors,flexible electrodes and electrolytes is reviewed.In addition,the future challenges and opportunities are discussed.

  19. In-Situ Measurement of High-Temperature Proton Exchange Membrane Fuel Cell Stack Using Flexible Five-in-One Micro-Sensor.

    Science.gov (United States)

    Lee, Chi-Yuan; Weng, Fang-Bor; Kuo, Yzu-Wei; Tsai, Chao-Hsuan; Cheng, Yen-Ting; Cheng, Chih-Kai; Lin, Jyun-Ting

    2016-10-18

    In the chemical reaction that proceeds in a high-temperature proton exchange membrane fuel cell stack (HT-PEMFC stack), the internal local temperature, voltage, pressure, flow and current nonuniformity may cause poor membrane material durability and nonuniform fuel distribution, thus influencing the performance and lifetime of the fuel cell stack. In this paper micro-electro-mechanical systems (MEMS) are utilized to develop a high-temperature electrochemical environment-resistant five-in-one micro-sensor embedded in the cathode channel plate of an HT-PEMFC stack, and materials and process parameters are appropriately selected to protect the micro-sensor against failure or destruction during long-term operation. In-situ measurement of the local temperature, voltage, pressure, flow and current distributions in the HT-PEMFC stack is carried out. This integrated micro-sensor has five functions, and is favorably characterized by small size, good acid resistance and temperature resistance, quick response, real-time measurement, and the goal is being able to be put in any place for measurement without affecting the performance of the battery.

  20. In-Situ Measurement of High-Temperature Proton Exchange Membrane Fuel Cell Stack Using Flexible Five-in-One Micro-Sensor

    Directory of Open Access Journals (Sweden)

    Chi-Yuan Lee

    2016-10-01

    Full Text Available In the chemical reaction that proceeds in a high-temperature proton exchange membrane fuel cell stack (HT-PEMFC stack, the internal local temperature, voltage, pressure, flow and current nonuniformity may cause poor membrane material durability and nonuniform fuel distribution, thus influencing the performance and lifetime of the fuel cell stack. In this paper micro-electro-mechanical systems (MEMS are utilized to develop a high-temperature electrochemical environment-resistant five-in-one micro-sensor embedded in the cathode channel plate of an HT-PEMFC stack, and materials and process parameters are appropriately selected to protect the micro-sensor against failure or destruction during long-term operation. In-situ measurement of the local temperature, voltage, pressure, flow and current distributions in the HT-PEMFC stack is carried out. This integrated micro-sensor has five functions, and is favorably characterized by small size, good acid resistance and temperature resistance, quick response, real-time measurement, and the goal is being able to be put in any place for measurement without affecting the performance of the battery.

  1. High-Throughput Sequencing Identifies MicroRNAs from Posterior Intestine of Loach (Misgurnus anguillicaudatus) and Their Response to Intestinal Air-Breathing Inhibition.

    Science.gov (United States)

    Huang, Songqian; Cao, Xiaojuan; Tian, Xianchang; Wang, Weimin

    2016-01-01

    MicroRNAs (miRNAs) exert important roles in animal growth, immunity, and development, and regulate gene expression at the post-transcriptional level. Knowledges about the diversities of miRNAs and their roles in accessory air-breathing organs (ABOs) of fish remain unknown. In this work, we used high-throughput sequencing to identify known and novel miRNAs from the posterior intestine, an important ABO, in loach (Misgurnus anguillicaudatus) under normal and intestinal air-breathing inhibited conditions. A total of 204 known and 84 novel miRNAs were identified, while 47 miRNAs were differentially expressed between the two small RNA libraries (i.e. between the normal and intestinal air-breathing inhibited group). Potential miRNA target genes were predicted by combining our transcriptome data of the posterior intestine of the loach under the same conditions, and then annotated using COG, GO, KEGG, Swissprot and Nr databases. The regulatory networks of miRNAs and their target genes were analyzed. The abundances of nine known miRNAs were validated by qRT-PCR. The relative expression profiles of six known miRNAs and their eight corresponding target genes, and two novel potential miRNAs were also detected. Histological characteristics of the posterior intestines in both normal and air-breathing inhibited group were further analyzed. This study contributes to our understanding on the functions and molecular regulatory mechanisms of miRNAs in accessory air-breathing organs of fish.

  2. Modeling multi-scale aerosol dynamics and micro-environmental air quality near a large highway intersection using the CTAG model.

    Science.gov (United States)

    Wang, Yan Jason; Nguyen, Monica T; Steffens, Jonathan T; Tong, Zheming; Wang, Yungang; Hopke, Philip K; Zhang, K Max

    2013-01-15

    A new methodology, referred to as the multi-scale structure, integrates "tailpipe-to-road" (i.e., on-road domain) and "road-to-ambient" (i.e., near-road domain) simulations to elucidate the environmental impacts of particulate emissions from traffic sources. The multi-scale structure is implemented in the CTAG model to 1) generate process-based on-road emission rates of ultrafine particles (UFPs) by explicitly simulating the effects of exhaust properties, traffic conditions, and meteorological conditions and 2) to characterize the impacts of traffic-related emissions on micro-environmental air quality near a highway intersection in Rochester, NY. The performance of CTAG, evaluated against with the field measurements, shows adequate agreement in capturing the dispersion of carbon monoxide (CO) and the number concentrations of UFPs in the near road micro-environment. As a proof-of-concept case study, we also apply CTAG to separate the relative impacts of the shutdown of a large coal-fired power plant (CFPP) and the adoption of the ultra-low-sulfur diesel (ULSD) on UFP concentrations in the intersection micro-environment. Although CTAG is still computationally expensive compared to the widely-used parameterized dispersion models, it has the potential to advance our capability to predict the impacts of UFP emissions and spatial/temporal variations of air pollutants in complex environments. Furthermore, for the on-road simulations, CTAG can serve as a process-based emission model; Combining the on-road and near-road simulations, CTAG becomes a "plume-in-grid" model for mobile emissions. The processed emission profiles can potentially improve regional air quality and climate predictions accordingly.

  3. An Improved Evolvable Oscillator and Basis Function Set for Control of an Insect-Scale Flapping-Wing Micro Air Vehicle

    Institute of Scientific and Technical Information of China (English)

    John C.Gallagher; Michael W.Oppenheimer

    2012-01-01

    This paper introduces an improved evolvable and adaptive hardware oscillator design capable of supporting adaptation intended to restore control precision in damaged or imperfectly manufactured insect-scale flapping-wing micro air vehicles.It will also present preliminary experimental results demonstrating that previously used basis function sets may have been too large and that significantly improved learning times may be achieved by judiciously culling the oscillator search space.The paper will conclude with a discussion of the application of this adaptive,evolvable oscillator to full vehicle control as well as the consideration of longer term goals and requirements.

  4. Strategic flexibility

    OpenAIRE

    Kim, KiHyung

    2014-01-01

    A flexible system is defined as one that can change the entity's stance, capability or status reacting to a change of the entity's environment. Flexibility has gathered the attention of academic researchers and industry practitioners as an efficient approach to cope with today's volatile environment. As the environments become more unpredictable and volatile, it is imperative for a flexible system to respond quickly to a change in its circumstance. How much flexibility is embedded into the sy...

  5. Flexible Ablators

    Science.gov (United States)

    Stackpoole, Margaret M. (Inventor); Ghandehari, Ehson M. (Inventor); Thornton, Jeremy J. (Inventor); Covington, Melmoth Alan (Inventor)

    2017-01-01

    A low-density article comprising a flexible substrate and a pyrolizable material impregnated therein, methods of preparing, and devices using the article are disclosed. The pyrolizable material pyrolizes above 350 C and does not flow at temperatures below the pyrolysis temperature. The low-density article remains flexible after impregnation and continues to remain flexible when the pyrolizable material is fully pyrolized.

  6. Flexible Software for Flexible Scheduling

    Science.gov (United States)

    Economou, Frossie; Jenness, Tim; Tilanus, Remo P. J.; Hirst, Paul; Adamson, Andy J.; Rippa, Mathew; Delorey, Kynan K.; Isaak, Kate G.

    The JAC Observation Management Project (OMP) provides software for the James Clerk Maxwell (JCMT) and the United Kingdom Infrared (UKIRT) telescopes that manages the life-cycle of flexibly scheduled observations. Its aim is to increase observatory efficiency under flexible (queue) scheduled observing, without depriving the principal investigator (PI) of the flexibility associated with classical scheduling.

  7. Control Closed-loop Micro-vibration Modeling and Simulation Based on Flexible Satellite Model%基于全柔性卫星模型的控制闭环微振动建模与仿真

    Institute of Scientific and Technical Information of China (English)

    葛东明; 邹元杰; 张志娟; 王泽宇

    2012-01-01

    针对高分辨率遥感卫星的微振动分析,给出了一种整星结构运动与姿态控制系统闭环的建模方法。该方法基于全柔性卫星模型,通过考虑姿态控制系统的控制律和硬件特性建立集成仿真模型,进而预测卫星在轨微振动的微振动响应和结构传递特性。文章以某遥感卫星为例,分别从开环和闭环角度给出了微振动的微振动响应和结构传递特性的结果,并进行对比分析。分析结果表明:提出的方法能够实现全柔性卫星模型的控制闭环微振动分析,相对于传统的开环仿真更接近在轨实际情况。%For the micro-vibration analysis of high resolution remote sensing satellite, a closed- loop modeling method connecting satellite structure and attitude control is presented. By building integrated simulation model based on the flexible satellite model as well as the control law and hardware properties of the attitude control system, the method can be used to predict the in-orbit response of micro-vibration signals and transfer characteristics of the satellite structure. For the example of a remote sensing satellite, the results of the time response and the structure transfer characteristics are presented and analyzed comparably, from the viewpoint of open-loop and closed loop respectively. The analysis results show that the presented method can realize the con- trol closed-loop micro-vibration analysis of the flexible satellite model, and is closer to the real case in orbit compared with the traditional open-loop simulation.

  8. Injection Moulded Micro-Optics Arrays for Quantification of Surface Bound Fluorescent Molecules in Air and Aqueous Media

    DEFF Research Database (Denmark)

    Hung, Tran Quang; Sun, Yi; Poulsen, Carl Esben;

    2015-01-01

    We have developed a disposable chip with integrated miniaturized supercritical angle fluorescent (SAF) micro optical structures for highly sensitive detection of fluorophores. The SAF structure enhances the fluorescent signal more than 40 folds compared to the signal detected by conventional micr...... refractive index thermal plastics i.e., polystyrene (PS) and cyclic olefin copolymer (COC)....

  9. Inertial Vibration Damping of a Flexible Base Manipulator

    National Research Council Canada - National Science Library

    GEORGE, Lynnane E; BOOK, Wayne J

    2003-01-01

    A rigid (micro) robot mounted serially to the tip of a long, flexible (macro) manipulator is often used to increase reach capability, but flexibility in the macromanipulator can make it susceptible to vibration...

  10. Combinatorial electrochemical cell array for high throughput screening of micro-fuel-cells and metal/air batteries

    Science.gov (United States)

    Jiang, Rongzhong

    2007-07-01

    An electrochemical cell array was designed that contains a common air electrode and 16 microanodes for high throughput screening of both fuel cells (based on polymer electrolyte membrane) and metal/air batteries (based on liquid electrolyte). Electrode materials can easily be coated on the anodes of the electrochemical cell array and screened by switching a graphite probe from one cell to the others. The electrochemical cell array was used to study direct methanol fuel cells (DMFCs), including high throughput screening of electrode catalysts and determination of optimum operating conditions. For screening of DMFCs, there is about 6% relative standard deviation (percentage of standard deviation versus mean value) for discharge current from 10to20mA/cm2. The electrochemical cell array was also used to study tin/air batteries. The effect of Cu content in the anode electrode on the discharge performance of the tin/air battery was investigated. The relative standard deviations for screening of metal/air battery (based on zinc/air) are 2.4%, 3.6%, and 5.1% for discharge current at 50, 100, and 150mA/cm2, respectively.

  11. Combinatorial electrochemical cell array for high throughput screening of micro-fuel-cells and metal/air batteries.

    Science.gov (United States)

    Jiang, Rongzhong

    2007-07-01

    An electrochemical cell array was designed that contains a common air electrode and 16 microanodes for high throughput screening of both fuel cells (based on polymer electrolyte membrane) and metal/air batteries (based on liquid electrolyte). Electrode materials can easily be coated on the anodes of the electrochemical cell array and screened by switching a graphite probe from one cell to the others. The electrochemical cell array was used to study direct methanol fuel cells (DMFCs), including high throughput screening of electrode catalysts and determination of optimum operating conditions. For screening of DMFCs, there is about 6% relative standard deviation (percentage of standard deviation versus mean value) for discharge current from 10 to 20 mAcm(2). The electrochemical cell array was also used to study tin/air batteries. The effect of Cu content in the anode electrode on the discharge performance of the tin/air battery was investigated. The relative standard deviations for screening of metal/air battery (based on zinc/air) are 2.4%, 3.6%, and 5.1% for discharge current at 50, 100, and 150 mAcm(2), respectively.

  12. Forgiveness Flexibility

    Directory of Open Access Journals (Sweden)

    Tuğba Seda Çolak

    2016-01-01

    Full Text Available Forgiveness flexibility is the skill to minimize the negative effect of an event by using cognitive, affective and behavioral skills while taking a stand at the end of an injurious process. A number of studies were conducted to test the flexibility of the structure of forgiveness. The theoretical structure, structural validity and the confirmatory factor analysis supported the theoretical structure of forgiveness flexibility. The criterion validity evaluated in similar manners was found high. Forgiveness flexibility designed as a three dimensional structure and its sub-dimensions was confirmed theoretically as the recognition of forgivenessand the internalization of forgiveness through insight and its practice.

  13. Conflicting flexibility

    NARCIS (Netherlands)

    De Jong, P.; Schaap, A.

    2011-01-01

    New buildings are designed for first users. For a sustainable approach there are many advantages in designing in flexibility and adjustability in order to enable and facilitate the other sequential users. For the first investor this flexibility is translated into improved exit values due to

  14. SCR脱硝空预器防腐及柔性接触密封改造%Anticorrosion and Flexible Contact Seal Transformation of the SCR Denitration Air Heater

    Institute of Scientific and Technical Information of China (English)

    欧阳葵

    2014-01-01

    After using SCR denitration in thermal power enterprises, low temperature corrosion will also occur on rotary air heater. In this paper the rotary air heater corrosion protection technology reform measures are studied, the principle and characteristics of flexible contact seal technology are analyzed, the modification of air heater anticor-rosion and the air leakage reduction is completed, and the seal transformation efficiency analysis is conducted. The running results show that prevent anticorrosion and flexible contact seal modification can prevent the corrosion at low temperature, reduce the air leakage in air heater, and obtain remarkable economic and social benefits.%火力发电企业在采用SCR脱硝后,回转式空预器也会发生低温腐蚀。研究了回转式空预器防腐改造技术措施,分析了柔性接触式密封技术的原理及特点,进行了空预器防腐及减小漏风改造,并进行了密封改造的效益分析。运行结果表明,经过防腐及柔性接触式密封改造后,可防止低温腐蚀,且大幅度降低空气预热器漏风,获得较显著的经济效益和社会效益。

  15. The effects of channel diameter on flow pattern, void fraction and pressure drop of two-phase air-water flow in circular micro-channels

    Energy Technology Data Exchange (ETDEWEB)

    Saisorn, Sira [Energy Division, The Joint Graduate School of Energy and Environment (JGSEE), King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand); Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

    2010-05-15

    Two-phase air-water flow characteristics are experimentally investigated in horizontal circular micro-channels. Test sections are made of fused silica. The experiments are conducted based on three different inner diameters of 0.53, 0.22 and 0.15 mm with the corresponding lengths of 320, 120 and 104 mm, respectively. The test runs are done at superficial velocities of gas and liquid ranging between 0.37-42.36 and 0.005-3.04 m/s, respectively. The flow visualisation is facilitated by systems mainly including stereozoom microscope and high-speed camera. The flow regime maps developed from the observed flow patterns are presented. The void fractions are determined based on image analysis. New correlation for two-phase frictional multiplier is also proposed for practical applications. (author)

  16. Fast step-response settling of micro electrostatic actuators operated at low air pressure using input shaping

    NARCIS (Netherlands)

    Mol, L.; Rocha, L.A.; Cretu, E.; Wolffenbuttel, R.F.

    2009-01-01

    Squeeze-film damping is highly inadequate in low-pressure systems or in systems where air pressure and/or gap dimensions are poorly defined. Input shaping has been used to circumvent the oscillations typically associated with under-damped mass-spring-damper systems and drastically decrease the settl

  17. Fast step-response settling of micro electrostatic actuators operated at low air pressure using input shaping

    NARCIS (Netherlands)

    Mol, L.; Rocha, L.A.; Cretu, E.; Wolffenbuttel, R.F.

    2009-01-01

    Squeeze-film damping is highly inadequate in low-pressure systems or in systems where air pressure and/or gap dimensions are poorly defined. Input shaping has been used to circumvent the oscillations typically associated with under-damped mass-spring-damper systems and drastically decrease the

  18. Direct quantitative analysis of phthalate esters as micro-contaminants in cleanroom air and wafer surfaces by auto-thermal desorption--gas chromatography--mass spectrometry.

    Science.gov (United States)

    Kang, Yuhao; Den, Walter; Bai, Hsunling; Ko, Fu-Hsiang

    2005-04-01

    This study established an analytical method for the trace analyses of two phthalate esters, including diethyl phthalate (DEP) and di-n-butyl phthalate (DBP), known as the major constituents of cleanroom micro-contamination detrimental to the reliability of semiconductor devices. Using thermal desorption coupled with a GC-MS system, standard tubes were prepared by delivering liquid standards pre-vaporized by a quasi-vaporizer into Tenax GR tubes for calibration. This method was capable of achieving detection limits of 0.05 microg m(-3) for 0.1 m3 air samples and 0.03 ng cm(-2) for 150-mm wafer surface density. Actual samples collected from a semiconductor cleanroom showed that the concentration of DBP in a polypropylene wafer box (0.45 microg m(-3)) was nearly four times higher than that in the cleanroom environment (0.12 microg m(-3)). The surface contamination of DBP was 0.67 ng cm(-2) for a wafer stored in the wafer box for 24 h. Furthermore, among the three types of heat-resistant O-ring materials tested, Kalrez was found to be particularly suitable for high-temperature processes in semiconductor cleanrooms due to their low emissions of organic vapors. This analytical procedure should serve as an effective monitoring method for the organic micro-contamination in cleanroom environments.

  19. COGENERATION OPPORTUNITIES TO IMPROVE THE EFFICIENCY OF MICRO HEAT POWER PLANTS BASED ON AIR COOLED INTERNAL COMBUSTION ENGINES

    Directory of Open Access Journals (Sweden)

    P. A. Shchinnikov

    2017-01-01

    Full Text Available The possibilities of operation of electric generators based on internal combustion engines with air cooling under conditions of cogeneration, when, along with the electricity, heat release in different embodiments is provided. Such facilities are usually realized on the basis of gasoline internal combustion engines (i.e. gasoline is used as a fuel. They can be used in the household, by professional builders, geologists, the military and rescuers in the area of emergencies and in areas with a lack of infrastructure. The basis of the facility is the gasoline generator Hitachi-2400 with an air-cooled power of 2.4 kW. The basic methodology for the study of microthermal power plants based on an air-cooled internal combustion engine which is based on balance equations is presented. The facility operation ensures the measurement of all temperatures and expenses of operating environments for determining heat flow in accordance with the proposed methodology. The specifications of heat exchangers for utilizing the heat of exhaust flue gases are presented. The energy diagram illustrating the useful effect of the application of various heat exchangers are plotted. Cogeneration possibilities of the facility are provided, firstly, by the release of heat with the air that cools a cylinder of the internal combustion engine, and, secondly, by the release of heat of hot water heated by utilizing the heat of the leaving flue gases, and, thirdly, in the calculated version, by the release of heat with air that is sequentially heated due to the cooling of the cylinder head and then by utilizing the heat of exhaust gases. It is demonstrated that the fuel heat utilization factor can be increased from 0.22 to 0.50–0.60, depending on the adopted technical solutions.

  20. Effect of air flow on the micro-discharge dynamics in an array of integrated coaxial microhollow dielectric barrier discharges

    Science.gov (United States)

    Nayak, Gaurav; Du, Yanjun; Brandenburg, Ronny; Bruggeman, Peter J.

    2017-03-01

    The micro-discharge properties and evolution in a 2D array of integrated coaxial microhollow dielectric barrier discharges are studied by using highly time-resolved electrical and optical diagnostics. The study is focused on the effect of the gas flow rate and gas residence time on discharge properties. The investigated integrated coaxial microhollow discharge geometry allows operating the discharge at exceptionally small residence times, which can be equal to or even smaller than the discharge period, at reasonable gas flow rates. The gas flow has an impact on gas heating, residual humidity, pre-ionization density and the densities of excited and reactive species produced by previous discharges. A unique voltage–charge plot is obtained with elongated periods without discharge activity. A very significant effect of flow on NO emission is observed that relates to the impact of flow on the NO production in these micro-discharges. Using the emission intensities of molecular bands of the second positive system of nitrogen and the first negative system of the nitrogen ion, effective reduced electric field strengths are obtained with a maximum equal to 870 Td. The reduced electric field decreases with increasing gas flow rate. This behavior is consistent with the reduction of the overall discharge intensity due to a reduced amount of charges present in the discharge gap. Both the flow rate and a reduction in water impurity changing the ion mobility can be responsible for the different effective electric field distributions at the highest and no flow conditions.

  1. Flow pattern, void fraction and pressure drop of two-phase air-water flow in a horizontal circular micro-channel

    Energy Technology Data Exchange (ETDEWEB)

    Saisorn, Sira [Energy Division, The Joint Graduate School of Energy and Environment (JGSEE), King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand); Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Laboratory (FUTURE), Department of Mechanical Engineering, King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

    2008-01-15

    Adiabatic two-phase air-water flow characteristics, including the two-phase flow pattern as well as the void fraction and two-phase frictional pressure drop, in a circular micro-channel are experimentally studied. A fused silica channel, 320 mm long, with an inside diameter of 0.53 mm is used as the test section. The test runs are done at superficial velocity of gas and liquid ranging between 0.37-16 and 0.005-3.04 m/s, respectively. The flow pattern map is developed from the observed flow patterns i.e. slug flow, throat-annular flow, churn flow and annular-rivulet flow. The flow pattern map is compared with those of other researchers obtained from different working fluids. The present single-phase experiments also show that there are no significant differences in the data from the use of air or nitrogen gas, and water or de-ionized water. The void fraction data obtained by image analysis tends to correspond with the homogeneous flow model. The two-phase pressure drops are also used to calculate the frictional multiplier. The multiplier data show a dependence on flow pattern as well as mass flux. A new correlation of two-phase frictional multiplier is also proposed for practical application. (author)

  2. Flexible Sigmoidoscopy

    Science.gov (United States)

    ... Task Force (USPSTF). Most doctors recommend colonoscopy to screen for colon cancer because colonoscopy shows the entire colon and can remove colon polyps. However, preparing for and performing a flexible sigmoidoscopy may take less time and you may ...

  3. Design/Development of Mini/Micro Air Vehicles through Modelling and Simulation: Case of an Autonomous Quadrotor

    Directory of Open Access Journals (Sweden)

    Nitin K. Gupta

    2011-07-01

    Full Text Available Normal 0 MicrosoftInternetExplorer4 Design and development of an autonomous quadrotor micro aerial vehicle is undertaken following a systematic approach. A fairly detailed model was constructed and simulations were then carried out with the purpose of refining the baseline design, building a controller, and testing the flying qualities of the vehicle on a ground-based flight simulator. Following this, a smooth transition to rig and flight testing has been enabled in a cost- and time-effective manner, meeting all the design requirements.Defence Science Journal, 2011, 61(4, pp.337-345, DOI:http://dx.doi.org/10.14429/dsj.61.1086

  4. Neutral gas temperature maps of the pin-to-plate Argon micro discharge into the ambient air

    CERN Document Server

    Xu, Shaofeng; Majeed, Asif

    2015-01-01

    This study is designed to explore the two dimensional temperature maps of the atmospheric argon discharge consisting of pin-to-plane electrodes supplied by a high voltage DC source. After checking the stability of the micro discharge, the two dimensional image plane focused by a quartz lens was scanned by the fiber probe driven by a 3D Mobile Platform. The rotational and vibrational temperatures are calculated using nitrogen emissions collected by the high resolution spectrometer and high sensitive intensified charge coupled device (ICCD). The rotational temperature varies from 1558.15 K to 2621.14 K and vibrational temperature varies from 3010.38 K to 3774.69 K, indicating a great temperature gradient due to small discharge size. The temperature maps show a lateral expansion and a sharp truncation in the radial direction. A double layers discharge is identified, where an arc discharge coats the glow discharge.

  5. Fast step-response settling of micro electrostatic actuators operated at low air pressure using input shaping

    Science.gov (United States)

    Mol, L.; Rocha, L. A.; Cretu, E.; Wolffenbuttel, R. F.

    2009-07-01

    Squeeze-film damping is highly inadequate in low-pressure systems or in systems where air pressure and/or gap dimensions are poorly defined. Input shaping has been used to circumvent the oscillations typically associated with under-damped mass-spring-damper systems and drastically decrease the settling time. The proposed method does not rely on feedback but solely on the system dynamics. The required input signal is derived analytically from the differential equation describing the system. The resulting device response is simulated and experimentally verified on an electrostatically actuated microstructure. Settling occurs even faster than for an equivalent critically damped system.

  6. Improving tuberculosis infection control practice and micro-bial air quality in a general hospital after intervention

    Institute of Scientific and Technical Information of China (English)

    Pipat Luksamijarulkul; Jiraporn Khumsri; Pisit Vatthanasomboon; Pornapa Aiumlaor

    2009-01-01

    Objective:Hospital personnel,especially nurses are at risk for tuberculosis(TB)infection and the intervention for reducing the risk should be established.Methods:To compare the TB infection control practices and stand-ard precaution in 154 registered nurses and auxiliary nurses working in risk wards.Additionally,microbial air quality in the studied wards was investigated before and after implementation of an intervention including two-day training program on TB infection control and standard precaution practices and managing the ward environ-ments.Results:Post-intervention,the percentage of studied nurses who always practiced increased in every i-tem of TB infection control practice (6 items)and standard precaution (9 items)when compared with the pre-intervention period.Both mean scores were significantly higher than those before intervention (5.0 ±1.0 vs 4. 4 ±1.1,and 7.6 ±1.3 vs 6.7 ±1.5,P 500 cfu /m3 ).Conclusion:Two-day training program and management of the ward environment could improve the scores of TB infection control practices and the standard precaution among studied nurses and reduce the microbial counts in air samples col-lected from the studied wards.

  7. Piping Flexibility

    Science.gov (United States)

    1978-01-01

    A NASA computer program aids Hudson Engineering Corporation, Houston, Texas, in the design and construction of huge petrochemical processing plants like the one shown, which is located at Ju'aymah, Saudi Arabia. The pipes handling the flow of chemicals are subject to a variety of stresses, such as weight and variations in pressure and temperature. Hudson Engineering uses a COSMIC piping flexibility analysis computer program to analyze stresses and unsure the necessary strength and flexibility of the pipes. This program helps the company realize substantial savings in reduced engineering time.

  8. 2-DOF并联柔性结构微动平台的新构型及尺寸优化%New Configuration and Size Optimization of a 2-DOF Parallel Micro-positioning Stage with Flexible Structure

    Institute of Scientific and Technical Information of China (English)

    崔玉国; 阮超; 马剑强; 郑绍雍; 淳华

    2016-01-01

    In order to obtain 2-DOF parallel flexible-structure micro-positioning stage with good static and dynamic char-acteristics, a new stage configuration is proposed, which is optimized by a size optimization method. The principle and modified morphology of the Stewart parallel mechanism is applied to designing the stage structure, and a new configuration with elastic elements of dual arc thin plates is designed for 2-DOF parallel flexible-structure micro-positioning stage. The stiffness expression in all directions of the stage is given with the deformation theory of curved cantilever beam. And through summating the stiffness expression in all directions, a unified objective function for size optimization of the stage is estab-lished by weighted combination approach. Then the mathematical model is solved using sequential quadratic programming (SQP). The static and dynamic characteristics of the stage before and after optimization are tested experimentally. The results show that: the displacements of the optimized stage in x and y directions are 22.98 µm and 23.15 µm at the driving voltage of 150 V, meeting the design requirements. The natural frequencies of the optimized stage in x, y, z directions are 1.731 kHz, 1.722 kHz and 1.725 kHz. The dynamic characteristics of the optimized stage are more equal in each direction. The response time of the optimized stage in x and y directions at the input step force of 50 N are 18 ms and 20 ms, which are shorter obviously after optimization.%为了获得具有良好静、动态特性的2-DOF并联柔性结构微动平台,在给出平台新构型的基础上,对其进行尺寸优化设计.基于Stewart并联机构思想并对其进行相应的结构改变,设计出了具有对称双圆弧薄板式弹性单元体的2-DOF并联柔性结构微动平台新构型.采用悬臂曲梁变形理论给出了平台各方向的刚度表达式,进而通过加权组合法建立了综合考虑各方向刚

  9. Identification and Analysis of C. annuum microRNAs by High-throughput Sequencing and Their Association with High Temperature and High Air Humidity Stress

    Directory of Open Access Journals (Sweden)

    Xiao-wan Xu

    2015-12-01

    Full Text Available MicroRNAs (miRNAs play an important role in many developmental processes and stress responses in plants. In this study, tolerant hot pepper cultivar 'R597' (CaR and sensitive cultivar 'S590' (CaS were used to detected differentially expressed miRNAs under high temperatures and high air humidity. The length distribution of obtained small RNAs was significantly different between libraries. There were a total of 71 miRNA families identified in two genotypes, and 24 conserved miRNA families were detected in all four sRNA libraries. MIR166, MIR156/157, MIR167, MIR168, MIR2118, and MIR5301 were highly expressed in four libraries, and 93 miRNAs had a species-specific expression. Among them, 60 miRNAs were preferentially expressed in S590 leaves and 33 miRNAs were preferentially expressed in R597 leaves. Mostly miRNAs were less-conserved miRNAs. The most abundant miRNAs with different expressions between two pepper species was miR6149b, which exhibited a high level (read count 42,443 in CaSCK but no expressed in CaRCK. We found 650 (CaRCK, 1054 (CaRHH, 914 (CaSCK, 1045 (CaSHH potential targets for 92 (CaRCK, 124 (CaRHH, 128 (CaSCK, 117 (CaSHH hot pepper miRNAs, respectively. These findings facilitate in better understanding of the molecular mechanism underlying high temperature and high air humidity condition in different pepper genotypes.

  10. Force generation and wing deformation characteristics of a flapping-wing micro air vehicle 'DelFly II' in hovering flight.

    Science.gov (United States)

    Percin, M; van Oudheusden, B W; de Croon, G C H E; Remes, B

    2016-05-19

    The study investigates the aerodynamic performance and the relation between wing deformation and unsteady force generation of a flapping-wing micro air vehicle in hovering flight configuration. Different experiments were performed where fluid forces were acquired with a force sensor, while the three-dimensional wing deformation was measured with a stereo-vision system. In these measurements, time-resolved power consumption and flapping-wing kinematics were also obtained under both in-air and in-vacuum conditions. Comparison of the results for different flapping frequencies reveals different wing kinematics and deformation characteristics. The high flapping frequency case produces higher forces throughout the complete flapping cycle. Moreover, a phase difference occurs in the variation of the forces, such that the low flapping frequency case precedes the high frequency case. A similar phase lag is observed in the temporal evolution of the wing deformation characteristics, suggesting that there is a direct link between the two phenomena. A considerable camber formation occurs during stroke reversals, which is mainly determined by the stiffener orientation. The wing with the thinner surface membrane displays very similar characteristics to the baseline wing, which implies the dominance of the stiffeners in terms of providing rigidity to the wing. Wing span has a significant effect on the aerodynamic efficiency such that increasing the span length by 4 cm results in a 6% enhancement in the cycle-averaged X-force to power consumption ratio compared to the standard DelFly II wings with a span length of 28 cm.

  11. Flexibility conflict?

    NARCIS (Netherlands)

    Delsen, L.W.M.

    2002-01-01

    The chapter deals with the presupposed conflict of interests between employers and employees resulting from a decoupling of operating hours and working times. It starts from the notion that both long operating hours and flexibility are relative concepts. As there is some discretion, the ultimate

  12. Flexible Consumption

    DEFF Research Database (Denmark)

    Holm Jacobsen, Peter; Pallesen, Trine

    This report presents the first findings from our qualitative study of consumer behaviour vis-à-vis flexible consumption. The main of objective of this report is to present our first round of data from Bornholm, and to assist the design of products/services designed in WP6. In the report, we adopt...

  13. Singlet delta oxygen production in a 2D micro-discharge array in air: effect of gas residence time and discharge power

    Science.gov (United States)

    Nayak, Gaurav; Santos Sousa, João; Bruggeman, Peter J.

    2017-03-01

    The production of singlet delta oxygen (O2(a 1Δg)) is of growing interest for many applications. We report on the measurement of O2(a 1Δg) and ozone (O3) in a room temperature atmospheric pressure discharge in dry air. The plasma source is a 2D array of micro-discharges generated by an alternating current voltage at 20 kHz. The study focuses on the effect of gas flow through the discharge. The maximum investigated flow rate allows reducing the gas residence time in the discharge zone to half the discharge period. Results indicate that the residence time and discharge power have a major effect on the O2(a 1Δg) production. Different O2(a 1Δg) density dependencies on power are observed for different flow rates. Effects of collisional quenching on the as-produced and measured O2(a 1Δg) densities are discussed. The flow rate also allows for control of the O2(a 1Δg) to O3 density ratio in the effluent from 0.7 to conditions of pure O3.

  14. Nonhomogeneous surface properties of parylene-C film etched by an atmospheric pressure He/O2 micro-plasma jet in ambient air

    Science.gov (United States)

    Wang, Tao; Yang, Bin; Chen, Xiang; Wang, Xiaolin; Yang, Chunsheng; Liu, Jingquan

    2016-10-01

    Surface properties of parylene-C film etched by an atmospheric pressure He/O2 micro-plasma jet in ambient air were investigated. The morphologies and chemical compositions of the etched surface were analyzed by optical microscopy, SEM, EDS, XPS and ATR-FTIR. The microscopy and SEM images showed the etched surface was nonhomogeneous with six discernable ring patterns from the center to the outside domain, which were composed of (I) a central region; (II) an effective etching region, where almost all of the parylene-C film was removed by the plasma jet with only a little residual parylene-C being functionalized with carboxyl groups (Cdbnd O, Osbnd Cdbnd O-); (III) an inner etching boundary; (IV) a middle etching region, where the film surface was smooth and partially removed; (V) an outer etching boundary, where the surface was decorated with clusters of debris, and (VI) a pristine parylene-C film region. The analysis of the different morphologies and chemical compositions illustrated the different localized etching process in the distinct regions. Besides, the influence of O2 flow rate on the surface properties of the etched parylene-C film was also investigated. Higher volume of O2 tended to weaken the nonhomogeneous characteristics of the etched surface and improve the etched surface quality.

  15. Trapping the Pasture Odorscape Using Open-Air Solid-Phase Micro Extraction, a Tool to Assess Grassland Value.

    Directory of Open Access Journals (Sweden)

    Agnès Cornu

    Full Text Available Besides supporting cattle feeding, grasslands are home to a diversity of plants and insects that interact with each other by emitting volatile compounds. The aim of this work was to develop a method to determine permanent grassland odorscape and relate it to flower-visiting insects. Two grasslands were chosen for their contrasting levels of botanical diversity, resulting from differing grazing managements. Measurements were made over two periods of three consecutive days at the beginning of grazing, and just after the cows had left the plots. Volatile compounds were trapped using solid-phase microextraction (SPME fibers exposed eight hours a day in three exclosures per plot, and then analyzed by gas-chromatography-mass spectrometry (GC-MS. Insects were trapped using pan traps and a net, sorted and counted. The open air SPME method yielded volatile compound profiles that were richer than maize field profiles, comprising the common green leaf volatiles (GLV and more specific ones. Differences between the odorscapes of the two grasslands were found, but they were not as marked as expected from their botanical composition. By contrast, there were sharp differences between the two periods, resulting from the combined effects of changes in weather conditions, plant phenological stage and grazing progress. Several correlations between insect counts and volatile compounds were found. Although their correlation coefficients were low, some of them were confirmed when tested by Spearman rank correlation, and could be logically explained. This method of grassland odorscape deserves to be developed because it can provide information on many aspects of grassland function and on the stresses that grassland plants undergo.

  16. A CFD study of hygro-thermal stresses distribution in tubular-shaped ambient air-breathing PEM micro fuel cell during regular cell operation

    Directory of Open Access Journals (Sweden)

    Maher A.R. Sadiq Al-Baghdadi

    2010-03-01

    Full Text Available The need for improved lifetime of air-breathing proton exchange membrane (PEM fuel cells for portable applications necessitates that the failure mechanisms be clearly understood and life prediction models be developed, so that new designs can be introduced to improve long-term performance. An operating air-breathing PEM fuel cell has varying local conditions of temperature, humidity. As a result of in the changes in temperature and moisture, the membrane, GDL and bipolar plates will all experience expansion and contraction. Because of the different thermal expansion and swelling coefficients between these materials, hygro-thermal stresses are introduced into the unit cell during operation. In addition, the non-uniform current and reactant flow distributions in the cell result in non-uniform temperature and moisture content of the cell which could in turn, potentially causing localized increases in the stress magnitudes, and this leads to mechanical damage, which can appear as through-the-thickness flaws or pinholes in the membrane, or delaminating between the polymer membrane and gas diffusion layers. Therefore, in order to acquire a complete understanding of these damage mechanisms in the membranes and gas diffusion layers, mechanical response under steady-state hygro-thermal stresses should be studied under real cell operation conditions. A three-dimensional, multi–phase, non-isothermal computational fluid dynamics model of a novel, tubular, ambient air-breathing, proton exchange membrane micro fuel cell has been developed and used to investigate the displacement, deformation, and stresses inside the whole cell, which developed during the cell operation due to the changes of temperature and relative humidity. The behaviour of the fuel cell during operation has been studied and investigated under real cell operating conditions. In addition to the new and complex geometry, a unique feature of the present model is to incorporate the effect of

  17. Flexible Stamp for Nanoimprint Lithography

    DEFF Research Database (Denmark)

    Nielsen, Theodor; Pedersen, Rasmus H.; Hansen, Ole

    2005-01-01

    The design, fabrication and performance of a flexible silicon stamp for homogenous large area nanoimprint lithography (NIL) are presented. The flexible stamp is fabricated by bulk semiconductor micro machining of a 4-inch silicon wafer and consists of thick anchor like imprint areas connected...... by membranes. The bending stiffness difference between the imprint areas and the membranes ensures that the deformation of the stamp during the imprint process mainly takes place in the membranes, leaving the imprint structures unaffected. By this design the strong demand to the parallelism between stamp...

  18. Flexible isotopy classification of flexible links

    OpenAIRE

    Björklund, Johan

    2012-01-01

    In this paper we define and study flexible links and flexible isotopy in projective space. Flexible links are meant to capture the topological properties of real algebraic links. We classify all flexible links up to flexible isotopy using Ekholms interpretation of Viros encomplexed writhe.

  19. Flexible Capitalism

    DEFF Research Database (Denmark)

    Approaching “work” as at heart a practice of exchange, this volume explores sociality in work environments marked by the kind of structural changes that have come to define contemporary “flexible” capitalism. It introduces anthropological exchange theory to a wider readership, and shows how...... the perspective offers new ways to enquire about the flexible capitalism’s social dimensions. The essays contribute to a trans-disciplinary scholarship on contemporary economic practice and change by documenting how, across diverse settings, “gift-like” socialities proliferate, and even sustain the intensified...... flexible commoditization that more commonly is touted as tearing social relations apart. By interrogating a keenly debated contemporary work regime through an approach to sociality rooted in a rich and distinct anthropological legacy, the volume also makes a novel contribution to the anthropological...

  20. 三轴气浮台挠性航天器动力学模拟方法研究%Method for Flexible Satellite Dynamics Simulation on Three-Axis Air-Bearing Table

    Institute of Scientific and Technical Information of China (English)

    陈欢龙; 周军; 刘莹莹; 牟小刚

    2011-01-01

    Because of the Earth gravity, flexible appendages cannot be fixed on the table, three-axis air-bearing table cannot be used to simulate attitude dynamics of a flexible satellite, a method is developed by using momentum wheels to simulate the vibrational disturbance torque of satellite flexible appendages on three-axis air-bearing table. By designing a tracking controller, the air-bearing table' s angular velocity is used to track reference dynamics of the flexible satellite, the momentum wheel provide the control torque, i.e. the vibration disturbance torque to be simulated. The theory and mathematial simulations show: ( 1 ) This method can simulate low-order flexible vibration disturbance torque well; (2) In theory, the greater the controller gain, the higher frequency of disturbance torque can be simulated. However, because of measurement noise, the feedback gain cannot be too great; (3) Due to the inherent de]ay of controller and actuator, there is phase delay between the emulational disturbance torque and real disturbance torque. Therefore, a lead-lag correction network is introduced to reduce the effect of phase delay.%本文研究利用气浮台上的动量轮执行机构,模拟卫星上挠性附件振动产生的干扰力矩的卫星物理仿真实验方法,以克服三轴气浮台不能直接安装挠性附件进行仿真的局限性.本实验方法通过设计一个跟踪控制器,令气浮台的姿态角速度跟踪挠性卫星参考动力学,并由动量轮产生控制力矩,该力矩即是实验模拟的挠性振动干扰力矩.理论和仿真研究表明:(1)本文提出的挠性干扰力矩模拟方法可以较好地模拟低阶挠性振动干扰力矩;(2)理论上当控制器的增益参数越大,系统能够模拟的干扰力矩频率就越大,但是由于测量噪声的影响,反馈增益不能选得过大;(3)本方法模拟的干扰力矩与真实干扰力矩存在一定的相位延迟,这是由于控制器和执行机构的固有延迟造成的.

  1. Flexible HVAC System for Lab or Classroom.

    Science.gov (United States)

    Friedan, Jonathan

    2001-01-01

    Discusses an effort to design a heating, ventilation, and air conditioning system flexible enough to accommodate an easy conversion of classrooms to laboratories and dry labs to wet labs. The design's energy efficiency and operations and maintenance are examined. (GR)

  2. Flexible HVAC System for Lab or Classroom.

    Science.gov (United States)

    Friedan, Jonathan

    2001-01-01

    Discusses an effort to design a heating, ventilation, and air conditioning system flexible enough to accommodate an easy conversion of classrooms to laboratories and dry labs to wet labs. The design's energy efficiency and operations and maintenance are examined. (GR)

  3. Error analysis and assessment of unsteady forces acting on a flapping wing micro air vehicle: free flight versus wind-tunnel experimental methods.

    Science.gov (United States)

    Caetano, J V; Percin, M; van Oudheusden, B W; Remes, B; de Wagter, C; de Croon, G C H E; de Visser, C C

    2015-08-20

    An accurate knowledge of the unsteady aerodynamic forces acting on a bio-inspired, flapping-wing micro air vehicle (FWMAV) is crucial in the design development and optimization cycle. Two different types of experimental approaches are often used: determination of forces from position data obtained from external optical tracking during free flight, or direct measurements of forces by attaching the FWMAV to a force transducer in a wind-tunnel. This study compares the quality of the forces obtained from both methods as applied to a 17.4 gram FWMAV capable of controlled flight. A comprehensive analysis of various error sources is performed. The effects of different factors, e.g., measurement errors, error propagation, numerical differentiation, filtering frequency selection, and structural eigenmode interference, are assessed. For the forces obtained from free flight experiments it is shown that a data acquisition frequency below 200 Hz and an accuracy in the position measurements lower than ± 0.2 mm may considerably hinder determination of the unsteady forces. In general, the force component parallel to the fuselage determined by the two methods compares well for identical flight conditions; however, a significant difference was observed for the forces along the stroke plane of the wings. This was found to originate from the restrictions applied by the clamp to the dynamic oscillations observed in free flight and from the structural resonance of the clamped FWMAV structure, which generates loads that cannot be distinguished from the external forces. Furthermore, the clamping position was found to have a pronounced influence on the eigenmodes of the structure, and this effect should be taken into account for accurate force measurements.

  4. Successful production of piglets derived from expanded blastocysts vitrified using a micro volume air cooling method without direct exposure to liquid nitrogen.

    Science.gov (United States)

    Misumi, Koji; Hirayama, Yuri; Egawa, Sachiko; Yamashita, Shoko; Hoshi, Hiroyoshi; Imai, Kei

    2013-12-17

    This study was conducted to clarify the feasibility of newly developed vitrification techniques for porcine embryos using the micro volume air cooling (MVAC) method without direct contact with liquid nitrogen (LN₂). Expanded blastocysts were vitrified in a solution containing 6 M ethylene glycol, 0.6 M trehalose and 2% (wt/vol) polyethylene glycol in 10% HEPES-buffered PZM-5. The blastocysts were collected from gilts and vitrified using the new device (MVAC) or a Cryotop (CT). Blastocysts were stored in LN₂ for at least 1 month. After warming, cryoprotective agents were removed using a single step. Survival of the embryos was assessed by in vitro culture (Experiment 1) and by embryo transfer to recipients (Experiment 2). In Experiment 1, the embryos vitrified by the MVAC or CT and fresh embryos without vitrification (Control) were used. The survival rates of embryos in the MVAC, CT and Control groups were 88.9% (32/36), 91.7% (33/36) and 100% (34/34), respectively, after 48 h culture, and the hatching rates of embryos after 48 h incubation were 69.4% (25/36), 63.9% (23/36) and 94.1% (32/34), respectively. In Experiment 2, 64 vitrified embryos were transferred to 5 recipient gilts, and 8 healthy piglets were produced from 3 recipients in the MVAC group. Similarly, 66 vitrified embryos were transferred to 5 recipient gilts, and 9 healthy piglets were produced from 2 recipients in the CT group. These results indicated that porcine expanded blastocysts can be cryopreserved using the MVAC method without potential pathogen contamination from LN₂.

  5. The relationship between oxygen consumption rate and viability of in vivo-derived pig embryos vitrified by the micro volume air cooling method.

    Science.gov (United States)

    Sakagami, N; Nishida, K; Misumi, K; Hirayama, Y; Yamashita, S; Hoshi, H; Misawa, H; Akiyama, K; Suzuki, C; Yoshioka, K

    2016-01-01

    The aim of this study was to assess the viability of vitrified-warmed in vivo-derived pig embryos after measuring the oxygen consumption rate. Six days after artificial insemination, blastocysts were collected from gilts and vitrified by the micro volume air cooling method. The oxygen consumption rate was measured in 60 vitrified-warmed embryos, which were then cultured for 48h to assess the viability. The survival (re-expansion) rate of embryos after warming was 85.0%. The average oxygen consumption rate of embryos immediately after warming was greater in embryos which could re-expand during subsequent culture (F=0.75±0.04) than that in those which failed to re-expand (F=0.33±0.05). Moreover, the oxygen consumption rate of vitrified-warmed embryos was greater in the hatched (F=0.88±0.06) than that in the not-hatched group (F=0.53±0.04). When the oxygen consumption rate of the vitrified-warmed embryos and the numbers of viable and dead cells in embryos were determined, there was a positive correlation between the oxygen consumption rate and the number of live cells (Pconsumption rate were surgically transferred into uterine horns of two recipients. Both of the recipients become pregnant and farrowed 12 healthy piglets. These results demonstrate that the oxygen consumption rate of vitrified-warmed pig embryos can be related to the number of live cells and that the measurement of oxygen consumption of embryos after cryopreservation may be useful for estimating embryo survivability.

  6. Flexible Capitalism

    DEFF Research Database (Denmark)

    Approaching “work” as at heart a practice of exchange, this volume explores sociality in work environments marked by the kind of structural changes that have come to define contemporary “flexible” capitalism. It introduces anthropological exchange theory to a wider readership, and shows how...... the perspective offers new ways to enquire about the flexible capitalism’s social dimensions. The essays contribute to a trans-disciplinary scholarship on contemporary economic practice and change by documenting how, across diverse settings, “gift-like” socialities proliferate, and even sustain the intensified...

  7. Copper Nanowires and Their Applications for Flexible, Transparent Conducting Films: A Review

    Directory of Open Access Journals (Sweden)

    Vu Binh Nam

    2016-03-01

    Full Text Available Cu nanowires (NWs are attracting considerable attention as alternatives to Ag NWs for next-generation transparent conductors, replacing indium tin oxide (ITO and micro metal grids. Cu NWs hold great promise for low-cost fabrication via a solution-processed route and show preponderant optical, electrical, and mechanical properties. In this study, we report a summary of recent advances in research on Cu NWs, covering the optoelectronic properties, synthesis routes, deposition methods to fabricate flexible transparent conducting films, and their potential applications. This review also examines the approaches on protecting Cu NWs from oxidation in air environments.

  8. Micro Engineering

    DEFF Research Database (Denmark)

    Alting, Leo; Kimura, F.; Hansen, Hans Nørgaard

    2003-01-01

    The paper addresses the questions of how micro products are designed and how they are manufactured. Definitions of micro products and micro engineering are discussed and the presentation is aimed at describing typical issues, possibilities and tools regarding design of micro products. The implica......The paper addresses the questions of how micro products are designed and how they are manufactured. Definitions of micro products and micro engineering are discussed and the presentation is aimed at describing typical issues, possibilities and tools regarding design of micro products...

  9. 微通道换热器在制冷空调系统中的应用分析%Application analysis for micro - channel heat exchanger in refrigeration and air - conditioning system

    Institute of Scientific and Technical Information of China (English)

    张超; 刘婷; 周光辉

    2011-01-01

    The implementation of new energy consumption standard on June 1, 2010 has further promoted the refrigeration and air - conditioning industry upgrade. Micro - channel heat exchanger with many characteristics such as small volume, light weight, compact structure, sustaining high operating pressure, low thermal resistance and good effect on heat transfer has been gradually applied in automotive, household and commercial refrigeration and air - conditioning system. However, the domestic studies in this field start later than the foreign one, and the theoretical and experimental research are scarce. In this paper, the previous research of micro - channel heat exchanger in refrigeration and air - conditioning system was summarized and analyzed. And the difficulties in the field were pointed out, which could provide references for further application of micro - channel heat exchanger in refrigeration and air - conditioning system.%2010年6月1日实施的新能耗标准进一步推动了制冷空调行业的升级,微通道换热器以其体积小、重量轻、结构紧凑、耐高压、热阻低、换热效果好等特点开始逐步在汽车制冷空调系统、家用和商用制冷空调系统中得以应用.然而,国内在该领域的研究比国外起步晚,理论和实验研究都比较缺乏.文中对微通道换热器在制冷空调系统中的应用研究进行了总结分析,指出了该研究领域的研究热点,为其进一步的应用研究提供了参考.

  10. Thermal performance of new flat plate solar air heater based on micro-heat pipe arrays (MHPA)%微热管阵列式太阳能平板空气集热器集热性能

    Institute of Scientific and Technical Information of China (English)

    朱婷婷; 刁彦华; 赵耀华; 马骋; 李凤飞

    2016-01-01

    In common types of flat-plate solar air heaters, the uneven flow and heat exchange between air and an absorber plate poses a problem. To resolve this problem, this paper proposed a novel type of flat-plate solar air heater based on micro-heat pipe arrays (MHPA). An investigation was carried out on the design, thermal performance and flow resistance characteristic of the novel heater based on micro-heat pipe arrays. The new air collector consists of 15 MHPAs with V-shaped fins attached to the heat release (condenser) section, absorber film, insulation board, bottom plate, and air ventilation and heat exchange section. The components of the heater include the toughened glass cover, air layer (35 mm), MHPA-absorber plate, thermal insulation layer, and the back board. Solar energy is absorbed by the MHPA evaporator section with the organic combination of high efficiency absorber film, which formed a heat pipe effect within each micro heat pipe arrays. The heat has been released to the air in the ventilation and heat exchange section of the heater, whereas the air was eventually warmed. Simultaneously, the working medium in MHPA proceeds continuous phase transition cycle and continuously passes solar radiation heat to air in the air duct with high efficiency. The MHPA heat-absorbing plate core can realize the whole area of heat absorption, high efficient heat transmission, and large surface of heat release. The total solar energy is received by the heater, and some energy is transferred to the air flow in the air duct as useful energy; the remaining energy is lost mainly through the glass cover, frames, bottom plate, and air duct. The heat loss through the frames and the air duct can be ignored because of good heat preservation condition. So the glass cover becomes the main source of heat loss. Thermal analysis shows that heat loss through the glass cover occupies the largest proportion of the total heat loss of the heater.To test the new heater thermal efficiency and

  11. Micro Engineering

    DEFF Research Database (Denmark)

    Alting, Leo; Kimura, F.; Hansen, Hans Nørgaard

    2003-01-01

    The paper addresses the questions of how micro products are designed and how they are manufactured. Definitions of micro products and micro engineering are discussed and the presentation is aimed at describing typical issues, possibilities and tools regarding design of micro products. The implica...

  12. Soft, flexible micromanipulators comprising polypyrrole trilayer microactuators

    Science.gov (United States)

    Khaldi, Alexandre; Maziz, Ali; Alici, Gursel; Spinks, Geoffrey M.; Jager, Edwin W. H.

    2015-04-01

    Within the areas of cell biology, biomedicine and minimal invasive surgery, there is a need for soft, flexible and dextrous biocompatible manipulators for handling biological objects, such as single cells and tissues. Present day technologies are based on simple suction using micropipettes for grasping objects. The micropipettes lack the possibility of accurate force control, nor are they soft and compliant and may thus cause damage to the cells or tissue. Other micromanipulators use conventional electric motors however the further miniaturization of electrical motors and their associated gear boxes and/or push/pull wires has reached its limits. Therefore there is an urgent need for new technologies for micromanipulation of soft biological matter. We are developing soft, flexible micromanipulators such as micro- tweezers for the handling and manipulation of biological species including cells and surgical tools for minimal invasive surgery. Our aim is to produce tools with minimal dimensions of 100 μm to 1 mm in size, which is 1-2 orders of magnitude smaller than existing technology. We present newly developed patterning and microfabrication methods for polymer microactuators as well as the latest results to integrate these microactuators into easy to use manipulation tools. The outcomes of this study contribute to the realisation of low-foot print devices articulated with electroactive polymer actuators for which the physical interface with the power source has been a significant challenge limiting their application. Here, we present a new bottom-up microfabrication process. We show for the first time that such a bottom-up fabricated actuator performs a movement in air. This is a significant step towards widening the application areas of the soft microactuators.

  13. Modeling and Verification of Hybrid Energy Storage System Based on Micro Compressed Air Energy Storage%基于微型压缩空气储能的混合储能系统建模与实验验证

    Institute of Scientific and Technical Information of China (English)

    王成山; 武震; 杨献莘; 张书槐; 刘一欣

    2014-01-01

    The micro compressed air energy storage system is a new type of energy storage systems capable of being combined with flywheel to form a hybrid energy storage system.The structure and principle of a hybrid energy storage system based on micro compressed air energy storage is described.The governor system model of micro compressed air energy storage is proposed based on the experimental data,which simulates the dynamics of pressure,temperature,valve,and turbine and so on.Finally,a comparison between experimental data and simulation results is given to verify the applicability and effectiveness of the proposed model. This work is supported by National Basic Research Program of China(973 Program)(No.2009CB219700).%微型压缩空气储能是一种新型的储能技术,可以与飞轮等组成混合储能系统。文中介绍了基于微型压缩空气储能的混合储能系统的结构及工作原理,根据现有设备的实验结果提出了压缩空气储能原动部分的数学模型,包括压缩空气压力、温度、阀门、透平等环节,并通过拟合的方法进行参数辨识。最后,搭建了混合储能系统的仿真算例,并通过仿真与实验数据的对比验证了模型的适用性和有效性。

  14. Framework for Flexible Security in Group Communications

    Science.gov (United States)

    McDaniel, Patrick; Prakash, Atul

    2006-01-01

    The Antigone software system defines a framework for the flexible definition and implementation of security policies in group communication systems. Antigone does not dictate the available security policies, but provides high-level mechanisms for implementing them. A central element of the Antigone architecture is a suite of such mechanisms comprising micro-protocols that provide the basic services needed by secure groups.

  15. Flexible Electronics Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Flexible Electronics Research Facility designs, synthesizes, tests, and fabricates materials and devices compatible with flexible substrates for Army information...

  16. Micro Vision

    OpenAIRE

    Ohba, Kohtaro; OHARA, Kenichi

    2007-01-01

    In the field of the micro vision, there are few researches compared with macro environment. However, applying to the study result for macro computer vision technique, you can measure and observe the micro environment. Moreover, based on the effects of micro environment, it is possible to discovery the new theories and new techniques.

  17. Balance and flexibility.

    Science.gov (United States)

    2003-12-01

    The 'work-life balance' and flexible working are currently key buzz terms in the NHS. Those looking for more information on these topics should visit Flexibility at www.flexibility.co.uk for a host of resources designed to support new ways of working, including information on flexible workers and flexible rostering, the legal balancing act for work-life balance and home working.

  18. A micro-coupling for micro mechanical systems

    Science.gov (United States)

    Li, Wei; Zhou, Zhixiong; Zhang, Bi; Xiao, Yunya

    2016-05-01

    The error motions of micro mechanical systems, such as micro-spindles, increase with the increasing of the rotational speed, which not only decreases the rotational accuracy, but also promotes instability and limits the maximum operational speed. One effective way to deal with it is to use micro-flexible couplings between the drive and driven shafts so as to reduce error motions of the driven shaft. But the conventional couplings, such as diaphragm couplings, elastomeric couplings, bellows couplings, and grooved couplings, etc, cannot be directly used because of their large and complicated structures. This study presents a novel micro-coupling that consists of a flexible coupling and a shape memory alloy (SMA)-based clamp for micro mechanical systems. It is monolithic and can be directly machined from a shaft. The study performs design optimization and provides manufacturing considerations, including thermo-mechanical training of the SMA ring for the desired Two-Way-Shape-Memory effect (TWSMe). A prototype micro-coupling and a prototype micro-spindle using the proposed coupling are fabricated and tested. The testing results show that the prototype micro-coupling can bear a torque of above 5 N • mm and an axial force of 8.5 N and be fitted with an SMA ring for clamping action at room temperature (15 °C) and unclamping action below-5 °C. At the same time, the prototype micro-coupling can work at a rotational speed of above 200 kr/min with the application to a high-speed precision micro-spindle. Moreover, the radial runout error of the artifact, as a substitute for the micro-tool, is less than 3 μm while that of turbine shaft is above 7 μm. It can be concluded that the micro-coupling successfully accommodates misalignment errors of the prototype micro-spindle. This research proposes a micro-coupling which is featured with an SMA ring, and it is designed to clamp two shafts, and has smooth transmission, simple assembly, compact structure, zero-maintenance and

  19. GPS-based Microenvironment Tracker (MicroTrac) Model to Estimate Time-Location of Individuals for Air Pollution Exposure Assessments: Model Evaluation in Central North Carolina

    Science.gov (United States)

    A critical aspect of air pollution exposure assessment is the estimation of the time spent by individuals in various microenvironments (ME). Accounting for the time spent in different ME with different pollutant concentrations can reduce exposure misclassifications, while failure...

  20. GPS-based Microenvironment Tracker (MicroTrac) Model to Estimate Time-Location of Individuals for Air Pollution Exposure Assessments: Model Evaluation in Central North Carolina

    Science.gov (United States)

    A critical aspect of air pollution exposure assessment is the estimation of the time spent by individuals in various microenvironments (ME). Accounting for the time spent in different ME with different pollutant concentrations can reduce exposure misclassifications, while failure...

  1. Laser direct writing of carbon/Au composite electrodes for high-performance micro-supercapacitors

    Science.gov (United States)

    Cai, Jinguang; Watanabe, Akira; Lv, Chao

    2017-02-01

    Micro-supercapacitors with small size, light weight, flexibility while maintaining high energy and power output are required for portable miniaturized electronics. The fabrication methods and materials should be cost-effective, scalable, and easily integrated to current electronic industry. Carbon materials have required properties for high-performance flexible supercapacitors, including high specific surface areas, electrochemical stability, and high electrical conductivity, as well as the high mechanical tolerance. Laser direct writing method is a non-contact, efficient, single-step fabrication technique without requirements of masks, post-processing, and complex clean room, which is a useful patterning technique, and can be easily integrated with current electronic product lines for commercial use. Previously we have reported micro-supercapacitors fabricated by laser direct writing on polyimide films in air or Ar, which showed highcapacitive performance. However, the conductivity of the carbon materials is still low for fast charge-discharge use. Here, we demonstrated the fabrication of flexible carbon/Au composite high-performance MSCs by first laser direct writing on commercial polyimide films followed by spin-coating Au nanoparticles ink and second in-situ laser direct writing using the low-cost semiconductor laser. As-prepared micro-supercapacitors show an improved conductivity and capacitance of 1.17 mF/cm2 at a high scanning rate of 10,000 mV/s, which is comparable to the reported capacitance of carbon-based micro-supercapacitors. In addition, the micro-supercapacitors have high bend tolerance and long-cycle stability.

  2. Local electrochemical impedance spectroscopy study of the influence of ageing in air and laser shock processing on the micro-electrochemical behaviour of AA2050-T8 aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Krawiec, H. [AGH, University of Science and Technology, ul. Reymonta 23, 30-059 Krakow (Poland); Vignal, V., E-mail: vincent.vignal@u-bourgogne.fr [ICB, UMR 5209 CNRS - Universite de Bourgogne, BP 47870, 21078 Dijon (France); Amar, H. [ICB, UMR 5209 CNRS - Universite de Bourgogne, BP 47870, 21078 Dijon (France); Peyre, P. [LALP, Arts et Metiers Paritech, 151 Bd de l' Hopital, 75013 Paris (France)

    2011-11-01

    In the present paper, the micro-electrochemical behaviour of AA2050-T8 in 0.1 M NaCl was first studied after polishing by means of local electrochemical impedance spectroscopy and field-emission scanning electron microscopy/electron dispersive spectroscopy (FE-SEM/EDS). The influence of ageing in air and LSP was then investigated. Ageing in air for three months led to an increase in the charge transfer resistance. This was clearly observed in sites surrounding constituent particles where the charge transfer resistance was in the order of 1 M{Omega} cm{sup 2} (instead of 10{sup -3} M{Omega} cm{sup 2} after polishing). Increased passivity around particles was confirmed from FE-SEM/EDS analysis. On the other hand, the effect of LSP on the behaviour of the matrix was found to be extremely beneficial. Both charge transfer and oxide film resistances were sharply increased to approximately 0.35 M{Omega} cm{sup 2} and 1 M{Omega} cm{sup 2}, respectively, as opposed to approximately 1.9 x 10{sup -3} M{Omega} cm{sup 2} and 4.2 x 10{sup -3} M{Omega} cm{sup 2}, respectively, after ageing in air. This was attributed to the presence of compressive stresses at the specimen surface after LSP treatment. Stress values were determined from XRD measurements.

  3. Micro/nanoscale continuous printing: direct-writing of wavy micro/nano structures via electrospinning

    Science.gov (United States)

    Fang, Feiyu; Du, Zefeng; Zeng, Jun; Zhu, Ziming; Chen, Xin; Chen, Xindu; Lv, Yuanjun; Wang, Han

    2015-07-01

    Micro/nanofibers that are created by direct-writing using an electrospinning (ES) technique have aroused much recent attention, owing to their intriguing physical properties and great potential as building blocks for micro/nanoscale devices. In this work, a wavy direct-writing (WDW) process was developed to directly write wavy micro/nanostructures suitable for the fabrication of micro/nanoscale devices. The low voltage WDW technique is anticipated to be useful for a broad range of applications including flexible/stretchable electronics, micro optoelectronics, nano-antennas, microelectromechanical systems (MEMS), and biomedical engineering.

  4. Micro injection moulding process validation for high precision manufacture of thermoplastic elastomer micro suspension rings

    DEFF Research Database (Denmark)

    Calaon, M.; Tosello, G.; Elsborg Hansen, R.

    Micro injection moulding (μIM) is one of the most suitable micro manufacturing processes for flexible mass-production of multi-material functional micro components. The technology was employed in this research used to produce thermoplastic elastomer (TPE) micro suspension rings identified...... as critical component in micro acoustic applications (e.g. phono cartridges, see Figure 1a). The suspension ring holds in place the preassembled aluminium cantilever, magnet and diamond tip seen (see Figure 1b and 1c). The specific damping properties of the TPE material reduces vibrations differently depended...

  5. Flexible MEMS: A novel technology to fabricate flexible sensors and electronics

    Science.gov (United States)

    Tu, Hongen

    This dissertation presents the design and fabrication techniques used to fabricate flexible MEMS (Micro Electro Mechanical Systems) devices. MEMS devices and CMOS(Complementary Metal-Oxide-Semiconductor) circuits are traditionally fabricated on rigid substrates with inorganic semiconductor materials such as Silicon. However, it is highly desirable that functional elements like sensors, actuators or micro fluidic components to be fabricated on flexible substrates for a wide variety of applications. Due to the fact that flexible substrate is temperature sensitive, typically only low temperature materials, such as polymers, metals, and organic semiconductor materials, can be directly fabricated on flexible substrates. A novel technology based on XeF2(xenon difluoride) isotropic silicon etching and parylene conformal coating, which is able to monolithically incorporate high temperature materials and fluidic channels, was developed at Wayne State University. The technology was first implemented in the development of out-of-plane parylene microneedle arrays that can be individually addressed by integrated flexible micro-channels. These devices enable the delivery of chemicals with controlled temporal and spatial patterns and allow us to study neurotransmitter-based retinal prosthesis. The technology was further explored by adopting the conventional SOI-CMOS processes. High performance and high density CMOS circuits can be first fabricated on SOI wafers, and then be integrated into flexible substrates. Flexible p-channel MOSFETs (Metal-Oxide-Semiconductor Field-Effect-Transistors) were successfully integrated and tested. Integration of pressure sensors and flow sensors based on single crystal silicon has also been demonstrated. A novel smart yarn technology that enables the invisible integration of sensors and electronics into fabrics has been developed. The most significant advantage of this technology is its post-MEMS and post-CMOS compatibility. Various high

  6. Biologically Inspired Micro-Flight Research

    Science.gov (United States)

    Raney, David L.; Waszak, Martin R.

    2003-01-01

    Natural fliers demonstrate a diverse array of flight capabilities, many of which are poorly understood. NASA has established a research project to explore and exploit flight technologies inspired by biological systems. One part of this project focuses on dynamic modeling and control of micro aerial vehicles that incorporate flexible wing structures inspired by natural fliers such as insects, hummingbirds and bats. With a vast number of potential civil and military applications, micro aerial vehicles represent an emerging sector of the aerospace market. This paper describes an ongoing research activity in which mechanization and control concepts for biologically inspired micro aerial vehicles are being explored. Research activities focusing on a flexible fixed- wing micro aerial vehicle design and a flapping-based micro aerial vehicle concept are presented.

  7. Structural dynamics and aerodynamics measurements of biologically inspired flexible flapping wings

    Energy Technology Data Exchange (ETDEWEB)

    Wu, P; Stanford, B K; Ifju, P G [Department of Mechanical and Aerospace Engineering, MAE-A 231, University of Florida, Gainesville, FL 32611 (United States); Saellstroem, E; Ukeiley, L, E-mail: diccidwp@ufl.edu [Department of Mechanical and Aerospace Engineering, University of Florida, Shalimar, FL 32579 (United States)

    2011-03-15

    Flapping wing flight as seen in hummingbirds and insects poses an interesting unsteady aerodynamic problem: coupling of wing kinematics, structural dynamics and aerodynamics. There have been numerous studies on the kinematics and aerodynamics in both experimental and computational cases with both natural and artificial wings. These studies tend to ignore wing flexibility; however, observation in nature affirms that passive wing deformation is predominant and may be crucial to the aerodynamic performance. This paper presents a multidisciplinary experimental endeavor in correlating a flapping micro air vehicle wing's aeroelasticity and thrust production, by quantifying and comparing overall thrust, structural deformation and airflow of six pairs of hummingbird-shaped membrane wings of different properties. The results show that for a specific spatial distribution of flexibility, there is an effective frequency range in thrust production. The wing deformation at the thrust-productive frequencies indicates the importance of flexibility: both bending and twisting motion can interact with aerodynamic loads to enhance wing performance under certain conditions, such as the deformation phase and amplitude. By measuring structural deformations under the same aerodynamic conditions, beneficial effects of passive wing deformation can be observed from the visualized airflow and averaged thrust. The measurements and their presentation enable observation and understanding of the required structural properties for a thrust effective flapping wing. The intended passive responses of the different wings follow a particular pattern in correlation to their aerodynamic performance. Consequently, both the experimental technique and data analysis method can lead to further studies to determine the design principles for micro air vehicle flapping wings.

  8. Suprathermal electron energy spectrum and nonlocally affected plasma-wall interaction in helium/air micro-plasma at atmospheric pressure

    Science.gov (United States)

    Demidov, V. I.; Adams, S. F.; Miles, J. A.; Koepke, M. E.; Kurlyandskaya, I. P.

    2016-10-01

    Details of ground-state and excited-state neutral atoms and molecules in an atmospheric-pressure micro-discharge plasma may be obtained by plasma electron spectroscopy (PLES), based on a wall probe. The presence and transport of energetic (suprathermal) electrons, having a nonlocal origin, are responsible for electrostatic charging of the plasma boundary surfaces to potentials many times that associated with the ambient electron kinetic energy. The energy-flux distribution function is shown to be controllable for applications involving analysis of composition and processes taking place in a multiphase (plasma-gas-solid), chemically reactive, interaction region.

  9. 过渡型艇微气泡减阻喷缝尺度影响数值计算%Numerical Calculation on the Influence of the Slot Size of Air Injection on Micro Bubbles Drag Reduction for Transitional Craft

    Institute of Scientific and Technical Information of China (English)

    王家楣; 张玲

    2011-01-01

    针对一优良过渡型艇,为喷气需要进行船底断阶,采用有限体积法、SIMPLEC算法和k-ε两方程湍流模型,不计自由面影响,计及气泡与水的相对运动,数值求解包含气液两相流的雷诺平均控制方程组.获得不同喷缝宽度、不同傅汝德数和相对喷气速度下的船舶的阻力特性和气泡浓度分布规律并与模型实验结果进行对比分析.结果显示:在获得高减阻率条件下,Cn随Fr增加而呈非线性增加,当Fr=0.779时,Cn达到最大值;在获得25%减阻率的条件下,Fr=0.973时相对喷缝宽度为0.112所需喷气量最小即喷气所消耗功率最小.计算结果可为高速气泡船喷缝参数设计提供参考.%The two-phase flow around a fine transitional with step for injecting air is figured out numerically under the condition of neglecting influences of free-surface. The drag characteristic of the ship and the distribution of the volume fraction of micro bubble are got at different air jet slot size,Fr and relative air injection velocity. The results show that at Cn=25% and Fr=0.973, the air flow rate could reach minimum if non-dimension jet slot size is 0.112. The calculation result will provide reference on the parametric design of air injection slot of High-Speed Air Cavity Craft.

  10. Flow field of flexible flapping wings

    Science.gov (United States)

    Sallstrom, Erik

    The agility and maneuverability of natural fliers would be desirable to incorporate into engineered micro air vehicles (MAVs). However, there is still much for engineers to learn about flapping flight in order to understand how such vehicles can be built for efficient flying. The goal of this study is to develop a methodology for capturing high quality flow field data around flexible flapping wings in a hover environment and to interpret it to gain a better understanding of how aerodynamic forces are generated. The flow field data was captured using particle image velocimetry (PIV) and required that measurements be taken around a repeatable flapping motion to obtain phase-averaged data that could be studied throughout the flapping cycle. Therefore, the study includes the development of flapping devices with a simple repeatable single degree of freedom flapping motion. The acquired flow field data has been examined qualitatively and quantitatively to investigate the mechanisms behind force production in hovering flight and to relate it to observations in previous research. Specifically, the flow fields have been investigated around a rigid wing and several carbon fiber reinforced flexible membrane wings. Throughout the whole study the wings were actuated with either a sinusoidal or a semi-linear flapping motion. The semi-linear flapping motion holds the commanded angular velocity nearly constant through half of each half-stroke while the sinusoidal motion is always either accelerating or decelerating. The flow fields were investigated by examining vorticity and vortex structures, using the Q criterion as the definition for the latter, in two and three dimensions. The measurements were combined with wing deflection measurements to demonstrate some of the key links in how the fluid-structure interactions generated aerodynamic forces. The flow fields were also used to calculate the forces generated by the flapping wings using momentum balance methods which yielded

  11. Flexible Thermoelectric Generators on Silicon Fabric

    KAUST Repository

    Sevilla, Galo T.

    2012-11-01

    In this work, the development of a Thermoelectric Generator on Flexible Silicon Fabric is explored to extend silicon electronics for flexible platforms. Low cost, easily deployable plastic based flexible electronics are of great interest for smart textile, wearable electronics and many other exciting applications. However, low thermal budget processing and fundamentally limited electron mobility hinders its potential to be competitive with well established and highly developed silicon technology. The use of silicon in flexible electronics involve expensive and abrasive materials and processes. In this work, high performance flexible thermoelectric energy harvesters are demonstrated from low cost bulk silicon (100) wafers. The fabrication of the micro- harvesters was done using existing silicon processes on silicon (100) and then peeled them off from the original substrate leaving it for reuse. Peeled off silicon has 3.6% thickness of bulk silicon reducing the thermal loss significantly and generating nearly 30% more output power than unpeeled harvesters. The demonstrated generic batch processing shows a pragmatic way of peeling off a whole silicon circuitry after conventional fabrication on bulk silicon wafers for extremely deformable high performance integrated electronics. In summary, by using a novel, low cost process, this work has successfully integrated existing and highly developed fabrication techniques to introduce a flexible energy harvester for sustainable applications.

  12. Design and fabrication of self-powered micro-harvesters rotating and vibrated micro-power systems

    CERN Document Server

    Pan, C T; Lin, Liwei; Chen, Ying-Chung

    2013-01-01

    Presents the latest methods for designing and fabricating self-powered micro-generators and energy harvester systems Design and Fabrication of Self-Powered Micro-Harvesters introduces the latest trends of self-powered generators and energy harvester systems, including the design, analysis and fabrication of micro power systems. Presented in four distinct parts, the authors explore the design and fabrication of: vibration-induced electromagnetic micro-generators; rotary electromagnetic micro-generators; flexible piezo-micro-generator with various widths; and PVDF electrospunpiezo-energy with

  13. Flexible energy-storage devices: design consideration and recent progress.

    Science.gov (United States)

    Wang, Xianfu; Lu, Xihong; Liu, Bin; Chen, Di; Tong, Yexiang; Shen, Guozhen

    2014-07-23

    Flexible energy-storage devices are attracting increasing attention as they show unique promising advantages, such as flexibility, shape diversity, light weight, and so on; these properties enable applications in portable, flexible, and even wearable electronic devices, including soft electronic products, roll-up displays, and wearable devices. Consequently, considerable effort has been made in recent years to fulfill the requirements of future flexible energy-storage devices, and much progress has been witnessed. This review describes the most recent advances in flexible energy-storage devices, including flexible lithium-ion batteries and flexible supercapacitors. The latest successful examples in flexible lithium-ion batteries and their technological innovations and challenges are reviewed first. This is followed by a detailed overview of the recent progress in flexible supercapacitors based on carbon materials and a number of composites and flexible micro-supercapacitors. Some of the latest achievements regarding interesting integrated energy-storage systems are also reviewed. Further research direction is also proposed to surpass existing technological bottle-necks and realize idealized flexible energy-storage devices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Micro Manufacturing

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard

    2003-01-01

    . If a micro manufacturing system isn’t designed rationally and correctly, it will be high-cost, unreliable, and not robust. For micro products and systems it is a continuously increasing challenge to create the operational basis for an industrial production. As the products through product development...... processes are made applicable to a large number of customers, the pressure in regard to developing production technologies that make it possible to produce the products at a reasonable price and in large numbers is growing. The micro/nano manufacturing programme at the Department of Manufacturing...

  15. HIGH IMPEDANCE SURFACES FOR FLEXIBLE AND CONFORMAL WIRELESS SYSTEMS

    Directory of Open Access Journals (Sweden)

    Haider R. Khaleel

    2014-01-01

    Full Text Available Recent years have witnessed a great deal of interest from both scientific and academic communities in the field of flexible electronic systems. Most flexible electronic systems require the integration of flexible antennas operating in specific frequency bands to provide wireless connectivity which is highly demanded by today’s network oriented society. On the other hand, High Impedance Surfaces have become very popular in the design of contemporary antenna and micro-wave devices due to their wide range of applications derived from their unique electromagnetic properties which significantly enhance the performance of antennas and RF systems. Accordingly, the integration of HIS structures within flexible wireless systems is very beneficial in this growing field of research. In this paper, a systematic review of flexible HIS structures reported in the literature is conducted, which provides the reader with a thorough description and a complete list of state of the art designs intended for flexible wireless systems.

  16. 75 FR 59711 - Audit Program for Texas Flexible Permit Holders

    Science.gov (United States)

    2010-09-28

    ... waiver of the gravity component of any penalties resulting from noncompliance uncovered by the Audit... on the Audit Program for Texas flexible permit holders, please contact Mr. John Jones, Air...). EPA is proposing the Audit Program as a mechanism for Texas Flexible Permit holders to transition...

  17. Application of Ultra-Small Micro Grinding and Micro Milling Tools: Possibilities and Limitations

    Directory of Open Access Journals (Sweden)

    Benjamin Kirsch

    2017-08-01

    Full Text Available Current demands for flexible, individual microstructures in high quality result in high requirements for micro tools. As the tool size defines the minimum structure size, ultra-small tools are needed. To achieve tool diameters of 50 µm and lower, we investigate the complete manufacturing chain of micro machining. From the development of the machine tools and components needed to produce and apply the micro tools, the micro tools themselves, as well as the micro machining processes. Machine tools are developed with the possibility of producing the micro geometry (cutting edge design of micro tools as well as plating processes to produce super abrasive micro grinding tools. Applying these setups, we are able to produce ultra-small micro grinding and micro milling tools with typical diameters of 50 µm and down to 4 µm. However, the application of such tools is very challenging. The article presents possibilities and limitations in manufacturing the micro tools themselves as well as microstructures made with these tools. A special emphasis will be on the influence of the tool substrate in micro milling and grain sizes in micro grinding.

  18. Experimental investigations of active air bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar; Morosi, Stefano

    2012-01-01

    Along with traditional oil lubrication, increasing demand for high-speed applications has renewed attention to gas bearings technology. Traditional aerostatic and aerodynamic gas lubrication has been widely used in a variety of applications, ranging from high-speed spindles to micro and meso......-scale turbomachinery. The present paper deals with experimental rotordynamic testing of a flexible rotor supported by hybrid aerostaticaerodynamic gas journal bearing equipped with an electronic radial air injection system. From a rotordynamic point of view there are two phenomena that limit the widespread...... of traditional gas lubrication: 1) Low damping makes operation across critical speed dangerous, as even low level of unbalance can generate large vibration responses. This is especially problematic for gas bearing applications, which often operate in the supercritical region. Moreover, 2) An upper bound...

  19. Ferrocene pixels by laser-induced forward transfer: towards flexible microelectrode printing

    Science.gov (United States)

    Mitu, B.; Matei, A.; Filipescu, M.; Palla Papavlu, A.; Bercea, A.; Lippert, T.; Dinescu, M.

    2017-03-01

    The aim of this work is to demonstrate the potential of laser-induced forward transfer (LIFT) as a printing technology, alternative to standard microfabrication techniques, in the area of flexible micro-electrode fabrication. First, ferrocene thin films are deposited onto fused silica and fused silica substrates previously coated with a photodegradable polymer film (triazene polymer) by matrix assisted pulsed laser evaporation (MAPLE). The morphology and chemical structure of the ferrocene thin films deposited by MAPLE has been investigated by atomic force microscopy and Fourier transformed infrared spectroscopy, and no structural damage occurs as a result of the laser deposition. Second, LIFT is applied to print for the first time ferrocene pixels and lines onto flexible polydimethylsiloxane (PDMS) substrates. The ferrocene pixels and lines are flawlessly transferred onto the PDMS substrates in air at room temperature, without the need of additional conventional photolithography processes. We believe that these results are very promising for a variety of applications ranging from flexible electronics to lab-on-a-chip devices, MEMS, and medical implants.

  20. Adhesion Transition of Flexible Filaments

    Science.gov (United States)

    Evans, Arthur; Lauga, Eric

    2009-03-01

    As forays into fabrication and self-assembly venture to increasingly small length scales, the role of adhesion events between material elements of the system must be closely scrutinized. This area of study is typically dominated by investigations into capillary adhesion, but relatively recent interest in carbon nanotubes and biomimetic devices have spurred interest in intermolecular forces as another source of micro- and nano-scale adhesion. We present here a far-field model for ``dry'' adhesion. We consider a small number N of flexible beams interacting with each other via a typical Lennard-Jones 6-12 potential, and describe the behavior of the system as the ratio of bending rigidity to beam-beam attraction is reduced. Applications ranging from fibrillar systems to the comparatively stiff carbon nanotubes are discussed.

  1. The Characterization of Material Properties and Structural Dynamics of the Manduca Sexta Forewing for Application to Flapping Wing Micro Air Vehicle Design

    Science.gov (United States)

    O'Hara, Ryan P.

    Collateral damage presents a significant risk during air drops and airstrikes, risking citizens' lives and property, straining the relationship between the United States Air Force and host nations. This dissertation presents a methodology to determine the optimal location for making supply airdrops in order to minimize collateral damage while maintaining a high likelihood of successful recovery. A series of non-linear optimization algorithms are presented along with their relative success in finding the optimal location in the airdrop problem. Additionally, we present a quick algorithm for accurately creating the Pareto frontier in the multi-objective airstrike problem. We demonstrate the effect of differing guidelines, damage functions, and weapon employment selection which significantly alter the location of the optimal aimpoint in this targeting problem. Finally, we have provided a framework for making policy decisions in fast-moving troops-in-contact situations where observers are unsure of the nature of possible enemy forces in both finite and infinite time horizon problems. Through a recursive technique of solving this Markov decision process we have demonstrated the effect of improved intelligence and differing weights in the face of uncertain situations.

  2. Capturing the sensitivity of land-use regression models to short-term mobile monitoring campaigns using air pollution micro-sensors.

    Science.gov (United States)

    Minet, L; Gehr, R; Hatzopoulou, M

    2017-11-01

    The development of reliable measures of exposure to traffic-related air pollution is crucial for the evaluation of the health effects of transportation. Land-use regression (LUR) techniques have been widely used for the development of exposure surfaces, however these surfaces are often highly sensitive to the data collected. With the rise of inexpensive air pollution sensors paired with GPS devices, we witness the emergence of mobile data collection protocols. For the same urban area, can we achieve a 'universal' model irrespective of the number of locations and sampling visits? Can we trade the temporal representation of fixed-point sampling for a larger spatial extent afforded by mobile monitoring? This study highlights the challenges of short-term mobile sampling campaigns in terms of the resulting exposure surfaces. A mobile monitoring campaign was conducted in 2015 in Montreal; nitrogen dioxide (NO2) levels at 1395 road segments were measured under repeated visits. We developed LUR models based on sub-segments, categorized in terms of the number of visits per road segment. We observe that LUR models were highly sensitive to the number of road segments and to the number of visits per road segment. The associated exposure surfaces were also highly dissimilar. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Utilisation de la post-décharge d'un plasma micro-ondes d'air ou d'azote pour valoriser le méthane

    Science.gov (United States)

    Oumghar, A.; Legrand, J. C.; Diamy, A. M.; Turillon, N.; Ben-Aïm, R. I.

    1994-01-01

    Valorization of methane is obtained by means of the reaction with a plasma. The plasma is produced in a quartz tube (30 mm in diameter) crossing a wave guide. The energy is supplied by a generator (Thomson CSF, 2 450 MHz, 15 to 1 500 W). Directional couplers followed by an attenuator and thermistor detectors enable forward Pi_i and reflected Pi_r power to be measured. Methane is introduced in the post-discharge zone through five tubes symmetrically arranged around the reactor. Methane consumption α, selectivity SX and yield RX are measured as a function of the following parameters : β methane/air ratio, F gaz flow, d distance where methane is introduced in the plasma, P pressure, Pi microwave power absorbed by air or nitrogen. It appears that acetylene is the major hydrocarbon obtained. The corresponding selectivity is increased when Pi and P are increased or when d and F are decreased. The optimum value of β is 4/5. If the best experimental conditions are selected, selectivity of total C2 reaches 44 % with a conversion ratio of 80 %. By decreasing methane/air ratio, carbon monoxide yield is increased. The ratio acetylene/ethylene can by varied without changing the conversion ratio, by introducing a catalyst in the post reaction zone. La valorisation du méthane est réalisée dans la post-décharge d'un plasma microondes (2 450 MHz) d'air ou d'azote. Lorsque la décharge est produite dans l'azote, les principaux produits dosés sont l'acétylène, l'éthylène, l'éthane et l'hydrogène. Lorsque la décharge est produite dans l'air, on dose en outre le monoxyde de carbone. Le taux de conversion du méthane ainsi que la sélectivité des produits ont été déterminés en fonction des paramètres expérimentaux suivants : proportion méthane/gaz plasmagène, flux gazeux, distance d'introduction du méthane dans la post-décharge, pression et puissance micro-ondes. Le procédé expérimenté permet d'obtenir des rendements chimiques importants et d'éviter la

  4. Invertible flexible matrices

    Science.gov (United States)

    Justino, Júlia

    2017-06-01

    Matrices with coefficients having uncertainties of type o (.) or O (.), called flexible matrices, are studied from the point of view of nonstandard analysis. The uncertainties of the afore-mentioned kind will be given in the form of the so-called neutrices, for instance the set of all infinitesimals. Since flexible matrices have uncertainties in their coefficients, it is not possible to define the identity matrix in an unique way and so the notion of spectral identity matrix arises. Not all nonsingular flexible matrices can be turned into a spectral identity matrix using Gauss-Jordan elimination method, implying that that not all nonsingular flexible matrices have the inverse matrix. Under certain conditions upon the size of the uncertainties appearing in a nonsingular flexible matrix, a general theorem concerning the boundaries of its minors is presented which guarantees the existence of the inverse matrix of a nonsingular flexible matrix.

  5. Global Sourcing Flexibility

    DEFF Research Database (Denmark)

    Ørberg Jensen, Peter D.; Petersen, Bent

    2013-01-01

    sourcing flexibility. Here we draw on prior research in the fields of organizational flexibility, international business and global sourcing as well as case examples and secondary studies. In the second part of the paper, we discuss the implications of global sourcing flexibility for firm strategy......Recent studies show that flexibility is a key concern for firms that engage in the global sourcing of services. In this conceptual paper, we seek to explore two central aspects of global sourcing flexibility: In the first part of the paper, we provide a definition of the construct of global...... and operations against the backdrop of the theory-based definition of the construct. We discuss in particular the importance of global sourcing flexibility for operational performance stability, and the trade-off between specialization benefits, emerging from location and service provider specialization, versus...

  6. Call centres: constructing flexibility

    OpenAIRE

    Arzbächer, Sandra; Holtgrewe, Ursula; Kerst, Christian

    2002-01-01

    "The development of call centres as a flexible interface between firms and their environments has been seen as exemplary or even symptomatic of flexible capitalism (Sennett 1998). We are going to point out that they do not just stand for organisational change but also for changes of institutions towards deregulation. Employers and managers hoped for gains of flexibility, decreasing labour costs, and market gains by an expanded 24-hour-service. Surveillance and control by flexib...

  7. Pneumatic flexible shaft couplings

    OpenAIRE

    2007-01-01

    Main effort of every design engineer is reduction of torsional oscillation in any mechanical system. At present this problem can be solved by means of a suitable modification of dynamic properties of flexible shaft couplings according to dynamics in the given systems. But the dynamic properties of nowadays-applied flexible couplings arenot unchangeable because of aging and fatigue processes occurring in flexible coupling elements. Result of this fact causes detuning of mechanical system. Taki...

  8. Adaptability Research on Micro-channel Heat Exchanger Applied to Heat Pump Air Conditioning System for Electrical Vehicle%电动汽车热泵空调系统微通道换热器适应性研究

    Institute of Scientific and Technical Information of China (English)

    巫江虹; 谢方; 刘超鹏; 欧阳光

    2012-01-01

    One enhanced and baseline heat pump air conditioning system(HPACS) for electrical vehicle(EV) are established including the new multi-flow micro-channel heat exchangers(HE) and the traditional fin-and-tube heat exchangers(HE), respectively. Is order to provide theoretical guidance to the follow-up research of EV HPACS based on novel micro-channel design and frosting control, the performance differences are discussed between the two systems, the refrigeration and heating characteristics of both systems are compared under variable test conditions and the results show that volume of the indoor and outdoor heat exchangers decrease by 57.6% and 62.5%, respectively, effectively reduce air conditioner's weight which contributes to the increase of EV's Life mileage; at the same time, the enhanced system with compact HE could reduce air conditioner system's charge by 26.5% which benefits to reduce the greenhouse effect The cooling capacity and refrigeration coefficient of performance of the enhanced system reduce by 4.1%-10.7% and 1.7%-4.8%, respectively. It indicates that there are still some technical barriers require to be managed in case of multi-flow micro-channel HE applied in HPACS, for example, the flow path design of micro-channel HE, flow distribution and pressure drop in micro-channel HE. The heating capacity and heating performance coefficient of the enhanced system reduce by l%-5% and 4.2%-9.7%, but the heating capacity per unit area increase by 16.7%-21.0%. The outdoor micro-channel HE will be frost when the outdoor temperature below 7 ℃, it immensely affects the heating capacity and the heating performance coefficient of enhanced system and demands to improve the frosting control strategy.%探讨管翅式换热器和多流程微通道换热器在同一电动汽车热泵空调系统中的性能差异,为电动汽车热泵空调系统中微通道设计和结霜控制的后续研究提供依据.试验比较在不同测试工况下采用微通道换热器和

  9. Understanding Micro Plasmas

    CERN Document Server

    Winter, J; Böke, M; Ellerweg, D; Hemke, T; Knake, N; Mussenbrock, T; Niermann, B; Schröder, D; der Gathen, V Schulz-von; von Keudell, A

    2011-01-01

    Micro plasmas are operated around atmospheric pressure exhibiting pronounced non-equilibrium characteristics, i.e. they possess energetic electrons while ions and neutrals remain cold. They have gained significant interest due to their enormous application potential e.g. in the biomedical, surface modification and light source areas, just to name a few. Many different configurations are in use. Their understanding and quantification is mandatory for further progress in applications. We report on recent progress in the diagnostics and simulation of the entire micro plasma system from gas introduction, via the plasma discharge up to the samples at the example of a plasma jet operated in He/O2 in an ambient air environment.

  10. SILICON NEEDLE ARRAY ON FLEXIBLE SUBSTRATE FOR FLUID TRANSFER

    Institute of Scientific and Technical Information of China (English)

    MA Bin; GAN Zhiyin; LIU Sheng

    2006-01-01

    Transdermal delivery is an attractive alternative, but it is limited by the extremely low permeability of skin. To solve this problem, a novel means-micro needle array based on micro electro-mechanical system (MEMS) technology, is provided to increase permeability of human skin with efficiency, safety and painless delivery. The fabrication method consists of a sequence of deep-reactive ion etching (DRIE), anisotropic wet etching and conformal thin film deposition. The novel technology can enable the realization of micro fabricated micro needle array on a flexible silicon substrate. The micro needle array can be mounted on non-planar surface or even on flexible objects such as a human fingers and arms. The fabricated hollow wall straight micro needles are 200 μm in length, 30 μm inner diameter, and 50 μm outer diameter with 250 μm center-to-center spacing.Flow rate test proves that the polymeric base construction is important to function of micro needles array in package. Glucose solvent tests show that surface tension is the dominant force to affect the characters of flow in micro needles channel.

  11. Flexible and Lightweight Fuel Cell with High Specific Power Density.

    Science.gov (United States)

    Ning, Fandi; He, Xudong; Shen, Yangbin; Jin, Hehua; Li, Qingwen; Li, Da; Li, Shuping; Zhan, Yulu; Du, Ying; Jiang, Jingjing; Yang, Hui; Zhou, Xiaochun

    2017-06-27

    Flexible devices have been attracting great attention recently due to their numerous advantages. But the energy densities of current energy sources are still not high enough to support flexible devices for a satisfactory length of time. Although proton exchange membrane fuel cells (PEMFCs) do have a high-energy density, traditional PEMFCs are usually too heavy, rigid, and bulky to be used in flexible devices. In this research, we successfully invented a light and flexible air-breathing PEMFC by using a new design of PEMFC and a flexible composite electrode. The flexible air-breathing PEMFC with 1 × 1 cm(2) working area can be as light as 0.065 g and as thin as 0.22 mm. This new PEMFC exhibits an amazing specific volume power density as high as 5190 W L(-1), which is much higher than traditional (air-breathing) PEMFCs. Also outstanding is that the flexible PEMFC retains 89.1% of its original performance after being bent 600 times, and it retains its original performance after being dropped five times from a height of 30 m. Moreover, the research has demonstrated that when stacked, the flexible PEMFCs are also useful in mobile applications such as mobile phones. Therefore, our research shows that PEMFCs can be made light, flexible, and suitable for applications in flexible devices. These innovative flexible PEMFCs may also notably advance the progress in the PEMFC field, because flexible PEMFCs can achieve high specific power density with small size, small volume, low weight, and much lower cost; they are also much easier to mass produce.

  12. Micro Manufacturing

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard

    2003-01-01

    Manufacturing deals with systems that include products, processes, materials and production systems. These systems have functional requirements, constraints, design parameters and process variables. They must be decomposed in a systematic manner to achieve the best possible system performance....... If a micro manufacturing system isn’t designed rationally and correctly, it will be high-cost, unreliable, and not robust. For micro products and systems it is a continuously increasing challenge to create the operational basis for an industrial production. As the products through product development...... processes are made applicable to a large number of customers, the pressure in regard to developing production technologies that make it possible to produce the products at a reasonable price and in large numbers is growing. The micro/nano manufacturing programme at the Department of Manufacturing...

  13. Transplantation and Appl ication of MAVLink Micro Unmanned Air Vehicle Communication Protocol Based on DSP%DSP 的 MAVLink 微型无人机通信协议移植与应用

    Institute of Scientific and Technical Information of China (English)

    吕强; 倪佩佩; 王国胜; 刘峰

    2014-01-01

    MAVLink micro unmanned air vehicle communication protocol is widely used in communications between the ground control station and unmanned air vehicle flight control platform such as PIXHAWK,SLUGS and ArduPilot.MAVLink has been proven to work on ARM7,ATmega and STM32 microcontrollers and it can be developed under Windows,Linux and MacOS operating systems. Because of MAVLink'incompatibility with DSP,a method is proposed to transplant MAVLink to DSP and communicate with ground control station software QGroundControl via WiFi.Experimental results show that this method can effectively make MAVLink compati-ble with DSP,reduce CPU consumption via SPI-to-WiFi,improve data transmission rates and reduce data loss.%MAVLink 微型无人机通信协议广泛应用于地面控制站与 PIXHAWK、SLUGS 和 ArduPilot 等无人机飞控平台的通信。MAVLink 已被证明能够工作在 ARM7、ATmega、STM32等微控制器上,并能在 Windows、Linux 和 MacOS 操作系统下开发。由于 MAVLink 与 DSP 不兼容,故本文提出一种将 MAVLink 移植到 DSP,并通过 WiFi 与地面控制站软件 QGroundControl 进行通信的方法。实验证明,该方法能够使 MAVLink 有效兼容 DSP,并且通过 SPI 转 WiFi 连接,减小了 CPU 开销,提高了数据传输速率,减少了数据的丢失情况。

  14. Reversibly Bistable Flexible Electronics

    KAUST Repository

    Alfaraj, Nasir

    2015-05-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent. While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin and foldable ones without compromising long-term performance and reliability. In this work, we report on the fabrication and characterization of reversibly bistable flexible electronic switches that utilize flexible n-channel metal-oxide-semiconductor field-effect transistors. The transistors are fabricated initially on rigid (100) silicon substrates before they are peeled off. They can be used to control flexible batches of light-emitting diodes, demonstrating both the relative ease of scaling at minimum cost and maximum reliability and the feasibility of integration. The peeled-off silicon fabric is about 25 µm thick. The fabricated devices are transferred to a reversibly bistable flexible platform through which, for example, a flexible smartphone can be wrapped around a user’s wrist and can also be set back to its original mechanical position. Buckling and cyclic bending of such host platforms brings a completely new dimension to the development of flexible electronics, especially rollable displays.

  15. Organizational flexibility estimation

    OpenAIRE

    Komarynets, Sofia

    2013-01-01

    By the help of parametric estimation the evaluation scale of organizational flexibility and its parameters was formed. Definite degrees of organizational flexibility and its parameters for the Lviv region enterprises were determined. Grouping of the enterprises under the existing scale was carried out. Special recommendations to correct the enterprises behaviour were given.

  16. Flexible magnetoimpidence sensor

    KAUST Repository

    Kavaldzhiev, Mincho

    2015-05-01

    Recently, flexible electronic devices have attracted increasing interest, due to the opportunities they promise for new applications such as wearable devices, where the components are required to flex during normal use[1]. In this light, different magnetic sensors, like microcoil, spin valve, giant magnetoresistance (GMR), magnetoimpedance (MI), have been studied previously on flexible substrates.

  17. Flexible 'zoning' aids adaptability.

    Science.gov (United States)

    Corben, Simon

    2013-09-01

    Simon Corben, business development director at Capita Symonds' Health team, examines how 'clever use of zoning' when planning new healthcare facilities could improve hospital design, increase inherent flexibility, and reduce lifetime costs, and argues that a 'loose-fit, non-bespoke approach' to space planning will lead to 'more flexible buildings that are suitable for conversion to alternative uses'.

  18. Dual-energy micro-CT imaging of pulmonary airway obstruction: correlation with micro-SPECT

    Science.gov (United States)

    Badea, C. T.; Befera, N.; Clark, D.; Qi, Y.; Johnson, G. A.

    2014-03-01

    To match recent clinical dual energy (DE) CT studies focusing on the lung, similar developments for DE micro-CT of the rodent lung are required. Our group has been actively engaged in designing pulmonary gating techniques for micro- CT, and has also introduced the first DE micro-CT imaging method of the rodent lung. The aim of this study was to assess the feasibility of DE micro-CT imaging for the evaluation of airway obstruction in mice, and to compare the method with micro single photon emission computed tomography (micro-SPECT) using technetium-99m labeled macroaggregated albumin (99mTc-MAA). The results suggest that the induced pulmonary airway obstruction causes either atelectasis, or air-trapping similar to asthma or chronic bronchitis. Atelectasis could only be detected at early time points in DE micro-CT images, and is associated with a large increase in blood fraction and decrease in air fraction. Air trapping had an opposite effect with larger air fraction and decreased blood fraction shown by DE micro-CT. The decrease in perfusion to the hypoventilated lung (hypoxic vasoconstriction) is also seen in micro-SPECT. The proposed DE micro-CT technique for imaging localized airway obstruction performed well in our evaluation, and provides a higher resolution compared to micro-SPECT. Both DE micro-CT and micro-SPECT provide critical, quantitative lung biomarkers for image-based anatomical and functional information in the small animal. The methods are readily linked to clinical methods allowing direct comparison of preclinical and clinical results.

  19. Flexible ferroelectric organic crystals

    Science.gov (United States)

    Owczarek, Magdalena; Hujsak, Karl A.; Ferris, Daniel P.; Prokofjevs, Aleksandrs; Majerz, Irena; Szklarz, Przemysław; Zhang, Huacheng; Sarjeant, Amy A.; Stern, Charlotte L.; Jakubas, Ryszard; Hong, Seungbum; Dravid, Vinayak P.; Stoddart, J. Fraser

    2016-10-01

    Flexible organic materials possessing useful electrical properties, such as ferroelectricity, are of crucial importance in the engineering of electronic devices. Up until now, however, only ferroelectric polymers have intrinsically met this flexibility requirement, leaving small-molecule organic ferroelectrics with room for improvement. Since both flexibility and ferroelectricity are rare properties on their own, combining them in one crystalline organic material is challenging. Herein, we report that trisubstituted haloimidazoles not only display ferroelectricity and piezoelectricity--the properties that originate from their non-centrosymmetric crystal lattice--but also lend their crystalline mechanical properties to fine-tuning in a controllable manner by disrupting the weak halogen bonds between the molecules. This element of control makes it possible to deliver another unique and highly desirable property, namely crystal flexibility. Moreover, the electrical properties are maintained in the flexible crystals.

  20. Flexible ferroelectric organic crystals

    Science.gov (United States)

    Owczarek, Magdalena; Hujsak, Karl A.; Ferris, Daniel P.; Prokofjevs, Aleksandrs; Majerz, Irena; Szklarz, Przemysław; Zhang, Huacheng; Sarjeant, Amy A.; Stern, Charlotte L.; Jakubas, Ryszard; Hong, Seungbum; Dravid, Vinayak P.; Stoddart, J. Fraser

    2016-01-01

    Flexible organic materials possessing useful electrical properties, such as ferroelectricity, are of crucial importance in the engineering of electronic devices. Up until now, however, only ferroelectric polymers have intrinsically met this flexibility requirement, leaving small-molecule organic ferroelectrics with room for improvement. Since both flexibility and ferroelectricity are rare properties on their own, combining them in one crystalline organic material is challenging. Herein, we report that trisubstituted haloimidazoles not only display ferroelectricity and piezoelectricity—the properties that originate from their non-centrosymmetric crystal lattice—but also lend their crystalline mechanical properties to fine-tuning in a controllable manner by disrupting the weak halogen bonds between the molecules. This element of control makes it possible to deliver another unique and highly desirable property, namely crystal flexibility. Moreover, the electrical properties are maintained in the flexible crystals. PMID:27734829

  1. Flexible Carbon Aerogels

    Directory of Open Access Journals (Sweden)

    Marina Schwan

    2016-09-01

    Full Text Available Carbon aerogels are highly porous materials with a large inner surface area. Due to their high electrical conductivity they are excellent electrode materials in supercapacitors. Their brittleness, however, imposes certain limitations in terms of applicability. In that context, novel carbon aerogels with varying degree of flexibility have been developed. These highly porous, light aerogels are characterized by a high surface area and possess pore structures in the micrometer range, allowing for a reversible deformation of the aerogel network. A high ratio of pore size to particle size was found to be crucial for high flexibility. For dynamic microstructural analysis, compression tests were performed in-situ within a scanning electron microscope allowing us to directly visualize the microstructural flexibility of an aerogel. The flexible carbon aerogels were found to withstand between 15% and 30% of uniaxial compression in a reversible fashion. These findings might stimulate further research and new application fields directed towards flexible supercapacitors and batteries.

  2. Manufacturing Technology (MATES) II. Task Order 0006: Air Force Technology and Industrial Base Research Sub-Task 07: Future Advances in Electronic Materials and Processes-Flexible Hybrid Electronics

    Science.gov (United States)

    2016-02-29

    temporary handle die to make it manageable for processing, and then wafers were bumped to create Sn/Pb solder bumps on each die pad. A vacuum...Circuits and System Adaptation..............................................................208 7.3.5.1. Wafer Thinning...170 38 50-µm-thick Die Flip Chip Bonded with Sn/Pb Solder Bumps .......................................170 39 Flexible

  3. Micro-assembly of a Vascular-like Micro-channel with Railed Micro-robot Team-coordinated Manipulation

    Directory of Open Access Journals (Sweden)

    Huaping Wang

    2014-07-01

    strategies were evaluated based on the assembly of micro-donuts. Through the novel, designed, concentric movement of the multi-manipulators along the rail, arbitrary change of the approaching angle and the coordination posture was achieved to improve the micro-assembly’s flexibility. The operation range for every micromanipulator in different coordinated manipulation modes was analysed to avoid the breakdown of the assembled 3D structure. The image processing for the target location and end-effector identification was conducted to improve assembly efficiency in the micro-robot-team system. Finally, the assembly of the cellular vascular-like micro-channel was achieved with coordinated manipulation in the rail- guided micro-robot-team system.

  4. Flexible flapping wings can exhibit quasi-periodic motion!

    Science.gov (United States)

    Bose, Chandan; Sarkar, Sunetra

    2016-10-01

    The dynamics of a flexible flapping wing is investigated by modelling it as a coupled nonlinear fluid-structure interaction (FSI) system in the low Reynolds number flow regime in accordance to the flight of flapping wing micro air vehicles (MAVs). A bifurcation analysis, by varying the free-stream wind velocity (U ∞) as the control parameter, revealed the presence of a new dynamics in the form of a quasi-periodic attractor in the flapping wing motion. The structural and aerodynamic nonlinearities present in the system cause a supercritical Hopf bifurcation, where stable limit cycle oscillation emerges from fixed point response beyond a critical value of the free-stream velocity. Further increasing the control parameter, another bifurcation named Neimark-Sacker bifurcation takes place and as a result, the flapping wing exhibits quasi-periodic motion. The presence of Neimark-Sacker bifurcation in the flapping flow-field dynamics is an interesting find and the present work focuses on it's associated dynamical behaviour. Various dynamical system tools like frequency spectra, phase space, Poincaré section, first return map have been implemented successfully to confirm the presence of quasi-periodicity.

  5. Flexible network wireless transceiver and flexible network telemetry transceiver

    Science.gov (United States)

    Brown, Kenneth D.

    2008-08-05

    A transceiver for facilitating two-way wireless communication between a baseband application and other nodes in a wireless network, wherein the transceiver provides baseband communication networking and necessary configuration and control functions along with transmitter, receiver, and antenna functions to enable the wireless communication. More specifically, the transceiver provides a long-range wireless duplex communication node or channel between the baseband application, which is associated with a mobile or fixed space, air, water, or ground vehicle or other platform, and other nodes in the wireless network or grid. The transceiver broadly comprises a communication processor; a flexible telemetry transceiver including a receiver and a transmitter; a power conversion and regulation mechanism; a diplexer; and a phased array antenna system, wherein these various components and certain subcomponents thereof may be separately enclosed and distributable relative to the other components and subcomponents.

  6. Torsional natural frequency tuning by means of pneumatic flexible shaft couplings

    OpenAIRE

    2015-01-01

    This article deals with the use of pneumatic flexible shaft couplings as device for tuning torsional natural frequencies of mechanical systems. These couplings are using air bellows as flexible elements. Their torsional stiffness can be changed by air pressure change, the natural frequencies of whole mechanical system may be adjusted on desired value.

  7. Torsional natural frequency tuning by means of pneumatic flexible shaft couplings

    Directory of Open Access Journals (Sweden)

    Peter KAŠŠAY

    2015-12-01

    Full Text Available This article deals with the use of pneumatic flexible shaft couplings as device for tuning torsional natural frequencies of mechanical systems. These couplings are using air bellows as flexible elements. Their torsional stiffness can be changed by air pressure change, the natural frequencies of whole mechanical system may be adjusted on desired value.

  8. Painful Flexible Flatfoot.

    Science.gov (United States)

    Sheikh Taha, Abdel Majid; Feldman, David S

    2015-12-01

    Flatfoot is commonly encountered by pediatric orthopedic surgeons and pediatricians. A paucity of literature exists on how to define a flatfoot. The absence of the medial arch with a valgus hindfoot is the hallmark of this pathology. Flatfoot can be flexible or rigid. This review focuses on the diagnosis and treatment of the flexible flatfoot. Most flatfeet are flexible and clinically asymptomatic, and warrant little intervention. If feet are symptomatic, treatment is needed. Most patients who require treatment improve with foot orthotics and exercises. Only feet resistant to conservative modalities are deemed surgical candidates. The presence of a tight heel cord is often found in patients who fail conservative management.

  9. Flexible Support Stanchion

    Energy Technology Data Exchange (ETDEWEB)

    Rudland, D.L.; /Fermilab

    1987-05-11

    Figure 1 shows the assembly drawing of the Central Calorimeter Cryostat Flexible Support Stanchion. Figures 2 and 3 show the Flexible Support STanchion in detail. These Stanchions support the cryostat safely, reduce the heat load to the cryostat from the ambient by a factor of more than ten, provide a spring like action that reduce the loads created by thermal contraction of the cryostat and position the cryostate accurately. Table 1 shows all of the details of the Flexible Support system for the C.C. Cryostat.

  10. A Survey of Wireless Sensor Network Based Air Pollution Monitoring Systems.

    Science.gov (United States)

    Yi, Wei Ying; Lo, Kin Ming; Mak, Terrence; Leung, Kwong Sak; Leung, Yee; Meng, Mei Ling

    2015-12-12

    The air quality in urban areas is a major concern in modern cities due to significant impacts of air pollution on public health, global environment, and worldwide economy. Recent studies reveal the importance of micro-level pollution information, including human personal exposure and acute exposure to air pollutants. A real-time system with high spatio-temporal resolution is essential because of the limited data availability and non-scalability of conventional air pollution monitoring systems. Currently, researchers focus on the concept of The Next Generation Air Pollution Monitoring System (TNGAPMS) and have achieved significant breakthroughs by utilizing the advance sensing technologies, MicroElectroMechanical Systems (MEMS) and Wireless Sensor Network (WSN). However, there exist potential problems of these newly proposed systems, namely the lack of 3D data acquisition ability and the flexibility of the sensor network. In this paper, we classify the existing works into three categories as Static Sensor Network (SSN), Community Sensor Network (CSN) and Vehicle Sensor Network (VSN) based on the carriers of the sensors. Comprehensive reviews and comparisons among these three types of sensor networks were also performed. Last but not least, we discuss the limitations of the existing works and conclude the objectives that we want to achieve in future systems.

  11. Three-way flexible cantilever probes for static contact

    DEFF Research Database (Denmark)

    Wang, Fei; Petersen, Dirch Hjorth; Jensen, Helle Vendelbo;

    2011-01-01

    In micro four-point probe measurements, three-way flexible L-shaped cantilever probes show significant advantages over conventional straight cantilever probes. The L-shaped cantilever allows static contact to the sample surface which reduces the frictional wear of the cantilever tips. We analyze...

  12. The technology of microcircuit assembly on flexible polyimide substrate

    Directory of Open Access Journals (Sweden)

    Plis N. I.

    2010-10-01

    Full Text Available The research is devoted to technology of microcircuit assembly on flexible polyimide substrate. It is proved that such microcircuits provide high reliability and have advantage over other IC models when applied in hermetic micro-assemblies in microelectronic devices that operate under high accelerations, shocks and strong radiation.

  13. Novel imprinting techniques for fabrication of multilevel flexible electronics

    NARCIS (Netherlands)

    Turkenburg, D.H.; Rendering, H.; Hovestad, A.; Stroeks, N.; Maury, P.; Moonen, P.; Huskens, J.; Barbu, I.; Meinders, E.R.

    2011-01-01

    We report a novel method to selectively deposit materials from solution into imprinted micro-capillaries. Dewetting of the solvent just outside the capillaries is balanced to evaporation inside the capillaries. In this way conductive u-wires can be self-assembled and self-aligned on flexible

  14. Flexible Word Classes

    DEFF Research Database (Denmark)

    2013-01-01

    • First major publication on the phenomenon • Offers cross-linguistic, descriptive, and diverse theoretical approaches • Includes analysis of data from different language families and from lesser studied languages This book is the first major cross-linguistic study of 'flexible words', i.e. words...... that cannot be classified in terms of the traditional lexical categories Verb, Noun, Adjective or Adverb. Flexible words can - without special morphosyntactic marking - serve in functions for which other languages must employ members of two or more of the four traditional, 'specialised' word classes. Thus......, flexible words are underspecified for communicative functions like 'predicating' (verbal function), 'referring' (nominal function) or 'modifying' (a function typically associated with adjectives and e.g. manner adverbs). Even though linguists have been aware of flexible world classes for more than...

  15. Flexible displays, rigid designs?

    DEFF Research Database (Denmark)

    Hornbæk, Kasper

    2015-01-01

    Rapid technological progress has enabled a wide range of flexible displays for computing devices, but the user experience--which we're only beginning to understand--will be the key driver for successful designs....

  16. Flexibility in insulin prescription

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2016-01-01

    Full Text Available This communication explores the concept of flexibility, a propos insulin preparations and insulin regimes used in the management of type 2 diabetes. The flexibility of an insulin regime or preparation is defined as their ability to be injected at variable times, with variable injection-meal time gaps, in a dose frequency and quantum determined by shared decision making, with a minimal requirement of glucose monitoring and health professional consultation, with no compromise on safety, efficiency and tolerability. The relative flexibility of various basal, prandial and dual action insulins, as well as intensive regimes, is compared. The biopsychosocial model of health is used to assess the utility of different insulins while encouraging a philosophy of flexible insulin usage.

  17. Fuel Flexible Turbine System (FFTS) Program

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-12-31

    In this fuel flexible turbine system (FFTS) program, the Parker gasification system was further optimized, fuel composition of biomass gasification process was characterized and the feasibility of running Capstone MicroTurbine(TM) systems with gasification syngas fuels was evaluated. With high hydrogen content, the gaseous fuel from a gasification process of various feed stocks such as switchgrass and corn stover has high reactivity and high flashback propensity when running in the current lean premixed injectors. The research concluded that the existing C65 microturbine combustion system, which is designed for natural gas, is not able to burn the high hydrogen content syngas due to insufficient resistance to flashback (undesired flame propagation to upstream within the fuel injector). A comprehensive literature review was conducted on high-hydrogen fuel combustion and its main issues. For Capstone?s lean premixed injector, the main mechanisms of flashback were identified to be boundary layer flashback and bulk flow flashback. Since the existing microturbine combustion system is not able to operate on high-hydrogen syngas fuels, new hardware needed to be developed. The new hardware developed and tested included (1) a series of injectors with a reduced propensity for boundary layer flashback and (2) two new combustion liner designs (Combustion Liner Design A and B) that lead to desired primary zone air flow split to meet the overall bulk velocity requirement to mitigate the risk of core flashback inside the injectors. The new injector designs were evaluated in both test apparatus and C65/C200 engines. While some of the new injector designs did not provide satisfactory performance in burning target syngas fuels, particularly in improving resistance to flashback. The combustion system configuration of FFTS-4 injector and Combustion Liner Design A was found promising to enable the C65 microturbine system to run on high hydrogen biomass syngas. The FFTS-4 injector was

  18. Fuel Flexible Turbine System (FFTS) Program

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2012-12-31

    In this fuel flexible turbine system (FFTS) program, the Parker gasification system was further optimized, fuel composition of biomass gasification process was characterized and the feasibility of running Capstone MicroTurbine(TM) systems with gasification syngas fuels was evaluated. With high hydrogen content, the gaseous fuel from a gasification process of various feed stocks such as switchgrass and corn stover has high reactivity and high flashback propensity when running in the current lean premixed injectors. The research concluded that the existing C65 microturbine combustion system, which is designed for natural gas, is not able to burn the high hydrogen content syngas due to insufficient resistance to flashback (undesired flame propagation to upstream within the fuel injector). A comprehensive literature review was conducted on high-hydrogen fuel combustion and its main issues. For Capstone's lean premixed injector, the main mechanisms of flashback were identified to be boundary layer flashback and bulk flow flashback. Since the existing microturbine combustion system is not able to operate on high-hydrogen syngas fuels, new hardware needed to be developed. The new hardware developed and tested included (1) a series of injectors with a reduced propensity for boundary layer flashback and (2) two new combustion liner designs (Combustion Liner Design A and B) that lead to desired primary zone air flow split to meet the overall bulk velocity requirement to mitigate the risk of core flashback inside the injectors. The new injector designs were evaluated in both test apparatus and C65/C200 engines. While some of the new injector designs did not provide satisfactory performance in burning target syngas fuels, particularly in improving resistance to flashback. The combustion system configuration of FFTS-4 injector and Combustion Liner Design A was found promising to enable the C65 microturbine system to run on high hydrogen biomass syngas. The FFTS-4 injector

  19. 柔性航天器姿控执行机构微振动集中隔离与分散隔离对比研究%Comparison of concentrated and distributed isolations of micro vibrations in flexible spacecraft attitude actuators

    Institute of Scientific and Technical Information of China (English)

    李静; 庞岩; 冯咬齐; 刘磊

    2016-01-01

    The attitude stability of flexible spacecrafts is reduced because of micro vibrations resulting from rotating attitude control actuators. In this paper, the concentrated vibration isolation and the distributed vibration isolation are studied in the context of high stability pointing. At first, the attitude dynamics model for the flexible spacecraft containing vibration isolators is established. Then, the performances of the passive concentrated vibration isolation and the distributed vibration isolation for the attitude actuators are compared by using the simulation method. It is indicated that by using high-stiffness isolators, the concentrated vibration isolation has a similar performance as the distributed vibration isolation in the satellite maneuvering processes. Using the low-stiffness isolators, the concentrated vibration isolation loses stability more easily than the distributed vibration isolation. The concentrated and distributed vibration isolations have similar performances for attitude stabilizing with both the high-stiffness or the low-stiffness isolators.%姿控执行机构高速旋转诱发的微振动会降低柔性航天器姿态稳定度.为实现高稳指向,文章研究了姿控执行机构的集中隔振与分散隔振技术.首先建立包含隔振器的柔性航天器姿态动力学模型;然后仿真研究航天器在作大角度机动和稳定控制两种工况下,姿控执行机构的两种隔振方案的性能,并进行了对比分析.研究结果表明:航天器进行大角度机动时,对于高刚度隔振器,两种隔振均具有稳定性,并且指向控制性能相似;对于低刚度隔振器,集中隔振较分散隔振容易失稳;在稳定控制工况下,对于高刚度隔振器和低刚度隔振器,两种隔振性能基本一致.

  20. COUPLING EFFECT OF FLEXIBLE JOINT AND FLEXIBLE LINK ON DYNAMIC SINGULARITY OF FLEXIBLE MANIPULATOR

    Institute of Scientific and Technical Information of China (English)

    GAO Zhihui; YUN Chao; BIAN Yushu

    2008-01-01

    The coupling effect of the flexible joint and the flexible link on the dynamic singularity of the flexible manipulator is addressed. Firstly, the dynamic equations of a flexible manipulator with a flexible joint and a flexible link are derived. Secondly, the relationship and property between the flexible joint and the flexible link are analyzed. It shows that the flexible joint's amplitude will increase abruptly, thereby the dynamic singularity occurs if the frequency of a flexible joint is near or equal to some natural frequency of a flexible link. Finally, some numerical simulations which will verify the correctness of the theoretical analysis, are carried out. The results are fundamental for the design of a flexible manipulator and for the avoidance of the dynamic singularity.

  1. Micro Marketing

    Institute of Scientific and Technical Information of China (English)

    Yu Yan

    2012-01-01

    In November the Chinese movie industry experienced a startling surprise.Love Is Not Blind,a low-budget movie with no prominent director or major star,hit 344.8million yuan ($54.5 million) in box office revenue,despite the film's budget was only 9 million yuan ($1.4 million).The film,which tells the 33-day experience of a girl named Huang Xiaoxian after she breaks up with her boyfriend,owes its unexpected blockbusting success to its innovative marketing strategy:micro-blog marketing.The number of followers of the official micro-blog for Love Is Not Blind hit nearly 100,000,attracted by rccommendations of related micro-blog messages,impressive box office lines,and positive word of mouth.By December 7,search queries for Love Is Not Blind had exceeded 8 million.Those for Wang Xiaojian,the lcading male,were close to 1.5 million.

  2. [Flexible print circuit technology application in biomedical engineering].

    Science.gov (United States)

    Jiang, Lihua; Cao, Yi; Zheng, Xiaolin

    2013-06-01

    Flexible print circuit (FPC) technology has been widely applied in variety of electric circuits with high precision due to its advantages, such as low-cost, high specific fabrication ability, and good flexibility, etc. Recently, this technology has also been used in biomedical engineering, especially in the development of microfluidic chip and microelectrode array. The high specific fabrication can help making microelectrode and other micro-structure equipment. And good flexibility allows the micro devices based on FPC technique to be easily packaged with other parts. In addition, it also reduces the damage of microelectrodes to the tissue. In this paper, the application of FPC technology in biomedical engineering is introduced. Moreover, the important parameters of FPC technique and the development trend of prosperous applications is also discussed.

  3. Moving target geolocation for micro air vehicles based on monocular vision%基于单目视觉的微型飞行器移动目标定位方法

    Institute of Scientific and Technical Information of China (English)

    郭力; 昂海松; 郑祥明

    2012-01-01

    针对目标在地形高度未知环境中移动的情况,给出一种利用微型飞行器机载单目摄像机进行目标定位的方法.首先,借助光流直方图从当前图像帧中提取出移动目标局部区域内的背景特征点;然后,结合机载微机电系统(micro electro mechanical system,MEMS)/全球定位系统(global positioning system,GPS)传感器测量的飞行器位姿和空间平面点成像的单应变换关系,在期望值最大化算法中将背景特征点分类为辅助平面点和非辅助平面点,并估计辅助平面到摄像机光心的距离参数和法矢量参数,从而确定移动目标所处辅助平面的空间平面方程;最后,联立求解目标视线方程和辅助平面方程获得交点坐标,转换到惯性系下完成移动目标的地理定位.实验结果表明,当微型飞行器飞行高度为100 m时,操作人员单次点击移动目标的定位误差在15 m以内.%Aiming at the movement of the targets in unknown altitude terrain, a monocular camera based target geolocation method for micro air vehicles (MAV) is presented. Firstly, the optical flow histgram algorithm extracts background features in the target's local region. Secondly, these features are clustered into two possible classes including aided plane features and non-aided plane features by the expectation maximization algorithm, in which the homography relationship between MAV's flight status measured by onboard micro electro mechanical systems (MEMS)/ global positioning system (GPS) sensors and planar is used. Meanwile, the normal vector of aided plane and the distance between the camera and the plane are estimated. Then the aided plane equation can be establised. Finally, the moving taregt can be geolocated by calculating the intersection of target's sight line and aided plane in inertial frame. Experimental results show that this method can instantaneously geolocate the moving target by operator's single click and the error can reach less than

  4. 基于单目视觉的室内微型飞行器位姿估计与环境构建%Monocular Vision Based Motion Estimation of Indoor Micro Air Vehicles and Structure Recovery

    Institute of Scientific and Technical Information of China (English)

    郭力; 昂海松; 郑祥明

    2012-01-01

    Micro air vehicles (MAVs) need reliable attitude and position information in indoor environment. The measurements of onboard inertial measurement unit (IMU) sensors such as gyros and acce-larometers are corrupted by large accumulated errors, and GPS signal is unavailable in such situation. Therefore, a monocular vision based indoor MAV motion estimation and structure recovery method is presented. Firstly, the features are tracked by biological vision based matching algorithm through the image sequence, and the motion of camra is estimated by the five-point algorithm. In the indoor enviro-ment, the planar relationship is used to reduce the feature point dimentions from three to two. Then, these parameters are optimized by an local strategy to improve the motion estimation and structure recovery accuracy. The measurements of IMU sensors and vision module are fused with extended Kalman fileter. The attitude and position information of MAVs is estimated. The experiment shows that the method can reliably estimate the indoor motion of MAV in real-time, and the recovered enviroment information can be used for navigation of MAVs.%针对微型飞行嚣(Micro air vehicle,MAV)在室内飞行过程中无法获得GPS信号,而微型惯性单元(Inertial measurement unit,IMU)的陀螺仪和加速度计随机漂移误差较大,提出一种利用单目视觉估计微型飞行嚣位姿并构建室内环境的方法.在机载单目摄像机拍摄的序列图像中引入一种基于生物视觉的方法获得匹配特征点,并由五点算法获得帧间摄像机运动参数和特征点位置参数的初始解;利用平面关系将特征点的位置信息由三维降低到二维,给出一种局部优化方法求解摄像机运动参数和特征点位置参数的最大似然估计,提高位姿估计和环境构建的精度.最后通过扩展卡尔曼滤波方法融合IMU传感器和单目视觉测量信息解算出微型飞行器的位姿.实验结果表明,该方法能够实时可

  5. Comparison of air-agitated liquid-liquid microextraction technique and conventional dispersive liquid-liquid micro-extraction for determination of triazole pesticides in aqueous samples by gas chromatography with flame ionization detection.

    Science.gov (United States)

    Farajzadeh, Mir Ali; Mogaddam, Mohammad Reza Afshar; Aghdam, Abdollah Abdollahi

    2013-07-26

    Two micro-extraction methods, air-agitated liquid-liquid microextraction (AALLME) and dispersive liquid-liquid microextraction (DLLME), have been compared with each other by applying them for the analysis of five triazole pesticides (penconazole, hexaconazole, diniconazole, tebuconazole and triticonazole) in aqueous samples by gas chromatography with flame ionization detection (GC-FID). In the AALLME method, which excludes any disperser solvent, much less volume of organic solvent is used. In order to form fine and dispersed organic droplets in the aqueous phase, the mixture of aqueous sample solution and extraction solvent is repeatedly aspirated and dispensed with a syringe. In the DLLME method, an appropriate mixture of extraction solvent and disperser solvent is rapidly injected by a syringe into the aqueous sample. Effect of the pertinent experimental factors on DLLME (i.e. identity and volume of the extraction and disperser solvents and ionic strength) and on AALLME (identity and volume of the extraction solvent, number of agitations, and ionic strength) were investigated. Under optimal conditions, limits of detection for the five target pesticides obtained by AALLME-GC-FID and DLLME-GC-FID ranged from 0.20 to 1.1ngmL(-1) and 1.9 to 5.9ngmL(-1), respectively. The relative standard deviations (RSDs, n=5) were in the range of 1-4% and 3-5% with the enrichment factors of 449-504 and 79-143 for AALLME-GC-FID and DLLME-GC-FID, respectively. Both of the compared methods are simple, fast, efficient, inexpensive and can be applied to the analysis of the five pesticides in different aqueous samples in which penconazole and hexaconazole were found. For spiked samples, the recoveries were in the ranges of 92-105%, and 92-104% for AALLME and DLLME, respectively.

  6. Simultaneous analysis of organochlorine pesticides and polychlorinated biphenyls in air samples by using accelerated solvent extraction (ASE) and solid-phase micro-extraction (SPME) coupled to gas chromatography dual electron capture detection.

    Science.gov (United States)

    Mokbel, Haifaa; Al Dine, Enaam Jamal; Elmoll, Ahmad; Liaud, Céline; Millet, Maurice

    2016-04-01

    An analytical method associating accelerated solvent extraction (ASE) and solid-phase micro-extraction (SPME) in immersion mode combined with gas chromatography dual electrons capture detectors (SPME-GC-2ECD) has been developed and studied for the simultaneous determination of 19 organochlorine pesticides (OCPs) and 22 polychlorinated biphenyls (PCBs) in air samples (active and XAD-2 passive samplers). Samples were extracted with ASE with acetonitrile using the following conditions: temperature, 150 °C; pressure, 1500 psi; static, 15 min; cycles, 3; purge, 300 s; flush, 100 %. Extracts were reduced to 1 mL, and 500 μL of this extract, filled with deionised water, was subject to SPME extraction. Experimental results indicated that the proposed method attained the best extraction efficiency under the optimised conditions: extraction of PCB-OCP mixture using 100-μm PDMS fibre at 80 °C for 40 min with no addition of salt. The performance of the proposed ASE-SPME-GC-2ECD methodology with respect to linearity, limit of quantification and detection was evaluated by spiking of XAD-2 resin with target compounds. The regression coefficient (R (2)) of most compounds was found to be high of 0.99. limits of detection (LODs) are between 0.02 and 4.90 ng m(-3), and limits of quantification (LOQs) are between 0.05 and 9.12 ng m(-3) and between 0.2 and 49 ng/sampler and 0.52 and 91 ng/sampler, respectively, for XAD-2 passive samplers. Finally, a developed procedure was applied to determine selected PCBs and OCPs in the atmosphere.

  7. Soft dentin results in unique flexible teeth in scraping catfishes.

    Science.gov (United States)

    Geerinckx, Tom; Huysseune, Ann; Boone, Matthieu; Claeys, Myriam; Couvreur, Marjolein; De Kegel, Barbara; Mast, Peter; Van Hoorebeke, Luc; Verbeken, Kim; Adriaens, Dominique

    2012-01-01

    Teeth are generally used for actions in which they experience mainly compressive forces acting toward the base. The ordered tooth enamel(oid) and dentin structures contribute to the high compressive strength but also to the minor shear and tensile strengths. Some vertebrates, however, use their teeth for scraping, with teeth experiencing forces directed mostly normal to their long axis. Some scraping suckermouth catfishes (Loricariidae) even appear to have flexible teeth, which have not been found in any other vertebrate taxon. Considering the mineralized nature of tooth tissues, the notion of flexible teeth seems paradoxical. We studied teeth of five species, testing and measuring tooth flexibility, and investigating tooth (micro)structure using transmission electron microscopy, staining, computed tomography scanning, and scanning electron microscopy-energy-dispersive spectrometry. We quantified the extreme bending capacity of single teeth (up to 180°) and show that reorganizations of the tooth (micro)structure and extreme hypomineralization of the dentin are adaptations preventing breaking by allowing flexibility. Tooth shape and internal structure appear to be optimized for bending in one direction, which is expected to occur frequently when feeding (scraping) under natural conditions. Not all loricariid catfishes possess flexible teeth, with the trait potentially having evolved more than once. Flexible teeth surely rank among the most extreme evolutionary novelties in known mineralized biological materials and might yield a better understanding of the processes of dentin formation and (hypo)mineralization in vertebrates, including humans.

  8. Análisis tafonómico de micromamíferos y mesomamíferos del sitio Laguna La Barrancosa 1 (Partido de Benito Juárez, provincia de Buenos Aires Taphonomic Analysis Of Micro And Mesomammal Bones From Laguna La Barrancosa 1 Archaeological Site (District Of Benito Juárez, Buenos Aires Province

    Directory of Open Access Journals (Sweden)

    Gustavo N. Gómez

    2008-12-01

    Full Text Available En este trabajo se presentan los resultados obtenidos del análisis cuantitativo y tafonómico de las especies de micro y mesomamíferos recuperadas en el sitio Laguna La Barrancosa 1 (Partido de Benito Juárez, provincia de Buenos Aires. Distintos métodos analíticos (macroscópicos y microscópicos -MEB- fueron empleados en dicho análisis. Los índices utilizados para comparar la representación del esqueleto postcraneal frente al craneal (pc/c y f+h/md+mx indican que existe una mayor representación de este último, señalando que determinados agentes post-deposicionales han producido la pérdida de algunas partes esqueletarias. Estos agentes y los efectos de la corrosión producida por las raíces, así como las condiciones sedimentarias, han sido los principales modificadores de la superficie cortical de los restos óseos de micro y mesomamíferos. En el conjunto óseo analizado no se han detectado efectos producidos por la digestión de depredadores ni marcas de carnívoros, indicando que los restos de estas especies fosoriales no fueron incorporados por ninguna cadena trófica. Además, no se registraron evidencias de la acción antrópica sobre los restos óseos (e.g., marcas de corte, huesos quemados, etc. y se plantea que los mismos corresponden a especies que habitaron y murieron in situ. Las cuevas registradas en el sitio y las marcas de roedores sobre algunos de los huesos de Lama guanicoe señalan que estas especies actuaron como agentes modificadores post-depositacionales del conjunto arqueológico.In this paper, results are presented from quantitative and taphonomic analyses of micro and mesomammal bones recovered from Laguna La Barrancosa 1 archaeological site. The analytical methods used included macroscopic and microscopic (SEM techniques. The rates used (pc/c y f+h/md+mx show that there is a greater representation of cranial elements than postcranial due to diagenetical agents, which were the principal cause of the loss of

  9. A CAMAC and FASTBUS engineering test environment supported by a MicroVAX/MicroVMS system

    Energy Technology Data Exchange (ETDEWEB)

    Logg, C.A.

    1987-10-01

    A flexible, multiuser engineering test environment has been established for the engineers in SLAC's Electronic Instrumentation Engineering group. The system hardware includes a standard MicroVAX II and MicroVAX I with multiple CAMAC, FASTBUS, and GPIB instrumentation buses. The system software components include MicroVMS licenses with DECNET/SLACNET, FORTRAN, PASCAL, FORTH, and a versatile graphical display package. In addition, there are several software utilities available to facilitate FASTBUS and CAMAC prototype hardware debugging. 16 refs., 7 figs.

  10. Flexible magnetoimpedance sensor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bodong; Kavaldzhiev, Mincho N.; Kosel, Jürgen, E-mail: jurgen.kosel@kaust.edu.sa

    2015-03-15

    Flexible magnetoimpedance (MI) sensors fabricated using a NiFe/Cu/NiFe tri-layer on Kapton substrate have been studied. A customized flexible microstrip transmission line was employed to investigate the MI sensors's magnetic field and frequency responses and their dependence on the sensors's deflection. For the first time, the impedance characteristic is obtained through reflection coefficient analysis over a wide range of frequencies from 0.1 MHz to 3 GHz and for deflections ranging from zero curvature to a radius of 7.2 cm. The sensor element maintains a high MI ratio of up to 90% and magnetic sensitivity of up to 9.2%/Oe over different bending curvatures. The relationship between the curvature and material composition is discussed based on the magnetostriction effect and stress simulations. The sensor's large frequency range, simple fabrication process and high sensitivity provide a great potential for flexible electronics and wireless applications. - Highlights: • A flexible magnetoimpedance (MI) sensor is developed. • Studies are carried out using a flexible microstrip transmission line. • An MI ratio of up to 90% is obtained. • The effect of magnetostriction is studied.

  11. Micro system comprising 96 micro valves on a titer plate

    Science.gov (United States)

    Krabbe, S.; Flitsch, D.; Büchs, J.; Schomburg, W. K.

    2016-10-01

    A system of 96 micro valves has been developed and mounted on top of a 48-well micro titer plate providing two valves for each well controlling its air inlet and outlet. Testing of the valve system showed that all valves are working and are opened and closed reliably. A pneumatic system is switching inlet and outlet valves independently of each other. The geometry of the feed channels ensures an equal air flow through all wells, when the valves are open. Between the micro valves, one optical fibre was inserted through the lid of each well allowing measuring the oxygen partial pressure in the enclosed air volume by fluorescence sensor spots. Escherichia coli bacteria were grown inside the wells and their metabolism was observed by the oxygen partial pressure change due to respiration. In all 48 wells, the same oxygen transfer rate was observed within an averaged standard deviation of 1 mmol/L/h. The oxygen transfer rate differences compared to a macroscopic standard shake flask system were overall compatible within their uncertainties.

  12. Flexible magnetoimpedance sensor

    KAUST Repository

    Li, Bodong

    2015-03-01

    Flexible magnetoimpedance (MI) sensors fabricated using a NiFe/Cu/NiFe tri-layer on Kapton substrate have been studied. A customized flexible microstrip transmission line was employed to investigate the MI sensors\\'s magnetic field and frequency responses and their dependence on the sensors\\'s deflection. For the first time, the impedance characteristic is obtained through reflection coefficient analysis over a wide range of frequencies from 0.1 MHz to 3 GHz and for deflections ranging from zero curvature to a radius of 7.2 cm. The sensor element maintains a high MI ratio of up to 90% and magnetic sensitivity of up to 9.2%/Oe over different bending curvatures. The relationship between the curvature and material composition is discussed based on the magnetostriction effect and stress simulations. The sensor\\'s large frequency range, simple fabrication process and high sensitivity provide a great potential for flexible electronics and wireless applications.

  13. Pneumatic flexible shaft couplings

    Directory of Open Access Journals (Sweden)

    Jaroslav HOMIŠIN

    2007-01-01

    Full Text Available Main effort of every design engineer is reduction of torsional oscillation in any mechanical system. At present this problem can be solved by means of a suitable modification of dynamic properties of flexible shaft couplings according to dynamics in the given systems. But the dynamic properties of nowadays-applied flexible couplings arenot unchangeable because of aging and fatigue processes occurring in flexible coupling elements. Result of this fact causes detuning of mechanical system. Taking into consideration the above-mentioned situation, we suggest for mechanical systems application of a newly developed pneumatic couplings that have constant characteristicfeatures during the whole current operation and thus they have a positive influence on the system running.

  14. Designing structural supply chain flexibility

    OpenAIRE

    Mulinski, Ksawery Jan

    2012-01-01

    In a continuously changing business environment the role of supply chain flexibility is constantly increasing. A flexible supply chain can ensure survival in quickly changing market conditions as well as enable sustainable growth. This thesis explores the topic of supply chain flexibility with focus on structural flexibility due to scarcity of previous research in that area. The purpose of the research is to answer a question: how can companies design structural supply chain flexibility? In a...

  15. Smart Heat and Power: Utilizing the Flexibility of Micro Cogeneration

    NARCIS (Netherlands)

    Houwing, M.

    2010-01-01

    Distributed generation (DG) contributes to a more sustainable electricity supply. Large-scale adoption of DG will bring radical changes to the traditional model of generation and supply as well as to the business model of the power industry. Furthermore, with innovations in information and

  16. Topology optimization of flexible micro-fluidic devices

    DEFF Research Database (Denmark)

    Kreissl, Sebastian; Pingen, Georg; Evgrafov, Anton

    2010-01-01

    in the undeformed and deformed configurations. The layout of fluid channels is determined by material topology optimization. In addition, the thickness distribution, the distribution of active material for internal actuation, and the support conditions are optimized. The coupled fluid-structure response...... and fluid mesh. The governing and the adjoint equations of the resulting fluid-structure interaction problem are derived. The proposed method is illustrated with the design of tunable manifolds....

  17. Topology optimization of flexible micro-fluidic devices

    DEFF Research Database (Denmark)

    Kreissl, Sebastian; Pingen, Georg; Evgrafov, Anton;

    2010-01-01

    A multi-objective topology optimization formulation for the design of dynamically tunable fluidic devices is presented. The flow is manipulated via external and internal mechanical actuation, leading to elastic deformations of flow channels. The design objectives characterize the performance...

  18. Smart Heat and Power: Utilizing the Flexibility of Micro Cogeneration

    NARCIS (Netherlands)

    Houwing, M.

    2010-01-01

    Distributed generation (DG) contributes to a more sustainable electricity supply. Large-scale adoption of DG will bring radical changes to the traditional model of generation and supply as well as to the business model of the power industry. Furthermore, with innovations in information and communica

  19. Scalable, Self Aligned Printing of Flexible Graphene Micro Supercapacitors (Postprint)

    Science.gov (United States)

    2017-05-11

    structures with greatly relaxed printing tolerance. Leveraging this process with pristine graphene and ion gel inks, miniaturized all-solid-state graphene...MSCs are demonstrated to concurrently achieve outstanding resolution ( active footprint: ə mm2, minimum feature size: 20 μm) and yield (44/44 devices...greatly relaxed printing tolerance. Leveraging this process with pristine graphene and ion gel inks, miniaturized all-solid-state graphene MSCs are

  20. Rapid Generation of MicroRNA Sponges for MicroRNA Inhibition

    NARCIS (Netherlands)

    Kluiver, Joost; Gibcus, Johan H.; Hettinga, Chris; Adema, Annelies; Richter, Mareike K. S.; Halsema, Nancy; Slezak-Prochazka, Izabella; Ding, Ye; Kroesen, Bart-Jan; van den Berg, Anke

    2012-01-01

    MicroRNA (miRNA) sponges are transcripts with repeated miRNA antisense sequences that can sequester miRNAs from endogenous targets. MiRNA sponges are valuable tools for miRNA loss-of-function studies both in vitro and in vivo. We developed a fast and flexible method to generate miRNA sponges and tes

  1. Rapid Generation of MicroRNA Sponges for MicroRNA Inhibition

    NARCIS (Netherlands)

    Kluiver, Joost; Gibcus, Johan H.; Hettinga, Chris; Adema, Annelies; Richter, Mareike K. S.; Halsema, Nancy; Slezak-Prochazka, Izabella; Ding, Ye; Kroesen, Bart-Jan; van den Berg, Anke

    2012-01-01

    MicroRNA (miRNA) sponges are transcripts with repeated miRNA antisense sequences that can sequester miRNAs from endogenous targets. MiRNA sponges are valuable tools for miRNA loss-of-function studies both in vitro and in vivo. We developed a fast and flexible method to generate miRNA sponges and

  2. Capillary origami of micro-machined micro-objects: Bi-layer conductive hinges

    NARCIS (Netherlands)

    Legrain, A.; Berenschot, J.W.; Tas, N.R.; Abelmann, L.

    2015-01-01

    Recently, we demonstrated controllable 3D self-folding by means of capillary forces of silicon-nitride micro-objects made of rigid plates connected to each other by flexible hinges (Legrain et al., 2014). In this paper, we introduce platinum electrodes running from the substrate to the plates over t

  3. Thin flexible intercalation anodes

    Energy Technology Data Exchange (ETDEWEB)

    Levy, S.C.; Cieslak, W.R.; Klassen, S.E.; Lagasse, R.R.

    1994-10-01

    Poly(acrylonitrile) fibers have been pyrolyzed under various conditions to form flexible carbon yarns capable of intercalating lithium ions. These fibers have also been formed into both woven and non woven cloths. Potentiostatic, potentiodynamic and galvanostatic tests have been conducted with these materials in several electrolytes. In some tests, a potential hold was used after each constant current charge and discharge. These tests have shown some of these flexible materials to reversibly intercalate lithium ions to levels that are suitable for use as a practical battery anode.

  4. A Micro Hydrogen Air Fuel Cell

    Science.gov (United States)

    2005-10-01

    Monomers The nomenclature rationale is that the first letter tells whether the copolymer is random (R) or block (B). The second letter defines the co...We believe that the peak corresponds to carbonyls of anhydride end groups of degraded polyimide. There are several reasons for proposing that the...peak at 1785 cm- 1 is for the anhydride end groups. The C=O stretching band for anhydride groups of 1,4,5,8- naphthalenetetracarboxylic dianhydride

  5. Autonomous Aerodynamic Control of Micro Air Vehicles

    Science.gov (United States)

    2009-10-19

    technique based on the aerodynamic derivatives and gains set by the user. The user-set gains remain the same, but gains calculated from the...vehicle (MAV) research. Among these are: advanced modeling and simulation models for MAVs, aero-structural interaction, advanced guidance techniques ...flight. A. Wing-Fuselage Joint and Spring Mechanism Piano hinges are used to connect each wing to the fuselage and limit the wing motion to deflect

  6. Center for Micro Air Vehicle Studies

    Science.gov (United States)

    2013-02-01

    SUPPLEMENTARY NOTES PA Case Number: 88ABW-2013-1337; Clearance Date: 20 Mar 2013. Report contains color. 14. ABSTRACT This report summarizes the...shown in Figure 32 contains a costa, subcosta, radius and cubitus. The radius contains two branches that spread out to cover the surface area of the...were considered; the cone, disk, toroidal , and magnetic CVTs. The cone CVT was selected for further development based on the openness of its

  7. A tunable microflow focusing device utilizing controllable moving walls and its applications for formation of micro-droplets in liquids

    Science.gov (United States)

    Lee, Chun-Hong; Hsiung, Suz-Kai; Lee, Gwo-Bin

    2007-06-01

    This study reports a new microfluidic device capable of fine-tuned sample-flow focusing and generation of micro-droplets in liquids by controlling moving wall structures. Two microfluidic components including an 'active microchannel width controller' and a 'micro chopper' can be used to fine-tune the width of the hydrodynamically pre-focused stream and subsequently generate micro-droplets. In this study, a basic concept of a 'controllable moving wall' structure was addressed and applied as the active microchannel width controller and the micro chopper to generate the proposed function. Pneumatic side chambers were placed next to a main flow channel to construct the controllable moving wall structures. The deformation of the controllable moving wall structure can be generated by the pressurized air injected into the pneumatic side chambers. The proposed chip device was fabricated utilizing polymer material such as PDMS (polydimethylsiloxane) to provide the flexibility of the controllable moving wall deformation. The microfluidic chip device with dimensions of 2.5 cm in width and 3.0 cm in length can be fabricated using a simple fabrication process. Experimental data showed that the deformation of the controllable moving wall structure can be adjusted by applying different air pressures, so that the width of the main flow channel can be controlled accordingly. By utilizing the proposed mechanism, the pre-focused dispersed phase stream could be actively focused into a narrower stream, and well-controlled micro-droplets with smaller diameters could be generated. The stream width can be reduced from 30 µm to 9 µm and micro-droplets with a diameter of 76 µm could be generated by utilizing the proposed device. In addition, to generate micro-droplets within smaller diameters, uniform size distribution of the micro-droplets can be obtained. According to the experimental results, development of the microfluidic device could be promising for a variety of applications such

  8. Movable MEMS Devices on Flexible Silicon

    KAUST Repository

    Ahmed, Sally

    2013-05-05

    Flexible electronics have gained great attention recently. Applications such as flexible displays, artificial skin and health monitoring devices are a few examples of this technology. Looking closely at the components of these devices, although MEMS actuators and sensors can play critical role to extend the application areas of flexible electronics, fabricating movable MEMS devices on flexible substrates is highly challenging. Therefore, this thesis reports a process for fabricating free standing and movable MEMS devices on flexible silicon substrates; MEMS flexure thermal actuators have been fabricated to illustrate the viability of the process. Flexure thermal actuators consist of two arms: a thin hot arm and a wide cold arm separated by a small air gap; the arms are anchored to the substrate from one end and connected to each other from the other end. The actuator design has been modified by adding etch holes in the anchors to suit the process of releasing a thin layer of silicon from the bulk silicon substrate. Selecting materials that are compatible with the release process was challenging. Moreover, difficulties were faced in the fabrication process development; for example, the structural layer of the devices was partially etched during silicon release although it was protected by aluminum oxide which is not attacked by the releasing gas . Furthermore, the thin arm of the thermal actuator was thinned during the fabrication process but optimizing the patterning and etching steps of the structural layer successfully solved this problem. Simulation was carried out to compare the performance of the original and the modified designs for the thermal actuators and to study stress and temperature distribution across a device. A fabricated thermal actuator with a 250 μm long hot arm and a 225 μm long cold arm separated by a 3 μm gap produced a deflection of 3 μm before silicon release, however, the fabrication process must be optimized to obtain fully functioning

  9. Flexible energy systems

    DEFF Research Database (Denmark)

    Lund, Henrik

    2003-01-01

    The paper discusses and analyses diffent national strategies and points out key changes in the energy system in order to achieve a system which can benefit from a high percentage of wind and CHP without having surplus production problems, introduced here as a flexible energy system....

  10. Flexible Classroom Furniture

    Science.gov (United States)

    Kim Hassell,

    2011-01-01

    Classroom design for the 21st-century learning environment should accommodate a variety of learning skills and needs. The space should be large enough so it can be configured to accommodate a number of learning activities. This also includes furniture that provides flexibility and accommodates collaboration and interactive work among students and…

  11. Flexible Language Interoperability

    DEFF Research Database (Denmark)

    Ekman, Torbjörn; Mechlenborg, Peter; Schultz, Ulrik Pagh

    2007-01-01

    of the language. In this paper, we present a highly flexible yet efficient approach to hosting multiple programming languages on an object-oriented virtual machine. Our approach is based on extending the interface of each class with language-specific wrapper methods, offering each language a tailored view...

  12. Flexible Mental Calculation.

    Science.gov (United States)

    Threlfall, John

    2002-01-01

    Suggests that strategy choice is a misleading characterization of efficient mental calculation and that teaching mental calculation methods as a whole is not conducive to flexibility. Proposes an alternative in which calculation is thought of as an interaction between noticing and knowledge. Presents an associated teaching approach to promote…

  13. Flexible cultural repertoires

    DEFF Research Database (Denmark)

    Lindegaard, Marie Rosenkrantz; Zimmermann, Francisca

    2017-01-01

    rejection of crime-involved youth. Young men who perform flexible cultural repertoires, by incorporating and shifting between gang and decent repertoires, experience low victimization due to their adaptation to crime-involved youth. Findings emphasize the importance of detailed investigations of the way...

  14. Flexible metal bellows

    CERN Multimedia

    1975-01-01

    A set of flexible metal bellows being fatigue-tested by repeated offset motion. Such bellows assemblies were used in the SPS vacuum system at places where , for instance, beam stoppers and collimators had to be moved frequently in and out of the beam path.

  15. Flexible Query Answering Systems

    DEFF Research Database (Denmark)

    This book constitutes the refereed proceedings of the 12th International Conference on Flexible Query Answering Systems, FQAS 2017, held in London, UK, in June 2017. The 21 full papers presented in this book together with 4 short papers were carefully reviewed and selected from 43 submissions...

  16. Engineering Design of Driving System for Flapping-Wing Micro Air Vehicles%微型扑翼飞行器驱动系统工程设计方法

    Institute of Scientific and Technical Information of China (English)

    王利光; 宋笔锋; 付鹏; 安伟刚

    2013-01-01

    以微型扑翼飞行器研制为背景,从系统的角度提出了一种仿生扑翼驱动系统的工程设计方法.根据仿生尺度率原理,对微型扑翼飞行器的总体参数进行了初步设计,提出了驱动系统的设计目标.进行了扑动翼风洞实验,以实际能达到的飞行状态为标准对实验数据进行分析处理,获得了扑动参数的可行范围和功耗需求.对微型无刷电机进行了工作特性测试,得到了电机转速、转矩、输出功率、效率等的拟合关系.综合考虑扑动参数可行范围、功耗需求和电机特性等多个因素,对驱动系统的减速比分配、减速器优化和四连杆扑动机构计算等方面进行了设计,得到了具有良好系统匹配性能的微型扑翼驱动系统,并通过样机研制和飞行实验证明了设计方法的有效性与可行性.所得研究结论对微型扑翼飞行器的工程设计和研制有一定指导意义.%For developing an efficient flapping-wing micro air vehicle (FMAV),an engineering design method for flappingwing driving system is systematically proposed.According to the principle of bionic scale law,the initial design of FMAV is carried out and the goal of flapping-wing driving system design is specified.The feasible flutter parameters and power requirements of the flapping-wing are demonstrated by the wind tunnel experiments which are processed submitting to the practical flying status.After carrying out another test,the micro brushless motor's operating characteristics of angular speed,torque,power output and efficiency are achieved.Then the feasible flutter parameters,power requirements and motor's operating characteristics are comprehensively considered,which make the assignation of the reduction ratio,optimization of the reduction gear and design of the four-link mechanism concordant.The mechanism prototype's flying tests verify the effectiveness and feasibility of this design approach.The results of this research are

  17. Adding flexibility to physician training.

    Science.gov (United States)

    Mahady, Suzanne E

    2011-05-02

    Demographic changes among junior doctors are driving demand for increased flexibility in advanced physician training, but flexible training posts are lacking. Suitable flexible training models include flexible full-time, job-share and part-time positions. Major barriers to establishing flexible training positions include difficulty in finding job-share partners, lack of funding for creating supernumerary positions, and concern over equivalence of educational quality compared with full-time training. Pilot flexible training positions should be introduced across the medical specialties and educational outcomes examined prospectively.

  18. Aggregating energy flexibilities under constraints

    DEFF Research Database (Denmark)

    Valsomatzis, Emmanouil; Pedersen, Torben Bach; Abello, Alberto

    2016-01-01

    The flexibility of individual energy prosumers (producers and/or consumers) has drawn a lot of attention in recent years. Aggregation of such flexibilities provides prosumers with the opportunity to directly participate in the energy market and at the same time reduces the complexity of scheduling...... the energy units. However, aggregated flexibility should support normal grid operation. In this paper, we build on the flex-offer (FO) concept to model the inherent flexibility of a prosumer (e.g., a single flexible consumption device such as a clothes washer). An FO captures flexibility in both time...

  19. Ultrathin flexible dual band terahertz absorber

    Science.gov (United States)

    Shan, Yan; Chen, Lin; Shi, Cheng; Cheng, Zhaoxiang; Zang, Xiaofei; Xu, Boqing; Zhu, Yiming

    2015-09-01

    We propose an ultrathin and flexible dual band absorber operated at terahertz frequencies based on metamaterial. The metamaterial structure consists of periodical split ring resonators with two asymmetric gaps and a metallic ground plane, separated by a thin-flexible dielectric spacer. Particularly, the dielectric spacer is a free-standing polyimide film with thickness of 25 μm, resulting in highly flexible for our absorber and making it promising for non-planar applications such as micro-bolometers and stealth aircraft. Experimental results show that the absorber has two resonant absorption frequencies (0.41 THz and 0.75 THz) with absorption rates 92.2% and 97.4%, respectively. The resonances at the absorption frequencies come from normal dipole resonance and high-order dipole resonance which is inaccessible in the symmetrical structure. Multiple reflection interference theory is used to analyze the mechanism of the absorber and the results are in good agreement with simulated and experimental results. Furthermore, the absorption properties are studied under various spacer thicknesses. This kind of metamaterial absorber is insensitive to polarization, has high absorption rates (over 90%) with wide incident angles range from 0° to 45° and the absorption rates are also above 90% when wrapping it to a curved surface.

  20. Eddy Current Flexible Probes for Complex Geometries

    Science.gov (United States)

    Gilles-Pascaud, C.; Decitre, J. M.; Vacher, F.; Fermon, C.; Pannetier, M.; Cattiaux, G.

    2006-03-01

    The inspection of materials used in aerospace, nuclear or transport industry is a critical issue for the safety of components exposed to stress or/and corrosion. The industry claims for faster, more sensitive, and more flexible techniques. Technologies based on Eddy Current (EC) flexible array probe and magnetic sensor with high sensitivity such as giant magneto-resistance (GMR) could be a good solution to detect surface-breaking flaws in complex shaped surfaces. The CEA has recently developed, with support from the French Institute for Radiological Protection and Nuclear Safety (IRSN), a flexible array probe based on micro-coils etched on Kapton. The probe's performances have been assessed for the inspection of reactor residual heat removal pipes, and for aeronautical applications within the framework of the European project VERDICT. The experimental results confirm the very good detection of narrow cracks on plane and curve shaped surfaces. This paper also describes the recent progresses concerning the application of GMR sensors to EC testing, and the results obtained for the detection of small surface breaking flaws.

  1. Identificação do dano induzido por fadiga e cura de micro trincas em compósitos cerâmicos particulados, voltados à aplicação em pavimentos flexíveis Fatigue damage induced and healing identification in particulate ceramic composites for application in flexible pavings

    Directory of Open Access Journals (Sweden)

    F. R. G. Nunes

    2009-12-01

    Full Text Available Um dos grandes defeitos ocorrentes no pavimento, ao longo de sua vida útil, é o trincamento por fadiga. Este problema, em geral, se inicia na base do revestimento asfáltico e se propaga para a sua superfície. A caracterização das misturas asfálticas, realizada comumente no Brasil, é baseada no número de ciclos que causam a ruptura no ensaio de fadiga. No entanto, tal número não é um parâmetro mecânico, podendo variar para diferentes condições de contorno. O objetivo do presente artigo é identificar parâmetros mecânicos, referentes ao trincamento por fadiga, do compósito asfáltico com agregado sintético de argila calcinada (ASAC. Para tanto, foi utilizado um modelo viscoelástico de dano contínuo, fundamentado em trabalhos de Shapery, Kim e Lee. Os resultados com o compósito estudado (ASAC mostraram que a perda de rigidez, baseada em uma variável interna de estado, pode ser um critério de fadiga; que o ensaio pode ser realizado para um nível de tensão; a cura de microtrincas durante os períodos de não solicitação da estrutura.One of the major distresses in flexible pavings, throughout its useful life, is the fatigue cracking. This problem, in general, initiates in the base of the asphalt layer and propagates for its surface. The characterization of the asphalt mixtures, carried out in Brazil, is based on the number of cycles that cause the rupture in the fatigue test. However, such number is not a mechanical parameter, varying for different boundary conditions. The objective of the present article is to identify mechanical parameters, referring fatigue cracking, of the asphalt composite with synthetic calcinated clay aggregates (SCCA. To this end, a continuum damage viscoelastic model was used based works from Shapery, Kim and Lee. The results with the composite studied (SCCA had shown: that the loss of rigidity, based on an internal state variable, can be a fatigue criterion; that the test can be carried through

  2. Aquatic plants are open flexible structures - a reply to Sukhodolov

    DEFF Research Database (Denmark)

    Sand-Jensen, K.

    2005-01-01

    flexible plant structure. Total wetted area was used as a reference area for drag because it can be measured with high accuracy and it was the most suitable measure of plant size impeding the flow and absorbing light for photosynthetic production. What is important is that it is made absolutely clear which......1. Aquatic plant stands are flexible, mesh-like open structures that undergo modification in shape and experience a cascade of declining flow velocities and micro-scale Reynolds numbers with increasing distance into the stands. It is not possible to define or measure the frontal area of this open...

  3. 23rd International Conference on Flexible Automation & Intelligent Manufacturing

    CERN Document Server

    2013-01-01

    The proceedings includes the set of revised papers from the 23rd International Conference on Flexible Automation and Intelligent Manufacturing (FAIM 2013). This conference aims to provide an international forum for the exchange of leading edge scientific knowledge and industrial experience regarding the development and integration of the various aspects of Flexible Automation and Intelligent Manufacturing Systems covering the complete life-cycle of a company’s Products and Processes. Contents will include topics such as: Product, Process and Factory Integrated Design, Manufacturing Technology and Intelligent Systems, Manufacturing Operations Management and Optimization and Manufacturing Networks and MicroFactories.

  4. Flexible organic solar cells including efficiency enhancing grating structures

    DEFF Research Database (Denmark)

    Oliveira Hansen, Roana Melina de; Liu, Yinghui; Madsen, Morten

    2013-01-01

    In this work, a new method for the fabrication of organic solar cells containing functional light-trapping nanostructures on flexible substrates is presented. Polyimide is spin-coated on silicon support substrates, enabling standard micro- and nanotechnology fabrication techniques......, such as photolithography and electron-beam lithography, besides the steps required for the bulk-heterojunction organic solar cell fabrication. After the production steps, the solar cells on polyimide are peeled off the silicon support substrates, resulting in flexible devices containing nanostructures for light absorption...

  5. ESTABILIDADE OXIDATIVA DE AMÊNDOAS DE NOZ MACADÂMIA SECAS POR MICRO-ONDAS COM AR QUENTE OXIDATIVE STABILITY OF MACADAMIA NUTS DRYED WITH HOT AIR MICROWAVES

    Directory of Open Access Journals (Sweden)

    Maria Ássima Bittar Gonçalves

    2011-04-01

    Full Text Available

    A nogueira macadâmia (Macadamia integrifolia Maiden & Betche produz amêndoas de alto valor comercial, que se destacam pelo fino sabor e qualidade de seu óleo. O objetivo deste trabalho foi estudar a estabilidade oxidativa de amêndoas secas, com aplicação de energia de micro-ondas com ar quente, em comparação ao processo de secagem convencional. As análises, realizadas no início (tempo zero, com 90 dias e 180 dias de armazenamento, avaliaram ácidos graxos livres, índice de peróxido, período de indução, composição em ácidos graxos e teor de tocoferol/tocotrienol. O teor de ácidos graxos livres (% das amêndoas de noz macadâmia variou de 0,095 (MW1 a 0,124 (MW3 e de 0,123 a 0,148 (CVL; os índices de peróxidos (meq O2 kg-1 de óleo entre 0,77 (MW2  e 2,57 (MW1 e de 1,52 a 3,29 (CVL; o período de indução (h de 16,7 (MW2 a 13,6 (MW4 e entre 11,9 e 10,6 (CVL; o teor de ?-Tocotrienol (mg 100 g-1 de 1,75 a 2,19 (MW1 e de 2,14 a 2,19 (CVL, respectivamente, para a secagem com micro-ondas e convencional. Os valores da composição em ácidos graxos não se alteraram durante o armazenamento, com os processos de secagem utilizados. O método de secagem com micro-ondas mostrou-se mais eficiente, em relação à estabilidade oxidativa das amêndoas de noz macadâmia, quando comparado ao processo de secagem convencional.

     

    The macadamia tree (Macadamia integrifolia Maiden & Betche produces a nut of highly commercial value, distinguishable from other nuts by its delicate flavour and oil quality. This study aimed to compare the oxidative stability of dried nuts, with the application of hot air microwave energy, in relation to conventional drying. The analyses were performed at the

  6. FLEXIBLE GEIGER COUNTER

    Science.gov (United States)

    Richter, H.G.; Gillespie, A.S. Jr.

    1963-11-12

    A flexible Geiger counter constructed from materials composed of vinyl chloride polymerized with plasticizers or co-polymers is presented. The counter can be made either by attaching short segments of corrugated plastic sleeving together, or by starting with a length of vacuum cleaner hose composed of the above materials. The anode is maintained substantially axial Within the sleeving or hose during tube flexing by means of polystyrene spacer disks or an easily assembled polyethylene flexible cage assembly. The cathode is a wire spiraled on the outside of the counter. The sleeving or hose is fitted with glass end-pieces or any other good insulator to maintain the anode wire taut and to admit a counting gas mixture into the counter. Having the cathode wire on the outside of the counter substantially eliminates the objectional sheath effect of prior counters and permits counting rates up to 300,000 counts per minute. (AEC)

  7. Flexible Metasurface Holograms

    CERN Document Server

    Burch, James; Chen, Xianzhong; Di Falco, Andrea

    2016-01-01

    Metasurface holograms are typically fabricated on rigid substrates. Here we experimentally demonstrate broadband, flexible, conformable, helicity multiplexed metasurface holograms operating in the visible range, offering increased potential for real life out-of-the-lab applications. Two symmetrically distributed holographic images are obtained when circularly polarized light impinges on the reflective-type metasurface positioned on non- planar targets. The two off-axis images with high fidelity are interchangeable by controlling the helicity of incident light. Our metasurface features the arrangement of spatially varying gold nanorods on a flexible, conformable epoxy resist membrane to realize a Pancharatnam- Berry phase profile. These results pave the way to practical applications including polarization manipulation, beam steering, novel lenses, and holographic displays.

  8. Flexible Laser Metal Cutting

    DEFF Research Database (Denmark)

    Villumsen, Sigurd; Jørgensen, Steffen Nordahl; Kristiansen, Morten

    2014-01-01

    This paper describes a new flexible and fast approach to laser cutting called ROBOCUT. Combined with CAD/CAM technology, laser cutting of metal provides the flexibility to perform one-of-a-kind cutting and hereby realises mass production of customised products. Today’s laser cutting techniques...... possess, despite their wide use in industry, limitations regarding speed and geometry. Research trends point towards remote laser cutting techniques which can improve speed and geometrical freedom and hereby the competitiveness of laser cutting compared to fixed-tool-based cutting technology...... such as punching. This paper presents the concepts and preliminary test results of the ROBOCUT laser cutting technology, a technology which potentially can revolutionise laser cutting....

  9. Strain Monitoring of Flexible Structures

    Science.gov (United States)

    Litteken, Douglas A.

    2017-01-01

    One of the biggest challenges facing NASA's deep space exploration goals is structural mass. A long duration transit vehicle on a journey to Mars, for example, requires a large internal volume for cargo, supplies and crew support. As with all space structures, a large pressure vessel is not enough. The vehicle also requires thermal, micro-meteoroid, and radiation protection, a navigation and control system, a propulsion system, and a power system, etc. As vehicles get larger, their associated systems also get larger and more complex. These vehicles require larger lift capacities and force the mission to become extremely costly. In order to build large volume habitable vehicles, with only minimal increases in launch volume and mass, NASA is developing lightweight structures. Lightweight structures are made from non-metallic materials including graphite composites and high strength fabrics and could provide similar or better structural capability than metals, but with significant launch volume and mass savings. Fabric structures specifically, have been worked by NASA off and on since its inception, but most notably in the 1990's with the TransHAB program. These TransHAB developed structures use a layered material approach to form a pressure vessel with integrated thermal and micro-meteoroid and orbital debris (MMOD) protection. The flexible fabrics allow the vessel to be packed in a small volume during launch and expand into a much larger volume once in orbit. NASA and Bigelow Aerospace recently installed the first human-rated inflatable module on the International Space Station (ISS), known as the Bigelow Expandable Activity Module (BEAM) in May of 2016. The module provides a similar internal volume to that of an Orbital ATK Cygnus cargo vehicle, but with a 77% launch volume savings. As lightweight structures are developed, testing methods are vital to understanding their behavior and validating analytical models. Common techniques can be applied to fabric materials

  10. Fuel flexible fuel injector

    Science.gov (United States)

    Tuthill, Richard S; Davis, Dustin W; Dai, Zhongtao

    2015-02-03

    A disclosed fuel injector provides mixing of fuel with airflow by surrounding a swirled fuel flow with first and second swirled airflows that ensures mixing prior to or upon entering the combustion chamber. Fuel tubes produce a central fuel flow along with a central airflow through a plurality of openings to generate the high velocity fuel/air mixture along the axis of the fuel injector in addition to the swirled fuel/air mixture.

  11. Flexible training under threat.

    Science.gov (United States)

    Houghton, Anita; Eaton, Jennifer

    2002-10-01

    As the number of women in medicine and the general demand for a better work-life balance rises, flexible training is an increasingly important mechanism for maintaining the medical workforce. The new pay deal, together with entrenched cultural attitudes, are potential threats. Ways forward include more substantive part-time posts, more part-time opportunities at consultant level, and using positive experiences as a way of tackling attitudes in the less accepting specialties.

  12. Flexible Land Administration

    DEFF Research Database (Denmark)

    Enemark, Stig

    2014-01-01

    Security of tenure is widely considered to be the missing piece of the puzzle when it comes to eradication of poverty. And, as explained in the previous issue of Geoinformatics, the European Union is now placing land rights at the heart of EU development policy. This article presents a way forwar...... in terms of building flexible and "fit-for-purpose" land administration systems in developing countries. This will ensure security of tenure for all and sustainable management of the use of land....

  13. More flexibility for DESY

    CERN Multimedia

    2003-01-01

    In the future, budgeting at DESY will be more efficient. The 16 associated research centers are to be granted a wider margin in matters of finance and human resources. The Budget Committee of the German Bundestag has agreed to abstain from mandatory staff appointments. The current pre-determined "job pyramid" will be replaced by a more flexible mechanism, so that the conclusion of fixed labor contracts can more closely follow the needs of research (1 page).

  14. Industrial Fuel Flexibility Workshop

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2006-09-01

    On September 28, 2006, in Washington, DC, ITP and Booz Allen Hamilton conducted a fuel flexibility workshop with attendance from various stakeholder groups. Workshop participants included representatives from the petrochemical, refining, food and beverage, steel and metals, pulp and paper, cement and glass manufacturing industries; as well as representatives from industrial boiler manufacturers, technology providers, energy and waste service providers, the federal government and national laboratories, and developers and financiers.

  15. Flexible Land Administration

    DEFF Research Database (Denmark)

    Enemark, Stig

    2014-01-01

    Security of tenure is widely considered to be the missing piece of the puzzle when it comes to eradication of poverty. And, as explained in the previous issue of Geoinformatics, the European Union is now placing land rights at the heart of EU development policy. This article presents a way forwar...... in terms of building flexible and "fit-for-purpose" land administration systems in developing countries. This will ensure security of tenure for all and sustainable management of the use of land....

  16. Flexible Data Link

    Science.gov (United States)

    2015-04-01

    reconfiguring the waveform characteristics (on-the-fly) based on the engagement environment. Therefore, flexibility was the highest priority in the design of...the aircraft to a ground antenna . Utilizing the threshold system requirements (100 km range), we calculate the multipath of the aircraft as it...approaches the ground antenna . Figure 3: Multipath scenario #1 The calculation of the reflected path (denoted as A + C in Figure 3) is found through the

  17. Micro club

    CERN Multimedia

    Micro club

    2014-01-01

    Opération NEMO   Pour finir en beauté les activités spéciales que le CMC a réalisé pendant cette année 2014, pour commémorer le 60ème anniversaire du CERN, et le 30ème du Micro Club, l’ Opération NEMO aura cette année un caractère très particulier. Nous allons proposer 6 fabricants de premier ordre qui offriront chacun deux ou trois produits à des prix exceptionnels. L’opération débute le lundi 17 novembre 2014. Elle se poursuivra  jusqu’au samedi 6 décembre inclus. Les délais de livraison seront de deux à trois semaines, selon les fabricants. Donc les commandes faites la dernière semaine, du 1 au 6 décembre, risquent d’arriver qu'au début du mois de janvier 2015. Liste de fabricants part...

  18. Micro club

    CERN Multimedia

    Micro Club

    2014-01-01

    Jeudi 18 septembre 2014 à 18h30 au Bât. 567 R-029 Le CERN MICRO CLUB organise un Atelier sur la sécurité informatique. La Cyber-sécurité : Ce qui se passe vraiment, comment ne pas en être victime ! Orateur : Sebastian Lopienski Adjoint au Computer Security Officer du Département IT. Sujet : Cet exposé vous présentera les modes de sécurité actuels et les problèmes touchants les applications logicielles des ordinateurs, les réseaux ainsi que leurs utilisateurs. Cela inclus des informations sur les nouveaux types de vulnérabilité, les vecteurs d'attaque récents et une vue d'ensemble sur le monde de la cyber-sécurité en 2014. Biographie : Sebastian Lopienski travaille au CERN depuis 2001. Il est actuellement adjoint au Computer Security Officer et s'occupe de la protection de...

  19. Designing structural supply chain flexibility

    NARCIS (Netherlands)

    Mulinski, Ksawery Jan

    2012-01-01

    In a continuously changing business environment the role of supply chain flexibility is constantly increasing. A flexible supply chain can ensure survival in quickly changing market conditions as well as enable sustainable growth. This thesis explores the topic of supply chain flexibility with focus

  20. Flexible Scheduling: Making the Transition

    Science.gov (United States)

    Creighton, Peggy Milam

    2008-01-01

    Citing literature that supports the benefits of flexible scheduling on student achievement, the author exhorts readers to campaign for flexible scheduling in their library media centers. She suggests tips drawn from the work of Graziano (2002), McGregor (2006) and Stripling (1997) for making a smooth transition from fixed to flexible scheduling:…

  1. Designing structural supply chain flexibility

    NARCIS (Netherlands)

    Mulinski, Ksawery Jan

    2012-01-01

    In a continuously changing business environment the role of supply chain flexibility is constantly increasing. A flexible supply chain can ensure survival in quickly changing market conditions as well as enable sustainable growth. This thesis explores the topic of supply chain flexibility with focus

  2. Hardware Requirements for Helicopter Air-to-Air Weapons in the 1980s

    Science.gov (United States)

    1978-06-09

    flexibility to be used against both air- to-air and air-to-surface targets. The XM14c ( Figura 0) is a light weight 30-mm automatic gun capable of a... Publica - tion, 14 November 1977. 7!-L . ... . . . .. .. .. lobj U.S. Army Command and General Staff College, Profession of Am Course 9000 (PY A74-73

  3. Variable volume combustor with an air bypass system

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Thomas Edward; Ziminsky, Willy Steve; Ostebee, Heath Michael; Keener, Christopher Paul

    2017-02-07

    The present application provides a combustor for use with flow of fuel and a flow of air in a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles positioned within a liner and an air bypass system position about the liner. The air bypass system variably allows a bypass portion of the flow of air to bypass the micro-mixer fuel nozzles.

  4. Earthworm-like micro robot based on electromagnetic driver

    Institute of Scientific and Technical Information of China (English)

    Wang Kundong; Yan Guozheng

    2007-01-01

    According to the principle of bionics, a prototype of the earthworm-like micro robot was developed and manufactured for entering the small tube. Based on the process of the action and mechanics analysis, the controller was designed. This micro robot with 6mm diameter was driven directly by three electromagnetic linear drivers. Mobile cells were Joined with two degree-of-freedom joint and the whole body Was flexible and soft. The driving force reached 10.8g in normal working condition. The direction of movement and the angle of imaging can be controlled by the shape memory alloy (SMA). The driving force, velocity and movement of micro robot in flexural tube were tested through experiments, which indicated that the driving force was in proportion to the current, and the velocity reached a maximum in certain range of frequency, and the micro robot could move in the thin tube flexibly.

  5. Flexible metamaterial absorbers with multi-band infrared response

    Science.gov (United States)

    Dayal, Govind; Ramakrishna, S. Anantha

    2015-01-01

    A flexible metamaterial with a tri-layer metal-dielectric-metal structure is fabricated by combining Excimer laser micromachining of a polyimide sheet and oblique angle physical vapour deposition methods. Excimer laser micromachining is used to generate an array of micro-disks on the flexible polymer sheet followed by physical vapour deposition at normal incidence to produce continuous metal and dielectric layers while oblique angle deposition of metal vapour is used to finally form discrete oblate ellipsoids on top of the micro-disks. The fabricated metamaterial shows multi-band metamaterial absorption exceeding 90% simultaneously over infrared bands centred at 3 µm, 5 µm, and 13.85 µm. The multi-band absorption arises due to multipole resonances of the disk structure and is accurately modelled by electromagnetic simulation as well. A theoretical model of a perfect absorber as an array of optimally impedance matched antennas is also presented.

  6. Flexible, fpga-based electronics for modular robots

    DEFF Research Database (Denmark)

    Brandt, David; Larsen, Jørgen Christian; Christensen, David Johan

    2008-01-01

    In this paper we introduce electronics for the ATRON self-reconfigurable robot based on field programmable gate arrays (FPGAs). The immediate advantage of using FPGAs is that some of the module’s electronics can be moved into the FPGA, thereby the number of components can be reduced. In the case...... consumption compared to micro-controllers. However, overall FPGAs make the electronics of modular robots more flexible and therefore may make them more suitable for real applications. AB - In this paper we introduce electronics for the ATRON self-reconfigurable robot based on field programmable gate arrays...... the electronics for specific tasks. The disadvantages of an FPGA-based design include the cost of FPGAs, the extra layer of complexity in programming, and a limited increase in power consumption compared to micro-controllers. However, overall FPGAs make the electronics of modular robots more flexible...

  7. Simulation approach towards energy flexible manufacturing systems

    CERN Document Server

    Beier, Jan

    2017-01-01

    This authored monograph provides in-depth analysis and methods for aligning electricity demand of manufacturing systems to VRE supply. The book broaches both long-term system changes and real-time manufacturing execution and control, and the author presents a concept with different options for improved energy flexibility including battery, compressed air and embodied energy storage. The reader will also find a detailed application procedure as well as an implementation into a simulation prototype software. The book concludes with two case studies. The target audience primarily comprises research experts in the field of green manufacturing systems. .

  8. Air Pollution

    Science.gov (United States)

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  9. Measuring and Comparing Energy Flexibilities

    DEFF Research Database (Denmark)

    Valsomatzis, Emmanouil; Hose, Katja; Pedersen, Torben Bach

    2015-01-01

    Flexibility in energy supply and demand becomes more and more important with increasing Renewable Energy Sources (RES) production and the emergence of the Smart Grid. So-called prosumers, i.e., entities that produce and/or consume energy, can offer their inherent flexibilities through so......-called demand response and thus help stabilize the energy markets. Thus, prosumer flexibility becomes valuable and the ongoing Danish project TotalFlex [1] explores the use of prosumer flexibility in the energy market using the concept of a flex-offer [2], which captures energy flexibilities in time and...... induced by time and amount individually, and by their com- bination. To this end, we introduce several flexibility measures that take into account the combined effect of time and energy on flex-offer flexibility and discuss their respective pros and cons through a number of realistic examples....

  10. Novel MAV Air Data System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The development of Micro Air Vehicles (MAVs) has received considerable attention in recent years for both military and civilian uses. MAVs typically suffer from...

  11. Flexible Volumetric Structure

    Science.gov (United States)

    Cagle, Christopher M. (Inventor); Schlecht, Robin W. (Inventor)

    2014-01-01

    A flexible volumetric structure has a first spring that defines a three-dimensional volume and includes a serpentine structure elongatable and compressible along a length thereof. A second spring is coupled to at least one outboard edge region of the first spring. The second spring is a sheet-like structure capable of elongation along an in-plane dimension thereof. The second spring is oriented such that its in-plane dimension is aligned with the length of the first spring's serpentine structure.

  12. Flexible composite radiation detector

    Science.gov (United States)

    Cooke, D. Wayne; Bennett, Bryan L.; Muenchausen, Ross E.; Wrobleski, Debra A.; Orler, Edward B.

    2006-12-05

    A flexible composite scintillator was prepared by mixing fast, bright, dense rare-earth doped powdered oxyorthosilicate (such as LSO:Ce, LSO:Sm, and GSO:Ce) scintillator with a polymer binder. The binder is transparent to the scintillator emission. The composite is seamless and can be made large and in a wide variety of shapes. Importantly, the composite can be tailored to emit light in a spectral region that matches the optimum response of photomultipliers (about 400 nanometers) or photodiodes (about 600 nanometers), which maximizes the overall detector efficiency.

  13. Composite Flexible Blanket Insulation

    Science.gov (United States)

    Kourtides, Demetrius A. (Inventor); Pitts, William C. (Inventor); Goldstein, Howard E. (Inventor); Sawko, Paul M. (Inventor)

    1991-01-01

    Composite flexible multilayer insulation systems (MLI) were evaluated for thermal performance and compared with the currently used fibrous silica (baseline) insulation system. The systems described are multilayer insulations consisting of alternating layers of metal foil and scrim ceramic cloth or vacuum metallized polymeric films quilted together using ceramic thread. A silicon carbide thread for use in the quilting and the method of making it are also described. These systems are useful in providing lightweight insulation for a variety of uses, particularly on the surface of aerospace vehicles subject to very high temperatures during flight.

  14. Flexible plasma linear antenna

    Science.gov (United States)

    Zhao, Jiansen; Wang, Shengzheng; Wu, Huafeng; Liu, Yue; Chang, Yongmeng; Chen, Xinqiang

    2017-02-01

    In this work, we introduce a type of plasma antenna that was fabricated using flexible materials and excited using a 5-20 kHz alternating current (ac) power supply. The results showed that the antenna characteristics, including the impedance, the reflection coefficient (S11), the radiation pattern, and the gain, can be controlled rapidly and easily by varying both the discharge parameters and the antenna shapes. The scope for reconfiguration is greatly enhanced when the antenna shape is changed from a monopole to a helix configuration. Additionally, the antenna polarization can also be adjusted by varying the antenna shapes.

  15. Flexible aerogel composite for mechanical stability and process of fabrication

    Science.gov (United States)

    Coronado, Paul R.; Poco, John F.

    1999-01-01

    A flexible aerogel and process of fabrication. An aerogel solution is mixed with fibers in a mold and allowed to gel. The gel is then processed by supercritical extraction, or by air drying, to produce a flexible aerogel formed to the shape of the mold. The flexible aerogel has excellent thermal and acoustic properties, and can be utilized in numerous applications, such as for energy absorption, insulation (temperature and acoustic), to meet the contours of aircraft shapes, and where space is limited since an inch of aerogel is a 4-5 times better insulator than an inch of fiberglass. The flexible aerogel may be of an inorganic (silica) type or an organic (carbon) type, but containing fibers, such as glass or carbon fibers.

  16. MICRO AUTO GASIFICATION SYSTEM: EMISSIONS CHARACTERIZATION

    Science.gov (United States)

    A compact, CONEX-housed waste to energy unit, Micro Auto Gasification System (MAGS), was characterized for air emissions from burning of military waste types. The MAGS unit is a dual chamber gasifier with a secondary diesel-fired combustor. Eight tests were conducted with multipl...

  17. Self-assembly micro optical filter

    Science.gov (United States)

    Zhang, Ping (Cerina); Le, Kevin; Malalur-Nagaraja-Rao, Smitha; Hsu, Lun-Chen; Chiao, J.-C.

    2006-01-01

    Optical communication and sensor industry face critical challenges in manufacturing for system integration. Due to the assembly complexity and integration platform variety, micro optical components require costly alignment and assembly procedures, in which many required manual efforts. Consequently, self-assembly device architectures have become a great interest and could provide major advantages over the conventional optical devices. In this paper, we discussed a self-assembly integration platform for micro optical components. To demonstrate the adaptability and flexibility of the proposed optical device architectures, we chose a commercially available MEMS fabrication foundry service - MUMPs (Multi-User MEMS Process). In this work, polysilicon layers of MUMPS are used as the 3-D structural material for construction of micro component framework and actuators. However, because the polysilicon has high absorption in the visible and near infrared wavelength ranges, it is not suitable for optical interaction. To demonstrate the required optical performance, hybrid integration of materials was proposed and implemented. Organic compound materials were applied on the silicon-based framework to form the required optical interfaces. Organic compounds provide good optical transparency, flexibility to form filters or lens and inexpensive manufacturing procedures. In this paper, we have demonstrated a micro optical filter integrated with self-assembly structures. We will discuss the self-assembly mechanism, optical filter designs, fabrication issues and results.

  18. Efficient industrial burner control of a flexible burner management system; Effiziente industrielle Brennertechnik durch Einsatz flexibler Feuerungsautomaten

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Ulrich; Saenger, Peter [Siemens AG, Rastatt (Germany)

    2012-02-15

    Compactness and flexibility of a burner control system is a very important issue. With a few types a wide range in different industrial applications should be covered. This paper presents different applications of a new burner control system: heating of cooling lines in glass industry, steam generation and air heating for a pistachio roastery and in grain dryers. (orig.)

  19. Method and apparatus for air-coupled transducer

    Science.gov (United States)

    Song, Junho (Inventor); Chimenti, Dale E. (Inventor)

    2010-01-01

    An air-coupled transducer includes a ultrasonic transducer body having a radiation end with a backing fixture at the radiation end. There is a flexible backplate conformingly fit to the backing fixture and a thin membrane (preferably a metallized polymer) conformingly fit to the flexible backplate. In one embodiment, the backing fixture is spherically curved and the flexible backplate is spherically curved. The flexible backplate is preferably patterned with pits or depressions.

  20. Breathable and Wearable Energy Storage Based on Highly Flexible Paper Electrodes.

    Science.gov (United States)

    Dong, Liubing; Xu, Chengjun; Li, Yang; Pan, Zhengze; Liang, Gemeng; Zhou, Enlou; Kang, Feiyu; Yang, Quan-Hong

    2016-11-01

    Breathable and wearable energy storage is achieved based on an innovative design solution. Carbon nanotube/MnO2 -decorated air-laid paper electrodes, with outstanding flexibility and good electrochemical performances, are prepared. They are then assembled into solid-state supercapacitors. By making through-holes on the supercapacitors, breathable and flexible supercapacitors are successfully fabricated.

  1. 40 CFR 63.1293 - Standards for slabstock flexible polyurethane foam production.

    Science.gov (United States)

    2010-07-01

    ... polyurethane foam production. 63.1293 Section 63.1293 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1293 Standards for slabstock flexible polyurethane foam production. Each owner or operator of...

  2. 40 CFR 63.1300 - Standards for molded flexible polyurethane foam production.

    Science.gov (United States)

    2010-07-01

    ... polyurethane foam production. 63.1300 Section 63.1300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1300 Standards for molded flexible polyurethane foam production. Each owner or operator of a...

  3. A Micro-PIV Study of the Pulsed Micro-Flows Driven by an Insulin Pump

    Science.gov (United States)

    Wang, Bing; Demuren, Ayodeji; Gyuricsko, Eric; Hu, Hui

    2009-11-01

    In recent years, there is a surge in the popularity of using insulin pump or continuous subcutaneous insulin infusion therapy, as opposed to multiple daily injections by insulin syringe or an insulin pen. Some case studies have suggested that insulin delivery failure may be caused by precipitation of insulin within the infusion set. Speculation also exists that the flow of insulin through an insulin infusion set may be reduced or inhibited by air bubbles entrained into the micro-sized tubing system since there are chances that air be introduced into the insulin reservoir during the filling process. In the present study, a microscopic Particle Image Velocimtry (micro-PIV) system was used to characterize the transient behavior of the pulsed micro-flows inside the micro-sized tubing system of an insulin infusion set with insulin pump operating in basal mode (i.e., pulsed insulin pumping). The effects of the air bubbles entrained into the micro-sized tubing system on the insulin delivery process were assessed based on the micro-PIV measurements.

  4. Air Force Power Requirements

    Science.gov (United States)

    2006-01-24

    2 Outline • Our Recent Heritage – MEA • Our Plan – HiPAC • HiPAC Technologies • Summary Powering the United States Air Force NASA AI R FO RC E NA VY...Aircraft i l i Munitions / UAV i i / Micro-Mini Platforms i i i l HiPAC Technical Program Areas • High Temperature Power System Components • High

  5. Flexible organic solar cells including efficiency enhancing grating structures

    DEFF Research Database (Denmark)

    Oliveira Hansen, Roana Melina de; Liu, Yinghui; Madsen, Morten

    2013-01-01

    enhancement. Since the solar cells avoid using brittle electrodes, the performance of the flexible devices is not affected by the peeling process. We have investigated three different nanostructured grating designs and conclude that gratings with a 500 nm pitch distance have the highest light......In this work, a new method for the fabrication of organic solar cells containing functional light-trapping nanostructures on flexible substrates is presented. Polyimide is spin-coated on silicon support substrates, enabling standard micro- and nanotechnology fabrication techniques......, such as photolithography and electron-beam lithography, besides the steps required for the bulk-heterojunction organic solar cell fabrication. After the production steps, the solar cells on polyimide are peeled off the silicon support substrates, resulting in flexible devices containing nanostructures for light absorption...

  6. Asymmetric Flexible Supercapacitor Stack

    Directory of Open Access Journals (Sweden)

    Leela Mohana Reddy A

    2008-01-01

    Full Text Available AbstractElectrical double layer supercapacitor is very significant in the field of electrical energy storage which can be the solution for the current revolution in the electronic devices like mobile phones, camera flashes which needs flexible and miniaturized energy storage device with all non-aqueous components. The multiwalled carbon nanotubes (MWNTs have been synthesized by catalytic chemical vapor deposition technique over hydrogen decrepitated Mischmetal (Mm based AB3alloy hydride. The polymer dispersed MWNTs have been obtained by insitu polymerization and the metal oxide/MWNTs were synthesized by sol-gel method. Morphological characterizations of polymer dispersed MWNTs have been carried out using scanning electron microscopy (SEM, transmission electron microscopy (TEM and HRTEM. An assymetric double supercapacitor stack has been fabricated using polymer/MWNTs and metal oxide/MWNTs coated over flexible carbon fabric as electrodes and nafion®membrane as a solid electrolyte. Electrochemical performance of the supercapacitor stack has been investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.

  7. Novel metamaterial based antennas for flexible wireless systems

    Science.gov (United States)

    Khaleel, Haider Raad

    Recent years have witnessed a great deal of interest from both academia and industry in the field of flexible electronic systems. This research topic tops the pyramid of research priorities requested by many national research agencies. Consistently, flexible electronic systems require the integration of flexible antennas operating in specific frequency bands to provide wireless connectivity which is highly demanded by today's information oriented society. On the other hand, metamaterials have become very popular in the design of contemporary antenna and microwave devices due to their wide range of applications derived from their unique properties which significantly enhances the performance of antennas and RF systems. Accordingly, the integration of metamaterial structures within flexible wireless systems is very beneficial in this growing field of research. A systematic approach to the analysis and design of flexible and conformal antennas and metamaterials is ultimately needed. The research reported in this thesis focuses on developing flexible low profile antennas and metamaterial structures in addition to characterizing their performance when integrated within flexible wireless systems. Three flexible, compact, and extremely low profile (50.8 microm) antennas intended for WLAN, Bluetooth and Ultra Wide Band (UWB) applications are presented. Next, a novel miniaturized Artificial Magnetic Conductor (AMC) and a new technique to enhance the bandwidth of micro-Negative (MNG) metamaterial are reported. Furthermore, the effect of bending on the AMC and MNG metamaterial is investigated in this thesis for the first time. Finally, the findings of this research are utilized in practical applications with specific design constraints including mutual coupling reduction between radiating elements in antenna arrays and MIMO systems and Specific Absorption Rate (SAR) reduction in telemedicine systems.

  8. The Flexibility Hypothesis of Healing.

    Science.gov (United States)

    Hinton, Devon E; Kirmayer, Laurence J

    2017-03-01

    Theories of healing have attempted to identify general mechanisms that may work across different modalities. These include altering expectations, remoralization, and instilling hope. In this paper, we argue that many forms of healing and psychotherapy may work by inducing positive psychological states marked by flexibility or an enhanced ability to shift cognitive sets. Healing practices may induce these states of cognitive and emotional flexibility through specific symbolic interventions we term "flexibility primers" that can include images, metaphors, music, and other media. The flexibility hypothesis suggests that cognitive and emotional flexibility is represented, elicited, and enacted through multiple modalities in healing rituals. Identifying psychological processes and cultural forms that evoke and support cognitive and emotional flexibility provides a way to understand the cultural specificity and potential efficacy of particular healing practices and can guide the design of interventions that promote resilience and well-being.

  9. Automation of 3D micro object handling process

    DEFF Research Database (Denmark)

    Gegeckaite, Asta; Hansen, Hans Nørgaard

    2007-01-01

    Most of the micro objects in industrial production are handled with manual labour or in semiautomatic stations. Manual labour usually makes handling and assembly operations highly flexible, but slow, relatively imprecise and expensive. Handling of 3D micro objects poses special challenges due...... to the small absolute scale. In this article, the results of the pick-and-place operations of three different 3D micro objects were investigated. This study shows that depending on the correct gripping tool design as well as handling and assembly scenarios, a high success rate of up to 99% repeatability can...

  10. The MicroMAS CubeSat Mission

    Science.gov (United States)

    Cahoy, K.; Blackwell, W. J.; Allen, G.; Bury, M.; Efromson, R.; Galbraith, C.; Hancock, T.; Leslie, V.; Osaretin, I.; Retherford, L.; Scarito, M.; Shields, M.; Toher, D.; Wight, K.; Miller, D.; Marinan, A.; Paek, S.; Peters, E.; Schmidt, F. H.; Alvisio, B.; Wise, E.; Masterson, R.; Franzim Miranda, D.; Crail, C.; Kingsbury, R.; Souffrant, A.; Orrego, L.; Eslinger, G.; Nicholas, A.; Pong, C.

    2012-12-01

    The recently published Midterm Assessment of NASA's Implementation of the Decadal Survey finds that, "The nation's Earth observing system is beginning a rapid decline in capability as long-running missions end and key new missions are delayed, lost, or canceled. The projected loss of observing capability could have significant adverse consequences for science and society." In this presentation, we explore low-cost, mission-flexible, and rapidly deployable spaceborne sensors that can meet stringent performance requirements pervading the NASA Earth Science measurement programs, including especially the recommended NRC Decadal Survey missions. New technologies have enabled a novel approach toward this science observational goal, and in this paper we describe recent technology develop efforts to address the challenges above through the use of CubeSat radiometers. The Micro-sized Microwave Atmospheric Satellite (MicroMAS) is a 3U cubesat (30x10x10 cm, ~4kg) hosting a passive microwave spectrometer operating near the 118.75-GHz oxygen absorption line. The focus of the first MicroMAS mission (hereafter, MicroMAS-1) is to observe convective thunderstorms, tropical cyclones, and hurricanes from a near-equatorial orbit at approximately 500-km altitude. A MicroMAS flight unit is currently being developed in anticipation of a 2014 launch to be provided by NASA. A parabolic reflector is mechanically rotated as the spacecraft orbits the earth, thus directing a cross-track scanned beam with FWHM beamwidth of 2.4-degrees, yielding an approximately 25-km diameter footprint from a nominal altitude of 500 km. Radiometric calibration is carried out using observations of cold space, the earth's limb, and an internal noise diode that is weakly coupled through the RF front-end electronics. A key technology feature is the development of an ultra-compact intermediate frequency processor module for channelization, detection, and A-to-D conversion. The antenna system and RF front

  11. Flexible cultural repertoires

    DEFF Research Database (Denmark)

    Lindegaard, Marie Rosenkrantz

    2016-01-01

    Despite extensive studies of street culture and the risks of offending and victimization in urban marginalized areas, little is known about the role of cultural repertoires for variation in victimization risks among young men not involved in crime. Based on two ethnographic studies, conducted...... varying cultural repertoires, in particularly heterogeneous flexible repertoires, influence offending and victimization patterns among young men in high-risk settings....... independently of the authors in neighbouring township areas of Cape Town, we offer insights into patterns of victimization among young men not involved in crime who live and attend school in the townships. Young men who perform decent cultural repertoires are highly exposed to victimization due to their moral...

  12. Conformational flexibility of aspartame.

    Science.gov (United States)

    Toniolo, Claudio; Temussi, Pierandrea

    2016-05-01

    L-Aspartyl-L-phenylalanine methyl ester, better known as aspartame, is not only one of the most used artificial sweeteners, but also a very interesting molecule with respect to the correlation between molecular structure and taste. The extreme conformational flexibility of this dipeptide posed a huge difficulty when researchers tried to use it as a lead compound to design new sweeteners. In particular, it was difficult to take advantage of its molecular model as a mold to infer the shape of the, then unknown, active site of the sweet taste receptor. Here, we follow the story of the 3D structural aspects of aspartame from early conformational studies to recent docking into homology models of the receptor. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 376-384, 2016.

  13. Flexible microdevices based on carbon nanotubes

    Science.gov (United States)

    Allen, Ashante'; Cannon, Andrew; Lee, Jungchul; King, William P.; Graham, Samuel

    2006-12-01

    This work reports the fabrication and testing of flexible carbon nanotube microdevices made using hot embossing material transfer. Both micro-plasma and photodetector devices were made using as-grown unpurified multi-wall carbon nanotubes printed on PMMA substrates. Optical detectors were fabricated by attaching metal wires and monitoring the resistance as a function of light exposure. The electrical resistance of the nanotubes showed a strong sensitivity to light exposure which was also enhanced by heating the devices. While such processes in MWCNTs are not fully understood, the addition of thermal energy is believed to generate additional free charge carriers in the nanotubes. The plasma-generating microdevices consisted of a thin layer of thermoplastic polymer having the CNT electrode on one side and a metal electrode on the reverse side. The devices were electrically tested under atmospheric conditions with 0.01-1 kV ac and at 2.5 kHz, with the plasma igniting near 0.7 kV. The fabrication of these flexible organic devices demonstrates the ability to pattern useful carbon nanotube microdevices in low-cost thermoplastic polymers.

  14. Influence of intra-molecular flexibility on the elastic property of double-stranded DNA film on a substrate

    Science.gov (United States)

    Wu, Jun-Zheng; Meng, Wei-Lie; Tang, Heng-Song; Zhang, Neng-Hui

    2017-05-01

    DNA film self-assembled or nanografted on a substrate, as a kind of soft matter, consists of fixed DNA chains endowed with negative charges and an aqueous solution full of cations, anions and water molecules. Their thermal/electrical/mechanical properties are closely related to the complex biodetection signals in nano-/micro-scale biosensors and other new genome technologies. This makes it important to properly characterize these properties. In this paper, the effect of flexible micro-scale configurations on the elastic moduli of DNA films is investigated. First, illuminated by Qiu’s sphere model, an alternative bead-chain model in terms of the Yukawa potential is presented for flexible intra-DNA configurations to describe interactions between DNA fragments. The effective charges of coarse-grained DNA beads could be derived, in which the empirical parameters are identified by curve fitting with Qiu’s experimental data. Second, the updated mesoscopic bead-chain model and the thought experiment of a continuum compression bar are used to compare the elastic moduli of double-stranded DNA (dsDNA) films prepared by self-assembling and nanografting techniques. Configurational sampling is achieved via Monte Carlo simulation. Our predictions quantitatively or qualitatively agree well with the relevant experiments on the effective charge of dsDNA from low to moderate monovalent counterion concentration, immobilization deflection of single-stranded DNA (ssDNA) or dsDNA microcantilever with the variation of salt concentration, and elastic modulus of ssDNA film in the air. The results reveal that different solution environment stimulates the diverse mechanical properties of dsDNA film on a substrate, and the end effect (i.e. terminal group effect) makes self-assembling dsDNA film stiffer in the sense of the same average packing density.

  15. Organic Field-Effect Transistors Based on a Liquid-Crystalline Polymeric Semiconductor using SU-8 Gate Dielectrics onFlexible Substrates

    Directory of Open Access Journals (Sweden)

    Kornelius Tetzner

    2014-10-01

    Full Text Available In this work, the insulating properties of poly(4-vinylphenol (PVP and SU-8 (MicroChem, Westborough, MA, USA dielectrics are analyzed and compared with each other. We further investigate the performance behavior of organic field-effect transistors based on a semiconducting liquid-crystal polymer (LCP using both dielectric materials and evaluate the results regarding the processability. Due to the lower process temperature needed for the SU-8 deposition, the realization of organic transistors on flexible substrates is demonstrated showing comparable charge carrier mobilities to devices using PVP on glass. In addition, a µ-dispensing procedure of the LCP on SU-8 is presented, improving the switching behavior of the organic transistors, and the promising stability data of the SU-8/LCP stack are verified after storing the structures for 60 days in ambient air showing negligible irreversible degradation of the organic semiconductor.

  16. Flexible pipe crawling device having articulated two axis coupling

    Science.gov (United States)

    Zollinger, William T.

    1994-01-01

    An apparatus for moving through the linear and non-linear segments of piping systems. The apparatus comprises a front leg assembly, a rear leg assembly, a mechanism for extension and retraction of the front and rear leg assembles with respect to each other, such as an air cylinder, and a pivoting joint. One end of the flexible joint attaches to the front leg assembly and the other end to the air cylinder, which is also connected to the rear leg assembly. The air cylinder allows the front and rear leg assemblies to progress through a pipe in "inchworm" fashion, while the joint provides the flexibility necessary for the pipe crawler to negotiate non-linear piping segments. The flexible connecting joint is coupled with a spring-force suspension system that urges alignment of the front and rear leg assemblies with respect to each other. The joint and suspension system cooperate to provide a firm yet flexible connection between the front and rear leg assemblies to allow the pivoting of one with respect to the other while moving around a non-linear pipe segment, but restoring proper alignment coming out of the pipe bend.

  17. Analysis of Trajectory Flexibility Preservation Impact on Traffic Complexity

    Science.gov (United States)

    Idris, Husni; El-Wakil, Tarek; Wing, David J.

    2009-01-01

    The growing demand for air travel is increasing the need for mitigation of air traffic congestion and complexity problems, which are already at high levels. At the same time new information and automation technologies are enabling the distribution of tasks and decisions from the service providers to the users of the air traffic system, with potential capacity and cost benefits. This distribution of tasks and decisions raises the concern that independent user actions will decrease the predictability and increase the complexity of the traffic system, hence inhibiting and possibly reversing any potential benefits. In answer to this concern, the authors proposed the introduction of decision-making metrics for preserving user trajectory flexibility. The hypothesis is that such metrics will make user actions naturally mitigate traffic complexity. In this paper, the impact of using these metrics on traffic complexity is investigated. The scenarios analyzed include aircraft in en route airspace with each aircraft meeting a required time of arrival in a one-hour time horizon while mitigating the risk of loss of separation with the other aircraft, thus preserving its trajectory flexibility. The experiments showed promising results in that the individual trajectory flexibility preservation induced self-separation and self-organization effects in the overall traffic situation. The effects were quantified using traffic complexity metrics, namely dynamic density indicators, which indicated that using the flexibility metrics reduced aircraft density and the potential of loss of separation.

  18. A study on magnetic abrasive deburring of dual micro pattern

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Dong Hyun; Kwak, Jae Seob [Dept. of Mechanical Engineering, Pukyong National University, Busan (Korea, Republic of)

    2016-12-15

    Studies on dual micro pattern are not established because of difficulty of its fabrication and deburring technology. In this investigation, a dual micro pattern which consists of a net pattern and a lenticular pattern was fabricated on a cylindrical workpiece by turning process. Magnetic abrasive deburring (MAD) was proposed as a deburring process in this study. Burr height defined by difference of its height and theoretical pattern height was measured as about 1 μm. It is one of the non-traditional machining methods utilizing flexible tool which consists of ferrous particle and abrasive powder. Hence, the aim of this investigation is to remove generated burr on the dual micro pattern. Burr at the dual micro pattern was removed through MAD, and a prediction equation of machined pattern height was derived. A deburring condition was optimized and verified by experiments. As a result, it was confirmed that dual micro pattern which has high shape accuracy was fabricated using MAD.

  19. Flexible, Smart, and Lethal: Adapting US SEAD Doctrine to Changing Threats

    Science.gov (United States)

    2016-01-01

    into the format and design of the article. To gain total air supremacy in the modern age, air forces must not only render the enemy’s air force...40R6 / S-400 Triumf Self Propelled Air Defence System / SA-21,” Technical Report APA -TR-2009-0503, Air Power Australia, 27 January 2014, http...www.ausairpower .net/ APA -S-400-Triumf.html. 18. Ibid. Summer 2016 | 77 Flexible, Smart, and Lethal 19. JP 3-01, Countering Air and Missile Threats, IV-13

  20. Automated assembly of micro mechanical parts in a Microfactory setup

    DEFF Research Database (Denmark)

    Eriksson, Torbjörn Gerhard; Hansen, Hans Nørgaard; Gegeckaite, Asta

    2006-01-01

    Many micro products in use today are manufactured using semi-automatic assembly. Handling, assembly and transport of the parts are especially labour intense processes. Automation of these processes holds a large potential, especially if flexible, modular microfactories can be developed. This pape...

  1. Strain response of stretchable micro-electrodes: Controlling sensitivity with serpentine designs and encapsulation

    Energy Technology Data Exchange (ETDEWEB)

    Gutruf, Philipp; Walia, Sumeet; Nur Ali, Md; Sriram, Sharath, E-mail: sharath.sriram@gmail.com, E-mail: madhu.bhaskaran@gmail.com; Bhaskaran, Madhu, E-mail: sharath.sriram@gmail.com, E-mail: madhu.bhaskaran@gmail.com [Functional Materials and Microsystems Research Group, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria (Australia)

    2014-01-13

    The functionality of flexible electronics relies on stable performance of thin film micro-electrodes. This letter investigates the behavior of gold thin films on polyimide, a prevalent combination in flexible devices. The dynamic behavior of gold micro-electrodes has been studied by subjecting them to stress while monitoring their resistance in situ. The shape of the electrodes was systematically varied to examine resistive strain sensitivity, while an additional encapsulation was applied to characterize multilayer behavior. The realized designs show remarkable tolerance to repetitive strain, demonstrating that curvature and encapsulation are excellent approaches for minimizing resistive strain sensitivity to enable durable flexible electronics.

  2. Pressure sensing by flexible, organic, field effect transistors

    Science.gov (United States)

    Manunza, I.; Sulis, A.; Bonfiglio, A.

    2006-10-01

    A mechanical sensor based on a pentacene field effect transistor has been fabricated. The pressure dependence of the output current has been investigated by applying a mechanical stimulus by means of a pressurized air flow. Experimental results show a reversible current dependence on pressure. Data analysis suggests that variations of threshold voltage, mobility and contact resistance are responsible for current variations. Thanks to the flexibility of the substrate and the low cost of the technology, this device opens the way for flexible mechanical sensors that can be used in a variety of innovative applications such as e-textiles and robotic interfaces.

  3. Analysis of Membrane Lipids of Airborne Micro-Organisms

    Science.gov (United States)

    MacNaughton, Sarah

    2006-01-01

    A method of characterization of airborne micro-organisms in a given location involves (1) large-volume filtration of air onto glass-fiber filters; (2) accelerated extraction of membrane lipids of the collected micro-organisms by use of pressurized hot liquid; and (3) identification and quantitation of the lipids by use of gas chromatography and mass spectrometry. This method is suitable for use in both outdoor and indoor environments; for example, it can be used to measure airborne microbial contamination in buildings ("sick-building syndrome"). The classical approach to analysis of airborne micro-organisms is based on the growth of cultureable micro-organisms and does not provide an account of viable but noncultureable micro-organisms, which typically amount to more than 90 percent of the micro-organisms present. In contrast, the present method provides an account of all micro-organisms, including cultureable, noncultureable, aerobic, and anaerobic ones. The analysis of lipids according to this method makes it possible to estimate the number of viable airborne micro-organisms present in the sampled air and to obtain a quantitative profile of the general types of micro-organisms present along with some information about their physiological statuses.

  4. Building Highly Flexible Polyelectrolyte Nanotubes

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Flexibility of polyelectrolyte nanotubes is necessary if they are to be exploited in applications such as developing photoelectric devices with strong mechanical properties. In a recent attempt, high flexibility has been observed from such nanotubes prepared by a research team headed by Prof. Li Junbai of the CAS Institute of Chemistry (ICCAS).

  5. On flexible and rigid nouns

    DEFF Research Database (Denmark)

    Rijkhoff, Jan

    2008-01-01

    , Non-Verb, Modifier), there are also flexible word classes within the rigid lexical category Noun (Set Noun, Sort Noun, General Noun). Members of flexible word classes are characterized by their vague semantics, which in the case of nouns means that values for the semantic features Shape...

  6. On flexible and rigid nouns

    DEFF Research Database (Denmark)

    Rijkhoff, Jan

    2010-01-01

    This article argues that in addition to the major flexible lexical categories in Hengeveld’s classification of parts of speech systems (Contentive, Non-Verb, Modifier), there are also flexible word classes within the rigid lexical category Noun (Set Noun, Sort Noun, General Noun). Members...

  7. Function Machines & Flexible Algebraic Thought.

    Science.gov (United States)

    Davis, Gary E.; McGowen, Mercedes A.

    This paper explores how college students understand ideas of functions, and which representations are productive for them in promoting their ability to work flexibly across representations. The study used pre- and post-test scores, and triangulations via student self evaluations, to generate a hypothesis related to flexible thinking and success in…

  8. Sensor Technologies on Flexible Substrates

    Science.gov (United States)

    Koehne, Jessica

    2016-01-01

    NASA Ames has developed sensor technologies on flexible substrates integrated into textiles for personalized environment monitoring and human performance evaluation. Current technologies include chemical sensing for gas leak and event monitoring and biological sensors for human health and performance monitoring. Targeted integration include next generation EVA suits and flexible habitats.

  9. Retirement Flexibility and Portfolio Choice

    NARCIS (Netherlands)

    Adema, Y.; Bonenkamp, J.; Meijdam, A.C.

    2011-01-01

    This paper explores the interaction between retirement flexibility and portfolio choice in an overlapping-generations model. We analyse this interaction both in a partial-equilibrium and general-equilibrium setting. Retirement flexibility is often seen as a hedge against capital-market risks which

  10. Flexible Coupling Corrects Shaft Misalinements

    Science.gov (United States)

    Mayo, R. A.

    1983-01-01

    Proposed flexible coupling provides nearly error free measurements of shaft rotation in presence of misalinements between shaft and position sensing transducer. Intended to be used in situations in which input or output shaft is mounted on flexible joint. Its function is to insure equal input and output angular velocities by forcing input and output shafts to remain parallel.

  11. DRAG REDUCTION EFFECT OF COUPLING FLEXIBLE TUBES WITH TURBULENT FLOW

    Institute of Scientific and Technical Information of China (English)

    CAI Shu-peng; JIN Guo-yu; LI Da-mei; Yang Lin

    2008-01-01

    To analyze the mechanism of drag reducing effect by coupling flexible tubes with turbulent flow, based on experimental examination of more obvious turbulent drag reduction effect in flexible tubes than in rigid tubes, experimental investigation was performed on the effect of turbulent drag reduction, fluctuating vibration characteristics of flexible tube and the correlations by using a double-tube system and laser displacement sensor. The results are as follows: with the decrease of the thickness of the flexible tubes, the root mean square of fluctuating amplitude of the outer wall of the tubes increases, and the non-dimensional burst period increases, resulting in the increase of the reduction rate of drag coefficient by coupling flexible tubes with turbulent flow. At applied pressure-balanced air on the outer wall and the Reynolds number of about 1.75 104, the non-dimensional burst periods of the flexible tubes with the thickness of 2 mm, 3 mm, 4 mm are 141, 126, 105, respectively.

  12. Functional aspects of protein flexibility

    DEFF Research Database (Denmark)

    Teilum, Kaare; Olsen, Johan G; Kragelund, Birthe B

    2009-01-01

    Proteins are dynamic entities, and they possess an inherent flexibility that allows them to function through molecular interactions within the cell, among cells and even between organisms. Appreciation of the non-static nature of proteins is emerging, but to describe and incorporate...... this into an intuitive perception of protein function is challenging. Flexibility is of overwhelming importance for protein function, and the changes in protein structure during interactions with binding partners can be dramatic. The present review addresses protein flexibility, focusing on protein-ligand interactions....... The thermodynamics involved are reviewed, and examples of structure-function studies involving experimentally determined flexibility descriptions are presented. While much remains to be understood about protein flexibility, it is clear that it is encoded within their amino acid sequence and should be viewed...

  13. Split-disk micro-lasers: Tunable whispering gallery mode cavities

    Directory of Open Access Journals (Sweden)

    T. Siegle

    2017-09-01

    Full Text Available Optical micro-cavities of various types have emerged as promising photonic structures, for both the investigation of fundamental science in cavity quantum electrodynamics and simultaneously for various applications, e.g., lasers, filters, or modulators. In either branch a demand for adjustable and tunable photonic devices becomes apparent, which has been mainly based on the modification of the refractive index of the micro-resonators so far. In this paper, we report on a novel type of whispering gallery mode resonator where resonance tuning is achieved by modification of the configuration. This is realized by polymeric split-disks consisting of opposing half-disks with an intermediate air gap. Functionality of the split-disk concept and its figures of merit like low-threshold lasing are demonstrated for laser dye-doped split-disks fabricated by electron beam lithography on Si substrates. Reversible resonance tuning is achieved for split-disks structured onto elastomeric substrates by direct laser writing. The gap width and hence the resonance wavelength can be well-controlled by mechanically stretching the elastomer and exploiting the lateral shrinkage of the substrate. We demonstrate a broad spectral tunability of laser modes by more than three times the free spectral range. These cavities have the potential to form a key element of flexible and tunable photonic circuits based on polymers.

  14. Split-disk micro-lasers: Tunable whispering gallery mode cavities

    Science.gov (United States)

    Siegle, T.; Remmel, M.; Krämmer, S.; Kalt, H.

    2017-09-01

    Optical micro-cavities of various types have emerged as promising photonic structures, for both the investigation of fundamental science in cavity quantum electrodynamics and simultaneously for various applications, e.g., lasers, filters, or modulators. In either branch a demand for adjustable and tunable photonic devices becomes apparent, which has been mainly based on the modification of the refractive index of the micro-resonators so far. In this paper, we report on a novel type of whispering gallery mode resonator where resonance tuning is achieved by modification of the configuration. This is realized by polymeric split-disks consisting of opposing half-disks with an intermediate air gap. Functionality of the split-disk concept and its figures of merit like low-threshold lasing are demonstrated for laser dye-doped split-disks fabricated by electron beam lithography on Si substrates. Reversible resonance tuning is achieved for split-disks structured onto elastomeric substrates by direct laser writing. The gap width and hence the resonance wavelength can be well-controlled by mechanically stretching the elastomer and exploiting the lateral shrinkage of the substrate. We demonstrate a broad spectral tunability of laser modes by more than three times the free spectral range. These cavities have the potential to form a key element of flexible and tunable photonic circuits based on polymers.

  15. [Flexible root posts].

    Science.gov (United States)

    Vadachkoriia, N R; Mandzhavidze, N A; Gumberidze, N Sh

    2009-02-01

    The article discusses the current state of restoration techniques of root canal treatment. Nowadays, technical progress allows manufacturers to develop flexible fiberglass posts, aspiring not only to an excellent aesthetics and mechanical properties (first of all, in comparison with metal and cast posts), but also to maintenance of their radio density and a wide range of forms. Growth of fiberglass posts popularity testifies to their clinical efficiency that also is confirmed by results of long-term researches. Introduction of fiberglass posts in a dental practice has rendered huge influence on restoration techniques of root canal treatment. Convincing factors of fiberglass posts superiority provide restoration the appearance similar with the natural dentition; possess close to dentine elasticity; creation of monolithic structure with hard tooth tissues and composite cement, posts, in case of need, can be easily adjusted on length, adhesive linkage of posts gives them additional stability. Modern researches have confirmed that only elastic, namely carbon fiber and the fiberglass posts made of modern technologies possess similar physical properties, as tooth structure. They can create reliable biomimetic design; solve a complex of aesthetic and functional restoration problems.

  16. Orthogonal flexible Rydberg aggregates

    Science.gov (United States)

    Leonhardt, K.; Wüster, S.; Rost, J. M.

    2016-02-01

    We study the link between atomic motion and exciton transport in flexible Rydberg aggregates, assemblies of highly excited light alkali-metal atoms, for which motion due to dipole-dipole interaction becomes relevant. In two one-dimensional atom chains crossing at a right angle adiabatic exciton transport is affected by a conical intersection of excitonic energy surfaces, which induces controllable nonadiabatic effects. A joint exciton-motion pulse that is initially governed by a single energy surface is coherently split into two modes after crossing the intersection. The modes induce strongly different atomic motion, leading to clear signatures of nonadiabatic effects in atomic density profiles. We have shown how this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains [K. Leonhardt et al., Phys. Rev. Lett. 113, 223001 (2014), 10.1103/PhysRevLett.113.223001]. In this article we discuss the underlying complex dynamics in detail, characterize the switch, and derive our isotropic interaction model from a realistic anisotropic one with the addition of a magnetic bias field.

  17. Orthogonal flexible Rydberg aggregates

    CERN Document Server

    Leonhardt, K; Rost, J M

    2015-01-01

    We study the link between atomic motion and exciton transport in flexible Rydberg aggregates, assemblies of highly excited light alkali atoms, for which motion due to dipole-dipole interaction becomes relevant. In two one-dimensional atom chains crossing at a right angle adiabatic exciton transport is affected by a conical intersection of excitonic energy surfaces, which induces controllable non-adiabatic effects. A joint exciton/motion pulse that is initially governed by a single energy surface is coherently split into two modes after crossing the intersection. The modes induce strongly different atomic motion, leading to clear signatures of non-adiabatic effects in atomic density profiles. We have shown how this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains [K.~Leonhardt {\\it et al.}, Phys.~Rev.~Lett. {\\bf 113} 223001 (2014)]. In this article we discuss the underlying complex dynamics in detail, characterise the ...

  18. A Set of Free Cross-Platform Authoring Programs for Flexible Web-Based CALL Exercises

    Science.gov (United States)

    O'Brien, Myles

    2012-01-01

    The Mango Suite is a set of three freely downloadable cross-platform authoring programs for flexible network-based CALL exercises. They are Adobe Air applications, so they can be used on Windows, Macintosh, or Linux computers, provided the freely-available Adobe Air has been installed on the computer. The exercises which the programs generate are…

  19. MANUAL: BEST MANAGEMENT PRACTICES FOR POLLUTION PREVENTION IN THE SLABSTOCK AND MOLDED FLEXIBLE POLYURETHANE FOAM INDUSTRY

    Science.gov (United States)

    The 1990 Clean Air Act Amendments require EPA to develop standards for major emission sources of 189 hazardous air pollutants (HAPs). EPA has identified the flexible polyurethane foam industry as a large emitter of HAPs and has slated the industry for regulation under Title III, ...

  20. MANUAL: BEST MANAGEMENT PRACTICES FOR POLLUTION PREVENTION IN THE SLABSTOCK AND MOLDED FLEXIBLE POLYURETHANE FOAM INDUSTRY

    Science.gov (United States)

    The 1990 Clean Air Act Amendments require EPA to develop standards for major emission sources of 189 hazardous air pollutants (HAPs). EPA has identified the flexible polyurethane foam industry as a large emitter of HAPs and has slated the industry for regulation under Title III, ...

  1. Flexible Blades for Wind Turbines

    Science.gov (United States)

    Collins, Madeline Carlisle; Macphee, David; Harris, Caleb

    2016-11-01

    Previous research has shown that windmills with flexible blades are more efficient than those with rigid blades. Flexibility offers passive pitch control, preferable to active pitch control which is costly and requires maintenance. Flexible blades morph such that the blade more closely resembles its design point at part load and over load. The lift-to-drag ratios on individual blades was investigated. A mold was designed and machined from an acrylic slab for the casting of blades with a NACA 0012 cross section. A flexible blade was cast from silicone and a rigid blade was cast from polyurethane. Each of these blades was tested in a wind tunnel, cantilever mounted, spanning the whole test section. The angle of attack was varied by rotating the mount. All tests were performed at the same wind speed. A load cell within the mount measured forces on the blade, from which the lift and drag forces were calculated. The stall point for the flexible blade occurred later than for the rigid blade, which agrees with previous research. Lift-to-drag ratios were larger for the flexible blade at all angles of attack tested. Flexible blades seem to be a viable option for passive pitch control. Future research will include different airfoil cross sections, wind speeds, and blade materials. Funding from NSF REU site Grant EEC 1358991 is greatly appreciated.

  2. Flexible Bond Wire Capacitive Strain Sensor for Vehicle Tyres

    Directory of Open Access Journals (Sweden)

    Siyang Cao

    2016-06-01

    Full Text Available The safety of the driving experience and manoeuvrability of a vehicle can be improved by detecting the strain in tyres. To measure strain accurately in rubber, the strain sensor needs to be flexible so that it does not deform the medium that it is measuring. In this work, a novel flexible bond wire capacitive strain sensor for measuring the strain in tyres is developed, fabricated and calibrated. An array of 25 micron diameter wire bonds in an approximately 8 mm × 8 mm area is built to create an interdigitated structure, which consists of 50 wire loops resulting in 49 capacitor pairs in parallel. Laser machining was used to pattern copper on a flexible printed circuit board PCB to make the bond pads for the wire attachment. The wire array was finally packaged and embedded in polydimethylsiloxane (PDMS, which acts as the structural material that is strained. The capacitance of the device is in a linear like relationship with respect to the strain, which can measure the strain up to at least ±60,000 micro-strain (±6% with a resolution of ~132 micro-strain (0.013%. In-tyre testing under static loading has shown the ability of the sensor to measure large tyre strains. The technology used for sensor fabrication lends itself to mass production and so the design is considered to be consistent with low cost commercialisable strain sensing technology.

  3. Scalable and Flexible heterogeneous multi-core system

    Directory of Open Access Journals (Sweden)

    Rashmi A Jain

    2013-01-01

    Full Text Available Multi-core system has wide utility in today’s applications due to less power consumption and high performance. Many researchers are aiming at improving the performance of these systems by providing flexible multi-core architecture. Flexibility in the multi-core processors system provides high throughput for uniform parallel applications as well as high performance for more general work. This flexibility in the architecture can be achieved by scalable and changeablesize window micro architecture. It uses the concept of execution locality to provide large-window capabilities. Use of high memory-level parallelism (MLP reduces the memory wall. Micro architecture contains a set of small and fast cache processors which execute high locality code. A network of small in-order memory engines use low locality code to improve performance by using instruction level parallelism (ILP. Dynamic heterogeneous multi-core architecture is capable of reconfiguring itself to fit application requirements. Study of different scalable and flexible architectures of heterogeneous multi-core system has been carried out and has been presented.

  4. Swarming: flexible roaming plans.

    Science.gov (United States)

    Partridge, Jonathan D; Harshey, Rasika M

    2013-03-01

    Movement over an agar surface via swarming motility is subject to formidable challenges not encountered during swimming. Bacteria display a great deal of flexibility in coping with these challenges, which include attracting water to the surface, overcoming frictional forces, and reducing surface tension. Bacteria that swarm on "hard" agar surfaces (robust swarmers) display a hyperflagellated and hyperelongated morphology. Bacteria requiring a "softer" agar surface (temperate swarmers) do not exhibit such a dramatic morphology. For polarly flagellated robust swarmers, there is good evidence that restriction of flagellar rotation somehow signals the induction of a large number of lateral flagella, but this scenario is apparently not relevant to temperate swarmers. Swarming bacteria can be further subdivided by their requirement for multiple stators (Mot proteins) or a stator-associated protein (FliL), secretion of essential polysaccharides, cell density-dependent gene regulation including surfactant synthesis, a functional chemotaxis signaling pathway, appropriate cyclic (c)-di-GMP levels, induction of virulence determinants, and various nutritional requirements such as iron limitation or nitrate availability. Swarming strategies are as diverse as the bacteria that utilize them. The strength of these numerous designs stems from the vantage point they offer for understanding mechanisms for effective colonization of surface niches, acquisition of pathogenic potential, and identification of environmental signals that regulate swarming. The signature swirling and streaming motion within a swarm is an interesting phenomenon in and of itself, an emergent behavior with properties similar to flocking behavior in diverse systems, including birds and fish, providing a convenient new avenue for modeling such behavior.

  5. Flexible armored blanket development

    Energy Technology Data Exchange (ETDEWEB)

    Roth, E.S.

    1978-05-01

    An exploratory development contract was undertaken on December 23, 1977 which had as its purpose the development and demonstration of a flexible armored blanket design suitable for providing ballistic protection to nuclear weapons during shipment. Objectives were to design and fabricate a prototype blanket which will conform to the weapon shape, is troop-handleable in the field, and which, singly or in multiple layers, can defeat a range of kinetic energy armor piercing (AP) ammunition potentially capable of damaging the critical portion of the nuclear weapon. Following empirical testing, including the firing of threat ammunition under controlled laboratory and field test conditions, materials were selected and assembled into two blanket designs, each weighing approximately 54 kg/m{sup 2} (11 lbs/ft{sup 2}) and estimated to cost from $111 to $180 per ft{sup 2} in production. A firing demonstration to evidence blanket performance against terrorist/light infantry weapons, heavy infantry weapons, and aircraft cannon was conducted for representatives of the DOD and interested Sandia employees on April 12, 1978. The blankets performed better than anticipated defeating bullets up to 7.62 mm x 51 mm AP with one layer and projectiles up to 23 mm HEI with two layers. Based on these preliminary tests it is recommended that development work be continued with the following objectives: (1) the selection by the DOD of priority applications, (2) the specific design and fabrication of sufficient quantities of armored blankets for field testing, (3) the evaluation of the blankets by DOD operational units, with reports to Sandia Laboratories to enable final design.

  6. Guideline Implementation: Processing Flexible Endoscopes.

    Science.gov (United States)

    Bashaw, Marie A

    2016-09-01

    The updated AORN "Guideline for processing flexible endoscopes" provides guidance to perioperative, endoscopy, and sterile processing personnel for processing all types of reusable flexible endoscopes and accessories in all procedural settings. This article focuses on key points of the guideline to help perioperative personnel safely and effectively process flexible endoscopes to prevent infection transmission. The key points address verification of manual cleaning, mechanical cleaning and processing, storage in a drying cabinet, determination of maximum storage time before reprocessing is needed, and considerations for implementing a microbiologic surveillance program. Perioperative RNs should review the complete guideline for additional information and for guidance when writing and updating policies and procedures.

  7. Pneumatic squirming robot based on flexible pneumatic actuator

    Science.gov (United States)

    Yang, Qinghua; Zhang, Libin; Bao, Guanjun; Ruan, Jian

    2005-12-01

    The design of a kind of pneumatic squirming robot is presented. It is based on the use of flexible pneumatic actuator. The flexible pneumatic actuator was made of caoutchouc. Its working principle is described. The structure, working principle, pneumatic and electrical control system of the pneumatic squirming robot are designed. All of the actuator's driving and squirming parts are composed of pneumatic elements. The vacuum osculums, which act as feet, are connected to the flexible pneumatic actuator. When the vacuum pumps operate, vacuum will be produced in the corresponding osculums, which can adsorb on the contacting surface and orient the robot. The actuator, operating under air pressure, drives the robot. By controlling the vacuum pumps and the actuator, straight and bending squirming of this robot can be obtained.

  8. Flexible Learning in a Digital World.

    Science.gov (United States)

    Collis, Betty; Moonen, Jef

    2002-01-01

    Defines flexible learning and describes components of flexible learning in higher education, including technology, pedagogy or instructional approach, implementation strategies, and institutional framework. Considers factors constraining learning flexibility; changing student characteristics; and the need for lifelong learning, particularly in the…

  9. Adaptation Through Flexibility: 656 Army Air Corps During Operation Corporate

    Science.gov (United States)

    2014-06-13

    Squadron RAF/AAC 1942-2012 (E. Yorkshire, England: Pen and Sword Aviation, 2013), 10. 3Ibid. 2 how little one could observe through dense forest ...NATO operations in the heavily forested Norway. Combined with the flatter nature of the Falklands’ ground, the ability for Scout and Gazelle aircraft...crews slept in two man tents until their relocation to Darwin and Goose Green where cow barns and pigsties became makeshift homes.201 They adapted to

  10. Exponential stabilization of a class of flexible microgrippers using dynamic boundary port Hamiltonian control.

    NARCIS (Netherlands)

    Ramirez, Hector; Le Gorrec, Yann; Zwart, Hans

    2013-01-01

    This paper deals with the control of a class of simplified models for flexible micro-grippers for DNA manipulation. The overall system is first modeled as a boundary controlled port-Hamiltonian system made up as the interconnection of an infinite-dimensional systems (modeled as an undamped Timoshenk

  11. A positive mood, a flexible brain

    OpenAIRE

    Betzel, Richard F.; Satterthwaite, Theodore D.; Gold, Joshua I.; Bassett, Danielle S.

    2016-01-01

    Flexible reconfiguration of human brain networks supports cognitive flexibility and learning. However, modulating flexibility to enhance learning requires an understanding of the relationship between flexibility and brain state. In an unprecedented longitudinal data set, we investigate the relationship between flexibility and mood, demonstrating that flexibility is positively correlated with emotional state. Our results inform the modulation of brain state to enhance response to training in h...

  12. Aggregating and Disaggregating Flexibility Objects

    DEFF Research Database (Denmark)

    Siksnys, Laurynas; Valsomatzis, Emmanouil; Hose, Katja

    2015-01-01

    In many scientific and commercial domains we encounter flexibility objects, i.e., objects with explicit flexibilities in a time and an amount dimension (e.g., energy or product amount). Applications of flexibility objects require novel and efficient techniques capable of handling large amounts...... energy data management and discuss strategies for aggregation and disaggregation of flex-objects while retaining flexibility. This paper further extends these approaches beyond flex-objects originating from energy consumption by additionally considering flex-objects originating from energy production...... and aiming at energy balancing during aggregation. In more detail, this paper considers the complete life cycle of flex-objects: aggregation, disaggregation, associated requirements, efficient incremental computation, and balance aggregation techniques. Extensive experiments based on real-world data from...

  13. Two-dimensional flexible nanoelectronics

    National Research Council Canada - National Science Library

    Akinwande, Deji; Petrone, Nicholas; Hone, James

    2014-01-01

    .... With the discovery of hexagonal boron nitride as an ideal dielectric, the materials are now in place to advance integrated flexible nanoelectronics, which uniquely take advantage of the unmatched...

  14. Flexible Transparent Electronic Gas Sensors.

    Science.gov (United States)

    Wang, Ting; Guo, Yunlong; Wan, Pengbo; Zhang, Han; Chen, Xiaodong; Sun, Xiaoming

    2016-07-01

    Flexible and transparent electronic gas sensors capable of real-time, sensitive, and selective analysis at room-temperature, have gained immense popularity in recent years for their potential to be integrated into various smart wearable electronics and display devices. Here, recent advances in flexible transparent sensors constructed from semiconducting oxides, carbon materials, conducting polymers, and their nanocomposites are presented. The sensing material selection, sensor device construction, and sensing mechanism of flexible transparent sensors are discussed in detail. The critical challenges and future development associated with flexible and transparent electronic gas sensors are presented. Smart wearable gas sensors are believed to have great potential in environmental monitoring and noninvasive health monitoring based on disease biomarkers in exhaled gas.

  15. Flexible sensors based on nanoparticles.

    Science.gov (United States)

    Segev-Bar, Meital; Haick, Hossam

    2013-10-22

    Flexible sensors can be envisioned as promising components for smart sensing applications, including consumer electronics, robotics, prosthetics, health care, safety equipment, environmental monitoring, homeland security and space flight. The current review presents a concise, although admittedly nonexhaustive, didactic review of some of the main concepts and approaches related to the use of nanoparticles (NPs) in flexible sensors. The review attempts to pull together different views and terminologies used in the NP-based sensors, mainly those established via electrical transduction approaches, including, but, not confined to: (i) strain-gauges, (ii) flexible multiparametric sensors, and (iii) sensors that are unaffected by mechanical deformation. For each category, the review presents and discusses the common fabrication approaches and state-of-the-art results. The advantages, weak points, and possible routes for future research, highlighting the challenges for NP-based flexible sensors, are presented and discussed as well.

  16. Flexible protection for metal bellows

    Science.gov (United States)

    Kimble, K. G.

    1970-01-01

    RTV silicone is used with a braided wire sheath surrounding the metal bellows in fluid transfer systems. It demonstrated best overall performance in flexibility and shock absorbing tests, high temperature, low temperature, and salt spray.

  17. High Performance Transfer Press for Precision Manufacturing of Micro Metal Parts

    DEFF Research Database (Denmark)

    Mahshid, Rasoul

    Micro forming technology has several notable benefits such as yielding remarkable accuracy, high production speed, material saving and good mechanical properties of formed parts which allows complex micro parts to be manufactured by this technology. There are also presses fabricated appropriately...... and handling concepts. The aim of this research primarily is to develop an integrated solution for micro metal forming based on a flexible tool with integrated handling operations. The study herein extends these finding by designing and implementation of a multi-step micro metal forming process based...... on the above developed handling solution including a fully instrumented flexible tool for micro metal forming with the above mentioned characteristics. For this research, the 1050 Aluminum Alloy was used for forming material while it is originally in the form of coil. This original stock was sectioned...

  18. FLEXIBLE FLATFOOT IN CHILDREN (REVIEW)

    OpenAIRE

    Владимир Маркович Кенис; Юрий Алексеевич Лапкин; Руслан Халилович Хусаинов; Андрей Викторович Сапоговский

    2014-01-01

    Flatfoot is one of the most common musculoskeletal conditions in the daily practice of pediatric orthopedists. Despite of numerous studies, diagnostic criteria and principles of management remain controversial. Flexible flatfoot - is visually detectable decrease in the height of the longitudinal arch of the foot, which can be spontaneously corrected by active or passive motion and not accompanied by any contracture of foot and ankle. Flexible flatfoot is a benign condition which is normal for...

  19. Value of Flexibility - Phase 1

    Science.gov (United States)

    2010-09-25

    flexibility could also change the calculus of how we determine when to start a new program vice modifying an existing one. Flexibility could even help...decades ago by Steward as a ‖framework for formally identifying and tracking relationships between design variables‖ [ Steward , 1981]. Keese [2007...Paper presented at the 6th Conference on Systems Engineering Research, Los Angeles, CA. Shreve, S. E. (2004). Stochastic calculus for finance. New

  20. Flexible packaging for PV modules

    Science.gov (United States)

    Dhere, Neelkanth G.

    2008-08-01

    Economic, flexible packages that provide needed level of protection to organic and some other PV cells over >25-years have not yet been developed. However, flexible packaging is essential in niche large-scale applications. Typical configuration used in flexible photovoltaic (PV) module packaging is transparent frontsheet/encapsulant/PV cells/flexible substrate. Besides flexibility of various components, the solder bonds should also be flexible and resistant to fatigue due to cyclic loading. Flexible front sheets should provide optical transparency, mechanical protection, scratch resistance, dielectric isolation, water resistance, UV stability and adhesion to encapsulant. Examples are Tefzel, Tedlar and Silicone. Dirt can get embedded in soft layers such as silicone and obscure light. Water vapor transmittance rate (WVTR) of polymer films used in the food packaging industry as moisture barriers are ~0.05 g/(m2.day) under ambient conditions. In comparison, light emitting diodes employ packaging components that have WVTR of ~10-6 g/(m2.day). WVTR of polymer sheets can be improved by coating them with dense inorganic/organic multilayers. Ethylene vinyl acetate, an amorphous copolymer used predominantly by the PV industry has very high O2 and H2O diffusivity. Quaternary carbon chains (such as acetate) in a polymer lead to cleavage and loss of adhesional strength at relatively low exposures. Reactivity of PV module components increases in presence of O2 and H2O. Adhesional strength degrades due to the breakdown of structure of polymer by reactive, free radicals formed by high-energy radiation. Free radical formation in polymers is reduced when the aromatic rings are attached at regular intervals. This paper will review flexible packaging for PV modules.

  1. Flexible solar-array mechanism

    Science.gov (United States)

    Olson, M. C.

    1972-01-01

    One of the key elements of the flexible rolled-up solar array system is a mechanism to deploy, retract, and store the flexible solar-cell arrays. The selection of components, the design of the mechanism assembly, and the tests that were performed are discussed. During 6 months in orbit, all mission objectives were satisfied, and inflight performance has shown good correlation with preflight analyses and tests.

  2. Flexible Learning Spaces Evaluation Report

    OpenAIRE

    Bullimore, A.; Reader, K.; Sultany, A

    2013-01-01

    City University, London is tackling the challenge of ensuring the learning spaces provided are able to meet the anticipated increase in technology usage and prevalent pedagogies. There is no longer a standard classroom design that will achieve this goal and therefore it is imperative to pilot and explore a variety of flexible learning spaces. This report feeds back on an\\ud evaluation of two flexible learning space approaches piloted in the autumn term of 2012 as alternatives to traditional c...

  3. EDITORIAL: Nanotechnology-based flexible electronics Nanotechnology-based flexible electronics

    Science.gov (United States)

    Subramanian, Vivek; Lee, Takhee

    2012-08-01

    nanomaterials as building blocks. Developments in the field will help to leverage the power of these materials to realize novel functionalities in flexible form factors. This special issue provides a view of the state of the art in these technologies, and gives a vision of the coming innovations that will make flexible electronics a reality. References [1] Gelinck G H et al 2004 Flexible active-matrix displays and shift registers based on solution-processed organic transistors Nature Mater. 3 106-10 [2] Zhou L, Wanga A, Wu S C, Sun J, Park S and Jackson T N 2006 All-organic active matrix flexible display Appl. Phys. Lett. 88 083502 [3] Fan Z, Ho J C, Jacobson Z A, Razavi H and Javey A 2008 Large-scale, heterogeneous integration of nanowire arrays for image sensor circuitry Proc. Natl Acad. Sci. 105 11066 [4] Sekitani T et al 2009 Organic nonvolatile memory transistors for flexible sensor arrays Science 326 1516-9 [5] Mannsfeld S C B et al 2010 Highly sensitive flexible pressure sensors with microstructured rubber dielectric layers Nature Mater. 9 859-64 [6]Subramanian V, Frechet J M J, Chang P C, Huang D C, Lee J B, Molesa S E, Murphy A R, Redinger D R and Volkman S K 2005 Progress toward development of all-printed RFID tags: materials, processes, and devices Proc. IEEE 93 1330-8 [7] Jung M et al 2010 All-printed and roll-to-roll-printable 13.56 MHz-operated 1 bit RF tag on plastic foils IEEE Trans. Electron. Devices 57 571-80 [8] Kim D-H et al 2011 Epidermal electronics Science 333 838-43 [9] Wagner S and Bauer S 2012 Materials for stretchable electronics MRS Bull. 37 207 [10] Grouchko M, Kamyshny A and Magdassi S 2009 Formation of air-stable copper-silver core-shell nanoparticles for inkjet printing J. Mater. Chem. 19 3057-62 [11] Takei K et al 2010 Nanowire active-matrix circuitry for low-voltage macroscale artificial skin Nature Mater. 9 821-6 [12] Sekitani T, Zschieschang U, Klauk H and Someya T 2010 Flexible organic transistors and circuits with extreme bending stability

  4. Stiffness requirement of flexible skin for variable trailing-edge camber wing

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The method for analyzing the deformation of flexible skin under the air loads was developed based on the panel method and finite element method.The deformation of flexible skin under air pressures and effects of the local deformation on the aerodynamic characteristics were discussed.Numerical results show that the flexible skin on the upper surface of trailing-edge will bubble under the air loads and the bubble has a powerful effect on the aerodynamic pressure near the surface of local deforma-tion.Then the stiffness requirements for flexible skin of variable trailing-edge were given by using the Jacobs rule,i.e.,the maximum displacement of skin is not greater than 0.1% of wing chord.Results show that the in-plane stiffness can be reduced by increasing the ratio of bending stiffness to in-plane stiffness.Although the deformation of flexible skin increases with the in-plane stiffness decreasing,it depends on the bending stiffness.When the bending stiffness exceeds critical value,the deformation of flexible skin only depends on the bending stiffness and has nothing to do with the in-plane stiffness.The conclusions can be used for the structural design of flexible skin.

  5. Developmental constraints on behavioural flexibility.

    Science.gov (United States)

    Holekamp, Kay E; Swanson, Eli M; Van Meter, Page E

    2013-05-19

    We suggest that variation in mammalian behavioural flexibility not accounted for by current socioecological models may be explained in part by developmental constraints. From our own work, we provide examples of constraints affecting variation in behavioural flexibility, not only among individuals, but also among species and higher taxonomic units. We first implicate organizational maternal effects of androgens in shaping individual differences in aggressive behaviour emitted by female spotted hyaenas throughout the lifespan. We then compare carnivores and primates with respect to their locomotor and craniofacial adaptations. We inquire whether antagonistic selection pressures on the skull might impose differential functional constraints on evolvability of skulls and brains in these two orders, thus ultimately affecting behavioural flexibility in each group. We suggest that, even when carnivores and primates would theoretically benefit from the same adaptations with respect to behavioural flexibility, carnivores may nevertheless exhibit less behavioural flexibility than primates because of constraints imposed by past adaptations in the morphology of the limbs and skull. Phylogenetic analysis consistent with this idea suggests greater evolutionary lability in relative brain size within families of primates than carnivores. Thus, consideration of developmental constraints may help elucidate variation in mammalian behavioural flexibility.

  6. Oxide Heteroepitaxy for Flexible Optoelectronics.

    Science.gov (United States)

    Bitla, Yugandhar; Chen, Ching; Lee, Hsien-Chang; Do, Thi Hien; Ma, Chun-Hao; Qui, Le Van; Huang, Chun-Wei; Wu, Wen-Wei; Chang, Li; Chiu, Po-Wen; Chu, Ying-Hao

    2016-11-30

    The emerging technological demands for flexible and transparent electronic devices have compelled researchers to look beyond the current silicon-based electronics. However, fabrication of devices on conventional flexible substrates with superior performance are constrained by the trade-off between processing temperature and device performance. Here, we propose an alternative strategy to circumvent this issue via the heteroepitaxial growth of transparent conducting oxides (TCO) on the flexible mica substrate with performance comparable to that of their rigid counterparts. With the examples of ITO and AZO as a case study, a strong emphasis is laid upon the growth of flexible yet epitaxial TCO relying muscovite's superior properties compared to those of conventional flexible substrates and its compatibility with the present fabrication methods. Besides excellent optoelectro-mechanical properties, an additional functionality of high-temperature stability, normally lacking in the current state-of-the-art transparent flexitronics, is provided by these heterostructures. These epitaxial TCO electrodes with good chemical and thermal stabilities as well as mechanical durability can significantly contribute to the field of flexible, light-weight, and portable smart electronics.

  7. Micro-propulsion and micro-combustion; Micropropulsion microcombustion

    Energy Technology Data Exchange (ETDEWEB)

    Ribaud, Y.; Dessornes, O.

    2002-10-01

    The AAAF (french space and aeronautic association) organized at Paris a presentation on the micro-propulsion. The first part was devoted to the thermal micro-machines for micro drones, the second part to the micro-combustion applied to micro-turbines. (A.L.B.)

  8. GLOBAL INTEGRATED ISR: A BETTER ORGANIZATIONAL CONSTRUCT FOR AIR FORCE LD/HD ISR

    Science.gov (United States)

    2017-04-06

    AIR WAR COLLEGE AIR UNIVERSITY GLOBAL INTEGRATED ISR: A BETTER ORGANIZATIONAL CONSTRUCT FOR AIR FORCE LD/HD ISR by Nicholas A. Nobriga...agility and flexibility in order to counter trans-regional threats seamlessly. This is especially true for the Air Force’s fleet of U-2, RQ-4, RC-135, and...Concept for Joint Operations: Joint Force 2020—providing maximum global agility and flexibility .3 Current trends around the globe point toward a future

  9. Preliminary Investigation on Generation of Electricity Using Micro Wind Turbines Placed on A Car

    Directory of Open Access Journals (Sweden)

    Yogendra Chaudhary

    2017-03-01

    Full Text Available Wind energy is one of the prominent resources for renewable energy and it is traditionally extracted using stationary wind turbines. However, it can also be extracted using mini or micro wind turbines on a moving body, such as an automobile, while cruising at high speeds on freeways. If the electricity is produced using air flowing around the vehicle without affecting aerodynamic performance of the vehicle, it can be used to charge up the battery or power up additional accessories of the vehicle. For the first time, in the present work, a preliminary investigation was carried out to generate electricity by utilizing air flow on a moving car. Initially, a correlation between the car speed and wind velocity was established using an anemometer. Placing a set of two micro wind turbines along with two micro generators on the rear end of the car trunk, the present study investigated the feasibility of generating electricity from these micro wind turbines while evaluating the effect of drag force on the performance of the car through the experimental approach and computational fluid dynamics (CFD simulations. Both approaches confirmed negligible effect of drag force on the vehicle performance in terms of gas mileage and changes in drag coefficient values. Following these studies, the micro wind turbines were also tested for electricity generation at various cruising speeds of the car ranging from 50 to 80 mph on the freeways. The voltage and power generated always showed an increasing trend with increasing the car speed, however they saturated when a cut off limit was setup with the voltage controllers. A maximum voltage of 3.5 V and a maximum current of 0.8 A were generated by each micro wind turbine when a cut off limit was used along with a load consisting of four LED bulbs in parallel with 3.5 V and 0.2 A rating each. On the other hand, when the tests were repeated without using the cut-off limit, a maximum voltage of 18.91 V and a maximum current

  10. Micro-Organ Device

    Science.gov (United States)

    Gonda, Steve R. (Inventor); Chang, Robert C. (Inventor); Starly, Binil (Inventor); Culbertson, Christopher (Inventor); Holtorf, Heidi L. (Inventor); Sun, Wei (Inventor); Leslie, Julia (Inventor)

    2013-01-01

    A method for fabricating a micro-organ device comprises providing a microscale support having one or more microfluidic channels and one or more micro-chambers for housing a micro-organ and printing a micro-organ on the microscale support using a cell suspension in a syringe controlled by a computer-aided tissue engineering system, wherein the cell suspension comprises cells suspended in a solution containing a material that functions as a three-dimensional scaffold. The printing is performed with the computer-aided tissue engineering system according to a particular pattern. The micro-organ device comprises at least one micro-chamber each housing a micro-organ; and at least one microfluidic channel connected to the micro-chamber, wherein the micro-organ comprises cells arranged in a configuration that includes microscale spacing between portions of the cells to facilitate diffusion exchange between the cells and a medium supplied from the at least one microfluidic channel.

  11. Flexible multi-electrode array with integrated bendable CMOS-chip for implantable systems.

    Science.gov (United States)

    Winkin, N; Mokwa, W

    2012-01-01

    Micro-electrodes and micro-electrode arrays (MEAs) for stimulating neurons or recording action potentials are widely used in medical applications or biological research. For medical implants in many applications like brain implants or retinal implants there is a need for flexible MEAs with a large area and a large number of stimulation electrodes. In this work a flexible MEA with an embedded flexible silicon dummy CMOS-chip facing these challenges has been designed, manufactured and characterized. This approach offers the possibility by connecting and addressing several of these MEAs via a bus system, to increase the number and the density of electrodes significantly. This paper describes the design and fabrication process. Results on the mechanical and electrical behavior will be given and possible improvements for medical applications by this novel approach will be discussed.

  12. Measure Guideline: Optimizing the Configuration of Flexible Duct Junction Boxes

    Energy Technology Data Exchange (ETDEWEB)

    Beach, R.; Burdick, A.

    2014-03-01

    This measure guideline offers additional recommendations to heating, ventilation, and air conditioning (HVAC) system designers for optimizing flexible duct, constant-volume HVAC systems using junction boxes within Air Conditioning Contractors of America (ACCA) Manual D guidance (Rutkowski, H. Manual D -- Residential Duct Systems, 3rd edition, Version 1.00. Arlington, VA: Air Conditioning Contractors of America, 2009.). IBACOS used computational fluid dynamics software to explore and develop guidance to better control the airflow effects of factors that may impact pressure losses within junction boxes among various design configurations (Beach, R., Prahl, D., and Lange, R. CFD Analysis of Flexible Duct Junction Box Design. Golden, CO: National Renewable Energy Laboratory, submitted for publication 2013). These recommendations can help to ensure that a system aligns more closely with the design and the occupants' comfort expectations. Specifically, the recommendations described herein show how to configure a rectangular box with four outlets, a triangular box with three outlets, metal wyes with two outlets, and multiple configurations for more than four outlets. Designers of HVAC systems, contractors who are fabricating junction boxes on site, and anyone using the ACCA Manual D process for sizing duct runs will find this measure guideline invaluable for more accurately minimizing pressure losses when using junction boxes with flexible ducts.

  13. Nonlinear vibration with control for flexible and adaptive structures

    CERN Document Server

    Wagg, David

    2015-01-01

    This book provides a comprehensive discussion of nonlinear multi-modal structural vibration problems, and shows how vibration suppression can be applied to such systems by considering a sample set of relevant control techniques. It covers the basic principles of nonlinear vibrations that occur in flexible and/or adaptive structures, with an emphasis on engineering analysis and relevant control techniques. Understanding nonlinear vibrations is becoming increasingly important in a range of engineering applications, particularly in the design of flexible structures such as aircraft, satellites, bridges, and sports stadia. There is an increasing trend towards lighter structures, with increased slenderness, often made of new composite materials and requiring some form of deployment and/or active vibration control. There are also applications in the areas of robotics, mechatronics, micro electrical mechanical systems, non-destructive testing and related disciplines such as structural health monitoring. Two broader ...

  14. Flexible organic solar cells including efficiency enhancing grating structures

    Science.gov (United States)

    Melina de Oliveira Hansen, Roana; Liu, Yinghui; Madsen, Morten; Rubahn, Horst-Günter

    2013-04-01

    In this work, a new method for the fabrication of organic solar cells containing functional light-trapping nanostructures on flexible substrates is presented. Polyimide is spin-coated on silicon support substrates, enabling standard micro- and nanotechnology fabrication techniques, such as photolithography and electron-beam lithography, besides the steps required for the bulk-heterojunction organic solar cell fabrication. After the production steps, the solar cells on polyimide are peeled off the silicon support substrates, resulting in flexible devices containing nanostructures for light absorption enhancement. Since the solar cells avoid using brittle electrodes, the performance of the flexible devices is not affected by the peeling process. We have investigated three different nanostructured grating designs and conclude that gratings with a 500 nm pitch distance have the highest light-trapping efficiency for the selected active layer material (P3HT:PCBM), resulting in an enhancement of about 34% on the solar cell efficiency. The presented method can be applied to a large variety of flexible nanostructured devices in future applications.

  15. Lightweight, Flexible Photovoltaic Module Project

    Data.gov (United States)

    National Aeronautics and Space Administration — With recent advances in MicroLink's inverted metamorphic (IMM) multijunction epitaxial lift off (ELO) solar cells, new opportunities for solar cell packaging are...

  16. Flexible printed circuit boards laser bonding using a laser beam homogenization process

    Science.gov (United States)

    Kim, Joohan; Choi, Haewoon

    2012-11-01

    A laser micro-bonding process using laser beam shaping is successfully demonstrated for flexible printed circuit boards. A CW Ytterbium fiber laser with a wavelength of 1070 nm and a laser power density of 1-7 W/mm2 is employed as a local heat source for bonding flexible printed circuit boards to rigid printed circuit boards. To improve the bonding quality, a micro-lens array is used to modify the Gaussian laser beam for the bonding process. An electromagnetic modeling and heat transfer simulation is conducted to verify the effect of the micro-lens array on the laser bonding process. The optimal bonding parameters are found experimentally. As the measured temperature ramp rate of the boards exceeds 1100 K/s, bonding occurs within 100-200 ms at a laser power density of 5 W/mm2. The bonding quality of the FPCB is verified with a shear strength test. Process characteristics are also discussed.

  17. Fuzzy Based Analysis of Inverter Fed Micro Grid in Islanding Operation

    Directory of Open Access Journals (Sweden)

    Yuvaraja Teekaraman

    2015-02-01

    Full Text Available In general islanding operation referred as isolation part of power system including distributed generation. This paper presents fuzzy logic controller for inverter fed micro-grid in islanding operation. Power electronics supports well by providing the control and flexibility required for the micro grid concept. Correctly designed controller insures that the micro grid can meet its utility’s needs. The efficiency and robust is counted in the design of fuzzy system. The simulation is done using MATLAB SIMULINK. The simulation results show very good consistency and show significance for the control of inverters in micro grid.

  18. Improved flexibility with grayscale fabrication of calcium fluoride homogenizers

    Science.gov (United States)

    Brown, Jeremiah; Brakhage, Peter; Simmons, Lamarr; Mueller, Ralf

    2012-03-01

    High quality and highly uniform illumination is a critical component for advanced lithography systems and wafer inspection tools. Homogenizer elements fabricated in calcium fluoride have demonstrated good performance for deep UV applications. Grayscale photolithography allows for the fabrication of single-sided micro lens array (MLA) elements with excellent optical performance. The MLA offers some significant advantages over crossed cylinders fabricated using grayscale photolithography processes, including the reduction in the number of fabrication steps and the added flexibility of manufacturing noncylindrical surface geometries. This research presentation reviews the fabrication process and compares grayscale crossed cylindrical arrays and MLAs in terms of their capabilities and performance.

  19. A simple implantation method for flexible, multisite microelectrodes into rat brains

    Directory of Open Access Journals (Sweden)

    Anja eRichter

    2013-07-01

    Full Text Available A long term functional and reliable coupling between neural tissue and implanted microelectrodes is the key issue in acquiring neural electrophysiological signals or therapeutically excite neural tissue. The currently often used rigid micro-electrodes are thought to cause a severe foreign body reaction resulting in a thick glial scar and consequently a poor tissue-electrode coupling in the chronic phase. We hypothesize, that this adverse effect might be remedied by probes compliant to the soft brain tissue, i.e. replacing rigid electrodes by flexible ones. Unfortunately, this flexibility comes at the price of a low stiffness, which makes targeted low trauma implantation very challenging. In this study, we demonstrate an adaptable and simple method to implant extremely flexible microprobes even to deep areas of rat’s brain. Implantation of flexible probes is achieved by rod supported stereotactic insertion fostered by a hydrogel (2% agarose in PBS cushion on the exposed skull. We were thus able to implant very flexible micro-probes in 70 rats as deep as the rodent's subthalamic nucleus. This work describes in detail the procedures and steps needed for minimal invasive, but reliable implantation of flexible probes.

  20. A simple implantation method for flexible, multisite microelectrodes into rat brains.

    Science.gov (United States)

    Richter, Anja; Xie, Yijing; Schumacher, Anett; Löffler, Susanne; Kirch, Robert D; Al-Hasani, Jaafar; Rapoport, Daniel H; Kruse, Charli; Moser, Andreas; Tronnier, Volker; Danner, Sandra; Hofmann, Ulrich G

    2013-01-01

    A long term functional and reliable coupling between neural tissue and implanted microelectrodes is the key issue in acquiring neural electrophysiological signals or therapeutically excite neural tissue. The currently often used rigid micro-electrodes are thought to cause a severe foreign body reaction resulting in a thick glial scar and consequently a poor tissue-electrode coupling in the chronic phase. We hypothesize, that this adverse effect might be remedied by probes compliant to the soft brain tissue, i.e., replacing rigid electrodes by flexible ones. Unfortunately, this flexibility comes at the price of a low stiffness, which makes targeted low trauma implantation very challenging. In this study, we demonstrate an adaptable and simple method to implant extremely flexible microprobes even to deep areas of rat's brain. Implantation of flexible probes is achieved by rod supported stereotactic insertion fostered by a hydrogel (2% agarose in PBS) cushion on the exposed skull. We were thus able to implant very flexible micro-probes in 70 rats as deep as the rodent's subthalamic nucleus. This work describes in detail the procedures and steps needed for minimal invasive, but reliable implantation of flexible probes.