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Sample records for cubic pin finned

  1. The Experimental Study of Atmospheric Stirling Engines Using Pin-Fin Arrays' Heat Exchangers

    Science.gov (United States)

    Isshiki, Seita; Sato, Hidekazu; Konno, Shoji; Shiraishi, Hiroaki; Isshiki, Naotsugu; Fujii, Iwane; Mizui, Hiroyuki

    This paper reports experimental results on two kinds of atmospheric Stirling engines that were designed and manufactured using a pin-fin array heat exchanger for the heater and cooler (abbreviated to “pin-fin Stirling engine” hereafter). The first one is a large β type pin-fin Stirling engine with a 1.7-liter displacement volume and power piston volume. The heater consists of an aluminum circular disk with a diameter of 270mm and with large-scale pin-fin arrays carved into the surface. The maximum output reached 91W at a temperature difference of 330K, which is 36% of the scheduled value and 68% of the Kolin's cubic power law. The maximum thermal efficiency was estimated 4.2%. The second engine is an α type pin-fin Stirling engine. Glass syringes were used for the piston-cylinder system and the Ross-yoke mechanism was used for the crank mechanism. By changing temperature difference, the characteristic of output torque in the large range was measured with a precision torque detector.

  2. Boiling of HFE-7100 on a Straight Pin Fin

    Institute of Scientific and Technical Information of China (English)

    Z. W. Liu; W.W. Lin; D.J. Lee; J.P. Hsu

    2001-01-01

    This paper deals with an experimental investigation of pin fin boiling of saturated and subcooled HFE-7100 under atmospheric pressure. Fin base temperature and heat flux data are measured along with the fin tip temperature. The basic features of boiling stability of HFE-7100 boiling on pin fin had been reported for the first time. For a given liquid/heating surface combination there exist upper steady-state (USS) branch and lower steady-state (LSS)branch, and a large, unstable regime located in between. Zones with different stability characteristics are mapped according to boiling on fins with different aspect ratios. Liquid subcooling can largely enhance heat transfer performance. A longer fin can provide a safer operation.

  3. Research on the Pin Fin Efficiency and Structure

    Directory of Open Access Journals (Sweden)

    Fan Bailin

    2013-06-01

    Full Text Available The performance of pin fin heat sink can be to measure through the temperature field. The temperature field and efficiency of the Pin Fin were analyzed, Pin fin efficiency curve was drowned also the distribution of the temperature field along the length of the pin fin curve was drawn. Thermal resistance was composed by thermal resistance of Aluminum substrate、 thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. The change rule was studied through the calculation on Aluminum plate thermal resistance、 thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. Its change regularity was simulated by toolbox In the MATLAB, and it was found that thermal resistance of convective heat transfer effect on the efficiency was most obvious in a certain amount of the heat and flow for thermal resistance of the Pin-fin radiator under the premise. The structural parameters of radiator were related to the size of thermal resistance.

  4. Performance comparison of pin fin in-duct flow arrays with various pin cross-sections

    Energy Technology Data Exchange (ETDEWEB)

    Sahiti, N. [LSTM-Erlangen, Institute of Fluid Mechanics, Friedrich-Alexander-University, Erlangen-Nuremberg, Cauerstr. 4, D-91058 Erlangen (Germany)]. E-mail: sahiti@lstm.uni-erlangen.de; Lemouedda, A. [Department of Process Engineering, Georg-Simon-Ohm University of Applied Sciences, Wassertorstr. 10, D-90489 Nuremberg (Germany); Stojkovic, D. [LSTM-Erlangen, Institute of Fluid Mechanics, Friedrich-Alexander-University, Erlangen-Nuremberg, Cauerstr. 4, D-91058 Erlangen (Germany); Durst, F. [LSTM-Erlangen, Institute of Fluid Mechanics, Friedrich-Alexander-University, Erlangen-Nuremberg, Cauerstr. 4, D-91058 Erlangen (Germany); Franz, E. [Department of Process Engineering, Georg-Simon-Ohm University of Applied Sciences, Wassertorstr. 10, D-90489 Nuremberg (Germany)

    2006-08-15

    Pin fin arrays are frequently used for cooling of high thermal loaded electronic components. Whereas the pin fin accomplishment regarding heat transfer is always higher than that of other fin configurations, the high pressure drop accompanying pins seriously reduces their overall performance. In order to check how the form of pin cross-section influences the pressure drop and heat transfer capabilities, six forms of pin cross-section were numerically investigated. By employing the conjugate heat transfer boundary conditions, numerical simulations close to realistic working conditions were performed. Two geometric comparison criteria were applied so that the conclusions derived from numerical computations were valid for various possible geometric parameters and working conditions. Both staggered and inline pin arrangements were investigated as these are common in practical applications. The heat transfer and pressure drop characteristics are presented in terms of appropriate dimensionless variables. The final judgment of the performance of the pin fin cross-section was performed based on the heat exchanger performance plot. Such a plot allows the assessment of the pin performance including their heat transfer and the pressure drop.

  5. An experimental study of a pin-fin heat exchanger

    OpenAIRE

    Ramthun, David L.

    2003-01-01

    Approved for public release; distribution is unlimited A detailed experimental study has been carried out on the heat transfer and pressure drop characteristics of a compact heat exchanger with pin fins. A modular wind-tunnel with a rectangular cross-section duct-flow area was constructed that would accommodate the heat exchanger test section with varying pin designs. The flow in the tunnel was achieved through a suction-type blower, and a leading entrance length section was added to achie...

  6. Experimental study on thermal performance of micro pin fin heat sinks with various shapes

    Science.gov (United States)

    Hua, Junye; Li, Gui; Zhao, Xiaobao; Li, Qihe

    2017-03-01

    This paper presents a visualization experimental study on the heat transfer characteristics of various shapes of micro pin fins, including the circular, ellipse, diamond, square and triangle shape micro pin fin arrays with various equivalent diameters and pin fin density. The influences study of different sizes and shapes of pin fin on Nusselt number and heat transfer coefficient have been conducted. The results show that with the increase of the flow rate, the temperature of the bottom of the experimental section decreases. And the Nusselt number of different shapes of micro pin fins increases with the increase of Re. In which, the heat transfer performance of the ellipse shape pin fin appears better among the other shapes of pin fins. However, the higher pin fin of the ellipse shape density leads to a weaker flow performance. Besides, the micro-scale heat transfer correlation between the Nusselt number and the Reynolds number is fitted based on the experimental data.

  7. Design optimization of pin fin geometry using particle swarm optimization algorithm.

    Directory of Open Access Journals (Sweden)

    Nawaf Hamadneh

    Full Text Available Particle swarm optimization (PSO is employed to investigate the overall performance of a pin fin.The following study will examine the effect of governing parameters on overall thermal/fluid performance associated with different fin geometries, including, rectangular plate fins as well as square, circular, and elliptical pin fins. The idea of entropy generation minimization, EGM is employed to combine the effects of thermal resistance and pressure drop within the heat sink. A general dimensionless expression for the entropy generation rate is obtained by considering a control volume around the pin fin including base plate and applying the conservations equations for mass and energy with the entropy balance. Selected fin geometries are examined for the heat transfer, fluid friction, and the minimum entropy generation rate corresponding to different parameters including axis ratio, aspect ratio, and Reynolds number. The results clearly indicate that the preferred fin profile is very dependent on these parameters.

  8. Numerical Evaluation of Flow and Heat Transfer in Plate-Pin Fin Heat Sinks with Various Pin Cross-Sections

    OpenAIRE

    Zhou, Feng; Catton, Ivan

    2011-01-01

    A numerical investigation of the thermal and hydraulic performance of twenty different plate-pin fin heat sinks with various shapes of pin cross-section (square, circular, elliptic, NACA profile and dropform) and different ratios of pin widths to plate fin spacing (0.3, 0.4, 0.5 and 0.6) was performed. Finite Volume Method based CFD software, Ansys CFX, was used as the 3-D Reynolds-averaged Navier-Stokes Solver. A k-ω based Shear-Stress-Transport model was used to predict the turbulent flow a...

  9. Cooling system having reduced mass pin fins for components in a gas turbine engine

    Science.gov (United States)

    Lee, Ching-Pang; Jiang, Nan; Marra, John J

    2014-03-11

    A cooling system having one or more pin fins with reduced mass for a gas turbine engine is disclosed. The cooling system may include one or more first surfaces defining at least a portion of the cooling system. The pin fin may extend from the surface defining the cooling system and may have a noncircular cross-section taken generally parallel to the surface and at least part of an outer surface of the cross-section forms at least a quartercircle. A downstream side of the pin fin may have a cavity to reduce mass, thereby creating a more efficient turbine airfoil.

  10. Shape optimization of rotating rectangular channels with pin-fins by kriging method

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Mi Ae; Husain, Afzal; Kim, Kwang Yong [Inha Univ., Incheon (Korea, Republic of)

    2009-07-01

    This paper presents numerical optimization of the design of a rotating rectangular channel with staggered arrays of pin-fins with Kriging metamodeling technique. Two non-dimensional variables, the ratio of the height to diameter of the pin-fin and the ratio of the spacing between the pin-fins to diameter of the pin-fins are chosen as design variables. The objective function as a linear combination of heat transfer and friction loss related terms with a weighting factor is selected for the optimization. Objective function values at twenty training points generated by Latin Hypercube Sampling (LHS) are evaluated by three-dimensional ReynoldsAveraged Navier-Stokes (RANS) method with the Shear Stress Transport (SST) turbulence model. The prediction of objective function by Kriging metamodeling at optimum point shows reasonable accuracy in comparison with the values calculated by RANS analysis. With increase in height of the pin-fin, heat transfer is decreased and at the same time pressure drop is also decreased, while opposite behavior is obtained for the pin-fin spacing.

  11. Flux pinning effect of cubic equiaxed morphology and its Ti stabilizing in Nb3Sn superconductors

    Institute of Scientific and Technical Information of China (English)

    ZHANG ChaoWu; ZHOU Lian; Andre SULPICE; Jean-Louis SOUBEYROUX; TANG XianDe; Christophe VERWAERDE; Gia Ky HOANG

    2009-01-01

    zes the cubic equiaxed phase at lower temperature so that heat reaction temperature is effectively reduced,the flux pinning performance is largely reinforced and the transport critical current density Jc is substantially promoted.

  12. Performance analysis of pin fins with temperature dependent thermal parameters using the variation of parameters method

    Directory of Open Access Journals (Sweden)

    Cihat Arslantürk

    2016-08-01

    Full Text Available The performance of pin fins transferring heat by convection and radiation and having variable thermal conductivity, variable emissivity and variable heat transfer coefficient was investigated in the present paper. Nondimensionalizing the fin equation, the problem parameters which affect the fin performance were obtained. Dimensionless nonlinear fin equation was solved with the variation of parameters method, which is quite new in the solution of nonlinear heat transfer problems. The solution of variation of parameters method was compared with known analytical solutions and some numerical solution. The comparisons showed that the solutions are seen to be perfectly compatible. The effects of problem parameters were investigated on the heat transfer rate and fin efficiency and results were presented graphically.

  13. Computational heat transfer analysis and combined ANN–GA optimization of hollow cylindrical pin fin on a vertical base plate

    Indian Academy of Sciences (India)

    C Balachandar; S Arunkumar; M Venkatesan

    2015-09-01

    In the devices like laptops, microprocessors, the electric circuits generate heat while performing work which necessitates the use of fins. In the present work, the heat transfer characteristics of hollow cylindrical pin fin array on a vertical rectangular base plate is studied using commercial CFD code ANSYS FLUENT© . The hollow cylindrical pin fins are arranged inline. The heat transfer augmentation is studied for different parameters such as inner radius, outer radius, height of the fins and number of pin fins. The base plate is supplied with a constant heat flux in the range of 20–500W. The base plate dimensions are kept constant. The base plate temperature is predicted using Artificial Neural Network (ANN) by training the network based on the results of numerical simulation. The trained ANN is used to analyse the fin in terms of enhanced heat transfer and weight reduction when compared to solid pin fin. Optimization of the hollow cylindrical pin fin parameters to obtain maximum heat transfer from the base plate is carried out using Genetic Algorithm (GA) applied on the trained neural network. The analysis using the numerical simulation and neural network shows that the hollow fins provide an increased heat transfer and a weight reduction of about 90% when compared to solid cylindrical pin fins.

  14. Novel concepts and geometries as alternatives to conventional circular pin fins for gas turbine blade cooling applications

    Science.gov (United States)

    Uzol, Oguz

    Short cylindrical pin fins with circular cross-sections are one of the most common types of cooling devices used in turbine blades. However it is by no means clear that the circular shape is the most efficient geometry in terms of heat transfer enhancement and pressure loss minimization. Therefore, novel pin fin concepts and geometries are developed and introduced as alternatives to conventional circular pin fins. The idea of using fluidic oscillators as turbulent heat transfer enhancement devices led to the novel concept of "oscillator fin". Also the idea of using more elliptical fin shapes resulted in the development of the SEF (Standard Elliptical Fin), the N fin (Derived from NACA four-digit series of airfoils) and the Egg fin (A hybrid circular-elliptical fin). Detailed experimental and computational investigations are performed in order to determine the heat transfer and pressure loss characteristics of these new concepts and the results are compared to the characteristics of conventional circular pin fins. The experimental analysis included endwall convective heat transfer coefficient measurements, wake total pressure surveys and wake flow field measurements and visualizations using particle image velocimetry (PIV). The isolated single fin measurements revealed that the oscillator fin concept is not working as expected and does not provide any advantage over circular fins. The SEFs and the N fins were found to be the most effective cooling devices in terms of both heat transfer enhancement and pressure loss minimization. The characteristics of the SEF and N fins are also determined for a 2 row staggered array configuration. It is observed that the endwall heat transfer enhancement capability of the SEFs and the N fins is about 25% less than the circular fins. However these elliptical fins caused tremendous reduction in loss levels from 100% to 200%. The main reason of this high levels of pressure loss in circular fin arrays is determined to be the huge low

  15. HEAT TRANSFER ENHANCEMENT OF SMALL SCALE HEAT SINKS USING VIBRATING PIN FIN

    Directory of Open Access Journals (Sweden)

    Suabsakul Gururatana

    2013-01-01

    Full Text Available Heat sinks are widely adopted in electronics cooling together with different technologies to enhance the cooling process. For the small electronics application, the small scale pin fins heat sinks are extensively used to dissipate heat in electronics devices. Due to the limit of space in the small devices, it is impossible to increase heat transfer area. In order to improve the heat transfer performance, the applying the forced vibration is one of challenging method. This study applies the vibration frequency between 50 to 1,000 Hz to pin fins heat sinks. The results of numerical simulation clearly show satisfied heat transfer augmentation. However, the Pressure drop significantly increases with frequency. This phenomenon affects the heat transfer enhancement performance that it increases with frequency until certain value then it drops rapidly. The results of this study can help designing heat sinks for electronics cooling by employing the concept of vibration.

  16. Boundary element method applied to a gas-fired pin-fin-enhanced heat pipe

    Energy Technology Data Exchange (ETDEWEB)

    Andraka, C.E.; Knorovsky, G.A.; Drewien, C.A.

    1998-02-01

    The thermal conduction of a portion of an enhanced surface heat exchanger for a gas fired heat pipe solar receiver was modeled using the boundary element and finite element methods (BEM and FEM) to determine the effect of weld fillet size on performance of a stud welded pin fin. A process that could be utilized by others for designing the surface mesh on an object of interest, performing a conversion from the mesh into the input format utilized by the BEM code, obtaining output on the surface of the object, and displaying visual results was developed. It was determined that the weld fillet on the pin fin significantly enhanced the heat performance, improving the operating margin of the heat exchanger. The performance of the BEM program on the pin fin was measured (as computational time) and used as a performance comparison with the FEM model. Given similar surface element densities, the BEM method took longer to get a solution than the FEM method. The FEM method creates a sparse matrix that scales in storage and computation as the number of nodes (N), whereas the BEM method scales as N{sup 2} in storage and N{sup 3} in computation.

  17. Numerical study of thermal performance of perforated circular pin fin heat sinks in forced convection

    Science.gov (United States)

    Wen, Mao-Yu; Yeh, Cheng-Hsiung

    2016-12-01

    This paper presents a numerical simulation of the heat transfer performance under forced convection for two different types of circular pin fin heat sinks with (Type A) and without (Type B) a hollow in the heated base. COMSOL Multiphysics, which is used for the thermal hydraulic analyses, has proven to be a powerful finite-element-based simulation tool for solving multiple physics-based systems of partial and ordinary differential equations. The standard κ- ɛ two-equations turbulence model is employed to describe the turbulent structure and behavior. The numerical results are validated with the experimental results, and are shown to be in good agreement. The effects of the Reynolds number, height of the fin, finning factor and the perforated base plate on the heat-transfer coefficient are investigated and evaluated. The present study strongly recommends the use of a small hollow ( (Dh /Db ) sink.

  18. Numerical study of thermal performance of perforated circular pin fin heat sinks in forced convection

    Science.gov (United States)

    Wen, Mao-Yu; Yeh, Cheng-Hsiung

    2017-06-01

    This paper presents a numerical simulation of the heat transfer performance under forced convection for two different types of circular pin fin heat sinks with (Type A) and without (Type B) a hollow in the heated base. COMSOL Multiphysics, which is used for the thermal hydraulic analyses, has proven to be a powerful finite-element-based simulation tool for solving multiple physics-based systems of partial and ordinary differential equations. The standard κ - \\varepsilon two-equations turbulence model is employed to describe the turbulent structure and behavior. The numerical results are validated with the experimental results, and are shown to be in good agreement. The effects of the Reynolds number, height of the fin, finning factor and the perforated base plate on the heat-transfer coefficient are investigated and evaluated. The present study strongly recommends the use of a small hollow ( (Dh /Db ) heat sink.

  19. Heat transfer in thin, compact heat exchangers with circular, rectangular, or pin-fin flow passages

    Science.gov (United States)

    Olson, D. A.

    1992-01-01

    Heat transfer and pressure drop have been measured of three thin, compact heat exchangers in helium gas at 3.5 MPa and higher, with Reynolds numbers of 450 to 36,000. The flow geometries for the three heat exchanger specimens were: circular tube, rectangular channel, and staggered pin fin with tapered pins. The specimens were heated radiatively at heat fluxes up to 77 W/sq cm. Correlations were developed for the isothermal friction factor as a function of Reynolds number, and for the Nusselt number as a function of Reynolds number and the ratio of wall temperature to fluid temperature. The specimen with the pin fin internal geometry had significantly better heat transfer than the other specimens, but it also had higher pressure drop. For certain conditions of helium flow and heating, the temperature more than doubled from the inlet to the outlet of the specimens, producing large changes in gas velocity, density, viscosity, and thermal conductivity. These changes in properties did not affect the correlations for friction factor and Nusselt number in turbulent flow.

  20. Heat transfer and pressure drop in a compact pin-fin heat exchanger with pin orientation at 18 deg to the flow direction

    Science.gov (United States)

    Olson, D. A.

    1991-01-01

    The heat transfer and pressure drop characteristics of a novel, compact heat exchanger in helium gas were measured at 3.5 MPa and Reynolds numbers of 450 to 12,000. The pin-fin specimen consisted of pins, 0.51 mm high and spaced 2.03 mm on centers, spanning a channel through which the helium flows; the angle of the row of pins to the flow direction was 18 deg. The specimen was radiatively heated on the top side at heat fluxes up to 74 W/sq cm and insulated on the back side. Correlations were developed for the friction factor and Nusselt number. The Nusselt number compares favorably to those of past studies of staggered pin-fins, when the measured temperatures are extrapolated to the temperature of the wall-fluid interface.

  1. Low Reynolds number flow in rectangular cooling channels provided with low aspect ratio pin fins

    Energy Technology Data Exchange (ETDEWEB)

    Armellini, Alessandro; Casarsa, Luca [Dipartimento di Energetica e Macchine, Universita di Udine, Via delle Scienze 208, 33100 Udine (Italy); Giannattasio, Pietro, E-mail: pietro.giannattasio@uniud.i [Dipartimento di Energetica e Macchine, Universita di Udine, Via delle Scienze 208, 33100 Udine (Italy)

    2010-08-15

    The flow structures around single heat transfer promoters of different shapes (square, circular, triangular and rhomboidal) have been investigated experimentally by means of a 2-D Particle Image Velocimetry (PIV) technique. The geometrical configuration and flow conditions considered are typical of real liquid cooling channels. They include low aspect ratio pin fins confined at both ends by the walls of a rectangular channel, water flow at low Reynolds numbers (Re = 800, 1800, 2800), high core flow turbulence and undeveloped boundary layers at the position of the obstacle. In front of the pin fins the high turbulence level is found to promote a strong instability of the horseshoe vortex system that forms at the wall/obstacle junction. In particular, frequent events of break-away of the primary vortices and inrush of core fluid, which are known to enhance the wall heat transfer, are observed in the cases of square and circular pins already from Re = 1800. The near wake downstream of the obstacles appears to be influenced by streamwise oriented vortical structures produced at the wall/obstacle junction. They give rise to spanwise velocity components (up-wash flow) that lead to a three-dimensional mass recirculation behind the pins. The combination of up-wash flows, low Reynolds number and high core flow turbulence gives rise to a competition between the classical alternate vortex shedding and an irregular shedding mode characterized by the decoupling of the shear layers and the absence of well organized primary structures. At Re = 800, the irregular shedding prevails and the mean wake topology is almost insensitive to the obstacle shape. As the Reynolds number is increased, the junction flow structures reduce in size and strength, their effect on the wake flow weakens and the recirculation structures behind the obstacles differentiate significantly according to the pin shape. Besides investigating complex flow structures in geometrical and flow configurations of

  2. Boiling heat transfer in a hydrofoil-based micro pin fin heat sink

    Energy Technology Data Exchange (ETDEWEB)

    Kosar, Ali; Peles, Yoav [Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    2007-03-15

    Flow boiling of R-123 in a hydrofoil-based micro pin fin heat sink was investigated. Average two-phase heat transfer coefficients were obtained over effective heat fluxes ranging from 19 to 312 W/cm{sup 2} and mass fluxes from 976 to 2349 kg/m{sup 2} s. The paper presents a flow map, which divides the data into three flow pattern regions: bubbly, wavy intermittent and spray-annular flows. Heat transfer coefficient trends and flow morphologies were used to infer boiling heat transfer mechanisms. Existing conventional scale correlations for circular tubes resulted in large scatter and were not able to predict the heat transfer coefficients accurately. (author)

  3. Simulation of Impinging Cooling Performance with Pin Fins and Mist Cooling Adopted in a Simplified Gas Turbine Transition Piece

    Directory of Open Access Journals (Sweden)

    Tao Xu

    2014-01-01

    Full Text Available The gas turbine transition piece was simplified to a one-four cylinder double chamber model with a single row of impinging holes in the outer wall. Heat transfer augmentation in the coolant chamber was achieved through the use of pin fin structure and mist cooling, which could increase the turbulence and heat transfer efficiency. The present research is focused on heat transfer and pressure characteristics of the impinging cooling in the coolant chamber using FLUENT software. With the given diameter of impinging hole, pin fin diameter ratios D/d have been numerically studied in ranges from 1 to 2. Three different detached L were simulated. The impinging cooling performance in all cases was compared between single-phase and two-phase (imported appropriate mist flow in the coolant chamber. All the simulation results reveal that the factors of L and D/d have significant effects on the convective heat transfer. After the pin fin structure was taken, the resulting temperature decrease of 38.77 K at most compared with the result of structure without pin fins. And with the mist injecting into the cooling chamber, the area weighted average temperature got a lower value without excess pressure loss, which could satisfy the more stringent requirements in engineering.

  4. Absorber Tube with Internal Pin-Fins for Solar Parabolic Trough Collector

    Directory of Open Access Journals (Sweden)

    Kalidasan B.

    2016-01-01

    Full Text Available Solar parabolic trough collectors exploit solar energy for power generation in solar thermal power stations. These systems require long arrays of reflective troughs with absorber tube running along the axis of parabolic dish. A successful attempt to reduce the length of arrays was accomplished by experimentally analysing the modifications done in absorber tube. Two out of three tubes were fabricated and they were employed to obtain the performance parameters through experimentation conducted at VIT University, Vellore, India. Distilled water was used as the working fluid. Maximum efficiency of 39.12% was obtained at 451.6 W/m2 of direct normal irradiance (DNI for absorber tube with internal pin-fins and without glass tube (AFWGt compared to 8.15% obtained at same value of DNI and other conditions for simple absorber tube without glass cover (AWGt. Cylindrical parabolic trough available at the university was utilized, providing the basis for designing and fabrication of the tubes. Plots for varying mass flow rate at interval of 10 minutes were made against instantaneous thermal efficiency and heat utilized, for direct normal irradiance vs. temperature difference across the tubes and instantaneous thermal efficiency. Through the experimentation conducted, better performance was procured compared to earlier works. Thus, the proposal infers that absorber tube with internal fins has good scope for its application, both domestically as well as industrially. It also calls for further research and development of proposed techniques so as to achieve better performance curves.

  5. Flux pinning effect of cubic equiaxed morphology and its Ti stabilizing in Nb3Sn superconductors

    Institute of Scientific and Technical Information of China (English)

    Andre; SULPICE; Jean-Louis; SOUBEYROUX; Christophe; VERWAERDE; Gia; Ky; HOANG

    2009-01-01

    Two sets of internal-Sn Nb3Sn superconducting strands were fabricated through RRP method, one with 2 wt% of Ti alloyed in Sn core and the other just pure Sn. Four reaction temperatures of 650℃, 675℃, 700℃ and 725℃ and 128 h duration were applied for A15 phase formation heat treatment after Cu-Sn alloying procedure of 210℃/50 h + 340℃/25 h. For the heat-treated coil samples, transport non-Cu JC was examined through standard 4-probe technique and phase microstructure was observed by means of Field Emission Scanning Electronic Microscope (FESEM). The obtained results demonstrate that the transport critical current density JC of Nb3Sn superconductors is more importantly determined by the cubic equiaxed crystalline morphology than by grain size. Ti addition in Sn stabilizes the cubic equiaxed phase at lower temperature so that heat reaction temperature is effectively reduced, the flux pinning performance is largely reinforced and the transport critical current density JC is substantially promoted.

  6. Pressure Drop and Catalytic Dehydrogenation of NaBH{sub 4} Solution Across Pin Fin Structures in a Microchannel Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Ki Moon [Korea Institute of Industrial Technology, Cheonan (Korea, Republic of); Choi, Seok Hyun [Key Valve Technologies Ltd., Siheung (Korea, Republic of); Lee, Hee Joon [Kookmin Univ., Seoul (Korea, Republic of)

    2017-06-15

    Dehydrogenation from the hydrolysis of a sodium borohydride (NaBH{sub 4}) solution has been of interest owing to its high theoretical hydrogen storage capacity (10.8 wt.%) and potentially safe operation. An experimental study has been performed on the catalytic reaction rate and pressure drop of a NaBH4 solution over both a single microchannel with a hydraulic diameter of 300 μm and a staggered array of micro pin fins in the microchannel with hydraulic diameter of 50 μm. The catalytic reaction rates and pressure drops were obtained under Reynolds numbers from 1 to 60 and solution concentrations from 5 to 20 wt.%. Moreover, reacting flows were visualized using a high-speed camera with a macro zoom lens. As a result, both the amount of hydrogenation and pressure drop are 2.45 times and 1.5 times larger in a pin fin microchannel array than in a single microchannel, respectively.

  7. Investigation of RANS Model Deficiencies for Flow and Heat Transfer Simulations in a Pin-Fin Array

    Science.gov (United States)

    Hao, Zengrong; Gorle, Catherine; Civil; Environmental Engineering Department Team

    2016-11-01

    Quantifying turbulence model-form uncertainties of Reynolds-averaged Navier-Stokes (RANS) models is a challenging topic, largely because model inaccuracies can vary greatly across flow regions. The objective of the present study is to gain knowledge on where and how RANS models violate reality in representative heat exchanger geometries, such that a UQ method for use in optimization studies can be developed. To achieve this objective we performed a large-eddy simulation (LES) of the flow and heat transfer for a pin-fin array, and analyzed where RANS fails to predict the key features. The LES results are validated against experimental data available from Ames et al. (J. Turbo., 2005) and Ames and Dvorak (J. Turbo., 2006). The RANS simulations showed significant deviations from the LES for mean velocity profiles downstream of certain pins and for the Nusselt number distribution on the fins. A detailed comparison of the turbulent quantities illustrates a general underestimation of the Reynolds stresses and turbulent heat fluxes in near-fin regions, and incorrect trends in some pin-wake regions near the channel center plane. Based on this analysis, we draw conclusions that will support the development of a turbulence model UQ method for heat exchangers. This work is supported by IWT SBO project EUFORIA.

  8. Thermal management optimization of an air-cooled Li-ion battery module using pin-fin heat sinks for hybrid electric vehicles

    Science.gov (United States)

    Mohammadian, Shahabeddin K.; Zhang, Yuwen

    2015-01-01

    Three dimensional transient thermal analysis of an air-cooled module that contains prismatic Li-ion cells next to a special kind of aluminum pin fin heat sink whose heights of pin fins increase linearly through the width of the channel in air flow direction was studied for thermal management of Lithium-ion battery pack. The effects of pin fins arrangements, discharge rates, inlet air flow velocities, and inlet air temperatures on the battery were investigated. The results showed that despite of heat sinks with uniform pin fin heights that increase the standard deviation of the temperature field, using this kind of pin fin heat sink compare to the heat sink without pin fins not only decreases the bulk temperature inside the battery, but also decreases the standard deviation of the temperature field inside the battery as well. Increasing the inlet air temperature leads to decreasing the standard deviation of the temperature field while increases the maximum temperature of the battery. Furthermore, increasing the inlet air velocity first increases the standard deviation of the temperature field till reaches to the maximum point, and after that decreases. Also, increasing the inlet air velocity leads to decrease in the maximum temperature of the battery.

  9. A Taguchi approach for determination of optimum design parameters for a heat exchanger having circular-cross sectional pin fins

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Bayram [Ataturk University, Department of Mechanical Engineering, Faculty of Engineering, Erzurum (Turkey)

    2007-03-15

    The present work submits an investigation about the optimal values of design parameters and performance analysis for a heat exchanger having cylindrical pin fins positioned in a rectangular channel. The experiments covered the following range: Reynolds number 13,500-42,000, the clearance ratio (C/H) 0, 0.33 and 1, the interfin spacing ratio (S{sub y} /D) 1.208, 1.944 and 3.417. In the experimentation, Taguchi method was employed, and Nusselt number and friction factor were considered as performance parameters. While the optimum parameters were determined, due to the goals (above aims) more than one being, the trade-off among goals was considered. First of all, each goal was optimized, separately. Then, all goals were optimized together, considering the priority of goals, and the optimum results were found to be Reynolds number of 42,000, fin height of 50 mm and pitch of 3.417. The performance analysis also was made under a constant pumping power constraint, and the results showed that the use of cylindrical pin fins may lead to an advantage on the basis of heat transfer enhancement. (orig.)

  10. Thermal and Fluid Dynamic Performance of Pin Fin Heat Transfer Surfaces

    OpenAIRE

    Sahiti, Naser

    2006-01-01

    This thesis is organized into nine Chapters. Chapter 2 gives an overview of some highly effec-tive heat transfer surfaces used basically for the enhancement of single-phase convective heat transfer in the air conditioning, refrigeration, unit air heater and automobile industries. It follows the analysis of basic parameters that influence the performance of the fins and at the end a rela-tively simple analytical method for the assessment of the order of the magnitude of heat transfer enhanceme...

  11. 针翅管传热与压降特性研究%Research on Heat Transfer and Pressure Drop Characteristics of Integral Pin-Fin Tube

    Institute of Scientific and Technical Information of China (English)

    石帅; 阎昌琪; 牛广林; 陈哲雨

    2012-01-01

    以润滑油为换热介质,对整体针翅管传热与阻力特性进行了理论分析与试验研究,研究结果可为针翅管的优化设计提供参考.在换热介质纵向冲刷换热管的条件下,对不同针翅长度的3种整体针翅管与光管进行了传热与阻力试验.结果表明:整体针翅管对润滑油换热具有很好的强化能力,在本试验范围内,整体针翅管对油流体扰动强烈,换热强度是同条件下光管的2~6倍;针翅长度是影响针翅管压降的主要因素,在雷诺数达300时,压降曲线出现转折.%Taking lubricating oil as the heat transfer medium, heat transfer and pressure drop characteristics of integral pin-fin tubes were researched both in terms of theoretical and experiments. The results can provide a reference for pin-fin tube optimization. Under the condition of heat transfer medium longitudinally flushing the heat exchanger tube surface, the heat transfer and resistance experiments of plain tube and integral pin-fin tubes (in three different length) were carried out in the present work. The results show that the integral pin-fin tubes can improve the heat transfer ability of lubricating oil. The oil flow fluctuation caused by integral pin-fin tubes is intense and the heat transfer intension of integral pin-fin tubes is 2-6 times of plain tube at the same experiment condition. The length of fin makes main influence on pressure drop, and the pressure drop curve turns around when the values of Reynolds number reaches to 300.

  12. Flow and Heat Transfer in Micro Pin Fin Heat Sinks with Nano-Encapsulated Phase Change Materials

    CERN Document Server

    Rajabifar, Bahram; Zhang, Yuwen; Khanna, Sanjeev K

    2016-01-01

    In this paper, a 3D conjugated heat transfer model for Nano-Encapsulated Phase Change Materials (NEPCMs) cooled Micro Pin Fin Heat Sink (MPFHS) is presented. The governing equations of flow and heat transfer are solved using a finite volume method based on collocated grid and the results are validated with the available data reported in the literature. The effect of nanoparticles volume fraction (C = 0.1, 0.2, 0.3), inlet velocity (Vin = 0.015, 0.030, 0.045 m/s), and bottom wall temperature (Twall = 299.15, 303.15, 315.15, 350.15 K) are studied on Nusselt and Euler numbers as well as temperature contours in the system. The results indicate that significant heat transfer enhancement is achieved when using NEPCM slurry as an advanced coolant. The maximum Nusselt number when NEPCM slurry (C = 0.3) with Vin = 0.015, 0.030, 0.045 (m/s) is employed, are 2.27, 1.81, 1.56 times higher than the ones with base fluid, respectively. However, with increasing bottom wall temperature, the Nusselt number first increases then...

  13. Benchmarking the Performance of the ANSYS-FLUENT Standard k- ε Turbulence Model in Fluid Flow and Heat Transfer Predictions for Complex Flows around Circular Pin-Fins Using Various near Wall Functions

    Directory of Open Access Journals (Sweden)

    A. Al-Witry

    2013-05-01

    Full Text Available This study compares CFD analyses of the fluid flow and heat transfer phenomena in a popular pin-fin geometry of X/D = 2.5, S/D = 2.5 and H/D = 1 for a range of Re = 5,000 to 30,000 to those from experiment to aid in the benchmarking the performance of the CFD code FLUENT. The CFD analyses use three ANSYS-FLUENT (version 13 near wall treatments available within the code: 1 the Standard Wall Function (SWF, 2 the Non-Equilibrium Wall Function (NEWF and 3 the enhanced wall treatment. Experimental data used in this study were obtained from two papers: 1 by Chyu et al. (1998 for heat transfer predictions and another 2 by Metzgeret al. (1984 for pressure loss predictions, both for the same setup. The study also differentiates between the heat transfer occurring by the body of the pin-fin itself and that by the end-wall areas surrounding it. Results from the CFD analyses based on the fourth pin-fin from the inlet (commonly assumed to have a stable flow around it, show very good prediction accuracies of heat transfer coefficients for the pin-fin body itself but rather low accuracies for the end-wall areas (based on heat flux and inlet temperature values. Better accuracies were obtained when using the enhanced wall treatment where pin-fin body heat transfer coefficients were almost identical between the CFD and experimental results. An alternative definition of heat transfer based on the averaged local temperatures around the fourth pin-fin showed that the heat transfer coefficient then (with CFD's capability to establish the local thermal field is really between 1.5 to 3.5 times that predicted by using the inlet temperature in deducing the local h values. The same accuracies cannot be said about its predictions of pressure loss coefficients where CFD results tended to be lower by 50-100%h.

  14. Experimental Study on the Resistance Characteristics of Forced Convection in Pin-Fin Casing%针翅套管内强迫流动阻力特性试验研究

    Institute of Scientific and Technical Information of China (English)

    王明新

    2014-01-01

    A study is conducted on the resistance characteristic of forced convection in pin-fin casing, where both lubricants and water are used as test fluids. The effects of height and pitch of the pin-fin on the resistance coefficient are presented accordingly. The results show that the flow resistance characteristics of pin-fin casing annulus are quite different from that for both conventional circular tubes and smooth tube annulus. Particularly, the fluid in the annular space is significantly disturbed by pin-fin, the relative height of which exerts great impacts on the transition of fluid state. Also,the correlation of the frictional pressure drop is calculated by introducing the mass velocity and structural parameters of pin-fin tubes based upon experi-mental data,which facilitates further discussion on the resistance characteristic of pin-fin casing annulus.%以润滑油-水为工质,对针翅套管双侧强迫流动的阻力特性进行试验研究,分析针翅相对高度与针翅管节距等因素对流动阻力系数的影响。结果发现,针翅套管环隙内的流动阻力特性与普通圆管以及光滑管环隙大不相同。由于其环隙内布满针翅,对流体产生了极大的扰动,因此对流体流态的转变有重要影响,其中相对翅高的影响较大。在对试验数据进行分析整理的基础上,回归出摩擦阻力压降与质量流速和针翅管结构参数的试验关联式。

  15. PLC在钉头管埋弧螺柱焊中的应用%The Application of Programmable Logical Controller (PLC) in Submerged Arc Stud Welding for Pin Finned Tube

    Institute of Scientific and Technical Information of China (English)

    周拨云; 梅强

    2011-01-01

    In order to accurately control pin finned tube welding procedure, the PLC was applied into the control of pin finned tube submerged arc stud welding. This article introduced SSAW for pin finned tube composition and control requirements of welding control system, this system selected Emerson EC10-2416BTA programmable logical controller, adopted Emerson Control Start software to workout control procedure, and realized automatic welding for pin finned tube submerged arc stud welding. This system is with high efficiency energy saving, it overcomes some disadvantages of manual welding,such as great labour intensity,bad quality of welding joints and low welding efficiency,at the same time, this system can identify failure, alarm and timely deal with, so it can ensure stable welding quality.%为了对钉头管焊接过程进行精确控制,将PLC应用于钉头管埋弧螺柱焊焊接控制.介绍了钉头管埋弧螺柱焊焊接控制系统的组成及控制要求,选用了艾默生EC10-2416BTA型可编程控制器,采用艾默生编程软件Control Start编制控制程序,实现了钉头管埋弧螺柱焊的自动化焊接.该系统高效节能,并克服了手工焊劳动强度大、接头质量差、焊接效率低等缺点,具有故障诊断和报警功能,并作出相应的处理,保证稳定焊接质量.

  16. Experimental Research on Flow and Heat Transfer Characteristic in Pin Fin Passage with Double-Inlet%双向进气时扰流柱通道内流动与换热特性试验研究

    Institute of Scientific and Technical Information of China (English)

    任芳; 潘炳华; 郭文; 朱惠人

    2013-01-01

    The tests were carried out to study the heat transfer characteristic of the pin fin at the turbine blade trailing edge in the double-inlet case. The test model of turbine blade trailing edge rib and pin fin were simplified and magnified four times so to keep the basic characteristics of trailing edge. Pressure distri⁃bution and Nusselt number distribution at measuring points were obtained through regulating flow between pin fin passage and rib passage. The results showed that, with double-inlet structure, the distribution of pressure and heat transfer were relatively uniform , and the problem of poor heat transfer in blade tip caused by large resistance of flow and much pressure loss in pin fin passage with one inlet was conquered.%  试验研究了两端进气时涡轮叶片尾缘扰流柱通道内的流动与换热特性。试验模型对涡轮叶片尾缘横肋、扰流柱通道进行了简化,并放大四倍,保留了叶片尾缘的基本特征。试验中通过调节扰流柱通道和横肋通道的流量分配,得到各测点的压力分布和努赛尔数据分布。研究结果表明,扰流柱通道两端进气结构,使整个通道的压力分布和换热分布比较均匀,克服了一端进气时流阻和压力损失较大引起的叶尖换热较差的缺点。

  17. Experimental Study of Heat Transfer and Pressure Drop Characteristics on Shell-side of Pin-fin Tube Oil Cooler%针翅管滑油冷却器壳侧传热与阻力性能实验研究

    Institute of Scientific and Technical Information of China (English)

    石帅; 阎昌琪; 丁铭

    2013-01-01

    The comparative experimental study for one smooth tube oil cooler and three pin-fin tube oil coolers was performed by using lubricating oil as heat transfer medium . The experimental results indicate that in the range of experimental study ,total heat transfer coefficient of pin-fin tube oil coolers is about 1.4-2 times higher than that of the smooth tube oil cooler .The heat transfer and pressure drop characteristics are greatly different for different structures of pin-fin tube oil coolers .T he effects of the structure of pin-fin tube and shell-side flow path number are dominant to influence heat transfer and pressure drop characteristics of oil coolers . In the range of experimental study , large pin-fin height is conducive to the oil flow disturbance ,but not conducive to the heat transfer on the tube-base heat transfer surface of pin-fin tube;single-pass pin-fin tube oil cooler offers high total heat transfer coefficient and volumetric heat transfer capacity ,the global heat transfer performance and the friction characteristics are better than that of two-pass pin-fin tube oil cooler .%以润滑油为换热介质,对1个光管滑油冷却器和3个采用了针翅管的滑油冷却器实验体进行了对比实验研究。结果表明:在本实验范围内,针翅管滑油冷却器的总传热系数较高,是相同条件下光管滑油冷却器总传热系数的1.4~2倍;不同结构针翅管滑油冷却器的传热与阻力性能差别较大,针翅管结构参数和壳侧流程数目是影响滑油冷却器壳程传热与阻力性能的主要因素。实验范围内,较大的针翅高度有利于油流体的扰动,但不利于针翅管一次传热面处的换热;单流程结构的针翅管滑油冷却器具有较高的传热系数和单位体积换热量,其总体换热性能与阻力性能优于双流程结构的针翅管滑油冷却器。

  18. Blower Cooling of Finned Cylinders

    Science.gov (United States)

    Schey, Oscar W; Ellerbrock, Herman H , Jr

    1937-01-01

    Several electrically heated finned steel cylinders enclosed in jackets were cooled by air from a blower. The effect of the air conditions and fin dimensions on the average surface heat-transfer coefficient q and the power required to force the air around the cylinders were determined. Tests were conducted at air velocities between the fins from 10 to 130 miles per hour and at specific weights of the air varying from 0.046 to 0.074 pound per cubic foot. The fin dimensions of the cylinders covered a range in pitches from 0.057 to 0.25 inch average fin thicknesses from 0.035 to 0.04 inch, and fin widths from 0.67 to 1.22 inches.

  19. Influence of face-centered-cubic texturing of Co2Fe6B2 pinned layer on tunneling magnetoresistance ratio decrease in Co2Fe6B2/MgO-based p-MTJ spin valves stacked with a [Co/Pd](n)-SyAF layer.

    Science.gov (United States)

    Takemura, Yasutaka; Lee, Du-Yeong; Lee, Seung-Eun; Chae, Kyo-Suk; Shim, Tae-Hun; Lian, Guoda; Kim, Moon; Park, Jea-Gun

    2015-05-15

    The TMR ratio of Co2Fe6B2/MgO-based p-MTJ spin valves stacked with a [Co/Pd]n-SyAF layer decreased rapidly when the ex situ magnetic annealing temperature (Tex) was increased from 275 to 325 °C, and this decrease was associated with degradation of the Co2Fe6B2 pinned layer rather than the Co2Fe6B2 free layer. At a Tex above 325 °C the amorphous Co2Fe6B2 pinned layer was transformed into a face-centered-cubic (fcc) crystalline layer textured from [Co/Pd]n-SyAF, abruptly reducing the Δ1 coherence tunneling of perpendicular-spin-torque electrons between the (100) MgO tunneling barrier and the fcc Co2Fe6B2 pinned layer.

  20. Heat transfer of sub-merged jet impingement on pin-fin heat sinks with silver nanofluid%Ag纳米流体浸没射流冲击换热特性

    Institute of Scientific and Technical Information of China (English)

    夏国栋; 周明正; 周利军; 崔珍珍; 杨瑞波

    2011-01-01

    Silver-water nanofluid, used as the working fluid in this study, was prepared in one step employing ultrasound-assisted membrane reaction. The heat transfer of submerged jet impacting pin-fin heat sinks was investigated experimentally with silver nanofluid of different concentrations. The results indicate that the silver nanoparticles prepared are uniformly distributed in base fluid and with an average grain size of 4.8 nm. The surfactant used in this study has great influence on the viscosity of nanofluids. Compared with the base fluid (water and surfactant), the heat transfer coefficient of nanofluids is increased by 6.23%, 9.24% and 17. 53%, respectively, with the silver nanoparticle mass fraction of 0.02%, 0.08% and 0. 12%, under the same jet velocity. Compared with water, the heat transfer coefficient is enhanced by 6. 61% with the silver nanoparticle of 0.12%.%采用超声膜扩散法一步制备出水基Ag纳米流体作为实验工质,并对不同质量分数的Ag纳米流体在受限浸没阵列射流冲击针肋热沉中的流动和换热特性进行了实验研究.结果表明:采用超声膜扩散法制备的Ag纳米颗粒粒径分布均匀,平均粒径只有4.8 nm;表面活性剂对纳米流体的黏度影响较大;相同射流速度下,与基液(水+表面活性剂)相比,Ag粒子质量分数分别为0.02%、0.08%、0.12Z的纳米流体传热系数分别提高6.23%、9.24%、17.53Z;与纯水相比,Ag粒子质量分数为0.12%时,纳米流体传热系数增加6.61%.

  1. Happy Pinning

    DEFF Research Database (Denmark)

    Fausing, Bent

    2012-01-01

    This is about Pinterest, but with a different approach than usual to social networks. Pinterest is an image site par excellence. The images are as Windows that open outwards and also lets us look inwards and displays the soul and heart, the unintentional or pre-conscious desires. Happy Pinning!...

  2. Happy Pinning

    DEFF Research Database (Denmark)

    Fausing, Bent

    2012-01-01

    This is about Pinterest, but with a different approach than usual to social networks. Pinterest is an image site par excellence. The images are as Windows that open outwards and also lets us look inwards and displays the soul and heart, the unintentional or pre-conscious desires. Happy Pinning!...

  3. FIN 403 UOP Course Tutorial / fin403dotcom

    OpenAIRE

    anil10

    2015-01-01

    FIN 403 Entire Course For more course tutorials visit www.fin403.com   FIN 403 Week 1 Individual Assignment Global Finance Environment Paper FIN 403 Week 1 DQ 1 FIN 403 Week 1 DQ 2 FIN 403 Week 1 Summary FIN403 Week 2 Learning Team Assignment Investment Decision Selection Paper   FIN 403 Week 2 DQ 1 FIN 403 Week 2 DQ 2 FIN 403 Week 2 Summary FIN 403 Week 3 Learning Team Assignment Foreign Exchange and Derivatives Market Paper F...

  4. FIN 403 Uop Material-fin403dotcom

    OpenAIRE

    Sandywilliam8

    2015-01-01

    FIN 403 Entire Course For more course tutorials visit www.fin403.com   FIN 403 Week 1 Individual Assignment Global Finance Environment Paper FIN 403 Week 1 DQ 1 FIN 403 Week 1 DQ 2 FIN 403 Week 1 Summary FIN403 Week 2 Learning Team Assignment Investment Decision Selection Paper   FIN 403 Week 2 DQ 1 FIN 403 Week 2 DQ 2 FIN 403 Week 2 Summary FIN 403 Week 3 Learning Team Assignment Foreign Exchange and Derivatives Market Paper F...

  5. Performance Evaluation of Plate-Fin-And Tube Heat Exchanger with Wavy Fins- A Review

    Directory of Open Access Journals (Sweden)

    Sandip S. Kale

    2014-09-01

    Full Text Available The plate fin-and-tube heat exchangers are widely used in variety of industrial applications, particularly in the heating, air-conditioning and refrigeration, HVAC industries. In most cases the working fluid is liquid on the tube side exchanging heat with a gas, usually air. It is seen that the performance of heat exchangers can be greatly increased with the use of unconventionally shaped flow passages such as plain, perforated offset strip, louvered, wavy, vortex generator and pin. The current study is focused on wavy-fin. The wavy surface can lengthen the path of airflow and cause better airflow mixing. In order to design better heat exchangers and come up with efficient designs, a thorough understanding of the flow of air in these channels is required. Hence this study focuses on the heat transfer and friction characteristics of the air side for wavy fin and tube heat exchanger.

  6. Pediatric safety pin ingestion.

    Science.gov (United States)

    Sarihan, H; Kaklikkaya, I; Ozcan, F

    1998-08-01

    Fifteen consecutive children with ingested safety pins were evaluated retrospectively. Eight patients were males and seven were girls. The mean age of the patients was 5.4 years ranging from 7 months to 16 years. Two of 15 patients were mentally retarded Seven safety pins ingestion were noted by parents, three older children applied with safety pin swallowing. Three infants referred with hypersalivation and swallowing difficulty. One of two mentally retarded patients had recurrent aspiration pneumonia, the other had neck abscess. These patients' lesions were detected incidentally by thoracic X-ray. Nine safety pins were at the level of the cricopharyngeus, one at the level of the aortic arch and five at the esophagogastric junction. A right esophagoscopy was used for extraction of safety pins under general anesthesia and endotracheal intubation were used. Before esophagoscopy control plain X-ray was obtained for location of safety pin. Nine safety pins were extracted by esophagoscopy. Three safety pins spontaneously and three during anesthesia induction passed through the esophagus falling down the stomach. Five of these six safety pins were spontaneously extracted without complication. However one open safety pin lodged at the duodenum and laparotomy was required. In this article, etiology and management of safety pin ingestion in children are discussed.

  7. Shark's Fin Soup

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Ingredients: 250g semi-finished shark's fin (removed of bone, skin and dipped in water), 100g ham, 100g chicken, 50g pork shoulder, 50g dried scallops, 100g bean sprouts, salt and MSG (optional). Method: 1. Scald the shark's fin in boiling water. 2. Fill a pot with water and add the chicken, pork and most of the

  8. Comparative Study for Improving the Thermal and Fluid Flow Performance of Micro Channel Fin Geometries Using Numerical Simulation

    Directory of Open Access Journals (Sweden)

    S.Subramanian

    2015-07-01

    Full Text Available There is a continuous quest for improving the performance of micro channels for handling the increased dissipation of heat from electronics circuits. The Oblique fin micro channels are attractive as they perform better than plate fin & pin fin configurations. There are scopes for further improvements in oblique fin micro channels. Hence this work is about the investigation for the performance enhancement by modifying the oblique fin geometry. Seven variants of micro channel geometries have been explored using three dimensional numerical simulations. The variants are plate fin, in-line pin fin, staggered pin fin, oblique fin, oblique fin with two slit angles, oblique with nozzle type slit and improved oblique fin. The simulation results are validated using the published data. To ensure a common reference for comparison, hydraulic diameter, inlet flow conditions, heat loads and the boundary conditions are kept identical across all the geometries. The results of simulation are compared for the thermal & fluid flow performances. Heat transfer correlations have been developed using the simulation data. The proposed modification is found to enhance the performance significantly

  9. Experimental Analysis Of Heat Transfer From Square Perforated Fins In Staggered Arrangement

    Directory of Open Access Journals (Sweden)

    Siddiqui. M. Abdullah

    2015-08-01

    Full Text Available This project gives the experimental analysis of heat transfer over a flat surface equipped with Square perforated pin fins in staggered arrangement in a rectangular channel. The Fin dimensions are 100mm in height & 25mm in width. The range of Reynolds number is fixed & about 13,500– 42,000, the clearance ratio (C/H 0, 0.33 and 1, the inter-fin spacing ratio (Sy /D 1.208, 1.524, 1.944 and 3.417. Sy i.e. stream wise distance is varies and Sx i.e. span wise distance is constant. The friction factor, enhancement efficiency and heat transfer correlate in equations with each other. Here we are comparing Square pin fins with cylindrical pin fins. Staggered arrangement and perforation will enhance the heat transfer rate. Clearance ratio and inter-fin spacing ratio affect on Enhancement efficiency. Both lower clearance ratio and lower inter-fin spacing ratio and comparatively lower Reynolds number give higher thermal performance. Friction factor & Nusselt number are Key parameter which relates with efficiency enhancement and heat transfer rate.

  10. PINS Spectrum Identification Guide

    Energy Technology Data Exchange (ETDEWEB)

    A.J. Caffrey

    2012-03-01

    The Portable Isotopic Neutron Spectroscopy—PINS, for short—system identifies the chemicals inside munitions and containers without opening them, a decided safety advantage if the fill chemical is a hazardous substance like a chemical warfare agent or an explosive. The PINS Spectrum Identification Guide is intended as a reference for technical professionals responsible for the interpretation of PINS gamma-ray spectra. The guide is divided into two parts. The three chapters that constitute Part I cover the science and technology of PINS. Neutron activation analysis is the focus of Chapter 1. Chapter 2 explores PINS hardware, software, and related operational issues. Gamma-ray spectral analysis basics are introduced in Chapter 3. The six chapters of Part II cover the identification of PINS spectra in detail. Like the PINS decision tree logic, these chapters are organized by chemical element: phosphorus-based chemicals, chlorine-based chemicals, etc. These descriptions of hazardous, toxic, and/or explosive chemicals conclude with a chapter on the identification of the inert chemicals, e.g. sand, used to fill practice munitions.

  11. Cubic Subalgebras and Cubic Closed Ideals of B-algebras

    Directory of Open Access Journals (Sweden)

    Tapan Senapati

    2015-06-01

    Full Text Available In this paper, the concept of cubic set to subalgebras, ideals and closed ideals of B-algebras are introduced. Relations among cubic subalgebras with cubic ideals and cubic closed ideals of B-algebras investigated. The homomorphic image and inverse image of cubic subalgebras, ideals are studied and some related properties are investigated. Also, the product of cubic B-algebras are investigated.

  12. Experimental Research on Heat Transfer and Pressure Drop of Two Configurations of Pin Finned—Tubes in an In—line Array

    Institute of Scientific and Technical Information of China (English)

    ShouGuangYao; DeShuZhu

    1994-01-01

    In this paper,a local simulation method is employed to investigate the heat transfer and pressure drop characteristics of two configurations of pin finned tubes deployed in an in-line array,In this research,heat pipes are adopted as heating elements.Therefore,the experimental equipment becomes simple and has an advantage of sufficient reducibility.The air-side heat transfer and pressure drop correlations for each type of pin fin surface including the effect of the tube-row number are obtained in the Reynolds number range commonly encountered in engineering.These correlations may be used in the design of pin finned tube heat exchangers.

  13. Fluid-cooled heat sink with improved fin areas and efficiencies for use in cooling various devices

    Science.gov (United States)

    Bharathan, Desikan; Bennion, Kevin; Kelly, Kenneth; Narumanchi, Sreekant

    2015-04-21

    The disclosure provides a fluid-cooled heat sink having a heat transfer base and a plurality of heat transfer fins in thermal communication with the heat transfer base, where the heat transfer base and the heat transfer fins form a central fluid channel through which a forced or free cooling fluid may flow. The heat transfer pins are arranged around the central fluid channel with a flow space provided between adjacent pins, allowing for some portion of the central fluid channel flow to divert through the flow space. The arrangement reduces the pressure drop of the flow through the fins, optimizes average heat transfer coefficients, reduces contact and fin-pin resistances, and reduces the physical footprint of the heat sink in an operating environment.

  14. Flux pinning in superconductors

    CERN Document Server

    Matsushita, Teruo

    2014-01-01

    The book covers the flux pinning mechanisms and properties and the electromagnetic phenomena caused by the flux pinning common for metallic, high-Tc and MgB2 superconductors. The condensation energy interaction known for normal precipitates or grain boundaries and the kinetic energy interaction proposed for artificial Nb pins in Nb-Ti, etc., are introduced for the pinning mechanism. Summation theories to derive the critical current density are discussed in detail. Irreversible magnetization and AC loss caused by the flux pinning are also discussed. The loss originally stems from the ohmic dissipation of normal electrons in the normal core driven by the electric field induced by the flux motion. The readers will learn why the resultant loss is of hysteresis type in spite of such mechanism. The influence of the flux pinning on the vortex phase diagram in high Tc superconductors is discussed, and the dependencies of the irreversibility field are also described on other quantities such as anisotropy of supercondu...

  15. Flux Pinning in Superconductors

    CERN Document Server

    Matsushita, Teruo

    2007-01-01

    The book covers the flux pinning mechanisms and properties and the electromagnetic phenomena caused by the flux pinning common for metallic, high-Tc and MgB2 superconductors. The condensation energy interaction known for normal precipitates or grain boundaries and the kinetic energy interaction proposed for artificial Nb pins in Nb-Ti, etc., are introduced for the pinning mechanism. Summation theories to derive the critical current density are discussed in detail. Irreversible magnetization and AC loss caused by the flux pinning are also discussed. The loss originally stems from the ohmic dissipation of normal electrons in the normal core driven by the electric field induced by the flux motion. The readers will learn why the resultant loss is of hysteresis type in spite of such mechanism. The influence of the flux pinning on the vortex phase diagram in high Tc superconductors is discussed, and the dependencies of the irreversibility field are also described on other quantities such as anisotropy of supercondu...

  16. CFD modeling of heat transfer in a rectangular channel with dimplepin finning

    Directory of Open Access Journals (Sweden)

    Spokoiny M. Yu.

    2013-05-01

    Full Text Available Using the CFD modeling method, the authors have investigated conjugate heat transfer in a rectangular channel with dimple-pin finning with hight of pins, depth of cavities and Reynolds number values varying in the range, characteristic for heat exchangers designed for liquid cooling of microelectronic devices, such as microprocessors. Criterion dependencies for calculation of heat transfer under these conditions have been obtained.

  17. Fin Distance Effect at Tube-Fin Heat Exchanger

    Science.gov (United States)

    Lemfeld, F.; Muller, M.; Frana, K.

    2013-04-01

    Article deals with numerical simulation of the Tube-Fin heat exchanger. Several distances between fins are examined with intence of increasing the cooling output of the heat exchanger. Geometrical model consists of set of 2 fins with input and output area. Calculations covers the area of the gap from 2.25 mm to 4 mm with new fin geometry. For the numerical silumation was used software Ansys Fluent.

  18. Fin Distance Effect at Tube-Fin Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Frana K.

    2013-04-01

    Full Text Available Article deals with numerical simulation of the Tube-Fin heat exchanger. Several distances between fins are examined with intence of increasing the cooling output of the heat exchanger. Geometrical model consists of set of 2 fins with input and output area. Calculations covers the area of the gap from 2.25 mm to 4 mm with new fin geometry. For the numerical silumation was used software Ansys Fluent.

  19. Extending Fin Concept for a 105-mm Fin Stabilized Projectile

    Science.gov (United States)

    2011-04-01

    more demand for precision guided munitions. The complexity of combat in urban settings requires novel fighting techniques and strategies; driving...fins in the stowed configuration deployment, the fin hubs (6) will rotate forward until they contact the spacer (3). At this point, the fins (7) cock

  20. Einsteinian cubic gravity

    Science.gov (United States)

    Bueno, Pablo; Cano, Pablo A.

    2016-11-01

    We drastically simplify the problem of linearizing a general higher-order theory of gravity. We reduce it to the evaluation of its Lagrangian on a particular Riemann tensor depending on two parameters, and the computation of two derivatives with respect to one of those parameters. We use our method to construct a D -dimensional cubic theory of gravity which satisfies the following properties: (1) it shares the spectrum of Einstein gravity, i.e., it only propagates a transverse and massless graviton on a maximally symmetric background; (2) it is defined in the same way in general dimensions; (3) it is neither trivial nor topological in four dimensions. Up to cubic order in curvature, the only previously known theories satisfying the first two requirements are the Lovelock ones. We show that, up to cubic order, there exists only one additional theory satisfying requirements (1) and (2). Interestingly, this theory is, along with Einstein gravity, the only one which also satisfies (3).

  1. PINS-3X Operations

    Energy Technology Data Exchange (ETDEWEB)

    E.H. Seabury

    2013-09-01

    Idaho National Laboratory’s (INL’s) Portable Isotopic Neutron Spectroscopy System (PINS) non-intrusively identifies the chemical fill of munitions and sealed containers. The PINS-3X variant of the system is used to identify explosives and uses a deuterium-tritium (DT) electronic neutron generator (ENG) as the neutron source. Use of the system, including possession and use of the neutron generator and shipment of the system components requires compliance with a number of regulations. This report outlines some of these requirements as well as some of the requirements in using the system outside of INL.

  2. Diffusion inspires selection of pinning nodes in pinning control

    Science.gov (United States)

    Zhou, Ming-Yang; He, Xingsheng; Fu, Zhong-Qian; Liao, Hao; Cai, Shi-min; Zhuo, Zhao

    2016-03-01

    The outstanding problem of controlling a complex network via pinning is related to network dynamics and has the potential to master large-scale real-world systems as well. This paper addresses the heart issue about how to choose pinning nodes for pinning control, where pinning control aims to control a network to an identical state by injecting feedback control signals to a small fraction of nodes. We explore networks' controllability from not only mathematical analysis, but also the aspects of network topology and information diffusion. Then, the connection between pinning control and information diffusion is given, and pinning node selection is transferred into multi-spreader problem in information diffusion. Based on information diffusion, a heuristic method is proposed to select pinning nodes by optimizing the spreading ability of multiple spreaders. The proposed method greatly improves the controllability of large practical networks, and provides a new perspective to investigate pinning node selection.

  3. Guarded Cubical Type Theory

    DEFF Research Database (Denmark)

    Birkedal, Lars; Bizjak, Aleš; Clouston, Ranald;

    2016-01-01

    This paper improves the treatment of equality in guarded dependent type theory (GDTT), by combining it with cubical type theory (CTT). GDTT is an extensional type theory with guarded recursive types, which are useful for building models of program logics, and for programming and reasoning with co...

  4. Pinning Down versus Density

    OpenAIRE

    2015-01-01

    The pinning down number $ {pd}(X)$ of a topological space $X$ is the smallest cardinal $\\kappa$ such that for any neighborhood assignment $U:X\\to \\tau_X$ there is a set $A\\in [X]^\\kappa$ with $A\\cap U(x)\

  5. [Toxicity of puffer fish fins].

    Science.gov (United States)

    Honda, Shunichi; Ichimaru, Shunichi; Arakawa, Osamu; Takatani, Tomohiro; Noguchi, Tamao; Ishizaki, Shoichiro; Nagashima, Yuji

    2007-10-01

    Puffer fish is prized as a Japanese traditional food and its fin is also used in the cuisine. However, whether the fin is edible or not is determined for convenience from the toxicity of skin, since little information is available about the toxicity of puffer fish fins. In the present study, we examined the toxicity of fins and skin of three toxic species, Takifugu vermicularis, T. snyderi, and T. porphyreus. The toxicity of T. vermicularis fins (< 5-52.4 MU/g) was significantly lower than that of skin (<5-1200 MU/g). HPLC analysis showed that tetrodotoxin was a major toxic principle irrespective of the toxicity value in each tissue of T. vermicularis. In the case of T. snyderi and T. porphyreus, the toxicity of fins was at almost the same level as that of the skin. The toxicity (< 10-12 MU/g) of caudal fins of T. porphyreus was apparently increased to 16.5-22.0 MU/g by drying. However, the toxin amounts in the dried fins were slightly decreased as compared with those of the non-dried fins. These results demonstrate that puffer fish with toxic skin also have toxic fins.

  6. Fin de Copenhagen

    DEFF Research Database (Denmark)

    Baumeister, Ruth

    2016-01-01

    FIN DE COPENHAGUE this book by the Danish Cobra artist Asger Jorn and the French philosopher Guy Debord, is the first in a series of two and was published in 1957, shortly before the authors founded the Situationist International. According to Jorn, upon arrival to Copenhagen, they stole some new......´s and Jorn´s theories but in its representation of the environment as a range of geographic, social, political and economic dynamics but also proposes a vision of the future city as a multi-layered network in a state of constant transformation....

  7. Fin de temporada

    OpenAIRE

    2012-01-01

    Como una jauría de leonas enjauladas que recién son liberadas, corren cientos de mujeres a buscar aquellos coloridos y centelleantes carteles que anuncian efusivos la llegada del fin de la temporada. Las tiendas hacen todo tipo de descuentos a las mercancías un poco sucias, desgastadas, arrugadas y pasadas de  moda. No son despreciadas por aquellas mujeres a las que el recorte de la mesada no les da para comprar lo que está de moda. Por  los  amplios  pasillos  ahora ...

  8. Brush/Fin Thermal Interfaces

    Science.gov (United States)

    Knowles, Timothy R.; Seaman, Christopher L.; Ellman, Brett M.

    2004-01-01

    Brush/fin thermal interfaces are being developed to increase heat-transfer efficiency and thereby enhance the thermal management of orbital replaceable units (ORUs) of electronic and other equipment aboard the International Space Station. Brush/fin thermal interfaces could also be used to increase heat-transfer efficiency in terrestrial electronic and power systems. In a typical application according to conventional practice, a replaceable heat-generating unit includes a mounting surface with black-anodized metal fins that mesh with the matching fins of a heat sink or radiator on which the unit is mounted. The fins do not contact each other, but transfer heat via radiation exchange. A brush/fin interface also includes intermeshing fins, the difference being that the gaps between the fins are filled with brushes made of carbon or other fibers. The fibers span the gap between intermeshed fins, allowing heat transfer by conduction through the fibers. The fibers are attached to the metal surfaces as velvet-like coats in the manner of the carbon fiber brush heat exchangers described in the preceding article. The fiber brushes provide both mechanical compliance and thermal contact, thereby ensuring low contact thermal resistance. A certain amount of force is required to intermesh the fins due to sliding friction of the brush s fiber tips against the fins. This force increases linearly with penetration distance, reaching 1 psi (6.9 kPa) for full 2-in. (5.1 cm) penetration for the conventional radiant fin interface. Removal forces can be greater due to fiber buckling upon reversing the sliding direction. This buckling force can be greatly reduced by biasing the fibers at an angle perpendicularly to the sliding direction. Means of containing potentially harmful carbon fiber debris, which is electrically conductive, have been developed. Small prototype brush/fin thermal interfaces have been tested and found to exhibit temperature drops about onesixth of that of conventional

  9. Guarded Cubical Type Theory

    DEFF Research Database (Denmark)

    Birkedal, Lars; Bizjak, Aleš; Clouston, Ranald;

    2016-01-01

    This paper improves the treatment of equality in guarded dependent type theory (GDTT), by combining it with cubical type theory (CTT). GDTT is an extensional type theory with guarded recursive types, which are useful for building models of program logics, and for programming and reasoning...... with coinductive types. We wish to implement GDTT with decidable type-checking, while still supporting non-trivial equality proofs that reason about the extensions of guarded recursive constructions. CTT is a variation of Martin-L\\"of type theory in which the identity type is replaced by abstract paths between...... terms. CTT provides a computational interpretation of functional extensionality, is conjectured to have decidable type checking, and has an implemented type-checker. Our new type theory, called guarded cubical type theory, provides a computational interpretation of extensionality for guarded recursive...

  10. Guarded Cubical Type Theory

    DEFF Research Database (Denmark)

    Birkedal, Lars; Bizjak, Aleš; Clouston, Ranald;

    2016-01-01

    This paper improves the treatment of equality in guarded dependent type theory (GDTT), by combining it with cubical type theory (CTT). GDTT is an extensional type theory with guarded recursive types, which are useful for building models of program logics, and for programming and reasoning...... with coinductive types. We wish to implement GDTT with decidable type checking, while still supporting non-trivial equality proofs that reason about the extensions of guarded recursive constructions. CTT is a variation of Martin-L\\"of type theory in which the identity type is replaced by abstract paths between...... terms. CTT provides a computational interpretation of functional extensionality, enjoys canonicity for the natural numbers type, and is conjectured to support decidable type-checking. Our new type theory, guarded cubical type theory (GCTT), provides a computational interpretation of extensionality...

  11. Heat transfer enhancement by pin elements

    Energy Technology Data Exchange (ETDEWEB)

    Sahiti, N.; Durst, F.; Dewan, A. [LSTM-Erlangen, Institute of Fluid Mechanics, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Cauerstrasse 4, D-91058 Erlangen (Germany)

    2005-11-01

    Heat transfer enhancement is an active and important field of engineering research since increases in the effectiveness of heat exchangers through suitable heat transfer augmentation techniques can result in considerable technical advantages and savings of costs. Considerable enhancements were demonstrated in the present work by using small cylindrical pins on surfaces of heat exchangers. A partly quantitative theoretical treatment of the proposed method is presented. It uses simple relationships for the conductive and convective heat transfer to derive an equation that shows which parameters permit the achievement of heat transfer enhancements. Experiments are reported that demonstrate the effectiveness of the results of the proposed approach. It is shown that the suggested method of heat transfer enhancements is much more effective than existing methods, since it results in an increase in heat transfer area (like fins) and also an increase in the heat transfer coefficient. (author)

  12. SIMULATE-4 pin power calculations

    Energy Technology Data Exchange (ETDEWEB)

    Bahadir, T. [Studsvik Scandpower, Inc., 1087 Beacon St., Newton, MA 02459 (United States); Lindahl, S. Oe [Studsvik Scandpower AB, Hantverkargatan 2A, SE-722 12 Vasteraas (Sweden)

    2006-07-01

    A new pin power reconstruction module has been implemented in Studsvik Scandpower's next generation nodal code, SIMULATE-4. Heterogeneous pin powers are calculated by modulating multi-group pin powers from the sub-mesh solver of SIMULATE-4 with pin form factors from single-assembly CASMO-5 lattice calculations. The multi-group pin power model captures instantaneous spectral effects, and actinide tracking on the assembly sub-mesh describes exposure-induced pin power variations. Model details and verification tests against high order multi-assembly transport methods are presented. The accuracy of the new methods is also demonstrated by comparing SIMULATE-4 calculations with measured critical experiment pin powers. (authors)

  13. Fvm Analysis for Thermal and Hydraulic Behaviour of Circular Finned Mpfhs by Using Ag-H20 Nano

    Directory of Open Access Journals (Sweden)

    Fluid Kuber Dwivedi

    2014-07-01

    Full Text Available In this exploration the influence of using two types of Nano fluids (Ag-water and Al203-water as a coolant at volumetric concentration is taken (c= 4% in micro pin fin heat sink with circular fins in addition to the un-finned micro-channel heat sink is deliberated with the help of commercially available computational fluid dynamics software Fluent 14. The evaluation of flow and heat transfer characteristics of MPFHS and cooling fluids has been made under the similar boundary condition; at the range of Reynolds number used is (100-500. The gotten outcomes is exemplified that, Ag-water Nano fluid is gives the minimum pressure drop and slightly maximum heat transfer rate compared to Al203-water Nano fluid. And circular finned heat sink is dissipating more amount of heat compared to un-finned micro-channel heat sink. But it is also gives the maximum pressure drop due to finned area.

  14. Toward quantum FinFET

    CERN Document Server

    Wang, Zhiming

    2013-01-01

    This book reviews a range of quantum phenomena in novel nanoscale transistors called FinFETs, including quantized conductance of 1D transport, single electron effect, tunneling transport, etc. The goal is to create a fundamental bridge between quantum FinFET and nanotechnology to stimulate readers' interest in developing new types of semiconductor technology. Although the rapid development of micro-nano fabrication is driving the MOSFET downscaling trend that is evolving from planar channel to nonplanar FinFET, silicon-based CMOS technology is expected to face fundamental limits in the near future. Therefore, new types of nanoscale devices are being investigated aggressively to take advantage of the quantum effect in carrier transport. The quantum confinement effect of FinFET at room temperatures was reported following the breakthrough to sub-10nm scale technology in silicon nanowires. With chapters written by leading scientists throughout the world, Toward Quantum FinFET provides a comprehensive introductio...

  15. A STUDY ON THE FINS OF HEAT EXCHANGERS FROM OPTIMIZATION OF ENTROPY GENERATION%换热器肋片的最小熵产优化研究

    Institute of Scientific and Technical Information of China (English)

    苏亚欣; 骆仲泱; 岑可法

    1999-01-01

    The purpose of this paper is to find a new way of fin design to minimize the irreversibilities due to heat transfer and fluid friction and maximize the available work of the working fluid. The general entropy generation formulas for fins are derived at first according to the first and second law of thermodynamics, then a theoretical analysis on cylindrical pin fins and rectangular straight fins is made by using the above formulas. The minimum entropy generation formulas for these two types of fins are obtained and a principle for fin optimization is proposed, where the minimum entropy generation is chosen to be the objective function to be studied. The effect of different parameters on fin entropy generation is discussed in detail in forced convection heat transfer.

  16. Anisotropic cubic curvature couplings

    CERN Document Server

    Bailey, Quentin G

    2016-01-01

    To complement recent work on tests of spacetime symmetry in gravity, cubic curvature couplings are studied using an effective field theory description of spacetime-symmetry breaking. The associated mass dimension 8 coefficients for Lorentz violation studied do not result in any linearized gravity modifications and instead are revealed in the first nonlinear terms in an expansion of spacetime around a flat background. We consider effects on gravitational radiation through the energy loss of a binary system and we study two-body orbital perturbations using the post-Newtonian metric. Some effects depend on the internal structure of the source and test bodies, thereby breaking the Weak Equivalence Principle for self-gravitating bodies. These coefficients can be measured in solar-system tests, while binary-pulsar systems and short-range gravity tests are particularly sensitive.

  17. Pinning, de-pinning and re-pinning of a slowly varying rivulet

    KAUST Repository

    Paterson, C.

    2013-09-01

    The solutions for the unidirectional flow of a thin rivulet with prescribed volume flux down an inclined planar substrate are used to describe the locally unidirectional flow of a rivulet with constant width (i.e. pinned contact lines) but slowly varying contact angle as well as the possible pinning and subsequent de-pinning of a rivulet with constant contact angle and the possible de-pinning and subsequent re-pinning of a rivulet with constant width as they flow in the azimuthal direction from the top to the bottom of a large horizontal cylinder. Despite being the same locally, the global behaviour of a rivulet with constant width can be very different from that of a rivulet with constant contact angle. In particular, while a rivulet with constant non-zero contact angle can always run from the top to the bottom of the cylinder, the behaviour of a rivulet with constant width depends on the value of the width. Specifically, while a narrow rivulet can run all the way from the top to the bottom of the cylinder, a wide rivulet can run from the top of the cylinder only to a critical azimuthal angle. The scenario in which the hitherto pinned contact lines of the rivulet de-pin at the critical azimuthal angle and the rivulet runs from the critical azimuthal angle to the bottom of the cylinder with zero contact angle but slowly varying width is discussed. The pinning and de-pinning of a rivulet with constant contact angle, and the corresponding situation involving the de-pinning and re-pinning of a rivulet with constant width at a non-zero contact angle which generalises the de-pinning at zero contact angle discussed earlier, are described. In the latter situation, the mass of fluid on the cylinder is found to be a monotonically increasing function of the constant width. © 2013 Elsevier Masson SAS. All rights reserved.

  18. Fvm Analysis for Thermal and Hydraulic Behaviour of Circular Finned Mpfhs by Using Ag-H20 Nano

    OpenAIRE

    Fluid Kuber Dwivedi; Rupesh Kumar Malviya

    2014-01-01

    In this exploration the influence of using two types of Nano fluids (Ag-water and Al203-water) as a coolant at volumetric concentration is taken (c= 4%) in micro pin fin heat sink with circular fins in addition to the un-finned micro-channel heat sink is deliberated with the help of commercially available computational fluid dynamics software Fluent 14. The evaluation of flow and heat transfer characteristics of MPFHS and cooling fluids has been made under the similar boundary condition; at t...

  19. Fuel pin cladding

    Science.gov (United States)

    Vaidyanathan, S.; Adamson, M.G.

    1986-01-28

    Disclosed is an improved fuel pin cladding, particularly adapted for use in breeder reactors, consisting of composite tubing with austenitic steel on the outer portion of the thickness of the tube wall and with nickel and/or ferritic material on the inner portion of the thickness of the tube wall. The nickel forms a sacrificial barrier as it reacts with certain fission products thereby reducing fission product activity at the austenitic steel interface. The ferritic material forms a preventive barrier for the austenitic steel as it is immune to liquid metal embrittlement. The improved cladding permits the use of high density fuel which in turn leads to a better breeding ratio in breeder reactors, and will increase the threshold at which failure occurs during temperature transients. 2 figs.

  20. Fuel pin cladding

    Science.gov (United States)

    Vaidyanathan, Swaminathan; Adamson, Martyn G.

    1986-01-01

    An improved fuel pin cladding, particularly adapted for use in breeder reactors, consisting of composite tubing with austenitic steel on the outer portion of the thickness of the tube wall and with nickel and/or ferritic material on the inner portion of the thickness of the tube wall. The nickel forms a sacrificial barrier as it reacts with certain fission products thereby reducing fission product activity at the austenitic steel interface. The ferritic material forms a preventive barrier for the austenitic steel as it is immune to liquid metal embrittlement. The improved cladding permits the use of high density fuel which in turn leads to a better breeding ratio in breeder reactors, and will increase the threshold at which failure occurs during temperature transients.

  1. 50 CFR 600.1204 - Shark finning; possession at sea and landing of shark fins.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Shark finning; possession at sea and landing of shark fins. 600.1204 Section 600.1204 Wildlife and Fisheries FISHERY CONSERVATION AND... PROVISIONS Shark Finning § 600.1204 Shark finning; possession at sea and landing of shark fins. (a)(1)...

  2. Paddle-pin alinement test

    Science.gov (United States)

    Gilliam, D. M.; Foster, J. A.

    1977-01-01

    Segmented insulated test bar speeds up patch distributor paddle-pin test. Device eliminates need to disconnect cables or remove distributor. Printed circuit cable and connector reduces weight on bar, adding to tester portability.

  3. Pinning Mechanisms in YBCO Tapes

    CERN Document Server

    Spera, Marcello; Ballarino, Amalia

    2015-01-01

    In this thesis work, a study on flux pinning mechanisms of commercial YBCO tapes is presented. This study has been performed via critical current characterization using transport (via direct I-V curves) and magnetization (via a Vibrating Sample Magnetometer) measurements. The latter ones turned out to be better concerning the comprehension of the pinning landscape of the provided samples, as a wider range of magnetic fields and temperatures is available for those measurements in the setup I used. The comparison of the experimental data with existing theoretical models allowed me to draw a picture of the pinning mechanisms underlying in each sample, and they turned out to be quite different one another. Moreover, for high-performance research tapes, another interesting feature has been found: the counterplay between the self-field critical current and the in-field one. Very well engineered artificial pinning structures limit the self-field critical current density due to the hi...

  4. A Cubic Tree Taper Model

    National Research Council Canada - National Science Library

    Goodwin, Adrian N

    2009-01-01

    A flexible tree taper model based on a cubic polynomial is described. It is algebraically invertible and integrable, and can be constrained by one or two diameters, neither of which need be diameter at breast height (DBH...

  5. PHASE CHANGE AROUND A FINNED TUBE

    Directory of Open Access Journals (Sweden)

    Aytunç EREK

    2003-01-01

    Full Text Available This study presents the heat transfer enhancement in the thermal energy storage system by using radially finned tube. The solution of the system consists of the solving the equations of the heat transfer fluid (HTF, the pipe wall and fin, and the phase change material (PCM as one domain. The control volume finite difference approach and the semi implicit solver (SIS are used to solve the equations. Fully developed velocity distribution is taken in the HTF. Flow parameters (Re number and inlet temperature of coolant and fin parameters (the number of fins, fin length, fin thickness are found to influence solidification fronts and the total stored energy.

  6. Source/drain eSiGe engineering for FinFET technology

    Science.gov (United States)

    Peng, Jianwei; Qi, Yi; Lo, Hsien-Ching; Zhao, Pei; Yong, Chloe; Yan, Jianghu; Dou, Xinyuan; Zhan, Hui; Shen, Yanping; Regonda, Suresh; Hu, Owen; Yu, Hong; Joshi, Manoj; Adams, Charlotte; Carter, Rick; Samavedam, Srikanth

    2017-09-01

    Epitaxy growth loading effect—the growth rate difference between device macros due to their local open ratio difference—is an important consideration for device design and thus process optimization. A poor loading process leads to device performance delta across macros. For eSiGe on FinFETs, we found that optimized eSiGe on FinFETs saturates as the eSiGe diamond pins at fin top surface and the fin-sidewall-spacer (FSS). The eSiGe diamond size measured by lateral CD does not increase with deposition time, but it linearly correlates to cavity depth and FSS pushdown. In principle, the eSiGe loading effect can be addressed with an extended growth time until every device macros saturates. However, it is found that, the epitaxy growth related defects, measured by abnormal eSiGe and unwanted growth, can also be elevated to an unacceptable level for a longer deposition time. Thus, the eSiGe loading process still needs to be optimized for an improved process window. In this work, an optimized eSiGe process achieves reduced loading between 2-fin and 40-fin macros and thus a smaller pFET performance gap between the two device macros.

  7. Fin-tube solar collectors

    Science.gov (United States)

    1980-01-01

    Report presents test procedures and results of thermal-performance evaluation of seven commercial fin tube (liquid) solar collector-absorber plates. Tests were conducted indoors at Marshall Space Flight Center Solar simulator. Results are graphically shown along with supporting test data and summary, indicating efficiency as function of collector inlet temperature.

  8. Enhanced pinning in superconducting thin films with graded pinning landscapes

    Science.gov (United States)

    Motta, M.; Colauto, F.; Ortiz, W. A.; Fritzsche, J.; Cuppens, J.; Gillijns, W.; Moshchalkov, V. V.; Johansen, T. H.; Sanchez, A.; Silhanek, A. V.

    2013-05-01

    A graded distribution of antidots in superconducting a-Mo79Ge21 thin films has been investigated by magnetization and magneto-optical imaging measurements. The pinning landscape has maximum density at the sample border, decreasing linearly towards the center. Its overall performance is noticeably superior than that for a sample with uniformly distributed antidots: For high temperatures and low fields, the critical current is enhanced, whereas the region of thermomagnetic instabilities in the field-temperature diagram is significantly suppressed. These findings confirm the relevance of graded landscapes on the enhancement of pinning efficiency, as recently predicted by Misko and Nori [Phys. Rev. B 85, 184506 (2012)].

  9. Interface roughening and pinning

    Science.gov (United States)

    Roux, Stéphane; Hansen, Alex

    1994-04-01

    We study a simple model for thé pinning of an interface by impurities with random strengths, and thé depinning due to thé applied pressure, in a quasi-static propagation lirait. The model is very close to thé so called "Robin Hood" model introduced by Zaitsev. It is designed to describe e.g. thé invasion of a wetting fluid (imbibition) in a heterogeneous porous medium containing a second immiscible fluid. The relation between this model and other previously proposed approaches is discussed. The front of thé invaded domain is shown to develop a self-affine structure with an increase of thé roughness as a power-law of thé injected volume. The value of thé apparent roughness exponent can be favorably compared to some experimental measurements although we argue that thé true roughness exponent is out of reach of commonly used methods. We show that thé distribution f(d, Δ t) of distances d between discrete local invasions at a time interval Δ t can be described by a scaling law f(d, Δ t) = d^{-1}\\varphi(d/sqrt{Δ t}). This form can be obtained from thé identification of a hierarchical structure of "bursts" in thé pressure signal. Those "bursts" are quahtatively similar to those observed in quasistatic drainage, (i.e. invasion percolation), although characterized by différent scaling indices. Nous étudions un modèle simple pour analyser l'accrochage d'une interface sur des impuretés et le décrochage sous l'effet d'une pression appliquée, dans une limite quasi-statique. Ce modèle est très voisin du modèle "Robin Hood" introduit par Zaitsev. Il s'applique en particulier à l'invasion d'un fluide mouillant (imbibition) dans un milieu poreux hétérogène contenant un fluide immiscible. Nous discutons les relations entre ce modèle et d'autres approches proposées pour décrire ce phénomène. Le front d'invasion acquiert une structure auto-affine, avec un développement de la rugosité selon une loi de puissance du volume injecté. La valeur de l

  10. PinBus Interface Design

    Energy Technology Data Exchange (ETDEWEB)

    Hammerstrom, Donald J.; Adgerson, Jewel D.; Sastry, Chellury; Pratt, Richard M.; Pratt, Robert G.

    2009-12-30

    On behalf of the U.S. Department of Energy, PNNL has explored and expanded upon a simple control interface that might have merit for the inexpensive communication of smart grid operational objectives (demand response, for example) to small electric end-use devices and appliances. The approach relies on bi-directional communication via the electrical voltage states of from one to eight shared interconnection pins. The name PinBus has been suggested and adopted for the proposed interface protocol. The protocol is defined through the presentation of state diagrams and the pins’ functional definitions. Both simulations and laboratory demonstrations are being conducted to demonstrate the elegance and power of the suggested approach. PinBus supports a very high degree of interoperability across its interfaces, allowing innumerable pairings of devices and communication protocols and supporting the practice of practically any smart grid use case.

  11. Universal Reconfiguration of (Hyper-)cubic Robots

    OpenAIRE

    Abel, Zachary; Kominers, Scott D.

    2008-01-01

    We study a simple reconfigurable robot model which has not been previously examined: cubic robots comprised of three-dimensional cubic modules which can slide across each other and rotate about each others' edges. We demonstrate that the cubic robot model is universal, i.e., that an n-module cubic robot can reconfigure itself into any specified n-module configuration. Additionally, we provide an algorithm that efficiently plans and executes cubic robot motion. Our results directly extend to a...

  12. Synchronizability on complex networks via pinning control

    Indian Academy of Sciences (India)

    Yi Liang; Xingyuan Wang

    2013-04-01

    It is proved that the maximum eigenvalue sequence of the principal submatrices of coupling matrix is decreasing. The method of calculating the number of pinning nodes is given based on this theory. The findings reveal the relationship between the decreasing speed of maximum eigenvalue sequence of the principal submatrices for coupling matrix and the synchronizability on complex networks via pinning control. We discuss the synchronizability on some networks, such as scale-free networks and small-world networks. Numerical simulations show that different pinning strategies have different pinning synchronizability on the same complex network, and the synchronizability with pinning control is consistent with one without pinning control in various complex networks.

  13. The optimum fin spacing of circular tube bank fin heat exchanger with vortex generators

    Science.gov (United States)

    Hu, Wanling; Su, Mei; Wang, Liangcheng; Zhang, Qiang; Chang, Limin; Liu, Song; Wang, Liangbi

    2013-09-01

    In real application, once the pattern of fin is determined, fin spacing of tube bank fin heat exchanger can be adjusted in a small region, and air flow velocity in the front of the heat exchanger is not all the same. Therefore, the effects of fin spacing on heat transfer performance of such heat exchanger are needed. This paper numerically studied the optimal fin spacing regarding the different front flow velocities of a circular tube bank fin heat exchanger with vortex generators. To screen the optimal fin spacing, an appropriate evaluation criterion JF was used. The results show that when front velocity is 1.75 m/s, the optimal fin spacing is 2.25 mm, when front velocity is 2.5 m/s, the optimal fin spacing is 2 mm, and when front velocity is higher than 2.5 m/s, the optimal fin spacing is 1.75 mm.

  14. A COMPARISON OF HEAT TRANSFER AROUND A SINGLE SERRATED FINNED TUBE AND A PLAIN FINNED TUBE

    Directory of Open Access Journals (Sweden)

    S.R.Mcilwain

    2010-02-01

    Full Text Available With comparable bundle geometry, serrated fin finned tube heat exchangers transfer more heat than plain finned ones. There are believed to be many factors in this behaviour, and this investigation used CFD to examine the heat transfer and fluid flow patterns around the fins to try to understand the magnitude of the differences in the processes. The study is a first step in developing a new theory-based method to predict the performance of serrated fin tube bundles.

  15. A COMPARISON OF HEAT TRANSFER AROUND A SINGLE SERRATED FINNED TUBE AND A PLAIN FINNED TUBE

    OpenAIRE

    2010-01-01

    With comparable bundle geometry, serrated fin finned tube heat exchangers transfer more heat than plain finned ones. There are believed to be many factors in this behaviour, and this investigation used CFD to examine the heat transfer and fluid flow patterns around the fins to try to understand the magnitude of the differences in the processes. The study is a first step in developing a new theory-based method to predict the performance of serrated fin tube bundles.

  16. Improved pinning regime by energetic ions using reduction of pinning potential

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Roy; Gandini, Alberto; Sawh, Ravi-Persad; Parks, Drew; Mayes, Bill

    2003-05-15

    When ion damage is used to create pinning centers, full columnar pinning centers provide the largest pinning potential, U{sub pin}, but not the greatest J{sub c} or pinned field, B{sub pin}. Some of the characteristics of columnar defects which limit J{sub c} and B{sub pin} are discussed, including reduction of percolation path, and the need for a larger number of columns of damage, for pinning, than are usually estimated. It is concluded that columnar pinning centers are limited to B{sub pin}<4 T, and also severely reduce J{sub c}. Evidence is reviewed that aligned damage, or broken-columnar pinning centers, described herein, can provide orders of magnitude higher J{sub c}, and higher pinned field, despite providing lower U{sub pin}. A pinning center morphology is discussed which utilizes multiple-in-line-damage (MILD). For, e.g., present day large grain HTS J{sub c}, obtainable by MILD pinning, is estimated to be of the order of 10{sup 6} A/cm{sup 2} at 77 K, even when crystal plane alignment and weak links are not improved. Pinned field is increased by over an order of magnitude. An experiment is proposed to confirm these observations, and to directly compare MILD to columnar pinning centers. It will also determine the optimum MILD structure. Other measurements of interest, made possible by the same data set, are described.

  17. Effects of Fin Shape on Condensation Heat Transfer and Pressure Drop inside Herringbone Micro Fin Tubes

    Science.gov (United States)

    Miyara, Akio; Otsubo, Yusuke; Ohtsuka, Satoshi

    Experiments of in-tube condensation of R410A have been carried out for as mooth tube, a h elical micro fin tube and five types of herringbone micro fin tubes. In the herringbone micro fin tube, the micro fins work to remove liquid at fin-diverging parts and collect liquid at fin-converging parts. In the high mass velocity region, heat transfer coefficient of all the herringbone tubes is about 2-4 times higher than that of the helical micro fin tube. In the low mass velocity region, however, the heat transfer coefficients of the herringbone micro fin tubes are equal to or smaller than those of the helical micro fin tube. Up to the fin height of 0.18 mm, the heat transfer coefficient is higher for higher fin, whereas that of ah igher fin tube is saturated. The pressure drop increases with increasing fin height. The helix angle strongly affects the heat transfer and pressure drop. Higher helix angle causes higher heat transfer coefficient and higher pressure drop. In the case of the herringbone tube which has shorter fin and/or smaller helix angle, pressure drops are equal to or lower than that of the helical micro fin tube, whereas those of other tubes are higher.

  18. Cubication of Conservative Nonlinear Oscillators

    Science.gov (United States)

    Belendez, Augusto; Alvarez, Mariela L.; Fernandez, Elena; Pascual, Immaculada

    2009-01-01

    A cubication procedure of the nonlinear differential equation for conservative nonlinear oscillators is analysed and discussed. This scheme is based on the Chebyshev series expansion of the restoring force, and this allows us to approximate the original nonlinear differential equation by a Duffing equation in which the coefficients for the linear…

  19. Cryptographic Analysis in Cubic Time

    DEFF Research Database (Denmark)

    Nielson, Flemming; Nielson, Hanne Riis; Seidl, H.

    2004-01-01

    The spi-calculus is a variant of the polyadic pi-calculus that admits symmetric cryptography and that admits expressing communication protocols in a precise though still abstract way. This paper shows that context-independent control flow analysis can be calculated in cubic time despite the fact ...

  20. The diagonalization of cubic matrices

    Science.gov (United States)

    Cocolicchio, D.; Viggiano, M.

    2000-08-01

    This paper is devoted to analysing the problem of the diagonalization of cubic matrices. We extend the familiar algebraic approach which is based on the Cardano formulae. We rewrite the complex roots of the associated resolvent secular equation in terms of transcendental functions and we derive the diagonalizing matrix.

  1. Multi-stable dissipative structures pinned to dual hot spots

    CERN Document Server

    Tsang, Cheng Hou; Chow, Kwok Wing

    2011-01-01

    We analyze the formation of one-dimensional localized patterns in a nonlinear dissipative medium including a set of two narrow "hot spots" (HSs), which carry the linear gain, local potential, cubic self-interaction, and cubic loss, while the linear loss acts in the host medium. This system can be realized, as a spatial-domain one, in optics, and also in Bose-Einstein condensates of quasi-particles in solid-state settings. Recently, exact solutions were found for localized modes pinned to the single HS represented by the delta-function. The present paper reports analytical and numerical solutions for coexisting two- and multi-peak modes, which may be symmetric or antisymmetric with respect to the underlying HS pair. Stability of the modes is explored through simulations of their perturbed evolution. The sign of the cubic nonlinearity plays a crucial role: in the case of the self-focusing, only the fundamental symmetric and antisymmetric modes, with two local peaks tacked to the HSs, and no additional peaks bet...

  2. Numerical Analysis of Aerodynamic Characteristics of the Finned Surfaces with Cross-inclined Fins

    Directory of Open Access Journals (Sweden)

    Lagutin A. E.

    2016-12-01

    Full Text Available This paper presents results of numerical research and analyses air-side hydraulic performance of tube bundles with cross inclined fins. The numerical simulation of the fin-tube heat exchanger was performed using the Comsol Femlab software. The results of modeling show the influence of fin inclination angle and tube pitch on hydraulic characteristics of finned surfaces. A series of numerical tests were carried out for tube bundles with different inclination angles (γ =900, 850, 650, 60, the fin pitch u=4 mm. The results indicate that tube bundles with cross inclined fins can significantly enhance the average integral value of the air flow rate in channel between fins in comparison with conventional straight fins. Aerodynamic processes on both sides of modificated channel between inclined fins were analyzed. The verification procedures for received results of numerical modeling with experimental data were performed.

  3. Pinning-controllability of complex networks

    OpenAIRE

    Sorrentino, Francesco; Di Bernardo, Mario; Garofalo, Franco; Chen, Guanrong

    2007-01-01

    We study the problem of controlling a general complex network towards an assigned synchronous evolution, by means of a pinning control strategy. We define the pinning-controllability of the network in terms of the spectral properties of an extended network topology. The roles of the control and coupling gains as well as of the number of pinned nodes are also discussed.

  4. A biorobotic model of the sunfish pectoral fin for investigations of fin sensorimotor control

    Energy Technology Data Exchange (ETDEWEB)

    Phelan, Chris; Tangorra, James [Department of Mechanical Engineering, Drexel University, Philadelphia, PA 19104 (United States); Lauder, George [Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138 (United States); Hale, Melina, E-mail: tangorra@coe.drexel.ed [Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637 (United States)

    2010-09-15

    A comprehensive understanding of the control of flexible fins is fundamental to engineering underwater vehicles that perform like fish, since it is the fins that produce forces which control the fish's motion. However, little is known about the fin's sensory system or about how fish use sensory information to modulate the fin and to control propulsive forces. As part of a research program that involves neuromechanical and behavioral studies of the sunfish pectoral fin, a biorobotic model of the pectoral fin and of the fin's sensorimotor system was developed and used to investigate relationships between sensory information, fin ray motions and propulsive forces. This robotic fin is able to generate the motions and forces of the biological fin during steady swimming and turn maneuvers, and is instrumented with a relatively small set of sensors that represent the biological lateral line and receptors hypothesized to exist intrinsic to the pectoral fin. Results support the idea that fin ray curvature, and the pressure in the flow along the wall that represents the fish body, capture time-varying characteristics of the magnitude and direction of the force created throughout a fin beat. However, none of the sensor modalities alone are sufficient to predict the propulsive force. Knowledge of the time-varying force vector with sufficient detail for the closed-loop control of fin ray motion will result from the integration of characteristics of many sensor modalities.

  5. Self-shearing retentive pins: a laboratory evaluation of pin channel penetration before shearing.

    Science.gov (United States)

    Barkmeier, W W; Cooley, R L

    1979-09-01

    This laboratory study determined the depth reached by self-shearing pins in dentin pin channels. Pin channels were prepared with the self-limiting shoulder twist drill for each of the four systems tested. Mean channel depth reached for the various pin systems was: Stabilok (small), 2.31 mm; Stabilok (medium), 1.78 mm; Reten Pin, 1.40 mm; and TMS (Regular), 2.04 mm. A coparison was also made by calculating the mean percent of penetration in relation to the depth of prepared pin channel: Stabilok (small), 92.50%; Stabilok (medium), 63.62%; Reten Pin, 66.67%; and TMS (Regular) 81.75%.

  6. Visiones de fin de siglo

    OpenAIRE

    Acchini, Leonardo Martínez; Alejo, Esteban Ticona; Angulo, Salvador; Berthin, Elizabeth Cécile; Bravo, Carmen Giona; Bravo, María Celia; Burke, Melvin; C., Javier Sanjinés; Campi,Daniel; Canqui, Roberto Choque; Capra, Ana María Seoane de; Contreras, Manuel E.; Coro, Víctor Hugo Quintanilla; Correa, Loreto; Guerrero, Alicia Castellanos

    2016-01-01

    La presente publicación concentra los trabajos presentados por investigadores nacionales y extranjeros en el "Il Encuentro Internacional de Historia. El siglo XX en Bolivia y América Latina. Visiones de fin de siglo", que se realizó en la ciudad de Cochabamba entre el 27 y el 31 de julio de 1998. El encuentro fue organizado por la "Coordinadora de Historia. Investigadores Asociados" y contó con el auspicio del Centro Cultural Portales con sede en esa ciudad, así como con el apoyo de las sigui...

  7. Cubication of conservative nonlinear oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Belendez, Augusto; Alvarez, Mariela L [Departamento de Fisica, Ingenieria de Sistemas y Teoria de la Senal, Universidad de Alicante, Apartado 99, E-03080 Alicante (Spain); Fernandez, Elena; Pascual, Inmaculada [Departamento de Optica, FarmacologIa y Anatomia, Universidad de Alicante, Apartado 99, E-03080 Alicante (Spain)], E-mail: a.belendez@ua.es

    2009-09-15

    A cubication procedure of the nonlinear differential equation for conservative nonlinear oscillators is analysed and discussed. This scheme is based on the Chebyshev series expansion of the restoring force, and this allows us to approximate the original nonlinear differential equation by a Duffing equation in which the coefficients for the linear and cubic terms depend on the initial amplitude, A, while in a Taylor expansion of the restoring force these coefficients are independent of A. The replacement of the original nonlinear equation by an approximate Duffing equation allows us to obtain an approximate frequency-amplitude relation as a function of the complete elliptic integral of the first kind. Some conservative nonlinear oscillators are analysed to illustrate the usefulness and effectiveness of this scheme.

  8. Cubic Matrix, Nambu Mechanics and Beyond

    OpenAIRE

    Kawamura, Y

    2002-01-01

    We propose a generalization of cubic matrix mechanics by introducing a canonical triplet and study its relation to Nambu mechanics. The generalized cubic matrix mechanics we consider can be interpreted as a “quantum” generalization of Nambu mechanics.

  9. Cubical sets and the topological topos

    DEFF Research Database (Denmark)

    Spitters, Bas

    2016-01-01

    Coquand's cubical set model for homotopy type theory provides the basis for a computational interpretation of the univalence axiom and some higher inductive types, as implemented in the cubical proof assistant. This paper contributes to the understanding of this model. We make three contributions...... show that it can also be a target for cubical realization by showing that Coquand's cubical sets classify the geometric theory of flat distributive lattices. As a side result, we obtain a simplicial realization of a cubical set. 2. Using the internal `interval' in the topos of cubical sets, we...... construct a Moore path model of identity types. 3. We construct a premodel structure internally in the cubical type theory and hence on the fibrant objects in cubical sets....

  10. Numbers for reducible cubic scrolls

    Directory of Open Access Journals (Sweden)

    Israel Vainsencher

    2004-12-01

    Full Text Available We show how to compute the number of reducible cubic scrolls of codimension 2 in (math blackboard symbol Pn incident to the appropriate number of linear spaces.Mostramos como calcular o número de rolos cúbicos redutíveis de codimensão 2 em (math blackboard symbol Pn incidentes a espaços lineares apropriados.

  11. Pinning control of chimera states

    Science.gov (United States)

    Gambuzza, Lucia Valentina; Frasca, Mattia

    2016-08-01

    The position of the coherent and incoherent domain of a chimera state in a ring of nonlocally coupled oscillators is strongly influenced by the initial conditions, making nontrivial the problem of confining them in a specific region of the structure. In this paper we propose the use of spatial pinning to induce a chimera state where the nodes belonging to one domain, either the coherent or the incoherent, are fixed by the control action. We design two different techniques according to the dynamics to be forced in the region of pinned nodes, and validate them on FitzHugh-Nagumo and Kuramoto oscillators. Furthermore, we introduce a suitable strategy to deal with the effects of finite size in small structures.

  12. Optimum design of cast iron finned radiator

    Institute of Scientific and Technical Information of China (English)

    赵立华; 张泓森; 董重成

    2003-01-01

    The height, thickness and spacing of fins have an impact on the thermal characteristics of a radiator.The calculation of heat output and metal thermal intensity for cast iron finned radiator are given by using heat transfer formula of vertical plate and parallel fins. Each factor having effect on the metal thermal intensity of a radiator is analyzed and the optimum structure parameters of a radiator are given in order to maximize metal thermal intensity.

  13. Cubic colloids : Synthesis, functionalization and applications

    NARCIS (Netherlands)

    Castillo, S.I.R.

    2015-01-01

    This thesis is a study on cubic colloids: micron-sized cubic particles with rounded corners (cubic superballs). Owing to their shape, particle packing for cubes is more efficient than for spheres and results in fascinating phase and packing behavior. For our cubes, the particle volume fraction when

  14. Cubic colloids : Synthesis, functionalization and applications

    NARCIS (Netherlands)

    Castillo, S.I.R.

    2015-01-01

    This thesis is a study on cubic colloids: micron-sized cubic particles with rounded corners (cubic superballs). Owing to their shape, particle packing for cubes is more efficient than for spheres and results in fascinating phase and packing behavior. For our cubes, the particle volume fraction when

  15. Solving Cubic Equations by Polynomial Decomposition

    Science.gov (United States)

    Kulkarni, Raghavendra G.

    2011-01-01

    Several mathematicians struggled to solve cubic equations, and in 1515 Scipione del Ferro reportedly solved the cubic while participating in a local mathematical contest, but did not bother to publish his method. Then it was Cardano (1539) who first published the solution to the general cubic equation in his book "The Great Art, or, The Rules of…

  16. Cubic Icosahedra? A Problem in Assigning Symmetry

    Science.gov (United States)

    Lloyd, D. R.

    2010-01-01

    There is a standard convention that the icosahedral groups are classified separately from the cubic groups, but these two symmetry types have been conflated as "cubic" in some chemistry textbooks. In this note, the connection between cubic and icosahedral symmetries is examined, using a simple pictorial model. It is shown that octahedral and…

  17. Be on Pins and Needles

    Institute of Scientific and Technical Information of China (English)

    周立

    2003-01-01

    英语对话:A:It seems you’re on pins and needles today.Anything troubling you?B:Yeah.I don’t know why bad things keep happening to me .You see,mycar was stolen and the warehouse had been broken into.I can’t keep myfinger on the causes of this damned thing.A:There must be someone who had planned that.Do you have a partieularperson in mind?

  18. VORTEX INDUCED VIBRATIONS OF FINNED CYLINDERS

    Institute of Scientific and Technical Information of China (English)

    SHA Yong; WANG Yong-xue

    2008-01-01

    This article presents the results of a numerical simulation on the vortex induced vibration of various finned cylinders at low Reynolds number. The non-dimensional, incompressible Navier-Stokes equations and continuity equation were adopted to simulate the fluid around the cylinder. The cylinder (with or without fins) in fluid flow was approximated as a mass-spring system. The fluid-body interaction of the cylinder with fins and uniform flow was numerically simulated by applying the displacement and stress iterative computation on the fluid-body interfaces. Both vortex structures and response amplitudes of cylinders with various arrangements of fins were analyzed and discussed. The remarkable decrease of response amplitude for the additions of Triangle60 fins and Quadrangle45 fins was found to be comparable with that of bare cylinder. However, the additions of Triangle00 fins and Quadrangle00 fins enhance the response amplitude greatly. Despite the assumption of two-dimensional laminar flow, the present study can give a good insight into the phenomena of cylinders with various arrangements of fins.

  19. Performance study of a fin and tube heat exchanger with different fin geometry

    OpenAIRE

    2016-01-01

    This study analyses the effect of different fin geometries on the heat transfer and pressure loss characteristics of a fin and tube heat exchanger. A numerical investigation is carried out on liquid–gas type double-finned tube heat exchanger under cross-flow condition. Three different cross-sections namely: a) Rectangular, b) Trapezoidal, c) Triangular are adopted to define the fin geometry. The CFD simulations are performed to incorporate coupled steady state conjugate heat transfer with the...

  20. Investigation of the bulk pinning force in YBCO superconducting films with nano-engineered pinning centres

    Science.gov (United States)

    Crisan, A.; Dang, V. S.; Yearwood, G.; Mikheenko, P.; Huhtinen, H.; Paturi, P.

    2014-08-01

    For practical applications of superconducting materials in applied magnetic fields, artificial pinning centres in addition to natural ones are required to oppose the Lorentz force. These pinning centres are actually various types of defects in the superconductor matrix. The pinning centres can be categorised on their dimension (volume, surface, or point) and on their character (normal cores or Δκ cores). We have used the Dew Hughes approach to determine the types of pinning centres present in various samples, with various thicknesses, temperatures and nanostructured additions to the superconducting matrix. Results show that normal surface pinning centres are present throughout almost all the samples, as dominant pinning mechanism. Such 2D extended pinning centres are mainly due to dislocations, grain boundaries, nanorods. Strong normal point pinning centres were found to be common in BZO doped YBCO samples. Other types of pinning centres, in various (minor) concentrations were also found in some of the samples.

  1. Cubic metaplectic forms and theta functions

    CERN Document Server

    Proskurin, Nikolai

    1998-01-01

    The book is an introduction to the theory of cubic metaplectic forms on the 3-dimensional hyperbolic space and the author's research on cubic metaplectic forms on special linear and symplectic groups of rank 2. The topics include: Kubota and Bass-Milnor-Serre homomorphisms, cubic metaplectic Eisenstein series, cubic theta functions, Whittaker functions. A special method is developed and applied to find Fourier coefficients of the Eisenstein series and cubic theta functions. The book is intended for readers, with beginning graduate-level background, interested in further research in the theory of metaplectic forms and in possible applications.

  2. Alignment Pins for Assembling and Disassembling Structures

    Science.gov (United States)

    Campbell, Oliver C.

    2008-01-01

    Simple, easy-to-use, highly effective tooling has been devised for maintaining alignment of bolt holes in mating structures during assembly and disassembly of the structures. The tooling was originally used during removal of a body flap from the space shuttle Atlantis, in which misalignments during removal of the last few bolts could cause the bolts to bind in their holes. By suitably modifying the dimensions of the tooling components, the basic design of the tooling can readily be adapted to other structures that must be maintained in alignment. The tooling includes tapered, internally threaded alignment pins designed to fit in the bolt holes in one of the mating structures, plus a draw bolt and a cup that are used to install or remove each alignment pin. In preparation for disassembly of two mating structures, external supports are provided to prevent unintended movement of the structures. During disassembly of the structures, as each bolt that joins the structures is removed, an alignment pin is installed in its place. Once all the bolts have been removed and replaced with pins, the pins maintain alignment as the structures are gently pushed or pulled apart on the supports. In assembling the two structures, one reverses the procedure described above: pins are installed in the bolt holes, the structures are pulled or pushed together on the supports, then the pins are removed and replaced with bolts. The figure depicts the tooling and its use. To install an alignment pin in a bolt hole in a structural panel, the tapered end of the pin is inserted from one side of the panel, the cup is placed over the pin on the opposite side of the panel, the draw bolt is inserted through the cup and threaded into the pin, the draw bolt is tightened to pull the pin until the pin is seated firmly in the hole, then the draw bolt and cup are removed, leaving the pin in place. To remove an alignment pin, the cup is placed over the pin on the first-mentioned side of the panel, the draw

  3. Niobium-titanium superconductors produced by powder metallurgy having artificial flux pinning centers

    Science.gov (United States)

    Jablonski, Paul D.; Larbalestier, David C.

    1993-01-01

    Superconductors formed by powder metallurgy have a matrix of niobium-titanium alloy with discrete pinning centers distributed therein which are formed of a compatible metal. The artificial pinning centers in the Nb-Ti matrix are reduced in size by processing steps to sizes on the order of the coherence length, typically in the range of 1 to 10 nm. To produce the superconductor, powders of body centered cubic Nb-Ti alloy and the second phase flux pinning material, such as Nb, are mixed in the desired percentages. The mixture is then isostatically pressed, sintered at a selected temperature and selected time to produce a cohesive structure having desired characteristics without undue chemical reaction, the sintered billet is reduced in size by deformation, such as by swaging, the swaged sample receives heat treatment and recrystallization and additional swaging, if necessary, and is then sheathed in a normal conducting sheath, and the sheathed material is drawn into a wire. The resulting superconducting wire has second phase flux pinning centers distributed therein which provide enhanced J.sub.ct due to the flux pinning effects.

  4. Weighted cubic and biharmonic splines

    Science.gov (United States)

    Kvasov, Boris; Kim, Tae-Wan

    2017-01-01

    In this paper we discuss the design of algorithms for interpolating discrete data by using weighted cubic and biharmonic splines in such a way that the monotonicity and convexity of the data are preserved. We formulate the problem as a differential multipoint boundary value problem and consider its finite-difference approximation. Two algorithms for automatic selection of shape control parameters (weights) are presented. For weighted biharmonic splines the resulting system of linear equations can be efficiently solved by combining Gaussian elimination with successive over-relaxation method or finite-difference schemes in fractional steps. We consider basic computational aspects and illustrate main features of this original approach.

  5. Plastic Guidance Fins for Long Rod Projectiles .

    Directory of Open Access Journals (Sweden)

    Mark L. Bundy

    1997-10-01

    Full Text Available Projectile tail fins on long rod kinetic energy (KE penetrators serve the same purpose as fletchings (feathers on an arrow, namely, they help align the projectile axis with its velocity vector. This reduces the projectile's yaw and hence reduces its aerodynamic drag. In addition, a low yaw angle at target impact helps to maximise the projectile's target penetration. It is typical for projectiles to exit the gun muzzle and enter free flight at some ndn-zero yaw angle. Aerodynamic forces acting on yawed tail fins create a stabilising torque about the projectile's centre of gravity (CG. This torque can be increased by making the fin material lighter. Most conventional long rod penetrators fired from high performance guns have tail fins made from aluminium. However, aluminium can undergo catastrophic oxidation (rapid burning in-bore. Coating aluminium with Al/sub 2/O/sub 3/ {hardcoat prevents ignition of the substrate, provided solid propellant grain impacts do not chip the brittle hardcoat off the surface. Plastic is lighter than aluminium and less exothermic when oxidized. Therefore, other factors aside, it is conceivable that plastic fins could increase projectile stability while incurring less thermal erosion than aluminium. However, thermal loads are not the only concern when considering plastic as an alternative tail fin material. The mechanical strength of plastic is also a critical factor. This paper discusses some of the successes and failures of plastic fins, at least relatively thin fins, for use as KE stabilisers.

  6. Experimental and Transient Thermal Analysis of Heat Sink Fin for CPU processor for better performance

    Science.gov (United States)

    Ravikumar, S.; Subash Chandra, Parisaboina; Harish, Remella; Sivaji, Tallapaneni

    2017-05-01

    The advancement of the digital computer and its utilization day by day is rapidly increasing. But the reliability of electronic components is critically affected by the temperature at which the junction operates. The designers are forced to shorten the overall system dimensions, in extracting the heat and controlling the temperature which focus the studies of electronic cooling. In this project Thermal analysis is carried out with a commercial package provided by ANSYS. The geometric variables and design of heat sink for improving the thermal performance is experimented. This project utilizes thermal analysis to identify a cooling solution for a desktop computer, which uses a 5 W CPU. The design is able to cool the chassis with heat sink joined to the CPU is adequate to cool the whole system. This work considers the circular cylindrical pin fins and rectangular plate heat sink fins design with aluminium base plate and the control of CPU heat sink processes.

  7. Second Law Analysis of the Optimal Fin by Minimum Entropy Generation

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on the entropy generation concept of thermodynamics, this paper established a general theoretical model for the analysis of entropy generation to optimize fms, in which the minimum entropy generation was selected as the object to be studied. The irreversibility due to heat transfer and friction was taken into account so that the minimum entropygeneration number has been analyzed with respect to second law of thermodynamics in the forced cross-flow. The optimum dimensions of cylinder pins were discussed. It's found that the minimum entropy generation number depends on parameters related to the fluid and fin physical parameters. Variations of the minimum entropy generation number with different parameters were analyzed.

  8. Spectroscopic amplifier for pin diode; Amplificador espectroscopico para diodo Pin

    Energy Technology Data Exchange (ETDEWEB)

    Alonso M, M. S.; Hernandez D, V. M.; Vega C, H. R., E-mail: bebe.luna_s@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2014-10-15

    The photodiode remains the basic choice for the photo-detection and is widely used in optical communications, medical diagnostics and field of corpuscular radiation. In detecting radiation it has been used for monitoring radon and its progeny and inexpensive spectrometric systems. The development of a spectroscopic amplifier for Pin diode is presented which has the following characteristics: canceler Pole-Zero (P/Z) with a time constant of 8 μs; constant gain of 57, suitable for the acquisition system; 4th integrator Gaussian order to waveform change of exponential input to semi-Gaussian output and finally a stage of baseline restorer which prevents Dc signal contribution to the next stage. The operational amplifier used is the TLE2074 of BiFET technology of Texas Instruments with 10 MHz bandwidth, 25 V/μs of slew rate and a noise floor of 17 nv/(Hz)1/2. The integrated circuit has 4 operational amplifiers and in is contained the total of spectroscopic amplifier that is the goal of electronic design. The results show like the exponential input signal is converted to semi-Gaussian, modifying only the amplitude according to the specifications in the design. The total system is formed by the detector, which is the Pin diode, a sensitive preamplifier to the load, the spectroscopic amplifier that is what is presented and finally a pulse height analyzer (Mca) which is where the spectrum is shown. (Author)

  9. Transparent polycrystalline cubic silicon nitride

    Science.gov (United States)

    Nishiyama, Norimasa; Ishikawa, Ryo; Ohfuji, Hiroaki; Marquardt, Hauke; Kurnosov, Alexander; Taniguchi, Takashi; Kim, Byung-Nam; Yoshida, Hidehiro; Masuno, Atsunobu; Bednarcik, Jozef; Kulik, Eleonora; Ikuhara, Yuichi; Wakai, Fumihiro; Irifune, Tetsuo

    2017-01-01

    Glasses and single crystals have traditionally been used as optical windows. Recently, there has been a high demand for harder and tougher optical windows that are able to endure severe conditions. Transparent polycrystalline ceramics can fulfill this demand because of their superior mechanical properties. It is known that polycrystalline ceramics with a spinel structure in compositions of MgAl2O4 and aluminum oxynitride (γ-AlON) show high optical transparency. Here we report the synthesis of the hardest transparent spinel ceramic, i.e. polycrystalline cubic silicon nitride (c-Si3N4). This material shows an intrinsic optical transparency over a wide range of wavelengths below its band-gap energy (258 nm) and is categorized as one of the third hardest materials next to diamond and cubic boron nitride (cBN). Since the high temperature metastability of c-Si3N4 in air is superior to those of diamond and cBN, the transparent c-Si3N4 ceramic can potentially be used as a window under extremely severe conditions. PMID:28303948

  10. Turbulent flow in longitudinally finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, D.P.; Hirsa, A.; Jensen, M.K. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Mechanical Engineering, Aeronautical Engineering and Mechanics

    1996-09-01

    An experimental investigation of fully developed, steady, turbulent flow in longitudinally finned tubes has been performed. A two-channel, four-beam, laser-Doppler velocimeter was used to measure velocity profiles and turbulent statistics of air flow seeded with titanium dioxide particles. Mean velocities in axial, radial, and circumferential directions were measured over the tube cross sections and pressure drop in the tubes was measured at six stations along the test section length in order to calculate the fully developed friction factor. Four experimental tube geometries were studied: one smooth tube; two 8-finned tubes (fin height-to-radius ratios of 0.333 and 0.167), and one 16-finned tube (fin height-to-radius ratio of 0.167); detailed measurements were taken at air flow rates corresponding to Reynolds numbers of approximately 5,000, 25,000, and 50,000. Friction factor data were compared to literature results and showed good agreement for both smooth and finned tubes. The wall shear stress distribution varied significantly with reynolds number, particularly for Reynolds numbers of 25,000 and below. Maximum wall shear stress was found at the fin tip and minimum at the fin root. Four secondary flow cells were detected per fin (one in each interfin spacing and one in each core region for each fin); secondary flows were found to be small in comparison to the mean axial flow and relative magnitudes were unaffected by axial flow rate at Reynolds numbers above 25,000. The fluctuating velocities had a structure similar to that of the smooth tube in the core region while the turbulence in the interfin region was greatly reduced. The principal, primary shear stress distribution differed considerably from that of the smooth tube, particularly in the interfin region, and the orientation was found to be approximately in the same direction as the gradient of the mean axial velocity, supporting the use of an eddy viscosity formulation in turbulence modeling.

  11. A comparison of two formulations of the fin efficiency for straight fins

    Science.gov (United States)

    Momoniat, Ebrahim

    2012-04-01

    A formulation of the fin efficiency based on Newton's law of cooling is compared with a formulation based on a ratio of heat transferred from the fin surface to the surrounding fluid to the heat conducted through the base. The first formulation requires that the solution of the nonlinear fin equations for constant heat transfer coefficient and constant thermal conductivity is known, whilst the second formulation of the fin efficiency requires only that a first integral of the model equation is known. This paper shows the first formulation of the fin efficiency contains approximation errors as only power series and approximate solutions to the nonlinear fin equations have been determined. The second formulation of the fin efficiency is exact when the first integrals can be determined.

  12. A comparison of two formulations of the fin efficiency for straight fins

    Institute of Scientific and Technical Information of China (English)

    Ebrahim Momoniat

    2012-01-01

    A formulation of the fin efficiency based on Newton's law of cooling is compared with a formulation based on a ratio of heat transferred from the fin surface to the surrounding fluid to the heat conducted through the base.The first formulation requires that the solution of the nonlinear fin equations for constant heat transfer coefficient and constant thermal conductivity is known,whilst the second formulation of the fin efficiency requires only that a first integral of the model equation is known.This paper shows the first formulation of the fin efficiency contains approximation errors as only power series and approximate solutions to the nonlinear fin equations have been determined.The second formulation of the fin efficiency is exact when the first integrals can be determined.

  13. Uncertainty of pin height measurement for the determination of wear in pin-on-plate test

    DEFF Research Database (Denmark)

    Drago, Nicola; De Chiffre, Leonardo; Poulios, Konstantinos

    2014-01-01

    machine (CMM), achieving an expanded measurement uncertainty (k = 2) better than 1 mm. A simple dedicated fixture adaptable to workshop environment was developed and its metrological capability investigated, estimating an average uncertainty of measurement in the order of 5 mm (k = 2). Fixture......The paper concerns measurement of pin height for the determination of wear in a pin-on-plate (POP) or pin-on-disc (POD) test, where a pin is mounted on a holder that can be fixed on the test rig and removed for measurements. The amount of wear is assessed as difference of pin height before...... and after the test, using the distance between holder plane and pin friction plane as measurand. A series of measurements were performed in connection with POP testing of different friction material pins mounted on an aluminium holder. Pin height measurements were carried out on a coordinate measuring...

  14. Improved shock-detection pin arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D.J.

    1995-08-01

    Shockwave speeds are often measured by comparing arrival times at the tips of electrical shorting pins in a hexagonal array over two elevations (called up and down). In the conventional arrangement, the center pin is solely responsible for measuring the curvature of the wavefront. Without this datum the shock speed cannot be precisely determined. In some experiments this pin fail frequently enough to be a problem. We report a simple rearrangement between up and down designated pins which eliminates the critical reliance on a single.

  15. PIN1 gene variants in Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Siedlecki Janusz

    2009-11-01

    Full Text Available Abstract Background Peptidyl-prolyl isomerase, NIMA-interacting 1 (PIN1 plays a significant role in the brain and is implicated in numerous cellular processes related to Alzheimer's disease (AD and other neurodegenerative conditions. There are confounding results concerning PIN1 activity in AD brains. Also PIN1 genetic variation was inconsistently associated with AD risk. Methods We performed analysis of coding and promoter regions of PIN1 in early- and late-onset AD and frontotemporal dementia (FTD patients in comparison with healthy controls. Results Analysis of eighteen PIN1 common polymorphisms and their haplotypes in EOAD, LOAD and FTD individuals in comparison with the control group did not reveal their contribution to disease risk. In six unrelated familial AD patients four novel PIN1 sequence variants were detected. c.58+64C>T substitution that was identified in three patients, was located in an alternative exon. In silico analysis suggested that this variant highly increases a potential affinity for a splicing factor and introduces two intronic splicing enhancers. In the peripheral leukocytes of one living patient carrying the variant, a 2.82 fold decrease in PIN1 expression was observed. Conclusion Our data does not support the role of PIN1 common polymorphisms as AD risk factor. However, we suggest that the identified rare sequence variants could be directly connected with AD pathology, influencing PIN1 splicing and/or expression.

  16. Tame Kernels of Pure Cubic Fields

    Institute of Scientific and Technical Information of China (English)

    Xiao Yun CHENG

    2012-01-01

    In this paper,we study the p-rank of the tame kernels of pure cubic fields.In particular,we prove that for a fixed positive integer m,there exist infinitely many pure cubic fields whose 3-rank of the tame kernel equal to m.As an application,we determine the 3-rank of their tame kernels for some special pure cubic fields.

  17. Two-dimensional cubic convolution.

    Science.gov (United States)

    Reichenbach, Stephen E; Geng, Frank

    2003-01-01

    The paper develops two-dimensional (2D), nonseparable, piecewise cubic convolution (PCC) for image interpolation. Traditionally, PCC has been implemented based on a one-dimensional (1D) derivation with a separable generalization to two dimensions. However, typical scenes and imaging systems are not separable, so the traditional approach is suboptimal. We develop a closed-form derivation for a two-parameter, 2D PCC kernel with support [-2,2] x [-2,2] that is constrained for continuity, smoothness, symmetry, and flat-field response. Our analyses, using several image models, including Markov random fields, demonstrate that the 2D PCC yields small improvements in interpolation fidelity over the traditional, separable approach. The constraints on the derivation can be relaxed to provide greater flexibility and performance.

  18. Fin shape thermal optimization using Bejan's constuctal theory

    CERN Document Server

    Lorenzini, Giulio

    2011-01-01

    The book contains research results obtained by applying Bejan's Constructal Theory to the study and therefore the optimization of fins, focusing on T-shaped and Y-shaped ones. Heat transfer from finned surfaces is an example of combined heat transfer natural or forced convection on the external parts of the fin, and conducting along the fin. Fin's heat exchange is rather complex, because of variation of both temperature along the fin and convective heat transfer coefficient. Furthermore possible presence of more fins invested by the same fluid flow has to be considered.Classical fin theory tri

  19. Methylmercury in dried shark fins and shark fin soup from American restaurants.

    Science.gov (United States)

    Nalluri, Deepthi; Baumann, Zofia; Abercrombie, Debra L; Chapman, Demian D; Hammerschmidt, Chad R; Fisher, Nicholas S

    2014-10-15

    Consumption of meat from large predatory sharks exposes human consumers to high levels of toxic monomethylmercury (MMHg). There also have been claims that shark fins, and hence the Asian delicacy shark fin soup, contain harmful levels of neurotoxic chemicals in combination with MMHg, although concentrations of MMHg in shark fins are unknown. We measured MMHg in dried, unprocessed fins (n=50) of 13 shark species that occur in the international trade of dried shark fins as well as 50 samples of shark fin soup prepared by restaurants from around the United States. Concentrations of MMHg in fins ranged from 9 to 1720 ng/g dry wt. MMHg in shark fin soup ranged from sharks such as hammerheads (Sphyrna spp.). Consumption of a 240 mL bowl of shark fin soup containing the average concentration of MMHg (4.6 ng/mL) would result in a dose of 1.1 μg MMHg, which is 16% of the U.S. EPA's reference dose (0.1 μg MMHg per 1 kg per day in adults) of 7.4 μg per day for a 74 kg person. If consumed, the soup containing the highest measured MMHg concentration would exceed the reference dose by 17%. While shark fin soup represents a potentially important source of MMHg to human consumers, other seafood products, particularly the flesh of apex marine predators, contain much higher MMHg concentrations and can result in substantially greater exposures of this contaminant for people.

  20. The maize PIN gene family of auxin transporters

    Directory of Open Access Journals (Sweden)

    Cristian eForestan

    2012-02-01

    Full Text Available Auxin is a key regulator of plant development and its differential distribution in plant tissues, established by a polar cell-to-cell transport, can trigger a wide range of developmental processes. A few members of the two families of auxin efflux transport proteins, PIN-formed (PIN and P-glycoprotein (ABCB/PGP, have so far been characterized in maize. Nine new Zea mays auxin efflux carriers PIN family members and two maize PIN-like genes have now been identified. Four members of PIN1 (named ZmPIN1a–d cluster, one gene homologous to AtPIN2 (ZmPIN2, three orthologs of PIN5 (ZmPIN5a–c, one gene paired with AtPIN8 (ZmPIN8, and three monocot-specific PINs (ZmPIN9, ZmPIN10a and b were cloned and the phylogenetic relationships between early land plants, monocots and eudicots PIN proteins investigated, including the new maize PIN proteins. Tissue-specific expression patterns of the twelve maize PIN genes, two PIN-like genes and ZmABCB1, an ABCB auxin efflux carrier, were analyzed using semi-quantitative RT–PCR. ZmPIN gene transcripts have overlapping expression domains in the root apex, during male and female inflorescence differentiation and kernel development. However, some PIN family members have specific tissue localization: ZmPIN1d transcript marks the L1 layer of the SAM and IM during the flowering transition and the monocot-specific ZmPIN9 is expressed in the root endodermis and pericycle. The phylogenetic and gene structure analyses together with the expression pattern of the ZmPIN gene family indicate that subfunctionalization of some maize PINs can be associated to the differentiation and development of monocot-specific organs and tissues and might have occurred after the divergence between dicots and monocots.

  1. Pinning impulsive control algorithms for complex network.

    Science.gov (United States)

    Sun, Wen; Lü, Jinhu; Chen, Shihua; Yu, Xinghuo

    2014-03-01

    In this paper, we further investigate the synchronization of complex dynamical network via pinning control in which a selection of nodes are controlled at discrete times. Different from most existing work, the pinning control algorithms utilize only the impulsive signals at discrete time instants, which may greatly improve the communication channel efficiency and reduce control cost. Two classes of algorithms are designed, one for strongly connected complex network and another for non-strongly connected complex network. It is suggested that in the strongly connected network with suitable coupling strength, a single controller at any one of the network's nodes can always pin the network to its homogeneous solution. In the non-strongly connected case, the location and minimum number of nodes needed to pin the network are determined by the Frobenius normal form of the coupling matrix. In addition, the coupling matrix is not necessarily symmetric or irreducible. Illustrative examples are then given to validate the proposed pinning impulsive control algorithms.

  2. Ice formation around isothermal radial finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, K.A.R.; Henriquez, J.R.; Moura, L.F.M.; Ganzarolli, M.M. [UNICAMP-FEM-DETF, Campinas (Brazil)

    2000-04-01

    The present study presents a thermal numerical model for the solidification of Phase Change Material around a radially finned tube with a constant wall temperature. The model is based upon a pure conduction formulation and the enthalpy method. The finite difference approach and the alternating direction implicit scheme are used to discretize the system of equations and the associated boundary, initial and final conditions. Numerical experiments were realized to optimise the numerical code. Numerical simulations were performed to investigate the effects, of the number of fins, fin thickness, fin material, aspect ratio of the tube arrangement and the tube wall temperature. Graphical results were presented, discussed and equations relating the effect of each of the variables on the time for complete solidification are also presented. (author)

  3. Genetic algorithm optimization for finned channel performance

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Compared to a smooth channel, a finned channel provides a higher heat transfer coefficient; increasing the fin height enhances the heat transfer. However, this heat transfer enhancement is associated with an increase in the pressure drop. This leads to an increased pumping power requirement so that one may seek an optimum design for such systems. The main goal of this paper is to define the exact location and size of fins in such a way that a minimal pressure drop coincides with an optimal heat transfer based on the genetic algorithm. Each fin arrangement is considered a solution to the problem(an individual for genetic algorithm). An initial population is generated randomly at the first step. Then the algorithm has been searched among these solutions and made new solutions iteratively by its functions to find an optimum design as reported in this article.

  4. Nanoscale pinning effect evaluated from deformed nanobubbles

    Science.gov (United States)

    Teshima, Hideaki; Nishiyama, Takashi; Takahashi, Koji

    2017-01-01

    Classical thermodynamics theory predicts that nanosized bubbles should disappear in a few hundred microseconds. The surprisingly long lifetime and stability of nanobubbles are therefore interesting research subjects. It has been proposed that the stability of nanobubbles arises through pinning of the three-phase contact line, which results from intrinsic nanoscale geometrical and chemical heterogeneities of the substrate. However, a definitive explanation of nanobubble stability is still lacking. In this work, we examined the stability mechanism by introducing a "pinning force." We investigated nanobubbles at a highly ordered pyrolytic graphite/pure water interface by peak force quantitative nano-mechanical mapping and estimated the pinning force and determined its maximum value. We then observed the shape of shrinking nanobubbles. Because the diameter of the shrinking nanobubbles was pinned, the height decreased and the contact angle increased. This phenomenon implies that the stability results from the pinning force, which flattens the bubble through the pinned three-phase contact line and prevents the Laplace pressure from increasing. The pinning force can also explain the metastability of coalesced nanobubbles, which have two semispherical parts that are joined to form a dumbbell-like shape. The pinning force of the semispherical parts was stronger than that of the joint region. This result demonstrates that the contact line of the semispherical parts is pinned strongly to keep the dumbbell-like shape. Furthermore, we proposed a nanobubble generation mechanism for the solvent-exchange method and explained why the pinning force of large nanobubbles was not initially at its maximum value, as it was for small nanobubbles.

  5. Curvature Could Give Fish Fins Their Strength

    National Research Council Canada - National Science Library

    2017-01-01

    ... maneuverable is by having the ability to generate varying amounts of force on the water when flapping a fin,” said Shreyas Mandre, an assistant professor in Brown’s School of Engineering and a co-author of the research. “We think that fish modulate curvature at the base of the fin to make it stiffer or softer, which alters the force they gene...

  6. PHASE CHANGE AROUND A FINNED TUBE

    OpenAIRE

    EREK, Aytunç

    2003-01-01

    This study presents the heat transfer enhancement in the thermal energy storage system by using radially finned tube. The solution of the system consists of the solving the equations of the heat transfer fluid (HTF), the pipe wall and fin, and the phase change material (PCM) as one domain. The control volume finite difference approach and the semi implicit solver (SIS) are used to solve the equations. Fully developed velocity distribution is taken in the HTF. Flow parameters (Re number and in...

  7. Cubical local partial orders on cubically subdivided spaces - Existence and construction

    DEFF Research Database (Denmark)

    Fajstrup, Lisbeth

    2006-01-01

    The geometric models of higher dimensional automata (HDA) and Dijkstra's PV-model are cubically subdivided topological spaces with a local partial order. If a cubicalization of a topological space is free of immersed cubic Möbius bands, then there are consistent choices of direction in all cubes...

  8. Cubical local partial orders on cubically subdivided spaces - existence and construction

    DEFF Research Database (Denmark)

    Fajstrup, Lisbeth

    The geometric models of Higher Dimensional Automata and Dijkstra's PV-model are cubically subdivided topological spaces with a local partial order. If a cubicalization of a topological space is free of immersed cubic Möbius bands, then there are consistent choices of direction in all cubes...

  9. CFD Analysis of Plate Fin Tube Heat Exchanger for Various Fin Inclinations

    OpenAIRE

    2014-01-01

    ANSYS Fluent software is used for three dimensional CFD simulations to investigate heat transfer and fluid flow characteristics of six different fin angles with plain fin tube heat exchangers. The numerical simulation of the fin tube heat exchanger was performed by using a three dimensional numerical computation technique. Geometry of model is created and meshed by using ANSYS Workbench software. To solve the equation for the fluid flow and heat transfer analysis ANSYS FLUENT ...

  10. Pattern Reconfigurable Patch Antenna menggunakan Edge Shorting Pin dan Symmetrical Control Pin

    Directory of Open Access Journals (Sweden)

    DWI ANDI NURMANTRIS

    2016-02-01

    Full Text Available Abstrak Metode baru dalam mendesain suatu pattern reconfigurable antenna telah diteliti. Penelitian ini fokus pada optimasi antena patch lingkaran single layer pencatuan probe koaksial dengan mengintegrasikan 24 switch/shorting pin pada sisi patch yang disebut edge shorting pin dan 8 shorting pin membentuk lingkaran dengan radius tertentu dan selanjutnya disebut symmetrical control pin yang fungsinya sebagai metode penyepadan impedansi. Algoritma Genetika yang dikombinasikan dengan Finite Element Software digunakan untuk mengoptimasi kombinasi  switch, radius lingkaran symmetrical control pin, dan radius patch untuk mendapatkan kemampuan pattern reconfigurability. Antena ini menghasilkan 8 kemungkinan arah radiasi azzimuth dengan resolusi 45o dan arah elevasi 30o pada frekuensi 2,4 Ghz. Optimasi, simulasi, fabrikasi, dan pengukuran dilakukan untuk memverifikasi hasil penelitian. Kata kunci: Patch Lingkaran, Edge Shorting Pin, Symmetrical Control Pin, Algoritma Genetika, Pattern Reconfigurable   Abstract New method for desaining pattern reconfigurable antenna was studied. This study focuses on the optimization of a single layer circular patch antenna with probe feed by integrating the 24 switch / shorting pin on the side of the patch that called Edge Shorting Pins and 8 shorting pins form circular line in such radius that called Symmetrical Control Pins as a impedance matching method. Genetic algorithm combined with the Finite Element Software is used to optimize the switch combination, the radius of circular line of symmetrical control pins, and the patch radius to obtain a pattern reconfigurability capabilities. This antenna produces 8 possible directions of azimuth radiation with a resolution of 45o and 30o elevation direction at a frequency of 2.4 GHz. Optimization, simulation, fabrication, and measurement was done to verify the results. Keywords: Circular Patch, Edge Shorting Pin, Symmetrical Control Pin, Genetic Algorithm, Pattern

  11. Effects of Auxins on PIN-FORMED2 (PIN2) Dynamics Are Not Mediated by Inhibiting PIN2 Endocytosis.

    Science.gov (United States)

    Jásik, Ján; Bokor, Boris; Stuchlík, Stanislav; Mičieta, Karol; Turňa, Ján; Schmelzer, Elmon

    2016-10-01

    By using the photoconvertible fluorescence protein Dendra2 as a tag we demonstrated that neither the naturally occurring auxins indole-3-acetic acid and indole-3-butyric acid, nor the synthetic auxin analogs 1-naphthaleneacetic acid and 2,4-dichlorophenoxyacetic acid nor compounds inhibiting polar auxin transport such as 2,3,5-triiodobenzoic acid and 1-N-naphthylphthalamic acid, were able to inhibit endocytosis of the putative auxin transporter PIN-FORMED2 (PIN2) in Arabidopsis (Arabidopsis thaliana) root epidermis cells. All compounds, except Indole-3-butyric acid, repressed the recovery of the PIN2-Dendra2 plasma membrane pool after photoconversion when they were used in high concentrations. The synthetic auxin analogs 1-naphthaleneacetic acid and 2,4-dichlorophenoxyacetic acid showed the strongest inhibition. Auxins and auxin transport inhibitors suppressed also the accumulation of both newly synthesized and endocytotic PIN2 pools in Brefeldin A compartments (BFACs). Furthermore, we demonstrated that all compounds are also interfering with BFAC formation. The synthetic auxin analogs caused the highest reduction in the number and size of BFACs. We concluded that auxins and inhibitors of auxin transport do affect PIN2 turnover in the cells, but it is through the synthetic rather than the endocytotic pathway. The study also confirmed inappropriateness of the BFA-based approach to study PIN2 endocytosis because the majority of PIN2 accumulating in BFACs is newly synthesized and not derived from the plasma membrane. © 2016 American Society of Plant Biologists. All Rights Reserved.

  12. Thermal transport in oblique finned microminichannels

    CERN Document Server

    Fan, Yan; Singh, Pawan Kumar; Lee, Yong Jiun

    2015-01-01

    The main aim of this book is to introduce and give an overview of a novel, easy, and highly effective heat transfer augmentation technique for single-phase micro/minichannel heat sink. The specific objectives of the volume are to: Introduce a novel planar oblique fin microchannel and cylindrical oblique fin minichannel heat sink design using passive heat transfer enhancement techniques  Investigate the thermal transport in both planar and cylindrical oblique fin structures through numerical simulation and systematic experimental studies. Evaluate the feasibility of employing the proposed solution in cooling non-uniform heat fluxes and hotspot suppression Conduct the similarity analysis and parametric study to obtain empirical correlations to evaluate the total heat transfer rate of the oblique fin heat sink Investigate the flow mechanism and optimize the dimensions of cylindrical oblique fin heat sink Investigate the influence of edge effect on flow and temperature uniformity in these oblique fin chan...

  13. The art of fin regeneration in zebrafish.

    Science.gov (United States)

    Pfefferli, Catherine; Jaźwińska, Anna

    2015-04-01

    The zebrafish fin provides a valuable model to study the epimorphic type of regeneration, whereby the amputated part of the appendage is nearly perfectly replaced. To accomplish fin regeneration, two reciprocally interacting domains need to be established at the injury site, namely a wound epithelium and a blastema. The wound epithelium provides a supporting niche for the blastema, which contains mesenchyme-derived progenitor cells for the regenerate. The fate of blastemal daughter cells depends on their relative position with respect to the fin margin. The apical compartment of the outgrowth maintains its undifferentiated character, whereas the proximal descendants of the blastema progressively switch from the proliferation program to the morphogenesis program. A delicate balance between self-renewal and differentiation has to be continuously adjusted during the course of regeneration. This review summarizes the current knowledge about the cellular and molecular mechanisms of blastema formation, and discusses several studies related to the regulation of growth and morphogenesis during fin regeneration. A wide range of canonical signaling pathways has been implicated during the establishment and maintenance of the blastema. Epigenetic mechanisms play a crucial role in the regulation of cellular plasticity during the transition between differentiation states. Ion fluxes, gap-junctional communication and protein phosphatase activity have been shown to coordinate proliferation and tissue patterning in the caudal fin. The identification of the downstream targets of the fin regeneration signals and the discovery of mechanisms integrating the variety of input pathways represent exciting future aims in this fascinating field of research.

  14. CLASSIFICATION OF CUBIC PARAMETERIZED HOMOGENEOUS VECTOR FIELDS

    Institute of Scientific and Technical Information of China (English)

    Karnal H.Yasir; TANG Yun

    2002-01-01

    In this paper the cubic homogeneous parameterized vector fields are studied.The classification of the phase portrait near the critical point is presented. This classification is an extension of the result given by Takens to the cubic homogeneous parameterized vector fields with six parameters.

  15. CLASSIFICATION OF CUBIC PARAMETERIZED HOMOGENEOUS VECTOR FIELDS

    Institute of Scientific and Technical Information of China (English)

    KamalH.Yasir; TNAGYun

    2002-01-01

    In this paper the cubic homogeneous parameterized vector fields are studied.The classification of the phase portrait near the critical point is presented.This classification is an extension of the result given by takens to the cubic homogeneous parameterized vector fields with six parameters.

  16. Studi Analitik dan Numerik Perpindahan Panas pada Fin Trapesium (Studi Kasus pada Finned Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Ahmad Zaini

    2013-09-01

    Full Text Available Penambahan fin pada pipa penukar kalor merupakan suatu upaya memperbesar perpindahan kalor konduksi dan konveksi, dengan cara memperluas bidang geometri. Pada penelitian ini dianalisa secara analitik dan numerik perpindahan kalor pada fin dengan profil longitudinal tidak seragam atau berubah terhadap jarak dari dasar fin, dengan memvariasikan ketebalan ujung fin. Hasil dari kedua studi ini tidak jauh berbeda, pada keduanya menjelaskan bahwa fin dengan ketebalan ujung 0,9 mm (fin trapesium terbalik paling baik dari 5 variasi lainnya; serta perubahan temperatur paling besar terjadi pada sepertiga pertama dari panjang  fin, ini artinya pelepasan kalor terbesar terjadi pada daerah tersebut. Perbedaannya adalah pada persentase penurunan temperatur sepanjang  fin terhadap temperatur dasar fin, untuk ketebalan 0,9 mm pada studi analitik sebesar 91,92% dan pada studi numerik sebesar 91,78%. Hal ini berarti metode penyelesaian persamaan diferensial orde 2 dengan koefisien variabel dengan cara pembedahan koefisien variabel pada ODE, sudah benar dan valid. Namun bila ditinjau dari waktu yang diperlukan untuk komputasinya, studi analitik membutuhkan waktu lebih lama. Waktu yang diperlukan dalam komputasinya tergantung dari fungsi koefisien variabel.

  17. Performance study of a fin and tube heat exchanger with different fin geometry

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2016-01-01

    This study analyses the effect of different fin geometries on the heat transfer and pressure loss characteristics of a fin and tube heat exchanger. A numerical investigation is carried out on liquid–gas type double-finned tube heat exchanger under cross-flow condition. Three different cross...... and pressure loss characteristics such as Nusselt number, Euler number, and efficiency index are determined and utilized to compare the performance of different fin geometries. The results obtained from the models are verified using experimentally developed correlations. The results obtained from the numerical...

  18. Pinning controllability of complex networks with community structure.

    Science.gov (United States)

    Miao, Qingying; Tang, Yang; Kurths, Jürgen; Fang, Jian-an; Wong, W K

    2013-09-01

    In this paper, we study the controllability of networks with different numbers of communities and various strengths of community structure. By means of simulations, we show that the degree descending pinning scheme performs best among several considered pinning schemes under a small number of pinned nodes, while the degree ascending pinning scheme is becoming more powerful by increasing the number of pinned nodes. It is found that increasing the number of communities or reducing the strength of community structure is beneficial for the enhancement of the controllability. Moreover, it is revealed that the pinning scheme with evenly distributed pinned nodes among communities outperforms other kinds of considered pinning schemes.

  19. 14 CFR 23.445 - Outboard fins or winglets.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Outboard fins or winglets. 23.445 Section... § 23.445 Outboard fins or winglets. (a) If outboard fins or winglets are included on the horizontal... with loads induced by the fins or winglets and moments or forces exerted on the horizontal surfaces...

  20. Some aspects of film condensation of steam on finned tubes

    OpenAIRE

    Coumes, James M.

    1989-01-01

    Approved for public release; distribution is unlimited Heat-transfer measurements were made for filmwise condensation of steam on smooth tubes and finned tubes with rectangular-shaped fins. The influence of fin root diameter on a single horizontal finned tube was examined by taking data for two families of tubes whose fin root diameters were 12.7 and 19.05 mm. Each family of tubes had fins that were 1 mm thick and 1 mm high but with fin spacings of 0.25, 0.50, 1.0, 1.5, 2.0, and 4.0 mm. ...

  1. Flow and heat transfer in compact offset strip fin surfaces

    Institute of Scientific and Technical Information of China (English)

    Junqi DONG; Jiangping CHEN; Zhijiu CHEN

    2008-01-01

    Experimental studies of air-side heat transfer and pressure drop characteristics of offset strip fins and flat tube heat exchangers were performed. A series of tests were conducted for 9 heat exchangers with different fin space, fin height, fin strip length and flow length, at a constant tube-side water flow rate of 2.5 m3/h. The char-acteristics of the heat transfer and pressure drop of differ-ent fin space, fin height and fin length were analyzed and compared. The curves of the heat transfer coefficients vs. The pumping power per unit frontal area were then plot-ted. Moreover, the enhanced heat transfer mechanism of offset strip fins was analyzed using field synergy theory. The results showed that fin length and flow length have more obviously effect on the thermal hydraulic character-istics of offset strip fins.

  2. Bare and boron-doped cubic silicon carbide nanowires for electrochemical detection of nitrite sensitively.

    Science.gov (United States)

    Yang, Tao; Zhang, Liqin; Hou, Xinmei; Chen, Junhong; Chou, Kuo-Chih

    2016-04-25

    Fabrication of eletrochemical sensors based on wide bandgap compound semiconductors has attracted increasing interest in recent years. Here we report for the first time electrochemical nitrite sensors based on cubic silicon carbide (SiC) nanowires (NWs) with smooth surface and boron-doped cubic SiC NWs with fin-like structure. Multiple techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS) were used to characterize SiC and boron-doped SiC NWs. As for the electrochemical behavior of both SiC NWs electrode, the cyclic voltammetric results show that both SiC electrodes exhibit wide potential window and excellent electrocatalytic activity toward nitrite oxidation. Differential pulse voltammetry (DPV) determination reveals that there exists a good linear relationship between the oxidation peak current and the concentration in the range of 50-15000 μmoL L(-1) (cubic SiC NWs) and 5-8000 μmoL L(-1) (B-doped cubic SiC NWs) with the detection limitation of 5 and 0.5 μmoL L(-1) respectively. Compared with previously reported results, both as-prepared nitrite sensors exhibit wider linear response range with comparable high sensitivity, high stability and reproducibility.

  3. Ultrahard nanotwinned cubic boron nitride.

    Science.gov (United States)

    Tian, Yongjun; Xu, Bo; Yu, Dongli; Ma, Yanming; Wang, Yanbin; Jiang, Yingbing; Hu, Wentao; Tang, Chengchun; Gao, Yufei; Luo, Kun; Zhao, Zhisheng; Wang, Li-Min; Wen, Bin; He, Julong; Liu, Zhongyuan

    2013-01-17

    Cubic boron nitride (cBN) is a well known superhard material that has a wide range of industrial applications. Nanostructuring of cBN is an effective way to improve its hardness by virtue of the Hall-Petch effect--the tendency for hardness to increase with decreasing grain size. Polycrystalline cBN materials are often synthesized by using the martensitic transformation of a graphite-like BN precursor, in which high pressures and temperatures lead to puckering of the BN layers. Such approaches have led to synthetic polycrystalline cBN having grain sizes as small as ∼14 nm (refs 1, 2, 4, 5). Here we report the formation of cBN with a nanostructure dominated by fine twin domains of average thickness ∼3.8 nm. This nanotwinned cBN was synthesized from specially prepared BN precursor nanoparticles possessing onion-like nested structures with intrinsically puckered BN layers and numerous stacking faults. The resulting nanotwinned cBN bulk samples are optically transparent with a striking combination of physical properties: an extremely high Vickers hardness (exceeding 100 GPa, the optimal hardness of synthetic diamond), a high oxidization temperature (∼1,294 °C) and a large fracture toughness (>12 MPa m(1/2), well beyond the toughness of commercial cemented tungsten carbide, ∼10 MPa m(1/2)). We show that hardening of cBN is continuous with decreasing twin thickness down to the smallest sizes investigated, contrasting with the expected reverse Hall-Petch effect below a critical grain size or the twin thickness of ∼10-15 nm found in metals and alloys.

  4. Cubic III-nitrides: potential photonic materials

    Science.gov (United States)

    Onabe, K.; Sanorpim, S.; Kato, H.; Kakuda, M.; Nakamura, T.; Nakamura, K.; Kuboya, S.; Katayama, R.

    2011-01-01

    The growth and characterization of some cubic III-nitride films on suitable cubic substrates have been done, namely, c- GaN on GaAs by MOVPE, c-GaN and c-AlGaN on MgO by RF-MBE, and c-InN and c-InGaN (In-rich) on YSZ by RFMBE. This series of study has been much focused on the cubic-phase purity as dependent on the respective growth conditions and resulting electrical and optical properties. For c-GaN and c-InN films, a cubic-phase purity higher than 95% is attained in spite of the metastable nature of the cubic III-nitrides. However, for c-AlGaN and c-InGaN films, the cubic-phase purity is rapidly degraded with significant incorporation of the hexagonal phase through stacking faults on cubic {111} faces which may be exposed on the roughened growing or substrate surface. It has been shown that the electron mobilities in c-GaN and c-AlGaN films are much related to phase purity.

  5. Crystallization fouling of finned tubes during pool boiling: effect of fin density

    Energy Technology Data Exchange (ETDEWEB)

    Esawy, M.; Malayeri, M.R. [University of Stuttgart, Institute for Thermodynamics and Thermal Engineering (ITW), Stuttgart (Germany); Mueller-Steinhagen, H. [University of Stuttgart, Institute for Thermodynamics and Thermal Engineering (ITW), Stuttgart (Germany); German Aerospace Centre (DLR), Institute of Technical Thermodynamics, Stuttgart (Germany)

    2010-11-15

    Bubble characteristics such as density, size, frequency and motion are key factors that contribute to the superiority of nucleate pool boiling over other modes of heat transfer. Nevertheless, if heat transfer occurs in an environment prone to fouling, the very same parameters may lead to accelerated deposit formation due to concentration effects beneath the growing bubbles. This has led to the widely accepted design recommendation to maintain the heat transfer surface temperature below the boiling point if fouling may occur, e.g., in seawater desalination. The present paper aims at investigating the formation of deposits on finned tubes during nucleate pool boiling of CaSO{sub 4} solutions. The test finned tubes are low finned tubes with fin densities of 19 and 26 fins/in. made from Cu-Ni. The fouling experiments were carried out at atmospheric pressure for different heat fluxes ranging from 100 to 300 kW/m{sup 2} and a CaSO{sub 4} concentration of 1.6 g/L. For the sake of comparison, similar runs were performed with smooth stainless steel tubes. The results show that: (1) the fouling resistance decreases with increasing fin density, (2) fouling on the finned tubes was reduced with increasing nucleate boiling activity and (3) if any fouling layer occurred on the finned tubes it could be removed easily. (orig.)

  6. Airside performances of finned eight-tube heat exchangers

    Science.gov (United States)

    Li, Cheng; Li, Junming

    2016-11-01

    For applications in the relatively low temperature refrigeration systems with large constant temperature bath, the present work performed the experimental studies on the airside performances of the staggered finned eight-tube heat exchangers with large fin pitches. The airside heat transfer coefficients and pressure drops for three fin types and two fin pitches are obtained and analyzed. The heat transfer enhancement with louver fins is 11-16 % higher than the flat fins and that with sinusoidal corrugated fins is 1.1-3.4 % higher than the flat fins. Higher Re brings larger enhancement for various fins. Fin pitches show weak influence on heat transfer for eight tube rows. However, effects of fin pitch on heat transfer for both the sinusoidal corrugation and the louvered fin are larger than the flat fins and they are different from those for N ≤ 6. Airside Colburn j factor are compared with previous and it could be concluded that the airside j factor is almost constant for finned tube heat exchangers with eight tubes and large fin pitches, when Re is from 250 to 2500. The results are different from previous studies for fewer tube rows.

  7. Role of Pectoral Fin Flexibility in Robotic Fish Performance

    Science.gov (United States)

    Bazaz Behbahani, Sanaz; Tan, Xiaobo

    2017-08-01

    Pectoral fins play a vital role in the maneuvering and locomotion of fish, and they have become an important actuation mechanism for robotic fish. In this paper, we explore the effect of flexibility of robotic fish pectoral fins on the robot locomotion performance and mechanical efficiency. A dynamic model for the robotic fish is presented, where the flexible fin is modeled as multiple rigid elements connected via torsional springs and dampers. Blade element theory is used to capture the hydrodynamic force on the fin. The model is validated with experimental results obtained on a robotic fish prototype, equipped with 3D-printed fins of different flexibility. The model is then used to analyze the impacts of fin flexibility and power/recovery stroke speed ratio on the robot swimming speed and mechanical efficiency. It is found that, in general, flexible fins demonstrate advantages over rigid fins in speed and efficiency at relatively low fin-beat frequencies, while rigid fins outperform flexible fins at higher frequencies. For a given fin flexibility, the optimal frequency for speed performance differs from the optimal frequency for mechanical efficiency. In addition, for any given fin, there is an optimal power/recovery stroke speed ratio, typically in the range of 2-3, that maximizes the speed performance. Overall, the presented model offers a promising tool for fin flexibility and gait design, to achieve speed and efficiency objectives for robotic fish actuated with pectoral fins.

  8. Blue shark Prionace glauca fin-to-carcass-mass ratios in Spain and implications for finning ban enforcement.

    Science.gov (United States)

    Santana-Garcon, J; Fordham, S; Fowler, S

    2012-04-01

    This study examines the processing of fins from blue sharks Prionace glauca caught by the Spanish longline fleet and landed in Vigo, Spain, and implications of these practices for enforcing the E.U. ban on shark finning, which relies on a maximum fin-to-carcass-mass ratio. Two major sources of variability in fin-to-carcass ratios are quantified and discussed: (1) the fin set (type and number of fins retained from each shark) and (2) the cutting method used to separate fins from carcasses. The significant differences in fin-to-carcass-mass ratios between fin sets or cutting procedure demonstrates that the ratio limit is problematic and, conclusively, in order to facilitate proper enforcement, fishermen should be required to land all sharks with the fins still naturally attached to the bodies. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  9. Cubic Curves, Finite Geometry and Cryptography

    CERN Document Server

    Bruen, A A; Wehlau, D L

    2011-01-01

    Some geometry on non-singular cubic curves, mainly over finite fields, is surveyed. Such a curve has 9,3,1 or 0 points of inflexion, and cubic curves are classified accordingly. The group structure and the possible numbers of rational points are also surveyed. A possible strengthening of the security of elliptic curve cryptography is proposed using a `shared secret' related to the group law. Cubic curves are also used in a new way to construct sets of points having various combinatorial and geometric properties that are of particular interest in finite Desarguesian planes.

  10. Generalized Vaidya spacetime for cubic gravity

    CERN Document Server

    Ruan, Shan-Ming

    2015-01-01

    We present a kind of generalized Vaidya solutions of a new cubic gravity in five dimensions whose field equations in spherically spacetime are always second order like the Lovelock gravity. We also study the thermodynamics of its apparent horizon and get its entropy expression and generalized Misner-Sharp energy. Finally we present the first law and second law hold in this gravity. Although all the results are analogue to those in Lovelock gravity, we in fact introduce the contribution of new cubic term in five dimensions where cubic Lovelock term is just zero.

  11. Cubical sets as a classifying topos

    DEFF Research Database (Denmark)

    Spitters, Bas

    Coquand’s cubical set model for homotopy type theory provides the basis for a computational interpretation of the univalence axiom and some higher inductive types, as implemented in the cubical proof assistant. We show that the underlying cube category is the opposite of the Lawvere theory of De...... Morgan algebras. The topos of cubical sets itself classifies the theory of ‘free De Morgan algebras’. This provides us with a topos with an internal ‘interval’. Using this interval we construct a model of type theory following van den Berg and Garner. We are currently investigating the precise relation...

  12. Performance study of a fin and tube heat exchanger with different fin geometry

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2016-01-01

    This study analyses the effect of different fin geometries on the heat transfer and pressure loss characteristics of a fin and tube heat exchanger. A numerical investigation is carried out on liquid–gas type double-finned tube heat exchanger under cross-flow condition. Three different cross......-sections namely: a) Rectangular, b) Trapezoidal, c) Triangular are adopted to define the fin geometry. The CFD simulations are performed to incorporate coupled steady state conjugate heat transfer with the turbulent flow phenomenon for the Reynolds number in the range of 5000-13000. Dimensionless heat transfer...... and pressure loss characteristics such as Nusselt number, Euler number, and efficiency index are determined and utilized to compare the performance of different fin geometries. The results obtained from the models are verified using experimentally developed correlations. The results obtained from the numerical...

  13. The problem of the open safety pin.

    Science.gov (United States)

    Marsh, B R

    1975-01-01

    The open safety pin lodged in the stomach or esophagus presents a challenge to surgical judgment and technical skill. Most foreign bodies causing trouble lodge in the esophagus. Once in the stomach, uneventful passage can be expected in 80 to 90% of cases. Active intervention is reserved for those where intestinal performation is likely or where there is failure to progress. We have used the fiberesophagoscope to remove three open safety pins from the stomachs of two patients whose symptoms and threat of perforation required intervention. The microbiopsy forceps was used successfully to retrieve the open pins, but a newly developed grasping forceps for use with the fiberesophagoscope now provides a more secure hold on such foreign bodies. Rigid instruments retain their value for selected cases, but the flexible equipment now provides an important advance in the management of the open safety pin in the stomach.

  14. Pinning Synchronization of Switched Complex Dynamical Networks

    Directory of Open Access Journals (Sweden)

    Liming Du

    2015-01-01

    Full Text Available Network topology and node dynamics play a key role in forming synchronization of complex networks. Unfortunately there is no effective synchronization criterion for pinning synchronization of complex dynamical networks with switching topology. In this paper, pinning synchronization of complex dynamical networks with switching topology is studied. Two basic problems are considered: one is pinning synchronization of switched complex networks under arbitrary switching; the other is pinning synchronization of switched complex networks by design of switching when synchronization cannot achieved by using any individual connection topology alone. For the two problems, common Lyapunov function method and single Lyapunov function method are used respectively, some global synchronization criteria are proposed and the designed switching law is given. Finally, simulation results verify the validity of the results.

  15. Comparative Study of Effect of Fin Arrangement on Propulsion Performance of Bio-inspired Underwater Vehicles with Multiple SMA Fins

    Directory of Open Access Journals (Sweden)

    Jian-hui He

    2015-09-01

    Full Text Available A biologically inspired underwater vehicle (BIUV was built using multiple lightweight bio inspired shape memory alloy (SMA fins. An unsteady 3D computational fluid dynamics (CFD method using an unstructured, grid-based, and unsteady Navier-Stokes solver with automatic adaptive re-meshing was adopted to compute unsteady flow. The hydrodynamics of multiple fins at a certain Reynolds number (Re = Uc/ν, where U is the upstream flow velocity, c is the chord length, and ν is the kinematic viscosity was studied and simulated using CFD to estimate hydrodynamic forces and characterize flow and vortex patterns created by the fins. Two common arrangements of multiple fins on the BIUV were considered: a posterior fin that is parallel to the anterior fins (case 1 and a posterior fin that is perpendicular to the anterior fins (case 2. First, the influence of the distance between two anterior undulating fins on the propulsion performance of both arrangements of multiple fins on the BIUV was investigated. The effect of the distance between the anterior undulating fins and the posterior oscillating fin was also analysed. The length of the posterior oscillating fin was varied and the fin surface area was held constant (24 mm2 to illustrate the influence of this parameter. Finally, the effect of frequency, amplitude, and wave number of anterior undulating fins on the non-dimensional drag coefficient of the posterior oscillating fin was investigated. Based on the flow structures, the reasons for the different performances of the BIUV are discussed. BIUV performances largely depend on the arrangements of multiple fins and the gap between the fins. Dimension and kinematic parameters also affect the performance of the BIUV. The results provide a physical insight into the understanding of fin interaction in fish or BIUVs that are propelled by multiple fins.

  16. Flux pinning in superconductors. 2. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Teruo [Kyushu Institute of Technology, Iizuka, Fukuoka (Japan). Dept. of Computer Science and Electronics

    2014-04-01

    Ideal for graduate students studying superconductivity and experts alike. Written by a researcher with more than 30 years experience in the field. All chapters are completely revised. The book covers the flux pinning mechanisms and properties and the electromagnetic phenomena caused by the flux pinning common for metallic, high-Tc and MgB2 superconductors. The condensation energy interaction known for normal precipitates or grain boundaries and the kinetic energy interaction proposed for artificial Nb pins in Nb-Ti, etc., are introduced for the pinning mechanism. Summation theories to derive the critical current density are discussed in detail. Irreversible magnetization and AC loss caused by the flux pinning are also discussed. The loss originally stems from the ohmic dissipation of normal electrons in the normal core driven by the electric field induced by the flux motion. The readers will learn why the resultant loss is of hysteresis type in spite of such mechanism. The influence of the flux pinning on the vortex phase diagram in high Tc superconductors is discussed, and the dependencies of the irreversibility field are also described on other quantities such as anisotropy of superconductor, specimen size and electric field strength. Recent developments of critical current properties in various high-Tc superconductors and MgB2 are introduced. Other topics are: singularity in the case of transport current in a parallel magnetic field such as deviation from the Josephson relation, reversible flux motion inside pinning potentials which causes deviation from the critical state model prediction, the concept of the minimization of energy dissipation in the flux pinning phenomena which gives the basis for the critical state model, etc. Significant reduction in the AC loss in AC wires with very fine filaments originates from the reversible flux motion which is dominant in the two-dimensional pinning. The concept of minimum energy dissipation explains also the behavior

  17. Anisotropic flux pinning in high Tc superconductors

    Science.gov (United States)

    Koleśnik, S.; Igalson, J.; Skośkiewicz, T.; Szymczak, R.; Baran, M.; Pytel, K.; Pytel, B.

    1995-02-01

    In this paper we present a comparison of the results of FC magnetization measurements on several PbSr(Y,Ca)CuO crystals representing various levels of flux pinning. The pinning centers in our crystals have been set up during the crystal growth process or introduced by neutron irradiation. Some possible explanations of the observed effects, including surface barrier, flux-center distribution and sample-shape effects, are discussed.

  18. Open safety pin in the nasal cavity.

    Science.gov (United States)

    Sen, I; Sikder, B; Sinha, R; Paul, R

    2004-04-01

    Foreign bodies in the nasal cavity are common-day occurrences in Otolaryngologic practice. But an open safety pin in nose with it' s sharp end directed towards roof is a rare incidence, and available literature is silent about this presentation; it is probably, the first of it' s kind being reported. Two cases of safety pins inside the nasal cavity, one open and the other closed, have been presented here with a brief review of literature.

  19. Open safety pin in the nasal cavity

    OpenAIRE

    Sen, I; Sikder, B.; R. Sinha; Paul, R

    2004-01-01

    Foreign bodies in the nasal cavity are common-day occurrences in Otolaryngologic practice. But an open safety pin in nose with it’ s sharp end directed towards roof is a rare incidence, and available literature is silent about this presentation; it is probably, the first of it’ s kind being reported. Two cases of safety pins inside the nasal cavity, one open and the other closed, have been presented here with a brief review of literature.

  20. IMp: The customizable LEGO® Pinned Insect Manipulator

    Directory of Open Access Journals (Sweden)

    Steen Dupont

    2015-02-01

    Full Text Available We present a pinned insect manipulator (IMp constructed of LEGO® building bricks with two axes of movement and two axes of rotation. In addition we present three variants of the IMp to emphasise the modular design, which facilitates resizing to meet the full range of pinned insect specimens, is fully customizable, collapsible, affordable and does not require specialist tools or knowledge to assemble.

  1. Memory-only selection of dictionary PINs

    OpenAIRE

    Stanek, Martin

    2014-01-01

    We estimate the security of dictionary-based PINs (Personal Identification Numbers) that a user selects from his/her memory without any additional aids. The estimates take into account the distribution of words in source language. We use established security metrics, such as entropy, guesswork, marginal guesswork and marginal success rate. The metrics are evaluated for various scenarios -- aimed at improving the security of the produced PINs. In general, plain and straightforward construction...

  2. The pinning effect in quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Monisha, P. J., E-mail: pjmonisha@gmail.com [School of Physics, University of Hyderabad, Hyderabad-500046 (India); Mukhopadhyay, Soma [Department of Physics, D V R College of Engineering and Technology, Hyderabad-502285 (India)

    2014-04-24

    The pinning effect is studied in a Gaussian quantum dot using the improved Wigner-Brillouin perturbation theory (IWBPT) in the presence of electron-phonon interaction. The electron ground state plus one phonon state is degenerate with the electron in the first excited state. The electron-phonon interaction lifts the degeneracy and the first excited states get pinned to the ground state plus one phonon state as we increase the confinement frequency.

  3. Study on contact pressure at pin connection detail; Pin setsugobu no sesshokuatsu ni taisuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Miki, C.; Anami, K. [Tokyo Institute of Technology, Tokyo (Japan); Suzuki, M. [Ministry of Construction, Tokyo (Japan); Ohashi, H. [Honshu-Shikoku Bridge Authority, Tokyo (Japan)

    1997-07-21

    Contact pressure between pin and pin plate is discussed by FEM and UT from the point of view of the connection detail of hanger lope of long span suspension bridge. Application of the UT to the 25S surface specimen (and smoother surface) is effective. The results of UT and FEM distribution of contact pressure near the center of plate almost agree with the Hertz law. However near the surface of pin plate the contact pressure and plate width of large contact pressure region increase larger than those near contact pressure and plate width of large contact pressure region increase larger than those near center of pin plate. 12 refs., 17 figs.

  4. Hegel y el fin del arte

    Directory of Open Access Journals (Sweden)

    Óscar Cubo Ugarte

    2010-03-01

    Full Text Available Uno de los puntos de mayor interés del pensamiento estético de Hegel procede de sus Lecciones de estética, y es aquel que afirma y tematiza el fin del arte. Para entender el sentido y el alcance de esta idea, presentamos en este trabajo el modo como Hegel trata el problema del arte dentro de su filosofía especulativa y en especial en sus Lecciones de Estética. Por medio de este proceso de contextualización rastreamos finalmente las distintas interpretaciones que se han producido en nuestros días acerca de la provocativa tesis del fin del arte y dejamos planteada también la cuestión del lugar que ocupa o puede ocupar el arte después del mencionado fin del arte.

  5. Hegel y el fin del arte

    Directory of Open Access Journals (Sweden)

    Óscar Cubo Ugarte

    2010-03-01

    Full Text Available Uno de los puntos de mayor interés del pensamiento estético de Hegel procede de sus Lecciones de estética, y es aquel que afirma y tematiza el fin del arte. Para entender el sentido y el alcance de esta idea, presentamos en este trabajo el modo como Hegel trata el problema del arte dentro de su filosofía especulativa y en especial en sus Lecciones de Estética. Por medio de este proceso de contextualización rastreamos finalmente las distintas interpretaciones que se han producido en nuestros días acerca de la provocativa tesis del fin del arte y dejamos planteada también la cuestión del lugar que ocupa o puede ocupar el arte después del mencionado fin del arte.

  6. Improved pinning by multiple in-line damage

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Roy [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Sawh, Ravi-Persad [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Gandini, Alberto [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Parks, Drew [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States)

    2005-02-01

    Columnar pinning centres provide the largest pinning potential, U{sub pin}, but not the greatest J{sub c} or pinnable field, B{sub pin}. Characteristics of ion-generated columnar defects which limit J{sub c} and B{sub pin} are discussed, including reduction of the percolation path, and the need for a larger number of columns of damage, for pinning, than are usually estimated. It is concluded that columnar pinning centres limit B{sub pin} to less than 4 T, and also severely reduce J{sub c}. The goal of maximizing U{sub pin}, via columnar centres, appears to have obscured a more rewarding approach and resulted in neglect of a large regime of ion interactions. Evidence is reviewed that multiple in-line damage (MILD), described herein, can provide orders of magnitude higher J{sub c} and B{sub pin}, despite providing lower U{sub pin}. The MILD pinning centre morphology is discussed, and it is estimated that for present-day large grain high T{sub c} superconductors, a J{sub c} value of {approx}10{sup 6}Acm{sup -2} is obtainable at 77 K, even when crystal plane alignment and weak links are not improved. In addition, the pinned field is increased by over an order of magnitude. An experiment is proposed to confirm these calculations, directly compare MILD pinning to continuous columnar pinning, and determine the optimum MILD structure. Applications of MILD pinning are discussed.

  7. Heat Transfer Analysis of Fin Tube

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Woo-Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Choi, Cheng-Ryul [ELSOLTEC Co., Yongin (Korea, Republic of)

    2015-10-15

    This paper describes a preliminary numerical analysis of fin tube used for a heat exchanger of the air-water cooling system. The internal flow in a fin tube is steam and the external of the fin is cooled by air. Cooling system in a nuclear power plant can be divided into two categories; 1) active pump driven system powered by alternating current and 2) passive cooling system drived by natural circulation phenomena. After the accident in Hukushima Nuclear Power Plants, the importance of the passive cooling system that can provide a long-term cooling of reactor decay heat during station blackout condition is emphasized. However, the effectiveness of passive cooling system based on cooling water is limited by the capacity of water storage tank. To overcome the limit due to the exhaustion of the cooling water, an natural convection air cooling system is proposed. As the air operated cooling system utilizes natural circulation phenomena of air, it does not require cooling water. However, the heat transfer area of the air operated cooling system should be increased much as the heat removal capacity per unit area is much lower than that of water cooling system. The air-water combined cooling system can resolve this excess increase of the heat transfer area in the air operated cooling system. This air-water cooling system can be also used in the passive containment cooling system. The effect of design parameters such as fin tube arrangement, the fin height, and pitch has been analyzed and the chimney effect on the simulation of heat transfer in a heat exchanger is evaluated. The internal flows in a fin tube heat exchanger for natural circulation flow condition and forced convection (suction) condition were investigated.

  8. MOVING SCREW DISLOCATION IN CUBIC QUASICRYSTAL

    Institute of Scientific and Technical Information of China (English)

    ZHOU Wang-min; SONG Yu-hai

    2005-01-01

    The elasticity theory of the dislocation of cubic quasicrystals is developed.The governing equations of anti-plane elasticity dynamics problem of the quasicrystals were reduced to a solution of wave equations by introducing displacement functions,and the analytical expressions of displacements, stresses and energies induced by a moving screw dislocation in the cubic quasicrystalline and the velocity limit of the dislocation were obtained. These provide important information for studying the plastic deformation of the new solid material.

  9. 2-rational Cubic Spline Involving Tension Parameters

    Indian Academy of Sciences (India)

    M Shrivastava; J Joseph

    2000-08-01

    In the present paper, 1-piecewise rational cubic spline function involving tension parameters is considered which produces a monotonic interpolant to a given monotonic data set. It is observed that under certain conditions the interpolant preserves the convexity property of the data set. The existence and uniqueness of a 2-rational cubic spline interpolant are established. The error analysis of the spline interpolant is also given.

  10. Semisymmetric Cubic Graphs of Order 162

    Indian Academy of Sciences (India)

    Mehdi Alaeiyan; Hamid A Tavallaee; B N Onagh

    2010-02-01

    An undirected graph without isolated vertices is said to be semisymmetric if its full automorphism group acts transitively on its edge set but not on its vertex set. In this paper, we inquire the existence of connected semisymmetric cubic graphs of order 162. It is shown that for every odd prime , there exists a semisymmetric cubic graph of order 162 and its structure is explicitly specified by giving the corresponding voltage rules generating the covering projections.

  11. Cubical version of combinatorial differential forms

    DEFF Research Database (Denmark)

    Kock, Anders

    2010-01-01

    The theory of combinatorial differential forms is usually presented in simplicial terms. We present here a cubical version; it depends on the possibility of forming affine combinations of mutual neighbour points in a manifold, in the context of synthetic differential geometry.......The theory of combinatorial differential forms is usually presented in simplicial terms. We present here a cubical version; it depends on the possibility of forming affine combinations of mutual neighbour points in a manifold, in the context of synthetic differential geometry....

  12. Cooling Performance of an Impingement Cooling Device Combined with Pins

    Institute of Scientific and Technical Information of China (English)

    Dongliang QUAN; Songling LIU; Jianghai LI; Gaowen LIU

    2005-01-01

    Experimental study and one dimensional model analysis were conducted to investigate cooling performance of an integrated impingement and pin fin cooling device. A typical configuration specimen was made and tested in a large scale low speed closed-looped wind tunnel. Detailed two-dimensional contour maps of the temperature and cooling effectiveness were obtained for different pressure ratios and therefore different coolant flow-rates through the tested specimen. The experimental results showed that very high cooling effectiveness can be achieved by this cooling device with relatively small amount of coolant flow. Based on the theory of transpiration cooling in porous material, a one dimensional heat transfer model was established to analyze the effect of various parameters on cooling effectiveness. It was found from this model that the variation of heat transfer on the gas side, including heat transfer coefficient and film cooling effectiveness, of the specimen created much more effect on its cooling effectiveness than that of the coolant side. The predictions of the one-dimensional mode were compared and agreed well with the experimental data.

  13. Numerical Analysis of Mixed Convection through an Internally Finned Tube

    Directory of Open Access Journals (Sweden)

    Sachindra Kumar Rout

    2012-01-01

    Full Text Available Wall temperature of an internally finned tube has been computed numerically for different fin number, height, and shape by solving conservation equations of mass, momentum, and energy using Fluent 12.1 for a steady and laminar flow of fluid inside a tube under mixed flow condition. It has been found that there exists an optimum number for fins to keep the pipe wall temperature at a minimum. The fin height has an optimum value beyond which the wall temperature becomes insensitive to fin height. For a horizontal tube, under mixed flow condition, it is seen that the upper surface has higher average temperature than the lower surface. The impact of fin shape on the heat transfer rate shows that wall temperature is least for triangular-shaped fins, compared to rectangular- and T-shaped fins. In addition to the thermal characteristics, the pressure drop caused due to the presence of fins has also been studied.

  14. Morphological Considerations of Fish Fin Shape on Thrust Generation

    Directory of Open Access Journals (Sweden)

    Kenji Kikuchi

    2014-01-01

    Full Text Available In this study, we aimed to determine the relationship between thrust generation and fish fin shape. To compare the effect fin shape had on thrust generation, we categorized the morphological shapes of fish fins into equilateral polygonal shapes. Polygonal fins were used to generate thrust that depended only on shape. These fins were constructed of a hard elastic material to eliminate any influence of shape deformation. A servomotor with a reciprocal rotation moved a fin cyclically, and thrust was experimentally measured using a strain gage system. Thrust tended to be proportional to the inertia moment of a fin, which indicated difficulty with rotation. Moreover, this trend for thrust generation was directly related to the number of apexes of a polygonal fin. The force translated ratio, which was thrust divided by the force required for fin rotation, was evaluated to determine the hydrodynamic characteristics of fins. This finding showed that the force translated ratio of a fin increased with increased movable perimeter length. The greatest thrust was generated by a triangular fin rotated at its apex, which is often seen in general fish tail fins, whereas the hydrodynamic characteristics were the worst in polygonal fins.

  15. Fin formation model during pre-roll ploughing of copper 3D outside fin tube

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The mechanism of pre-roll ploughing for 3D fins on the outside surface of copper tube was studied systematically, and especially the process and conditions of 3D fin formation were analyzed. The right mathematical model was also established. Based on the volume of fin ploughed out is equal to the volume of the metal extruded up by the extruding face of the tool, the relations between fin height, pre-roll ploughing feed and pre-roll ploughing depth have been achieved. With the increase of pre-roll ploughing depth which must be equal to groove depth, the fin height gradually becomes larger. There are different critical feeds with the various depths of pre-roll ploughing. The pre-roll ploughing feed is the critical one, the height of fin is largest. And when the feed is above the critical one, the fin height will reduce with the increase of feed. The theoretical analysis basically accords with experimental results.

  16. Propulsive performance of an under-actuated robotic ribbon fin.

    Science.gov (United States)

    Liu, Hanlin; Curet, Oscar M

    2017-06-02

    Many aquatic animals propelled by elongated undulatory fins can perform complex maneuvers and swim with high efficiency at low speeds. In this propulsion, one or multiple waves travel along an elastic fin composed of flexible rays. In this study, we explore the potential benefits or disadvantages of passive fin motion based on the coupling of fluid-structure interactions and elasto-mechanical responses of the undulatory fin. The motivation is to understand how an under-actuated undulating fin can modify its active and passive fin motion to effectively control the hydrodynamic force and propulsive efficiency. We study the kinematics and propulsive performance of an under-actuated ribbon fin using a robotic device. During two experimental sets for fully-actuated fin and under-actuated fin respectively, we measured fin kinematics, surge forces and power consumption. Our results show that under-actuated fin can generate smaller thrust but consume less power comparing to a fully-actuated counterpart. The thrust generated by an under-actuated fin scales similarly to a fully-actuated fin-linear with the enclosed area and quadratic with the relative velocity. Power consumption scales with cube of lateral tangential velocity. Furthermore, we find that the under-actuated fin can keep the same propulsive efficiency as the fully-actuated fin at low relative velocities. This finding has profound implications to both natural swimmers and underwater vehicles using undulating fin-based propulsion, as it suggests that they can potentially exploit passive fin motion without decrementing propulsive efficiency. For underwater vehicles with undulatory fins, an under-actuated design can greatly simplify the mechanical design and control complexity of a versatile propulsion system.

  17. Fin width and height dependence of bipolar amplification in bulk FinFETs submitted to heavy ion irradiation

    Institute of Scientific and Technical Information of China (English)

    于俊庭; 陈书明; 陈建军; 黄鹏程

    2015-01-01

    FinFET technologies are becoming the mainstream process as technology scales down. Based on a 28-nm bulk p-FinFET device, we have investigated the fin width and height dependence of bipolar amplification for heavy-ion-irradiated FinFETs by 3D TCAD numerical simulation. Simulation results show that due to a well bipolar conduction mechanism rather than a channel (fin) conduction path, the transistors with narrower fins exhibit a diminished bipolar amplification effect, while the fin height presents a trivial effect on the bipolar amplification and charge collection. The results also indicate that the single event transient (SET) pulse width can be mitigated about 35%at least by optimizing the ratio of fin width and height, which can provide guidance for radiation-hardened applications in bulk FinFET technology.

  18. Investigation of negative bias temperature instability dependence on fin width of silicon-on-insulator-fin-based field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Young, Chadwin D., E-mail: chadwin.young@utdallas.edu; Wang, Zhe [Materials Science and Engineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080 (United States); Neugroschel, Arnost [Department of Electrical and Computer Enginering, University of Florida, Gainesville, Florida 32611 (United States); Majumdar, Kausik; Matthews, Ken; Hobbs, Chris [SEMATECH, Albany, New York 12203 (United States)

    2015-01-21

    The fin width dependence of negative bias temperature instability (NBTI) of double-gate, fin-based p-type Field Effect Transistors (FinFETs) fabricated on silicon-on-insulator (SOI) wafers was investigated. The NBTI degradation increased as the fin width narrowed. To investigate this phenomenon, simulations of pre-stress conditions were employed to determine any differences in gate oxide field, fin band bending, and electric field profile as a function of the fin width. The simulation results were similar at a given gate stress bias, regardless of the fin width, although the threshold voltage was found to increase with decreasing fin width. Thus, the NBTI fin width dependence could not be explained from the pre-stress conditions. Different physics-based degradation models were evaluated using specific fin-based device structures with different biasing schemes to ascertain an appropriate model that best explains the measured NBTI dependence. A plausible cause is an accumulation of electrons that tunnel from the gate during stress into the floating SOI fin body. As the fin narrows, the sidewall device channel moves in closer proximity to the stored electrons, thereby inducing more band bending at the fin/dielectric interface, resulting in a higher electric field and hole concentration in this region during stress, which leads to more degradation. The data obtained in this work provide direct experimental proof of the effect of electron accumulation on the threshold voltage stability in FinFETs.

  19. Silicon LEDs in FinFET technology

    NARCIS (Netherlands)

    Piccolo, G.; Kuindersma, P.I.; Ragnarsson, L-A.; Hueting, R.J.E.; Collaert, N.; Schmitz, J.

    2014-01-01

    We present what to our best knowledge is the first forward operating silicon light-emitting diode (LED) in fin-FET technology. The results show near-infrared (NIR) emission around 1100 nm caused by band-to-band light emission in the silicon which is uniformly distributed across the lowly doped activ

  20. Design of a terahertz CW photomixer based on PIN and superlattice PIN devices

    DEFF Research Database (Denmark)

    Krozer, Viktor; Eichhorn, Finn

    2006-01-01

    We present the design of a photomixer LO based on standard and superlattice PIN diodes, operating at 1 THz. The design is based on a direct integration of a double slot antenna with the PIN device and a suitable matching circuit. The antenna has been designed together with a dielectric lens using...

  1. Dynamics and Stability of Pinned-Clamped and Clamped-Pinned Cylindrical Shells Conveying Fluid

    Science.gov (United States)

    Misra, A. K.; Wong, S. S. T.; Païdoussis, M. P.

    2001-11-01

    The paper examines the dynamics and stability of fluid-conveying cylindrical shells having pinned-clamped or clamped-pinned boundary conditions, where ``pinned'' is an abbreviation for ``simply supported''. Flügge's equations are used to describe the shell motion, while the fluid-dynamic perturbation pressure is obtained utilizing the linearized potential flow theory. The solution is obtained using two methods - the travelling wave method and the Fourier-transform approach. The results obtained by both methods suggest that the negative damping of the clamped-pinned systems and positive damping of the pinned-clamped systems, observed by previous investigators for any arbitrarily small flow velocity, are simply numerical artefacts; this is reinforced by energy considerations, in which the work done by the fluid on the shell is shown to be zero. Hence, it is concluded that both systems are conservative.

  2. Room to high temperature measurements of flexible SOI FinFETs with sub-20-nm fins

    KAUST Repository

    Diab, Amer El Hajj

    2014-12-01

    We report the temperature dependence of the core electrical parameters and transport characteristics of a flexible version of fin field-effect transistor (FinFET) on silicon-on-insulator (SOI) with sub-20-nm wide fins and high-k/metal gate-stacks. For the first time, we characterize them from room to high temperature (150 °C) to show the impact of temperature variation on drain current, gate leakage current, and transconductance. Variation of extracted parameters, such as low-field mobility, subthreshold swing, threshold voltage, and ON-OFF current characteristics, is reported too. Direct comparison is made to a rigid version of the SOI FinFETs. The mobility degradation with temperature is mainly caused by phonon scattering mechanism. The overall excellent devices performance at high temperature after release is outlined proving the suitability of truly high-performance flexible inorganic electronics with such advanced architecture.

  3. Potential of pin-by-pin SPN calculations as an industrial reference

    Energy Technology Data Exchange (ETDEWEB)

    Fliscounakis, M.; Girardi, E.; Courau, T.; Couyras, D. [EDF R and D/Sinetics, 1 av du General de Gaulle, F92141 Clamart Cedex (France)

    2012-07-01

    This paper aims at analysing the potential of pin-by-pin SP{sub n} calculations to compute the neutronic flux in PWR cores as an alternative to the diffusion approximation. As far as pin-by-pin calculations are concerned, a SPH equivalence is used to preserve the reactions rates. The use of SPH equivalence is a common practice in core diffusion calculations. In this paper, a methodology to generalize the equivalence procedure in the SP{sub n} equations context is presented. In order to verify and validate the equivalence procedure, SP{sub n} calculations are compared to 2D transport reference results obtained with the APOLL02 code. The validation cases consist in 3x3 analytical assembly color sets involving burn-up heterogeneities, UOX/MOX interfaces, and control rods. Considering various energy discretizations (up to 26 groups) and flux development orders (up to 7) for the SP{sub n} equations, results show that 26-group SP{sub 3} calculations are very close to the transport reference (with pin production rates discrepancies < 1%). This proves the high interest of pin-by-pin SP{sub n} calculations as an industrial reference when relying on 26 energy groups combined with SP{sub 3} flux development order. Additionally, the SP{sub n} results are compared to diffusion pin-by-pin calculations, in order to evaluate the potential benefit of using a SP{sub n} solver as an alternative to diffusion. Discrepancies on pin-production rates are less than 1.6% for 6-group SP{sub 3} calculations against 3.2% for 2-group diffusion calculations. This shows that SP{sub n} solvers may be considered as an alternative to multigroup diffusion. (authors)

  4. A double tuned rail damper—increased damping at the two first pinned-pinned frequencies

    Science.gov (United States)

    Maes, J.; Sol, H.

    2003-10-01

    Railway-induced vibrations are a growing matter of environmental concern. The rapid development of transportation, the increase of vehicle speeds and vehicle weights have resulted in higher vibration levels. In the meantime vibrations that were tolerated in the past are now considered to be a nuisance. Numerous solutions have been proposed to remedy these problems. The majority only acts on a specific part of the dynamic behaviour of the track. This paper presents a possible solution to reduce the noise generated by the 'pinned-pinned' frequencies. Pinned-pinned frequencies correspond with standing waves whose nodes are positioned exactly at the sleeper supports. The two first pinned-pinned frequencies are situated approximately at 950 and 2200 Hz (UIC60-rail and sleeper spacing of 0.60 m). To attenuate these vibrations, the Department of MEMC at the VUB has developed a dynamic vibration absorber called the Double Tuned Rail Damper (DTRD). The DTRD is mounted between two sleepers on the rail and is powered by the motion of the rail. The DTRD consists of two major parts: a steel plate which is connected to the rail with an interface of an elastic layer, and a rubber mass. The two first resonance frequencies of the steel plate coincide with the targeted pinned-pinned frequencies of the rail. The rubber mass acts as a motion controller and energy absorber. Measurements at a test track of the French railway company (SNCF) have shown considerable attenuation of the envisaged pinned-pinned frequencies. The attenuation rate surpasses 5 dB/m at certain frequency bands.

  5. Statistics of dislocation pinning at localized obstacles

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, A. [S. N. Bose National Centre for Basic Sciences, Salt Lake, Kolkata 700098 (India); Bhattacharya, M., E-mail: mishreyee@vecc.gov.in; Barat, P. [Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064 (India)

    2014-10-14

    Pinning of dislocations at nanosized obstacles like precipitates, voids, and bubbles is a crucial mechanism in the context of phenomena like hardening and creep. The interaction between such an obstacle and a dislocation is often studied at fundamental level by means of analytical tools, atomistic simulations, and finite element methods. Nevertheless, the information extracted from such studies cannot be utilized to its maximum extent on account of insufficient information about the underlying statistics of this process comprising a large number of dislocations and obstacles in a system. Here, we propose a new statistical approach, where the statistics of pinning of dislocations by idealized spherical obstacles is explored by taking into account the generalized size-distribution of the obstacles along with the dislocation density within a three-dimensional framework. Starting with a minimal set of material parameters, the framework employs the method of geometrical statistics with a few simple assumptions compatible with the real physical scenario. The application of this approach, in combination with the knowledge of fundamental dislocation-obstacle interactions, has successfully been demonstrated for dislocation pinning at nanovoids in neutron irradiated type 316-stainless steel in regard to the non-conservative motion of dislocations. An interesting phenomenon of transition from rare pinning to multiple pinning regimes with increasing irradiation temperature is revealed.

  6. Radon measurements with a PIN photodiode

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Martin, A. [Laboratorio de Investigacion en Baja Radiactividad (LIBRA), Edificio I-D, Campus Miguel Delibes, Universidad de Valladolid, Valladolid 47011 (Spain) and Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, Valladolid 47011 (Spain)]. E-mail: alonsomm@libra.uva.es; Gutierrez-Villanueva, J.L. [Laboratorio de Investigacion en Baja Radiactividad (LIBRA), Edificio I-D, Campus Miguel Delibes, Universidad de Valladolid, Valladolid 47011 (Spain); Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, Valladolid 47011 (Spain); Munoz, J.M. [Departamento de Electricidad y Electronica, Universidad de Valladolid, Valladolid 47011 (Spain); Garcia-Talavera, M. [Laboratorio de Investigacion en Baja Radiactividad (LIBRA), Edificio I-D, Campus Miguel Delibes, Universidad de Valladolid, Valladolid 47011 (Spain); Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, Valladolid 47011 (Spain); Adamiec, G. [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, Valladolid 47011 (Spain); Iniguez, M.P. [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, Valladolid 47011 (Spain)

    2006-10-15

    Silicon photodiodes are well suited to detect alphas coming from different sources as neutron reactions or radon daughters. In this work a radon in air detecting device, using an 18x18 mm silicon PIN photodiode is studied. The ionized airborne decay products formed during radon diffusion were focused by an accelerating high voltage to the PIN surface. Several conducting rings were disposed inside a cylindrical PVC vessel in such a way that they reproduced the electric field created by a punctual charge located behind PIN position. Alpha spectra coming from the neutral and ionized species deposited on the PIN surface, dominated by {sup 218}Po and {sup 214}Po progeny peaks, were recorded for varying conditions. Those include radon concentration from a Pylon source, high voltage (thousands of volts) and PIN inverse bias voltage. Different parameters such as temperature and humidity were also registered during data acquisition. The increase in the particle collection efficiency with respect to zero electric field was compared with the corresponding to a parallel plates configuration. A discussion is made in terms of the most appropriate voltages for different radon concentrations.

  7. Interpolation by two-dimensional cubic convolution

    Science.gov (United States)

    Shi, Jiazheng; Reichenbach, Stephen E.

    2003-08-01

    This paper presents results of image interpolation with an improved method for two-dimensional cubic convolution. Convolution with a piecewise cubic is one of the most popular methods for image reconstruction, but the traditional approach uses a separable two-dimensional convolution kernel that is based on a one-dimensional derivation. The traditional, separable method is sub-optimal for the usual case of non-separable images. The improved method in this paper implements the most general non-separable, two-dimensional, piecewise-cubic interpolator with constraints for symmetry, continuity, and smoothness. The improved method of two-dimensional cubic convolution has three parameters that can be tuned to yield maximal fidelity for specific scene ensembles characterized by autocorrelation or power-spectrum. This paper illustrates examples for several scene models (a circular disk of parametric size, a square pulse with parametric rotation, and a Markov random field with parametric spatial detail) and actual images -- presenting the optimal parameters and the resulting fidelity for each model. In these examples, improved two-dimensional cubic convolution is superior to several other popular small-kernel interpolation methods.

  8. Curvature-induced stiffening of a fish fin

    CERN Document Server

    Nguyen, Khoi; Bandi, Mahesh M; Venkadesan, Madhusudhan; Mandre, Shreyas

    2016-01-01

    Fish behaviour and its ecological niche require modulation of its fin stiffness. Using mathematical analyses of rayed fish fins, we show that curvature transverse to the rays is central to fin stiffness. We model the fin as rays with anisotropic bending that are connected by an elastic membrane. For fins with transverse curvature, external loads that bend the rays also splay them apart, which stretches the membrane. This coupling, between ray bending and membrane stretching, underlies the curvature-induced stiffness. A fin that appears flat may still exhibit bending-stretching coupling if the principal bending axes of adjacent rays are misaligned by virtue of intrinsic geometry, i.e. morphologically flat yet functionally curved. Analysis of the pectoral fin of a mackerel shows such functional curvature. Furthermore, as identified by our analyses, the mackerel's fin morphology endows it with the potential to modulate stiffness over a wide range.

  9. The effect of temperature on pinning mechanisms in HTS composites

    Science.gov (United States)

    Sotnikova, A. P.; Rudnev, I. A.

    2016-09-01

    Pinning mechanism in samples of second generation tapes (2G) of high-temperature superconductors (HTS) was studied The critical current and the pinning force were calculated from the magnetization curves measured in the temperature range of 4.2 - 77 K in magnetic fields up to 14 Tesla using vibration sample magnetometer. To determine the pinning mechanism the dependences of pinning force on magnetic field were constructed according to the Dew-Hughes model and Kramer's rule. The obtained dependences revealed a significant influence of the temperature on effectiveness of different types of pinning. At low temperatures the 2G HTS tapes of different manufacturers demonstrated an equal efficiency of the pinning centers but with temperature increase the differences in pinning mechanisms as well as in properties and effectiveness of the pinning centers become obvious. The influence of the pinning mechanism on the energy losses in HTS tapes was shown.

  10. Embryonic development of fin spines in Callorhinchus milii (Holocephali); implications for chondrichthyan fin spine evolution.

    Science.gov (United States)

    Jerve, Anna; Johanson, Zerina; Ahlberg, Per; Boisvert, Catherine

    2014-01-01

    Fin spines are commonly known from fossil gnathostomes (jawed vertebrates) and are usually associated with paired and unpaired fins. They are less common among extant gnathostomes, being restricted to the median fins of certain chondrichthyans (cartilaginous fish), including chimaerids (elephant sharks) and neoselachians (sharks, skates, and rays). Fin spine growth is of great interest and relevance but few studies have considered their evolution and development. We investigated the development of the fin spine of the chimaerid Callorhinchus milii using stained histological sections from a series of larval, hatchling, and adult individuals. The lamellar trunk dentine of the Callorhinchus spine first condenses within the mesenchyme, rather than at the contact surface between mesenchyme and epithelium, in a manner more comparable to dermal bone formation than to normal odontode development. Trabecular dentine forms a small component of the spine under the keel; it is covered externally with a thin layer of lamellar trunk dentine, which is difficult to distinguish in sectioned adult spines. We suggest that the distinctive characteristics of the trunk dentine may reflect an origin through co-option of developmental processes involved in dermal bone formation. Comparison with extant Squalus and a range of fossil chondrichthyans shows that Callorhinchus is more representative than Squalus of generalized chondrichthyan fin-spine architecture, highlighting its value as a developmental model organism. © 2014 Wiley Periodicals, Inc.

  11. CFD Analysis of Plate Fin Tube Heat Exchanger for Various Fin Inclinations

    Directory of Open Access Journals (Sweden)

    Subodh Bahirat,

    2014-08-01

    Full Text Available ANSYS Fluent software is used for three dimensional CFD simulations to investigate heat transfer and fluid flow characteristics of six different fin angles with plain fin tube heat exchangers. The numerical simulation of the fin tube heat exchanger was performed by using a three dimensional numerical computation technique. Geometry of model is created and meshed by using ANSYS Workbench software. To solve the equation for the fluid flow and heat transfer analysis ANSYS FLUENT was used in the fin-tube heat exchanger. The fluid flow and heat transfer are simulated and result compared for both laminar and turbulent flow models k-epsilon and SST k-omega, with steady state solvers to calculate heat transfer, flow velocity and temperature fields of variable inclined fin angles (Ɵ = 00 ,100 , 200 , 300 , 400 ,500 . Model is validate by comparing the simulated value of velocity, temperature and colburn factor with experimental and numerical results investigated by WANG [1] and GHORI KIRAR [10]. Reasonable agreement is found between the simulations and other results, and the ANSYS Fluent software is sufficient for simulating the flow fields in tube fin heat exchanger.

  12. Film condensation of steam on externally finned horizontal tubes.

    OpenAIRE

    Flook, Frederick A.

    1985-01-01

    Approved for public release; distribution is unlimited Filmwise condensation measurements of steam were made on horizontal finned tubes under vacuum and near-atmospheric conditions. Data were obtained for copper tubes with fins of rectangular, triangular, trapezoidal, and parabolic cross sections, and for a commercially-available finned tube. A stainless steel finned tube was also tested to investigate the effect of thermal conductivity. Maximum enhancements of about 4.8 were obtained...

  13. Heat transfer in bundles of finned tubes in crossflow

    Energy Technology Data Exchange (ETDEWEB)

    Stasiulevicius, J.; Skrinska, A.; Zukauskas, A.; Hewitt, G.F.

    1986-01-01

    This book provides correlations of heat transfer and hydraulic data for bundles of finned tubes in crossflow at high Reynolds numbers. Results of studies of the effectiveness of the fin, local, and mean heat transfer coefficients are presented. The effect of geometric parameters of the fins and of the location of tubes in the bundle on heat transfer and hydraulic drag are described. The resistance of the finned tube bundles under study and other factors are examined.

  14. THERMAL EFFICIENCY ANALYSIS OF CROSS-FINNED TUBES

    OpenAIRE

    Лагутін, А.Ю.; П.Ф. Стоянов

    2015-01-01

    Finned heat exchangers are the basic type of heat exchanger employed in many industrial applications such as refrigeration, air conditioning and other thermal processes. This paper presents experimental research of air-side heat transfer of finned surfaces. Seven types of finned surfaces are employed in this study. Investigation describes temperature fields and temperature cooling air-flow changing in the inter-fin duct without taking into account tube section. Temperature difference in-betwe...

  15. Curvature-induced stiffening of a fish fin

    OpenAIRE

    Nguyen, Khoi; Yu, Ning; Bandi, Mahesh M.; Venkadesan, Madhusudhan; Mandre, Shreyas

    2016-01-01

    How fish modulate their fin stiffness during locomotive manoeuvres remains unknown. We show that changing the fin's curvature modulates its stiffness. Modelling the fin as bendable bony rays held together by a membrane, we deduce that fin curvature is manifested as a misalignment of the principal bending axes between neighbouring rays. An external force causes neighbouring rays to bend and splay apart, and thus stretches the membrane. This coupling between bending the rays and stretching the ...

  16. Termination of pinned spirals by local stimuli

    Science.gov (United States)

    Chen, Jiang-Xing; Guo, Ming-Ming; Ma, Jun

    2016-02-01

    The termination of pinned spirals on a defect by means of local stimuli is studied. On a completely unexcitable defect, the elimination process is discussed and its corresponding mechanism is presented. Especially, the mechanism of unpinning spirals on a partially unexcitable defect, which has not been investigated so far, is explored. With fixed pacing frequency ω L , there exists a maximal radius R max above which the pinned spiral cannot be removed. It is found that the value of R max does not increase as ω L in a dynamical regime, forming a platform in the R\\textit{max}\\text-ωL curves. Based on analyzing the dispersion relation on the spiral tip around the obstacle, the underlying mechanism is clarified. Also, it is found that when multiple spirals are pinned, the value of R max decreases on a partially unexcitable defect while the change is very slight on a completely unexcitable one.

  17. Pin solar cells made of amorphous silicon

    Science.gov (United States)

    Plaettner, R. D.; Kruehler, W. W.

    Investigations leading to solar cells with a structure SnO2-pin and an efficiency up to 9.8% are reviewed. The production of large-surface metal/pin/transparent conductive oxide (TCO)-solar cells is discussed. A two-chamber reactor, grid structure and tinning of cells, and an a-Si-module are described. The production of glass/TCO/pin/metal-solar cells and a-SiGe:H-compounds is outlined. Measurements on solar cells and diodes including the efficiency of a-Si:H-solar cells, spectral sensitivity, diffusion lengths, field effect measurements, and modifications of solar cells (space-charge limited currents, reduction of solar cells aging) are treated.

  18. Superhard BC(3) in cubic diamond structure.

    Science.gov (United States)

    Zhang, Miao; Liu, Hanyu; Li, Quan; Gao, Bo; Wang, Yanchao; Li, Hongdong; Chen, Changfeng; Ma, Yanming

    2015-01-01

    We solve the crystal structure of recently synthesized cubic BC(3) using an unbiased swarm structure search, which identifies a highly symmetric BC(3) phase in the cubic diamond structure (d-BC(3)) that contains a distinct B-B bonding network along the body diagonals of a large 64-atom unit cell. Simulated x-ray diffraction and Raman peaks of d-BC(3) are in excellent agreement with experimental data. Calculated stress-strain relations of d-BC(3) demonstrate its intrinsic superhard nature and reveal intriguing sequential bond-breaking modes that produce superior ductility and extended elasticity, which are unique among superhard solids. The present results establish the first boron carbide in the cubic diamond structure with remarkable properties, and these new findings also provide insights for exploring other covalent solids with complex bonding configurations.

  19. Cubical Cohomology Ring of 3D Photographs

    CERN Document Server

    Gonzalez-Diaz, Rocio; Medrano, Belen; 10.1002/ima.20271

    2011-01-01

    Cohomology and cohomology ring of three-dimensional (3D) objects are topological invariants that characterize holes and their relations. Cohomology ring has been traditionally computed on simplicial complexes. Nevertheless, cubical complexes deal directly with the voxels in 3D images, no additional triangulation is necessary, facilitating efficient algorithms for the computation of topological invariants in the image context. In this paper, we present formulas to directly compute the cohomology ring of 3D cubical complexes without making use of any additional triangulation. Starting from a cubical complex $Q$ that represents a 3D binary-valued digital picture whose foreground has one connected component, we compute first the cohomological information on the boundary of the object, $\\partial Q$ by an incremental technique; then, using a face reduction algorithm, we compute it on the whole object; finally, applying the mentioned formulas, the cohomology ring is computed from such information.

  20. Effective pinning energy landscape perturbations for propagating magnetic domain walls

    Science.gov (United States)

    Burn, D. M.; Atkinson, D.

    2016-01-01

    The interaction between a magnetic domain wall and a pinning site is explored in a planar nanowire using micromagnetics to reveal perturbations of the pinning energetics for propagating domain walls. Numerical simulations in the high damping ’quasi-static’ and low damping ’dynamic’ regimes are compared and show clear differences in de-pinning fields, indicating that dynamical micromagnetic models, which incorporate precessionally limited magnetization processes, are needed to understand domain wall pinning. Differences in the micromagnetic domain wall structure strongly influence the pinning and show periodic behaviour with increasing applied field associated with Walker breakdown. In the propagating regime pinning is complicated. PMID:27694953

  1. Broken safety pin in bronchus - Anaesthetic considerations

    Directory of Open Access Journals (Sweden)

    Roona Shad

    2012-01-01

    Full Text Available Safety pins are not commonly aspirated objects in infants and form only a small fraction of all the metallic foreign body (FB which accounts for 4.4% of all foreign bodies found in tracheobronchial tree. Bronchoscopy procedure has various complications, in addition to failure to remove FB due to its impaction, especially with metallic pointed objects ending up in open surgical removal. Infant with inhaled foreign body are always a challenge to anaesthetist. We had one such case of broken safety pin impacted in the wall of right bronchus of an infant with failure to remove on repeated attempts at rigid bronchoscopy.

  2. Broken safety pin in bronchus - Anaesthetic considerations.

    Science.gov (United States)

    Shad, Roona; Agarwal, Aditya

    2012-11-01

    Safety pins are not commonly aspirated objects in infants and form only a small fraction of all the metallic foreign body (FB) which accounts for 4.4% of all foreign bodies found in tracheobronchial tree. Bronchoscopy procedure has various complications, in addition to failure to remove FB due to its impaction, especially with metallic pointed objects ending up in open surgical removal. Infant with inhaled foreign body are always a challenge to anaesthetist. We had one such case of broken safety pin impacted in the wall of right bronchus of an infant with failure to remove on repeated attempts at rigid bronchoscopy.

  3. Self-Pinning on a Liquid Surface.

    Science.gov (United States)

    Antoine, C; Irvoas, J; Schwarzenberger, K; Eckert, K; Wodlei, F; Pimienta, V

    2016-02-04

    We report on the first experimental evidence of a self-pinning liquid drop on a liquid surface. This particular regime is observed for a miscible heavier oil drop (dichloromethane) deposited on an aqueous solution laden by an ionic surfactant (hexadecyltrimethylammonium bromide). Experimental characterization of the drop shape evolution coupled to particle image velocimetry points to the correlation between the drop profile and the accompanying flow field. A simple model shows that the observed pinned stage is the result of a subtle competition between oil dissolution and surfactant adsorption.

  4. Purely cubic action for string field theory

    Science.gov (United States)

    Horowitz, G. T.; Lykken, J.; Rohm, R.; Strominger, A.

    1986-01-01

    It is shown that Witten's (1986) open-bosonic-string field-theory action and a closed-string analog can be written as a purely cubic interaction term. The conventional form of the action arises by expansion around particular solutions of the classical equations of motion. The explicit background dependence of the conventional action via the Becchi-Rouet-Stora-Tyutin operator is eliminated in the cubic formulation. A closed-form expression is found for the full nonlinear gauge-transformation law.

  5. Purely cubic action for string field theory

    Science.gov (United States)

    Horowitz, G. T.; Lykken, J.; Rohm, R.; Strominger, A.

    1986-01-01

    It is shown that Witten's (1986) open-bosonic-string field-theory action and a closed-string analog can be written as a purely cubic interaction term. The conventional form of the action arises by expansion around particular solutions of the classical equations of motion. The explicit background dependence of the conventional action via the Becchi-Rouet-Stora-Tyutin operator is eliminated in the cubic formulation. A closed-form expression is found for the full nonlinear gauge-transformation law.

  6. New types of high field pinning centers and pinning centers for the peak effect

    Science.gov (United States)

    Gajda, Daniel; Zaleski, Andrzej; Morawski, Andrzej; Hossain, Md Shahriar A.

    2017-08-01

    In this article, we report the results of a study that shows the existence of pinning centers inside grains and between grains in NbTi wires. We accurately show the ranges of magnetic fields in which the individual pinning centers operate. The pinning centers inside grains are activated in high magnetic fields above 6 T. We show the range of magnetic fields in which individual defects, dislocations, precipitates inside grains and substitutions in the crystal lattice can operate. We show the existence of a new kind of high field pinning center, which operates in high magnetic fields from 8 to ˜9.5 T. We indicate that dislocations create pinning centers in the range of magnetic fields from 6 to 8 T. In addition, our measurements suggest that the peak effect (increased critical current density (J c) near the upper critical field (B c2)) could be attributed to martensitic (needle-shaped) α‧-Ti inclusions inside grains. These centers are very important because they work very effectively in magnetic fields above 9.5-10 T. We also show that the α-Ti precipitates (between grains) with a thickness similar to the coherence length create pinning centers which work very effectively in magnetic fields from 3 to 6 T. In magnetic fields below 3 T, they act very efficiently in grain boundaries. The measurements indicate that the pinning centers created by dislocations only can be tested by transport measurements. This indicates that dislocations do not increase the magnetic critical current density (J cm). Cold drawing improves pinning centers at grain boundaries and increases the dislocation density, and cold-drawing pinning centers are responsible for the peak effect.

  7. Effect of the number of pins and inter-pin distance on somatosensory evoked magnetic fields following mechanical tactile stimulation.

    Science.gov (United States)

    Onishi, Hideaki; Sugawara, Kazuhiro; Yamashiro, Koya; Sato, Daisuke; Suzuki, Makoto; Kirimoto, Hikari; Tamaki, Hiroyuki; Murakami, Hiroatsu; Kameyama, Shigeki

    2013-10-16

    Magnetoencephalography (MEG) recordings were collected to investigate the effect of the number of mechanical pins and inter-pin distance on somatosensory evoked magnetic fields (SEFs) following mechanical stimulation (MS). We used a 306-ch whole-head MEG system. SEFs were elicited through tactile stimuli with 1-, 2-, 3-, 4- and 8-pins using healthy participants. Tactile stimuli were applied to the tip of the right index finger. SEF following electrical stimulation of the index finger was recorded in order to compare the activity in the primary somatosensory cortex (S1) following MS. Prominent SEFs were recorded from the contralateral hemisphere approximately 54 ms (P50m) and 125 ms (P100m) after MS regardless of the number of pins. Equivalent current dipoles were located in the S1. The source activities for P50m and P100m significantly increased in tandem with the number of pins for MS. However, the increased ratios for the source activities according to the increase in the number of pins were significantly smaller than that induced by electrical stimulation, and when the number of the pins doubled from 1-pin to 2-pins, from 2-pins to 4-pins, and from 4-pins to 8-pins, S1 activities increased by only 130%. Additionally, source activities significantly increased when the inter-pin distance increased from 2.4 to 7.2 mm. The number of stimulated receptors was considered to have increased with an increase in the inter-pin distance as well as an increase in the number of pins. These findings clarified the effect of the number of pins and inter-pin distance for MS on SEFs.

  8. NUMERICAL AND EXPERIMENTAL STUDIES OF INFLUENCE OF THE CAUDAL FIN SHAPE ON THE PROPULSION PERFORMANCE OF A FLAPPING CAUDAL FIN

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xi; SU Yu-min; WANG Zhao-li

    2011-01-01

    This article presents a comprehensive study of the effects of the caudal fin shape on the propulsion performance of a eandal fin in harmonic heaving and pitching.A numerical simulation based on an unsteady panel method was carried out to analyze the hydrodynamic performance of flapping caudal fins of three shapes (the whale caudal fin with the largest projected area, the dolphin caudal fin with the median projected area, and the tuna caudal fin with the smallest projected area).Then, a series of hydrodynamic experiments for three caudal fin shapes were performed.Both computational and experimental results indicate that the tuna caudal fin produces the highest efficiency.However the mean thrust coefficient of the tuna caudal fin is the smallest.It is found that although the mean thrust coefficient for the tuna caudal fin is not large, the input power of the tuna caudal fin is also quite small.So the tuna caudal fin achieves a high efficiency.

  9. An experimental investigation on the airside performance of fin-and-tube heat exchangers having slit fins under wet condition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nae Hyun [Incheon National University, Incheon (Korea, Republic of); Kim, Tae Hun [Samsung Electronics Co., Suwon (Korea, Republic of)

    2015-11-15

    In this study, the heat transfer and friction characteristics of the 5.3 mm O.D. slit-finned heat exchangers under wet condition have been experimentally investigated. Plain-finned heat exchangers having the same 5.3 mm O.D. tubes are also tested for comparison purpose. The effect of fin pitch on j and f factor is negligible. Slit fin samples yield higher j and f factors than plain fin samples. For one row configuration, the average f factor ratio between slit fin sample and plain fin sample is 2.18. The ratio increases to 2.41 for two row configuration, and to 2.65 for three row configuration. As for the j factor, the ratios are approximately the same (1.61, 1.70 and 1.71 for one, two and three row configuration). Both j and f factor increase as the number of tube row decreases. The same trend is observed for the plain fin samples. At high Reynolds numbers, the j/f ratios of the slit fin are approximately the same as those of the plain fin. At low Reynolds numbers, the j/f ratios of the slit fin are smaller than those of plain fin. Data are compared with existing correlations.

  10. Sizing-tube-fin space radiators

    Science.gov (United States)

    Peoples, J. A.

    1978-01-01

    Temperature and size considerations of the tube fin space radiator were characterized by charts and equations. An approach of accurately assessing rejection capability commensurate with a phase A/B level output is reviewed. A computer program, based on Mackey's equations, is also presented which sizes the rejection area for a given thermal load. The program also handles the flow and thermal considerations of the film coefficient.

  11. Composite hydrophilic coating for conditioner aluminum fins

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    To solve the so-called "white rust" and 'water bridge" problems of the aluminum fins for heat exchanger of automobile air conditioner, aimed at nationalizing the art of hydrophilic coating technology, the choice of coating forming and curing materials was investigated. By measuring the water contact angle, SEM surface scanning and ingredients analysis of the coating, optimal parameters and composition are acquired. The coating forming mechanisms of the composition was also expatiated. The coating obtained has good hydrophilic and other properties.

  12. Histological study of the dynamics in epidermis regeneration of the carp tail fin (Cyprinus carpio, Linnaeus, 1758).

    Science.gov (United States)

    Böckelmann, P K; Ochandio, B S; Bechara, I J

    2010-02-01

    Teleostean fins when partially amputated suffer a regenerative process called epimorphic regeneration, characterized by the following stages: healing, based on the formation of a multistratified epidermal layer, the formation of a mass of pluripotent cells known as blastema, the differentiation of these cells, the synthesis and disposition of the extracellular matrix, morphological growth and restoration. The epidermis has a fundamental role in the regenerative process of fish fins, as the healing time of this structure leads it to a faster regenerative process and it also works as a defense against the external environment. In this sense, due to the fast regeneration shown by the epidermis, the aim of this paper is to study the histology of the regenerative dynamics of the carp fin tail (Cyprinus carpio), under the light and transmission electron microscope. Epidermic regeneration begins right in the first hours after the fin amputation and it continues throughout the regenerative process. After 24 hours, an apical epidermal cap is established. Cytoplasmatic prolongations and intercellular junctions are observed and the cells of the basal layer of the epidermis change from the cubic form to the cylindrical, due to the development of the cytoplasmatic organelles responsible for the synthesis of the basal membrane, lost after amputation. These results show the importance of histological studies in regenerative processes. We believe that the association of molecular biology with histological studies can throw further light onto these regenerative dynamics.

  13. Histological study of the dynamics in epidermis regeneration of the carp tail fin (Cyprinus carpio, Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    PK. Böckelmann

    Full Text Available Teleostean fins when partially amputated suffer a regenerative process called epimorphic regeneration, characterized by the following stages: healing, based on the formation of a multistratified epidermal layer, the formation of a mass of pluripotent cells known as blastema, the differentiation of these cells, the synthesis and disposition of the extracellular matrix, morphological growth and restoration. The epidermis has a fundamental role in the regenerative process of fish fins, as the healing time of this structure leads it to a faster regenerative process and it also works as a defense against the external environment. In this sense, due to the fast regeneration shown by the epidermis, the aim of this paper is to study the histology of the regenerative dynamics of the carp fin tail (Cyprinus carpio, under the light and transmission electron microscope. Epidermic regeneration begins right in the first hours after the fin amputation and it continues throughout the regenerative process. After 24 hours, an apical epidermal cap is established. Cytoplasmatic prolongations and intercellular junctions are observed and the cells of the basal layer of the epidermis change from the cubic form to the cylindrical, due to the development of the cytoplasmatic organelles responsible for the synthesis of the basal membrane, lost after amputation. These results show the importance of histological studies in regenerative processes. We believe that the association of molecular biology with histological studies can throw further light onto these regenerative dynamics.

  14. Study on Thermo-Conductive Plastic Finned Tube Radiators

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    This paper discusses thermo-conductive plastic finned tube radiators used in water saving type power stations.First,the development of thermo-conductive plastics is introduced.Second,in order to determine the rational geometric dimensions of thermo-conductive plastic finned tubes,an objective function which takes the minimum volume of the consumed material for making finned tubes as an object is introduced.On the basis of the function,the economy comparison between thermo-conductive plastic finned tubes and metal finned tubes is conducted.

  15. Performance Prediction of Cross-Finned Tube Heat Exchangers

    Science.gov (United States)

    Kondou, Chieko; Senshu, Takao; Oguni, Kensaku

    The plane fin of a cross-finned tube heat exchangers is the basis for all kinds of fins used in air conditioners. In this paper, an improvement the dimensionless arrangements of pressure drop for plane fins was attempted. The detailed calculation results for all geometrical parameters, especially tube disposition, showed the reflecting to the effect of contracted flow in the existing equations of friction factor is insufficient. Therefore, an amendment for these equations was suggested. Further, the analogy between the revised friction factor and the Colburn's j factor was verified. In addition an approximate expression for the fin efficiency using wide parameters was devised.

  16. Asymmetrically doped stacked channel strained SOI FinFET

    Science.gov (United States)

    Dubey, Shashank; Kondekar, Pravin N.

    2017-02-01

    Strained SOI (SSOI) n-channel trigate FinFET is designed with asymmetrically doped stacked channels along the fin height. The OFF current is reduced with respect to lightly doped uniform SSOI FinFET because of band gap modification, originated between highly doped uniaxial strained and lightly doped Si fin. Through TCAD simulation it is observed that for the stacked devices the OFF current is reduced by more than 47%. The performances are also compared with highly doped uniform SSOI FinFETs and the results indicated that these devices have lesser random dopant variation at a moderate cost of ON and OFF current.

  17. A pinned polymer model of posture control

    CERN Document Server

    Chow, C C; Chow, Carson C; Collins, J J

    1995-01-01

    A phenomenological model of human posture control is posited. The dynamics are modelled as an elastically pinned polymer under the influence of noise. The model accurately reproduces the two-point correlation functions of experimental posture data and makes predictions for the response function of the postural control system. The physiological and clinical significance of the model is discussed.

  18. Duodenocolic fistula due to safety pin ingestion.

    Science.gov (United States)

    Cay, Ali; Imamoğlu, Mustafa; Sarihan, Haluk; Sayil, Ozgür

    2004-01-01

    The authors describe the case of a 16-month-old boy with benign duodenocolic fistula due to safety pin ingestion who presented with abdominal pain, diarrhea and weight loss. Etiology, symptomatology, diagnosis and management are discussed and the literature is reviewed. Early diagnosis and surgical management are necessary to avoid serious morbidity.

  19. Turban pin aspiration: new fashion, new syndrome.

    Science.gov (United States)

    Ilan, Ophir; Eliashar, Ron; Hirshoren, Nir; Hamdan, Kasem; Gross, Menachem

    2012-04-01

    Turban pin aspiration syndrome is a new clinical entity afflicting young Islamic girls wearing a turban.The goal of this study was to present our experience in diagnosis and treatment of this new entity, define its clinical and epidemiologic features, and shed a new light on the role of fashion in the increased incidence. A retrospective study in a tertiary university hospital. Review of clinical parameters and epidemiologic features of 26 patients diagnosed with turban pin aspiration syndrome admitted to the Hadassah-Hebrew University Hospitals in Jerusalem from 1990 to 2010. All patients were Muslim females with an average age of 16 years. In all cases, the history was positive for accidental aspiration. Most of the pins were located in the trachea (42%). In 20 cases, the pins were extracted by rigid bronchoscopy without major complications. Fluoroscopy-assisted rigid bronchoscopy was used successfully in three cases. In one case, the object was self-ejected by coughing before the bronchoscopy, and two patients were referred to the chest unit for thoracotomy. Clinicians should be aware of this distinct form of foreign body aspiration, its method of diagnosis, and extraction techniques. A cultural investigation showed a difference in the turban-fastening technique of young girls as compared with their mothers. Removal by rigid bronchoscopy is a safe method with a high success rate and should be considered as the preferred extraction method of choice. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

  20. DEFICIENT CUBIC SPLINES WITH AVERAGE SLOPE MATCHING

    Institute of Scientific and Technical Information of China (English)

    V. B. Das; A. Kumar

    2005-01-01

    We obtain a deficient cubic spline function which matches the functions with certain area matching over a greater mesh intervals, and also provides a greater flexibility in replacing area matching as interpolation. We also study their convergence properties to the interpolating functions.

  1. Counting rational points on cubic curves

    Institute of Scientific and Technical Information of China (English)

    HEATH-BROWN; Roger; TESTA; Damiano

    2010-01-01

    We prove upper bounds for the number of rational points on non-singular cubic curves defined over the rationals.The bounds are uniform in the curve and involve the rank of the corresponding Jacobian.The method used in the proof is a combination of the "determinant method" with an m-descent on the curve.

  2. CONSTRAINED RATIONAL CUBIC SPLINE AND ITS APPLICATION

    Institute of Scientific and Technical Information of China (English)

    Qi Duan; Huan-ling Zhang; Xiang Lai; Nan Xie; Fu-hua (Frank) Cheng

    2001-01-01

    In this paper, a kind of rational cubic interpolation functionwith linear denominator is constructed. The constrained interpolation with constraint on shape of the interpolating curves and on the second-order derivative of the interpolating function is studied by using this interpolation, and as the consequent result, the convex interpolation conditions have been derived.

  3. Anisotropy of a cubic ferromagnet at criticality

    Science.gov (United States)

    Kudlis, A.; Sokolov, A. I.

    2016-10-01

    Critical fluctuations change the effective anisotropy of cubic ferromagnet near the Curie point. If the crystal undergoes phase transition into orthorhombic phase and the initial anisotropy is not too strong, reduced anisotropy of nonlinear susceptibility acquires at Tc the universal value δ4*=2/v* 3 (u*+v*) where u* and v* are coordinates of the cubic fixed point on the flow diagram of renormalization group equations. In the paper, the critical value of the reduced anisotropy is estimated within the pseudo-ɛ expansion approach. The six-loop pseudo-ɛ expansions for u*, v*, and δ4* are derived for the arbitrary spin dimensionality n . For cubic crystals (n =3 ) higher-order coefficients of the pseudo-ɛ expansions obtained turn out to be so small that use of simple Padé approximants yields reliable numerical results. Padé resummation of the pseudo-ɛ series for u*, v*, and δ4* leads to the estimate δ4*=0.079 ±0.006 , indicating that detection of the anisotropic critical behavior of cubic ferromagnets in physical and computer experiments is certainly possible.

  4. Binomial Squares in Pure Cubic Number Fields

    CERN Document Server

    Lemmermeyer, Franz

    2011-01-01

    Let K = Q(\\omega) with \\omega^3 = m be a pure cubic number field. We show that the elements\\alpha \\in K^\\times whose squares have the form a - \\omega form a group isomorphic to the group of rational points on the elliptic curve E_m: y^2= x^3 - m.

  5. The cactus rank of cubic forms

    CERN Document Server

    Bernardi, Alessandra

    2011-01-01

    We prove that the smallest degree of an apolar 0-dimensional scheme to a general cubic form in $n+1$ variables is at most $2n+2$, when $n\\geq 8$, and therefore smaller than the rank of the form. When n=8 we show that the bound is sharp, i.e. the smallest degree of an apolar subscheme is 18.

  6. Pinning control of clustered complex networks with different size

    Science.gov (United States)

    Fu, Chenbo; Wang, Jinbao; Xiang, Yun; Wu, Zhefu; Yu, Li; Xuan, Qi

    2017-08-01

    In pinning control of complex networks, it is found that, with the same pinning effort, the network can be better controlled by pinning the large-degree nodes. But in the clustered complex networks, this preferential pinning (PP) strategy is losing its effectiveness. In this paper, we demonstrate that in the clustered complex networks, especially when the clusters have different size, the random pinning (RP) strategy performs much better than the PP strategy. Then, we propose a new pinning strategy based on cluster degree. It is revealed that the new cluster pinning strategy behaves better than RP strategy when there are only a smaller number of pinning nodes. The mechanism is studied by using eigenvalue and eigenvector analysis, and the simulations of coupled chaotic oscillators are given to verify the theoretical results. These findings could be beneficial for the design of control schemes in some practical systems.

  7. Analytical method for reconstruction pin to pin of the nuclear power density distribution

    Energy Technology Data Exchange (ETDEWEB)

    Pessoa, Paulo O.; Silva, Fernando C.; Martinez, Aquilino S., E-mail: ppessoa@con.ufrj.br, E-mail: fernando@con.ufrj.br, E-mail: aquilino@imp.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    An accurate and efficient method for reconstructing pin to pin of the nuclear power density distribution, involving the analytical solution of the diffusion equation for two-dimensional neutron energy groups in homogeneous nodes, is presented. The boundary conditions used for analytic as solution are the four currents or fluxes on the surface of the node, which are obtained by Nodal Expansion Method (known as NEM) and four fluxes at the vertices of a node calculated using the finite difference method. The analytical solution found is the homogeneous distribution of neutron flux. Detailed distributions pin to pin inside a fuel assembly are estimated by the product of homogeneous flux distribution by local heterogeneous form function. Furthermore, the form functions of flux and power are used. The results obtained with this method have a good accuracy when compared with reference values. (author)

  8. Pinning control of complex networked systems synchronization, consensus and flocking of networked systems via pinning

    CERN Document Server

    Su, Housheng

    2013-01-01

    Synchronization, consensus and flocking are ubiquitous requirements in networked systems. Pinning Control of Complex Networked Systems investigates these requirements by using the pinning control strategy, which aims to control the whole dynamical network with huge numbers of nodes by imposing controllers for only a fraction of the nodes. As the direct control of every node in a dynamical network with huge numbers of nodes might be impossible or unnecessary, it’s then very important to use the pinning control strategy for the synchronization of complex dynamical networks. The research on pinning control strategy in consensus and flocking of multi-agent systems can not only help us to better understand the mechanisms of natural collective phenomena, but also benefit applications in mobile sensor/robot networks. This book offers a valuable resource for researchers and engineers working in the fields of control theory and control engineering.   Housheng Su is an Associate Professor at the Department of Contro...

  9. Auxin transport through PIN-FORMED 3 (PIN3) controls shade avoidance and fitness during competition

    Science.gov (United States)

    Keuskamp, Diederik H.; Pollmann, Stephan; Voesenek, Laurentius A. C. J.; Peeters, Anton J. M.; Pierik, Ronald

    2010-01-01

    Plants grow in dense vegetations at the risk of being out-competed by neighbors. To increase their competitive power, plants display adaptive responses, such as rapid shoot elongation (shade avoidance) to consolidate light capture. These responses are induced upon detection of proximate neighbors through perception of the reduced ratio between red (R) and far-red (FR) light that is typical for dense vegetations. The plant hormone auxin is a central regulator of plant development and plasticity, but until now it has been unknown how auxin transport is controlled to regulate shade-avoidance responses. Here, we show that low R:FR detection changes the cellular location of the PIN-FORMED 3 (PIN3) protein, a regulator of auxin efflux, in Arabidopsis seedlings. As a result, auxin levels in the elongating hypocotyls are increased under low R:FR. Seedlings of the pin3-3 mutant lack this low R:FR-induced increase of endogenous auxin in the hypocotyl and, accordingly, have no elongation response to low R:FR. We hypothesize that low R:FR-induced stimulation of auxin biosynthesis drives the regulation of PIN3, thus allowing shade avoidance to occur. The adaptive significance of PIN3-mediated control of shade-avoidance is shown in plant competition studies. It was found that pin3 mutants are outcompeted by wild-type neighbors who suppress fitness of pin3-3 by 40%. We conclude that low R:FR modulates the auxin distribution by a change in the cellular location of PIN3, and that this control can be of great importance for plants growing in dense vegetations. PMID:21149713

  10. Optimization study on pin tip diameter of an impact-pin nozzle at high pressure ratio

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, C. Palani; Lee, Kwon Hee [FMTRC, Daejoo Machinery Co. Ltd., Daegu (Korea, Republic of); Park, Tae Choon; Cha, Bong Jun [Engine Components Research Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Kim, Heuy Dong [Dept. of Mechanical Engineering, Andong National University, Andong (Korea, Republic of)

    2016-09-15

    Wet compression system is typically installed in a gas turbine engine to increase the net power output and efficiency. A crucial component of the wet compression system is the nozzle which generates fine water droplets for injection into the compressor. The main objective of present work is to optimize a kind of nozzle called impact-pin spray nozzle and thereby produce better quality droplets. To achieve this, the dynamics occurring in the water jet impinging on the pin tip, the subsequent formation of water sheet, which finally breaks into water droplets, must be studied. In this manuscript, the progress on the numerical studies on impact-pin nozzle are reported. A small computational domain covering the orifice, pin tip and the region where primary atomization occurs is selected for numerical analysis. The governing equations are selected in three dimensional cartesian form and simulations are performed to predict the dynamics of water jet impinging on the pin. Systematic studies were carried out and the results leading to the choice of turbulence model and the effect of pin tip diameter are reported here. Further studies are proposed to show the future directions of the present research work.

  11. Nanowall pinning for enhanced pinning force in YBCO films with nanofabricated structures

    Energy Technology Data Exchange (ETDEWEB)

    Palau, A.; Rouco, V.; Luccas, R.F.; Obradors, X.; Puig, T., E-mail: teresa.puig@icmab.es

    2014-11-15

    Highlights: • High resolution lithography techniques to fabricate artificial pinning centres in high temperature superconductors. • Enhanced critical currents of YBCO films with engineered nanofabricated structures. • Controlled nano-walls with weakened superconductivity acting as strong pinning centres. - Abstract: High resolution nanofabrication tools (Focused Ion Beam and Electron Beam Lithography) have been used to fabricate nano-metric milled structures in high critical current YBCO thin films able to further increase their vortex pinning capabilities. We have demonstrated that pinning forces at 77 K and 3 T are increased by a 70–80% by proper nanostructure designs. Model systems with linear trenches and triangular blind antidots of different sizes, distribution and density have been generated and studied. We demonstrate that specific milled nanostructures can increase the total current through the system at expenses of a limited decrease of cross section. We have identified the length of fabricated nano-walls as the main parameter controlling the pinning potential of nanostructures and thus defined the optimised milling conditions and nanostructure morphology to maximise pinning efficiency.

  12. CFD Study of Pectoral Fins of Larval Zebrafish: Effect of Reynolds Number and Fin Bending in Fluid Structures and Transport

    Science.gov (United States)

    Islam, Toukir; Curet, Oscar M.

    2015-11-01

    Zebrafish exhibits significant changes in fin morphology as well as fin actuation during its physical development. In larval stage (Re ~ 10), they beat pectoral fins asymmetrically during slow swimming and prey tracking and a hypothesis suggests pectoral fin motion enhances fluid mixing to assist respiration. We performed a series of computational simulations to study effect of Reynolds number (Re) and pectoral fin kinematics in the fluid dynamics and mixing around a larval zebrafish. The CFD algorithm is based on a constraint formulation where the kinematics of the zebrafish are specified. We simulated experimental zebrafish kinematics at different Re (17 to 300) and considered variations on the fin kinematics to evaluate role of fin deformation in the fluid structures generated by the pectoral fins. Using Lagrangian Coherent Structures and Lagrangian fluid tracers, we identified distinctly dynamic fluid regions and found that mixing around the pectoral fin significantly increases with Re and fin bending enhance fluid mixing at low Re. However, as zebrafish matures and its Re increases, the need to beat the pectoral fins to enhance mixing is reduced.

  13. The Effects of Fin Collar Form on Heat Transfer Performance of Cross Fin-tube Heat Exchanger

    Science.gov (United States)

    Tsubaki, Koutaro; Miyara, Akio; Nagai, Yuma; Sasaki, Naoe; Mizuta, Yoshihiko

    A numerical study has been conducted to investigate effects of fin collar form of cross fin-tube heat exchangers on heat transfer performance. Two adjacent fin collars and a copper tube form a triangular space during the making process. And also end of the fin collar protrudes into air-side. The protruded end and triangular space affect on air-side heat convection and thermal resistance between the tube and fin collars, respectively. The increase in triangular space increases non-contact surface area between tube and fin collar, which affects to decrease heat transfer rate. The protruded end disturbs air-side flow and expands the surface of the fin collar. As a result of these two effects, heat transfer rate from the heat transfer tube increases. However, protruded end increases pressure loss of air-side.

  14. Parametric CFD Analysis to Study the Influence of Fin Geometry on the Performance of a Fin and Tube Heat Exchanger

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2016-01-01

    Heat transfer and pressure loss characteristics of a fin and tube heat exchanger are numerically investigated based on parametric fin geometry. The cross-flow type heat exchanger with circular tubes and rectangular fin profile is selected as a reference design. The fin geometry is varied using...... a design aspect ratio as a variable parameter in a range of 0.1-1.0 to predict the impact on overall performance of the heat exchanger. In this paper, geometric profiles with a constant thickness of fin base are studied. Three-dimensional, steady state CFD model is developed using commercially available...... are determined. The best performed geometric fin profile based on the higher heat transfer and lower pressure loss is predicted. The study provides insights into the impact of fin geometry on the heat transfer performance which help escalate the understanding of heat exchanger designing and manufacturing...

  15. Ytterbium: Transition at High Pressure from Face-Centered Cubic to Body-Centered Cubic Structure.

    Science.gov (United States)

    Hall, H T; Barnett, J D; Merrill, L

    1963-01-11

    Pressure of 40,000 atmospheres at 25 degrees C induces a phase transformation in ytterbium metal; the face-centered cubic structure changes to body-centered cubic. The radius of the atom changes from 1.82 to 1.75 A. At the same time the atom's volume decreases by 11 percent and the volume, observed macroscopically, decreases 3.2 percent.

  16. Differential Roles of PIN1 and PIN2 in Root Meristem Maintenance Under Low-B Conditions in Arabidopsis thaliana.

    Science.gov (United States)

    Li, Ke; Kamiya, Takehiro; Fujiwara, Toru

    2015-06-01

    Boron (B) is an essential element for plants; its deficiency causes rapid cessation of root elongation. In addition, B influences auxin accumulation in plants. To assess the importance of auxin transport in B-dependent root elongation, Arabidopsis thaliana pin1-pin4 mutants were grown under low-B conditions. Among them, only the pin2/eir1-1 mutant showed a significantly shorter root under low-B conditions than under control conditions. Moreover, the root meristem size of pin2/eir1-1 was reduced under low-B conditions. Among the PIN-FORMED (PIN) family, PIN1 and PIN2 are important for root meristem growth/maintenance under normal conditions. To investigate the differential response of pin1 and pin2 mutants under low-B conditions, the effect of low-B on PIN1-green fluorescent protein (GFP) and PIN2-GFP accumulation and localization was examined. Low-B did not affect PIN2-GFP, while it reduced the accumulation of PIN1-GFP. Moreover, no signal from DII-VENUS, an auxin sensor, was detected under the low-B condition in the stele of wild-type root meristems. Taken together, these results indicate that under low-B conditions PIN1 is down-regulated and PIN2 plays an important role in root meristem maintenance. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  17. Heat Transfer of Tube-fin Heat Exchanger Having Parallel Louver Continuous Fins

    Science.gov (United States)

    Take-Uchi, Masaaki; Yamada, Jun; Tanaka, Jun-Ichirou

    Heat transfer from tubes has been numerically simulated in a fan coil unit for an airconditioning equipment. The array of tubes has parallel louver continuous fins, perpendicular to staggered round tubes. Quite a few of slits divide plates into many strips, which are offsetted, so that the heat transfer will be augmented from the plate to the air flow. On the other hand, the conduction of heat in the platemight be prevented with these slits. The conduction retardation due to slit is estimated, and the simulation shows that the retardation is not serious for present fins.

  18. Two-phase pressure drop across a hydrofoil-based micro pin device using R-123

    Energy Technology Data Exchange (ETDEWEB)

    Kosar, Ali [Mechatronics Engineering Program, Sabanci University, Orhanli, Tuzla, 34956 Istanbul (Turkey)

    2008-05-15

    The two-phase pressure drop in a hydrofoil-based micro pin fin heat sink has been investigated using R-123 as the working fluid. Two-phase frictional multipliers have been obtained over mass fluxes from 976 to 2349 kg/m{sup 2} s and liquid and gas superficial velocities from 0.38 to 1.89 m/s and from 0.19 to 24 m/s, respectively. It has been found that the two-phase frictional multiplier is strongly dependent on flow pattern. The theoretical prediction using Martinelli parameter based on the laminar fluid and laminar gas flow represented the experimental data fairly well for the spray-annular flow. For the bubbly and wavy-intermittent flow, however, large deviations from the experimental data were recorded. The Martinelli parameter was successfully used to determine the flow patterns, which were bubbly, wavy-intermittent, and spray-annular flow in the current study. (author)

  19. Genome-wide identification and evolution of the PIN-FORMED (PIN) gene family in Glycine max.

    Science.gov (United States)

    Liu, Yuan; Wei, Haichao

    2017-07-01

    Soybean (Glycine max) is one of the most important crop plants. Wild and cultivated soybean varieties have significant differences worth further investigation, such as plant morphology, seed size, and seed coat development; these characters may be related to auxin biology. The PIN gene family encodes essential transport proteins in cell-to-cell auxin transport, but little research on soybean PIN genes (GmPIN genes) has been done, especially with respect to the evolution and differences between wild and cultivated soybean. In this study, we retrieved 23 GmPIN genes from the latest updated G. max genome database; six GmPIN protein sequences were changed compared with the previous database. Based on the Plant Genome Duplication Database, 18 GmPIN genes have been involved in segment duplication. Three pairs of GmPIN genes arose after the second soybean genome duplication, and six occurred after the first genome duplication. The duplicated GmPIN genes retained similar expression patterns. All the duplicated GmPIN genes experienced purifying selection (Ka/Ks < 1) to prevent accumulation of non-synonymous mutations and thus remained more similar. In addition, we also focused on the artificial selection of the soybean PIN genes. Five artificially selected GmPIN genes were identified by comparing the genome sequence of 17 wild and 14 cultivated soybean varieties. Our research provides useful and comprehensive basic information for understanding GmPIN genes.

  20. Undulating fins produce off-axis thrust and flow structures.

    Science.gov (United States)

    Neveln, Izaak D; Bale, Rahul; Bhalla, Amneet Pal Singh; Curet, Oscar M; Patankar, Neelesh A; MacIver, Malcolm A

    2014-01-15

    While wake structures of many forms of swimming and flying are well characterized, the wake generated by a freely swimming undulating fin has not yet been analyzed. These elongated fins allow fish to achieve enhanced agility exemplified by the forward, backward and vertical swimming capabilities of knifefish, and also have potential applications in the design of more maneuverable underwater vehicles. We present the flow structure of an undulating robotic fin model using particle image velocimetry to measure fluid velocity fields in the wake. We supplement the experimental robotic work with high-fidelity computational fluid dynamics, simulating the hydrodynamics of both a virtual fish, whose fin kinematics and fin plus body morphology are measured from a freely swimming knifefish, and a virtual rendering of our robot. Our results indicate that a series of linked vortex tubes is shed off the long edge of the fin as the undulatory wave travels lengthwise along the fin. A jet at an oblique angle to the fin is associated with the successive vortex tubes, propelling the fish forward. The vortex structure bears similarity to the linked vortex ring structure trailing the oscillating caudal fin of a carangiform swimmer, though the vortex rings are distorted because of the undulatory kinematics of the elongated fin.

  1. Function of dorsal fins in bamboo shark during steady swimming.

    Science.gov (United States)

    Maia, Anabela; Wilga, Cheryl A

    2013-08-01

    To gain insight into the function of the dorsal fins in white-spotted bamboo sharks (Orectolobiformes: Hemiscyillidae) during steady swimming, data on three-dimensional kinematics and electromyographic recordings were collected. Bamboo sharks were induced to swim at 0.5 and 0.75 body lengths per second in a laminar flow tank. Displacement, lag and angles were analyzed from high-speed video images. Onset, offset, duration, duty cycle and asynchrony index were calculated from three muscle implants on each side of each dorsal fin. The dorsal fins were displaced more laterally than the undulating body. In addition, the dorsal tips had larger lateral displacement than the trailing edges. Increased speed was accompanied by an increase in tail beat frequency with constant tail beat amplitude. However, lateral displacement of the fins and duration of muscle bursts remained relatively constant with increased speed. The range of lateral motion was greater for the second dorsal fin (mean 33.3°) than for the first dorsal fin (mean 28.4°). Bending within the fin was greater for the second dorsal fin (mean 43.8°) than for the first dorsal fin (mean 30.8°). Muscle onset and offset among implants on the same side of each dorsal fin was similar. Three-dimensional conformation of the dorsal fins was caused by interactions between muscle activity, material properties, and incident flow. Alternating bilateral activity occurred in both dorsal fins, further supporting the active role of these hydrofoils in thrust production during steady swimming. The dorsal fins in bamboo sharks are capable of thrust production during steady swimming and do not appear to function as stabilizing structures.

  2. Computational Research on Modular Undulating Fin for Biorobotic Underwater Propulsor

    Institute of Scientific and Technical Information of China (English)

    Yong-hua Zhang; Lai-bing Jia; Shi-wu Zhang; Jie Yang; K.H.Low

    2007-01-01

    Biomimetic design employs the principles of nature to solve engineering problems.Such designs which are hoped to be quick,efficient,robust,and versatile,have taken advantage of optimization via natural selection.In the present research.an environment-friendly propulsion system mimicking undulating fins of stingray was built.A non-conventional method was considered to model the flexibility of the fins of stingray.A two-degree-of-freedom mechanism comprised of several linkages was designed and constructed to mimic the actual flexible fin.The driving linkages were used to form a mechanical fin consisting of several fin segments,which are able to produce undulations,similar to those produced by the actual fins.Owing to the modularity of the design of the mechanical fin,various undulating patterns can be realized.Some qualitative observations,obtained by experiments,predicted that the thrusts produced by the mechanical fin are different among various undulating patterns.To fully understand this experimental phenomenon is very important for better performance and energy saving for our biorobotic underwater propulsion system.Here,four basic undulating patterns of the mechanical fin were performed using two-dimensional unsteady computational fluid dynamics(CFD)method.An unstructured,grid-based,unsteady Navier-Stokes solver with automatic adaptive re-meshing was used to compute the unsteady flow around the fin through twenty complete cycles.The pressure distribution on fin surface was computed and integrated to provide fin forces which were decomposed into lift and thrust.The pressure force and friction force were also computed throughout the swimming cycle.Finally,vortex contour maps of these four basic fin undulating patterns were displayed and compared.

  3. Proteomic analysis of zebrafish caudal fin regeneration.

    Science.gov (United States)

    Saxena, Sandeep; Singh, Sachin K; Lakshmi, Mula G Meena; Meghah, Vuppalapaty; Bhatti, Bhawna; Swamy, Cherukuvada V Brahmendra; Sundaram, Curam S; Idris, Mohammed M

    2012-06-01

    The epimorphic regeneration of zebrafish caudal fin is rapid and complete. We have analyzed the biomechanism of zebrafish caudal fin regeneration at various time points based on differential proteomics approaches. The spectrum of proteome changes caused by regeneration were analyzed among controls (0 h) and 1, 12, 24, 48, and 72 h postamputation involving quantitative differential proteomics analysis based on two-dimensional gel electrophoresis matrix-assisted laser desorption/ionization and differential in-gel electrophoresis Orbitrap analysis. A total of 96 proteins were found differentially regulated between the control nonregenerating and regenerating tissues of different time points for having at least 1.5-fold changes. 90 proteins were identified as differentially regulated for regeneration based on differential in-gel electrophoresis analysis between the control and regenerating tissues. 35 proteins were characterized for its expression in all of the five regenerating time points against the control samples. The proteins identified and associated with regeneration were found to be directly allied with various molecular, biological, and cellular functions. Based on network pathway analysis, the identified proteome data set for regeneration was majorly associated in maintaining cellular structure and architecture. Also the proteins were found associated for the cytoskeleton remodeling pathway and cellular immune defense mechanism. The major proteins that were found differentially regulated during zebrafish caudal fin regeneration includes keratin and its 10 isoforms, cofilin 2, annexin a1, skeletal α1 actin, and structural proteins. Annexin A1 was found to be exclusively undergoing phosphorylation during regeneration. The obtained differential proteome and the direct association of the various proteins might lead to a new understanding of the regeneration mechanism.

  4. FinTech Market Development Perspectives

    OpenAIRE

    Kalmykova Ekaterina; Ryabova Anna

    2016-01-01

    Fast development of technologies has led to emergence of the new market – FinTech – which is very attractive for investors today. By now this market has a great number of different concepts: P2P-crediting, E-wallets, Bitcoins, mPOS-acquiring, T-commerce, mobile banks, etc. Many of these tools have already heavily entered our ordinary life. People can obtain any credits through special services on the Internet from other users without participation of banks, pay by credit card using mobile dev...

  5. Pinning Synchronization of One-Sided Lipschitz Complex Networks

    Directory of Open Access Journals (Sweden)

    Fang Liu

    2014-01-01

    Full Text Available This paper studies the pinning synchronization in complex networks with node dynamics satisfying the one-sided Lipschitz condition which is less conservative than the well-known Lipschitz condition. Based on M-matrix theory and Lyapunov functional method, some simple pinning conditions are derived for one-sided Lipschitz complex networks with full-state and partial-state coupling, respectively. A selective pinning scheme is further provided to address the selection of pinned nodes and the design of pinning feedback gains for one-sided Lipschitz complex networks with general topologies. Numerical results are given to illustrate the effectiveness of the theoretical analysis.

  6. Face-Centered-Cubic Nanostructured Polymer Foams

    Science.gov (United States)

    Cui, C.; Baughman, R. H.; Liu, L. M.; Zakhidov, A. A.; Khayrullin, I. I.

    1998-03-01

    Beautifully iridescent polymer foams having Fm-3m cubic symmetry and periodicities on the scale of the wavelength of light have been synthesized by the templating of porous synthetic opals. These fabrication processes involve the filling of porous SiO2 opals (with typical cubic lattice parameters of 250 nm) with either polymers or polymer precursors, polymerization of the precursors if necessary, and removal of the fcc array of SiO2 balls to provide an all-polymer structure. The structures of these foams are similar to periodic minimal surfaces, although the Gaussian curvature can have both positive and negative values. Depending upon whether the internal surfaces of the opal are polymer filled or polymer coated, the polymer replica has either one or two sets of independent channels. We fill these channels with semiconductors, metals, or superconductors to provide electronic and optical materials with novel properties dependent on the nanoscale periodicity.

  7. Cubic Polynomials with Rational Roots and Critical Points

    Science.gov (United States)

    Gupta, Shiv K.; Szymanski, Waclaw

    2010-01-01

    If you want your students to graph a cubic polynomial, it is best to give them one with rational roots and critical points. In this paper, we describe completely all such cubics and explain how to generate them.

  8. Use of Pom Pons to Illustrate Cubic Crystal Structures.

    Science.gov (United States)

    Cady, Susan G.

    1997-01-01

    Describes a method that uses olefin pom pons to illustrate cubic crystal structure. Facilitates hands-on examination of different packing arrangements such as hexagonal close-packed and cubic close-packed structures. (JRH)

  9. Shape preserving rational bi-cubic function

    Directory of Open Access Journals (Sweden)

    Malik Zawwar Hussain

    2012-11-01

    Full Text Available The study is dedicated to the development of shape preserving interpolation scheme for monotone and convex data. A rational bi-cubic function with parameters is used for interpolation. To preserve the shape of monotone and convex data, the simple data dependent constraints are developed on these parameters in each rectangular patch. The developed scheme of this paper is confined, cheap to run and produce smooth surfaces.

  10. Cubic Lienard Equations with Quadratic Damping (Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    Yu-quan Wang; Zhu-jun Jing

    2002-01-01

    Applying Hopf bifurcation theory and qualitative theory, we show that the general cubic Lienard equations with quadratic damping have at most three limit cycles. This implies that the guess in which the system has at most two limit cycles is false. We give the sufficient conditions for the system has at most three limit cycles or two limit cycles. We present two examples with three limit cycles or two limit cycles by using numerical simulation.

  11. The pin pixel detector--neutron imaging

    CERN Document Server

    Bateman, J E; Derbyshire, G E; Duxbury, D M; Marsh, A S; Rhodes, N J; Schooneveld, E M; Simmons, J E; Stephenson, R

    2002-01-01

    The development and testing of a neutron gas pixel detector intended for application in neutron diffraction studies is reported. Using standard electrical connector pins as point anodes, the detector is based on a commercial 100 pin connector block. A prototype detector of aperture 25.4 mmx25.4 mm has been fabricated, giving a pixel size of 2.54 mm which matches well to the spatial resolution typically required in a neutron diffractometer. A 2-Dimensional resistive divide readout system has been adapted to permit the imaging properties of the detector to be explored in advance of true pixel readout electronics. The timing properties of the device match well to the requirements of the ISIS-pulsed neutron source.

  12. Local atomic structure in cubic stabilized zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Villella, P.; Conradson, S. D.; Espinosa-Faller, F. J.; Foltyn, S. R.; Sickafus, K. E.; Valdez, J. A.; Degueldre, C. A.

    2001-09-01

    X-ray-absorption fine structure measurements have been used to elucidate the local atomic structure of quaternary Zr, Y, Er, Ce/U cubic stabilized zirconia. These compounds display more complicated local environments than those reported for simpler binary systems. While the shortest cation-O distances are similar to those found in the binary cubic stabilized compounds, responding to the different sizes of the cations, we have identified large distortions in the first-shell oxygen distribution involving long, 2.8--3.2 {angstrom} cation-O distances that are similar to those found in the amorphous phase of zirconium. The cation-cation distributions are also found to be quite complicated (non-Gaussian) and element specific. The U-near neighbor distances are expanded relative to the Ce ions for which it substitutes, consistent with the larger size of the actinide, and the U-cation distribution is also more complicated. In terms of the effects of this substitution on the other cation sites, the local environment around Y is altered while the Zr and Er local environments remain unchanged. These results point out the importance of collective and correlated interactions between the different pairs of cations and the host lattice that are mediated by the local strain fields generated by the different cations. The presence of pair-specific couplings has not been commonly included in previous analyses and may have implications for the stabilization mechanisms of cubic zirconia.

  13. The special symplectic structure of binary cubics

    CERN Document Server

    Slupinski, Marcus

    2009-01-01

    Let $k$ be a field of characteristic not 2 or 3. Let $V$ be the $k$-space of binary cubic polynomials. The natural symplectic structure on $k^2$ promotes to a symplectic structure $\\omega$ on $V$ and from the natural symplectic action of $\\textrm{Sl}(2,k)$ one obtains the symplectic module $(V,\\omega)$. We give a complete analysis of this symplectic module from the point of view of the associated moment map, its norm square $Q$ (essentially the classical discriminant) and the symplectic gradient of $Q$. Among the results are a symplectic derivation of the Cardano-Tartaglia formulas for the roots of a cubic, detailed parameters for all $\\textrm{Sl}(2,k)$ and $\\textrm{Gl}(2,k)$-orbits, in particular identifying a group structure on the set of $\\textrm{Sl}(2,k)$-orbits of fixed nonzero discriminant, and a purely symplectic generalization of the classical Eisenstein syzygy for the covariants of a binary cubic. Such fine symplectic analysis is due to the special symplectic nature inherited from the ambient excepti...

  14. Method of synthesizing cubic system boron nitride

    Energy Technology Data Exchange (ETDEWEB)

    Yuzu, S.; Sumiya, H.; Degawa, J.

    1987-10-13

    A method is described for synthetically growing cubic system boron nitride crystals by using boron nitride sources, solvents for dissolving the boron nitride sources, and seed crystals under conditions of ultra-high pressure and high temperature for maintaining the cubic system boron nitride stable. The method comprises the following steps: preparing a synthesizing vessel having at least two chambers, arrayed in order in the synthesizing vessel so as to be heated according to a temperature gradient; placing the solvents having different eutectic temperatures in each chamber with respect to the boron nitride sources according to the temperature gradient; placing the boron nitride source in contact with a portion of each of the solvents heated at a relatively higher temperature and placing at least a seed crystal in a portion of each of the solvents heated at a relatively lower temperature; and growing at least one cubic system boron nitride crystal in each of the solvents in the chambers by heating the synthesizing vessel for establishing the temperature gradient while maintaining conditions of ultra-high pressure and high temperature.

  15. Cheap and Easy PIN Entering Using Eye Gaze

    Directory of Open Access Journals (Sweden)

    Kasprowski Pawel

    2014-03-01

    Full Text Available PINs are one of the most popular methods to perform simple and fast user authentication. PIN stands for Personal Identification Number, which may have any number of digits or even letters. Nevertheless, 4-digit PIN is the most common and is used for instance in ATMs or cellular phones. The main advantage of the PIN is that it is easy to remember and fast to enter. There are, however, some drawbacks. One of them - addressed in this paper - is a possibility to steal PIN by a technique called `shoulder surfing'. To avoid such problems a novel method of the PIN entering was proposed. Instead of using a numerical keyboard, the PIN may be entered by eye gazes, which is a hands-free, easy and robust technique. References:

  16. Timing analysis of PWR fuel pin failures

    Energy Technology Data Exchange (ETDEWEB)

    Jones, K.R.; Wade, N.L.; Katsma, K.R.; Siefken, L.J. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Straka, M. (Halliburton NUS, Idaho Falls, ID (United States))

    1992-09-01

    Research has been conducted to develop and demonstrate a methodology for calculation of the time interval between receipt of the containment isolation signals and the first fuel pin failure for loss-of-coolant accidents (LOCAs). Demonstration calculations were performed for a Babcock and Wilcox (B W) design (Oconee) and a Westinghouse (W) four-loop design (Seabrook). Sensitivity studies were performed to assess the impacts of fuel pin bumup, axial peaking factor, break size, emergency core cooling system availability, and main coolant pump trip on these times. The analysis was performed using the following codes: FRAPCON-2, for the calculation of steady-state fuel behavior; SCDAP/RELAP5/MOD3 and TRACPF1/MOD1, for the calculation of the transient thermal-hydraulic conditions in the reactor system; and FRAP-T6, for the calculation of transient fuel behavior. In addition to the calculation of fuel pin failure timing, this analysis provides a comparison of the predicted results of SCDAP/RELAP5/MOD3 and TRAC-PFL/MOD1 for large-break LOCA analysis. Using SCDAP/RELAP5/MOD3 thermal-hydraulic data, the shortest time intervals calculated between initiation of containment isolation and fuel pin failure are 10.4 seconds and 19.1 seconds for the B W and W plants, respectively. Using data generated by TRAC-PF1/MOD1, the shortest intervals are 10.3 seconds and 29.1 seconds for the B W and W plants, respectively. These intervals are for a double-ended, offset-shear, cold leg break, using the technical specification maximum peaking factor and applied to fuel with maximum design bumup. Using peaking factors commensurate widi actual bumups would result in longer intervals for both reactor designs. This document also contains appendices A through J of this report.

  17. Anatomy and early development of the pectoral girdle, fin, and fin spine of sturgeons (Actinopterygii: Acipenseridae).

    Science.gov (United States)

    Dillman, Casey B; Hilton, Eric J

    2015-03-01

    Acipenseriformes hold an important place in the evolutionary history of bony fishes. Given their phylogenetic position as extant basal Actinopterygii, it is generally held that a thorough understanding of their morphology will greatly contribute to the knowledge of the evolutionary history and the origin of diversity for the major osteichthyan clades. To this end, we examined comparative developmental series from the pectoral girdle in Acipenser fulvescens, A. medirostris, A. transmontanus, and Scaphirhynchus albus to document, describe, and compare ontogenetic and allometric differences in the pectoral girdle. We find, not surprisingly, broad congruence between taxa in the basic pattern of development of the dermal and chondral elements of the pectoral girdle. However, we also find clear differences in the details of structure and development among the species examined in the dermal elements, including the clavicle, cleithrum, supracleithrum, posttemporal, and pectoral-fin spine. We also find differences in the internal fin elements such as the distal radials as well as in the number of fin rays and their association with the propterygium. Further, there are clear ontogenetic differences during development of the dermal and chondral elements in these species and allometric variation in the pectoral-fin spine. The characters highlighted provide a suite of elements for further examination in studies of the phylogeny of sturgeons. Determining the distribution of these characters in other sturgeons may aid in further resolution of phylogenetic relationships, and these data highlight the role that ontogenetic and comparative developmental studies provide in systematics.

  18. A CFD Analysis of The Performance of Pin-Fin Laminar Flow Micro/Meso Scale Heat Exchangers

    Science.gov (United States)

    2005-09-01

    8 D. METHOLOGY -ORGANIZATION...of experimental tests already completed. D. METHOLOGY -ORGANIZATION Several three-dimensional models were constructed according to our test matrix...provided the validation and corroboration with the theoretical and historical results and a more extensive heat exchange examination of the observations

  19. Numerical Analysis of Heat Transfer and Fluid Flow in Heat Exchangers with Emphasis on Pin Fin Technology

    OpenAIRE

    2012-01-01

    One of the most important industrial processes is heat transfer, carried out by heat exchangers in single and multiphase flow applications. Despite the existence of well-developed theoretical models for different heat transfer mechanisms, the expanding need for industrial applications requiring the design and optimization of heat exchangers, has created a solid demand for experimental work and effort. This thesis concerns the use of numerical approaches to analyze and optimize heat transfer a...

  20. Air cooling effect of fins on a Honda shine bike

    Directory of Open Access Journals (Sweden)

    Padhiyar Abhesinh J

    2015-05-01

    Full Text Available The main of aim of this work is to study various researches done in past to improve heat transfer rate of cooling fins by changing cylinder block fin geometry. Low rate of heat transfer through cooling fins is the main problem in this type of cooling. So efficiency of the engine is increase by increase the heat transfer. Examples of direct air cooling in modern automobiles are rare. The most common example is the commercials Automobile bike like a Honda Shine, Bajaj bike, Honda splendor etc. It is conclude about shape try to this fins is more effectively heat transfer in Honda shine bike compare to existing fins. After FEA Analysis it checking on fin whether efficiency of heat transfer increases or not. This work validation with Experimental and Mathematical.

  1. Selection of plain or segmented finned tubes for heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Reid, D.R.; Taborek, Jerry (Fintube Corp. (United States))

    1994-01-01

    Heat recovery heat exchangers with gas as one of the streams depend on the use of finned tubes to compensate for the inherently low gas heat transfer coefficient. Standard frequency welded ''plain'' fins were generally used in the past - until the high-frequency resistance welding technology permitted the cost-effective manufacture of segmented fins. The main advantage of the segmented fin design is that it permits higher heat flux and hence smaller, lighter units for most operating conditions. While the criteria that dictate optimum design, such as compactness, weight and cost per unit area, favour the segmented fin design, a few other considerations, such as fouling, ease of cleaning and availability of dependable design methods, have to be considered. This article analyses the performance parameters that affect the selection of either fin type. (4 figures, 1 table, 10 references) (Author)

  2. Thermal Analysis of Fin and Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Ms N. B. Rairker

    2014-06-01

    Full Text Available This paper studied experimentally the effect of heat transfer of fin and tube type heat exchanger for different mass flow rate of fluid. The thermal stresses induced on fin and tube is also studied by ansys software at steady state condition by changing the width of fin and diameter of tube. Readings were taken experimentally by changing mass flow rate of fluid at respective temperatures. Comparison was done on theoretically and experimentally obtained results. It is observed that as the width of fin increases thermal stresses on fin also increases. Likewise for tube, by varying diameter of tube different values of stress are obtained. It is also observed at full valve position maximum thermal stresses are induced on fin as well as tube.

  3. Mesoscopic pinning forces in neutron star crusts

    CERN Document Server

    Seveso, Stefano; Grill, Fabrizio; Haskell, Brynmor

    2014-01-01

    The crust of a neutron star is thought to be comprised of a lattice of nuclei immersed in a sea of free electrons and neutrons. As the neutrons are superfluid their angular momentum is carried by an array of quantized vortices. These vortices can pin to the nuclear lattice and prevent the neutron superfluid from spinning down, allowing it to store angular momentum which can then be released catastrophically, giving rise to a pulsar glitch. A crucial ingredient for this model is the maximum pinning force that the lattice can exert on the vortices, as this allows us to estimate the angular momentum that can be exchanged during a glitch. In this paper we perform, for the first time, a detailed and quantitative calculation of the pinning force \\emph{per unit length} acting on a vortex immersed in the crust and resulting from the mesoscopic vortex-lattice interaction. We consider realistic vortex tensions, allow for displacement of the nuclei and average over all possible orientation of the crystal with respect to...

  4. Improve seawater cooling with titanium finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    O' Donnell J. (High Performance Tube, Inc., Warren, NJ (United States))

    1992-10-01

    Seawater offers an endless supply of cooling water for these coastal processing facilities. But users must address seawater's corrosive nature in selecting construction materials for heat exchangers. Copper-nickel or carbon steel tubing fails continually under seawater service. This paper reports that titanium tubes, once thought to be too expensive a material for heat exchanger tubing, offer a unique combination of high material strength, excellent resistance to corrosion, and endurance to erosion by seawater. Titanium's superior physical properties in combination with enhanced surface area of low finned tubing perform the same heat duty with half the lineal footage of traditional heat exchanger tubes. High density low finned tubes multiply heat transfer capacity by a factor of two compared to plain tube. The technology applies in retrofit and original equipment manufacture (OEM) situations. It works best when the ratio of heat transfer coefficients is 2:1 or higher between the seawater coolant and shellside flow being cooled.

  5. Turbulent Flow Simulations in Complex Multilouvered Fins

    Science.gov (United States)

    Tafti, Danesh

    2000-11-01

    Air-side resistance makes up roughly 80resistance in compact heat exchangers. Multilouvered fins find widespread use in the automotive and HVAC industry for heat transfer augmentation. We will describe the computational methodology for simulating the complex three-dimensional geometry and present results at a Reynolds number of 1100 based on louver pitch and the average flow velocity. The three-dimensionality in the louver geometry occurs along the height of the fin, where the angled louver transitions to the flat landing and joins with the tube surface. The transition region is characterized by a swept leading edge and decreasing flow area between louvers. Results show the formation of spanwise vortices at the leading edge of the angled portion of the louver which convect downstream in the vicinity of the louver surface. Further there is evidence of a separate louver wake instability which interacts with the vortices shed from the leading edge. In the transition region, a high energy streamwise vortex jet is formed. The jet forms in the vicinity of the louver junction with the flat landing and is drawn under the louver in the transition region. The passage of the jet in the vicinity of the louver surface produces a high pressure stagnant zone directly under the jet with a net effect of reducing heat transfer. On the other hand, the top surface of the louver in the transition region experiences high velocities in the vicinity of the surface and exhibits much higher heat transfer coefficients than the bottom surface.

  6. Bioelectric signaling regulates size in zebrafish fins.

    Directory of Open Access Journals (Sweden)

    Simon Perathoner

    2014-01-01

    Full Text Available The scaling relationship between the size of an appendage or organ and that of the body as a whole is tightly regulated during animal development. If a structure grows at a different rate than the rest of the body, this process is termed allometric growth. The zebrafish another longfin (alf mutant shows allometric growth resulting in proportionally enlarged fins and barbels. We took advantage of this mutant to study the regulation of size in vertebrates. Here, we show that alf mutants carry gain-of-function mutations in kcnk5b, a gene encoding a two-pore domain potassium (K(+ channel. Electrophysiological analysis in Xenopus oocytes reveals that these mutations cause an increase in K(+ conductance of the channel and lead to hyperpolarization of the cell. Further, somatic transgenesis experiments indicate that kcnk5b acts locally within the mesenchyme of fins and barbels to specify appendage size. Finally, we show that the channel requires the ability to conduct K(+ ions to increase the size of these structures. Our results provide evidence for a role of bioelectric signaling through K(+ channels in the regulation of allometric scaling and coordination of growth in the zebrafish.

  7. Filmwise condensation of steam on low integral-finned tubes

    OpenAIRE

    Georgiadis, Ioannis V.

    1984-01-01

    Approved for public release; distribution is unlimited Filmwise condensation heat-transfer measurements if steam were made on horizontal tubes under vacuum and near-atmospheric pressures. Data were taken for a smooth tube and for 21 tubes which contained rectangularly-shaped, low integral fins. The fin geometry was systematically varied in order to investigate the dependence of the steam-side heat-transfer coefficient on fin spacing, thickness and height. The condensation process was fo...

  8. Fuzzy-PID controlled lift feedback fin stabilizer

    Institute of Scientific and Technical Information of China (English)

    LIANG Yan-hua; JIN Hong-zhang; LIANG Li-hua

    2008-01-01

    Conventional PID controllers are widely used in fin stabilizer control systems,but they have time-variations,nonlinearity,and uncertainty influencing their control effects.A lift feedback fuzzy-PID control method was developed to better deal with these problems,and this lift feedback fin stabilizer system was simulated under different sea condition.Test results showed the system has better anti-rolling performance than traditional fin-angle PID control systems.

  9. Augmentation of Condensation Heat Transger by Finning of Tubes

    OpenAIRE

    1992-01-01

    This paper summarizes experimental and theoretical studies that have been performed in our laboratory to enhance condensation heat transfer on horizontal tubes and tube bundles by use of fins. Use of a drainge strip is proved to be very effective in further enhancing condensation heat transfer on the horizontal finned tube. Effects of fin geometry and tube arrangement on the condensation heat transfer performance of the tube bundle are investigated. A theoretical model is proposed to predict ...

  10. Thermal Analysis of Fin and Tube Heat Exchanger

    OpenAIRE

    2014-01-01

    This paper studied experimentally the effect of heat transfer of fin and tube type heat exchanger for different mass flow rate of fluid. The thermal stresses induced on fin and tube is also studied by ansys software at steady state condition by changing the width of fin and diameter of tube. Readings were taken experimentally by changing mass flow rate of fluid at respective temperatures. Comparison was done on theoretically and experimentally obtained results. It is observed ...

  11. Large Scale Density Estimation of Blue and Fin Whales (LSD)

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Large Scale Density Estimation of Blue and Fin Whales ...sensors, or both. The goal of this research is to develop and implement a new method for estimating blue and fin whale density that is effective over...develop and implement a density estimation methodology for quantifying blue and fin whale abundance from passive acoustic data recorded on sparse

  12. Impacts of plasma-induced damage due to UV light irradiation during etching on Ge fin fabrication and device performance of Ge fin field-effect transistors

    Science.gov (United States)

    Mizubayashi, Wataru; Noda, Shuichi; Ishikawa, Yuki; Nishi, Takashi; Kikuchi, Akio; Ota, Hiroyuki; Su, Ping-Hsun; Li, Yiming; Samukawa, Seiji; Endo, Kazuhiko

    2017-02-01

    We investigated the impacts of plasma-induced damage due to UV light irradiation during etching on Ge fin fabrication and the device performance of Ge fin field-effect transistors (Ge FinFETs). UV light irradiation during etching affected the shape of the Ge fin and the surface roughness of the Ge fin sidewall. A vertical and smooth Ge fin could be fabricated by neutral beam etching without UV light irradiation. The performances of Ge FinFETs fabricated by neutral beam etching were markedly improved as compared to those of Ge FinFETs fabricated by inductively coupled plasma etching, in which the UV light has an impact.

  13. Improved Pinning Center Morphology in HTS with Order-of-Magnitude Increase in Jc and Bpin Compared to Columnar Pinning

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The motivation for continuouscolumnar pinning centers has been to provide maximum Upin. It has been assumed that this provides the best Jc and Bpin. Limitations on Jc and Bpin observed for columnar pinning have been attributed to degradation of the order parameter and Tc. We examine columnar pinning by ionic damage and conclude instead that geometrical effects of columnar pinningon percolation path and on the number of pinning centers are the dominant limitations of columnar pinning, leading to a limit of Bpin~4 T. Evidence suggests that multiple-in-line-defects (MILD) are far better suited to increase Jc and Bpin. The morphology of MILD pinning is reviewed. Ion energy loss per unit distance, Se, is found to be most promising in a regime almost diametrically opposite to that sought to maximize Upin. We expect Jc~106 A/cm2 and Bpin>40 T from MILD pinning,despite sharply decreased Upin.Experimental confirmation is proposed.

  14. Lightweight Radiator Fins for Space Nuclear Power Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase 1 project shall investigate concept radiator fins that incorporate novel carbon materials for improved performance of segmented high temperature...

  15. Curvature-induced stiffening of a fish fin.

    Science.gov (United States)

    Nguyen, Khoi; Yu, Ning; Bandi, Mahesh M; Venkadesan, Madhusudhan; Mandre, Shreyas

    2017-05-01

    How fish modulate their fin stiffness during locomotive manoeuvres remains unknown. We show that changing the fin's curvature modulates its stiffness. Modelling the fin as bendable bony rays held together by a membrane, we deduce that fin curvature is manifested as a misalignment of the principal bending axes between neighbouring rays. An external force causes neighbouring rays to bend and splay apart, and thus stretches the membrane. This coupling between bending the rays and stretching the membrane underlies the increase in stiffness. Using three-dimensional reconstruction of a mackerel (Scomber japonicus) pectoral fin for illustration, we calculate the range of stiffnesses this fin is expected to span by changing curvature. The three-dimensional reconstruction shows that, even in its geometrically flat state, a functional curvature is embedded within the fin microstructure owing to the morphology of individual rays. As the ability of a propulsive surface to transmit force to the surrounding fluid is limited by its stiffness, the fin curvature controls the coupling between the fish and its surrounding fluid. Thereby, our results provide mechanical underpinnings and morphological predictions for the hypothesis that the spanned range of fin stiffnesses correlates with the behaviour and the ecological niche of the fish. © 2017 The Author(s).

  16. Grid Fin Stabilization of the Orion Launch Abort Vehicle

    Science.gov (United States)

    Pruzan, Daniel A.; Mendenhall, Michael R.; Rose, William C.; Schuster, David M.

    2011-01-01

    Wind tunnel tests were conducted by Nielsen Engineering & Research (NEAR) and Rose Engineering & Research (REAR) in conjunction with the NASA Engineering & Safety Center (NESC) on a 6%-scale model of the Orion launch abort vehicle (LAV) configured with four grid fins mounted near the base of the vehicle. The objectives of these tests were to 1) quantify LAV stability augmentation provided by the grid fins from subsonic through supersonic Mach numbers, 2) assess the benefits of swept grid fins versus unswept grid fins on the LAV, 3) determine the effects of the LAV abort motors on grid fin aerodynamics, and 4) generate an aerodynamic database for use in the future application of grid fins to small length-to-diameter ratio vehicles similar to the LAV. The tests were conducted in NASA Ames Research Center's 11x11-foot transonic wind tunnel from Mach 0.5 through Mach 1.3 and in their 9x7-foot supersonic wind tunnel from Mach 1.6 through Mach 2.5. Force- and moment-coefficient data were collected for the complete vehicle and for each individual grid fin as a function of angle of attack and sideslip angle. Tests were conducted with both swept and unswept grid fins with the simulated abort motors (cold jets) off and on. The swept grid fins were designed with a 22.5deg aft sweep angle for both the frame and the internal lattice so that the frontal projection of the swept fins was the same as for the unswept fins. Data from these tests indicate that both unswept and swept grid fins provide significant improvements in pitch stability as compared to the baseline vehicle over the Mach number range investigated. The swept fins typically provide improved stability as compared to the unswept fins, but the performance gap diminished as Mach number was increased. The aerodynamic performance of the fins was not observed to degrade when the abort motors were turned on. Results from these tests indicate that grid fins can be a robust solution for stabilizing the Orion LAV over a wide

  17. Computation of Unsteady Flow Past a Biomimetic Fin

    Institute of Scientific and Technical Information of China (English)

    Hao Liu; Naomi Kato

    2004-01-01

    The unsteady hydrodynamics of a biomimetic fin attached to a cylindrical body has been studied numerically using a computational fluid dynamic (CFD) simulator based on an in-house solver of the Navier-Stokes equations, combined with a recently developed multi-block, overset grid method. The fin-body CFD model is based on a mechanical pectoral fin device, which consists of a cylindrical body and an asymmetric fin and can mimic flapping, rowing and feathering motions of the pectoral fins in fishes. First the multi-block, overset grid method incorporated into the NS solver was verified through an extensive study of unsteady flows past a single fin undergoing rowing and feathering motion. Then unsteady flows past the biomimetic fin-body model undergoing the same motions were computed and compared with the measurements of forces of the mechanical pectoral fin, which shows good agreement in both time-varying and time-averaged hydrodynamic forces. The relationship between force generation and vortex dynamics points to the importance of the match in fin kinematics between power and recovery strokes and implies that an optimal selection of parameters of phase lags between and amplitudes of rowing and feathering motions can improve the performance of labriform propulsion in terms of either maximum force generation or minimum mechanical power.

  18. fgf20 is essential for initiating zebrafish fin regeneration.

    Science.gov (United States)

    Whitehead, Geoffrey G; Makino, Shinji; Lien, Ching-Ling; Keating, Mark T

    2005-12-23

    Epimorphic regeneration requires the presence or creation of pluripotent cells capable of reproducing lost organs. Zebrafish fin regeneration is mediated by the creation of blastema cells. Here, we characterize the devoid of blastema (dob) mutant that fails fin regeneration during initial steps, forms abnormal regeneration epithelium, and does not form blastema. This mutation has no impact on embryonic survival. Dob results from an fgf20a null mutation, Y148S. Fgf20a is expressed during initiation of fin regeneration at the epithelial-mesenchymal boundary and later overlaps with the blastema marker msxb. Thus, fgf20a has a regeneration-specific requirement, initiating fin regeneration, and controlling blastema formation.

  19. Effect of Fin Geometry on Condensation of R134a in a Staggered Bundle of Horizontal Finned Tubes

    Science.gov (United States)

    Honda, Hiroshi; Takata, Nobuo; Takamatsu, Hiroshi; Kim, Jeongsk; Usami, Keiichiro

    Experimental results are presented that show the effect of fin geometry on condensation of refrigerant R134a in a staggered bundle of horizontal fined tubes. Two kinds of conventional low-fin tubes and three kinds of three-dimensional fin tubes were tested. The refrigerant mass velocity ranged from 8 to 23 kg/m2s and the condensation temperature difference from 1.5 to 12 K. In most cases, the highest performance was obtained by one of the three-dimensional fin tubes. In the case of high mass velocity and high film Reynolds number, however, the highest performance was obtained by one of the low-fin tubes. The results were compared with previous experimental results for bundles of smooth tubes and low-fin tubes.

  20. First discovery of a primitive coelacanth fin fills a major gap in the evolution of lobed fins and limbs.

    Science.gov (United States)

    Friedman, Matt; Coates, Michael I; Anderson, Philip

    2007-01-01

    The fossil record provides unique clues about the primitive pattern of lobed fins, the precursors of digit-bearing limbs. Such information is vital for understanding the evolutionary transition from fish fins to tetrapod limbs, and it guides the choice of model systems for investigating the developmental changes underpinning this event. However, the evolutionary preconditions for tetrapod limbs remain unclear. This uncertainty arises from an outstanding gap in our knowledge of early lobed fins: there are no fossil data that record primitive pectoral fin conditions in coelacanths, one of the three major groups of sarcopterygian (lobe-finned) fishes. A new fossil from the Middle-Late Devonian of Wyoming preserves the first and only example of a primitive coelacanth pectoral fin endoskeleton. The strongly asymmetrical skeleton of this fin corroborates the hypothesis that this is the primitive sarcopterygian pattern, and that this pattern persisted in the closest fish-like relatives of land vertebrates. The new material reveals the specializations of paired fins in the modern coelacanth, as well as in living lungfishes. Consequently, the context in which these might be used to investigate evolutionary and developmental relationships between vertebrate fins and limbs is changed. Our data suggest that primitive actinopterygians, rather than living sarcopterygian fishes and their derived appendages, are the most informative comparators for developmental studies seeking to understand the origin of tetrapod limbs.

  1. Magnetic flux pinning in superconductors with hyperbolic-tessellation arrays of pinning sites

    Science.gov (United States)

    Misko, V. R.; Nori, Franco

    2012-05-01

    We study magnetic flux interacting with arrays of pinning sites (APSs) placed on vertices of hyperbolic tessellations (HTs). We show that, due to the gradient in the density of pinning sites, HT APSs are capable of trapping vortices for a broad range of applied magnetic fluxes. Thus, the penetration of magnetic field in HT APSs is essentially different from the usual scenario predicted by the Bean model. We demonstrate that, due to the enhanced asymmetry of the surface barrier for vortex entry and exit, this HT APS could be used as a “capacitor” to store magnetic flux.

  2. Fin o metamorfosis de la escuela

    Directory of Open Access Journals (Sweden)

    José Joaquín Brunner

    1996-10-01

    Full Text Available El autor adhiere a la idea de que la escuela una es una de las matrices de la modernidad por cuanto separa la transmisión cultural de cualquier soporte físico (escritura, radicándola en el propio proceso de escolarización: su gramática consistiría en redes de clasificación del conocimiento, siendo el orden escolar esencialmente un procedimiento; el juego que juega la escuela es el de la obtención de los usos de adquisición del conocimiento. De esta forma el “fin de la escritura” como tecnología predominante del conocimiento, significara el conocimiento de una nueva era de escolarización.

  3. Cherenkov and Scintillation Properties of Cubic Zirconium

    Science.gov (United States)

    Christl, M.J.; Adams, J.H.; Parnell, T.A.; Kuznetsov, E.N.

    2008-01-01

    Cubic zirconium (CZ) is a high index of refraction (n =2.17) material that we have investigated for Cherenkov counter applications. Laboratory and proton accelerator tests of an 18cc sample of CZ show that the expected fast Cherenkov response is accompanied by a longer scintillation component that can be separated by pulse shaping. This presents the possibility of novel particle spectrometers which exploits both properties of CZ. Other high index materials being examined for Cherenkov applications will be discussed. Results from laboratory tests and an accelerator exposure will be presented and a potential application in solar energetic particle instruments will be discussed

  4. Tachyon Vacuum in Cubic Superstring Field Theory

    CERN Document Server

    Erler, Theodore

    2008-01-01

    In this paper we give an exact analytic solution for tachyon condensation in the modified (picture 0) cubic superstring field theory. We prove the absence of cohomology and, crucially, reproduce the correct value for the D-brane tension. The solution is surprising for two reasons: First, the existence of a tachyon vacuum in this theory has not been definitively established in the level expansion. Second, the solution {\\it vanishes} in the GSO$(-)$ sector, implying a ``tachyon vacuum'' solution exists even for a {\\it BPS} D-brane.

  5. Generalized fairing algorithm of parametric cubic splines

    Institute of Scientific and Technical Information of China (English)

    WANG Yuan-jun; CAO Yuan

    2006-01-01

    Kjellander has reported an algorithm for fairing uniform parametric cubic splines. Poliakoff extended Kjellander's algorithm to non-uniform case. However, they merely changed the bad point's position, and neglected the smoothing of tangent at bad point. In this paper, we present a fairing algorithm that both changed point's position and its corresponding tangent vector. The new algorithm possesses the minimum property of energy. We also proved Poliakoff's fairing algorithm is a deduction of our fairing algorithm. Several fairing examples are given in this paper.

  6. Fractal Symmetries: Ungauging the Cubic Code

    CERN Document Server

    Williamson, Dominic J

    2016-01-01

    Gauging is a ubiquitous tool in many-body physics. It allows one to construct highly entangled topological phases of matter from relatively simple phases and to relate certain characteristics of the two. Here we develop a gauging procedure for general submanifold symmetries of Pauli Hamiltonians, including symmetries of fractal type. We show a relation between the pre- and post- gauging models and use this to construct short range entangled phases with fractal like symmetries, one of which is mapped to the cubic code by the gauging.

  7. The Exact Limit of Some Cubic Towers

    DEFF Research Database (Denmark)

    Anbar Meidl, Nurdagül; Beelen, Peter; Nguyen, Nhut

    2016-01-01

    Recently, a new explicit tower of function fields was introduced by Bassa, Beelen, Garcia and Stichtenoth (BBGS). This resulted in currently the best known lower bound for Ihara’s constant in the case of non-prime finite fields. In particular over cubic fields, the tower’s limit is at least as good...... as Zink’s bound; i.e. λ(BBGS/Fq3 ) ≥ 2(q2 - 1)/(q + 2). In this paper, the exact value of λ(BBGS/Fq3 ) is computed. We also settle a question stated by Ihara....

  8. Competing structural instabilities in cubic perovskites

    CERN Document Server

    Vanderbilt, D

    1994-01-01

    We study the antiferrodistortive instability and its interaction with ferroelectricity in cubic perovskite compounds. Our first-principles calculations show that coexistence of both instabilities is very common. We develop a first-principles scheme to study the thermodynamics of these compounds when both instabilities are present, and apply it to SrTiO$_3$. We find that increased pressure enhances the antiferrodistortive instability while suppressing the ferroelectric one. Moreover, the presence of one instability tends to suppress the other. A very rich $P$--$T$ phase diagram results.

  9. Laminar heat transfer characteristics of internally finned tube with sinusoidal wavy fin

    Science.gov (United States)

    Lin, M.; Tian, L.; Wang, Q. W.

    2011-06-01

    Comparative numerical study of laminar heat transfer characteristics of annular tubes with sinusoidal wavy fins has been conducted both experimentally and numerically with Re = 299-1,475. The uniform heat flux is imposed on the tube outside wall surface. Two tube materials (copper and stainless steel) are considered. It is found that the fluid temperature profile is not linear but convex along the flow direction due to the axial heat conduction in tube wall, and the effects of axial heat conduction on the heat transfer decreases with an increase in Reynolds number or decrease in tube wall thermal conductivity. The axial distributions of local Nusselt number could reach periodically fully developed after 3-5 cycles. The convectional data reduction method based on the traditional method should be improved for tube with high thermal conductivity or low Reynolds numbers, Otherwise, the heat transfer performance of internally finned tube may be underestimated.

  10. Fin efficiency analysis of convective straight fins with temperature dependent thermal conductivity using variational iteration method

    Energy Technology Data Exchange (ETDEWEB)

    Coskun, Safa Bozkurt [Department of Civil Engineering, Nigde University, 51245 Nigde (Turkey)], E-mail: sbcoskun@nigde.edu.tr; Atay, Mehmet Tarik [Department of Mathematics, Nigde University, 51245 Nigde (Turkey)

    2008-12-15

    For enhancing heat transfer between primary surface and the environment, utilization of radiating extended surfaces are common. Especially for large temperature differences; variable thermal conductivity has a strong effect on performance of such a surface. In this paper, variational iteration method is used to analyze the efficiency of convective straight fins with temperature dependent thermal conductivity. VIM produces analytical expressions for the solution of nonlinear differential equations. In order to show the effectiveness of variational iteration method (VIM), the results obtained from VIM analysis is compared with available solutions obtained using Adomian decomposition method (ADM) and the results from finite element analysis. This work assures that VIM is a promising method for the efficiency analysis of convective straight fin problems.

  11. Robustness of pinning a general complex dynamical network

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lei, E-mail: lwang@buaa.edu.c [Laboratory of Mathematics, Information and Behavior of the Ministry of Education, Department of Systems and Control, Beihang University, Beijing 100191 (China); Sun Youxian [State Key Laboratory of Industrial Control Technology, Institute of Industrial Process Control, Zhejiang University, Hangzhou 310027 (China)

    2010-04-05

    This Letter studies the robustness problem of pinning a general complex dynamical network toward an assigned synchronous evolution. Several synchronization criteria are presented to guarantee the convergence of the pinning process locally and globally by construction of Lyapunov functions. In particular, if a pinning strategy has been designed for synchronization of a given complex dynamical network, then no matter what uncertainties occur among the pinned nodes, synchronization can still be guaranteed through the pinning. The analytical results show that pinning control has a certain robustness against perturbations on network architecture: adding, deleting and changing the weights of edges. Numerical simulations illustrated by scale-free complex networks verify the theoretical results above-acquired.

  12. A mechanism to pin skyrmions in chiral magnets.

    Science.gov (United States)

    Liu, Ye-Hua; Li, You-Quan

    2013-02-20

    We propose a mechanism to pin skyrmions in chiral magnetic thin films by introducing local maxima of magnetic exchange strength as pinning centers. The local maxima can be realized by engineering the local density of itinerant electrons. The stationary properties and the dynamical pinning and depinning processes of an isolated skyrmion around a pinning center are studied. We carry out numerical simulations of the Landau-Lifshitz-Gilbert (LLG) equation and find a way to control the position of an isolated skyrmion in a pinning center lattice using electric current pulses. The results are verified by a Thiele equation analysis. We also find that the critical current to depin a skyrmion, which is estimated to have order of magnitude 10(7)-10(8) A m(-2), has linear dependence on the pinning strength.

  13. Experimental Validation of Elliptical Fin-Opening Behavior

    Directory of Open Access Journals (Sweden)

    James M. Garner

    2003-01-01

    Full Text Available An effort to improve the performance of ordnance has led to the consideration of the use of folding elliptical fins for projectile stabilization. A second order differential equation was used to model elliptical fin deployment history and accounts for: deployment with respect to the geometric properties of the fin, the variation in fin aerodynamics during deployment, the initial yaw effect on fin opening, and the variation in deployment speed based on changes in projectile spin. This model supports tests conducted at the Transonic Experimental Facility, Aberdeen Proving Ground examining the opening behavior of these uniquely shaped fins. The fins use the centrifugal force from the projectile spin to deploy. During the deployment, the fin aerodynamic forces vary with angle-of-attack changes to the free stream. Model results indicate that projectile spin dominates the initial opening rates and aerodynamics dominate near the fully open state. The model results are examined to explain the observed behaviors, and suggest improvements for later designs.

  14. Dehumidification in greenhouses by condensation on finned pipes

    NARCIS (Netherlands)

    Campen, J.C.; Bot, G.P.A.

    2001-01-01

    In this study, an experimental dehumidifying system for greenhouses is tested. The system uses finned pipes fixed under the gutter of the greenhouse. The pipes are cooled below the dewpoint of the greenhouse air by cold water. The humid air passes the pipe and fins by natural convection and

  15. F-16 Ventral Fin Buffet Alleviation Using Piezoelectric Actuators

    Science.gov (United States)

    2009-09-01

    mode shapes of the test fin, a scanning laser vibrometer using PolyTec R© software version 8.61 was used to measure and analyze the frequency...fin. The PolyTec R© software application recorded and processed the measurements of the laser vibrometer and provided the natural frequencies and mode

  16. Vortex interactions with flapping wings and fins can be unpredictable

    NARCIS (Netherlands)

    Lentink, D.; Heijst, van G.J.F.; Muijres, F.T.; Leeuwen, van J.L.

    2010-01-01

    As they fly or swim, many animals generate a wake of vortices with their flapping fins and wings that reveals the dynamics of their locomotion. Previous studies have shown that the dynamic interaction of vortices in the wake with fins and wings can increase propulsive force. Here, we explore whether

  17. Defective fin regeneration in medaka fish (Oryzias latipes) with hypothyroidism.

    Science.gov (United States)

    Sekimizu, Koshin; Tagawa, Masatomo; Takeda, Hiroyuki

    2007-07-01

    Wild-type medaka are known to have remarkable capabilities of fin, or epimorphic, regeneration. However, a hypothyroid mutant, kamaitachi (kmi), frequently suffers from injury in fins, suggesting an important role of thyroid hormone in fin regeneration. This led us to examine the relationship between thyroid hormone and fin regeneration using medaka as a model. For this, we first set up a medaka experimental system in which the rate of regeneration was statistically analyzed after caudal fin amputation under normal and hypothyroid conditions. As expected, the regeneration of amputated caudal fins was delayed in hypothyroid kmi -/- mutants. We then examined wild-type medaka with thiourea-induced hypothyroidism to evaluate the requirement of thyroid hormone during epimorphic fin regeneration. The results demonstrate that the growth rate of regenerates was much reduced in severely hypothyroid medaka throughout the regeneration period. This reduction in regenerative rate was recovered by exogenous administration of L-thyroxine. The present study is thus the first to report the direct involvement of thyroid hormone in teleost fin regeneration, and provides a basic framework for future molecular and genetic analyses.

  18. FinFET modeling for IC simulation and design

    CERN Document Server

    Hu, Chenming; Lu, Darsen D

    2015-01-01

    This book is the first to explain FinFET modeling for IC simulation and the industry standard - BSIM-CMG - describing the rush in demand for advancing the technology from planar to 3D architecture, as now enabled by the approved industry standard. The book gives a strong foundation on the physics and operation of FinFET, details aspects of the BSIM-CMG model such as surface potential, charge and current calculations, and includes a dedicated chapter on parameter extraction procedures, providing a step-by-step approach for the efficient extraction of model parameters. With this book you will learn: * Why you should use FinFET* The physics and operation of FinFET* Details of the FinFET standard model (BSIM-CMG)* Parameter extraction in BSIM-CMG* FinFET circuit design and simulation * Authored by the lead inventor and developer of FinFET, and developers of the BSIM-CM standard model, providing an experts' insight into the specifications of the standard* The first book on the industry-standard FinFET model - BSIM...

  19. Principles of intramedullary pin and wire fixation.

    Science.gov (United States)

    Howard, P E

    1991-02-01

    Knowledge and experience in the proper use of IM pins, K-wires, and orthopedic wire is a valuable asset to the veterinarian's ability to successfully repair a variety of long bone fractures. Most long bone fractures are amenable to repair with this form of fixation. When the principles of application are violated or the implants are used when contraindicated, complications often occur. Proper use of these implants results in the successful management of complex fractures to the satisfaction of both the animal owner and the veterinarian (Fig 10).

  20. Controlling Flow Turbulence Using Local Pinning Feedback

    Institute of Scientific and Technical Information of China (English)

    TANG Guo-Ning; HU Gang

    2006-01-01

    Flow turbulence control in two-dimensional Navier-Stokes equation is considered.By applying local pinning control only to a sjngle component of flow velocity field,the flow turbulence can be controlled to desirable targets.It is found that with certain number of controllers there exist an optimal control strength at which control error takes minimum value,and larger and smaller control strengths give worse control efficiency.The phvsical mechanism underlying these strange control results is analysed based on the interactions between different types of modes.

  1. Optimum Prestress of Tanks with Pinned Base

    DEFF Research Database (Denmark)

    Brøndum-Nielsen, Troels

    1998-01-01

    Amin Ghali and Eleanor Elliott presented in their paper an interesting suggestion for prestressing of circular tanks without sliding joints. For many prestressed tanks the following construction procedure is adopted:In order to ensure compressive hoop forces in the wall near the base, the wall...... is allowed to slide freely in the radial direction during tensioning (free base).After tensioning such displacements are prevented (pinned base). The present paper addresses the problem of prestress of such tanks.Keywords: circular prestressing; creep properties; prestressed concrete; redistribution...... of stress; stress relaxation; tanks....

  2. Effective Heat Transfer Enhancement in Finned Tube Heat Exchanger with Different Fin Profiles

    Directory of Open Access Journals (Sweden)

    J.A.Livingston1 , P. Selvakumar2

    2013-04-01

    Full Text Available During cross flow in a heat exchanger, heat transfer in the front portion of the tube is more compared to back portion of the tube. This is due to less formation of vortices at the backside of the tube. For uniform heat transfer to take place throughout the tube, it is necessary to increase the vortex formation at the rear side of the tube. The aim of this study is to explore the possibilities of improving the flow structure and thereby increasing uniform heat transfer around the tubes by introducing special type of fin arrangement over the tubes. The effect of shape and orientation of the fin on vortex generation and respective heat transfers are studied numerically. It have been identified that by introducing special type of fin arrangement over the tube there is a possibility for increase the vortex formation at the rear portion of the tube, which significantly leads to creation of uniform heat transfer all around the tube.

  3. Heat transfer to finned tubes exposed to hot waste gas

    Energy Technology Data Exchange (ETDEWEB)

    Scholand, E.; Kremer, H.

    1975-05-01

    Transfer of heat by forced convection to finned tubes, particularly to those with an elliptical center pipe, is described. These pipes are used in gas-fired water heaters, boilers, and heat exchangers. Finned tubes in a test tunnel were exposed to a stream of waste gas from a gas/air mixture at different Reynolds numbers. Mathematical relationships showing the dependence of the Nusselt number on the Reynolds number and on the geometry of the tubes were derived. The single pipe showed a significant drop in the heat-transfer coefficient as the gap between fins became closer. The results of the measurement of heat transfer by forced convection to finned tubes were expressed in a standard form for all tubes. The same heat transfer law can be applied to electrically heated finned tubes exposed to a stream of cooling air.

  4. Research on swimming by undulatory long dorsal fin propulsion

    Institute of Scientific and Technical Information of China (English)

    WANG Gnangming; SHEN Lincheng; WU Yonghui

    2007-01-01

    The kinematics of steady forward swimming of Gymnarchus niloticus is described. The geometric features of the body and locomotive characteristic and parameters of the flexible dorsal fin are discussed. On the basis of observation and experimental data, a simplified kinematic model on loco- motion of the undulatory long dorsal fin propulsion is pro- moted. The hydromechanical performances of the undulatory long dorsal fin propeller of G. Niloticus are estimated with the large-amplitude elongated-body theory. The hydromechani- cal efficiency of the undulatory long dorsal fin system ranged from 81.664% to 86.420% over a speed range of 0.728- 0.985 length·s-1. It is suggested that the undulatory long dorsal fin propulsion is an adaptation to swimming with high hydromechanical efficiency.

  5. Numerical and Experimental Research on Modular Oscillating Fin

    Institute of Scientific and Technical Information of China (English)

    Yong-hua Zhang; Yan Song; Jie Yang; K. H. Low

    2008-01-01

    Fishes are famous for their ability to position themselves accurately even in turbulent flows. This ability is the result of the coordinated movement of fins which extend from the body. We have embarked on a research program designed to develop an agile and high efficient biologically inspired robotic fish based on the performance of hybrid mechanical fins. To accomplish this goal, a mechanical ray-like fin actuated by Shape Memory Alloy (SMA) is developed, which can realize both oscillatory locomotion and undulatory locomotion. We first give a brief introduction on the mechanical structure of our fin and then carr yout theoretic analysis on force generation. Detailed information of these theoretical results is later revealed by Computational Fluid Dynamic (CFD), and is final validated by experiments. This robotic fin has potential application as a propulsor for future underwater vehicles in addition to being a valuable scientific instrument.

  6. Rheological properties of Cubic colloidal suspensions

    Science.gov (United States)

    Boromand, Arman; Maia, Joao

    2016-11-01

    Colloidal and non-colloidal suspensions are ubiquitous in many industrial application. There are numerous studies on these systems to understand and relate their complex rheological properties to their microstructural evolution under deformation. Although most of the experimental and simulation studies are centered on spherical particles, in most of the industrial applications the geometry of the colloidal particles deviate from the simple hard sphere and more complex geometries exist. Recent advances in microfabrication paved the way to fabricate colloidal particles with complex geometries for applications in different areas such as drug delivery where the fundamental understanding of their dynamics has remained unexplored. In this study, using dissipative particle dynamics, we investigate the rheological properties of cubic (superball) particles which are modeled as the cluster of core-modified DPD particles. Explicit representation of solvent particles in the DPD scheme will conserve the full hydrodynamic interactions between colloidal particles. Rheological properties of these cubic suspensions are investigated in the dilute and semi-dilute regimes. The Einstein and Huggins coefficients for these particles with different superball exponent will be calculate which represent the effect of single particle's geometry and multibody interactions on viscosity, respectively. The response of these suspensions is investigated under simple shear and oscillatory shear where it is shown that under oscillation these particles tend to form crystalline structure giving rise to stronger shear-thinning behavior recently measured experimentally.

  7. Development of 3D pseudo pin-by-pin calculation methodology in ANC

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, B.; Mayhue, L.; Huria, H.; Ivanov, B. [Westinghouse Electric Company LLC, 1000 Westinghouse Drive, Cranberry, PA 16066 (United States)

    2012-07-01

    Advanced cores and fuel assembly designs have been developed to improve operational flexibility, economic performance and further enhance safety features of nuclear power plants. The simulation of these new designs, along with strong heterogeneous fuel loading, have brought new challenges to the reactor physics methodologies currently employed in the industrial codes for core analyses. Control rod insertion during normal operation is one operational feature in the AP1000{sup R} plant of Westinghouse next generation Pressurized Water Reactor (PWR) design. This design improves its operational flexibility and efficiency but significantly challenges the conventional reactor physics methods, especially in pin power calculations. The mixture loading of fuel assemblies with significant neutron spectrums causes a strong interaction between different fuel assembly types that is not fully captured with the current core design codes. To overcome the weaknesses of the conventional methods, Westinghouse has developed a state-of-the-art 3D Pin-by-Pin Calculation Methodology (P3C) and successfully implemented in the Westinghouse core design code ANC. The new methodology has been qualified and licensed for pin power prediction. The 3D P3C methodology along with its application and validation will be discussed in the paper. (authors)

  8. The pin pixel detector--X-ray imaging

    CERN Document Server

    Bateman, J E; Derbyshire, G E; Duxbury, D M; Marsh, A S; Simmons, J E; Stephenson, R

    2002-01-01

    The development and testing of a soft X-ray gas pixel detector, which uses connector pins for the anodes is reported. Based on a commercial 100 pin connector block, a prototype detector of aperture 25.4 mm centre dot 25.4 mm can be economically fabricated. The individual pin anodes all show the expected characteristics of small gas detectors capable of counting rates reaching 1 MHz per pin. A 2-dimensional resistive divide readout system has been developed to permit the imaging properties of the detector to be explored in advance of true pixel readout electronics.

  9. 327 to 324 Pin tube shipment quality management process plan

    Energy Technology Data Exchange (ETDEWEB)

    HAM, J.E.

    1998-11-05

    The B and W Hanford Company's (BWHC) 327 Facility, in the 300 Area of the Hanford Site, is preparing to ship five Pin Tubes to the 324 Facility for storage and eventual disposition. The Pin Tubes consist of legacy fuel pin pieces and drillings. They will be over-packed in new Pin Tubes and transported to 324 in three shipments. Once received at 324, two of the shipments will be combined for storage as a fissionable material batch, and the other shipment will be added to an existing batch.

  10. [Ingestion of an open safety pin--challenging treatment].

    Science.gov (United States)

    DeRowe, Ari; Fishman, Gadi; Avni, Hadas; Reider, Ivgeny; Ogorek, Daniel

    2003-11-01

    A 9 month old girl at the emergency room appeared with an acute onset of restlessness, drooling and suspected foreign body ingestion. An X-Ray revealed an open safety pin in the child's upper aero-digestive tract. The source of the safety pin was a "Hamsah" good luck charm that was attached to her bed. Open safety pins in the aero-digestive tract are difficult to manage and great care must be taken during removal to prevent further injury. Parents should be counseled regarding the presence of safety pins in the child's surroundings in order to prevent such hazards.

  11. Changing the flux flow state in weak pinning superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Leo, A., E-mail: antoleo@sa.infn.it [Physics Department E.R. Caianiello, University of Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy); CNR-SPIN Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy); Grimaldi, G. [CNR-SPIN Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy); Nigro, A. [Physics Department E.R. Caianiello, University of Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy); CNR-SPIN Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy); Bruno, E.; Priolo, F. [Matis IMM-CNR and Physics-Astronomy Department, Catania University, CT 95123 (Italy); Pace, S. [Physics Department E.R. Caianiello, University of Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy); CNR-SPIN Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy)

    2014-08-15

    Highlights: • We analyzed the effect of light ion irradiation on weak pinning superconductors. • We found the light ion irradiation has a strong impact on current currying stability. • We compared the results to the ones of the case of moderate strong pinning materials. - Abstract: The current carrying dissipative state well above the critical current it is known to be related to the pinning properties of the material and to the microscopic mechanisms of vortex dynamics. Moreover, it has been demonstrated that in low temperature superconducting films exhibiting moderately strong pinning the light ion irradiation has the effect of changing the distribution of the pinning centers without changing their pinning strength and this results into an increase of current stability in the flux flow state. Here we present the results of light ion irradiation on weak pinning superconducting films focusing on the influence of pinning properties of the material in the flux flow state. We realize that the possibility to switch to low dissipations by changing weak pinning is not straightforward.

  12. Evaluating the Fin-ray Trajectory Tracking of Bio-inspired Robotic Undulating Fins via an Experimental-numerical Approach

    Directory of Open Access Journals (Sweden)

    Xiaojia Xiang

    2014-07-01

    Full Text Available In the past decade, biomimetic undulating fin propulsion has been one of the main topics considered by scientists and researchers in the field of robotic fish. This technology is inspired by the biological wave-like propulsion of ribbon-finned fish. The swimming modes have aquatic application potentials with greater manoeuvrability, less detectable noise or wake and better efficiency at low speeds. The present work concentrates on the evaluation of fin-ray trajectory tracking of biorobotic undulating fins at the levels of kinematics and hydrodynamics by using an experimental-numerical approach. Firstly, fin-ray tracking inconsistence between the desired and actual undulating trajectories is embodied with experimental data of the fin prototype. Next, the dynamics' nonlinearity is numerically and analytically unveiled by using the computational fluid dynamics (CFD method, from the viewpoint of vortex shedding and the hydro-effect. The evaluation of fin-ray tracking performance creates a good basis for control design to improve the fin-ray undulation of prototypes.

  13. Pin-ups: pictures that fascinate and seduce Pin-ups: fotografias que encantam e seduzem

    Directory of Open Access Journals (Sweden)

    Maria Irene Pellegrino de Oliveira Souza

    2010-08-01

    Full Text Available Starting from photography studies, social anthropology and body visual, this article approaches the social construction of the feminine image through times. It narrates the history of erotic pinups photography and its fetishist elements. Pin-ups have aroused in the end of 19tcentury and it represents the free spirit of women. Slowly, it provokes the breakup of sensuality and sexuality feminine traditionalism. The article also discusses women’s sensuality as a desire object. The pin-ups sensual demure – with a mystery atmosphere – stimulated the eroticism at the beginning of the 20 century and, until nowadays, it provokes admiration, sigh and desire. Com base em estudos sobre fotografia, antropologia social e visual do corpo, este artigo aborda a imagem feminina socialmente construída através dos tempos. Narra o histórico da fotografia erótica de pin-ups e seus elementos fetichistas. As pin-ups surgiram no final do século XIX e representaram o espírito “livre” das mulheres. Sutilmente, incitavam o rompimento do tradicionalismo da época quanto à sensualidade e sexualidade feminina. O artigo aborda também a sensualidade feminina como objeto de desejo. O recato sensual das pin-ups – com ar de mistério – alavancou o erotismo no início do século XX e, até os dias atuais, provoca admiração, suspiros e desejos.

  14. Lightning Pin Injection Testing on MOSFETS

    Science.gov (United States)

    Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.; Koppen, Sandra V.; Mielnik, John J.; Vaughan, Roger K.; Wysocki, Philip F.; Celaya, Jose R.; Saha, Sankalita

    2009-01-01

    Lightning transients were pin-injected into metal-oxide-semiconductor field-effect transistors (MOSFETs) to induce fault modes. This report documents the test process and results, and provides a basis for subsequent lightning tests. MOSFETs may be present in DC-DC power supplies and electromechanical actuator circuits that may be used on board aircraft. Results show that unprotected MOSFET Gates are susceptible to failure, even when installed in systems in well-shielded and partial-shielded locations. MOSFET Drains and Sources are significantly less susceptible. Device impedance decreased (current increased) after every failure. Such a failure mode may lead to cascading failures, as the damaged MOSFET may allow excessive current to flow through other circuitry. Preliminary assessments on a MOSFET subjected to 20-stroke pin-injection testing demonstrate that Breakdown Voltage, Leakage Current and Threshold Voltage characteristics show damage, while the device continues to meet manufacturer performance specifications. The purpose of this research is to develop validated tools, technologies, and techniques for automated detection, diagnosis and prognosis that enable mitigation of adverse events during flight, such as from lightning transients; and to understand the interplay between lightning-induced surges and aging (i.e. humidity, vibration thermal stress, etc.) on component degradation.

  15. Optimizing Dynamical Network Structure for Pinning Control

    Science.gov (United States)

    Orouskhani, Yasin; Jalili, Mahdi; Yu, Xinghuo

    2016-04-01

    Controlling dynamics of a network from any initial state to a final desired state has many applications in different disciplines from engineering to biology and social sciences. In this work, we optimize the network structure for pinning control. The problem is formulated as four optimization tasks: i) optimizing the locations of driver nodes, ii) optimizing the feedback gains, iii) optimizing simultaneously the locations of driver nodes and feedback gains, and iv) optimizing the connection weights. A newly developed population-based optimization technique (cat swarm optimization) is used as the optimization method. In order to verify the methods, we use both real-world networks, and model scale-free and small-world networks. Extensive simulation results show that the optimal placement of driver nodes significantly outperforms heuristic methods including placing drivers based on various centrality measures (degree, betweenness, closeness and clustering coefficient). The pinning controllability is further improved by optimizing the feedback gains. We also show that one can significantly improve the controllability by optimizing the connection weights.

  16. Medio-lateral entry pin versus lateral entry pin for displaced pediatric supracondylar fractures: A comparative, prospective study

    Directory of Open Access Journals (Sweden)

    Manoj Kandel

    2016-01-01

    Full Text Available Background & Objectives: Supracondylar fracture is one of the commonest fractures in children. Although the technique of pinning is controversial, percutaneous medio-lateral entry pinning is theoretically considered more stable biomechanical construct. The drawback of this method is injury to ulnar nerve which is not encountered in only lateral entry pinning.Materials & Methods: This was a prospective, comparative and observational study done in 60 patients which was alternately divided into two groups. The first group (A underwent medio-lateral entry pinning and the second group (B underwent lateral entry pinning. They were followed for 24 weeks and the outcome was assessed using Flynn’s criteria.Results: At twenty-four weeks, the mean loss of range of motion of elbow in medio-lateral pinning group was 3.70 degrees (SD±1.93 and that in lateral pinning group was 4.23 degrees (SD ±1.38. The mean loss in carrying angle at twenty-four weeks in medio-lateral group was 2.93 degrees (SD±2.19 and that in lateral group was 4.17 (SD±2.24. There were 2 (6.67% cases of iatrogenic ulnar nerve injury in medio-lateral pinning group. Out of thirty patients, in medio-lateral pinning group, 25 had excellent results, 5 had good results and none had fair or poor results. While out of 30 patients in lateral pinning group, 23 had excellent results, 7 had good results and none had fair or poor results.Conclusion: There is no significant difference in outcome in terms of loss of carrying angle and range of motion between the medio-lateral pinning group and the lateral pinning group at the end of 6 months.Journal of College of Medical Sciences-Nepal, Vol.11(4 2015: 28-31

  17. All unitary cubic curvature gravities in D dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Sisman, Tahsin Cagri; Guellue, Ibrahim; Tekin, Bayram, E-mail: sisman@metu.edu.tr, E-mail: e075555@metu.edu.tr, E-mail: btekin@metu.edu.tr [Department of Physics, Middle East Technical University, 06531 Ankara (Turkey)

    2011-10-07

    We construct all the unitary cubic curvature gravity theories built on the contractions of the Riemann tensor in D-dimensional (anti)-de Sitter spacetimes. Our construction is based on finding the equivalent quadratic action for the general cubic curvature theory and imposing ghost and tachyon freedom, which greatly simplifies the highly complicated problem of finding the propagator of cubic curvature theories in constant curvature backgrounds. To carry out the procedure we have also classified all the unitary quadratic models. We use our general results to study the recently found cubic curvature theories using different techniques and the string generated cubic curvature gravity model. We also study the scattering in critical gravity and give its cubic curvature extensions.

  18. Nanoengineering of Flux Pinning Sites in High-Tc Superconductors

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Volume pinning forces were determined for a variety of bulk high-Tcsuperconductors of the 123-type from magnetization measurements. By means of scaling of the pinning forces, the acting pinning mechanisms in various temperature ranges were identified. The Nd-based superconductors and some YBCO crystalsexhibited a dominating pinning of the δTc-type (i.e., small, superconducting pinning sites). In contrast to this, the addition of insulating 211 particles provided pinning of the δl-type; providing effective pinning in the entire temperature range acting as a "background" pinning mechanism for the peak effect. Due to the small coherence lengths of the high-Tc compounds, effective pinning sites are defects or particles of nanometer size relative to ξ3. Integral magnetic measurements of the magnetization as a function of temperature in large applied magnetic fields (up to 7 T) revealed that practically all high-Tc compounds were spatially inhomogeneous, which could be caused byoxygen deficiency (YBCO), solid solutions of Nd/Ba (NdBCO and other light rare earth compounds), intergrowths (Bi-based superconductors), and doping by pair-breaking dopants like Zn, Pr. This implies that the superconducting sample consists of stronger and weaker superconducting areas, coupled together. In large appliedfields, this coupling gets broken and the magnetization versus temperature curves revealed more than one superconducting transition. In contrast, irradiation experiments by neutrons, protons, and heavy-ions enabled the artificial introduction of very effective pinning sites into the high-Tc superconductors, thus creating a large variety of different observations using magnetic data. From all these observations, we construct a pinning diagram for bulk high-Tc superconductors explaining many features observed in high-Tc samples.

  19. Experimental Investigation of Heat Transfer and Pressure Drop Characteristics of H-type Finned Tube Banks

    OpenAIRE

    2014-01-01

    H-type finned tube heat exchanger elements maintain a high capacity for heat transfer, possess superior self-cleaning properties and retain the ability to effect flue gas waste heat recovery in boiler renovations. In this paper, the heat transfer and pressure drop characteristics of H-type finned tube banks are studied via an experimental open high-temperature wind tunnel system. The effects of fin width, fin height, fin pitch and air velocity on fin efficiency, convective heat transfer coe...

  20. Film condensation of HCFC-123 on in-line bundles of horizontal finned tubes. Effect of fin geometry. Suihei fin tsuki kan no gobanme kangun ni okeru HCFC-123 no gyoshuku. Fin keijo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Takamatsu, H.; Takada, N. (Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study); Kim, K. (Kyushu University, Fukuoka (Japan)); Ishikawa, Y. (Otsuka Pharmaceutical Co. Ltd., Tokyo (Japan))

    1994-06-25

    Theoretical analysis and experiments were carried out in regard to the condensation of HCFC-123 vapor on a horizontal finned tube. The previous paper described the theoretical analysis on the film condensation in a tube nest with low-fins. In this study, approximate expressions of heat transfer coefficient for a newly proposed high-performance finned tubes are suggested and compared with the experimental results. In the test, HCFC-123 vapor was flowed from the upper part of the tube nest arranged in squares of 3 rows and 15 layers (tube pitch: 22mm), and was condensed on the tube surface. The liquid film formation was observed, and the heat transfer properties were measured. Two kinds of conventional low-fin tubes and two kinds of finned tubes of which shape is similar to the newly proposed ones were tested. One of the new finned tubes showed the highest heat transfer performance, which was about 85% higher than that of the conventional low-fin (26 fpi) tube. The theoretical model for condensation in the previous paper was correspondent with the experimental data at low vapor speed and low condensate inundation rate. 14 refs., 14 figs., 4 tabs.

  1. Cubic meter volume optical coherence tomography

    Science.gov (United States)

    WANG, ZHAO; POTSAID, BENJAMIN; CHEN, LONG; DOERR, CHRIS; LEE, HSIANG-CHIEH; NIELSON, TORBEN; JAYARAMAN, VIJAYSEKHAR; CABLE, ALEX E.; SWANSON, ERIC; FUJIMOTO, JAMES G.

    2017-01-01

    Optical coherence tomography (OCT) is a powerful three-dimensional (3D) imaging modality with micrometer-scale axial resolution and up to multi-GigaVoxel/s imaging speed. However, the imaging range of high-speed OCT has been limited. Here, we report 3D OCT over cubic meter volumes using a long coherence length, 1310 nm vertical-cavity surface-emitting laser and silicon photonic integrated circuit dual-quadrature receiver technology combined with enhanced signal processing. We achieved 15 µm depth resolution for tomographic imaging at a 100 kHz axial scan rate over a 1.5 m range. We show 3D macroscopic imaging examples of a human mannequin, bicycle, machine shop gauge blocks, and a human skull/brain model. High-bandwidth, meter-range OCT demonstrates new capabilities that promise to enable a wide range of biomedical, scientific, industrial, and research applications. PMID:28239628

  2. Black holes in Einsteinian cubic gravity

    CERN Document Server

    Hennigar, Robie A

    2016-01-01

    Using numerical and perturbative methods, we construct the first examples of black hole solutions in Einsteinian cubic gravity and study their thermodynamics. Focusing first on four dimensional solutions, we show that these black holes have a novel equation of state in which the pressure is a quadratic function of the temperature. Despite this, they undergo a first order phase transition with associated van der Waals behaviour. We then construct perturbative solutions for general $D \\ge 5$ and study the properties of these solutions for $D=5$ and $D=6$ in particular. We find novel examples of zeroth order phase transitions and find super-entropic behaviour over a large portion of the parameter space. We analyse the specific heat, determining that the black holes are thermodynamically stable over large regions of parameter space.

  3. Triangulation of cubic panorama for view synthesis.

    Science.gov (United States)

    Zhang, Chunxiao; Zhao, Yan; Wu, Falin

    2011-08-01

    An unstructured triangulation approach, new to our knowledge, is proposed to apply triangular meshes for representing and rendering a scene on a cubic panorama (CP). It sophisticatedly converts a complicated three-dimensional triangulation into a simple three-step triangulation. First, a two-dimensional Delaunay triangulation is individually carried out on each face. Second, an improved polygonal triangulation is implemented in the intermediate regions of each of two faces. Third, a cobweblike triangulation is designed for the remaining intermediate regions after unfolding four faces to the top/bottom face. Since the last two steps well solve the boundary problem arising from cube edges, the triangulation with irregular-distribution feature points is implemented in a CP as a whole. The triangular meshes can be warped from multiple reference CPs onto an arbitrary viewpoint by face-to-face homography transformations. The experiments indicate that the proposed triangulation approach provides a good modeling for the scene with photorealistic rendered CPs.

  4. Black holes in a cubic Galileon universe

    CERN Document Server

    Babichev, Eugeny; Lehébel, Antoine; Moskalets, Tetiana

    2016-01-01

    We find and study the properties of black hole solutions for a subclass of Horndeski theory including the cubic Galileon term. The theory under study has shift symmetry but not reflection symmetry for the scalar field. The Galileon is assumed to have linear time dependence characterized by a velocity parameter. We give analytic 3-dimensional solutions that are akin to the BTZ solutions but with a non-trivial scalar field that modifies the effective cosmological constant. We then study the 4-dimensional asymptotically flat and de Sitter solutions. The latter present three different branches according to their effective cosmological constant. For two of these branches, we find families of black hole solutions, parametrized by the velocity of the scalar field. These spherically symmetric solutions, obtained numerically, are different from GR solutions close to the black hole event horizon, while they have the same de-Sitter asymptotic behavior. The velocity parameter represents black hole primary hair.

  5. Finite element differential forms on cubical meshes

    CERN Document Server

    Arnold, Douglas N

    2012-01-01

    We develop a family of finite element spaces of differential forms defined on cubical meshes in any number of dimensions. The family contains elements of all polynomial degrees and all form degrees. In two dimensions, these include the serendipity finite elements and the rectangular BDM elements. In three dimensions they include a recent generalization of the serendipity spaces, and new H(curl) and H(div) finite element spaces. Spaces in the family can be combined to give finite element subcomplexes of the de Rham complex which satisfy the basic hypotheses of the finite element exterior calculus, and hence can be used for stable discretization of a variety of problems. The construction and properties of the spaces are established in a uniform manner using finite element exterior calculus.

  6. Capturing dynamic cation hopping in cubic pyrochlores

    Science.gov (United States)

    Brooks Hinojosa, Beverly; Asthagiri, Aravind; Nino, Juan C.

    2011-08-01

    In direct contrast to recent reports, density functional theory predicts that the most stable structure of Bi2Ti2O7 pyrochlore is a cubic Fd3¯m space group by accounting for atomic displacements. The displaced Bi occupies the 96g(x,x,z) Wyckoff position with six equivalent sites, which create multiple local minima. Using nudged elastic band method, the transition states of Bi cation hopping between equivalent minima were investigated and an energy barrier between 0.11 and 0.21 eV was determined. Energy barriers associated with the motion of Bi between equivalent sites within the 96g Wyckoff position suggest the presence of dielectric relaxation in Bi2Ti2O7.

  7. On the plane-wave cubic vertex

    CERN Document Server

    Lucietti, J; Sinha, A K; Lucietti, James; Schäfer-Nameki, Sakura; Sinha, Aninda

    2004-01-01

    The exact bosonic Neumann matrices of the cubic vertex in plane-wave light-cone string field theory are derived using the contour integration techniques developed in our earlier paper. This simplifies the original derivation of the vertex. In particular, the Neumann matrices are written in terms of \\mu-deformed Gamma-functions, thus casting them into a form that elegantly generalizes the well-known flat-space solution. The asymptotics of the \\mu-deformed Gamma-functions allow one to determine the large-\\mu behaviour of the Neumann matrices including exponential corrections. We provide an explicit expression for the first exponential correction and make a conjecture for the subsequent exponential correction terms.

  8. Polarization conversion in cubic Raman crystals

    Science.gov (United States)

    McKay, Aaron; Sabella, Alexander; Mildren, Richard P.

    2017-01-01

    Nonlinear conversion of unpolarized beams to lower frequencies is generally inefficient in c(2) materials, as it is challenging to achieve phase-matching for input ordinary and extraordinary beams simultaneously in the normal dispersion regime. Here, we show that cubic Raman crystals having doubly and triply degenerate (E and F type) modes provide a method for efficient nonlinear frequency downconversion of an unpolarized beam and yield a linearly polarized output state. Using Mueller calculus, optimal crystal directions for such polarization conversion are determined. Using diamond, an example of an F-class Raman crystal, we have verified that such conversion is possible with near quantum-defect-limited slope efficiency and a linear polarization contrast of more than 23.9 dB. PMID:28169327

  9. On the Stability of Cubic Galileon Accretion

    CERN Document Server

    Bergliaffa, Santiago P E

    2016-01-01

    We examine the stability of steady-state galileon accretion for the case of a Schwarzshild black hole. Considering the galileon action up to the cubic term in a static and spherically symmetric background we obtain the general solution for the equation of motion which is divided in two branches. By perturbing this solution we define an effective metric which determines the propagation of fluctuations. In this general picture we establish the position of the sonic horizon together with the matching condition of the two branches on it. Restricting to the case of a Schwarzschild background, we show, via the analysis of the energy of the perturbations and its time derivative, that the accreting field is linearly stable.

  10. FinTech Market Development Perspectives

    Directory of Open Access Journals (Sweden)

    Kalmykova Ekaterina

    2016-01-01

    Full Text Available Fast development of technologies has led to emergence of the new market – FinTech – which is very attractive for investors today. By now this market has a great number of different concepts: P2P-crediting, E-wallets, Bitcoins, mPOS-acquiring, T-commerce, mobile banks, etc. Many of these tools have already heavily entered our ordinary life. People can obtain any credits through special services on the Internet from other users without participation of banks, pay by credit card using mobile devices, and get information about expenses and incomes according to the card anywhere in the world. Users do not need to go to banks anymore and to spend their time for credit arrangements, currency exchange, to look for ATMs to remove cash. Purchases on the Internet can be paid not only in rubles, but also in new digital currency. These tools make life easier, however, they pose a serious threat for banks. Now, bank institutions should create more convenient and utility services for the clients to keep clients. Therefore, bank and credit systems start to change actively.

  11. The hydrodynamics of ribbon-fin propulsion during impulsive motion.

    Science.gov (United States)

    Shirgaonkar, Anup A; Curet, Oscar M; Patankar, Neelesh A; Maciver, Malcolm A

    2008-11-01

    Weakly electric fish are extraordinarily maneuverable swimmers, able to swim as easily forward as backward and rapidly switch swim direction, among other maneuvers. The primary propulsor of gymnotid electric fish is an elongated ribbon-like anal fin. To understand the mechanical basis of their maneuverability, we examine the hydrodynamics of a non-translating ribbon fin in stationary water using computational fluid dynamics and digital particle image velocimetry (DPIV) of the flow fields around a robotic ribbon fin. Computed forces are compared with drag measurements from towing a cast of the fish and with thrust estimates for measured swim-direction reversals. We idealize the movement of the fin as a traveling sinusoidal wave, and derive scaling relationships for how thrust varies with the wavelength, frequency, amplitude of the traveling wave and fin height. We compare these scaling relationships with prior theoretical work. The primary mechanism of thrust production is the generation of a streamwise central jet and the associated attached vortex rings. Under certain traveling wave regimes, the ribbon fin also generates a heave force, which pushes the body up in the body-fixed frame. In one such regime, we show that as the number of waves along the fin decreases to approximately two-thirds, the heave force surpasses the surge force. This switch from undulatory parallel thrust to oscillatory normal thrust may be important in understanding how the orientation of median fins may vary with fin length and number of waves along them. Our results will be useful for understanding the neural basis of control in the weakly electric knifefish as well as for engineering bio-inspired vehicles with undulatory thrusters.

  12. Water flow and fin shape polymorphism in coral reef fishes.

    Science.gov (United States)

    Binning, Sandra A; Roche, Dominique G

    2015-03-01

    Water flow gradients have been linked to phenotypic differences and swimming performance across a variety of fish assemblages. However, the extent to which water motion shapes patterns of phenotypic divergence within species remains unknown. We tested the generality of the functional relationship between swimming morphology and water flow by exploring the extent of fin and body shape polymorphism in 12 widespread species from three families (Acanthuridae, Labridae, Pomacentridae) of pectoral-fin swimming (labriform) fishes living across localized wave exposure gradients. The pectoral fin shape of Labridae and Acanthuridae species was strongly related to wave exposure: individuals with more tapered, higher aspect ratio (AR) fins were found on windward reef crests, whereas individuals with rounder, lower AR fins were found on leeward, sheltered reefs. Three of seven Pomacentridae species showed similar trends, and pectoral fin shape was also strongly related to wave exposure in pomacentrids when fin aspect ratios of three species were compared across flow habitats at very small spatial scales (back lagoon). Unlike fin shape, there were no intraspecific differences in fish body fineless ratio across habitats or depths. Contrary to our predictions, there was no pattern relating species' abundances to polymorphism across habitats (i.e., abundance was not higher at sites where morphology is better adapted to the environment). This suggests that there are behavioral and/or physiological mechanisms enabling some species to persist across flow habitats in the absence of morphological differences. We suggest that functional relationships between swimming morphology and water flow not only structure species assemblages, but are yet another important variable contributing to phenotypic differences within species. The close links between fin shape polymorphism and local water flow conditions appear to be important for understanding species' distributions as well as patterns of

  13. Low pressure growth of cubic boron nitride films

    Science.gov (United States)

    Ong, Tiong P. (Inventor); Shing, Yuh-Han (Inventor)

    1997-01-01

    A method for forming thin films of cubic boron nitride on substrates at low pressures and temperatures. A substrate is first coated with polycrystalline diamond to provide a uniform surface upon which cubic boron nitride can be deposited by chemical vapor deposition. The cubic boron nitride film is useful as a substitute for diamond coatings for a variety of applications in which diamond is not suitable. any tetragonal or hexagonal boron nitride. The cubic boron nitride produced in accordance with the preceding example is particularly well-suited for use as a coating for ultra hard tool bits and abrasives, especially those intended to use in cutting or otherwise fabricating iron.

  14. Shape preserving rational cubic spline for positive and convex data

    Directory of Open Access Journals (Sweden)

    Malik Zawwar Hussain

    2011-11-01

    Full Text Available In this paper, the problem of shape preserving C2 rational cubic spline has been proposed. The shapes of the positive and convex data are under discussion of the proposed spline solutions. A C2 rational cubic function with two families of free parameters has been introduced to attain the C2 positive curves from positive data and C2 convex curves from convex data. Simple data dependent constraints are derived on free parameters in the description of rational cubic function to obtain the desired shape of the data. The rational cubic schemes have unique representations.

  15. Robotic Pectoral Fin Thrust Vectoring Using Weighted Gait Combinations

    Directory of Open Access Journals (Sweden)

    John S. Palmisano

    2012-01-01

    Full Text Available A method was devised to vector propulsion of a robotic pectoral fin by means of actively controlling fin surface curvature. Separate flapping fin gaits were designed to maximize thrust for each of three different thrust vectors: forward, reverse, and lift. By using weighted combinations of these three pre-determined main gaits, new intermediate hybrid gaits for any desired propulsion vector can be created with smooth transitioning between these gaits. This weighted gait combination (WGC method is applicable to other difficult-to-model actuators. Both 3D unsteady computational fluid dynamics (CFD and experimental results are presented.

  16. Effect of vapor velocity during condensation on horizontal finned tubes

    OpenAIRE

    Hopkins, Charles Louis III

    1988-01-01

    Approved for public release; distribution is unlimited Heat-transfer measurements were made for condensation of R-113 and steam on a smooth tube and on three finned tubes with rectangular shape fins. These tubes had a fin height and width of 1.0 mm and spacings of 0.25, 1.5, and 4.0 mm (tubes A, B, and C respectively) . Data were taken by increasing the vapor velocity from 0.4 to 1.9 m/s for R-113 and 4.8 to 31.3 m/s for steam. For both fluids, the improvement of the c...

  17. Application of cross finned tubes in latent heat storages

    Energy Technology Data Exchange (ETDEWEB)

    Schwind, H.; Wolff, D. (Dortmund Univ. (Germany, F.R.). Lehrstuhl fuer Anlagentechnik); Brose, J. (Dortmund Univ. (Germany, F.R.). Arbeitsgruppe Chemieapparatebau)

    1978-01-01

    Heat storages, utilizing the latent heat of materials have in comparison with sensible heat storages the two fundamental advantages of small storage volumes and constant temperatures during charge and discharge. Known storage systems in the field of industrial heating may be replaced advantageous by latent heat storage systems. A new latent heat storage, applying storage material around vertical arranged cross finned tubes is presented. It results in good heat transfer rates and avoids degredation and stratification of salthydrates during operation. The scaling-up of a single cross finned tube to a compact unit with plate fins seems to be practicable without problems. Some experimental results are presented.

  18. FinTech – What's in a Name?

    OpenAIRE

    Zavolokina, Liudmila; Dolata, Mateusz; Schwabe, Gerhard

    2016-01-01

    FinTech, the word which originates from marriage of “finance” and “technology”, designates currently a novel, innovative and emerging field which attracts attention from the publicity. At the moment there is no universal understanding and definition of FinTech in the research, however, the topic is widely addressed by the English- and German-speaking press. In this study we aim to make insights into how the press and other popular media understand and frame FinTech, discussing definitions tha...

  19. FinTech – What's in a Name?

    OpenAIRE

    Zavolokina, Liudmila; Dolata, Mateusz; Schwabe, Gerhard

    2016-01-01

    FinTech, the word which originates from marriage of “finance” and “technology”, designates currently a novel, innovative and emerging field which attracts attention from the publicity. At the moment there is no universal understanding and definition of FinTech in the research, however, the topic is widely addressed by the English- and German-speaking press. In this study we aim to make insights into how the press and other popular media understand and frame FinTech, discussing definitions tha...

  20. Fundamental Characteristics of a Pinned Photodiode CMOS Pixels

    NARCIS (Netherlands)

    Xu, Y.

    2015-01-01

    This thesis gives an insightful analysis of the pinned photodiode 4T CMOS pixel from three different aspects. Firstly, from the charge accumulated aspect, the PPD full well capacity and related parameters of influence are investigated such as the pinning voltage, and transfer gate potential barrier.

  1. IMp: The customizable LEGO(®) Pinned Insect Manipulator.

    Science.gov (United States)

    Dupont, Steen; Price, Benjamin; Blagoderov, Vladimir

    2015-01-01

    We present a pinned insect manipulator (IMp) constructed of LEGO® building bricks with two axes of movement and two axes of rotation. In addition we present three variants of the IMp to emphasise the modular design, which facilitates resizing to meet the full range of pinned insect specimens, is fully customizable, collapsible, affordable and does not require specialist tools or knowledge to assemble.

  2. Computational analysis of heat transfer and pressure drop performance for internally finned tubes with three different longitudinal wavy fins

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qiu-Wang; Lin, Mei; Zeng, Min; Tian, Lin [Xi' an Jiaotong University, State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an, Shaanxi (China)

    2008-12-15

    Turbulent pressure drop and heat transfer characteristics in tubes with three different kinds of internally longitudinal fin patterns (interrupted wavy, sinusoidal wavy and plain) are numerically investigated for Re=904-4,520. The channel velocity, temperature, and turbulence fields are obtained to discern the mechanisms of heat transfer enhancement. Numerical results indicate that the steady and spatially periodic growth and disruption of cross-sectional vortices occur near the tube/fin walls along the streamwise locations. The thermal boundary layers near the tube/fin surfaces are thereby periodically interrupted, with heat transfer near the recirculation zones being enhanced. The overall heat transfer coefficients in wavy channels are higher than those in a plain fin channel, while with larger pressure drop penalties. At the same waviness, the interrupted wavy fin tube could enhance heat transfer by 72-90%, with more than 2-4 times of pressure drop penalty. Among the fins studied, the sinusoidal wavy fin has the best comprehensive performance. (orig.)

  3. Effect of Fin Geometry on Condensation Heat Transfer of Refrigerant R134a on Enhanced Finned Tubes

    Science.gov (United States)

    Takahashi, Hiroyuki; Saeki, Chikara; Koyama, Shigeru

    This paper presents the experimental results on the outside condensation heat tral1sfer coefficient of horizontal enhanced filmed tubes. Three different fin geometry types of three-dimensional enhanced finned tubes were tested. A low-fin-tube (LFT) 19 fin-per-inch (fpi) was also tested for reference. Experimental refrigerant used was R134a. The heat tral1sfer coefficient test was carried out at a condensing temperature of 40°C, at a cooling water velocity of 1.5 m/s, and the heat flux of 10 to 110 kW/m2K. The outside condensation heat transfer coefficient of all three dimensional enhanced finned tubes were approximately 1.9 times higher than that of LFTl9fpi at high heat flux range. In low heat flux range, the enhanced finned tube of small circumferential segmentation pitches at the fin tip was shown the highest outside heat transfer coefficient for all tubes tested.

  4. Cracking Bank PINs by Playing Mastermind

    Science.gov (United States)

    Focardi, Riccardo; Luccio, Flaminia L.

    The bank director was pretty upset noticing Joe, the system administrator, spending his spare time playing Mastermind, an old useless game of the 70ies. He had fought the instinct of telling him how to better spend his life, just limiting to look at him in disgust long enough to be certain to be noticed. No wonder when the next day the director fell on his chair astonished while reading, on the newspaper, about a huge digital fraud on the ATMs of his bank, with millions of Euros stolen by a team of hackers all around the world. The article mentioned how the hackers had 'played with the bank computers just like playing Mastermind', being able to disclose thousands of user PINs during the one-hour lunch break. That precise moment, a second before falling senseless, he understood the subtle smile on Joe's face the day before, while training at his preferred game, Mastermind.

  5. Flux pinning characteristics and irreversibility line in high temperature superconductors

    Science.gov (United States)

    Matsushita, T.; Ihara, N.; Kiuchi, M.

    1995-01-01

    The flux pinning properties in high temperature superconductors are strongly influenced by thermally activated flux motion. The scaling relation of the pinning force density and the irreversibility line in various high temperature superconductors are numerically analyzed in terms of the flux creep model. The effect of two factors, i.e., the flux pinning strength and the dimensionality of the material, on these properties are investigated. It is speculated that the irreversibility line in Bi-2212 superconductors is one order of magnitude smaller than that in Y-123, even if the flux pinning strength in Bi-2212 is improved up to the level of Y-123. It is concluded that these two factors are equally important in determination of the flux pinning characteristics at high temperatures.

  6. Nano-engineered pinning centres in YBCO superconducting films

    Science.gov (United States)

    Crisan, A.; Dang, V. S.; Mikheenko, P.

    2017-02-01

    For practical applications of superconducting materials in applied magnetic fields, artificial pinning centres in addition to natural ones are required to oppose the Lorentz force. These pinning centres are actually various types of defects in the superconductor matrix. The pinning centres can be categorised on their dimension (volume, surface or point) and on their character (normal cores or Δκ cores). Different samples have been produced by Pulsed Laser Deposition, with various thicknesses, temperatures and nanostructured additions to the superconducting matrix. They have been characterized by SQUID Magnetic Properties Measurement System and Physical Properties Measurement System, as well as by Transmission Electron Microscopy (TEM). Correlations between pinning architecture, TEM images, and critical currents at various fields and field orientations will be shown for a large number of YBa2Cu3Ox films with various types and architectures of artificial pinning centres.

  7. New Pin Puller Based on SMA Technology for Space Applications

    Science.gov (United States)

    Nava, Nestor; Collado, Marcelo; Cabás, Ramiro

    2014-07-01

    Two different versions of the Pin Puller were designed during this activity, such as one with 100 N and other with 500 N of pull force. The design of both versions is based on spheres which support the pin at the initial position and a compression spring driving once the release takes place by means of the SMA. The mechanical design of the Pin Pullers has been conceived in order to optimize the device's weight, reduce the parts complexity, and achieve a suitable stiffness. A qualification test campaign for the Pin Puller with 500 N of pull force has been developed in order to check the success of the proposed mechanism for space applications. The main performed tests have been thermal-vacuum actuation, thermal-vacuum cycling, sine vibration, and random vibration. The Pin Puller has presented successful results of actuation during the test campaign

  8. In vitro analysis of self-shearing retentive pins.

    Science.gov (United States)

    Collard, E W; Caputo, A A; Standlee, J P; Duncanson, M G

    1981-02-01

    Combining stress, analysis, microscopic examination, mechanical testing of the shear mechanism, and retention of the Reten Pin leads to the following conclusions: 1. The suggested 0.006 inch pin-channel mismatch induces high lateral and apical stresses. Microscopically, this was seen to correlate with injury to the dentin. 2. The degree of retention was increased by using a smaller pin-channel mismatch. This correlates with smaller stresses and reduced dentinal damage. 3. The shear mechanism acts in a uniform manner, with a relatively small variation from the mean. It is suggested that for the best results the manufacturer should supply larger twist drills and pins with a somewhat deeper self-shearing groove to minimize apical involvement during shearing of the handle from the pin.

  9. Pinning Lur’e Complex Networks via Output Feedback Control

    Directory of Open Access Journals (Sweden)

    Fang Liu

    2014-01-01

    Full Text Available Without requiring the full-state information of network nodes, this paper studies the pinning synchronization in a network of Lur’e dynamical systems based on the output feedback control strategy. Some simple pinning conditions are established for both undirected and directed Lur’e networks by using M-matrix theory and S-procedure technique. With the derived stability criteria, the pinning synchronization problem of large-scale Lur’e networks can be transformed to the test of a low-dimensional linear matrix inequality. Some remarks are further given to address the selection of pinned nodes and the design of pinning feedback gains. Numerical results are provided to demonstrate the effectiveness of the theoretical analysis.

  10. Retractable Pin Tools for the Friction Stir Welding Process

    Science.gov (United States)

    1998-01-01

    Two companies have successfully commercialized a specialized welding tool developed at the Marshall Space Flight Center (MSFC). Friction stir welding uses the high rotational speed of a tool and the resulting frictional heat created from contact to crush, 'stir' together, and forge a bond between two metal alloys. It has had a major drawback, reliance on a single-piece pin tool. The pin is slowly plunged into the joint between two materials to be welded and rotated as high speed. At the end of the weld, the single-piece pin tool is retracted and leaves a 'keyhole,' something which is unacceptable when welding cylindrical objects such as drums, pipes and storage tanks. Another drawback is the requirement for different-length pin tools when welding materials of varying thickness. An engineer at the MSFC helped design an automatic retractable pin tool that uses a computer-controlled motor to automatically retract the pin into the shoulder of the tool at the end of the weld, preventing keyholes. This design allows the pin angle and length to be adjusted for changes in material thickness and results in a smooth hole closure at the end of the weld. Benefits of friction stir welding, using the MSFC retractable pin tool technology, include the following: The ability to weld a wide range of alloys, including previously unweldable and composite materials; provision of twice the fatigue resistance of fusion welds and no keyholes; minimization of material distortion; no creation of hazards such as welding fumes, radiation, high voltage, liquid metals, or arcing; automatic retraction of the pin at the end of the weld; and maintaining full penetration of the pin.

  11. Some Exact Solutions of Nonlinear Fin Problem for Steady Heat Transfer in Longitudinal Fin with Different Profiles

    Directory of Open Access Journals (Sweden)

    M. D. Mhlongo

    2014-01-01

    Full Text Available One-dimensional steady-state heat transfer in fins of different profiles is studied. The problem considered satisfies the Dirichlet boundary conditions at one end and the Neumann boundary conditions at the other. The thermal conductivity and heat coefficients are assumed to be temperature dependent, which makes the resulting differential equation highly nonlinear. Classical Lie point symmetry methods are employed, and some reductions are performed. Some invariant solutions are constructed. The effects of thermogeometric fin parameter, the exponent on temperature, and the fin efficiency are studied.

  12. Determination of fin pitches for maximum performance index of L-footed spiral fin-and-tube heat exchangers

    OpenAIRE

    2015-01-01

    In this study, the fin pitches of L-footed spiral finned tube heat exchangers were determined for maximimum performance index. The experiments were done at various fin pitches (fp = 2.4, 3.2, and 4.2 mm) under the range of high Reynolds numbers (5,000–15,000). The test sections had a parallel and counter cross-flow arrangement having the number of tube row of 2. The two working fluids were the ambient air and hot water. The performance indexes (ζ1, ζ2, and ζ3) were used to analyze the experim...

  13. Steady-state and transient heat transfer through fins of complex geometry

    Directory of Open Access Journals (Sweden)

    Taler Dawid

    2014-06-01

    Full Text Available Various methods for steady-state and transient analysis of temperature distribution and efficiency of continuous-plate fins are presented. For a constant heat transfer coefficient over the fin surface, the plate fin can be divided into imaginary rectangular or hexangular fins. At first approximate methods for determining the steady-state fin efficiency like the method of equivalent circular fin and the sector method are discussed. When the fin geometry is complex, thus transient temperature distribution and fin efficiency can be determined using numerical methods. A numerical method for transient analysis of fins with complex geometry is developed. Transient temperature distributions in continuous fins attached to oval tubes is computed using the finite volume - finite element methods. The developed method can be used in the transient analysis of compact heat exchangers to calculate correctly the heat flow rate transferred from the finned tubes to the fluid.

  14. El proteccionismo de fin de siglo

    Directory of Open Access Journals (Sweden)

    Marcela SABATÉ SORT

    2010-02-01

    Full Text Available RESUMEN: Dentro del análisis de la política comercial de la Europa continental, este trabajo profundiza en la reacción proteccionista que, contrastando con la apertura anterior, caracteriza el final del siglo XIX y los primeros años del XX, justo hasta el comienzo de la Gran Guerra. Para ello indaga en los factores, especialmente las consecuencias de la "Gran Depresión", que provocan este cambio, en las políticas comerciales de los principales países europeos ante la crisis y en los niveles de protección establecidos. Unas reflexiones finales sobre el común movimiento de elevación arancelaria que preside la evolución de las políticas comerciales del continente en esta etapa y el diverso grado de protección decidido, permiten definir con exactitud la reacción proteccionista realmente acometida. Palabras Clave. Política comercial, Proteccionismo, Crisis económica, Estado, Fin de siglo. ABSTRACT: Within the analysis of the commercial policy of continental Europe, this study delves deeper into the protectionist reaction which, in contrast with the former openness, characterised the end of the nineteenth century and the beginning of the twentieth, right up until he beginning of the Great War. It inquires into the factors that provoked this change, especially the consequences of the Great Depression, and into the commercial policies of the main European countries in the face of this crisis, as well as the levels of protection established. Some final reflections on the common movement to raise tariffs which presided the evolution of the continent's commercial policies during this stage and the diverse degree of protection decided on make it possible to precisely define the protectionist action really undertaken. Key Words: Commercial Policy, Protectionism, Economic Crisis, State, Turn of the Century.

  15. Hydrodynamic properties of fin whale flippers predict maximum rolling performance.

    Science.gov (United States)

    Segre, Paolo S; Cade, David E; Fish, Frank E; Potvin, Jean; Allen, Ann N; Calambokidis, John; Friedlaender, Ari S; Goldbogen, Jeremy A

    2016-11-01

    Maneuverability is one of the most important and least understood aspects of animal locomotion. The hydrofoil-like flippers of cetaceans are thought to function as control surfaces that effect maneuvers, but quantitative tests of this hypothesis have been lacking. Here, we constructed a simple hydrodynamic model to predict the longitudinal-axis roll performance of fin whales, and we tested its predictions against kinematic data recorded by on-board movement sensors from 27 free-swimming fin whales. We found that for a given swimming speed and roll excursion, the roll velocity of fin whales calculated from our field data agrees well with that predicted by our hydrodynamic model. Although fluke and body torsion may further influence performance, our results indicate that lift generated by the flippers is sufficient to drive most of the longitudinal-axis rolls used by fin whales for feeding and maneuvering.

  16. The X-38 V-201 Fin Fold Actuation Mechanism

    Science.gov (United States)

    Lupo, Christian; Robertson, Brandan; Gafka, George

    2004-01-01

    The X-38 Vehicle 201 (V-201) is a space flight prototype lifting body vehicle that was designed to launch to orbit in the Space Shuttle orbiter payload bay. Although the project was cancelled in May 2003, many of the systems were nearly complete. This paper will describe the fin folding actuation mechanism flight subsystems and development units as well as lessons learned in the design, assembly, development testing, and qualification testing. The two vertical tail fins must be stowed (folded inboard) to allow the orbiter payload bay doors to close. The fin folding actuation mechanism is a remotely or extravehicular activity (EVA) actuated single fault tolerant system consisting of seven subsystems capable of repeatedly deploying or stowing the fins.

  17. Computation of boiling water on circular finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Fan, C.C.; Liaw, S.P. [National Taiwan Ocean Univ., Keelung (Taiwan, Province of China). Dept. of Mechanical and Marine Engineering

    1999-04-01

    This study investigates the maximum heat transfer rate and the critical temperature of circular finned tubes in a boiling liquid. The analysis is conducted numerically by solving a two-dimensional heat conduction equation in a steady state. The dependence between heat flux and the temperature at the inner wall of the tube is quantified. Varying the width, height, and pitch of fins, an optimal finned tube with efficient heat transfer rate can be obtained. In the theoretical approach the successive over relaxation (S.O.R.) accompanied with Multi-grid scheme is used. The local heat transfer rates are assumed to follow power-law-type temperature dependence. The initial guess at very high temperatures or so-called a cooling process is also executed in a same way. The results reveal that increasing either the width or the height of a fin increases the total heat transfer rate.

  18. Calculation base of flooded type evaporators with finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Brod, W.; Slipcevic, B.

    1989-03-01

    For the construction of flooded type evaporators with halogen refrigerants, the refrigeration industry is using finned tubes. Equations for thermodynamical calculations of the apparaturs are given, and explained with the aid of a calculation example.

  19. Review of Fin FET Technology and Circuit Design Challenges

    Directory of Open Access Journals (Sweden)

    Bibin Lawrence R,

    2015-12-01

    Full Text Available Considering the difficulties in planar CMOS transistor scaling to secure an acceptable gate to channel control FinFET based multi-gate (MuGFET devices have been proposed as a technology option for replacing the existing technology. The desirability of FinFET that it’s operation principle is same as CMOS process. This permits to lengthening the gate scaling beyond the planar transistor limits, sustaining a steep subthreshold slope, better performance with bias voltage scaling and good matching due to low doping concentration in the channel. There are, still, several challenges and limitations that FinFET technology has to face to be competitive with other technology options: Fin shape, pitch, isolation, doping, crystallographic orientation and stressing as well as device parasitic, performance and patterning approaches will be discussed.

  20. Flexible nanoscale high-performance FinFETs

    KAUST Repository

    Sevilla, Galo T.

    2014-10-28

    With the emergence of the Internet of Things (IoT), flexible high-performance nanoscale electronics are more desired. At the moment, FinFET is the most advanced transistor architecture used in the state-of-the-art microprocessors. Therefore, we show a soft-etch based substrate thinning process to transform silicon-on-insulator (SOI) based nanoscale FinFET into flexible FinFET and then conduct comprehensive electrical characterization under various bending conditions to understand its electrical performance. Our study shows that back-etch based substrate thinning process is gentler than traditional abrasive back-grinding process; it can attain ultraflexibility and the electrical characteristics of the flexible nanoscale FinFET show no performance degradation compared to its rigid bulk counterpart indicating its readiness to be used for flexible high-performance electronics.

  1. Experimental Investigation of Heat Transfer and Pressure Drop Characteristics of H-type Finned Tube Banks

    Directory of Open Access Journals (Sweden)

    Heng Chen

    2014-11-01

    Full Text Available H-type finned tube heat exchanger elements maintain a high capacity for heat transfer, possess superior self-cleaning properties and retain the ability to effect flue gas waste heat recovery in boiler renovations. In this paper, the heat transfer and pressure drop characteristics of H-type finned tube banks are studied via an experimental open high-temperature wind tunnel system. The effects of fin width, fin height, fin pitch and air velocity on fin efficiency, convective heat transfer coefficient, integrated heat transfer capacity and pressure drop are examined. The results indicate that as air velocity, fin height and fin width increase, fin efficiency decreases. Convective heat transfer coefficient is proportional to fin pitch, but inversely proportional to fin height and fin width. Integrated heat transfer capacity is related to fin efficiency, convective heat transfer coefficient and finned ratio. Pressure drop increases with the increase of fin height and fin width. Finally, predictive correlations of fin efficiency, Nusselt number and Euler Number are developed based on the experimental data.

  2. A pinning puzzle: two similar, non-superconducting chemical deposits in YBCO-one pins, the other does not

    Energy Technology Data Exchange (ETDEWEB)

    Sawh, Ravi-Persad; Weinstein, Roy; Gandini, Alberto; Skorpenske, Harley; Parks, Drew, E-mail: Weinstein@uh.ed [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Department of Physics, University of Houston, Houston, TX 77204-5005 (United States); Texas Center for Superconductivity at UH, University of Houston, Houston, TX 77204-5002 (United States)

    2009-09-15

    The pinning effects of two kinds of U-rich deposits in YBCO (YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}) are compared. One is a five-element compound, (U{sub 0.6}Pt{sub 0.4})YBa{sub 2}O{sub 6}, which is a paramagnetic double perovskite which forms as profuse stable nanosize deposits, and pins very well. The other is a four-element compound, (U{sub 0.4}Y{sub 0.6})BaO{sub 3}, which is a ferromagnetic single perovskite which forms as profuse stable nanosize deposits and pins very weakly or not at all. The pinning comparison is done with nearly equal deposit sizes and number of deposits per unit volume for the two compounds. Evidence for the pinning capability, chemical makeup, x-ray diffraction signature, and magnetic properties of the two compounds is reported.

  3. Validation of a Model for Ice Formation around Finned Tubes

    OpenAIRE

    Kamal A. R. Ismai; Fatima A. M. Lino

    2016-01-01

    Phase change materials although attaractive option for thermal storage applications its main drawback is the slow thermal response during charging and discharging processes due to their low thermal conductivity. The present study validates a model developed by the authors some years ago on radial fins as a method to meliorate the thermal performance of PCM in horizontal storage system. The developed model for the radial finned tube is based on pure conduction, the enthalpy approach and was di...

  4. Wind Fins: Novel Lower-Cost Wind Power System

    Energy Technology Data Exchange (ETDEWEB)

    David C. Morris; Dr. Will D. Swearingen

    2007-10-08

    This project evaluated the technical feasibility of converting energy from the wind with a novel “wind fin” approach. This patent-pending technology has three major components: (1) a mast, (2) a vertical, hinged wind structure or fin, and (3) a power takeoff system. The wing structure responds to the wind with an oscillating motion, generating power. The overall project goal was to determine the basic technical feasibility of the wind fin technology. Specific objectives were the following: (1) to determine the wind energy-conversion performance of the wind fin and the degree to which its performance could be enhanced through basic design improvements; (2) to determine how best to design the wind fin system to survive extreme winds; (3) to determine the cost-effectiveness of the best wind fin designs compared to state-of-the-art wind turbines; and (4) to develop conclusions about the overall technical feasibility of the wind fin system. Project work involved extensive computer modeling, wind-tunnel testing with small models, and testing of bench-scale models in a wind tunnel and outdoors in the wind. This project determined that the wind fin approach is technically feasible and likely to be commercially viable. Project results suggest that this new technology has the potential to harvest wind energy at approximately half the system cost of wind turbines in the 10kW range. Overall, the project demonstrated that the wind fin technology has the potential to increase the economic viability of small wind-power generation. In addition, it has the potential to eliminate lethality to birds and bats, overcome public objections to the aesthetics of wind-power machines, and significantly expand wind-power’s contribution to the national energy supply.

  5. Plates of the dinosaur stegosaurus: forced convection heat loss fins?

    Science.gov (United States)

    Farlow, J O; Thompson, C V; Rosner, D E

    1976-06-11

    It is suggested that the plates along the arched back and tail of Stegosaurus served an important thermoregulatory function as forced convection "fins." Wind tunnel experiments on finned models, internal heat conduction calculations, and direct observations of the morphology and internal structure of stegosaur plates support this hypothesis, demonstrating the comparative effectiveness of the plates as heat dissipaters, controllable through input blood flow rate, temperature, and body orientation (with respect to wind).

  6. Aerodynamic assessment of humpback whale ventral fin shapes

    OpenAIRE

    2011-01-01

    The ventral fins of the humpback whale (Megaptera novaeangliae) include a bulbous leading edge acting as a natural high-lift device. It has been suggested that application of this concept to wing design may yield advantages over traditional shapes (Miklosovic, et al., 2004). During the course of this project, the aerodynamic performance of whale fin models will be compared with conventional wing shapes. Based on the results of the study new wing design paradigms will be developed to improve t...

  7. Numerical Prediction of Pitch Damping Stability Derivatives for Finned Projectiles

    Science.gov (United States)

    2013-11-01

    spinner rocket, but not to a finned projectile. This study presents the first combined application of these methods for finned projectiles in which...and the U.S. Air Force Research Laboratory (AFRL) Aeroballistic Research Facility (ARF) (29) at Eglin Air Force Base in Florida. 2. Theoretical...numerical convergence, the results of which are presented in section4.2.2. 2.2 Steady Lunar Coning Method Murphy (24), Schiff (15, 16), Tobak and Schiff

  8. Blue and fin whale acoustics and ecology off Antarctic Peninsula

    OpenAIRE

    2006-01-01

    Blue (Balaenoptera musculus) and fin whales (B. physalus) in the Southern Ocean were subjects of extensive whaling industry during the twentieth century. Their current population numbers remain low, making population monitoring using traditional visual surveys difficult. Both blue and fin whales produce low frequency, regularly repeated calls and are suitable for acoustic monitoring. Eight, continuously recording acoustic recorders were deployed off the Western Antarctic Peninsula (WAP) betwe...

  9. CRACK PROBLEM UNDER SHEAR LOADING IN CUBIC QUASICRYSTAL

    Institute of Scientific and Technical Information of China (English)

    周旺民; 范天佑; 尹姝媛

    2003-01-01

    The axisymmetric elasticity problem of cubic quasicrystal is reduced to a single higher-order partial differential equation by introducing a displacement function. Based on the work, the analytic solutions of elastic field of cubic quasicrystal with a penny-shaped crack under the shear loading are found, and the stress intensity factor and strain energy release rate are determined.

  10. Cubic Polynomials with Real or Complex Coefficients: The Full Picture

    Science.gov (United States)

    Bardell, Nicholas S.

    2016-01-01

    The cubic polynomial with real coefficients has a rich and interesting history primarily associated with the endeavours of great mathematicians like del Ferro, Tartaglia, Cardano or Vieta who sought a solution for the roots (Katz, 1998; see Chapter 12.3: The Solution of the Cubic Equation). Suffice it to say that since the times of renaissance…

  11. An application of Cubical Cohomology to Adinkras and Supersymmetry Representations

    CERN Document Server

    Doran, Charles; Landweber, Greg

    2012-01-01

    An Adinkra is a class of graphs with certain signs marking its vertices and edges, which encodes off-shell representations of the super Poincar\\'e algebra. The markings on the vertices and edges of an Adinkra are cochains for cubical cohomology. This article explores the cubical cohomology of Adinkras, treating these markings analogously to characteristic classes on smooth manifolds.

  12. Fin characteristics of aerator devices with lateral deflectors

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; LI Dan; MA Fei; QIAN Shang-tuo

    2013-01-01

    The fins will be formed if the lateral deflectors in the side-walls with a bottom aerator device are improperly designed,and the flow regime downstream of the aerator device will be worsened.In this paper,the height and the length of the fins induced by the lateral deflectors are theoretically analyzed along with their influencing factors,and the fin characteristics are experimentally investigated on the basis of the theoretical analysis.It is shown that the intensities of the fins are strongly dependent on the ratio of the lateral cavity length to the bottom cavity length,and other factors,like the working head,the height and the angle of the lateral deflector,the flow Froude number around the aerator device,affect the fins indirectly through the changes of the lateral cavity length.When an aerator device with lateral deflectors is designed,it is crucial to match the above mentioned ratio,and to make the ratio of the two cavity lengths less than 1.0 in order to avoid the generation of the fins.

  13. Experiments with micro-fin tube in single phase

    Energy Technology Data Exchange (ETDEWEB)

    Copetti, J.B.; Macagnan, M.H.; De Souza, D.; Oliveski, R.D.C. [Universidade do Vale do Rio dos Sinos, Sao Leopoldo (Brazil). Department of Mechanical Engineering

    2004-12-01

    This work shows heat transfer and friction characteristics for water single-phase flow in micro-fin tubes. The analysis of thermal and hydraulic behavior from a laminar to a turbulent flow was carried out in an experimental setup with a 9.52 mm diameter micro-fin tube. The tube was wrapped up with an electrical resistance tape to supply a constant heat flux to its surface. Different operational conditions were considered in the heating tests. The inlet and outlet temperatures, differential wall temperatures along the tube, pressure drop and flow rate were measured. The relationships of heat flux and flow rate with heat transfer coefficient and pressure drop were analyzed. Under the same conditions, comparative experiments with an internally smooth tube were conducted. The micro-fin tube provides higher heat transfer performance than the smooth tube (in turbulent flow h{sub micro-fin}/h{sub smooth}=2.9). In spite of the increase in pressure drop ({delta}p{sub micro-fin}/{delta}p{sub smooth}=1.7) the heat transfer results were significantly higher (about 80%). This shows the advantages of this enhanced configuration in thermal performance related to conventional tubes. The smooth tube results were validated by the comparison with the Dittus-Boelter and Gnielinski correlations. For the micro-fin tube an empirical correlation to the heat transfer coefficient adjusted from the set of measured data is proposed. The values obtained are in conformity with experimental results. (author)

  14. Magneto-mechanical actuation model for fin-based locomotion

    CERN Document Server

    Carbajal, Juan Pablo; 10.2495/DN100331

    2011-01-01

    In this paper, we report the results from the analysis of a numerical model used for the design of a magnetic linear actuator with applications to fin-based locomotion. Most of the current robotic fish generate bending motion using rotary motors which implies at least one mechanical conversion of the motion. We seek a solution that directly bends the fin and, at the same time, is able to exploit the magneto-mechanical properties of the fin material. This strong fin-actuator coupling blends the actuator and the body of the robot, allowing cross optimization of the system's elements. We study a simplified model of an elastic element, a spring-mass system representing a flexible fin, subjected to nonlinear forcing, emulating magnetic interaction. The dynamics of the system is studied under unforced and periodic forcing conditions. The analysis is focused on the limit cycles present in the system, which allows the periodic bending of the fin and the generation of thrust. The frequency, maximum amplitude and cente...

  15. Transport in Porous Fins From Laminar to Turbulent Regime

    Science.gov (United States)

    Coletti, Filippo; Muramatsu, Kenshiro; Furciniti, Brian; Elkins, Chris; Eaton, John

    2012-11-01

    Lotus type porous metal has elongated pores of random size and spatial distribution but a common orientation. Sets of so-called lotus fins are obtained by slicing the metal into thin layers and stacking them in the flow path, forcing the fluid to pass through the pores. Lotus fins represent a promising alternative to metal foam heat exchangers, because they offer higher thermal conductivity and lower pressure drop. We have experimentally analyzed the fluid flow and heat transfer in lotus fins to determine their transport properties in a range of flow regimes. The investigated Reynolds numbers based on the pore diameter and inner velocity ranged from 100 to 4000. Three-dimensional mean velocity fields were obtained by magnetic resonance velocimetry performed on magnified replicas of the fins, allowing determination of the mechanical dispersion imposed by the random structure of the fins. Thermal measurements on non-conductive fins provided the global diffusivity coefficient, which accounts for molecular, mechanical and (at high Reynolds number) turbulent diffusion. The latter contribution was isolated and its relevance assessed as a function of the flow regime.

  16. Transcriptional Profiling of Caudal Fin Regeneration in Zebrafish

    Directory of Open Access Journals (Sweden)

    Michael Schebesta

    2006-01-01

    Full Text Available Regeneration of severed limbs in adult animals is restricted to urodele amphibians. Mammals, including humans, have very limited regenerative capabilities and even with proper treatment, only the tips of our digits can grow back. Teleost fish can regenerate amputated fins, the evolutionary ancestors of limbs. To elucidate the principles of limb-fin regeneration, we performed an Affymetrix microarray screen on regenerating caudal fins 12, 24, 48, and 72 h post amputation. Approximately 15,000 zebrafish transcripts were analyzed, identifying 829 transcripts as differentially expressed during regeneration. Of those, 563 were up-regulated and 266 were down-regulated. We constructed a comprehensive database containing expression data, functional assignment, and background information from the literature for each differentially expressed transcript. In order to validate our findings, we employed three approaches: (1 microarray expression analysis of genes previously implicated in fin regeneration, (2 RT-PCR analysis of genes newly identified as differentially expressed during regeneration, and (3 in situ hybridization of the up-regulated genes bambi, dlx5A, and her6. Moreover, we show that Smad 1/5/8 proteins, effector molecules of Bmp signaling, are phosphorylated during fin regeneration. Taken together, we provide a comprehensive database of fin regeneration that will serve as an important tool for understanding the molecular mechanisms of regeneration.

  17. Rational Cubics and Conics Representation: A Practical Approach

    Directory of Open Access Journals (Sweden)

    M. Sarfraz

    2012-08-01

    Full Text Available A rational cubic spline, with one family of shape parameters, has been discussed with the view to its application in Computer Graphics. It incorporates both conic sections and parametric cubic curves as special cases. The parameters (weights, in the description of the spline curve can be used to modify the shape of the curve, locally and globally, at the knot intervals. The rational cubic spline attains parametric   smoothness whereas the stitching of the conic segments preserves visually reasonable smoothness at the neighboring knots. The curve scheme is interpolatory and can plot parabolic, hyperbolic, elliptic, and circular splines independently as well as bits and pieces of a rational cubic spline.Key Words: Computer Graphics, Interpolation, Spline, Conic, Rational Cubic

  18. On cubic equations over $P-$adic field

    CERN Document Server

    Mukhamedov, Farrukh; Saburov, Mansoor

    2012-01-01

    We provide a solvability criteria for a depressed cubic equation in domains $\\bz_p^{*},\\bz_p,\\bq_p$. We show that, in principal, the Cardano method is not always applicable for such equations. Moreover, the numbers of solutions of the depressed cubic equation in domains $\\bz_p^{*},\\bz_p,\\bq_p$ are provided. Since $\\bbf_p\\subset\\bq_p,$ we generalize J.-P. Serre's \\cite{JPSJ} and Z.H.Sun's \\cite{ZHS1,ZHS3} results concerning with depressed cubic equations over the finite field $\\bbf_p$. Finally, all depressed cubic equations, for which the Cardano method could be applied, are described and the $p-$adic Cardano formula is provided for those cubic equations.

  19. The Body Center Cubic Quark Lattice Model

    CERN Document Server

    Lin Xu, Jiao

    2004-01-01

    The Standard Model while successful in many ways is incomplete; many questions remain. The origin of quark masses and hadronization of quarks are awaiting an answer. From the Dirac sea concept, we infer that two kinds of elementary quarks (u(0) and d(0)) constitute a body center cubic (BCC) quark lattice with a lattice constant a < $10^{-18}$m in the vacuum. Using energy band theory and the BCC quark lattice, we can deduce the rest masses and the intrinsic quantum numbers (I, S, C, b and Q) of quarks. With the quark spectrum, we deduce a baryon spectrum. The theoretical spectrum is in agreement well with the experimental results. Not only will this paper provide a physical basis for the Quark Model, but also it will open a door to study the more fundamental nature at distance scales <$10^{-18}$m. This paper predicts some new quarks $u_{c}$(6490) and d$_{b}$(9950), and new baryons $\\Lambda_{c}^{+}$(6500), $\\Lambda_{b}^{0}$(9960).

  20. Implications of fin profiles on overall performance and weight reduction of a fin and tube heat exchanger

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2017-01-01

    on a cross-flow type fin and tube heat exchanger design for a waste heat recovery application is conducted. The geometric profile of the fin is characterized by a dimensionless design variable named aspect ratio which is parametrically varied to obtain different profiles. Two cases, case-I, and case......Fin and tube heat exchangers are being used in several industrial applications by means of novel design and optimized performance. Improvements in geometric design may deliver energy efficient and cost-effective heat exchanger performance with reduced weight. In this paper, a systematic study...... design. Results show that the overall performance improves by approximately 6.76% and 17.33% with a reduction in net unit weight by approximately 27.58% and 6.82% on changing the aspect ratio from 1.0 to 0.1 in case-I and case-II, respectively. In addition, feasible fin profile for a waste heat recovery...

  1. Dissecting Pin1 and phospho-pRb regulation.

    Science.gov (United States)

    Rizzolio, Flavio; Caligiuri, Isabella; Lucchetti, Chiara; Fratamico, Robert; Tomei, Valentina; Gallo, Gaia; Agelan, Alexis; Ferrari, Giovanni; Toffoli, Giuseppe; Klein-Szanto, Andres J; Giordano, Antonio

    2013-01-01

    The activity of the Retinoblastoma protein, the master regulator of the cell cycle, is finely regulated by phosphorylation. CDKs and cyclins are major players in phosphorylation and it has been recently discovered that the prolyl isomerase Pin1 is an essential protein that orchestrates this process. In this article, we report new findings regarding the role of Pin1 in the pRb pathway. Our data suggest that PI3K, CDKs, and the Pin1 axis have a critical role in sustaining the complete phosphorylation of pRb. Furthermore, we analyze the correlation between Pin1 and pRb phosphorylation in vivo. We show that, in human malignant glioma tissue microarrays (TMA) and in Pin1 knockout (KO) mice, there is a positive correlation between Pin1 and pRb phosphorylation. Prospectively, our findings suggest that the synergism between CDKs, Pin1, and PI3K inhibitors hold great promise for targeted pharmacological treatment of cancer patients, with the possibility of reaching high effectiveness at tolerated doses.

  2. Some exact solutions of nonlinear fin problem for steady heat transfer in longitudinal fin with different profiles

    CSIR Research Space (South Africa)

    Mhlongo, MD

    2014-05-01

    Full Text Available Solutions of Nonlinear Fin Problem for Steady Heat Transfer in Longitudinal Fin with Different Profiles M. D. Mhlongo1 and R. J. Moitsheki2 1 Defence, Peace, Safety and Security, Landward Sciences, Council for Scientific and Industrial Research, P.O. Box 395... efficiency are studied. 1. Introduction Heat transfer through extended surfaces has been studied quite extensively [1], perhaps because of its frequent applica- tions in engineering. Through the process of mathematical modeling, heat transfer problems...

  3. Alar Pinning in Rigid External Distraction for Midfacial Hypoplasia.

    Science.gov (United States)

    Yu, Jenny L; Woo, Albert S

    2017-09-01

    Distraction osteogenesis with a rigid external distractor is a widely accepted treatment for midfacial hypoplasia. In this study, the authors introduce the utilization of alar pinning with the external halo distractor for maxillary advancement, in place of an oral splint. A retrospective chart review was conducted of 7 patients who successfully underwent distraction osteogenesis using the alar pinning technique. Midfacial hypoplasia was secondary to Crouzon syndrome (n = 4), Apert syndrome (n = 1), Pfeiffer syndrome (n = 1), or bacterial meningitis (n = 1). Three patients were managed with monobloc osteotomies, 2 with Le Fort III osteotomies, 1 with Le Fort III osteotomy and frontoorbital advancement, and 1 with Le Fort I osteotomy alone. Patient charts were analyzed for postoperative course and complications relating to the alar pins. Two patients had minor complications specifically related to the alar pins. One patient had concern for a mild skin infection at a pin site that resolved with oral antibiotics. The other patient had loosening of an alar pin, which did not require operative management. Retrospective chart review indicated that all patients were pleased with their results from the distraction, and no patients opted for further advancement. Utilization of alar pin sites for external distraction is a feasible and reasonable option for treatment of midfacial hypoplasia involving a Le Fort osteotomy or monobloc procedure. Fixation sites within the alar crease minimize the visibility of pin site scars and eliminate the need for a custom-made oral splint, which prevents usage of the upper dentition and frequently requires consulting a dentist or orthodontist for fabrication. Alar pinning with an external halo distraction system for management of midfacial hypoplasia has minimal complications and is an alternative to using a custom-made oral splint.

  4. The performance of a new gas to gas heat exchanger with strip fin

    NARCIS (Netherlands)

    Wang, J.; Hirs, G.G.; Rollmann, P.

    1999-01-01

    A compact gas to gas heat exchanger needs large heat transfer areas on both fluid sides. This can be realised by adding secondary surfaces. The secondary surfaces are plate fin, strip fin, and louvered fin, etc. The fins extend the heat transfer surfaces and promote turbulence. This paper presents

  5. Fish larvae exploit edge vortices along their dorsal and ventral fin folds to propel themselves

    NARCIS (Netherlands)

    Li, G.; Müller, U.K.; Leeuwen, van J.L.; Liu, Hao

    2016-01-01

    Larvae of bony fish swim in the intermediate Reynolds number (Re) regime,
    using body- and caudal-fin undulation to propel themselves. They share a
    median fin fold that transforms into separate median fins as they grow into
    juveniles. The fin fold was suggested to be an adaption for locom

  6. "Safety pin"--a question to its safety!

    Science.gov (United States)

    Thapa Chettri, S; Bhattarai, M; Karki, S; Regmi, S; Mathur, N N

    2010-03-01

    Foreign body ingestion is not an uncommon problem in children. They can ingest various foreign objects and one of such objects is a safety pin. The ingestion of such foreign body is not widely reported in the literature. This case highlights the risk of accidental ingestion of safety pin used on child's clothing to protect him from cold that can result in lethal complications. In a poor developing country like Nepal, this case serves to address all mothers alerting them of their ignorance while using safety pin in infants. In addition, physicians are reminded to obtain a detailed inquiry of suspected foreign body ingestion in every child with the history of dysphagia.

  7. Noises of p-i-n UV photodetectors

    Science.gov (United States)

    Gasparyan, Ferdinand V.; Korman, Can E.; Melkonyan, Slavik V.

    2007-06-01

    Investigations of the static characteristics, responsivity, internal noises, and detectivity of the forward biased p-i-n photodetectors made on wide bandgap compensated semiconductors operating in double injection regime are presented. Noise related calculations are performed by utilizing "Impedance Field Method". Numerical simulations are made assessing 4H-SiC and GaN biased p-i-n photodiodes noise related characteristics. It is shown that forward biased p-i-n photodiodes have low level of thermal and generation-recombination noises and high values of sensitivity and detectivity at the room temperature.

  8. A Division in PIN-Mediated Auxin Patterning during Organ Initiation in Grasses

    Science.gov (United States)

    O'Connor, Devin L.; Runions, Adam; Sluis, Aaron; Bragg, Jennifer; Vogel, John P.

    2014-01-01

    The hormone auxin plays a crucial role in plant morphogenesis. In the shoot apical meristem, the PIN-FORMED1 (PIN1) efflux carrier concentrates auxin into local maxima in the epidermis, which position incipient leaf or floral primordia. From these maxima, PIN1 transports auxin into internal tissues along emergent paths that pattern leaf and stem vasculature. In Arabidopsis thaliana, these functions are attributed to a single PIN1 protein. Using phylogenetic and gene synteny analysis we identified an angiosperm PIN clade sister to PIN1, here termed Sister-of-PIN1 (SoPIN1), which is present in all sampled angiosperms except for Brassicaceae, including Arabidopsis. Additionally, we identified a conserved duplication of PIN1 in the grasses: PIN1a and PIN1b. In Brachypodium distachyon, SoPIN1 is highly expressed in the epidermis and is consistently polarized toward regions of high expression of the DR5 auxin-signaling reporter, which suggests that SoPIN1 functions in the localization of new primordia. In contrast, PIN1a and PIN1b are highly expressed in internal tissues, suggesting a role in vascular patterning. PIN1b is expressed in broad regions spanning the space between new primordia and previously formed vasculature, suggesting a role in connecting new organs to auxin sinks in the older tissues. Within these regions, PIN1a forms narrow canals that likely pattern future veins. Using a computer model, we reproduced the observed spatio-temporal expression and localization patterns of these proteins by assuming that SoPIN1 is polarized up the auxin gradient, and PIN1a and PIN1b are polarized to different degrees with the auxin flux. Our results suggest that examination and modeling of PIN dynamics in plants outside of Brassicaceae will offer insights into auxin-driven patterning obscured by the loss of the SoPIN1 clade in Brassicaceae. PMID:24499933

  9. Cytoskeletal dynamics of the teleostean fin ray during fin epimorphic regeneration.

    Science.gov (United States)

    Santos-Ruiz, Leonor; Santamaría, Jesús Alberto; Becerra, José

    2005-04-01

    Teleost fishes can regenerate their fins by epimorphic regeneration, a process that involves the transition of the formerly quiescent tissues of the stump to an active, growing state. This involves dynamic modifications of cell phenotype and behavior that must rely on alterations of the cytoskeleton. We have studied the spatial and temporal distribution of three main components of the cytoskeleton (actin, keratin and vimentin) in the regenerating fin, in order to establish putative relationships between cell cytoskeleton and cell behavior. According to our results, the massive rearrangement undergone by the epidermis right after injury, which takes place by cell migration, correlates with a transient down-regulation of keratin and a strong up-regulation of actin in the epidermal cells. During the subsequent epidermal growth, based on cell proliferation, keratin normal pattern is recovered while actin is down-regulated, although not to normal (quiescent) levels. The epidermal basal layer in contact with the blastema displays a particular cytoskeletal profile, different to that of the rest of the epidermal cells, which reflects its special features. In the connective tissue compartment, somatic cells do not contain vimentin, but keratin, as intermediate filament. Proliferative and migrative activation of these cells after injury correlates with actin up-regulation. Although this initial activation does not involve keratin down-regulation, blastemal cells were later observed to lack keratin, suggesting that such cytoskeletal modification might be needed for connective tissue cells to dedifferentiate and form the blastema. Cell differentiation in the newly formed, regenerated ray is accompanied by actin down-regulation and keratin up-regulation.

  10. A PWR Thorium Pin Cell Burnup Benchmark

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Kevan Dean; Zhao, X.; Pilat, E. E; Hejzlar, P.

    2000-05-01

    As part of work to evaluate the potential benefits of using thorium in LWR fuel, a thorium fueled benchmark comparison was made in this study between state-of-the-art codes, MOCUP (MCNP4B + ORIGEN2), and CASMO-4 for burnup calculations. The MOCUP runs were done individually at MIT and INEEL, using the same model but with some differences in techniques and cross section libraries. Eigenvalue and isotope concentrations were compared on a PWR pin cell model up to high burnup. The eigenvalue comparison as a function of burnup is good: the maximum difference is within 2% and the average absolute difference less than 1%. The isotope concentration comparisons are better than a set of MOX fuel benchmarks and comparable to a set of uranium fuel benchmarks reported in the literature. The actinide and fission product data sources used in the MOCUP burnup calculations for a typical thorium fuel are documented. Reasons for code vs code differences are analyzed and discussed.

  11. Multi-pin chemiresistors for microchemical sensors

    Science.gov (United States)

    Ho, Clifford K.

    2007-02-20

    A multi-pin chemiresistor for use in microchemical sensors. A pair of free-standing, bare wires is supported by an electrically insulating support, and are oriented parallel to each other and spaced closely together. A free-standing film of a chemically sensitive polymer that swells when exposed to vapors of a volatile chemical is formed in-between the pair of closely-spaced wires by capillary action. Similar in construction to a thermocouple, this "chemicouple" is relatively inexpensive and easy to fabricate by dipping the pair of bare wires into a bath of well-mixed chemiresistor ink. Also, a chemiresistor "stick" is formed by dipping an electrically insulating rod with two or more linear or spiral-wrapped electrical traces into the bath of well-mixed chemiresistor ink, which deposits a uniform coating of the chemically sensitive polymer on the rod and the electrical traces. These "sticks" can be easily removed and replaced from a multi-chemiresistor plug.

  12. Thermal experiment of silicon PIN detector

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong-Fei; ZOU Ji-Qing; SHI Wei-Hong; ZOU Hong; HU Ran-Sheng; TIAN Da-Yu

    2008-01-01

    The experiment of this paper is the thermal test of the leakage current of silicon PIN detector.Raising temperature may cause the detector to increase leakage current,decrease depletion and increase noise.Three samples are used in the experiment.One (called △E) is the sample of 100 tan in thickness.The other two (called E1 and E2) are stacks of five detectors of 1000 μm in thickness.All of them are 12 mm in diameter.The experiment has been done for 21 hours and with power on continuously.The samples have undergone more than 60 ℃ for about one hour.They are not degenerated when back to the room temperature.The depletion rate is temperature and bias voltage related.With the circuit of the experiment and temperature at 35 ℃,△E is still depleted while E1 and E2 are 94.9% and 99.7% depleted respectively.The noises of the samples can be derived from the values at room temperature and the thermal dependence of the leakage currents.With the addition of the noise of the pre-amplifier,the noises of E1,E2 and AE at 24 ℃ are 16.4,16.3,and 10.5 keV (FWHM) respectively while at 35 ℃ are about 33.6,33.1,and 20.6 keV (FWHM) respectively.

  13. Superconducting vortex pinning with artificial magnetic nanostructures.

    Energy Technology Data Exchange (ETDEWEB)

    Velez, M.; Martin, J. I.; Villegas, J. E.; Hoffmann, A.; Gonzalez, E. M.; Vicent, J. L.; Schuller, I. K.; Univ. de Oviedo-CINN; Unite Mixte de Physique CNRS/Thales; Univ. Paris-Sud; Univ.Complutense de Madrid; Univ. California at San Diego

    2008-11-01

    This review is dedicated to summarizing the recent research on vortex dynamics and pinning effects in superconducting films with artificial magnetic structures. The fabrication of hybrid superconducting/magnetic systems is presented together with the wide variety of properties that arise from the interaction between the superconducting vortex lattice and the artificial magnetic nanostructures. Specifically, we review the role that the most important parameters in the vortex dynamics of films with regular array of dots play. In particular, we discuss the phenomena that appear when the symmetry of a regular dot array is distorted from regularity towards complete disorder including rectangular, asymmetric, and aperiodic arrays. The interesting phenomena that appear include vortex-lattice reconfigurations, anisotropic dynamics, channeling, and guided motion as well as ratchet effects. The different regimes are summarized in a phase diagram indicating the transitions that take place as the characteristic distances of the array are modified respect to the superconducting coherence length. Future directions are sketched out indicating the vast open area of research in this field.

  14. Ideal glass transitions by random pinning

    Science.gov (United States)

    Cammarota, Chiara; Biroli, Giulio

    2012-01-01

    We study the effect of freezing the positions of a fraction c of particles from an equilibrium configuration of a supercooled liquid at a temperature T. We show that within the random first-order transition theory pinning particles leads to an ideal glass transition for a critical fraction c = cK(T) even for moderate supercooling; e.g., close to the Mode-Coupling transition temperature. First we derive the phase diagram in the T - c plane by mean field approximations. Then, by applying a real-space renormalization group method, we obtain the critical properties for |c - cK(T)| → 0, in particular the divergence of length and time scales, which are dominated by two zero-temperature fixed points. We also show that for c = cK(T) the typical distance between frozen particles is related to the static point-to-set length scale of the unconstrained liquid. We discuss what are the main differences when particles are frozen in other geometries and not from an equilibrium configuration. Finally, we explain why the glass transition induced by freezing particles provides a new and very promising avenue of research to probe the glassy state and ascertain, or disprove, the validity of the theories of the glass transition. PMID:22623524

  15. Experimental Study on Condensation of Pure Refrigerants in Horizontal Micro-fin Tubes

    Science.gov (United States)

    Yonemoto, Ryuichiro; Koyama, Shigeru

    This paper presents the heat transfer and pressure drop correlations for condensation in micro-fin tubes. Experimental data for eleven micro-fin tubes with different fin dimensions were used, and the refrigerants tested were R22, R123 and R134a. The predicted results using new correlations show good agreement with experimental results within an absolute deviation of ±30%. Experimental results for the micro-fin tubes were also compared with previous correlations for micro-fin Tubes.

  16. Defective Fin Regeneration in Medaka Fish (Oryzias latipes) with Hypothyroidism full access

    OpenAIRE

    Sekimizu, Koshin; Tagawa, Masatomo; Takeda, Hiroyuki

    2007-01-01

    Wild-type medaka are known to have remarkable capabilities of fin, or epimorphic, regeneration. However, a hypothyroid mutant, kamaitachi (kmi), frequently suffers from injury in fins, suggesting an important role of thyroid hormone in fin regeneration. This led us to examine the relationship between thyroid hormone and fin regeneration using medaka as a model. For this, we first set up a medaka experimental system in which the rate of regeneration was statistically analyzed after caudal fin ...

  17. Procedure of recovery of pin-by-pin fields of energy release in the core of VVER-type reactor for the BIPR-8 code

    Science.gov (United States)

    Gordienko, P. V.; Kotsarev, A. V.; Lizorkin, M. P.

    2014-12-01

    The procedure of recovery of pin-by-pin energy-release fields for the BIPR-8 code and the algorithm of the BIPR-8 code which is used in nodal computation of the reactor core and on which the recovery of pin-by-pin fields of energy release is based are briefly described. The description and results of the verification using the module of recovery of pin-by-pin energy-release fields and the TVS-M program are given.

  18. Pins, dowels, and other retentive devices in posterior teeth.

    Science.gov (United States)

    Jacobi, R; Shillingburg, H T

    1993-07-01

    Devices used to increase retention of restorations to severely damaged posterior teeth are described, with an emphasis on pins and dowels. Advantages and disadvantages of different techniques and measures to help prevent and correct problems are presented.

  19. Characterization of vortex pinning through the Campbell length

    Science.gov (United States)

    Willa, Roland; Geshkenbein, Vadim B.; Blatter, Gianni

    Vortex pinning is decisive in establishing dissipation-free current flow in a type-II superconductor; knowledge and optimization of the pinning landscape (pinscape) is of major importance for applications. The ac magnetic response, characterized by the Campbell penetration depth λC, provides valuable information on the pinscape, besides the critical current density jc. While microscopic derivations of jc are available both in the weak and strong pinning limits, this is not the case for the Campbell length, whose understanding has remained on a phenomenological level so far. Based on the microscopic theory of strong pinning, we have established a proper link between the Campbell length and the pinscape parameters. This new quantitative formalism captures all experimentally observed signatures, among which are the dependence of λC on the vortex state preparation and the hysteresis in λC upon thermal cycling the field-cooled state.

  20. PIN1 in breast development and cancer: a clinical perspective.

    Science.gov (United States)

    Rustighi, Alessandra; Zannini, Alessandro; Campaner, Elena; Ciani, Yari; Piazza, Silvano; Del Sal, Giannino

    2017-02-01

    Mammary gland development, various stages of mammary tumorigenesis and breast cancer progression have the peptidyl-prolyl cis/trans isomerase PIN1 at their centerpiece, in virtue of the ability of this unique enzyme to fine-tune the dynamic crosstalk between multiple molecular pathways. PIN1 exerts its action by inducing conformational and functional changes on key cellular proteins, following proline-directed phosphorylation. Through this post-phosphorylation signal transduction mechanism, PIN1 controls the extent and direction of the cellular response to a variety of inputs, in physiology and disease. This review discusses PIN1's roles in normal mammary development and cancerous progression, as well as the clinical impact of targeting this enzyme in breast cancer patients.

  1. 8 Pin RIC Socket for Hearing Aid Applications

    DEFF Research Database (Denmark)

    Islam, Aminul; Hansen, Hans Nørgaard; Davids, Søren;

    2012-01-01

    process and the other one is fully automated process. This paper presents the entire process chain for both the concepts and makes a comparative analysis based on the experimental investigation and validation. The work presented here can be a source of valuable information for industrial users......The current paper presents the development of an 8 Pin RIC (Receiver in the canal) Socket for hearing instruments within the framework of the COTECH project. There are 8 industrial demonstrators developed in COTECH based on the converged product and process design. Sonion’s 8 Pin RIC Socket is one...... of them. 8 Pin RIC Socket is a functionally versatile product which can combine many different functions and presents many advantages compared with the previous 3 Pin RIC Socket. For the demonstrator production of the new Socket, two different production concepts were chosen- one based on semi-automated...

  2. Pinning impulsive directed coupled delayed dynamical network and its applications

    Science.gov (United States)

    Lin, Chunnan; Wu, Quanjun; Xiang, Lan; Zhou, Jin

    2015-01-01

    The main objective of the present paper is to further investigate pinning synchronisation of a complex delayed dynamical network with directionally coupling by a single impulsive controller. By developing the analysis procedure of pinning impulsive stability for undirected coupled dynamical network previously, some simple yet general criteria of pinning impulsive synchronisation for such directed coupled network are derived analytically. It is shown that a single impulsive controller can always pin a given directed coupled network to a desired homogenous solution, including an equilibrium point, a periodic orbit, or a chaotic orbit. Subsequently, the theoretical results are illustrated by a directed small-world complex network which is a cellular neural network (CNN) and a directed scale-free complex network with the well-known Hodgkin-Huxley neuron oscillators. Numerical simulations are finally given to demonstrate the effectiveness of the proposed control methodology.

  3. Cubic B-spline curve approximation by curve unclamping

    OpenAIRE

    Chen, Xiao-Diao; Ma, Weiyin; Paul, Jean-Claude

    2010-01-01

    International audience; A new approach for cubic B-spline curve approximation is presented. The method produces an approximation cubic B-spline curve tangent to a given curve at a set of selected positions, called tangent points, in a piecewise manner starting from a seed segment. A heuristic method is provided to select the tangent points. The first segment of the approximation cubic B-spline curve can be obtained using an inner point interpolation method, least-squares method or geometric H...

  4. On q-power cycles in cubic graphs

    DEFF Research Database (Denmark)

    Bensmail, Julien

    2017-01-01

    In the context of a conjecture of Erdos and Gyárfás, we consider, for any q ≥ 2, the existence of q-power cycles (i.e. with length a power of q) in cubic graphs. We exhibit constructions showing that, for every q ≥ 3, there exist arbitrarily large cubic graphs with no q-power cycles. Concerning...... the remaining case q = 2 (which corresponds to the conjecture of Erdos and Gyárfás), we show that there exist arbitrarily large cubic graphs whose only 2-power cycles have length 4 only, or 8 only....

  5. On q-power cycles in cubic graphs

    DEFF Research Database (Denmark)

    Bensmail, Julien

    2016-01-01

    In the context of a conjecture of Erdos and Gyárfás, we consider, for any q ≥ 2, the existence of q-power cycles (i.e. with length a power of q) in cubic graphs. We exhibit constructions showing that, for every q ≥ 3, there exist arbitrarily large cubic graphs with no q-power cycles. Concerning...... the remaining case q = 2 (which corresponds to the conjecture of Erdos and Gyárfás), we show that there exist arbitrarily large cubic graphs whose only 2-power cycles have length 4 only, or 8 only....

  6. [Py-Desmanet pinning in distal radius fractures].

    Science.gov (United States)

    Alexa, O; Popia, I

    2009-01-01

    Internal fixation by pinning is one of the most used methods of surgical treatment in fractures of the distal extremity of the radius. As in stable fractures a styloid pinning is satisfactory, in unstable fractures however we must resort to different patterns of pin insertion, in order to effectively prevent the secondary displacement of the fractured fragments. The elastic pinning described by Py and Desmanet is one of the possibilities of inserting the pins. The principle of this method is to use the bending-induced tension in the pins to counteract the postero-lateral displacing forces. The authors have treated by this technique five patients with distal radius fractures (3 women and 2 men) about 56 years of average age, all with good-quality bone, all with Colles' fracture pattern (2-4 cm above the radio-carpal articulation, no articular involvement, posterior displacement of the distal fragment). The reduction of the fractures was achieved by closed manipulation and controlled intraoperatively with the C-arm. We preferred to reduce the fractures before inserting the pins, although this is not compulsory, according to the authors of the technique. The approach was minimally-invasive, through two 1-cm long incisions. The pins, previously blunted and curved along the last centimeters, were introduced using a "T"-shaped handle. The potential complications, consisting of injuries of the many elements which cross the region, were avoided by sufficiently long incisions and identification and retraction of these elements (tendons, nervous branches) in order not to penetrate them with the pins. The aftertreatment consisted of immediate mobilization of the wrist in one patient, 21-day splinting in other two and 30-day splinting in the last two, depending on the intraoperative assessment of the stability of the fixation. The pins were removed at 45 days postoperatively in all cases. There were no complications such as loss of reduction or pin migration. In all cases

  7. The compressibility of cubic white and orthorhombic, rhombohedral, and simple cubic black phosphorus

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Simon M; Zaug, Joseph

    2010-03-10

    The effect of pressure on the crystal structure of white phosphorus has been studied up to 22.4 GPa. The ?alpha phase was found to transform into the alpha' phase at 0.87 +- 0.04 GPa with a volume change of 0.1 +- 0.3 cc/mol. A fit of a second order Birch- Murnaghan equation to the data gave Vo = 16.94 ? 0.08 cc/mol and Ko = 6.7 +- 0.5 GPa for the alpha phase and Vo = 16.4 +- 0.1 cc/mol and Ko = 9.1 +- 0.3 GPa for the alpha' phase. The alpha' phase was found to transform to the A17 phase of black phosphorus at 2.68 +- 0.34 GPa and then with increasing pressure to the A7 and then simple cubic phase of black phosphorus. A fit of a second order Birch-Murnaghan equation to our data combined with previous measurements gave Vo = 11.43 +- 0.05 cc/mol and Ko = 34.7 +- 0.5 GPa for the A17 phase, Vo = 9.62 +- 0.01 cc/mol and Ko = 65.0 +- 0.6 GPa for the A7 phase and , Vo = 9.23 +- 0.01 cc/mol and Ko = 72.5 +- 0.3 GPa for the simple cubic phase.

  8. FinFET Architecture Analysis and Fabrication Mechanism

    Directory of Open Access Journals (Sweden)

    Sarman K Hadia

    2011-09-01

    Full Text Available In view of difficulties of the planar MOSFET technology to get the acceptable gate control over the channel FinFET technology based on multiple gate devices is better technology option for further shrinking the size of the planar MOSFET [1]. For double gate SOI- MOSFET the gates control the channel created between source and drain terminal effectively. So the several short channel effects like DIBL, subthreshold swing, gate leakage current etc. without increasing the carrier concentration into the channel. This paper mainly deals with detail description about the DG MOSFET structure and its particular type named as FinFET technology and its fabrication mechanism is also described. Below the 50nm technology FinFET has better controlling over the several short channel effects. In section one the introduction is given, section two describe the Evaluation from previous technology, section three describe the DG MOSFET structure and its type, section four describe the FinFET technology, section five describe the fabrication mechanism of the FinFET technology and finally conclusions given in section six.

  9. Fin Buffeting Features of an Early F-22 Model

    Science.gov (United States)

    Moses, Robert W.; Huttsell, Lawrence

    2000-01-01

    Fin buffeting is an aeroelastic phenomenon encountered by high performance aircraft, especially those with twin vertical tails that must operate at high angles of attack. This buffeting is a concern from fatigue and inspection points of view. To date, the buffet (unsteady pressures) and buffeting (structural response) characteristics of the F-15 and F/A-18 fins have been studied extensively using flow visualization, flow velocity measurements, pressure transducers, and response gages. By means of windtunnel and flight tests of the F-15 and F/A-18, this phenomenon is well studied to the point that buffet loads can be estimated and fatigue life can he increased by structural enhancements to these airframes. However, prior to the present research, data was not available outside the F-22 program regarding fin buffeting on the F-22 configuration. During a test in the Langley Transonic Dynamics Tunnel, flow visualization and unsteady fin surface pressures were recorded for a 13.3%-scale F-22 model at high angles of attack for the purpose of comparing with results available for similar aircraft configurations. Details of this test and fin buffeting are presented herein.

  10. Vortical structures in the wake of an undulating fin

    Science.gov (United States)

    Dewey, Peter A.; Carriou, Antoine; Smits, Alexander J.

    2010-11-01

    Batoid fish such as the manta ray propel themselves through the water by producing a traveling wave motion along the chord of their pectoral fin. Such a motion produces thrust through the development of an unsteady vortex street that results in a jet-like average flow. Digital particle image velocimetry (DPIV) is used to characterize the vortical patterns and structures developed in the wake of a manta ray-like fin. A DC servo motor powers a gear train to produce the traveling wave motion; whose frequency and wave length can be varied. The amplitude of the traveling wave motion linearly increases along the span of the fin. Wake morphologies for a wide spectrum of oscillation frequencies and traveling wave wavelengths are identified. A bifurcation from a 2S wake structure to a 2P wake structure is observed as the traveling wave wavelength is decreased, which corresponds to a decrease in efficiency as reported by Clark and Smits (2006). Alteration of the oscillation frequency, and thus Strouhal number, affects vortex interaction and is found to significantly modify the resulting velocity profiles in the wake of the fin. Notably, increasing the Strouhal number beyond optimal conditions, reported by Clark and Smits, corresponds to a reduction in the extent that the jet-like average flow is observed downstream of the fin.

  11. Pool boiling on rectangular fins with tunnel-pore structure

    Directory of Open Access Journals (Sweden)

    Pastuszko A.

    2013-04-01

    Full Text Available Complex experimental investigations were conducted in the area of pool boiling heat transfer on extended surfaces with internal tunnels limited by perforated foil. The experiments were carried out for water and R-123 at atmospheric pressure. The tunnel surfaces were fabricated from 0.05 – 0.1 mm thick perforated copper foil (pore diameters: 0.3, 0.4, 0.5 mm sintered with mini-fins formed by 5 and 10 mm high rectangular fins and horizontal inter-fin surface. The effect of the main fin height, pore diameters and tunnel pitch on nucleate pool boiling was examined. Substantial enhancement of heat transfer coefficient was observed for the investigated surfaces. The highest increase in the heat transfer coefficient was obtained for the 10 mm high fins – about 50kW/m2K for water and 15 kW/m2K for R-123. The investigated surfaces showed boiling heat transfer coefficients similar to those of existing tunnel-pore structures.

  12. Optimization of Internal Cooling Fins for Metal Hydride Reactors

    Directory of Open Access Journals (Sweden)

    Vamsi Krishna Kukkapalli

    2016-06-01

    Full Text Available Metal hydride alloys are considered as a promising alternative to conventional hydrogen storage cylinders and mechanical hydrogen compressors. Compared to storing in a classic gas tank, metal hydride alloys can store hydrogen at nearly room pressure and use less volume to store the same amount of hydrogen. However, this hydrogen storage method necessitates an effective way to reject the heat released from the exothermic hydriding reaction. In this paper, a finned conductive insert is adopted to improve the heat transfer in the cylindrical reactor. The fins collect the heat that is volumetrically generated in LaNi5 metal hydride alloys and deliver it to the channel located in the center, through which a refrigerant flows. A multiple-physics modeling is performed to analyze the transient heat and mass transfer during the hydrogen absorption process. Fin design is made to identify the optimum shape of the finned insert for the best heat rejection. For the shape optimization, use of a predefined transient heat generation function is proposed. Simulations show that there exists an optimal length for the fin geometry.

  13. Anisotropic flux pinning in high T{sub c} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kolesnik, S. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, PL-02668, Warszawa (Poland); Igalson, J. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, PL-02668, Warszawa (Poland); Skoskiewicz, T. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, PL-02668, Warszawa (Poland); Szymczak, R. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, PL-02668, Warszawa (Poland); Baran, M. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, PL-02668, Warszawa (Poland); Pytel, K. [Institute of Atomic Energy, Swierk (Poland); Pytel, B. [Institute of Atomic Energy, Swierk (Poland)

    1995-02-09

    In this paper we present a comparison of the results of FC magnetization measurements on several Pb-Sr-(Y,Ca)-Cu-O crystals representing various levels of flux pinning. The pinning centers in our crystals have been set up during the crystal growth process or introduced by neutron irradiation. Some possible explanations of the observed effects, including surface barrier, flux-center distribution and sample-shape effects, are discussed. ((orig.)).

  14. Investigating the interactions of yeast prions: [SWI+], [PSI+], and [PIN+].

    Science.gov (United States)

    Du, Zhiqiang; Li, Liming

    2014-06-01

    Multiple prion elements, which are transmitted as heritable protein conformations and often linked to distinct phenotypes, have been identified in the budding yeast, Saccharomyces cerevisiae. It has been shown that overproduction of a prion protein Swi1 can promote the de novo conversion of another yeast prion [PSI(+)] when Sup35 is co-overproduced. However, the mechanism underlying this Pin(+) ([PSI(+)] inducible) activity is not clear. Moreover, how the Swi1 prion ([SWI(+)]) interacts with other yeast prions is unknown. Here, we demonstrate that the Pin(+) activity associated with Swi1 overproduction is independent of Rnq1 expression or [PIN(+)] conversion. We also show that [SWI(+)] enhances the appearance of [PSI(+)] and [PIN(+)]. However, [SWI(+)] significantly compromises the Pin(+) activity of [PIN(+)] when they coexist. We further demonstrate that a single yeast cell can harbor three prions, [PSI(+)], [PIN(+)], and [SWI(+)], simultaneously. However, under this condition, [SWI(+)] is significantly destabilized. While the propensity to aggregate underlies prionogenesis, Swi1 and Rnq1 aggregates resulting from overproduction are usually nonheritable. Conversely, prion protein aggregates formed in nonoverexpressing conditions or induced by preexisting prion(s) are more prionogenic. For [PSI(+)] and [PIN(+)] de novo formation, heterologous "facilitators," such as preexisting [SWI(+)] aggregates, colocalize only with the newly formed ring-/rod-shaped Sup35 or Rnq1 aggregates, but not with the dot-shaped mature prion aggregates. Their colocalization frequency is coordinated with their prion inducibility, indicating that prion-prion interactions mainly occur at the early initiation stage. Our results provide supportive evidence for the cross-seeding model of prionogenesis and highlight a complex interaction network among prions in yeast.

  15. Open safety pin ingestion presenting as incarcerated umbilical hernia.

    Science.gov (United States)

    Mirza, Bilal; Sheikh, Afzal

    2011-09-01

    Foreign body ingestion is common in children. Sharp foreign bodies are potentially harmful and can result various complications. An 8-month-old infant presented with incarcerated umbilical hernia. With a suspicion of strangulation, operation was performed that revealed a loop of ileum being stuck in the umbilical defect. The loop of ileum was freed from the umbilicus which demonstrated open ends of safety pin piercing out of bowel lumen. The enterotomy followed by removal of safety pin was performed.

  16. Open Safety Pin Ingestion Presenting as Incarcerated Umbilical Hernia

    OpenAIRE

    Bilal Mirza; Afzal Sheikh

    2011-01-01

    Foreign body ingestion is common in children. Sharp foreign bodies are potentially harmful and can result various complications. An 8-month-old infant presented with incarcerated umbilical hernia. With a suspicion of strangulation, operation was performed that revealed a loop of ileum being stuck in the umbilical defect. The loop of ileum was freed from the umbilicus which demonstrated open ends of safety pin piercing out of bowel lumen. The enterotomy followed by removal of safety pin was p...

  17. Open Safety Pin Ingestion Presenting as Incarcerated Umbilical Hernia

    Directory of Open Access Journals (Sweden)

    Bilal Mirza

    2011-11-01

    Full Text Available Foreign body ingestion is common in children. Sharp foreign bodies are potentially harmful and can result various complications. An 8-month-old infant presented with incarcerated umbilical hernia. With a suspicion of strangulation, operation was performed that revealed a loop of ileum being stuck in the umbilical defect. The loop of ileum was freed from the umbilicus which demonstrated open ends of safety pin piercing out of bowel lumen. The enterotomy followed by removal of safety pin was performed.

  18. AtPIN: Arabidopsis thaliana Protein Interaction Network

    Directory of Open Access Journals (Sweden)

    Silva-Filho Marcio C

    2009-12-01

    Full Text Available Abstract Background Protein-protein interactions (PPIs constitute one of the most crucial conditions to sustain life in living organisms. To study PPI in Arabidopsis thaliana we have developed AtPIN, a database and web interface for searching and building interaction networks based on publicly available protein-protein interaction datasets. Description All interactions were divided into experimentally demonstrated or predicted. The PPIs in the AtPIN database present a cellular compartment classification (C3 which divides the PPI into 4 classes according to its interaction evidence and subcellular localization. It has been shown in the literature that a pair of genuine interacting proteins are generally expected to have a common cellular role and proteins that have common interaction partners have a high chance of sharing a common function. In AtPIN, due to its integrative profile, the reliability index for a reported PPI can be postulated in terms of the proportion of interaction partners that two proteins have in common. For this, we implement the Functional Similarity Weight (FSW calculation for all first level interactions present in AtPIN database. In order to identify target proteins of cytosolic glutamyl-tRNA synthetase (Cyt-gluRS (AT5G26710 we combined two approaches, AtPIN search and yeast two-hybrid screening. Interestingly, the proteins glutamine synthetase (AT5G35630, a disease resistance protein (AT3G50950 and a zinc finger protein (AT5G24930, which has been predicted as target proteins for Cyt-gluRS by AtPIN, were also detected in the experimental screening. Conclusions AtPIN is a friendly and easy-to-use tool that aggregates information on Arabidopsis thaliana PPIs, ontology, and sub-cellular localization, and might be a useful and reliable strategy to map protein-protein interactions in Arabidopsis. AtPIN can be accessed at http://bioinfo.esalq.usp.br/atpin.

  19. Film condensation of HCFC-123 on staggered bundles of horizontal finned tubes. Effect of fin geometry; Suihei fintsukikan no chidori kanbun ni okeru HCFC-123 no gyoshuku. Fin keijo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Takamatsu, H.; Takada, N. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study; Makishi, O. [Kyushu University, Fukuoka (Japan); Sejimo, H. [NKK Corp., Tokyo (Japan)

    1995-03-25

    Experiments were conducted to obtain row-by-row heat transfer data during condensation of downward flowing HCFC-123 vapor in staggered bundles of horizontal two-dimensional fin tubes. Two conventional low fin tubes and two finned tubes with fin shapes close to that of a new high-performance fin proposed by Zhu and Honda were tested. The latter tubes had fin dimensions that were optimized by theoretical analysis. The heat transfer characteristics were compared with previous results for in-line bundles of the same test tubes and with theoretical predictions for stagnant vapor. The decrease in heat transfer due to condensate inundation was less significant for the staggered tube bundle. The highest heat transfer coefficient was provided by the staggered bundle of one of the new finned tubes. The theoretical predictions compared well with experimental data at a low vapor velocity and a low to medium condensate inundation rate. 15 refs., 10 figs., 2 tabs.

  20. A Versatile Mixed-Signal Pin Approach for Cost-Effective Test of Automotive ICs

    Institute of Scientific and Technical Information of China (English)

    Credence Systems Corporation

    2004-01-01

    @@ (上接第9期51页) Figure 3:3 different pins types which cover a wide range of requirements: - DPIN: The digital mixed signal pin for high speed digital requirements - VPIN digital mixed-signal pin with high voltage digital test capability. With the 30 V swing and 50 MHz data rate the pin fits excellent for automotive requirements.

  1. Dipentamethylene thiuram monosulfide is a novel inhibitor of Pin1

    Energy Technology Data Exchange (ETDEWEB)

    Tatara, Yota; Lin, Yi-Chin; Bamba, Yoshimasa; Mori, Tadashi [Molecular Enzymology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Amamiya, Tsutsumidori, Aoba, Sendai, Miyagi 981-8555 (Japan); Uchida, Takafumi, E-mail: uchidat@biochem.tohoku.ac.jp [Molecular Enzymology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Amamiya, Tsutsumidori, Aoba, Sendai, Miyagi 981-8555 (Japan)

    2009-07-03

    Pin1 is involved in eukaryotic cell proliferation by changing the structure and function of phosphorylated proteins. PiB, the Pin1 specific inhibitor, blocks cancer cell proliferation. However, low solubility of PiB in DMSO has limited studies of its effectiveness. We screened for additional Pin1 inhibitors and identified the DMSO-soluble compound dipentamethylene thiuram monosulfide (DTM) that inhibits Pin1 activity with an EC50 value of 4.1 {mu}M. Molecular modeling and enzyme kinetic analysis indicated that DTM competitively inhibits Pin1 activity, with a K{sub i} value of 0.05 {mu}M. The K{sub D} value of DTM with Pin1 was determined to be 0.06 {mu}M by SPR technology. Moreover, DTM specifically inhibited peptidyl-prolyl cis/trans isomerase activity in HeLa cells. FACS analysis showed that DTM induced G0 arrest of the HCT116 cells. Our results suggest that DTM has the potential to guide the development of novel antifungal and/or anticancer drugs.

  2. Self-pinning of a nanosuspension droplet: Molecular dynamics simulations

    Science.gov (United States)

    Shi, Baiou; Webb, Edmund B.

    2016-07-01

    Results are presented from molecular dynamics simulations of Pb(l) nanodroplets containing dispersed Cu nanoparticles (NPs) and spreading on solid surfaces. Three-dimensional simulations are employed throughout, but droplet spreading and pinning are reduced to two-dimensional processes by modeling cylindrical NPs in cylindrical droplets; NPs have radius RNP≅3 nm while droplets have initial R0≅42 nm . At low particle loading explored here, NPs in sufficient proximity to the initial solid-droplet interface are drawn into advancing contact lines; entrained NPs eventually bind with the underlying substrate. For relatively low advancing contact angle θadv, self-pinning on entrained NPs occurs; for higher θadv, depinning is observed. Self-pinning and depinning cases are compared and forces on NPs at the contact line are computed during a depinning event. Though significant flow in the droplet occurs in close proximity to the particle during depinning, resultant forces are relatively low. Instead, forces due to liquid atoms confined between the particles and substrate dominate the forces on NPs; that is, for the NP size studied here, forces are interface dominated. For pinning cases, a precursor wetting film advances ahead of the pinned contact line but at a significantly slower rate than for a pure droplet. This is because the precursor film is a bilayer of liquid atoms on the substrate surface but it is instead a monolayer film as it crosses over pinning particles; thus, mass delivery to the bilayer structure is impeded.

  3. Pinned vortex hopping in a neutron star crust

    CERN Document Server

    Haskell, Brynmor

    2015-01-01

    The motion of superfluid vortices in a neutron star crust is at the heart of most theories of pulsar glitches. Pinning of vortices to ions can decouple the superfluid from the crust and create a reservoir of angular momentum. Sudden large scale unpinning can lead to an observable glitch. In this paper we investigate the scattering of a free vortex off a pinning potential and calculate its mean free path, in order to assess whether unpinned vortices can skip multiple pinning sites and come close enough to their neighbours to trigger avalanches, or whether they simply hop from one pinning site to another giving rise to a more gradual creep. We find that there is a significant range of parameter space in which avalanches can be triggered, thus supporting the hypothesis that they may lie at the origin of pulsar glitches. For realistic values of the pinning force and superfluid drag parameters we find that avalanches are more likely in the higher density regions of the crust where pinning is stronger. Physical dif...

  4. Dipentamethylene thiuram monosulfide is a novel inhibitor of Pin1.

    Science.gov (United States)

    Tatara, Yota; Lin, Yi-Chin; Bamba, Yoshimasa; Mori, Tadashi; Uchida, Takafumi

    2009-07-03

    Pin1 is involved in eukaryotic cell proliferation by changing the structure and function of phosphorylated proteins. PiB, the Pin1 specific inhibitor, blocks cancer cell proliferation. However, low solubility of PiB in DMSO has limited studies of its effectiveness. We screened for additional Pin1 inhibitors and identified the DMSO-soluble compound dipentamethylene thiuram monosulfide (DTM) that inhibits Pin1 activity with an EC50 value of 4.1 microM. Molecular modeling and enzyme kinetic analysis indicated that DTM competitively inhibits Pin1 activity, with a K(i) value of 0.05 microM. The K(D) value of DTM with Pin1 was determined to be 0.06 microM by SPR technology. Moreover, DTM specifically inhibited peptidyl-prolyl cis/trans isomerase activity in HeLa cells. FACS analysis showed that DTM induced G0 arrest of the HCT116 cells. Our results suggest that DTM has the potential to guide the development of novel antifungal and/or anticancer drugs.

  5. Development of colburn ` j' factor and fanning friction factor ` f' correlations for compact heat exchanger plain fins by using CFD

    Science.gov (United States)

    Bala Sundar Rao, R.; Ranganath, G.; Ranganayakulu, C.

    2013-07-01

    A numerical model has been developed for plain fin of plate fin heat exchanger. Plain fin performance has been analyzed with the help of CFD by changing the various parameters of the fin, Colburn ` j' and fanning friction ` f' factors are calculated. These values compared with the standard values. The correlations have been developed between Reynolds number Re, fin height h, fin thickness t, fin spacing s, Colburn factor ` j' and friction factor ` f'.

  6. Repeat biopsy in patients with initial diagnosis of PIN; La biopsia ripetuta nei pazienti con diagnosi iniziale di PIN

    Energy Technology Data Exchange (ETDEWEB)

    De Matteis, Massimo [Azienda Ospedaliera Policlinico S. Orsola-Malpighi, Bologna (Italy). UO Radiologia Albertoni; Poggi, Cristina; De Martino, Antonietta; Pavlica, Pietro [Azienda Ospedaliera Policlinico S. Orsola-Malpighi, Bologna (Italy). UO Radiologia Palagi, Dipartimento area radiologica; Corti, Barbara [Azienda Ospedaliera Policlinico S. Orsola-Malpighi, Bologna (Italy). UO Anatomia ed istologia patologica, Dipartimento oncologico ed ematologico; Barozzi, Libero [Azienda Ospedaliera Policlinico S. Orsola-Malpighi, Bologna (Italy). UO Radiologia d' urgenza, Dipartimento emergenze ed accettazione

    2005-09-15

    Purpose. Prostatic intra-epithelial neoplasia (PIN) is considered a pre-malignant lesion and the main precursor of invasive prostatic adenocarcinoma. A PIN diagnosis established by prostate needle biopsy poses a difficult clinical management. problem. We retrospectively reviewed our three-year experience in order to identify criteria for referring patients to repeat biopsy. Materials and methods. We reviewed the repeat biopsy records of 72 patients in whom PIN had been detected on initial US-guided needle biopsy of the prostate. All the patients had a minimum of 6 biopsy cores taken, and they all had PSA > 4 ng/ml. Results. Adenocarcinoma was detected in 15 patients out of 50 (30%) with an initial diagnosis of low-grade PIN and in 10 patients out of 22 (45.4%) with high grade PIN, in 7 out of 18 (39%) in whom PSA levels had decreased during the observation interval, in 16 patients out of 46 (35%) in whom the PSA had increased and in 2 patients out of 8 (25%) with stable PSA. Conclusions. Our results seem to confirm that PIN can be considered a precursor of prostatic adenocarcinoma or a histological alteration often associated with it. Patients with low-grade PIN and particularly those with high-grade PIN should be regularly subjected to repeat biopsy at short intervals due to the high frequency of the final diagnosis of carcinoma. No agreement has been reached on the time interval between the first and the second biopsy. The PSA changes during the observation period are not a statistically significant parameter to suggest the repetition of prostatic biopsy. [Italian] Scopo. La neoplasia prostatica intraepiteliale (PIN) e considerata una lesione premaligna ed il precursore principale dell'adenocarcinoma prostatico infiltrante. La diagnosi di PIN ottenuta con l'agobiopsia della prostata rappresenta un difficile problema gestionale clinico. In una valutazione retrospettiva della nostra esperienza di 3 anni si e cercato di individuare i criteri che possano

  7. Pin-Hole Luminosity Monitor with Feedback

    Science.gov (United States)

    Norem, James H.; Spencer, James E.

    Previously, the generalized luminosity { L} was defined and calculated for all incident channels based on an NLC e+e- design. Alternatives were then considered to improve the differing beam-beam effects in the e-e-, eγ and γγ channels. Regardless of the channel, there was a large flux of outgoing, high energy photons that were produced from the beam-beam interaction e.g. beamstrahlung that needs to be disposed of and whose flux depended on { L}. One approach to this problem is to consider it a resource and attempt to take advantage of it by disposing of these straight-ahead photons in more useful ways than simply dumping them. While there are many options for monitoring the luminosity, any method that allows feedback and optimization in real time and in a non-intercepting and non-interfering way during normal data taking is extremely important - especially if it provides other capabilities such as high resolution tuning of spot sizes and can be used for all incident channels without essential modifications to their setup. Our "pin-hole" camera appears to be such a device if it can be made to work with high energy photons in ways that are compatible with the many other constraints and demands on space around the interaction region. The basis for using this method is that it has, in principle, the inherent resolution and bandwidth to monitor the very small spot sizes and their stabilities that are required for very high, integrated luminosity. While there are many possible, simultaneous uses of these outgoing photon beams, we limit our discussion to a single, blind, proof-of-principle experiment that was done on the FFTB line at SLAC to certify the concept of a camera obscura for high energy photons.

  8. Interplay between collective pinning and artificial defects on domain wall propagation in Co/Pt multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Rodriguez, G; Hierro-Rodriguez, A; Perez-Junquera, A; Montenegro, N; Alameda, J M; Velez, M [Dept. Fisica, Universidad de Oviedo-CINN, 33007 Oviedo (Spain); Menendez, J L [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN). Principado de Asturias-Consejo Superior de Investigaciones Cientificas (CSIC)-Univ. Oviedo -UO, Parque Tecnologico de Asturias, 33428 Llanera (Spain); Ravelosona, D, E-mail: mvelez@uniovi.e [Institut d' Electronique Fondamentale, UMR CNRS 8622, Univ. Paris Sud, 91405 Orsay Cedex (France)

    2010-08-04

    The interplay between collective pinning on intrinsic structural defects and artificial pinning at a patterned hole is studied in magnetic multilayers with perpendicular anisotropy. The pinning strength of a patterned hole is measured through its efficiency to stop domain wall (DW) propagation into a consecutive unpatterned nanowire section (using antisymmetric magnetoresistance to detect the direction of DW propagation) whereas collective pinning is characterized by the field dependence of DW velocity. Close to room temperature, collective pinning becomes weaker than artificial pinning so that pinning at the hole compensates nucleation-pad geometry, blocking DW propagation across the nanowire.

  9. Global infinite energy solutions for the cubic wave equation

    OpenAIRE

    Burq, N.; L. Thomann; Tzvetkov, N.

    2012-01-01

    International audience; We prove the existence of infinite energy global solutions of the cubic wave equation in dimension greater than 3. The data is a typical element on the support of suitable probability measures.

  10. The Coulombic Lattice Potential of Ionic Compounds: The Cubic Perovskites.

    Science.gov (United States)

    Francisco, E.; And Others

    1988-01-01

    Presents coulombic models representing the particles of a system by point charges interacting through Coulomb's law to explain coulombic lattice potential. Uses rubidium manganese trifluoride as an example of cubic perovskite structure. Discusses the effects on cluster properties. (CW)

  11. Spinning solitons in cubic-quintic nonlinear media

    Indian Academy of Sciences (India)

    Lucian-Cornel Crasovan; Boris A Malomed; Dumitru Mihalache

    2001-11-01

    We review recent theoretical results concerning the existence, stability and unique features of families of bright vortex solitons (doughnuts, or ‘spinning’ solitons) in both conservative and dissipative cubic-quintic nonlinear media.

  12. Laser Welding Of Finned Tubes Made Of Austenitic Steels

    Directory of Open Access Journals (Sweden)

    Stolecki M.

    2015-09-01

    Full Text Available This paper describes the technology of welding of finned tubes made of the X5CrNi1810 (1.4301 austenitic steel, developed at Energoinstal SA, allowing one to get high quality joints that meet the requirements of the classification societies (PN-EN 15614, and at the same time to significantly reduce the manufacturing costs. The authors described an automatic technological line equipped with a Trumph disc laser and a tube production technological process. To assess the quality of the joints, one performed metallographic examinations, hardness measurements and a technological attempt to rupture the fin. Analysis of the results proved that the laser-welded finned tubes were performed correctly and that the welded joints had shown no imperfections.

  13. Heat transfer of smooth and finned tubes in A CFBC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B.H. [Korea Electric Power Research Institute, Taejeon (Korea); Cho, H.H. [Yonsei University, Seoul (Korea)

    2000-11-01

    The objective of present work is to investigate experimentally the characteristics of heat transfer. A fluidized bed combustion has advantages of pollution control, fuel flexibility and excellent heat transfer. The present study investigates fundamental phenomena of bed-to-surface heat transfer in high temperature fluidized beds to improve design of immersed tube surface. The tested operating variables are bed temperature, superficial velocity, mean size of bed material, and the rake angle of fin. Generally, heat transfer rates between the fluidized bed and immersed finned-tube are much higher than those of a smooth tube. A life time of finned-tube is generally longer than that of smooth tube. (author). 4 figs.

  14. A thermal study of pipes with outer transverse fins

    Directory of Open Access Journals (Sweden)

    S. Gil

    2016-10-01

    Full Text Available This paper provides results of thermal investigations on pipes with outer transverse fins produced by placing a strip, being a form of helical spring which functions as a radiator, on the basis pipe. The investigations were carried out at the facility that enables measurements with respect to both natural and forced convection. Performance of the investigated pipes was assessed in relation to a non-finned pipe and a pipe welded with the use of Metal Active Gas (MAG technology. The experiments have shown that the finned pipe welding technology does not markedly affect their thermal efficiency, which has been confirmed by performed model calculations, while the welding technology has a crucial impact on their operating performance.

  15. Development and evolution of the muscles of the pelvic fin.

    Directory of Open Access Journals (Sweden)

    Nicholas J Cole

    2011-10-01

    Full Text Available Locomotor strategies in terrestrial tetrapods have evolved from the utilisation of sinusoidal contractions of axial musculature, evident in ancestral fish species, to the reliance on powerful and complex limb muscles to provide propulsive force. Within tetrapods, a hindlimb-dominant locomotor strategy predominates, and its evolution is considered critical for the evident success of the tetrapod transition onto land. Here, we determine the developmental mechanisms of pelvic fin muscle formation in living fish species at critical points within the vertebrate phylogeny and reveal a stepwise modification from a primitive to a more derived mode of pelvic fin muscle formation. A distinct process generates pelvic fin muscle in bony fishes that incorporates both primitive and derived characteristics of vertebrate appendicular muscle formation. We propose that the adoption of the fully derived mode of hindlimb muscle formation from this bimodal character state is an evolutionary innovation that was critical to the success of the tetrapod transition.

  16. Boiling visualization on vertical fins with tunnel-pore structures

    Directory of Open Access Journals (Sweden)

    Kaniowski Robert

    2012-04-01

    Full Text Available The paper presents experimental studies of nucleate boiling heat transfer from a system of connected horizontal and vertical subsurface tunnels. The experiments were carried out for water at atmospheric pressure. The tunnel external covers were manufactured out of perforated copper foil (holes diameter 0.3 mm, sintered with the mini-fins, formed on the vertical side of the 10 mm high rectangular fins and horizontal inter-fin surface. The image acquisition speed was 493 fps (at resolution 400 × 300 pixels with Photonfocus PHOT MV-D1024-160-CL camera. Visualization investigations aimed to identify nucleation sites and flow patterns and to determine the bubble departure diameter and frequency at various superheats for vertical tunnels. At low superheat vapor bubbles are generated nearly exclusively by the vertical tunnel. At medium values of superheat, pores of the horizontal tunnel activate.

  17. Wake Vortex Structure Characteristics of a Flexible Oscillating Fin

    Institute of Scientific and Technical Information of China (English)

    Zhi-dong Wang; Pei Chen; Xiao-qing Zhang

    2008-01-01

    We compute the wake of a two-dimensional and three-dimensional flexible fin in an unsteady flow field with heaving and pitching motions using FLUENT. Deflexion mode is used for a non-uniform cantilever beam with non-uniformly distributed load. The effect of chordwise deflexion length on the characteristics of propulsion is discussed for two-dimensional flexible fin.The thrust coefficient decreases, propulsive efficiency increases and the intensity of turbulence attenuates gradually as the deflexion length increases. For a three-dimensional flexible fin, the intensity of the vortex in the plane of symmetry is higher than that in the plane at 3/4 span length of the caudal fro. But the propulsive performance achieved is not what we expected with the given deflexion mode.

  18. Efficiency of the unit cell in rectangular finned tube arrangements

    Energy Technology Data Exchange (ETDEWEB)

    Buzzoni, Luca; Dall' Olio, Roberto; Spiga, Marco [Bologna Univ., DIENCA, Bologna (Italy)

    1999-11-01

    This paper is aimed at presenting an investigation concerning the efficiency of the single unit in finned air-cooled heat exchangers with staggered and in-line bundles of rectangular ducts, where a hot process fluid flows inside extended-surface tubes and atmospheric air is circulated outside, over the extended surface. The differential energy equation is numerically solved by a finite difference technique, in order to determine the spatial temperature profiles, then the fin efficiency and the augmentation factor are calculated by a simple numerical integration. The results show that the temperature distribution and the fin performance depend on four dimensionless parameters (m,{beta},p{sub x},p{sub y}), the first accounting for the heat transfer condition, the other ones accounting for the geometry of the extended surface (tube aspect ratio and pitches). Several tables are presented, allowing the efficiency of the extended surface to be deduced as a function of the thermal and geometric parameters. (Author)

  19. Development and Evolution of the Muscles of the Pelvic Fin

    Science.gov (United States)

    Cole, Nicholas J.; Hall, Thomas E.; Don, Emily K.; Berger, Silke; Boisvert, Catherine A.; Neyt, Christine; Ericsson, Rolf; Joss, Jean; Gurevich, David B.; Currie, Peter D.

    2011-01-01

    Locomotor strategies in terrestrial tetrapods have evolved from the utilisation of sinusoidal contractions of axial musculature, evident in ancestral fish species, to the reliance on powerful and complex limb muscles to provide propulsive force. Within tetrapods, a hindlimb-dominant locomotor strategy predominates, and its evolution is considered critical for the evident success of the tetrapod transition onto land. Here, we determine the developmental mechanisms of pelvic fin muscle formation in living fish species at critical points within the vertebrate phylogeny and reveal a stepwise modification from a primitive to a more derived mode of pelvic fin muscle formation. A distinct process generates pelvic fin muscle in bony fishes that incorporates both primitive and derived characteristics of vertebrate appendicular muscle formation. We propose that the adoption of the fully derived mode of hindlimb muscle formation from this bimodal character state is an evolutionary innovation that was critical to the success of the tetrapod transition. PMID:21990962

  20. Effect of Fin-Collar Shape at Contact Area between Tube and Fin on Heat Exchanger Performance

    Science.gov (United States)

    Matsuo, Yoshimi; Tsubaki, Koutaro; Miyara, Akio

    In this study, numerical simulation of a cross fin-tube heat exchanger was conducted to investigate the effects of fin-collar shape on the heat transfer performance and pressure drop. During the making process, two adjacent fin-collars and a tube form a triangular space and the end of fin collar protrude to air side. To investigate these effects on the heat exchanger performance, the form ratio was defined to make an indicator of the triangular space size. Furthermore, the simulation of the models with and without protruded end was conducted. The results indicated that the increase of the form ratio results in the decrease in the heat transfer rate. On the other hand, it contributed to a relatively small increase in the heat transfer coefficient on the air side. A high heat transfer coefficient on the air side was obtained by the protruded fin-collar end. However, the pressure drop was not much different between the models with and without the protruded end. The ratio of the thermal contact resistance to the air side thermal resistance was about 1:5 for the form ratio of 20% to 40%.

  1. Stress Intensity of Antiplane Conjugate Cracks in Cubic Quasicrystal

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei

    2008-01-01

    Based on the theory of Muskhelishvili, the general solutions for stress and strain of conjugate cracks in cubic quasicrystal are obtained, with which the stress intensity factors of cubic quasicrystal at crack tips and the stress distribution functions of phonon and phason fields are given. The results show that though phason field is coupled with phonon field by constitutive equations, the stress intensity factors are not coupled with any other factors.

  2. Optical studies of cubic III-nitride structures

    OpenAIRE

    Powell, Ross E L

    2014-01-01

    The properties of cubic nitrides grown by molecular beam epitaxy (MBE) on GaAs (001) have been studied using optical and electrical techniques. The aim of these studies was the improvement of the growth techniques in order to improve the quality of grown nitrides intended for bulk substrate and optoelectronic device applications. We have also characterised hexagonal nanocolumn structures incorporating indium. Firstly, bulk films of cubic AlxGa1-xN with aluminium fractions (x) spanning the ...

  3. Atom-probe for FinFET dopant characterization.

    Science.gov (United States)

    Kambham, A K; Mody, J; Gilbert, M; Koelling, S; Vandervorst, W

    2011-05-01

    With the continuous shrinking of transistors and advent of new transistor architectures to keep in pace with Moore's law and ITRS goals, there is a rising interest in multigate 3D-devices like FinFETs where the channel is surrounded by gates on multiple surfaces. The performance of these devices depends on the dimensions and the spatial distribution of dopants in source/drain regions of the device. As a result there is a need for new metrology approach/technique to characterize quantitatively the dopant distribution in these devices with nanometer precision in 3D. In recent years, atom probe tomography (APT) has shown its ability to analyze semiconductor and thin insulator materials effectively with sub-nm resolution in 3D. In this paper we will discuss the methodology used to study FinFET-based structures using APT. Whereas challenges and solutions for sample preparation linked to the limited fin dimensions already have been reported before, we report here an approach to prepare fin structures for APT, which based on their processing history (trenches filled with Si) are in principle invisible in FIB and SEM. Hence alternative solutions in locating and positioning them on the APT-tip are presented. We also report on the use of the atom probe results on FinFETs to understand the role of different dopant implantation angles (10° and 45°) when attempting conformal doping of FinFETs and provide a quantitative comparison with alternative approaches such as 1D secondary ion mass spectrometry (SIMS) and theoretical model values.

  4. Role of the Arabidopsis PIN6 Auxin Transporter in Auxin Homeostasis and Auxin-Mediated Development

    OpenAIRE

    2013-01-01

    Plant-specific PIN-formed (PIN) efflux transporters for the plant hormone auxin are required for tissue-specific directional auxin transport and cellular auxin homeostasis. The Arabidopsis PIN protein family has been shown to play important roles in developmental processes such as embryogenesis, organogenesis, vascular tissue differentiation, root meristem patterning and tropic growth. Here we analyzed roles of the less characterised Arabidopsis PIN6 auxin transporter. PIN6 is auxin-inducible...

  5. THE PROPERTIES AND MICROSTRUCTURE OF NB-47TI SUPERCONDUCTOR WITH MAGNETIC PINNING CENTERS.

    Energy Technology Data Exchange (ETDEWEB)

    MOTOWIDLO,L.R.RUDZIAK,M.D.WONG,T.COOLEY,L.D.LEE,P.J.

    2004-02-04

    We have investigated Nb-47Ti multifilament wire with artificial pinning centers (APC). The superconducting properties and proximity effect in wires with ferromagnetic and non-magnetic pins will be discussed. Magnetization and transport measurements will be presented and the pinning characteristics will be discussed as a function of magnetic field, temperature and volume percent pins. In addition, field emission scanning electron microscopy of the pin nanostructure will be presented.

  6. Investigation of Heat Transfer Through Fins Using Fem

    Directory of Open Access Journals (Sweden)

    Mr. H.N. Gandate

    2014-10-01

    Full Text Available Analysis of heat distribution, thermal stresses and strain for engine cylinder and fins are discussed in this paper. The cylinder and fins being analysed using finite (FE software ANSYS AND by FE (simple model. When a cylinder is subjected to certain pressure and temperature thermal distribution and thermal stresses analysis of cylinder is necessary to avoid the failure during working condition. In this work the temperature distribution and thermal stresses are evaluated by considering only temperature effect, temperature and gas pressure effect and also evaluate the same by considering the effect of cylinder head.

  7. Atom-probe for FinFET dopant characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kambham, A.K., E-mail: kambham@imec.be [K.U.Leuven, Instituut voor Kern-en Stralings fysika, Celestijnenlaan 200D, B-3001, Leuven (Belgium); IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Mody, J.; Gilbert, M.; Koelling, S.; Vandervorst, W. [K.U.Leuven, Instituut voor Kern-en Stralings fysika, Celestijnenlaan 200D, B-3001, Leuven (Belgium); IMEC, Kapeldreef 75, B-3001 Leuven (Belgium)

    2011-05-15

    With the continuous shrinking of transistors and advent of new transistor architectures to keep in pace with Moore's law and ITRS goals, there is a rising interest in multigate 3D-devices like FinFETs where the channel is surrounded by gates on multiple surfaces. The performance of these devices depends on the dimensions and the spatial distribution of dopants in source/drain regions of the device. As a result there is a need for new metrology approach/technique to characterize quantitatively the dopant distribution in these devices with nanometer precision in 3D. In recent years, atom probe tomography (APT) has shown its ability to analyze semiconductor and thin insulator materials effectively with sub-nm resolution in 3D. In this paper we will discuss the methodology used to study FinFET-based structures using APT. Whereas challenges and solutions for sample preparation linked to the limited fin dimensions already have been reported before, we report here an approach to prepare fin structures for APT, which based on their processing history (trenches filled with Si) are in principle invisible in FIB and SEM. Hence alternative solutions in locating and positioning them on the APT-tip are presented. We also report on the use of the atom probe results on FinFETs to understand the role of different dopant implantation angles (10{sup o} and 45{sup o}) when attempting conformal doping of FinFETs and provide a quantitative comparison with alternative approaches such as 1D secondary ion mass spectrometry (SIMS) and theoretical model values. -- Research highlights: {yields} This paper provides the information on how to characterize the FinFET devices using atom probe tomography (APT). {yields} Importance of this work is to assess the performance of these devices at different processing conditions by extracting the compositional profiles. {yields} The performance of these devices depends on the dimensions and the spatial distribution of dopants in source/drain regions

  8. FLOW DISTRIBUTION IN A SOLAR COLLECTOR PANEL WITH HORIZONTAL FINS

    DEFF Research Database (Denmark)

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2005-01-01

    (CFD) calculations. Further, experimental investigations of a 12.5 m² solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured......The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontal fins. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid dynamics...

  9. Finned tubes for heat exchangers: Characterization and performance simulation

    Energy Technology Data Exchange (ETDEWEB)

    Armand, J.-L.; Molle, N. (Centre Tecnique des Industries Aerauliques et Thermiques (CETIAT), 75 Paris (France))

    1992-06-01

    Relevant to air conditioning applications, the state-of-the-art of finned tube heat exchanger design is reviewed. The review covers the key design, performance and operation characteristics, as well as, principal heat transfer correlations for exchangers adopting 'dry' (without condensation) and 'wet' operation. External side heat transfer and pressure drop calculation methods are established for the characterization of external surfaces. For internal surfaces, correlations are given for two-phase flow and pressure drop. Reference is made to the NTU and CANUT simulation codes for the determination of optimum finned tube geometries for standard and particular operating conditions.

  10. Validation of a Model for Ice Formation around Finned Tubes

    Directory of Open Access Journals (Sweden)

    Kamal A. R. Ismai

    2016-09-01

    Full Text Available Phase change materials although attaractive option for thermal storage applications its main drawback is the slow thermal response during charging and discharging processes due to their low thermal conductivity. The present study validates a model developed by the authors some years ago on radial fins as a method to meliorate the thermal performance of PCM in horizontal storage system. The developed model for the radial finned tube is based on pure conduction, the enthalpy approach and was discretized by the finite difference method. Experiments were realized specifically to validate the model and its numerical predictions.

  11. Integral finned heater and cooler for stirling engines

    Science.gov (United States)

    Corey, John A.

    1984-01-01

    A piston and cylinder for a Stirling engine and the like having top and bottom meshing or nesting finned conical surfaces to provide large surface areas in close proximity to the working gas for good thermal (addition and subtraction of heat) exchange to the working gas and elimination of the usual heater and cooler dead volume. The piston fins at the hot end of the cylinder are perforated to permit the gas to pass into the piston interior and through a regenerator contained therein.

  12. Net Shape Fins for Compact Heat Exchanger Produced by Cold Spray

    Science.gov (United States)

    Cormier, Yannick; Dupuis, Philippe; Jodoin, Bertrand; Corbeil, Antoine

    2013-10-01

    This work explores the manufacturability of pyramidal fin arrays produced using the cold spray process. Near-net shaped pyramidal fin arrays of various sizes and fin densities were manufactured using masks made of commercially available steel wire mesh. The feedstock powders used to produce the fins are characterized using scanning electron microscopy. Obstruction of the masks was investigated. The standoff distances between the substrate, mesh, and nozzle were empirically determined. Fin array characterization was performed using digital microscopy. The fin arrays' heat transfer performance was assessed experimentally for a range of Reynolds number relevant to the application sought. The fins produced using the cold spray process outperform traditional straight (rectangular) fins at the same fin density and it is hypothesized that this is due to increased fluid mixing and turbulence.

  13. Formation mechanism of external finned tubes by extrusion-plough method

    Institute of Scientific and Technical Information of China (English)

    TANG Yong; LU Long-sheng; PAN Min-qing; LIU Xiao-kang; LIU Xiao-qing

    2006-01-01

    The formation mechanism of bulge on the work's surface during the extrusion process was analyzed. The bulge's size and the reasons for abscission were studied. The results show that the abscission of bulge from works is resulted from the integrated actions of pressure and friction between the plough tool and works. During the extrusion-plough process, it is noticed that four kinds of fins are appeared, which are gestation fin, multi-dimensional fin, tumor and overlap fin, when using different machining parameters. And multi-dimensional fin which has high heat transmission efficiency is a kind of complicated fin with cockscomb-like 3D substructure fin on the tip of 3D macrostructure fin. Based on the studies of those four kinds of fins, the conditions of their formation are concluded, as well as the formation mechanism is obtained.

  14. Spinor bose gases in cubic optical lattice

    Energy Technology Data Exchange (ETDEWEB)

    Mobarak, Mohamed Saidan Sayed Mohamed

    2014-01-27

    In recent years the quantum simulation of condensed-matter physics problems has resulted from exciting experimental progress in the realm of ultracold atoms and molecules in optical lattices. In this thesis we analyze theoretically a spinor Bose gas loaded into a three-dimensional cubic optical lattice. In order to account for different superfluid phases of spin-1 bosons with a linear Zeeman effect, we work out a Ginzburg-Landau theory for the underlying spin-1 Bose-Hubbard model. To this end we add artificial symmetry-breaking currents to the spin-1 Bose-Hubbard Hamiltonian in order to break the global U (1) symmetry. With this we determine a diagrammatic expansion of the grand-canonical free energy up to fourth order in the symmetry-breaking currents and up to the leading non-trivial order in the hopping strength which is of first order. As a cross-check we demonstrate that the resulting grand-canonical free energy allows to recover the mean-field theory. Applying a Legendre transformation to the grand-canonical free energy, where the symmetry-breaking currents are transformed to order parameters, we obtain the effective Ginzburg-Landau action. With this we calculate in detail at zero temperature the Mott insulator-superfluid quantum phase boundary as well as condensate and particle number density in the superfluid phase. We find that both mean-field and Ginzburg-Landau theory yield the same quantum phase transition between the Mott insulator and superfluid phases, but the range of validity of the mean-field theory turns out to be smaller than that of the Ginzburg-Landau theory. Due to this finding we expect that the Ginzburg-Landau theory gives better results for the superfluid phase and, thus, we restrict ourselves to extremize only the effective Ginzburg-Landau action with respect to the order parameters. Without external magnetic field the superfluid phase is a polar (ferromagnetic) state for anti-ferromagnetic (ferromagnetic) interactions, i.e. only the

  15. Flux Pinning in Superconducting Niobium-Titanium Alloys

    Science.gov (United States)

    McKinnell, James Charles

    1990-01-01

    By studying Nb-Ti alloys from Nb44wt%Ti to Nb62wt%Ti the low field (2T) current density has been raised from 6500A/mm^2 (4.2^ circK) with standard Nb46.5wt%Ti to 7400A/mm ^2 with Nb58wt%Ti. When standard processing sequences were used, the alloys containing more than 46.5wt%Ti exhibited non-uniform microstructures following a precipitation heat treatment and the hardness rose from 200 DPN to over 300 DPN. By increasing the cold work prior to heat treatment the non-uniform precipitation was avoided. The amount of cold work needed prior to heat treatment to suppress non-uniform precipitation increased as the Ti content of the alloy increased. The volume fraction of precipitate produced during a given heat treatment also increased as the Ti content of the alloy increased. As the Ti content increased, the peak in the reduced pinning force curve shifted from b = 0.5 to b = 0.25. In order to determine whether the change in the flux pinning properties was due to the change in microstructure or due to enhanced Delta H_{c} pinning as the Ti content was increased, a set of wires with similar microstructures was developed. Their flux pinning behavior showed that the higher Ti alloys have pinning force curves which peak at progressively lower reduced fields. Thus Delta H_{c} pinning becomes the dominant pinning mechanism as the Ti content is increased.

  16. Necropsy report of a fin whale (Balaenoptera physalus) stranded in Denmark in 2010

    DEFF Research Database (Denmark)

    Alstrup, Aage K. O.; Hedayat, Abdi; Jensen, Trine Hammer;

    2013-01-01

    There is little detailed information on stranded fin whales (Balaenoptera physalus) in the scientific literature (Notarbartolo di Sciara et al., 2003). In Denmark, at least eight fin whales stranded between the years 1603 and 1958 (Kinze, 1995). On 16 June 2010, a live subadult or adult male fin...... whale stranded in the Bay of Vejle (55º 69' N, 9º 58' E), Denmark. Despite several attempts, it was not possible to rescue the fin whale, which was only partially exposed by the water. The fin whale succumbed after 5 d stranded in shallow water. The dead fin whale was transported to a nearby pier...

  17. DSA patterning options for FinFET formation at 7nm node

    Science.gov (United States)

    Liu, Chi-Chun C.; Franke, Elliott; Lie, Fee Li; Sieg, Stuart; Tsai, Hsinyu; Lai, Kafai; Truong, Hoa; Farrell, Richard; Somervell, Mark; Sanders, Daniel; Felix, Nelson; Guillorn, Michael; Burns, Sean; Hetzer, David; Ko, Akiteru; Arnold, John; Colburn, Matthew

    2016-03-01

    Several 27nm-pitch directed self-assembly (DSA) processes targeting fin formation for FinFET device fabrication are studied in a 300mm pilot line environment, including chemoepitaxy for a conventional Fin arrays, graphoepitaxy for a customization approach and a hybrid approach for self-aligned Fin cut. The trade-off between each DSA flow is discussed in terms of placement error, Fin CD/profile uniformity, and restricted design. Challenges in pattern transfer are observed and process optimization are discussed. Finally, silicon Fins with 100nm depth and on-target CD using different DSA options with either lithographic or self-aligned customization approach are demonstrated.

  18. Necropsy report of a fin whale (Balaenoptera physalus) stranded in Denmark in 2010

    DEFF Research Database (Denmark)

    Alstrup, Aage K. O.; Hedayat, Abdi; Jensen, Trine Hammer

    2013-01-01

    There is little detailed information on stranded fin whales (Balaenoptera physalus) in the scientific literature (Notarbartolo di Sciara et al., 2003). In Denmark, at least eight fin whales stranded between the years 1603 and 1958 (Kinze, 1995). On 16 June 2010, a live subadult or adult male fin...... whale stranded in the Bay of Vejle (55º 69' N, 9º 58' E), Denmark. Despite several attempts, it was not possible to rescue the fin whale, which was only partially exposed by the water. The fin whale succumbed after 5 d stranded in shallow water. The dead fin whale was transported to a nearby pier...

  19. Fluid flow and heat transfer of a power-law fluid in an internally finned tube with different fin lengths

    Science.gov (United States)

    Grabski, Jakub Krzysztof; Kołodziej, Jan Adam

    2016-06-01

    In the paper an analysis of fluid flow and heat transfer of a power-law fluid in an internally finned tube with different fin length is conducted. Nonlinear momentum equation of a power-law fluid flow and nonlinear energy equation are solved using the Picard iteration method. Then on each iteration step the solution of inhomogeneous equation consists of two parts: the general solution and the particular solution. Firstly the particular solution is obtained by interpolation of the inhomogeneous term by means of the radial basis functions and monomials. Then the general solution is obtained using the method of fundamental solutions and by fulfilling boundary conditions.

  20. Alpha particles spectrometer with photodiode PIN; Espectrometro de particulas alfa con fotodiodo PIN

    Energy Technology Data Exchange (ETDEWEB)

    Chacon R, A.; Hernandez V, R.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidades Academicas de Estudios Nucleares e Ingenieria Electrica, Calle Cipres No. 10, Fracc. La Penuela, 09869 Zacatecas (Mexico); Ramirez G, J. [Instituto Nacional de Estadistica Geografia e Informatica, Direccion General de Innovacion y Tecnologia de Informacion, Av. Heroes de Nacozari Sur 2301, Fracc. Jardines del Parque, 20276 Aguascalientes (Mexico)], e-mail: achruiz@hotmail.com

    2009-10-15

    The radiation propagates in form of electromagnetic waves or corpuscular radiation; if the radiation energy causes ionization in environment that crosses it is considered ionizing radiation. To detect radiation several detectors types are used, if the radiation are alpha particles are used detectors proportional type or trace elements. In this work the design results, construction and tests of an alpha particles spectrometer are presented, which was designed starting from a photodiode PIN type. The system design was simulated with a code for electronic circuits. With results of simulation phase was constructed the electronic phase that is coupled to a multichannel analyzer. The resulting electronic is evaluated analyzing the electronic circuit performance before an alphas triple source and alpha radiation that produce two smoke detectors of domestic use. On the tests phase we find that the system allows obtain, in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  1. Heat exchanger with helical bundles of finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Eyking, H.J.

    1975-01-23

    The invention applies to a heat exchanger with helical bundles of tubes consisting of finned tubes separated by spacers. The spacers are designed as closed holding cylinders with holding devices for the tube bundles, each ot which surrounds a bundle of tubes. This construction serves to simplify the production process and to enable the use of the heat exchanger at higher loads.

  2. Zebrafish fin regeneration after cryoinjury-induced tissue damage

    Directory of Open Access Journals (Sweden)

    Bérénice Chassot

    2016-06-01

    Full Text Available Although fin regeneration following an amputation procedure has been well characterized, little is known about the impact of prolonged tissue damage on the execution of the regenerative programme in the zebrafish appendages. To induce histolytic processes in the caudal fin, we developed a new cryolesion model that combines the detrimental effects of freezing/thawing and ischemia. In contrast to the common transection model, the damaged part of the fin was spontaneously shed within two days after cryoinjury. The remaining stump contained a distorted margin with a mixture of dead material and healthy cells that concomitantly induced two opposing processes of tissue debris degradation and cellular proliferation, respectively. Between two and seven days after cryoinjury, this reparative/proliferative phase was morphologically featured by displaced fragments of broken bones. A blastemal marker msxB was induced in the intact mesenchyme below the damaged stump margin. Live imaging of epithelial and osteoblastic transgenic reporter lines revealed that the tissue-specific regenerative programmes were initiated after the clearance of damaged material. Despite histolytic perturbation during the first week after cryoinjury, the fin regeneration resumed and was completed without further alteration in comparison to the simple amputation model. This model reveals the powerful ability of the zebrafish to restore the original appendage architecture after the extended histolysis of the stump.

  3. Zebrafish Fins as a Model System for Skeletal Human Studies

    Directory of Open Access Journals (Sweden)

    Manuel Marí-Beffa

    2007-01-01

    Full Text Available Recent studies on the morphogenesis of the fins of Danio rerio (zebrafish during development and regeneration suggest that a number of inductive signals involved in the process are similar to some of those that affect bone and cartilage differentiation in mammals and humans. Akimenko et al. (2002 has shown that bone morphogenetic protein-2b (BMP2b is involved in the induction of dermal bone differentiation during fin regeneration. Many other groups have also shown that molecules from the transforming growth factor-beta superfamily (TGFβ, including BMP2, are effective in promoting chondrogenesis and osteogenesis in vivo in higher vertebrates, including humans. In the present study, we review the state of the art of this topic by a comparative analysis of skeletal tissue development, regeneration and renewal processes in tetrapods, and fin regeneration in fishes. A general conclusion of this study states that lepidotrichia is a special skeletal tissue different to cartilage, bone, enamel, or dentine in fishes, according to its extracellular matrix (ECM composition. However, the empirical analysis of inducing signals of skeletal tissues in fishes and tetrapods suggests that lepidotrichia is different to any responding features with main skeletal tissues. A number of new inductive molecules are arising from fin development and regeneration studies that might establish an empirical basis for further molecular approaches to mammal skeletal tissues differentiation. Despite the tissue dissimilarity, this empirical evidence might finally lead to clinical applications to skeletal disorders in humans.

  4. The Linear and Nonlinear Electro-MechanicalFin Actuator

    Directory of Open Access Journals (Sweden)

    Zeina A. Abdul Redha

    2011-01-01

    Full Text Available Electromechanical actuators are used in a wide variety of aerospace applications such as missiles, aircrafts and spy-fly etc. In this work a linear and nonlinear fin actuator mathematical model has been developed and its response is investigated by developing an algorithm for the system using MATLAB. The algorithm used to the linear model is the state space algorithm while the algorithm used to the nonlinear model is the discrete algorithm. The huge moment constant is varied from (-3000 to 3000 and the damping ratio is varied from (0.4 to 0.8. The comparison between linear and nonlinear fin actuator response results shows that for linear model, the maximum overshoot is about 10%, rising time is 0.23 sec. and steady state occur at 0.51 sec., while For nonlinear model the maximum overshoot is about 5%, rising time is 0.26 sec. and steady state occurs at 2 sec.; i.e., the nonlinear fin actuator system gives faster and more accurate response than does the linear fin actuator system.

  5. Biofluiddynamic scaling of flapping, spinning and translating fins and wings

    NARCIS (Netherlands)

    Lentink, D.; Dickinson, M.H.

    2009-01-01

    Organisms that swim or fly with fins or wings physically interact with the surrounding water and air. The interactions are governed by the morphology and kinematics of the locomotory system that form boundary conditions to the Navier–Stokes (NS) equations. These equations represent Newton's law of m

  6. Compensation of airflow maldistribution in fin-and-tube evaporators

    DEFF Research Database (Denmark)

    Kærn, Martin Ryhl; Tiedemann, Thomas

    2012-01-01

    Compensation of airflow maldistribution in fin-and tube evaporators for residential air-conditioning is investigated with regards to circuitry design and control of individual channel superheats. In particularly, the interlaced and the face split circuitry designs are compared numerically using...

  7. Novel FinFET Device Using Asymmetric Doping

    DEFF Research Database (Denmark)

    Moradi, Farshad

    2012-01-01

    In this paper, a new technique is proposed to improve the device characteristics by introducing asymmetric doping at the source and the drain of the conventional FinFET. Specifically, the proposed device exhibits 9X increase of the Ion/Ioff ratio and 3X improved DIBL compared to conventional...

  8. Pin1 and neurodegeneration: a new player for prion disorders?

    Directory of Open Access Journals (Sweden)

    Elisa Isopi

    2015-07-01

    Full Text Available Pin1 is a peptidyl-prolyl isomerase that catalyzes the cis/trans conversion of phosphorylated proteins at serine or threonine residues which precede a proline. The peptidyl-prolyl isomerization induces a conformational change of the proteins involved in cell signaling process. Pin1 dysregulation has been associated with some neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and Huntington's disease. Proline-directed phosphorylation is a common regulator of these pathologies and a recent work showed that it is also involved in prion disorders. In fact, prion protein phosphorylation at the Ser-43-Pro motif induces prion protein conversion into a disease-associated form. Furthermore, phosphorylation at Ser-43-Pro has been observed to increase in the cerebral spinal fluid of sporadic Creutzfeldt-Jakob Disease patients. These findings provide new insights into the pathogenesis of prion disorders, suggesting Pin1 as a potential new player in the disease. In this paper, we review the mechanisms underlying Pin1 involvement in the aforementioned neurodegenerative pathologies focusing on the potential role of Pin1 in prion disorders.

  9. Exchange anisotropy pinning of a standing spin-wave mode

    Science.gov (United States)

    Magaraggia, R.; Kennewell, K.; Kostylev, M.; Stamps, R. L.; Ali, M.; Greig, D.; Hickey, B. J.; Marrows, C. H.

    2011-02-01

    Standing spin waves in a thin film are used as sensitive probes of interface pinning induced by an antiferromagnet through exchange anisotropy. Using coplanar waveguide ferromagnetic resonance, pinning of the lowest energy spin-wave thickness mode in Ni80Fe20/Ir25Mn75 exchange-biased bilayers was studied for a range of Ir25Mn75 thicknesses. We show that pinning of the standing mode can be used to amplify, relative to the fundamental resonance, frequency shifts associated with exchange bias. The shifts provide a unique “fingerprint” of the exchange bias and can be interpreted in terms of an effective ferromagnetic film thickness and ferromagnet-antiferromagnet interface anisotropy. Thermal effects are studied for ultrathin antiferromagnetic Ir25Mn75 thicknesses, and the onset of bias is correlated with changes in the pinning fields. The pinning strength magnitude is found to grow with cooling of the sample, while the effective ferromagnetic film thickness simultaneously decreases. These results suggest that exchange bias involves some deformation of magnetic order in the interface region.

  10. A Flux-Pinning Mechanism for Segment Assembly and Alignment

    Science.gov (United States)

    Gersh-Range, Jessica A.; Arnold, William R.; Peck, Mason A.; Stahl, H. Philip

    2011-01-01

    Currently, the most compelling astrophysics questions include how planets and the first stars formed and whether there are protostellar disks that contain large organic molecules. Although answering these questions requires space telescopes with apertures of at least 10 meters, such large primaries are challenging to construct by scaling up previous designs; the limited capacity of a launch vehicle bounds the maximum diameter of a monolithic primary, and beyond a certain size, deployable telescopes cannot fit in current launch vehicle fairings. One potential solution is connecting the primary mirror segments edgewise using flux-pinning mechanisms, which are analogous to non-contacting damped springs. In the baseline design, a flux-pinning mechanism consists of a magnet and a superconductor separated by a predetermined gap, with the damping adjusted by placing aluminum near the interface. Since flux pinning is possible only when the superconductor is cooled below a critical temperature, flux-pinning mechanisms are uniquely suited for cryogenic space telescopes. By placing these mechanisms along the edges of the mirror segments, a primary can be built up over time. Since flux pinning requires no mechanical deployments, the assembly process could be robotic or use some other non-contacting scheme. Advantages of this approach include scalability and passive stability.

  11. Pin1 inhibitor Juglone prevents diabetic vascular dysfunction.

    Science.gov (United States)

    Costantino, Sarah; Paneni, Francesco; Lüscher, Thomas F; Cosentino, Francesco

    2016-01-15

    Atherosclerosis is a major cause of mortality in patients with diabetes. However, novel breakthrough therapies have yet to be approved in this setting. Prolyl-isomerase-1 (Pin1) is emerging as a key molecule implicated in vascular oxidative stress and inflammation. In the present study, we investigate whether pharmacological inhibition of Pin1 may protect against diabetes-induced oxidative stress, endothelial dysfunction and vascular inflammation. Experiments were performed in human aortic endothelial cells (HAECs) exposed to normal (5 mmol/L) or high glucose (25 mmol/L) concentrations, in the presence of Pin1 inhibitor Juglone (10 μM) or vehicle (kB-dependent inflammatory signatures were determined both in HAECs and aortas from diabetic mice. In HAECs, ambient hyperglycemia increased mitochondrial superoxide anion generation while treatment with Juglone prevented this phenomenon. Pharmacological inhibition of Pin1 also preserved mitochondrial integrity, nitric oxide availability and endothelial expression of adhesion molecules. Interestingly enough, endothelial dysfunction, oxidative stress and NF-kB-driven inflammation were significantly attenuated in diabetic mice chronically treated with Juglone as compared to vehicle-treated animals. Pharmacological inhibition of Pin1 by Juglone prevents hyperglycemia-induced vascular dysfunction. Taken together, our findings may set the stage for novel therapeutic approaches to prevent vascular complications in patients with diabetes. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Posttranslational modification and trafficking of PIN auxin efflux carriers.

    Science.gov (United States)

    Löfke, Christian; Luschnig, Christian; Kleine-Vehn, Jürgen

    2013-01-01

    Cell-to-cell communication is absolutely essential for multicellular organisms. Both animals and plants use chemicals called hormones for intercellular signaling. However, multicellularity of plants and animals has evolved independently, which led to establishment of distinct strategies in order to cope with variations in an ever-changing environment. The phytohormone auxin is crucial to plant development and patterning. PIN auxin efflux carrier-driven polar auxin transport regulates plant development as it controls asymmetric auxin distribution (auxin gradients), which in turn modulates a wide range of developmental processes. Internal and external cues trigger a number of posttranslational PIN auxin carrier modifications that were demonstrated to decisively influence variations in adaptive growth responses. In this review, we highlight recent advances in the analysis of posttranslational modification of PIN auxin efflux carriers, such as phosphorylation and ubiquitylation, and discuss their eminent role in directional vesicle trafficking, PIN protein de-/stabilization and auxin transport activity. We conclude with updated models, in which we attempt to integrate the mechanistic relevance of posttranslational modifications of PIN auxin carriers for the dynamic nature of plant development.

  13. Silicide Schottky Contacts to Silicon: Screened Pinning at Defect Levels

    Energy Technology Data Exchange (ETDEWEB)

    Drummond, T.J.

    1999-03-11

    Silicide Schottky contacts can be as large as 0.955 eV (E{sub v} + 0.165 eV) on n-type silicon and as large as 1.05 eV (E{sub c} {minus} 0.07 eV) on p-type silicon. Current models of Schottky barrier formation do not provide a satisfactory explanation of occurrence of this wide variation. A model for understanding Schottky contacts via screened pinning at defect levels is presented. In the present paper it is shown that most transition metal silicides are pinned approximately 0.48 eV above the valence band by interstitial Si clusters. Rare earth disilicides pin close to the divacancy acceptor level 0.41 eV below the conduction band edge while high work function silicides of Ir and Pt pin close to the divacancy donor level 0.21 eV above the valence band edge. Selection of a particular defect pinning level depends strongly on the relative positions of the silicide work function and the defect energy level on an absolute energy scale.

  14. Locomotion of free-swimming ghost knifefish: anal fin kinematics during four behaviors.

    Science.gov (United States)

    Youngerman, Eric D; Flammang, Brooke E; Lauder, George V

    2014-10-01

    The maneuverability demonstrated by the weakly electric ghost knifefish (Apteronotus albifrons) is a result of its highly flexible ribbon-like anal fin, which extends nearly three-quarters the length of its body and is composed of approximately 150 individual fin rays. To understand how movement of the anal fin controls locomotion we examined kinematics of the whole fin, as well as selected individual fin rays, during four locomotor behaviors executed by free-swimming ghost knifefish: forward swimming, backward swimming, heave (vertical) motion, and hovering. We used high-speed video (1000 fps) to examine the motion of the entire anal fin and we measured the three-dimensional curvature of four adjacent fin rays in the middle of the fin during each behavior to determine how individual fin rays bend along their length during swimming. Canonical discriminant analysis separated all four behaviors on anal fin kinematic variables and showed that forward and backward swimming behaviors contrasted the most: forward behaviors exhibited a large anterior wavelength and posterior amplitude while during backward locomotion the anal fin exhibited both a large posterior wavelength and anterior amplitude. Heave and hover behaviors were defined by similar kinematic variables; however, for each variable, the mean values for heave motions were generally greater than for hovering. Individual fin rays in the middle of the anal fin curved substantially along their length during swimming, and the magnitude of this curvature was nearly twice the previously measured maximum curvature for ray-finned fish fin rays during locomotion. Fin rays were often curved into the direction of motion, indicating active control of fin ray curvature, and not just passive bending in response to fluid loading. Copyright © 2014 Elsevier GmbH. All rights reserved.

  15. Investigation of contact resistance for fin-tube heat exchanger by means of tube expansion

    Science.gov (United States)

    Hing, Yau Kar; Raghavan, Vijay R.; Meng, Chin Wai

    2012-06-01

    An experimental study on the heat transfer performance of a fin-tube heat exchanger due to mechanical expansion of the tube by bullets has been reported in this paper. The manufacture of a fin-tube heat exchanger commonly involves inserting copper tubes into a stack of aluminium fins and expanding the tubes mechanically. The mechanical expansion is achieved by inserting a steel bullet through the tube. The steel bullet has a larger diameter than the tube and the expansion provides a firm surface contact between fins and tubes. Five bullet expansion ratios (i.e. 1.045 to 1.059) have been used in the study to expand a 9.52mm diameter tubes in a fin-tube heat exchanger. The study is conducted on a water-to-water loop experiment rig under steady state conditions. In addition, the effects of fin hardness and fin pitch are investigated in the study. The results indicate that the optimum heat transfer occurred at a bullet expansion ratio ranging from 1.049 to 1.052. It is also observed that larger fin pitches require larger bullet expansion ratios, especially with lower fin hardness. As the fin pitch increases, both fin hardness (i.e. H22 and H24) exhibit increasing heat transfer rate per fin (W/fin). With the H22 hardness temper, the increase is as much as 11% while H24 increases by 1.2%.

  16. Transcriptional components of anteroposterior positional information during zebrafish fin regeneration.

    Science.gov (United States)

    Nachtrab, Gregory; Kikuchi, Kazu; Tornini, Valerie A; Poss, Kenneth D

    2013-09-01

    Many fish and salamander species regenerate amputated fins or limbs, restoring the size and shape of the original appendage. Regeneration requires that spared cells retain or recall information encoding pattern, a phenomenon termed positional memory. Few factors have been implicated in positional memory during vertebrate appendage regeneration. Here, we investigated potential regulators of anteroposterior (AP) pattern during fin regeneration in adult zebrafish. Sequence-based profiling from tissues along the AP axis of uninjured pectoral fins identified many genes with region-specific expression, several of which encoded transcription factors with known AP-specific expression or function in developing embryonic pectoral appendages. Transgenic reporter strains revealed that regulatory sequences of the transcription factor gene alx4a activated expression in fibroblasts and osteoblasts within anterior fin rays, whereas hand2 regulatory sequences activated expression in these same cell types within posterior rays. Transgenic overexpression of hand2 in all pectoral fin rays did not affect formation of the proliferative regeneration blastema, yet modified the lengths and widths of regenerating bones. Hand2 influenced the character of regenerated rays in part by elevation of the vitamin D-inactivating enzyme encoded by cyp24a1, contributing to region-specific regulation of bone metabolism. Systemic administration of vitamin D during regeneration partially rescued bone defects resulting from hand2 overexpression. Thus, bone-forming cells in a regenerating appendage maintain expression throughout life of transcription factor genes that can influence AP pattern, and differ across the AP axis in their expression signatures of these and other genes. These findings have implications for mechanisms of positional memory in vertebrate tissues.

  17. Creating Usable Pin Array Tactons for Non-Visual Information

    CERN Document Server

    Pietrzak, Thomas; Stephen, Brewster A; Martin, Benoît; Pecci, Isabelle; 10.1109/TOH.2009.6

    2012-01-01

    Spatial information can be difficult to present to a visually impaired computer user. In this paper we examine a new kind of tactile cueing for non-visual interaction as a potential solution, building on earlier work on vibrotactile Tactons. However, unlike vibrotactile Tactons, we use a pin array to stimulate the finger tip. Here, we describe how to design static and dynamic Tactons by defining their basic components. We then present user tests examining how easy it is to distinguish between different forms of pin array Tactons demonstrating accurate Tacton sets to represent directions. These experiments demonstrate usable patterns for static, wave and blinking pin array Tacton sets for guiding a user in one of eight directions. A study is then described that shows the benefits of structuring Tactons to convey information through multiple parameters of the signal. By using multiple independent parameters for a Tacton, this study demonstrates participants perceive more information through a single Tacton. Two...

  18. Pin Tool Geometry Effects in Friction Stir Welding

    Science.gov (United States)

    Querin, J. A.; Rubisoff, H. A.; Schneider, J. A.

    2009-01-01

    In friction stir welding (FSW) there is significant evidence that material can take one of two different flow paths when being displaced from its original position in front of the pin tool to its final position in the wake of the weld. The geometry of the pin tool, along with the process parameters, plays an important role in dictating the path that the material takes. Each flow path will impart a different thermomechanical history on the material, consequently altering the material microstructure and subsequent weld properties. The intention of this research is to isolate the effect that different pin tool attributes have on the flow paths imparted on the FSWed material. Based on published weld tool geometries, a variety of weld tools were fabricated and used to join AA2219. Results from the tensile properties and microstructural characterization will be presented.

  19. Transverse commensurability effect for vortices on periodic pinning arrays

    Energy Technology Data Exchange (ETDEWEB)

    Reichhardt, Charles [Los Alamos National Laboratory; Reichhardt, Cynthia J [Los Alamos National Laboratory

    2008-01-01

    Using computer simulations, we demonstrate a type of commensurability that occurs for vortices moving longitudinally through periodic pinning arrays in the presence of an additional transverse driving force. As a function of vortex density, there is a series of broad maxima in the transverse critical depinning force that do not fall at the matching fields where the number of vortices equals an integer multiple of the number of pinning sites. The commensurability effects are associated with dynamical states in which evenly spaced structures consisting of one or more moving rows of vortices form between rows of pinning sites. Remarkably, the critical transverse depinning force can be more than an order of magnitude larger than the longitudinal depinning force.

  20. Pinning force scaling of electrospun Bi-2212 nanowire networks

    Science.gov (United States)

    Koblischka, Michael R.; Gokhfeld, Denis; Chang, Crosby; Hauet, Thomas; Hartmann, Uwe

    2017-09-01

    Flux pinning forces were determined on different network samples of superconducting Bi2Sr2CaCu2O8 (Bi-2212) nanowires prepared by the electrospinning technique. We employed magnetization data determined by SQUID magnetometry in a wide temperature range 10 K signal prevails. The scaling analysis of the pinning forces was applied to interprete the data obtained. Both pure and Li-doped Bi2212 nanowire networks exhibit a peak position of h0 ∼ 0.11, which is smaller than the expected value of h0 = 0.2 indicating flux pinning at grain boundaries or extended defects. For the flowing currents through such a network, the crystallographic anisotropy and the percolation play an important role, resulting in reduced peak positions as compared to bulk samples.