Experimental comparison of the optical measurements of a cross-flow in a rod bundle with mixing vanes

International Nuclear Information System (INIS)

Chang, Seok Kyu; Choo, Yeon Jun; Kim, Bok Deuk; Song, Chul Hwa

2008-01-01

The lateral crossflow on subchannels in a rod bundle array was investigated to understand the flow characteristics related to the mixing vane types on a spacer grid by using the PIV technique. For more measurement resolutions, a 5x5 rod bundle was fabricated a 2.6 times larger than the real rod bundle size in a pressurized water reactor. A rod-embedded optic array was specially designed and used for the illumination of the inner subchannels. The crossflow field in a subchannel was characterized by the type and the arrangement of the mixing vanes. At a near downstream location from the spacer grid (z/D h =1) in the case of the split type, a couple of small vortices were generated diagonally in a subchannel. On the other hand, in the case of the swirl type, there was a large elliptic vortex generated in the center of a subchannel. The measurement results were compared with the experimental results which had been performed with the LDV technique at the same test facility. The magnitudes of the flow velocity and the vorticity in PIV results were less than those in LDV measurement results. It was shown that the instantaneous flow fields in a subchannel frequently have quite different shapes from the averaged one

Sliding vane geometry turbines

Science.gov (United States)

Sun, Harold Huimin; Zhang, Jizhong; Hu, Liangjun; Hanna, Dave R

2014-12-30

Various systems and methods are described for a variable geometry turbine. In one example, a turbine nozzle comprises a central axis and a nozzle vane. The nozzle vane includes a stationary vane and a sliding vane. The sliding vane is positioned to slide in a direction substantially tangent to an inner circumference of the turbine nozzle and in contact with the stationary vane.

CFD simulation and validation of turbulent mixing in a rod bundle with vaned spacer grids based on LDV test

International Nuclear Information System (INIS)

Chen Xi; Li Songwei; Li Zhongchun; Du Sijia; Zhang Yu; Peng Huanhuan

2017-01-01

Spacer grids with mixing vanes are generally used in fuel assemblies of Pressurized Water Reactor (PWR), because that mixing vanes could enhance the lateral turbulent mixing in subchannels. Thus, heat exchangements are more efficient, and the value of departure from nucleate boiling (DNB) is greatly increased. Actually turbulent mixing is composed of two kinds of flows: swirling flow inside the subchannel and cross flow between subchannels. Swirling flow could induce mixing between hot water near the rod and cold water in the center of the subchannel, and may accelerate deviation of the bubbles from the rod surface. Besides, crossing flow help to mixing water between hot subchannels and cold subchannels, which impact relatively large flow area. As a result, how to accurately capture and how to predict the complicated mixing phenomenon are of great concernments. Recently many experimental studies has been conducted to provide detailed turbulent mixing in rod bundle, among which Laser Doppler Velocimetry method is widely used. With great development of Computational Fluid Dynamics, CFD has been validated as an analysis method for nuclear engineering, especially for single phase calculation. This paper presents the CFD simulation and validation of the turbulent mixing induced by spacer grid with mixing vanes in rod bundles. Experiment data used for validation came from 5 x 5 rod bundle test with LDV technology, which is organized by Science and Technology on Reactor System Design Technology Laboratory. A 5 x 5 rod bundle with two spacer grids were used. Each rod has dimension of 9.5 mm in outer diameter and distance between rods is 12.6 mm. Two axial bulk velocities were conducted at 3.0 m/s for high Reynolds number and 1.0 m/s for low Reynolds number. Working pressure was 1.0 bar, and temperature was about 25degC. Two different distances from the downstream of the mixing spacer grid and one from upstream were acquired. Mean axial velocities and turbulent intensities

On the study of wavy leading-edge vanes to achieve low fan interaction noise

Science.gov (United States)

Tong, Fan; Qiao, Weiyang; Xu, Kunbo; Wang, Liangfeng; Chen, Weijie; Wang, Xunnian

2018-04-01

The application of wavy leading-edge vanes to reduce a single-stage axial fan noise is numerically studied. The aerodynamic and acoustic performance of the fan is numerically investigated using a hybrid unsteady Reynolds averaged Navier-Stokes (URANS)/acoustic analogy method (Goldstein equations). First, the hybrid URANS/Goldstein method is developed and successfully validated against experiment results. Next, numerical simulations are performed to investigate the noise reduction effects of the wavy leading-edge vanes. The aerodynamic and acoustic performance is assessed for a fan with vanes equipped with two different wavy leading-edge profiles and compared with the performance of conventional straight leading-edge vanes. Results indicate that a fan with wavy leading-edge vanes produces lower interaction noise than the baseline fan without a significant loss in aerodynamic performance. In fact, it is demonstrated that wavy leading-edge vanes have the potential to lead to both aerodynamic and acoustic improvements. The two different wavy leading-edge profiles are shown to successfully reduce the fan tone sound power level by 1.2 dB and 4.3 dB, respectively. Fan efficiency is also improved by about 1% with one of the tested wavy leading-edge profiles. Large eddy simulation (LES) is also performed for a simplified fan stage model to assess the effects of wavy leading-edge vanes on the broadband fan noise. Results indicate that the overall sound power level of a fan can be reduced by about 4 dB with the larger wavy leading-edge profile. Finally, the noise reduction mechanisms are investigated and analysed. It is found that the wavy leading-edge profiles can induce significant streamwise vorticity around the leading-edge protuberances and reduce pressure fluctuations (especially at locations of wavy leading-edge hills) and unsteady forces on the stator vanes. The underlying mechanism of the reduced pressure fluctuations is also discussed by examining the magnitude

Numerical prediction for effects of guide vane blade numbers on hydraulic turbine performance

International Nuclear Information System (INIS)

Shi, F X; Yang, J H; Wang, X H; Li, C E

2013-01-01

Using unstructured hybrid grid technique and SIMPLEC algorithm,a general three-dimensional simulation based on Reynolds Navier- stocks in multiple reference frames and the RNG k-ε turbulence model, is presented for the reversal centrifugal pump (PAT) with a guide vane. Four different schemes are designed by a change of the number of guide vane blade of PAT. The inner flow field in every scheme is simulated, accordingly, the external characteristic and static pressure distribution in flow field in PAT is obtained. The results obtained show that the efficiency can be improved by adding a guide vane for the PAT, besides, the high efficiency area is wider than before. Guide blade numbers changed, external characteristics of turbine changed, and the external characteristic changed. The optimal value is existent for the guide vane blade number, which has a great impact on the distribution of pressure in runner inlet

Heat pipe turbine vane cooling

Energy Technology Data Exchange (ETDEWEB)

Langston, L.; Faghri, A. [Univ. of Connecticut, Storrs, CT (United States)

1995-10-01

The applicability of using heat pipe principles to cool gas turbine vanes is addressed in this beginning program. This innovative concept involves fitting out the vane interior as a heat pipe and extending the vane into an adjacent heat sink, thus transferring the vane incident heat transfer through the heat pipe to heat sink. This design provides an extremely high heat transfer rate and an uniform temperature along the vane due to the internal change of phase of the heat pipe working fluid. Furthermore, this technology can also eliminate hot spots at the vane leading and trailing edges and increase the vane life by preventing thermal fatigue cracking. There is also the possibility of requiring no bleed air from the compressor, and therefore eliminating engine performance losses resulting from the diversion of compressor discharge air. Significant improvement in gas turbine performance can be achieved by using heat pipe technology in place of conventional air cooled vanes. A detailed numerical analysis of a heat pipe vane will be made and an experimental model will be designed in the first year of this new program.

Numerical Study of Bubble Coalescence and Breakup in the Reactor Fuel Channel with a Vaned Grid

Directory of Open Access Journals (Sweden)

Tenglong Cong

2018-01-01

Full Text Available The characteristics of bubbles of different sizes in fuel assembly are vital to two-phase flow resistance and heat transfer capacity. However, due to the swirl flow caused by the mixing vane, bubbles can crowd at the heated surface, which may anticipate the occurrence of departure from nucleation boiling. In the current work, the adiabatic two-phase flow in a simplified fuel assembly was analyzed by using the Eulerian two-fluid model and the MUSIG (MUltiple SIze Group model. This computational domain consists of two coolant channels and two sets of vaned spacers, with three sets of periodic boundary conditions at the side faces of the domain. The distributions of vapor phase and bubble diameters were obtained, based on which the effects of mixing vanes on the bubble characteristics were analyzed. Vapor phase crowded at the rod surface in the higher inlet vapor fraction case, but crowded in the channel center in the lower inlet vapor fraction cases. This work can be used as a reference for the design of mixing vanes to avoid the anticipation of departure of nucleation boiling that may be caused by unreasonable design.

Capacity control of rotary vane apparatus

International Nuclear Information System (INIS)

Roberts, R. W.

1985-01-01

A capacity control arrangement for a rotary vane fluid displacement apparatus, such as a rotary vane compressor, having a vane retaining means that normally engages and retains the vanes in their retracted or nonworking position within the rotor defined guide slits of such rotary vane compressor. The retaining means are actuated to the vane-disengaged position by hydraulic control fluid which is communicated to the retaining means in response to an external parameter sensed by a control means

RF field measurement of a four-vane type RFQ with PISLs

International Nuclear Information System (INIS)

Ueno, A.; Yamajaki, Y.

1992-01-01

Field instability due to a dipole mode mixing is the most significant disadvantage of an original four-vane type radio-frequency quadrupole (RFQ) linac. In order to avoid any dipole mode mixing, several pairs of vane coupling rings (VCRs) have mainly been used so far. However the VCR has complicated shape and is difficult to fabricate, particularly in the RFQ linac operated with a high-duty factor. Thus, a new field-stabilization concept was proposed and was referred to as a π-mode stabilizing loop (PISL) in a previous paper. The results of rf characteristics measurements on a low-power model cavity with or without PISLs are presented in this paper. The measurements showed that the PISLs were capable of stabilizing the accelerating mode, reducing the ratio of a dipole mode mixing from 7% to less than 1.5% (Author) 4 figs., tab., 10 refs

Optimization of submerged vane parameters

Indian Academy of Sciences (India)

H Sharma

the height or length of the submerged vane, no effective change in bed profile .... easily and again vanes will be ineffective, which is what. Odgaard and .... [3] Odgaard A J and Wang Y 1991a Sediment management with submerged vanes.

Gas turbine vane platform element

Science.gov (United States)

Campbell, Christian X [Oviedo, FL; Schiavo, Anthony L [Oviedo, FL; Morrison, Jay A [Oviedo, FL

2012-08-28

A gas turbine CMC shroud plate (48A) with a vane-receiving opening (79) that matches a cross-section profile of a turbine vane airfoil (22). The shroud plate (48A) has first and second curved circumferential sides (73A, 74A) that generally follow the curves of respective first and second curved sides (81, 82) of the vane-receiving opening. Walls (75A, 76A, 77A, 78A, 80, 88) extend perpendicularly from the shroud plate forming a cross-bracing structure for the shroud plate. A vane (22) may be attached to the shroud plate by pins (83) or by hoop-tension rings (106) that clamp tabs (103) of the shroud plate against bosses (105) of the vane. A circular array (20) of shroud plates (48A) may be assembled to form a vane shroud ring in which adjacent shroud plates are separated by compressible ceramic seals (93).

Lateral Flow Field Behavior Downstream of Mixing Vanes In a Simulated Nuclear Fuel Rod Bundle

International Nuclear Information System (INIS)

Conner, Michael E.; Smith, L. David III; Holloway, Mary V.; Beasley, Donald E.

2004-01-01

To assess the fuel assembly performance of PWR nuclear fuel assemblies, average subchannel flow values are used in design analyses. However, for this highly complex flow, it is known that local conditions around fuel rods vary dependent upon the location of the fuel rod in the fuel assembly and upon the support grid design that maintains the fuel rod pitch. To investigate the local flow in a simulated nuclear fuel rod bundle, a testing technique has been employed to measure the lateral flow field in a 5 x 5 rod bundle. Particle Image Velocimetry was used to measure the lateral flow field downstream of a support grid with mixing vanes for four unique subchannels in the 5 x 5 bundle. The dominant lateral flow structures for each subchannel are compared in this paper including the decay of these flow structures. (authors)

Rumsansning mellem vane og oplevelse

DEFF Research Database (Denmark)

Reeh, Henrik

2004-01-01

Walter Benjamin, Steen Eiler Rasmussen, arkitektur, sansning, vane, taktilitet, oplevelse, erfaring, Rom......Walter Benjamin, Steen Eiler Rasmussen, arkitektur, sansning, vane, taktilitet, oplevelse, erfaring, Rom...

Heavy quarkonium hybrids: Spectrum, decay, and mixing

Science.gov (United States)

Oncala, Ruben; Soto, Joan

2017-07-01

We present a largely model-independent analysis of the lighter heavy quarkonium hybrids based on the strong coupling regime of potential nonrelativistic QCD. We calculate the spectrum at leading order, including the mixing of static hybrid states. We use potentials that fulfill the required short and long distance theoretical constraints and fit well the available lattice data. We argue that the decay width to the lower lying heavy quarkonia can be reliably estimated in some cases and provide results for a selected set of decays. We also consider the mixing with heavy quarkonium states. We establish the form of the mixing potential at O (1 /mQ) , mQ being the mass of the heavy quarks, and work out its short and long distance constraints. The weak coupling regime of potential nonrelativistic QCD and the effective string theory of QCD are used for that goal. We show that the mixing effects may indeed be important and produce large spin symmetry violations. Most of the isospin zero XYZ states fit well in our spectrum, either as a hybrid or standard quarkonium candidate.

Hybrid Microwave Treatment of SRS TRU and Mixed Wastes

International Nuclear Information System (INIS)

Wicks, G.G.

1999-01-01

A new process, using hybrid microwave energy, has been developed as part of the Strategic Research and Development program and successfully applied to treatment of a wide variety of non-radioactive materials, representative of SRS transuranic (TRU) and mixed wastes. Over 35 simulated (non-radioactive) TRU and mixed waste materials were processed individually, as well as in mixed batches, using hybrid microwave energy, a new technology now being patented by Westinghouse Savannah River Company (WSRC)

A novel thermally driven rotor-vane/pressure-exchange ejector refrigeration system with environmental benefits and energy efficiency

International Nuclear Information System (INIS)

Hong, W.J.; Alhussan, Khaled; Zhang Hongfang; Garris, Charles A.

2004-01-01

The latest results of an ongoing coordinated experimental and computational program on the design and performance of a novel supersonic rotor-vane/pressure-exchange ejector for thermally driven ejector refrigeration systems are presented. For the supersonic rotor-vane/pressure-exchange ejector, careful management of the entropy rise through the oblique shocks and boundary layers is required for obtaining an advance in ejector performance. Since the invention of this new ejector is quite recent, understanding its aerodynamics, with the consequent optimization of performance, is in the formative stage. This paper shows how the supersonic aerodynamics is managed to provide the desirable flow induction characteristics through computational study and, in parallel, experimental results including flow visualization showing actual behavior with different-shaped rotor vanes. The importance of the existence of the tail part with a long expansion ramp, the sharp leading edge such as knife-edge, the proper height of leading edges, for the overall shape of rotor vane, were observed. Also the larger spin-angle rotor vane produces better flow induction and mixing between primary flow and secondary flow

A multigrid solution method for mixed hybrid finite elements

Energy Technology Data Exchange (ETDEWEB)

Schmid, W. [Universitaet Augsburg (Germany)

1996-12-31

We consider the multigrid solution of linear equations arising within the discretization of elliptic second order boundary value problems of the form by mixed hybrid finite elements. Using the equivalence of mixed hybrid finite elements and non-conforming nodal finite elements, we construct a multigrid scheme for the corresponding non-conforming finite elements, and, by this equivalence, for the mixed hybrid finite elements, following guidelines from Arbogast/Chen. For a rectangular triangulation of the computational domain, this non-conforming schemes are the so-called nodal finite elements. We explicitly construct prolongation and restriction operators for this type of non-conforming finite elements. We discuss the use of plain multigrid and the multilevel-preconditioned cg-method and compare their efficiency in numerical tests.

Vane clocking effects in an embedded compressor stage

Science.gov (United States)

Key, Nicole Leanne

The objective of this research was to experimentally investigate the effects of vane clocking, the circumferential indexing of adjacent vane rows with similar vane counts, in an embedded compressor stage. Experiments were performed in the Purdue 3-Stage Compressor, which consists of an IGV followed by three stages. The IGV, Stator 1, and Stator 2 have identical vane counts of 44, and the effects of clocking were studied on Stage 2. The clocking configuration that located the upstream vane wake on the Stator 2 leading edge was identified with total pressure measurements at the inlet to Stator 2 and confirmed with measurements at the exit of Stator 2. For both loading conditions, the total temperature results showed that there was no measurable change associated with vane clocking in the amount of work done on the flow. At design loading, the change in stage efficiency with vane clocking was 0.27 points between the maximum and minimum efficiency clocking configurations. The maximum efficiency configuration was the case where the Stator 1 wake impinged on the Stator 2 leading edge. This condition produced a shallower and thinner Stator 2 wake compared to the clocking configuration that located the wake in the middle of the Stator 2 passage. By locating the Stator 1 wake at the leading edge, it dampened the Stator 2 boundary layer response to inlet fluctuations associated with the Rotor 2 wakes. At high loading, the change in Stage 2 efficiency increased to 1.07 points; however, the maximum efficiency clocking configuration was the case where the Stator 1 wake passed through the middle of the downstream vane passage. At high loading, the flow physics associated with vane clocking were different than at design loading because the location of the Stator 1 wake fluid on the Stator 2 leading edge triggered a boundary layer separation on the suction side of Stator 2 producing a wider and deeper wake. Vane clocking essentially affects the amount of interaction between the

Design Concepts for Cooled Ceramic Matrix Composite Turbine Vanes

Science.gov (United States)

Boyle, Robert

2014-01-01

This project demonstrated that higher temperature capabilities of ceramic matrix composites (CMCs) can be used to reduce emissions and improve fuel consumption in gas turbine engines. The work involved closely coupling aerothermal and structural analyses for the first-stage vane of a high-pressure turbine (HPT). These vanes are actively cooled, typically using film cooling. Ceramic materials have structural and thermal properties different from conventional metals used for the first-stage HPT vane. This project identified vane configurations that satisfy CMC structural strength and life constraints while maintaining vane aerodynamic efficiency and reducing vane cooling to improve engine performance and reduce emissions. The project examined modifications to vane internal configurations to achieve the desired objectives. Thermal and pressure stresses are equally important, and both were analyzed using an ANSYS® structural analysis. Three-dimensional fluid and heat transfer analyses were used to determine vane aerodynamic performance and heat load distributions.

Intermediate flow mixing nonsupport grid for BWR fuel assembly

International Nuclear Information System (INIS)

Taleyarkhan, R.P.

1987-01-01

An intermediate flow mixing nonsupport grid is described for use in a nuclear reactor fuel assembly containing an array of elongated fuel rods. The grid comprises: (a) interleaved inner straps arranged in an egg-crate configuration to define inner cell openings for receiving respective ones of the fuel rods. The inner straps have outer terminal end portions; (b) an outer peripheral strap attached to the respective terminal end portions of the inner straps to define perimeter cell openings for receiving other ones of the fuel rods. The inner straps and outer strap together have opposite upstream and downstream sides; (c) a first group of mixing vanes disposed at the downstream side and being attached on portions of the outer strap and on respective portions of the inner straps. Together with the outer strap portions, they define the perimeter cell openings. Each of the mixing vanes of the first group extend generally in a downstream direction and inwardly toward the perimeter cell openings for deflecting coolant flowing; and (d) a second group of mixing vanes disposed at the downstream side and being attached on other portions of the inner straps. Together with the respective portions, they define the inner cell openings. Each of the mixing vanes of the second group extend generally in a downstream direction and inwardly toward the inner cell openings for deflecting coolant flowing therethrough; (e) the mixing vanes of the second group are substantially smaller in size than the mixing vanes of the first group so as to generate substantially less turbulence in the portions of the coolant flowing through the inner cell openings than in the portions of the coolant flowing through the perimeter cell openings

Vane coupling rings: a simple technique for stabilizing a four-vane radiofrequency quadrupole structure

International Nuclear Information System (INIS)

Howard, D.; Lancaster, H.

1982-11-01

The benefits of stabilized accelerating structures, with regard to the manufacture and operation, have been well documented. The four-vane radiofrequency quadrupoles (RFQ) presently being designed and constructed in many laboratories are not stabilized because of the weak electromagnetic coupling between the quadrant resonators. This paper presents a simple technique developed at the Lawrence Berkeley Laboratory using vane coupling rings (VCR's) which azimuthally stabilize the RFQ structure and greatly enhance its use as a practical accelerator. In particular, the VCR's: completely eliminate the dipole modes in the frequency range of interest; provide adequate quadrant balance with an initial precision mechanical alignment of the vanes; and enhance axial balance and simplify end tuners. Experimental verification tests on a scale model are discussed

Vane coupling rings: a simple technique for stabilizing a four-vane radiofrequency quadrupole structure

International Nuclear Information System (INIS)

Howard, D.; Lancaster, H.

1983-01-01

The benefits of stabilized accelerating structures, with regard to the manufacture and operation, have been well documented. The four-vane radiofrequency quadrupoles (RFQ) presently being designed and constructed in many laboratories are not stabilized because of the weak electromagnetic coupling between the quadrant resonators. This paper presents a simple technique developed at the Lawrence Berkeley Laboratory using vane coupling rings (VCR's) which azimuthally stabilize the RFQ structure and greatly enhance its use as a practical accelerator. In particular, the VCR's: Completely eliminate the dipole modes in the frequency range of interest; Provide adequate quadrant balance with an initial precision mechanical alignment of the vanes; Enhance axial balance and simplify end tuners. Experimental verification tests on a scale model will be discussed

Development and numerical analysis of low specific speed mixed-flow pump

International Nuclear Information System (INIS)

Li, H F; Huo, Y W; Pan, Z B; Zhou, W C; He, M H

2012-01-01

With the development of the city, the market of the mixed flow pump with large flux and high head is prospect. The KSB Shanghai Pump Co., LTD decided to develop low speed specific speed mixed flow pump to meet the market requirements. Based on the centrifugal pump and axial flow pump model, aiming at the characteristics of large flux and high head, a new type of guide vane mixed flow pump was designed. The computational fluid dynamics method was adopted to analyze the internal flow of the new type model and predict its performances. The time-averaged Navier-Stokes equations were closed by SST k-ω turbulent model to adapt internal flow of guide vane with larger curvatures. The multi-reference frame(MRF) method was used to deal with the coupling of rotating impeller and static guide vane, and the SIMPLEC method was adopted to achieve the coupling solution of velocity and pressure. The computational results shows that there is great flow impact on the head of vanes at different working conditions, and there is great flow separation at the tailing of the guide vanes at different working conditions, and all will affect the performance of pump. Based on the computational results, optimizations were carried out to decrease the impact on the head of vanes and flow separation at the tailing of the guide vanes. The optimized model was simulated and its performance was predicted. The computational results show that the impact on the head of vanes and the separation at the tailing of the guide vanes disappeared. The high efficiency of the optimized pump is wide, and it fit the original design destination. The newly designed mixed flow pump is now in modeling and its experimental performance will be getting soon.

Development and numerical analysis of low specific speed mixed-flow pump

Science.gov (United States)

Li, H. F.; Huo, Y. W.; Pan, Z. B.; Zhou, W. C.; He, M. H.

2012-11-01

With the development of the city, the market of the mixed flow pump with large flux and high head is prospect. The KSB Shanghai Pump Co., LTD decided to develop low speed specific speed mixed flow pump to meet the market requirements. Based on the centrifugal pump and axial flow pump model, aiming at the characteristics of large flux and high head, a new type of guide vane mixed flow pump was designed. The computational fluid dynamics method was adopted to analyze the internal flow of the new type model and predict its performances. The time-averaged Navier-Stokes equations were closed by SST k-ω turbulent model to adapt internal flow of guide vane with larger curvatures. The multi-reference frame(MRF) method was used to deal with the coupling of rotating impeller and static guide vane, and the SIMPLEC method was adopted to achieve the coupling solution of velocity and pressure. The computational results shows that there is great flow impact on the head of vanes at different working conditions, and there is great flow separation at the tailing of the guide vanes at different working conditions, and all will affect the performance of pump. Based on the computational results, optimizations were carried out to decrease the impact on the head of vanes and flow separation at the tailing of the guide vanes. The optimized model was simulated and its performance was predicted. The computational results show that the impact on the head of vanes and the separation at the tailing of the guide vanes disappeared. The high efficiency of the optimized pump is wide, and it fit the original design destination. The newly designed mixed flow pump is now in modeling and its experimental performance will be getting soon.

Design Concepts for Cooled Ceramic Composite Turbine Vane

Science.gov (United States)

Boyle, Robert J.; Parikh, Ankur H.; Nagpal, VInod K.

2015-01-01

The objective of this work was to develop design concepts for a cooled ceramic vane to be used in the first stage of the High Pressure Turbine(HPT). To insure that the design concepts were relevant to the gas turbine industry needs, Honeywell International Inc. was subcontracted to provide technical guidance for this work. The work performed under this contract can be divided into three broad categories. The first was an analysis of the cycle benefits arising from the higher temperature capability of Ceramic Matrix Composite(CMC) compared with conventional metallic vane materials. The second category was a series of structural analyses for variations in the internal configuration of first stage vane for the High Pressure Turbine(HPT) of a CF6 class commercial airline engine. The third category was analysis for a radial cooled turbine vanes for use in turboshaft engine applications. The size, shape and internal configuration of the turboshaft engine vanes were selected to investigate a cooling concept appropriate to small CMC vanes.

Velocity and pressure measurements in guide vane clearance gap of a low specific speed Francis turbine

Science.gov (United States)

Thapa, B. S.; Dahlhaug, O. G.; Thapa, B.

2016-11-01

In Francis turbine, a small clearance gap between the guide vanes and the cover plates is usually required to pivot guide vanes as a part of governing system. Deflection of cover plates and erosion of mating surfaces causes this gap to increase from its design value. The clearance gap induces the secondary flow in the distributor system. This effects the main flow at the runner inlet, which causes losses in efficiency and instability. A guide vane cascade of a low specific speed Francis turbine has been developed for experimental investigations. The test setup is able to produce similar velocity distributions at the runner inlet as that of a reference prototype turbine. The setup is designed for particle image velocimetry (PIV) measurements from the position of stay vane outlet to the position of runner inlet. In this study, velocity and pressure measurements are conducted with 2 mm clearance gap on one side of guide vane. Leakage flow is observed and measured together with pressure measurements. It is concluded that the leakage flow behaves as a jet and mixes with the main flow in cross-wise direction and forms a vortex filament. This causes non-uniform inlet flow conditions at runner blades.

Spacecraft Hybrid (Mixed-Actuator) Attitude Control Experiences on NASA Science Missions

Science.gov (United States)

Dennehy, Cornelius J.

2014-01-01

There is a heightened interest within NASA for the design, development, and flight implementation of mixed-actuator hybrid attitude control systems for science spacecraft that have less than three functional reaction wheel actuators. This interest is driven by a number of recent reaction wheel failures on aging, but what could be still scientifically productive, NASA spacecraft if a successful hybrid attitude control mode can be implemented. Over the years, hybrid (mixed-actuator) control has been employed for contingency attitude control purposes on several NASA science mission spacecraft. This paper provides a historical perspective of NASA's previous engineering work on spacecraft mixed-actuator hybrid control approaches. An update of the current situation will also be provided emphasizing why NASA is now so interested in hybrid control. The results of the NASA Spacecraft Hybrid Attitude Control Workshop, held in April of 2013, will be highlighted. In particular, the lessons learned captured from that workshop will be shared in this paper. An update on the most recent experiences with hybrid control on the Kepler spacecraft will also be provided. This paper will close with some future considerations for hybrid spacecraft control.

A Straight-bladed Vertical Axis Wind Turbine with a Directed Guide Vane Row-Effect of Guide Vane Geometry on the Performance-

Institute of Scientific and Technical Information of China (English)

Manabu TAKAO; Hideki KUMA; Takao MAEDA; Yasunari KAMADA; Michiaki OKI; Atsushi MINODA

2009-01-01

The objective of this study is to show the effect of guide vane geometry on the performance. In order to over-come the disadvantages of vertical axis wind turbine, a straight-bladed vertical axis wind turbine (S-VAWT) with a directed guide vane row has been proposed and tested by the authors. According to previous studies, it was clarified that the performance of the turbine can be improved by means of the directed guide vane row. However, the guide vane geometry of S-VAWT has not been optimized so far. In order to clarify the effect of guide vane geometry, the effects of setting angle and gap between rotor blade and guide vane on power coefficient and start-ing characteristic were investigated in the experiments. The experimental study of the proposed wind turbine was carded out by a wind tunnel. The wind tunnel with a diameter of 1.8m is open jet type. The wind velocity is 8 m/s in the experiments. The rotor has three straight blades with a profile of NACA0018 and a chord length of 100 mm, a diameter of 0.6 m and a blade height of 0.7 m. The guide vane row consists of 3 arc plates.

Effects of grid spacer with mixing vane on entrainments and depositions in two-phase annular flows

Directory of Open Access Journals (Sweden)

Akimaro Kawahara

2015-06-01

Full Text Available The effects of mixing vanes (MVs attached to a grid spacer on the characteristics of air–water annular flows were experimentally investigated. To know the effects, a grid spacer with or without MV was inserted in a vertical circular pipe of 16-mm internal diameter. For three cases (i.e., no spacer, spacer without MV, and spacer with MV, the liquid film thickness, liquid entrainment fraction, and deposition rate were measured by the constant current method, single liquid film extraction method, and double liquid film extraction method, respectively. The MVs significantly promote the re-deposition of liquid droplets in the gas core flow into the liquid film on the channel walls. The deposition mass transfer coefficient is three times higher for the spacer with MV than for the spacer without MV, even for cases 0.3-m downstream from the spacer. The liquid film thickness becomes thicker upstream and downstream for the spacer with MV, compared with the thickness for the spacer without MV and for the case with no spacer.

Design Considerations for Ceramic Matrix Composite Vanes for High Pressure Turbine Applications

Science.gov (United States)

Boyle, Robert J.; Parikh, Ankur H.; Nagpal, Vinod K.; Halbig, Michael C.

2013-01-01

Issues associated with replacing conventional metallic vanes with Ceramic Matrix Composite (CMC) vanes in the first stage of the High Pressure Turbine (HPT) are explored. CMC materials have higher temperature capability than conventional HPT vanes, and less vane cooling is required. The benefits of less vane coolant are less NOx production and improved vane efficiency. Comparisons between CMC and metal vanes are made at current rotor inlet temperatures and at an vane inlet pressure of 50 atm.. CMC materials have directionally dependent strength characteristics, and vane designs must accommodate these characteristics. The benefits of reduced NOx and improved cycle efficiency obtainable from using CMC vanes. are quantified Results are given for vane shapes made of a two dimensional CMC weave. Stress components due to thermal and pressure loads are shown for all configurations. The effects on stresses of: (1) a rib connecting vane pressure and suction surfaces; (2) variation in wall thickness; and (3) trailing edge region cooling options are discussed. The approach used to obtain vane temperature distributions is discussed. Film cooling and trailing edge ejection were required to avoid excessive vane material temperature gradients. Stresses due to temperature gradients are sometimes compressive in regions where pressure loads result in high tensile stresses.

QCD sum-rules analysis of vector (1-) heavy quarkonium meson-hybrid mixing

Science.gov (United States)

Palameta, A.; Ho, J.; Harnett, D.; Steele, T. G.

2018-02-01

We use QCD Laplace sum rules to study meson-hybrid mixing in vector (1-) heavy quarkonium. We compute the QCD cross-correlator between a heavy meson current and a heavy hybrid current within the operator product expansion. In addition to leading-order perturbation theory, we include four- and six-dimensional gluon condensate contributions as well as a six-dimensional quark condensate contribution. We construct several single and multiresonance models that take known hadron masses as inputs. We investigate which resonances couple to both currents and so exhibit meson-hybrid mixing. Compared to single resonance models that include only the ground state, we find that models that also include excited states lead to significantly improved agreement between QCD and experiment. In the charmonium sector, we find that meson-hybrid mixing is consistent with a two-resonance model consisting of the J /ψ and a 4.3 GeV resonance. In the bottomonium sector, we find evidence for meson-hybrid mixing in the ϒ (1 S ) , ϒ (2 S ), ϒ (3 S ), and ϒ (4 S ).

A horizontal vane radiometer: Experiment, theory, and simulation

Energy Technology Data Exchange (ETDEWEB)

Wolfe, David; Larraza, Andres, E-mail: larraza@nps.edu [Department of Physics, Naval Postgraduate School, Monterey, California 93940 (United States); Garcia, Alejandro [Department of Physics and Astronomy, San Jose State University, San Jose, California 95152 (United States)

2016-03-15

The existence of two motive forces on a Crookes radiometer has complicated the investigation of either force independently. The thermal creep shear force in particular has been subject to differing interpretations of the direction in which it acts and its order of magnitude. In this article, we provide a horizontal vane radiometer design which isolates the thermal creep shear force. The horizontal vane radiometer is explored through experiment, kinetic theory, and the Direct Simulation Monte Carlo (DSMC) method. The qualitative agreement between the three methods of investigation is good except for a dependence of the force on the width of the vane even when the temperature gradient is narrower than the vane which is present in the DSMC method results but not in the theory. The experimental results qualitatively resemble the theory in this regard. The quantitative agreement between the three methods of investigation is better than an order of magnitude in the cases examined. The theory is closer to the experimental values for narrow vanes and the simulations are closer to the experimental values for the wide vanes. We find that the thermal creep force acts from the hot side to the cold side of the vane. We also find the peak in the radiometer’s angular speed as a function of pressure is explained as much by the behavior of the drag force as by the behavior of the thermal creep force.

A horizontal vane radiometer: Experiment, theory, and simulation

International Nuclear Information System (INIS)

Wolfe, David; Larraza, Andres; Garcia, Alejandro

2016-01-01

The existence of two motive forces on a Crookes radiometer has complicated the investigation of either force independently. The thermal creep shear force in particular has been subject to differing interpretations of the direction in which it acts and its order of magnitude. In this article, we provide a horizontal vane radiometer design which isolates the thermal creep shear force. The horizontal vane radiometer is explored through experiment, kinetic theory, and the Direct Simulation Monte Carlo (DSMC) method. The qualitative agreement between the three methods of investigation is good except for a dependence of the force on the width of the vane even when the temperature gradient is narrower than the vane which is present in the DSMC method results but not in the theory. The experimental results qualitatively resemble the theory in this regard. The quantitative agreement between the three methods of investigation is better than an order of magnitude in the cases examined. The theory is closer to the experimental values for narrow vanes and the simulations are closer to the experimental values for the wide vanes. We find that the thermal creep force acts from the hot side to the cold side of the vane. We also find the peak in the radiometer’s angular speed as a function of pressure is explained as much by the behavior of the drag force as by the behavior of the thermal creep force.

Looking for a gift of Nature: Hadron loops and hybrid mixing

International Nuclear Information System (INIS)

Close, Frank; Thomas, Christopher

2009-01-01

We investigate how coupling of valence q qbar to meson pairs can modify the properties of conventional q qbar and hybrid mesons. In a symmetry limit the mixing between hybrids and conventional q qbar with the same J PC is shown to vanish. Flavor mixing between heavy and light q qbar due to meson loops is shown to be dual to the

The influence of the vane on the lubrication characteristics between the vane and the rolling piston of a rotary compressor

International Nuclear Information System (INIS)

Cho, Ihn Sung; Jung, Jae Youn

2006-01-01

The rolling piston type rotary compressor has been widely used for refrigeration and air -conditioning systems due to its compactness and high-speed operation. The present analysis is part of a research program directed toward maximizing the advantages of refrigerant compressors. The study of lubrication characteristics in the critical sliding component is essential for the design of refrigerant compressors. Therefore, theoretical investigation of the lubrication characteristics of a rotary compressor being used for refrigeration and air-conditioning systems was investigated. The Newton-Raphson method was used for a partial elastohydrodynamic lubrication analysis between the vane and the rolling piston of a rotary compressor. The results demonstrated that the vane thickness and the center line position of the vane significantly influenced the friction force and the energy loss between the vane and the rolling piston

Hopping mixed hybrid excitations in multiple composite quantum wire structures

International Nuclear Information System (INIS)

Nguyen Ba An; Tran Thai Hoa

1995-10-01

A structure consisting of N pairs of inorganic semiconductor and organic quantum wires is considered theoretically. In such an isolated pair of wires, while the intrawire coupling forms Wannier-Mott exciton in an inorganic semiconductor quantum wire and Frenkel exciton in an organic one, the interwire coupling gives rise to hybrid excitons residing within the pair. When N pairs of wires are packed together 2N new mixed hybrid modes appear that are the true elementary excitations and can hop throughout the whole structure. Energies and wave functions of such hopping mixed hybrid excitations are derived analytically in detail accounting for the global interwire coupling and the different polarization configurations. (author). 19 refs

Numerical Analysis and Geometry Optimisation of Vertical Vane of Room Air-conditioner

Directory of Open Access Journals (Sweden)

Al-Obaidi Abdulkareem Sh. Mahdi

2018-01-01

Full Text Available Vertical vanes of room air-conditioners are used to control and direct cold air. This paper aims to study vertical vane as one of the parameters that affect the efficiency of dissipating cold air to a given space. The vertical vane geometry is analysed and optimised for lower production cost using CFD. The optimised geometry of the vertical vane should have the same or increased efficiency of dissipating cold air and have lesser mass compared to the existing original design. The existing original design of vertical vane is simplified and analysed by using ANSYS Fluent. Efficiency of wind direction is define as how accurate the direction of airflow coming out from vertical vane. In order to calculate the efficiency of wind direction, 15° and 30° rotation of vertical vane inside room air-conditioner are simulated. The efficiency of wind direction for 15° rotation of vertical vane is 57.81% while efficiency of wind direction for 30° rotation of vertical vane is 47.54%. The results of the efficiency of wind direction are used as base reference for parametric study. The parameters investigated for optimisation of vertical vane are focused at length of long span, tip chord and short span. The design of 15% decreased in vane surface area at tip chord is the best optimised design of vertical vane because the efficiency of wind direction is the highest as 60.32%.

Preliminary results for validation of Computational Fluid Dynamics for prediction of flow through a split vane spacer grid

International Nuclear Information System (INIS)

Rashkovan, A.; Novog, D.R.

2012-01-01

This paper presents the results of the CFD simulations of turbulent flow past spacer grid with mixing vanes. This study summarizes the first stage of the ongoing numerical blind exercise organized by OECD-NEA. McMaster University along with other participants plan to submit a numerical prediction of the detailed flow field and turbulence characteristics of the flow past 5x5 rod bundle with a spacer grid equipped with two types of mixing vanes. The results will be compared with blind experimental measurements performed in Korea. Due to the fact that a number of the modeling strategies are suggested in literature for such types of flows, we have performed a series of tests to assess the mesh requirements, flow steadiness, turbulence modeling and wall treatment effects. Results of these studies are reported in the present paper. (author)

Solar energy system with wind vane

Science.gov (United States)

Grip, Robert E

2015-11-03

A solar energy system including a pedestal defining a longitudinal axis, a frame that is supported by the pedestal and that is rotateable relative to the pedestal about the longitudinal axis, the frame including at least one solar device, and a wind vane operatively connected to the frame to urge the frame relative to the pedestal about the longitudinal axis in response to wind acting on the wind vane.

Numerical study on dissimilar guide vane design with SCC piston for air and emulsified biofuel mixing improvement

Directory of Open Access Journals (Sweden)

Hamid Mohd Fadzli

2017-01-01

Full Text Available Crude palm oil (CPO is one of the most potential biofuels that can be applied in the conventional diesel engines, where the chemical properties of CPO are comparable to diesel fuel. However, its higher viscosity and heavier molecules can contributes to several engine problems such as low atomization during injection, carbon deposit formation, injector clogging, low mixing with air and lower combustion efficiency. An emulsification of biofuel and modifications of few engine critical components have been identified to mitigate the issues. This paper presents the effects of dissimilar guide vane design (GVD in terms of height variation of 0.25R, 0.3R and 0.35R at the intake manifold with shallow depth re-entrance combustion chamber (SCC piston application to the incylinder air flow characteristics improvement. The simulation results show that the intake manifold with GVD improved the performance of the air flow characteristic particularly swirl, tumble and cross tumble ratios from the intake manifold to the engine. The GVD with the height of 0.3R was found to be the optimum design with respect to the overall improvement of the air flow characteristic. The improvement of the air flow characteristic with the application of GVD and SCC piston in the engine was expected to contribute to a better air fuel mixing, fuel atomization and combustion efficiency of the engine using emulsified biofuel as a source of fuel.

Study of the laboratory Vane test on mortars

Energy Technology Data Exchange (ETDEWEB)

Bauer, Elton [Post-Graduate Program in Structures and Civil Construction, Civil and Environmental Engineering Department, University of Brasilia Campus Universitario Darcy Ribeiro Asa Norte, 70910-900 Brasilia/DF (Brazil); Sousa, Jose G.G. de [Federal University of Vale do Sao Francisco, Av. Presidente Tancredo Neve, 100-56306-410 Petroline/PE (Brazil); Guimaraes, Elvio A. [University of Feira de Santana, Campus Universitario-BR 116, Km 03-44031-460-Feira de Santana/BA (Brazil); Silva, Francisco Gabriel S. [Post-Graduate Program in Structures and Civil Construction, University of Brasilia Campus Universitario Darcy Ribeiro Asa Norte, 70910-900 Brasilia/DF (Brazil)

2007-01-15

The Vane method (Vane test) is a simple but efficient method to measure the yield stress among other properties of non-Newtonian fluids. These fluids exhibit big flow effects in flat surfaces which are common in rheometers devices of different types (parallel disk or coaxial cylinder types). The yield stress values obtained with Vane method, in pastes, gels, soils and concentrated suspensions, have presented good agreement with results found elsewhere by most of the rheologic methods shown in the literature. The aim of this work is presenting a discussion on the capabilities of the Vane method, highlighting the theoretical basis, the functioning principle with some operational particularities, and some applications of the method in investigating the properties of fresh rendering mortars. Works of several authors that used the same method for fresh mortars were reviewed and experimental results of tests done by the authors of this paper using the method are also presented and discussed, focusing on the desirable workability for mortars. The Vane test method is an important tool in studying rheological properties in freshly applied mortar. It is able to define clear conditions in the applying of this material. (author)

Optimization analysis of a new vane MRF damper

Energy Technology Data Exchange (ETDEWEB)

Zhang, J Q; Feng, Z Z; Jing, Q [Department of Technical Support Engineering, Academy of Armored Force Engineering, Beijing, 100072 (China)], E-mail: zhangjq63@yahoo.com.cn

2009-02-01

The primary purpose of this study was to provide the optimization analysis certain characteristics and benefits of a vane MRF damper. Based on the structure of conventional vane hydraulic damper for heavy vehicle, a narrow arc gap between clapboard and rotary vane axle, which one rotates relative to the other, was designed for MRF valve and the mathematical model of damping was deduced. Subsequently, the finite element analysis of electromagnetic circuit was done by ANSYS to perform the optimization process. Some ways were presented to augment the damping adjustable multiple under the condition of keeping initial damping forces and to increase fluid dwell time through the magnetic field. The results show that the method is useful in the design of MR dampers and the damping adjustable range of vane MRF damper can meet the requirement of heavy vehicle semi-active suspension system.

Turbocharger with variable nozzle having vane sealing surfaces

Science.gov (United States)

Arnold, Philippe [Hennecourt, FR; Petitjean, Dominique [Julienrupt, FR; Ruquart, Anthony [Thaon les Vosges, FR; Dupont, Guillaume [Thaon les Vosges, FR; Jeckel, Denis [Thaon les Vosges, FR

2011-11-15

A variable nozzle for a turbocharger includes a plurality of vanes rotatably mounted on a nozzle ring and disposed in a nozzle flow path defined between the nozzle ring and an opposite nozzle wall. Either or both of the faces of the nozzle ring and nozzle wall include(s) at least one step that defines sealing surfaces positioned to be substantially abutted by airfoil surfaces of the vanes in the closed position of the vanes and to be spaced from the airfoil surfaces in positions other than the closed position. This substantial abutment between the airfoil surfaces and the sealing surfaces serves to substantially prevent exhaust gas from leaking past the ends of the airfoil portions. At the same time, clearances between the nozzle ring face and the end faces of the airfoil portions can be sufficiently large to prevent binding of the vanes under all operating conditions.

Evaluation of vertical coordinate and vertical mixing algorithms in the HYbrid-Coordinate Ocean Model (HYCOM)

Science.gov (United States)

Halliwell, George R.

Vertical coordinate and vertical mixing algorithms included in the HYbrid Coordinate Ocean Model (HYCOM) are evaluated in low-resolution climatological simulations of the Atlantic Ocean. The hybrid vertical coordinates are isopycnic in the deep ocean interior, but smoothly transition to level (pressure) coordinates near the ocean surface, to sigma coordinates in shallow water regions, and back again to level coordinates in very shallow water. By comparing simulations to climatology, the best model performance is realized using hybrid coordinates in conjunction with one of the three available differential vertical mixing models: the nonlocal K-Profile Parameterization, the NASA GISS level 2 turbulence closure, and the Mellor-Yamada level 2.5 turbulence closure. Good performance is also achieved using the quasi-slab Price-Weller-Pinkel dynamical instability model. Differences among these simulations are too small relative to other errors and biases to identify the "best" vertical mixing model for low-resolution climate simulations. Model performance deteriorates slightly when the Kraus-Turner slab mixed layer model is used with hybrid coordinates. This deterioration is smallest when solar radiation penetrates beneath the mixed layer and when shear instability mixing is included. A simulation performed using isopycnic coordinates to emulate the Miami Isopycnic Coordinate Ocean Model (MICOM), which uses Kraus-Turner mixing without penetrating shortwave radiation and shear instability mixing, demonstrates that the advantages of switching from isopycnic to hybrid coordinates and including more sophisticated turbulence closures outweigh the negative numerical effects of maintaining hybrid vertical coordinates.

Demonstration and Field Evaluation of Streambank Stabilization with Submerged Vanes

Science.gov (United States)

Whitman, H.; Hoopes, J.; Poggi, D.; Fitzpatrick, F.; Walz, K.; ,

2001-01-01

The effectiveness of submerged vanes for reducing bank erosion and improving aquatic habitat is being evaluated at a site on North Fish Creek, a Lake Superior tributary. Increased runoff from agricultural areas with clayey soils has increased flood magnitudes and the erosion potential/transport capacity of the stream. Most of the creek's sediment load originates from the erosion of 17 large bluffs. This creek contains important recreational fisheries that are potentially limited by the loss of aquatic habitat from deposition of sediment on spawning beds. Submerged vanes are a cost effective and environmentally less intrusive alternative to traditional structural stabilization measures. Submerged vanes protrude from a channel bed, are oriented at an angle to the local velocity, and are distributed along a portion of channel. They induce a transverse force and torque on the flow along with longitudinal vortexes that alter the cross sectional shape and alignment of the channel. Submerged vanes were installed at a bluff/bend site in summer and fall 2000. The number, size, and layout of the vanes were based upon the channel morphology under estimated bankfull conditions. The effectiveness of the vanes will be evaluated by comparing surveys of the bluff face, streamflow, and channel conditions for several years after installation of the submerged vanes with surveys before and immediately after their installation.

Suppression of tonal noise in a centrifugal fan using guide vanes

Science.gov (United States)

Paramasivam, Kishokanna; Rajoo, Srithar; Romagnoli, Alessandro

2015-11-01

This paper presents the work aiming for tonal noise reduction in a centrifugal fan. In previous studies, it is well documented that tonal noise is the dominant noise source generated in centrifugal fans. Tonal noise is generated due to the aerodynamic interaction between the rotating impeller and stationary diffuser vanes. The generation of tonal noise is related to the pressure fluctuation at the leading edge of the stationary vane. The tonal noise is periodic in time which occurs at the blade passing frequency (BPF) and its harmonics. Much of previous studies, have shown that the stationary vane causes the tonal noise and generation of non-rotational turbulent noise. However, omitting stationary vanes will lead to the increase of non-rotational turbulent noise resulted from the high velocity of the flow leaving the impeller. Hence in order to reduce the tonal noise and the non-rotational noise, guide vanes were designed as part of this study to replace the diffuser vanes, which were originally used in the chosen centrifugal fan. The leading edge of the guide vane is tapered. This modification reduces the strength of pressure fluctuation resulting from the interaction between the impeller outflow and stationary vane. The sound pressure level at blade passing frequency (BPF) is reduced by 6.8 dB, the 2nd BPF is reduced by 4.1 dB and the 3rd BPF reduced by about 17.5 dB. The overall reduction was 0.9 dB. The centrifugal fan with tapered guide vanes radiates lower tonal noise compared to the existing diffuser vanes. These reductions are achieved without compromising the performance of the centrifugal fan. The behavior of the fluid flow was studied using computational fluid dynamics (CFD) tools and the acoustics characteristics were determined through experiments in an anechoic chamber.

Introduction on KPS's maintenance experience of the swirl vane assemblies of primary separators for SG model F in Korea

International Nuclear Information System (INIS)

Kim, Yong tae

2003-01-01

Recently, we had experienced to replace the Swirl Vane Assemblies of primary moisture separator for SG model F in Korea because of serious degradation (Thinning) in carbon steel swirl vane blades and carbon steel separator barrel wall adjacent to swirl vane blades. When the symptom was observed by us at the first time on the swirl vane assemblies, there were small or a bit clear erosion / or corrosion marks on the edge regions of the blades but within 3 cycles of operation, we found that those marks became holes which penetrated the most of swirl vane assemblies and even more seriously, some parts of the assemblies were worn-out. Therefore, we concluded that the speed of degradation would be very rapid and serious from the beginning stage. It had been assumed that these kinds of thinning problems would be due to FAC(Flow Accelerated Corrosion) because the plants having these problems are using a highly concentrated hydrazine for the water treatment of secondary side which lead to reduce the oxygen and pH in the water. What are more serious reasons will be that the swirl vane assemblies are very weak to FAC because they were made by a low concentrated chromium carbon steel and the assemblies would have to be under the operation conditions of the highly turbulent steam-water mixed fluid with the operating temperature of higher than 280 .deg. C. Potentially, the damaged swirl vane assemblies of the primary moisture separator may create bad influences for the plant operation because it may cause the rupture of SG Tubes and over-exceed fluid influx onto the turbine and etc. KPS had successfully performed the replacement of the degraded swirl vane assemblies through our own planning and preparation. This was the unique case in all over the world and I would like to introduce you about our unique repair experience to prepare an expected future situation as we see the similar problems in other model F SGs operating in Korea

Study on Orbital Liquid Transport and Interface Behavior in Vane Tank

Science.gov (United States)

Kang, Qi; Rui, Wei

2016-07-01

Liquid propellant tank is used to supply gas free liquid for spacecraft as an important part of propulsion system. The liquid behavior dominated by surface tension in microgravity is obviously different with that on the ground, which put forward a new challenge to the liquid transport and relocation. The experiments which are investigated at drop tower in National Microgravity Lab have concentrated on liquid relocation following thruster firing. Considered that the liquid located at the bottom in the direction of the acceleration vector, a sphere scale vane tank is used to study the liquid-gas interface behaviors with different acceleration vector and different filling independently and we obtain a series of stable equilibrium interface and relocation time. We find that there is an obvious sedimentation in the direction of acceleration vector when fill rate greater than 2% fill. Suggestions have been put forward that outer vanes transferring liquid to the outlet should be fixed and small holes should be dogged at the vane close to the center post to improve the liquid flow between different vanes when B0 is greater than 2.5. The research about liquid transport alone ribbon vanes is simulated though software Flow3D. The simulation process is verified by comparing the liquid lip and vapor-liquid interface obtained from drop tower experiment and simulation result when fill rate is 15%. Then the influence of fill rate, numbers of vanes and the gap between vane and wall is studied through the same simulate process. Vanes' configurations are also changed to study the effect on the lip and liquid volume below some section. Some suggestions are put forward for the design of vanes.

Numerical research on the effects of impeller pump-out vanes on axial force in a solid-liquid screw centrifugal pump

International Nuclear Information System (INIS)

Cheng, X R; Li, R N; Gao, Y; Guo, W L

2013-01-01

A commercial CFD code has been used to predict the performance of a screw centrifugal pump with pump-out vanes, especially when changing regularity of impeller axial force based on the solid-liquid two-phase flow. The Unsteady Reynolds Averaged Navier-Stokes (URANS) approach has been applied to solve the unsteady, incompressible, three-dimensional turbulent. The SIMPLEC algorithm, standard wall functions and mix two-phase flow model were applied. The RNG k ε-model was used to account the turbulence effects. By changing the number of impeller pump-out vanes and width, six different screw centrifugal pump numerical simulation projects were given, and each scheme in the different solid volume fraction were calculated respectively. The change rules of axial force, velocity and pressure distribution of flow field were obtained on the different condition and different volume fraction. The results showed that the axial forces values based solid-fluid two-phase greater than based single-phase clear water, but both changing regularity of the axial force were consistent; as same condition, the same solid-phase volume concentration, with the increase of pump-out vanes number or width, the impeller axial force increased as well. Meanwhile the number of the pump-out vanes and the width of pump-out vanes in balancing the impeller axial force, there are the most optimal value

Hot spot detection system for vanes or blades of a combustion turbine

Science.gov (United States)

Twerdochlib, M.

1999-02-02

This invention includes a detection system that can determine if a turbine component, such as a turbine vane or blade, has exceeded a critical temperature, such as a melting point, along any point along the entire surface of the vane or blade. This system can be employed in a conventional combustion turbine having a compressor, a combustor and a turbine section. Included within this system is a chemical coating disposed along the entire interior surface of a vane or blade and a closed loop cooling system that circulates a coolant through the interior of the vane or blade. If the temperature of the vane or blade exceeds a critical temperature, the chemical coating will be expelled from the vane or blade into the coolant. Since while traversing the closed loop cooling system the coolant passes through a detector, the presence of the chemical coating in the coolant will be sensed by the system. If the chemical coating is detected, this indicates that the vane or blade has exceeded a critical temperature. 5 figs.

Mixed H∞ and passive control for linear switched systems via hybrid control approach

Science.gov (United States)

Zheng, Qunxian; Ling, Youzhu; Wei, Lisheng; Zhang, Hongbin

2018-03-01

This paper investigates the mixed H∞ and passive control problem for linear switched systems based on a hybrid control strategy. To solve this problem, first, a new performance index is proposed. This performance index can be viewed as the mixed weighted H∞ and passivity performance. Then, the hybrid controllers are used to stabilise the switched systems. The hybrid controllers consist of dynamic output-feedback controllers for every subsystem and state updating controllers at the switching instant. The design of state updating controllers not only depends on the pre-switching subsystem and the post-switching subsystem, but also depends on the measurable output signal. The hybrid controllers proposed in this paper can include some existing ones as special cases. Combine the multiple Lyapunov functions approach with the average dwell time technique, new sufficient conditions are obtained. Under the new conditions, the closed-loop linear switched systems are globally uniformly asymptotically stable with a mixed H∞ and passivity performance index. Moreover, the desired hybrid controllers can be constructed by solving a set of linear matrix inequalities. Finally, a numerical example and a practical example are given.

Hybrid electrokinetic method applied to mix contaminated soil

Energy Technology Data Exchange (ETDEWEB)

Mansour, H.; Maria, E. [Dept. of Building Civil and Environmental Engineering, Concordia Univ., Montreal (Canada)

2001-07-01

Several industrials and municipal areas in North America are contaminated with heavy metals and petroleum products. This mix contamination presents a particularly difficult task for remediation when is exposed in clayey soil. The objective of this research was to find a method to cleanup mix contaminated clayey soils. Finally, a multifunctional hybrid electrokinetic method was investigated. Clayey soil was contaminated with lead and nickel (heavy metals) at the level of 1000 ppm and phenanthrene (PAH) of 600 ppm. Electrokinetic surfactant supply system was applied to mobilize, transport and removal of phenanthrene. A chelation agent (EDTA) was also electrokinetically supplied to mobilize heavy metals. The studies were performed on 8 lab scale electrokinetic cells. The mix contaminated clayey soil was subjected to DC total voltage gradient of 0.3 V/cm. Supplied liquids (surfactant and EDTA) were introduced in different periods of time (22 days, 42 days) in order to optimize the most excessive removal of contaminants. The ph, electrical parameters, volume supplied, and volume discharged was monitored continuously during each experiment. At the end of these tests soil and cathalyte were subjected to physico-chemical analysis. The paper discusses results of experiments including the optimal energy use, removal efficiency of phenanthrene, as well, transport and removal of heavy metals. The results of this study can be applied for in-situ hybrid electrokinetic technology to remediate clayey sites contaminated with petroleum product mixed with heavy metals (e.g. manufacture Gas Plant Sites). (orig.)

A new wind vane for the measurement of atmospheric turbulence

Energy Technology Data Exchange (ETDEWEB)

Parker, M.J.; Heverly, M.

1997-02-01

A Cooperative Research and Development Agreement (CRADA) between Met One Instruments, Incorporated (Met One) and Westinghouse Savannah River Company (WSRC) was created to develop a new wind vane that more accurately measures atmospheric turbulence. Through a process that had several phases, Met One created a prototype vane that was designed to attach to the existing Model 1585 Bi-Directional Wind Vane instrument structure. The prototype contained over 20% less mass to enhance responsiveness, which was also increased through the use of a teardrop-shaped fin structure. The prototype vane can be readily manufactured for commercial retail. Tests in wind tunnel of Building 735-7A, the Meteorological Engineering Facility, indicated that the new vane has a superior starting threshold of less than 0.14 meter per second, a delay distance of 0.72 meter, and a damping ratio of 0.4. The relative accuracy of less than one degree is unchanged from the previous design. The vane bias was acceptable at 0.8 degree for the horizontal wind angle, but was slightly high at 1.4 degree for the verticle wind angle. The high value of the verticle wind angle bias can most likely be reduced to the desired less than one degree value with standard manufacturing production techniques. The durability of the prototype vane was not tested in the field but is expected to be slightly less due to the use of hollow rather than foam-filled fins. However, the loss of some durability is more than compensated with increased sensitivity at low wind speeds. Field testing of the prototype is required to test for adequacy of durability.

Groundwater flow analysis using mixed hybrid finite element method for radioactive waste disposal facilities

International Nuclear Information System (INIS)

Aoki, Hiroomi; Shimomura, Masanori; Kawakami, Hiroto; Suzuki, Shunichi

2011-01-01

In safety assessments of radioactive waste disposal facilities, ground water flow analysis are used for calculating the radionuclide transport pathway and the infiltration flow rate of groundwater into the disposal facilities. For this type of calculations, the mixed hybrid finite element method has been used and discussed about the accuracy of ones in Europe. This paper puts great emphasis on the infiltration flow rate of groundwater into the disposal facilities, and describes the accuracy of results obtained from mixed hybrid finite element method by comparing of local water mass conservation and the reliability of the element breakdown numbers among the mixed hybrid finite element method, finite volume method and nondegenerated finite element method. (author)

A lightweight, biological structure with tailored stiffness: The feather vane.

Science.gov (United States)

Sullivan, Tarah N; Pissarenko, Andreï; Herrera, Steven A; Kisailus, David; Lubarda, Vlado A; Meyers, Marc A

2016-09-01

The flying feathers of birds are keratinous appendages designed for maximum performance with a minimum weight penalty. Thus, their design contains ingenious combinations of components that optimize lift, stiffness, aerodynamics, and damage resistance. This design involves two main parts: a central shaft that prescribes stiffness and lateral vanes which allows for the capture of air. Within the feather vane, barbs branch from the shaft and barbules branch from barbs, forming a flat surface which ensures lift. Microhooks at the end of barbules hold barbs tightly together, providing the close-knit, unified structure of the feather vane and enabling a repair of the structure through the reattachment of un-hooked junctions. Both the shaft and barbs are lightweight biological structures constructed of keratin using the common motif of a solid shell and cellular interior. The cellular core increases the resistance to buckling with little added weight. Here we analyze the detailed structure of the feather barb and, for the first time, explain its flexural stiffness in terms of the mechanics of asymmetric foam-filled beams subjected to bending. The results are correlated and validated with finite element modeling. We compare the flexure of single barbs as well as arrays of barbs and find that the interlocking adherence of barbs to one another enables a more robust structure due to minimized barb rotation during deflection. Thus, the flexure behavior of the feather vane can be tailored by the adhesive hooking between barbs, creating a system that mitigates damage. A simplified three-dimensional physical model for this interlocking mechanism is constructed by additive manufacturing. The exceptional architecture of the feather vane will motivate the design of bioinspired structures with tailored and unique properties ranging from adhesives to aerospace materials. Despite its importance to bird flight, literature characterizing the feather vane is extremely limited. The feather

Hybrid two fuel system nozzle with a bypass connecting the two fuel systems

Science.gov (United States)

Varatharajan, Balachandar [Cincinnati, OH; Ziminsky, Willy Steve [Simpsonville, SC; Yilmaz, Ertan [Albany, NY; Lacy, Benjamin [Greer, SC; Zuo, Baifang [Simpsonville, SC; York, William David [Greer, SC

2012-05-29

A hybrid fuel combustion nozzle for use with natural gas, syngas, or other types of fuels. The hybrid fuel combustion nozzle may include a natural gas system with a number of swozzle vanes and a syngas system with a number of co-annular fuel tubes.

The Causes and Evolutionary Consequences of Mixed Singing in Two Hybridizing Songbird Species (Luscinia spp.)

Science.gov (United States)

Vokurková, Jana; Petrusková, Tereza; Reifová, Radka; Kozman, Alexandra; Mořkovský, Libor; Kipper, Silke; Weiss, Michael; Reif, Jiří; Dolata, Paweł T.; Petrusek, Adam

2013-01-01

Bird song plays an important role in the establishment and maintenance of prezygotic reproductive barriers. When two closely related species come into secondary contact, song convergence caused by acquisition of heterospecific songs into the birds’ repertoires is often observed. The proximate mechanisms responsible for such mixed singing, and its effect on the speciation process, are poorly understood. We used a combination of genetic and bioacoustic analyses to test whether mixed singing observed in the secondary contact zone of two passerine birds, the Thrush Nightingale (Luscinia luscinia) and the Common Nightingale (L. megarhynchos), is caused by introgressive hybridization. We analysed song recordings of both species from allopatric and sympatric populations together with genotype data from one mitochondrial and seven nuclear loci. Semi-automated comparisons of our recordings with an extensive catalogue of Common Nightingale song types confirmed that most of the analysed sympatric Thrush Nightingale males were ‘mixed singers’ that use heterospecific song types in their repertoires. None of these ‘mixed singers’ possessed any alleles introgressed from the Common Nightingale, suggesting that they were not backcross hybrids. We also analysed songs of five individuals with intermediate phenotype, which were identified as F1 hybrids between the Thrush Nightingale female and the Common Nightingale male by genetic analysis. Songs of three of these hybrids corresponded to the paternal species (Common Nightingale) but the remaining two sung a mixed song. Our results suggest that although hybridization might increase the tendency for learning songs from both parental species, interspecific cultural transmission is the major proximate mechanism explaining the occurrence of mixed singers among the sympatric Thrush Nightingales. We also provide evidence that mixed singing does not substantially increase the rate of interspecific hybridization and discuss the

Development of a Hybrid RANS/LES Method for Turbulent Mixing Layers

Science.gov (United States)

Georgiadis, Nicholas J.; Alexander, J. Iwan D.; Reshotko, Eli

2001-01-01

Significant research has been underway for several years in NASA Glenn Research Center's nozzle branch to develop advanced computational methods for simulating turbulent flows in exhaust nozzles. The primary efforts of this research have concentrated on improving our ability to calculate the turbulent mixing layers that dominate flows both in the exhaust systems of modern-day aircraft and in those of hypersonic vehicles under development. As part of these efforts, a hybrid numerical method was recently developed to simulate such turbulent mixing layers. The method developed here is intended for configurations in which a dominant structural feature provides an unsteady mechanism to drive the turbulent development in the mixing layer. Interest in Large Eddy Simulation (LES) methods have increased in recent years, but applying an LES method to calculate the wide range of turbulent scales from small eddies in the wall-bounded regions to large eddies in the mixing region is not yet possible with current computers. As a result, the hybrid method developed here uses a Reynolds-averaged Navier-Stokes (RANS) procedure to calculate wall-bounded regions entering a mixing section and uses a LES procedure to calculate the mixing-dominated regions. A numerical technique was developed to enable the use of the hybrid RANS-LES method on stretched, non-Cartesian grids. With this technique, closure for the RANS equations is obtained by using the Cebeci-Smith algebraic turbulence model in conjunction with the wall-function approach of Ota and Goldberg. The LES equations are closed using the Smagorinsky subgrid scale model. Although the function of the Cebeci-Smith model to replace all of the turbulent stresses is quite different from that of the Smagorinsky subgrid model, which only replaces the small subgrid turbulent stresses, both are eddy viscosity models and both are derived at least in part from mixing-length theory. The similar formulation of these two models enables the RANS

Numerical modelling of multi-vane expander operating conditions in ORC system

Science.gov (United States)

Rak, Józef; Błasiak, Przemysław; Kolasiński, Piotr

2017-11-01

Multi-vane expanders are positive displacement volumetric machines which are nowadays considered for application in micro-power domestic ORC systems as promising alternative to micro turbines and other volumetric expanders. The multi-vane expander features very simple design, low gas flow capacity, low expansion ratios, an advantageous ratio of the power output to the external dimensions and are insensitive to the negative influence of the gas-liquid mixture expansion. Moreover, the multi-vane expander can be easily hermetically sealed, which is one of the key issues in the ORC system design. A literature review indicates that issues concerning the application of multi-vane expanders in such systems, especially related to operating of multi-vane expander with different low-boiling working fluids, are innovative, not fully scientifically described and have the potential for practical implementation. In this paper the results of numerical investigations on multi-vane expander operating conditions are presented. The analyses were performed on three-dimensional numerical model of the expander in ANSYS CFX software. The numerical model of the expander was validated using the data obtained from the experiment carried out on a lab test-stand. Then a series of computational analysis were performed using expanders' numerical model in order to determine its operating conditions under various flow conditions of different working fluids.

Online soft sensor for hybrid systems with mixed continuous and discrete measurements

Czech Academy of Sciences Publication Activity Database

Suzdaleva, Evgenia; Nagy, Ivan

2012-01-01

Roč. 36, č. 10 (2012), s. 294-300 ISSN 0098-1354 R&D Projects: GA MŠk 1M0572; GA TA ČR TA01030123 Grant - others:Skoda Auto, a.s.(CZ) ENS/2009/UTIA Institutional research plan: CEZ:AV0Z10750506 Keywords : online state prediction * hybrid filter * state-space model * mixed data Subject RIV: BC - Control Systems Theory Impact factor: 2.091, year: 2012 http://library.utia.cas.cz/separaty/2011/AS/suzdaleva-online soft sensor for hybrid systems with mixed continuous and discrete measurements.pdf

Analysis of subgrid scale mixing using a hybrid LES-Monte-Carlo PDF method

International Nuclear Information System (INIS)

Olbricht, C.; Hahn, F.; Sadiki, A.; Janicka, J.

2007-01-01

This contribution introduces a hybrid LES-Monte-Carlo method for a coupled solution of the flow and the multi-dimensional scalar joint pdf in two complex mixing devices. For this purpose an Eulerian Monte-Carlo method is used. First, a complex mixing device (jet-in-crossflow, JIC) is presented in which the stochastic convergence and the coherency between the scalar field solution obtained via finite-volume methods and that from the stochastic solution of the pdf for the hybrid method are evaluated. Results are compared to experimental data. Secondly, an extensive investigation of the micromixing on the basis of assumed shape and transported SGS-pdfs in a configuration with practical relevance is carried out. This consists of a mixing chamber with two opposite rows of jets penetrating a crossflow (multi-jet-in-crossflow, MJIC). Some numerical results are compared to available experimental data and to RANS based results. It turns out that the hybrid LES-Monte-Carlo method could achieve a detailed analysis of the mixing at the subgrid level

Hybrid electrokinetics for separation, mixing, and concentration of colloidal particles

International Nuclear Information System (INIS)

Sin, Mandy L Y; Shimabukuro, Yusuke; Wong, Pak Kin

2009-01-01

The advent of nanotechnology has facilitated the preparation of colloidal particles with adjustable sizes and the control of their size-dependent properties. Physical manipulation, such as separation, mixing, and concentration, of these colloidal particles represents an essential step for fully utilizing their potential in a wide spectrum of nanotechnology applications. In this study, we investigate hybrid electrokinetics, the combination of dielectrophoresis and electrohydrodynamics, for active manipulation of colloidal particles ranging from nanometers to micrometers in size. A concentric electrode configuration, which is optimized for generating electrohydrodynamic flow, has been designed to elucidate the effectiveness of hybrid electrokinetics and define the operating regimes for different microfluidic operations. The results indicate that the relative importance of electrohydrodynamics increases with decreasing particle size as predicted by a scaling analysis and that electrohydrodynamics is pivotal for manipulating nanoscale particles. Using the concentric electrodes, we demonstrate separation, mixing, and concentration of colloidal particles by adjusting the relative strengths of different electrokinetic phenomena. The effectiveness of hybrid electrokinetics indicates its potential to serve as a generic technique for active manipulation of colloidal particles in various nanotechnology applications.

Split coaxial RFQ structure with modulated vanes

International Nuclear Information System (INIS)

Arai, S.

1983-10-01

A new split coaxial RFO structure with modulated vanes is proposed. The structure is designed to accelerate 238 U 4+ from 1.68 keV/u to 45.1 keV/u at frequency of 12.5 MHz. The cavity is 1.6 m in diameter and 8 m in length. The cavity consists of four cavity modules divided by three stems which support horizontal and vertical vanes periodically and alternatively. At the same time, problems on the beam dynamics and design procedures are described and discussed. (orig.)

Numerical analysis and experiment research on fluid orbital performance of vane type propellant management device

International Nuclear Information System (INIS)

Hu, Q; Li, Y; Pan, H L; Liu, J T; Zhuang, B T

2015-01-01

Vane type propellant management device (PMD) is one of the key components of the vane-type surface tension tank (STT), and its fluid orbital performance directly determines the STT's success or failure. In present paper, numerical analysis and microgravity experiment study on fluid orbital performance of a vane type PMD were carried out. By using two-phase flow model of volume of fluid (VOF), fluid flow characteristics in the tank with the vane type PMD were numerically calculated, and the rules of fluid transfer and distribution were gotten. A abbreviate model test system of the vane type PMD is established and microgravity drop tower tests were performed, then fluid management and transmission rules of the vane type PMD were obtained under microgravity environment. The analysis and tests results show that the vane type PMD has good and initiative fluid orbital management ability and meets the demands of fluid orbital extrusion in the vane type STT. The results offer valuable guidance for the design and optimization of the new generation of vane type PMD, and also provide a new approach for fluid management and control in space environment

Fluid-structure coupling in the guide vanes cascade of a pump-turbine scale model

International Nuclear Information System (INIS)

Roth, S; Hasmatuchi, V; Botero, F; Farhat, M; Avellan, F

2010-01-01

The present study concerns fluid-structure coupling phenomena occurring in a guide vane cascade of a pump-turbine scale model placed in the EPFL PF3 test rig. An advanced instrument set is used to monitor both vibrating structures and the surrounding flow. The paper highlights the interaction between vibrating guide vanes and the flow behavior. The pressure fluctuations in the stay vanes region are found to be strongly influenced by the amplitude of the vibrating guide vanes. Moreover, the flow induces different hydrodynamic damping on the vibrating guide vanes depending on the operating point of the pump-turbine.

Fluid-structure coupling in the guide vanes cascade of a pump-turbine scale model

Science.gov (United States)

Roth, S.; Hasmatuchi, V.; Botero, F.; Farhat, M.; Avellan, F.

2010-08-01

The present study concerns fluid-structure coupling phenomena occurring in a guide vane cascade of a pump-turbine scale model placed in the EPFL PF3 test rig. An advanced instrument set is used to monitor both vibrating structures and the surrounding flow. The paper highlights the interaction between vibrating guide vanes and the flow behavior. The pressure fluctuations in the stay vanes region are found to be strongly influenced by the amplitude of the vibrating guide vanes. Moreover, the flow induces different hydrodynamic damping on the vibrating guide vanes depending on the operating point of the pump-turbine.

Numerical modelling of multi-vane expander operating conditions in ORC system

Directory of Open Access Journals (Sweden)

Rak Józef

2017-01-01

Full Text Available Multi-vane expanders are positive displacement volumetric machines which are nowadays considered for application in micro-power domestic ORC systems as promising alternative to micro turbines and other volumetric expanders. The multi-vane expander features very simple design, low gas flow capacity, low expansion ratios, an advantageous ratio of the power output to the external dimensions and are insensitive to the negative influence of the gas-liquid mixture expansion. Moreover, the multi-vane expander can be easily hermetically sealed, which is one of the key issues in the ORC system design. A literature review indicates that issues concerning the application of multi-vane expanders in such systems, especially related to operating of multi-vane expander with different low-boiling working fluids, are innovative, not fully scientifically described and have the potential for practical implementation. In this paper the results of numerical investigations on multi-vane expander operating conditions are presented. The analyses were performed on three-dimensional numerical model of the expander in ANSYS CFX software. The numerical model of the expander was validated using the data obtained from the experiment carried out on a lab test-stand. Then a series of computational analysis were performed using expanders' numerical model in order to determine its operating conditions under various flow conditions of different working fluids.

Vane-Cam - camshaft controls with new functionalities; Vane-Cam - Nockenwellenversteller mit neuen Funktionalitaeten

Energy Technology Data Exchange (ETDEWEB)

Knecht, A.; Pohl, D. [Hydraulik-Ring GmbH, Nuertingen (Germany); Hannibal, W. [Fachhochschule Suedwestfalen, Iserlohn (Germany). Labor fuer Konstruktion und CAE-Anwendungen; enTec Consulting GmbH, Hemer (Germany)

2007-01-15

Infinitely variable camshaft phasing systems will be used in the future in practically all gasoline internal combustion engines high volume production. This paper of Hydraulik-Ring GmbH gives an overview of the current system concepts of the latest generation of camshaft controls utilizing the principle of the vane motor. (orig.)

The Screw-Conveyor Vane Design for Piece-Wise Construction ...

African Journals Online (AJOL)

Such a method of manufacture is beyond the resources of a general-purpose metal workshop that may require the odd spiral vane once in a while and can neither afford the time nor the cost of ordering from abroad. In this article the method of six blanks which the author has developed for the building up of the vane ...

A horizontal vane radiometer: experiment, theory and simulation

OpenAIRE

Wolfe, David; Lazarra, Andres; Garcia, Alejandro

2015-01-01

The existence of two motive forces on a Crookes radiometer has complicated the investigation of either force independently. The thermal creep shear force in particular has been subject to differing interpretations of the direction in which it acts and its order of magnitude. In this article we provide a horizontal vane radiometer design which isolates the thermal creep shear force. The horizontal vane radiometer is explored through experiment, kinetic theory, and the Direct Simulation Monte C...

Vane fabrication for the proof-of-principle radio-frequency quadrupole accelerator

International Nuclear Information System (INIS)

Williams, S.W.; Potter, J.M.

1981-01-01

The electrodes for the Proof-of-Principle (POP) Radio-Frequency Quadrupole (RFQ) accelerator were machined on a numerically controlled, three-axis, vertical mill. These pole tips, or vanes, were prepared for, and used, in the successful demonstration of RFQ practicality at Los Alamos National Laboratory in February 1980. The data set that described the vanes contained about 10 million bits of tool position data. The vanes were cut from OFHC copper blanks. The tolerances achieved were approximately +- 0.005 cm. The design and manufacturing procedures are described

Solar updraft power generator with radial and curved vanes

Science.gov (United States)

Hafizh, Hadyan; Hamsan, Raziff; Zamri, Aidil Azlan Ahmad; Keprawi, Mohamad Fairuz Mohamad; Shirato, Hiromichi

2018-02-01

Solar radiation is the largest source of energy available on earth and the solar updraft power generator (SUPG) is a renewable energy facility capable of harnessing its abundant power. Unlike the conventional wind turbines that harness natural wind in the atmosphere and often encounter with the intermittent issue or even complete cut-off from airflow, the SUPG creates artificial wind as a result of solar-induced convective flows. However, the SUPG has an inherent low total efficiency due to the conversion of thermal energy into pressure energy. Acknowledging the low efficiency and considering its potential as a renewable energy facility, the current work aims to increase the total efficiency by installing a series of guide walls inside the collector. Two types of guide walls were used i.e. radial and curved vanes. The result with curved vanes showed that the updraft velocity is higher compare to those without vanes. About 18% and 64% improvement of updraft velocity and mechanical power were attained respectively. Furthermore, it was observed that the role of radial vanes configuration was more to produce a smooth updraft velocity profile rather than increasing the total efficiency.

Water table tests of proposed heat transfer tunnels for small turbine vanes

Science.gov (United States)

Meitner, P. L.

1974-01-01

Water-table flow tests were conducted for proposed heat-transfer tunnels which were designed to provide uniform flow into their respective test sections of a single core engine turbine vane and a full annular ring of helicopter turbine vanes. Water-table tests were also performed for the single-vane test section of the core engine tunnel. The flow in the heat-transfer tunnels was shown to be acceptable.

Testing of Composite Fan Vanes With Erosion-Resistant Coating Accelerated

Science.gov (United States)

Bowman, Cheryl L.; Sutter, James K.; Otten, Kim D.; Samorezov, Sergey; Perusek, Gail P.

2004-01-01

The high-cycle fatigue of composite stator vanes provided an accelerated life-state prior to insertion in a test stand engine. The accelerated testing was performed in the Structural Dynamics Laboratory at the NASA Glenn Research Center under the guidance of Structural Mechanics and Dynamics Branch personnel. Previous research on fixturing and test procedures developed at Glenn determined that engine vibratory conditions could be simulated for polymer matrix composite vanes by using the excitation of a combined slip table and electrodynamic shaker in Glenn's Structural Dynamics Laboratory. Bench-top testing gave researchers the confidence to test the coated vanes in a full-scale engine test.

Biochar as a substitute for vermiculite in potting mix for hybrid poplar

Science.gov (United States)

William L. Headlee; Catherine E. Brewer; Richard B. Hall

2014-01-01

The purpose of this study was to evaluate biochar as a substitute for vermiculite in potting mixes for unrooted vegetative cuttings of hybrid poplar as represented by the clone ‘NM6’ (Populus nigra L. × Populus suaveolens Fischer subsp. maximowiczii A. Henry). We compared three treatments (peat moss (control), peat moss mixed with vermiculite, and peat moss mixed with...

Theoretical morphology and development of flight feather vane asymmetry with experimental tests in parrots.

Science.gov (United States)

Feo, Teresa J; Prum, Richard O

2014-06-01

Asymmetry in flight feather vane width is a major functional innovation associated with the evolution of flight in the ancestors of birds. However, the developmental and morphological basis of feather shape is not simple, and the developmental processes involved in vane width asymmetry are poorly understood. We present a theoretical model of feather morphology and development that describes the possible ways to modify feather development and produce vane asymmetry. Our model finds that the theoretical morphospace of feather shape is redundant, and that many different combinations of parameters could be responsible for vane asymmetry in a given feather. Next, we empirically measured morphological and developmental model parameters in asymmetric and symmetric feathers from two species of parrots to identify which combinations of parameters create vane asymmetry in real feathers. We found that both longer barbs, and larger barb angles in the relatively wider trailing vane drove asymmetry in tail feathers. Developmentally, longer barbs were the result of an offset of the radial position of the new barb locus, whereas larger barb angles were produced by differential expansion of barbs as the feather unfurls from the tubular feather germ. In contrast, the helical angle of barb ridge development did not contribute to vane asymmetry and could be indicative of a constraint. This research provides the first comprehensive description of both the morphological and developmental modifications responsible for vane asymmetry within real feathers, and identifies key steps that must have occurred during the evolution of vane asymmetry. © 2014 Wiley Periodicals, Inc.

Interaction of impeller and guide vane in a series-designed axial-flow pump

International Nuclear Information System (INIS)

Kim, S; Choi, Y S; Lee, K Y; Kim, J H

2012-01-01

In this paper, the interaction of the impeller and guide vane in a series-designed axial-flow pump was examined through the implementation of a commercial CFD code. The impeller series design refers to the general design procedure of the base impeller shape which must satisfy the various flow rate and head requirements by changing the impeller setting angle and number of blades of the base impeller. An arc type meridional shape was used to keep the meridional shape of the hub and shroud with various impeller setting angles. The blade angle and the thickness distribution of the impeller were designed as an NACA airfoil type. In the design of the guide vane, it was necessary to consider the outlet flow condition of the impeller with the given setting angle. The meridional shape of the guide vane were designed taking into consideration the setting angle of the impeller, and the blade angle distribution of the guide vane was determined with a traditional design method using vane plane development. In order to achieve the optimum impeller design and guide vane, three-dimensional computational fluid dynamics and the DOE method were applied. The interaction between the impeller and guide vane with different combination set of impeller setting angles and number of impeller blades was addressed by analyzing the flow field of the computational results.

Performance improvement of a centrifugal compressor stage by using different vaned diffusers

International Nuclear Information System (INIS)

Zhang, Y C; Kong, X Z; Li, F; Sun, W; Chen, Q G

2013-01-01

The vaneless diffuser (VLD) is usually adopted in the traditional design of the multi-stage centrifugal compressor because of the stage's match problem. The drawback of the stage with vaneless diffusers is low efficiency. In order to increase the efficiency and at the same time, induce no significant decline in the operating range of the stage, three different types of vaned diffusers are designed and numerically investigated: the traditional vaned diffuser (TVD), the low-solidity cascade diffuser (LSD) and the partial-height vane diffuser (PVD). These three types of vaned diffusers have different influences on the performance of the centrifugal compressor. In the present investigation, the first part investigates the performance of a centrifugal compressor stage with three different vaned diffusers. The second part studies the influences of the height and the position of partial height vanes on the stage performance, and discusses the matching problem between the PVD and the downstream return channel. The stage investigated in this paper includes the impeller, the diffuser, the bend and the return channel. In the process of numerical investigation, the flow is assumed to be steady, and this process includes calculation and simulation. The calculation of 3-D turbulent flow in the stage uses the commercial CFD code NUMECA together with the Spalart-Allmaras turbulence model. The simulation of the computational region includes the impeller passages, the diffuser passages and return channel passages. The structure and surrounding region are assumed to have a perfect cyclic symmetry, so the single channel model and periodic boundary condition are applied at the middle of the passage, that is to reduce the calculation region to only one region. The investigation showed that the low-solidity cascade diffuser would be a better choice as a middle course for the first stage of the multistage centrifugal compressor. Besides, the influences of the height and the position

Experimental Study on Series Operation of Sliding Vane Pump and Centrifugal Pump

OpenAIRE

Li, Tao; Zhang, Weiming; Jiang, Ming; Li, Zhengyang

2013-01-01

A platform for sliding vane pump and centrifugal pump tests is installed to study the series operation of them under different characteristics of pipeline. Firstly, the sliding vane pump and the centrifugal pump work independently, and the performance is recorded. Then, the two types of pumps are combined together, with the sliding vane pump acting as the feeding pump. Comparison is made between the performance of the independently working pump and the performance of series operation pump. Re...

Numerical Analysis of a Centrifugal Fan for Improved Performance using Splitter Vanes

OpenAIRE

N. Yagnesh Sharma; K. Vasudeva Karanth

2009-01-01

The flow field in a centrifugal fan is highly complex with flow reversal taking place on the suction side of impeller and diffuser vanes. Generally performance of the centrifugal fan could be enhanced by judiciously introducing splitter vanes so as to improve the diffusion process. An extensive numerical whole field analysis on the effect of splitter vanes placed in discrete regions of suspected separation points is possible using CFD. This paper examines the effect of sp...

Hybrid simulation using mixed reality for interventional ultrasound imaging training.

Science.gov (United States)

Freschi, C; Parrini, S; Dinelli, N; Ferrari, M; Ferrari, V

2015-07-01

Ultrasound (US) imaging offers advantages over other imaging modalities and has become the most widespread modality for many diagnostic and interventional procedures. However, traditional 2D US requires a long training period, especially to learn how to manipulate the probe. A hybrid interactive system based on mixed reality was designed, implemented and tested for hand-eye coordination training in diagnostic and interventional US. A hybrid simulator was developed integrating a physical US phantom and a software application with a 3D virtual scene. In this scene, a 3D model of the probe with its relative scan plane is coherently displayed with a 3D representation of the phantom internal structures. An evaluation study of the diagnostic module was performed by recruiting thirty-six novices and four experts. The performances of the hybrid (HG) versus physical (PG) simulator were compared. After the training session, each novice was required to visualize a particular target structure. The four experts completed a 5-point Likert scale questionnaire. Seventy-eight percentage of the HG novices successfully visualized the target structure, whereas only 45% of the PG reached this goal. The mean scores from the questionnaires were 5.00 for usefulness, 4.25 for ease of use, 4.75 for 3D perception, and 3.25 for phantom realism. The hybrid US training simulator provides ease of use and is effective as a hand-eye coordination teaching tool. Mixed reality can improve US probe manipulation training.

Synthesis of the turbulent mixing in a rod bundle with vaned spacer grids based on the OECD-KAERI CFD benchmark exercise

International Nuclear Information System (INIS)

Lee, Jae Ryong; Kim, Jungwoo; Song, Chul-Hwa

2014-01-01

Highlights: • OECD/KAERI international CFD benchmark exercise was operated by KAERI. • The purpose is to validate relevant CFD codes based on the MATiS-H experiments. • Blind calculation results were synthesized in terms of mean velocity and RMS. • Quality of control volume rather than the number of it was emphasized. • Major findings were followed OECD/NEA CSNI report. - Abstract: The second international CFD benchmark exercise on turbulent mixing in a rod bundle has been launched by OECD/NEA, to validate relevant CFD (Computational Fluid Dynamics) codes and develop problem-specific Best Practice Guidelines (BPG) based on the KAERI (Korea Atomic Energy Research Institute) MATiS-H experiments on the turbulent mixing in a 5 × 5 rod array having two different types of vaned spacer grids: split and swirl types. For this 2nd international benchmark exercise (IBE-2), the MATiS-H testing provided a unique set of experimental data such as axial and lateral velocity components, turbulent intensity, and vorticity information. Blind CFD calculation results were submitted by twenty-five (25) participants to KAERI, who is the host organization of the IBE-2, and then analyzed and synthesized by comparing them with the MATiS-H data. Based on the synthesis of the results from both the experiments and blind CFD calculations for the IBE-2, and also by comparing with the IBE-1 benchmark exercise on the mixing in a T-junction, useful information for simulating this kind of complicated physical problem in a rod bundle was obtained. And some additional Best Practice Guidelines (BPG) are newly proposed. A summary of the synthesis results obtained in the IBE-2 is presented in this paper

Synthesis of the turbulent mixing in a rod bundle with vaned spacer grids based on the OECD-KAERI CFD benchmark exercise

Energy Technology Data Exchange (ETDEWEB)

Lee, Jae Ryong; Kim, Jungwoo; Song, Chul-Hwa, E-mail: chsong@kaeri.re.kr

2014-11-15

Highlights: • OECD/KAERI international CFD benchmark exercise was operated by KAERI. • The purpose is to validate relevant CFD codes based on the MATiS-H experiments. • Blind calculation results were synthesized in terms of mean velocity and RMS. • Quality of control volume rather than the number of it was emphasized. • Major findings were followed OECD/NEA CSNI report. - Abstract: The second international CFD benchmark exercise on turbulent mixing in a rod bundle has been launched by OECD/NEA, to validate relevant CFD (Computational Fluid Dynamics) codes and develop problem-specific Best Practice Guidelines (BPG) based on the KAERI (Korea Atomic Energy Research Institute) MATiS-H experiments on the turbulent mixing in a 5 × 5 rod array having two different types of vaned spacer grids: split and swirl types. For this 2nd international benchmark exercise (IBE-2), the MATiS-H testing provided a unique set of experimental data such as axial and lateral velocity components, turbulent intensity, and vorticity information. Blind CFD calculation results were submitted by twenty-five (25) participants to KAERI, who is the host organization of the IBE-2, and then analyzed and synthesized by comparing them with the MATiS-H data. Based on the synthesis of the results from both the experiments and blind CFD calculations for the IBE-2, and also by comparing with the IBE-1 benchmark exercise on the mixing in a T-junction, useful information for simulating this kind of complicated physical problem in a rod bundle was obtained. And some additional Best Practice Guidelines (BPG) are newly proposed. A summary of the synthesis results obtained in the IBE-2 is presented in this paper.

Robustness of third family solutions for hybrid stars against mixed phase effects

Science.gov (United States)

Ayriyan, A.; Bastian, N.-U.; Blaschke, D.; Grigorian, H.; Maslov, K.; Voskresensky, D. N.

2018-04-01

We investigate the robustness of third family solutions for hybrid compact stars with a quark matter core that correspond to the occurrence of high-mass twin stars against a softening of the phase transition by means of a construction that mimics the effects of pasta structures in the mixed phase. We consider a class of hybrid equations of state that exploits a relativistic mean-field model for the hadronic as well as for the quark matter phase. We present parametrizations that correspond to branches of high-mass twin star pairs with maximum masses between 2.05 M⊙ and 1.48 M⊙ having radius differences between 3.2 and 1.5 km, respectively. When compared to a Maxwell construction with a fixed value of critical pressure Pc, the effect of the mixed phase construction consists in the occurrence of a region of pressures around Pc belonging to the coexistence of hadronic and quark matter phases between the onset pressure at PH and the end of the transition at PQ. The maximum broadening which would still allow mass-twin compact stars is found to be (PQ-PH)max≈Pc for all parametrizations within the present class of models. At least the heavier of the neutron stars of the binary merger GW170817 could have been a member of the third family of hybrid stars. We present the example of another class of hybrid star equations of state for which the appearance of the third family branch is not as robust against mixed phase effects as that of the present work.

The Hybrid Treatment Process for treatment of mixed radioactive and hazardous wastes

International Nuclear Information System (INIS)

Ross, W.A.; Kindle, C.H.

1992-04-01

This paper describes a new process for treating mixed hazardous and radioactive waste, commonly called mixed waste. The process is called the Hybrid Treatment Process (HTP), so named because it is built on the 20 years of experience with vitrification of wastes in melters, and the 12 years of experience with treatment of wastes by the in situ vitrification (ISV) process

Design and experimental validation of the inlet guide vane system of a mini hydraulic bulb-turbine

Energy Technology Data Exchange (ETDEWEB)

Ferro, L.M.C. [Department of Mechanical Engineering, Escola Superior de Tecnologia de Setubal, Polytechnic Institute of Setubal, Campus do IPS, Estefanilha, 2910-761 Setubal (Portugal); IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais,1049-001 Lisboa (Portugal); Gato, L.M.C.; Falcao, A.F.O. [IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais,1049-001 Lisboa (Portugal)

2010-09-15

The paper presents a fast design method for the inlet guide vanes of low-cost mini hydraulic bulb turbines. The guide vanes are positioned between two conical surfaces with a common vertex and have constant thickness distribution, except close to the leading and the trailing edges. The conical-walled inlet guide vane row is designed using a quasi-three-dimensional calculation method, by prescribing the angular-momentum distribution along the span at the outlet section of the guide vanes. The meridional through-flow is computed by a streamline curvature method and the blade-to-blade flow by a singularity surface method. The stagger angle and the vane camber are computed to fulfil the required design circulation and zero-incidence flow at the leading edge. The final vane shape is a single-curvature surface with straight leading and trailing edges. To validate the design method, a conical-walled inlet guide vane row nozzle-model with six fixed vanes was designed, manufactured and tested in an airflow rig. Traversing measurements along the circumferential and radial directions were made with a five-hole probe. The experimental results are compared with the prescribed design conditions and with numerical results from the three-dimensional inviscid and viscous flow computed with the FLUENT code. (author)

Research and development on the hydraulic design system of the guide vanes of multistage centrifugal pumps

International Nuclear Information System (INIS)

Zhang, Q H; Xu, Y; Shi, W D; Lu, W G

2012-01-01

To improve the hydraulic design accuracy and efficiency of the guide vanes of the multistage centrifugal pumps, four different-structured guide vanes are investigated, and the design processes of those systems are established. The secondary development platforms of the ObjectArx2000 and the UG/NX OPEN are utilized to develop the hydraulic design systems of the guide vanes. The error triangle method is adopted to calculate the coordinates of the vanes, the profiles of the vanes are constructed by Bezier curves, and then the curves of the flow areas along the flow-path are calculated. Two-dimensional and three-dimensional hydraulic models can be developed by this system.

ESRC guide vanes of hydraulic turbine for Three Gorges project

Directory of Open Access Journals (Sweden)

Rui CHEN

2005-05-01

Full Text Available The mechanical properties and internal quality of low carbon martensite Electroslag Remelting Casting (ESRCstainless steel castings are superior to that of sand casting ones. The key technologies for the equipments and ESRC processes have been resolved during the experimental research period of guide vanes of hydraulic turbines for Three Gorges project. And ESRC guide vanes of hydraulic turbines for Three Gorges project have been produced successfully.

Intermodal parametric gain of degenerate four wave mixing in large mode area hybrid photonic crystal fibers

DEFF Research Database (Denmark)

Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

2013-01-01

Intermodal degenerate four wave mixing (FWM) is investigated numerically in large mode area hybrid photonic crystal fibers. The dispersion is controlled independently of core size, and thus allows for power scaling of the FWM process.......Intermodal degenerate four wave mixing (FWM) is investigated numerically in large mode area hybrid photonic crystal fibers. The dispersion is controlled independently of core size, and thus allows for power scaling of the FWM process....

Computer aided design and development of mixed-propeller pumps

International Nuclear Information System (INIS)

Bhaoyal, B.C.

1994-01-01

This paper deals with the design principle of mixed propeller hydraulic aided by CADD software developed by author for generation of the hydraulic profile of the mixed propeller and diffuser geometry. The design methodology for plotting the vane profile of mixed propeller pump has been discussed in detail with special reference to conformal transformation in cylindrical as well as conical plane. (author). 10 refs., 11 figs

Study of turbine and guide vanes integration to enhance the performance of cross flow vertical axis wind turbine

Science.gov (United States)

Wibowo, Andreas; Tjahjana, Dominicus Danardono Dwi Prija; Santoso, Budi; Situmorang, Marcelinus Risky Clinton

2018-02-01

The main purpose of this study is to investigate the best configuration between guide vanes and cross flow vertical axis wind turbine with variation of several parameters including guide vanes tilt angle and the number of turbine and guide vane blades. The experimental test were conducted under various wind speed and directions for testing cross flow wind turbine, consisted of 8, 12 and 16 blades. Two types of guide vane were developed in this study, employing 20° and 60° tilt angle. Both of the two types of guide vane had three variations of blade numbers which had same blade numbers variations as the turbines. The result showed that the configurations between 60° guide vane with 16 blade numbers and turbine with 16 blade numbers had the best configurations. The result also showed that for certain configuration, guide vane was able to increase the power generated by the turbine significantly by 271.39% compared to the baseline configuration without using of guide vane.

The effect of additional equilibrium stress functions on the three-node hybrid-mixed curved beam element

International Nuclear Information System (INIS)

Kim, Jin Gon; Park, Yong Kuk

2008-01-01

To develop an effective hybrid-mixed element, it is extremely critical as to how to assume the stress field. This research article demonstrates the effect of additional equilibrium stress functions to enhance the numerical performance of the locking-free three-node hybrid-mixed curved beam element, proposed in Saleeb and Chang's previous work. It is exceedingly complicated or even infeasible to determine the stress functions to satisfy fully both the equilibrium conditions and suppression of kinematic deformation modes in the three-node hybrid-mixed formulation. Accordingly, the additional stress functions to satisfy partially or fully equilibrium conditions are incorporated in this study. Several numerical examples for static and dynamic problems confirm that the newly proposed element with these additional stress functions is highly effective regardless of the slenderness ratio and curvature of arches in static and dynamic analyses

Design and Analysis of a Split Deswirl Vane in a Two-Stage Refrigeration Centrifugal Compressor

Directory of Open Access Journals (Sweden)

Jeng-Min Huang

2014-09-01

Full Text Available This study numerically investigated the influence of using the second row of a double-row deswirl vane as the inlet guide vane of the second stage on the performance of the first stage in a two-stage refrigeration centrifugal compressor. The working fluid was R134a, and the turbulence model was the Spalart-Allmaras model. The parameters discussed included the cutting position of the deswirl vane, the staggered angle of two rows of vane, and the rotation angle of the second row. The results showed that the performance of staggered angle 7.5° was better than that of 15° or 22.5°. When the staggered angle was 7.5°, the performance of cutting at 1/3 and 1/2 of the original deswirl vane length was slightly different from that of the original vane but obviously better than that of cutting at 2/3. When the staggered angle was 15°, the cutting position influenced the performance slightly. At a low flow rate prone to surge, when the second row at a staggered angle 7.5° cutting at the half of vane rotated 10°, the efficiency was reduced by only about 0.6%, and 10% of the swirl remained as the preswirl of the second stage, which is generally better than other designs.

PURE OR HYBRID? THE DEVELOPMENT OF MIXED DICTIONARY GENRES

OpenAIRE

Reinhard R. K. Hartmann

2005-01-01

This paper explores 'hybrid' genres of dictionaries and other reference works. Against the tradition of general dictionaries becoming ever more specialised, there has also been a growing trend of mixing two or more 'pure' dictionary types for achieving specific purposes, e.g. the combination of alphabetic and thematic dictionary,general dictionary and technical glossary, dictionary and thesaurus, dictionary and encyclopedia, monolingual and bilingual dictionary, etc. Examples of these various...

CMC vane assembly apparatus and method

Science.gov (United States)

Schiavo, Anthony L; Gonzalez, Malberto F; Huang, Kuangwei; Radonovich, David C

2012-10-23

A metal vane core or strut (64) is formed integrally with an outer backing plate (40). An inner backing plate (38) is formed separately. A spring (74) with holes (75) is installed in a peripheral spring chamber (76) on the strut. Inner and outer CMC shroud covers (46, 48) are formed, cured, then attached to facing surfaces of the inner and outer backing plates (38, 40). A CMC vane airfoil (22) is formed, cured, and slid over the strut (64). The spring (74) urges continuous contact between the strut (64) and airfoil (66), eliminating vibrations while allowing differential expansion. The inner end (88) of the strut is fastened to the inner backing plate (38). A cooling channel (68) in the strut is connected by holes (69) along the leading edge of the strut to peripheral cooling paths (70, 71) around the strut. Coolant flows through and around the strut, including through the spring holes.

Performance improvement of centrifugal compressor stage with pinched geometry or vaned diffuser

Energy Technology Data Exchange (ETDEWEB)

Jaatinen, A.

2009-07-01

Centrifugal compressors are widely used for example in refrigeration processes, the oil and gas industry, superchargers, and waste water treatment. In this work, five different vaneless diffusers and six different vaned diffusers are investigated numerically. The vaneless diffusers vary only by their diffuser width, so that four of the geometries have pinch implemented to them. Pinch means a decrease in the diffuser width. Four of the vaned diffusers have the same vane turning angle and a different number of vanes, and two have different vane turning angles. The flow solver used to solve the flow fields is Finfo, which is a Navier-Stokes solver. All the cases are modeled Chien's k-epsilon turbulence model. All five vaneless diffusers and three vaned diffusers are investigated also experimentally. For each construction, the compressor operating map is measured according to relevant standards. In addition to this, the flow fields before and after the diffuser are measured with static and total pressure, flow angle and total temperature measurements k-omega SST turbulence model. The simulation results indicate that it is possible to improve the efficiency with the pinch, and according to the numerical results, the two best geometries are the ones with most pinch at the shroud. These geometries have approximately 4 percentage points higher effciency than the unpinched vaneless diffusers. The hub pinch does not seem to have any major benefits. In general, the pinches make the flow fields before and after the diffuser more uniform. The pinch also seems to improve the impeller effciency. This is down to two reasons. The major reason is that the pinch decreases the size of slow flow and possible backflow region located near the shroud after the impeller. Secondly, the pinches decrease the flow velocity in the tip clearance, leading to a smaller tip leakage flow and therefore slightly better impeller efficiency. Also some of the vaned diffusers improve the efficiency

Discussion on the re-irradiated fuel assembly with damaged guide vanes

International Nuclear Information System (INIS)

Li Ligang

2013-01-01

In January 2011, during the second plant of CNNC Nuclear Power Operations Management Co., Ltd.(hereinafter referred to as the second plant) refueling outage, the visual inspection found the guide vanes of fuel assembly A had felling off. After the National Nuclear Safety Administration (NNSA) estimated and approved, the fuel assembly A was reloaded in the specified location of reactor core. During the refueling outage in March 2012, the fuel assembly A was removed again from the reactor core. Visual inspection confirmed that the fuel assembly A was complete and without abnormal changes. The practice provides reference for re-irradiated of fuel assembly with the same type of damaged guide vanes, and provides case support for standard development for the same type of re-irradiated fuel assembly with damaged guide vanes. (author)

Turbofan gas turbine engine with variable fan outlet guide vanes

Science.gov (United States)

Wood, Peter John (Inventor); LaChapelle, Donald George (Inventor); Grant, Carl (Inventor); Zenon, Ruby Lasandra (Inventor); Mielke, Mark Joseph (Inventor)

2010-01-01

A turbofan gas turbine engine includes a forward fan section with a row of fan rotor blades, a core engine, and a fan bypass duct downstream of the forward fan section and radially outwardly of the core engine. The forward fan section has only a single stage of variable fan guide vanes which are variable fan outlet guide vanes downstream of the forward fan rotor blades. An exemplary embodiment of the engine includes an afterburner downstream of the fan bypass duct between the core engine and an exhaust nozzle. The variable fan outlet guide vanes are operable to pivot from a nominal OGV position at take-off to an open OGV position at a high flight Mach Number which may be in a range of between about 2.5-4+. Struts extend radially across a radially inwardly curved portion of a flowpath of the engine between the forward fan section and the core engine.

Investigation of mixing and diffusion processes in hybrid spot laser-MIG keyhole welding

International Nuclear Information System (INIS)

Zhou, J; Tsai, H L

2009-01-01

In hybrid laser-MIG keyhole welding, anti-crack elements can be added into the weld pool through a filler metal in anticipation of compensating mass loss, preventing porosity formation and improving compositional and mechanical properties of the welds. Understanding the mixing and diffusion of the filler metal in the molten pool is vital to achieve these desired objectives. In this study, mathematical models and associated numerical techniques have been developed to investigate the mixing and diffusion processes in hybrid laser-MIG keyhole welding. The transient interactions between droplets and weld pool and dynamics of the melt flow are studied. The effects of key process parameters, such as droplet size (wire diameter), droplet generation frequency (wire feed speed) and droplet impinging speed, on mixing/diffusion are systematically investigated. It was found that compositional homogeneity of the weld pool is determined by the competition between the mixing rate and the solidification rate. A small-size filler droplet together with high generation frequency can increase the latitudinal diffusion of the filler metal into the weld pool, while the large-size droplet along with the low generation frequency helps to get more uniform longitudinal diffusion. Increasing the impinging velocity of the filler droplet can improve the latitudinal diffusion of the filler metal. However, a high impinging velocity can cause a lower diffusion zone in the upper part of the welds. This study provides a good foundation for optimizing the hybrid laser-MIG keyhole welding process to achieve quality welds with desired properties.

Design and numerical investigation of swirl recovery vanes for the Fokker 29 propeller

Directory of Open Access Journals (Sweden)

Wang Yangang

2014-10-01

Full Text Available Swirl recovery vanes (SRVs are a set of stationary vanes located downstream from a propeller, which may recover some of the residual swirl from the propeller, hoping for an improvement in both thrust and efficiency. The SRV concept design for a scaled version representing the Fokker 29 propeller is performed in this paper, which may give rise to a promotion in propulsive performance of this traditional propeller. Firstly the numerical strategy is validated from two aspects of global quantities and the local flow field of the propeller compared with experimental data, and then the exit flow together with the development of propeller wake is analyzed in detail. Three kinds of SRV are designed with multiple circular airfoils. The numerical results show that the swirl behind the propeller is recovered significantly with Model V3, which is characterized by the highest solidity along spanwise, for various working conditions, and the combination of rotor and vane produced 5.76% extra thrust at the design point. However, a lower efficiency is observed asking for a better vane design and the choice of a working point. The vane position is studied which shows that there is an optimum range for higher thrust and efficiency.

Combining effect of optimized axial compressor variable guide vanes and bleed air on the thermodynamic performance of aircraft engine system

International Nuclear Information System (INIS)

Kim, Sangjo; Son, Changmin; Kim, Kuisoon

2017-01-01

Aim of this work is to provide evidence of the effectiveness of combined use of the variable guide vanes (VGVs) and bleed air on the thermodynamic performance of aircraft engine system. This paper performed the comparative study to evaluate the overall thermal performance of an aircraft engine with optimized VGVs and bleed air, separately or simultaneously. The low-bypass ratio turbofan engine has been modeled with a 0D/1D modeling approach. The genetic algorithm is employed to find the optimum schedule of VGVs and bleed air. There are four types of design variables: (1) the inlet guide vane (IGV) angle, (2) the IGV and 1st stator vane (SV) angles, (3) bleed air mass flow rate at the exit of the axial compressor, and (4) both type 2 and type 3. The optimization is conducted with surge margin constraints of more than 10% and 15% in the axial compressor. The results show that the additional use of the bleed air increases the efficiency of the compressors. Overall, the percentage reductions of the total fuel consumption for the engine with the IGV, 1st SV and bleed air schedule is 1.63% for 15% surge margin constraints when compared with the engine with the IGV schedule. - Highlights: • The effect of combined use of variable guide vanes and bleed air is evaluated. • The genetic algorithm is employed to find the optimum setting angle and bleed air. • A low bypass ratio mixed turbofan engine is analyzed for optimization. • Additional use of the bleed air shows improved overall performance of the engine.

Static thrust-vectoring performance of nonaxisymmetric convergent-divergent nozzles with post-exit yaw vanes. M.S. Thesis - George Washington Univ., Aug. 1988

Science.gov (United States)

Foley, Robert J.; Pendergraft, Odis C., Jr.

1991-01-01

A static (wind-off) test was conducted in the Static Test Facility of the 16-ft transonic tunnel to determine the performance and turning effectiveness of post-exit yaw vanes installed on two-dimensional convergent-divergent nozzles. One nozzle design that was previously tested was used as a baseline, simulating dry power and afterburning power nozzles at both 0 and 20 degree pitch vectoring conditions. Vanes were installed on these four nozzle configurations to study the effects of vane deflection angle, longitudinal and lateral location, size, and camber. All vanes were hinged at the nozzle sidewall exit, and in addition, some were also hinged at the vane quarter chord (double-hinged). The vane concepts tested generally produced yaw thrust vectoring angles much less than the geometric vane angles, for (up to 8 percent) resultant thrust losses. When the nozzles were pitch vectored, yawing effectiveness decreased as the vanes were moved downstream. Thrust penalties and yawing effectiveness both decreased rapidly as the vanes were moved outboard (laterally). Vane length and height changes increased yawing effectiveness and thrust ratio losses, while using vane camber, and double-hinged vanes increased resultant yaw angles by 50 to 100 percent.

Numerical and experimental study of the leakage flow in guide vanes with different hydrofoils

Directory of Open Access Journals (Sweden)

Sailesh Chitrakar

2017-07-01

Full Text Available Clearance gaps between guide vanes and cover plates of Francis turbines tend to increase in size due to simultaneous effect of secondary flow and erosion in sediment affected hydropower plants. The pressure difference between the two sides of the guide vane induces leakage flow through the gap. This flow enters into the suction side with high acceleration, disturbing the primary flow and causing more erosion and losses in downstream turbine components. A cascade rig containing a single guide vane passage has been built to study the effect of the clearance gap using pressure sensors and PIV (Particle Image Velocimetry technique. This study focuses on developing a numerical model of the test rig, validating the results with experiments and investigating the behavior of leakage flow numerically. It was observed from both CFD and experiment that the leakage flow forms a passage vortex, which shifts away from the wall while travelling downstream. The streamlines contributing to the formation of this vortex have been discussed. Furthermore, the reference guide vane with symmetrical hydrofoil has been compared with four cambered profiles, in terms of the guide vane loading and the consequent effect on the leakage flow. A dimensionless term called Leakage Flow Factor (Lff has been introduced to compare the performances of hydrofoils. It is shown that the leakage flow and its effect on increasing losses and erosion can be minimized by changing the pressure distribution over the guide vane.

Influence of blockage effect on measurement by vane anemometers

Directory of Open Access Journals (Sweden)

Sluse Jan

2017-01-01

Full Text Available The article deals with influence of blockage effect caused by vane anemometer in the wind tunnel by measurement via this anemometer. The influences will be represented by correction coefficient. The first part of this article is focused on the design of the impeller of vane anemometers. The impellers are printed on 3D printer with variable parameters. The anemometer is fixed in an open section of the wind tunnel with closed loop and the velocity profile is measured by Laser Doppler velocimetry (LDV in front and behind it for all impellers. The experimental data are compared with the numerical simulation in OpenFOAM. The results are correction coefficients.

Analysis on influence of guide vanes closure laws of pump-turbine on load rejection transient process

Science.gov (United States)

Yao, Z.; Bi, H. L.; Huang, Q. S.; Li, Z. J.; Wang, Z. W.

2013-12-01

In load rejection transient process, the sudden shut down of guide vanes may cause units speed rise and a sharp increase in water hammer pressure of diversion system, which endangers the safety operation of the power plant. Adopting reasonable guide vane closure law is a kind of economic and effective measurement to reduce the water hammer pressure and limit rotational speed increases. In this paper, combined with Guangzhou Pumped Storage Power Station plant A, the load rejection condition under different guide vanes closure laws is calculated and the key factor of guide vanes closure laws on the impact of the load rejection transition process is analyzed. The different inflection points, which are the closure modes, on the impact of unit speed change, water level fluctuation of surge tank, and the pressure fluctuation of volute inlet and draft tube inlet are further discussed. By compared with the calculation results, a reasonable guide vanes inflection point position can be determined according to security requirements and a reasonable guide vanes closure law can be attained to effectively coordinate the unit speed rise and the rapid pressure change in the load rejection transient process.

Effects of the friction coefficient on the torque characteristics of a hydraulic cam-rotor vane motor

Energy Technology Data Exchange (ETDEWEB)

Ma, Qiankun; Wang, Xuyong; Yuan, Fan; Chen, Liang Shen; Tao, Jian Feng [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai (China); Miao, Zhong Hua [School of Mechatronic Engineering and Automation, Shanghai University, Shanghai (China)

2016-08-15

The friction coefficient between the vane and the slot is one of the most critical factors that affects the performance of a continuous rotary hydraulic cam-rotor vane motor. To study the effects of this coefficient on the torque characteristics of the motor, the mathematical model for the normal force and the disturbing torque between the cam rotors and the vanes of the motor was established by analyzing the forces exerted on the vanes. The mathematical model was simulated with MATLAB, and simulation results show that an increase in the friction coefficient would simultaneously decrease the normal force and increase the disturbing torque, which would negatively affect the performance of the motor. Further experimental research indicated that the low-speed performance of the hydraulic cam-rotor motor was significantly improved when the friction coefficient was reduced by controlling the parallelism tolerance, flatness and roughness between the vanes and the slots.

Evaluation of effect of low opening operation on increasing wear of bearing bushings of guide vanes used in hydropower plants

International Nuclear Information System (INIS)

Kim, Jong Sung; Kim, Se Na

2012-01-01

A guide vane plays a key role in controlling the flow rate of water supplied to the turbine of a hydropower plant. It has been reported that guide vane bearing bushings are subjected to considerable wear, which requires them to be maintained. An ancillary service such as frequency control and black start causes cyclic low opening operation of the guide vanes. It is empirically well known that such operation increases the wear rate of the guide vane bearing bushing. In this study, the effect of low opening operation on the increasing wear of the guide vane bearing bushing is quantitatively assessed via finite element flow analysis, finite element stress analysis, and relative wear evaluation. As a result of the assessment, it is identified that the pressure applied on the guide vane surface increases and the contact length between the outer surface of the guide vane stem and the inner surface of the bearing bushing decreases with a decrease in the opening of the guide vane. In addition, low opening of the guide vanes results in an increase in the relative wear owing to the generation of high contact pressure on the bearing bushing surfaces

A three dimensional model of a vane rheometer

International Nuclear Information System (INIS)

Nazari, Behzad; Moghaddam, Ramin Heidari; Bousfield, Douglas

2013-01-01

Highlights: • FEM was used to calculate the isothermal flow parameters in a vane geometry. • Velocity, pressure and then stress fields were obtained. • Using total stress, shaft torque was calculated to compare with experimental data. • A modified cell Reynolds number and power number were used to study flow pattern. • A comparison between 2D and 3D modeling was done based on calculated torques. -- Abstract: Vane type geometries are often used in rheometers to avoid slippage between the sample and the fixtures. While yield stress and other rheological properties can be obtained with this geometry, a complete analysis of this complex flow field is lacking in the literature. In this work, a finite element method is used to calculate the isothermal flow parameters in a vane geometry. The method solves the mass and momentum continuity equations to obtain velocity, pressure and then stress fields. Using the total stress numerical data, we calculated the torque applied on solid surfaces. The validity of the computational model was established by comparing the results to experimental results of shaft torque at different angular velocities. The conditions where inertial terms become important and the linear relationship between torque and stress are quantified with dimensionless groups. The accuracy of a two dimensional analysis is compared to the three dimensional results

The image evaluation of iterative motion correction reconstruction algorithm PROPELLER T2-weighted imaging compared with MultiVane T2-weighted imaging

Science.gov (United States)

Lee, Suk-Jun; Yu, Seung-Man

2017-08-01

The purpose of this study was to evaluate the usefulness and clinical applications of MultiVaneXD which was applying iterative motion correction reconstruction algorithm T2-weighted images compared with MultiVane images taken with a 3T MRI. A total of 20 patients with suspected pathologies of the liver and pancreatic-biliary system based on clinical and laboratory findings underwent upper abdominal MRI, acquired using the MultiVane and MultiVaneXD techniques. Two reviewers analyzed the MultiVane and MultiVaneXD T2-weighted images qualitatively and quantitatively. Each reviewer evaluated vessel conspicuity by observing motion artifacts and the sharpness of the portal vein, hepatic vein, and upper organs. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated by one reviewer for quantitative analysis. The interclass correlation coefficient was evaluated to measure inter-observer reliability. There were significant differences between MultiVane and MultiVaneXD in motion artifact evaluation. Furthermore, MultiVane was given a better score than MultiVaneXD in abdominal organ sharpness and vessel conspicuity, but the difference was insignificant. The reliability coefficient values were over 0.8 in every evaluation. MultiVaneXD (2.12) showed a higher value than did MultiVane (1.98), but the difference was insignificant ( p = 0.135). MultiVaneXD is a motion correction method that is more advanced than MultiVane, and it produced an increased SNR, resulting in a greater ability to detect focal abdominal lesions.

Effect of Guide Vane Clearance Gap on Francis Turbine Performance

Directory of Open Access Journals (Sweden)

Ravi Koirala

2016-04-01

Full Text Available Francis turbine guide vanes have pivoted support with external control mechanism, for conversion of pressure to kinetic energy and to direct them to runner vanes. This movement along the support is dependent on variation of load and flow (operating conditions. Small clearance gaps between facing plates and the upper and lower guide vane tips are available to aid this movement, through which leakage flow occurs. This secondary flow disturbs the main flow stream, resulting performance loss. Additionally, these increased horseshoe vortex, in presence of sand, when crosses through the gaps, both the surfaces are eroded. This causes further serious effect on performance and structural property by increasing gaps. This paper discusses the observation of the severity in hydropower plants and effect of clearance gaps on general performance of the Francis turbine through computational methods. It also relates the primary result with the empirical relation for leakage flow prediction. Additionally, a possible method to computationally estimate thickness depletion has also been presented. With increasing clearance gap, leakage increases, which lowers energy conversion and turbine efficiency along with larger secondary vortex.

Performance of an alpha-vane and pitot tube in simulated heavy rain environment

Science.gov (United States)

Luers, J. K.; Fiscus, I. B.

1985-01-01

Experimental tests were conducted in the UDRI Environmental Wind/Rain Tunnel to establish the performance of an alpha-vane, that measures angle of attack, in a simulated heavy rain environment. The tests consisted of emersing the alpha-vane in an airstream with a concurrent water spray penetrating vertically through the airstream. The direction of the spray was varied to make an angle of 5.8 to 18 deg with the airstream direction in order to simulate the conditions that occur when an aircraft lands in a heavy rain environment. Rainrates simulated varied from 1000 to 1200 mm/hr which are the most severe ever expected to be encountered by an aircraft over even a 30 second period. Tunnel airspeeds ranged from 85 to 125 miles per hour. The results showed that even the most severe rainrates produced a misalignment in the alpha-vane of only 1 deg away from the airstream direction. Thus for normal rain conditions experienced by landing aircraft no significant deterioration in alpha-vane performance is expected.

Precision Model for Microwave Rotary Vane Attenuator

DEFF Research Database (Denmark)

Guldbrandsen, Tom

1979-01-01

A model for a rotary vane attenuator is developed to describe the attenuator reflection and transmission coefficients in detail. All the parameters of the model can be measured in situ, i.e., without diassembling any part. The tranmission errors caused by internal reflections are calculated from ...

Flow control in axial fan inlet guide vanes by synthetic jets

Directory of Open Access Journals (Sweden)

Wurst P.

2013-04-01

Full Text Available Tested high pressure axial flow fan with hub/tip ratio of 0.70 and external diameter of 600 mm consisted of inlet guide vanes (IGV, rotor and stator blade rows. Fan peripheral velocity was 47 m/s. Air volume flow rate was changed by turning of rear part of the inlet guide vanes. At turning of 20 deg the flow was separated on the IGV profiles. The synthetic jets were introduced through radial holes in machine casing in the location before flow separation origin. Synthetic jet actuator was designed with the use of a speaker by UT AVCR. Its membrane had diameter of 63 mm. Excitation frequency was chosen in the range of 500 Hz – 700 Hz. Synthetic jets favourably influenced separated flow on the vane profiles in the distance of (5 – 12 mm from the casing surface. The reduction of flow separation area caused in the region near the casing the decrease of the profile loss coefficient approximately by 20%.

Flow control in axial fan inlet guide vanes by synthetic jets

Science.gov (United States)

Cyrus, V.; Trávníček, Z.; Wurst, P.; Kordík, J.

2013-04-01

Tested high pressure axial flow fan with hub/tip ratio of 0.70 and external diameter of 600 mm consisted of inlet guide vanes (IGV), rotor and stator blade rows. Fan peripheral velocity was 47 m/s. Air volume flow rate was changed by turning of rear part of the inlet guide vanes. At turning of 20 deg the flow was separated on the IGV profiles. The synthetic jets were introduced through radial holes in machine casing in the location before flow separation origin. Synthetic jet actuator was designed with the use of a speaker by UT AVCR. Its membrane had diameter of 63 mm. Excitation frequency was chosen in the range of 500 Hz - 700 Hz. Synthetic jets favourably influenced separated flow on the vane profiles in the distance of (5 - 12) mm from the casing surface. The reduction of flow separation area caused in the region near the casing the decrease of the profile loss coefficient approximately by 20%.

Numerical Calculation and Experiment of Coupled Dynamics of the Differential Velocity Vane Pump Driven by the Hybrid Higher-order Fourier Non-circular Gears

Science.gov (United States)

Xu, Gaohuan; Chen, Jianneng; Zhao, Huacheng

2018-06-01

The transmission systems of the differential velocity vane pumps (DVVP) have periodic vibrations under loads. And it is not easy to find the reason. In order to optimize the performance of the pump, the authors proposed DVVP driven by the hybrid Higher-order Fourier non-circular gears and tested it. There were also similar periodic vibrations and noises under loads. Taking into account this phenomenon, the paper proposes fluid mechanics and solid mechanics simulation methodology to analyze the coupling dynamics between fluid and transmission system and reveals the reason. The results show that the pump has the reverse drive phenomenon, which is that the blades drive the non-circular gears when the suction and discharge is alternating. The reverse drive phenomenon leads the sign of the shaft torque to be changed in positive and negative way. So the transmission system produces torsional vibrations. In order to confirm the simulation results, micro strains of the input shaft of the pump impeller are measured by the Wheatstone bridge and wireless sensor technology. The relationships between strain and torque are obtained by experimental calibration, and then the true torque of input shaft is calculated indirectly. The experimental results are consistent to the simulation results. It is proven that the periodic vibrations are mainly caused by fluid solid coupling, which leads to periodic torsional vibration of the transmission system.

Experimental study of laminar mixed convection in a rod bundle with mixing vane spacer grids

Energy Technology Data Exchange (ETDEWEB)

Mohanta, Lokanath, E-mail: lxm971@psu.edu [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Cheung, Fan-Bill [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Bajorek, Stephen M.; Tien, Kirk; Hoxie, Chris L. [Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001 (United States)

2017-02-15

Highlights: • Investigated the heat transfer during mixed laminar convection in a rod bundle with linearly varying heat flux. • The Nusselt number increases downstream of the inlet with increasing Richardson number. • Developed an enhancement factor to account for the effects of mixed convection over the forced laminar heat transfer. - Abstract: Heat transfer by mixed convection in a rod bundle occurs when convection is affected by both the buoyancy and inertial forces. Mixed convection can be assumed when the Richardson number (Ri = Gr/Re{sup 2}) is on the order of unity, indicating that both forced and natural convection are important contributors to heat transfer. In the present study, data obtained from the Rod Bundle Heat Transfer (RBHT) facility was used to determine the heat transfer coefficient in the mixed convection regime, which was found to be significantly larger than those expected assuming purely forced convection based on the inlet flow rate. The inlet Reynolds (Re) number for the tests ranged from 500 to 1300, while the Grashof (Gr) number varied from 1.5 × 10{sup 5} to 3.8 × 10{sup 6} yielding 0.25 < Ri < 4.3. Using results from RBHT test along with the correlation from the FLECHT-SEASET test program for laminar forced convection, a new correlation ​is proposed for mixed convection in a rod bundle. The new correlation accounts for the enhancement of heat transfer relative to laminar forced convection.

Reduction of background noise induced by wind tunnel jet exit vanes

Science.gov (United States)

Martin, R. M.; Brooks, T. F.; Hoad, D. R.

1985-01-01

The NASA-Langley 4 x 7 m wind tunnel develops low frequency flow pulsations at certain velocity ranges during open throat mode operation, affecting the aerodynamics of the flow and degrading the resulting model test data. Triangular vanes attached to the trailing edge of flat steel rails, mounted 10 cm from the inside of the jet exit walls, have been used to reduce this effect; attention is presently given to methods used to reduce the inherent noise generation of the vanes while retaining their pulsation reduction features.

Hybrid lattice Boltzmann finite difference simulation of mixed convection flows in a lid-driven square cavity

Energy Technology Data Exchange (ETDEWEB)

Bettaibi, Soufiene, E-mail: Bettaibisoufiene@gmail.com [UR: Rayonnement Thermique, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Tunis (Tunisia); Kuznik, Frédéric [INSA-Lyon, CETHIL, F-69621 Villeurbanne (France); Université de Lyon, CNRS, UMR5008, F-69622 Villeurbanne (France); Sediki, Ezeddine [UR: Rayonnement Thermique, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Tunis (Tunisia)

2014-06-27

Highlights: • Mixed convection heat transfer in 2D lid-driven cavity is studied numerically. • Hybrid scheme with multiple relaxation time lattice Boltzmann method is used to obtain the velocity field. • Finite difference method is used to compute the temperature. • Effect of both Richardson and Reynolds numbers for mixed convection is studied. - Abstract: Mixed convection heat transfer in two-dimensional lid-driven rectangular cavity filled with air (Pr=0.71) is studied numerically. A hybrid scheme with multiple relaxation time lattice Boltzmann method (MRT-LBM) is used to obtain the velocity field while the temperature field is deduced from energy balance equation by using the finite difference method (FDM). The main objective of this work is to investigate the model effectiveness for mixed convection flow simulation. Results are presented in terms of streamlines, isotherms and Nusselt numbers. Excellent agreement is obtained between our results and previous works. The different comparisons demonstrate the robustness and the accuracy of our proposed approach.

Further development and performance evaluation of the autonomous sailing boat Maribot Vane

OpenAIRE

Dhomé, Ulysse

2018-01-01

This paper describes the ongoing development of Maribot Vane, an autonomous sailing vessel at the Maritime Robotics Laboratory of KTH, the Royal Institute of Technology, Stockholm. There is an ac-celerating need for ocean sensing where autonomous vehicles can play a key role in assisting scientists with environmental monitoring and collecting oceanographic data. The purpose of Maribot Vane is to offer a sus-tainable alternative for these autonomous missions by using wind and an energy efficie...

Erosion estimation of guide vane end clearance in hydraulic turbines with sediment water flow

Science.gov (United States)

Han, Wei; Kang, Jingbo; Wang, Jie; Peng, Guoyi; Li, Lianyuan; Su, Min

2018-04-01

The end surface of guide vane or head cover is one of the most serious parts of sediment erosion for high-head hydraulic turbines. In order to investigate the relationship between erosion depth of wall surface and the characteristic parameter of erosion, an estimative method including a simplified flow model and a modificatory erosion calculative function is proposed in this paper. The flow between the end surfaces of guide vane and head cover is simplified as a clearance flow around a circular cylinder with a backward facing step. Erosion characteristic parameter of csws3 is calculated with the mixture model for multiphase flow and the renormalization group (RNG) k-𝜀 turbulence model under the actual working conditions, based on which, erosion depths of guide vane and head cover end surfaces are estimated with a modification of erosion coefficient K. The estimation results agree well with the actual situation. It is shown that the estimative method is reasonable for erosion prediction of guide vane and can provide a significant reference to determine the optimal maintenance cycle for hydraulic turbine in the future.

Hybrid Zeolitic Imidazolate Frameworks: Controlling Framework Porosity and Functionality by Mixed-Linker Synthesis

KAUST Repository

Thompson, Joshua A.

2012-05-22

Zeolitic imidazolate frameworks (ZIFs) are a subclass of nanoporous metal-organic frameworks (MOFs) that exhibit zeolite-like structural topologies and have interesting molecular recognition properties, such as molecular sieving and gate-opening effects associated with their pore apertures. The synthesis and characterization of hybrid ZIFs with mixed linkers in the framework are described in this work, producing materials with properties distinctly different from the parent frameworks (ZIF-8, ZIF-90, and ZIF-7). NMR spectroscopy is used to assess the relative amounts of the different linkers included in the frameworks, whereas nitrogen physisorption shows the evolution of the effective pore size distribution in materials resulting from the framework hybridization. X-ray diffraction shows these hybrid materials to be crystalline. In the case of ZIF-8-90 hybrids, the cubic space group of the parent frameworks is continuously maintained, whereas in the case of the ZIF-7-8 hybrids there is a transition from a cubic to a rhombohedral space group. Nitrogen physisorption data reveal that the hybrid materials exhibit substantial changes in gate-opening phenomena, either occurring at continuously tunable partial pressures of nitrogen (ZIF-8-90 hybrids) or loss of gate-opening effects to yield more rigid frameworks (ZIF-7-8 hybrids). With this synthetic approach, significant alterations in MOF properties may be realized to suit a desired separation or catalytic process. © 2012 American Chemical Society.

Background noise measurements from jet exit vanes designed to reduced flow pulsations in an open-jet wind tunnel

Science.gov (United States)

Hoad, D. R.; Martin, R. M.

1985-01-01

Many open jet wind tunnels experience pulsations of the flow which are typically characterized by periodic low frequency velocity and pressure variations. One method of reducing these fluctuations is to install vanes around the perimeter of the jet exit to protrude into the flow. Although these vanes were shown to be effective in reducing the fluctuation content, they can also increase the test section background noise level. The results of an experimental acoustic program in the Langley 4- by 7-Meter Tunnel is presented which evaluates the effect on tunnel background noise of such modifications to the jet exit nozzle. Noise levels for the baseline tunnel configuration are compared with those for three jet exit nozzle modifications, including an enhanced noise reduction configuration that minimizes the effect of the vanes on the background noise. Although the noise levels for this modified vane configuration were comparable to baseline tunnel background noise levels in this facility, installation of these modified vanes in an acoustic tunnel may be of concern because the noise levels for the vanes could be well above background noise levels in a quiet facility.

''VaneCAM'' - the third generation of camshaft adjustment systems; ''VaneCAM'' - Nockenwellenversteller der dritten Generation

Energy Technology Data Exchange (ETDEWEB)

Knecht, A. [Hydraulik-Ring GmbH, Nuertingen (Germany). Entwicklung Motorentechnik; Stephan, W. [Hydraulik-Ring GmbH, Nuertingen (Germany); Hannibal, W. [Fachhochschule Suedwestfalen, Iserlohn (Germany). Labor fuer Konstruktion und CAE-Anwendungen

2002-04-01

Continuously variable camphasers are now well established for modern spark-ignition engines in high-volume production. With the latest generation of camshaft adjustment systems using the vane-type actuator principle, it is possible to move rapidly and reliably through a large adjustment angle. The layout of these adjusting systems is very simple. The production costs are low in comparison to the first generation of camphasers using spur/helical gears to vary the valve timing. The new-generation systems are mechatronic, with the function depending on the coordination and tuning of hydraulic actuation and engine electronics. The term 'VaneCAM' is used for the continuously variable systems of this new generation supplied by Hydraulik-Ring in Nuertingen, Germany. (orig.) [German] Stufenlos wirkende Nockenwellenversteller haben sich an modernen Ottomotoren in den letzten Jahren in der Grossserie etabliert. Mit der neuesten Generation von Nockenwellenverstellern, die nach dem Schwenkmotor-Prinzip aufgebaut sind, lassen sich grosse Verdrehwinkel sehr schnell und betriebssicher verstellen. Der Aufbau dieser Versteller ist einfach, und die Herstellkosten sind gering im Vergleich zur ersten Generation von Verstellern. Bei den Systemen der neuen Generation handelt es sich um mechatronische Systeme, deren Funktion von dem Zusammenspiel und der Abstimmung von hydraulischer Ansteuerung und Motorelektronik abhaengt. Mit dem Begriff 'VaneCAM' werden die stufenlos wirkenden Systeme dieser neuen Generation von Hydraulik-Ring aus Nuertingen bezeichnet. (orig.)

Experimental Study of Elements Promoting Mixing in Fuel Elements

International Nuclear Information System (INIS)

Silin, Nicolas; Juanico, Luis; Delmastro, Dario

2003-01-01

In the present work a thermal tracing technique is used to measure the increase of the mixing between subchannels in the presence of different mixing elements.As representative elements a spacer, a spacer with mixing vanes and turbulence promoter buttons were considered.The performance of these elements was evaluated by studying the behavior of a thermal trace in each case.Also the pressure drop for each case is presented.The results present a qualitative and quantitative guide for the application of each one of these appendages in future nuclear elements

Static pressure recovery analysis in the vane island diffuser of a centrifugal pump

Energy Technology Data Exchange (ETDEWEB)

Si, Qiaorui [National Research Center of Pumps, Jiangsu University, Zhenjiang (China); Dupont, Patrick; Bayeul-Laine, Annie-Claude; Dazin, Antoine; Roussette, Olivier; Bois, Gerard [LML, UMR CNRS 8107 Ecole Centrale de Lille, Lille (France)

2016-02-15

The overall performance of a vane-island type diffuser of a centrifugal pump model was obtained by means of directional probe traverses. These measurements were performed in an air model of a real hydraulic pump for five volume flow rates. Directional probe traverses are performed with a classical three-hole probe to cover most of the complete inlet section of the diffuser from hub to shroud and from pressure to suction side. Existing Particle image velocimetry (PIV) measurement results are also used to compare probe measurement results between the inlet and outlet throats of vane island diffuser at mid-span. Some assistance from already existing unsteady calculation, including leakage effects, is used to evaluate the numerical approach capability and to correctly define the mean initial conditions at impeller's outlet section. Pressure recovery and the measured total pressure loss levels inside this particular vane diffuser geometry are then calculated. Detailed analysis of the flow structure at the inlet section of the vane island diffuser is presented to focus on pressure evolution inside the entire diffuser section for different flow rates. The combined effects of incidence angle and blockage distributions along hub to shroud direction are found to play an important role on loss distribution in such a diffuser.

Assessment of guide vane self-excitation stability at small openings in pump flow

International Nuclear Information System (INIS)

Nennemann, B; Sallaberger, M; Henggeler, U; Gentner, C; Parkinson, E

2012-01-01

A parameter study of self-excited pump turbine guide vane instability at small openings using a combined CFD-1DOF approach shows that clear tendencies are difficult to obtain. Two types of boundary conditions can be used in the simulations: prescribed mass flow and prescribed pressure. Simulations with both show results that - for one specific operating condition - are consistent with a self-excited guide vane incident at a prototype pump turbine. However, over a larger range of reduced velocities, the tendencies obtained with the two boundary condition types are not always consistent. Pressure boundary conditions may be the more realistic option. Results then show that with increasing reduced velocity, guide vanes will eventually reach static instability or divergence. This may not be problematic. In contrast, passing through a zone of dynamic instability during operation should and can be avoided.

Test procedure for use of the shear vane in tanks 103-SY, 103-AN, and 103-AW

International Nuclear Information System (INIS)

LeClair, M.D.; Waters, E.

1995-01-01

This is a record copy of a test procedure for application of the full-scale shear vane to underground waste tanks at Hanford. The introduction of the report provides background information on the development and proof-testing of the shear vane, as well as information about its current location. The document was originally prepared in 1988, and the work as shelved temporarily for lack of funds. Activities to utilize the shear vane will be expedited by use of this information

Enlarging the operation range of a centrifugal compressor by cutting vanes based on CFD

International Nuclear Information System (INIS)

Mo, J T; Pan, X H; Gu, C H; Zheng, S Y

2013-01-01

Many centrifugal compressors are liable to insufficient operation range. The purpose of this paper is to enlarge the operation range of a centrifugal compressor used in turbocharger by cutting vanes. Some numerical works have been done based on CFD. The comparison of the calculated and measured results shows good agreement. The overall performance characteristics of the centrifugal compressor with different cutted vanes are observed and analyzed. The performance characteristic curves show that cutting vanes can increase the operation range by more than 50% with the loss of the highest efficiency limited in 1%. The flow fields are also shown in this paper and related explanations about the change of the performance characteristics curves are given. Shock wave is also detected in the simulation, and some related characteristics are summed up

Local hybrid functionals with orbital-free mixing functions and balanced elimination of self-interaction error

International Nuclear Information System (INIS)

Silva, Piotr de; Corminboeuf, Clémence

2015-01-01

The recently introduced density overlap regions indicator (DORI) [P. de Silva and C. Corminboeuf, J. Chem. Theory Comput. 10(9), 3745–3756 (2014)] is a density-dependent scalar field revealing regions of high density overlap between shells, atoms, and molecules. In this work, we exploit its properties to construct local hybrid exchange-correlation functionals aiming at balanced reduction of the self-interaction error. We show that DORI can successfully replace the ratio of the von Weizsäcker and exact positive-definite kinetic energy densities, which is commonly used in mixing functions of local hybrids. Additionally, we introduce several semi-empirical parameters to control the local and global admixture of exact exchange. The most promising of our local hybrids clearly outperforms the underlying semi-local functionals as well as their global hybrids

PURE OR HYBRID? THE DEVELOPMENT OF MIXED DICTIONARY GENRES

Directory of Open Access Journals (Sweden)

Reinhard R. K. Hartmann

2005-11-01

Full Text Available This paper explores 'hybrid' genres of dictionaries and other reference works. Against the tradition of general dictionaries becoming ever more specialised, there has also been a growing trend of mixing two or more 'pure' dictionary types for achieving specific purposes, e.g. the combination of alphabetic and thematic dictionary,general dictionary and technical glossary, dictionary and thesaurus, dictionary and encyclopedia, monolingual and bilingual dictionary, etc. Examples of these various sub-types are discussed (admitting that dictionary research has neglected their study,with the aim of determining overall trends and implications, particularly with regard to the possibility of their further development with the means of information technology.

Improvement of wells turbine performance by means of 3D guide vanes; Sanjigen annai hane ni yoru wells turbine seino no kaizen

Energy Technology Data Exchange (ETDEWEB)

Takao, M.; Kim, T.H. [Saga University, Saga (Japan); Setoguchi, T. [Saga University, Saga (Japan). Faculty of Science and Engineering; Inoue, M. [Kyushu University, Fukuoka (Japan). Faculty of Engineering

2000-02-25

Performance of a Wells turbine was improved by equipping 3D guide vanes before and behind a rotor. For further improvement, 3D guide vanes have been proposed in this paper. The performance of the Wells turbine with 2D and 3D guide vanes have been investigated experimentally by model testing under steady flow conditions. Then, the running and starting characteristics in irregular ocean waves have been obtained by a computer simulation. As a result, it is found that both of the running and starting characteristics of the Wells turbine with 3D guide vanes are superior to those of the turbine with 2D guide vanes. (author)

Experimental investigation of in-cylinder air flow to optimize number of helical guide vanes to enhance DI diesel engine performance using mamey sapote biodiesel

Science.gov (United States)

Kumar, A. Raj; Janardhana Raju, G.; Hemachandra Reddy, K.

2018-03-01

The current research work investigates the influence of helical guide vanes in to the intake runner of a D.I diesel engine operating by the high viscous Mamey Sapote biodiesel to enhance in-cylinder suction air flow features. Helical guide vanes of different number of vanes are produced from 3D printing and placed in the intake manifold to examine the air flow characteristics. Four different helical guide vane devices namely 3, 4, 5 and 6 vanes of the same dimensions are tested in a D.I diesel engine operating with Mamey Sapote biodiesel blend. As per the experimental results of engine performance and emission characteristics, it is found that 5 vanes helical guide vane swirl device exhibited in addition number of increased improvements such as the brake power and bake thermal efficiency by 2.4% and 8.63% respectively and the HC, NOx, Carbon monoxide and, Smoke densities are reduced by 15.62%, 4.23%, 14.27% and 9.6% at peak load operating conditions as collate with normal engine at the same load. Hence this investigation concluded that Helical Guide Vane Devices successfully enhanced the in-cylinder air flow to improve better addition of Mamey Sapote biodiesel with air leading in better performance of the engine than without vanes.

Exergy Analysis of the Revolving Vane Compressed Air Engine

Directory of Open Access Journals (Sweden)

Alison Subiantoro

2016-01-01

Full Text Available Exergy analysis was applied to a revolving vane compressed air engine. The engine had a swept volume of 30 cm3. At the benchmark conditions, the suction pressure was 8 bar, the discharge pressure was 1 bar, and the operating speed was 3,000 rev·min−1. It was found that the engine had a second-law efficiency of 29.6% at the benchmark conditions. The contributors of exergy loss were friction (49%, throttling (38%, heat transfer (12%, and fluid mixing (1%. A parametric study was also conducted. The parameters to be examined were suction reservoir pressure (4 to 12 bar, operating speed (2,400 to 3,600 rev·min−1, and rotational cylinder inertia (0.94 to 2.81 g·mm2. The study found that a higher suction reservoir pressure initially increased the second-law efficiency but then plateaued at about 30%. With a higher operating speed and a higher cylinder inertia, second-law efficiency decreased. As compared to suction pressure and operating speed, cylinder inertia is the most practical and significant to be modified.

The Hybrid Treatment Process for mixed radioactive and hazardous waste treatment

International Nuclear Information System (INIS)

Ross, W.A.; Kindle, C.H.

1992-06-01

This paper describes a new process for treating mixed hazardous and radioactive waste, commonly called mixed waste. The process is called the Hybrid Treatment Process (HTP), so named because it is built on the 20 years of experience with vitrification of wastes in melters, and the 12 years of experience with treatment of wastes by the in situ vitrification (ISV) process. It also uses techniques from several additional technologies. Mixed wastes are being generated by both the US Department of Energy (DOE) and by commercial sources. The wastes are those that contain both a hazardous waste regulated under the US Environmental Protection Agency's (EPA) Resource, Conservation, and Recovery Act (RCRA) regulations and a radioactive waste with source, special nuclear, or byproduct materials. The dual regulation of the wastes increases the complexity of the treatment, handling, and storage of the waste. The DOE is the largest holder and generator of mixed waste. Its mixed wastes are classified as either high-level, transuranic (TRU), or low-level waste (LLW). High-level mixed wastes will be treated in vitrification plants. Transuranic wastes may be disposed of without treatment by obtaining a no-migration variance from the EPA. Lowlevel wastes, however, will require treatment, but treatment systems with sufficient capacity are not yet available to DOE. Various facilities are being proposed for the treatment of low-level waste. The concept described in this paper represents one option for establishing that treatment capacity

Performance and internal flow characteristics of a cross-flow turbine by guide vane angle

International Nuclear Information System (INIS)

Chen, Z M; Choi, Y D

2013-01-01

This study attempts to investigate the performance and internal flow characteristics of a cross-flow turbine by guide vane angle. In order to improve the performance of a cross flow turbine, the paper presents a numerical investigation of the turbine with air supply and discusses the influence of variable guide vane angle on the internal flow. A newly developed air supply from air suction Hole is adopted. To investigate the performance and internal flow of the cross-flow turbine, the CFD software based on the two-phase flow model is utilized. The numerical grids are made in two-dimensional geometry in order to shorten the time of two-phase calculations. Then a series of CFD analysis has been conducted in the range of different guide vane angle. Moreover, local output power is divided at different stages and the effect of air layer in each stage is examined

Frequency conversion through spontaneous degenerate four wave mixing in large mode area hybrid photonic crystal fibers

DEFF Research Database (Denmark)

Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Olausson, Christina Bjarnal Thulin

2014-01-01

Frequency conversion through spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers. Different FWM processes are observed, phasematching between fiber modes of orthogonal polarization, intermodal phasematching across bandgaps, and intramodal...

An analytical model for droplet separation in vane separators and measurements of grade efficiency and pressure drop

International Nuclear Information System (INIS)

Koopman, Hans K.; Köksoy, Çağatay; Ertunç, Özgür; Lienhart, Hermann; Hedwig, Heinz; Delgado, Antonio

2014-01-01

Highlights: • An analytical model for efficiency is extended with additional geometrical features. • A simplified and a novel vane separator design are investigated experimentally. • Experimental results are significantly affected by re-entrainment effects. • Outlet droplet size spectra are accurately predicted by the model. • The improved grade efficiency doubles the pressure drop. - Abstract: This study investigates the predictive power of analytical models for the droplet separation efficiency of vane separators and compares experimental results of two different vane separator geometries. The ability to predict the separation efficiency of vane separators simplifies their design process, especially when analytical research allows the identification of the most important physical and geometrical parameters and can quantify their contribution. In this paper, an extension of a classical analytical model for separation efficiency is proposed that accounts for the contributions provided by straight wall sections. The extension of the analytical model is benchmarked against experiments performed by Leber (2003) on a single stage straight vane separator. The model is in very reasonable agreement with the experimental values. Results from the analytical model are also compared with experiments performed on a vane separator of simplified geometry (VS-1). The experimental separation efficiencies, computed from the measured liquid mass balances, are significantly below the model predictions, which lie arbitrarily close to unity. This difference is attributed to re-entrainment through film detachment from the last stage of the vane separators. After adjustment for re-entrainment effects, by applying a cut-off filter to the outlet droplet size spectra, the experimental and theoretical outlet Sauter mean diameters show very good agreement. A novel vane separator geometry of patented design (VS-2) is also investigated, comparing experimental results with VS-1

Performance Analysis of a Centrifugal Compressor for HFC-134a with aviation of Diffuser Vane Angle

International Nuclear Information System (INIS)

Park, Han Young; Chung, Jin Taek; Shin, You Hwan; Lee, Yoon Pyo; Kim, Kwang Ho; Cho, Yong Hun; Kim, Jong Seong

2007-01-01

Numerical simulation on the two-stage centrifugal compressor with Low Solidity Vaned Diffuser (LSVD) for HFC-134a turbo-chiller was performed using a commercial code. The comparative study with experimental results from other compressor was also investigated to testify the simulation schemes. The numerical analysis was separately simulated for each stage of the compressor and the effect of impeller-diffuser flow interaction was considered. Setting angle of the diffuser vane changed in the range of 15 .deg. and the effects on its variation were discussed in detail including the flow analysis in the passage of the compressor. The vane setting angle obtained from the preliminary design was slightly adjusted to the optimal value by the performance enhancement in terms of pressure recovery and flow characteristics

Adaptive mixed-hybrid and penalty discontinuous Galerkin method for two-phase flow in heterogeneous media

KAUST Repository

Hou, Jiangyong

2016-02-05

In this paper, we present a hybrid method, which consists of a mixed-hybrid finite element method and a penalty discontinuous Galerkin method, for the approximation of a fractional flow formulation of a two-phase flow problem in heterogeneous media with discontinuous capillary pressure. The fractional flow formulation is comprised of a wetting phase pressure equation and a wetting phase saturation equation which are coupled through a total velocity and the saturation affected coefficients. For the wetting phase pressure equation, the continuous mixed-hybrid finite element method space can be utilized due to a fundamental property that the wetting phase pressure is continuous. While it can reduce the computational cost by using less degrees of freedom and avoiding the post-processing of velocity reconstruction, this method can also keep several good properties of the discontinuous Galerkin method, which are important to the fractional flow formulation, such as the local mass balance, continuous normal flux and capability of handling the discontinuous capillary pressure. For the wetting phase saturation equation, the penalty discontinuous Galerkin method is utilized due to its capability of handling the discontinuous jump of the wetting phase saturation. Furthermore, an adaptive algorithm for the hybrid method together with the centroidal Voronoi Delaunay triangulation technique is proposed. Five numerical examples are presented to illustrate the features of proposed numerical method, such as the optimal convergence order, the accurate and efficient velocity approximation, and the applicability to the simulation of water flooding in oil field and the oil-trapping or barrier effect phenomena.

Adaptive mixed-hybrid and penalty discontinuous Galerkin method for two-phase flow in heterogeneous media

KAUST Repository

Hou, Jiangyong; Chen, Jie; Sun, Shuyu; Chen, Zhangxin

2016-01-01

In this paper, we present a hybrid method, which consists of a mixed-hybrid finite element method and a penalty discontinuous Galerkin method, for the approximation of a fractional flow formulation of a two-phase flow problem in heterogeneous media with discontinuous capillary pressure. The fractional flow formulation is comprised of a wetting phase pressure equation and a wetting phase saturation equation which are coupled through a total velocity and the saturation affected coefficients. For the wetting phase pressure equation, the continuous mixed-hybrid finite element method space can be utilized due to a fundamental property that the wetting phase pressure is continuous. While it can reduce the computational cost by using less degrees of freedom and avoiding the post-processing of velocity reconstruction, this method can also keep several good properties of the discontinuous Galerkin method, which are important to the fractional flow formulation, such as the local mass balance, continuous normal flux and capability of handling the discontinuous capillary pressure. For the wetting phase saturation equation, the penalty discontinuous Galerkin method is utilized due to its capability of handling the discontinuous jump of the wetting phase saturation. Furthermore, an adaptive algorithm for the hybrid method together with the centroidal Voronoi Delaunay triangulation technique is proposed. Five numerical examples are presented to illustrate the features of proposed numerical method, such as the optimal convergence order, the accurate and efficient velocity approximation, and the applicability to the simulation of water flooding in oil field and the oil-trapping or barrier effect phenomena.

Mixing of maize and wheat genomic DNA by somatic hybridization in regenerated sterile maize plants.

Science.gov (United States)

Szarka, B.; Göntér, I.; Molnár-Láng, M.; Mórocz, S.; Dudits, D.

2002-07-01

Intergeneric somatic hybridization was performed between albino maize ( Zea mays L.) protoplasts and mesophyll protoplasts of wheat ( Triticum aestivum L.) by polyethylene glycol (PEG) treatments. None of the parental protoplasts were able to produce green plants without fusion. The maize cells regenerated only rudimentary albino plantlets of limited viability, and the wheat mesophyll protoplasts were unable to divide. PEG-mediated fusion treatments resulted in hybrid cells with mixed cytoplasm. Six months after fusion green embryogenic calli were selected as putative hybrids. The first-regenerates were discovered as aborted embryos. Regeneration of intact, green, maize-like plants needed 6 months of further subcultures on hormone-free medium. These plants were sterile, although had both male and female flowers. The cytological analysis of cells from callus tissues and root tips revealed 56 chromosomes, but intact wheat chromosomes were not observed. Using total DNA from hybrid plants, three RAPD primer combinations produced bands resembling the wheat profile. Genomic in situ hybridization (GISH) using total wheat DNA as a probe revealed the presence of wheat DNA islands in the maize chromosomal background. The increased viability and the restored green color were the most-significant new traits as compared to the original maize parent. Other intermediate morphological traits of plants with hybrid origin were not found.

the screw-conveyor vane design for piece-wise construction

African Journals Online (AJOL)

Dr Obe

Summary. One of the long-used methods of conveying granular, Powdery or slurry material is by the screw conveyor. This method of transport is well suited to some at the needs of local processing Industries based on such local produce as millet, maize, cocoa-beans, rice, palm-kernels. The spiral vanes of such conveyors ...

A Three-Dimensional Coupled Internal/External Simulation of a Film-Cooled Turbine Vane

Science.gov (United States)

Heidmann, James D.; Rigby, David L.; Ameri, Ali A.

1999-01-01

A three-dimensional Navier-Stokes simulation has been performed for a realistic film-cooled turbine vane using the LeRC-HT code. The simulation includes the flow regions inside the coolant plena and film cooling holes in addition to the external flow. The vane is the subject of an upcoming NASA Glenn Research Center experiment and has both circular cross-section and shaped film cooling holes. This complex geometry is modeled using a multi-block grid which accurately discretizes the actual vane geometry including shaped holes. The simulation matches operating conditions for the planned experiment and assumes periodicity in the spanwise direction on the scale of one pitch of the film cooling hole pattern. Two computations were performed for different isothermal wall temperatures, allowing independent determination of heat transfer coefficients and film effectiveness values. The results indicate separate localized regions of high heat transfer coefficient values, while the shaped holes provide a reduction in heat flux through both parameters. Hole exit data indicate rather simple skewed profiles for the round holes, but complex profiles for the shaped holes with mass fluxes skewed strongly toward their leading edges.

Measuring Undrained Shear Strength using CPT and Field Vane

DEFF Research Database (Denmark)

Luke, Kirsten

1992-01-01

This paper presents the results of CPT's and Field Vane tests from two small test areas with different soils, Glacial Till and Yoldia Clay. An average of Nk = qt/cv for the Yoldia Clay is 7.7 with a standard deviation of 0.7. The average of Nk for the Glacial Till is 9.7 with a standard deviation...

Mixed Inter Second Order Cone Programming Taking Appropriate Approximation for the Unit Commitment in Hybrid AC-DC Grid

DEFF Research Database (Denmark)

Zhou, Bo; Ai, Xiaomeng; Fang, Jiakun

2017-01-01

With the rapid development and deployment of voltage source converter (VSC) based HVDC, the traditional power system is evolving to the hybrid AC-DC grid. New optimization methods are urgently needed for these hybrid AC-DC power systems. In this paper, mixed-integer second order cone programming...... (MISOCP) for the hybrid AC-DC power systems is proposed. The second order cone (SOC) relaxation is adopted to transform the AC and DC power flow constraints to MISOCP. Several IEEE test systems are used to validate the proposed MISCOP formulation of the optimal power flow (OPF) and unit commitment (UC...

T2-weighted liver MRI using the multiVane technique at 3T: Comparison with conventional T2-weighted MRI

Energy Technology Data Exchange (ETDEWEB)

Kang, Kyung A [Dept. of Radiology, Myongji Hospital, Seonam University College of Medicine, Goyang (Korea, Republic of); Kim, Young Kon; Jeong, Woo Kyoung; Choi, Dong Il; Lee, Won Jae [Dept. of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Eun Ju [Philips Healthcare Korea, Philips, Seoul (Korea, Republic of); Jung, Sin Ho; Baek, Sun Young [Biostatistics and Clinical Epidemiology Center, Samsung Medical Center, Seoul (Korea, Republic of)

2015-10-15

To assess the value of applying MultiVane to liver T2-weighted imaging (T2WI) compared with conventional T2WIs with emphasis on detection of focal liver lesions. Seventy-eight patients (43 men and 35 women) with 86 hepatic lesions and 20 pancreatico-biliary diseases underwent MRI including T2WIs acquired using breath-hold (BH), respiratory-triggered (RT), and MultiVane technique at 3T. Two reviewers evaluated each T2WI with respect to artefacts, organ sharpness, and conspicuity of intrahepatic vessels, hilar duct, and main lesion using five-point scales, and made pairwise comparisons between T2WI sequences for these categories. Diagnostic accuracy (Az) and sensitivity for hepatic lesion detection were evaluated using alternative free-response receiver operating characteristic analysis. MultiVane T2WI was significantly better than BH-T2WI or RT-T2WI for organ sharpness and conspicuity of intrahepatic vessels and main lesion in both separate reviews and pairwise comparisons (p < 0.001). With regard to motion artefacts, MultiVane T2WI or BH-T2WI was better than RT-T2WI (p < 0.001). Conspicuity of hilar duct was better with BH-T2WI than with MultiVane T2WI (p = 0.030) or RT-T2WI (p < 0.001). For detection of 86 hepatic lesions, sensitivity (mean, 97.7%) of MultiVane T2WI was significantly higher than that of BH-T2WI (mean, 89.5%) (p = 0.008) or RT-T2WI (mean, 84.9%) (p = 0.001). Applying the MultiVane technique to T2WI of the liver is a promising approach to improving image quality that results in increased detection of focal liver lesions compared with conventional T2WI.

CFD analysis on mixing effects of spacer grids with different dimples and sizes for advanced fuel assemblies

Energy Technology Data Exchange (ETDEWEB)

Yang, B.W.; Zhang, H.; Han, B.; Zha, Y.D.; Shan, J.Q. [Xi' an Jiaotong Univ. (China). School of Nuclear Science and Technology

2016-07-15

The thermal hydraulic characteristics of a mixing vane grid are largely dependent on the structure of key components, such as strip, spring, dimple, weld nugget, as well as the mixing vane configuration. In this paper, several types of spacer grids with different dimple shapes are modeled under subcooled boiling conditions. Prior to the application of CFD on the dimple shape analysis, the mixing effects of spacer grids were studied. After the dimple shape analysis, the side channel effect is discussed by comparing the simulation results of a 3 x 3 and a 5 x 5 spacer grid. The two phase flow CFD models in this study are validated through simple geometry showing that the calculated void fraction is in good agreement with the experimental data. The dimple comparison result shows that varying dimple structures can result in different temperatures, lateral velocities and void fraction distributions downstream of the spacer grids. Comparison of two sizes of spacer grids demonstrate that the side channel generates different flow distribution pattern in the center channel.

Ultra low injection angle fuel holes in a combustor fuel nozzle

Science.gov (United States)

York, William David

2012-10-23

A fuel nozzle for a combustor includes a mixing passage through which fluid is directed toward a combustion area and a plurality of swirler vanes disposed in the mixing passage. Each swirler vane of the plurality of swirler vanes includes at least one fuel hole through which fuel enters the mixing passage in an injection direction substantially parallel to an outer surface of the plurality of swirler vanes thereby decreasing a flameholding tendency of the fuel nozzle. A method of operating a fuel nozzle for a combustor includes flowing a fluid through a mixing passage past a plurality of swirler vanes and injecting a fuel into the mixing passage in an injection direction substantially parallel to an outer surface of the plurality of swirler vanes.

Performance Enhancement of the In-Line Fan Equipped with the Guiding Vane and the Tail Body

Directory of Open Access Journals (Sweden)

Hung-Cheng Yen

2014-02-01

Full Text Available This integrated numerical and experimental study intends to enhance the performance of an in-line fan with the implement of the guiding vane and the tail body. At first the flow flied associated with the original in-line fan is simulated and analyzed within the framework of CFD code Fluent, in which the finite volume method is applied. Next, the guiding vane is constructed based on the calculated flow characteristics, and attached in the downstream of rotor to smoothen the flow pattern. An appropriate guiding vane with high-performance and low-noise features can be achieved after several design iterations. In addition, the tail body connected to the motor is introduced for further enhancing the fan performance by reducing the sizes of wake and reversed flow behind the hub. Thereafter, to manufacture the mockup for experimental verification, the modified fan with guiding vane is plotted in the CAD/CAM format for mockup fabrication via the rapid-prototype technique. Moreover, a set of relations correlating the performance and noise of this fan prototype are executed inside AMCA test chamber and semianechoic chamber, respectively. Consequently, the feasibility of design scheme and numerical system can be verified according to these experimental results. In summary, this work provides a systematic scheme for designing and analyzing the in-line fan.

Amine–mixed oxide hybrid materials for carbon dioxide adsorption from CO2/H2 mixture

Science.gov (United States)

Ravi, Navin; Aishah Anuar, Siti; Yusuf, Nur Yusra Mt; Isahak, Wan Nor Roslam Wan; Shahbudin Masdar, Mohd

2018-05-01

Bio-hydrogen mainly contains hydrogen and high level of carbon dioxide (CO2). High concentration of CO2 lead to a limitation especially in fuel cell application. In this study, the amine-mixed oxide hybrid materials for CO2 separation from bio-hydrogen model (50% CO2:50% H2) have been studied. Fourier-transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) characterizations showed that the amine–mixed oxide hybrid materials successfully adsorbed CO2 physically with no chemical adsorption evidence. The dry gas of CO2/H2 mixture adsorbed physically on amine–CuO–MgO hybrid material. No carbonates were detected after several times of adsorption, which indicated the good recyclability of adsorbents. The adsorbent system of diethanolamine (DEA)/15% CuO–75% MgO showed the highest CO2 adsorption capacity of 21.2 wt% due to the presence of polar substance on MgO surface, which can adsorb CO2 at ambient condition. The alcohol group of DEA can enhance the CO2 solubility on the adsorbent surface. In the 20% CuO–50% MgO adsorbent system, DEA as amine type showed a high CO2 adsorption of 19.4 wt%. The 10% amine loading system showed that the DEA adsorption system provided high CO2 adsorption. The BET analysis confirmed that a high amine loading contributed to the decrease in CO2 adsorption due to the low surface area of the adsorbent system.

Study and Control of a Radial Vaned Diffuser Stall

Directory of Open Access Journals (Sweden)

Aurélien Marsan

2012-01-01

Full Text Available The aim of the present study is to evaluate the efficiency of a boundary layer suction technique in case of a centrifugal compressor stage in order to extend its stable operating range. First, an analysis of the flow pattern within the radial vaned diffuser is presented. It highlights the stall of the diffuser vanes when reaching a low massflow. A boundary layer separation in the hub-suction side corner grows when decreasing the massflow from the nominal operating point to the surge and finally leads to a massive stall. An aspiration strategy is investigated in order to control the stall. The suction slot is put in the vicinity of the saddle that originates the main separating skin-friction line, identified thanks to the analysis of the skin-friction pattern. Several aspiration massflow rates are tested, and two different modelings of the aspiration are evaluated. Finally, an efficient control is reached with a removal of only 0,1% of the global massflow and leads—from a steady-state calculations point of view—to an increase by 40% of the compressor operating range extent.

The VanE operon in Enterococcus faecalis N00-410 is found on a putative integrative and conjugative element, Tn6202.

Science.gov (United States)

Boyd, D A; Mulvey, M R

2013-02-01

To date no complete genetic structure of acquired DNA harbouring a d-Ala-d-Ser operon in an Enterococcus is known. We wished to characterize the acquired DNA harbouring the vanE operon located in the Enterococcus faecalis N00-410 chromosome. Whole genome sequencing of E. faecalis N00-410 was conducted by massively parallel sequencing. Two sequence contigs harbouring the vanE region were linked by PCR and the acquired DNA harbouring the vanE operon was completely characterized. Excision/integration of the region was determined by PCR and transfer attempted by conjugation. The regions flanking the vanE operon were analysed and a total of 42 open reading frames were identified in a region flanked by inverted terminal and direct repeats (Tn6202). Tn6202 could be excised from the chromosome, circularized and the target site rejoined, but transfer could not be demonstrated. The vanE operon was found on the putative integrative and conjugative element Tn6202 in the E. faecalis N00-410 chromosome. This represents the first characterization of acquired DNA harbouring a D-Ala-D-Ser operon.

Numerical investigation of variable inlet guide vanes with trailing-edge dual slots to decrease the aerodynamic load on centrifugal compressor impeller

Directory of Open Access Journals (Sweden)

Jianchi Xin

2016-03-01

Full Text Available In engineering practice, most centrifugal compressors use variable inlet guide vanes which can provide pre-whirl and control volume flow rates. As the impeller of a centrifugal compressor passes through the wakes created from the guide vanes, the aerodynamic parameters change significantly. The concept of adding dual slots at the trailing-edge of the guide vanes is proposed for reducing the aerodynamic load on the compressor impeller blades. In this article, the steady and unsteady performances of the new guide vanes are analysed under two compressor operating conditions (winter and design conditions. The results show that the average amplitude of the impeller passing frequency at the leading edge has a 13% decrease under the winter condition, especially at the middle and root parts. Moreover, the dual slots structure has no effect on the overall compressor performance.

Zero-gravity Mean Free Surface Curvature of a Confined Liquid in a Radially-Vaned Container

Science.gov (United States)

Chen, Yongkang; Callahan, Michael; Weislogel, Mark

2013-01-01

A variety of increasingly intricate container geometries are under consideration for the passive manipulation of liquids aboard spacecraft where the impact of gravity may be neglected. In this study we examine the mean curvature of a liquid volume confined within a radial array of disconnected vanes of infinite extent. This particular geometry possesses a number of desirable characteristics relevant to waste water treatment aboard spacecraft for life support. It is observed that under certain conditions the slender shape of the free surface approaches an asymptote, which can be predicted analytically using new hybrid boundary conditions proposed herein. This contribution represents possibly the final extension of what has been referred to as the method of de Lazzer et al. (1996). The method enables the integration of the Young-Laplace equation over a domain with its boundaries, including the wetted portion of the solid boundaries, symmetry planes, and circular arcs representing free surfaces at the center plane of the liquid body. Asymptotic solutions at several limits are obtained and the analysis is confirmed with numerical computations.

Numerical study of pressure fluctuations in different guide vanes' opening angle in pump mode of a pump turbine

International Nuclear Information System (INIS)

Sun, Y K; Zuo, Z G; Liu, S H; Wu, Y L; Liu, J T

2012-01-01

A numerical model based on a pumped storage power station was built to develop the numerical simulation, to analyze the pressure fluctuations in a pump turbine in different guide vanes' opening angle. The different guide vanes' opening angles were simulated using the SST k-ω turbulence model and SIMPLEC Pressure-Velocity coupling scheme. The pressure sensor were placed in mainly three positions, they are: bottom ring between runner and the wicket gates, downstream and left side in the draft tube cone below the runner. All the peak to peak values of pressure fluctuation meet signal probability of 97%. The frequency is gained by Fast Fourier Transform. The pressure fluctuations in different positions of the model in pump condition were showed when the guide vanes' opening angels were different. The simulation results confirmed the results gained in model tests. The results show that pressure fluctuations in design opening angle were much lower than those in off design opening angle. The main source of pressure fluctuations between runner and guide vanes is rotor stator interaction. While a lower frequency is the main frequency of the pressure fluctuation in draft tube.

Diaphite, a new type of surface with mixed sp{sup 2}-sp{sup 3} hybridization for adsorption and functionalization

Energy Technology Data Exchange (ETDEWEB)

Radosinski, Lukasz, E-mail: lukasz.radosinski@pwr.edu.pl [Wroclaw University of Science and Technology, Chemistry Department, Group of Bioprocess and Biomedical Engineering, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Formalik, Filip [Wroclaw University of Science and Technology, Chemistry Department, Group of Bioprocess and Biomedical Engineering, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Olejniczak, Adam [Department of Spectroscopy of Excited States, Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, 50-422 Wroclaw (Poland); Radosz, Andrzej [Wroclaw University of Science and Technology, Faculty of Fundamental Problems of Technology, Department of Quantum Technologies, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)

2017-05-15

Highlights: • Recent discoveries show a possibility of photoinduced formation of a structure of mixed sp{sub 2}-sp{sub 3} hybridization out of graphite and graphene–diaphite. • Ab initio and molecular mechanics calculations indicate that the surface exhibits large enhancement of binding energy due to favorable sp{sub 3} like hybridization. • The binding energy varies upon configuration of occupied adsorption sites and the adsorption sites form a regular bed-like matrix. - Abstract: We theoretically study a new carbon phase with mixed sp{sup 2}-sp{sup 3} bond hybridization called diaphite. Using ab initio calculations and the adaptive intermolecular reactive bond order (AIREBO) potential approach, we show that the surface of this structure exhibits enhanced adsorption capabilities. Specifically, using hydrogen as a test adsorbate, we calculate that the chemical binding energy, depending on the configuration of hydrogen atoms, varies from 2.08 to 2.9 eV. Furthermore, the adsorption sites form a regular matrix; thus, we postulate that this new stable carbon phase may be a universal matrix for functionalization.

Suction Side Roughness Effects on Film Cooling Heat Transfer on a Turbine Vane

National Research Council Canada - National Science Library

Rutledge, James

2004-01-01

An experimental study was conducted in a simulated three vane linear cascade to determine the effects of surface roughness and film cooling on the heat transfer coefficient distribution in the region...

Analytical solution for the electrical properties of a radio-frequency quadrupole (RFQ) with simple vanes

International Nuclear Information System (INIS)

Lancaster, H.

1982-01-01

Although the SUPERFISH program is used for calculating the design parameters of an RFQ structure with complex vanes, an analytical solution for electrical properties of an RFQ with simple vanes provides insight into the parametric behavior of these more complicated resonators. The fields in an inclined plane wave guide with proper boundary conditions match those in one quadrant of an RFQ. The principle of duality is used to exploit the solutions to a radial transmission line in solving the field equations. Calculated are the frequency equation, frequency sensitivity factors, electric field, magnetic field, stored energy (U), power dissipation, and quality factor

An Investigation of a Hybrid Mixing Timescale Model for PDF Simulations of Turbulent Premixed Flames

Science.gov (United States)

Zhou, Hua; Kuron, Mike; Ren, Zhuyin; Lu, Tianfeng; Chen, Jacqueline H.

2016-11-01

Transported probability density function (TPDF) method features the generality for all combustion regimes, which is attractive for turbulent combustion simulations. However, the modeling of micromixing due to molecular diffusion is still considered to be a primary challenge for TPDF method, especially in turbulent premixed flames. Recently, a hybrid mixing rate model for TPDF simulations of turbulent premixed flames has been proposed, which recovers the correct mixing rates in the limits of flamelet regime and broken reaction zone regime while at the same time aims to properly account for the transition in between. In this work, this model is employed in TPDF simulations of turbulent premixed methane-air slot burner flames. The model performance is assessed by comparing the results from both direct numerical simulation (DNS) and conventional constant mechanical-to-scalar mixing rate model. This work is Granted by NSFC 51476087 and 91441202.

Investigation of Blade-row Flow Distributions in Axial-flow-compressor Stage Consisting of Guide Vanes and Rotor-blade Row

Science.gov (United States)

Mahoney, John J; Dugan, Paul D; Budinger, Raymond E; Goelzer, H Fred

1950-01-01

A 30-inch tip-diameter axial-flow compressor stage was investigated with and without rotor to determine individual blade-row performance, interblade-row effects, and outer-wall boundary-layer conditions. Velocity gradients at guide-vane outlet without rotor approximated design assumptions, when the measured variation of leaving angle was considered. With rotor in operation, Mach number and rotor-blade effects changed flow distribution leaving guide vanes and invalidated design assumption of radial equilibrium. Rotor-blade performance correlated interpolated two-dimensional results within 2 degrees, although tip stall was indicated in experimental and not two-dimensional results. Boundary-displacement thickness was less than 1.0 and 1.5 percent of passage height after guide vanes and after rotor, respectively, but increased rapidly after rotor when tip stall occurred.

Effect of long time service exposure on microstructure and mechanical properties of gas turbine vanes made of IN939 alloy

International Nuclear Information System (INIS)

Jahangiri, M.R.; Abedini, M.

2014-01-01

Highlights: • Microstructure of service-exposed turbine vanes made of IN939 was investigated. • Mechanical properties of service-exposed alloy were also investigated. • Formation of M 23 C 6 films on GBs and degeneration of MCs are microstructural changes. • Despite its thermodynamic favorability, σ phase is not observed in microstructure. • Microstructural changes lead to a loss in tensile ductility and creep life. - Abstract: In the present study, the effects of long-term service exposure have been investigated on microstructure and mechanical properties of gas turbine vanes made of IN939 superalloy. The major microstructural changes for the investigated service-exposed vanes include the formation of continuous grain boundary carbides and the transformation (degeneration) of MC carbides located at the grain boundaries. The brittle σ phase, which is predicted to be stable on the basis of thermodynamic calculations, is not observed in the microstructure of service-exposed vanes. The microstructural changes during service lead to a loss in room temperature ductility as well as in creep properties of the alloy

Analysis of waves in the plasma guided by a periodical vane-type slow wave structure

International Nuclear Information System (INIS)

Wu, T.J.; Kou, C.S.

2005-01-01

In this study, the dispersion relation has been derived to characterize the propagation of the waves in the plasma guided by a periodical vane-type slow wave structure. The plasma is confined by a quartz plate. Results indicate that there are two different waves in this structure. One is the plasma mode that originates from the plasma surface wave propagating along the interface between the plasma and the quartz plate, and the other is the guide mode that originally travels along the vane-type slow wave structure. In contrast to its original slow wave characteristics, the guide mode becomes a fast wave in the low-frequency portion of the passband, and there exists a cut-off frequency for the guide mode. The vane-type guiding structure has been shown to limit the upper frequency of the passband of the plasma mode, compared with that of the plasma surface wave. In addition, the passband of the plasma mode increases with the plasma density while it becomes narrower for the guide mode. The influences of the parameters of the guiding structure and plasma density on the propagation of waves are also presented

Optical studies of photoactive states in mixed organic-inorganic hybrid perovskites stabilized in polymers

Science.gov (United States)

Kardynal, Beata; Xi, Lifei; Salim, Teddy; Borghardt, Sven; Stoica, Toma; Lam, Yeng Ming

2015-03-01

Mixed organic-inorganic hybrid perovskites MAX-PbY2(X,Y =I, Br,Cl) have been demonstrated as very attractive materials for absorbers of solar cells and active layers of light emitting diodes and optically driven lasers. The bandgap of the perovskites can be tuned by mixing halogen atoms in different ratios. In this presentation we study mixed MAX-PbY2(X,Y =I, Br, Cl) particles synthesized directly in protective polymer matrices as light emitters. Both, time integrated and time resolved photoluminescence have been used to study the materials. So synthesized MAX-PbX2 are very stable when measured at room temperature and in air with radiative recombination of photogenerated carriers as the main decay path. In contrast, MAX-PbY2 with mixed halogen atoms display luminescence from sub-bandgap states which saturate at higher excitation levels. The density of these states depends on the used polymer matrix and increases upon illumination. We further compare the MAX-PbY2 synthesized in polymers and as films and show that these states are inherent to the material rather than its microstructure. This works has been supported by EU NWs4LIGHT grant.

Preferential exclusion of hybrids in mixed pollinations between oilseed rape (Brassica napus) and weedy B. campestris (Brassicaceae)

DEFF Research Database (Denmark)

Hauser, T.P.; Bagger Jørgensen, Rikke; Østergård, Hanne

1997-01-01

amplified polymorphic DNA analysis. Using data on the proportion of fully developed seeds and the proportion of these seeds that were hybrids, a statistical model was constructed to estimate the fitness of conspecific and heterospecific pollen and the survival of conspecific and heterospecific zygotes...... for competition between male gametophytes and/or seeds within pods. To test whether competition influences the success of hybridization, pollen from the two species was mixed in different proportions and applied to stigmas of both species. The resulting seeds were scored for paternity by isozyme and randomly...... to seeds. B. campestris pollen in B. napus styles had a significantly lower fitness than the conspecific pollen, whereas no difference between pollen types was found in B. campestris styles. Hybrid zygotes survived to significantly lower proportions than conspecific zygotes in both species, with the lowest...

An Empirical Model for Vane-Type Vortex Generators in a Navier-Stokes Code

Science.gov (United States)

Dudek, Julianne C.

2005-01-01

An empirical model which simulates the effects of vane-type vortex generators in ducts was incorporated into the Wind-US Navier-Stokes computational fluid dynamics code. The model enables the effects of the vortex generators to be simulated without defining the details of the geometry within the grid, and makes it practical for researchers to evaluate multiple combinations of vortex generator arrangements. The model determines the strength of each vortex based on the generator geometry and the local flow conditions. Validation results are presented for flow in a straight pipe with a counter-rotating vortex generator arrangement, and the results are compared with experimental data and computational simulations using a gridded vane generator. Results are also presented for vortex generator arrays in two S-duct diffusers, along with accompanying experimental data. The effects of grid resolution and turbulence model are also examined.

Welfare Mix and Hybridity. Flexible Adjustments to Changed Environments. Introduction to the Special Issue

DEFF Research Database (Denmark)

Henriksen, Lars Skov; Smith, Steven Rathgeb; Zimmer, Annette

2015-01-01

Present day welfare societies rely on a complex mix of different providers ranging from the state, markets, family, and non-profit organizations to unions, grassroots organizations, and informal networks. At the same time changing welfare discourses have opened up space for new partnerships...... organizations and organizational fields adjust to a new environment that is increasingly dominated by the logic of the market, and how in particular nonprofit organizations, as hybrids by definition, are able to cope with new demands, funding structures, and control mechanisms....

Advanced Instrumentation for Measuring Fluid-Structure Coupling Phenomena in the Guide Vanes Cascade of a Pump-Turbine Scale Model

OpenAIRE

Roth, Steven; Hasmatuchi, Vlad; Botero, Francisco; Farhat, Mohamed; Avellan, François

2010-01-01

In the present study, the fluid-structure coupling is investigated in the guide vanes of a pump-turbine scale model placed in one of the test rigs of the Laboratory for Hydraulic Machines (EPFL) in Lausanne. The paper focuses on the advanced instrumentation used to get reliable and complete fluid-structure coupling results. Semi-conductor strain gages are installed on three guide vanes which are especially weakened to account for stronger fluid-structure coupling phenomena. These are statical...

Degenerate four wave mixing in large mode area hybrid photonic crystal fibers

DEFF Research Database (Denmark)

Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Lægsgaard, Jesper

2013-01-01

Spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers, in which photonic bandgap guidance and index guidance is combined. Calculations show the parametric gain is maximum on the edge of a photonic bandgap, for a large range of pump...... wavelengths. The FWM products are observed on the edges of a transmission band experimentally, in good agreement with the numerical results. Thereby the bandedges can be used to control the spectral positions of FWM products through a proper fiber design. The parametric gain control combined with a large mode...... area fiber design potentially allows for power scaling of light at wavelengths not easily accessible with e.g. rare earth ions....

Characterization of Rotating Detonation Engine Exhaust Through Nozzle Guide Vanes

Science.gov (United States)

2013-03-21

ENY/13-M09 Abstract A Rotating Detonation Engine ( RDE ) has higher thermal efficiencies in comparison to its traditional gas turbine counterparts. Thus...as budgets decrease and fuel costs increase, RDEs have become a research focus for the United States Air Force. An integration assembly for attaching...the first Nozzle Guide Vane (NGV) section from a T63 gas turbine engine to a 6 inch diameter RDE was designed and built for this study. Pressure

Hybrid Iterative Scheme for Triple Hierarchical Variational Inequalities with Mixed Equilibrium, Variational Inclusion, and Minimization Constraints

Directory of Open Access Journals (Sweden)

Lu-Chuan Ceng

2014-01-01

Full Text Available We introduce and analyze a hybrid iterative algorithm by combining Korpelevich's extragradient method, the hybrid steepest-descent method, and the averaged mapping approach to the gradient-projection algorithm. It is proven that, under appropriate assumptions, the proposed algorithm converges strongly to a common element of the fixed point set of finitely many nonexpansive mappings, the solution set of a generalized mixed equilibrium problem (GMEP, the solution set of finitely many variational inclusions, and the solution set of a convex minimization problem (CMP, which is also a unique solution of a triple hierarchical variational inequality (THVI in a real Hilbert space. In addition, we also consider the application of the proposed algorithm to solving a hierarchical variational inequality problem with constraints of the GMEP, the CMP, and finitely many variational inclusions.

An Investigation of a Hybrid Mixing Model for PDF Simulations of Turbulent Premixed Flames

Science.gov (United States)

Zhou, Hua; Li, Shan; Wang, Hu; Ren, Zhuyin

2015-11-01

Predictive simulations of turbulent premixed flames over a wide range of Damköhler numbers in the framework of Probability Density Function (PDF) method still remain challenging due to the deficiency in current micro-mixing models. In this work, a hybrid micro-mixing model, valid in both the flamelet regime and broken reaction zone regime, is proposed. A priori testing of this model is first performed by examining the conditional scalar dissipation rate and conditional scalar diffusion in a 3-D direct numerical simulation dataset of a temporally evolving turbulent slot jet flame of lean premixed H2-air in the thin reaction zone regime. Then, this new model is applied to PDF simulations of the Piloted Premixed Jet Burner (PPJB) flames, which are a set of highly shear turbulent premixed flames and feature strong turbulence-chemistry interaction at high Reynolds and Karlovitz numbers. Supported by NSFC 51476087 and NSFC 91441202.

Aerodynamic forces estimation on jet vanes exposed to supersonic exhaust of a CD Nozzle

International Nuclear Information System (INIS)

Bukhari, S.B.H.; Jehan, I.; Zahir, S.; Khan, M.A.

2003-01-01

A comprehensive study has been made for the estimation of aerodynamic forces on the jet Vane placed in the supersonic exhaust of a Convergent Divergent, CD-Nozzle. Such a system is used to provide the control forces that consist of four orthogonal vanes mounted in the supersonic exhaust of the CD-Nozzles. The flow field parameters for a CD Nozzle were analyzed and validated earlier. In this paper the published experimental and CFD results from RAMPANT Code from Fluent Inc. were used to estimate the axial and normal forces by using PAK-3D, a Computational Fluid Dynamics (CFD) software based on Navier-Stokes Equations solver. Results got verified quantitatively with a maximum error of 8% between PAK-3D and experiment, while 4% between PAK-3D and a CFD code, RAMPANT for the axial force. (author)

Analysis of swirl recovery vanes for increased propulsive efficiency in tractor propeller aircraft

NARCIS (Netherlands)

Veldhuis, L.L.M.; Stokkermans, T.C.A.; Sinnige, T.; Eitelberg, G.

2016-01-01

In this paper we address a preliminary assessment of the performance effects of swirl recovery vanes (SRVs) in a installed and uninstalled tractor propeller arrangement. A numerical analysis was performed on a propeller and a propeller-wing configuration after the SRVs were optimized first in a

Automatic efficiency optimization of an axial compressor with adjustable inlet guide vanes

Science.gov (United States)

Li, Jichao; Lin, Feng; Nie, Chaoqun; Chen, Jingyi

2012-04-01

The inlet attack angle of rotor blade reasonably can be adjusted with the change of the stagger angle of inlet guide vane (IGV); so the efficiency of each condition will be affected. For the purpose to improve the efficiency, the DSP (Digital Signal Processor) controller is designed to adjust the stagger angle of IGV automatically in order to optimize the efficiency at any operating condition. The A/D signal collection includes inlet static pressure, outlet static pressure, outlet total pressure, rotor speed and torque signal, the efficiency can be calculated in the DSP, and the angle signal for the stepping motor which control the IGV will be sent out from the D/A. Experimental investigations are performed in a three-stage, low-speed axial compressor with variable inlet guide vanes. It is demonstrated that the DSP designed can well adjust the stagger angle of IGV online, the efficiency under different conditions can be optimized. This establishment of DSP online adjustment scheme may provide a practical solution for improving performance of multi-stage axial flow compressor when its operating condition is varied.

Study on transient hydrodynamic performance and cavitation characteristic of high-speed mixed-flow pump

International Nuclear Information System (INIS)

Chen, T; Liu, Y L; Sun, Y B; Wang, L Q; Wu, D Z

2013-01-01

In order to analyse the hydrodynamic performance and cavitation characteristic of a high-speed mixed-flow pump during transient operations, experimental studies were carried out. The transient hydrodynamic performance and cavitation characteristics of the mixed-flow pump with guide vane during start-up operation processes were tested on the pump performance test-bed. Performance tests of the pump were carried out under various inlet pressures and speed-changing operations. The real-time instantaneous external characteristics such as rotational speed, hydraulic head, flow rate, suction pressure and discharge pressure of the pump were measured. Based on the experimental results, the effect of fluid acceleration on the hydrodynamic performances and cavitation characteristics of the mixed-flow pump were analysed and evaluated

Methodology of Computer-Aided Design of Variable Guide Vanes of Aircraft Engines

Science.gov (United States)

Falaleev, Sergei V.; Melentjev, Vladimir S.; Gvozdev, Alexander S.

2016-01-01

The paper presents a methodology which helps to avoid a great amount of costly experimental research. This methodology includes thermo-gas dynamic design of an engine and its mounts, the profiling of compressor flow path and cascade design of guide vanes. Employing a method elaborated by Howell, we provide a theoretical solution to the task of…

Sequential cooling insert for turbine stator vane

Science.gov (United States)

Jones, Russel B

2017-04-04

A sequential flow cooling insert for a turbine stator vane of a small gas turbine engine, where the impingement cooling insert is formed as a single piece from a metal additive manufacturing process such as 3D metal printing, and where the insert includes a plurality of rows of radial extending impingement cooling air holes alternating with rows of radial extending return air holes on a pressure side wall, and where the insert includes a plurality of rows of chordwise extending second impingement cooling air holes on a suction side wall. The insert includes alternating rows of radial extending cooling air supply channels and return air channels that form a series of impingement cooling on the pressure side followed by the suction side of the insert.

Gas turbine structural mounting arrangement between combustion gas duct annular chamber and turbine vane carrier

Science.gov (United States)

Wiebe, David J.; Charron, Richard C.; Morrison, Jay A.

2016-10-18

A gas turbine engine ducting arrangement (10), including: an annular chamber (14) configured to receive a plurality of discrete flows of combustion gases originating in respective can combustors and to deliver the discrete flows to a turbine inlet annulus, wherein the annular chamber includes an inner diameter (52) and an outer diameter (60); an outer diameter mounting arrangement (34) configured to permit relative radial movement and to prevent relative axial and circumferential movement between the outer diameter and a turbine vane carrier (20); and an inner diameter mounting arrangement (36) including a bracket (64) secured to the turbine vane carrier, wherein the bracket is configured to permit the inner diameter to move radially with the outer diameter and prevent axial deflection of the inner diameter with respect to the outer diameter.

Magnesium Aminoclay-Fe3O4 (MgAC-Fe3O4 Hybrid Composites for Harvesting of Mixed Microalgae

Directory of Open Access Journals (Sweden)

Bohwa Kim

2018-05-01

Full Text Available In this paper, we describe the synthesis of magnesium aminoclay-iron oxide (MgAC-Fe3O4 hybrid composites for microalgae-harvesting application. MgAC-templated Fe3O4 nanoparticles (NPs were synthesized in different ratios of MgAC and Fe3O4 NPs. The uniform distribution of Fe3O4 NPs in the MgAC matrix was confirmed by transmission electron microscopy (TEM. According to obtained X-ray diffraction (XRD patterns, increased MgAC loading leads to decreased intensity of the composites’ (311 plane of Fe3O4 NPs. For harvesting of Chlorella sp. KR-1, Scenedesmus obliquus and mixed microalgae (Chlorella sp. KR-1/ Scenedesmus obliquus, the optimal pH was 4.0. At higher pHs, the microalgae-harvesting efficiencies fell. Sample #1, which had the highest MgAC concentration, showed the most stability: the harvesting efficiencies for Chlorella sp. KR-1, Scenedesmus obliquus, and mixed microalgae were reduced only to ~50% at pH = 10.0. The electrostatic interaction between MgAC and the Fe3O4 NPs in the hybrid samples by microalgae, as confirmed by zeta potential measurements, were attributed to the harvesting mechanisms. Moreover, the zeta potentials of the MgAC-Fe3O4 hybrid composites were reduced as pH was increased, thus diminishing the microalgae-harvesting efficiencies.

Novel investigation of the different Omni-direction-guide-vane angles effects on the urban vertical axis wind turbine output power via three-dimensional numerical simulation

International Nuclear Information System (INIS)

Shahizare, B.; Nik-Ghazali, N.; Chong, W.T.; Tabatabaeikia, S.; Izadyar, Nima; Esmaeilzadeh, Alireza

2016-01-01

Highlights: • Investigation of the Omni-direction-guide-vane impacts on the VAWT performance. • Obtain the best position of the guide vane angles in order to achieve the maximum performance. • Validation of the 3D computational fluid dynamics with experimental data. • Acquire the optimal Omni-direction-guide-vane based on numerical simulation results. - Abstract: The aim of this study is to present the effects of different Omni-direction-guide-vane (ODGV) angles on the performance of the vertical axis wind turbine (VAWT). For this purpose, five different straight-bladed VAWTs have been simulated via three-dimensional (3D) computational fluid dynamics (CFD). Hence, the VAWT without ODGV covering, were simulated and validated via CFD and experimental fluid dynamics (EFD) data, respectively in the first step. Indeed, grid and time step independency test as well as the effect of domain size, have been conducted and a suitable agreement was found based on comparison of the CFD and EFD results. In the next step, the VAWT was shrouded by ODGV cover and the whole system was simulated for 52 angles of the ODGV in four different tip speed ratios (TSR), to investigate the impact of guide vanes angles on the VAWT performance. Results of this study indicated that output power of the VAWT with α = 20° and β = 55° ODGV guide vanes, was improved 40.9%, 36.5%, 35.3% and 33.2%, respectively in four different TSR including 0.745, 1.091, 1.901 and 2.53.

3D shape optimization of fan vanes for multiple operating regimes subject to efficiency and noise-related excellence criteria and constraints

Directory of Open Access Journals (Sweden)

Ivo Marinić-Kragić

2016-01-01

Full Text Available Fully generic 3D shapes of centrifugal roof fan vanes are explored based on a custom-developed numerical workflow with the ability to vary the vane 3D shape by manipulating the control points of parametric surfaces and change the number of vanes and rotation speed. An excellence formulation is based on design flow efficiency, multi-regime operational conditions and noise criteria for various cases, including multi-objective optimization. Multiple cases of optimization demonstrate the suitability of customized and individualized fan designs for specific working environments according to the selected excellence criteria. Noise analysis is considered as an additional decision-making tool for cases where multiple solutions of equal efficiency are generated and as an additional criteria for multi-objective optimization. The 3D vane shape enables further gains in efficiency compared to 2D shape optimization, while multi-objective optimization with noise as an additional criterion shows potential to greatly reduce the roof fan noise with only small losses in efficiency. The developed workflow which comprises (i a 3D parametric shape modeler, (ii an evolutionary optimizer and (iii a computational fluid dynamics (CFD simulator can be viewed as an integral tool for optimizing the designs of roof fans under custom conditions.

Effects of inter-fullerene π-band mixings in the photoexcitation of hybrid plasmons in the C60@C240 molecule

Science.gov (United States)

de, Rume; Madjet, Mohamed; Chakraborty, Himadri

2013-05-01

We perform a detailed study of the ground state electronic structure of a two-layer fullerene onion molecule C60@C240. Calculations are carried out in a quantum mechanical framework of local density approximation (LDA) where the onion's ion-core of sixty C4+ ions from C60 and two hundred and forty of those from C240 is smeared into a classical jellium distribution. Significant inter-fullerene mixing between the bands of single-node radial symmetry, the π-bands, is found. We then compute the photoionization from all the levels of the system using a time-dependent version of LDA at photon energies where the ionization is dominated by the inter-layer hybridization of collective plasmon resonances. It is determined, by comparing the isolated fullerene cross sections with the cross section of the onion system for both π and σ (having nodeless radial waves) symmetry, that the π-band mixing is predominantly responsible for the production of plasmon hybrids. Supported by NSF and DOE.

Influence of the Applied Working Fluid and the Arrangement of the Steering Edges on Multi-Vane Expander Performance in Micro ORC System

Directory of Open Access Journals (Sweden)

Józef Rak

2018-04-01

Full Text Available Micro-power domestic organic Rankine cycle (ORC systems are nowadays of great interest. These systems are considered for combined heat and power (CHP generation in domestic and distributed applications. The main issues of ORC systems design is selection of the expander and the working fluid. Thanks to their positive features, multi-vane expanders are especially promising for application in micro-power ORC systems. These expanders are very simple in design, small in dimensions, inexpensive and feature low gas flow capacity and expansion ratio. The application of multi-vane expanders in ORC systems is innovative and currently limited to prototype applications. However, a literature review indicates the growing interest in these machines and the potential for practical implementation. For this reason, it is necessary to conduct detailed studies on the multi-vane expanders operation in ORC systems. In this paper the results of experimental and numerical investigations on the influence of the applied working fluid and the arrangement of the steering edges on multi-vane expander performance in micro ORC system are reported. The experiments were performed using the specially designed lab test-stand, i.e. the domestic ORC system. Numerical simulations were proceeded in ANSYS CFX software (ANSYS, Inc., Canonsburg, PA, USA and were focused on determining the expander performance under various flow conditions of different working fluids. Detailed numerical analysis of the arrangement of the machine steering edges showed existence of optimal mutual position of the inlet and outlet port for which the multi-vane expander achieves maximum internal work and internal efficiency.

Hybrid determination of mixed-mode stress intensity factors on discontinuous finite-width plate by finite element and photoelasticity

International Nuclear Information System (INIS)

Baek, Tae Hyun; Chen, Lei; Hong, Dong Pyo

2011-01-01

For isotropic material structure, the stress in the vicinity of crack tip is generally much higher than the stress far away from it. This phenomenon usually leads to stress concentration and fracture of structure. Previous researches and studies show that the stress intensity factor is one of most important parameter for crack growth and propagation. This paper provides a convenient numerical method, which is called hybrid photoelasticity method, to accurately determine the stress field distribution in the vicinity of crack tip and mixed-mode stress intensity factors. The model was simulated by finite element method and isochromatic data along straight lines far away from the crack tip were calculated. By using the isochromatic data obtained from finite element method and a conformal mapping procedure, stress components and photoelastic fringes in the hybrid region were calculated. To easily compare calculated photoelastic fringes with experiment results, the fringe patterns were reconstructed, doubled and sharpened. Good agreement shows that the method presented in this paper is reliable and convenient. This method can then directly be applied to obtain mixed mode stress intensity factors from the experimentally measured isochromatic data along the straight lines

The impact of inlet angle and outlet angle of guide vane on pump in reversal based hydraulic turbine performance

International Nuclear Information System (INIS)

Shi, F X; Yang, J H; Wang, X H; Zhang, R H; Li, C E

2012-01-01

In this paper, in order to research the impact of inlet angle and outlet angle of guide vane on hydraulic turbine performance, a centrifugal pump in reversal is adopted as turbine. A numerical simulation method is adopted for researching outer performance and flow field of turbine. The results show: inlet angle has a crucial role to turbine, to the same flow, there is a noticeable decline for the efficiency and head of turbine with the inlet angle increases. At the best efficiency point(EFP),to a same inlet angle, when the inlet angle greater than inlet angle, velocity circulation in guide vane outlet decreases, which lead the efficiency of turbine to reduce, Contrarily, the efficiency rises. With the increase of inlet angle and outlet angle, the EFP moves to the big flow area and the uniformity of pressure distribution becomes worse. The paper indicates that the inlet angle and outlet angle have great impact on the turbine performance, and the best combination exists for the inlet angle and outlet angle of the guide vane.

Multi and mixed 3D-printing of graphene-hydroxyapatite hybrid materials for complex tissue engineering.

Science.gov (United States)

Jakus, Adam E; Shah, Ramille N

2017-01-01

With the emergence of three-dimensional (3D)-printing (3DP) as a vital tool in tissue engineering and medicine, there is an ever growing need to develop new biomaterials that can be 3D-printed and also emulate the compositional, structural, and functional complexities of human tissues and organs. In this work, we probe the 3D-printable biomaterials spectrum by combining two recently established functional 3D-printable particle-laden biomaterial inks: one that contains hydroxyapatite microspheres (hyperelastic bone, HB) and another that contains graphene nanoflakes (3D-graphene, 3DG). We demonstrate that not only can these distinct, osteogenic, and neurogenic inks be co-3D-printed to create complex, multimaterial constructs, but that composite inks of HB and 3DG can also be synthesized. Specifically, the printability, microstructural, mechanical, electrical, and biological properties of a hybrid material comprised of 1:1 HA:graphene by volume is investigated. The resulting HB-3DG hybrid exhibits mixed characteristics of the two distinct systems, while maintaining 3D-printability, electrical conductivity, and flexibility. In vitro assessment of HB-3DG using mesenchymal stem cells demonstrates the hybrid material supports cell viability and proliferation, as well as significantly upregulates both osteogenic and neurogenic gene expression over 14 days. This work ultimately demonstrates a significant step forward towards being able to 3D-print graded, multicompositional, and multifunctional constructs from hybrid inks for complex composite tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 274-283, 2017. © 2016 Wiley Periodicals, Inc.

Hydraulic analysis of river training cross-vanes as part of post-restoration monitoring

Directory of Open Access Journals (Sweden)

T. A. Endreny

2011-07-01

Full Text Available River restoration design methods are incrementally improved by studying and learning from monitoring data in previous projects. In this paper we report post-restoration monitoring data and simulation analysis for a Natural Channel Design (NCD restoration project along 1600 m of the Batavia Kill (14 km² watershed in the Catskill Mountains, NY. The restoration project was completed in 2002 with goals to reduce bank erosion and determine the efficacy of NCD approaches for restoring headwater streams in the Catskill Mountains, NY. The NCD approach used a reference-reach to determine channel form, empirical relations between the project site and reference site bankfull dimensions to size channel geometry, and hydraulic and sediment computations based on a bankfull (1.3 yr return interval discharge to test channel capacity and sediment stability. The NCD project included 12 cross-vanes and 48 j-hook vanes as river training structures along 19 meander bends to protect against bank erosion and maintain scour pools for fish habitat. Monitoring data collected from 2002 to 2004 were used to identify aggradation of pools in meander bends and below some structures. Aggradation in pools was attributed to the meandering riffle-pool channel trending toward step-pool morphology and cross-vane arms not concentrating flow in the center of the channel. The aggradation subsequently caused flow splitting and 4 partial point bar avulsions during a spring 2005 flood with a 25-yr return interval. Processing the pre-flood monitoring data with hydraulic analysis software provided clues the reach was unstable and preventative maintenance was needed. River restoration and monitoring teams should be trained in robust hydraulic analytical methods that help them extend project restoration goals and structure stability.

Thermal modelling of a dry revolving vane compressor

Science.gov (United States)

Ooi, K. T.; Aw, K. T.

2017-08-01

The lubricant used in compressors serves to lubricate, to seal the gaps to reduce internal leakage and to a certain extent, to cool. However, a lubricant free compressor is attractive if lubricants become a source of contaminant, or in areas where the compressor needs be placed under any orientation, such as those in military or portable computing. In this paper, a thermal model for a dry revolving vane compressor is presented. This thermal model sets out to predict the steady-state operating temperatures of the compressor components. The lumped thermal conductance method was employed. The results of the components temperature will be presented and discussed. A high potential for overheating is observed at the shaft bearings.

Effect of turbulence intensity on cross-injection film cooling at a stepped or smooth endwall of a gas turbine vane passage.

Science.gov (United States)

Wu, Pey-Shey; Tsai, Shen-Ta; Jhuo, Yue-Hua

2014-01-01

This study is concerned with a film cooling technique applicable to the protection of the endwalls of a gas turbine vane. In the experiments, cross-injection coolant flow from two-row, paired, inclined holes with nonintersecting centerlines was utilized. The test model is a scaled two-half vane. The levels of turbulence intensity used in the experiments are T.I. = 1.8%, 7%, and 12%. Other parameters considered in the film cooling experiments include three inlet Reynolds numbers (9.20 × 10(4), 1.24 × 10(5), and 1.50 × 10(5)), three blowing ratios (0.5, 1.0, and 2.0), and three endwall conditions (smooth endwall and stepped endwall with forward-facing or backward-facing step). Thermochromic liquid crystal (TLC) technique with steady-state heat transfer experiments was used to obtain the whole-field film cooling effectiveness. Results show that, at low turbulence intensity, increasing Reynolds number decreases the effectiveness in most of the vane passage. There is no monotonic trend of influence by Reynolds number at high turbulence intensity. The effect of blowing ratio on the effectiveness has opposite trends at low and high turbulence levels. Increasing turbulent intensity decreases the effectiveness, especially near the inlet of the vane passage. With a stepped endwall, turbulence intensity has only mild effect on the film cooling effectiveness.

Effect of Turbulence Intensity on Cross-Injection Film Cooling at a Stepped or Smooth Endwall of a Gas Turbine Vane Passage

Directory of Open Access Journals (Sweden)

Pey-Shey Wu

2014-01-01

Full Text Available This study is concerned with a film cooling technique applicable to the protection of the endwalls of a gas turbine vane. In the experiments, cross-injection coolant flow from two-row, paired, inclined holes with nonintersecting centerlines was utilized. The test model is a scaled two-half vane. The levels of turbulence intensity used in the experiments are T.I.=1.8%, 7%, and 12%. Other parameters considered in the film cooling experiments include three inlet Reynolds numbers (9.20×104 , 1.24×105, and  1.50×105, three blowing ratios (0.5, 1.0, and 2.0, and three endwall conditions (smooth endwall and stepped endwall with forward-facing or backward-facing step. Thermochromic liquid crystal (TLC technique with steady-state heat transfer experiments was used to obtain the whole-field film cooling effectiveness. Results show that, at low turbulence intensity, increasing Reynolds number decreases the effectiveness in most of the vane passage. There is no monotonic trend of influence by Reynolds number at high turbulence intensity. The effect of blowing ratio on the effectiveness has opposite trends at low and high turbulence levels. Increasing turbulent intensity decreases the effectiveness, especially near the inlet of the vane passage. With a stepped endwall, turbulence intensity has only mild effect on the film cooling effectiveness.

Enhancing sediment distribution at the vicinity of power plant intakes using double rows of vanes and groins (Case study: New tebbin power plant

Directory of Open Access Journals (Sweden)

Sayed Mahgoub

2013-12-01

The study results showed that, in case of vanes absence, sediments with rates 1–2 m3/week were stuck within the sediment trap under the winter conditions. Also, the results indicated that the submerged vanes play an important role in preventing the sediment intrusion. Also, it was clear that using groins might lead to enhancing the sediment distribution at the intake vicinity.

Design optimization of single mixed refrigerant LNG process using a hybrid modified coordinate descent algorithm

Science.gov (United States)

Qyyum, Muhammad Abdul; Long, Nguyen Van Duc; Minh, Le Quang; Lee, Moonyong

2018-01-01

Design optimization of the single mixed refrigerant (SMR) natural gas liquefaction (LNG) process involves highly non-linear interactions between decision variables, constraints, and the objective function. These non-linear interactions lead to an irreversibility, which deteriorates the energy efficiency of the LNG process. In this study, a simple and highly efficient hybrid modified coordinate descent (HMCD) algorithm was proposed to cope with the optimization of the natural gas liquefaction process. The single mixed refrigerant process was modeled in Aspen Hysys® and then connected to a Microsoft Visual Studio environment. The proposed optimization algorithm provided an improved result compared to the other existing methodologies to find the optimal condition of the complex mixed refrigerant natural gas liquefaction process. By applying the proposed optimization algorithm, the SMR process can be designed with the 0.2555 kW specific compression power which is equivalent to 44.3% energy saving as compared to the base case. Furthermore, in terms of coefficient of performance (COP), it can be enhanced up to 34.7% as compared to the base case. The proposed optimization algorithm provides a deep understanding of the optimization of the liquefaction process in both technical and numerical perspectives. In addition, the HMCD algorithm can be employed to any mixed refrigerant based liquefaction process in the natural gas industry.

Numerical investigation of the variable nozzle effect on the mixed flow turbine performance characteristics

Science.gov (United States)

Meziri, B.; Hamel, M.; Hireche, O.; Hamidou, K.

2016-09-01

There are various matching ways between turbocharger and engine, the variable nozzle turbine is the most significant method. The turbine design must be economic with high efficiency and large capacity over a wide range of operational conditions. These design intents are used in order to decrease thermal load and improve thermal efficiency of the engine. This paper presents an original design method of a variable nozzle vane for mixed flow turbines developed from previous experimental and numerical studies. The new device is evaluated with a numerical simulation over a wide range of rotational speeds, pressure ratios, and different vane angles. The compressible turbulent steady flow is solved using the ANSYS CFX software. The numerical results agree well with experimental data in the nozzleless configuration. In the variable nozzle case, the results show that the turbine performance characteristics are well accepted in different open positions and improved significantly in low speed regime and at low pressure ratio.

Value-added utilisation of recycled concrete in hot-mix asphalt.

Science.gov (United States)

Wong, Yiik Diew; Sun, Darren Delai; Lai, Dickson

2007-01-01

The feasibility of partial substitution of granite aggregate in hot-mix asphalt (HMA) with waste concrete aggregate was investigated. Three hybrid HMA mixes incorporating substitutions of granite fillers/fines with 6%, 45% untreated, and 45% heat-treated concrete were evaluated by the Marshall mix design method; the optimum binder contents were found to be 5.3%, 6.5% and 7.0% of grade Pen 60/70 bitumen, respectively. All three hybrid mixes satisfied the Marshall criteria of the Singapore Land Transport Authority (LTA) W3B wearing course specification. The hybrid mix with 6% concrete fillers gave comparable resilient modulus and creep resistance as the conventional W3B mix, while hybrid mixes with higher concrete substitutions achieved better performance. X-ray diffraction (XRD) showed the distinct presence of free lime in the heat-treated concrete, while the scanning electron microscope (SEM) provided an in-depth perspective of the concrete grains in the HMA matrix. The results suggest feasible use of waste concrete as partial aggregate substitution in HMA.

Study and modeling of fluctuating fluid forces exerted on fuel rods in pressurized water reactors

International Nuclear Information System (INIS)

Bhattacharjee, Saptarshi

2016-01-01

Flow-induced vibrations in a pressurized water reactor (PWR) core can cause fretting wear in the fuel rods. Due to friction, wear occurs at the contact locations between the spacer grid and the fuel rod. This could compromise the first safety barrier of the nuclear reactor by damaging the fuel rod cladding. In order to ensure the integrity of the cladding, it is necessary to know the random fluctuating forces acting on the rods. However, the spectra for these fluid forces are not well known. The goal of this PhD thesis was to use simple geometrical elements to check the reproducibility of realistic pressurized water reactor spacer grids. As a first step, large eddy simulations were performed on a concentric annular pipe for different mesh refinements using the CFD code Trio CFD (previously Trio U) developed by CEA. A mesh sensitivity study was performed to obtain an acceptable mesh for reproducing standard literature results. This information on mesh resolution was used when carrying out simulations using various geometric obstacles inside the pipe, namely, mixing vanes, circular spacer grid and a combination of square spacer grid with mixing vanes. The last of the three configurations is the closest to a realistic PWR fuel assembly. Structured mesh was generated for the annular pipe case and circular grid case. An innovative hybrid mesh was used for the two remaining cases of the mixing vanes and the square grid: keeping unstructured mesh around the obstacles and structured mesh in the rest of the domain. The inner wall of the domain was representative of the fuel rod cladding. Both hydraulic and wall pressure characteristics were analyzed for each case. The results for the square grid case were found to be an approximate combination of the mixing vane case and circular grid case. Simulation results were compared with experiments performed at CEA Cadarache. Some preliminary comparisons were also made with classical semi-empirical models. (author) [fr

Day ahead price forecasting of electricity markets by a mixed data model and hybrid forecast method

International Nuclear Information System (INIS)

Amjady, Nima; Keynia, Farshid

2008-01-01

In a competitive electricity market, forecast of energy prices is a key information for the market participants. However, price signal usually has a complex behavior due to its nonlinearity, nonstationarity, and time variancy. In spite of all performed researches on this area in the recent years, there is still an essential need for more accurate and robust price forecast methods. In this paper, a combination of wavelet transform (WT) and a hybrid forecast method is proposed for this purpose. The hybrid method is composed of cascaded forecasters where each forecaster consists of a neural network (NN) and an evolutionary algorithms (EA). Both time domain and wavelet domain features are considered in a mixed data model for price forecast, in which the candidate input variables are refined by a feature selection technique. The adjustable parameters of the whole method are fine-tuned by a cross-validation technique. The proposed method is examined on PJM electricity market and compared with some of the most recent price forecast methods. (author)

Loss model for off-design performance analysis of radial turbines with pivoting-vane, variable-area stators

Science.gov (United States)

Meitner, P. L.; Glassman, A. J.

1980-01-01

An off-design performance loss model for a radial turbine with pivoting, variable-area stators is developed through a combination of analytical modeling and experimental data analysis. A viscous loss model is used for the variation in stator loss with setting angle, and stator vane end-clearance leakage effects are predicted by a clearance flow model. The variation of rotor loss coefficient with stator setting angle is obtained by means of an analytical matching of experimental data for a rotor that was tested with six stators, having throat areas from 20 to 144% of the design area. An incidence loss model is selected to obtain best agreement with experimental data. The stator vane end-clearance leakage model predicts increasing mass flow and decreasing efficiency as a result of end-clearances, with changes becoming significantly larger with decreasing stator area.

Flow characteristics of guide vane of diffuser pump by PIV measurement

International Nuclear Information System (INIS)

Kim, J. H.; Lee, Young Ho; Choi, J. W.; Kim, M. Y.; Lee, H.

2000-01-01

The present experimental study is focused on the application of multi-point simultaneous measurement by PIV(Particle Image Velocimetry) to guide vane region within a diffuser pump. Various different kinds of clearance were selected as experimental conditions. Optimized cross correlation identification to obtain velocity vectors was implemented with direct calculation of correlation coefficients. Fine optical setup important in PIV performance is arranged for the accurate PIV measurement of high-speed complex flow. Various flow patterns are represented quantitatively at the stator passages

Numerical Investigations of Unsteady Flow in a Centrifugal Pump with a Vaned Diffuser

Directory of Open Access Journals (Sweden)

Olivier Petit

2013-01-01

Full Text Available Computational fluid dynamics (CFD analyses were made to study the unsteady three-dimensional turbulence in the ERCOFTAC centrifugal pump test case. The simulations were carried out using the OpenFOAM Open Source CFD software. The test case consists of an unshrouded centrifugal impeller with seven blades and a radial vaned diffuser with 12 vanes. A large number of measurements are available in the radial gap between the impeller and the diffuse, making this case ideal for validating numerical methods. Results of steady and unsteady calculations of the flow in the pump are compared with the experimental ones, and four different turbulent models are analyzed. The steady simulation uses the frozen rotor concept, while the unsteady simulation uses a fully resolved sliding grid approach. The comparisons show that the unsteady numerical results accurately predict the unsteadiness of the flow, demonstrating the validity and applicability of that methodology for unsteady incompressible turbomachinery flow computations. The steady approach is less accurate, with an unphysical advection of the impeller wakes, but accurate enough for a crude approximation. The different turbulence models predict the flow at the same level of accuracy, with slightly different results.

MATHEMATICAL MODEL FOR THE STUDY AND DESIGN OF A ROTARY-VANE GAS REFRIGERATION MACHINE

Directory of Open Access Journals (Sweden)

V. V. Trandafilov

2016-08-01

Full Text Available This paper presents a mathematical model of calculating the main parameters the operating cycle, rotary-vane gas refrigerating machine that affect installation, machine control and working processes occurring in it at the specified criteria. A procedure and a graphical method for the rotary-vane gas refrigerating machine (RVGRM are proposed. A parametric study of the main geometric variables and temperature variables on the thermal behavior of the system is analyzed. The model considers polytrope index for the compression and expansion in the chamber. Graphs of the pressure and temperature in the chamber of the angle of rotation of the output shaft are received. The possibility of inclusion in the cycle regenerative heat exchanger is appreciated. The change of the coefficient of performance machine after turning the cycle regenerative heat exchanger is analyzed. It is shown that the installation of a regenerator RVGRM cycle results in increased COP more than 30%. The simulation results show that the proposed model can be used to design and optimize gas refrigerator Stirling.

Scaling laws for gas–liquid flow in swirl vane separators

International Nuclear Information System (INIS)

Liu, Li; Bai, Bofeng

2016-01-01

Highlights: • Model for swirl vane separator performance is established with similarity criteria. • Scaling laws are developed to correlate downscale test with prototype separator. • Effects of key similarity criteria on separation performance are studied. • The vital role of droplet size distribution on separation performance is discussed. - Abstract: Laboratory tests on gas–liquid flow in swirl vane separators are usually carried out to help establish an experimental database for separator design and performance improvement. Such model tests are generally performed in the reduced scale and not on the actual working conditions. Though great efficiency is often obtainable in the reduced model, the performance of the full-sized prototype usually cannot be well predicted. To design downscale model tests and apply the experimental results to predict the prototype, a general relationship to correlate them is required. In this paper, the relation of the similitude-criterion concerning the pressure loss is presented by using the dimensionless analysis, and mathematical models for critical droplet diameter, grade efficiency and overall separation efficiency are established by analyzing the features of the droplet trajectory in gas swirling flow field. The essential similarity criteria accounting for pressure loss and separation efficiency are obtained, respectively. On this basis, the scaling laws which enable a comparison between the reduced model and the full-sized prototype under similar conditions are also developed. It is found that the overall separation efficiency is significantly affected by the size distribution of the small droplets, especially when the mean diameter is smaller than the critical droplet diameter.

Studies on as separation behaviour of polymer blending PI/PES hybrid mixed membrane: Effect of polymer concentration and zeolite loading

Directory of Open Access Journals (Sweden)

Ahmad Fauzi Ismail

2014-04-01

Full Text Available This study is performed primarily to investigate the effect of polymer concentration of polyimide/polyethersulfone (PI/PES blending on the gas separation performance of hybrid mixed matrix membrane. In this study, PI/ (PES–zeolite 4A mixed matrix membranes were casted using dry/wet phase inversion technique. The efefct of PI/PES concentrations and zeolite loading on the dope solution were investigated for gas separation performance. The results from the Field Emission Scanning Electron Microscopy (FESEM analysis confirmed that polymer concentration and zeolite loading was affected the morphology of membrane and gas separation performance. ‘Sieve-in-a-cage’ morphology observed the poor adhesion between polymer and zeolite at higher zeolite loading. The gas separation performance of the mixed matrix membranes were relatively higher compared to that of the neat polymeric membrane.

The initial study on supercritical water flow and heat transfer in square rod bundle channel with mixing vane

International Nuclear Information System (INIS)

Zuo Guoping; Cao Can; Yu Tao

2010-01-01

Three-dimensional rectangular channel with the mixing wine in supercritical water reactor was studied in the paper using the FLUENT software. The mixing wing elevation influence on temperature distribution and flow field were studied in the model. The results showed the mixing wing caused fluid circumferential flow, making flow hot and cold fluids mixed and fluid temperature uniform distribution, effectively improved the fuel rod surface temperature distribution and reduced hot temperature. Among the four cases of mixing wing elevation of 15, 30, 45 and 50 angle, 30 angle is the best case in improving temperature distribution. (authors)

Hybrid composites

CSIR Research Space (South Africa)

Jacob John, Maya

2009-04-01

Full Text Available mixed short sisal/glass hybrid fibre reinforced low density polyethylene composites was investigated by Kalaprasad et al [25].Chemical surface modifications such as alkali, acetic anhydride, stearic acid, permanganate, maleic anhydride, silane...

A Mixed Logical Dynamical-Model Predictive Control (MLD-MPC Energy Management Control Strategy for Plug-in Hybrid Electric Vehicles (PHEVs

Directory of Open Access Journals (Sweden)

Jing Lian

2017-01-01

Full Text Available Plug-in hybrid electric vehicles (PHEVs can be considered as a hybrid system (HS which includes the continuous state variable, discrete event, and operation constraint. Thus, a model predictive control (MPC strategy for PHEVs based on the mixed logical dynamical (MLD model and short-term vehicle speed prediction is proposed in this paper. Firstly, the mathematical model of the controlled PHEV is set-up to evaluate the energy consumption using the linearized models of core power components. Then, based on the recognition of driving intention and the past vehicle speed data, a nonlinear auto-regressive (NAR neural network structure is designed to predict the vehicle speed for known driving profiles of city buses and the predicted vehicle speed is used to calculate the total required torque. Next, a MLD model is established with appropriate constraints for six possible driving modes. By solving the objective function with the Mixed Integer Linear Programming (MILP algorithm, the optimal motor torque and the corresponding driving mode sequence within the speed prediction horizon can be obtained. Finally, the proposed energy control strategy shows substantial improvement in fuel economy in the simulation results.

A new low threshold bi-directional wind vane and its potential impact on unplanned atmospheric release prediction

International Nuclear Information System (INIS)

Parker, M.J.

1996-01-01

At the Savannah River Site, the Environmental Transport Group (ETG) maintains and develops a comprehensive meteorological monitoring program which employs bi-directional wind vanes (bivanes) for the measurement of horizontal and vertical wind direction and turbulence. Wind data collected near and below instrument starting thresholds under stable nighttime conditions with these bivanes can result in artificially large standard deviations of horizontal wind direction (σA). In one hypothetical case, downwind concentrations could be underestimated by a factor of 40 by using artificially high σA data in a Gaussian dispersion model. In an effort to improve low wind speed measurements of wind direction, a Cooperative Research and Development Agreement (CRADA) between Met One Instruments and the Westinghouse Savannah River Company (WSRC) has been created to improve the dynamic performance of the Met One Model 1585 Bi-Directional Wind Vane

Effect of halide-mixing on the switching behaviors of organic-inorganic hybrid perovskite memory

Science.gov (United States)

Hwang, Bohee; Gu, Chungwan; Lee, Donghwa; Lee, Jang-Sik

2017-03-01

Mixed halide perovskite materials are actively researched for solar cells with high efficiency. Their hysteresis which originates from the movement of defects make perovskite a candidate for resistive switching memory devices. We demonstrate the resistive switching device based on mixed-halide organic-inorganic hybrid perovskite CH3NH3PbI3-xBrx (x = 0, 1, 2, 3). Solvent engineering is used to deposit the homogeneous CH3NH3PbI3-xBrx layer on the indium-tin oxide-coated glass substrates. The memory device based on CH3NH3PbI3-xBrx exhibits write endurance and long retention, which indicate reproducible and reliable memory properties. According to the increase in Br contents in CH3NH3PbI3-xBrx the set electric field required to make the device from low resistance state to high resistance state decreases. This result is in accord with the theoretical calculation of migration barriers, that is the barrier to ionic migration in perovskites is found to be lower for Br- (0.23 eV) than for I- (0.29-0.30 eV). The resistive switching may be the result of halide vacancy defects and formation of conductive filaments under electric field in the mixed perovskite layer. It is observed that enhancement in operating voltage can be achieved by controlling the halide contents in the film.

Elaboration of hybrid materials by templating with mineral liquid crystals stabilization of a mixed sol of YSZ nanoparticles and V2O5 ribbon-like colloids

International Nuclear Information System (INIS)

Guiot, C.

2009-01-01

The purpose of this PhD was to investigate innovative soft chemistry ways to prepare hybrid materials with ordered nano-structures. Concretely, research were conducted on the development of a hybrid material made of an yttria-stabilized zirconia (YSZ) matrix templated by a mineral liquid crystal, namely V 2 O 5 . In aqueous solutions, vanadium oxide exhibits ribbon-like colloids of typical dimensions 1 nm x 25 nm x 500 nm, stabilized by a strong negative surface charge. Above a critical concentration, the anisotropic colloids assemble into a nematic liquid crystal, whose domains can be oriented within the same direction over a macroscopic range under a weak magnetic field. The idea is to use V 2 O 5 anisotropic colloids as a template for a hybrid material, taking advantage of their ordering behavior. Preliminary experiments revealed a strong reactivity between molecular compounds of zirconium and vanadium oxide. Therefore, the studies were directed toward the preparation of a mixed colloidal sol containing YSZ nanoparticles and vanadium oxide ribbon-like colloids, as a precursor sol for the intended hybrid material. The YSZ nanoparticles are obtained through an outstanding hydrothermal synthesis leading to a stable suspension of nanocrystalline particles of ca. 5 nm, in pure water. Providing a mixed sol of YSZ and V 2 O 5 is a key challenge for it implies the co-stabilization of two types of colloids having different shape, size and surface properties. Besides, the existence of V 2 O 5 in its ribbon-like form requires acidic conditions and very low ionic strength. The first part of this work was then dedicated to the study of electro-steric stabilization of zirconia suspension by addition of acidic poly-electrolytes. Different polymers with carboxylic and/or sulfonic acidic functions were investigated. Based on zeta potential measurements and adsorption isotherms, the influence of molecular weight and polymer charge were discussed. Among the studied polymers, poly

Change of performance of a horizontal wind turbine with V type tip vane%风力机加V型小翼后的性能变化

Institute of Scientific and Technical Information of China (English)

贾瑞博; 汪建文

2011-01-01

试验和数值模拟证明,在风力机叶片的叶尖添加小翼,可以提高风能转化效率.为了清楚地了解小翼对风力机动力放大的影响,文章基于叶轮周围流场的数值模拟结果,分析了加V型小翼和不加小翼的风力机流场-速度场和压力场特性.可以看出,小翼对风力机叶片叶端的影响较大,风力机叶尖的漩涡强度降低,能量转换效率提高.%It was proved that a tip vane could improve thewind turbine's efficiency by the test and the numerical simulation. In order to distinctly understand the power augmentation effect of the wind turbine by the tip vane, this paper analyzed the flow field of the wind turbine with the V type tip vane and without a tip vane, as well as the characteristics of the velocity field and the pressure field, which based on the numerical simulation result of the flow field of the wind turbine. The tip vane has more influence to the blade tip of the wind turbine. The vortex intensity around the blade tip was reduced and the energy transformation efficiency was improved.

Mixed DNA/Oligo(ethylene glycol) Functionalized Gold Surface Improve DNA Hybridization in Complex Media

International Nuclear Information System (INIS)

Lee, C.; Gamble, L.; Grainger, D.; Castner, D.

2006-01-01

Reliable, direct 'sample-to-answer' capture of nucleic acid targets from complex media would greatly improve existing capabilities of DNA microarrays and biosensors. This goal has proven elusive for many current nucleic acid detection technologies attempting to produce assay results directly from complex real-world samples, including food, tissue, and environmental materials. In this study, we have investigated mixed self-assembled thiolated single-strand DNA (ssDNA) monolayers containing a short thiolated oligo(ethylene glycol) (OEG) surface diluent on gold surfaces to improve the specific capture of DNA targets from complex media. Both surface composition and orientation of these mixed DNA monolayers were characterized with x-ray photoelectron spectroscopy (XPS) and near-edge x-ray absorption fine structure (NEXAFS). XPS results from sequentially adsorbed ssDNA/OEG monolayers on gold indicate that thiolated OEG diluent molecules first incorporate into the thiolated ssDNA monolayer and, upon longer OEG exposures, competitively displace adsorbed ssDNA molecules from the gold surface. NEXAFS polarization dependence results (followed by monitoring the N 1s→π* transition) indicate that adsorbed thiolated ssDNA nucleotide base-ring structures in the mixed ssDNA monolayers are oriented more parallel to the gold surface compared to DNA bases in pure ssDNA monolayers. This supports ssDNA oligomer reorientation towards a more upright position upon OEG mixed adlayer incorporation. DNA target hybridization on mixed ssDNA probe/OEG monolayers was monitored by surface plasmon resonance (SPR). Improvements in specific target capture for these ssDNA probe surfaces due to incorporation of the OEG diluent were demonstrated using two model biosensing assays, DNA target capture from complete bovine serum and from salmon genomic DNA mixtures. SPR results demonstrate that OEG incorporation into the ssDNA adlayer improves surface resistance to both nonspecific DNA and protein

Mapping of the lateral flow field in typical subchannels of a support grid with vanes

International Nuclear Information System (INIS)

McClusky, Heather L.; Holloway, Mary V.; Conover, Timothy A.; Beasley, Donald E.; Conner, Michael E.; Smith III, L. David

2003-01-01

Lateral flow fields in four subchannels of a model rod bundle fuel assembly are measured using particle image velocimetry. Vanes (split-vane pairs) are located on the downstream edge of the support grids in the rod bundle fuel assembly and generate swirling flow. Measurements are acquired at a nominal Reynolds number of 28,000 and for seven streamwise locations ranging from 1.4 to 17.0 hydraulic diameters downstream of the grid. The streamwise development of the lateral flow field is divided into two regions based on the lateral flow structure. In Region I, multiple vortices are present in the flow field and vortex interactions occur. Either a single circular vortex or a hairpin shaped flow structure is formed in Region II. Lateral kinetic energy, maximum lateral velocity, centroid of vorticity, radial profiles of azimuthal velocity, and angular momentum are employed as measures of the streamwise development of the lateral flow field. The particle image velocimetry measurements of the present study are compared with laser doppler velocimetry measurements taken for the identical support grids and flow condition. (author)

The Role of Free-Stream Turbulence on High Pressure Turbine Aero-Thermal Stage Interaction

Science.gov (United States)

Kopriva, James Earl

unstructured Hybrid LES aero-thermal predictions are found to be in close agreement with LES predictions and 4 times more computationally efficient. A sliding mesh approach is then used to understand the complex HPT vane and blade stage aero-thermal interaction at 0 and 20% inlet turbulence. A HPT blade has been designed to pair with the uncooled vane of Arts and Rouvroit (1992) to evaluate the impact of passage turbulence and vane wake on the downstream blade boundary layer as well as wake formation and evolution. The learnings from the statistical 2D pitch-line stage simulations are applied to a 3D annular representation of the geometry including endwalls and blade tip clearance to demonstrate the impact of secondary flows on the overall aero-thermal performance. Compared to the 2D pitchline predictions, the vane and blade overall mass average relative total pressure loss for the 3D geometry increases by 73 and 107%, respectively. The blade loss is shown to be largely driven by the formation of the tip vortex. Hybrid LES predictions show that by increasing stage inlet turbulence by 20% results in up to a 40% increase for the surface heat flux on the vane. However, the impact of stage inlet turbulence is found to be secondary compared to the periodic unsteadiness generated by the vane wake on the downstream blade surface heat transfer and mixing.

On development of RFQ vanes from beam dynamics data

International Nuclear Information System (INIS)

Chatterjee, Avik; Padhi, Rakesh; Banerjee, M.K.; Naik, Vaishali; Sanyal, Dirtha; Choudhury, Siddhartha De; Chakrabarti, Alok

2005-01-01

Simulation at critical steps of product development greatly helps to detect the design flaws at the earlier stage and gives a digital platform to iterate the design and process at the initial stage. This helps to reduce the risk of failure considerably and gives an alternative to reduce the number of physical prototypes for design validation. Modern concepts of virtual prototyping for predicting functional behaviour of a product and process are gaining momentum globally as it is the fully integrated approach to converge the concepts of functional design, Design for Manufacturing (DFM), Design for Assembly (DFA) and manufacturing process simulation. This concept has been partially implemented in development of RFQ (Radio Frequency Quadruple) vanes and the basic guidelines have been discussed. (author)

Investigation of the Optimal Omni-Direction-Guide-Vane Design for Vertical Axis Wind Turbines Based on Unsteady Flow CFD Simulation

Directory of Open Access Journals (Sweden)

Behzad Shahizare

2016-03-01

Full Text Available With soaring energy demands, the desire to explore alternate and renewable energy resources has become the focal point of various active research fronts. Therefore, the scientific community is revisiting the notion to tap wind resources in more rigorous and novel ways. In this study, a two-dimensional computational investigation of the vertical axis wind turbine (VAWT with omni-direction-guide-vane (ODGV is proposed to determine the effects of this guide vane. In addition, the mesh and time step (dt size dependency test, as well as the effect of the different turbulence models on results accuracy are investigated. Eight different shape ratios (R of the omni-direction-guide-vane were also examined in this study. Further, the CFD model is validated by comparing the numerical results with the experimental data. Validation results show a good agreement in terms of shape and trend in CFD simulation. Based on these results, all the shape ratios, except two ratios including 0.3 and 0.4 at TSR of 1.3 to 3, have a positive effect on the power and torque coefficient improvement. Moreover, results show that the best case has a shape ratio of 0.55, which improves the power coefficient by 48% and the torque coefficient up to 58%.

High performance hydraulic design techniques of mixed-flow pump impeller and diffuser

International Nuclear Information System (INIS)

Kim, Sung; Lee, Kyoung Yong; Kim, Joon Hyung; Kim, Jin Hyuk; Jung, Uk Hee; Choi, Young Seok

2015-01-01

In this paper, we describe a numerical study about the performance improvement of a mixed-flow pump by optimizing the design of the impeller and diffuser using a commercial computational fluid dynamics (CFD) code and design-of-experiments (DOE). The design variables of impeller and diffuser in the vane plane development were defined with a fixed meridional plane. The design variables were defined by the vane plane development, which indicates the blade-angle distributions and length of the impeller and diffuser. The vane plane development was controlled using the blade-angle in a fixed meridional plane. The blade shape of the impeller and diffuser were designed using a traditional method in which the inlet and exit angles are connected smoothly. First, the impeller optimum design was performed with impeller design variables. The diffuser optimum design was performed with diffuser design variables while the optimally designed impeller shape was fixed. The importance of the impeller and diffuser design variables was analyzed using 2 k factorial designs, and the design optimization of the impeller and diffuser design variables was determined using the response surface method (RSM). The objective functions were defined as the total head (Ht) and the total efficiency (ηt) at the design flow rate. The optimally designed model was verified using numerical analysis, and the numerical analysis results for both the optimum model and the reference model were compared to determine the reasons for the improved pump performance. A pump performance test was carried out for the optimum model, and its reliability was proved by a comparative analysis of the results of the numerical analysis and an experiment using the optimum model.

Genetic basis to hybrid inviability is more complex than hybrid male sterility in Caenorhabditis nematodes.

Science.gov (United States)

Bundus, Joanna D; Wang, Donglin; Cutter, Asher D

2018-04-07

Hybrid male sterility often evolves before female sterility or inviability of hybrids, implying that the accumulation of divergence between separated lineages should lead hybrid male sterility to have a more polygenic basis. However, experimental evidence is mixed. Here, we use the nematodes Caenorhabditis remanei and C. latens to characterize the underlying genetic basis of asymmetric hybrid male sterility and hybrid inviability. We demonstrate that hybrid male sterility is consistent with a simple genetic basis, involving a single X-autosome incompatibility. We also show that hybrid inviability involves more genomic compartments, involving diverse nuclear-nuclear incompatibilities, a mito-nuclear incompatibility, and maternal effects. These findings demonstrate that male sensitivity to genetic perturbation may be genetically simple compared to hybrid inviability in Caenorhabditis and motivates tests of generality for the genetic architecture of hybrid incompatibility across the breadth of phylogeny.

Numerical simulation of internal flow in mixed-flow waterjet propulsion

International Nuclear Information System (INIS)

Wu, T T; Pan, Z Y; Zhang, D Q; Jia, Y Y

2012-01-01

In order to reveal the internal flow characteristic of a mixed-flow waterjet propulsion, a mixed-flow waterjet propulsion under different conditions was simulated based on multi-reference frame(MRF), the standard k − ε turbulent model and SIMPLEC algorithm. The relationship between pump performance instability and internal flow was obtained. The numerical results showed that characteristic instability occurred at 0.65-0.67Q BEP , the reason is that the backflow on the vaned diffuser hub-side blocks the downstream flow from the impeller. Therefore, the flow separates on the pressure surface of the impeller outlet and a strong vortex is generated, then the characteristic instability appeared due to the instability of internal flow. Backflow was found in diffuser passage at 0.65 Q BEP and 0.85 Q BEP , as flow rate decreases, the backflow region and velocity increases. Pressure fluctuation at diffuser inlet and diffuser passages was severe at at 0.65 Q BEP . According to the numerical simulation, the mixed-flow waterjet propulsion has characteristic instability at partial flow rate condition.

2.5 MeV CW 4-vane RFQ accelerator design for BNCT applications

Science.gov (United States)

Zhu, Xiaowen; Wang, Hu; Lu, Yuanrong; Wang, Zhi; Zhu, Kun; Zou, Yubin; Guo, Zhiyu

2018-03-01

Boron Neutron Capture Therapy (BNCT) promises a bright future in cancer therapy for its highly selective destruction of cancer cells, using the 10B +n→7Li +4 He reaction. It offers a more satisfactory therapeutic effect than traditional methods for the treatment of malignant brain tumors, head and neck cancer, melanoma, liver cancer and so on. A CW 4-vane RFQ, operating at 162.5 MHz, provides acceleration of a 20 mA proton beam to 2.5 MeV, bombarding a liquid lithium target for neutron production with a soft neutron energy spectrum. The fast neutron yield is about 1.73×1013 n/s. We preliminarily develop and optimize a beam shaping assembly design for the 7Li(p, n)7Be reaction with a 2.5 MeV proton beam. The epithermal neutron flux simulated at the beam port will reach up to 1 . 575 ×109 n/s/cm2. The beam dynamics design, simulation and benchmark for 2.5 MeV BNCT RFQ have been performed with both ParmteqM (V3.05) and Toutatis, with a transmission efficiency higher than 99.6% at 20 mA. To ease the thermal management in the CW RFQ operation, we adopt a modest inter-vane voltage design (U = 65 kV), though this does increase the accelerator length (reaching 5.2 m). Using the well-developed 3D electromagnetic codes, CST MWS and ANSYS HFSS, we are able to deal with the complexity of the BNCT RFQ, taking the contribution of each component in the RF volume into consideration. This allows us to optimize the longitudinal field distribution in a full-length model. Also, the parametric modeling technique is of great benefit to extensive modifications and simulations. In addition, the resonant frequency tuning of this RFQ is studied, giving the tuning sensitivities of vane channel and wall channel as -16.3 kHz/°C and 12.4 kHz/°C, respectively. Finally, both the multipacting level of this RFQ and multipacting suppressing in the coaxial coupler are investigated.

Effects of Mie tip-vane on pressure distribution of rotor blade and power augmentation of horizontal axis wind turbine; Yokutan shoyoku Mie ben ni yoru suiheijiku fusha yokumenjo no atsuryoku bunpu no kaizen to seino kojo tono kankei

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Y.; Maeda, T.; Kamada, Y. [Mie Univ., Mie (Japan); Seto, H. [Mitsubishi Motors Corp., Tokyo (Japan)

2000-04-01

By recent developments of exclusive rotor blade, the efficiency of wind turbine is improved substantially. By measuring pressure on rotor blades of horizontal axis wind turbines rotating in wind tunnels, this report clarified relation between improvement of pressure distribution on main rotor blades by Mie vane and upgrade of wind turbine performance. The results under mentioned have been got by measuring pressure distribution on rotor blades, visualization by tuft, and measuring resistance of Mie vane. (1) The difference of pressure between suction surface and pressure surface on the end of rotor blade increase, and output power of wind turbine improves. (2) Vortex of blade end is inhibited by Mie vane. (3) The reason of reduction on wind turbine performance with Mie vane in aria of high rotating speed ratio is the increase of Mie vane flow resistance.(NEDO)

Influence of omni-directional guide vane on the performance of cross-flow rotor for urban wind energy

Science.gov (United States)

Wicaksono, Yoga Arob; Tjahjana, Dominicus Danardono Dwi Prija; Hadi, Syamsul

2018-02-01

Vertical axis wind turbine like cross-flow rotor have some advantage there are, high self-starting torque, low noise, and high stability; so, it can be installed in the urban area to produce electricity. But, the urban area has poor wind condition, so the cross-flow rotor needs a guide vane to increase its performance. The aim of this study is to determine experimentally the effect of Omni-Directional Guide Vane (ODGV) on the performance of a cross-flow wind turbine. Wind tunnel experiment has been carried out for various configurations. The ODGV was placed around the cross-flow rotor in order to increase ambient wind environment of the wind turbine. The maximum power coefficient is obtained as Cpmax = 0.125 at 60° wind direction. It was 21.46% higher compared to cross-flow wind turbine without ODGV. This result showed that the ODGV able to increase the performance of the cross-flow wind turbine.

Mixed-hybrid finite element method for the transport equation and diffusion approximation of transport problems

International Nuclear Information System (INIS)

Cartier, J.

2006-04-01

This thesis focuses on mathematical analysis, numerical resolution and modelling of the transport equations. First of all, we deal with numerical approximation of the solution of the transport equations by using a mixed-hybrid scheme. We derive and study a mixed formulation of the transport equation, then we analyse the related variational problem and present the discretization and the main properties of the scheme. We particularly pay attention to the behavior of the scheme and we show its efficiency in the diffusion limit (when the mean free path is small in comparison with the characteristic length of the physical domain). We present academical benchmarks in order to compare our scheme with other methods in many physical configurations and validate our method on analytical test cases. Unstructured and very distorted meshes are used to validate our scheme. The second part of this thesis deals with two transport problems. The first one is devoted to the study of diffusion due to boundary conditions in a transport problem between two plane plates. The second one consists in modelling and simulating radiative transfer phenomenon in case of the industrial context of inertial confinement fusion. (author)

3D computations of flow field in a guide vane blading designed by means of 2D model for a low head hydraulic turbine

International Nuclear Information System (INIS)

Krzemianowski, Z; Puzyrewski, R

2014-01-01

The paper presents the main parameters of the flow field behind the guide vane cascade designed by means of 2D inverse problem and following check by means of 3D commercial program ANSYS/Fluent applied for a direct problem. This approach of using different models reflects the contemporary design procedure for non-standardized turbomachinery stage. Depending on the model, the set of conservation equation to be solved differs, although the physical background remains the same. The example of computations for guide vane cascade for a low head hydraulic turbine is presented.

Proposal of a novel compact P-band magnetically insulated transmission line oscillator with inclined vanes

Science.gov (United States)

Zhang, Xiaoping; Dang, Fangchao; Li, Yangmei; Jin, Zhenxing

2015-06-01

In this paper, we present a novel compact P-band magnetically insulated transmission line oscillator (MILO) with specially inclined slow-wave-structure (SWS) vanes to decrease its total dimension and weight. The dispersion characteristics of the inclined SWS are investigated in detail and made comparisons with that of the traditional straight SWS. The results show that the inclined SWS is more advantageous in operating on a steady frequency in a wide voltage range and has a better asymmetric mode segregation and a relatively large band-gap between the TM00 and TM01 modes which are in favor of avoiding the asymmetric and transverse mode competition. Besides, the transverse dimension of the proposed novel inclined SWS with the same operation frequency is decreased by about 50%, and correspondingly the device volume shrinks remarkably to its 0.35 times. In particle-in-cell simulation, the electron bunching spokes are obviously formed in the inclined SWS, and a P-band high-power microwave with a power of 5.8 GW, frequency of 645 MHz, and efficiency of 17.2% is generated by the proposed device, which indicates the feasibility of the compact design with the inclined vanes at the P-band.

Mixed and mixed-hybrid elements for the diffusion equation

International Nuclear Information System (INIS)

Coulomb, F.; Fedon-Magnaud, C.

1987-04-01

To solve the diffusion equation, one often uses a Lagrangian finite element method. We want to introduce the mixed elements which allow a simultaneous approximation of the same order for the flux and its gradient. Though the linear systems are not positive definite, it is possible to make them so by eliminating some of the unknowns

NASA Workshop on Hybrid (Mixed-Actuator) Spacecraft Attitude Control

Science.gov (United States)

Dennehy, Cornelius J.; Kunz, Nans

2014-01-01

At the request of the Science Mission Directorate Chief Engineer, the NASA Technical Fellow for Guidance, Navigation & Control assembled and facilitated a workshop on Spacecraft Hybrid Attitude Control. This multi-Center, academic, and industry workshop, sponsored by the NASA Engineering and Safety Center (NESC), was held in April 2013 to unite nationwide experts to present and discuss the various innovative solutions, techniques, and lessons learned regarding the development and implementation of the various hybrid attitude control system solutions investigated or implemented. This report attempts to document these key lessons learned with the 16 findings and 9 NESC recommendations.

Influence of Mixed Solvent on the Electrochemical Property of Hybrid Capacitor.

Science.gov (United States)

Lee, Byunggwan; Yoon, J R

2015-11-01

The hybrid capacitors (2245 size, cylindrical type) were prepared by using activated carbon cathode and Li4Ti5O12 anode. In order to improve the cell operation at high temperature range, propylene carbonate (PC) was used in combination with acetonitrile (AN) with volume ratio of 7:3, 5:5, and 3:7, respectively. We investigated the electrochemical behavior of the hybrid capacitors that enabled cell operation with stability at high temperature. The organic electrolyte of hybrid capacitor containing PC and AN with a volume ratio 7:3 intended to exhibit highly reversible cycle performance with good capacity retention at 60 degrees C after 2200 cycles. From this study, it has been found that the very strong influence of the solvent nature on the characteristics of hybrid capacitor, and the difference in performance associated with the two solvents.

Cooling Strategies for Vane Leading Edges in a Syngas Environment Including Effects of Deposition and Turbulence

Energy Technology Data Exchange (ETDEWEB)

Ames, Forrest [Univ. of North Dakota, Grand Forks, ND (United States); Bons, Jeffrey [Univ. of North Dakota, Grand Forks, ND (United States)

2014-09-30

The Department of Energy has goals to move land based gas turbine systems to alternate fuels including coal derived synthetic gas and hydrogen. Coal is the most abundant energy resource in the US and in the world and it is economically advantageous to develop power systems which can use coal. Integrated gasification combined cycles are (IGCC) expected to allow the clean use of coal derived fuels while improving the ability to capture and sequester carbon dioxide. These cycles will need to maintain or increase turbine entry temperatures to develop competitive efficiencies. The use of coal derived syngas introduces a range of potential contaminants into the hot section of the gas turbine including sulfur, iron, calcium, and various alkali metals. Depending on the effectiveness of the gas clean up processes, there exists significant likelihood that the remaining materials will become molten in the combustion process and potentially deposit on downstream turbine surfaces. Past evidence suggests that deposition will be a strong function of increasing temperature. Currently, even with the best gas cleanup processes a small level of particulate matter in the syngas is expected. Consequently, particulate deposition is expected to be an important consideration in the design of turbine components. The leading edge region of first stage vanes most often have higher deposition rates than other areas due to strong fluid acceleration and streamline curvature in the vicinity of the surface. This region remains one of the most difficult areas in a turbine nozzle to cool due to high inlet temperatures and only a small pressure ratio for cooling. The leading edge of a vane often has relatively high heat transfer coefficients and is often cooled using showerhead film cooling arrays. The throat of the first stage nozzle is another area where deposition potentially has a strongly adverse effect on turbine performance as this region meters the turbine inlet flow. Based on roughness

Effect of 17 x 17 fuel assembly geometry on interchannel thermal mixing

International Nuclear Information System (INIS)

Motley, F.E.; Wenzell, A.H.; Cadek, F.F.

1975-01-01

A test to determine the value of the thermal diffusion coefficient (TDC) in the 17 x 17 fuel assembly geometry was conducted. The test section was a 5 x 5 rod bundle with a radial power difference of 4.5 to 1. The rod OD and pitch are identical to the 17 x 17 fuel assembly, as is the mixing vane grid design. The value of thermal diffusion coefficient (TDC) was determined by matching the experimental exit enthalpy distribution to that predicted by the THINC computer code. The mean value of TDC for the 17 x 17 fuel assembly geometry is TDC = .059. 6 references

Rapid One-Pot Microwave Synthesis of Mixed-Linker Hybrid Zeolitic-Imidazolate Framework Membranes for Tunable Gas Separations.

Science.gov (United States)

Hillman, Febrian; Brito, Jordan; Jeong, Hae-Kwon

2018-02-14

The relatively slow and complex fabrication processes of polycrystalline metal-organic framework (MOF) membranes often times restrict their way to commercialization, despite their potential for molecular separation applications. Herein, we report a rapid one-pot microwave synthesis of mixed-linker hybrid zeolitic-imidazolate framework (ZIF) membranes consisting of 2-methylimidazolate (ZIF-8 linker) and benzimidazolate (ZIF-7 linker) linkers, termed ZIF-7-8 membranes. The fast-volumetric microwave heating in conjunction with a unique counter diffusion of metal and linker solutions enabled unprecedented rapid synthesis of well-intergrown ZIF-7-8 membranes in ∼90 s, the fastest MOF membrane preparation up to date. Furthermore, we were able to tune the molecular sieving properties of the ZIF-7-8 membranes by varying the benzimidazole-to-2-methylimidazole (bIm-to-mIm) linker ratio in the hybrid frameworks. The tuning of their molecular sieving properties led to the systematic change in the permeance and selectivity of various small gases. The unprecedented rapid synthesis of well-intergrown ZIF-7-8 membranes with tunable molecular sieving properties is an important step forward for the commercial gas separation applications of ZIF membranes.

A Hybrid Approach to Teaching Managerial Economics

Science.gov (United States)

Metzgar, Matthew

2014-01-01

Many institutions in higher education are experimenting with hybrid teaching approaches to undergraduate courses. Online resources may provide a number of advantages to students as compared to in-class approaches. Research regarding the effectiveness of hybrid approaches is mixed and still accumulating. This paper discusses the use of a hybrid…

Turbine blade and vane heat flux sensor development, phase 2

Science.gov (United States)

Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

1985-01-01

The development of heat flux sensors for gas turbine blades and vanes and the demonstration of heat transfer measurement methods are reported. The performance of the heat flux sensors was evaluated in a cylinder in cross flow experiment and compared with two other heat flux measurement methods, the slug calorimeter and a dynamic method based on fluctuating gas and surface temperature. Two cylinders, each instrumented with an embedded thermocouple sensor, a Gardon gauge, and a slug calorimeter, were fabricated. Each sensor type was calibrated using a quartz lamp bank facility. The instrumented cylinders were then tested in an atmospheric pressure combustor rig at conditions up to gas stream temperatures of 1700K and velocities to Mach 0.74. The test data are compared to other measurements and analytical prediction.

Prospects for the domestic production of large-sized cast blades and vanes for industrial gas turbines

Science.gov (United States)

Kazanskiy, D. A.; Grin, E. A.; Klimov, A. N.; Berestevich, A. I.

2017-10-01

Russian experience in the production of large-sized cast blades and vanes for industrial gas turbines is analyzed for the past decades. It is noted that the production of small- and medium-sized blades and vanes made of Russian alloys using technologies for aviation, marine, and gas-pumping turbines cannot be scaled for industrial gas turbines. It is shown that, in order to provide manufacturability under large-scale casting from domestic nickel alloys, it is necessary to solve complex problems in changing their chemical composition, to develop new casting technologies and to optimize the heat treatment modes. An experience of PAO NPO Saturn in manufacturing the blades and vanes made of ChS88U-VI and IN738-LC foundry nickel alloys for the turbines of the GTE-110 gas turbine unit is considered in detail. Potentialities for achieving adopted target parameters for the mechanical properties of working blades cast from ChS88UM-VI modified alloy are established. For the blades made of IN738-LC alloy manufactured using the existing foundry technology, a complete compliance with the requirements of normative and technical documentation has been established. Currently, in Russia, the basis of the fleet of gas turbine plants is composed by foreign turbines, and, for the implementation of the import substitution program, one can use the positive experience of PAO NPO Saturn in casting blades from IN738-LC alloy based on a reverse engineering technique. A preliminary complex of studies of the original manufacturer's blades should be carried out, involving, first of all, the determination of geometric size using modern measurement methods as well as the studies on the chemical compositions of the used materials (base metal and protective coatings). Further, verifying the constructed calculation models based on the obtained data, one could choose available domestic materials that would meet the operating conditions of the blades according to their heat resistance and corrosion

Computational Fluid Dynamics (CFD) Analyses in Support of Space Shuttle Main Engine (SSME) Heat Exchanger (HX) Vane Cracking Investigation

Science.gov (United States)

Garcia, Roberto; Benjamin, Theodore G.; Cornelison, J.; Fredmonski, A. J.

1993-01-01

Integration issues involved with installing the alternate turbopump (ATP) High Pressure Oxygen Turbopump (HPOTP) into the SSME have raised questions regarding the flow in the HPOTP turnaround duct (TAD). Steady-state Navier-Stokes CFD analyses have been performed by NASA and Pratt & Whitney (P&W) to address these questions. The analyses have consisted of two-dimensional axisymmetric calculations done at Marshall Space Flight Center and three-dimensional calculations performed at P&W. These analyses have identified flowfield differences between the baseline ATP and the Rocketdyne configurations. The results show that the baseline ATP configuration represents a more severe environment to the inner HX guide vane. This vane has limited life when tested in conjunction with the ATP but infinite life when tested with the current SSME HPOTP. The CFD results have helped interpret test results and have been used to assess proposed redesigns. This paper includes details of the axisymmetric model, its results, and its contribution towards resolving the problem.

Experimental and theoretical assessment of flexural properties of hybrid natural fibre composites

DEFF Research Database (Denmark)

Raghavalu Thirumalai, Durai Prabhakaran; Toftegaard, Helmuth Langmaack; Markussen, Christen Malte

2014-01-01

The concept of hybridization of natural fibre composites with synthetic fibres is attracting increasing scientific attention. The present study addresses the flexural properties of hybrid flax/glass/epoxy composites to demonstrate the potential benefits of hybridization. The study covers both...... experimental and theoretical assessments. Composite laminates with different hybrid fibre mixing ratios and different layer configurations were manufactured, and their volumetric composition and flexural properties were measured. The relationship between volume fractions in the composites is shown to be well...... predicted as a function of the hybrid fibre mixing ratio. The flexural modulus of the composites is theoretically assessed by using micromechanical models and laminate theory. The model predictions are compared with the experimentally determined flexural properties. Both approaches show that the flexural...

Modeling of Hybrid Growth Wastewater Bio-reactor

International Nuclear Information System (INIS)

EI Nashaei, S.; Garhyan, P.; Prasad, P.; Abdel Halim, H.S.; Ibrahim, G.

2004-01-01

The attached/suspended growth mixed reactors are considered one of the recently tried approaches to improve the performance of the biological treatment by increasing the volume of the accumulated biomass in terms of attached growth as well as suspended growth. Moreover, the domestic WW can be easily mixed with a high strength non-hazardous industrial wastewater and treated together in these bio-reactors if the need arises. Modeling of Hybrid hybrid growth wastewater reactor addresses the need of understanding the rational of such system in order to achieve better design and operation parameters. This paper aims at developing a heterogeneous mathematical model for hybrid growth system considering the effect of diffusion, external mass transfer, and power input to the system in a rational manner. The model will be based on distinguishing between liquid/solid phase (bio-film and bio-floc). This model would be a step ahead to the fine tuning the design of hybrid systems based on the experimental data of a pilot plant to be implemented in near future

LOX/LH2 vane pump for auxiliary propulsion systems

Science.gov (United States)

Hemminger, J. A.; Ulbricht, T. E.

1985-01-01

Positive displacement pumps offer potential efficiency advantages over centrifugal pumps for future low thrust space missions. Low flow rate applications, such as space station auxiliary propulsion or dedicated low thrust orbiter transfer vehicles, are typical of missions where low flow and high head rise challenge centrifugal pumps. The positive displacement vane pump for pumping of LOX and LH2 is investigated. This effort has included: (1) a testing program in which pump performance was investigated for differing pump clearances and for differing pump materials while pumping LN2, LOX, and LH2; and (2) an analysis effort, in which a comprehensive pump performance analysis computer code was developed and exercised. An overview of the theoretical framework of the performance analysis computer code is presented, along with a summary of analysis results. Experimental results are presented for pump operating in liquid nitrogen. Included are data on the effects on pump performance of pump clearance, speed, and pressure rise. Pump suction performance is also presented.

A Study of Ion-Ion Hybrid Instability in the Mixed Plasma

Directory of Open Access Journals (Sweden)

Soo-Yong Kim

1987-12-01

Full Text Available There are more oxygen ions than hydrogen ions in the auroral field zone. We consider both analytic and numerical simulation study of the heating of hydrogen and oxygen ions by auroral electrons. With the low drift speed of electron beams, the ion-ion hybrid wave becomes unstable instead of the lower hybrid wave so that a preferential heating of oxygen ions occurs.

Isotopic disequilibrium among commingled hybrid magmas: Evidence for a two-stage magma mixing-commingling process in the Mt. Perkins Pluton, Arizona

International Nuclear Information System (INIS)

Metcalf, R.V.; Smith, E.I.; Reed, R.C.

1995-01-01

The syn-extensional Miocene Mt. Perkins pluton, northwestern Arizona, cooled rapidly due to its small size (6 km 2 ) and shallow emplacement (7.5 km) and allows examination of commingled rocks that experienced little isotopic exchange. Within the pluton, quartz dioritic to granodioritic host rocks (58-68 wt% SiO 2 ) enclose dioritic enclaves (50-55 wt% SiO 2 ) and a portion contains enclave-free granodiorite (70-74 wt% SiO 2 ). Fine-grained, crenulate enclave margins and a lack of advanced mixing structures (e.g., schlieren, flow fabrics, etc.) indicate an incipient stage of commingling. Isotopic variation between enclaves and enclosing host rocks is large (6.8 to 10.6 ε Nd units; 0.0036 to 0.0046 87 Sr/ 86 Sr units), suggesting isotopic disequilibrium. Comparison of an enclave core and rim suggests that isotopic exchange with the host magma was limited to the enclave rim. Enclaves and hosts collectively form a calc-alkaline suite exhibiting a large range of ε Nd (+1.2 to -12.5) and initial 87 Sr/ 86 Sr (0.705 to 0.71267) with a correlation among ε Nd , initial 87 Sr/ 86 Sr, and major and trace element compositions. Modeling suggests that the suite formed by magma hybridization involving magma mixing accompanied by fractional crystallization. The magma mixing must have predated commingling at the present exposure level and indicates a larger mixing chamber at depth. Isotopic and trace element data suggests mixing end-members were asthenospheric mantle-derived mafic and crustal-derived felsic magmas. Fractional crystallization facilitated mixing by reducing the rheological contrasts between the mafic and felsic mixing end-members. 58 refs., 11 figs., 3 tabs

The First Record of Case of the Imperial Eagle and the Steppe Eagle Successful Breeding in the Mixed Pair in Western Kazakhstan and Records of Probable Hybrids of These Species in Russia and Kazakhstan

Directory of Open Access Journals (Sweden)

Igor V. Karyakin

2016-04-01

Full Text Available Facts mentioned in paper give evidence of the possibility of forming the mixed pairs between Steppe and Imperial Eagles, breeding success and fertility of hybrids. All the observed mixed pairs were found in the contact zone of the two species on the periphery of the Steppe Eagle breeding range under conditions of either decrease in numbers of one species (Steppe Eagle and the growth of another (in Western Kazakhstan, or decline in numbers of both species and the lack of birds of their own species (in Dauria. Considering the fact that the number of Steppe Eagles continues to decline, the hybridization process may amplify and this phenomenon requires a more thorough examination.

Challenges in Using Mix Methods in Evaluation

OpenAIRE

Stefan COJOCARU

2010-01-01

This article explores the debates between quantitative and qualitative methods in the evaluation process, analyzes the challenges about methodological mix in terms of credibility and validity of data and tools, and the evaluation findings. Beyond the epistemological contradictions, it seems that, in terms of usefulness, the mixing of methods is a practical solution, along with hybrids theories, able to provide information to improve the sufficiency of the program. Mixing methods is also a wa...

Polyfunctional inorganic-organic hybrid materials: an unusual kind of NLO active layered mixed metal oxalates with tunable magnetic properties and very large second harmonic generation.

Science.gov (United States)

Cariati, Elena; Macchi, Roberto; Roberto, Dominique; Ugo, Renato; Galli, Simona; Casati, Nicola; Macchi, Piero; Sironi, Angelo; Bogani, Lapo; Caneschi, Andrea; Gatteschi, Dante

2007-08-01

Mixed M(II)/M(III) metal oxalates, as "stripes" connected through strong hydrogen bonding by para-dimethylaminobenzaldeide (DAMBA) and water, form an organic-inorganic 2D network that enables segregation in layers of the cationic organic NLO-phore trans-4-(4-dimethylaminostyryl)-1-methylpyridinium, [DAMS+]. The crystalline hybrid materials obtained have the general formula [DAMS]4[M2M'(C2O4)6].2DAMBA.2H2O (M = Rh, Fe, Cr; M' = Mn, Zn), and their overall three-dimensional packing is non-centrosymmetric and polar, therefore suitable for second harmonic generation (SHG). All the compounds investigated are characterized by an exceptional SHG activity, due both to the large molecular quadratic hyperpolarizability of [DAMS+] and to the efficiency of the crystalline network which organizes [DAMS+] into head-to-tail arranged J-type aggregates. The tunability of the pairs of metal ions allows exploiting also the magnetic functionality of the materials. Examples containing antiferro-, ferro-, and ferri-magnetic interactions (mediated by oxalato bridges) are obtained by coupling proper M(III) ions (Fe, Cr, Rh) with M(II) (Mn, Zn). This shed light on the role of weak next-nearest-neighbor interactions and main nearest-neighbor couplings along "stripes" of mixed M(II)/M(III) metal oxalates of the organic-inorganic 2D network, thus suggesting that these hybrid materials may display isotropic 1D magnetic properties along the mixed M(II)/M(III) metal oxalates "stripes".

The design, simulation and testing of an urban vertical axis wind turbine with the omni-direction-guide-vane

International Nuclear Information System (INIS)

Chong, W.T.; Fazlizan, A.; Poh, S.C.; Pan, K.C.; Hew, W.P.; Hsiao, F.B.

2013-01-01

Graphical abstract: Solar energy, renewable energy, urban wind energy, environment, augmented wind turbine. Highlights: ► A system for on-site wind–solar hybrid power generation and rain water collection. ► The omni-direction-guide-vane (ODGV) overcomes the weak wind and turbulence conditions in urban areas. ► The ODGV improves the wind turbine performance by speeding-up and guiding the wind. ► The ODGV is designed to blend into the building architecture with safety enhancement. ► The wind tunnel test and CFD simulation results are presented. - Abstract: A novel omni-direction-guide-vane (ODGV) that surrounds a vertical axis wind turbine (VAWT) is designed to improve the wind turbine performance. Wind tunnel testing was performed to evaluate the performance of a 5-bladed (Wortmann FX63-137 airfoil) H-rotor wind turbine, with and without the integration of the ODGV. The test was conducted using a scaled model turbine which was constructed to simulate the VAWT enclosed by the ODGV placed on a building. The VAWT shows an improvement on its self-starting behavior where the cut-in speed was reduced with the integration of the ODGV. Since the VAWT is able to self-start at a lower wind speed, the working hour of the wind turbine would increase. At a wind speed of 6 m/s and under free-running condition (only rotor inertia and bearing friction were applied), the ODGV helps to increase the rotor rotational speed by 182%. With extra load application at the same wind speed (6 m/s), the wind turbine power output was increased by 3.48 times at its peak torque with the aid of the ODGV. The working concept of the ODGV is to minimize the negative torque zone of a lift-type VAWT and to reduce turbulence and rotational speed fluctuation. It was verified by re-simulating the torque coefficient data of a single bladed (NACA 0015 airfoil) VAWT published by the Sandia National Laboratories. From the simulation results, with the presence of the ODGV, it was shown that the

Extension of the Vane Pump-Grinder Technology to Manufacture Finely Dispersed Meat Batters.

Science.gov (United States)

Irmscher, Stefan B; Gibis, Monika; Herrmann, Kurt; Oechsle, Anja Maria; Kohlus, Reinhard; Weiss, Jochen

2016-03-01

A vane pump-grinder system was extended to enable the manufacture of finely dispersed emulsion-type sausages by constructing and attaching a high-shear homogenizer at the outlet. We hypothesized that the dispersing capabilities of the extended system may be improved to the point of facilitating meat-fat emulsification due to an overall increased volumetric energy input EV . Coarsely ground raw material mixtures were processed to yield meat batters at varying volume flow rates (10 to 60 L/min) and rotational rotor speeds of the homogenizer nrotor (1000 to 3400 rpm). The normalized torques acting on pump, grinder, and homogenizer motors were recorded and unit power consumptions were calculated. The structure of the manufactured meat batters and sausages were analyzed via image analysis. Key physicochemical properties of unheated and heated batters, that is, texture, water-binding, color, and solubilized protein were determined. The mean diameter d10 of the visible lean meat particles varied between 352 and 406 μm whereas the mean volume-surface diameter d32 varied between 603 and 796 μm. The lightness L* ranged from 66.2 to 70.7 and correlated with the volumetric energy input and product structure. By contrast, varying process parameters did not impact color values a* (approximately 11) and b* (approximately 8). Interestingly, water-binding and protein solubilization were not affected. An exponential process-structure relationship was identified allowing manufacturers to predict product properties as a function of applied process parameters. Raw material mixtures can be continuously comminuted, emulsified, and subsequently filled into casings using an extended vane pump-grinder. © 2016 Institute of Food Technologists®

From Object to Subject: Hybrid Identities of Indigenous Women in Science

Science.gov (United States)

McKinley, Elizabeth

2008-01-01

The use of hybridity today suggests a less coherent, unified and directed process than that found in the Enlightenment science's cultural imperialism, but regardless of this neither concept exists outside power and inequality. Hence, hybridity raises the question of the terms of the mixture and the conditions of mixing. Cultural hybridity produced…

A Numerical Study on the Improvement of Suction Performance and Hydraulic Efficiency for a Mixed-Flow Pump Impeller

Directory of Open Access Journals (Sweden)

Sung Kim

2014-01-01

Full Text Available This paper describes a numerical study on the improvement of suction performance and hydraulic efficiency of a mixed-flow pump by impellers. The design of these impellers was optimized using a commercial CFD (computational fluid dynamics code and DOE (design of experiments. The design variables of meridional plane and vane plane development were defined for impeller design. In DOE, variables of inlet part were selected as main design variables in meridional plane, and incidence angle was selected in vane plane development. The verification of the experiment sets that were generated by 2k factorial was done by numerical analysis. The objective functions were defined as the NPSHre (net positive suction head required, total efficiency, and total head of the impellers. The importance of the geometric design variables was analyzed using 2k factorial designs. The interaction between the NPSHre and total efficiency, according to the meridional plane and incidence angle, was discussed by analyzing the 2k factorial design results. The performance of optimally designed model was verified by experiments and numerical analysis and the reliability of the model was retained by comparison of numerical analysis and comparative analysis with the reference model.

On the conditions of magma mixing and its bearing on andesite production in the crust.

Science.gov (United States)

Laumonier, Mickael; Scaillet, Bruno; Pichavant, Michel; Champallier, Rémi; Andujar, Joan; Arbaret, Laurent

2014-12-15

Mixing between magmas is thought to affect a variety of processes, from the growth of continental crust to the triggering of volcanic eruptions, but its thermophysical viability remains unclear. Here, by using high-pressure mixing experiments and thermal calculations, we show that hybridization during single-intrusive events requires injection of high proportions of the replenishing magma during short periods, producing magmas with 55-58 wt% SiO2 when the mafic end-member is basaltic. High strain rates and gas-rich conditions may produce more felsic hybrids. The incremental growth of crustal reservoirs limits the production of hybrids to the waning stage of pluton assembly and to small portions of it. Large-scale mixing appears to be more efficient at lower crustal conditions, but requires higher proportions of mafic melt, producing more mafic hybrids than in shallow reservoirs. Altogether, our results show that hybrid arc magmas correspond to periods of enhanced magma production at depth.

Synthesis of poly(ethylene oxide)-silica hybrids

International Nuclear Information System (INIS)

Ishak Manaf

2002-01-01

A hybrid material incorporating silica networks in poly (ethylene oxide) was produced using the sol-gel process from solution mixtures of poly (ethylene oxide) dissolved in water and partially polymerized tetraethylorthosilicate (TEOS) with and without compatibilisation agent. These mixtures were converted into films by solvent evaporation and drying them in an air-circulating oven at 60 degree C. Depending on the alkoxysilane solution composition and several mixing parameters, different morphologies were obtained, varying from semi-interpenetrating networks of PEO within highly cross linked silica chains, to finely dispersed heterogeneous system exhibiting either co-continuous or particulate microstructure. The influence of pH, type of solvents, mixing temperatures and time, as well as the nature of compatibiliser was found to be extremely important in controlling the morphology and properties of the fine hybrid films. It was found that compatibilisation of PEO-SiO 2 hybrid system is achieved exclusively with the use of γ-glycidyloxypropyltrimethoxysilane (GOTMS) coupling agent. (Author)

Large eddy simulations of flow and mixing in jets and swirl flows: application to a gas turbine

Energy Technology Data Exchange (ETDEWEB)

Schluter, J.U.

2000-07-01

a last step all parts of the burner investigated as detached objects are assembled and a computation of a 20 deg.segment of the burner is made. Flow features, like vane flow separations and mixing quality are examined. Finally, burner modifications are proposed and their effect discussed. Emphasis is put on the suppression of large scale structures in the combustion chamber, which are suspected to be one source of combustion instabilities. (author)

Control and design of volumetric composition in pultruded hybrid fibre composites

DEFF Research Database (Denmark)

Madsen, Bo; Hashemi, Fariborz; Tahir, Paridah

2016-01-01

composition (i.e. volume fractions of fibres, matrix and porosity) in hybrid fibre composites. The model is based on a constant local fibre volume fraction criterion. Good agreement is found between model predictions and experimental data of pultruded hybrid kenaf/glass fibre composites with variable hybrid...... fibre weight mixing ratios. To demonstrate the suitability of the model, simulations are performed for four different cases of volumetric composition in hybrid kenaf/glass composites....

The GOSTT concept and hybrid mixed/virtual/augmented reality environment radioguided surgery

International Nuclear Information System (INIS)

Valdés Olmos, R. A.; Van Leeuwen, F. W. B.; Vidal-Sicart, S.; Giammarile, F.; Zaknun, J. J.; Mariani, G.

2014-01-01

The popularity gained by the sentinel lymph node (SLN) procedure in the last two decades did increase the interest of the surgical disciplines for other applications of radioguided surgery. An example is the gamma-probe guided localization of occult or difficult to locate neoplastic lesions. Such guidance can be achieved by intralesional delivery (ultrasound, stereotaxis or CT) of a radiolabelled agent that remains accumulated at the site of the injection. Another possibility rested on the use of systemic administration of a tumour-seeking radiopharmaceutical with favourable tumour accumulation and retention. On the other hand, new intraoperative imaging devices for radioguided surgery in complex anatomical areas became available. All this a few years ago led to the delineation of the concept Guided intraOperative Scintigraphic Tumour Targeting (GOSTT) to include the whole spectrum of basic and advanced nuclear medicine procedures required for providing a roadmap that would optimise surgery. The introduction of allied signatures using, e.g. hybrid tracers for simultaneous detection of the radioactive and fluorescent signals did amply the GOSTT concept. It was now possible to combine perioperative nuclear medicine imaging with the superior resolution of additional optical guidance in the operating room. This hybrid approach is currently in progress and probably will become an important model to follow in the coming years. A cornerstone in the GOSTT concept is constituted by diagnostic imaging technologies like SPECT/CT. SPECT/CT was introduced halfway the past decade and was immediately incorporated into the SLN procedure. Important reasons attributing to the success of SPECT/CT were its combination with lymphoscintigraphy, and the ability to display SLNs in an anatomical environment. This latter aspect has significantly been improved in the new generation of SPECT/CT cameras and provides the base for the novel mixed reality protocols of image-guided surgery. In

The GOSTT concept and hybrid mixed/virtual/augmented reality environment radioguided surgery.

Science.gov (United States)

Valdés Olmos, R A; Vidal-Sicart, S; Giammarile, F; Zaknun, J J; Van Leeuwen, F W; Mariani, G

2014-06-01

The popularity gained by the sentinel lymph node (SLN) procedure in the last two decades did increase the interest of the surgical disciplines for other applications of radioguided surgery. An example is the gamma-probe guided localization of occult or difficult to locate neoplastic lesions. Such guidance can be achieved by intralesional delivery (ultrasound, stereotaxis or CT) of a radiolabelled agent that remains accumulated at the site of the injection. Another possibility rested on the use of systemic administration of a tumour-seeking radiopharmaceutical with favourable tumour accumulation and retention. On the other hand, new intraoperative imaging devices for radioguided surgery in complex anatomical areas became available. All this a few years ago led to the delineation of the concept Guided intraOperative Scintigraphic Tumour Targeting (GOSTT) to include the whole spectrum of basic and advanced nuclear medicine procedures required for providing a roadmap that would optimise surgery. The introduction of allied signatures using, e.g. hybrid tracers for simultaneous detection of the radioactive and fluorescent signals did amply the GOSTT concept. It was now possible to combine perioperative nuclear medicine imaging with the superior resolution of additional optical guidance in the operating room. This hybrid approach is currently in progress and probably will become an important model to follow in the coming years. A cornerstone in the GOSTT concept is constituted by diagnostic imaging technologies like SPECT/CT. SPECT/CT was introduced halfway the past decade and was immediately incorporated into the SLN procedure. Important reasons attributing to the success of SPECT/CT were its combination with lymphoscintigraphy, and the ability to display SLNs in an anatomical environment. This latter aspect has significantly been improved in the new generation of SPECT/CT cameras and provides the base for the novel mixed reality protocols of image-guided surgery. In

A hybrid fault diagnosis approach based on mixed-domain state features for rotating machinery.

Science.gov (United States)

Xue, Xiaoming; Zhou, Jianzhong

2017-01-01

To make further improvement in the diagnosis accuracy and efficiency, a mixed-domain state features data based hybrid fault diagnosis approach, which systematically blends both the statistical analysis approach and the artificial intelligence technology, is proposed in this work for rolling element bearings. For simplifying the fault diagnosis problems, the execution of the proposed method is divided into three steps, i.e., fault preliminary detection, fault type recognition and fault degree identification. In the first step, a preliminary judgment about the health status of the equipment can be evaluated by the statistical analysis method based on the permutation entropy theory. If fault exists, the following two processes based on the artificial intelligence approach are performed to further recognize the fault type and then identify the fault degree. For the two subsequent steps, mixed-domain state features containing time-domain, frequency-domain and multi-scale features are extracted to represent the fault peculiarity under different working conditions. As a powerful time-frequency analysis method, the fast EEMD method was employed to obtain multi-scale features. Furthermore, due to the information redundancy and the submergence of original feature space, a novel manifold learning method (modified LGPCA) is introduced to realize the low-dimensional representations for high-dimensional feature space. Finally, two cases with 12 working conditions respectively have been employed to evaluate the performance of the proposed method, where vibration signals were measured from an experimental bench of rolling element bearing. The analysis results showed the effectiveness and the superiority of the proposed method of which the diagnosis thought is more suitable for practical application. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Peptoid-Peptide hybrid backbone architectures

DEFF Research Database (Denmark)

Olsen, Christian Adam

2010-01-01

Peptidomimetic oligomers and foldamers have received considerable attention for over a decade, with beta-peptides and the so-called peptoids (N-alkylglycine oligomers) representing prominent examples of such architectures. Lately, hybrid or mixed backbones consisting of both alpha- and beta......-amino acids (alpha/beta-peptides) have been investigated in some detail as well. The present Minireview is a survey of the literature concerning hybrid structures of alpha-amino acids and peptoids, including beta-peptoids (N-alkyl-beta-alanine oligomers), and is intended to give an overview of this area...

1/12-Scale mixing interface visualization and buoyant particle release tests in support of Tank 241-SY-101 hydrogen mitigation

Energy Technology Data Exchange (ETDEWEB)

Eschbach, E.J.; Enderlin, C.W.

1993-10-01

In support of tank waste safety programs, visualization tests were performed in the 1/12-scale tank facility, using a low-viscosity simulant. The primary objective of the tests was to obtain video records of the transient jet-sludge interaction. The intent is that these videos will provide useful qualitative data for comparison with model predictions. Two tests were initially planned: mixing interface visualization (MIV) and buoyant particle release (BPR). Completion of the buoyant particle release test was set aside in order to complete additional MIV tests. Rheological measurements were made on simulant samples before testing, and the simulant was found to exhibit thixotropic behavior. Shear vane measurements were also made on an in-situ analog of the 1/12-scale tank simulant. Simulant shear strength has been observed to be time dependent. The primary objective of obtaining video records of jet-sludge interaction was satisfied, and the records yielded jet location information which may be of use in completing model comparisons. The modeling effort is not part of this task, but this report also discusses test specific instrumentation, visualization techniques, and shear vane instrumentation which would enable improved characterization of jet-sludge interaction and simulant characteristics.

1/12-Scale mixing interface visualization and buoyant particle release tests in support of Tank 241-SY-101 hydrogen mitigation

International Nuclear Information System (INIS)

Eschbach, E.J.; Enderlin, C.W.

1993-10-01

In support of tank waste safety programs, visualization tests were performed in the 1/12-scale tank facility, using a low-viscosity simulant. The primary objective of the tests was to obtain video records of the transient jet-sludge interaction. The intent is that these videos will provide useful qualitative data for comparison with model predictions. Two tests were initially planned: mixing interface visualization (MIV) and buoyant particle release (BPR). Completion of the buoyant particle release test was set aside in order to complete additional MIV tests. Rheological measurements were made on simulant samples before testing, and the simulant was found to exhibit thixotropic behavior. Shear vane measurements were also made on an in-situ analog of the 1/12-scale tank simulant. Simulant shear strength has been observed to be time dependent. The primary objective of obtaining video records of jet-sludge interaction was satisfied, and the records yielded jet location information which may be of use in completing model comparisons. The modeling effort is not part of this task, but this report also discusses test specific instrumentation, visualization techniques, and shear vane instrumentation which would enable improved characterization of jet-sludge interaction and simulant characteristics

Influence of steam leakage through vane, gland, and shaft seals on rotordynamics of high-pressure rotor of a 1,000 MW ultra-supercritical steam turbine

Energy Technology Data Exchange (ETDEWEB)

Jiang, P.N. [Shanghai Jiao Tong University, Key Laboratory of Power Machinery and Engineering, Ministry of Education, School of Mechanical Engineering, Shanghai (China); Shanghai Turbine Company, Department of R and D, Shanghai (China); Wang, W.Z.; Liu, Y.Z. [Shanghai Jiao Tong University, Key Laboratory of Power Machinery and Engineering, Ministry of Education, School of Mechanical Engineering, Shanghai (China); Meng, G. [Shanghai Jiao Tong University, State Key Laboratory of Mechanical System and Vibration, School of Mechanical Engineering, Shanghai (China)

2012-02-15

A comparative analysis of the influence of steam leakage through vane, gland, and shaft seals on the rotordynamics of the high-pressure rotor of a 1,000 MW ultra-supercritical steam turbine was performed using numerical calculations. The rotordynamic coefficients associated with steam leakage through the three labyrinth seals were calculated using the control-volume method and perturbation analysis. A stability analysis of the rotor system subject to the steam forcing induced by the leakage flow was performed using the finite element method. An analysis of the influence of the labyrinth seal forcing on the rotordynamics was carried out by varying the geometrical parameters pertaining to the tooth number, seal clearance, and inner diameter of the labyrinth seals, along with the thermal parameters with respect to pressures and temperatures. The results demonstrated that the steam forcing with an increase in the length of the blade for the vane seal significantly influences the rotordynamic coefficients. Furthermore, the contribution of steam forcing to the instability of the rotor is decreased and increased with increases in the seal clearance and tooth number, respectively. The comparison of the rotordynamic coefficients associated with steam leakage through the vane seal, gland seal, and shaft seal convincingly disclosed that, although the steam forcing attenuates the stability of the rotor system, the steam turbine is still operating under safe conditions. (orig.)

Stochastic Reachability Analysis of Hybrid Systems

CERN Document Server

Bujorianu, Luminita Manuela

2012-01-01

Stochastic reachability analysis (SRA) is a method of analyzing the behavior of control systems which mix discrete and continuous dynamics. For probabilistic discrete systems it has been shown to be a practical verification method but for stochastic hybrid systems it can be rather more. As a verification technique SRA can assess the safety and performance of, for example, autonomous systems, robot and aircraft path planning and multi-agent coordination but it can also be used for the adaptive control of such systems. Stochastic Reachability Analysis of Hybrid Systems is a self-contained and accessible introduction to this novel topic in the analysis and development of stochastic hybrid systems. Beginning with the relevant aspects of Markov models and introducing stochastic hybrid systems, the book then moves on to coverage of reachability analysis for stochastic hybrid systems. Following this build up, the core of the text first formally defines the concept of reachability in the stochastic framework and then...

Hybrid preheat/recirculating steam generator

International Nuclear Information System (INIS)

Lilly, G.P.

1985-01-01

The patent describes a hybrid preheat/recirculating steam generator for nuclear power plants. The steam generator utilizes recirculated liquid to preheat incoming liquid. In addition, the steam generator incorporates a divider so as to limit the amount of recirculating water mixed with the feedwater. (U.K.)

Masses of open-flavour heavy-light hybrids from QCD sum-rules

Energy Technology Data Exchange (ETDEWEB)

Ho, J. [Department of Physics and Engineering Physics, University of Saskatchewan,Saskatoon, SK, S7N 5E2 (Canada); Harnett, D. [Department of Physics, University of the Fraser Valley,Abbotsford, BC, V2S 7M8 (Canada); Steele, T.G. [Department of Physics and Engineering Physics, University of Saskatchewan,Saskatoon, SK, S7N 5E2 (Canada)

2017-05-29

We use QCD Laplace sum-rules to predict masses of open-flavour heavy-light hybrids where one of the hybrid’s constituent quarks is a charm or bottom and the other is an up, down, or strange. We compute leading-order, diagonal correlation functions of several hybrid interpolating currents, taking into account QCD condensates up to dimension-six, and extract hybrid mass predictions for all J{sup P}∈{0"±, 1"±}, as well as explore possible mixing effects with conventional quark-antiquark mesons. Within theoretical uncertainties, our results are consistent with a degeneracy between the heavy-nonstrange and heavy-strange hybrids in all J{sup P} channels. We find a similar mass hierarchy of 1{sup +}, 1{sup −}, and 0{sup +} states (a 1{sup +} state lighter than essentially degenerate 1{sup −} and 0{sup +} states) in both the charm and bottom sectors, and discuss an interpretation for the 0{sup −} states. If conventional meson mixing is present the effect is an increase in the hybrid mass prediction, and we estimate an upper bound on this effect.

Mixed bi-material electrodes based on LiMn2O4 and activated carbon for hybrid electrochemical energy storage devices

International Nuclear Information System (INIS)

Cericola, Dario; Novak, Petr; Wokaun, Alexander; Koetz, Ruediger

2011-01-01

Highlights: → Bi-material electrodes for electrochemical hybrid devices were characterized. → Bi-material electrodes have higher specific charge than capacitor electrodes. → Bi-material electrodes have better rate capability than battery electrodes. → Bi-material systems outperform batteries and capacitors in pulsed applications. - Abstract: The performance of mixed bi-material electrodes composed of the battery material, LiMn 2 O 4 , and the electrochemical capacitor material, activated carbon, for hybrid electrochemical energy storage devices is investigated by galvanostatic charge/discharge and pulsed discharge experiments. Both, a high and a low conductivity lithium-containing electrolyte are used. The specific charge of the bi-material electrode is the linear combination of the specific charges of LiMn 2 O 4 and activated carbon according to the electrode composition at low discharge rates. Thus, the specific charge of the bi-material electrode falls between the specific charge of the activated carbon electrode and the LiMn 2 O 4 battery electrode. The bi-material electrodes have better rate capability than the LiMn 2 O 4 battery electrode. For high current pulsed applications the bi-material electrodes typically outperform both the battery and the capacitor electrode.

导叶对涡轮型垂直轴风力机气动性能的影响%Effects of guiding vanes on aerodynamic performance of vortex vertical axis wind turbine

Institute of Scientific and Technical Information of China (English)

原红红; 赵振宙; 郑源; 黄娟

2013-01-01

To overcome the problem of low efficiency of the traditional vertical axis wind turbine, the structural advantages of the wind turbine with guiding vanes are introduced and the effects of guiding vanes on the vortex vertical axis wind turbine are analyzed in detail. Based on computational fluid dynamics theory, the slippage mesh technique and the k-ε model were used to compare the aerodynamic performance of the vortex vertical axis wind turbine with and without guiding vanes at a design velocity of 12 m/s. Studies have shown that the guiding vanes can effectively prevent the direct impact of the coming flow from acting on the suction section of the blade in the upwind area so as to decrease the drag torque, while the guiding vanes also negatively affect the performance of blades in the downwind area, but the positive effect of the former is more significant, so the performance of a wind turbine with guiding vanes greatly improves. The vortex vertical axis wind turbine with arc-type guiding vanes has a wider operating range, higher optimum tip speed ratio, and higher aerodynamic efficiency. The maximum wind power coefficient can reach 0.24 .%针对传统垂直轴风力机效率低的缺陷,阐述带导叶垂直轴风力机的结构优势,并分析导叶对涡轮型垂直轴风力机的作用。应用计算流体力学理论,在设计风速12 m/s下,采用滑移网格技术及k-着模型对有、无导叶两种涡轮型垂直轴风力机的气动性能进行比较。研究表明,导叶可以有效降低由于来流对逆风区叶片吸力面的直接冲击而造成的阻力扭矩,也会负面影响顺风区叶片的性能,但其负作用效果远不及在逆风区挡流降阻的正作用效果,故加导叶后风轮的性能会有很大提高。带弧线形导叶涡轮型垂直轴风力机最大风能利用系数可达0.24,具有工作范围广、最佳尖速比大的特点。

Tubular-Type Hydroturbine Performance for Variable Guide Vane Opening by CFD

Science.gov (United States)

Kim, Y. T.; Nam, S. H.; Cho, Y. J.; Hwang, Y. C.; Choi, Y. D.; Nam, C. D.; Lee, Y. H.

Micro hydraulic power generation which has output of less or equal to 100kW is attracting considerable attention. This is because of its small, simple, renewable, and large amount of energy resources. By using a small hydro power generator of which main concept is based on using differential water pressures in pipe lines, energy which was initially wasted by use of a reducing valve at an end of the pipeline, is collected by a turbine in the hydro power generator. A propeller shaped hydroturbine has been used in order to make use of this renewable pressure energy. In this study, in order to acquire basic design data of tubular type hydroturbine, output power, head, and efficiency characteristics due to the guide vane opening angle are examined in detail. Moreover, influences of pressure, tangential and axial velocity distributions on turbine performance are investigated by using a commercial CFD code.

CFD method research on characteristics cells in rod bundle fuel assembly

International Nuclear Information System (INIS)

Chen Jie; Chen Bingyan; Zhang Hong

2011-01-01

Two characteristic cells are in AFA-3G fuel assembly, that is typical cell and control rod guide cell. And there are some rules on the arrangement of mixing vanes. For the two characteristic cells, mixing capability is evaluated axially from the point of the first and second kind of sub-channel with CFD method. Mass mixing and heat mixing are interaction but different with each other. Although the mass mixing in the first kind of sub-channel is stronger, the thermal capability of the two is to some tune from the point of heat transfer. In the experiment research on thermal-hydraulic performance of AFA-3G fuel assembly, the arrangements of mixing vanes should refer to the two spacer grids of characteristic cells. (authors)

Enhancement of nuclear heat transfer in a typical pressurized water reactor by new spacer grids

International Nuclear Information System (INIS)

Nazifi, M.; Nematollahi, M.

2007-01-01

The fuel element geometry typically used in nuclear reactor is rod bundle whose rod-to-rod clearance is maintained by grid spacer. The heat generated in the rod by nuclear reaction is removed by coolant, usually in turbulent flow. The coolant moves axially through the subchannels. Fuel spacer grid affects the coolant flow distribution in a fuel rod bundle, and so spacer geometry has a strong influence on a bundle's thermal-hydraulic characteristics such as critical heat flux and pressure drop. An understanding of the detailed structure of the turbulent flow and heat transfer in the rod bundle, used especially as nuclear fuel elements, is of major interest to the nuclear power industry for their safe and reliable operation. The flow mixing devices on grid spacer would enhance the mixing rate between sub-channels and promote the turbulence in subchannel. The present study evaluates the effects of mixing vane shape on flow structure and heat transfer downstream of mixing vane in a sub-channel of fuel assembly, by obtaining velocity and pressure fields, turbulent intensity, flow mixing factors, heat transfer coefficient and friction factor using three-dimensional RANS analysis. Six new shapes mixing vane designed by the authors, are simulated numerically to evaluate the performance in enhancing the heat transfer, in comparison with commercialized split vane. Standard K-epsilon model are used as a turbulence closure model and periodic and symmetry condition are set as boundary conditions. The capability of the model to predict the coolant flow distribution inside rod bundles is shown and discussed on the base of comparison with experimental data for a variety of geometrical and Reynolds number conditions. It is conformed that the turbulence in the sub-channel was significantly promoted by spacer and mixing devices but rapidly decreased to a fully developed level approximately 10 time of hydraulic diameter downstream of the top of spacer. Ring type mixer showed a high

Human mixed infections of Leishmania spp. and Leishmania-Trypanosoma cruzi in a sub Andean Bolivian area: identification by polymerase chain reaction/hybridization and isoenzyme

Directory of Open Access Journals (Sweden)

B Bastrenta

2003-03-01

Full Text Available Parasites belonging to Leishmania braziliensis, Leishmania donovani, Leishmania mexicana complexes and Trypanosoma cruzi (clones 20 and 39 were searched in blood, lesions and strains collected from 28 patients with active cutaneous leishmaniasis and one patient with visceral leishmaniasis. PCR-hybridization with specific probes of Leishmania complexes (L. braziliensis, L. donovani and L. mexicana and T. cruzi clones was applied to the different DNA samples. Over 29 patients, 8 (27.6% presented a mixed infection Leishmania complex species, 17 (58.6% a mixed infection Leishmania-T. cruzi, and 4 (13.8% a multi Leishmania-T. cruzi infection. Several patients were infected by the two Bolivian major clones 20 and 39 of T. cruzi (44.8%. The L. braziliensis complex was more frequently detected in lesions than in blood and a reverse result was observed for L. mexicana complex. The polymerase chain reaction-hybridization design offers new arguments supporting the idea of an underestimated rate of visceral leishmanisis in Bolivia. Parasites were isolated by culture from the blood of two patients and lesions of 10 patients. The UPGMA (unweighted pair-group method with arithmetic averages dendrogram computed from Jaccard's distances obtained from 11 isoenzyme loci data confirmed the presence of the three Leishmania complexes and undoubtedly identified human infections by L. (V. braziliensis, L. (L. chagasi and L. (L. mexicana species. Additional evidence of parasite mixtures was visualized through mixed isoenzyme profiles, L. (V. braziliensis-L. (L. mexicana and Leishmania spp.-T. cruzi.The epidemiological profile in the studied area appeared more complex than currently known. This is the first report of parasitological evidence of Bolivian patients with trypanosomatidae multi infections and consequences on the diseases' control and patient treatments are discussed.

Formation of Intermediate Plutonic Rocks by Magma Mixing: the Shoshonite Suite of Timna, Southern Israel.

Science.gov (United States)

Fox, S.; Katzir, Y.

2017-12-01

In magmatic series considered to form by crystal fractionation intermediate rocks are usually much less abundant than expected. Yet, intermediate plutonic rocks, predominantly monzodiorites, are very abundant in the Neoproterozoic Timna igneous complex, S. Israel. A previously unnoticed plutonic shoshonitic suite was recently defined and mapped in Timna (Litvinovsky et al., 2015). It mostly comprises intermediate rocks in a seemingly 'continuous' trend from monzodiorite through monzonite to quartz syenite. Macroscale textures including gradational boundaries of mafic and felsic rocks and MME suggest that magma mixing is central in forming intermediate rocks in Timna. Our petrographic, microtextural and mineral chemistry study delineates the mode of incipient mixing, ultimate mingling and crystal equilibration in hybrid melts. An EMP study of plagioclase from rocks across the suite provides a quantitative evaluation of textures indicative of magma mixing/mingling, including recurrent/patchy zoning, Ca spike, boxy/sponge cellular texture and anti-Rapakivi texture. Each texture has an affinity to a particular mixing region. A modal count of these textures leads to a kinetic mixing model involving multi temporal and spatial scales necessary to form the hybrid intermediate rocks. A `shell'-like model for varying degrees of mixing is developed with the more intensive mixing at the core and more abundant felsic and mafic end-members towards the outer layer. REE patterns in zircon shows that it originated from both mafic and felsic parent melts. Whole rock Fe vs Sr plot suggests a two-stage mixing between the monzogabbro and quartz-syenite producing first mesocratic syenite, and subsequent mixing with a fractionating monzogabbro resulting in monzonitic compositions. A fractionating monzogabbro intruded into a syenitic melt sequentially. While slowly cooling, the monzogabbro heated the immediate syenitic melt, lowering the viscosity and rheological obstruction to overturn

Structural tunability and switchable exciton emission in inorganic-organic hybrids with mixed halides

Science.gov (United States)

Ahmad, Shahab; Baumberg, Jeremy J.; Vijaya Prakash, G.

2013-12-01

Room-temperature tunable excitonic photoluminescence is demonstrated in alloy-tuned layered Inorganic-Organic (IO) hybrids, (C12H25NH3)2PbI4(1-y)Br4y (y = 0 to 1). These perovskite IO hybrids adopt structures with alternating stacks of low-dimensional inorganic and organic layers, considered to be naturally self-assembled multiple quantum wells. These systems resemble stacked monolayer 2D semiconductors since no interlayer coupling exists. Thin films of IO hybrids exhibit sharp and strong photoluminescence (PL) at room-temperature due to stable excitons formed within the low-dimensional inorganic layers. Systematic variation in the observed exciton PL from 510 nm to 350 nm as the alloy composition is changed, is attributed to the structural readjustment of crystal packing upon increase of the Br content in the Pb-I inorganic network. The energy separation between exciton absorption and PL is attributed to the modified exciton density of states and diffusion of excitons from relatively higher energy states corresponding to bromine rich sites towards the lower energy iodine sites. Apart from compositional fluctuations, these excitons show remarkable reversible flips at temperature-induced phase transitions. All the results are successfully correlated with thermal and structural studies. Such structural engineering flexibility in these hybrids allows selective tuning of desirable exciton properties within suitable operating temperature ranges. Such wide-range PL tunability and reversible exciton switching in these novel IO hybrids paves the way to potential applications in new generation of optoelectronic devices.

Hybrid mesons: old prejudices and new spectroscopy

International Nuclear Information System (INIS)

Kalashnikova, Yu.S.

1997-01-01

The models for hybrid mesons are discussed, in which the gluonic excitations manifest themselves as the vibrations of the quark-antiquark QCD string. The predictions for the spectra, decays and mixing with hadronic channels are presented. (orig.)

CFD simulations to study the effects of wall protrusions on microfluidic mixing

Science.gov (United States)

Sarkar, Sourav; Singh, K. K.; Shankar, V.; Shenoy, K. T.

2015-08-01

In this study the effects of different types of wall protrusions on microfluidic mixing are studied using computational fluid dynamics (CFD) simulations. Two new protrusions, single first bracket protrusions and double opposite first bracket protrusions (DOFBPs), are conceptualized, evaluated through CFD simulations and compared to protrusions having standard geometrical shapes, e.g. rectangular protrusions, triangular protrusions and semicircular protrusions. In the range of Reynolds numbers covered in this study, the microchannel having an opposed T-junction and DOFBPs is found to provide good mixing. A hybrid approach relying on the modification of microfluidic junctions as well as wall protrusions for enhancing microfluidic mixing is also evaluated. The microchannel based on the hybrid approach of an OA 10°-20°-165° WY-junction and DOFBPs is also found to provide very good mixing for a wide range of Reynolds numbers.

Hybrid and Blended Learning: Modifying Pedagogy across Path, Pace, Time, and Place

Science.gov (United States)

O'Byrne, W. Ian; Pytash, Kristine E.

2015-01-01

Hybrid or blended learning is defined as a pedagogical approach that includes a combination of face-to-face instruction with computer-mediated instruction. The terms "blended learning", "hybrid learning", and "mixed-mode learning" are used interchangeably in current research; however, in the United States,…

System equivalent model mixing

Science.gov (United States)

Klaassen, Steven W. B.; van der Seijs, Maarten V.; de Klerk, Dennis

2018-05-01

This paper introduces SEMM: a method based on Frequency Based Substructuring (FBS) techniques that enables the construction of hybrid dynamic models. With System Equivalent Model Mixing (SEMM) frequency based models, either of numerical or experimental nature, can be mixed to form a hybrid model. This model follows the dynamic behaviour of a predefined weighted master model. A large variety of applications can be thought of, such as the DoF-space expansion of relatively small experimental models using numerical models, or the blending of different models in the frequency spectrum. SEMM is outlined, both mathematically and conceptually, based on a notation commonly used in FBS. A critical physical interpretation of the theory is provided next, along with a comparison to similar techniques; namely DoF expansion techniques. SEMM's concept is further illustrated by means of a numerical example. It will become apparent that the basic method of SEMM has some shortcomings which warrant a few extensions to the method. One of the main applications is tested in a practical case, performed on a validated benchmark structure; it will emphasize the practicality of the method.

Achieving more efficient operation of the nozzle vane and rotor blade rows of gas turbines through using nonaxisymmetric end wall surfaces of interblade channels

Science.gov (United States)

Inozemtsev, A. A.; Samokhvalov, N. Yu.; Tikhonov, A. S.

2012-09-01

Results from a numerical study of three versions of the end-wall generatrix of the interblade channel used in the second-stage nozzle vanes of a prospective engine's turbine are presented. Recommendations for designing nonaxisymmetric end-wall surfaces are suggested based on the obtained data.

Euro hybrid materials and structures. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Hausmann, Joachim M.; Siebert, Marc (eds.)

2016-08-01

In order to use the materials as best as possible, several different materials are usually mixed in one component, especially in the field of lightweight design. If these combinations of materials are joined inherently, they are called multi material design products or hybrid structures. These place special requirements on joining technology, design methods and manufacturing and are challenging in other aspects, too. The eight chapters with manuscripts of the presentations are: Chapter 1- Interface: What happens in the interface between the two materials? Chapter 2 - Corrosion and Residual Stresses: How about galvanic corrosion and thermal residual stresses in the contact zone of different materials? Chapter 3 - Characterization: How to characterize and test hybrid materials? Chapter 4 - Design: What is a suitable design and dimensioning method for hybrid structures? Chapter 5 - Machining and Processing: How to machine and process hybrid structures and materials? Chapter 6 - Component Manufacturing: What is a suitable manufacturing route for hybrid structures? Chapter 7 - Non-Destructive Testing and Quality Assurance: How to assure the quality of material and structures? Chapter 8 - Joining: How to join components of different materials?.

Euro hybrid materials and structures. Proceedings

International Nuclear Information System (INIS)

Hausmann, Joachim M.; Siebert, Marc

2016-01-01

In order to use the materials as best as possible, several different materials are usually mixed in one component, especially in the field of lightweight design. If these combinations of materials are joined inherently, they are called multi material design products or hybrid structures. These place special requirements on joining technology, design methods and manufacturing and are challenging in other aspects, too. The eight chapters with manuscripts of the presentations are: Chapter 1- Interface: What happens in the interface between the two materials? Chapter 2 - Corrosion and Residual Stresses: How about galvanic corrosion and thermal residual stresses in the contact zone of different materials? Chapter 3 - Characterization: How to characterize and test hybrid materials? Chapter 4 - Design: What is a suitable design and dimensioning method for hybrid structures? Chapter 5 - Machining and Processing: How to machine and process hybrid structures and materials? Chapter 6 - Component Manufacturing: What is a suitable manufacturing route for hybrid structures? Chapter 7 - Non-Destructive Testing and Quality Assurance: How to assure the quality of material and structures? Chapter 8 - Joining: How to join components of different materials?

StackInsights: Cognitive Learning for Hybrid Cloud Readiness

OpenAIRE

Qiao, Mu; Bathen, Luis; Génot, Simon-Pierre; Lee, Sunhwan; Routray, Ramani

2017-01-01

Hybrid cloud is an integrated cloud computing environment utilizing a mix of public cloud, private cloud, and on-premise traditional IT infrastructures. Workload awareness, defined as a detailed full range understanding of each individual workload, is essential in implementing the hybrid cloud. While it is critical to perform an accurate analysis to determine which workloads are appropriate for on-premise deployment versus which workloads can be migrated to a cloud off-premise, the assessment...

An Integrating Framework for Mixed Systems

Science.gov (United States)

Coutrix, Céline; Nigay, Laurence

Technological advances in hardware manufacturing led to an extended range of possibilities for designing physical-digital objects involved in a mixed system. Mixed systems can take various forms and include augmented reality, augmented virtuality, and tangible systems. In this very dynamic context, it is difficult to compare existing mixed systems and to systematically explore the design space. Addressing this design problem, this chapter presents a unified point of view on mixed systems by focusing on mixed objects involved in interaction, i.e., hybrid physical-digital objects straddling physical and digital worlds. Our integrating framework is made of two complementary facets of a mixed object: we define intrinsic as well as extrinsic characteristics of an object by considering its role in the interaction. Such characteristics of an object are useful for comparing existing mixed systems at a fine-grain level. The taxonomic power of these characteristics is discussed in the context of existing mixed systems from the literature. Their generative power is illustrated by considering a system, Roam, which we designed and developed.

Identification of a novel interspecific hybrid yeast from a metagenomic spontaneously inoculated beer sample using Hi-C.

Science.gov (United States)

Smukowski Heil, Caiti; Burton, Joshua N; Liachko, Ivan; Friedrich, Anne; Hanson, Noah A; Morris, Cody L; Schacherer, Joseph; Shendure, Jay; Thomas, James H; Dunham, Maitreya J

2018-01-01

Interspecific hybridization is a common mechanism enabling genetic diversification and adaptation; however, the detection of hybrid species has been quite difficult. The identification of microbial hybrids is made even more complicated, as most environmental microbes are resistant to culturing and must be studied in their native mixed communities. We have previously adapted the chromosome conformation capture method Hi-C to the assembly of genomes from mixed populations. Here, we show the method's application in assembling genomes directly from an uncultured, mixed population from a spontaneously inoculated beer sample. Our assembly method has enabled us to de-convolute four bacterial and four yeast genomes from this sample, including a putative yeast hybrid. Downstream isolation and analysis of this hybrid confirmed its genome to consist of Pichia membranifaciens and that of another related, but undescribed, yeast. Our work shows that Hi-C-based metagenomic methods can overcome the limitation of traditional sequencing methods in studying complex mixtures of genomes. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Structural tunability and switchable exciton emission in inorganic-organic hybrids with mixed halides

International Nuclear Information System (INIS)

Ahmad, Shahab; Vijaya Prakash, G.; Baumberg, Jeremy J.

2013-01-01

Room-temperature tunable excitonic photoluminescence is demonstrated in alloy-tuned layered Inorganic-Organic (IO) hybrids, (C 12 H 25 NH 3 ) 2 PbI 4(1−y) Br 4y (y = 0 to 1). These perovskite IO hybrids adopt structures with alternating stacks of low-dimensional inorganic and organic layers, considered to be naturally self-assembled multiple quantum wells. These systems resemble stacked monolayer 2D semiconductors since no interlayer coupling exists. Thin films of IO hybrids exhibit sharp and strong photoluminescence (PL) at room-temperature due to stable excitons formed within the low-dimensional inorganic layers. Systematic variation in the observed exciton PL from 510 nm to 350 nm as the alloy composition is changed, is attributed to the structural readjustment of crystal packing upon increase of the Br content in the Pb-I inorganic network. The energy separation between exciton absorption and PL is attributed to the modified exciton density of states and diffusion of excitons from relatively higher energy states corresponding to bromine rich sites towards the lower energy iodine sites. Apart from compositional fluctuations, these excitons show remarkable reversible flips at temperature-induced phase transitions. All the results are successfully correlated with thermal and structural studies. Such structural engineering flexibility in these hybrids allows selective tuning of desirable exciton properties within suitable operating temperature ranges. Such wide-range PL tunability and reversible exciton switching in these novel IO hybrids paves the way to potential applications in new generation of optoelectronic devices

Analysis of product efficiency of hybrid vehicles and promotion policies

International Nuclear Information System (INIS)

Choi, Hyundo; Oh, Inha

2010-01-01

The key aim of this study is to evaluate the product efficiency of current hybrid vehicles and suggest effective policies to promote hybrid vehicles in the Korean automobile market and development trends of hybrid vehicles. The efficiency levels for car models sold in Korea, including hybrid ones, were measured using the recently developed discrete additive data envelopment analysis (DEA) model that reflects consumer preference. The result of the analysis shows that current hybrid vehicles on the market are still at lower competitive advantage than traditional car models with conventional combustion engines and we can suggest a mix of incentive policies to promote the competitiveness of hybrid vehicles. In addition, we also identify two distinctive trends of hybrid vehicle development: environment-oriented hybrid vehicles and performance-oriented hybrid vehicles. It implies that the government should take account of development trends of hybrid vehicles to achieve the policy goals in designing support schemes and automobile companies that are willing to develop hybrid vehicles can also gain some insights for making strategic decisions. (author)

Multiplicity within Singularity: Racial Categorization and Recognizing “Mixed Race” in Singapore

Directory of Open Access Journals (Sweden)

Zarine L. Rocha

2011-01-01

Full Text Available “Race” and racial categories play a significant role in everyday life and state organization in Singapore. While multiplicity and diversity are important characteristics of Singaporean society, Singapore’s multiracial ideology is firmly based on separate, racialized groups, leaving little room for racial projects reflecting more complex identifications. This article explores national narratives of race, culture and belonging as they have developed over time, used as a tool for the state, and re-emerging in discourses of hybridity and “double-barrelled” racial identifications. Multiracialism, as a maintained structural feature of Singaporean society, is both challenged and reinforced by new understandings of hybridity and older conceptions of what it means to be “mixed race” in a (post-colonial society. Tracing the temporal thread of racial categorization through a lens of mixedness, this article places the Singaporean case within emerging work on hybridity and recognition of “mixed race”. It illustrates how state-led understandings of race and “mixed race” describe processes of both continuity and change, with far-reaching practical and ideological impacts.

Hybrid, Nanoscale Phospholipid/Block Copolymer Vesicles

Directory of Open Access Journals (Sweden)

Bo Liedberg

2013-09-01

Full Text Available Hybrid phospholipid/block copolymer vesicles, in which the polymeric membrane is blended with phospholipids, display interesting self-assembly behavior, incorporating the robustness and chemical versatility of polymersomes with the softness and biocompatibility of liposomes. Such structures can be conveniently characterized by preparing giant unilamellar vesicles (GUVs via electroformation. Here, we are interested in exploring the self-assembly and properties of the analogous nanoscale hybrid vesicles (ca. 100 nm in diameter of the same composition prepared by film-hydration and extrusion. We show that the self-assembly and content-release behavior of nanoscale polybutadiene-b-poly(ethylene oxide (PB-PEO/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC hybrid phospholipid/block copolymer vesicles can be tuned by the mixing ratio of the amphiphiles. In brief, these hybrids may provide alternative tools for drug delivery purposes and molecular imaging/sensing applications and clearly open up new avenues for further investigation.

Ambipolar solution-processed hybrid perovskite phototransistors

KAUST Repository

Li, Feng

2015-09-08

Organolead halide perovskites have attracted substantial attention because of their excellent physical properties, which enable them to serve as the active material in emerging hybrid solid-state solar cells. Here we investigate the phototransistors based on hybrid perovskite films and provide direct evidence for their superior carrier transport property with ambipolar characteristics. The field-effect mobilities for triiodide perovskites at room temperature are measured as 0.18 (0.17) cm2 V−1 s−1 for holes (electrons), which increase to 1.24 (1.01) cm2 V−1 s−1 for mixed-halide perovskites. The photoresponsivity of our hybrid perovskite devices reaches 320 A W−1, which is among the largest values reported for phototransistors. Importantly, the phototransistors exhibit an ultrafast photoresponse speed of less than 10 μs. The solution-based process and excellent device performance strongly underscore hybrid perovskites as promising material candidates for photoelectronic applications.

Hierarchically porous carbon/polyaniline hybrid for use in supercapacitors.

Science.gov (United States)

Joo, Min Jae; Yun, Young Soo; Jin, Hyoung-Joon

2014-12-01

A hierarchically porous carbon (HPC)/polyaniline (PANI) hybrid electrode was prepared by the polymerization of PANI on the surface of the HPC via rapid-mixing polymerization. The surface morphologies and chemical composition of the HPC/PANI hybrid electrode were characterized using transmission electron microscopy and X-ray photoelectron spectroscopy (XPS), respectively. The surface morphologies and XPS results for the HPC, PANI and HPC/PANI hybrids indicate that PANI is coated on the surface of HPC in the HPC/PANI hybrids which have two different nitrogen groups as a benzenoid amine (-NH-) peak and positively charged nitrogen (N+) peak. The electrochemical performances of the HPC/PANI hybrids were analyzed by performing cyclic voltammetry and galvanostatic charge-discharge tests. The HPC/PANI hybrids showed a better specific capacitance (222 F/g) than HPC (111 F/g) because of effect of pseudocapacitor behavior. In addition, good cycle stabilities were maintained over 1000 cycles.

Magma hybridization in the Western Tatra Mts. granitoid intrusion (S-Poland, Western Carpathians).

Science.gov (United States)

Burda, Jolanta; Gawęda, Aleksandra; Klötzli, Urs

In the Variscan Western Tatra granites hybridization phenomena such as mixing and mingling can be observed at the contact of mafic precursors of dioritic composition and more felsic granitic host rocks. The textural evidence of hybridization include: plagioclase-K-feldspar-sphene ocelli, hornblende- and biotite-rimmed quartz ocelli, plagioclase with Ca-rich spike zonation, inversely zoned K-feldspar crystals, mafic clots, poikilitic plagioclase and quartz crystals, mixed apatite morphologies, zoned K-feldspar phenocrysts. The apparent pressure range of the magma hybridization event was calculated at 6.1 kbar to 4.6 kbar, while the temperature, calculated by independent methods, is in the range of 810°C-770°C. U-Pb age data of the hybrid rocks were obtained by in-situ LA-MC-ICP-MS analysis of zircon. The oscillatory zoned zircon crystals yield a concordia age of 368 ± 8 Ma (MSWD = 1.1), interpreted as the age of magma hybridization and timing of formation of the magmatic precursors. It is the oldest Variscan magmatic event in that part of the Tatra Mountains.

The experimental study on the wind turbine’s guide-vanes and diffuser of an exhaust air energy recovery system integrated with the cooling tower

International Nuclear Information System (INIS)

Chong, W.T.; Hew, W.P.; Yip, S.Y.; Fazlizan, A.; Poh, S.C.; Tan, C.J.; Ong, H.C.

2014-01-01

Highlights: • On-site exhaust air energy recovery turbine generator mounted above cooling tower. • Energy from wasted wind resources is re-used for electricity generation. • Optimum angle arrangement of guide-vanes and diffusers help to improve wind-flow. • Enclosure solves conventional wind turbine problems. • 13.3% reduction in CO 2 emission is expected to be achieved from this system. - Abstract: An assembly of two vertical axis wind turbines (VAWTs) and an enclosure is installed above a cooling tower to harness the discharged wind for electricity generation. The enclosure consists of guide-vanes and diffuser-plates, is used to enhance the rotational speed of the turbines for power augmentation. The angle of the guide-vanes is optimized to ensure the oncoming wind stream impinges the rotor blades of the turbine at an optimum angle. The diffuser-plates are tilted at an optimum angle to increase the discharged airflow rate. The performance of the system is tested in the laboratory followed by a field test on an actual size cooling tower. The VAWT performance is increased in the range of 7–8% with the integration of enclosure. There is no significant difference in the current consumption of the fan motor between the bare cooling tower and the one with installed VAWTs. With the presence of this system, approximately 17.5 GW h/year is expected to be recovered from 3000 units of cooling towers at commercial areas, assuming the cooling tower is driven by a 7.5 kW fan motor and operates 16 h/day. This amount of recovered energy can also be translated into 13% reduction in CO 2 emission

Chitosan-nanosilica hybrid materials: Preparation and properties

International Nuclear Information System (INIS)

Podust, T.V.; Kulik, T.V.; Palyanytsya, B.B.; Gun’ko, V.M.; Tóth, A.; Mikhalovska, L.; Menyhárd, A.; László, K.

2014-01-01

Highlights: • Hybrid chitosan-nanosilica materials were synthesized using an adsorption modification method. • The chitosan adsorption capacity is higher on the silica/titania and silica/alumina than on the fumed silica. • Nanosilicas undergo structural and textural alterations due to modification by chitosan. • The more severe chitosan thermodestruction occurs on the silica/titania and silica/alumina surfaces than on the plain silica surface. - Abstract: The research focuses on the synthesis of novel organic–inorganic hybrid materials based on polysaccharide chitosan and nanosilicas (SiO 2 , TiO 2 /SiO 2 and Al 2 O 3 /SiO 2 ). The chitosan modified nanooxides were obtained by the equilibrium adsorption method. The chitosan adsorption capacities of silica/titania and silica/alumina are higher than of the plain silica due to the additional active sites present on the surfaces of the mixed oxides. The hybrid materials were characterized by low-temperature nitrogen adsorption/desorption, photon correlation spectroscopy (PCS), scanning electron microscopy (SEM), thermogravimetry (TG/DTG) and temperature-programmed desorption with mass spectrometry control (TPD MS) methods. The chitosan treatment only modestly influences the surface area S BET of the nanooxides but the rearrangement of the secondary and tertiary structures (aggregates and agglomerates) results in an enhancement of the mesoporosity and affects the size of the aggregates. The more severe thermodestruction of the polysaccharide desorbing from the modified mixed silicas indicates a stronger interaction between the chitosan and the mixed oxides compared to the silanol groups of the plain silica surface

Chitosan-nanosilica hybrid materials: Preparation and properties

Energy Technology Data Exchange (ETDEWEB)

Podust, T.V., E-mail: tania_list@yahoo.com [Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164 (Ukraine); Kulik, T.V., E-mail: tanyakulyk@i.ua [Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164 (Ukraine); Palyanytsya, B.B.; Gun’ko, V.M. [Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164 (Ukraine); Tóth, A. [Department of Physical Chemistry and Material Science, Budapest University of Technology and Economics, H-1521 Budapest (Hungary); Mikhalovska, L. [School of Pharmacy and Biomolecular Sciences, University of Brighton, Lewes Road, Brighton BN2 4GJ (United Kingdom); Menyhárd, A. [Department of Physical Chemistry and Material Science, Budapest University of Technology and Economics, H-1521 Budapest (Hungary); Institute of Materials Science and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences (Hungary); László, K. [Department of Physical Chemistry and Material Science, Budapest University of Technology and Economics, H-1521 Budapest (Hungary)

2014-11-30

Highlights: • Hybrid chitosan-nanosilica materials were synthesized using an adsorption modification method. • The chitosan adsorption capacity is higher on the silica/titania and silica/alumina than on the fumed silica. • Nanosilicas undergo structural and textural alterations due to modification by chitosan. • The more severe chitosan thermodestruction occurs on the silica/titania and silica/alumina surfaces than on the plain silica surface. - Abstract: The research focuses on the synthesis of novel organic–inorganic hybrid materials based on polysaccharide chitosan and nanosilicas (SiO{sub 2}, TiO{sub 2}/SiO{sub 2} and Al{sub 2}O{sub 3}/SiO{sub 2}). The chitosan modified nanooxides were obtained by the equilibrium adsorption method. The chitosan adsorption capacities of silica/titania and silica/alumina are higher than of the plain silica due to the additional active sites present on the surfaces of the mixed oxides. The hybrid materials were characterized by low-temperature nitrogen adsorption/desorption, photon correlation spectroscopy (PCS), scanning electron microscopy (SEM), thermogravimetry (TG/DTG) and temperature-programmed desorption with mass spectrometry control (TPD MS) methods. The chitosan treatment only modestly influences the surface area S{sub BET} of the nanooxides but the rearrangement of the secondary and tertiary structures (aggregates and agglomerates) results in an enhancement of the mesoporosity and affects the size of the aggregates. The more severe thermodestruction of the polysaccharide desorbing from the modified mixed silicas indicates a stronger interaction between the chitosan and the mixed oxides compared to the silanol groups of the plain silica surface.

Expanded Mixed Multiscale Finite Element Methods and Their Applications for Flows in Porous Media

KAUST Repository

Jiang, L.; Copeland, D.; Moulton, J. D.

2012-01-01

We develop a family of expanded mixed multiscale finite element methods (MsFEMs) and their hybridizations for second-order elliptic equations. This formulation expands the standard mixed multiscale finite element formulation in the sense that four

Mixed oxidizer hybrid propulsion system optimization under uncertainty using applied response surface methodology and Monte Carlo simulation

Science.gov (United States)

Whitehead, James Joshua

The analysis documented herein provides an integrated approach for the conduct of optimization under uncertainty (OUU) using Monte Carlo Simulation (MCS) techniques coupled with response surface-based methods for characterization of mixture-dependent variables. This novel methodology provides an innovative means of conducting optimization studies under uncertainty in propulsion system design. Analytic inputs are based upon empirical regression rate information obtained from design of experiments (DOE) mixture studies utilizing a mixed oxidizer hybrid rocket concept. Hybrid fuel regression rate was selected as the target response variable for optimization under uncertainty, with maximization of regression rate chosen as the driving objective. Characteristic operational conditions and propellant mixture compositions from experimental efforts conducted during previous foundational work were combined with elemental uncertainty estimates as input variables. Response surfaces for mixture-dependent variables and their associated uncertainty levels were developed using quadratic response equations incorporating single and two-factor interactions. These analysis inputs, response surface equations and associated uncertainty contributions were applied to a probabilistic MCS to develop dispersed regression rates as a function of operational and mixture input conditions within design space. Illustrative case scenarios were developed and assessed using this analytic approach including fully and partially constrained operational condition sets over all of design mixture space. In addition, optimization sets were performed across an operationally representative region in operational space and across all investigated mixture combinations. These scenarios were selected as representative examples relevant to propulsion system optimization, particularly for hybrid and solid rocket platforms. Ternary diagrams, including contour and surface plots, were developed and utilized to aid in

Impact of Spanish electricity mix, over the period 2008–2030, on the Life Cycle energy consumption and GHG emissions of Electric, Hybrid Diesel-Electric, Fuel Cell Hybrid and Diesel Bus of the Madrid Transportation System

International Nuclear Information System (INIS)

García Sánchez, Juan Antonio; López Martínez, José María; Lumbreras Martín, Julio; Flores Holgado, María Nuria; Aguilar Morales, Hansel

2013-01-01

Highlights: • We assess the performance of 4 buses that run on different alternative fuel types and technologies. • The buses assessed are Fuel Cell-Hybrid Bus, Hybrid Diesel-Electric Bus, Battery Electric Bus, and a Diesel Bus. • We examine the environmental impact caused by the Life Cycle of each vehicle technology, fossil fuel and energy carrier. • Life Cycle of Battery Electric Bus shows that it has a big potential of improvement in terms of environmental impact. - Abstract: In spite of the advanced research in automotive technology, and the improvement of fuels, the road transport sector continues to be an environmental concern, since the increase in transport demand is offsetting the effects of these technological improvements. Therefore, this poses the following question: what combination of technology and fuel is more efficient in terms of energy consumption and green house gas (GHG) emissions? To fully address this question it is necessary to carry out a Life Cycle Assessment (LCA). This paper presents a global LCA of 4 buses that run on the following fuel types and technologies: (1) Fuel Cell- Hybrid Bus, (2) Hybrid Diesel-Electric Bus (series configuration), (3) Battery Electric Bus and (4) Combustion Ignition Engine Bus. The impact categories assessed are: primary energy consumption, fossil energy and GHG emissions. Among the principal results, we can conclude that the Global LCA of buses (3) and (1) (which are the more sensitive pathways to the electricity mix variation) have for the 2008–2030 period a room for improvement of 25.62% and 28.16% in terms of efficiency of fossil energy consumption and a potential GHG emission reduction of 28.70% and 30.88% respectively

Hybrid solar cells : Perovskites under the Sun

NARCIS (Netherlands)

Loi, Maria Antonietta; Hummelen, Jan C.

2013-01-01

Mixed-halide organic–inorganic hybrid perovskites are reported to display electron–hole diffusion lengths over 1 μm. This observation provides important insight into the charge-carrier dynamics of this class of semiconductors and increases the expectations for highly efficient and cheap solar cells.

Methodological comparison on hybrid nano organic solar cell fabrication

Science.gov (United States)

Vairavan, Rajendaran; Hambali, Nor Azura Malini Ahmad; Wahid, Mohamad Halim Abd; Retnasamy, Vithyacharan; Shahimin, Mukhzeer Mohamad

2018-02-01

The development of low cost solar cells has been the main focus in recent years. This has lead to the generation of photovoltaic cells based on hybrid of nanoparticle-organic polymer materials. This type of hybrid photovoltaic cells can overcome the problem of polymeric devices having low optical absorption and carrier mobilities. The hybrid cell has the potential of bridging the efficiency gap, which in present in organic and inorganic semiconductor materials. This project focuses on obtaining an hybrid active layer consisting of nanoparticles and organic polymer, to understand the parameter involved in obtaining this active layer and finally to investigate if the addition of nano particles in to the active layer could enhance the output of the hybrid solar cell. The hybrid active layer have will be deposited using the spin coating technique by using CdTe, CdS nano particles mixed with poly (2-methoxy,5-(2-ethyl-hexyloxy)-p-phenylvinylene)MEH-PPV.

DNA hybridization sensing for cytogenetic analysis

DEFF Research Database (Denmark)

Kwasny, Dorota; Dapra, Johannes; Brøgger, Anna Line

2013-01-01

are rearrangements between two chromosome arms that results in two derivative chromosomes having a mixed DNA sequence. The current detection method is a Fluorescent In situ Hybridization, which requires a use of expensive, fluorescently labeled probes that target the DNA sequences of two chromosomes involved...... in the translocation (Kwasny et al., 2012). We have developed a new double hybridization assay that allows for sorting of the DNA chromosomal fragments into separate compartment, moreover allowing for detection of the translocation. To detect the translocation it is necessary to determine that the two DNA sequences...... forming a derivative chromosome are connected, which is achieved by two subsequent hybridization steps. The first example of the translocation detection was presented on lab-on-a-disc using fluorescently labeled DNA fragments, representing the derivative chromosome (Brøgger et al., 2012). To allow...

HYBRID EDUCATION: THE ESTIMATION IN THE CATEGORIES OF INFORMATION-AXIOLOGICAL APPROACH

Directory of Open Access Journals (Sweden)

A. S. Kizilova

2018-01-01

Full Text Available Introduction: a hybrid assessment of reality is a new information-axiological level of communication between people. The term "hybrid (hybrid training" has been used as a result of the integration of digital and communication technologies in the form of online courses.Materials and methods: the main Russian forms of education are analyzed. The evaluation of the forms of education in the categories of the information-axiological approach is made on the basis of the following idea: everything is interchangeable, since everything has value. The mixing principles and models used in the process of hybrid formation are considered. Due to the fact that any mixed training requires planning, the analysis of the project and the target group, content analysis and financial analysis in this process is carried out.Results: specific educational methods are studied at the Bauman MSTU, subject to a hybrid assessment in the categories of the information-axiological approach. The analysis showed that the above explanation of the term "hybrid formation" is extremely narrow and one-sided. In particular, the search for information on volunteer education and the search for a socially-based education was conducted not only in the Bauman MSTU, but in Russia as a whole. However, the result was the portals of international student organizations with their own projects. Another example of a different interpretation of the "hybrid education" may be the assumption of quite axiologically new duties.Discussion and Conclusions: hybrid education is not limited to any temporal and territorial framework. It can manifest itself not only in the Internet-sphere, but also in the most diverse spheres of everyday life, with the interaction of various people and entire societies.

The NTF Inlet Guide Vanes Thermal Gradient Problem and Its Mitigation

Science.gov (United States)

Venkat, Venki S.; Paryz, Roman W.; Bissett, Owen W.; Kilgore, W.

2013-01-01

The National Transonic Facility (NTF) utilizes Inlet Guide Vanes (IGV) to provide precise, quick response Mach number control for the tunnel. During cryogenic operations, the massive IGV structure can experience large thermal gradients, measured as "Delta T or (Delta)T", between the IGV ring and its support structure called the transfer case. If these temperature gradients are too large, the IGV structure can be stressed beyond its safety limit and cease operation. In recent years, (Delta)T readings exceeding the prescribed safety limits were observed frequently during cryogenic operations, particularly during model access. The tactical operation methods of the tunnel to minimize (Delta)T did not always succeed. One obvious option to remedy this condition is to warm up the IGV structure by disabling the main drive operation, but this "natural" warm up method can takes days in some cases, resulting in productivity loss. This paper documents the thermal gradient problem associated with the IGV structure during cryogenic operation and how the facility has recently achieved an acceptable mitigation which has resulted in improved efficiency of operations.

Application of dynamic slip wall modeling to a turbine nozzle guide vane

Science.gov (United States)

Bose, Sanjeeb; Talnikar, Chaitanya; Blonigan, Patrick; Wang, Qiqi

2015-11-01

Resolution of near-wall turbulent structures is computational prohibitive necessitating the need for wall-modeled large-eddy simulation approaches. Standard wall models are often based on assumptions of equilibrium boundary layers, which do not necessarily account for the dissimilarity of the momentum and thermal boundary layers. We investigate the use of the dynamic slip wall boundary condition (Bose and Moin, 2014) for the prediction of surface heat transfer on a turbine nozzle guide vane (Arts and de Rouvroit, 1992). The heat transfer coefficient is well predicted by the slip wall model, including capturing the transition to turbulence. The sensitivity of the heat transfer coefficient to the incident turbulence intensity will additionally be discussed. Lastly, the behavior of the thermal and momentum slip lengths will be contrasted between regions where the strong Reynolds analogy is invalid (near transition on the suction side) and an isothermal, zero pressure gradient flat plate boundary layer (Wu and Moin, 2010).

Effect of Hybrid Fibers on the Mechanical Properties of High Strength Concrete

Directory of Open Access Journals (Sweden)

Hamid H. Hussein, Saeed K. Rejeb Hayder T. Abd

2014-04-01

Full Text Available In this study, high strength concrete of 75 MPa compressive strength was investigated. The experimental program was designed to study the effect of fibers and hybrid fibers (steel and polypropylene fibers on the fresh (workability and wet density and hardened properties (compressive strength, splitting strength, flexural strength and dry density of high strength concrete. Results show that decreases in slump flow of all concrete mixtures containing steel, polypropylene and hybrid fibers compared with control mix (0% fiber. Hybrid high strength concrete with steel and polypropylene fibers showed superior compressive, splitting, flexural strengths over the others concrete without or with single fibers content. The test results indicate that the maximum increase in compressive and flexural strengths are obtains with the hybridization ratio (70%steel + 30% polypropylene and were equal to 14.54% and 23.34% respectively, compared with the control mix. While, the maximum increase in splitting tensile strength with (100% steel fiber + 0 polypropylene is 21.19%. 

Plasmon-modulated bistable four-wave mixing signals from a metal nanoparticle-monolayer MoS2 nanoresonator hybrid system

Science.gov (United States)

Li, Jian-Bo; Tan, Xiao-Long; Ma, Jin-Hong; Xu, Si-Qin; Kuang, Zhi-Wei; Liang, Shan; Xiao, Si; He, Meng-Dong; Kim, Nam-Chol; Luo, Jian-Hua; Chen, Li-Qun

2018-06-01

We present a study for the impact of exciton-phonon and exciton-plasmon interactions on bistable four-wave mixing (FWM) signals in a metal nanoparticle (MNP)-monolayer MoS2 nanoresonator hybrid system. Via tracing the FWM response we predict that, depending on the excitation conditions and the system parameters, such a system exhibits ‘U-shaped’ bistable FWM signals. We also map out bistability phase diagrams within the system’s parameter space. Especially, we show that compared with the exciton-phonon interaction, a strong exciton-plasmon interaction plays a dominant role in the generation of optical bistability, and the bistable region will be greatly broadened by shortening the distance between the MNP and the monolayer MoS2 nanoresonator. In the weak exciton-plasmon coupling regime, the impact of exciton-phonon interaction on optical bistability will become obvious. The scheme proposed may be used for building optical switches and logic-gate devices for optical computing and quantum information processing.

Plasmon-modulated bistable four-wave mixing signals from a metal nanoparticle-monolayer MoS2 nanoresonator hybrid system.

Science.gov (United States)

Li, Jian-Bo; Tan, Xiao-Long; Ma, Jin-Hong; Xu, Si-Qin; Kuang, Zhi-Wei; Liang, Shan; Xiao, Si; He, Meng-Dong; Kim, Nam-Chol; Luo, Jian-Hua; Chen, Li-Qun

2018-06-22

We present a study for the impact of exciton-phonon and exciton-plasmon interactions on bistable four-wave mixing (FWM) signals in a metal nanoparticle (MNP)-monolayer MoS 2 nanoresonator hybrid system. Via tracing the FWM response we predict that, depending on the excitation conditions and the system parameters, such a system exhibits 'U-shaped' bistable FWM signals. We also map out bistability phase diagrams within the system's parameter space. Especially, we show that compared with the exciton-phonon interaction, a strong exciton-plasmon interaction plays a dominant role in the generation of optical bistability, and the bistable region will be greatly broadened by shortening the distance between the MNP and the monolayer MoS 2 nanoresonator. In the weak exciton-plasmon coupling regime, the impact of exciton-phonon interaction on optical bistability will become obvious. The scheme proposed may be used for building optical switches and logic-gate devices for optical computing and quantum information processing.

Hybrid Projected Gradient-Evolutionary Search Algorithm for Mixed Integer Nonlinear Optimization Problems

National Research Council Canada - National Science Library

Homaifar, Abdollah; Esterline, Albert; Kimiaghalam, Bahram

2005-01-01

The Hybrid Projected Gradient-Evolutionary Search Algorithm (HPGES) algorithm uses a specially designed evolutionary-based global search strategy to efficiently create candidate solutions in the solution space...

Flora Robotica – Mixed Societies of Symbiotic Robot-Plant Bio-Hybrids

DEFF Research Database (Denmark)

Hamann, Heiko; Wahby, Mostafa; Schmickl, Thomas

2015-01-01

robotica. Our objective is to develop and to investigate closely linked symbiotic relationships between robots and natural plants and to explore the potentials of a plant-robot society able to produce architectural artifacts and living spaces. These robot-plant bio-hybrids create synergies that allow...

Mixing systems for wet and dry plumes and cleaning equipment for the heat exchangers of the dry section. Two indispensible components of an effective and safe hybrid cooling tower

International Nuclear Information System (INIS)

Alt, W.

1990-01-01

At first glance, the hybrid cooling tower seems to be an ingenious combination of the well known components of an evaporative cooling tower and a dry cooling tower. The calculation of the air mass flows for both the wet and dry sections required to achieve an invisible plume does not represent an unsolvable problem to the engineer experienced in thermodynamics. The same also applies to the dimensioning of the heat exchangers and cooling fills. The hybrid cooling tower requires a well designed mixing system in order to ideally mix, the dry plume into the wet plume. If the cooling tower proves its efficiency during commissioning it is important that the ratio of the performance of the wet section to that of the dry section be maintained also in the long term. The performance of the fill in a wet cooling tower is consistently stable. Dirt deposits can form very quickly on the inner and outer surfaces of the heat exchangers of the dry section. In this case the thermal resistance increases rapidly. The respective performance of the wet and dry sections is then no longer balanced and the invisibility of the plume is no longer assured. This can be avoided by providing appropriate cleaning equipment

Conventional, hybrid, plug-in hybrid or electric vehicles? State-based comparative carbon and energy footprint analysis in the United States

International Nuclear Information System (INIS)

Onat, Nuri Cihat; Kucukvar, Murat; Tatari, Omer

2015-01-01

Highlights: • Driving patterns and electricity generation mix influence vehicle preferences. • EVs are found to be least carbon-intensive vehicle option in 24 states. • HEVs are found to be the most energy-efficient option in 45 states. • EVs across the board are unfavorable in the marginal electricity mix scenario. • Use of renewable energy to power EVs/PHEVs is crucial. - Abstract: Electric vehicles (EVs), plug-in hybrid electric vehicles (PHEVs), and hybrid electric vehicles (HEVs) are often considered as better options in terms of greenhouse gas emissions and energy consumption compared to internal combustion vehicles. However, making any decision among these vehicle options is not a straightforward process due to temporal and spatial variations, such as the sources of the electricity used and regional driving patterns. In this study, we compared these vehicle options across 50 states, taking into account state-specific average and marginal electricity generation mixes, regional driving patterns, and vehicle and battery manufacturing impacts. Furthermore, a policy scenario proposing the widespread use of solar energy to charge EVs and PHEVs is evaluated. Based on the average electricity generation mix scenario, EVs are found to be least carbon-intensive vehicle option in 24 states, while HEVs are found to be the most energy-efficient option in 45 states. In the marginal electricity mix scenario, widespread adoption of EVs is found to be an unwise strategy given the existing and near-future marginal electricity generation mix. On the other hand, EVs can be superior to other alternatives in terms of energy-consumption, if the required energy to generate 1 kW h of electricity is below 1.25 kW h

Novel Hybrid Scheduling Technique for Sensor Nodes with Mixed Criticality Tasks

Directory of Open Access Journals (Sweden)

Mihai-Victor Micea

2017-06-01

Full Text Available Sensor networks become increasingly a key technology for complex control applications. Their potential use in safety- and time-critical domains has raised the need for task scheduling mechanisms specially adapted to sensor node specific requirements, often materialized in predictable jitter-less execution of tasks characterized by different criticality levels. This paper offers an efficient scheduling solution, named Hybrid Hard Real-Time Scheduling (H2RTS, which combines a static, clock driven method with a dynamic, event driven scheduling technique, in order to provide high execution predictability, while keeping a high node Central Processing Unit (CPU utilization factor. From the detailed, integrated schedulability analysis of the H2RTS, a set of sufficiency tests are introduced and demonstrated based on the processor demand and linear upper bound metrics. The performance and correct behavior of the proposed hybrid scheduling technique have been extensively evaluated and validated both on a simulator and on a sensor mote equipped with ARM7 microcontroller.

Novel Hybrid Scheduling Technique for Sensor Nodes with Mixed Criticality Tasks.

Science.gov (United States)

Micea, Mihai-Victor; Stangaciu, Cristina-Sorina; Stangaciu, Valentin; Curiac, Daniel-Ioan

2017-06-26

Sensor networks become increasingly a key technology for complex control applications. Their potential use in safety- and time-critical domains has raised the need for task scheduling mechanisms specially adapted to sensor node specific requirements, often materialized in predictable jitter-less execution of tasks characterized by different criticality levels. This paper offers an efficient scheduling solution, named Hybrid Hard Real-Time Scheduling (H²RTS), which combines a static, clock driven method with a dynamic, event driven scheduling technique, in order to provide high execution predictability, while keeping a high node Central Processing Unit (CPU) utilization factor. From the detailed, integrated schedulability analysis of the H²RTS, a set of sufficiency tests are introduced and demonstrated based on the processor demand and linear upper bound metrics. The performance and correct behavior of the proposed hybrid scheduling technique have been extensively evaluated and validated both on a simulator and on a sensor mote equipped with ARM7 microcontroller.

Positioning and tail rotor of a small horizontal axis wind turbine of due to the influence of drag coefficient and lift affecting vane cola

International Nuclear Information System (INIS)

Farinnas Wong, E. Y.; Jauregui Rigo, S.; Betancourt Mena, J.

2009-01-01

In the present investigation was carried out an assessment on the state of technology on guidance systems and tail protection when used in small horizontal axis wind turbines, work was improved methodological approach for the development of guidance systems queue by time of these machines, to incorporate the use of coefficients of lift and drag behavior varies according to the aspect ratio, using the principles of continuum mechanics and CFD methods. Two versions are analyzed , original and updated, the wind turbine CEET-01, on which the author would have been granted a Certificate of Patent of Invention and one of Industrial Model, the updated version was derived from the procedure proposed by the author, this presents a holder for the longest vane and a larger area in the vane. In addition to analyzing the amount and cost of power generated and the capacity factor at three locations in the province of Villa Clara it was concluded that the updated variant of the turbine CEET-01 is superior to the original

Design and aerodynamic performance evaluation of a high-work mixed flow turbine stage

Science.gov (United States)

Neri, Remo N.; Elliott, Thomas J.; Marsh, David N.; Civinskas, Kestutis C.

1994-01-01

As axial and radial turbine designs have been pushed to their aerothermodynamic and mechanical limits, the mixed-flow turbine (MFT) concept has been projected to offer performance and durability improvements, especially when ceramic materials are considered. The objective of this NASA/U.S. Army sponsored mixed-flow turbine (AMFT) program was to determine the level of performance attainable with MFT technology within the mechanical constraints of 1997 projected ceramic material properties. The MFT geometry is similar to a radial turbine, exhibiting a large radius change from inlet to exit, but differing in that the inlet flowpath is not purely radial, nor axial, but mixed; it is the inlet geometry that gives rise to the name 'mixed-flow'. The 'mixed' orientation of the turbine inlet offers several advantages over radial designs by allowing a nonzero inlet blade angle yet maintaining radial-element blades. The oblique inlet not only improves the particle-impact survivability of the design, but improves the aerodynamic performance by reducing the incidence at the blade inlet. The difficulty, however, of using mixed-flow geometry lies in the scarcity of detailed data and documented design experience. This paper reports the design of a MFT stage designed with the intent to maximize aerodynamic performance by optimizing design parameters such as stage reaction, rotor incidence, flowpath shape, blade shape, vane geometry, and airfoil counts using 2-D, 3-D inviscid, and 3-D viscous computational fluid dynamics code. The aerodynamic optimization was accomplished while maintaining mechanical integrity with respect to vibration and stress levels in the rotor. A full-scale cold-flow rig test was performed with metallic hardware fabricated to the specifications of the hot ceramic geometry to evaluate the stage performance.

An interactive physics-based unmanned ground vehicle simulator leveraging open source gaming technology: progress in the development and application of the virtual autonomous navigation environment (VANE) desktop

Science.gov (United States)

Rohde, Mitchell M.; Crawford, Justin; Toschlog, Matthew; Iagnemma, Karl D.; Kewlani, Guarav; Cummins, Christopher L.; Jones, Randolph A.; Horner, David A.

2009-05-01

It is widely recognized that simulation is pivotal to vehicle development, whether manned or unmanned. There are few dedicated choices, however, for those wishing to perform realistic, end-to-end simulations of unmanned ground vehicles (UGVs). The Virtual Autonomous Navigation Environment (VANE), under development by US Army Engineer Research and Development Center (ERDC), provides such capabilities but utilizes a High Performance Computing (HPC) Computational Testbed (CTB) and is not intended for on-line, real-time performance. A product of the VANE HPC research is a real-time desktop simulation application under development by the authors that provides a portal into the HPC environment as well as interaction with wider-scope semi-automated force simulations (e.g. OneSAF). This VANE desktop application, dubbed the Autonomous Navigation Virtual Environment Laboratory (ANVEL), enables analysis and testing of autonomous vehicle dynamics and terrain/obstacle interaction in real-time with the capability to interact within the HPC constructive geo-environmental CTB for high fidelity sensor evaluations. ANVEL leverages rigorous physics-based vehicle and vehicle-terrain interaction models in conjunction with high-quality, multimedia visualization techniques to form an intuitive, accurate engineering tool. The system provides an adaptable and customizable simulation platform that allows developers a controlled, repeatable testbed for advanced simulations. ANVEL leverages several key technologies not common to traditional engineering simulators, including techniques from the commercial video-game industry. These enable ANVEL to run on inexpensive commercial, off-the-shelf (COTS) hardware. In this paper, the authors describe key aspects of ANVEL and its development, as well as several initial applications of the system.

Wind-tunnel calibration of a combined pitot-static tube and vane-type flow-angularity indicator at Mach numbers of 1.61 and 2.01

Science.gov (United States)

Sinclair, Archibald R; Mace, William D

1956-01-01

A limited calibration of a combined pitot-static tube and vane-type flow-angularity indicator has been made in the Langley 4- by 4-foot supersonic pressure tunnel at Mach numbers of 1.61 and 2.01. The results indicated that the angle-of-yaw indications were affected by unsymmetric shock effects at low angles of attack.

Studi Eksperimen Aliran Melalui Square Duct dan Square Elbow 90º dengan Double Guide Vane pada Variasi Sudut Bukaan Damper

Directory of Open Access Journals (Sweden)

Andrew Jaya Nazar

2017-01-01

Full Text Available Instalasi saluran udara tidak hanya berupa pipa lurus, tetapi juga terdapat fitting/aksesoris perpipaan misalnya elbow 90o dan damper. Aksesoris perpipaan ini berfungsi agar saluran udara dapat terpasang sesuai dengan kebutuhan. Namun, penggunaan aksesoris perpipaan ini menyebabkan bertambahnya pressure drop akibat adanya friction loss dan separation loss. Pemasangan guide vane pada elbow 90o diharapkan dapat mengurangi pressure drop karena dapat mengurangi terjadinya secondary flow, namun hal ini dapat menambah kerugian akibat gaya gesek. Saat ini penghematan energi menjadi sorotan terutama dalam dunia industri. Penurunan pressure drop pada belokan perpipaan sangat diharapkan, agar dapat menghemat energi lebih. Untuk itu perlu dilakukan usaha agar dapat menurunkan pressure drop yang terjadi. Penelitian ini dilakukan secara eksperimen dengan benda uji saluran udara yang terdiri dari: upstream duct (straight duct, square elbow 90o dengan r/Dh=1,5 dan dilengkapi double guide vane, damper, downstream duct (straight duct, dan induced fan. Pengukuran parameter yang dibutuhkan dilakukan dengan menggunakan: pitot tube, inclined manometer, pressure tranducer. Dari eksperimen ini diperoleh bahwa profil kecepatan pada masing-masing variasi sudut bukaan damper sudah mendekati keadaan recovery aliran pada akhir section baik dari bidang vertikal maupun horizontal. Pressure drop yang terjadi semakin naik seiring dengan bertambahnya nilai bilangan Reynolds dan sudut bukaan damper. Nilai konstanta damper semakin naik dari bukaan sudut 0o hingga 30o.

Numerical Study of the Effects of Thermal Barrier Coating and Turbulence Intensity on Cooling Performances of a Nozzle Guide Vane

Directory of Open Access Journals (Sweden)

Prasert Prapamonthon

2017-03-01

Full Text Available This work presents a numerical investigation of the combined effects of thermal barrier coating (TBC with mainstream turbulence intensity (Tu on a modified vane of the real film-cooled nozzle guide vane (NGV reported by Timko (NASA CR-168289. Using a 3D conjugate heat transfer (CHT analysis, the NGVs with and without TBC are simulated at three Tus (Tu = 3.3%, 10% and 20%. The overall cooling effectiveness, TBC effectiveness and heat transfer coefficient are analyzed and discussed. The results indicate the following three interesting phenomena: (1 TBC on the pressure side (PS is more effective than that on the suction side (SS due to a fewer number of film holes on the SS; (2 for all three Tus, the variation trends of the overall cooling effectiveness are similar, and TBC plays the positive and negative roles in heat flux at the same time, and significantly increases the overall cooling effectiveness in regions cooled ineffectively by cooling air; (3 when Tu increases, the TBC effect is more significant, for example, at the highest Tu (Tu = 20% the overall cooling effectiveness can increase as much as 24% in the film cooling ineffective regions, but near the trailing edge (TE and the exits and downstream of film holes on the SS, this phenomenon is slight.

Nanogel-quantum dot hybrid nanoparticles for live cell imaging

International Nuclear Information System (INIS)

Hasegawa, Urara; Nomura, Shin-ichiro M.; Kaul, Sunil C.; Hirano, Takashi; Akiyoshi, Kazunari

2005-01-01

We report here a novel carrier of quantum dots (QDs) for intracellular labeling. Monodisperse hybrid nanoparticles (38 nm in diameter) of QDs were prepared by simple mixing with nanogels of cholesterol-bearing pullulan (CHP) modified with amino groups (CHPNH 2 ). The CHPNH 2 -QD nanoparticles were effectively internalized into the various human cells examined. The efficiency of cellular uptake was much higher than that of a conventional carrier, cationic liposome. These hybrid nanoparticles could be a promising fluorescent probe for bioimaging

Hybrid Bridge Structures Made of Frp Composite and Concrete

Science.gov (United States)

Rajchel, Mateusz; Siwowski, Tomasz

2017-09-01

Despite many advantages over the conventional construction materials, the contemporary development of FRP composites in bridge engineering is limited due to high initial cost, low stiffness (in case of glass fibers) and sudden composite failure mode. In order to reduce the given limitations, mixed (hybrid) solutions connecting the FRP composites and conventional construction materials, including concrete, have been tested in many countries for 20 years. Shaping the hybrid structures based on the attributes of particular materials, aims to increase stiffness and reduce cost without losing the carrying capacity, lightness and easiness of bridges that includes such hybrid girders, and to avoid the sudden dangerous failure mode. In the following article, the authors described examples of hybrid road bridges made of FRP composite and concrete within the time of 20 years and presented the first Polish hybrid FRP-concrete road bridge. Also, the directions of further research, necessary to spread these innovative, advanced and sustainable bridge structures were indicated.

Investigating temporal patterns of a native bee community in a remnant North American bunchgrass prairie using blue vane traps.

Science.gov (United States)

Kimoto, Chiho; Debano, Sandra J; Thorp, Robbin W; Rao, Sujaya; Stephen, William P

2012-01-01

Native bees are important ecologically and economically because their role as pollinators fulfills a vital ecosystem service. Pollinators are declining due to various factors, including habitat degradation and destruction. Grasslands, an important habitat for native bees, are particularly vulnerable. One highly imperiled and understudied grassland type in the United States is the Pacific Northwest Bunchgrass Prairie. No studies have examined native bee communities in this prairie type. To fill this gap, the bee fauna of the Zumwalt Prairie, a large, relatively intact remnant of the Pacific Northwest Bunchgrass Prairie, was examined. Native bees were sampled during the summers of 2007 and 2008 in sixteen 40-ha study pastures on a plateau in northeastern Oregon, using a sampling method not previously used in grassland studies-blue vane traps. This grassland habitat contained an abundant and diverse community of native bees that experienced marked seasonal and inter-annual variation, which appears to be related to weather and plant phenology. Temporal variability evident over the entire study area was also reflected at the individual trap level, indicating a consistent response across the spatial scale of the study. These results demonstrate that temporal variability in bee communities can have important implications for long-term monitoring protocols. In addition, the blue vane trap method appears to be well-suited for studies of native bees in large expanses of grasslands or other open habitats, and may be a useful tool for monitoring native bee communities in these systems.

Forecasting carbon dioxide emissions based on a hybrid of mixed data sampling regression model and back propagation neural network in the USA.

Science.gov (United States)

Zhao, Xin; Han, Meng; Ding, Lili; Calin, Adrian Cantemir

2018-01-01

The accurate forecast of carbon dioxide emissions is critical for policy makers to take proper measures to establish a low carbon society. This paper discusses a hybrid of the mixed data sampling (MIDAS) regression model and BP (back propagation) neural network (MIDAS-BP model) to forecast carbon dioxide emissions. Such analysis uses mixed frequency data to study the effects of quarterly economic growth on annual carbon dioxide emissions. The forecasting ability of MIDAS-BP is remarkably better than MIDAS, ordinary least square (OLS), polynomial distributed lags (PDL), autoregressive distributed lags (ADL), and auto-regressive moving average (ARMA) models. The MIDAS-BP model is suitable for forecasting carbon dioxide emissions for both the short and longer term. This research is expected to influence the methodology for forecasting carbon dioxide emissions by improving the forecast accuracy. Empirical results show that economic growth has both negative and positive effects on carbon dioxide emissions that last 15 quarters. Carbon dioxide emissions are also affected by their own change within 3 years. Therefore, there is a need for policy makers to explore an alternative way to develop the economy, especially applying new energy policies to establish a low carbon society.

Local hybrid functionals: An assessment for thermochemical kinetics

International Nuclear Information System (INIS)

Kaupp, Martin; Bahmann, Hilke; Arbuznikov, Alexei V.

2007-01-01

Local hybrid functionals with position-dependent exact-exchange admixture are a new class of exchange-correlation functionals in density functional theory that promise to advance the available accuracy in many areas of application. Local hybrids with different local mixing functions (LMFs) governing the position dependence are validated for the heats of formation of the extended G3/99 set, and for two sets of barriers of hydrogen-transfer and heavy-atom transfer reactions (HTBH38 and NHTBH38 databases). A simple local hybrid Lh-SVWN with only Slater and exact exchange plus local correlation and a one-parameter LMF, g(r)=b(τ W (r)/τ(r)), performs best and provides overall mean absolute errors for thermochemistry and kinetics that are a significant improvement over standard state-of-the-art global hybrid functionals. In particular, this local hybrid functional does not suffer from the systematic deterioration that standard functionals exhibit for larger molecules. In contrast, local hybrids based on generalized gradient approximation exchange tend to give rise to nonintuitive LMFs, and no improved functionals have been obtained along this route. The LMF is a real-space function and thus can be analyzed in detail. We use, in particular, graphical analyses to rationalize the performance of different local hybrids for thermochemistry and reaction barriers

Stillwater Hybrid Geo-Solar Power Plant Optimization Analyses

Energy Technology Data Exchange (ETDEWEB)

Wendt, Daniel S.; Mines, Gregory L.; Turchi, Craig S.; Zhu, Guangdong; Cohan, Sander; Angelini, Lorenzo; Bizzarri, Fabrizio; Consoli, Daniele; De Marzo, Alessio

2015-09-02

The Stillwater Power Plant is the first hybrid plant in the world able to bring together a medium-enthalpy geothermal unit with solar thermal and solar photovoltaic systems. Solar field and power plant models have been developed to predict the performance of the Stillwater geothermal / solar-thermal hybrid power plant. The models have been validated using operational data from the Stillwater plant. A preliminary effort to optimize performance of the Stillwater hybrid plant using optical characterization of the solar field has been completed. The Stillwater solar field optical characterization involved measurement of mirror reflectance, mirror slope error, and receiver position error. The measurements indicate that the solar field may generate 9% less energy than the design value if an appropriate tracking offset is not employed. A perfect tracking offset algorithm may be able to boost the solar field performance by about 15%. The validated Stillwater hybrid plant models were used to evaluate hybrid plant operating strategies including turbine IGV position optimization, ACC fan speed and turbine IGV position optimization, turbine inlet entropy control using optimization of multiple process variables, and mixed working fluid substitution. The hybrid plant models predict that each of these operating strategies could increase net power generation relative to the baseline Stillwater hybrid plant operations.

Formulation and Validation of an Efficient Computational Model for a Dilute, Settling Suspension Undergoing Rotational Mixing

Energy Technology Data Exchange (ETDEWEB)

Sprague, Michael A.; Stickel, Jonathan J.; Sitaraman, Hariswaran; Crawford, Nathan C.; Fischer, Paul F.

2017-04-11

Designing processing equipment for the mixing of settling suspensions is a challenging problem. Achieving low-cost mixing is especially difficult for the application of slowly reacting suspended solids because the cost of impeller power consumption becomes quite high due to the long reaction times (batch mode) or due to large-volume reactors (continuous mode). Further, the usual scale-up metrics for mixing, e.g., constant tip speed and constant power per volume, do not apply well for mixing of suspensions. As an alternative, computational fluid dynamics (CFD) can be useful for analyzing mixing at multiple scales and determining appropriate mixer designs and operating parameters. We developed a mixture model to describe the hydrodynamics of a settling cellulose suspension. The suspension motion is represented as a single velocity field in a computationally efficient Eulerian framework. The solids are represented by a scalar volume-fraction field that undergoes transport due to particle diffusion, settling, fluid advection, and shear stress. A settling model and a viscosity model, both functions of volume fraction, were selected to fit experimental settling and viscosity data, respectively. Simulations were performed with the open-source Nek5000 CFD program, which is based on the high-order spectral-finite-element method. Simulations were performed for the cellulose suspension undergoing mixing in a laboratory-scale vane mixer. The settled-bed heights predicted by the simulations were in semi-quantitative agreement with experimental observations. Further, the simulation results were in quantitative agreement with experimentally obtained torque and mixing-rate data, including a characteristic torque bifurcation. In future work, we plan to couple this CFD model with a reaction-kinetics model for the enzymatic digestion of cellulose, allowing us to predict enzymatic digestion performance for various mixing intensities and novel reactor designs.

Experimental study into a hybrid PCCI/CI concept for next-generation heavy-duty diesel engines

NARCIS (Netherlands)

Doosje, E.; Willems, F.P.T.; Baert, R.S.G.; Dijk, M.D. van

2012-01-01

This paper presents the first results of an experimental study into a hybrid combustion concept for next-generation heavy-duty diesel engines. In this hybrid concept, at low load operating conditions, the engine is run in Pre-mixed Charge Compression Ignition (PCCI) mode, whereas at high load

Expanded Mixed Multiscale Finite Element Methods and Their Applications for Flows in Porous Media

KAUST Repository

Jiang, L.

2012-01-01

We develop a family of expanded mixed multiscale finite element methods (MsFEMs) and their hybridizations for second-order elliptic equations. This formulation expands the standard mixed multiscale finite element formulation in the sense that four unknowns (hybrid formulation) are solved simultaneously: pressure, gradient of pressure, velocity, and Lagrange multipliers. We use multiscale basis functions for both the velocity and the gradient of pressure. In the expanded mixed MsFEM framework, we consider both separable and nonseparable spatial scales. Specifically, we analyze the methods in three categories: periodic separable scales, G-convergent separable scales, and a continuum of scales. When there is no scale separation, using some global information can significantly improve the accuracy of the expanded mixed MsFEMs. We present a rigorous convergence analysis of these methods that includes both conforming and nonconforming formulations. Numerical results are presented for various multiscale models of flow in porous media with shale barriers that illustrate the efficacy of the proposed family of expanded mixed MsFEMs. © 2012 Society for Industrial and Applied Mathematics.

The Hybrid II assay: a sensitive and specific real-time hybridization assay for the diagnosis of Theileria parva infection in Cape buffalo (Syncerus caffer) and cattle.

Science.gov (United States)

Pienaar, Ronel; Potgieter, Fred T; Latif, Abdalla A; Thekisoe, Oriel M M; Mans, Ben J

2011-12-01

Corridor disease is an acute, fatal disease of cattle caused by buffalo-adapted Theileria parva. This is a nationally controlled disease in South Africa and strict control measures apply for the movement of buffalo, which includes mandatory testing for the presence of T. parva and other controlled diseases. Accurate diagnosis of the T. parva carrier state in buffalo using the official real-time hybridization PCR assay (Sibeko et al. 2008), has been shown to be affected by concurrent infection with T. sp. (buffalo)-like parasites. We describe the Hybrid II assay, a real-time hybridization PCR method, which compares well with the official hybridization assay in terms of specificity and sensitivity. It is, however, not influenced by mixed infections of T. sp. (buffalo)-like parasites and is as such a significant improvement on the current hybridization assay.

Modelling of hybrid energy system - Part I: Problem formulation and model development

Energy Technology Data Exchange (ETDEWEB)

Gupta, Ajai; Saini, R.P.; Sharma, M.P. [Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India)

2011-02-15

A well designed hybrid energy system can be cost effective, has a high reliability and can improve the quality of life in remote rural areas. The economic constraints can be met, if these systems are fundamentally well designed, use appropriate technology and make use effective dispatch control techniques. The first paper of this tri-series paper, presents the analysis and design of a mixed integer linear mathematical programming model (time series) to determine the optimal operation and cost optimization for a hybrid energy generation system consisting of a photovoltaic array, biomass (fuelwood), biogas, small/micro-hydro, a battery bank and a fossil fuel generator. The optimization is aimed at minimizing the cost function based on demand and potential constraints. Further, mathematical models of all other components of hybrid energy system are also developed. This is the generation mix of the remote rural of India; it may be applied to other rural areas also. (author)

Experimental measurements and analytical analysis related to gas turbine heat transfer. Part 1: Time-averaged heat-flux and surface-pressure measurements on the vanes and blades of the SSME fuel-side turbine and comparison with prediction. Part 2: Phase-resolved surface-pressure and heat-flux measurements on the first blade of the SSME fuel-side turbine

Science.gov (United States)

1994-01-01

Time averaged Stanton number and surface-pressure distributions are reported for the first-stage vane row, the first stage blade row, and the second stage vane row of the Rocketdyne Space Shuttle Main Engine two-stage fuel-side turbine. Unsteady pressure envelope measurements for the first blade are also reported. These measurements were made at 10 percent, 50 percent, and 90 percent span on both the pressure and suction surfaces of the first stage components. Additional Stanton number measurements were made on the first stage blade platform blade tip, and shroud, and at 50 percent span on the second vane. A shock tube was used as a short duration source of heated and pressurized air to which the turbine was subjected. Platinum thin-film heat flux gages were used to obtain the heat flux measurements, while miniature silicon-diaphragm flush-mounted pressure transducers were used to obtain the pressure measurements. The first stage vane Stanton number distributions are compared with predictions obtained using a version of STAN5 and a quasi-3D Navier-Stokes solution. This same quasi-3D N-S code was also used to obtain predictions for the first blade and the second vane.

Experimental evaluation of different mixing promoter for nuclear fuel element by means of a new thermal tracing technique

International Nuclear Information System (INIS)

Silin, Nicolas; Juanico, Luis; Delmastro, Dario

2004-01-01

In this work a new experimental method is used to experimentally evaluate the performance of different appendages promoting the turbulent mixing between the coupled subchannels of nuclear fuel elements.The method used will be introduced in another presentation and consists in the generation and measurement of small thermal traces in the refrigerating water flow between the fuel rods.Because it is suitable for heterogeneous and compact subchannels (as Argentinean fuels) with high water flows in simple and affordable tests at atmospheric pressure, this new method is specially well suited for the design of fuel elements, while it offers advantages over other methods of mixing measurement.The experiments carried out on a small test section proved that the buttons brazed to the fuel rods (similar to the 'turbulence promoters' of the Canflex fuel) had an excellent thermohydraulic performance as compared to different mixing vane designs studied.The thermal traces method developed has shown its potential as a thermohydraulic design tool for the development of advanced nuclear fuels, that eventually incorporate mixing promoter elements. In the case of CARA, and as it includes spacer grids, it could be possible to use them to incorporate these elements without the need of brazing them to the rods (as is the case in Canflex), and therefore without penalizing its integrity [es

Hybrid, plug-in hybrid, or electric—What do car buyers want?

International Nuclear Information System (INIS)

Axsen, Jonn; Kurani, Kenneth S.

2013-01-01

We use a survey to compare consumers’ stated interest in conventional gasoline (CV), hybrid (HEV), plug-in hybrid (PHEV) and pure electric vehicles (EV) of varying designs and prices. Data are from 508 households representing new vehicle buyers in San Diego County, California in 2011. The mixed-mode survey collected information about access to residential recharge infrastructure, three days of driving patterns, and desired vehicle designs and motivations via design games. Across the higher and lower price scenarios, a majority of consumers designed and selected some form of PHEV for their next new vehicle, smaller numbers designed an HEV or a conventional vehicle, and only a few percent designed an EV. Of those who did not design an EV, the most frequent concerns with EVs were limited range, charger availability, and higher vehicle purchase prices. Positive interest in HEVs, PHEVs and EVs was associated with vehicle images of intelligence, responsibility, and support of the environment and nation (United States). The distribution of vehicle designs suggests that cheaper, smaller battery PHEVs may achieve more short-term market success than larger battery PHEVs or EV. New car buyers’ present interests align with less expensive first steps in a transition to electric-drive vehicles. - Highlights: • We assess consumer interest in various electric-drive vehicle designs. • Web-based design games completed by 508 households from San Diego, California. • Plug-in hybrids are most popular, followed by hybrids and conventional vehicles. • Only a few percent opted for a pure electric vehicle. • Electric-drive associated with intelligence, responsibility, and environment

Combustion-driven oscillation in a furnace with multispud-type gas burners. 4th Report. Effects of position of secondary air guide sleeve and openness of secondary air guide vane on combustion oscillation condition; Multispud gata gas turner ni okeru nensho shindo. 4. Nijigen kuki sleeve ichi oyobi nijigen kuki vane kaido no shindo reiki ni oyobosu eikyo

Energy Technology Data Exchange (ETDEWEB)

Akiyama, I.; Okiura, K.; Baba, A.; Orimoto, M. [Babcock-Hitachi K.K., Tokyo (Japan)

1994-07-25

Effects of the position of a secondary air guide sleeve and the openness of a secondary air guide vane on combustion oscillation conditions were studied experimentally for multispud-type gas burners. Pressure fluctuation in furnaces was analyzed with the previously reported resonance factor which was proposed as an index to represent the degree of combustion oscillation. As a result, the combustion oscillation region was largely affected by both position of a guide sleeve and openness of a guide vane. As the openness having large effect on the ratio of primary and secondary air/tertiary air and the position hardly having effect on the ratio were adjusted skillfully, the burner with no combustion oscillation region was achieved in its normal operation range. In addition, as the effect of preheating combustion air was arranged with a standard flow rate or mass flow flux of air, it was suggested the combustion oscillation region due to preheating can be described with the same manner as that due to no preheating. 5 refs., 8 figs.

Hybridization Associated with Cycles of Ecological Succession in a Passerine Bird.

Science.gov (United States)

Duckworth, Renée A; Semenov, Georgy A

2017-10-01

Identifying the diversity of contexts that can lead to hybridization is important for understanding its prevalence and dynamics in natural populations. Despite the potential of ecological succession to dramatically alter species co-occurrence and abundances, it is unknown whether it directly promotes hybridization and, if so, has long-lasting consequences. Here, we summarize 30 years of survey data across 10 populations to show that in western and mountain bluebirds, heterospecific pairing occurs during repeatable and transient colonization events at the early stages of species turnover. Despite mixed pairing occurring only during early succession, genetic data showed presence of hybrids at both early and late successional stages. Moreover, hybrids showed novel patterns of variation in morphology and behavior, emphasizing that even ephemeral contexts for hybridization can have important evolutionary consequences. Our results suggest that because ecological succession often brings together closely related competitors in disparate numbers but lasts for only a brief period of time, it may be a widespread but underappreciated context for hybridization.

Synergetic Hybrid Aerogels of Vanadia and Graphene as Electrode Materials of Supercapacitors

Directory of Open Access Journals (Sweden)

Xuewei Fu

2016-08-01

Full Text Available The performance of synergetic hybrid aerogel materials of vanadia and graphene as electrode materials in supercapacitors was evaluated. The hybrid materials were synthesized by two methods. In Method I, premade graphene oxide (GO hydrogel was first chemically reduced by L-ascorbic acid and then soaked in vanadium triisopropoxide solution to obtain V2O5 gel in the pores of the reduced graphene oxide (rGO hydrogel. The gel was supercritically dried to obtain the hybrid aerogel. In Method II, vanadium triisopropoxide was hydrolyzed from a solution in water with GO particles uniformly dispersed to obtain the hybrid gel. The hybrid aerogel was obtained by supercritical drying of the gel followed by thermal reduction of GO. The electrode materials were prepared by mixing 80 wt % hybrid aerogel with 10 wt % carbon black and 10 wt % polyvinylidene fluoride. The hybrid materials in Method II showed higher capacitance due to better interactions between vanadia and graphene oxide particles and more uniform vanadia particle distribution.

Hybrid Modeling and Optimization of Yogurt Starter Culture Continuous Fermentation

Directory of Open Access Journals (Sweden)

Silviya Popova

2009-10-01

Full Text Available The present paper presents a hybrid model of yogurt starter mixed culture fermentation. The main nonlinearities within a classical structure of continuous process model are replaced by neural networks. The new hybrid model accounts for the dependence of the two microorganisms' kinetics from the on-line measured characteristics of the culture medium - pH. Then the model was used further for calculation of the optimal time profile of pH. The obtained results are with agreement with the experimental once.

Characterizations of Polystyrene-Based Hybrid Particles Containing Hydrophobic Mg(OH2 Powder and Composites Fabricated by Employing Resultant Hybrid Particles

Directory of Open Access Journals (Sweden)

Shuichi Kimura

2007-01-01

unchanged, even when the ST-1 powder content increased from 10 to 50 phr. Furthermore, a composite fabricated by employing the hybrid particles achieved homogenous distribution of ST-1 powder and showed a higher oxygen index than that of a composite fabricated by directly mixing of PS pellets and ST-1 powder.

Numerical Analysis for IFM Grid Effect on 5x5 Rods Bundle

International Nuclear Information System (INIS)

Kim, Seong Jin; Cha, Jeong Hun; Seo, Kyong Won; Kim, Tae Woo; Kwon, Hyuk; Hwang, Dae Hyun

2011-01-01

Generally, the fuel assembly consists of fuel rods, bottom and top grids, spacer grids, mixing vane, etc. The mixing vane with spacer grid is used to increase the thermal mixing between subchannels and to increase CHF(Critical Heat Flux). IFM(Intermediate Flow Mixer) grids are used to induce lateral flow between adjacent channels and are well-known as improving CHF, also. A numerical analysis using CFD code(ANSYS CFX, version 12.1) and subchannel code(MATRA-S) was conducted to investigate the influence of IFM grid on the subchannel temperature in 5x5 rods bundle with and without the IFM grid, thermohydraulically. In this study, the quantitative improvement of the mixing effect of the IFM grid is presented from the results of CFX and MATRA-S code. Moreover, capacity of predicting subchannel temperature of MATRA-S code is compared with CFX result

Hybrid Predictive Control for Dynamic Transport Problems

CERN Document Server

Núñez, Alfredo A; Cortés, Cristián E

2013-01-01

Hybrid Predictive Control for Dynamic Transport Problems develops methods for the design of predictive control strategies for nonlinear-dynamic hybrid discrete-/continuous-variable systems. The methodology is designed for real-time applications, particularly the study of dynamic transport systems. Operational and service policies are considered, as well as cost reduction. The control structure is based on a sound definition of the key variables and their evolution. A flexible objective function able to capture the predictive behaviour of the system variables is described. Coupled with efficient algorithms, mainly drawn from the area of computational intelligence, this is shown to optimize performance indices for real-time applications. The framework of the proposed predictive control methodology is generic and, being able to solve nonlinear mixed-integer optimization problems dynamically, is readily extendable to other industrial processes. The main topics of this book are: ●hybrid predictive control (HPC) ...

Hybrid Reynolds-Averaged/Large-Eddy Simulations of a Coaxial Supersonic Free-Jet Experiment

Science.gov (United States)

Baurle, Robert A.; Edwards, Jack R.

2010-01-01

Reynolds-averaged and hybrid Reynolds-averaged/large-eddy simulations have been applied to a supersonic coaxial jet flow experiment. The experiment was designed to study compressible mixing flow phenomenon under conditions that are representative of those encountered in scramjet combustors. The experiment utilized either helium or argon as the inner jet nozzle fluid, and the outer jet nozzle fluid consisted of laboratory air. The inner and outer nozzles were designed and operated to produce nearly pressure-matched Mach 1.8 flow conditions at the jet exit. The purpose of the computational effort was to assess the state-of-the-art for each modeling approach, and to use the hybrid Reynolds-averaged/large-eddy simulations to gather insight into the deficiencies of the Reynolds-averaged closure models. The Reynolds-averaged simulations displayed a strong sensitivity to choice of turbulent Schmidt number. The initial value chosen for this parameter resulted in an over-prediction of the mixing layer spreading rate for the helium case, but the opposite trend was observed when argon was used as the injectant. A larger turbulent Schmidt number greatly improved the comparison of the results with measurements for the helium simulations, but variations in the Schmidt number did not improve the argon comparisons. The hybrid Reynolds-averaged/large-eddy simulations also over-predicted the mixing layer spreading rate for the helium case, while under-predicting the rate of mixing when argon was used as the injectant. The primary reason conjectured for the discrepancy between the hybrid simulation results and the measurements centered around issues related to the transition from a Reynolds-averaged state to one with resolved turbulent content. Improvements to the inflow conditions were suggested as a remedy to this dilemma. Second-order turbulence statistics were also compared to their modeled Reynolds-averaged counterparts to evaluate the effectiveness of common turbulence closure

Nonlinear spatial mode imaging of hybrid photonic crystal fibers

DEFF Research Database (Denmark)

Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Laurila, Marko

2013-01-01

Degenerate spontaneous four wave mixing is studied for the rst time in a large mode area hybrid photonic crystal ber, where light con nement is achieved by combined index- and bandgap guiding. Four wave mixing products are generated on the edges of the bandgaps, which is veri ed by numerical and ...... and experimental results. Since the core mode is in resonance with cladding modes near the bandedges an unconventional measurement technique is used, in this work named nonlinear spatial mode imaging....

Preparation and Characterization of Organic-Inorganic Hybrid Hydrogel Electrolyte Using Alkaline Solution

OpenAIRE

Chiku, Masanobu; Tomita, Shoji; Higuchi, Eiji; Inoue, Hiroshi

2011-01-01

Organic-inorganic hybrid hydrogel electrolytes were prepared by mixing hydrotalcite, cross-linked potassium poly(acrylate) and 6 M KOH solution. The organic-inorganic hybrid hydrogel electrolytes had high ionic conductivity (0.456–0.540 S cm−1) at 30 °C. Moreover, the mechanical strength of the hydrogel electrolytes was high enough to form a 2–3 mm thick freestanding membrane because of the reinforcement with hydrotalcite.

Towards improved local hybrid functionals by calibration of exchange-energy densities

International Nuclear Information System (INIS)

Arbuznikov, Alexei V.; Kaupp, Martin

2014-01-01

A new approach for the calibration of (semi-)local and exact exchange-energy densities in the context of local hybrid functionals is reported. The calibration functions are derived from only the electron density and its spatial derivatives, avoiding spatial derivatives of the exact-exchange energy density or other computationally unfavorable contributions. The calibration functions fulfill the seven more important out of nine known exact constraints. It is shown that calibration improves substantially the definition of a non-dynamical correlation energy term for generalized gradient approximation (GGA)-based local hybrids. Moreover, gauge artifacts in the potential-energy curves of noble-gas dimers may be corrected by calibration. The developed calibration functions are then evaluated for a large range of energy-related properties (atomization energies, reaction barriers, ionization potentials, electron affinities, and total atomic energies) of three sets of local hybrids, using a simple one-parameter local-mixing. The functionals are based on (a) local spin-density approximation (LSDA) or (b) Perdew-Burke-Ernzerhof (PBE) exchange and correlation, and on (c) Becke-88 (B88) exchange and Lee-Yang-Parr (LYP) correlation. While the uncalibrated GGA-based functionals usually provide very poor thermochemical data, calibration allows a dramatic improvement, accompanied by only a small deterioration of reaction barriers. In particular, an optimized BLYP-based local-hybrid functional has been found that is a substantial improvement over the underlying global hybrids, as well as over previously reported LSDA-based local hybrids. It is expected that the present calibration approach will pave the way towards new generations of more accurate hyper-GGA functionals based on a local mixing of exchange-energy densities

Surface-enhanced Raman effect in hybrid metal–semiconductor nanoparticle assemblies

International Nuclear Information System (INIS)

Lughi, Vanni; Bonifacio, Alois; Barbone, Matteo; Marsich, Lucia; Sergo, Valter

2013-01-01

Hybrid metal–semiconductor nanoparticles consisting of silver nanoparticle cores (AgNPs) coated with a layer of CdSe quantum dots (QDs) have been studied by Raman spectroscopy. The hybrid nanoparticles were prepared via electrostatic interaction by mixing aqueous suspensions of QDs and AgNPs, where opposite charges on the AgNPs and QDs surfaces were induced by opportunely selected capping agents. Assemblies of such hybrid nanoparticles show an increased intensity of the Raman spectrum of up to 500 times, when compared to that of the sole QDs. This enhancement is attributed to the SERS effect (Surface-enhanced Raman scattering). Such enhancement of the Raman modes suggests several opportunities for further research, both in imaging and sensing applications.

Preparation of mixed molecularly imprinted polymer magnetic nanoparticles and its application in separation of Chinese traditional medicine

Science.gov (United States)

Xie, Yihui; Ma, Yajuan; Bai, Wenting; Zhu, Xiaofang; Liu, Min; Huang, Liping

2017-08-01

A mixed imprinted polymer which can rapidly adsorb all flavonoids from raspberry extract was prepared and recycled. The hybrid molecular surface imprinted polymers were prepared by using quercetin as the template molecule and Fe3O4 magnetic nanospheres as the carrier. The molecular imprinting polymer was prepared by using the "initial template molecule, molecularly imprinted polymer, mixed template molecule, molecularly imprint ted polymers (MIPS)". The adsorption performance and durability of the hybrid molecularly imprinted polymers were investigated by using the fingerprints of the ethyl acetate fraction of raspberry as an index. The adsorption of flavonoids from raspberry extract, lindenoside, cis-lindenin, quercetin, kaempferol and other flavonoids was completely adsorbed by mixed molecular-imprinted polymer, and the other components were basically adsorbed. When Mix-IMPs were repeatedly used 10 times, the fingerprints showed that the content and content of flavonoids were basically the same. The experimental results show that Mix-IMPs has good adsorption performance, can be recycled and used for rapid enrichment of flavonoids in raspberry.

Manitoba plug-in hybrid electric vehicle (PHEV) demonstration

Energy Technology Data Exchange (ETDEWEB)

Hoemsen, R. [Red River College, Winnipeg, MB (Canada); Parsons, R. [Government of Manitoba, Winnipeg, MB (Canada). Centre for Emerging Renewable Energy

2010-07-01

Manitoba has low electricity rates, the highest proportion of renewables, and a legislated commitment to reduce greenhouse gases. However, the province still relies heavily on oil as everyone else. The mix of energy opportunities in Manitoba were highlighted in this presentation, with particular reference to the commercialization of electric vehicles. Several photographs were presented of the Toyota plug-in hybrid vehicle and a plug-in hybrid electric demonstration vehicle. A demonstration project overview was offered that used technology from A123 Systems Inc. The conversion module and vehicle users were profiled. Topics that were presented related to the demonstration project included monitoring; gasoline fuel economy results; fuel economy variability; cold weather operation; cold weather issues; battery upgrade solutions; and highly qualified personnel. It was concluded that in terms of follow-up, there is a need to combine findings of current plug-in hybrid electric vehicle demonstration with those for the new Toyota production plug-in hybrid vehicles. Key next steps for the demonstration are to address cabin heating requirements; better characterizing winter performance; and implementation of IPLC units on all plug-in hybrid electric vehicles for electricity consumption. figs.

Single axis controlled hybrid magnetic bearing for left ventricular assist device: hybrid core and closed magnetic circuit.

Science.gov (United States)

da Silva, Isaias; Horikawa, Oswaldo; Cardoso, Jose R; Camargo, Fernando A; Andrade, Aron J P; Bock, Eduardo G P

2011-05-01

In previous studies, we presented main strategies for suspending the rotor of a mixed-flow type (centrifugal and axial) ventricular assist device (VAD), originally presented by the Institute Dante Pazzanese of Cardiology (IDPC), Brazil. Magnetic suspension is achieved by the use of a magnetic bearing architecture in which the active control is executed in only one degree of freedom, in the axial direction of the rotor. Remaining degrees of freedom, excepting the rotation, are restricted only by the attraction force between pairs of permanent magnets. This study is part of a joint project in development by IDPC and Escola Politecnica of São Paulo University, Brazil. This article shows advances in that project, presenting two promising solutions for magnetic bearings. One solution uses hybrid cores as electromagnetic actuators, that is, cores that combine iron and permanent magnets. The other solution uses actuators, also of hybrid type, but with the magnetic circuit closed by an iron core. After preliminary analysis, a pump prototype has been developed for each solution and has been tested. For each prototype, a brushless DC motor has been developed as the rotor driver. Each solution was evaluated by in vitro experiments and guidelines are extracted for future improvements. Tests have shown good results and demonstrated that one solution is not isolated from the other. One complements the other for the development of a single-axis-controlled, hybrid-type magnetic bearing for a mixed-flow type VAD. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Energy Performance and Radial Force of a Mixed-Flow Pump with Symmetrical and Unsymmetrical Tip Clearances

Directory of Open Access Journals (Sweden)

Yue Hao

2017-01-01

Full Text Available The energy performance and radial force of a mixed flow pump with symmetrical and unsymmetrical tip clearance are investigated in this paper. As the tip clearance increases, the pump head and efficiency both decrease. The center of the radial force on the principal axis is located at the coordinate origin when the tip clearance is symmetrical, and moves to the third quadrant when the tip clearance is unsymmetrical. Analysis results show that the total radial force on the principal axis is closely related to the fluctuation of mass flow rate in each single flow channel. Unsteady simulations show that the dominant frequencies of radial force on the hub and blade correspond to the blade number, vane number, or double blade number because of the rotor stator interaction. The radial force on the blade pressure side decreases with the tip clearance increase because of leakage flow. The unsymmetrical tip clearances in an impeller induce uneven leakage flow rate and then result in unsymmetrical work ability of each blade and flow pattern in each channel. Thus, the energy performance decreases and the total radial force increases for a mixed flow pump with unsymmetrical tip clearance.

Impact on DNB predictions of mixing models implemented into the three-dimensional thermal-hydraulic code Thyc

International Nuclear Information System (INIS)

Banner, D.

1993-10-01

The objective of this paper is to point out how departure from nucleate boiling (DNB) predictions can be improved by the THYC software. The EPRI/Columbia University E161 data base has been used for this study. In a first step, three thermal-hydraulic mixing models have been implemented into the code in order to obtain more accurate calculations of local void fractions at the DNB location. The three investigated models (A, B and C) are presented by growing complexity. Model A assumes a constant turbulent viscosity throughout the flow. In model B, a k-L turbulence transport equation has been implemented to model generation and decay of turbulence in the DNB test section. Model C is obtained by representing oriented transverse flows due to mixing vanes in addition to the k-L equation. A parametric study carried out with the three mixing models exhibits the most significant parameters. The occurrence of departure from nucleate boiling is then predicted by using a DNB correlation. Similar results are obtained as long as the DNB correlation is kept unchanged. In a second step, an attempt to substitute correlations by another statistical approach (pseudo-cubic thin-plate type Spline method) has been done. It is then shown that standard deviations of P/M (predicted to measured) ratios can be greatly improved by advanced statistics. (author). 7 figs., 2 tabs., 9 refs

Groundscrapers : Vitalizing the Tradition of the Urban Low Rise, Mixed Hybrid Building

NARCIS (Netherlands)

Komossa, S.; Marzot, N.; Cavallo, R.

2014-01-01

The fact that hybrid buildings can be interpreted as extremely condensed urban blocks, increasing the city’s density and contributing to its public realm, forms one of the key interests of this research. According to its European interpretation, the “ground scraper” is not only public because of the

Vortex Generators in a Streamline-Traced, External-Compression Supersonic Inlet

Science.gov (United States)

Baydar, Ezgihan; Lu, Frank K.; Slater, John W.; Trefny, Charles J.

2017-01-01

Vortex generators within a streamline-traced, external-compression supersonic inlet for Mach 1.66 were investigated to determine their ability to increase total pressure recovery and reduce total pressure distortion. The vortex generators studied were rectangular vanes arranged in counter-rotating and co-rotating arrays. The vane geometric factors of interest included height, length, spacing, angle-of-incidence, and positions upstream and downstream of the inlet terminal shock. The flow through the inlet was simulated numerically through the solution of the steady-state, Reynolds-averaged Navier-Stokes equations on multi-block, structured grids using the Wind-US flow solver. The vanes were simulated using a vortex generator model. The inlet performance was characterized by the inlet total pressure recovery and the radial and circumferential total pressure distortion indices at the engine face. Design of experiments and statistical analysis methods were applied to quantify the effect of the geometric factors of the vanes and search for optimal vane arrays. Co-rotating vane arrays with negative angles-of-incidence positioned on the supersonic diffuser were effective in sweeping low-momentum flow from the top toward the sides of the subsonic diffuser. This distributed the low-momentum flow more evenly about the circumference of the subsonic diffuser and reduced distortion. Co-rotating vane arrays with negative angles-of-incidence or counter-rotating vane arrays positioned downstream of the terminal shock were effective in mixing higher-momentum flow with lower-momentum flow to increase recovery and decrease distortion. A strategy of combining a co-rotating vane array on the supersonic diffuser with a counter-rotating vane array on the subsonic diffuser was effective in increasing recovery and reducing distortion.

Importance of the correlation contribution for local hybrid functionals: range separation and self-interaction corrections.

Science.gov (United States)

Arbuznikov, Alexei V; Kaupp, Martin

2012-01-07

Local hybrid functionals with their position-dependent exact-exchange admixture are a conceptually simple and promising extension of the concept of a hybrid functional. Local hybrids based on a simple mixing of the local spin density approximation (LSDA) with exact exchange have been shown to be successful for thermochemistry, reaction barriers, and a range of other properties. So far, the combination of this generation of local hybrids with an LSDA correlation functional has been found to give the most favorable results for atomization energies, for a range of local mixing functions (LMFs) governing the exact-exchange admixture. Here, we show that the choice of correlation functional to be used with local hybrid exchange crucially influences the parameterization also of the exchange part as well as the overall performance. A novel ansatz for the correlation part of local hybrids is suggested based on (i) range-separation of LSDA correlation into short-range (SR) and long-range (LR) parts, and (ii) partial or full elimination of the one-electron self-correlation from the SR part. It is shown that such modified correlation functionals allow overall larger exact exchange admixture in thermochemically competitive local hybrids than before. This results in improvements for reaction barriers and for other properties crucially influenced by self-interaction errors, as demonstrated by a number of examples. Based on the range-separation approach, a fresh view on the breakdown of the correlation energy into dynamical and non-dynamical parts is suggested.

Preparation and Characterization of Organic-Inorganic Hybrid Hydrogel Electrolyte Using Alkaline Solution

Directory of Open Access Journals (Sweden)

Masanobu Chiku

2011-09-01

Full Text Available Organic-inorganic hybrid hydrogel electrolytes were prepared by mixing hydrotalcite, cross-linked potassium poly(acrylate and 6 M KOH solution. The organic-inorganic hybrid hydrogel electrolytes had high ionic conductivity (0.456–0.540 S cm−1 at 30 °C. Moreover, the mechanical strength of the hydrogel electrolytes was high enough to form a 2–3 mm thick freestanding membrane because of the reinforcement with hydrotalcite.

Comparative study of the contribution of various PWR spacer grid components to hydrodynamic and wall pressure characteristics

Energy Technology Data Exchange (ETDEWEB)

Bhattacharjee, Saptarshi, E-mail: saptarshi.bhattacharjee@outlook.com [Alternative Energies and Atomic Energy Commission (CEA) – Cadarache, DEN/DTN/STCP/LHC, 13108 Saint Paul lez Durance Cedex (France); Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2), UMR7340 CNRS, Aix-Marseille Université, Centrale Marseille, 13451 Marseille Cedex (France); Ricciardi, Guillaume [Alternative Energies and Atomic Energy Commission (CEA) – Cadarache, DEN/DTN/STCP/LHC, 13108 Saint Paul lez Durance Cedex (France); Viazzo, Stéphane [Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2), UMR7340 CNRS, Aix-Marseille Université, Centrale Marseille, 13451 Marseille Cedex (France)

2017-06-15

Highlights: • Complex geometry inside a PWR fuel assembly is simulated using simplified 3D models. • Structured meshes are generated as far as possible. • Fluctuating hydrodynamic and wall pressure field are analyzed using LES. • Comparative studies between square spacer grid, circular spacer grid and mixing vanes are presented. • Simulations are compared with experimental data. - Abstract: Flow-induced vibrations in a pressurized water reactor (PWR) core can cause fretting wear in fuel rods. These vibrations can compromise safety of a nuclear reactor. So, it is necessary to know the random fluctuating forces acting on the rods which cause these vibrations. In this paper, simplified 3D models like square spacer grid, circular spacer grid and symmetric mixing vanes have been used inside an annular pipe. Hydrodynamic and wall pressure characteristics are evaluated using large eddy simulations (LES). Structured meshes are generated as far as possible. Simulations are compared with an experiment. Results show that the grid and vanes have a combined effect: grid accelerates the flow whereas the vanes contribute to the swirl structures. Spectral analysis of the simulations illustrate vortex shedding phenomenon in the wake of spacer grids. This initial study opens up interesting perspectives towards improving the modeling strategy and understanding the complex phenomenon inside a PWR core.

Comparative study of the contribution of various PWR spacer grid components to hydrodynamic and wall pressure characteristics

International Nuclear Information System (INIS)

Bhattacharjee, Saptarshi; Ricciardi, Guillaume; Viazzo, Stéphane

2017-01-01

Highlights: • Complex geometry inside a PWR fuel assembly is simulated using simplified 3D models. • Structured meshes are generated as far as possible. • Fluctuating hydrodynamic and wall pressure field are analyzed using LES. • Comparative studies between square spacer grid, circular spacer grid and mixing vanes are presented. • Simulations are compared with experimental data. - Abstract: Flow-induced vibrations in a pressurized water reactor (PWR) core can cause fretting wear in fuel rods. These vibrations can compromise safety of a nuclear reactor. So, it is necessary to know the random fluctuating forces acting on the rods which cause these vibrations. In this paper, simplified 3D models like square spacer grid, circular spacer grid and symmetric mixing vanes have been used inside an annular pipe. Hydrodynamic and wall pressure characteristics are evaluated using large eddy simulations (LES). Structured meshes are generated as far as possible. Simulations are compared with an experiment. Results show that the grid and vanes have a combined effect: grid accelerates the flow whereas the vanes contribute to the swirl structures. Spectral analysis of the simulations illustrate vortex shedding phenomenon in the wake of spacer grids. This initial study opens up interesting perspectives towards improving the modeling strategy and understanding the complex phenomenon inside a PWR core.

Hybrid Thermochemical/Biological Processing

Science.gov (United States)

Brown, Robert C.

The conventional view of biorefineries is that lignocellulosic plant material will be fractionated into cellulose, hemicellulose, lignin, and terpenes before these components are biochemically converted into market products. Occasionally, these plants include a thermochemical step at the end of the process to convert recalcitrant plant components or mixed waste streams into heat to meet thermal energy demands elsewhere in the facility. However, another possibility for converting high-fiber plant materials is to start by thermochemically processing it into a uniform intermediate product that can be biologically converted into a bio-based product. This alternative route to bio-based products is known as hybrid thermochemical/biological processing. There are two distinct approaches to hybrid processing: (a) gasification followed by fermentation of the resulting gaseous mixture of carbon monoxide (CO), hydrogen (H2), and carbon dioxide (CO2) and (b) fast pyrolysis followed by hydrolysis and/or fermentation of the anhydrosugars found in the resulting bio-oil. This article explores this "cart before the horse" approach to biorefineries.

Numerical Simulation on the Performance of a Mixed-Flow Pump under Various Casing Structures

Directory of Open Access Journals (Sweden)

Wu Dazhuan

2013-01-01

Full Text Available With regard to the reactor coolant pump and high flow-rate circulating pump, the requirements on the compactness of the structure, safety, and hydraulic performance are particularly important. Thus, the mixed-flow pump with cylindrical casing is adopted in some occasions. Due to the different characteristics between the special cylindrical casing and the common pump casing, the influence of the special casing on a mixed-flow pump characteristics was numerically investigated to obtain better performance and flow structure in the casing. The results show that the models with cylindrical casing have much worse head and efficiency characteristics than the experimental model, and this is caused by the flow in the pump casing. By moving the guide vanes half inside the pump casing, the efficiency gets improved while the low pressure zone at the corner of outlet pipe and pump casing disappeared. When the length of pump casing increases from the size equal to the diameter of outlet pipe to that larger than it, the efficiency drops obviously and the flow field in the outlet pipe improved without curved flow. In addition, the length of the pump casing has greater impacts on the pump performance than the radius of it.

Microlearning mApp raises health competence: hybrid service design.

Science.gov (United States)

Simons, Luuk P A; Foerster, Florian; Bruck, Peter A; Motiwalla, Luvai; Jonker, Catholijn M

Work place health support interventions can help support our aging work force, with mApps offering cost-effectiveness opportunities. Previous research shows that health support apps should offer users enough newness and relevance each time they are used. Otherwise the 'eHealth law of attrition' applies: 90 % of users are lost prematurely. Our research study builds on this prior research with further investigation on whether a mobile health quiz provides added value for users within a hybrid service mix and whether it promotes long term health? We developed a hybrid health support intervention solution that uses a mix of electronic and physical support services for improving health behaviours, including a mobile micro-learning health quiz. This solution was evaluated in a multiple-case study at three work sites with 86 users. We find that both our mobile health quiz and the overall hybrid solution contributed to improvements in health readiness, -behaviour and -competence. Users indicated that the micro-learning health quiz courses provided new and relevant information. Relatively high utilization rates of the health quiz were observed. Participants indicated that health insights were given that directly influenced every day health perceptions, -choices, coping and goal achievement strategies, plus motivation and self-norms. This points to increased user health self-management competence. Moreover, even after 10 months they indicated to still have improved health awareness, -motivation and -behaviours (food, physical activity, mental recuperation). A design analysis was conducted regarding service mix efficacy; the mobile micro-learning health quiz helped fulfil a set of key requirements that exist for designing ICT-enabled lifestyle interventions, largely in the way it was anticipated.

A novel extended architecture with 4 6·6 4 topology based on mixed-valence Wells-Dawson arsenotungstate and mixed-ligand Cu(I) units

Science.gov (United States)

Tong, Ruizhan; Ren, Xiaoyu; Li, Zuoxi; Liu, Bin; Hu, Huaiming; Xue, Ganglin; Fu, Feng; Wang, Jiwu

2010-09-01

A novel inorganic-organic hybrid compound based on mixed-valence Wells-Dawson arsenotungstate and mixed-ligand Cu(I) units, Cu 8I(imi) 4(bpy) 6(H 2O)[As 2VW 2VW 16VlO 62]·2H 2O ( 1) (bpy=4,4'-bipydine; imi=imidazole), has been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, luminescent spectrum and single crystal X-ray diffraction. Single-crystal X-ray diffraction revealed that four terminal and three bridging oxygen atoms of the Wells-Dawson cluster are coordinated to Cu(I) ions and form an unprecedented hepta-supporting polyoxometalate. The functionalized arsenotungstates are further connected by two kinds of tridentate linkers, Imi-Cu-(bpy)-Cu-(bpy)-Cu-(bpy)-Cu-Imi and Imi-Cu-(bpy)-Cu-(bpy)-Cu-H 2O, to construct a 3D framework with 4 6·6 4 topology. The hybrid material has an intense emission at about 397 nm.

Active Flow Control in a Radial Vaned Diffuser for Surge Margin Improvement: A Multislot Suction Strategy

Directory of Open Access Journals (Sweden)

Aurélien Marsan

2017-01-01

Full Text Available This work is the final step of a research project that aims at evaluating the possibility of delaying the surge of a centrifugal compressor stage using a boundary-layer suction technique. It is based on Reynolds-Averaged Navier-Stokes numerical simulations. Boundary-layer suction is applied within the radial vaned diffuser. Previous work has shown the necessity to take into account the unsteady behavior of the flow when designing the active flow control technique. In this paper, a multislot strategy is designed according to the characteristics of the unsteady pressure field. Its implementation results in a significant increase of the stable operating range predicted by the unsteady RANS numerical model. A hub-corner separation still exists further downstream in the diffuser passage but does not compromise the stability of the compressor stage.

Numerical Study of Compact Plate-Fin Heat Exchanger for Rotary-Vane Gas Refrigeration Machine

Directory of Open Access Journals (Sweden)

V. V. Trandafilov

2017-10-01

Full Text Available Plate-fin heat exchangers are widely used in refrigeration technique. They are popular because of their compactness and excellent heat transfer performance. Here we present a numerical model for the development, research and optimization of a plate-fin heat exchanger for a rotary-vane gas refrigeration machine. The method of analysis by graphic method of plate - fin heat exchanger is proposed. The model describes the effects of secondary parameters such as axial thermal conductivity through a metal matrix of the heat exchanger. The influence of geometric parameters and heat transfer coefficient is studied. Graphs of dependences of length, efficiency of a fin and pressure drop in a heat exchanger on the thickness of the fin and the number of fins per meter are obtained. To analyze the results of numerical simulation, the heat exchanger was designed in the Aspen HYSYS program. The simulation results show that the total deviation from the proposed numerical model is not more than 15%. 

Photoemission studies of mixed valent systems

International Nuclear Information System (INIS)

Parks, R.D.; Raaen, S.; denBoer, M.L.; Williams, G.P.

1984-01-01

Photoemission spectroscopy has been used to study a number of aspects of the mixed valent state (corresponding to non-integral 4f occupation) in rare earth systems. Deep core photoemission (e.g., from 3d or 4d levels) allows the measurement of the 4f occupancy and surface valence shifts, and, as well, the indirect measurement of the effect of solid state environment on the energy of hybridization between 4f electrons and conduction electrons. 4f-Derived photoemission has been used to study surface valance and chemical shifts and to infer the nature of the mixed valent ground state. A combination of 4f-derived photoemission and add-electron spectroscopy provides a measurement of the rf Coulomb correlation energy, an important parameter in the mixed valent problem. A review of these approaches will be presented, with emphasis on Ce-based systems, whose behavior falls outside the usual description of 4f-unstable systems

The effect of epoxidized soybean oil on mechanical and rheological properties of poly(butylene succinate)/lignin via vane extruder

Science.gov (United States)

Liu, Huanyu; Huang, Zhaoxia; Qu, Jinping; Meng, Cong

2016-03-01

Epoxidized Soybean Oil (ESO) have been used as the compatilizer in the Poly (butylene succinate)/lignin (PBS/lignin) composites. Compatibilized composites were fabricated by a novel vane extruder (VE) which can generate global and dynamic elongational flow. The effects of ESO on the mechanical, rheological properties and morphology of PBS/lignin were studied. The results indicated that the use of ESO had plasticizing effect on the matrix PBS while the addition reduced tensile strength. From SEM micrographs it could be clearly observed that there was a better interfacial adhesion between lignin and matrix. Meanwhile, rheological tests showed the incorporation of ESO improved its Newtonian behavior and can enhance PBS's flexibility.

Nanocomposite-Based Bulk Heterojunction Hybrid Solar Cells

Directory of Open Access Journals (Sweden)

Bich Phuong Nguyen

2014-01-01

Full Text Available Photovoltaic devices based on nanocomposites composed of conjugated polymers and inorganic nanocrystals show promise for the fabrication of low-cost third-generation thin film photovoltaics. In theory, hybrid solar cells can combine the advantages of the two classes of materials to potentially provide high power conversion efficiencies of up to 10%; however, certain limitations on the current within a hybrid solar cell must be overcome. Current limitations arise from incompatibilities among the various intradevice interfaces and the uncontrolled aggregation of nanocrystals during the step in which the nanocrystals are mixed into the polymer matrix. Both effects can lead to charge transfer and transport inefficiencies. This paper highlights potential strategies for resolving these obstacles and presents an outlook on the future directions of this field.

Origin of Reversible Photoinduced Phase Separation in Hybrid Perovskites

Science.gov (United States)

Bischak, Connor G.; Hetherington, Craig L.; Wu, Hao; Aloni, Shaul; Ogletree, D. Frank; Limmer, David T.; Ginsberg, Naomi S.

2017-02-01

Nonequilibrium processes occurring in functional materials can significantly impact device efficiencies and are often difficult to characterize due to the broad range of length and time scales involved. In particular, mixed halide hybrid perovskites are promising for optoelectronics, yet the halides reversibly phase separate when photo-excited, significantly altering device performance. By combining nanoscale imaging and multiscale modeling, we elucidate the mechanism underlying this phenomenon, demonstrating that local strain induced by photo-generated polarons promotes halide phase separation and leads to nucleation of light-stabilized iodide-rich clusters. This effect relies on the unique electromechanical properties of hybrid materials, characteristic of neither their organic nor inorganic constituents alone. Exploiting photo-induced phase separation and other nonequilibrium phenomena in hybrid materials, generally, could enable new opportunities for expanding the functional applications in sensing, photoswitching, optical memory, and energy storage.

HSimulator: Hybrid Stochastic/Deterministic Simulation of Biochemical Reaction Networks

Directory of Open Access Journals (Sweden)

Luca Marchetti

2017-01-01

Full Text Available HSimulator is a multithread simulator for mass-action biochemical reaction systems placed in a well-mixed environment. HSimulator provides optimized implementation of a set of widespread state-of-the-art stochastic, deterministic, and hybrid simulation strategies including the first publicly available implementation of the Hybrid Rejection-based Stochastic Simulation Algorithm (HRSSA. HRSSA, the fastest hybrid algorithm to date, allows for an efficient simulation of the models while ensuring the exact simulation of a subset of the reaction network modeling slow reactions. Benchmarks show that HSimulator is often considerably faster than the other considered simulators. The software, running on Java v6.0 or higher, offers a simulation GUI for modeling and visually exploring biological processes and a Javadoc-documented Java library to support the development of custom applications. HSimulator is released under the COSBI Shared Source license agreement (COSBI-SSLA.

Separating Bulk and Surface Contributions to Electronic Excited-State Processes in Hybrid Mixed Perovskite Thin Films via Multimodal All-Optical Imaging.

Science.gov (United States)

Simpson, Mary Jane; Doughty, Benjamin; Das, Sanjib; Xiao, Kai; Ma, Ying-Zhong

2017-07-20

A comprehensive understanding of electronic excited-state phenomena underlying the impressive performance of solution-processed hybrid halide perovskite solar cells requires access to both spatially resolved electronic processes and corresponding sample morphological characteristics. Here, we demonstrate an all-optical multimodal imaging approach that enables us to obtain both electronic excited-state and morphological information on a single optical microscope platform with simultaneous high temporal and spatial resolution. Specifically, images were acquired for the same region of interest in thin films of chloride containing mixed lead halide perovskites (CH 3 NH 3 PbI 3-x Cl x ) using femtosecond transient absorption, time-integrated photoluminescence, confocal reflectance, and transmission microscopies. Comprehensive image analysis revealed the presence of surface- and bulk-dominated contributions to the various images, which describe either spatially dependent electronic excited-state properties or morphological variations across the probed region of the thin films. These results show that PL probes effectively the species near or at the film surface.

Numerical investigation on pressure fluctuations in centrifugal compressor with different inlet guide vanes pre-whirl angles

Science.gov (United States)

Wang, Y. C.; Shi, M.; Cao, S. L.; Li, Z. H.

2013-12-01

The pressure fluctuations in a centrifugal compressor with different inlet guide vanes (IGV) pre-whirl angles were investigated numerically, as well as the pre-stress model and static structural of blade. The natural frequency was evaluated by pre-stress model analysis. The results show that, the aero-dynamic pressure acting on blade surface is smaller than rotation pre-stress, which wouldn't result in large deformation of blade. The natural frequencies with rotation pre-stress are slightly higher than without rotation pre-stress. The leading mechanism of pressure fluctuations for normal conditions is the rotor-stator (IGVs) interaction, while is serious flow separations for conditions that are close to surge line. A few frequency components in spectra are close to natural frequency, which possibly result in resonant vibration if amplitude is large enough, which is dangerous for compressor working, and should be avoided.

Hybrid thin films derived from UV-curable acrylate-modified waterborne polyurethane and monodispersed colloidal silica

Directory of Open Access Journals (Sweden)

C. H. Yang

2012-01-01

Full Text Available Hybrid thin films containing nano-sized inorganic domains were synthesized from UV-curable acrylate-modified waterborne polyurethane (WPU-AC and monodispersed colloidal silica with coupling agent. The coupling agent, 3-(trimethoxysilylpropyl methacrylate (MSMA, was bonded onto colloidal silica first, and then mixed with WPU-AC to form a precursor solution. This precursor was spin coated, dried and UV-cured to generate the hybrid films. The silica content in the hybrid thin films was varied from 0 to 30 wt%. Experimental results showed the aggregation of silica particles in the hybrid films. Thus, the silica domain in the hybrid films was varied from 30 to 50 nm by the different ratios of MSMAsilica to WPU-AC. The prepared hybrid films from the crosslinked WPU-AC/MSMA-silica showed much better thermal stability and mechanical properties than pure WPU-AC.

Mixed-hybrid finite element method for the transport equation and diffusion approximation of transport problems; Resolution de l'equation du transport par une methode d'elements finis mixtes-hybrides et approximation par la diffusion de problemes de transport

Energy Technology Data Exchange (ETDEWEB)

Cartier, J

2006-04-15

This thesis focuses on mathematical analysis, numerical resolution and modelling of the transport equations. First of all, we deal with numerical approximation of the solution of the transport equations by using a mixed-hybrid scheme. We derive and study a mixed formulation of the transport equation, then we analyse the related variational problem and present the discretization and the main properties of the scheme. We particularly pay attention to the behavior of the scheme and we show its efficiency in the diffusion limit (when the mean free path is small in comparison with the characteristic length of the physical domain). We present academical benchmarks in order to compare our scheme with other methods in many physical configurations and validate our method on analytical test cases. Unstructured and very distorted meshes are used to validate our scheme. The second part of this thesis deals with two transport problems. The first one is devoted to the study of diffusion due to boundary conditions in a transport problem between two plane plates. The second one consists in modelling and simulating radiative transfer phenomenon in case of the industrial context of inertial confinement fusion. (author)

Hybrid electrospun chitosan-phospholipids nanofibers for transdermal drug delivery.

Science.gov (United States)

Mendes, Ana C; Gorzelanny, Christian; Halter, Natalia; Schneider, Stefan W; Chronakis, Ioannis S

2016-08-20

Chitosan (Ch) polysaccharide was mixed with phospholipids (P) to generate electrospun hybrid nanofibers intended to be used as platforms for transdermal drug delivery. Ch/P nanofibers exibithed average diameters ranging from 248±94nm to 600±201nm, depending on the amount of phospholipids used. Fourier Transformed Infra-Red (FTIR) spectroscopy and Dynamic Light Scattering (DLS) data suggested the occurrence of electrostatic interactions between amine groups of chitosan with the phospholipid counterparts. The nanofibers were shown to be stable for at least 7days in Phosphate Buffer Saline (PBS) solution. Cytotoxicity studies (WST-1 and LDH assays) demonstrated that the hybrid nanofibers have suitable biocompatibility. Fluorescence microscopy, also suggested that L929 cells seeded on top of the CH/P hybrid have similar metabolic activity comparatively to the cells seeded on tissue culture plate (control). The release of curcumin, diclofenac and vitamin B12, as model drugs, from Ch/P hybrid nanofibers was investigated, demonstrating their potential utilization as a transdermal drug delivery system. Copyright © 2016 Elsevier B.V. All rights reserved.

Origin of Reversible Photoinduced Phase Separation in Hybrid Perovskites.

Science.gov (United States)

Bischak, Connor G; Hetherington, Craig L; Wu, Hao; Aloni, Shaul; Ogletree, D Frank; Limmer, David T; Ginsberg, Naomi S

2017-02-08

The distinct physical properties of hybrid organic-inorganic materials can lead to unexpected nonequilibrium phenomena that are difficult to characterize due to the broad range of length and time scales involved. For instance, mixed halide hybrid perovskites are promising materials for optoelectronics, yet bulk measurements suggest the halides reversibly phase separate upon photoexcitation. By combining nanoscale imaging and multiscale modeling, we find that the nature of halide demixing in these materials is distinct from macroscopic phase separation. We propose that the localized strain induced by a single photoexcited charge interacting with the soft, ionic lattice is sufficient to promote halide phase separation and nucleate a light-stabilized, low-bandgap, ∼8 nm iodide-rich cluster. The limited extent of this polaron is essential to promote demixing because by contrast bulk strain would simply be relaxed. Photoinduced phase separation is therefore a consequence of the unique electromechanical properties of this hybrid class of materials. Exploiting photoinduced phase separation and other nonequilibrium phenomena in hybrid materials more generally could expand applications in sensing, switching, memory, and energy storage.

INLAND-COASTAL PHILIPPINE HYBRIDITY: HETEROGLOSSIA IN AGUSAN MANOBO MUSIC AND RITUAL

Directory of Open Access Journals (Sweden)

José S. Buenconsejo

2010-06-01

Full Text Available This article deals with the hybridity of contemporary Agusan Manobo music as evident in its repertory and in the heteroglossia of possession ritual performances, where various archaic and modern speech styles (including song and ritual dance music co-exist. This hybridity is consequent to the history of Agusan Manobo relations with outsiders, especially Visayan-speaking settlers whose markers of group identity have been incorporated into Manobo rites. Such incorporation indicates the Manobo presence to a social world that is characterized by a mix between inland Manobo and coastal Visayan cultures.

Approaches to Mixed Methods Dissemination and Implementation Research: Methods, Strengths, Caveats, and Opportunities.

Science.gov (United States)

Green, Carla A; Duan, Naihua; Gibbons, Robert D; Hoagwood, Kimberly E; Palinkas, Lawrence A; Wisdom, Jennifer P

2015-09-01

Limited translation of research into practice has prompted study of diffusion and implementation, and development of effective methods of encouraging adoption, dissemination and implementation. Mixed methods techniques offer approaches for assessing and addressing processes affecting implementation of evidence-based interventions. We describe common mixed methods approaches used in dissemination and implementation research, discuss strengths and limitations of mixed methods approaches to data collection, and suggest promising methods not yet widely used in implementation research. We review qualitative, quantitative, and hybrid approaches to mixed methods dissemination and implementation studies, and describe methods for integrating multiple methods to increase depth of understanding while improving reliability and validity of findings.

CFD simulation on condensation inside a Hybrid SIT

Energy Technology Data Exchange (ETDEWEB)

Jeon, Byong Guk; Ryu, Sung Uk; Kim, Seok; Euh, Dong Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

The concept of Hybrid Safety Injection Tank system (Hybrid SIT) was proposed by Korea Atomic Energy Research Institute (KAERI) aiming at Advanced Power Reactor Plus. The main advantage of the system is the ready injection of coolant into the reactor coolant system at high pressure. In this paper, a CFD simulation is conducted as a preliminary study. In Hybrid SITs, condensation inside the tank affects its pressure rise and injection time. In an attempt to explore the condensation in detail, we manufactured a dedicated experimental facility for visualization of condensation-induced thermal mixing and conducted a preliminary CFD simulation. Its condensation models were validated first and then computational domain was constructed. The water region was modeled as a solid for stable calculation. The CFD results gave less condensation and excessive pressurization because of lack of steam penetration into the water. In the future, the water region will be modeled as liquid using a VOF model.

Hybrid normed ideal perturbations of n-tuples of operators I

Science.gov (United States)

Voiculescu, Dan-Virgil

2018-06-01

In hybrid normed ideal perturbations of n-tuples of operators, the normed ideal is allowed to vary with the component operators. We begin extending to this setting the machinery we developed for normed ideal perturbations based on the modulus of quasicentral approximation and an adaptation of our non-commutative generalization of the Weyl-von Neumann theorem. For commuting n-tuples of hermitian operators, the modulus of quasicentral approximation remains essentially the same when Cn- is replaced by a hybrid n-tuple Cp1,…- , … , Cpn- , p1-1 + ⋯ + pn-1 = 1. The proof involves singular integrals of mixed homogeneity.

Mixed-μ magnetic levitation for advanced ground transport system

International Nuclear Information System (INIS)

Russell, F.M.

1977-12-01

The possibility of applying the mixed-μ principle for magnetic levitation to ground transport systems is examined. The system is developed specifically for suspension and useful lift to passive weight ratios exceeding 8:1 have been calculated. Application to a hybrid system where conventional wheel drive is used in conjunction with magnetic levitation is explained for urban transport. (author)

Hybrid models for chemical reaction networks: Multiscale theory and application to gene regulatory systems

Science.gov (United States)

Winkelmann, Stefanie; Schütte, Christof

2017-09-01

Well-mixed stochastic chemical kinetics are properly modeled by the chemical master equation (CME) and associated Markov jump processes in molecule number space. If the reactants are present in large amounts, however, corresponding simulations of the stochastic dynamics become computationally expensive and model reductions are demanded. The classical model reduction approach uniformly rescales the overall dynamics to obtain deterministic systems characterized by ordinary differential equations, the well-known mass action reaction rate equations. For systems with multiple scales, there exist hybrid approaches that keep parts of the system discrete while another part is approximated either using Langevin dynamics or deterministically. This paper aims at giving a coherent overview of the different hybrid approaches, focusing on their basic concepts and the relation between them. We derive a novel general description of such hybrid models that allows expressing various forms by one type of equation. We also check in how far the approaches apply to model extensions of the CME for dynamics which do not comply with the central well-mixed condition and require some spatial resolution. A simple but meaningful gene expression system with negative self-regulation is analysed to illustrate the different approximation qualities of some of the hybrid approaches discussed. Especially, we reveal the cause of error in the case of small volume approximations.

Hybrid models for chemical reaction networks: Multiscale theory and application to gene regulatory systems.

Science.gov (United States)

Winkelmann, Stefanie; Schütte, Christof

2017-09-21

Well-mixed stochastic chemical kinetics are properly modeled by the chemical master equation (CME) and associated Markov jump processes in molecule number space. If the reactants are present in large amounts, however, corresponding simulations of the stochastic dynamics become computationally expensive and model reductions are demanded. The classical model reduction approach uniformly rescales the overall dynamics to obtain deterministic systems characterized by ordinary differential equations, the well-known mass action reaction rate equations. For systems with multiple scales, there exist hybrid approaches that keep parts of the system discrete while another part is approximated either using Langevin dynamics or deterministically. This paper aims at giving a coherent overview of the different hybrid approaches, focusing on their basic concepts and the relation between them. We derive a novel general description of such hybrid models that allows expressing various forms by one type of equation. We also check in how far the approaches apply to model extensions of the CME for dynamics which do not comply with the central well-mixed condition and require some spatial resolution. A simple but meaningful gene expression system with negative self-regulation is analysed to illustrate the different approximation qualities of some of the hybrid approaches discussed. Especially, we reveal the cause of error in the case of small volume approximations.

A Game-Theoretic approach to Fault Diagnosis of Hybrid Systems

Directory of Open Access Journals (Sweden)

Davide Bresolin

2011-06-01

Full Text Available Physical systems can fail. For this reason the problem of identifying and reacting to faults has received a large attention in the control and computer science communities. In this paper we study the fault diagnosis problem for hybrid systems from a game-theoretical point of view. A hybrid system is a system mixing continuous and discrete behaviours that cannot be faithfully modeled neither by using a formalism with continuous dynamics only nor by a formalism including only discrete dynamics. We use the well known framework of hybrid automata for modeling hybrid systems, and we define a Fault Diagnosis Game on them, using two players: the environment and the diagnoser. The environment controls the evolution of the system and chooses whether and when a fault occurs. The diagnoser observes the external behaviour of the system and announces whether a fault has occurred or not. Existence of a winning strategy for the diagnoser implies that faults can be detected correctly, while computing such a winning strategy corresponds to implement a diagnoser for the system. We will show how to determine the existence of a winning strategy, and how to compute it, for some decidable classes of hybrid automata like o-minimal hybrid automata.

Enhancement of exchange coupling interaction of NdFeB/MnBi hybrid magnets

Science.gov (United States)

Nguyen, Truong Xuan; Nguyen, Khanh Van; Nguyen, Vuong Van

2018-03-01

MnBi ribbons were fabricated by melt - spinning with subsequent annealing. The MnBi ribbons were ground and mixed with NdFeB commercial Magnequench powders (MQA). The hybrid powder mixtures were subjected thrice to the annealing and ball-milling route. The hybrid magnets (100 - x)NdFeB/xMnBi, x=0, 30, 40, 50 and 100 wt% were in-mold aligned in an 18 kOe magnetic field and warm compacted at 290 °C by 2000 psi uniaxial pressure for 10 min. An enhancement of the exchange coupling of NdFeB/MnBi hybrid magnets was obtained by optimizing the magnets' microstructures via annealing and ball-milling processes. The magnetic properties of prepared NdFeB/MnBi hybrid magnets were studied and discussed in details.

Multiple and asymmetrical origin of polyploid dog rose hybrids (Rosa L. sect. Caninae (DC.) Ser.) involving unreduced gametes.

Science.gov (United States)

Herklotz, V; Ritz, C M

2017-08-01

Polyploidy and hybridization are important factors for generating diversity in plants. The species-rich dog roses ( Rosa sect. Caninae ) originated by allopolyploidy and are characterized by unbalanced meiosis producing polyploid egg cells (usually 4 x ) and haploid sperm cells (1 x ). In extant natural stands species hybridize spontaneously, but the extent of natural hybridization is unknown. The aim of the study was to document the frequency of reciprocal hybridization between the subsections Rubigineae and Caninae with special reference to the contribution of unreduced egg cells (5 x ) producing 6 x offspring after fertilization with reduced (1 x ) sperm cells. We tested whether hybrids arose by independent multiple events or via a single or few incidences followed by a subsequent spread of hybrids. Population genetics of 45 mixed stands of dog roses across central and south-eastern Europe were analysed using microsatellite markers and flow cytometry. Hybrids were recognized by the presence of diagnostic alleles and multivariate statistics were used to display the relationships between parental species and hybrids. Among plants classified to subsect. Rubigineae , 32 % hybridogenic individuals were detected but only 8 % hybrids were found in plants assigned to subsect. Caninae . This bias between reciprocal crossings was accompanied by a higher ploidy level in Rubigineae hybrids, which originated more frequently by unreduced egg cells. Genetic patterns of hybrids were strongly geographically structured, supporting their independent origin. The biased crossing barriers between subsections are explained by the facilitated production of unreduced gametes in subsect. Rubigineae . Unreduced egg cells probably provide the highly homologous chromosome sets required for correct chromosome pairing in hybrids. Furthermore, the higher frequency of Rubigineae hybrids is probably influenced by abundance effects because the plants of subsect. Caninae are much more abundant

Protocol Design and Performance Analysis of Multiuser Mixed RF and Hybrid FSO/RF Relaying With Buffers

KAUST Repository

Al-Eryani, Yasser F.

2018-03-07

In this paper, a multiuser mixed radio frequency (RF) and hybrid free-space optical (FSO)/RF system is considered, where multiple mobile users transmit their data to an intermediate decode-and-forward relay node through RF links using a virtual multiple-input multipleoutput (MIMO) system, and the relay node forwards the multiplexed data of all users through a FSO link that is supported by a RF MIMO backup system to the destination. The relay node is equipped with a buffer in the physical layer for temporal storage of the users\\' data until the best channel conditions at the relay-destination link aremet. For this communication setup, we first propose a transmission protocol that achieves a multiplexing gain through a virtual MIMO system. After that, we derive closed-form expressions for the end-to-end outage probability, asymptotic outage probability, average symbol error rate, and the ergodic capacity when considering the delay-tolerant (finite buffer size) scenario. The results show that buffering in the physical layer provides a significant enhancement to the system performance (outage, error rate, and ergodic capacity). It is also found that pointing error and severe weather turbulence conditions become more tolerable with the existence of the relay\\'s buffer and RF backup link (in the second hop). In addition, the proposed virtual MIMO scheme shows a significant performance enhancement at a high number of receiving antennas, which introduces potential lowcomplexity diversity gain-based massive MIMO schemes.

Protocol Design and Performance Analysis of Multiuser Mixed RF and Hybrid FSO/RF Relaying With Buffers

KAUST Repository

Al-Eryani, Yasser F.; Salhab, Anas; Zummo, Salam A.; Alouini, Mohamed-Slim

2018-01-01

In this paper, a multiuser mixed radio frequency (RF) and hybrid free-space optical (FSO)/RF system is considered, where multiple mobile users transmit their data to an intermediate decode-and-forward relay node through RF links using a virtual multiple-input multipleoutput (MIMO) system, and the relay node forwards the multiplexed data of all users through a FSO link that is supported by a RF MIMO backup system to the destination. The relay node is equipped with a buffer in the physical layer for temporal storage of the users' data until the best channel conditions at the relay-destination link aremet. For this communication setup, we first propose a transmission protocol that achieves a multiplexing gain through a virtual MIMO system. After that, we derive closed-form expressions for the end-to-end outage probability, asymptotic outage probability, average symbol error rate, and the ergodic capacity when considering the delay-tolerant (finite buffer size) scenario. The results show that buffering in the physical layer provides a significant enhancement to the system performance (outage, error rate, and ergodic capacity). It is also found that pointing error and severe weather turbulence conditions become more tolerable with the existence of the relay's buffer and RF backup link (in the second hop). In addition, the proposed virtual MIMO scheme shows a significant performance enhancement at a high number of receiving antennas, which introduces potential lowcomplexity diversity gain-based massive MIMO schemes.

A mix-and-read drop-based in vitro two-hybrid method for screening high-affinity peptide binders

Science.gov (United States)

Cui, Naiwen; Zhang, Huidan; Schneider, Nils; Tao, Ye; Asahara, Haruichi; Sun, Zhiyi; Cai, Yamei; Koehler, Stephan A.; de Greef, Tom F. A.; Abbaspourrad, Alireza; Weitz, David A.; Chong, Shaorong

2016-01-01

Drop-based microfluidics have recently become a novel tool by providing a stable linkage between phenotype and genotype for high throughput screening. However, use of drop-based microfluidics for screening high-affinity peptide binders has not been demonstrated due to the lack of a sensitive functional assay that can detect single DNA molecules in drops. To address this sensitivity issue, we introduced in vitro two-hybrid system (IVT2H) into microfluidic drops and developed a streamlined mix-and-read drop-IVT2H method to screen a random DNA library. Drop-IVT2H was based on the correlation between the binding affinity of two interacting protein domains and transcriptional activation of a fluorescent reporter. A DNA library encoding potential peptide binders was encapsulated with IVT2H such that single DNA molecules were distributed in individual drops. We validated drop-IVT2H by screening a three-random-residue library derived from a high-affinity MDM2 inhibitor PMI. The current drop-IVT2H platform is ideally suited for affinity screening of small-to-medium-sized libraries (103–106). It can obtain hits within a single day while consuming minimal amounts of reagents. Drop-IVT2H simplifies and accelerates the drop-based microfluidics workflow for screening random DNA libraries, and represents a novel alternative method for protein engineering and in vitro directed protein evolution. PMID:26940078

Numerical investigation on pressure fluctuations in centrifugal compressor with different inlet guide vanes pre-whirl angles

International Nuclear Information System (INIS)

Wang, Y C; Shi, M; Cao, S L; Li, Z H

2013-01-01

The pressure fluctuations in a centrifugal compressor with different inlet guide vanes (IGV) pre-whirl angles were investigated numerically, as well as the pre-stress model and static structural of blade. The natural frequency was evaluated by pre-stress model analysis. The results show that, the aero-dynamic pressure acting on blade surface is smaller than rotation pre-stress, which wouldn't result in large deformation of blade. The natural frequencies with rotation pre-stress are slightly higher than without rotation pre-stress. The leading mechanism of pressure fluctuations for normal conditions is the rotor-stator (IGVs) interaction, while is serious flow separations for conditions that are close to surge line. A few frequency components in spectra are close to natural frequency, which possibly result in resonant vibration if amplitude is large enough, which is dangerous for compressor working, and should be avoided

Hybrid Semantics of Stochastic Programs with Dynamic Reconfiguration

Directory of Open Access Journals (Sweden)

Alberto Policriti

2009-10-01

Full Text Available We begin by reviewing a technique to approximate the dynamics of stochastic programs --written in a stochastic process algebra-- by a hybrid system, suitable to capture a mixed discrete/continuous evolution. In a nutshell, the discrete dynamics is kept stochastic while the continuous evolution is given in terms of ODEs, and the overall technique, therefore, naturally associates a Piecewise Deterministic Markov Process with a stochastic program. The specific contribution in this work consists in an increase of the flexibility of the translation scheme, obtained by allowing a dynamic reconfiguration of the degree of discreteness/continuity of the semantics. We also discuss the relationships of this approach with other hybrid simulation strategies for biochemical systems.

Gas-Transport-Property Performance of Hybrid Carbon Molecular Sieve−Polymer Materials

KAUST Repository

Das, Mita

2010-10-06

High-performance hybrid materials using carbon molecular sieve materials and 6FDA-6FpDA were produced. A detailed analysis of the effects of casting processes and the annealing temperature is reported. Two existing major obstacles, sieve agglomeration and residual stress, were addressed in this work, and subsequently a new membrane formation technique was developed to produce high-performing membranes. The successfully improved interfacial region of the hybrid membranes allows the sieves to increase the selectivity of the membranes above the neat polymer properties. Furthermore, an additional performance enhancement was seen with increased sieve loading in the hybrid membranes, leading to an actual performance above the upper bound for pure polymer membranes. The membranes were also tested under a mixed-gas environment, which further demonstrated promising results. © 2010 American Chemical Society.

Characterization of a silica-PVA hybrid for high density and stable silver dissolution

Energy Technology Data Exchange (ETDEWEB)

Dorin, Bryce, E-mail: bryce.dorin@postgrad.manchester.ac.uk [The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); School of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Zhu, Guangyu, E-mail: g.zhu@liverpool.ac.uk [Lairdside Laser Engineering Centre, The University of Liverpool, Campbeltown Road, Merseyside, CH41 9HP (United Kingdom); Parkinson, Patrick, E-mail: patrick.parkinson@manchester.ac.uk [The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Perrie, Walter, E-mail: wpfemto1@liverpool.ac.uk [Lairdside Laser Engineering Centre, The University of Liverpool, Campbeltown Road, Merseyside, CH41 9HP (United Kingdom); Benyezzar, Med, E-mail: med.benyezzar@manchester.ac.uk [The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Scully, Patricia, E-mail: patricia.scully@manchester.ac.uk [The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); School of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom)

2016-07-01

A silica and polyvinyl alcohol (PVA) hybrid material mixed with a high density of silver ions is synthesised and characterized in this work. The hybrid material can be cast into thick films, which we determined to be homogeneous using Raman spectroscopy. We observed that the silver ions remain stable in the material over time and at temperatures of 100 °C, which represents a marked improvement over previous solid solutions of silver. Differential scanning calorimetry and thermogravimetric analysis indicate the rapid activation of silver at 173 °C, resulting in a dense formation of silver nanoparticles within the hybrid. The activation of silver was also demonstrated in 3-dimensional geometries using femtosecond duration laser pulses. These results illustrate the silica-PVA hybrid is an attractive material for developing silver-insulator composites. - Highlights: • A novel PVA-silica hybrid is developed for silver ion dissolution. • The hybrid exhibits a high silver saturation point and good silver stability. • Heating and laser irradiation are capable of converting the silver ions to metal. • The hybrid material enables the fabrication of 3D metal-insulator composites.

Hybrid electrospun chitosan-phospholipids nanofibers for transdermal drug delivery

DEFF Research Database (Denmark)

Mendes, Ana Carina Loureiro; Gorzelanny, Christian; Halter, Natalia

2016-01-01

Chitosan (Ch) polysaccharide was mixed with phospholipids (P) to generate electrospun hybrid nanofibers intended to be used as platforms for transdermal drug delivery. Ch/P nanofibers exibithed average diameters ranging from 248 +/- 94 nm to 600 +/- 201 nm, depending on the amount of phospholipids...... used. Fourier Transformed Infra-Red (FTIR) spectroscopy and Dynamic Light Scattering (DLS) data suggested the occurrence of electrostatic interactions between amine groups of chitosan with the phospholipid counterparts. The nanofibers were shown to be stable for at least 7 days in Phosphate Buffer...... culture plate (control). The release of curcumin, diclofenac and vitamin B12, as model drugs, from Ch/P hybrid nanofibers was investigated, demonstrating their potential utilization as a transdermal drug delivery system....

The ecology of white-handed and pileated gibbons in a zone of overlap and hybridization in Thailand.

Science.gov (United States)

Asensio, Norberto; José-Domínguez, Juan Manuel; Kongrit, Chalita; Brockelman, Warren Y

2017-08-01

The study of related species in contact zones can elucidate what factors mediate species coexistence and geographical distributions. We investigated niche overlap and group interactions of two gibbon species and their hybrids co-occurring in a zone of overlap and hybridization. The location, composition and behavior of white-handed, pileated, and mixed-species gibbon groups were studied by following them during 31 consecutive months in a relatively large part of the contact zone. Twenty groups of white-handed gibbon were mapped followed by nine groups of pileated gibbons and five mixed-species groups. White-handed, pileated and mixed-species groups had similar sizes and composition, ate a high proportion of fruits, shared a large number of species in their diets, and presented similar habitat preferences. Group home range sizes did not differ between species and overlapped little with neighboring groups irrespective of species, and intraspecific and interspecific encounter rates were similar. Ecological similarities support that competition between the gibbon species exists and takes the form of interspecific territoriality. However, we could not find any clear mechanism of niche partitioning favoring coexistence between species. Our findings suggest that the contact zone is unstable and is maintained by dispersal inward from groups of the parental species. The relatively low numbers of mixed-species groups and hybrids found suggests a high degree of premating reproductive isolation, perhaps mediated by interspecific miscommunication. The existence of hybrids and backcrosses potentially undetectable from phenotypic characters alone raises the possibility of more widespread introgression than has been evident. Hence, while interspecific territoriality should reduce the rate of gene transfer, it would not necessarily present a barrier to introgression into contiguous populations of the opposite species. © 2017 Wiley Periodicals, Inc.

Mixed-hybrid finite element method for the transport equation and diffusion approximation of transport problems; Resolution de l'equation du transport par une methode d'elements finis mixtes-hybrides et approximation par la diffusion de problemes de transport

Energy Technology Data Exchange (ETDEWEB)

Cartier, J

2006-04-15

This thesis focuses on mathematical analysis, numerical resolution and modelling of the transport equations. First of all, we deal with numerical approximation of the solution of the transport equations by using a mixed-hybrid scheme. We derive and study a mixed formulation of the transport equation, then we analyse the related variational problem and present the discretization and the main properties of the scheme. We particularly pay attention to the behavior of the scheme and we show its efficiency in the diffusion limit (when the mean free path is small in comparison with the characteristic length of the physical domain). We present academical benchmarks in order to compare our scheme with other methods in many physical configurations and validate our method on analytical test cases. Unstructured and very distorted meshes are used to validate our scheme. The second part of this thesis deals with two transport problems. The first one is devoted to the study of diffusion due to boundary conditions in a transport problem between two plane plates. The second one consists in modelling and simulating radiative transfer phenomenon in case of the industrial context of inertial confinement fusion. (author)

Impact Resistance of Recycled Aggregate Concrete with Single and Hybrid Fibers

Directory of Open Access Journals (Sweden)

Ismail Sallehan

2016-01-01

Full Text Available This paper presents a recycled aggregate concrete (RAC mix that has been modified by adding treated recycled concrete aggregate (RCA and various types of fiber-reinforced systems. The effectiveness of these modifications in terms of energy absorption and impact resistance was evaluated and compared with that of the corresponding regular concrete, as well as with unmodified RAC specimens. Results clearly indicate that although modification of the RAC mix with treated RCA significantly enhances the impact resistance of RAC, further diversification with additional fiber, particularly those in hybrid form, can optimize the results.

Preparation and Characterization of Graphene-Based Magnetic Hybrid Nano composite

International Nuclear Information System (INIS)

Jashiela Wani Jusin; Madzlan Aziz

2016-01-01

Graphene-based magnetic hybrid nano composite has the advantage of exhibiting better performance as platform or supporting materials to develop novel properties of composite by increasing selectivity of the targeted adsorbate. The hybrid nano material was prepared by mixing and hydrolysing iron (II) and iron (III) salt precursors in the presence of GO dispersion through coprecipitation method followed by in situ chemical reduction of GO. The effect of weight loading ratio of Fe to GO (4:1, 2.5:1, 1:1 and 1:4) on structural properties of the hybrid nano materials was investigated. The presence of characteristic peaks in FTIR spectra indicated that GO has been successfully oxidized from graphite while the decrease in oxygenated functional groups and peaks intensity evidenced the formation of hybrid nano materials through the subsequent reduction process. The presence of characteristic peaks in XRD pattern denoted that magnetite nanoparticles disappeared at higher loading of GO. TEM micrograph showed that the best distribution of iron oxide particles on the surface of hybrid nano material occurred when the loading ratio of Fe to GO was fixed at 2:5 to 1. The reduced graphene oxide (RGO) sheets in the hybrid materials showed less wrinkled sheet like structure compared to GO due to exfoliation and reduction process during the synthesis. The layered morphology of GO degrades at higher concentrations of iron oxide. (author)

Sol-gel Process in Preparation of Organic-inorganic Hybrid Materials

Directory of Open Access Journals (Sweden)

Macan, J

2008-07-01

Full Text Available Organic-inorganic hybrid materials are a sort of nanostructured material in which the organic and inorganic phases are mixed at molecular level. The inorganic phase in hybrid materials is formed by the sol-gel process, which consists of reactions of hydrolysis and condensation of metal (usually silicon alkoxides. Flexibility of sol-gel process enables creation of hybrid materials with varying organic and inorganic phases in different ratios, and consequently fine-tuning of their properties. In order to obtain true hybrid materials, contact between the phases should be at molecular level, so phase separation between thermodynamically incompatible organic and inorganic phases has to be prevented. Phase interaction can be improved by formation of hydrogen or covalent bonds between them during preparation of hybrid materials. Covalent bond can be introduced by organically modified silicon alkoxides containing a reactive organic group (substituent capable of reacting with the organic phase. In order to obtain hybrid materials with desired structures, a detailed knowledge of hydrolysis and condensation mechanism is necessary. The choice of catalyst, whether acid or base, has the most significant influence on the structure of the inorganic phase. Other important parameters are alkoxide concentration, water: alkoxide ratio, type of alkoxide groups, solvent used, temperature, purity of chemicals used, etc. Hydrolysis and condensation of organically modified silicon alkoxides are additionally influenced by nature and size of the organic supstituent.

Surface Temperature Measurements from a Stator Vane Doublet in a Turbine Engine Afterburner Flame Using a YAG:Tm Thermographic Phosphor

Science.gov (United States)

Eldridge, J. I.; Walker, D. G.; Gollub, S. L.; Jenkins, T. P.; Allison, S. W.

2015-01-01

Luminescence-based surface temperature measurements were obtained from a YAG:Tm-coated stator vane doublet exposed to the afterburner flame of a J85 test engine at University of Tennessee Space Institute (UTSI). The objective of the testing was to demonstrate that reliable surface temperatures based on luminescence decay of a thermographic phosphor producing short-wavelength emission could be obtained from the surface of an actual engine component in a high gas velocity, highly radiative afterburner flame environment. YAG:Tm was selected as the thermographic phosphor for its blue emission at 456 nm (1D23F4 transition) and UV emission at 365 nm (1D23H6 transition) because background thermal radiation is lower at these wavelengths, which are shorter than those of many previously used thermographic phosphors. Luminescence decay measurements were acquired using a probe designed to operate in the afterburner flame environment. The probe was mounted on the sidewall of a high-pressure turbine vane doublet from a Honeywell TECH7000 turbine engine coated with a standard electron-beam physical vapor deposited (EB-PVD) 200-m-thick TBC composed of yttria-stabilized zirconia (YSZ) onto which a 25-m-thick YAG:Tm thermographic phosphor layer was deposited by solution precursor plasma spray (SPPS). Spot temperature measurements were obtained by measuring luminescence decay times at different afterburner power settings and then converting decay time to temperature via calibration curves. Temperature measurements using the decays of the 456 and 365 nm emissions are compared. While successful afterburner environment measurements were obtained to about 1300C with the 456 nm emission, successful temperature measurements using the 365 nm emission were limited to about 1100C due to interference by autofluorescence of probe optics at short decay times.

Solution processeable organic-inorganic hybrids based on pyrene functionalized mixed cubic silsesquioxanes as emitters in OLEDs

KAUST Repository

Yang, Xiaohui

2012-01-01

Traditional materials for application in organic light emitting diodes (OLEDs) are primarily based on small molecules and polymers, with much fewer examples of intermediate molecular weight materials. Our interest lies in this intermediate molecular weight range, specifically in hybrids based on 3-dimensional silsesquioxane (SSQ) cores that represents a new class of versatile materials for application in solution processable OLEDs. We report here various SSQ based hybrids that are easily prepared in one high-yield step from the Heck coupling of commercially available 1-bromopyrene, and 1-bromo-4-heptylbenzene with octavinyl-T8-SSQ, and a mixture of octavinyl-T8-, decavinyl-T10- and dodecavinyl-T12-SSQ. The resulting materials offer numerous advantages for OLEDs including amorphous properties, high-glass-transition temperatures (T g), low polydispersity, solubility in common solvents, and high purity via column chromatography. Solution processed OLEDs prepared from the SSQ hybrids provide sky-blue emission with external quantum efficiencies and current efficiencies of 3.64% and 9.56 cd A -1 respectively. © 2012 The Royal Society of Chemistry.

Preparation of hybrid biomaterials for bone tissue engineering

Directory of Open Access Journals (Sweden)

Vilma Conceição Costa

2007-03-01

Full Text Available Tissue engineering has evolved from the use of biomaterials for bone substitution that fulfill the clinical demands of biocompatibility, biodegradability, non-immunogeneity, structural strength and porosity. Porous scaffolds have been developed in many forms and materials, but few reached the need of adequate physical, biological and mechanical properties. In the present paper we report the preparation of hybrid porous polyvinyl alcohol (PVA/bioactive glass through the sol-gel route, using partially and fully hydrolyzed polyvinyl alcohol, and perform structural characterization. Hybrids containing PVA and bioactive glass with composition 58SiO2-33CaO-9P2O5 were synthesized by foaming a mixture of polymer solution and bioactive glass sol-gel precursor solution. Sol-gel solution was prepared from mixing tetraethoxysilane (TEOS, triethylphosphate (TEP, and calcium chloride as chemical precursors. The hybrid composites obtained after aging and drying at low temperature were chemically and morphologically characterized through infrared spectroscopy and scanning electron microscopy. The degree of hydrolysis of PVA, concentration of PVA solution and different PVA-bioglass composition ratios affect the synthesis procedure. Synthesis parameters must be very well combined in order to allow foaming and gelation. The hybrid scaffolds obtained exhibited macroporous structure with pore size varying from 50 to 600 µm.

A Generalized Hybrid Multiscale Modeling Approach for Flow and Reactive Transport in Porous Media

Science.gov (United States)

Yang, X.; Meng, X.; Tang, Y. H.; Guo, Z.; Karniadakis, G. E.

2017-12-01

Using emerging understanding of biological and environmental processes at fundamental scales to advance predictions of the larger system behavior requires the development of multiscale approaches, and there is strong interest in coupling models at different scales together in a hybrid multiscale simulation framework. A limited number of hybrid multiscale simulation methods have been developed for subsurface applications, mostly using application-specific approaches for model coupling. The proposed generalized hybrid multiscale approach is designed with minimal intrusiveness to the at-scale simulators (pre-selected) and provides a set of lightweight C++ scripts to manage a complex multiscale workflow utilizing a concurrent coupling approach. The workflow includes at-scale simulators (using the lattice-Boltzmann method, LBM, at the pore and Darcy scale, respectively), scripts for boundary treatment (coupling and kriging), and a multiscale universal interface (MUI) for data exchange. The current study aims to apply the generalized hybrid multiscale modeling approach to couple pore- and Darcy-scale models for flow and mixing-controlled reaction with precipitation/dissolution in heterogeneous porous media. The model domain is packed heterogeneously that the mixing front geometry is more complex and not known a priori. To address those challenges, the generalized hybrid multiscale modeling approach is further developed to 1) adaptively define the locations of pore-scale subdomains, 2) provide a suite of physical boundary coupling schemes and 3) consider the dynamic change of the pore structures due to mineral precipitation/dissolution. The results are validated and evaluated by comparing with single-scale simulations in terms of velocities, reactive concentrations and computing cost.

Enhanced four-wave mixing in graphene-silicon slow-light photonic crystal waveguides

International Nuclear Information System (INIS)

Zhou, Hao; Gu, Tingyi; McMillan, James F.; Wong, Chee Wei; Petrone, Nicholas; Zande, Arend van der; Hone, James C.; Yu, Mingbin; Lo, Guoqiang; Kwong, Dim-Lee; Feng, Guoying; Zhou, Shouhuan

2014-01-01

We demonstrate the enhanced four-wave mixing of monolayer graphene on slow-light silicon photonic crystal waveguides. 200-μm interaction length, a four-wave mixing conversion efficiency of −23 dB is achieved in the graphene-silicon slow-light hybrid, with an enhanced 3-dB conversion bandwidth of about 17 nm. Our measurements match well with nonlinear coupled-mode theory simulations based on the measured waveguide dispersion, and provide an effective way for all-optical signal processing in chip-scale integrated optics.

Hybrid mimics and hybrid vigor in Arabidopsis

Science.gov (United States)

Wang, Li; Greaves, Ian K.; Groszmann, Michael; Wu, Li Min; Dennis, Elizabeth S.; Peacock, W. James

2015-01-01

F1 hybrids can outperform their parents in yield and vegetative biomass, features of hybrid vigor that form the basis of the hybrid seed industry. The yield advantage of the F1 is lost in the F2 and subsequent generations. In Arabidopsis, from F2 plants that have a F1-like phenotype, we have by recurrent selection produced pure breeding F5/F6 lines, hybrid mimics, in which the characteristics of the F1 hybrid are stabilized. These hybrid mimic lines, like the F1 hybrid, have larger leaves than the parent plant, and the leaves have increased photosynthetic cell numbers, and in some lines, increased size of cells, suggesting an increased supply of photosynthate. A comparison of the differentially expressed genes in the F1 hybrid with those of eight hybrid mimic lines identified metabolic pathways altered in both; these pathways include down-regulation of defense response pathways and altered abiotic response pathways. F6 hybrid mimic lines are mostly homozygous at each locus in the genome and yet retain the large F1-like phenotype. Many alleles in the F6 plants, when they are homozygous, have expression levels different to the level in the parent. We consider this altered expression to be a consequence of transregulation of genes from one parent by genes from the other parent. Transregulation could also arise from epigenetic modifications in the F1. The pure breeding hybrid mimics have been valuable in probing the mechanisms of hybrid vigor and may also prove to be useful hybrid vigor equivalents in agriculture. PMID:26283378

Boron nitride-MWCNT/epoxy hybrid nanocomposites: Preparation and mechanical properties

International Nuclear Information System (INIS)

Ulus, Hasan; Üstün, Tugay; Eskizeybek, Volkan; Şahin, Ömer Sinan; Avcı, Ahmet; Ekrem, Mürsel

2014-01-01

Highlights: • We studied the effects of BN nanoplatelets on tensile strength and elasticity modulus for polymer composites. • We investigated the synergetic effects of BN nanoplatelets and MWCNTs on tensile strength and elasticity modulus for polymer composites. • Fracture surfaces were examined by SEM analysis. - Abstract: In this study, production and mechanical properties of hybrid nanocomposites have been investigated. Hybrid nanocomposites are consisting of boron nitride nanoplatelets (BN) and multiwall carbon nanotubes (MWCNT) embedded in epoxy resin. The BN and MWCNT were mixed to epoxy resin in different weight fractions and mixtures were utilized for tensile test specimen production. The synthesized BN and produced hybrid nanocomposites were characterized by SEM, TEM, XRD, FT-IR and TGA analyses. The elasticity modulus and tensile strength values were obtained via tensile tests. The fracture morphologies were investigated after tensile test by means of scanning electron microscopy

Testing a Cloud Provider Network for Hybrid P2P and Cloud Streaming Architectures

OpenAIRE

Cerviño Arriba, Javier; Rodríguez, Pedro; Trajkovska, Irena; Mozo Velasco, Alberto; Salvachúa Rodríguez, Joaquín

2011-01-01

The number of online real-time streaming services deployed over network topologies like P2P or centralized ones has remarkably increased in the recent years. This has revealed the lack of networks that are well prepared to respond to this kind of traffic. A hybrid distribution network can be an efficient solution for real-time streaming services. This paper contains the experimental results of streaming distribution in a hybrid architecture that consist of mixed connections among P2P and Clou...

An efficient method for hybrid density functional calculation with spin-orbit coupling

Science.gov (United States)

Wang, Maoyuan; Liu, Gui-Bin; Guo, Hong; Yao, Yugui

2018-03-01

In first-principles calculations, hybrid functional is often used to improve accuracy from local exchange correlation functionals. A drawback is that evaluating the hybrid functional needs significantly more computing effort. When spin-orbit coupling (SOC) is taken into account, the non-collinear spin structure increases computing effort by at least eight times. As a result, hybrid functional calculations with SOC are intractable in most cases. In this paper, we present an approximate solution to this problem by developing an efficient method based on a mixed linear combination of atomic orbital (LCAO) scheme. We demonstrate the power of this method using several examples and we show that the results compare very well with those of direct hybrid functional calculations with SOC, yet the method only requires a computing effort similar to that without SOC. The presented technique provides a good balance between computing efficiency and accuracy, and it can be extended to magnetic materials.

Hybrids - Best of both worlds. [liquid and solid propellants mated for safe reliable and low cost launch vehicles

Science.gov (United States)

Goldberg, Ben E.; Wiley, Dan R.

1991-01-01

An overview is presented of hybrid rocket propulsion systems whereby combining solids and liquids for launch vehicles could produce a safe, reliable, and low-cost product. The primary subsystems of a hybrid system consist of the oxidizer tank and feed system, an injector system, a solid fuel grain enclosed in a pressure vessel case, a mixing chamber, and a nozzle. The hybrid rocket has an inert grain, which reduces costs of development, transportation, manufacturing, and launch by avoiding many safety measures that must be taken when operating with solids. Other than their use in launch vehicles, hybrids are excellent for simulating the exhaust of solid rocket motors for material development.

In Situ Production of Graphene-Fiber Hybrid Structures

DEFF Research Database (Denmark)

Akia, Mandana; Cremar, Lee; Chipara, Mircea

2017-01-01

We report a scalable method to obtain a new material where large graphene sheets form webs linking carbon fibers. Film-fiber hybrid nonwoven mats are formed during fiber processing and converted to carbon structures after a simple thermal treatment. This contrasts with multistep methods...... that attempt to mix previously prepared graphene and fibers, or require complicated and costly processes for deposition of graphene over carbon fibers. The developed graphene-fiber hybrid structures have seamless connections between graphene and fibers, and in fact the graphene "veils" extend directly from one...... a capillarity effect that promoted the formation of thin veils, which become graphene sheets upon dehydration by sulfuric acid vapor followed by carbonization (at relatively low temperatures, below 800 °C). These veils extend over several micrometers within the pores of the fiber network, and consist...

Influence of Hybridizing Flax and Hemp-Agave Fibers with Glass Fiber as Reinforcement in a Polyurethane Composite

Directory of Open Access Journals (Sweden)

Pankaj Pandey

2016-05-01

Full Text Available In this study, six combinations of flax, hemp, and glass fiber were investigated for a hybrid reinforcement system in a polyurethane (PU composite. The natural fibers were combined with glass fibers in a PU composite in order to achieve a better mechanical reinforcement in the composite material. The effect of fiber hybridization in PU composites was evaluated through physical and mechanical properties such as water absorption (WA, specific gravity (SG, coefficient of linear thermal expansion (CLTE, flexural and compression properties, and hardness. The mechanical properties of hybridized samples showed mixed trends compared to the unhybridized samples, but hybridization with glass fiber reduced water absorption by 37% and 43% for flax and hemp-agave PU composites respectively.

Development of Cholinesterase Inhibitors Using (a)-Lipoic Acid-benzyl Piperazine Hybrid Molecules

International Nuclear Information System (INIS)

Kim, Beomcheol; Lee, Seunghwan; Jang, Mi; Shon, Min Young; Park, Jeong Ho

2013-01-01

A series of hybrid molecules between (α)-lipoic acid (ALA) and benzyl piperazines were synthesized and their in vitro cholinesterase [acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE)] inhibitory activities were evaluated. Even though the parent compounds did not show any inhibitory activity against cholinesterase (ChE), all hybrid molecules showed BuChE inhibitory activity. Some hybrid compounds also displayed AChE inhibitory activity. Specifically, ALA-1-(3-methylbenzyl)piperazine (15) was shown to be an effective inhibitor of both BuChE (IC 50 = 2.3 ± 0.7 μM) and AChE (IC 50 = 30.31 ± 0.64 μM). An inhibition kinetic study using compound 15 indicated a mixed inhibition type. Its binding affinity (K i ) value to BuChE is 2.91 ± 0.15 μM

Mixed-order phase transition in a minimal, diffusion-based spin model.

Science.gov (United States)

Fronczak, Agata; Fronczak, Piotr

2016-07-01

In this paper we exactly solve, within the grand canonical ensemble, a minimal spin model with the hybrid phase transition. We call the model diffusion based because its Hamiltonian can be recovered from a simple dynamic procedure, which can be seen as an equilibrium statistical mechanics representation of a biased random walk. We outline the derivation of the phase diagram of the model, in which the triple point has the hallmarks of the hybrid transition: discontinuity in the average magnetization and algebraically diverging susceptibilities. At this point, two second-order transition curves meet in equilibrium with the first-order curve, resulting in a prototypical mixed-order behavior.

A hybrid approach for biobjective optimization

DEFF Research Database (Denmark)

Stidsen, Thomas Jacob Riis; Andersen, Kim Allan

2018-01-01

to singleobjective problems is that no standard multiobjective solvers exist and specialized algorithms need to be programmed from scratch.In this article we will present a hybrid approach, which operates both in decision space and in objective space. The approach enables massive efficient parallelization and can...... be used to a wide variety of biobjective Mixed Integer Programming models. We test the approach on the biobjective extension of the classic traveling salesman problem, on the standard datasets, and determine the full set of nondominated points. This has only been done once before (Florios and Mavrotas...

Understanding usage of a hybrid website and smartphone app for weight management: a mixed-methods study.

Science.gov (United States)

Morrison, Leanne G; Hargood, Charlie; Lin, Sharon Xiaowen; Dennison, Laura; Joseph, Judith; Hughes, Stephanie; Michaelides, Danius T; Johnston, Derek; Johnston, Marie; Michie, Susan; Little, Paul; Smith, Peter Wf; Weal, Mark J; Yardley, Lucy

2014-10-22

Advancements in mobile phone technology offer huge potential for enhancing the timely delivery of health behavior change interventions. The development of smartphone-based health interventions (apps) is a rapidly growing field of research, yet there have been few longitudinal examinations of how people experience and use these apps within their day-to-day routines, particularly within the context of a hybrid Web- and app-based intervention. This study used an in-depth mixed-methods design to examine individual variation in (1) impact on self-reported goal engagement (ie, motivation, self-efficacy, awareness, effort, achievement) of access to a weight management app (POWeR Tracker) when provided alongside a Web-based weight management intervention (POWeR) and (2) usage and views of POWeR Tracker. Thirteen adults were provided access to POWeR and were monitored over a 4-week period. Access to POWeR Tracker was provided in 2 alternate weeks (ie, weeks 1 and 3 or weeks 2 and 4). Participants' goal engagement was measured daily via self-report. Mixed effects models were used to examine change in goal engagement between the weeks when POWeR Tracker was and was not available and whether the extent of change in goal engagement varied between individual participants. Usage of POWeR and POWeR Tracker was automatically recorded for each participant. Telephone interviews were conducted and analyzed using inductive thematic analysis to further explore participants' experiences using POWeR and POWeR Tracker. Access to POWeR Tracker was associated with a significant increase in participants' awareness of their eating (β1=0.31, P=.04) and physical activity goals (β1=0.28, P=.03). The level of increase varied between individual participants. Usage data showed that participants used the POWeR website for similar amounts of time during the weeks when POWeR Tracker was (mean 29 minutes, SD 31 minutes) and was not available (mean 27 minutes, SD 33 minutes). POWeR Tracker was mostly

Samoa's Education Policy: Negotiating a Hybrid Space for Values

Science.gov (United States)

Tuia, Tagataese Tupu; Iyer, Radha

2015-01-01

This paper analyses the education policy of Samoa to examine the values that are presented within as relevant to the education system. Drawing on the theory of postcolonialism and globalization, we illustrate how the global and local interact within the education policy to create a hybrid, heterogeneous mix of values and, while the policy…

Anaerobic digestion and gasification hybrid system for potential energy recovery from yard waste and woody biomass

International Nuclear Information System (INIS)

Yao, Zhiyi; Li, Wangliang; Kan, Xiang; Dai, Yanjun; Tong, Yen Wah; Wang, Chi-Hwa

2017-01-01

There is a rapid growing interest in using biomass as an alternative source for clean and sustainable energy production. In this work, a hybrid system was developed to combine anaerobic digestion (AD) and gasification for energy recovery from yard waste and woody biomass. The feasibility of the proposed hybrid system was validated experimentally and numerically and the energy efficiency was maximized by varying energy input in the drying process. The experiments were performed in two stages. At the first stage, AD of yard waste was conducted by mixing with anaerobic sludge. At the second stage, co-gasification was added as post-treatment for the AD residue for syngas production. The co-gasification experiments of AD residue and woody biomass were conducted at varying mixing ratios and varying moisture contents of AD residue. Optimal energy efficiency was found to be 70.8% at mixing ratio of 20 wt% AD residue with 30 wt% moisture content. Two kinetic models were then adapted for prediction of biogas produced in AD process and syngas produced in gasification process, respectively. Both experimental and numerical results showed that full utilization of biomass could be realized to produce energy through the combination of these two technologies. - Highlights: • The feasibility of the proposed two-stage hybrid system was validated experimentally and numerically. • The proposed hybrid system could effectively improve the quality of produced gas. • The operating parameters were optimized to improve the overall energy efficiency of the system. • Drying process was found to play an important role in determining overall energy efficiency. • Optimal moisture content of AD residue was investigated for maximizing energy efficiency.

Rapid hybridization of nucleic acids using isotachophoresis

Science.gov (United States)

Bercovici, Moran; Han, Crystal M.; Liao, Joseph C.; Santiago, Juan G.

2012-01-01

We use isotachophoresis (ITP) to control and increase the rate of nucleic acid hybridization reactions in free solution. We present a new physical model, validation experiments, and demonstrations of this assay. We studied the coupled physicochemical processes of preconcentration, mixing, and chemical reaction kinetics under ITP. Our experimentally validated model enables a closed form solution for ITP-aided reaction kinetics, and reveals a new characteristic time scale which correctly predicts order 10,000-fold speed-up of chemical reaction rate for order 100 pM reactants, and greater enhancement at lower concentrations. At 500 pM concentration, we measured a reaction time which is 14,000-fold lower than that predicted for standard second-order hybridization. The model and method are generally applicable to acceleration of reactions involving nucleic acids, and may be applicable to a wide range of reactions involving ionic reactants. PMID:22733732

Short-Term Planning of Hybrid Power System

Science.gov (United States)

Knežević, Goran; Baus, Zoran; Nikolovski, Srete

2016-07-01

In this paper short-term planning algorithm for hybrid power system consist of different types of cascade hydropower plants (run-of-the river, pumped storage, conventional), thermal power plants (coal-fired power plants, combined cycle gas-fired power plants) and wind farms is presented. The optimization process provides a joint bid of the hybrid system, and thus making the operation schedule of hydro and thermal power plants, the operation condition of pumped-storage hydropower plants with the aim of maximizing profits on day ahead market, according to expected hourly electricity prices, the expected local water inflow in certain hydropower plants, and the expected production of electrical energy from the wind farm, taking into account previously contracted bilateral agreement for electricity generation. Optimization process is formulated as hourly-discretized mixed integer linear optimization problem. Optimization model is applied on the case study in order to show general features of the developed model.

Air-water flooding in multirod channels: effects of spacer grids and blockages

International Nuclear Information System (INIS)

Cha, Jong Hee; Jun, Hyung Gil

1993-01-01

This paper presents the experimental results on flooding of countercurrent flow in vertical multirod channels, which consists of falling water film and upward air flow. In particular, the effects of spacer grids, with and without mixing vane, and of blockage in the multirod bundle on the behaviour of flooding were investigated. The 5 x 5 zircaloy tube bundle was used for the test section. The comparison of previous analytical models and empirical correlations with present data on flooding showed that the existing models and correlations predict much higher flooding curves. The spacer grid causes the lower flooding air flow rate to compare with the bare rod bundle. However, the mixing spacer grids need a higher flooding air flow rate for a constant liquid flow rate than the spacer grids without mixing vanes. The bundle containing blockages has the highest flooding air flow rate among the bundles with spacer grids and blokages. Empirical flooding correlations for the three types of test section have been made. (Author)

Interconversion between Free Charges and Bound Excitons in 2D Hybrid Lead Halide Perovskites

NARCIS (Netherlands)

Gelvez Rueda, M.C.; Hutter, E.M.; Cao, Duyen H.; Renaud, N.; Stoumpos, Constantinos C.; Hupp, Joseph T.; Savenije, T.J.; Kanatzidis, Mercouri G.; Grozema, F.C.

2017-01-01

The optoelectronic properties of hybrid perovskites can be easily tailored by varying their components. Specifically, mixing the common short organic cation (methylammonium (MA)) with a larger one (e.g., butyl ammonium (BA)) results in 2-dimensional perovskites with varying thicknesses of

Hybrid epidemic spreading - from Internet worms to HIV infection

OpenAIRE

Zhang, C.

2015-01-01

Epidemic phenomena are ubiquitous, ranging from infectious diseases, computer viruses, to information dissemination. Epidemics have traditionally been studied as a single spreading process, either in a fully mixed population or on a network. Many epidemics, however, are hybrid, employing more than one spreading mechanism. For example, the Internet worm Conficker spreads locally targeting neighbouring computers in local networks as well as globally by randomly probing any computer on the Inter...

The Effect of Clay/Multiwall Carbon Nanotube Hybrid Fillers on the Properties of Elastomer Nanocomposites

Directory of Open Access Journals (Sweden)

Sung Ho Song

2018-01-01

Full Text Available The hybrid fillers of 1D multiwalled carbon nanotubes (MWNT and 2D montmorillonite (MMT have led to excellent physical and chemical properties in high performance elastomer nanocomposites. In this study, the hybridization of PDDA (polydiallyldimethylammonium chloride functionalized MWNT (P-MWNT and hydroxyl-functionalized MMT (H-MMT was prepared by the electrostatic interaction between the positive charge on the MWNT and the negative charge on the MMT using a simple solution mixing process. Also, a styrene-butadiene rubber (SBR nanocomposite containing the hybrid nanofillers was prepared to improve the dispersion of nanofillers with SBR latex. The SBR nanocomposites with the hybrid nanofillers exhibited outstanding mechanical properties including modulus, tensile strength, and elongation at break, due to the enhanced interfacial bonding with the elastomer matrix. Furthermore, the hybrid nanofillers in the SBR matrix showed superior thermal and electrical properties and gas barrier performance at low loadings. The synergistic effects of the SBR produced by the hybridized nanofillers will open up new opportunities for elastomer composites with high performance.

Island shape, size and interface dependency on electronic and magnetic properties of graphene hexagonal-boron nitride (h-BN) in-plane hybrids

Science.gov (United States)

Akman, Nurten; Özdoğan, Cem

2018-04-01

We systematically investigate the energetics of ion implantation, stability, electronic, and magnetic properties of graphene/hexagonal boron nitrate (h-BN) in-plane hybrids through first principle calculations. We consider hexagonal and triangular islands in supercells of graphene and h-BN layouts. In the case of triangular islands, both phases mix with each other by either solely Csbnd N or Csbnd B bonds. We also patterned triangles with predominating Csbnd N or Csbnd B bonds at their interfaces. The energetics of island implantation is discussed in detail. Formation energies point out that the island implantation could be even exothermic for all hybrids studied in this work. Effects of size and shape of the island, and dominating bonding sort at the island-layout interfaces on the stability, band gap, and magnetic properties of hybrids are studied particularly. The hybrids become more stable with increasing island size. Regardless of the layout, hybrids with hexagonal islands are all non-magnetic and semiconducting. One can thus open a band gap in the semimetallic graphene by mixing it with the h-BN phase. In general, hybrids containing graphene triangles show metallic property and exhibit considerable amount of magnetic moments for possible localized spin utilizations. Total magnetic moment of hybrids with both graphene and h-BN layouts increases with growing triangle island as well. The spin densities of magnetic hybrids are derived from interfaces of the islands and diminish towards their center. We suggest that the increase in stability and magnetic moment depend on the number of atoms at the interfaces rather than the island size.

Coca-colonization and hybridization of diets among the Tz'utujil Maya.

Science.gov (United States)

Nagata, Jason M; Barg, Frances K; Valeggia, Claudia R; Bream, Kent D W

2011-01-01

Biomedical health professionals express increasing concern that rising consumption of soft drinks and processed foods in Mayan and Latin American eating patterns may lead to detrimental nutritional and health consequences. Scholars debate whether the pervading presence of Coca-Cola and Pepsi in developing countries represents "Coca-Colonization," synonymous with cultural imperialism, or cultural hybridization. Using mixed qualitative and quantitative research methods, including participant observation and semi-structured interviews, this study explores the development of Coca-Colonization and cultural hybridization among the Tz'utujil Maya of Santiago Atitlán, Guatemala. By specifically examining biomedical perspectives, cycles of conquest, the political economy, religion, celebrations, and the physical environment through the lens of soft drinks, this study finds that Coca-Colonization and cultural hybridization are complementary rather than mutually exclusive processes that contribute to dietary transitions, economic development, and differential health beliefs related to soft drink consumption.

Mechatronic Design of a New Humanoid Robot with Hybrid Parallel Actuation

Directory of Open Access Journals (Sweden)

Vítor Santos

2012-10-01

Full Text Available Humanoid robotics is unquestionably a challenging and long-term field of research. Of the numerous and most urgent challenges to tackle, autonomous and efficient locomotion may possibly be the most underdeveloped at present in the research community. Therefore, to pursue studies in relation to autonomy with efficient locomotion, the authors have been developing a new teen-sized humanoid platform with hybrid characteristics. The hybrid nature is clear in the mixed actuation based on common electrical motors and passive actuators attached in parallel to the motors. This paper presents the mechatronic design of the humanoid platform, focusing mainly on the mechanical structure, the design and simulation of the hybrid joints, and the different subsystems implemented. Trying to keep the appropriate human proportions and main degrees of freedom, the developed platform utilizes a distributed control architecture and a rich set of sensing capabilities, both ripe for future development and research.

Rotor boundary layer development with inlet guide vane (IGV) wake impingement

Science.gov (United States)

Jia, Lichao; Zou, Tengda; Zhu, Yiding; Lee, Cunbiao

2018-04-01

This paper examines the transition process in a boundary layer on a rotor blade under the impingement of an inlet guide vane wake. The effects of wake strengths and the reduced frequency on the unsteady boundary layer development on a low-speed axial compressor were investigated using particle image velocimetry. The measurements were carried out at two reduced frequencies (fr = fIGVS0/U2i, fr = 1.35, and fr = 0.675) with the Reynolds number, based on the blade chord and the isentropic inlet velocity, being 97 500. At fr = 1.35, the flow separated at the trailing edge when the wake strength was weak. However, the separation was almost totally suppressed as the wake strength increased. For the stronger wake, both the wake's high turbulence and the negative jet behavior of the wake dominated the interaction between the unsteady wake and the separated boundary layer on the suction surface of the airfoil. The boundary layer displacement thickened first due to the negative jet effect. Then, as the disturbances developed underneath the wake, the boundary layer thickness reduced gradually. The high disturbance region convected downstream at a fraction of the free-stream velocity and spread in the streamwise direction. The separation on the suction surface was suppressed until the next wake's arrival. Because of the long recovery time at fr = 0.675, the boundary layer thickened gradually as the wake convected further downstream and finally separated due to the adverse pressure gradient. The different boundary layer states in turn affected the development of disturbances.

A study of the Roper resonance as a hybrid state from J/ψ decays

International Nuclear Information System (INIS)

Ping, R.G.; Chiang, H.C.; Zou, B.S.

2004-01-01

The structure of the Roper resonance as a hybrid baryon is investigated through studying the transitional amplitudes in J/ψ->p-bar N*, N-bar *N* decays. We begin with perturbative QCD to describe the dynamical process for the J/ψ->3q-bar +3q decay to the lowest order of αs, and by extending the modified quark creation model to the J/ψ energy region to describe the J/ψ->3q-bar +3q+g process. The nonperturbative effects are incorporated by a simple quark model of baryons to evaluate the angular distribution parameters and decay widths for the processes J/ψ->p-bar N*, N-bar *N*. From fitting the decay width of J/ψ->γpp-bar to the experimental data, we extract the quark-pair creation strength gI=15.40-bar GeV. Our numerical results for J/ψ->p-bar N*, N-bar *N* decays show that the branching ratios for these decays are quite different if the Roper resonance is assumed to be a common 3q state or a pure hybrid state. For testing its mixing properties, we present a scheme to construct the Roper wave function by mixing vertical bar qqqg> state with a normal vertical bar qqq,2s> state. Under this picture, the ratios of the decay widths to that of the J/ψ->pp-bar decay are re-evaluated versus the mixing parameter. A test of the hybrid nature of the Roper resonance in J/ψ decays is discussed

Hybrid Propulsion Demonstration Program 250K Hybrid Motor

Science.gov (United States)

Story, George; Zoladz, Tom; Arves, Joe; Kearney, Darren; Abel, Terry; Park, O.

2003-01-01

The Hybrid Propulsion Demonstration Program (HPDP) program was formed to mature hybrid propulsion technology to a readiness level sufficient to enable commercialization for various space launch applications. The goal of the HPDP was to develop and test a 250,000 pound vacuum thrust hybrid booster in order to demonstrate hybrid propulsion technology and enable manufacturing of large hybrid boosters for current and future space launch vehicles. The HPDP has successfully conducted four tests of the 250,000 pound thrust hybrid rocket motor at NASA's Stennis Space Center. This paper documents the test series.

Flexural behavior of the fibrous cementitious composites (FCC) containing hybrid fibres

Science.gov (United States)

Ramli, Mahyuddin; Ban, Cheah Chee; Samsudin, Muhamad Fadli

2018-02-01

In this study, the flexural behavior of the fibrous cementitious composites containing hybrid fibers was investigated. Waste materials or by product materials such as pulverized fuel ash (PFA) and ground granulated blast-furnace slag (GGBS) was used as supplementary cement replacement. In addition, barchip and kenaf fiber will be used as additional materials for enhance the flexural behavior of cementitious composites. A seven mix design of fibrous cementitious composites containing hybrid fiber mortar were fabricated with PFA-GGBS as cement replacement at 50% with hybridization of barchip and kenaf fiber between 0.5% and 2.0% by total volume weight. The FCC with hybrid fibers mortar will be fabricated by using 50 × 50 × 50 mm, 40 × 40 × 160 mm and 350 × 125 × 30 mm steel mold for assessment of mechanical performances and flexural behavior characteristics. The flexural behavior and mechanical performance of the PFA-GGBS with hybrid fiber mortar block was assessed in terms of load deflection response, stress-strain response, crack development, compressive and flexural strength after water curing for 28 days. Moreover, the specimen HBK 1 and HBK 2 was observed equivalent or better in mechanical performance and flexural behavior as compared to control mortar.

From object to subject: hybrid identities of indigenous women in science

Science.gov (United States)

McKinley, Elizabeth

2008-12-01

The use of hybridity today suggests a less coherent, unified and directed process than that found in the Enlightenment science's cultural imperialism, but regardless of this neither concept exists outside power and inequality. Hence, hybridity raises the question of the terms of the mixture and the conditions of mixing. Cultural hybridity produced by colonisation, under the watchful eye of science at the time, and the subsequent life in a modern world since does not obscure the power that was embedded in the moment of colonisation. Indigenous identities are constructed within and by cultural power. While we all live in a global society whose consequences no one can escape, we remain unequal participants and globalisation remains an uneven process. This article argues that power has become a constitutive element in our own hybrid identities in indigenous people's attempts to participate in science and science education. Using the indigenous peoples of Aotearoa New Zealand (called Māori) as a site of identity construction, I argue that the move from being the object of science to the subject of science, through science education in schools, brings with it traces of an earlier meaning of `hybridity' that constantly erupts into the lives of Māori women scientists.

Development of Cholinesterase Inhibitors Using (a)-Lipoic Acid-benzyl Piperazine Hybrid Molecules

Energy Technology Data Exchange (ETDEWEB)

Kim, Beomcheol; Lee, Seunghwan; Jang, Mi; Shon, Min Young; Park, Jeong Ho [Hanbat National Univ., Daejeon (Korea, Republic of)

2013-11-15

A series of hybrid molecules between (α)-lipoic acid (ALA) and benzyl piperazines were synthesized and their in vitro cholinesterase [acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE)] inhibitory activities were evaluated. Even though the parent compounds did not show any inhibitory activity against cholinesterase (ChE), all hybrid molecules showed BuChE inhibitory activity. Some hybrid compounds also displayed AChE inhibitory activity. Specifically, ALA-1-(3-methylbenzyl)piperazine (15) was shown to be an effective inhibitor of both BuChE (IC{sub 50} = 2.3 ± 0.7 μM) and AChE (IC{sub 50} = 30.31 ± 0.64 μM). An inhibition kinetic study using compound 15 indicated a mixed inhibition type. Its binding affinity (K{sub i}) value to BuChE is 2.91 ± 0.15 μM.

Synthesis and electrical characterization of low-temperature thermal-cured epoxy resin/functionalized silica hybrid-thin films for application as gate dielectrics

Energy Technology Data Exchange (ETDEWEB)

Na, Moonkyong, E-mail: nmk@keri.re.kr [HVDC Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of); System on Chip Chemical Process Research Center, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 790-784 (Korea, Republic of); Kang, Young Taec [Creative and Fundamental Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of); Department of Polymer Science and Engineering, Pusan National University, Busan, 609-735 (Korea, Republic of); Kim, Sang Cheol [HVDC Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of); Kim, Eun Dong [Creative and Fundamental Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of)

2013-07-31

Thermal-cured hybrid materials were synthesized from homogenous hybrid sols of epoxy resins and organoalkoxysilane-functionalized silica. The chemical structures of raw materials and obtained hybrid materials were characterized using Fourier transform infrared spectroscopy. The thermal resistance of the hybrids was enhanced by hybridization. The interaction between epoxy matrix and the silica particles, which caused hydrogen bonding and van der Waals force was strengthened by organoalkoxysilane. The degradation temperature of the hybrids was improved by approximately 30 °C over that of the parent epoxy material. The hybrid materials were formed into uniformly coated thin films of about 50 nm-thick using a spin coater. An optimum mixing ratio was used to form smooth-surfaced hybrid films. The electrical property of the hybrid film was characterized, and the leakage current was found to be well below 10{sup −6} A cm{sup −2}. - Highlights: • Preparation of thermal-curable hybrid materials using epoxy resin and silica. • The thermal stability was enhanced through hybridization. • The insulation property of hybrid film was investigated as gate dielectrics.

Plasma mass density, species mix and fluctuation diagnostics using fast Alfven wave

International Nuclear Information System (INIS)

Ikezi, H.; deGrassie, J.S.; Pinsker, R.I.; Snider, R.T.

1996-06-01

The authors propose to employ a fast Alfven wave interferometer and reflectometer as a tokamak diagnostic to measure the plasma mass density, D-T species mix profile, and density fluctuations. Utilize the property that the phase velocity of the fast wave propagating across the magnetic field is the Alfven speed with thermal correction, this fast wave interferometer on the DIII-D tokamak was successfully used to obtain the line integrated density. Since the position of the ion-ion hybrid cut-off in tokamaks is uniquely determined by the species mix ratio and the wave frequency, the reflectometer arrangement finds the species mix profile. The inversion method of reflectometry is discussed. The multiple chord interferometer also measures the mass density fluctuation profile

Plasma mass density, species mix and fluctuation diagnostics using fast Alfven wave

Energy Technology Data Exchange (ETDEWEB)

Ikezi, H.; deGrassie, J.S.; Pinsker, R.I.; Snider, R.T.

1996-06-01

The authors propose to employ a fast Alfven wave interferometer and reflectometer as a tokamak diagnostic to measure the plasma mass density, D-T species mix profile, and density fluctuations. Utilize the property that the phase velocity of the fast wave propagating across the magnetic field is the Alfven speed with thermal correction, this fast wave interferometer on the DIII-D tokamak was successfully used to obtain the line integrated density. Since the position of the ion-ion hybrid cut-off in tokamaks is uniquely determined by the species mix ratio and the wave frequency, the reflectometer arrangement finds the species mix profile. The inversion method of reflectometry is discussed. The multiple chord interferometer also measures the mass density fluctuation profile.

Electroosmotic Flow in Mixed Polymer Brush-Grafted Nanochannels

Directory of Open Access Journals (Sweden)

Qianqian Cao

2016-12-01

Full Text Available Mixed polymer brush-grafted nanochannels—where two distinct species of polymers are alternately grafted on the inner surface of nanochannels—are an interesting class of nanostructured hybrid materials. By using a coarse-grained molecular dynamics simulation method, we are able to simulate the electrokinetic transport dynamics of the fluid in such nanochannels as well as the conformational behaviors of the mixed polymer brush. We find that (1 the brush adopts vertically-layered and longitudinally-separated structures due to the coupling of electroosmotic flow (EOF and applied electric field; (2 the solvent quality affects the brush conformations and the transport properties of the EOF; (3 the EOF flux non-monotonically depends on the grafting density, although the EOF velocity in the central region of the channel monotonically depends on the grafting density.

Effects of Hot Streak and Phantom Cooling on Heat Transfer in a Cooled Turbine Stage Including Particulate Deposition

Energy Technology Data Exchange (ETDEWEB)

Bons, Jeffrey [The Ohio State Univ., Columbus, OH (United States); Ameri, Ali [The Ohio State Univ., Columbus, OH (United States)

2016-01-08

. The new deposition model was implemented into the CFD model as a wall boundary condition, with various particle sizes investigated in the simulation. Simulations utilizing a steady mixing plane formulation and an unsteady sliding mesh were conducted and the flow solution of each was validated against experimental data. Results from each of these simulations, including impact and capture distributions and efficiencies, were compared and potential reasons for differences discussed in detail. The inclusion of a large range of particle sizes allowed investigation of trends with particle size, such as increased radial migration and reduced sticking efficiency at the larger particle sizes. The unsteady simulation predicted lower sticking efficiencies on the rotor blades than the mixing plane simulation for the majority of particle sizes. This is postulated to be due to the preservation of the hot streak and cool vane wake through the vane-rotor interface (which are smeared out circumferentially in the mixing-plane simulation). The results reported here represent the successful implementation of a novel deposition model into validated vane-rotor flow solutions that include a non-uniform inlet temperature profile and simulated vane cooling.

A hybrid adaptive large neighborhood search algorithm applied to a lot-sizing problem

DEFF Research Database (Denmark)

Muller, Laurent Flindt; Spoorendonk, Simon

This paper presents a hybrid of a general heuristic framework that has been successfully applied to vehicle routing problems and a general purpose MIP solver. The framework uses local search and an adaptive procedure which choses between a set of large neighborhoods to be searched. A mixed integer...... of a solution and to investigate the feasibility of elements in such a neighborhood. The hybrid heuristic framework is applied to the multi-item capacitated lot sizing problem with dynamic lot sizes, where experiments have been conducted on a series of instances from the literature. On average the heuristic...

Continuous mixer, process and use in a pumping plant for a high viscosity fluid

Energy Technology Data Exchange (ETDEWEB)

Cholet, H.

1993-03-12

The invention concerns a novel continuous mixer comprising a rotary shaft carrying two or more vanes for mixing two or more fluids of different viscosities supplied at the inlet of the mixer body and for providing, at the mixer body outlet, a mixture of viscosity lower than that of the more or most viscous fluid. Preferentially, the vane profile is such that, without fluid circulation, rotation of the vanes produces a reaction force parallel to the rotational axis and in the same direction as the resulting flow or does not produce a reaction force of significant magnitude parallel to the rotational axis. The mixer shaft is connected to a pump shaft which is rotated by hydraulic motor driven by pressurized fluid injection. The mixer is used especially for facilitating viscous crude oil pumping from directional wells including horizontal or inclined portions.

CFD analysis of the flow in the near wake of a generic PWR mixing grid

International Nuclear Information System (INIS)

Bieder, Ulrich; Falk, François; Fauchet, Gauthier

2015-01-01

geometry of the mixing vanes are dominant in this region. Thus, the application of turbulence models should not be tested close to mixing grids

Hybrid type I-type II superconducting behavior in magnesium diboride

International Nuclear Information System (INIS)

Kunchur, M.N.; Saracila, G.; Arcos, D.A.; Cui, Y.; Pogrebnyakov, A.; Orgiani, P.; Xi, X.X.

2006-01-01

In traditional type-II superconductors, an applied magnetic field depresses the transition temperature and introduces magnetic flux vortices that cause resistive losses accompanied by a broadening of the transition. High-field high-pulsed-current measurements have revealed a new hybrid behavior in disordered magnesium diboride films: The superconductivity survives high magnetic fields by entering a mixed state with vortices (like a type II superconductor) but holds its vortices nearly motionless and avoids dissipation (like a type I superconductor). A study of this phenomenon in magnesium diboride films with varying degrees of scattering indicate that the hybrid type I-type II behavior arises from the two-band nature of the superconductivity and the different degrees of influence that disorder exerts on its different bands. (author)

Magnetic field effects in hybrid perovskite devices

Science.gov (United States)

Zhang, C.; Sun, D.; Sheng, C.-X.; Zhai, Y. X.; Mielczarek, K.; Zakhidov, A.; Vardeny, Z. V.

2015-05-01

Magnetic field effects have been a successful tool for studying carrier dynamics in organic semiconductors as the weak spin-orbit coupling in these materials gives rise to long spin relaxation times. As the spin-orbit coupling is strong in organic-inorganic hybrid perovskites, which are promising materials for photovoltaic and light-emitting applications, magnetic field effects are expected to be negligible in these optoelectronic devices. We measured significant magneto-photocurrent, magneto-electroluminescence and magneto-photoluminescence responses in hybrid perovskite devices and thin films, where the amplitude and shape are correlated to each other through the electron-hole lifetime, which depends on the perovskite film morphology. We attribute these responses to magnetic-field-induced spin-mixing of the photogenerated electron-hole pairs with different g-factors--the Δg model. We validate this model by measuring large Δg (~ 0.65) using field-induced circularly polarized photoluminescence, and electron-hole pair lifetime using picosecond pump-probe spectroscopy.

Mixed-Matrix Membranes for CO2 and H2 Gas Separations Using Metal-Organic Framework and Mesoporus Hybrid Silicas

International Nuclear Information System (INIS)

Musselman, Inga; Balkus, Kenneth Jr.; Ferraris, John

2009-01-01

In this work, we have investigated the separation performance of polymer-based mixed-matrix membranes containing metal-organic frameworks and mesoporous hybrid silicas. The MOF/Matrimid(reg s ign) and MOP-18/Matrimid(reg s ign) membranes exhibited improved dispersion and mechanical strength that allowed high additive loadings with reduced aggregation, as is the case of the 80 wt% MOP-18/Matrimid(reg s ign) and the 80% (w/w) Cu-MOF/Matrimid(reg s ign) membranes. Membranes with up to 60% (w/w) ZIF-8 content exhibited similar mechanical strength and improved dispersion. The H 2 /CO 2 separation properties of MOF/Matrimid(reg s ign) mixed-matrix membranes was improved by either keeping the selectivity constant and increasing the permeability (MOF-5, Cu-MOF) or by improving both selectivity and permeability (ZIF-8). In the case of MOF-5/Matrimid(reg s ign) mixed-matrix membranes, the H 2 /CO 2 selectivity was kept at 2.6 and the H 2 permeability increased from 24.4 to 53.8 Barrers. For the Cu-MOF/Matrimid(reg s ign) mixed-matrix membranes, the H 2 /CO 2 selectivity was kept at 2.05 and the H 2 permeability increased from 17.1 to 158 Barrers. These two materials introduced porosity and uniform paths that enhanced the gas transport in the membranes. When ZIF-8/Matrimid(reg s ign) mixed-matrix membranes were studied, the H 2 /CO 2 selectivity increased from 2.9 to 4.4 and the permeability of H 2 increased from 26.5 to 35.8 Barrers. The increased H 2 /CO 2 selectivity in ZIF-8/Matrimid(reg s ign) membranes was explained by the sieving effect introduced by the ZIF-8 crystals (pore window 0.34 nm) that restricted the transport of molecules larger than H 2 . Materials with microporous and/or mesoporous cavities like carbon aerogel composites with zeolite A and zeolite Y, and membranes containing mesoporous ZSM-5 showed sieving effects for small molecules (e.g. H 2 and CO 2 ), however, the membranes were most selective for CO 2 due to the strong interaction of the zeolites with

Benchmarking transaction and analytical processing systems the creation of a mixed workload benchmark and its application

CERN Document Server

Bog, Anja

2014-01-01

This book introduces a new benchmark for hybrid database systems, gauging the effect of adding OLAP to an OLTP workload and analyzing the impact of commonly used optimizations in historically separate OLTP and OLAP domains in mixed-workload scenarios.

A hybrid adaptive large neighborhood search heuristic for lot-sizing with setup times

DEFF Research Database (Denmark)

Muller, Laurent Flindt; Spoorendonk, Simon; Pisinger, David

2012-01-01

This paper presents a hybrid of a general heuristic framework and a general purpose mixed-integer programming (MIP) solver. The framework is based on local search and an adaptive procedure which chooses between a set of large neighborhoods to be searched. A mixed integer programming solver and its......, and the upper bounds found by the commercial MIP solver ILOG CPLEX using state-of-the-art MIP formulations. Furthermore, we improve the best known solutions on 60 out of 100 and improve the lower bound on all 100 instances from the literature...

A Hybrid Optimization Method for Reactive Power and Voltage Control Considering Power Loss Minimization

DEFF Research Database (Denmark)

Liu, Chengxi; Qin, Nan; Bak, Claus Leth

2015-01-01

This paper proposes a hybrid optimization method to optimally control the voltage and reactive power with minimum power loss in transmission grid. This approach is used for the Danish automatic voltage control (AVC) system which is typically a non-linear non-convex problem mixed with both...

Blot hybridization analysis of TCR genes of T cells for five people exposed in a radiation accident

International Nuclear Information System (INIS)

Min Rui; Liu Benti; Cheng Tianmin; Yang Rujun; Meng Xiangshun; Xiao Jinsong

1996-01-01

Human lymphocyte total DNA was prepared in agarose plug by mixing cells with low melting agarose, and two restriction endonucleases were used for digestion of the total DNA with human α and β TCR cDNA probes. The total digested DNA from five people who were whole body exposed to 2.0-2.5 Gy ionizing radiation in an accident 4.5 years ago was hybridized by Southern blot method. The results showed that no obvious difference in hybridization bands was found between controls and the five victims when hybridizations were fulfilled in the total DNA which was digested by Hind III restriction endonuclease with both α and β probes. However, when the total DNA was digested with restriction endonuclease EcoR I and was hybridized with TCR α probe, four of the five exposed people showed a different hybridizing band pattern compared with the controls. The results are also discussed

A Study of Performance Output of a Multivane Air Engine Applying Optimal Injection and Vane Angles

Directory of Open Access Journals (Sweden)

Bharat Raj Singh

2012-01-01

Full Text Available This paper presents a new concept of the air engine using compressed air as the potential power source for motorbikes, in place of an internal combustion engine. The motorbike is proposed to be equipped with an air engine, which transforms the energy of the compressed air into mechanical motion energy. A mathematical model is presented here, and performance evaluation is carried out on an air-powered novel air turbine engine. The maximum power output is obtained as 3.977 kW (5.50 HP at the different rotor to casing diameter ratios, optimal injection angle 60°, vane angle 45° for linear expansion (i.e., at minimum air consumption when the casing diameter is kept 100 mm, at injection pressure 6 bar (90 psi and speed of rotation 2500 rpm. A prototype air engine is built and tested in the laboratory. The experimental results are also seen much closer to the analytical values, and the performance efficiencies are recorded around 70% to 95% at the speed of rotation 2500–3000 rpm.

Active unsteady aerodynamic suppression of rotating stall in an incompressible flow centrifugal compressor with vaned diffuser

Science.gov (United States)

Lawless, Patrick B.; Fleeter, Sanford

1991-01-01

A mathematical model is developed to analyze the suppression of rotating stall in an incompressible flow centrifugal compressor with a vaned diffuser, thereby addressing the important need for centrifugal compressor rotating stall and surge control. In this model, the precursor to to instability is a weak rotating potential velocity perturbation in the inlet flow field that eventually develops into a finite disturbance. To suppress the growth of this potential disturbance, a rotating control vortical velocity disturbance is introduced into the impeller inlet flow. The effectiveness of this control is analyzed by matching the perturbation pressure in the compressor inlet and exit flow fields with a model for the unsteady behavior of the compressor. To demonstrate instability control, this model is then used to predict the control effectiveness for centrifugal compressor geometries based on a low speed research centrifugal compressor. These results indicate that reductions of 10 to 15 percent in the mean inlet flow coefficient at instability are possible with control waveforms of half the magnitude of the total disturbance at the inlet.

Experimental investigations of the post-CHF heat transfer of R-134a flow-boiling in an annulus with spacer grids

International Nuclear Information System (INIS)

Lee, Kwi Lim; Chang, Soon Heung

2009-01-01

An experimental study was performed in the post-CHF condition using R-134a to investigate the effect of spacer grids on post-CHF heat transfer in an annulus channel. The experiments were conducted under the outlet pressures of 1.1 - 2.0 MPa, the mass fluxes of 100 - 400 kg/m 2 s and the inlet temperatures of 25 - 51degC. About 300 data of post-CHF data were obtained in the annular geometry without spacer grids and compared with several post-CHF correlations. The results showed the large prediction uncertainty mainly caused by the cold wall effect, so the empirical correlation for an annulus geometry without spacer grids was developed with the present experimental results. The heat transfer coefficient was calculated based on the heater rod temperature and the saturated vapor property. The average and root-mean-square(RMS) errors of the predictions were 0.17 % and 3.4 %, respectively. The experiments related to the spacer grid effects were performed with an I-type spacer grid and split-swirl mixing vane (with blockage-area ratios of 4.0 and 5.8 %). The spacer grid and mixing vane test results showed the enhancing effect on the heat transfer at the downstream location of the spacers. The experimental results from the spilt-swirl-type grid tests were more effective than the I-type grid tests. This was attributed to enhance the turbulence and increase the heat transfer caused by the mixing vane. (author)

A mixed finite element domain decomposition method for nearly elastic wave equations in the frequency domain

Energy Technology Data Exchange (ETDEWEB)

Feng, Xiaobing [Univ. of Tennessee, Knoxville, TN (United States)

1996-12-31

A non-overlapping domain decomposition iterative method is proposed and analyzed for mixed finite element methods for a sequence of noncoercive elliptic systems with radiation boundary conditions. These differential systems describe the motion of a nearly elastic solid in the frequency domain. The convergence of the iterative procedure is demonstrated and the rate of convergence is derived for the case when the domain is decomposed into subdomains in which each subdomain consists of an individual element associated with the mixed finite elements. The hybridization of mixed finite element methods plays a important role in the construction of the discrete procedure.

Position Analysis of a Hybrid Serial-Parallel Manipulator in Immersion Lithography

Directory of Open Access Journals (Sweden)

Jie-jie Shao

2015-01-01

Full Text Available This paper proposes a novel hybrid serial-parallel mechanism with 6 degrees of freedom. The new mechanism combines two different parallel modules in a serial form. 3-P̲(PH parallel module is architecture of 3 degrees of freedom based on higher joints and specializes in describing two planes’ relative pose. 3-P̲SP parallel module is typical architecture which has been widely investigated in recent researches. In this paper, the direct-inverse position problems of the 3-P̲SP parallel module in the couple mixed-type mode are analyzed in detail, and the solutions are obtained in an analytical form. Furthermore, the solutions for the direct and inverse position problems of the novel hybrid serial-parallel mechanism are also derived and obtained in the analytical form. The proposed hybrid serial-parallel mechanism is applied to regulate the immersion hood’s pose in an immersion lithography system. Through measuring and regulating the pose of the immersion hood with respect to the wafer surface simultaneously, the immersion hood can track the wafer surface’s pose in real-time and the gap status is stabilized. This is another exploration to hybrid serial-parallel mechanism’s application.

[Acute hybrid leukemia. Review of the literature and presentation of a case].

Science.gov (United States)

Guzzini, F; Angelopoulos, N; Banfi, L; Coppetti, D; Ceppi, M; Camerone, G

1990-03-01

In the last years, the development of immunophenotypic and molecular analyses allowed to recognize several cases of hybrid acute leukemia (AL), whose blast cell display both lymphoid and myeloid features. Hybrid, or mixed-lineage, AL seems to have distinct clinical manifestations and hematological findings, and is mainly characterized by resistance to chemotherapy and poor prognosis. We report on a patient with AL, which showed a very rapid switch from the lymphoblastic phenotype exhibited at presentation to a myelomonoblastic one, appeared at first relapse, and lastly progressed to an undifferentiated leukemia in the terminal phase. Together with this morphologic and cytochemical evolution, leukemic cells expressed, besides the primary early-B antigens, new immunological markers related to T-lymphocytic and myeloid lineages. Based on this observation and current understanding of the ontogenesis of hematologic malignancies, we discuss biological mechanisms which are likely to underlie hybrid leukemia.

Genomic effects on advertisement call structure in diploid and triploid hybrid waterfrogs (Anura, Pelophylax esculentus).

Science.gov (United States)

Hoffmann, Alexandra; Reyer, Heinz-Ulrich

2013-12-04

In anurans, differences in male mating calls have intensively been studied with respect to taxonomic classification, phylogeographic comparisons among different populations and sexual selection. Although overall successful, there is often much unexplained variation in these studies. Potential causes for such variation include differences among genotypes and breeding systems, as well as differences between populations. We investigated how these three factors affect call properties in male water frogs of Pelophylax lessonae (genotype LL), P. ridibundus (RR) and their interspecific hybrid P. esculentus which comes in diploid (LR) and triploid types (LLR, LRR). We investigated five call parameters that all showed a genomic dosage effect, i.e. they either decreased or increased with the L/R ratio in the order LL-LLR-LR-LRR-RR. Not all parameters differentiated equally well between the five genotypes, but combined they provided a good separation. Two of the five call parameters were also affected by the breeding system. Calls of diploid LR males varied, depending on whether these males mated with one or both of the parental species (diploid systems) or triploid hybrids (mixed ploidy systems). With the exception of the northernmost mixed-ploidy population, call differences were not related to the geographic location of the population and they were not correlated with genetic distances in the R and L genomes. We found an influence of all three tested factors on call parameters, with the effect size decreasing from genotype through breeding system to geographic location of the population. Overall, results were in line with predictions from a dosage effect in L/R ratios, but in three call parameters all three hybrid types were more similar to one or the other parental species. Also calls of diploid hybrids varied between breeding systems in agreement with the sexual host required for successful reproduction. The lack of hybrid call differences in a mixed-ploidy population at

Study on MPI/OpenMP hybrid parallelism for Monte Carlo neutron transport code

International Nuclear Information System (INIS)

Liang Jingang; Xu Qi; Wang Kan; Liu Shiwen

2013-01-01

Parallel programming with mixed mode of messages-passing and shared-memory has several advantages when used in Monte Carlo neutron transport code, such as fitting hardware of distributed-shared clusters, economizing memory demand of Monte Carlo transport, improving parallel performance, and so on. MPI/OpenMP hybrid parallelism was implemented based on a one dimension Monte Carlo neutron transport code. Some critical factors affecting the parallel performance were analyzed and solutions were proposed for several problems such as contention access, lock contention and false sharing. After optimization the code was tested finally. It is shown that the hybrid parallel code can reach good performance just as pure MPI parallel program, while it saves a lot of memory usage at the same time. Therefore hybrid parallel is efficient for achieving large-scale parallel of Monte Carlo neutron transport. (authors)

Hybrid Spectral Unmixing: Using Artificial Neural Networks for Linear/Non-Linear Switching

Directory of Open Access Journals (Sweden)

Asmau M. Ahmed

2017-07-01

Full Text Available Spectral unmixing is a key process in identifying spectral signature of materials and quantifying their spatial distribution over an image. The linear model is expected to provide acceptable results when two assumptions are satisfied: (1 The mixing process should occur at macroscopic level and (2 Photons must interact with single material before reaching the sensor. However, these assumptions do not always hold and more complex nonlinear models are required. This study proposes a new hybrid method for switching between linear and nonlinear spectral unmixing of hyperspectral data based on artificial neural networks. The neural networks was trained with parameters within a window of the pixel under consideration. These parameters are computed to represent the diversity of the neighboring pixels and are based on the Spectral Angular Distance, Covariance and a non linearity parameter. The endmembers were extracted using Vertex Component Analysis while the abundances were estimated using the method identified by the neural networks (Vertex Component Analysis, Fully Constraint Least Square Method, Polynomial Post Nonlinear Mixing Model or Generalized Bilinear Model. Results show that the hybrid method performs better than each of the individual techniques with high overall accuracy, while the abundance estimation error is significantly lower than that obtained using the individual methods. Experiments on both synthetic dataset and real hyperspectral images demonstrated that the proposed hybrid switch method is efficient for solving spectral unmixing of hyperspectral images as compared to individual algorithms.

Development of 3-D Flow Analysis Code for Fuel Assembly using Unstructured Grid System

Energy Technology Data Exchange (ETDEWEB)

Myong, Hyon Kook; Kim, Jong Eun; Ahn, Jong Ki; Yang, Seung Yong [Kookmin Univ., Seoul (Korea, Republic of)

2007-03-15

The flow through a nuclear rod bundle with mixing vanes are very complex and required a suitable turbulence model to be predicted accurately. Final objective of this study is to develop a CFD code for fluid flow and heat transfer analysis in a nuclear fuel assembly using unstructured grid system. In order to develop a CFD code for fluid flow and heat transfer analysis in a nuclear fuel assembly using unstructured grid system, the following researches are made: - Development of numerical algorithm for CFD code's solver - Grid and geometric connectivity data - Development of software(PowerCFD code) for fluid flow and heat transfer analysis in a nuclear fuel assembly using unstructured grid system - Modulation of software(PowerCFD code) - Development of turbulence model - Development of analysis module of RANS/LES hybrid models - Analysis of turbulent flow and heat transfer - Basic study on LES analysis - Development of main frame on pre/post processors based on GUI - Algorithm for fully-developed flow.

Development of 3-D Flow Analysis Code for Fuel Assembly using Unstructured Grid System

International Nuclear Information System (INIS)

Myong, Hyon Kook; Kim, Jong Eun; Ahn, Jong Ki; Yang, Seung Yong

2007-03-01

The flow through a nuclear rod bundle with mixing vanes are very complex and required a suitable turbulence model to be predicted accurately. Final objective of this study is to develop a CFD code for fluid flow and heat transfer analysis in a nuclear fuel assembly using unstructured grid system. In order to develop a CFD code for fluid flow and heat transfer analysis in a nuclear fuel assembly using unstructured grid system, the following researches are made: - Development of numerical algorithm for CFD code's solver - Grid and geometric connectivity data - Development of software(PowerCFD code) for fluid flow and heat transfer analysis in a nuclear fuel assembly using unstructured grid system - Modulation of software(PowerCFD code) - Development of turbulence model - Development of analysis module of RANS/LES hybrid models - Analysis of turbulent flow and heat transfer - Basic study on LES analysis - Development of main frame on pre/post processors based on GUI - Algorithm for fully-developed flow

A hybrid approach to device integration on a genetic analysis platform

International Nuclear Information System (INIS)

Brennan, Des; Justice, John; Aherne, Margaret; Galvin, Paul; Jary, Dorothee; Kurg, Ants; Berik, Evgeny; Macek, Milan

2012-01-01

Point-of-care (POC) systems require significant component integration to implement biochemical protocols associated with molecular diagnostic assays. Hybrid platforms where discrete components are combined in a single platform are a suitable approach to integration, where combining multiple device fabrication steps on a single substrate is not possible due to incompatible or costly fabrication steps. We integrate three devices each with a specific system functionality: (i) a silicon electro-wetting-on-dielectric (EWOD) device to move and mix sample and reagent droplets in an oil phase, (ii) a polymer microfluidic chip containing channels and reservoirs and (iii) an aqueous phase glass microarray for fluorescence microarray hybridization detection. The EWOD device offers the possibility of fully integrating on-chip sample preparation using nanolitre sample and reagent volumes. A key challenge is sample transfer from the oil phase EWOD device to the aqueous phase microarray for hybridization detection. The EWOD device, waveguide performance and functionality are maintained during the integration process. An on-chip biochemical protocol for arrayed primer extension (APEX) was implemented for single nucleotide polymorphism (SNiP) analysis. The prepared sample is aspirated from the EWOD oil phase to the aqueous phase microarray for hybridization. A bench-top instrumentation system was also developed around the integrated platform to drive the EWOD electrodes, implement APEX sample heating and image the microarray after hybridization. (paper)

Analysis of hybrid energy systems for application in southern Ghana

International Nuclear Information System (INIS)

Adaramola, Muyiwa S.; Agelin-Chaab, Martin; Paul, Samuel S.

2014-01-01

Highlights: • The option of using hybrid energy for electricity in remote areas of Ghana is examined. • The cost of electricity produced by the hybrid system is found to be $0.281/kW h. • The levelized cost of electricity increase by 9% when the PV price is increased from $3000/kW to $7500/kW. - Abstract: Due to advances in renewable energy technologies and increase in oil price, hybrid renewable energy systems are becoming increasingly attractive for power generation applications in remote areas. This paper presents an economic analysis of the feasibility of utilizing a hybrid energy system consisting of solar, wind and diesel generators for application in remote areas of southern Ghana using levelized cost of electricity (LCOE) and net present cost of the system. The annual daily average solar global radiation at the selected site is 5.4 kW h/m 2 /day and the annual mean wind speed is 5.11 m/s. The National Renewable Energy Laboratory’s Hybrid Optimization Model for Electric Renewable (HOMER) software was employed to carry out the present study. Both wind data and the actual load data have been used in the simulation model. It was found that a PV array of 80 kW, a 100 kW wind turbine, two generators with combined capacity of 100 kW, a 60 kW converter/inverter and a 60 Surrette 4KS25P battery produced a mix of 791.1 MW h of electricity annually. The cost of electricity for this hybrid system is found to be $0.281/kW h. Sensitivity analysis on the effect of changes in wind speed, solar global radiation and diesel price on the optimal energy was investigated and the impact of solar PV price on the LCOE for a selected hybrid energy system was also presented

Performance Analysis for One-Step-Ahead Forecasting of Hybrid Solar and Wind Energy on Short Time Scales

Directory of Open Access Journals (Sweden)

Jing Huang

2018-05-01

Full Text Available With ever increasing demand for electricity and the huge potential of renewable energy, an increasing number of renewable-energy sources are being used to generate electricity. However, due to the intermittency of renewable-energy generation, many researchers try to overcome the variable nature of renewable energy. A hybrid renewable-energy system is one possible way to introduce smoothing of the supply. Many hybrid renewable-energy studies focus on system optimization and management. This paper mainly researches the performance prediction accuracy of a hybrid solar and wind system. Through a mixed autoregressive and dynamical system model, we test the predictability of the hybrid system and compare it with individual solar and wind series forecasting. After error analysis, the predictability of the hybrid system shows a better performance than solar or wind for Adelaide global solar radiation and Starfish Hill wind farm data. The prediction errors were reduced by 13% to more than 30% according to various error analyses. This result indicates an advantage of the hybrid solar and wind system compared to solar and wind systems taken individually.

Hybrid inorganic-organic adsorbents Part 1: Synthesis and characterization of mesoporous zirconium titanate frameworks containing coordinating organic functionalities.

Science.gov (United States)