WorldWideScience

Sample records for box-shaped floating structure

  1. On the hydroelastic response of box-shaped floating structure with shallow draft. Tank test with large scale model; Senkitsusui hakogata futai no harochu dansei oto ni tsuite. Ogata mokei ni yoru suiso shiken

    Energy Technology Data Exchange (ETDEWEB)

    Yago, K.; Endo, H. [Ship Research Inst., Tokyo (Japan)

    1996-12-31

    The hydroelastic response test was carried out in waves using an approximately 10m long large model, and the numerical analysis was done by the direct method, for a commercial-size (300m long) box-shaped floating structure with shallow draft. The scale ratio of the model is 1/30.8, and the minimum wave cycle is around 0.7s from wave-making capacity of the tank, which corresponds to 4 to 14s with the commercial-size structure. Elastic displacement and bending strain were measured. The calculated results by the direct method are in good agreement with the observed results. The fluid dynamic mutual interference effects between elements are weak in added mass but strong in damping force, indicating that the range of mutual interference is strongly related to rolling cycle in the range of mutual interference. Wave pressure on the floating structure bottom is high at the upper side of the wave, greatly damping towards the downside of the wave. However, response amplitude of elastic displacement tends to increase at the ends, both in upside and downside of the wave. For the floating structure studied, the 0 to 4th mode components are predominant in longitudinal waves, and the 6th or higher mode components are negligibly low. 21 refs., 15 figs., 2 tabs.

  2. Efficient method for predicting crystal structures at finite temperature: variable box shape simulations.

    Science.gov (United States)

    Filion, Laura; Marechal, Matthieu; van Oorschot, Bas; Pelt, Daniël; Smallenburg, Frank; Dijkstra, Marjolein

    2009-10-30

    We present an efficient and robust method based on Monte Carlo simulations for predicting crystal structures at finite temperature. We apply this method, which is surprisingly easy to implement, to a variety of systems, demonstrating its effectiveness for hard, attractive, and anisotropic interactions, binary mixtures, semi-long-range soft interactions, and truly long-range interactions where the truly long-range interactions are treated using Ewald sums. In the case of binary hard-sphere mixtures, star polymers, and binary Lennard-Jones mixtures, the crystal structures predicted by this algorithm are consistent with literature, providing confidence in the method. Finally, we predict new crystal structures for hard asymmetric dumbbell particles, bowl-like particles and hard oblate cylinders and present the phase diagram for the oblate cylinders based on full free energy calculations. PMID:19905838

  3. Box-shaped halophilic bacteria.

    OpenAIRE

    Javor, B; Requadt, C; Stoeckenius, W

    1982-01-01

    Three morphologically similar strains of halophilic, box-shaped procaryotes have been isolated from brines collected in the Sinai, Baja California (Mexico), and southern California (United States). Although the isolates in their morphology resemble Walsby's square bacteria, which are a dominant morphological type in the Red Sea and Baja California brines, they are probably not identical to them. The cells show the general characteristics of extreme halophiles and archaebacteria. They contain ...

  4. Large floating structures technological advances

    CERN Document Server

    Wang, BT

    2015-01-01

    This book surveys key projects that have seen the construction of large floating structures or have attained detailed conceptual designs. This compilation of key floating structures in a single volume captures the innovative features that mark the technological advances made in this field of engineering, and will provide a useful reference for ideas, analysis, design, and construction of these unique and emerging urban projects to offshore and marine engineers, urban planners, architects and students.

  5. Study on Floating Properties and Stability of Air Floated Structures

    Institute of Scientific and Technical Information of China (English)

    别社安; 及春宁; 任增金; 李增志

    2002-01-01

    In this paper, the buoyancy, kinetic properties and stability of air floated structures have been studied by theoreticaland experimental methods. The equations for calculation of the buoyancy of the air floated buoy are derived according tothe Boyler law and the equilibrium equations of the air floated structure are established. Through simplification of the airfloated structure as a single freedom rigid body and spring system, the natural period of heaving and some kinetic proper-ties are discussed. In the stability analysis, the formulas for calculation of the meta centric height are presented. The the-oretical results are in good agreement with the data observed from the model test and prototype test. The air buoyancy de-crease coefficient presented in this paper has a large influence on the floating state, stability and dynamic properties of theair floated structure. The stability of the air floated structure can also be judged by the parameter of meta centric height,and calculations show that the air floated structure is less stable than the conventional float.

  6. Nonlinear dynamic behaviors of a floating structure in focused waves

    Science.gov (United States)

    Cao, Fei-feng; Zhao, Xi-zeng

    2015-12-01

    Floating structures are commonly seen in coastal and offshore engineering. They are often subjected to extreme waves and, therefore, their nonlinear dynamic behaviors are of great concern. In this paper, an in-house CFD code is developed to investigate the accurate prediction of nonlinear dynamic behaviors of a two-dimensional (2-D) box-shaped floating structure in focused waves. Computations are performed by an enhanced Constrained Interpolation Profile (CIP)-based Cartesian grid model, in which a more accurate VOF (Volume of Fluid) method, the THINC/SW scheme (THINC: tangent of hyperbola for interface capturing; SW: Slope Weighting), is used for interface capturing. A focusing wave theory is used for the focused wave generation. The wave component of constant steepness is chosen. Comparisons between predictions and physical measurements show good agreement including body motions and free surface profiles. Although the overall agreement is good, some discrepancies are observed for impact pressure on the superstructure due to water on deck. The effect of grid resolution on the results is checked. With a fine grid, no obvious improvement is seen in the global body motions and impact pressures due to water on deck. It is concluded that highly nonlinear phenomena, such as distorted free surface, large-amplitude body motions, and violent impact flow, have been predicted successfully.

  7. 平板箱型天线阵面的封闭式风冷散热结构设计%Structure Design of Heat Dissipation with Enclosed Air Cooled Method for Flat Box-shaped Antenna Cabin

    Institute of Scientific and Technical Information of China (English)

    向熠; 王勇

    2014-01-01

    对雷达平板箱型天线阵面的散热设计进行了分析。阵面单元数量多,单元间距狭小,阵面冷却采用强迫循环封闭式空调风冷的方式进行。采用有限元方法对阵面流场进行了仿真分析,在此基础上对阵面散热结构进行了优化设计。结果表明,阵面结构的热设计符合系统散热要求。%The design of heat dissipation related to the flat box-shaped antenna cabin is discussed. Because of the large amount of antenna units and the small unit spacing, a recyclable forced air cooled method is applied. The finite element analysis is utilized to simulate the flow field and the temperature field, and base on the simulation the structure of the heat dissipation is optimized. The results show that the thermal design of the cabin agrees with the requirements of the system heat dissipation.

  8. Floating structures (based on water activities)

    OpenAIRE

    Rodionovskaya Inna Serafi movna; Kocheryaev Stanislav Alexandrovich; Shakhova Marina Evgenevna

    2012-01-01

    The article briefly describes the types of structures that are widely spread worldwide, and many well-known projects that remain unimplemented. Particular attention is driven to the main features of floating structures and areas of their application. Despite the advances of the present-day technology, floating structures are only used in the travel industry and low-rise construction. The authors consider a substantial though yet unexplored potential of rivers, seas and lakes, a...

  9. Dynamic Magnification Factor in a Box-Shape Steel Girder

    Science.gov (United States)

    Rahbar-Ranji, A.

    2014-01-01

    The dynamic effect of moving loads on structures is treated as a dynamic magnification factor when resonant is not imminent. Studies have shown that the calculated magnification factors from field measurements could be higher than the values specified in design codes. It is the main aim of present paper to investigate the applicability and accuracy of a rule-based expression for calculation of dynamic magnification factor for lifting appliances used in marine industry. A steel box shape girder of a crane is considered and transient dynamic analysis using computer code ANSYS is implemented. Dynamic magnification factor is calculated for different loading conditions and compared with rule-based equation. The effects of lifting speeds, acceleration, damping ratio and position of cargo are examined. It is found that rule-based expression underestimate dynamic magnification factor.

  10. Some Aspects of Arctic Offshore Floating Structures

    OpenAIRE

    Lubbad, Raed Khalil

    2011-01-01

    The present work highlights some aspects related to the analyses of Arctic offshore floating structures. This thesis consists of five papers, which can be divided into two main categories. One category deals with the dynamics of slender structures with an emphasis on the prediction and suppression of vortex induced vibrations (VIV), and the other category examines the process of interaction between sloping structures and sea ice with focus on developing a numerical model to simulate this proc...

  11. Influence of Floating Monitoring Platform Structure on the Hydrostatic Characteristics

    Directory of Open Access Journals (Sweden)

    Su Feng

    2015-01-01

    Full Text Available According to the environment and work styles, the underwater monitoring devices can be divided into three type, fixed monitoring device, the floating monitoring device and mobile monitoring device. Floating monitoring platform is a new type of monitoring device of the floating monitoring device, which is mainly used for underwater video monitoring of pool. as the floating platform monitoring in water motion and hydrostatic characteristics are closely related, the influent of counterweight, weight distance and floating body diameter of the structure parameters on its hydrostatic characteristics and the natural periods for roll, pitch and heave should be considered, In this work, the floating body diameter influent most, the counterweight followed, and the structure parameters have different influence on the natural periods for roll, pitch and heave , it need to be analyzed according to the concrete structure parameters.

  12. On the estimation method of hydrodynamic forces acting on a huge floating structure; Choogata futai ni hataraku haryoku ryutairyoku no suiteiho ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Kagemoto, H.; Fujino, M.; Zhu, T. [The University of Tokyo, Tokyo (Japan)

    1996-12-31

    A floating structure such as an international airport is anticipated to have a length of about 5,000 m and a width of about 1,000 m. A singular point method may be used as a method to estimate force that such a floating body is subjected to from waves. In order to derive a solution with practically sufficient accuracy, 1250 elements are required in the length direction and 250 elements in the width direction, or a total of 312,500 elements. Calculating this number of elements should use finally a linear equation system handling complex coefficients comprising 312,500 elements, which would require a huge amount of calculation time. This paper proposes a method to derive solution on wave forces acting on a super-large floating structure or fluid force coefficients such as added mass coefficients and decay coefficients at a practically workable calculation amount and still without degrading the accuracy. The structure was assumed to be a box-shaped structure. Strengths of the singular points to be distributed on each element were assumed to be almost constant except for edges in lateral, oblique and longitudinal waves. Under this assumption, the interior of the floating structure excepting its edges was represented by several large elements to have reduced the number of elements. A calculation method proposed based on this conception was verified of its effectiveness. 2 refs., 25 figs., 3 tabs.

  13. On Hydroelastic Body-Boundary Condition of Floating Structures

    DEFF Research Database (Denmark)

    Xia, Jinzhu

    1996-01-01

    A general linear body boundary condition of hydroelastic analysis of arbitrary shaped floating structures generalizes the classic kinematic rigid-body (Timman-Newman) boundary condition for seakeeping problems. The new boundary condition is consistent with the existing theories under certain assu...

  14. The effect of box shape on the dynamic properties of proteins simulated under periodic boundary conditions

    NARCIS (Netherlands)

    Wassenaar, T.A.; Mark, A.E.

    2006-01-01

    The effect of the box shape on the dynamic behavior of proteins simulated under periodic boundary conditions is evaluated. In particular, the influence of simulation boxes defined by the near-densest lattice packing (NDLP) in conjunction with rotational constraints is compared to that of standard bo

  15. Reliability-Based Optimal Design for Very Large Floating Structure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shu-hua(张淑华); FUJIKUBO Masahiko

    2003-01-01

    Costs and losses induced by possible future extreme environmental conditions and difficulties in repairing post-yielding damage strongly suggest the need for proper consideration in design rather than just life loss prevention. This can be addressed through the development of design methodology that balances the initial cost of the very large floating structure (VLFS) against the expected potential losses resulting from future extreme wave-induced structural damage. Here, the development of a methodology for determining optimal, cost-effective design will be presented and applied to a VLFS located in the Tokyo bay. Optimal design criteria are determined based on the total expected life-cycle cost and acceptable damage probability and curvature of the structure, and a set of sizes of the structure are obtained. The methodology and applications require expressions of the initial cost and the expected life-cycle damage cost as functions of the optimal design variables. This study includes the methodology, total life-cycle cost function, structural damage modeling, and reliability analysis.

  16. A comparison on the dynamics of a floating vertical axis wind turbine on three different floating support structures

    OpenAIRE

    Collu, Maurizio; Borg, Michael

    2014-01-01

    To increase the competitiveness of offshore wind energy in the global energy market, it is necessary to identify optimal offshore wind turbine configurations to deliver the lowest cost of energy. For deep waters where floating wind turbines are the feasible support structure option, the vertical axis wind turbine concept might prove to be one of these optimal configurations. This paper carries out a preliminary investigation into the dynamics of a vertical axis wind turbine coupled with three...

  17. Floating wind generators offshore wind farm: Implications for structural loads and control actions

    International Nuclear Information System (INIS)

    This paper describes the work currently carried out in the design of floating wind generators and their involvement in the future development of power generation in marine farms in depths exceeding 20 m. We discuss the main issues to be taken into account in the design of floating platforms, including the involvement of structural loads they bear. Also from a standpoint of control engineering are discussed strategies to reduce structural loads such a system to ensure adequate durability and therefore ensuring their economic viability. Finally, the abstract modeling tools for floating wind turbines that can be used in both structural design and the design of appropriate control algorithms

  18. An Integrated Structural Strength Analysis Method for Spar Type Floating Wind Turbine

    Institute of Scientific and Technical Information of China (English)

    胡志强; 刘毅; 王晋

    2016-01-01

    An integrated structural strength analysis method for a Spar type floating wind turbine is proposed in this paper, and technical issues related to turbine structure modeling and stress combination are also addressed. The NREL-5MW “Hywind” Spar type wind turbine is adopted as study object. Time-domain dynamic coupled simulations are performed by a fully-coupled aero-hydro-servo-elastic tool, FAST, on the purpose of obtaining the dynamic characteristics of the floating wind turbine, and determining parameters for design load cases of finite element calculation. Then design load cases are identified, and finite element analyses are performed for these design load cases. The structural stresses due to wave-induced loads and wind-induced loads are calculated, and then combined to assess the structural strength of the floating wind turbine. The feasibility of the proposed structural strength analysis method for floating wind turbines is then validated.

  19. An integrated structural strength analysis method for Spar type floating wind turbine

    Science.gov (United States)

    Hu, Zhi-qiang; Liu, Yi; Wang, Jin

    2016-04-01

    An integrated structural strength analysis method for a Spar type floating wind turbine is proposed in this paper, and technical issues related to turbine structure modeling and stress combination are also addressed. The NREL-5MW "Hywind" Spar type wind turbine is adopted as study object. Time-domain dynamic coupled simulations are performed by a fully-coupled aero-hydro-servo-elastic tool, FAST, on the purpose of obtaining the dynamic characteristics of the floating wind turbine, and determining parameters for design load cases of finite element calculation. Then design load cases are identified, and finite element analyses are performed for these design load cases. The structural stresses due to wave-induced loads and wind-induced loads are calculated, and then combined to assess the structural strength of the floating wind turbine. The feasibility of the proposed structural strength analysis method for floating wind turbines is then validated.

  20. Towards Interactive Steering of a Very Large Floating Structure Code by Using HPC Parallelisation Strategies

    KAUST Repository

    Frisch, Jerome

    2012-09-01

    Very large floating structures (VLFSs) have been used for broad applications such as floating storage facilities, floating piers, floating bridges, floating airports, entertainment facilities, even habitation, and other purposes. Owing to its small bending rigidity, VLFS deforms elastically when subjected to wave action. This elastic deformation due to wave is called hydro elastic response and it can be obtained by solving the interaction between the surface wave and the floating structure in the frequency domain. In solving the fluid-structure interaction, the floating structure can be modelled by applying the finite element method, whereas the fluid part may be analyzed by using the Green\\'s function method. When using the Green\\'s function which satisfies the boundary condition on the free-surface, the sea bottom and that at infinite distance from the floating structure, the unknown parameters to be determined for the fluid part can be minimized to be only those associated with the wetted surface of the floating structure. However, in the evaluation of the Green\\'s function, extensive computation time O(N2) is needed (N is the number of unknowns). Therefore, acceleration techniques are necessary to tackle the computational complexity. Nowadays, standard multi-core office PCs are already quite powerful if all the cores can be used efficiently. This paper will show different parallelisation strategies for speeding up the Green\\'s function computation. A shared memory based implementation as well as a distributed memory concept will be analysed regarding speed-up and efficiency. For large computations, batch jobs can be used to compute detailed results in high resolution on a large computational cluster or supercomputer. Different speed-up computations on clusters will be included for showing strong speed-up results. © 2012 IEEE.

  1. USFWS/DU Floating Nest Structure Project Report: 1997 season and final summary

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report presents four-year results from a waterfowl floating nest structure project in the Morris Wetland District, Minnesota. The study was conducted from 1994...

  2. Transportation of Floating Structures by Using Newly Built Heavy Lifting Semi Vessel HYSY278

    Institute of Scientific and Technical Information of China (English)

    SUN Wei-ying; ZHANG Da-gang; FAN Zhi-xia

    2013-01-01

    Transportation of floating structures for long distance has always been associated with the use of heavy semi transport vessel.The requirements of this type of vessel are always special,and its availability is limited.To prepare for the future development of the South China Sea deepwater projects,COOEC has recently built a heavy lift transport vessel-Hai Yang Shi You 278 (HYSY278).This semi-submersible vessel has displacement capacity of 50k DWT,and a breath of 42 m.Understanding the vessel's applicability and preparing its use for future deepwater projects are becoming imminent need.This paper reviews the critical issues associated with the floating structure transportation and performs detailed analysis of two designed floating structures during transportation.The newly built COOEC transportation vessel HYSY278 will be used to dry transport the floating structures from COOEC fabrication yard in Qingdao to the oil field in the South China Sea.The entire process will start with load-out/float-offthe floating structures from the construction sites,offload the platform from the vessel if needed,dry transport floating structures through a long distance,and finally offload the platform.Both hydrodynamic and structural analyses are performed to evaluate transport vessel and floating structures.Critical issues associated with the transportation and offloading of platform from the vessel will be studied in detail.Detailed study is performed to evaluate the response of the system during this phase and additional work needed to make the vessel feasible for use of this purpose.The results demonstrate that with proper modifications,HYSY278 can effectively be used for transporting structures with proper arrangement and well-prepared operation.The procedure and details are presented on the basis of study results.Special attentions associated with future use will also be discussed based on the results from analysis.

  3. Surface and Internal Waves due to a Moving Load on a Very Large Floating Structure

    Directory of Open Access Journals (Sweden)

    Taro Kakinuma

    2012-01-01

    Full Text Available Interaction of surface/internal water waves with a floating platform is discussed with nonlinearity of fluid motion and flexibility of oscillating structure. The set of governing equations based on a variational principle is applied to a one- or two-layer fluid interacting with a horizontally very large and elastic thin plate floating on the water surface. Calculation results of surface displacements are compared with the existing experimental data, where a tsunami, in terms of a solitary wave, propagates across one-layer water with a floating thin plate. We also simulate surface and internal waves due to a point load, such as an airplane, moving on a very large floating structure in shallow water. The wave height of the surface or internal mode is amplified when the velocity of moving point load is equal to the surface- or internal-mode celerity, respectively.

  4. Wave response analyses of floating crane structure; Crane sen no jobu kozobutsu no haro oto

    Energy Technology Data Exchange (ETDEWEB)

    Nobukawa, H.; Takaki, M.; Kitamura, M.; Ahou, G. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering; Higashimura, M. [Fukada Salvage and Marine Works Co. Ltd., Osaka (Japan)

    1996-12-31

    Identifying a dynamic load acting on a lifted load in a floating crane moving in waves is important for preparing an operation manual for the floating crane. Analyses were made on motions in waves of a floating crane with a lifting load of 3,600 tons, with considerations given to deformation of the crane structure. Discussions were given on a dynamic load acting on a lifted load. If a case that considers elastic deformation in the crane structure is compared with a case that does not consider same in calculating hull motions of the floating crane, the difference between them is small if wave length {lambda} to the ship length L is about 0.5. However, if {lambda}/L is 1.0 and 1.5, the difference grows very large. Therefore, the effect of deformation in the crane structure on hull motions of the floating crane cannot be ignored in these cases. A dynamic load acting on a lifted load that considers deformation in the crane structure is about 5% of lifted weight in a headsea condition in which the wave height is 2 m and {lambda}/L is 1.5. As opposed, an estimated value of a dynamic load when the crane structure is regarded as a rigid body is 13%, which is 2.6 times as great as the case that considers deformation of the crane structure. 3 refs., 17 figs., 1 tab.

  5. An experimental study on two-story reinforced concrete box-shaped and truncated cone-shaped shear walls

    International Nuclear Information System (INIS)

    An experimental investigation has been performed upon shear wall specimens representing the inner and shield walls in a boiling water reactor (BWR) type reactor building. A set of three two-storey specimens were prepared. One is a sophisticated shear wall component composed of box-shaped and truncated cone-shaped walls interacting with each other. The other two are, respectively, box-shaped and truncated cone-shaped shear walls. A cyclic lateral loading program has been established from an analysis subjected to seismic excitation. The load-deflection characteristics, the deformation of the components, and the strain of concrete and reinforcing bars were examined. The results obtained from the sophisticated wall are compared with those obtained individually from the box-shaped and cone-shaped walls. Discussion on the observed characteristics leads to the evidence that the behaviors of the sophisticated wall can be successfully estimated from those of its corresponding individual wall components. (author)

  6. Structural analysis of floating offshore wind turbine tower based on flexible multibody dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kwang Phil; Jo, A Ra [Daewoo Shipbuilding and Marine Engineering, Co., Ltd., Seoul (Korea, Republic of); Cha, Ju Hwan [Mokpo Nat' l Univ., Muan (Korea, Republic of)

    2012-12-15

    In this study, we perform the structural analysis of a floating offshore wind turbine tower by considering the dynamic response of the floating platform. A multibody system consisting of three blades, a hub, a nacelle, the platform, and the tower is used to model the floating wind turbine. The blades and the tower are modeled as flexible bodies using three dimensional beam elements. The aerodynamic force on the blades is calculated by the Blade Element Momentum (BEM) theory with hub rotation. The hydrostatic, hydrodynamic, and mooring forces are considered for the platform. The structural dynamic responses of the tower are simulated by numerically solving the equations of motion. From the simulation results, the time history of the internal forces at the nodes, such as the bending moment and stress, are obtained. In conclusion, the internal forces are compared with those obtained from static analysis to assess the effects of wave loads on the structural stability of the tower.

  7. Structural analysis of floating offshore wind turbine tower based on flexible multibody dynamics

    International Nuclear Information System (INIS)

    In this study, we perform the structural analysis of a floating offshore wind turbine tower by considering the dynamic response of the floating platform. A multibody system consisting of three blades, a hub, a nacelle, the platform, and the tower is used to model the floating wind turbine. The blades and the tower are modeled as flexible bodies using three dimensional beam elements. The aerodynamic force on the blades is calculated by the Blade Element Momentum (BEM) theory with hub rotation. The hydrostatic, hydrodynamic, and mooring forces are considered for the platform. The structural dynamic responses of the tower are simulated by numerically solving the equations of motion. From the simulation results, the time history of the internal forces at the nodes, such as the bending moment and stress, are obtained. In conclusion, the internal forces are compared with those obtained from static analysis to assess the effects of wave loads on the structural stability of the tower

  8. Conceptual Design of a Floating Support Structure and Mooring System for a Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Berthelsen, Petter Andreas; Fylling, Ivar; Vita, Luca;

    2012-01-01

    This paper deals with the conceptual design of a floating support structure and mooring system for a 5MW vertical axis offshore wind turbine. The work is carried out as part of the DeepWind project, where the main objective is to investigate the feasibility of a floating vertical axis offshore wind...... turbine. The DeepWind concept consists of a Darrieus rotor mounted on a spar buoy support structure. The conceptual design is carried out in an iterative process, involving the different subcomponents. The present work is part of the first design iteration and the objective is to find a feasible floating...... response analysis programs for mooring system forces and vessel motions, and combines this with a gradient search method for solution of nonlinear optimization problems with arbitrary constraints. Two different mooring system configurations are considered: Chain systems with 3 and 6 lines, respectively....

  9. WindWaveFloat

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Alla [Principle Power Inc., Berkeley, CA (United States)

    2011-11-01

    Presentation from the 2011 Water Peer Review includes in which principal investigator Alla Weinstein discusses project progress in development of a floating offshore wind structure - the WindFloat - and incorporation therin of a Spherical Wave Energy Device.

  10. A case study of interior low-frequency noise from box-shaped bridge girders induced by running trains: Its mechanism, prediction and countermeasures

    Science.gov (United States)

    Zhang, Xun; Li, Xiaozhen; Hao, Hong; Wang, Dangxiong; Li, Yadong

    2016-04-01

    A side effect of high-speed railway and urban rail transit systems is the associated vibration and noise. Since the use of concrete viaducts is predominant in railway construction due to scarce land resources, low-frequency (20-200 Hz) structure-radiated noise from concrete bridges is a principal concern. Although it is the most commonly used bridge type, the mechanism of noise emission from box-shaped bridge girders when subjected to impact forces from moving trains, which sounds like beating a drum, has not been well studied. In this study, a field measurement was first made on a simply-supported box-shaped bridge to record the acceleration of the slabs and the associated sound pressures induced by running trains. These data indicated that a significant beat-wave noise occurred in the box-shaped cavity when the train speed was around 340 km/h, which arose from the interference between two sound waves of 75.0 Hz and 78.8 Hz. The noise leakage from the bridge expansion joint was serious and resulted in obvious noise pollution near the bridge once the beat-wave noise was generated in the cavity. The dominant frequency of the interior noise at 75.0 Hz was confirmed from the spectrum of the data and the modal analysis results, and originated from the peak vibration of the top slab due to resonance and the first-order vertical acoustic mode, which led to cavity resonance, amplifying the corresponding noise. The three-dimensional acoustic modes and local vibration modes of the slab were calculated by using the finite element method. A simplified vehicle-track-bridge coupling vibration model was then developed to calculate the wheel-rail interaction force in a frequency range of 20-200 Hz. Numerical simulations using the boundary element method confirmed the cavity resonance effect and the numerical results agreed well with the data. Based on the calibrated numerical model, three noise reduction measures, i.e., adding a horizontal baffle in the interior cavity, narrowing

  11. Dynamic load mitigation for floating offshore wind turbines supported by structures with mooring lines

    OpenAIRE

    Luo, Ningsu; Pacheco Garcés, José Luis; Vidal Seguí, Yolanda; Zapateiro, Mauricio

    2012-01-01

    In recent years, the offshore wind industry has experienced significant growth with the installation of offshore wind farms in shallow water (such as in Denmark). However, almost all of offshore wind turbines to date are mounted on fixed-bottom support structures in water depths of less than 50m, which are not feasible off the coasts of the United States, China, Japan, Norway and Spain, among others. As a potential solution, wind turbines can be mounted on floating support structures an...

  12. Experimental validation of a Fluid-Structure interaction model for simulating offshore floating wind turbines

    Science.gov (United States)

    Calderer, Antoni; Feist, Christ; Ruehl, Kelley; Guala, Michele; Sotiropoulos, Fotis

    2014-11-01

    A series of experiments reproducing a floating wind turbine in operational sea conditions, conducted in the St. Anthony Falls Lab. wave facility, are employed to validate the capabilities of the recently developed FSI-Levelset-CURVIB method of Calderer, Kang and Sotiropoulos (JCP 2014) to accurately predict turbine-wave interactions. The numerical approach is based on solving the Navier-Stokes equations coupled with the level set method, which is capable of carrying out LES of two-phase flows (air and water) with complex floating structures and waves. The investigated floating turbine is a 1:100 Froude scaled version of the 13.2 MW prototype designed by Sandia National Lab; it is installed on a cylindrical barge style platform which is restricted to move with two degrees of freedom, heave and pitch in the vertical plane defined by the direction of the propagating 2D waves. The computed turbine kinematics as well as the free surface elevation results are compared with the experimental data for different free decay tests and wave conditions representative of the Maine and the Pacific North West coasts. The comparison shows promising results indicating the validity of the model for simulating operational floating turbines. This work is supported by the US Department of Energy (DE-EE0005482), the University of Minnesota IREE program, and the Minnesota Supercomputing Institute.

  13. Floating production storage offloading unit structural fatigue analysis

    OpenAIRE

    Kattoua, K.

    2003-01-01

    This thesis examines the fatigue behaviour of FPSO structures. It has been compiled as a result of theoretical, analytical and experimental study. The Finite Element approach has been utilized to analyse the FPSO's structure. It is intended that this particular work will enable further computer simulations for fatigue assessment to be carried out. The thesis starts with the development of the general arrangement, structure and typical details of the City FPSO. The applied loads are then revie...

  14. Space Station Freedom structure floating potential and the probability of arcing

    Science.gov (United States)

    Hastings, Daniel E.; Cho, Mengu; Wang, Jiong

    1992-01-01

    The interaction between a space system and the space environment has been one of the driving questions for the design of spacecraft since the dawn of the space age. The Space Station Freedom will represent a significant increase in spacecraft size, power, and activity relative to spacecraft that are currently in orbit. The structure floating potential on Space Station Freedom is studied with simple analytical models of the current collection. The probability of arcing due to dielectric breakdown is assessed.

  15. Experimental RAO’s analysis of a monolithic concrete spar structure for offshore floating wind turbines

    OpenAIRE

    Campos Hortigüela, Alexis; Molins i Borrell, Climent; Gironella Cobos, Xavier; Trubat Casal, Pau; Alarcón Fernández, Daniel

    2015-01-01

    Nowadays the offshore wind energy market is clearly oriented to be extended around the world. Bottom fixed solutions for supporting offshore wind turbines are useful in shallow waters which are available in a limited extent unless a continental shelf exists. Considering the Oil & Gas background knowledge, move from bottom fixed solutions to floating solutions is not a technical challenge, but the cost of each structure in terms of industry profit is currently the main ...

  16. Enhanced lines and box-shaped features in the gamma-ray spectrum from annihilating dark matter in the NMSSM

    Science.gov (United States)

    Cerdeño, D. G.; Peiró, M.; Robles, S.

    2016-04-01

    We study spectral features in the gamma-ray emission from dark matter (DM) annihilation in the Next-to-Minimal Supersymmetric Standard Model (NMSSM), with either neutralino or right-handed (RH) sneutrino DM . We perform a series of scans over the NMSSM parameter space, compute the DM annihilation cross section into two photons and the contribution of box-shaped features, and compare them with the limits derived from the Fermi-LAT search for gamma-ray lines using the latest Pass 8 data. We implement the LHC bounds on the Higgs sector and on the masses of supersymmetric particles as well as the constraints on low-energy observables. We also consider the recent upper limits from the Fermi-LAT satellite on the continuum gamma-ray emission from dwarf spheroidal galaxies (dSphs). We show that in the case of the RH sneutrino the constraint on gamma-ray spectral features can be more stringent than the dSph bounds. This is due to the Breit-Wigner enhancement near the ubiquitous resonances with a CP even Higgs and the contribution of scalar and pseudoscalar Higgs final states to box-shaped features. By contrast, for neutralino DM, the di-photon final state is only enhanced in the resonance with a Z boson and box-shaped features are even more suppressed. Therefore, the observation of spectral features could constitute a discriminating factor between both models. In addition, we compare our results with direct DM searches, including the SuperCDMS and LUX limits on the elastic DM-nucleus scattering cross section and show that some of these scenarios would be accessible to next generation experiments. Thus, our findings strengthen the idea of complementarity among distinct DM search strategies.

  17. Effects of fundamental structure parameters on dynamic responses of submerged floating tunnel under hydrodynamic loads

    Institute of Scientific and Technical Information of China (English)

    Xu Long; Fei Ge; Lei Wang; Youshi Hong

    2009-01-01

    This paper investigates the effects of structure parameters on dynamic responses of submerged floating tunnel (SFT) under hydrodynamic loads. The structure parameters includes buoyancy-weight ratio (BWR), stiffness coefficients of the cable systems, tunnel net buoyancy and tunnel length. First, the importance of structural damp in relation to the dynamic responses of SFT is demonstrated and the mechanism of structural damp effect is discussed. Thereafter, the fundamental structure parameters are investi-gated through the analysis of SFT dynamic responses under hydrodynamic loads. The results indicate that the BWR of SFT is a key structure parameter. When BWR is 1.2, there is a remarkable trend change in the vertical dynamic response of SFT under hydrodynamic loads. The results also indicate that the ratio of the tunnel net buoyancy to the cable stiffness coefficient is not a characteristic factor affecting the dynamic responses of SFT under hydrodynamic loads.

  18. Systematic analysis on mooring systems of floating structures; Futai keiryuho ni kansuru keitoteki kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, K.; Suzuki, H.; Ide, T. [The University of Tokyo, Tokyo (Japan)

    1996-12-31

    Discussed herein are mooring performance requirements of the new types of marine structures now proposed, and characteristic ranges and future expansion potential of the existing mooring systems. The mooring systems studied for floating structures are catenary, single point (multi-leg and single-leg types), fixed structure with fender and tension leg mooring systems. The studied items include extraction of the elements that constitute rigidity of the spring for horizontal mooring, survey on and data collection for each element, determination of element ranges, programs for mooring analysis, assessment of mooring characteristic ranges, and potential development of the characteristic ranges. It is concluded that the existing systems with their current characteristic ranges and future possibility are insufficient for the future marine structures. It is therefore necessary to develop new mooring concepts, instead of expanding the current concepts, in order to meet the mooring performance requirements for the new marine structures. 14 refs., 9 figs., 11 tabs.

  19. An Active helideck testbed for floating structures based on a Stewart-Gough platform

    OpenAIRE

    Campos Bonilla, Aníbal Alexandre; Quintero Ruiz, Jacqueline; Saltaren Pazmiño, Roque Jacinto; Ferre Perez, Manuel; Aracil Santonja, Rafael

    2008-01-01

    A parallel robot testbed based on Stewart-Gough platform called Active-helideck is designed, developed and tested as a helicopter floating helideck. The objective of this testbed is to show the advantages of helicopters that use an active helideck upon landing on and taking off from ships or from offshore structures. Active-helideck compensates simulated movements of a ship at sea. The main goal of this study is to maintain the robot’s end effector (helideck) in a quasi-static position in acc...

  20. Bio-Argo Floats Reveal Subsurface Structure of Indian Ocean Eddies

    Science.gov (United States)

    Strutton, P. G.; Phillips, H. E.; Trull, T. W.; Duran, E.; Pump, S.

    2015-12-01

    There is increasing recognition that eddies modulate open ocean productivity, and that this influence depends on both eddy source and their evolution. Eddies in the southeast Indian Ocean have been recognised, from satellite remote sensing of sea surface height and ocean colour, as important pathways for the westward transport of elevated biomass from the eastern boundary Leeuwin Current into the oligotrophic South Indian Ocean. Further it has been hypothesized that, in some eddies, processes at the base of the mixed layer stimulate productivity and sustain phytoplankton biomass for much longer than would be expected from westward advection alone. Here we present high-frequency profiles of temperature, salinity, chlorophyll, backscatter and oxygen from autonomous floats in anti-cyclonic and cyclonic eddies in the South Indian Ocean. Satellite sea surface height data confirmed that the floats remained trapped in their respective eddies from winter to early summer, sampling the upper 300 m of the water column 6-8 times per day. The eddies were larger than average for this region, with mean amplitude and radius of 18.1 (19.3) cm and 143 (97) km for the anticyclonic (cyclonic) eddies. The total concentration of chlorophyll in the mixed layer remained relatively constant, although its vertical distribution changed over time. From September to October, it was evenly distributed throughout the mixed layer of both eddies. With the onset of spring warming, the chlorophyll became concentrated at greater depth with less chlorophyll at the surface. Satellite measurements of surface chlorophyll were 3-5 times lower than the float surface measurement throughout the record, partly because of the vertical structure in chlorophyll. There was no significant change in oxygen saturation state coincident with high phytoplankton concentrations at depth, indicating no net community production. The eddies appear to self-sustain their biomass.

  1. The effect of metal field plates on multiguard structures with floating p+ guard rings

    International Nuclear Information System (INIS)

    The performance and stability of silicon diode detectors can be improved by implementing guard ring structures around the active detector area. The purpose of this work is to study design parameters influencing the performance of multiguard structures, especially the effect of metal field plates. An important feature is the potential distribution in the multiguard ring structure which depends on the bulk doping concentration, the oxide charge, the size of the gap between guard rings and the field-plate design. We have made a systematic investigation of the effect of distance between floating p+ guard rings with two different metal field plate designs. We have also varied the width of the field plates and studied the effect of gamma irradiation. Numerical simulations have been done to compare with results from the experimental potential distributions between guard rings. (orig.)

  2. Manipulation of a free-floating object using a macro/mini-manipulator with structural flexibility

    Science.gov (United States)

    Stevens, Homer Darling

    A new generation of operational robots is being developed that offers many exciting capabilities such as the capture of errant satellites, and the removal of nuclear waste from a large temporary storage tank. These tasks illuminate the particularly challenging problem of bringing a robot that exhibits structural flexibility into stable contact with free-floating objects in the environment. Interaction with a dynamic object imposes a relationship between the manipulator's position and the contact force that is well modeled as a generalized impedance. Controlling the manipulator's dynamic response to follow that of a specified impedance function complementary to the impedance of the dynamic object enables smooth interaction with that object. This type of control, called impedance control, provides a unified approach to both unconstrained and constrained motion in an uncertain, dynamic environment. The benefits of impedance control have been demonstrated using "rigid" robots, that is robots where the fundamental frequency of the structural vibration modes is several orders of magnitude higher than the task bandwidth. This research extends the application of impedance control to a large, structurally flexible macro-manipulator carrying a small rigid mini-manipulator. One example of this class of robots is the Space Station Remote Manipulator System and Special Purpose Dextrous Manipulator combination currently under development. This dissertation presents new synthesis concepts that enable impedance control to be achieved for the first time using a structurally flexible macro/mini-manipulator. The theoretical developments are experimentally demonstrated using a macro/mini-manipulator with significant structural flexibility. These results demonstrate fine, gentle contact with an object fixed in the environment, gentle initial contact and the firm maintenance of contact with an object completely free to move in the environment, and the prompt capture, by stopping all

  3. Time Domain Simulation of Transient Responses of Very Large Floating Structures Under Unsteady External Loads

    Institute of Scientific and Technical Information of China (English)

    QIU Liu-chao; LIU Hua

    2005-01-01

    A time domain finite element method (FEM) for the analysis of transient elastic response of a very large floating structure (VLFS) subjected to arbitrary time-dependent external loads is presented. This method is developed directly in time domain and the hydrodynamic problem is formulated based on linear, inviscid and slightly compressible fluid theory and the structural response is analyzed on the thin plate assumption. The time domain finite element procedure herein is validated by comparing numerical results with available experimental data. Finally, the transient elastic response of a pontoon-type VLFS under the landing of an airplane is computed by the proposed time domain FEM. The time histories of the applied force and the position and velocity of an airplane during landing are modeled with data from a Boeing 747-400 jumbo jet.

  4. Structural features of Ge(Ga) single crystals grown by the floating zone method in microgravity

    Science.gov (United States)

    Prokhorov, I. A.; Zakharov, B. G.; Senchenkov, A. S.; Egorov, A. V.; Camel, D.; Tison, P.

    2008-11-01

    Structural features of the Ge(Ga) single crystal grown by the floating zone (FZ) method in microgravity environment aboard the FOTON-9 spacecraft are investigated by methods of X-ray topography, double-crystal diffractometry, selective chemical etching and spreading resistance measurements. It is established that the crystal structure is characterized by the presence of an incompletely melted region and defects caused by its formation. Growth striations revealed in regrown part of the crystal, testify to development of non-stationary capillary Marangoni convection in melt at the realized parameters of FZ remelting under space conditions. Periodicity of the growth striations is compared to frequency characteristics of heat flux pulsations through the crystallization front, found as a result of numerical simulation of melt hydrodynamics.

  5. Water-cooled lithium-lead box-shaped blanket concept for Demo: thermo-mechanical optimization and manufacturing sequence proposal

    International Nuclear Information System (INIS)

    The development of the water-cooled lithium-lead box-shaped blanket concept for DEMO has now reached the stage of thermo-mechanical optimization. In the previous design phases the preliminary dimensioning of the cooling circuit has permitted to define the water proportions required in the breeder region and to demonstrate, after a minimization of steel proportion and thicknesses, that this concept could reach tritium breeding self-sufficiency. In the present analysis the location of the coolant pipes has been optimized for the whole equatorial plane cross-section of both inboard and outboard segments in order to maintain the maximum Pb-17Li/steel interface temperature below 480 deg C and to minimize the thermal gradients along the steel structures. The consequent thermo-mechanical analysis has shown that the thermal stresses always remain below the allowable limits. Segment fabricability and removal are the next design issues to be analyzed. Within this strategy, a first manufactury sequence for the outboard segment is proposed

  6. Evaluation on the effect of tsunami and seaquake on the floating structure; Tsunami kaishin no futai ni taisuru eikyo hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, K.; Suzuki, H.; Hosomi, I. [The University of Tokyo, Tokyo (Japan); Nahata, H. [The Long-Term Credit Bank of Japan, Ltd., Tokyo (Japan)

    1996-12-31

    The effects of tsunami and seaquake on large floating structures are theoretically studied, where these effects are followed in terms of local strength using the equation proposed by Sells to predict surface shapes changed by seaquake-caused uplift of the seabottom. The equation is combined with the one for tsunami propagation, to better predict the tsunami motion. The simulation results indicate the necessity of considering the effects of tsunami for the design of a large floating structure. The authors discuss that the effect of tsunami is minimized when a floating structure is set at a depth of at least 40 to 50m, chain length should be determined by equalizing the breaking weight with the load at which the structure starts to move, and a structure should be set at a position where it is not attacked by transverse waves. They also discuss that seaquake intensity should be predicted by the equation of motion of compressible fluid, and, noting local strength of a floating structure, it will not be damaged when it is at least 16mm thick under the conditions of 2m as seabottom uplift and 0.5m as draft depth. 15 refs., 9 figs., 2 tabs.

  7. Numerical Analysis of a Large Floating Wave Energy Converter with Adjustable Structural Geometry

    DEFF Research Database (Denmark)

    Ferri, Francesco; Pecher, Arthur Francois Serge; Kofoed, Jens Peter

    2015-01-01

    The current cost of energy (CoE) from wave energy converters (WECs) is still significantly higher than other renewable energy resources, thus the sector has not yet reached a competitive level. WECs have a relative small turnover compared to the high capital cost, which to a large extent is drive...... compare two different configurations of the Weptos machine, using the cost of energy (CoE) as a base of comparison. The numerical results are obtained via a multi-body analysis carried out in frequency domain....... by the structural loads in extreme conditions. TheWeptos is a large floating WEC, with multiple absorbers, which has proven to be a serious candidate for the renewable energy market, due to both relevant power performance and reduced cost if compared with other WECs. The scope of this article is to...

  8. Predicting patchy particle crystals: variable box shape simulations and evolutionary algorithms.

    Science.gov (United States)

    Bianchi, Emanuela; Doppelbauer, Günther; Filion, Laura; Dijkstra, Marjolein; Kahl, Gerhard

    2012-06-01

    We consider several patchy particle models that have been proposed in literature and we investigate their candidate crystal structures in a systematic way. We compare two different algorithms for predicting crystal structures: (i) an approach based on Monte Carlo simulations in the isobaric-isothermal ensemble and (ii) an optimization technique based on ideas of evolutionary algorithms. We show that the two methods are equally successful and provide consistent results on crystalline phases of patchy particle systems. PMID:22697525

  9. Predicting Patchy Particle Crystals: Variable Box Shape Simulations and Evolutionary Algorithms

    OpenAIRE

    2012-01-01

    We consider several patchy particle models that have been proposed in literature and we investigate their candidate crystal structures in a systematic way. We compare two different algorithms for predicting crystal structures: (i) an approach based on Monte Carlo simulations in the isobaric-isothermal ensemble and (ii) an optimization technique based on ideas of evolutionary algorithms. We show that the two methods are equally successful and provide consistent results on crystalline phases of...

  10. Comparison of linear spring and nonlinear FEM methods in dynamic coupled analysis of floating structure and mooring system

    Science.gov (United States)

    Kim, Byoung Wan; Sung, Hong Gun; Kim, Jin Ha; Hong, Sa Young

    2013-10-01

    This paper compares the dynamic coupled behavior of floating structure and mooring system in time domain using two numerical methods for the mooring lines such as the linear spring method and the nonlinear FEM (Finite Element Method). In the linear spring method, hydrodynamic coefficients and forces on the floating body are calculated using BEM (Boundary Element Method) and the time domain equation is derived using convolution. The coupled solution is obtained by simply adding the pre-determined spring constants of the mooring lines into the floating body equation. In FEM, the minimum energy principle is applied to formulate the nonlinear dynamic equation of the mooring system with a discrete numerical model. The ground contact model and Morison formula for drag forces are also included in the formulation. The coupled solution is obtained by iteratively solving the floating body equation and the FEM equation of the mooring system. Two example structures such as weathervane ship and semi-submersible structure are analyzed using linear spring and nonlinear FEM methods and the difference of those two methods are presented. By analyzing the cases with or without surge-pitch or sway-roll coupling stiffness of mooring lines in the linear spring method, the effect of coupling stiffness of the mooring system is also discussed.

  11. Design and evaluation of an innovative floating and bioadhesive multiparticulate drug delivery system based on hollow structure.

    Science.gov (United States)

    Zhang, Chungang; Tang, Jingya; Liu, Dechun; Li, Xuetao; Cheng, Lan; Tang, Xing

    2016-04-30

    In this study a gastric-retentive delivery system was prepared by a novel method which is reported here for the first time. An innovative floating and bioadhesive drug delivery system with a hollow structure was designed and prepared. The floating and bioadhesive drug delivery system was composed of a hollow spherical shell, a waterproof layer (Stearic acid), a drug layer (Ofloxacin), a release retarding film (the novel blended coating materials) and a bioadhesive layer (Carbomer 934P) prepared by using a liquid multi-layering process. A novel blended coating material was designed and investigated to solve the problem of the initial burst release of the formulation and the release mechanism of the novel material was analyzed in this study. The optimized formulation provided the sustained release characteristic and was able to float for 24h. The SEM cross-section images showed that the particulates were hollow with a spherical shell. X-ray images and pharmacokinetic studies (Frel=124.1±28.9%) in vivo showed that the gastric-retentive delivery system can be retained in the stomach for more than 6h. The floating and bioadhesive particulate drug delivery system based on a hollow structure with a dual function presented here is a viable alternative to other for gastroretentive drug delivery system. PMID:26943975

  12. Enhanced lines and box-shaped features in the gamma-ray spectrum from annihilating dark matter in the NMSSM

    CERN Document Server

    Cerdeno, D G; Robles, S

    2015-01-01

    We study spectral features in the gamma-ray emission from dark matter (DM) annihilation in the Next-to-Minimal Supersymmetric Standard Model (NMSSM), with either neutralino or right-handed (RH) sneutrino DM. We perform a series of scans over the NMSSM parameter space, compute the DM annihilation cross section into two photons and the contribution of box-shaped features, and compare them with the limits derived from the Fermi-LAT search for gamma-ray lines using the latest Pass 8 data. We implement the LHC bounds on the Higgs sector and on the masses of supersymmetric particles as well as the constraints on low-energy observables. We also consider the recent upper limits from the Fermi-LAT satellite on the continuum gamma-ray emission from dwarf spheroidal galaxies (dSphs). We show that in the case of the RH sneutrino the constraint on gamma-ray spectral features can be more stringent than the dSphs bounds. This is due to the Breit-Wigner enhancement near the ubiquitous resonances with a CP even Higgs and the ...

  13. Elasto-capillary collapse of floating structures - Non-linear response of elastic structures under capillary forces

    CERN Document Server

    Adami, N; Roman, B; Bico, J; Caps, H

    2013-01-01

    Flexible rings and rectangle structures floating at the surface of water are prone to deflect under the action of surface pressure induced by the addition of surfactant molecules on the bath. While the frames of rectangles bend inward or outward for any surface pressure difference, circles are only deformed by compression beyond a critical buckling load. However, compressed frames also undergo a secondary buckling instability leading to a rhoboidal shape. Following the pioneering works of \\cite{Hu} and \\cite{Zell}, we describe both experimentally and theoretically the different elasto-capillary deflection and buckling modes as a function of the material parameters. In particular we show how this original fluid structure interaction may be used to probe the adsorption of surfactant molecules at liquid interfaces.

  14. Experimental Research on the Dynamic Response of Floating Structures with Coatings Subjected to Underwater Explosion

    Directory of Open Access Journals (Sweden)

    Feng Xiao

    2014-01-01

    Full Text Available This paper presents an experimental investigation into the dynamic response of three free floating stiffened metal boxes with protective coatings subjected to underwater explosion (UNDEX. One box was kept intact while the other two were, respectively, covered with monolithic coatings and chiral honeycomb coatings. Three groups of live fire tests with different attack angles and stand-off distances were conducted. The acceleration on the stiffener and strain peak on the bottom hull were selected as the major comparative criterions. Test results show that the impulse transmitted to the structure at the initial stage can be reduced, owing to the coating flexibility and fluid-structure interaction mechanism. Consequently, the acceleration peaks induced by both shock wave and bubble pulse were reduced. The shock environment can be more effectively improved by honeycomb coating when compared with monolithic coating. Most of the strain peaks decreased to a certain extent, but some of them were notably manifested, especially for honeycomb coating. The test affirms the fact that soft coating can cause stress concentration on the shell that is in direct contact with the coating due to the impedance mismatch between the interfaces of materials. A softer rubber coating induces a greater magnitude of strain.

  15. Micromechanisms with floating pivot

    Science.gov (United States)

    Garcia, Ernest J.

    2001-03-06

    A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use floating pivot structures to relieve some of the problems encountered in the use of solid flexible pivots.

  16. Hydroelastic analysis of a very large floating structure edged with a pair of submerged horizontal plates

    Science.gov (United States)

    Ma, Zhe; Cheng, Yong; Zhai, Gangjun; Ou, Jinping

    2015-04-01

    This paper is concerned with the hydroelastic problem of a very large pontoon-type floating structure (VLFS) edged with a pair of submerged horizontal plates, which is a combination of perforated and non-perforated plates attached to the for-end and back-end of the VLFS. For the hydroelastic analysis, the fluid is assumed to be ideal and its motion is irrotational so that a velocity potential exists. The VLFS is modeled as an elastic plate according to the classical thin plate theory. The fluid-structure interaction problem is separated into conventional hydrodynamics and structure dynamics by using modal expansion method in the frequency-domain. It involves, firstly, the deflection of the VLFS, which is expressed by a superposition of modal functions and corresponding modal amplitudes. Then the boundary element method is used to solve the integral equations of diffraction and radiation on the body surface for the velocity potential, whereas the vibration equation is solved by the Galerkin's method for modal amplitudes, and then the deflection is obtained by the sum of multiplying modal functions with modal amplitudes. This study examines the effects of the width and location of the non-perforated horizontal plates on the hydroelastic response of the VLFS, then the performance of perforated plates is investigated to reduce the motion near the fore-end of the VLFS. Considering the advantages and disadvantages of submerged plates without and with cylindrical holes, we propose a simple anti-motion device, which is a combination of a pair of perforated and non-perforated plates attached to the for-end and back-end of the VLFS. The effectiveness of this device in reducing the deformation and bending moment of the VLFS has been confirmed, and is compared with the results in cases without and with the submerged horizontal plates by the analysis in this paper.

  17. Asset Decommissioning Risk Metrics for Floating Structures in the Gulf of Mexico.

    Science.gov (United States)

    Kaiser, Mark J

    2015-08-01

    Public companies in the United States are required to report standardized values of their proved reserves and asset retirement obligations on an annual basis. When compared, these two measures provide an aggregate indicator of corporate decommissioning risk but, because of their consolidated nature, cannot readily be decomposed at a more granular level. The purpose of this article is to introduce a decommissioning risk metric defined in terms of the ratio of the expected value of an asset's reserves to its expected cost of decommissioning. Asset decommissioning risk (ADR) is more difficult to compute than a consolidated corporate risk measure, but can be used to quantify the decommissioning risk of structures and to perform regional comparisons, and also provides market signals of future decommissioning activity. We formalize two risk metrics for decommissioning and apply the ADR metric to the deepwater Gulf of Mexico (GOM) floater inventory. Deepwater oil and gas structures are expensive to construct, and at the end of their useful life, will be expensive to decommission. The value of proved reserves for the 42 floating structures in the GOM circa January 2013 is estimated to range between $37 and $80 billion for future oil prices between 60 and 120 $/bbl, which is about 10 to 20 times greater than the estimated $4.3 billion to decommission the inventory. Eni's Allegheny and MC Offshore's Jolliet tension leg platforms have ADR metrics less than one and are approaching the end of their useful life. Application of the proposed metrics in the regulatory review of supplemental bonding requirements in the U.S. Outer Continental Shelf is suggested to complement the current suite of financial metrics employed. PMID:25692712

  18. FLOAT Project

    DEFF Research Database (Denmark)

    Sørensen, Eigil V.; Aarup, Bendt

    The objective of the FLOAT project is to study the reliability of high-performance fibre-reinforced concrete, also known as Compact Reinforced Composite (CRC), for the floats of wave energy converters. In order to reach a commercial breakthrough, wave energy converters need to achieve a lower price...

  19. Structural Dynamic behaviour of a floating platform for Offshore wind turbines

    OpenAIRE

    Abón Olivera, Guillermo

    2013-01-01

    In this minor thesis, the use of concrete as material for floating wind platforms is proposed as an alternative that can provide, great  resistance to corrosion and virtually non maintenance.  After selecting the best suitable floating platform type for shallow waters a static analysis is done in order to choose the geometry and dimensions that best fits the needs expressed.  Then with the selected model, a dynamic analysis is  performed in order to check the platform interaction with waves. ...

  20. Smart structural control strategies for offshore wind power generation with floating wind turbines

    OpenAIRE

    Luo, Ningsu; Pacheco, Lluís; Vidal Seguí, Yolanda; Li, Hui

    2012-01-01

    In recent years, wind energy is the fastest growing clean and renewable energy source in the world. However, most of the wind farm development has been limited to the land space and shallow water regions. Recently, several European countries (including Spain), USA and Japan started to plan floating offshore wind farms. In June of 2009, the first floating offshore wind turbine (Hywind) of the world was installed by Statoil-Hydro and Siemens on the coast of Karmøy, near the port of Bergen...

  1. On the prediction of hydroelastic behaviors of a huge floating structure in waves. 2nd Report; Choogata futai no harochu dansei kyodo no suiteiho ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Murai, M.; Kagemoto, H.; Fujino, M. [The University of Tokyo, Tokyo (Japan)

    1997-08-01

    On the hydroelastic behaviors of a huge floating structure, a mutual interaction theory based on the area division method is used for the analysis of a fluid problem and a mode analysis method is used for the analysis of deformation. On the continuous deformation of a floating structure, the structure is considered as a set of partial structures obtained when the plane shape was divided into squares and discretely handled as a series of rigid motions in the small partial structures obtained by dividing the partial structures more finely. The experimental result in a water tank and the distribution method at a singular point were compared on the deformation of the elastic floating structure estimated by calculation based on this formulation. The result showed that the estimation method on the hydroelastic problem proposed in this paper is valid. On the prediction of hydroelastic behaviors of a huge floating structure, various calculation examples indicate that the hydroelastic behavior is not only the relation between the structure length and wavelength, but also that the bending rigidity of a structure is a very important factor. For a huge floating structure in the 5,000 m class, up to shorter wavelength of about {lambda}/L = 1/100 must be investigated. 6 refs., 14 figs., 5 tabs.

  2. Fluid-structure interaction simulation of floating structures interacting with complex, large-scale ocean waves and atmospheric turbulence

    CERN Document Server

    Calderer, Antoni; Shen, Lian; Sotiropoulos, Fotis

    2016-01-01

    We develop a numerical method for simulating coupled interactions of complex floating structures with large-scale ocean waves and atmospheric turbulence. We employ an efficient large-scale model to develop offshore wind and wave environmental conditions, which are then incorporated into a high resolution two-phase flow solver with fluid-structure interaction (FSI). The large-scale wind-wave interaction model is based on the two-fluid dynamically-coupled approach of Yang and Shen (2011), which employs a high-order spectral method for simulating the water motion and a viscous solver with undulatory boundaries for the air motion. The two-phase flow FSI solver, developed by Calderer, Kang, and Sotiropoulos (2014), is based on the level set method and is capable of simulating the coupled dynamic interaction of arbitrarily complex bodies with airflow and waves. The large-scale wave field solver is coupled with the near-field FSI solver by feeding into the latter waves via the pressure-forcing method of Guo and Shen...

  3. Coupled fluid-structure interaction simulation of floating offshore wind turbines and waves: a large eddy simulation approach

    International Nuclear Information System (INIS)

    We develop a computational framework for simulating the coupled interaction of complex floating structures with large-scale ocean waves and atmospheric turbulent winds. The near-field approach features a partitioned fluid-structure interaction model (FSI) combining the curvilinear immersed boundary (CURVIB) method of Borazjani and Sotiropoulos (J. Comput. Phys. 2008) and the two-phase flow level set formulation of Kang and Sotiropoulos (Adv. in Water Res. 2012) and is capable of solving complex free-surface flows interacting non-linearly with complex real life floating structures. The near-field solver is coupled with a large-scale wave and wind model based on the two-fluid approach of Yang and Shen (J. Comput. Phys. 2011) which integrates a viscous Navier-Stokes solver with undulatory boundaries for the motion of the air and an efficient potential-flow based wave solver. The large-scale turbulent wind is incorporated from the far-field solver to the near-field solver by feeding into the latter inlet boundary conditions. The wave field is incorporated to the near-field solver by using the pressure-forcing method of Guo and Shen (J. Comput. Phys. 2009) which has been appropriately adapted to the level set method. The algorithm for coupling the two codes has been validated for a variety of wave cases including a broadband spectrum showing excellent agreement when compared to theoretical results. Finally, the capabilities of the numerical framework are demonstrated by carrying out large eddy simulation (LES) of a floating wind turbine interacting with realistic ocean wind and wave conditions

  4. Coupled fluid-structure interaction simulation of floating offshore wind turbines and waves: a large eddy simulation approach

    Science.gov (United States)

    Calderer, Antoni; Guo, Xin; Shen, Lian; Sotiropoulos, Fotis

    2014-06-01

    We develop a computational framework for simulating the coupled interaction of complex floating structures with large-scale ocean waves and atmospheric turbulent winds. The near-field approach features a partitioned fluid-structure interaction model (FSI) combining the curvilinear immersed boundary (CURVIB) method of Borazjani and Sotiropoulos (J. Comput. Phys. 2008) and the two-phase flow level set formulation of Kang and Sotiropoulos (Adv. in Water Res. 2012) and is capable of solving complex free-surface flows interacting non-linearly with complex real life floating structures. The near-field solver is coupled with a large-scale wave and wind model based on the two-fluid approach of Yang and Shen (J. Comput. Phys. 2011) which integrates a viscous Navier-Stokes solver with undulatory boundaries for the motion of the air and an efficient potential-flow based wave solver. The large-scale turbulent wind is incorporated from the far-field solver to the near-field solver by feeding into the latter inlet boundary conditions. The wave field is incorporated to the near-field solver by using the pressure-forcing method of Guo and Shen (J. Comput. Phys. 2009) which has been appropriately adapted to the level set method. The algorithm for coupling the two codes has been validated for a variety of wave cases including a broadband spectrum showing excellent agreement when compared to theoretical results. Finally, the capabilities of the numerical framework are demonstrated by carrying out large eddy simulation (LES) of a floating wind turbine interacting with realistic ocean wind and wave conditions.

  5. Structural response analysis of very large floating structures in waves using one-dimensional finite element model; Ichijigen yugen yoso model ni yoru choogata futai no harochu kozo oto kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Fujikubo, M.; Yao, T.; Oida, H. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering

    1996-12-31

    Formulation was made on a one-dimensional beam finite element which is effective in analyzing structural response of very large floating structures by modeling them on beams on an elastic foundation. This element allows strict solution of vibration response in the beams on the elastic foundation to be calculated efficiently for a case where mass and rigidity change in the longitudinal direction. This analysis method was used to analyze structural response of a large pontoon-type floating structure to investigate mass in the end part for the structural response and the effect of decay while passing the structure. With a pontoon-type floating structure, reduction in bends and bending stress in the end part of the floating structure is important in designing the structure. Reducing the mass in the end part is effective as a means to avoid resonance in these responses and reduce the responses. Increase in rigidity of a floating structure shifts the peak in quasi-static response to lower frequency side, and reduces response in resonance, hence it is advantageous for improving the response. Since incident waves decay while passing through the floating structure, response in the lower wave side decreases. The peak frequency in the quasi-static response also decreases at the end part of the structure in the upper wave side due to decay in wave force. 7 refs., 11 figs., 1 tab.

  6. Fluid-structure interaction simulation of floating wind turbines interacting with complex, large-scale ocean waves

    Science.gov (United States)

    Calderer, Antoni; Guo, Xin; Shen, Lian; Sotiropoulos, Fotis

    2013-11-01

    We develop a numerical method for simulating coupled interactions of complex floating structures with large-scale ocean waves and atmospheric turbulence. The Fluid-Structure Interaction (FSI) solver integrates the curvilinear immersed boundary method of Borazjani et al. (JCP 2008) with the level-set method of Kang et al. (Adv. in Water Res. 2012) and is capable of simulating the coupled dynamic interaction of arbitrarily complex bodies with airflow and waves. The large-scale wave model is based on the two-fluid coupled approach of Yang et al. (JCP 2011), which employs a high-order spectral method for simulating the water motion and a viscous solver with undulatory boundaries for the air motion. The large-scale wave field solver is coupled with the near-field FSI solver by feeding into the latter large-scale waves via the pressure-forcing method of Guo et al. (JCP 2009), appropriately adapted herein for the level set method. We validate the model under both simple wave trains and three-dimensional directional waves and compare the results with experimental and theoretical solutions. Finally, we demonstrate the capabilities of the new solver by carrying out large eddy simulation of a floating offshore wind turbine platform interacting with realistic ocean waves. This work is supported by the US Department of Energy (DE-EE0005482), the National Science Foundation (CBET-1341062), the University of Minnesota Initiative for Renewable Energy and the Environment, and the Minnesota Supercomputing Institute.

  7. Floating Life

    Institute of Scientific and Technical Information of China (English)

    YIN PUMIN

    2010-01-01

    @@ One in six people in China have left their hometown in search of a better life and the number continues to grow,creating a challenge for host cities,according to a government report.The floating population,or people who live and work outside their permanent home,reached 211 million last year and the number could reach 350 million by 2050 if govemment policies remain unchanged,said the Report on the Development of China's Floating Population issued on June 26 by the National Population and Family Planning Commission (NPFPC).

  8. Topographical effects on wave exciting forces on huge floating structure. 2; Ogata futaishiki kaiyo kozobutsu ni sayosuru haryoku ni kansuru kenkyu. 2

    Energy Technology Data Exchange (ETDEWEB)

    Imai, Y. [Hiroshima University, Hiroshima (Japan); Okusu, M. [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

    1996-12-31

    A method to predict drift force acting on a floating structure has been developed for a marine structure consisting of a number of floating elements, positioned in a region having a slope at the sea bottom. When a huge marine structure, such as floating air port, is located in a coastal area, scale of the overall structure is very large, of the order of scale of water depth change. The new method assumes that a marine structure consisting of an infinite number of cylindrical floating elements is installed in parallel to the seashore, where symmetrical nature of the configuration allows to predict behavior of the whole system by analyzing one element. Integration of pressures acting on structure surfaces determines the horizontal component of the drift force acting on the structure. Being influenced by topography, drift force predicted peaks at a frequency different from that for the level predicted on the assumption of constant water depth. This indicates the necessity for consideration of seabottom slope and effects of broken waves at the seashore. 6 refs., 12 figs.

  9. The floating water bridge

    International Nuclear Information System (INIS)

    When high voltage is applied to distilled water filled in two glass beakers which are in contact, a stable water connection forms spontaneously, giving the impression of a floating water bridge. A detailed experimental analysis reveals static and dynamic structures as well as heat and mass transfer through this bridge

  10. Compound floating pivot micromechanisms

    Science.gov (United States)

    Garcia, Ernest J.

    2001-04-24

    A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use compound floating pivot structures to attain far greater tilt angles than are practical using other micromechanical techniques. The new mechanisms are also capable of bi-directional tilt about multiple axes.

  11. On the sea-covering effect of a huge floating structure on the surrounding water; Choogata futai shuhen no kaisui ni taisuru kaimen shahei no eikyo ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Fujino, M.; Kagemoto, H.; Hamada, T. [The University of Tokyo, Tokyo (Japan)

    1996-12-31

    The numerical analysis program based on the difference method for dynamics of sea water with sea-surface displacement, flow rate, salt content and temperature as the parameters is modified to more accurately assess the effects of a huge marine structure on surrounding environment by adding the effects of insolation and boundary conditions of the sea-covering effects of the floating structure. The numerical simulation was done for summer and winter seasons, not in a sea area but using a rectangular bay with the floating structure at the center. A new flow evolves around the floating structure, due to the sea-covering effect. The flow patterns in summer and winter are clearly different, due to difference in insolation. The predicted flow is also sensitive whether stratification is considered or not, by which is meant that it is important what stratification effect is taken into account. Daily insolation changes are accompanied by vertical distribution of water temperature and its temporal change. These effects are also observed under the floating structure which shields insolation. 10 refs., 17 figs., 4 tabs.

  12. Floating radioluminography

    International Nuclear Information System (INIS)

    A new technique of phosphor screen imaging has been proposed. The floating radioluminography can be approached by exposing the imaging plate (IP) without bringing into contact with a radioactive sample. Thus, since it can be free from the radioactive contamination, we can employ the 3H-IP repeatedly. Moreover, when the exposure to the IP is held in a vacuum, the detection sensitivity can be greatly enhanced. (author)

  13. Slim-structured electro-floating display system based on the polarization-controlled optical path.

    Science.gov (United States)

    Kim, Seung-Cheol; Park, Seong-Jin; Kim, Eun-Soo

    2016-04-18

    A new slim-type electro-floating display system based on the polarization-controlled optical path is proposed. In the proposed system, the optical path between the input plane and Fresnel lens can be made recursive by repetitive transmission and reflection of the input beam by employing a new polarization-based optical path controller (P-OPC), which is composed of two quaterwave plates, a half mirror and a reflective polarizer. Based on this P-OPC, the absolute optical path between the input plane and Fresnel lens, virtually representing the physical depth of the display system, can be reduced down to one third of its original path, which results in the same rate of decrease in the volume size of the display system. The operational principle of the proposed system is analyzed with the Jones matrix. In addition, to confirm the feasibility of the proposed system, experiments with test prototypes are carried out, and the results are comparatively discussed with those of the conventional system. PMID:27137306

  14. Effect analysis of Reliability, Availability, Maintainability and Safety (RAMS ) Parameters in design and operation of Dynamic Positioning (DP) systems in floating offshore structures

    OpenAIRE

    Ebrahimi, Ali

    2010-01-01

    The objective of this thesis is to identify, which hazards and failures in operation process will affect Reliability, Availability, Maintainability and Safety of floating offshore structures. The focus is on Dynamic Positioning (DP) system that has the responsibility of keeping the offshore structure in the upright position operation. DP system is one of the most critical subsystems on these types of structures in terms of safety of operation and failure risk costs. Reliability of the system ...

  15. Basic investigation on deflection wave propagation and strength of very large floating structures; Choogata futai kozo no tawami hado denpa kyodo to kyodo ni kansuru kisoteki kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Tsubogo, T.; Okada, H. [University of Osaka Prefecture, Osaka (Japan). Faculty of Engineering

    1997-08-01

    The response strength in which deflection waves propagating in the elastic body of a large floating structure with an order of km in length and width was investigated. Attention was paid to the waves propagating the place fully away from the boundary of a very large floating body so as to obtain the dispersion relation of waves and the relation between incident waves and deflection waves. Next, the frequency response was checked from the aspect of the displacement amplitude and strength for beams and plates. The dispersion relation of waves propagating the place fully away from the boundary of a very large floating body and the relation between the waves and infinite-point incident waves were represented by an expression. Similarly, the waves propagates more than the infinite-point incident waves in frequency, wavelength, and speed. A lower-limit value exists in the propagation speed. The displacement and stress amplitudes are represented by a relational expression. For plates, the displacement amplitude increases when the wave direction coincides with the small-rigidity direction. The stress amplitude is maximized when the waves corresponding to the ``wave below a floating body = size of a characteristic wave number`` reach the large-rigidity direction. 10 refs., 10 figs., 2 tabs.

  16. Floating shoulder

    Directory of Open Access Journals (Sweden)

    B. de Pablo Márquez

    2014-09-01

    Full Text Available La fractura concomitante de clavícula y escápula es una entidad poco frecuente que puede ser una de las causas de afectación del complejo suspensorio del hombro también denominado hombro flotante (floating shoulder. Se relaciona frecuentemente con traumatismos de alta energía. Presentamos un caso de esta patología en un paciente varón de 28 años que consultó por caída en bicicleta con contusión sobre hombro izquierdo. Se describen las diferentes opciones terapéuticas planteadas, las imágenes radiológicas y una revisión de la literatura.

  17. Asynchronous Hybrid Kogge-Stone Structure Carry Select Adder Based IEEE-754 Double-Precision Floating-Point Adder

    Directory of Open Access Journals (Sweden)

    Abhijith Kini G.

    2011-09-01

    Full Text Available In this paper, the design and implementation of a generic fast asynchronous Hybrid Kogge-Stone Structure Carry Select based Adder (HKSS-CSA is described in detail and its application in the design of asynchronous Double Precision Floating-Point Adder (DPFPA is presented and the improved latency performance it provides is discussed. A detailed analysis in terms of maximum combinational delay, number of logic levels and logic resources used by both these adders is provided. The proposed HKSS-CSA adders performance is compared with a generic reference Carry Look-Ahead Adder (CLA in terms of the above parameters. For the same set of inputs, the HKSS-CSA resulted in approximately 40% (32-bit - 65% (128-bit reduction in the number of logic levels, thereby improving the overall latency by a factor of 2 (32-bit - 6 (128-bit times compared to a CLA. A 64-bit instance of this HKSS-CSA was made use of in the design of an asynchronous DPFPA and its performance compared with a reference DPFPA which makes use of a CLA in the intermediate stage. The reference DPFPA had a maximum combinational delay of 36.25ns while the newly suggested DPFPA had a delay of 18.60ns for the same set of inputs, giving about 50% improvement in overall latency performance, which can be mainly attributed to the latency improvement provided by the HKSS-CSA.

  18. Investigation of charge trapping mechanism for nanocrystal-based organic nonvolatile floating gate memory devices by band structure analysis

    Science.gov (United States)

    Lee, Dong-Hoon; Lim, Ki-Tae; Park, Eung-Kyu; Shin, Ha-Chul; Kim, Chung Soo; Park, Kee-Chan; Ahn, Joung-Real; Bang, Jin Ho; Kim, Yong-Sang

    2016-05-01

    This paper investigates the charge trapping mechanism and electrical performance of CdSe nanocrystals, such as nanoparticles and nanowires in organic floating gate memory devices. Despite of same chemical component, each nanocrystals show different electrical performances with distinct trapping mechanism. CdSe nanoparticles trap holes in the memory device; on the contrary, nanowires trap electrons. This phenomenon is mainly due to the difference of energy band structures between nanoparticles and nanowires, measured by the ultraviolet photoelectron spectroscopy. Also, we investigated the memory performance with C- V characteristics, charging and discharging phenomena, and retention time. The nanoparticle based hole trapping memory device has large memory window while the nanowire based electron trapping memory shows a narrow memory window. In spite of narrow memory window, the nanowire based memory device shows better retention performance of about 55% of the charge even after 104 sec of charging. The contrasting performance of nanoparticle and nanowire is attributed to the difference in their energy band and the morphology of thin layer in the device. [Figure not available: see fulltext.

  19. High pressure floating zone growth and structural properties of ferrimagnetic quantum paraelectric BaFe12O19

    Directory of Open Access Journals (Sweden)

    H. B. Cao

    2015-06-01

    Full Text Available High quality single crystals of BaFe12O19 were grown using the floating zone technique in 100 atm of flowing oxygen. Single crystal neutron diffraction was used to determine the nuclear and magnetic structures of BaFe12O19 at 4 K and 295 K. At both temperatures, there exist local electric dipoles formed by the off-mirror-plane displacements of magnetic Fe3+ ions at the bipyramidal sites. The displacement at 4 K is about half of that at room temperature. The temperature dependence of the specific heat shows no anomaly associated with long range polar ordering in the temperature range from 1.90 to 300 K. The inverse dielectric permittivity, 1/ε, along the c-axis shows a T2 temperature dependence between 10 K and 20 K, with a significantly reduced temperature dependence displayed below 10 K. Moreover, as the sample is cooled below 1.4 K there is an anomalous sharp upturn in 1/ε. These features resemble those of classic quantum paraelectrics such as SrTiO3. The presence of the upturn in 1/ε indicates that BaFe12O19 is a critical quantum paraelectric system with Fe3+ ions involved in both magnetic and electric dipole formation.

  20. DESIGN AND ANALYSIS OF TENSION LEG ANCHOR SYSTEMS FOR FLOATING WINDMILLS

    OpenAIRE

    Sachithanathamoorthy, Kumaravalavan

    2012-01-01

    Increasing demand for clean and effective energy production turns interests of the world on floating offshore wind technology. To establish floating wind farms, a wind turbine have to be mound on a floating structure. The floating structure has to be carefully design according to sea environmental condition and kept in precise position. Different types of floating structure and stationkeeping systems have been proposed for floating wind turbines. This project deals with design a spar floater...

  1. Consideration on the dynamic behavior and the structural design of large scale floating structure. 2nd Report. Stability of elastic structure and design of elastic response; Choogata futai no kozo kyodo oyobi kozo sekkei ni kansuru kosatsu. 2. Dansei henkei wo koryoshita fukugensei oyobi kozo oto no sekkei

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, H.; Yoshida, K. [The University of Tokyo, Tokyo (Japan)

    1996-12-31

    A policy of improving a very large floating body was planned based on its dynamic characteristics, and a proposal was made thereon. Furthermore, discussions were given on stability that considers effect of elastic deformation required when a structure is mounted on a floating body. With respect to a structural design of a very large floating body in which elastic response is governing, and upon modeling the very large floating body into an aeolotropic plate on an elastic supporting floor, it was shown that the existing range of natural vibration speed in the elastic response is in higher range than the natural vibration speed of heave. It was also indicated that the peak height of response to waves in resonance is inversely proportional to wave frequency, and furthermore, degree of flowing in of vibration energy during the resonance is determined by an inner product of spatial vibration patterns of wave force and the excited mode shape. A proposal was made on a floating body improved of excessive response in the floating body edges by changing the characteristics of the floating body edges. In addition, discussions were given on stability that considers elastic deformation of a floating body that becomes necessary when a structure, such as a building, is built on a very large floating body. 9 refs., 9 figs., 3 tabs.

  2. Compositional and structural changes at the anodic surface of thermally poled soda-lime float glass

    International Nuclear Information System (INIS)

    Applying high dc electric fields at elevated temperatures on silicate glasses results in displacement of ions, causing compositional and structural changes in the anodic surface. In this work, the ionic displacement was accompanied by electric current measurements during poling. The thickness of the Na+ depletion layer calculated from the current curves agrees with the thickness measured by EDS only if displacement of Ca2+ and O- are also taken into account. A depletion of Ca2+ in the anodic surface has in fact been observed. Structural changes were confirmed by infrared diffuse and specular reflectance spectroscopies. A narrowing of the band at about 1070 cm-1 can be attributed to an increase in the structural ordering degree. Refractive index measurements confirm compositional changes and contact angle measurements indicate the existence of a negative charge density at the anodic surface

  3. APPLICATION OF A NEURAL NETWORK PREDICTOR/CONTROLLER TO DYNAMIC POSITIONING OF FLOATING STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    An on-line training functional-link neural network predictor/controller for dynamic positioning of water surface structures is described in this paper. The on-line training neural network predictor acquires the knowledge about the system using a small number of samples of the latest system status measured on board of the structure. The trained function-link neural network is used with an optimal controller to control the output of the system. The accuracy and robustness of the on-line training predictor are demonstrated through the numerical simulations of two ship maneuvers. The on-line training neural network predictor/controller is applied to the dynamic positioning (station-keeping) of a ship in a uniform current with and without external environmental disturbances. The results of the numerical simulations are very satisfactory.

  4. A novel control algorithm for interaction between surface waves and a permeable floating structure

    Science.gov (United States)

    Tsai, Pei-Wei; Alsaedi, A.; Hayat, T.; Chen, Cheng-Wu

    2016-04-01

    An analytical solution is undertaken to describe the wave-induced flow field and the surge motion of a permeable platform structure with fuzzy controllers in an oceanic environment. In the design procedure of the controller, a parallel distributed compensation (PDC) scheme is utilized to construct a global fuzzy logic controller by blending all local state feedback controllers. A stability analysis is carried out for a real structure system by using Lyapunov method. The corresponding boundary value problems are then incorporated into scattering and radiation problems. They are analytically solved, based on separation of variables, to obtain series solutions in terms of the harmonic incident wave motion and surge motion. The dependence of the wave-induced flow field and its resonant frequency on wave characteristics and structure properties including platform width, thickness and mass has been thus drawn with a parametric approach. From which mathematical models are applied for the wave-induced displacement of the surge motion. A nonlinearly inverted pendulum system is employed to demonstrate that the controller tuned by swarm intelligence method can not only stabilize the nonlinear system, but has the robustness against external disturbance.

  5. A Novel Control Algorithm for Interaction Between Surface Waves and A Permeable Floating Structure

    Institute of Scientific and Technical Information of China (English)

    Pei-Wei TSAI; A ALSAEDI; T HAYAT; Cheng-Wu CHENe

    2016-01-01

    An analytical solution is undertaken to describe the wave-induced flow field and the surge motion of a permeable platform structure with fuzzy controllers in an oceanic environment. In the design procedure of the controller, a parallel distributed compensation (PDC) scheme is utilized to construct a global fuzzy logic controller by blending all local state feedback controllers. A stability analysis is carried out for a real structure system by using Lyapunov method. The corresponding boundary value problems are then incorporated into scattering and radiation problems. They are analytically solved, based on separation of variables, to obtain series solutions in terms of the harmonic incident wave motion and surge motion. The dependence of the wave-induced flow field and its resonant frequency on wave characteristics and structure properties including platform width, thickness and mass has been thus drawn with a parametric approach. From which mathematical models are applied for the wave-induced displacement of the surge motion. A nonlinearly inverted pendulum system is employed to demonstrate that the controller tuned by swarm intelligence method can not only stabilize the nonlinear system, but has the robustness against external disturbance.

  6. Polarization of Bi2Te3 thin film in a floating-gate capacitor structure

    International Nuclear Information System (INIS)

    Metal-Oxide-Semiconductor (MOS) capacitors with Bi2Te3 thin film sandwiched and embedded inside the oxide layer have been fabricated and studied. The capacitors exhibit ferroelectric-like hysteresis which is a result of the robust, reversible polarization of the Bi2Te3 thin film while the gate voltage sweeps. The temperature-dependent capacitance measurement indicates that the activation energy is about 0.33 eV for separating the electron and hole pairs in the bulk of Bi2Te3, and driving them to either the top or bottom surface of the thin film. Because of the fast polarization speed, potentially excellent endurance, and the complementary metal–oxide–semiconductor compatibility, the Bi2Te3 embedded MOS structures are very interesting for memory application

  7. Numerical response analysis of a large mat-type floating structure in regular waves; Matogata choogata futai kozobutsu no haro oto kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Yasuzawa, Y.; Kagawa, K.; Kitabayashi, K. [Kyushu University, Fukuoka (Japan); Kawano, D. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

    1997-08-01

    The theory and formulation for the numerical response analysis of a large floating structure in regular waves were given. This paper also reports the comparison between the experiment in the Shipping Research Institute in the Minitry of Transport and the result calculated using numerical analytic codes in this study. The effect of the bending rigidity of a floating structure and the wave direction on the dynamic response of a structure was examined by numerical calculation. When the ratio of structure length and incident wavelength (L/{lambda}) is lower, the response amplitude on the transmission side becomes higher in a wave-based response. The hydrodynamic elasticity exerts a dominant influence when L/{lambda} becomes higher. For incident oblique waves, the maximum response does not necessarily appear on the incidence side. Moreover, the response distribution is also complicated. For example, the portion where any flexible amplitude hardly appears exists. A long structure response can be predicted from a short structure response to some degree. They differ in response properties when the ridigity based on the similarity rule largely differs, irrespective of the same L/{lambda}. For higher L/{lambda}, the wave response can be easily predicted when the diffrection force is replaced by the concentrated exciting force on the incidence side. 13 refs., 14 figs., 3 tabs.

  8. Comparison of the community structures of ammonia-oxidizing bacteria and archaea in rhizoplanes of floating aquatic macrophytes.

    Science.gov (United States)

    Wei, Bo; Yu, Xin; Zhang, Shuting; Gu, Li

    2011-09-20

    Some common floating aquatic macrophytes could remove nutrients, such as nitrogen, from eutrophic water. However, the relationship between these macrophytes and the ammonia-oxidizing microorganisms on their rhizoplanes is still unknown. In this study, we examined communities of ammonia-oxidizing archaea (AOA) and bacteria (AOB) on the rhizoplanes of common floating aquatic macrophytes (Eichhornia crassipes, Pistia stratiotes and Ipomoea aquatic) in a eutrophic reservoir.The results show that AOB were the predominant ammonia-oxidizer on the three rhizoplanes. The principal AOB were Nitrosomonas europaea and Nitrosomonas ureae clades. The principal group of AOA was most similar to the clone from activated sludge. The ratio of AOB amoA gene copies to AOA varied from 1.36 (on E. crassipes) to 41.90 (on P. stratiotes). Diversity of AOA was much lower than that of AOB in most samples, with the exception of P. stratiotes. PMID:21239153

  9. Experimental study on the response of very large floating structures (VLFS) in wave; Choogata futaishiki kaiyo kozobutsu no harochu oto ni kansuru jikkenteki kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Ota, M.; Ikegami, H.; Yamaguchi, Y. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

    1997-10-01

    The elastic response of VLFS of 1200m long in wave was studied experimentally using a water tank and integral elastic model of 1/80 scale. As offshore airport, a ultra- thin box type floating structure of 5km long, 1km wide and several meter thick is used, and the effect of elasticity is not negligible for such a structure. The experiment used a water tank of 160m long, 30m wide and 3.1m deep. Supposing a water depth of 20m for real VLFSs, the experiment was carried out mainly in a local shallow water area prepared with a temporary bottom together with that in a deep water area. A simple mooring equipment with a linear spring equivalent to real VLFSs was used. The integral floating model was prepared by not mechanical but welded junction to obtain uniform elasticity. The response in wave showed a complicated 3-D behavior, offering useful data for verification of a behavior estimation method. The response was nearly equal between shallow and deep water areas at the same wave length, and the response amplitude in regular waves was equivalent to the significant amplitude in long and short crested irregular waves. 7 refs., 8 figs., 3 tabs.

  10. Secretory vesicles in live cells are not free-floating but tethered to filamentous structures: A study using photonic force microscopy

    International Nuclear Information System (INIS)

    It is well established that actin and microtubule cytoskeletal systems are involved in organelle transport and membrane trafficking in cells. This is also true for the transport of secretory vesicles in neuroendocrine cells and neurons. It was however unclear whether secretory vesicles remain free-floating, only to associate with such cytoskeletal systems when needing transport. This hypothesis was tested using live pancreatic acinar cells in physiological buffer solutions, using the photonic force microscope (PFM). When membrane-bound secretory vesicles (0.2-1.2 μm in diameter) in live pancreatic acinar cells were trapped at the laser focus of the PFM and pulled, they were all found tethered to filamentous structures. Mild exposure of cells to nocodazole and cytochalasin B, disrupts the tether. Immunoblot analysis of isolated secretory vesicles, further demonstrated the association of actin, myosin V, and kinesin. These studies demonstrate for the first time that secretory vesicles in live pancreatic acinar cells are tethered and not free-floating, suggesting that following vesicle biogenesis, they are placed on their own railroad track, ready to be transported to their final destination within the cell when required. This makes sense, since precision and regulation are the hallmarks of all cellular process, and therefore would hold true for the transport and localization of subcellular organelles such as secretory vesicles

  11. "Floating shoulder" injuries.

    Science.gov (United States)

    Heng, Kenneth

    2016-12-01

    "Floating shoulder" is a rare injury complex resulting from high-energy blunt force trauma to the shoulder, resulting in scapulothoracic dissociation. It is commonly associated with catastrophic neurovascular injury. Two cases of motorcyclists with floating shoulder injuries are described. PMID:26961729

  12. Floating VAWT Concepts

    OpenAIRE

    Schmidt Paulsen, Uwe; Friis Pedersen, Troels; Vita, Luca

    2008-01-01

    The report contains a wrap-up of existing knowledge and conceptual review on VAWTs for offshore applications. Key topics in floating VAWT design such as foundations, integration of floating foundations with VAWT rotor, design developments and conceptual modifications from onshore applications are processed. A new design concept is described.

  13. Floating wind turbine system

    Science.gov (United States)

    Viterna, Larry A. (Inventor)

    2009-01-01

    A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

  14. Optimal Selection of Floating Platform for Tidal Current Power Station

    OpenAIRE

    Fengmei Jing; Gang Xiao; Nasir Mehmood; Liang Zhang

    2013-01-01

    With continuous development of marine engineering, more and more new structures are used in the exploring of tidal current energy. Three are there different kinds of support structures for tidal current power station, which are sea-bed mounted/gravity based system, pile mounted system and floating moored platform. Comparison with them, the floating mooring system is suit for deep water and the application of which will be widely. In this study, catamaran and semi-submersible as floating platf...

  15. FLOAT Project - Task 1

    DEFF Research Database (Denmark)

    Marchalot, Tanguy; Kofoed, Jens Peter; Sørensen, Eigil V.;

    The objective of the FLOAT project is to study the reliability of high-performance fibre-reinforced concrete, also known as Compact Reinforced Composite (CRC), for the floats of wave energy converters. In order to reach commercial breakthrough, wave energy converters need to achieve a lower price...... (dexawave.com, 2011). CRC floats could be a very cost-effective technology with enhanced loading capacity and environmental resistance, and very low maintenance requirements, affecting directly the final energy price. The project involves DEXA Wave Energy Ltd, Wave Star A/S, Aalborg University and Hi-Con A...

  16. Structure Fatigue Analysis of Floating Tidal Power Station Carrier%漂浮式潮流电站载体结构疲劳分析

    Institute of Scientific and Technical Information of China (English)

    徐国明; 孙苏龙; 刘峰

    2015-01-01

    漂浮式潮流电站载体在波浪交变载荷的长期作用下容易产生疲劳破坏,进而带来整体结构的安全隐患,因此在设计初期需进行节点疲劳分析,预测结构工作寿命,并对易疲劳部位结构采取措施以延长使用周期。本文基于谱分析法,应用短期疲劳累积损伤理论和S-N曲线,通过计算两个节点在不同工况与波浪频率组合下的热点应力范围,结合功率谱密度函数,分析了某200kW漂浮式潮流电站在特定海域下的疲劳特性,结果表明疲劳寿命满足使用年限要求。%The floating tidal power station carrier is subject to fatigue failure due to the long-term effect of alternating wave load, and is furthermore subject to the risks of structural safety. Therefore it is essential, at the early stage of design, to do the node fatigue analysis, to predict the working life of the structure and to take measures on the structure of the easy-fatigue parts for longer working period. Based on the spectral analysis method, applying the short-term fatigue cumulative damage theory and the S-N curve, the paper analyzes the fatigue performance for a 200kW floating tidal power station carrier under particular sea condition, by calculating the hot spot stress range of two nodes under the combination of different conditions and wave frequencies, as well as combining the power spectral density function. The results show that the fatigue life meets the requirement of the service life.

  17. Man made floating island

    Energy Technology Data Exchange (ETDEWEB)

    Martinak, B.

    1987-08-04

    An artificial island is described for use in energy production from ocean waves, comprising: a platform disposed atop the ocean surface; vertically disposed rigid posts extending beneath the platform short of the ocean floor; a stationary wave amplifier affixed to the posts, the wave amplifier of a conical shape with inclined sides for directing water upwardly from substantially any lateral direction when submerged to amplify wave action; a movable inverted conical float slidably mounted for translation movement along the posts and disposed between the platform and the wave amplifier for movement with the waves; an apex of the conical float directed substantially toward an apex of the conical wave amplifier; and an energy-drive device disposed on the platform. A means is provided for converting the motion of the float to transmittable energy for operating the energy-driven device.

  18. Floating family holds future promise

    International Nuclear Information System (INIS)

    The growth plans of a company aimed at the market for floating oil production platforms are described following recent acquisitions. Topics covered include floating production systems, advanced technology products and services to the offshore industry. (UK)

  19. Tethered float liquid level sensor

    Energy Technology Data Exchange (ETDEWEB)

    Daily, III, William Dean

    2016-09-06

    An apparatus for sensing the level of a liquid includes a float, a tether attached to the float, a pulley attached to the tether, a rotation sensor connected to the pulley that senses vertical movement of said float and senses the level of the liquid.

  20. Hydroelastic responses of pontoon type very large floating offshore structures. 2nd Report. Effect of the water depth and the drift forces; Pontoon gata choogata futaishiki kaiyo kozobutsu no harochu chosei oto ni kansuru kenkyu. 2. Senkai eikyo to hyoryuryoku

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, H.; Miyajima, S. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science; Masuda, K.; Ikoma, T. [Nihon University, Tokyo (Japan). College of Science and Technology

    1996-12-31

    Steady-state drift force in regular waves is theoretically analyzed. It is also studied under combined external force experimentally using a two-dimensional water tank. The fluid forces are analyzed by the pressure distribution method based on the potential theory, in which the effects of water depth are taken into account to discuss the effects of elastic deformation of the floating structure on the drift characteristics of steady-state waves. The tests were carried out using a wave-making circulating water tank equipped with a wind duct to create wind, waves and tidal flow. Drift force under a combined external force by wind, wave and/or tidal flow cannot be accurately predicted by arithmetically adding these components. For predicting drift force by tidal flow, it is necessary to take into account drag force in current at the floating structure bottom as well as that in wind at the front face. Drift force by tidal flow is affected by shallowness of water, which should be taken into account for drag forces. The floating structure will be deformed along the wave face as its stiffness decreases, basically decreasing steady-state drift force. 9 refs., 14 figs.

  1. Private Floating World.

    OpenAIRE

    Clay, Allyson

    1998-01-01

    The tondi in the series "Private Floating World" show three views of a particular location in Disneyland. Rather, they show the same view with the only difference being distance from the image. Paradoxically, nothing more is revealed in the image offering the closest view. 

  2. Reliability Analysis and Safety Factor Value of Anti-floating of Structure%构筑物抗浮可靠度分析及抗浮安全系数取值

    Institute of Scientific and Technical Information of China (English)

    崇峻; 卢红前

    2012-01-01

    依据工程结构可靠性设计理论,对构筑物的抗浮可靠度进行了分析,并将结果换算成相应的抗浮安全系数.研究表明:采用单一安全系数法难以准确反映构筑物抗浮稳定性的实际状态;对只受重力荷载和浮托力作用的构筑物,采用可靠度分析方法可以较为准确地反应构筑物抗浮稳定性的实际状况.当上浮效应为浮力时,无论是正常使用阶段,还是临时工况,应取抗浮稳定安全系数Kf≥1.10;对开槽埋设的钢筋混凝土沉管隧道,建议取Kf≥1.20.%Based on the theory of engineering structural reliability design, the reliability index is obtained and converted into safety factor aiming at anti-floating of structure. The results showed that "the method of single safe factor" is not good enough in anti-floating stability assessment. The structure bearing gravity loads and uplift force, the reliability method could precisely reflect actual state of anti-floating stability. If buoyancy is chosen as uprising effect, the corresponding anti-floating stability is not less than 1. 10 or 1. 20 (used in trench-buried reinforced concrete immersed tunnel) during construction and operation.

  3. Mooring system design for floating wind turbines

    OpenAIRE

    Laks, Annika

    2014-01-01

    Recently, there has been a lot of research on floating wind turbines. These structures have to be moored for a station keeping, which is relatively straightforward for deep waters. In transitional water depths (35-70 m) however, it is not obvious how to find a good, cost-efficient mooring system.In this thesis a catenary mooring system for a typical floating wind turbine is designed with different options for the cables: chains, metal and synthetic rope, mixed type and clump weights. The anal...

  4. Floating liquid bridge charge dynamics

    Science.gov (United States)

    Teschke, Omar; Soares, David Mendez; Gomes, Whyllerson Evaristo; Valente Filho, Juracyr Ferraz

    2016-01-01

    The interaction of liquid with electric fields is investigated in a configuration where up to 13 kV are applied between electrodes resulting in a 106 V/m electric field in the capillaries and where there is the formation of a free-standing fluid bridge in the interelectrode gap. The Mott-Gurney equation was fitted to the measured ionization current vs applied voltage curve which indicates that the ionization rate at the high-voltage anode electrode dimethylsulfoxide (DMSO) interface and space charging in the interelectrode gap determine the floating liquid bridge current for a given cathode-to-anode voltage. Space charge effects were measured in the cathode becker and also at the liquid bridge since the ionized charges at the anode migrate to the bridge outer surface and decrease the interfacial tension from 43 mJ/m2 to 29 mJ/m2. Two distinct structural regions then form the bridge, a charged plastic (bulk modulus ˜100 MPa) conducting outer layer with a surface conductivity of ˜10-9 Ω-1, which shapes and supports the floating fluid structure, and an inner liquid cylinder, where DMSO molecules flow.

  5. Polarization of Bi{sub 2}Te{sub 3} thin film in a floating-gate capacitor structure

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Hui, E-mail: hyuan@gmu.edu, E-mail: qli6@gmu.edu; Li, Haitao; Zhu, Hao [Department of Electrical and Computer Engineering, George Mason University, Fairfax, Virginia 22030 (United States); Semiconductor and Dimensional Metrology Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8120 (United States); Zhang, Kai; Baumgart, Helmut [Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia 23529 (United States); Bonevich, John E. [Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Richter, Curt A. [Semiconductor and Dimensional Metrology Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8120 (United States); Li, Qiliang, E-mail: hyuan@gmu.edu, E-mail: qli6@gmu.edu [Department of Electrical and Computer Engineering, George Mason University, Fairfax, Virginia 22030 (United States)

    2014-12-08

    Metal-Oxide-Semiconductor (MOS) capacitors with Bi{sub 2}Te{sub 3} thin film sandwiched and embedded inside the oxide layer have been fabricated and studied. The capacitors exhibit ferroelectric-like hysteresis which is a result of the robust, reversible polarization of the Bi{sub 2}Te{sub 3} thin film while the gate voltage sweeps. The temperature-dependent capacitance measurement indicates that the activation energy is about 0.33 eV for separating the electron and hole pairs in the bulk of Bi{sub 2}Te{sub 3}, and driving them to either the top or bottom surface of the thin film. Because of the fast polarization speed, potentially excellent endurance, and the complementary metal–oxide–semiconductor compatibility, the Bi{sub 2}Te{sub 3} embedded MOS structures are very interesting for memory application.

  6. Structure analysis and magnetic properties of nano-sized lithium-copper ferrite particles classified by using ultrasonic floating-sedimentation method.

    Science.gov (United States)

    Choi, Yong; Lee, Sang Heon

    2013-09-01

    Ultrasonic floating-sedimentation (UFS) method was applied to classify nano-sized lithium-copper ferrite particles with about 30 nm in size. The nano-sized ferrite particles were prepared by self-propagating high temperature synthesis (SHS) reaction with different initial composition ratio of lithium peroxide to copper oxide followed by mechanical milling, which combustion temperature and combustion rate at 1.0 MP of oxygen pressure were in the ranges of 870 degrees C to 930 degrees C and 4.2 to 5.5 mm sec(-1), respectively. Neutron diffraction analysis revealed that the final products of the SHS reaction with initial molar ratios of lithium peroxide to copper oxide of 0.5 and 1.0 were mainly Li0.29Cuo.61Fe,2O4 and Li0.42Cu0.58Fe2O4 with Fd3m structure, which lattice parameters were 0.8340 nm and 0.8332 nm, respectively. As the molar ratio of lithium peroxide to copper oxide increased from 0.5 to 1.0, the maximum magnetization (Ms), residual magnetization (Mr) and coercive force (iHc) were increased about 35%, 18% and 17%, respectively, which were related to non-stoichiometry of the ferrites. Complex permeability of the ferrite-rubber composites specimen decreased with the increase of frequency with peak real value of at about 0.8 GHz, and their dielectric constant were epsilon'r = 10.9 and epsilon'r" = 0.2, respectively. PMID:24205595

  7. Reliability of floating foundation concepts for vertical axis wind turbines

    OpenAIRE

    Athanasios J. Kolios; Collu, Maurizio; Brennan, Feargal P.

    2010-01-01

    Offshore wind turbines are developing at a rapid pace. By far the most common turbine configuration is the HAWT (Horizontal Axis Wind Turbine) and development of these machines is largely centered about drive train and blade issues with some work concerning foundations/ supporting structures. Several teams around the world are developing floating supporting structures for HAWT, mainly for deep water deployment. This paper describes the development of a floating support structure for Vertical ...

  8. Effect of a floating electrode on a plasma jet

    International Nuclear Information System (INIS)

    Two kinds of floating electrode, floating dielectric barrier covered electrode (FDBCE) and floating pin electrode (FPE), which can enhance the performance of plasma jet are reported. The intense discharge between the floating electrode and power electrode decreased the voltage to trigger the plasma jet substantially. The transition of plasma bullet from ring shape to disk shape in the high helium concentration region happened when the floating electrode was totally inside the powered ring electrode. The enhanced electric field between propagating plasma bullet and ground electrode is the reason for this transition. The double plasma bullets happened when part of the FDBCE was outside the powered ring electrode, which is attributed to the structure and surface charge of FDBCE. As part of the FPE was outside the powered ring electrode, the return stroke resulted in a single intensified plasma channel between FPE and ground electrode

  9. 钢弹簧浮置板轨道结构顶升前后减振效果分析%Damping effect analysis on damping effect of steel spring floating slab track structure before and after jacking

    Institute of Scientific and Technical Information of China (English)

    张建鹏

    2012-01-01

    This paper made live test and analysis on damping effect of steel spring floating slab track structure before and after jacking, for the first time made time domain and frequency domain analysis on tunnel wall and ground vibration of steel spring floating slab track section in the construction phase when through the track flat car, elaborated the damping effect of floating plate and the vibration influence level of metro, and proposed the new solutions of nuisance problems in metro construction process.%对钢弹簧浮置板轨道结构在顶升前后的减振效果进行了实测分析,首次对处于施工阶段的钢弹簧浮置板地段通过轨道平板车时的隧道壁及地面振动进行了时域及频域分析,阐述了地铁对地面的振动影响水平及浮置板的减振效果,提出了地铁线路施工过程中扰民问题的新解决方案。

  10. Unification of box shapes in molecular simulations

    NARCIS (Netherlands)

    Bekker, H.

    1997-01-01

    In molecular simulations with periodic boundary conditions the computational box may have five different shapes: triclinic; the hexagonal prism; two types of dodecahedrons; and the truncated octahedron. In this article, we show that every molecular simulation, formulated in one of these boxes, can b

  11. Hydroelastic analysis of a very large floating plate with large deflections in stochastic seaway

    DEFF Research Database (Denmark)

    Chen, Xu-jun; Jensen, Jørgen Juncher; Cui, Wei-cheng;

    2004-01-01

    The hydroelasticity of a very large floating plate with large deflections in multidirectional irregular waves is discussed. After a brief introduction on wave loads on a flexible structure, the paper derives the generalised fluid force acting on a floating structure in multidirectional irregular...... value statistics. A very large floating structure is chosen as an example. The numerical results show that the membrane forces have an influence on the vertical displacements and the bending moments....

  12. Floating offshore turbines

    DEFF Research Database (Denmark)

    Tande, John Olav Giæver; Merz, Karl; Schmidt Paulsen, Uwe;

    2014-01-01

    modifications, but on a spar and a semi-submersible floater, respectively. Other concepts suggest new types of turbines, e.g., the DeepWind concept consisting of a vertical axis turbine and a subsea generator. The three concepts represent different approaches: HyWind and WindFloat are already in a demonstration...... reductions, and series production for installation of wind farms. DeepWind is in an early phase and not proven, but with promising perspectives. © 2014 John Wiley & Sons, Ltd....

  13. Floating nuclear power plants

    International Nuclear Information System (INIS)

    This article examines the legal regime for floating nuclear power plants (FNPs), in view of the absence of specific US legislation and the very limited references to artificial islands in the Law of the Sea Convention. The environmental impacts of FNPs are examined and changes in US regulation following the Three Mile Island accident and recent US court decisions are described. References in the Law of the Sea Convention relevant to FNPs are outlined and the current status of international law on the subject is analysed. (author)

  14. Floating boom assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, J.D.

    1994-08-03

    A floating boom has associated means for injecting one or more flows of fluid (gas and/or liquid) adjacent an external surface of the boom. Such a flow may be arranged to rise up the side of the boom, staying close to it owing to the Coanda effect. This may serve to discourage a lighter liquid (e.g. oil) on the surface of the bulk liquid from passing under the boom and/or assist passage of the lighter liquid over a weir into a reservoir (which may be provided within the boom). (Author)

  15. Hydraulics of multi-chamber type floating breakwater

    International Nuclear Information System (INIS)

    Floating type breakwater has the advantage of mobility, so that it is useful for the temporal structure to keep water basen calm during the harbor construction works. A floating type breakwater, named ''multi-chamber type floating breakwater'', which is composed of a multiple-chamber with open area at both top and bottom is developed in this paper. This paper discusses the characteristics of this breakwater such as wave sheltering effect, mooring methods and acting tension on mooring ropes based on the results of the hydraulic model experiments. (author)

  16. Floating microspheres: a review

    Directory of Open Access Journals (Sweden)

    Jagtap Yogesh Mukund

    2012-03-01

    Full Text Available Gastric emptying is a complex process, one that is highly variable and that makes in vivo performance of drug delivery systems uncertain. A controlled drug delivery system with prolonged residence time in the stomach can be of great practical importance for drugs with an absorption window in the upper small intestine. The main limitations are attributed to the inter- and intra-subject variability of gastro-intestinal (GI transit time and to the non-uniformity of drug absorption throughout the alimentary canal. Floating or hydrodynamically controlled drug delivery systems are useful in such applications. Various gastroretentive dosage forms are available, including tablets, capsules, pills, laminated films, floating microspheres, granules and powders. Floating microspheres have been gaining attention due to the uniform distribution of these multiple-unit dosage forms in the stomach, which results in more reproducible drug absorption and reduced risk of local irritation. Such systems have more advantages over the single-unit dosage forms. The present review briefly addresses the physiology of the gastric emptying process with respect to floating drug delivery systems. The purpose of this review is to bring together the recent literature with respect to the method of preparation, and various parameters affecting the performance and characterization of floating microspheres.O esvaziamento gástrico é um processo complexo, com elevada variabilidade e responsável pela incerteza do desempenho dos medicamentos in vivo. Dessa forma, os sistemas de liberação modificada de fármacos, com tempo de residência prolongado no estômago, em especial, considerando aqueles fármacos com janela de absorção na porção superior do intestino delgado, apresentam fundamental importância. As principais limitações relativas à absorção do fármaco são, no geral, atribuídas à variabilidade inter e intra-paciente do tempo de trânsito gastro-intestinal (GI e

  17. Floating shoulder” injuries

    OpenAIRE

    Heng, Kenneth

    2016-01-01

    Floating shoulder” is a rare injury complex resulting from high-energy blunt force trauma to the shoulder, resulting in scapulothoracic dissociation. It is commonly associated with catastrophic neurovascular injury. Two cases of motorcyclists with floating shoulder injuries are described.

  18. WindWaveFloat (WWF): Final Scientific Report

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Alla; Roddier, Dominique; Banister, Kevin

    2012-03-30

    Principle Power Inc. and National Renewable Energy Lab (NREL) have completed a contract to assess the technical and economic feasibility of integrating wave energy converters into the WindFloat, resulting in a new concept called the WindWaveFloat (WWF). The concentration of several devices on one platform could offer a potential for both economic and operational advantages. Wind and wave energy converters can share the electrical cable and power transfer equipment to transport the electricity to shore. Access to multiple generation devices could be simplified, resulting in cost saving at the operational level. Overall capital costs may also be reduced, provided that the design of the foundation can be adapted to multiple devices with minimum modifications. Finally, the WindWaveFloat confers the ability to increase energy production from individual floating support structures, potentially leading to a reduction in levelized energy costs, an increase in the overall capacity factor, and greater stability of the electrical power delivered to the grid. The research conducted under this grant investigated the integration of several wave energy device types into the WindFloat platform. Several of the resulting system designs demonstrated technical feasibility, but the size and design constraints of the wave energy converters (technical and economic) make the WindWaveFloat concept economically unfeasible at this time. Not enough additional generation could be produced to make the additional expense associated with wave energy conversion integration into the WindFloat worthwhile.

  19. Frequency-domain modelling of floating wind turbines

    OpenAIRE

    Lupton, Richard

    2015-01-01

    The development of new types of offshore wind turbine on floating platforms requires the development of new approaches to modelling the combined platform-turbine system. In this thesis a linearised frequency-domain approach is developed which gives fast but approximate results: linearised models of the structural dynamics, hydrodynamics, aerodynamics and control system dynamics are brought together to find the overall response of the floating wind turbine to harmonic wind...

  20. Synthesis, structural characterization and evaluation of floating B-N codoped TiO2/expanded perlite composites with enhanced visible light photoactivity

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • We added expanded perlite as a floating carrier to immobilize B-N codoped TiO2. • The photo-reaction occurred on the surface of water and easily utilized the solar energy and O2 to make photodegradation efficiently. • The composites combined the adsorptivity of expanded perlite and photoactivity of B-N-TiO2. • The floating photocatalysts give a simple way to recycle, which is important to the application of photocatalysis technology. - Abstract: Floating photocatalysts of boron-nitrogen codoped TiO2 grafted on expanded perlite (B-N-TiO2/EP) were prepared by a facile sol–gel method. The catalysts were characterized by N2 adsorption–desorption (BET), scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectroscopy (UV–vis–DRS). The results revealed that the physicochemical properties of the photocatalysts, such as BET surface area, porosity and pore size could be controlled by adjusting the calcination temperature and EP dosage. XRD patterns were mainly influenced by calcination temperature and the transformation of anatase to rutile occurred at 650 °C. Uniform TiO2 loading, higher surface area and absorption in visible light region were obtained for B-N-TiO2/EP calcined at 550 °C with 3.0 g EP addition. Moreover, photocatalytic activity for RhB destruction under visible light irradiation was slightly influenced by TiO2 loading in the range of 1–3 g EP dosage. BNTEP550 showed the highest photocatalytic activity indicating to be a promising photocatalyst employed to remediate contaminated waters using solar irradiation

  1. Synthesis, structural characterization and evaluation of floating B-N codoped TiO{sub 2}/expanded perlite composites with enhanced visible light photoactivity

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xin; Wang, Wei; Wang, Xuejiang, E-mail: wangxj@tongji.edu.cn; Zhang, Jing; Zhao, Jianfu; Gu, Zaoli; Zhou, Lijie

    2015-09-15

    Graphical abstract: - Highlights: • We added expanded perlite as a floating carrier to immobilize B-N codoped TiO{sub 2}. • The photo-reaction occurred on the surface of water and easily utilized the solar energy and O{sub 2} to make photodegradation efficiently. • The composites combined the adsorptivity of expanded perlite and photoactivity of B-N-TiO{sub 2}. • The floating photocatalysts give a simple way to recycle, which is important to the application of photocatalysis technology. - Abstract: Floating photocatalysts of boron-nitrogen codoped TiO{sub 2} grafted on expanded perlite (B-N-TiO{sub 2}/EP) were prepared by a facile sol–gel method. The catalysts were characterized by N{sub 2} adsorption–desorption (BET), scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectroscopy (UV–vis–DRS). The results revealed that the physicochemical properties of the photocatalysts, such as BET surface area, porosity and pore size could be controlled by adjusting the calcination temperature and EP dosage. XRD patterns were mainly influenced by calcination temperature and the transformation of anatase to rutile occurred at 650 °C. Uniform TiO{sub 2} loading, higher surface area and absorption in visible light region were obtained for B-N-TiO{sub 2}/EP calcined at 550 °C with 3.0 g EP addition. Moreover, photocatalytic activity for RhB destruction under visible light irradiation was slightly influenced by TiO{sub 2} loading in the range of 1–3 g EP dosage. BNTEP550 showed the highest photocatalytic activity indicating to be a promising photocatalyst employed to remediate contaminated waters using solar irradiation.

  2. Investigation on the dynamic response and strength of very long floating structures by beam modeling on an elastic foundation; Dansei shishojo no hari model ni yoru chodai futai kozo no doteki tawami kyodo tokusei ni kansuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Tsubogo, T.; Okada, H. [University of Osaka Prefecture, Osaka (Japan). Faculty of Engineering

    1997-08-01

    A very large floating structure was replaced with the beam on an elastic foundation to examine the response characteristics in waves. Another evidence was regularly and numerically given for the basic characteristics of a very large floating body Suzuki found. New information was also obtained. The frequency response is mainly classified into a wave number control area and proper frequency control area when buoyancy elasticity exists. When the buoyancy structure is long and flexible, the proper frequency becomes continuous and the frequency control area becomes a resonance area. In the wave number control area, the Suzuki`s characteristic wave number becomes a control parameter, and various characteristic values are indicated by characteristic wave numbers. The response in the wave number control area becomes quasi-static when the distribution mass of buoyancy is fully small. The design in which the distribution mass of buoyancy is fully large must be avoided. In the displacement amplitude, the mass on the free end is severest. The proper frequency of vertical vibration relatively moves to the high-frequency side when buoyancy is considered as an elastic foundation. Attention must be thus paid to the proper frequency of vibration on the horizontal surface. 9 refs., 12 figs., 3 tabs.

  3. Impact on floating membranes

    CERN Document Server

    Vandenberghe, Nicolas

    2016-01-01

    When impacted by a rigid object, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. In the first place, a longitudinal wave front -- associated with in-plane deformation of the membrane and traveling at constant speed -- separates an outward stress free domain with a stretched but flat domain. Then, in the stretched domain a dispersive transverse wave travels at a wave speed that depends on the local stretching rate. We study the dynamics of this fluid-body system and we show that the wave dynamics is similar to the capillary waves that propagate at a liquid-gas interface but with a surface tension coefficient that depends on impact speed. We emphasize the role of the stretching in the membrane in the wave dynamics but also in the development of a buckling instability that give rise to radial wrinkles.

  4. Floating Silicon Method

    Energy Technology Data Exchange (ETDEWEB)

    Kellerman, Peter

    2013-12-21

    The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.

  5. Simulation of suppression of floating-body effect in partially depleted SOI MOSFET using a Si1-x Ge x dual source structure

    International Nuclear Information System (INIS)

    The effect of the Si1-x Ge x source with an underlying p+ region on the suppression of the floating body effects in a partially depleted silicon-on-insulator (SOI) metal oxide silicon field effect transistor (MOSFET) is numerically investigated. Compared to a conventional SOI MOSFET, the kink effect and anomalous sub-threshold slope are reduced and the breakdown voltage is substantially increased. The detailed suppression mechanism is also studied. Our results suggest that the narrow bandgap Si1-x Ge x source and buried p+ region are favorable to the dispersion of holes generated by impact ionization

  6. Floating into Deep Space

    Science.gov (United States)

    La Frenais, R.; Saraceno, T.; Powell, J.

    2014-04-01

    Is it possible for spaceflight to become more sustainable? Artist and architect Tomas Saraceno proposes a long-term artscience research project based on his initial work with solar balloons to join with the efforts of engineers such as John Powell, working on the Airship to Orbit experiments, which describe a three stage process of using airships to fly to a large suborbital "Dark Sky Station' then literally floating into orbit with additional electrical and chemical propulsion. (See: http://www.jpaerospace.com) In his artworks Tomás Saraceno proposes cell-like flying cities as possible architectonic living spaces in direct reference to Buckminster Fuller's Cloud Nine (circa 1960). The fantastic architectural utopia Cloud Nine consists of a freely floating sphere measuring one mile in diameter that offers living space to several autonomous communities encompassing thousands of inhabitants each. The notion of the cloud is essential to the artist's work. The cloud as metaphor stands for artistic intention, for the meaning of territory and border in today's (urban) society, and for exploring possibilities for the sustainable development of the human living environment. In Saraceno's work this environment is not limited to the earth, but is explicitly conceived to reach into outer space. (Biomimetic Constructions- On the works of Tomás Saraceno By Katharina Schlüter) Saraceno is also interested in human factors experiments using his existing constructions as analogue environments for living on Mars and is proposing carry out a series of workshops, experiments and solar balloon launces in White Sands desert in early 2016 in collaboration with the curator Dr Rob La Frenais, the Rubin Center at The University of Texas at El Paso and various scientific partners.

  7. Migration Laws of Floating Population in Mianyang

    Institute of Scientific and Technical Information of China (English)

    LiuPeng

    2005-01-01

    Based on the overall anatysis of the floating population among big and medium-sized cities in China, this paper, by means of statistics and questionnaires, makes a systematical study on the migratory features of the floating population in Mianyang, its employment structure, migrating causes and channels, According to the findings, the author finds a fact that with the strategy of Western Development, and with the construction of science and technology city of Mianyang, the migrating in Mianyang conforms to the general patterns of themigration, which has happened in those big and medium-sized cities in China. In addition, the city has a new but unique feature - economic factor, as the driving force of popufation migration, is quite distinct from that of those cities in eastern areas of China.

  8. Control development for floating wind

    International Nuclear Information System (INIS)

    Control of a floating wind turbine has proven to be challenging, but essential for lowering the cost of floating wind energy. Topic of a recent joint R and D project by GustoMSC, MARIN and ECN, is the concept design and verification with coupled simulations and model tests of the GustoMSC Tri-Floater. Only using an integral design approach, including mooring and control design, a cost effective system can be obtained. In this project, ECN developed a general floating wind turbine control strategy and applied this in a case study to the GustoMSC Tri-Floater and the OC3Hywind spar, both equipped with the NREL 5MW RWT. The designed controller ensures stable operation, while maintaining proper speed and power regulation. The motions of the floating support are reduced and substantial load reduction has been achieved

  9. Control development for floating wind

    Science.gov (United States)

    Savenije, Feike; Peeringa, Johan

    2014-06-01

    Control of a floating wind turbine has proven to be challenging, but essential for lowering the cost of floating wind energy. Topic of a recent joint R&D project by GustoMSC, MARIN and ECN, is the concept design and verification with coupled simulations and model tests of the GustoMSC Tri-Floater. Only using an integral design approach, including mooring and control design, a cost effective system can be obtained. In this project, ECN developed a general floating wind turbine control strategy and applied this in a case study to the GustoMSC Tri-Floater and the OC3Hywind spar, both equipped with the NREL 5MW RWT. The designed controller ensures stable operation, while maintaining proper speed and power regulation. The motions of the floating support are reduced and substantial load reduction has been achieved.

  10. Novel Floating General Element Simulators Using CBTA

    OpenAIRE

    U. E. Ayten; Sagbas, M.; Herencsar, N.; J. Koton

    2012-01-01

    In this study, a novel floating frequency dependent negative resistor (FDNR), floating inductor, floating capacitor and floating resistor simulator circuit employing two CBTAs and three passive components is proposed. The presented circuit can realize floating FDNR, inductor, capacitor or resistor depending on the passive component selection. Since the passive elements are all grounded, this circuit is suitable for fully integrated circuit design. The circuit does not require any component ma...

  11. Electrically floating, near vertical incidence, skywave antenna

    Science.gov (United States)

    Anderson, Allen A.; Kaser, Timothy G.; Tremblay, Paul A.; Mays, Belva L.

    2014-07-08

    An Electrically Floating, Near Vertical Incidence, Skywave (NVIS) Antenna comprising an antenna element, a floating ground element, and a grounding element. At least part of said floating ground element is positioned between said antenna element and said grounding element. The antenna is separated from the floating ground element and the grounding element by one or more electrical insulators. The floating ground element is separated from said antenna and said grounding element by one or more electrical insulators.

  12. Impact on floating membranes

    Science.gov (United States)

    Vandenberghe, Nicolas; Duchemin, Laurent

    2016-05-01

    When impacted by a rigid body, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. First, a longitudinal wave front, associated with in-plane deformation of the membrane and traveling at constant speed, separates an outward stress-free domain from a stretched domain. Then, in the stretched domain a dispersive transverse wave travels at a speed that depends on the local stretching rate. The dynamics is found to be self-similar in time. Using this property, we show that the wave dynamics is similar to the capillary waves that propagate at a liquid-gas interface but with a surface tension coefficient that depends on impact speed. During wave propagation, we observe the development of a buckling instability that gives rise to radial wrinkles. We address the dynamics of this fluid-body system, including the rapid deceleration of an impactor of finite mass, an issue that may have applications in the domain of absorption of impact energy.

  13. Spoke Dimension on the Motion Performance of a Floating Wind Turbine with Tension-Leg Platform

    OpenAIRE

    Wang, H. F.; Fan, Y. H.

    2016-01-01

    The tension-leg platform (TLP) supporting structure is a good choice for floating offshore wind turbines because TLP has superior motion dynamics. This study investigates the effects of TLP spoke dimensions on the motion of a floating offshore wind turbine system (FOWT). Spoke dimension and offshore floating TLP were subjected to irregular wave and wind excitation to evaluate the motion of the FOWT. This research has been divided into two parts: (1) Five models were designed based on differen...

  14. Turbomachinery systems for floating production applications

    Energy Technology Data Exchange (ETDEWEB)

    Windt, Jonathan P.; Kurz, Rainer [Solar Turbines Incorporated, San Diego, CA (United States)

    2008-07-01

    Since 1995 there has been a dramatic increase in oil and gas exploration and production using floating platforms in deeper waters located further offshore. This exploration started with tension leg platforms, progressed through SPARs and Semi-Submersibles, and later evolved into Floating Production Storage and Offloading (FPSO) vessels. Turbomachinery equipment installed on a floating platform or vessel will be expected to operate in the same manner as a land based machine, but in a variety of climate and environmental conditions that now includes motion. To operate successfully, specific design considerations for the turbo-machinery packages are required. It is critical to take into account the type of vessel, the expected list, trim and dynamic motion angles, the dynamic forces applied, the expected deck deflection as a result of those forces, understand the applicable class requirement, and where the equipment will be located on the vessel. This information is then translated into the design conditions to determine the type of mounting method to be used to attach the turbo-machinery package to the deck, the expected accelerations for structural analysis, and oil tank and system designs for fluid management. Furthermore, compressor designs need to allow utmost flexibility to adapt to changing operating conditions. (author)

  15. Development and Evaluation of Gastro-Retentive Floating Acyclovir Tablets

    Directory of Open Access Journals (Sweden)

    Girani S

    2015-12-01

    Full Text Available In the present study an attempt was made to prepare acyclovir floating tablets. Acyclovir floating tablets (200mg were prepared by direct compression method using HPMC, sodium carboxy methyl cellulose and carbopol with an effervescent base (sod. Bicarbonate and citric acid. FTIR study confirmed the absence of any drug/polymer/excipients interactions. The prepared floating tablets were evaluated for hardness, weight variation, thickness, friability, drug content uniformity, buoyancy lag time, total floating time, swelling index and in vitro dissolution studies. Among all the 12 formulations F1, F2, F3, F4, F5, F6, F10, F11, F12 showed good floating property while formulations F7, F8, F9 showed moderate floating while all the 12 formulations showed controlled drug release. Stability studies were carried out for F4 and F10, both the formulations showed good stability. It was observed that F4 and F10 gave maximum drug release upto 97.17% within 24 hrs.SEM study indicates that both the tablets F4 &F10 have smooth and uniform surface before the dissolution study, but after the dissolution study, the Tablet F4 which was prepared withsod.CMC has shown erosion of the polymer matrix. But the Tablet F10 have shown spongy like structure, the matrix was swollen and pores were created.

  16. Floating Cities, Islands and States

    CERN Document Server

    Bolonkin, Alexander

    2008-01-01

    Many small countries are in need of additional territory. They build landfills and expensive artificial islands. The ocean covers 71 per cent of the Earth surface. Those countries (or persons of wealth) starting the early colonization of the ocean may obtain advantages through additional territory or creating their own independent state. An old idea is building a big ship. The best solution to this problem, however, is the provision of floating cities, islands, and states. The author idea is to use for floating cities, islands, and states a cheap floating platform created from a natural ice field taken from the Arctic or Antarctic oceans. These cheap platforms protected by air-film (bottom and sides) and a conventional insulating cover (top) and having a cooling system can exist for an unlimited time. They can be increased in number or size at any time, float in warm oceans, travel to different continents and countries, serve as artificial airports, harbors and other marine improvements, as well as floating c...

  17. Artisanal fishing net float loss and a proposal for a float design solution

    Directory of Open Access Journals (Sweden)

    Paulo de Tarso Chaves

    2016-03-01

    Full Text Available Abstract Plastic floats from fishing nets are commonly found washed up on beaches in southern Brazil. They are usually broken and show signs of having been repaired. Characteristics of floats and interviews with fishermen suggest two main causes of float loss. First, collisions between active gear, bottom trawl nets for shrimp, and passive gear, drift nets for fish, destroy nets and release fragments of them, including floats. Second, the difficulty with which floats are inserted on the float rope of the nets when they are used near the surface. Floats are inserted to replace damaged or lost floats, or they may be removed if it is desired that the nets be used in deeper waters. Floats may thus be poorly fixed to the cables and lost. Here a new float design that offers greater safety in use and for the replacement of floats is described and tested.

  18. Optimal Selection of Floating Platform for Tidal Current Power Station

    Directory of Open Access Journals (Sweden)

    Fengmei Jing

    2013-06-01

    Full Text Available With continuous development of marine engineering, more and more new structures are used in the exploring of tidal current energy. Three are there different kinds of support structures for tidal current power station, which are sea-bed mounted/gravity based system, pile mounted system and floating moored platform. Comparison with them, the floating mooring system is suit for deep water and the application of which will be widely. In this study, catamaran and semi-submersible as floating platform of tidal current power station are studied. And they are compared with its economic, efficiency of turbine and stability of station. It is found that the catamaran is optimal choice. Based on basic ship theory and using software MOSES, the stability of Catamaran tidal current power station is also calculated. The research of this study is significant and it will be as the reference for the future study.

  19. Low Noise Bias Current/Voltage References Based on Floating-Gate MOS Transistors

    DEFF Research Database (Denmark)

    Igor, Mucha

    1997-01-01

    The exploitation of floating-gate MOS transistors as reference current and voltage sources is investigated. Test structures of common source and common drain floating-gate devices have been implemented in a commercially available 0.8 micron double-poly CMOS process. The measurements performed...

  20. Wave attenuation charcteristics of tethered float system

    Digital Repository Service at National Institute of Oceanography (India)

    Vethamony, P.

    and transmitted wave powers, transmission coefficients are computed. The results show that transmission coefficient does not vary with changes in wave height or water depth. When depth of submergence of float increases, wave attenuation decreases, showing... incident wave height transmitted wave height G wave number float mass number of rows of floats drag power transmitted wave power incident wave power 111 112 P. Vethamony float radius wave period time velocity and acceleration of fluid...

  1. Designing seaplane hulls and floats

    Science.gov (United States)

    Benoit,

    1926-01-01

    Experimental data, such as the results of tank tests of models, render it possible to predict, at least in principle, as to how a hull or float of a given shape will comport itself. We will see further along, however, how uncertain these methods are and how they leave room for empiricism, which will reign for a long time yet in seaplane research bureaus.

  2. Feasibility design of a floating airport and estimation of environmental forces on it; Futaishiki kuko no sekkei to kankyo gairyoku no suitei ni kansuru kento

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Y.; Tabeta, S.; Takei, Y. [Yokohama National University, Yokohama (Japan). Faculty of Engineering

    1996-12-31

    A rough design was performed on a floating airport. On this floating structure, environmental external force was estimated, mooring design was carried out, and discussions was given on the position retaining performance important for airport functions and behavior of the floating structure. The discussion was given on cases that the airport is surrounded and not surrounded by floating breakwaters. A floating structure which becomes super-large in size requires considerations on force due to sea level gradient as a result of a tide. Deriving flow condition changes and force acting on the floating structure simultaneously by using numerical calculations makes it possible to estimate current force given with considerations on influence of the flow conditions created by installing the floating airport. Estimation was carried out by using a zone dividing method on wave drifting force acting upon the floating airport. As a result, it was found that installing floating and permeating type breakwaters can reduce the wave drifting force acting on the floating airport. The wave drifting force working on the floating airport can be reduced by installing the floating and permeating type breakwaters to lower levels than when no such breakwaters are installed. The airport may be moored with less number of fenders when the fenders of the same type are used. 18 refs., 10 figs., 5 tabs.

  3. The Research of Road Traffic Based on Floating Car Data

    Science.gov (United States)

    Zhang, Junyou; Jian, Meng; Tang, Rui

    Based on the analysis of floating car traffic information acquisition and processing system structure and construction frame, combining the Zibo floating car features and road conditions, using historical data provided by Zibo city bus companies, adopting the ArcGIS Engine of ESRI company as a map components, putting forward the nearest point estimate map matching algorithms, combining data fusion technology based on Kalman filter and road running speed calibration algorithm, predicting road traffic running status in certain period and express it in the GIS map, this paper completed the design, the practice has proved the suggested method is feasible.

  4. Optimal Control of a Ballast-Stabilized Floating Wind Turbine

    DEFF Research Database (Denmark)

    Christiansen, Søren; Knudsen, Torben; Bak, Thomas

    2011-01-01

    structural stiffness of a floating installation in combination with a coupling between the fore–aft motion of the tower and the blade pitch. To address this problem, the present paper models a ballast-stabilized floating wind turbine, and suggests a linear quadratic regulator (LQR) in combination with a wind...... estimator and a state observer. The results are simulated using aero elastic code and analysed in terms of damage equivalent loads. When compared to a baseline controller, this controller clearly demonstrates better generator speed and power tracking while reducing fatigue loads....

  5. Feasibility study on floating nuclear power station

    International Nuclear Information System (INIS)

    It is stipulated that nuclear power plants are to be built on solid rock bases on land in Japan. However, there are a limited number of appropriate siting grounds. The Central Research Institute of Electric Power Industry has engaged since 1981 in the studies on the construction technology of power plants, aiming at establishing new siting technology to expand the possible siting areas for nuclear power plants. Underground siting is regarded as a proven technology due to the experience in underground hydroelectric power plants. The technology of siting on quaternary ground is now at the stage of verification. In this report, the outline of floating type offshore/inshore siting technology is introduced, which is considered to be feasible in view of the technical and economical aspects. Three fixed structure types were selected, of which the foundations are fixed to seabed, plant superstructures are above sea surface, and which are floating type. Aiming at ensuring the aseismatic stability of the plant foundations, the construction technology is studied, and the structural concept omitting buoyancy is possible. The most practical water depth is not more than 20 m. The overall plant design, earthquake isolation effect and breakwater are described. (Kako, I.)

  6. Exponential flux-controlled memristor model and its floating emulator

    Institute of Scientific and Technical Information of China (English)

    刘威; 王发强; 马西奎

    2015-01-01

    As commercial memristors are still unavailable in the market, mathematic models and emulators which can imitate the features of the memristor are meaningful for further research. In this paper, based on the analyses of characteristics of the q–ϕ curve, an exponential flux-controlled model, which has the quality that its memductance (memristance) will keep monotonically increasing or decreasing unless the voltage’s polarity reverses (if not approach the boundaries), is constructed. A new approach to designing the floating emulator of the memristor is also proposed. This floating structure can flexibly meet various demands for the current through the memristor (especially the demand for a larger current). The simulations and experiments are presented to confirm the effectiveness of this model and its floating emulator.

  7. Organic nano-floating-gate transistor memory with metal nanoparticles

    Science.gov (United States)

    Van Tho, Luu; Baeg, Kang-Jun; Noh, Yong-Young

    2016-04-01

    Organic non-volatile memory is advanced topics for various soft electronics applications as lightweight, low-cost, flexible, and printable solid-state data storage media. As a key building block, organic field-effect transistors (OFETs) with a nano-floating gate are widely used and promising structures to store digital information stably in a memory cell. Different types of nano-floating-gates and their various synthesis methods have been developed and applied to fabricate nanoparticle-based non-volatile memory devices. In this review, recent advances in the classes of nano-floating-gate OFET memory devices using metal nanoparticles as charge-trapping sites are briefly reviewed. Details of device fabrication, characterization, and operation mechanisms are reported based on recent research activities reported in the literature.

  8. Airship-floated wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Watson, W. K.

    1985-01-01

    A wind turbine, by use of a tethered airship for support, may be designed for the economical recovery of power at heights of 2,000 feet or more above ground, at which height power density in the wind is typically three times the power density available to a conventionally supported wind turbine. Means can be added to such an airship-floated wind turbine which will permit its generators to be used to meet load demand even during periods of little or no wind. Described to this end is a wind turbine system which combines, among other novel features: a novel tether line system which provides access for men and materials to the supporting airship while in active service, a novel system for providing additional buoyant lift at the nose of the turbine-supporting airship to offset the vertical component of tension induced in the tether line by the downwind force exerted by the turbine blades, a novel bearing assembly at the nose of the supporting airship which permits the airship to rotate as a unit with the turbine it supports without causing a similar rotation of the tether line, a novel turbine airship structure which handles concentrated loads from the turbine efficiently and also permits the safe use of hydrogen for buoyancy, a novel ''space frame'' structure which supports the turbine blades and greatly reduces blade weight, a novel system for controlling turbine blade angle of incidence and for varying blade incidene in synchrony with blade angular position abut the turbine axis to provide greater control over airship movement, a novel system for locating propellor-driven generators out at the wind turbine perimeter and for using lightweight, high-RPM generators to produce electrical energy at a power line frequency, which greatly reduces the weight required to convert turbine blade torque into useful power, and a novel system for incorporating compressed air storage and combustion turbine components into the wind turbine's generator drive

  9. A Method for Modeling of Floating Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Wang, Kai; Hansen, Martin Otto Laver; Moan, Torgeir

    2013-01-01

    It is of interest to investigate the potential advantages of floating vertical axis wind turbine (FVAWT) due to its economical installation and maintenance. A novel 5MW vertical axis wind turbine concept with a Darrieus rotor mounted on a semi-submersible support structure is proposed in this paper...

  10. Comparative study of hydroelastic responses of semisubmersible type and pontoon type very large floating structure in waves; Tachushiki semisabugata to pontoon gata choogata futai no harochu dansei oto no hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Ma, N.; Hirayama, T.; Sato, N. [Yokohama National University, Yokohama (Japan). Faculty of Engineering

    1996-12-31

    A semisubmersible very large floating structure is compared with an equivalent pontoon type in vertical displacement and longitudinal bending moment in waves. The theoretical calculation is based on the mode synthesis method, and fluid force is analyzed by the three-dimensional singularity method for the symmetric structure, in which the effects of elastic deformation are taken into account. The semisubmersible and pontoon types are not much different from each other in eigenfrequency and mode shape in the dry mode. In the wet mode, on the other hand, the pontoon type is characterized by the synthetic mode in which torsional and bending modes overlap each other, each mode having a similar eigenfrequency. These types are different in elastic response, the pontoon type having several tens times higher coefficient of attenuation than the semisubmersible type. The pontoon type is generally lower in response, but its torsional mode is excited in transverse waves, making it higher than the semisubmersible type at near eigenfrequency of this mode. 15 refs., 17 figs., 2 tabs.

  11. Floating on the margins [Environmental issues for floating production platforms

    International Nuclear Information System (INIS)

    The main environmental issues challenging oilfield development using floating production platforms in harsh environments such as the Atlantic frontier are discussed. These fall into two broad categories -operating conditions and biological disturbance. Particular combinations of wind and currents can lead to extremely difficult operating conditions through which floating units are expected to maintain production for economic reasons. This imposes stringent conditions on the design and construction of tanker hulls and of risers to enable them to remain connected at all times. Prediction of wind and wave forces is a crucial element of operational and safety planning. Fauna in seabed sediments disturbed by pipeline laying often relocate but some seeding back of colonies may be required in hard rock areas. Migration routes for cetaceans and the feeding grounds of marine birds must be considered and the potential long and short term damage to commercial fisheries through discharges need to be assessed. A significant risk is the interaction of sub-sea facilities and fishing gear and oil spills. Operational and accidental discharges of production chemicals, produced water containing oil, deck drainage and treated sewage, and discharges to air from flaring and utility exhausts are of major environmental concern calling for mitigation and protection measures and contingency plans. Some of the environmental issues associated with decommissioning are reduced by the use of floating platforms but there are global and national regulations governing the process. (UK)

  12. Damping Wind and Wave Loads on a Floating Wind Turbine

    OpenAIRE

    Torben Knudsen; Søren Christiansen; Thomas Bak

    2013-01-01

    Offshore wind energy capitalizes on the higher and less turbulent wind speeds at sea. To enable deployment of wind turbines in deep-water locations, structures are being explored, where wind turbines are placed on a floating platform. This combined structure presents a new control problem, due to the partly unconstrained movement of the platform and ocean wave excitation. If this additional complexity is not dealt with properly, this may lead to a significant increase in the structural loads ...

  13. Surface passivation by a floating junction

    Energy Technology Data Exchange (ETDEWEB)

    Loelgen, P.; Leguijt, C. (FOM Institute for Atomic and Molecular Physics, Amsterdam (Netherlands)); Verhoef, L.A. (R+S Renewable Energy Systems, Helmond (Netherlands)); Sinke, W.C.; Eikelboom, J.A.; Steeman, R.A.; De Moor, H.H.C. (ECN Renewable Energy, Petten (Netherlands))

    1994-04-01

    Measurements of the effective surface recombination velocity S[sub eff] of a floating-emitter structure on low resistivity Si under low injection conditions are presented. The S[sub eff] of highly doped emitters on 3[Omega]cm Cz p-type Si is determined with photoconductivity decay probed by microwaves ([mu]-PCD) for different emitter thicknesses. With these unpassivated emitters S[sub e]ff values of 230 cm/s are obtained. Etching off most of the dead layer and applying surface passivation in the form of a Si-nitride layer results in an S[sub e]ff below 100 cm/s. The measured S[sub e]ff are in good agreement with the S[sub cal] calculated with the measured emitter doping profiles. 10x10 cm[sup 2] floating-emitter solar cells were processed on multicristalline Si and the S[sub e]ff was determined by photocurrent decay measurements (LBICD). 3 figs., 1 tab., 11 refs.

  14. Floating Point Engine using VHDL

    Directory of Open Access Journals (Sweden)

    Najib Ghatte

    2014-02-01

    Full Text Available Floating Point arithmetic is by far the most used way of approximating real number arithmetic for performing numerical calculations on modern computers. Each computer had a different arithmetic for long time: bases, significant and exponents’ sizes, formats, etc. Each company implemented its own model and it hindered the portability between different equipments until IEEE 754 standard appeared defining a single and universal standard. This paper deals with the implementation of single precision as well as double precision floating point arithmetic adder as well as multiplier according with the IEEE 754 standard and using the hardware programming language VHDL. VHDL Codes so designed are simulated for various set of inputs and desired results are obtained. Codes are synthesized on device XC3S5000 having package as FG900 of Spartan®-3 FPGA family.

  15. Floating Population Increase and Its Influence on the Urban Population Situation: A Case Study in Beijing

    Institute of Scientific and Technical Information of China (English)

    Wu Peilin; Lu Qi

    2005-01-01

    Floating population is a special population group in China resulting from the implementation of household registration system. This paper uses a set of floating population survey data, population censuses data and statistical data to analyze the increase and influence of floating population on the urban population situations in Beijing. It is found that Beijing has experienced a rapid increase of floating population since the 1990s and that the increase of this group has become the key factor of the current population expansion in the city. Its distribution in the urban regions intensified and extended the subutbanization process of the capital. In addition,the population structures of sex, age, education and employment in Beijing have changed to some extent due to the influx of floating population.

  16. Floating production systems: Selection and economics

    International Nuclear Information System (INIS)

    Floating and Production Systems (FPS) are gradually emerging from their basic application as a stop-gap method of offshore production, when all else has failed the economic go/no go threshold. Accordingly, the primary reason for FPS selection, for any offshore development, is that the FPS is cheaper than the fixed or compliant platform alternatives. How much cheaper it has to be, is not a simple comparison of structure and facility costs but a complex evaluation of well system interfaces, pipelines versus offshore storage, existing infrastructure and ultimately, corporate culture. The emergence of the FPS as a viable alternative to the large, fixed structure, is being forced on the offshore production industry because of these economic constraints. With the window of opportunity for FPS application, there is also a high degree of responsibility which must be undertaken by both the operator and contractor, in terms of FPS establishment

  17. Motion of floating wind turbines

    OpenAIRE

    Linde, Børge

    2010-01-01

    Motion of floating wind turbines has been studied. A literature study on different concepts and what tools are available for simulating them is presented. Marintek’s simulation software SIMO is used for time simulations. In the calculations, the hydrodynamic forces, mooring line forces and aerodynamic forces from the tower and rotor are taken into account. In addition a pitch control algorithm is used for the rotor blades. Results are compared to available experimental results from model test...

  18. Floating VAWT wind farm concepts

    OpenAIRE

    Schmidt Paulsen, Uwe; Friis Pedersen, Troels; Vita, Luca

    2008-01-01

    The report contains proposals and descriptions of VAWTs of 200kW, 1MW, 5MW and 25MW sizes in terms of dimensions, weights, loads, and power production. Additionally a proposal of the use of each of these sizes in a concept description for a 100MW wind farm. Manufacture, transportation, installation, maintenance and operation of VAWTs are considered briefly. A summary on advantages and disadvantages of floating VAWTs is given.

  19. Wind and Wave Disturbances Compensation to Floating Offshore Wind Turbine Using Improved Individual Pitch Control Based on Fuzzy Control Strategy

    OpenAIRE

    Feng Yang; Qing-wang Song; Lei Wang; Shan Zuo; Sheng-shan Li

    2014-01-01

    Due to the rich and high quality of offshore wind resources, floating offshore wind turbine (FOWT) arouses the attentions of many researchers. But on a floating platform, the wave and wind induced loads can significantly affect power regulation and vibration of the structure. Therefore, reducing these loads becomes a challenging part of the design of the floating system. To better alleviate these fatigue loads, a control system making compensations to these disturbances is proposed. In this p...

  20. Modeling and Parameter Analysis of the OC3-Hywind Floating Wind Turbine with a Tuned Mass Damper in Nacelle

    OpenAIRE

    Yulin Si; Hamid Reza Karimi; Huijun Gao

    2013-01-01

    Floating wind turbine will suffer from more fatigue and ultimate loads compared with fixed-bottom installation due to its floating foundation, while structural control offers a possible solution for direct load reduction. This paper deals with the modelling and parameter tuning of a spar-type floating wind turbine with a tuned mass damper (TMD) installed in nacelle. First of all, a mathematical model for the platform surge-heave-pitch motion and TMD-nacelle interaction is established based on...

  1. Challenges in Simulation of Aerodynamics, Hydrodynamics, and Mooring-Line Dynamics of Floating Offshore Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Matha, D.; Schlipf, M.; Cordle, A.; Pereira, R.; Jonkman, J.

    2011-10-01

    This paper presents the current major modeling challenges for floating offshore wind turbine design tools and describes aerodynamic and hydrodynamic effects due to rotor and platform motions and usage of non-slender support structures.

  2. Hydrodynamic coefficients of a simplified floating system of gravity cage in waves

    Institute of Scientific and Technical Information of China (English)

    Chang-wen WU; Fu-kun GUI; Yu-cheng LI; Wei-huan FANG

    2008-01-01

    Numerical simulation and experimental tests were carried out to examine the hydrodynamic behaviors of a double-column floating system of gravity cage under wave conditions. A floating system of gravity cage can be treated as a small-sized floating structure when compared with the wavelengths. The main problem in calculating the wave loads on the small-sized floating structure is to obtain the reasonable force coefficients, which may differ from a submerged structure. In this paper, the floating system of gravity cage is simplified to a 2D problem, where the floating system is set symmetrically under wave conditions. The motion equations were deduced under wave conditions and a specific method was proposed to resolve the problem of wave forces acting on a small-sized floating system of gravity cage at water surface. Results of the numerical method were compared with those from model tests and the hydrodynamic coefficients Cn and C?were studied. It is found that Cn ranges from 0.6 to 1.0 while C?is between 0.4 and 0.6 in this study. The results are useful for research on the hydrodynamic behavior of the deep-water gravity sea cages.

  3. 2-D numerical simulation for fully nonlinear wave interaction with floating structures%二维浮式结构物与完全非线性波相互作用数值分析

    Institute of Scientific and Technical Information of China (English)

    顾思琪; 朱仁庆; 吴梓鑫

    2015-01-01

    Taking continuity equation of incompressible fluid , N-S equation and structural dynamics equation as the governing equations and using fully nonlinear free surface conditions and structural boundary conditions , we establish the viscous numerical wave tank based on viscous flow theory , fluid-solid coupling theory and free surface tracking technique -VOF (Volume of Fluid) method.Wave running up along the bow , wave deforming and wave breaking are recorded in these simulations .The wave height on deck and motion response such as pitch, heave and sway are obtained .The results indicate that the present numerical scheme and method can be used to simulate the fully nonlinear wave interaction with the floating structures .%基于粘流理论、流固耦合理论和自由液面追踪技术———VOF(Volume of Fluid)法,以不可压缩流体的连续方程和N-S方程及结构动力学方程为基本控制方程,利用商用软件ANSYS Workbench 的二次开发功能,建立了粘性数值波浪水池,数值模拟了完全非线性波的生成,计算分析了二维浮式结构物遭遇波浪的完全非线性现象,得到了甲板上浪水位高度和结构物的纵摇、垂荡、横摇等运动响应。结果表明:文中的方法可以用于波浪与浮式结构物相互作用的完全非线性数值模拟。

  4. Wave Disturbance Reduction of a Floating Wind Turbine Using a Reference Model-based Predictive Control

    OpenAIRE

    Christiansen, Søren; Tabatabaeipour, Seyed Mojtaba; Bak, Thomas; Knudsen, Torben

    2013-01-01

    Floating wind turbines are considered as a new and promising solution for reaching higher wind resources beyond the water depth restriction of monopile wind turbines. But on a floating structure, the wave-induced loads significantly increase the oscillations of the structure. Furthermore, using a controller designed for an onshore wind turbine yields instability in the fore-aft rotation. In this paper, we propose a general framework, where a reference model models the desired closed-loop beha...

  5. PRELIMINARY ASSESSMENT of a SEMI-SUBMERSIBLE FLOATING WIND TURBINE COMBINED with PITCHING WAVE ENERGY CONVERTERS

    OpenAIRE

    Soulard, Thomas; Babarit, Aurélien; Borgarino, Bruno

    2013-01-01

    This paper synthesizes the technical feasibility study carried out for a hybrid ocean energy converter. The solution envisaged involves a 100m large semi-submersible platform designed with five columns and equipped with floating pitching Wave Energy Converters (WECs). This floating structure is mounted with a 5MW wind turbine. The present study covers power performance estimations and structural analysis. The first section describes the “Wave to Wire” model programmed in both frequency and ti...

  6. General Floating Element Simulator Employing VDCCs and Grounded Components

    OpenAIRE

    KARTCI, A.

    2015-01-01

    In this study, a new general floating element simulator circuit employing two voltage differencing current conveyors (VDCCs) and three passive components is proposed. Depending on the passive component selection the presented circuit can realize floating frequency dependent negative resistor (FDNR), floating inductor, floating capacitor, and floating resistor simulator circuits. The circuit does not require any component matching conditions. Moreover, the proposed FDNR, inductance, capacitor ...

  7. 14 CFR 27.753 - Main float design.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 27.753 Section 27.753... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 27.753 Main float design. (a) Bag floats. Each bag float must be designed to withstand— (1) The maximum pressure...

  8. 14 CFR 29.753 - Main float design.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 29.753 Section 29.753... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.753 Main float design. (a) Bag floats. Each bag float must be designed to withstand— (1) The maximum pressure...

  9. Future floating community for Singapore 2030

    OpenAIRE

    Mäkinen, Sami

    2015-01-01

    The subject of the thesis is “Future Floating Community for Singapore 2030”. As a starting point the thesis concentrates on creating one visionary floating community concept for Singapore 2030. Urban development in highly populated coastal cities, high land prices, dense infrastructure and global warming with raising sea level scenarios can put even more pressure towards floating community developments. This kind of situation and pressure can be noticed in Singapore where the sea level ha...

  10. Floating wind turbines : the transport phase

    OpenAIRE

    Solli, Knut Jostein

    2008-01-01

    The worldwide demand of renewable energy is increasing rapidly because of the climate problem. Wind energy appears as a clean and good solution to cope with a great part of this energy demand. Therefore, floating wind turbines have been investigated as a possible solution to increase the efficiency from the wind, as a renewable energy source. A critical phase for the floating wind turbines is the transport phase. Economically, the floating wind turbines should be transported in...

  11. Discrete Element Modelling of Floating Debris

    Science.gov (United States)

    Mahaffey, Samantha; Liang, Qiuhua; Parkin, Geoff; Large, Andy; Rouainia, Mohamed

    2016-04-01

    Flash flooding is characterised by high velocity flows which impact vulnerable catchments with little warning time and as such, result in complex flow dynamics which are difficult to replicate through modelling. The impacts of flash flooding can be made yet more severe by the transport of both natural and anthropogenic debris, ranging from tree trunks to vehicles, wheelie bins and even storage containers, the effects of which have been clearly evident during recent UK flooding. This cargo of debris can have wide reaching effects and result in actual flood impacts which diverge from those predicted. A build-up of debris may lead to partial channel blockage and potential flow rerouting through urban centres. Build-up at bridges and river structures also leads to increased hydraulic loading which may result in damage and possible structural failure. Predicting the impacts of debris transport; however, is difficult as conventional hydrodynamic modelling schemes do not intrinsically include floating debris within their calculations. Subsequently a new tool has been developed using an emerging approach, which incorporates debris transport through the coupling of two existing modelling techniques. A 1D hydrodynamic modelling scheme has here been coupled with a 2D discrete element scheme to form a new modelling tool which predicts the motion and flow-interaction of floating debris. Hydraulic forces arising from flow around the object are applied to instigate its motion. Likewise, an equivalent opposing force is applied to fluid cells, enabling backwater effects to be simulated. Shock capturing capabilities make the tool applicable to predicting the complex flow dynamics associated with flash flooding. The modelling scheme has been applied to experimental case studies where cylindrical wooden dowels are transported by a dam-break wave. These case studies enable validation of the tool's shock capturing capabilities and the coupling technique applied between the two numerical

  12. Breakdown voltage in vertical power FLIMOSFETs with one internal floating island

    Science.gov (United States)

    Galadi, A.; Morancho, F.; Hassani, M. M.

    2008-09-01

    Recently a new power FLIMOSFET ('floating islands MOSFET') structure was proposed to reduce conduction losses in power MOS devices. The vertical FLIMOSFET offers a better trade-off between breakdown voltage and specific on-resistance compared to the conventional VDMOSFET. The improvement of this trade-off was obtained by inserting one (or several) floating island(s) in the epitaxial layer of the VDMOS transistor. In this paper, theoretical analysis of breakdown voltage of the FLIMOSFET with a single floating island is proposed. This analytical method exhibits good agreement with 2D simulations and measurements.

  13. Breakdown voltage in vertical power FLIMOSFETs with one internal floating island

    International Nuclear Information System (INIS)

    Recently a new power FLIMOSFET ('floating islands MOSFET') structure was proposed to reduce conduction losses in power MOS devices. The vertical FLIMOSFET offers a better trade-off between breakdown voltage and specific on-resistance compared to the conventional VDMOSFET. The improvement of this trade-off was obtained by inserting one (or several) floating island(s) in the epitaxial layer of the VDMOS transistor. In this paper, theoretical analysis of breakdown voltage of the FLIMOSFET with a single floating island is proposed. This analytical method exhibits good agreement with 2D simulations and measurements

  14. 14 CFR 29.521 - Float landing conditions.

    Science.gov (United States)

    2010-01-01

    ... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Water Loads § 29.521 Float landing... among the floats; and (2) For each float, the load share determined under paragraph (b)(1) of...

  15. Nuclear floating power desalination complexes

    International Nuclear Information System (INIS)

    Russia is a single country in the world which possesses a powerful ice-breaker transport fleet that allows a solution of important social-economic tasks of the country's northern regions by maintaining a year-round navigation along the Arctic sea route. A total operating record of the marine nuclear reactors up until till now exceeds 150 reactor-years, with their main equipment operating life reacting 120 thousand hours. Design and constructional progresses have been made continuously during forty years of nuclear-powered ships construction in Russia. Well proven technology of all components experienced in the marine nuclear reactors give grounds to recommend marine NSSSs of KLT-40 type as energy sources for the heat and power co-generation plants and the sea water desalination complexes, particularly as a floating installation. Co-generation stations are considered for deployment in the extreme Northern Region of Russia. Nuclear floating desalination complexes can be used for drinkable water production in the coastal regions of Northern Africa, the Near East, India etc. (author)

  16. Block floating point for radar data

    DEFF Research Database (Denmark)

    Christensen, Erik Lintz

    1999-01-01

    Integer, floating point, and block floating point (BFP) data formats are analyzed and compared in order to establish the mathematical tools for selection of an optimal format which fulfils the demands of high resolution radar (SAR) data to large dynamic range and adequate S/N. The analysis takes...

  17. Floating Entanglement Witness Measure and Genetic Algorithm

    OpenAIRE

    Baghbanpourasl, A.; Najarbashi, G.; Seyedkazemi, M.

    2007-01-01

    In this paper based on the notion of entanglement witness, a new measure of entanglement called floating entanglement witness measure is introduced which satisfies some of the usual properties of a good entanglement measure. By exploiting genetic algorithm, we introduce a classical algorithm that computes floating entanglement witness measure. This algorithm also provides a method for finding entanglement witness for a given entangled state.

  18. Vertical pump with free floating check valve

    International Nuclear Information System (INIS)

    A vertical pump is described which has a bottom discharge with a free floating check valve disposed in the outlet plenum thereof. The free floating check valve comprises a spherical member with a hemispherical cage-like member attached thereto which is capable of allowing forward or reverse flow under appropriate conditions while preventing reverse flow under inappropriate conditions

  19. Floating Drug Delivery Systems: A Review

    Directory of Open Access Journals (Sweden)

    Babariya Nimeshkumar Arvindbhai

    2013-01-01

    Full Text Available Purpose of writing this review on floating drug delivery system was to focus on the principle mechanism of floatation to achieve gastric retention. Technological attempts have been made in the research and development of rate controlled oral drug delivery system to overcome physiological adversities, such as short gastric residence time (GRT and unpredictable gastric emptying times. It is new drug delivery system maximize effectiveness and compliance. This review summarizes advantages of floating drug delivery system approaches to design single unit and multiple unit floating system, in-vitro and in-vivo technology to evaluate the performance of floating system. At attempt has been made in this review article to introduce the readers to current development in floating drug delivery system.

  20. Hydraulic Characteristics of a Stepped-slope Floating Breakwater

    International Nuclear Information System (INIS)

    A stepped-slope floating breakwater is developed to provide wave protection to small ports and harbours. The width of the structure can be enhanced by increasing the number of breakwater units that are placed side-by-side to each other. This produces three types of test model, i.e. single-row, double-row and triple-row breakwaters. The test models have been tested in monochromatic waves in a wave flume to determine their hydraulic performance in various wave conditions. The incident and reflected wave profiles in the vicinity of the test models are recorded and analysed by using moving-probe method. The hydraulic performance of the test models are quantified by the coefficients of transmission, reflection and energy loss. The experimental results showed that the stepped-slope floating breakwater is an effective anti-reflection structure and a reasonably good wave attenuator.

  1. Macro-Encapsulated PCM Cylinder Module Based on Paraffin and Float Stones

    OpenAIRE

    Kailiang Huang; Dong Liang; Guohui Feng; Mingzhi Jiang; Yuhua Zhu; Xin Liu; Bian Jiang

    2016-01-01

    Organic phase change material (PCM) with macro-encapsulation is attractive in energy storage applications as it has relatively low cost. This study focuses on using PET plastic pipes to encapsulate paraffin and using low-cost float stones to increase the thermal conductivity of PCM modules as they have a special structure of high porosity. Float stones were immersed in the liquid PCM and an ultrasonic welding method used to prevent leakage of the PET plastic pipes. Scanning electron microscop...

  2. Some Aspects of Mega-Floating Airport Design and Production

    OpenAIRE

    Hadžić, Neven; Tomić, Marko; Vladimir, Nikola; Senjanović, Ivo

    2016-01-01

    Mega-Floating Airports (MFA) are unique and complex offshore transport system components that emerged as a consequence of tremendous land price increase in the vicinity of very large coastal cities. An overview of MFAs design and production aspects is presented within this paper including design concept, model tests and full scale measurement, air transport analysis, infrastructure, main particulars and structure, wave breaker, hydroelastic analysis due to wave load and airplane moving ...

  3. Of floating-zone uranium

    International Nuclear Information System (INIS)

    The floating zone method has been chosen in order to purify uranium. The various parameters occurring in this purification technique, have been studied theoretically and technologically. The speed that proves to be the most efficient is 0,7 cm/h, the direction can only upwards, and the fusion must take place under pressure of 10-7 Torr or so. Besides such problems concerning purification, the study of the floating zone stability led us to define a field touching the size and diameter of uranium drops, which, on the one hand coincides with Heywang's conditions and, on the other hand, is compatible with a fusion in the core of the bar. Such field shows that the floating zone can easily apply to bars whose diameter is included between 5 and 10 mm, and that it cannot work out when the diameter exceeds 21 mm. The apparatus, consisting in a means of heating by electronic bombardment under ultra-vacuum is conditioned by the various parameters that have been studied. As the analysis results were insufficient, the uranium thus dealt with has been characterized by metallurgic and physical tests: micrographic tests, measures of microhardness, measures of electric resistivity at a low temperature, have shown a definite purification at the bar-head; these results have been confirmed by the lowering at 270 C of the temperature of recrystallization together with the definite tendency of the refined metal to polygonize. The measures of electric resistivity constitute an easy and quantitative way of figuring out the metal purity. The influence of an impurity on the electric resistivity of uranium has been studied by U-Au alloys with a weak concentration of gold. The two important following points are brought out be these experiences: 1 - the measure of electric resistivity should be worked out on anneal bars in γ phase and cooled. 2 - Gold has a very strong influence on uranium; the value 500 μωcm per cent of gold enabled us to give a total concentration of 20 to 30 ppm of

  4. Assessing Fatigue and Ultimate Load Uncertainty in Floating Offshore Wind Turbines Due to Varying Simulation Length

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, G.; Lackner, M.; Haid, L.; Matha, D.; Jonkman, J.; Robertson, A.

    2013-07-01

    With the push towards siting wind turbines farther offshore due to higher wind quality and less visibility, floating offshore wind turbines, which can be located in deep water, are becoming an economically attractive option. The International Electrotechnical Commission's (IEC) 61400-3 design standard covers fixed-bottom offshore wind turbines, but there are a number of new research questions that need to be answered to modify these standards so that they are applicable to floating wind turbines. One issue is the appropriate simulation length needed for floating turbines. This paper will discuss the results from a study assessing the impact of simulation length on the ultimate and fatigue loads of the structure, and will address uncertainties associated with changing the simulation length for the analyzed floating platform. Recommendations of required simulation length based on load uncertainty will be made and compared to current simulation length requirements.

  5. Extended Onshore Control of a Floating Wind Turbine with Wave Disturbance Reduction

    International Nuclear Information System (INIS)

    Reaching for higher wind resources beyond the water depth limitations of monopile wind turbines, there has arisen the alternative of using floating wind turbines. But the response of wave induced loads significantly increases for floating wind turbines. Applying conventional onshore control strategies to floating wind turbines has been shown to impose negative damped oscillations in fore-aft due to the low natural frequency of the floating structure. Thus, we suggest a control loop extension of the onshore controller which stabilizes the system and reduces the wave disturbance. The results shows that when adding the suggested control loop with disturbance reduction to the system, improved performance is observed in power fluctuations, blade pitch activity, and platform oscillations

  6. Extended Onshore Control of a Floating Wind Turbine with Wave Disturbance Reduction

    Science.gov (United States)

    Christiansen, S.; Knudsen, T.; Bak, T.

    2014-12-01

    Reaching for higher wind resources beyond the water depth limitations of monopile wind turbines, there has arisen the alternative of using floating wind turbines. But the response of wave induced loads significantly increases for floating wind turbines. Applying conventional onshore control strategies to floating wind turbines has been shown to impose negative damped oscillations in fore-aft due to the low natural frequency of the floating structure. Thus, we suggest a control loop extension of the onshore controller which stabilizes the system and reduces the wave disturbance. The results shows that when adding the suggested control loop with disturbance reduction to the system, improved performance is observed in power fluctuations, blade pitch activity, and platform oscillations.

  7. Dynamic Response of Large Box-shaped Inverted Siphon under Complex Geological Conditions%复杂地质条件下大型箱型倒虹吸动力响应研究

    Institute of Scientific and Technical Information of China (English)

    王慧; 李晓克; 赵顺波

    2011-01-01

    For studying the dynamic response of the large inverted siphon under complex geological conditions, a FEM dynamic analysis model is established after considering the fluid-structure interaction. Based on the time-history method, the structural dynamic stresses and displacements in different soil distributions are analyzed and the distributions of the dynamic response under different geological conditions are obtained. The calculation shows that the structural performance can be improved by replacing soil.%针对大型倒虹吸在复杂地质条件下的动响应问题,建立了考虑流固耦合作用的倒虹吸结构动力分析有限元模型.基于时程分析方法,对不同土层分布下结构的动应力及动位移进行分析.计算得出各地质条件下的动力响应分布规律,并表明通过换填土可以改善结构动力性能.

  8. Renewable Energy Based Floating Power Generator (Rivers and Canals

    Directory of Open Access Journals (Sweden)

    Dr. J.R.Gandhi

    2016-02-01

    Full Text Available We have developed a stand alone, (river and canal water stream floating power generator system for village electrification, agriculture water pumping, bridge street lights and such other utilities. The system is the unique one of its kind as per our knowledge and various surveys. The physical structure of the system is made of the non corrosive and unbreakable materials like mild steel, fiber glass etc. It works, as it rotates in the water flow. It does not require any kind of the external electric grid power for its working. As the water flows, the specially designed blades of the system rotate in the direction of the flow and ultimately the consistent power is generated, this power can be used directly or it may be stored in battery and the utilized as and when required. No permanent installation, No pollution and environment friendly floating Pico turbine. The observations taken from the sight are tabulated and accordingly results are discussed.

  9. 14 CFR 27.751 - Main float buoyancy.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float buoyancy. 27.751 Section 27.751 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 27.751 Main float buoyancy. (a) For main floats, the...

  10. 14 CFR 29.751 - Main float buoyancy.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float buoyancy. 29.751 Section 29.751 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.751 Main float buoyancy. (a) For main floats,...

  11. 14 CFR 25.751 - Main float buoyancy.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float buoyancy. 25.751 Section 25.751 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Floats and Hulls § 25.751 Main float buoyancy. Each main float must have— (a)...

  12. A Novel Ideal Floating Inductor Using Translinear Conveyors

    OpenAIRE

    Iqbal A. Khan; Mehmood H. Zaidi

    2003-01-01

    An ideal floating inductor circuit using translinear conveyors is introduced. The floating inductor simulator uses two translinear conveyors and a single capacitor in its realization. The circuit provides the current controlled ideal floating inductance without any component matching constraints. Simulation results on the floating inductor simulator verify the theory

  13. 14 CFR 23.753 - Main float design.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 23.753 Section 23.753... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Floats and Hulls § 23.753 Main float design. Each seaplane main float must meet the requirements of § 23.521....

  14. 北冰洋80°~85°N浮冰区对流层大气的垂直结构%Vertical structure of troposphere in the floating ice zone over the Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    马永锋; 卞林根; 周秀骥; 逯昌贵; 窦挺峰; 汤洁

    2011-01-01

    利用2008年夏季中国第3次北冰洋考察所获取的GPS探空资料对北冰洋(79°~85.5°N,144°~170°W)浮冰区对流层大气的垂直结构进行了研究.结果表明:北冰洋浮冰区对流层中部大气的平均温度递减率为6.47℃/km;对流层顶高度为8.0~10.7 km,平均为9.3 km,对流层顶温度为-59.4~-43.5℃,平均约-50.5℃;边界层中强逆温层层底高度、逆温强度和边界层高度均存在明显的日变化特征,强逆温层层底高度和边界层高度在夜间分别约为700和800 m,白天随着太阳辐射的加强在午后两者分别可抬升至850和1 000 m以上,逆温强度则由夜间向白天明显减弱.%The vertical structure of troposphere over the Arctic Ocean floating ice region (79~85.5°N, 144°~ 170°W) is presented by using the GPS radiosonde data obtained from the 3rd Chinese Arctic Expedition 2008.The results show that: the average temperature lapse rate of the middle troposphere is 6.47 ℃/ km.The tropopause height (temperature) changes within 8.0~ 10.7 km(- 59.4~ - 43.5 ℃), with a mean of 9.3 km(-50.5 ℃).The bottom height, strength of the stronger inversion in the boundary layer and the planetary boundary layer height all presents an obvious diurnal variation.The stronger inversion bottom height and the planetary boundary layer height are left to 850 and 1 000 m above at noon from~700 and 800 m at night, respectively.While the intensity of temperature inversion remarkably weakened from night to daytime.

  15. Floating turbines. Lying statically on the waves

    Energy Technology Data Exchange (ETDEWEB)

    Koenemann, Detlef

    2012-07-01

    There is great untapped wind potential for development off the coasts of Europe. If we succeed in stabilising floating wind turbines in moving waters, huge wind farms could be built despite the very deep waters. (orig.)

  16. Validation of salinity data from ARGO floats: Comparison between the older ARGO floats and that of later deployments

    Digital Repository Service at National Institute of Oceanography (India)

    Youn, Y.-H.; Lee, H.; Chang, Y.-S.; Pankajakshan, T.

    depolyed in different years. Floats deployed in the East Sea and the Indian Ocean are examined to find out float-to-float match-ups in such a way that an older float pops up simultaneously with a newer deployment (with tolerable space-time difference). A...

  17. The mirage of floating exchange rates

    OpenAIRE

    Reinhart, Carmen

    2000-01-01

    This note summarizes some of the highlights of my longer paper with Guillermo Calvo”Fear of Floating.” Many emerging market countries have suffered financial crises. One view blames soft pegs for these crises. Adherents to that view suggest that countries move to corner solutions--hard pegs or floating exchange rates. We analyze the behavior of exchange rates, reserves, and interest rates to assess whether there is evidence that country practice is moving toward corner solutions. We focus on...

  18. Travel Time Estimation Using Floating Car Data

    CERN Document Server

    Sevlian, Raffi

    2010-01-01

    This report explores the use of machine learning techniques to accurately predict travel times in city streets and highways using floating car data (location information of user vehicles on a road network). The aim of this report is twofold, first we present a general architecture of solving this problem, then present and evaluate few techniques on real floating car data gathered over a month on a 5 Km highway in New Delhi.

  19. Fear of Floating and Social Welfare

    OpenAIRE

    Demosthenes N. Tambakis

    2007-01-01

    This paper studies the welfare implications of financial stability and inflation stabilization as distinct monetary policy objectives. Introducing asymmetric aversion to exchange rate depreciation in the Barro-Gordon model mitigates inflation bias due to credibility problems. The net welfare impact of fear of floating depends on the economy's recent track record, the credibility of monetary policy, and the central bank's discount factor. It is shown that fear of floating is more appropriate f...

  20. Floating island for extracting or processing gas

    Energy Technology Data Exchange (ETDEWEB)

    Poeppel, F.O.

    1979-09-25

    The described floating island for the extraction of gas from the sea a plurality of buoyancy units positioned on a base plate with columns extending upward therefrom at a height approximately the wave height expected. A platform containing gas liquefaction apparatus is positioned on the top of the columns. The buoyancy units are selected so that when the island is free floating, the columns project more than half way from the water.

  1. Integrated optimization of floating wind turbine systems

    OpenAIRE

    Sandner, Frank; Schlipf, David; Matha, Denis; Cheng, Po Wen

    2014-01-01

    An exemplary methodology is shown for the integrated conceptioning of a floating wind turbine system with focus on the spar-type hull and the wind turbine blade-pitch-to-feather controller. It is a special interest to use a standard controller, which is easily implementable, even at early design stages. The optimization of the system is done with adapted static and dynamic models through a stepwise narrowing of the design space according to the requirements of floating wind turbines. After se...

  2. Floating wetlands for urban stormwater treatment

    OpenAIRE

    Wang, Chih-Yu

    2013-01-01

    A floating treatment wetland (FTW) is an ecological approach which seeks to reduce point and nonpoint source pollution by installing substrate rooted plants grown on floating mats in open waters. While relatively novel, FTW use is increasing. A review of literature identified several research gaps, including: (1) assessments of the treatment performance of FTWs; (2) evaluations of FTWs in the U.S., particularly within wet ponds that receive urban runoff; and (3) plant temporal nutrient distri...

  3. Archimedes' floating bodies on a spherical Earth

    Science.gov (United States)

    Rorres, Chris

    2016-01-01

    Archimedes was the first to systematically find the centers of gravity of various solid bodies and to apply this concept in determining stable configurations of floating bodies. In this paper, we discuss an error in a proof developed by Archimedes that involves determining whether a uniform, spherical cap will float stably with its base horizontal in a liquid on a spherical Earth. We present a simpler, corrected proof and discuss aspects of his proof regarding a spherical cap that is not uniform.

  4. FLOAT - development of new flexible UHPC. Final report. [Ultra High Performance Fibre Reinforced Concrete

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-11-01

    that simply by using a steel fibre with a smaller diameter, it may be possible to decrease the wall thickness of a Wave Star float by approximately 15% and thus save on weight. Preliminary experience with concrete - and especially UHPC for off shore applications are described. Emphasis is placed on description of production of a 1:10 scale float in CRC, installing the float at the test site and the results of close to 4 years of exposure. For Dexa Wave there is no advantage of using CRC for the floats, and with the short time available it has not been possible to do an assessment of whether other parts of the structure could benefit from replacing other materials with CRC. For Wave Star there is a significant advantage. For the floats - and there are 20 to each converter - there is a 77% saving in price, which means a saving of 4,8 mio. kr. for one converter. A study has also been made for the arm that holds the float, and in this case the reduction in cost is estimated at 45%, or 1,6 mio. kr for the converter. The current project has indicated that the first steps to meeting one of the main challenges - lowering machine costs - is possible for certain types of WEC, but it has also been shown that replacing other materials with CRC is not a universal solution. For the Dexa Wave converter there is no advantage in using CRC for the floats, but as for the Wave Star converter, there could still be advantages in replacing other structural parts of the converter. (LN)

  5. Sensitivity analysis of floating offshore wind farms

    International Nuclear Information System (INIS)

    Highlights: • Develop a sensitivity analysis of a floating offshore wind farm. • Influence on the life-cycle costs involved in a floating offshore wind farm. • Influence on IRR, NPV, pay-back period, LCOE and cost of power. • Important variables: distance, wind resource, electric tariff, etc. • It helps to investors to take decisions in the future. - Abstract: The future of offshore wind energy will be in deep waters. In this context, the main objective of the present paper is to develop a sensitivity analysis of a floating offshore wind farm. It will show how much the output variables can vary when the input variables are changing. For this purpose two different scenarios will be taken into account: the life-cycle costs involved in a floating offshore wind farm (cost of conception and definition, cost of design and development, cost of manufacturing, cost of installation, cost of exploitation and cost of dismantling) and the most important economic indexes in terms of economic feasibility of a floating offshore wind farm (internal rate of return, net present value, discounted pay-back period, levelized cost of energy and cost of power). Results indicate that the most important variables in economic terms are the number of wind turbines and the distance from farm to shore in the costs’ scenario, and the wind scale parameter and the electric tariff for the economic indexes. This study will help investors to take into account these variables in the development of floating offshore wind farms in the future

  6. DEVELOPMENT AND OPTIMIZATION OF FLOATING MICROSPHERES OF GLICLAZIDE

    Directory of Open Access Journals (Sweden)

    Shardendu Prakash

    2015-05-01

    Full Text Available The objective of the present study was to develop floating microspheres of Gliclazide in order to achieve an extended retention in the upper gastrointestinal tract, which may result in enhanced absorption and thereby improved bioavailability. The present study involves preparation and evaluation of floating microspheres using Gliclazide as a model drug for prolongation of the gastric retention time. As gliclazide is mainly absorbed from stomach, thus using floating microspheres as a mode of drug delivery helps in increasing its residence time and hence increasing the bioavailability of drug. The microspheres were prepared by the Ionic gelation method. The average diameter and surface morphology of the prepared microspheres were characterized by optical microscope and scanning electron microscopic methods respectively. The prepared microspheres were evaluated for particle size, micromeritic study, drug entrapment efficiency, in vitro buoyancy, swelling index and in vitro release. The effect of various formulation variables on the size and drug release was also investigated. All the formulated microspheres were found to possess good flow properties. Scanning electron microscopy confirmed spherical structure of the prepared microspheres. The best formulation F3 drug release kinetics were evaluated using Zero order, First order, Higuchi model, Korsmeyer - Peppas model. After the interpretation of data that was based on the value of a resulting regression coefficient, it was observed that the Korsmeyer- Peppas model has a highest regression coefficient values indicating that the drug release was based on the erosion of polymeric chain matrix.

  7. Exponential flux-controlled memristor model and its floating emulator

    Science.gov (United States)

    Liu, Wei; Wang, Fa-Qiang; Ma, Xi-Kui

    2015-11-01

    As commercial memristors are still unavailable in the market, mathematic models and emulators which can imitate the features of the memristor are meaningful for further research. In this paper, based on the analyses of characteristics of the q-φ curve, an exponential flux-controlled model, which has the quality that its memductance (memristance) will keep monotonically increasing or decreasing unless the voltage’s polarity reverses (if not approach the boundaries), is constructed. A new approach to designing the floating emulator of the memristor is also proposed. This floating structure can flexibly meet various demands for the current through the memristor (especially the demand for a larger current). The simulations and experiments are presented to confirm the effectiveness of this model and its floating emulator. Project supported by the National Natural Science Foundation of China (Grant Nos. 51377124 and 51221005), the Foundation for the Author of National Excellent Doctoral Dissertation of China (Grant No. 201337), the Program for New Century Excellent Talents in University of China (Grant No. NCET-13-0457), and the Natural Science Basic Research Plan in Shaanxi Province of China (Grant No. 2012JQ7026).

  8. Cascade Analysis of a Floating Wind Turbine Rotor

    International Nuclear Information System (INIS)

    Mounting a wind turbine on a floating foundation introduces more complexity to the aerodynamic loading. The floater motion contains a wide range of frequencies. To study some of the basic dynamic load effect on the blades due to these motions, a two-dimensional cascade approach, combined with a potential vortex method, is used. This is an alternative method to study the aeroelastic behavior of wind turbines that is different from the traditional blade element momentum method. The analysis tool demands little computational power relative to a full three dimensional vortex method, and can handle unsteady flows. When using the cascade plane, a ''cut'' is made at a section of the wind turbine blade. The flow is viewed parallel to the blade axis at this cut. The cascade model is commonly used for analysis of turbo machineries. Due to the simplicity of the code it requires little computational resources, however it has limitations in its validity. It can only handle two-dimensional potential flow, i.e. including neither three-dimensional effects, such as the tip loss effect, nor boundary layers and stall effects are modeled. The computational tool can however be valuable in the overall analysis of floating wind turbines, and evaluation of the rotor control system. A check of the validity of the vortex panel code using an airfoil profile is performed, comparing the variation of the lift force, to the theoretically derived Wagner function. To analyse the floating wind turbine, a floating structure with hub height 90 m is chosen. An axial motion of the rotor is considered

  9. Cascade Analysis of a Floating Wind Turbine Rotor

    Science.gov (United States)

    Eliassen, Lene; Jakobsen, Jasna B.; Knauer, Andreas; Nielsen, Finn Gunnar

    2014-12-01

    Mounting a wind turbine on a floating foundation introduces more complexity to the aerodynamic loading. The floater motion contains a wide range of frequencies. To study some of the basic dynamic load effect on the blades due to these motions, a two-dimensional cascade approach, combined with a potential vortex method, is used. This is an alternative method to study the aeroelastic behavior of wind turbines that is different from the traditional blade element momentum method. The analysis tool demands little computational power relative to a full three dimensional vortex method, and can handle unsteady flows. When using the cascade plane, a "cut" is made at a section of the wind turbine blade. The flow is viewed parallel to the blade axis at this cut. The cascade model is commonly used for analysis of turbo machineries. Due to the simplicity of the code it requires little computational resources, however it has limitations in its validity. It can only handle two-dimensional potential flow, i.e. including neither three-dimensional effects, such as the tip loss effect, nor boundary layers and stall effects are modeled. The computational tool can however be valuable in the overall analysis of floating wind turbines, and evaluation of the rotor control system. A check of the validity of the vortex panel code using an airfoil profile is performed, comparing the variation of the lift force, to the theoretically derived Wagner function. To analyse the floating wind turbine, a floating structure with hub height 90 m is chosen. An axial motion of the rotor is considered.

  10. 悬浮隧道锚索流固耦合振动试验研究%Experiments on dynamic fluid-structure coupled responses of anchor cables of submerged floating tunnel

    Institute of Scientific and Technical Information of China (English)

    晁春峰; 项贻强; 杨超

    2016-01-01

    悬浮隧道跨越长深水域的新型交通结构物。在水流的作用下,锚索将会发生涡激振动,以往的研究主要采用数值方法,而进行模型试验研究是探索悬浮隧道锚索涡激振动机理不可或缺的研究手段之一。利用风浪流多功能水槽,以千岛湖悬浮隧道锚索为原型,采用节段模型试验的方法,进行了均匀流作用下锚索涡激振动试验研究。通过试验发现,圆形锚索的 Cm值约为0.94,线性流体阻尼比ξ′约为1.26%;锚索在约化速度 U/fn D =5.8~10.1发生涡激锁定现象,产生涡激共振,此时横向振幅约化值(Ay /D)最大达到1.10,顺流向振动依旧较小,而升力系数 CL和拖曳力系数 CD均会显著的增大;参数分析发现,圆形锚索倾斜布置有利于降低涡激共振的不利影响,但当来流角度的变化后会对倾斜布置的锚索产生不利影响。%Submerged floating tunnel(SFT)is a new traffic structure across long and deep waterway.The vortex-induced vibration (VIV)of cables may occur under the action of water current.Even through numerous previous studies have been done by using numerical methods,however,experiment is an indispensable mean to explore the VIV mechanism of cables in water.Taking the cables of Qiandao Lake SFT as the prototype,the experiments of VIV on cables were carried out under the action of current by using segment models in a stormy stream integrated sink.The results show that the inertial force coefficient Cm of circular cable is 0.94,the linear fluid damping ratio ξ'is 1 .26%;when the reduced velocity is between 5.8 and 1 0.1 ,the vortex-induced resonance will occur,the maximum lateral amplitude Ay /D is 1 .1 0,the in-line amplitude is still low,and the lift coefficient CL and drag coefficient CD obviously increase.By the parametric analysis it is concluded that the diagonal arrangement of circular cables is helpful to reduce the VIV effects and

  11. Battery charging in float vs. cycling environments

    Energy Technology Data Exchange (ETDEWEB)

    COREY,GARTH P.

    2000-04-20

    In lead-acid battery systems, cycling systems are often managed using float management strategies. There are many differences in battery management strategies for a float environment and battery management strategies for a cycling environment. To complicate matters further, in many cycling environments, such as off-grid domestic power systems, there is usually not an available charging source capable of efficiently equalizing a lead-acid battery let alone bring it to a full state of charge. Typically, rules for battery management which have worked quite well in a floating environment have been routinely applied to cycling batteries without full appreciation of what the cycling battery really needs to reach a full state of charge and to maintain a high state of health. For example, charge target voltages for batteries that are regularly deep cycled in off-grid power sources are the same as voltages applied to stand-by systems following a discharge event. In other charging operations equalization charge requirements are frequently ignored or incorrectly applied in cycled systems which frequently leads to premature capacity loss. The cause of this serious problem: the application of float battery management strategies to cycling battery systems. This paper describes the outcomes to be expected when managing cycling batteries with float strategies and discusses the techniques and benefits for the use of cycling battery management strategies.

  12. Formulation and optimization of carbamazepine floating tablets

    Directory of Open Access Journals (Sweden)

    Patel D

    2007-01-01

    Full Text Available Floating tablets of carbamazepine were developed using melt granulation technique. Bees wax was used as a hydrophobic meltable material. Hydroxypropylmethylcellulose, sodium bicarbonate and ethyl cellulose were used as matrixing agent, gas-generating agent and floating enhancer, respectively. The tablets were evaluated for in vitro buoyancy and dissolution studies. A simplex lattice design was applied to investigate the combined effect of 3 formulation variables i.e. amount of hydroxypropyl methylcellulose ( X 1 , ethyl cellulose ( X 2 and sodium bicarbonate ( X 3 . The floating lag time (F lag , time required for 50% (t 50 and 80% drug dissolution (t 80 were taken as responses. Results of multiple regression analysis indicated that, low level of X 1 and X 2 , and high level of X 3 should be used to manufacture the tablet formulation with desired in vitro floating time and dissolution. Formulations developed using simplex lattice design were fitted to various kinetic models for drug release. Formulation S3 was selected as a promising formulation and was found stable at 40 o and 75% relative humidity for 3 months. Present study demonstrates the use of simplex lattice design in the development of floating tablets with minimum experimentation.

  13. FLOATING DRUG DELIVERY SYSTEM: A REVIEW

    Directory of Open Access Journals (Sweden)

    Kataria Sahil

    2011-09-01

    Full Text Available The recent scientific and patented literature concluded that an increased interest in novel dosage forms which retained in the stomach for prolong and predictable period of time has been shown. Various technological attempts have been made in the research and development of rate-controlled oral drug delivery systems to overcome physiological diversities, as short gastric residence times and unpredictable gastric emptying times using gastro retentive drug delivery system. It is a well known fact that differences in gastric physiology, such as, gastric pH and motility exhibit both intra as well as inter-subject variability demonstrating significant impact on gastric retention time and drug delivery behavior. Various attempts have been made to develop Gastro retentive delivery systems. Several approaches are currently utilized in the prolongation of the GRT, including floating drug delivery systems, swelling and expanding systems, polymeric bio adhesive systems, high-density systems, modified-shape systems and other delayed gastric emptying devices. Floating dosage forms are emerging as a promising dosage forms. Floating dosage form can be prepared as tablets, capsules by adding suitable ingredients as well as by adding gas generating agent. In this review various techniques used in floating dosage forms along with current & recent developments of stomach specific floating drug delivery system for gastro retention are discussed.

  14. Floating debris in the Mediterranean Sea.

    Science.gov (United States)

    Suaria, Giuseppe; Aliani, Stefano

    2014-09-15

    Results from the first large-scale survey of floating natural (NMD) and anthropogenic (AMD) debris (>2 cm) in the central and western part of the Mediterranean Sea are reported. Floating debris was found throughout the entire study area with densities ranging from 0 to 194.6 items/km(2) and mean abundances of 24.9 AMD items/km(2) and 6.9 NMD items/km(2) across all surveyed locations. On the whole, 78% of all sighted objects were of anthropogenic origin, 95.6% of which were petrochemical derivatives (i.e. plastic and styrofoam). Maximum AMD densities (>52 items/km(2)) were found in the Adriatic Sea and in the Algerian basin, while the lowest densities (litter items are currently floating on the surface of the whole Mediterranean basin. PMID:25127501

  15. Russians float their APWS-40 idea

    International Nuclear Information System (INIS)

    A project of development of floating complexes producing drinking water from seawater is under way in Russia. Designed particularly for the Mediterranean, the APWS-40 nuclear-driven floating desalination plant will be equipped with two KLT-40 type reactors and four desalination units. With a staff of 60, the floating plant will be able to supply 80 000 m3 drinking water for 25 years, using a 2-3 year nuclear fuel cycle. Only one major outage is planned within the whole service life of the facility. Special care will be paid to nuclear safety. It is noted that desalination is an issue of interest fostered by the IAEA. (P.A.). 2 figs

  16. Floating mechanism of a small liquid marble

    Science.gov (United States)

    Ooi, Chin Hong; Plackowski, Chris; Nguyen, Anh V.; Vadivelu, Raja K.; John, James A. St.; Dao, Dzung Viet; Nguyen, Nam-Trung

    2016-02-01

    Flotation of small solid objects and liquid droplets on water is critical to natural and industrial activities. This paper reports the floating mechanism of liquid marbles, or liquid droplets coated with hydrophobic microparticles. We used X-ray computed tomography (XCT) to acquire cross-sectional images of the floating liquid marble and interface between the different phases. We then analysed the shape of the liquid marble and the angles at the three-phase contact line (TPCL). We found that the small floating liquid marbles follow the mechanism governing the flotation of solid objects in terms of surface tension forces. However, the contact angles formed and deformation of the liquid marble resemble that of a sessile liquid droplet on a thin, elastic solid. For small liquid marbles, the contact angle varies with volume due to the deformability of the interface.

  17. Feasibility study on nuclear floating island (NUFIS)

    Energy Technology Data Exchange (ETDEWEB)

    Murata, H.; Taketani, K. (Japan Atomic Energy Research Inst., Tokai, Ibaraki. Tokai Research Establishment); Morozumi, M.; Katayama, M.

    1981-02-01

    Under the present oil demand/supply situation, oil consumption must be reduced in Japan, implying the reliance on nuclear energy in future. The siting for nuclear power plants is limited, however, because of the dense population; there must emerge a new concept in this connection. Feasibility of a nuclear floating island (NUFIS) has been studied. The NUFIS is located about 20 km offshore with sea depth about 150 m and has a 1,200 MWe PWR plant on a 140 m x 140 m floating platform, with displacement about 298,000 t. It is technologically feasible, and the platform is stable enough to build the power plant and its associated facilities on it. It is possible to construct a nuclear floating center offshore of Japan, which comprises VHTR, FBR, fuel reprocessing and fabrication plants.

  18. Feasibility study on nuclear floating island (NUFIS)

    International Nuclear Information System (INIS)

    Under the present oil demand/supply situation, oil consumption must be reduced in Japan, implying the reliance on nuclear energy in future. The siting for nuclear power plants is limited, however, because of the dense population; there must emerge a new concept in this connection. Feasibility of a nuclear floating island (NUFIS) has been studied. The NUFIS is located about 20 km offshore with sea depth about 150 m and has a 1,200 MWe PWR plant on a 140 m x 140 m floating platform, with displacement about 298,000 t. It is technologically feasible, and the platform is stable enough to build the power plant and its associated facilities on it. It is possible to construct a nuclear floating center offshore of Japan, which comprises VHTR, FBR, fuel reprocessing and fabrication plants. (author)

  19. A novel floating controlled release drug delivery system prepared by hot-melt extrusion.

    Science.gov (United States)

    Vo, Anh Q; Feng, Xin; Morott, Joseph T; Pimparade, Manjeet B; Tiwari, Roshan V; Zhang, Feng; Repka, Michael A

    2016-01-01

    Floating dosage forms are an important formulation strategy for drugs with a narrow absorption window and low intestinal solubility, and for localized gastric treatment. Novel floating pellets were prepared using the hot-melt extrusion (HME) technology. Uniformly foamed strands were created by liquid injection pumping and screw configuration modification. The ammonio methacrylate copolymer (Eudragit® RSPO) foaming structure was formed by a liquid-vapor phase transition inside the strand upon die exiting resulting from the sudden decrease in external pressure, vaporizing the liquid ethanol and vacating the extruded material. This generated uniform vacuous regions in the extrudate. The pellets' internal structure was investigated using scanning electron microscopy (SEM). The formulation constituents' and processing parameters' effects on the drug release profiles, floating force, and the pellets' micromeritic properties were evaluated by design of experiments: all formulations showed zero lag time and excellent floating strength, indicating immediate-floating pellet formation. The pellets' drug release profiles were controlled by multiple independent variables at different time points (⩽ 24 h). Drug loading significantly affected drug release within the first hour, the hydroxypropyl methylcellulose (HPMC) content thereafter. Understanding the variables' effects on the formulations allows for the tailoring of this delivery system to obtain various drug release profiles. PMID:26643801

  20. Functional verification of floating point arithmetic unit

    International Nuclear Information System (INIS)

    For continuous real-time reactivity monitoring of PFBR reactivity safety channel, a FPGA based reactivity meter has been developed by Electronics Division, BARC. Verification of designs involved in Safety Critical systems is very important and necessary. Functional verification of this design is presently carried out by EID, IGCAR. In Reactivity meter, Floating Point Arithmetic Unit (FPAU) is a major and very important sub module, which needs to be completely verified first. Two types of verifications are possible: Functional verification and Formal verification. This paper discusses and shares the experiences of functional verification of FPAU module for all special floating point numbers. (author)

  1. FLOAT2 WP4: Development of Materials

    DEFF Research Database (Denmark)

    Esteves, Luis Pedro; Aarup, Bendt

    This report refers to complementary material testing to support the design and production of UHPC floaters for installation in the Wave Star Machine under FLOAT2 project. The main objective of WP4 is the characterization of mechanical properties of fiber-reinforced UHPC.......This report refers to complementary material testing to support the design and production of UHPC floaters for installation in the Wave Star Machine under FLOAT2 project. The main objective of WP4 is the characterization of mechanical properties of fiber-reinforced UHPC....

  2. Argo Float Data from the APDRC DAPPER Server

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The floats are designed to drift at a fixed pressure (usually 1000 dbar) for 10 days. After this period, the floats move to a profiling pressure (usually between...

  3. Coupled Dynamic Modeling of Floating Wind Turbine Systems: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wayman, E. N.; Sclavounos, P. D.; Butterfield, S.; Jonkman, J.; Musial, W.

    2006-03-01

    This article presents a collaborative research program that the Massachusetts Institute of Technology (MIT) and the National Renewable Energy Laboratory (NREL) have undertaken to develop innovative and cost-effective floating and mooring systems for offshore wind turbines in water depths of 10-200 m. Methods for the coupled structural, hydrodynamic, and aerodynamic analysis of floating wind turbine systems are presented in the frequency domain. This analysis was conducted by coupling the aerodynamics and structural dynamics code FAST [4] developed at NREL with the wave load and response simulation code WAMIT (Wave Analysis at MIT) [15] developed at MIT. Analysis tools were developed to consider coupled interactions between the wind turbine and the floating system. These include the gyroscopic loads of the wind turbine rotor on the tower and floater, the aerodynamic damping introduced by the wind turbine rotor, the hydrodynamic damping introduced by wave-body interactions, and the hydrodynamic forces caused by wave excitation. Analyses were conducted for two floater concepts coupled with the NREL 5-MW Offshore Baseline wind turbine in water depths of 10-200 m: the MIT/NREL Shallow Drafted Barge (SDB) and the MIT/NREL Tension Leg Platform (TLP). These concepts were chosen to represent two different methods of achieving stability to identify differences in performance and cost of the different stability methods. The static and dynamic analyses of these structures evaluate the systems' responses to wave excitation at a range of frequencies, the systems' natural frequencies, and the standard deviations of the systems' motions in each degree of freedom in various wind and wave environments. This article in various wind and wave environments. This article explores the effects of coupling the wind turbine with the floating platform, the effects of water depth, and the effects of wind speed on the systems' performance. An economic feasibility analysis of

  4. The Effect of Additional Mooring Chains on the Motion Performance of a Floating Wind Turbine with a Tension Leg Platform

    OpenAIRE

    Jinping Ou; Nianxin Ren; Yugang Li

    2012-01-01

    In this study, two types of floating offshore wind turbine (FOWT) systems were proposed: a traditional tension leg platform (TLP) type and a new TLP type with additional mooring chains. They were both based on the National Renewable Energy Laboratory 5 MW offshore wind turbine model. Taking the coupled effect of dynamic response of the top wind turbine, tower support structure and lower mooring system into consideration, not only were the 1/60 scale model tests for the two floating wind turbi...

  5. 40 CFR 63.1063 - Floating roof requirements.

    Science.gov (United States)

    2010-07-01

    ... constitutes inspection failure. (i) Stored liquid on the floating roof. (ii) Holes or tears in the primary or... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Floating roof requirements. 63.1063...) National Emission Standards for Storage Vessels (Tanks)-Control Level 2 § 63.1063 Floating...

  6. 40 CFR 65.44 - External floating roof (EFR).

    Science.gov (United States)

    2010-07-01

    ... operator shall visually inspect for EFR failures, the external floating roof, the primary seal, secondary... 40 Protection of Environment 15 2010-07-01 2010-07-01 false External floating roof (EFR). 65.44... (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Storage Vessels § 65.44 External floating roof (EFR). (a)...

  7. 14 CFR 23.751 - Main float buoyancy.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float buoyancy. 23.751 Section 23.751 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Floats and Hulls § 23.751 Main float buoyancy....

  8. 14 CFR 25.753 - Main float design.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 25.753 Section 25.753 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Floats and Hulls § 25.753 Main float...

  9. Reis kosmosesse : [Floating-kambrist] / Marika Makarova

    Index Scriptorium Estoniae

    Makarova, Marika

    2011-01-01

    Ameerika psühholoogi John C. Lilly poolt kasutusele võetud Floating-kambrist ehk hõljumisvannist, mis aeglustab ajulaineid ning seeläbi aitab vähendada lihaspinget, stressi, ärevust, peavalusid, vererõhku ning parandada und, selgroo- ja kaelavigastusi, suurendada loovust ja heaolu jne

  10. Floating car data for traffic monitoring

    DEFF Research Database (Denmark)

    Torp, Kristian; Lahrmann, Harry Spaabæk

    2005-01-01

    This paper describes a complete prototype system that uses Floating Car Data (FCD) for both automatic and manual detection of queues in traffic. The system is developed under EU’s Tempo program. The systems consists of small hardware units placed in mobile traffic report units (we use taxis...

  11. Floating convection barrier for evaporation source

    International Nuclear Information System (INIS)

    A floating matrix of titanium in an uranium evaporation source, melted by an electron beam, serves as a barrier for preventing cooler material from reaching the evaporation area. This construction allows a big volume of melted uranium to be present and new uranium to be furnished in regulated intervals without manual intervention

  12. Floating RC Networks Using Current Conveyors

    Directory of Open Access Journals (Sweden)

    V. Zeman

    1996-06-01

    Full Text Available The paper deals with the design of floating one- and/or two-port high-order networks. The current conveyor CCII+ seems to be a suitable active building block for this purpose. Some examples of the above mentioned networks are shown .

  13. A novel floating offshore wind turbine concept

    DEFF Research Database (Denmark)

    Vita, Luca; Schmidt Paulsen, Uwe; Friis Pedersen, Troels;

    2009-01-01

    This paper will present a novel concept of a floating offshore wind turbine. The new concept is intended for vertical-axis wind turbine technology. The main purpose is to increase simplicity and to reduce total costs of an installed offshore wind farm. The concept is intended for deep water and...

  14. FLOATING DRUG DELIVERY SYSTEM: A REVIEW

    Directory of Open Access Journals (Sweden)

    meenakshi bharkatiya

    2014-03-01

    Full Text Available The main goal of any drug delivery system is to achieve desired concentration of the drug in blood or tissue, which is therapeutically effective and non toxic for a prolonged period. Various attempts have been made to develop gastroretentive delivery systems such as high density system, swelling, floating system. The recent developments of FDDS including the physiological and formulation variables affecting gastric retention, approaches to design single-unit and multiple-unit floating systems, and their classification and formulation aspects are covered in detail. This review also summarizes the studies to evaluate the performance and application of floating systems, and applications of these systems. Gastric emptying is a complex process and makes in vivo performance of the drug delivery systems uncertain. In order to avoid this variability, efforts have been made to increase the retention time of the drug-delivery systems for more than 12 hours. The floating or hydrodynamically controlled drug delivery systems are useful in such application.

  15. Two New Families of Floating FDNR Circuits

    Directory of Open Access Journals (Sweden)

    Ahmed M. Soliman

    2010-01-01

    Full Text Available Two new configurations for realizing ideal floating frequency-dependent negative resistor elements (FDNR are introduced. The proposed circuits are symmetrical and are realizable by four CCII or ICCII or a combination of both. Each configuration is realizable by eight different circuits. Simulation results are included to support the theory.

  16. Near-Shore Floating Wave Energy Converters

    DEFF Research Database (Denmark)

    Ruol, Piero; Zanuttigh, Barbara; Martinelli, Luca;

    2011-01-01

    Aim of this note is to analyse the possible application of a Wave Energy Converter (WEC) as a combined tool to protect the coast and harvest energy. Physical model tests are used to evaluate wave transmission past a near-shore floating WEC of the wave activated body type, named DEXA. Efficiency a...

  17. Feasibility study on floating nuclear power plant (2). Safety design study of FNPP. Contract research

    International Nuclear Information System (INIS)

    In the previous report of 'Conceptual Design Study of FNPP (Floating Nuclear Power Plant)', a design study on a concept for FNPP, which is sited off the sea coast on the open sea with water depth of 20m and it is moored on protected sea by the breakwater was conducted and the floating platform guarded by the breakwater was found to be stable enough to install the nuclear power plant from analysis simulating the movement of the platform due to sea wave or wind. In this report, studies on a basic safety design concept of the FNPP, setting natural phenomena for design condition, required safety functions and a review on dynamic analysis of the large floating structure are presented. The studies revealed that the stability of the floating platform is an essential issue for the FNPP soundness, and the design base natural phenomena such as S1 and S2-class storm including S1 and S2-class earthquake should be considered in evaluation of the stability of the floating platform, and it is one of key technical subjects how to set the magnitude of these storm in application of design evaluation on each FNPP case. (J.P.N.)

  18. Effective Removal of Nitrogen and Phosphorus from Surface Water Using Constructed Comprehensive Floating Remediation Islands

    Science.gov (United States)

    Wang, M.; Bai, S.

    2008-12-01

    Nitrogen and phosphorus are the chief pollutants of our aquatic systems which may be resulted from different contamination sources and could cause serious environmental and ecological problems. For example, nitrate contamination of the water systems from agricultural practices may be contributing to the eutrophication of the Chesapeake Bay, Maryland, USA, degrading water quality and aquatic habitats. Effective approaches for removal of nitrogen and phosphorus from our aquatic systems, particularly from surface water, is called for imminently. An in-situ remediation measure by constructed floating remediation islands has been developed and tested through the field experiments recently. Four pilot-scale settings with the different components and structures were constructed and operated in parallel in which a new type of the constructed floating remediation islands with multi-layers of substrate fillers, called the constructed multi-layer comprehensive floating remediation island, was included. The contaminated water taken directly from a river containing richly nitrogen and phosphorus was used for those experiments. The experiment results obtained from the four different experiment settings were examined. It was noticed that the degradation rates of both nitrogen and phosphorus in water in the setting with the constructed multi-layer comprehensive floating remediation island was greater than those in others. The mean removal rate of phosphorous in the experiment setting with the constructed multi-layer comprehensive floating remediation island was considerably higher than the removal rates of phosphorous in the other three experiment settings.

  19. Free floating left atrial ball thrombus: a rare cause of stroke.

    Science.gov (United States)

    Rider, Oliver J; Malhotra, Aneil; Newton, James D

    2013-10-01

    In the setting of mitral valve stenosis and atrial fibrillation, left atrial ball thrombus is a rare but recognized cause of stroke and can occur even in the presence of therapeutic anticoagulation. This case report highlights the need for echocardiography to rule out treatable cardioembolic substrates for stroke. We report a case of cardioembolic stroke as a result of free floating left atrial ball thrombus presenting as a complication of rheumatic mitral valve disease. This case highlights that, in all patients with a history of structural heart disease, atrial fibrillation, or rheumatic fever, prompt cardiac ultrasound to exclude free floating atrial thrombus is essential. PMID:22959106

  20. Integrated Modelling Platform for Dynamic Performance Assessment of Floating Wind Turbines

    OpenAIRE

    Endegnanew, Atsede Gualu; Satertro, Kristian; Gjerde, Sverre Skalleberg; Svendsen, Harald Georg; Anaya-Lara, Olimpo; Tande, John Olav Giæver; Uhlen, Kjetil; Gjolmesli, Svein

    2015-01-01

    The paper presents an integrated modelling platform that can be used to assess the dynamic performance of an offshore wind turbine mounted on a spar-buoy type floater. Sub-models of generator and converter controllers and the power network are combined with a state-of-the-art numerical simulation of the hydro-, aero- and structural dynamic behavior of the floating wind turbine, using FEDEM Windpower software. The aim is to provide a tool that allows analyzing response of floating turbines to ...

  1. Factorial design approach for optimization of floating microspheres of diltiazem hydrochloride

    Directory of Open Access Journals (Sweden)

    Mangal Singh Panwar

    2015-01-01

    Full Text Available The aim of this study was to perform optimization of floating microspheres of diltiazem hydrochloride for the prolongation of gastric residence time. The microspheres were prepared by a nonaqueous solvent evaporation method using polycarbonate. A full factorial design was applied to optimize the formulation. Preliminary studies revealed that the concentration of polymer and stirring speed significantly affected the characteristics of floating microspheres. The optimum batch of microsphere exhibited smooth surfaces with good flow and packing properties, prolonged sustained drug release, remained buoyant for more than 10 h, high entrapment efficiency up to 97% w/w. Scanning electron microscopy confirmed the hollow structure with particle size in the order of 190 μm. The studies revealed that the increase in concentration of polycarbonate increased the drug release from the floating microspheres. The results of two third full factorial design revealed that the concentration of polycarbonate (X1 and stirring speed (X2 significantly affected drug entrapment efficiency, percentage release.

  2. Damping Wind and Wave Loads on a Floating Wind Turbine

    DEFF Research Database (Denmark)

    Christiansen, Søren; Bak, Thomas; Knudsen, Torben

    2013-01-01

    investigated, and we show the influence that both wind speed, wave frequencies and misalignment between wind and waves have on the system dynamics. A new control model is derived that extends standard turbine models to include the hydrodynamics, additional platform degrees of freedom, the platform mooring......Offshore wind energy capitalizes on the higher and less turbulent wind speeds at sea. To enable deployment of wind turbines in deep-water locations, structures are being explored, where wind turbines are placed on a floating platform. This combined structure presents a new control problem, due to...... the partly unconstrained movement of the platform and ocean wave excitation. If this additional complexity is not dealt with properly, this may lead to a significant increase in the structural loads and, potentially, instability of the controlled system. In this paper, the wave excitation is...

  3. A Method for Estimating the Probability of Floating Gate Prompt Charge Loss in a Radiation Environment

    Science.gov (United States)

    Edmonds, L. D.

    2016-01-01

    Because advancing technology has been producing smaller structures in electronic circuits, the floating gates in modern flash memories are becoming susceptible to prompt charge loss from ionizing radiation environments found in space. A method for estimating the risk of a charge-loss event is given.

  4. Design and Aero-elastic Simulation of a 5MW Floating Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Vita, Luca; Schmidt Paulsen, Uwe; Aagaard Madsen, Helge; Nielsen, Per Hørlyk; Berthelsen, Petter A.; Cartsensen, Stefan

    This paper deals with the design of a 5MW floating offshore Vertical Axis Wind Turbine (VAWT). The design is based on a new offshore wind turbine concept (DeepWind concept), consisting of a Darrieus rotor mounted on a spar buoy support structure, which is anchored to the sea bed with mooring lines...

  5. A Method for Estimating the Probability of Floating Gate Prompt Charge Loss in a Radiation Environment

    Science.gov (United States)

    Edmonds, L. D.

    2016-01-01

    Since advancing technology has been producing smaller structures in electronic circuits, the floating gates in modern flash memories are becoming susceptible to prompt charge loss from ionizing radiation environments found in space. A method for estimating the risk of a charge-loss event is given.

  6. Quality Improvement: Creating a Float Pool Specialty Within a New Graduate Residency.

    Science.gov (United States)

    Shinners, Jean; Alejandro, John Aldrich N; Frigillana, Vanessa; Desmond, Juliann; LaVigne, Ronda

    2016-01-01

    Creating new norms is essential for success as acute care leaders seek to redesign care delivery. Through the structures of the registered nurse (RN) residency and utilizing a quality improvement process, new graduate RNs demonstrated success in creating a centralized float pool resource. PMID:27323464

  7. 1T Pixel Using Floating-Body MOSFET for CMOS Image Sensors

    OpenAIRE

    Guo-Neng Lu; Arnaud Tournier; François Roy; Benoît Deschamps

    2009-01-01

    We present a single-transistor pixel for CMOS image sensors (CIS). It is a floating-body MOSFET structure, which is used as photo-sensing device and source-follower transistor, and can be controlled to store and evacuate charges. Our investigation into this 1T pixel structure includes modeling to obtain analytical description of conversion gain. Model validation has been done by comparing theoretical predictions and experimental results. On the other hand, the 1T pixel structure has been impl...

  8. Seismic Response of Submerged Floating Tunnel Tether

    Institute of Scientific and Technical Information of China (English)

    SU Zhi-bin; SUN Sheng-nan

    2013-01-01

    A mathematical equation for vibration of submerged floating tunnel tether under the effects of earthquake and parametric excitation is presented.Multi-step Galerkin method is used to simplify this equation and the fourth-order Runge-Kuta integration method is used for numerical analysis.Finally,vibration response of submerged floating tunnel tether subjected to earthquake and parametric excitation is analyzed in a few numerical examples.The results show that the vibration response of tether varies with the seismic wave type; the steady maximum mid-span displacement of tether subjected to seismic wave keeps constant when parametric resonance takes place; the transient maximum mid-span displacement of tether is related to the peak value of input seismic wave acceleration.

  9. Can Oil Float Completely Submerged in Water?

    CERN Document Server

    Nath, Saurabh; Chatterjee, Souvick

    2013-01-01

    Droplet formation in a system of two or more immiscible fluids is a celebrated topic of research in the fluid mechanics community. In this work, we propose an innovative phenomenon where oil when injected drop-wise into a pool of water moves towards the air-water interface where it floats in a fully submerged condition. The configuration, however, is not stable and a slight perturbation to the system causes the droplet to burst and float in partially submerged condition. The droplet contour is analyzed using edge detection. Temporal variation of a characteristic length of the droplet is analyzed using MATLAB image processing. The constraint of small Bond Number established the assumption of lubrication regime in the thin gap. A brief theoretical formulation also showed the temporal variation of the gap thickness

  10. FLOATING DRUG DELIVERY SYSTEM - CHRONOTHERAPEUTIC APPROACH

    Directory of Open Access Journals (Sweden)

    Vishal Kalal

    2011-04-01

    Full Text Available The purpose of writing this review on the floating drug delivery systems (FDDS was to compile the recent literature with special focus on the principal mechanism of floatation to achieve gastric retention. FDDS is one of the approaches in chronotherapeutic drug delivery. In the past reviews of FDDS the physiological and formulation variables affecting gastric retention, approaches to design single-unit and multiple-unit floating systems, their classification and formulation aspects have been covered. This review summarizes the special focus on chronotherapeutics, diseases affected by biological rhythm, its importance, advantages, various approaches in Chronotherapeutic drug delivery and applications of FDDS. These systems are useful for several problems encountered during the development of a pharmaceutical dosage forms.

  11. OCD metrology by floating n/k

    Science.gov (United States)

    Yu, Shinn-Sheng; Huang, Jacky; Ke, Chih-Ming; Gau, Tsai-Sheng; Lin, Burn J.; Yen, Anthony; Lane, Lawrence; Vuong, Vi; Chen, Yan

    2007-03-01

    In this paper, one of the major contributions to the OCD metrology error, resulting from within-wafer variation of the refractive index/extinction coefficient (n/k) of the substrate, is identified and quantified. To meet the required metrology accuracy for the 65-nm node and beyond, it is suggested that n/k should be floating when performing the regression for OCD modeling. A feasible way of performing such regression is proposed and verified. As shown in the presented example, the measured CDU (3σ) with n/k fixed and n/k floating is 1.94 nm and 1.42 nm, respectively. That is, the metrology error of CDU committed by assuming n/k fixed is more than 35% of the total CDU.

  12. Capping soft tailings from a floating platform

    Energy Technology Data Exchange (ETDEWEB)

    Costello, M.; Van Kesteren, W.; Hedblom, E. [Alberta Univ., Edmonton, AB (Canada). Oil Sands Tailings Research Facility

    2010-07-01

    This PowerPoint presentation discussed methods of capping oil sands soft tailings from a floating platform. Caps on soft sediments at various locations throughout the world were analyzed in order to determine their water content and surface shear strength. A small-scale raining project was conducted at Stryker Bay to cap tailings with 150,000 m{sup 3} of sand. A small-scale rainbowing project at Soda Lake delivered sand at a rate of between 20 to 60 m{sup 3}/hr. A large-scale rainbowing project in Rotterdam delivered 2000 m{sup 3}/hr of sand. The capping and dredging project cost $12 per m{sup 3}. Case studies of various capping projects were presented in order to describe and demonstrate the floating platform technique as well as the installation of wicks and drains. The method can be used to cap very soft tailings with thin, uniform lifts. tabs., figs.

  13. Relative Wages in Monetary Union and Floating

    OpenAIRE

    Vartiainen, Juhana

    1999-01-01

    We analyse a small open economy with a tradable and a sheltered sector. If the unions that operate in each sector coordinate their wage demands sectorwise, the choice of monetary regime - floating cum inflation target vs EMU - may affect the relative wages and prices of the economy. We show that EMU results in lower prices for tradable goods and lower real wages in the traded sector while opposite results hold for sheltered sector prices and wages. Thus, if large unions behave strategically, ...

  14. Restoration of streams used for timber floating

    OpenAIRE

    Palm, Daniel

    2007-01-01

    The construction of floatways during the 19th and 20th century profoundly changed the habitat conditions for fish and other aquatic organisms in lotic environments. Increased mortality during early life stages, reduced habitat quality and availability probably had large negative consequences for populations of salmonids. As timber floating ended during the 1970’s, restoration programs were initiated that aimed to reverse the damage caused by floatway activities and to increase the production ...

  15. Sonar location system for freely floating buoys

    Science.gov (United States)

    Bird, I. G.

    1983-05-01

    A rf interrogated sonar location system for freely floating buoys is described. The location of an array of up to three buoys may be determined on an almost continuous basis within a radius of 500 m from a shipboard monitoring station. Location accuracy of typically ±0.5 m at 200-m range, low cost, and ease of operation are the major features of the system.

  16. Coupled Mooring Systems for Floating Wind Farms

    OpenAIRE

    Goldschmidt, Marek

    2014-01-01

    In this work the feasibility of an integrated catenary loose mooring system for offshore floating wind turbines is investigated. The dynamic behavior of different wind farm layouts is analyzed employing the equation of motion. It will be especially sought after potential resonance problems. The equation is solved in frequency domain, using a linearized stiffness matrix, as well as in time domain. Time-domain simulation is done by using a quasi-static model, where the catenary equa...

  17. A census of Meddies tracked by floats

    OpenAIRE

    Richardson, P.L.; Bower, A.S.; Zenk, Walter

    2000-01-01

    Recent subsurface float measurements in 27 Mediterranean Water eddies (Meddies) in the Atlantic are grouped together to reveal new information about the pathways of these energetic eddies and how they are often modified and possibly destroyed by collisions with seamounts. Twenty Meddles were tracked in the Iberian Basin west of Portugal, seven in the Canary Basin. During February 1994 14 Meddles were simultaneously observed, 11 of them in the Iberian Basin. Most (69%) of the newly formed Medd...

  18. Improved bioavailability through floating microspheres of lovastatin

    OpenAIRE

    Kumar, S.; K Nagpal; Singh SK; DN Mishra

    2011-01-01

    "n Background and the purpose of the study: Lovastatin is an antihyperlipidemic agent which has low bioavailability due to the extensive first pass metabolism. It was sought to increase gastric retention of lovastatin by development of a sustained release gastroretentive drug delivery system leading to reduced fluctuation in the plasma concentration and improved bioavailability. "nMethods: Floating microspheres were prepared by emulsion solvent diffusion technique, using va...

  19. Evaluation of A "Floating" Aerobics Floor

    OpenAIRE

    Favor, Craig M.

    1997-01-01

    Aerobics dance floors often produce annoying floor vibrations in adjacent parts of a building due to the rhythmic impact of the aerobicists. Various types of shock absorbing aerobics and dance floors are widely used to prevent injuries to the participants, but the floors may not prevent vibrations in adjacent areas of the building. The purpose of this investigation is to evaluate a temporary "floating" concrete a...

  20. Collector floating potentials in a discharge plasma

    International Nuclear Information System (INIS)

    We present the results of a study on electrode floating potential formation in a hot-cathode discharge plasma. The electron component of the plasma is composed from two populations. The high temperature component develops from primary electrons and the cool component from secondary electrons born by ionisation of cold neutral gas. A static, kinetic plasma-sheath model is use to calculate the pre-sheath potential and the floating potential of the electrode. For hot primary electrons a truncated Maxwellian distribution is assumed. The plasma system is also modelled numerically with a dynamic, electrostatic particle simulation. The plasma source injects temporally equal fluxes of ions and electrons with half-Maxwellian velocities. Again, the hot electron distribution is truncated in the high velocity tail. The plasma parameters, such as ion temperature and mass, electron temperatures, discharge voltages, etc. correspond to experimental values. The experimental measurements of the electrode floating potential are performed in weakly magnetised plasma produced with hot cathode discharge in argon gas. Theoretical, simulation and experimental results are compared and they agree very well.(author)

  1. Floating Oil-Spill Containment Device

    Science.gov (United States)

    Jones, Jack A.

    2012-01-01

    Previous oil containment booms have an open top that allows natural gas to escape, and have significant oil leakage due to wave action. Also, a subsea pyramid oil trap exists, but cannot move relative to moving oil plumes from deepsea oil leaks. The solution is to have large, moveable oil traps. One version floats on the sea surface and has a flexible tarp cover and a lower weighted skirt to completely entrap the floating oil and natural gas. The device must have at least three sides with boats pulling at each apex, and sonar or other system to track the slowly moving oil plume, so that the boats can properly locate the booms. The oil trap device must also have a means for removal of the oil and the natural gas. A second design version has a flexible pyramid cover that is attached by lines to ballast on the ocean floor. This is similar to fixed, metal pyramid oil capture devices in the Santa Barbara Channel off the coast of California. The ballast lines for the improved design, however, would have winches that can move the pyramid to always be located above the oil and gas plume. A third design is a combination of the first two. It uses a submerged pyramid to trap oil, but has no anchor and uses boats to locate the trap. It has ballast weights located along the bottom of the tarp and/or at the corners of the trap. The improved floating oil-spill containment device has a large floating boom and weighted skirt surrounding the oil and gas entrapment area. The device is triangular (or more than three sides) and has a flexible tarp cover with a raised gas vent area. Boats pull on the apex of the triangles to maintain tension and to allow the device to move to optimum locations to trap oil and gas. The gas is retrieved from a higher buoyant part of the tarp, and oil is retrieved from the floating oil layer contained in the device. These devices can be operated in relatively severe weather, since waves will break over the devices without causing oil leaking. Also, natural

  2. To Float or Not to Float: How Interactions between Light and Dissolved Inorganic Carbon Species Determine the Buoyancy of Stratiotes aloides

    OpenAIRE

    Harpenslager, S.F.; Smolders, A.J.P.; Kieskamp, A.A.M.; Roelofs, J.G.M.; Lamers, L.P.M.

    2015-01-01

    Structural diversity formed by dense, floating Stratiotes aloides stands, generates hotspots of biodiversity of flora and fauna in wetlands. However, only part of the populations become emergent and provide this important facilitation. Since it has been hypothesised that its buoyancy depends on the rates of underwater photosynthesis, we investigated the role of dissolved CO2 availability and PAR on photosynthesis, biomass production and buoyancy in a controlled greenhouse experiment. Photosyn...

  3. The Development of Submerged Floating Tunnels as an innovative solution for waterway crossings

    OpenAIRE

    Martire, Giulio

    2010-01-01

    The present Thesis is organized in 10 chapters. In particular Chapter 1 gives a general overview of the modern solutions and technologies available in the field of waterway crossings, introducing briefly the revolutionary concept of Submerged Floating Tunnel. Chapter 2 provides a deeper insight into the main characteristics of this innovative structural solution for waterway crossings: first its structural features are described and the relevant loading conditions disc...

  4. FPGA Based Quadruple Precision Floating Point Arithmetic for Scientific Computations

    OpenAIRE

    Mamidi Nagaraju; Geedimatla Shekar

    2012-01-01

    In this project we explore the capability and flexibility of FPGA solutions in a sense to accelerate scientific computing applications which require very high precision arithmetic, based on IEEE 754 standard 128-bit floating-point number representations. Field Programmable Gate Arrays (FPGA) is increasingly being used to design high end computationally intense microprocessors capable of handling floating point mathematical operations. Quadruple Precision Floating-Point Arithmetic is important...

  5. DEVELOPMENT AND OPTIMIZATION OF FLOATING MICROSPHERES OF GLICLAZIDE

    OpenAIRE

    Shardendu Prakash; Akanksha Bhandari; Raghav Mishra; Pramod Kumar Sharma

    2015-01-01

    The objective of the present study was to develop floating microspheres of Gliclazide in order to achieve an extended retention in the upper gastrointestinal tract, which may result in enhanced absorption and thereby improved bioavailability. The present study involves preparation and evaluation of floating microspheres using Gliclazide as a model drug for prolongation of the gastric retention time. As gliclazide is mainly absorbed from stomach, thus using floating microspheres as a mode o...

  6. Reduced model design of a floating wind turbine

    OpenAIRE

    Sandner, Frank

    2012-01-01

    Floating platform concepts offer the prospect of harvesting offshore wind energy at deep water locations for countries with a limited number of suitable shal- low water locations for bottom-mounted offshore wind turbines. The floating spar-buoy concept has shown promising experimental and theoretical results. Al- though various codes for a detailed simulation exist the purpose of this work is to elaborate a reduced Floating Offshore Wind Turbine (FOWT) model that mainly reproduces the overall...

  7. Formulation and evaluation of glipizide floating-bioadhesive tablets

    OpenAIRE

    Patel, Jayvadan K.; Jayant R. Chavda

    2010-01-01

    The purpose of this study was formulation and in vitro evaluation of floating-bioadhesive tablets to lengthen the stay of glipizide in its absorption area. Effervescent tablets were made using chitosan (CH), hydroxypropyl methylcellulose (HPMC), carbopolP934 (CP), polymethacrylic acid (PMA), citric acid, and sodium bicarbonate. Tablets with 5% effervescent base had longer lag time than 10%. The type of polymer had no significant effect on the floating lag time. All tablets floated atop the me...

  8. Formulation and Evaluation of Floating Drug Delivery System of Aceclofenac

    OpenAIRE

    SENGODAN TAMIZHARASI; T. Sivakumar; RATHI JAGDISH CHANDRA

    2011-01-01

    A sustained release system for aceclofenac designed to increase its residence time in the stomach without contact with the mucosa was achieved through the preparation of floating microspheres by the emulsion solvent diffusion technique. Floating microspheres were prepared using either Eudragit S 100 (ES) alone or with Eudragit RL 100 in different ratios. All formulation show good flow properties. The floating microspheres were found to be spherical by SEM. FT-IR study confirmed the drug-polym...

  9. Influence of artificial ecological floating beds on river hydraulic characteristics

    Institute of Scientific and Technical Information of China (English)

    饶磊; 钱进; 敖燕辉

    2014-01-01

    The artificial ecological floating bed is widely used in rivers and lakes to repair and purify polluted water. However, the water flow pattern and the water level distribution are significantly changed by the floating beds, and the influence on the water flow is different from that of aquatic plants. In this paper, based on the continuous porous media model, a moveable two-layer combination model is built to describe the floating bed. The influences of the floating beds on the water flow characteristics are studied by numerical simulations and experiments using an experimental water channel. The variations of the water level distribution are discussed under conditions of different flow velocities ( v=0.1 m/s, 0.2 m/s, 0.30 m/s, 0.4 m/s), floating bed coverage rates (20%, 40%, 60%) and arrangement positions away from the channel wall ( D=0 m, 0.1 m, 0.2 m). The results indicate that the flow velocity increases under the floating beds, and the water level rises significantly under high flow velocity conditions in the upstream region and the floating bed region. In addition, the average rising water level value (ARWLV) increases significantly with the increase of the floating bed coverage rate, and the arrangement position of floating beds in the river can also greatly influence the water level distribution under a high-flow velocity condition (v³0.2 m/s) .

  10. Design and Implementation of Complex Floating Point Processor Using FPGA

    Directory of Open Access Journals (Sweden)

    Murali Krishna Pavuluri

    2013-10-01

    Full Text Available This paper presents complete processor hardware wit h three arithmetic units. The first arithmetic unit can perform 32-bit integer arithmetic operations. The s econd unit can perform arithmetic operations such a s addition, subtraction, multiplication, division, an d square root on 32-bit floating point numbers. The third unit can perform arithmetic operations such as addi tion, subtraction, multiplication on complex number s. The specific advancement in this processor is the n ew architecture introduced for complex arithmetic u nit. In general complex floating point arithmetic hardwa re consists of floating to fixed and fixed to float ing conversions. But using such hardware will lead to c ompromise between accuracy and number of bits used to represent the fixed point equivalent of floating point numbers. The proposed architecture avoids th at compromise and it is implemented with less number o f look-up tables to save around 5500 logic gates. T he complex numbers are represented using a subset of I EEE754 standard floating point format, 16-bits for real part and 16-bits for imaginary part. The float ing point arithmetic unit works on 32-bit IEEE754 s ingle precision numbers. The instruction set is specially designed to support integer, floating point and co mplex floating point arithmetic operations. The on-chip R AM is 8kBytes and is extendable up to 64kBytes. As the processor is designed to implement on FPGA, the emb edded block RAMs are utilized as RAM.

  11. A numerical framework for modelling floating wind turbines

    Science.gov (United States)

    Vire, Axelle; Xiang, Jiansheng; Piggott, Matthew; Latham, John-Paul; Pain, Christopher

    2012-11-01

    This work couples a fluid/ocean- and a solid- dynamics model in order to numerically study fluid-structure interactions. The fully non-linear Navier-Stokes and solid-dynamics equations are solved on two distinct finite-element and unstructured grids. The interplay between fluid and solid is represented through a penalty force in the momentum balances of each material. The present algorithm is novel in that it spatially conserves the discrete penalty force, when exchanging it between both models, independently of the mesh resolution and of the shape-function orders in each model. This numerical framework targets the modelling of offshore floating wind turbines. Results will be shown for the flow past a moving pile and an actuator-disk representation of a turbine. This research is supported by the European Union Seventh Framework Programme (grant agreement PIEF-GA-2010-272437).

  12. Wind/Wave Misalignment in the Loads Analysis of a Floating Offshore Wind Turbine: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Barj, L.; Stewart, S.; Stewart, G.; Lackner, M.; Jonkman, J.; Robertson, A.

    2014-02-01

    Wind resources far from the shore and in deeper seas have encouraged the offshore wind industry to look into floating platforms. The International Electrotechnical Commission (IEC) is developing a new technical specification for the design of floating offshore wind turbines that extends existing design standards for land-based and fixed-bottom offshore wind turbines. The work summarized in this paper supports the development of best practices and simulation requirements in the loads analysis of floating offshore wind turbines by examining the impact of wind/wave misalignment on the system loads under normal operation. Simulations of the OC3-Hywind floating offshore wind turbine system under a wide range of wind speeds, significant wave heights, peak-spectral periods and wind/wave misalignments have been carried out with the aero-servo-hydro-elastic tool FAST [4]. The extreme and fatigue loads have been calculated for all the simulations. The extreme and fatigue loading as a function of wind/wave misalignment have been represented as load roses and a directional binning sensitivity study has been carried out. This study focused on identifying the number and type of wind/wave misalignment simulations needed to accurately capture the extreme and fatigue loads of the system in all possible metocean conditions considered, and for a down-selected set identified as the generic US East Coast site. For this axisymmetric platform, perpendicular wind and waves play an important role in the support structure and including these cases in the design loads analysis can improve the estimation of extreme and fatigue loads. However, most structural locations see their highest extreme and fatigue loads with aligned wind and waves. These results are specific to the spar type platform, but it is expected that the results presented here will be similar to other floating platforms.

  13. Floating nuclear power - Desalination complex using a nuclear power plant of the KLT-40 type and the reverse osmosis process

    International Nuclear Information System (INIS)

    A nuclear power plant of the KLT-40 type, which meets international safety requirements, is proposed as the power source for the floating nuclear power plant. The main advantages of the nuclear power-desalination complex are as follows: (1) the established fabrication technology, and the confirmed long term reliability and service life of KLT-40 type nuclear power plants and desalination facilities; (2) the high quality of fabrication at the shipbuilding plant, and the possibility of handover of the complex to the customer on a turnkey basis within the shortest possible time; (3) the possibility of siting in various coastal regions of the world; and (4) ease of maintenance by a special service ship at the mooring place, and simple. decommissioning by towing to the supplier country. The floating nuclear power-desalination station for producing potable water is a special non-self-propelled ship equipped with a twin unit nuclear power plant of the KLT-40 type intended for sea water desalination in a protected water area, together with service facilities at the plant mooring place. Distillation-desalination plants with film type, horizontal tube evaporators are used in the floating station for thermal desalination. The floating nuclear power station (FNPS) is a special non-self-propelled ship intended for power generation in a protected water area. The station includes two nuclear steam supply systems of the KLT-40 type, a steam turbine plant, a power plant, and servicing and shipboard systems. The floating nuclear dual purpose station for co-generating electricity and potable water using the reverse osmosis (RO) process includes two floating structures: the FNPS and a ship for producing potable water from sea water using RO. The organizational structure for the development and operation of the floating nuclear power-desalination complex has been studied

  14. Design of crossed-mirror array to form floating 3D LED signs

    Science.gov (United States)

    Yamamoto, Hirotsugu; Bando, Hiroki; Kujime, Ryousuke; Suyama, Shiro

    2012-03-01

    3D representation of digital signage improves its significance and rapid notification of important points. Our goal is to realize floating 3D LED signs. The problem is there is no sufficient device to form floating 3D images from LEDs. LED lamp size is around 1 cm including wiring and substrates. Such large pitch increases display size and sometimes spoils image quality. The purpose of this paper is to develop optical device to meet the three requirements and to demonstrate floating 3D arrays of LEDs. We analytically investigate image formation by a crossed mirror structure with aerial aperture, called CMA (crossed-mirror array). CMA contains dihedral corner reflectors at each aperture. After double reflection, light rays emitted from an LED will converge into the corresponding image point. We have fabricated CMA for 3D array of LEDs. One CMA unit contains 20 x 20 apertures that are located diagonally. Floating image of LEDs was formed in wide range of incident angle. The image size of focused beam agreed to the apparent aperture size. When LEDs were located three-dimensionally (LEDs in three depths), the focused distances were the same as the distance between the real LED and the CMA.

  15. Motion performance and mooring system of a floating offshore wind turbine

    Science.gov (United States)

    Zhao, Jing; Zhang, Liang; Wu, Haitao

    2012-09-01

    The development of offshore wind farms was originally carried out in shallow water areas with fixed (seabed mounted) structures. However, countries with limited shallow water areas require innovative floating platforms to deploy wind turbines offshore in order to harness wind energy to generate electricity in deep seas. The performances of motion and mooring system dynamics are vital to designing a cost effective and durable floating platform. This paper describes a numerical model to simulate dynamic behavior of a new semi-submersible type floating offshore wind turbine (FOWT) system. The wind turbine was modeled as a wind block with a certain thrust coefficient, and the hydrodynamics and mooring system dynamics of the platform were calculated by SESAM software. The effect of change in environmental conditions on the dynamic response of the system under wave and wind loading was examined. The results indicate that the semi-submersible concept has excellent performance and SESAM could be an effective tool for floating wind turbine design and analysis.

  16. Motion Performance and Mooring System of a Floating Offshore Wind Turbine

    Institute of Scientific and Technical Information of China (English)

    Jing Zhao; Liang Zhang; Haitao Wu

    2012-01-01

    The development of offshore wind farms was originally carried out in shallow water areas with fixed (seabed mounted) structures.However,countries with limited shallow water areas require innovative floating platforms to deploy wind turbines offshore in order to harness wind energy to generate electricity in deep seas.The performances of motion and mooring system dynamics are vital to designing a cost effective and durable floating platform.This paper describes a numerical model to simulate dynamic behavior of a new semi-submersible type floating offshore wind turbine (FOWT) system.The wind turbine was modeled as a wind block with a certain thrust coefficient,and the hydrodynamics and mooring system dynamics of the platform were calculated by SESAM software.The effect of change in environmental conditions on the dynamic response of the system under wave and wind loading was examined.The results indicate that the semi-submersible concept has excellent performance and SESAM could be an effective tool for floating wind turbine design and analysis.

  17. Development and in vivo floating behavior of verapamil HCl intragastric floating tablets.

    Science.gov (United States)

    Patel, Anand; Modasiya, Moin; Shah, Dushyant; Patel, Vishnu

    2009-01-01

    A novel gastro retentive controlled release drug delivery system of verapamil HCl was formulated in an effort to increase the gastric retention time of the dosage form and to control drug release. Hydroxypropylmethylcellulose (HPMC), carbopol, and xanthan gum were incorporated for gel-forming properties. Buoyancy was achieved by adding an effervescent mixture of sodium bicarbonate and anhydrous citric acid. In vitro drug release studies were performed, and drug release kinetics was evaluated using the linear regression method. The optimized intragastric floating tablet composed of 3:2 of HPMC K4M to xanthan gum exhibited 95.39% drug release in 24 h in vitro, while the buoyancy lag time was 36.2 s, and the intragastric floating tablet remained buoyant for >24 h. Zero-order and non-Fickian release transport was confirmed as the drug release mechanism from the optimized formulation (F7). X-ray studies showed that total buoyancy time was able to delay the gastric emptying of verapamil HCl intragastric floating tablet in mongrel dogs for more than 4 h. Optimized intragastric floating tablet showed no significant change in physical appearance, drug content, total buoyancy time, or in vitro dissolution pattern after storage at 40 degrees C/75% relative humidity for 3 months. PMID:19296224

  18. FLOATING CRANE RESPONSE IN SEA WAVES

    OpenAIRE

    Čorić, Većeslav; Ćatipović, Ivan; Slapničar, Vedran

    2014-01-01

    Many activities present in the offshore technology are affected by sea waves and their safety strongly depends on the sea state. The fundamental question in operation risk analysis is the limit sea state which enables the safe operation controlled in all phases: from the sea surface to the sea bottom. The safe limit sea state is especially important when some lifting operation is performed in sea waves. This paper presents a dynamical model of a floating crane in sea waves with a hanging load...

  19. The floating desalination complex GEYSER-1

    International Nuclear Information System (INIS)

    A conventional floating desalination complex, GEYSER-1, is presented which is capable of producing 40,000 cubic meters per day (m3/d) of fresh water from brackish water or seawater. The complex includes a water intake system, a preliminary water preparation system, a high-pressure pump house and a power installation based on diesel or a gas turbines with service equipment. GEYSER-1 can be transported to the place of operation either by a heavy lift ship or by towing. (author)

  20. Explicit free‐floating beam element

    DEFF Research Database (Denmark)

    Nielsen, Martin Bjerre; Krenk, Steen

    2014-01-01

    A two‐node free‐floating beam element capable of undergoing arbitrary large displacements and finite rotations is presented in explicit form. The configuration of the beam in three‐dimensional space is represented by the global components of the position of the beam nodes and an associated set of...... interpolation of kinematic variables, resulting in a locking‐free formulation in terms of three explicit matrices. A set of classic benchmark examples illustrates excellent performance of the explicit beam element. Copyright © 2014 John Wiley & Sons, Ltd....

  1. Floating air riding seal for a turbine

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, Todd A

    2016-08-16

    A floating air riding seal for a gas turbine engine with a rotor and a stator, an annular piston chamber with an axial moveable annular piston assembly within the annular piston chamber formed in the stator, an annular cavity formed on the annular piston assembly that faces a seal surface on the rotor, where the axial moveable annular piston includes an inlet scoop on a side opposite to the annular cavity that scoops up the swirling cooling air and directs the cooling air to the annular cavity to form an air cushion with the seal surface of the rotor.

  2. Accelerating MicroBlaze Floating Point Operations

    Czech Academy of Sciences Publication Activity Database

    Kadlec, Jiří; Bartosinski, Roman; Daněk, Martin

    Delft : IEEE, 2007 - (Bertels, K.; Najjar, W.; Genderen, A.; Vassiliadis, S.), s. 621-624 ISBN 978-1-4244-1059-0; ISBN 1-4244-1060-6. [International Conference on Field Programmable Logic and Applications. FPL 2007. Amsterdam (NL), 27.08.2007-29.08.2007] R&D Projects: GA AV ČR 1ET400750406; GA MŠk(CZ) 1M0567 EU Projects: European Commission(XE) 027611 - AETHER Institutional research plan: CEZ:AV0Z10750506 Keywords : acceleration * floating point operation * coprocessor * MicroBlaze Subject RIV: JC - Computer Hardware ; Software

  3. 40 CFR 426.50 - Applicability; description of the float glass manufacturing subcategory.

    Science.gov (United States)

    2010-07-01

    ... float glass manufacturing subcategory. 426.50 Section 426.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Float Glass Manufacturing Subcategory § 426.50 Applicability; description of the float...

  4. Extended onshore control of a floating wind turbine with wave disturbance reduction

    DEFF Research Database (Denmark)

    Christiansen, S.; Knudsen, T.; Bak, Thomas

    2014-01-01

    Reaching for higher wind resources floating wind turbines are being investigated. Wave induced loads significantly increase for floating wind turbines, and applying conventional onshore control strategies to floating wind turbines has been shown to impose negative damped oscillations in fore...

  5. Evaporation mitigation using floating modular devices

    Science.gov (United States)

    Hassan, M. Mahmudul; Peirson, William Leslie; Neyland, Bryce M.; Fiddis, Nicholas McQuistan

    2015-11-01

    Reducing evaporation losses from open water storages is of paramount importance in the improvement of water security in arid countries, including Australia. Widespread adoption of evaporation mitigation techniques has been prevented by their high capital and maintenance or operating costs. The use of clean, floating recycled materials to mitigate evaporation technique has been investigated systematically at sites within both the coastal and semi-arid zones of Australia. Evaporation reduction systematically increases with the proportion of covered surface. Evaporation is reduced by 43% at coastal site and 37% at arid zone site at the maximum packing densities achievable for a single layer of floating devices. The study highlights the importance of both long-term investigations and the climatic influences in the robust quantification of evaporation mitigation. The effects of solar radiation, temperature, wind speed and relative humidity on the evaporation rate at both study sites have been determined in terms of both the classical Penman model and FAO Penman Monteith model with corresponding pan coefficients quantified. FAO Penman Monteith model better estimates evaporation from the open reference tank.

  6. High-Rate Capable Floating Strip Micromegas

    CERN Document Server

    Bortfeldt, Jonathan; Biebel, Otmar; Danger, Helge; Flierl, Bernhard; Hertenberger, Ralf; Lösel, Philipp; Moll, Samuel; Parodi, Katia; Rinaldi, Ilaria; Ruschke, Alexander; Zibell, André

    2015-01-01

    We report on the optimization of discharge insensitive floating strip Micromegas (MICRO-MEsh GASeous) detectors, fit for use in high-energy muon spectrometers. The suitability of these detectors for particle tracking is shown in high-background environments and at very high particle fluxes up to 60MHz/cm$^2$. Measurement and simulation of the microscopic discharge behavior have demonstrated the excellent discharge tolerance. A floating strip Micromegas with an active area of 48cm$\\times$50cm with 1920 copper anode strips exhibits in 120GeV pion beams a spatial resolution of 50$\\mu$m at detection efficiencies above 95%. Pulse height, spatial resolution and detection efficiency are homogeneous over the detector. Reconstruction of particle track inclination in a single detector plane is discussed, optimum angular resolutions below $5^\\circ$ are observed. Systematic deviations of this $\\mu$TPC-method are fully understood. The reconstruction capabilities for minimum ionizing muons are investigated in a 6.4cm$\\time...

  7. Treatment of Floating Knee Injury in Children

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The necessity and superiority of the surgical operation on children with floating knee injury and the fracture union and complications were investigated. Twenty-eight children with floating knee injury were subjected to open reduction and internal fixation or external fixator. The patients were followed up for 18 months to 7 years. The curative effectiveness was scored by Karlstrom criteria. The results showed that no nonunion or deformity was found. The affected limb was 1.2 cm to 1.5 cm longer in 2 cases, 0.8 to 1.2 cm shorter in 3 cases than the contralateral. No severe dysfunction of knee joint occurred. The excellent-good rate was 92.8 % and the curative rate 71.4 % respectively. So for children whose age is older than 5 years, it's a good way to treat the fractures of femur and tibia with open reduction and internal fixation or external fixator. The method can be advantageous for the nursing care, early function recovery, shortening of the hospital stay and avoidance of severe complications.

  8. Floating treatment wetlands for domestic wastewater treatment.

    Science.gov (United States)

    Faulwetter, J L; Burr, M D; Cunningham, A B; Stewart, F M; Camper, A K; Stein, O R

    2011-01-01

    Floating islands are a form of treatment wetland characterized by a mat of synthetic matrix at the water surface into which macrophytes can be planted and through which water passes. We evaluated two matrix materials for treating domestic wastewater, recycled plastic and recycled carpet fibers, for chemical oxygen demand (COD) and nitrogen removal. These materials were compared to pea gravel or open water (control). Experiments were conducted in laboratory scale columns fed with synthetic wastewater containing COD, organic and inorganic nitrogen, and mineral salts. Columns were unplanted, naturally inoculated, and operated in batch mode with continuous recirculation and aeration. COD was efficiently removed in all systems examined (>90% removal). Ammonia was efficiently removed by nitrification. Removal of total dissolved N was ∼50% by day 28, by which time most remaining nitrogen was present as NO(3)-N. Complete removal of NO(3)-N by denitrification was accomplished by dosing columns with molasses. Microbial communities of interest were visualized with denaturing gradient gel electrophoresis (DGGE) by targeting specific functional genes. Shifts in the denitrifying community were observed post-molasses addition, when nitrate levels decreased. The conditioning time for reliable nitrification was determined to be approximately three months. These results suggest that floating treatment wetlands are a viable alternative for domestic wastewater treatment. PMID:22105133

  9. Externalities, Floating Population and Spatial Agglomeration

    Institute of Scientific and Technical Information of China (English)

    Du Yu; Wang Chuansheng; Fan Jie

    2007-01-01

    With the further development of socialist market economy,the mobility of factor markets in China,especially the labor market.is strengthened.Extemalities interacts with the agglomeration of productive factors.Under the framework of new economic geographg this article presents a theoretical model involving the endogenous population density affected by urban externalities.Results show that the population density is more concentrated around the center because the degree and extent of interaction between individuals intensifies when the distance from the center decreases.When there are several extemalifies resonurces,the aggregation of externalities changes the configuration of spatial factor allocation.These results fit well with the empirical facts about the decreasing density of floating population along the cities of Guangzhou,Dongguan and Shenzhen in Guangdong Province which is situat d in the eastern coast of the Pearl River Delta.We find that under the impacts of externalities released from Hong Kong into the coast,floating population Was more concentrated around Shenzhen and Dongguan,which are more adjacent to Hong Kong compared with Guangzhou City.

  10. Improved bioavailability through floating microspheres of lovastatin

    Directory of Open Access Journals (Sweden)

    S Kumar

    2011-03-01

    Full Text Available "n Background and the purpose of the study: Lovastatin is an antihyperlipidemic agent which has low bioavailability due to the extensive first pass metabolism. It was sought to increase gastric retention of lovastatin by development of a sustained release gastroretentive drug delivery system leading to reduced fluctuation in the plasma concentration and improved bioavailability. "nMethods: Floating microspheres were prepared by emulsion solvent diffusion technique, using various polymers and their blends. The in vitro performance was evaluated for drug-polymer compatibility, percent yield, particle size, drug entrapment efficiency, in vitro onset and duration of floatation, in vitro drug release as well as in vivo determination of serum cholesterol level. "nResults: The mean particle size of microspheres was observed to be between 6.9 to 9.5 μm and the maximum particle size was around 50 μm. In vivo studies of the selected batches indicated lower level of serum cholesterol compared to the marketed tablet at the same dose but was not significant. Major conclusion: The data obtained in this study suggested that a microparticulate floating dosage form of lovastatin can be successfully designed to yield controlled delivery with improved therapeutic efficacy.

  11. 46 CFR 131.870 - Life floats and buoyant apparatus.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Life floats and buoyant apparatus. 131.870 Section 131.870 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats and buoyant apparatus. (a) The name of the vessel must be plainly...

  12. FPGA Based Quadruple Precision Floating Point Arithmetic for Scientific Computations

    Directory of Open Access Journals (Sweden)

    Mamidi Nagaraju

    2012-09-01

    Full Text Available In this project we explore the capability and flexibility of FPGA solutions in a sense to accelerate scientific computing applications which require very high precision arithmetic, based on IEEE 754 standard 128-bit floating-point number representations. Field Programmable Gate Arrays (FPGA is increasingly being used to design high end computationally intense microprocessors capable of handling floating point mathematical operations. Quadruple Precision Floating-Point Arithmetic is important in computational fluid dynamics and physical modelling, which require accurate numerical computations. However, modern computers perform binary arithmetic, which has flaws in representing and rounding the numbers. As the demand for quadruple precision floating point arithmetic is predicted to grow, the IEEE 754 Standard for Floating-Point Arithmetic includes specifications for quadruple precision floating point arithmetic. We implement quadruple precision floating point arithmetic unit for all the common operations, i.e. addition, subtraction, multiplication and division. While previous work has considered circuits for low precision floating-point formats, we consider the implementation of 128-bit quadruple precision circuits. The project will provide arithmetic operation, simulation result, hardware design, Input via PS/2 Keyboard interface and results displayed on LCD using Xilinx virtex5 (XC5VLX110TFF1136 FPGA device.

  13. 40 CFR 63.1043 - Standards-Separator floating roof.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Standards-Separator floating roof. 63...) National Emission Standards for Oil-Water Separators and Organic-Water Separators § 63.1043 Standards—Separator floating roof. (a) This section applies to owners and operators subject to this subpart...

  14. The effects of second-order hydrodynamics on a semisubmersible floating offshore wind turbine

    Science.gov (United States)

    Bayati, I.; Jonkman, J.; Robertson, A.; Platt, A.

    2014-06-01

    The objective of this paper is to assess the second-order hydrodynamic effects on a semisubmersible floating offshore wind turbine. Second-order hydrodynamics induce loads and motions at the sum- and difference-frequencies of the incident waves. These effects have often been ignored in offshore wind analysis, under the assumption that they are significantly smaller than first-order effects. The sum- and difference-frequency loads can, however, excite eigenfrequencies of a floating system, leading to large oscillations that strain the mooring system or vibrations that cause fatigue damage to the structure. Observations of supposed second-order responses in wave-tank tests performed by the DeepCwind consortium at the Maritime Research Institute Netherlands (MARIN) offshore basin suggest that these effects might be more important than originally expected. These observations inspired interest in investigating how second-order excitation affects floating offshore wind turbines and whether second-order hydrodynamics should be included in offshore wind simulation tools like FAST. In this work, the effects of second-order hydrodynamics on a floating semisubmersible offshore wind turbine are investigated. Because FAST is currently unable to account for second-order effects, a method to assess these effects was applied in which linearized properties of the floating wind system derived from FAST (including the 6x6 mass and stiffness matrices) are used by WAMIT to solve the first- and second-order hydrodynamics problems in the frequency domain. The method was applied to the Offshore Code Comparison Collaboration Continuation OC4-DeepCwind semisubmersible platform, supporting the National Renewable Energy Laboratory's 5-MW baseline wind turbine. In this paper, the loads and response of the system caused by the second-order hydrodynamics are analysed and compared to the first-order hydrodynamic loads and induced motions in the frequency domain. Further, the second-order loads

  15. Model-based control of a ballast-stabilized floating wind turbine exposed to wind and waves

    Energy Technology Data Exchange (ETDEWEB)

    Christiansen, Soeren

    2013-01-15

    The wind turbine is a commercial product which is competing against other sources of energy, such as coal and gas. This competition drives a constant development to reduce costs and improve efficiency in order to reduce the total cost of the energy. The latest offshore development is the floating wind turbine, for water depths beyond 50 meters where winds are stronger and less turbulent. A floating wind turbine is subject to not only aerodynamics and wind induced loads, but also to hydrodynamics and wave induced loads. In contrast to a bottom fixed wind turbine, the floating structure, the hydrodynamics and the loads change the dynamic behavior of a floating wind turbine. Consequently, conventional wind turbine control cause instabilities on floating wind turbines. This work addresses the control of a floating spar buoy wind turbine, and focuses on the impact of the additional platform dynamics. A time varying control model is presented based on the wind speed and wave frequency. Estimates of the wind speed and wave frequency are used as scheduling variables in a gain scheduled linear quadratic controller to improve the electrical power production while reducing fatigue. To address the problem of negative damped fore-aft tower motion, additional control loops are suggested which stabilize the response of the onshore controller and reduce the impact of the wave induced loads. This research is then extended to model predictive control, to further address wave disturbances. In the context of control engineering, the dynamics and disturbances of a floating wind turbine have been identified and modeled. The objectives of maximizing the production of electrical power and minimizing fatigue have been reached by using advanced methods of estimation and control. (Author)

  16. Electrowetting in a water droplet with a movable floating substrate

    Science.gov (United States)

    Shahzad, Amir; Masud, A. R.; Song, Jang-Kun

    2016-05-01

    Electrowetting (EW) enables facile manipulation of a liquid droplet on a hydrophobic surface. In this study, manipulation of an electrolyte droplet having a small floating object on it was investigated on a solid hydrophobic substrate under the EW process. Herein, the floating object exhibited a vertical motion under an applied electric field owing to the spreading and contraction of the droplet on its connecting substrates. The field-induced height variation of the floating object was significantly influenced by the thicknesses of the dielectric and hydrophobic materials. A small mass was also placed on the top floating object and its effect on the spreading of the droplet was observed. In this system, the height of the top floating object is precisely controllable under the application of an electric voltage. The proposed system is expected to be highly useful in the design of nano- and micro-oscillatory systems for microengineering.

  17. New techniques for optical absorption measurement of implanted nanoparticles in float glass

    International Nuclear Information System (INIS)

    New techniques are reported for optical absorption and waveguide loss measurement of copper, gold and silver implanted float glass. Implantations were carried out on the tin face of the float glass since this face is an optical waveguide. Specially made triangle shape masks were used during implantation to study the optical loss-implant length relation. Absorption coefficients were extracted as 2.4 and 1 cm-1 for the gold and silver implants at 633 nm, respectively. These values were found to be implant condition dependent. To analyse the shape of nanoparticles a sandwiched structure was used in an optical absorption measurement set-up in which two guiding faces were put in contact. The sandwiched structure places the colloids at the centre of the optical field distribution rather than on the boundary zone. These experiments have revealed that the copper and the gold particles may have non-spherical shapes, whereas for silver, the formation of spherical nanoparticles is more likely

  18. Damping Wind and Wave Loads on a Floating Wind Turbine

    Directory of Open Access Journals (Sweden)

    Torben Knudsen

    2013-08-01

    Full Text Available Offshore wind energy capitalizes on the higher and less turbulent wind speeds at sea. To enable deployment of wind turbines in deep-water locations, structures are being explored, where wind turbines are placed on a floating platform. This combined structure presents a new control problem, due to the partly unconstrained movement of the platform and ocean wave excitation. If this additional complexity is not dealt with properly, this may lead to a significant increase in the structural loads and, potentially, instability of the controlled system. In this paper, the wave excitation is investigated, and we show the influence that both wind speed, wave frequencies and misalignment between wind and waves have on the system dynamics. A new control model is derived that extends standard turbine models to include the hydrodynamics, additional platform degrees of freedom, the platform mooring system and tower side-side motion, including gyroscopic effects. The models support a model-based design that includes estimators for wind speed and wave frequency. The design is applied to a number of examples representing different wind and wave conditions and successfully demonstrates a reduction in the structural oscillations, while improving power performance.

  19. Exploring float glass powder as corrosion resistant glass coating applied to concrete by flame spraying

    OpenAIRE

    Zhang, Li

    2014-01-01

    Float glass was chosen as precursor material to generate protective coatings on concrete structures against chemical attack. The method of application was flame spraying. The feedstock for flame spraying was in form of powders. The preparation methods (dry ball milling and spray drying) affected the morphology, the particle size distribution and the spray ability of the coating powders. Compared to as-sprayed coatings from dry ball milled powders, coatings from the spray dried powders had a m...

  20. Semiactive control for floating offshore wind turbines subject to aero-hydro dynamic loads

    OpenAIRE

    Luo, Ningsu; Bottasso, Carlo; Karimi, Hamid Reza; Zapateiro, Mauricio

    2011-01-01

    Wind and wave dynamic loads might cause undesirable vibrations that affect the structure integrity and system performance of floating offshore wind turbines. This paper addresses the problem of dynamic load mitigation by using semiactive control techniques with the tuned liquid column dampers placed on the turbine’s tower. The control law is formulated based on the mixed H2/H∞ methods for ensuring the system stability and reliability. Furthermore, the proposed controller only uses ou...

  1. Methodology to study the life cycle cost of floating offshore wind farms

    OpenAIRE

    Castro-Santos, Laura; Garcia, Geuffer; Diaz-Casas, Vicente

    2013-01-01

    The main objective of this paper is to determine a theoretical methodology process to study the life cycle cost of floating offshore wind farms. The principal purpose is adapting the LCC (Life-Cycle Cost Calculation) from several authors to the offshore wind energy world, providing a new method which will be called LCSFOWF. In this sense, several general steps will be defined: life cycle definition, process breakdown structure, viability study and sensitivity study. Moreover, technical and ...

  2. A Floating Ocean Energy Conversion Device and Numerical Study on Buoy Shape and Performance

    OpenAIRE

    Ruiyin Song; Meiqin Zhang; Xiaohua Qian; Xiancheng Wang; Yong Ming Dai; Junhua Chen

    2016-01-01

    Wave and current energy can be harnessed in the East China Sea and South China Sea; however, both areas are subject to high frequencies of typhoon events. To improve the safety of the ocean energy conversion device, a Floating Ocean Energy Conversion Device (FOECD) with a single mooring system is proposed, which can be towed to avoid severe ocean conditions or for regular maintenance. In this paper, the structure of the FOECD is introduced, and it includes a catamaran platform, an oscillating...

  3. Modelling and dynamic analysis of a semi-submersible floating vertical axis wind turbine

    OpenAIRE

    Wang, Kai

    2015-01-01

    Wind turbines are mainly classified into horizontal axis wind turbines (HAWTs) and vertical axis wind turbines (VAWTs) based on different orientation of their axis of rotation. Ever-increasing demand for energy boosts the application of the wind turbines in the deep water. The applications of HAWTs in deep water using different floating support structures have led to an increasing and versatile research due to their commercial success. However, the application of the VAWTs in t...

  4. Damage identification of a TLP floating wind turbine by meta-heuristic algorithms

    Science.gov (United States)

    Ettefagh, M. M.

    2015-12-01

    Damage identification of the offshore floating wind turbine by vibration/dynamic signals is one of the important and new research fields in the Structural Health Monitoring (SHM). In this paper a new damage identification method is proposed based on meta-heuristic algorithms using the dynamic response of the TLP (Tension-Leg Platform) floating wind turbine structure. The Genetic Algorithms (GA), Artificial Immune System (AIS), Particle Swarm Optimization (PSO), and Artificial Bee Colony (ABC) are chosen for minimizing the object function, defined properly for damage identification purpose. In addition to studying the capability of mentioned algorithms in correctly identifying the damage, the effect of the response type on the results of identification is studied. Also, the results of proposed damage identification are investigated with considering possible uncertainties of the structure. Finally, for evaluating the proposed method in real condition, a 1/100 scaled experimental setup of TLP Floating Wind Turbine (TLPFWT) is provided in a laboratory scale and the proposed damage identification method is applied to the scaled turbine.

  5. Nuclear Security for Floating Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Skiba, James M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Scherer, Carolynn P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-10-13

    Recently there has been a lot of interest in small modular reactors. A specific type of these small modular reactors (SMR,) are marine based power plants called floating nuclear power plants (FNPP). These FNPPs are typically built by countries with extensive knowledge of nuclear energy, such as Russia, France, China and the US. These FNPPs are built in one country and then sent to countries in need of power and/or seawater desalination. Fifteen countries have expressed interest in acquiring such power stations. Some designs for such power stations are briefly summarized. Several different avenues for cooperation in FNPP technology are proposed, including IAEA nuclear security (i.e. safeguards), multilateral or bilateral agreements, and working with Russian design that incorporates nuclear safeguards for IAEA inspections in non-nuclear weapons states

  6. Nuclear Security for Floating Nuclear Power Plants

    International Nuclear Information System (INIS)

    Recently there has been a lot of interest in small modular reactors. A specific type of these small modular reactors (SMR,) are marine based power plants called floating nuclear power plants (FNPP). These FNPPs are typically built by countries with extensive knowledge of nuclear energy, such as Russia, France, China and the US. These FNPPs are built in one country and then sent to countries in need of power and/or seawater desalination. Fifteen countries have expressed interest in acquiring such power stations. Some designs for such power stations are briefly summarized. Several different avenues for cooperation in FNPP technology are proposed, including IAEA nuclear security (i.e. safeguards), multilateral or bilateral agreements, and working with Russian design that incorporates nuclear safeguards for IAEA inspections in non-nuclear weapons states

  7. STM imaging of electrically floating islands

    Science.gov (United States)

    Realpe, H.; Shamir, N.; Mintz, M. H.; Manassen, Y.

    2006-07-01

    Appearances and disappearances of Gd islands grown on top of a W(1 1 0) substrate were observed in time scales of hours after exposing the surface to a few Langmuirs of hydrogen. The phenomenon is presented and explained in terms of (temporary) creation of electrically floating islands, due to electrical decoupling of the island and substrate by the hydrogen that diffuses into the island/substrate interface. The disappearance of such an island is explained by forming a double barrier junction consisting of two tunneling barriers in series, causing, by charging, the potential of the island to become equal to that of the tip. The island then becomes "invisible" and the tip follows the corrugation of the surface under the substrate. The reappearance follows hydrogen mobility that retains the electrical conductivity of the island-substrate interface.

  8. UFO: "Unidentified" Floating Object Driven by Thermocapillarity

    CERN Document Server

    Zhao, Yuejun

    2010-01-01

    In this fluid dynamics video, we show thermocapillary actuation of a binary drop of water and heptanol where the binary drop in motion takes on a UFO-like shape. On a parylene-coated silicon surface subjected to a linear temperature gradient, a pure heptanol droplet quickly moves to the cold side by the Marangoni stress, while a pure water droplet remains stuck due to a large contact angle hysteresis. When the water droplet was encapsulated by a thin layer of heptanol and thermally actuated, the binary droplet takes on a peculiar shape resembling an UFO, i.e. an "unidentified" floating object as the mechanism is not yet completely understood. Our finding suggests that pure liquid droplets (e.g. aqueous solutions) that are not conducive to thermocapillary actuation can be made so by encapsulating them with another judiciously chosen liquid (e.g. heptanol).

  9. Electron inertia effect on floating plasma potential

    International Nuclear Information System (INIS)

    The steady one-dimensional planar plasma sheath problem, originally considered by Tonks and Langmuir, is revisited. Two-fluid equations for cold ions and isothermal electrons, including terms for particle generation and electron inertia, have been numerically integrated together with Poisson equation. The inclusion of electron inertia in the model allows us to obtain the value of the plasma floating potential as resulting from an electron density discontinuity at the walls, where the electrons attain sound velocity and the electric potential is continuous. Results from numerical computation are presented in terms of plots for densities, electric potential and particles velocities. Comparison with results from literature, corresponding to electron Maxwell-Boltzmann distribution (neglecting electron inertia), are also shown.

  10. Analysis of Switched-Rigid Floating Oscillator

    Directory of Open Access Journals (Sweden)

    Prabhakar R. Marur

    2009-01-01

    Full Text Available In explicit finite element simulations, a technique called deformable-to-rigid (D2R switching is used routinely to reduce the computation time. Using the D2R option, the deformable parts in the model can be switched to rigid and reverted back to deformable when needed during the analysis. The time of activation of D2R however influences the overall dynamics of the system being analyzed. In this paper, a theoretical basis for the selection of time of rigid switching based on system energy is established. A floating oscillator problem is investigated for this purpose and closed-form analytical expressions are derived for different phases in rigid switching. The analytical expressions are validated by comparing the theoretical results with numerical computations.

  11. Hydroelastic response of a floating runway to cnoidal waves

    Energy Technology Data Exchange (ETDEWEB)

    Ertekin, R. C., E-mail: ertekin@hawaii.edu [Department of Ocean and Resources Engineering, University of Hawaii at Manoa, Honolulu, Hawaii 96822 (United States); Xia, Dingwu [Engineering Services, British Petroleum GoM, Houston, Texas 77079 (United States)

    2014-02-15

    The hydroelastic response of mat-type Very Large Floating Structures (VLFSs) to severe sea conditions, such as tsunamis and hurricanes, must be assessed for safety and survivability. An efficient and robust nonlinear hydroelastic model is required to predict accurately the motion of and the dynamic loads on a VLFS due to such large waves. We develop a nonlinear theory to predict the hydroelastic response of a VLFS in the presence of cnoidal waves and compare the predictions with the linear theory that is also developed here. This hydroelastic problem is formulated by directly coupling the structure with the fluid, by use of the Level I Green-Naghdi theory for the fluid motion and the Kirchhoff thin plate theory for the runway. The coupled fluid structure system, together with the appropriate jump conditions are solved in two-dimensions by the finite-difference method. The numerical model is used to study the nonlinear response of a VLFS to storm waves which are modeled by use of the cnoidal-wave theory. Parametric studies show that the nonlinearity of the waves is very important in accurately predicting the dynamic bending moment and wave run-up on a VLFS in high seas.

  12. 119Sn Moessbauer spectroscopy of tin containing float glass

    International Nuclear Information System (INIS)

    According to the production process of float glasses tin is used as a common refining agent. Since the surface quality of the glass strongly depends on the local distribution of Sn-redox states, the influence of process parameters on Sn2+/Sn4+ ratios and the assignment to their structural role in the glass network is extremely helpful. Therefore, glass compositions based on SiO2-Al2O3-B2O3-CaO-SnO2 were molten with additions of 0,1, 0,3 and 0,5 wt% SnO2. All samples were tempered for 7 days at 1400 C in N2 and N2-air mixtures with controlled pO2-values of 10-2 and 10-5 bar, respectively. Hyperfine parameters for the tin nucleus in different structural units and their oxidation states were calculated from 119Sn Moessbauer spectra, using theoretical simulations of electron densities and electric field gradients with the Wien2k software. Finally, the thermochemical impact of oxygen on the structure of Sn-bearing glasses is discussed

  13. Present situation of floating nuclear power plants

    International Nuclear Information System (INIS)

    The present situation of investigation and the future problems of floating nuclear power plants in Japan are examined, referring to those in USA. The committee report on a new power generation system in 1970 is quoted. In this report, the site conditions are supposed to be 5 km offshore, 100m water depth, 60 m/sec wind velocity, 10 m wave height, 200 m wave length, 12 seconds wave period 0.2 g earthquake acceleration, and 2.5 knots tide current. The semisubmersible hull of double construction 15 m under water is employed. A pair of 1,000,000 kW BWR reactors are utilized. A sea water desalting unit using bleed steam from turbines is installed. The solid radioactive wastes packed in drums are disposed in sea. The design and cost estimation were made. The names of the organizations who have made investigation in this field, namely the Civil Engineering Society, the Sience and Technology Agency and other several centers, are reported. The Chubu Electric Power Company is forwarding its project. Referring to the investigations in USA, the project of Atlantic nuclear power station unit is described. A report of plant design has been submitted by O.P.S. to United States Atomic Energy Commission in 1973. The Coastal Area Facilities Act was instituted in New Jersey in 1973. Although the Atlantic nuclear power station has been postponed, it is the most feasible project. For the realization of a floating nuclear power plant in Japan, investigation must be started on the ground construction that can endure the construction of breakwater in water depth of 14 to 30 meter. (Iwakiri, K.)

  14. Porous carrier based floating granular delivery system of repaglinide.

    Science.gov (United States)

    Jain, Sunil K; Agrawal, Govind P; Jain, Narendra K

    2007-04-01

    A floating granular delivery system consisting of calcium silicate (CS) as porous carrier; repaglinide (Rg), an oral hypoglycemic agent; and hydroxypropyl methylcellulose K4M (HPMC K4M), ethyl cellulose (EC) and carbopol 940 (CP940) as matrix forming polymers was prepared and evaluated for its gastro-retentive and controlled release properties. The effect of various formulation and process variables on the particle morphology, micromeritic properties, in vitro floating behavior, drug content (%) and in vitro drug release was studied. The transit of floating granules of optimized formulation in the gastrointestinal (GI) tract was monitored by gamma scintigraphy in albino rabbits. The optimized formulation was compared in vivo with lactose granules (RgSCLG) prepared from identical polymers with their optimized composition ratio. Repaglinide-loaded optimized formulation was orally administered to albino rabbits and blood samples collected were used to determine pharmacokinetic parameters of Rg from floating granular formulation. Results were compared with pharmacokinetic parameters of marketed tablet formulation of Rg. The optimized formulation (RgSCG4) demonstrated favorable in vitro floating and release characteristics. Prolonged gastric residence time (GRT) of over 6 hr was achieved in all subjects for calcium silicate based floating granules of Rg. The relative bioavailability of Rg-loaded floating granules increased 3.8-fold in comparison to that of its marketed capsule. The designed system, combining excellent buoyant ability and suitable drug release pattern, offered clear advantages in terms of increased bioavailability of repaglinide. PMID:17523003

  15. PERANCANGAN FLOATING DOCK UNTUK DAERAH PERAIRAN PELABUHAN KOTA TEGAL

    Directory of Open Access Journals (Sweden)

    Kiryanto Kiryanto

    2013-06-01

    Full Text Available Floating dock merupakan bangunan air sebagai tempat reparasi kapal yang dinilai cukup efisien dalam pembangunannya karena tidak membutuhkan dana yang terlalu mahal. Di sektor indusrti perkapalan kota tegal sudah memiliki galangan dan dock reparasi kapal yang cukup berkembang.  Ide perancangan floating dock ini dirancang sebagai alternatif baru pelayanan reparasi kapal. Perancangan floating dock ini juga memperhatikan dengan detail kapasitas kapal – kapal yang pernah melakukan repararasi di sekitar galangan di Kota Tegal agar ditemukan ukuran utama floating dock yang tepat. Dari Kapasitas kapal yang ada dan berdasarkan metode perbandingan ukuran beberapa floating dock, maka ditemukan ukuran utama yang tepat untuk menampung kebutuhan pelayanan reparasi kapal yaitu LOA = 136,37 m, Lpt = 114.80 m, Bmax = 36,40 m, Bmd: 30,80 m, Tmin = 0,86 m, Tmax = 1,58 m, Hpt = 2,10 m, HOA = 9,60 m. Berdasarkan perhitungan ditemukan juga Ton Lifting Capacity (TLC sebesar 3000 ton. Perancangan menggunakan software perkapalan yaitu dengan menggunakan AutoCad, Delftship, Maxsurf dan Hidromax. Dengan analisa stabilitas menggunakan software Hidromax diketahui bahwa floating dock ini mampu memiliki stabilitas yang baik dengan 4 kondisi yang semua memenuhi criteria  International Maritime Organisation (IMO. Perancangan floating dock ini juga menghitung analisa ekonomis dan investasi. Dari rekapitulasi dana investasi pembangunan floating dock yaitu sebesar Rp.136.622.888.000,00 dengan nilai kembali atau break even point selama 10 tahun dengan modal sendiri, 14 tahun dengan 50% modal sendiri dan 50 % pinjaman bank, dan break event point 18 tahun untuk dana pembangunan floating dock yang berasal dari 100 % pinjaman bank

  16. Recent advances in gastric floating drug delivery technology: a review.

    Science.gov (United States)

    Pahwa, Rakesh; Bisht, Seema; Kumar, Vipin; Kohli, Kanchan

    2013-06-01

    Gastric floating drug delivery systems have been an avenue of considerable interest in terms of their immense potential for better pharmacotherapeutic interventions along with site-specific absorption. These buoyant systems significantly enhance the bioavailability and controlled delivery of several drug molecules. Scientific investigators have also carried out substantial research endeavours worldwide in order to design a more systematic and intellectual floating systems. The present manuscript is an attempt to highlight numerous recent advancements in the design of gastric floating drug delivery systems along with various available commercial preparations. Salient applications, characterization aspects and future perspectives of these multifarious systems have also been addressed. PMID:23808593

  17. Radiation response of floating gate EEPROM memory cells

    International Nuclear Information System (INIS)

    The effect of radiation on a floating gate EEPROM nonvolatile memory cell is determined experimentally and modeled analytically. The new model predicts the threshold voltage change resulting from radiation. A screen based on the initial 1 state (excess electron) threshold voltage is shown to be necessary to assure data retention during irradiation. Techniques to increase radiation hardness are also described. The hardness of floating gate cells is shown to be limited to less than 100 krad(Si) for a fixed reference sense amplifier. The use of a differential sense amplifier may increase this limit. Therefore, floating gate memories should be useful for those applications requiring low total-doses

  18. THE FLOATING ISLAND OF POSTA FIBRENO: AN EXAMPLE OF A RELIC MIRE IN CENTRAL ITALY

    Directory of Open Access Journals (Sweden)

    E. AGRILLO

    2010-01-01

    Full Text Available The lake of Posta Fibreno (S Latium, C. Italy, is a biotope where some outstanding anomalies in the flora and vegetation of the wetlands of peninsular Italy are concentrated. Here the southernmost Italian populations of Sphagnum palustre occur on the small surface of a floating island, a cup-formed core of Sphagnum peat and rhizomes of Helophytes, erratically floating on the water-body of a submerged doline, annexed to the easternmost edge of the lake, characterised by the extension of a large reed bed. A strong correlation between characteristics of the physical environment and the structure of the vegetation on the island, points out the descriptive ability of the communities recorded in the site to reconstruc the genesis of the biotope.

  19. Floating Offshore Wind in Hawaii: Potential for Jobs and Economic Impacts from Three Future Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, Tony; Keyser, David; Tegen, Suzanne

    2016-04-18

    Construction of the first offshore wind power plant in the United States began in 2015, off the coast of Rhode Island, using fixed platform structures that are appropriate for shallow seafloors, like those located off the East Coast and mid-Atlantic. However, floating platforms, which have yet to be deployed commercially, will likely need to be anchored to the deeper seafloor if deployed in Hawaiian waters. To analyze the employment and economic potential for floating offshore wind off Hawaii's coasts, the Bureau of Ocean Energy Management commissioned the National Renewable Energy Laboratory (NREL) to analyze two hypothetical deployment scenarios for Hawaii: 400 MW of offshore wind by 2050 and 800 MW of offshore wind by 2050. The results of this analysis can be used to better understand the general scale of economic opportunities that could result from offshore wind development.

  20. 1T Pixel Using Floating-Body MOSFET for CMOS Image Sensors.

    Science.gov (United States)

    Lu, Guo-Neng; Tournier, Arnaud; Roy, François; Deschamps, Benoît

    2009-01-01

    We present a single-transistor pixel for CMOS image sensors (CIS). It is a floating-body MOSFET structure, which is used as photo-sensing device and source-follower transistor, and can be controlled to store and evacuate charges. Our investigation into this 1T pixel structure includes modeling to obtain analytical description of conversion gain. Model validation has been done by comparing theoretical predictions and experimental results. On the other hand, the 1T pixel structure has been implemented in different configurations, including rectangular-gate and ring-gate designs, and variations of oxidation parameters for the fabrication process. The pixel characteristics are presented and discussed. PMID:22389592

  1. Generation of three-dimensional multiple spheroid model of olfactory ensheathing cells using floating liquid marbles

    Science.gov (United States)

    Vadivelu, Raja K.; Ooi, Chin H.; Yao, Rebecca-Qing; Tello Velasquez, Johana; Pastrana, Erika; Diaz-Nido, Javier; Lim, Filip; Ekberg, Jenny A. K.; Nguyen, Nam-Trung; St John, James A.

    2015-10-01

    We describe a novel protocol for three-dimensional culturing of olfactory ensheathing cells (OECs), which can be used to understand how OECs interact with other cells in three dimensions. Transplantation of OECs is being trialled for repair of the paralysed spinal cord, with promising but variable results and thus the therapy needs improving. To date, studies of OEC behaviour in a multicellular environment have been hampered by the lack of suitable three-dimensional cell culture models. Here, we exploit the floating liquid marble, a liquid droplet coated with hydrophobic powder and placed on a liquid bath. The presence of the liquid bath increases the humidity and minimises the effect of evaporation. Floating liquid marbles allow the OECs to freely associate and interact to produce OEC spheroids with uniform shapes and sizes. In contrast, a sessile liquid marble on a solid surface suffers from evaporation and the cells aggregate with irregular shapes. We used floating liquid marbles to co-culture OECs with Schwann cells and astrocytes which formed natural structures without the confines of gels or bounding layers. This protocol can be used to determine how OECs and other cell types associate and interact while forming complex cell structures.

  2. Influence of Model Simplifications Excitation Force in Surge for a Floating Foundation for Offshore Wind Turbines

    Directory of Open Access Journals (Sweden)

    Morten Thøtt Andersen

    2015-04-01

    Full Text Available As offshore wind turbines move towards deeper and more distant sites, the concept of floating foundations is a potential technically and economically attractive alternative to the traditional fixed foundations. Unlike the well-studied monopile, the geometry of a floating foundation is complex and, thereby, increases the difficulty in wave force determination due to limitations of the commonly used simplified methods. This paper deals with a physical model test of the hydrodynamic excitation force in surge on a fixed three-columned structure intended as a floating foundation for offshore wind turbines. The experiments were conducted in a wave basin at Aalborg University. The test results are compared with a Boundary Element Method code based on linear diffraction theory for different wave force regimes defined by the column diameter, wave heights and lengths. Furthermore, the study investigates the influence of incident wave direction and stabilizing heave-plates. The structure can be divided into primary, secondary and tertiary parts, defined by the columns, heave-plates and braces to determine the excitation force in surge. The test results are in good agreement with the numerical computation for the primary parts only, which leads to simplified determination of peak frequencies and corresponding dominant force regime.

  3. A comparison between the dynamics of horizontal and vertical axis offshore floating wind turbines.

    Science.gov (United States)

    Borg, M; Collu, M

    2015-02-28

    The need to further exploit offshore wind resources in deeper waters has led to a re-emerging interest in vertical axis wind turbines (VAWTs) for floating foundation applications. However, there has been little effort to systematically compare VAWTs to the more conventional horizontal axis wind turbine (HAWT). This article initiates this comparison based on prime principles, focusing on the turbine aerodynamic forces and their impact on the floating wind turbine static and dynamic responses. VAWTs generate substantially different aerodynamic forces on the support structure, in particular, a potentially lower inclining moment and a substantially higher torque than HAWTs. Considering the static stability requirements, the advantages of a lower inclining moment, a lower wind turbine mass and a lower centre of gravity are illustrated, all of which are exploitable to have a less costly support structure. Floating VAWTs experience increased motion in the frequency range surrounding the turbine [number of blades]×[rotational speed] frequency. For very large VAWTs with slower rotational speeds, this frequency range may significantly overlap with the range of wave excitation forces. Quantitative considerations are undertaken comparing the reference NREL 5 MW HAWT with the NOVA 5 MW VAWT. PMID:25583856

  4. Dynamics modeling and loads analysis of an offshore floating wind turbine

    Science.gov (United States)

    Jonkman, Jason Mark

    -based turbine. Instabilities were also found in the system. The influence of conventional wind turbine blade-pitch control actions on the pitch damping of the floating turbine was also assessed. Design modifications for reducing the platform motions, improving the turbine response, and eliminating the instabilities are suggested. These suggestions are aimed at obtaining cost-effective designs that achieve favorable performance while maintaining structural integrity.

  5. High voltage switches having one or more floating conductor layers

    Science.gov (United States)

    Werne, Roger W.; Sampayan, Stephen; Harris, John Richardson

    2015-11-24

    This patent document discloses high voltage switches that include one or more electrically floating conductor layers that are isolated from one another in the dielectric medium between the top and bottom switch electrodes. The presence of the one or more electrically floating conductor layers between the top and bottom switch electrodes allow the dielectric medium between the top and bottom switch electrodes to exhibit a higher breakdown voltage than the breakdown voltage when the one or more electrically floating conductor layers are not present between the top and bottom switch electrodes. This increased breakdown voltage in the presence of one or more electrically floating conductor layers in a dielectric medium enables the switch to supply a higher voltage for various high voltage circuits and electric systems.

  6. Can Heavier Liquid Float on Top of a Lighter One?

    Institute of Scientific and Technical Information of China (English)

    A. H. Ayyad; F. Takrori

    2011-01-01

    We report on a first observation of a floating spherical Hg (density 13g/cm3) drop on top of a glycerin (density 1.26g/cm3) drop, the latter is hemispherical and about four times larger in volume. This observation is clearly against nature's gravity law and has never been reported before. Here we present spectacular high resolution photos that clearly demonstrate this remarkable floating phenomenon. Using milli-Q water, the Hg drop would stay down adhered at the triple line. Instead, the coincidental use of tap water displays the same phenomenon. Increasing the volume of the supporting liquid to a certain value causes the Hg drop to sink. A 5-M NaCl aqueous solution is found enough to show the same floating phenomenon. This floating mercury as a phenomenon is puzzling. On this length scale it seems that surface tension and curvature dominate over gravity.

  7. Multifractal analysis of managed and independent float exchange rates

    Science.gov (United States)

    Stošić, Darko; Stošić, Dusan; Stošić, Tatijana; Stanley, H. Eugene

    2015-06-01

    We investigate multifractal properties of daily price changes in currency rates using the multifractal detrended fluctuation analysis (MF-DFA). We analyze managed and independent floating currency rates in eight countries, and determine the changes in multifractal spectrum when transitioning between the two regimes. We find that after the transition from managed to independent float regime the changes in multifractal spectrum (position of maximum and width) indicate an increase in market efficiency. The observed changes are more pronounced for developed countries that have a well established trading market. After shuffling the series, we find that the multifractality is due to both probability density function and long term correlations for managed float regime, while for independent float regime multifractality is in most cases caused by broad probability density function.

  8. Preparation and evaluation of gastroretentive floating tablets of acyclovir.

    Science.gov (United States)

    Garg, Rajeev; Gupta, G D

    2009-10-01

    The present study performed by preparation and evaluation of floating tablets of Acyclovir as model drug for prolongation of gastric residence time. Floating effervescent tablets were formulated by various materials like hydroxypropyl methylcellulose K 4M, K 15M, psyllium husk, swelling agent as crospovidone and microcrystalline cellulose and gas generating agent like sodium bicarbonate and citric acid and evaluated for floating properties, swelling characteristics and in vitro drug release studies. Floating noneffervescent tablets were prepared by polypropylene foam powder and different matrix forming polymers like HPMC K 4M, Carbopol 934P, xanthan gum and sodium alginate. In vitro drug release studies were performed and drug release kinetics evaluated using the linear regression method was found to follow both the Higuchi and the Korsmeyer and Peppas equation. The drug release mechanism was found fickian type in most of the formulations. PMID:19751200

  9. Geologic Observations-Oregon OCS Floating Wind Farm Site

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of the Oregon Outer Continental Shelf (OCS) Floating Windfarm Suite Data Release presents geological observations from video collected on U.S. Geological...

  10. Bathymetry Hillshade-Oregon OCS Floating Wind Farm Site

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This Data Release contains data from the USGS survey of the Oregon OCS Floating Wind Farm Site in 2014. The shaded-relief raster was generated from bathymetry data...

  11. Contours-Oregon OCS Floating Wind Farm Site

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This Data Release contains data from the USGS field activity 2014-607-FA, a survey of the Oregon Outer Continental Shelf (OCS) Floating Wind Farm Site in 2014. The...

  12. Can Heavier Liquid Float on Top of a Lighter One?

    International Nuclear Information System (INIS)

    We report on a first observation of a floating spherical Hg (density 13 g/cm3) drop on top of a glycerin (density 1.26 g/cm3) drop, the latter is hemispherical and about four times larger in volume. This observation is clearly against nature's gravity law and has never been reported before. Here we present spectacular high resolution photos that clearly demonstrate this remarkable floating phenomenon. Using milli-Q water, the Hg drop would stay down adhered at the triple line. Instead, the coincidental use of tap water displays the same phenomenon. Increasing the volume of the supporting liquid to a certain value causes the Hg drop to sink. A 5-M NaCl aqueous solution is found enough to show the same floating phenomenon. This floating mercury as a phenomenon is puzzling. On this length scale it seems that surface tension and curvature dominate over gravity. (fundamental areas of phenomenology (including applications))

  13. 14 CFR 27.521 - Float landing conditions.

    Science.gov (United States)

    2010-01-01

    ... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Water Loads § 27.521 Float landing..., the load share determined under paragraph (b)(1) of this section, combined with a total side load of...

  14. Bathymetry-Oregon OCS Floating Wind Farm Site

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This Data Release contains data from the U.S. Geological Survey (USGS) survey of the Oregon outer continental shelf (OCS) Floating Wind Farm Site in 2014. The...

  15. Backscatter-Oregon OCS Floating Wind Farm Site

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This Data Release contains data from the U.S. Geological Survey (USGS) survey of the Oregon outer Continental shelf (OCS) Floating Wind Farm Site in 2014. The...

  16. DEVELOPMENT AND EVALUATION OF FLOATING-MUCOADHESIVE DIPYRIDAMOLE TABLET

    OpenAIRE

    BIRAJDAR SHIVPRASAD M. DARVESHWAR JAGDEEP D

    2013-01-01

    The present study was aimed towards development and evaluation of tablet as a floating-Mucoadhesive drug delivery system, which can provide sustained release of the model drug. The work also was aimed to study various parameters affecting the behavior of floating-mucoadhesive tablet in oral dosage form. Formulation of Gastro-Retentive Dosage Forms (GRDFs) containing suitable drug candidate which would remain in stomach and/or upper part of GIT for prolonged period of time thereby is maximizin...

  17. Formulation and Evaluation of Floating Drug Delivery System of Famotidine

    OpenAIRE

    Satishbabu, B. K.; Sandeep, V. R.; Ravi, R. B.; Shrutinag, R.

    2010-01-01

    A multiple unit oral floating drug delivery system of famotidine was developed to prolong gastric residence time, target stomach mucosa and increase drug bioavailability. Drug and polymer compatibility was studied by subjecting physical mixtures of drug and polymers to differential scanning calorimetry. Cod liver oil entrapped calcium alginate beads containing famotidine, capable of floating in the gastric condition were formulated and evaluated. The gel beads were prepared by emulsion gelati...

  18. Development, evaluation and optimization of baclofen oral floating tablet

    OpenAIRE

    Singh, Akhilesh V.; Pandey, Rishabh D.; Nath, Lila K.; Das, Anudwipa

    2010-01-01

    The present investigation concerns the development of a floating matrix tablet, which after oral administration prolong the gastric residence time and increases bioavailability of drugs, which are predominantly absorbed from gastric region .With this aim, floating dosage form containing baclofen as drug, and different grades of HPMC as release retarding polymer was prepared. Sodium bicarbonate and citric acid were used as gas generating agents. Some factors were investigated concerning the ef...

  19. Seismic monitoring in the oceans by autonomous floats

    OpenAIRE

    Sukhovich, Alexey; Bonnieux, Sébastien; Hello, Yann; Irisson, Jean-Olivier; Simons, Frederik J.; Nolet, Guust

    2015-01-01

    Our understanding of the internal dynamics of the Earth is largely based on images of seismic velocity variations in the mantle obtained with global tomography. However, our ability to image the mantle is severely hampered by a lack of seismic data collected in marine areas. Here we report observations made under different noise conditions (in the Mediterranean Sea, the Indian and Pacific Oceans) by a submarine floating seismograph, and show that such floats are able to fill the oceanic data ...

  20. NUMERICAL ANALYSIS OF IRREGULAR-SHAPED FLOATING BREAKWATER

    OpenAIRE

    Mahmuddin, Faisal

    2008-01-01

    It is known that the floating type of breakwater is more preferable than conventional or fixed-type one especially by considering its economical and technical benefits. However, the common shape of a floating breakwater, which is usually simply a rectangular shape, could only attenuate waves in a limited range of frequency especially in short wavelength region. In longer wavelength region, it will just move following the seawater motions as a small object. In order to address this problem, an...

  1. Precision Arithmetic: A New Floating-Point Arithmetic

    OpenAIRE

    Wang, Chengpu

    2006-01-01

    A new deterministic floating-point arithmetic called precision arithmetic is developed to track precision for arithmetic calculations. It uses a novel rounding scheme to avoid excessive rounding error propagation of conventional floating-point arithmetic. Unlike interval arithmetic, its uncertainty tracking is based on statistics and the central limit theorem, with a much tighter bounding range. Its stable rounding error distribution is approximated by a truncated normal distribution. Generic...

  2. Dynamic response of a floating offshore wind turbine

    OpenAIRE

    Stølsmark, Rasmus

    2010-01-01

    The ever increasing demand for renewable energy, combined with limited areas suitable for large wind farms, has put focus on the development of floating wind turbines. In this thesis the dynamic response of a floating wind turbine, subjected to forces from wind and waves, is analyzed. The wind turbine is of a spar buoy design, similar to Statoil's Hywind project. Simulations with two main type of load cases were run, based on the international offshore wind turbine standard IEC...

  3. Concomitant ligamentous and meniscal injuries in floating knee

    OpenAIRE

    Liu, Ya; Jun ZHANG; Zhang, Shu; Li, Rui; Yue, Xianhu

    2015-01-01

    Background: To identify and characterize the concomitant ligamentous and meniscal injuries in floating knee. Methods: A total of 37 cases of floating knee were enrolled. Arthroscopic or open surgical examination of the knee, Lachman test, posterior drawer’s test, and varus and valgus stress tests under anesthesia were carried out to determine the incidence of knee injury. Results: Through arthroscopic and open surgical examinations, a medial meniscal tear was detected in 14 (37.8%) cases and ...

  4. Design of Floating Point Arithmetic Logic Unit with Universal Gate

    OpenAIRE

    Shraddha N. Zanjat; Dr.S.D.Chede; Prof.B.J.Chilke

    2014-01-01

    A floating point arithmetic and logic unit design using pipelining is proposed. By using pipeline with ALU design, ALU provides a high performance. With pipelining plus parallel processing concept ALU execute multiple instructions simultaneously. Floating point ALU unit is formed by combination of arithmetic modules (addition, subtraction, multiplication, division), Universal gate module. Each module is divided into sub-module. Bits selection determines which operation takes place at a partic...

  5. Formulation and evaluation of floating tablets of liquorice extract

    OpenAIRE

    H N Aswatha Ram; Prachiti Lachake; Ujjwal Kaushik; C S Shreedhara

    2010-01-01

    Background: Floating tablets prolong the gastric residence time of drugs, improve bioavailability, and facilitate local drug delivery to the stomach. With this objective, floating tablets containing aqueous extract of liquorice as drug was prepared for the treatment of Helicobacter pylori and gastric ulcers. Methods: The aqueous extract of liquorice was standardized by HPTLC. Tablets containing HPMC K100M (hydrophilic polymer), liquorice extract, sodium bicarbonate (gas generating agent), tal...

  6. Towards a Completion of Archimedes' Treatise on Floating Bodies

    OpenAIRE

    Girstmair, Kurt; Kirchner, Gerhard

    2007-01-01

    In his treatise on floating bodies Archimedes determines the equilibrium positions of a floating paraboloid segment, but only in the case when the basis of the segment is either completely outside of the fluid or completely submerged. Here we give a mathematical model for the remaining case, i.e., two simple conditions which describe the equilibria in closed form. We provide tools for finding all equilibria in a reliable way and for the classification of these equilibria. This paper can be co...

  7. FORMULATION AND EVALUTION OF GASTRO RETENTIVE FLOATING TABLETS OF GLIPIZIDE

    Directory of Open Access Journals (Sweden)

    Raja Benhar Dickson

    2011-03-01

    Full Text Available A gastro retentive floating drug delivery system containing glipizide was prepared in the form of tablet and evaluated for its processing parameters and in vitro release behaviour. Glipizide is a selective second-generation sulphonyl urea used in treatment of hyperglycemia and it absorbs rapidly and completely. However its absorption is erratic in diabetic patient due to its impaired gastric motility or gastric emptying. To overcome these drawbacks, the present investigation was to develop a gastro retentive floating tablets of glipizide. Ten formulations containing retardant materials such as hydroxypropylmethylcellulose K4M and K15M, sodium bicarbonate was used as a gas generating agent to reduce floating lag time and other release promoters. Tablets remained buoyant over 12 hours in the release medium, and the amount of sodium bicarbonate found to be significant for not only to remaining buoyant without causing disintegration of the tablet, but also to release of the drug in the acidic medium. Final F6 optimized formulation released approximately 99% drug in 12 hours in vitro, while the floating lag time was 39 sec and tablet remained floatable throughout all studies. In vitro gastro retentive study of tablets gave successful results by floating in gastric content over a period of 24 hours. The results of the current study clearly indicate, a promising potential of the glipizide floating system as an alternative to the conventional dosage form.

  8. FORMULATION AND EVALUATION OF GASTRO RETENTIVE FLOATING TABLETS OF GLICLAZIDE

    Directory of Open Access Journals (Sweden)

    Thakkar Hardik Kumar Rajeshbhai

    2011-04-01

    Full Text Available A gastro retentive floating drug delivery system containing gliclazide was prepared in the form of tablet and evaluated for its processing parameters and in vitro release behaviour. Gliclazide is a selective second-generation sulphonyl urea used in treatment of hyperglycemia and it absorbs rapidly and completely. However its absorption is erratic in diabetic patient due to its impaired gastric motility or gastric emptying. To overcome these drawbacks, the present investigation was to develop a gastro retentive floating tablets of gliclazide. Ten formulations containing retardant materials such as hydroxypropylmethylcellulose K4M and K15M, sodium bicarbonate was used as a gas generating agent to reduce floating lag time and other release promoters. Tablets remained buoyant over 12 hours in the release medium, and the amount of sodium bicarbonate found to be significant for not only to remaining buoyant without causing disintegration of the tablet, but also to release of the drug in the acidic medium. Final F6 optimized formulation released approximately 99% drug in 12 hours in vitro, while the floating lag time was 39 sec and tablet remained floatable throughout all studies. In vitro gastro retentive study of tablets gave successful results by floating in gastric content over a period of 24 hours. The results of the current study clearly indicate, a promising potential of the gliclazide floating system as an alternative to the conventional dosage form.

  9. FORMULATION AND EVALUATION OF FLOATING TABLET OF AMOXICILLIN TRIHYDRATE

    Directory of Open Access Journals (Sweden)

    Yadav Varun T

    2012-05-01

    Full Text Available The present investigation concerns the design and evaluation of floating tablets of Amoxicillintrihydrate, which after oral administration, are designed to prolonged the gastric residence time and toobtain site-specific drug delivery for the stomach and increased drug bioavailability. Amoxicillin is aSemisynthetic antibiotic, belonging Beta-lactum family, which is effective for bacterial treatment,especially for helicobacter pylori infection. The dosage form was designed by using HPMC K100M,HPMC K15M and HPMC K4M polymers as gelling agents, sodium bicarbonate as gas-generating agentand other excipients. The interaction between drug and excipients in prepared floating tablets werestudied by differential scanning calorimetry (DSC and FT-IR. Floating tablets prepared by directcompression technique. The prepared floating tablets were evaluated in terms of their pre-compressionparameters, physical characteristics like hardness, friability, uniformity of weight, uniformity of drugcontent, swelling index, in-vitro floating studies, in-vitro drug release and short term stability studies..The floating properties and drug release characteristics were determined for the prepared tablets in 0.1 NHCl and water dissolution media. Dissolution Profile was compared with dissolution profile of marketedtablet. The data obtained from in-vitro dissolution studies were fitted in different models. Finaloptimized formulation batch F10 released 93.02% and 73.02% drug in 0.1N HCl and water respectively.

  10. 1-D DCT Using Latency Efficient Floating Point Algorithms

    Directory of Open Access Journals (Sweden)

    Viswanath Gowd A, Yedukondala Rao V, T. Shanmuganantham

    2013-04-01

    Full Text Available This paper presents the design of one-dimensional discrete cosine transform (DCT architecture for digital signal processing (DSP applications. DCT is a basic transformation for coding method which converts spatial domain to frequency domain of image. In 1-D DCT operation addition, subtraction, multiplication operations are required. These operations must be accurate, less latency. Floating point operations have dynamic range of representation, more accurate and perform millions of calculations per second. So the floating point operations are used for the above operations. In this floating point adder/subtractor is the most complex operation in a floating-point arithmetic and consists of many variable latency- and area dependent sub-operations. In floating-point addition implementations, latency is the primary performance bottleneck. So different types of floating point adder/subtractor algorithms such as LOD, LOP, Two-path are used to decrease the latency. The trade off is observed in 1-D DCT by changing different types of adders in place of summer. All architectures are designed and implemented using VHDL using Xillinx 13.1software.

  11. Spectral analysis of Floating Car Data

    Directory of Open Access Journals (Sweden)

    F. Gössel

    2003-01-01

    Full Text Available Floating Car Data (FCD are one important data source in traffic telematic systems. The original variable in these systems is the vehicle velocity. The paper analyses the measured value “vehicle velocity" by methods of information technology. Consequences for processing, transmission and storage of FCD under condition of limited resources are discussed. Starting point of the investigation is the analysis of spectral characteristics of velocity-time-profiles. The spectra are determined by the Discrete Fourier Transform (DFT from measurement data and simulation data of a microscopic traffic model. One essential property of velocity-time-profiles is their low-pass characteristic. The resulting cut-off-frequency is comparatively small and depends on the traffic scenario. Conclusions concerning the necessary sample rate in FCD systems and the processing of raw data are discussed. Finally the transinformation of velocity-time-profiles is analysed. This results in similar values for an optimal sample rate of FCD systems under condition of limited transmission capacity.

  12. RBI - Risk Based Inspection: new concept applied to management of FPSOs (Floating, Production and Storage Offshore) structural integrity; IBR-Inspecao baseada em risco: um novo conceito aplicado a gestao da integridade estrutural de FPSOs

    Energy Technology Data Exchange (ETDEWEB)

    Farias, Bruno de; Figueiredo, Eduardo; Luiz, Marcio [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Meurer, Gustavo; Duarte, Romulo; Belligotti, Rufo; Krzonkalla, Viviane [ABS Consulting, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    Due to the difficulties of adapting the plan of inspection, typical of oil tankers, the units of the FPSO, began to occur large periods of unavailability of the cargo tanks. Also, with the expansion of the fleet, began to notice a difficulty in meeting the plan of inspection of the FPSO's hull. To improve the management of structural integrity of its FPSO's, PETROBRAS aims to ABS Consulting with the development and implementation of Risk-Based Inspection, known as RBI. This concept is applicable to various branches of industry. The companies began their implementation of oil by refineries. The development application for a ship's hull is recent and PETROBRAS is one of the first companies to implement the IBR for monitoring of the FPSO hull. (author)

  13. The use of floating louvers for guiding Atlantic salmon (Salmo salar) smolts from hydroelectric turbine intakes

    International Nuclear Information System (INIS)

    Since its invention in 1955, the louver fish deflector has proven effective in diverting many fish species from power plant intake structures under both experimental and prototype situations. The cost of screening the entire water depth with louvers has deterred their more widespread use. The concept of floating louvers that would screen only surface flow was developed on the basis of the observation that salmon smolts and downstream-migrating anadromous clupeids tend to migrate near the water surface. Not only would the cost of fish screening be reduced, but a floating louver system could be used where site conditions preclude a more conventional installation. In May 1990, a prototype floating louver fish screen was tested in a power canal adjacent to the Holyoke Dam on the Connecticut River. Tests conducted with radio tagged Atlantic salmon smolts indicate that the screen is hydraulically stable in water velocities up to 1 m/s and has a guidance efficiency of 50-100%. The mean guiding efficiency over the test period was 87%. No statistical differences in guidance efficiency were detected between 1.2, 1.8, and 2.4 m louver submergence depths. 9 refs., 2 figs., 2 tabs

  14. Floating Oscillator-Embedded Triboelectric Generator for Versatile Mechanical Energy Harvesting

    Science.gov (United States)

    Seol, Myeong-Lok; Han, Jin-Woo; Jeon, Seung-Bae; Meyyappan, M.; Choi, Yang-Kyu

    2015-11-01

    A versatile vibration energy harvesting platform based on a triboelectricity is proposed and analyzed. External mechanical vibration repeats an oscillating motion of a polymer-coated metal oscillator floating inside a surrounding tube. Continuous sidewall friction at the contact interface of the oscillator induces current between the inner oscillator electrode and the outer tube electrode to convert mechanical vibrations into electrical energy. The floating oscillator-embedded triboelectric generator (FO-TEG) is applicable for both impulse excitation and sinusoidal vibration which universally exist in usual environment. For the impulse excitation, the generated current sustains and slowly decays by the residual oscillation of the floating oscillator. For the sinusoidal vibration, the output energy can be maximized by resonance oscillation. The operating frequency range can be simply optimized with high degree of freedom to satisfy various application requirements. In addition, the excellent immunity against ambient humidity is experimentally demonstrated, which stems from the inherently packaged structure of FO-TEG. The prototype device provides a peak-to-peak open-circuit voltage of 157 V and instantaneous short-circuit current of 4.6 μA, within sub-10 Hz of operating frequency. To visually demonstrate the energy harvesting behavior of FO-TEG, lighting of an array of LEDs is demonstrated using artificial vibration and human running.

  15. Floating Offshore Wind in Oregon: Potential for Jobs and Economic Impacts from Two Future Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, Tony [National Renewable Energy Lab. (NREL), Golden, CO (United States); Keyser, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tegen, Suzanne [National Renewable Energy Lab. (NREL), Golden, CO (United States); Speer, Bethany [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-05-01

    Construction of the first offshore wind power plant in the United States began in 2015, off the coast of Rhode Island, using fixed platform structures that are appropriate for shallow seafloors, like those located off of the East Coast and mid-Atlantic. However, floating platforms, which have yet to be deployed commercially, will likely need to anchor to the deeper seafloor if deployed off of the West Coast. To analyze the employment and economic potential for floating offshore wind along the West Coast, the Bureau of Ocean Energy Management (BOEM) commissioned the National Renewable Energy Laboratory (NREL) to analyze two hypothetical, large-scale deployment scenarios for Oregon: 5,500 megawatts (MW) of offshore wind deployment in Oregon by 2050 (Scenario A), and 2,900 MW of offshore wind by 2050 (Scenario B). These levels of deployment could power approximately 1,600,000 homes (Scenario A) or 870,000 homes (Scenario B). Offshore wind would contribute to economic development in Oregon in the near future, and more substantially in the long term, especially if equipment and labor are sourced from within the state. According to the analysis, over the 2020-2050 period, Oregon floating offshore wind facilities could support 65,000-97,000 job-years and add $6.8 billion-$9.9 billion to the state GDP (Scenario A).

  16. On the dynamic singularities in the control of free-floating space manipulators

    Science.gov (United States)

    Papadopoulos, E.; Dubowsky, S.

    1989-01-01

    It is shown that free-floating space manipulator systems have configurations which are dynamically singular. At a dynamically singular position, the manipulator is unable to move its end effector in some direction. This problem appears in any free-floating space manipulator system that permits the vehicle to move in response to manipulator motion without correction from the vehicle's attitude control system. Dynamic singularities are functions of the dynamic properties of the system; their existence and locations cannot be predicted solely from the kinematic structure of the manipulator, unlike the singularities for fixed base manipulators. It is also shown that the location of these dynamic singularities in the workplace is dependent upon the path taken by the manipulator in reaching them. Dynamic singularities must be considered in the control, planning and design of free-floating space manipulator systems. A method for calculating these dynamic singularities is presented, and it is shown that the system parameters can be selected to reduce the effect of dynamic singularities on a system's performance.

  17. Design and Evaluation of Stomach-Specific Drug Delivery of Domperidone using Floating Pectin Beads

    Directory of Open Access Journals (Sweden)

    K.Varun Kumar

    2013-03-01

    Full Text Available The objective of present study was to develop floating beads of Domperidone (DOM in order to increase its residence time in the stomach without contact with the mucosa, improve patient compliance and obtain improved therapeutic efficacy. They are prepared by extrusion congealing technique with pectin as a polymer. Floating beads were characterized by polymer compatibility by using FT-IR. The prepared beads were evaluated for particle size, surface morphology, buoyancy, actual drug content, entrapment efficiency and in vitro drug release. Nine formulations of DOM floating beads were formulated by using different percentage of both gas forming agent and pectin. Density of the formulated beads was found to be ranging between 0.101 and 0.182 g/cm3. The particle size was distributed between 0.6 to 1.6 mm. Buoyancy percentage was 71-87% and Drug entrapment efficiency was 54.4-64.48%. The micrometric properties were found to be good and scanning electron microscopy (SEM confirmed their hollow structure with smooth surface. The content of drug release was done by UV spectrophotometer at 284 nm. In vitro drug release of DOM, for F2 is 81.10% and for F6 is 82.6%. And the beads formulated using 0.3w/w (F2 and 0.4% w/w (F6 of pectin was more uniform in shape and exhibited maximum buoyancy. The drug content of the formulated beads was found to be satisfactory by this method. It remains in the gastric region for several hours and hence prolongs the gastric residence time of drug. From the study it was concluded that the gastro retentive drug delivery system designed as floating beads could be suitable drug delivery system for DOM.

  18. Effects of Second-Order Hydrodynamics on a Semisubmersible Floating Offshore Wind Turbine: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Bayati, I.; Jonkman, J.; Robertson, A.; Platt, A.

    2014-07-01

    The objective of this paper is to assess the second-order hydrodynamic effects on a semisubmersible floating offshore wind turbine. Second-order hydrodynamics induce loads and motions at the sum- and difference-frequencies of the incident waves. These effects have often been ignored in offshore wind analysis, under the assumption that they are significantly smaller than first-order effects. The sum- and difference-frequency loads can, however, excite eigenfrequencies of the system, leading to large oscillations that strain the mooring system or vibrations that cause fatigue damage to the structure. Observations of supposed second-order responses in wave-tank tests performed by the DeepCwind consortium at the MARIN offshore basin suggest that these effects might be more important than originally expected. These observations inspired interest in investigating how second-order excitation affects floating offshore wind turbines and whether second-order hydrodynamics should be included in offshore wind simulation tools like FAST in the future. In this work, the effects of second-order hydrodynamics on a floating semisubmersible offshore wind turbine are investigated. Because FAST is currently unable to account for second-order effects, a method to assess these effects was applied in which linearized properties of the floating wind system derived from FAST (including the 6x6 mass and stiffness matrices) are used by WAMIT to solve the first- and second-order hydrodynamics problems in the frequency domain. The method has been applied to the OC4-DeepCwind semisubmersible platform, supporting the NREL 5-MW baseline wind turbine. The loads and response of the system due to the second-order hydrodynamics are analysed and compared to first-order hydrodynamic loads and induced motions in the frequency domain. Further, the second-order loads and induced response data are compared to the loads and motions induced by aerodynamic loading as solved by FAST.

  19. Circumpolar Estimates of Isopycnal Mixing in the ACC from Argo Floats

    Science.gov (United States)

    Roach, C. J.; Balwada, D.; Speer, K. G.

    2015-12-01

    There are few direct observations of cross-stream isopycnal mixing in the interior of the Southern Ocean, yet such measurements are needed to determine the role of eddies transporting properties across the ACC, and key to progress toward testing theories of meridional overturning. In light of this we examine if it is possible to obtain estimates of mixing from Argo float trajectories. We divided the Southern Ocean into overlapping 15ο longitude bins before estimating mixing. Resulting diffusivities ranged from 300 to 3000 m2s-1, with peaks corresponding to the Scotia Sea; Kerguelen and Campbell Plateaus. Comparison of our diffusivities with previous regional studies demonstrated good agreement. Tests of the methodology in the DIMES region found that mixing from Argo floats agreed closely with mixing from RAFOS floats. To further test the method we used the Southern Ocean State Estimate velocity fields to advect particles with Argo and RAFOS float like behaviours. Stirring estimates from the particles agreed well with each other in the Kerguelen Island region, South Pacific and Scotia Sea, despite the differences in the imposed behaviour. Finally, these estimates were compared to mixing length suppression theory presented in Ferrari and Nikurashin 2010. This mixing length suppression theory quantifies horizontal diffusivity similar to Prandtl (1925), but the mixing length is suppressed in the presence of mean flows and eddy phase speeds. Our results suggest that the theory can explain both the structure and magnitude of mixing using mean flow data. An exception is near the Kerguelen and Campbell Plateaus where theory under-estimates mixing relative to our results.

  20. A novel planar vertical double-diffused metal-oxide-semiconductor field-effect transistor with inhomogeneous floating islands

    Science.gov (United States)

    Ren, Min; Li, Ze-Hong; Liu, Xiao-Long; Xie, Jia-Xiong; Deng, Guang-Min; Zhang, Bo

    2011-12-01

    A novel planar vertical double-diffused metal-oxide-semiconductor (VDMOS) structure with an ultra-low specific on-resistance (Ron,sp), whose distinctive feature is the use of inhomogeneous floating p-islands in the n-drift region, is proposed. The theoretical limit of its Ron,sp is deduced, the influence of structure parameters on the breakdown voltage (BV) and Ron,sp are investigated, and the optimized results with BV of 83 V and Ron,sp of 54 mΩ·mm2 are obtained. Simulations show that the inhomogeneous-floating-islands metal-oxide-semiconductor field-effect transistor (MOSFET) has a superior “Ron,sp/BV" trade-off to the conventional VDMOS (a 38% reduction of Ron,sp with the same BV) and the homogeneous-floating-islands MOSFET (a 10% reduction of Ron,sp with the same BV). The inhomogeneous-floating-islands MOSFET also has a much better body-diode characteristic than the superjunction MOSFET. Its reverse recovery peak current, reverse recovery time and reverse recovery charge are about 50, 80 and 40% of those of the superjunction MOSFET, respectively.

  1. A novel planar vertical double-diffused metal-oxide-semiconductor field-effect transistor with inhomogeneous floating islands

    International Nuclear Information System (INIS)

    A novel planar vertical double-diffused metal-oxide-semiconductor (VDMOS) structure with an ultra-low specific on-resistance (Ron,sp), whose distinctive feature is the use of inhomogeneous floating p-islands in the n-drift region, is proposed. The theoretical limit of its Ron,sp is deduced, the influence of structure parameters on the breakdown voltage (BV) and Ron,sp are investigated, and the optimized results with BV of 83 V and Ron,sp of 54 mΩ·mm2 are obtained. Simulations show that the inhomogeneous-floating-islands metal-oxide-semiconductor field-effect transistor (MOSFET) has a superior 'Ron,sp/BV' trade-off to the conventional VDMOS (a 38% reduction of Ron,sp with the same BV) and the homogeneous-floating-islands MOSFET (a 10% reduction of Ron,sp with the same BV). The inhomogeneous-floating-islands MOSFET also has a much better body-diode characteristic than the superjunction MOSFET. Its reverse recovery peak current, reverse recovery time and reverse recovery charge are about 50, 80 and 40% of those of the superjunction MOSFET, respectively. (interdisciplinary physics and related areas of science and technology)

  2. Preparation and Raman Spectrum of Rutile Single Crystals Using Floating Zone Method

    Institute of Scientific and Technical Information of China (English)

    GUO Xing-Yuan; XU Da-Peng; DING Zhan-Hui; SU Wen-Hui

    2006-01-01

    With anatase-type titanium dioxide as the raw materials, the rutile type titanium dioxide single crystal is prepared using the floating zone method. The results ofXRD measurement show that the grown crystal is highly crystalline with a rutile structure, which has orientation to the c-axis. The four Raman vibration characteristic peaks (143, 240, 450 and 610cm-1 ) at room temperature show that the crystalline structure of the single crystal is a typical rutile phase, meanwhile a new Raman peak at around 690cm-1 is found. The results of the Raman measurement at various temperatures for the single crystal show that the Raman frequency shifts are different.

  3. SHM of floating offshore wind turbines. Challenges and first solutions

    Energy Technology Data Exchange (ETDEWEB)

    Friedmann, Herbert; Ebert, C.; Kraemer, P. [Woelfel Beratende Ingenieure GmbH + Co. KG, Hoechberg (Germany); Frankenstein, B. [Fraunhofer IZFP, Dresden (Germany)

    2012-07-01

    The paper presents an integrated SHM-system for floater, moorings, tower, nacelle and rotor blades. Its core is based on a multivariate SHM-system for rotor blades with three different measuring techniques accompanied by appropriate signal processing approaches: - Acoustic Emission (AE) is used for identification of relative small damages at the whole blade, e.g. bursts of fibres, cracks of bonding, hits of hail and the localization of damages. - Acousto Ultrasonics (AU) provides information about relative small to big damages on the transfer path between emitter and receiver of guided waves (cracks, delamination, damages of the surface). - Operational Modal Analysis (OMA) gives information about large structural modifications e.g. changes of global stiffness, mass and damping ratios in the whole blade. The most important feature of an SHM-system, however, is not the sensor network, but the analysis capability and the decision support system reducing and interpreting measured data. The instrumentation plan of a floating wind turbine off the coast of Spain is presented. (orig.)

  4. Dynamic Behaviour of Submerged Floating Tunnels under Seismic Loadings with Different Cable Configurations

    Directory of Open Access Journals (Sweden)

    Endah Wahyuni

    2012-05-01

    Full Text Available The paper presents the dynamic behavior of a Submerged Floating Tunnel (SFT in the Seribu Archipelago crossing under seismic loadings by using the different cable configurations. The SFT is a tubular structure submerged in the water at a fixed depth, which features several advantages from the structural and environmental impact points of view. In particular, the structural system is suited for waterway crossings in seismicity zones. Its interaction with the water provides additional damping and inertia to the system. To evaluate the SFT structural response of seismic loadings, a response spectrum analyses were carried out, in which the ground multi-support excitation is considered. The investigation of the different cable system configurations were also carried out. Both static and dynamic analyses were carried to find the optimal configuration of the structural system. Although the paper has had a definitive conclusion yet, the results gave useful indications of responses of Submerged Floating Tunnels subjected to earthquake. The SFT with two cable diagonals perpendicular with SFT’s body (called Model C shows the optimal structural configuration compared with others.

  5. Modeling and analysis of floating performances of stratospheric semi-rigid airships

    Science.gov (United States)

    Li, Xiaojian; Fang, Xiande; Dai, Qiuming; Zhou, Zhanru

    2012-10-01

    In recent years, the study of semi-rigid airship has revived with the development of airships. Semi-rigid airships have some characteristics of rigid airships and non-rigid airships. Due to the flexibility of the envelope of the non-rigid airship, the variation of the temperature of the inner gas will lead to its structure deformation and affect its flight altitude. This paper develops the structural mechanics model, thermodynamic model and dynamic model of the semi-rigid airship, based on which nonlinear finite element analysis is employed for geometrically nonlinear deformation of the airship upper film in consideration of thermodynamics and structural mechanics coupling. Based on the thermal-structural interaction, the thermal characteristics and flight performances of the airship during floating flight are investigated. The 3-D solar radiation and temperature distribution of the airship skin and the temperature variation of the inner gas are presented to investigate the thermal performance of the airship, flight velocity, acceleration and flight altitude are simulated to investigate the flight performance, and the variations of the volume and pressure difference of the inner gas are calculated to provide a basis for structure design. The results of the simulation can be referenced for the design of the semi-rigid airship, and can be used for the further study on the attitude control of the airship during its floating flight.

  6. Structure and Fabrication of a Microscale Flow-Rate/Skin Friction Sensor

    Science.gov (United States)

    Chandrasekharan, Vijay (Inventor); Sells, Jeremy (Inventor); Sheplak, Mark (Inventor); Arnold, David P. (Inventor)

    2014-01-01

    A floating element shear sensor and method for fabricating the same are provided. According to an embodiment, a microelectromechanical systems (MEMS)-based capacitive floating element shear stress sensor is provided that can achieve time-resolved turbulence measurement. In one embodiment, a differential capacitive transduction scheme is used for shear stress measurement. The floating element structure for the differential capacitive transduction scheme incorporates inter digitated comb fingers forming differential capacitors, which provide electrical output proportional to the floating element deflection.

  7. The Unified Floating Point Vector Coprocessor for Reconfigurable Hardware

    Science.gov (United States)

    Kathiara, Jainik

    There has been an increased interest recently in using embedded cores on FPGAs. Many of the applications that make use of these cores have floating point operations. Due to the complexity and expense of floating point hardware, these algorithms are usually converted to fixed point operations or implemented using floating-point emulation in software. As the technology advances, more and more homogeneous computational resources and fixed function embedded blocks are added to FPGAs and hence implementation of floating point hardware becomes a feasible option. In this research we have implemented a high performance, autonomous floating point vector Coprocessor (FPVC) that works independently within an embedded processor system. We have presented a unified approach to vector and scalar computation, using a single register file for both scalar operands and vector elements. The Hybrid vector/SIMD computational model of FPVC results in greater overall performance for most applications along with improved peak performance compared to other approaches. By parameterizing vector length and the number of vector lanes, we can design an application specific FPVC and take optimal advantage of the FPGA fabric. For this research we have also initiated designing a software library for various computational kernels, each of which adapts FPVC's configuration and provide maximal performance. The kernels implemented are from the area of linear algebra and include matrix multiplication and QR and Cholesky decomposition. We have demonstrated the operation of FPVC on a Xilinx Virtex 5 using the embedded PowerPC.

  8. FORMULATION AND EVALUATION OF BILAYER FLOATING TABLET OF CARVEDILOL PHOSPHATE

    Directory of Open Access Journals (Sweden)

    Chaudhari Shilpa

    2012-09-01

    Full Text Available Gastroretentive dosage forms (GRDF enable prolonged and continuous input of the drug to the upper parts of the gastrointestinal tract and improve the bioavailability of medications those are characterized by a narrow absorption window. The aim of this study was first to develop and physico-chemically characterize an optimal single unit bilayer floating tablet for Carvedilol phosphate (CP prepared by direct compression technology secondly use Ocimum basilicum mucilage (OBM as a gelling, swelling and sustaining polymer in combination with HPMC and compared their drug release profile with marketed sustained release formulation for once-a-day administration of Carvedilol. Effect of OBM and its concentration on tablet properties such as hardness, friability, floating characteristics, swelling properties, tablet erosion and release patterns were evaluated. The release rate and floating characteristics could effectively be modified by varying ‘‘matrix forming swelling polymer, gas-generating agent’’ ratio. Drug release in optimized formulation was approximately 93.80% in 24 h in vitro and floating lag time around 5 min. The results showed floating tablets are a feasible approach for the sustained release (SR preparation of CP.

  9. KLT-20 reactor for a floating power unit. Annex VI

    International Nuclear Information System (INIS)

    The KLT-20 reactor installation is being designed by the Experimental Design Bureau of Machine Building (OKBM, Nizhny Novgorod) as a power source for floating nuclear power plants (NPPs). At present, the activities are most advanced for the project of a pilot floating heat and power plant with the KLT-40S reactor installations, advanced analogues of the commercial KLT-40 reactors of the Russian icebreaker fleet. For the KLT-40S, detailed design of the reactor unit and floating power unit has been developed and approved; the Rostechnadzor of Russia license for plant siting and floating power unit construction in Severodvinsk (Russian Federation) has been obtained. The KLT-20, based on a pressurized light-water reactor of 20 MW(e), is a two-loop modification of the KLT-40S reactor with several improvements in the main equipment and a long-refuelling interval, achieved with the enrichment of less than 20%. The reactor design with a long refuelling interval was developed based on the engineering solutions of the pilot KLT-40S reactor installation; different from it, the KLT-20 provides for no on-site refuelling. The refuelling, radioactive waste management and repairs of a floating NPP with the KLT-20 would be performed at special maintenance centres. The infrastructure of nuclear ship maintenance centres in Russia could be used for these purposes

  10. A floating island for recovering oil and gas

    Energy Technology Data Exchange (ETDEWEB)

    Beketov, YuA.; Dorofeyev, D.I.

    1984-01-01

    The purpose of the invention is to increase the stability of operation of a floating island for extracting oil and gas. The stated purpose is achieved by the fact that on the floating island for extracting oil and gas, which contains a floating torus shaped body with a central axial opening and an anchoring and stabilizing device equipped with an installation for extracting oil and gas which is located in an operational chamber submerged under water under the central axial opening of the cited body and connected with it, as well as a rock crushing device, the torus shaped body is made with vertical grooves positioned on its internal annular wall, two opposed abutting subassemblies and two telescopic levers. The operational chamber is drop shaped, is connected with the body by means of the cited telescopic levers and is equipped with two abutment ports located on its lateral sides which interact with the abutment subassemblies, and with vertical guides which interact with the grooves on the annular wall. Moreover, the ice crushing device is made with torpedo devices evenly disposed along the external perimeter of the floating torus shaped body. The proposed floating island for extracting oil and gas has high stability in operation in stormy conditions and on the shelf of the seas of the Artic Ocean.

  11. Preparation and evaluation of gastroretentive floating tablets of Silymarin.

    Science.gov (United States)

    Garg, Rajeev; Gupta, Ghanshyam Das

    2009-06-01

    The present study performed by preparation and evaluation of floating tablets of Silymarin as model drug for prolongation of gastric residence time. Floating effervescent tablets were formulated by various materials like hydroxypropyl methylcellulose (HPMC) K 4M, K 15M, psyllium husk, swelling agent as crospovidone and microcrystalline cellulose and gas generating agent like sodium bicarbonate and citric acid and evaluated for floating properties, swelling characteristics and in vitro drug release studies. Floating noneffervescent tablets were prepared by polypropylene foam powder and different matrix forming polymers like HPMC K 4M, Carbopol 934P, xanthan gum and sodium alginate. In vitro drug release studies were performed and drug release kinetics evaluated using the linear regression method was found to follow both the Higuchi and the Korsemeyer and Peppas equation. The drug release mechanism was found fickian type in most of the formulations. The developed floating tablets of Silymarin may be used in clinic for prolonged drug release for at least 24 h, thereby improving the bioavailability and patient compliance. PMID:19483331

  12. Propagation characteristics of dust-acoustic waves in presence of a floating cylindrical object in the DC discharge plasma

    Science.gov (United States)

    Choudhary, Mangilal; Mukherjee, S.; Bandyopadhyay, P.

    2016-08-01

    The experimental observation of the self-excited dust acoustic waves (DAWs) and its propagation characteristics in the absence and presence of a floating cylindrical object is investigated. The experiments are carried out in a direct current (DC) glow discharge dusty plasma in a background of argon gas. Dust particles are found levitated at the interface of plasma and cathode sheath region. The DAWs are spontaneously excited in the dust medium and found to propagate in the direction of ion drift (along the gravity) above a threshold discharge current at low pressure. Excitation of such a low frequency wave is a result of the ion-dust streaming instability in the dust cloud. Characteristics of the propagating dust acoustic wave get modified in the presence of a floating cylindrical object of radius larger than that of the dust Debye length. Instead of propagation in the vertical direction, the DAWs are found to propagate obliquely in the presence of the floating object (kept either vertically or horizontally). In addition, a horizontally aligned floating object forms a wave structure in the cone shaped dust cloud in the sheath region. Such changes in the propagation characteristics of DAWs are explained on the basis of modified potential (or electric field) distribution, which is a consequence of coupling of sheaths formed around the cylindrical object and the cathode.

  13. Improvement of Ron under AC Operation of Floating Island and Thick Bottom Oxide Trench Gate MOSFET (FITMOS)

    Science.gov (United States)

    Takaya, Hidefumi; Miyagi, Kyosuke; Hamada, Kimimori

    A MOSFET structure called a FITMOS (Floating Island and Thick Bottom Oxide Trench Gate MOSFET) that exhibits a record low loss in the 60V breakdown voltage (BVdss) range has been successfully developed. The following improvements achieved progress in the characteristic of FITMOS. (1) At the time of AC operation, the charges in the floating P islands that are a feature of the floating type device become greater, thereby increasing the on-resistance (Ron) due to the JFET effect. This issue was solved by forming passive hole gates in the end walls of the trenches. The Ron under AC operation is equivalent to the Ron under DC operation. This paper clarified the influence of the passive hole gate diffusion layer shape and the impurity concentration to BVdss and AC operation. (2) The trade-off of BVdss and Ron has been improved by making the floating island into an elliptical form. A BVdss of 83V and a specific on-resistance (RonA) of 36mΩmm2 were obtained.

  14. The effects of second-order hydrodynamics on a semisubmersible floating offshore wind turbine

    International Nuclear Information System (INIS)

    The objective of this paper is to assess the second-order hydrodynamic effects on a semisubmersible floating offshore wind turbine. Second-order hydrodynamics induce loads and motions at the sum- and difference-frequencies of the incident waves. These effects have often been ignored in offshore wind analysis, under the assumption that they are significantly smaller than first-order effects. The sum- and difference-frequency loads can, however, excite eigenfrequencies of a floating system, leading to large oscillations that strain the mooring system or vibrations that cause fatigue damage to the structure. Observations of supposed second-order responses in wave-tank tests performed by the DeepCwind consortium at the Maritime Research Institute Netherlands (MARIN) offshore basin suggest that these effects might be more important than originally expected. These observations inspired interest in investigating how second-order excitation affects floating offshore wind turbines and whether second-order hydrodynamics should be included in offshore wind simulation tools like FAST. In this work, the effects of second-order hydrodynamics on a floating semisubmersible offshore wind turbine are investigated. Because FAST is currently unable to account for second-order effects, a method to assess these effects was applied in which linearized properties of the floating wind system derived from FAST (including the 6x6 mass and stiffness matrices) are used by WAMIT to solve the first- and second-order hydrodynamics problems in the frequency domain. The method was applied to the Offshore Code Comparison Collaboration Continuation OC4-DeepCwind semisubmersible platform, supporting the National Renewable Energy Laboratory's 5-MW baseline wind turbine. In this paper, the loads and response of the system caused by the second-order hydrodynamics are analysed and compared to the first-order hydrodynamic loads and induced motions in the frequency domain. Further, the second

  15. Seismic monitoring in the oceans by autonomous floats

    Science.gov (United States)

    Sukhovich, Alexey; Bonnieux, Sébastien; Hello, Yann; Irisson, Jean-Olivier; Simons, Frederik J.; Nolet, Guust

    2015-08-01

    Our understanding of the internal dynamics of the Earth is largely based on images of seismic velocity variations in the mantle obtained with global tomography. However, our ability to image the mantle is severely hampered by a lack of seismic data collected in marine areas. Here we report observations made under different noise conditions (in the Mediterranean Sea, the Indian and Pacific Oceans) by a submarine floating seismograph, and show that such floats are able to fill the oceanic data gap. Depending on the ambient noise level, the floats can record between 35 and 63% of distant earthquakes with a moment magnitude M>=6.5. Even magnitudes <6.0 can be successfully observed under favourable noise conditions. The serendipitous recording of an earthquake swarm near the Indian Ocean triple junction enabled us to establish a threshold magnitude between 2.7 and 3.4 for local earthquakes in the noisiest of the three environments.

  16. Research of design challenges and new technologies for floating LNG

    Directory of Open Access Journals (Sweden)

    Lee Dong-Hyun

    2014-06-01

    Full Text Available With the rate of worldwide LNG demand expected to grow faster than that of gas demand, most major oil companies are currently investing their resources to develop floating LNG-FLNG (i.e. LNG FSRU and LNG FPSO. The global Floating LNG (FLNG market trend will be reviewed based on demand and supply chain relationships. Typical technical issues associated with FLNG design are categorized in terms of global performance evaluation. Although many proven technologies developed through LNG carrier and oil FPSO projects are available for FLNG design, we are still faced with several technical challenges to clear for successful FLNG projects. In this study, some of the challenges encountered during development of the floating LNG facility (i.e. LNG FPSO and FSRU will be reviewed together with their investigated solution. At the same time, research of new LNG-related technologies such as combined containment system will be presented.

  17. Orthogonal test and experimental study on fire floating pump

    International Nuclear Information System (INIS)

    In order to develop high efficiency fire floating pump, 250YYB-250 fire floating pump was taken as an example. The orthogonal experiment of L9 (34), which contains factors with three levels of blade numbers of impeller, outlet angle, impeller fold-angle, was performed to design nine types of impellers. Numerical simulation of whole flow field based on Fluent was adopted to perform an orthogonal test, the order of geometric parameters affects the performance of fire floating pump with complex impeller. The best design scheme for pump model was acquired. Meanwhile, the optimized design scheme was determined, and corresponding test was carried out. It demonstrated that the efficiency of the final optimal design model pump at rated flow point is of 85%. The efficiency is higher than the national standards, which verified the feasibility of the method of orthogonal design in pump design

  18. Feasibility study of a nuclear floating island (NUFIS)

    International Nuclear Information System (INIS)

    Under the present oil demand/supply situation, oil consumption must be reduced in Japan, implying the reliance on nuclear energy in future. The siting for nuclear power plants is limited, however, because of the dense population; there must emerge a new concept in this connection. Feasibility of a nuclear floating island (NUFIS) has been studied. The NUFIS is located about 20 km offshore with sea depth about 150 m and has a 1,200 MWe PWR plant on a 140 m x 140 m floating platform, with displacement about 298,000 tons. It is technologically feasible, and the platform is stable enough to build the power plant and its associated facilities on it. It is possible to construct a nuclear floating center offshore of Japan, which comprises VHTR, FBR, fuel reprocessing and fabrication plants. (author)

  19. Research of design challenges and new technologies for floating LNG

    Science.gov (United States)

    Lee, Dong-Hyun; Ha, Mun-Keun; Kim, Soo-Young; Shin, Sung-Chul

    2014-06-01

    With the rate of worldwide LNG demand expected to grow faster than that of gas demand, most major oil companies are currently investing their resources to develop floating LNG-FLNG (i.e. LNG FSRU and LNG FPSO). The global Floating LNG (FLNG) market trend will be reviewed based on demand and supply chain relationships. Typical technical issues associated with FLNG design are categorized in terms of global performance evaluation. Although many proven technologies developed through LNG carrier and oil FPSO projects are available for FLNG design, we are still faced with several technical challenges to clear for successful FLNG projects. In this study, some of the challenges encountered during development of the floating LNG facility (i.e. LNG FPSO and FSRU) will be reviewed together with their investigated solution. At the same time, research of new LNG-related technologies such as combined containment system will be presented.

  20. Numerical simulation of a floating buoy in surface waves

    Science.gov (United States)

    Altazin, Thomas; Golay, Frédéric; Fraunié, Philippe

    2016-04-01

    A numerical method based on volumic penalization is developed to track a floating body in a two phase flows (air and water). Fast computations on parallel computer are performed thanks to an adaptative mesh refinement following a numerical entropy criterion together with a variable time step depending on the mesh size. Applications concern the motion of a floating buoy in a surface wave field and the induced perturbation of the wave and atmospheric fields by the buoy. Presented cases concern a breaking wave and a second order Stokes wave as initial conditions. Acknowledgements : This research was supported by the Modtercom and CHEF projects of Region PACA, when applications on windage of floating buoys are related to the SUBCORAD LEFE-INSU project.

  1. Formulation and evaluation of glipizide floating-bioadhesive tablets

    Directory of Open Access Journals (Sweden)

    Jayvadan K. Patel

    2010-10-01

    Full Text Available The purpose of this study was formulation and in vitro evaluation of floating-bioadhesive tablets to lengthen the stay of glipizide in its absorption area. Effervescent tablets were made using chitosan (CH, hydroxypropyl methylcellulose (HPMC, carbopolP934 (CP, polymethacrylic acid (PMA, citric acid, and sodium bicarbonate. Tablets with 5% effervescent base had longer lag time than 10%. The type of polymer had no significant effect on the floating lag time. All tablets floated atop the medium for 23-24 hr. Increasing carbopolP934 caused higher bioadhesion than chitosan (p < 0.05. All formulations showed a Higuchi, non-Fickian release mechanism. Tablets with 10% effervescent base, 80% CH/20% HPMC, or 80% CP/20% PMA seemed desirable.

  2. Orthogonal test and experimental study on fire floating pump

    Science.gov (United States)

    Liu, J. R.; Zheng, J. F.; Fu, D. P.; Wang, P.

    2013-12-01

    In order to develop high efficiency fire floating pump, 250YYB-250 fire floating pump was taken as an example. The orthogonal experiment of L9 (34), which contains factors with three levels of blade numbers of impeller, outlet angle, impeller fold-angle, was performed to design nine types of impellers. Numerical simulation of whole flow field based on Fluent was adopted to perform an orthogonal test, the order of geometric parameters affects the performance of fire floating pump with complex impeller. The best design scheme for pump model was acquired. Meanwhile, the optimized design scheme was determined, and corresponding test was carried out. It demonstrated that the efficiency of the final optimal design model pump at rated flow point is of 85%. The efficiency is higher than the national standards, which verified the feasibility of the method of orthogonal design in pump design.

  3. Preparation and evaluation of ciprofloxzacin hydrochloride floating oral delivery system

    International Nuclear Information System (INIS)

    A sustained release system for ciprofloxacin hydrochloride designed to increase its residence time in the stomach was achieved through the preparation of floating microparticles by the solvent diffusion technique, using Eudragit S 100 and Eudragit RL 100 polymers. Eight different ratios of Eudragit mixture were used for the formulation, all of which showed good flow properties and packability. The drug retained in the microparticles decreased with increase in Eudragit RL 100 content, whereas, the floating ability increased with increase in weight ratio of Eudragit RL 100. There were differences between the formulations as to their appearance and size distribution. Fourier transform infrared (FTIR) spectrophotometric study confirmed intactness of drug in formulations. The formulation containing ES: ERL in a ratio 1.5:1 exhibited high percentage of floating particles with a controlled release of drug in 0.1N HCL. (author)

  4. A novel, aerosol-nanocrystal floating-gate device for non-volatile memory applications

    OpenAIRE

    De Blauwe, J. W.; Ostraat, M. L.; Green, M. L.; Weber, G.; Sorsch, T.; Kerber, A.; Klemens, F.; Cirelli, R.; Ferry, E.; Grazul, J. L.; Baumann, F.; Kim, Y.; Mansfield, W.; Bude, J.; Lee, J. T. C.

    2000-01-01

    This paper describes the fabrication, and structural and electrical characterization of a new, aerosol-nanocrystal floating-gate FET, aimed at non-volatile memory (NVM) applications. This aerosol-nanocrystal NVM device features program/erase characteristics comparable to conventional stacked gate NVM devices, excellent endurance (>l0^5 P/E cycles), and long-term non-volatility in spite of a thin bottom oxide (55-60Å). In addition, a very simple fabrication process makes this aerosol-nanocryst...

  5. Dynamic equations for curved submerged floating tunnel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In virtue of reference Cartesian coordinates, geometrical relations of spatial curved structure are presented in orthogonal curvilinear coordinates. Dynamic equations for helical girder are derived by Hamilton principle. These equations indicate that four generalized displacements are coupled with each other. When spatial structure degenerates into planar curvilinear structure, two generalized displacements in two perpendicular planes are coupled with each other. Dynamic equations for arbitrary curvilinear structure may be obtained by the method used in this paper.

  6. ROLE OF NATURAL POLYMERS USED IN FLOATING DRUG DELIVERY SYSTEM

    Directory of Open Access Journals (Sweden)

    Singh Amit Kumar

    2012-06-01

    Full Text Available Floating drug delivery system is the form of gastro-retentive drug delivery system that controls the kinetic release rate of a drug to a specific site for its pharmacological action. These are achieved by use of various polymeric substance including natural polymers such as Guar Gum, Xanthan Gum, Gellan Gum etc. This delivery system prolongs the retention time of the drug in the stomach as compared to conventional dosage forms. The present article highlights the use of polymers for the formulation of the floating drug delivery system especially with natural polymers.

  7. Towards a Completion of Archimedes' Treatise on Floating Bodies

    CERN Document Server

    Girstmair, Kurt

    2007-01-01

    In his treatise on floating bodies Archimedes determines the equilibrium positions of a floating paraboloid segment, but only in the case when the basis of the segment is either completely outside of the fluid or completely submerged. Here we give a mathematical model for the remaining case, i.e., two simple conditions which describe the equilibria in closed form. We provide tools for finding all equilibria in a reliable way and for the classification of these equilibria. This paper can be considered as a continuation of a recent article of Rorres.

  8. Wind resource assessment method for floating deep offshore wind turbines

    OpenAIRE

    Estanqueiro, Ana; Couto, A.; Rodrigues, L.; Marujo, R.

    2014-01-01

    This study presents a new methodology for the assessment of the wind energy resource at deep offshore locations where the use of floating wind turbines is foreseen. The wind resource assessment methodology developed follows the principles used by IEC 61400-12-1 standard in general and proposes the use of experimental data from a floating light detection and ranging (LIDAR) system on a deep offshore region – that assumes the role of the ‘temporary mast’ – and a coastal meteorological mast inst...

  9. Surface characterization of float glass using Indus-I

    International Nuclear Information System (INIS)

    The production of window glass is through float technique, which causes diffusion of tin into glass surface in contact with molten tin. Using Indus-I storage ring, angle dependent reflectivity of the top and the bottom surface of float glass were measured in vacuum ultra violet/soft x-ray region. Remarkable differences in refractive index were observed between the two sides. Surface impurities on the top and bottom surface were quantified using grazing incidence x-ray fluorescence measurements. The higher optical density of the bottom side was attributed fractional enrichment of iron along with tin diffusion. (author)

  10. Wave Energy, Lever Operated Pivoting Float LOPF Study

    DEFF Research Database (Denmark)

    Margheritini, Lucia

    The fully instrumented Resen Waves Lever Operated Pivoting Float LOPF wave energy buoy model has gone through the first stage of testing in regular waves in scale 1:25 of the North Sea wave conditions, in the 3D deep wave basin at the Hydraulic and Coastal Engineering Laboratory of Aalborg...... for maximum energy output in regular as well as irregular waves. During storms the buoy pivots and streamlines itself to minimize loads on the mooring line. A conservative estimate shows that a full scale system for North Sea conditions has a float size width of 15 m that will, with 60% generator...

  11. Vegetation, substrate and hydrology in floating marshes in the Mississippi river delta plain wetlands, USA

    Science.gov (United States)

    Sasser, C.E.; Gosselink, J.G.; Swenson, E.M.; Swarzenski, C.M.; Leibowitz, N.C.

    1996-01-01

    In the 1940s extensive floating marshes (locally called 'flotant') were reported and mapped in coastal wetlands of the Mississippi River Delta Plain. These floating marshes included large areas of Panicum hemitomon-dominated freshwater marshes, and Spartina patens/Scirpus olneyi brackish marshes. Today these marshes appear to be quite different in extent and type. We describe five floating habitats and one non-floating, quaking habitat based on differences in buoyancy dynamics (timing and degree of floating), substrate characteristics, and dominant vegetation. All floating marshes have low bulk density, organic substrates. Nearly all are fresh marshes. Panicum hemitomon floating marshes presently occur within the general regions that were reported in the 1940's by O'Neil, but are reduced in extent. Some of the former Panicum hemitomon marshes have been replaced by seasonally or variably floating marshes dominated, or co-dominated by Sagittaria lancifolia or Eleocharis baldwinii. ?? 1996 Kluwer Academic Publishers.

  12. Causes, trends, and policy of population migration and the floating population.

    Science.gov (United States)

    Cai, F

    1996-01-01

    This study provides a discussion of migration theory, a description of the main characteristics of migrants and floating population in China, and a migration impact assessment and potential social policy directions. It is argued that the impetus for migration in China was the population distribution pattern and an uneven industrial structure that favored heavy industry. Another factor affecting migration is the gap in income between urban and rural areas, which has widened since reforms in the mid-1980s. The author finds the Todaro or the Harris-Todaro theories inappropriate for understanding migration in developing countries and flawed. Evidence about migrants' characteristics suggest that migration in China was part of a process governed by the laws of economic growth and market development. Legal migrants are defined as those who legally migrated according to the household registration system. China's development strategy during the 1950s relied on growth of capital-intensive heavy industry. The cost was underwritten by adoption of a price system that shifted the price of products in order to lower the cost of heavy industrial development. During 1952-78, agricultural output dropped sharply, but the employment structure changed very little and the rate of urbanization changed slightly. Regional inequality was obvious by 1978. As reform progressed, patterns emerged that favored eastern coastal development. Microlevel reform outdistanced macrolevel reform. Obstacles to migration were reduced: the breakup of the commune system and changes in the urban food supply system and housing. In 1990 there were 34.128 million migrants, of which 32.42% were interprovincial and 42.99% involved job-related shifts. In 1992, 8.1% of urban population were not registered; 94.909 million were floating population. Cities have established policies to match the size of the floating population to the current carrying capacity. PMID:12291970

  13. Experimental study on influence of pitch motion on the wake of a floating wind turbine model

    Science.gov (United States)

    Rockel, Stanislav; Cal, Raul Bayoan; Peinke, Joachim; Hoelling, Michael

    2013-11-01

    Wind energy has become a major contributor to energy from renewable sources and is still demanded to increase its portion to the overall energy supply. Offshore wind energy was found to have the highest potential to fulfill these demands, due to better and steadier wind conditions found on seas. Offshore wind turbines which have been installed lately use monopiles as foundations and are feasible in shallow water up to a depth of 50m. Such shallow areas are rare and often exploited, so floating support structures for offshore wind turbines in deep water are possible solutions. The additional degrees of freedom of a floating support structure will influence the aerodynamics at the rotor and its wake. Wind tunnel experiments were performed using a classical fixed turbine model and a streamwise oscillating turbine in free pitch motion. For both cases the turbines were operated under same inflow conditions and wakes up to 7 rotor diameters were measured using 2D-3C stereographic particle image velocimetry (SPIV). The obtained data was statistically analyzed and a direct comparison of the wake of the fixed and oscillating turbine was performed. Our results show that inclinations and oscillations of the turbine have a strong impact on the structure of the wake and its development.

  14. The Design of a Low Power Floating Gate Based Phase Frequency Detector and Charge Pump Implementation

    OpenAIRE

    Md. Monirul Islam; Ankit Shivhare

    2013-01-01

    A simple new architecture of phase frequency detector with low power and low phase noise is presented in this paper. The proposed phase frequency detector is based on floating gate, consist of 4 transistors including one floating gate pMOS and one floating gate nMOS constructed with two GDI (gate diffusion input) cells and maintain main characteristics of conventional phase frequency detector in 180 nm technology. Floating gate based methodology reduced the power of phase frequenc...

  15. FPGA Implementation of Double Precision Floating Point Multiplier using Xilinx Coregen Tool

    OpenAIRE

    Sukhvir Kaur; Parminder Singh Jassal

    2013-01-01

    Floating point arithmetic is widely used in many areas, especially scientific computation and signal processing. The main applications of floating points today are in the field of medical imaging, biometrics, motion capture and audio applications. The IEEE floating point standard defines both single precision and double precision formats. Multiplication is a core operation in many signal processing computations, and as such efficient implementation of floating point multipliers is an importan...

  16. Effects of vegetation, season and temperature on removal pollutants in experimental floating treatment wetlands

    OpenAIRE

    Van de Moortel, Annelies; Meers, Erik; Niels DE PAUW; Tack, Filip

    2010-01-01

    The research and interest towards the use of constructed floating wetlands for (waste)water treatment is emerging as more treatment opportunities are marked out, and the technique is applied more often. To evaluate the effect of a floating macrophyte mat and the influence of temperature and season on physico-chemical changes and removal, two constructed floating wetlands (CFWs), including a floating macrophyte mat, and a control, without emergent vegetation, were built. Raw domestic wastewate...

  17. Behavior of Flotsam in the California Current System Utilizing Surface Drift of RAFOS Floats

    OpenAIRE

    Gates, Dallas Cody

    2012-01-01

    The patterns of surface drift of eighty-nine undrogued RAFOS floats in the California Current System have been studied. The floats were launched in the California Undercurrent during 19922010 and were tracked by the ARGOS system when they surfaced at the end of their subsurface mission. The surface drift of these floats was typically equatorward in the California Current. However, some floats moved poleward into the Subpolar Gyre, and others drifted westward into the North Equatorial Current....

  18. Formulation, Evaluation and Optimization of Bilayer Floating Tablet of Repaglinide and Glipizide

    OpenAIRE

    SOLANKI PRIYANKA DHARMENDRASINH

    2012-01-01

    Objective: The aim of the present research was to develop a bilayer floating drug delivery system. That contains two layers immediate release layer and sustain release layer. First immediate release layer quickly releases drugs and attains onset of action, subsequently floating sustained release layer floats over gastric fluid and releases the drug in sustained or controlled manner. Experimental Work: In bilayer tablet formulation, the floating sustained release layer was compressed and immed...

  19. Teaching and Learning in an 80-Hour Work Week: A Novel Day-float Rotation for Medical Residents

    OpenAIRE

    Wong, Jeffrey G.; Holmboe, Eric S; Huot, Stephen J.

    2004-01-01

    The 80-hour workweek limit for residents provides an opportunity for residency directors to creatively innovate their programs. Our novel day-float rotation augmented both the educational structure within the inpatient team setting and the ability for house staff to complete their work within the mandated limits. Descriptive evaluation of the rotation was performed through an end-of-rotation questionnaire. The average length of the ward residents’ work week was quantified before and after the...

  20. 40 CFR 65.43 - Fixed roof with an internal floating roof (IFR).

    Science.gov (United States)

    2010-07-01

    ... failures, the internal floating roof, and the seal through manholes and roof hatches on the fixed roof no...) of this section: (i) Visually inspect for IFR type B failures, the internal floating roof, the... internal floating roof and the other components as specified in the following: (A) For IFR type A...

  1. FORMULATION AND EVALUATION OF FLOATING TABLETS OF TIZANIDINE HYDROCHLORIDE

    Directory of Open Access Journals (Sweden)

    Adimoolam Senthil

    2011-08-01

    Full Text Available The objective of the present investigation was to develop floating matrix tablets of tizanidine hydrochloride for prolongation of gastric residence time in order to overcome its low bioavailability (34–40% and short biological half life (4.2 h. Tizanidine hydrochloride floating tablets were prepared by the direct compression method, using different viscosity grades of hydroxypropylmethylcellulose (HPMC K4M and K15M. Tizanidine hydrochloride is an orally administered prokinetic agent that facilitates or restores motility throughout the length of the gastrointestinal tract. Tablets were evaluated for various physical parameters and floating properties. Further, tablets were studied for in-vitro drug release characteristics in 12 hours. Drug release from floating matrix tablets was sustained over 12 h with buoyant properties. DSC study revealed that there was no drug and excipient interaction. Based on the release kinetics, all formulations best fitted the Higuchi, first-order model and non-Fickian as the mechanism of drug release. The optimized formulation (F9 released 75% of drug at the end of 10 hours by in-vitro release study.

  2. A Floating Offshore Wind Turbine in Extreme Wave Conditions

    DEFF Research Database (Denmark)

    Wehmeyer, Christof

    , i.e. Hm0, Tp and peak enhancement factors, based on cyclonic storm conditions (Wehmeyer et al., 2012). 2. Based on Wehmeyer et al. (2012), a physical model test campaign was drafted, where an industry inspired floating offshore wind turbine was tested (Wehmeyer et al., 2013). 3. A comparison of...

  3. Life cycle assessment of a floating offshore wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Weinzettel, Jan [Department of Electrotechnology, Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, Praha 166 27 (Czech Republic); Charles University in Prague Environment Center, U Krize 8, Prague 158 00 (Czech Republic); Reenaas, Marte; Solli, Christian [Industrial Ecology Programme, Norwegian University of Science and Technology (NTNU), 7491 Trondheim (Norway); Hertwich, Edgar G. [Industrial Ecology Programme, Norwegian University of Science and Technology (NTNU), 7491 Trondheim (Norway); Department of Energy and Process Engineering, Norwegian University of Science and Technology (NTNU), 7491 Trondheim (Norway)

    2009-03-15

    A development in wind energy technology towards higher nominal power of the wind turbines is related to the shift of the turbines to better wind conditions. After the shift from onshore to offshore areas, there has been an effort to move further from the sea coast to the deep water areas, which requires floating windmills. Such a concept brings additional environmental impact through higher material demand. To evaluate additional environmental burdens and to find out whether they can be rebalanced or even offset by better wind conditions, a prospective life cycle assessment (LCA) study of one floating concept has been performed and the results are presented in this paper. A comparison with existing LCA studies of conventional offshore wind power and electricity from a natural gas combined cycle is presented. The results indicate similar environmental impacts of electricity production using floating wind power plants as using non-floating offshore wind power plants. The most important stage in the life cycle of the wind power plants is the production of materials. Credits that are connected to recycling these materials at the end-of-life of the power plant are substantial. (author)

  4. A global inventory of small floating plastic debris

    NARCIS (Netherlands)

    Sebille, van Erik; Wilcox, Chris; Lebreton, Laurent; Maximenko, Nikolai; Hardesty, Britta Denise; Franeker, van J.A.; Eriksen, Marcus; Siegel, David; Galgani, F.; Law, Kara Lavender

    2015-01-01

    Microplastic debris floating at the ocean surface can harm marine life. Understanding the severity of this harm requires knowledge of plastic abundance and distributions. Dozens of expeditions measuring microplastics have been carried out since the 1970s, but they have primarily focused on the
    N

  5. Addendum to: Capillary floating and the billiard ball problem

    OpenAIRE

    Gutkin, Eugene

    2012-01-01

    We compare the results of our earlier paper on the floating in neutral equilibrium at arbitrary orientation in the sense of Finn-Young with the literature on its counterpart in the sense of Archimedes. We add a few remarks of personal and social-historical character.

  6. 14 CFR 25.535 - Auxiliary float loads.

    Science.gov (United States)

    2010-01-01

    ..., the prescribed water loads may be distributed over the float bottom to avoid excessive local loads... position and with no slipstream effect; W=seaplane design landing weight in pounds; βS=angle of dead rise... appropriate position and with no slipstream effect; and g=acceleration due to gravity (ft./sec.2). (g)...

  7. Udpegning af potentielle sorte pletter via floating car data

    DEFF Research Database (Denmark)

    Splid Svendsen, Martin; Tradisauskas, Nerius; Lahrmann, Harry

    2008-01-01

    Formålet med dette paper er at undersøge, om det er muligt at udpege potentielle sorte pletter via floating car data. Der er i projektet udført teoretiske litteraturstudier for at skabe et grundlag for det senere analysearbejde, som danner baggrund for analysearbejdet. Dataene stammer fra Aalborg...

  8. Experiment study of the motion of the floating offshore turbine

    Science.gov (United States)

    Chuang, Tzu-Ching; Hsu, Wen-Yang; Yang, Ray-Yeng; Chen, Yang-Yi

    2016-04-01

    Recently the wind industry moved to offshore areas. The floating wind turbine combined the platform and the mooring system. This research focuses on studying the motion of the floating offshore turbine with a mooring system. The platform, which was developed by the Ship and Ocean Industries R&D Center, had been test in a wave-wind flume in the Tainan Hydraulics Laboratory by using a 1:50 Froude scaling model. In the experiment, the floating offshore turbine was placed in a water flume and exposed to periodic waves at frequencies ranging from 0.22 rad/s - 0.875 rad/s, the wave amplitude is about 2.5 meter, and with the different pretension of the mooring lines. The experiment includes the measurement of damping coefficient from the free decay test and the dynamic response in a sea state. This research compares the motion of the floating offshore turbine with the different pretension of the mooring lines, and the model provides comprehensive data for the operational, design, and survival seas states, as well as the calibration and improvement of the existing design and performance of numerical models.

  9. Automated ''float'' method for determination of densities of molten salts

    DEFF Research Database (Denmark)

    Andreasen, Helge A.; Bjerrum, Niels; Foverskov, Carl Erik

    1977-01-01

    A new system for measuring densities of molten salt systems is described. The system consists of an accurate metal block furnace, the temperature of which can be changed linearly in time, a fused quartz tube containing quartz floats loaded with a ferromagnetic material, a differential transformer....... Review of Scientific Instruments is copyrighted by The American Institute of Physics....

  10. The floating knee: epidemiology, prognostic indicators & outcome following surgical management

    Directory of Open Access Journals (Sweden)

    Yesupalan Rajam S

    2007-11-01

    Full Text Available Abstract Background Floating Knee injuries are complex injuries. The type of fractures, soft tissue and associated injuries make this a challenging problem to manage. We present the outcome of these injuries after surgical management. Methods 29 patients with floating knee injuries were managed over a 3 year period. This was a prospective study were both fractures of the floating knee injury were surgically fixed using different modalities. The associated injuries were managed appropriately. Assessment of the end result was done by the Karlstrom criteria after bony union. Results The mechanism of injury was road traffic accident in 27/29 patients. There were 38 associated injuries. 20/29 patients had intramedullary nailing for both fractures. The complications were knee stiffness, foot drop, delayed union of tibia and superficial infection. The bony union time ranged from 15 – 22.5 weeks for femur fractures and 17 – 28 weeks for the tibia. According to the Karlstrom criteria the end results were Excellent – 15, Good – 11, Acceptable – 1 and Poor – 3. Conclusion The associated injuries and the type of fracture (open, intra-articular, comminution are prognostic indicators in the Floating knee. Appropriate management of the associated injuries, intramedullary nailing of both the fractures and post operative rehabilitation are necessary for good final outcome.

  11. Floating Power Supply for Specimen Bias in Scanning Electron Microscope

    Czech Academy of Sciences Publication Activity Database

    Horáček, Miroslav; Zobač, Martin; Vlček, Ivan

    Brno: Tribun EU, 2009. s. 24. ISBN 978-80-7399-739-7. [Mikroskopia 2009. 25.03.2009-26.03.2009, Stará Lesná] R&D Projects: GA AV ČR IAA100650803 Institutional research plan: CEZ:AV0Z20650511 Keywords : floating power supply * scanning electron microscope Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  12. The sheath effect on the floating harmonic method

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jaewon; Kim, Kyung-Hyun; Chung, Chin-Wook, E-mail: joykang@hanyang.ac.kr [Department of Electrical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)

    2015-12-15

    The floating harmonic method biases sinusoidal voltage to a probe sheath, and as its response, harmonic currents can be obtained. These currents can be used to determine the plasma parameters. However, different shapes of probes have different shapes of sheaths that can affect the diagnostic results. However, no research has been done on the sheath effect on the floating harmonic method. Therefore, we investigate the effect of the sheath during floating harmonic diagnostics by comparing cylindrical and planar probes. While the sinusoidal voltages were applied to a probe, because the sheath oscillated, the time variant ion current and their harmonic currents were added to the electron harmonic currents. In the floating harmonic method, the harmonic currents are composed of only the electron harmonic currents. Therefore, the ion harmonic currents affect the diagnostic results. In particular, the electron temperature obtained by the small probe tip was higher than that of the large probe tip. This effect was exacerbated when the ratio of the probe tip radius to the sheath length was smaller.

  13. FEA for designing of floating raft shock-resistant system

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ying-long; HE Lin; HUANG Ying-yun; WANG Yu

    2003-01-01

    Choosing the equipment with good shock-resistant performance and taking shock protection measures while designing the onboard settings, the safety of onboard settings can be assured when warships, especially submarine subjected to non-contact underwater explosion, that is, these means can be used to limit the rattlespace (i.e., the maximum displacement of the equipment relative to the base) and the peak acceleration experienced by the equipment. Using shock-resistant equipments is one of shock protection means. The shock-resistant performance of the shock-resistant equipments should be verified in the design phase of the equipments. The FEA (finite element analysis) software, for example, MSC.NASTRAN(R), can be used to verify the shock-resistant performance. MSC.PATRAN(R) and MSC.NASTRAN are used for modeling and analyzing the floating raft vibration isolating equipment. The model of the floating raft and the floating raft vibration isolating system are theoretically analyzed and calculated, and the analysis results are in agreement with the test results. The transient response analysis of the system model follows the modal analysis of the floating raft vibration isolating system. And it is used to verify the shock-resistant performance. The analysis and calculation method used in this paper can be used to analyze the shock-resistant performance of onboard shock-resistant equipments.

  14. Hydrodynamic analysis of elastic floating collars in random waves

    Science.gov (United States)

    Bai, Xiao-dong; Zhao, Yun-peng; Dong, Guo-hai; Li, Yu-cheng

    2015-06-01

    As the main load-bearing component of fish cages, the floating collar supports the whole cage and undergoes large deformations. In this paper, a mathematical method is developed to study the motions and elastic deformations of elastic floating collars in random waves. The irregular wave is simulated by the random phase method and the statistical approach and Fourier transfer are applied to analyze the elastic response in both time and frequency domains. The governing equations of motions are established by Newton's second law, and the governing equations of deformations are obtained based on curved beam theory and modal superposition method. In order to validate the numerical model of the floating collar attacked by random waves, a series of physical model tests are conducted. Good relationship between numerical simulation and experimental observations is obtained. The numerical results indicate that the transfer function of out-of-plane and in-plane deformations increase with the increasing of wave frequency. In the frequency range between 0.6 Hz and 1.1 Hz, a linear relationship exists between the wave elevations and the deformations. The average phase difference between the wave elevation and out-of-plane deformation is 60° with waves leading and the phase between the wave elevation and in-plane deformation is 10° with waves lagging. In addition, the effect of fish net on the elastic response is analyzed. The results suggest that the deformation of the floating collar with fish net is a little larger than that without net.

  15. Hydrodynamic responses of a thin floating disk to regular waves

    CERN Document Server

    Yiew, Lucas; Meylan, Michael; French, Ben; Thomas, Giles

    2015-01-01

    Laboratory wave basin measurements of the surge, heave and pitch of a floating plastic disk caused by regular incident waves are presented. The measurements are used to validate two theoretical models: one based on slope-sliding theory and the other on combined potential-flow and thin-plate theories.

  16. The effect of floating houses on water quality

    NARCIS (Netherlands)

    Foka, E.; Rutten, M.; Boogaard, F.; Graaf, R. de; Lima, R.; Giesen, N. van de

    2015-01-01

    The need of an adaptive sustainable solution for the increased land scarcity, growing urbanization, climate change and flood risks resulted in the concept of the floating urbanization. In The Netherlands this new type of housing attracted the interest of local authorities, municipalities and water b

  17. A novel gastro-floating multiparticulate system for dipyridamole (DIP) based on a porous and low-density matrix core: in vitro and in vivo evaluation.

    Science.gov (United States)

    Li, Zhao; Xu, Heming; Li, Shujuan; Li, Qijun; Zhang, Wenji; Ye, Tiantian; Yang, Xinggang; Pan, Weisan

    2014-01-30

    The study was aimed to develop a novel gastro-floating multiparticulate system based on a porous and low-density matrix core with excellent floatability. The gastro-floating pellets (GFP) were composed of a porous matrix core, a drug loaded layer (DIP and HPMC), a sub-coating layer (HPMC) and a retarding layer (Eudragit(®) NE 30D). The porous matrix cores were evaluated in specific. EC was chosen as the matrix membrane for its rigidity and minimal expansion to large extent. The porous matrix core was achieved by the complete release of the bulk water soluble excipient from the EC coated beads, and mannitol was selected as the optimal water soluble excipient. SEM photomicrographs confirmed the structure of porous matrix cores. The compositions of GFP were investigated and optimized by orthogonal array design. The optimized formulation could sustain the drug release for 12h and float on the dissolution medium for at least 12h without lag time to float. The pharmacokinetic study was conducted in beagle dogs, and the relative bioavailability of the test preparation was 193.11±3.43%. In conclusion, the novel gastro-floating pellets can be developed as a promising approach for the gastro-retentive drug delivery systems. PMID:24368104

  18. Importance of Second-Order Difference-Frequency Wave-Diffraction Forces in the Validation of a Fast Semi-Submersible Floating Wind Turbine Model: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Couling, A. J.; Goupee, A. J.; Robertson, A. N.; Jonkman, J. M.

    2013-06-01

    To better access the abundant offshore wind resource, efforts across the world are being undertaken to develop and improve floating offshore wind turbine technologies. A critical aspect of creating reliable, mature floating wind turbine technology is the development, verification, and validation of efficient computer-aided-engineering (CAE) tools that can be relied upon in the design process. The National Renewable Energy Laboratory (NREL) has created a comprehensive, coupled analysis CAE tool for floating wind turbines, FAST, which has been verified and utilized in numerous floating wind turbine studies. Several efforts are currently underway that leverage the extensive 1/50th-scale DeepCwind wind/wave basin model test dataset, obtained at the Maritime Research Institute Netherlands (MARIN) in 2011, to validate the floating platform functionality of FAST to complement its already validated aerodynamic and structural simulation capabilities. In this paper, further work is undertaken to continue this validation. In particular, the ability of FAST to replicate global response behaviors associated with dynamic wind forces, second-order difference-frequency wave-diffraction forces and their interaction with one another are investigated.

  19. Uncovering Spatio-Temporal Cluster Patterns Using Massive Floating Car Data

    Directory of Open Access Journals (Sweden)

    Yifang Ban

    2013-05-01

    Full Text Available In this paper, we explore spatio-temporal clusters using massive floating car data from a complex network perspective. We analyzed over 85 million taxicab GPS points (floating car data collected in Wuhan, Hubei, China. Low-speed and stop points were selected to generate spatio-temporal clusters, which indicated the typical stop-and-go movement pattern in real-world traffic congestion. We found that the sizes of spatio-temporal clusters exhibited a power law distribution. This implies the presence of a scaling property; i.e., they can be naturally divided into a strong hierarchical structure: long time-duration ones (a low percentage whose values lie above the mean value and short ones (a high percentage whose values lie below. The spatio-temporal clusters at different levels represented the degree of traffic congestions, for example the higher the level, the worse the traffic congestions. Moreover, the distribution of traffic congestions varied spatio-temporally and demonstrated a multinuclear structure in urban road networks, which suggested there is a correlation to the corresponding internal mobile regularities of an urban system.

  20. Floating sandstones off El Hierro (Canary Islands, Spain: the peculiar case of the October 2011 eruption

    Directory of Open Access Journals (Sweden)

    V. R. Troll

    2011-12-01

    Full Text Available The eruption that started off the south coast of El Hierro, Canary Islands, in October 2011 has emitted intriguing eruption products found floating in the sea. These specimens appeared as floating volcanic "bombs" that have in the meantime been termed "restingolites" (after the close-by village of La Restinga and exhibit cores of white and porous pumice-like material. Currently the nature and origin of these "floating stones" is vigorously debated among researchers, with important implications for the interpretation of the hazard potential of the ongoing eruption. The "restingolites" have been proposed to be either (i juvenile high-silica magma (e.g. rhyolite, (ii remelted magmatic material (trachyte, (iii altered volcanic rock, or (iv reheated hyaloclastites or zeolite from the submarine slopes of El Hierro. Here, we provide evidence that supports yet a different conclusion. We have collected and analysed the structure and composition of samples and compared the results to previous work on similar rocks found in the archipelago. Based on their high silica content, the lack of igneous trace element signatures, and the presence of remnant quartz crystals, jasper fragments and carbonate relicts, we conclude that "restingolites" are in fact xenoliths from pre-island sedimentary rocks that were picked up and heated by the ascending magma causing them to partially melt and vesiculate. They hence represent messengers from depth that help us to understand the interaction between ascending magma and crustal lithologies in the Canary Islands as well as in similar Atlantic islands that rest on sediment/covered ocean crust (e.g. Cape Verdes, Azores. The occurrence of these "restingolites" does therefore not indicate the presence of an explosive high-silica magma that is involved in the ongoing eruption.

  1. Floating sandstones off El Hierro (Canary Islands, Spain): the peculiar case of the October 2011 eruption

    Science.gov (United States)

    Troll, V. R.; Klügel, A.; Longpré, M.-A.; Burchardt, S.; Deegan, F. M.; Carracedo, J. C.; Wiesmaier, S.; Kueppers, U.; Dahren, B.; Blythe, L. S.; Hansteen, T.; Freda, C.; Budd, D. A.; Jolis, E. M.; Jonsson, E.; Meade, F.; Berg, S.; Mancini, L.; Polacci, M.

    2011-12-01

    The eruption that started off the south coast of El Hierro, Canary Islands, in October 2011 has emitted intriguing eruption products found floating in the sea. These specimens appeared as floating volcanic "bombs" that have in the meantime been termed "restingolites" (after the close-by village of La Restinga) and exhibit cores of white and porous pumice-like material. Currently the nature and origin of these "floating stones" is vigorously debated among researchers, with important implications for the interpretation of the hazard potential of the ongoing eruption. The "restingolites" have been proposed to be either (i) juvenile high-silica magma (e.g. rhyolite), (ii) remelted magmatic material (trachyte), (iii) altered volcanic rock, or (iv) reheated hyaloclastites or zeolite from the submarine slopes of El Hierro. Here, we provide evidence that supports yet a different conclusion. We have collected and analysed the structure and composition of samples and compared the results to previous work on similar rocks found in the archipelago. Based on their high silica content, the lack of igneous trace element signatures, and the presence of remnant quartz crystals, jasper fragments and carbonate relicts, we conclude that "restingolites" are in fact xenoliths from pre-island sedimentary rocks that were picked up and heated by the ascending magma causing them to partially melt and vesiculate. They hence represent messengers from depth that help us to understand the interaction between ascending magma and crustal lithologies in the Canary Islands as well as in similar Atlantic islands that rest on sediment/covered ocean crust (e.g. Cape Verdes, Azores). The occurrence of these "restingolites" does therefore not indicate the presence of an explosive high-silica magma that is involved in the ongoing eruption.

  2. Comparison of Second-Order Loads on a Semisubmersible Floating Wind Turbine: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Gueydon, S.; Duarte, T.; Jonkman, J.; Bayati, I.; Sarmento, A.

    2014-03-01

    As offshore wind projects move to deeper waters, floating platforms become the most feasible solution for supporting the turbines. The oil and gas industry has gained experience with floating platforms that can be applied to offshore wind projects. This paper focuses on the analysis of second-order wave loading on semisubmersible platforms. Semisubmersibles, which are being chosen for different floating offshore wind concepts, are particularly prone to slow-drift motions. The slack catenary moorings usually result in large natural periods for surge and sway motions (more than 100 s), which are in the range of the second-order difference-frequency excitation force. Modeling these complex structures requires coupled design codes. Codes have been developed that include turbine aerodynamics, hydrodynamic forces on the platform, restoring forces from the mooring lines, flexibility of the turbine, and the influence of the turbine control system. In this paper two different codes are employed: FAST, which was developed by the National Renewable Energy Laboratory, and aNySIM, which was developed by the Maritime Research Institute Netherlands. The hydrodynamic loads are based on potential-flow theory, up to the second order. Hydrodynamic coefficients for wave excitation, radiation, and hydrostatic forces are obtained with two different panel codes, WAMIT (developed by the Massachusetts Institute of Technology) and DIFFRAC (developed by MARIN). The semisubmersible platform, developed for the International Energy Agency Wind Task 30 Offshore Code Comparison Collaboration Continuation project is used as a reference platform. Irregular waves are used to compare the behavior of this platform under slow-drift excitation loads. The results from this paper highlight the effects of these loads on semisubmersible-type platforms, which represent a promising solution for the commercial development of the offshore deepwater wind resource.

  3. Leasing of Nuclear Power Plants With Using Floating Technologies

    International Nuclear Information System (INIS)

    The proposal to organize and realize the international program on leasing of Nuclear Power Plant (NPP) reactor compartments is brought to the notice of potential partners. The proposal is oriented to the construction of new NPPs or to replacement of worked-out reactor units of the NPPs in operation on the sites situated near water area and to the use of afloat technologies for construction, mounting and transportation of reactor units as a Reactor Compartment Block Module (RCBM). According to the offered project the RCBM is fabricated in factory conditions at the largest Russian defense shipbuilding plant - State Unitary Enterprise 'Industrial Association SEVMASHPREDPRIYATIE' (SEVMASH) in the city of Severodvinsk of the Arkhangelsk region. After completion of assembling, testing and preliminary licensing the RCBM is given buoyancy by means of hermetic sealing and using pontoons and barges. The RCBM delivery to the NPP site situated near water area is performed by sea route. The RCBM is brought to the place of its installation with the use of appropriate hydraulic structures (canals, shipping locks), then is lowered on the basement constructed beforehand and incorporated into NPP scheme, of which the components are installed in advance. Floating means can be detached from the RCBM and used repeatedly for other RCBMs. Further procedure of NPP commissioning and its operation is carried out according to traditional method by power company in the framework of RCBM leasing with enlisting the services of firm-manufacturer's specialists either to provide reactor plant operation and concomitant processes or to perform author's supervision of operation. After completion of lifetime and reactor unloading the RCBM is dismantled with using the same afloat technology and taken away from NPP site to sea area entirely, together with its structures (reactor vessel, heat exchangers, pumps, pipelines and other equipment). Then RCBM is transported by shipping route to a firm

  4. High performance power VDMOSFETs with a split-gate floating np-well design

    International Nuclear Information System (INIS)

    Low gate charge power vertical double-diffused MOSFET devices are required for high-frequency systems. In this study, we proposed a split-gate with a floating np-well structure, which realizes a low gate charge performance without significantly degrading the breakdown voltage. The proposed structure removes the partial gate area between the gate and drain overlap area, and combines with an additional np-well. By this approach, the gate charge and switching loss can be reduced, and the breakdown voltage can be sustained. The gate–drain charge and gate charge of the split-gate with an np-well structure are 41.4% and 66.1% of the conventional device, respectively. These improvements are beneficial for reducing the switching loss of the devices. (rapid communication)

  5. 1T Pixel Using Floating-Body MOSFET for CMOS Image Sensors

    Directory of Open Access Journals (Sweden)

    Guo-Neng Lu

    2009-01-01

    Full Text Available We present a single-transistor pixel for CMOS image sensors (CIS. It is a floating-body MOSFET structure, which is used as photo-sensing device and source-follower transistor, and can be controlled to store and evacuate charges. Our investigation into this 1T pixel structure includes modeling to obtain analytical description of conversion gain. Model validation has been done by comparing theoretical predictions and experimental results. On the other hand, the 1T pixel structure has been implemented in different configurations, including rectangular-gate and ring-gate designs, and variations of oxidation parameters for the fabrication process. The pixel characteristics are presented and discussed.

  6. An integrated nuclear reactor unit for a floating low capacity nuclear power plant designed for power supply in remote areas with difficult access

    International Nuclear Information System (INIS)

    The paper describes the conceptual design of an integrated advanced safety nuclear reactor unit for a low capacity floating, NPP designed for power supply in areas which are remote with difficult access. The paper describes the major structural and lay-out components of the steam generator and reactor units with main technical characteristics. (author)

  7. Migration Laws of Floating Population in Mianyang%绵阳市流动人口迁移规律

    Institute of Scientific and Technical Information of China (English)

    刘鹏

    2005-01-01

    Based on the overall analysis of the floating population among big and medium-sized cities in China, thispaper, by means of statistics and questionnaires, makes a systematical study on the migratory features of the floating population in Mianyang, its employment structure, migrating causes and channels. According to the findings, the author finds a fact that with the strategy of Western Development, and with the construction of science and technology city of Mianyang, the migrating in Mianyang conforms to the general patterns of the migration, which has happened in those big and medium-sized cities in China. In addition, the city has a new but unique feature - economic factor, as the driving force of population migration, is quite distinct from that of those cities in eastern areas of China.

  8. ANALYTICAL MODELS OF FLOATING BRIDGES SUBJECTED BY MOVING LOADS FOR DIFFERENT WATER DEPTHS

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun; MIAO Guo-ping; LIU Jian-xun; SUN Wen-jun

    2008-01-01

    There are two types of floating bridge such as discrete-pontoon floating bridges and continuous-pontoon floating bridges.Analytical models of both floating bridges subjected by moving loads are presented to study the dynamic responses with hydrodynamic influence coefficients for different water depths. The beam theory and potential theory are introduced to produce themodels. The hydrodynamic coefficients and dynamic responses of bridges are evaluated by the boundary element method and by the Galerkin method of weighted residuals, respectively. Considering causal relationship between the frequencies of the oscillation of floating bridges and the added mass coefficients, an iteration method is introduced to compute hydrodynamic frequencies. The results indicate that water depth has little influence upon the dynamic responses of both types of floating bridges, so that the effect of water depth can be neglected during the course of designing floating bridges.

  9. Dynamic Analysis of A Pontoon-Separated Floating Bridge ubjected to A Moving Load

    Institute of Scientific and Technical Information of China (English)

    WANG Cong; FU Shi-xiao; LI Ning; CUI Wei-cheng; LIN Zhu-ming

    2006-01-01

    For the design and operation of a floating bridge, the understanding of its dynamic behavior under a moving load is of great importance. The purpose of this paper is to investigate the dynamic performances of a new type floating bridge, the pontoon-separated floating bridge, under the effect of a moving load. In the paper, a brief summary of the dynamic analysis of the floating bridge is first introduced. The motion equations for a pontoon-separated floating bridge, considering the nonlinear properties of connectors and vehicles' inertia effects, are proposed. The super-element method is applied to reduce the numerical analysis scale to solve the reduced equations. Based on the static analysis, the dynamic features of the new type floating bridge subjected to a moving load are investigated. It is found that the dynamic behavior of the pontoon-separated floating bridge is superior to that of the ribbon bridge by taking the nonlinearity of connectors into account.

  10. Designs and applications for floating-hydro power systems in small streams

    Energy Technology Data Exchange (ETDEWEB)

    Rehder, J.B.

    1983-01-01

    The project focuses on an appropriate technology for small-scale hydro power: floating waterwheels and turbines. For background, relic and existing systems such as early floating mills, traditional Amish waterwheels, and micro-hydro systems are examined. In the design phase of the project, new designs for Floating Hydro Power Systems include: an analysis of floatation materials and systems; a floating undershot waterwheel design; a floating cylinder (fiberglass storage tank) design; a submerged tube design; and a design for a floating platform with submerged propellers. Finally, in the applications phase, stream flow data from East Tennessee streams are used in a discussion of the potential applications of floating hydro power systems in small streams.

  11. A novel planar vertical double-diffused metal-oxide-semiconductor field-effect transistor with inhomogeneous floating islands

    Institute of Scientific and Technical Information of China (English)

    Ren Min; Li Ze-Hong; Liu Xiao-Long; Xie Jia-Xiong; Deng Guang-Min; Zhang Bo

    2011-01-01

    A novel planar vertical double-diffused metal-oxide-semiconductor (VDMOS) structure with an ultra-low specific on-resistance (Ron,sp),whose distinctive feature is the use of inhomogeneous floating p-islands in the n-drift region,is proposed.The theoretical limit of its Ron,sp is deduced,the influence of structure parameters on the breakdown voltage (BV) and Ron,sp are investigated,and the optimized results with BV of 83 V and Ron,sp of 54 mΩ.mm2 are obtained.Simulations show that the inhomogencous-floating-islands metal-oxide-semiconductor field-effect transistor (MOSFET)has a superior “Ron,sp/BV” trade-off to the conventional VDMOS (a 38% reduction of Ron,sp with the same BV) and the homogeneous-floating-islands MOSFET (a 10% reduction of Ron,sp with the same BV).The inhomogeneous-floatingislands MOSFET also has a much better body-diode characteristic than the superjunction MOSFET.Its reverse recovery peak current,reverse recovery time and reverse recovery charge are about 50,80 and 40% of those of the superjunction MOSFET,respectively.

  12. Wave-free floating body forms for a shallow sea area; Senkaiiki no naminashi futai keijo ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Kyozuka, Y.; Nariai, Y. [Kyushu University, Fukuoka (Japan)

    1997-10-01

    In column footing or semi-submergible type marine structures, a vertical wave force vanishes at a specific period of waves. This phenomenon is called wave-free characteristics. This wave-free characteristics make it possible to design marine structures superior in oscillation performance in waves. Since Bessho`s wave-free theory is useful only for an infinite water depth, this paper studied the wave-free theory for a shallow sea area. On a wave-free singularity and required floating body form, 2-D and 3-D axisymmetric floating body forms were determined, and vertical wave force characteristics of the obtained body forms were calculated and verified experimentally. Since the source term of the wave-free singularity was weaker in a shallow sea area than an infinite deep water area, resulting in the narrow width of the obtained wave-free body forms in a shallow sea area. The wave-free theory for a shallow sea area was verified by both numerical calculation based on a singularity distribution method and model experiment for these floating body forms. 3 refs., 10 figs.

  13. Wind and Wave Disturbances Compensation to Floating Offshore Wind Turbine Using Improved Individual Pitch Control Based on Fuzzy Control Strategy

    Directory of Open Access Journals (Sweden)

    Feng Yang

    2014-01-01

    Full Text Available Due to the rich and high quality of offshore wind resources, floating offshore wind turbine (FOWT arouses the attentions of many researchers. But on a floating platform, the wave and wind induced loads can significantly affect power regulation and vibration of the structure. Therefore, reducing these loads becomes a challenging part of the design of the floating system. To better alleviate these fatigue loads, a control system making compensations to these disturbances is proposed. In this paper an individual pitch control (IPC system integrated with disturbance accommodating control (DAC and model prediction control (MPC through fuzzy control is developed to alleviate the fatigue loads. DAC is mainly used to mitigate the effects of wind disturbance and MPC counteracts the effects of wave on the structure. The new individual pitch controller is tested on the NREL offshore 5 MW wind turbine mounted on a barge with a spread-mooring system, running in FAST, operating above-rated condition. Compared to the original baseline collective pitch control (CPC (Jonkman et al., 2007, the IPC system shows a better performance in reducing fatigue loads and is robust to complex wind and wave disturbances as well.

  14. Microbial mechanisms of using enhanced ecological floating beds for eutrophic water improvement.

    Science.gov (United States)

    Wu, Qing; Hu, Yue; Li, Shuqun; Peng, Sen; Zhao, Huabing

    2016-07-01

    Enhanced ecological floating beds were implemented to reduce nutrient quantity and improve the water quality of a eutrophic lake. The results showed that average removal efficiencies of CODCr, total nitrogen, NH3-N and total phosphorus for Canna indica L. set-up were 23.1%, 15.3%, 18.1% and 19.4% higher, respectively, than that of the setup with only substrate, and 14.2%, 12.8%, 7.9% and 11.9% higher than Iris pseudacorus L. ecological floating bed. The microbial community structure had obvious differences between devices and low similarity; bacteria were mainly attached on the fiber filling. The microbial population was abundant at the start and end of the experiment. Shannon index of samples selected ranged from 0.85 to 1.05. The sequencing results showed that fiber filling collected most uncultured bacteria species and the majority of bacteria on the plant roots were β-Proteobacteria and α-Proteobacteria. The co-dominant species attaching to the filling and plant was Nitrosomonadaceae. PMID:27035477

  15. Floating Offshore Wind in California: Gross Potential for Jobs and Economic Impacts from Two Future Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Speer, Bethany [National Renewable Energy Lab. (NREL), Golden, CO (United States); Keyser, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tegen, Suzanne [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-04-18

    Construction of the first offshore wind farm in the United States began in 2015, using fixed platform structures that are appropriate for shallow seafloors, like those located off of the East Coast and mid-Atlantic. However, floating platforms, which have yet to be deployed commercially, will likely need to anchor to the deeper seafloor if deployed off of the West Coast. To analyze the employment and economic potential for floating offshore wind along the West Coast, the Bureau of Ocean Energy Management (BOEM) has commissioned the National Renewable Energy Laboratory (NREL) to analyze two hypothetical, large-scale deployment scenarios for California: 16 GW of offshore wind by 2050 (Scenario A) and 10 GW of offshore wind by 2050 (Scenario B). The results of this analysis can be used to better understand the general scales of economic opportunities that could result from offshore wind development. Results show total state gross domestic product (GDP) impacts of $16.2 billion in Scenario B or $39.7 billion in Scenario A for construction; and $3.5 billion in Scenario B or $7.9 billion in Scenario A for the operations phases.

  16. Three-dimensional dynamic response modelling for floating nuclear power plants using finite element methods

    International Nuclear Information System (INIS)

    A modelling technique which can be used to obtain the dynamic response of a floating nuclear plant (FNP) moored in an artificial basin is presented. Hydrodynamic effects of the seawater in the basin have a significant impact on the response of the FNP and must be included. A three dimensional model of the platform and mooring system (using beam elements) is used, with the hydrodynamic effects represented by added mass and damping. For an essentially square plant in close proximity to the site structures, the three dimensional nature of the basin must be considered in evaluating the added mass and damping. A method for estimating these effects from planer finite element analyses is developed. The accuracy of the planar finite element model in obtaining two-dimensional added mass and damping is shown through comparison with existing the documented results. In addition, a comparison is shown for open ocean added mass and damping with a three-dimensional solution using velocity potential functions. It is concluded that the overall technique results in a reasonable and conservative calculation of the dynamic response of the floating nuclear plant. (orig./HP)

  17. A versatile floating production unit: the DP FPSO for Brazilian waters

    Energy Technology Data Exchange (ETDEWEB)

    Cann, Bram Van; Poldervaart, Leen [SBM Inc., Marly (Switzerland); Beenen, Marco [Gusto Engineering B.V. (Netherlands)

    2004-07-01

    Recent advances in drilling and completion techniques have resulted in improved well system design and completion reliability. Extended reach wells, multi-laterals, smart wells producing from multiple pay-zones and a range of completion methods provide high well production rates and significant recoverable reserves per well. During the initial phase of a field development, limited or no data may be available concerning the hydrocarbon reservoir. An extended well test facility or early production facility can provide additional high-quality production data related to properties of the recovered hydrocarbons, reservoir drive mechanism, reservoir pressure and temperature, etc. By obtaining critical reservoir and production data during the initial project phase, technical and commercial risks can be further quantified and a possible field development plan optimized. With exploration and production operations in deeper water, the cost for traditional (passive) station keeping systems of floating offshore structures has increased accordingly. Hardware and offshore installation costs associated with a passive mooring system of a floating offshore facilities can be significant, especially in case of operations in remote deep water areas and with frequent relocations. A DP system provides a cost-effective and proven means of station keeping and has been extensively applied to deep water drilling units. Operating as a first-stage field development unit, the DP-FPSO will enable a cost-effective means to gain valuable reservoir and production data, while generating early sales revenues. (author)

  18. Macro-Encapsulated PCM Cylinder Module Based on Paraffin and Float Stones

    Directory of Open Access Journals (Sweden)

    Kailiang Huang

    2016-05-01

    Full Text Available Organic phase change material (PCM with macro-encapsulation is attractive in energy storage applications as it has relatively low cost. This study focuses on using PET plastic pipes to encapsulate paraffin and using low-cost float stones to increase the thermal conductivity of PCM modules as they have a special structure of high porosity. Float stones were immersed in the liquid PCM and an ultrasonic welding method used to prevent leakage of the PET plastic pipes. Scanning electron microscopy (SEM was used to discover the appearance of the composite PCM. The thermal performance of the PCM cylinder module was analyzed through experimental tests of a constant-temperature water bath and numerical simulations. The result indicates that this PCM Ccylinder module is superior in thermal energy storage compared with the reference module even though fewer PCM was contained and the latent heat loss is considerable. The pipe diameter is an important parameter when using this kind of PCM cylinder module in water tanks.

  19. Studies of float glass surfaces by neutron and x-ray reflection

    CERN Document Server

    Dalgliesh, R

    2001-01-01

    applicability of current off-specular scattering models. A rich surface structure has been found which results in reflection effects that cannot be explained by these models. Model systems have also been developed in an attempt to combine x-ray fluorescence techniques with reflectivity. The surface of glass and glass coatings have been studied using x-ray and neutron scattering techniques. In particular, the effect of aqueous solutions and humid atmospheres on both the fire polished and the tin rich side of float glass have been investigated using neutron and x-ray reflection. Isotopic substitution has enabled the number density of water molecules within the float glass surface to be monitored with respect to immersion time, temperature and impurity content. A thin gel-like water-rich layer of thickness approx 30A is observed at the surface accompanied by a more deeply penetrating layer which increases in depth with time reaching approx 500A after 6 months. The rate of water ingression is higher than predicte...

  20. Influence of pitch motion on the turbulent mixing in the wake of floating wind turbine models

    Science.gov (United States)

    Rockel, Stanislav; Peinke, Joachim; Hoelling, Michael; Cal, Raúl Bayoán

    2014-11-01

    Offshore wind turbines use fixed foundations, which are economical in shallow water up to a depth of 50m. For deeper water areas floating support structures are feasible alternatives. The added degrees of freedom of a floating platform introduce additional oscillations to the wind turbine and therefore influence the aerodynamics at the rotor and its wake, respectively. The influence of platform pitch motion on the wake of an upstream wind turbine and a turbine positioned in the wake is investigated. Wind tunnel experiments were performed using classical bottom fixed wind turbine models and turbines in free pitch motion. Using 2D-3C particle image elocimetry (SPIV), wakes of both turbines were measured. In both cases - fixed and pitching - the inflow conditions were kept constant. The differences in the turbulent quantities of the wake of the upwind turbine for the fixed and oscillating case are investigated and their influence the wake of the downwind turbine. Our results show that platform pitch and oscillatory motions of the wind turbine have a strong impact on the shape of the fluctuating components of the wake. Also the turbulent mixing is changed by the oscillations, which is transferred to statistical quantities of higher order in the wake of the downwind turbine.

  1. Investigation of Response Amplitude Operators for Floating Offshore Wind Turbines: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Ramachandran, G. K. V.; Robertson, A.; Jonkman, J. M.; Masciola, M. D.

    2013-07-01

    This paper examines the consistency between response amplitude operators (RAOs) computed from WAMIT, a linear frequency-domain tool, to RAOs derived from time-domain computations based on white-noise wave excitation using FAST, a nonlinear aero-hydro-servo-elastic tool. The RAO comparison is first made for a rigid floating wind turbine without wind excitation. The investigation is further extended to examine how these RAOs change for a flexible and operational wind turbine. The RAOs are computed for below-rated, rated, and above-rated wind conditions. The method is applied to a floating wind system composed of the OC3-Hywind spar buoy and NREL 5-MW wind turbine. The responses are compared between FAST and WAMIT to verify the FAST model and to understand the influence of structural flexibility, aerodynamic damping, control actions, and waves on the system responses. The results show that based on the RAO computation procedure implemented, the WAMIT- and FAST-computed RAOs are similar (as expected) for a rigid turbine subjected to waves only. However, WAMIT is unable to model the excitation from a flexible turbine. Further, the presence of aerodynamic damping decreased the platform surge and pitch responses, as computed by both WAMIT and FAST when wind was included. Additionally, the influence of gyroscopic excitation increased the yaw response, which was captured by both WAMIT and FAST.

  2. Application of ethyl cellulose, microcrystalline cellulose and octadecanol for wax based floating solid dispersion pellets.

    Science.gov (United States)

    Yan, Hong-Xiang; Zhang, Shuang-Shuang; He, Jian-Hua; Liu, Jian-Ping

    2016-09-01

    The present study aimed to develop and optimize the wax based floating sustained-release dispersion pellets for a weakly acidic hydrophilic drug protocatechuic acid to achieve prolonged gastric residence time and improved bioavailability. This low-density drug delivery system consisted of octadecanol/microcrystalline cellulose mixture matrix pellet cores prepared by extrusion-spheronization technique, coated with drug/ethyl cellulose 100cp solid dispersion using single-step fluid-bed coating method. The formulation-optimized pellets could maintain excellent floating state without lag time and sustain the drug release efficiently for 12h based on non-Fickian transport mechanism. Observed by SEM, the optimized pellet was the dispersion-layered spherical structure containing a compact inner core. DSC, XRD and FTIR analysis revealed drug was uniformly dispersed in the amorphous molecule form and had no significant physicochemical interactions with the polymer dispersion carrier. The stability study of the resultant pellets further proved the rationality and integrity of the developed formulation. PMID:27185125

  3. Floating mucoadhesive alginate beads of amoxicillin trihydrate: A facile approach for H. pylori eradication.

    Science.gov (United States)

    Dey, Sanjoy Kumar; De, Pintu Kumar; De, Arnab; Ojha, Souvik; De, Ronita; Mukhopadhyay, Asish Kumar; Samanta, Amalesh

    2016-08-01

    This study investigates the design of sunflower oil entrapped floating and mucoadhesive beads of amoxicillin trihydrate using sodium alginate and hydroxypropyl methylcellulose as matrix polymers and chitosan as coating polymer to localize the antibiotic at the stomach site against Helicobacter pylori. Beads prepared by ionotropic gellation technique were evaluated for different physicochemical, in-vitro and in-vivo properties. Beads of all batches were floated for >24h with a maximum lag time of 46.3±3.2s. Scanning electron microscopy revealed that the beads were spherical in shape with few oil filled channels distributed throughout the surfaces and small pocket structures inside the matrix confirming oil entrapment. Prepared beads showed good mucoadhesiveness of 75.7±3.0% to 85.0±5.5%. The drug release profile was best fitted to Higuchi model with non fickian driven mechanism. The optimized batch showed 100% Helicobacter pylori growth inhibition in 15h in in-vitro culture. Furthermore, X-ray study in rabbit stomach confirmed the gastric retention of optimized formulation. The results exhibited that formulated beads may be preferred to localize the antibiotic in the gastric region to allow more availability of antibiotic at gastric mucus layer acting on Helicobacter pylori, thereby improving the therapeutic efficacy. PMID:27177460

  4. Floating-Point Arithmetic on Round-to-Nearest Representations

    CERN Document Server

    Kornerup, Peter; Panhaleux, Adrien

    2012-01-01

    Recently we introduced a class of number representations denoted RN-representations, allowing an un-biased rounding-to-nearest to take place by a simple truncation. In this paper we briefly review the binary fixed-point representation in an encoding which is essentially an ordinary 2's complement representation with an appended round-bit. Not only is this rounding a constant time operation, so is also sign inversion, both of which are at best log-time operations on ordinary 2's complement representations. Addition, multiplication and division is defined in such a way that rounding information can be carried along in a meaningful way, at minimal cost. Based on the fixed-point encoding we here define a floating point representation, and describe to some detail a possible implementation of a floating point arithmetic unit employing this representation, including also the directed roundings.

  5. Proton production, neutralisation and reduction in a floating water bridge

    Science.gov (United States)

    Sammer, Martina; Wexler, Adam D.; Kuntke, Philipp; Wiltsche, Helmar; Stanulewicz, Natalia; Lankmayr, Ernst; Woisetschläger, Jakob; Fuchs, Elmar C.

    2015-10-01

    This work reports on proton production, transport, reduction and neutralization in floating aqueous bridges under the application of a high dc voltage (‘floating water bridge’). Recently possible mechanisms for proton transfer through the bridge were suggested. In this work we visualize and describe the production of protons in the anolyte and their neutralization in the catholyte. Apart from that, protons are reduced to hydrogen due to electrolysis. Microbubbles are detached instantly, due to the electrohydrodynamic flow at the electrode surface. No larger, visible bubbles are formed and the system degasses through the bridge due to its higher local temperature. A detailed analysis of trace elements originating from beaker material, anode or the atmosphere is presented, showing that their influence on the overall conduction compared to the contribution of protons is negligible. Finally, an electrochemical rationale of high voltage electrolysis of low ionic strength solutions is presented.

  6. A floating water bridge produces water with excess charge

    International Nuclear Information System (INIS)

    Excess positive and negative Bjerrum-defect like charge (protonic and ‘aterprotonic’, from ancient Greek ατερ, ‘without’) in anolyte and catholyte of high voltage electrolysis of highly pure water was found during the so-called ‘floating water bridge’ experiment. The floating water bridge is a special case of an electrohydrodynamic liquid bridge and constitutes an intriguing phenomenon that occurs when a high potential difference (∼kV cm−1) is applied between two beakers of water. To obtain such results impedance spectroscopy was used. This measurement technique allows the depiction and simulation of complex aqueous systems as simple electric circuits. In the present work we show that there is an additional small contribution from the difference in conductivity between anolyte and catholyte which cannot be measured with a conductivity meter, but is clearly visible in an impedance spectrum. (paper)

  7. Controlled Phase Gate Based on an Electron Floating on Helium

    Institute of Scientific and Technical Information of China (English)

    SHI Yan-Li; MEI Feng; YU Ya-Fei; ZHANG Zhi-Ming

    2011-01-01

    We propose a scheme to generate the controlled phase gate by using an electron floating on liquid helium. The electron is also driven by a classical laser beam and by an oscillating magnetic field. In the process, the vibration of the electron is used as the qubus to couple the energy level qubit (1D Stark-shifted hydrogen) and spin qubit Ultimately. the controlled phase gate can be generated.%@@ We propose a scheme to generate the controlled phase gate by using an electron floating on liquid helium.The electron is also driven by a classical laser beam and by an oscillating magnetic field.In the process,the vibration of the electron is used as the qubus to couple the energy level qubit(1D Stark-shifted hydrogen) and spin qubit.Ultimately,the controlled phase gate can be generated.

  8. Road Network Change Detection Based on Floating Car Data

    Directory of Open Access Journals (Sweden)

    Luliang Tang

    2012-07-01

    Full Text Available The efficiency and accuracy of road network data in the latest electronic maps cannot satisfy the current demands of their application's needs. The present paper proposes a new method to use floating car data to detect and update changes in the road network. An experiment was carried out with actual data to test and verify the feasibility of the novel method. With the highly accurate map-matching between the floating car data and the current road network, the method not only determines road network changes promptly, but also uses incremental detection to obtain updated information on road networks in real time. Compared with the traditional updating method, the new method proposed in the current work can greatly shorten the update period of road networks and improve update efficiency.

  9. Online traffic state estimation based on floating car data

    CERN Document Server

    Kesting, Arne

    2010-01-01

    Besides the traditional data collection by stationary detectors, recent advances in wireless and sensor technologies have promoted new potentials for a vehicle-based data collection and local dissemination of information. By means of microscopic traffic simulations we study the problem of online estimation of the current traffic situation based on floating car data. Our focus is on the estimation on the up- and downstream jam fronts determining the extension of traffic congestion. We study the impact of delayed information transmission by short-range communication via wireless LAN in contrast to instantaneous information transmission to the roadside units by means of mobile radio. The delayed information transmission leads to systematic estimation errors which cannot be compensated for by a higher percentage of probe vehicles. Additional flow measurements from stationary detectors allow for a model-based prediction which is effective for much lower floating car percentages than 1%.

  10. Floating and flying ferrofluid bridges induced by external magnetic fields

    Science.gov (United States)

    Ma, Rongchao; Zhou, Yixin; Liu, Jing

    2015-04-01

    A ferrofluid is a mixture that exhibits both magnetism and fluidity. This merit enables the ferrofluid to be used in a wide variety of areas. Here we show that a floating ferrofluid bridge can be induced between two separated boards under a balanced external magnetic field generated by two magnets, while a flying ferrofluid bridge can be induced under an unbalanced external magnetic field generated by only one magnet. The mechanisms of the ferrofluid bridges were discussed and the corresponding mathematical equations were also established to describe the interacting magnetic force between the ferro particles inside the ferrofluid. This work answered a basic question that, except for the well-known floating water bridges that are related to electricity, one can also build up a liquid bridge that is related to magnetism.

  11. Quantitative Comparison of the Responses of Three Floating Platforms

    Energy Technology Data Exchange (ETDEWEB)

    Jonkman, J.; Matha, D.

    2010-03-01

    This report presents a comprehensive dynamic-response analysis of three offshore floating wind turbine concepts. Models were composed of one 5-MW turbine supported on land and three 5-MW turbines located offshore on a tension leg platform, a spar buoy, and a barge. A loads and stability analysis adhering to the procedures of international design standards was performed for each model using the fully coupled time-domain aero-hydro-servo-elastic design code FAST with AeroDyn and HydroDyn. The concepts are compared based on the calculated ultimate loads, fatigue loads, and instabilities. The results of this analysis will help resolve the fundamental design trade-offs between the floating-system concepts.

  12. ASIC Design of Floating-Point FFT Processor

    Institute of Scientific and Technical Information of China (English)

    陈禾; 赵忠武

    2004-01-01

    An application specific integrated circuit (ASIC) design of a 1024 points floating-point fast Fourier transform(FFT) processor is presented. It can satisfy the requirement of high accuracy FFT result in related fields. Several novel design techniques for floating-point adder and multiplier are introduced in detail to enhance the speed of the system. At the same time, the power consumption is decreased. The hardware area is effectively reduced as an improved butterfly processor is developed. There is a substantial increase in the performance of the design since a pipelined architecture is adopted, and very large scale integrated (VLSI) is easy to realize due to the regularity. A result of validation using field programmable gate array (FPGA) is shown at the end. When the system clock is set to 50 MHz, 204.8 μs is needed to complete the operation of FFT computation.

  13. Comparative Measurements of Indoor Radon in Homes and Floating Houses

    International Nuclear Information System (INIS)

    A survey of the radon (222Rn) concentrations in 318 homes and 152 floating houses (1410 samples) in Phitsanulok province, using a passive 222 Rn charcoal canister and measurement by gamma spectrometry. Floating houses showed significant lower mean levels (8.22 Bqm-3) than homes (21.56 Bqm-3) (p222Rn concentrations indicated that concrete homes had a higher level than wooden homes and homes lying on ground had a higher level than those built at 1 meter or more above ground. The estimated annual mean effective dose equivalent 0.35 mSvy-1 and the annual lung dose equivalent of 5.94 mSvy-1 were only one-third of the world mean estimates

  14. Ion irradiation damage on tin side surface of float glass

    International Nuclear Information System (INIS)

    Changes in the surface morphology and in-depth density variation in two surfaces of a float glass viz. the tin side and non-tin side surface, are investigated after 100 keV Ar ion irradiation. In the tin side surface, the irradiation caused a drastic change in density and surface roughness, whereas the other side (non-tin side surface) remained almost unaffected. Roughness of the tin side increases from 8 A to 41 A. Surface density also modified significantly with a redistribution of surface impurities. Monte Carlo simulations suggest that the displacement of tin and Fe impurities are responsible for the surface damage, which are experimentally examined by employing the total reflection X-ray fluorescence technique. Morphological and density changes are analyzed by grazing incidence X-ray reflectivity and atomic force microscopy techniques. Subsequent changes in surface morphology of float glass by ion irradiation are explained

  15. A floating water bridge produces water with excess charge

    Science.gov (United States)

    Fuchs, Elmar C.; Sammer, Martina; Wexler, Adam D.; Kuntke, Philipp; Woisetschläger, Jakob

    2016-03-01

    Excess positive and negative Bjerrum-defect like charge (protonic and ‘aterprotonic’, from ancient Greek ἄ'τɛρ, ‘without’) in anolyte and catholyte of high voltage electrolysis of highly pure water was found during the so-called ‘floating water bridge’ experiment. The floating water bridge is a special case of an electrohydrodynamic liquid bridge and constitutes an intriguing phenomenon that occurs when a high potential difference (~kV cm-1) is applied between two beakers of water. To obtain such results impedance spectroscopy was used. This measurement technique allows the depiction and simulation of complex aqueous systems as simple electric circuits. In the present work we show that there is an additional small contribution from the difference in conductivity between anolyte and catholyte which cannot be measured with a conductivity meter, but is clearly visible in an impedance spectrum.

  16. Research on Energy Conversion System of Floating Wave Energy Converter

    Institute of Scientific and Technical Information of China (English)

    张亚群; 盛松伟; 游亚戈; 吴必军; 刘洋

    2014-01-01

    A wave power device includes an energy harvesting system and a power take-off system. The power take-off system of a floating wave energy device is the key that converts wave energy into other forms. A set of hydraulic power take-off system, which suits for the floating wave energy devices, includes hydraulic system and power generation system. The hydraulic control system uses a special“self-hydraulic control system”to control hydraulic system to release or save energy under the maximum and the minimum pressures. The maximum pressure is enhanced to 23 MPa, the minimum to 9 MPa. Quite a few experiments show that the recent hydraulic system is evidently improved in efficiency and reliability than our previous one, that is expected to be great significant in the research and development of our prototype about wave energy conversion.

  17. Preparation and evaluation of floating tablets of pregabalin.

    Science.gov (United States)

    Kanwar, Navjot; Kumar, Rakesh; Sarwal, Amita; Sinha, V R

    2016-01-01

    Floating tablets of pregabalin were prepared using different concentrations of the gums (xanthan gum and guar gum), Carbopol 974P NF and HPMC K100. Optimized formulations were studied for physical tests, floating time, swelling behavior, in vitro release studies and stability studies. In vitro drug release was higher for tablet batches containing guar and xanthan gum as compared to the batches containing Carbopol 974P NF. Tablet batches were subjected to stability studies and evaluated by different parameters (drug release, drug content, FTIR and DSC studies). The optimized tablet batch was selected for in vivo pharmacodynamic studies (PTZ induced seizures). The results obtained showed that the onset of jerks and clonus were delayed and extensor phase was abolished with time in treated groups. A significant difference (p > 0.05) was observed in control and treated group behavior indicating an excellent activity of the formulation for a longer period (>12 h). PMID:26146770

  18. Dynamic Analysis of a Floating Vertical Axis Wind Turbine Under Emergency Shutdown Using Hydrodynamic Brake

    DEFF Research Database (Denmark)

    Wang, K.; Hansen, Martin Otto Laver; Moan, T.

    2014-01-01

    Emergency shutdown is always a challenge for an operating vertical axis wind turbine. A 5-MW vertical axis wind turbine with a Darrieus rotor mounted on a semi-submersible support structure was examined in this study. Coupled non-linear aero-hydro-servo-elastic simulations of the floating vertical...... axis wind turbine were carried out for emergency shutdown cases over a range of environmental conditions based on correlated wind and wave data. When generator failure happens, a brake should be applied to stop the acceleration of the rotor to prevent the rotor from overspeeding and subsequent disaster....... In addition to the traditional mechanical brake, a novel hydrodynamic brake was presented to apply to the shutdown case. The effects of the hydrodynamic brake on the platform motions and structural loads under normal operating conditions and during the emergency shutdown events were evaluated. The...

  19. A new generation of power MOSFET based on the concept of "Floating Islands"

    Science.gov (United States)

    Cézac, N.; Morancho, F.; Rossel, P.; Tranduc, H.; Peyre-Lavigne, A.

    2000-06-01

    In this paper, a new concept called "Floating Islands diode" (FLI-diode) is proposed: the voltage handling capability of this new diode is assumed by the association of several PN junctions in series. This concept can be applied to any power devices (lateral or vertical). An example of vertical power MOSFET based on this concept is presented here: this new structure, called "FLIMOSFET", exhibits improved on-state resistance performance when compared to the conventional VDMOSFET. For instance, for a breakdown voltage of 900 volts, the theoretical performance are strongly improved in term of specific on-resistance (reduction of about 70% relative to the conventional structure and 40% relative to the silicon limit). Moreover the specific on-resistance theoretical limits of FLIMOSFET family are determined and compared to those of the "Superjunction" MOS Transistor family: this comparison shows the strong interest of the FLIMOSFET in the 200 volts-1000 volts breakdown voltage range.

  20. Al-O complex formation in ion implanted Czochralski and floating-zone Si substrates

    Science.gov (United States)

    La Ferla, A.; Torrisi, L.; Galvagno, G.; Rimini, E.; Ciavola, G.; Carnera, A.; Gasparotto, A.

    1993-01-01

    Aluminum ions at 100 MeV were implanted into floating-zone (FZ) and Czochralski (CZ) grown Si substrates. At this energy the influence of the surface on the subsequent thermal treatment is negligible. In FZ samples the electrical active dose, as measured by spreading resistance profilometry, is independent of the annealing time at 1200 °C. In the CZ samples instead it considerably decreases with time. Secondary ion mass spectrometry analysis in CZ samples have revealed the presence of a multipeak structure around the projected range region for both Al and O signals. In FZ the structure is just detectable. The results imply that the Al-O complex formation is enhanced by the presence of oxygen but that it is catalyzed by the damage created during the implant. The carrier profiles coincide in both CZ and FZ diffused substrates by predeposition of Al from a solid source, i.e., in damage-free samples.

  1. FORMULATION AND EVALUATION OF GASTRO RETENTIVE FLOATING TABLETS OF GLICLAZIDE

    OpenAIRE

    Thakkar Hardik Kumar Rajeshbhai; A. Senthil; Chavda Gajendrasinh A; Patel Jyotindra N; Narayanswamy V.B.

    2011-01-01

    A gastro retentive floating drug delivery system containing gliclazide was prepared in the form of tablet and evaluated for its processing parameters and in vitro release behaviour. Gliclazide is a selective second-generation sulphonyl urea used in treatment of hyperglycemia and it absorbs rapidly and completely. However its absorption is erratic in diabetic patient due to its impaired gastric motility or gastric emptying. To overcome these drawbacks, the present investigation was to develop ...

  2. ROLE OF NATURAL POLYMERS USED IN FLOATING DRUG DELIVERY SYSTEM

    OpenAIRE

    Singh Amit Kumar; Dubey Vivek; Arora Vandana

    2012-01-01

    Floating drug delivery system is the form of gastro-retentive drug delivery system that controls the kinetic release rate of a drug to a specific site for its pharmacological action. These are achieved by use of various polymeric substance including natural polymers such as Guar Gum, Xanthan Gum, Gellan Gum etc. This delivery system prolongs the retention time of the drug in the stomach as compared to conventional dosage forms. The present article highlights the use of polymers for the formul...

  3. FORMULATION AND EVALUTION OF GASTRO RETENTIVE FLOATING TABLETS OF GLIPIZIDE

    OpenAIRE

    Raja Benhar Dickson; Thakkar Hardik Rajeshbhai; Paramasivam Sureshkumar; Jamsheer Assain KK; Adimoolam Senthil

    2011-01-01

    A gastro retentive floating drug delivery system containing glipizide was prepared in the form of tablet and evaluated for its processing parameters and in vitro release behaviour. Glipizide is a selective second-generation sulphonyl urea used in treatment of hyperglycemia and it absorbs rapidly and completely. However its absorption is erratic in diabetic patient due to its impaired gastric motility or gastric emptying. To overcome these drawbacks, the present investigation was to develop a ...

  4. Study the Effect of Urban Ecosystem to Floating Population

    Science.gov (United States)

    Tu, Wubin; Zhang, Lingxian; Zhang, Xiaoshuan; Fu, Zetian

    The urban ecosystem is a complex system hat are compounded of environment -economic-social ,the factors of urban ecosystem affect the decision of the floating population to chose city .In this paper ,we according to the urban ecosystem to design the questionnaire ,and study the weights of the factors that influence the decision by AHP ,and find that economy is most important which is 0.6806, the society and ecological environment are 0.2014and0.1180.

  5. EDKDSP: Reprogrammable Floating Point Accelerators on KINTEX FPGA with HDMI

    Czech Academy of Sciences Publication Activity Database

    Kadlec, Jiří

    Grenoble, 2013. [DATE 2013 Design, Automation and Test in Europe. 2013.03.18-2013.03.22, Grenoble] R&D Projects: GA MŠk(CZ) 7H12004 Keywords : FPGA * programmable accelerators * computer video processing Subject RIV: JC - Computer Hardware ; Software http://library.utia.cas.cz/separaty/2013/ZS/kadlec-edkdsp reprogrammable floating point accelerators on kintex fpga with hdmi.pdf

  6. Classifying Floating Potential Measurement Unit Data Products as Science Data

    Science.gov (United States)

    Coffey, Victoria; Minow, Joseph

    2015-01-01

    We are Co-Investigators for the Floating Potential Measurement Unit (FPMU) on the International Space Station (ISS) and members of the FPMU operations and data analysis team. We are providing this memo for the purpose of classifying raw and processed FPMU data products and ancillary data as NASA science data with unrestricted, public availability in order to best support science uses of the data.

  7. Organic Transplant Production of Some Winter Vegetable Crops in Float

    OpenAIRE

    KURTAR, E. S.

    2013-01-01

    The aim of this study was to investigate the feasibility of using cattle manure and pigeon manure on seedling production of some winter vegetables as leaf cabbage, white cabbage, red cabbage and cauliflower in organic system compared to conventional system in float. Shoot length (cm), root length (cm), leaf number, root/shoot rate, shoot fresh weight (g), shoot dry weight (g), shoot dry matter rate (%), root fresh weight (g), root dry weight (g) and root dry matter rate (%) were investigated ...

  8. Floating Exchange Rates in Peru, 1950-54

    OpenAIRE

    Lyons, Richard K.

    1991-01-01

    I test three potentially complementary models in an effort to capture the fundamentals that underlaid the market's determination of Peru's floating exchange rate through the period 1950-54: the first is an expectational purchasing power parity (PPP) model which maintains that asset market forces were driving the exchange rate to its perceived PPP level; the second is a flexible-price monetary model; and the third is a model along the lines described by Tsiang (1957) which emphasizes world pri...

  9. FLOATING MULTI-PARTICULATE ORAL DRUG DELIVERY SYSTEM: A REVIEW

    OpenAIRE

    Jaimini Manish; Joshi Vishalkumar

    2012-01-01

    The purpose of this review on floating drug delivery systems is the recent literature with mechanism to achieve gastric retention by floatation. Gastroretentive drug delivery system have advantages besides providing better bioavailability to poorly absorbed drugs and a required release profile thus attracting interest of pharmaceutical formulation. These systems are useful to several problems encountered during the development of a pharmaceutical dosage form. The objectives of the review disc...

  10. A REVIEW ON FLOATING TYPE GASTRORETENTIVE DRUG DELIVERY SYSTEM

    OpenAIRE

    Pallavi Pal; Vijay Sharma; Lalit Singh

    2012-01-01

    Oral controlled release delivery systems are programmed to deliver the drug in predictable time frame that will increase the efficacy and minimize the adverse effects and increase the bioavailability of drugs. Oral route is considered mostnatural, uncomplicated, convenient and safe due to its ease of administration, patient acceptance, and cost-effective manufacturing process.Floating Drug delivery system are designed to prolong the gastric residence time after oral administration, at particu...

  11. Design Optimization and Performance Evaluation of a Floating Breakwater

    OpenAIRE

    Mahmuddin, Faisal

    2012-01-01

    In order to design an optimal floating breakwater with a high performance in a wide range of frequencies, its characteristics and performance in 2D and 3D cases are analyzed. For obtaining an optimal 2D model shape, an optimization method called Genetic Algorithm (GA) combined with Boundary Element Method (BEM) is employed. The accuracy of BEM analysis is confirmed using numerical relations such as Haskind-Newman and energy conservation relations. Moreover, since the investigated model will b...

  12. Realistic Design of a Floating Breakwater Design with Moonpools

    OpenAIRE

    Faisal Mahmuddin

    2014-01-01

    In an attempt to obtain a 2D floating breakwater model with high performance in wave reflection, genetic algorithm (GA) was combined with boundary element method (BEM) in the previous study. The performance of the obtained model was verified with numerical relations as well as an experiment in towing tank. Moreover, its performance and characteristics in 3D case were also evaluated in the subsequent study. However, because the 3D model is formed by simply extruding the 2D shape in...

  13. Floating anterior lens capsule: an unusual case of true exfoliation

    OpenAIRE

    Riffle, John

    2010-01-01

    A rare case of delamination and replication of the anterior lens capsule into prominent floating folds in the anterior chamber approximately 55 years after a penetrating injury to the eye and anterior lens capsule is reported. Classically, true exfoliation of the anterior lens capsule has been reported in individuals who have been exposed to intense heat over a prolonged period. However, more recently cases of true exfoliation of the anterior lens capsule have been reported in patients who ha...

  14. Formulation and Evaluation of Floating tablets of Ondansetron Hydrochloride

    OpenAIRE

    S.Daisy chella kumari; S.Vengatesh, K. Elango; R. Devi Damayanthi; N. Deattu, P.Christina

    2015-01-01

    The purpose of the present study was to develop an optimized gastric floating drug delivery system (GFDDS) containing Ondansetron Hydrochloride as a model drug by using various proportions of polymers such as HPMC K4M and Ethyl cellulose. This was employed to enhance the bioavailability and therapeutic efficacy of the drug. The sustained release formulations of Ondansetron Hydrochloride using hydrophobic and hydrophilic polymers were prepared by wet granulation method. Optimization of formula...

  15. Correct Handling of Floating-Point Computations in Symbolic Execution

    OpenAIRE

    Botella, Bernard; Gotlieb, Arnaud; Michel, Claude

    2004-01-01

    Symbolic execution is a program testing technique which evaluates statements with symbolic input data along a selected path of the control flow graph. The process involves the computation of path conditions that tend to be simplified or solved in order either to get test data that sensitize the selected path or to demonstrate infeasibility of the path. In the presence of floating-point computations, the current strategy consists in using a constraint solver based on rationals or reals. Unfort...

  16. Cascade analysis of a floating wind turbine rotor

    OpenAIRE

    Eliassen, Lene; Jakobsen, Jasna B.; Knauer, Andreas; Nielsen, Finn Gunnar

    2014-01-01

    Mounting a wind turbine on a floating foundation introduces more complexity to the aerodynamic loading. The floater motion contains a wide range of frequencies. To study some of the basic dynamic load effect on the blades due to these motions, a two-dimensional cascade approach, combined with a potential vortex method, is used. This is an alternative method to study the aeroelastic behavior of wind turbines that is different from the traditional blade element momentum m...

  17. Collective pitch feedforward control of floating wind turbines using lidar

    OpenAIRE

    Schlipf, David; Simley, Eric; Lemmer, Frank; Pao, Lucy; Cheng, Po Wen

    2015-01-01

    In this work a collective pitch feedforward controller for floating wind turbines is presented. The feedforward controller provides a pitch rate update to a conventional feedback controller based on a wind speed preview. The controller is designed similar to the one for onshore turbines, which has proven its capability to improve wind turbine control performance in field tests. In a first design step, perfect wind preview and a calm sea is assumed. Under these assumptions the feedforward cont...

  18. Nonlinear model predictive control of floating wind turbines

    OpenAIRE

    Schlipf, David; Sandner, Frank; Raach, Steffen; Matha, Denis; Cheng, Po Wen

    2013-01-01

    In this work a nonlinear model predictive control method for a floating wind turbine is presented. A reduced nonlinear model including disturbance preview of wind and waves is derived and implemented to compute optimal input trajectories for collective pitch and the generator torque. A cost functional is introduced which fulfills all desired constraints and controller goals for above rated wind conditions. The controller is tested for extreme and fatigue load cases and a significant reduction...

  19. Integrated Mechanical and Hydrodynamic Modeling of Offshore Floating Wind Turbines

    OpenAIRE

    Pedersen, Morten Dinhoff

    2009-01-01

    This thesis presents the development of a nonlinear mechanical and hydrodynamical model for floating offshore wind turbines. The model employs results from robotics to model the equations of motion. A simple rigid-body turbine model has been implemented. Hydrodynamic forces are modeled in part with the generalized Morison equation, in part with direct integration of the Froude-Krylov pressures. Buoyancy forces are modeled via a non-linear buoyancy scheme that considers variations in water-pla...

  20. Improved tank test procedures for scaled floating offshore wind turbines

    OpenAIRE

    Müller, Kolja; Sandner, Frank; Bredmose, Henrik; Azcona, José; Manjock, Andreas; Pereira, Ricardo

    2014-01-01

    This study collects issues from previous tank test campaigns of scaled Floating Offshore Wind Turbines (FOWT), compares the different scaling methodologies, points out critical aspects and shows possible alternatives and recommendations for future tests depending on the specific objective. Furthermore, it gives practical recommendations for the modeling and construction of scaled rotors. The presented scaling procedure will be applied in tank tests within the EU Seventh Framework Program InnW...

  1. Mooring Line Damping Estimation for a Floating Wind Turbine

    OpenAIRE

    Dongsheng Qiao; Jinping Ou

    2014-01-01

    The dynamic responses of mooring line serve important functions in the station keeping of a floating wind turbine (FWT). Mooring line damping significantly influences the global motions of a FWT. This study investigates the estimation of mooring line damping on the basis of the National Renewable Energy Laboratory 5 MW offshore wind turbine model that is mounted on the ITI Energy barge. A numerical estimation method is derived from the energy absorption of a mooring line resulting from FWT mo...

  2. Simulation as a decisison support tool in maintenance float systems

    OpenAIRE

    Pereira, Guilherme; Peito, Francisco; Leitão, Armando; Dias, Luís M. S.

    2011-01-01

    This paper is concerned with the use of simulation as a decision support tool in maintenance systems, specifically in MPS (Maintenance Float Systems). For this purpose and due to its high complexity, in this paper the authors explore and present a possible way to construct a MPS model using Arena® simulation language, where some of the most common performance measures are identified, calculated and analysed.

  3. Simulation as a decision support tool in maintenance float systems

    OpenAIRE

    Peito, Francisco; Pereira, Guilherme; Leitão, Armando; Dias, Luís M. S.

    2011-01-01

    This paper is concerned with the use of simulation as a decision support tool in maintenance systems, specifically in MFS (Maintenance Float Systems). For this purpose and due to its high complexity, in this paper the authors explore and present a possible way to construct a MFS model using Arena® simulation language, where some of the most common performance measures are identified, calculated and analysed.

  4. A Low-Voltage Floating-Gate MOS Biquad

    OpenAIRE

    Rodríguez-Villegas, Esther O.; Alberto Yúfera; Adoración Rueda

    2001-01-01

    A second-order gm-C filter based on the Floating-Gate MOS (FGMOS) technique is presented. It uses a new fully differential transconductor and works at 2 V of voltage supply with a full differential input linear range and a THD below 1%. Programming and tuning are performed by means of a single voltage signal. The transconductor incorporates a novel Common-Mode Feedback Circuit (CMFB) based also on FGMOS transistors.

  5. Design and Optimization of Floating Drug Delivery System of Acyclovir

    OpenAIRE

    Kharia A; Hiremath S; Singhai A; Omray L; Jain S

    2010-01-01

    The purpose of the present work was to design and optimize floating drug delivery systems of acyclovir using psyllium husk and hydroxypropylmethylcellulose K4M as the polymers and sodium bicarbonate as a gas generating agent. The tablets were prepared by wet granulation method. A 32 full factorial design was used for optimization of drug release profile. The amount of psyllium husk (X1) and hydroxypropylmethylcellulose K4M (X2) were selected as independent variables. The times required for 50...

  6. Floating bioadhesive drug delivery system using novel effervescent agents

    OpenAIRE

    Belgamwar V; Surana S

    2009-01-01

    Oral sustained release gastroretentive dosage forms offer many advantages for drugs having absorption from the upper gastrointestinal tract and improve the bioavailability of medications that are characterized by the narrow absorption window. A new gastroretentive sustained release delivery system using the novel effervescent system was developed with floating, swellable, and bioadhesive properties. Various release retarding polymers like psyllium husk, HPMC K15M, and a swelling agent crosspo...

  7. Formulation and Evaluation of effervescent floating matrix tablets of Ofloxacin

    OpenAIRE

    Mohammed Asif Hussain; Mahender B; Maimuna Anjum

    2014-01-01

    The aim of present study was to develop Effervescent floating matrix tablets of Ofloxacin by wet granulation method using gas generating agents like Sodium bicarbonate, Citric acid and polymers like HPMC K100M, HPMC K4M, Psyllium husk and Xanthan gum. The prepared tablets evaluated in terms of their pre-compression parameters, physical characteristics, buoyancy lag time and dissolution studies. Optimization of formulation was done by studying effect of polymer on drug release. FT-IR studies i...

  8. Bending strength analysis of steel-composite submerged floating tunnels

    OpenAIRE

    Han, T H; Won, D.; Han, S. H.; Park, W. S.; Yum, K.D.

    2013-01-01

    A submerged floating tunnel (SFT) must have enough strength to resist to various external loadings such as bending, torsion, tension, and compression. The expected main deformation of SFT is caused by bending moment. And this bending moment makes tensile stress and compression stress on the wall of SFT. Thus, bending moment is a main affecting factor on the safety of SFT. Until now, a reinforced concrete tunnel was suggested for SFT by other researchers. In this study, an internal...

  9. Fixed or Floating Exchange Regimes; Does it Matter for Inflation?

    OpenAIRE

    Peter J. Quirk

    1994-01-01

    This paper reviews recent experience with the choice of floating or fixed (“anchor”) exchange regimes in industrial and developing countries. It concludes that desirable differences between the two sets of regimes have narrowed, owing to the useful operational role of exchange rate margins and unavoidable medium-term rate adjustments in the context of fixed regimes. A survey of recent empirical cross-country literature also suggests little unambiguous association of the choice of exchange reg...

  10. Design and optimization of floating drug delivery system of acyclovir

    Directory of Open Access Journals (Sweden)

    Kharia A

    2010-01-01

    Full Text Available The purpose of the present work was to design and optimize floating drug delivery systems of acyclovir using psyllium husk and hydroxypropylmethylcellulose K4M as the polymers and sodium bicarbonate as a gas generating agent. The tablets were prepared by wet granulation method. A 32 full factorial design was used for optimization of drug release profile. The amount of psyllium husk (X1 and hydroxypropylmethylcellulose K4M (X2 were selected as independent variables. The times required for 50% (t 50% and 70% (t 70% drug dissolution were selected as dependent variables. All the designed nine batches of formulations were evaluated for hardness, friability, weight variation, drug content uniformity, swelling index, in vitro buoyancy, and in vitro drug release profile. All formulations had floating lag time below 3 min and constantly floated on dissolution medium for more than 24 h. Validity of the developed polynomial equation was verified by designing two check point formulations (C1 and C2. The closeness of predicted and observed values for t 50% and t 70% indicates validity of derived equations for the dependent variables. These studies indicated that the proper balance between psyllium husk and hydroxypropylmethylcellulose K4M can produce a drug dissolution profile similar to the predicted dissolution profile. The optimized formulations followed Higuchi′s kinetics while the drug release mechanism was found to be anomalous type, controlled by diffusion through the swollen matrix.

  11. DEVELOPMENT AND EVALUATION OF FLOATING-MUCOADHESIVE DIPYRIDAMOLE TABLET

    Directory of Open Access Journals (Sweden)

    BIRAJDAR SHIVPRASAD M. DARVESHWAR JAGDEEP D

    2013-09-01

    Full Text Available The present study was aimed towards development and evaluation of tablet as a floating-Mucoadhesive drug delivery system, which can provide sustained release of the model drug. The work also was aimed to study various parameters affecting the behavior of floating-mucoadhesive tablet in oral dosage form. Formulation of Gastro-Retentive Dosage Forms (GRDFs containing suitable drug candidate which would remain in stomach and/or upper part of GIT for prolonged period of time thereby is maximizing the drug release at desired site within the time before GRDFs leave the stomach and or upper part of GIT. Dipyridamole is BCS class II drug having low solubility and high permeability. It is soluble at low pH but insoluble in high pH (i.e. alkaline ph of small intestine its oral bioavailability is 37-66% & biological half life is also short (40 min. In this study the bioavailability of the dipyridamole increase by using various concentration of HPMC, Carbapol and Sodium bicarbonate for swelling, mucoadhesive and floating behavior respectively. Bioadhesive strength depends upon carbapol as concentration of polymer increases bioadhesive strength also increases. HPMC is water Swealable but Carbapol is hydrogel in nature it restricts movement of polymer and affect the swelling index.

  12. Formulation and Evaluation of Floating tablets of Ondansetron Hydrochloride

    Directory of Open Access Journals (Sweden)

    S.Daisy chella kumari

    2015-12-01

    Full Text Available The purpose of the present study was to develop an optimized gastric floating drug delivery system (GFDDS containing Ondansetron Hydrochloride as a model drug by using various proportions of polymers such as HPMC K4M and Ethyl cellulose. This was employed to enhance the bioavailability and therapeutic efficacy of the drug. The sustained release formulations of Ondansetron Hydrochloride using hydrophobic and hydrophilic polymers were prepared by wet granulation method. Optimization of formulation was done by studying effect of drug to polymer ratio on drug release. FT-IR studies indicated absence of any interaction between Ondansetron Hydrochloride, polymer (HPMC K4M, Ethyl cellulose and excipients. Six formulations were prepared and formulation F6 possessed good floating property with total floating time between 8-12 hours. The tablets were also evaluated for its hardness, friability, and in-vitro evaluation test. All parameters complied with IP limits. Results of this study indicated that the combinations of hydrophilic polymers with hydrophobic polymers are suitable to optimize sustained release formulation of Ondansetron Hydrochloride.

  13. Rapid prediction of floating and sinking components of raw coal

    Institute of Scientific and Technical Information of China (English)

    Wang Guanghui; Kuang Yali; Wang Zhangguo; Ji Li; Wang Ying

    2012-01-01

    A model that rapidly predicts the density components of raw coal is described.It is based on a three-grade fast float/sink test.The recent comprehensive monthly floating and sinking data are used for comparison.The predicted data are used to draw washability curves and to provide a rapid evaluation of the effect from heavy medium induced separation.Thirty-one production shifts worth of fast float/sink data and the corresponding quick ash data are used to verify the model.The results show a small error with an arithmetic average of 0.53 and an absolute average error of 1.50.This indicates that this model has high precision.The theoretical yield from the washability curves is 76.47% for the monthly comprehensive data and 81.31% using the model data.This is for a desired cleaned coal ash of 9%.The relative error between these two is 6.33%,which is small and indicates that the predicted data can be used to rapidly evaluate the separation effect of gravity separation equipment.

  14. ACECLOFENAC FLOATING TABLETS - A PROMISING SUSTAINED RELEASE DOSAGE FORM

    Directory of Open Access Journals (Sweden)

    Ambati Brahma reddy

    2011-06-01

    Full Text Available The purpose of the present study was to develop an optimized gastric floating drug delivery system (GFDDS containing Aceclofenac as a model drug by using various proportion of polymers such as HPMC E5M and Eudragit RS 100. This was employed to enhance the bioavailability and therapeutic efficacy of the drug. The sustained release formulations of aceclofenac using hydrophobic and hydrophilic polymers were prepared by direct compression method. Optimization of formulation was done by studying effect of drug to polymer ratio on drug release. FT- IR studies indicated absence of any interaction between aceclofenac, polymer (Eudragit RS 100, HPMCE5M and excipients. Five formulations were prepared and formulation A5 possessed good floating property with total floating time between 8-10 hours. The tablets were also evaluated for its hardness, friability and other In- vitro evaluation tests. All parameters complied with IP limits. Results of this study indicated that the combinations of hydrophilic polymers with hydrophobic polymers are suitable to optimize sustained release formulation of aceclofenac.

  15. Characterization of floating element balance for field panel testing

    Science.gov (United States)

    Hunsucker, J. Travis; Gardner, Harrison; Swain, Geoffrey

    2015-11-01

    Multiple experiments were performed to investigate and characterize the uncertainty and bias of a through-hull flush mounted floating element balance designed to measure the hydrodynamic drag forces of biofouling and marine coatings on 25 x 30 cm test panels. The instrument is located in a wet well on the aft portion of a 27' Chris Craft Commander. Testing occurs over a series of speeds ranging from a Froude number of 0.50-2.20 on calm days (force 3 or less) in waters along the central east coast of Florida. Recent modifications have been made to the instrumentation in an effort to improve the overall accuracy of the system. This study compares frictional drag measurements of the floating element balance to those obtained using the Clauser chart and Preston tube methods for a smooth surface. Boundary layer velocity profiles are examined to understand the nature of the flow over the testing section. Roughness function values for 60 and 220 grit sandpaper were calculated from data obtained using the floating element balance. These values were compared with previous work to examine the overall bias of the methodology. Repeat measurements for a smooth panel were analyzed to characterize the overall uncertainty in the system. This research was supported by the Office of Naval Research under grants N00014-10-1-0919 and N00014-11-1-0915.

  16. Prospect of floating desalination facilities using nuclear energy in Indonesia

    International Nuclear Information System (INIS)

    This paper summarizes studies on the water demand and supply problems in Indonesia in the last few years. During the dry season in 1990, it was reported that lack of fresh drinking water in Java and Bali amounted to 2.4 x 106 ton/month. Since Indonesia consists of more than 13,000 islands, more problems are faced by other islands. The studies are focused on certain regions (groups of islands) which may have a potential for using a floating desalination facility. Water reservoirs in each island and delivery systems from the floating desalination facilities need to be assessed to see the prospective uses of the systems. Cheap, self-forgiving and easily operated systems, using transportable ship mounted desalination facilities, may be required as a solution to the water supply shortages for these islands. Conclusions based on current problems in water demand and supply and comments on the prospective future market using floating desalination facilities in Indonesia are also given. (author). 9 refs, 10 tabs

  17. Characterising dynamic non-linearity in floating wind turbines

    International Nuclear Information System (INIS)

    Fully coupled aero-hydro-control-elastic codes are being developed to cope with the new modelling challenges presented by floating wind turbines, but there is also a place for more efficient methods of analysis. One option is linearisation and analysis in the frequency domain. For this to be an effective method, the non-linearities in the system must be well understood. The present study focusses on understanding the dynamic response of the rotor to the overall platform motion, as would arise from wave loading, by using a simple model of a floating wind turbine with a rigid tower and flexible rotor (represented by hinged rigid blades). First, an equation of motion of the blade is derived and an approximate solution for the blade response is found using the perturbation method. Secondly, the full non-linear solution is found by time- domain simulation. The response is found to be linear at lower platform pitching frequencies, becoming non-linear at higher frequencies, with the approximate solution giving good results for weakly non-linear behaviour. Higher rotor speeds have a stabilising effect on the response. In the context of typical floating turbine parameters, it is concluded that the blade flapwise response is likely to be linear

  18. Characterising dynamic non-linearity in floating wind turbines

    Science.gov (United States)

    Lupton, R. C.

    2014-12-01

    Fully coupled aero-hydro-control-elastic codes are being developed to cope with the new modelling challenges presented by floating wind turbines, but there is also a place for more efficient methods of analysis. One option is linearisation and analysis in the frequency domain. For this to be an effective method, the non-linearities in the system must be well understood. The present study focusses on understanding the dynamic response of the rotor to the overall platform motion, as would arise from wave loading, by using a simple model of a floating wind turbine with a rigid tower and flexible rotor (represented by hinged rigid blades). First, an equation of motion of the blade is derived and an approximate solution for the blade response is found using the perturbation method. Secondly, the full non-linear solution is found by time- domain simulation. The response is found to be linear at lower platform pitching frequencies, becoming non-linear at higher frequencies, with the approximate solution giving good results for weakly non-linear behaviour. Higher rotor speeds have a stabilising effect on the response. In the context of typical floating turbine parameters, it is concluded that the blade flapwise response is likely to be linear.

  19. Performance of floating oil booms in unsheltered waters

    Science.gov (United States)

    Iglesias, Gregorio; Castro, Alberte

    2013-04-01

    Oil booms are a fundamental tool to diminish the impact of an oil spill. They tend to perform reasonably well in sheltered waters, e.g. within a harbour. However, their performance is often inadequate in open water conditions, under waves, winds and currents. And it is precisely in those conditions that they are needed if oil slicks are to be prevented from reaching certain particularly sensitive areas, such as estuaries, rias, etc. (Castro et al., 2010; Iglesias et al., 2010). In this work the performance of floating oil booms under waves and currents is assessed on the basis of laboratory experiments carried out in a state-of-the-art wave-current flume. Different oil boom models are used, representative of booms with long and short skirts and with different weights. The results show that different booms behave very differently under waves and currents, hence the importance of selecting the boom design that is appropriate for the actual conditions under which it will have to contain the oil slick. Thus, different oil booms should be used for different areas. References A. Castro, G. Iglesias, R. Carballo, J.A. Fraguela, 2010. Floating boom performance under waves and currents, Journal of Hazardous Materials 174, 226-235 G. Iglesias, A.Castro, J.A.Fraguela, 2010. Artificial intelligence applied to floating boom behavior under waves and currents, Ocean Engineering 37, 1513-1521.

  20. Modelling hydrological management for the restoration of acidified floating fens

    Science.gov (United States)

    Dekker, Stefan C.; Barendregt, Aat; Bootsma, Margien C.; Schot, Paul P.

    2005-12-01

    Wetlands show a large decline in biodiversity. To protect and restore this biodiversity, many restoration projects are carried out. Hydrology in wetlands controls the chemical and biological processes and may be the most important factor regulating wetland function and development. Hydrological models may be used to simulate these processes and to evaluate management scenarios for restoration. HYDRUS2D, a combined saturated-unsaturated groundwater flow and transport model, is presented. This simulates near-surface hydrological processes in an acidified floating fen, with the aim to evaluate the effect of hydrological restoration in terms of conditions for biodiversity. In the acidified floating fen in the nature reserve Ilperveld (The Netherlands), a trench system was dug for the purpose of creating a runoff channel for acid rainwater in wet periods and to enable circum-neutral surface water to enter the fen in dry periods. The model is calibrated against measured conductivity values for a 5 year period. From the model simulations, it was found that lateral flow in the floating raft is limited. Furthermore, the model shows that the best management option is a combination of trenches and inundation, which gave the best soil water quality in the root zone. It is concluded that hydrological models can be used for the calculation of management scenarios in restoration projects. The combined saturated-unsaturated model concept used in this paper is able to incorporate the governing hydrological processes in the wetland root zones. Copyright