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. [Ag67(SPhMe2)32(PPh3)8]3+: Synthesis, Total Structure, and Optical Properties of a Large Box-Shaped Silver Nanocluster

    KAUST Repository

    Alhilaly, Mohammad J.

    2016-10-13

    Engineering the surface ligands of metal nanoparticles is critical in designing unique arrangements of metal atoms. Here, we report the synthesis and total structure determination of a large box-shaped Ag-67 nanocluster (NC) protected by a mixed shell of thiolate (2,4-dimethylbenzenethiolate, SPhMe2) and phosphine (triphenylphosphine, PPh3) ligands. Single crystal X-ray diffraction (SCXRD) and electrospray ionization mass spectrometry (ESI-MS) revealed the cluster formula to be [Ag-67(SPhMe2)(32)(PPh3)(8)](3+). The crystal structure shows an Ag-23 metal core covered by a layer of Ag44S32P8 arranged in the shape of a box. The Ag-13, core was formed through an unprecedented centered cuboctahedron, i.e., Ag-13, unlike the common centered Ag-13 icosahedron geometry. Two types of ligand motifs, eight AgS3P and eight bridging thiols, were found to stabilize the whole cluster. The optical spectrum of this NC displayed highly structured multiple absorption peaks. The electronic structure and optical spectrum of Ag-67 were computed using time-dependent density functional theory (TDDFT) for both the full cluster [Ag-67(SPhMe2)(32)(PPh3)(8)](3+) and a reduced model [Ag-67(SH)(32)(PH3)(8)](3+). The lowest metal-to-metal transitions in the range 500-800 nm could be explained by considering the reduced model that shows almost identical electronic states to 32 free electrons in a jellium box. The successful synthesis of the large box-shaped Ag-67 NC facilitated by the combined use of phosphine and thiol paves the way for synthesizing other metal clusters with unprecedented shapes by judicious choice of thiols and phosphines.

  3. 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.

  4. 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.

  5. 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.

  6. On the dynamics of floating structures

    CERN Document Server

    Lannes, David

    2016-01-01

    This paper addresses the floating body problem which consists in studying the interaction of surface water waves with a floating body. We propose a new formulation of the water waves problem that can easily be generalized in order to take into account the presence of a floating body. The resulting equations have a compressible-incompressible structure in which the interior pressure exerted by the fluid on the floating body is a Lagrange multiplier that can be determined through the resolution of a $d$-dimensional elliptic equation, where $d$ is the horizontal dimension. In the case where the object is freely floating, we decompose the hydrodynamic force and torque exerted by the fluid on the solid in order to exhibit an added mass effect; in the one dimensional case $d=1$, the computations can be carried out explicitly. We also show that this approach in which the interior pressure appears as a Lagrange multiplier can be implemented on reduced asymptotic models such as the nonlinear shallow water equations an...

  7. 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.

  8. 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.

  9. Production process for hyperbolical box-shape structures of Zhuhai opera house%珠海歌剧院双曲立面箱形构件制作工艺

    Institute of Scientific and Technical Information of China (English)

    张伟; 叶翔; 杜冰冰; 阙志雄; 项玲玲

    2013-01-01

    The steel members at radial direction for Zhuhai Opera House main structure is arc-shaped members and crankled members at circular direction. The requirements on production quality,dimensional precision,etc. are quite high. The paper puts forward the production critics and difficulties for producing the crankled members and arc -shaped members and concluded the production technique for crankled members according to the non-molding technique used for producing the crankled members and the production experiences gathered during production process. In this paper, the technologies that are adopted for the same or similar engineering has certain reference and reference value, especially the welding procedure has great practical significance.%珠海歌剧院主体结构中径向杆件为弧形构件,环向杆件为弯扭构件.弧形构件和弯扭构件的加工制作质量、尺寸精度等要求高,珠海歌剧院工程弯扭构件制作采用先进的无模成型技术,根据构件的制作总结制作技术经验,提出了弯扭构件及弧形构件加工制作难点和关键技术要点,并总结了弯扭构件的制作技术.所采用的技术对相同或相似的工程有一定的借鉴和参考价值,特别是焊接程序有较大的现实意义.

  10. 现浇地下工程多孔箱形结构模板支架选型与应用%Selection and Application of the Cast-in-situ Porous Box-shaped Structure Supports for Underground Works

    Institute of Scientific and Technical Information of China (English)

    李文昌; 徐洪华

    2015-01-01

    澳大隧道主体结构工程具有工期紧、箱孔多、断面尺寸大且渐变等特点,针对这些特点,项目部在模板支架选型上也采取了多元化。根据常用的多种地下工程箱形结构模板支架(满堂支架支撑木模、轻型单侧支架配承插型盘扣式钢管支架支撑模板、台车模板)在本工程中的实践应用进行了归纳比较,并总结了各模板支架的优缺点及其经济性、可操作性和工效性等。%The main structural works of the university of Macau seabed tunnel project had taken a diversified approach in selection of the box⁃shaped supports which had a tight schedule, too much box holes, large size and gradient sections etc. This paper compared the practical applications of the variety of the common box⁃shaped supports for the underground work in this project, including full scaffold, light single support combined with socket plate type steel pipe scaffold and trolley formwork, and meanwhile summarized advantages and disadvantages of the various box⁃shaped supports, economy, efficiency and operability.

  11. Analysis of Responses of Floating Dual Pontoon Structure

    Institute of Scientific and Technical Information of China (English)

    WENG Wen-Kai; CHOU Chung-Ren

    2007-01-01

    A numerical model is developed by use of the boundary integral equation method to investigate the responses of a two-dimensional floating structure.The structure under consideration consisting of two pontoons,is connected by a rigid framework,and linked to the sea floor by a mooring system.The theoretical conception is based on potential theory with linear external forces,and applied to an arbitrarily shaped body and water depth.The discussion includes the influence of draft and space between pontoons on the responses of the floating structure.Finally,the validity of the method is adequately verified by experimental results.

  12. 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...

  13. SEMICONDUCTOR DEVICES: Trench gate IGBT structure with floating P region

    Science.gov (United States)

    Mengliang, Qian; Zehong, Li; Bo, Zhang; Zhaoji, Li

    2010-02-01

    A new trench gate IGBT structure with a floating P region is proposed, which introduces a floating P region into the trench accumulation layer controlled IGBT (TAC-IGBT). The new structure maintains a low on-state voltage drop and large forward biased safe operating area (FBSOA) of the TAC-IGBT structure while reduces the leakage current and improves the breakdown voltage. In addition, it enlarges the short circuit safe operating area (SCSOA) of the TAC-IGBT, and is simple in fabrication and design. Simulation results indicate that, for IGBT structures with a breakdown voltage of 1200 V, the leakage current of the new trench gate IGBT structure is one order of magnitude lower than the TAC-IGBT structure and the breakdown voltage is 150 V higher than the TAC-IGBT.

  14. Children's Knowledge of Hierarchical Phrase Structure: Quantifier Floating in Japanese

    Science.gov (United States)

    Suzuki, Takaaki; Yoshinaga, Naoko

    2013-01-01

    The interpretation of floating quantifiers in Japanese requires knowledge of hierarchical phrase structure. However, the input to children is insufficient or even misleading, as our analysis indicates. This presents an intriguing question on learnability: do children interpret floating quantifiers based on a structure-dependent rule which is not…

  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. 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.

  17. A LINEAR HYBRID MODEL OF MSE AND BEM FOR FLOATING STRUCTURES IN COASTAL ZONES

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun; MIAO Guo-ping

    2006-01-01

    A linear hybrid model of Mild Slope Equation (MSE) and Boundary Element Method (BEM) is developed to study the wave propagation around floating structures in coastal zones. Both the wave refraction under the influence of topography and the wave diffraction by floating structures are considered. Hence, the model provides wave properties around the coastal floating structures of arbitrary shape but also the wave forces on and the hydrodynamic characteristics of the structures. Different approaches are compared to demonstrate the validity of the present hybrid model. Several numerical tests are carried out for the cases of pontoons under different circumstances. The results show that the influence of topography on the hydrodynamic characteristics of floating structures in coastal regions is important and must not be ignored in the most wave period range with practical interests.

  18. Hydroelastic Analysis of Very Large Floating Structures Using Plate Green Functions

    Institute of Scientific and Technical Information of China (English)

    闫红梅; 崔维成; 刘应中

    2003-01-01

    Great attention has been paid to the development of very large floating structures. Owing to their extreme large size and great flexibility, the coupling between the structural deformation and fluid motion is significant. This is a typical problem of hydroelasticity. Efficient and accurate estimation of the hydroelastic response of very large floating structures in waves is very important for design. In this paper, the plate Green function and fluid Green function are combined to analyze the hydroelastic response of very large floating structures. The plate Green function here is a new one proposed by the authors and it satisfies all boundary conditions for free-free rectangular plates on elastic foundations. The results are compared with some experimental data. It is shown that the method proposed in this paper is efficient and accurate. Finally, various factors affecting the hydroelastic response of very large floating structures are also studied.

  19. 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.

  20. 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...

  1. 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.

  2. Wind Turbine Controller to Mitigate Structural Loads on a Floating Wind Turbine Platform

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Paul A.; Peiffer, Antoine; Schlipf, David

    2016-06-24

    This paper summarizes the control design work that was performed to optimize the controller of a wind turbine on the WindFloat structure. The WindFloat is a semi-submersible floating platform designed to be a support structure for a multi-megawatt power-generating wind turbine. A controller developed for a bottom-fixed wind turbine configuration was modified for use when the turbine is mounted on the WindFloat platform. This results in an efficient platform heel resonance mitigation scheme. In addition several control modules, designed with a coupled linear model, were added to the fixed-bottom baseline controller. The approach was tested in a fully coupled nonlinear aero-hydroelastic simulation tool in which wind and wave disturbances were modeled. This testing yielded significant improvements in platform global performance and tower-base-bending loading.

  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. STM observation of a box-shaped graphene nanostructure appeared after mechanical cleavage of pyrolytic graphite

    CERN Document Server

    Lapshin, Rostislav V

    2016-01-01

    A description is given of a three-dimensional box-shaped graphene (BSG) nanostructure formed/uncovered by mechanical cleavage of highly oriented pyrolytic graphite (HOPG). The discovered nanostructure is a multilayer system of parallel hollow channels located along the surface and having quadrangular cross-section. The thickness of the channel walls/facets is approximately equal to 1 nm. The typical width of channel facets makes about 25 nm, the channel length is 390 nm and more. The investigation of the found nanostructure by means of a scanning tunneling microscope (STM) allows us to draw a conclusion that it is possible to make spatial constructions of graphene similar to the discovered one by mechanical compression, bending, splitting, and shifting graphite surface layers. The distinctive features of such constructions are the following: simplicity of the preparation method, small contact area between graphene planes and a substrate, large surface area, nanometer cross-sectional sizes of the channels, lar...

  6. Numerical simulation study on active and passive hydroforming process optimization of box shaped part

    Science.gov (United States)

    Zeng, Y. P.; Dong, J. L.; He, T. D.; Wang, B.

    2016-08-01

    Low qualified rate and inferior quality frequently occurring in the general deep drawing process of a certain box-shaped part, now use hydroforming to optimize forming process, in order to study the effect of hydroforming for improving the quality and formability, purposed five process schemes: general deep drawing, active hydroforming, passive hydroforming, general deep drawing combined with active hydroforming, passive combined with active hydroforming. Each process was simulated by finite element simulation and results were analysed. The results indicate the passive combined with active hydroforming is the best scheme which can obtain smallest thickness thinning and satisfactory formability, then optimized hydroforming pressure, blank holder force subsequently by adjust the simulation parameters. Research result proves that active/passive hydroforming is a new method for complex parts forming.

  7. A horizontal parallax table-top floating image system with freeform optical film structure

    Science.gov (United States)

    Chou, Ping-Yen; Huang, Yi-Pai; Liao, Chien-Chung; Chang, Chuan-Chung; Chuang, Fu-Ming Fleming; Tsai, Chao-Hsu

    2016-06-01

    In this paper, a new structure of horizontal parallax light field 3D floating image display system was proposed. The structure consists of pico-projectors, Fresnel lens, micro-lens array and sub-lens array with freeform shape. By the functions of optical components, each light field of projectors could be controlled as a fan ray, which has high directivity in horizontal and wide scattered angle in vertical. Furthermore, according to the reverse light tracing and integral image display technique, horizontal parallax floating 3D could be demonstrated in the system. Simulated results show that the proposed 3D display structure has a good image quality and the crosstalk is also limited below 22.9%. Compared with other 3D technologies, this structure could have more benefits, including displaying real high resolution floating image, unnecessary of physical hardware on the image plane, scalability of large size system, without the noise from spinning component, and so on.

  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...... support structure and mooring system for the DeepWind concept. The conceptual design is formulated as an optimization problem: Starting with an initial configuration, the optimization procedure tries to find a cheaper solution while satisfying a set of design requirements. This approach utilizes available...

  9. On the modelling of the dynamics of elastically deformable floating structures

    DEFF Research Database (Denmark)

    Seng, Sopheak; Malenica, Sime; Jensen, Jørgen Juncher;

    2015-01-01

    In this paper we are reexamining the dynamic equations of an elastically deformable floating structure to identify and evaluate the contribution from the inertia cross coupling terms which commonly have been neglected due to the assumption of small structural deformation. Numerical experiments...

  10. An Analytical Solution of Partially Penetrating Hydraulic Fractures in a Box-Shaped Reservoir

    Directory of Open Access Journals (Sweden)

    He Zhang

    2015-01-01

    Full Text Available This paper presents a new method to give an analytical solution in Laplace domain directly that is used to describe pressure transient behavior of partially penetrating hydraulic fractures in a box-shaped reservoir with closed boundaries. The basic building block of the method is to solve diffusivity equation with the integration of Dirac function over the distance that is presented for the first time. Different from the traditional method of using the source solution and Green’s function presented by Gringarten and Ramey, this paper uses Laplace transform and Fourier transform to solve the diffusivity equation and the analytical solution obtained is accurate and simple. The effects of parameters including fracture height, fracture length, the position of the fracture, and reservoir width on the pressure and pressure derivative are fully investigated. The advantage of the analytical solution is easy to incorporate storage coefficient and skin factor. It can also reduce the amount of computation and compute efficiently and quickly.

  11. Second Order Nonlinear Hydroelastic Analyses of Floating Bodies - the Primary Consideration of Nonlinear Structure

    DEFF Research Database (Denmark)

    Chen, X.; Cui, W.; Jensen, Jørgen Juncher

    2003-01-01

    The theory and typical numerical results of a second order nonlinear hydroelastic analysis of floating bodies are presented in a series of papers in which only nonlinearity in fluids is considered. Under the assumption of linear fluid, the hydroelastic analysis methods of nonlinear structure are ...

  12. 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

  13. Hydrodynamic Excitation Forces on Floating Structures with Finite Displacements

    DEFF Research Database (Denmark)

    Andersen, Morten Thøtt; Nielsen, Søren R. K.

    2015-01-01

    excitation force is solely a function of time, hence the body is fixed in reference to the wave field. In this paper, the instantaneous position of the body is included in the calculation of the excitation force. Even though the displacement of the structure relative to a characteristic wavelength......This paper aims to present an extended version of the classic linear wave excitation force theory. Linear wave theory implies that the wave load is applied in the referential state of the structure. In reality, the load is acting in the dynamically altered state. In the classic notation the wave...

  14. Structural and morphological study of damage in lead/acid batteries during cycling and floating tests

    Science.gov (United States)

    Brissaud, C.; Reumont, G.; Smaha, J. P.; Foct, J.

    Premature capacity loss is a severe problem observed in lead/acid batteries; it has been localised at the grid/positive active material interface (PAM) and in the PAM. In order to understand these phenomena, cycled batteries with Pb-Sb-Sn and Pb-Ca-Sn positive grid alloys were studied and compared with floated batteries with Pb-Ca-Sn positive grid alloys. The evolution of the crystallographic and morphological structure of the PAM and of the grid/PAM interface during the tests were investigated. Formation of isolated agglomerates of PAM by the phenomena assimilated to sintering was found to be the reason of the failure of cycled batteries, whereas the intergranular corrosion of the grid initiated the floated batteries' end of life. The results and mechanisms of these phenomena are presented.

  15. Applicability of WaveWatch-III wave model to fatigue assessment of offshore floating structures

    Science.gov (United States)

    Zou, Tao; Kaminski, Miroslaw Lech

    2016-09-01

    In design and operation of floating offshore structures, one has to avoid fatigue failures caused by action of ocean waves. The aim of this paper is to investigate the applicability of WaveWatch-III wave model to fatigue assessment of offshore floating structures. The applicability was investigated for Bluewaters' FPSO (Floating Production, Storage and Offloading) which had been turret moored at Sable field for half a decade. The waves were predicted as sea-state time series consisting of one wind sea and one swell. The predicted waves were compared with wave data obtained from ERA-interim and buoy measurements. Furthermore, the fatigue calculations were also carried out for main deck and side shell locations. It has been concluded that predicted fatigue damages of main deck using WaveWatch-III are in a very good agreement regardless of differences in predicted wind waves and swells caused by differences in wave system partitioning. When compared to buoy measurements, the model underestimates fatigue damages of side shell by approximately 30 %. The reason for that has been found in wider directional spreading of actual waves. The WaveWatch-III wave model has been found suitable for the fatigue assessment. However, more attention should be paid on relative wave directionality, wave system partitioning and uncertainty analysis in further development.

  16. Survey of Experience Using Reinforced Concrete in Floating Marine Structures.

    Science.gov (United States)

    1983-01-01

    Great Britain," Transactions Institution of Naval Architects, Vol. 60, pp 154, 1918. 3.76 . . . . .. . . . . . . ... , 3.22 Haviland, Jean , "American...BOWEN, G.L., "CORRISION IN FERROCEMENT," J. FERRO- CEMENT, VOL. 5, NO. 4, PP 13-27, 1976. 40. BAZANT , Z.P., "PHYSICAL "ODEL FOR STEEL CORROSION IN...CONCRETE SEA STRUCTURES - APPLICATION," ASCE J., STRUCT. DIV., VOL. 105, NO. 6, PP 1155-1166, JUNE 1979, (4 REF). 41. BAZANT , Z.P., "PHYSICAL MODEL FOR

  17. 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.

  18. A Study on Hydroelastic Response of Box-Type Very Large Floating Structures

    Institute of Scientific and Technical Information of China (English)

    王志军; 李润培; 舒志

    2001-01-01

    The application of very large floating structure (VLFS) to the utilization of ocean space and exploitation of ocean resources has become one of the issues of great interest in international ocean engineering field. Owing to the advantage of simplicity in structure and low cost of construction and maintenance, box-type VLFS can be used in the calm water area near the coast as the structure configuration of floating airport. In this paper, a 3D linear hydroelastic theory is used to study the dynamic response of box-type VLFS in sinusoidal regular waves. A beam model and a 3D FEM model are respectively employed to describe the dynamic characteristics of the box-type structure in vacuum. A hydrodynamic model (3D potential theory of flexible body) is applied to investigate the effect of different dry models on the hydroelastic response of box-type structure. Based on the calculation of hydroelastic response in regular waves, the rigid body motion displacement, flexible deflection, and the short term and long term wave induced bending moments are also predicted.

  19. 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.

  20. 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.

  1. Numerical study of roll motion of a 2-D floating structure in viscous flow

    Institute of Scientific and Technical Information of China (English)

    Lifen CHEN; Liang SUN; Jun ZANG; A J HILLIS; A R PLUMMER

    2016-01-01

    In the present study, an open source CFD tool, OpenFOAM has been extended and applied to investigate roll motion of a 2-D rectangular barge induced by nonlinear regular waves in viscous flow. Comparisons of the present OpenFOAM results with published potential-flow solutions and experimental data have indicated that the newly extended OpenFOAM model is very capable of accurate modelling of wave interaction with freely rolling structures. The wave-induced roll motions, hydrodynamic forces on the barge, velocities and vorticity fields in the vicinity of the structure in the presence of waves have been investigated to reveal the real physics involved in the wave induced roll motion of a 2-D floating structure. Parametric analysis has been carried out to examine the effect of structure dimension and body draft on the roll motion.

  2. Time-domain simulation for water wave radiation by floating structures (Part A)

    Institute of Scientific and Technical Information of China (English)

    XU Gang; DUAN Wen-yang

    2008-01-01

    Direct time-domain simulation of floating structures has advantages: it can calculate wave pressure fields and forces directly;and it is useful for coupled analysis of floating structures with a mooring system. A time-domain boundary integral equation method is presented to simulate three-dimensional water wave radiation problems. A stable form of the integration free-surface boundary condition (IFBC) is used to update velocity potentials on the free surface. A multi-transmitting formula (MTF) method with an artificial speed is introduced to the artificial radiation boundary (ARB). The method was applied to simulate a semi-spherical liquefied natural gas (LNG) carrier and a semi-submersible undergoing specified harmonic motion. Numerical parameters such as the form of the ARB,and the time and space discretization related to this method are discussed. It was found that a good agreement can be obtained when artificial speed is between 0.6 and 1.6 times the phase velocity of water waves in the MTF method. A simulation can be done for a long period of time by this method without problems of instability,and the method is also accurate and computationally efficient.

  3. Space structure capturing and assembling by experimental free-floating robot satellite (EFFORTS) simulators

    Science.gov (United States)

    Yoshida, K.

    1993-09-01

    In order to study and validate practical availability of control schemes for in-orbit operational free-floating robots, a research group at the Tokyo Institute of Technology has developed the Experimental Free-FlOating RoboT Satellite (EFFORTS-I and II) simulators, which enable to examine 2-dimensional pseudo-micro gravity motion dynamics by air lift system. The robot model comprising a satellite base body and articulated manipulator arms with grippers and wrist force sensors, makes horizontal motion without mechanical disturbances or external forces. This paper presents the control methods and experimental results for spacecraft/manipulator control paying attention to the reaction dynamics, and assembly and deployment operation of space structures. The paper focuses the discussion of (1) hardware design of EFFORTS simulators, (2) dynamic modeling and a basic control concept for space free-floating manipulators, (3) satellite attitude control coordinating with manipulator dynamics, (4) practical force control for dexterous manipulation, and (5) experimental results on above topics.

  4. Wave interaction with Very Large Floating Structure (VLFS using BEM approach – Revisited

    Directory of Open Access Journals (Sweden)

    Anoop I. Shirkol

    2016-09-01

    Full Text Available In the present study, a brief discussion on the hydroelastic analysis of VLFS using Boundary Element Method (BEM with basic assumptions, boundary conditions and support conditions required are presented. An overview of present scenario about development of VLFS using BEM and also future prospects are presented. The study on existing VLFS systems floated in the sea around world could be considered as indicative of the present state of affairs. Further, various numerical methods adopted by the researchers is reviewed in particular, on the hydroelastic analysis of VLFS, dynamic, static and structural response of the system is discussed. The study presented herein will be helpful to naval architects, ocean and structural engineers for suitable design and analysis of VLFS subjected to wave force.

  5. 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.

  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 driven...... 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 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....

  8. Radiation effects on floating rings of voltage terminating structure in Si p-on-n detectors

    Energy Technology Data Exchange (ETDEWEB)

    Eremin, V. [Ioffe Physical-Technical Institute of Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Egorov, N. [Research Institute of Material Science and Technology, 124460 Zelenograd, Moscow (Russian Federation); Eremin, I. [Ioffe Physical-Technical Institute of Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Fadeeva, N. [Ioffe Physical-Technical Institute of Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Saint Petersburg Electrotechnical University “LETI”, 197376 St. Petersburg (Russian Federation); Verbitskaya, E., E-mail: elena.verbitskaya@cern.ch [Ioffe Physical-Technical Institute of Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation)

    2013-12-01

    In the 1990s a suggestion was put forward that the space charge limited current mechanism is responsible for stabilization of the I–V characteristics in irradiated Si p-on-n detectors. This mechanism is switched on in the case of high concentration of radiation induced deep traps which via holes accumulation will reduce the electric field in the regions of breakdown. The present study shows that voltage terminating structure (VTS) consisting of the floating p{sup +} rings as a main element for stabilization of I–V characteristics in nonirradiated detectors is still active being irradiated to the fluence beyond space charge sign inversion. This characteristic of VTS can be accounted for by the double peak electric field distribution in heavily irradiated detectors and the punch-through mechanism of current flow between the floating p{sup +} rings in the silicon bulk with high concentration of deep traps. It is shown that VTS operates as a potential divider up to the fluence of 1×10{sup 15} n{sub eq}/cm{sup 2} and it is at higher fluences that the detector stability is maintained only by the space charge limited current mechanism. -- Highlights: •Voltage terminating structure (VTS) operation in Si irradiated detector is studied. •Ring potentials and interring I–V characteristics are measured up to 1×10{sup 15} n{sub eq}/cm{sup 2}. •Double peak electric field maintains VTS action after space charge sign inversion. •VTS operates as a potential divider up to fluence 5×10{sup 14} n{sub eq}/cm{sup 2}. •At fluence 1×10{sup 15} n{sub eq}/cm{sup 2} VTS operation fails and it operates as a single ring.

  9. Real-time geometric scene estimation for RGBD images using a 3D box shape grammar

    Science.gov (United States)

    Willis, Andrew R.; Brink, Kevin M.

    2016-06-01

    This article describes a novel real-time algorithm for the purpose of extracting box-like structures from RGBD image data. In contrast to conventional approaches, the proposed algorithm includes two novel attributes: (1) it divides the geometric estimation procedure into subroutines having atomic incremental computational costs, and (2) it uses a generative "Block World" perceptual model that infers both concave and convex box elements from detection of primitive box substructures. The end result is an efficient geometry processing engine suitable for use in real-time embedded systems such as those on an UAVs where it is intended to be an integral component for robotic navigation and mapping applications.

  10. 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 ...

  11. 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.

  12. 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.

  13. 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.

  14. 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...

  15. Alkyl polyglucoside compound influences freshwater plankton community structure in floating field mesocosms.

    Science.gov (United States)

    Riera, Steven F; Cohen, Risa A

    2016-10-01

    Synthetic surfactants in cleaners and detergents commonly contaminate freshwater systems, therefore use of low-toxicity alternatives is becoming increasingly important. Alkyl polyglucosides (APGs) derived from natural products are less toxic than synthetic surfactants, and degrade rapidly reducing chemical exposure time. However, single species toxicity tests showed APGs have toxic effects on aquatic primary producers and zooplankton, and that species demonstrate different sensitivities to APGs. Furthermore, species unaffected by APGs directly may be indirectly affected by removal of a food source or changes in predator densities, thereby changing plankton community structure. To determine the effects of APGs on plankton communities under environmental conditions, floating mesocosms were deployed in a shallow pond in southeast Georgia, USA and dosed with 0, 0.01, 2.5, 5, or 10 mg L(-1) APG. Zooplankton community composition and abundance, phytoplankton abundance (as chlorophyll a), and water column dissolved oxygen concentration were determined weekly for 1 month. Zooplankton abundance decreased primarily due to loss of copepods, and community composition shifted toward small-bodied cladocerans (Bosmina sp.), and chlorophyll a concentrations declined by up to 81 % following exposure to APG concentrations of 2.5 mg L(-1) or greater. Concentrations of dissolved oxygen never dropped below 5.70 mg L(-1), but the observed declines of ~2 mg L(-1) could become stressful during periods of high water temperatures. Nevertheless, the APG-induced shift from copepod to cladoceran dominated communities and decrease in autochthonous carbon availability has important implications for food availability and quality to higher trophic levels such as planktivorous fishes.

  16. 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.

  17. 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...

  18. 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.

  19. A 3-D Time-Domain Coupled Model for Nonlinear Waves Acting on A Box-Shaped Ship Fixed in A Harbor

    Institute of Scientific and Technical Information of China (English)

    WANG Da-guo; ZOU Zhi-li; THAM Leslie George

    2011-01-01

    A 3-D time-domain numerical coupled model is developed to obtain an efficient method for nonlinear waves acting on a box-shaped ship fixed in a harbor.The domain is divided into the inner domain and the outer domain.The inner domain is the area beneath the ship and the flow is described by the simplified Euler equations.The remaining area is the outer domain and the flow is defined by the higher-order Boussinesq equations in order to consider the nonlinearity of the wave motions.Along the interface boundaries between the inner domain and the outer domain,the volume flux is assumed to be continuous and the wave pressures are equal.Relevant physical experiment is conducted to validate the present model and it is shown that the numerical results agree with the experimental data.Compared the coupled model with the flow in the inner domain governed by the Laplace equation,the present coupled model is more efficient and its solution procedure is simpler,which is particularly useful for the study on the effect of the nonlinear waves acting on a fixed box-shaped ship in a large harbor.

  20. 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).

  1. 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.

  2. A New Structure of Silicon-on-Insulator Metal-Oxide-Semiconductor Field Effect Transistor to Suppress the Floating Body Effect

    Institute of Scientific and Technical Information of China (English)

    朱鸣; 林青; 张正选; 林成鲁

    2003-01-01

    Considering that the silicon-on-insulator (SOI) devices have an inherent floating body effect, which may cause substantial influences in the performance of SOI device and circuit, we propose a novel device structure to suppress the floating body effect. In the new structure there is a buried p+ region under the n+ source and that region is extended to outside of the source, and this additional p+ region provides a path for accumulated holes to flow out of the body. Numerical simulations were carried out with Medici, and the output characteristics and gate characteristics were compared with those of conventional SOI counterparts. The simulated results show the suppression of floating body effect in the novel SOI device as expected.

  3. Installation of Large-span Single-layer Drum Shell with Spatial Changing Box-shaped Members%空间弯扭箱形构件大跨度单层筒壳安装技术

    Institute of Scientific and Technical Information of China (English)

    高玉兰; 王益民; 董巍

    2011-01-01

    The roof structure of Tiasijin West Railway Station is large-span grid shell structures which composed of spatial changing box-shaped members. The construction is difficult because of large-span and heavy weight. Based on the project practice, the division and multi-step lifting method with heavy lifting equipment is adopted. The triangle supporting tower is made of tube to shorten the construction period effectively. The high altitude accurate closure is completed by active control lifting technology, the controllability and safety of construction process are ensured by construction mechanics monitoring system.%天津西站中央站房屋盖结构首次为空间弯扭箱形截面构件交叉形成的大跨度联方网格筒壳结构,结构跨度大,质量大,施工控制难度大.结合工程实际情况,选用重型吊装设备分区分段吊装施工方案.通过选用圆管组成三角形支撑塔架,有效缩短工期.采用主动控制提升技术,完成高空合龙口高精度合龙,并引人施工力学监测系统,确保施工全过程安全、可控.

  4. Steam generation under one sun enabled by a floating structure with thermal concentration

    Science.gov (United States)

    Ni, George; Li, Gabriel; Boriskina, Svetlana V.; Li, Hongxia; Yang, Weilin; Zhang, Tiejun; Chen, Gang

    2016-09-01

    Harvesting solar energy as heat has many applications, such as power generation, residential water heating, desalination, distillation and wastewater treatment. However, the solar flux is diffuse, and often requires optical concentration, a costly component, to generate the high temperatures needed for some of these applications. Here we demonstrate a floating solar receiver capable of generating 100 ∘C steam under ambient air conditions without optical concentration. The high temperatures are achieved by using thermal concentration and heat localization, which reduce the convective, conductive and radiative heat losses. This demonstration of a low-cost and scalable solar vapour generator holds the promise of significantly expanding the application domain and reducing the cost of solar thermal systems.

  5. 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.

  6. 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.

  7. Influence of meso-substituted tetraphenylporphyrin derivatives structure on their supramolecular organization in floating layers and Langmuir-Blodgett films.

    Science.gov (United States)

    Kazak, Alexandr V; Usol'tseva, Nadezhda V; Yudin, Sergey G; Sotsky, Valentin V; Semeikin, Alexandr S

    2012-12-11

    To study the influence of structure peculiarities of porphyrin derivatives on their supramolecular organization in thin films, 15 new meso-substituted tetraphenylporphyrin derivatives and their metal complexes with substituents (-OC(4)H(9) or -OC(16)H(33)) in para or ortho positions were studied. The films of the studied compounds were obtained by the Langmuir-Schaefer method. The behavior of porphyrin derivatives at the water-air interface was analyzed, and the conformity of the influence of molecular structure on supramolecular organization in floating layers and Langmuir-Blodgett films was defined. The absorption of these films over a wide spectral range was analyzed. The supramolecular organization of meso-substituted tetraphenylporphyrin derivatives was modeled and specified with the help of X-ray diffraction analysis. It was determined that the formation of monomolecular layers is typical for the compounds with short lateral substituents or without substituents. Tetraphenylporphyrins with extensive substituents can form a monolayer only when zinc is included in the molecular structure.

  8. Floating shoulder

    OpenAIRE

    B. de Pablo Márquez; P. Castillón Bernal; I. Fuentes López

    2014-01-01

    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...

  9. Community structure of free-floating filamentous cyanobacterial mats from the Wonder Lake geothermal springs in the Philippines.

    Science.gov (United States)

    Lacap, Donnabella C; Smith, Gavin J D; Warren-Rhodes, Kimberley; Pointing, Stephen B

    2005-07-01

    Cyanobacterial mats were characterized from pools of 45-60 degrees C in near-neutral pH, low-sulphide geothermal springs in the Philippines. Mat structure did not vary with temperature. All mats possessed highly ordered layers of airspaces at both the macroscopic and microscopic level, and these appear to be an adaptation to a free-floating growth habit. Upper mat layers supported biomass with elevated carotenoid:chlorophyll a ratios and an as yet uncharacterized waxy layer on the dorsal surface. Microscopic examination revealed mats comprised a single Fischerella morphotype, with abundant heterocysts throughout mats at all temperatures. Molecular analysis of mat community structure only partly matched morphological identification. All samples supported greater 16S rDNA-defined diversity than morphology suggested, with a progressive loss in the number of genotypes with increasing temperature. Fischerella-like sequences were recovered from mats occurring at all temperatures, but some mats also yielded Oscillatoria-like sequences, although corresponding phenotypes were not observed. Phylogenetic analysis revealed that Fischerella-like sequences were most closely affiliated with Fischerella major and the Oscillatoria-like sequences with Oscillatoria amphigranulata.

  10. 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.

  11. Floating Ocean Platform

    Science.gov (United States)

    2003-08-15

    REVIEW, 83-89 Int. Hydrogr. Rev., 1986 ARANHA , JAP PESCE, CP, EFFECT OF THE 2ND-ORDER POTENTIAL IN THE SLOW-DRIFT OSCILLATION OF A FLOATING STRUCTURE...Technology Conference, Annual Proceedings, v 3, Construction & Installation/Field Drilling and Development Systems, 1997, OTC 8696, p 133-142 Aranha , J...Andre J.P. (Petrobras/Depro); Nishimoto, Kazuo; Aranha , J.A.P.; Morooka, Celso K., Minimization of vertical wave exciting force and heave motion of a

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. "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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.......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....../S. It is divided in 4 tasks: Task 1: Preliminary float design and economic considerations Task 2: Material characteristics Task 3: Preliminary experiences Task 4: The importance for wave energy The present report covers Task 1....

  2. Simulated floating zone method

    OpenAIRE

    Ozawa, Ryo; Kato, Yasuyuki; Motome, Yukitoshi

    2016-01-01

    This paper provides the simulated floating zone (SFZ) method that is an efficient simulation technique to obtain thermal equilibrium states, especially useful when domain formation prevents the system from reaching a spatially-uniform stable state. In the SFZ method, the system is heated up locally, and the heated region is steadily shifted, similar to the floating zone method for growing a single crystal with less lattice defect and impurity in experiments. We demonstrate that the SFZ method...

  3. 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.

  4. Floating substructure flexibility of large-volume 10MW offshore wind turbine platforms in dynamic calculations

    DEFF Research Database (Denmark)

    Borg, Michael; Hansen, Anders Melchior; Bredmose, Henrik

    2016-01-01

    Designing floating substructures for the next generation of 10MW and larger wind turbines has introduced new challenges in capturing relevant physical effects in dynamic simulation tools. In achieving technically and economically optimal floating substructures, structural flexibility may increase...

  5. Vertical structure and dominating factors of sand body during Late Triassic Chang 9 time of Yanchang Formation in Ordos Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    丁熊; 陈景山; 谭秀成; 林丹; 赵子豪; 姚泾利; 邓秀芹; 李元昊

    2015-01-01

    Based on a synthetic geological study of drilling, well logging and core observations, two main genetic types of Chang 9 sand body in Odors Basin were recognized, which included two effects, that is, delta environment and tractive current effects that lead to the development of mouth bar, distal bar, sheet sand and other sand bodies of subaerial and subaqueous distributary channel, natural levee, flood fan and delta front, and shore-shallow lake environment and lake flow transformation effects that result in the development of sandy beach bar, sheet sand and other sand bodies. Chang 9 sand body mainly developed five basic vertical structures, namely box shape, campaniform, infundibuliform, finger and dentoid. The vertical stacking patterns of multilayer sand body was complex, and the common shapes included box shape + box shape, campaniform + campaniform, campaniform + box shape, infundibuliform+infundibuliform, campaniform+infundibuliform, box shape+campaniform, box shape+infundibuliform, and finger+finger. Based on the analysis on major dominating factors of vertical structure of sand body, sedimentary environment, sedimentary facies and rise, fall and cycle of base level are identified as the major geological factors that control the vertical structure of single sand body as well as vertical stacking patterns and distribution of multistory sand bodies.

  6. Experimental study on the estimation method of hydrodynamic force acting on floating offshore structures; Futaishiki kaiyo kozobutsu ni kuwawaru ryutairyoku no suiteiho ni kansuru jikkenteki kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, K.; Kato, S. [Ship Research Inst., Tokyo (Japan); Koterayama, W. [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

    1996-04-10

    In the design of various floating offshore structures (FOS), the functionality, safety and amenity of FOSs were examined by estimating responses of FOSs to environmental external forces such as wave, wind and flow. In this paper, the estimation method of drag acting on the whole FOS was established by combining previous study results on hydrodynamic force acting on various bodies such as Reynolds number effect (RNE), 3-D effect (TDE) and interference effect (IE). This hydrodynamic force was also compared with that obtained from the experiment result on a FOS model for TLP to confirm the applicability of this estimation method. The estimation result on the drag coefficient in steady flow by considering RNE, TDE and IE well agreed with experimental one. The drag coefficient acting on FOSs in heaving could be estimated in practically sufficient accuracy by considering drag acting on not columns but only square columns. The estimation result on the drag coefficient acting on FOSs in surging by considering RNE, TDE and IE well agreed with experimental one. 12 refs., 10 figs., 1 tab.

  7. High pressure floating zone growth and structural properties of ferrimagnetic quantum paraelectric BaFe{sub 12}O{sub 19}

    Energy Technology Data Exchange (ETDEWEB)

    Cao, H. B. [Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Zhao, Z. Y. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States); Lee, M. [Department of Physics, Florida State University, Tallahassee, Florida 32306-3016 (United States); National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310-3706 (United States); Choi, E. S. [National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310-3706 (United States); McGuire, M. A.; Sales, B. C. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Zhou, H. D. [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States); Yan, J.-Q.; Mandrus, D. G. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States)

    2015-06-01

    High quality single crystals of BaFe{sub 12}O{sub 19} 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 BaFe{sub 12}O{sub 19} at 4 K and 295 K. At both temperatures, there exist local electric dipoles formed by the off-mirror-plane displacements of magnetic Fe{sup 3+} 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 T{sup 2} 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 SrTiO{sub 3}. The presence of the upturn in 1/ε indicates that BaFe{sub 12}O{sub 19} is a critical quantum paraelectric system with Fe{sup 3+} ions involved in both magnetic and electric dipole formation.

  8. Evaluation of a floating fish guidance structure at a hydrodynamically complex river junction in the Sacramento–San Joaquin River Delta, California, USA

    Science.gov (United States)

    Romine, Jason G.; Perry, Russell W.; Pope, Adam C; Stumpner, Paul; Liedtke, Theresa L.; Kumagai, Kevin K; Reeves, Ryan L

    2016-01-01

    Survival of out-migrating juvenile Chinook salmon (Oncorhynchus tshawytscha) in the Sacramento–San Joaquin River delta, California, USA, varies by migration route. Survival of salmonids that enter the interior and southern Delta can be as low as half that of salmonids that remain in the main-stem Sacramento River. Reducing entrainment into the higher-mortality routes, such as Georgiana Slough, should increase overall survival. In spring 2014, a floating fish-guidance structure (FFGS) designed to reduce entrainment into Georgiana Slough was deployed just upstream of the Georgiana Slough divergence. We used acoustic telemetry to evaluate the effect of the FFGS on Chinook entrainment to Georgiana Slough. At intermediate discharge (200–400 m3 s–1), entrainment into Georgiana Slough was five percentage points lower when the FFGS was in the on state (19.1% on; 23.9% off). At higher discharge (>400 m3 s–1), entrainment was higher when the FFGS was in the on state (19.3% on; 9.7% off), and at lower discharge (0–200 m3 s–1) entrainment was lower when the FFGS was in the on state (43.7% on; 47.3% off). We found that discharge, cross-stream fish position, time of day, and proportion of flow remaining in the Sacramento River contributed to the probability of being entrained to Georgiana Slough.

  9. Floating Versus Sinking

    Science.gov (United States)

    Vella, Dominic

    2015-01-01

    Small objects that are more dense than water may still float at the air-water interface because of surface tension. Whether this is possible depends not only on the density and size of the object, but also on its shape and surface properties, whether other objects are nearby, and how gently the object is placed at the interface. This review surveys recent work to quantify when objects can float and when they must sink. Much interest in this area has been driven by studies of the adaptations of water-walking insects to life at interfaces. I therefore discuss these results in the context of this and other applications.

  10. Floating offshore turbines

    DEFF Research Database (Denmark)

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

    2014-01-01

    phase applying (mostly) well-known technology, albeit in a new setting. DeepWind is a European research project based mostly on new technology. The concepts are described in some detail with emphasis on control and operation. Prospects are discussed including technical challenges and a performance...... metric of energy production per unit steel mass. Floating offshore wind turbines represent a promising technology. The successful operation of HyWind and WindFloat in full scale demonstrates a well advanced technology readiness level, where further development will go into refining the concepts, cost...

  11. 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.

  12. 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.

  13. 浅谈浮法玻璃熔窑用重油燃烧器的结构设计及其发展%A Discussion on Structural Design and Development of Heavy Oil Burner Used for Float Glass Furnace

    Institute of Scientific and Technical Information of China (English)

    张海梁; 傅鑫杰; 梅书霞; 谢峻林

    2011-01-01

    燃烧器是浮法玻璃熔窑中极为关键的热工设备.以浮法玻璃空气助燃技术以及全氧燃烧工艺为背景,从结构类型、工作原理、燃烧状态、优缺点以及发展历程等方面对几种具有代表性的重油燃烧器进行了详细介绍.%Burner is one of the crucial thermotechnical equipment in float glass melting furnace. Based on air - fuel combustion technology and oxy - fuel burning process for melting float glass, the principal technical aspects, such as structural type, working principle, combustion status, analysis of advantages and disadvantages and history of development of typical heavy oil burners were detailed reviewed.

  14. 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.

  15. Immunohistochemistry on freely floating fixed tissue sections.

    Science.gov (United States)

    Bachman, Julia

    2013-01-01

    Immunohistochemistry on free floating tissue sections is done for many reasons, all of which involve labeling tissue to visualize a certain cell type, protein, or structural component. Visualization is aided by mounting sections on microscope slides for stabilization, and is in most cases necessary for the appropriate use of objectives with a high numerical aperture and high degree of magnification.

  16. Structural analysis of floating collar for gravity cage system in the open sea%重力式网箱浮架结构的动力响应特性研究

    Institute of Scientific and Technical Information of China (English)

    单恒年; 董国海; 许条建

    2015-01-01

    Fish culture in the offshore fish cage has been received more and more attention recently, while there are bad sea conditions in offshore areas, so the safety of floating collar is very important for the design of fish cage system. To study dynamic response of floating collar under the wave loading, the numerical model of floating collar was built based on finite element method using the PIPE element, and a series of physical model test were conducted to validate the numerical model, and the results showed that the calculated results agreed well with the test results. Then the numerical simulation was performed to analyze the effects of the number of clamps and the breakage of mooring line on the dynamic response of floating collar. Finally the stress and deformation value of the connection points and deformation models of the floating collar of floating collar were obtained. The results indicated that the numerical model could accurately simulate the deformation of floating collar and the mooring line tension force. In addition, the stress and deformation value of floating collar was decreased with the increase in the number of clamps, and the stress value and mooring line force were decreased significantly to minimum when two mooring lines on the same side break. In conclusion, dynamic response is an important basis for structure optimization and analysis, and floating collar with 24 clamps is recommended.%利用离岸网箱进行水产养殖近年来受到了越来越多的重视,离岸区域海况条件恶劣,浮架结构的安全性对于网箱的设计具有极其重要的意义。为研究网箱浮架结构在动态波浪荷载作用下的动力响应,采用有限元法利用PIPE单元建立了浮架的数值模型,并根据物理模型试验结果对该数值模型进行验证,发现有限元模型的计算结果与模型试验结果吻合较好。基于该模型,重点分析了网箱的连接构件数量和个别锚绳发生断裂对浮架动力响应的

  17. 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.

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

    DEFF Research Database (Denmark)

    Christiansen, Søren; Knudsen, Torben; Bak, Thomas

    2011-01-01

    Offshore wind energy capitalizes on the higher and less turbulent wind speeds at sea. The use of floating structures for deeper waters is being explored. The control objective is a tradeoff between power capture and fatigue, especially that produced by the oscillations caused by the reduced...... 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...

  19. Impact on floating membranes

    OpenAIRE

    Vandenberghe, Nicolas; Duchemin, Laurent

    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...

  20. Serial floating point formatter

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, R. D.; Penner, W. A.

    1985-11-12

    A floating point formatter for changing fixed point serial digital data, such as that received by a seismic data acquisition system, is disclosed wherein fixed point serial digital data is received and scaled to remove any bias added by preamplification. The scaled data is shifted a predetermined number of bits and a resulting exponent is calculated. The shifted data signal and corresponding exponent are combined and further scaled to permit stacking the data without exceeding the system capacity.

  1. Floating point coprocessor upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Weber, T.

    1987-04-01

    A method was developed to increase the throughput of the Hewlett Packard, 98635A floating point processor equipped, model 236C computer. The increase was carried out in three phases each with a clock and or chip change during the modification. Two programs were written to test the results and evaluate the increases in performance made to the computer. The first one shows reduction in processing times of 34.3%, while the other recorded 34.6%.

  2. Collapsing floating-point operations

    OpenAIRE

    Defour, David

    2004-01-01

    This paper addresses the issue of collapsing dependent floating-point operations. The presentation focuses on studying the dataflow graph of benchmark involving a large number of floating-point instructions. In particular, it focuses on the relevance of new floating-point operators performing two dependent operations which are similar to "fused multiply and add". Finally, this paper examines the implementation cost and critical path reduction from this strategy.

  3. FLOPAK: FLOATING POINT PROGRAMING PACKAGE,

    Science.gov (United States)

    FLOPAK is a Packard-Bell 250 Computer semi-automatic, floating - point programing system which may be operated simultaneously in either of two modes...250 floating - point system available which may be used in real-time control. The system was originally designed to solve a real-time communication problem....The first is a non-time optimized mode which may be used by inex perienced coders; the second mode is a high-speed, fully time-optimized floating

  4. A Study on Floating-point Systolic Array Structure and FPGA Implementation Based on QR_RLS Algorithm%QR_RLS算法的浮点脉动阵结构研究与FPGA实现

    Institute of Scientific and Technical Information of China (English)

    杜鹤; 买培培; 苏涛; 张子敬

    2011-01-01

    With the coninuous development of radar signal processing technology, more requirements for parallel processing and precision have been put forward. Systolic structure is one of the key structures of parallel processing in radar signal processing. In this paper, a floating-point systolic structure based on QR_RLS algorithm is described. To improve computing speed and take advantage of multiplier resources, a custom floating-point format and the floating-point unit design in the format are introduced. Also,the square root algorithm and computing speed are both improved. This systolic structure is implemented on FPGA, and the results show that on the premise of improved computing accuracy, the systolic structure in the custom floating-point format reduces the occupancy of the corresponding resources. The result can be used as reference in real-time signal processing.%随着雷达信号处理技术的不断发展,对实时并行性和处理精度都提出了更高的要求,脉动阵结构是雷达信号处理中一种关键并行处理结构.文中介绍了一种基于QR_RLS算法的浮点脉动阵结构.为了提高运算速度,充分利用资源,引入了自定义浮点格式及该格式下的浮点运算单元的设计,并改进了平方根算法,提高了运算精度.在FPGA上实现了这种脉动阵结构,结果表明这种自定义浮点格式的脉动阵结构在提高了运算精度的同时,降低了相应的资源占用率,对实时信号处理的工程设计具有较高的参考价值.

  5. 整体和浮置式道床隧道结构动应力计算分析%Calculation and Analysis on Dynamics Stress of Tunnel Structure with Integral and Floating Slab Track

    Institute of Scientific and Technical Information of China (English)

    杨宁; 耿传智

    2015-01-01

    By using the finite element software ANSYS, the paper establishes the 3D model under the tunnel structure conditions of slab track with monolithic and floating slab. By inputing the corresponding measured wheel-rail force, the paper calculates the tunnel substructure dynamic stress distribution and quantity under the 2 different track beds. The paper makes conclusion that the tunnel substructure dynamic stress effect for the floating slab track compared to the monolithic track bed is much smaller, and both horizontal and longitudinal dynamic stress distribution is more uniform and reasonable. From a long-term point of view and in the premise of having satisfied the vibration and noise reduction functions, the steel spring floating slab track structure can effectively reduce wheel-rail force, therefore reducing the additional settlement of the tunnel structures.%利用ANSYS有限元软件,建立了整体道床和浮置板道床情况下隧道结构三维模型,通过对应实测轮轨力的输入,计算得到2种道床下隧道下层结构动应力的分布情况和大小。结论是,浮置板道床对于下层隧道结构动应力影响相较于整体道床小很多,且无论横向还是纵向动应力分布都更加均匀合理。从长远来看,钢弹簧浮置板轨道结构在满足减振降噪的功能前提下,可以有效减小轮轨力造成的隧道结构附加沉降。

  6. The Stability Evaluation Research of Many Floating Structures at Spread Mooring System%多锚链系泊浮体的稳定性评估

    Institute of Scientific and Technical Information of China (English)

    缪馥星; 杨黎明; 董新龙

    2012-01-01

    In this paper, based on the catenary equation of a single chain, quasi static governing equation of Multi Chain mooring floating body or a ship are established. The relationship between multiple anchor floating drift rate and horizontal mooring force are given in the known environmental load. The calculation results can be used the theory reference to design collision avoidance of offshore facilities.%基于单根锚链的悬链线方程,建立整体作用下的叠加型多锚链系泊浮体的准静态控制方程,给出了一定环境载荷作用下,多锚链浮体的漂移量与水平系泊力间的关系.计算结果对海上防撞设施的设计提供理论参考.

  7. Floating JMaRT

    CERN Document Server

    Bossard, Guillaume

    2014-01-01

    We define a new partially solvable system of equations that parametrises solutions to six-dimensional N=(1,0) ungauged supergravity coupled to tensor multiplets. We obtain this system by applying a series of dualities on the known floating brane system, imposing that it allows for the JMaRT solution. We construct an explicit multi-centre solution generalising the JMaRT solution, with an arbitrary number of additional BPS centres on a line. We describe explicitly the embedding of the JMaRT solution in this system in five dimensions.

  8. Modeling of fluid resonance in-between two floating structures in close proximity%近距两浮体间流体共振分析

    Institute of Scientific and Technical Information of China (English)

    Chao-bang YAO; Wen-cai DONG

    2015-01-01

    In this study, we conducted numerical simulations of fluid resonance in-between two floating structures based on potential theory assessing the effect of fluid viscosity by including the artificial damping force. The numerical results of two adjacent Barges systems and Barge & Wigley systems were compared with experimental data of those of the viscous fluid mod-el based on Reynolds average Navier-Stokes equations (RANSE). It can be observed that the conventional potential flow model (without artificial damping force) significantly over-estimated the wave height and forces around the resonant frequencies. Re-sults of the present method with an appropriate damping coefficient supported the available data, confirming the importance of the viscous damping effect on strong hydrodynamic interaction between the floating structures. Furthermore, influences of lat-eral clearances, wave heading angles, and ships’ motions on the wave surface elevations were analyzed. Validation and applica-tion of methods to estimate the fluid resonant frequencies and modes were also conducted. Generally speaking, Molin’s simpli-fied theory can give an accurate estimation of resonant frequencies and serve as a practical tool to analyze the fluid resonant phenomena of gaps in-between a two Barge system and Wigley & Barge system in close proximity.%目的:基于三维线性势流理论,通过在近距两浮体间的自由液面上引入“粘性耗散系数”,建立计及粘性影响的波浪中近距两浮体水动力干扰效应分析数值计算方法,以准确分析两浮体的干扰力及浮体间液面升高;并探讨“粘性耗散系数”的确定方法、两浮体间流体共振频率及共振模式的数值计算方法。  方法:1.通过理论分析,在三维线性势流理论基础上,引入流体“粘性耗散”(公式2、10~12、18和19)以准确模拟近距两浮体波浪中的水动力及浮体间液面抬升;2.采用雷诺应力平均方程

  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

    . In order to assess the technical and economic feasibility of this novel concept, a comprehensive simulation tool for modeling of the floating vertical axis wind turbine is needed. This work presents the development of a coupled method for modeling of the dynamics of a floating vertical axis wind turbine......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....... This integrated dynamic model takes into account the wind inflow, aerodynamics, hydrodynamics, structural dynamics (wind turbine, floating platform and the mooring lines) and a generator control. This approach calculates dynamic equilibrium at each time step and takes account of the interaction between the rotor...

  10. 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.

  11. Development of floating strip micromegas detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bortfeldt, Jonathan

    2014-04-28

    Micromegas are high-rate capable, high-resolution micro-pattern gaseous detectors. Square meter sized resistive strip Micromegas are foreseen as replacement of the currently used precision tracking detectors in the Small Wheel, which is part of the forward region of the ATLAS muon spectrometer. The replacement is necessary to ensure tracking and triggering performance of the muon spectrometer after the luminosity increase of the Large Hadron Collider beyond its design value of 10{sup 34} cm{sup -2}s{sup -1} around 2020. In this thesis a novel discharge tolerant floating strip Micromegas detector is presented and described. By individually powering copper anode strips, the effects of a discharge are confined to a small region of the detector. This reduces the impact of discharges on the efficiency by three orders of magnitude, compared to a standard Micromegas. The physics of the detector is studied and discussed in detail. Several detectors are developed: A 6.4 x 6.4 cm{sup 2} floating strip Micromegas with exchangeable SMD capacitors and resistors allows for an optimization of the floating strip principle. The discharge behavior is investigated on this device in depth. The microscopic structure of discharges is quantitatively explained by a detailed detector simulation. A 48 x 50 cm{sup 2} floating strip Micromegas is studied in high energy pion beams. Its homogeneity with respect to pulse height, efficiency and spatial resolution is investigated. The good performance in high-rate background environments is demonstrated in cosmic muon tracking measurements with a 6.4 x 6.4 cm{sup 2} floating strip Micromegas under lateral irradiation with 550 kHz 20 MeV proton beams. A floating strip Micromegas doublet with low material budget is developed for ion tracking without limitations from multiple scattering in imaging applications during medical ion therapy. Highly efficient tracking of 20 MeV protons at particle rates of 550 kHz is possible. The reconstruction of the

  12. 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.

  13. 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

  14. 漂浮式微型波力发电装置原理与结构%Principle & Structure of Floating Micro-type Device for Wave-activated Power Generation

    Institute of Scientific and Technical Information of China (English)

    苏毅; 张涛; 张镇; 林梅

    2013-01-01

      为了满足偏远岛屿小功率用电保障需求,根据波浪能特点,提出一种新型漂浮式微型波力发电装置。利用重锤惯性定心原理,建立浮动“机架”,解决漂浮体内部相对固定问题;采用机-电直接转换系统,提高波浪能的利用效率;研究系统的原理与结构,分析系统的功能特点和主要运动参数。研究结果表明,漂浮式微型波力发电装置具有结构原理新颖、传动效率高、传动质量好与轻巧便携等优点。该研究为漂浮式微型波力发电装置的研发与应用奠定了基础。%To meet the needs for small power electricity utilization on islands,and based on the characteristics of ocean wave energy, a new floating micro⁃type device for wave⁃activated power generation is proposed. In order to solve the problem of station being fixed in buoy device,a floating frame is used by the inertial stabilization principle of ballast. The utilization efficiency of ocean wave energy is raised by direct machinery⁃electricity conversion system. And then,the structural principles and functional characteristics of the power generation system,especially main movement parameters of the system,are described for further research and application. Results show advantages of the floating micro⁃type device for wave⁃activated power generation including novel structural principle,high drive efficiency, good drive effect,easy carrying,and so on. The study could provide sound basis for the research&development and application of the proposed floating micro⁃type device.

  15. 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.

  16. 时滞相关Logistic函数浮点数据模糊加密稀疏集构造%Sparse Set Structure of Floating-point Data Fuzzy Encryption Based on Delay Dependent Logistic Function

    Institute of Scientific and Technical Information of China (English)

    李晓靖

    2015-01-01

    提出一种基于时滞相关Logistic函数线性调频采样的浮点数据模糊加密算法优化技术,给出时滞相关Logistic函数及相关定义,研究了浮点数据的模糊编码算法,设计实时交互网络的浮点数据模糊加密方案,实现密钥稀疏集构造,采用基于稀疏矩阵的存储格式下的时滞相关Logistic函数浮点数据加密运算,构造密钥稀疏集,优化了算法性能。仿真结果表明,算法数据加密和解密性能较好,具有较高的数据吞吐量,能实现对大数据库的数据加密,提高了密文的不可预测性。%A sample Logistic function linear frequency based on the delay of floating-point data encryption algorithm for fuzzy optimization techniques is proposed, given the delay dependent Logistic function and definition of fuzzy coding algo⁃rithm, floating-point data, floating-point data design of real-time interactive network fuzzy encryption scheme is obtained. Realize the key sparse set structure, using encryption delay dependent Logistic function point data storage format based on the sparse matrix, key sparse sets are constructed, the performance of the algorithm is optimized. The simulation results show that, the algorithm of data encryption and decryption performance is good, the data throughput is higher, it can realize the data encryption of database, the cipher text is unpredictable.

  17. 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.

  18. Motion Characteristics of Novel Floating Foundation for Offshore Wind Turbine

    Institute of Scientific and Technical Information of China (English)

    李嘉文; 唐友刚; 王宾

    2016-01-01

    A novel floating foundation to support the NREL offshore 5 MW wind turbine was designed conceptu-ally by combining the characteristics of barge and Spar. The main focus was structural design and hydrodynamic modelling. Based on this novel floating foundation, the hydrodynamic performance was investigated in the fre-quency domain and time domain by using the wave analysis software HydroD and DeepC from Det Norske Veritas. The frequency domain analysis was conducted to investigate the effects of the incident wave angle and water depth. The time-domain analysis was carried out to evaluate the response of the floating foundation under a selected op-erational condition. The hydrodynamic performances of this floating foundation with respect to time series and re-sponse spectra were also investigated in this study.

  19. 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.

  20. 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.

  1. 海上浮动风力发电机组支撑结构的动力学与振动控制研究%Analysis of offshore support structure dynamics and vibration control of floating wind turbines

    Institute of Scientific and Technical Information of China (English)

    Luo Ningsu

    2012-01-01

    Offshore wind energy is one of the fastest growing powers in the field of renewable energy.An offshore wind farm situated sufficiently far away from the coast can generate more wind power and will have a longer operation life since the winds are stronger and more consistent than those on or near the coast.It can also avoid some major problems of the traditional wind farms like the visual and noise impacts and potential damage to wildlife.From the technical point of view,it is difficult to anchor the wind turbines directly on the seabed in deep water.Thus,new constructive solutions based on floating support structures are proposed.One of the main challenges is to reduce the fatigue of a floating offshore wind turbine so as to guarantee its proper functioning under the constraints imposed by the floating support structures subject to a greater range of motion than that of the fixed-bottom support structures.This paper analyzes the loads and dynamic response of floating support structures and addresses the problem of designing semiactive controllers to mitigate the dynamic wind and wave loads on floating wind turbines.The output feedback control strategy is proposed to avoid the dependence on the knowledge of the system states.The H∞ output feedback control technique is used for formulating the semiactive control law,which is implemented using a tuned liquid column damper (TLCD).Numerical simulation is done to verify the obtained results.%海上风能是可再生能源领域中增长最快的一种能源.与海岸边与近海处相比,远离海岸处的风更强、且更稳定,因此坐落在离海岸足够远处的海上风电场可以产生更多的风电、具有更长的运行寿命.它可以避免传统风电场的一些重大问题,比如视觉和嗓音影响、对野生动物的潜在伤害等;但从技术角度看,直接在海底固定风力涡轮机是比较困难的,为此,提出了一些基于浮动支撑结构的建设性解决方案.这些方案面

  2. 利用调频质量阻尼器结构实现海上漂浮式风力机的稳定性控制%Stability Control of Floating Wind Turbines With Tuned Mass Damper Structure

    Institute of Scientific and Technical Information of China (English)

    穆安乐; 王超; 刘宏昭; 张明洪; 张玉龙

    2013-01-01

    The flexible multi-body offshore floating wind turbines work under the conditions of combined effects of random wind and wave loads, the structural dynamic stability analysis and control is one of the key issues to be solved. Considering the six oscillation forms produced by aero-hydro-structure coupling effects, the Spar-structure of the floating wind turbine was used as a prototyping system. Focusing on two kinds phenomena of the pitching and heaving motions, the active structural control form of putting the tuned mass damper (TMD) on the cabin of wind turbine was proposed, and a 3-DoF floating wind turbine precise control model was established, where the wind loads action on blades and the tower was taken into account for the external excitation of wind, and the wave load was modeled by using the Morison equation. Based on this model, dynamic responses of pitching movement were analyzed under the conditions of action loads of random wind-wave which have the biggest effects on the performances of floating wind turbine, and the linear quadratic regulator (LQR) controller design was achieved to realize the control objectives of the minimum displacement, velocity and acceleration for wind turbine tower with the minimum energy consumption. Taking a 5-MW floating wind turbine as an example, the dynamic response of pitching movement before and after the control were simulated and analyzed. The simulation results show that the TMD control can effectively reduce 55%of the largest tower vibration displacement, and can quickly weaken the tower vibration and return to stable state.%海上漂浮式风力机是在随机性风载荷和浪载荷联合作用下工作的,其结构动态稳定性分析与控制是亟待解决的关键问题之一。考虑到气动-水动-结构耦合作用而产生6种摇荡形式,该文选择Spar结构的漂浮风力机作为样机系统。针对其纵摇和垂荡这2种摇荡现象,提出了以调频质量阻尼器(tuned mass damper,TMD

  3. 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.

  4. 阻尼钢弹簧浮置板轨道结构隔振性能分析%Analysis of Vibration Isolation Performance of Floating Slab Track Structure with Damping Steel Springs

    Institute of Scientific and Technical Information of China (English)

    梁上燕; 肖安鑫; 耿传智

    2013-01-01

    Floating slab track structure with damping steel springs is an effective track structure for vibration reduction. In order to analyze its vibration isolation performance, a dynamic analysis model of this structure was set up. Its harmonic response was analyzed, and its dynamic transfer characteristics under harmonic excitation were analyzed. The actual impact between wheel and rail was simulated. Influence of different length of the floating slab, stiffness and damping of vibration isolators, and different load positions on the vibration isolation performance of the structure was studied. This work provides a reference for further improvement of railroad structures.%  阻尼钢弹簧浮置板轨道结构已证实是一种有效的减振降噪轨道结构。为分析其隔振性能,通过建立阻尼钢弹簧浮置板轨道结构动力分析模型,对其进行谐响应分析,模拟列车运行时轮轨间实际冲击,研究其在简谐激励下的动力传递特性,并分别考虑浮置板长度、隔振器刚度和阻尼,以及不同载荷作用位置对浮置板隔振性能的影响。计算和分析对于今后轨道结构的进一步改善具有参考的价值。

  5. 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 ...

  6. 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...... promise a good maintenance of the operating point of the floating-gate devices. Examples of utilizing of such bias sources in low-noise sensor preamplifiers are discussed....

  7. 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.

  8. NULL Convention Floating Point Multiplier

    Directory of Open Access Journals (Sweden)

    Anitha Juliette Albert

    2015-01-01

    Full Text Available Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation.

  9. NULL convention floating point multiplier.

    Science.gov (United States)

    Albert, Anitha Juliette; Ramachandran, Seshasayanan

    2015-01-01

    Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation.

  10. NULL Convention Floating Point Multiplier

    OpenAIRE

    Anitha Juliette Albert; Seshasayanan Ramachandran

    2015-01-01

    Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to p...

  11. 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)

  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. 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.

  14. 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...

  15. 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.

  16. Performance Evaluation of an Axysimmetric Floating OWC

    DEFF Research Database (Denmark)

    Alves, M. A.; Costa, I. R.; Sarmento, A. J.

    2010-01-01

    The present paper reports a numerical study concerning a device for wave energy conversion which uses the relative vertical displacement between two bodies to absorb wave energy. Basically the device under analysis is a floating body with an internal oscillating water column (OWC), in which...... the wave energy is extracted through the relative displacement between the structure and the internal free surface. The paper presents in detail the methodology applied to define, from the hydrodynamic point of view, the device geometry. The numerical code used is a three-dimensional radiation...

  17. 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... that the system performs well when it is just submerged. As float velocity decreases with increase in float size, transmission coefficient increases with increase in float size. The influence of wave period on wave attenuation is remarkable compared to other...

  18. 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.

  19. Frequency-domain characteristics of aerodynamic loads of offshore floating vertical axis wind turbines

    DEFF Research Database (Denmark)

    Borg, Michael; Collu, M.

    2015-01-01

    The re-emerging interest in vertical axis wind turbines for floating offshore applications has led to a need to investigate the relatively complex dynamics of such floating offshore structures. Through the use of a coupled model of dynamics this article investigates the frequency-domain character......The re-emerging interest in vertical axis wind turbines for floating offshore applications has led to a need to investigate the relatively complex dynamics of such floating offshore structures. Through the use of a coupled model of dynamics this article investigates the frequency-domain...... characteristics of floating vertical axis wind turbine aerodynamic loads. The impact of platform induced motion on aerodynamic loads is discussed in detail, with results indicating an increase in aerodynamic loads of several orders of magnitude over the range of frequencies usually containing significant wave...

  20. 基于BP神经网络的起重船臂架结构优化设计%Floating Crane Arm Frame Structure Optimization Design Based on BP Neural Network

    Institute of Scientific and Technical Information of China (English)

    张成凤; 徐长生

    2012-01-01

    For the structure design and calculation of floating crane arm, BP neural network algorithm is used to simulate the relations between the arm frame structure optimization design variables and arms frame structure stress and displacement, and calling the minimize function of MATLAB optimal toolbox to optimized the arm constraint conditions and the objective function. Comparing and analyzing the result after optimization and the values before optimization, the BP neural network optimization algorithm is fully verified.%针对起重船臂架结构设计计算,采用BP神经网络算法模拟出臂架结构优化设计变量与臂架结构应力、位移之间的映射关系,并调用MATLAB优化工具箱中的最小化函数对臂架结构的约束条件以及目标函数进行优化处理,并将优化后的结果与优化之前的数值进行对比分析,充分地验证了BP神经网络优化算法的优越性.

  1. 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.

  2. Underwater shock response analysis of a floating vessel

    NARCIS (Netherlands)

    Aanhold, J.E. van; Lemmen, P.P.M.

    1996-01-01

    The response of a surface vessel to underwater shock has been calculated using an explicit finite element analysis. The analysis model is two-dimensional and contains the floating steel structure, a large surrounding water volume and the free surface. The underwater shock is applied in the form of a

  3. Underwater shock response analysis of a floating vessel

    NARCIS (Netherlands)

    Aanhold, J.E. van; Meijer, G.J.; Lemmen, P.P.M.

    1998-01-01

    The response of a surface vessel to underwater shock has been calculated using an explicit finite element analysis. The analysis model is two-dimensional and contains the floating steel structure, a large surrounding water volume and the free surface. The underwater shock is applied in the form ot a

  4. 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.

  5. Floating Charge%Floating Charge--浮动抵押

    Institute of Scientific and Technical Information of China (English)

    鲍为民

    2004-01-01

    "Floating Charge"来源于英美法系,它将担保设立在公司的全部财产之上(该担保甚至可及于公司未来之财产),在结晶前公司对财产享有处分权.通过介绍Floating Charge的创立和发展变化,从设定和实施两个方面详细考察了该制度的具体内涵.最后通过和大陆法系财团抵押制度的对比,提出应在我国引进浮动抵押,完善企业担保制度.

  6. The Application Modular Floating Pontoon to Support Floods Disaster Evacuation System in Heavy Populated Residential Area

    Directory of Open Access Journals (Sweden)

    Ahmad Fauzan Zakki

    2014-10-01

    Full Text Available During floods disaster in the heavy populated residential area, the lack of existing life saving appliances system such as rubber boat and wooden boat were not able to evacuate the disaster victims spontaneously in mass. The condition might be explained since the rubber boat and wooden boat have limited occupant capacity. Based on the conditions, the main objectives of the research are focused on the evaluation of the application of modular floating pontoon as multipurpose floating equipment to support floods disaster evacuation process. The investigation of the modular floating pontoon performance such as hydrostatics characteristics, the equilibrium condition and the intact stability was studied using strip theory and Krylov’s method. Furthermore, the strength analysis of the modular floating pontoon structure was calculated using finite element method. The results show that the modular floating pontoon is reliable to support the evacuation process.

  7. 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.

  8. A laboratory study of floating lenticular anticyclones

    Science.gov (United States)

    Le Gal, Patrice; de La Rosa, Hector; Cros, Anne; Cruz-Gomez, Raúl; Le Bars, Michael

    2014-11-01

    Oceanic vortices play an important role in the redistribution of heat, salt and momentum in the oceans. Among these vortices, floating lenses or rings are often met in the meanders of warm currents. For instance the North Brazil Current rings are among the most intense and large anticyclonic vortices on Earth. In order to better describe these vortices, we propose here a laboratory study of these floating anticyclonic lenses. A blob of fresh water is slowly injected near the surface of a rotating layer of homogeneous salted water. Because of the opposite effects of rotation that tends to generate columnar structures and density stratification that spreads light water on the surface, the vortices take a finite size three dimensionnal typical shape. Visualization and PIV measurements of the shape, aspect ratios and vorticity profiles are compared to analytical predictions that use first a simple solid body rotation model and then a more realistic isolated Gaussian vorticity field inside the anticyclones. This work was carried out within the framework of a bilateral cooperation between CNRS (France) and CONACYT (Mexico).

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

    DEFF Research Database (Denmark)

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

    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 behavior of the system. Model predictive control combined with a state estimator finds the optimal rotor blade...... compared to a baseline floating wind turbine controller at the cost of more pitch action....

  10. A CMOS floating point multiplier

    Science.gov (United States)

    Uya, M.; Kaneko, K.; Yasui, J.

    1984-10-01

    This paper describes a 32-bit CMOS floating point multiplier. The chip can perform 32-bit floating point multiplication (based on the proposed IEEE Standard format) and 24-bit fixed point multiplication (two's complement format) in less than 78.7 and 71.1 ns, respectively, and the typical power dissipation is 195 mW at 10 million operations per second. High-speed multiplication techniques - a modified Booth's allgorithm, a carry save adder scheme, a high-speed CMOS full adder, and a modified carry select adder - are used to achieve the above high performance. The chip is designed for compatibility with 16-bit microcomputer systems, and is fabricated in 2 micron n-well CMOS technology; it contains about 23000 transistors of 5.75 x 5.67 sq mm in size.

  11. The Clouds That Float By

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    AS I walk toward the autumn of my life, I begin to realize that everything in the world seems to have moved in a cycle, like the four seasons that continue to change and renew outside my window. But I am still seated in front of my window, observing the floating clouds at the ends of the earth. Some of them float from the future, some from the past. They join at the head and the tail of the universe; it is hard to tell the dragon’s head from the dragon’s tail. Things are always like this—the beginnings and the endings are sometimes interchangeable; the things that you think have gone by, have gone far away or completely vanished will suddenly appear before you like old acquaintances. Perhaps it might be the second generation accompanied by the shadows of the first.

  12. Estimating transmitted waves of floating breakwater using support vector regression model

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Hegde, A.V.; Kumar, V.; Patil, S.G.

    Planning and design of coastal protection works like floating breakwaters requires information about the performance characteristics of the structure in reducing the wave energy. They can be used as a temporary protection for offshore activities...

  13. 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.

  14. Computation accuracy of flow conditions around a very large floating structure using a multi-layer model. Comparison with experimental results; Taso model ni yoru choogata futai mawari no ryukyo keisan seido ni tsuite. Jikken tono hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Kyotsuka, Y. [Kyushu University, Fukuoka (Japan); Omori, H.; Nakagawa, H.; Kobayashi, M. [Mitsui Engineering and Shipbuilding Co. Ltd., Tokyo (Japan)

    1996-04-10

    As one of the environmental problems in sea areas surrounding a very large floating structure (VLFS), change in flow condition is important, and it is one of the factors dominating the prediction of succeeding diffusion and ecosystems. Although a multi-layer model is in wide use for computation of flow condition and diffusion in one inner bay, its applicability should be reexamined because of no consideration of VLFSs. In this study, flow velocity profiles around a barge were then measured through the towing test of a barge in shallow water, and compared with computation results using a multi-layer model. The multi-layer model computed the flow velocity profiles by dividing the flow region to be computed into normal one and that under VLFS, and determined pressures under VLFS by 2-D Poisson`s equation. Slip condition was used as boundary condition at the bottom considering the number of layers under VLFS. Further numerical computation was conducted by 2-D MAC method, in particular, to compare flow around the wake of VLFS with experimental one. Both computation results well agreed with experimental one. 3 refs., 9 figs., 1 tab.

  15. 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.

  16. 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.

  17. Thickness monitor for floated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Ricketts, J.; Grecu, G.M.

    1989-10-31

    This patent describes apparatus for determining the thickness of a layer of aerated sludge floating on a layer of a heavier liquid in a tank. It comprises: a frame means which can be positioned to extend vertically into the tank; horizontally-extending indicator means supported by and moveable vertically with respect to a portion of the frame means extending vertically into the tank. The indicator means being selectively positionable at the highest level of sludge in the tank; horizontally-extending lower base means attached to the frame means at or near the bottom thereof; horizontally-extending upper base means attached to the frame means at or near the top thereof; and a line carrying a float means. The line being movable secured at the upper base means and the lower base means. The float means being floatable on the liquid and including a horizontally-extending portion presenting an upwardly directed generally planar surface, which surface will be parallel to the interface of the sludge and liquid.

  18. Model-Based Control of a Ballast-Stabilized Floating Wind Turbine Exposed to Wind and Waves

    DEFF Research Database (Denmark)

    Christiansen, Søren

    2013-01-01

    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 hy-drodynamics and wave induced loads. In contrast to a bottom fixed wind turbine, the floating structure......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 effi-ciency in order to reduce the total cost of the energy. The latest offshore development is the floating......, 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...

  19. 14 CFR 27.753 - Main float design.

    Science.gov (United States)

    2010-01-01

    ... 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 differential... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 27.753 Section...

  20. 14 CFR 29.753 - Main float design.

    Science.gov (United States)

    2010-01-01

    ... 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 differential... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 29.753 Section...

  1. 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

  2. Evaluation of three types of structured floating plastic media in moving bed biofilters for total ammonia nitrogen removal in a low salinity hatchery recirculating aquaculture system

    Science.gov (United States)

    Three different commercially available structural plastic media were evaluated in triplicate in moving bed toriod filters under low salinity (11-12 ppt) warm water culture conditions and two different feed loading rates. The culture system consisted of nine separate modules that include a double dra...

  3. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 15 2010-07-01 2010-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Storage Vessels § 65.45 External floating roof converted into an...

  4. Surface Tension Supported Floating of Heavy Objects: Why Elongated Bodies Float Better?

    CERN Document Server

    Bormashenko, Edward

    2015-01-01

    Floating of bodies heavier than the supporting liquid is discussed. Floating of cylindrical, ellipsoidal bodies and rectangular plates possessing lateral dimensions smaller than the capillary length is treated. It is demonstrated that more elongated bodies of a fixed volume are better supported by capillary forces, due to the increase in the perimeter of the triple line. Thus, floating of metallic needles obtains reasonable explanation.

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

    DEFF Research Database (Denmark)

    Andersen, Morten Thøtt; Hindhede, Dennis; Lauridsen, Jimmy

    2015-01-01

    , 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......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...

  6. 14 CFR 27.751 - Main float buoyancy.

    Science.gov (United States)

    2010-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 27.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight of the rotorcraft in...

  7. 14 CFR 29.751 - Main float buoyancy.

    Science.gov (United States)

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight of the rotorcraft...

  8. Hydroelasticity of a Floating Plate

    DEFF Research Database (Denmark)

    Chen, X.; Jensen, Jørgen Juncher; Cui, W.;

    2003-01-01

    The membrane forces are included in the hydroelastic analysis of a floating plate undergoing large vertical deflections in regular monochromatic multidirectional waves. The first-order vertical displacements induced by the linear wave exciting forces are calculated by the mode expansion method...... in the frequency domain. The second-order vertical displacements induced by the membrane forces are calculated by the von Karman plate theory. The results show that the membrane contribution both in terms of the axial stresses and the effect on the bending stresses can be important...

  9. Floating patella associated with lymphoedema

    Science.gov (United States)

    Vun, Shen Hwa; Bayam, Levent; Drampalos, Efstathios; Jesry, Mohammed; Fadel, George

    2015-01-01

    Ipsilateral injury of more than one component of the knee extensor apparatus is rare. It is mostly associated with previous trauma, surgery, immunosuppression therapy and systemic disease. We present the first documented case of a spontaneous bifocal disruption of the knee extensor apparatus (i.e. floating patella) associated with lymphoedema. This case highlights the importance of considering lymphoedema as another risk factor for rupture of the knee extensor apparatus. It also highlights the importance of assessing all components of the knee extensor apparatus in patients presenting with acute knee injuries. PMID:25802253

  10. Research and Design of High Voltage LDMOS with Single Layer Floating Field Plate Structure%具有单层浮空场板的高压LDMOS器件研究

    Institute of Scientific and Technical Information of China (English)

    文帅; 乔明

    2015-01-01

    In the paper, the high voltage RESURF-LDMOS with single layer floating field plate has been researched andoptimized through simulation tool Silvaco.The simulation results show that: for the high voltage device with RESURF structure, field plates have a significant effect for the optimization of device surface electric field, the number and the length of field plates have great influence on the BV of device, and field plates can reduce the peak of electric field. Also, field plates can increase the tolerance range of the P-top dose of the double RESURF-LDMOS, and this lead to the change of the on resistance of device.%通过器件仿真软件Silvaco对带单层浮空场板的高压LDMOS(Lateral Double-diffused MOSFET)器件进行了设计与优化。仿真结果表明:对于击穿电压为600 V的RESURF(reduced surface field)LDMOS器件,场板能够有效地优化器件表面电势分布,降低电场峰值,提高器件的击穿电压。其中场板的数量、长度等参数对高压RESURF-LDMOS器件的耐压有较大影响。并且场板结构增加了double RESURF器件P-top剂量的容差范围,影响了器件的导通电阻。

  11. Floating point numbers are real numbers

    OpenAIRE

    Mascarenhas, Walter F.

    2016-01-01

    Floating point arithmetic allows us to use a finite machine, the digital computer, to reach conclusions about models based on continuous mathematics. In this article we work in the other direction, that is, we present examples in which continuous mathematics leads to sharp, simple and new results about the evaluation of sums, square roots and dot products in floating point arithmetic.

  12. Towards sensible floating-point arithmetic

    Energy Technology Data Exchange (ETDEWEB)

    Cody, W.J.

    1980-01-01

    Efforts to promote the development of high-quality transportable numerical software show that few, if any, of the floating-point arithmetic systems in existing computers are completely satisfactory for serious numerical computation. Examination of the defects in these systems leads to specifications for a sensible floating-point system from a numerical analyst's viewpoint. 1 table.

  13. Floating plant dominance as a stable state

    Science.gov (United States)

    Scheffer, Marten; Szabó, Sándor; Gragnani, Alessandra; van Nes, Egbert H.; Rinaldi, Sergio; Kautsky, Nils; Norberg, Jon; Roijackers, Rudi M. M.; Franken, Rob J. M.

    2003-01-01

    Invasion by mats of free-floating plants is among the most important threats to the functioning and biodiversity of freshwater ecosystems ranging from temperate ponds and ditches to tropical lakes. Dark, anoxic conditions under thick floating-plant cover leave little opportunity for animal or plant life, and they can have large negative impacts on fisheries and navigation in tropical lakes. Here, we demonstrate that floating-plant dominance can be a self-stabilizing ecosystem state, which may explain its notorious persistence in many situations. Our results, based on experiments, field data, and models, represent evidence for alternative domains of attraction in ecosystems. An implication of our findings is that nutrient enrichment reduces the resilience of freshwater systems against a shift to floating-plant dominance. On the other hand, our results also suggest that a single drastic harvest of floating plants can induce a permanent shift to an alternative state dominated by rooted, submerged growth forms. PMID:12634429

  14. Finite Element Analysis of the Floating Head Structure in Air Compressor Cooling Devices%空气压缩机用冷却装置浮动头结构有限元分析

    Institute of Scientific and Technical Information of China (English)

    王坤; 陈恩; 郭建; 魏纪君; 崔哲

    2015-01-01

    Air compressors produce air of high temperature and high pressure while working,so heat of the air should be taken away by cooling devices between stages.The floating head, which bears severe laod, is the key part of the cooling devices. This paper, based on the ANSYS environment,carries out the dynamic analysis of the float head force condition in the highest working pressure.This paper provides a guarantee for the safe and reliable operation of the floating head and sug-gests the solution during the design and manufacture process of the floating head in order to avoid its strength failure.%空气压缩机工作产生高温高压空气,压缩空气的热量由级间冷却装置带走。浮动头是空气压缩机用冷却装置的关键零件,是承受载荷较为严酷的零件。本文借助ANSYS有限元仿真软件,对最高压力状态下浮动头的受力情况进行分析,为浮动头安全可靠地工作提供保证,并为避免浮动头强度失效从制造加工过程提出解决方案。

  15. Multiprocessing system for performing floating point arithmetic operations

    Energy Technology Data Exchange (ETDEWEB)

    Nguyenphu, M.; Thatcher, L.E.

    1990-10-02

    This patent describes a data processing system. It comprises: a fixed point arithmetic processor means for performing fixed point arithmetic operations and including control means for decoding a floating point arithmetic instruction specifying a floating point arithmetic operation, and an addressing means for computing addresses for floating point data for the floating point operation from a memory means. The memory means for storing data and including means for receiving the addresses from the fixed point arithmetic processor means and providing the floating point data to a floating point arithmetic processor means; and the floating point arithmetic processor means for performing floating point arithmetic operations and including control means for decoding the floating point instruction and performing the specified floating point arithmetic operation upon the floating point data from the memory means.

  16. Investigation of the novel 4Hsbnd SiC trench MOSFET with non-uniform doping floating islands

    Science.gov (United States)

    Song, Qingwen; Tang, Xiaoyan; Tian, Ruiyan; Zhang, Yimeng; Guo, Tao; Tang, Guannan; Yang, Shuai; Yuan, Hao; He, Yanjing

    2016-11-01

    In this paper, a novel 4Hsbnd SiC trench metal-oxide-semiconductor field-effect transistor (MOSFET) with non-uniform doping floating islands is proposed, using a Gaussian doping profile in the floating islands. The feature of the non-uniform doping floating island is that the doping concentration of upper part is higher than the lower part. The electric field between the floating island and drift region can be reduced by the decrease in the doping concentration of the lower part. At the same time, the high doping concentration for the upper part of the floating island is utilized, so that gate oxide layer at the sharp corner of the trench gate bottom cannot be broken down in advance. The simulation results indicate that the breakdown voltage of the novel structure can increase by 48%, compared with the structure with the uniform doping (6 × 1017 cm-3) floating island. Furthermore, the switching and gate charge characteristics of the UMOSFETs with uniform and Gaussian doping floating islands have been simulated using two simple switching circuits. The results indicate that changing the doping concentration of the floating islands has no negative effect on the switching characteristics.

  17. 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.

  18. Capillary floating and the billiard ball problem

    CERN Document Server

    Gutkin, Eugene

    2010-01-01

    We establish a connection between capillary floating in neutral equilibrium and the billiard ball problem. This allows us to reduce the question of floating in neutral equilibrium at any orientation with a prescribed contact angle for infinite homogeneous cylinders to a question about billiard caustics for their orthogonal cross-sections. We solve the billiard problem. As an application, we characterize the possible contact angles and exhibit an infinite family of real analytic non-round cylinders that float in neutral equilibrium at any orientation with constant contact angles.

  19. Floating-point standards: Theory and practice

    Energy Technology Data Exchange (ETDEWEB)

    Cody, W.J.

    1987-01-01

    ANSI/IEEE Std 754-1985, the IEEE Standard for Binary Floating-Point Arithmetic, has now been joined by IEEE Std 854-1987, A Radix- Independent Standard for Floating-Point Arithmetic. These standards specify floating-point arithmetic systems that are intended to simplify the preparation of high-quality numerical software. The success of these standards hinges on how well they are implemented and how well they are supported by enhancements to algebraic languages. This paper briefly outlines the arithmetic systems specified by the standards, and discusses some existing implementations. 16 refs., 1 tab.

  20. Floating point arithmetic in future supercomputers

    Science.gov (United States)

    Bailey, David H.; Barton, John T.; Simon, Horst D.; Fouts, Martin J.

    1989-01-01

    Considerations in the floating-point design of a supercomputer are discussed. Particular attention is given to word size, hardware support for extended precision, format, and accuracy characteristics. These issues are discussed from the perspective of the Numerical Aerodynamic Simulation Systems Division at NASA Ames. The features believed to be most important for a future supercomputer floating-point design include: (1) a 64-bit IEEE floating-point format with 11 exponent bits, 52 mantissa bits, and one sign bit and (2) hardware support for reasonably fast double-precision arithmetic.

  1. New CFOA-based floating immittance emulators

    Science.gov (United States)

    Taher Abuelma'atti, Muhammad; Dhar, Sagar Kumar

    2016-12-01

    This paper presents four new topologies for emulating floating immittance functions. Each circuit uses two or three current-feedback operational-amplifiers (CFOAs) and three passive elements. The proposed topologies can emulate positive/negative lossless and lossy floating inductances, and positive/negative capacitance, resistance and inductance multipliers in addition to floating frequency-dependent positive and negative resistances. The functionality of the proposed circuits is verified using the Advanced Design System software and the AD844 CFOA. The simulation results are in excellent agreement with the theoretical calculations.

  2. Controlled decoherence of floating flux qubits

    Institute of Scientific and Technical Information of China (English)

    Ji Ying-Hua; Xu Lin

    2010-01-01

    In Born-Markov approximation, this paper calculates the energy relaxation time T1 and the decoherence time T2 of a floating flux qubit by solving the set of Bloch-Redfield equations. It shows that there are two main factors influencing the floating flux qubits: coupling capacitor in the circuit and the environment resistor. It also discusses how to improvethe quantum coherence time of a qubit. Through shunt connecting/series connecting inductive elements, an inductive environment resistor is obtained and further the reactance component of the environment resistor is improved, which is beneficial to the enhancement of decoherence time of floating flux qubits.

  3. 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)

  4. The floating city as an ecosystem

    NARCIS (Netherlands)

    Van Uffelen, C., Rentmeester, S.

    2015-01-01

    Floating construction: several municipalities in the Netherlands are working with it on a small scale. TU Delft alumnus Rutger de Graaf of the YesDelft company DeltaSync would like to speed things up with his Blue Revolution.

  5. Physical model tests for floating wind turbines

    DEFF Research Database (Denmark)

    Bredmose, Henrik; Mikkelsen, Robert Flemming; Borg, Michael

    Floating offshore wind turbines are relevant at sites where the depth is too large for the installation of a bottom fixed substructure. While 3200 bottom fixed offshore turbines has been installed in Europe (EWEA 2016), only a handful of floating wind turbines exist worldwide and it is still...... an open question which floater concept is the most economically feasible. The design of the floaters for the floating turbines relies heavily on numerical modelling. While several coupled models exist, data sets for their validation are scarce. Validation, however, is important since the turbine behaviour...... is complex due to the combined actions of aero- and hydrodynamic loads, mooring loads and blade pitch control. The present talk outlines two recent test campaigns with a floating wind turbine in waves and wind. Two floater were tested, a compact TLP floater designed at DTU (Bredmose et al 2015, Pegalajar...

  6. Capillary floating and the billiard ball problem

    OpenAIRE

    Gutkin, Eugene

    2010-01-01

    We establish a connection between capillary floating in neutral equilibrium and the billiard ball problem. This allows us to reduce the question of floating in neutral equilibrium at any orientation with a prescribed contact angle for infinite homogeneous cylinders to a question about billiard caustics for their orthogonal cross-sections. We solve the billiard problem. As an application, we characterize the possible contact angles and exhibit an infinite family of real analytic non-round cyli...

  7. Genetic Algorithms, Floating Point Numbers and Applications

    Science.gov (United States)

    Hardy, Yorick; Steeb, Willi-Hans; Stoop, Ruedi

    The core in most genetic algorithms is the bitwise manipulations of bit strings. We show that one can directly manipulate the bits in floating point numbers. This means the main bitwise operations in genetic algorithm mutations and crossings are directly done inside the floating point number. Thus the interval under consideration does not need to be known in advance. For applications, we consider the roots of polynomials and finding solutions of linear equations.

  8. Verified Compilation of Floating-Point Computations

    OpenAIRE

    Boldo, Sylvie; Jourdan, Jacques-Henri; Leroy, Xavier; Melquiond, Guillaume

    2015-01-01

    International audience; Floating-point arithmetic is known to be tricky: roundings, formats, exceptional values. The IEEE-754 standard was a push towards straightening the field and made formal reasoning about floating-point computations easier and flourishing. Unfortunately, this is not sufficient to guarantee the final result of a program, as several other actors are involved: programming language, compiler, architecture. The CompCert formally-verified compiler provides a solution to this p...

  9. 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.

  10. 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.

  11. 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).

  12. 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.

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

    DEFF Research Database (Denmark)

    Christiansen, Søren; Bak, Thomas; Knudsen, Torben

    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......, 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...

  14. 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.

  15. Dynamically Reconfigurable Processor for Floating Point Arithmetic

    Directory of Open Access Journals (Sweden)

    S. Anbumani,

    2014-01-01

    Full Text Available Recently, development of embedded processors is toward miniaturization and energy saving for ecology. On the other hand, high performance arithmetic circuits are required in a lot of application in science and technology. Dynamically reconfigurable processors have been developed to meet these requests. They can change circuit configuration according to instructions in program instantly during operations.This paper describes, a dynamically reconfigurable circuit for floating-point arithmetic is proposed. The arithmetic circuit consists of two single precision floating-point arithmetic circuits. It performs double precision floating-point arithmetic by reconfiguration. Dynamic reconfiguration changes circuit construction at one clock cycle during operation without stopping circuits. It enables reconfiguration of circuits in a few nano seconds. The proposed circuit is reconfigured in two modes. In first mode it performs one double precision floating-point arithmetic or else the circuit will perform two parallel operations of single precision floating-point arithmetic. The new system design reduces implementation area by reconfiguring common parts of each operation. It also increases the processing speed with a very little number of clocks.

  16. Underwater Shock Response Analysis of a Floating Vessel

    Directory of Open Access Journals (Sweden)

    J.E. van Aanhold

    1998-01-01

    Full Text Available The response of a surface vessel to underwater shock has been calculated using an explicit finite element analysis. The analysis model is two-dimensional and contains the floating steel structure, a large surrounding water volume and the free surface. The underwater shock is applied in the form of a plane shock wave and cavitation is considered in the analysis. Advanced computer graphics, in particular video animations, provide a powerful and indispensable means for the presentation and evaluation of the analysis results.

  17. Economic Floating Waste Detectionfor Surface Cleaning Robots

    Directory of Open Access Journals (Sweden)

    Sumroengrit Jakkrit

    2017-01-01

    Full Text Available Removing waste out of water surface is a routine task and can be operated by using autonomous surface cleaning robots. This paper presents amethodoflaser-based floating waste detection for surface robot guidance when waste positions are unknown beforehand. Basing on concept of refraction and reflection of laser ray, the proposed laser-based technique is proven to be applicable on floating waste detection. The economic waste detector is constructed and mounted on the robot. Five DOF equations of motion are formulated for calculation of waste position incorporating distance measured by the laser and also the robot motion caused by external wind force as well as water surface tension. Experiments were conducted on a pond with calm water and results show that the presented economic waste detection successfully identify and locate position of plastic bottles floating on water surface within the range of 5 meters.

  18. 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...

  19. Improvements in floating point addition/subtraction operations

    Energy Technology Data Exchange (ETDEWEB)

    Farmwald, P.M.

    1984-02-24

    Apparatus is described for decreasing the latency time associated with floating point addition and subtraction in a computer, using a novel bifurcated, pre-normalization/post-normalization approach that distinguishes between differences of floating point exponents.

  20. Floating Inductance and FDNR Using Positive Polarity Current Conveyors

    Directory of Open Access Journals (Sweden)

    K. Pal

    2004-01-01

    Full Text Available A generalized circuit based on five positive polarity second-generation current conveyors is introduced. The circuit simulates a floating inductance, capacitor floatation circuit and floating fdnr. All these circuits use grounded capacitors.

  1. Body-contact self-bias effect in partially depleted SOI-CMOS and alternatives to suppress floating body effect

    Institute of Scientific and Technical Information of China (English)

    Zhou Jianhua; Gao Minghui; S.K.Pang; Zou Shichang

    2011-01-01

    As SOI-CMOS technology nodes reach the tens of nanometer regime, body-contacts become more and more ineffective to suppress the floating body effect In this paper self-bias effect as the cause for this failure is analyzed and discussed in depth with respect to different structures and conditions Other alterative approaches to suppressing the floating body effect are also introduced and discussed.

  2. 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...... quantization noise and saturation distortion into account and concludes that it is preferred to use small blocks and a (new) modified BFP format applying fractional exponents. Data from the EMISAR radar system are applied to illustrate the merits of the different schemes....

  3. 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....

  4. 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

  5. 14 CFR 29.757 - Hull and auxiliary float strength.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hull and auxiliary float strength. 29.757 Section 29.757 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... § 29.757 Hull and auxiliary float strength. The hull, and auxiliary floats if used, must withstand...

  6. The Wave Dragon: 3D overtopping tests on a floating model

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, Luca; Frigaard, Peter

    1999-05-01

    In order to investigate the overtopping likely to occur in the Wave Dragon (WD), some tests were carried out measuring the total overtopping volumes on a floating 1:50 model for 5 selected wave conditions. The model set-up and the tests are first described. The aim of the tests is to measure all the water overtopping the crest freeboard and, if possible, to obtain some elements to enhance the WD efficiency. A typical exponential equation describing overtopping has been fitted to the data. Tests results are then given and compared to previous tests performed in a 2D non-floating model of the structure. (au)

  7. Study on“Floating Fiber”Improvement,Structure and Property of GFRPP Composites%GFRPP复合材料“浮纤”改善及结构与性能研究*

    Institute of Scientific and Technical Information of China (English)

    潘燕; 李又兵; 史文; 盛旭敏; 王恒兵; 李敬媛

    2013-01-01

    以改善玻纤增强聚丙烯(GFRPP)复合材料注射成型“浮纤”现象为研究目标,加入不同用量的石蜡对GFRPP复合材料进行改性,考察了石蜡对GFRPP复合材料表面形貌、流动性能、力学性能和热力学性能的影响。结果表明,加入石蜡有利于改善GFRPP复合材料的“浮纤”现象,加入超过10份石蜡后,复合材料注塑制品表面基本没有玻纤外露现象。随着石蜡用量的增加,复合材料的流动性能显著提高,力学性能有所下降,结晶温度降低。%In order to improve the“floating fiber”phenomenon of glass fiber reinforced polypropylene(GFRPP) composites by injection molding,GFRPP was blended with different proportions of paraffin wax.The effects of paraffin wax on the surface morphology,flow performance,mechanical properties and thermodynamic performance of GFRPP were investigated.The results show that the“floating fiber”phenomenon of GFRPP is improved by adding paraffin wax,when adding more than 10 phr paraffin wax,the surface of injection molding products has no glass fiber exposure phenomenon.With the increase of paraffin wax content, the flow performance of GFRPP/paraffin wax improved significantly ,while the mechanical properties and crystallization temperature decreased.

  8. 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.

  9. 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.

  10. 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 large size turbines....

  11. Floating Breakwater Prototype Test Program: Seattle, Washington.

    Science.gov (United States)

    1986-03-01

    foam weight increased 250 percent because of the absorption of water. This absorption, combined with underfilling of tires during the original...A 2 the float was done in three lifts of about 1 ft each. Handheld electric vibrators were used to reduce the possibility of voids . After the sides

  12. 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...

  13. PLM floating-point interface program

    Energy Technology Data Exchange (ETDEWEB)

    Paoni, C.; Maples, M.

    1976-03-03

    A major failing of Intel's PLM language is its inability to handle scientific notation (floating-point) calculations. An interface program that allows PLM to perform such calculations is described. A comparison of this modified PLM with an assembly language program has shown PLM's effectiveness in reducing the cost of a project. (auth)

  14. 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 .

  15. 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...

  16. 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

  17. FloatingEscherichia coli by Expressing Cyanobacterial Gas Vesicle Genes

    Institute of Scientific and Technical Information of China (English)

    WANG Tianhe; PENG Yong; YANG Zhongzhou; LI Lian; BAO Yingying; XU Haowen; ZHANG Xiaohua; SUI Zhenghong; YANG Guanpin; WANG Xianghong; KANG Li; LI Jiaheng; WU Wenjie; ZHANG Peiran; GONG Minghao; LAI Weihong; ZHANG Chunyan; CHANG Lei

    2015-01-01

    Gas vesicles are hollow, air-filled polyprotein structures that provide the buoyancy to cells. They are found in a variety of prokaryotes. In this study, we isolated a partial gas vesicle protein gene cluster containinggvpA andgvpC20ΨfromPlanktothrix rubescens, and inserted it into an expression vector and expressed it inE. coli. The gas vesicle was developed in bacterial cells, which made bacterial cells to float on medium surface. We also amplifiedgvpAandgvpC20Ψseparately and synthesized an artificial operon by fusing these two genes with the standardized gene expression controlling elements ofE. coli. The artificial operon was expressed inE. coli, forming gas vesicles and floating bacteria cells. Our findings verified that the whole set of genes and the overall structure of gas vesicle gene cluster are not necessary for developing gas vesicles in bacteria cells. Two genes,gvpAandgvpC20Ψ, of the gas vesicle gene cluster are sufficient for synthesizing an artificial operon that can develop gas vesicles in bacteria cells. Our findings provided a wide range of applications including easing the harvest of cultured microalgae and bacteria, as well as enriching and remediating aquatic pollutants by constructing gas vesicles in their cells.

  18. Floating Escherichia coli by expressing cyanobacterial gas vesicle genes

    Science.gov (United States)

    Wang, Tianhe; Kang, Li; Li, Jiaheng; Wu, Wenjie; Zhang, Peiran; Gong, Minghao; Lai, Weihong; Zhang, Chunyan; Chang, Lei; Peng, Yong; Yang, Zhongzhou; Li, Lian; Bao, Yingying; Xu, Haowen; Zhang, Xiaohua; Sui, Zhenghong; Yang, Guanpin; Wang, Xianghong

    2015-02-01

    Gas vesicles are hollow, air-filled polyprotein structures that provide the buoyancy to cells. They are found in a variety of prokaryotes. In this study, we isolated a partial gas vesicle protein gene cluster containing gvpA and gvpC20Ψ from Planktothrix rubescens, and inserted it into an expression vector and expressed it in E. coli. The gas vesicle was developed in bacterial cells, which made bacterial cells to float on medium surface. We also amplified gvpA and gvpC20Ψ separately and synthesized an artificial operon by fusing these two genes with the standardized gene expression controlling elements of E. coli. The artificial operon was expressed in E. coli, forming gas vesicles and floating bacteria cells. Our findings verified that the whole set of genes and the overall structure of gas vesicle gene cluster are not necessary for developing gas vesicles in bacteria cells. Two genes, gvpA and gvpC20Ψ, of the gas vesicle gene cluster are sufficient for synthesizing an artificial operon that can develop gas vesicles in bacteria cells. Our findings provided a wide range of applications including easing the harvest of cultured microalgae and bacteria, as well as enriching and remediating aquatic pollutants by constructing gas vesicles in their cells.

  19. Assessment of Fatigue Strength of An Offshore Floating Production and Storage Unit

    Institute of Scientific and Technical Information of China (English)

    刘建成; 顾永宁

    2002-01-01

    The procedure of assessment of structural fatigue strength of an offshore floating production and storage and offloadingunit(FPSO) in this paper. The emphasis is placed on the long-term prediction of wave induced loading, the refined finite el-ement model for hot spot stress calculation, the combination of stress components, and fatigue damage assessment based onS-N curve.

  20. 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.

  1. 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

    -aft due to the low natural frequency of the floating structure. We suggest a control loop extension of the onshore controller which stabilizes the system and reduces the wave disturbance. The result is improved performance in power fluctuations, blade pitch activity, and platform oscillations...

  2. Numerical Simulation and Experiment on Material Flow Regulation During Superplastic Forming Process of Box-Shaped Part%盒形件超塑成形过程中材料流动规律的数值模拟与实验

    Institute of Scientific and Technical Information of China (English)

    段奇锐; 原晓明

    2012-01-01

    利用有限元软件MSC.Marc2010对钛合金盒形件超塑成形过程进行了有限元模拟,控制目标应变速率,得到优化的压力-时间曲线,并据此进行实验研究,沿实验曲线分别加裁至6个不同的标定压力值(分别为0.5,1.0,1.5,2.0,2.3和2.5 MPa)得到成形过程中的零件.测量6个实验零件的外形轮廓和厚度,并分剐与相对应的模拟结果进行对比,验证实验与模拟的一致性,并分析整个成形过程中的材料流动规律,得出在自由胀形、底部贴模、充填圆角3阶段盒形件不同区域的应力、应变和变薄率分布,为复杂零件的起塑成形工艺的制定奠定了一定的理论基础.%The superplastic forming process of the box-shaped part is simulated by using finite element software MSC. Marc2010 to optimize the curve of pressure-time under the control of the target strain rate. The fitted curve used in the experiment is based on the simulated pressure-time (p-t) curve. The six parts are obtained along the same optimal experiment p-t curve at six selected pressure respectively (0- 5, 1.0, 1-5, 2. 0, 2. 3 and 2. 5 MPa). By measuring the outline and thickness of the six parts, the experimental result is compared with the numerical simulation result to verify if they agree with each other, and the material flow regulation can be analyzed. The distribution results of stress, strain and reduction rate of the three periods of free bulging, closing up to the cavity and corner fiuing are obtained, which lays the theoretical foundation for the superplastic forming process design of complex parts.

  3. Flow-induced oscillations of a floating moored cylinder

    Science.gov (United States)

    Carlson, Daniel; Modarres-Sadeghi, Yahya

    2016-11-01

    An experimental study of flow-induced oscillations of a floating model spar buoy was conducted. The model spar consisted of a floating uniform cylinder moored in a water tunnel test section, and free to oscillate about its mooring attachment point near the center of mass. For the bare cylinder, counter-clockwise (CCW) figure-eight trajectories approaching A* =1 in amplitude were observed at the lower part of the spar for a reduced velocity range of U* =4-11, while its upper part experienced clockwise (CW) orbits. It was hypothesized that the portion of the spar undergoing CCW figure eights is the portion within which the flow excites the structure. By adding helical strakes to the portion of the cylinder with CCW figure eights, the response amplitude was significantly reduced, while adding strakes to portions with clockwise orbital motion had a minimal influence on the amplitude of response. This work is partially supported by the NSF-sponsored IGERT: Offshore Wind Energy Engineering, Environmental Science, and Policy (Grant Number 1068864).

  4. Functionalization of Carbon Nanofibres Obtained by Floating Catalyst Method

    Directory of Open Access Journals (Sweden)

    Adolfo Fernández

    2015-01-01

    Full Text Available The excellent physicochemical and electrical properties of carbon nanofibres (CNF combined with the possibility of being produced at industrial scale at reasonable costs have promoted the interest in their use in very diverse areas. However, there are still some drawbacks that must be solved in order to optimize their set of properties such as the presence of impurities or the imperfections in the crystalline structure. In this work, different modification treatments of CNFs produced by the floating catalyst method have been studied. Three types of modification processes have been explored that can be grouped as mechanical, thermal, and chemical functionalization processes. Mechanical processing has allowed solving the agglomeration problem related to CNFs produced by floating catalyst method and the resulting modified product ensures the secure handling of carbon nanofibres. Thermal and chemical treatments lead to purer and more crystalline products by removing catalyst impurities and amorphous carbon. Functionalization processes explored in this work open the possibility of customized posttreatment of carbon nanofibres according to the desired requirements.

  5. System and method for floating-substrate passive voltage contrast

    Science.gov (United States)

    Jenkins, Mark W.; Cole, Jr., Edward I.; Tangyunyong, Paiboon; Soden, Jerry M.; Walraven, Jeremy A.; Pimentel, Alejandro A.

    2009-04-28

    A passive voltage contrast (PVC) system and method are disclosed for analyzing ICs to locate defects and failure mechanisms. During analysis a device side of a semiconductor die containing the IC is maintained in an electrically-floating condition without any ground electrical connection while a charged particle beam is scanned over the device side. Secondary particle emission from the device side of the IC is detected to form an image of device features, including electrical vias connected to transistor gates or to other structures in the IC. A difference in image contrast allows the defects or failure mechanisms be pinpointed. Varying the scan rate can, in some instances, produce an image reversal to facilitate precisely locating the defects or failure mechanisms in the IC. The system and method are useful for failure analysis of ICs formed on substrates (e.g. bulk semiconductor substrates and SOI substrates) and other types of structures.

  6. Lightning Protection of Floating Roof Tanks

    Directory of Open Access Journals (Sweden)

    Adekitan,

    2013-10-01

    Full Text Available Prior to export, processed crude oil is stored in Floating Roof Tanks (FRT to further allow any trapped gas within the crude oil to escape, as this stabilises the crude oil. In the oil and gas industry, FRT’s are vital in the processing of crude oil to the acceptable export specification.In the tropics and other lightning prone regions, lightning induced floating roof tank fire constitutes a major threat to crude oil production. Among others, a single lightning incident could result in the loss of life, product and production time, avoidable incident review time, damaged equipment, wasted repair cost, bad publicity and loss of income.This paper therefore, is aimed at providing an effective solution to the menace of lightning induced tank fire by focussing on the starting process of the lightning induced fire and proposing alternative concepts for breaking the fire triangle before fire ensues

  7. Floating behavior of hydrophobic glass spheres.

    Science.gov (United States)

    Liu, Xinjie; Wang, Xiaolong; Liang, Yongmin; Zhou, Feng

    2009-08-15

    When a hydrophobic solid sphere is floating on water or salt solutions with different concentrations, it is at equilibrium under the impact of gravity, buoyancy force, and curvature force, the component of surface tension in the vertical direction. We have changed the diameters of the spheres and the concentrations of the two selected salts, NaCl and NaNO(3), to study the floating behaviors of these spheres and the contributions of surface tension and buoyancy force to their floatation. Generally speaking, the surface tension plays a more important role than the buoyancy force when the gravity is small, but the buoyancy force plays an identical or a more important role when the spheres are big enough. The wettability of the spheres significantly influences the height below the contact perimeter especially in salt solutions. The theoretical calculation meniscus slope angles at the sphere three-phase contact line are in agreement with experimental results.

  8. 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.

  9. Arithmetic Operations Beyond Floating Point Number Precision

    CERN Document Server

    Wang, Chih-Yueh; Chen, Hong-Yu; Chen, Yung-Ko

    2010-01-01

    In basic computational physics classes, students often raise the question of how to compute a number that exceeds the numerical limit of the machine. While technique of avoiding overflow/underflow has practical application in the electrical and electronics engineering industries, it is not commonly utilized in scientific computing, because scientific notation is adequate in most cases. We present an undergraduate project that deals with such calculations beyond a machine's numerical limit, known as arbitrary precision arithmetic. The assignment asks students to investigate the validity of floating point number precision and the approach of calculating the exact value of a large number, using the basic scientific programming language Fortran. Examples of the successive multiplication of even number and the multiplication and division of two overflowing floats are presented. The application of the scheme to hardware and firmware design which requires the allocation of finite memory, as in a digital signal proce...

  10. A multiple floating point coprocessor architecture

    Energy Technology Data Exchange (ETDEWEB)

    Rauchwerger, L.; Farmwald, M.P. (Center for Supercomputing Research and Development, Univ. of Illinois at Urbana-Champaign, 305 Talbot Lab., Urbana, IL (US))

    1990-06-01

    General purpose microprocessor based computers usually speed their arithmetic processing performance by using a floating point co-processor. Because adding more co-processors represents neither a technological nor a cost problem the authors investigated a system based on a MIPS R2000 (2) and 4 floating point units. In this paper they show a block diagram of such an implementation and how two important scientific operations can be accelerated using a single unmodified data bus. A large percentage of the engineering applications are solved with the help of linear algebra methods like BLAS3 (4) algorithms; it is precisely for these primitives that the proposed architecture brings significant performance gains. The first operation described is a matrix multiplication algorithm, its timing diagram and some results. Next a polynomial evaluation technique is examined. The authors show how to use the same ideas with various other microprocessors.

  11. Optimizing polynomials for floating-point implementation

    CERN Document Server

    De Dinechin, Florent

    2008-01-01

    The floating-point implementation of a function on an interval often reduces to polynomial approximation, the polynomial being typically provided by Remez algorithm. However, the floating-point evaluation of a Remez polynomial sometimes leads to catastrophic cancellations. This happens when some of the polynomial coefficients are very small in magnitude with respects to others. In this case, it is better to force these coefficients to zero, which also reduces the operation count. This technique, classically used for odd or even functions, may be generalized to a much larger class of functions. An algorithm is presented that forces to zero the smaller coefficients of the initial polynomial thanks to a modified Remez algorithm targeting an incomplete monomial basis. One advantage of this technique is that it is purely numerical, the function being used as a numerical black box. This algorithm is implemented within a larger polynomial implementation tool that is demonstrated on a range of examples, resulting in ...

  12. Capillary deposition of advected floating particles

    Science.gov (United States)

    Dressaire, Emilie; Debaisieux, Aymeric; Gregori, Federico

    2016-11-01

    The deposition and aggregation of particles flowing through a confined environment can dramatically hinder the transport of suspensions. Yet, the mechanisms responsible for the deposition of particles in shear flow are not fully understood. Here, we use an experimental model system in which floating particles are advected on the surface of a water channel and deposited on fixed obstacles through attractive capillary effects. By varying the flow rate of the liquid, the wetting properties and size of the particles and obstacles, we can tune the magnitude of the capillary and hydrodynamic forces that determine the probability of deposition and the equilibrium position on the substrate. We show that arrays of obstacles can be designed to efficiently capture the floating particles advected by the flow.

  13. 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.

  14. 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

  15. Ships as future floating farm systems?

    Science.gov (United States)

    Moustafa, Khaled

    2016-09-29

    Environmental and agriculture challenges such as severe drought, desertification, sprawling cities and shrinking arable lands in large regions in the world compel us to think about alternative and sustainable farming systems. Ongoing projects to build floating cities in the sea suggest that building specific ships for farming purposes (as farming ships or farming boats) would also be attainable to introduce new farming surfaces and boost food production worldwide to cope with food insecurity issues.

  16. Floating asphalt blocks of the Dead Sea

    Energy Technology Data Exchange (ETDEWEB)

    Nissenbaum, A. (Weizmann Inst. of Science, Rehovot, Israel); Aizenshtat, Z.; Goldberg, M.

    1980-01-01

    Large blocks of mineral matter free (less than 0.1%) asphalt are occasionally found floating on the surface of the Dead Sea. Chemical, spectroscopic and isotopic data are given for the asphalt. The source of the asphalt is not accurately known, but presumably it represents mobilization of heavy viscous asphaltic masses at depth below the lake bottom into the floor of the lake. It may be released to the surface by earth tremors.

  17. Synthesizing Accurate Floating-Point Formulas

    OpenAIRE

    Ioualalen, Arnault; Martel, Matthieu

    2013-01-01

    International audience; Many critical embedded systems perform floating-point computations yet their accuracy is difficult to assert and strongly depends on how formulas are written in programs. In this article, we focus on the synthesis of accurate formulas mathematically equal to the original formulas occurring in source codes. In general, an expression may be rewritten in many ways. To avoid any combinatorial explosion, we use an intermediate representation, called APEG, enabling us to rep...

  18. Implementation of Floating-point Coprocessor

    OpenAIRE

    Skogstrøm, Kristian

    2005-01-01

    This thesis presents the architecture and implementation of a high-performance floating-point coprocessor for Atmel's new microcontroller. The coprocessor architecture is based on a fused multiply-add pipeline developed in the specialization project, TDT4720. This pipeline has been optimized significantly and extended to support negation of all operands and single-precision input and output. New hardware has been designed for the decode/fetch unit, the register file, the compare/convert pipe...

  19. Termination of floating-point computations

    OpenAIRE

    Serebrenik, Alexander; De Schreye, Danny

    2005-01-01

    Numerical computations form an essential part of almost any real-world program. Traditional approaches to termination of logic programs are restricted to domains isomorphic to (N,>); more recent works study termination of integer computations where the lack of well-foundedness of the integers has to be taken into account. Termination of computations involving floating-point numbers can be counterintuitive because of rounding errors and implementation conventions. We present a novel technique ...

  20. Floating gate transistors as biosensors (Conference Presentation)

    Science.gov (United States)

    Frisbie, C. Daniel

    2016-11-01

    Electrolyte gated transistors (EGTs) are a sub-class of thin film transistors that are extremely promising for biological sensing applications. These devices employ a solid electrolyte as the gate insulator; the very large capacitance of the electrolyte results in low voltage operation and high transconductance or gain. This talk will describe the fabrication of floating gate EGTs and their use as ricin sensors. The critical performance metrics for EGTs compared with other types of TFTs will also be reviewed.

  1. Novel Nanocrystal Floating Gate Memory

    OpenAIRE

    Zhou, Huimei

    2012-01-01

    This work is devoted to investigating the feasibility of engineering nanocrystals and tunnel oxide layer with a novel structure. Several novel devices are demonstrated to improve the performance of the novel nanocrystal memories.A novel TiSi2 nanocrystal memory was demonstrated. TiSi2 nanocrystals were synthesized on SiO2 by annealing Ti covered Si nanocrystals. Compared to the reference Si nanocrystal memory, both experiment and simulation results show that TiSi2 nanocrystal memory exhibits ...

  2. Float processing of high-temperature complex silicate glasses and float baths used for same

    Science.gov (United States)

    Cooper, Reid Franklin (Inventor); Cook, Glen Bennett (Inventor)

    2000-01-01

    A float glass process for production of high melting temperature glasses utilizes a binary metal alloy bath having the combined properties of a low melting point, low reactivity with oxygen, low vapor pressure, and minimal reactivity with the silicate glasses being formed. The metal alloy of the float medium is exothermic with a solvent metal that does not readily form an oxide. The vapor pressure of both components in the alloy is low enough to prevent deleterious vapor deposition, and there is minimal chemical and interdiffusive interaction of either component with silicate glasses under the float processing conditions. Alloys having the desired combination of properties include compositions in which gold, silver or copper is the solvent metal and silicon, germanium or tin is the solute, preferably in eutectic or near-eutectic compositions.

  3. 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

  4. When chromatin organisation floats astray: the Srcap gene and Floating-Harbor syndrome.

    Science.gov (United States)

    Messina, Giovanni; Atterrato, Maria Teresa; Dimitri, Patrizio

    2016-12-01

    Floating-Harbor syndrome (FHS) is a rare human disease characterised by delayed bone mineralisation and growth deficiency, often associated with mental retardation and skeletal and craniofacial abnormalities. FHS was first described at Boston's Floating Hospital 42 years ago, but the causative gene, called Srcap, was identified only recently. Truncated SRCAP protein variants have been implicated in the mechanism of FHS, but the molecular bases underlying the disease must still be elucidated and investigating the molecular defects leading to the onset of FHS remains a challenge. Here we comprehensively review recent work and provide alterative hypotheses to explain how the Srcap truncating mutations lead to the onset of FHS.

  5. Trident: An FPGA Compiler Framework for Floating-Point Algorithms.

    Energy Technology Data Exchange (ETDEWEB)

    Tripp J. L. (Justin L.); Peterson, K. D. (Kristopher D.); Poznanovic, J. D. (Jeffrey Daniel); Ahrens, C. M. (Christine Marie); Gokhale, M. (Maya)

    2005-01-01

    Trident is a compiler for floating point algorithms written in C, producing circuits in reconfigurable logic that exploit the parallelism available in the input description. Trident automatically extracts parallelism and pipelines loop bodies using conventional compiler optimizations and scheduling techniques. Trident also provides an open framework for experimentation, analysis, and optimization of floating point algorithms on FPGAs and the flexibility to easily integrate custom floating point libraries.

  6. Implementing decimal floating-point arithmetic through binary: some suggestions

    OpenAIRE

    Brisebarre, Nicolas; Ercegovac, Milos; Louvet, Nicolas; Martin-Dorel, Erik; Muller, Jean-Michel; Panhaleux, Adrien

    2010-01-01

    International audience; We propose several algorithms and provide some related results that make it possible to implement decimal floating-point arithmetic on a processor that does not have decimal operators, using the available binary floating-point functions. In this preliminary study, we focus on round-to-nearest mode only. We show that several functions in decimal32 and decimal64 arithmetic can be implemented using binary64 and binary128 floating-point arithmetic, respectively. Specifical...

  7. 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) .

  8. Statistical analysis of the metrological properties of float glass

    Science.gov (United States)

    Yates, Brian W.; Duffy, Alan M.

    2008-08-01

    The radius of curvature, slope error, surface roughness and associated height distribution and power spectral density of uncoated commercial float glass samples have been measured in our Canadian Light Source Optical Metrology Facility, using our Micromap-570 surface profiler and long trace profilometer. The statistical differences in these parameters have been investigated between the tin and air sides of float glass. The effect of soaking the float glass in sulfuric acid to try to dissolve the tin contamination has also been investigated, and untreated and post-treatment surface roughness measurements compared. We report the results of our studies on these float glass samples.

  9. FORMULATION AND EVALUATION OF FLOATING TABLETS OF NORFLOXACIN

    Directory of Open Access Journals (Sweden)

    Ms. Jyoti Rathore

    2015-01-01

    Full Text Available The oral route is considered as the most promising route of drug delivery. Several approaches have been attempted in the preparation of gastro-retentive drug delivery systems. These include floating systems, swell able and expandable systems, high density systems, bioadhesive systems, altered shape systems, gel forming solution or suspension systems and sachet systems. Various approaches have been followed to encourage gastric retention of an oral dosage form. Floating systems have low bul density so that they can float on the gastric juice in the stomach. The problem arises when the stomach is completely emptied of gastric fluid. In such a situation, there is nothing to float on.

  10. 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.

  11. Floating-Point Numbers with Error Estimates (revised)

    CERN Document Server

    Masotti, Glauco

    2012-01-01

    The study addresses the problem of precision in floating-point (FP) computations. A method for estimating the errors which affect intermediate and final results is proposed and a summary of many software simulations is discussed. The basic idea consists of representing FP numbers by means of a data structure collecting value and estimated error information. Under certain constraints, the estimate of the absolute error is accurate and has a compact statistical distribution. By monitoring the estimated relative error during a computation (an ad-hoc definition of relative error has been used), the validity of results can be ensured. The error estimate enables the implementation of robust algorithms, and the detection of ill-conditioned problems. A dynamic extension of number precision, under the control of error estimates, is advocated, in order to compute results within given error bounds. A reduced time penalty could be achieved by a specialized FP processor. The realization of a hardwired processor incorporat...

  12. 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.

  13. Floating of the lobes of mosquito (Aedes togoi) larva for respiration

    Science.gov (United States)

    Lee, Seung Chul; Kim, Jun Ho; Lee, Sang Joon

    2017-01-01

    Mosquito (Aedes togoi) larva has to float its siphon on the water surface to breathe air. To elucidate the floating mechanism of the siphon, morphological structures, especially the flap-like lobes and spiracle of the siphon, were observed. Wettability and dynamic behavior of the lobes on the water surface were also experimentally examined. The lobes formed a hollow cone shape under water and expanded on the water surface. The spiracle was located at the base of the cone. The lobes exhibited hydrophobic wettability. During floating process, the lobes were spread into a triangular shape in apical view, and the spiracle was exposed to air. When they were submerged in water, the lobes were folded into a cone shape to seal the spiracle and protect it from water penetration. These dynamic processes occurred at the water surface. In this study, the floating mechanism of the lobes for respiration was described based on the cross-sectional morphology of the lobes with the pressure induced by surface tension and the hydrostatic pressure proportional to depth. This study would be helpful in elucidating the behavior of mosquito larvae near the water surface and may facilitate the formulation of methods to control mosquito larvae. PMID:28216635

  14. Floating of the lobes of mosquito (Aedes togoi) larva for respiration.

    Science.gov (United States)

    Lee, Seung Chul; Kim, Jun Ho; Lee, Sang Joon

    2017-02-20

    Mosquito (Aedes togoi) larva has to float its siphon on the water surface to breathe air. To elucidate the floating mechanism of the siphon, morphological structures, especially the flap-like lobes and spiracle of the siphon, were observed. Wettability and dynamic behavior of the lobes on the water surface were also experimentally examined. The lobes formed a hollow cone shape under water and expanded on the water surface. The spiracle was located at the base of the cone. The lobes exhibited hydrophobic wettability. During floating process, the lobes were spread into a triangular shape in apical view, and the spiracle was exposed to air. When they were submerged in water, the lobes were folded into a cone shape to seal the spiracle and protect it from water penetration. These dynamic processes occurred at the water surface. In this study, the floating mechanism of the lobes for respiration was described based on the cross-sectional morphology of the lobes with the pressure induced by surface tension and the hydrostatic pressure proportional to depth. This study would be helpful in elucidating the behavior of mosquito larvae near the water surface and may facilitate the formulation of methods to control mosquito larvae.

  15. Nonvolatile Transistor Memory with Self-Assembled Semiconducting Polymer Nanodomain Floating Gates.

    Science.gov (United States)

    Wang, Wei; Kim, Kang Lib; Cho, Suk Man; Lee, Ju Han; Park, Cheolmin

    2016-12-14

    Organic field effect transistor based nonvolatile memory (OFET-NVM) with semiconducting nanofloating gates offers additional benefits over OFET-NVMs with conventional metallic floating gates due to the facile controllability of charge storage based on the energetic structure of the floating gate. In particular, an all-in-one tunneling and floating-gate layer in which the semiconducting polymer nanodomains are self-assembled in the dielectric tunneling layer is promising. In this study, we utilize crystals of a p-type semiconducting polymer in which the crystalline lamellae of the polymer are spontaneously developed and embedded in the tunneling matrix as the nanofloating gate. The widths and lengths of the polymer nanodomains are approximately 20 nm and a few hundred nanometers, respectively. An OFET-NVM containing the crystalline nanofloating gates exhibits memory performance with a large memory window of 10 V, programming/erasing switching endurance for over 500 cycles, and a long retention time of 5000 s. Moreover, the device performance is improved by comixing with an n-type semiconductor; thus, the solution-processed p- and n-type double floating gates capable of storing both holes and electrons allow for the multilevel operation of our OFET-NVM. Four highly reliable levels (two bits per cell) of charge trapping and detrapping are achieved using this OFET-NVM by accurately choosing the programming/erasing voltages.

  16. 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.

  17. A numerical modeling for the wave forcing of floating thin plate

    Energy Technology Data Exchange (ETDEWEB)

    Basirat Tabrizi, H. [Amirkabir Univ. of Technology, Mechanical Engineering Dept., Tehran (Iran, Islamic Republic of)]. E-mail: hbasirat@aut.ac.ir, H.Basirat@dal.ca; Kouchaki Motlaq, M. [Islamic Azad Univ., Dept. of Graduate Studies, Arak (Iran, Islamic Republic of)

    2004-07-01

    A finite difference scheme based on central difference, which is applicable to the thin plate floating on intermediate depth water subjected to wave force, is developed. The floating structure analyzed as a plate with unit width and expressed by an elastic bending theory. The fluid flow expressed as an incompressible, inviscid and steady that the potential theory can apply. Here, the water wave elevation assumed the same as the bending displacement structure at the interface. The distribution of the displacement amplitude of structure and the wave amplitude varies in a wavy pattern in the middle part and increases greatly near the edge of plate. The present method verified by comparing quantitatively with the reported experimental and theoretical results of others. (author)

  18. Optimized design of 4H-SiC floating junction power Schottky barrier diodes

    Institute of Scientific and Technical Information of China (English)

    Pu Hongbin; Cao Lin; Chen Zhiming; Ren Jie

    2009-01-01

    SiC floating junction Schottky barrier diodes were simulated with software MEDICI 4.0 and their device structures were optimized based on forward and reverse electrical characteristics.Compared with the conventional power Schottky barrier diode,the device structure is featured by a highly doped drift region and embedded floating junction region,which can ensure high breakdown voltage while keeping lower specific on-state resistance,solved the contradiction between forward voltage drop and breakdown voltage.The simulation results show that with optimized structure parameter,the breakdown voltage Can reach 4 kV and the specific on-resistance is 8.3 mΩ·cm2.

  19. 水生漂浮型喜旱莲子草群落对底栖动物群落的影响%Effects of aquatic floating type Alternanthera philoxeroides community upon zoobenthos community structure

    Institute of Scientific and Technical Information of China (English)

    王魏根; 孟勤

    2014-01-01

    从2011年12月到2012年5月,分别在喜旱莲子草枯萎期、萌发期和繁盛期调查了七渔河阜阳段喜旱莲子草群落覆盖区和未覆盖区底栖动物群落结构。此次调查共采集到底栖动物12种,主要是一些耐污染的种类,包括环节动物、腹足类、甲壳动物和水生昆虫。在喜旱莲子草覆盖区和未覆盖区,底栖动物平均密度分别为312 ind·m -2和280 ind·m -2,平均生物量分别为1.76 g·m -2和0.6 g·m -2。生物多样性指数值在0.92和1.47之间。由于底栖动物各个类群生活习性不同,喜旱莲子草群落对底栖动物各个类群的影响也不相同。%From December 2011 to May 2012, the zoobenthos community in Qiyu River at Fuyang section were investigated at different water areas (covered by Alternanthera philoxeroides community and not) during three life stages of Alternanthera philoxe-roides (withered stage, germinative stage and luxuriant stage). The total of 12 zoobenthos species were discovered which include Annelida, Gastropoda, Crustacea and Arthropoda, and most of the species are resistant to pollution. At the water area covered by Alternanthera philoxeroides community and not, the zoobenthos average density is 312 ind·m - 2 and 280 ind·m - 2 , respectively, and the average biomass is 1. 76 g·m - 2 and 0. 6 g·m - 2 respectively. Shannon-Wiener biodiversity index value ranges from 0. 92 to 1. 47. Because life habits of every zoobenthos group are different, the effects of aquatic floating type Alternanthera philoxeroides com-munity upon every zoobenthos group are different.

  20. 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...

  1. Simple Evaluation of Load-Carrying Capacity of Multi-Span Folding Bridges based on Floating Supports

    Directory of Open Access Journals (Sweden)

    Jan Marszałek

    2014-12-01

    Full Text Available [b]Abstract[/b]. The papers covers simple evaluation of load-carrying capacity of multi-span folding bridges based on floating supports. Combined bridges built in this approach, could be used as a temporary crossing. The methodology of this evaluation is shown graphically on the basis of designed nomograms for two existing bridge structures i.e. MS-54 and DMS-65, mounted on rigid and floating supports. These nomograms facilitate the simple and fast determination of the impact of changing fixed support into floating support with different bridge length spans on the carrying capacity of the bridge. The paper also presents the influence of long-term use (enlarging the mounting backlash in the joints of these structures on the carrying capacity of the bridge.[b]Keywords[/b]: building, folding bridges, nomograms, assembly clearances

  2. 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....

  3. 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.

  4. An integrated circuit floating point accumulator

    Science.gov (United States)

    Goldsmith, T. C.

    1977-01-01

    Goddard Space Flight Center has developed a large scale integrated circuit (type 623) which can perform pulse counting, storage, floating point compression, and serial transmission, using a single monolithic device. Counts of 27 or 19 bits can be converted to transmitted values of 12 or 8 bits respectively. Use of the 623 has resulted in substantial savaings in weight, volume, and dollar resources on at least 11 scientific instruments to be flown on 4 NASA spacecraft. The design, construction, and application of the 623 are described.

  5. Rounding in redundant digit floating point system

    Science.gov (United States)

    Fahmy, Hossam A. H.; Flynn, Michael J.

    2003-12-01

    Redundant representations are used to increase the performance of arithmetic units. If redundancy is eliminated, the bits needed to represent a number may increase or decrease depending on the type of redundancy used. In such a redundant representation, finding the exact location and correct decision for rounding without eliminating the redundancy or loosing its performance gains is difficult. This paper discusses the different issues related to rounding in redundant systems. It also presents a solution that was used to maintain the gains of redundancy in a floating point unit while correctly implementing the IEEE rounding modes.

  6. DESIGN APPLICATION OF THE WATER-DISCHARGING PRESSURE RELIEF TECHNOLOGY ON ANTI-FLOATING OF STRUCTURES IN UNIVERSAL STUDIOS SINGAPORE%建筑排水减压抗浮新技术在新加坡环球影城中的设计应用

    Institute of Scientific and Technical Information of China (English)

    刘波; 刘钟; 张慧东; 许佳; 陈福林

    2011-01-01

    The inflexible response to variation of groundwater level and the adverse impact on building or environment are two main defects of the common design methods on anti-floating of structures.The water-discharging pressure relief technology on anti-floating of structures got effective approaches to dealing with them on the basis of common methods.The new technology aimed at keeping a stable groundwater level and minimizing adverse effect on environment around by dynamic control system of the combination of water-discharging pressure relief system and pressure relief security control system.Refer to the successful application of the new system in the project of Universal Studios Singapore,the new system and its design principle was introduced.The practice showed that the system in Universal Studios Singapore well adapted to the variation of groundwater level in different seasons since which was put into service,and ensured safety of the project.%传统的建筑抗浮设计法面对复杂的工程和水文地质条件时,存在两类矛盾:一是被动适应,不能灵活处理水位变化带来的影响;二是对建筑物及环境产生不利影响。建筑排水减压抗浮新技术是对传统方法的发展和完善,通过排水减压系统和减压安全控制系统动态调节建筑基底地下水位,以保持地下水位的稳定,从而既能主动适应水位的变化,又能将抗浮系统对建筑物及环境的影响最小化。其在新加坡环球影城项目中的设计应用结果表明,该抗浮系统能较好适应不同季节水位的变化,保障了新加坡环球影城的安全。

  7. 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)

  8. 40 CFR 63.1043 - Standards-Separator floating roof.

    Science.gov (United States)

    2010-07-01

    ...) National Emission Standards for Oil-Water Separators and Organic-Water Separators § 63.1043 Standards... controlling air emissions from an oil-water separator or organic-water separator using a floating roof. (b... floating roof shall be equipped with two continuous seals, one above the other, between the wall of...

  9. 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.

  10. Comments on the floating body and the hyperplane conjecture

    CERN Document Server

    Fresen, Daniel

    2011-01-01

    We provide upper and lower bounds on the logarithmic Hausdorff distance between an arbitrary convex body $K\\subset \\mathbb{R}^{d}$\\ and the convex floating body $K_{\\delta}$ inside $K$. We also discuss the hyperplane conjecture (the slicing problem) and provide a reformulation of this famous unsolved mystery in terms of the floating body.

  11. Characterization of Floating Surface Layers of Lipids and Lipopolymers by Surface-Sensitive Scattering

    Science.gov (United States)

    Krüger, Peter; Lösche, Mathias

    Nanotechnology and molecular (bio-)engineering are making ever deepening inroads into everybodys daily life. Physicochemical and biotechnological achievements in the design of physiologically active supramolecular assemblies have brought about the quest for their submolecular-level characterization. We employ surface-sensitive scattering techniques for the investigation of planar lipid membranes - floating monolayers on aqueous surfaces - to correlate structural, functional and dynamic aspects of biomembrane models. This chapter surveys recent work on the submolecular structure of floating phospholipid monolayers - where the advent of third-generation synchrotron X-ray sources has driven the development of realistic, submolecular-scale quasi-chemical models - as well as of more complex systems: cation binding to anionic lipid surfaces; conformational changes of lipopolymers undergoing phase transitions; the conformational organization of phosphatidylinositol and phosphatidylinositides, as examples of physiologically important lipids; and the adsorption of peptides (neuropeptide Y, NPY) or solvents (dimethylsulfoxide, DMSO) onto phospholipid surface layers.

  12. Floating substructure flexibility of large-volume 10MW offshore wind turbine platforms in dynamic calculations

    Science.gov (United States)

    Borg, Michael; Melchior Hansen, Anders; Bredmose, Henrik

    2016-09-01

    Designing floating substructures for the next generation of 10MW and larger wind turbines has introduced new challenges in capturing relevant physical effects in dynamic simulation tools. In achieving technically and economically optimal floating substructures, structural flexibility may increase to the extent that it becomes relevant to include in addition to the standard rigid body substructure modes which are typically described through linear radiation-diffraction theory. This paper describes a method for the inclusion of substructural flexibility in aero-hydro-servo-elastic dynamic simulations for large-volume substructures, including wave-structure interactions, to form the basis of deriving sectional loads and stresses within the substructure. The method is applied to a case study to illustrate the implementation and relevance. It is found that the flexible mode is significantly excited in an extreme event, indicating an increase in predicted substructure internal loads.

  13. Dynamic analysis of a floating body in the fluid by using the smoothed particle hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Chul Woong; Sohn, Jeong Hyun; Lee, Kyung Chang [Pukyong National University, Busan (Korea, Republic of)

    2015-07-15

    This paper describes a method for the prediction of behavior of a floating-type structure using an experiment and numerical analysis according to the various marine conditions. The sloshing simulation is considered to verify the behavior of fluid. The fluid is expressed by a set of particles, the motion of fluid is calculated by using SPH (Smoothed particle hydrodynamics). Numerical results are compared with experiments. A wave tank and linear shaker are used in order to express the sloshing environment. Monaghan boundary force is employed to calculate the interacting force between fluid and boundary. Four wave periods are used to consider the various marine conditions in the fluid-structure interacting simulation. The longitudinal motion of a floating body is compared to each other. As a result, the solution of numerical analysis shows the similar tendency compared to the experiment results.

  14. Evaporation mitigation by floating modular devices

    Science.gov (United States)

    Hassan, M. M.; Peirson, W. L.

    2016-05-01

    Prolonged periods of drought and consequent evaporation from open water bodies in arid parts of Australia continue to be a threat to water availability for agricultural production. Over many parts of Australia, the annual average evaporation exceeds the annual precipitation by more than 5 times. Given its significance, it is surprising that no evaporation mitigation technique has gained widespread adoption to date. High capital and maintenance costs of manufactured products are a significant barrier to implementation. The use of directly recycled clean plastic containers as floating modular devices to mitigate evaporation has been investigated for the first time. A six-month trial at an arid zone site in Australia of this potential cost effective solution has been undertaken. The experiment was performed using clean conventional drinking water bottles as floating modules on the open water surface of 240-L tanks with three varying degrees of covering (nil, 34% and 68%). A systematic reduction in evaporation is demonstrated during the whole study period that is approximately linearly proportional to the covered surface. These results provide a potential foundation for robust evaporation mitigation with the prospect of implementing a cost-optimal design.

  15. 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.

  16. 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...

  17. 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.

  18. 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.

  19. Balloon Pump with Floating Valves for Portable Liquid Delivery

    Directory of Open Access Journals (Sweden)

    Yuya Morimoto

    2016-03-01

    Full Text Available In this paper, we propose a balloon pump with floating valves to control the discharge flow rates of sample solutions. Because the floating valves were made from a photoreactive resin, the shapes of the floating valves could be controlled by employing different exposure patterns without any change in the pump configurations. Owing to the simple preparation process of the pump, we succeeded in changing the discharge flow rates in accordance with the number and length of the floating valves. Because our methods could be used to easily prepare balloon pumps with arbitrary discharge properties, we achieved several microfluidic operations by the integration of the balloon pumps with microfluidic devices. Therefore, we believe that the balloon pump with floating valves will be a useful driving component for portable microfluidic systems.

  20. 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.

  1. The design for the fuzzy PID control of the intelligent following vehicle with gas floating

    Institute of Scientific and Technical Information of China (English)

    He Yi; Song Xiaodong; Chen Ming

    2012-01-01

    The intelligent following vehicle with gas floating has the characteristics of complicated structure and large quality. In this paper ,the author first establish the mathematical mode of the motion system land and then design a controller using the fuzzy PID control method which could realize auto-tuning PID parameters. By the MATLAB simulation analysis, the results show that fuzzy self-tuning PID control can enhance the response speed of system and has a better adaptability.

  2. The western South China Sea currents from measurements by Argo profiling floats during October to December 2007

    Institute of Scientific and Technical Information of China (English)

    周慧; 袁东亮; 李瑞祥; 何蕾

    2010-01-01

    The three dimensional structure of the western boundary current east of the Vietnam coast was determined from measurements by Argo profiling floats which deployed near the east of the Vietnam Coast in October 2007. The trajectories of the Argo floats provided robust evidence that there does exist southward flowing current along the Vietnam coast. The southward current begins at about 15°N, 111°E, flowing along the 1 000 m isobath and extending to 5°N south. The estimated surface and parking depth velocities...

  3. 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.

  4. 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

  5. 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).

  6. Clustering of floating particles in stratified turbulence

    Science.gov (United States)

    Boffetta, Guido; de Lillo, Filippo; Musacchio, Stefano; Sozza, Alessandro

    2016-11-01

    We study the dynamics of small floating particles transported by stratified turbulence in presence of a mean linear density profile as a simple model for the confinement and the accumulation of plankton in the ocean. By means of extensive direct numerical simulations we investigate the statistical distribution of floaters as a function of the two dimensionless parameters of the problem. We find that vertical confinement of particles is mainly ruled by the degree of stratification, with a weak dependency on the particle properties. Conversely, small scale fractal clustering, typical of non-neutral particles in turbulence, depends on the particle relaxation time and is only weakly dependent on the flow stratification. The implications of our findings for the formation of thin phytoplankton layers are discussed.

  7. 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.

  8. Potential of water surface-floating microalgae for biodiesel production: Floating-biomass and lipid productivities.

    Science.gov (United States)

    Muto, Masaki; Nojima, Daisuke; Yue, Liang; Kanehara, Hideyuki; Naruse, Hideaki; Ujiro, Asuka; Yoshino, Tomoko; Matsunaga, Tadashi; Tanaka, Tsuyoshi

    2017-03-01

    Microalgae have been accepted as a promising feedstock for biodiesel production owing to their capability of converting solar energy into lipids through photosynthesis. However, the high capital and operating costs, and high energy consumption, are hampering commercialization of microalgal biodiesel. In this study, the surface-floating microalga, strain AVFF007 (tentatively identified as Botryosphaerella sudetica), which naturally forms a biofilm on surfaces, was characterized for use in biodiesel production. The biofilm could be conveniently harvested from the surface of the water by adsorbing onto a polyethylene film. The lipid productivity of strain AVFF007 was 46.3 mg/L/day, allowing direct comparison to lipid productivities of other microalgal species. The moisture content of the surface-floating biomass was 86.0 ± 1.2%, which was much lower than that of the biomass harvested using centrifugation. These results reveal the potential of this surface-floating microalgal species as a biodiesel producer, employing a novel biomass harvesting and dewatering strategy.

  9. 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

  10. Numerical Solution of Membrane Forces for A Free-Free Floating Plate with Large Deflection

    Institute of Scientific and Technical Information of China (English)

    陈徐均; 崔维成; 宋皓; 汤雪峰

    2003-01-01

    Considering that the thickness of a pontoon-type very large floating structure (VLFS) is very small in comparison with the length and width, VLFS can be modeled as a thin plate. In theory, the displacements and the membrane forces of a plate with large deflection are all the functions of the second-order differentials of the Ariy stress function. With these characteristics considered, the Ariy stress function of a floating free-free plate is calculated by setting the virtual values of three of the corner points. The finite difference method is chosen to solve the problem. When the Ariy stress function of the plate is obtained, the membrane forces can easily be calculated. Comparisons between the forces induced by the membrane forces and by the fluid are considered. It is shown that the membrane forces can not be neglected in many cases.

  11. Systematic model researches on the stability limits of the DVL series of float designs

    Science.gov (United States)

    Sottorf, W.

    1949-01-01

    To determine the trim range in which a seaplane can take off without porpoising, stability tests were made of a Plexiglas model, composed of float, wing, and tailplane, which corresponded to a full-size research airplane. The model and full-size stability limits are in good agreement. After all structural parts pertaining to the air frame were removed gradually, the aerodynamic forces replaced by weight forces, and the moment of inertia and position of the center of gravity changed, no marked change of limits of the stable zone was noticeable. The latter, therefore, is for practical purposes affected only by hydrodynamic phenomena. The stability limits of the DVL family of floats were determined by a systematic investigation independent of any particular sea-plane design, thus a seaplane may be designed to give a run free from porpoising.

  12. 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.

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

    Directory of Open Access Journals (Sweden)

    L. CASELLA

    2010-04-01

    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.

  14. 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.

  15. A non-local method for robustness analysis of floating point programs

    Directory of Open Access Journals (Sweden)

    Ivan Gazeau

    2012-07-01

    Full Text Available Robustness is a standard correctness property which intuitively means that if the input to the program changes less than a fixed small amount then the output changes only slightly. This notion is useful in the analysis of rounding error for floating point programs because it helps to establish bounds on output errors introduced by both measurement errors and by floating point computation. Compositional methods often do not work since key constructs—like the conditional and the while-loop—are not robust. We propose a method for proving the robustness of a while-loop. This method is non-local in the sense that instead of breaking the analysis down to single lines of code, it checks certain global properties of its structure. We show the applicability of our method on two standard algorithms: the CORDIC computation of the cosine and Dijkstra's shortest path algorithm.

  16. A non-local method for robustness analysis of floating point programs

    CERN Document Server

    Gazeau, Ivan; Palamidessi, Catuscia

    2012-01-01

    Robustness is a standard correctness property which intuitively means that if the input to the program changes less than a fixed small amount then the output changes only slightly. This notion is useful in the analysis of rounding error for floating point programs because it helps to establish bounds on output errors introduced by both measurement errors and by floating point computation. Compositional methods often do not work since key constructs---like the conditional and the while-loop---are not robust. We propose a method for proving the robustness of a while-loop. This method is non-local in the sense that instead of breaking the analysis down to single lines of code, it checks certain global properties of its structure. We show the applicability of our method on two standard algorithms: the CORDIC computation of the cosine and Dijkstra's shortest path algorithm.

  17. Extrapolation of extreme response for different mooring line systems of floating wave energy converters

    DEFF Research Database (Denmark)

    Ambühl, Simon; Sterndorff, Martin; Sørensen, John Dalsgaard

    2014-01-01

    Mooring systems for floating wave energy converters (WECs) are a major cost driver. Failure of mooring systems often occurs due to extreme loads. This paper introduces an extrapolation method for extreme response which accounts for the control system of a WEC that controls the loads onto the stru......Mooring systems for floating wave energy converters (WECs) are a major cost driver. Failure of mooring systems often occurs due to extreme loads. This paper introduces an extrapolation method for extreme response which accounts for the control system of a WEC that controls the loads onto...... the structure and the harvested power of the device as well as the fact that extreme loads may occur during operation and not at extreme wave states when the device is in storm protection mode. The extrapolation method is based on shortterm load time series and applied to a case study where up-scaled surge load...

  18. 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.

  19. 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.

  20. Open source high performance floating-point modules.

    Energy Technology Data Exchange (ETDEWEB)

    Underwood, Keith Douglas

    2006-02-01

    Given the logic density of modern FPGAs, it is feasible to use FPGAs for floating-point applications. However, it is important that any floating-point units that are used be highly optimized. This paper introduces an open source library of highly optimized floating-point units for Xilinx FPGAs. The units are fully IEEE compliant and achieve approximately 230 MHz operation frequency for double-precision add and multiply in a Xilinx Virtex-2-Pro FPGA (-7 speed grade). This speed is achieved with a 10 stage adder pipeline and a 12 stage multiplier pipeline. The area requirement is 571 slices for the adder and 905 slices for the multiplier.

  1. Bioinspired oil strider floating at the oil/water interface supported by huge superoleophobic force.

    Science.gov (United States)

    Liu, Xueli; Gao, Jun; Xue, Zhongxin; Chen, Li; Lin, Ling; Jiang, Lei; Wang, Shutao

    2012-06-26

    Oil pollution to aquatic devices, especially to those oil-cleaning devices and equipment-repairing robots during oil spill accidents, has drawn great attention and remains an urgent problem to be resolved. Developing devices that can move freely in an oil/water system without contamination from oil has both scientific and practical importance. In nature, the insect water strider can float on water by utilizing the superhydrophobic supporting force received by its legs. Inspired by this unique floating phenomenon, in this article, we designed a model device named "oil strider" that could float stably at the oil/water interface without contamination by oil. The floating capability of the oil strider originated from the huge underwater superoleophobic supporting force its "legs" received. We prepared the micro/nanohierarchical structured copper-oxide-coated copper wires, acting as the artificial legs of oil strider, by a simple base-corrosion process. The surface structures and hydrophilic chemical components of the coatings on copper wires induced the huge superoleophobic force at the oil/water interface, to support the oil strider from sinking into the oil. Experimental results and theoretical analysis demonstrate that this supporting force is mainly composed of three parts: the buoyancy force, the curvature force, and the deformation force. We anticipate that this artificial oil strider will provide a guide for the design of smart aquatic devices that can move freely in an oil/water system with excellent oil repellent capability, and be helpful in practical situations such as oil handling and oil spill cleanup.

  2. Single layer of Ge quantum dots in HfO2 for floating gate memory capacitors.

    Science.gov (United States)

    Lepadatu, A M; Palade, C; Slav, A; Maraloiu, A V; Lazanu, S; Stoica, T; Logofatu, C; Teodorescu, V S; Ciurea, M L

    2017-04-28

    High performance trilayer memory capacitors with a floating gate of a single layer of Ge quantum dots (QDs) in HfO2 were fabricated using magnetron sputtering followed by rapid thermal annealing (RTA). The layer sequence of the capacitors is gate HfO 2/floating gate of single layer of Ge QDs in HfO 2/tunnel HfO 2/p-Si wafers. Both Ge and HfO2 are nanostructured by RTA at moderate temperatures of 600-700 °C. By nanostructuring at 600 °C, the formation of a single layer of well separated Ge QDs with diameters of 2-3 nm at a density of 4-5 × 10(15) m(-2) is achieved in the floating gate (intermediate layer). The Ge QDs inside the intermediate layer are arranged in a single layer and are separated from each other by HfO2 nanocrystals (NCs) about 8 nm in diameter with a tetragonal/orthorhombic structure. The Ge QDs in the single layer are located at the crossing of the HfO2 NCs boundaries. In the intermediate layer, besides Ge QDs, a part of the Ge atoms is segregated by RTA at the HfO2 NCs boundaries, while another part of the Ge atoms is present inside the HfO2 lattice stabilizing the tetragonal/orthorhombic structure. The fabricated capacitors show a memory window of 3.8 ± 0.5 V and a capacitance-time characteristic with 14% capacitance decay in the first 3000-4000 s followed by a very slow capacitance decrease extrapolated to 50% after 10 years. This high performance is mainly due to the floating gate of a single layer of well separated Ge QDs in HfO2, distanced from the Si substrate by the tunnel oxide layer with a precise thickness.

  3. 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.

  4. 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...

  5. 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...

  6. Floating Cities: ‘we have a dream to realize’

    OpenAIRE

    Boogaard, Floris; Graaf, R.E. de

    2013-01-01

    A fundamental new approach to urban development is needed for the challenges of the 21st century. Floating houses and cities can accommodate future urbanization without sacrificing land and provide a sustainable living.

  7. WindFloat Pacific Project, Final Scientific and Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Banister, Kevin [Principle Power, Inc., Emeryville, CA (United States)

    2017-01-17

    PPI’s WindFloat Pacific project (WFP) was an up to 30 MW floating offshore wind demonstration project proposed off the Coast of Oregon. The project was to be sited approximately 18 miles due west of Coos Bay, in over 1000 ft. of water, and is the first floating offshore wind array proposed in the United States, and the first offshore wind project of any kind proposed off the West Coast. PPI’s WindFloat, a semi-submersible foundation designed for high-capacity (6MW+) offshore wind turbines, is at the heart of the proposed project, and enables access to the world class wind resource at the project site and, equally, to other deep water, high wind resource areas around the country.

  8. Wave transmission prediction of multilayer floating breakwater using neural network

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Patil, S.G.; Hegde, A.V.

    In the present study, an artificial neural network method has been applied for wave transmission prediction of multilayer floating breakwater. Two neural network models are constructed based on the parameters which influence the wave transmission...

  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. Efficient Implementation of Decimal Floating Point Adder in FPGA

    Directory of Open Access Journals (Sweden)

    Yang Huijing

    2013-10-01

    Full Text Available Decimal floating Point adder is one of the most frequent operations used by many financial, business and user-oriented applications but current implementations in FPGAs are very inefficient in terms of both area and latency when compared to binary floating point adder. This paper has shown an efficient implementation of a new parallel decimal floating point module on a reconfigurable platform, which is both area as well as performance optimal. The decimal floating-point Adder was further pipelined into five stages to increase the maximum frequency of operation. The synthesis results for a Stratix IV device indicate that our implementations have 25.1% reduction of the latency and 1.1% reduction of area compared to an existing alter-core adder design, presenting area and delay figures close to those of optimal binary adder trees.  

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. 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...

  13. 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...

  14. 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.

  15. Floating tidal power station. Schwimmkoerper-Gezeiten-Kraftwerk

    Energy Technology Data Exchange (ETDEWEB)

    Muenzner, H.J.

    1987-03-19

    This is a floating tidal power station, characterized by the fact that water stores are lifted by the tide by float lifts in the form of docks; on the flood tide they are supported mechanically at the height reached by support members or hydraulically, until after several tides a favourable and economically justifiable height for the technical efficiency of water turbines is reached by the first water store. The stored water is then released through water turbines to obtain energy. This emptied water store is then lowered to the initial position with the support members with the aid of emptied float lifts built like ship's lifting equipment (which only require a slight movement of a weight for lifting and lowering). The filling and lifting is then repeated. During this regeneration, the energy is obtained from the next water store. A whole floating tidal power station consists of as many water stores as are required for uninterrupted continuous operation.

  16. Dynamic Response Analysis of a Floating Mooring System

    Institute of Scientific and Technical Information of China (English)

    LE Conghuan; DING Hongyan; ZHANG Puyang

    2014-01-01

    An innovative floating mooring system with two or more independent floating mooring platforms in the middle and one rigid platform on each side is proposed for improving efficiency and safety in shallow water. For this new system, most of collision energy is absorbed through the displacement of floating platforms. In order to illustrate the validity of the system, a series of model tests were conducted at a scale of 1:40. The coupled motion characteristics of the floating mooring platforms were discussed under regular and irregular waves, and the influences of wave direction and other characteristics on dynamic response of the system were analyzed. The results show that the mooring system is safest at 0˚of wave incident angle, whereas the most dangerous mooring state occurs at 90˚ of wave incident angle. Motion responses increase with the increase of wave height, but are not linearly related to changes in wave height.

  17. Storage of hydrogen in floating catalytic carbon nanotubes after graphitizing

    Institute of Scientific and Technical Information of China (English)

    朱宏伟; 李雪松; 慈立杰; 徐才录; 毛宗强; 梁吉; 吴德海

    2002-01-01

    Hydrogen storage under moderate pressure (~10 Mpa) and ambient temperature (~25℃) in multi-walled carbon nanotubes (MWNTs) prepared by the floating catalyst method is investigated. The capacity of hydrogen adsorption is evaluated based on both the nanotubes diameter and morphology. Indirect evidence indicates that hydrogen adsorption not only occurs on tube surface and interiors, but also in tube interlayers. The results show that the floating catalytic carbon nanotubes might be a candidate hydrogen storage material for fuel cell electric vehicles.

  18. Study of a Floated Pendulum Accelerometer with Passive Magnetic Suspension

    OpenAIRE

    TAKIZAWA, Minoru; OOTSUKI, Masao; Suzuki, Takao; 滝沢, 実; 大月, 正男; 鈴木,孝雄

    1980-01-01

    In the last few years, in order to develop more precise inertial sensors, such as floated gyros and floated accelerometers used in the inertial navigation system, a passive magnetic suspension with an eight-pole stator, that can be applied to support the output axes of the sensors, has been theoretically and experimentally studied at NAL (National Aerospace Laboratory). In our previous reports, 7)~10)29) a theoretical analysis and an experimental study of the magnetic suspension were describe...

  19. Design of a reversible single precision floating point subtractor

    OpenAIRE

    Anantha Lakshmi, AV; Sudha, GF

    2014-01-01

    In recent years, Reversible logic has emerged as a major area of research due to its ability to reduce the power dissipation which is the main requirement in the low power digital circuit design. It has wide applications like low power CMOS design, Nano-technology, Digital signal processing, Communication, DNA computing and Optical computing. Floating-point operations are needed very frequently in nearly all computing disciplines, and studies have shown floating-point addition/subtraction to ...

  20. Breakwater Design for protection of floating houses in Haringvliet Region

    OpenAIRE

    Aggarwal, a; Vargas Solis, A.; Pasaoglu, M.; Harihar, S.; Wahida, S.; Wang, Q.

    2014-01-01

    A floating house development project to be constructed in the coast of Hellevoetsluis, in the municipality of Voorne-Putten, is under consideration. Within a project of this nature, several aspects need to be taken into account in order to safeguard the infrastructure against additional loadings to which regular houses are not exposed to. Hydrodynamic forcing could directly or indirectly cause damage and unpleasant displacements on the houses, as they float on the waters of the Harringvliet e...

  1. The effect of floating houses on water quality

    OpenAIRE

    Foka, E.; Rutten, M.; Boogaard, F. van de; de Graaf, R; Lima, R.; N. van de Giesen

    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 boards. Moreover, plans to incorporate floating houses in the urban planning have already been developed. However, the knowledge gap regarding the potential effect on the water quality halts the fur...

  2. Study on new float polishing with the MCF

    OpenAIRE

    Shimada, K.; Matsuo, Y.; Yamamoto, K; Zheng, Y.

    2007-01-01

    Purpose: As a continuation of a previous paper [1], the report demonstrates the various possibilities of float polishing utilizing the present improved magnetic compound fluid (MCF). The MCF developed by one of authors, Shimada, in 2001, was improved by the addition of α-cellulose, thereby achieving a clearance as great as 8mm as shown in another paper [1]. The present paper describes the possibility of the application of the MCF float polishing technique with α-cellulose.Design/methodology/a...

  3. Parametric time delay modeling for floating point units

    Science.gov (United States)

    Fahmy, Hossam A. H.; Liddicoat, Albert A.; Flynn, Michael J.

    2002-12-01

    A parametric time delay model to compare floating point unit implementations is proposed. This model is used to compare a previously proposed floating point adder using a redundant number representation with other high-performance implementations. The operand width, the fan-in of the logic gates and the radix of the redundant format are used as parameters to the model. The comparison is done over a range of operand widths, fan-in and radices to show the merits of each implementation.

  4. Floating-point multiple data stream digital signal processor

    Energy Technology Data Exchange (ETDEWEB)

    Fortier, M.; Corinthios, M.J.

    1982-01-01

    A microprogrammed multiple data stream digital signal processor is introduced. This floating-point processor is capable of implementing optimum Wiener filtering of signals, in general, and images in particular. Generalised spectral analysis transforms such as Fourier, Walsh, Hadamard, and generalised Walsh are efficiently implemented in a bit-slice microprocessor-based architecture. In this architecture, a microprogrammed sequencing section directly controls a central floating-point signal processing unit. Throughout, computations are performed on pipelined multiple complex data streams. 12 references.

  5. 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).

  6. Modelling large floating bodies in urban area flash-floods via a Smoothed Particle Hydrodynamics model

    Science.gov (United States)

    Albano, Raffaele; Sole, Aurelia; Mirauda, Domenica; Adamowski, Jan

    2016-10-01

    Large debris, including vehicles parked along floodplains, can cause severe damage and significant loss of life during urban area flash-floods. In this study, the authors validated and applied the Smoothed Particle Hydrodynamics (SPH) model, developed in Amicarelli et al. (2015), which reproduces in 3D the dynamics of rigid bodies driven by free surface flows, to the design of flood mitigation measures. To validate the model, the authors compared the model's predictions to the results of an experimental setup, involving a dam breach that strikes two fixed obstacles and three transportable floating bodies. Given the accuracy of the results, in terms of water depth over time and the time history of the bodies' movements, the SPH model explored in this study was used to analyse the mitigation efficiency of a proposed structural intervention - the use of small barriers (groynes) to prevent the transport of floating bodies. Different groynes configurations were examined to identify the most appropriate design and layout for urban area flash-flood damage mitigation. The authors found that groynes positioned upstream and downstream of each floating body can be effective as a risk mitigation measure for damage resulting from their movement.

  7. Profiling float-based observations of net respiration beneath the mixed layer

    Science.gov (United States)

    Hennon, Tyler D.; Riser, Stephen C.; Mecking, Sabine

    2016-06-01

    We employ profiling floats with dissolved oxygen sensors to observe in situ temporal oxygen evolution below the mixed layer, allowing us to characterize net respiration of organic carbon in eight distinct regions over the globe. Export and export efficiency are generally high in locations with strong seasonal variability and low in locations of weak seasonality. Vertically integrated respiration is weakly, yet significantly, correlated with remote observations of chlorophyll, net primary production, and planktonic community size structure. These correlations suggest that regimes of high net primary production and large phytoplankton fuel elevated respiration at depth. Several regions of float-based observations intersect with sites of other detailed observations (e.g., Hawaii and Sargasso Sea), which allows us to compare our results to independent studies. We find that there is good agreement among export production estimates at highly seasonal locations, and that float-based observations may be biased low at weakly seasonal locations. We posit that the reason for the low-latitude discrepancy is the relative steady state of oxygen concentration caused by weak seasonality and shallow wintertime mixed layer depths.

  8. 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

    2015-01-01

    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. PMID:26553524

  9. 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.

  10. Evaluation of floating impeller phenomena in a Gyro centrifugal pump.

    Science.gov (United States)

    Nishimura, Ikuya; Ichikawa, S; Mikami, M; Ishitoya, H; Motomura, T; Kawamura, M; Linneweber, J; Glueck, J; Shinohara, T; Nosé, Y

    2013-01-01

    The Gyro centrifugal pump developed as a totally implantable artificial heart was designed with a free impeller, in which the rotational shaft (male bearing) of the impeller was completely separated from the female bearing. For this type of pump, it is very important to keep the proper magnet balance (impeller-magnet and actuator-magnet) in order to prevent thrombus formation and/or bearing wear. When the magnet balance is not proper, the impeller is jerked down into the bottom bearing. On the other hand, if magnet balance is proper, the impeller lifted off the bottom of the pump housing within a certain range of pumping conditions. In this study, this floating phenomenon was investigated in detail. The floating phenomenon was proved by observation of the impeller behavior using a transparent acrylic pump. The impeller floating phenomenon was mapped on a pump performance curve. The impeller floating phenomenon is affected by the magnet-magnet coupling distance and rotational speed of the impeller. In order to keep the proper magnet balance and to maintain the impeller floating phenomenon at the driving condition of right and left pump, the magnet-magnet coupling distance was altered by a spacer which was installed between the pump and actuator. It became clear that the same pump could handle different conditions (right and left ventricular assist), by just changing the thickness of the spacer. When magnet balance is proper, the floating impeller phenomenon occurs automatically in response to the impeller rev. It is called "the dynamic RPM suspension".

  11. 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.

  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. 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.

  14. 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;

    2013-01-01

    technology, which can be improved in the future with new dedicated technological solutions. The rotor uses curved blades, which are designed in order to minimize the gravitational loads and to be produced by the pultrusion process. The floating platform is a slender cylindrical structure rotating along......-DTU. The numerical simulations take into account the fully coupled aerodynamic and hydrodynamic loads on the structure, due to wind, waves and currents. The turbine is tested in operative conditions, at different sea states, selected according to the international offshore standards. The research is part...

  15. Entropie analysis of floating car data systems

    Directory of Open Access Journals (Sweden)

    F. Gössel

    2004-01-01

    Full Text Available The knowledge of the actual traffic state is a basic prerequisite of modern traffic telematic systems. Floating Car Data (FCD systems are becoming more and more important for the provision of actual and reliable traffic data. In these systems the vehicle velocity is the original variable for the evaluation of the current traffic condition. As real FCDsystems are operating under conditions of limited transmission and processing capacity the analysis of the original variable vehicle speed is of special interest. Entropy considerations are especially useful for the deduction of fundamental restrictions and limitations. The paper analyses velocity-time profiles by means of information entropy. It emphasises in quantification of the information content of velocity-time profiles and the discussion of entropy dynamic in velocity-time profiles. Investigations are based on empirical data derived during field trials. The analysis of entropy dynamic is carried out in two different ways. On one hand velocity differences within a certain interval of time are used, on the other hand the transinformation between velocities in certain time distances was evaluated. One important result is an optimal sample-rate for the detection of velocity data in FCD-systems. The influence of spatial segmentation and of different states of traffic was discussed.

  16. Floating geomembrane cover improves biogas collection

    Energy Technology Data Exchange (ETDEWEB)

    McMahon, J.

    2009-07-15

    Canadian corn products refiner, Casco Inc., recently upgraded a wastewater anaerobic digester at its automated corn wet milling facility on the St. Lawrence River, in Cardinal Ontario. The upgrade includes an improved floating and insulated geomembrane cover, designed and installed by Geomembrane Technologies Inc. The cover effectively streamlines biogas collection, improves biogas odour control and optimizes bioreactor heat retention. Casco's bulk volume fermenter (BVF) was designed and built in 1988 by ADI Systems Inc. It is limited to receiving 641,000 gallons of wastewater per day from several areas of the plant. Wastewater sludge is usually treated by anaerobic digestion. At Casco, raw solids are added directly to the BVF bioreactor, where they are digested, minimizing waste sludge handling. In essence, anaerobic digestion is a renewable energy source which converts wastewater to a methane- and carbon dioxide-rich biogas suitable for energy production, replacing fossil fuels. The insulated geomembrane cover captures and reclaims all the biogas from the treatment process that is going on inside the tank. Without a cover, the biogas would be released to the atmosphere. The new geomembrane cover collects an average of 236,000 cubic feet of biogas per day, at a 65 per cent methane concentration, from the BVF bioreactor. 2 figs.

  17. Residents' perceptions of a night float system

    Directory of Open Access Journals (Sweden)

    Granieri Rosanne

    2009-08-01

    Full Text Available Abstract Background A Night Float (NF system has been implemented by many institutions to address increasing concerns about residents' work hours. The purpose of our study was to examine the perceptions of residents towards a NF system. Methods A 115-item questionnaire was developed to assess residents' perceptions of the NF rotation as compared with a regular call month. The categories included patient care, education, medical errors, and overall satisfaction. Internal Medicine housestaff (post-graduate years 1–3 from three hospital settings at the University of Pittsburgh completed the questionnaire. Results The response rate was 90% (n = 149. Of these, 74 had completed the NF rotation. The housestaff felt that the quality of patient care was improved because of NF (41% agreed and 18% disagreed. A majority also felt that better care was provided by a rested physician in spite of being less familiar with the patient (46% agreed and 21% disagreed. Most felt that there was less emphasis on education (65% and more emphasis on service (52% during NF. Overall, the residents felt more rested during their call months (83% and strongly supported the 80-hour workweek requirement (77%. Conclusion Housestaff felt that the overall quality of patient care was improved by a NF system. The perceived improved quality of care by a rested physician coupled with a perceived decrease in the emphasis on education may have significant implications in housestaff training.

  18. Floating point representations in quantum circuit synthesis

    Science.gov (United States)

    Wiebe, Nathan; Kliuchnikov, Vadym

    2013-09-01

    We provide a non-deterministic quantum protocol that approximates the single qubit rotations Rx(2ϕ21ϕ22) using Rx(2ϕ1) and Rx(2ϕ2) and a constant number of Clifford and T operations. We then use this method to construct a ‘floating point’ implementation of a small rotation wherein we use the aforementioned method to construct the exponent part of the rotation and also to combine it with a mantissa. This causes the cost of the synthesis to depend more strongly on the relative (rather than absolute) precision required. We analyze the mean and variance of the T-count required to use our techniques and provide new lower bounds for the T-count for ancilla free synthesis of small single-qubit axial rotations. We further show that our techniques can use ancillas to beat these lower bounds with high probability. We also discuss the T-depth of our method and see that the vast majority of the cost of the resultant circuits can be shifted to parallel computation paths.

  19. Certifying floating-point implementations using Gappa

    CERN Document Server

    De Dinechin, Florent; Melquiond, Guillaume

    2008-01-01

    High confidence in floating-point programs requires proving numerical properties of final and intermediate values. One may need to guarantee that a value stays within some range, or that the error relative to some ideal value is well bounded. Such work may require several lines of proof for each line of code, and will usually be broken by the smallest change to the code (e.g. for maintenance or optimization purpose). Certifying these programs by hand is therefore very tedious and error-prone. This article discusses the use of the Gappa proof assistant in this context. Gappa has two main advantages over previous approaches: Its input format is very close to the actual C code to validate, and it automates error evaluation and propagation using interval arithmetic. Besides, it can be used to incrementally prove complex mathematical properties pertaining to the C code. Yet it does not require any specific knowledge about automatic theorem proving, and thus is accessible to a wide community. Moreover, Gappa may ge...

  20. Traumatic Floating Clavicle- A case report

    Science.gov (United States)

    Sopu, Alexandra; Green, Connor; Molony, Diarmuid

    2015-01-01

    Introduction: Shoulder injuries after high velocity trauma are common. Clavicle is affected in almost half of these cases. Even so, bipolar dislocation of the clavicle is an unusual injury and seldom reported in the literature. Conservative management is used for almost all the cases and only selected cases will undergo surgical treatment. Case Report: A 52 year old right electrician presented to the emergency department following a fall from a push bicycle. Plain radiographs identified a left first metacarpal (MC) fracture and a bipolar fracture of his right clavicle. Following Fracture Clinic review, significant deformity of the medial clavicle was noted and a CT scan showed anterior dislocation of the medial fragment. Given the degree of deformity and this functional requirement we felt that operative treatment was most appropriate for his unstable medial clavicle fracture dislocation. Conclusion: Surgical treatment of floating clavicle has an important role in the management of fit and active patients. It is important to identify the mechanism of injury and deforming forces in fractures and only after this to plan to neutralise these where appropriate. PMID:27299032

  1. 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.)

  2. Sphingolipid signalling domains floating on rafts or buried in caves?

    Science.gov (United States)

    Dobrowsky, R T

    2000-02-01

    Ceramide is a novel lipid mediator involved in regulating cell growth, cell differentiation and cell death. Many studies have focused on characterizing the stimulus-induced production of ceramide and identifying putative downstream molecular targets. However, little remains known about the localization of the regulated production of ceramide through sphingomyelin metabolism in the plasma membrane. Additionally, it is unclear whether a localized increase in ceramide concentration is necessary to facilitate downstream signalling events initiated by this lipid. Recent studies have suggested that detergent-insoluble plasma membrane domains may be highly localized sites for initiating signal transduction cascades by both tyrosine kinase and sphingolipid signalling pathways. These domains are typically enriched in both sphingolipids and cholesterol and have been proposed to form highly ordered lipid rafts floating in a sea of glycerophospholipids. Alternatively, upon integration of the cholesterol binding protein caveolin, these domains may also form small cave-like structures called caveolae. Emerging evidence suggests that the enhanced sphingomyelin content of these lipid domains make them potential substrate pools for sphingomyelinases to produce a high local concentration of ceramide. The subsequent formation of ceramide microdomains in the plasma membrane may be a critical factor in regulating downstream signalling through this lipid messenger.

  3. Hydraulic behaviour of the floating wave energy converter Wave Dragon

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    The objective of the project is to establish a scale 1:4.5 test model of the floating offshore wave energy converter - Wave Dragon - for testing at 5 m water depth in the Inlet Nissum Bredning. The test model will be equipped with an existing diameter 340 mm model turbine plus additional outlet tubes simulating the resistance from 1 - 16 turbines. The model will be designed to stay afloat even with a total loss of air pressure in the open bottom buoyancy chambers. The test series will primarily focus on measurements of hydraulic response, forces in the mooring system and overtopping quantities. Also data such as head, rotational speed and power production from the turbine will be monitored during the whole test period. The project will verify the effect of the pressured air buoyancy system, which cannot be scaled correctly in laboratory scale models. The test results will allow for an evaluation of the Wave Dragon power production as a function of sea state and freeboard height, in order to calibrate the existing WD-power simulation software. The model can be utilized for further testing of turbine regulation and stress and strain in the structure, establishing the necessary knowledge base for deploying a full-scale demonstration plant. This CD-ROM contains various videos, reports, notes, conference papers and Power Point presentations on the making of the wave energy converter Wave Dragon. (BA)

  4. A Design Outline for Floating Point Absorber Wave Energy Converters

    Directory of Open Access Journals (Sweden)

    Mohammed Faizal

    2014-04-01

    Full Text Available An overview of the most important development stages of floating point absorber wave energy converters is presented. At a given location, the wave energy resource has to be first assessed for varying seasons. The mechanisms used to convert wave energy to usable energy vary for different wave energy conversion systems. The power output of the generator will have variations due to varying incident waves. The wave structure-interaction leads to modifications in the incident waves; thus, the power output is also affected. The device has to be stable enough to prevent itself from capsizing. The point absorber will give optimum performance when the incident wave frequencies correspond to the natural frequency of the device. The methods for calculating natural frequencies for pitching and heaving systems are presented. Mooring systems maintain the point absorber at the desired location. Various mooring configurations as well as the most commonly used materials for mooring lines are discussed. An overview of scaled modelling is also presented.

  5. Design of a reversible single precision floating point subtractor.

    Science.gov (United States)

    Anantha Lakshmi, Av; Sudha, Gf

    2014-01-04

    In recent years, Reversible logic has emerged as a major area of research due to its ability to reduce the power dissipation which is the main requirement in the low power digital circuit design. It has wide applications like low power CMOS design, Nano-technology, Digital signal processing, Communication, DNA computing and Optical computing. Floating-point operations are needed very frequently in nearly all computing disciplines, and studies have shown floating-point addition/subtraction to be the most used floating-point operation. However, few designs exist on efficient reversible BCD subtractors but no work on reversible floating point subtractor. In this paper, it is proposed to present an efficient reversible single precision floating-point subtractor. The proposed design requires reversible designs of an 8-bit and a 24-bit comparator unit, an 8-bit and a 24-bit subtractor, and a normalization unit. For normalization, a 24-bit Reversible Leading Zero Detector and a 24-bit reversible shift register is implemented to shift the mantissas. To realize a reversible 1-bit comparator, in this paper, two new 3x3 reversible gates are proposed The proposed reversible 1-bit comparator is better and optimized in terms of the number of reversible gates used, the number of transistor count and the number of garbage outputs. The proposed work is analysed in terms of number of reversible gates, garbage outputs, constant inputs and quantum costs. Using these modules, an efficient design of a reversible single precision floating point subtractor is proposed. Proposed circuits have been simulated using Modelsim and synthesized using Xilinx Virtex5vlx30tff665-3. The total on-chip power consumed by the proposed 32-bit reversible floating point subtractor is 0.410 W.

  6. Stable Failure-Inducing Micro-Silica Aqua Epoxy Bonding Material for Floating Concrete Module Connection

    Directory of Open Access Journals (Sweden)

    Jang-Ho Jay Kim

    2015-11-01

    Full Text Available Many recent studies in the development of floating concrete structures focused on a connection system made of modules. In the connection system, the modules are designed to be attached by pre-stressing (PS while floating on the water, which exposes them to loads on the surface of the water. Therefore, the development of a pre-connection material becomes critical to ensure successful bonding of floating concrete modules. Micro-silica mixed aqua-epoxy (MSAE was developed for this task. To find the proper MSAE mix proportion, 0% to 4% micro-silica was mixed in a standard mixture of aqua-epoxy for material testing. Also, the effect of micro-silica on the viscosity of the aqua epoxy was evaluated by controlling the epoxy silane at proportions of 0%, ±5%, and ±10%. After completion of the performance tests of the MSAE, we evaluated the effect of MSAE in a connected structure. The plain unreinforced concrete module joint specimens applied with MSAE at thicknesses of 5, 10, and 20 mm were prepared to be tested. Finally, we evaluated the performance of MSAE-applied reinforced concrete (RC module specimens connected by PS tendons, and these were compared with those of continuous RC and non-MSAE-applied beams. The results showed that the mix of micro-silica in the aqua-epoxy changed the performance of the aqua-epoxy and the mix ratio of 2% micro-silica gave a stable failure behavior. The flexural capacity of concrete blocks bonded with MSAE changed according to the bond thickness and was better than that of concrete blocks bonded with aqua-epoxy without micro-silica. Even though MSAE insignificantly increases the load-carrying capacity of the attached concrete module structure, the stress concentration reduction effect stabilized the failure of the structure.

  7. Combustion of liquid fuels floating on water

    Directory of Open Access Journals (Sweden)

    Garo Jean-Pierre

    2007-01-01

    Full Text Available The research presented consists of a study of the burning characteristics of a liquid fuel floating on water with emphasis in the phenomena known as boilover. The problem is of technical interest in the petro-chemical industry, particularly from the point of view of pollution and fires resulting from accidental liquid fuel spills in open water. Testing with multicomponent fuels gives information's about events that can occur in a practical situation, while testing with single component fuels permits obtaining fundamental information about the problem. It evidences the major effects caused by the transfer of heat from the fuel to the water underneath. One of these effects is the disruptive burning of the fuel known as boilover, that is caused by the water boiling and splashing, and results in a sharp increase in burning rate and often in the explosive burning of the fuel. It is shown that this event is caused by the onset of water boiling nucleation at the fuel/water interface and that it occurs at an approximate constant temperature that is above the saturation temperature of the water (water is superheated. These measurements conducted in two laboratories, address the major issues of the process by analyzing the effect of the variation of the parameters of the problem (initial fuel-layer thickness, pool diameter, and fuel type, on the burning rate, time to start of boilover, pre-boilover mass ratio, and boilover intensity. Finally, two types of modeling are proposed to describe the heat transfer in fuel and water phases: one simple for practical purposes, the other, more elaborated and transient, taking particularly into consideration the radiation in depth.

  8. 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.

  9. A Fast Floating Point Double Precision Implementation on Fpga

    Directory of Open Access Journals (Sweden)

    Monika Maan

    2016-06-01

    Full Text Available In the modern day digital systems, floating point units are an important component in many signal and image processing applications. Many approaches of the floating point units have been proposed and compared with their counterparts in recent years. IEEE 754 floating point standard allows two types of precision units for floating point operations, single and double. In the proposed architecture double precision floating point unit is used and basic arithmetic operations are performed. A parallel architecture is proposed along with the high speed adder, which is shared among other operations and can perform operations independently as a separate unit. To improve the area efficiency of the unit, carry select adder is designed with the novel resource sharing technique which allows performing the operations with the minimum usage of the resources while computing the carry and sum for „0‟ and „1‟. The design is implemented using the Xilinx Spartan 6 FPGA and the results show the 23% improvement in the speed of the designed circuit.

  10. Control implementation for the SPUR floating point coprocessor

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, D.

    1987-01-01

    SPUR is a RISC-based multiprocessor workstation being designed to facilitate parallel-processing research. Typically, RISC architectures achieve low performance levels for floating-point intensive applications, as the multiple-cycle floating-point instructions are not implemented in the hardware. In an attempt to raise these performance levels, the SPUR system provides floating-point support through an extended instruction set and tightly-coupled floating-point coprocessor. This report documents the implementation of the control unit for this floating-point coprocessor; describing the coprocessor interface, control PLA definitions, the finite state machine, the dynamic cycle counter, the 4-stage load-store pipeline, and the random logic generated to drive the datapath modules. Implementation techniques and trade-offs are discussed; including design strategy, area and speed optimization, noise margin considerations, and delay balancing rf the datapath control signals for clock skew minimization. Finally, in an attempt to raise these performance levels, the SPUR system The chip is implemented in 2-layer-metal 2..mu..m CMOS technology, and uses a four-phase non-overlapping clock with a target cycle time of approximately 100ns - 140 ns.

  11. 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.

  12. The coolest 'stars' are free-floating planets

    CERN Document Server

    Joergens, V; Liu, Y; Bayo, A; Wolf, S

    2014-01-01

    We show that the coolest known object that is probably formed in a star-like mode is a free-floating planet. We discovered recently that the free-floating planetary mass object OTS,44 (M9.5, ~12 Jupiter masses, age ~2 Myr) has significant accretion and a substantial disk. This demonstrates that the processes that characterize the canonical star-like mode of formation apply to isolated objects down to a few Jupiter masses. We detected in VLT/SINFONI spectra that OTS44 has strong, broad, and variable Paschen beta emission. This is the first evidence for active accretion of a free-floating planet. The object allows us to study accretion and disk physics at the extreme and can be seen as free-floating analog of accreting planets that orbit stars. Our analysis of OTS44 shows that the mass-accretion rate decreases continuously from stars of several solar masses down to free-floating planets. We determined, furthermore, the disk mass (10 Earth masses) and further disk properties of OTS44 through modeling its SED inc...

  13. Residence adaptable design of city low income floating population%城市低收入流动人口住宅适应性设计

    Institute of Scientific and Technical Information of China (English)

    马小凤

    2012-01-01

    通过分析城市低收入流动人口年龄组成、家庭构成及生活方式等因素及相应的居住需求,从套型内和套型间两方面探讨了低收入流动人口住宅适应性的设计策略,对以后流动人口住宅的建设和发展具有一定指导作用。%Through the analysis on the age structure,family structure,lifestyle and other factors of city low income floating population and the corresponding resident demand,this paper discussed the design strategy of residence adaptable of low income floating population from dwelling size inside and dwelling size room,had a certain guiding role for the construction and development of residence of floating population.

  14. Performance Calculation of Floating Wind Turbine Tension Leg Platform in the South China Sea

    Directory of Open Access Journals (Sweden)

    Hai Feng Wang

    2015-10-01

    Full Text Available The harvesting of wind energy is expected to increase greatly in the future because of its stability, abundance, and renewability in large coastal states such as China. The floating support structure will likely become the major structural form for wind turbines in the future due to its cost advantages when the water depth reaches 50 m. The 5MW wind turbine model from National Renewable Energy Lab (NREL and the modified tension leg platform model proposed by Harbin Institute of Technology (HIT were applied to certain sea conditions in the South China Sea in order to consider the effects of external load coupling actions. In this study, the internal force, mooring system force, as well as the acceleration, displacement and velocity of the floating structure of the modified HIT Tension Leg Platform (HIT-TLP were calculated. During this process, the physical parameters of its tension leg structure at a specific frequency domain were obtained to find the technical reserves for its practical application in the future.

  15. Laser and alpha particle characterization of floating-base BJT detector

    Energy Technology Data Exchange (ETDEWEB)

    Tyzhnevyi, V., E-mail: tyzhnevyi@disi.unitn.i [Universita di Trento and INFN Trento, Trento (Italy); Batignani, G. [Dipartimento di Fisica, Universita di Pisa and INFN Pisa, Pisa (Italy); Bosisio, L. [Dipartimento di Fisica, Universita di Trieste and INFN Trieste, Trieste (Italy); Dalla Betta, G.-F. [Universita di Trento and INFN Trento, Trento (Italy); Verzellesi, G. [Universita di Modena e Reggio Emilia and INFN Trento, Reggio Emilia (Italy); Zorzi, N. [Fondazione Bruno Kessler (FBK), Trento (Italy)

    2010-05-21

    In this work, we investigate the detection properties of existing prototypes of BJT detectors operated with floating base. We report about results of two functional tests. The charge-collection properties of BJT detectors were evaluated by means of a pulsed laser setup. The response to {alpha}-particles emitted from radioactive {sup 241}Am source are also presented. Experimental results show that current gains of about 450 with response times in the order of 50 {mu}s are preserved even in this non-standard operation mode, in spite of a non-optimized structure.

  16. Balancing rotor speed regulation and drive train loads of floating wind turbines

    Science.gov (United States)

    Fischer, Boris; Loepelmann, Peter

    2016-09-01

    The interaction of the blade pitch controller with structural motion is particularly important for wind turbines mounted on floating platforms. A controls-based approach to overcome the related technical challenges is to feed back the nacelle's motion to the demanded generator torque. This work aims to further improve this approach by feeding back only a narrow fraction of the available frequency range. Simulations show that, in doing so, unrealistically high torque magnitudes are avoided, and better a trade-off between rotor speed regulation and drive train loads is achieved.

  17. Polyester mooring stiffness modeling for deepwater floating system

    Institute of Scientific and Technical Information of China (English)

    Chen Yongjun; Qu Yan; Zhang Tianyu

    2013-01-01

    Polyester mooring has become increasing popular to serve as permanent station-keeping system for deepwater floating system during recent years.Comparing to the traditional steel wire mooring,polyester mooring provides significant benefits in deepwater,such as reduced installed capital expenditure (CAPEX) and smaller vertical loads on host platform.Polyester rope is a visco-elastic material,and its stiffness is nonlinear and affected by mean load,load range,loading period and loading history.There is a perception that the polyester stiffness model has significant impact on the floating system' s performance.This paper presents a detailed description and comparison of two stiffness models and three analytic approaches,and provides a systematic study of the impact of polyester mooring stiffness modeling on the deepwater floating system performance.

  18. 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.

  19. 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.

  20. Study on Wood Drying Properties under Vacuum-floating Pressure

    Institute of Scientific and Technical Information of China (English)

    ZHANGBiguang; YISonghn; CHANGJianmin; LIXianjun

    2004-01-01

    Using Masson pine as specimens, when drying mediums are overheated steam and hot-air respectively, preheating characteristics of wood under vacuum-floating pressure drying are discussed by measurement of internal temperature field and variation of moisture content during period of preheating. The relationship between drying medium conditions and drying rate of wood reveals that, firstly, compared with process of air-drying, time needed to be preheated under vacuum-floating decreased dramatically, meanwhile,the magnitude of condensation on the surface is relatively larger. Secondly, drying rate of wood under vacuum-floating pressure increases coupled with temperature of medium, reduction of absolute pressure,and raise of fluctuation rate of pressure. The sequence of factors contribution to drying rate is listed as following: temperature of medium (t) > fluctuation rate of pressure (f)> absolute pressure (p).

  1. 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.

  2. Floating point hardware emulator for RSX-11D

    Energy Technology Data Exchange (ETDEWEB)

    Kellogg, M.; Long, M.

    1977-01-01

    An RSX-11D task was written to simulate the FP-11 floating point hardware on systems that lack this hardware. The simulation is transparent to tasks using floating point instructions. All normal features of the hardware are simulated exactly, including its action on exception conditions. The emulator is a privileged task occupying about 2.7K words of memory. When it is loaded and run, it sets up a linkage to intercept the reserved instruction trap before it reaches the executive, and route it to a service routine that can decode and simulate the floating point instruction set. The results of a benchmark timing test are given, as are notes on converting the emulator to run under RSX-11M. 1 figure, 2 tables.

  3. VLSI design techniques for floating-point computation

    Energy Technology Data Exchange (ETDEWEB)

    Bose, B. K.

    1988-01-01

    The thesis presents design techniques for floating-point computation in VLSI. A basis for area-time design decisions for arithmetic and memory operations is formulated from a study of computationally intensive programs. Tradeoffs in the design and implementation of an efficient coprocessor interface are studied, together with the implications of hardware support for the IEEE Floating-Point Standard. Algorithm area-time tradeoffs for basic arithmetic functions are analyzed in light of changing technology. Details of a single-chip floating-point unit designed in two-micron CMOS for SPUR are described, including special design considerations for very wide data paths. The pervasive effects of scaling technology on different levels of design are explored, from devices and circuits, through logic and micro-architecture, to algorithms and systems.

  4. Floating plastic debris in the Central and Western Mediterranean Sea.

    Science.gov (United States)

    Ruiz-Orejón, Luis F; Sardá, Rafael; Ramis-Pujol, Juan

    2016-09-01

    In two sea voyages throughout the Mediterranean (2011 and 2013) that repeated the historical travels of Archduke Ludwig Salvator of Austria (1847-1915), 71 samples of floating plastic debris were obtained with a Manta trawl. Floating plastic was observed in all the sampled sites, with an average weight concentration of 579.3 g dw km(-2) (maximum value of 9298.2 g dw km(-2)) and an average particle concentration of 147,500 items km(-2) (the maximum concentration was 1,164,403 items km(-2)). The plastic size distribution showed microplastics (<5 mm) in all the samples. The most abundant particles had a surface area of approximately 1 mm(2) (the mesh size was 333 μm). The general estimate obtained was a total value of 1455 tons dw of floating plastic in the entire Mediterranean region, with various potential spatial accumulation areas.

  5. Expanded polystyrene (EPS) floats for surveillance of Ochlerotatus japonicus.

    Science.gov (United States)

    Scott, Jamesina J; Crans, Wayne J

    2003-12-01

    Blocks of expanded polystyrene (EPS) were placed in a variety of habitats to investigate their potential as an egg-collection device for container-dwelling Aedes and Ochlerotatus species. Eggs from Ochlerotatus japonicus, Oc. triseriatus, Oc. hendersoni, and Aedes albopictus were collected with EPS floats. The float provides an inexpensive, low-maintenance alternative to the Centers for Disease Control ovitrap for sampling container-dwelling mosquito species that are important vectors of disease. Eggs collected on the floats have many potential applications, including use in routine population surveillance; detection of Oc. japonicus, Ae. albopictus, and other container-dwelling species in new areas; species distribution studies; natural transovarial transmission studies; ovipositional studies; collection of local field populations for insecticide resistance assays; assessment of adulticiding efficacy; and establishment of new laboratory colonies.

  6. MULTIMERMAID: A dedicated multichannel seismic/weather/zoological float for monitoring of the oceans

    Science.gov (United States)

    Hello, Y. M.; Bonnieux, S.; Joubert, C.; Sukhovich, A.; Argentino, J.; Yegikyan, M.; Nolet, G.

    2013-12-01

    , drizzle, open sea and ice, or whale migration. This extension to multi-purpose applications makes the Mermaid very attractive for the Argo program. In fact, Mermaids using passive low cost sensors form a very light and complementary solution that can easily be integrated with an Argo float since CTD data are taken during ascent. Such multidisciplinary approach should allow seismologists to participate in international programs such as Argo and obtain the dense ocean coverage needed to image the deep structure of the Earth. We estimate that about 300 Mermaids, operated over a time span of five years, can provide a ray coverage beneath the oceans comparable to that now available beneath the continents with the Global Seismic Network (GSN). To compensate for the extra energy needed for multidisciplinary applications, Geoazur and Osean are developing a new float, called Multimermaid, that uses the same 17' glass sphere as the Ocean Bottom Seismometers constructed by Geoazur. The Multimermaid can navigate up to a depth of 3000 m and hold 2.5 times more battery power than a conventional float.

  7. Floating knee injuries: Results of treatment and outcomes

    Directory of Open Access Journals (Sweden)

    Mohammad Hadi Nouraei

    2013-01-01

    Full Text Available Background: Floating knee, referred to as ipsilateral fractures of the femur and tibia, is usually associated with several complications and mortality. This study was designed to present our experience with treatment of this injury throughout; age, sex, mechanism of injury, associated injuries, method and results of treatment, and complications of floating knee are discussed. Materials and Methods: This retrospective study was performed between January 2006 and December 2011. All patients with floating knee injuries who were admitted to the referral educational hospitals were included. The information about the 238 cases of floating knee injuries were gathered through the 254,620 trauma files and after excluding 18 patients who died within 6 months, the remaining files were studied and the target information was recorded. Results: The most frequent age group was 20-29 years (44.5%. The floating knee injuries were more common in males (85.5%. Type (D according to "the classification of Letts and Vincent" was observed in 38.9% cases. The most frequent mechanism of injury was car to motorcycles accidents (48.2%. The most common associated injury was pelvic fractures (86.8%. Open reduction and internal fixation was the common type of treatment (70%. The most common early and late complications were knee hemarthrosis in 31 cases (14% and knee osteoarthritis in 30 cases (13.6%, respectively. Death during the 5 years follow up was due to circulatory disruption, followed by deep vein thrombosis (61%. There was a significant relation between the age and outcomes as it worsens with age (P-value < 0.05. Conclusion: This study revealed that the complication rate associated with floating knee injuries remained high, regardless of the used treatment regimen and surgeons should focus on reducing complications while treating it.

  8. Bifurcated method and apparatus for floating point addition with decreased latency time

    Energy Technology Data Exchange (ETDEWEB)

    Farmwald, Paul M. (Livermore, CA)

    1987-01-01

    Apparatus for decreasing the latency time associated with floating point addition and subtraction in a computer, using a novel bifurcated, pre-normalization/post-normalization approach that distinguishes between differences of floating point exponents.

  9. 14 CFR 23.529 - Hull and main float landing conditions.

    Science.gov (United States)

    2010-01-01

    ... midway between the keel and chine lines. (c) Unsymmetrical landing; twin float seaplanes. The..., perpendicularly to the plane of symmetry midway between the keel and chine lines of the float, at the...

  10. 14 CFR 25.529 - Hull and main float landing conditions.

    Science.gov (United States)

    2010-01-01

    ... chine lines. (c) Unsymmetrical landing; twin float seaplanes. The unsymmetrical loading consists of an... symmetry midway between the keel and chine lines of the float, at the same longitudinal station as...

  11. Efficient Hybrid Method for Binary Floating Point Multiplication

    Directory of Open Access Journals (Sweden)

    S. Praveenkumar Reddy,

    2014-04-01

    Full Text Available This paper presents a high speed binary floating point multiplier based on Hybrid Method. To improve speed multiplication of mantissa is done using Hybrid method replacing existing multipliers like Carry Save Multiplier, Dadda Multiplier and Modified Booth Multiplier. Hybrid method is a combination of Dadda Multiplier and Modified Radix-8 Booth Multiplier. The design achieves high speed with maximum frequency of 555 MHz compared to existing floating point multipliers. The multiplier implemented in Verilog HDL and analyzed in Quartus II 10.0 version. Hybrid Multiplier is compared with existing multipliers.

  12. Transition to Chaos in the Floating Half Zone Convection

    Institute of Scientific and Technical Information of China (English)

    AA Yan; CAO Zhong-Hua; HU Wen-Rui

    2007-01-01

    The transition process from steady convection to chaos is experimentally studied in thermocapillary convections of floating half zone. The onset of temperature oscillations in the liquid bridge of floating half zone and further transitions of the temporal convective behaviour are detected by measuring the temperature in the liquid bridge.The fast Fourier transform reveals the frequency and amplitude characteristics of the flow transition. The experimental results indicate the existence of a sequence of period-doubling bifurcations that culminate in chaos.The measured Feigenbaum numbers are δ2 = 4.69 and δ4 = 4.6, which are comparable with the theoretical asymptotic value δ = 4.669.

  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. Study on the cluster of floating dross before nucleating during hot-dipping process

    Institute of Scientific and Technical Information of China (English)

    WEI; Yunhe; ZHANG; Changqiao; QIN; Jingyu; LIU; Chengbu

    2005-01-01

    During hot-dipping in molten Zn-55Al, the forming of "floating" dross is closely related with the interaction between the Al and the Fe atoms. Utilizing the thita-thita X-ray diffraction and the Percus-Yevick hard sphere model, this paper investigates the structure of molten Al3Fe that is an approximant of partial melt in practical Zn-55Al alloy melt. It is found that in the melt there exist clusters that resemble the structure of intermetallic compound Al3Fe. The strong interaction between Al and Fe atoms is also indicated by the deficiency of the coordination number from 12 and the shrinkage of averaged atomic diameter. Based on such information, it is speculated that in the molten Zn-55Al, with the accumulation of Fe, Al3Fe-like clusters form with priority, then grow into dross. On the other hand, after deflating of the effective hard sphere diameter of pure Al atom and enlarging that of the pure Fe atom, the modified model can achieve reasonable fit to the experimental structure factor. Hard sphere modeling also gave a good estimation of the mass density 3.65 g/cm3 of liquid Al3Fe alloy at 1550℃. Compared with the density of 3.7 g/cm3 of Zn-55Al, the reason for dross floating is satisfactorily understood.

  15. Operational Modal Analysis of a Spar-Type Floating Platform Using Frequency Domain Decomposition Method

    Directory of Open Access Journals (Sweden)

    Carlo Ruzzo

    2016-10-01

    Full Text Available System identification of offshore floating platforms is usually performed by testing small-scale models in wave tanks, where controlled conditions, such as still water for free decay tests, regular and irregular wave loading can be represented. However, this approach may result in constraints on model dimensions, testing time, and costs of the experimental activity. For such reasons, intermediate-scale field modelling of offshore floating structures may become an interesting as well as cost-effective alternative in a near future. Clearly, since the open sea is not a controlled environment, traditional system identification may become challenging and less precise. In this paper, a new approach based on Frequency Domain Decomposition (FDD method for Operational Modal Analysis is proposed and validated against numerical simulations in ANSYS AQWA v.16.0 on a simple spar-type structure. The results obtained match well with numerical predictions, showing that this new approach, opportunely coupled with more traditional wave tanks techniques, proves to be very promising to perform field-site identification of the model structures.

  16. Spatial distributions of floating seaweeds in the East China Sea from late winter to early spring

    OpenAIRE

    Mizuno, S.; Ajisaka, T.; Lahbib, S.; Kokubu, Y.; Alabsi, M. N.; Komatsu, T

    2013-01-01

    Floating seaweeds play an important role as a habitat for many animals accompanying or attaching to them in offshore waters. It was in 2000 that the first report described abundant distributions of floating seaweeds in offshore waters in the East China Sea in spring. Young individuals of the yellowtail Seriola quinqueradiata are captured for aquaculture purposes from floating seaweeds in the East China Sea. Therefore, a sound understanding of the distributions of floating seaweeds in the East...

  17. 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...

  18. 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.

  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. Floating Collection in an Academic Library: An Audacious Experiment That Succeeded

    Science.gov (United States)

    Coopey, Barbara; Eshbach, Barbara; Notartomas, Trish

    2016-01-01

    Can a floating collection thrive in a large multicampus academic research library? Floating collections have been successful in public libraries for some time, but it is uncommon for academic libraries and unheard of for a large academic library system. This article will discuss the investigation into the feasibility of a floating collection at…

  1. A statistical method for correcting salinity observations from autonomous profiling floats: An ARGO perspective

    Digital Repository Service at National Institute of Oceanography (India)

    Durand, F.; Reverdin, G.

    different algorithms were implemented and validated based on float-to-float data comparison at depth, where the water masses are relatively stable over the time scales of interest. The first algorithm is based upon objective analysis of the float data, while...

  2. Sabrewing: a lightweight architecture for combined floating-point and integer arithmetic

    NARCIS (Netherlands)

    Bruintjes, Tom M.; Walters, Karel H.G.; Gerez, Sabih H.; Molenkamp, Bert; Smit, Gerard J.M.

    2012-01-01

    In spite of the fact that floating-point arithmetic is costly in terms of silicon area, the joint design of hardware for floating-point and integer arithmetic is seldom considered. While components like multipliers and adders can potentially be shared, floating-point and integer units in contemporar

  3. 76 FR 52638 - Proposed Information Collection; Comment Request; Shipboard Observation Form for Floating Marine...

    Science.gov (United States)

    2011-08-23

    ... organizations (respondents) as well as numerous experts on marine debris observations at sea. The Shipboard Observation Form for Floating Marine Debris was created based on methods used in studies of floating marine... Observation Form for Floating Marine Debris AGENCY: National Oceanic and Atmospheric Administration...

  4. 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.

  5. 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.

  6. 低收入流动人口城市住宅初探%Discussion on the Housing for Low Income and Floating Population

    Institute of Scientific and Technical Information of China (English)

    张彧

    2001-01-01

    The problem of floating population has influences on the aspects of economics, society and culture of cities in China. This paper discusses age structure, life style, living concept of floating population in order to find the housing needs of floating population. Meanwhile, the author suggests to design and construct the house from different levels.%对影响流动人口住宅需求的深层层面,如流动人口家庭结构关系、生活行为、生活观念、生活关系,以及流动人口住宅消费等方面进行深入剖析。提出多元、多层次流动人口住宅设计概念,寻求解决低收入流动人口城市住宅设计的途径。

  7. An Asynchronous IEEE Floating-Point Arithmetic Unit

    Directory of Open Access Journals (Sweden)

    Joel R. Noche

    2007-12-01

    Full Text Available An asynchronous floating-point arithmetic unit is designed and tested at the transistor level usingCadence software. It uses CMOS (complementary metal oxide semiconductor and DCVS (differentialcascode voltage switch logic in a 0.35 µm process using a 3.3 V supply voltage, with dual-rail data andsingle-rail control signals using four-phase handshaking.Using 17,085 transistors, the unit handles single-precision (32-bit addition/subtraction, multiplication,division, and remainder using the IEEE 754-1985 Standard for Binary Floating-Point Arithmetic, withrounding and other operations to be handled by separate hardware or software. Division and remainderare done using a restoring subtractive algorithm; multiplication uses an additive algorithm. Exceptionsare noted by flags (and not trap handlers and the output is in single-precision.Previous work on asynchronous floating-point arithmetic units have mostly focused on single operationssuch as division. This is the first work to the authors' knowledge that can perform floating-point addition,multiplication, division, and remainder using a common datapath.

  8. 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.

  9. 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.

  10. Development and evaluation of gastroretentive norfloxacin floating tablets.

    Science.gov (United States)

    Bomma, Ramesh; Swamy Naidu, Rongala Appala; Yamsani, Madhusudan Rao; Veerabrahma, Kishan

    2009-06-01

    Floating matrix tablets of norfloxacin were developed to prolong gastric residence time, leading to an increase in drug bioavailability. Tablets were prepared by the wet granulation technique, using polymers such as hydroxypropyl methylcellulose (HPMC K4M, HPMC K100M) and xanthan gum. Tablets were evaluated for their physical characteristics, viz., hardness, thickness, friability, and mass variation, drug content and floating properties. Further, tablets were studied for in vitro drug release characteristics for 9 hours. The tablets exhibited controlled and prolonged drug release profiles while floating over the dissolution medium. Non-Fickian diffusion was confirmed as the drug release mechanism from these tablets, indicating that water diffusion and polymer rearrangement played an essential role in drug release. The best formulation (F4) was selected based on in vitro characteristics and was used in vivo radiographic studies by incorporating BaSO4. These studies revealed that the tablets remained in the stomach for 180 +/- 30 min in fasting human volunteers and indicated that gastric retention time was increased by the floating principle, which was considered desirable for the absorption window drugs.

  11. 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.

  12. Emulation of floating memcapacitors and meminductors using current conveyors

    CERN Document Server

    Pershin, Yuriy V

    2010-01-01

    We suggest circuit realizations of emulators transforming memristive devices into effective floating memcapacitive and meminductive systems. The emulator's circuits are based on second generation current conveyors and involve either four single-output or two dual-output current conveyors. The equations governing the resulting memcapactive and meminductive systems are presented.

  13. 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

  14. 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

  15. Breakwater Design for protection of floating houses in Haringvliet Region

    NARCIS (Netherlands)

    Aggarwal, A.; Vargas Solis, A.; Pasaoglu, M.; Harihar, S.; Wahida, S.; Wang, Q.

    2014-01-01

    A floating house development project to be constructed in the coast of Hellevoetsluis, in the municipality of Voorne-Putten, is under consideration. Within a project of this nature, several aspects need to be taken into account in order to safeguard the infrastructure against additional loadings to

  16. Mathematical modeling of floating stock policy in FMCG supply chains

    NARCIS (Netherlands)

    M. Pourakbar (Morteza); A.V. Sleptchenko (Andrei); R. Dekker (Rommert)

    2007-01-01

    textabstractThe floating stock distribution concept exploits inter-modal transport to deploy inventories in a supply chain in advance of retailer demand. It is appropriate in case of batch production and containerized transport of standard product mixes. In this way response times are reduced and st

  17. High speed matrix processors using floating point representation

    Energy Technology Data Exchange (ETDEWEB)

    Birkner, D.A.

    1980-01-01

    The author describes the architecture of a high-speed matrix processor which uses a floating-point format for data representation. It is shown how multipliers and other LSI devices are used in the design to obtain the high speed of the processor.

  18. Block floating-point notation for signal processes

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, J.E.

    1981-03-01

    The development and application of a notation for use with block floating-point (BFP) mathematical operations in real-time signal processes is described. The notation has been extensively used in developing perimeter security signal processors such as the Magnetic Intrusion Line Sensor (MILES) Adaptive Digital Processor (MADP) and its forerunner, the Signal Processing Development Unit (SSPDU).

  19. Benchmarks to supplant export FPDR (Floating Point Data Rate) calculations

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, D.; Brooks, E.; Dongarra, J.; Hayes, A.; Lyon, G.

    1988-06-01

    Because modern computer architectures render application of the FPDR (Floating Point Data Processing Rate) increasingly difficult, there has been increased interest in export evaluation via actual system performances. The report discusses benchmarking of uniprocessor (usually vector) machines for scientific computation (SIMD array processors are not included), and parallel processing and its characterization for export control.

  20. Wave Diffraction on Arc-Shaped Floating Perforated Breakwaters

    Institute of Scientific and Technical Information of China (English)

    DUAN Jin-hui; CHENG Jian-sheng; WANG Jian-ping; WANG Jing-quan

    2012-01-01

    An analytical method is developed to study the sheltering effects on arc-shaped floating perforated breakwaters.In the process of analysis,the floating breakwater is assumed to be rigid,thin,vertical,and immovable and located in water with constant depth.The fluid domain is divided into two regions by imaginary interface.The velocity potential in each region is expanded by eigenfunction in the context of linear theory.By satisfying continuity of pressure and normal velocity across the imaginary fluid interface,a set of linear algebraic equations can be obtained to determine the unknown coefficients for eigenfunction expansions.The accuracy of the present model was verified by a comparison with existing results for the case of arc-shaped floating breakwater.Numerical results,in the form of contour maps of the non-dimensional wave amplitude around the breakwater and diffracted wave amplitude at typical sections,are presented for a range of wave and breakwater parameters.Results show that the sheltering effects on the arc-shaped floating perforated breakwater are closely related to the incident wavelength,the draft and the porosity of the breakwater.

  1. Asymptomatic free-floating vitreous cyst masquerading as cysticercosis.

    Science.gov (United States)

    Ganger, Anita; Agarwal, Rinki; Kumar, Vinod

    2016-11-02

    A male patient aged 37 years, referred with the diagnosis of right eye intravitreal cysticercosis, was diagnosed as asymptomatic free-floating vitreous cyst after thorough evaluation. The patient was kept under observation, since baseline visual acuity was unaffected. No change was noted over the period of 6 months.

  2. 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.

  3. Experimental testing of moorings for large floating wave energy converters

    DEFF Research Database (Denmark)

    Thomsen, Jonas Bjerg; Ferri, Francesco; Kofoed, Jens Peter

    2016-01-01

    This paper presents the outcome of a test campaign, which investigates the behaviour of a synthetic mooring system applied to the Floating Power Plant wave energy converter. The study investigates the motion and tension response under operational and extreme sea states expected at the deployment...

  4. 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.

  5. Vibrations of a floating beam on marine waves

    Energy Technology Data Exchange (ETDEWEB)

    Sabaneev, Valentin S.; Tovstik, Petr E.; Tovstik, Tatiana M. [St.Petersburg University (Russian Federation); Shekhovtsov, Alexei S. [Architecture Institute, St.Petersburg (Russian Federation)

    2015-03-10

    Vertical vibrations of a floating pipe-concrete beam caused by a harmonic waves excitation are studied. The apparent additional mass of water, resisting force and the velocity of towing are considered. The vibration amplitude and the maximum deformations of concrete, caused by these fluctuations, are calculated.

  6. 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...

  7. Release kinetics of highly porous floating tablets containing cilostazol.

    Science.gov (United States)

    Hwang, Kyu-Mok; Cho, Cheol-Hee; Tung, Nguyen-Thach; Kim, Ju-Young; Rhee, Yun-Seok; Park, Eun-Seok

    2017-02-20

    This study focuses on developing a highly porous floating tablet containing cilostazol. The underlying release mechanism of cilostazol from porous and floating tablets in dissolution media containing surfactants was investigated. The tablets were prepared by compressing granules and excipients with a sublimating agent, followed by sublimation under vacuum. The volatile material for the sublimating agent was chosen based on its flow properties using conventional methods as well as the twisted blade method. Resultant tablets could float immediately and had significantly higher tensile strengths than conventional tablets of similar porosities, holding a promising potential for increasing gastroretentive properties. Fitting the release profiles to the Korsmeyer-Peppas equation indicated Super Case II, Case II and non-Fickian kinetics, which implied that the release was affected by both floating behavior and matrix erosion. Abrupt changes in release kinetic parameters and erosional behaviors were found between the tablets containing different amounts of HPMC, indicating the existence of an excipient percolation threshold. Neither the surfactant in the media nor the porosity affected the dominant release mechanism, which was matrix erosion. Understanding the dominant release mechanism and percolation threshold allows for tuning the formulation to obtain various release profiles.

  8. Extreme load predictions for floating offshore wind turbines

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    2009-01-01

    An effective stochastic procedure for extreme value predictions related to wave and wind induced stochastic loads is applied to a tension-leg concept for floating offshore wind turbines. The method is based on the First Order Reliability Method (FORM) and as the procedure makes use of only short...

  9. Issues in the study of floating universal numeric quantifiers

    NARCIS (Netherlands)

    R. Cirillo

    2010-01-01

    In the Germanic and Romance languages (among others) a universal quantifier can combine with a numeral and form a floating quantifier. I refer to these quantifiers as universal numeric quantifiers or simply ∀NumQ. The following examples from Dutch and Romanian demonstrate this phenomenon: The aim of

  10. Validation of a FAST Model of the Statoil-Hywind Demo Floating Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Driscoll, Frederick; Jonkman, Jason; Robertson, Amy; Sirnivas, Senu; Skaare, Bjorn; Nielsen, Finn Gunnar

    2016-09-01

    To assess the accuracy of the National Renewable Energy Laboratory's (NREL's) FAST simulation tool for modeling the coupled response of floating offshore wind turbines under realistic open-ocean conditions, NREL developed a FAST model of the Statoil Hywind Demo floating offshore wind turbine, and validated simulation results against field measurements. Field data were provided by Statoil, which conducted a comprehensive test measurement campaign of its demonstration system, a 2.3-MW Siemens turbine mounted on a spar substructure deployed about 10 km off the island of Karmoy in Norway. A top-down approach was used to develop the FAST model, starting with modeling the blades and working down to the mooring system. Design data provided by Siemens and Statoil were used to specify the structural, aerodynamic, and dynamic properties. Measured wind speeds and wave spectra were used to develop the wind and wave conditions used in the model. The overall system performance and behavior were validated for eight sets of field measurements that span a wide range of operating conditions. The simulated controller response accurately reproduced the measured blade pitch and power. The structural and blade loads and spectra of platform motion agree well with the measured data.

  11. 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.

  12. 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.

  13. FORMULATION AND EVALUATION OF FLOATING MATRIX TABLET OF RANITIDINE HYDROCHLORIDE

    Directory of Open Access Journals (Sweden)

    Himanshu D. Ravat

    2012-05-01

    Full Text Available Ranitidine HCl is used for the H2 receptor antagonist. It is an absorption window limited drug, whosesolubility decreases with increase in the pH and has a short half life of 2-3 h. Therefore the presentinvestigation is concerned with the development of the floating matrix tablets, which after oraladministration were designed to prolong the gastric residence time and thus to increase thebioavailability of the drug and its half life. Ranitidine HCl showed maximum absorption at wavelength324 nm in 0.1N HCl. Drug-polymer compatibility studies by DSC give conformation about their purityand showed no interaction between drug and selected polymers. Various formulations were developedby using release rate controlling and gel forming polymers like HPMC K4 M, and Polyethylene oxideWSR 303 in single by direct compression method with the incorporation of sodium bicarbonate as gasgenerating agent. All the formulations had floating lag time below 4 minutes and constantly floated ondissolution medium for more than 12 h. Swelling studies indicated significant water uptake andcontributed in drug release. From all the developed formulations, batch F5 and F6 prolonged the drugrelease for longer period of time, they were nominated as best formulations. The best formulationsfollowed power law kinetics while the drug release mechanism was found to be diffusion through andpolymer relaxation. The best formulations were found to be stable during stability studies for one month.Thus, best formulations satisfied physico-chemical parameters, floating time, swelling index and in vitrodrug release profile requirements for a floating drug delivery system.

  14. Multi-input and binary reproducible, high bandwidth floating point adder in a collective network

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dong; Eisley, Noel A; Heidelberger, Philip; Steinmacher-Burow, Burkhard

    2015-03-10

    To add floating point numbers in a parallel computing system, a collective logic device receives the floating point numbers from computing nodes. The collective logic devices converts the floating point numbers to integer numbers. The collective logic device adds the integer numbers and generating a summation of the integer numbers. The collective logic device converts the summation to a floating point number. The collective logic device performs the receiving, the converting the floating point numbers, the adding, the generating and the converting the summation in one pass. One pass indicates that the computing nodes send inputs only once to the collective logic device and receive outputs only once from the collective logic device.

  15. Multi-input and binary reproducible, high bandwidth floating point adder in a collective network

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dong; Eisley, Noel A.; Heidelberger, Philip; Steinmacher-Burow, Burkhard

    2016-11-15

    To add floating point numbers in a parallel computing system, a collective logic device receives the floating point numbers from computing nodes. The collective logic devices converts the floating point numbers to integer numbers. The collective logic device adds the integer numbers and generating a summation of the integer numbers. The collective logic device converts the summation to a floating point number. The collective logic device performs the receiving, the converting the floating point numbers, the adding, the generating and the converting the summation in one pass. One pass indicates that the computing nodes send inputs only once to the collective logic device and receive outputs only once from the collective logic device.

  16. 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.

  17. 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.

    in the East Sea and the Indian Ocean, it is found that there a systematic drift in the older float compared to later deployments. All drift results, consistently show negative bias indicating the typical nature of drift from fouled sensors. However, the drift...

  18. Differential multiple-time-programmable memory cells by laterally coupled floating metal gate fin field-effect transistors

    Science.gov (United States)

    Hsu, Chia-Ling; Liao, Chu-Feng; Chien, Wei Yu; Chih, Yue-Der; Lin, Chrong Jung; King, Ya-Chin

    2017-04-01

    In this paper, we present a new differential multiple-time-programmable (MTP) memory cell with a novel slot contact coupling structure in the fin field-effect transistor (FinFET) CMOS process. This MTP cell contains a pair of floating metal gates to store differential data on a single cell. Through differential read operations, the cells are less susceptible to read error caused by cell-to-cell variations. In a nano-scaled FinFET process, the gate dielectric layer becomes too thin to retain charge in the floating gates for long periods of time. Differential cell design further extends the data lifetime, even with the serious charge-loss problem, and reduces the overall intellectual property (IP) area.

  19. Development of a Semi-submersible Barge for the installation of a TLP floating substructure. TLPWIND® case study

    Science.gov (United States)

    Amate, Juan; Sánchez, Gustavo D.; González, Gonzalo

    2016-09-01

    One of the biggest challenges to introduce Tension Leg Platform (TLP) technology into the Offshore Wind market are the Transport & Installation (T&I) stages, since most of TLPs are not self-stable as semisubmersible or SPAR platforms, and consequently requires additional means to perform these operations. This paper addresses this problem that has been overcome through the development of a Semi-submersible “Transport & Installation” Barge (SSB) for Iberdrola's TLPWIND® floating support structure. The Semi-submersible Barge has been designed both through the use of numerical models and an extensive basin testing campaign carried out at the University of Strathclyde facilities. This paper also includes an estimation of the duration in time to carry out the installation process of a Floating Offshore Wind Farm, comprising 100x5MW TLPWIND® units in different scenarios.

  20. 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.

  1. Phyllosphere bacterial community of floating macrophytes in paddy soil environments as revealed by illumina high-throughput sequencing.

    Science.gov (United States)

    Xie, Wan-Ying; Su, Jian-Qiang; Zhu, Yong-Guan

    2015-01-01

    The phyllosphere of floating macrophytes in paddy soil ecosystems, a unique habitat, may support large microbial communities but remains largely unknown. We took Wolffia australiana as a representative floating plant and investigated its phyllosphere bacterial community and the underlying driving forces of community modulation in paddy soil ecosystems using Illumina HiSeq 2000 platform-based 16S rRNA gene sequence analysis. The results showed that the phyllosphere of W. australiana harbored considerably rich communities of bacteria, with Proteobacteria and Bacteroidetes as the predominant phyla. The core microbiome in the phyllosphere contained genera such as Acidovorax, Asticcacaulis, Methylibium, and Methylophilus. Complexity of the phyllosphere bacterial communities in terms of class number and α-diversity was reduced compared to those in corresponding water and soil. Furthermore, the bacterial communities exhibited structures significantly different from those in water and soil. These findings and the following redundancy analysis (RDA) suggest that species sorting played an important role in the recruitment of bacterial species in the phyllosphere. The compositional structures of the phyllosphere bacterial communities were modulated predominantly by water physicochemical properties, while the initial soil bacterial communities had limited impact. Taken together, the findings from this study reveal the diversity and uniqueness of the phyllosphere bacterial communities associated with the floating macrophytes in paddy soil environments.

  2. 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.

  3. 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.

  4. 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.

  5. Numerical study on aerodynamic damping of floating vertical axis wind turbines

    DEFF Research Database (Denmark)

    Cheng, Zhengshun; Aagaard Madsen, Helge; Gao, Zhen;

    2016-01-01

    Harvesting offshore wind energy resources using floating vertical axis wind turbines (VAWTs) has attracted an increasing interest in recent years. Due to its potential impact on fatigue damage, the aerodynamic damping should be considered in the preliminary design of a floating VAWT based...... on the frequency domain method. However, currently the study on aerodynamic damping of floating VAWTs is very limited. Due to the essential difference in aerodynamic load characteristics, the aerodynamic damping of a floating VAWT could be different from that of a floating horizontal axis wind turbine (HAWT......). In this study, the aerodynamic damping of floating VAWTs was studied in a fully coupled manner, and its influential factors and its effects on the motions, especially the pitch motion, were demonstrated. Three straight-bladed floating VAWTs with identical solidity and with a blade number varying from two...

  6. 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.

  7. 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.

  8. On the onset of multi-wave patterns in laterally heated floating zones for slightly supercritical conditions

    Science.gov (United States)

    Lappa, Marcello

    2016-12-01

    This analysis follows and integrates the line of inquiry started in past author's works [M. Lappa, "Three-dimensional numerical simulation of Marangoni flow instabilities in floating zones laterally heated by an equatorial ring," Phys. Fluids 15(3), 776-789 (2003) and "Combined effect of volume and gravity on the three-dimensional flow instability in non-cylindrical floating zones heated by an equatorial ring," ibid. 16(2), 331-343 (2004)] about the typical instabilities of the Marangoni flow and associated hierarchy of bifurcations in laterally heated floating zones with various shapes and aspect ratios. The main motivation for re-examining this kind of problems, which have attracted so much attention over the last twenty years, is the recent discovery [M. Kudo et al., "Transition of thermocapillary convection in a full-zone liquid bridge," Trans. JSME (in Japanese) 80(812), TEP0095 (2014)] of a chaotic state in the region of the space of parameters where on the basis of existing theories and earlier results for the classical liquid-bridge problem with organic fluids, the flow should be relatively regular in time and with a simple structure in space. Axisymmetric computations are used to obtain the steady basic state, and then the Navier Stokes equations are solved in their complete, three-dimensional, time-dependent, and non-linear formulation to investigate the evolution of azimuthal disturbances. It is shown that the "apparent" doubling or quadrupling of the azimuthal wavenumber in the equatorial plane, previously reported for the case of floating zones of liquid metals, is replaced for high-Prandtl-number liquids by the complex interaction of disturbances with distinct spatial and temporal scales. These disturbances become critical at relatively comparable values of the Marangoni number. The unexpected multiplicity of waveforms and competition of spatial modes are explained according to the increased complexity of the considered system in terms of flow

  9. Analyses and thought on countermeasures for the family formation trend among floating population in Wuhan city.

    Science.gov (United States)

    Chen, X; Sun, L

    1997-01-01

    The familized floating population in China consists of families formed from blood kinship networks of floating population. This study examines the size of the familized floating population in Wuhan City in 1995 and the negative impacts for urban management, supplies, family planning, education, and employment. Floating population families are formed due to the presence of rural and urban differences, the desire for income, and a goal of permanent urban residence with family stability and steady economic gains. Data were obtained from a 1% sample survey among the floating population who lived in rented, borrowed, or self-built houses or apartments for over 6 months. 69.2% of the floating population, or 335,000 people, were familized floating population. 55.01% of the familized floating population were women, and 60.41% of the laborers were women. 33.50% of the women who "should" be employed were not. 50% of the women in some districts were unemployed. 30.61% were children under 14 years of age. The dependency burden for the employed floating population was greater than for the urban employed population. The birth rate among the familized floating population was 44.60%. 89.59% of women aged older than 15 years in the familized floating population were of childbearing age. Most had a low level of education. The floating population creates the need for educating 15,000 new students every year; this requires construction of 10 new schools every year. The floating population increases the need to produce more electricity, clothing, food, houses, and other services or facilities. The floating population brings norms about a higher family size, which challenges urban residents' beliefs and impedes smooth implementation of the family planning policy. Management needs to regulate population flow, reduce consumption, and control family formation and childbearing. Management needs to increase mobility costs.

  10. Floating Technology Study of a New Large Calibre Machine Gun%某新型大口径机枪浮动技术研究

    Institute of Scientific and Technical Information of China (English)

    范智滕; 王瑞林; 康小勇; 田昊; 胡尚夫

    2014-01-01

    为研究大口径机枪的浮动技术,在深入分析的基础上针对某新型大口径机枪,设计方便可行且结构合理的弹簧式浮动机构。通过设置独特的复进打断装置,实现了浮动过程中稳定的前冲击发。建立机枪枪身的虚拟样机模型,通过与试验结果进行对比,验证了其可信性。利用所建立的虚拟样机模型对浮动与不浮动状态下的浮动自动机进行运动分析,并对2种状态下的后坐力进行对比。结果表明,该机枪浮动自动机能实现稳定的浮动,并且减后坐力效果明显。%To study the floating technology of a large-caliber machine gun,through analyzing the structure of a new large caliber machine gun,a convenient,practicable and reasonably-structured spring-type floating mechanism was designed.The installation of a unique counter-recoil interrupting device achieves stable advance firing in the floating process.A virtual prototype model of the machine gun was established.Through comparing with test results,the model was proved to be credible.By using the virtual prototype model,the movement of the floating automatic mechanism was studied in both the floating and non-floating states,and the recoil force of the two states was compared.The results indicate that the floating automatic mechanism of the machine gun can achieve steady floating,and significantly reduce the recoil force.

  11. A survey of floating population in 50 townships in China.

    Science.gov (United States)

    Zhang, Q

    1995-01-01

    This article presents the findings from the survey of the floating population in China. The survey was conducted in 1991 among 58 townships in 20 provinces after a pilot survey was carried out in Sanhe County of Hebei Province and Wutai County of Shanxi Province. Townships were selected that were representative of the situations in their province. The final sample included only 50 townships due to poor quality data. The population in the sample townships included 18,926 immigrants, or 22.5% of total population, and 9,678 emigrants, or 11.6% of total population. Among seven suburban townships the immigration rate was 44.9% and the emigration rate was 3.2%. Eight coastal townships had an immigrant population of 24.9% and an emigrant population of 3.9%. Inland townships (35) had an immigration rate of 13.9% and emigration rate of 16.5%. Inland migrants moved to places with better economic conditions. 67.4% of the total floating population was male, and 32.6% was female. 4.88% were aged under 14 years and 1.64% were aged over 60 years. 73.4% were aged 15-29 years. 52.7% of the floating population had a junior high education and 32.1% had an elementary school education. The floating population comprised a high proportion of unmarried persons. Most shifted their occupations from the agricultural to the nonagricultural sector. 84.7% of the floating population lived in suburbs, and many worked as vendors, handicraft workers, and sanitation workers. In coastal areas, most were employed in industries and lived in company dorms or rented houses. The average income was RMB1373. Average household income was RMB347 more than the amount for rural residents. Coastal income was higher. 61% worked in services, construction, and transportation. 16% worked in commerce. 23% were visitors. The author states that the floating population is a product of a large and growing rural labor surplus.

  12. 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.

  13. 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.

  14. Study on electrical power output of floating photovoltaic and conventional photovoltaic

    Science.gov (United States)

    Azmi, Mohd Syahriman Mohd; Othman, Mohd Yusof Hj.; Ruslan, Mohd Hafidz Hj.; Sopian, Kamaruzzaman; Majid, Zafri Azran Abdul

    2013-11-01

    In this paper, several attempt were made to investigate the best electrical performance of a floating photovoltaic (FPV). In photovoltaic (PV) system, the electrical efficiency of the system decreases rapidly as the PV module temperature increases. Therefore, in order to achieve higher electrical efficiency, the PV module have to be cooled by removing the heat in some way. This paper presents study on a conventional photovoltaic (PV) module and floating photovoltaic (FPV) system. The objective of the study is to compare the performance of conventional PV module and FPV. At FPV, an absorber comprises of aluminum flat-box housing was attached to the back of the PV module to absorb heat. Water is used to cool the PV module by passing it under the bottom surface of the module. The system was tested under simulated solar intensity of 417 W/m2, 667 W/m2 and 834 W/m2. Current (I) - voltage (V) curves and power (P) - voltage (V) curves of the results were analyzed. The study found that the FPV has higher efficiency and total power gain than the conventional PV module. The average PV temperature in a FPV might be lower than that for a conventional PV module, thereby increasing its electrical power output. The simplicity of the system structure and aluminum as the chosen material enabled it to reduce the installation costs for a larger scale. Applicable as heat sink, this FPV system is convenient to place on lakes, ponds or rivers.

  15. 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.

  16. 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.

  17. 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...

  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

    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 use of both......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...

  19. The 5 MW DeepWind floating offshore vertical wind turbine concept design - status and perspective

    DEFF Research Database (Denmark)

    Schmidt Paulsen, Uwe; Aagaard Madsen, Helge; Kragh, Knud Abildgaard

    2014-01-01

    Floating vertical-axis wind turbines for offshore wind energy present a concept with novelty and potentials for reducing COE. Cost reduction for offshore wind power plants is an industrial challenge, and DeepWind is - as the analysis of the current design shows-believed to be a good candidate...... in achieving this. In the paper the current design status of the 5 MW DeepWind concept is presented. The intended siting for the turbine is off the Norwegian west coast at about 250 m of sea depth. Focus is set on the integrated design highlighting structural benefits of the light rotor, the hydrodynamic...... in generator design. The paper presents new developments in the current design of a novel rotor shape with overspeed control. Rotor performance, design structural key figures and upscaling potential are reported. New results implemented on permanent magnets generator and - bearing technology show...

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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%.

  7. Extra-long Float-zones Induced by Thermocapillary Flows

    Science.gov (United States)

    Chen, Yi-Ju; Steen, Paul H.

    1996-11-01

    A model problem is posed to study the influence of flow on the interfacial stability of a nearly cylindrical liquid bridge for lengths near its circumference (the Plateau-Rayleigh limit). Zero gravity is assumed. The flow is generated by a shear stress imposed on the deformable interface. The symmetry of the imposed stress mimics the thermocapillary effect induced on a float-zone by a ring heater (i.e. a full zone). Numerical solutions, complemented by a bifurcation analysis, show that bridges substantially longer than the Plateau-Rayleigh limit are possible. An interaction of the first two capillary instabilities through the stress-induced pressure gradient is responsible. Time-periodic standing waves are also predicted in certain parameter ranges. Motivation comes from extra-long float-zones observed in MEPHISTO space lab experiments (June 1994).

  8. Voltage controlled resistor using quasi-floating-gate MOSFETs

    Directory of Open Access Journals (Sweden)

    Susheel Sharma

    2013-01-01

    Full Text Available A voltage controlled resistor (VCR using quasi-floating-gate MOSFETs (QFGMOS suitable for low voltage applications is presented. The performance of the VCR implemented with QFGMOS is compared with its floating-gate MOSFET (FGMOS version. It was found that QFGMOS offers better performance than FGMOS in terms of frequency response, offsets and chip area. The VCR using QFGMOS offers high bandwidth and low power dissipation and yields high value of resistance as compared to its FGMOS counterpart. The workability of the presented circuits was tested by PSpice simulations using level 3 parameters of 0.5μm CMOS technology with supply voltage of ± 0.75V. The simulations results were found to be in accordance with the theoretical predictions.

  9. Interval Semantics for Standard Floating-Point Arithmetic

    CERN Document Server

    Edmonson, W W

    2008-01-01

    If the non-zero finite floating-point numbers are interpreted as point intervals, then the effect of rounding can be interpreted as computing one of the bounds of the result according to interval arithmetic. We give an interval interpretation for the signed zeros and infinities, so that the undefined operations 0*inf, inf - inf, inf/inf, and 0/0 become defined. In this way no operation remains that gives rise to an error condition. Mathematically questionable features of the floating-point standard become well-defined sets of reals. Interval semantics provides a basis for the verification of numerical algorithms. We derive the results of the newly defined operations and consider the implications for hardware implementation.

  10. 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.

  11. Floating Marine Debris in waters of the Mexican Central Pacific.

    Science.gov (United States)

    Díaz-Torres, Evelyn R; Ortega-Ortiz, Christian D; Silva-Iñiguez, Lidia; Nene-Preciado, Alejandro; Orozco, Ernesto Torres

    2017-02-15

    The presence of marine debris has been reported recently in several oceans basins; there is very little information available for Mexican Pacific coasts, however. This research examined the composition, possible sources, distribution, and density of Floating Marine Debris (FMD) during nine research surveys conducted during 2010-2012 in the Mexican Central Pacific (MCP). Of 1820 floating objects recorded, 80% were plastic items. Sources of FMD were determined using key objects, which indicated that the most were related to the presence of the industrial harbor and of a growing fishing industry in the study area. Densities were relatively high, ranging from 40 to 2440objects/km(2); the highest densities were recorded in autumn. FMD were distributed near coastal regions, mainly in Jalisco, influenced by river outflow and surface currents. Our results seem to follow worldwide trends and highlight the need for further studies on potential ecological impacts within coastal waters of the MCP.

  12. 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.

  13. A REVIEW ON FLOATING TYPE GASTRORETENTIVE DRUG DELIVERY SYSTEM

    Directory of Open Access Journals (Sweden)

    Pallavi Pal

    2012-04-01

    Full Text Available 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 particular site and controlling the release of drug especially useful for achieving controlled plasma level a swell as improving bioavailability Several approaches are currently being used to prolong the GRT, including floating drug delivery systems (FDDS, also known as hydrodynamically balanced systems (HBS, swelling and expanding systems, high-density systems, and other delayed gastric emptying devices.

  14. Mature ovarian teratoma with large floating fat globules

    Energy Technology Data Exchange (ETDEWEB)

    Son, Hye Min; Kim, See Hyung; Hwang, Il Seon [Keimyung University School of Medicine, Dongsan Medical Center, Daegu (Korea, Republic of)

    2016-04-15

    Mature ovarian teratoma (dermoid cyst), a germ cell neoplasm, is one of the most common ovarian tumors. It is composed of derivatives of three germ cell layers. A mature ovarian teratoma with intracystic fat globules is rare. The pathogenesis on the formation of fat globules is unclear. Here we present a pathologically proven cystic ovarian teratoma with three large floating fat globules in a young woman with CT and MR findings.

  15. Formulation and characterization of rifabutin loaded floating gellan gum beads

    OpenAIRE

    2011-01-01

    Rifabutin loaded floating gellan gum beads were prepared by Ca++ induced ionotropic gelation in acidic medium by drop wise addition of gellan gum dispersion containing drug and gas-generating agent. The prepared beads were evaluated for in vitro characterization and in vivo Helicobacter pylori clearance efficiency following repeated oral administration to H. pylori infected albino rats. Live cell staining of stomach homogenates of H. pylori infected animals treated with rifabutin showed prono...

  16. Computing Integer Powers in Floating-Point Arithmetic

    CERN Document Server

    Kornerup, Peter; Muller, Jean-Michel

    2007-01-01

    We introduce two algorithms for accurately evaluating powers to a positive integer in floating-point arithmetic, assuming a fused multiply-add (fma) instruction is available. We show that our log-time algorithm always produce faithfully-rounded results, discuss the possibility of getting correctly rounded results, and show that results correctly rounded in double precision can be obtained if extended-precision is available with the possibility to round into double precision (with a single rounding).

  17. Computing Integer Powers in Floating-Point Arithmetic

    OpenAIRE

    Kornerup, Peter; Lefèvre, Vincent; Muller, Jean-Michel

    2007-01-01

    We introduce two algorithms for accurately evaluating powers to a positive integer in floating-point arithmetic, assuming a fused multiply-add (fma) instruction is available. We show that our log-time algorithm always produce faithfully-rounded results, discuss the possibility of getting correctly rounded results, and show that results correctly rounded in double precision can be obtained if extended-precision is available with the possibility to round into double precision (with a single rou...

  18. Floating-point array processors evolve into tailorable systems

    Energy Technology Data Exchange (ETDEWEB)

    Kotelly, G.

    1983-05-12

    Recently introduced 32-bit floating point array processors (APs) combine configuration flexibility, integrated hardware/software system architecture and real-time computational power to meet a variety of application requirements. APS have now evolved into general-purpose boxes and PC boards which readily adapt to changing OEM needs. Contributing to this greater AP versatility are a variety of hardware and software features. These features are described and the range of available products is surveyed.

  19. Rice cultivation on floating-beds in different natural waters

    Institute of Scientific and Technical Information of China (English)

    SONGXiangfu; WUWeiming; JINGQianyu; YINGHuodong; ZHUMing; ZOUGuoyan

    1997-01-01

    Following the success in rice cultivation on floating-beds in natural water in 1990, the ecological adaptability of growing rice on floatingbeds was studied during the period of 1991-1993. Experiments were conducted in five different types of natural waters in Zhejiang Province from 28°35′ to 30°58′N and from 119°05′ to 121°11′E.

  20. 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.

  1. Floating Ice-Algal Aggregates below melting Arctic Sea Ice

    OpenAIRE

    Philipp Assmy; Jens K. Ehn; Mar Fernández-Méndez; Haakon Hop; Christian Katlein; Arild Sundfjord; Katrin Bluhm; Malin Daase; Anja Engel; Agneta Fransson; Granskog, Mats A.; Hudson, Stephen R.; Svein Kristiansen; Marcel Nicolaus; Ilka Peeken

    2013-01-01

    During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates in the melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1 – 15 cm in diameter) aggregates had a mucous consistency and were dominated by typical ice-associated pennate diatoms embedded within the mucous matrix. Aggregates maintained buoyancy and accumulated just above a strong pycnocline that separated meltwater and seawater layer...

  2. A big floating thrombus in the common carotid artery.

    Science.gov (United States)

    La Spada, Michele; Stilo, Francesco; Barillà, David; Spinelli, Francesco

    2011-11-01

    The management of the free-floating thrombus (FFT) is difficult, and it is unclear whether surgical or medical treatment is superior. The common carotid artery is rarely involved. An 80-year-old woman presented with right hand weakness and syncope. Ultrasound showed the presence of FFT in the left common carotid artery. A carotid endarterectomy with Dacron patch angioplasty was immediately performed without complications. In the presence of symptoms, the interventional management of FFT is advised.

  3. A floating macro/mesoporous crystalline anatase TiO2 ceramic with enhanced photocatalytic performance for recalcitrant wastewater degradation.

    Science.gov (United States)

    Xing, Zipeng; Zhou, Wei; Du, Fan; Qu, Yang; Tian, Guohui; Pan, Kai; Tian, Chungui; Fu, Honggang

    2014-01-14

    A macro/mesoporous anatase TiO2 ceramic floating photocatalyst has been successfully synthesized using highly thermally stable mesoporous TiO2 powder as a precursor, followed by a camphene-based freeze-casting process and high-temperature calcinations. The ceramics are characterized in detail by X-ray diffraction, Raman spectra, scanning electron microscopy, transmission electron microscopy and N2 adsorption-desorption isotherms. The results indicate that the TiO2 ceramics present hierarchical macro/mesoporous structures, which maintain high porosity and high compressive strength at the optimal sintering temperature of 800 °C. The ordered mesoporous TiO2 network still possesses high thermal stability and inhibits the anatase-to-rutile phase transformation during calcinations. The obtained ceramics exhibit good adsorptive and photocatalytic activity for the degradation of octane and rhodamine B, and the total organic carbon removal ratio is up to 98.8% and 98.6% after photodegradation for 3 h, respectively. The roles of active species in the photocatalytic process are compared using different types of active species scavengers, and the degradation mechanism is also proposed. Furthermore, the ceramics are recyclable, and no clear changes are observed after ten cycles. In addition, the ceramics are also active in the photodegradation of phenol, thiobencarb, and atrazine. Therefore, these novel floating photocatalysts will have wide applications, including the removal of floating organic pollutants from the wastewater surfaces or the removal of soluble organic pollutants from wastewater.

  4. Modeling and discussion of threshold voltage for a multi-floating gate FET pH sensor

    Institute of Scientific and Technical Information of China (English)

    Shi Zhaoxia; Zhu Dazhong

    2009-01-01

    Research into new pH sensors fabricated by the standard CMOS process is currently a hot topic. The new pH sensing multi-floating gate field effect transistor is found to have a very large threshold voltage, which is different from the normal ion-sensitive field effect transistor. After analyzing all the interface layers of the structure, a new sensitive model based on the Gauss theorem and the charge neutrality principle is created in this paper. According to the model, the charge trapped on the multi-floating gate during the process and the thickness of the sensitive layer are the main causes of the large threshold voltage. From this model, it is also found that removing the charge on the multi-floating gate is an effective way to decrease the threshold voltage. The test results for three different standard pH buffer solutions show the correctness of the model and point the way to solve the large threshold problem.

  5. Efficient floating diffuse functions for accurate characterization of the surface-bound excess electrons in water cluster anions.

    Science.gov (United States)

    Zhang, Changzhe; Bu, Yuxiang

    2017-01-25

    In this work, the effect of diffuse function types (atom-centered diffuse functions versus floating functions and s-type versus p-type diffuse functions) on the structures and properties of three representative water cluster anions featuring a surface-bound excess electron is studied and we find that an effective combination of such two kinds of diffuse functions can not only reduce the computational cost but also, most importantly, considerably improve the accuracy of results and even avoid incorrect predictions of spectra and the EE shape. Our results indicate that (a) simple augmentation of atom-centered diffuse functions is beneficial for the vertical detachment energy convergence, but it leads to very poor descriptions for the singly occupied molecular orbital (SOMO) and lowest unoccupied molecular orbital (LUMO) distributions of the water cluster anions featuring a surface-bound excess electron and thus a significant ultraviolet spectrum redshift; (b) the ghost-atom-based floating diffuse functions can not only contribute to accurate electronic calculations of the ground state but also avoid poor and even incorrect descriptions of the SOMO and the LUMO induced by excessive augmentation of atom-centered diffuse functions; (c) the floating functions can be realized by ghost atoms and their positions could be determined through an optimization routine along the dipole moment vector direction. In addition, both the s- and p-type floating functions are necessary to supplement in the basis set which are responsible for the ground (s-type character) and excited (p-type character) states of the surface-bound excess electron, respectively. The exponents of the diffuse functions should also be determined to make the diffuse functions cover the main region of the excess electron distribution. Note that excessive augmentation of such diffuse functions is redundant and even can lead to unreasonable LUMO characteristics.

  6. Floating type ocean wave power station equipped with hydroelectric unit

    Science.gov (United States)

    Okamoto, Shun; Kanemoto, Toshiaki; Umekage, Toshihiko

    2013-10-01

    The authors have invented the unique ocean wave power station, which is composed of the floating type platform with a pair of the floats lining up at the interval of one wave pitch and the counter-rotating type wave power unit, its runners are submerged in the seawater at the middle position of the platform. Such profiles make the flow velocity at the runner is twice faster than that of the traditional fixed/caisson type OWC, on the ideal flow conditions. Besides, the runners counter-rotate the inner and the outer armatures of the peculiar generator, respectively, and the relative rotational speed is also twice faster than the speed of the single runner/armature. Such characteristics make the runner diameter large, namely the output higher, as requested, because the torque of the power unit never act on the floating type platform. At the preliminary reseach, this paper verifies to get the power using a Wells type single runner installed in the model station. The runner takes the output which is affected by the oscillating amplitude of the platform, the rotational speed and the inertia force of the runner, etc.

  7. 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.

  8. 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.

  9. Floating microparticles based on low density foam powder.

    Science.gov (United States)

    Streubel, A; Siepmann, J; Bodmeier, R

    2002-07-25

    The aim of this study was to develop a novel multiparticulate gastroretentive drug delivery system and to demonstrate its performance in vitro. Floating microparticles consisting of (i) polypropylene foam powder; (ii) verapamil HCl as model drug; and (iii) Eudragit RS, ethylcellulose (EC) or polymethyl methacrylate (PMMA) as polymers were prepared with an O/W solvent evaporation method. The effect of various formulation and processing parameters on the internal and external particle morphology, drug loading, in vitro floating behavior, in vitro drug release kinetics, particle size distribution and physical state of the incorporated drug was studied. The microparticles were irregular in shape and highly porous. The drug encapsulation efficiency was high and almost independent of the theoretical loading. Encapsulation efficiencies close to 100% could be achieved by varying either the ratio 'amount of ingredients: volume of the organic phase' or the relative amount of polymer. In all cases, good in vitro floating behavior was observed. The release rate increased with increasing drug loading and with decreasing polymer amounts. The type of polymer significantly affected the drug release rate, which increased in the following rank order: PMMA

  10. Temporal and Spatial Changes in Northern Hemisphere Floating Climatological Seasons

    Science.gov (United States)

    Choi, G.; Robinson, D. A.

    2007-12-01

    Floating climatological seasons, for which onsets and durations vary temporally and spatially, are examined over Northern Hemisphere continents and oceans. Among the variables evaluated are surface air temperature, snow extent, vegetation greenness, and atmospheric carbon dioxide concentrations. Seasonal thresholds are defined for each variable (e.g. daily mean temperature exceeding 5°C (20°C) to mark the beginning of spring (summer)). The dates on which these thresholds are reached at a given location are determined for each year over the past three decades. These seasonal onsets and offsets "float" temporally and spatially from year to another. An analysis of floating dates finds that winter duration has shortened in Europe, eastern Asia, and western North America, primarily due to an earlier spring onset. The spatial pattern of this earlier onset is associated with a positive Arctic Oscillation (AO) regime in the previous winter months. The positive winter AO finds anomalously high pressure sitting in the middle latitudes in locations where spring arrives early. This is likely due to a combination of advective fluxes of warmth and moisture and the local enhancement of solar radiation reaching the surface under clear skies. This, in turn, promotes earlier snow melt that further enhances warming and an earlier green-up. Extended summer duration is observed over continents and oceans (except the Arctic Ocean, where summer does not exist). The oceanic zone along 30°N has experienced a particularly large increase in duration, suggesting Hadley cell expansion.

  11. Formulation and evaluation of floating matrix tablets of diltiazem hydrochloride

    Directory of Open Access Journals (Sweden)

    Vinay D Gaikwad

    2012-01-01

    Full Text Available This study was performed to design floating tablets of diltiazem as a model drug for prolongation of gastric residence time. A simple visible spectrophotometric method was employed for the estimation of diltiazem at 236 nm and Beer′s law is obeyed in the concentration range of 2-20 mg/ml. Preformulation studies were carried out to optimize the ratios required for various grades of HPMC-SCMC and HPMC- Carbopol P934. Total 10 formulations (five each were prepared using HPMC (K4M. The prepared floating tablets were evaluated for hardness, weight variation, thickness, friability, drug content uniformity, buoyancy lag time, total floating time, water uptake (swelling index, and in vitro dissolution studies. SEM and stability studies were carried out only for best release formulations (A1 and B1. Among the five formulations with HPMC K4M and A1-A4 showed drug release ranging from 99.89 to 77.52%. Similarly five formulations with HPMC K4M and Carbopol P934 (B1-B4 showed drug release ranging from 97.9 to 80.35% in 0.1 N HCl dissolution medium. Formulations A1 and B1 gave maximum drug release upto 100% within 12 hrs. SEM for A1 and B1 formulations revealed that surface was smooth upto 4 hrs after that swelling and porosity of tablet increased indicating the diffusion and erosion mechanism of release.

  12. Floating-to-Fixed-Point Conversion for Digital Signal Processors

    Directory of Open Access Journals (Sweden)

    Menard Daniel

    2006-01-01

    Full Text Available Digital signal processing applications are specified with floating-point data types but they are usually implemented in embedded systems with fixed-point arithmetic to minimise cost and power consumption. Thus, methodologies which establish automatically the fixed-point specification are required to reduce the application time-to-market. In this paper, a new methodology for the floating-to-fixed point conversion is proposed for software implementations. The aim of our approach is to determine the fixed-point specification which minimises the code execution time for a given accuracy constraint. Compared to previous methodologies, our approach takes into account the DSP architecture to optimise the fixed-point formats and the floating-to-fixed-point conversion process is coupled with the code generation process. The fixed-point data types and the position of the scaling operations are optimised to reduce the code execution time. To evaluate the fixed-point computation accuracy, an analytical approach is used to reduce the optimisation time compared to the existing methods based on simulation. The methodology stages are described and several experiment results are presented to underline the efficiency of this approach.

  13. Floating ice-algal aggregates below melting arctic sea ice.

    Science.gov (United States)

    Assmy, Philipp; Ehn, Jens K; Fernández-Méndez, Mar; Hop, Haakon; Katlein, Christian; Sundfjord, Arild; Bluhm, Katrin; Daase, Malin; Engel, Anja; Fransson, Agneta; Granskog, Mats A; Hudson, Stephen R; Kristiansen, Svein; Nicolaus, Marcel; Peeken, Ilka; Renner, Angelika H H; Spreen, Gunnar; Tatarek, Agnieszka; Wiktor, Jozef

    2013-01-01

    During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates in the melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm in diameter) aggregates had a mucous consistency and were dominated by typical ice-associated pennate diatoms embedded within the mucous matrix. Aggregates maintained buoyancy and accumulated just above a strong pycnocline that separated meltwater and seawater layers. We were able, for the first time, to obtain quantitative abundance and biomass estimates of these aggregates. Although their biomass and production on a square metre basis was small compared to ice-algal blooms, the floating ice-algal aggregates supported high levels of biological activity on the scale of the individual aggregate. In addition they constituted a food source for the ice-associated fauna as revealed by pigments indicative of zooplankton grazing, high abundance of naked ciliates, and ice amphipods associated with them. During the Arctic melt season, these floating aggregates likely play an important ecological role in an otherwise impoverished near-surface sea ice environment. Our findings provide important observations and measurements of a unique aggregate-based habitat during the 2012 record sea ice minimum year.

  14. 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.

  15. Redox dynamics in multicomponent, iron-bearing silicate melts and glasses: Application to the float-glass processing of high-temperature silicate glassmelts

    Science.gov (United States)

    Cook, Glen Bennett

    glassmelt. Based on this finding, combined with the substantial database on conventional float glass, a kinetic model for the reaction is presented. The metal/silicate couples are well characterized as a cation-diffusion rate-limited reaction of serial steps that include two structural reactions in the interior of the glassmelt: one involving oxidation of the incorporated (i.e., from the float alloy) cation from the divalent to tetravalent state and the second (related) involving the reduction of Fesp{3+} to Fesp{2+}.

  16. Conceptual Design of Navy Floating Pier.

    Science.gov (United States)

    1982-09-01

    in. A single point mooring system permanently anchors the structure. In 1981, a smaller concrete barge was built In Singapore and towed to Mexico . The...Ul CMINC-$ zee :;7 ,s: S. 1,- -1- 1f No. tONON6 100-14-- &. - I.Z3 Firf A ~~ (Z4.00),.14M - ro*ax % rp z o3- r-z N~~~I- T=1,06- -4z -5 F -’-’TWWCTUIEA L

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

    Directory of Open Access Journals (Sweden)

    Sukhvir Kaur

    2013-06-01

    Full Text Available 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 important concern. Until now there is the implementation of the low precision floating point formats, but this piece of work considers the implementation of 64-bit double precision multiplier. This paper presents the FPGA implementation of double precision floating point multiplier using Xilinx Coregen Tool.

  18. Memory operations in Au nanoparticle single-electron transistors with floating gate electrodes

    Science.gov (United States)

    Azuma, Yasuo; Sakamoto, Masanori; Teranishi, Toshiharu; Majima, Yutaka

    2016-11-01

    Floating gate memory operations are demonstrated in a single-electron transistor (SET) fabricated by a chemical assembly using the Au nanogap electrodes and the chemisorbed Au nanoparticles. By applying pulse voltages to the control gate, phase shifts were clearly and stably observed both in the Coulomb oscillations and in the Coulomb diamonds. Writing and erasing operations on the floating gate memory were reproducibly observed, and the charges on the floating gate electrodes were maintained for at least 12 h. By considering the capacitance of the floating gate electrode, the number of electrons in the floating gate electrode was estimated as 260. Owing to the stability of the fabricated SET, these writing and erasing operations on the floating gate memory can be applied to reconfigurable SET circuits fabricated by a chemically assembled technique.

  19. Design of a Floating-Point Fused Add-Subtract Unit Using Verilog

    Directory of Open Access Journals (Sweden)

    Mayank Sharma,

    2013-06-01

    Full Text Available A floating-point (FP fused add-subtract unit is presented that performs simultaneous floating-point operation of add-subtract on a common pair of single-precision data at the same time that it takes to perform in a single addition with a conventional floating-point adder. The system was placed and routed in 45nm process so that there will be less consumption of memory as well as power.

  20. Technology Development and Circuit Design for a Parallel Laser Programmable Floating Point Application Specific Processor

    Science.gov (United States)

    1989-12-01

    The laser programmable floating point application specific processor (LPASP) is a new approach at rapid development of custom VLSI chips. The LPASP...double precision floating point adder and the laser programmable read-only memory (LPROM) that are macrocells within the LPASP. In addition, the...thesis analyzes the applicability of an LPASP parallel processing system. The double precision floating point adder is an adder/subtractor macrocell

  1. The Unum Number Format: Mathematical Foundations, Implementation and Comparison to IEEE 754 Floating-Point Numbers

    OpenAIRE

    Hunhold, Laslo

    2017-01-01

    This thesis examines a modern concept for machine numbers based on interval arithmetic called 'Unums' and compares it to IEEE 754 floating-point arithmetic, evaluating possible uses of this format where floating-point numbers are inadequate. In the course of this examination, this thesis builds theoretical foundations for IEEE 754 floating-point numbers, interval arithmetic based on the projectively extended real numbers and Unums.

  2. 海上风力发电浮式基础的研究进展及关键技术问题%Research Development and Key Technical on Floating Foundation for Offshore Wind Turbines

    Institute of Scientific and Technical Information of China (English)

    胡军; 唐友刚; 阮胜福

    2012-01-01

    The water area that water depth is deeper than 50m,has special advantage in wind turbine generating because there are the stable wind speed and small Wind-shear.In such sea area,the offshore wind energy generating equipments should setup on floating foundation structure.Therefore,it is of great significance to study the floating foundation structures that are available for offshore wind energy generating for the industrialization of the offshore wind power generation.The basic type and working principles are studied for some novel floating structures in recent year.So,to research the some key technical problems and risk factors of the floating structure or working load caused by turbine running and seas environment loads of floating structure are valuable for designing the floating structures of wind turbine generating.%水深大于50m的海域,风速稳定、风切变小,具有风力发电的独特优势,该海域风力发电装备需要采用浮式基础,因此研究适用于海上风力发电的浮式基础结构,对海上风力发电的产业化具有重要的意义.近年来国外开展了各种新颖浮式基础结构基础形式和工作原理的研究,针对浮式基础承受的风机运转载荷和海洋环境载荷的特点,系统分析海上风机浮式基础涉及到的关键技术问题和风险因素,对风机浮式基础设计具有参考价值.

  3. Paranoia.Ada: A diagnostic program to evaluate Ada floating-point arithmetic

    Science.gov (United States)

    Hjermstad, Chris

    1986-01-01

    Many essential software functions in the mission critical computer resource application domain depend on floating point arithmetic. Numerically intensive functions associated with the Space Station project, such as emphemeris generation or the implementation of Kalman filters, are likely to employ the floating point facilities of Ada. Paranoia.Ada appears to be a valuabe program to insure that Ada environments and their underlying hardware exhibit the precision and correctness required to satisfy mission computational requirements. As a diagnostic tool, Paranoia.Ada reveals many essential characteristics of an Ada floating point implementation. Equipped with such knowledge, programmers need not tremble before the complex task of floating point computation.

  4. Floating point only SIMD instruction set architecture including compare, select, Boolean, and alignment operations

    Science.gov (United States)

    Gschwind, Michael K.

    2011-03-01

    Mechanisms for implementing a floating point only single instruction multiple data instruction set architecture are provided. A processor is provided that comprises an issue unit, an execution unit coupled to the issue unit, and a vector register file coupled to the execution unit. The execution unit has logic that implements a floating point (FP) only single instruction multiple data (SIMD) instruction set architecture (ISA). The floating point vector registers of the vector register file store both scalar and floating point values as vectors having a plurality of vector elements. The processor may be part of a data processing system.

  5. Formulation and in-vitro evaluation of floating bilayer tablet of lisinopril maleate and metoprolol tartrate.

    Science.gov (United States)

    Ijaz, Hira; Qureshi, Junaid; Danish, Zeeshan; Zaman, Muhammad; Abdel-Daim, Mohamed; Hanif, Muhammad; Waheed, Imran; Mohammad, Imran Shair

    2015-11-01

    The purpose of this study was to introduce the technology for the development of rate-controlled oral drug delivery system to overcome various physiological problems. Several approaches are being used for the purpose of increasing the gastric retentive time, including floating drug delivery system. Gastric floating lisinopril maleate and metoprolol tartrate bilayer tablets were formulated by direct compression method using the sodium starch glycolate, crosscarmellose sodium for IR layer. Eudragit L100, pectin, acacia as sustained release polymers in different ratios for SR metoprolol tartrate layer and sodium bicarbonate, citric acid as gas generating agents for the floating extended release layer. The floating bilayer tablets of lisinopril maleate and metoprolol tartrate were designed to overcome the various problems associated with conventional oral dosage form. Floating tablets were evaluated for floating lag time, drug contents and in-vitro dissolution profile and different kinetic release models were applied. It was clear that the different ratios of polymers affected the drug release and floating time. L2 and M4 showed good drug release profile and floating behavior. The linear regression and model fitting showed that all formulation followed Higuchi model of drug release model except M4 that followed zero order kinetic. From the study it is evident that a promising controlled release by floating bilyer tablets of lisinopril maleate and metoprolol tartrate can be developed successfully.

  6. The Floating Upper Limb: Multiple Injuries Involving Ipsilateral, Proximal, Humeral, Supracondylar, and Distal Radial Limb

    Science.gov (United States)

    Manaan, Qazi; Bashir, Adil; Zahoor, Adnan; Mokhdomi, Taseem A.

    2016-01-01

    Floating arm injury represents a common yet complicated injury of the childhood severely associated with limb deformation and even morbidity, if not precisely addressed and credibly operated. Here, we report a rare floating upper limb case of a 9-year-old boy with multiple injuries of ipsilateral proximal humeral, supracondylar and distal radial limb. This is the first report to document such a combined floating elbow and floating arm injury in the same limb. In this report, we discuss the surgical procedures used and recovery of the patient monitored to ascertain the effectiveness of the method in limb reorganisation. PMID:27583121

  7. Preparation and pharmacokinetics study on gastro-floating sustained-release tablets of troxipide.

    Science.gov (United States)

    Gao, Yunyun; Gao, Yang; Yin, Fei; Wang, Mi; Wang, Zhenhong; Ye, Tiantian; Yang, Yonggang; Pan, W S; Yang, Xinggang

    2015-01-01

    The purpose of this research aimed at preparing gastro-floating sustained-release tablets of troxipide and a further study on in vitro release and in vivo bioavailability. Under the circumstances of direct powder compression, the floating tablets were successfully prepared with HPMC as main matrix material, Carbopol as assistant matrix material, octadecanol as floating agent and sodium bicarbonate as foaming agent to float by gas-forming. The floating time and accumulative release amount as evaluation indexes were utilized to perform pre-experiment screening and single-factor test, respectively, while central composite design response surface method was applied for formulation optimization, followed by in vivo pharmacokinetic study in beagles after oral administration for floating tablets and commercial tablets used as the control. The results indicated that the floating sustained-release tablets held a better capability for floating and drug release and more satisfactory pharmacokinetic parameters, such as a lower Cmax, a prolonged Tmax, but an equivalent bioavailability calculated by AUC0-24 compared to commercial tablets. So a conclusion was finally drawn that the floating sustained-release tablets possessing a good release property could be suitable for demands of design.

  8. Software implementation of floating-Point arithmetic on a reduced-Instruction-set processor

    Energy Technology Data Exchange (ETDEWEB)

    Gross, T.

    1985-11-01

    Current single chip implementations of reduced-instruction-set processors do not support hardware floating-point operations. Instead, floating-point operations have to be provided either by a coprocessor or by software. This paper discusses issues arising from a software implementation of floating-point arithmetic for the MIPS processor, an experimental VLSI architecture. Measurements indicate that an acceptable level of performance is achieved, but this approach is no substitute for a hardware accelerator if higher-precision results are required. This paper includes instruction profiles for the basic floating-point operations and evaluates the usefulness of some aspects of the instruction set.

  9. Neutrally floating objects of density 1/2 in three dimensions

    CERN Document Server

    Várkonyi, Péter L

    2012-01-01

    This paper is concerned with the Floating Body Problem of S. Ulam: the existence of objects other than the sphere, which can float in a liquid in any orientation. Despite recent results of F. Wegner pointing towards an affirmative answer, a full proof of their existence is still unavailable. For objects with cylindrical symmetry and density 1/2, the conditions of neutral floating are formulated as an initial value problem, for which a unique solution is predicted in certain cases by a suitable generalization of the Picard-Lindel\\"of theorem. Numerical integration of the initial value problem provides a rich variety of neutrally floating shapes.

  10. The Floating Upper Limb: Multiple Injuries Involving Ipsilateral, Proximal, Humeral, Supracondylar, and Distal Radial Limb.

    Science.gov (United States)

    Manaan, Qazi; Bashir, Adil; Zahoor, Adnan; Mokhdomi, Taseem A; Danish, Qazi

    2016-09-01

    Floating arm injury represents a common yet complicated injury of the childhood severely associated with limb deformation and even morbidity, if not precisely addressed and credibly operated. Here, we report a rare floating upper limb case of a 9-year-old boy with multiple injuries of ipsilateral proximal humeral, supracondylar and distal radial limb. This is the first report to document such a combined floating elbow and floating arm injury in the same limb. In this report, we discuss the surgical procedures used and recovery of the patient monitored to ascertain the effectiveness of the method in limb reorganisation.

  11. Time persistency of floating particle clusters in free-surface turbulence

    CERN Document Server

    Lovecchio, Salvatore; Soldati, Alfredo

    2013-01-01

    We study the dispersion of light particles floating on a flat shear-free surface of an open channel in which the flow is turbulent. This configuration mimics the motion of buoyant matter (e.g. phytoplankton, pollutants or nutrients) in water bodies when surface waves and ripples are smooth or absent. We perform direct numerical simulation of turbulence coupled with Lagrangian particle tracking, considering different values of the shear Reynolds number (Re{\\tau} = 171 and 509) and of the Stokes number (0.06 < St < 1 in viscous units). Results show that particle buoyancy induces clusters that evolve towards a long-term fractal distribution in a time much longer than the Lagrangian integral fluid time scale, indicating that such clusters over-live the surface turbulent structures which produced them. We quantify cluster dynamics, crucial when modeling dispersion in free-surface flow turbulence, via the time evolution of the cluster correlation dimension.

  12. A pinned or free-floating rigid plate on a thin viscous film

    KAUST Repository

    Trinh, Philippe H.

    2014-11-11

    © 2014 Cambridge University Press. A pinned or free-floating rigid plate lying on the free surface of a thin film of viscous fluid, which itself lies on top of a horizontal substrate that is moving to the right at a constant speed is considered. The focus of the present work is to describe how the competing effects of the speed of the substrate, surface tension, viscosity, and, in the case of a pinned plate, the prescribed pressure in the reservoir of fluid at its upstream end, determine the possible equilibrium positions of the plate, the free surface, and the flow within the film. The present problems are of interest both in their own right as paradigms for a range of fluid-structure interaction problems in which viscosity and surface tension both play an important role, and as a first step towards the study of elastic effects.

  13. Quantum chemical calculations using the Floating Point Systems, Inc. Model 164 attached processor

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, R.; Bair, R.A.; Eades, R.A.; Wagner, A.F.; Davis, M.J.; Harding, L.B.; Dunning, T.H. Jr.

    1983-01-01

    The Theoretical Chemistry Group at Argonne National Laboratory has had a Floating Point System, Inc., Model 164 Attached Processor (FPS-164) for several months. Actual production calculations, as well as benchmark calculations, indicate that the FPS-164 is capable of performance comparable to large mainframe computers, the groups experience with the FPS-164 includes the conversion of a complete system of electronic structure codes, including integral evaluation programs, generalized valence bond programs, integral transformation programs, and unitary group configuration interaction programs, and two classical trajectory codes. Timings of these programs at various levels of optimization along with estimates of the amount of effort required to make the necessary program modifications are discussed. 10 references, 2 figures, 2 tables.

  14. High-Precision Floating-Point Arithmetic in ScientificComputation

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, David H.

    2004-12-31

    At the present time, IEEE 64-bit floating-point arithmetic is sufficiently accurate for most scientific applications. However, for a rapidly growing body of important scientific computing applications, a higher level of numeric precision is required: some of these applications require roughly twice this level; others require four times; while still others require hundreds or more digits to obtain numerically meaningful results. Such calculations have been facilitated by new high-precision software packages that include high-level language translation modules to minimize the conversion effort. These activities have yielded a number of interesting new scientific results in fields as diverse as quantum theory, climate modeling and experimental mathematics, a few of which are described in this article. Such developments suggest that in the future, the numeric precision used for a scientific computation may be as important to the program design as are the algorithms and data structures.

  15. Floating zone growth of α-Na0.90MnO2 single crystals

    Science.gov (United States)

    Dally, Rebecca; Clément, Raphaële J.; Chisnell, Robin; Taylor, Stephanie; Butala, Megan; Doan-Nguyen, Vicky; Balasubramanian, Mahalingam; Lynn, Jeffrey W.; Grey, Clare P.; Wilson, Stephen D.

    2017-02-01

    Single crystal growth of α-NaxMnO2 (x=0.90) is reported via the floating zone technique. The conditions required for stable growth and intergrowth-free crystals are described along with the results of trials under alternate growth atmospheres. Chemical and structural characterizations of the resulting α-Na0.90MnO2 crystals are performed using ICP-AES NMR, XANES, XPS, and neutron diffraction measurements. As a layered transition metal oxide with large ionic mobility and strong correlation effects, α-NaxMnO2 is of interest to many communities, and the implications of large volume, high purity, single crystal growth are discussed.

  16. Hydrodynamics of a Free Floating Vertical Axisymmetric Oscillating Water Column Device

    Directory of Open Access Journals (Sweden)

    S. A. Mavrakos

    2012-01-01

    Full Text Available This paper aims at presenting a general formulation of the hydrodynamic problem of a floating or restrained oscillating water column device. Three types of first-order boundary value problems are investigated in order to calculate the velocity potential of the flow field around the device. The horizontal and vertical exciting wave forces, the rolling moment, the hydrodynamic parameters, the volume flows, and the drift forces are obtained in order to find the loads on the structure. The efficiency rate of the device is calculated in connection with the absorbed power and the capture length of energy absorption. Finally, the resulting wave motion inside and outside the device and the inner air pressure are examined.

  17. The effectiveness of moving masses in reducing the roll motion of floating vessels

    DEFF Research Database (Denmark)

    Montazeri, N.; Mousavizadegan, S.H.; Bakhtiarinejad, F.

    2010-01-01

    stabilizers such as rudder, fins, etc. They may be divided into two categories of passive and active stabilizers or controllers. However controlling devices may be high in cost. Moving masses are employed to reduce the motions of floating vessels or offshore structures. This type of stabilizers consists......Dynamic motions of Ships in severe conditions of sea maybe undesired and should be controlled by some devices. The rollmotion is much more significant than the other oscillations which can affect comfort, safety and efficiency of navigation at sea. This motion is controlled by some common...... with the equation of movement of the mass in both frequency-domainand time-domain by analytical and numerical approaches. The computation shows that with an optimum passive control, amoving mass with maximum 2% of the displacement of the ship is an effective device in roll minimization and enhance the vessel...

  18. Floating Zone Growth and Thermionic Emission Property of Single Crystal CeB6

    Institute of Scientific and Technical Information of China (English)

    BAO Li-Hong; ZHANG Jiu-Xing; ZHOU Shen-Lin; ZHANG Ning; XU Hong

    2011-01-01

    @@ Large-sized and high-quality cerium hexaboride(CeB6) single crystals are successfully grown yb the optical floating zone method.The structure, chemical composition and thermionic emission properties of the crystal are characterized by x-ray diffraction, x-ray fluorescence and emission measurements, respectively.Based on the observation of single crystal diffraction, the relative density of feed rods has a great effect on the quality of the grown crystal.The thermionic emission measurement results show that the emission current density of the single crystal is 47.1 A/cm2 at 1873K with an applied voltage of 1 kV,which is about two times larger than the value for polycrystalline samples.The single crystal possesses excellent emission current stability.Therefore, it is expected that CeBs single crystal is a very promising material for thermionic cathode applications.

  19. Reliability-based dynamic positioning of floating vessels with riser and mooring system

    DEFF Research Database (Denmark)

    Fang, Shaoji; Leira, Bernt J.; Blanke, Mogens

    2011-01-01

    To maintain safety of a floating vessel with associated slender components such as risers and mooring line, the vessel is normally kept within a limited region. To specify a safe position in that region, this paper suggests a new position chasing algorithm with the consideration of both riser...... angles and mooring line tensions. The riser angles were considered in an object function in [1] and the mooring line tension was considered in an object function in [2]. The contribution of this paper is to combine riser angle and mooring line tension together in one unified object function....... A combination of scaled riser angles and structural reliability index is utilized to evaluate the “reserve capacity” relative to failure events. With this object function, the riser angles and mooring line tension are considered in a unified formulation, with higher weight added to the riser angles due...

  20. AN EFFICIENT, BOX SHAPE INDEPENDENT NONBONDED FORCE AND VIRIAL ALGORITHM FOR MOLECULAR-DYNAMICS

    NARCIS (Netherlands)

    Bekker, H.; Dijkstra, E.J; Renardus, M.K.R.; Berendsen, H.J.C.

    1995-01-01

    A notation is introduced and used to transform a conventional specification of the non-bonded force and virial algorithm in the case of periodic boundary conditions into an alternative specification. The implementation of the transformed specification is simpler and typically a factor of 1.5 faster