Design charts for arbitrarily pivoted, liquid-lubricated flat-sector-pad thrust bearing

Science.gov (United States)

Etsion, I.

1977-01-01

A flat, sector-shaped geometry for a liquid-lubricated thrust bearing is analyzed considering both the pitch and roll of the pad. Results are presented in design charts that enable a direct approach to the design of point- and line-pivoted, tilting pad bearings. A comparison is made with the Mitchell bearing approximation and it is found that this approximation always overestimates load capacity.

Experimental test of static and dynamic characteristics of tilting-pad thrust bearings

OpenAIRE

Annan Guo; Xiaojing Wang; Jian Jin; Diann Y Hua; Zikai Hua

2015-01-01

The axial vibration in turbine machine has attracted more and more interest. Tilting-pad thrust bearings are widely used in turbine machines to support the axial load. The dynamic properties generated by oil film of the thrust pad have important effects on the axial vibration of the rotor-bearing system. It is necessary to develop the method to test the dynamic characteristics of thrust bearings. A new rig has been developed. The facility allows a complete set of bearing operating parameters ...

Improvement of Thrust Bearing Calculation Considering the Convectional Heating within the Space between the Pads

OpenAIRE

Monika Chmielowiec-Jablczyk; Andreas Schubert; Christian Kraft; Hubert Schwarze; Michal Wodtke; Michal Wasilczuk

2018-01-01

A modern thrust bearing tool is used to estimate the behavior of tilting pad thrust bearings not only in the oil film between pad and rotating collar, but also in the space between the pads. The oil flow in the space significantly influences the oil film inlet temperature and the heating of pad and collar. For that reason, it is necessary to define an oil mixing model for the space between the pads. In the bearing tool, the solutions of the Reynolds equation including a cavitation model, the ...

Improvement of Thrust Bearing Calculation Considering the Convectional Heating within the Space between the Pads

Directory of Open Access Journals (Sweden)

Monika Chmielowiec-Jablczyk

2018-02-01

Full Text Available A modern thrust bearing tool is used to estimate the behavior of tilting pad thrust bearings not only in the oil film between pad and rotating collar, but also in the space between the pads. The oil flow in the space significantly influences the oil film inlet temperature and the heating of pad and collar. For that reason, it is necessary to define an oil mixing model for the space between the pads. In the bearing tool, the solutions of the Reynolds equation including a cavitation model, the energy equation and the heat transfer equation are done iteratively with the finite volume method by considering a constant flow rate. Both effects—laminar/turbulent flow and centrifugal force—are considered. The calculation results are compared with measurements done for a flooded thrust bearing with nominal eight tilting pads with an outer diameter of 180 mm. The heat convection coefficients for the pad surfaces mainly influence the pad temperature field and are adjusted to the measurement results. In the following paper, the calculation results for variable space distances, influence of different parameters on the bearing behavior and operating condition at high load are presented.

On the simplifications for the thermal modeling of tilting-pad journal bearings under thermoelastohydrodynamic regime

DEFF Research Database (Denmark)

Cerda Varela, Alejandro Javier; Fillon, Michel; Santos, Ilmar

2012-01-01

formulation for inclusion of the heat transfer effects between oil film and pad surface. Such simplified approach becomes necessary when modeling the behavior of tilting-pad journal bearings operating on controllable lubrication regime. Three different simplified heat transfer models are tested, by comparing...... are strongly dependent on the Reynolds number for the oil flow in the bearing. For bearings operating in laminar regime, the decoupling of the oil film energy equation solving procedure, with no heat transfer terms included, with the pad heat conduction problem, where the oil film temperature is applied......The relevance of calculating accurately the oil film temperature build up when modeling tilting-pad journal bearings is well established within the literature on the subject. This work studies the feasibility of using a thermal model for the tilting-pad journal bearing which includes a simplified...

Establishment of Approximate Analytical Model of Oil Film Force for Finite Length Tilting Pad Journal Bearings

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Yongliang Wang

2015-01-01

Full Text Available Tilting pad bearings offer unique dynamic stability enabling successful deployment of high-speed rotating machinery. The model of dynamic stiffness, damping, and added mass coefficients is often used for rotordynamic analyses, and this method does not suffice to describe the dynamic behaviour due to the nonlinear effects of oil film force under larger shaft vibration or vertical rotor conditions. The objective of this paper is to present a nonlinear oil force model for finite length tilting pad journal bearings. An approximate analytic oil film force model was established by analysing the dynamic characteristic of oil film of a single pad journal bearing using variable separation method under the dynamic π oil film boundary condition. And an oil film force model of a four-tilting-pad journal bearing was established by using the pad assembly technique and considering pad tilting angle. The validity of the model established was proved by analyzing the distribution of oil film pressure and the locus of journal centre for tilting pad journal bearings and by comparing the model established in this paper with the model established using finite difference method.

Study on the prevention of spragging in a tilting pad journal bearing using the variation of preload

International Nuclear Information System (INIS)

Yang, Seong Heon; Park, Chul Hyun; Ha, Hyun Cheon; Kim, Chae Sil

2001-01-01

Tilting pad journal bearings have been widely used in a high speed rotating machinery, such as steam turbines and gas turbines, owing to their inherent stability characteristics. However, some peculiar fatigue failure in the babbitt metal due to spragging has been continuously occurred at the leading edge of the upper pads. The spragging is defined as the pad vibration initiated on the upper unloaded pads in tilting pad journal bearing. This paper describes both several kinds of bearing failure related with spragging and the theoretical investigation on the prevention of the spragging phenomenon using the variation of preload. Results show that positive preload(m>0.5) assures all pads remain statically loaded under all operating conditions. For the change of design parameter to prevent spragging, thermo-hydrodynamic lubrication and rotor dynamic analysis were performed to verify temperature limitation on bearing and vibration problems on rotor bearing system

Design Optimization of Tilting-Pad Journal Bearing Using a Genetic Algorithm

Directory of Open Access Journals (Sweden)

Hamit Saruhan

2004-01-01

Full Text Available This article focuses on the use of genetic algorithms in developing an efficient optimum design method for tilting pad bearings. The approach optimizes based on minimum film thickness, power loss, maximum film temperature, and a global objective. Results for a five tilting-pad preloaded bearing are presented to provide a comparison with more traditional optimum design methods such as the gradient-based global criterion method, and also to provide insight into the potential of genetic algorithms in the design of rotor bearings. Genetic algorithms are efficient search techniques based on the idea of natural selection and genetics. These robust methods have gained recognition as general problem solving techniques in many applications.

Thermal–Hydrodynamic Behaviour of Coated Pivoted Pad Thrust Bearings: Comparison between Babbitt, PTFE and DLC

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Konstantinos Katsaros

2018-05-01

Full Text Available The hydrodynamic lubrication and thermal analysis of tilting pad thrust bearings has been a major subject for many studies in the field of tribology. There is only a limited number of studies regarding thrust bearings with coated surfaces. The purpose of this study is to build a parametric, iterative algorithm in order to perform a complete thermal and hydrodynamic lubrication analysis for pivoted pad thrust bearings with coatings. The analytical model is mainly based on the energy, continuity and Navier–Stokes equations, which are solved numerically with the Semi-Implicit Method for Pressure Linked Equations Consistent (SIMPLEC method. The analysis focuses on a single pivoted pad of the thrust bearing. The thermal properties of the coating material are taken into account and the resulting thermal and flow fields are solved. The basic hydrodynamic and tribological characteristics are calculated for an uncoated, a Babbitt coated, a PTFE coated and a diamond like carbon (DLC coated pivoted pad thrust bearing. The pressure and the film thickness distribution, as well as the load capacity and the frictional forces, are determined for several pad positions and velocities of the rotor. A mineral oil lubricant is used to estimate the shear thinning or thickening effects on the pad tribological performance. The results indicate that pads coated with PTFE and DLC show lower friction forces compared to the common steel and Babbitt applications. At the same time, the DLC coating seems to affect the bearing’s flow and thermal fields less than the PTFE, making it more suitable for thrust bearings applications.

On the Possibilities of Decreasing Power Loss in Large Tilting Pad Thrust Bearings

OpenAIRE

Wasilczuk, Michal; Rotta, Grzegorz

2013-01-01

Different systems of direct oil supply have been developed in order to facilitate efficient introduction of fresh lubricant to the oil gap and reduction of churning power loss in tilting pad thrust bearings. Up to now there is no documented application of the supply groove in large thrust bearings used in water power plants. The results of modeling lubricant flow in the lubricating groove of a thrust bearing pad will be presented in the paper. CFD software was used to carry out fluid film cal...

Investigation on laser welding characteristics for appendage of bearing pads of nuclear fuel element

International Nuclear Information System (INIS)

Kim, S. S.; Kim, W. K.; Park, C. H.; Ko, J. H.; Lee, J. W.; Yang, M. S.

2001-01-01

In CANDU nuclear fuel manufacturing the brazing technology has been adopted conventionally to attach the bearing pads of nuclear fuel elements. However, in order to meet good performance of nuclear fuel and improved working efficiency, we started developing the laser welding technology for attachments of the bearing pads. Since the YAG laser can be suitable for small parts and transmit the beam through the optical fiber, the process is corresponding to mass-production with working shops. Making the most of this feature, we have developed the laser welding for appendage of the bearing pads of nuclear fuel elements, and has studied on the laser welding characterisitcs of appendages for nuclear fuel element

Experimental and Numerical Simulation of Unbalance Response in Vertical Test Rig with Tilting-Pad Bearings

Directory of Open Access Journals (Sweden)

Mattias Nässelqvist

2014-01-01

Full Text Available In vertically oriented machines with journal bearing, there are no predefined static radial loads, such as dead weight for horizontal rotor. Most of the commercial software is designed to calculate rotordynamic and bearing properties based on machines with a horizontally oriented rotor; that is, the bearing properties are calculated at a static eccentricity. For tilting-pad bearings, there are no existing analytical expressions for bearing parameters and the bearing parameters are dependent on eccentricity and load angle. The objective of this paper is to present a simplified method to perform numerical simulations on vertical rotors including bearing parameters. Instead of recalculating the bearing parameters in each time step polynomials are used to represent the bearing parameters for present eccentricities and load angles. Numerical results are compared with results from tests performed in a test rig. The test rig consists of two guide bearings and a midspan rotor. The guide bearings are 4-pad tilting-pad bearings. Shaft displacement and strains in the bearing bracket are measured to determine the test rig’s properties. The comparison between measurements and simulated results shows small deviations in absolute displacement and load levels, which can be expected due to difficulties in calculating exact bearing parameters.

Micro-focus x-ray inspection of the bearing pad welded by laser for CANDU fuel element

International Nuclear Information System (INIS)

Kim, W. K.; Kim, S. S.; Lee, J. W.; Yang, M. S.

2001-01-01

To attach the bearing pads on the surface of CANDU fuel element, laser welding technique has been reviewed to replace brazing technology which is complicate process and makes use of the toxic beryllium. In this study, to evaluate the soundness of the weld of the bearing pad of CANDU fuel element, a precise X-ray inspection system was developed using a micro-focus X-ray generator with an image intensifier and a real time camera system. The weld of the bearing pad welded by Nd:YAG laser has been inspected by the developed inspection system. Image processing technique has been applied to reduce random noise and to enhance the contrast of the X-ray image. A few defects on the weld of the bearing pads have been detected by the X-ray inspection process

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings: Part I – Theory

DEFF Research Database (Denmark)

Heinrichson, Niels; Santos, Ilmar

2006-01-01

This is Part I of a two-part series of papers describing the effects of high pressure injection pockets on the operating conditions of tilting-pad thrust bearings. A numerical model based on the Reynolds equation is developed extending the three dimensional thermo-elasto-hydrodynamic (TEHD......) analysis of tilting-pad thrust bearings to include the effects of high pressure injection and recesses in the bearing pad. The model is applied to the analysis of an existing bearing of large dimensions and the influence of the pocket is analyzed. It is shown that a shallow pocket positively influences...... the performance of the bearing as it has characteristics similar to those of a parallel step bearing....

The Impact of Convective Fluid Inertia Forces on Operation of Tilting-Pad Journal Bearings

Directory of Open Access Journals (Sweden)

Thomas Hagemann

2017-01-01

Full Text Available This paper presents a combination of experimental data, CFD analyses, and bearing code predictions on emergence of convective inertia fluid forces within the lube oil flow of tilting-pad journal bearings. Concordantly, experimental data and CFD analyses show a significant rise of local pressure at the transition between inlet and leading edge of tilting-pad, especially for high-speed applications with surface speeds up to 100 m/s. This effect can be related to convective inertia forces within fluid flow as cross-sections and flow character rapidly change at the pad entrance. An energy-based approach is implemented in the bearing code in order to provide enhanced boundary conditions for Reynolds equation considering this effect. As a result, predictions of bearing code achieved significant improved correlation with measured pressure distributions and CFD-data. Further, beside the local influence, a nonnegligible impact on characteristic parameters of bearing operation such as maximum temperature and stiffness and damping coefficients is observed. Finally, the results are critically analyzed and requirements to gain more distinct and reliable data are specified.

An approach to evaluate capacitance, capacitive reactance and resistance of pivoted pads of a thrust bearing

Science.gov (United States)

Prashad, Har

1992-07-01

A theoretical approach is developed for determining the capacitance and active resistance between the interacting surfaces of pivoted pads and thrust collar, under different conditions of operation. It is shown that resistance and capacitive reactance of a thrust bearing decrease with the number of pads times the values of these parameters for an individual pad, and that capacitance increases with the number of pads times the capacitance of an individual pad. The analysis presented has a potential to diagnose the behavior of pivoted pad thrust bearings with the angle of tilt and the ratio of film thickness at the leading to trailing edge, by determining the variation of capacitance, resistance, and capacitive reactance.

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings - Part I: Theory

DEFF Research Database (Denmark)

Heinrichson, Niels; Santos, Ilmar; Fuerst, Axel

2007-01-01

This is Part I of a two-part series of papers describing the effects of high-pressure injection pockets on the operating conditions of tilting-pad thrust bearings. In Part I a numerical model based on the Reynolds equation is developed extending the threedimensional thermoelastohydrodynamic (TEHD......) analysis of tilting-pad thrust bearings to include the effects of high-pressure injection and recesses in the bearing pads. The model is applied to the analysis of an existing bearing of large dimensions and the influence of the pocket is analyzed. In the analysis, the high-pressure oil injection used...... for hydrostatic jacking is turned off (i.e., only the effect of the pocket is studied). It is shown that a shallow pocket positively influences the performance of the bearing because it has characteristics similar to those of a Rayleigh-step bearing. In Part II of the paper (Heinrichson, N., Fuerst, A...

Thermal–Hydrodynamic Behaviour of Coated Pivoted Pad Thrust Bearings: Comparison between Babbitt, PTFE and DLC

OpenAIRE

Konstantinos Katsaros; Dimitrios A. Bompos; Pantelis G. Nikolakopoulos; Stephanos Theodossiades

2018-01-01

The hydrodynamic lubrication and thermal analysis of tilting pad thrust bearings has been a major subject for many studies in the field of tribology. There is only a limited number of studies regarding thrust bearings with coated surfaces. The purpose of this study is to build a parametric, iterative algorithm in order to perform a complete thermal and hydrodynamic lubrication analysis for pivoted pad thrust bearings with coatings. The analytical model is mainly based on the energy, continuit...

Structural response testing of thermal barrier load-bearing ceramic pads

International Nuclear Information System (INIS)

Black, W.E.; Luci, R.K.; Pickering, J.L.; Oland, G.B.

1983-01-01

A load bearing insulating structure for use in a HTGR was investigated. The structure was composed of dense ceramic materials in the form of circular pads arranged in a stack. Specifically, the test program was structured to investigate the isolation effectiveness of interface materials placed between the ceramic pads to reduce the effectiveness of mechanically induced loads. The tests were conducted at room temperature using tapered loading platens on single ceramic pads. Seventeen alumina specimens, representing two types of material and two thicknesses, were tested. Three interface material thicknesses were introduced using silica cloth and graphite foil. Pre and post test nondestructive examinations were conducted in an effort to identify potential damage-inducing anomalies in the ceramic pads. A total of 62 tests was conducted with all specimens eventually loaded to failure. (orig./HP)

Characterization of High-Power Turbomachinery Tilting Pad Journal Bearings: First Results Obtained on a Novel Test Bench

Directory of Open Access Journals (Sweden)

Enrico Ciulli

2018-01-01

Full Text Available Tilting pad journal bearings are usually employed in turbomachines for their stable behavior at high rotational speeds. Devoted test rigs have been realized to validate the predictions of theoretical models. However, the design of new high-performance and large-size bearings needs to be supported by experimental investigations on high-performance large test rigs. The main characteristics of a recently built facility for testing large tilting pad journal bearings with diameters from 150 to 300 mm are described in this work. The test rig is versatile and can be used to test bearings of different size, configurations and to investigate the influence of many parameters, even the effect of misalignment. Sample results of the static characterization of a four-pad high-performance tilting pad journal bearing are reported evidencing some transient effects. A few sample dynamic results are also reported. The presented experimental results demonstrated the capabilities of the rig for investigating the static and the dynamic characteristics of the bearings accurately measuring slow and fast variables.

Influence of bearing pre-load coefficient on shaft vibration and pad temperature in a hydroturbine generator unit. A case study

Energy Technology Data Exchange (ETDEWEB)

Feng Fuzhou; Chu Fulei; Guo Dan; Lu Wenxiu [Tsinghua Univ., Beijing, BJ (China). Dept. of Precision Instruments

2001-07-01

From data collected by an online condition monitoring and fault diagnosis system, a higher pad temperature at the upper guide bearing in a pumped storage power generator unit installed in Guangdong province(GPSPS), China, was found. And also a relatively intensive shaft vibration occurred at the lower guide bearing. By calculating the Reynolds equation and viscosity-temperature equation of the lubricant, a curve between the pre-load coefficient and the increment of pad temperature is obtained, which shows that the larger, the pre-load coefficient, the bigger, the increment of pad temperature. For a practical unit in GPSPS, by employing Transfer matrix method and Wilson-{theta} method to analyze shaft vibration at different pre-load coefficients of the whole bearing or ''pad pair'' bearings, the results show that the larger the pre-load coefficient is, the smaller the vibration amplitude is, the shorter the time for vibration to become steady is. And an uneven pre-load coefficient of the ''pad pair'' bearings will cause shaft orbit from a circle to an ellipse whose long axes is at the direction of the ''pad pair'' with the lowest pre-load coefficient. Finally, reasons of higher pad temperature of the upper guide bearing and larger shaft vibration at the lower guide bearing are due to the inconsistent relation of bearing assembling clearance or pre-load coefficient of the upper and lower guide bearing, and also due to the too small, uneven pre-load coefficient of ''pad pair'' bearings. After a scheme for adjusting the bearing clearance is given, data measured show that the analysis and simulation methods are correct and the adjustment scheme to the assembling clearance of the upper and lower guide bearings is feasible and can be used to guide the field maintenance conveniently. (orig.)

Analysis of a Thrust Bearing with Flexible Pads and Flexible Supports

DEFF Research Database (Denmark)

Klit, Peder; Thomsen, Kim

2007-01-01

A theoretical analysis of a hydrodynamic thrust bearing is presented. The bearing investigated is used in an ndustrial product. The lubricant is water, but the results are valid also for other lubricants.At first the results from a 1-dimensional model for the fluid film forces and the associated...... deformation of the bearing geometry is presented. This model enlightens the influence of pad flexibility and support location and flexibility. Subsequently results from a 2-dimensional model of the bearing is presented. The model is used to carry out an optimization of the bearing design, and the obtained...

Measurement of fluid film thickness on the valve plate in oil hydraulic axial piston pumps (I): bearing pad effects

International Nuclear Information System (INIS)

Kim, Jong Ki; Jung, Jae Youn

2003-01-01

The tribological mechanism between the valve plate and the cylinder block in oil hydraulic axial piston pumps plays an important role on high power density. In this study, the fluid film thickness between the valve plate and the cylinder block was measured with discharge pressure and rotational speed by use of a gap sensor, and a slip ring system in the operating period. To investigate the effect of the valve plate shapes, we designed two valve plates with different shapes: the first valve plate was without a bearing pad, while the second valve plate had a bearing pad. It was found that both valve plates behaved differently with respect to the fluid film thickness characteristics. The leakage flow rates and the shaft torque were also experimented in order to clarify the performance difference between the valve plate without a bearing pad and the valve plate with a bearing pad. From the results of this study, we found out that in the oil hydraulic axial piston pumps, the valve plate with a bearing pad showed better film thickness contours than the valve plate without a bearing pad

Component level study of an actively lubricated LEG Tilting Pad Bearing: Theory and experiment

DEFF Research Database (Denmark)

Cerda Varela, Alejandro Javier; Santos, Ilmar Ferreira

2018-01-01

portrays the first experimental study for the“proof of concept” of this configuration, as well as a comparison with theoretical results. A simplified setup, featuring a rigid rotor supported by a single pad arrangement is the subject of study. The obtained results prove the viability of the proposed active...... bearing design, validate the available simulation tool and exemplify on a conceptual level the operational benefits from introducing this technology into standard LEG Tilting Pad Bearings....

Structural response testing of thermal barrier load bearing ceramic pads

International Nuclear Information System (INIS)

Pickering, J.L.; Black, W.E.; Luci, R.K.; Oland, C.B.

1983-01-01

A load-bearing insulating structure for use in a high-temperature gas-cooled reactor (HTGR) was investigated. The structure was composed of dense ceramic materials in the form of circular pads arranged in a stack. Specifically, the test program was structured to investigate the isolation effectiveness of interface materials placed between the ceramic pads to reduce the effectiveness of mechanically induced loads. The tests were conducted at room temperature using tapered loading platens on single ceramic pads. Seventeen alumina specimens, representing two types of material and two thicknesses, were tested. Three interface material thicknesses were introduced using silica cloth and graphite foil. Pre- and post-test nondestructive examinations were conducted in an effort to identify potential damage-inducing anomalies in the ceramic pads. A total of 62 tests was conducted with all specimens eventually loaded to failure

On the Controllability and Observability of Actively Lubricated Journal Bearings with Pads Featuring Different Nozzle-Pivot Configurations

DEFF Research Database (Denmark)

Salazar, Jorge Andrés González; Santos, Ilmar

2017-01-01

tilt angle, (iii) the vertical pad movement-due to the pivot flexibility, and (iv) the controllable force as the hydraulic DOF. The test rig consists of a rigid rotor supported by a single rocker-pivoted rigid pad. A thorough parametric study is carried out by investigating the effects of: (a) nozzle-pivot...... offset, (b) pivot flexibility, and (c) bearing loading on these control basics in order to determine the pad with the best control characteristics. Different nozzle-pivot offsets can be set by varying the positioning of either the injection nozzle or the pivot line. The influence of the pivot compliance...... on the bearing dynamics is assessed by benchmarking the results obtained with the flexible pivot against the rigid pivot. Three different bearing loads are studied. According to the results, the proposed configurations, especially the offset-pivot pad with slight offsets, improve the bearing control...

Steady state characteristics of a tilting pad journal bearing with controllable lubrication: Comparison between theoretical and experimental results

DEFF Research Database (Denmark)

Cerda Varela, Alejandro Javier; Nielsen, Bo Bjerregaard; Santos, Ilmar

2013-01-01

direction. The modification of the injection pressure enables to modify the bearing static and dynamic properties according to the operational needs. The results presented are obtained using a theoretical model, which considers all the effects that determine the bearing behavior (controllable......This paper is aimed at presenting results regarding the static and thermal behavior of a tilting-pad journal bearing operating under controllable regime. The bearing is rendered controllable by injecting high pressure oil into the clearance using holes drilled across the bearing pads in the radial...... elastothermohydrodynamic lubrication regime), as well as using a test rig designed and built to this effect. The comparison between experimental and theoretical results provides solid ground to determine the accuracy of the available model for the the prediction of the steady-state behavior of the tilting-pad bearing...

Performance of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped flexibly mounted spiral-groove thrust bearing

Science.gov (United States)

Ream, L. W.

1974-01-01

A test program was conducted to determine the performance characteristics of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped spiral-groove thrust bearing designed for the Brayton cycle rotating unit (BRU). Hydrostatic, hybrid (simultaneously hydrostatic and hydrodynamic), and hydrodynamic tests were conducted in argon gas at ambient pressure and temperature ranges representative of operation to the 10.5 kWe BRU power-generating level. Performance of the gas lubricated bearings is presented including hydrostatic gas flow rates, bearing clearances, bearing temperatures, and transient performance.

Performance Improvement of tilting-pad journal bearings by means of controllable lubrication

DEFF Research Database (Denmark)

Cerda, Alejandro; Santos, Ilmar

2012-01-01

Tilting-Pad Journal Bearings (TPJB) are commonly used on high-performance turbomachinery due to their excellent stability properties at high speed when compared to other designs for oil film bearings. Hence, efforts have been made to improve the accuracy for the available models for these mechani...... is used to show the benefits of applying a controllable lubrication regime, by means of the modification of the thermal and dynamic behaviour of the bearing....

Fault diagnosis for tilting-pad journal bearing based on SVD and LMD

Directory of Open Access Journals (Sweden)

Zhang Xiaotao

2016-01-01

Full Text Available Aiming at fault diagnosis for tilting-pad journal bearing with fluid support developed recently, a new method based on singular value decomposition (SVD and local mean decomposition (LMD is proposed. First, the phase space reconstruction of Hankel matrix and SVD method are used as pre-filter process unit to reduce the random noises in the original signal. Then the purified signal is decomposed by LMD into a series of production functions (PFs. Based on PFs, time frequency map and marginal spectrum can be obtained for fault diagnosis. Finally, this method is applied to numerical simulation and practical experiment data. The results show that the proposed method can effectively detect fault features of tilting-pad journal bearing.

Discontinuity effects in dynamically loaded tilting pad journal bearings

DEFF Research Database (Denmark)

Thomsen, Kim; Klit, Peder; Vølund, Anders

2011-01-01

This paper describes two discontinuity effects that can occur when modelling radial tilting pad bearings subjected to high dynamic loads. The first effect to be treated is a pressure build-up discontinuity effect. The second effect is a contact-related discontinuity that disappears when a contact...... force is included in the theoretical model. Methods for avoiding the pressure build-up discontinuity effect are proposed....

Feedback-controlled lubrication for reducing the lateral vibration of flexible rotors supported by tilting-pad journal bearings

DEFF Research Database (Denmark)

Salazar, Jorge Andrés González; Santos, Ilmar

2015-01-01

function is optimized in the stabilizing gain domain and then chosen from a subdomain imposed by servovalve restrictions. This work demonstrates enhancements of the dynamic response of flexible rotor-bearing systems supported by an active tilting-pad journal bearing by means of the feedback......The feedback-controlled lubrication regime, based on a model-free designed proportional–derivative controller, is experimentally investigated in a flexible rotor mounted on an actively-lubricated tilting-pad journal bearing. With such a lubrication regime, both the resulting pressure distribution...

Fuel-element vibration and bearing pad to pressure tube fretting

International Nuclear Information System (INIS)

Fisher, N.J.; Taylor, C.E.; Pettigrew, M.J.

1990-08-01

Fuel channel operation under boiling condition results in increased flow velocities, which may lead to unacceptable fuel-element vibration and bearing pad to pressure tube fretting. The existing endurance test database does not fully cover the range of future channel operating conditions. In particular, after refuelling, some channels for future designs may operate with two-phase flow conditions outside the range of endurance test conditions. Full-scale endurance testing at realistic steam-water conditions involves substantial energy costs. Therefore, fundamental laboratory investigations were conducted to define and endurance test matrix which adequately envelops the future range of operating conditions while minimizing both the number of tests and the energy requirement of individual tests. The main focus of the laboratory investigations was to establish the relationships between: fuel channel flow conditions and fuel-element vibration; and fuel-element vibration and bearing pad to pressure tube fretting. The vibration response of a single fuel element was measured over a wide range of operating conditions covering realistic fuel channel conditions and simulated endurance testing conditions. For higher void fractions, the vibration amplitudes measured in air/water were much higher than in steam/water, while for low void fractions, the amplitudes were similar. The measured amplitudes in steam/water varied very little over the range of temperature and pressure investigated. The effects of temperature, pressure tube oxide thickness, vibration amplitude and bearing pad manufacturer on pressure tube fretting were investigated. The fretting rate is extremely temperature dependent. For vibration amplitudes about three or four times greater than expected in-reactor conditions, peak fretting rates were observed in the 225 to 286 degrees C temperature range. Fretting rates were seven times less at the higher temperatures of 300 and 315 degrees C, and the lower temperatures

PROVIDING SERVICEABILITY OF STRUCTURAL BEARING TYPES FOR ROADWAY BRIDGES

Directory of Open Access Journals (Sweden)

R. I. Polyuga

2010-03-01

Full Text Available In the article the description of structural bearing types for roadway bridges and their classification is given. Special attention is paid to effective bearings with elastomeric materials – rubber, pot, spherical ones. Characteristic defects of structural bearings and demands of serviceability are noticed.

Optimal design of Tilting-Pad Thrust Bearings with High Pressure Injection Pockets

DEFF Research Database (Denmark)

Heinrichson, Niels; Santos, Ilmar

2006-01-01

A thermo-elasto-hydrodynamic(TEHD) model based on the Reynolds equation has been used to study the effect of oil injection pockets on the performance of tilting pad thrust bearings. The optimal position of the pivot both with respect to load carrying capacity and minimal power consumption is seen...

Shaking Table Tests of Curved Bridge considering Bearing Friction Sliding Isolation

Directory of Open Access Journals (Sweden)

Lei Yan

2016-01-01

Full Text Available Specific to severe damage to curved bridges in earthquakes caused by the excessive force of the fixed bearings and piers, a new seismic design method on curved bridges considering bearing friction sliding isolation is proposed in this paper. Seismic model bridge and isolation model bridge with similarity ratio of 1/20 were made and the shaking table comparison test was conducted. The experimental results show that the isolation model curved bridge suffered less seismic damage than the seismic model curved bridge. The fundamental frequencies of the seismic model bridge and isolation model bridge decreased and the damping ratio increased with the increase of seismic intensity. Compared with seismic curved bridge, the maximum reduction rates of peak acceleration along the radial and tangential directions on the top of pier of the isolation model curved bridge were 47.3% and 55.5%, respectively, and the maximum reduction rate of the peak strain on the bottom of pier of the isolation model curved bridge was 43.4%. For the isolation model curved bridge, the maximum reduction rate of peak acceleration on the top of pier was 24.6% compared with that on the bottom of pier. The study results can provide experimental basis for the seismic design of curved bridges.

Tilting-Pad Journal Bearings with Active Lubrication Applied as Calibrated Shakers: Theory and Experiment

DEFF Research Database (Denmark)

Cerda Varela, Alejandro Javier; Santos, Ilmar

2014-01-01

In recent years, a continuous research effort has transformed the conventional tilting-pad journal bearing into a mechatronic machine element. The addition of electromechanical elements provides the possibility of generating controllable forces over the rotor as a function of a suitable control...... directly into the bearing clearance. The injected flow is controlled by means of a servovalve. The theoretical model includes the dynamics of servovalves and pipelines using a lumped parameter approach, whereas the coupling between the hydraulic system and the bearing oil film is modeled using a modified...

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings - Part II: Comparison Between Theory and Experiment

DEFF Research Database (Denmark)

Heinrichson, Niels; Fuerst, Axel; Santos, Ilmar

2007-01-01

This is Part II of a two-part series of papers describing the effects of high-pressure injection pockets on the operating conditions of tilting-pad thrust bearings. The paper has two main objectives. One is an experimental investigation of the influence of an oil injection pocket on the pressure...... and without oil injection) on the pressure distribution and oil film thickness. Measurements of the distribution of pressure and oil film thickness are presented for tilting-pad thrust bearing pads of approx. 100 cm^2 surface area. Two pads are measured in a laboratory test rig at loads of approx. 1.5 MPa...... and approx. 4.0 MPa and velocities of up to 33 m/s. One pad has a plain surface. The other pad has a conical injection pocket at the pivot point and a leading-edge taper. The measurements are compared to theoretical values obtained using a three-dimensional thermoelastohydrodynamic (TEHD) numerical model...

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings: Part II – Comparison Between Theory and Experiment

DEFF Research Database (Denmark)

Heinrichson, Niels; Santos, Ilmar

2006-01-01

This is Part II of a two-part series of papers describing the effects of high pressure injection pockets on the operating conditions of tilting-pad thrust bearings. Measurements of the distribution of pressure and oil film thickness are presented for tilting-pad thrust bearing pads of approximately...... 100 cm2 surface area. Two pads are measured in a laboratory test-rig at loads of approximately 0.5, 1.5 and 4.0 MPa and velocities of up to 33 m/s. One pad has a plain surface. The other pad has a conical injection pocket at the pivot point and a leading edge taper. The measurements are compared...... to theoretical values obtained using a three dimensional thermo-elasto-hydrodynamic (TEHD) numerical model. At low and intermediate loads the theoretical pressure distribution corresponds well to the measured values for both pads although the influence of the pocket is slightly underestimated. At high loads...

Pilot Study for Investigating the Cyclic Response of the Recentering Bridge Bearing System Combined with the Friction Damper

Directory of Open Access Journals (Sweden)

Jong Wan Hu

2016-01-01

Full Text Available The bridge bearing is one of the component members which provide resting supports between piers and decks. The bridge bearing is intended to control longitudinal movement caused by traffic flow and thermal expansion, thereby reducing stress concentration. In high seismicity area, the bridge bearing has been utilized as the base isolation system to mitigate acceleration transferred from the ground. Although the existing bridge bearing installed between superstructure and substructure provides extra flexibility to the base of the entire structure, considerable permanent deformation occurs due to lack of recentering capacity after earthquake. It is required to spend extra cost for repairing impaired parts. The bridge bearings integrated with superelastic shape memory alloy (SMA devices used for upgrading the recentering effect into the friction damper are proposed in this study. The refined finite element (FE analyses are introduced to reproduce the response of such new structures under cyclic loading condition. The bridge bearing systems that maintain uniform recentering capability are designed with various friction coefficients so as to examine energy dissipation and residual deformation through FE analyses. After observing FE analysis results, optimal design for the recentering bridge bearing system will be proposed to take advantage of energy dissipation and self-centering capacity.

Calculation methods for steadily loaded, off-set pivot, tilting pad thrust bearings. (Guide to use of computer program A9235.)

Science.gov (United States)

1992-12-01

ESDU 92035 provides details of a FORTRAN program that implements the calculation method of ESDU 83004. It allows performance analysis of an existing design, or the design of a bearing dimensions, subject to any space constraint, are recommended. The predicted performance includes the lubricant film thickness under load, its temperature and flow rate, the power loss, and the bearing temperature. Recommendations are also made on surface finish. Warning messages are output in the following cases, for each of which possible remedial actions are suggested: drain or pad temperature too high, churning losses too great, film thickness too small, pad number too high, ratio or inner to outer pad radius too large, flow rate too great, lubricant or pad temperature outside usable range. A lubricant database is provided that may be extended or edited. The program applies to Newtonian lubricants in laminar flow. Worked examples illustrate the use of the program.

Active tilting-pad journal bearings supporting flexible rotors: Part II–The model-based feedback-controlled lubrication

DEFF Research Database (Denmark)

Salazar, Jorge Andrés González; Santos, Ilmar

2017-01-01

This is part II of a twofold paper series dealing with the design and implementation of model-based controllers meant for assisting the hybrid and developing the feedback-controlled lubrication regimes in active tilting pad journal bearings (active TPJBs). In both papers theoretical and experimen...... derived in part I. Results show further suppression of resonant vibrations when using the feedback-controlled or active lubrication, overweighting the reduction already achieved with hybrid lubrication, thus improving the whole machine dynamic performance.......This is part II of a twofold paper series dealing with the design and implementation of model-based controllers meant for assisting the hybrid and developing the feedback-controlled lubrication regimes in active tilting pad journal bearings (active TPJBs). In both papers theoretical...... and experimental analyses are presented with focus on the reduction of rotor lateral vibration. This part is devoted to synthesising model-based LQG optimal controllers (LQR regulator + Kalman Filter) for the feedback-controlled lubrication and is based upon the mathematical model of the rotor-bearing system...

Rotordynamic Evaluation of Full Scale Rotor on Tilting Pad Bearings with 0.1 and 0.3 Preload

Directory of Open Access Journals (Sweden)

Weimin Wang

2014-01-01

Full Text Available A system identification method for rotating machinery stability evaluation is investigated based on sine sweep excitation testing with electromagnetic actuator. The traditional MIMO FRF is transformed into dFRF from real number field to complex field with a transformation matrix, eliminating the influence of forward and backward modal overlap and providing higher accuracy to identify rotor’s first forward modal parameters using the rational polynomial method. The modal parameters are acquired for stability estimation. Furthermore, two sets of bearing with preloads of 0.1 and 0.3 under both load-on-pad (LOP and load-between-pad (LBP conditions are investigated. The effects of oil inlet pressure (1.0 bar–1.75 bar and temperature (43°C–51°C on the stability of rotor are investigated in detail. Results indicate that the stability of rotor will be improved by increasing the oil inlet temperature and pressure. It is found that the rotor is more stable on bearing with 0.1 preload than that of 0.3 preload. Load-on-pad provides more damping to rotor than load-between-pad. The method and outcomes of this paper can provide both theory basis and technology foundation for improving the rotor stability of centrifugal compressors.

Stability Analysis of an Industrial Gas Compressor Supported by Tilting-Pad Bearings Under Different Lubrication Regimes

DEFF Research Database (Denmark)

Cerda, Alejandro; Santos, Ilmar

2012-01-01

This work is aimed at a theoretical study of the dynamic behavior of a rotor-tilting pad journal bearing (TPJB) system under different lubrication regimes, namely, thermohydrodynamic (THD), elastohydrodynamic (EHD), and hybrid lubrication regime. The rotor modeled corresponds to an industrial com...

Ældre betonbroers bæreevne (Load bearing capacity of old concrete bridges)

DEFF Research Database (Denmark)

Nielsen, Anders

1999-01-01

Two old bridges have been analysed in connection with their demolition. The first one is a pedestrian bridge, the Gefion bridge, from 1894. This is the first bridge of reinforced concrete in Denmark. Here the creep in the concrete severely have changed the way in which the load on the bridge was ...... was carried. - The other is a motor way bridge from 1939, which were reinforced 1991 with external steel plates on the areas of shear on the beams. Four beams were carried to our laboratory and load tested. The steel plates have doubled the load bearing capacity of the beams....

Non-destructive radiometry inspection technique for locating reinforcements and void/porosity in bridge bearings

International Nuclear Information System (INIS)

Yahaya bin Jafar; Jaafar bin Abdullah; Mohamad Azmi bin Ismail.

1989-01-01

Defects detection in bridge bearings is very important in controlling quality and safety. Typical manufacturing defects include misalligned or bent steel plates and the presence of voids/porosity within the rubber. A non-destructive radiometry inspection technique was used to locate steel plates position and the presence of voids/porosity in bridge bearing samples provided by the Rubber Research Institute of Malaysia (RRIM). Preliminary studies show that the mentioned defects can readily be determined by this technique. Some of the results are also presented. (author)

A numerical model for design and optimization of surface textures for tilting pad thrust bearings

OpenAIRE

Gropper, Daniel; Harvey, Terence; Wang, Ling

2018-01-01

A numerical model based on the Reynolds equation to study textured tilting pad thrust bearings considering mass-conserving cavitation and thermal effects is presented. A non-uniform and adaptive finite volume method is utilized and two methods are compared and selected regarding their efficiency in handling discontinuities; specifically placing additional nodes closely around discontinuities and directly incorporating discontinuities in the discrete system. Multithreading is applied to improv...

Bearing Capacity Analyses for the Great Belt East Bridge Anchor Blocks

DEFF Research Database (Denmark)

Sørensen, Carsten Steen; Clausen, Carl J. Frimann; Andersen, Henrik

1993-01-01

This paper presents a comparison between different methods of bearing capacity analyses: Upper Bound Method. Limit Equilibrium Analysis and Finite Element Analysis. For the Great Belt East Bridge anchor blocks it was concluded that these methods of calculation agree within 5%. However, for cases ...

Nonlinear Dynamic Response of Compliant Journal Bearings

Directory of Open Access Journals (Sweden)

Glavatskih S.

2012-07-01

Full Text Available This paper investigates the dynamic response of the compliant tilting pad journal bearings subjected to synchronous excitation. Bearing compliance is affected by the properties of pad liner and pad support geometry. Different unbalance eccentricities are considered. It is shown that bearing dynamic response is non-linear. Journal orbit complexity increases with pad compliance though the orbit amplitudes are marginally affected at low loads. At high loads, the journal is forced to operate outside the bearing clearance. The polymer liner reduces the maximum oil film pressure by a factor of 2 when compared to the white metal liner. The nonlinear dynamic response of compliant tilting pad journal bearings is thoroughly discussed.

Fault condition recognition of rolling bearing in bridge crane based on PSO–KPCA

Directory of Open Access Journals (Sweden)

He Yan

2017-01-01

Full Text Available When the rolling bearing in bridge crane gets out of order and often accompanies with occurrence of nonlinear behaviours, its fault information is weak and it is difficult to extract fault features and to distinguish diverse failure modes. Kernel principal component analysis (KPCA may realize nonlinear mapping to solve nonlinear problems. In the paper the particle swarm optimization （PSO）is applied to optimization of kernel function parameter to reduce its bind set-up. The optimal mathematical model of kernel parameters is constructed by means of thought of fisher discriminate functions .And then it is used to bridge crane rolling bearing simulated faults recognition. The simulation results show that KPCA optimized by PSO can effectively classify fault conditions of rolling bearing. It can be concluded that non-linear mapping capability of KPCA after its function parameter by PSO is greatly improved and the KPCA-PSO is very suit for slight and incipient mechanical fault condition recognition.

An alternative to conventional babbitt metal-lined generator pads

Energy Technology Data Exchange (ETDEWEB)

Puuska, H. [Imatra Hydroelectric Power Plant (Finland)

1996-08-01

The generator refurbishment of the Imatra Hydroelectric Power Plant Unit 1 in Finland is described. The generator work called for installation of a new cooling system for the generator thrust bearing. The considerations leading to the decision to replace the conventional babbitt metal-lined pads with elastic metal-plastic coated thrust bearing pads and the installation of the new pads are outlined in the article. Results of the trial run are summarized; the end temperature of the unit was more than 20C lower than for units equipped with conventional babbitted bearings.

Lateral Vibration of Hydroelectric Generating Set with Different Supporting Condition of Thrust Pad

Directory of Open Access Journals (Sweden)

Xiaohui Si

2011-01-01

Full Text Available The variations of the supporting condition, which change the stiffness of tilting pad thrust bearing, may alter the dynamic behavior of the rotor system. The effects of supporting condition of thrust pad on the lateral vibration of a hydroelectric generating set are investigated in this paper. The action of a thrust bearing is described as moments acting on the thrust collar, and the tilting stiffness coefficients of thrust bearing are calculated. A model based on typical beam finite element method is established to calculate the dynamic response, and the effects of supporting conditions such as elastic oil tank support, different heights of the thrust pads with rigid support are discussed. The results reveal that the influence of thrust bearing is small when the elastic oil tanks work normally. When the supporting conditions turn to be rigid due to the oil leakage, the differences of thrust pad heights have evident influence on the load distribution of the thrust pads; while the effects on the tilting stiffness of the thrust bearing and the amplitude of the lateral shaft vibration is small when the maximum load on thrust pads is smaller than the allowable value.

Feedback-Controlled Lubrication for Reducing the Lateral Vibration of Flexible Rotors supported by Tilting-Pad Journal Bearings

DEFF Research Database (Denmark)

Salazar, Jorge Andrés González; Santos, Ilmar

2014-01-01

In this work, the feedback-controlled lubrication regime, based on a model-free designed proportional-derivative (PD) controller, is studied and experimentally tested in a flexible rotor mounted on an actively-lubricated tilting-pad journal bearing (active TPJB). With such a lubrication regime...... to experimentally characterized multi-input multi-output systems is used to determine the stabilizing PD gain domain. The main contribution of this work is to demonstrate the enhancement of the dynamic response of a flexible rotor-bearing system supported by an active TPJB by means of the feedback...... are used as actuators and the flexible rotor lateral movements as feedback control signals. To synthesise the PD controller gains an objective function is optimized in the stabilizing gain domain and then chosen from a subdomain imposed by the servovalves restrictions. The D-decomposition approach expanded...

Bearing assemblies, apparatuses, and motor assemblies using the same

Science.gov (United States)

Sexton, Timothy N.; Cooley, Craig H.; Knuteson, Cody W.

2015-12-29

Various embodiments of the invention relate to bearing assemblies, apparatuses and motor assemblies that include geometric features configured to impart a selected amount of heat transfer and/or hydrodynamic film formation. In an embodiment, a bearing assembly may include a plurality of superhard bearing pads distributed circumferentially about an axis. At least some of the plurality of superhard bearing pads may include a plurality of sub-superhard bearing elements defining a bearing surface. At least some of the plurality of sub-superhard bearing elements may be spaced from one another by one or more voids to impart a selected amount of heat transfer and hydrodynamic film formation thereon during operation. The bearing assembly may also include a support ring that carries the plurality of superhard bearing pads. In addition, at least a portion of the sub-superhard bearing elements may extend beyond the support ring.

Design and fabrication of gas bearings for Brayton cycle rotating unit

Science.gov (United States)

Frost, A.; Tessarzik, J. M.; Arwas, E. B.; Waldron, W. D. (Editor)

1973-01-01

Analysis, design, and testing of two types of pivoted pad journal bearings and a spiral-grooved thrust bearing suitable for direct installation into the NASA 2 to 15 KW Brayton Cycle Rotating Unit (BRU) have been accomplished. Both types of tilting pad bearing assemblies are of the preloaded type, consisting of three pads with one pad flexibly mounted. One type utilizes a non-conforming pivot, while the other replaces the conventional spherical pivot with a cruciform flexible member. The thrust bearing is flexure mounted to accommodate static machine mislinement. Test results indicate that both types of journal bearings should satisfy the requirements imposed by the BRU. Hydrostatic tests of the spiral-grooved thrust bearing showed it to be free of pneumatic hammer with as many as 24 orifices over the BRU pressure and load range.

Geotechnical LFRD calculations of settlement and bearing capacity of GDOT shallow bridge foundations and retaining walls.

Science.gov (United States)

2016-08-09

The AASHTO codes for Load Resistance Factored Design (LRFD) regarding shallow bridge foundations : and walls have been implemented into a set of spreadsheet algorithms to facilitate the calculations of bearing : capacity and footing settlements on na...

Experimental feasibility study of radial injection cooling of three-pad radial air foil bearings

Science.gov (United States)

Shrestha, Suman K.

Air foil bearings use ambient air as a lubricant allowing environment-friendly operation. When they are designed, installed, and operated properly, air foil bearings are very cost effective and reliable solution to oil-free turbomachinery. Because air is used as a lubricant, there are no mechanical contacts between the rotor and bearings and when the rotor is lifted off the bearing, near frictionless quiet operation is possible. However, due to the high speed operation, thermal management is one of the very important design factors to consider. Most widely accepted practice of the cooling method is axial cooling, which uses cooling air passing through heat exchange channels formed underneath the bearing pad. Advantage is no hardware modification to implement the axial cooling because elastic foundation structure of foil bearing serves as a heat exchange channels. Disadvantage is axial temperature gradient on the journal shaft and bearing. This work presents the experimental feasibility study of alternative cooling method using radial injection of cooling air directly on the rotor shaft. The injection speeds, number of nozzles, location of nozzles, total air flow rate are important factors determining the effectiveness of the radial injection cooling method. Effectiveness of the radial injection cooling was compared with traditional axial cooling method. A previously constructed test rig was modified to accommodate a new motor with higher torque and radial injection cooling. The radial injection cooling utilizes the direct air injection to the inlet region of air film from three locations at 120° from one another with each location having three axially separated holes. In axial cooling, a certain axial pressure gradient is applied across the bearing to induce axial cooling air through bump foil channels. For the comparison of the two methods, the same amount of cooling air flow rate was used for both axial cooling and radial injection. Cooling air flow rate was

Assessment of the transportation route of oversize and excessive loads in relation to the load-bearing capacity of existing bridges

Science.gov (United States)

Doležel, Jiří; Novák, Drahomír; Petrů, Jan

2017-09-01

Transportation routes of oversize and excessive loads are currently planned in relation to ensure the transit of a vehicle through critical points on the road. Critical points are level-intersection of roads, bridges etc. This article presents a comprehensive procedure to determine a reliability and a load-bearing capacity level of the existing bridges on highways and roads using the advanced methods of reliability analysis based on simulation techniques of Monte Carlo type in combination with nonlinear finite element method analysis. The safety index is considered as a main criterion of the reliability level of the existing construction structures and the index is described in current structural design standards, e.g. ISO and Eurocode. An example of a single-span slab bridge made of precast prestressed concrete girders of the 60 year current time and its load bearing capacity is set for the ultimate limit state and serviceability limit state. The structure’s design load capacity was estimated by the full probability nonlinear MKP analysis using a simulation technique Latin Hypercube Sampling (LHS). Load-bearing capacity values based on a fully probabilistic analysis are compared with the load-bearing capacity levels which were estimated by deterministic methods of a critical section of the most loaded girders.

Lateral Vibration of Hydroelectric Generating Set with Different Supporting Condition of Thrust Pad

OpenAIRE

Si, Xiaohui; Lu, Wenxiu; Chu, Fulei

2011-01-01

The variations of the supporting condition, which change the stiffness of tilting pad thrust bearing, may alter the dynamic behavior of the rotor system. The effects of supporting condition of thrust pad on the lateral vibration of a hydroelectric generating set are investigated in this paper. The action of a thrust bearing is described as moments acting on the thrust collar, and the tilting stiffness coefficients of thrust bearing are calculated. A model based on typical beam finite element ...

Pad for holding a load against a surface by suction

International Nuclear Information System (INIS)

Farmer, R.C.; Goldsmith, H.A.; Proudlove, M.J.

1981-01-01

This invention concerns suction pads for supporting loads. Specifically, the suction pad is part of a pair of pads located at the ends of a bridge forming a vehicle for transporting instruments for the non-destructive testing of a large vessel intended to contain a fuel assembly for a nuclear reactor immersed in a liquid metal coolant. For example, the vehicle is of the type described in the French patent application filed this day under the heading 'Vehicle for transporting instruments for testing against a wall' [fr

Thermohydrodynamic analysis of cryogenic liquid turbulent flow fluid film bearings, phase 2

Science.gov (United States)

Sanandres, Luis

1994-01-01

The Phase 2 (1994) Annual Progress Report presents two major report sections describing the thermal analysis of tilting- and flexure-pad hybrid bearings, and the unsteady flow and transient response of a point mass rotor supported on fluid film bearings. A literature review on the subject of two-phase flow in fluid film bearings and part of the proposed work for 1995 are also included. The programs delivered at the end of 1994 are named hydroflext and hydrotran. Both codes are fully compatible with the hydrosealt (1993) program. The new programs retain the same calculating options of hydrosealt plus the added bearing geometries, and unsteady flow and transient forced response. Refer to the hydroflext & hydrotran User's Manual and Tutorial for basic information on the analysis and instructions to run the programs. The Examples Handbook contains the test bearing cases along with comparisons with experimental data or published analytical values. The following major tasks were completed in 1994 (Phase 2): (1) extension of the thermohydrodynamic analysis and development of computer program hydroflext to model various bearing geometries, namely, tilting-pad hydrodynamic journal bearings, flexure-pad cylindrical bearings (hydrostatic and hydrodynamic), and cylindrical pad bearings with a simple elastic matrix (ideal foil bearings); (2) improved thermal model including radial heat transfer through the bearing stator; (3) calculation of the unsteady bulk-flow field in fluid film bearings and the transient response of a point mass rotor supported on bearings; and (4) a literature review on the subject of two-phase flows and homogeneous-mixture flows in thin-film geometries.

An air bearing system for small high speed gas turbines

Science.gov (United States)

Turner, A. B.; Davies, S. J.; Nimir, Y. L.

1994-03-01

This paper describes the second phase of an experimental program concerning the application of air bearings to small turbomachinery test rigs and small gas turbines. The first phase examined externally pressurized (EP) journal bearings, with a novel EP thrust bearing, for application to 'warm air' test rigs, and was entirely successful at rotational speeds in excess of 100,000 rpm. This second phase examined several designs of tilting pad-spiring journal bearings, one with a novel form of externally pressurized pad, but all using the original EP thrust bearing. The designs tested are described, including some oscillogram traces, for tests up to a maximum of 70,000 rpm; the most successful using a carbon pad-titanium beam spring arrangement. The thrust bearing which gave trouble-free operation throughout, is also described. The results of an original experiment to measure the 'runway speed' of a radial inflow turbine are also presented, which show that overspeeds of 58 percent above the design speed can result from free-power turbine coupling failure.

ForcePAD And Optimization -

DEFF Research Database (Denmark)

Jonas, Lindemann; Damkilde, Lars

2008-01-01

Design of structures such as bridges, wind turbine wings or mechanical components is a very challenging task and involves both finding the structural layout and analysis of the bearing capacity of the structure. The analysis part is almost always solved by Finite Elements and involves defining a ...

Hydrostatic and hybrid bearing design

CERN Document Server

Rowe, W B

1983-01-01

Hydrostatic and Hybrid Bearing Design is a 15-chapter book that focuses on the bearing design and testing. This book first describes the application of hydrostatic bearings, as well as the device pressure, flow, force, power, and temperature. Subsequent chapters discuss the load and flow rate of thrust pads; circuit design, flow control, load, and stiffness; and the basis of the design procedures and selection of tolerances. The specific types of bearings, their design, dynamics, and experimental methods and testing are also shown. This book will be very valuable to students of engineering des

Recent research and development of bearings for helium circulator

International Nuclear Information System (INIS)

Taniguchi, S.; Ezaki, Z.; Kawaguchi, K.; Matsumura, N.; Kozima, M.

1988-01-01

This paper mainly describes recent studies and successful applications of water lubricated bearing and gas lubricated bearing. Both types of bearing seem to be suitable for a turbo machine installed in an atomic energy plant - such as the helium circulator of a HTGR - not to be affected by radioactivity, so we have been attracted by them for about 10 years. The former was investigated theoretically taking account of turbulent flow due to the low viscosity of water, and compared with the experimental data. Good agreement was obtained, and a successful example applied to a small-sized high speed air compressor is shown. The latter was investigated using a large-sized bearing test rig simulated to an actual machine. The tilting pad journal bearing and the tilting pad thrust bearing were taken and improved for some aspects. These bearings have been taken into service on an actual circulator and are now operating successfully. Currently, a magnetic bearing is being studied to pay special attention to endurance for an earthquake and catcher bearing system. We would like to have an opportunity to present these results in the near future. (author). 5 refs, 15 figs, 2 tabs

Dynamic analysis of 19-span continuous space frame bridge with lead rubber bearings based on vibration tests; 19 keikan renzoku rittai menshinkyo no shindo jikken ni motozuku doteki kaiseki

Energy Technology Data Exchange (ETDEWEB)

Kajikawa, Y.; Fukada, S. [Kanazawa Univ. (Japan); Sugimoto, M.; Hama, H

1998-10-21

The Hanshin/Awaji earthquake disaster caused extensive damage to many bridges of the Hanshin Expressway. N particular, falling-down of superstructures and other destructive damage occurred at Benten Kouku which located in downtown of Kobe. After the earthquake disaster, the continuous 19-span space frame bridge with lead rubber bearings which had approximate 565m bridge length was reconstructed in this region. It is the first trial in Japan to use large lead rubber bearings as an isolator or as a damper at the bottom of the steel pier for the purpose of reduction of seismic force acting on this bridge. As the lead rubber bearings, a spring member was used. In this study, by using jack with a raid releasing mechanism, monotonous loading tests loading statically at the bottom of the pier and rapid releasing tests deloading loads in a moment were carried out. Further, the simulation of the experiment was conducted on the analysis and the analytical model was established in comparison of the experimental data and the analytical data. Using this model, owing to carry out the seismic response analysis, more reliable analytical results were obtained. 22 refs., 24 figs., 3 tabs.

Integrating iPad Technology in Earth Science K-12 Outreach Courses: Field and Classroom Applications

Science.gov (United States)

Wallace, Davin J.; Witus, Alexandra E.

2013-01-01

Incorporating technology into courses is becoming a common practice in universities. However, in the geosciences, it is difficult to find technology that can easily be transferred between classroom- and field-based settings. The iPad is ideally suited to bridge this gap. Here, we fully integrate the iPad as an educational tool into two…

On the future of controllable fluid film bearings

DEFF Research Database (Denmark)

Santos, Ilmar

2011-01-01

lubrication regimes, i.e., as tilting-pad journal bearings, multi-recess journal bearings and plain journal bearings. After a comprehensive overview of the theoretical and experimental technological advancements achieved in university laboratories, the feasibility of industrial applications is highlighted......This work gives an overview of the theoretical and experimental achievements of mechatronics applied to fluid film bearings. Compressible and uncompressible fluids are addressed. Rigid and elastic (deformable) bearing profiles are investigated. Hydraulic, pneumatic, magnetic and piezoelectric...

Dynamic Coefficients of a Tilting Pad With Active Lubrication: Comparison Between Theoretical and Experimental Results

DEFF Research Database (Denmark)

Cerda Varela, Alejandro Javier; Santos, Ilmar

2015-01-01

experimental results from the literature for industrial grade passive tilting pad bearings. This initial validation is followed by a comparison with experimental identification results obtained from a test rig featuring the active bearing design. Good overall agreement is observed in both configurations...

Interaction of Reinforced Elastomeric Bearings in Bridge Construction

Directory of Open Access Journals (Sweden)

Nittmannová Ľubica

2016-03-01

Full Text Available The aim of this paper is to demonstrate the behavior of reinforced elastomeric bearings under various loads. They are made of special types of bearings. The experimental verification of these special bearings has been tested on various types of loading. The results of the experimental measurements are compared with the results of the numerical modeling and calculations according to the standard assumptions in STN EN 1337-3. In the conclusion, the results are summarized for the selected types of bearings.

Measurements versus Predictions for a Hybrid (Hydrostatic Plus Hydrodynamic) Thrust Bearing for a Range of Orifice Diameters

Science.gov (United States)

2010-05-01

Type of Lubrication for a Tilting Pad Thrust Bearing ,” ASME Journal of Lubrication Technology, 96 Ser F (1), pp. 22-27. [9] Gregory, R.S., 1974...1986, “Measurements of Maximum Temperature in Tilting - Pad Thrust Bearings ,” Technical Preprints - Presented at the ASLE 41st Annual Meeting. (ASLE...Safar [7] provides a modified Reynolds number analysis on hydrostatic thrust bearing performance parameters including the effects of tilt . Finally, San

Timber in Bridge Structures

OpenAIRE

Detkin, Viktoria

2016-01-01

The purpose of this final year project was to study the properties of timber as a structural material and the suitability of wood in load bearing members for bridge structures. For a case study, an existing timber bridge was selected. Due to its condition the bridge should be replaced. The design of a new bridge with steel beams holding a glulam deck was made. During the case study the replacement of steel beams by glulam timber ones was discussed. Some calculations were made in order to ...

Experimental and theoretical analysis of a rigid rotor supported by air foil bearings

DEFF Research Database (Denmark)

Larsen, Jon Steffen; Hansen, Asger J. T.; Santos, Ilmar

2015-01-01

The popularity of compressors utilizing foil bearings is increasing. Their mechanical design is challenging, and an accurate prediction of the bearing coefficients is important. A mathematical model taking into account the foil structure, and the detailed geometry of a three pad foil bearing...

Wet adhesion with application to tree frog adhesive toe pads and tires

International Nuclear Information System (INIS)

Persson, B N J

2007-01-01

Strong adhesion between solids with rough surfaces is only possible if at least one of the solids is elastically very soft. Some lizards and spiders are able to adhere (dry adhesion) and move on very rough vertical surfaces due to very compliant surface layers on their attachment pads. Flies, bugs, grasshoppers and tree frogs have less compliant pad surface layers, and in these cases adhesion to rough surfaces is only possible because the animals inject a wetting liquid into the pad-substrate contact area, which generates a relative long-range attractive interaction due to the formation of capillary bridges. In this presentation I will discuss some aspects of wet adhesion for tree frogs and give some comments related to tire applications

Wet adhesion with application to tree frog adhesive toe pads and tires

Energy Technology Data Exchange (ETDEWEB)

Persson, B N J [IFF, FZ-Juelich, 52425 Juelich (Germany)

2007-09-19

Strong adhesion between solids with rough surfaces is only possible if at least one of the solids is elastically very soft. Some lizards and spiders are able to adhere (dry adhesion) and move on very rough vertical surfaces due to very compliant surface layers on their attachment pads. Flies, bugs, grasshoppers and tree frogs have less compliant pad surface layers, and in these cases adhesion to rough surfaces is only possible because the animals inject a wetting liquid into the pad-substrate contact area, which generates a relative long-range attractive interaction due to the formation of capillary bridges. In this presentation I will discuss some aspects of wet adhesion for tree frogs and give some comments related to tire applications.

Thermohydrodynamic analysis of cryogenic liquid turbulent flow fluid film bearings

Science.gov (United States)

Andres, Luis San

1993-01-01

A thermohydrodynamic analysis is presented and a computer code developed for prediction of the static and dynamic force response of hydrostatic journal bearings (HJB's), annular seals or damper bearing seals, and fixed arc pad bearings for cryogenic liquid applications. The study includes the most important flow characteristics found in cryogenic fluid film bearings such as flow turbulence, fluid inertia, liquid compressibility and thermal effects. The analysis and computational model devised allow the determination of the flow field in cryogenic fluid film bearings along with the dynamic force coefficients for rotor-bearing stability analysis.

Rotor Vibration Reduction via Active Hybrid Bearings

DEFF Research Database (Denmark)

Nicoletti, Rodrigo; Santos, Ilmar

2002-01-01

The use of fluid power to reduce and control rotor vibration in rotating machines is investigated. An active hybrid bearing is studied, whose main objective is to reduce wear and vibration between rotating and stationary machinery parts. By injecting pressurised oil into the oil film, through...... orifices machined in the bearing pads, one can alter the machine dynamic characteristics, thus enhancing its operational range. A mathematical model of the rotor-bearing system, as well as of the hydraulic system, is presented. Numerical results of the system frequency response show good agreement...

Journal Bearings

Directory of Open Access Journals (Sweden)

Renato Brancati

1999-01-01

determined after acquiring and analysing the orbits described by the journal axis for assigned unbalance values in different operating conditions. Analysis of the results shows some particular operating features that were not entirely predicted by the theoretical model and which may give rise to malfunctions in the rotor-tilting pad bearings system. The tests were carried out in the rotor dynamics laboratory of the Dipartimento di Ingegneria Meccanica per l'Energetica at the University of Naples.

33 CFR 117.543 - Bear Creek.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bear Creek. 117.543 Section 117.543 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.543 Bear Creek. (a) The draws of the Baltimore...

Field Tests on Hydrodynamic and Hybrid Operation of a Bidirectional Thrust Bearing of a Pump-Turbine

Directory of Open Access Journals (Sweden)

Michał Wasilczuk

2017-12-01

Full Text Available In vertical shaft pump turbines operating in pumped storage power plants an important role is played by a thrust bearing. Due to the bidirectional character of operation, thrust bearing tilting pads have to be supported symmetrically, which is known to be unfavourable from the point of view of their performance. Large thrust bearings have to be carefully designed so as to minimise excessive thermo-elastic pad deformations. The research into fluid film thrust bearings has been quite extensive over the years, comprising theoretical studies of bearing properties with the use of more and more sophisticated calculation codes. On the other hand, the availability of experimental field data on bearing operation is limited, for obvious reasons. In this paper the authors present part of the results of extensive field tests of a large bearing of a pump-turbine they have conducted in a pumped storage power plant. Hopefully this data will be of interest to other researchers to compare theoretical predictions to measurement data.

Numerical research on rotating speed influence and flow state distribution of water-lubricated thrust bearing

International Nuclear Information System (INIS)

Deng Xiao; Deng Liping; Huang Wei

2015-01-01

Water-lubricated thrust bearing is one of the key parts in canned motor pump, for example, the RCP in AP1000, and it functions to balance axial loads. A calculation model which can handle all flow state lubrication performance for water-lubricated thrust bearing has been presented. The model first includes laminar and turbulent Reynolds' equation. Then to get continuous viscosity coefficients cross critical Reynolds number, a transition zone which ranges based on engineering experience is put up, through which Hermite interpolation is employed. The model is numerically solved in finite difference method with uniform grids. To accelerate the calculation process, multigrid method and line relaxation is adopted within the iteration procedure. A medium sized water-lubricated tilting pad thrust bearing is exampled to verify the calculation model. Results suggest that as rotating speed enlarges, lubrication state distribution of the thrust bearing gradually tends to turbulent lubrication from the intersection corner of pad outer diameter and pad inlet to the opposite, minimum water film thickness increases approximately linearly, maximum water film pressure has little change, meanwhile the friction power grows nearly in exponential law which could result in bad effect by yielding much more heat. (author)

Journal and Wave Bearing Impedance Calculation Software

Science.gov (United States)

Hanford, Amanda; Campbell, Robert

2012-01-01

The wave bearing software suite is a MALTA application that computes bearing properties for user-specified wave bearing conditions, as well as plain journal bearings. Wave bearings are fluid film journal bearings with multi-lobed wave patterns around the circumference of the bearing surface. In this software suite, the dynamic coefficients are outputted in a way for easy implementation in a finite element model used in rotor dynamics analysis. The software has a graphical user interface (GUI) for inputting bearing geometry parameters, and uses MATLAB s structure interface for ease of interpreting data. This innovation was developed to provide the stiffness and damping components of wave bearing impedances. The computational method for computing bearing coefficients was originally designed for plain journal bearings and tilting pad bearings. Modifications to include a wave bearing profile consisted of changing the film thickness profile given by an equation, and writing an algorithm to locate the integration limits for each fluid region. Careful consideration was needed to implement the correct integration limits while computing the dynamic coefficients, depending on the form of the input/output variables specified in the algorithm.

Bimetallic ruthenium complexes bridged by divinylphenylene bearing oligo(ethylene glycol)methylether: synthesis, (spectro)electrochemistry and the lithium cation effect.

Science.gov (United States)

Tian, Li Yan; Liu, Yuan Mei; Tian, Guang-Xuan; Wu, Xiang Hua; Li, Zhen; Kou, Jun-Feng; Ou, Ya-Ping; Liu, Sheng Hua; Fu, Wen-Fu

2014-03-14

A series of 1,4-disubstituted ruthenium-vinyl complexes, (E,E)-[{(PMe3)3(CO)ClRu}2(μ-HC=CH-Ar-CH=CH)], in which the 1,4-diethenylphenylene bridge bears two oligo(ethylene glycol)methyl ether side chains at different positions (2,5- and 2,3-positions), were prepared. The respective products were characterized by elemental analyses and NMR spectroscopy. The structures of complexes 1b and 1e were established by X-ray crystallography. The electronic properties of the complexes were investigated by cyclic voltammetry, and IR and UV-vis/NIR spectroscopies. Electrochemical studies showed that the 2,5-substituents better stabilized the mixed-valence states; the electrochemical behavior was greatly affected by lithium cations, especially complex 1g with 2,3-substituents, which was further supported by IR and UV-vis/NIR spectra changes. Spectroelectrochemical studies showed that the redox chemistry was dominated by the non-innocent character of the bridging fragment.

Characteristic Analysis and Simulated Test of Hybrid Bearing with the Introduction of Piezoelectric Controller

Directory of Open Access Journals (Sweden)

Runlin Chen

2016-01-01

Full Text Available A novel hybrid bearing with the introduction of piezoelectric controller and tilting pads to control vibration actively is proposed in this paper, and the feasibility of this scheme is verified by theoretical calculation and experimental data. This scheme can control the vibration of bearing actively by using the electromechanical characteristics of piezoelectric ceramic transducer (PZT components. The static internal character of PZT and static external characteristic of piezoelectric control component are analyzed, and the calculation equations of preload coefficient and driving force of the new bearing are given. The simulation setup of the new bearing is designed and developed. The data representing the relationship of displacement of pad pivot, driving force, voltage, and the simulation stiffness of liquid film are obtained in the test, and the feature parameters of piezoelectric control component are amended to analyze the relationship between preload coefficient of the bearing and driving voltage. The proposed new bearing has the function of controlling preload actively. The theoretical and experimental research results provide essential guidance for the detail design of this new bearing and also provide a new idea for the vibration control of high speed rotor systems.

Bearing development program for a 25 kWe solar-powered organic Rankine-cycle engine

Science.gov (United States)

Nesmith, B.

1985-01-01

The bearing development program is summarized for a 25-kWe power conversion subsystem (PCS) consisting of an organic Rankine-cycle engine, and permanent magnetic alternator (PMA) and rectifier to be used in a 100-kWe point-focusing distributed receiver solar power plant. The engine and alternator were hermetically sealed and used toluene as the working fluid. The turbine, alternator, and feed pump (TAP) were mounted on a single shaft operating at speeds up to 60,000 rev/min. Net thermal-to-electric efficiencies in the range of 21 to 23% were demonstrated at the maximum working fluid temperature of 400 C (750 F). A chronological summary of the bearing development program is presented. The primary causes of bearing wear problems were traced to a combination of rotordynamic instability and electrodynamic discharge across the bearing surfaces caused by recirculating currents from the PMA. These problems were resolved by implementing an externally supplied, flooded-bearing lubrication system and by electrically insulating all bearings from the TAP housing. This program resulted in the successful development of a stable, high-speed, toluene-lubricated five-pad tilting-pad journal bearing and Rayleigh step thrust bearing system capable of operating at all inclinations between horizontal and vertical.

77 FR 5201 - Drawbridge Operation Regulation; Bear Creek, Dundalk, MD

Science.gov (United States)

2012-02-02

...-AA09 Drawbridge Operation Regulation; Bear Creek, Dundalk, MD AGENCY: Coast Guard, DHS. ACTION: Notice... operation of the Baltimore County highway bridge at Wise Avenue across Bear Creek, mile 3.4, between Dundalk... Avenue across Bear Creek, mile 3.4 between Dundalk and Sparrows Point, MD. This change would require the...

Effectiveness of bridge V.A.C. dressings in the treatment of diabetic foot ulcers

Directory of Open Access Journals (Sweden)

Aziz Nather

2011-03-01

Full Text Available Objectives: This is a prospective study of the clinical efficacy of the V.A.C. Granufoam Bridge Dressing for the treatment of diabetic foot ulcers. Materials and methods: Five consecutive patients with diabetic foot ulcers were treated with V.A.C. Granufoam Bridge Dressings and studied over a period of 22–48 days. The indications for treatment included diabetic patients with open ray amputation wounds and wounds post-drainage for abscess with exposed deep structures. Clinical outcome was measured in terms of reduction in wound dimensions, presence of wound granulation, microbial clearance, and development of wound complications. Results: Our results showed that with V.A.C. therapy, wound healing occurred in all patients. The number of dressings required ranged from 8 to 10. The baseline average wound size was 23.1 cm2. Wound areas shrunk by 18.4–41.7%. All subjects achieved 100% wound bed granulation with an average length of treatment of 33 days. Microbial clearance was achieved in all cases. All wounds healed by secondary intention in one case and four cases required split-thickness skin grafting. Conclusion: The V.A.C. Granufoam Bridge Dressing is effective in the treatment of diabetic foot ulcers. It promotes reduction of wound area, wound bed granulation, and microbial clearance. By allowing placement of the suction pad outside the foot, it allowed patients to wear protective shoes and to walk non-weight bearing with crutches during V.A.C. therapy.

Impact Coefficient Analysis of Long-Span Railway Cable-Stayed Bridge Based on Coupled Vehicle-Bridge Vibration

Directory of Open Access Journals (Sweden)

Yongle Li

2015-01-01

Full Text Available Compared with medium and small span bridges, very limited attention has been paid on the research of the impact coefficient of long-span railway bridges. To estimate the impact effects of long-span railway bridges subjected to moving vehicles, a real long-span railway cable-stayed bridge is regarded as the research object in this study, and a coupled model of vehicle-bridge system is established. The track irregularities are taken as the system excitation and the dynamic responses of the vehicle-bridge system are calculated. The impact effects on main girder, stayed cable, bearings, and bridge tower are discussed at various vehicle speeds. The results show that different components of the long-span railway cable-stayed bridge have different impact coefficients. Even for each part, the impact coefficient is also different at different local positions. It reveals that the impact coefficients in the actual situation may have significant differences with the related code clauses in the present design codes.

From Hybrid to Actively-Controlled Gas Lubricated Bearings – Theory and Experiment

DEFF Research Database (Denmark)

Morosi, Stefano

bearings, tilting pad and flexure pivot gas bearings. These solutions proved to be effective in improving static and dynamic properties of the bearings, however issues related to the manufacturing and accuracy of predictions has so far limited their applications. Another drawback is that passive bearings......-rig are backed by a comprehensive mathematical model that couples a finite element model of a flexible rotor, a thermohydrodynamic model based on a modified form of the Reynold’s equation for hybrid aerostatic-aerodynamic lubrication of compressible fluid, a piezoelectric injection system and a proportional...

Seismic Vulnerability Evaluation of a Three-Span Continuous Beam Railway Bridge

Directory of Open Access Journals (Sweden)

Chongwen Jiang

2017-01-01

Full Text Available In order to evaluate the seismic vulnerability of a railway bridge, a nonlinear finite element model of typical three-span continuous beam bridge on the Sichuan-Tibet railway in China was built. It further aimed at performing a probabilistic seismic demand analysis based on the seismic performance of the above-mentioned bridge. Firstly, the uncertainties of bridge parameters were analyzed while a set of finite element model samples were formulated with Latin hypercube sampling method. Secondly, under Wenchuan earthquake ground motions, an incremental dynamic method (IDA analysis was performed, and the seismic peak responses of bridge components were recorded. Thirdly, the probabilistic seismic demand model for the bridge principal components under the prerequisite of two different kinds of bearing, with and without seismic isolation, was generated. Finally, comparison was drawn to further ascertain the effect of two different kinds of bearings on the fragility components. Based on the reliability theory, results were presented concerning the seismic fragility curves.

Dynamic Characteristics of Rotors on Passive and Active Thrust Fluid-film Bearings with Fixed Pads

Directory of Open Access Journals (Sweden)

Babin Alexander

2018-01-01

Full Text Available Application of fluid-film bearings in rotor machines in many cases could have no alternative due to obvious advantages when compared to roller element bearings. Integration of information technology in mechanical engineering resulting in emergence of a new field of research – mechatronic bearings which allowed tracking condition of the most important parts of a machine and adjusting operational parameters of the system. Application of servo valves to control the flow rate through a fluid-film bearing is the most universal and simple way of rotor’s position control due to relative simplicity of modelling and absence of need to radically change the design of conventional hydrodynamic bearings. In the present paper numerical simulations of passive (conventional as opposed to mechatronic and active hybrid thrust fluid-film bearings with a central feeding chamber are presented, that are parts of a mechatronic rotor-bearing node. Numerical model of an active thrust bearing is based on solution of equations of hydrodynamics, rotor dynamics and an additional model of a servo valve. Various types of control have been investigated: P, PI and PID control, and the dynamic behaviour of a system has been estimated under various loads, namely static, periodic and impulse. A design of a test rig has been proposed to study passive and active thrust fluid-film bearings aimed at, among other, validation of numerical results of active bearings simulation.

Numerical Investigation of Turbulence Models for a Superlaminar Journal Bearing

Directory of Open Access Journals (Sweden)

Aoshuang Ding

2018-01-01

Full Text Available With rotating machineries working at high speeds, oil flow in bearings becomes superlaminar. Under superlaminar conditions, flow exhibits between laminar and fully developed turbulence. In this study, superlaminar oil flow in an oil-lubricated tilting-pad journal bearing is analyzed through computational fluid dynamics (CFD. A three-dimensional bearing model is established. CFD results from the laminar model and 14 turbulence models are compared with experimental findings. The laminar simulation results of pad-side pressure are inconsistent with the experimental data. Thus, the turbulence effects on superlaminar flow should be considered. The simulated temperature and pressure distributions from the classical fully developed turbulence models cannot correctly fit the experimental data. As such, turbulence models should be corrected for superlaminar flow. However, several corrections, such as transition correction, are unsuitable. Among all the flow models, the SST model with low-Re correction exhibits the best pressure distribution and turbulence viscosity ratio. Velocity profile analysis confirms that a buffer layer plays an important role in the superlaminar boundary layer. Classical fully developed turbulence models cannot accurately predict the buffer layer, but this problem can be resolved by initiating an appropriate low-Re correction. Therefore, the SST model with low-Re correction yields suitable results for superlaminar flows in bearings.

Showing one of the air-pads applications used in CMS, for big loads translations in civil ingeneering.

CERN Multimedia

Petiot Pascal

2000-01-01

A 2500 Tons concrete bridge was shown in Germany during its installation on place.It use an air pads system on special rails like CMS experiment will do at the Pt.5 LHC site. A 30 meters lenght displacement and less than a millimeter acuracy.

The effect of inertia force in water lubricated thrust bearings of canned reactor coolant pump

International Nuclear Information System (INIS)

Deng Liping

1994-01-01

The water lubricated thrust bearings are analyzed. According to characteristic of low viscosity of water the lubricated equation for design and calculation of water lubricated thrust bearings is established. The calculation and analyses show that the effect of inertia force in water lubricated thrust bearings should not be neglected except the conditions of low speed, high angle of inclination and low radius ratio of pad

iPad portable genius

CERN Document Server

McFedries, Paul

2013-01-01

Make the most of your iPad with these savvy tips and techniques The iPad, iPad Air, and iPad mini are taking the world by storm. This no-nonsense guide covers everything you want to know to take full advantage of all your iPad has to offer. Along with necessary basics about the newest iPad; iPad Air, iPad mini; and iOS; it gives you smart; innovative ways to accomplish a variety of tasks and tips to help you maximize the convenience of your Apple digital lifestyle. More than 100 million iPads have been sold; and the number continues to growHip and practical; Portable Genius guides are packed

Stålplader gav dobbelt bæreevne (Steel plates doubled the load bearing capacity)

DEFF Research Database (Denmark)

Nielsen, Jan Broch

1999-01-01

Abstract from an examination of motor road bridge beams reinforced with steel plates on the sides and bottom. The plates doubled the load bearing capacity of the beams.......Abstract from an examination of motor road bridge beams reinforced with steel plates on the sides and bottom. The plates doubled the load bearing capacity of the beams....

iPad for the older and wiser get up and running with your Apple iPad, iPad Air and iPad Mini

CERN Document Server

McManus, Sean

2013-01-01

Apple's iPad puts a limitless world of entertainment, communication, and everyday functionality in the palms of your hands. iPad for the Older and Wiser, 4th Edition quickly teaches you how to make the most of your new gadget with easy-to-follow instructions. Fully updated to include the iPad Air and iOS 7, this step-by-step guide shows you exactly how to set up your device and discover what it can do - all in jargon-free language. Learn how to: Set up your iPad and copy music and photos from your computerKeep in touch with email and messagesBrowse the web and shop onlineHave video chats wi

Seismic tipping analysis of a spent nuclear fuel shipping cask sitting on a crush pad

International Nuclear Information System (INIS)

Uldrich, E.D.; Hawkes, B.D.

1998-04-01

A crush pad has been designed and analyzed to absorb the kinetic energy of an accidentally dropped spent nuclear fuel shipping cask into a 44 ft. deep cask unloading pool. Conventional analysis techniques available for evaluating a cask for tipping due to lateral seismic forces assume that the cask rests on a rigid surface. In this analysis, the cask (110 tons) sits on a stainless steel encased (0.25 in. top plate), polyurethane foam (4 ft. thick) crush pad. As the cask tends to rock due to horizontal seismic forces, the contact area between the cask and the crush pad is reduced, increasing the bearing stress, and causing the pivoting corner of the cask to depress into the crush pad. As the crush pad depresses under the cask corner, the pivot point shifts from the corner toward the cask center, which facilitates rocking and potential tipping of the cask. Subsequent rocking of the cask may deepen the depression, further contributing to the likelihood of cask tip over. However, as the depression is created, the crush pad is absorbing energy from the rocking cask. Potential tip over of the cask was evaluated by performing a non-linear, dynamic, finite element analysis with acceleration time history input. This time history analysis captured the effect of a deforming crush pad, and also eliminated conservatisms of the conventional approaches. For comparison purposes, this analysis was also performed with the cask sitting on a solid stainless steel crush pad. Results indicate that the conventional methods are quite conservative relative to the more exacting time history analysis. They also indicate that the rocking motion is less on the foam crush pad than on the solid stainless steel pad

Impacts of iPad attributes, Lifestyles and media dependency on adoption of iPad and intensity of iPad usage in Mainland China

OpenAIRE

Kevin, Li Xinpeng

2012-01-01

The goal of this exploratory research is to identify attributes that can distinctly characterize iPad and examine the predictive power of iPad attributes, lifestyles, media dependency, and demographics on adoption of iPad, iPad usage patterns and intensity of iPad usage. Using a snowballing sample, an online survey was conducted with 623 university students in Mainland China, among which 217 were iPad users and 406 were non-users. Results of regression analyses show that application affordanc...

iPad Made Simple

CERN Document Server

Trautschold, Martin; Learning, MSL Made Simple

2010-01-01

The new iPad is sleek, powerful, and most importantly, it's much more than just a big iPhone. Your iPad is can be used for reading, surfing the web, emailing, watching TV/Movies, getting work done, and much more. And with the upcoming wave of iPad apps, the possibilities are endless. iPad X Made Simple clarifies all of the key features on the iPad, introduces what's new, and also reveals dozens of time-saving shortcuts and techniques. The book has over 1,000 screen shots that are carefully annotated with step-by-step instructions. * Clear instructions on how to set up and use the iPad * Illust

PsyPad: a platform for visual psychophysics on the iPad.

Science.gov (United States)

Turpin, Andrew; Lawson, David J; McKendrick, Allison M

2014-03-11

This article introduces PsyPad, a customizable, open-source platform for configuring and conducting visual psychophysics experiments on iPads without the need for any code development for the iPad. Stimuli for experiments are created off-line as a library of images. The PsyPad app (obtainable from the Apple App Store) presents the images according to either built-in, customizable staircase or method of constant stimuli procedures, mapping stimuli levels to images based on the image file names. On-screen buttons for responses are configurable and matched to "correct" using the image file name of any given stimulus. All actions are logged into a text file and sent to a specified server at the end of the test if an Internet connection is available. If the iPad is not connected, the results are uploaded the next time the iPad is online. We provide a secure server for this purpose, but the server-side software is also open source if researchers choose to run their own server.

Numerical investigation of the bearing capacity of transversely prestressed concrete deck slabs

NARCIS (Netherlands)

Amir, S.; Van der Veen, C.; Walraven, J.C.; De Boer, A.

2014-01-01

The research subject of this paper is the bearing capacity of transversely prestressed concrete bridge decks between concrete girders under concentrated loads. Experiments on a 1:2 scale model of this bridge were carried out in the laboratory and a 3D nonlinear finite element model was developed in

TypePad For Dummies

CERN Document Server

Nelson, Melanie

2010-01-01

TypePad for Dummies will be on guiding readers through the technical tasks necessary for starting, using and customizing a TypePad blog. It will comprehensively explain choosing the right TypePad membership plan, singing up, configuring, using and customizing a blog using the TypePad system. It will also include: Illustrations from real-world blogs with screenshots and specific examples that bring the book's concepts and ideas to life.; Step-by-step tutorials that will walk readers through the process of signing up for a new TypePad blog and getting down the business of publishing their conten

Study on load test of 100m cross-reinforced deck type concrete box arch bridge

Science.gov (United States)

Shi, Jing Xian; Cheng, Ying Jie

2018-06-01

Found in the routine quality inspection of highway bridge that many vertical fractures on the main beam (10mT beam) of the steel reinforced concrete arch bridge near the hydropower station. In order to grasp the bearing capacity of this bridge under working conditions with cracks, the static load and dynamic load test of box arch bridge are carried out. The Midas civil theory is calculated by using the special plate trailer - 300 as the calculation load, and the deflection and stress of the critical section are tested by the equivalent cloth load in the test vehicle. The pulsation test, obstacles and no obstacle driving test were carried out. Experimental results show that the bridge under the condition of the test loads is in safe condition, main bearing component of the strength and stiffness meet the design requirements, the crack width does not increase, in the process of loading bridge overall work performance is good.

Control system design for flexible rotors supported by actively lubricated bearings

DEFF Research Database (Denmark)

Nicoletti, Rodrigo; Santos, Ilmar

2008-01-01

and keeping the lengths of the two eigenvalues constant in the real-imaginary plane. The methodology is applied to an industrial gas compressor supported by active tilting-pad journal bearings. The unbalance response functions and mode shapes of the flexible rotor with and without active control are presented...

iPad Portable Genius

CERN Document Server

McFedries, Paul

2010-01-01

Everything everyone wants to know about using the Apple iPad. On January 27, 2010, Apple announced the latest in its line of revolutionary, ultraportable devices - the iPad. iPad Portable Genius is the latest in a line of ultra handy, go-to and goes-with you anywhere guides for getting the most out of a new Apple product. Written to provide readers with highly useful information that's easily accessible, iPad Portable Genius is full of tips, tricks and techniques for maximizing each of the iPad's most popular features.:; Designed in full-color with an Apple look and feel, and written in a hip,

Monitoring Bridge Dynamic Responses Using Fiber Bragg Grating Tiltmeters.

Science.gov (United States)

Xiao, Feng; Chen, Gang S; Hulsey, J Leroy

2017-10-20

In bridge health monitoring, tiltmeters have been used for measuring rotation and curvature; however, their application in dynamic parameter identification has been lacking. This study installed fiber Bragg grating (FBG) tiltmeters on the bearings of a bridge and monitored the dynamic rotational angle. The dynamic features, including natural frequencies and mode shapes, have been identified successfully. The innovation presented in this paper is the first-time use of FBG tiltmeter readings to identify the natural frequencies of a long-span steel girder bridge. The identified results have been verified using a bridge finite element model. This paper introduces a new method for the dynamic monitoring of a bridge using FBG tiltmeters. Limitations and future research directions are also discussed in the conclusion.

Monitoring Bridge Dynamic Responses Using Fiber Bragg Grating Tiltmeters

Directory of Open Access Journals (Sweden)

Feng Xiao

2017-10-01

Full Text Available In bridge health monitoring, tiltmeters have been used for measuring rotation and curvature; however, their application in dynamic parameter identification has been lacking. This study installed fiber Bragg grating (FBG tiltmeters on the bearings of a bridge and monitored the dynamic rotational angle. The dynamic features, including natural frequencies and mode shapes, have been identified successfully. The innovation presented in this paper is the first-time use of FBG tiltmeter readings to identify the natural frequencies of a long-span steel girder bridge. The identified results have been verified using a bridge finite element model. This paper introduces a new method for the dynamic monitoring of a bridge using FBG tiltmeters. Limitations and future research directions are also discussed in the conclusion.

Existence of equilibria in articulated bearings

Science.gov (United States)

Buscaglia, G.; Ciuperca, I.; Hafidi, I.; Jai, M.

2007-04-01

The existence of equilibrium solutions for a lubricated system consisting of an articulated body sliding over a flat plate is considered. Though this configuration is very common (it corresponds to the popular tilting-pad thrust bearings), the existence problem has only been addressed in extremely simplified cases, such as planar sliders of infinite width. Our results show the existence of at least one equilibrium for a quite general class of (nonplanar) slider shapes. We also extend previous results concerning planar sliders.

Teaching with iPads

Science.gov (United States)

Maj, Hubert

2015-04-01

Bilingual students in high school with bilingual units in Boguchwała have received iPads for learning English and a few subjects using CLIL (biology, basics of entrepreneurship, geography, IT and mathematics). Lessons with iPads are interesting for students for several reasons. First of all, teenagers like new technologies and using iPads for teaching helps students to learn by fun. Secondly, iPads give new possibilities of looking for knowledge about each theme. Moreover, teaching with iPads develops students' engagement. They have a chance to choose a few among over 65 000 applications for gathering and then presenting information about the lesson topic. They can easily prepare presentations, movies, cartoons, mind maps or whatever they like. Teaching students, thanks to the iPads, makes it their initiative, and the teacher can inspire them to look for the knowledge rather than disciplining pupils. But teaching with iPads is connected with many problems. For instance, there are not any examples on how to teach using these tools. It is very up-to-date technology and teachers firstly must learn the possibilities of iPads and look for new applications. It takes much time, especially at the beginning, and is difficult especially for inexperienced teachers. In addition, it is almost impossible to maintain control of the iPads for all of the students during the lesson. They can use their iPads for something unconnected with the topic of the lesson. Thirdly is lack of time - active methods (with iPads as well) are more time-consuming and it could be that they do not finish the whole program. And of course the last, but not at least, is the problem of money. Some of the applications must be paid for, and it is usually obligatory to possess a credit card. Fortunately, it is not expensive - applications usually cost a few euros and many of them are free and really good.

Teach yourself visually iPad

CERN Document Server

Hart-Davis, Guy

2013-01-01

Fully updated coverage on the latest iPad and iPad mini! As the amazing iPad continues to evolve, so does this invaluable visual guide. Bestselling veteran author Guy Hart-Davis gets you up to date on the latest generation of the iPad, the new iPad Air, as well as the iPad mini with his clear step-by-step, image-driven guidance that is perfectly geared towards those who learn best with visual assistance. You'll get all the latest information for accessing and downloading books, apps, music, and video content as well as sending photos and e-mails, syncing with other devices and services, and

Multi-Hazard Assessment of Scour Damaged Bridges with UAS-Based Measurements

Science.gov (United States)

Özcan, O.; Ozcan, O.

2017-12-01

Flood and stream induced scour occurring in bridge piers constructed on rivers is one of the mostly observed failure reasons in bridges. Scour induced failure risk in bridges and determination of the alterations in bridge safety under seismic effects has the ultimate importance. Thus, for the determination of bridge safety under the scour effects, the scour amount under bridge piers should be designated realistically and should be tracked and updated continuously. Hereby, the scour induced failures in bridge foundation systems will be prevented and bridge substructure design will be conducted safely. In this study, in order to measure the amount of scour in bridge load bearing system (pile foundations and pile abutments) and to attain very high definition 3 dimensional models of river flood plain for the flood analysis, unmanned aircraft system (UAS) based measurement methods were implemented. UAS based measurement systems provide new and practical approach and bring high precision and reliable solutions considering recent measurement systems. For this purpose, the reinforced concrete (RC) bridge that is located on Antalya Boğaçayı River, Turkey and that failed in 2003 due to flood-induced scour was selected as the case study. The amount of scour occurred in bridge piers and piles was determined realistically and the behavior of bridge piers under scour effects was investigated. Future flood effects and the resultant amount of scour was determined with HEC-RAS software by using digital surface models that were obtained at regular intervals using UAS for the riverbed. In the light of the attained scour measurements and expected scour after a probable flood event, the behavior of scour damaged RC bridge was investigated by pushover and time history analyses under lateral and vertical seismic loadings. In the analyses, the load and displacement capacity of bridge was observed to diminish significantly under expected scour. Thus, the deterioration in multi hazard

Research on Bored Bearing Characteristics in Xi’an

Directory of Open Access Journals (Sweden)

Zhang Lipeng

2015-01-01

Full Text Available To analyze the influence of different soil properties on pile foundation load-bearing characteristics, taking a section of railway in Xi’an and a bridge of Xi’an as test area, and by field static load test to study load transfer characteristics after the test piles under axial pressure, including the distribution of axial force, pile lateral friction, tip resistance traits, ultimate bearing capacity determine, and compare with the theory bearing capacity. Experimental results show that, adjacent soil properties change large, axial force and lateral friction mutation at the junction of corresponding soil layer. Silty clay in different parts is below ground, and its lateral friction plays much difference. Pile lateral friction plays an important role in bearing capacity, but the role of round gravel soil end bearing capacity to pile bearing capacity can’t be ignored. Tests calculate pile bearing capacity significantly larger than standardized formula calculation bearing capacity, which are respectively 55.35% and 119.1%. And give the similar project condition the suggested values of pile bearing capacity and soil friction, to provide reference for similar pile foundation design.

Mechatronics Applied to Fluid Film Bearings: Towards More Efficient Machinery

DEFF Research Database (Denmark)

Cerda Varela, Alejandro Javier

the machine is defined as a mechatronic system. This integrated approach comprises the usage of machine elements capable of modifying their characteristics, by using in a combined way mechanical elements, sensors, processing units and actuators. The research project entitled "Mechatronics Applied to Fluid......The current trends regarding turbomachinery design and operation demand for an expansion of the operational boundaries of these mechanical systems, regarding production rate, reliability and adaptability. In order to face the new requirements, it is necessary to migrate towards a new concept, where...... Film Bearings: Towards more Efficient Machinery" was aimed at improving the state of the art regarding the usage of fluid film bearings as "smart" machine elements. Specifically, this project dealt with a tilting pad journal bearing design that features a controllable lubrication system, capable...

Modal analysis of cable-stayed UHPC bridge

Directory of Open Access Journals (Sweden)

Tej Petr

2017-01-01

Full Text Available This paper deals with the dynamic analysis of cable-stayed UHPC bridge over the Vltava river near town Melnik in Czech Republic, Europe. Bridge serves for pedestrians and cyclists. This work aims to familiarize the reader with dynamic calculations carried out and the results obtained, describing the dynamic properties of proposed bridge. The construction of bridge is designed as a cable-stayed structure with prestressed bridge deck consisting of prefabricated UHPC panels and reversed “V” shaped steel pylon with height of approximately 40 meters. The deck is anchored using 24 steel hangers in one row in a steel pylon - 17 ropes in the main span and 7 cables on the other side. Range of the main span is 99.18 meters and the secondary span is 31.9 m. Deck width is 4.5 meters with 3.0 meters passing space. The bridge is designed for the possibility of passage of vehicles weighting up to 3.5 tonnes. Deck panels are made of UHPC with reinforcement. At the edge of the bridge on the side of the shorter span the bridge deck is firmly connected with abutment and on the other deck it is stored using a pair of sliding bearings.

Abdominal wall fat pad biopsy

Science.gov (United States)

Amyloidosis - abdominal wall fat pad biopsy; Abdominal wall biopsy; Biopsy - abdominal wall fat pad ... is the most common method of taking an abdominal wall fat pad biopsy . The health care provider cleans the ...

Measurement and evaluation of EDM bearing currents by the normalized Joule integral

International Nuclear Information System (INIS)

Vidmar, Gregor; Miljavec, Damijan; Agrež, Dušan

2014-01-01

Apparent current density is the most common criterion used in literature to estimate bearing endangerment due to bearing currents. In the paper, a new criterion called the normalized Joule integral is proposed as a more reliable and accurate one. This approach is more general and gives good correlation between current in the bypass bridge and bearing current. Furthermore, it considers the whole current that causes bearing damage, not just its peak value. The choice of the normalized Joule integral is theoretically explained and supported by measurements and simulations. The levels of bearing endangerment related to the normalized Joule integral of bearing currents are estimated. (paper)

Effectiveness of Tuned Mass Dampers in Seismic Response Control of Isolated Bridges Including Soil-Structure Interaction

Directory of Open Access Journals (Sweden)

Said Elias

Full Text Available Abstract The effect of soil-structure interaction (SSI on the dynamic responses of seismically isolated three-span continuous reinforced concrete (RC bridge is investigated. Also, tuned mass damper(s (TMD/s is/are installed to control undesirable bearing displacement, even under the SSI effect. The TMDs are placed at the mid-span of the bridge and each tuned with a modal frequency, while controlling up to first few modes as desirable. The soil surrounding the foundation of pier is modeled by frequency independent coefficients. Dynamic analysis is carried out in time domain using direct integration method. In order to specify the effects of the SSI, the responses of the non-isolated, isolated, and controlled isolated bridge are compared. It is observed that the soil surrounding the pier has significant effects on the bearing displacement of the isolated RC bridges. In addition, it is observed that the seismic responses of isolated RC bridge reduced significantly with installation of the TMDs.

Oil-free bearing development for high-speed turbomachinery in distributed energy systems – dynamic and environmental evaluation

Directory of Open Access Journals (Sweden)

Tkacz Eliza

2015-09-01

Full Text Available Modern distributed energy systems, which are used to provide an alternative to or an enhancement of traditional electric power systems, require small size highspeed rotor turbomachinery to be developed. The existing conventional oil-lubricated bearings reveal performance limits at high revolutions as far as stability and power loss of the bearing are concerned. Non-conventional, oil-free bearings lubricated with the machine working medium could be a remedy to this issue. This approach includes a correct design of the machine flow structure and an accurate selection of the bearing type. Chosen aspects of the theoretical and experimental investigations of oil-free bearings and supports; including magnetic, tilting pad, pressurized aerostatic and hydrostatic bearings as well as some applications of oil-free bearing technology for highspeed turbomachinery; are described in the paper.

When, where and how the bridge breaks: anaphase bridge breakage plays a crucial role in gene amplification and HSR generation

International Nuclear Information System (INIS)

Shimizu, Noriaki; Shingaki, Kenta; Kaneko-Sasaguri, Yukiko; Hashizume, Toshihiko; Kanda, Teru

2005-01-01

Amplified genes are frequently localized on extrachromosomal double minutes (DMs) or in chromosomal homogenously staining regions (HSRs). We previously showed that a plasmid bearing a mammalian replication initiation region could efficiently generate DMs and HSRs after transfection into human tumor cell lines. The Breakage-Fusion-Bridge (BFB) cycle model, a classical model that explains how HSRs form, could also be used to explain how the transfected plasmids generate HSRs. The BFB cycle model involves anaphase bridge formation due to the presence of dicentric chromosomes, followed by the breakage of the bridge. In this study, we used our plasmid-based model system to analyze how anaphase bridges break during mitosis. Dual-color fluorescence in situ hybridization analyses revealed that anaphase bridges were most frequently severed in their middle irrespective of their lengths, which suggests that a structurally fragile site exists in the middle of the anaphase bridge. Breakage of the chromosomal bridges occurred prior to nuclear membrane reformation and the completion of cytokinesis, which indicates that mechanical tension rather than cytokinesis is primarily responsible for severing anaphase bridges. Time-lapse observation of living cells revealed that the bridges rapidly shrink after being severed. If HSR length was extended too far, the bridge could no longer be resolved and became tangled depending on the tension. The unbroken bridge appeared to inhibit the completion of cytokinesis. These observations strongly suggest that anaphase bridges are highly elastic and that the length of the spindle axis determines the maximal HSR length

Effects of Irregular Bridge Columns and Feasibility of Seismic Regularity

Science.gov (United States)

Thomas, Abey E.

2018-05-01

Bridges with unequal column height is one of the main irregularities in bridge design particularly while negotiating steep valleys, making the bridges vulnerable to seismic action. The desirable behaviour of bridge columns towards seismic loading is that, they should perform in a regular fashion, i.e. the capacity of each column should be utilized evenly. But, this type of behaviour is often missing when the column heights are unequal along the length of the bridge, allowing short columns to bear the maximum lateral load. In the present study, the effects of unequal column height on the global seismic performance of bridges are studied using pushover analysis. Codes such as CalTrans (Engineering service center, earthquake engineering branch, 2013) and EC-8 (EN 1998-2: design of structures for earthquake resistance. Part 2: bridges, European Committee for Standardization, Brussels, 2005) suggests seismic regularity criterion for achieving regular seismic performance level at all the bridge columns. The feasibility of adopting these seismic regularity criterions along with those mentioned in literatures will be assessed for bridges designed as per the Indian Standards in the present study.

iPad 2 Made Simple

CERN Document Server

Mazo, Gary; Ritchie, Rene

2011-01-01

The iPad 2 is thinner, more powerful, intuitive and very fun for users of all ages. Your iPad can be used for reading, surfing the web, emailing, watching TV and movies, getting work done and much more. And with over 65,000 apps just for the iPad, as well as the ability to run over 30,000 iPhone apps, the possibilities are endless. iPad 2 Made Simple clarifies all of the key features on the iPad, introduces what's new, and also reveals dozens of time-saving shortcuts and techniques. The book has over 1,000 screen shots that are carefully annotated with step-by-step instructions. * Clear instru

The Chevron Foil Thrust Bearing: Improved Performance Through Passive Thermal Management and Effective Lubricant Mixing

Science.gov (United States)

Bruckner, Robert

2013-01-01

An improved foil thrust bearing is described that eliminates or reduces the need for forced cooling of the bearing foils while at the same time improves the load capacity of the bearing, enhances damping, provides overload tolerance, and eliminates the high speed load capacity drop-off that plagues the current state of the art. The performance improvement demonstrated by the chevron foil thrust bearing stems from a novel trailing edge shape that splays the hot lubricant in the thin film radially, thus preventing hot lubricant carry-over into the ensuing bearing sector. Additionally, the chevron shaped trailing edge induces vortical mixing of the hot lubricant with the gas that is naturally resident within the inter-pad region of a foil thrust bearing. The elimination of hot gas carry-over in combination with the enhanced mixing has enabled a completely passive thermally managed foil bearing design. Laboratory testing at NASA has confirmed the original analysis and reduced this concept to practice.

On the Performance of Super-Long Integral Abutment Bridges: Parametric Analyses and Design Optimization

OpenAIRE

Lan, Cheng

2012-01-01

The concept of "integral abutment bridge" has recently become a topic of remarka-ble interest among bridge engineers, not only for newly built bridges but also during refurbishment processes. The system constituted by the substructure and the superstructure can achieve a composite action responding as a single structural unit; the elimination of expansion joint and bearings on the abutments, greatly reduce the construction and maintenance costs. To maximize the benefits from integral abutment...

Lifecycle Assessments of Railway Bridge Transitions Exposed to Extreme Climate Events

Directory of Open Access Journals (Sweden)

Sadudee Setsobhonkul

2017-06-01

Full Text Available Railway track components located at bridge transition zones or approach areas suffer from impact load and vibrations caused by abrupt changes in track stiffness on the bridge and the subgrade. The numerous strategies that can be used to mitigate these abrupt track stiffness changes rely on one of two concepts. The first concept is that of providing a gradual stiffness change, and the second is that of equalizing the track stiffness. A number of such mitigation methods have been developed and implemented over recent decades. Construction activities associated with these methods require various materials, processes, and uses of time, costs, and carbon emissions. In this study, eight of the most common techniques for railway bridge transition mitigation, including under ballast mats (UBMs, soft baseplates, under sleeper pads (USPs, rail pads, embankment treatments, transition slabs, ballast bonding, and wide sleepers, are compared. This study benchmarks the costs and carbon emissions of these eight mitigation techniques over the 50-year lifespan of a railway system subject to identical probabilities of four environmental scenarios: a control case, extremely high temperatures, extremely low temperatures, and flash flooding. This unprecedented study systemically investigates the effectiveness of the mitigation methods while considering the effects of 30 and 100 m bridge span lengths. Our results indicate that railway engineers should adopt different mitigation methods for different scenarios. The soft baseplate is the most appropriate method for a short-span bridge in the control case and the case of flash flooding, while ballast bonding is better for long-span railway bridges. Embankment treatment is recommended for both high- and low-extreme temperatures. However, its applicability is limited when the differential track stiffness is extremely high. Hence, alternatives that are 5–25% more expensive are proposed in parallel. The alternative

Treating P.A.D.

Science.gov (United States)

... Issue Past Issues Special Section Treating P.A.D. Past Issues / Summer 2008 Table of Contents For ... Illustration courtesy of NHLBI Treatment for P.A.D. is designed to reduce a patient's symptoms, prevent ...

Functionally different pads on the same foot allow control of attachment: stick insects have load-sensitive "heel" pads for friction and shear-sensitive "toe" pads for adhesion.

Directory of Open Access Journals (Sweden)

David Labonte

Full Text Available Stick insects (Carausius morosus have two distinct types of attachment pad per leg, tarsal "heel" pads (euplantulae and a pre-tarsal "toe" pad (arolium. Here we show that these two pad types are specialised for fundamentally different functions. When standing upright, stick insects rested on their proximal euplantulae, while arolia were the only pads in surface contact when hanging upside down. Single-pad force measurements showed that the adhesion of euplantulae was extremely small, but friction forces strongly increased with normal load and coefficients of friction were [Formula: see text] 1. The pre-tarsal arolium, in contrast, generated adhesion that strongly increased with pulling forces, allowing adhesion to be activated and deactivated by shear forces, which can be produced actively, or passively as a result of the insects' sprawled posture. The shear-sensitivity of the arolium was present even when corrected for contact area, and was independent of normal preloads covering nearly an order of magnitude. Attachment of both heel and toe pads is thus activated partly by the forces that arise passively in the situations in which they are used by the insects, ensuring safe attachment. Our results suggest that stick insect euplantulae are specialised "friction pads" that produce traction when pressed against the substrate, while arolia are "true" adhesive pads that stick to the substrate when activated by pulling forces.

Influence of surface texturing on the performance of tilting pad thrust bearings

OpenAIRE

Gropper, Daniel; Wang, Ling; Harvey, Terry J.; Meck, Klaus-Dieter; Gviniashvili, Vladimir

2016-01-01

Surface textures have been shown to have the potential of enhancing the performance of hydrodynamic bearings and many other applications. However, a comprehensive literature review by the authors has revealed that the application of surface texturing is still limited due to major challenges, such as the complexity of computational models and the large variety of operating conditions encountered in conventional industrial applications. In the present work, the potential of surface texturing fo...

iPad for digital photographers

CERN Document Server

Story, Derrick

2013-01-01

Discover innovative ways to strengthen your photography business with your iPad Many photographers are turning to the flexible, easy-to-use tools of the iPad and relying on them to wear a variety of hats in their photography business. Whether portable portfolio, editing tool, payment-tracking system, or appointment calendar, the iPad melds together the best attributes of the cell phone and a laptop computer and this unique book highlights them all. With this helpful resource, you'll learn how to get the most out of your iPad to not only improve your business but also enhance your p

iPad mini for dummies

CERN Document Server

Baig, Edward C

2014-01-01

Find out why the iPad mini has never been bigger This new edition of iPad mini For Dummies covers all the latest tips and tricks for getting an even bigger bang out of your iPad mini. Presented in full-color and written in the straightforward but fun language that has defined the For Dummies brand for more than twenty years, this friendly guide walks you through the multitouch interface, going online, getting connected, packing your iPad mini with apps, games, e-books, photos, music, and movies, synchronizing your data, texting with iMessage, working with Siri, importing pictures and launching

Beginning iPad Application Development

CERN Document Server

Lee, Wei-Meng

2010-01-01

A hands-on approach to iPad application development. Beginning iPad Application Development is written to help jumpstart beginning iPad developers. It covers the various topics in such a manner that you will progressively learn without being overwhelmed by the details. It adopts the philosophy that the best way to learn is by doing, hence the numerous Try It Out sections in all the chapters, which first show you how to build something and then explain how things work. Although iPad programming is a huge topic, the aim for this book is to get you started with the fundamentals, and help you unde

iPad & Siri for dummies

CERN Document Server

Baig, Edward C

2012-01-01

Two complete e-books on using iPad and Siri for one low price! This unique value-priced e-book set brings together two bestselling For Dummies books in a single e-book file. Including a comprehensive table of contents and the full text of each book, complete with cover, this e-book set helps you get the most out of your iPad and Siri, its artificial intelligence personal assistant. Best of all, you'll pay less than the cost of each book purchased separately. You'll get the complete text of: iPad For Dummies, which helps you toSet up your iPad, browse the

Activation of PAD4 in NET formation

Directory of Open Access Journals (Sweden)

Amanda eRohrbach

2012-11-01

Full Text Available Peptidyl arginine deiminases, or PADs, convert arginine residues to the non-ribosomally encoded amino acid citrulline in a variety of protein substrates. PAD4 is expressed in granulocytes and is essential for the formation of neutrophil extracellular traps (NETs via PAD4-mediated histone citrullination. Citrullination of histones is thought to promote NET formation by inducing chromatin decondensation and facilitating the expulsion of chromosomal DNA that is coated with antimicrobial molecules. Numerous stimuli have been reported to lead to PAD4 activation and NET formation. However, how this signaling process proceeds and how PAD4 becomes activated in cells is largely unknown. Herein, we describe the various stimuli and signaling pathways that have been implicated in PAD4 activation and NET formation, including the role of reactive oxygen species generation. To provide a foundation for the above discussion, we first describe PAD4 structure and function, and how these studies led to the development of PAD-specific inhibitors. A comprehensive survey of the receptors and signaling pathways that regulate PAD4 activation will be important for our understanding of innate immunity, and the identification of signaling intermediates in PAD4 activation may also lead to the generation of pharmaceuticals to target NET-related pathogenesis.

Structural Performance Evaluation of Tsing MA Bridge Deck Using Long-Term Monitoring Data

Science.gov (United States)

Ni, Y. Q.; Xia, H. W.; Ko, J. M.

The Tsing Ma Bridge in Hong Kong is suspension bridge with a main span of 1377 m carrying both highway and railway traffic. After completing its construction in 1997, the bridge was instrumented by the Hong Kong SAR Government Highways Department with a long-term structural health monitoring system comprising about 300 sensors permanently installed on the bridge. As part of this monitoring system, a total of 110 strain gauges have been installed to measure strain at the deck cross-sections and bearings. In this study, a method for real-time structural performance evaluation of the stiffening deck system making use of long-term strain measurement data is proposed and verified using the strain monitoring data from a typical deck cross-section of the Tsing Ma Bridge.

Cleavage and formation of molecular dinitrogen in a single system assisted by molybdenum complexes bearing ferrocenyldiphosphine.

Science.gov (United States)

Miyazaki, Takamasa; Tanaka, Hiromasa; Tanabe, Yoshiaki; Yuki, Masahiro; Nakajima, Kazunari; Yoshizawa, Kazunari; Nishibayashi, Yoshiaki

2014-10-20

The N≡N bond of molecular dinitrogen bridging two molybdenum atoms in the pentamethylcyclopentadienyl molybdenum complexes that bear ferrocenyldiphosphine as an auxiliary ligand is homolytically cleaved under visible light irradiation at room temperature to afford two molar molybdenum nitride complexes. Conversely, the bridging molecular dinitrogen is reformed by the oxidation of the molybdenum nitride complex at room temperature. This result provides a successful example of the cleavage and formation of molecular dinitrogen induced by a pair of two different external stimuli using a single system assisted by molybdenum complexes bearing ferrocenyldiphosphine under ambient conditions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Experimental Estimation of Journal Bearing Stiffness for Damage Detection in Large Hydrogenerators

Directory of Open Access Journals (Sweden)

Geraldo Carvalho Brito

2017-01-01

Full Text Available Based on experimental pieces of evidence collected in a set of twenty healthy large hydrogenerators, this article shows that the operating conditions of the tilting pad journal bearings of these machines may have unpredictable and significant changes. This behavior prevents the theoretical determination of bearing stiffness and damping coefficients with an adequate accuracy and makes damage detection difficult. Considering that dynamic coefficients have similar sensitivity to damage and considering that it is easier to monitor bearing stiffness than bearing damping, this article discusses a method to estimate experimentally the effective stiffness coefficients of hydrogenerators journal bearings, using only the usually monitored vibrations, with damage detection purposes. Validated using vibration signals synthesized by a simplified mathematical model that simulates the dynamic behavior of large hydrogenerators, the method was applied to a journal bearing of a 700 MW hydrogenerator, using two different excitations, the generator rotor unbalance and the vortices formed in the turbine rotor when this machine operates at partial loads. The experimental bearing stiffnesses obtained using both excitations were similar, but they were also much lower than the theoretical predictions. The article briefly discusses the causes of these discrepancies, the method’s uncertainties, and the possible improvements in its application.

Analysis of Static Load Test of a Masonry Arch Bridge

Science.gov (United States)

Shi, Jing-xian; Fang, Tian-tian; Luo, Sheng

2018-03-01

In order to know whether the carrying capacity of the masonry arch bridge built in the 1980s on the shipping channel entering and coming out of the factory of a cement company can meet the current requirements of Level II Load of highway, through the equivalent load distribution of the test vehicle according to the current design specifications, this paper conducted the load test, evaluated the bearing capacity of the in-service stone arch bridge, and made theoretical analysis combined with Midas Civil. The results showed that under the most unfavorable load conditions the measured strain and deflection of the test sections were less than the calculated values, the bridge was in the elastic stage under the design load; the structural strength and stiffness of the bridge had a certain degree of prosperity, and under the in the current conditions of Level II load of highway, the bridge structure was in a safe state.

Experienced iPad-Using Early Childhood Teachers: Practices in the One-to-One iPad Classroom

Science.gov (United States)

Lu, Ya-Huei; Ottenbreit-Leftwich, Anne T.; Ding, Ai-Chu; Glazewski, Krista

2017-01-01

Although many elementary schools have adopted one-to-one programs, we still lack information on how teachers integrate iPads or other tablets into their daily instruction, especially in early childhood settings. The purpose of this case study was to present how four experienced iPad-using early childhood teachers integrated one-to-one iPads into…

Design of bridges against large tectonic deformation

Science.gov (United States)

Anastasopoulos, I.; Gazetas, G.; Drosos, V.; Georgarakos, T.; Kourkoulis, R.

2008-12-01

The engineering community has devoted much effort to understanding the response of soil-structure systems to seismic ground motions, but little attention to the effects of an outcropping fault offset. The 1999 earthquakes of Turkey and Taiwan, offering a variety of case histories of structural damage due to faulting, have (re)fueled the interest on the subject. This paper presents a methodology for design of bridges against tectonic deformation. The problem is decoupled in two analysis steps: the first (at the local level) deals with the response of a single pier and its foundation to fault rupture propagating through the soil, and the superstructure is modeled in a simplified manner; and the second (at the global level) investigates detailed models of the superstructure subjected to the support (differential) displacements of Step 1. A parametric study investigates typical models of viaduct and overpass bridges, founded on piles or caissons. Fixed-head piled foundations are shown to be rather vulnerable to faulting-induced deformation. End-bearing piles in particular are unable to survive bedrock offsets exceeding 10 cm. Floating piles perform better, and if combined with hinged pile-to-cap connections, they could survive much larger offsets. Soil resilience is beneficial in reducing pile distress. Caisson foundations are almost invariably successful. Statically-indeterminate superstructures are quite vulnerable, while statically-determinate are insensitive (allowing differential displacements and rotations without suffering any distress). For large-span cantilever-construction bridges, where a statically determinate system is hardly an option, inserting resilient seismic isolation bearings is advantageous as long as ample seating can prevent the deck from falling off the supports. An actual application of the developed method is presented for a major bridge, demonstrating the feasibility of design against tectonic deformation.

iPad for the Older and Wiser Get Up and Running Safely and Quickly with the Apple iPad

CERN Document Server

McManus, Sean

2011-01-01

Easy-to-follow, friendly advice on using the iPad 2 This heavily illustrated, approachable guide for the anyone over 50 provides a solid resource for learning how to use the iPad in everyday situations. Veteran author and technology expert Sean McManus clearly explains how to use the iPad to send e-mails, listen to music, watch movies, and play games. Detailed coverage walks you step by step through setting up and registering your iPad, connecting to the Internet, syncing your iPad to other devices, and much more. The iPad is an ideal companion for making your life easier, and this friendly gu

iPads og undervisningsdifferentiering

DEFF Research Database (Denmark)

Lorentzen, Rasmus Fink

2013-01-01

Artiklen er blevet til på baggrund af udviklingsprojektet med iPad i Odder Kommune. Den generaliserer på baggrund af en række eksempler herfra og peger på at med iPad'en drejer det sig om at udnytte mulighederne for at lade eleverne arbejde producerende, kollaborativt og fagligt meningsfuldt...

Accelerated Aging of Polymer Composite Bridge Materials

Energy Technology Data Exchange (ETDEWEB)

Carlson, Nancy Margaret; Blackwood, Larry Gene; Torres, Lucinda Laine; Rodriguez, Julio Gallardo; Yoder, Timothy Scott

1999-03-01

Accelerated aging research on samples of composite material and candidate ultraviolet (UV) protective coatings is determining the effects of six environmental factors on material durability. Candidate fastener materials are being evaluated to determine corrosion rates and crevice corrosion effects at load-bearing joints. This work supports field testing of a 30-ft long, 18-ft wide polymer matrix composite (PMC) bridge at the Idaho National Engineering and Environmental Laboratory (INEEL). Durability results and sensor data from tests with live loads provide information required for determining the cost/benefit measures to use in life-cycle planning, determining a maintenance strategy, establishing applicable inspection techniques, and establishing guidelines, standards, and acceptance criteria for PMC bridges for use in the transportation infrastructure.

TPC cathode read-out with C-pads

International Nuclear Information System (INIS)

Janik, R.; Pikna, M.; Sitar, B.; Strmen, P.; Szarka, I.

2009-01-01

A Time Projection Chamber with 'C' like shaped cathode pads was built and tested. It offers a low gas gain operation, a good pulse shape and a lightweight construction. The Pad Response Function (PRF), the cathode to anode pulse height ratios and the pad pulse shapes of the C-pad structure were measured and compared with planar cathode structures in two different wire geometries. The cathode to anode signal ratio was improved from between 0.2 and 0.4 up to 0.7. The PRF was considerably improved, it has a Gaussian shape and is narrower than in the case of the planar pads. The pulse shape from the C-pad read-out is similar to the pulse shape from a detector with a cylindrical shape of electrodes. A method for aluminum pad mass production based on a precise cold forging was developed and tested.

21 CFR 878.4440 - Eye pad.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Eye pad. 878.4440 Section 878.4440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4440 Eye pad. (a) Identification. An eye pad is...

Finite element model updating of a prestressed concrete box girder bridge using subproblem approximation

Science.gov (United States)

Chen, G. W.; Omenzetter, P.

2016-04-01

This paper presents the implementation of an updating procedure for the finite element model (FEM) of a prestressed concrete continuous box-girder highway off-ramp bridge. Ambient vibration testing was conducted to excite the bridge, assisted by linear chirp sweepings induced by two small electrodynamic shakes deployed to enhance the excitation levels, since the bridge was closed to traffic. The data-driven stochastic subspace identification method was executed to recover the modal properties from measurement data. An initial FEM was developed and correlation between the experimental modal results and their analytical counterparts was studied. Modelling of the pier and abutment bearings was carefully adjusted to reflect the real operational conditions of the bridge. The subproblem approximation method was subsequently utilized to automatically update the FEM. For this purpose, the influences of bearing stiffness, and mass density and Young's modulus of materials were examined as uncertain parameters using sensitivity analysis. The updating objective function was defined based on a summation of squared values of relative errors of natural frequencies between the FEM and experimentation. All the identified modes were used as the target responses with the purpose of putting more constrains for the optimization process and decreasing the number of potentially feasible combinations for parameter changes. The updated FEM of the bridge was able to produce sufficient improvements in natural frequencies in most modes of interest, and can serve for a more precise dynamic response prediction or future investigation of the bridge health.

iPad all-in-one for dummies

CERN Document Server

Muir, Nancy C

2012-01-01

Six minibooks in one show you how to power-use the iPad For work, play, and life on the road, the iPad has quickly become indispensable, and the new iPad is packed with even more features and power than ever. In this fun and practical guide, long-time For Dummies author Nancy C. Muir walks you through the latest functions, features, and capabilities of the iPad. Get up to speed on the basics, see how to use your iPad to get more organized and productive, learn to use your iPad for work, and discover all the ways to have fun. This book covers it all, and in full color! Packs six minibooks in on

Study of displacements of a bridge abutment using FEM

Science.gov (United States)

Wymysłowski, Michał; Kurałowicz, Zygmunt

2016-06-01

Steel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented to demonstrate these effects. The structure described is located over the Więceminka river in the town of Kołobrzeg, Poland. It is a single-span road bridge with reinforced concrete slab.

Cosmological applications of Padé approximant

International Nuclear Information System (INIS)

Wei, Hao; Yan, Xiao-Peng; Zhou, Ya-Nan

2014-01-01

As is well known, in mathematics, any function could be approximated by the Padé approximant. The Padé approximant is the best approximation of a function by a rational function of given order. In fact, the Padé approximant often gives better approximation of the function than truncating its Taylor series, and it may still work where the Taylor series does not converge. In the present work, we consider the Padé approximant in two issues. First, we obtain the analytical approximation of the luminosity distance for the flat XCDM model, and find that the relative error is fairly small. Second, we propose several parameterizations for the equation-of-state parameter (EoS) of dark energy based on the Padé approximant. They are well motivated from the mathematical and physical points of view. We confront these EoS parameterizations with the latest observational data, and find that they can work well. In these practices, we show that the Padé approximant could be an useful tool in cosmology, and it deserves further investigation

Cosmological applications of Padé approximant

Science.gov (United States)

Wei, Hao; Yan, Xiao-Peng; Zhou, Ya-Nan

2014-01-01

As is well known, in mathematics, any function could be approximated by the Padé approximant. The Padé approximant is the best approximation of a function by a rational function of given order. In fact, the Padé approximant often gives better approximation of the function than truncating its Taylor series, and it may still work where the Taylor series does not converge. In the present work, we consider the Padé approximant in two issues. First, we obtain the analytical approximation of the luminosity distance for the flat XCDM model, and find that the relative error is fairly small. Second, we propose several parameterizations for the equation-of-state parameter (EoS) of dark energy based on the Padé approximant. They are well motivated from the mathematical and physical points of view. We confront these EoS parameterizations with the latest observational data, and find that they can work well. In these practices, we show that the Padé approximant could be an useful tool in cosmology, and it deserves further investigation.

MuPAD tutorial

CERN Document Server

Creutzig, Christopher

2004-01-01

This book explains the basic use of the software package called MuPAD and gives an insight into the power of the system. MuPAD is a so-called com­ puter algebra system, which is developed mainly by Sciface Software and the MuPAD Research Group of the University of Paderborn in Germany. This introduction addresses mathematicians, engineers, computer scientists, natural scientists and, more generally, all those in need of mathematical com­ putations for their education or their profession. Generally speaking, this book addresses anybody who wants to use the power of a modern computer algebra package. There are two ways to use a computer algebra system. On the one hand, you may use the mathematical knowledge it incorporates by calling system functions interactively. For example, you can compute symbolic integrals or generate and invert matrices by calling appropriate functions. They comprise the system's mathematical intelligence and may implement sophisticated al­ gorithms. Chapters 2 through 15 discuss this...

A bio-based fibre-reinforced plastic pedestrian bridge for Schiphol

NARCIS (Netherlands)

Smits, J.E.P.; Gkaidatzis, R.

2015-01-01

The present paper investigates Bio-based fibre-reinforced plastics, used as a load-bearing element of a bridge. We aim to increase the renewable content and decreasing the embodied energy of FRP. To achieve that, the consisting raw materials of these plastics which are based on non-renewable

Thermal Characterisation of Brake Pads

DEFF Research Database (Denmark)

Ramousse, Séverine; Høj, Jakob Weiland; Sørensen, O. T.

2001-01-01

The chemical-physical decomposition processes that occur in a brake pad heated to 1000degreesC have been studied. This temperature can be reached when a brake pad is applied. Thermogravimetry and differential thermal analysis were used in combination with evolved gas analysis, and image analysis...... using a scanning electron microscope.A brake pad is essentially a mixture of iron, carbon and binder. Combined techniques have been used, because of chemical reaction overlap, to determine how and at what temperature the binder decomposes, the coal and graphite combust and the iron oxidises.This work...

Some studies on structural planning of long-span cable stayed bridge; Choshikan shachokyo no kozo keikaku ni kansuru 2,3 no kosatsu

Energy Technology Data Exchange (ETDEWEB)

Endo, T. [NKK Corp., Tokyo (Japan)

1997-06-20

Feasibility of cabled-stayed bridges with 1000m-grade spans is discussed while re-examining the plan for constructing a Great Tatara Bridge to connect Honshu and Shikoku, Japan, and in this process various tasks and questions are isolated. Some which will be problems in designing the new bridge structure are taken up, including the load-bearing capability of the bridge as a whole, vibration of long cables, resistance to long-period earthquakes, and accuracy management during the construction work. Findings are stated below. A cable-stayed bridge is not significantly different from a suspension bridge and is sufficiently feasible until the span exceeds 1500m. When the span is longer, however, the bridge beam cross section needs be designed very prudently in view of the great axial force and wind load to be imposed on it. Effective for the assurance of load-bearing capability for a long-span cabled-stayed bridge is a structure in which load is elastically confined in the direction of the bridge axis. In connection with vibration damping for very long cables, it is verified that a new dimpled cable suits the purpose of suppressing wind load from increasing without reduction in damping effect. 28 refs., 23 figs., 7 tabs.

iPads in the Classrooms of Schools

DEFF Research Database (Denmark)

Khalid, Md. Saifuddin; Guttesen, Petur Elias Askham

2016-01-01

There is a need for emphasizing on the technological functionalities, pedagogical designs for learning, and barriers to the integration of iPads to inform the resistant teachers, school leaders, parents, and other stakeholders. This paper systematically reviews existing literature on iPads in the......There is a need for emphasizing on the technological functionalities, pedagogical designs for learning, and barriers to the integration of iPads to inform the resistant teachers, school leaders, parents, and other stakeholders. This paper systematically reviews existing literature on i...... categories: 1) functionalities and conveniences in use, 2) iPad motivates, scaffolds learning process, and instills creative problem-solving skills, 3) mobile and multi-contextual, 4) digital content creation and consumption as 21st century skills, 5) barriers to the integration and adoption of iPad, and 6......) scope of future research. There is a dearth of research focusing on the iPad-integrated pedagogical design of subject-specific lessons. This study suggests emphasizing on iPad-integrated pedagogical methods and techniques for subject-specific and app-appropriated learning activity design...

Some remarks on the influence of temperature-variations, non-linearities, repeatability and ageing on modal-analysis for structural health monitoring of real bridges

Directory of Open Access Journals (Sweden)

Maas Stefan

2015-01-01

Full Text Available Structural Health Monitoring (SHM intends to identify damage by changes of characteristics as for instance the modal parameters. The eigenfrequencies, mode-shapes and damping-values are either directly used as damage indicators or the changes of derived parameters are analysed, such as e.g. flexibilities or updated finite element models. One common way is a continuous monitoring under environmental excitation forces, such as wind or traffic, i.e. the so-called output-only modal analysis. Alternatively, a forced measured external excitation in distinct time-intervals may be used for input-output modal analysis. Both methods are limited by the precision or the repeatability under real-life conditions at site. The paper will summarize several field tests of artificially step-by-step damaged bridges prior to their final demolishment and it will show the changes of eigenfrequencies due to induced artificial damage. Additionally, some results of a monitoring campaign of a healthy bridge in Luxembourg are presented. Reinforced concrete shows non-linear behaviour in the sense that modal parameters depend on the excitation force amplitude, i.e. higher forces lead often to lower eigenfrequencies than smaller forces. Furthermore, the temperature of real bridges is neither constant in space nor in time, while for instance the stiffness of asphalt is strongly dependant on it. Finally, ageing as such can also change a bridge’s stiffness and its modal parameters, e.g. because creep and shrinkage of concrete or ageing of elastomeric bearing pads influence their modulus of elasticity. These effects cannot be considered as damage, though they influence the measurement of modal parameters and hinder damage detection.

iPad all-in-one for dummies

CERN Document Server

Muir, Nancy C

2015-01-01

For iPad users who want more information than the basics of the iPad,  iPad All-in-One For Dummies provides the goods! Based on Apple's new iOS software, which includes Siri for iPad, new and improved maps with turn by turn directions, shared photo streams, Facebook integration, Passbook, FaceTime video calls over cellular, new calling features such as instant text reply and callback reminders, improved email with a VIP inbox, iCloud browsing tabs, and much more. The book is organized into the following minibooks: iPad Basics - Covers basic functionality, synching with your computer and getti

iPad 2 The Missing Manual

CERN Document Server

Biersdorfer, JD

2011-01-01

With iOS 5, Apple added more than 200 new features to the iPad 2, but there's still no printed guide to using all its amazing capabilities. That's where this full-color Missing Manual comes in. You'll learn how to stuff your iPad with media, organize your personal life, wirelessly stream content to and from your tablet, stay connected to friends, and much more. The important stuff you need to know: Build your media library. Fill your iPad with music, movies, TV shows, eBooks, eMagazines, photos, and more.Go wireless. Sync content between your computer and iPad-no wires needed.Get online. Con

Effective way to reconstruct arch bridges using concrete walls and transverse strands

Science.gov (United States)

Klusáček, Ladislav; Pěkník, Robin; Nečas, Radim

2017-09-01

There are more than 500 masonry arch bridges in the Czech Road system and about 2500 in the Czech Railway system. Many of them are cracked in the longitudinal (span) direction. The barrel vaults are separated by the cracks into partial masonry arches without load bearing connection in transverse direction. These constructions are about 150 years old and they are also too narrow for the current road system. This paper presents a strengthening method for masonry arch bridges using transverse post-tensioning. This method is very useful not only for strengthening in the transverse direction, but widening of masonry arches can be taken as secondary effect especially in case of road bridges. Several bridges were successfully repaired with the use of this system which seems to be effective and reliable.

iPad application development for dummies

CERN Document Server

Goldstein, l

2012-01-01

The fun and easy guide to creating iPad apps, updated for iOS 5! iPad app development is hot, with more than 140,000 apps available specifically for the device and that number growing every day. The introduction of iOS 5 and iCloud gives developers even more options to create incredible iPad apps. This fast and friendly guide to iPad app development is fully updated for the most recent upgrades and covers everything you need to know, starting with how to download the SDK and become an Apple developer all the way to finishing up your app and submitting it to the App Store. Zeroes in on essentia

Study of displacements of a bridge abutment using FEM

Directory of Open Access Journals (Sweden)

Wymysłowski Michał

2016-06-01

Full Text Available Steel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented to demonstrate these effects. The structure described is located over the Więceminka river in the town of Kołobrzeg, Poland. It is a single-span road bridge with reinforced concrete slab.

Pericruciate fat pad of the knee: anatomy and pericruciate fat pad inflammation: cadaveric and clinical study emphasizing MR imaging

International Nuclear Information System (INIS)

Skaf, Abdalla Youssef; Hernandez Filho, Guinel; Dirim, Berna; Wangwinyuvirat, Mani; Trudell, Debra; Resnick, Donald; Haghigi, Parvitz

2012-01-01

The pericruciate fat pad is located in the intercondylar fossa, intimate with the cruciate ligaments. With MR imaging, signal abnormality of the pericruciate fat pad has been observed in patients with posterior knee pain. The purpose of this study was to describe the anatomy of the pericruciate fat pad in cadaveric specimens and to document the clinical spectrum of pericruciate fat pad inflammation. Twelve cadaveric knees underwent MR imaging with T1 and T2 multiplanar images. Cadaveric sections were then prepared for macroscopic evaluation, with additional histologic analysis performed in four cases. MR images in seventeen patients (ten males, seven females; average age, 31.5 years; age range, 19-57 years) involved in intensive sporting activity and with posterior knee pain were reviewed. MR images in cadaveric specimens showed a fat pad that was located above and between the cruciate ligaments, near their attachment sites in the inner portion of the femoral condyles, within the intercondylar fossa. Fatty tissue covered by a thin layer of synovial membrane was confirmed at histology. Seventeen patients with posterior knee pain and without gross cartilage, meniscal, or ligamentous abnormalities all revealed an increased signal in this fat pad in fluid-sensitive fat-suppressed images, mainly in the sagittal and axial planes. In eight cases, enhancement of this fat pad was demonstrated following intravenous gadolinium administration. The pericruciate fat pad is a structure located in the intercondylar fossa, intimate with both the anterior and posterior cruciate ligaments. Inflammatory changes in this fat pad may be found in patients, especially athletes with posterior knee pain. (orig.)

Pericruciate fat pad of the knee: anatomy and pericruciate fat pad inflammation: cadaveric and clinical study emphasizing MR imaging

Energy Technology Data Exchange (ETDEWEB)

Skaf, Abdalla Youssef [Hospital do Coracao (HCor), Department of Radiology, Sao Paulo, SP (Brazil); Hernandez Filho, Guinel [Santa Casa de Sao Paulo Hospital, Department of Radiology, Sao Paulo, SP (Brazil); Dirim, Berna [Izmir Atatuerk Training and Research Hospital, Department of Radiology, Karsiyaka, izmir (Turkey); Wangwinyuvirat, Mani [Rajavithi Hospital, Department of Radiology, Bangkok (Thailand); Trudell, Debra; Resnick, Donald [University of California, San Diego, Department of Radiology, Veterans Affairs Medical Center, La Jolla, CA (United States); Haghigi, Parvitz [University of California, San Diego, Department of Pathology, Veterans Affairs Medical Center, La Jolla, CA (United States)

2012-12-15

The pericruciate fat pad is located in the intercondylar fossa, intimate with the cruciate ligaments. With MR imaging, signal abnormality of the pericruciate fat pad has been observed in patients with posterior knee pain. The purpose of this study was to describe the anatomy of the pericruciate fat pad in cadaveric specimens and to document the clinical spectrum of pericruciate fat pad inflammation. Twelve cadaveric knees underwent MR imaging with T1 and T2 multiplanar images. Cadaveric sections were then prepared for macroscopic evaluation, with additional histologic analysis performed in four cases. MR images in seventeen patients (ten males, seven females; average age, 31.5 years; age range, 19-57 years) involved in intensive sporting activity and with posterior knee pain were reviewed. MR images in cadaveric specimens showed a fat pad that was located above and between the cruciate ligaments, near their attachment sites in the inner portion of the femoral condyles, within the intercondylar fossa. Fatty tissue covered by a thin layer of synovial membrane was confirmed at histology. Seventeen patients with posterior knee pain and without gross cartilage, meniscal, or ligamentous abnormalities all revealed an increased signal in this fat pad in fluid-sensitive fat-suppressed images, mainly in the sagittal and axial planes. In eight cases, enhancement of this fat pad was demonstrated following intravenous gadolinium administration. The pericruciate fat pad is a structure located in the intercondylar fossa, intimate with both the anterior and posterior cruciate ligaments. Inflammatory changes in this fat pad may be found in patients, especially athletes with posterior knee pain. (orig.)

Isotopic study of the wear of sliding bearings with plastic friction surface

International Nuclear Information System (INIS)

Pandur, J.; Varkonyi, A.

1978-01-01

A new complex device has been elaborated for the investigation of the duration of bearings in the Institute of Isotopes of the Hungarian Academy of Sciences. The simultaneous determination of wear by an isotopic method the coefficient of friction by means of a Wheatstone bridge and the bearing temperature by means of a thermoresistor is described. Dynamic loading and variable revolution per minute are applied to produce a forced wear of the bearings. The isotopically labelled wear products are removed by oil and the collected sample is measured by a scintillation detector. Wear of a steel axle in plastic housing and plastic coated axle in cast iron housing was determined. (V.N.)

Identification Methods and Test Results for Tilting Pad and Fixed Geometry Journal Bearing Dynamic Coefficients – A Review

Directory of Open Access Journals (Sweden)

T.W. Dimond

2009-01-01

Full Text Available Fluid film journal bearings (FFBs are used to support high-speed rotors in turbomachinery which often operate above the rotor first bending critical speed. The FFBs provide both lateral support and dynamic coefficients: stiffness, damping, and mass terms, related to machine vibrations. Detailed numerical values of the bearing dynamic characteristics are necessary for proper design and operation of rotating machinery.

Take control of media on your iPad

CERN Document Server

Carlson, Jeff

2011-01-01

Join media-savvy author Jeff Carlson as he helps you enjoy media on your iPad like never before. Jeff explains basic and advanced ways of adding media to your iPad, and gives you a thorough grounding in Apple's core media apps-iBooks, iPod, Videos, and Photos. He also helps you integrate your iPad with an Apple TV and looks at various ways of using an iPad as a TV remote. You'll also get plenty of suggestions for third-party apps and products, whether you want to read books not available in the iBookstore, stream music from the Internet to your iPad, convert your own DVD library to iPad-frien

Split-cross-bridge resistor for testing for proper fabrication of integrated circuits

Science.gov (United States)

Buehler, M. G. (Inventor)

1985-01-01

An electrical testing structure and method is described whereby a test structure is fabricated on a large scale integrated circuit wafer along with the circuit components and has a van der Pauw cross resistor in conjunction with a bridge resistor and a split bridge resistor, the latter having two channels each a line width wide, corresponding to the line width of the wafer circuit components, and with the two channels separated by a space equal to the line spacing of the wafer circuit components. The testing structure has associated voltage and current contact pads arranged in a two by four array for conveniently passing currents through the test structure and measuring voltages at appropriate points to calculate the sheet resistance, line width, line spacing, and line pitch of the circuit components on the wafer electrically.

21 CFR 890.5740 - Powered heating pad.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Powered heating pad. 890.5740 Section 890.5740...) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5740 Powered heating pad. (a) Identification. A powered heating pad is an electrical device intended for medical purposes...

On-site bridge inspection with partial CT by 3.95Mev X-band linac source

International Nuclear Information System (INIS)

Wu, Wenjing; Zhu, Haito; Jin, Ming

2012-01-01

Since more and more bridges built several decades ago in Japan have become aged and dangerous, the non-destructive evaluation of those bridges is really an urgent problem. CT system with portable 3.95MeV linacs for bridge inspection is considered to work on-site, considering the law of Japanese radiation protection allows using linacs up to 4MeV outside radiation controlled area. The system would confirm the internal steel situation of bridges and analyze structural strain and stress with 3D model built from sectional imaging to evaluate load-bearing performance. The reconstruction process of bridge imaging is based on partial scanned data because bridge shape confines possible scanning angle to smaller than 180deg and a few translations. A small concrete sample with internal steel bars and attachment accessories is scanned in laboratory as preliminary work. (author)

Teach Yourself VISUALLY iPad

CERN Document Server

Watson, Lonzell

2010-01-01

An ideal, visual guide for the image-driven iPad. Whether your interests veer towards movies, games, books, or music—the iPad is the computing device for dazzling graphics, crisp and clear audio, and effortless portability. If ever there existed a device that demanded a reading companion for the visual learner, it's the iPad—and this resource is perfectly suited for the visual audience. Veteran VISUAL author Lonzell Watson walks you through all the features unique to the iPad and shows you how to download books, apps, music, and video content, as well as send photos and e-mails. Plus, you'll d

Numerical and Experimental Stability Investigation of a Flexible Rotor on Two Different Tilting Pad Bearing Configurations

Directory of Open Access Journals (Sweden)

Weimin Wang

2014-01-01

Full Text Available Rotordynamic stability is crucial for high performance centrifugal compressors. In this paper, the weighted instrumental variable (WIV based system identification method for rotating machinery stability is investigated based on a sine sweep forward excitation with an electromagnetic actuator. The traditional multiple input multiple output (MIMO frequency response function (FRF is transformed into a directional frequency response function (dFRF. The rational polynomial method (RPM combined with WIV is developed to identify the rotor’s first forward mode parameters. This new approach is called the COMDYN method. Experimental work using the COMDYN method is carried out under different rotating speeds, oil inlet temperatures, and pressure conditions. Two sets of bearings with preloads 0.1 and 0.3 are investigated. A numerical rotor-bearing model is also built. The numerical results correlate reasonably well with the experimental results. The investigation results indicate that the new method satisfies the desired features of rotating machine stability identification. Furthermore, the system log decrement was improved somewhat with the increase of oil inlet temperature. The increase of oil supply pressure affects the rotor-bearing system stability very slightly. The results of this paper provide new and useful insights for potentially avoiding instability faults in centrifugal compressors.

Generation of monoclonal antibodies against peptidylarginine deiminase 2 (PAD2) and development of a PAD2-specific enzyme-linked immunosorbent assay

DEFF Research Database (Denmark)

Damgaard, Dres; Palarasah, Yaseelan; Skjødt, Karsten

2014-01-01

The enzyme peptidylarginine deiminase 2 (PAD2) has been associated with inflammatory diseases, such as rheumatoid arthritis and neurodegenerative diseases including multiple sclerosis. To investigate the association of various diseases with extracellular PAD2, we raised monoclonal antibodies (m......Abs) against rabbit PAD2 and evaluated their cross-reactivity with human PAD2 by indirect enzyme-linked immunosorbent assay (ELISA), western blotting and immunohistological staining of inflamed synovial tissue. Moreover, we established a sandwich ELISA detecting human PAD2, based on two different monoclonal...... diseases....

EL device pad-printed on a curved surface

International Nuclear Information System (INIS)

Lee, Taik-Min; Hur, Shin; Kim, Jae-Hyun; Choi, Hyun-Cheol

2010-01-01

This paper is unique in that the electroluminescence (EL) display device is fabricated on a curved surface using the pad-printing method. The precision of the pad-printing process is explored to verify whether it can be used for micro patterning. The minimum pattern size and pattern distortion, which is caused by use of the pad, were tested and simulated. The minimal pattern was found to be 35 µm wide and 2.4 µm thick. Pattern distortion when pad-printing on a flat surface, caused by the deformation of the silicon pad, was less than 5 µm. Numerical analysis shows how to estimate pattern distortion when pad-printing on a curved surface. The proposed EL display device consists of five layers, namely a bottom electrode, dielectric layer, phosphor, transparent electrode and a bus electrode. The ink of each layer was reformulated with solvents and the pad-printing conditions were controlled. A PEN film was used first in order to realize the pad-printing process condition of each layer. Finally, the EL display device was printed onto a dish with a radius of curvature of 80 mm. The luminance was 180 cd m −2

21 CFR 880.5270 - Neonatal eye pad.

Science.gov (United States)

2010-04-01

... DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic Devices § 880.5270 Neonatal eye pad. (a) Identification. A neonatal eye pad is an opaque device used to cover... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Neonatal eye pad. 880.5270 Section 880.5270 Food...

Disinfecting the iPad: evaluating effective methods.

Science.gov (United States)

Howell, V; Thoppil, A; Mariyaselvam, M; Jones, R; Young, H; Sharma, S; Blunt, M; Young, P

2014-06-01

Tablet computers are increasingly used in healthcare, but they may carry nosocomial pathogens. There are few data available on how to clean an iPad effectively for use in the clinical setting. We aimed to identify the most effective method of decontaminating the Apple iPad, without causing damage, and establish the duration of any residual effect. Following contamination with a microbial broth (meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococcus (VRE) and Clostridium difficile), we examined efficacy of iPad disinfection in the laboratory using six different disinfectant wipes: Sani-Cloth CHG 2% (chlorhexidine 2%/alcohol 70%), Clorox, Tristel, Trigene, soap and water, and plain cloth. Following cleaning, iPads were recontaminated to examine residual activity. After 480 Sani-Cloth CHG 2% disinfecting episodes, functional and visual analysis of iPads was performed by blinded subjects. With the exception of Clostridium difficile, Sani-Cloth CHG 2% and Clorox wipes were most effective against MRSA and VRE, and they were significantly better than the Apple-recommended plain cloth (P ≤ 0.001). A substantial residual antimicrobial effect was seen for >6h after wiping the iPad with Sani-Cloth CHG 2% despite repeated recontamination and without further disinfection. The functionality or visual appearance of the iPad was not damaged by repeated use of Sani-Cloth CHG 2% wipes. Sani-Cloth CHG 2% wipes effectively disinfect the iPad against MRSA and VRE, with a residual antibacterial effect and without causing damage. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Pad B Liquid Hydrogen Storage Tank

Science.gov (United States)

Hall, Felicia

2007-01-01

Kennedy Space Center is home to two liquid hydrogen storage tanks, one at each launch pad of Launch Complex 39. The liquid hydrogen storage tank at Launch Pad B has a significantly higher boil off rate that the liquid hydrogen storage tank at Launch Pad A. This research looks at various calculations concerning the at Launch Pad B in an attempt to develop a solution to the excess boil off rate. We will look at Perlite levels inside the tank, Boil off rates, conductive heat transfer, and radiant heat transfer through the tank. As a conclusion to the research, we will model the effects of placing an external insulation to the tank in order to reduce the boil off rate and increase the economic efficiency of the liquid hydrogen storage tanks.

Identification of causes and solution strategies for deck cracking in jointless bridges : research report.

Science.gov (United States)

2012-07-01

Bridges have traditionally relied on a system of expansion joints and flexible bearings to accommodate movements due to temperature, creep, and shrinkage loading. Joints and elements in their vicinity experience a high amount of degradation; thus mod...

Monitoring and Evaluation of a Long-Span Raiway Bridge Using SENTINEL-1 Data

Science.gov (United States)

Huang, Q.; Crosetto, M.; Monserrat, O.; Crippa, B.

2017-09-01

This paper is focused on displacement monitoring of a bridge, which is one of the key aspects of its structural health monitoring. A simplified Persistent Scatterer Interferometry (PSI) approach is used to monitor the displacements of the Nanjing Dashengguan Yangtze River High-speed Railway Bridge (China). This bridge is 1272 m long and hosts a total of 6 railway lines. The analysis was based on a set of twenty-nine Sentinel-1A images, acquired from April 2015 to August 2016. A dense set of measurement points were selected on the bridge. The PSI results show a maximum longitudinal displacement of 150 mm, on each side of the bridge. The displacements are strongly correlated with the temperature, showing that they are due to thermal expansion. Using the PSI results, the Coefficient of Thermal Expansion (CTE) of the whole bridge was estimated. The result agrees well with the CTE of the bridge materials. Using a regression model, the PSI-measured displacements were compared with in-situ measurements. The paper proposes a procedure to assess the performance of the movable bearings of the bridge, which is based on the PSI measurements.

A Foil Thrust Bearing Test Rig for Evaluation of High Temperature Performance and Durability

Science.gov (United States)

2008-04-01

composed of similar elements used in journal bearings, but are designed to support a shaft axially. Often, discrete compliant pads are attached... shaft designed to mate with a test thrust runner. The runner is mounted to the shaft with four high strength bolts, and an interference fit ensures...attached to the drive is able to stop the spindle quickly through dynamic braking of the shaft rotational energy. This spindle arrangement has

iPad The Missing Manual

CERN Document Server

Biersdorfer, J

2010-01-01

The iPad 2 is faster, lighter, and more versatile than its predecessor, but there's still no printed guide to using its amazing features. That's where this full-color Missing Manual comes in. Learn how to stream HD video, make video calls, manage your email, surf the Web, listen to music, play games, and maybe even do a little iWork. This is the book that should have been in the box. Build your media library. Fill your iPad with music, movies, TV shows, eBooks, photos, and more.Share with others. Stream music, HD movies, TV shows, and more, to and from your iPad.Create your own media. Use the

Video game induced knuckle pad.

Science.gov (United States)

Rushing, Mary E; Sheehan, Daniel J; Davis, Loretta S

2006-01-01

Controversy and concern surround the video game playing fascination of children. Scientific reports have explored the negative effects of video games on youth, with a growing number recognizing the actual physical implications of this activity. We offer another reason to discourage children's focus on video games: knuckle pads. A 13-year-old black boy presented with an asymptomatic, slightly hyperpigmented plaque over his right second distal interphalangeal joint. A punch biopsy specimen confirmed knuckle pad as the diagnosis, and a traumatic etiology from video game playing was suspected. Knuckle pads can be painful, cosmetically unappealing, and refractory to treatment. They can now be recognized as yet another potential adverse consequence of chronic video game playing.

Brain temperature profiles during epidural cooling with the ChillerPad in a monkey model of traumatic brain injury.

Science.gov (United States)

King, Christopher; Robinson, Timothy; Dixon, C Edward; Rao, Gutti R; Larnard, Donald; Nemoto, C Edwin M

2010-10-01

Therapeutic hypothermia remains a promising treatment for patients with severe traumatic brain injury (TBI). Multiple animal studies have suggested that hypothermia is neuroprotective after TBI, but clinical trials have been inconclusive. Systemic hypothermia, the method used in almost all major clinical trials, is limited by the time to target temperature, the depth of hypothermia, and complications, problems that may be solved by selective brain cooling. We evaluated the effects on brain temperature of a cooling device called the ChillerPad,™ which is applied to the dura in a non-human primate TBI model using controlled cortical impact (CCI). The cortical surface was rapidly cooled to approximately 15°C and maintained at that level for 24 h, followed by rewarming over about 10 h. Brain temperatures fell to 34-35°C at a depth of 15 mm at the cortical gray/white matter interface, and to 28-32°C at 10 mm deep. Intracranial pressure was mildly elevated (8-12 mm Hg) after cooling and rewarming, likely due to TBI. Other physiological variables were unchanged. Cooling was rapidly diminished at points distant from the cooling pad. The ChillerPad may be useful for highly localized cooling of the brain in circumstances in which a craniotomy is clinically indicated. However, because of the delay required by the craniotomy, other methods that are more readily available for inducing hypothermia may be used as a bridge between the time of injury to placement of the ChillerPad.

An experimental investigation of chemical communication in the polar bear

Science.gov (United States)

Owen, Megan A.; Swaisgood, Ronald R.; Slocomb, C.; Amstrup, Steven C.; Durner, George M.; Simac, Kristin S.; Pessier, Allan P.

2015-01-01

The polar bear (Ursus maritimus), with its wide-ranging movements, solitary existence and seasonal reproduction, is expected to favor chemosignaling over other communication modalities. However, the topography of its Arctic sea ice habitat is generally lacking in stationary vertical substrates routinely used for targeted scent marking in other bears. These environmental constraints may have shaped a marking strategy, unique to polar bears, for widely dispersed continuous dissemination of scent via foot pads. To investigate the role of chemical communication, pedal scents were collected from free-ranging polar bears of different sex and reproductive classes captured on spring sea ice in the Beaufort and Chukchi seas, and presented in a controlled fashion to 26 bears in zoos. Results from behavioral bioassays indicated that bears, especially females, were more likely to approach conspecific scent during the spring than the fall. Male flehmen behavior, indicative of chemosignal delivery to the vomeronasal organ, differentiated scent donor by sex and reproductive condition. Histologic examination of pedal skin collected from two females indicated prominent and profuse apocrine glands in association with large compound hair follicles, suggesting that they may produce scents that function as chemosignals. These results suggest that pedal scent, regardless of origin, conveys information to conspecifics that may facilitate social and reproductive behavior, and that chemical communication in this species has been adaptively shaped by environmental constraints of its habitat. However, continuously distributed scent signals necessary for breeding behavior may prove less effective if current and future environmental conditions cause disruption of scent trails due to increased fracturing of sea ice.

Flour pads: devices to improve CHESS fat suppression.

Science.gov (United States)

Moriya, Susumu; Miki, Yukio; Miyati, Tosiaki; Kanagaki, Mitsunori; Yokobayashi, Tsuneo

2014-01-01

We compared the suppression of lingering fat signals in chemical shift selective (CHESS) images by pads filled with flour and pads filled with rice in a phantom and human subjects. First, we prepared a phantom by creating an empty space in a mass of lard and filling the space with air, rice, or flour. Then, we obtained MR images of the phantoms in the center of the magnetic field and at a position 8 cm to the left (off-center) to compare lingering fat signals. MR images of the knee were obtained in 10 healthy volunteers using CHESS after placing a polyurethane sponge pillow, rice pad, or flour pad in the popliteal space under the flexed knee. We visually assessed the number of areas with lingering fat signals and the statistical differences among the groups were assessed using Tukey's test. Similarly to rice, flour clearly decreased lingering fat signals in the phantom study. A similar effect was obtained in the off-center images. In the volunteer study, the mean number of areas with lingering fat signals was 2.5 with a sponge pillow, 0.5 with the rice pad, and 0.3 with the flour pad. Those numbers were significantly different using flour pad and rice pad compared with sponge pillow (P CHESS images.

Numerical investigation into thermal load responses of steel railway bridge

Science.gov (United States)

Saravana Raja Mohan, K.; Sreemathy, J. R.; Saravanan, U.

2017-07-01

Bridge design requires consideration of the effects produced by temperature variations and the resultant thermal gradients in the structure. Temperature fluctuation leads to expansion and contraction of bridges and these movements are taken care by providing expansion joints and bearings. Free movements of a member can be restrained by imposing certain boundary condition but at the same time considerable allowances should be made for the stresses resulting from this restrained condition since the additional deformations and stresses produced may affect the ultimate and serviceability limit states of the structure. If the reaction force generated by the restraints is very large, then its omission can lead to unsafe design. The principal objective of this research is to study the effects of temperature variation on stresses and deflection in a steel railway bridge. A numerical model, based on finite element analysis is presented for evaluating the thermal performance of the bridge. The selected bridge is analyzed and the temperature field distribution and the corresponding thermal stresses and strains are calculated using the finite element software ABAQUS. A thorough understanding of the thermal load responses of a structure will result in safer and dependable design practices.

Evaluating the performance of skewed prestressed concrete bridge after strengthening

Science.gov (United States)

Naser, Ali Fadhil; Zonglin, Wang

2013-06-01

The objectives of this paper are to explain the application of repairing and strengthening methods on the damaged members of the bridge structure, to analyze the static and dynamic structural response under static and dynamic loads after strengthening, and to evaluate the structural performance after application of strengthening method. The repairing and strengthening methods which are used in this study include treatment of the cracks, thickening the web of box girder along the bridge length and adding internal pre-stressing tendons in the thickening web, and construct reinforced concrete cross beams (diaphragms) between two box girders. The results of theoretical analysis of static and dynamic structural responses after strengthening show that the tensile stresses are decreased and become less than the allowable limit values in the codes. The values of vertical deflection are decreased after strengthening. The values of natural frequencies after strengthening are increased, indicating that the strengthening method is effective to reduce the vibration of the bridge structure. Therefore, the strengthening methods are effective to improve the bearing capacity and elastic working state of the bridge structure and to increase the service life of the bridge structure.

Use of structured surfaces for friction and wear control on bearing surfaces

International Nuclear Information System (INIS)

Wang, Ling

2014-01-01

Surface texturing with purposely made regular micropatterns on flat or curved surfaces, as opposed to random roughness inherited from machining processes, has attracted significant attention in recent years. At the 2013 World Tribology Congress in Turin alone there were over 40 presentations related to surface texturing for tribological applications, from magnetic hard discs and hydrodynamic bearings to artificial joints. Although surface texturing has been reported being successfully applied in industrial applications such as seals, pistons, and thrust pad bearings, the demand for robust design is still high. Etsion has recently reviewed the modeling research mainly conducted by his group Etsion I (2013 Friction 1 195–209). This paper aims to review the state-of-the-art development of surface texturing made by a wider range of researchers. (topical review)

16 CFR 1632.5 - Mattress pad test procedure.

Science.gov (United States)

2010-01-01

... 1632.5 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS... substrate. (b) Flame resistant mattress pads. The following additional requirements shall be applicable to mattress pads which contain a chemical fire retardant. (1) These mattress pads shall be tested in...

Non-Uniform Laser Surface Texturing of an Un-Tapered Square Pad for Tribological Applications

Directory of Open Access Journals (Sweden)

Antonio Ancona

2017-10-01

Full Text Available Femtosecond laser surface micro-texturing has emerged as a promising technology to enhance the tribological properties of different kinds of electromechanical devices. In this research paper, we have exploited the intrinsic flexibility and micrometric accuracy of femtosecond laser ablation to realize complex micro-structural modifications on the surface of a laboratory prototype of a steel thrust bearing (un-tapered pad. The Bruggeman Texture Hydrodynamics theory (BTH is employed for the design of the anisotropic and non-uniform texture maximizing the thrust load of the pad prototype. The preliminary experimental results, reported in this work, show that the non-uniform micro-texture largely affects the friction characteristics of the contact. In particular, in agreement with the BTH predictions, the tribo-system shows friction properties that are strongly sensitive to the direction of the sliding speed, as a consequence of the micro-fluid dynamics which are designed to occur only in a specific sliding direction. We suggest that the joint action of virtual prototyping (BTH lubrication theory and ultrafast laser micro-prototyping can lead to unconventional and impressive results in terms of enhanced or tailored contact mechanics properties of the generic lubricated tribopair.

Stopping the wave of PAD.

Science.gov (United States)

Brazziel, Tracy; Cox, Lindsie; Drury, Christa; Guerra, Maria

2011-11-01

Peripheral arterial disease (PAD) has a substantial impact on individual quality of life and is a significant financial burden to society. It is underdiagnosed, and therefore, undertreated. Early detection and treatment is essential to prevent increases in morbidity and mortality. The purpose of this article is to review evidence-based articles regarding prevalence, screening, diagnosis, and management of PAD. Copyright © 2011 Lippincott Williams & Wilkins.

TagPad

DEFF Research Database (Denmark)

Bornoe, Nis; Barkhuus, Louise

2013-01-01

The area of cyberinfrastructures has looked extensively at research within the natural sciences, however, the social sciences have been largely overlooked in terms of novel data collection and analysis systems. We developed a probe tool, TagPad, to look at the process for social science data...

Taking Your iPad 2 to the Max

CERN Document Server

Sadun, Erica; Sande, Steve

2011-01-01

iPad 2: It looks different. It acts different. It connects to the world, yet it is as personal as a well-worn book. And now it has two cameras!. Taking Your iPad 2 to the Max is written so that anyone can quickly get up to speed on Apple's latest hit. As bloggers at The Unofficial Apple Weblog (TUAW.com), the authors have the happy privilege of working with Apple products every day, and they'll guide you through all of the perks of being an iPad 2 owner. This book takes you from selecting and buying an iPad, to connecting it to the Internet, to using the incredible power of the iPad and all it

Fatigue of cable anchorage of large cable stayed bridge; Daikibo shachokyo cable teichaku kozo no hiro

Energy Technology Data Exchange (ETDEWEB)

Endo, T.; Matsumoto, T. [Honshu-Shikoku Bridge Authority, Tokyo (Japan); Tsukahara, H. [Yokogawa Bridge Corp., Tokyo (Japan); Miki, C. [Tokyo Institute of Technology, Tokyo (Japan)

1995-10-21

Design considerations such as design schemes, the assemblage and welding of steel plates, and safety for fatigue of welded connections have to be taken for the cable anchorages of the steel cable stayed bridges. In this study, two full scale models, which have different shape of box anchorages welded to the web of the main girder, were made to investigate fatigue characteristics as well as assemblage of plate and gelding details. Finite element analyses for both test models and actual bridges here carried out to compare stress distribution. It was confirmed that the assemblage and welding of both types of box anchorage were attainable kith required quality and accuracy. According to the fatigue test, fatigue cracks originated from the weldings of the bearing plate to which the load from cable socket applied directly were caused by out-of-plane bending of the bearing plate. It was proved that the slight modifications of the details around the bearing plate resulted in sufficient fatigue strength in both types of anchorage. 1 ref., 23 figs., 2 tabs.

ACNE VULGARIS. EVALUATION OF A MEDICATED CLEANSING PAD.

Science.gov (United States)

ROTH, H L

1964-03-01

Using the technique of simultaneous, symmetrical paired comparisons, a medicated cleansing pad that can be easily used at work or at school as an adjunctive in the treatment of acne vulgaris was evaluated.The experimental pads were significantly beneficial in reducing skin oiliness and in clinical improvement of the acne. Response to standard acne therapy was faster when the pads were used adjunctively, although the significant results seen initially tended to even out as therapy continued. Use of the medicated pads produced no untoward side effects and were well accepted by patients.

ACNE VULGARIS—Evaluation of a Medicated Cleansing Pad

Science.gov (United States)

Roth, Harry L.

1964-01-01

Using the technique of simultaneous, symmetrical paired comparisons, a medicated cleansing pad that can be easily used at work or at school as an adjunctive in the treatment of acne vulgaris was evaluated. The experimental pads were significantly beneficial in reducing skin oiliness and in clinical improvement of the acne. Response to standard acne therapy was faster when the pads were used adjunctively, although the significant results seen initially tended to even out as therapy continued. Use of the medicated pads produced no untoward side effects and were well accepted by patients. PMID:14131397

Ouders positief over iPad in het onderwijs

NARCIS (Netherlands)

Klaas Jan Huizing; Kirsten Andringa; Jildou Braaksma

2014-01-01

In 2012 is de iPad geïmplementeerd in het voorgezet middelbare onderwijs van Piter Jelles de Dyk in Leeuwarden. Sowijs volgde de implementatie van de iPad. In dit whitepaper wordt beschreven hoe ouders van leerlingen het iPad-gebruik op school ervaren. Welke voor- of nadelen zien zij in het

Comparison of postural sway depending on balance pad type.

Science.gov (United States)

Lee, DongGeon; Kim, HaNa; An, HyunJi; Jang, JiEun; Hong, SoungKyun; Jung, SunHye; Lee, Kyeongbong; Choi, Myong-Ryol; Lee, Kyung-Hee; Lee, GyuChang

2018-02-01

[Purpose] The purpose of the present study was to compare the postural sway of healthy adults standing on different types of balance pads. [Subjects and Methods] Nine healthy adults participated in this study. Postural body sway was measured while participants were standing on four different types of balance pads: Balance-pad Elite (BE), Aero-Step XL (AS), Dynair Ballkissen Senso (DBS), and Dynair Ballkissen XXL Meditation and Yoga (DBMY). A Wii Balance Board interfaced with Balancia software was used to measure postural body sway. [Results] In the sway velocity, sway path length, and sway area, no significant differences were found between baseline conditions (participants were standing on the floor with no balance pad) and the use of the BE or AS. However, significant increases in all parameters were found comparing baseline conditions to the use of either Dynair balance pad. Furthermore, the use of either Dynair balance pad significantly increased postural sway compared to both the BE and the AS. [Conclusion] These findings suggest that the DBS and DBMY balance pads may serve as superior tools for providing unstable condition for balance training than the BE and the AS balance pads.

POWER SPECTRUM DENSITY (PSD ANALYSIS OF AUTOMOTIVE PEDAL-PAD

Directory of Open Access Journals (Sweden)

AHMED RITHAUDDEEN YUSOFF

2016-04-01

Full Text Available Vibration at the pedal-pad may contribute to discomfort of foot plantar fascia during driving. This is due to transmission of vibration to the mount, chassis, pedal, and then to the foot plantar fascia. This experimental study is conducted to determine the estimation of peak value using the power spectral density of the vertical vibration input at the foot. The power spectral density value is calculated based on the frequency range between 13 Hz to 18 Hz. This experiment was conducted using 12 subjects testing on three size of pedal-pads; small, medium and large. The result shows that peak value occurs at resonance frequency of 15 Hz. The PSD values at that resonance frequency are 0.251 (m/s2 2/Hz for small pedal-pad, followed by the medium pedal-pad is at 0.387 (m/s2 2/Hz and lastly for the large pedal-pad is at 0.483 (m/s22/Hz. The resultsindicate that during driving, the foot vibration when interact with the large pedal-pad contributed higher stimulus compared with the small and medium pedal-pad. The pedal-pad size plays an important role in the pedal element designs in terms of vibration-transfer from pedal-pads on the feet, particularly to provide comfort to the driver while driving.

Disassembly of an arch bridge deformed due to landslide activity and the replacement of a new bridge in the same site. Jisuberi ni yori henkei shita arch bashi no kaitai to shinbashi no kakekae

Energy Technology Data Exchange (ETDEWEB)

Sano, S; Morimoto, C; Tomoda, T; Mizukawa, Y; Onushi, M; Ito, T [Kawasaki Heavy Industries, Ltd., Tokyo (Japan)

1991-10-20

This report describes the replacement process of an arch bridge deformed due to landslide activity, selection and contents of the disassembly method, and configuration of the new bridge and its design method. The Ryugu Bridge had been damaged by landslides over an extended period. It was a deck arch bridge having originally a span of 74 meters, but it had shortened by 424 mm due to landslide activity during 14 years since its completion. Then it was decided to be replaced by a new bridge having an adjustable structure to support the movement of its abutments. As disassembly of the deformed arch bridge could be dangerous, the best methodology was studied, and the disassembly was carried out by the cable method. The new bridge had box-girder parts in both side of the main truss, so as to be adjustable to the change of the span length, and the bridge was designed for a working life of 50 years if the bearing supports and expansion joints were reset every 10 years. Concerning the connecting parts between the box-girder and the main truss, appropriateness of the sectional configuration was verified by FEM analysis. 9 refs., 18 figs., 2 tab.

iPad For Seniors For Dummies

CERN Document Server

Muir, Nancy C

2010-01-01

The full-color guide to the exciting new iPad, written specifically with the needs of seniors in mind!. The iPad is the perfect device for the senior market, combining the Web, e-mail, photos, video, and book reading into an intuitive, portable device. Written by veteran Dummies author Nancy Muir, this fun and friendly guide shows you how to use the many features and capabilities of the iPad to make life easier! You'll learn how to use the multitouch screen to zoom in and out on Web pages and choose a font and size that makes reading comfortable so that you can get directions, plan vacations,

Diagnosis of heel pad injuries

DEFF Research Database (Denmark)

Matteoli, Sara

The biomechanics of in vivo heel pads has been investigated for more than 30 years, but unfortunately numerical results from the many individual investigators cannot be compared due to the different methodologies used, and the sometimes modest number of subjects investigated. The overall aim...... of the present thesis is to obtain a thorough understanding of the mechanical properties of in vivo human heel pad by studying the anatomical and physiological structure of healthy and diseased tissue, and to develop quantitative methods for diagnosing injuries. A compression device was built in order to record...... load-displacement curves from in vivo heel pads. To ensure applicability also for pathological feet, the device uses force levels lower than those needed to reproduce the physiological conditions of walking. One hundred twenty seven healthy volunteers were enrolled for compression tests and ultrasound...

Cascading Tesla Oscillating Flow Diode for Stirling Engine Gas Bearings

Science.gov (United States)

Dyson, Rodger

2012-01-01

Replacing the mechanical check-valve in a Stirling engine with a micromachined, non-moving-part flow diode eliminates moving parts and reduces the risk of microparticle clogging. At very small scales, helium gas has sufficient mass momentum that it can act as a flow controller in a similar way as a transistor can redirect electrical signals with a smaller bias signal. The innovation here forces helium gas to flow in predominantly one direction by offering a clear, straight-path microchannel in one direction of flow, but then through a sophisticated geometry, the reversed flow is forced through a tortuous path. This redirection is achieved by using microfluid channel flow to force the much larger main flow into this tortuous path. While microdiodes have been developed in the past, this innovation cascades Tesla diodes to create a much higher pressure in the gas bearing supply plenum. In addition, the special shape of the leaves captures loose particles that would otherwise clog the microchannel of the gas bearing pads.

iPads in Higher Education--Hype and Hope

Science.gov (United States)

Nguyen, Lemai; Barton, Siew Mee; Nguyen, Linh Thuy

2015-01-01

This paper systematically reviews current research on using iPads in the higher education sector. Since the release of iPads by Apple in 2010, this new technology has been quickly adopted everywhere, especially by the younger generation and professionals. We were motivated to find out how iPads have been adopted for use in the higher education…

Seismic Response Analysis of Continuous Multispan Bridges with Partial Isolation

Directory of Open Access Journals (Sweden)

E. Tubaldi

2015-01-01

Full Text Available Partially isolated bridges are a particular class of bridges in which isolation bearings are placed only between the piers top and the deck whereas seismic stoppers restrain the transverse motion of the deck at the abutments. This paper proposes an analytical formulation for the seismic analysis of these bridges, modelled as beams with intermediate viscoelastic restraints whose properties describe the pier-isolator behaviour. Different techniques are developed for solving the seismic problem. The first technique employs the complex mode superposition method and provides an exact benchmark solution to the problem at hand. The two other simplified techniques are based on an approximation of the displacement field and are useful for preliminary assessment and design purposes. A realistic bridge is considered as case study and its seismic response under a set of ground motion records is analyzed. First, the complex mode superposition method is applied to study the characteristic features of the dynamic and seismic response of the system. A parametric analysis is carried out to evaluate the influence of support stiffness and damping on the seismic performance. Then, a comparison is made between the exact solution and the approximate solutions in order to evaluate the accuracy and suitability of the simplified analysis techniques for evaluating the seismic response of partially isolated bridges.

Er iPad digital udeskole?

DEFF Research Database (Denmark)

Schilhab, Theresa

2014-01-01

Hvor ’konkret’ skal en oplevelse være, for at intuitionen om, at det selvoplevede styrker læringen, holder? Er brug af tablets (e.g. iPads) et ligebyrdigt alternativ til den konkrete oplevelse?......Hvor ’konkret’ skal en oplevelse være, for at intuitionen om, at det selvoplevede styrker læringen, holder? Er brug af tablets (e.g. iPads) et ligebyrdigt alternativ til den konkrete oplevelse?...

Binocular iPad treatment for amblyopia in preschool children.

Science.gov (United States)

Birch, Eileen E; Li, Simone L; Jost, Reed M; Morale, Sarah E; De La Cruz, Angie; Stager, David; Dao, Lori; Stager, David R

2015-02-01

Recent experimental evidence supports a role for binocular visual experience in the treatment of amblyopia. The purpose of this study was to determine whether repeated binocular visual experience with dichoptic iPad games could effectively treat amblyopia in preschool children. A total of 50 consecutive amblyopic preschool children 3-6.9 years of age were assigned to play sham iPad games (first 5 children) or binocular iPad games (n = 45) for at least 4 hours per week for 4 weeks. Thirty (67%) children in the binocular iPad group and 4 (80%) in the sham iPad group were also treated with patching at a different time of day. Visual acuity and stereoacuity were assessed at baseline, at 4 weeks, and at 3 months after the cessation of game play. The sham iPad group had no significant improvement in visual acuity (t4 = 0.34, P = 0.75). In the binocular iPad group, mean visual acuity (plus or minus standard error) improved from 0.43 ± 0.03 at baseline to 0.34 ± 0.03 logMAR at 4 weeks (n = 45; paired t44 = 4.93; P iPad games for ≥8 hours (≥50% compliance) had significantly more visual acuity improvement than children who played 0-4 hours (t43 = 4.21, P = 0.0001). Repeated binocular experience, provided by dichoptic iPad game play, was more effective than sham iPad game play as a treatment for amblyopia in preschool children. Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

Damage of the Unit 1 reactor building overhead bridge crane at Onagawa Nuclear Power Station caused by the Great East Japan Earthquake and its repair works

International Nuclear Information System (INIS)

Sugamata, Norihiko

2014-01-01

The driving shaft bearings of the Unit 1 overhead bridge crane were damaged by the Great East Japan Earthquake at Onagawa Nuclear Power Station. The situation, investigation and repair works of the bearing failure are introduced in this paper. (author)

Using iPads to Your Advantage

Science.gov (United States)

Zakrzewski, Jennifer L.

2016-01-01

In this article, middle school mathematics teacher Jennifer Zakrzewski describes how she successfully incorporated iPads and Apple TV (for projection of iPad screens) into her classroom while having her students solve a problem about mangoes. As Zakrzewski began a unit on multiplying and dividing fractions, she chose to start with the Mangoes…

STRENGTHENING OF A REINFORCED CONCRETE BRIDGE WITH PRESTRESSED STEEL WIRE ROPES

Directory of Open Access Journals (Sweden)

Kexin Zhang

2017-10-01

Full Text Available This paper describes prestressed steel wire ropes as a way to strengthen a 20-year-old RC T-beam bridge. High strength, low relaxation steel wire ropes with minor radius, high tensile strain and good corrosion resistance were used in this reinforcement. The construction process for strengthening with prestressed steel wire ropes—including wire rope measuring, extruding anchor heads making, anchorage installing, tensioning steel wire ropes and pouring mortar was described. Ultimate bearing capacity of the bridge after strengthening was discussed based on the concrete structure theory. The flexural strength of RC T-beam bridges strengthened with prestressed steel wire ropes was governed by the failure of concrete crushing. To investigate effectiveness of the strengthening method, fielding-load tests were carried out before and after strengthening. The results of concrete strain and deflection show that the flexural strength and stiffness of the strengthened beam are improved. The crack width measurement also indicates that this technique could increase the durability of the bridge. Thus, this strengthened way with prestressed steel wire rope is feasible and effective.

Application study on the first cable-stayed bridge with CFRP cables in China

Directory of Open Access Journals (Sweden)

Kuihua Mei

2015-08-01

Full Text Available In order to push forward the development of CFRP cable-stayed bridge and accumulate experiences, the study on the application of the first cable-stayed bridge with CFRP cables in China was carried out. The design essentials of main components of the bridge were introduced and its integral performances, including static properties, dynamic properties and seismic response were analyzed using finite element method. A new bond-type anchorage was developed and the processes of fabricating and installing CFRP cables were elaborated. Based on the results of construction simulation, a tension scheme for bridge was propound. During constructing, the stresses and displacement of girder and pylon, as well as the forces and stresses of cables, were tested. The results indicate that all sections of the bridge could meet the requirements of the ultimate bearing capacity and normal service; the performance of the anchorage is good and the stresses in each cable system are similar; the tested values accord well with the calculated values. Further, creep deformation of the resin in anchorages under service load is not obvious. All these results demonstrate that the first application of CFRP cables in the cable-stayed bridge in China is successful.

Resident iPad use: has it really changed the game?

Science.gov (United States)

Berkowitz, Seth J; Kung, Justin W; Eisenberg, Ronald L; Donohoe, Kevin; Tsai, Leo L; Slanetz, Priscilla J

2014-02-01

The purpose of this study was to assess residents' usage patterns and opinions of the iPad as a tool for radiology education and clinical practice at an academic medical center. All 38 radiology residents in our radiology program (postgraduate years 2 to 5) were provided with iPad 2 tablets and subscriptions to e-Anatomy and STATdx. After 6 months of device use, residents were surveyed to assess their opinions regarding the technology as a tool for education and clinical practice. A total of 36 residents (95%) completed the survey. Eighty-six percent reported daily iPad use. Radiology-specific applications, particularly e-Anatomy, were used weekly or daily by 88% of respondents. Most preferred to read journal articles on the iPad (70%), but the number of respondents preferring to read textbooks on the iPad (48.5%) compared with the traditional bound form (48.5%) was evenly divided. Residents were also divided on the clinical utility of the iPad. Most had not used the iPad to view radiologic examinations (75%). Fewer than half (47%) used their iPads during readout. Finally, only 12% had used the iPad to edit dictated reports. The iPad has generated excitement within the radiology community, particularly among resident educators, who are increasingly recognizing the unique needs of "millennial learners." This study showed that the majority of residents at the authors' institution have incorporated the iPad as an educational tool and use it as a learning aid. Incorporation of the iPad into clinical workflow has been less pronounced. Copyright © 2014 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Learning Chinese Idioms through iPads

Science.gov (United States)

Yang, Chunsheng; Xie, Ying

2013-01-01

This paper reports on an action research study using iPads during the teaching of Chinese idioms to heritage learners. A class of 12 second-year Chinese learners were engaged in a self-generated learning process focused on learning abstract and concrete idioms using iPads. Students' short-term and long-term learning was measured; feedback from a…

Development of Asbestos - Free Brake Pad Using Bagasse

Directory of Open Access Journals (Sweden)

V. S. Aigbodion

2010-03-01

Full Text Available Development of asbestos-free brake pad using bagasse was investigated with a view to replace the use of asbestos whose dust is carcinogenic. The bagasse were sieve into sieve grades of 100, 150, 250, 350 and 710µm. the sieve bagasse was used in production of brake pad in ratio of 70%bagasse-30%resin using compression moulding. The properties examined are microstructure analysis, hardness, compressive strength, density, flame resistance, water and oil absorption. The microstructure reveals uniform distribution of resin in the bagasse. The results obtained showed that the finer the sieve size the better the properties. The results obtained in this work were compared with that of commercial brake pad (asbestos based and optimum formulation laboratory brake pad Palm Kernel Shell based (PKS, the results are in close agreement. Hence bagasse can be used in production of asbestos-free brake pad.

Development testing of high temperature bearings for SP-100 control drive assemblies

Science.gov (United States)

Dalcher, Alfred W.; Kjaer-Olsen, Christian G.; Martinez, Carlos; Ogawa, Stanley Y.; Springer, Dwight R.; Yaspo, Robert

1992-01-01

Initial phases of two distinct SP-100 control drive assembly bearing test programs were successfully completed at elevated temperature in vacuum. The first was for the reflector drive line spherical self-aligning bearings. Each bearing consisted of a carbon-graphite ball mounted on an aluminum oxide-coated Ta-10%W shaft, captured by an aluminum oxide-coated Ta-10%W socket. One set of these bearings was exposed to temperatures up to 1180K (1665°F) at 1.33×10-6 Pa (1×10-8 torr) and subjected to 38000 cycles of motion. Friction coefficients were found to be between 0.11 and 0.25 over the full range of operation. Overall performance of the bearings was excellent, with only slight wear observed. The second test program was for the safety rod slider bearing. Zirconium carbide coated Nb-1%Zr bearings pads were stroked inside a molybdenum tube at temperatures up to 1422 K (2100°F) at ˜1.33×10-6 Pa with a normal load of 1.02 Kg between each sliding surface. Coefficients of sliding friction were found to increase from 0.90 at 293 K to 1.20 at 1422 K prior to high temperature dwells. Results were consistent over the range of stroke velocities; 5.1 to 51 mm (0.2 to 2.0 inches) per second. Following dwells of 92, 72, and 110 hours at 1422 K, static friction coefficients as high as 5.4 were observed prior to initiation of sliding, after which sliding friction coefficients of ˜1.6 were seen. Breakaway forces were well within the actuator design limits.

Medical student use of the iPad in the clerkship curriculum.

Science.gov (United States)

Youm, Julie; Wiechmann, Warren

2015-12-01

There is little precedence for the implementation of a medical school iPad programme in a clinical setting. This study analysed students' use of iPad apps and perceptions of the iPad as a clinical tool in a clinical third-year medical school curriculum. All third-year medical students (n = 103) were provided iPads for use during their regular clinical rotations. Students received an orientation that included an introduction to the recommended apps selected for the study. A pre-survey (82.5% response rate) and post-survey (47.6% response rate) were administered to determine students' use of specific iPad programs, activities performed on the iPad and their perceptions. Students reported technology proficiency with the iPad and positive perceptions about its use in a clinical setting. They reported using a few key apps out of the many specialty-specific apps recommended to them. Students found efficiency through their ability to study during downtime, and through quick access to information and mobile access to electronic medical records, amongst the greatest benefits of having an iPad during their rotations. Improving Wi-Fi infrastructure and offering timely iPad orientations could decrease challenges to students' clinical iPad apps use. This study analysed students' use of iPad apps and perceptions of the iPad as a clinical too. © 2015 John Wiley & Sons Ltd.

Human-simulated intelligent control of train braking response of bridge with MRB

Science.gov (United States)

Li, Rui; Zhou, Hongli; Wu, Yueyuan; Wang, Xiaojie

2016-04-01

The urgent train braking could bring structural response menace to the bridge under passive control. Based on the analysis of breaking dynamics of a train-bridge vibration system, a magnetorheological elastomeric bearing (MRB) whose mechanical parameters are adjustable is designed, tested and modeled. A finite element method (FEM) is carried out to model and optimize a full scale vibration isolation system for railway bridge based on MRB. According to the model above, we also consider the effect of different braking stop positions on the vibration isolation system and classify the bridge longitudinal vibration characteristics into several cases. Because the train-bridge vibration isolation system has multiple vibration states and strongly coupling with nonlinear characteristics, a human-simulated intelligent control (HSIC) algorithm for isolating the bridge vibration under the impact of train braking is proposed, in which the peak shear force of pier top, the displacement of beam and the acceleration of beam are chosen as control goals. The simulation of longitudinal vibration control system under the condition of train braking is achieved by MATLAB. The results indicate that different braking stop positions significantly affect the vibration isolation system and the structural response is the most drastic when the train stops at the third cross-span. With the proposed HSIC smart isolation system, the displacement of bridge beam and peak shear force of pier top is reduced by 53.8% and 34.4%, respectively. Moreover, the acceleration of bridge beam is effectively controlled within limited range.

Elastic modulus of tree frog adhesive toe pads.

Science.gov (United States)

Barnes, W Jon P; Goodwyn, Pablo J Perez; Nokhbatolfoghahai, Mohsen; Gorb, Stanislav N

2011-10-01

Previous work using an atomic force microscope in nanoindenter mode indicated that the outer, 10- to 15-μm thick, keratinised layer of tree frog toe pads has a modulus of elasticity equivalent to silicone rubber (5-15 MPa) (Scholz et al. 2009), but gave no information on the physical properties of deeper structures. In this study, micro-indentation is used to measure the stiffness of whole toe pads of the tree frog, Litoria caerulea. We show here that tree frog toe pads are amongst the softest of biological structures (effective elastic modulus 4-25 kPa), and that they exhibit a gradient of stiffness, being stiffest on the outside. This stiffness gradient results from the presence of a dense network of capillaries lying beneath the pad epidermis, which probably has a shock absorbing function. Additionally, we compare the physical properties (elastic modulus, work of adhesion, pull-off force) of the toe pads of immature and adult frogs.

IT Does Not Love iPads

Science.gov (United States)

Fredette, Michelle

2013-01-01

On many campuses, iPads have taken over the hearts and minds of everyone. Everyone, that is, except the IT department. These sexy tablets might be the apple of faculty and students' eyes, but for IT directors and their staffs, working with iPads in an enterprise network environment is not the stuff of a love affair. To state the problem…

Enter the iPad (or Not?)

Science.gov (United States)

Waters, John K.

2010-01-01

Few computing devices have sparked the burning gizmo lust ignited by the iPad. Apple's latest entry into the tablet PC market didn't generate much heat when it was first unveiled in January, but by April 3, the day of the official release, feverish customers were mobbing Apple stores. The company claims to have sold 300,000 iPads by midnight on…

iPad use in Iowa Research Network family physician offices.

Science.gov (United States)

Daly, Jeanette M; Xu, Yinghui; Levy, Barcey T

2015-04-01

Through a cancer research infrastructure building grant, iPads were given to health care providers in family physician offices. The purpose of this study was to determine the use and application of iPads in the Iowa Research Network. A Qualtrics survey was sent to 81 iPad recipients after institutional review board approval. Fifty-nine percent responded and 85% reported they have used the iPad. The main reason for use of the iPad was browsing the World Wide Web for health care information. Open-ended comments supported use of the iPad for photographic documentation of wound and other skin lesions for insertion into the medical record and it helped improve clinic flow by making it easier to put orders in the system through the iPad. Tablet uses are variable in physician offices with provider's gathering health care information from the Internet and securing education material for patients as the frequent usages. © The Author(s) 2014.

Tests of MVD prototype pad detector with a β- source

International Nuclear Information System (INIS)

Yeol Kim, Sang; Gook Kim, Young; Su Ryu, Sang; Hwan Kang, Ju; Simon-Gillo, Jehanne; Sullivan, John P.; Heck, Hubert W. van; Xu Guanghua

1999-01-01

The MVD group has been testing two versions of silicon pad detectors. One design uses a single metal layer for readout trace routing. The second type uses two layers of metal, allowing for greatly simplified signal routing. However, because the readout traces for the pads pass over the other pads in the same column (separated by an oxide layer), the double-metal design introduces crosstalk into the system. A simple test stand using a 90 Sr β - source with scintillator triggers was made to estimate the crosstalk. The crosstalk between pads in the same column of the pad detector was 1.6-3.1%. The values measured between pads in different columns were very close to zero. The measured crosstalk was below our maximum allowed value of 7.8%

Stretchable touch-sensing skin over padding for co-robots

International Nuclear Information System (INIS)

Chen, Ying; Yu, Miao; Bruck, Hugh A; Smela, Elisabeth

2016-01-01

For robots that work collaboratively with people, often referred to as ‘co-robots’, it would be beneficial for them to be soft or padded and to have a touch-sensing ‘skin’ to enable tactile environmental awareness. However, a sensing skin over a padding material that undergoes large deformations requires ‘stretchable’ materials, which may possess time-dependent or viscoelastic mechanical responses. In this work the roles that a padding layer plays when placed under a stretchable sensing layer was investigated. A strain-sensing skin was formed by coating a thin film of compliant piezoresistive sensing paint, consisting of exfoliated graphite in latex, onto a rubber membrane, and the response of the skin was characterized. The change in resistance was linear with tensile strain. The role of the padding material was then investigated under indentation by examining three foams and two elastomers. As expected, the padding enhanced energy dissipation as shown by hysteresis in the sensor response, which is linked to its protective function; the hysteresis was comparable for the five padding materials. The padding also provided an unexpected advantage: it magnified the change in resistance compared to that obtained under free displacement in air. While hysteresis in viscoelastic materials can largely be handled with an appropriate model, inconsistency cannot be, and the two elastomers were found to have unacceptably high variability because of micro-cracks and other defects in these materials. On the other hand, foams that had few defects and regular cell sizes gave good consistency across trials and different sensor positions over the padding. Combined with their lighter weight and availability in a wide range of stiffness, we conclude that foams make a better choice for padding of co-robots. (paper)

Morphology of the dorsal lingual papillae in the newborn panther and Asian black bear.

Science.gov (United States)

Emura, S; Hayakawa, D; Chen, H; Shoumura, S

2001-12-01

The dorsal lingual surfaces of a newborn panther (Panthera pardus) and two newborn asian black bears (Selenarctos thibetanus) were examined by scanning electron microscopy (SEM). The tongues of the panther and asian black bear were about 40 mm in length and about 20 mm in width. Filiform, fungiform and vallate papillae were found. The filiform papillae were distributed over the entire dorsal surface of the tongue. In the panther, the filiform papillae on margin of the lingual apex were divided into two shapes which were horny or club-shaped papillae. The filiform papillae on the midportion were larger than those on the lateral region in size. The fungiform papillae also were divided into two shapes which were hemispherical or club-shaped papillae. In the asian black bear, the filiform papillae on the margin of the lingual apex were larger than those on margin of the panther tongue. The vallate papillae in the animals of two species were located on both sides of the posterior end of the lingual body. Each papilla was surrounded by a groove and crescent pad.

Teach yourself visually the new iPad

CERN Document Server

Watson, Lonzell

2012-01-01

A new edition of a bestseller, fully updated on the latest features of the iPad! The evolution of the iPad continues to deliver amazing possibilities, which is exactly why this bestselling guide evolves right along with it! Fully updated with coverage on the latest generation of the iPad, this full-color, step-by-step guide is perfectly suited for anyone who is a visual learner and learns best by visual cues and a tactile interface. You'll learn to access and download books, apps, music, and video content as well as send photos and emails, sync with other devices and services, and confidently

Surface-modified polymeric pads for enhanced performance during chemical mechanical planarization

International Nuclear Information System (INIS)

Deshpande, S.; Dakshinamurthy, S.; Kuiry, S.C.; Vaidyanathan, R.; Obeng, Y.S.; Seal, S.

2005-01-01

The chemical mechanical planarization (CMP) process occurs at an atomic level at the slurry/wafer interface and hence slurries and polishing pads play a critical role in their successful implementation. Polyurethane is a commonly used polymer in the manufacturing of CMP pads. These pads are incompatible with some chemicals present in the CMP slurries, such as hydrogen peroxide. To overcome these problems, Psiloquest has developed new Application Specific Pads (ASP). Surface of such pads has been modified by depositing a thin film of tetraethyl orthosilicate using plasma-enhanced chemical vapor deposition (PECVD) process. In the present study, mechanical properties of such coated pads have been investigated using nanoindentation. The surface morphology and the chemistry of the ASP were studied using scanning electron microcopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy techniques. It was observed that mechanical and chemical properties of the pad top surface are a function of the PECVD coating time. Such PECVD-treated pads are found to be hydrophilic and do not require storage in aqueous media during the not-in-use period. The metal removal rate using such surface-modified polishing pads was found to increase linearly with the PECVD coating time

47 CFR 80.1007 - Bridge-to-bridge radiotelephone installation.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge radiotelephone installation. 80.1007 Section 80.1007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND... Bridge-to-Bridge Act § 80.1007 Bridge-to-bridge radiotelephone installation. Use of the bridge-to-bridge...

21 CFR 884.5435 - Unscented menstrual pad.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Unscented menstrual pad. 884.5435 Section 884.5435 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5435 Unscented menstrual pad. (a)...

Student Perceptions of Classroom Engagement and Learning using iPads

OpenAIRE

Jefferson W. Streepey; Eugenia Fernandez; Timothy T. Diemer

2013-01-01

Many colleges and universities have launched iPad initiatives in an effort to enhance student learning. Despite their rapid adoption, the extent to which iPads increase student engagement and learning is not well understood. This paper reports on a multidisciplinary assessment of student perceptions of engagement and learning using iPads. Student reactions following single and multiple classroom activities using iPads were measured via a survey asking them to rate their learning and engagemen...

Pilot Study of iPad Incorporation Into Graduate Medical Education.

Science.gov (United States)

Lobo, Mark J; Crandley, Edwin F; Rumph, Jake S; Kirk, Susan E; Dunlap, Neal E; Rahimi, Asal S; Turner, A Benton; Larner, James M; Read, Paul W

2013-03-01

Increased documentation and charting requirements are challenging for residents, given duty hour limits. Use of mobile electronic devices may help residents complete these tasks efficiently. To collect initial data on usage rates, information technology (IT) support requirements, and resident use of iPads during training. In this pilot study, we provided 12 residents/fellows from various specialties at the University of Virginia with an iPad with IT support. The system used a virtual private network with access to the institution's electronic health record. Participants were allowed to develop their own methods and systems for personalized iPad use, and after 9 months they provided data on the utility of the iPad. Feedback from the IT team also was obtained. Average iPad use was 2.1 h/d (range, 0.5-6 h/d). The average self-reported reduction in administrative work due to the iPad was 2.7 h/wk (range, 0-9 h/wk). A total of 75% (9 of 12) of the users would recommend universal adoption among residents and fellows. More than 90% (11 of 12) of users reported the iPad would improve communication for coordination of care. A total of 68% (8 of 12) of users reported that an iPad facilitated their activities as educators of medical students and junior residents. Residents cited slow data entry into the electronic health record and hospital areas lacking Wi-Fi connectivity as potential drawbacks to iPad use. The IT team reported minimal support time for device setup, maintenance, and upgrades, and limited security risks. The iPad may contribute to increased clinical efficiency, reduced hours spent on administrative tasks, and enhanced educational opportunities for residents, with minimal IT support.

Morphology and properties of periwinkle shell asbestos-free brake pad

Directory of Open Access Journals (Sweden)

D.S. Yawas

2016-01-01

Full Text Available The development of asbestos-free automotive brake pad using periwinkle shell particles as frictional filler material is presented. This was with a view to exploiting the characteristics of the periwinkle shell, which is largely deposited as a waste, in replacing asbestos which has been found to be carcinogenic. Five sets of brake pads with different sieve size (710–125 μm of periwinkle shell particles with 35% resin were produced using compressive moulding. The physical, mechanical and tribological properties of the periwinkle shell particle-based brake pads were evaluated and compared with the values for the asbestos-based brake pads. The results obtained showed that compressive strength, hardness and density of the developed brake pad samples increased with decreasing the particle size of periwinkle shell from 710 to 125 μm, while the oil soak, water soak and wear rate decreased with decreasing the particle size of periwinkle shell. The results obtained at 125 μm of periwinkle shell particles compared favourably with that of commercial brake pad. The results of this research indicate that periwinkle shell particles can be effectively used as a replacement for asbestos in brake pad manufacture.

Longitudinal Seismic Behavior of a Single-Tower Cable-Stayed Bridge Subjected to Near-Field Earthquakes

Directory of Open Access Journals (Sweden)

J. Yi

2017-01-01

Full Text Available Cable-stayed bridges are quite sensitive to large amplitude oscillations from earthquakes and seismic damage was observed for Shipshaw Bridge and Chi-Lu Bridge during past earthquakes. In order to investigate seismic damage of cable-stayed bridges, a 1 : 20 scale model of a single-tower cable-stayed bridge with A-shaped tower was designed, constructed, and tested on shake tables at Tongji University, China. One typical near-field ground motion was used to excite the model from low to high intensity. Test result showed that severe structural damage occurred at the tower of the model including parallel concrete cracks from bottom to nearly half height of the tower, concrete spalling, and exposed bars at top tower 0.2 m above the section where two skewed legs intersect. Posttest analysis was conducted and compared with test results. It is revealed that the numerical model was able to simulate the seismic damage of the test model by modeling nonlinearity of different components for cable-stayed bridges, namely, the tower, bents, superstructure, cables, and bearings. Numerical analysis also revealed that cable relaxation, which was detected during the test, had limited influence on the overall seismic response of the bridge with maximum error of 12%.

Water data: bad TPC pads, 3.6 µs and 100 ns problems

CERN Document Server

Dydak, F; Nefedov, Y; Wotschack, J; Zhemchugov, A

2004-01-01

Out of the 3972 pads of the HARP TPC, about 9% are 'bad' and not useful for the correct reconstruction of clusters. Bad pads comprise dead pads, noisy pads, and pads with low or undefined amplification. Pads may be bad at one time, but not at another. This memo discusses the sources of information which were used to declare a pad 'bad', and gives the list of bad pads for the water data (runs 19146 to 19301). Also, the 3.6 µs and 100 ns problems of the TPC readout are discussed, including the corrective measures which have been taken.

De implementatie van de iPad in het voortgezet onderwijs

NARCIS (Netherlands)

Marjorie Louwsma; Anneke van Zwol; Klaas Jan Huizing

2012-01-01

Brengt de iPad in het onderwijs meer gebruiksgemak, snelheid en studievermogen? Sowijs deed onderzoek naar de implementatie van de iPad in het voortgezet onderwijs. Wat is de visie van leerlingen en leraren over de introductie van de iPad en wat zijn belangrijke aanbevelingen?

Experimental Study on Post Grouting Bearing Capacity of Large Diameter Bored Piles

Directory of Open Access Journals (Sweden)

Wang Duanduan

2015-01-01

Full Text Available Post grouting can improve the inherent defects such as the formation of the mud cake at pile side and the sediment at pile end in the process of bored pile construction. Thus post grouting has been widely used in Engineering. The purpose of this paper is to research the influences of post grouting to pile bearing capacity more systematically and intuitively. Combined with the static load test of four test piles in Weihe River Bridge test area of new airport highway in Xi’an, the bearing capacity and settlement of routine piles and post grouting piles are comparatively analyzed. The test results show that under the same geological condition, post grouting can improve the properties of pile tip and pile shaft soil of bored piles significantly, enhance the ultimate resistance, improve the ultimate bearing capacity and reduce the pile tip settlement. Then post grouting can aim to optimize pile foundation.

Construction of Daiichi Tamagawa bridge; Daiichi Tamagawa kyoryo no seko

Energy Technology Data Exchange (ETDEWEB)

Watanabe, O.; Tsuyoshi, T. [East Japan Railway Company, Tokyo (Japan); Ota, T.; Sato, S. [Tekken Corp., Tokyo (Japan)

1997-05-30

This paper describes the construction of Daiichi Tamagawa Bridge for JR Tazawako Line, which was reconstructed with the Akita Shinkansen Project apart from the existing line. This bridge is a three-span continuous PC cable stayed bridge. To avoid operation accidents due to snow and ice, independent two-column type with a height of 11 m without beam was employed for the main tower. For the construction of upper part, overhang election construction method was adopted, which can be applied all the year round. The main girder has a single box cross section, and a width of 5.5 m and a beam height of 2.3 m. This was also constructed by the overhang construction method. To reduce the construction period, the main tower was constructed by the precast block construction method. The whole bridge was divided into six blocks by considering the hoist performance of cranes. Reinforcement against bearing pressure and cleavage due to the cable tensile force was conducted by adopting saddle structure for the main tower. Oblique members were jointed with the main girder using lateral beams projected from lateral side of girder. Totally seven PC cables were used for each oblique member. Measurements and management during the overhang construction were also described. The construction was over without problems in August, 1996. This bridge is under test operation using test run vehicles. 2 refs., 20 figs., 7 tabs.

Displacement monitoring and modelling of a high-speed railway bridge using C-band Sentinel-1 data

Science.gov (United States)

Huang, Qihuan; Crosetto, Michele; Monserrat, Oriol; Crippa, Bruno

2017-06-01

Bridge displacement monitoring is one of the key components of bridge structural health monitoring. Traditional methods, usually based on limited sets of sensors mounted on a given bridge, collect point-like deformation information and have the disadvantage of providing incomplete displacement information. In this paper, a Persistent Scatterer Interferometry (PSI) approach is used to monitor the displacements of the Nanjing Dashengguan Yangtze River high-speed railway bridge. Twenty-nine (29) European Space Agency Sentinel-1A images, acquired from April 25, 2015 to August 5, 2016, were used in the PSI analysis. A total of 1828 measurement points were selected on the bridge. The results show a maximum longitudinal displacement of about 150 mm on each side of the bridge. The measured displacements showed a strong correlation with the environmental temperature at the time the images used were acquired, indicating that they were due to thermal expansion of the bridge. At each pier, a regression model based on the PSI-measured displacements was compared with a model based on in-situ measurements. The good agreement of these models demonstrates the capability of the PSI technique to monitor long-span railway bridge displacements. By comparing the modelled displacements and dozens of PSI measurements, we show how the performance of movable bearings can be evaluated. The high density of the PSI measurement points is advantageous for the health monitoring of the entire bridge.

LOAD BEARING CAPACITY OF THE GLASS RAILING ELEMENT

Directory of Open Access Journals (Sweden)

Elizabeta Šamec

2016-02-01

Full Text Available In this paper some basic physical and mechanical properties of glass as structural material are presented. This research is about specifically manufactured glass railing element that will be a part of a pedestrian bridge construction in Zagreb, Croatia. Load bearing capacity test of the glass railing element is conducted within the Faculty of Civil Engineering in Zagreb and obtained experimental results are discussed and compared to the ones provided by the numerical model. Taking into account the behaviour of laminated glass and results of experimental and numerical testing, glass railing element can be regarded as safe.

Pad stress tests with increasing load for the diagnosis of stress urinary incontinence.

Science.gov (United States)

Rimstad, Liv; Larsen, Elsa Skjønhaug; Schiøtz, Hjalmar A; Kulseng-Hanssen, Sigurd

2014-09-01

The aim of the study was to test the ability of pad stress tests with increasing load (supine, jumping on the floor, and jumping on a trampoline) to document stress incontinence in subjectively stress incontinent women. In this prospective study 147 subjectively stress and mixed incontinent women performed consecutively the three pad stress tests with a bladder volume of 300 ml. Nineteen women performed a second trampoline pad stress test to test repeatability of the test. Nine continent women performed a trampoline pad stress test in order to determine if subjectively continent women would leak during the test. Seventy-two women (49%) leaked during the supine, 136 (93%) leaked during the jumping, and 146 (99%) leaked during the trampoline pad stress test. The differences between pad stress tests were significant with P trampoline pad stress tests was high at 0.8. None of the nine continent women leaked during the trampoline pad stress test. The supine pad stress test has low sensitivity and is therefore often falsely negative. The jumping pad stress test is a simple test to perform and is satisfactory for everyday use. Subjectively stress incontinent women who do not leak during the jumping pad stress test may perform a trampoline pad stress test to document stress incontinence. The trampoline pad stress test is also simple to perform and detected leakage in 91% of the women who did not leak during the jumping pad stress test. © 2013 Wiley Periodicals, Inc.

Correlations for Saturation Efficiency of Evaporative Cooling Pads

Science.gov (United States)

Jain, J. K.; Hindoliya, D. A.

2014-01-01

This paper presents some experimental investigations to obtain correlations for saturation efficiency of evaporative cooling pads. Two commonly used materials namely aspen and khus fibers along with new materials namely coconut fibers and palash fibers were tested in a laboratory using suitably fabricated test setup. Simple mathematical correlations have been developed for calculating saturation efficiency of evaporating cooling pads which can be used to predict their performance at any desired mass flow rate. Performances of four different pad materials were also compared using developed correlations. An attempt was made to test two new materials (i.e. fibers of palash wood and coconut) to check their suitability as wetted media for evaporative cooling pads. It was found that Palash wood fibers offered highest saturation efficiency compared to that of other existing materials such as aspen and khus fibers at different mass flow rate of air.

Development and field performance of indy race car head impact padding.

Science.gov (United States)

Melvin, J W; Bock, H; Anderson, K; Gideon, T

2001-11-01

The close-fitting cockpit of the modern Indy car single seat race car has the potential to provide a high level of head and neck impact protection in rear and side impacts. Crash investigation has shown that a wide variety of materials have been used as the padding for these cockpits and, as a result, produced varying outcomes in crashes. Additionally, these pads have not always been positioned for optimal performance. The purpose of this study was to investigate the head impact performance of a variety of energy-absorbing padding materials under impact conditions typical of Indy car rear impacts and to identify superior materials and methods of improving their performance as race car head pads. An extensive series of tests with the helmeted Hybrid III test dummy head and neck on an impact mini-sled was conducted to explore head padding concepts. Following this, a performance specification for a simplified impact test using a rigid headform that simulates the helmeted head was developed and recommendations for performance levels of head padding based on biomechanical data on helmeted head impacts were made. In 1997, during the time that the head pad research was being performed, the Indy Racing League introduced a new chassis specification for their cars. There were a number of rear- and side-impact crashes during that season that resulted in seven severe head injuries. Examples of the head padding in those cars were included in the experimental study. The results of the head pad research were used to specify new padding materials that met the new biomechanical criteria. The placement of the head pads was also changed for better location of the padding. These changes instituted in 1998 have reduced the number of head injuries in crashes similar to or more severe than those of 1997 and have resulted in only occasional moderate head injuries (concussions) in the 1998 and 1999 seasons.

The optimum tension for bridging sutures in transosseous-equivalent rotator cuff repair: a cadaveric biomechanical study.

Science.gov (United States)

Park, Ji Soon; McGarry, Michelle H; Campbell, Sean T; Seo, Hyuk Jun; Lee, Yeon Soo; Kim, Sae Hoon; Lee, Thay Q; Oh, Joo Han

2015-09-01

Transosseous-equivalent (TOE) rotator cuff repair can increase contact area and contact pressure between the repaired cuff tendon and bony footprint and can show higher ultimate loads to failure and smaller gap formation compared with other repair techniques. However, it has been suggested that medial rotator cuff failure after TOE repair may result from increased bridging suture tension. To determine optimum bridging suture tension in TOE repair by evaluating footprint contact and construct failure characteristics at different tensions. Controlled laboratory study. A total of 18 fresh-frozen cadaveric shoulders, randomly divided into 3 groups, were constructed with a TOE configuration using the same medial suture anchor and placing a Tekscan sensing pad between the repaired rotator cuff tendon and footprint. Nine of the 18 shoulders were used to measure footprint contact characteristics. With use of the Tekscan measurement system, the contact pressure and area between the rotator cuff tendon and greater tuberosity were quantified for bridging suture tensions of 60, 90, and 120 N with glenohumeral abduction angles of 0° and 30° and humeral rotation angles of 30° (internal), 0°, and 30° (external). TOE constructs of all 18 shoulders then underwent construct failure testing (cyclic loading and load to failure) to determine the yield load, ultimate load, stiffness, hysteresis, strain, and failure mode at 60 and 120 N of tension. As bridging suture tension increased, contact force, contact pressure, and peak pressure increased significantly at all positions (P .05 for all). Increasing bridging suture tension to over 90 N did not improve contact area but did increase contact force and pressure. Bridging suture tension did not significantly affect ultimate failure loads. Considering the risks of overtensioning bridging sutures, it may be clinically more beneficial to keep bridging suture tension below 90 N. © 2015 The Author(s).

Exploring anatomy and physiology using iPad applications.

Science.gov (United States)

Chakraborty, Tandra R; Cooperstein, Deborah F

2017-11-07

This study examined the use of iPads with anatomy applications (apps) in the laboratory sections of the largest undergraduate course at the university, Anatomy and Physiology, serving more than 300 students. The majority of these students were nursing, exercise science/physical education and biology majors. With a student survey (student opinion) and student practicum grades as metrics, this study determined whether the introduction of this novel mobile technology improved student grades and aided the students in learning the course material. The results indicated that students' grades improved with the introduction of the iPads, and 78% of the students reported that the iPads facilitated their ability to learn the course material. There was a positive association between frequency of app use and standardized mastery of the course material, as students who used the apps more frequently scored higher and indicated that they felt as though they had learned the material more comprehensively. Owning or having an iPad at home did not have a significant effect on the learning of the material. The general consensus by students was that iPad anatomy apps should be used frequently to better develop student understanding of the course material. Anat Sci Educ. © 2017 American Association of Anatomists. © 2017 American Association of Anatomists.

Impact response of US Army and National Football League helmet pad systems

Energy Technology Data Exchange (ETDEWEB)

Moss, W C; King, M J

2011-02-18

Lawrence Livermore National Laboratory [LLNL] was tasked to compare the impact response of NFL helmet pad systems and U.S. Army pad systems compatible with an Advanced Combat Helmet [ACH] at impact velocities up to 20 ft/s. This was a one-year study funded by the U.S. Army and JIEDDO. The Army/JIEDDO point of contact is COL R. Todd Dombroski, DO, JIEDDO Surgeon. LLNL was chosen by committee to perform the research based on prior published computational studies of the mechanical response of helmets and skulls to blast. Our collaborators include the U.S. Army Aeromedical Research Laboratory [USAARL] (a DoD laboratory responsible for impact testing helmets), Team Wendy and Oregon Aero (current and former ACH pad manufacturers), Riddell and Xenith (NFL pad manufacturers), and d3o (general purpose sports pad manufacturer). The manufacturer-supplied pad systems that were studied are shown in the figure below. The first two are the Army systems, which are bilayer foam pads with both hard and soft foam and a water-resistant airtight wrapper (Team Wendy) or a water-resistant airtight coating (Oregon Aero). The next two are NFL pad systems. The Xenith system consists of a thin foam pad and a hollow air-filled cylinder that elastically buckles under load. The Riddell system is a bilayer foam pad that is encased in an inflatable airbag with relief channels to neighboring pads in the helmet. The inflatable airbag is for comfort and provides no enhancement to impact mitigation. The d3o system consists of a rate-sensitive homogeneous dense foam. LLNL performed experiments to characterize the material properties of the individual foam materials and the response of the complete pad systems, to obtain parameters needed for the simulations. LLNL also performed X-ray CT scans of an ACH helmet shell that were used to construct a geometrically accurate computational model of the helmet. Two complementary sets of simulations were performed. The first set of simulations reproduced the

Predict optimize the friction characteristics of brake pads; Brake pad no masatsu tokusei no yosoku to saitekika

Energy Technology Data Exchange (ETDEWEB)

Saotome, H [Nissin Kogyo Co., Tokyo (Japan); Kato, T [The University of Tokyo, Tokyo (Japan)

1997-10-01

The effect of the friction and the wear properties of brake pads were experimentally studied using a test rig of scale of 1/10 of the system used in a commercial car. The experimental data were investigated by the Multiple Regression Analysis and the Neural Network, and the effects of volume % of components on the friction and the wear properties were predicted. In addition the components of brake pads are optimized by Genetic Algorithms. 8 refs., 9 figs., 4 tabs.

47 CFR 80.331 - Bridge-to-bridge communication procedure.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge communication procedure. 80..., Alarm, Urgency and Safety Procedures § 80.331 Bridge-to-bridge communication procedure. (a) Vessels subject to the Bridge-to-Bridge Act transmitting on the designated navigational frequency must conduct...

Computerized spiral analysis using the iPad.

Science.gov (United States)

Sisti, Jonathan A; Christophe, Brandon; Seville, Audrey Rakovich; Garton, Andrew L A; Gupta, Vivek P; Bandin, Alexander J; Yu, Qiping; Pullman, Seth L

2017-01-01

Digital analysis of writing and drawing has become a valuable research and clinical tool for the study of upper limb motor dysfunction in patients with essential tremor, Parkinson's disease, dystonia, and related disorders. We developed a validated method of computerized spiral analysis of hand-drawn Archimedean spirals that provides insight into movement dynamics beyond subjective visual assessment using a Wacom graphics tablet. While the Wacom tablet method provides robust data, more widely available mobile technology platforms exist. We introduce a novel adaptation of the Wacom-based method for the collection of hand-drawn kinematic data using an Apple iPad. This iPad-based system is stand-alone, easy-to-use, can capture drawing data with either a finger or capacitive stylus, is precise, and potentially ubiquitous. The iPad-based system acquires position and time data that is fully compatible with our original spiral analysis program. All of the important indices including degree of severity, speed, presence of tremor, tremor amplitude, tremor frequency, variability of pressure, and tightness are calculated from the digital spiral data, which the application is able to transmit. While the iPad method is limited by current touch screen technology, it does collect data with acceptable congruence compared to the current Wacom-based method while providing the advantages of accessibility and ease of use. The iPad is capable of capturing precise digital spiral data for analysis of motor dysfunction while also providing a convenient, easy-to-use modality in clinics and potentially at home. Copyright © 2016 Elsevier B.V. All rights reserved.

Fibrous scar in the infrapatellar fat pad after arthroscopy. MR imaging

International Nuclear Information System (INIS)

Tang, Guangyu; Niitsu, Mamoru; Ikeda, Kotaro; Itai, Yuji; Endo, Hideho

2000-01-01

We describe the MR appearance of fibrous scars in the infrapatellar fat pad after arthroscopy. The subjects were 96 patients who underwent arthroscope-assisted anterior cruciate ligament (ACL) reconstruction and were examined by oblique sagittal MR imaging at different follow-up intervals. Two observers evaluated the characteristics of the fibrous scars in the infrapatellar fat pad. All fibrous scars with low signal intensity were accentuated at the portal and coursed horizontally through the infrapatellar fat pad. The fibrous scar within the fat pad occurred and peaked within 6 months after arthroscopy. It then subsided gradually and had disappeared by one year later in nearly half of the patients. Identifying MR imaging characteristics of fibrous scars in the fat pad after arthroscopy may be clinically helpful to differentiate these scars from other abnormalities that involve the infrapatellar fat pad. (author)

Fibrous scar in the infrapatellar fat pad after arthroscopy. MR imaging

Energy Technology Data Exchange (ETDEWEB)

Tang, Guangyu; Niitsu, Mamoru; Ikeda, Kotaro; Itai, Yuji [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine; Endo, Hideho

2000-02-01

We describe the MR appearance of fibrous scars in the infrapatellar fat pad after arthroscopy. The subjects were 96 patients who underwent arthroscope-assisted anterior cruciate ligament (ACL) reconstruction and were examined by oblique sagittal MR imaging at different follow-up intervals. Two observers evaluated the characteristics of the fibrous scars in the infrapatellar fat pad. All fibrous scars with low signal intensity were accentuated at the portal and coursed horizontally through the infrapatellar fat pad. The fibrous scar within the fat pad occurred and peaked within 6 months after arthroscopy. It then subsided gradually and had disappeared by one year later in nearly half of the patients. Identifying MR imaging characteristics of fibrous scars in the fat pad after arthroscopy may be clinically helpful to differentiate these scars from other abnormalities that involve the infrapatellar fat pad. (author)

Conformation and elasticity of a charged polymer chain bridging two nanoparticles

International Nuclear Information System (INIS)

Nowicki, W.; Nowicka, G.

2013-01-01

A complex composed of a charged flexible polymer chain irreversibly attached with its ends to surfaces of two nanoparticles was investigated using the Metropolis Monte Carlo method on a simple cubic lattice. The simulations were performed in the presence of explicit ions. The bridging chain and the nanoparticles bearing the same and the opposite sign charges were considered. Changes in the free energy of the complex upon its stretching or compression, together with the magnitude of the elastic force, were examined. The relative roles of energetic and entropic effects in determining the properties of the complex were identified. Also, the adsorption of charged monomers on the opposite-sign charged nanoparticles and its influence on the examined quantities was studied. Moreover, a simple semi-analytical approach to the thermodynamics of the polymer bridge was derived

Microhabitat features influencing habitat use by Florida black bears

Directory of Open Access Journals (Sweden)

Dana L. Karelus

2018-01-01

Full Text Available Understanding fine-scale habitat needs of species and the factors influencing heterogeneous use of habitat within home range would help identify limiting resources and inform habitat management practices. This information is especially important for large mammals living in fragmented habitats where resources may be scarcer and more patchily distributed than in contiguous habitats. Using bihourly Global Position System (GPS location data collected from 10 individuals during 2011–2014, we investigated microhabitat features of areas within home ranges that received high vs. low intensity of use by Florida black bears (Ursus americanus floridanus in north-central, Florida. We identified areas receiving high and low levels of use by bears based on their utilization distributions estimated with the dynamic Brownian bridge movement model, and performed vegetation sampling at bear locations within high- and low-use areas. Using univariate analyses and generalized linear mixed models, we found that (1 canopy cover, visual obstruction, and hardwood density were important in defining high-use sites; (2 the probability of high use was positively associated with principal components that represented habitat closer to creeks and with high canopy and shrub cover and higher hardwood densities, likely characteristic of forested wetlands; and (3 the probability of high use was, to a lesser extent, associated with principal components that represented habitat with high canopy cover, high pine density, and low visual obstruction and hardwood density; likely representing sand pine and pine plantations. Our results indicate that the high bear-use sites were in forested wetlands, where cover and food resources for bears are likely to occur in higher abundance. Habitat management plans whereby bears are a focal species should aim to increase the availability and quality of forested wetlands. Keywords: Habitat selection, Heterogeneous habitat use, Forest management

Perceptions and use of iPad technology by pharmacy practice faculty members.

Science.gov (United States)

DiVall, Margarita V; Zgarrick, David P

2014-04-17

To explore the potential of tablet technology to address the specific workload challenges of pharmacy practice faculty members and to evaluate tablet usage after a department-wide iPad initiative. After conducting a needs assessment to determine pharmacy faculty attitudes towards tablet technology and to identify potential usage scenarios, all faculty members in a department of pharmacy practice received an iPad. After iPad distribution, training sessions and virtual tutorials were provided. An anonymous survey was administered to evaluate the pilot. The needs assessment survey revealed positive attitudes towards iPad technology, identified use scenarios, and led to a department-wide iPad pilot program. Most faculty members used iPads for connectivity with students (86%), paper/project annotation (68%), assessment (57%), and demonstration of tools used in practice (36%). For teaching, 61% of faculty members used iPads in seminars/laboratories, 57% used iPads in the experiential setting, and 43% used iPads in the classroom. Use of iPads for patient-care activities varied and depended on site support for mobile technology. The 23 faculty members with external practice sites used iPads to a greater extent and had more positive attitudes towards this technology compared with campus-based faculty members. Integration of tablet technology into the pharmacy education setting resulted in faculty-reported increased productivity and decreased paper waste. It also allowed faculty members to experiment with new teaching strategies in the classroom and experiential setting. Administrators at institutions exploring the use of tablet technology should allocate resources based on faculty needs and usage patterns.

Launch Pad in a Box

Science.gov (United States)

Mantovani, James; Tamasy, Gabor; Mueller, Rob; Townsend, Van; Sampson, Jeff; Lane, Mike

2016-01-01

NASA Kennedy Space Center (KSC) is developing a new deployable launch system capability to support a small class of launch vehicles for NASA and commercial space companies to test and launch their vehicles. The deployable launch pad concept was first demonstrated on a smaller scale at KSC in 2012 in support of NASA Johnson Space Center's Morpheus Lander Project. The main objective of the Morpheus Project was to test a prototype planetary lander as a vertical takeoff and landing test-bed for advanced spacecraft technologies using a hazard field that KSC had constructed at the Shuttle Landing Facility (SLF). A steel pad for launch or landing was constructed using a modular design that allowed it to be reconfigurable and expandable. A steel flame trench was designed as an optional module that could be easily inserted in place of any modular steel plate component. The concept of a transportable modular launch and landing pad may also be applicable to planetary surfaces where the effects of rocket exhaust plume on surface regolith is problematic for hardware on the surface that may either be damaged by direct impact of high speed dust particles, or impaired by the accumulation of dust (e.g., solar array panels and thermal radiators). During the Morpheus free flight campaign in 2013-14, KSC performed two studies related to rocket plume effects. One study compared four different thermal ablatives that were applied to the interior of a steel flame trench that KSC had designed and built. The second study monitored the erosion of a concrete landing pad following each landing of the Morpheus vehicle on the same pad located in the hazard field. All surfaces of a portable flame trench that could be directly exposed to hot gas during launch of the Morpheus vehicle were coated with four types of ablatives. All ablative products had been tested by NASA KSC and/or the manufacturer. The ablative thicknesses were measured periodically following the twelve Morpheus free flight tests

Diagnostic accuracy of heel pad palpation - A phantom study

DEFF Research Database (Denmark)

Torp-Pedersen, Søren; Matteoli, Sara; Wilhjelm, Jens E.

2008-01-01

Falanga torture involves repetitive blunt trauma to the soles of the feet and typically leaves few detectable changes. Reduced elasticity in the heel pads has been reported as characteristic sequelae and palpatory testing of heel pad elasticity is therefore part of medicolegal assessment of alleged...... torture victims. The goal was to test the accuracy of two experienced investigators in determining whether a heel pad model was soft, medium or hard. The skin-to-bone distance in the models varied within the human range....

Pad use and patient reported bother from urinary leakage after radical prostatectomy.

Science.gov (United States)

Wallerstedt, Anna; Carlsson, Stefan; Nilsson, Andreas E; Johansson, Eva; Nyberg, Tommy; Steineck, Gunnar; Wiklund, N Peter

2012-01-01

To better understand clinically significant definitions of urinary incontinence we investigated the relationship between urinary leakage and patient reported bother from urinary leakage. A consecutive series of 1,411 men who underwent radical prostatectomy at Karolinska University Hospital, Stockholm, Sweden, from 2002 to 2006 were invited to complete a study specific questionnaire with questions on pad status, urinary leakage and bother from urinary leakage. Questionnaires were received from 1,179 men with a followup of greater than 1 year (median 2.2). Results showed that even a small amount of urinary leakage resulted in a high risk of urinary bother. Of 775 survivors 46 (6%) reporting 0 pads indicated moderate or much bother compared to 38 of 123 (31%) who reported using a security pad. When comparing the 2 groups, the risk of bother from urinary leakage was more than 5 times higher in the safety pad vs the 0 pad group (RR 5.2, 95% CI 3.5-7.7). As the number of pads increased, we noted a higher bother risk. Cross-tabulation of pad use and urinary leakage revealed wide variation in pad requirements despite the same answer to urinary leakage questions. If the definition of continence is based on pad use, for example safety pads, a certain number of men who report moderate or much bother from urinary leakage will be defined as continent. Our results also show that for each stated rate of urinary leakage men prove to have a major variation in the pad requirement. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Validation of an iPad test of letter contrast sensitivity.

Science.gov (United States)

Kollbaum, Pete S; Jansen, Meredith E; Kollbaum, Elli J; Bullimore, Mark A

2014-03-01

An iPad-based letter contrast sensitivity test was developed (ridgevue.com) consisting of two letters on each page of an iBook. The contrast decreases from 80% (logCS = 0.1) to 0.5% (logCS = 2.3) by 0.1 log units per page. The test was compared to the Pelli-Robson Test and the Freiburg Acuity and Contrast Test. Twenty normally sighted subjects and 20 low-vision subjects were tested monocularly at 1 m using each test wearing their habitual correction. After a 5-minute break, subjects were retested with each test in reverse order. Two different letter charts were used for both the Pelli-Robson and iPad tests, and the order of testing was varied systematically. For the Freiburg test, the target was a variable contrast Landolt C presented at eight possible orientations and used a 30-trial Best PEST procedure. Repeatability and agreement were assessed by determining the 95% limits of agreement (LoA) ± 1.96 SD of the differences between administrations or tests. All three tests showed good repeatability in terms of the 95% LoA: iPad = ± 0.19, Pelli-Robson = ± 0.19, and Freiburg = ± 0.15. The iPad test showed good agreement with the Freiburg test with similar mean (± SD) logCS (iPad = 1.98 ± 0.11, Freiburg = 1.96 ± 0.06) and with narrow 95% LoA (± 0.24), but the Pelli-Robson test gave significantly lower values (1.65 ± 0.04). Low-vision subjects had slightly poorer repeatability (iPad = ± 0.24, Pelli-Robson = ± 0.23, Freiburg = ± 0.21). Agreement between the iPad and Freiburg tests was good (iPad = 1.45 ± 0.40, Freiburg = 1.54 ± 0.37), but the Pelli-Robson test gave significantly lower values (1.30 ± 0.30). The iPad test showed similar repeatability and may be a rapid and convenient alternative to some existing measures. The Pelli-Robson test gave lower values than the other tests.

Effect of comfort pads and incubator design on neonatal radiography

Energy Technology Data Exchange (ETDEWEB)

Jiang, Xia; Baad, Michael; Reiser, Ingrid; Feinstein, Kate A.; Lu, Zhengfeng [University of Chicago Medicine, Department of Radiology, Chicago, IL (United States)

2016-01-15

There has been increasing interest in patient dose reduction in neonatal intensive care units. Removing comfort pads for radiography has been identified as a potential means to decrease patient dose. To assess the effect of comfort pads and support trays on detector entrance exposure (DEE) and image quality for neonatal radiography, and its implication for patient dose. Comfort pads and support trays from three incubator and warmer systems were examined. The attenuation of the primary beam by these structures was measured using a narrow beam geometry. Their effect on DEE and image quality was then assessed using typical neonatal chest radiography techniques with three configurations: (1) both the comfort pad and support included in the beam, (2) only the support tray included and (3) both the comfort pad and support tray removed. Comfort pads and support trays were found to attenuate the primary beam by 6-15%. Eliminating these structures from the X-ray beam's path was found to increase the detector entrance exposure by 28-36% and increase contrast-to-noise ratio by more than 21%, suggesting room for patient dose reduction when the same image quality is maintained. Comfort pads and tray support devices can have a considerable effect on DEE and image quality, with large variations among different incubator designs. Positioning the image detector directly underneath neonatal patients for radiography is a potential means for patient dose reduction. However, such benefit should be weighed against the risks of moving the patient. (orig.)

Effect of comfort pads and incubator design on neonatal radiography

International Nuclear Information System (INIS)

Jiang, Xia; Baad, Michael; Reiser, Ingrid; Feinstein, Kate A.; Lu, Zhengfeng

2016-01-01

There has been increasing interest in patient dose reduction in neonatal intensive care units. Removing comfort pads for radiography has been identified as a potential means to decrease patient dose. To assess the effect of comfort pads and support trays on detector entrance exposure (DEE) and image quality for neonatal radiography, and its implication for patient dose. Comfort pads and support trays from three incubator and warmer systems were examined. The attenuation of the primary beam by these structures was measured using a narrow beam geometry. Their effect on DEE and image quality was then assessed using typical neonatal chest radiography techniques with three configurations: (1) both the comfort pad and support included in the beam, (2) only the support tray included and (3) both the comfort pad and support tray removed. Comfort pads and support trays were found to attenuate the primary beam by 6-15%. Eliminating these structures from the X-ray beam's path was found to increase the detector entrance exposure by 28-36% and increase contrast-to-noise ratio by more than 21%, suggesting room for patient dose reduction when the same image quality is maintained. Comfort pads and tray support devices can have a considerable effect on DEE and image quality, with large variations among different incubator designs. Positioning the image detector directly underneath neonatal patients for radiography is a potential means for patient dose reduction. However, such benefit should be weighed against the risks of moving the patient. (orig.)

Proof Pad: A New Development Environment for ACL2

Directory of Open Access Journals (Sweden)

Caleb Eggensperger

2013-04-01

Full Text Available Most software development projects rely on Integrated Development Environments (IDEs based on the desktop paradigm, with an interactive, mouse-driven user interface. The standard installation of ACL2, on the other hand, is designed to work closely with Emacs. ACL2 experts, on the whole, like this mode of operation, but students and other new programmers who have learned to program with desktop IDEs often react negatively to the process of adapting to an unfamiliar form of interaction. This paper discusses Proof Pad, a new IDE for ACL2. Proof Pad is not the only attempt to provide ACL2 IDEs catering to students and beginning programmers. The ACL2 Sedan and DrACuLa systems arose from similar motivations. Proof Pad builds on the work of those systems, while also taking into account the unique workflow of the ACL2 theorem proving system. The design of Proof Pad incorporated user feedback from the outset, and that process continued through all stages of development. Feedback took the form of direct observation of users interacting with the IDE as well as questionnaires completed by users of Proof Pad and other ACL2 IDEs. The result is a streamlined interface and fast, responsive system that supports using ACL2 as a programming language and a theorem proving system. Proof Pad also provides a property-based testing environment with random data generation and automated interpretation of properties as ACL2 theorem definitions.

A Study on Assessment Method of Traffic Load Effect of Bridge in Service

Science.gov (United States)

Ling, Pan; Dajian, Han

2010-05-01

Because of overloading usually occur in highway in China today, it is found that the traffic load and the load effects given by Specification for Inspection and Evaluation of Load-bearing Capacity of Highway Bridge[1] cannot be adequately estimated. Especially, the extreme values in a service period can not be predicted. In this paper, a model is first developed for a better estimation of the actual traffic flow, as well as the service load effect level of a bridge. Based on a five-day collection data of the vehicle samples passing through the exit of Guangyuan to Shahe of the North-Ring Highway in Guangzhou, The Qiaole Bridge of the highway is taken as an example to illustrate the assessment model. Then, a threshold model is applied to estimate the tail distribution of the maximum load effect of a fleet. And threshold point process is used to infer the maximum value distribution for prediction of the load effect level of the bridge in a future time period. Finally, a 0.95 quantile is obtained to compare with the result given by specification[1]. The results show that the assessment method proposed in this paper is valid and feasible.

Exploring the use of iPads in Danish schools

DEFF Research Database (Denmark)

Khalid, Md. Saifuddin; Jurisic, Olivera; Kristensen, Henrik Stein

2014-01-01

Mobile devices, especially the integration and adoption of iPads in school classrooms, is gaining emphasis across the research and development forums of academic, policy, organizational, political, and public spheres. In April 2012, the Danish government announced that they would allocate DKK 500...... of integrating and adopting desktop computers and other educational technologies. However, there are some unique advantages that iPad and other mobile devices can enable through apps, readiness, etc. Policies and strategies should be adopted to combine training and maintenance along with ensuring access to iPads....

Bearing system

Science.gov (United States)

Kapich, Davorin D.

1987-01-01

A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

Development, implementation and operational experience with 900 mm R1T pocket-type bearings at Oskarshamn unit 3 nuclear steam turbine generator

International Nuclear Information System (INIS)

Peel, P.; Roos, A.

2015-01-01

The Oskarshamn unit 3 nuclear steam turbine generator in Sweden is operated by OKG and, following the extensive PULS upgrade project, delivers an increased rated output of 1450 MW making it the most powerful BWR unit worldwide. Several turbine bearing incidents occurred in 2009 and 2010, which initiated a detailed root cause analysis to determine the reasons and propose appropriate mitigation measures to ensure reliable unit operation. Together with OKG, ALSTOM Power implemented a short-term solution to operate the unit over the winter period of 2010-11. Subsequently, during the annual outage in June 2011, a permanent solution involving a R1T pocket-type bearing design was installed at three shaft-line positions. Since the 1980's, R1T bearings with diameters from 250 to 670 mm have been operating in numerous full-speed (3000/3600 rpm) steam turbine generators. However, this was the first application of a R1T bearing developed at a diameter of 900 mm and for half-speed operation. This paper presents an overview of the bearing development and details the successful operational feedback gathered to date on the three installed bearings. In comparison with the three tilting pad bearing design, which has typically been used on large half-speed ALSTOM Power steam turbine generators to date, it confirms the R1T bearing design as a viable alternative. (authors)

Myocardial Bridge

Science.gov (United States)

... Center > Myocardial Bridge Menu Topics Topics FAQs Myocardial Bridge En español Your heart is made of muscle, ... surface of the heart. What is a myocardial bridge? A myocardial bridge is a band of heart ...

Operating experience of gas bearing helium circulators in HTGR development facility

International Nuclear Information System (INIS)

Shimomura, H.; Kawaji, S.; Fujisaki, K.; Ihizuka, T.

1988-01-01

The large scale helium gas test facility (HENDEL) has been constructed and operated since March 1982 at the Japan Atomic Energy Research Institute to develop HTGR components. The five electric driven gas circulators with dynamic gas bearings are used to circulate the helium gas of 4MPa and 400 deg. C in loops for their compactness, gas tightness, easy maintenance and free from gas contamination. All of these circulators are variable speed types of 3,000 to 12,000 rpm and have the same gas bearings and electric motors. The four machines among them are equipped with centrifugal impeller and one other machine has regenerative type, and the weight of both type rotors are nearly the same. After the troubles and repairing, both type of circulators were tested and the vibration characteristics were measured as preventing maintenance. From the test and measurements of the circulators, it was presumed that the first trouble on regenerative type was caused from excess unbalance force by falling off of a small pin from the rotating part and the second severe trouble on it was caused by the whipping in gas bearing. The static load on tilting pads indicated close relations to occurrence of the whirling through the measurements. It is recognized that fine balancing of the rotors and delicate clearance adjustment of the bearings are very important for the rotor stability and that the mechanism should be designed and machined so precise as to be adjustable. As the gas bearing would be damaged in an instantaneously short time, the monitoring technique for it should be so fast and predictive as to prevent serious damage. Through the tests, the vibration spectrum monitoring method seems to be predictive and useful for early detection of the shaft instability. It will be concluded that the gas bearing machine is an excellent system in its design philosophy, however, it also needs highly precise machining and delicate maintenance technique. 4 refs, 10 figs, 1 tab

Effect of conditioner load on the polishing pad surface during chemical mechanical planarization process

Energy Technology Data Exchange (ETDEWEB)

Shin, Cheol Min; Qin, Hong Yi; Hong, Seok Jun; Jeon, Sang Hyuk; Kulkarni, Atul; Kim, Tae Sun [Sungkyunkwan University, Suwon (Korea, Republic of)

2016-12-15

During the Chemical mechanical planarization (CMP), the pad conditioning process can affect the pad surface characteristics. Among many CMP process parameters, the improper applied load on the conditioner arm may have adverse effects on the polyurethane pad. In this work, we evaluated the pad surface properties under the various conditioner arm applied during pad conditioning process. The conditioning pads were evaluated for surface topography, surface roughness parameters such as Rt and Rvk and Material removal rate (MRR) and within-wafer non-uniformity after wafer polishing. We observed that, the pad asperities were collapsed in the direction of conditioner rotation and blocks the pad pores applied conditioner load. The Rvk value and MRR were founded to be in relation with 4 > 1 > 7 kgF conditioner load. Hence, this study shows that, 4 kgF applied load by conditioner is most suitable for the pad conditioning during CMP.

21 CFR 890.3790 - Cane, crutch, and walker tips and pads.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cane, crutch, and walker tips and pads. 890.3790 Section 890.3790 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES..., crutch, and walker tips and pads. (a) Identification. Cane, crutch, and walker tips and pads are rubber...

A combination drift chamber/pad chamber for very high readout rates

International Nuclear Information System (INIS)

Spiegel, L.; Cataldi, G.; Elia, V.; Mazur, P.; Murphy, C.T.; Smith, R.P.; Yang, W.; Alexopoulos, T.; Durandet, C.; Erwin, A.; Jennings, J.; Antoniazzi, L.; Introzzi, G.; Lanza, A.; Liguori, G.; Torre, P.; Arenton, M.; Conetti, S.; Cox, B.; Dukes, E.; Golovatyuk, V.; Hanlet, P.; McManus, A.; Nelson, K.; Recagni, M.; Segal, J.; Sun, J.; Ballagh, C.; Bingham, H.; Kaeding, T.; Lys, J.; Misawa, S.; Blankman, A.; Borodin, S.; Kononenko, W.; Newcomer, M.; Selove, W.; Trojak, T.; VanBerg, R.; Zhang, S.N.; Block, M.; Corti, G.; LeCompte, T.; Rosen, J.; Yao, T.; Boden, A.; Cline, D.; Ramachandran, S.; Rhoades, J.; Tokar, S.; Budagov, J.; Tsyganov, E.; Cao, Z.L.; He, M.; Wang, C.; Wei, C.; Zhang, N.; Chen, T.Y.; Yao, N.; Clark, K.; Jenkins, M.; Cooper, M.; Creti, P.; Gorini, E.; Grancagnolo, F.; Panareo, M.; Fortney, L.; Kowald, W.; Haire, M.; Judd, D.; Turnbull, L.; Wagoner, D.; Lau, K.; Mo, G.; Trischuk, J.

1991-11-01

Six medium-sized (∼1 x 2 m 2 ) drift chambers with pad and stripe readout have been constructed for and are presently operating in Fermi National Accelerator Laboratory experiment E-771. Each chamber module actually represents a pair of identical planes: two sets of anode wires, two sets of stripes, and two sets of pads. The wire planes are read out separately and represent X measurements in the coordinate system of the experiment. The twin stripe and pad planes are internally paired within the chamber modules; stripe signals represent Y measurements and pad signals combination X and Y measurements. Signals which develop on the stripes and pads are mirror (but inverted) images of what is seen on the wires. In addition to being used in the off-line pattern recognition, pad signals are also used as inputs to an on-line high transverse momentum (pt) trigger processor. While the techniques involved in the design and construction of the chambers are not novel, they may be of interest to experiments contemplating very large area, high rate chambers for future spectrometers

A combination drift chamber/pad chamber for very high readout rates

Energy Technology Data Exchange (ETDEWEB)

Spiegel, L.; Cataldi, G.; Elia, V.; Mazur, P.; Murphy, C.T.; Smith, R.P.; Yang, W. (Fermi National Accelerator Lab., Batavia, IL (United States)); Alexopoulos, T.; Durandet, C.; Erwin, A.; Jennings, J. (Wisconsin Univ., Madison, WI (United States)); Antoniazzi, L.; Introzzi, G.; Lanza, A.; Liguori, G.; Torre, P. (Pavia Univ. (Italy) Istituto Nazionale di Fisica Nucleare, Rome (Italy)); Arenton, M.; Conetti, S.

1991-11-01

Six medium-sized ({approx}1 {times} 2 m{sup 2}) drift chambers with pad and stripe readout have been constructed for and are presently operating in Fermi National Accelerator Laboratory experiment E-771. Each chamber module actually represents a pair of identical planes: two sets of anode wires, two sets of stripes, and two sets of pads. The wire planes are read out separately and represent X measurements in the coordinate system of the experiment. The twin stripe and pad planes are internally paired within the chamber modules; stripe signals represent Y measurements and pad signals combination X and Y measurements. Signals which develop on the stripes and pads are mirror (but inverted) images of what is seen on the wires. In addition to being used in the off-line pattern recognition, pad signals are also used as inputs to an on-line high transverse momentum (pt) trigger processor. While the techniques involved in the design and construction of the chambers are not novel, they may be of interest to experiments contemplating very large area, high rate chambers for future spectrometers.

Neurosurgical simulation by interactive computer graphics on iPad.

Science.gov (United States)

Maruyama, Keisuke; Kin, Taichi; Saito, Toki; Suematsu, Shinya; Gomyo, Miho; Noguchi, Akio; Nagane, Motoo; Shiokawa, Yoshiaki

2014-11-01

Presurgical simulation before complicated neurosurgery is a state-of-the-art technique, and its usefulness has recently become well known. However, simulation requires complex image processing, which hinders its widespread application. We explored handling the results of interactive computer graphics on the iPad tablet, which can easily be controlled anywhere. Data from preneurosurgical simulations from 12 patients (4 men, 8 women) who underwent complex brain surgery were loaded onto an iPad. First, DICOM data were loaded using Amira visualization software to create interactive computer graphics, and ParaView, another free visualization software package, was used to convert the results of the simulation to be loaded using the free iPad software KiwiViewer. The interactive computer graphics created prior to neurosurgery were successfully displayed and smoothly controlled on the iPad in all patients. The number of elements ranged from 3 to 13 (mean 7). The mean original data size was 233 MB, which was reduced to 10.4 MB (4.4% of original size) after image processing by ParaView. This was increased to 46.6 MB (19.9%) after decompression in KiwiViewer. Controlling the magnification, transfer, rotation, and selection of translucence in 10 levels of each element were smoothly and easily performed using one or two fingers. The requisite skill to smoothly control the iPad software was acquired within 1.8 trials on average in 12 medical students and 6 neurosurgical residents. Using an iPad to handle the result of preneurosurgical simulation was extremely useful because it could easily be handled anywhere.

An Improved Cambridge Filter Pad Extraction Methodology to Obtain More Accurate Water and “Tar” Values: In Situ Cambridge Filter Pad Extraction Methodology

Directory of Open Access Journals (Sweden)

Ghosh David

2014-07-01

Full Text Available Previous investigations by others and internal investigations at Philip Morris International (PMI have shown that the standard trapping and extraction procedure used for conventional cigarettes, defined in the International Standard ISO 4387 (Cigarettes -- Determination of total and nicotine-free dry particulate matter using a routine analytical smoking machine, is not suitable for high-water content aerosols. Errors occur because of water losses during the opening of the Cambridge filter pad holder to remove the filter pad as well as during the manual handling of the filter pad, and because the commercially available filter pad holder, which is constructed out of plastic, may adsorb water. This results in inaccurate values for the water content, and erroneous and overestimated values for Nicotine Free Dry Particulate Matter (NFDPM. A modified 44 mm Cambridge filter pad holder and extraction equipment which supports in situ extraction methodology has been developed and tested. The principle of the in situ extraction methodology is to avoid any of the above mentioned water losses by extracting the loaded filter pad while kept in the Cambridge filter pad holder which is hermetically sealed by two caps. This is achieved by flushing the extraction solvent numerous times through the hermetically sealed Cambridge filter pad holder by means of an in situ extractor. The in situ methodology showed a significantly more complete water recovery, resulting in more accurate NFDPM values for high-water content aerosols compared to the standard ISO methodology. The work presented in this publication demonstrates that the in situ extraction methodology applies to a wider range of smoking products and smoking regimens, whereas the standard ISO methodology only applies to a limited range of smoking products and smoking regimens, e.g., conventional cigarettes smoked under ISO smoking regimen. In cases where a comparison of yields between the PMI HTP and

iPads in Inclusive Classrooms: Ecologies of Learning

Science.gov (United States)

Meyer, Bente

2013-01-01

This paper builds on data from a project where iPads were used in a lower secondary school in Denmark to support school development and inclusive learning environments. The paper explores how iPads enter into and work as part of an ecology of learning in five classes in lower secondary school. The paper argues that we should disengage approaches…

iPad Use in Seventh Grade Math: Parent and Student Perceptions

Science.gov (United States)

Corbett, Robin

2015-01-01

The purpose of this qualitative research study was to compare student and parental perceptions of mobile technology use, specifically iPads, in seventh grade math classrooms and at home. How students and parents perceive the use of iPads within the seventh grade math classroom and how students and parents perceive the influence of iPad use at home…

Tentative provisions for seismic design of base isolated buildings in France

International Nuclear Information System (INIS)

Gantenbein, F.; Bisch, P.

1991-01-01

This paper presents Chapter 22 of the AFPS (French Earthquake Engineering Association) Recommendations, devoted to aseismic bearing pads. This chapter gives general rules applicable to any kind of pads, and specific rules for hooped elastomer pads. It contains specifications for general or detailed arrangements when aseismic bearing pads are used, calculation procedures (in particular, a simplified method), and a technical validation procedure for new designs of pads

Barriers to the Integration and Adoption of iPads in Schools

DEFF Research Database (Denmark)

Khalid, Md. Saifuddin; Kilic, Gökce; Christoffersen, Jeanette

2015-01-01

iPad, with its Apple platform and interoperability-dependent material conditions, bring complex barriers in its adoption and integration in secondary education system as a learning tool. In the schools’ context, it is an emerging educational technology for its affordances supporting collaborative...... learning. This systematic literature review on the barriers to the integration of iPad in primary and secondary schools is based on 13 peer-reviewed and full-text articles. The paper discusses what are the challenges in using iPad as a learning tool in primary and secondary educational settings....... The identified barriers are discussed in three broad categories or stages of innovation process in an educational context: basic challenges with the tool, barriers to the integration of the iPad in a school setting, and barriers in the use of the iPad....

Control and sensor techniques for PAD servo motor drive

DEFF Research Database (Denmark)

Zsurzsan, Tiberiu-Gabriel; Zhang, Zhe; Andersen, Michael A. E.

2015-01-01

The Piezoelectric Actuator Drive (PAD) is a new type of electrical motor that employs piezoelectric multilayer actuators coupled with a form-fitted micro-mechanical gearing to generate rotary motion. The PAD is precise, having a positioning error of less than 2 arc-seconds. Its typical output...

Simulating pad-electrodes with high-definition arrays in transcranial electric stimulation

Science.gov (United States)

Kempe, René; Huang, Yu; Parra, Lucas C.

2014-04-01

Objective. Research studies on transcranial electric stimulation, including direct current, often use a computational model to provide guidance on the placing of sponge-electrode pads. However, the expertise and computational resources needed for finite element modeling (FEM) make modeling impractical in a clinical setting. Our objective is to make the exploration of different electrode configurations accessible to practitioners. We provide an efficient tool to estimate current distributions for arbitrary pad configurations while obviating the need for complex simulation software. Approach. To efficiently estimate current distributions for arbitrary pad configurations we propose to simulate pads with an array of high-definition (HD) electrodes and use an efficient linear superposition to then quickly evaluate different electrode configurations. Main results. Numerical results on ten different pad configurations on a normal individual show that electric field intensity simulated with the sampled array deviates from the solutions with pads by only 5% and the locations of peak magnitude fields have a 94% overlap when using a dense array of 336 electrodes. Significance. Computationally intensive FEM modeling of the HD array needs to be performed only once, perhaps on a set of standard heads that can be made available to multiple users. The present results confirm that by using these models one can now quickly and accurately explore and select pad-electrode montages to match a particular clinical need.

Extending Counter-streaming Motion from an Active Region Filament to a Sunspot Light Bridge

Science.gov (United States)

Wang, Haimin; Liu, Rui; Li, Qin; Liu, Chang; Deng, Na; Xu, Yan; Jing, Ju; Wang, Yuming; Cao, Wenda

2018-01-01

We analyze high-resolution observations from the 1.6 m telescope at Big Bear Solar Observatory that cover an active region filament. Counter-streaming motions are clearly observed in the filament. The northern end of the counter-streaming motions extends to a light bridge, forming a spectacular circulation pattern around a sunspot, with clockwise motion in the blue wing and counterclockwise motion in the red wing, as observed in the Hα off-bands. The apparent speed of the flow is around 10–60 km s‑1 in the filament, decreasing to 5–20 km s‑1 in the light bridge. The most intriguing results are the magnetic structure and the counter-streaming motions in the light bridge. Similar to those in the filament, the magnetic fields show a dominant transverse component in the light bridge. However, the filament is located between opposed magnetic polarities, while the light bridge is between strong fields of the same polarity. We analyze the power of oscillations with the image sequences of constructed Dopplergrams, and find that the filament’s counter-streaming motion is due to physical mass motion along fibrils, while the light bridge’s counter-streaming motion is due to oscillation in the direction along the line-of-sight. The oscillation power peaks around 4 minutes. However, the section of the light bridge next to the filament also contains a component of the extension of the filament in combination with the oscillation, indicating that some strands of the filament are extended to and rooted in that part of the light bridge.

Pad A treatability study long-range project plan

International Nuclear Information System (INIS)

Mousseau, J.D.

1991-06-01

This plan addresses the work to be accomplished by the Pad A Treatability Study Project. The purpose of this project is to investigate potential treatment and separation technologies, identify the best technologies, and to demonstrate by both lab- and pilot-scale demonstration, the most applicable remedial technologies for treating plutonium-contaminated salts at the Pad A site located at the Subsurface Disposal Area (SDA) at the Radioactive Waste Management Complex (RWMC) a the Idaho National Engineering Laboratory (INEL). The conduct of this project will be supported by other DOE laboratories, universities, and private industries, who will provide support for near-term demonstrations of treatment and separation technologies. The purpose of this long-range planning document is to present the detailed plan for the implementation of the Pad A Treatability Study Project

Pad-weighing test performed with standardized bladder volume

DEFF Research Database (Denmark)

Lose, G; Rosenkilde, P; Gammelgaard, J

1988-01-01

The result of the one-hour pad-weighing test proposed by the International Continence Society has been demonstrated to depend on the urine load during the test. To increase reproducibility of the pad-weighing test by minimizing the influence of variation in urine load the test was done with a sta...... to +/- 24 g between two tests. It is concluded that this setup (i.e., standardized bladder volume) of the one-hour pad-weighing test allows for a more reliable assessment of urinary incontinence for quantitative purposes....... with a standardized bladder volume (50% of the cystometric bladder capacity). Twenty-five female patients with stress or mixed incontinence underwent two separate tests. Test-retest results were highly correlated (r = 0.97, p less than 0.001). Nonetheless, analysis of test-retest differences revealed a variation up...

Evaluation of damping property of long-span prestressed concrete cable-stayed bridges; Chodai PC shachokyo no gensui tokusei ni kansuru kosatsu

Energy Technology Data Exchange (ETDEWEB)

Yamanobe, S.; Niihara, Y.; Minami, H.; Kono, T. [Kajima Corp., Tokyo (Japan)

1999-09-30

As to the dynamic design in the antiseismic design of PC cable-stayed bridges, evaluation of damping is important. Since it is difficult to evaluate damping property theoretically and analytically, a lot of studies have not been made about how to set up damping coefficients. In this study, using analytical models of existing long-span PC cable-stayed bridges, to clarify causes of damping of long-span PC cable-stayed bridge, the rate of strain energy in each member was examined. Equivalent damping coefficients of each member, effects of friction in movable bearing, and effects of basically radiational damping were studied. The correspondence with the results of the vibration experiments conventionally made were studied. (translated by NEDO)

Accurate micro Hall effect measurements on scribe line pads

DEFF Research Database (Denmark)

Østerberg, Frederik Westergaard; Petersen, Dirch Hjorth; Wang, Fei

2009-01-01

Hall mobility and sheet carrier density are important parameters to monitor in advanced semiconductor production. If micro Hall effect measurements are done on small pads in scribe lines, these parameters may be measured without using valuable test wafers. We report how Hall mobility can...... be extracted from micro four-point measurements performed on a rectangular pad. The dimension of the investigated pad is 400 × 430 ¿m2, and the probe pitches range from 20 ¿m to 50 ¿m. The Monte Carlo method is used to find the optimal way to perform the Hall measurement and extract Hall mobility most...

Journal bearing

Science.gov (United States)

Menke, John R.; Boeker, Gilbert F.

1976-05-11

1. An improved journal bearing comprising in combination a non-rotatable cylindrical bearing member having a first bearing surface, a rotatable cylindrical bearing member having a confronting second bearing surface having a plurality of bearing elements, a source of lubricant adjacent said bearing elements for supplying lubricant thereto, each bearing element consisting of a pair of elongated relatively shallowly depressed surfaces lying in a cylindrical surface co-axial with the non-depressed surface and diverging from one another in the direction of rotation and obliquely arranged with respect to the axis of rotation of said rotatable member to cause a flow of lubricant longitudinally along said depressed surfaces from their distal ends toward their proximal ends as said bearing members are rotated relative to one another, each depressed surface subtending a radial angle of less than 360.degree., and means for rotating said rotatable bearing member to cause the lubricant to flow across and along said depressed surfaces, the flow of lubricant being impeded by the non-depressed portions of said second bearing surface to cause an increase in the lubricant pressure.

The Akashi Kaikyo Bridge and the Storebælt Bridge

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

1999-01-01

With the completion of the Akashi Kaikyo Bridge and the Storebælt East Bridge the development of the suspension bridge technology in the 20th century has manifested itself in two impressive structures. With the present echnology may bridges of similar (and also more modest) dimensions...... will undoubtedly be built far into the next century. For bridges going beyond the spans of existing bridges it is, however, likely that new concepts will be developed....

Camshaft bearing arrangement

Energy Technology Data Exchange (ETDEWEB)

Aoi, K.; Ozawa, T.

1986-06-10

A bearing arrangement is described for the camshaft of an internal combustion engine or the like which camshaft is formed along its length in axial order with a first bearing surface, a first cam lobe, a second bearing surface, a second cam lobe, a third bearing surface, a third cam lobe and a fourth bearing surface, the improvement comprising first bearing means extending around substantially the full circumference of the first bearing surface and journaling the first bearing surface, second bearing means extending around substantially less than the circumference of the second bearing surface and journaling the second bearing surface, third bearing means extending around substantially less than the circumference of the third bearing surface and journaling the third bearing surface, and fourth bearing means extending around substantially the full circumference of the fourth bearing surface and journaling the first bearing surface.

Tentative provisions for seismic design of base isolated buildings in France

International Nuclear Information System (INIS)

Betbeder-Matibet, J.; Bisch, P.; Gantenbein, F.

1992-01-01

This paper presents Chapter 22 of the AFPS (French Earthquake Engineering Association) Recommendations, devoted to aseismic bearing pads. This chapter gives general rules applicable to any kind of pads, and specific rules for hooped elastomer pads. It contains specifications for general or detailed arrangements when aseismic bearing pads are used, calculation procedures (in particular, a simplified method), and a technical validation procedure for new designs of pads. (author)

Assessing the iPad as a tool for low-vision rehabilitation.

Science.gov (United States)

Mednick, Zale; Jaidka, Atul; Nesdole, Robert; Bona, Mark

2017-02-01

It has been demonstrated consistently that patients with poor vision have a reduced quality of life and functional status and higher rates of psychologic distress. This study aims to assess whether the iPad has potential as a visual aid in patients with low vision. Qualitative study with key-informant interviews. Patients who identified as having impaired vision were recruited from a low vision ophthalmology clinic. Patients participated in a 4-session iPad training course. The goal of the course was to teach patients with low vision how to operate an iPad, with a particular emphasis on how to optimize iPad settings and accessibility features in response to some of the challenges faced by patients with low vision. Three interviews were conducted with each participant: before the course, immediately after the course, and 3 months after the course. The purpose of the interviews was to gain an understanding of their experience with low vision and to assess if and how the iPad had influenced this experience. A grounded theory qualitative approach was used for analysis. Six patients took part in the study and were divided into 2 separate courses to minimize course size. Participants had favorable views regarding the course. Five of the 6 participants were using the iPad on a daily basis 3 months after the course. Thematic analysis revealed that use of the iPad led to both a heightened sense of independence and improved social connectivity. It is theorized that use of the iPad as a low-vision aid may enhance a patient's sense of self-worth. With proper training, the iPad has the potential to be a valuable tool for low-vision patients. Its features help patients to gain independence and to stay connected within their social circles. Further research with a larger patient population and quantifiable endpoints should focus on these themes. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Bridge Management Systems

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way....

Ultrasound appearance of knuckle pads

Energy Technology Data Exchange (ETDEWEB)

Lopez-Ben, R. [Univ. of Alabama, Birmingham (United States). Dept. of Diagnostic Radiology; Dehghanpisheh, K.; Chatham, W.W.; Alarcon, G.S. [Univ. of Alabama, Birmingham (United States). Dept. of Medicine; Lee, D.H.; Oakes, J. [Univ. of Alabama, Birmingham (United States). Dept. of Surgery

2006-11-15

We describe the ultrasound appearance of knuckle pads. Retrospective analysis of imaging in a series of five patients initially referred for evaluation of periarticular soft-tissue swelling of the hands involving the dorsum of the PIP and MP joints. Two patients had associated Dupuytren's contractures. Ultrasound and radiographs of the hands in all patients were reviewed and correlated with clinical history and physical exams. Radiographs in four patients demonstrated dorsal soft-tissue thickening. Ultrasound exams showed increased dorsal subcutaneous thickening, with either diffuse or focal hypoechoic areas corresponding to the areas of soft-tissue fullness identified on physical exam. No erosions or synovial proliferation were identified either by radiographs or ultrasound of the underlying joints. Knuckle pads can sometimes be difficult to distinguish from synovitis on physical examination. Musculoskeletal ultrasound can quickly identify these superficial lesions and exclude underlying synovial proliferation.

Rice pads. Devices to improve the effect of fat suppression of CHESS images

International Nuclear Information System (INIS)

Moriya, Susumu; Yokobayashi, Tsuneo; Miki, Yukio

2013-01-01

The chemical shift selective (CHESS) method is often used for fat suppression in magnetic resonance imaging. CHESS has several advantages, including versatility, quick imaging, and applicability to contrast examinations. One disadvantage of CHESS is the lingering fat signal generated as a result of nonuniformity of the static magnetic field. To overcome this drawback, some researchers have used pads made with polished rice (rice pads), a simple method in which rice pads are placed outside the area to be imaged. We describe ways to improve CHESS images, characteristics of the rice pad, its application to imaging, and methods of placing the pad. (author)

Biomechanical Comparison of Shorts With Different Pads

Science.gov (United States)

Marcolin, Giuseppe; Petrone, Nicola; Reggiani, Carlo; Panizzolo, Fausto A.; Paoli, Antonio

2015-01-01

Abstract An intensive use of the bicycle may increase the risk of erectile dysfunction and the compression of the perineal area has been showed to be a major mechanism leading to sexual alterations compromising the quality of life. Manufacturers claim that pads contribute to increase cyclists perineal protection ensuring a high level of comfort. To investigate the influence of various cycling pads with regard to perineal protection and level of comfort. Nine club road cyclists rode 20 min on a drum simulator, located at the Nutrition and Exercise Physiology Laboratory, at a constant speed and gear ratio wearing the shorts with 3 cycling pads of different design and thickness: basic (BAS), intermediate (INT), and endurance (END). Kinematics and pressure data were recorded at min 5, 15, and 20 of the test using a motion capture system and a pressure sensor mat. The variables of interest were: 3-dimensional pelvis excursions, peak pressure, mean pressure, and vertical force. The comfort level was assessed with a ranking order based on the subjects’ perception after the 20-min trials and measuring the vertical ground reaction force under the anterior wheel as well as the length of the center of pressure (COP) trajectory on the saddle. Results showed that the vertical force and the average value of mean pressure on the saddle significantly decreased during the 20-min period of testing for BAS and END. Mean peak pressure on the corresponding perineal cyclist area significantly increased only for BAS during the 20-min period. Interestingly objective comfort indexes measured did not match cyclists subjective comfort evaluation. The lower capacity of BAS to reduce the peak pressure on the corresponding perineal area after 20 min of testing, together with its positive comfort evaluation, suggest that a balance between protection and perceived comfort should be taken into account in the choice of the pad. Hence, the quantitative approach of objective comfort indexes

The use of Classical Rolling Pendulum Bearings (CRPB for vibration control of stay-cables

Directory of Open Access Journals (Sweden)

Papastergiou Georgia

2018-01-01

Full Text Available Cables are efficient structural elements that are used in cable-stayed bridges, suspension bridges and other cable structures. A significant problem which arose from the praxis is the cables’ rain-wind induced vibrations as these cables are subjected to environmental excitations. Rain-wind induced stay-cable vibrations may occur at different cable eigenfrequencies. Large amplitude Rain-Wind-Induced-Vibrations (RWIV of stay cables are a challenging problem in the design of cable-stayed bridges. Several methods, including aerodynamic or structural means, have been investigated in order to control the vibrations of bridge’s stay-cables. The present research focuses on the effectiveness of a movable anchorage system with a Classical Rolling Pendulum Bearing (CRPB device. An analytical model of cable-damper system is developed based on the taut string representation of the cable. The gathered integral-differential equations are solved through the use of the Lagrange transformation. . Finally, a case study with realistic geometrical parameters is also presented to establish the validity of the proposed system.

Bit-padding information guided channel hopping

KAUST Repository

Yang, Yuli

2011-02-01

In the context of multiple-input multiple-output (MIMO) communications, we propose a bit-padding information guided channel hopping (BP-IGCH) scheme which breaks the limitation that the number of transmit antennas has to be a power of two based on the IGCH concept. The proposed scheme prescribes different bit-lengths to be mapped onto the indices of the transmit antennas and then uses padding technique to avoid error propagation. Numerical results and comparisons, on both the capacity and the bit error rate performances, are provided and show the advantage of the proposed scheme. The BP-IGCH scheme not only offers lower complexity to realize the design flexibility, but also achieves better performance. © 2011 IEEE.

Development of radiation shielding materials and NBC pads for infantry combat vehicle and tank

International Nuclear Information System (INIS)

Pal, R.S.; Gautam, O.P.; Katiyar, Mohit; Tripathi, D.N.; Singh, R.K.

2008-01-01

Tanks have special lining materials inside, providing a certain degree of radiation protection for operation in nuclear scenario's. At present these special lining materials in the form of sheets are imported and are fitted into armoured vehicles. Three types of polymer compositions; PE(M)SE, PEC-ISE and PEC-IISE were formulated based on polymer matrix, specific fillers and anti-ageing additives. Prototype NBC pads based on polymer composition PEC-ISE was finalized for moulding of NBC pads for use in ICVs and composition PE(M)SE was finalized for T-90 tanks. The physico-mechanical properties for NBC pads have been evaluated. Radiography of test samples was conducted to ensure homogeneity of specific fillers in the polymer matrix. Radiation shielding factors against nuclear radiation sources ( 60 Co, I37 Cs and 252 Cf) were evaluated at DL Jodhpur and found to be better than imported Russian Pads designed for ICVs and T-90 Tanks. Drawings for twelve types of NBC pads for ICVs and one hundred eighteen types of pads for T-90 tank were generated with the help of design tool, Auto Desk Inventor-II and metallic moulds for moulding of NBC pads were fabricated. Prototype NBC pads were moulded through compression moulding process. Radiation protection factors of prototype NBC pads, after fitment in ICVs, were also evaluated against neutron and gamma (primary and secondary) radiation sources. Prototype NBC pads for ICVs have shown 20% improvement in overall protection level and NBC pads for T-90 tanks have been developed as per design requirements. Manufacturing facility for NBC shielding pads have been established in association with industries. (author)

iPads: Improving Numeracy Learning in the Early Years

Science.gov (United States)

Spencer, Peta

2013-01-01

The concept of mobile technologies is now an emergency theme in educational research, yet the playing of these edutainment applications and their impact on early childhood learning needs to be fully explored. This study highlights current research and explores how iPads improve student learning. It also examines how the introduction of iPads,…

iPad Use and Student Engagement in the Classroom

Science.gov (United States)

Mango, Oraib

2015-01-01

iPads and handheld digital devices have been securing their place in educational institutions surrounded by debates between advocates and skeptics. In light of not enough evidence supporting the use of iPads in education, this study examined the ways that college students in two foreign language classrooms perceived the influence of the use of…

ImagePAD, a novel counting application for the Apple iPad, used to quantify axons in the mouse optic nerve.

Science.gov (United States)

Templeton, Justin P; Struebing, Felix L; Lemmon, Andrew; Geisert, Eldon E

2014-11-01

The present article introduces a new and easy to use counting application for the Apple iPad. The application "ImagePAD" takes advantage of the advanced user interface features offered by the Apple iOS platform, simplifying the rather tedious task of quantifying features in anatomical studies. For example, the image under analysis can be easily panned and zoomed using iOS-supported multi-touch gestures without losing the spatial context of the counting task, which is extremely important for ensuring count accuracy. This application allows one to quantify up to 5 different types of objects in a single field and output the data in a tab-delimited format for subsequent analysis. We describe two examples of the use of the application: quantifying axons in the optic nerve of the C57BL/6J mouse and determining the percentage of cells labeled with NeuN or ChAT in the retinal ganglion cell layer. For the optic nerve, contiguous images at 60× magnification were taken and transferred onto an Apple iPad. Axons were counted by tapping on the touch-sensitive screen using ImagePAD. Nine optic nerves were sampled and the number of axons in the nerves ranged from 38,872 axons to 50,196 axons with an average of 44,846 axons per nerve (SD = 3980 axons). Copyright © 2014 Elsevier Ltd. All rights reserved.

iPhone and iPad apps for absolute beginners

CERN Document Server

Lewis, Rory

2013-01-01

So how do you build an application for the iPhone and iPad? Don't you need to spend years learning complicated programming languages? What about Objective-C and Cocoa touch? The answer is that you don't need to know any of those things! Anybody can start building simple apps for the iPhone and iPad, and this book will show you how. This update of an Apress bestseller walks you through creating your first app, using plain English and practical examples using the iOS 6 software development platform and more. It cuts through the fog of jargon and misinformation that surrounds iPhone and iPad app

iBooks and ePeriodicals on the iPad

CERN Document Server

Biersdorfer, J

2010-01-01

This Mini Missing Manual takes you down the virtual rows of Apple's iBookstore, to help you find, buy, and download books and subscribe to magazine and newspapers on your iPad. You'll learn now to navigate your books and periodicals and sync them back to iTunes to swap them on and off your iPad to free up storage space. In addition, you'll find out where to get free books in the iBookstore, and where you can shop for iPad-compatible books, both free and for-pay, outside of Apple's domain. Finally, you'll learn the fine art of eBook navigation, including how to change a book's font and font

Pad-mode-induced instantaneous mode instability for simple models of brake systems

Science.gov (United States)

Oberst, S.; Lai, J. C. S.

2015-10-01

Automotive disc brake squeal is fugitive, transient and remains difficult to predict. In particular, instantaneous mode squeal observed experimentally does not seem to be associated with mode coupling and its mechanism is not clear. The effects of contact pressures, friction coefficients as well as material properties (pressure and temperature dependency and anisotropy) for brake squeal propensity have not been systematically explored. By analysing a finite element model of an isotropic pad sliding on a plate similar to that of a previously reported experimental study, pad modes have been identified and found to be stable using conventional complex eigenvalue analysis. However, by subjecting the model to contact pressure harmonic excitation for a range of pressures and friction coefficients, a forced response analysis reveals that the dissipated energy for pad modes is negative and becomes more negative with increasing contact pressures and friction coefficients, indicating the potential for instabilities. The frequency of the pad mode in the sliding direction is within the range of squeal frequencies observed experimentally. Nonlinear time series analysis of the vibration velocity also confirms the evolution of instabilities induced by pad modes as the friction coefficient increases. By extending this analysis to a more realistic but simple brake model in the form of a pad-on-disc system, in-plane pad-modes, which a complex eigenvalue analysis predicts to be stable, have also been identified by negative dissipated energy for both isotropic and anisotropic pad material properties. The influence of contact pressures on potential instabilities has been found to be more dominant than changes in material properties owing to changes in pressure or temperature. Results here suggest that instantaneous mode squeal is likely caused by in-plane pad-mode instabilities.

Metacarpophalangeal joint synovial pad fibrotic proliferation in 63 horses

International Nuclear Information System (INIS)

Dabareiner, R.M.; White, N.A.; Sullins, K.E.

1996-01-01

Medical records, radiographs, and sonograms of 63 horses with metacarpophalangeal joint synovial pad proliferation were examined retrospectively. AR horses had lameness, joint effusion, or both signs associated with one or both metacarpophalangeal joints. Bony remodeling and concavity of the distodorsal aspect of the third metacarpal bone (Mc3) just proximal to the metacarpal condyles was identified by radiography in 71 joints (93%); 24 joints (32%) had radiographic evidence of a chip fracture located at the proximal dorsal aspect of the proximal phalanx. Fifty-four joints (71%) were examined by ultrasound. The mean +- SD sagittal thickness of the synovial pad was 11.3 +- 2.8 mm. Seventy-nine percent of the horses had single joint involvement with equal distribution between the right and left forelimbs. Sixty-eight joints in 55 horses were treated by arthroscopic surgery. Sixty joints (88%) had debridement of chondral or osteochondral fragmentation from the dorsal surface of Mc3 beneath the synovial pad and 30 joints (44%) had a bone chip fracture removed from the medial or lateral proximal dorsal eminence of the proximal phalanx. Complete or partial excision of both medial and lateral synovial pads was completed in 42 joints. Only the medial synovial pad was excised or trimmed in 21 joints, and 5 joints had only the lateral pad removed. Eight joints in eight horses were treated by stall rest, administration of intra-articular medication and systemic nonsteroidal anti-inflammatory drugs. Follow-up information was obtained for 50 horses treated surgically and for eight horses treated medically. Forty-three (86%) that had surgery returned to racing; 34 (68%) raced at an equivalent or better level than before surgery. Three (38%) of the medically treated horses returned to racing; only one horse raced better than the preinjury level. Horses that returned to racing at a similar or equal level of performance were significantly younger in age than horses returning at a

Railroad Bridges

Data.gov (United States)

Department of Homeland Security — Bridges-Rail in the United States According to The National Bridge Inspection Standards published in the Code of Federal Regulations (23 CFR 650.3), a bridge isA...

Adhesive foot pads: an adaptation to climbing? An ecological survey in hunting spiders.

Science.gov (United States)

Wolff, Jonas O; Gorb, Stanislav N

2015-02-01

Hairy pads relying on dry adhesion are fascinating structures that convergently evolved among spiders and lizards. Numerous studies underline the functional aspects leading to their strong adhesion to smooth surfaces, but rarely has their role been studied in the context of natural habitats and surfaces that animals are faced with. In hunting spiders, the hairy foot pads (claw tufts) underneath the paired claws are assumed to be an adaptation to a climbing lifestyle, particularly on smooth plant surfaces. However, surfaces that are too smooth for claws to generate a sufficient grip are rather rare in natural habitats and above-ground habitats are occupied by hunting spiders both with and without claw tufts. In this study we estimated the proportion of claw tuft-bearing hunting spiders (ct+ ratio) among microhabitat-specific assemblages by conducting both a field study and a meta-analysis approach. The effect of surface characteristics, structure fragmentation and altitude of the microhabitat niche on the ct+ ratio was analyzed. We hypothesized that the ct+ ratio will be higher in (i) hunting spider assemblages obtained from microhabitats above the ground than from those at the ground and (ii) in hunting spider assemblages obtained from microhabitats with smoother surfaces (tree foliage) than those with rougher surfaces (barks, stones), and lower in (iii) hunting spider assemblages obtained from microhabitats with more fragmented structures (small leaves) than in those with comparable but less fragmented structures (large leaves). We found the ct+ ratio to be significantly affected by the microhabitat's distance from the ground, whereas surface characteristics and fragmentation of the substrates were of minor importance. This suggests that claw tufts are highly beneficial when the microhabitat's height exceeds a value where the additional pad-related costs are exceeded by the costs of dropping. We assume the benefit to be mainly due to gaining a high safety factor

Study on the Mechanical Properties of Stay Cable HDPE Sheathing Fatigue in Dynamic Bridge Environments

Directory of Open Access Journals (Sweden)

Danhui Dan

2015-08-01

Full Text Available As the main force-bearing component of a cable-stayed bridge, a durable stay cable is paramount to the safety and durability of the entire bridge. High-density polyethylene (HDPE sheathing is the main protective component of a stay cable and is the key to insuring cable durability. To address the issue of HDPE sheathing fracture on service, strain level data for in-service, HDPE bridge cable sheathing was used in this study as the basis for HDPE material aging and fatigue testing. A fatigue yield phenomenon with a yield platform on the hysteresis curve of the fatigue cycles is observed by the fatigue test. The parameters to describe this phenomenon are proposed and defined in this paper. A preliminary examination of the relationship between these parameters and the factors, such as the number of cycles, the strain amplitude, and strain rate, are presented. Based on the results obtained, it is suggested that the condition of fatigue yield of HDPE sheathing be defined as the fatigue durability limit state for the purposes of durability design, assessment, and protection of cable-stayed bridges.

A novel nonlinear nano-scale wear law for metallic brake pads.

Science.gov (United States)

Patil, Sandeep P; Chilakamarri, Sri Harsha; Markert, Bernd

2018-05-03

In the present work, molecular dynamics simulations were carried out to investigate the temperature distribution as well as the fundamental friction characteristics such as the coefficient of friction and wear in a disc-pad braking system. A wide range of constant velocity loadings was applied on metallic brake pads made of aluminium, copper and iron with different rotating speeds of a diamond-like carbon brake disc. The average temperature of Newtonian atoms and the coefficient of friction of the brake pad were investigated. The resulting relationship of the average temperature with the speed of the disc as well as the applied loading velocity can be described by power laws. The quantitative description of the volume lost from the brake pads was investigated, and it was found that the volume lost increases linearly with the sliding distance. Our results show that Archard's linear wear law is not applicable to a wide range of normal loads, e.g., in cases of low normal load where the wear rate was increased considerably and in cases of high load where there was a possibility of severe wear. In this work, a new formula for the brake pad wear in a disc brake assembly is proposed, which displays a power law relationship between the lost volume of the metallic brake pads per unit sliding distance and the applied normal load with an exponent of 0.62 ± 0.02. This work provides new insights into the fundamental understanding of the wear mechanism at the nano-scale leading to a new bottom-up wear law for metallic brake pads.

IntelligentPad for exchanging and reusing nuclear reaction data information as shared resources

International Nuclear Information System (INIS)

Chiba, Masaki

1996-01-01

As an application of the IntelligentPad system, the NRDF database system is redesigned and developed. In the system, every component of the user interface is represented by reactive media objects called Pad. The exploitation of the IntelligentPad architecture in developing the system enhances the usability and reusability of the tools developed. Several pads specially designed for the NRDF database system are shown together with the examples of how to use them. (author)

Implementation of Bridge Management System on Interurban Bridge in Maluku Province

Directory of Open Access Journals (Sweden)

Erwin Marasabessy

2015-05-01

Full Text Available Bridges as transport infrastructures play a vital role in smoothing traffic flows. The success of a bridge in playing its role and serving its function depends on its management. The Directorate General of Highways of the Ministry of Public Work has used a system to manage bridges known as the Bridge Management System (BMS. The system allows a systematic plan and provides a uniform procedure for all bridge operation activities on the national and provincial level. Data from Implementation Agency of National Inter-Urban Roads of Area IX, Northern Maluku in 2011 indicates that the total length of national roads in Maluku Province is 15,238.01 M, with a total of 562 bridges. In Ambon Island, especially, there are 52 bridges totaling 1,176.25 m in length. The study was conducted at several inter-urban bridges in Maluku Province of Ambon Island: Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari and Wai Tua bridges. Assessment of bridge structure conditions was conducted visually to determine the conditions of the existing bridges comprehensively by referring to the Bridge Management System (BMS complemented with a computer-based Bridge Management Information System (BMIS. Condition scores for the five bridges—Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua, according to Bridge Management System, are 2, 1, 2, 1, and 2 respectively. The scores of the five bridges indicate that their physical condition can be categorized as good or with minor defects. Based on technical screening, the proposed treatment for Wai Batu Merah, Wai Ruhu, Wai Lawa, dan Wai Tua bridges is the rehabilitation of their sub-elements. As for the Wai Yari Bridge, the treatment will be maintained regularly. The defect repair costs are IDR 149,138,238.00, IDR 81,048,000.00, IDR 174,579,106.10, IDR 79,233,324.01 and IDR 238,323,258.60 for Wai Batu, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua Bridges, respectively.

Chemical mechanical planarization of amorphous Ge2Sb2Te5 with a soft pad

International Nuclear Information System (INIS)

He Aodong; Liu Bo; Song Zhitang; Lü Yegang; Li Juntao; Liu Weili; Feng Songlin; Wu Guanping

2013-01-01

Chemical mechanical planarization (CMP) of amorphous Ge 2 Sb 2 Te 5 (a-GST) is investigated using two typical soft pads (politex REG and AT) in acidic slurry. After CMP, it is found that the removal rate (RR) of a-GST increases with an increase of runs number for both pads. However, it achieves the higher RR and better surface quality of a-GST for an AT pad. The in-situ sheet resistance (R s ) measure shows the higher R s of a-GST polishing can be gained after CMP using both pads and the high R s is beneficial to lower the reset current for the PCM cells. In order to find the root cause of the different RR of a-GST polishing with different pads, the surface morphology and characteristics of both new and used pads are analyzed, it shows that the AT pad has smaller porosity size and more pore counts than that of the REG pad, and thus the AT pad can transport more fresh slurry to the reaction interface between the pad and a-GST, which results in the high RR of a-GST due to enhanced chemical reaction. (semiconductor technology)

Ultimate strength analysis of long-span cable-stayed bridges; Chodai chachokyo no shukyoku kyodo kaiseki to kyodo ni kansuru ichikosatsu

Energy Technology Data Exchange (ETDEWEB)

Xie, X.; Yamaguchi, H. [Saitama Univ., Urawa (Japan)] Nagai, M. [Nagaoka Technical Coll., Niigata (Japan)

1998-07-21

Recently, span of cable-stayed bridges has been getting loner and longer, present situation is that cable-stayed bridges with span 600 to 800m class have been built inside and outside the country, and accurate determination of its ultimate strength has been an important problem statistically. However, concrete design method for evaluating load bearing stress of long-span cable-stayed bridge. Particularly of the main beam whose axial stress is dominating, has not been established so far. As for cable-stayed bridge, even for long-span, effect of plasticization of cross section on ultimate strength is severe because there is little effect of geometric nonlinearity and it is thought that accurate evaluation of ultimate strength only by elastic finite potential analysis is difficult. Accordingly, it is necessary to study the behavior by using combined nonlinear analysis considering the nonlinearity of the material in order to evaluate the safety and economy to long-span cable-stayed bridge. In this report, 3 dimensional analysis method was formularized taking into account the combine nonlinearity of multi-box girder and analysis program of ultimate strength behavior of long-span cable-stayed bridge was developed. 19 refs., 17 figs., 2 tabs.

Fast micro Hall effect measurements on small pads

DEFF Research Database (Denmark)

Østerberg, Frederik Westergaard; Petersen, Dirch Hjorth; Nielsen, Peter F.

2011-01-01

Sheet resistance, carrier mobility, and sheet carrier density are important parameters in semiconductor production, and it is therefore important to be able to rapidly and accurately measure these parameters even on small samples or pads. The interpretation of four-point probe measurements on small...... pads is non-trivial. In this paper we discuss how conformal mapping can be used to evaluate theoretically expected measurement values on small pads. Theoretical values calculated from analytical mappings of simple geometries are compared to the values found from the numerical conformal mapping...... of a square onto the infinite half-plane, where well-established solutions are known. Hall effect measurements are performed to show, experimentally, that it is possible to measure Hall mobility in less than one minute on squares as small as 7070 lm2 with a deviation of 66.5% on a 1r level from accurate...

Exposure-rate calibration using large-area calibration pads

International Nuclear Information System (INIS)

Novak, E.F.

1988-09-01

The US Department of Energy (DOE) Office of Remedial Action and Waste Technology established the Technical Measurements Center (TMC) at the DOE Grand Junction Projects Office (GJPO) in Grand Junction, Colorado, to standardize, calibrate, and compare measurements made in support of DOE remedial action programs. A set of large-area, radioelement-enriched concrete pads was constructed by the DOE in 1978 at the Walker Field Airport in Grand Junction for use as calibration standards for airborne gamma-ray spectrometer systems. The use of these pads was investigated by the TMC as potential calibration standards for portable scintillometers employed in measuring gamma-ray exposure rates at Uranium Mill Tailings Remedial Action (UMTRA) project sites. Data acquired on the pads using a pressurized ionization chamber (PIC) and three scintillometers are presented as an illustration of an instrumental calibration. Conclusions and recommended calibration procedures are discussed, based on the results of these data

Internal strain estimation for quantification of human heel pad elastic modulus: A phantom study

DEFF Research Database (Denmark)

Holst, Karen; Liebgott, Hervé; Wilhjelm, Jens E.

2013-01-01

Shock absorption is the most important function of the human heel pad. However, changes in heel pad elasticity, as seen in e.g. long-distance runners, diabetes patients, and victims of Falanga torture are affecting this function, often in a painful manner. Assessment of heel pad elasticity...... is usually based on one or a few strain measurements obtained by an external load-deformation system. The aim of this study was to develop a technique for quantitative measurements of heel pad elastic modulus based on several internal strain measures from within the heel pad by use of ultrasound images. Nine...... heel phantoms were manufactured featuring a combination of three heel pad stiffnesses and three heel pad thicknesses to model the normal human variation. Each phantom was tested in an indentation system comprising a 7MHz linear array ultrasound transducer, working as the indentor, and a connected load...

iPad in the Enterprise Developing and Deploying Business Applications

CERN Document Server

Clevenger, Nathan

2011-01-01

Discover how to plan, design, develop, and deploy iPad apps for the enterprise Having taken the enterprise by storm, iPads are now in the hands of workers in virtually every level of companies in almost every industry. But using iPad apps in the enterprise is more complex than simply clicking an icon from the App Store. It presents unique challenges around software development, system integration, information security, application deployment, and device management. That's where this book comes in. iPhone Life Enterprise Editor and veteran mobile consultant Nathan Clevenger presents a guide for

Mechanical behaviour of the heel pad: experimental and numerical approach

DEFF Research Database (Denmark)

Matteoli, Sara; Fontanella, C. G.; Virga, A.

The aim of the present work was to investigate the stress relaxation phenomena of the heel pad region under different loading conditions. A 31-year-old healthy female was enrolled in this study and her left foot underwent both MRI and experimental compression tests. Experimental results were...... compared with those obtained from finite element analysis performed on numerical 3D subject-specific heel pad model built on the basis of MRI. The calcaneal fat pad tissue was described with a visco-hyperelastic model, while a fiber-reinforced hyperelastic model was formulated for the skin. The reliability...

Arachnids secrete a fluid over their adhesive pads.

Directory of Open Access Journals (Sweden)

Anne M Peattie

Full Text Available BACKGROUND: Many arachnids possess adhesive pads on their feet that help them climb smooth surfaces and capture prey. Spider and gecko adhesives have converged on a branched, hairy structure, which theoretically allows them to adhere solely by dry (solid-solid intermolecular interactions. Indeed, the consensus in the literature is that spiders and their smooth-padded relatives, the solifugids, adhere without the aid of a secretion. METHODOLOGY AND PRINCIPAL FINDINGS: We investigated the adhesive contact zone of living spiders, solifugids and mites using interference reflection microscopy, which allows the detection of thin liquid films. Like insects, all the arachnids we studied left behind hydrophobic fluid footprints on glass (mean refractive index: 1.48-1.50; contact angle: 3.7-11.2°. Fluid was not always secreted continuously, suggesting that pads can function in both wet and dry modes. We measured the attachment forces of single adhesive setae from tarantulas (Grammostola rosea by attaching them to a bending beam with a known spring constant and filming the resulting deflection. Individual spider setae showed a lower static friction at rest (26%±2.8 SE of the peak friction than single gecko setae (Thecadactylus rapicauda; 96%±1.7 SE. This may be explained by the fact that spider setae continued to release fluid after isolation from the animal, lubricating the contact zone. SIGNIFICANCE: This finding implies that tarsal secretions occur within all major groups of terrestrial arthropods with adhesive pads. The presence of liquid in an adhesive contact zone has important consequences for attachment performance, improving adhesion to rough surfaces and introducing rate-dependent effects. Our results leave geckos and anoles as the only known representatives of truly dry adhesive pads in nature. Engineers seeking biological inspiration for synthetic adhesives should consider whether model species with fluid secretions are appropriate to their

Friction and Braking Application of Unhazardous Palm Slag Brake Pad Composite

Science.gov (United States)

Khoni, Norizzahthul Ainaa Abdul; Ruzaidi Ghazali, Che Mohd; Bakri Abdullah, Mohd Mustafa Al

2018-03-01

This paper reveals new alternative friction materials for brake pads. Palm slag was studied as new friction materials in brake pads but its much harder made it difficult to be applied. As a way to reduce the hardness, tire dust was including as purpose on stabilizing the hardness of brake pads. The palm slag was sieves to get desired size that is 150 μm, 300 μm and 600 μm. The percentage weight of materials used are 20% graphite, 20% aluminium oxide, 20% steel fiber, 20% polyester resin and another 40% are varied between tire dust and palm slag. All of materials were blend and compress by using hot pressed machine. The composites properties that were examined are density, porosity, hardness, compressive strength, microstructure analysis and wear rate. The composition of 30% palm slag, 10% tire dust and larger size of filler give better result of mechanical properties and less wear rate of brake pads composites. Then, palm slag can be used in producing of non asbestos brake pads.

Long-term bridge performance high priority bridge performance issues.

Science.gov (United States)

2014-10-01

Bridge performance is a multifaceted issue involving performance of materials and protective systems, : performance of individual components of the bridge, and performance of the structural system as a whole. The : Long-Term Bridge Performance (LTBP)...

Implementation Factors and Faculty Perceptions of Electronic Textbooks on the iPad

Science.gov (United States)

Rogers-Estable, Michelle Dawn

2018-01-01

A federally managed university in the United Arab Emirates implemented a one-to-one iPad program. In an effort to increase access to interactive digital learning resources on the iPads, they next transitioned from paperbased textbooks (pTexts) to electronic textbooks (eTexts) on the iPad for all course delivery formats. The goal of this study was…

Een jaar later, onderzoek naar de implementatie van de iPad bij het Leeuwarder Lyceum : Een vervolgonderzoek naar het iPad-gebruik onder leerlingen en leraren van het Leeuwarder Lyceum

NARCIS (Netherlands)

Stephanie Nijssen; Klaas Jan Huizing

2013-01-01

In september 2012 is de iPad geïmplementeerd in het onderwijs van het Leeuwarder Lyceum. Sowijs onderzocht tijdens de implementatie welke verwachtingen leerlingen en leraren hadden van de iPad. Nu, een jaar later, hebben we opnieuw onderzoek gedaan onder leerlingen en leraren naar het iPad-gebruik.

Quantum One-Time Pad in the Presence of an Eavesdropper

Science.gov (United States)

Brandão, Fernando G. S. L.; Oppenheim, Jonathan

2012-01-01

A classical one-time pad allows two parties to send private messages over a public classical channel—an eavesdropper who intercepts the communication learns nothing about the message. A quantum one-time pad is a shared quantum state which allows two parties to send private messages or private quantum states over a public quantum channel. If the eavesdropper intercepts the quantum communication she learns nothing about the message. In the classical case, a one-time pad can be created using shared and partially private correlations. Here we consider the quantum case in the presence of an eavesdropper, and find the single-letter formula for the rate at which the two parties can send messages using a general quantum state as a quantum one-time pad. Surprisingly, the formula coincides with the distillable entanglement assisted by a symmetric channel, an important quantity in quantum information theory, but which lacked a clear operational meaning.

Contact statuses between functionally graded brake disk and pure pad disk

International Nuclear Information System (INIS)

Shahzamanian, M.M.; Sahari, B.B.; Bayat, M.; Mustapha, F.; Ismarrubie, Z.N.; Shahrjerdi, A.

2009-01-01

Full text: The contact statuses between functionally graded (FG) brake disks and pure pad disk are investigated by using finite element method (FEM). Two types of variation is considered for FG brake disk, the variation of materials are considered change in radial and thickness direction of disk. The material properties of these two types of FG brake disks are assumed to be represented by power-law distributions in the radius and thickness direction. The results are obtained and then compared. For the radial FG brake disk, the inner and outer surfaces are considered metal and ceramic respectively, and friction coefficient between metal surface and ceramic surface of FG brake dick with pad are considered 1.4 and 0.75 respectively. For the thickness FG brake disk the contact surface with pure pad brake disk is ceramic and the free surface is metal and friction coefficient between ceramic (contact) surface and pure pad brake disk is considered 0.75. In both types of FG brake disks the Coulomb contact friction is applied. Mechanical response of FG brake disks are compared and verified with the known results in the literatures. Three types of contact statuses are introduced as Sticking, Contact and Near Contact. The contact status between pad and disk for different values for pad thickness, grading index,n , and percentage of friction coefficient (λ) is shown. It can be seen that for all values of percentage of friction coefficient,λ , and grading indices, n, by increasing the thickness of pad cause the contact status changes from sticking to contact and then to near contact. (author)

47 CFR 80.163 - Operator requirements of the Bridge-to-Bridge Act.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operator requirements of the Bridge-to-Bridge... Requirements § 80.163 Operator requirements of the Bridge-to-Bridge Act. Each ship subject to the Bridge-to-Bridge Act must have on board a radio operator who holds a restricted radiotelephone operator permit or...

The effects of porosity in friction performance of brake pad using waste tire dust

Directory of Open Access Journals (Sweden)

İbrahim Mutlu

2015-10-01

Full Text Available Abstract This research is focused on the effect of porosity on the friction-wear properties of automotive brake pads. Waste Tire Dust (WTD was used as a new friction material in brake pads. Newly formulated brake pad materials with five different components have been produced by conventional techniques. In the experimental studies, the change of the friction coefficient, the temperature of the friction surface, the specific wear rate, and the hardness, density and porosity were measured. In addition, the micro-structural characterizations of brake pads are determined using Scanning Electron Microscopy (SEM. The mean coefficient of friction, porosity and specific wear are increased due to a WTD rate increases, on the other hand, hardness and density are decreased. As a result, WTD can be considered as an alternative to revalorize this kind of waste products in the brake pads and the amount of porosity of the brake pad affected the friction coefficient and wear behavior of the pad.

Dew point effect of cooled hydrogel pads on human stratum corneum biosurface.

Science.gov (United States)

Xhauflaire-Uhoda, Emmanuelle; Paquet, Philippe; Piérard, Gérald E

2008-01-01

Cooled hydrogel pads are used to prevent overheating effects of laser therapy. They do not induce cold injuries to the skin, but their more subtle physiological effects have not been thoroughly studied. To describe the changes in transepidermal water loss and electrometric properties of the skin surface following application of cooled hydrogel pads. Measurements were performed on normal forearm skin of 27 healthy volunteers and on freshly excised skin from abdominoplasty. LaserAid hydrogel pads cooled to 4 degrees C were placed for 15 min on the forearm skin. Measurements of transepidermal water loss (TEWL) and electrometric properties (Corneometer, Nova DPM 900) were performed before application and after removal of the cooled pads. A consistent increase in corneometer units, dermal phase meter (DPM) values and TEWL were recorded at removal of the cooled hydrogel pads. Both the in vivo and in vitro assessments brought similar information. The similar changes disclosed in vitro and in vivo suggest that a common physical process is operating in these conditions. The observed phenomenon is opposite to the predicted events given by the Arrhenius law probably because of the combination of cooling and occlusion by the pads. A dew point effect (air temperature at which relative humidity is maximal) is likely involved in the moisture content of the stratum corneum. Thus, the biological impact of using cooling hydrogel pads during laser therapy is different from the effect of a cryogenic spray cooling procedure. The better preservation of the water balance in the stratum corneum by the cooled hydrogel pads could have a beneficial esthetic effect on laser treated areas. (c) 2008 S. Karger AG, Basel.

The floating cardiac fat pad-sign of occult pneumothorax.

Science.gov (United States)

Kaufman, Claire; Bokhari, S A Jamal

2016-08-01

Pneumothoraces are a possible sequela of chest trauma with potential morbidity and mortality if not recognized and treated promptly. A portable supine chest radiograph is frequently the first radiologic study performed in the setting of trauma. While large pneumothoraces can be readily recognized on these radiographs, smaller pneumothoraces are missed in up to 15 % of trauma patients. There are many radiographic signs of occult pneumothoraces, and we are presenting a new radiographic sign of occult pneumothorax. The floating cardiac fat pad sign occurs when pleural air collects anteriorly and superiorly in the most non-dependent portion of the chest lifting the pericardial fat pad off the diaphragm. Lung markings are still seen surrounding the pericardial fat pad due to the inflated lower lobe of the lung resting dependently. Rapid and accurate identification of pneumothoraces is critical but often difficult on chest radiographs. Although there are many existing radiographic signs for identification of pneumothorax, prospective identification of small pneumothoraces is still relatively poor. Here, we describe an additional sign which aides in the detection of pneumothoraces, the floating cardiac fat pad. When present, this should prompt further evaluation with chest CT or upright chest radiograph.

Bridge health monitoring metrics : updating the bridge deficiency algorithm.

Science.gov (United States)

2009-10-01

As part of its bridge management system, the Alabama Department of Transportation (ALDOT) must decide how best to spend its bridge replacement funds. In making these decisions, ALDOT managers currently use a deficiency algorithm to rank bridges that ...

Impact of the rail-pad multi-discrete model upon the prediction of the rail response

Science.gov (United States)

Mazilu, T.; Leu, M.

2017-08-01

Wheel/rail vibration has many technical effects such as wear of the rolling surfaces, rolling noise, settlement of the ballast and subgrade etc. This vibration is depending on the rail pad characteristic and subsequently, it is important to have an accurate overview on the relation between the rail pad characteristic and the level of the wheel/rail vibration. To this end, much theoretical and experimental research has been developed in the past, and for the theoretical approach the track model, in general, and, particularly, the rail pad model is of crucial importance. Usually, the rail pad model is discrete model one, neglecting the length of the rail pad. This fact is questionable because the sleepers span is only 4 times the rail pad length. Using the rail pad discrete model, the rail response is overestimated when the frequency of the excitation equals the pinned-pinned resonance frequency. In this paper, a multi-discrete model for the rail pad, consisting in many Kelvin-Voigt parallel systems, is inserted into an analytical model of the track. The track model is reduced to a rail taken as infinite Timoshenko beam, discretely supported via rail pad, sleeper and ballast. The influence of the number of Kelvin-Voigt systems of the rail pad model on the rail response is analysed.

Effect of Gender on Mechanical Properties of the Plantar Fascia and Heel Fat Pad.

Science.gov (United States)

Taş, Serkan

2017-10-01

The purpose of the study was to investigate the plantar fascia and heel fat pad stiffness and thickness parameters in females and compare these values with those of males. This study was carried out in 60 healthy sedentary participants (30 female, 30 male) between the ages of 19 and 50 years. Shear wave velocity (SWV) and thickness of the plantar fascia and heel fat pad were measured with an ultrasonography device. Males had a higher plantar fascia ( P = .037) and heel fat pad ( P = .001) thickness compared with females, but SWV of the plantar fascia ( P = .673), heel fat pad microchamber layer ( P = .240), and heel fat pad macrochamber layer ( P = .636) were similar in both groups. Body mass had a strong correlation with the plantar fascia ( r = 0.64, P plantar fascia ( r = 0.44, P Plantar fascia and heel fat pad stiffness were similar in both genders; however, females had a lower plantar fascia and heel fat pad thickness compared with males. Correlation analysis results suggest that higher plantar fascia and heel fat pad thickness in males may be related to higher body mass and height. Level III, Retrospective comparative study.

Effect of Piers Shape on the Dynamic Structural Responses of Prestressed Concrete Bridge: Part II

Directory of Open Access Journals (Sweden)

Ali Fadhil Naser

2016-03-01

Full Text Available Pier of bridge is usually used as a general term for any type of substructure located between horizontal spans and foundations. Piers give vertical supports for spans at intermediate points and perform two main functions. The objective of this study is to inspect the effect of piers shape on the dynamic structural performance by adopting theoretical dynamic analysis. The results of dynamic analysis of 25 bridges models show that the maximum value of natural frequency is equal to 5.64Hz in two circles piers bridge model. Therefore, this type of model has good stiffness and bearing capacity. The two square piers model, the one circle pier model, and the two circles piers model appear good stiffness because of the natural frequencies (5.30Hz, 5.52Hz, and 5.64Hz are more than the maximum forced frequencies (4.52Hz, 5.45Hz, and 4.52Hz respectively. According to the comparison between all models results, the two circles piers model has the higher stiffness because of this model has the maximum value of natural frequency (5.64Hz and it is more than all forced vibration frequencies of all others models. Therefore, this study recommends that using the bridge model of two circles piers in the bridges construction that consists of three spans (30m+40m+30m with section of box girder.

Effect of Piers Shape on the Dynamic Structural Responses of Prestressed Concrete Bridge: Part II

Directory of Open Access Journals (Sweden)

Ali Fadhil Naser

2016-12-01

Full Text Available Pier of bridge is usually used as a general term for any type of substructure located between horizontal spans and foundations. Piers give vertical supports for spans at intermediate points and perform two main functions. The objective of this study is to inspect the effect of piers shape on the dynamic structural performance by adopting theoretical dynamic analysis. The results of dynamic analysis of 25 bridges models show that the maximum value of natural frequency is equal to 5.64Hz in two circles piers bridge model. Therefore, this type of model has good stiffness and bearing capacity. The two square piers model, the one circle pier model, and the two circles piers model appear good stiffness because of the natural frequencies (5.30Hz, 5.52Hz, and 5.64Hz are more than the maximum forced frequencies (4.52Hz, 5.45Hz, and 4.52Hz respectively. According to the comparison between all models results, the two circles piers model has the higher stiffness because of this model has the maximum value of natural frequency (5.64Hz and it is more than all forced vibration frequencies of all others models. Therefore, this study recommends that using the bridge model of two circles piers in the bridges construction that consists of three spans (30m+40m+30m with section of box girder.

How does the presence of excreta affect the behavior of laying hens on scratch pads?

Science.gov (United States)

Pokharel, B B; Boecker, I; Kwon, I Y; Jeyachanthiran, L; McBride, P; Harlander-Matauschek, A

2018-03-01

Enriched cages for laying hens provide scratch pads for foraging on the wire mesh floors. Apart from foraging on scratch pads, hens also defecate on these pads, causing them to become soiled with excreta. This study was conducted to determine the relative preference of laying hens for foraging on clean (C) scratch pads or scratch pads soiled with excreta (E), and to study the behaviors performed by hens on such pads. A total of 288 laying hens was housed in 16 enriched cages (18 hens/cage), each divided into 2 compartments. On a daily basis, half of the scratch pads (one in each compartment) were removed and cleaned, while the other half were cleaned and then covered with 550 g (0.35 g/cm2) of conspecific excreta. The C and E scratch pads were then put back into the cages in a systematic order to avoid side bias. Feed was delivered automatically onto the scratch pads as a litter substrate. The frequency of visits and the total time spent performing different behaviors on C and E pads were video-recorded [the time of video recording was relative to litter (feed) delivery on the scratch pads] for a total of 10 min/d, 3 times/wk, over a period of 4 weeks. Overall, the allocation of the time budget for different behaviors was found to be-in order of greatest to least amount of time-resting, locomotor behaviors (walking and running), foraging, and dust bathing. Laying hens showed a relative preference for E scratch pads by visiting them more frequently (P = 0.001), and spent more time (P = 0.035) foraging on them, whereas they rested for more time (P hens. Similarly, the longer use of C scratch pads for resting indicates the need for an ideal and clean resting surface in enriched cages.

Grizzly bear

Science.gov (United States)

Schwartz, C.C.; Miller, S.D.; Haroldson, M.A.; Feldhamer, G.; Thompson, B.; Chapman, J.

2003-01-01

The grizzly bear inspires fear, awe, and respect in humans to a degree unmatched by any other North American wild mammal. Like other bear species, it can inflict serious injury and death on humans and sometimes does. Unlike the polar bear (Ursus maritimus) of the sparsely inhabited northern arctic, however, grizzly bears still live in areas visited by crowds of people, where presence of the grizzly remains physically real and emotionally dominant. A hike in the wilderness that includes grizzly bears is different from a stroll in a forest from which grizzly bears have been purged; nighttime conversations around the campfire and dreams in the tent reflect the presence of the great bear. Contributing to the aura of the grizzly bear is the mixture of myth and reality about its ferocity. unpredictable disposition, large size, strength, huge canines, long claws, keen senses, swiftness, and playfulness. They share characteristics with humans such as generalist life history strategies. extended periods of maternal care, and omnivorous diets. These factors capture the human imagination in ways distinct from other North American mammals. Precontact Native American legends reflected the same fascination with the grizzly bear as modern stories and legends (Rockwell 1991).

47 CFR 80.309 - Watch required by the Bridge-to-Bridge Act.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Watch required by the Bridge-to-Bridge Act. 80... Safety Watches § 80.309 Watch required by the Bridge-to-Bridge Act. In addition to the watch requirement contained in § 80.148, all vessels subject to the Bridge-to-Bridge Act must keep a watch on the designated...

A Study on quality improvement and application technology in pad-mounted transformers

Energy Technology Data Exchange (ETDEWEB)

Kim, Soon Tae; Mun, Kyung Hwa; Jung, Dong Won; Kim, Sang Jun; Lee, Nam Woo; Kang, Nae Kuk; Kim, Dong Mung [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Kim, Kwang Ha; Kang, Young Sik; Lee, Woo Young; Lyu, Hee Suk; Sun, Jong Ho; Lyu, Hyung Ki; Kim, Yik Soo; Park, Sung Jae; Kim, Won Ho [Korea Electrotechnology Research Inst., Changwon (Korea, Republic of)

1995-12-31

In order to increase the reliability of pad-mounted transformers, the authors investigated operating condition of pad-mounted transformers and understood their failure mechanisms. The objective of their study was to improve quality and operating condition and install switches to be able to check and maintain transformers and optimise protection devices and increase cooling effect in pad-mounted transformers (author). 65 refs., 130 figs.

Toxicity and mutagenicity of low-metallic automotive brake pad materials.

Science.gov (United States)

Malachova, Katerina; Kukutschova, Jana; Rybkova, Zuzana; Sezimova, Hana; Placha, Daniela; Cabanova, Kristina; Filip, Peter

2016-09-01

Organic friction materials are standardly used in brakes of small planes, railroad vehicles, trucks and passenger cars. The growing transportation sector requires a better understanding of the negative impact related to the release of potentially hazardous materials into the environment. This includes brakes which can release enormous quantities of wear particulates. This paper addresses in vitro detection of toxic and mutagenic potency of one model and two commercially available low-metallic automotive brake pads used in passenger cars sold in the EU market. The model pad made in the laboratory was also subjected to a standardized brake dynamometer test and the generated non-airborne wear particles were also investigated. Qualitative "organic composition" was determined by GC/MS screening of dichloromethane extracts. Acute toxicity and mutagenicity of four investigated sample types were assessed in vitro by bioluminescence assay using marine bacteria Vibrio fischeri and by two bacterial bioassays i) Ames test on Salmonella typhimurium His(-) and ii) SOS Chromotest using Escherichia coli PQ37 strain. Screening of organic composition revealed a high variety of organic compounds present in the initial brake pads and also in the generated non-airborne wear debris. Several detected compounds are classified by IARC as possibly carcinogenic to humans, e. g. benzene derivatives. Acute toxicity bioassay revealed a response of bacterial cells after exposure to all samples used. Phenolic resin and wear debris were found to be acutely toxic; however in term of mutagenicity the response was negative. All non-friction exposed brake pad samples (a model pad and two commercial pad samples) were mutagenic with metabolic activation in vitro. Copyright © 2016 Elsevier Inc. All rights reserved.

The SciencePAD treasure hunt of Persistent Identifiers

CERN Multimedia

Beatrice Bressan, for the European Middleware Initiative (EMI)

2013-01-01

Have you ever followed a reference for an article that eventually turned out to be unavailable? Have you always thought that experiment data or research results should be permanently accessible? If so, you will probably be interested in the latest news on the current status of software and digital information issues, and you shouldn’t miss the SciencePAD Persistent Identifiers Workshop (SPID2013).   The workshop is being organised by the European Middleware Initiative (EMI) together with its SciencePAD (formerly known as ScienceSoft) project and will take place on 30 January 2013 at CERN. SciencePAD is a community-enabler, working on providing the necessary one-stop-shop tools, including software, catalogues, statistics, reference citation systems, marketplaces, technical services links, platform integration supports, etc. It allows researchers and open source software developers from scientific communities to interact with each other within and beyond their area of expertise, and co...

A Scott bench with ergonomic thorax stabilisation pad improves body posture during preacher arm curl exercise.

Science.gov (United States)

Biscarini, Andrea; Benvenuti, Paolo; Busti, Daniele; Zanuso, Silvano

2016-05-01

We assessed whether the use of an ergonomic thorax stabilisation pad, during the preacher arm curl exercise, could significantly reduce the excessive shoulder protraction and thoracic kyphosis induced by the standard flat pad built into the existing preacher arm curl equipment. A 3D motion capture system and inclinometers were used to measure shoulder protraction and thoracic kyphosis in 15 subjects performing preacher arm curl with a plate-loaded machine provided with the standard flat pad. The same measures were repeated after replacing the flat pad with a new ergonomic pad, specifically designed to accommodate the thorax profile and improve body posture. Pad replacement significantly (p ergonomic pad may potentially allow a more effective training, prevent musculoskeletal discomfort and reduce the risk of injury. Practitioner summary: We have designed an ergonomic thorax stabilisation pad for the preacher arm curl exercise. The new ergonomic pad improves the poor posture conditions induced by the standard flat pad and may potentially allow a more effective training, prevent musculoskeletal discomfort, improve the breathing function and reduce the risk of injury.

The PAD Class: a new paradigm for university classroom teaching

Science.gov (United States)

Zhang, Xuexin

2017-08-01

The PAD Class (Presentation-Assimilation-Discussion) is a new paradigm for classroom teaching combining strengths of lecture and discussion. With half class time allocated for teacher's presentation and the other half for students' discussion, an assimilation stage was inserted between presentation and discussion for independent and individualized learning. Since its first success in 2014, the PAD method has gained national popularity in China and been successfully put into practice by thousands of college teachers in nearly all subjects, e.g., science, engineering, medical sciences, social sciences, humanities and arts. This paper analyzed the psychological and pedagogical rationales underlying the PAD Class to explicate its effectiveness in enhancing active learning.

Construction and characterization of the TL/TH thorium calibration pads

International Nuclear Information System (INIS)

Steele, W.D.

1987-09-01

The Technical Measurements Center (TMC) was established and was tasked with developing and/or recommending measurement methods for use in support of remedial action programs. Since one aspect of this technical support is the provision of calibration facilities for standardization of field measurements, four sets of thorium-232 enriched pads (two pads per set) were constructed for use by remedial action contractors in calibrating portable field instruments that are used to make direct, in-situ measurements of radium-226, thorium-232, and potassium-40. This report presents the design, construction, and characterization data of the eight calibration pads. 17 refs., 8 figs., 15 tabs

Towards reducing impact-induced brain injury: lessons from a computational study of army and football helmet pads.

Science.gov (United States)

Moss, William C; King, Michael J; Blackman, Eric G

2014-01-01

We use computational simulations to compare the impact response of different football and U.S. Army helmet pad materials. We conduct experiments to characterise the material response of different helmet pads. We simulate experimental helmet impact tests performed by the U.S. Army to validate our methods. We then simulate a cylindrical impactor striking different pads. The acceleration history of the impactor is used to calculate the head injury criterion for each pad. We conduct sensitivity studies exploring the effects of pad composition, geometry and material stiffness. We find that (1) the football pad materials do not outperform the currently used military pad material in militarily relevant impact scenarios; (2) optimal material properties for a pad depend on impact energy and (3) thicker pads perform better at all velocities. Although we considered only the isolated response of pad materials, not entire helmet systems, our analysis suggests that by using larger helmet shells with correspondingly thicker pads, impact-induced traumatic brain injury may be reduced.

Field performance of timber bridges. 7, Connell Lake stress-laminated deck bridge

Science.gov (United States)

L. E. Hislop; M. A. Ritter

The Connell Lake bridge was constructed in early 1991 on the Tongass National Forest, Alaska, as a demonstration bridge under the Timber Bridge Initiative. The bridge is a stress-laminated deck structure with an approximate 36-ft length and 18-ft width and is the first known stress-laminated timber bridge constructed in Alaska. Performance of the bridge was monitored...

The Tablet Inscribed: Inclusive Writing Instruction with the iPad

Science.gov (United States)

Sullivan, Rebecca M.

2013-01-01

Despite the author's initial skepticism, a classroom set of iPads has reinforced a student-directed approach to writing instruction, while also supporting an inclusive classroom. Using the iPads, students guide their writing process with access to the learning management system, electronic information resources, and an online text editor. Students…

Track-Bridge Longitudinal Interaction of Continuous Welded Rails on Arch Bridge

Directory of Open Access Journals (Sweden)

Rong Chen

2013-01-01

Full Text Available Taking arch bridges, including deck, half-through, and through arch bridges (short for DAB, HTAB, and TAB as examples, mechanics analysis models of longitudinal interaction between continuously welded rails (short for CWRs and arch bridges are established. Based on the finite element method (FEM, the longitudinal interaction calculation software of CWR on arch bridges has been developed. Focusing on an HTAB, the tension, compression, and deflection conditions are calculated and analyzed. The results show that the mechanics analysis models of three types of arch bridges can truly reflect the real state of the structure; the calculation software can be used for systematic research of the CWR on arch bridge; as for HTAB, temperature difference of arch rib has a small effect on rail tension/compression, and arch bridge can be simplified as a continuous beam for rail tension/compression additional force calculation; in calculation of deflection conditions of HTAB, it is suggested that train loads are arranged on half span and full span and take the direction of load entering bridge into account. Additionally, the deflection additional force variation of CFST basket handle arch bridge is different from that of ordinary bridge.

SCIENTIFIC PROGRESS OF THE MC-PAD NETWORK

CERN Document Server

Aguilar, J; Ambalathankandy, P; Apostolakis, J; Arora, R; Balog, T; Behnke, T; Beltrame, P; Bencivenni, G; Caiazza, S; Dong, J; Heller, M; Heuser, J; Idzik, M; Joram, C; Klanner, R; Koffeman, E; Korpar, S; Kramberger, G; Lohmann, W; Milovanović, M; Miscetti, S; Moll, M; Novgorodova, O; Pacifico, N; Pirvutoiu, C; Radu, R; Rahman, S; Rohe, T; Ropelewski, L; Roukoutakis, F; Schmidt, C; Schön, R; Sibille, J; Tsagri, M; Turala, M; Van Beuzekom, M; Verheyden, R; Villa, M; Zappon, F; Zawiejski, L; Zhang, J

2013-01-01

MC-PAD is a multi-site Initial Training Network on particle detectors in physics experiments. It comprises nine academic participants, three industrial partners and two associated academic partners. 17 recruited Early Stage and 5 Experienced Researchers have performed their scientific work in the network. The research and development work of MC-PAD is organized in 12 work packages, which focus on a large variety of aspects of particle detector development, electronics as well as simulation and modelling. The network was established in November 2008 and lasted until October 2012 (48 months). This report describes the R&D activities and highlights the main results achieved during this period.

Use of an iPad to Provide Warfarin Video Education to Hospitalized Patients.

Science.gov (United States)

Kim, Jenny Jane; Mohammad, Rima A; Coley, Kim C; Donihi, Amy C

2015-09-01

To evaluate the effectiveness of a warfarin educational video in the hospital setting and to determine patients' satisfaction with using an iPad to view a warfarin educational video. This prospective quality improvement project included adult (≥18 years of age) patients on warfarin in the hospital. All patients completed pre-video and post-video knowledge tests on the iPad before and after viewing the educational video on warfarin therapy. Patients also completed a patient satisfaction survey. Forty hospitalized patients were educated using the warfarin video and included for analysis. The majority of patients were new to warfarin therapy (65%). Forty-three percent of patients passed the pre-video knowledge test, and 90% passed the post-video knowledge test (P iPad and found it easy to use. Patients who were younger (iPad more than older patients (P = 0.01) and male subjects (P = 0.02), respectively. Also, younger patients found the iPad easier to use compared with patients who were older (P = 0.01). Educating hospitalized patients about warfarin by using a video on an iPad was effective. Video education on an iPad may be an alternative to traditional education in the hospital setting.

Knee Fat Pad Volumes in Patients with Hemophilia and Their Relationship with Osteoarthritis

Directory of Open Access Journals (Sweden)

Annette von Drygalski

2017-01-01

Full Text Available Hemophilic arthropathy is a progressive, disabling condition with poorly understood pathobiology. Since there is an emerging interest to study the role of intra-articular fat pad size and biology in arthritic conditions, we explored fat pad volume changes in hemophilic arthropathy and to what extent they differed from osteoarthritis. We matched a cohort of 13 adult patients with hemophilic arthropathy of the knee with age- and gender-matched cohorts without osteoarthritis (“control cohort” and with the same degree of radiographic osteoarthritis (“OA cohort” in 1 : 2 fashion. Infrapatellar fat pad (IPFP and suprapatellar fat pad (SPFP volumes were calculated based on magnetic resonance imaging and differences in fat pad volumes, demographics, height, weight, and osteoarthritis scores were evaluated. Fat pad volumes were positively associated with body size parameters in all three cohorts but were unaffected by the degree of osteoarthritis. While IPFP volumes did not differ between cohorts, SPFP volumes expanded disproportionally with weight in hemophilia patients. Our observations indicate that IPFPs and SPFPs behave biologically differently in response to different arthritic stimuli. The exaggerated expansion of the SPFP in hemophilia patients highlights the importance of further studying the implications of fat pad biology for progression of hemophilic arthropathy.

TID Test Results for 4th Generation iPad(TradeMark)

Science.gov (United States)

Guertin, S. M.; Allen, G. R.; McClure, S. S.; LaBel, K. A.

2013-01-01

TID testing of 4th generation iPads is reported. Of iPad subsystems, results indicate that the charging circuitry and display drivers fail at lowest TID levels. Details of construction are investigated for additional testing of components.

Self-supporting method; an alternative method for steel truss bridge element replacement

Science.gov (United States)

Arsyad, Muhammad; Sangadji, Senot; As'ad, Sholihin

2017-11-01

Steel truss bridge often requires replacement of its element due to serious damage caused by traffic accidents. This replacement is carried out using temporary supporting structure. It would be difficult when the available space for the temporary structure is quite limited and or the position of work is at a high elevation. The self-supporting method is proposed instead of temporary supporting structure. This paper will discuss an innovative method of bridge rehabilitation by utilizing the existing bridge structure. It requires such temporary connecting structure that installed on the existing bridge element, therefore, the forces during replacement process could be transferred to the bridge foundation directly. By taking the case on a steel truss bridge Jetis Salatiga which requires element replacement due to its damages on two main diagonals, a modeling is carried out to get a proper repair method. Structural analysis is conducted for three temporary connecting structure models: “I,” “V,” and triangular model. Stresses and translations that occur in the structure are used as constraints. Bridge bearings are modeled in two different modes: fixed-fixed system and fixed-free one. Temperature load is given in each condition to obtain the appropriate time for execution. The triangular model is chosen as the best one. In the fixed-fixed mode, this method can be carried out in a temperature range 27-28.8° C, while in fixed-free one, the temperature it is allowed between 27-43.4 °C. The D4 is dismantled first by cutting the D4 leaving an area of 1140.2 mm2 or 127 mm web length to enable plastic condition until the D4 collapses. At the beginning of elongation occurs, immediately performed a slowly jacking on a temporary connecting structure so that the force on D4 is gradually transferred to the temporary connecting structure then the D4 and D5 are set in their place.

On the comparison between MRI and US imaging for human heel pad thickness measurements

DEFF Research Database (Denmark)

Matteoli, Sara; Corbin, Nadège Corbin; Wilhjelm, Jens E.

2011-01-01

The human heel pad thickness, defined as the shortest distance between the calcaneus and heel skin, is one of the intrinsic factor which must be taken into account when investigating the biomechanics of the heel pad. US and MRI are the preferable imaging modalities used to measure the heel pad...... thickness as they are both ionizing-free radiations. The aim of this paper is to measure the bone to skin distance of nine heel pad phantoms from MRI and US images, and to compare the results with a true value (TV) in order to find the errors. Paired sample t-test was used to compare the measurements......1530 (P-value=0.402). Results confirm the necessity to investigate on the real speed of sound for the heel pad tissues, in order to have realistic measurements when dealing with human heel pads. __________________________________________________________________________________________________________...

SCiPad: Effective Implementation of Telemedicine Using iPads with Individuals with Spinal Cord Injuries, a Case Series

Directory of Open Access Journals (Sweden)

Kazuko Shem

2017-05-01

Full Text Available BackgroundIndividuals with spinal cord injury (SCI must often travel long distances to see a rehabilitation specialist. While telemedicine (TM for pressure ulcer management has been used in this population, real-time video telecommunication using iPad has never been described.ObjectiveThe objective of this study was to provide specialized care for persons with SCI through TM consultation expediently in order to address medical needs, manage secondary complications, and to improve quality of life (QoL of individuals with SCI.MethodsTen individuals with SCI participated in the TM program using iPads for 6 months as a feasibility study at a single-center, county hospital. The participants contacted the project staff for SCI-related conditions and were then connected to an SCI-trained health-care provider within 24 hours via FaceTime. Main outcome measures included health-care utilization; QoL and psychosocial measures collected at baseline and at 6 months: Reintegration to Normal Living Index (RNLI, Life Satisfaction Index A (LSI-A, and Patient Health Questionnaire 9 (PHQ-9; and a Program Satisfaction Survey.ResultsTen patients (seven with tetraplegia, three with paraplegia; eight males and two females with an average age of 34.4 (18–54 years were enrolled. The average baseline and 6-month follow-up scores were RNLI—70.1 ± 19.7 and 74.7 ± 21.8, respectively; LSI-A—25.4 ± 7.4 and 26.4 ± 8.2, respectively; and PHQ-9 were 6.8 ± 7.2 and 8.6 ± 6.1, respectively. TM encounters included topics such as pain, bladder and skin management, medication changes, and lab results. The Program Satisfaction Survey yielded positive results with 100% of program completers stating they would recommend the program and would like to continue having TM.ConclusionThis is the first known successful project using iPad to provide TM in the SCI population. This study discusses the implementation of such a TM program in a health system

Metal-core pad-plane development for ACTAR TPC

Science.gov (United States)

Giovinazzo, J.; Pibernat, J.; Goigoux, T.; de Oliveira, R.; Grinyer, G. F.; Huss, C.; Mauss, B.; Pancin, J.; Pedroza, J. L.; Rebii, A.; Roger, T.; Rosier, P.; Saillant, F.; Wittwer, G.

2018-06-01

With the recent development of active targets and time projection chambers (ACTAR TPC) as detectors for fundamental nuclear physics experiments, the need arose for charge collection planes with a high density of readout channels. In order to fulfill the mechanical constraints for the ACTAR TPC device, we designed a pad-plane based on a metal-core circuit with an conceptually simple design and routing for signal readout, named FAKIR (in reference to a fakir bed of nails). A test circuit has been equipped with a micro mesh gaseous structure (micromegas) for signal amplification and a dedicated readout electronics. Test measurements have been performed with an 55Fe X-ray source giving an intrinsic energy resolution (FWHM) of 22 ± 1% at 5 . 9 keV, and with a 3-alpha source for which a resolution of about 130 ± 20 keV at 4 . 8 MeV has been estimated. The pad-plane has been mounted into a reduced size demonstrator version of the ACTAR TPC detector, in order to illustrate charged particle track reconstruction. The tests preformed with the X-ray and the 3-alpha sources shows that results obtained from pads signals are comparable to the intrinsic result from the micro-mesh signal. In addition, a simple alpha particle tracks analysis is performed to demonstrate that the pad plane allows a precise reconstruction of the direction and length of the trajectories.

77 FR 70423 - Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC...

Science.gov (United States)

2012-11-26

... Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of..., 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor) and Black Bear Development Holdings, LLC and Black Bear SO, LLC (transferees) filed an application for the partial the transfer of licenses...

The Neglected "R": Improving Writing Instruction through iPad Apps

Science.gov (United States)

Sessions, Laird; Kang, Mi Ok; Womack, Sue

2016-01-01

In this study the authors investigated the effects of integrating iPad applications into writing instruction for fifth grade students. By comparing the writing of students taught with paper and pencil methods with that of students utilizing the iPad writing applications, two research questions guided the study: (1) Are there differences in student…

Construction and characterization of the RH/RL radium calibration pads

International Nuclear Information System (INIS)

Steele, W.D.; Marutzky, S.J.; Dickerson, J.W.

1989-01-01

The US Department of Energy (DOE) Office of Remedial Action and Waste Technology has as one of its goals the standardization of field measurements made by its remedial action contractors throughout the country. In support of this goal, the Technical Measurements Center (TMC) was established at the DOE Grand Junction Projects Office (GJPO) Facility, and was tasked with developing and/or recommending measurement methods for use in support of remedial action programs. One aspect of this technical support is the provision of calibration facilities for standardization of field measurements. The report presents the results of the design, construction, and characterization of 14 calibration pads enriched in radium-226. The 14 pads comprise 7 sets with a high and low activity pad in each set. The pads are concrete cylinders, approximately 5 feet in diameter by 2 feet in height. They are intended for use in calibrating portable field instruments that are used by remedial action contractors to make direct, in situ measurements of radium-226, thorium-232, and potassium-40. 23 refs., 6 figs., 14 tabs

Phylogeography of mitochondrial DNA variation in brown bears and polar bears.

Science.gov (United States)

Shields, G F; Adams, D; Garner, G; Labelle, M; Pietsch, J; Ramsay, M; Schwartz, C; Titus, K; Williamson, S

2000-05-01

We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples. Copyright 2000 Academic Press.

Phylogeography of mitochondrial DNA variation in brown bears and polar bears

Science.gov (United States)

Shields, Gerald F.; Adams, Deborah; Garner, Gerald W.; Labelle, Martine; Pietsch, Jacy; Ramsay, Malcolm; Schwartz, Charles; Titus, Kimberly; Williamson, Scott

2000-01-01

We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples.

Use of Doceri Software for iPad in Online Delivery of Chemistry Content

Science.gov (United States)

Silverberg, Lee J.; Tierney, John; Bodek, Matthew J.

2014-01-01

Doceri software for iPad is useful for both synchronous online and asynchronous online delivery of chemistry course content. Using the Doceri wireless connection between the iPad and a personal computer that is running Adobe Connect, online synchronous instruction can be accomplished in which drawings can be completed by hand on the iPad. For…

Exploring the Use of the iPad for Literacy Learning

Science.gov (United States)

Hutchison, Amy; Beschorner, Beth; Schmidt-Crawford, Denise

2012-01-01

The goal of this investigation was to explore how a fourth grade teacher could integrate iPads into her literacy instruction to simultaneously teach print-based and digital literacy goals. The teacher used iPads for a three-week period during her literacy instruction and selected apps that provided unique approaches to helping the students meet…

Another Perspective: The iPad Is a REAL Musical Instrument

Science.gov (United States)

Williams, David A.

2014-01-01

This article looks at the iPad's role as a musical instrument through the lens of a live performance ensemble that performs primarily on iPads. It also offers an overview of a pedagogical model used by this ensemble, which emphasizes musician autonomy in small groups, where music is learned primarily through aural means and concerts are…

Engaging Organic Chemistry Students Using ChemDraw for iPad

Science.gov (United States)

Morsch, Layne A.; Lewis, Michael

2015-01-01

Drawing structures, mechanisms, and syntheses is a vital part of success in organic chemistry courses. ChemDraw for iPad has been used to increase classroom experiences in the preparation of high quality chemical drawings. The embedded Flick-to-Share allows for simple, real-time exchange of ChemDraw documents. ChemDraw for iPad also allows…

Parametric Study on Responses of a Self-Anchored Suspension Bridge to Sudden Breakage of a Hanger

Directory of Open Access Journals (Sweden)

Wenliang Qiu

2014-01-01

Full Text Available The girder of self-anchored suspension bridge is subjected to large compression force applied by main cables. So, serious damage of the girder due to breakage of hangers may cause the collapse of the whole bridge. With the time increasing, the hangers may break suddenly for their resistance capacities decrease due to corrosion. Using nonlinear static and dynamic analysis methods and adopting 3D finite element model, the responses of an actual self-anchored suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of a hanger causes violent vibration and large changes in internal forces of the bridge. In the process of the vibration, the maximum tension of hanger produced by breakage of a hanger exceeds 2.22 times its initial value, and the reaction forces of the bearings increase by more than 1.86 times the tension of the broken hanger. Based on the actual bridge, the influences of some factors including flexural stiffness of girder, torsion stiffness of girder, flexural stiffness of main cable, weight of girder, weight of main cable, span to sag ratio of main cable, distance of hangers, span length, and breakage time of hanger on the dynamic responses are studied in detail, and the influencing extent of the factors is presented.

Parametric study on responses of a self-anchored suspension bridge to sudden breakage of a hanger.

Science.gov (United States)

Qiu, Wenliang; Jiang, Meng; Huang, Cailiang

2014-01-01

The girder of self-anchored suspension bridge is subjected to large compression force applied by main cables. So, serious damage of the girder due to breakage of hangers may cause the collapse of the whole bridge. With the time increasing, the hangers may break suddenly for their resistance capacities decrease due to corrosion. Using nonlinear static and dynamic analysis methods and adopting 3D finite element model, the responses of an actual self-anchored suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of a hanger causes violent vibration and large changes in internal forces of the bridge. In the process of the vibration, the maximum tension of hanger produced by breakage of a hanger exceeds 2.22 times its initial value, and the reaction forces of the bearings increase by more than 1.86 times the tension of the broken hanger. Based on the actual bridge, the influences of some factors including flexural stiffness of girder, torsion stiffness of girder, flexural stiffness of main cable, weight of girder, weight of main cable, span to sag ratio of main cable, distance of hangers, span length, and breakage time of hanger on the dynamic responses are studied in detail, and the influencing extent of the factors is presented.

Crystal structures of titanium–aluminium and –gallium complexes bearing two μ2-CH3 units

Directory of Open Access Journals (Sweden)

Tim Oswald

2017-05-01

Full Text Available The isotypic crystal structures of two titanocene complexes containing an EMe3 unit (E = Al, Ga; Me = methyl with two μ2-coordinating methyl groups, namely [μ-1(η5-(adamantan-1-yl-2κC1cycylopentadienyl]di-μ2-methyl-methyl-2κC-[1(η5-pentamethylcyclopentadienyl]aluminiumtitanium(III, [AlTi(CH33(C10H15(C15H18], and [μ-1(η5-(adamantan-1-yl-2κC1cycylopentadienyl]di-μ2-methyl-methyl-2κC-[1(η5-pentamethylcyclopentadienyl]galliumtitanium(III, [GaTi(CH33(C10H15(C15H18], are reported. Reacting a dinuclear nitrogen-bridged low-valent titanium(III complex with the Lewis acids AlMe3 or GaMe3 results in the loss of molecular dinitrogen and the formation of two monomeric titanocene(III fragments bearing two μ2-bridging methyl groups. Single crystal X-ray diffraction reveals the formation of a new E—C bond involving the pentafulvene ligand while the bridging and terminal methyl groups remain intact.

ATLANTIS ROLLS OUT TO PAD 39A FOLLOWING HURRICANE FRAN THREAT

Science.gov (United States)

1996-01-01

A view from the flame trench looking up shows the Space Shuttle Atlantis, mounted on the Mobile Launcher Platform and Crawler- Transporter, as it arrives atop the hardstand at Launch Pad 39A. After the Shuttle and launch stand are in position, the crawler will be pulled back. This is the third time Atlantis has completed the journey to Launch Pad 39A in the STS-79 mission flow. The Shuttle was rolled back from the pad in July due to the threat from Hurricane Bertha, then rolled back again earlier this week because of Hurricane Fran. The targeted launch date for Atlantis on Mission STS-79 -- the fourth docking between the U.S. Shuttle and Russian Space Station Mir -- is now Sept. 16 at 4:54 a.m. EDT. The three rollout dates for Atlantis to Pad 39A are: July 1, Aug. 20 and Sept. 5.

University staff adoption of iPads: An empirical study using an extended TAM model

Directory of Open Access Journals (Sweden)

Michael Steven Lane

2014-11-01

Full Text Available This research examined key factors influencing adoption of iPads by university staff. An online survey collected quantitative data to test hypothesised relationships in an extended TAM model. The findings show that university staff consider iPads easy to use and useful, with a high level of compatibility with their work. Social status had no influence on their attitude to using an iPad. However older university staff and university staff with no previous experience in using a similar technology such as an iPhone or smartphone found iPads less easy to use. Furthermore, a lack of formal end user ICT support impacted negatively on the use of iPads.

Introgressive hybridization: brown bears as vectors for polar bear alleles.

Science.gov (United States)

Hailer, Frank

2015-03-01

The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male-biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture-free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach. © 2015 John Wiley & Sons Ltd.

A hinged-pad test structure for sliding friction measurement in micromachining

Energy Technology Data Exchange (ETDEWEB)

Boer, M.P. de; Redmond, J.M.; Michalske, T.A.

1998-08-01

The authors describe the design, modeling, fabrication and initial testing of a new test structure for friction measurement in MEMS. The device consists of a cantilevered forked beam and a friction pad attached via a hinge. Compared to previous test structures, the proposed structure can measure friction over much larger pressure ranges, yet occupies one hundred times less area. The placement of the hinge is crucial to obtaining a well-known and constant pressure distribution in the device. Static deflections on the device were measured and modeled numerically, Preliminary results indicate that friction pad slip is sensitive to friction pad normal force.

Bridges

NARCIS (Netherlands)

Zant, W.

2017-01-01

We estimate to what extent bridges in Mozambique lead to transport cost reductions and attribute these reductions to key determinants, in particular road distance, road quality and crossing borders. For identification we exploit the introduction of a road bridge over the Zambezi river, in August

MWPC with highly segmented cathode pad readout

International Nuclear Information System (INIS)

Debbe, R.; Fischer, J.; Lissauer, D.

1989-01-01

Experiments being conducted with high energy heavy ion beams at Brookhaven National Laboratory and at CERN have shown the importance of developing position sensitive detectors capable of handling events with high multiplicity in environments of high track density as will also be the case in future high luminosity colliders like SSC and RHIC. In addition, these detectors are required to have a dynamic range wide enough to detect minimum ionizing particles and heavy ions like oxygen or silicon. We present here a description of work being done on a prototype of such a detector at BNL. Results from a similar counter are also presented in this Conference. The ''pad chamber'' is a detector with a cathode area subdivided into a very large number of pixel-like elements such that a charged particle traversing the detector at normal incidence leaves an induced charge on a few localized pads. The pads are interconnected by a resistive strip, and readout amplifiers are connected to the resistive strip at appropriate, carefully determined spacings. The pattern of tracks in a multi-hit event is easily recognized, and a centroid-finding readout system allows position determination to a small fraction of the basic cell size. 5 refs., 9 figs

Placement of the Left Side AED Pad is Poor: Training on the Left Compared to the Right Side of a Manikin Does Not Improve Pad Placement

DEFF Research Database (Denmark)

Stærk, Mathilde; Bødtker, Henrik; Rahbek, Søren

2015-01-01

participating in a first aid course were randomized to learn automated external defibrillation sitting on the left or right side of a manikin during AED training. After course completion participants operated a training AED (Lifepak® CR-T AED Trainer, PhysioControl) and placed AED pads according to instructions...... volunteers were included and randomized to AED training on the left (n=14, 43% male, age: 47.9 years) and right (n=16, 25% male, age: 46.7 years) side of a manikin. There was no difference in left pad placement when trained on the left or right side (distance to recommended left apical pad position (mean...

Focused Molding Using Adhesive Pads in Mehta Casting for Early-Onset Scoliosis.

Science.gov (United States)

Abraham, Roby; Sponseller, Paul D

2014-11-01

Prospective clinical series. To determine the effect of adhesive pads placed over the apex of scoliosis curves on curve correction 1) after the first cast and 2) after the final cast. Early-onset scoliosis is often effectively managed by serial casting. Properly localizing the apex of the molds with the cast in place is challenging. The authors explored the effectiveness of a novel technique: incorporation of adhesive pads placed over the major curve apex before Mehta casting. The 27 patients who received body casts (2000-2013) were divided into 2 groups: those without and with apical adhesive pads (5-6 layers of pads placed on the major curve's apex during casting): non-pad (NP) group (n = 12) and pad (P) group (n = 15), respectively. Groups were compared regarding the percentage of Cobb angle change from the first cast and curve correction to a Cobb angle of cast curve correction was 39% ± 18% and 56% ± 17% in the NP and P groups, respectively. Of the 26 patients out of a cast, 11 (42%) had a Cobb angle of casting were effective in increasing the amount of major curve correction from the first cast for idiopathic early-onset scoliosis and in decreasing curves to <25° at final follow-up. Copyright © 2014 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.

Expanding the role of the iPad and tablet devices to cosmetic patient consultations.

Science.gov (United States)

Wang, Jing; Hsu, Jeffrey T S; Bhatia, Ashish C

2012-09-01

The iPad is a useful reference tool for patient education in cosmetic consultations. In this article, we plan to (1) discuss how the iPad can be implemented and used by patients and physicians in consultations, (2) compare the advantages and disadvantages of the iPad with other forms of technology, (3) discuss the optimal way of using the iPad for patient care, (4) see how this tool complies with privacy regulations, and (5) look at other uses of the iPad in the patient care setting. There has been positive feedback from both patients and physicians regarding the addition of the tablet computer during consultations. In addition to showing patients pictures of cosmetic procedures, the iPad also has various multimedia capabilities such as videos and drawing tools that are useful in optimizing patient satisfaction, increasing clinical efficacy, and improving the overall patient experience. Copyright © 2012. Published by Elsevier Inc.

Kinetic energy absorbing pad

International Nuclear Information System (INIS)

Bricmont, R.J.; Hamilton, P.A.; Ming Long Ting, R.

1981-01-01

Reactors, fuel processing plants etc incorporate pipes and conduits for fluids under high pressure. Fractures, particularly adjacent to conduit elbows, produce a jet of liquid which whips the broken conduit at an extremely high velocity. An enormous impact load would be applied to any stationary object in the conduit's path. The design of cellular, corrugated metal impact pads to absorb the kinetic energy of the high velocity conduits is given. (U.K.)

Method for Producing Launch/Landing Pads and Structures Project

Science.gov (United States)

Mueller, Robert P. (Compiler)

2015-01-01

Current plans for deep space exploration include building landing-launch pads capable of withstanding the rocket blast of much larger spacecraft that that of the Apollo days. The proposed concept will develop lightweight launch and landing pad materials from in-situ materials, utilizing regolith to produce controllable porous cast metallic foam brickstiles shapes. These shapes can be utilized to lay a landing launch platform, as a construction material or as more complex parts of mechanical assemblies.

ClimatePad: Enabling public exploration of climate data

Science.gov (United States)

Walsh, J. E.; Chapman, W. L.

2012-12-01

Informal learners interested in climate issues can find a wealth of information in the print and online media related to climate and climate change. Throughout these resources, the equal use of generic terms like 'global warming' and 'climate change' suggest a level of nuance in the science that is not easy to convey in this conventional media. Perhaps more than any other discipline, climate literacy has the most potential to be enhanced via the process of cognitive construction and reconstruction, rather than simple transmission of knowledge. Constructionism suggests that meaningful learning happens most effectively if the learner is actively engaged in constructing a product in the real world rather than absorbing information passively. Recent technological innovations have introduced mobile computing devices with sufficient power to do serious data analysis. The potential of these devices to augment climate literacy by turning citizens into scientists has yet to be exploited. We introduce ClimatePad, an iPad application that permits students and public to actively browse climate datasets, construct trends, plot time series, create composite differences and view animations of real-world climate data. Interactions with the ClimatePad permits varying the starting and ending dates of trends and differences. Climate analysis maps and animations can be customized with different color palettes, enticing the user to delve into and absorb the subtleties of the regional and temporal variations of the recent climate record. Finally, user-generated climate visualizations created with ClimatePad can be emailed to friends and shared via Facebook, entraining even more active learners.

Direct application of Padé approximant for solving nonlinear differential equations.

Science.gov (United States)

Vazquez-Leal, Hector; Benhammouda, Brahim; Filobello-Nino, Uriel; Sarmiento-Reyes, Arturo; Jimenez-Fernandez, Victor Manuel; Garcia-Gervacio, Jose Luis; Huerta-Chua, Jesus; Morales-Mendoza, Luis Javier; Gonzalez-Lee, Mario

2014-01-01

This work presents a direct procedure to apply Padé method to find approximate solutions for nonlinear differential equations. Moreover, we present some cases study showing the strength of the method to generate highly accurate rational approximate solutions compared to other semi-analytical methods. The type of tested nonlinear equations are: a highly nonlinear boundary value problem, a differential-algebraic oscillator problem, and an asymptotic problem. The high accurate handy approximations obtained by the direct application of Padé method shows the high potential if the proposed scheme to approximate a wide variety of problems. What is more, the direct application of the Padé approximant aids to avoid the previous application of an approximative method like Taylor series method, homotopy perturbation method, Adomian Decomposition method, homotopy analysis method, variational iteration method, among others, as tools to obtain a power series solutions to post-treat with the Padé approximant. 34L30.

Field performance of timber bridges. 4, Graves Crossing stress-laminated deck bridge

Science.gov (United States)

J. P. Wacker; M. A. Ritter

The Graves Crossing bridge was constructed October 1991 in Antrim County, Michigan, as part of the demonstration timber bridge program sponsored by the USDA Forest Service. The bridge is a two-span continuous, stress-laminated deck superstructure and it is 36-ft long and 26-ft wide. The bridge is one of the first stress-laminated deck bridges to be built of sawn lumber...

Physicochemical characterization of cactus pads from Opuntia dillenii and Opuntia ficus indica.

Science.gov (United States)

Méndez, Lorena Pérez; Flores, Fidel Tejera; Martín, Jacinto Darias; Rodríguez Rodríguez, Elena M; Díaz Romero, Carlos

2015-12-01

Physicochemical characteristics (weight, length, width, thickness, moisture, Brix degree, total fiber, protein, ash, pH, acidity, ascorbic acid, total phenolic compounds, P, Na, K, Ca, Mg, Fe, Cu, Zn, Mn and Cr) were determined in cactus pads from Opuntia dillenii and Opuntia ficus indica. The physicochemical characteristics of both species were clearly different. There were important differences between the orange and green fruit pulp of O. ficus indica; the cactus pads of O. dillenii could be differentiated according to the region (North and South). Consumption of cactus pads contributes to the intake of dietary fiber, total phenolic compounds, K, Mg, Mn and Cr. Applying factor and/or discriminant analysis, the cactus pad samples were clearly differentiated according to the species, the fruit pulp color and production region. Copyright © 2015 Elsevier Ltd. All rights reserved.

Myocardial Bridging

Directory of Open Access Journals (Sweden)

Shi-Min Yuan

2016-02-01

Full Text Available Abstract Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results.

The hepatic bridge.

Science.gov (United States)

Sugarbaker, Paul H

2018-07-01

The hepatic bridge forms a tunnel of liver parenchyma that may obscure peritoneal metastases associated with the round ligament. Visualization and then resection of nodules associated with this structure is necessary. The incidence of a hepatic bridge and the extent that it covered the round ligament was determined in consecutive patients. Extent of coverage of the round ligament by the hepatic bridge was determined: Class 1 indicates up to one-third of the round ligament obscured, Class 2 up to two-thirds and Class 3 more than two-thirds. In 102 patients in whom the round ligament of the liver could be completely visualized, 50 had a hepatic bridge. Class 1 was 22 (44%) of the bridges, Class 2 was 16 (32%) and Class 3 was 12 (24%). A hepatic bridge was more frequently present in 28 of 45 male patients (62%) vs. 22 of 57 female patients (38%). Approximately one-half of our patients having cytoreductive surgery for peritoneal metastases were observed to have a hepatic bridge. Up to 56% of these patients have Class 2 or 3 hepatic bridge and may require division of the hepatic bridge to completely visualize the contents of the tunnel created by this structure. Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

Dermal exposure assessment to benzene and toluene using charcoal cloth pads

NARCIS (Netherlands)

Wendel de Joode, B. van; Tielemans, E.; Vermeulen, R.; Wegh, H.; Kromhout, H.

2005-01-01

Charcoal cloth pads have been used to assess volatile chemicals on the skin in a laboratory setting; however, they have not yet been applied to measure dermal exposure in occupational settings. This study aimed at evaluating whether charcoal pads can be used to assess dermal exposure to benzene and

Measuring contact area in a sliding human finger-pad contact.

Science.gov (United States)

Liu, X; Carré, M J; Zhang, Q; Lu, Z; Matcher, S J; Lewis, R

2018-02-01

The work outlined in this paper was aimed at achieving further understanding of skin frictional behaviour by investigating the contact area between human finger-pads and flat surfaces. Both the static and the dynamic contact areas (in macro- and micro-scales) were measured using various techniques, including ink printing, optical coherence tomography (OCT) and Digital Image Correlation (DIC). In the studies of the static measurements using ink printing, the experimental results showed that the apparent and the real contact area increased with load following a piecewise linear correlation function for a finger-pad in contact with paper sheets. Comparisons indicated that the OCT method is a reliable and effective method to investigate the real contact area of a finger-pad and allow micro-scale analysis. The apparent contact area (from the DIC measurements) was found to reduce with time in the transition from the static phase to the dynamic phase while the real area of contact (from OCT) increased. The results from this study enable the interaction between finger-pads and contact object surface to be better analysed, and hence improve the understanding of skin friction. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Bridge resource program.

Science.gov (United States)

2013-09-01

The mission of Rutgers Universitys Center for Advanced Infrastructure and Transportation (CAIT) Bridge Resource Program (BRP) is to provide bridge engineering support to the New Jersey Department of Transportation (NJDOT)s Bridge Engineering an...

Bridged graphite oxide materials

Science.gov (United States)

Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

2010-01-01

Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

The use of an iPad to collect patient-reported functional outcome measures in hand surgery.

Science.gov (United States)

Yaffe, Mark; Goyal, Nitin; Kokmeyer, Daniel; Merrell, Gregory A

2015-09-01

The purpose of this study was to evaluate (1) patient preferences regarding iPad and paper-based questionnaires, (2) the efficacy of iPad and paper questionnaires in a hand surgery practice, (3) the influence of questionnaire length on patient preferences and data collection, and (4) patient characteristics associated with a preference for iPad-based questionnaires. Two hundred total patients in a single hand surgery practice were randomly assigned to one of four groups. Each group completed either the Michigan Hand Questionnaire (MHQ) or QuickDASH (QD) using either an iPad or pen and paper. Patient preferences, questionnaire completion and timing, and demographic data were analyzed. The use of an iPad was associated with a statistically stronger preference for the same delivery format in the future compared to paper for the MHQ (93.9 vs 52.1 %, p iPad group found the survey "physically easy" more often compared to the MHQ paper group, while no difference was found among QD groups. Questionnaire timing between iPad and paper groups was similar for the MHQ but statistically longer with the iPad for QD. A significantly higher proportion of patients who preferred the iPad were under the age of 50 compared to those who preferred paper. The addition of an iPad is an efficient and preferable questionnaire format for functional outcome assessment in a hand and upper extremity surgery practice setting. The iPad is particularly preferable for longer outcome questionnaires and for patients under the age of 50.

Laboratory and field testing of an accelerated bridge construction demonstration bridge : US Highway 6 bridge over Keg Creek.

Science.gov (United States)

2013-04-01

The US Highway 6 Bridge over Keg Creek outside of Council Bluffs, Iowa is a demonstration bridge site chosen to put into practice : newly-developed Accelerated Bridge Construction (ABC) concepts. One of these new concepts is the use of prefabricated ...

Antimony leaching release from brake pads: Effect of pH, temperature and organic acids.

Science.gov (United States)

Hu, Xingyun; He, Mengchang; Li, Sisi

2015-03-01

Metals from automotive brake pads pollute water, soils and the ambient air. The environmental effect on water of antimony (Sb) contained in brake pads has been largely untested. The content of Sb in one abandoned brake pad reached up to 1.62×10(4) mg/kg. Effects of initial pH, temperature and four organic acids (acetic acid, oxalic acid, citric acid and humic acid) on Sb release from brake pads were studied using batch reactors. Approximately 30% (97 mg/L) of the total Sb contained in the brake pads was released in alkaline aqueous solution and at higher temperature after 30 days of leaching. The organic acids tested restrained Sb release, especially acetic acid and oxalic acid. The pH-dependent concentration change of Sb in aqueous solution was best fitted by a logarithmic function. In addition, Sb contained in topsoil from land where brake pads were discarded (average 9×10(3) mg/kg) was 3000 times that in uncontaminated soils (2.7±1 mg/kg) in the same areas. Because potentially high amounts of Sb may be released from brake pads, it is important that producers and environmental authorities take precautions. Copyright © 2015. Published by Elsevier B.V.

Guardrails for Use on Historic Bridges: Volume 2—Bridge Deck Overhang Design

OpenAIRE

Frosch, Robert J.; Morel, Adam J.

2016-01-01

Bridges that are designated historic present a special challenge to bridge engineers whenever rehabilitation work or improvements are made to the bridges. Federal and state laws protect historically significant bridges, and railings on these bridges can be subject to protection because of the role they play in aesthetics. Unfortunately, original railings on historic bridges do not typically meet current crash-test requirements and typically do not meet current standards for railing height and...

Mobile Tech and the Librarian: The iTest iPad Project.

Science.gov (United States)

Hamasu, Claire; Bramble, John

A 2012 project provided forty-eight health sciences librarians from primarily hospital and academic health sciences libraries with an Apple iPad2 along with training and support on its use. Project objectives were to determine how participants would adopt the iPad into their daily operations and what form of leadership role they would play while participating in the project. By project's end eighty-nine percent indicated they would continue using the iPad primarily as a productivity tool and to provide point of need services. Project data indicated that librarians assumed a leadership role promoting the use of mobile technology and the applications available.

Mobile Tech and the Librarian: The iTest iPad Project

Science.gov (United States)

Hamasu, Claire; Bramble, John

2015-01-01

A 2012 project provided forty-eight health sciences librarians from primarily hospital and academic health sciences libraries with an Apple iPad2 along with training and support on its use. Project objectives were to determine how participants would adopt the iPad into their daily operations and what form of leadership role they would play while participating in the project. By project's end eighty-nine percent indicated they would continue using the iPad primarily as a productivity tool and to provide point of need services. Project data indicated that librarians assumed a leadership role promoting the use of mobile technology and the applications available. PMID:26997921

Improving resistance of high strength concrete (HSC) bridge beams to frost and defrosting salt attack by application of hydrophobic agent

Science.gov (United States)

Kolisko, Jiri; Balík, Lukáš; Kostelecka, Michaela; Pokorný, Petr

2017-09-01

HSC (High Strength Concrete) is increasingly used for bearing bridge structures nowadays. Bridge structures in the Czech Republic are exposed to severe conditions in winter time and durability of the concrete is therefore a crucial requirement. The high strength and low water absorption of HSC suggests that the material will have high durability. However, the situation may not be so straightforward. We carried out a study of the very poor durability of HSC concrete C70/85 used to produce prestresed beams 37.1 m in length to build a 6-span highway bridge. After the beams were cast, a production control test indicated some problems with the durability of the concrete. There was a danger that 42 of the beams would not be suitable for use. All participants in the bridge project finally decided, after extensive discussions, to attempt to improve the durability of the concrete by applying a hydrophobic agent. Paper will present the results of comparative tests of four hydrophobic agents in order to choose one for real application and describes this application on construction site.

Shock absorbency of factors in the shoe/heel interaction--with special focus on role of the heel pad.

Science.gov (United States)

Jørgensen, U; Bojsen-Møller, F

1989-06-01

The heel pad acts as a shock absorber in walking and in heel-strike running. In some patients, a reduction of its shock-absorbing capacity has been connected to the development of overuse injuries. In this article, the shock absorption of the heel pad as well as external shock absorbers are studied. Individual variation and the effect of trauma and confinement on the heel pad were specifically investigated. Drop tests, imitating heel impacts, were performed on a force plate. The test specimens were cadaver heel pads (n = 10); the shoe sole component consisted of ethyl vinyl acetate (EVA) foam and Sorbothane inserts. The shock absorption was significantly greater in the heel pad than in the external shock absorbers. The mean heel pad shock absorption was 1.1 times for EVA foam and 2.1 times for Sorbothane. The shock absorption varied by as much as 100% between heel pads. Trauma caused a decrease in the heel pad shock absorbency (24%), whereas heel pad confinement increased the shock absorbency (49% in traumatized heel pads and 29.5% in nontraumatized heel pads). These findings provide a biomechanical rationale for the clinical observations of a correlation between heel pad shock absorbency loss and heel strike-dependent overuse injuries. To increase shock absorbency, confinement of the heel pad should be attempted in vivo.

Next Generation Non-particulate Dry Nonwoven Pad for Chemical Warfare Agent Decontamination

Energy Technology Data Exchange (ETDEWEB)

Ramkumar, S S; Love, A; Sata, U R; Koester, C J; Smith, W J; Keating, G A; Hobbs, L; Cox, S B; Lagna, W M; Kendall, R J

2008-05-01

New, non-particulate decontamination materials promise to reduce both military and civilian casualties by enabling individuals to decontaminate themselves and their equipment within minutes of exposure to chemical warfare agents or other toxic materials. One of the most promising new materials has been developed using a needlepunching nonwoven process to construct a novel and non-particulate composite fabric of multiple layers, including an inner layer of activated carbon fabric, which is well-suited for the decontamination of both personnel and equipment. This paper describes the development of a composite nonwoven pad and compares efficacy test results for this pad with results from testing other decontamination systems. The efficacy of the dry nonwoven fabric pad was demonstrated specifically for decontamination of the chemical warfare blister agent bis(2-chloroethyl)sulfide (H or sulfur mustard). GC/MS results indicate that the composite fabric was capable of significantly reducing the vapor hazard from mustard liquid absorbed into the nonwoven dry fabric pad. The mustard adsorption efficiency of the nonwoven pad was significantly higher than particulate activated carbon (p=0.041) and was similar to the currently fielded US military M291 kit (p=0.952). The nonwoven pad has several advantages over other materials, especially its non-particulate, yet flexible, construction. This composite fabric was also shown to be chemically compatible with potential toxic and hazardous liquids, which span a range of hydrophilic and hydrophobic chemicals, including a concentrated acid, an organic solvent and a mild oxidant, bleach.

Eco-friendly asbestos free brake-pad: Using banana peels

Directory of Open Access Journals (Sweden)

U.D. Idris

2015-07-01

Full Text Available The use of asbestos fibre is being avoided due to its carcinogenic nature that might cause health risks. A new brake pad produced using banana peel waste to replace asbestos and Phenolic resin (phenol formaldehyde, as a binder was investigated. The resin was varying from 5 to 30 wt% with an interval of 5 wt%. Morphology, physical, mechanical and wear properties of the brake pad were studied. The results show that compressive strength, hardness and specific gravity of the produced samples were seen to be increasing with an increase in wt% of resin addition, while oil soak, water soak, wear rate and percentage charred decreased as the wt% of resin increased. Overall samples, containing 25 wt% in uncarbonized banana peels (BUNCp and 30 wt% in carbonized (BCp gave better properties. The result of this research indicates that banana peel particles can be effectively used as a replacement for asbestos in brake pad manufacture.

Aspects regarding manufacturing technologies of composite materials for brake pad application

Science.gov (United States)

Craciun, A. L.; Hepuţ, T.; Pinca-Bretotean, C.

2018-01-01

Current needs in road safety, requires the development of new technical solutions for automotive braking system. Their safe operation is subject to following factors: concept design, materials used and electronic control. Among the factors previously listed, choice of materials and manufacturing processes are difficult stage but very important for achieving technical performance and getting a relatively small cost of constituting parts of brake system. The choice is based on the promotion of organic composite material, popular in areas where the weight of materials plays an important role. The brake system is composed of many different parts including brake pads, a master cylinder, wheel cylinders and a hydraulic control system. The brake pads are an important component in the braking system of automotive. These are of different types, suitable for different types of automotive and engines. Brake pads are designed for friction stability, durability, minimization of noise and vibration. The typology of the brake pads depends on the material which they are made. The aim of this paper is to presents the manufacturing technologies for ten recipes of composite material used in brake pads applications. In this work will be done: choosing the constituents of the recipes, investigation of their basic characteristics, setting the proportions of components, obtaining the composite materials in laboratory, establishing the parameters of manufacturing technology and technological analysis.

iPad-based patient briefing for radiological examinations-a clinical trial.

Science.gov (United States)

Schlechtweg, Philipp M; Hammon, Matthias; Giese, David; Heberlein, Christian; Uder, Michael; Schwab, Siegfried A

2014-08-01

To analyze if an iPad-based patient briefing can serve as a digital alternative to conventional documentations prior to radiological examinations. One hundred one patients referred for routine MRI were randomized into two groups, who underwent iPad-based and classic written briefing in opposite order. For each briefing completion time, completeness and correctness were noted. Patient's knowledge about the content of either briefing modality was subsequently tested. The influence of patient-related factors on the performance of the electronic briefing (EB) was analyzed. Finally, the patient's subjective impression of the EB was assessed. The mean durations were 4.4 ± 2.2 min for EB and 1.7 ± 1.3 min for the classic briefing (p iPad briefings were returned entirely filled out, whereas 11 % of the classic forms were returned with missing data. No significant differences in memorization of the briefing's information were objectified. There was a positive correlation between the duration of EB and age (r = 0.53; p iPads transfers the information for the patients equally well compared to the classic written approach. Although iPad briefing took patients longer to perform, the majority would prefer it to written consent briefings in the future. Nevertheless, measures have to be undertaken to improve the overall acceptance and performance.

EcoBears

DEFF Research Database (Denmark)

Nielsen, Nick; Pedersen, Sandra Bleuenn; Sørensen, Jens Ager

2015-01-01

In this paper, we introduce the EcoBears concept that aims to augment household appliances with functional and aesthetic features to promote their "use'' and "longevity of use'' to prevent their disposal. The EcoBears also aim to support the communication of environmental issues in the home setting....... We present our initial design and implementation of the EcoBears that consist of two bear modules (a mother and her cub). We also present our preliminary concept validations and lessons learned to be considered for future directions....

Versatile deprotonated NHC: C,N-bridged dinuclear iridium and rhodium complexes

Directory of Open Access Journals (Sweden)

Albert Poater

2016-01-01

Full Text Available Bearing the versatility of N-heterocyclic carbene (NHC ligands, here density functional theory (DFT calculations unravel the capacity of coordination of a deprotonated NHC ligand (pNHC to generate a doubly C2,N3-bridged dinuclear complex. Here, in particular the discussion is based on the combination of the deprotonated 1-arylimidazol (aryl = mesityl (Mes with [M(cod(μ-Cl] (M = Ir, Rh generated two geometrical isomers of complex [M(cod{µ-C3H2N2(Mes-κC2,κN3}]2. The latter two isomers display conformations head-to-head (H-H and head-to-tail (H-T of CS and C2 symmetry, respectively. The isomerization from the H-H to the H-T conformation is feasible, whereas next substitutions of the cod ligand by CO first, and PMe3 later confirm the H-T coordination as the thermodynamically preferred. It is envisaged the exchange of the metal, from iridium to rhodium, confirming here the innocence of the nature of the metal for such arrangements of the bridging ligands.

Bulk-Flow Analysis of Hybrid Thrust Bearings for Advanced Cryogenic Turbopumps

Science.gov (United States)

SanAndres, Luis

1998-01-01

increases, the bearing film thickness and flow rate decrease while the recess pressure increases. The axial stiffness coefficient shows a maximum for a certain intermediate load while the damping coefficient steadily increases. The computed results evidence the paramount of centrifugal fluid inertia at low recess pressures (i.e. low loads), and where there is actually an inflow through the bearing inner diameter, accompanied by subambient pressures just downstream of the bearing recess edge. These results are solely due to centrifugal fluid inertia and advection transport effects. Recommendations include the extension of the computer program to handle flexure pivot tilting pad hybrid bearings and the ability to calculate moment coefficients for shaft angular misalignments.

Case study: highly loaded MSE bridge supporting structure, Syncrude NMAPS conveyor overpasses

Energy Technology Data Exchange (ETDEWEB)

Scherger, B.; Brockbank, B. [Reinforced Earth Company Ltd., Edmonton, AB (Canada); Mimura, W. [Syncrude Canada Ltd., Edmonton, AB (Canada)

2005-07-01

A crusher and conveyor system was constructed at the Mildred Lake Oil Sands Mine near Fort McMurray, Alberta in order to facilitate ore delivery from Syncrude's North Mine. As part of this North Mine Auxiliary Production System (NMAPS), Syncrude Canada and their consultant Cosyn Technology identified the need for 3 overpasses over conveyors in the North Mine in order to provide unrestricted crossing over the operating conveyor system for the heavy hauler trucks and light vehicle mine traffic. The overpasses were designed to support the dead load of the granular fill and the live load of two loaded heavy hauler trucks, with a design load for each loaded hauler of 670 900 kg. This paper reviewed various aspects of the design from planning, structure selection, and overall stability and bearing capacity considerations. The different designs in the 3 new overpasses accommodated foundation and loading requirements. The designs ranged from the use of precast one-piece reinforced concrete arches, Mechanically Stabilized Earth (MSE) bridge abutment technology, and a combination of the two. The MSE retaining walls directly supported the bridge superstructure without the use of piles or other deep structural foundations. The design was challenging because of the significant vertical stresses transferred onto the wall. All 3 overpasses also used MSE walls for the supporting end wing walls. The main focus of this paper was on the heavily loaded MSE walls supporting the bridge abutment style overpasses. This structure has illustrated the capability of properly designed MSE wall structures with steel soil reinforcement and reinforced precast concrete face panels to successfully carry bridge footing pressure loadings up to 545 kPa. It was concluded that this case has good potential for use in future bridge projects in both the industrial and highway sectors. 2 refs., 7 figs.

Stable isotopes to detect food-conditioned bears and to evaluate human-bear management

Science.gov (United States)

Hopkins, John B.; Koch, Paul L.; Schwartz, Charles C.; Ferguson, Jake M.; Greenleaf, Schuyler S.; Kalinowski, Steven T.

2012-01-01

We used genetic and stable isotope analysis of hair from free-ranging black bears (Ursus americanus) in Yosemite National Park, California, USA to: 1) identify bears that consume human food, 2) estimate the diets of these bears, and 3) evaluate the Yosemite human–bear management program. Specifically, we analyzed the isotopic composition of hair from bears known a priori to be food-conditioned or non-food-conditioned and used these data to predict whether bears with an unknown management status were food-conditioned (FC) or non-food-conditioned (NFC). We used a stable isotope mixing model to estimate the proportional contribution of natural foods (plants and animals) versus human food in the diets of FC bears. We then used results from both analyses to evaluate proactive (population-level) and reactive (individual-level) human–bear management, and discussed new metrics to evaluate the overall human–bear management program in Yosemite. Our results indicated that 19 out of 145 (13%) unknown bears sampled from 2005 to 2007 were food-conditioned. The proportion of human food in the diets of known FC bears likely declined from 2001–2003 to 2005–2007, suggesting proactive management was successful in reducing the amount of human food available to bears. In contrast, reactive management was not successful in changing the management status of known FC bears to NFC bears, or in reducing the contribution of human food to the diets of FC bears. Nine known FC bears were recaptured on 14 occasions from 2001 to 2007; all bears were classified as FC during subsequent recaptures, and human–bear management did not reduce the amount of human food in the diets of FC bears. Based on our results, we suggest Yosemite continue implementing proactive human–bear management, reevaluate reactive management, and consider removing problem bears (those involved in repeated bear incidents) from the population.

Dynamic assessment of bridge deck performance considering realistic bridge-traffic interaction

Science.gov (United States)

2017-09-01

Concrete bridge decks are directly exposed to daily traffic loads and may experience some surface cracking caused by excessive stress or fatigue accumulation, which requires repair or replacement. Among typical bridges in North America, bridge decks ...

State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics.

Science.gov (United States)

Tse, Peter W; Wang, Dong

2017-02-14

Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL). Firstly, analyses of nonlinear vibration responses were conducted to construct a bearing health indicator (BHI) so as to assess the current bearing health condition. Secondly, a state space model of the BHI was developed to mathematically track the health evolution of the BHI. Thirdly, unscented particle filtering was used to predict bearing RUL. Lastly, a new bearing acceleration life testing setup was designed to collect natural bearing degradation data, which were used to validate the effectiveness of the proposed bearing prognostic method. Results show that the prediction accuracy of the proposed bearing prognostic method is promising and the proposed bearing prognostic method is able to reflect future bearing health conditions.

State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics

Directory of Open Access Journals (Sweden)

Peter W. Tse

2017-02-01

Full Text Available Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL. Firstly, analyses of nonlinear vibration responses were conducted to construct a bearing health indicator (BHI so as to assess the current bearing health condition. Secondly, a state space model of the BHI was developed to mathematically track the health evolution of the BHI. Thirdly, unscented particle filtering was used to predict bearing RUL. Lastly, a new bearing acceleration life testing setup was designed to collect natural bearing degradation data, which were used to validate the effectiveness of the proposed bearing prognostic method. Results show that the prediction accuracy of the proposed bearing prognostic method is promising and the proposed bearing prognostic method is able to reflect future bearing health conditions.

Digital representation of oil and natural gas well pad scars in southwest Wyoming: 2012 update

Science.gov (United States)

Garman, Steven L.; McBeth, Jamie L.

2015-01-01

The recent proliferation of oil and natural gas energy development in the Greater Green River Basin of southwest Wyoming has accentuated the need to understand wildlife responses to this development. The location and extent of surface disturbance that is created by oil and natural gas well pad scars are key pieces of information used to assess the effects of energy infrastructure on wildlife populations and habitat. A digital database of oil and natural gas pad scars had previously been generated from 1-meter (m) National Agriculture Imagery Program imagery (NAIP) acquired in 2009 for a 7.7-million hectare (ha) (19,026,700 acres) region of southwest Wyoming. Scars included the pad area where wellheads, pumps, and storage facilities reside and the surrounding area that was scraped and denuded of vegetation during the establishment of the pad. Scars containing tanks, compressors, the storage of oil and gas related equipment, and produced-water ponds were also collected on occasion. This report updates the digital database for the five counties of southwest Wyoming (Carbon, Lincoln, Sublette, Sweetwater, Uinta) within the Wyoming Landscape Conservation Initiative (WLCI) study area and for a limited portion of Fremont, Natrona, and Albany Counties using 2012 1-m NAIP imagery and 2012 oil and natural gas well permit information. This report adds pad scars created since 2009, and updates attributes of all pad scars using the 2012 well permit information. These attributes include the origination year of the pad scar, the number of active and inactive wells on or near each pad scar in 2012, and the overall status of the pad scar (active or inactive). The new 2012 database contains 17,404 pad scars of which 15,532 are attributed as oil and natural gas well pads. Digital data are stored as shapefiles projected to the Universal Transverse Mercator (zones 12 and 13) coordinate system. These data are available from the U.S. Geological Survey (USGS) at http://dx.doi.org/10

Ammonia formation by a thiolate-bridged diiron amide complex as a nitrogenase mimic

Science.gov (United States)

Li, Yang; Li, Ying; Wang, Baomin; Luo, Yi; Yang, Dawei; Tong, Peng; Zhao, Jinfeng; Luo, Lun; Zhou, Yuhan; Chen, Si; Cheng, Fang; Qu, Jingping

2013-04-01

Although nitrogenase enzymes routinely convert molecular nitrogen into ammonia under ambient temperature and pressure, this reaction is currently carried out industrially using the Haber-Bosch process, which requires extreme temperatures and pressures to activate dinitrogen. Biological fixation occurs through dinitrogen and reduced NxHy species at multi-iron centres of compounds bearing sulfur ligands, but it is difficult to elucidate the mechanistic details and to obtain stable model intermediate complexes for further investigation. Metal-based synthetic models have been applied to reveal partial details, although most models involve a mononuclear system. Here, we report a diiron complex bridged by a bidentate thiolate ligand that can accommodate HN=NH. Following reductions and protonations, HN=NH is converted to NH3 through pivotal intermediate complexes bridged by N2H3- and NH2- species. Notably, the final ammonia release was effected with water as the proton source. Density functional theory calculations were carried out, and a pathway of biological nitrogen fixation is proposed.

iPad colour vision apps for dyschromatopsia screening.

Science.gov (United States)

Campbell, Thomas Gordon; Lehn, Alexander; Blum, Stefan; Airey, Caroline; Brown, Helen

2016-07-01

Optic neuritis (ON) is a common and important cause of vision loss or vision disturbances in the community, particularly amongst the young, and it is often associated with a persistent dyschromatopsia. Traditionally screening for dyschromatopsia has been carried out using pseudo-isochromatic Ishihara plates. These colour plates were originally developed for testing of colour blindness, and indeed have only more recently been applied to ON. As the Ishihara plate books used for testing are expensive, unwieldy, and are not commonly available in many clinics or wards, many neurologists and ophthalmologists have taken to using untested and unstudied downloadable software packages on portable electronic devices for testing. This study compared the efficacy of printed and iPad (Apple, Cupertino, CA, USA) versions of the Ishihara plates in screening for dyschromatopsia in patients who were suspected of having ON. The main finding was that dyschromatopsia testing using a commercially available application on an iPad was comparable to using the current pragmatic clinical benchmark, the pseudo-isochromatic plates of Ishihara. These findings provide support for the increasingly common practice of screening for dyschromatopsia using the iPad. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparing performance on the MNREAD iPad application with the MNREAD acuity chart.

Science.gov (United States)

Calabrèse, Aurélie; To, Long; He, Yingchen; Berkholtz, Elizabeth; Rafian, Paymon; Legge, Gordon E

2018-01-01

Our purpose was to compare reading performance measured with the MNREAD Acuity Chart and an iPad application (app) version of the same test for both normally sighted and low-vision participants. Our methods included 165 participants with normal vision and 43 participants with low vision tested on the standard printed MNREAD and on the iPad app version of the test. Maximum Reading Speed, Critical Print Size, Reading Acuity, and Reading Accessibility Index were compared using linear mixed-effects models to identify any potential differences in test performance between the printed chart and the iPad app. Our results showed the following: For normal vision, chart and iPad yield similar estimates of Critical Print Size and Reading Acuity. The iPad provides significantly slower estimates of Maximum Reading Speed than the chart, with a greater difference for faster readers. The difference was on average 3% at 100 words per minute (wpm), 6% at 150 wpm, 9% at 200 wpm, and 12% at 250 wpm. For low vision, Maximum Reading Speed, Reading Accessibility Index, and Critical Print Size are equivalent on the iPad and chart. Only the Reading Acuity is significantly smaller (I. E., better) when measured on the digital version of the test, but by only 0.03 logMAR (p = 0.013). Our conclusions were that, overall, MNREAD parameters measured with the printed chart and the iPad app are very similar. The difference found in Maximum Reading Speed for the normally sighted participants can be explained by differences in the method for timing the reading trials.

Diagnostic procedure on brake pad assembly based on Young's modulus estimation

International Nuclear Information System (INIS)

Chiariotti, P; Santolini, C; Tomasini, E P; Martarelli, M

2013-01-01

Quality control of brake pads is an important issue, since the pad is a key component of the braking system. Typical damage of a brake pad assembly is the pad–backing plate detachment that affects and modifies the mechanical properties of the whole system. The most sensitive parameter to the damage is the effective Young's modulus, since the damage induces a decrease of the pad assembly stiffness and therefore of its effective Young's modulus: indeed its variation could be used for diagnostic purposes. The effective Young's modulus can be estimated from the first bending resonance frequency identified from the frequency response function measured on the pad assembly. Two kinds of excitation methods, i.e. conventional impulse excitation and magnetic actuation, will be presented and two different measurement sensors, e.g. laser Doppler vibrometer and microphone, analyzed. The robustness of the effective Young's modulus as a diagnostic feature will be demonstrated in comparison to the first bending resonance frequency, which is more sensitive to geometrical dimensions. Variability in the sample dimension, in fact, will induce a variation of the resonance frequency which could be mistaken for damage. The diagnostic approach has been applied to a set of undamaged and damaged pad assemblies showing good performance in terms of damage identification. The environmental temperature can be an important interfering input for the diagnostic procedure, since it influences the effective Young's modulus of the assembly. For that reason, a test at different temperatures in the range between 15 °C and 30 °C has been performed, evidencing that damage identification technique is efficient at any temperature. The robustness of the Young's modulus as a diagnostic feature with respect to damping is also presented. (paper)

Cable Supported Bridges

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...... to quantify the different structural configurations and allows a preliminary optimization of the main structure.Included are the most recent advances in structural design, corrosion protection of cables, aerodynamic safety, and erection procedures....

Office for iPad and Mac for dummies

CERN Document Server

Weverka, Peter

2015-01-01

The easy way to work with Office on your iPad or Mac Are you a Mac user who isn't accustomed to working with Microsoft Office? Consider this friendly guide your go-to reference! Written in plain English and packed with easy-to-follow, step-by-step instructions, Office for iPad and Mac For Dummies walks you through every facet of Office, from installing the software and opening files to working with Word, Excel, PowerPoint, and Outlook-and beyond. Plus, you'll discover how to manage files, share content and collaborate online through social media, and find help when you need it. Two things a

Comparison of Alignment Correction Angles Between Fixed-Bearing and Mobile-Bearing UKA.

Science.gov (United States)

Inoue, Atsuo; Arai, Yuji; Nakagawa, Shuji; Inoue, Hiroaki; Yamazoe, Shoichi; Kubo, Toshikazu

2016-01-01

Good outcomes have been reported with both fixed-bearing and mobile-bearing unicompartmental knee arthroplasty (UKA). However, overcorrected alignment could induce the progression of arthritis on the non-arthroplasty side. Changes of limb alignment after UKA with both types of bearings (fixed bearing: 24 knees, mobile bearing: 28 knees) were investigated. The mean difference between the preoperative standing femoral-tibial angle (FTA) and postoperative standing FTA was significantly larger in mobile bearing UKA group. In fixed-bearing UKA, there must be some laxity in MCL tension so that a 2-mm tension gauge can be inserted. In mobile-bearing UKA, appropriate MCL tension is needed to prevent bearing dislocation. This difference in MCL tension may have caused the difference in the correction angle between the groups. Copyright © 2016 Elsevier Inc. All rights reserved.

Design of a digital PAD based on I/Q demodulation principle

International Nuclear Information System (INIS)

Geng Zheqiao; Cui Yanyan; Hou Mi; Pei Guoxi

2005-01-01

Conventional analog I/Q demodulator suffers from phase and amplitude imbalance and DC offset, which cause big error into the measurement. A digital PAD is designed. Based on I/Q demodulation principle, using digital algorithms, such as digital filter and Hilbert transform, the conventional measurement error can basically be removed. Measuremental results show that the digital PAD has a maximum phase error of ±0.5 degree and a resolution of 0.2 degree. Its temperature coefficient is -0.1 degree/degree C. Its dynamic ranges for phase-measurement and amplitude-measurement are -1825 dBm and -2020 dBm, respectively. The digital PAD can meet the need of the BEPC II phasing system. (authors)

Study on Load-displacement Test of Rubber Pads of Coal Mine Roadway Constructed by Shield

Science.gov (United States)

Yang, Yue; Chen, Xiaoguo; Yang, Liyun

2017-12-01

Shield method construction of coal mine roadway is the future trend of the development of deep coal mining. The main shaft supporting is the segment. There is rubber pads between segment and segment. The performance of compression deformation of rubber pad is essential for the overall stability of lining. Through load test, displacement of the rubber pad under load, the thrust force law of the rubber pad deformation, and provide a theoretical basis for the stability analysis of coal mine tunnel shield construction.

Bridge Programs in Illinois: Results of the 2010 Illinois Bridge Status Survey

Science.gov (United States)

Taylor, J. L.; Harmon, T.

2010-01-01

This report provides a summary of major results of the Illinois Bridge Status Survey, administered online between April and June 2010. The purpose of the survey was to understand the extent to which bridge programs are being implemented in Illinois, as well as to build an online directory of bridge programs. Bridge programs are an emerging…

Field performance of timber bridges. 6, Hoffman Run stress-laminated deck bridge

Science.gov (United States)

M. A. Ritter; P. D. Hilbrich Lee; G. J. Porter

The Hoffman Run bridge, located just outside Dahoga, Pennsylvania, was constructed in October 1990. The bridge is a simple-span, single-lane, stress-laminated deck superstructure that is approximately 26 ft long and 16 ft wide. It is the second stress-laminated timber bridge to be constructed of hardwood lumber in Pennsylvania. The performance of the bridge was...

Bringing back the bridge solution to establish a fixed link over the Strait of Gibraltar

International Nuclear Information System (INIS)

Diaz Simal, P.

2015-01-01

The aim of this essay is to address some of the aspects of the Bridge alternative and to examine the conclusions reached back in 1995 over the feasibility of such a solution. Although having been left aside for decades, the Bridge Solution of the Strait of Gibraltar Crossing Project has been brought back to life as an available alternative to close the gap between the two continents, being the reason to have recently detected some impediment down into the lower layers of the site laying grounds. All of which has revealed further geotechnical issues to tackle. Given the current level of development the Tunnel solution has reached, the 20-year-old Bridge solution needs to be fully updated in order to catch up with the former: As well as taking into consideration the new trends present in the state of the art on design of structures, the Bridge solution would also entail updating construction procedures if it is to incorporate all the potentialities offered by: (1) related tools (2) machinery, and (3), many new ideas which, coming from distinct industrial sectors others than the public works, have worked their way through the construction field. Furthermore, it would be necessary to bear in mind the ceaseless development materials science is going through, which involves constant increases in both levels of resilience and number of characteristics such materials present. (Author)

Does It Matter Whether One Takes a Test on an iPad or a Desktop Computer?

Science.gov (United States)

Ling, Guangming

2016-01-01

To investigate possible iPad related mode effect, we tested 403 8th graders in Indiana, Maryland, and New Jersey under three mode conditions through random assignment: a desktop computer, an iPad alone, and an iPad with an external keyboard. All students had used an iPad or computer for six months or longer. The 2-hour test included reading, math,…

Examining Teachers' Use of iPads: Comfort Level, Perception, and Use

Science.gov (United States)

Liu, Min; Navarrete, Cesar C.; Scordino, Robert; Kang, Jina; Ko, Yujung; Lim, Mihyun

2016-01-01

While there is evidence of the growing popularity of iPads and other tablets in K-12 education, little is understood about how teachers use these devices in their instruction. This study examines 342 teachers' comfort level with and perception toward iPad use and any changes that occurred over the implementation year. Using a mixed-methods design,…

Rancang Bangun Modul PAD (Packet Assembler Dissassembler Menggunakan AX.25 pada Sistem Komunikasi ITS-SAT

Directory of Open Access Journals (Sweden)

Pasang Arung Padang

2013-09-01

Full Text Available ITS-Sat merupakan jenis satelit piko yang saat ini sedang dikembangkan di Institut Teknologi Sepuluh Nopember. ITS-Sat membutuhkan suatu protokol komunikasi yang mengatur tata cara komunikasi satelit. Protokol AX.25 merupakan protokol komunikasi yang digunakan dalam sistem komunikasi ITS-Sat. Protokol ini berada pada layer data link dalam model OSI Layer. Protokol ini dapat membangun dan memutuskan link serta melakukan pengiriman data. Protokol AX.25 menggabungkan data-data field menjadi suatu frame. Makalah ini mengimplementasikan protokol AX.25 ke dalam modul PAD (Packet Assembler Dissassembler. Protokol AX.25 diimplementasikan ke dalam mikrokontroler yang merupakan otak dari modul PAD dengan menggunakan bahasa pemograman. Modul PAD berfungsi untuk mengkapsulasi data tiap field menjadi sebuah frame AX.25 sebelum dikirim dan kemudian frame AX.25 yang diterima dienkapsulasi kembali menjadi data field. Modul PAD yang dibuat dapat mengirim dan menerima data teks sebanyak 500 karakter. Hasil pengujian menunjukan bahwa modul PAD yang dibuat mampu melakukan komunikasi antar modul PAD dengan baik.