bluuebunny/crossref_metadata_2025 huggingface dataset:
The Control of Non-Axisymmetric Flow in Axial Turbomachinery Using Circumferentially Varying Stator Exit Angles
Authors: Taylor Jonathan , Hynes Tom
Published: August 2014

Turbomachinery operating in distorted flowfields is often very close to the sources of the distortion, and can influence the flowfield distortions at its inlet and outlet. Several techniques are available to reduce the impact of an upstream-running outlet distortion on the turbomachinery by introducing circumferential variation in the most downstream stator row. However, these techniques assume that the upstream-running distortion is not changed by the modifications to the turbomachinery, and none of them addresses the issue of inlet distortion, either on its own or in combination with outlet distortion.

A methodology to design circumferentially varying stator angles has been developed. This is based on a two-dimensional linearisation of the distorted flow through the turbomachinery, combined with information from three-dimensional flowfield calculations. The resulting new design method has been applied to an installed lift fan operating with considerable inlet and outlet distortion.

The distorted flow through the lift fan is computed by a three-dimensional numerical method incorporating an actuator disc blade row model. The new design method is then used to produce several redesigned builds with circumferentially varying stator exit angles. The three-dimensional flow through the new builds is computed, and compared with flow through the axisymmetric fan.

The calculations show that existing non-axisymmetric design strategies may not be applicable to installations having large flowfield distortions. An alternative approach based on unsteady rotor loading is presented, and relatively small stator exit angle variations are shown to produce significant reductions in this quantity.
Analysis of the Inter-Row Flow Field Within a Transonic Axial Compressor: Part 1 — Experimental Investigation
Authors: Ottavy Xavier , Trébinjac Isabelle , Vouillarmet André
Published: August 2014

This paper relates to 2D-laser two-focus anemometry measurements, conducted in a transonic research high pressure compressor. Curved glass, which conforms to the shroud contour, was used. The resulting optical distortions of the control volume were corrected using an original and inexpensive optical assembly. Synchronized measurements were performed on two surfaces of the IGV-rotor inter-row region. Particular care was taken in evaluating the capabilities of our L2F technique to accurately describe a flow field with strong gradient. The results presented show that the flow field is dominated by the moving oblique shock and its interaction with the IGV wake.
A Three-Dimensional Viscous Transonic Inverse Design Method
Authors: Tiow W. T. , Zangeneh M.
Published: August 2014

The development and application of a three-dimensional inverse methodology is presented for the design of turbomachinery blades. The method is based on the mass-averaged swirl, rV~θ distribution and computes the necessary blade changes directly from the discrepancies between the target and initial distributions. The flow solution and blade modification converge simultaneously giving the final blade geometry and the corresponding steady state flow solution.

The flow analysis is performed using a cell-vertex finite volume time-marching algorithm employing the multistage Runge-Kutta integrator in conjunction with accelerating techniques (local time stepping and grid sequencing). To account for viscous effects, dissipative forces are included in the Euler solver using the log-law and mixing length models. The design method can be used with any existing solver solving the same flow equations without any modifications to the blade surface wall boundary condition.

Validation of the method has been carried out using a transonic annular turbine nozzle and NASA rotor 67. Finally, the method is demonstrated on the re-design of the blades.
Optimization of Interblade Friction Damper Design
Authors: Panning Lars , Sextro Walter , Popp Karl
Published: August 2014

The vibration amplitudes of bladed disk assemblies can be reduced significantly by means of friction damping devices such as shrouds, damping wires and interblade friction dampers. In practice, interblade friction dampers are applied in rotating arrangements with various geometries showing curved or flat surfaces like so-called wedge-shaped dampers. This paper is focusing on a computation method to predict the dynamical behaviour of turbine blades with friction dampers including both, curved and wedge-shaped dampers with Hertzian and non-Hertzian contact conditions, respectively. The presented computation method uses a 3D contact model to calculate the contact forces, including normal and tangential stiffnesses, roughness and microslip effects. The relative displacements in the contact area can be expressed by means of 6 DOF of the blade platforms and 6 rigid body DOF of the damper including translational and rotational displacements. The relative displacement of the friction damper with respect to the adjacent blades can be derived from the contact kinematics of the blade-damper-blade system and the equations of motion of the friction damper. Thus, the model can be applied to investigate spatial motions of the bladed disk assembly including bending and torsional vibrations. A comparison of different friction damper designs with respect to an optimal damper geometry and damper mass is presented. The advantages and disadvantages of each design will be discussed. Experimental results are shown to validate the developed computation method.
Status of the Multi-Annular Swirl Burner at the Power Systems Development Facility
Authors: Brushwood John , Foote John , Morton Frank , Wallace Larry
Published: August 2014

The Power Systems Development Facility (PSDF) is an engineering scale demonstration of two advanced coal-fired power systems and several high-temperature, high-pressure gas filtration systems. The PSDF was designed at sufficient scale so that advanced power systems and components could be tested in an integrated fashion to provide data for commercial scale-up. The PSDF is funded by the U.S. Department of Energy, Electric Power Research Institute, Southern Company Services, Foster Wheeler, Kellogg Brown & Root, Siemens Westinghouse Power Corporation (SWPC), Combustion Power Company and Peabody Holding Company.

The PSDF is configured into two separate test trains: the Kellogg Brown & Root (KBR) transport reactor train and the Foster Wheeler Advanced Pressurized Fluidized Bed Combustor (APFBC) train. The APFBC train also includes a topping combustor and gas turbine generator to produce electrical power. The APFBC train is designed for long term testing of the filtration systems and the assessment of control and integration issues associated with the APFBC system.

The Siemens Westinghouse Multi-Annular Swirl Burner (MASB) has been developed as the topping combustor for the APFBC application. In this application, the combustion air is vitiated air, a depleted oxygen (10 to 16 vol %), high temperature (1200 to 1400°F) (650 to 760°C) gas stream, which is the exhaust gas from the fluidized bed combustion of solid fuel. The topping combustor fuel is a synthetic low-Btu fuel gas at high temperature (1200 to 1400°F) (650 to 760°C) generated by gasifying coal in the APFBC. The hot MASB combusted gas is expanded through a gas turbine for power generation.

Commissioning of the MASB began in January, 1998. Over 400 hours of operation have been accumulated through November 1999. Several improvements have been designed and installed during commissioning. This paper explains the design basis of the MASB, describes design changes implemented at the PSDF and reviews the operational experience of the MASB at the PSDF.
Tubular Solid Oxide Fuel Cell/Gas Turbine Hybrid Cycle Power Systems — Status
Authors: Veyo Stephen E. , Shockling Larry A. , Dederer Jeffrey T. , Gillett James E. , Lundberg Wayne L.
Published: August 2014

The solid oxide fuel cell (SOFC) is a simple electrochemical device that operates at 1000°C, and is capable of converting the chemical energy in natural gas fuel to AC electric power at approximately 45% efficiency (net AC/LHV) when operating in a system at atmospheric pressure. Since the SOFC exhaust gas has a temperature of approximately 850°C, the SOFC generator can be synergistically integrated with a gas turbine (GT) engine-generator by supplanting the turbine combustor and pressurizing the SOFC, thereby enabling the generation of electricity at efficiencies approaching 60% or more. Conceptual design studies have been performed for SOFC/GT power systems employing a number of the small recuperated gas turbine engines that are now entering the marketplace. The first hardware embodiment of a pressurized SOFC/GT power system has been built for Southern California Edison and is scheduled for factory acceptance tests beginning in Fall, 1999 at the Siemens Westinghouse facilities in Pittsburgh, Pennsylvania. The hybrid power cycle, the physical attributes of the hybrid systems, and their performance are presented and discussed.
Influence of the Artificial Dissipation Model on the Propagation of Acoustic and Entropy Waves
Authors: Corral Roque , Burgos Manuel Antonio , García Antonio
Published: August 2014

The aim of this work is to show that the form of the artificial dissipation terms used in central-difference-type schemes to stabilise the solution of the unsteady Euler equations may play a crucial role on the propagation of entropy, vorticity and acoustic waves. It will be demonstrated by means of numerical experiments and theoretical analysis that the scalar formulation of the artificial viscosity prevents the correct propagation of entropy and vorticity waves for moderate low Mach numbers and that the upstream propagation of acoustic waves degrades significantly for high subsonic flows. It will be proved that if the scaling of the dissipative terms takes into account the fact that the entropy and acoustic waves may propagate at quite different velocities, the accuracy of the scheme is greatly improved. Actually it will be demonstrated that there exists a class of problems for which the standard scheme is unable to produce equivalent solutions to the ones obtained by the matricial model, without a large penalty in the number of points.
Elasto Plastic Stress Analysis of LP Steam Turbine Blades Under Centrifugal Loading
Authors: Rao J. S. , Ramakrishnan C. V. , Gupta K. , Singh A. K.
Published: August 2014

The low pressure last stage blades in a steam turbine are some of the most severely stressed machine elements under centrifugal loading. The stresses in the root region near a strain raiser are in the plastic range. The conventional analysis is based on elastic theories and any stresses found beyond the ultimate tensile strength in a small zone are ignored. In this paper an elasto-plastic analysis of a last stage low-pressure steam turbine blade is made by considering a finite element model of the blade with the root alone and also by including the disk effect. The results obtained by EMRC NISA finite element package are presented. The material is shown to yield in a small zone confined to a fraction of an elemental depth near the notch point of the root and in the vicinity of the ultimate tensile strength of the material.
On Flowfield Periodicity in the NASA Transonic Flutter Cascade: Part I — Experimental Study
Authors: Lepicovsky J. , McFarland E. R. , Chima R. V. , Wood J. R.
Published: August 2014

An extensive study to improve flow uniformity and periodicity in the NASA Transonic Flutter Cascade is presented here. The results are reported in two independent parts dealing with the experimental approach and the analytical approach. The first part, the Experimental Study, focuses first on the data sets acquired in this facility in the past and explains several discrepancies, particularly the questions of actual flow incidence and cascade backpressure levels. Next, available means for control and modifications of the cascade flowfield, boundary layer bleed and tailboard settings are presented in detail. This is followed by experimental data sets acquired in modified test facility configurations that were based on analytical predictions of the cascade flowfield. Finally, several important conclusions about improving the cascade flowfield uniformity and blade load periodicity are summarized. The most important conclusions are: (1) boundary layer bleed system does not improve the cascade flow periodicity; (2) carefully match the tunnel wall contours to the expected shape of cascade streamlines; (3) measure actual flow incidence for each cascade configuration rather than rely on the tunnel geometry; and (4) the current cascade configuration exhibits a very high blade load uniformity over six blades from blade #2 to blade #7, and the facility is now ready for unsteady pressure data acquisition.
Measurements in Film Cooling With Lateral Injection: Adiabatic Effectiveness Values and Temperature Fields
Authors: Oke Rohit A. , Simon Terrence W.
Published: August 2014

Temperature fields were taken in a film cooling lateral injection configuration with pitch-to-hole-diameter of 3.0. These measurements were done with a traversing thermocouple. Momentum flux ratios of 0.25, 1.0 and 2.25 were used. Results are presented as fields of dimensionless temperatures, given by θ=Tprobe-T∞Tc-T∞. Near-surface values of this quantity over an unheated surface are adiabatic effectiveness values. Streamwise evolutions of these temperature fields are documented. It is seen how with higher blowing ratio the film cooling jets tend to lift off the surface. Comparisons are made to previous data and computational results. It is verified that lateral injection yields a more uniform distribution of effectiveness immediately downstream of injection. It is shown also how interaction of adjacent film cooling jets leads to such improved uniformity. This interaction depends on the pitch to diameter ratio, P/D. In order to study the effect of this parameter, additional data with P/D = 6.0 are presented. The present thermal field data complement previous velocity field measurements taken in the same flow.
Turbomachinery Selection Processes for Pipeline Service Revised and Updated Through Incorporation of Lessons Learned
Authors: Cleveland A. , Humphries E.
Published: August 2014

In 1975 two companies were competing for the opportunity to design and build a major pipeline system to carry natural gas from the North Slope of Alaska and the Beaufort Delta to markets in Canada and the USA.
Disc Design and Air System Comparison Between a Single and a Two Stage High Pressure Turbine Aero Engine
Authors: Ahmad Fathi , Mirzamoghadam Alexander V.
Published: August 2014

The design of the high pressure turbine (HPT) module of an aero engine and the method used to predict disc life and burst margin are different among the manufactures. In this paper, two different disc design methods are presented and compared, namely, the strain instability and the Chambers methods. The results of the disc study show that the strain instability method introduces low disc weight compared to the Chambers method. Both methods satisfy the burst speed requirement of 125% of the red line limit speed.

The strain instability method was applied to design the disc of a single stage (SS) and of a two stage (TS) HPT configuration. The design philosophy of the SS is to run the HPT with a high rpm and a low SOT, whereas the TS design is based on low rpm and high SOT. The disc preliminary design considered the mechanical boundary conditions only without a temperature gradient. The total boundary conditions (thermal and mechanical) were then applied to the detailed disc design.

A comparison between the two applied air systems of the SS and the TS design configuration was also performed. In comparing the two, the SS presents a design with low cooling air consumption, and it is also found that a cover plate is necessary for the front side of the SS configuration. The results of this study could be useful for the design engineer to know how and what is needed to accomplish a safe and effective design. Complementary thermal and structural tests should be performed to identify the limits and benefits of each approach.
Experimental Investigations of Tip Clearance Flow and its Influence on Secondary Flows in a 1-1/2 Stage Axial Turbine
Authors: Stephan B. , Gallus H. E. , Niehuis R.
Published: August 2014

A multistage turbomachine has inherently unsteady flow fields due to the relative motion between rotor and stator airfoils, which lead to viscous and inviscid interactions between the blade rows. Additionally, the radial clearance between casing and rotor strongly influences the 3D flow field and the loss generation in turbomachines. The objective of the presented study is to investigate the effects of tip clearance on secondary flow phenomena and, in consequence, on the performance of a 1-1/2 stage axial turbine. The low aspect ratio of the blades and their prismatic design leads to a high degree of secondary flows and three-dimensionality. Extended measurements of the flow field behind each blade row with pneumatic and hotwire probes have been conducted for three different tip clearances. Experimental results reveal significant change of flow behavior and turbine performance with increasing tip clearance.
Evaluation of 1700C Class Turbine Blades in Hydrogen Fueled Combustion Turbine System
Authors: Okamura Takanari , Koga Akinori , Itoh Shoko , Kawagishi Hiroyuki
Published: August 2014

This paper describes the cooling design and experimental evaluations of the 1700C class turbine blades in hydrogen fueled combustion turbine system. The hybrid cooling method combining recovery steam cooling with partial film cooling was chosen based on a careful study on several cooling systems from the viewpoint of plant efficiency and durability of turbine blades. In the development process, high temperature cooled turbine blades, the advanced cooling technologies, single crystal super alloy and thermal barrier coating (TBC) are important issues to be paid attention and following experiments were performed. First, outer heat transfer test on stator blade and internal heat transfer test in ribbed channel for cooling rotor blade were carried out using liquid crystal thermography. The cooling effectiveness of rotor blade was further investigated in steam driven wind tunnel. The characteristics of single crystal super alloy and TBC were also evaluated in hot steam environment. As a next step, the scale model test blades of size nearly one half to that of the first stage stator and rotor blades in actual turbine were designed and manufactured. Finally, the turbine blade cascade tests were conducted using hydrogen-oxygen combustion driven wind tunnel under practical hot steam conditions of 1700C and 2.5MPa. In these experiments, cooling effectiveness, metal temperatures and cooling steam flow characteristics were investigated. After completing all the test runs, the robustness of blade substrate and TBC were inspected. The experimental results on the hybrid cooling method and blade design procedures are discussed.
Design, Analysis, Fabrication and Test of an Aspirated Fan Stage
Authors: Schuler Brian J. , Kerrebrock Jack L. , Merchant Ali A. , Drela Mark , Adamczyk John
Published: August 2014

A fan stage designed by means of a MISES-based quasi-3D approach (Youngren and Drela, 1991), for a pressure ratio of 1.6 at a tip Mach number of 0.7, has been analyzed by viscous 3D CFD, fabricated and tested in the MIT Blowdown Compressor. The design incorporates a rotor tip shroud and boundary layer removal on the suction surfaces of the rotor and stator and at other critical locations. The fully viscous 3D analysis enabled final detailing of the design. In tests, the stage has met its design objectives, producing the design pressure ratio of 1.6 at design speed. The mass flow removed totaled 4.7%, approximately 1.0% through slots on the suction surface of the rotor and stator, and the remainder distributed over the rotor shroud and stator hub. The measured adiabatic efficiency of the rotor for the throughflow was 96% at the design point and that for the stage was 90%. This paper presents the design, the results of the analysis and the experimental stage performance both at design and at some off-design conditions.
Aerodynamic Design and Analysis of a High Pressure Ratio Aspirated Compressor Stage
Authors: Merchant Ali A. , Drela Mark , Kerrebrock Jack L. , Adamczyk John J. , Celestina Mark
Published: August 2014

The pressure ratio of axial compressor stages can be significantly increased by controlling the development of blade and endwall boundary layers in regions of adverse pressure gradient by means of boundary layer suction. This concept is validated and demonstrated through the design and analysis of a unique aspirated compressor stage which achieves a total pressure ratio of 3.5 at a tip speed of 1500 ft/s. The aspirated stage was designed using an axisymmetric through-flow code coupled with a quasi three-dimensional cascade plane code with inverse design capability. Validation of the completed design was carried out with three-dimensional Navier-Stokes calculations. Spanwise slots were used on the rotor and stator suction surfaces to bleed the boundary layer with a total suction requirement of 4% of the inlet mass flow. Additional bleed of 3% was also required on the hub and shroud near shock impingement locations. A three-dimensional viscous evaluation of the design showed good agreement with the quasi three-dimensional design intent, except in the endwall regions. The three-dimensional viscous analysis predicted a mass averaged total pressure ratio of 3.7 at an isentropic efficiency of 93% for the rotor, and a mass averaged total pressure ratio of 3.4 at an isentropic efficiency of 86% for the stage.
Computational Modeling of Low-Pressure Fan Flows
Authors: Thakur Siddharth , Lin Wanlai , Wright Jeffrey , Shyy Wei , Lievens Ron
Published: August 2014

A CFD-based computational tool is used to analyze flows in axial fans. Computed results for an axial fan flow field for one particular blade shape are presented; certain global quantities such as the mass-averaged pressure rise and the static efficiency available from test data for different mass flow rates are used to evaluate the trends predicted by the CFD results. The characteristic feature of the fan flow fields presented here is a very low pressure rise; due care is exercised to ensure that grid dependence and numerical dissipation do not smear out the key features of the computed flow fields.
Analysis of the Mixing Plane Interface Between Stator and Rotor of a Transonic Axial Turbine Stage
Authors: Giangiacomo P. , Michelassi V. , Martelli F.
Published: August 2014

A three-dimensional transonic turbine stage is computed by means of a numerical simulation tool. The simulation accounts for the coolant ejection from the stator blade and for the tip leakage of the rotor blade. The stator and rotor rows interact via a mixing plane, which allows the stage to be computed in a steady manner. The analysis is focused on the matching of the stator and rotor mass flow rates. The computations proved that the mixing plane approach allows the stator and rotor mass flow rates to be balanced with a careful choice of the stator-rotor static pressure interface. At the same time, the pitch averaged distribution of the transported quantities at the interface for the stator and rotor may differ slightly, together with the value of the static pressure at the hub.
Effect of Swirl on the Performance of a Gas Turbine Reversing Exhaust Duct
Authors: Cunningham M. H. , Birk A. M. , Gauthier J. E. D. , Di Bartolomeo W.
Published: August 2014

Poor pressure recovery and flow control in gas turbine exhaust ducts can significantly reduce overall engine performance. For aircraft installations, a configuration that presents a challenging design is the single port tractor exhaust that is used where the turbine is facing the direction of travel. This duct consists of an annular to rectangular transition and a turn of approximately 160°. The combination of a diffusing duct with strong curvature produces a flow that has a non-uniform velocity profile throughout the duct, large areas of separation and strong vortices. These flow conditions lead to insufficient diffusion and large pressure losses, making the design of a low loss duct difficult. The problem of design is further complicated by the need for the duct to operate over a range of flow Mach number and swirl angles.

An experimental study has been undertaken to identify the main flow structures that lead to poor performance in tractor exhausts and how the key geometric and flow parameters affect the flow. A half scale model of the exhaust duct has been tested using cold flow over a range of swirl conditions. Flow measurements include static wall pressures, and inlet and outlet velocity profiles.

This paper presents experimental results showing the effects of swirl on a gas turbine single port tractor exhaust duct.
Experimental and Computational Investigation of Losses in a Circular to Oblong Diffusing Gas Turbine Transition Duct With Offset
Authors: Stronach A. J. , Birk A. M.
Published: August 2014

The installation of a gas turbine engine onto an aircraft often necessitates the use of complicated ducting for the inlet and exhaust from the engine nacelle. These ducts may involve shape transitions as well as significant redirection of the flow. The optimization of these ducts may reduce the performance losses typically incurred with inlet and exhaust ducting. This study examines the aerodynamic and performance characteristics of a specific duct geometry that is a combination of a transition duct and an s-shaped duct. The study is motivated by aircraft gas turbine exhaust design considerations including lower engine back pressure, reduced wing sooting, and the reduction of thermal fatigue issues with aircraft structures. Experimental and computational (CFD) techniques were used to investigate the internal flow structure and distortion losses. Swirl was introduced to determine the sensitivity of the duct to the rotating flow typical of a gas turbine. Cold flow testing was performed for a scale model of the duct and compared with results from a commercial 3D CFD code. Velocity profiles were well predicated but loses were underpredicted by the RNG-kε turbulence model. The study has shown the value of CFD for the prediction of general performance trends in the design of a practical engineering device.
Compressor Stability Enhancement Using Discrete Tip Injection
Authors: Suder Kenneth L. , Hathaway Michael D. , Thorp Scott A. , Strazisar Anthony J. , Bright Michelle B.
Published: August 2014

Mass injection upstream of the tip of a high-speed axial compressor rotor is a stability enhancement approach known to be effective in suppressing stall in tip-critical rotors. This process is examined in a transonic axial compressor rotor through experiments and time-average Navier-Stokes CFD simulations. Measurements and simulations for discrete injection are presented for a range of injection rates and distributions of injectors around the annulus.

The simulations indicate that tip injection increases stability by unloading the rotor tip and that increasing injection velocity improves the effectiveness of tip injection. For the tested rotor, experimental results demonstrate that at 70% speed the stalling flow coefficient can be reduced by 30% using an injected massflow equivalent to 1% of the annulus flow. At design speed, the stalling flow coefficient was reduced by 6% using an injected massflow equivalent to 2% of the annulus flow. The experiments show that stability enhancement is related to the mass-averaged axial velocity at the tip. For a given injected massflow, the mass averaged axial velocity at the tip is increased by injecting flow over discrete portions of the circumference as opposed to full-annular injection. The implications of these results on the design of recirculating casing treatments and other methods to enhance stability will be discussed.
The NASA Aviation Safety Program: Overview
Authors: Shin Jaiwon
Published: August 2014

In 1997, the United States set a national goal to reduce the fatal accident rate for aviation by 80% within ten years based on the recommendations by the Presidential Commission on Aviation Safety and Security. Achieving this goal will require the combined efforts of government, industry, and academia in the areas of technology research and development, implementation, and operations. To respond to the national goal, the National Aeronautics and Space Administration (NASA) has developed a program that will focus resources over a five year period on performing research and developing technologies that will enable improvements in many areas of aviation safety. The NASA Aviation Safety Program (AvSP) is organized into six research areas: Aviation System Modeling and Monitoring, System Wide Accident Prevention, Single Aircraft Accident Prevention, Weather Accident Prevention, Accident Mitigation, and Synthetic Vision. Specific project areas include Turbulence Detection and Mitigation, Aviation Weather Information, Weather Information Communications, Propulsion Systems Health Management, Control Upset Management, Human Error Modeling, Maintenance Human Factors, Fire Prevention, and Synthetic Vision Systems for Commercial, Business, and General Aviation aircraft. Research will be performed at all four NASA aeronautics centers and will be closely coordinated with Federal Aviation Administration (FAA) and other government agencies, industry, academia, as well as the aviation user community. This paper provides an overview of the NASA Aviation Safety Program goals, structure, and integration with the rest of the aviation community.
Technical Note: Millimeter precision in ultrasound based patient positioning: Experimental quantification of inherent technical limitations
Authors: Ballhausen Hendrik , Hieber Sheila , Li Minglun , Belka Claus , Reiner Michael
Published: August 2014

Purpose:

To identify the relevant technical sources of error of a system based on three‐dimensional ultrasound (3D US) for patient positioning in external beam radiotherapy. To quantify these sources of error in a controlled laboratory setting. To estimate the resulting end‐to‐end geometric precision of the intramodality protocol.

Methods:

Two identical free‐hand 3D US systems at both the planning‐CT and the treatment room were calibrated to the laboratory frame of reference. Every step of the calibration chain was repeated multiple times to estimate its contribution to overall systematic and random error. Optimal margins were computed given the identified and quantified systematic and random errors.

Results:

In descending order of magnitude, the identified and quantified sources of error were: alignment of calibration phantom to laser marks 0.78 mm, alignment of lasers in treatment vs planning room 0.51 mm, calibration and tracking of 3D US probe 0.49 mm, alignment of stereoscopic infrared camera to calibration phantom 0.03 mm. Under ideal laboratory conditions, these errors are expected to limit ultrasound‐based positioning to an accuracy of 1.05 mm radially.

Conclusions:

The investigated 3D ultrasound system achieves an intramodal accuracy of about 1 mm radially in a controlled laboratory setting. The identified systematic and random errors require an optimal clinical tumor volume to planning target volume margin of about 3 mm. These inherent technical limitations do not prevent clinical use, including hypofractionation or stereotactic body radiation therapy.
Weight Lifted and Countermovement Potentiation of Power in the Concentric Phase of Unstable and Traditional Resistance Exercises
Authors: Zemková Erika , Jeleň Michal , Kovác̆iková Zuzana , Ollé Gábor , Vilman Tomáš , Hamar Dušan
Published: August 2014

The study evaluates the effect of weight lifted on power in the concentric phase of resistance exercises on stable and unstable surfaces. A group of 19 fit men performed randomly on different days 3 reps of (a) barbell chest presses on the bench and Swiss ball, and (b) barbell squats on stable base and BOSU ball. Exercises were performed without and with countermovement (CM) using maximal effort in concentric phase. Initial weight of 20 kg was increased by 10 kg or 5 kg (at higher loads) up to at least 85% of previously established 1RM under stable conditions. Results showed no significant differences in mean power in the concentric phase of stable and unstable CM chest presses at lower weights lifted (from 20 to 50 kg). However, its values were significantly higher during chest presses on the bench than on Swiss ball while lifting higher weights (from 60 to 90 kg). Similarly, mean power in the concentric phase of squats was significantly higher on stable base than on BOSU ball at higher weights lifted (from 60 to 90 kg). Though a set of data showed significant differences, the effect sizes ≤ 0.7 suggest no practically meaningful differences. It may be concluded that unstable base compromises the power in the concentric phase of resistance exercises, however, only at higher weights lifted.
Can Technique Modification Training Reduce Knee Moments in a Landing Task?
Authors: Dempsey Alasdair R. , Elliott Bruce C. , Munro Bridget J. , Steele Julie R. , Lloyd David G.
Published: August 2014

Anterior cruciate ligament (ACL) injuries are costly. Sidestep technique training reduces knee moments that load the ACL. This study examined whether landing technique training alters knee moments. Nineteen team sport athletes completed the study. Motion analysis and ground reaction forces were recorded before and after 6 weeks of technique modification. An inverse dynamic model was used to calculate three-dimensional knee loading. Pre- and postintervention scores were compared using paired t tests. Maximal knee flexion angle during landing was increased following training. There was no change in valgus or flexion moments, but an increase in peak internal rotation moment. This increase in internal rotation moment may increase the risk of ACL injury. However, the increased angle at which the peak internal rotation moment occurred at follow up may mitigate any increase in injury risk by reducing load transmission.
Do Qualitative Changes in Interlimb Coordination Lead to Effectiveness of Aquatic Locomotion Rather Than Efficiency?
Authors: Komar John , Sanders Ross H. , Chollet Didier , Seifert Ludovic
Published: August 2014

This study compared interlimb coordination and indicators of swim efficiency and effectiveness between expert and recreational breaststroke swimmers. Arm-leg coordination of 8 expert and 10 recreational swimmers at two different paces, slow and sprint, were compared using relative phase between elbow and knee. For each participant, knee and elbow angles were assessed using a 3-dimensional video analysis system with four below and two above cameras. During each phase of the cycle, indicators of swim efficiency (intracyclic velocity variations) and effectiveness (horizontal distance, velocity peaks, acceleration peaks) were calculated. Two coordination patterns emerged between expert and recreational swimmers, with significant differences in the relative phase at the beginning of a cycle (−172.4° for experts and −106.6° for recreational swimmers) and the maximum value of relative phase (9.1° for experts and 45.9° for recreational swimmers; all P < .05). Experts’ coordination was associated with higher swim effectiveness (higher acceleration peak: 2.4 m/s2 for experts and 1.6 m/s2 for recreational swimmers) and higher distance covered by the center of mass during each phase of the cycle (all P < .05). This study emphasized how experts coordinate arms and legs to achieve effective behavior, therefore exhibiting flexibility, mainly in the timing of the glide phase, to adapt to different speed.
Joint Contribution to Fingertip Movement During a Number Entry Task: An Application of Jacobian Matrix
Authors: Qin Jin , Trudeau Matthieu , Buchholz Bryan , Katz Jeffrey N. , Xu Xu , Dennerlein Jack T.
Published: August 2014

Upper extremity kinematics during keyboard use is associated with musculoskeletal health among computer users; however, specific kinematics patterns are unclear. This study aimed to determine the dynamic roles of the shoulder, elbow, wrist and metacarpophalangeal (MCP) joints during a number entry task. Six subjects typed in phone numbers using their right index finger on a stand-alone numeric keypad. The contribution of each joint of the upper extremity to the fingertip movement during the task was calculated from the joint angle trajectory and the Jacobian matrix of a nine-degree-of-freedom kinematic representation of the finger, hand, forearm and upper arm. The results indicated that in the vertical direction where the greatest fingertip movement occurred, the MCP, wrist, elbow (including forearm) and shoulder joint contributed 10.2%, 55.6%, 27.7% and 6.5%, respectively, to the downward motion of the index finger averaged across subjects. The results demonstrated that the wrist and elbow contribute the most to the fingertip vertical movement, indicating that they play a major role in the keying motion and have a dynamic load beyond maintaining posture.
Consistency of Peak and Mean Concentric and Eccentric Force Using a Novel Squat Testing Device
Authors: Stock Matt S. , Luera Micheal J.
Published: August 2014

The ability to examine force curves from multiple-joint assessments combines many of the benefits of dynamic constant external resistance exercise and isokinetic dynamometry. The purpose of this investigation was to examine test-retest reliability statistics for peak and mean force using the Exerbotics eSQ during maximal concentric and eccentric squats. Seventeen resistance-trained men (mean ± SD age = 21 ± 2 years) visited the laboratory on two occasions. For each trial, the subjects performed two maximal concentric and eccentric squats, and the muscle actions with the highest force values were analyzed. There were no mean differences between the trials (P > .05), and the effect sizes were < 0.12. When the entire force curve was examined, the intraclass correlation coefficients (model 2,1) and standard errors of measurement, respectively, were concentric peak force = 0.743 (8.8%); concentric mean force = 0.804 (6.0%); eccentric peak force = 0.696 (10.6%); eccentric mean force = 0.736 (9.6%). These findings indicated moderate-to-high reliability for the peak and mean force values obtained from the Exerbotics eSQ during maximal squat testing. The analysis of force curves from multiple-joint testing provides researchers and practitioners with a reliable means of assessing performance, especially during concentric muscle actions.
Draft Genome Sequence of a Symbiotic Bacterium, Rhizobium vignae CCBAU 05176T
Authors: Liu Yang , Yi Zhiwei , Zeng Runying
Published: August 2014

TheRhizobium vignaestrain CCBAU 05176Twas isolated from a root nodule ofAstragalus dahuricusgrown in Hebei Province, China. It grows on yeast mannitol agar (YMA) supplemented with 0 to 2% (wt/vol) NaCl. We report the annotated genome sequence of this strain in a 6.34-Mb scaffold.
Draft Genomes of Three Strains Representative of the Bacillus anthracis Diversity Found in France
Authors: Girault Guillaume , Parisot Nicolas , Peyretaillade Eric , Peyret Pierre , Derzelle Sylviane
Published: August 2014

We report here the draft genomes of three
Bacillus anthracis
strains isolated in France: 08-8_20 (A.Br.001/002), 99-100 (A.Br.011/009), and 00-82 (B.Br CNEVA). The total lengths of assemblies are 5,440,708 bp, 5,446,472 bp, and 5,436,014 bp for 08-8_20, 99-100, and 00-82, respectively.
Sports-related concussion increases the risk of subsequent injury by about 50% in elite male football players
Authors: Nordström Anna , Nordström Peter , Ekstrand Jan
Published: August 2014

Background

Little is known about the short-term and long-term sequelae of concussion, and about when athletes who have sustained such injuries can safely return to play.

Purpose

To examine whether sports-related concussion increases the risk of subsequent injury in elite male football players.

Study design

Prospective cohort study.

Methods

Injuries were registered for 46 male elite football teams in 10 European countries in the 2001/2002–2011/2102 seasons. Two survival models were used to analyse whether concussion increased the subsequent risk of an injury in the first year.

Results

During the follow-up period, 66 players sustained concussions and 1599 players sustained other injuries. Compared with the risk following other injuries, concussion was associated with a progressively increased risk of a subsequent injury in the first year (0 to <3 months, HR=1.56, 95% CI 1.09 to 2.23; 3 to <6 months, HR=2.78, 95% CI 1.58 to 4.89; 6–12 months, HR=4.07, 95% CI 2.14 to 7.76). In the second model, after adjustment for the number of injuries in the year preceding the concussion, this injury remained significantly associated with the risk of subsequent injury in the first year (HR=1.47, 95% CI 1.05 to 2.05).

Conclusions

Concussion was a risk factor for sustaining subsequent injury within the following year. In-depth medical evaluation, which includes neurological and cognitive assessment, is warranted within the concussion management and return-to- play process.
To see or not to see: a qualitative interview study of patients’ views on their own diagnostic images
Authors: Carlin Leslie E , Smith Helen E , Henwood Flis
Published: August 2014

Objectives

To ascertain what meaning individuals attach to perceiving images of their own interior body and how the images and their meanings affect the clinical consultation.

Design

Face-to-face semistructured interviews.

Participants

25 adult patients in southern England who, within the preceding 12 months, had been referred for diagnostic imaging.

Setting

Community.

Results

For patients, being shown their own X-rays, MRIs or CT images creates a variety of effects: (1) a sense of better understanding of the diagnosis; (2) validation of their sensory and emotional response to the illness or injury and (3) an alteration to the tenor and nature of the clinical encounter between patient and physician. In addition to meanings attached to these images, patients also impute meaning to the physician's decisionnotto share an image with them. The desire to see their image was greater in those patients with a skeletal injury; patients are less keen on viewing abdominal or other soft tissue images.

Conclusions

Viewing images of one's interior, invisible body is powerful and resonant in a number of ways. The experience of not seeing, whether through the patient's or the physician's choice, is also fraught with meaning.
Investigating the organisational impacts of quality improvement: a protocol for a realist evaluation of improvement approaches drawing on the Resource Based View of the Firm
Authors: Burton Christopher R , Rycroft Malone Jo , Robert Glenn , Willson Alan , Hopkins Angela
Published: August 2014

Introduction

Little is understood about the role of quality improvement in enabling health organisations to survive and thrive in the contemporary context of financial and economic challenges. We will draw on the theoretical foundations of the ‘Resource Based View of the Firm’ (RBV) to develop insights into why health organisations engage in improvement work, how impacts are conceptualised, and ‘what works’ in delivering these impacts. Specifically, RBV theorises that the mix and use of resources across different organisations may explain differences in performance. Whether improvement work influences these resources is unclear.

Methods and analysis

Case study research will be conducted across health organisations participating in four approaches to improvement, including: a national improvement programme; a multiorganisational partnership around implementation; an organisational strategy for quality improvement; and a coproduction project designed to enhance the experience of a clinical service from the perspective of patients. Data will comprise in-depth interviews with key informants, observation of key events and documents; analysed within and then across cases. Adopting a realist perspective, the core tenets of RBV will be evaluated as a programme theory, focusing on the interplay between organisational conditions and behavioural or resource responses that are reported through engagement in improvement.

Ethics and dissemination

The study has been approved by Bangor University Ethics Committee. The investigation will not judge the relative merits of different approaches to healthcare quality improvement. Rather, we will develop unique insights into the organisational consequences, and dependencies of quality improvement, providing an opportunity to add to the explanatory potential of RBV in this and other contexts. In addition to scientific and lay reports of the study findings, research outputs will include a framework for constructing the economic impacts of quality improvement and practical guidance for health service managers that maximises the impacts of investment in quality improvement.
Minimally invasive endoscopic staging for mediastinal lymphadenopathy in lung cancer: a systematic review protocol
Authors: Liu Hong , Zhou Jie , Feng Qiao-ling , Wan Gang , Xie Yong-jun , Gu Hai-tao
Published: August 2014

Introduction

Minimally invasive endoscopic biopsy techniques have been widely available as potential alternatives for mediastinal lesions staging in patients with known or suspected lung cancer. Previous efforts have been made to evaluate the diagnostic performance of specific endoscopic modality alone at the level of the mediastinum for staging lung cancer, however, few studies focus on the accuracy of comparisons between different endoscopic modalities, especially at the level of any individual lymph node station. The objective of our study is to determine the diagnostic yields of different endoscopic modalities for staging mediastinal lymphadenopathy in lung cancer, especially concerning the individual lymph node station.

Methods/design

A systematic electronic search of MEDLINE, EMBASE, SinoMed and ISI Web of Science were performed to identify studies evaluating endoscopic modalities accuracy with restriction of English and Chinese languages from inception to an update until May 2014. Data were extracted with the patient as the unit of analysis with regards to the abilities of different endoscopic modalities at the level of mediastinum and particular lymph node station. The methodological quality was assessed independently according to the Quality Assessment of Diagnostic Accuracy Study (QADAS) criteria. An exact binomial rendition of bivariate mixed-effects regression model was used to estimate the pooled sensitivity and specificity. Also, pre–post probability analysis, publication bias analysis and sensitivity analysis were performed for a synthesis of knowledge of this context.

Dissemination

The findings will advance our better available knowledge of optimal clinical decision-making when dealing with staging of mediastinal metastasis in lung cancer.

Trial registration number

PROSPERO—NIHR Prospective Register of Systematic Reviews (CRD42014009792).