bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of tendon plating to manage failed calcaneal tendon repairs in a dog
Authors: Zellner Eric M. , Hale Michael J. , Kraus Karl H. 
Published: February 2018

AbstractObjectiveTo report the application of a plate to treat a complicated calcaneal tendon rupture and the resulting outcome.Study DesignClinical case report.AnimalsA 3‐year‐old Labrador retriever.MethodsA 3‐year‐old Labrador retriever was treated for a partially ruptured calcaneal tendon. Two primary tendon repairs with sutures and external fixation had failed. A veterinary cuttable plate was placed to internally span the tendon over the primary repair. The external fixation that had been previously placed was maintained, and the dog was placed in a non–weight‐bearing sling for 3 weeks after surgery. Adjunct therapy included an injection of platelet‐rich plasma in the tendon and laser therapy. The external fixator was removed 4 weeks postoperatively, and the plate was removed 8 weeks postoperatively.ResultsA mature fibrous union bridged the site of anastomosis 8 weeks after surgery. The owners reported normal activity 6 months after surgery and symmetric hock angles and musculature 2 years after surgery.ConclusionAdjunct plating of previously failed calcaneal tendon repairs in a dog resulted in an excellent long‐term outcome.Clinical SignificancePlating tendons can be considered as an additional method that may improve tendon apposition and decrease gap formation.
Umbilical cannulation optimizes circuit flows in premature lambs supported by the EXTra‐uterine Environment for Neonatal Development (EXTEND)
Authors: Hornick Matthew A. , Davey Marcus G. , Partridge Emily A. , Mejaddam Ali Y. , McGovern Patrick E. , Olive Aliza M. , Hwang Grace , Kim Jenny , Castillo Orlando , Young Kathleen , Han Jiancheng , Zhao Sheng , Connelly James T. , Dysart Kevin C. , Rychik Jack , Peranteau William H. , Flake Alan W. 
Published: February 2018

Key points
Bronchopulmonary dysplasia is a disease of extreme prematurity that occurs when the immature lung is exposed to gas ventilation.
We designed a novel ‘artificial womb’ system for supporting extreme premature lambs (called EXTEND) that obviates gas ventilation by providing oxygen via a pumpless arteriovenous circuit with the lamb submerged in sterile artificial amniotic fluid.
In the present study, we compare different arteriovenous cannulation strategies on EXTEND, including carotid artery/jugular vein (CA/JV), carotid artery/umbilical vein (CA/UV) and umbilical artery/umbilical vein (UA/UV).
Compared to CA/JV and CA/UV cannulation, UA/UV cannulation provided significantly higher, physiological blood flows to the oxygenator, minimized flow interruptions and supported significantly longer circuit runs (up to 4 weeks).
Physiological circuit blood flow in UA/UV lambs made possible normal levels of oxygen delivery, which is a critical step toward the clinical application of artificial womb technology.
AbstractEXTEND (EXTra‐uterine Environment for Neonatal Development) is a novel system that promotes physiological development by maintaining the premature lamb in a sterile fluid environment and providing gas exchange via a pumpless arteriovenous oxygenator circuit. During the development of EXTEND, different cannulation strategies evolved with the aim of improving circuit flow. The present study examines how different cannulation strategies affect EXTEND circuit haemodynamics in extreme premature lambs. Seventeen premature lambs were cannulated at gestational ages 105–117 days (term 145–150 days) and supported on EXTEND for up to 4 weeks. Experimental groups were distinguished by cannulation strategy: carotid artery outflow and jugular vein inflow (CA/JV; n = 4), carotid artery outflow and umbilical vein inflow (CA/UV; n = 5) and double umbilical artery outflow and umbilical vein inflow (UA/UV; n = 8). Circuit flows and pressures were measured continuously. As we transitioned from CA/JV to CA/UV to UA/UV cannulation, mean duration of circuit run and weight‐adjusted circuit flows increased (P < 0.001) and the frequency of flow interruptions declined (P < 0.05). Umbilical vessels generally accommodated larger‐bore cannulas, and cannula calibre was directly correlated with circuit pressures and indirectly correlated with flow:pressure ratio (a measure of post‐membrane resistance). We conclude that UA/UV cannulation in fetal lambs on EXTEND optimizes circuit flow dynamics and flow stability and also supports circuit flows that closely approximate normal placental flow.
Flow and Heat Transfer Analysis of Mist-Film Cooling on a Flat Plate
Authors: Dwivedi Anjali , Verma Ankit , Sarkar S. 
Published: February 2018

Film cooling is one of the preferred methods for effective cooling of a gas turbine that forms a protective layer between hot flue gases and blade surface. This paper investigates the interaction of mist in the secondary flow and physics indicating the upper limit of mist concentration. Numerical simulations are performed on a flat plate having a series of discrete holes with 35 degree streamwise orientation and the holes are connected to a common delivery plenum chamber. The blowing ratio, density ratio and Reynolds number based on freestream and hole diameter (D) are 0.5, 1.2 and 15885 respectively. A two-phase mist consisting of finely dispersed water droplets of 10 micron in an airstream is introduced as the coolant from these holes. The latent heat absorbed by the evaporating droplets significantly reduces the sensible heat of the main stream, providing heat sinks that result in enhanced cooling effectiveness. The coupling between the two-phases is modelled through the interaction terms in the transport equations. Computations are performed by ANSYS Fluent 15.0 using k-ε realizable model.
The results illustrate insight of complex transport phenomena associated with the mist of varying concentration from 2% to 7%. It has been observed that the maximum enhancement of cooling effectiveness reaches 43% at X/D = 10 for 2% mist by mass with an average enhancement of 26.5%. For 3% mist, the maximum enhancement becomes 80% at X/D = 16 with the average cooling enhancement of 43%. Mist concentrations 5% and beyond trend to increase average cooling because of more absorption of latent heat by droplets, but its trajectories shift towards wall, detrimental to the blade due to corrosion effect and thermal stresses.
Force Estimation in Electromagnetic System Using Augmented Kalman Filter
Authors: Redekar Rahul Vijaykumar , Kumar Gaurav , Kalita Karuna , Tammi Kari 
Published: February 2018

The analytical modelling and real time estimation of electromagnetic forces brings many challenges and in many situations, it is very difficult to develop an accurate model of force production. The present work describes an estimation of the actual forces generated by an electromagnetic actuator based on augmented Kalman filter.
A cantilever beam with end concentrated mass has been chosen as a vibrating system and an E–shaped laminated core with coils on the middle limb has been chosen as the electromagnetic exciter. The available analytical formulation has been chosen for the calculation of the generated forces which have been corrected using augmented Kalman filter.
The developed experimental setup has a mild steel beam of 150 mm length with a mass of 560 g at its tip and an E shaped lamination core with a stack thickness of 38 mm.
Parametric Studies of Vortex Generators Using Source Term Modelling
Authors: Kumar Kanneri Thettiyepath Arun , Madsen Jesper , Piragalathalwar Sudhakar , Narayana Aswatha 
Published: February 2018

The Vortex Generators located over the airfoils are generally small in size. Due to its small size and shape, the mesh requirements are high and mesh generation becomes complex. In this study, the source term modelling approach termed as BAY model developed by Bender et al. is used to simulate the effect of Vortex Generators. One of the advantages of BAY model is its simplicity eliminating the complex grid requirements around the Vortex Generator for the Computational Fluid Dynamic simulations. Comparing with the BAY model approach, mesh resolved Vortex Generator approach will need more number of cells in the domain. Hence using the B AY model is advantageous in computational cost also.
The solver EllipSys3D, which is an incompressible structured multi-block finite volume based RANS (Reynolds Averaged Navier-Stokes) solver, is used for the studies. Parametric studies using BAY model are carried out for different heights, lengths, chord wise locations and spacing of Vortex Generators on a wind turbine airfoil. The qualitative results predicted using BAY model are in lined with experimental results from literature showing that it is capable to mimic the effect of Vortex Generators. So overall due to its simplicity source term modelling through BAY model can be used for quick parametric studies.
A Comparison of Two Reduced Order Methods for Probabilistic Mistuning Investigations
Authors: Waldherr Christian U. , Vogt Damian M. 
Published: February 2018

Slight variances in the manufacturing of rotating machinery can lead to significant changes in the structural dynamic behavior compared to the behavior of ideal cyclic periodic structures. Therefore it is necessary to consider deviations from the perfect cyclic periodic structures in the mechanical design process of rotating machinery. To minimize the effort of numerical calculations, the application of reduced order models is indispensable.
The objective of this paper is the comparison of two reduction methods which are not widespread in application of rotationally periodic structures. For the validation of the implemented methods, a generic model of a thin plate meshed with shell elements and a representative large size FE model of a radial turbine wheel are used. The first reduction method is called Improved Reduced System and is based on the classical Guyan reduction. The second reduction method is called SEREP method and is from a theoretical point of view closely related to the first method although the procedure to obtain the reduction basis is quite different. The results show for both test cases an excellent agreement between the reduced order models and the unreduced finite element model. Both reduction methods are also able to capture the phenomena of mode localization. It is also found that through the application of the reduced order methods the computation time can be reduced by two orders of magnitude. Based on the first reduction method, the statistical mistuning behavior is studied using the accelerated Monte Carlo simulation.
A Comparison of Different Mesh Topology for Numerical Analysis of a Turbulent Liquid Jet
Authors: Sonawane Rohitkumar , Kumar Vivek , Nakod Pravin 
Published: February 2018

Gas turbine engine combustors widely employ injection of liquid fuel in cross flow air as a fuel atomization process. Fuel atomization has a major impact on the efficiency, exit profile and emissions of the combustors. Since the quality of spray directly affects the performance of the combustors, it is important to understand a complex phenomenon of spray formation involving trajectory evolution, surface breakup, column fracture and dispersion of secondary droplets. There are several ways of analyzing spray formation which include experimental measurements, numerical analysis using Direct Numerical Simulation (DNS), a combination of output from Volume of Fluid (VOF) and empirical correlations or a hybrid Eulerian-Lagrangian multiscale method. In any of the numerical methods used for the analysis of the sprays, the mesh topology and resolution have a great impact on the accuracy of the predictions.
In the present work, evaluation of mesh topology particularly hexahedral and polyhedral meshes, is carried out to understand their effect on the accuracy of the spray prediction and explore the possibility of employing the polyhedral mesh for such a complex phenomenon. The mesh generation for polyhedral meshes is comparatively easier than hexahedral meshes and it has better control on the growth of the element size, resulting in lesser mesh count. A hybrid Eulerian-Lagrangian multiscale method developed earlier is used along with scale resolving turbulence model (Large Eddy Simulation) in this work. The test case considered for the analysis is taken from the experimental analysis done by Gopala et al. [2]. Momentum flux ratio of 10 and weber number of 1500 are selected for the present analysis. Simulation results from both the mesh topologies are compared with the experimental results for quantities like jet penetration length, Sauter mean diameter and droplet velocity profiles at different z/d locations. It is observed that both the mesh topologies considered, perform equally well and therefore, polyhedral mesh topology can be employed successfully for hybrid spray modeling.
A Study on the Nonlinear Dynamic Characteristics of Gas Turbine Engine Components
Authors: Murty Pilli Narayana , Kasina Lakshman , Bommisetty Kondaiah , Karri Sreenivas , Raghavan Kotur Srinivasan 
Published: February 2018

Rotating as well as static components of aero engines such as rotors and casings must be capable of withstanding vibrations which arises from various engine order excitations. HCF is attributed as one of the major failures due to its high crack propagation rate. The tolerances to vibration have become a key point to avoid resonance in operating range. Analytical predictions of individual components gives better accuracy and good agreement with test data. However, when the components are assembled, the accuracy of analyses can considerably depreciate since models describing stiffness and friction properties of joints are linearized. In such conditions proper predictions of dynamic response becomes difficult and may lead to under prediction or over prediction of dynamic response.
A nonlinear analysis is required to study the influence of joints flexibility on dynamic response. In this paper different nonlinear joint models are investigated to assess the dynamic behavior of the contact interface in terms of slipping and sticking contact parameters. The study shows significant changes over dynamic characteristics when compared to linear analysis. From this study, it is evident that nonlinear behavior of the contact in dynamic analysis phase due to slip and separation plays vital role over the dynamic characteristics of the component. This study emphasizes to consider physical behavior of joints in dynamic analysis to avoid catastrophic HCF failures.
Prediction of Soot Formation Trends in Turbulent Kerosene-Air Diffusion Jet Flames With Elevated Operating Pressure
Authors: Nakod Pravin , Patwardhan Saurabh , Verma Ishan , Orsino Stefano 
Published: February 2018

Emission standard agencies are coming up with more stringent regulations on soot, given its adverse effect on human health. It is expected that Environmental Protection Agency (EPA) will soon place stricter regulations on allowed levels of the size of soot particles from aircraft jet engines. Since, aircraft engines operate at varying operating pressure, temperature and air-fuel ratios, soot fraction changes from condition to condition. Computation Fluid Dynamics (CFD) simulations are playing a key role in understanding the complex mechanism of soot formation and the factors affecting it.
In the present work, soot formation prediction from numerical analyses for turbulent kerosene-air diffusion jet flames at five different operating pressures in the range of 1 atm. to 7 atm. is presented. The geometrical and test conditions are obtained from Young’s thesis [1]. Coupled combustion-soot simulations are performed for all the flames using steady diffusion flamelet model for combustion and Mass-Brookes-Hall 2-equation model for soot with a 2D axisymmetric mesh. Combustion-Soot coupling is required to consider the effect of soot-radiation interaction. Simulation results in the form of axial and radial profiles of temperature, mixture fraction and soot volume fraction are compared with the corresponding experimental measured profiles. The results for temperature and mixture fraction compare well with the experimental profiles. Predicted order of magnitude and the profiles of the soot volume fraction also compare well with the experimental results. The correct trend of increasing the peak soot volume fraction with increasing the operating pressure is also captured.
A Study on Performance of Aero-Engine With Fluidic Thrust Vector Nozzle
Authors: Xiao-bo Zhang , Zhan-xue Wang , Jing-wei Shi 
Published: February 2018

Shock Vector Controlling (SVC) nozzle is one of the most effective ways to obtain the thrust vector for the advanced engine. The SVC nozzle has the advantages of simple structure, light weight and fast response. Numerous analytical, numerical and experimental studies have been carried out on SVC nozzle in recent years. While these studies mainly focus on the nozzle and ignore the influence between SVC nozzle and engine. In fact, the secondary flows of fluidic thrust vectoring nozzle are all extracted from the engine fan or high pressure compressor, no matter it is based on SVC or others. The extraction and injection of the secondary flow both influence the components matching and engine performance. And the mass flow and pressure of secondary flow are constrained by engine working condition in turn. So the SVC nozzle should be installed in the engine environment for evaluation.
The influence of SVC nozzle secondary flow on engine thermodynamic cycle and performance is in two major ways. First, when the secondary flow extracts from the fan or HPC, the operating point of the engine will change. It results in the thermodynamic parameters at each engine stations and the performance of engine change. The reason for this change is that the bleeding of secondary flow broke the mass flow balance equations between the engine components. Second, the injection of secondary flow in the expansion section of nozzle also leads to engine performance change, while the engine operating point remains normal.
The characteristic of certain SVC nozzle is obtained by computational fluid dynamics method. Then the Response Surface Method (RSM) model based on the design of experiment is employed to build the relations of performance parameters and design variables of SVC nozzle. Combining basic engine performance simulation model with SVC nozzle RSM model, the model for engine with SVC nozzle is built. To evaluate the performance of the engine with SVC nozzle, the conceptual design of double bypass variable cycle engine with SVC nozzle is given. The influence of the secondary flow extracting from the fan outlet, CDFS outlet and the first stage of HPC is discussed. And its performances such as vector angle, thrust coefficient, thrust and specific fuel consumption are obtained by employing the engine simulation model built by this paper.
Necessity of Kinematic Strain Hardening in Simulating Impact Events
Authors: Kirloskar Sharang , Singh Gurmeet , Kumar Avinash 
Published: February 2018

Impact events are very high speed and short duration events. Experimental analysis of such events tends to be extremely expensive and challenging to study because of the apparatus and measurement systems required to capture the event. Due to this, impact events are studied extensively through simulations. The ability to simulate these events is a dictating factor for developing better and more efficient designs.
Traditionally, loads occurring due to impact events are assumed to monotonically increase and hence pure isotropic strain hardening is sufficient to model the material behavior. However, this assumption doesn’t hold true for all impact events. When the loads caused by an impact do not monotonically increase but instead oscillate causing tension and compression cycles, pure isotropic hardening could lead to unrealistic results.
In this work, different strain hardening rules are studied and analyzed for a plate under impact loading. The process to obtain a parameter which sets a realistic combination of isotropic and kinematic strain hardening rules is demonstrated and discussed. Limitations of the existing practice of using isotropic hardening in impact loading cases are studied. An alternative approach to accommodate the kinematic hardening rule into material models using LS-DYNA, a finite element solver, is discussed.
Antifungal Susceptibility of the Aspergillus viridinutans Complex: Comparison of Two
In Vitro
Methods
Authors: Lyskova Pavlina , Hubka Vit , Svobodova Lucie , Barrs Vanessa , Dhand Navneet K. , Yaguchi Takashi , Matsuzawa Tetsuhiro , Horie Yoshikazu , Kolarik Miroslav , Dobias Radim , Hamal Petr 
Published: February 2018

ABSTRACT

Cryptic species of
Aspergillus fumigatus
, including the
Aspergillus viridinutans
species complex, are increasingly reported to be causes of invasive aspergillosis. Their identification is clinically relevant, as these species frequently have intrinsic resistance to common antifungals. We evaluated the susceptibilities of 90 environmental and clinical isolates from the
A. viridinutans
species complex, identified by DNA sequencing of the calmodulin gene, to seven antifungals (voriconazole, posaconazole, itraconazole, amphotericin B, anidulafungin, micafungin, and caspofungin) using the reference European Committee on Antimicrobial Susceptibility Testing (EUCAST) method. The majority of species demonstrated elevated MICs of voriconazole (geometric mean [GM] MIC, 4.46 mg/liter) and itraconazole (GM MIC, 9.85 mg/liter) and had variable susceptibility to amphotericin B (GM MIC, 2.5 mg/liter). Overall, the MICs of posaconazole and the minimum effective concentrations of echinocandins were low. The results obtained by the EUCAST method were compared with the results obtained with Sensititre YeastOne (YO) panels. Overall, there was 67% agreement (95% confidence interval [CI], 62 to 72%) between the results obtained by the EUCAST method and those obtained with YO panels when the results were read at 48 h and 82% agreement (95% CI, 78 to 86%) when the results were read at 72 h. There was a significant difference in agreement between antifungals; agreement was high for amphotericin B, voriconazole, and posaconazole (70 to 86% at 48 h and 88 to 93% at 72 h) but was very low for itraconazole (37% at 48 h and 57% at 72 h). The agreement was also variable between species, with the maximum agreement being observed for
A. felis
isolates (85 and 93% at 48 and 72 h, respectively). Elevated MICs of voriconazole and itraconazole were cross-correlated, but there was no correlation between the other azoles tested.