bluuebunny/crossref_metadata_2025 huggingface dataset:
A Hydraulic Design Procedure of Axial-Flow Pump
Authors: Shen Zhenhua , Rasmussen Svend , Ma Xiaofen , Jacobsen Christian Brix
Published: July 2018

A radical decrease of the product development time has been achieved by implementation of simulation driven development on axial-flow pump design. A new automatic hydraulic design procedure of axial-flow pumps was developed. It consists of in-house developed parametric design template, Visual Basic macro, OpenFOAM and an in-house developed pump performance plot tool. In this procedure the parametric template includes propeller design and guide vane design. A mesh is generated by using OpenFOAM snappyHexMesh utility. Visual Basic macro is used to link the parametric template and OpenFOAM.

In order to validate the accuracy of predicting the hydraulic performance from this procedure, a high specific speed axial-flow pump was designed by using this procedure and an in-house optimization tool. Finally an aluminum scaled prototype was made by CNC machining. The CFD results show that BEP efficiency is equal to 83.5%, and testing shown BEP efficiency of 85%. It indicates that the hydraulic design from this procedure is both reliable and able to produce high efficiency designs.
Investigation on Rotor-Stator Interaction in a Low Specific Speed Centrifugal Pump
Authors: Zhang Ning , Yang Minguan , Gao Bo , Li Zhong , Ni Dan
Published: July 2018

In centrifugal pump, due to intense rotor-stator interaction, high amplitude pressure pulsating would be induced, and it has a crucial influence on the stable operating of the pump. In this paper, a low specific speed centrifugal pump is investigated to illustrate unsteady flow within the centrifugal pump. Pressure pulsation signals are attained by mounting 20 monitoring points along the spiral volute, covering all the interested region of the model pump. FFT (Fast Fourier Transform algorithm) is applied to analyze the time-domain pressure signals.

Results show that in pressure spectra, evident peaks at blade passing frequency fBPF together with its high harmonics can be identified, and the amplitudes are closely associated with operating conditions of the model pump and the positions of the monitoring points. At nominal flow rate, four vortical regions with high amplitude are captured inside the model pump. And the unsteady vortical structure at the near tongue region is related to the relative position of the impeller with respect to the tongue, and the upstream effect of the volute tongue significantly affects the vorticity distribution on the blade pressure side.

At off-design conditions, the interaction pattern between the vortical structure and the volute tongue is significantly affected compared with that at the rated condition, as to the upstream effect of the tongue. At high flow rate, partial vortex would separate from the main vortex, but at low flow rate, the cutting and impingement effects of the tongue are much weaker due to almost all the vortex moving to the narrow side of the tongue.

Based on the analysis of rotor-stator interaction in the model pump, some conclusions could be obtained. Pressure amplitudes at fBPF are associated with the positions of monitoring points and operating conditions of the model pump. Vorticity magnitude at blade exit increases as the impeller passes the volute tongue. And the fluid-dynamic blade-volute interaction is dominated by the vorticity shedding from blade trailing edge and their impingement on the volute tongue with subsequent cutting and distortion. And high pressure amplitude is generated with the corresponding high vorticity magnitude observed. So the intense interaction between flow structures (jet-wake pattern) and volute tongue is crucial to unsteady pressure pulsation. Thus, to lower pressure pulsation amplitude and fluid dynamic forces, controlling the vortical structure at blade trailing edge is an effective method.
A New Method EWT-Based for Rolling Element Bearing Weak Fault Diagnosis
Authors: Jiang Xingxing , Li Shunming , Cheng Chun , Li Aijuan
Published: July 2018

The collected vibration signals from defective rolling element bearings are generally non-stationary and corrupted by strong background noise. The weak fault feature extraction is crucial to mechanical fault diagnosis and machine condition monitoring. A new method EWT-based (Empirical Wavelet Transform) for bearing fault diagnosis is proposed in this paper. It consists of four parts. Firstly, the frequency ranges of meaningful modes are self-adaptively obtained by combining scale-space representation and Otsu’s method. Secondly, the meaningful modes are acquired by utilizing EWT to decompose the raw vibration signal. Thirdly, the first two modes possessing maximum kurtosis are selected as fault components. Lastly, the fault-related features could be observed in the time domain and envelope spectra of the selected modes. Experimental results verify that the proposed method is very effective for bearing weak fault diagnosis and the performance of proposed method is obviously better than the method of empirical mode decomposition (EMD).
Thermo-Mechanical Analysis of Mixed-Mode Damage: Cohesive Zone Modeling
Authors: Altammar Hussain , Kaul Sudhir , Dhingra Anoop
Published: July 2018

Damage detection and diagnostics is a key area of research in structural analysis. This paper presents results from the analysis of mixed-mode damage initiation in a composite beam under thermal and mechanical loads. A finite element model in conjunction with a cohesive zone model (CZM) is used in order to determine the location of joint separation as well as the contribution of each mode in damage (debonding) initiation. The composite beam is modeled by using two layers of aluminum that are bonded together through a layer of adhesive. Simulation results show that the model can successfully detect the location of damage under a thermo-mechanical load. The model can also be used to determine the severity of damage due to a thermal load, a mechanical load and a thermo-mechanical load. It is observed that integrating thermal analysis has a significant influence on the fracture energy.
Experimental Study on Complex Modes of an End Damped Continuous Beam
Authors: Xing Xing , Feeny Brian F.
Published: July 2018

The complex modes of an end-damped cantilevered beam are studied as an experimental example of a non-modally damped continuous system. An eddy-current damper was applied considering its noncontact and linear properties. The state-variable modal decomposition (SVMD) is applied to extract the modes from the impact responses in the cantilevered beam experiments. Characteristics of the mode shapes and modal damping are examined for various values of the damping coefficient. The modal frequencies and mode shapes obtained from the experiments have a good consistency with the results of the finite-element model. The variation of damping ratio and modal nonsynchronicity with varying damping coefficient also follow the prediction of the model. Over the range of damping coefficients studied in the experiments, we observe a maximum damping ratio in the lowest underdamped mode, which correlates with the maximum modal nonsynchronicity. Complex orthogonal decomposition (COD) is applied in comparison to the modal idenfication results obtained from SVMD.
Free Vibration of Flexible Cables
Authors: Arena Andrea
Published: July 2018

The free undamped vibrations of cables undergoing stretching, bending and twisting are investigated. To this end, a geometrically exact model of elastic cables accounting for bending and torsional stiffness is employed. The cable kinematics retain the full geometric nonlinearities. Starting from a prestressed catenary configuration, the nonlinear equations of motion are linearized about the initial equilibrium. In particular, two initial equilibrium states (shallow and taut) are considered while varying the cable elastic axial stiffness. The influence of the bending flexibility on the cable frequencies is assessed by direct comparisons with the frequencies predicted by classical cable theories of purely extensible cables.
Damping Characteristics of Non-Synchronous Turbine Blade Vibration
Authors: Akiyama Ryou , Shiohata Koki , Nakajima Tomomi , Yamashita Yutaka
Published: July 2018

In order to analyze turbine blades vibration caused by flutter, it is necessary to understand both aerodynamic damping and structural damping of high vibration stress. Flutter Vibration mode occurring in rated speed is non-synchronous mode. For measuring non-synchronous mode damping ratio of turbine blades, AC-type electromagnet which can generate high frequency excitation force was developed. Damping ratio characteristics of non-synchronous mode of nodal diameter 12,4 was measured in rotational test. For comparison, synchronous mode of nodal diameter 4 was measured, too. It was concluded as follows. (1) It is possible to excite non-synchronous mode by high frequency excitation electromagnet and calculate damping ratio from measurement resonance curve. (2) Damping ratio of non-synchronous mode ND12,4 was increased by increasing the excitation force. Synchronous mode ND4 is also a similar trend. (3) Nodal diameter 4 damping ratio of non-synchronous mode (Resonant speed=100%) was lower than synchronous mode (Resonant speed=75%).
Numerical Simulation of Partial Slip Contact Using a Semi-Analytical Method
Authors: Armand J. , Salles L. , Schwingshackl C. W.
Published: July 2018

Almost all mechanical structures consist of an assembly of components that are linked together with joints. If such a structure experiences vibration during operation, micro-sliding can occur in the joint, resulting in fretting wear. Fretting wear affects the mechanical properties of the joints over their lifetime and as a result impacts the non-linear dynamic response of the system. For accurate prediction of the non-linear dynamic response over the lifetime of the structure, fretting wear should be considered in the analysis.

Fretting wear studies require an accurate assessment of the stresses and strains in the contacting surfaces of the joints. To provide this information, a contact solver based on the semi-analytical method has been implemented in this study. By solving the normal and tangential contact problems between two elastic semi-infinite bodies, the contact solver allows an accurate calculation of the pressure and shear distributions as well as the relative slips in the contact area. The computed results for a smooth spherical contact between similar elastic materials are presented and validated against analytical solutions. The results are also compared with those obtained from finite element simulations to demonstrate the accuracy and computational benefits of the semi-analytical method. Its capabilities are further illustrated in a new test case of a cylinder with rounded edges on a flat surface, which is a more realistic contact representation of an industrial joint.
Dynamic Behaviour of Ox Tibial and Femoral Bones: A Comparison With Human Bones
Authors: Hoursan Hesam , Ahmadian Mohammad Taghi
Published: July 2018

Finite element models have been widely employed in an effort to quantify the stress and strain distribution around human bones as well as implanted prostheses and to explore the influence of these distributions on their long-term stability. In order to provide meaningful predictions, such models must contain an appropriate reflection of mechanical properties. Detailed geometrical and density information is now readily available from CT scanning. However, there are still many complications regarding patient-specific geometrical differences and bone dynamic behavior in-vivo. Experimental studies on animal bones, due to their convenience and accessibility, have always played a key role in simulating human bone behavior. In current study, a modal experiment has been done on an ox femoral and tibial bones and the results have been compared with those reported from human bones. Results have been obtained in terms of natural frequencies of medio-lateral bending mode shapes and damping ratios, and compared with those obtained by some previous studies. The results suggest similar pattern in modal behavior, but considerable difference between natural frequencies due to geometrical differences. To consider structural damping ratios, due to existence of moisture and marrow in bone in-vivo, samples have been obtained few hours post-mortem and the ratio has been extracted for each natural frequency.

Finally, conclusions have been made on the similarity of the models and how to improve the FE models of human tibial and femoral components.
Rotating Machinery Long Coupling Spacer Related Vibration
Authors: Kirk Gordon
Published: July 2018

The increased speed and power level of rotating machinery most often bring the problem of non-synchronous instability. Many of the current most interesting problems, have been caused by synchronous thermal instability. These problems are related to the machinery overhangs predominantly, many are due to heavy couplings and the associated fluid film bearing non-uniform heating of the rotor shaft coupling end journal area. For couplings with long spacer tubes, other causes of excessive synchronous vibration are worthy of discussion. Long coupling spacer tubes with balance correction made at low speed and operating in service too near the coupling spacer critical speed can result in excessive synchronous vibration. Once the spacer has large mid-span amplitude, additional nonlinear vibration can occur. This paper discusses a recent occurrence of this interesting problem and will show why it should not be overlooked in future coupled multi-body high speed machinery trains, or any driveshaft balanced only at the shaft end plains.
Neural-Network Vibration Control of Rings With Light-Activated Shape Memory Polymer Actuators
Authors: Li Huiyu , Li Hua , Tzou Hornsen
Published: July 2018

The light-activated shape memory polymer (LaSMP) is sensitive to ultraviolet light with specific wavelength. It is featured with dynamic stiffness. In this study, LaSMP is used to control the vibration of thin ring shells induced by external loading. Firstly the variation of LaSMP’s Young’s modulus is modeled. The mathematical model reflects the influence of light intensity, the decay coefficient and thickness of LaSMP. Besides, the model is suitable for LaSMPs with different reaction orders. Then, with Lamé parameters and the radii of rings the governing equations of the flexible ring laminated with LaSMP actuators are established. Love operators of LaSMP actuators are derived. Based on the mode expansion method, the modal forces of external loading and LaSMP actuators are given. The modal participation factors are analyzed with the modal forces. As the variation of Young’s modulus to the light intensity is nonlinear, the control effect of LaSMP actuators to common harmonic excitation is not perfect. Because the neural network control is effective to identify complex models, it is introduced to adjust the profile of light intensity. In the case study, the model of LaSMP’s Young’s modulus is validated with the experimental data. Then the forced harmonic responses of the ring are studied. For the mode n=2, the modal participation factor is reduced by 47.7% with the control of LaSMP actuator. To further enhance the control effect, the phase shift method is applied. With π/6 phase shift, the modal participation factor is reduced by 80.8%. With the neural network control method, the modal participation factor is cut down by 98.1%. The study shows that LaSMP actuator provides a new choice to control the forced vibration of flexible rings. It is also possible to apply LaSMP actuator to vibration control of other thin shell structures.
Real Time Dynamic System Stochastic Identification in Video Capture for Data Compression, Image Interpolation, Prediction, and Augmented Reality
Authors: Goeller Adrien , Dion Jean-Luc , Soriano Thierry , Roux Bernard
Published: July 2018

In computer vision, cameras more and more accurate, fast, 3D featured are used. These still evolutions generate more data, which is an issue for users to store it with standard compression for example for recording proof in case of products manufacture defective.

The aim of this work is to develop a specific solution adapted for vision systems which have a known scenario and can be described by dynamic models. In this framework, Kalman filters are used for data compression, observable variable prediction, and augmented reality. The developed concepts are tested with a scenario of a ruler on a table. The experiment aims to check the data compression level, the estimation of the friction forces coefficient of the ruler and the prediction of the stop position.
Full-Field Strain Monitoring of a Wind Turbine Using Very Limited Set of Displacements Measured With Three-Dimensional Point Tracking
Authors: Baqersad Javad , Poozesh Peyman , Niezrecki Christopher , Avitabile Peter
Published: July 2018

In the current work, the optical three-dimensional point-tracking (3DPT) measurement approach is used in conjunction with a recently developed modal expansion technique. These two approaches (empirical and analytical) complement each other and enable the prediction of the full-field dynamic response on the surface of the structure as well as within the interior points. The practical merit of the approach was verified using a non-spinning and spinning wind turbine rotor. The three-bladed wind turbine rotator was subjected to different loading scenarios and the displacement of optical targets located on the blades was measured using 3DPT. The measured displacement was expanded and applied to the finite element model of the turbine to extract full-field strain on the turbine. The sensitivity of the proposed approach to the number of optical targets was studied in this paper. It is shown the approach can accurately predict the strain even with very few set of measurement points.
Optimal Attachment of a Secondary, Bender-Type Resonator to a Flexible Base Beam for Energy Harvesting Applications
Authors: Lundstrom Troy , Jalili Nader
Published: July 2018

The application of piezoelectric bender actuators as active resonators for energy harvesting may prove to be advantageous over uniaxial actuators as they can extract both rotary and translational energy from a flexible base. In addition, this minimizes the likelihood that the attachment location is the node of a mode (rotary or translational). In this paper, the equations of motion/boundary conditions are presented for a continuous two-beam system composed of a cantilevered, primary base beam with a secondary bender mounted to its surface. The secondary bender is composed of piezoelectric material. To generalize the analyses performed in this work, the equations were nondimensionalized. Using the nondimensionalized equations of motion, a tuning procedure is described to match the first natural frequency of the actuator beam to an arbitrary natural frequency of the base beam. The actuator beam was tuned to the first natural frequency of the base beam and a sensitivity study was performed to show the effect of the actuator beam attachment location on the system natural frequencies and mode shapes. Using the mode shape waterfall plots, a brief study was also performed to determine the percent strain energy in the actuator beam relative to the total system strain energy for the first four system modes.
Prediction and Measurement of Payload Swing From Off-Centered Crane Lifts
Authors: Peng Kelvin , Singhose William
Published: July 2018

When crane payloads are lifted off the ground, the payload may unexpectedly swing sideways. This occurs when the hoist cables are at an angle relative to vertical and the payload is not directly beneath the hoist. Because the hoist point is far above the payload, it is difficult for crane operators to know if the hoist cable is perfectly vertical before they start to lift the payload. Some amount of horizontal motion of the payload will always occur at lift off. If an off-centered lift results in significant horizontal motion, then it creates a hazard for the human operators, the payload, and the surrounding environment. This paper develops dynamic models of off-centered lifts and presents experimental verification of the theoretical predictions. To mitigate the detrimental effects of off-centered lifts, autonomous-centering solutions are proposed.
Simultaneous Output-Only Identification of Physical Parameters and Unknown Inputs for Linear Mechanical Systems
Authors: Ghobadi Mostafa , Majji Manoranjan , Esfahani Ehsan T.
Published: July 2018

This paper has studied the identification problem of linear mechanical systems where inputs are unknown and only displacement data are accessible for measurement. Eigensystem Realization Algorithm (ERA) has been used along with physical constraints considerations in time domain to simultaneously identify two separate models for the physical system and the unknown inputs. Inputs are assumed to be an arbitrary combination of harmonic signals with frequencies higher than natural frequencies of the physical system by which a linear mechanical system is meant in this paper. Adding physical constraints and utilizing canonical real Jordan form of the identified system leads to a unique analytical solution. To validate the theory part, a set of simulations has been run that demonstrates the physical parameters and input model can be estimated accurately.
Heartbeat Energy Harvesting Using the Fan-Folded Piezoelectric Beam Geometry
Authors: Ansari M. H. , Karami M. Amin
Published: July 2018

A three dimensional piezoelectric vibration energy harvester is designed to generate electricity from heartbeat vibrations. The device consists of several bimorph piezoelectric beams stacked on top of each other. These horizontal bimorph beams are connected to each other by rigid vertical beams making a fan-folded geometry. One end of the design is clamped and the other end is free.

One major problem in micro-scale piezoelectric energy harvesters is their high natural frequency. The same challenge is faced in development of a compact vibration energy harvester for the low frequency heartbeat vibrations. One way to decrease the natural frequency is to increase the length of the bimorph beam. This approach is not usually practical due to size limitations. By utilizing the fan-folded geometry, the natural frequency is decreased while the size constraints are observed. The required size limit of the energy harvester is 1 cm by 1 cm by 1 cm.

In this paper, the natural frequencies and mode shapes of fan-folded energy harvesters are analytically derived. The electro-mechanical coupling has been included in the model for the piezoelectric beam. The design criteria for the device are discussed.
Design Procedure of an Eddy Current Damper Type Reaction Force Compensation (RFC) Mechanism for a Linear Motor Motion Stage
Authors: Ahn HyeongJoon
Published: July 2018

Base vibration of a linear motor motion stage has been reduced with passive RFC mechanism based on movable magnet track and springs. This paper presents design procedure of an eddy-current damper (ECD) type RFC mechanism for a linear motor motion stage. The RFC mechanism with a movable magnet track and an ECD can overcome disadvantages of the spring based RFC mechanism such as resonance and difficulty of assembly due to spring. A lumped parameter model for the ECD type RFC mechanism is derived considering sinusoidal magnetic flux density and effective width of the ECD according to magnet track motion. Then, a design procedure for ECD type RFC mechanism is proposed to meet system requirements such as transmission ratio of reaction force and maximum magnet track motion. Design example illustrates the effectiveness of the proposed design procedure for ECD type RFC mechanism.
Development of Recurrence Analysis for Fault Discrimination in Gears
Authors: Kwuimy C. A. Kitio , Kankar P. K. , Chen Y. , Chaudhry Z. , Nataraj C.
Published: July 2018

Most of the current approaches in gear fault diagnostic analysis do not provide a clear indication for discrimination between various common faults. This is almost certainly because failure in gear systems is always accompanied with a complex dynamic response. The inherent nonlinearities in geared systems and additional nonlinearity due to faults conspire to make the diagnostics problem extremely complex. The main goal of this paper is to exploit the nonlinear response in an attempt to solve this challenging problem. We aim to demonstrate effective discrimination between four kinds of common defects in gears by utilizing the method of recurrence analysis. We consider a healthy system, a system with a single crack, a system with multiple cracks and a system with a missing tooth. Careful measurements are collected from an experimental set up which is a mock-up of a real industrial gear box system. We develop and apply recurrence plot analysis to this data. Our results show that recurrence analysis parameters such as recurrence rate, trapping time, entropy and maximal diagonal length can be very effective in successful discrimination of gear faults.
Observed Rotordynamic Phenomena in Aircraft Gas Turbine Development
Authors: Ehrich Fredric F.
Published: July 2018

Observations, analysis and understanding of out-of-the-ordinary rotordynamic phenomena (including several instabilities and nonlinear responses) observed in aircraft gas turbine engines and other high-speed rotating machinery over the course of the author’s career in the design and development of aircraft gas turbine engines are described. Some observed phenomena were already widely recognized in the rotordynamic community such as:

• Hysteretic whirl

• The tip clearance effect on stability of turbomachinery rotors

• Instability due to trapped liquids in the rotor

• Hysteresis in the resonant peak amplitude

• Effective suppression of rotor instability by anisotropy in the engine support structure

Other observations were fairly new to the field of rotordynamics at that time they were observed but were identified as being new manifestations of vibration phenomena already familiar to vibration technologists in fields other than high-speed rotordynamics such as:

• Sum-and-difference frequency response

• Relaxation oscillations

• Nonlinear effects of anisotropic clearance in roller and gas bearings

At that time these phenomena were observed, the pressure for remediation of the problems they represented in the context of ongoing aircraft engine development resulted in intense attention and analysis which, in turn, often resulted in new insights, useful diagnoses, and effective remedial actions.
Solid-Lattice Hip Prosthesis Design: Applying Topology and Lattice Optimization to Reduce Stress Shielding From Hip Implants
Authors: He Yuhao , Burkhalter Drew , Durocher David , Gilbert James M.
Published: July 2018

The goal of this study was to construct a design methodology for a prosthesis which causes less stress shielding and meets fatigue requirements. Stress shielding is the reduction in bone stresses due to the introduction of an implant. Implants may become loose when stress shielding is present because bone resorption occurs as the bone adapts to the reduced bone stresses. Topology and lattice optimization were performed using OptiStruct to design a hip prosthesis where stress shielding and prosthesis fatigue were considered. The optimized design reduced stress shielding by 50+% when compared to a conventional generic implant, and the fatigue life met the ISO standards. Additionally, manufacturability was considered in the design process and a Ti-6Al-4V prototype was printed with an EOS selective laser melting machine.
Design and Development of a Soft Robotic Back Orthosis
Authors: Govin Deven , Saenz Luis , Athanasaki Grigoria , Snyder Laura , Polygerinos Panagiotis
Published: July 2018

Chronic back pain is a disorder which affects a large portion of the American population at some time during their lifespan. There are many causes for lower back pain and usually can be an indicator of a serious medical condition. This problem plagues the nation and the world leading to an estimated annual cost for back pain treatment amounts to $50 billion. This problem isn’t isolated to just the United States either, the world at large suffers from back pain and unfortunately modern treatment methods are effective but the technology simply hasn’t progressed in decades. The main drawback appears to be the rigidity of the device, which limits flexibility and comfort. The soft pneumatic actuators of this newfound device have the potential to provide the appropriate applications chronic back pain suffers and post-surgery patients.

In this work, the design and development of a soft robotic back orthotic device that has the capability to relieve back pain by assisting patients to fully achieve the upright position and stabilize the lumbosacral spine, is presented. The soft robotic actuators of this device allow the support to be disabled when the patient is in a supported position. Unlike conventional robotic assistive devices, this pneumatically actuated back orthosis provides dynamic support while being lightweight, comfortable, and cost affordable. After testing the device in a laboratory environment, the data overall displays a trend decreasing in EMG activity of the Erector Spinae muscles. This reduced activity leads to a reduction in strain on the patient.
Optimization of Surface Scaffold Morphology and Structure Using Taguchi’s Design of Experiments
Authors: Bhargav Aishwarya , Rosa Vinicius , Wen Feng Lu , Fuh Jerry Y. H.
Published: July 2018

Additive Manufacturing or 3D Printing as it is commonly known is increasingly being used in the manufacturing of tissue engineering scaffold. The process allows for just in time production and customization. Hence, optimizing and varying the morphology of the tissue engineering scaffold in accordance to the application is one of the advantages of 3D printing. This paper aims to optimize the surface scaffold morphology by varying the dimensional parameters such as pore size, fibre diameter, orientation of fibres on scaffold and number of layers on the scaffold. The paper makes use of Taguchi’s Design of Experiments to understand and analyse the relationship between the different parameters that influence the morphological and mechanical characteristics of the scaffold.
Isometric Quadriceps Strength Test Device to Improve the Reliability of Handheld Dynamometry in Patient With Anterior Cruciate Ligament Injury
Authors: McNamara Stephanie , Gallardo Hevia Elizabeth , St. Louis Reggie , Cho William , Lee Sangjun , Moyne Martina , Quinlivan Brendan , Payne Christopher J. , Walsh Conor , Schiller Greg , Awad Louis N.
Published: July 2018

Anterior cruciate ligaments (ACL) injuries account for a significant proportion of all sports-related injuries. Despite successful completion of a rehabilitation program, about 35% of ACL patients experience re-injury after return to sport, and studies have identified persistent quadriceps strength deficits as a potential cause [1–3]. Deficits in quadriceps strength can be monitored throughout rehabilitation using muscle strength testing. The most common test protocol involves isometric testing of quadriceps strength whereby the knee is extended against a static resistance. In this method, the clinician uses their strength to resist the patient’s motion and subsequently assigns a qualitative value of strength. The highly subjective nature of this test has motivated clinicians to use devices that can more accurately assess quadriceps strength.
A Framework of Simulating Virtual Spine Patients to Assess Thoracic Volume Variations due to Wedging Deformities
Authors: Lee Po-Chih , Erdman Arthur G. , Ledonio Charles , Polly David
Published: July 2018

In 1964, Dr. Barrows first introduced the standardized patients, who are individuals trained to imitate the pathological symptoms of the real patients, and involved them in teaching and clinical skills assessment for healthcare education. In recent decades, the application of the virtual patient has been rapidly grown and has been widely used in clinical or educational practice among residents, surgeons, or other medical professionals because the virtual patient is cost-effective and time-efficient [1]. The Food and Drug Administration (FDA) collaborated with the Foundation of Research on Information Technologies in Society (IT’IS Foundation, Zürich, Switzerland) to produce a virtual family, which is a set of anatomical computer-aided design (CAD) models of adults and children [2, 3], and those CAD models are used in electromagnetic, thermal, and computer fluid dynamics simulations. However, the meaning of virtual patients or models has varied across the recent years and more and more researchers tried to categorize the terminology of virtual patients. In general, virtual patients can be classified into seven major types including: case presentation, interactive patient scenarios, virtual patient game, high fidelity software simulation, human standardized patients, high fidelity manikins, and virtual standardized patients [4]. The virtual patients discussed in this study can be classified as interactive patient scenarios, whose application includes clinical reasoning, surgical planning, and disease diagnosis.
Automation of Suturing Path Generation for da Vinci-Like Surgical Robotic Systems
Authors: Dehghani Hossein , Farritor Shane , Oleynikov Dmitry , Terry Benjamin
Published: July 2018

Minimally invasive surgery (MIS) has substantially improved surgery by reducing patient pain, discomfort, and tissue trauma [1]. MIS, however, has shortcomings including limited workspace, reduced surgeon’s dexterity, and poor eye-hand coordination [2]. Robot-assisted minimally invasive surgery (RMIS) has aimed to mitigate these limitations [3]. The da Vinci® Surgical System (Intuitive Surgical, Inc., Sunnyvale, CA) is the-state-of-the-art RMIS, in which the surgeon operates by using the console’s master controllers to maneuver the patient-side robotic arms, where the surgeon’s hand movements are refined through motion scaling and tremor reduction. Over half a million procedures are performed using the da Vinci annually [4].
Computational Fluid Dynamics Modeling of Blood As a Heterogeneous Fluid
Authors: Smithee Isaac , Gent Stephen P.
Published: July 2018

As the medical field continues to increase its effectiveness and scope, computational fluid dynamics (CFD) has become essential to understanding flow mechanics cardiovascular systems. Many simulations and experiments have been conducted to confirm the behavior of blood within veins and arteries, under both Newtonian and non-Newtonian conditions. Traditionally, these simulations have been conducted where blood is represented as a homogeneous fluid. However, blood is a heterogeneous fluid mixture, consisting of fluid plasma and solid components of red blood cells (RBC), white blood cells (WBC), and platelets. The effects of the heterogeneity of blood becomes more influential in blood flows through smaller diameter vessels and high velocity flows, as the addition of particles will create variations in flow speed, shear stress, and fluid displacement due to particle-particle and particle-wall collisions [1].
The Application of Deep Learning for the Classification of Internal Human Cardiac Anatomy
Authors: Gaasedelen Erik , Deakyne Alex , Iaizzo Paul
Published: July 2018

The applications of sensing and localization are becoming more sophisticated in many invasive and non-invasive surgical procedures and there is great interest to apply them to the human heart. Ideally, such tools could be indispensable for allowing physicians to spatially understand relative tissue morphologies and their associated electrical conduction. Yet today there remains a steep divide between the creation of spatial environment models and the contextual understandings of adjacent features. To begin to address this, we explore the problem of anatomical perception by applying deep learning to the identification of internal cardiac anatomy images.
Identifying Properties for an Aortic Stent-Graft That Counteracts Hypertension
Authors: Kizilski Shannen B. , Amili Omid , Coletti Filippo , Faizer Rumi , Barocas Victor H.
Published: July 2018

In 2017, the American Heart Association reported that one third of deaths in the United States, and 31% of deaths worldwide, are attributed to cardiovascular disease (CVD) [1]. A risk factor pervasive across most types of CVD is chronic high blood pressure, or hypertension [2].
Preliminary Investigation of the Mechanics of a Novel Thoracic Cavity Extra Pulmonary Oxygenation Device
Authors: Aghabaglou Fariba , Buesing Keely , Legband Nathan D. , Slagle Connor , Xie Wanchuan , Borden Mark , Kreikemeier-Bower Craig , Terry Benjamin S.
Published: July 2018

Acute respiratory distress syndrome (ARDS) arising from trauma, sepsis, pneumonia or other diseases has been acknowledged to be a major clinical problem in respiratory medicine. Hypoxia and hypercapnia arising from ARDS are life-threating particularly in children and elderly people. The reported mortality rate for ARDS is high. Current methods for treating patients who have limited or no lung function are ineffective or insufficient and present additional risks to the patients. In this research, we have explored new methods of infusing phospholipid-coated oxygen microbubbles (OMBs) to the thoracic cavity in order to oxygenate patients suffering from ARDS and hypoxemia. In our previous work, OMBs have been shown to be effective in treating hypoxia in models of LPS lung injury and lung trauma in rats and rabbits. In this study, we have developed a novel thoracic cavity extrapulmonary oxygenation devices using OMBs and test this device in a benchtop test and in vivo experiment on a large animal (pig) right pneumothorax injury model.
Heatguard: An Ultra-Low-Cost 3D Printed Sensor for Body Temperature Alert and Reporting System
Authors: Li Rui , Smith Aaron A. , Tadinada Harshitha S. , Tse Zion T. H.
Published: July 2018

The thermochromic device is a low-cost 3D-printed bracelet. It has the function of reading body temperature and warns individuals of the potential risk for heat related illnesses. The product is created from a thermochromic resin that is sensitive to temperature. This product can be customized to fit different age groups such as children and elders. Combined with the smartphone application, the device can provide realtime body temperature monitoring and alert to people who are vulnerable to heatstroke.
Computational Simulations of Ventricular Outflow Tract Obstructions Associated With Varied Replacement Valve Geometries
Authors: Zhingre Sanchez Jorge D. , Mattison Lars M. , Bateman Michael G. , Iaizzo Paul A.
Published: July 2018

Transcatheter replacement therapies for the atrioventricular (AV) valves are considered as the next frontier for the treatment of valvular regurgitation. The AV valves, tricuspid and mitral, are the regulators of blood flow from the atria into the ventricles. During diastole, blood flows through the open tricuspid and mitral valves to fill the right and left ventricles, respectively. During systole, the ventricles contract, closing the AV valves, and forcing the blood to exit through their respective ventricular outflow tracts (VOTs) to the arterial circulations. Although the current gold standard for the treatment of valvular regurgitation is surgical replacement or repair, the field of transcatheter therapies is rapidly expanding as new treatment options for patients; especially for those individuals considered to be at greater risks for surgical complications. Market released bioprosthetic devices for replacing the aortic and pulmonary valves have shown great promise and success. However, the advancement of similar therapies for either the mitral and tricuspid valves remain in the early stages of development. This slower progress is attributed to the high complexities and variabilities of the AV valves, which present challenges for both device design and post-implantation functions.
In Vitro Functional Verification of a Novel Laxity Measurement Stress Radiography Device
Authors: Beukes Giancarlo L. , Patnaik Sarthak , Sivarasu Sudesh
Published: July 2018

The human knee is a hinge joint, primarily facilitating locomotion. Knee joint instability, due to ligament injuries (anterior cruciate ligament [ACL], posterior cruciate ligament [PCL], medial collateral ligament [MCL] and lateral collateral ligament [LCL]), is a result of direct or indirect trauma, non-anatomical stresses during pivoting movements about the knee, imbalanced landing during jumping and rapid deceleration during high intensity locomotion [1]. Biomechanical indications of an unstable knee joint include decreased joint integrity, hyper laxity, abrupt locking and catching combined with clicking noises during locomotion. Approximately, two hundred and fifty thousand ACL injuries occur in the United States of America, annually [2].
Design of a Thumb Strength Testing Device
Authors: Fry Christian , Mardula James , Lee Brandon , Piovesan Davide
Published: July 2018

The scope of the project was to design a pneumatic cylinder for measuring the resistive and applied force of the flexor pollicis longus (FPL) after anterior interosseous nerve (AIN) surgery. The patient’s distal section of the first phalange, of the thumb, is the area of evaluation. The device is intended for assessing both the quality of the surgery results as well as physical therapy progression. Criteria such as mobility, compact design, accuracy, repeatability, and ease of operation are some of the major requirements. The initial prototype is intended to collect FPL strength data to establish operating conditions.
Design of a Novel Task-Based Knee Rehabilitation Exoskeleton Device
Authors: Adhikari Visharath , Yihun Yimesker , Lankarani Hamid M.
Published: July 2018

This study is aimed at the design of a novel task-based knee rehabilitation device. The desired trajectories of the knee have been obtained through a vision-based motion capture system. The collected experimental kinematic data has been used as an input to a spatial mechanism synthesis procedure. Parallel mechanisms with single degree-of-freedom (DOF) have been considered to generate the complex 3D motions of the lower leg. An exact workspace synthesis approach is utilized, in which the parameterized forward kinematics equations of each serial chains of the parallel mechanisms are to be converted into implicit equations via elimination. The implicit description of the workspace is made to be a function of the structural parameters of the serial chain, making it easy to relate those parameters to the desired trajectory. The selected mechanism has been verified for the accuracy of its trajectory through CAD modeling and simulations. This design approach reduces alignment and fitting challenges in an exoskeleton as the mechanism does not require alignment of each robotic joint axis with its human counterpart.
Biomechanical Responses of Swine Esophagus Tissue to Irreversible Electroporation
Authors: Mattison Lars M. , Johnson Chloe , Iaizzo Paul A.
Published: July 2018

Atrial Fibrillation (AF) is a common disease that may occur in the heart, especially as we age. AF is due to non-normal myocardial ectopic foci that then causes an uncoordinated atrium contraction. This effectively reduces the atrial kick to the ventricles, which can account for up to 20% of ventricular filling. While not an immediately fatal disease, it can cause reduced quality of life for patients and also puts them at increased risk for stroke. AF as a disease, is expected to affect over 50 million people in the United States alone by 2050 [1].
Development of Pyro Igniter for Gas Turbine Engine Application
Authors: Jayaraman K.
Published: July 2018

As the initiation of ignition of gas turbine combustor is relying on conventional spark plug methods, it has some limitations at fuel lean mixture conditions, turbulence streams and high altitude relight conditions. Severely reduced spark plug performance and durability is an unfortunate consequence as engines are simultaneously being pushed to higher power densities and leaner stoichiometry in order to improve efficiency and lower emissions. However, an important parameter is the ignition under extreme conditions, lean combustible mixture and high initial pressure, requiring high voltage when using conventional spark plug technology and also significantly reduces the lifetime. An alternative solution to standard spark plug is the use of pyro materials to igniter applications. The overall energy conversion efficiency from chemical energy to electrical energy and mechanical energy will be less when compared to direct conversion of chemical energy to the required applications. Also, the pyro type sources are compact in size. In the gas turbine the exploitation of pyro igniter is inevitable. This research paper involves the demonstration of chlorine free propellant formulation, burning rate studies, application and compatibility of pyro igniter to initiate the ignition of gas turbine combustor. Ammonium Nitrate (AN) plus polymer binder (Hydroxyl Terminated Poly Butadiene – HTPB) and Ammonium Dichromate (ADC) catalyst based composite propellant pyro igniter material have been considered. This composite propellant delivers comparatively low performance, low temperature and low burn rate when compared to Ammonium Perchlorate (AP) based propellant. But AP based propellants discharges corrosive (HCl) gases. AN based composite propellant have chosen for the clean exhaust and non-toxic gases. The impact sensitivity of AN based propellant is quite normal comparable with AP based compositions and low when compared to double based propellants. The burning rate of the propellant is measured in 10 to 60 bar pressure range. The pyro igniter is fabricated and ignition tests are conducted. Average energy release rate of the pyro igniter is 16.6 KJ/s in the designed configuration.
Influence of Different Rib Height on Heat Transfer Augmentation in Rectangular Convergent / Divergent Channels With Continuous Ribs on Bottom Surface
Authors: Sivakumar K. , Natarajan E. , Kulasekharan N.
Published: July 2018

The work reported in this paper is a systematic experimental study of friction and heat transfer characteristics of divergent /convergent rectangular ducts with an inclination angle of 1° in the y-direction. Measurements were taken for a convergent / divergent rectangular channel of aspect ratio, AR = 1.25 to 1.35 with three uniform rib heights, e = 3, 6 and 9 mm the ratio between rib height (e) to hydraulic mean diameter (Dm) are 0.0348, 0.0697 and 0.1046, a constant rib pitch distance, P = 60 mm. The flow rate in terms of average Reynolds numbers based on the hydraulic mean diameter (Dm) of the channel was in a range of 20000 to 50,000 is 0.085 m. A ceramic strip of 10 mm thickness is used as a heating coil has been attached on top and bottom surfaces for the test sections. The heat transfer characteristics degraded with increase in the rib height in 90° attached ribs over smooth channel. The heat transfer performance of the divergent/convergent ducts for 3, 6 and 9 mm ribs was conducted under identical mass flow rate based on the Reynolds number. In convergent duct having three test sections each having three different size ribs 3, 6, and 9mm. Similarly, divergent section is also three different rib heights duct. So, in our experiments has totally 6 different ducts were used. In addition, the acceleration / deceleration caused by the cross section area, the divergent duct generally shows enhanced heat transfer behavior for three different rib sizes, while the convergent duct has an appreciable reduction in heat transfer performance.