bluuebunny/crossref_metadata_2025 huggingface dataset:
Ophthalmic contributions to assessing eyes of two neotropical canids: Cerdocyon thous and Chrysocyon brachyurus
Authors: Carvalho Clarissa M. , Rodarte‐Almeida Ana C. V. , Beanes Alan S. , Machado Marilia T. S. , Galera Paula D.
Published: January 2020

Objective

To describe selected ophthalmic tests and anatomical features of eyes of crab‐eating foxes (Cerdocyon thous) and maned wolves (Chrysocyon brachyurus).

Animals studied

Six crab‐eating foxes (12 eyes), eight maned wolves (16 eyes).

Procedures

Intramuscular and/or inhalatory anesthesia, ophthalmic evaluation with portable slit‐lamp biomicroscope, Schirmer tear test (STT), intraocular pressure measurement with rebound and applanation (crab‐eating fox only) tonometers, measurement of palpebral fissure length (PFL), gonioscopy, and fundoscopy. Data were analyzed with ANOVA and Tukey's tests.

Results

Both species presented upper and lower eyelids, both with eyelashes and Meibomian glands openings. A third eyelid was also present. In partial miosis, pigmented projections were observed along the edge of the pupil. The draining angle was open, with thin pectinate ligaments. The retina was holangiotic. For crab‐eating foxes, mean ± standard deviation values were as follows: STT: 4.33 ± 2.96 mm/min; PFL: 17.45 ± 1.55 mm; rebound tonometry: 10.70 ± 3.43 mm Hg (TonoVet® calibration D),5.66 ± 3.44 mm Hg (TonoVet®calibration P), 17.00 ± 4.64 mm Hg (TonoVet® Plus calibration dog); and applanation tonometry: 11.70 ± 5.70 mm Hg(TonoPen® XL). For maned wolves, the mean ± standard deviation values were as follows: STT: 9.31 ± 7.40 mm/min; PFL: 22.79 ± 1.63 mm; rebound tonometry: 11.00 ± 2.77 mm Hg (TonoVet® calibration D), 6.78 ± 2.58 mm Hg (TonoVet® calibration P), and 18.29 ± 3.47 mm Hg(TonoVet® Plus calibration dog).

Conclusions

This study contributes with knowledge that can help the clinical assessment regarding eyes of crab‐eating foxes and maned wolves. The data herein presented for rebound tonometry are new for both species.
Cryptic diversity in ant‐mimic Micaria spiders (Araneae, Gnaphosidae) and a tribute to early naturalists
Authors: Muster Christoph , Michalik Peter
Published: January 2020

Spiders of the genus Micaria are ground‐living mimics of ants. Species delineation in these spiders is challenging, mainly because of exceptional high levels of intraspecific variation masking species boundaries. As implied by preliminary DNA barcode data from Central Europe, the Holarctic and very widely distributed glossy ant‐spider M. pulicaria shows cryptic diversity. Here, we disentangle the hidden diversity by means of an integrative taxonomy approach, using mitochondrial DNA, morphometrics, traditional genitalic characters and ecology. Our data suggest the clear delineation of two distinct species, which supports the conception of 19th century taxonomists. These early naturalists distinguished M. pulicaria and a second closely related species based on morphology and natural history, which were synonymized in subsequent taxonomic studies. Therefore, we re‐circumscribe M. pulicaria and revalidate the long forgotten M. micans. These two Micaria species co‐occur sympatrically in vast areas of the western Palearctic, while the Nearctic region is populated by M. pulicaria alone. Male genitalic traits are more dissimilar in the area of sympatry than in allopatry, suggesting a decisive role of reproductive character displacement in species diversification. Our study emphasizes the value of the early taxonomic literature in integrative taxonomic studies, as it may contain crucial information on natural history that are not regularly recorded by modern taxonomists.
Fuzzy-FMSA: Evaluating Fault Monitoring and Detection Strategies Based on Failure Mode and Symptom Analysis and Fuzzy Logic
Authors: Murad Carlos Alberto , Melani Arthur Henrique de Andrade , Michalski Miguel Angelo de Carvalho , Caminada Netto Adherbal , de Souza Gilberto Francisco Martha , Nabeta Silvio Ikuyo
Published: January 2020

Failure mode and symptoms analysis (FMSA) is a relatively new and still not very much employed variation of failure modes, effects and criticality analysis (FMECA), a technique broadly used in reliability, safety, and quality engineering. While FMECA is an extension of the well-known failure mode and effects analysis (FMEA) method, primarily used when a criticality analysis is required, FMSA focuses on the symptoms produced by each considered failure mode and the selection of the most appropriate detection and monitoring techniques and strategies, maximizing the confidence level in the diagnosis and prognosis. However, in the same way as FMECA and FMEA, FMSA inherits some deficiencies, presenting somewhat biased results and uncertainties intrinsic to its development, due to its own algorithm and the dependence on knowledge-based inputs from experts. Accordingly, this article presents a fuzzy logic application as a complement to FMSA in order to mitigate such uncertainties' effects. As a practical example, the method is applied to a Kaplan turbine shaft system. The monitoring priority number (MPN) obtained through FMSA is compared to the fuzzy monitoring priority number (FMPN) resulting from fuzzy logic application, demonstrating how the proposed method improves the evaluation of detection and monitoring techniques and strategies.
Diagnostics as the Key to Advances in Global Health: Proposed Methods for Making Reliable Diagnostics Widely Available
Authors: Melander David , Sivarasu Sudesh , Yekinni Ibrahim , Yunzhang Cheng , Erdman Arthur
Published: January 2020

This paper proposes a structure and method for the development of an AI diagnostic system as a highly leveraged step toward improvements in delivery of healthcare in underserved regions. First, the paper provides a high-level, general review of the current efforts to provide healthcare services in underserved areas and the many efforts being made to impact health outcomes by various international, governmental, and NGO entities. We also very briefly review university programs and research institutions that have specific technical and institutional assets with significant potential to carry out research or to partially implement such a plan. Our review uses weighted values in a decision-system that takes in a variety of assets we consider fundamental to successful engagement in delivery of new, innovative, technology-enabled healthcare systems for under-resourced settings. We then review nine factors that hinder the advancement in healthcare in under-resourced settings, some of which are well described in current literature and some that may bring new perspectives. The paper then attempts to review how a proposed system can manage to operate successfully within the context of the nine named hindrance factors. The primary focus of the paper is in the description of a system which can increase the availability of diagnostics through technology-enabled systems. Such a system would impact the outcomes of persons in underserved regions. The paper then describes why making diagnostics available is a critical priority among efforts for improvements in global health.
An Approach to Robotic Testing of the Wrist Using Three-Dimensional Imaging and a Hybrid Testing Methodology
Authors: Badida Rohit , Garcia-Lopez Edgar , Sise Claire , Moore Douglas C. , Crisco Joseph J.
Published: January 2020

Robotic technology is increasingly used for sophisticated in vitro testing designed to understand the subtleties of joint biomechanics. Typically, the joint coordinate systems in these studies are established via palpation and digitization of anatomic landmarks. We are interested in wrist mechanics in which overlying soft tissues and indistinct bony features can introduce considerable variation in landmark localization, leading to descriptions of kinematics and kinetics that may not appropriately align with the bony anatomy. In the wrist, testing is often performed using either load or displacement control with standard material testers. However, these control modes either do not consider all six degrees-of-freedom (DOF) or reflect the nonlinear mechanical properties of the wrist joint. The development of an appropriate protocol to investigate complexities of wrist mechanics would potentially advance our understanding of normal, pathological, and artificial wrist function. In this study, we report a novel methodology for using CT imaging to generate anatomically aligned coordinate systems and a new methodology for robotic testing of wrist. The methodology is demonstrated with the testing of 9 intact cadaver specimens in 24 unique directions of wrist motion to a resultant torque of 2.0 N·m. The mean orientation of the major principal axis of range of motion (ROM) envelope was oriented 12.1 ± 2.7 deg toward ulnar flexion, which was significantly different (p < 0.001) from the anatomical flexion/extension axis. The largest wrist ROM was 98 ± 9.3 deg in the direction of ulnar flexion, 15 deg ulnar from pure flexion, consistent with previous studies [1,2]. Interestingly, the radial and ulnar components of the resultant torque were the most dominant across all directions of wrist motion. The results of this study showed that we can efficiently register anatomical coordinate systems from CT imaging space to robotic test space adaptable to any cadaveric joint experiments and demonstrated a combined load-position strategy for robotic testing of wrist.
The Influence of Tooth Surface Wear on Dynamic Characteristics of Gear-Bearing System Based on Fractal Theory
Authors: Li Xiaopeng , Xu Jinchi , Yang Zemin , Chen Renzhen , Yang Hexu
Published: January 2020

In this paper, the influence of tooth surface wear on dynamic characteristics of the gear-bearing system is discussed. The gear-bearing system considering the factors of tooth surface friction, time-varying meshing stiffness, backlash and et al. is established. Based on the Fractal theory and the Archard theory, the tooth surface wear is calculated, and it is substituted into the calculation of backlash and stiffness to obtain the time-varying backlash and the time-varying meshing stiffness. The Runge–Kutta method is used to solve the dynamic differential equation of the gear system, then the phase diagrams, the Poincare section diagrams and the bifurcation diagrams of the system are obtained. The results show that compared with the constant backlash and normal-distribution backlash under the wear condition, the wear backlash calculated by the Fractal theory and the Archard theory can better show the influence of wear on the system response. With the increasing of the accumulated wear on the tooth surface, the decrement of the time-varying meshing stiffness increases, and the system is more unstable. As the friction coefficient decreases, the regions of periodic and quasi-periodic motion state increase, and the boundaries between the periodic and quasi-periodic motion state become clear. Therefore, friction mainly plays a hysteretic role on the gear-bearing system.
Influence of Rectangular Ribs on Exergetic Performance in a Triangular Duct Solar Air Heater
Authors: Nidhul Kottayat , Kumar Sachin , Yadav Ajay Kumar , Anish S.
Published: January 2020

Several artificial roughness (ribs) configurations have been used in flat plate solar air heaters (SAH) in recent years to improve their overall performance. In the present work, energy and exergy analyses of rectangular ribs in a triangular duct SAH for varying relative rib heights (e/D = 0.02–0.04), relative rib pitches (P/e = 5–15), and rib aspect ratios (e/w = 0.5–4) are evaluated and compared with smooth SAH. The analysis reveals that the entropy generated due to heat transfer is lower for the ribbed triangular duct compared to the smooth duct. It is also observed that the width of the rib plays a crucial role in minimizing heat losses to the environment. A maximum reduction of 43% and 62% in exergy losses to the environment and exergy losses due to heat transfer to the fluid is achieved, respectively, with a rib aspect ratio (e/w) of 4 compared to the smooth plate. It is found that in contrast to the smooth plate, ribs beneath the absorber plate effectively improves thermal and exergetic efficiency. Maximum enhancement of 36% and 17% is obtained in exergetic efficiency (ηex) and thermal efficiency (ηth), respectively, for e/w = 4, P/e = 10 and e/D = 0.04. Results also show the superiority of the ribbed triangular duct over the ribbed rectangular duct for an application requiring compact SAH with a higher flowrate.
Cosine Error Elimination Method for One-Dimensional Convex and Concave Surface Profile Measurements
Authors: Guo Xiangyu , Han Jaemin , Lee ChaBum
Published: January 2020

This paper presents a novel method to eliminate cosine error in precision concave and convex surface measurement by integrating a displacement probe in a precision spindle. Cosine error in surface profile measurement comes from an angular misalignment between the measurement axis and the axis of motion and negatively affects the measurement accuracy, especially in optical surface measurements. A corrective multiplier can solve this problem for spherical surface measurement, but cosine error cannot be eliminated in the case of complex optical surface measurement because current tools do not measure such surfaces along the direction normal to the measurement plane. Because the displacement probe is placed on the spindle axis, the spindle error motion will affect the shape precision and surface roughness measurement of optical components such as mirrors and lenses, and the displacement probe will measure a combination of the spindle error motion and the geometry of optical surfaces. Here, the one-dimensional concave, convex, and hollow measurement targets were used, and cosine error was fundamentally eliminated by aligning the probe on the spindle always normal to the measured surface, and compensation was made for the aerostatic bearing spindle rotational error obtained by the reversal method. The results show that this proposed measurement method cannot only eliminate cosine error but also scan the large area quickly and conveniently. In addition, measurement uncertainty and further consideration for future work were discussed.
Improving the Surface Characteristics by Employing FSP on the Composites for the Automobile Brake Pad Application
Authors: Ashwath P. , Anthony Xavior M. , Rajendran R.
Published: January 2020

Looking at the background of the recent research on the area of the brake friction materials, composites are gaining the trust in being a potential replacement among the automobile sectors. The fabrication of the AA 2024 composites reinforced with 3 wt % Al2O3 is done using powder metallurgy technique followed by hot extrusion process. Current research work focuses on friction stir processed surface modified composites evaluated for the replacement of the currently used brake pads materials in automobile sectors. Surface characterization is carried out on the worn-out tracks of both brake materials developed and the counterpart employed using scanning electron microscope and XRD. The counterpart used in pin on disc configuration is exactly the material used in the automobile application (i.e. automobile brake disc plate material). Impact characteristics and tensile studies after friction stir processing (FSP) is studied as well. Coefficient of friction and wear loss characteristics in aspect of the tribological life of the composites developed is compared with the existing automobile brake pad components and found that FSP on composites served the purpose of the materials used in existing brake pads material.
Verification and Validation of a Homogeneous Reaction Kinetics Model Using a Detailed H2-O2 Reaction Mechanism Versus Chemkin and Cantera
Authors: Alam Shah Saud , Depcik Christopher
Published: January 2020

Increased black-box software use without adequate software literacy can lead to improper results and potentially disastrous consequences. Furthermore, such software is often expensive and comes with limited flexibility making it prohibitive for learning purposes. Therefore, this effort highlights the development of an adaptable, user customizable, and free open-source software tool to evaluate reaction kinetics in combustion models. Here, the software undergoes verification and validation to ensure proper operation over the intended domain of its application. The conceptual model is derived from the basic governing equations of thermodynamics simulating zero-dimensional constant pressure combustion with chemical kinetics based on a homogeneous hydrogen-oxygen reaction mechanism. Then, the computerized model is developed using a top-down programming technique for quick identification and elimination of coding errors. Operational validation occurs by comparing results with Chemkin and Cantera that reveals absolute and relative tolerances of 1E−12 and 1E−3, respectively, are sufficient for convergence at all specified initial conditions. In addition, the open-source software is computationally less intensive with average time savings of 33.69% and 48.88% versus Chemkin and Cantera, respectively. Subsequently, model results are time-shifted to the 50% fuel-burned mark and compared with experimental results for validation. This ensures that the created software is correct and useful for classroom instruction. Finally, the customizability of the open-source software instills confidence in students to develop custom chemical reaction mechanisms.
Investigating the Flowfield Physics Within Compressible Turbulent Boundary Layers
Authors: Ferguson Frederick , Feng Dehua , Gao Yang
Published: January 2020

Predicting the velocity, the temperature and the heat transfer rates within compressible boundary layers remains a challenging problem. Under compressibility and high Reynolds conditions, the density variations become very significant, resulting in high heat transfer rates. The net result is an altering of the dynamics within the boundary layer that is significantly different from its laminar counterpart. Physical properties, such as the specific heat capacities, the viscosity and the thermal conductivity, which are often considered constant, now vary with respect to temperature, creating a strong coupling between the velocity and the temperature fields. Despite the progress made in this field of research, a common issue frequently expressed in the literature is the difficulty in acquiring high quality time-resolved velocity and temperature data in compressible flows, especially near the wall. The major objective of this study is to demonstrate the capabilities of the Integral-Differential Scheme (IDS) by solving the flow field challenges within compressible boundary layers. It was demonstrated that IDS have the capability of accurately solving the full Navier-Stokes equations under realistic conditions. In the case of the compressible boundary layer, the IDS capture the flow field physics. However, it was demonstrated that the IDS is highly sensitive to grid resolution as well as the prescribed boundary conditions.
Modified Nernst-Plank-Poisson Model for IPMC With Back-Relaxation Effects
Authors: Al-Allaq Aiman , Jaksic Nebojsa , Ansaf Bahaa , DePalma Jude , Duong Trung
Published: January 2020

The ionic polymer–metal composite (IPMC) is a new practical engineering material that, it has a wide range of capabilities in both dry and liquid environments. IPMC is a new candidate for diaphragms in micropump devices, micro and Nano robotic applications. IPMCs are regarded as a capable actuator for transportable applications, however, the unique combination of electrochemical and mechanical properties that they possess, such as back-relaxation, restraint their use in real-life applications. There have a lot of attempts to understand and model the IPMCs properties and build a whole prototype that can be used, with certainty, in different robotic, control, and medical applications, yet, till now, it seems that the dehydration and back-relaxation are still not modeled properly.

The Nernst-Plank-Poisson was chosen to be the base model for the IPMC behavior, we were able to create a new model that truly represent the back-relaxation effects that occur in IPMCs, we’ve called the new model as modified NPP model. The modification used captured data from our experimental work Our modified analytical NPP (Nernst-Plank-Poisson) model was the verified using MATLAB & Simulink, which showed that the model, and the controller design for it was able to first compensate the loss of position of the IPMC due to back-relaxation, and then track the desired position input signals with great accuracy. The model and designed controller can be utilized in verity of robotic applications.
Seamless Coupling of Peridynamics and Finite Element Method in Commercial Software of Finite Element to Solve Elasto-Dynamics Problems
Authors: Wang Xiaonan , Kulkarni Shank S. , Tabarraei Alireza
Published: January 2020

Peridynamics formulation provides a strong tool for modeling of crack propagation. Although its ability to handle crack propagation is impressive it suffers from the drawback of high computational cost. In order to reduce the computational cost, peridynamics can be coupled with the finite element method. In this approach, peridynamics is used in critical areas where crack growth can happen and finite element formulation is used everywhere else. We use an Arlequin based coupling method to couple both peridynamics and finite element domain and implement the coupling approach in an existing finite element package. Initially, the user meshes the whole domain using finite elements. The software converts finite element mesh in the critical areas into peridynamics points. The proposed approach automatically creates a seamless coupling between the two regions. An example of a bar hitting a fixed plate is solved and compared with pure finite element results to prove the robustness of the method. Also, a problem of crack propagation under mixed mode loading is solved.
CFD Study of Generation Process and Stability of a Fire Whirl in Large-Scale Fires
Authors: Satoh Koyu , Viegas Domingos , Pinto Claudia , Tu Ran
Published: January 2020

Large-scale urban and forest fires, especially earthquake-induced fires may produce huge fire whirls and cause serious damage, due to the involved tornado-like strong wind, together with radiation and swirling flame. If fire whirls are generated, the danger to firefighters increases extremely. Many small-scale experiments and CFD simulations on fire whirls have already been conducted and also our previous numerical studies examined the generation of a large fire whirl in an oil tank. However, details of large-scale fire whirls have not been clarified yet. In this study, developing the previous works, additional CFD simulations are conducted to examine the generation process and particularly the stability of fire whirls. Three schemes to generate fire whirls are employed, using the 15 × 15 PMMA fuel array in windy conditions and n-heptane burning in a steel pan placed centrally on the floor in a tall channel with staggered four corner gaps, also using a channel with a single corner gap. The numerical results showed that the relationship between the fire area and the wind blowing area is important on the fire whirl generation in the PMMA scheme and n-heptane fire burning scheme in a channel. In addition to the channel gap size to produce a maximum fire whirl, the effects of channel height and horizontal channel area upon the fire whirl are examined. The wall temperatures of the channel are important to keep the swirling motion stably, particularly the wall temperature at about 300°C can stabilize the fire whirl in a channel. Also multiple small fires placed surrounding the central swirling fire can increase the stability of the fire whirl, although too strong multiple fires may destroy the stability. These phenomena may be related to the real fire whirl generation in the natural environment.
Design and Control of a Variable Geometry Hybrid Wheel-Leg
Authors: Artates Jonivan , Bahr Behnam
Published: January 2020

Conventional wheeled platforms provide sufficient locomotion on smooth surfaces but are limited when contending with obstacles such as stairs, steep inclines, or rugged terrain. Legged robots, which are better suited in traversing such obstacles, require an increased number of actuators, and thereby expend more energy. This paper describes the Adaptive Wheel-Leg, AWL, that provides mobile robots with the benefits of both wheels and legs. AWL is a two degree-of-freedom, hybrid wheel-leg topology with instantaneous switching between modes. AWL provides two modes: 1) a single actuator rolling mode for smooth surfaces, and 2) a walking mode for rugged terrain. This paper presents the mechanism’s design and control methods. An experimental model and a simulation of an AWL equipped hexapod are also discussed.
An Investigation Into Structural-Induced Noise in an Electric Motor
Authors: Vuong Tung Xuan , Li Willow Yangliu , Al-Jumaily Ahmed , Pandey Neel
Published: January 2020

The paper presents an investigation into the noise generated by structural vibration of an electric motor used in appliance products using Computational Simulation Approach. In particular, a 3-D numerical simulation model is specifically developed to predict the frequency response of the stator under three different simulation conditions: radial force only, tangential force only and the combination of both forces. The obtained data is used to analyze the acoustic generation in the far-field. Experimental is used to validate the predicted results. It shows the predicted results are very close to experimental results.
Nuclear Fusion Detection Methods for Use With IEC Machines
Authors: Pasmann Sam , Farina Jordan , Dillon Heather
Published: January 2020

Despite the potential for limitless clean energy, nuclear fusion is seldom discussed in conjunction with other alternative energy sources. Nonetheless, there is a small but strong amateur community dedicated to the research of nuclear fusion. If grown, this community may help facilitate more conversation, interest, and eventual research into nuclear fusion.

An often-large barrier in independent fusion research is detection and quantification of reactions. This research outlines the common methods currently used for fusion detection in inertial electrostatic confinement (IEC) reactors and suggests an experiment to explore indirect methods of detection using Matlab code written for light emission analysis. Current indirect, or theoretical, methods of determining reaction rate are unreliable, as they do not consider all construction variables of the reactor. By measuring characteristics of the plasma to determine reaction rate, a more accurate indirect measurement method may be developed, allowing for a larger number of individuals to participate in nuclear fusion research.
Quantifying the Stiffness of Biceps Muscle Using Accelerometer
Authors: Salman Muhammad , Palmer Alan , Iqbal Sajid
Published: January 2020

With increasing awareness of health benefits from incorporating exercise for a more physically active lifestyle, a natural increase in injuries to connective tissues within the body is inevitable. Determining the condition of these tissues by current imaging techniques is expensive, difficult, and not entirely reliable. Using a Modally Hand Impact Hammer and 3D accelerometers, shear wave propagation from surface vibrations of superficial skeletal muscle was measured. The use of accelerometers in this technique contribute some advantages over other techniques. The ability to mount the accelerometers directly to subject area provides greater flexibility for the subject and the investigator. Utilizing this method provides low cost, non-invasive, reliable and repeatable measure of material characteristics. An increase in shear wave propagation and Modulus of Elasticity were observed in 10 subjects as the number of excited muscle fibers within the biceps brachii increased (muscular contraction) and decreased lower than initial resting values post muscular contraction. This technique may prove more practical in clinical settings for swift in-house or on-site assessments of muscle stiffness to help determine the condition. In a broader relationship, this process further demonstrates that techniques developed through mechanical engineering are beneficial to the health and biology fields.
Stabilizing Ship Motion With a Dual System Inertial Disk
Authors: Storaas Torstein R. , Virkesdal Kasper , S. Brekke Gitle , Rykkje Thorstein , Impelluso Thomas
Published: January 2020

Norwegian industries are constantly assessing new technologies and methods for more efficient and safer maintenance in the aqua cultural, renewable energy, and oil and gas industries. These Norwegian offshore industries share a common challenge: to install new equipment and transport personnel in a safe and controllable way between ships, farms and platforms. This paper deploys the Moving Frame Method (MFM) to analyze ship stability moderated by a dual gyroscopic inertial device. The MFM describes the dynamics of the system using modern mathematics. Lie group theory and Cartan’s moving frames are the foundation of this new approach to engineering dynamics. This, together with a restriction on the variation of the angular velocity used in Hamilton’s principle, enables an effective way of extracting the equations of motion. This project extends previous work. It accounts for the dual effect of two inertial disk devices, it accounts for the prescribed spin of the disks. It separates out the prescribed variables. This work displays the results in 3D on cell phones. It represents a prelude to testing in a wave tank.
Phenomenon of Fog Formation and Flow Characteristics of Droplet-Vapor-Gas Mixture in a Cooler-Condenser
Authors: Gu Hongfang , Guo Qiwei , Li Changsong , Zhou Qing
Published: January 2020

Fog formation occurs in the process of condensation in the presence of non-condensable gas if the bulk temperature is lower than its saturation temperature (supersaturated). The phenomena of fogging is the formation of small condensate particles mixing with the vapor/gas stream, which creates potential problems of the vapor/gas/condensate separation and environmental pollution. Therefore, understanding of fogging mechanism and prevention of fog droplet entrainment are one of technical concerns for design and operation of cooler-condensers in the process industry.

This paper presents the experimental study and numerical simulation of shell-side condensation with fog formation using a mixture of steam/non-condensable gas. The experimental data were collected on the two tube bundles (modified plastic tubes and stainless steel tubes). Using a high-speed photograph technique, the phenomenon of fog formation and flow characteristics of vapor/droplet transport were recorded over a wide range of test conditions. The numerical analysis of film and dropwise condensation, fog formation and droplet particle transport were simulated using different tube geometry and material, and flow velocity of air/droplet mixture. Based on simulation results, a new droplet trapping parameter is proposed to assess the optimal parameters of heat exchanger structural and operation conditions. Comparisons show that the numerical analysis results have a good agreement with experimental data and observations. These findings provide fundamental approach to account for the effect of fog formation, film and dropwise condensation, and droplet transport crossflow in cooler-condensers.
Dual Gyroscope Wave Energy Converter
Authors: Korsvik Håkon B. , Rognsvåg Even S. , Tomren Tore H. , Nyland Joakim F. , Impelluso Thomas J.
Published: January 2020

This research models the energy extracted by gyroscopic wave energy converters. The goal is to assess the use of such devices to provide supplementary power to fish farms and lighting on oilrigs. This project implements the Moving Frame Method (MFM) in dynamics to model the power generated from a gyroscopic wave energy converter. The MFM leverages Lie Group Theory, Cartan’s moving frames and a new notation from the discipline of geometrical physics. This research extends previous work by incorporating two inertial disks to counter the inducement of yaw, and it improves the numerical integration scheme. Furthermore, this work makes use of a coherent data structure founded in the Special Euclidean Group, and it defines the initial disk spin as a prescribed variable. It accounts for the prescribed variables by modifying the equations of motion. Finally, it conducts an analysis of the generator moments. After obtaining the suite of descriptive equations of motion, this project integrates them using the Runge-Kutta method. Finally, a simplified 3D simulation is made using the Web Graphics Library to improve the readers’ intuitive understanding of the device.
Modelling the Motion of a 2-Arm ROV
Authors: Saure Marius R. , Iversen Sondre H. , Snekkevik Andreas B. , Gebhardt Rose , Chen Zhiyang , Mignano Christopher , Luchtenburg Dirk , Impelluso Thomas J.
Published: January 2020

Norway conducts operations on a variety of structures in the North Sea; e.g. oilrigs, monopole windmills, subsea trees. These structures often require subsea installation, observation, and maintenance. A remotely operated vehicle (ROV) can assist in these operations. Automation of intended motion is the desired goal. This paper researches the motion of an ROV induced by the motion of the robotic manipulators, motor torques, and added mass of fluid. This project builds upon a previous project that had one robotic arm; this time, there are two, but the method is unchanged. Furthermore, this work explores both the patterns in addressing such challenges, and an improved integration scheme. This research uses the Moving Frame Method (MFM) to carry out this project. In fact, this paper demonstrates the ease with which the MFM is extensible. Notable is that this work represents an international collaboration between an engineering school in Norway and one in the US. This work invites further research into improved numerical methods, solid/fluid interaction and the design of Autonomous Underwater Vehicles (AUV). AUVs beckon an era of Artificial Intelligence when machines think, communicate and learn. Rapidly deployable software implementations will be essential to this task.
Evaluate the Mechanical and Thermal Behavioural Deformation of Auxetic Composite Nano-Carbon Fibers
Authors: Oudah E. Al-Harbi Mohammed , Saleh M. Almansour Mohammed , M. Alomair Yousef Ali , Nabat B. Altulohi Fahad , Osman M. , Alarifi Ibrahim M.
Published: January 2020

This study aims to identify the composition of the pyrolysis products obtained through pyrolysis in the structure of different auxetic designs. Two design specimens of auxetic nano-carbon fibers with different directional load were fabricated, solid carbon fibers and hexagonal auxetic carbon fibers. The deformation behavior is well-known and has been analyzed. 3D finite element (FE) models were used to investigate both structures. There was some impact on the specimens used, and the behavior of the strain and stress line was captured. The main purpose of the experiment was to define and test the auxetic structure’s use in industries that require nano-carbon fiber material that has excessively good mechanical and thermal properties. In order to prevent the deterioration of the properties caused by this phenomenon, sizing of the yarns and bundles was carried out. Moreover, to form a sizing coating on the elementary fibers, DMA tests have been conducted, and both the thermal and mechanical properties investigated. In this case, the sizing agent must be in a sufficiently softened state. The compositions can improve nano-carbon vs the adhesion of the polymer matrix for auxetic nano-carbon fibers, which allows the use of such fibers for the reinforcement of plastics without extra processing.
Patient-Specific Mitral Valve Replicas for Preoperative Planning of Mitral Valve Repair
Authors: Kruttschnitt Michael , Hassan Nouray N. , Tiemann Klaus , Hitschrich Niklas , Sodian Ralf , Lueth Tim C.
Published: January 2020

Mitral valve regurgitation is one of the most common heart valve disorders and mitral valve repair is the favored therapy. For preoperative planning of the procedure, heart surgeons mentally interpret ultrasound images of the mitral valve. To improve preoperative understanding of the mitral valve and preoperative planning of the repair, we and other groups research patient-specific mitral valve replicas. The mitral valve is segmented from 3D ultrasound image data of the heart and a corresponding casting mold is designed and 3D printed. With it, the mitral valve replica is cast out of silicone. So far, segmentation and casting mold design are done manually. This makes the manufacturing of the mitral valve replicas laborious and complicates clinical application. We present patient-specific mitral valve replicas where the segmentation is semi-automatic and the casting mold design is completely automatic. We use an existing software that semi-automatically segments mitral valves from 3D ultrasound image data and developed an automatic casting mold design that automatically creates casting molds based on the segmented mitral valves. With this, patient-specific mitral valve replicas can be manufactured that may help heart surgeons to get a more precise understanding of the mitral valve preoperatively and to plan the most effective surgical repair technique. The automation should facilitate independent and mass clinical application. We equipped a heart clinic with our system and manufactured patient-specific mitral valve replicas for several patients. A heart surgeon planned mitral valve repair with them. We present one of the cases.
Design of a High Speed Internal Gear Pump to Increase the Power Density of Electro Hydraulic Actuators (EHA) in Mobile Applications
Authors: Pietrzyk Tobias , Roth David , Jacobs Georg , Katharina Schmitz
Published: January 2020

Increasing the rotational speed of the internal gear pump entails addressing topics such as cavitation, overheating and filling problems of the tooth spaces. Besides the development of a tooth geometry and flow optimization, using CFD simulation is necessary. This paper discusses the design of the newly developed high speed internal gear pump. This includes a detailed description of the different parts as well as the dimensioning of the pump by using CFD simulations. The geometry of the pressure build-up groove has a significant effect of pressure build up inside the pump. Therefore, three different geometries are investigated. The calculation of the journal bearings for the internal gear as well as for the driving shaft is shown. To avoid cavitation problems, the suction pressure of the pump will be increased up to 25 bar. This paper will show the technical arrangements to reach this high suction pressure level whilst still using a radial shaft seal ring. In order to determine the efficiency of the newly developed high speed pump, a test rig was built up. The test rig allows the measurement of the volumetric efficiency as well as the hydraulic-mechanical efficiency at different operation points up to 10 000 rpm and 250 bar.
A Lightweight Framework of R-LATs for Large-Scale Application
Authors: Jia Kang , He Ruihua , Fu Gang , Su Wenjun , Liu Zhigang
Published: January 2020

Rotate laser automatic theodolite system (R-LATs) is a distributed larger volume metrology system. With considering its excellent parallel measurement capability and the adaptive expansion of measureable space, R-LATs has a good prospect in large scale application, e.g. as a space measurement solution for an entire factory room to fix the spatial coordinate measurement, AGV navigation, and large component alignment etc. However, in large application scenario, where multiple theodolites are adopted, the photosensors suffer heavy working load in distinguishing the theodolite of each fan laser. It seriously restricts the real-time character, raises the probability of wrong signal generation, and degrades the work performance of R-LATs distinctly. To overcome this bottleneck, this paper proposed a lightweight framework for R-LATs to lighten the work load of photosensor in distinguishing the theodolites. Firstly, the working principle of R-LATs and the visibility of theodolite were introduced. Then, the whole frame work of R-LATs was designed in three aspects to relieve the work load of photosensor, i.e. topological network construction for entire R-LAT, data structure design for both compute terminal and photosensor, and the dynamic schedule of the data process unit for entire R-LATs. At last, by simulating AVG navigation in a large scale application of R-LATs, the effectiveness of this paper was proofed by comparing the computational loads with traditional configuration.
Enhancing Fractional Flow Reserve Procedure in Stenosis Diagnosis
Authors: Abuouf Yasser , Ookawara Shinichi , Ahmed Mahmoud
Published: January 2020

Stenosis is abnormal narrowing of blood vessels that causes a shortage in blood supply and a blockage of an artery Diagnosis of its severity guides the physician to determine the most appropriate treatment plan. Fractional flow reserve (FFR) is currently the most accurate procedure in stenosis diagnosis. It is a guidewire based technique that uses a small sensor on the tip of the wire to measure proximal and distal pressure of the stenosis. The difficulty of using such method is placing the guidewire precisely in centerline of blood vessel. Therefore, the main objective of the current study is to investigate how the measured pressure varies with the guidewire position. Accordingly, three different positions from the blood vessel centerline along with three degrees of severity are considered. The governing equations for blood flow are obtained and numerically simulated. Numerical results are validated using the available experimental and numerical data. A good agreement between predicted and measured values are obtained. Based on the predicted results, pressure drop coefficient (CDP) and pressure recovery factor (η) are computed. The predicted results with and without the effect of existing guidewire at different location are analyzed and the certainty of fractional flow reserve is reported and discussed. The current method is very helpful to increase the accuracy of fractional flow reserve procedure in stenosis severity estimation.
Mechanical Behavior of Thermosetting Polymers Undergoing High Strain-Rate Impact
Authors: Sable Peter , Borg John P.
Published: January 2020

A series of uniaxial and oblique flyer-plate impact experiments were conducted on fully dense, high durometer, polyurethane and epoxy formulations to investigate the high strain-rate dynamic material response. Samples were impacted at velocities ranging from 50 to 1,200 m/s at strain-rates of 105 – 106 s−1. The Hugoniot constants, yield strengths, and friction coefficients were inferred from velocity measurements taken from the back surface of the targets. Polymer Hugoniots were found to closely approximate those previously found in literature, with nonlinear curvature at low impact speeds due to viscoelastic effects. Strength behavior demonstrated pressure dependence which fit into a Mohr-Coulomb or Drucker-Prager yield surface criterion. Coefficients of friction between both epoxy and polyurethane, alongside a 7075-T6 aluminum tribological partner were quantified and results were used in conjunction with yield observations to hypothesize on the role of adhesion in high strain-rate shear of polymer-metal interfaces.
Low-Cost Particulate Detection in Bleed Air
Authors: Waez Mir Seliman , Eckels Steven J. , Sorensen Christopher M.
Published: January 2020

Bleed air is brought into aircraft cabins in order to maintain the quality of the air for passenger and crew health and comfort. The bleed air can be contaminated by oil due to oil seal leaks in the compressor which have been reported randomly and generated significant public interest. Previous studies have measured the particulate size distribution in the bleed air entering the cabin, but never distinguished the type and material of the particulate matter (PM). The particulates could be potentially hazardous oil droplets from the oil seal leaks, water droplets due the presence of fog generated by the cooling system, and so on. In this study we propose a novel technique using light scattering technology to distinguish between contaminant types. This technique uses size and complex index of refraction as the measure. Since each material has a distinct index of refraction, by determining the index of refraction, our proposed low-cost detector could distinguish the compound in the aerosol as well as determine the particle size simultaneously.
Clustering of Human Motion Trajectory for Lower Limb Rehabilitation Robot Design Based on Machine Learning
Authors: Zhao Kangren , Teng Zhiqiang , Gong Ningtao , Chen Fangkang , Zhao Ping
Published: January 2020

Lower limb rehabilitation robots, which usually produce repeated rehabilitative motion, not only simulate general human walking to help patients practice, but also do benefits to the remodel central nervous system to learn and store correct motion model. However, patients with different body parameters usually have different lower limb motion trajectories, and sometimes even the same person’s multiple motion trajectories could differ, thus the task of designing a specific lower limb rehabilitation mechanism for the realization of every motion trajectory is not practical. In this paper, we propose an approach to the clustering of motion trajectories of human lower limb to obtain a limited number of rehabilitation task motion types. Firstly, Gaussian distribution is adopted for the fitting of multiple trajectories of the same person. Through comparison of various clustering algorithms according to separation and compactness, Hierarchical clustering algorithm is chosen to obtain the partitions of the clusters. Finally, the Gaussian process regression (GPR) model of each cluster is established. Results show that clusters generated by this approach can reflect motion trajectory of the subjects and predict human lower limb motion pattern. With a limited number of lower-limb motion patterns, the design task of rehabilitation robots could be greatly simplified.
Comparing Electrowettability and Surfactants As Tools for Wettability Enhancement on a Hydrophobic Surface
Authors: Lokanathan Manojkumar , Sharma Himanshu , Shabaka Mostafa , Bahadur Vaibhav , Mohanty Kishore
Published: January 2020

Wettability alteration has significant applications in microfluidics, energy production and process engineering. Surfactants have been widely used for wettability alteration on surfaces. More recently, electrowetting (EW) has emerged as a powerful microfluidic technique to dynamically alter wettability. EW relies on the application of an electrical potential difference across a dielectric layer on which the fluid rests.

This work analyzes the extent of wettability enhancement of water droplets on a hydrophobic surface (in air) via the use of surfactants and EW. Nine surfactants were chosen from the categories of anionic, cationic and zwitterionic surfactants. The critical micelle concentration (CMC) of these surfactants, and the wettability of surfactant-infused water droplets was measured at post and pre-CMC concentrations. Next, experiments were conducted to quantify the wettability enhancement of water droplets (with surfactants) via EW.

Many interesting insights on the interplay between surfactants and electric fields are uncovered in this work. As expected, adding surfactants enhances wettability up to the CMC. EW can further enhance wettability of surfactant solutions and further reduce the contact angle by as much as 30°. Interestingly, it is seen that the influence of EW in enabling CA reduction is reduced by the addition of surfactants at pre-CMC levels. Conversely, surfactants strengthen the influence of EW at higher concentrations. It is noted that the extent of wettability alteration via EW is limited by the phenomena of contact angle saturation, wherein the contact angle saturates beyond a certain voltage. Interestingly, it is seen that at post CMC concentrations, the saturation contact angles are independent of surfactant concentrations.