bluuebunny/crossref_metadata_2025_split huggingface dataset:
Divers Augmented Vision Display (DAVD)
Authors: Manley Richard J. , Gallagher Dennis G. , Hughes William W. , Pilcher Allie M. 
Published: January 2018

Military diving operations are routinely conducted in what can be one of the most inhospitable environments on the planet, frequently characterized by zero visibility. The inability to clearly see the immediate operational environment has historically been a serious limitation to manned diving operations — whether the mission is ship husbandry, under water construction, salvage, or scientific research.
U.S. Navy diving is an integral part of the nation’s defense strategy with a continuing requirement to conduct manned intervention in the water column. To ensure technical superiority across the entire spectrum of diving operations we must identify, exploit, and de velop technology to advance the state-of-the-art in diving equipment. This can only be achieved by investing in, and supporting, focused research and development with specific goals to further diving capabilities.
Under a project sponsored by the Office of Naval Research (ONR) and Naval Sea Systems Command (NAVSEA), the Naval Surface Warfare Center-Panama City Division (NSWC PCD) has de veloped a prototype see-through head-up display system for a U. S. Navy diving helmet — the Divers Augmented Vision Display (DAVD). The DAVD system uses waveguide optical display modules that couple images from a micro display into a waveguide optic, translate the images through a series of internal reflections, finally exiting toward the diver’s eye providing a magnified, see-through virtual image at a specific distance in front of the diver. The virtual images can be critical information and sensor data including sonar images, ship husbandry and underwater construction schematics, enhanced navigation displays, augmented reality, and text messages.
NSWC PCD is the U.S. Navy’s leading laboratory for research, development, testing, evaluation, and technology transition of diver visual display systems; with unique facilities for rapid prototyping and manufacturing, human systems integration and extreme environment testing. Along with NSWC PCD, the Navy Experimental Diving Unit (NEDU), and Naval Diving and Salvage Training Center (NDSTC) are co-located tenant commands at the Naval Support Activity Panama City (NSA PC).
This paper provides a brief background on the development of diver head-up display systems, waveguide optical display technology, development of the DAVD prototype, results of diver evaluations, and recommendations for accelerated development of this game changing capability.
A Comparative Analysis and Evaluation of Model Selection Criteria
Authors: Kamel Ahmed H. , Shaqlaih Ali S. , Rozyyev Arslan 
Published: January 2018

The ongoing research for model choice and selection has generated a plethora of approaches. With such a wealth of methods, it can be difficult for a researcher to know what model selection approach is the proper way to proceed to select the appropriate model for prediction.
The authors present an evaluation of various model selection criteria from decision-theoretic perspective using experimental data to define and recommend a criterion to select the best model. In this analysis, six of the most common selection criteria, nineteen friction factor correlations, and eight sets of experimental data are employed. The results show that while the use of the traditional correlation coefficient, R2 is inappropriate, root mean square error, RMSE can be used to rank models, but does not give much insight on their accuracy. Other criteria such as correlation ratio, mean absolute error, and standard deviation are also evaluated. The Akaike information criterion, AIC has shown its superiority to other selection criteria. The authors propose AIC as an alternative to use when fitting experimental data or evaluating existing correlations. Indeed, the AIC method is an information theory based, theoretically sound and stable. The paper presents a detailed discussion of the model selection criteria, their pros and cons, and how they can be utilized to allow proper comparison of different models for the best model to be inferred based on sound mathematical theory. In conclusion, model selection is an interesting problem and an innovative strategy to help alleviate similar challenges faced by the professionals in the oil and gas industry is introduced.
Study of Gas Flow Through a Stirling Engine Regenerator
Authors: Rogdakis E. , Bitsikas P. , Dogkas G. 
Published: January 2018

In the present work, a three dimensional (3D) Computational Fluid Dynamics (CFD) analysis is applied to a designed small compact regenerator with specific porosity and wire diameter. The regenerator was studied as a part of a Stirling Engine designed in a simple way.
The gas temperature along the regenerator followed an approximately linear profile, while the metal temperature showed a small deviation during the engine cycle. The heat transfer coefficient between the gas and the matrix of the regenerator, along with the associate heat transferred were also derived. The heat exchanged in the regenerator is significantly higher to the respective heat in the engine’s heater and cooler.
Additionally, the pressure drop and the related energy dissipation are studied. Their variation is largely dependent on both mass flow-rate and working gas velocity. The friction factor coefficient for the designed regenerator is correlated with Reynolds number and an equation of two variables is derived.
Finally, the results of the CFD simulation are compared to those produced by a one-dimensional numerical model. These results include gas mass, mass flow-rate and Reynolds number, as well as the heat transferred between the gas and the regenerator matrix. Except for the case of the exchanged heat, the deviation between the two approaches is very small.
The Experimental Investigation of the Internal Support Effects on Exhaust Casing Pressure Recovery
Authors: Kalista Robert , Mrózek Lukáš , Hoznedl Michal 
Published: January 2018

As is well known, the performance of the last stage of the low pressure part of a steam turbine is strongly influenced by the effectivity of the downstream exhaust casing. The efficiency of the exhaust hood depends on many structural factors such as the design of the diffuser parts, dimensions of the outer casing or arrangement of internal supports. The aim of this paper is the experimental study of the influence of the internal supports of the axial-radial exhaust hood on its pressure recovery factor. For one geometry of its diffuser parts a few different variations of internal supports such as T-rib, tube grid or BV were tested. The effect of reducing the width of exhaust hood in the horizontal joint and the changing of axial length of the diffuser were observed. The width of exhaust hood in horizontal joint and the axial length of the diffuser define the area in the horizontal joint of the exhaust hood. How the diffuser behaves when reducing this area is very important in retrofitting of old machines, where there are so many geometric constrains. The effect of wall jet blowing into the diffuser wall was also evaluated. In this paper we concentrate to examine the sensitivity of these certain geometrical parameters of exhaust hood on the pressure recovery of the whole exhaust system of the low pressure part of the steam turbine.
The main purpose of our analysis and experimental measuring was optimising the axial-radial exhaust hood of the steam turbine. For this reason, wind tunnel facilities with relevant measuring and traversing systems were designed and built. The measurements have been performed on 1/5th scale test rig which enabled rapid and efficient evaluation of multiple geometrical variants. The observed exhaust hood was designed for an extra long 54inch last stage blade. For measurements of flow parameters was used multi-hole pneumatic pressure probes and wall pressure taps in conjunction with CFD tools to explore physics based alterations to the exhaust configuration.
ADI-CRSTS: A New Method for the Moving Heat Sources — Application to a Train Pantograph Strip
Authors: Delcey Nicolas , Baucour Philippe , Chamagne Didier , Wimmer Geneviève , Bouger Odile , Auditeau Gérard , Blanvillain Gérard , Bausseron Thomas 
Published: January 2018

The pantograph strip interface involves many physical phenomena. Temperature evolution is one of them. This problem includes various thermal flux and sources. More specifically, due to the train motion, a moving zigzag heat source occurs.
This paper deals with a thermal 2D Alternating Direction Implicit (ADI) numerical method for temperature estimations in the train pantograph carbon strip, the aims being a better wear problems anticipation and the creation of a preventive maintenance. For that, an electrical model is coupled to the thermal one to take into account all Joule effects.
The ADI strategy enables a significant computation time reduction against most classical resolution methods. Besides, the model involves two mathematical processes: the first one is an appropriate variable transform which induces a fixed surface heat production, while the second is based on locally refined meshes.
Various numerical tests are presented and discussed in order to show the accuracy of the scheme. From a physical point of view, the results are much interesting. Further investigations, depending on the different parameters, should lead us to predict the strip critical thermal phases.
Implementation of Additive Manufacturing Into Engineering and Engineering Technology Curriculum
Authors: Springer Scott L. , Johnson Jerome , Bushendorf Glenn 
Published: January 2018

Public universities have a responsibility to continuously improve instruction and maintain currency with new technological advances. Simultaneously many public universities are under budget constraints seeking to maintain or reduce costs. One recent technological advance is the adoption of additive manufacturing by an increasing number of manufacturing industries. While machine costs of additive manufacturing have dropped in recent years, machine and consumable material costs remain significant. Hence, there is a need in the manufacturing, engineering and technology education community for methods to introduce additive manufacturing concepts into the curriculum while doing so with a minimum required investment.
In this paper we discuss the methods used to implement additive manufacturing theory and applications into the Engineering and Engineering Technology curriculum at the University of Wisconsin-Stout. Applications of the additive manufacturing technologies have been successfully included in traditional courses covering sophomore level research and development, upper level computer-aided design, upper-level research and development, capstone courses, and the introduction of a new course focused on additive manufacturing. The implementation of commercial, low cost open-source hobbyist kits and new hybrid student designs of AM machinery is discussed, along with the process used to develop additive manufacturing equipment in the Advanced Manufacturing Lab.
Using a Six-Axis Articulated Robot Arm for Teaching Mechanical Engineering Students Software Development
Authors: Weber Moritz , Pitz Katrin , Anderl Reiner 
Published: January 2018

Software development is a key skill for all engineers and is therefore part of the first semester curriculum for mechanical engineering at Technische Universität Darmstadt (TU Darmstadt).
A new method in engineering studies at TU Darmstadt based on project-based learning is being introduced to give students the opportunity to gain experience in software development using MATLAB and controlling real world objects. In this project, a 6-axis articulated robot arm similar to the ones used in industrial applications is being used.
In addition to the motors used to drive the robot arm it is equipped with a color sensor. The students are thus encouraged to familiarize themselves with processing sensor data and incorporating it into their problem-solving approaches.
The students are given a newly developed virtual model of the robot also implemented in MATLAB, which enables them to develop and test their solutions even when there is no access to the physical robot.
To communicate with the robot the same methods for both the real and the virtual robot is provided to control the angles of the joints of the robot. As the students are only given Cartesian coordinates they have to convert these for the robot to use.
The task given to the students comprises the development of an algorithm to solve a specific problem using the robot, programming a graphical user interface and a documentation of the project’s results.
Students solve the given programming task in self-organized groups of four and undergo a team-based software project with focus on engineering from the beginning to the end. This allows them to reflect on personal competencies and to find their respective roles in a team at a very early stage of their studies. The project applies various aspects taught in the corresponding lecture and thereby emphasizes the practical use of the subject matter.
In the concluding presentation, the students are encouraged to reflect their work, summarize the results and show the special features of their implementation.
Methane Steam Reforming and Steam Injection for Repowering Combined Cycle Power Plants
Authors: Carapellucci Roberto , Giordano Lorena 
Published: January 2018

Repowering existing power plants represents a potential route to meet the increasing energy demand, in a context of more and more stringent environmental regulations, hindering the construction of new facilities. Conventionally, repowering is operated into existing steam power plants, thus allowing to increase the design capacity to such an extent that depends on the type of strategy to exploit the waste heat from the additional gas turbine.
In this study a new repowering concept is proposed. It involves the integration of an additional unit based on a gas turbine into an existing combined cycle gas turbine (CCGT). Based on this concept, two repowering options are examined. In the first one (Option A), the waste heat from gas turbine flue gases is used to produce steam in a one pressure level steam generator. In the second option (Option B), the exhaust waste heat recovery promotes the generation of a synthesis gas in a methane steam reformer. The integration of the additional unit is operated by the injection of superheated steam (Option A) and the reformed fuel (Option B) into the combustor of the main power plant, thus allowing for a further increase in power output of both topping and bottoming cycles. The simulation study allows to compare the repowering options with respect to the potential increase of power capacity, as well as in terms of energy marginal performance parameters.
Development of AC Magnetic Field Stimulation Bio-Reactor for Three-Dimensional Culture of PC12 Cells
Authors: Sakiyama Ryota , Matsumoto Kazuya , Yamamoto Koji , Morita Yusuke , Nakamachi Eiji 
Published: January 2018

Recently, the electromagnetic stimulation method to enhance a nerve axonal extension has been attracting a great attention in the nerve regeneration. In this study, we design and fabricate a new 3D bio-reactor, which can implement uniform AC magnetic field (ACMF) stimulation on PC12 cells. We observe the morphology of PC12 cells using the multi photon microscope and evaluate effectiveness of uniform ACMF stimulation of the nerve axonal extension and the neural network generation.
Firstly, a uniform ACMF stimulation bio-reactor was designed by using the pole piece structure. We searched an optimum structure using the magnetic field finite element analyses to obtain a uniform magnetic flux density in the culture region. Secondly, a chamber for 3D culture of PC12 cells was fabricated. PC12 cells were disseminated into a collagen gel which poured in the chamber. We evaluated the effects of uniform ACMF stimulation to enhance the nerve axonal extension. In our bio-reactor, an increase in axonal extension length and number of dendrites was observed under ACMF stimulation after 7 days culture. Finally, it was concluded that our uniform ACMF stimulation bio-reactor is an effective tool for the nerve axonal extension and the neural network generation.
Design for Manufacturing and Assembly (DFMA) of a Test Bench to Simulate Mechanical Vibrations in Rotating Equipment
Authors: Maradey Lázaro Jessica Gissella , Forero González Carlos Adolfo , Ovalle Silva Germán Andrés 
Published: January 2018

In the last decade, the reliability and safety of industrial processes have played a very important role in ensuring competitiveness of national and international companies, requiring on-line and off-line fault detection systems that appear in normal operation, and in other cases, the implementation of more robust methodologies for potential failures.
Two of the problems that usually occur in the rotary equipment are the mechanical misalignment and imbalance caused mainly by errors in the assembly, non-uniformity in the density of the material, tolerance in the manufacture of parts, which cause great damage in the machines and generating vibrations that cause problems such as heating parts, increased hot oil, increased lubricant dripping through seals, premature failure of bearings, seals, shafts and joints, wear and tear of parts, loss of efficiency in the engine, noise and collateral damage among others.
The results of this research provide guidelines for the design, manufacturing and assembly of a test bench to simulate misalignment and imbalance failures under controlled conditions by measuring and monitoring selected variables for study, take into account the benefits of Maintenance Condition Monitoring (CBM) and Design for Manufacturing and Assembly (DFMA) methodology.
The Influence of Sulci Trabeculae in Mitigating Impact Induced TBI
Authors: Hashemi Siavash , Anwar Sharlin , Mansoorbaghaei Shahab , Sadegh Ali M. 
Published: January 2018

Traumatic brain injury (TBI) is an intracranial injury caused by impacts or angular accelerations of the head such as a violent blow, a bump, a projectile, or even a blast. TBI is a major problem that accounts for over 1.4 million emergency room visits in US. Thus, it is important to understand and predict the occurrence of TBI. Previous studies have shown that the interaction between the subarachnoid space (SAS) trabeculae and the cerebrospinal fluid (CSF) plays an important role in damping the effect of impacts and reducing the brain injuries. However, the influence of sulci parameters and sulci trabeculae in impact induced TBI is still unexplored. A few studies have shown that inclusion of sulci in brain models alters the brain injuries conclusions, even though those models do not take into account the trabecular tissue present in the sulci.
In this study, to obtain a perspective of the morphology and architecture of the sulci trabeculae at the frontal lobe of the brain, Human cadaver brain of an 87 year old male was used. For the first experiment, several sulci from the frontal lobe were sectioned and measured to find the average sulci depth, using the image processing software called ‘ImageJ’. This experiment was followed by the Scanning Electron Microscopy (SEM) study on the samples prepared from the frontal lobe. Indeed, numerous images were taken at various magnifications to find different trabecular morphology and architecture in the sulci.
The results from the experimental studies were used in our numerical analyses. To do so, the validated global 3D FE model of the human head and neck, created at The City College of New York, were impacted by a rigid barrier on the forehead. The pressure time history, beneath the skull, was calculated during and after the impact. Moreover, a local 3D FE model has been created, having the meninges and the brain with sulci, including the trabeculae and the CSF. The depth of the sulci and the architecture of the trabeculae have been inspired by the imaging and SEM studies. Indeed, the top surface of the local model was subjected to the pressure loading condition obtained from the global model. The results of the finite element simulations reveal that the interaction between the trabeculae and the CSF inside the sulci, would affect and reduce the movement and displacement of gyri and sulci’s walls when the forehead of the head is impacted by an elastic barrier.
Hybrid Probabilistic Physics of Failure Evaluation of Reliability in MEMS Devices
Authors: Pourgol Mohammad Mohammad , Mobasher Moghaddam Minoo , Soleimani Morteza 
Published: January 2018

Reliability is critical in MEMS devices design and production. Probabilistic Physics of Failure is proposed in this research for evaluation of MEMS devices reliability. Failure mechanisms are evaluated for determining the most common failures. Accordingly, a deterministic model is selected for the analysis of the life and reliability for the dominant failure mechanisms. By identification of the uncertainty sources affecting dielectric lifetime, the deterministic model is converted to a probabilistic model. This model is simulated by utilization of the Monte Carlo method. The result of life estimation is then updated using the Bayesian method.
As a case study, a framework is developed for reliability evaluation of the MEMS devices with capacitive RF MEMS switches. Results of FMEA show that stiction caused by dielectric charging, is the main failure mode in RF MEMS capacitive switches due to the presence of a high electric field across the dielectric and existence of point defects in these materials. Finally, the results of life estimation are updated using the Bayesian method.
Bioactive Coating From White Portland Cement Deposited by Pulsed Laser Deposition
Authors: Fialkova Svitlana , Yarmolenko Sergey , Sankar Jagannathan , Ndungu Geoffrey , Wilkinson Kevin 
Published: January 2018

Objective. We report the study of feasibility to produce the thing bioactive coating from experimental dental cement using pulsed laser deposition (PLD) technique.
Methods. The targets for PLD system (disks 30 mm in diameter × 5 mm thick) were sintered from micronized powder of set Alborg White Portland cement (WPC). The parameters for sintering process were chosen based thermo-gravimetric analysis and differential scanning calorimetry (TGA/DSC). The coatings were deposited by PLD on silicon substrates. The effect of laser power on coating crystallinity and morphology was evaluated by scanning electron microscope (SEM) and X-ray diffraction (XRD). The material transfer from target to substrate were evaluated by X-ray fluorescence (XRF) and X-ray energy dispersive spectroscopy (EDS).
The bioactivity of deposited films was evaluated by ability produce the hydroxyapatite (HA) layer on a surface of specimen immersed in a simulated body fluid (Dulbecco’s Phosphate-Buffered Saline (DPBS). The formation of hydroxyapatite was confirmed by SEM, X-ray energy dispersive spectroscopy (EDS), XRD and micro-Raman spectroscopy. The formation of HA was evaluated after 1, 3, 7, 14, and 21 days of immersion. Results. This study demonstrated that White Portland cement can be used as a target material for manufacturing of bio-functional coatings. The films deposited on Si substrates have mainly amorphous structure; the crystallinity of the film can be achieved by increasing the laser power. The biological performance of deposited films was tested by HA forming ability in simulated body fluid. The HA layer was formed on a coated surface after first day of immersion.