bluuebunny/crossref_metadata_2025 huggingface dataset:
Flow Characteristics of a Multiple-Cell Pump Basin
Authors: Dornaus W. L.
Published: January 2022

Variations of the flow pattern in a pump-suction pit containing a variable number of pumps in operation are of interest in studies to determine the most economical pumping structure. The use of a one-to-ten scale model of a large pumping plant gives quick and relatively inexpensive answers to questions concerning proper pump submergence, spacing, influence of baffling, and mechanical appurtenances such as screens and gates, and the relative influence between two or more pumps with various numbers of units operating together. Visual effects for flow observation make positive analysis fairly simple. Use of Froude’s law in this investigation confirms results of previous experimenters and simplifies test procedure.
Symposium on Welded Spiral Cases from the Consulting Engineers’ and Users’ Viewpoint: TVA Experiences, Welded Versus Riveted Spiral Cases
Authors: Gardner R. M.
Published: January 2022

This paper describes erection and welding procedures carried out on Fontana, Hiwassee, and Watauga Units of the Tennessee Valley Authority, and gives erection costs of both welded and riveted cases where such costs are comparable.
Symposium on Welded Spiral Cases from the Consulting Engineers’ and Users’ Viewpoint: Pressure-Embedment of Spiral Cases
Authors: Seitz Bradley G.
Published: January 2022

It is the practice of the Bureau of Reclamation to pressure-test hydraulic-turbine spiral cases in the field at case-design pressure and to embed them under normal operating pressure. This paper gives reasons why this practice was adopted and describes some of the methods used.
Blowdown and Charging Processes in a Single Gas Receiver With Heat Transfer
Authors: Reynolds W. C. , Kays W. M.
Published: January 2022

Gas blowdown and charging processes are generally analyzed on the basis of an adiabatic thermodynamic process. In most such processes of technical interest there is a considerable amount of heat transfer between the gas and the container walls, and in some applications heat capacitors are deliberately inserted in the container to control temperature or store thermal energy. In this paper the general problem of blowdown and charging is considered, including the effects of heat transfer to or from container walls or inserted heat capacitors. An experimental investigation of blowdown with heat transfer is described, and it is shown that the results correspond very well with the analysis.
The Propagation of Cracks and the Energy of Elastic Deformation
Authors: Bueckner H. F.
Published: January 2022

The Griffith-model of brittle fracture of elastic solids and the model by Irwin and Orowan for the brittle fracture of elastic-plastic solids predict the propagation of cracks on the basis of energy supplied by the work of externally impressed forces and by the change of strain energy. Previous discussions have neglected the three-dimensional viewpoint and the body forces. Since the Irwin method of fracture-strength analysis has become of increased interest, especially with respect to rotor fracture, a general analysis of energy supply is presented. The analysis uses Clapeyron’s theorem and Betti’s reciprocal theorem. One of the results is that the energy supplied for crack extension equals the strain energy of the difference of the two stress fields before and after crack extension.
A Simple Method of Estimating the Reynolds Number Effects on Aircraft Gas-Turbine Engines Operating at High Altitudes
Authors: Pinnes Robert W.
Published: January 2022

At present, the altitude performance of an aircraft gas-turbine engine is usually estimated by generalizing sea level data. Sufficient altitude test data have now been obtained to demonstrate that this method is not entirely valid. One of the primary reasons for the deviations from the generalized data is the Reynolds-number effect.

In this paper, an attempt is made to establish a simple method for estimating correction factors for these Reynolds-number effects, for both turbojet and turboprop engines. These correction factors are based on an empirical correlation of some available test data by means of an “effective Reynolds-number diameter” parameter.

The paper (a) discusses the general problem, (b) reviews the available test data, and (c) recommends correction factors for each of the cases considered. In the last analysis, an altitude calibration of each specific engine is still required to establish accurate altitude data. However, in the absence of any better information, the curves established herein may be used to provide some preliminary estimates.
Prediction of Creep in Bending from Tension- and Compression-Creep Data When Creep Coefficients Are Unequal
Authors: Findley W. N. , Poczatek J. J. , Mathur P. N.
Published: January 2022

The method of predicting creep in bending from data on creep in tension previously described has been extended to the prediction of creep in bending when the creep in tension and compression are unequal, and when the time-dependent and time-independent stress functions are unequal. It was shown that the stress distribution and position of the neutral axis in a beam changed with time when the creep in tension and compression were unequal; and the stress distribution changed with time when the time-dependent and time-independent stress functions were unequal. Computed creep deflections were compared with available data on canvas laminate and polystyrene, with good results for the former and fair results for the latter.
Analysis of the Effect of Pulsations on the Response of Mercurial-Type Differential-Pressure Recorders
Authors: Martin R. J. , Moseley D. S.
Published: January 2022

Low-frequency periodic pressure pulsations are sometimes encountered in gas pipelines. These pulsations may cause oscillation of the recording pens of orifice meters, making a true reading of gas flow difficult. In this paper, general equations describing the response of the mercurial-type differential-pressure recorder to such pulsations are developed. For the purpose of this paper the system of equations is then linearized and a specific solution is presented.
Development of the Generalized Phase-Diagram Method
Authors: LeFevre P. M.
Published: January 2022

The present study is concerned with the stability of linear systems with real coefficients. The author reviews the graphical method of the generalized phase diagram worked out in 1949, in collaboration with Mr. Demontvignier, and presents a new rule for interpreting the phase diagram.
On the Economics of the Basic Turning Operation
Authors: Brewer R. C.
Published: January 2022

The general economic problem of turning is fairly well appreciated from a qualitative viewpoint; viz., that the reduction in machining cost as the cutting speed is increased will be eventually more than offset by increased tool changing and grinding costs. The problem involves, however, a great number of variables and it must be conceded as axiomatic that the number of variables which can be conveniently handled mathematically is such that a great deal of generality is lost. There is a further risk of loss of generality in attempting to represent the mathematical results in a form suitable for application, preferably graphical. This paper attempts to achieve the initial goal of including at least the fundamental variables in the analysis and representing the results in a reasonably useful form.
“DeCew Falls, Abitibi” Turbine Tests
Authors: Aeberli A. E. , Walker R. A.
Published: January 2022

This paper describes the results of Gibson tests for efficiency and performance of the DeCew Falls, Abitibi Francis turbine. This turbine was installed initially at the Abitibi Canyon station to operate under 237-ft head and was later removed and reinstalled at a new site in the DeCew Falls station to operate under 280-ft head. A comparison is developed to show the results “expected” at DeCew Falls from the original Abitibi tests versus the actual field test results obtained at DeCew Falls.
Symposium on Laboratory Testing of Hydraulic Turbine Models in Relation to Field Performance
Authors: Petersen H. J. , Crowe G. F. , Rheingans William J. , MacNamee William R. , Sproule Robert S. , VanderBoegh Bruce L. , Johnson G. Dugan
Published: January 2022

This report includes, in full, the five prepared statements by representatives of the major American manufacturers and, in condensed form, the written and oral discussions presented at the 1956 Annual Meeting. These discussions have been condensed by Mr. G. Dugan Johnson, the 1956 Chairman of the Hydraulic Prime Movers Subcommittee, to reduce the over-all length of this publication and have not been edited by the respective authors. Therefore they may not reflect the intended and fully considered opinion of the parties quoted and where this is the case these authors are particularly requested to submit written discussions, correcting or appending this record. The Summary has also been prepared by Mr. Johnson and reflects his personal and tentative summation of the points on which the panel members and discussers appear to him to agree. It is offered as a basis for discussion at the 1957 Annual Meeting, particularly by each panel member and discusser quoted in this report.
Effective and Local Surface Coefficients in Fin Systems
Authors: Dusinberre G. M.
Published: January 2022

When tests are made on systems containing extended heat-transfer surface, the direct result is an “effective” surface coefficient. The desired result is a ‘local” or true surface coefficient. This paper shows how, on reasonable assumptions, the one can be calculated from the other without trial-and-error procedures.
Vibration and Shock in Freight Cars as Causes of Lading Damage
Authors: Settles James C.
Published: January 2022

The high costs resulting from merchandise damaged in railway freight transit in recent years indicate a need for improvement and justify major changes in equipment design where necessary to meet the requirements of present operating conditions. Vibration and shock are two probable causes of lading damage. These two problems are analyzed briefly and on the basis of the findings methods are suggested for improving equipment design to reduce damage to both lading and equipment due to these two causes.
Treatment of Make-Up Feedwater, Condensate, and Recycle Water for Supercritical and Nuclear-Reactor Power-Plant Cycles
Authors: Calise V. J. , Duff J. H.
Published: January 2022

This paper presents a comprehensive view of the experience and practical knowledge, as well as the thought and advanced ideas employed in treatment of water in such power plants of the future as the supercritical and nuclear power stations. An attempt is made to show where pioneering engineering and scientific developments are being applied with little practical long-range experience to support them. Nevertheless the frontiers of power-plant water-treatment engineering are being advanced and we believe that the next few years will show substantial accumulation of actual performance data useful to power-plant designers of the future.
The Use of Adjustable-Stator Blades to Reduce the Idle Fuel Flow of a Simple-Cycle, Single-Shaft Gas Turbine
Authors: Howard C. , Hendrickson R. L.
Published: January 2022

A simple-cycle, single-shaft, gas-turbine power plant has been tested with adjustable compressor-stator blading to investigate this method of reducing idle fuel flow. This paper discusses the factors affecting idle fuel flow, and presents results of power-plant tests with several stator geometries.
Dynamic Analysis of a Boiler
Authors: Chien K. L. , Ergin E. I. , Ling C. , Lee Allyn
Published: January 2022

Dynamic analysis of a boiler is accomplished by certain approximations which reduce the nonlinear partial differential equations to linear ordinary time-differential forms, and make it possible to obtain the time-dependent functions of large numbers of boiler variables. Linear equations thus obtained are solved by means of an electronic differential analyzer and open-loop response of drum pressure and water level for various input variables (feed-water rate, fuel-flow rate, and steam-flow rate) are shown as examples. A linearly controlled response of the same boiler is also given as an example of the flexibility of the method and the analog solution. It is shown that the potentiality of the method is not limited to this initial study, but can be extended for greater accuracy with the availability of machine computation. Analog simulation of the boiler also makes it possible to investigate the effects of the boiler physical dimensions, heat, or mass-transport constants and to verify some of the basic assumptions on the dynamic behavior of the over-all system.
Continuous Measurement of Characteristics of Systems With Random Inputs: A Step Toward Self-Optimizing Control
Authors: Goodman T. P. , Hillsley R. H.
Published: January 2022

To achieve self-optimizing control, a signal which reflects changes in system dynamics must be available to actuate controller adjustments. In this paper a new technique is presented whereby changes in system parameters are detected from changes in the moments of the system impulse response. At the same time, changes in input statistical properties are detected by changes in the moments of the input autocorrelation function. Recent investigations by Paynter and others have shown the importance of impulse-response moments as a means for characterizing the dynamics of a system. By the technique described in this paper, these moments are determined continuously and directly from the random variations in the system input and output, without passing through the intermediate steps of obtaining the input-output correlation functions and the system’s impulse or frequency response. The precision of measurement of the moments can be estimated statistically, so that the design specifications for the equipment required for any desired precision of measurement can be established. The new technique has been applied experimentally to a simple linear system with promising results.
Tacit Knowledge Capture Using Digital Tools in a Human-Robot Interaction: A Case Study
Authors: Guerra-Zubiaga David A. , Nasajpour-Esfahani Navid , Phan Ngan Q. , Gupta Shalu , Block Logan
Published: January 2022

Industry 4.0 is considering a new industrial revolution with important advanced manufacturing paradigms connected. This paper explores the capture of tacit knowledge using digital tools and a robotic mechatronic case study. Digital manufacturing tools have been used to simulate complex human-robot interactions, and it is important to capture said tacit knowledge to create next generation automation systems. This research uses a tacit knowledge lifecycle to capture key mechatronics experiences using a digital twin. The research hypothesis is that capturing mechatronic tacit knowledge through digital twins could support the creation of a new and more complex next generation automation system.
Simulation-Based Correlation for Saved Energy in Ground Source Heat Exchangers for Middle East Region
Authors: Ahmed Khaled I. , Almashhor Abobakr , Ahmed Mohamed H.
Published: January 2022

Shallow geothermal energy is a renewable energy source used to reduce electric demand to produce cooling and heating of buildings. The temperature at a specific ground level is constant year-round depends on the geographic region. It can be utilized by exchanging heat in the hot weather (cooling) or cold weather (heating) using Ground Source Heat Exchangers GSHE. Many attempts have been proposed to investigate the GSHE controlling factors with a lack of interconnection effects of mutual inclusive parameters.

The current work investigates the interconnection relation of seven factors; three geometrical factors, two thermophysical factors, and two operational and environmental factors. The studied geometrical factors are the wellbore diameter and length and the tube diameter. The thermal conductivities of the wellbore grout and soil are the studied two thermophysical properties. The two studied operational and environmental factors are the circulating fluid flow rate, circulating fluid input temperature difference with the soil temperature.

A 2D axisymmetric CFD model is built to investigate the effect of the controlling parameters on the targeted output saved energy per tube length. Third-order surface response of the main output is achieved using a hybrid Box-Behnken Central-Composite design of experiments methods DOE. The Box-Behnken method concerns the mid of extremes, and the Central-Composite method concerns the rotatable variable interconnections. Although both methods are designed for second-order response surfaces, the proposed hybrid method can accurately predict third-order correlation using the Stepwise regression method on 136 design points. The nonlinear correlation is verified using another 100 random verification points, showing a root mean squared error of less than 1.5 [W/m].

The significance of each parameter on the target normalized saved energy is presented and discussed. The pipe diameter, grout conductivity, soil conductivity, and temperature difference are the most significant parameters controlling the GSHE performance. The water mass flow rate is lesser significant, while the grout diameter is insignificant. The response surface study has shown high normalized saved energy of 100 [W/m] of the pipe length for the investigated domains.
Bifurcation Characteristic and Energy Transfer of Vehicle Shimmy System Considering the Coupling of Vertical and Lateral Dynamics
Authors: Wei Heng , Lu Jian-Wei , Lu Hang-Yu , Ye Sheng-Yong
Published: January 2022

Since the vehicle is a complex mechanical system with many subsystems, the influence of the dynamic coupling between the subsystems of the vehicle on shimmy should be taken seriously. Therefore, a 12 degrees-of-freedom dynamic model of vehicle shimmy system with consideration of the dynamic coupling between the vertical motion and the lateral motion of the vehicle is established. In particular, the influence of the vertical load of the tire on the nonlinear cornering force is also considered. Then, the dynamic stability of the shimmy system is discussed with the help of the system eigenvalues, and the influence of the damping of the front suspension on the dynamic stability is also examined from the viewpoint of the energy transfer. On this basis, the damping of the front suspension is selected as a bifurcation parameter, and the two-dimensional center manifold of the high dimensional shimmy system is obtained by means of the center manifold theory. Finally, the Hopf bifurcation characteristic of the shimmy system is analyzed, and the analytical solutions of the shimmy system are derived for different damping of the front suspension. The results show that the increase of the damping of the front suspension is beneficial to attenuate vehicle shimmy and improve the dynamic stability of the vehicle.
Supercritical Carbon Dioxide Power Cycle Integrated With Solar Power Tower and Oxy-Combustor
Authors: Sleiti Ahmad K. , Al-Ammari Wahib A. , Gamil Ahmed I. , Al-Khawaja Mohammed
Published: January 2022

Power cycle that integrates solar power tower (SPT) system with direct oxy-combustion (DOC) supercritical CO2 cycle is proposed and investigated. In the SPT/DOC-sCO2 cycle (Cyc 3), the SPT works as preheater for the DOC/sCO2 system. Two more basic cycles for comparison and validation purposes are investigated including stand-alone intercooled sCO2 power cycle driven by DOC system (Cyc 1) and stand-alone basic SPT system (Cyc 2). Energy, exergy, exergoeconomic, levelized cost of electricity (LCOE) and multi-objective optimization analyses are performed for each cycle over wide range of operating pressures, temperatures and direct normal irradiance. Compared to Cyc 1 and Cyc 2, Cyc 3 has higher thermal efficiency by 6% and 2%, respectively with higher exergy efficiency and is less sensitive to cycle minimum temperature. However, the LCOE of Cyc 3 is higher due to the large capital cost of its individual CSP and DOC systems. From the optimization analyses, it is found that the decision variables of the three cycles tend toward low Pmax, higher Pmin, lower Tmax, and lower Tmin. The multi-objective optimization shows that the thermal efficiency and LCOE are 41.06% at 6.35¢/kWh for Cyc 1, 45.56% at 7.86¢/kWh for Cyc 2, and 46.65% at 8.05¢/kWh for Cyc 3.
Regional Strain Response of an Anatomically Accurate Finite Element Head Model
Authors: Rooks Tyler F. , Humm John , Baisden Jamie L. , Chancey Valeta Carol , Yoganandan Narayan
Published: January 2022

The need for an objective measure of injury in an area of the body that is difficult to study through experimental research methods combined with recent advancements in computational capabilities has led to a focus on development of detailed finite element models. Model development, anatomical detail, and injury metrics, however, varies widely. The purpose of this study was to benchmark the response of a newly developed anatomically accurate human brain model against the SIMon and GHBMC models and describe the predicted regional responses of the brain. The MCW-USAARL Head Injury Model (MUHIM) anatomy was developed using a neuroimaging atlas and neurosurgeon review. Material properties were obtained from literature. All three models were exercised using data from in-house laboratory tests that consisted of a helmeted head and neck mounted on a mini-sled device. Cumulative strain damage measure (CSDM) was calculated for each model using a strain threshold of 15, used in previous studies as a brain injury threshold. SIMon and GHBMC whole brain CSDM was 0.25 and 0.3 for the frontal and 0.40 and 0.3 for the lateral impact tests. Comparatively, whole brain CSDM from the MUHIM model was 0.27 for frontal tests and 0.45 for lateral tests. It is known that cognitive functions are region specific, and damage to one region may have specific neural sequela. Such regional or local metrics may explain different types of brain injuries.
Aligning Research Objectives With Student Learning Outcomes and Sustainability Objectives in Student Engineering Development Project
Authors: Al-Rawi Mohammad , Chand Praneel , Khanna Jai
Published: January 2022

To generate student projects that effectively inform tasks on a main project (MP), and enable students to participate in the development of a solution to a problem that affects user satisfaction with renewable energy solutions. This research contains a reflection on the mapping of project’s requirements to learning outcomes of the engineering development project (EDP) paper. Alignment to the goals and learning outcomes of the course will be discussed as well as broader implications for service learning and the potential for the project to be adapted to meet broader institutional objectives such as sustainability will be presented.

In conclusion, this paper describes the mapping of the graduate attributes and the learning outcomes in student projects to objectives of the MP, reflects on the achievement of these learning outcomes in the context of a project that fully explores all of them, and describes the service-learning potential for this type of student project.
Mathematical Modeling for Carbon Dioxide Level Within Confined Spaces
Authors: Yan Lincan , Yantek Dave S. , DeGennaro Cory R. , Fernando Rohan D.
Published: January 2022

Federal regulations require refuge alternatives (RAs) in underground coal mines to provide a life-sustaining environment for miners trapped underground when escape is impossible. A breathable air supply is among those requirements. For built-in-place (BIP) RAs, a borehole air supply (BAS) is commonly used to supply fresh air from the surface. It is assumed that the fresh air has an oxygen concentration of 20.9%. Federal regulations require that such a BAS must supply fresh air at 12.5 cfm or more per person to maintain the oxygen concentration between 18.5% to 23% and carbon dioxide level below the 1% limit specified. However, it is unclear whether 12.5 cfm is indeed needed to maintain this carbon dioxide level. The minimal fresh air flow (FAF) rate needed to maintain the 1% CO2 level will depend on multiple factors, including the number of people and the volume of the BIP RA. In the past, to predict the interior CO2 concentration in an occupied RA, 96-hour tests were performed using a physical human breathing simulator. However, given the infinite possibility of the combinations (number of people, size of the BIP RA), it would be impractical to fully investigate the range of parameters that can affect the CO2 concentration using physical tests.

In this paper, researchers at the National Institute for Occupational Safety and Health (NIOSH) developed a model that can predict how the %CO2 in an occupied confined space changes with time given the number of occupants and the fresh air flow (FAF) rate. The model was then compared to and validated with test data. The benchmarked model can be used to predict the %CO2 for any number of people and FAF rate without conducting a 96-hour test. The methodology used in this model can also be used to estimate other gas levels within a confined space.
Graphene Confined Polymer Thin Films Subjected to Supersonic Impact
Authors: Bowman Andrew , Roth Michael , Lawrimore William , Newman John
Published: January 2022

Due to their high specific penetration energy and high-strain-rate dependence, polymers are good candidates for lightweight protection against high-velocity impacts. Recent micro-impact experiments have shown enhanced abilities of polymer thin films to absorb remarkable amounts of energy during ballistic impacts. However, in situ observation of the molecular energy dissipation mechanisms is difficult or impossible, resulting in a gap in understanding. During confinement, the critically connected relationship between chain mobility, temperature, and pressure becomes more enigmatic as shock waves travel through the material. In this work, we use large-scale Molecular Dynamics (MD) simulations with reactive bond-breaking capabilities to gather insights into the nanoscale energy dissipation mechanisms of unconfined and confined polymers. Multi-layered graphene (MLG) sheets are used to create various MLG-polyethylene (PE) configurations, such as a PE with an MLG backing layer, and confined PE sandwiched between graphene. By varying the number and configurations of PE and MLG layers, the level of confinement on the PE can be increased. The resulting PE thin films, graphene films, and confined PE composites are subjected to a range of high-velocity impacts (500–7,500 m/s) to determine the amount of energy dissipation for the given material system. Unconfined PE experiences large void formation and chain pullout due to high entanglement density and low internal chain friction (small monomeric friction coefficient). With increasing levels of confinement, the energy dissipation mechanism transitions from chain disentanglement to chain scission, subsequently dissipating higher amounts of energy.
Analysis and Optimization of the Recoil-Compensated Absolute Gravimeter
Authors: Chen Yicong , Wu Kang , Wen Yi , Wang Lijun
Published: January 2022

The free-fall absolute gravimeter is commonly used for precise gravitational acceleration measurement. The g value is obtained through quadratic fitting of the position-time data pairs of the freely falling test mass. However, recoil vibrations are generated during the release of the test mass resulting from the movement of the center of mass of the chamber, and errors may arise from these vibrations in the measurement process. To solve the recoil vibration problem, previous researchers have developed the recoil compensation structure to achieve a basically stationary center of mass during the drop. In this paper, counterweights of a variety of masses are tested on our recoil compensated gravimeter, while recoil vibrations are recorded and analyzed accordingly. The multibody simulation indicates that compensated counterweights can significantly reduce the recoil vibration amplitude, making a more precise measurement attainable. In the experiments, accelerometers and seismometers are employed respectively in the simultaneous measurement of recoil vibrations of dropping chamber and reflector. Then all the vibration signals are analyzed and compared, and the outcome confirms the effectiveness of the gravimeter in performing high precision measurement as what is observed in the previous simulations. With a proper design of the counterweight mass, the recoil effect can be significantly reduced during the test procedure, which indicates a potential for high precision measurement.
A Meso-Scale Fretting Fatigue Simulation Method Based on Submodelling Technique
Authors: Wang Jian , Zhou Caizhi
Published: January 2022

This work developed a macro-microscopic coupled simulation method for fretting fatigue simulations. The crystal plasticity finite element (CPFE) mode was used to predict the hotspot of crack nucleation in fretting fatigue loading. Our model has considered the microstructure features of metals, such as the grain size, grain orientations and dislocation slips, in the fretting fatigue simulations, most of which have been ignored in previous work. And the submodel approach has been adopted in our work to overcome the size limitation and minimize the effect of boundary constrains. After calibration of material parameters, the model has been validated by the Hertz’s analytic solution based on the contact mechanics. From the results of CPFE simulations, we can accurately identify the hotspot of crack nucleation in fretting fatigue loading based on the local the equivalent plastic strain. The global model-submodel coupling method proposed in this work provides a solution for prediction of crack initiation and the crack initiation life of fretting fatigue in metals.
Learning While Playing or Playing While Learning?
Authors: Soares Filomena , Alves Anabela C.
Published: January 2022

This paper presents how two teachers of different courses of the third year of the Integrated Master of Industrial Engineering and Management from the University of Minho engaged students in a learning experience. By doing this, teachers considered that it is easier for the students to learn the course contents. The goal of this experience was to challenge students to acquire competencies in Process Control and Automation and Production Systems Organization I courses, in a friendly and cooperative way. Attending that students are digitally natives, curious, and easily think “out of the box”, the question is to shoot the trigger and motivate them. Achieving this, they respond with a dedicated and professional attitude, applying the acquired competencies to develop creative products and production systems. Some results of this learning experience are presented in the paper and include the concepts and outputs they produced. The student’s qualitative feedback was very positive and enthusiastic which allowed the authors to conclude that this type of challenge is worth investing in future editions of the courses. A limitation of this learning experience is the high number of students in each team.
Molecular Dynamics Simulation of Thermal Conductivity of Uranium Mononitride
Authors: Moussa Hassane Ayouba , Qingyu Wang , Ado Mohammed , Enivweru Doctor
Published: January 2022

The underline challenge of low thermal conductivity which is responsible for high centerline temperature in Uranium-dioxide (UO2) nuclear plant fuel type associated with the current generation of commercial reactors remains a huge concern to the nuclear power industry. Although, researchers in the nuclear industry have proposed uranium mononitride (UN) as a promising candidate for accident tolerant fuel and Generation-IV nuclear reactor fuels, unfortunately, there is still a lack of clear understanding of the point defects influence on the thermal conductivity of UN. This paper applies the reverse-NEMD method to study the effect of point defects on phonon thermal conductivity in UN perfect crystal. Experimental and simulation relevant literatures were reviewed to analyze the influence of defects on the phonon thermal conductivity of UN. The thermal conductivity of uranium mononitride increases quickly with the temperature and the phonon contribution decreases with an increase in vacancies concentration. Uranium vacancy has a detrimental effect on the phonon thermal conductivity of UN at lower vacancy concentration. Results from this research would help with the understanding and application of UN in nuclear engineering.
Mobile Solar Powered Instructional Technology Equipment for Online Teaching and Learning During COVID-19 Pandemic for Remote Community
Authors: Galindo Ronald M. , Obiso Jun-Jun A.
Published: January 2022

As the COVID-19 pandemic continues globally, the disruption of the traditional face-to-face classes in educational institutions is evident. In the Philippines, these educational institutions have shifted to Flexible Learning System (FLS). However, in the implementation of FLS, the teachers and the learners in the remote communities experience internet connectivity problems. This problem is minimized using mobile solar-powered instructional technology equipment for online teaching and learning activities. This equipment is designed to carry all the necessary accessories in the online delivery of FLS like television, solar panel, WiFi routers, inverters, and other power accessories. It is made of Polypropylene Random Copolymer (PPR) pipe material and is mounted on a four-wheel bicycle. Several tests were conducted to evaluate the performance of the equipment. These were the following: stress analysis, solar energy utilization test, portability assessment, connectivity speed test, and quality assessment. Results suggest that the developed equipment is ready for actual deployment in a remote community in the Philippines. With such deployment, internet connectivity problems can be minimized. As a result, the less fortunate learners can have free and reliable internet access. Moreover, a possible related future work is designing bigger mounting equipment that can carry more accessories due to its portability and mobility aspects.
Drone Assisted Targeting for Direct Fire Engagements
Authors: Batta Nathan , Williams Grant , Murphy Shane , Quantz Andrew , Pegues John , Manjunath Pratheek , Bluman James
Published: January 2022

The goal of the project is to develop a drone and recovery station system capable of tracking a target and round fired from a tank. Key aspects of the project include maintaining a level platform through the shot, performing accurate localization, and reacting to movements in the tank turret. The goal is for the design to be able to operate in GPS-denied and light-denied environments. After significant testing and research, the drone will be placed 10 meters behind and 20 meters above the tank muzzle and the recovery station will be placed on the rear of the tank. The drone will perform localization using visual-inertial odometry (VIO) and will react to movements in the tank turret by using a filtered IMU to send up the tank’s azimuth. All communication will be transmitted over WiFi and the video from the camera will be livestreamed on the recovery station laptop. In this semester, key areas of focus will be validating the VIO algorithm, developing a method for aligning the drone with the tank turret, establishing communication over WiFi, and then conducting final testing.
Ultimate Lightweight Design Based on Shakedown Strength and Its Application on Designing a Manned Airtight Module
Authors: Huang Songhua , Xu Yugong , Zhang Lele , Chen Geng , Zeng Fuming , Liu Feng
Published: January 2022

Structural lightweight optimization design is classically performed according to the elastic limit rule, which leads to an unacceptable structure weight or strength redundant to an extent. Shakedown theory is implemented in the present study to assess the load-bearing capacity of the structure. Within the shakedown load limit, failure forms of ratcheting, incremental collapse and alternate plasticity will be avoided. Moreover, the full potential of a material can be utilized by following the shakedown limit framework. Therefore, under this framework, by sacrificing some abundant loading bearing capacity, an extremely lightweight design of the structure can be reached. The current research presents a mathematical and algorithmic framework for producing extreme lightweight designs of structures that exhibit constrained shakedown loading capacity, which is an innovative means to the lightweight design and makes the optimal structure design in a relatively practical way. The hybrid genetic algorithm is introduced to obtain a more accurate global solution. The accuracy and effectiveness of the proposed numerical optimization method are validated and demonstrated by a classical problem and subsequently adopted in optimal parameter design of the connecting structure to be used in a manned airtight module. In the end, the research suggests an optimal result for both load capacity and lightweight design for the manned airtight module. And an ultimate lightweight design is given by sacrificing redundant load capacity. This study confirmed that the hybrid genetic algorithm is an effective means for determining the optimal parameter in accordance with the shakedown constraints. In addition, the results of this study support the idea that shakedown analysis should be used in the optimization design of airtight modules instead of using the traditional elastic limit rule. As the load capacity evaluates by shakedown analysis would be more factual. Moreover, this study highlights the design performance enhancements attributed to allowing redundant shakedown load capacity to exchange an ultimate reduction of material.
Autonomous PV Panel Inspection With Geotagging Capabilities Using Drone
Authors: Rezk Mahmoud , Aljasmi Nawal , Salim Rufaidah , Ismail Hesham , Nikolakakos Iraklis
Published: January 2022

According to the International Renewable Energy Agency (IRENA), photovoltaic (PV) production anticipates an increase of 10% in 2021. The rapid increase in the PV panels installation requires a robust inspection method of existing solar parks to maintain efficiency and productivity levels. With advancements in drone technology, Unmanned Aerial Vehicles (UAV) are being used to inspect the solar parks, either flown manually or autonomously. Furthermore, there are various image processing approaches to analyze the data gathered. However, current practical application techniques do not effectively localize the defective panels present within the solar farm. This paper proposes a method to inspect large-scale solar parks using an autonomous drone equipped with Real-Time Kinematic (RTK) and camera. The proposed method is a fully autonomous solution for inspecting PV panels, with effective detection and localization of faults. It can ease the procedure of inspection by automating it and give highly reliable results.
Injection Molded Metal-Plastic Hybrids Based on Femtosecond Laser Structuring
Authors: Yang Can , Peng Fei , Yin Xiao-Hong , He Tiefeng , Zheng Xiuhong
Published: January 2022

In the present work, femtosecond-pulsed laser was used to induce hierarchical hole-shaped surface micro-structures for producing metal-plastic hybrid (MPH) components using injection molding. By changing laser variables such as the scanning speed, laser power and scan repetition, hole-shaped micro-structures with different depths were obtained. From the scanning electron microscope (SEM) observations, one could find that the bottom of hole-shaped micro-structures are covered with micro-scale spherical protrusions showing cauliflower-like structures under certain processing conditions. At the same time, laser induced periodical surface structures (LIPSS) appears on the bottom and inner wall of the hole-shaped micro-structure. In addition, internal profiles of the hole-shaped microstructures were characterized using the laser confocal microscope (LCM). It’s found that laser processing parameters such as the laser scanning speed and the scan repetition show a linear relationship with the depth of the hole-shaped structure. Specifically, the micro-structure depth increases with the increase in the laser power and scan repetition, but decreases with the increase in the scanning speed. The tensile test of the injection-molded MPH joints showed that deeper hole-shaped micro-structures make significant contribution to the bonding strength of the joint. Meanwhile, the presence of multi-scale micro-structures also has positive effect on the MPH bonding strength.
Fluence As an Instrument Towards a Unified Representation of Fluiddynamic Related Phenomena
Authors: Michele Trancossi , Pascoa Jose
Published: January 2022

According to the intuition by Maurice Antony Biot, the concept of Fluence can easily describe different and interdisciplinary physical phenomena. Fluence relates directly to the number of particles that cross or hit a reference surface, directly impacting the specific problem. Moreover, when related to the time, it allows describing the flux of particles through the reference area. Therefore, the physical properties which are transported by the particles can be easily associated with specific problems with an unprecedented easiness of use.

Laser beams, particles, ions beams, acoustic and fluid dynamic problems can benefit from this concept for specific and standard description. Moreover, even if referred only to the number of particles, it avoids using complex statistical methods such as the kinetic theory of the gasses.

This paper is an homage to the work of Maurice Antony Biot and shows how the Fluence concept can be helpful in the solution of multiple physical problems.
Optimization of Riveting Assembly Process Parameters for Aviation Large Panels Based on Mesoscopic Features
Authors: Kang Yonggang , Ren Haodi
Published: January 2022

The aviation large panel is an important component that constitutes the aerodynamic shape of the aircraft. It has the characteristics of large size, thin wall and weak rigidity. It is prone to produce assembly deformation during the automatic drilling and riveting assembly connection process, including the overall bending and torsion deformation of the panel, and the defects around the rivet. In this paper, through the test of automatic drilling and riveting assembly of large panels, a local sinking deformation along the axis of the long stringer is found. The cause of this deformation problem is complex and directly affects the subsequent assembly process. It is a strong coupling problem between the automatic drilling and riveting process and the elastic-plastic deformation of the rivet and its connected parts, and it has a high correlation with the meso-structure of the plate structure around the nail hole after the rivet is riveted.

Aiming at this deformation problem, this paper first established a process model of the riveting process and designed riveting test pieces with different process parameters. The effects of riveting force, riveting process time, and upper riveting cavity on the meso-structure of the riveting area are explored, and the correlation between the meso-structure of the riveting area and the riveting process parameters is analyzed. Then, based on the above research, a finite element numerical model of a typical aircraft siding riveting component structure including meso-structure is established. Through the finite element simulation calculation of the model, the coupling relationship between macroscopic deformation and mesoscopic structure is further explored, the existence of local subsidence and deformation along the axis of the long truss is verified.
Slip Suppression Control to Improve the Performance of a Mobile Cleaning Robot Under Different Road Surface Conditions
Authors: Yamatogawa Tsubasa , Morimoto Tatsuhiro , Tsuno Takaya , Shen Tian , Yano Ken’ichi , Arima Toshihiko , Fukui Shigeru
Published: January 2022

When iron ore and coal cargo are unloaded onto a ship, some of that cargo falls, and can eventually pollute the sea. As a countermeasure, workers clean the cargo hold doors, but this dangerous activity has caused fatal accidents due to falls. The use of robots in cleaning work has a problem. That is the occurrence of slippage when a compact and lightweight robot attempts to clear a heavy obstacle. In this research, we aim to suppress slippage by controlling the driving force of the cleaning robot according to changes in the suiface conditions. We proposed a slip suppression control system that achieves slip suppression by controlling the driving force according to the estimated variation of the friction coefficient. In order to verify the effectiveness of the proposed method, we produced a test course with essential features of a work site, and then we carried out a heavy load transport test of the cleaning robot. We demonstrated an effective slip suppression system for the lightweight robot that can respond to variable friction on a suiface that changes as it is cleaned.
Evaluation of Virtual Reality Interface Interaction Methods for Digital Twin Industrial Robot Programming and Control, A Pilot Study
Authors: Pizzagalli Simone , Kuts Vladimir , Bondarenko Yevhen , Otto Tauno
Published: January 2022

Extended Reality (XR) interfaces for Human-Robot Interaction (HRI) allow for safe and flexible control and programming of advanced industrial systems and integrate the operator as part of the Digital Twins (DT) interfaces of real collaborative systems. These technologies already show their potential in real-life scenarios by providing valuable training, quality control, maintenance, remote control and assistance tools. XR could also favor the development of new metrics and methods in human-robot collaboration (HRC) by providing safe and reproducible testbeds for the standardization of HRI in collaborative scenarios. This can be achieved by attaining a reliability level that would avoid the degradation of user experience in HRI. XR DT systems and interfaces need to be assessed on their impact on the operator, but also in terms of interaction efficacy and efficiency within the virtual scenario. This evaluation should be performed on both virtual reality (VR) visualization and interaction hardware and virtual user interfaces (VUI) in immersive scenarios. There is a lack of evaluation of performance and usability of VUI input methods. Our work aims at assessing three types of input paradigms with a VUI controlling a DT robot arm in a simple pick and place task and which can be based on different VR controller devices. Objective metrics are collected during the task while NASA TLX, SUS and UEQ are used to assess user workload, usability of the system and user experience for each interaction method.