bluuebunny/crossref_metadata_2025 huggingface dataset:
Remaining Useful Life (RUL) Prediction of Rolling Element Bearing Using Random Forest and Gradient Boosting Technique
Authors: Patil Sangram , Patil Aum , Handikherkar Vishwadeep , Desai Sumit , Phalle Vikas M. , Kazi Faruk S.
Published: January 2019

Rolling element bearings are very important and highly utilized in many industries. Their catastrophic failure due to fluctuating working conditions leads to unscheduled breakdown and increases accidental economical losses. Thus these issues have triggered a need for reliable and automatic prognostics methodology which will prevent a potentially expensive maintenance program. Accordingly, Remaining Useful Life (RUL) prediction based on artificial intelligence is an attractive methodology for several researchers. In this study, data-driven condition monitoring approach is implemented for predicting RUL of bearing under a certain load and speed. The approach demonstrates the use of ensemble regression techniques like Random Forest and Gradient Boosting for prediction of RUL with time-domain features which are extracted from given vibration signals. The extracted features are ranked using Decision Tree (DT) based ranking technique and training and testing feature vectors are produced and fed as an input to ensemble technique. Hyper-parameters are tuned for these models by using exhaustive parameter search and performance of these models is further verified by plotting respective learning curves. For the present work FEMTO bearing data-set provided by IEEE PHM Data Challenge 2012 is used. Weibull Hazard Rate Function for each bearing from learning data set is used to find target values i.e. projected RUL of the bearings. Results of proposed models are compared with well-established data-driven approaches from literature and are found to be better than all the models applied on this data-set, thereby demonstrating the reliability of the proposed model.
Effect of Calcium Hydroxide and Water to Solid Ratio on Compressive Strength of Mordenite-Based Geopolymer and the Evaluation of its Thermal Transmission Property
Authors: Cornejo Mauricio H. , Elsen Jan , Togra Bolivar , Baykara Haci , Soriano Guillermo , Paredes Cecilia
Published: January 2019

Mordenite-rich tuff is one of most available zeolitic rocks all over the world. Because of this, the research of natural mordenite as a raw material of geopolymeric materials can provide an almost unlimited source of solid precursor for manufacturing such building materials. Despite efforts to shed light on the behaviour of mordenite-rich tuff during geopolymeric reaction, the performance of these novel materials is barely understood. The aim of this study is to explore the effect of the content of calcium hydroxide, CH, and water-to-solid ratio, W/S, as mixing parameters on compressive strength of mordenite-based geopolymers, MBG, and its thermal conductivity.

As solid precursor was used mordenite-rich tuff and mixed with sodium hydroxide (NaOH) at 10M that kept constant during the experiment. Two experimental parameters were selected as independent variables i.e, the content of CH and water-to-solid ratio, and their levels, according to a central composite experimental design. All these designed mixes were characterized by using quantitative X-ray diffraction (QXRD), Fourier Transform Infrared spectroscopy (FTIR), Thermogravimetry and differential scanning calorimetry (TGA-DSC), scanning electron microscopy coupled with energy dispersed spectroscopy (SEM-EDS), in addition thermal conductivity tests were also run according to standard method ASTM C177 at 9, 24, 39°C. The overall results suggested that MBG can be used as building material, however its thermal conductivity was higher than that of commercial isolate building material. The experimental design analysis indicated that the optimum water-to-solid ratio was 0.35, but in the case of the content of CH, the optimum value was not observed on this experimental range because the compressive strength increased as the content of CH increased as well. The compressive strength of MBG was observed in the range between 8.7 and 11.3 MPa. On the other hand, QXRD and FTIR showed that mordenite reacted during the geopolymeric reaction, but instead quartz, also found in zeolitic tuff, acted as inert filler.
Assessing the Educational Effectiveness of a System Engineering Software in Capstone Design Projects
Authors: Xiao Angran , Gailani Gaffar , Zhang Shaojin
Published: January 2019

The increasing complexity of engineering and technology requires that students master an increasing amount of abstract knowledge to remain competitive in today’s job market. However, today’s students find it difficult to create mental images of abstract concepts, due to lack of real world experience. This problem is more evident in advanced design classes teaching product design concepts and methodologies. In this paper, we introduce a system engineering software package that is used in our capstone design class, with which students are able to create their own framework of product development activities, control information flows, and manage tools and engineering models in each activity. This allows them to plan out and manage their projects using the design methodologies that they learned in class. We assessed student learning in the capstone design class for the last 7 semesters. Independent Samples t-Test and factorial ANOVA are used to analyze the student performance before and after using the software package. We have observed that in the design classes, the system engineering software enables students to practice design methodologies by visualizing and managing product development processes. This helps students not only understand the abstract design methodologies, but also apply the methodologies to their projects and accomplish them more efficiently.
Shear Stress Induced Calcium Dependent Nuclear Deformation in Epithelial Cells
Authors: Jetta Deekshitha , Verma Deepika , Maneshi Mohammad M. , Hua Susan Z.
Published: January 2019

External mechanical forces can reach the cell nucleus causing changes in nuclear morphology, size and motility. A common explanation is that these forces are transmitted by surrounding cytoskeleton network through its linkage to nuclear envelope; shear stress causes reorganization of cytoskeleton, thus, the changes in nuclear shape. In this study, we measured nuclear shape and intracellular Ca2+ under fluid shear stress in MDCK cells using a parallel plate microfluidic chip. We show that fluid shear stress (1.1 dyn/cm2, 3 hrs) causes significant changes in nuclear shape in cells, from a flat disk shape having larger area to a thicker disk having smaller area. An increase in intracellular Ca2+ is required for shear induced nucleus deformation. Inhibiting Ca2+ influx with GsMTx4 and Gd3+ eliminated Ca2+ influx and abolished the nuclear deformation. The cytoskeleton reorganization occurred in parallel with Ca2+ rise in the cells. Increasing intracellular Ca2+ with thapsigargin that depletes the Ca2+ stores resumed the nuclear deformation. This suggests that shear induced nuclear deformation is a Ca2+ dependent process.
Experimental Study of Chamber Volume Effect on Bubble Formation From Orifice Plates Submerged in Water
Authors: Gokhale Omkar S. , Jog Milind A. , Manglik Raj M.
Published: January 2019

Experimental study of air bubble formation from orifice plates submerged in water pools has been carried out. Air is forced through the orifice by supplying it to a chamber connected to the orifice plate. The chamber volume plays an important role in determining the bubble growth time as well as bubble size and shape at departure. The effect of chamber volume is generally correlated in term of a dimensionless parameter, capacitance number (Nc), which is proportional to the chamber volume and is inversely proportional to the square of the orifice diameter. To better understand and characterize this effect, an experimental study is performed using ten orifice plates of diameter ranging from 0.61 mm to 2.261 mm with six different chamber volumes between 12 cc and 59 cc with the corresponding capacitance numbers varying from 0.2 to 19. The shape and size of the bubble are captured using high speed videography. The orifice plate material is acrylic glass which has an equilibrium contact angle of 38° with pure water. It was observed that the value of critical capacitance number or Nc above which the bubble evolution is affected by the gas chamber volume, is around 0.85. The bubbles are more spherical in shape, and the growth time is significantly smaller. Also, at high capacitance number (Nc > 7), the air flow in the bubble is so high that the bubble departs with a sharp apex and has a large volume. Above Nc > 10, the chamber effects plateau and further increase in gas chamber volume does not alter bubble size and shape at departure.
Retrofitting Gas Turbine Units Parabolic Trough Concentrated Solar Power for Sustainable Electricity Generation
Authors: Alnahdi Wael , Al Shamsi Sara , Alantali Wafaa , Al Shehhi Shaikha , Hassan Ali Mohamed I.
Published: January 2019

Shamsl is hybrid solar/natural-gas concentrated solar power (CSP) plants. The plant is also integrated with a booster gas-fired-heaters for steam superheating. In addition to direct fire-heaters to the heat transfer fluid (HTF) for supplying thermal energy during the night or whenever the solar irradiance level is dimmed. However, there is a more sustainable way to avoid power-generation-outages caused by transient weather conditions without a significant plant reconstruction, i.e. integration with gas turbines. In this study, a thermodynamic model of Shamsl integration with gas turbines is developed to investigate the gas turbine capacity and the exergitic efficiency of the supplied gas with and without the gas turbine involvement. The HTF heaters will receive the needed thermal energy from the gas turbines exhaust gases instead of the direct fire-heater (case1). Another potential is replacing the booster fire heaters with the gas turbine system as well. (case2). A parametric study is conducted to determine the size and the requirements of a gas turbine system for the specified power target demand in addition to a feasibility study for the proposed system. The results showed that using two gas turbines for the HTF heater significantly improved the overall efficiency and reduces the CO2 emission. Replacing the booster heater with two gas turbines improves the efficiency up to excess air factor of 2.5.
Side Structure Integrity Research for Passenger Rail Equipment
Authors: Eshraghi Shaun , Carolan Michael , Perlman A. Benjamin
Published: January 2019

The U.S. Department of Transportation (DOT) Federal Railroad Administration (FRA) began promulgating regulations for the structural crashworthiness of passenger rail equipment at 49 Code of Federal Regulations (CFR) Part 238 on May 12, 1999. These Passenger Equipment Safety Standards (PESS) [1] include requirements affecting the designs of sidewall structures on passenger rail equipment. The FRA’s Office of Research, Development and Technology and the DOT’s Volpe National Transportation Systems Center are conducting research to evaluate the side impact strength of Tier I passenger rail equipment designs that have been constructed according to the current side structure regulations in §238.215 and §238.217.

Following a fatal 2011 accident in which a highway semitrailer truck impacted the side of a passenger train that was transiting a grade crossing in Miriam, NV, the National Transportation Safety Board (NTSB) recommended that the FRA “develop side impact crashworthiness standards (including performance validation) for passenger railcars that provide a measurable improvement compared to the current regulation for minimizing encroachment to and loss of railcar occupant survival space” [2].

This paper describes the status of the current FRA research related to side structure integrity and describes the planned next stage of the research program which will include analyzing the performance of generalized passenger railcar structures in side impact collision scenarios. A discussion of the technical challenges associated with analyzing side impacts on passenger rail equipment is also presented.
Investigation and Modeling of Flag Generation in Honeycomb Sandwich Panel Machining
Authors: Yip-Hoi Derek M. , Gill David D.
Published: January 2019

Light weight honeycomb structures lend themselves to important applications in aerospace. These range from aerodynamic and structural components such as wing edges, flaps, rotor blades and engine cowlings, to aircraft interior structures such as overhead luggage bins, compartment liners, bulkheads and the monument structures found in galleys and lavatory areas. Often the honeycomb is formed into a composite ply sandwich with fiberglass face sheets bonded to the honeycomb core. These panels are cut to shape using CNC routers and specially designed cutting tools. However, the quality of the cuts generated even with these special tools leaves much to be desired. The low stiffness of the structure leads to imperfections such as fraying of the cut face sheet edges and the generation of flags along the cut honeycomb edge. These impact the ease of assembly and often require manually intensive reworking to mitigate.

The cutting of honeycomb structures and sandwich panels is challenging due to low stiffness, anisotropic mechanical properties and a high proportion of interrupted cutting due to the air voids that are present. The cutting mechanics are not well understood at this time.

This paper presents findings from the study of cutting of honeycomb sandwich panels using high speed videography and correlates these with results of geometric modeling of the engagement between the cutter and workpiece. The study includes the impact of the trajectory of the tool path through the cell structures on the generation of flagging. It also reports on the effects of two different cutting tool geometries and the introduction of a lead angle on the size and structure of the flags generated. These findings present the case for a research regime similar to the one completed for solid metals, into modeling the mechanics behind machining honeycomb structures. This will help manufacturers using these materials to make better choices in the tools, cutting parameters and machining strategies that they employ in their process planning.
A Game-Theoretic Approach to Defending Nuclear Instrumentation and Control Systems From Cyber-Threats
Authors: Maccarone Lee T. , Cole Daniel G.
Published: January 2019

Cyber-physical systems consist of interconnected physical processes and computational resources. Because the cyber and physical worlds are integrated, the system’s physical assets are vulnerable to cyber-attack. An attacker who is able to access control inputs and mask measurements can damage the system while remaining undetected. By masking certain measurement signals, an attacker may render part of the state space unobservable, meaning that it is impossible to reconstruct those states. This is called an observability attack.

A game-theoretic approach is presented to analyze observability attacks. The attacker’s strategy set includes all possible combinations of masked measurements. The defender’s strategy set includes redundant sensing and direct measurement of state variables. Attacker and defender payoffs are quantified using the responses of the observable and unobservable states. The observability attack game is analyzed for a nuclear balance of plant system. Combinations of sensor omissions are analyzed to find observability attacks with high impact and low detection. The effects of sensor augmentation are examined. A pure strategy Nash equilibrium is identified.
Analysis of the Fluid Motion Induced by a Vibrating Lamina Through Free Surface-Lattice Boltzmann Coupled Method
Authors: Chiappini Daniele , Di Ilio Giovanni , Bella Gino
Published: January 2019

In this work, we perform a numerical study on the flow induced by the motion of a rigid cantilever beam undergoing finite amplitude oscillations, in a viscous fluid, under a free surface. To this aim, we use a lattice Boltzmann volume of fluid (LB-VOF) integrated method, which includes the tracking of the fluid surface. The adopted approach couples the simplicity of the LB method with the possibility to track the free surface by means of a VOF strategy. Through a parametric analysis, we study the effects related to the depth of submergence, for several values of the oscillation frequency and amplitude. Results are provided in terms of a complex hydrodynamic function, whose real and imaginary parts are the added mass and the viscous damping, respectively, acting on the lamina. Validation of the results is carried out by comparing the solution, for the limit case of lamina submerged in an infinite fluid, with those from available literature studies. We find that the presence of the free surface strongly influences the flow physics around the lamina, especially at low values of the depth of submergence. In facts, when the lamina approaches to the free surface, the fluid waves, generated by the motion of the lamina, interact with the oscillating body itself, giving rise to additional effects, which we quantify in terms of added mass and viscous damping.
Mitigation of Greenhouse Gas Emissions Through the Shift From Fossil Fuels to Electricity in the Mass Transport System in Guayaquil, Ecuador
Authors: Ramirez Angel D. , Arcentales Danilo , Boero Andrea
Published: January 2019

Climate change is a serious threat to sustainability. Anthropogenic climate change is due to the accumulation of greenhouse gases (GHG) in the atmosphere beyond natural levels. Anthropogenic GHG emissions are mostly associated with carbon-dioxide (CO2) originated in the combustion of fossil fuels used for heat, power, and transportation. Globally, transportation contributes to 14% of the global GHG emissions.

The transport sector is one of the main contributors to the greenhouse gas emissions of Ecuador. In Guayaquil, the road mass transportation system comprises regular buses and the bus rapid transit (BRT) system. Electricity in Ecuador is mostly derived from hydropower, hence incurs relatively low GHG emissions along its life cycle. Therefore, electrification of transport has been seen as an opportunity for mitigation of GHG emissions.

In this study, the effect of partial replacement of the bus rapid system fleet is investigated. Feeders have been chosen as the replacement target in five different scenarios. GHG emissions from diesel-based feeders have been calculated using the GREET Fleet Footprint Calculator tool. The GHG emissions associated with the electricity used for transportation is calculated using the life cycle inventory of the electricity generation system of Ecuador. Three energy mix scenarios are used for this purpose. The 2012 mix which had 61% hydropower; the mix of 85% hydropower and the marginal electricity scenario, which supposed the extreme case when the new demand for electricity occurs during peak demand periods.

Results indicate that mitigation of GHG emissions is possible for almost all scenarios of percentage fleet replacement and all mix scenarios. Electric buses efficiency and the carbon intensity of the electricity mix are critical for GHG mitigation.
Hypo/Hyperglycemic Constrained Design of IV Insulin Control for Type 1 Diabetic Patients With Meal and Initial Condition Uncertainties Using Sequential Quadratic Programming
Authors: Nandi Souransu , Singh Tarunraj
Published: January 2019

The focus of this paper is on the development of an open loop controller for type 1 diabetic patients which is robust to meal and initial condition uncertainties in the presence of hypo- and hyperglycemic constraints. Bernstein polynomials are used to parametrize the evolving uncertain blood-glucose. The unique bounding properties of these polynomials are then used to enforce the desired glycemic constraints. A convex optimization problem is posed in the perturbation space of the model and is solved repeatedly to sequentially converge on a sub-optimal solution. The proposed approach is demonstrated on the classic Bergman model for Type 1 diabetic patients.
Adiabatic Analysis of Rotary Displacer Stirling Engine
Authors: Bagheri AmirHossein , Mullins William C. , Foster Phillip R. , Bostanci Huseyin
Published: January 2019

Utilizing analytical models at the initial stages of Stirling engine (SE) development is a common approach since the cost could be excessive when experimental (i.e., building prototypes) or even numerical (i.e., using Computational Fluid Dynamics (CFD)) approaches are taken first. One of the well-known analyses in this area is the adiabatic analysis that assumes working fluid to be an ideal gas, and adiabatic expansion and compression processes in the power cylinder. Although adiabatic analysis neglects pressure loss in the cycle, it still predicts operating envelope and performance with a better accuracy compared to isothermal (Schmidt) analysis. This study considers the adiabatic analysis that was originally developed for conventional, reciprocating displacer SE configuration, and aims to adapt it for an innovative, rotary displacer SE configuration. The analysis enables to present pressure-volume diagrams, and estimates the amount of generated work and the efficiency. The results, when compared to that of the ideal Schmidt analysis, indicate up to 4.6% lower values of the generated work, suggesting a significant difference between the two ideal assumptions.
Chance Constraint Based Design of IV Insulin Control for Type 1 Diabetic Patients Under Model and Meal Uncertainties
Authors: Nandi Souransu , Singh Tarunraj
Published: January 2019

The focus of this paper is on the development of a chance constrained controller for type 1 diabetic patients in the presence of model, meal and initial condition uncertainty. Since the chance constraints require the mean and variance of the evolving uncertain blood-glucose, a conjugate unscented transform based approach is used to estimate the blood-glucose statistics. The proposed approach is demonstrated on the classic Bergman model augmented with a gut dynamics model.
Strain Effect on Thermal Transport in Carbon Nanotube-Graphene Junctions
Authors: Park Jungkyu , Pena Paul
Published: January 2019

We employ molecular dynamics simulations to explore the effect of tensile strain on the thermal conductivity of carbon nanotube (CNT)-graphene junction structures. Two different types of CNT-graphene junctions are simulated; a perfect seamless junction between CNT and graphene with complete sp2 covalent bonds, and a CNT-graphene junction with mixed sp2/sp3 covalent bonds are studied. The most interesting phenomenon observed in the present research study is that the thermal conductivity of CNT-graphene junction structures increases with an increase in mechanical strain. For the case of CNT-graphene junction structure with pillar height of 50 nm and inter-pillar distance of 15 nm, the thermal conductivity is improved by 22.4% when 0.1 tensile strain is imposed. It is observed that the thermal conductivity improvement is enhanced when a larger graphene floor is placed between junctions since larger graphene floor allows larger deformation (larger tensile strain) in the junction. In addition, the thermal conductivity of CNT-graphene junction structures with pure sp2 bonds is observed to be higher than the thermal conductivity of CNT-graphene junction structures with mixed sp2/sp3 bonds regardless of the amount of tensile strain. The obtained results will contribute to the development of flexible electronics by providing a theoretical background on the thermal transport of three dimensional carbon nanostructures under deformation.
Resolving the Electrochemical Equations of a Solid Oxide Fuel Cell for Use in Transient Simulation and Integration Into Cyber-Physical Systems
Authors: Arias Jesus E. , Haynes Comas L. , Giorges Aklilu G.
Published: January 2019

A major challenge with complex cyber-physical systems stems from long model computational time that creates a mismatch between the model system and the physical system. The numerical modeling of solid oxide fuel cells (SOFCs) presents particular challenges due to the highly coupled nature of the underlying equations and the multiphysics needed to fully resolve their behavior during a transient event. To this end current approaches revolve around splitting the computational efforts into resolving temperature effects and resolving electrochemical effects. Current methods employed for the transient simulation of an SOFC for implementation in the Hybrid Performance (HyPer) facility cyberphysical plant at the National Energy Technology Laboratory reveal a distinct need for accelerated results with a high degree of stability. To this aim, an investigation into the computational time for the code reveals that the underlying electrochemical algorithm takes an order of magnitude more time than its thermal counterpart and has a tendency to vary in terms of iteration time and as such a rework of the underlying system is proposed.

The primary method for accelerated electrochemical algorithm solutions is to employ higher order root finding recipes for the resolution of the highly coupled electrochemical equations. This is done with the intention to reduce the overall number of subiterations necessary for resolving voltage, current density, and species concentration, properties of the fuel cell that are all directly coupled and require nested iterative approaches. The overall objective of this approach is an order of magnitude reduction in calculation time without sacrificing stability and increasing accuracy. Specific approaches involve using both bounded and unbounded techniques, such as the False Position method and the Secant method (or if applicable Newton-Raphson) respectively, the drawbacks being slower convergence for False Position and instability for the Secant or Newton-Raphson methods.

Current preliminary results on simplified versions of the parent functions involved for electrochemical calculations indicate a reduction in computational steps by a factor of two for the secant method and a factor of three for Newton-Raphson. When implemented into new modified electrochemical algorithms, the results indicate a possible order of magnitude reduction in calculation time.
Assessment of Three Dimensional CAD Models Using CAD Application Programming Interface
Authors: Joo Sung-Hwan
Published: January 2019

It has been always a challenge to grade and assess the students’ CAD (Computer-Aided Design) three-dimensional models in the class. The high number of the files and complexity of models make the task time-consuming and tedious many times. For example, even opening and closing each CAD file takes a lot of time. When hundreds of CAD models need to open and verified, it takes more than one hour to finish the task. The work has been done to simplify this task and make it easy using Commercial CAD software’s API (Application Programming Interface), which can be used to automate and customize the CAD software. The API contains hundreds of functions that you can call from Visual Basic for Applications (VBA), VB.NET, Visual C#, Visual C++ 6.0, and Visual C++/CLI. These functions provide direct access to CAD functionality such as opening a file, check the important physical properties of three-dimensional models. Custom API program has been programmed for the task. The custom program executes the internal commends in CAD software and retrieve the data you need from each CAD file automatically. The program opens the multiple CAD files in the folder and check each file’s physical properties and save the information in MS Excel for the review. The program checks the volume (w.r.t the given coordinates) in two standard units (English and S.I. Units), the creator of model (to prevent the plagiarism) and degrees of sketch. In this paper, the following topics will be discussed and presented. 1) The problem with manual grading and assessment, 2) History and background of API functionality in commercial CAD software, 3) Examples of simple source code for API usage, 4) Running example of the API program for the given task, 5) Comparison between manual assessment and automatic assessment using API in terms of spent time. 6) Future improvement with API program. Actual demonstration of the program will be given during the presentation.
Fatigue Life Prediction of Cold Rolled Rotary Shouldered Threaded Connections
Authors: Song Fei , Du Michael , Li Ke
Published: January 2019

The bottom hole assembly (BHA) of a modern drill string for directional drilling mainly comprises a drill bit, a rotary steerable system, and a measurement while drilling tool. The tools and subs used on a BHA are screwed together through rotary shouldered threaded connections. Each connection is made up with a pin and a box. These connections are the weakest links when the BHA undergoes a large number of revolutions in a curved well section. When the fatigue life of a connection is consumed during a drilling job, a twist-off would occur, which could result in an enormous amount of non-productive time and possibly loss of the bottom BHA section in the hole. Cold rolling has proven to be able to improve fatigue resistance of a threaded connection by pressing a rolling wheel against the thread root and generating a layer of compressive residual stress at the root. Understanding how cold rolling improves fatigue resistance of a threaded connection is important for optimization of the rolling parameters and prediction of the BHA service life in a given drilling condition.

In this paper, a predictive method is presented for fatigue life of a cold rolled threaded connection. A finite element model was developed to simulate the cold rolling process. The resulting deformation and stress states at the root were carried over through makeup of the pin and the box as well as through cyclic bending of the connection. The fatigue life predictions were found to be in favorable agreement with the experimental measurements from full-scale fatigue tests at different bending moment levels applied.
Forced Wetting of Liquids Using Ultrasonic Surface Vibration
Authors: Trapuzzano Matthew A. , Crane Nathan B. , Guldiken Rasim , Tejada-Martínez Andrés
Published: January 2019

Many processes rely on wetting of liquids on surfaces. The way a liquid wets a solid depends on chemistry, geometry, and local energy inputs. Low-frequency surface vibrations can effect wetting changes prompted by droplet oscillations. High-frequency (ultrasonic) surface vibration can also cause a liquid to wet or spread out on a solid, but governing mechanisms are relatively uncharacterized. To investigate, droplets are imaged as they vibrate on a hydrophobic surface over different high frequencies (> 10 kHz). Wetting transitions occur abruptly over a range of parameters, but coincide with surface resonance modes. The wetting change is proportional to droplet volume and surface acceleration, and remains after cessation of vibration, however new droplets wet with the original contact angle. Wetting control has various industry applications, and understanding these basic phenomena will help develop a deeper understanding of how ultrasonic vibration can be utilized to tune the behavior of liquids on any surface.
Modeling for Mineral Redistribution of Coal Blending During Pulverized Coal Combustion
Authors: Saifujjaman Md. , Jeong Kwangkook , Lee Shinku
Published: January 2019

This paper represents an analytical model for predicting mineral particle redistribution of coal blending during pulverized coal (PC) combustion in a pulverized coal-fired boiler. The objective of this research is to develop a computer program to perform the mass balance of total minerals after transformation during combustion. A MATLAB code was developed for coal blending mineral redistribution from single coal mineral redistribution in modular approach based on relative Hardgrove Grindability Index (HGI) of coals. The calculations of the single coal number of ash particles before and after combustion both for excluded and included minerals from the single coal proximate analysis, Malvern analysis, Computer Controlled Scanning Electron Microscopy (CCSEM) analysis, density and composition analysis were designed in a submodule. Utilizing single coal sub-module, the calculations of coal blending number of ash particles before and after combustion both for excluded and included minerals were designed in a module of MATLAB code. The blending modeling was designed to blend up to five sub-bituminous coals. Calculations were made for typical boiler combustion conditions ranging from 1,500K to 2,500K as flame temperature. The organically-associated ash content or mineral grains of each coal smaller than 1 micrometer was not included in the calculation of redistribution modeling. Coal particle fragmentation of blended coal was considered as same as single coal and size dependent phenomena. Partial coalescence model was assumed as more likely to occur. Blended coal was assumed to follow additive rule applied to mineral mass percentage based on sizes and mineral phase regardless grinding of coals separately or after blending if the HGI difference between highest and lowest HGI of coals arranged in ascending order stands within five. The modeling was demonstrated for KPU: AVRA and AVRA: Solntsevsky with specific blending ratio 80:20 and 20:80 respectively. The model for blended coal was validated by the mass balance of minerals before and after combustion. The resulting simplified particle size distribution of mass fraction of KPU: AVRA shows good agreement with experimental results of Kentucky #9 coal because of having a larger amount of included minerals of KPU coal. The model for blended coal mineral redistribution before and after combustion will be developed for the HGI difference between highest and lowest HGI of coals arranged in ascending order becomes greater than five and validated by minerals mass balance before and after combustion. This modeling will be used to predict number of mineral particles and its sizes that is a key parameter as to predict the problems like fouling and slagging and the related reduction of boiler efficiency. The results from this study will be further carried out to investigate ash deposition rates in post-boiler heat exchangers.
Statistical Time Domain Feature Based Approach to Assess the Performance Degradation of Rotary Seals
Authors: Ramachandran Madhumitha , Siddique Zahed
Published: January 2019

In oil and gas industry, machineries and mechanical components are designed with high reliability to meet the demand of the oil field. Rotating machinery is a widely used equipment and any failure of critical components within the machinery could lead to delays and large expenses. Failure of rotary seal is one of the foremost causes of breakdown in rotary machinery and such a failure can affect the other process operations in oil and gas plants. Assessing seal degradation and severity estimation are very important for maintenance decision-making. Extracting meaningful and sensitive features that can show seal degradation from raw signals is a challenging task of degradation assessment. However, no extensive works are dedicated in this area of seals. In this paper, we perform accelerated aging and testing to capture the behavior of seals through their cycle of operation and demonstrated a statistical time domain feature based approach for extracting the sensitive features that can show seal degradation. Out of eleven statistical features extracted, seven extracted features such as mean, RMS, maximum, squared mean rooted absolute amplitude, impulse factor, crest factor, margin factor are found to be significant factors which have a potential to differentiate severity levels in seals. The findings from our work show that our approach has a potential to assess the severity in seals. As a possible extension, extracted features can be used to build a classification model to classify severity in seals which could be of great interest to the users and manufacturers of rotary seals.
Topology Optimization of an Anti Roll Bar of a Heavy Commercial Truck for Vehicle Dynamics and Durability
Authors: Yenilmez Ece , Yasar Ali , Sendur Polat
Published: January 2019

Meeting the stringent requirements on fuel economy and emissions is still a challenge for automotive original equipment manufacturers (OEMs). In this study, we consider the light weighting opportunities of a heavy commercial truck by evaluating the various requirements of its anti-roll bar. First, an MSC.ADAMS model of the truck is analyzed under some standard vehicle dynamics maneuvers and a target for the anti-roll bar is set. A topology optimization study is then performed using Solid Isotropic Material with Penalization (SIMP) method to determine its dimensions and material to meet this target. For this purpose, a finite element (FE) model of the anti-roll bar is developed in order to determine its torsional stiffness using MSC.Nastran commercial software. The advantages and disadvantages of various optimization results are discussed. Finally, fatigue performance of the anti-roll bar is assessed under the road load data coming from various road simulations. The results prove that the simulation tools and optimization methods offer great capabilities to meet challenging requirements of automotive industry.
A Finite Element Approach for Study of Wave Attenuation Characteristics of Epoxy Polymer Composite
Authors: Kulkarni Shank S. , Tabarraei Alireza , Ghag Pratik P.
Published: January 2019

The properties of the inclusions, viz. size, shape, and distribution significantly affect macroscopic properties of a polymer composite. Finite element (FE) modeling provides a viable approach for investigating the effects of the inclusions on the macroscopic properties of the polymer composite. In this paper, finite element method is used to investigate ultrasonic wave propagation in polymer matrix composite with a dispersed phase of inclusions. The finite element models are made up of three phases; viz. the polymer matrix, inclusions (micro constituent), and interphase zones between the inclusions and the polymer matrix. The analysis is performed on a three dimensional finite element model and the attenuation characteristics of ultrasonic longitudinal waves in the matrix are evaluated. The attenuation in polymer composite is investigated by changing the size, volume fraction of inclusions, and addition of interphase layer. The effect of loading frequency of the wave on the attenuation characteristics is also studied by varying the frequency in the range of 1–4 MHz.

Results of the test revealed that higher volume fraction of inclusions gave higher attenuation in the polymer composite as compared to the lower volume fraction model. Smaller size of inclusions are preferred over larger size as they give higher wave attenuation. It was found that the attenuation characteristics of the polymer composite are better at higher frequencies as compared to lower frequencies. It is also concluded that the interphase later plays a significant role in the attenuation characteristics of the composite.
Engineering a Pool Ladder to Prevent Drownings in Above-Ground Pools
Authors: Pierce William H. , Ziernicki Richard M.
Published: January 2019

In the United States, approximately 44 children under the age of five years old drown each year after gaining unauthorized access to above-ground pools via pool ladders. Approximately 704 additional children sustain submersion-related injuries after gaining unauthorized access to above-ground pools via pool ladders. In many cases, these events occurred during brief lapses of adult supervision. The societal cost associated with these deaths and injuries ranges from 134 to 342 million dollars per year. In addition to societal costs, there is also a significant loss in quality of life for near-drowning victims and their families.

Since the 1960’s, several medical studies have been published that discuss children under the age of five accessing above-ground pools and drowning. Several of these medical studies propose solutions to reduce the likelihood of drowning. Despite the proposed solutions in these studies, the rate of such drownings in above-ground pools has not decreased. However, the medical studies do not address how proper and safe engineering design of pool ladders can and should be used to prevent such occurrences.

This paper adds engineering science to these medical studies by including safety engineering principles that can be used to prevent young children from gaining unauthorized access to above-ground pools via pool ladders. Specifically, this paper addresses, hazard and risk assessment, passive safety systems that can be added to pool ladders to prevent drowning incidences, and the economic and technological feasibility of such passive safety systems. This paper shows that the benefits associated with the reduction in societal costs of drowning or near-drowning outweigh the cost of adding passive safety systems to pool ladders.
Life Assessment of Gas Turbine Blades Under Creep Failure Mechanism Considering Humidity
Authors: Soltan Mohammad Lou Bita , Pourgol-Mohammad Mohammad , Yazdani Mojtaba
Published: January 2019

Gas turbines are the most important components in thermal power plants, and these components such as turbine has been studied carefully. Gas turbine components operate predominantly under elevated temperature and high stress, and consequently gradual deformation becomes temporally inevitable. In turbine blades, creep is common failure mechanism, and it is an important factor for design assessment. The gas turbine blade is a component operating at high elevated temperatures, requiring a cooling systems to reduce the temperature. Common power enhancement approach is to spray water into compressor, and it is how humidity becomes an important factor in creep failure mechanism. The humidity variability results in temperature level change during the turbine operation, potentially affecting the blades creep life. In this paper, first different creep life prediction models were classified, and then a new model is proposed for creep life considering humidity based on Arrhenius equation. In our study, failure criterion is rupture. As a case study, the creep life of Nimonic-90 alloy turbine blade was predicted using proposed method and compared with FEA results which collected by literature surveys. Proposed model is capable of predicting creep life with only knowing dry temperature (WAR = 0), and there is no need to measure blade temperature variation during operation. The influence of humidity (%WAR) were studied on turbine blades creep life, and results show that creep life of turbine blade increase with increasing humidity percentage.
A Set of Preliminary Model Experiments for Studying Engineering Student Biases in the Assessment and Prioritization of Risks
Authors: Gernand Jeremy M.
Published: January 2019

Engineering decisions that have the greatest effect on worker and public safety occur early in the design process. During these decisions, engineers rely on their experience and intuition to estimate the severity and likelihood of undesired future events like failures, equipment damage, injuries, or environmental harm. These initial estimates can then form the basis of investment of limited project resources in mitigating those risks. Behavioral economics suggests that most people make significant and predictable errors when considering high consequence, low probability events. These biases have not previously been studied quantitatively in the context of engineering decisions, however. This paper describes preliminary results from a set of computerized experiments with engineering students estimating, prioritizing, and making design decisions related to risk. The undergraduate students included in this experiment were more likely to underestimate than overestimate the risk of failure. They were also more optimistic of the effects of efforts to mitigate risk than the evidence suggested. These results suggest that considerably more effort is needed to understand the characteristics and qualities of these biases in risk estimation, and understand what kinds of intervention might best ameliorate these biases and enable engineers to more effectively identify and manage the risks of technology.
From Customer Requirements to Detailed Design: How Do Product Data Change?
Authors: Rossoni Marco , Colombo Giorgio , Bergonzi Luca
Published: January 2019

Current trends in product development process highlight the increasing adoption of digital data and virtual processes. Nowadays, a huge amount of product data are collected without a clear management strategy and, oftentimes, they dont even cover the whole product development process. A global and integrated planning about information needed to sustain product design process is not a trivial task and, usually, companies underrates this issue. From the perspective of virtualization of processes, and then their automation, the lack of structured knowledge is certainly awful. This paper aims at making a critical analysis how product data evolve throughout the product design or configuration process and how they impact the product development activities. Efficient digital product twin allows companies to virtualize processes and leverage their automation, but it is important to understand how the knowledge management should be carried out. Three case studies, directly experienced by the authors, have been investigated analyzing digital data and virtual tools that allow companies to automate the design process, each one bringing a peculiar perspective of the problem.
Design and Prototype Development of a Reconfigurable Wheelchair With Stand-Sit-Sleep Configurations
Authors: Desai Sumit , Mantha Shankar , Phalle Vikas , Patil Sangram , Handikherkar Vishwadeep
Published: January 2019

Many lower limb disabled, elderly subjects prefer wheelchairs as mobility devices. Transferring such subjects from the wheelchair to and from the bed/toilet seat is one everyday challenge. Caregivers provide manual transfer support to such subjects which increase their caregiver dependence. Lower back pains of caregivers, injury incidences during transfer support are related issues regarding manual caregiver transfer support. Long-time wheelchair users are generally exposed to many health problems associated with idle seated posture in a wheelchair for a long time. The wheelchair with a standing facility allows the user to be able to adjust him to different heights giving enhanced navigations in different situations. Thus, reconfigurable wheelchair built-in with sit-to-stand and sit-to-sleep capabilities can be a handy assistive device for a long time wheelchair users. Thus, the paper presents the design and development of a reconfigurable wheelchair with stand-sit-sleep configurations. Key areas focused on maximizing safety, optimizing the size with minimizing the cost and weight of the wheelchair. The developed model will help in improving the functional capabilities of wheelchair users allowing enhanced independence and quality of life (QoL).