bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using Private Industry Based Projects to Teach an Air Conditioning Technical Elective Course
Authors: Anderson Kevin R. 
Published: February 2021

Abstract
This paper presents the use of private industry based projects to augment the teaching of a senior level thermal design Heating Ventilation Air Conditioning and Refrigeration (HVAC/R) technical elective. The projects describe herein are used to augment the laboratory portion of the course, and act a synthesizing agents allowing students to experience real-world problem solving first hand. The industry based projects are solicited form local industry representatives, whereby mentors from the engineering company are assigned to direct a team of students to complete a given set of action items during the duration of a semester concluding in an end of semester customer design review. The key to this type of learn-by-doing is the active engagement and willingness on behalf of the industry mentors to take time to guide the students via biweekly face to face or web based tag up meetings. This type of experience is invaluable for the students, since it demonstrates the importance of establishing a network of mentors in order to foster life-long learning in the students chosen field of study.
Experimental Study of Direct Metal Laser Sintering: High Cycle Fatigue Life and Process Parameters
Authors: Seyffert Riley , Kaul Sudhir 
Published: February 2021

Abstract
Direct Metal Laser Sintering (DMLS) is a relatively new manufacturing process in additive manufacturing (AM) that fuses powdered metal by using a high-powered laser. Although this process allows manufacturing prototypes without requiring specific tooling, it is challenging to use this process for manufacturing high volume production parts since complex shapes can take a significant amount of build time. Furthermore, manufactured parts also need some amount of post-processing to remove the support material that may be required due to the layer-by-layer build process. This study investigates three process parameters that could be optimized to substantially reduce production time. These three parameters are as follows: build layer thickness, laser scan speed, and laser hatch distance. In order to evaluate the influence of these parameters, manufactured parts made of AISI 316L Stainless Steel are tested for fatigue life and static strength. A three-point bending test is used as per ASTM E466. While none of the three parameters is seen to significantly influence ultimate tensile strength, results indicate that build layer thickness is a significant process parameter that directly affects fatigue life. Furthermore, the interaction between build layer thickness and laser scan speed is found to be statistically significant for high cycle fatigue. However, laser scan speed and laser hatch distance are seen to be statistically insignificant for fatigue life. The initial results of this study indicate that process parameters of DMLS need to be selected judiciously in order to minimize build time while maintaining structural integrity.
Pragmatic Approach to Teaching Introduction to Machine Design
Authors: Anderson Kevin R. , Stover Clifford M. 
Published: February 2021

Abstract
This paper presents examples of teaching Mechanical Design using a pragmatic approach. The pedagogy used herein embeds real-world experience and projects into the curriculum by taking representative case studies from industry and creating course projects. The approach focuses on using sanity checks using free-body diagrams and hand-calculations, materials specification and proliferate used of commercial off the shelf parts supplier catalog data. Case studies from course projects are presented demonstrating the above skill set reinforcement. The assessment of the student work is presented as it is related to the ABET learning outcomes of the mechanical design curriculum track.
Experimental and Numerical Investigation Into Vertical Axis Water Turbine Self-Starting Phenomenon
Authors: Rivera Marcos , Shook Daniel , Foust Emine 
Published: February 2021

Abstract
In rural areas and isolated regions of the world, it is often difficult to obtain reliable access to electricity. A solution often exploited is the use of diesel generators to power homes but that has its negative effects on climate change. In this study, an alternative solution is being investigated, which involves the use of water turbines. For low head applications such as rivers, hydrokinetic turbines are used to harness the kinetic energy in rivers. There are two types of hydrokinetic turbines: horizontal and vertical axis water turbines. The turbine studied in this paper is the Darrieus type vertical axis water turbine (VAWT) which has three straight blades. Darrieus type VAWT primarily use lift forces to operate. Advantages of vertical axis water turbines are simple construction, low cost, and being able to self-orient. However, the Darrieus VAWT has several disadvantages like self-starting problem, low coefficient of performance, shaking, debris accumulation, and cavitation.
In this study, the effect of using thermoplastic polyurethane blades with varying levels of flexibility have been investigated to remedy the self-starting problem. For blade profile, S1046 airfoil is selected. 3-D numerical models were created by using time-accurate Reynolds-averaged Navier Stokes (RANS) commercial solver (ANSYS Fluent 2019 R3). Experimental results show that turbine with lower blade hardness starts to rotate at 0.34m/s while the turbine with higher blade hardness experiences rotation at 0.51m/s.
2 DOF Compliant 3D-PLE System Demonstrating Fundamentals of Vibrations and Passive Vibration Isolation
Authors: Giannakakos Niko , Tekes Ayse , Utschig Tris 
Published: February 2021

Abstract
Mechanical engineering students often learn the fundamentals of vibrations along with the time response of underdamped, critically damped, and overdamped systems in machine dynamics and vibrations courses without any validation or visualization through hands-on experimental learning activities. As these courses are highly theoretical, students find it difficult to connect theory to practical fundamentals such as modeling of a mechanical system, finding components of the system using experimental data, designing a system to achieve a desired response, or designing a passive vibration isolator to reduce transmitted vibrations on a primary system. Further, available educational laboratory equipment demonstrating vibrations, dynamics and control is expensive, bulky, and not portable. To address these issues, we developed a low-cost, 3D printed, portable laboratory equipment (3D-PLE) system consisting of primary and secondary carts, rail, linear actuator, Arduino, and compliant flexures connecting the carts. Most of the educational systems consist of a mass limited to 1DOF motion and multi-degrees of freedom systems can be created using mechanical springs. However, in real-world applications oscillations in a system are not necessarily due to mechanical springs. Anything flexible, or thin and long, can be represented by a spring as seen in torsional systems. We incorporated 3D printed and two monolithically designed rigid arms connected with a flexure hinge of various stiffness. The carts are designed in a way such that two flexible links can be attached from both sides and allow more loads to be added on each cart. The system can be utilized to demonstrate fundamentals of vibrations and test designs of passive isolators to dampen the oscillations of the primary cart.
Designing Composites for Graceful Failure
Authors: Micheal Amany , Bahei-El-Din Yehia , Abd El-Latief Mahmoud E. 
Published: February 2021

Abstract
When inevitable, failure in composite laminates is preferred to occur gracefully to avoid loss of property and possibly life. While the inherent inhomogeneity leads to slow dissipation of damage-related energy, overall failure is fiber-dominated and occurs in a rather brittle manner. Multidirectional plies usually give a more ductile response. Additionally, stiffness and strength as well as cost are important factors to consider in designing composite laminates. It is hence desirable to optimize for high mechanical properties and low cost while keeping graceful failure.
Designing composite laminates with hybrid systems and layups, which permit gradual damage energy dissipation, are two ways proposed in this work to optimize for mechanical properties while avoiding catastrophic failure. In the hybrid system design, combining the less expensive glass reinforced plies with carbon reinforced plies offers a cost-effective product, marginal mechanical properties change and ductile profile upon failure. Hybrid glass/carbon composite laminates subjected to three-point bending showed strain to failure which is double that measured for carbon composite specimens, without affecting the ultimate load.
Energy dissipation mechanisms were also created by building laminates which were intentionally made discontinuous by introducing cuts in the fibers of the interior plies. This created a longer path for damage before cutting through the next ply resulting in double failure strain with marginal reduction in load. The effect of fiber discontinuity in terms of spacing and distribution are among the factors considered.
Mechanical Component’s Dimension Design With Required Reliability by the Monte Carlo Method
Authors: Le Xiaobin 
Published: February 2021

Abstract
Since the main design parameters in a mechanical component design have some uncertainties and should be treated as random variables, the reliability of a component is a better measurement of the safe status of a component. A component will not be reliable unless it is designed with specified reliability. Therefore, the mechanical component design should be a dimension design with the required reliability. The fundamental concept of the Monte Carlo method is to plug-in randomly generated numerical values into the governing equation of a design problem to get a trial result. The Monte Carlo method has become so powerful numerical simulation approach in almost every field such as optimization, numerical integration, and reliability calculation. But for reliability engineering, most of the literature shows how to use the Monte Carlo method to calculate the reliability of a component. This paper will propose the modified Monte Carlo method to determine a component dimension with required reliability. This paper first discusses and establishes typical limit state functions of a component under static loads. These limit state functions cover two failure modes including the failure mode due to strength and the failure mode due to excessive deformation. Then, the procedure and the flowchart of the modified Monte Carlo method will be explained in detail. The provided procedure and the flowchart are easy to be followed for compiling a MATLAB program to conduct a dimension design with required reliability. Two examples will show how to implement the proposed new method for conducting a dimension design with required reliability.
Global Warming Potential Estimations of a Gas Turbine Engine and Effect of Selected Design Parameters
Authors: Dinc Ali , Gharbia Yousef 
Published: February 2021

Abstract
Anthropogenic global warming is a result of greenhouse gas emissions from many human activities such as industry, power generation, transportation etc. Burning fossil fuels generates gas emissions and those emissions should be minimized by careful designs and operations for a sustainable world. The gas turbines are typically used in many applications to generate power and propulsion which require burning of liquid fuel, natural gas etc. In this study, Global Warming Potential (GWP) calculations of a 43 MW class gas turbine engine have been performed. Global warming potential values were calculated for a range of selected design parameters such as turbine inlet temperature, compressor pressure ratio, compressor efficiency, turbine efficiency etc. Those design input parameters were changed ± 5% from an assumed baseline to investigate their effects on the total GWP values due to emissions of CO2, H2O and NOx. The results presented a good guide on the selection of design input parameters in order to cut the emissions down from the design perspective of gas turbine engines. A range of reductions in GWP between 0.46% and 5.86% were estimated by the calculations in this study.
Comparison of Fluid Structure Interaction Capabilities in Finite Volume and Finite Element Based Codes
Authors: Lu Qiyue , Santiago Alfonso , Koric Seid , Cordoba Paula 
Published: February 2021

Abstract
Fluid-Structure Interaction (FSI) simulations have applications to a wide range of engineering areas. One popular technique to solve FSI problems is the Arbitrary Lagrangian-Eulerian (ALE) method. Both academic and industry communities developed codes to implement the ALE method. One of them is Alya, a Finite Element Method (FEM) based code developed in Barcelona Supercomputing Center (BSC). By analyzing the application on a simplified artery case and compared to another commercial code, which is Finite Volume Method (FVM) based, this paper discusses the mathematical background of the solver for domains, and carries out verification work on Alya’s FSI capability. The results show that while both codes provide comparable FSI results, Alya has exhibited better robustness due to its Subgrid Scale (SGS) technique for stabilization of convective term and the subsequent numerical treatments. Thus this code opens the door for more extensive use of higher fidelity finite element based FSI methods in future.
An Eigensystem Realization Algorithm for Modal Parameter Identification of a Vertical-Shaft High-Speed Centrifugal Machine
Authors: Piramoon Sina , Ayoubi Mohammad A. 
Published: February 2021

Abstract
In this paper, we utilize the observer/Kalman filter identification (OKID) and the eigensystem realization algorithm (ERA) techniques to identify the modal parameters of a centrifugal machine. To this end, we use an experimental setup to generate a pseudo-impulse input and collect output measurements which are corrupted by noise. We use the pseudo-impulse input and the OKID to find the Markov parameters of the system. Then we form the Hankel matrix of the system and determine the singular values of the system. A minimum-order, state-space model of the system is realized through the Markov parameters and then the natural frequency, damping ratio, mode shapes, and modal amplitudes at the sensor location are estimated by the ERA. We find three models for three separate cases and validate all the three identified models with the measured data and the Waterfall plot. The identified models are useful for designing passive or active vibration suppression control and fault detection systems. The results confirm that OKID/ERA is a reliable time-domain method for identifying the modal parameters of vertical centrifuge machines.
Robustness Analysis of Parallel Feedforward Control With Derivative (PFCD) Method
Authors: Noury Keyvan , Yang Bingen 
Published: February 2021

Abstract
In this paper, the authors represent the robustness capabilities of their previously implemented parallel feedforward compensator configuration, applicable to nonminimum-phase (NMP) systems. In the previous papers, it was shown how a paralleled feedforward compensator can stabilize a general purpose NMP system with ease. However, the robustness analysis was postponed for a later study. Thus, herein, the robustness capabilities of the proposed configuration in the presence of noise and disturbance are investigated. It will be shown that the main idea behind the stability of the parallel feedforward compensation with derivative (PFCD) methodology comes handy when trying to test for the robustness purposes. At the end, a simulation example is brought to represent the ballparks of the methodology.
Exergoeconomic Analysis in a Cement Production Plant
Authors: Fajardo J. , Mendoza A. , Barreto D. , Valle H. 
Published: February 2021

Abstract
A dry-type Cement Production Plan of 151 Tons per hour was taken as a case of study to implement an exergoeconomic analysis. In this paper, the exergy destruction and the investment costs of the system’s units were calculated to obtain accurate information about the performance of the process, from the exergoeconomic factor and the relative difference cost.
Conventional exergoeconomic analysis showed that the total cost of exergy destruction is 4206537 USD/h. The Calciner and the Rotary Kiln cause 62% of the total cost of the exergy destruction. The lowest values of the exergoeconomic factor were calculated for Calciner (0.01%), Clinker Cooler (0.01%), Rotary Kiln (0.02%), and Raw Mill (0.04%). The significant difference in relative cost was calculated for Calciner (42%) and Rotary Kiln (54.21%). The above implies that this equipment should be considered for an investment that allows the decrease of the exergy destruction cost and the increase of the exergetic efficiency.
Modeling Transient Heat Transfer and Dry-Out Phenomena in Heat Pipes Using Finite Element Analysis
Authors: Özçatalbaş Mustafa , Sezmen Ramazan Aykut 
Published: February 2021

Abstract
Heat pipes are passive two-phase heat transfer devices that used in various heat transport applications because of their high thermal conductance capacities with low temperature differences. One of these applications is aerospace avionics that heat pipes are exposed to transient heat loads. Although heat pipes have been one of the heat removal alternatives for compact electronic devices, they have some restrictions during the usage in such high heat flux areas. In order to use heat pipes as effective heat removal devices, operating heat load range should not be exceeded during the operation of avionics or electronic devices. Out of these operating range, heat pipes no longer perform as effective heat removal devices because of phenomena called dry-out.
In this study, a novel Finite Element (FE) Analysis Method was developed to model transient heat transfer behavior in heat pipes including dry-out phenomenon. Transient heat transfer analysis using Finite Element Method (FEM) was conducted to investigate heat pipe thermal performance considering heat flux dependent thermal conductivity under randomly varying heat inputs, which were assumed as heat dissipation of an electronic device. Validation of the FE model was done by using the results given in the literature.
Heat pipe was made of Al with a length of LHP = 200 mm. Heat flux and convective heat transfer boundary conditions were used at the evaporator and condenser sections, respectively. Effective thermal conductivity of heat pipe, keff, was calculated by using the heat input depended thermal resistance, Rth, values given in literature. Under transient heat loads, heat flux dependent effective thermal conductivity was defined using user defined subroutines to simulate the dry-out. The transient heat transfer analysis was conducted using ABAQUS commercially available software. Temperature differences between evaporator and condenser sections, ΔT = Te−Tc, and thermal resistance, Rth, values are calculated for varying heat input values and compared with the results that provided in literature.
Maximum Condensable Pressure in a Sealed Container With Arbitrary Temperature Distribution
Authors: Watjen J. I. , Schifano M. T. , Sexton M. N. 
Published: February 2021

Abstract
Pressure vessels and sealed canisters are designed to maintain seal integrity under a maximum internal pressure. When the temperature inside the canister rises, the internal pressure rises accordingly. The presence of condensable liquid-vapor mixtures can create a strong relationship between the pressure and temperature. An isothermal container admits a straightforward thermodynamic pressure calculation; however, large temperature gradients inside the container require complex multiphase conjugate heat transfer calculations to predict accurate pressures. A simplified prediction using the peak internal temperature to find the saturated pressure of the condensable fluid may introduce unrealistic pressures when significant fluid mass exists in a cooler location of the container.
This work presents methodology to calculate the pressure of a condensable fluid in a sealed container with large internal temperature differences using a two-temperature approach to predict saturated boiling and superheating of the vapor phase. An arbitrary temperature distribution allows for pressure calculations by considering the expected location of the liquid mass and the peak internal temperature. An enthalpy balance provides the effects of the temperature distribution and the peak pressure condition is easily predicted using the proposed method. This work provides a means to calculate the maximum internal pressure of a sealed container with a condensable fluid without the need for complex multiphase computer modeling.
Kit Based Motion Generator for a Soft Walking Robot
Authors: Schiller Lars , Maruthavanan Duraikannan , Seibel Arthur , Schlattmann Josef 
Published: February 2021

Abstract
In order to control high-level goals such as walking speed and direction or position of legged robots, a locomotion controller is required. This complicated task can be solved in many different ways. The approach presented here selects the optimal gait pattern from a discrete, predefined set of possibilities to get closer to a given target position. The method is based on an off-line component: elementary gait patterns are generated by trajectory optimization using a simulation model, and an on-line component: for given robot and target positions the optimal next elementary gait pattern is chosen based on a minimization problem, and the joint space references are derived from it. To ensure feasible subsequent poses, the elementary patterns always begin and end with one and the same pose, so that they can be placed on top of each other like Lego bricks. A great advantage of this method is a straightforward transition between different motion modes, such as switching from trotting to crawling. It is discussed how many different elementary patterns are needed to ensure a stable locomotion control. Finally, in simulation and experiment, it is shown that the robot can master any obstacle course using the proposed locomotion controller.
Augmentation of Fixed Gain Controlled Infinite Dimensional Systems With Direct Adaptive Control
Authors: Balas Mark J. 
Published: February 2021

Abstract
Linear infinite dimensional systems are described by a closed, densely defined linear operator that generates a continuous semigroup of bounded operators on a general Hilbert space of states and are controlled via a finite number of actuators and sensors. Many distributed applications are included in this formulation, such as large flexible aerospace structures, adaptive optics, diffusion reactions, smart electric power grids, and quantum information systems.
In this paper, we focus on infinite dimensional linear systems for which a fixed gain linear infinite or finite dimensional controller is already in place. We augment this controller with a direct adaptive controller that will maintain stability of the full closed loop system even when the fixed gain controller fails to do so. We prove that the transmission zeros of the combined system are the original open loop transmission zeros, and the point spectrum of the controller alone. Therefore, the combined plant plus controller is Almost Strictly Dissipative (ASD) if and only if the original open loop system is minimum phase, and the fixed gain controller alone is exponentially stable. This result is true whether the fixed gain controller is finite or infinite dimensional. In particular this guarantees that a controller for an infinite dimensional plant based on a reduced -order approximation can be stabilized by augmentation with direct adaptive control to mitigate risks.
These results are illustrated by application to direct adaptive control of general linear diffusion systems on a Hilbert space that are described by self-adjoint operators with compact resolvent.