bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancing Access to Water in Mexico City and Its Peri-Urban Area Through User Centered Design
Authors: Negrete Rojas David , Rodriguez-Tenorio J. Carlos , Ramos Álvarez Adrielly Nahomeé , Ramirez-Reivich Alejandro C. , Corona-Lira Ma. Pilar , Borja Vicente , Soler Anguiano Francisca Irene
Published: January 2022

Lack of water in Mexico City and its peri-urban area has been an increasingly worrying matter in the last few years and has been addressed through multiple government and NGO initiatives such as supplemental delivery via water trucks, rainwater harvesting, intermittence in water services and pipeline network maintenance. However, the rapid and unstructured development of the urban spot has exacerbated the problem, rendering these solutions ineffective.

Due to the complexity of the problem, solutions may be more impactful if they focus on fixing or creating effective interactions among the elements of the system — interactions in which the main element is the user. This paper presents a design proposal created from the observations made in Mexico City. Design Thinking was used by understanding the users’ needs and the interactions between the agents through three main phases: Approach and definition of the problem, Prototyping stage and Final proposal explanation.

The proposal and research results could be used and extrapolated to other cities and communities around the world, as water availability and quality are a global challenge and can be tackled in similar ways.
Kinetic Study of Nitric Oxide Formation at Atmospheric and High-Pressure Conditions for Different Primary Gaseous Fuels
Authors: Alam Fahd
Published: January 2022

Several recent detailed chemical kinetic models have been computationally investigated to assess the predictive competency of nitrogen oxides for gaseous low carbon number fuels. The objective is to understand how the recent models perform in predicting nitric oxide (NO) emissions at atmospheric and high-pressure including rich flames. Three different detailed kinetic models are considered for this assessment. For kinetic analysis, we employed one-dimensional laminar premixed flame (LFS) calculations using kinetic tool Cantera (v2.4) against measurements of laminar flame speed and NO speciation. The study is conducted at atmospheric and higher pressure (10, 14.6 atm) for varying equivalence ratios. In general, the kinetic models satisfactorily reproduced the LFS data. For NO prediction, acceptable emulation of measured data is observed at 1 atm for lean to slightly rich flames (Φ = 0.5–1.05), while greater discrepancies emerge at the rich flame conditions. At higher pressure, significant underprediction are also observed across for all three models. We found that prediction discrepancies at the rich mixtures are primarily linked to the prompt-NO pathways. Furthermore, rate of production analysis manifests that a consensus for the main reaction channels for NO at rich flames is yet to be established for these recent models.
Graphene Oxide / Nanodiamond Nanocomposites Characterized via Particle Dispersion and Micro- and Nanoscale Mechanical Properties
Authors: Abdelrahman Mustafa , Jewell Slade C. , Elbella Abdalla , Timpe Shannon J.
Published: January 2022

Polystyrene matrix nanocomposites were formulated using a custom nano particle consisting of nanodiamond covalently bonded to graphene oxide. Dispersion and mechanical property results for the nano composite are compared to those results for the neat polymer as well as for a nanocomposite infused with graphene oxide only. Dynamic light scattering was performed to determine the size of particles and the results showed that the custom nanoparticle reduced agglomeration by about 50% as compared to the graphene oxide alone. Microscale Vickers hardness testing revealed that neat polymer as well as the two nanocomposite samples all have similar hardness while nanoscale atomic force microscopy revealed that the neat polymer samples have the highest stiffness on average and the custom nanoparticle composite samples have the lowest stiffness. This difference in mechanical behavior with scale is attributed to local defects at the particle/matrix interface.
Integration-Free Frameworks for Exploring Strain Energy Density in Rubber-Like Elasticity
Authors: Akbari Ramin , Dargazany Roozbeh
Published: January 2022

Elastomers have been an active field of research during the past years for their extensive use in the industry. They are characterized by their unique hyper-elastic behavior, which can recover from a large amount of deformation. Constitutive models in rubber-like elasticity are essentially classified into 1) phenomenological and 2) physical-based models. The phenomenological models are based on direct experimental observation. Contrarily, Physical-based models come with a mathematical origin and employ physical hypotheses to describe a network of polymeric chains. As outlined in the literature, the accuracy of structure-based models has fallen behind the phenomenological models, despite their physical justification. The reasons for this unexpected fact lie in the simplified and superfluous assumptions that exist in the derivation of a closed-form expression for formulating material behavior. Moreover, physical-based models are calibrated through a nonlinear optimization schemes that, in essence, come with uncertainty. This uncertainty can be more affected by the complexity of the model. In this paper, we exploit an inverse approach to improve the accuracy of physically motivated models. To this end, We hold the virgin postulation in these models by considering the strain energy function in terms of two state variables that have been hypothesized to correspond to the kinetics of polymeric chains. Accordingly, we utilize B-spline interpolation to shift the unknown core functions of the strain energy potential to the macro-scale. Following this, we define a loss function based on the experimental data which is the macroscopic stress and use the simple linear least-square technique to determine these functions. In this way, we converge to a linear system of equations that is easy to solve and gives the best possible fit with data. Hence, In this numerical framework, we avoid unnecessary assumptions as far as possible and also nonlinear optimization for constitutive modeling. Finally, we compare the performance of the proposed methods with well-known models in the literature.
A Multiobjective Optimization Based Approach for Producing Manufacturable Structures From Topology Optimized Designs
Authors: Cerda Michael , Hamel Josh
Published: January 2022

The drive to produce low-cost structural designs that also have excellent engineering performance has led to a rise in the use of topology optimization (TO) methods. As a result, many commercially available computer aided design (CAD) software packages now include TO capabilities. Topology optimization can produce designs with superior performance by optimally allocating a budget of material within a given design domain, but the geometric complexity associated with many TO generated solutions makes realizing these designs via traditional (e.g. subtractive) manufacturing processes quite challenging. Additive manufacturing (AM) processes can effectively realize TO generated designs, but AM is not yet a universally acceptable manufacturing option for many applications. This paper presents the details of a more generally applicable design framework for using commercially available TO tools and an iterative procedure to create structurally optimized designs that are also manufacturable. This iterative process uses a TO solution to a structural design problem generated by a commercial CAD package as a target solution, and then successively adds optimally sized traditionally manufacturable features to the original structure until the engineering performance of the component is as close to the TO generated target design as possible in a multiobjective sense. This approach was tested on a two-dimensional structural design case study to demonstrate its implementation, effectiveness, and general applicability to wide variety of structural design problems.
Development of an Origami-Inspired Robot Using Self-Folding Technique
Authors: Shin Minchul
Published: January 2022

This report is about a self-folding origami-inspired robot that was created using a layer of paper, PVC film and 3D printed mechanism. Its inexpensive materials and rapid production allow the robot to have benefits and great potential in conditions where the robot needs to be disposable and can be mass produced. This report presents the principles of controlling the angle of paper folding, transporting kinetic energy from the energy source to the legs. This robot can carry, push, and pull each of 155.28%, 48.03%, and 58.39% of the weight of the whole system.
Distance/Online Engineering Education During and After COVID-19: Graduate Teaching Assistant’s Perspective
Authors: Kumar Vishnu
Published: January 2022

The COVID-19 pandemic has forced universities across the globe to switch to distance/online mode of teaching since Spring 2020. The engineering college teaching community including graduate teaching assistants were severely affected by this change. Even though numerous articles cite a variety of strategies for online teaching for full time instructors, it has been identified that there are limited resources tailor made for graduate students who are teaching engineering classes. This article tries to bridge this gap by exploring some strategies for graduate teaching assistants to help them prepare for online classes and overcome the challenges posed by online/distance education from a graduate student’s experience and perspective.
The Impact of Manufacturing Fixation in Design: Insights From Interviews With Engineering Professionals
Authors: Bracken Brennan Jennifer , Simpson Timothy W. , Miney William B. , Jablokow Kathryn W.
Published: January 2022

Designing for any advanced manufacturing technology necessitates looking beyond the current manufacturing limitations that have constrained one’s previous design ideas. Moreover, fixation on existing and/or familiar manufacturing processes may prevent both the designers and project managers from considering new advanced manufacturing processes. We refer to this type of design fixation as Manufacturing Fixation in Design (MFD), and we explore its impact via semi-structured interviews with nine practicing engineers and engineering managers. These individuals have all personally experienced, or been impacted by, MFD in some form over the course of their careers, which span 17 different companies. We elicit their perceptions of MFD’s impact on manufacturing choices and observations as to when MFD occurs in the design process and how it has influenced past design and manufacturing choices. Our study reveals MFD is frequently experienced as a tendency to select manufacturing processes with which a designer is most familiar without considering other manufacturing options. This can restrict the use of advanced manufacturing technology — a phenomenon several interview subjects have directly observed. Methods of leveraging these findings to expedite the adoption of advanced manufacturing are discussed. Additionally, ways to overcome and mitigate MFD are proposed and identified as topics for future research.
Experimental Investigation on Surface Integrity in Micro-End Milling of Network-Structured TiBw/TA15 Composites
Authors: Yang Minghui , Huang Yu , Peng Fangyu , Rong Yan , Deng Ben , Han Fuqiang
Published: January 2022

TiBw/TA15 composites with network architecture is a new class of metal matrix composites with superior mechanical properties. It has great potential to be applied in the aerospace and automotive fields. However, it is still a challenge to obtain the good surface quality in micro-machining of this kind of composite material. Compared with the micro-end milling experiments of non-reinforced TA15 alloy, this paper investigates the influences of cutting parameters and machining mechanism on the surface integrity in micro-end milling of the network-structured TiBw/TA15 composites, and the variations of cutting force, specific cutting energy, surface roughness and surface topography are analyzed. The results show that both brittle and ductile cutting mechanisms are involved in the machining process. The defects (such as voids, pits, microcracks, protuberance) on the machined surface are mainly distributed in a network-structured pattern. And then the detachment of the deboned or fractured reinforcements from matrix can generate the deep and meteor-like grooves emanating from the network-structured areas. It is suggested that the high spindle speed (not less than 30,000 rpm) and small feed rate (not more than 3μm/tooth) can deteriorate the machined surface quality.
Investigation on Tool Performance in Ultrasonic Vibration Assisted Cutting SiCf/SiC Ceramic Matrix Composites
Authors: Xiong Yi-feng , Wang Wen-hu , Shi Yao-yao , Jiang Rui-song , Huang Bo , Liu Cong , Liu Xiao-fen , Zhu Xiao-xiang
Published: January 2022

Ceramic matrix composites have been a promising advanced material due to its superior properties such as high strength and high temperature resistance. However, due to the high hardness and brittleness of reinforcement and matrix, the machining of this new material still needs to be solved. In this study, investigation of tool performance was conducted on SiC fiber reinforced SiC ceramic matrix composites using ultrasonic vibration assisted machining technique with taking advantages of decreasing cutting force, reducing tool wear and improving machinability. Three types of tools including PDC, brazed diamond tool and electroplated diamond tool were tested by carrying out ultrasonic vibration assisted milling-grinding experiments. The milling-grinding force, material removal volume and machined surface roughness was comparatively studied at the same machining conditions. From experimental results, it was found out that the wear mechanism of PDC and electroplated diamond tool was mainly abrasive wear and fracture of grains while pull-out of grains could be additionally found for brazed diamond tool. The PDC had a better tool performance with material removal volume being 12 times and 50.63 times as larger as that of brazed diamond tool and electroplated diamond tool respectively. It was recommended that the PDC could be used for high precision machining and brazed diamond tool could be chosen for rough machining or semi finish machining in ultrasonic vibration assisted milling-grinding SiC fiber reinforced SiC ceramic matrix composites.
A Two-Phase Flow Study on Carbon Dioxide Bubbles Evolution in Direct-Methanol Fuel Cells With Degassing Channels
Authors: Osman Sameer , Ahmed Mahmoud
Published: January 2022

Low-temperature fuel cells have the potential to be used in portable and automotive applications, and the direct-methanol fuel cell is a good candidate for such applications as the fuel is in the liquid phase, making it easy to store and handle. Active direct-methanol fuel cells (DMFCs) operate on a liquid methanol solution as a fuel that is pumped to the anode flow channels. Gaseous carbon dioxide can accumulate in the anode channels and block the diffusion layer (DL), limiting the transport of reactants through the DL to the functional layer. This causes a drop in the rate of reaction and therefore limits the maximum current density achievable by the cell. A degassing channel concept is investigated in this study to collect Carbon dioxide bubbles and keep them away from the main channel. A 3D two-phase flow model is developed and validated to investigate bubble development and actuation to the degassing channel. Different wettability conditions for the degassing channel are investigated, and the resulting bubble development pattern is analyzed for the expected effect on mass transport of reactants to the DL. Results indicate that the use of a degassing channel significantly improves the transport of reactants in the main channel, which in turn improves the cell’s performance. Furthermore, using a degassing channel with a slightly hydrophobic treatment achieved around 37% faster bubble actuation rate from the main channel, compared to a degassing channel with plain wettability. However, this treatment created longer bubble slugs that travel about 25% slower than in the plain case. In summary, using this configuration will improve the mass transport of reactants to the diffusion layer, at the expense that bubbles will be extracted more slowly from the flow field overall. These findings create the opportunity to improve the performance of DMFCs by the improvement of mass transport of reactants on the anode side.
Multi-Objective Optimal Kinematic Design of Composite Transverse Leaf Spring McPherson Suspension
Authors: Zhang Junhong , Long Feiqi , Lin Jiewei , Zhang Yiming
Published: January 2022

A multi-objective optimization method is proposed to overcome the shortcomings of the traditional method which establish the multi-body dynamic model frequently. A multi-body dynamic model of a McPherson front suspension with composite transverse leaf spring is developed in ADAMS/Car. The parallel travel simulation result shows the toe angle, camber angle, kingpin inclination angle, and caster angle deviate from design targets. To converge to the design value and reduce the variation range, the influences of suspension hard points on the kinematic parameters are studied. Eight design variables are identified out of 36 hard point coordinates according to their sensitivity to the target. The root mean square values of the kinematic parameters are set as the optimization objectives. The quadratic polynomial is employed to build the response surface of the kinematic parameters to design variables. The Pareto optimal solution set is obtained using the NSGA-II algorithm. The optimization merges the gap between the initial values and the design targets from [0.3066, 0.3425, 12.6201, 4.7352] to [0.2936, 0.3463, 13.1535, 3.9588] with variation range of [89.42%, 29.46%, 12.05%, 15.77%]. It is shown the method can effectively improve the precision of the dynamic model and lays a foundation for the research of suspension handling and stability performance.
Manufacturing and Performance Assessment of Solar Photo-Voltaic Modules by Adopting Various Heat Dissipation Techniques: A Review
Authors: Subhan Abdul , Mourad Abdel-Hamid I.
Published: January 2022

One of the major drawbacks in the performance of PV modules is their operating temperature which grows linearly with the irradiance. It is well known for a fact that solar cell temperature is directly dependent on the electrical conversion efficiency of a PV module. The extra heat generated by the PV module due to the absorption of incoming solar irradiance is seen as an electrical loss to the overall output of the system and also results in thermal stresses getting developed. Therefore, to tackle this issue of overheating, the focus of PV module research in the past two decades has always been to analyze & develop various kinds of Heat dissipation techniques to reduce its cell temperature thereby increasing the maximum power output of the panel. This work presents a comprehensive review of the technologies adopted by researchers for heat dissipation of PV systems by both active and passive cooling techniques such as hybrid Solar PV/T system, usage of phase change materials, improved heat exchanger channel design, heat sinks, jet impingement cooling, thermoelectric cooling etc. This manuscript considers also the most economical, feasible and cost-effective heat dissipation /cooling technique of the PV modules and finally to give a perspective of how feasible they are in being adopted by the manufacturing sector. The outcomes of this study can help researchers, designers and engineers to analyze and come up with a practical solution in development of PV systems.
Dynamics of Flow and Heat Transfer Around Two Circular Cylinders of Different Diameters in Tandem Subjected to Forced Convection
Authors: Homsi Rami , Islam Md , Fatt Yap Yit , Janajreh Isam
Published: January 2022

Two-dimensional numerical simulations for heated and unheated flows over two circular cylinders of different diameters in tandem are conducted. The study is conducted for Re = 150 and temperature ratio 1 ≤ (T* = Ts/T∞) ≤ 2.3. The study is limited to spacing ratios in the range 2 ≤ L/Dd ≤ 8 and diameter ratios 0.5 ≤ Du/Dd ≤ 2. The effect of heating on the flow is captured by modelling the thermophysical properties of the fluid fitted as polynomial functions of temperature. The flow features are visualized by plotting the streamlines and velocity magnitude contours. These flow patterns are also discussed based on the reattachment and co-shedding regimes which are classification found in literature. The effect of varying geometrical parameters on the flow in terms of change of regime is discussed. Furthermore, the drag coefficient (Cd) on both upstream and downstream cylinders is presented as a function of spacing and diameter ratios. Additionally the average surface heat transfer coefficient (h) is presented for the interval of spacing and diameter ratios stated. Results show that the presence of an upstream cylinder led to reduction of Cd on the downstream cylinder to a value lower than that of single cylinder for all cases studied. Heating both cylinders causes Cd on both cylinders to become less sensitive to a change in L/Dd, and increasing Du/Dd is found to decrease h on both upstream and downstream cylinders.
High Temperature LVDT Design and Modeling
Authors: Gao Yuan , Ban Heng , Fleming Austin
Published: January 2022

The linear variable displacement transducer (LVDT) is a widely used displacement sensor in engineering. The ability to work in a high-temperature and radioactive environment is an advantage of LVDT’s application in nuclear engineering. This paper utilizes the FEM to explore the LVDT design and performance space. Model validation is accomplished by comparing the simulation results with published experimental results. Important parameters, such as magnetic core permeability, core radius, and coil thickness, are discussed based on simulation results. The influence of temperature is investigated when the permeability is larger than a certain value (permeability saturation point). The FEM model agrees with the experiment well, and it can help to explore the characteristic of LVDT and guide the future design. For high-temperature LVDT designs, selecting the magnetic core material with permeability higher than the permeability saturation point in the whole measurement range is essential for steady output.
Pull-Out Force of Bean Plants Grown in Agar With Fluidic Microchannels
Authors: Azlan Abdul Aziz , Lim Kai Boon , Zuruzi Abu Samah
Published: January 2022

Agar have long been used as a growth media in biology and medicine. This contribution reports on the results of pull out force of bean plants grown in agar with nutrients-filled microchannels. A jig was developed for pull-out of individual plants grown in agar with nutrients-filled microchannels. Similar tests were carried out on plants grown in agar without nutrients as comparison. A conventional mechanical test machine was used to perform the pull out on days-old Black Eye bean (Vigna Unguiculata) and Mung bean (Vigna Radiata) plants. During pull out tests, load increases linearly with displacement until a maximum load is reached which corresponds to the observed pull-out of the hypocotyl from the agar. In general, load at pull out increases with age of plants. However, when grown without nutrients bean plants develop long tap root length but that does not necessarily translate to larger pull-out force. These observations suggest agar with channels is a suitable platform to study effect of nutrients on root structure and pull-out force.
Computational Fluid Dynamics and Students’ Creativity
Authors: Mokhtar Wael A.
Published: January 2022

One of the known definitions of engineering is the creative application of principles. Also, one of the recent trends in engineering education is a more comprehensive view of design skills, ABET, Student Outcomes 2. The design constraints have been expanding beyond the technical requirements to include public health, safety, and welfare, as well as global, cultural, social, environmental, and economic factors. Creativity and deign are two sides of one coin. In the published literature, there is a debate if creativity can be taught and grow in students or it is a personal gift for a limited number of future engineers. In this work, Computational Fluid Dynamics (CFD) is discussed as a tool that can grow the creativity kills in students. With the enhanced simulation environment of CFD tools, students can expand their design skills and grow their creativity beyond the limitations of physical modeling.
A Framework for Integrating Reliability, Robustness, Resilience, and Vulnerability to Assess System Adaptivity
Authors: Rostami Milad , Bucking Scott
Published: January 2022

The growing effort to improve a mechanical system’s performance with a sustainable perspective has created more complexity due to the need for additional technological subsystems. Increased complexity could result in new failure modes for systems making performance assessment more challenging. Therefore, it is essential to develop frameworks to assess performance based on a broader approach beyond single indicators. However, when considering reliability, resilience, robustness, and vulnerability (3RV) concepts as single mathematical-based models for assessing a system’s performance, designers are confronted by similarities between these concepts. In this regard, integrating these four concepts and developing a comprehensive variable (herein called system adaptivity) could better unify 3RV as a single objective function. Consequently, this study presents independent definitions for each concept and identifies common aspects and interrelationships between them. Finally, a system adaptivity objective function will be defined quantitatively by evaluating identified characteristics and internal and external relations for each concept in the previous step. This new prospect could represent a system’s adaptivity as an integrated framework towards different defined failure scenarios.
Self-Driven Transport of Liquid Droplets in V-Shaped Grooves Due to Asymmetric Evaporation
Authors: He Xukun , Cheng Jiangtao
Published: January 2022

Evaporation and transport of a liquid droplet are generally regarded as two independent procedures in various scenarios. Here, we reveal a self-propelled mechanism allowing for the directional transport of an evaporating droplet between two non-parallel hydrophobic surfaces with dihedral angle α. Based on force and energy analyses, the confined droplet of volume V would drift towards an equilibrium position of distance le from the cusp with the lowest Gibbs free energy G. And the directional motion of the evaporating droplet results from the consecutively decreasing le, which is scaled as ∼α−1V1/3 during droplet evaporation. Herein the droplet motion could be characterized by the creeping mode and the slipping mode. Thus, the self-driven behavior of droplet is ascribed to its relaxation process from the stretched regime to the equilibrium regime. Our finding on the intrinsic mechanism of droplet actuations sheds light on a novel approach to manipulating the confined droplet behaviors in a passive and decisive fashion.
An Approach for Safeguarding Autonomous Mobile Robots Using Monitoring Tools
Authors: Müller Manuel , Schinzel Natalie , Jazdi Nasser , Weyrich Michael
Published: January 2022

Autonomous mobile robots with manipulators are becoming increasingly important in industry because they are the most flexible type of mobile robots. Therefore, these mobile robots are employed in dynamic, heterogeneous and partly structured environments. However, as depicted in ANSI/RIA R15.08-1-2020, new safety requirements focusing the fitness of the mobile robots to its operational scenarios arise. In contrast to fenced industrial robots, mobile robots need to reason about their environment, specifically the monitored space and adapt accordingly. However, since the monitored space is often limited, today’s autonomous industrial mobile robots type C (IMR-C) as R15.08-1-2020 names this kind of robots waste much potential reducing their pace of work due to limited monitored space. To counteract this issue, we first analyze the effects of limited monitored space using system theoretic process analysis (STPA) and then come up with a novel monitoring tool closing the blind spots of the IMR-Cs. The comparison of the STPAs with and without external monitoring tools show risk reduction in the original loss scenarios but new loss scenarios and consuming effort in order to assemble them. We present a methodology to weight the gains and losses of assembling an additional monitoring tool using the Digital Twin. The evaluation of our prototype in a goods receipt scenario shows promising results.
The Encapsulation Effect on Thermal Performance of Micro-Encapsulated Phase Change Materials During Energy Absorption
Authors: Benner Jingru Z. , Shannon Rebecca C. , Wu Wentao , Metsack Austen P. , Shen Lu , Zhao Jingzhou
Published: January 2022

Understanding the performance of the thermal storage materials is required to successfully meet the needs of next generation concentrating solar power projects. This study focuses on the thermal characteristics of the micro-encapsulated phase change material (MEPCM) with metallic core under high temperature. A numerical model was developed and verified to study the transient heat absorption process of MEPCMs made of tin, aluminum and copper core. Convective heat transfer rate, total energy absorption and volumetric energy density were presented. The effect of encapsulation on theses variables was analyzed under various boundary and initial conditions. Its impact on characteristic time variables was discussed. The method presented can be adopted to analyzing both manufacturing and application processes for MEPCMs of various compositions, during which melting and solidification happen. Given certain operating conditions, the results from the model can be referenced to obtain optimal thermal performance of these materials.
Spindle Bearings Fault Diagnosis Technique Based on Integration of Zero Resonator Frequency Filter and Discrete Wavelet Packet Transform
Authors: Mwelinde Avitus Titus , Jin Hongyu , Banzi Jamal , Fu Hongya , Han Zhenyu
Published: January 2022

Spindle bearing is one of the machine elements in the spindle that is mostly vulnerable to failure. Its failure may result into total machine tool breakdown and other associated catastrophic consequences. An early identification of the failure is emphasized for reducing extreme damages of the machine tools. This study develops a novel hybrid algorithm combining the Zero Resonator Frequency Filter (ZRFF) and the Discrete Wavelet Packet Transform (DWPT) for early spindle bearing fault detection and diagnosis. The integrated method uses the ZRFF as the first level of de-noising the vibration signals and the DWPT for clear extraction of crucial periodic impulse features that are not easily visible from the first de-noising. The obtained frequency spectrum gives a dominant peak line which corresponds to the fault frequency of interest. An optimum wavelet decomposition level is also determined using the minimum Shannon entropy criteria. The experimental datasets from Case Western Reserve University (CWRU) and simulated signal were used to test the validity of the proposed algorithm. The proposed algorithm had superior performance in terms of computational efficiency (45s) and high classification accuracy of the bearings faults when compared with other methods.
The Influence of Sustainable Cooling Strategies and Uncut Chip Thickness on Surface Integrity in Finish Machining of Ti-6Al-4V Alloy
Authors: Chen Guang , Chen Shi , Schoop Julius , Caudill James , Jawahir I. S.
Published: January 2022

In this work, orthogonal cutting experiments with varying uncut chip thickness (10–50 μm) were performed under a range of sustainable (dry, MQL and cryogenic) cooling strategies to study the combined ploughing and cutting processes for Ti-6Al-4V alloy. With the increasing uncut chip thickness, from 20 μm to 50μm, the principal force increased approximately linearly from 200 N to 480 N. However, the thrust force increased only slightly from 400 N to 500 N. For the minimum uncut chip thickness (10 μm), the forces at the dry and MQL conditions generated fluctuation due to the unstable cutting process, which means that the materials accumulated ahead of cutting edge periodically due to the combined effects of sliding, ploughing and cutting. The thickness of the grain refinement layer with uncut chip thickness of 10 μm was thicker than those produced with larger uncut chip thickness, i.e., more material was ploughed to machined surface at uncut chip thickness of 10μm than those at larger uncut chip thickness conditions. The measured micro-hardness of machined surface at the uncut chip thickness of 10 μm at different cooling/lubrication conditions was about 380–395 HV, higher that those with uncut chip thickness of 50μm (350–360 HV). The increase in surface hardness at the small uncut chip thickness was mainly caused by the grain refinement related to the sever plastic deformation (SPD) due to the ploughing effect. Overall, orthogonal machining of Ti-6Al-4V alloy with cryogenic cooling and small uncut chip thickness exhibited finish machining surface integrity and mechanical behaviors.
Heat Transfer From a Short Cylinder Situated Parallel to an Air Stream
Authors: Molki Majid
Published: January 2022

This work presents heat transfer for isothermal cylinders situated parallel to a uniform flow, and it compares the local and average heat transfer coefficients to several experimental data. The computations consider air as the working fluid, but the paper proposes an extension of correlations to other fluids. In this study, the cylinder length-to-diameter ratio is equal to one, and the flow Reynolds number ranges from 5000 to 42,000. The results show that the convective heat transfer coefficient for the cylinder’s front face increases radially outward in agreement with the available experimental data. The theoretical stagnation point Nusselt number agrees with the present results. The flow separation and recirculation on the cylinder side influence the local heat transfer. The wake region behind the cylinder fluctuates, but no vortex shedding is visible like a cylinder in cross flow. The heat flux on the cylinder lateral surface shows slight azimuthal variations possibly caused by the wake region oscillations. Local and average Nusselt number and heat flux contours are among the results presented in this paper.
Investigating the Effect of Twisting and Printing Orientation on the Toughness of 3-D Printed Parts
Authors: Murali Hari , Kamaraj Abishek B.
Published: January 2022

Additive manufacturing (3-D printing) has become a critical factor in the aerospace, biomedical, and automotive industries. The ability to manufacture complex shapes quickly and easily while also being cost-effective and environmentally friendly has made 3-D printing technology a promising step in the future of engineering. However, a key drawback to the technology is the reduction of strength and toughness of printed parts in the vertical direction (perpendicular to the layer line). Due to the weak interfacial bonding and very low infill density, printed parts are often lacking in strength and toughness. While these issues are not a concern for 3-D prints at lower angles, they make printing at higher angles much more difficult and it has become a consensus in the 3-D printing community that prints above 45 degrees are not advisable for load-bearing applications. This severely limits the capabilities of 3-D printed objects as the most complex shapes require high printing orientations. However, while a high printing orientation may have a detrimental effect on the prints, it is unknown if twisting the angle of the prints while simultaneously changing the printing orientation will have a positive or negative influence on the toughness and strength of prints. In this experiment, we seek to determine if a change in the twisting orientation or printing orientation will affect the toughness of the 3-D prints. We followed a designed experimental study that included two factors at four levels and the parts were made of PLA polymer material with different twisting and printing orientations on a Creality FDM 3D printer. The tensile strength and toughness of the printed parts were tested using a universal tensile testing machine. Our findings showed that the twisting orientation of 30 degrees increases the toughness of prints. This was evident even when the printing orientation is above 45 degrees. By varying the twisting angle, it was found that we can make more complex prints much tougher and easier to make.
Modeling and Analysis of Gear Tooth Replacement System Against Breaking of Single Tooth
Authors: Patel Dhiren , Virdi Gurprit Singh T. , Dhass A. D.
Published: January 2022

A gear is a mechanical machine part that transmits motion by successfully engaging teeth and gives the impression of positive action by coordinating and interlocking precise effort to achieve the desired result. Gear design necessitates a thorough investigation, and the loads, as well as the gear parameters, were determined by trial and error. When a single tooth on any gear breaks, the transfer of power is halted, resulting in material, time, and cost waste. The design and development of spur gear with teeth portability is the subject of this research paper. ANSYS is used to perform gear design analysis. To ensure precision, a wire cut electric discharge machine is used to cut each tooth, which is then assembled into gear using a gear blank, cover plate, nut, and bolt. The results of the analysis performed in the program Ansys 15.0 show that the proposed portable tooth spur gear can withstand maximum principal stress of 1.1886 × 108 Pa and total deformation that will occur at this stress 5.7897 × 10(−6) m. If the portable tooth spur gear is used, the cost of replacing all 65 teeth would be about 3000 Rupees. Keeping this in mind, replacing all 65 teeth twice a year would cost about 11500 Rupees, which is less than the total cost of the traditional gear design. In comparison to the conventional gear design, the proposed design reduces long-term maintenance costs.
Study of Defect Morphology and Density on Mechano-Electrochemical Effect of Pipeline Corrosion
Authors: Rashidi Sedigheh , Zandiatashbar Ardavan , Farhad Siamak
Published: January 2022

Steel pipeline in the oil and gas industry is subject to complex stress-strain due to soil movement along the pipes and internal pressure. The induced longitudinal strains due to soil movement along the pipe and the induced elasto-plastic local strain distribution are shown to impact the pipeline corrosion. In this work, we study the effect of defect geometry and density along the pipe on the local stress-strain distribution and subsequent local corrosion activity. Small strain von Mises yielding criteria is used and corrosion potential, anodic current density, and cathodic current density are characterized and used for this study by looking at the center to edge ratio.
A High-Order Spectral Difference Solver for 2D Ideal MHD Equations With Constrained Transport
Authors: Chen Kuangxu , Liang Chunlei
Published: January 2022

When using the discontinuous Galerkin or Spectral Difference (SD) method to discretize ideal magnetohydrodynamic (MHD) equations, it is challenging to satisfy the divergence-free constraint for the magnetic field over long-period time integration. To tackle this challenge, the SD method is integrated with an unstaggered Constrained Transport approach (SDCT). In addition to solving the two-dimensional ideal MHD equations, one more equation describing the transport of the magnetic potential is introduced. After each time step, the magnetic field will be updated by computing the curl of the magnetic potential. This strategy preserves ∇ · B = 0 exactly by construction in the discrete sense. Meanwhile, the additional computational cost is only approximately 20% more than that without the constrained transport. Moreover, the inclusion of the constrained transport does not obstruct the implementation of the artificial viscosity for shock capturing.

Several well-known benchmark test cases are studied in this paper using the SDCT method. In the magnetic field loop advection test, the proposed SDCT avoids spurious growth of magnetic energy, and the numerical dissipation is shown to decrease when increasing the polynomial degree while maintaining the total degrees of freedom. In the propagation of Alfvén wave problem, the high-order accuracies of the SDCT method are verified. In the Orzag-Tang vortex problem, the predicted pressure distribution and density contours match well with those in the reference [1]. Meanwhile, a mesh convergence study shows that the SDCT method equipped with the artificial viscosity terms can produce converged results even in the vicinity of shocks.
Development of a Topology Optimization Framework For Cooling Channel Design in Die Casting Molds
Authors: Navah Farshad , Lamarche-Gagnon Marc-Étienne , Ilinca Florin , Audet Martin , Molavi-Zarandi Marjan , Raymond Vincent
Published: January 2022

This work is concerned with the development of a framework for the efficient design of cooling channels via two different topology optimization paradigms: a diffuse and a sharp. Each approach relies on a distinct thermo-fluid modeling and features a specific material distribution mode, i.e. fraction-based (diffuse) versus interface-based (sharp). The two models are described and the corresponding solvers are validated. A gradient-based optimization methodology is adopted and the details of the adjoint-based gradient computation are introduced. Finally, examples of cooling channel design optimization are presented and discussed.
Biphasic Representative Elemental Volumes for 3-D White Matter Elastography
Authors: Wu Xuehai , Georgiadis John G. , Pelegri Assimina A.
Published: January 2022

White matter (WM) characterization is challenging due to its anisotropic and inhomogeneous microstructure that necessitates multiscale and multi-modality measurements. Shear elastography is one such modality that requires the accurate interpretation of 3D shear strain measurements, which hinge on developing appropriate constitutive tissue models. Finite element methods enable the development of such models by simulating the shear response of representative elemental volumes (REV). We have developed triphasic (axon, myelin, glia), 2D REVs to simulate the influence of the intrinsic viscoelastic property and volume fraction of each phase. This work constitutes the extension of 2D- to 3D-REVs, focusing on the effect of the intrinsic material properties and their 3D representation on the viscoelastic response of the tissue. By lumping the axon and myelin phases, a flexible 3D REV generation and analysis routine is then developed to allow for shear homogenization in both the axial and transverse directions. The 2D and 3D models agree on stress distribution and total deformation when 2D cross-sectional snapshots are compared. We also conclude that the ratio of transverse to axial transverse modulus is larger than one when axon fibers are stiffer than the glial phase.
Wave Energy Converter Design as a Point Absorber to Generate 1 kW in Arequipa, Peru
Authors: Herrera Alejandro E. , Adriazola Pascual H. , Bravo Héctor J.
Published: January 2022

Electric energy is a resource that allows social development and the improvement of the quality of life of the inhabitants in the cove “La ballenita”, Mollendo, coast of Arequipa, Peru, where the electrical energy of the main network is not available.

The energy demand is approximately 1 kWh, which will allow provide enough energy to improve the quality of life, as well as the use of communications and food preservation. The use of supplementary energy sources such as a conventional generator set is economically and environmentally unfeasible at the site. The objective of the present study was to demonstrate that this problem can be solved by taking advantage of the geographical conditions. Since the area in question is near the ocean where maritime conditions would allow to solve this problem using a wave energy converter designed with the Water Energy Column method.

Wave energy is a viable alternative, with an initial investment you will have access to almost free and self-sustainable energy sufficient for the required needs, to achieve this it must be proven that the maritime conditions are adequate. Wave energy represents 295,000 TWh worldwide, but it has been poorly developed.

The first stage of the research was to demonstrate that the tidal conditions are suitable for power generation, the marine weather forecast system based on BUOYWEATHER points (data which covers a large geographic area) was used to validate the information obtained from records of the area where a measuring equipment was designed and manufactured.

This measurement prototype was designed and built to measure the wave variables that would be the basis of the Water Energy Column method. Data from 2018 were used for the study, which allowed to determine the critical wave which is the basis of calculation in the Water Energy Column method.

The measurement results showed that it is possible to generate electrical energy using wave energy in the study area by the Water Energy Column method. The nominal power of the design is more than 1 kW, the capacity factor of the system obtained is 15.67% and the LCOE (levelized cost of energy) is $ 0.11 / kWh, which means a feasible price in the electricity market. This cost represents the investment and low maintenance of operation. According to the CONESA impact method this value for the study is 25, which suggests a low environmental impact with some additional recommendations.

The contribution of the research would allow reducing the growth of hydrocarbon consumption which represents 78.3% of energy use worldwide and is a fundamental cause of the planet’s environmental problems and prove that the development of techniques for the use of energy is an alternative necessary.
In-Situ Monitoring in Abrasive Water Jet Machining of Stacked Titanium (Ti6Al4V)-CFRP Through Time and Frequency Analysis of Acoustic Emission Signals
Authors: Pahuja Rishi , Ramulu M.
Published: January 2022

Hybrid metal-composite structures are widely used in aerospace industry but the machining challenges, especially at high cutting speeds, limit their employability due to higher production costs and tool wear. Abrasive Water jet (AWJ) is a viable high speed alternative, to conventional milling but the process is limited by the kerf roughness and striations, burrs and delamination. Due to difference in machining behavior of ductile metal and brittle composite, the resulting surface quality is sensitive to the use of non-optimal process parameters, and in-process faults and defects. This study explores the AWJ process monitoring in machining Ti6Al4V-CFRP stacks through Acoustic emission (AE) signals. AWJ Machining experiments were conducted with varying pressure (200, 275, 350 MPa) and traverse feed rate (15, 7.5, 10 mm/s) for two stacking configurations — Ti/CFRP and CFRP/Ti. AE signals acquired at each of these material layers were correlated with the process parameters. Signal RMS was calculated in time domain and a correlation was found with the jet power-to-speed ratio (Ė/u). Further, the AE signals were studied in frequency and simultaneous time-frequency domain. A characteristic frequency, based on an estimation of abrasive particle impacts, was calculated (222.5 kHz). This characteristic frequency band was used to monitor the surface quality. Among other features, maximum power spectral density (PSD) was found superior. Overall, a strong correlation was established between the Abrasive Water Jet process variables, AE signals and the resulting surface quality using the time-frequency spectrogram with the proposed characteristic frequency banding.