bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Lateral Restraint on Thermocapillary Migration of Wetting Droplets
Authors: Srinivasa Sagar Kalichetty , Dwaraknath K. G. , Pattamatta Arvind , Sundararajan T. 
Published: January 2020

Abstract
The present study aims at studying the characteristics of thermocapillary migration with varying levels of lateral restraints. A temperature gradient is created by heating and cooling either side of the substrate. When a droplet is placed near hot side it spreads as thin film and migrates towards the cold side. The advancing end assumes the shape of a parabolic rim while the receding end stays as a thin film. It is observed that the droplet decelerates to attain a steady state velocity and undergoes slight acceleration near the cold end of the substrate. The observed velocity trend follows the temperature gradient on the substrate. The velocity increases with the droplet volume and substrate temperature gradient. The liquid viscosity is observed to have a diminishing effect on migration velocity. The effect of lateral spread confinement is studied by performing experimental trails on substrates with different widths. It is found that reducing the substrate width increases the migration velocity due to increased footprint resulting in larger thermocapillary force. The results observed in the present study highlights the importance of thermocapillary flows in many academic and industrial applications.
Design and Development of a Cost-Effective LIDAR System for Transportation
Authors: Wiklund Theodore , Heim Mark , Halberstadt Jaret , Duncan Michael , Mittman Deven , DeAgostino Thomas , Depcik Christopher 
Published: January 2020

Abstract
Light Imaging Detection and Ranging (LIDAR) cameras and Light Detecting and Ranging (LiDAR) rangefinders were initially implemented in the 1960s as a higher-resolution and increased capability alternative to radar. Since then, LIDAR and LiDAR (hereto called lidar) have expanded into applications in aerial geographical surveying and collision-detection systems for autonomous vehicles. Current commercial systems are relatively expensive and potentially oversized for noncommercial applications. Consequently, this deters their use on consumer products like bicycles, where lidar systems can enable safety advancements that are necessary to counter the rising numbers of hazards affecting riders. In addition, widespread usage of inexpensive lidar systems can facilitate a more complete picture of our transportation infrastructure by delivering information (e.g., pavement quality) suited for U.S. Department of Transportation Highway Performance Monitoring System (HPMS) reports. This will aid in the creation of a safer infrastructure by highlighting critical areas in need of improvement and repair.
As a result, this effort outlines the development of a compact and cost-effective lidar system. The constructed system includes the ability to generate a static image by collecting several hundred thousand distance signals measured by a lidar rangefinder. Since the rangefinder has no self-contained rotation or translation systems, an Arduino Mega 2560 v3 microcontroller operates a pair of stepper motors that adjusts its azimuthal angle and pitch. Coalescing these signals into an ASCII text file for viewing in MATLAB results in a reasonably accurate picture of the surroundings. While the current system takes 1–2 hours to complete a full sweep, it has the potential to provide sufficient accuracy for HPMS reports at a moderate expenditure: the entire system costs less than $300. Finally, upgrading to a more powerful microprocessor, implementing slip rings for enhanced electrical connectivity, and refining the code by including interpolation between points will enable faster point cloud generation while still maintaining an inexpensive device.
Parametric Data-Driven Reduced Order Models With State Consistence for Aeroelastic Analysis
Authors: Krolick William C. , Wang Yi , Pant Kapil 
Published: January 2020

Abstract
This paper presents a framework to develop data-driven parametric reduced order models (PROMs) for aeroelastic (AE) analysis of flexible vehicles within a broad flight envelop. It is based on the separate domain and mode shape perturbation method. The flight envelop is first partitioned by multiple grid points, on each of which an aerodynamic ROM (AeroROM) is constructed using system identification (SYSID) techniques to capture dependence of the generalized aerodynamic force on the generalized displacement using data generated by high-fidelity CFD simulation. Then AeroROMs not on the grid point are obtained by interpolating those at neighboring grid points. Two interpolation schemes, i.e., the output-based interpolation and coefficient interpolation are developed. The parametric AeroROM is then coupled with the mode-based structural ROMs to enable integrated AE analysis under various flight conditions. The state consistence enabled by different SYSID techniques and performance of both ROM interpolation methods are also investigated. For the first time, it is found that the autoregressive exogenous ROM allows state consistence and direct model coefficient interpolation. The ROMs exhibit excellent agreement with CFD simulations (&lt; 3% relative error) and orders of magnitudes speedup. The effort opens up new opportunities for parametric AE analysis and flight control design.
Nonlinearity of Enhanced Cell Structures Having Auxetic Material Properties
Authors: Yang Chulho , Chang Young Bae , Lee Dongchan 
Published: January 2020

Abstract
This research is aimed at proposing an enhanced re-entrant hexagonal structure and examining its auxetic behavior in compressive or tensile load conditions. An integrated experimental and finite element analysis (FEA) approach was used to investigate the behavior of the proposed structures in combination with polymeric materials (thermoplastic polyurethane (TPU) materials such as Ninjaflex® and Semiflex®). We focused on the effect of nonlinearity of the structure on the overall stiffness and shock-absorption performance of the body protection pads. FEA models were used to examine how the stiffness and Poisson’s ratio are affected by static load conditions and also how the dynamic loads are transmitted through the auxetic structure. The static FEA models were verified through experimental testing. Advanced additive manufacturing (3D printing) techniques such as Fused Deposition Modeling (FDM) were used to build fixtures and prototypes of the auxetic polymeric structures. Structural stiffness and Poisson’s ratio were examined not only in tensile loading condition but also in compression. Axial and lateral deformations were measured for given axial forces on the experimental model, and the measured values of Poisson’s ratio were compared with the computational results. It was shown that the enhanced re-entrant hexagonal structures had nonlinear behavior, which could be a useful property for developing body protection pads and stiffness-varying structures.
Study of Peripheral Milling of Magnesium Matrix Composite
Authors: Anandan Nishita , Ramulu M. 
Published: January 2020

Abstract
An experimental investigation on peripheral milling of magnesium composite AZ91 magnesium matrix with 15 vol.% SiC particles of a nominal 3–4 μm was performed to study the cutting forces generated, surface finish of the machined surface and the tool wear as a function of cutting conditions. The feed force was found to increase with feed and spindle speed, while the thrust forces were found to increase with feed and no significant trend was observed with the increase in spindle speed. The feed and spindle speed were varied from 0.2 to 1 mm/rev and 1000 to 4000 rpm respectively. The length of cut was kept constant at 32 mm.
The tool wear was measured along the helical cutting edge and the wear mechanism was studied through SEM images of the cutting edge. A tapered wear geometry was observed which can be attributed to the varying chip load along the helix. Abrasive wear was identified as the main wear mechanism. Micro-ploughing and micro-pitting were also observed. The extent of micro-ploughing and micro-pitting depended on the cutting condition. When the impact on the cutting edge was high during aggressive machining condition of 0.5 mm/rev and 4000 rpm, extensive micro-pitting and micro-ploughing were observed on the flute. The cutting edges appeared to be smooth due to repeated rubbing against SiC particles and wear debris.
Innovative Hole Making Process in Woven Composite Laminates
Authors: Jadhav Vishwas S. , Kelkar Ajit D. 
Published: January 2020

Abstract
This paper proposes an innovative hole making manufacturing method for the composite laminates. The laminates were fabricated using heated vacuum assisted resin transfer molding (HVARTM) technique using plain weave carbon fibers and epoxy resin. Plain weave carbon fabric laminae were stacked together, and five metal pins were inserted in dry fabric at specific distances without causing any damage to the carbon fiber strands. The stacked plies were then infused with epoxy resin to fabricate laminates, which were about 2.6 mm (0.1″) thick. The laminates were cured as per the manufacturer specifications and after curing metal pins were popped out from the laminate. This resulted in holes in the panels without any damage to the continuous carbon fiber strands. The fabricated laminates then were cut into open hole compression coupons using a water jet machine to obtain holes precisely at the center of the coupon. From the remaining panel, ten coupons were machined and half of them were drilled using traditional drilling machine and the remaining half were drilled by nontraditional water jet machining process. The coupons were then tested using ASTM D6484 method to study the mechanical properties of the laminates. The present method shows promising fabrication technique to create holes in the composite laminates without sacrificing the integrity of the continuous fibers.
An Analysis of the Aerodynamic Response of an Electroactive Membrane
Authors: Pulok Mohammad Khairul Habib , Sarker Pratik , Chakravarty Uttam K. 
Published: January 2020

Abstract
Dielectric elastomer membranes are a category of electroactive polymers composed of a thin elastomer film sandwiched between two compliant electrodes. An electrostatic pressure is created when there is an externally applied voltage on the electrodes which creates compression in the thickness direction and extension in the in-plane direction. This outlines a variation of the tension in the membrane that can be used to change its dynamic behavior. In this study, a specimen of an electroactive membrane, VHB 4910 is considered to observe the aerodynamic characteristics under external flow of air. Both experimental and numerical analyses are performed to predict the fluid-structure interaction behavior of the specimen for different angles of attack. A vibration testing arrangement is used to estimate the resonance frequencies and the mode shapes which are validated by the finite element results. From the study, the coefficient of lift is found to increase with the angle of attack up to a critical value. Similarly, the coefficient of drag increases with the angle of attack. Both lift and drag coefficients decrease with the Reynolds number. The magnitudes of the natural frequencies decrease as the applied voltages rise. The natural frequencies and mode shapes of the membrane can be tuned by changing the pretension, the pressure, and/or the voltage.
Fiber Creation and Deposition on Arbitrary Surfaces With Gas-Modified Electrospinning
Authors: Kooistra-Manning Emily A. , Huston Lane G. , Skinner Jack L. , Andriolo Jessica M. 
Published: January 2020

Abstract
Electrospinning (ES) is a manufacturing technique used for the fabrication of polymer-based nano to microscale fibers with a high surface-area-to-volume ratio. Traditional ES involves a large floor or tabletop apparatus and must include a collection substrate that is electrically charged relative to the spinneret. Here, we report a miniaturized electrospinner designed for efficiency and portability, which eliminates dependency on an electrically connected deposition surface through addition of gas flow. Using the portable system, polyethylene oxide (200k MW) fiber mats were deposited. During ES, air flow rate, separation distance, and applied voltage were varied, and resultant fiber mats were analyzed and compared for quality and dimension. Finite element analysis was used to predict fiber deposition coverage in conjunction with experimental parameters.
Mechanical Behavior of Collagen Mimetic Peptides Under Fraying Deformation via Molecular Dynamics
Authors: Rawal Atul , Rhinehardt Kristen L. , Mohan Ram V. 
Published: January 2020

Abstract
Collagen is a pervasive, triple helical, extracellular matrix (ECM) protein, found in human body from skin and bones to blood vessels and lungs, making it biocompatible, biodegradable, capable of cell attachment, and relevant for applications in bio-polymers, tissue engineering and a plethora of other bio-medical fields. Natural collagen’s extraction from natural sources is time consuming, sometimes costly, and it is difficult to render, and could present undesired biological and pathogenic changes. Nanoscale collagen mimetic peptides (Synthetic Collagen), without the unwanted biological entities present in the medium, has shown to mimic the unique properties that are present in natural collagen. Synthetic collagen, thus provides a superior alternative compared to natural collagen for its utilization in several applications. Their properties are affected by surrounding environments, including various solvents, and can be tailored toward specific applications. The focus of this paper is to investigate the mechanical properties of these nanoscale collagen mimetic peptides with lengths of about 10nm, leading to understanding of their feasibility in bio-printing of a composite polymeric collagen biomaterial with a blend of multiple synthetic collagen molecules. Molecular dynamics modeling is used to simulate, model and analyze mechanical properties of synthetic collagen peptides. In particular, mechanical behavior of these peptides are studied. An in-depth insight into the deformation and structural properties of the collagen peptides are of innovative significance for a multitude of bio medical engineering applications. Present paper employed steered molecular dynamics as the principal method of investigating the mechanical properties of nanoscale collagen mimetic peptide 1BKV, which closely resembles natural collagen with a shorter sequence length of 30 amino acids. A detailed comprehension of the protein’s mechanical properties is investigated through fraying deformation behavior studied. A calculated Gibbs free energy value of 40 Kcal/mol corresponds with a complete unfolding of a single alpha-helix peptide chain from a triple helical protein in case of fraying. Force needed for complete separation of the alpha-helix from the triple-helical protein is analyzed, and discussed in this paper.
Replicas Fabrication by Laser Scanner and Additive Manufacturing: A Preliminary Investigation
Authors: Rossoni Marco , Colombo Giorgio 
Published: January 2020

Abstract
This paper presents a preliminary investigation on the workflow that allows to replicate object by using 3D laser scanner and a desktop fused filament fabrication 3D printer. Pitfalls and limitations of those technologies will be pointed out in order to find the bottleneck of the workflow, paying specific attention to what concerns the digital workflow from the acquisition to the generation of the g-code. The findings and conclusions are drawn from a case study that has been carried out using the minimum amount of human intervention, especially during the digital postprocessing of the data. The objects under investigation is a broken car door handle. Firstly, it has been digitalized using a 3D laser scanner properly calibrated and set. The accuracy, precision and resolution of the measurement tool have been recorded and the as-is acquired data has been checked against topological errors. The as-is acquired model has been compared with the original geometry. The 3d polygonal mesh has been prepared for being printed: the material, machine and process parameters have been chosen. A simulation of the deposition process to estimate warps and deviation from the nominal geometry was carried out. Finally, the object has been additively manufactured using a desktop Fused Filament Fabrication machine: the printed object has been again compared with the original geometry.
Current Trends of Mechanical Engineering Undergraduate Curricula in California
Authors: Ngo Chean Chin , Oh Sang June 
Published: January 2020

Abstract
This paper reviews and compares 29 ABET accredited mechanical engineering undergraduate curricula in California which include 13 programs from the California State University (Cal State or CSU) System, 8 programs from the University of California (UC) System and 8 programs from private universities. The programs examined in the present paper include both Ph.D.-granting and non-Ph.D.-granting institutions in public and private universities. Some CSU mechanical engineering programs have been taking steps to implement changes recently in their curricula to reduce the total required degree requirement to 120 units and yet satisfy the minimum requirement of general education units. This paper presents a summary of the current curricula structure of these programs in Cal State universities by delving into the study of their degree requirements and compare with that of UC and private universities. For example, the number of units of college level mathematics and basic science required by the program is examined closely and determine if it is beyond the one-year requirement by ABET General Criterion 5 Curriculum. In addition, one of the ABET program criteria requires the mechanical engineering program to prepare students to work professionally in either thermal or mechanical systems. As such, this present paper also examines how each program is proportionately distributing courses in each of these two areas. Attention is also given to how each program integrates first year experience, senior capstone design experience, hands-on laboratory experience and internship experience (if any) in the curriculum. In January 2016, CSU launched the Graduation Initiative (GI) 2025 to increase graduation rates of CSU students while eliminating opportunity gap for underrepresented minorities and Pell-eligible students. One of the main goals of GI 2025 is to increase the freshman 4-year graduation rate of CSU students to 40% by 2025. Part of the strategies for GI 2025 from some CSU campuses is to review the curriculum and identify potential barriers to timely graduation and find strategies to eliminate them. The goal of this paper is to provide educators a timely summary of reference while examining their own curricula. Although different institutions carry curricular revisions that stem from different motivation, the ultimate goal will be the same — provide students optimally the best curriculum to better prepare them for the industry workforce and have positive impact for the society.
Dynamic Behaviour of a Dacron Aortic Graft
Authors: Tubaldi Eleonora , Ferrari Giovanni , Balasubramanian Prabakaran , Amabili Marco 
Published: January 2020

Abstract
Woven Dacron grafts are still considered the clinical standard practice in thoracic vascular reconstruction in the case of aortic aneurysm and acute dissection. Despite its characteristics of biocompatibility and durability, very little is known about the dynamic response of Dacron grafts and about their side effects on the heart workload and cardiovascular system. In this study, physiological blood flow conditions are imposed in a Dacron graft via a specifically-developed mock circulatory loop. The effects of different physiological pulsation-per-minute rates are investigated. Since the Dacron prosthesis is extremely stiffer circumferentially and compliant axially with respect to an aortic segment of the same length, bending oscillations are preferred by the graft. This leads to a very significant different dynamic behavior with respect to the replaced human aortic portion altering cardiovascular pressure and blood flow dynamics and eventually causing long-term implant complications.
Numerical Study of the Percussive Riveting Process: Initial Results
Authors: Krovvidi Sai C. , Ramulu M. , Reinhall Per G. 
Published: January 2020

Abstract
Percussive riveting is a dependable assembly method that produces high-quality joints in the aerospace industry. Its successful application is derived from its ease to implement in an assembly floor environment. The rivets are formed on the shank end of the rivet using a forming tool like a bucking bar and the head is constrained and impacted with a rapid succession of hits using a pneumatic gun with a special purpose die head. The rivet forms an interference fit joint because of the residual compressive stresses that are set up in the circumferential direction due to plastic flow of rivet material. These compressive stresses are balanced by tensile stresses in the skin and stiffener bulk material. Compressive stresses in the longitudinal direction help keep the skins pressed together. Research studies focused on the dynamics modeling of the percussive riveting process for robotic automation have not delivered an understanding of the temporal evolution of stress and strain fields in the vicinity of the rivet and the rivet hole. These studies aimed to produce joints of equal strength using automated assembly process compared with the manual assembly process. No modeling efforts have been published up to this point in time. This understanding is important in order to produce joints of predictable strength. A simulation effort for an unstiffened percussive riveting stackup assembly will be undertaken to study the trends of beneficial compressive residual stresses and strains within the bucked rivet. It is our goal to eventually estimate joint strength for prescribed sets of joint assembly parameters. The domain of interest will be restricted to few inches from the rivet axis.
Printability of Hydrogels for Hydrogel Molding Based Microfluidic Device Fabrication
Authors: Vicente Adam , McCreery Zachary , Yan Karen Chang 
Published: January 2020

Abstract
Microfabrication-free methods have been developed in recent years for fabricating microfluidic devices to enable the applications of microfluidic devices to a broader range. Our group has been working on developing a process for fabricating electrospun fiber embedded microfluidic devices by integrating hydrogel molding (HGM) and electrospinning (ES), and the feasibility of this integrated method has been demonstrated through our initial study. Recently, we have modified an extrusion based 3D printer kit to deposit hydrogels and form microchannels. Agarose has been used for our previous studies owning to its temperature dependent gelation.
In this study, we examined the feasibility of using gelatin gel as an alternative material for hydrogel molding. Gel materials with various concentrations were examined via printability assessments; and optimal gel materials were identified. Upon completion of pattern printing, the samples were then encapsulated in polydimethylsiloxane (PDMS) and cured; formed microchannels were then characterized via micrographic image analysis. The results show that three gels, 2% w/v agarose gel, 7.5% w/v gelatin gel, and a mixture of 2% w/v agarose gel and 7.5% w/v gelatin gel (1:1 ratio), yield consistent printed patterns and form consistent microchannels subsequently.