Other Mechanical Engineering Commons^™

Preperitoneal Insufflation Pressure Of The Abdominal Wall In A Porcine Model, Riley E. Reynolds, Benjamin Wankum, Sean J. Crimmins, Mark A. Carlson, Benjamin S. Terry

Department of Mechanical and Materials Engineering: Faculty Publications

Background Most complications and adverse events during laparoscopic surgery occur during initial entry into the peritoneal cavity. Among them, preperitoneal insufflation occurs when the insufflation needle is incorrectly placed, and the abdominal wall is insufflated. The objective of this study was to find a range for static pressure which is low enough to allow placement of a Veress needle into the peritoneal space without causing preperitoneal insufflation, yet high enough to separate abdominal viscera from the parietal peritoneum.

Methods A pressure test was performed on twelve fresh porcine carcasses to determine the minimum preperitoneal insufflation pressure and the minimum initial …

Hydraulic Vehicle Challenge, Jacob Steiner, David Kotovets, Evan Blitz, Luke Fetherston, Alex Colucy

Williams Honors College, Honors Research Projects

The target goal of this project is for a team of students to design a vehicle which is based on human power as the primary mover of the system and achieves vehicle propulsion through the required use of hydraulics and pneumatics. In summary, the rider will power a pump that will generate pressure in order to move the fluid that drives the motor. This will result in the powered rotation of the wheels. As there are many possible designs, naturally, this means that the final design for the vehicle will have specific limitations such as weight and the required use …

Entertainment 721, Mark Hendricks, Noah John, Jadon Vanyo, Chelsea Payne

Williams Honors College, Honors Research Projects

The goal of this project was to design a luxury, aesthetically pleasing entertainment system with a TV lift mechanism that could be remote controlled. The design would also include a cooling cabinet for gaming systems, a remote locking system, and additional storage. Using a morphological chart and weighted decision matrix for each subsystem key features were determined to be included in the design. Several performance benchmarks were determined to accomplish the team’s design. Almost every benchmark was successful in the build of the first prototype. Several heat calculations and FEA analyses were performed on the system to ensure the success …

4040c Universal Tester Backup, Devan Keeling, John Bowen, Cameron Bosner, Jacob Lenart

Williams Honors College, Honors Research Projects

The 40 Series valve is one of Swagelok's highest volume part families of which 60,000 parts per year shipped are multi-ported. The multiport configuration requires a unique tester to ensure proper assembly and quality of upstream processes.

Due to the multiport configuration of these valves no alternate testing option exists, resulting in a high rate of customer disappointments per day should the equipment fail.

In addition to the tester's criticality, it has also been ranked as one of Swagelok's most unhealthy assets and is probable to experience extended downtime in the future.

This project proposes to design and build a …

Torrefaction Of Mixed Solid Waste, Zhuo Xu

Dissertations, Master's Theses and Master's Reports

The world is witnessing unprecedented accumulation of solid wastes in the environment and landfills with well-documented ecological, environmental, health, and economic consequences. With population growth and rise in living standards, solid wastes generation will increase, making the issue more pressing. In addition, current practices of solid waste disposal are creating an immediate challenge and a long-term disaster-scale problem. The solid wastes comprises two main groups of materials: (i) fiber wastes (paper, food, wood, trimming, 61% of U.S. municipal solid waste) and (ii)uniquely challenging subset of plastic wastes (13%) that become a threat to global sustainability including dangers to marine and …

Nondestructive Evaluation Of Aluminium Foam Panels Subjected To Impact Loading, Gabriella Epasto, Fabio Distefano, Hozhabar Mozafari, Emanoil Linul, Vincenzo Crupi

Department of Mechanical and Materials Engineering: Faculty Publications

Aluminium foam sandwich structures have excellent energy absorption capacity, combined with good mechanical properties and low density. Some of the authors of this paper proposed an innovative Metallic Foam Shell protective device against flying ballast impact damage in railway axles. A closed-cell aluminium foam was chosen for the Metallic Foam Shell device. The main goal of this study was the experimental investigation of the impact responses of aluminium foam panels. Low velocity impact tests were carried out at different energies on different types of aluminium foam panels in order to investigate the effects of some parameters, such as core thickness, …

Surface Strengthening Of Single-Crystal Alumina By High-Temperature Laser Shock Peening, Fei Wang, X. L. Yan, Lei Liu, Michael Nastasi, Yongfeng Lu, Bai Cui

Department of Mechanical and Materials Engineering: Faculty Publications

This manuscript reports a novel process of high-temperature laser shock peening (HTLSP) for surface strengthening of single-crystal ceramics such as sapphire and reveals its fundamental mechanisms. HTLSP at 1200°C can induce a high compressive residual stress on the surface of sapphire while minimize the damage of laser-driven shock waves. Transmission electron microscopy characteriza- tions revealed high dislocation densities near the surface, suggesting that plastic deformation at an ultrahigh strain rate was generated by the high shock wave pressure. The HTLSP-induced compres- sive residual stress can significantly improve the hardness and fracture toughness of sapphire, while maintain its outstanding optical transmittance.

The Role Of Microenvironmental Cues And Mechanical Loading Milieus In Breast Cancer Cell Progression And Metastasis, Brandon D. Riehl, Eunju Kim, Tasneem Bouzid, Jung Yul Lim

Department of Mechanical and Materials Engineering: Faculty Publications

Cancer can disrupt the microenvironments and mechanical homeostatic actions in multiple scales from large tissue modification to altered cellular signaling pathway in mechanotransduction. In this review, we highlight recent progresses in breast cancer cell mechanobiology focusing on cell-microenvironment interaction and mechanical loading regulation of cells. First, the effects of microenvironmental cues on breast cancer cell progression and metastasis will be reviewed with respect to substrate stiffness, chemical/topographic substrate patterning, and 2D vs. 3D cultures. Then, the role of mechanical loading situations such as tensile stretch, compression, and flow-induced shear will be discussed in relation to breast cancer cell mechanobiology and …

Ligand Assisted Growth Of Perovskite Single Crystals With Low Defect Density, Ye Liu, Xiaopeng Zheng, Yanjun Fang, Ying Zhou, Zhenyi Ni, Xun Xiao, Shangshang Chen, Jinsong Huang

Department of Mechanical and Materials Engineering: Faculty Publications

A low defect density in metal halide perovskite single crystals is critical to achieve high performance optoelectronic devices. Here we show the reduction of defect density in per[1]ovskite single crystals grown by a ligand-assisted solution process with 3‐(decyldimethy[1]lammonio)‐propane‐sulfonate inner salt (DPSI) as an additive. DPSI ligands anchoring with lead ions on perovskite crystal surfaces not only suppress nucleation in solution, but also regulate the addition of proper ions to the growing surface, which greatly enhances the crystal quality. The grown CH₃NH₃PbI₃ crystals show better crystallinity and a 23-fold smaller trap density of 7 × 10 …

Social Connectedness And Negative Affect Uniquely Explain Individual Differences In Response To Emotional Ambiguity, Maital Neta, Rebecca L. Brock

Department of Mechanical and Materials Engineering: Faculty Publications

Negativity bias is not only central to mood and anxiety disorders, but can powerfully impact our decision-making across domains (e.g., financial, medical, social). This project builds on previous work examining negativity bias using dual-valence ambiguity. Specifically, although some facial expressions have a relatively clear negative (angry) or positive valence (happy), surprised expressions are interpreted negatively by some and positively by others, providing insight into one’s valence bias. Here, we examine putative sources of variability that distinguish individuals with a more negative versus positive valence bias using structural equation modeling. Our model reveals that one’s propensity toward negativity (operationalized as temperamental …

Direct Numerical Simulation Of A Pulsatile Flow In A Stenotic Channel Using Immersed Boundary Method, Siamak Mirfendereski, Jae Sung Park

Department of Mechanical and Materials Engineering: Faculty Publications

A three-dimensional direct numerical simulation model coupled with the immersed boundary method has been developed to simulate a pulsatile flow in a planar channel with single and double one-sided semicircular constrictions. For relevance to blood flow in large arteries, simulations have been performed at Reynolds numbers of 750 and 1000. Flow physics and resultant wall shear stress (WSS)-based hemodynamic parameters are presented. The instantaneous vortex dynamics, mean flow characteristics, and turbulent energy spectra are evaluated for flow physics. Subsequently, three WSS-based parameters, namely the time-averaged WSS, oscillatory shear index, and relative residence time, are calculated over the stenotic wall and …

Large-Scale Synthesis Of Compressible And Re-Expandable Three-Dimensional Nanofiber Matrices, Alec Mccarthy, Lorenzo Saldana, Daniel Mcgoldrick, Johnson V. John, Mitchell Kuss, Shixuan Chen, Bin Duan, Mark A. Carlson, Jingwei Xie

Department of Mechanical and Materials Engineering: Faculty Publications

Due to their biomimetic properties, electrospun nanofibers have shown great potential in many biomedical fields. However, traditionally-produced nanofibers are typically two-dimensional (2D) membranes limiting their applications. Herein, we report a large-scale synthesis of compressible and reexpandable three-dimensional (3D) nanofiber matrices for potential biomedical applications. The reproducible mass production of such matrices is achieved using a multiple-emitter electrospinning machine with a controlled environment (e.g., temperature, humidity, and air flow rate) followed by an innovative gas-foaming expansion. The modified 20-emitter circular array with 3D-printed needle caps is capable of maintaining stable Taylor cones under extremely high flow rates. The introduction of such …

Assembly Of Close-Packed Ferroelectric Polymer Nanowires Via Interface-Epitaxy With Res2, Dawei Li, Shuo Sun, Kun Wang, Zahra Ahmadi, Jeffrey E. Shield, Stephen Ducharme, Xia Hong

Department of Mechanical and Materials Engineering: Faculty Publications

The flexible, transparent, and low-weight nature of ferroelectric polymers makes them promising for wearable electronic and optical applications. To reach the full potential of the polarization-enabled device functionalities, large-scale fabrication of polymer thin films with well-controlled polar directions is called for, which remains a central challenge. The widely exploited Langmuir–Blodgett, spin-coating, and electrospinning methods only yield polymorphous or polycrystalline films, where the net polarization is compromised. Here, an easily scalable approach is reported to achieve poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) thin films composed of close-packed crystalline nanowires via interface-epitaxy with 1T′-ReS₂. Upon controlled thermal treatment, uniform P(VDF-TrFE) films restructure into …

Reducing Corrosion Of Additive Manufactured Magnesium Alloys By Interlayer Ultrasonic Peening, M. P. Sealy, R. Karunakaran, S. Ortgies, G. Madireddy, A. P. Malshe, K. P. Rajurkar

Department of Mechanical and Materials Engineering: Faculty Publications

Additive manufad (AM) magn alloys corrode rapidly due to tensile stress and coarse microstructures. Cyclically combining (hybridizing) additive manufacturing with interlayer ultrasonic peening was proposed as a solution to improve corrosion resistance of additive manufactured magnesium WE43 alloy through strengthening mechanisms and compressive residual stress. Applying interlayer peening work hardened discrete layers and formed a glocal integrity of regional grain refinement and subsurface compressive residual stress barriers. Tensile residual stress that typically accelerates corrosion decreased 90%. Results showed time-resolved control over corrosion was attainable by interlayer peening, and local corrosion within print cells decreased 57% with respect to as-printed WE43.

Ultra-Fast Charging In Aluminum-Ion Batteries: Electric Double Layers On Active Anode, Xuejing Shen, Tao Sun, Lei Yang, Alexey Krasnoslobodtsev, Renat F. Sabirianov, Michael P. Sealy, Wai-Ning Mei, Zhanjun Wu, Li Tan

Department of Mechanical and Materials Engineering: Faculty Publications

With the rapid iteration of portable electronics and electric vehicles, developing high-capacity batteries with ultra-fast charging capability has become a holy grail. Here we report rechargeable aluminum-ion batteries capable of reaching a high specific capacity of 200 mAh g^−1. When liquid metal is further used to lower the energy barrier from the anode, fastest charging rate of 10⁴ C (duration of 0.35 s to reach a full capacity) and 500% more specific capacity under high-rate conditions are achieved. Phase boundaries from the active anode are believed to encourage a high-flux charge transfer through the electric double layers. As …

Twinning-Assisted Dynamic Adjustment Of Grain Boundary Mobility, Qishan Huang, Qi Zhu, Yingbin Chen, Mingyu Gong, Jixue Li, Ze Zhang, Wei Yang, Jian Wang, Haofei Zhou, Jiangwei Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Grain boundary (GB) plasticity dominates the mechanical behaviours of nanocrystalline materials. Under mechanical loading, GB configuration and its local deformation geometry change dynamically with the deformation; the dynamic variation of GB deformability, however, remains largely elusive, especially regarding its relation with the frequently-observed GB-associated deformation twins in nanocrystalline materials. Attention here is focused on the GB dynamics in metallic nanocrystals, by means of well-designed in situ nanomechanical testing integrated with molecular dynamics simulations. GBs with low mobility are found to dynamically adjust their configurations and local deformation geometries via crystallographic twinning, which instantly changes the GB dynamics and enhances the …

Predictive Maintenance Of Bearing Machinery Using Simulation- A Bibliometric Study, Karan Gulati Mr., Keshav Basandrai Mr., Shubham Tiwari Mr., Pooja Kamat Prof., Satish Kumar Dr.

Library Philosophy and Practice (e-journal)

Modelling is a way of constructing a virtual representation of software and hardware that involves a real-world device. We will discover the behaviour of the system if the software elements of this model are guided by mathematical relationships. For testing conditions that may be difficult to replicate with hardware prototypes alone, modelling and simulation are particularly useful, especially in the early phase of the design process when hardware might not be available. Model-based approach in MATLAB-Simulink can be useful for predictive maintenance of machines as it can reduce unplanned downtimes and maintenance costs when industrial equipment breaks. Through this bibliometric …

Electron Microscopy Observation Of Electric Field-Assisted Sintering Of Stainless Steel Nanoparticles, Fei Wang, Qin Zhou, Xing-Zhong Li, Yongchul Yoo, Michael Nastasi, Bai Cui

Department of Mechanical and Materials Engineering: Faculty Publications

The intrinsic role of electrical current on the electric field-assisted sintering (EFAS) process of stainless steel 316L nanoparticles has been revealed by both ex situ and in situ experiments. A novel device on the Si chip has been designed and fabricated to fit into the sample holder of a transmission electron microscope for these experiments. The evolution of nanoparticle morphology and microstructures during the EFAS process has been studied using scanning electron microscopy and transmission electron microscopy, which has been combined with the simultaneous measurement of the electric voltage and current changes. A preliminary four-stage mechanism for the EFAS process …

On The Improvements Of Boundary-Layer Representation For High Resolution Weather Forecasting In Costal-Urban Environments, David Melecio-Vazquez

Dissertations and Theses

As large urban centers around the world become more densely populated, the global conversion from natural to man-made land surfaces will only increase. These land-use changes affect the urban surface energy budget which in turn changes the structure of the planetary boundary layer (PBL) above. With current high-performance computing systems, meteorological and built environment information can be better utilized to quantify the anthropogenic effects of these modifications. Although these systems have improved forecasting near-surface weather conditions, a comprehensive approach to represent urban impacts on the PBL is still limited. Improved PBL representation can lead to better weather and climate forecasts, …

The Diffuse Bounce Back Lattice Boltzmann Method And Its Applications On The Study Of Fluid-Particle Interactions, Geng Liu

Dissertations and Theses

Fluid-structure interaction is very broadly seen and widely used in many industrial, engineering and environmental processes. The lattice Boltzmann method has been preferred for simulating particulate flows due to its advantages of easy implementation, micro- and mesoscopic physical insights and parallel algorithm. Both sharp and diffuse boundary treatments are studied to recover curved and moving boundaries on structured orthogonal grids for the lattice Boltzmann method. These methods can describe curved boundaries more accurately and more smoothly than the naive staircase approximation. However, to improve the order of velocity accuracy and to reduce the fluctuation of force, either interpolation or additional …