Mechanical Engineering Commons^™

A Robot-Assisted Acoustofluidic End Effector, Jan Durrer, Prajwal Agrawal, Ali Ozgul, Stephen C.F. Neuhauss, Nitesh Nama, Daniel Ahmed

Department of Mechanical and Materials Engineering: Faculty Publications

Liquid manipulation is the foundation of most laboratory processes. For macroscale liquid handling, both do-it-yourself and commercial robotic systems are available; however, for microscale, reagents are expensive and sample preparation is difficult. Over the last decade, lab-on-a-chip (LOC) systems have come to serve for microscale liquid manipulation; however, lacking automation andmulti-functionality. Despite their potential synergies, each has grown separately and no suitable interface yet exists to link macro-level robotics with micro-level LOC or microfluidic devices. Here, we present a robot-assisted acoustofluidic end effector (RAEE) system, comprising a robotic arm and an acoustofluidic end effector, that combines robotics and microfluidic functionalities.We …

Smooth Muscle Cells Affect Differential Nanoparticle Accumulation In Disturbed Blood Flow-Induced Murine Atherosclerosis, Hunter Miller, Morgan A. Schake, Badrul Alam Bony, Evan T. Curtis, Conner C. Gee, Ian Mccue, Thomas J. Ripperda Jr., Yiannis S. Chatzizisis, Forrest Kievit, Ryan M. Pedrigi

Department of Mechanical and Materials Engineering: Faculty Publications

Atherosclerosis is a lipid-driven chronic inflammatory disease that leads to the formation of plaques in the inner lining of arteries. Plaques form over a range of phenotypes, the most severe of which is vulnerable to rupture and causes most of the clinically significant events. In this study, we evaluated the efficacy of nanoparticles (NPs) to differentiate between two plaque phenotypes based on accumulation kinetics in a mouse model of atherosclerosis. This model uses a perivascular cuff to induce two regions of disturbed wall shear stress (WSS) on the inner lining of the instrumented artery, low (upstream) and multidirectional (downstream), which, …

Microfabricated Platforms To Investigate Cell Mechanical Properties, Amir M. Esfahani, Grayson Minnick, Jordan Rosenbohm, Haiwei Zhai, Xiaowei Jin, Bahareh Tajvidi Safa, Justin Brooks, Ruiguo Yang

Department of Mechanical and Materials Engineering: Faculty Publications

Mechanical stimulation has been imposed on living cells using several approaches. Most early investigations were conducted on groups of cells, utilizing techniques such as substrate deformation and flow-induced shear. To investigate the properties of cells individually, many conventional techniques were utilized, such as AFM, optical traps/optical tweezers, magnetic beads, and micropipette aspiration. In specific mechanical interrogations, microelectro- mechanical systems (MEMS) have been designed to probe single cells in different interrogation modes. To exert loads on the cells, these devices often comprise piezo-electric driven actuators that attach directly to the cell or move a structure on which cells are attached. Uniaxial …

Novel Peridynamic Models For Material Degradation And Mass Transport, Jiangming Zhao

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Fracture and corrosion are two major causes of structure failure. They can interact with each other, leading to faster material degradation. They are also under the influence of environmental conditions. The corrosion rate highly depends on the transportation rate of involving substances, while the fracture can be accelerated significantly due to fluid flow. These complex mechanisms involved in structure failure have troubled classical models for decades. The peridynamic (PD) theory introduced in 2000 has shown great potential in modeling such problems. In this work, we develop novel PD models for fracture, corrosion, mass transport, and viscous flow, which are building …

Quick - Release End Effector Tool Interface, Shane Farritor, Thomas Frederick

Department of Mechanical and Materials Engineering: Faculty Publications

The various embodiments herein relate to a coupling apparatus for a medical device having a coupler body, a cavity defined in the coupler body, a rotatable drive component disposed within the cavity and having at least two pin receiving openings, and an actuable locking ring disposed around the cavity.

Investigation Of The Prevalence Of Faults In The Heating, Ventilation, And Air-Conditioning Systems Of Commercial Buildings, Amir Ebrahimifakhar

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

This dissertation describes a large-scale investigation of heating, ventilation, and air-conditioning (HVAC) fault prevalence in commercial buildings in the United States. A multi-year dataset with 36,556 pieces of HVAC equipment including air handling units (AHUs), air terminal units (ATUs), and packaged rooftop units (RTUs) was analyzed to determine values for several HVAC fault prevalence metrics. The primary source of data for this study comes from three commercial fault detection and diagnostics (FDD) providers. Since each FDD provider uses different terms to refer to the same fault in an HVAC system, a mapping function was created for each FDD provider’s dataset, …

In Situ Characterization Of Tensile Behavior Of Laser Rapid Solidified Al–Si Heterogeneous Microstructures, Bingqiang Wei, Wenqian Wu, Dongyue Xie, Huai-Hsun Lien, Metin Kayitmazbatir, Amit Misra, Jian Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Heterogeneous Al–Si microstructure comprising of sub-micron-scale Al dendrites and nanoscale Al–Si fibrous eutectic was fabricated by processing as-cast Al-20wt.%Si alloy using laser rapid solidification. In situ tension tests explored high tensile strength ( ∼ 600 MPa) and ductility ( ∼ 10%) and high strain hardening rate ( ∼ 7 GPa). Microstructural characterization revealed the plastic co[1]deformation mechanisms between soft Al dendrites and hard nanoscale Al–Si eutectic. The progression of plasticity in nanoscale Al–Si eutectic with increasing applied strain is accommodated by dislocation plasticity in the nano-Al channels and cracking Si nanofibers. The propagation of nano-cracks is suppressed by surrounding Al, …

Digitally Twinned Additive Manufacturing: Detecting Flaws In Laser Powder Bed Fusion By Combining Thermal Simulations With In-Situmeltpool Sensor Data, R Yavari, A Riensche, E Tekerek, L Jacquemetton, H Halliday, M Vandever, A Tenequer, V Perumal, A Kontsos, Z Smoqi, K Cole, P Rao

Department of Mechanical and Materials Engineering: Faculty Publications

The goal of this research is the in-situ detection of flaw formation in metal parts made using the laser powder bed fusion (LPBF) additive manufacturing process. This is an important area of research, because, despite the considerable cost and time savings achieved, precision-driven industries, such as aerospace and biomedical, are reticent in using LPBF to make safety–critical parts due to tendency of the process to create flaws. Another emerging concern in LPBF, and additive manufacturing in general, is related to cyber security – malicious actors may tamper with the process or plant flaws inside a part to compromise its performance. …

Contact Angle Measurement Using A Hele-Shaw Cell: A Proof-Of-Concept Study, Haipeng Zhang, Jacob Gottberg, Sangjin Ryu

Department of Mechanical and Materials Engineering: Faculty Publications

Contact angle is an important property to quantify the wettability of a solid surface with a liquid, which characterizes interactions of the solid-liquid pair. Generally, to measure contact angle, special instruments such as a goniometer are necessary, but they are not readily available in certain research settings. In this study, an alternative method to measure contact angle based on a Hele-Shaw cell, microscopy imaging, and image processing is suggested. In this method, a liquid drop is injected into a transparent Hele-Shaw cell, the meniscus of the drop is captured in the top or bottom view using a brightfield microscope, and …

Contact Angle Measurement Using A Hele-Shaw Cell: A Proof-Of-Concept Study, Haipeng Zhang, Jacob Gottberg, Sangjin Ryu

Department of Mechanical and Materials Engineering: Faculty Publications

Contact angle is an important property to quantify the wettability of a solid surface with a liquid, which characterizes interactions of the solid-liquid pair. Generally, to measure contact angle, special instruments such as a goniometer are necessary, but they are not readily available in certain research settings. In this study, an alternative method to measure contact angle based on a Hele-Shaw cell, microscopy imaging, and image processing is suggested. In this method, a liquid drop is injected into a transparent Hele-Shaw cell, the meniscus of the drop is captured in the top or bottom view using a brightfield microscope, and …

A Single Cell Pair Mechanical Interrogation Platform To Study Cell–Cell Adhesion Mechanics, Amir Monemianesfahani

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Cell-cell adhesion complexes are macromolecular adhesive organelles that integrate cells into tissues. Perturbations of the cell-cell adhesion structure or relatedmechanotransduction pathways lead to pathological conditions such as skin and heart diseases, arthritis, and cancer. Mechanical stretching has been used to stimulate the mechanotransduction process originating from the cell-cell adhesion and cell-extracellular matrix (ECM) complexes. The current techniques, however, have limitations on their ability to measure the cell-cell adhesion force directly and quantitatively. These methods use a monolayer of cells, which makes it impossible to quantify the forces within a single cell-cell adhesion complex. Other methods using single cells or cell …

Toward An Understanding Of Fundamental Mechanisms In Transitional And Turbulence Flow Control, Ethan A. Davis

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Turbulence is an emergent phenomenon found throughout nature and engineering, alike. It plays a vital role in the aquatic locomotion of organisms, scalar mixing, fluid transport, shipping and transportation, and even the flow of biological fluids in the human body. Therefore, it is of utmost importance in both a practical and engineering sense to better understand turbulence with the goal of better controlling it. This dissertation focuses broadly on better understanding the underlying mechanisms behind wall-bounded turbulent flows, with an emphasis on exploiting those mechanisms for turbulence flow control.

We developed a numerical simulation to study the effect of slip …

Thermomechanical Modeling In Laser Powder Bed Fusion Additive Manufacturing Using Graph Theory: Application To Prediction Of Recoater Crash, Md Humaun Kobir

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This work pertains to the laser powder bed fusion (LPBF) additive manufacturing process. The objective of this thesis is to predict a frequently occurring type of thermal-induced process failure in LPBF called recoater crash. To ascertain the likelihood of a recoater crash before the part is printed, we develop and apply a computationally efficient thermomechanical modeling approach based on graph theory.

Despite its demonstrated ability to overcome the design and processing constraints of conventional subtractive and formative manufacturing, the production-level scaleup of LPBF is hindered by frequent build failures. For example, the part often deforms as it is being printed …

Development Of A Mash Tl-3 Compliant Parapet Mounted Fence, Luis Rodriguez Alvizo

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

When roadways pass over railway tracks, there is a risk that debris from the roadway or pedestrians may fall onto the tracks and interfere with railway operations. Because of this, state Departments of Transportation (DOTs) commonly install debris fences in conjunction with bridge rails over railway tracks. However, the safety performance of debris fence systems when impacted by an errant vehicle has not been demonstrated through full-scale crash testing. Thus, the objective of this research was to develop a new, parapet-mounted debris fence for the Iowa DOT according to safety performance guidelines included in the American Association of State Highway …

Methods , Systems , And Devices Relating To Surgical End Effectors, Shane M. Farritor, Thomas Frederick, Joe Bartels

Department of Mechanical and Materials Engineering: Faculty Publications

The embodiments disclosed herein relate to various medical device components , including components that can be incorporated into robotic and / or in vivo medical devices, and more specifically including end effectors that can be incorporated into such devices. Certain end effector embodiments include various vessel cautery devices that have rotational movement as well as cautery and cutting functions while maintaining a relatively compact structure. Other end effector embodiments include various end effector devices that have more than one end effector.

Reduced-Order Modeling Of Loosening In Bolted Joints And Dynamic Interactions Between Axially Aligned Threaded Joints, Sandro Aldana

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Maintaining effective preload in bolted joints is critical for ensuring long-term performance and safety throughout the operation of any assembled structure. The loosening of bolted joints has been studied since the Industrial Revolution, but modeling approaches have only emerged over the past three decades. Although existing approaches are capable of simulating or predicting loosening in a single joint consisting of a single bolt, they are too computationally expensive to be used to model loosening in large structures consisting of many bolts. The objective of this thesis is to construct and employ a reduced-order modeling (ROM) approach that treats the internal …

Thermal And Mechanical Analysis Of Bombyx Mori Silk Nanofibers, Justin Busnot

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This thesis presents a study on the thermomechanical properties of Bombyx Mori silk nanofibers. These nanofibers were obtained from silkworm cocoons which were degummed to separate the fibroin and the sericin, the two proteins that make up silk. The fibroin was then centrifuged to remove insoluble particles and stored and 4°C before the electrospinning process. A parametric study of the electrospinning process was carried out in order to identify the factors allowing to obtain optimal mechanical properties. The current as well as the flow rate applied, the diameter of the syringe, the distance separating the syringe from collector or even …

Robotic Surgical Devices , Systems , And Related Methods, Shane Farritor, Erik Mumm, Philip Chu, Nishant Kumar, Jason Dumpert, Yutaka Tsutano

Department of Mechanical and Materials Engineering: Faculty Publications

The embodiments disclosed herein relate to various medical device components, including components that can be incorporated into robotic and / or in vivo medical devices. Certain embodiments include various modular medical devices for in vivo medical procedures.

In Vivo Printing Of Growth Factor-Eluting Adhesive Scaffolds Improves Wound Healing, Kristo Nuutila, Mohamadmahdi Samandari, Yori Endo, Yuteng Zhang, Jacob Quint, Tannin A. Schmidt, Ali Tamayol, Indranil Sinha

Department of Mechanical and Materials Engineering: Faculty Publications

Acute and chronic wounds affect millions of people around the world, imposing a growing financial burden on patients and hospitals. Despite the application of current wound management strategies, the physiological healing process is disrupted in many cases, resulting in impaired wound healing. Therefore, more efficient and easy-to-use treatment modalities are needed. In this study, we demonstrate the benefit of in vivo printed, growth factor-eluting adhesive scaffolds for the treatment of full-thickness wounds in a porcine model. A custom-made handheld printer is implemented to finely print gelatin-methacryloyl (GelMA) hydrogel containing vascular endothelial growth factor (VEGF) into the wounds. In vitro and …

Control Of Change Of Phase Through Physical Surface Shaping, Troy Anderson, Sidy Ndao, Craig Zuhlke, Dennis Alexander, George Gogos

Department of Mechanical and Materials Engineering: Faculty Publications

A system embodiment includes , but is not limited to , a solid structure configure to contact each of a material in a liquid phase and a material in a vapor phase , the solid structure including a plurality of microstructures protruding at angles relative to a horizontal plane ; and a layer of nanoparticles positioned on the plurality of microstructures , the layer of nanoparticles having a composition that is at least one of a same material as the plurality of microstructures and an oxide of the same material as the plurality of microstructures , the plurality of microstructures …

Minimally Invasive Delivery Of 3d Shape Recoverable Constructs With Ordered Structures For Tissue Repair, Shixuan Chen, Mark Alan Carlson, Xiaowei Li, Aleem Siddique, Wuqiang Zhu, Jingwei Xie

Department of Mechanical and Materials Engineering: Faculty Publications

Minimally invasive procedures are becoming increasingly more common in surgery. However, the biomaterials capable of delivering biomimetic, three-dimensional (3D) functional tissues in a minimally invasive manner and exhibiting ordered structures after delivery are lacking. Herein, we reported the fabrication of gelatin methacryloyl (GelMA)-coated, 3D expanded nanofiber scaffolds and their potential applications in minimally invasive delivery of 3D functional tissue constructs with ordered structures and clinically appropriate sizes (4 cm × 2 cm × 1.5 mm). GelMA-coated, expanded 3D nanofiber scaffolds produced by combining electrospinning, gas-foaming expansion, hydrogel coating, and crosslinking are extremely shape recoverable after release of compressive strain, displaying …

Maize Tassel Detection From Uav Imagery Using Deep Learning, Aziza Alzadjali, Mohammed H. Alali, Arun Narenthiran Weeranampalayam Sivakumar, Jitender S. Deogun, Stephen Scott, James C. Schnable, Yeyin Shi

Department of Mechanical and Materials Engineering: Faculty Publications

The timing of flowering plays a critical role in determining the productivity of agricultural crops. If the crops flower too early, the crop would mature before the end of the growing season, losing the opportunity to capture and use large amounts of light energy. If the crops flower too late, the crop may be killed by the change of seasons before it is ready to harvest. Maize flowering is one of the most important periods where even small amounts of stress can significantly alter yield. In this work, we developed and compared two methods for automatic tassel detection based on …

Novel And Fast Peridynamic Models For Material Degradation And Failure, Siavash Jafarzadeh

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Fracture is one of the main mechanisms of structural failure. Corroded surfaces with chemically-induced damage are, notably, potential sites for crack initiation and propagation in metals, which can lead to catastrophic failure of structures. Despite some progress in simulating fracture and damage using classical models, realistic prediction of complex damage progression and failure has been out of reach for many decades. Peridynamics (PD), a nonlocal theory introduced in 2000, opened up new avenues in modeling material degradation and failure. Existing numerical methods used to discretize PD equations, however, are quite expensive as the PD nonlocal interactions make them unaffordable for …

Uavs For Vegetation Monitoring: Overview And Recent Scientific Contributions, Ana I. De Castro, Yeyin Shi, Joe Mari Maja, Jose M. Pena

Department of Mechanical and Materials Engineering: Faculty Publications

This paper reviewed a set of twenty-one original and innovative papers included in a special issue on UAVs for vegetation monitoring, which proposed new methods and techniques applied to diverse agricultural and forestry scenarios. Three general categories were considered: (1) sensors and vegetation indices used, (2) technological goals pursued, and (3) agroforestry applications. Some investigations focused on issues related to UAV flight operations, spatial resolution requirements, and computation and data analytics, while others studied the ability of UAVs for characterizing relevant vegetation features (mainly canopy cover and crop height) or for detecting different plant/crop stressors, such as nutrient content/deficiencies, water …

Three-Dimensional Shape Analysis Of Peripapillary Retinal Pigment Epithelium-Basement Membrane Layer Based On Oct Radial Images, Junfei Tong, Pengfei Dong, Sachin Kedar, Deepta Ghate, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

The peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) layer angle was recently proposed as a potential index for estimating intracranial pressure noninvasively. However, the ppRPE/BM layer angle, measured from the optical coherence tomography (OCT) scans, varied across the radial directions of the optic disc. This made the ppRPE/BM layer angle difficult to be utilized in its full potential. In this study, we developed a mathematical model to quantify the ppRPE/BM layer angles across radial scans in relation to the ppRPE/BM 3D morphology in terms of its 3D angle and scanning tilt angles. Results showed that the variations of the ppRPE/BM layer …

Mash 2016 Test Level 3 And Test Level 4 Evaluation Of Roadside Safety Barrier With Pedestrian Features, Miguel Angel Hinojosa Palacios

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The Minnesota Department of Transportation (MnDOT) desires to use a vehicle, bicycle, and pedestrian combination bridge railing system along pedestrian and bicycle bridge paths. The system was evaluated per MASH 2016.

In full-scale crash test no. MNPD-3, the system was evaluated according to MASH test designation no. 3-11. The 2014 Dodge Ram 1500 crew cab pickup truck impacted the system 71¼ in. upstream from the centerline of post no. 4 with a speed of 63.4 mph at an angle of 25.3 degrees. The combination railing system was found to meet the AASHTO MASH 2016 TL-3 impact safety criteria.

MnDOT uses …

On The Comparison Of Flow Physics Between Minimal And Extended Flow Units In Turbulent Channels, Ethan A. Davis, Siamak Mirfendereski, Jae Sung Park

Department of Mechanical and Materials Engineering: Faculty Publications

Direct numerical simulations were performed to study the effects of the domain size of a minimal flow unit (MFU) and its inherent periodic boundary conditions on flow physics of a turbulent channel flow in a range of 200 ≤ Re_τ ≤ 1000. This was accomplished by comparing turbulent statistics with those computed in sub-domains (SD) of extended domain simulations. The dimensions of the MFU and SD were matched, and SD dynamics were set to minimize artificial periodicities. Streamwise and spanwise dimensions of healthy MFUs were found to increase linearly with Reynolds number. It was also found that both MFU …

Device Development For Long-Term Systemic Oral Biologic Drug Delivery, Benjamin Wankum

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

A biologic drug is a drug that is produced by a living organism. Biologic drugs are used to treat various medical conditions such as arthritis, diabetes, or certain forms of cancers due to their high potency and high selectivity of action. Drawbacks of biologics include their poor stability in the gastrointestinal tract and their poor absorption. In effect, this gives the drugs very low bioavailability and short therapeutic half-lives. To combat these obstacles, current delivery methods include subcutaneous injections at home or intravenous or intramuscular injections in a medical facility.

The overall scientific goal of the research was to utilize …

Evaluation Of Flared Approach Guardrail Transitions And Mash 2270p Ram Vehicle Model Improvements, Ryan F. Bickhaus

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The objective of this research study was to use computer simulation to identify the critical flare rate for flaring approach guardrail transitions (AGTs) away from the primary roadway. AGTs installed with a flared configuration result in a length of need (LON) reduction as well as an increase in the clear zone area in front of the barrier, which would reduce both installation cost and crash frequency. The research focused on the determination of the maximum allowable flare rate that could safely be utilized with 31-in. (787-mm) tall thrie-beam AGTs without concrete curbs that utilize the Midwest Guardrail System (MGS) upstream …

Development Of An Intraperitoneal Catheter Placement Device For Use On The Battlefield, Riley Reynolds

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The objective of this project was to simplify peritoneal cavity access so an Airforce field medic can safely infuse oxygen microbubbles (OMBs) into the intraperitoneal space for the emergency treatment of hypoxia due to lung damage. To solve this problem, we created an intraperitoneal catheter placement device for use on the battlefield. The three common methods and some of the most common devices for peritoneal cavity access were reviewed. Injury frequencies for each of the three methods were analyzed. The results showed that each of the access techniques gives a similar rate of iatrogenic injury.

The battlefield conditions where the …