Mechanical Engineering Commons^™

Three-Dimensional Printing Of Calcium Phosphate-Mesoporous Bioactive Glass Scaffolds For Bone Tissue Engineering, Ana Beatriz Gomes De Carvalho, Lais Medeiros Cardoso, Igor Paulino Mendes Soares, Joyce Rodrigues De Souza, Arpita Roy, Prabaha Sikder, Et. Al.

Mechanical Engineering Faculty Publications

Calcium phosphate cements (CPCs) and biomaterials, such as mesoporous bioactive glass (MBG), are critical for bone tissue engineering. This study aimed to 3D-print CPC scaffolds modified with MBG to enhance their osteogenic potential and regenerative ability. MBG powder was synthesized and characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and nitrogen adsorption-desorption techniques. A commercial CPC ink (hydroxyapatite/alpha-tricalcium phosphate) was mixed with 5% MBG (w/w; CPC/MBG), and, after rheological assessment, the mixture was used to obtain scaffolds via 3D printing. These scaffolds were then tested for chemical, morphological, and mechanical properties, as well as ion release analysis. Unmodified CPC …

A Review Of Waste Heat Sources For District Heating, Olamide Opadokun, Yong Tao, Julian Lamb

Mechanical Engineering Faculty Publications

As the world's energy needs rise, carbon emissions and climate change become a bigger concern. Therefore, there is a growing need for cleaner energy sources as well as higher levels of energy efficiency. Building energy is of great interest to researchers and policymakers, as it accounts for about a third of global energy consumption, and this is projected to rise as more people gain access to higher incomes and improved amenities. For over a century, district energy systems have proved to be an efficient means of providing thermal energy to buildings, and developments in district heating have enabled the use …

A Magnesium Alloy With High Corrosion Resistance, Hardness And Elastic Modulus Enabled By Elemental Synergy, Alexander Helmer, Manoj V. Mugale, Tushar Borkar, Rajeev K. Gupta

Mechanical Engineering Faculty Publications

A magnesium alloy containing Ca, Ti, Zn, and In was synthesized via high-energy ball milling of elemental powders followed by spark plasma sintering. X-ray diffraction and scanning electron microscopy revealed a homogeneous matrix with dispersed Mg-rich phases and intermetallics. Potentiodynamic polarization tests revealed low corrosion current density (9.6 f 2.1 mu A/cm2), a noble corrosion potential (-1197 f 4 mVSCE), and a clear passive region, indicating excellent corrosion resistance. Nanoindentation tests showed high hardness (2.61 f 0.21 GPa) and elastic modulus (55.35 f 5.47 GPa), exceeding those of commercial Mg alloys.

Microstructural Evolution And Magnetic Properties Of Spark Plasma Sintered Smco5 And Smco5-Fe Composites, Farhan Ishrak, Michael Lastovich, Fu-Yun Tsai, Charles Perkins Iv, Henri Baldino, Alex Helmer, Sean Rego, Sanoj Karki, Daniel Hedlund, Rajeev Gupta, Tushar Borkar

Mechanical Engineering Faculty Publications

Optimizing SmCo(5-)based nanocomposites for high-temperature magnetic applications requires balancing coercivity and saturation magnetization, properties often compromised by grain coarsening, oxidation, and secondary phase formation during conventional sintering. This study investigates the microstructural evolution and magnetic properties of SmCo5 and SmCo5-Fe composites processed via high-energy ball milling followed by spark plasma sintering at 900 degrees C and 1000 degrees C, a route designed to retain the nanostructure while enabling rapid densification compared to conventional sintering. A suite of characterization techniques, including electron microscopy, X-ray diffraction, magnetometry, Magneto-optical Kerr effect, and magnetic force microscopy, reveals the extent of consolidation, phase composition, and …

Underwater Acoustic Integrated Sensing And Communication: A Spatio-Temporal Freshness For Intelligent Resource Prioritization, Ananya Hazarika, Mehdi Rahmati

Electrical and Computer Engineering Faculty Publications

Underwater acoustic communication faces significant challenges including limited bandwidth, high propagation delays, severe multipath fading, and stringent energy constraints. While integrated sensing and communication (ISAC) has shown promise in radio frequency systems, its adaptation to underwater environments remains challenging due to the unique acoustic channel characteristics and the inadequacy of traditional delay-based performance metrics that fail to capture the spatio-temporal value of information in dynamic underwater scenarios. This paper presents a comprehensive underwater ISAC framework centered on a novel Spatio-Temporal Information-Theoretic Freshness metric that fundamentally transforms resource allocation from delay minimization to value maximization. Unlike conventional approaches that treat all …

Effect Of Graphene Nanoplatelets Fraction On The Microstructure And Mechanical Properties Of Inconel 718 Composites Prepared By Spark Plasma Sintering, Sanoj Karki, Manoj Mugale, Satyavan Digole, Amit Choudhari, Mayank Garg, Caleb Schenck, Fu-Yun Tsai, Bharat Gwalani, Tushar Borkar

Mechanical Engineering Faculty Publications

Nickel-based superalloy, particularly Inconel 718, is a promising candidate in advanced structural and high-temperature applications, including turbine blades, combustors, and turbochargers. However, high-efficiency energy systems such as jet engines and land-based gas turbines demand increasingly high strength for advanced structural applications. Therefore, significant efforts are underway to enhance the strength of these materials. Reinforcement of graphene nanoplatelet (GNP), owing to its exceptional mechanical strength, lightweight, high aspect ratio, and high level of coherency with metal matrix, has been proposed as an effective way of incorporating high strength into the existing Inconel 718. In addition, the spark plasma-assisted heating process is …

Recent Advances In Modelling Of Frost Formation For Mechanical Systems, Yong Tao

Mechanical Engineering Faculty Publications

The physics underlying frost and ice formation has been extensively studied over the past few decades, with significant contributions to our understanding of this phenomenon. These insights have primarily been applied to engineering systems with refrigerated surfaces, such as refrigerators, freezers and heat pumps of various sizes. Despite considerable progress, the dynamic and complex mechanisms governing frost and ice formation remain an active area of research, as competing factors continue to challenge predictive accuracy. The increasing interest from stakeholders in reducing energy consumption and carbon footprints in mechanical systems further underscores the importance of advancing modelling and simulation capabilities in …

Corrosion Behavior Of Mgtizn And Mg4tizn Alloys After Ball Milling And Subsequent Spark Plasma Sintering, Alexander Helmer, Rahul Agrawal, Manoj Mugale, Tushar Borkar, Rajeev Gupta

Mechanical Engineering Faculty Publications

Magnesium-containing multi-principal element alloys (MPEAs) are promising for lightweight applications due to their low density, high specific strength, and biocompatibility. This study examines two Mg-Ti-Zn alloy compositions, equal molar MgTiZn (TZ) and Mg4TiZn (4TZ), synthesized via ball milling followed by spark plasma sintering, focusing on their microstructures and corrosion behaviors. X-ray diffraction and transmission electron microscopy revealed the formation of intermetallic phases, including Ti2Zn and Mg21Zn25 in TZ, while 4TZ exhibited a predominantly Mg-rich phase. Potentiodynamic polarization and immersion tests in 0.1 M NaCl solution showed that both alloys had good corrosion resistance, with values of 3.65 +/- 0.65 mu …

Ultrasonic Cavitation Erosion Behaviour Of Plastically Deformed Textured Stainless-Steel Surface, Amit Raturi, Mayank Garg, Harpreet S. Grewall, Harpreet S. Arora

Mechanical Engineering Faculty Publications

In this study, we utilized an innovative pathway to obtain exceptional resistance to the cavitation erosion-corrosion behavior by combining surface texturing with severe surface deformation. Severe surface deformation was carried out using stationary friction process (SFP) followed by micro-texturing through a micro-imprinting approach. The textured sample after processing (SFP+T) had erosion resistance that was 6-7 times greater than that of the as-cast sample under ultrasonic cavitation conditions. In addition, the SFP+T sample was able to sustain a similar trend in the erosion-corrosion medium as well. Furthermore, the flow field characteristics of textured and nontextured samples were investigated using numerical calculations …

Personalized Bioceramic Grafts For Craniomaxillofacial Bone Regeneration, Ana Beatriz G. De Carvalho, Maedeh Rahimnejad, Rodrigo L. M. S. Oliveira, Prabaha Sikder, Guilherme S. F. A. Saavedra, Et. Al.

Mechanical Engineering Faculty Publications

The reconstruction of craniomaxillofacial bone defects remains clinically challenging. To date, autogenous grafts are considered the gold standard but present critical drawbacks. These shortcomings have driven recent research on craniomaxillofacial bone reconstruction to focus on synthetic grafts with distinct materials and fabrication techniques. Among the various fabrication methods, additive manufacturing (AM) has shown significant clinical potential. AM technologies build three-dimensional (3D) objects with personalized geometry customizable from a computer-aided design. These layer-by-layer 3D biomaterial structures can support bone formation by guiding cell migration/proliferation, osteogenesis, and angiogenesis. Additionally, these structures can be engineered to degrade concomitantly with the new bone tissue …

4d Printing Of Pla And Pla-Based Composites For Load-Bearing Applications, Phaniteja Nagaraju

ETD Archive

This research investigates the deformation recovery of 3D-printed Polylactic Acid (PLA) shape memory polymers (SMPs). The study delves into the influence of Fused Deposition Modelling (FDM) parameters, such as nozzle temperature, layer thickness, and printing speed, on the thermomechanical behavior of PLA SMP honeycomb structures. The research identifies optimal printing conditions using the Taguchi approach and explores the cyclic shape memory recovery behavior of the optimized PLA SMP under compression loads.

Additionally, the research includes a chapter on the extrusion and printing of uniform-diameter polylactic acid carbon fiber (CFR-PLA) composite filaments. The synthesis of CFR-PLA involves planetary ball milling for …

Machine Learning Based Average Pressure Coefficient Prediction For Isolated High-Rise Buildings, Shiva Sai Reddy Marapakala

ETD Archive

In structural design, the distribution of wind-induced pressure exerted on structures is crucial. The pressure distribution for a particular building is often determined by scale model tests in boundary layer wind tunnels (BLWTs). For all combinations of interesting building shapes and wind factors, experiments with BLWTs must be done. Resource or physical testing restrictions may limit the acquisition of needed data because this procedure might be time-and resource-intensive. Finding a trustworthy method to cyber-enhance data-collecting operations in BLWTs is therefore sought.

This research analyzes how machine learning approaches may improve traditional BLWT modeling to increase the information obtained from tests …

Extrusion Of Uniform-Diameter Polyetheretherketone-Magnesium Phosphate Bio-Composite Filaments For 3d Printing Of Design-Specific Multi-Functional Implants, Vijay K. Bokam, Surendrasingh Y. Sonaye, Phaniteja Nagaraju, Harsha P.S. Naganaboyina, Prabaha Sikder

Mechanical Engineering Faculty Publications

Polyetheretherketone (PEEK) is a high-performance polymer material for developing implants for orthopedic, spinal, cranial, maxillofacial, and dentistry applications. However, the major limitation of PEEK implants is their bioinertness, i.e., their incapability to integrate with tissues. Therefore, prior efforts have always focused on developing hydroxyapatite (HA) coatings on PEEK or PEEK-HA composites. However, in this study, we engineered a highly novel bioceramic known as amorphous magnesium phosphate (AMP), which surpasses the bioactivity and biodegradation kinetics of HA. Subsequently, we incorporated AMP in PEEK to develop a unique PEEK-AMP bioactive composite in the form of uniform-diameter filaments, such that it can be …

Introduction To Data-Driven Systems For Plastics And Composites Manufacturing, Saeed Farahani, Srikanth Pilla, Yun Zhang, Fausto Tucci

Mechanical Engineering Faculty Publications

Applications of high-performance plastics and composites have widely been expanded to various industries due to their superior properties, such as high strength-to-weight ratio, chemical resistance, and thermal/electrical insulation. However, the numerous possible combinations of polymers and reinforcements/fillers, the variability of these materials, and their complex manufacturing processes pose challenges in terms of efficiently developing new plastics and composites, accurately modeling their properties, and effectively monitoring and controlling their manufacturing processes. Integrating data-driven techniques, such as machine learning, artificial intelligence, and big data analytics, is a promising pathway to overcome these challenges as it is demonstrated by the state-of-the-art research works …

Compounding And Melt Blending/Extrusion Of Polyether Ether Ketone (Peek) And Amorphous Magnesium Phosphate (Amp) For Fused Deposition Modelling (Fdm) Based 3d Printing, Vijay Kumar Bokam

ETD Archive

Polyether ether ketone (PEEK) is a high-performance polymer material for developing implants for orthopedic, spinal, cranial, maxillofacial, and dentistry applications. However, the major limitation of PEEK implants is their bio-inertness, i.e., their incapability to integrate with tissues. Therefore, prior efforts have always focused on developing Hydroxyapatite (HA) coatings on PEEK or PEEK-HA composites or sulfonation of PEEK surface or plasma treatment. As opposed, in this study, we engineered a highly novel bio-ceramic known as amorphous magnesium phosphate (AMP), which surpasses the bioactivity and biodegradation kinetics of HA. In this study, we employed High energy planetary ball milling, a mechanical alloying …

Evaporation And Condensation From Epiphytes During Saturated Conditions In A Maritime Live-Oak Forest (Georgia, Usa)., Akosh Raffai

ETD Archive

Most of the rain that falls over land, falls over forests, which cover approximately one-third of global land surface. Significant immediate and wide-ranging impacts are exerted on hydrological, ecological, and societal systems due to canopyrainfall interactions, altering rainwater supply to the surface. All storm-related hydrological processes are impacted by the relative rates that canopy surfaces retain, evaporate, and redistribute rain. Many forest canopies host a community of plants called epiphytes that are generally capable of storing and evaporating substantial water. Epiphytes are comparatively under-researched regarding their role in rainfall partitioning compared to bark and leaves. Skidaway Island in Savannah, Georgia, …

In-House Processing Of Carbon Fiber Reinforced Polyetheretherketone (Cfr-Peek) 3d Printable Filaments And Fused Filament Fabrication Of Cfr-Peek Parts, Harsha Phanindra Sai Naganboyina

ETD Archive

PEEK is a high-performance polymer known for its exceptional mechanical properties, making it suitable for various applications; however, for certain demanding applications such as automotive, PEEK does not exhibit the required strength. Moreover, if the PEEK parts are developed by Fused Filament Fabrication (FFF)-based 3D Printing, there is a high chance of having PEEK parts with decreased mechanical properties. Carbon Fiber (CF) reinforcement is a well-known method of mitigating the low mechanical properties of PEEK. Hence, in the present study, we attempted to develop CF-reinforced PEEK (CFR-PEEK) parts via FFF. First, we developed homogeneous CFR-PEEK mixtures via ball milling and …

Hybrid Fes-Exoskeleton Control: Using Mpc To Distribute Actuation For Elbow And Wrist Movements, Nathan Dunkelberger, Jeffrey Berning, Eric M. Schearer, Marcia K. O'Malley

Mechanical Engineering Faculty Publications

Introduction: Individuals who have suffered a cervical spinal cord injury prioritize the recovery of upper limb function for completing activities of daily living. Hybrid FES-exoskeleton systems have the potential to assist this population by providing a portable, powered, and wearable device; however, realization of this combination of technologies has been challenging. In particular, it has been difficult to show generalizability across motions, and to define optimal distribution of actuation, given the complex nature of the combined dynamic system. Methods: In this paper, we present a hybrid controller using a model predictive control (MPC) formulation that combines the actuation of both …

Coaxial Jets With Disparate Viscosity: Mixing And Laminarization Characteristics, Mustafa Usta, M. R. C. Ahmad, G. Pathikonda, I. Khan, P. Gillis, D. Ranjan, C. K. Aidun

Mechanical Engineering Faculty Publications

Mixing of fluids in a coaxial jet is studied under four distinct viscosity ratios, m = 1, 10, 20 and 40, using highly resolved large-eddy simulations (LES), particle image velocimetry and planar laser-induced fluorescence. The accuracy of predictions is tested against data obtained by the simultaneous experimental measurements of velocity and concentration fields. For the highest and lowest viscosity ratios, standard RANS models with unclosed terms pertaining to viscosity variations are employed. We show that the standard Reynolds-averaged Navier-Stokes (RANS) approach with no explicit modelling for variable-viscosity terms is not applicable whereas dynamic LES models provide high-quality agreement with the …

Data-Driven Dynamic Motion Planning For Practical Fes-Controlled Reaching Motions In Spinal Cord Injury, Derek N.N. Wolf, Antonie J. Van Den Bogert, Eric M. Schearer

Mechanical Engineering Faculty Publications

Functional electrical stimulation (FES) is a promising technology for restoring reaching motions to individuals with upper-limb paralysis caused by a spinal cord injury (SCI). However, the limited muscle capabilities of an individual with SCI have made achieving FES-driven reaching difficult. We developed a novel trajectory optimization method that used experimentally measured muscle capability data to find feasible reaching trajectories. In a simulation based on a real-life individual with SCI, we compared our method to attempting to follow naive direct-to-target paths. We tested our trajectory planner with three control structures that are commonly used in applied FES: feedback, feedforward-feedback, and model …

Predictions Of Indentation Stiffness Of Musculoskeletal Regions Using Ultrasound, Sean Doherty

ETD Archive

Tissue indentation response is an important metric for understanding how different musculoskeletal regions respond to loading and is a function of the tissue’s form. Modem imaging techniques provide information about the internal structures of human tissue. Ultrasound remains one of the most common imaging techniques performed, given its portability and low costs. Prior work and data collection on 100 patients involved the collection of ultrasound images at eight different locations across the musculoskeletal extremities. Given the tissue structure information that the medical imaging provided, it was hypothesized that the mechanical properties of the tissue could be predicted from this data. …

Strengthening Effects Of Carbon Nanotubes And Graphene Nanoplatelets Reinforced Nickel Metal Matrix Composites, Amit Patil

ETD Archive

Carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) with superior mechanical, thermal, chemical, and electrical properties are appealing reinforcements for the fabrication of lightweight, high-strength, and wear-resistant metal matrix composites with outstanding mechanical and tribological performance. The nickel-carbon nanotube composites (Ni-CNT) and nickel-graphene nano-platelet composites (Ni-GNP) were processed using two separate ball milling methods, namely dry ball milling (DM) and solution ball milling (SBM), and then sintered using the spark plasma sintering (SPS) technique. The influence of the premixing process, milling time, reinforcement morphology, and concentration on matrix grain size, microstructure, dispersion in the nickel matrix, mechanical properties, and tribological performance …

Development And Control Of A Pediatric Lower Limb Exoskeleton For Gait Guidance, Anthony Clarence Goo

ETD Archive

Several genetic, developmental and neurological disorders can cause various levels of gait impairment in the pediatric population. Powered lower limb orthoses, or exoskeletons, have recently been used to address gait impairment and afford therapists alternative solutions and strategies for gait therapy. Most exoskeleton research has focused on the adult population while the pediatric population remains underserved. The limitations of current pediatric exoskeletons make them impractical for use in both community and clinical settings. Furthermore, exoskeleton controllers suitable for these environments should promote human volitional control while guiding the subject towards a dynamically stable healthy gait pattern.

This dissertation presents the …

3d-Printed Piezoelectric Porous Bioactive Scaffolds And Clinical Ultrasonic Stimulation Can Help In Enhanced Bone Regeneration, Prabaha Sikder, Phaniteja Nagaraju, Harsha P.S. Naganaboyina

Mechanical Engineering Faculty Publications

This paper presents a comprehensive effort to develop and analyze first-of-its-kind design-specific and bioactive piezoelectric scaffolds for treating orthopedic defects. The study has three major highlights. First, this is one of the first studies that utilize extrusion-based 3D printing to develop design-specific macroporous piezoelectric scaffolds for treating bone defects. The scaffolds with controlled pore size and architecture were synthesized based on unique composite formulations containing polycaprolactone (PCL) and micron-sized barium titanate (BaTiO3) particles. Second, the bioactive PCL-BaTiO3 piezoelectric composite formulations were explicitly developed in the form of uniform diameter filaments, which served as feedstock material for the fused filament fabrication …

Mechanistic Understanding Of Phase Stability, Transformation, And Strengthening Mechanisms In Lightweight High Entropy Alloys And High Entropy Ceramics, Ganesh Walunj

ETD Archive

High-entropy alloys (HEAs) are a novel family of solid-solution alloys that have gained international interest due to their exceptional characteristics. Because of the need from the transportation and defense sectors, lightweight HEAs have attracted researcher’s curiosity as prospective advanced materials. Low-weight high entropy alloy synthesizes using arc melting with a mass ratio of AlCrFeMnTix(0.1,0.15,0.2). The synthesized HEA is comprised of a mixture of body center cubic (bcc) and ordered bcc (L21) solid solution phases. The synthesized HEAs have heat treated at 650C, 800C, and 1150C for 1hr, 4hr after solutionized at 1150C for 2 hr to understand the effect of …

Estimation Of Joint Moments During Turning Maneuvers In Alpine Skiing Using A Three Dimensional Musculoskeletal Skier Model And A Forward Dynamics Optimization Framework, Dieter Heinrich, Antonie J. Van Den Bogert, Werner Nachbauer

Mechanical Engineering Faculty Publications

In alpine skiing, estimation of the joint moments acting onto the skier is essential to quantify the loading of the skier during turning maneuvers. In the present study, a novel forward dynamics optimization framework is presented to estimate the joint moments acting onto the skier incorporating a three dimensional musculoskeletal model (53 kinematic degrees of freedom, 94 muscles). Kinematic data of a professional skier performing a turning maneuver were captured and used as input data to the optimization framework. In the optimization framework, the musculoskeletal model of the skier was applied to track the experimental data of a skier and …

Mechanistic Undrestanding Of Amorphization In Iron-Based Soft Magnetic Materials, Taban Larimian

ETD Archive

Iron-based magnetic alloys possess very good magnetic and mechanical properties. Among these alloys Fe-Si-B-based alloys show outstanding saturation magnetization and coercivity which makes them great candidates for many industrial applications. Addition of certain elements to the Fe-Si-B base is proven to improve the homogeneity and fineness of microstructure as well as enhance the magnetic behavior of these alloys. In this research work, we have studied the effect of adding copper and niobium to the Fe-Si-B base alloy. Previous studies have shown that magnetic alloys show better magnetic properties when their microstructure consists of nanocrystals embedded in an amorphous matrix. In …

Viability And Accessibility Of Urban Heat Island And Lake Microclimate Data Over Current Tmy Weather Data For Accurate Energy Demand Predictions., Irena A. Weclawiak

ETD Archive

Building Energy Simulations (BES) are necessary for designing energy-efficient systems. Open-source simulation software developed by the Department of Energy (DOE), EnergyPlus (EP) provides Typical Meteorological Year (TMY) weather data that consists of a 15-year average. Two major concerns about this data are the inability to detect extreme conditions and limited data locations. There is a greater number of Microclimate (MC) stations that can be used for simulations, but it involves time-consuming data preparation to match the EP format. This study investigated the effects of Urban Heat Island (UHI) and the MC of Lake Erie. A comparison of the MC data …

An Evaluation And Economic Analysis Of A Water Main Geothermal System In A Residential Space, Brian L. Kohut

ETD Archive

Iron-based magnetic alloys possess very good magnetic and mechanical properties. Among these alloys Fe-Si-B-based alloys show outstanding saturation magnetization and coercivity which makes them great candidates for many industrial applications. Addition of certain elements to the Fe-Si-B base is proven to improve the homogeneity and fineness of microstructure as well as enhance the magnetic behavior of these alloys. In this research work, we have studied the effect of adding copper and niobium to the Fe-Si-B base alloy. Previous studies have shown that magnetic alloys show better magnetic properties when their microstructure consists of nanocrystals embedded in an amorphous matrix. In …

Antagonistic Co-Contraction Can Minimize Muscular Effort In Systems With Uncertainty, Anne D. Koelewijn, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Muscular co-contraction of antagonistic muscle pairs is often observed in human movement, but it is considered inefficient and it can currently not be predicted in
simulations where muscular effort or metabolic energy are minimized. Here, we investigated the relationship between minimizing effort and muscular co-contraction
in systems with random uncertainty to see if muscular co-contraction can minimize effort in such system. We also investigated the effect of time delay in the muscle, by varying the time delay in the neural control as well as the activation time constant.We solved optimal control problems for a one-degree-of-freedom pendulum actuated by two identical …