Mechanical Engineering Commons^™

Conceptualizing Stable States In Origami-Based Devices Using An Energy Visualization Approach, Jacob Greenwood, Larry L. Howell, Alex Avila, Spencer P. Magleby

Faculty Publications

In many origami-based applications, a device needs to be maintained in one or more fold states. The origami stability integration method (OSIM) presented in this paper pro- vides an approach for graphically combining various techniques to achieve stability. Existing stability techniques are also categorized into four groups based on whether they are intrinsic or extrinsic to the origami pattern and whether they exhibit gradual or non-gradual energy storage behaviors. These categorizations can help designers select appropriate techniques for their applications. The paper also contains de- sign considerations and resources for achieving stability. Finally, two case studies are presented that use …

Zero Torque Compliant Mechanisms Employing Pre-Buckled Beams, Pietro Bilancia, Samuel Porter Smith, Giovanni Berselli, Spencer P. Magleby, Larry L. Howell

Faculty Publications

The concept of a statically balanced mechanism with a single rotational degree of freedom is presented. The proposed device achieves static balancing by combining positive stiff- ness elements and negative stiffness elements within a nuclear domain. Two designs are discussed. The first is composed of an Archimedean spiral and two pinned-pinned pre-buckled beams. The overall mechanism is modeled via an analytical approach and the element dimensions are optimized. The optimal configuration is then tested through finite element analysis (FEA). A second approach replaces the spiral beam with elastic custom-shaped spline beams. An FEA optimization is performed to determine the shape …

Reflect To Connect, Sophia Rae Guzules

Liberal Arts and Engineering Studies

Engineering statics is an important course and a prerequisite for many subsequent courses for many engineering majors. It is often students’ first exposure to technical engineering sciences. Most statics concepts are addressed in ways disconnected from students’ prior experiences and interests. Utility Value Interventions (UVIs) have been employed in fields like biology and chemistry to help students connect concepts in class and their lives outside the classroom. However, UVI usage in engineering so far has been limited. In this Senior Project paper, I will describe the process that the team Critical Research in Engineering and Technology Education (CREATE) and I …

Modeling The Effects Of Radiation On Microelectromechanical Resonators, David D. Lynes

Theses and Dissertations

As the use of MEMS becomes more prolific in air, space, defense, and power applications, they will be exposed to more extreme radiation environments. This dissertation explores the effects of ionizing and nonionizing radiation on MEMS. AlN-on-Si based piezoelectric bulk acoustic wave resonators were irradiated by gamma-rays and silicon ions while measuring S-parameters in situ. Changes to the resonator and equivalent circuit parameters are extracted. The resonators demonstrated resilience against the effects of radiation-induced charge trapping. However, radiation-induced atomic displacements caused shifts to resonant frequency. From these data, an atomistic model is derived to describe the relationship between radiation type …

Shock Induced Trailing Edge Separation Effect On F-16 Limit-Cycle Oscillation, Eric D. Stubblefield

Theses and Dissertations

No abstract provided.

Decomposition Of The Skin-Friction Coefficient Of Compressible Boundary Layers, Dongdong Xu, Pierre Ricco, Lian Duan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We derive an integral formula for the skin-friction coefficient of compressible boundary layers by extending the formula of Elnahhas and Johnson ["On the enhancement of boundary layer skin friction by turbulence: An angular momentum approach, "J. Fluid Mech. 940, A36 (2022)] for incompressible boundary layers. The skin-friction coefficient is decomposed into the sum of the contributions of the laminar coefficient, the change of the dynamic viscosity with the temperature, the Favre-Reynolds stresses, and the mean flow. This decomposition is applied to numerical data for laminar and turbulent boundary layers, and the role of each term on the wall-shear stress is …

Ultrasonic Mapping Needle, Katie R. Stone, Stu Bembenek

Mechanical Engineering

When gaining access to a vein or organ for the purpose of ablation or other reasons, the common procedural method of entry is to use the Seldinger technique. This has been the standard entry procedure since its introduction in 1953, and the technique has not been modified during this time. While effective, it is prone to complication as it relies solely on the operator's precision and experience. It is our task and goal to develop a modifying kit for this procedure that would aid the operator in this process. It would make use of mapping technology and standard products used …

Trajectory-Tracking Control Of The Ball-And-Plate System, Dominic E. Riccoboni

Master's Theses

The Mechatronics group in the Mechanical Engineering department of Cal Poly is interested in creating a demonstration of a ball-and-plate trajectory tracking controller on hardware. The display piece will serve to inspire engineering students to pursue Mechatronics and control theory as an area of study. The ball-and-plate system is open-loop unstable, underactuated, and has complicated, nonlinear equations of motion. These features present substantial challenges for control - especially if the objective is trajectory tracking. Because the system is underactuated, common nonlinear trajectory tracking control techniques are ineffective. This thesis lays out a theoretical foundation for controlling the hardware.

Several important …

Recent Advances In Centrifugal Spinning And Their Applications In Tissue Engineering, Shaik Merkatur Hakim Marjuban, Musfira Rahman, Syeda Sharmin Duza, Mohammad Boshir Ahmed, Dinesh K. Patel, Md Saifur Rahman, Karen Lozano

Mechanical Engineering Faculty Publications

Over the last decade, researchers have investigated the potential of nano and microfiber scaffolds to promote wound healing, tissue regeneration, and skin protection. The centrifugal spinning technique is favored over others due to its relatively straightforward mechanism for producing large quantities of fiber. Many polymeric materials have yet to be investigated in search of those with multifunctional properties that would make them attractive in tissue applications. This literature presents the fundamental process of fiber generation, and the effects of fabrication parameters (machine, solution) on the morphologies such as fiber diameter, distribution, alignment, porous features, and mechanical properties. Additionally, a brief …

Automated Combustion Model Classification For Char Particle Distributions Using 3-D Morphology Analysis And Pore-Resolving Cfd Simulations, Dongyu Liang, Simcha L. Singer

Mechanical Engineering Faculty Research and Publications

Combustion of pulverized coal involves millions of particles with a distribution of morphologies. A workflow is presented to characterize, classify, and model distributions of highly porous coal char particles. To understand the impacts of morphology, 3-D pore-resolving combustion simulations for 150 particles imaged with micro-CT are first performed. To facilitate modeling distributions of morphology in reactor-scale CFD, a machine learning algorithm is then trained to classify particles according to their expected combustion behavior and to select an accurate, computationally efficient 1-D particle-scale combustion model. Whereas existing approaches classify particles solely according to morphology and use 2-D measurements, the present approach …

Detonation Confinement In A Second-Generation Radial Rotating Engine, John T. Ursino

Theses and Dissertations

In recent years, Rotating Detonation Engines (RDEs) have been coupled with turbomachinery to harness the benefits of detonative combustion. A novel type of RDE, referred to as the disk or Radial RDE (RRDE), has been developed in pursuit of length and weight savings compared to a traditional annular flow RDE. This design includes a disk-shaped device within which reactants flow from the outer radius, detonate, and exit the inner radius. In this paper several modifications have been made to a previously tested RRDE to address issues that arose with the original design. The combustion chamber diameter has been increased to …

Development Of Novel Turbomachinery Manufacturing Methods, Timothy P. Winkler

Theses and Dissertations

Compact turbine engines are of increasing interest as a means of propulsion for small, lightweight, low cost, unmanned aerial systems. This study looks to leverage advancements in novel manufacturing technology to produce turbomachinery components while simultaneously reducing costs and manufacturing time. To determine the feasibility of drop-in replacements for stock components this study focused on several research areas. This included materials research on both polymer-reinforced and ceramic materials, specimen tensile testing to determine temperature-dependent material properties, finite element analysis of multiple candidate materials, design and fabrication of a spin test rig, and physical spin testing of manufactured components to predict …

Measured Spectral, Directional Radiative Behavior Of Corrugated Surfaces, Kyle S. Meaker, Ehsan Modfidipour, Matthew R. Jones, Brian D. Iverson

Faculty Publications

Spacecraft thermal control is entirely reliant upon radiative heat transfer with its surroundings for tem- perature regulation. Current methods are often static in nature and do not provide dynamic control of radiative heat transfer. As a result, modern spacecraft thermal control systems are typically ‘cold-biased’ with radiators that are larger than necessary for many operating conditions. Deploying a variable radiator as a thermal control technique in which the projected surface area can be adjusted to provide the appro- priate heat loss for a given condition can reduce unnecessary heat rejection and reduce power require- ments. However, the radiative behavior of …

Optimal Configuration Of Extreme Fast Charging Stations Integrated With Energy Storage System And Photovoltaic Panels In Distribution Networks, Zhouquan Wu, Pradeep Bhat, Bo Chen

Michigan Tech Publications, Part 1

Extreme fast charging (XFC) for electric vehicles (EVs) has emerged recently because of the short charging period. However, the extreme high charging power of EVs at XFC stations may severely impact distribution networks. This paper addresses the estimation of the charging power demand of XFC stations and the design of multiple XFC stations with renewable energy resources in current distribution networks. First, a Monte Carlo (MC) simulation tool was created utilizing the EV arrival time and state-of-charge (SOC) distributions obtained from the dataset of vehicle travel surveys. Various impact factors are considered to obtain a realistic estimation of the charging …

Mechanical Metamaterials, Brent A. Peluso, Oliver T. Parker

Mechanical Engineering

Mechanical metamaterials are an emerging design strategy aimed at tailoring lattice structures to achieve specific properties such as negative Poisson’s ratios and guiding wave propagation. These metamaterials have received increasing attention from various application domains, including medical devices, aerospace, automobile, and infrastructure. The scope of this project is to vary a single lattice parameter and quantify its effect on the structural properties of the given 3D lattice.

Planar Element Alignment System, Benjamin E. Lavigna, Benny F. Cruz, Samuel Gierhan, Jacob Q. Henriksen

Mechanical Engineering

Precise alignment to the micron level is a necessity for microfluidic/micromechanical devices to function as designed. Because of this, a micro-alignment device was commissioned by Professor Hans Mayer on behalf of the Cal Poly Microfluidics Laboratory. Prototype creation was bounded by a set of requirements including, ability to align PDMS & Silicon wafer halves to ± 10 microns, total process speed of three minutes, and total budget of $3000. Some major design hurdles included an ability to verify alignment, possible non-planar alignment pieces, and an inability to contact any point on the face of the alignment pieces after bonding treatment. …

Adsorption Of Methylene Blue On Papaya Bark Fiber: Equilibrium, Isotherm And Kinetic Perspectives, Sumaya Tarannum Nipa, Nawrin Rahman Shefa, Shahanaz Parvin, Most Afroza Khatun, Md Jahangir Alam, Sujan Chowdhury, M. Azizur R. Khan, Sk Md Ali Zaker Shawon, Biplob K. Biswas, Md. Wasikur Rahman

Mechanical Engineering Faculty Publications

Rapid population growth and industrial expansion lead us to be habitat of a polluted planet. One of the major pollutants that badly affect the ecosystem being organic dyes released from various chemical industries where cleaner production concept is straightway adopted. Papaya (Carica papaya) bark fiber (PBF) is a natural product used for Methylene Blue (MB) dye removal as a cost–effective adsorbent from aqueous solution by batch method. Several parameters as the effect of pH, initial dye concentration, contact time, and adsorbent dosage were studied and optimized for maximum dye recovery. Reaction kinetics of the process and Langmuir and Freundlich adsorption …

Material Property Dependence Of Nanoparticle Silicon Carbide Alloying In Additively Manufactured Molybdenum, Andrew P. Mason

Theses and Dissertations

The structural performance of additively manufactured Mo printed by LPBF can be significantly improved by nanoparticle alloying. Previous AFIT studies of SiC nanoparticle addition conducted by Ellsworth (2022) et al. demonstrated increased powder consolidation, leading to reduced porosity, increased microhardness, and a shift in atomic defect concentrations. The addition of defected SiC particles is proposed to reduce in situ oxidation by acting as a sacrificial oxidizing agent and contributing to the formation of Mo disilicide secondary phases. This study investigated the relationship between laser powder bed fusion Mo microscale and nanoscale properties with varying SiC particle size while maintaining a …

Design Of International Airport Hybrid Renewable Energy System, Aviti Thadei Mushi

Tanzania Journal of Engineering and Technology (TJET)

This paper presents the design and simulation of a hybrid renewable energy system utilizing solar and wind energy sources with a backup generator. The demand for reliable electric energy in support of investments in large social and economic development activities such as airport operations has been an agenda worldwide. In Tanzania, Mwanza International Airport (MIA) expects to consume about 18 MVA of electric power annually to support its operations for the next 25 years. About 78-80% of the world's commercial energy comes from fossil fuels. Non-renewable fuels and other negative effects contribute to global warming through greenhouse gas emissions and …

Extraction And Characterization Of Collagen From Cattle Horns For Potential Wound Healing, Yeriko Halson

Tanzania Journal of Engineering and Technology (TJET)

The need for bandages and gauze for wound dressing and healing is inevitable due to the high increase in accidents. Most of the material used for the production of bandages and gauzes for wound healing are from non-renewable synthetic material. The sustainability of non renewable resources is at jeopardy due to the health and associated environmental impact. Consequently, the use of naturally occurring and biodegradable material is a promising solution to the sustainability challenges of synthetic material. In this paper, the extraction of collagen films from cattle horns for potential wound healing is reported. Collagen was extracted from cattle horns …

Studying Dielectric Losses Of Serially Combined Silicone Rubber And Epoxy Resin, Aviti Thadei Mushi

Tanzania Journal of Engineering and Technology (TJET)

High voltage outdoor insulation systems are conventionally ceramics and glass with several advantages, such as proven in the field, excellent dielectric properties, durability, and long life. However, they are heavy, attract vandals and break easily, and they can lose their dielectric properties easily when subjected to high voltage transients, arcing, and surges. To curb this, polymer insulators are used because they have excellent dielectric properties, such as those of ceramics and glass, with the added advantages that they do not break easily and recover their lost dielectric properties after any electrical transients. Therefore, this paper investigates the dielectric properties of …

Factors Influencing Total Productive Maintenance Implementation For Thermal Generation Plants, Ismail W. R. Taifa Dr

Tanzania Journal of Engineering and Technology (TJET)

This study accepts that the technical and administrative factors can amplify effective total productive maintenance (TPM) implementation at thermal generation plants. It is noted that there is a limited number of studies that have attempted to understand the subject of TPM implementation in the energy sector. Noting this shortcoming, the authors thought it crucial to generate empirical evidence on the factors influencing effective TPM implementation for thermal generation plants, with evidence from gas-fired plants. A sample of 88 respondents was selected and consulted. Data were collected through questionnaires and analyzed quantitatively by inferential statistics and qualitatively through thematic analysis using …

Crack Detection In An Aluminium Oxide Grinding Wheel By Impact Hammer Tests, Yubin Lee, David Turcic, Dan Danks, Chien Wern

Mechanical and Materials Engineering Faculty Publications and Presentations

Grinding is widely used as the last step of the manufacturing process when a good surface finish and precise dimensional tolerances are required. However, if the grinding wheels have cracks, they may lead to a hazardous working environment and produce poor tolerance in machined products. Therefore, grinding wheels should be inspected for cracks before being mounted onto the machine. In this study, a novel method of finding possible internal cracks in the aluminium oxide grinding wheel will be explored by examining the natural frequency and displacement of wheels using an impact hammer testing method. Grinding wheels were cracked into two …

Multifunctional Microgel-Based Cream Hydrogels For Postoperative Abdominal Adhesion Prevention, Bo Liu, Yunfan Kong, Olawale A. Alimi, Mitchell Kuss, Huiyin Tu, Wenfeng Hu, Abu Rafay, Kumar Vikas, Wen Shi, Megan Lerner, William L. Berry, Yulong Li, Mark A. Carlson, Bin Duan

Department of Mechanical and Materials Engineering: Faculty Publications

Postoperative abdominal adhesions are a common problem after surgery and can produce serious complications. Current anti-adhesive strategies focus mostly on physical barriers and are unsatisfactory and inefficient. In this study, we designed and synthesized advanced injectable cream-like hydrogels with multiple functionalities, including rapid gelation, self-healing, anti-oxidation, anti-inflammation, and anti-cellular adhesion. The multifunctional hydrogels were facilely formed by the conjugation reaction of epigallocatechin gallate (EGCG) and hyaluronic acid (HA)-based microgels and polyvinyl alcohol (PVA) based on the dynamic boronic ester bond. The physicochemical properties of the hydrogels including anti-oxidative and anti-inflammatory activities were systematically characterized. A mouse cecum-abdominal wall adhesion model …

Sensible Heat Bean Cooker, Casiana Lwiwa

Tanzania Journal of Engineering and Technology (TJET)

Alternative cooking energy to replace wood fuels is needed in the African context. Liquified Natural Gas (LNG) is a solution but is still based on burning fossil fuel. Electrical cookers can be an alternative as well. However, for off-grid systems this means electrical batteries are required, as the solar electricity from Photovoltaic (PV) panels is intermittent, and as cooking is also to be made after sunset. Heat storage technologies can provide solutions where available energy is stored in the form of heat for cooking when needed. The challenge is then to develop systems which are robust, safe, and technically simple. …

Preparation And Characterization Of Microporous Cellulose Membranes As Potential Pathogen Filters, Peresi M. Bulemo

Tanzania Journal of Engineering and Technology (TJET)

Growth and development in the textile and fashion industry have resulted in the generation of large amounts of industrial pre consumer textile wastes. It is estimated that 10 to 20% of textile fabrics are wasted during garment manufacturing, with most of the wastes being burned or landfilled. Reusing pre-consumer fabric wastes is therefore considered a viable approach to alleviate environmental impacts associated with their disposal. To achieve a higher porosity membrane, pre-consumer cotton fabrics were partially dissolved in a solution of dimethyl acetamide (DMAc) and lithium chloride (LiCl), and the resulting fibre suspension was utilized to prepare a microporous cellulose …

Cellulose-Keratin Supramolecular Composite: Conformation By Combined Fourier Transform Spectroscopy And Partial Least Square Regression Coefficient, Ngesa Ezekiel Mushi Dr

Tanzania Journal of Engineering and Technology (TJET)

Keratin and cellulose are important nano components with excellent mechanical and biological properties. However, the preparation route through dissolution in organic solvents to make manmade materials is challenging because of their intensive bonding interaction characteristics. Structural modification of the natural attributes is difficult to maintain after polymer regeneration. A new technique by a green route was devised to dissolve keratin from wool, hair, and feather with cellulose in situ using 1-Butyl-3-methylimidazolium chloride [BMIm] + Cl- ionic liquid as a solvent. The mixture of keratin and cellulose homogeneously and synergistically resulted in a supramolecular composite film through non-derivatized mechanochemical interactions. The …

Development Of Solar Pv Systems For Mini-Grid Applications In Tanzania, Seleman Mayanjo

Tanzania Journal of Engineering and Technology (TJET)

Access to electricity offers great benefits to development through the provision of reliable and efficient energy sources in the country. Majority of the population living in the remote and rural areas of developing countries mostly sub-Saharan Africa are not supplied with electricity. Although the governments through their electricity companies put their effort to extends the grid distribution networks to remote and rural areas still the coverage were not sufficiently enough due to growing demands for safe and reliable electricity. However, solar as a source of energy remains the least utilized energy source in many countries including Tanzania. Solar Photovoltaic (PV) …

Comparison Of On-Line Partial Discharge Detection Techniques For High Voltage Power Cable Joints And Terminations, Aviti Thadei Mushi

Tanzania Journal of Engineering and Technology (TJET)

Cable joints and terminations play a vital role in providing dependable electrical connection, mechanical support and physical safeguard. These provide electrical stress control to shielded power cables. Despite their usefulness, they suffer from partial discharges (PD) because of enhanced voltage stress, moisture ingress and poor workmanship (during installation). Therefore, it is necessary to undertake on-line PD detection to determine their state. Some of these techniques are capacitive coupler (CC); acoustic emission (AE); and high frequency current transducer (HFCT). This article presents a literature review of these techniques based on the cost, availability, and applicability. The comparative analysis is also provided …

Optimal Energy Management For Off-Grid Hybrid Renewable Energy Systems, Owdean M. Suwi

Tanzania Journal of Engineering and Technology (TJET)

A photovoltaic (PV)/wind/battery/Generator-Set hybrid power system's energy dispatch is discussed in this research, along with the ideal solution. The optimization model enables the hybrid power system's generating devices to share power appropriately. The main goals are to minimize fuel consumption and costs and maximize the usage of Renewable Energy Sources (RES). The proposed simulation plan succeeds in lowering fuel costs because the diesel generator only kicks on at night and in the early morning when the energy from RES is insufficient to supply the load. The load is supplied with power, and the battery is charged throughout the day, when …