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Full-Text Articles in Mechanical Engineering

Droop Control In Dq Coordinates For Fixed Frequency Inverter-Based Ac Microgrids, Mohamed Toub, Mehrzad Mohammadi Bijaieh, Wayne Weaver, Rush D. Robinett Iii, Mohamed Maaroufi, Ghassane Aniba Oct 2019

Droop Control In Dq Coordinates For Fixed Frequency Inverter-Based Ac Microgrids, Mohamed Toub, Mehrzad Mohammadi Bijaieh, Wayne Weaver, Rush D. Robinett Iii, Mohamed Maaroufi, Ghassane Aniba

Michigan Tech Publications

This paper presents a proof-of-concept for a novel dq droop control technique that applies DC droop control methods to fixed frequency inverter-based AC microgrids using the dq0 transformation. Microgrids are usually composed of distributed generation units (DGUs) that are electronically coupled to each other through power converters. An inherent property of inverter-based microgrids is that, unlike microgrids with spinning machines, the frequency of the parallel-connected DGUs is a global variable independent from the output power since the inverters can control the output waveform frequency with a high level of precision. Therefore, conventional droop control methods that distort the system frequency ...


Open Source Waste Plastic Granulator, Arvind Ravindran, Sean Scsavnicki, Walker Nelson, Peter Gorecki, Jacob Franz, Shane Oberloier, Theresa K. Meyer, Andrew Barnard, Joshua M. Pearce Oct 2019

Open Source Waste Plastic Granulator, Arvind Ravindran, Sean Scsavnicki, Walker Nelson, Peter Gorecki, Jacob Franz, Shane Oberloier, Theresa K. Meyer, Andrew Barnard, Joshua M. Pearce

Michigan Tech Publications

In order to accelerate deployment of distributed recycling by providing low-cost feed stocks of granulated post-consumer waste plastic, this study analyzes an open source waste plastic granulator system. It is designed, built, and tested for its ability to convert post-consumer waste, 3D printed products and waste into polymer feedstock for recyclebots of fused particle/granule printers. The technical specifications of the device are quantified in terms of power consumption (380 to 404 W for PET and PLA, respectively) and particle size distribution. The open source device can be fabricated for less than $2000 USD in materials. The experimentally measured power ...


Design Of Hydroxyapatite/Magnetite (Hap/Fe3o4) Based Composites Reinforced With Zno And Mgo For Biomedical Applications, D. Katundi, E. Bayraktar, F. Gatamorta, I. Miskioglu Oct 2019

Design Of Hydroxyapatite/Magnetite (Hap/Fe3o4) Based Composites Reinforced With Zno And Mgo For Biomedical Applications, D. Katundi, E. Bayraktar, F. Gatamorta, I. Miskioglu

Michigan Tech Publications

Hydroxyapatite (HAP-- Ca 10(PO4 )6 (OH)2 ) is a biocompatible and bioactive material that is widely used for biomedical applications, especially in bone replacements. It has good load carrying capacity; however, it lacks antibacterial property. New bio-composites based on bovine hydroxyapatite doped with, magnetite iron oxide (HAP/ Fe3 O4 ) matrix reinforced with ZnO and MgO nanoparticles are proposed for biomedical applications that provide improved antibacterial activity with potential to be used in magnetic therapy. Microwave sintering was used to manufacture the composites. The microstructure evolution in these composites were studied by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy ...


Optimal And Decentralized Control Strategies For Inverter-Based Ac Microgrids, Michael D. Cook, Eddy H. Trinklein, Gordon Parker, Rush D. Robinett Iii, Wayne Weaver Sep 2019

Optimal And Decentralized Control Strategies For Inverter-Based Ac Microgrids, Michael D. Cook, Eddy H. Trinklein, Gordon Parker, Rush D. Robinett Iii, Wayne Weaver

Michigan Tech Publications

This paper presents two control strategies: (i) An optimal exergy destruction (OXD) controller and (ii) a decentralized power apportionment (DPA) controller. The OXD controller is an analytical, closed-loop optimal feedforward controller developed utilizing exergy analysis to minimize exergy destruction in an AC inverter microgrid. The OXD controller requires a star or fully connected topology, whereas the DPA operates with no communication among the inverters. The DPA presents a viable alternative to conventional P−ω/Q−V droop control, and does not suffer from fluctuations in bus frequency or steady-state voltage while taking advantage of distributed storage assets necessary for the ...


Docking Control Of An Autonomous Underwater Vehicle Using Reinforcement Learning, Enrico Anderlini, Gordon Parker, Giles Thomas Aug 2019

Docking Control Of An Autonomous Underwater Vehicle Using Reinforcement Learning, Enrico Anderlini, Gordon Parker, Giles Thomas

Michigan Tech Publications

To achieve persistent systems in the future, autonomous underwater vehicles (AUVs) will need to autonomously dock onto a charging station. Here, reinforcement learning strategies were applied for the first time to control the docking of an AUV onto a fixed platform in a simulation environment. Two reinforcement learning schemes were investigated: one with continuous state and action spaces, deep deterministic policy gradient (DDPG), and one with continuous state but discrete action spaces, deep Q network (DQN). For DQN, the discrete actions were selected as step changes in the control input signals. The performance of the reinforcement learning strategies was compared ...


Stability Analysis On Nonequilibrium Supersonic Boundary Layer Flow With Velocity-Slip Boundary Conditions, Xin He, Chunpei Cai Jul 2019

Stability Analysis On Nonequilibrium Supersonic Boundary Layer Flow With Velocity-Slip Boundary Conditions, Xin He, Chunpei Cai

Michigan Tech Publications

This paper presents our recent work on investigating velocity slip boundary conditions’ effects on supersonic flat plate boundary layer flow stability. The velocity-slip boundary conditions are adopted and the flow properties are obtained by solving boundary layer equations. Stability analysis of two such boundary layer flows is performed by using the Linear stability theory. A global method is first utilized to obtain approximate discrete mode values. A local method is then utilized to refine these mode values. All the modes in these two scenarios have been tracked upstream-wisely towards the leading edge and also downstream-wisely. The mode values for the ...


Mapping Modeled Exposure Of Wildland Fire Smoke For Human Health Studies In California, Patricia Koman, Michael Billmire, Kirk Baker, Ricardo De Majo, Frank Anderson, Sumi Hoshiko, Brian Thelen, Nancy H. F. French Jun 2019

Mapping Modeled Exposure Of Wildland Fire Smoke For Human Health Studies In California, Patricia Koman, Michael Billmire, Kirk Baker, Ricardo De Majo, Frank Anderson, Sumi Hoshiko, Brian Thelen, Nancy H. F. French

Michigan Tech Publications

Wildland fire smoke exposure affects a broad proportion of the U.S. population and is increasing due to climate change, settlement patterns and fire seclusion. Significant public health questions surrounding its effects remain, including the impact on cardiovascular disease and maternal health. Using atmospheric chemical transport modeling, we examined general air quality with and without wildland fire smoke PM2.5. The 24-h average concentration of PM2.5 from all sources in 12-km gridded output from all sources in California (2007–2013) was 4.91 μg/m3. The average concentration of fire-PM2.5 in California by year ...


Mechanical Properties And Applications Of Recycled Polycarbonate Particle Material Extrusion-Based Additive Manufacturing, Matthew J. Reich, Aubrey Woern, Nagendra Gautam Tanikella, Joshua M. Pearce May 2019

Mechanical Properties And Applications Of Recycled Polycarbonate Particle Material Extrusion-Based Additive Manufacturing, Matthew J. Reich, Aubrey Woern, Nagendra Gautam Tanikella, Joshua M. Pearce

Michigan Tech Publications

Past work has shown that particle material extrusion (fused particle fabrication (FPF)/fused granular fabrication (FGF)) has the potential for increasing the use of recycled polymers in 3D printing. This study extends this potential to high-performance (high-mechanical-strength and heat-resistant) polymers using polycarbonate (PC). Recycled PC regrind of approximately 25 mm2 was 3D printed with an open-source Gigabot X and analyzed. A temperature and nozzle velocity matrix was used to find useful printing parameters, and a print test was used to maximize the output for a two-temperature stage extruder for PC. ASTM type 4 tensile test geometries as well as ...


Open Source Completely 3-D Printable Centrifuge, Salil S. Sule, Aliaksei Petsiuk, Joshua M. Pearce May 2019

Open Source Completely 3-D Printable Centrifuge, Salil S. Sule, Aliaksei Petsiuk, Joshua M. Pearce

Michigan Tech Publications

Centrifuges are commonly required devices in medical diagnostics facilities as well as scientific laboratories. Although there are commercial and open source centrifuges, the costs of the former and the required electricity to operate the latter limit accessibility in resource-constrained settings. There is a need for low-cost, human-powered, verified, and reliable lab-scale centrifuges. This study provides the designs for a low-cost 100% 3-D printed centrifuge, which can be fabricated on any low-cost RepRap-class (self-replicating rapid prototyper) fused filament fabrication (FFF)- or fused particle fabrication (FPF)-based 3-D printer. In addition, validation procedures are provided using a web camera and free and ...


Capillary Penetration Method For Measuring Wetting Properties Of Carbon Ionomer Films For Proton Exchange Membrane Fuel Cell (Pemfc) Applications, Sofyane Abbou, Kazuya Tajiri, K. T. Alofari, Ezequiel F. Medici, A. T. Haug, Jeffrey S. Allen Apr 2019

Capillary Penetration Method For Measuring Wetting Properties Of Carbon Ionomer Films For Proton Exchange Membrane Fuel Cell (Pemfc) Applications, Sofyane Abbou, Kazuya Tajiri, K. T. Alofari, Ezequiel F. Medici, A. T. Haug, Jeffrey S. Allen

Michigan Tech Publications

In this work, capillary rise experiments were performed to assess the wetting properties of carbon-ionomer (CI) films. The samples were attached to a micro-balance and then immersed into liquid water to (i) measure the mass gain from the liquid uptake and (ii) estimate the (external) contact angle to water (typical value around 140°). The results showed that drying the CI films under low vacuum significantly impacted the CI film wettability. The influence of the ionomer content on the CI films’ wettability was investigated with various ionomer to carbon (I/C) ratios: 0.8, 1.0, 1.2 and 1.4 ...