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Full-Text Articles in Mechanical Engineering

Quadcopter Control Using Single Network Adaptive Critics, Alberto Velazquez, Lei Xu, Tohid Sardarmehni Feb 2023

Quadcopter Control Using Single Network Adaptive Critics, Alberto Velazquez, Lei Xu, Tohid Sardarmehni

Mechanical Engineering Faculty Publications and Presentations

In this paper, optimal tracking control is found for an inputaffine nonlinear quadcopter using Single Network Adaptive Critics (SNAC). The quadcopter dynamics consists of twelve states and four controls. The states are defined using two related reference frames: the earth frame, which describes the position and angles, and the body frame, which describes the linear and angular velocities. The quadcopter has six outputs and four controls, so it is an underactuated nonlinear system. The optimal control for the system is derived by solving a discrete-time recursive Hamilton-Jacobi-Bellman equation using a linear in-parameter neural network. The neural network is trained to …


Reshaping The Landscape Of The Future: Software-Defined Manufacturing, Lei Xu, Lin Chen, Zhimin Gao, Hiram Moya, Weidong Shi Jul 2021

Reshaping The Landscape Of The Future: Software-Defined Manufacturing, Lei Xu, Lin Chen, Zhimin Gao, Hiram Moya, Weidong Shi

Computer Science Faculty Publications and Presentations

We describe the concept of software-defined manufacturing, which divides the manufacturing ecosystem into software definition and physical manufacturing layers. Software-defined manufacturing allows better resource sharing and collaboration, and it has the potential to transform the existing manufacturing sector.


Campus Carbon Footprint Study At A South Texas University, Monica Garcia, Christian Florez, Diego Lopez, Jongmin Kim, Maysam Pournik Feb 2021

Campus Carbon Footprint Study At A South Texas University, Monica Garcia, Christian Florez, Diego Lopez, Jongmin Kim, Maysam Pournik

Mechanical Engineering Faculty Publications and Presentations

A campus carbon footprint study was conducted at the University of Texas Rio Grande Valley, a Southern Texan university. This initiative was the school’s strategic plan to set a baseline for overall campus resource utilization status as well as to answer global requests to track and reduce campus greenhouse gas emissions and achieve greater sustainability on campus. For fiscal years of 2016 to 2018, an overall increase of campus carbon footprint was about 0.6%. The biggest increase was observed from sources owned or controlled by the school while the emissions associated with power usage decreased. The university’s carbon footprint was …


Energy And Exergy Analysis Of A Novel Multiple-Effect Vapor Chamber Distillation System For High-Salinity Wastewater Treatment, Hamidreza Shabgard, Ramkumar Parthasarathy, Ben Xu Dec 2019

Energy And Exergy Analysis Of A Novel Multiple-Effect Vapor Chamber Distillation System For High-Salinity Wastewater Treatment, Hamidreza Shabgard, Ramkumar Parthasarathy, Ben Xu

Mechanical Engineering Faculty Publications and Presentations

A novel modular thermally-driven multiple-effect vapor chamber distillation (MVCD) system is presented for compact and portable desalination applications. The MVCD system consists of several vapor chambers connected in series with the condenser section of the upstream vapor chambers serving as the evaporator section of the following effect. A heat transfer model accounting for the major thermal resistances was developed to predict the heat transfer and distilled water production rates. A mass transfer analysis was performed to evaluate the effect of the accumulation of the non-condensable gasses within the chambers. An exergy analysis was also conducted to quantify the efficiency of …


Pressure Effect On An Ocean-Based Humidification-Dehumidification Desalination Process, Yingchen Yang Oct 2019

Pressure Effect On An Ocean-Based Humidification-Dehumidification Desalination Process, Yingchen Yang

Mechanical Engineering Faculty Publications and Presentations

A new humidification-dehumidification (HDH) desalination process is proposed and analyzed. Being ocean based, the process does not produce any brine. It is largely powered jointly by solar energy, wind energy, and various types of ocean energies in a nearly natural way. A vacuum pump is employed to drive the air circulation throughout the HDH process. It is the only unit that consumes electricity. The HDH process is analyzed under various conditions, including using a low pressure (as low as to 0.2 atm) for humidification and the ambient pressure for dehumidification, running the entire HDH process around a low pressure (as …


Parametric Analysis Of A Solid Oxide Fuel Cell Auxiliary Power Unit Operating On Syngas Produced By Autothermal Reforming Of Hydrocarbon Fuels, Jun Dong, Xinhai Xu, Ben Xu, Shuyang Zhang Apr 2016

Parametric Analysis Of A Solid Oxide Fuel Cell Auxiliary Power Unit Operating On Syngas Produced By Autothermal Reforming Of Hydrocarbon Fuels, Jun Dong, Xinhai Xu, Ben Xu, Shuyang Zhang

Mechanical Engineering Faculty Publications and Presentations

A 1 kWe integrated auxiliary power unit (APU) system consisting of an autothermal reformer and a solid oxide fuel cell (SOFC) unit, as well as balance-of-plant components, was designed and analyzed. A relatively easy-to-approach SOFC model was developed in order to conveniently calculate V-I and P-I curves and the system's net efficiency at different operating conditions. The effects of steam to carbon and oxygen to carbon ratios in the reactants, channel dimensions of the SOFC unit, and hydrocarbon fuel types on the integrated APU system's performance were discussed. Five hydrocarbon fuels including diesel, Jet-A, gasoline, ethanol, and methanol were studied …