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Articles 1 - 9 of 9
Full-Text Articles in Engineering
Ensemble Machine Learning And Forecasting Can Achieve 99% Uptime For Rural Handpumps, Daniel L. Wilson, Jeremy R. Coyle, Evan A. Thomas
Ensemble Machine Learning And Forecasting Can Achieve 99% Uptime For Rural Handpumps, Daniel L. Wilson, Jeremy R. Coyle, Evan A. Thomas
Mechanical and Materials Engineering Faculty Publications and Presentations
Broken water pumps continue to impede efforts to deliver clean and economically-viable water to the global poor. The literature has demonstrated that customers’ health benefits and willingness to pay for clean water are best realized when clean water infrastructure performs extremely well (>99% uptime). In this paper, we used sensor data from 42 Afridev-brand handpumps observed for 14 months in western Kenya to demonstrate how sensors and supervised ensemble machine learning could be used to increase total fleet uptime from a best-practices baseline of about 70% to >99%. We accomplish this increase in uptime by forecasting pump failures and …
A Functional Subnetwork Approach To Designing Synthetic Nervous Systems That Control Legged Robot Locomotion, Nicholas Szczecinski, Alexander J. Hunt, Roger Quinn
A Functional Subnetwork Approach To Designing Synthetic Nervous Systems That Control Legged Robot Locomotion, Nicholas Szczecinski, Alexander J. Hunt, Roger Quinn
Mechanical and Materials Engineering Faculty Publications and Presentations
A dynamical model of an animal’s nervous system, or synthetic nervous system (SNS), is a potentially transformational control method. Due to increasingly detailed data on the connectivity and dynamics of both mammalian and insect nervous systems, controlling a legged robot with an SNS is largely a problem of parameter tuning. Our approach to this problem is to design functional subnetworks that perform specific operations, and then assemble them into larger models of the nervous system. In this paper, we present networks that perform addition, subtraction, multiplication, division, differentiation, and integration of incoming signals. Parameters are set within each subnetwork to …
Turbulent Boundary Layer Features Via Lagrangian Coherent Structures, Proper Orthogonal Decomposition And Dynamic Mode Decomposition, Naseem Ali, Murat Tutkun, Raul Bayoan Cal
Turbulent Boundary Layer Features Via Lagrangian Coherent Structures, Proper Orthogonal Decomposition And Dynamic Mode Decomposition, Naseem Ali, Murat Tutkun, Raul Bayoan Cal
Mechanical and Materials Engineering Faculty Publications and Presentations
High-speed stereo PIV-measurements have been performed in a turbulent boundary layer at Reθ of 9800 in order to elucidate the coherent structures. Snapshot proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) are used to visualize the flow structure depending on the turbulent kinetic energy and frequency content. The first six POD and DMD modes show the largest and the lowest amount of energy and frequency, respectively. Lagrangian coherent structure (LCS) based on the algorithm developed using the variational theory is also applied to track the flow via attracting and repelling trajectories. The shapes and the length of the trajectories …
Development And Training Of A Neural Controller For Hind Leg Walking In A Dog Robot, Alexander J. Hunt, Nicholas Szczecinski, Roger Quinn
Development And Training Of A Neural Controller For Hind Leg Walking In A Dog Robot, Alexander J. Hunt, Nicholas Szczecinski, Roger Quinn
Mechanical and Materials Engineering Faculty Publications and Presentations
Animals dynamically adapt to varying terrain and small perturbations with remarkable ease. These adaptations arise from complex interactions between the environment and biomechanical and neural components of the animal’s body and nervous system. Research into mammalian locomotion has resulted in several neural and neuro-mechanical models, some of which have been tested in simulation, but few “synthetic nervous systems” have been implemented in physical hardware models of animal systems. One reason is that the implementation into a physical system is not straightforward. For example, it is difficult to make robotic actuators and sensors that model those in the animal. Therefore, even …
The Effectiveness Of Sanitary Inspections As A Risk Assessment Tool For Thermotolerant Coliform Bacteria Contamination Of Rural Drinking Water: A Review Of Data From West Bengal, India, Christian Snoad, Corey L. Nagel, Animesh Bhattacharya, Evan A. Thomas
The Effectiveness Of Sanitary Inspections As A Risk Assessment Tool For Thermotolerant Coliform Bacteria Contamination Of Rural Drinking Water: A Review Of Data From West Bengal, India, Christian Snoad, Corey L. Nagel, Animesh Bhattacharya, Evan A. Thomas
Mechanical and Materials Engineering Faculty Publications and Presentations
The use of sanitary inspections combined with periodic water quality testing has been recommended in some cases as screening tools for fecal contamination. We conducted sanitary inspections and tested for thermotolerant coliforms (TTCs), a fecal indicator bacteria, among 7,317 unique water sources in West Bengal, India. Our results indicate that the sanitary inspection score has poor ability to identify TTC-contaminated sources. Among deep and shallow hand pumps, the area under curve (AUC) for prediction of TTC > 0 was 0.58 (95% confidence interval [CI] = 0.53–0.61) and 0.58 (95% CI = 0.54–0.62), respectively, indicating that the sanitary inspection score was only …
Reversible Control Of The Magnetization Of Fe₃O₄ Via Lithium Ions, Guodong Wei, Lin Wei, Dong Wang, Yufeng Tian, Yanxue Chen, Shishen Yan, Liangmo Mei, Jun Jiao
Reversible Control Of The Magnetization Of Fe₃O₄ Via Lithium Ions, Guodong Wei, Lin Wei, Dong Wang, Yufeng Tian, Yanxue Chen, Shishen Yan, Liangmo Mei, Jun Jiao
Mechanical and Materials Engineering Faculty Publications and Presentations
In this report, a reversible control of Fe₃O₄ saturated magnetization by Li ions is demonstrated. A miniature Li ion battery (LIB) was assembled using a Fe₃O₄ nanoparticle layer as the active cathode. A stable magnetism modulation is realized by a nondestructive electrochemical process in which the lithium insertion results in a valence change and partial redistribution of Fe cations in the crystal structure. The relation between the discharge voltage and the chemical phases were studied by ex situ X-ray diffraction and magnetic measurement. In a suitable discharge potential range, a reversible control of Fe₃O₄ saturated magnetization was obtained without structural …
Fifty-Plus-Year Postflight Analysis Of First Fluid Experiment Aboard A Spacecraft, Mark M. Weislogel, Yongkang Chen, William J. Masica, Fred J. Kohl, Robert D. Green
Fifty-Plus-Year Postflight Analysis Of First Fluid Experiment Aboard A Spacecraft, Mark M. Weislogel, Yongkang Chen, William J. Masica, Fred J. Kohl, Robert D. Green
Mechanical and Materials Engineering Faculty Publications and Presentations
This year marks the 55th anniversary of the first fluid physics experiment performed aboard a spacecraft during the Mercury-Atlas 7 mission. Since then, NASA has conducted over 80 fluids physics experiments aboard a variety of spacecraft, many of which have enhanced the understanding of large-length-scale capillary phenomena relevant to liquid management in the weightless state. As both celebration and demonstration, the Mercury-Atlas 7 fluids experiment is revisited in light of the current understanding of large-length-scale capillary fluidics. Employing a modern numerical tool, a rich variety of experimental outcomes are discovered that were not observed during the flight experiment. Interestingly, experimental …
Anisotropic Character Of Low-Order Turbulent Flow Descriptions Through The Proper Orthogonal Decomposition, Nicholas Hamilton, Murat Tutkun, Raúl Bayoán Cal
Anisotropic Character Of Low-Order Turbulent Flow Descriptions Through The Proper Orthogonal Decomposition, Nicholas Hamilton, Murat Tutkun, Raúl Bayoán Cal
Mechanical and Materials Engineering Faculty Publications and Presentations
Proper orthogonal decomposition (POD) is applied to distinct data sets in order to characterize the propagation of error arising from basis truncation in the description of turbulence. Experimental data from stereo particle image velocimetry measurements in a wind turbine array and direct numerical simulation data from a fully developed channel flow are used to illustrate dependence of the anisotropy tensor invariants as a function of POD modes used in low-order descriptions. In all cases, ensembles of snapshots illuminate a variety of anisotropic states of turbulence. In the near wake of a model wind turbine, the turbulence field reflects the periodic …
Reversible Control Of The Magnetization Of Spinel Ferrites Based Electrodes By Lithium-Ion Migration, Guodong Wei, Lin Wei, Dong Wang, Yanxue Chen, Yufeng Tian, Shishen Yan, Liangmo Mei, Jun Jiao
Reversible Control Of The Magnetization Of Spinel Ferrites Based Electrodes By Lithium-Ion Migration, Guodong Wei, Lin Wei, Dong Wang, Yanxue Chen, Yufeng Tian, Shishen Yan, Liangmo Mei, Jun Jiao
Mechanical and Materials Engineering Faculty Publications and Presentations
Lithium-ion (Li-ion) batteries based on spinel transition-metal oxide electrodes have exhibited excellent electrochemical performance. The reversible intercalation/deintercalation of Li-ions in spinel materials enables not only energy storage but also nondestructive control of the electrodes’ physical properties. This feature will beneft the fabrication of novel Li-ion controlled electronic devices. In this work, reversible control of ferromagnetism was realized by the guided motion of Li-ions in MnFe2O4 and γ-Fe2O3 utilizing miniature lithium-battery devices. The in-situ characterization of magnetization during the Li-ion intercalation/deintercalation process was conducted, and a reversible variation of saturation magnetization over 10% was observed …