580 research outputs found
Adaptive Electricity Scheduling in Microgrids
Microgrid (MG) is a promising component for future smart grid (SG)
deployment. The balance of supply and demand of electric energy is one of the
most important requirements of MG management. In this paper, we present a novel
framework for smart energy management based on the concept of
quality-of-service in electricity (QoSE). Specifically, the resident
electricity demand is classified into basic usage and quality usage. The basic
usage is always guaranteed by the MG, while the quality usage is controlled
based on the MG state. The microgrid control center (MGCC) aims to minimize the
MG operation cost and maintain the outage probability of quality usage, i.e.,
QoSE, below a target value, by scheduling electricity among renewable energy
resources, energy storage systems, and macrogrid. The problem is formulated as
a constrained stochastic programming problem. The Lyapunov optimization
technique is then applied to derive an adaptive electricity scheduling
algorithm by introducing the QoSE virtual queues and energy storage virtual
queues. The proposed algorithm is an online algorithm since it does not require
any statistics and future knowledge of the electricity supply, demand and price
processes. We derive several "hard" performance bounds for the proposed
algorithm, and evaluate its performance with trace-driven simulations. The
simulation results demonstrate the efficacy of the proposed electricity
scheduling algorithm.Comment: 12 pages, extended technical repor
Poultry Farm Security Gate: Autonomous Vehicle Recognition System
This project addresses the lack of security on access roads to broiler poultry farms in Tennessee by creating a system that autonomously recognizes vehicles as they approach the farm property. Many of these farms lack gates with proper security, making them vulnerable to vandalism and risking their biosecurity. Allowing all feed trucks entry to the farms is a vital requirement of the design in order to avoid interrupting operations on the farm. To address this issue, this project utilizes a combination of automated license plate reading software and light detection and ranging sensors (LiDAR) to autonomously recognize a vehicle and determine if it should be allowed access to the poultry farm. This is accomplished by taking a picture of the license plate of an approaching vehicle, reading the characters on the license plate, and comparing it to a database of license plates with associated permissions to the farm. If the vehicle’s license plate is in the database, the system will signal the gate to either open or remain closed accordingly. If the vehicle’s license plate is not in the database or it is not recognized, the system will determine if it will be given entry based on data collected from the LiDAR sensors. Two LiDAR sensors are utilized in the system. One LiDAR is used to count the vehicle\u27s axles as they pass through, and the second is used to find the height of the vehicle as it passes through. This information can be used to determine if a vehicle is a large truck. Specifically, if the measured vehicle height and number of axles are representative of a feed truck approaching the farm, the system will automatically allow it access. If the system doesn’t recognize the vehicle, whether or not it is determined to be a large truck by the LiDAR sensors, the system will save a picture and the license plate number of the vehicle for the farm producer to review and add to the database for future uses. Overall, this system will improve poultry farm security while remaining autonomous and unobtrusive to daily farm operations
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Avian malaria co-infections confound infectivity and vector competence assays of Plasmodium homopolare.
Currently, there are very few studies of avian malaria that investigate relationships among the host-vector-parasite triad concomitantly. In the current study, we experimentally measured the vector competence of several Culex mosquitoes for a newly described avian malaria parasite, Plasmodium homopolare. Song sparrow (Melospiza melodia) blood infected with a low P. homopolare parasitemia was inoculated into a naïve domestic canary (Serinus canaria forma domestica). Within 5 to 10 days post infection (dpi), the canary unexpectedly developed a simultaneous high parasitemic infection of Plasmodium cathemerium (Pcat6) and a low parasitemic infection of P. homopolare, both of which were detected in blood smears. During this infection period, PCR detected Pcat6, but not P. homopolare in the canary. Between 10 and 60 dpi, Pcat6 blood stages were no longer visible and PCR no longer amplified Pcat6 parasite DNA from canary blood. However, P. homopolare blood stages remained visible, albeit still at very low parasitemias, and PCR was able to amplify P. homopolare DNA. This pattern of mixed Pcat6 and P. homopolare infection was repeated in three secondary infected canaries that were injected with blood from the first infected canary. Mosquitoes that blood-fed on the secondary infected canaries developed infections with Pcat6 as well as another P. cathemerium lineage (Pcat8); none developed PCR detectable P. homopolare infections. These observations suggest that the original P. homopolare-infected songbird also had two un-detectable P. cathemerium lineages/strains. The vector and host infectivity trials in this study demonstrated that current molecular assays may significantly underreport the extent of mixed avian malaria infections in vectors and hosts
Characterization of a CCD array for Bragg spectroscopy
The average pixel distance as well as the relative orientation of an array of
6 CCD detectors have been measured with accuracies of about 0.5 nm and 50
rad, respectively. Such a precision satisfies the needs of modern crystal
spectroscopy experiments in the field of exotic atoms and highly charged ions.
Two different measurements have been performed by illuminating masks in front
of the detector array by remote sources of radiation. In one case, an aluminum
mask was irradiated with X-rays and in a second attempt, a nanometric quartz
wafer was illuminated by a light bulb. Both methods gave consistent results
with a smaller error for the optical method. In addition, the thermal expansion
of the CCD detectors was characterized between -105 C and -40 C.Comment: Submitted to Review of Scientific Instrument
Measurement of the charged pion mass using X-ray spectroscopy of exotic atoms
The transitions in pionic nitrogen and muonic oxygen were measured
simultaneously by using a gaseous nitrogen-oxygen mixture at 1.4\,bar. Due to
the precise knowledge of the muon mass the muonic line provides the energy
calibration for the pionic transition. A value of
(139.57077\,\,0.00018)\,MeV/c (\,1.3ppm) is derived for the
mass of the negatively charged pion, which is 4.2ppm larger than the present
world average
Design of a ZVS PWM inverter for a brushless DC motor in an EMA application
The Component Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently investigating the use of electromechanical actuators for use in space transportation applications such as Thrust Vector Control (TVC). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 Vdc. This paper will discuss the design and implementation of a zero-voltage-switched PWM (Pulse Width Modulation) inverter which operates from a 270 Vdc source at currents up to 100 A
Cross Cultural Variation in the Neurodevelopmental Assessment of Children – The Cultural and Neurological to 2nd Language Acquisition and Children with Autism
Using Video Solutions as an Instructional Aid in Teaching Introductory Engineering Circuit Analysis
Abstract Regardless of how technology is being used in the classroom as an instructional tool, it is still imperative to the student's learning in all engineering courses to receive numerous examples with step-by-step explanations from the instructor. The question, however, is how can the instructor provide students immediate and step-by-step assistance outside of class while the students are working homework problems or studying the material? Discussed in this paper is the use of video solutions, available via the Internet, as an instructional aid in teaching an introductory engineering circuit analysis course followed by a discussion of preliminary student feedback about the videos of problem solutions. Overall, the students rated their experiences using the videos as very good
A Hybrid Nonlinear Control Scheme for Active Magnetic Bearings
A nonlinear control scheme for active magnetic bearings is presented in this work. Magnet winding currents are chosen as control inputs for the electromechanical dynamics, which are linearized using feedback linearization. Then, the desired magnet currents are enforced by sliding mode control design of the electromagnetic dynamics. The overall control scheme is described by a multiple loop block diagram; the approach also falls in the class of nonlinear controls that are collectively known as the 'integrator backstepping' method. Control system hardware and new switching power electronics for implementing the controller are described. Various experiments and simulation results are presented to demonstrate the concepts' potentials
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