3,002 research outputs found

    The ALICE TPC, a large 3-dimensional tracking device with fast readout for ultra-high multiplicity events

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    The design, construction, and commissioning of the ALICE Time-Projection Chamber (TPC) is described. It is the main device for pattern recognition, tracking, and identification of charged particles in the ALICE experiment at the CERN LHC. The TPC is cylindrical in shape with a volume close to 90 m^3 and is operated in a 0.5 T solenoidal magnetic field parallel to its axis. In this paper we describe in detail the design considerations for this detector for operation in the extreme multiplicity environment of central Pb--Pb collisions at LHC energy. The implementation of the resulting requirements into hardware (field cage, read-out chambers, electronics), infrastructure (gas and cooling system, laser-calibration system), and software led to many technical innovations which are described along with a presentation of all the major components of the detector, as currently realized. We also report on the performance achieved after completion of the first round of stand-alone calibration runs and demonstrate results close to those specified in the TPC Technical Design Report.Comment: 55 pages, 82 figure

    Development of a customised, self powered data logger for monitoring farm fence energizers

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    For gathering information on the performance of energizer products in the field, Gallagher Group Limited had a well out-dated data-logger which periodically monitored the voltage of the fence and transmitted the data back to base over a GSM network. However the existing data-logger had very limited capability and a new one was needed that could monitor the environment inside and around the energizer, and hopefully provide some information on why an energiser might be failing. The ideal data-logger was self powered, could last years in the field without needing to be serviced, and could collect data on the energizer without affecting it in any way. It would also collect data on as many environmental parameters as possible, such as temperature, humidity, ambient light level, lightening strikes and pressure. Ideally it would also be able to monitor the energizer voltage using a contactless measuring system. The data-logger was designed for Gallagher Animal Management Systems, the part of Gallagher Group Limited that specialises in farming equipment. The design project arose from the need for a data-logger that could monitor both the fence voltage and the environment around the fence, so that a critical explanation of why an energizer failed in the field could be found, leading to better product design in the future. It was jointly funded by Gallagher Group Limited and the Foundation of Research Science and Technology (FoRST)

    The STAR MAPS-based PiXeL detector

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    The PiXeL detector (PXL) for the Heavy Flavor Tracker (HFT) of the STAR experiment at RHIC is the first application of the state-of-the-art thin Monolithic Active Pixel Sensors (MAPS) technology in a collider environment. Custom built pixel sensors, their readout electronics and the detector mechanical structure are described in detail. Selected detector design aspects and production steps are presented. The detector operations during the three years of data taking (2014-2016) and the overall performance exceeding the design specifications are discussed in the conclusive sections of this paper

    DC Treasure Box

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    An all in one DC resource would enable electronics students to prototype circuits for labs and projects without the need for the lab equipment present on campus. The labs on campus can be physically far, closed, or overcrowded, preventing students from accessing the equipment. Roughly 75% of upper division electrical engineering students do not own power supplies, with even fewer students owning a source measurement unit (SMU). There is a significant need for a product capable of providing standard lab equipment functionality. The functionally this project provides are positive and negative DC power supplies, 4-Quadrant SMU, analog inputs and outputs, digital inputs and outputs, and other multimeter like functionality. This functionality capable of acting autonomously allowing for fast measurement sweeps. These measurement sweeps can be used for the characterization of circuits or components. Characterization and validation of circuits can save lab time and aid in debugging

    A 3U Cubesat Platform for Plant Growth Experiments

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    This thesis work presents the design, manufacturing, and ground testing of a 3U Cubesat platform intended for plant growth experiments. The structure is comprised of four identical, but independent plant growth chambers. Each of these accommodates about two cubic inches of soil, and the necessary air volume and moisture regulation to grow a fast-growing plant from seed to seed in 3-4 weeks. The plant growth is artificially stimulated by an array of light emitting diodes (LEDs) at grow light wavelengths that match the properties of chlorophyll, and is monitored by a suite of sensors: temperature, pressure, relative humidity, CO2, custom designed soil pH, soil moisture, and imaging. The latter takes periodic still pictures in the visible and infrared spectrum using LED based illumination at different wavelengths. These images are used to analyze the overall health of the plant and record the developmental stages of the plant growth. The platform is complemented with a raspberry Pi on board computer and a solar panel-based power generation system. The current scientific goal of this 3U Cubesat platform is to study the interactions of soil microbes (bacteria and fungus) and plants. The former can be a source of nutrients for plants and decrease induced stress on these in space conditions. The availability of four test chambers allow scientists to quantify changes and investigate emergent properties of the soil bacterial and fungal populations. The Cubesat design affords the opportunity to investigate the impact of physical factors such as pressure, temperature, microgravity, and space radiation on the soil bacteria and fungi, in addition to the overall plant health. While small scale biology experiments have been performed on Cubesats before, to our knowledge none of those involved plant growth stimulation and monitoring. This platform can be adapted and expanded to meet the requirements of similar scientific research

    Ultra-low Voltage Digital Circuits and Extreme Temperature Electronics Design

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    Certain applications require digital electronics to operate under extreme conditions e.g., large swings in ambient temperature, very low supply voltage, high radiation. Such applications include sensor networks, wearable electronics, unmanned aerial vehicles, spacecraft, and energyharvesting systems. This dissertation splits into two projects that study digital electronics supplied by ultra-low voltages and build an electronic system for extreme temperatures. The first project introduces techniques that improve circuit reliability at deep subthreshold voltages as well as determine the minimum required supply voltage. These techniques address digital electronic design at several levels: the physical process, gate design, and system architecture. This dissertation analyzes a silicon-on-insulator process, Schmitt-trigger gate design, and asynchronous logic at supply voltages lower than 100 millivolts. The second project describes construction of a sensor digital controller for the lunar environment. Parts of the digital controller are an asynchronous 8031 microprocessor that is compatible with synchronous logic, memory with error detection and correction, and a robust network interface. The digitial sensor ASIC is fabricated on a silicon-germanium process and built with cells optimized for extreme temperatures

    Digital control for automating feed distribution in feedlots

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    An investigation was conducted to determine the feasibility of automatic controls to automate feed distribution in feedlots. The control approach was restricted to compatibility with conventional feeding equipment. Input control signals were taken to originate from commonly available mechanical and electronic sensors. The control system was implemented with standard digital logic components;The proposed digital control system is based on a railguided, self-propelled automatic vehicle capable of delivering feed sequentially to 255 pens located on both sides of a single feeding path. A manual, closed-loop control system consisting of the following functions was developed: (1) pen identification, (2) initialization control, (3) feeding mode, (4) exit from feeding mode, (5) re-entry into feeding mode, (6) end of feeding cycle, (7) ground drive and conveyor control, (8) interface and auto/manual mode, (9) monitoring of automated system and (10) data and failure display and alarm. The control system allows either automatic or manual operation of the feeding vehicle. Digital electronic circuits capable of implementing the desired control functions were designed;The feeding cycle is manually initiated and automatically terminated when feed has been delivered to all pens requiring feed. It can be partially programmed to enable feed delivery to sections of the feedlot. Two feed rations can be delivered. The feeding status of each pen is recorded. The pen feed rations are stored in reprogrammable memories;The operation of the automated feeding system is based on the automatic identification of the feedlot pens. The number assigned to a pen is coded, using binary pulse-code modulation. Frequency-shift keying is used to transmit the coded number. The received coded number is recovered by specialized communication circuits and then validated;The control system monitors the vehicle components and the major electronic circuits to detect failures, prevent damage and produce a safe operation. Furthermore, it incorporates safety sensors and logic circuitry to meet the basic safety requirements pertaining to automated vehicles;The proposed automated feed distribution system for feedlots is expected to: (1) reduce management requirements through automatic distribution of feed to cattle raised in pens, (2) increase efficiency of feeding operation by eliminating time losses associated with secondary feed transfer, (3) eliminate damage to feedbunks through positive guidance of the vehicle by rails, and (4) save energy by eliminating secondary feed transfer

    Development of a SCADA System for Alternative Energy

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    A thesis presented to the faculty of the College of Business and Technology at Morehead State University in partial fulfillment of the requirement for the Degree Master of Science by Molom-Ochir Mijid on April 18, 2019
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