• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 241
  • 143
  • 18
  • 9
  • 6
  • 4
  • 4
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 611
  • 611
  • 139
  • 119
  • 114
  • 97
  • 92
  • 78
  • 76
  • 75
  • 71
  • 62
  • 58
  • 54
  • 52
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

AirSniffer: A Smartphone-Based Sensor Module for Personal Micro-Climate Monitoring

Smith, Jeffrey Paul 05 1900 (has links)
Environmental factors can have a significant impact on an individual's health and well-being, and a primary characteristic of environments is air quality. Air sensing equipment is available to the public, but it is often expensive,stationary, or unusable for persons without technical expertise. The goal of this project is to develop an inexpensive and portable sensor module for public use. The system is capable of measuring temperature in Celsius and Fahrenheit, heat index, relative humidity, and carbon dioxide concentration. The sensor module, referred to as the "sniffer," consists of a printed circuit board that interconnects a carbon dioxide sensor, a temperature/humidity sensor, an Arduino microcontroller, and a Bluetooth module. The sniffer is small enough to be worn as a pendant or a belt attachment, and it is rugged enough to consistently collect and transmit data to a user's smartphone throughout their workday. The accompanying smartphone app uses Bluetooth and GPS hardware to collect data and affix samples with a time stamp and GPS coordinates. The accumulated sensor data is saved to a file on the user's phone, which is then examined on a standard computer.
242

Detecting Change in Central California Coast Coho Salmon Habitat in Scotts Creek, California, from 1997–2013

Hillard, Ashley Brubaker 01 June 2015 (has links)
Scotts Creek, in Santa Cruz County, Calif., supports the southernmost extant population of Coho Salmon (Oncorhynchus kisutch) in North America. In 1997, the California Department of Fish and Game (now Fish and Wildlife) conducted an extensive habitat typing survey of mainstem Scotts Creek, describing all habitat units from the top of the estuary to the limit of anadromy approximately 12 km upstream. I repeated this survey in 2013 to (1) assess changes in the quantity and quality of instream habitat, (2) compare the current condition to goals and standards established in the federal Central California Coast (CCC) Coho Salmon Recovery Plan, and (3) identify opportunities for possible future restoration. A comparison of the two surveys revealed an overall increase in mean canopy cover, mean bank vegetation, mean percentage instream cover, pool depth diversity, and percentage riffles since 1997, and decreases in mean residual pool depth, percentage flatwater, and number of primary pools. Overall, the percentage of the total mainstem classified as pool habitat did not change between the two survey periods. Results for individual habitat metrics were more variable when the stream was broken into discrete reaches delineated by major tributary junctions. Although a large woody debris (LWD) survey was not conducted as part of the 1997 survey, contrasting our results with data collected during intervening years indicated that instream LWD has become more abundant, primarily due to increases in hard-wood species (i.e., red alder [Alnus rubra] and California bay [Umbellularia californica]). When compared to habitat goals established in the federal CCC Coho Salmon Recovery Plan, Scotts Creek has adequate canopy cover and percentage pools, but is lacking in percentage riffles, instream cover, key pieces of LWD per100 m, and percentage primary pools.
243

Metode praćenja parametara životne sredine bazirane na pametnim mernim sistemima / МETHODS OF ENVIRONMENTAL MONITORING PARAMETERS BASED ON SMART MEASUREMENT SYSTEMS

Rajs Vladimir 07 October 2015 (has links)
<p>Kako se efekat globalnog zagrevanja odigrava širom planete, tako se svetska populacija suočava sa verovatno jednim od najvažnijih socijalnih i naučnih fenomena-promenom parametara životne sredine usled zagađenja. Preduzimanje bilo kakve akcije zahteva precizna i tačna merenja parametara životne sredine u više desetina hiljada tačaka, postavljenih širom sveta. Pošto je finansijski skupo, a i praktično nemoguće napraviti tako veliki broj mernih stanica koje bi premrežile celu planetu, očigledno je da se moraju pronaći neka alternativna rešenja. Napravljen je merni sistem i realizovane su merne metode za udaljeno merenje parametara životne sredine. Ovaj sistem može biti realizovan kao stacionarna ili kao pokretna merna stanica. Radna hipoteza se zasniva na korišćenju statističke analize izmernih podataka, gde se dolazi do pretpostavke i dokaza o mogućnosti smanjenja broja senzora na mernoj stanici, jer se praćenjem jedne veličine (koncentracija ugljen-monoksida) može doći do pretpostavljene vrednosti druge veličine (koncentracija azot-dioksida) u slučaju da potiču iz istog izvora. A korišćenjem predikcije, pomoću regresionog modela &ndash; interpolacije i ekstrapolacije pokazala se mogućnost smanjenja broja mernih stanica. Naime, korišćenjem interpolacionih krivih moguće je na teritoriji jednog grada prikazati estimacije koncentracija gasova na osnovu podataka sa pokretne merne stanice. Takođe, na osnovu matematičkog ARMA modela pokazana je estimacija koncentracije gasova na osnovu prethodnih merenja.</p> / <p>As the effects of global warming are spreading globally, the world population encounters one of the most important social and scientific phenomena- changing the parameters of the environment due to pollution. Any conducted action requires precise and accurate measuring of the environmental parameters at several dozens of thousands points deployed around the world. Since financially, as well as practically, it is impossible to create such a large number of measuring stations which would network all over the planet, it is obvious that some alternative solutions must be found. A new measuring system is developed and measuring methods for remote measurement of environmental parameters are implemented. This system can be implemented as a stationary or mobile measuring station. The working hypothesis is based on the use of statistical analysis of measurement data. It leads to the possibility of reducing the number of sensors at measure station, as based on the monitoring of one value-gas concentration (the concentration of carbon monoxide) can be estimated values of other gas (the concentration of nitrogen - dioxide) in the case that they originate from the same source. Using prediction and regression models - interpolation and extrapolation have shown the possibility to reduce the number of measuring stations. Specifically, in the territory of one observedcity, by using interpolation curves, the estimation of concentrations of gases based on data from the measuring system can be shown. Also, based on a mathematical model (ARMA) estimation of concentrations of gases based on previous measurements is shown.</p>
244

Detection of Harmful Chemicals in the Air using Portable Membrane Inlet Mass Spectrometry

Kretsch, Amanda Renee 08 1900 (has links)
Portable mass spectrometry has become an important analytical tool for chemical detection and identification outside of a lab setting. Many variations and applications have been developed to benefit various fields of science. Membrane inlet mass spectrometry is used to allow certain analytes to pass into the mass spectrometer without breaking vacuum or letting in large particulate matter. These two important analytical tools have been applied to the detection of harmful chemicals in the air. Earth-based separations and reverse gas stack modelling are useful mathematical tools that can be used to locate the source of a chemical release by back calculation. Earth-based separations studies the way different molecules will diffuse and separate through the air. Reverse gas stack modelling refers to the concentration differences of a chemical in relation to its distance from its source. These four analytical techniques can be combined to quickly and accurately locate various harmful chemical releases. The same system can be used for many applications and has been tested to detect harmful chemicals within and air-handling system. The monitoring of air-handling systems can greatly reduce the threat of harm to the building occupants by detecting hazardous chemicals and shutting off the air flow to minimize human exposure.
245

Evaluation of the Use of the Bivalves Ischadium recurvum Rafinesque, 1820 and Corbicula fluminea Muller, 1774 as Biological Indicators of Relative Water Quality in Terms of Growth and Upper Temperature Tolerance

Hemming, Jon Michael 12 1900 (has links)
Growth of mussels under laboratory conditions was examined under various food regimes in different water types and temperatures. Growth was less than would be useful as an indicator and comparisons with field exposures were of minimal value. The effects of organophosphates on bivalves were examined via toxicity tests, tissue concentration, and by controlling exposure through the use of physical constraints. Upper temperature tolerance of both bivalve species was examined with respect to different acclimation temperatures and organophosphate exposures. Deviations from control exposures occurred at some temperatures. Copper effectively lowered the mean heat coma temperatures of C. fluminea at some concentrations, however, chlorine exposures did not alter heat coma temperature.
246

Improving Sinkhole Mapping Using LiDAR Data and Locating Sinkhole Hotspots in Johnson City, TN

Fasesin, Kingsley 01 December 2018 (has links)
Predicting infrastructure damage and economic impact of sinkholes requires high accuracy mapping distribution and development. The study mapped sinkholes and sinkhole hotpsots in Johnson City, TN using LiDAR-derived Digital Elevation Model (DEM) and a database of known sinkholes which were matched to LiDAR-derived depressions. For all matched depressions (n = 404), three metrics were calculated: circularity index, ratio of length to width of the Minimum Bounding Rectangle (MBR) and percent coverage of the MBR by the depression, and 3,634 new sinkholes were identified. Newly developed hotspots were identified in north Johnson City and other areas in the south near the Johnson City Medical Center. The methodology developed can be applied to identify hotspots in other small metropolitan cities and the hotspot map produced can be employed in hazard mitigation planning, resource allocation, and made available publicly to property owners and insurance companies.
247

Projecting Future Heat Wave Effects on Mortality in the United States: National Estimates Using Dynamically Downscaled Climate Projections

Li, Ying, Zhang, Yuqiang 01 June 2017 (has links)
No description available.
248

Sensor Observation Service for Environmental Monitoring Data

Mokhtary, Mandana January 2012 (has links)
The Swedish Environmental Protection Agency (Naturvårdsverket) is the public agency in Sweden with responsibility to overview the conditions of the environment and the policies related to the environmental monitoring data. Nowadays, observation data are stored in several different data models in this organization, leading to difficulties in finding, understanding and consequently using data in terms of analysis and management of environmental issues. One common model that uniformly structures observation data could largely make it easier for decision makers to find the required information. The aim of this study is to build an interoperable data model for environmental monitoring observation in Naturvårdsverket based on OGC-SWE standard formats. The proposed solution relies on Sensor Web architecture, which is the set of data model definitions andweb service specifications. Also, this methodology is based on open source components; therefore it is cost-effective for the users. The Service Oriented Architecture (SOA) is used to create a uniform model by using communication protocols such as Extensible Markup Language (XML) and Simple Object Access Protocol (SOAP). The primary findings of the thesis is that when the observation is encoded into the standard format from the beginning, then it is easier to parse these documents and find the required information for the end users without knowing how these information are gathered and stored. The client scan send a request to the Sensor Observation Service (SOS) and receive the observation that is structured based on Observation and Measurements (O&amp;M).
249

IoT Buoy for Water Quality Monitoring : Design, prototype, and test of a solar-powered, LoRaWAN-based WQM system for the smart city / IoT-boj för övervakning av vattenkvalitet

Dalla Via, Mattia January 2021 (has links)
Although water is incredibly abundant on Earth, only 2.5 % of the water reserve is freshwater, and one third of the world’s population lacks safe drinking water. Water quality monitoring (WQM) is thus a crucial asset to safeguard this invaluable resource. Gaining popularity in the 1960s, WQM has since evolved from a lab-based, labour-intensive program to an increasingly automated operation. Today, autonomous sensors automatically assess water quality, albeit with surpassed technology, complex procedures, and expensive equipment. This thesis presents a next-generation, IoT-based WQM system, capable of unparalleled high-frequency data collection at a fraction of the cost of present-day solutions, that operates via The Thing Network’s public LoRaWAN connectivity. The system is validated through a lightweight prototype buoy, which is deployed on a 14-days-long campaign in the lakes of Stockholm. The study concludes that (i) The Things Network is a promising backbone for monitoring applications in the smart city, with an estimated current 57 % coverage of Stockholm; (ii) IoT devices can harvest sufficient solar energy to deliver 30–60 messages/h all year round even at high latitudes; (iii) IoT-based WQM has the potential for unprecedented resolution, energy-efficiency, and cost-effectiveness compared to traditional industrial-grade, cellular-based systems. / Även om vatten är otroligt rikligt på jorden, är bara 2,5 % av vattenreserven sötvatten, och en tredjedel av världens befolkning saknar säkert dricksvatten. Water quality monitoring (WQM) är således en avgörande tillgång för att skydda denna ovärderliga resurs. WQM blev allt populärare på 1960-talet och har sedan dess utvecklats från ett labbaserat, arbetskrävande program till en alltmer automatiserad verksamhet. Idag bedömer autonoma sensorer automatiskt vattenkvaliteten, om än med överträffad teknik, komplexa förfaranden och dyr utrustning. Denna avhandling presenterar ett nästa generations, IoT-baserade WQM-system, som kan möta högfrekvent datainsamling utan motstycke till en bråkdel av kostnaden för dagens lösningar, som fungerar via The Things Network offentliga LoRaWAN-anslutning. Systemet valideras genom en lätt prototypboj, som används på en 14 dagar lång kampanj i Stockholms sjöar. Studien drar slutsatsen att (i) The Things Network är en lovande ryggrad för övervakning av applikationer i den smart city, med en uppskattningsvis 57 % täckning av Stockholm; (ii) IoT-enheter kan skörda tillräckligt med solenergi för att leverera 30-60 meddelanden/timme året runt även på höga breddgrader; (iii) IoT-baserat WQM har potential för oöverträffad upplösning, energieffektivitet och kostnadseffektivitet jämfört med traditionella, industriella, cellbaserade system.
250

Storm Sampling to Assess Inclement Weather Impacts on Water Quality in a Karst Watershed: Sinking Creek, Watauga Watershed, East Tennessee

McCurdy, Porcha 01 May 2020 (has links)
Escherichia coli changes in Sinking Creek, an impaired water body in the Watauga watershed of northeast Tennessee, were assessed during storm events using water samples collected with ISCO automated samplers during eight storms at two locations. Turbidity and electrical conductivity (EC) data loggers were deployed in the creek, and dissolved oxygen (DO) was measured in situ to test the stream’s water quality and reaction to inclement weather. Cotton fabric was deployed at both locations and sent to an external lab to test for the presence of Optical Brighteners (OB), which are indicators of residential wastewater. E. coli and turbidity at the creek generally increased within 2.5 hours of a rain event, remaining above the single sample standard for several hours during the storm. At the spring, E. coli became elevated within 30 minutes of precipitation onset, but generally decreased below the standard during the event.

Page generated in 0.1152 seconds