Remote Monitoring Sites Research Articles

Radiation Area Monitoring by wireless-communicating Area Monitor with Surveillance Camera

Aiming at a dose reduction and a work efficiency improvement for nuclear power plants that have high dose regions, we have developed our system of wireless-communicating Area Monitor with Surveillance Camera, and have performed an on-site test. Now we are implementing this Area Monitor with Surveillance Camera for a use as a TV camera in the controlled-area, which enables a personal computer to simultaneously display two or more dose values and site live images on the screen. For the radiation detector of this Area Monitor System, our wireless-communicating dosimeter is utilized. Image data are transmitted via a wireless Local Area Network (LAN). As a test result, image transmission of a maximum of 20 frames per second has been realized, which shows that this concept is a practical application. Remote-site monitoring also has been realized from an office desk located within the non-controlled area, adopting a Japan's wireless phone system, PHS (Personal Handy Phone) for the transmission interface.

AIR TEMPERATURE ERRORS CAUSED BY AIR FILTER AND CONDUCTION EFFECTS ON HMP45C TEMPERATURE SENSORS IN WEATHER STATIONS

For nonventilated air temperature measurements at weather stations, both ambient wind speed and solarradiation are known to affect the magnitude of air temperature measurement errors. The objective of this study is to explorethe effect of the sensors housing and to quantify any stagnation or conduction errors. The HMP45C temperature and relativehumidity sensor with a Gill radiation shield is widely used in remote monitoring sites. The use of a filter in the HMP45C leadsto loss of ventilation, while the protrusion of the sensor housing below the Gill shield exposes it to radiation loading andpotentially increased conduction of heat to the sensor. The HMP45C sensors were deployed with and without an air filter inboth standard Gill shields and in a Gill shield modified with extra plates to completely cover the base of the sensor housing.The data collected were examined using spectral analysis and statistical methods. Results show that both average airtemperature errors and variations of air temperature errors were smaller in the HMP45C sensors when themanufacturersupplied air filter was removed. The ranges of the threesigma errors can be decreased by 0.4.C to 0.7.C andthe accuracy of monthly average air temperature can be improved at least 0.1.C by employing an HMP45C without the airfilter. Results suggest that the maximum air temperature taken with the filter may reach more than 1.0.C higher than that takenwithout the filter. The major frequency component contributing to air temperature errors using the HMP45C sensor in theGill shield is the frequency of one day per cycle, which is expected. Partial radiation blocking combined with aspirationsignificantly reduces the contribution of the oneday cycle. In field tests, the R. M. Young aspirated temperature system provedvery accurate compared to an aspirated precision industrial platinum resistance thermometer (PRT).

Potential particulate impacts at the Grand Canyon from northwestern Mexico

Project MOHAVE was a major air quality and visibility research program conducted from 1990 to 1999 to investigate the causes of visibility impairment in the Grand Canyon National Park region. At Meadview, a remote monitoring site just west of the Grand Canyon National Park, on September 1 and 2, 1992, the concentrations of sulfate (3.1 and 4.3 μg sulfate/m 3) were the highest seen in 6 years of monitoring at this site. During this period, the concentrations of SO 2 at Meadview were also abnormally high and approximately three times the sulfate concentrations, on a nmol/m 3 basis. High concentrations of sulfate and SO 2 extended south into southern Arizona and northwestern Mexico. Based on ambient atmospheric conditions, emissions from the Mohave Power Project (MPP) 110 km upwind of Meadview could not have been responsible for the majority of the regionally observed sulfur oxides. The geographical distribution of SO 2 and sulfate, and available source information suggest that northwestern Mexico was a significant source of the unusually high observed sulfur oxides. A CMB model developed during Project MOHAVE was used to apportion sulfur oxides at Meadview and other sampling sites throughout the study region for August 31–September 2, 1992. The results indicate that the contribution of MPP to sulfate at Meadview was typical. However, the transport of SO x from northwestern Mexico was elevated throughout much of the region during this time period. This led to the large increase in sulfate concentrations at Meadview on September 1 and 2. These results indicate that emissions from Mexico can be a significant source of particulate material in the Grand Canyon.

Uncertainties in global terrestrial biosphere modeling, Part II: Global constraints for a process‐based vegetation model

The terrestrial biosphere is one of several key components of the global carbon cycle. Because the mechanisms by which climate determines terrestrial biosphere carbon fluxes are not well understood, significant uncertainties concerning model results exist even for the current state of the system, with important consequences for our ability to predict changes under future climate change scenarios. We assess how far this uncertainty can be reduced by constraining a global mechanistic model of vegetation activity, either with global satellite‐derived vegetation index data or with measurements of the seasonal CO2 cycle in the atmosphere. We first show how constraining the model with satellite data from the National Oceanic and Atmospheric Administration advanced very high resolution radiometer reduces the sensitivity to estimated uncertainties in model parameters, and thus the estimated error range of net primary productivity. Regionally, the satellite data deliver the largest constraint for vegetation activity in boreal and arctic as well as in tropical water‐limited environments. In a second analysis through an atmospheric tracer transport model, we check the consistency of those results with the measured seasonal cycle of CO2 at various remote monitoring sites. While before including the satellite data into model calculations, some simulations within the error range lead to a CO2 seasonal cycle outside the observations, there is a good agreement with the additional constraint. The conclusion is that the constraint delivered by the satellite data is at least as significant as that delivered by atmospheric CO2 measurements. We also show that the CO2 data mainly reflect the activity of northern vegetation, in particular conifers and C3 grasses. This suggests that satellite measurements provide the most useful global data currently available for checking and improving terrestrial vegetation models and that consistency with CO2 measurements is a necessary but not a sufficient requirement for their realism.

Noise and vibration control for the Los Angeles Metro Rail Construction Project

Parsons Engineering Science has been retained by the Los Angeles Metropolitan Transportation Authority as the noise and vibration consultant for construction of the 17-mile-long Metro Rail subway system for a period of more than 10 years. Throughout various construction phases, short-term and long-term noise and vibration monitoring have been conducted at sensitive receptor sites such as residences, schools, hospitals, recording studios, businesses, historic buildings, and hotels, to measure both background and construction activities. Continuous noise and vibration data are collected remotely over a computer terminal, such that levels can be monitored on a moment’s notice; our engineers can hear the actual sounds at the remote monitoring site from the office (15–20 miles away), and simultaneously receive decibel levels reported in real-time. Studies are conducted to determine the impacts of various construction activities, such as pile installation, and analyze the feasibility of various construction methodologies based on project noise and vibration compatibility criteria. Mitigation measures are developed to reduce impacts. Examples of mitigation measures included the use of noise curtain walls, noise equipment specifications, selection of construction methodologies, and various acoustical treatments for noise sources. Through the monitoring program and numerous studies, noise and vibration impacts have been successfully minimized.

Modeling Pollutant Transport during High-Ozone Episodes in the Southern Appalachian Mountains

Abstract Airflow patterns and pollution transport in the southern Appalachian Mountains region of the southeastern United States are examined using mesoscale meteorological models and a Lagrangian particle dispersion model (LPDM). The two primary goals of this work are 1) to identify a meteorological modeling methodology that can be used in regional photochemical modeling, and 2) to identify large regional ozone precursor sources that may impact the southern Appalachians during periods having high ozone levels. Four episodes characterized by measured high levels of ozone (1-h average concentrations greater than 90 ppb) at remote monitoring sites are the focus of the modeling efforts. To address the first goal, several methods of airflow modeling involving varying degrees of complexity are examined to find one that reliably simulates the complex wind patterns that occur. A hydrostatic model with homogeneous initialization, a nonhydrostatic model with homogeneous initialization, and a nonhydrostatic model w...

Operational assessment of a potentiometric eight‐sensor flow cell in a portable flow injection analyzer

The evaluation of a novel eight-sensor flow cell used in a portable battery-powered flow injection potentiometry system is described. The portable flow injection system is small in size, light weight, requires low power, and uses a notebook computer for real-time display of data and data acquisition, making it practical for remote site monitoring. The electrode response for each sensor was evaluated in terms of flow rate and injection sample volume with silver and iodide standard solutions, each in a 0.1-M sodium acetate background. The mean electrode slopes observed for silver and iodide ions were 57.4 ± 1.0 and 47.5 ± 4.4 mV per activity decade, respectively. Potential applications include multiion capability with eight different liquid-membrane-based electrodes or operation of the measuring electrodes in an additive mode for improved sensitivity and detection limit for a single analyte. © 1996 John Wiley & Sons, Inc.

Operational assessment of a potentiometric eight-sensor flow cell in a portable flow injection analyzer

The evaluation of a novel eight-sensor flow cell used in a portable battery-powered flow injection potentiometry system is described. The portable flow injection system is small in size, light weight, requires low power, and uses a notebook computer for real-time display of data and data acquisition, making it practical for remote site monitoring. The electrode response for each sensor was evaluated in terms of flow rate and injection sample volume with silver and iodide standard solutions, each in a 0.1-M sodium acetate background. The mean electrode slopes observed for silver and iodide ions were 57.4 ± 1.0 and 47.5 ± 4.4 mV per activity decade, respectively. Potential applications include multiion capability with eight different liquid-membrane-based electrodes or operation of the measuring electrodes in an additive mode for improved sensitivity and detection limit for a single analyte. © 1996 John Wiley & Sons, Inc.

A portable flow injection analyzer for use with ion‐selective electrodes

AbstractA battery powered portable monitor based on flow injection potentiometry has been developed weighing 1.8 kg, constructed in a carry‐case and applicable for remote site monitoring. Portability has been achieved using a light weight rechargeable Ni‐Cd battery‐pack (7.2 V). The flow injection manifold incorporates a low powered peristaltic pump, a wall‐jet type flow cell containing a commercial iodide ion‐selective electrode and a Ag/AgCl reference electrode connected to an analog‐to‐digital converter, also powered by the battery pack, and a RS232‐serial output to a notebook computer for real‐time data display and storage. The system performance has been evaluated using the iodide ion‐selective electrode, including the effects of various carrier solutions on sample peak heights, peak widths and the calibration slopes and working ranges. Fast response with peak widths as low as approximately 10 s. was observed with near Nernstian response of −53.8 mV change per activity decade and a log‐linear range between 5 × 10−6 and 1 × 10−2M in a 0.1 M sodium acetate carrier stream.

Co-occurrence patterns of gaseous air pollutant pairs at different minimum concentrations in the United States

The frequency of co-occurrences for SO 2NO 2, SO 2/O 3 and O 3/NO 2 at rural and remote monitoring sites in the United States was characterized for the months of May-September for the years 1978–1982. Minimum hourly concentrations of 0.03 and 0.05 ppm of each gas were used as the criteria for defining a ‘co-occurrence’. The objectives of this study were to: 1. (1) identify the types of co-occurrence patterns and their frequency; 2. (2) identify whether the frequency of hourly simultaneous co-occurrences increased substantially when the minimum concentration was lowered (e.g. from 0.05 to 0.03 ppm) for each pollutant; and 3. (3) determine whether the frequency of co-occurrences showed large year-to-year variation. For all pollutant pairs and co-occurrence thresholds (i.e. 0.03 and 0.05 ppm), the frequency of daily and hourly co-occurrences was low for most sites. Year-to-year variability was found to be insignificant; most of the monitoring sites experienced co-occurrences of any type less than 12% of the 153 days. Based on our observations, researchers attempting to assess the potential effects of SO 2/NO 2, SO 2/O 3 and O 3/NO 2 in the United States should construct simulated exposure regimes so that 1. (1) hourly simultaneous and daily simultaneous-only co-occurrences are fairly rare and 2. (2) when co-occurrences are present, complex-sequential and sequential-only co-occurrence patterns predominate.