scholarly journals Measurements of RF Radiation in the Vicinity of FM and TV Broadcasting Stations

2001 ◽  
Vol 6 (1) ◽  
pp. 45
Author(s):  
Abdulaziz S. Al-Ruwais
Keyword(s):  
Power Density ◽  
Ground Level ◽  
Above Ground Level ◽  
Average Value ◽  
Broadcasting Station ◽  
Measured Power ◽  
Tv Broadcasting

This paper provides measurements of power density around an FM and VHF-TV broadcasting station and its variation with distance.  The maximum measured value was about 2.4 mW/cm2 at a height of 2 meters above ground level while the average value was fluctuating around 1 mW/cm2.  It was found that the measured power density increases with height above ground and it reaches about 3.5 mW/cm2 at a height of about 15 meters at a location of about 400 meters from the station.  At a nearer distance of 185 meters from the tower another measurement was taken at a height of 18 meters, the power density increased to 41 mW/cm2.  

scholarly journals Wind energy resource assessment for Suva, Fiji, with accurate Weibull parameters

2019 ◽  
Vol 37 (3) ◽  
pp. 1009-1038 ◽  
Author(s):  
Saiyad S Kutty ◽  
MGM Khan ◽  
M Rafiuddin Ahmed
Keyword(s):  
Wind Speed ◽  
Wind Power ◽  
Power Density ◽  
Energy Production ◽  
Ground Level ◽  
Resource Assessment ◽  
Above Ground Level ◽  
Application Program ◽  
Wind Power Density ◽  
Wind Speeds

Wind resource assessment is carried out for Suva, the capital of the Republic of Fiji Islands. The wind speeds at 34 m and 20 m above ground level, wind direction, atmospheric pressure, and temperature were measured for more than five years and were statistically analyzed. The daily, monthly, yearly, and seasonal averages were estimated. For the site, the overall average wind speed at 34 m above ground level is found to be 5.18 m/s. The occurrence of effective wind (between the cut-in and cut-off wind speeds of the selected turbine) is predominantly from the east. An effective wind speed of 74.175% was recorded which can be used for power generation. The turbulence intensity and wind shear coefficient are estimated. The site’s overall turbulence intensities are 12.5% and 13.72% at 34 m and 20 m above ground level, respectively. The diurnal wind shear correlated with the temperature variation very well. The overall and seasonal wind distributions are analyzed, which shows that the wind speed in Suva is mostly between 3 m/s and 9 m/s although the winter season has higher wind speeds. The Weibull parameters and the wind power density were found using 10 different methods. The wind power density is estimated to be 159 W/m2 using the best method, which is found to be the empirical method of Justus. A high-resolution map around the site is digitized and the wind power density resource map is generated using wind atlas analysis and application program. From the wind atlas analysis and application program analysis, it is seen that Suva has high potential for power generation. Five possible locations are selected for installing wind turbines and the annual energy production is estimated using wind atlas analysis and application program. The total annual energy production from the five sites is 1950 MWh. The average capacity factor of the five turbines is 17%. An economic analysis is performed which showed a payback period of 10.83 years.

scholarly journals Assessment of wind energy potential for Tuvalu with accurate estimation of Weibull parameters

2020 ◽  
Vol 38 (5) ◽  
pp. 1742-1773
Author(s):  
Fatonga Talama ◽  
Saiyad S Kutty ◽  
Ajal Kumar ◽  
MGM Khan ◽  
M Rafiuddin Ahmed
Keyword(s):  
Maximum Likelihood ◽  
Wind Power ◽  
Power Density ◽  
Maximum Likelihood Method ◽  
Ground Level ◽  
Empirical Method ◽  
Likelihood Method ◽  
Above Ground Level ◽  
Wind Speeds ◽  
Wind Resource

Wind resource assessments are carried out for two sites in Tuvalu: Funafuti and Nukufetau. The wind speeds at 34 and 20 m above ground level were recorded for approximately 12 months and analyzed. The averages of each site are computed as the overall, daily, monthly, annual, and seasonal averages. The overall average wind speeds for Funafuti and Nukufetau at 34 m above ground level were estimated to be 6.19 and 5.36 m/s, respectively. The turbulence intensities at the two sites were also analyzed. The turbulence intensity is also computed for windy and low-wind days. Wind shear analysis was carried out and correlated with temperature variation. Ten different methods: median and quartiles method, the empirical method of Lysen, the empirical method of Justus, the moments method, the least squares method, the maximum likelihood method, the modified maximum likelihood method, the energy pattern factor method, method of multi-objective moments, and the wind atlas analysis and application program method were used to find the Weibull parameters. From these methods, the best method is used to determine the wind power density for the site. The wind power density for Funafuti is 228.18 W/m2 and for Nukufetau is 145.1 W/m2. The site maps were digitized and with the WAsP software, five potential locations were selected for each site from the wind resource map. The annual energy production for the sites was computed using wind atlas analysis and application program to be 2921.34 and 1848.49 MWh. The payback periods of installing the turbines for each site are calculated by performing an economic analysis, which showed payback periods of between 3.13 and 4.21 years for Funafuti and between 4.83 to 6.72 years for Nukufetau.

scholarly journals Spatial Analysis (Measurements at Heights of 10 m and 20 m above Ground Level) of the Concentrations of Particulate Matter (PM10, PM2.5, and PM1.0) and Gaseous Pollutants (H2S) on the University Campus: A Case Study

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 62
Author(s):  
Robert Cichowicz ◽  
Maciej Dobrzański
Keyword(s):  
Spatial Distribution ◽  
Hydrogen Sulfide ◽  
Particulate Matter ◽  
Air Quality ◽  
Spatial Analysis ◽  
Ground Level ◽  
Leeward Side ◽  
High Concentration ◽  
Above Ground Level ◽  
High Concentrations

Spatial analysis of the distribution of particulate matter PM10, PM2.5, PM1.0, and hydrogen sulfide (H2S) gas pollution was performed in the area around a university library building. The reasons for the subject matter were reports related to the perceptible odor characteristic of hydrogen sulfide and a general poor assessment of air quality by employees and students. Due to the area of analysis, it was decided to perform measurements at two heights, 10 m and 20 m above ground level, using measuring equipment attached to a DJI Matrice 600 unmanned aerial vehicle (UAV). The aim of the measurements was air quality assessment and investigate the convergence of the theory of air flow around the building with the spatial distribution of air pollutants. Considerable differences of up to 63% were observed in the concentrations of pollutants measured around the building, especially between opposite sides, depending on the direction of the wind. To explain these differences, the theory of aerodynamics was applied to visualize the probable airflow in the direction of the wind. A strong convergence was observed between the aerodynamic model and the spatial distribution of pollutants. This was evidenced by the high concentrations of dust in the areas of strong turbulence at the edges of the building and on the leeward side. The accumulation of pollutants was also clearly noticeable in these locations. A high concentration of H2S was recorded around the library building on the side of the car park. On the other hand, the air turbulence around the building dispersed the gas pollution, causing the concentration of H2S to drop on the leeward side. It was confirmed that in some analyzed areas the permissible concentration of H2S was exceeded.

scholarly journals A Climatology of Nocturnal Low-Level Jets at Cabauw

2009 ◽  
Vol 48 (8) ◽  
pp. 1627-1642 ◽  
Author(s):  
P. Baas ◽  
F. C. Bosveld ◽  
H. Klein Baltink ◽  
A. A. M. Holtslag
Keyword(s):  
Wind Speed ◽  
Ground Level ◽  
Geostrophic Wind ◽  
Stable Stratification ◽  
Radiative Cooling ◽  
Inertial Oscillation ◽  
Stable Boundary Layers ◽  
Above Ground Level ◽  
Low Level ◽  
Low Level Jets

Abstract A climatology of nocturnal low-level jets (LLJs) is presented for the topographically flat measurement site at Cabauw, the Netherlands. LLJ characteristics are derived from a 7-yr half-hourly database of wind speed profiles, obtained from the 200-m mast and a wind profiler. Many LLJs at Cabauw originate from an inertial oscillation, which develops after sunset in a layer decoupled from the surface by stable stratification. The data are classified to different types of stable boundary layers by using the geostrophic wind speed and the isothermal net radiative cooling as classification parameters. For each of these classes, LLJ characteristics like frequency of occurrence, height above ground level, and the turning of the wind vector across the boundary layer are determined. It is found that LLJs occur in about 20% of the nights, are typically situated at 140–260 m above ground level, and have a speed of 6–10 m s−1. Development of a substantial LLJ is most likely to occur for moderate geostrophic forcing and a high radiative cooling. A comparison with the 40-yr ECMWF Re-Analysis (ERA-40) is added to illustrate how the results can be used to evaluate the performance of atmospheric models.

scholarly journals Pruning intensity and amino acids tryptophan and glycine on growth and flowering of Jasminum sambac

2021 ◽  
Vol 27 (1) ◽  
pp. 20-25
Author(s):  
Ziyad Khalf Salih ◽  
Seyedeh Somayyeh Shafiei Masouleh ◽  
Mohamed Abdulla Ahmed ◽  
Marwan Abdulla Sanam
Keyword(s):  
Amino Acids ◽  
Essential Oil ◽  
Foliar Application ◽  
Ground Level ◽  
Growth And Yield ◽  
Reproductive Growth ◽  
Above Ground Level ◽  
Evergreen Shrub ◽  
Jasminum Sambac ◽  
Pruning Intensity

Abstract Jasmine (Jasminum sambac L.) is an evergreen shrub and very fragrant, which has a very importance in the perfume industry and its flowers are used in different religious and ceremonies. Training the shrubs for more yields of flowers and essential oil with horticultural improvement effects of pruning and amino acids may help gardeners to achieve more benefits. This study aimed to investigate the effects of pruning intensity (without pruning, 40, 60 or 75 cm above ground level) and foliar application of amino acids (without amino acids, tryptophan or glycine) on jasmine shrubs for promoting growth and reproductive growth and the content of essential oil. The results showed that plants with light pruning (75 cm) and foliar application of amino acids especially glycine had the best growth and yield, which means that plants were affected by the interactions of pruning level and application of amino acids.

scholarly journals Statistical evaluation of ozone concentrations on open plots in a submountain beech ecosystem in the Western Carpathians Mts.

Beskydy ◽  
2013 ◽  
Vol 6 (1) ◽  
pp. 59-66
Author(s):  
Daniela Kellerová ◽  
Rastislav Janík
Keyword(s):  
Forest Cover ◽  
Statistical Evaluation ◽  
Ground Level ◽  
High Variability ◽  
Ground Level Ozone ◽  
Average Value ◽  
Ozone Concentrations ◽  
Carpathian Region ◽  
Beech Stand ◽  
Research Period

The research was conducted on two plots without forest cover situated in the Štiavnické vrchy (A) Mts and in the Kremnické vrchy (B) Mts (Western Carpathian region) and a plot covered with several-year-old naturally regenerated beech stand (C) in the Kremnické vrchy Mts. The highest average value of 71 µg m-3 was recorded in 2007 for all plots; the lowest one was 45 µg m-3 recorded in 2009. Maximum values of ground level ozone concentrations ranging from 124 to 144 µg m-3 were recorded in spring 2008 on all study plots. The values were displaying fairly high variability over the whore research period, with minima in years 2007 and 2008 on the plot covered with forest stand at the time. Statistically significant differences were distinct especially between the years 2007 and 2009.

scholarly journals Development and application of a new mobile LOPAP instrument for the measurement of HONO altitude profiles in the planetary boundary layer

2009 ◽  
Vol 2 (4) ◽  
pp. 2027-2054 ◽  
Author(s):  
R. Häseler ◽  
T. Brauers ◽  
F. Holland ◽  
A. Wahner
Keyword(s):  
Nitrous Acid ◽  
Ground Level ◽  
Concentration Profiles ◽  
Mixing Ratio ◽  
Above Ground Level ◽  
Mixing Ratios ◽  
New Instrument ◽  
Mobile Measurements ◽  
Southwest Germany ◽  
Absorption Technique

Abstract. The LOPAP (long path absorption) technique has been shown to be very sensitive for the detection of nitrous acid (HONO) in the atmosphere. However, current instruments were mainly built for ground based applications. Therefore, we designed a new LOPAP instrument to be more versatile for mobile measurements and to meet the requirements for airborne application. The detection limit of the new instrument is below 1 ppt at a time resolution of 5 to 7 min. As a first test, the instrument was successfully employed during the ZEPTER-1 campaign in July 2007 on board of the Zeppelin NT airship. During 15 flights on six days we measured HONO concentration profiles over southwest Germany, predominantly in the range between 100 m and 650 m above ground level. On average, a mixing ratio of 34 ppt was observed, almost independently of height. Within a econd campaign, ZEPTER-2 in fall 2008, higher HONO mixing ratios were observed in the Lake Constance area.

UAV high-resolution magnetic mapping of the Chenaillet ophiolite, in the Alps

2021 ◽  
Author(s):  
Pauline Le Maire ◽  
Denis Thieblemont ◽  
Marc Munschy ◽  
Guillaume Martelet ◽  
Geoffroy Mohn
Keyword(s):  
Magnetic Field ◽  
Ground Level ◽  
Weather Conditions ◽  
Geological Mapping ◽  
Magnetic Data ◽  
Magnetic Survey ◽  
Magnetic Signal ◽  
Alpine Orogeny ◽  
Above Ground Level ◽  
Slow Spreading

<p>Continent-Ocean Transitions (COT) and ultra-slow spreading ridges, floored by wide area of exhumed serpentinized mantle, bear strong amplitude magnetic lineations. However, whether these anomalies are linked to inversions of the direction of the magnetization (therefore characterized as isochrones of seafloor spreading) or to structural and lithological contrasts remains an open question. Generally, marine magnetic data acquired at sea surface along profiles, are too low resolution to image the intensity variations of the magnetic field at a kilometric scale. Performing a dense deep tow magnetic survey at a present-day COT or ultra-slow spreading system would be better to determine the sources of the magnetic signal but remains expensive. To go ahead, a valuable alternative to address these questions is to record the magnetic signal on ophiolite representing remnants of COT and oceanic systems sampled in orogenic system. We worked on the Chenaillet Ophiolite (French Alps), which represents a fossil COT or ultra-slow spreading system integrated to the Alpine orogeny. This ophiolite escaped high-pressure metamorphism and has only been weakly deformed during Alpine orogeny, preserving its pre-orogenic structure.</p><p>We performed an UAV magnetic survey using fluxgate magnetometers in complex conditions due to the altitude (> 1800 m), the strong topography variations and the weather conditions (negative temperatures, snow). Despite these difficulties, which highlight the viability of UAV for geophysical measurements, a survey of 20 square kilometers with 219 km of profiling was completed 100 m above ground level. Flight line spacing is 100 m above the ophiolitic basement and 200 m above the sedimentary units. Another magnetic UAV survey was flown with another UAV to map a small area 10 m above ground level. Magnetic anomaly maps were computed after standard processing (e.g., calibration/compensation, temporal variation and regional magnetic field corrections, levelling).</p><p>Our first results evidence well-defined magnetic anomalies clearly linked to serpentinite. This shows that the magnetic signal is of sufficient resolution to contribute to a revision of the cartography of the massif combining geological observations and magnetic data.</p><p>In addition, the magnetic susceptibility was measured on 60 outcrops, to support interpretation.</p><p>In this presentation, we focus on the magnetic acquisition campaigns, processing and 2D/3D interpretations by forward modelling and data inversion. Lastly, two items are discussed: 1) contribution of magnetic UAV surveys for geological mapping; and 2) implication of the results on the Chenaillet massif to discuss the contribution of magnetic mapping to the understanding of the TOC or ultra-slow spreading system.</p>

Application of Cellular Communications Models and Designs for Use in Disaster-Aftermath Related Scenarios

2015 ◽  
Vol 7 (3) ◽  
pp. 46-56
Author(s):  
Stephen J. Curran
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Ground Level ◽  
Base Station ◽  
Cellular Communications ◽  
Fixed Position ◽  
Above Ground Level ◽  
High Altitude Platforms ◽  
Major Disaster ◽  
Future Strategy ◽  
Low Altitude

This paper is a pilot study on the concept of an aerial base station as a future strategy for restoring cellular communications in the aftermath of a major disaster. The strategy being studied makes use of low altitude platforms (LAPs) or unmanned aerial vehicles (UAVs) that can hover or orbit in a relatively fixed position and can act as an aerial base station. Unlike High Altitude Platforms (HAP) operating in a layer of the atmosphere above any existing air traffic, the LAPs or UAVs will be able to operate a few hundred to some thousands of meters above ground level. This paper also describes the functionality of the components comprising the aerial base station.

Wind resource assessment and wind farm modeling in Mossobo-Harena area, North Ethiopia

2020 ◽  
pp. 0309524X2092540
Author(s):  
Addisu Dagne Zegeye
Keyword(s):  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Power Density ◽  
Energy Production ◽  
Wind Farm ◽  
Ground Level ◽  
Energy Potential ◽  
Mean Power ◽  
Wind Energy Potential

Although Ethiopia does not have significant fossil fuel resource, it is endowed with a huge amount of renewable energy resources such as hydro, wind, geothermal, and solar power. However, only a small portion of these resources has been utilized so far and less than 30% of the nation’s population has access to electricity. The wind energy potential of the country is estimated to be up to 10 GW. Yet less than 5% of this potential is developed so far. One of the reasons for this low utilization of wind energy in Ethiopia is the absence of a reliable and accurate wind atlas and resource maps. Development of reliable and accurate wind atlas and resource maps helps to identify candidate sites for wind energy applications and facilitates the planning and implementation of wind energy projects. The main purpose of this research is to assess the wind energy potential and model wind farm in the Mossobo-Harena site of North Ethiopia. In this research, wind data collected for 2 years from Mossobo-Harena site meteorological station were analyzed using different statistical software to evaluate the wind energy potential of the area. Average wind speed and power density, distribution of the wind, prevailing direction, turbulence intensity, and wind shear profile of the site were determined. Wind Atlas Analysis and Application Program was used to generate the generalized wind climate of the area and develop resource maps. Wind farm layout and preliminary turbine micro-sitting were done by taking various factors into consideration. The IEC wind turbine class of the site was determined and an appropriate wind turbine for the study area wind climate was selected and the net annual energy production and capacity factor of the wind farm were determined. The measured data analysis conducted indicates that the mean wind speed at 10 and 40 m above the ground level is 5.12 and 6.41 m/s, respectively, at measuring site. The measuring site’s mean power density was determined to be 138.55 and 276.52 W/m2 at 10 and 40 m above the ground level, respectively. The prevailing wind direction in the site is from east to south east where about 60% of the wind was recorded. The resource grid maps developed by Wind Atlas Analysis and Application Program on a 10 km × 10 km area at 50 m above the ground level indicate that the selected study area has a mean wind speed of 5.58 m/s and a mean power density of 146 W/m2. The average turbulence intensity of the site was found to be 0.136 at 40 m which indicates that the site has a moderate turbulence level. According to the resource assessment done, the area is classified as a wind Class IIIB site. A 2-MW rated power ENERCON E-82 E2 wind turbine which is an IEC Class IIB turbine with 82 m rotor diameter and 98 m hub height was selected for estimation of annual energy production on the proposed wind farm. 88 ENERCON E-82 E2 wind turbines were properly sited in the wind farm with recommended spacing between the turbines so as to reduce the wake loss. The rated power of the wind farm is 180.4 MW and the net annual energy production and capacity factor of the proposed wind farm were determined to be 434.315 GWh and 27.48% after considering various losses in the wind farm.

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