STATE OF THE ART OF SMALL WIND ENERGY ANALYSING DIFFERENT CONTROLS

There are two wind turbine topologies according to the axis of rotation: horizontal axis, "Horizontal Axis Wind Turbines" (HAWT) and vertical axis, "Vertical Axis Wind Turbines" (VAWT) [2]. HAWT turbines are used for high power generation as they have a higher energy conversion efficiency [2]. However, VAWTs are used in mini wind applications because they do not need to be oriented to the prevailing wind and have lower installation cost.

Investigating natural cooling of piled sugar beet

The paper examines the processes of natural cooling of a medium-storage pile containing 3,650 tons of sugar beets. Adiabatic cooling and related processes are established to have a predominant effect on reducing the temperature in the pile while in storage. Piled sugar beet is cooled due to some natural water evaporation from the surface of sugar beets, followed by moisture saturation of the outside air. Such cooling leads to an uncontrolled decrease in the quality of beets, which has negative implications during further processing. A formula is presented for calculating post-harvest yield loss in sugar beets piled with one slope being across the prevailing wind.

Assessment of Natural Radioactivity, Heavy Metals and Partic-Ulate Matter in Air and Soil Around a Coal-Fired Power Plant—An Integrated Approach

A comprehensive study of the environmental radioactivity covered in a distance up to 20 km from a point source—two stacks of a coal-fired power plant. Airborne particulate matter was collected, and the element composition on the 30 cm soil profile was determined. The range of activity concentrations of 226Ra, 232Th and 40K from the studied areas varies from 8 Bq/kg to 41 Bq/kg, 5 to 72 Bq/kg and 62 to 795 Bq/kg, respectively. The activities values are increased by 44% for 226Ra, 37% for 40K, and 75% for 232Th in the prevailing wind direction. For some elements, the respective concentration in the soil is above the maximum permissible level for all types of soil use, particularly for the arsenic concentration. The deposition flux ranged from 0.36 to 5.70 (g m−2 per month) in the first sampling campaign and from 0.02 to 3.10 (g m−2 per month) for the second sampling campaign. Maps on the spatial distribution of gamma dose rates, radionuclides activity concentrations, deposition flux and trace metals in topsoil were developed for the study region. These maps are in accordance with higher values in specific locations in the vicinity of the coal-fired power plant, showing the influence of point sources, and for locations within 6 and 20 km from the stacks, particularly in the prevailing wind direction.

The Potential of Native Plants for Phytoextraction in Phytoremediation of Lead and Nickel from the Soil of Mohammadabad Qazvin Landfill

Background: Heavy metals are dangerous environmental pollutants that cause health hazards to humans, plants, and other living organisms by entering the food chain. Objectives: This research was carried out around Mohammadabad Qazvin landfill with the aim of measuring the concentration of lead and nickel metals in three plant species, including Artemisia sieberi, Salsola orientalis, and Halimocnemis pilifera, as well as the soil of the region. Methods: In order to study three plots of 50 × 50 meters with distances of 500 meters from each other in the direction of the prevailing wind in the area, sampling of soil, roots, and aerial organs of plant species was performed. After preparing the samples, the concentrations of lead and nickel metals were measured using an atomic absorption spectrometer. Results: The results showed that the soil of the three plots did not differ significantly in terms of the concentrations of lead and nickel. Also, there was no significant difference between the aerial organs and roots of the studied species in terms of the concentration of these elements. This difference was statistically significant only in H. pilifera in terms of nickel concentration at the level of 5%. Conclusions: Considering the factors of accumulation and transportation of lead and nickel metals in the studied plants, it can be suggested that H. pilifera and A. sieberi species are suitable for remediation of lead metal from contaminated soils, while none of these species are suitable for nickel phytoremediation.

The Occurrences and Formation of Ladderback Ripples on Barchans Dunes of Najaf Dunes Field, Iraq, in Aeolian Environments

This paper concerns the study of ripples that occur on the windward of Barchan dunes from the dunes field of Najaf governorate, Iraq. These dunes consist mainly of sand sediments with variable sizes, including medium, fine, and very fine sands. Quartz represents the major light mineral in the Najaf Dunes sand. The prevailing wind direction in the study area is NW-SE. The major ripple crest series of every pattern are oriented perpendicular to the NW-SE wind direction, whereas imbricated ripple groups within the troughs of the preexisting ripples are created by the WSW-ENE wind trend. These ripples tend to be formed by shortened ripples that occupy the troughs of the prolonged series. All crests of the ladderback ripples are oriented at right angles to asymmetry ripples. The ladderback ripples were noticed from fine to very fine- grained sediments, which consist mainly of quartz. The wavelength of the ladderback ripples ranges from 2 – 4 cm, while they are 0.1 – 0.2 cm in height. The occurrence of ladderback ripples within an aeolian environment indicates a variety of wind directions, which influenced the arrangements of the crest ripples.

Seasonal dynamics of snow ablation on selected glaciers in central Spitsbergen derived from Sentinel-2 satellite images

The dynamics of seasonal snow ablation on six glaciers in central Spitsbergen (Dicksonland) were assessed by examining a set of Sentinel-2 satellite images covering the summer ablation season for the period 2016–19. All glaciers lost 80% or more of their surface snow cover during the studied ablation seasons. This bolsters the recently observed trend of local glacier thinning, even at higher altitudes. Snow ablation dynamics are highly dependent on the glaciers altitudes, their position relative to the prevailing wind direction and the exposure to insolation. The accumulation areas of the studied glaciers were delimited based on the overlap of the minimum extent of snow-covered areas in the four consecutive studied summer seasons. The high temporal and spatial resolutions of available images enabled a detailed description of the seasonal snow ablation dynamics. Moreover, an estimate of the average number of days with below threshold glacier snow cover was made. This study contributes to our understanding of recent processes and might further support the modelling of glacier melt and subsequent runoff.

Flight Data-Based Wind Disturbance and Air Data Estimation

The instantaneous wind field and air data, including true airspeed, angle of attack, angle of sideslip, cannot be measured and recorded accurately in wind disturbance. A new air data and wind field estimation method is proposed based on flight data in this study. Since the wind field is the horizontal prevailing wind added by turbulence, the slowly time-varying prevailing wind and small-scale turbulence are described by the exponentially correlated stochastic wind model and von Karman turbulence model, respectively. The system update equation of air data is built based on inertial measurements instead of the complex aerodynamic and aero-engine model of aircraft. Benefitted by the post-analysis characteristics of flight data, a forward–backward filtering algorithm was designed to improve the estimation accuracy. Simulation results indicate that the forward–backward filter integrated with the von Karman turbulence model can reduce the estimation error and ensure filtering stability. A further test with actual flight data shows that the forward–backward filter is not only able to track the wide-range change in prevailing wind but also reduce the adverse effects of uncertain disturbance on estimation accuracy.

Estimating gaseous pollutants in the air near Daura Refinery, Daura Power Plant and South of Baghdad Power Plant by calculating the fuel discharge

This study addresses estimation of emission rates and concentrations of SO2, CO and NO2 gases emitted from Daura Refinery (DR), Daura Power Plant (DPP) and South of Baghdad Power Plant (SBPP) by calculating the fuel discharge. The estimations were made by using the Gaussian plume model of dispersion at distances within 10 km from the pollution source for January, April, July and October 2017 under two stability conditions, slightly stable and moderately unstable. The effect of wind speed and direction as well as the ambient temperature of the surrounding air on the dispersion and transmission of air pollutants were also investigated. It was found that the unstable conditions are better for dispersing out atmospheric pollutants. The results showed that Zafarania District was the most affected by pollutants emitted from DR and BSPP while Daura District was more affected by DPP due to the prevailing wind direction. It was also found that an increase in wind speed leads to a decrease in the concentration of pollutants. The concentration of pollutants is inversely proportional to the height of the chimney, the speed of the gas leaving the chimney, while it is directly proportional to the diameter of the chimney. DPP has higher emission rates than DR and SBPP while at the surface level, the pollutants concentrations emitted from DR are greater than those emitted from DPP and SBPP.