Volume 20 - 2018

Wind energy is a resource that does not require any fuel or feedstock to be treated, refined or transported. It does not produce air pollution and hazardous waste. Because of these, wind energy, one of the major renewable energy sources, has been widely used in recent years. In this work, a three-phase distribution static synchronous compensator (D-STATCOM) is demonstrated for power quality enhancement in wind energy distribution systems. A five-level cascaded inverter is used to implement the D-STATCOM. D-STATCOM is controlled to compensate the reactive power, balances the load and eliminate harmonics. A novel control algorithm is based on the indirect current control system with synchronous reference frame theory for generating the gating pulses of Voltage Source Inverter (VSI). This proposed control system has one model predictive controller and two modified fuzzy logic controllers. The performance of the three-phase D-STATCOM is validated for power quality enhancement with different loads through software implementation using Matlab/Simulink environment. The effectiveness of the proposed approach is verified through simulation studies.

Sediments play an important role in the quality of aquatic ecosystems in the Dam Lake where they can either be a sink or a source of contaminants, depending on the management. This purpose of this study is to identify the sediment quality in order to find out the causes for the malodor and the eutrophication that is causing a bad scenario. Solutions for improving the dam are proposed. Multivariate statistical techniques, such as a principal component analysis (PCA) and cluster analysis (CA), were applied to the data regarding sediment quality in relation to anthropogenic impact in Suat Ugurlu Dam Lake. This data was generated during 2014-2015, with monitoring at four sites for 11 parameters. A PCA and CA were used in the study of the samples. The total variance of 84.1%, 74.3%, 87.4% and 91.5% suggest 4, 3, 3 and 4 principle components (PCs) in the four locations: LC1, LC2, LC3 and LC4, respectively. Also, a CA was applied to both the variables and the observations. Some variables and observations showed a high similarity based on the results of variables in the CA. Also, the similarity ratio of temperature-mercury (Hg) and oxidation reduction potential (ORP) was high and generally, the cluster number of variables was 5, according to the selected similarity level.

Coastal management is generally means planning and application of environmental changes in the coastal area. The rapid spread of industrialization, urbanization, tourism and recreational activities are affecting the coastal cities in a much more negative way in Turkey, compared to other countries. Development in infrastructure to meet the needs of the population growing in coastal areas, provision of industrial and tourism facilities or power plants, placement of main roads in the coastal zone, separation of forest areas for secondary residences or workplaces are the most important factors leading to the deterioration of the identity of coastal cities. In this study, the changes of the coastal areas in Ordu Province, one of the important touristic cities of the Black Sea Region, have been examined and evaluated. Moreover, present shoreline was investigated within the framework of Turkish Coastal Law. Finally, the variation of coastal area was determined by using the ArcMap module of ArcGIS 10 programme as numerical. The results showed that the coastal area significantly increased by filling during a short period.

The determination of organotin compounds (OTCs) in environmental matrices has been subject to great scientific attention during last years, as the accuracy and sensitivity of analytical methods need to be improved in order to be able to detect the compounds of interest in a complex matrix such as sediment. The European Union Water Framework Directive (2013/39/EU) sets very restrictive environmental quality standards for 45 priority substances and other pollutants, including OTCs. Therefore, it is necessary to develop analytical methods in compliance with the environmental quality standard (EQSs) proposed to protect the aquatic environment and human beings. So far various analytical procedures have been used, including gas chromatographic analyses. Most of these methods comprise different steps such as extraction, derivatisation, clean up and the use of several sophisticated instrumentations, as well. Among them the conversion of tributyltin into Sn to allow its determination by Atomic Absorption Spectrometry or Anodic Stripping Voltammetry (AVS) has also been attempted. A great number of studies have been performed on OTCs analysis in marine sediment. However, the only review available in literature discussing the upgrades of analytical methods is dated back to 1997. We reviewed the analytical procedures and discussed them comparatively in order to identify the current state-of-the-art in OTCs detection. Finally, environmental concerns about OTCs were discussed.