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Kabashi Q.,University of Mitrovica | Limani M.,University of Prishtina | Caka N.,University of Prishtina | Zabeli M.,University of Mitrovica
Turkish Journal of Electrical Engineering and Computer Sciences | Year: 2017

Nowadays, variable speed AC motors are widely used in industry and there are many speed adjustment techniques available. In the last decade there has been a trend towards the use of space vector PWM- IGBT inverters, due to easier digital realization and better utilization of the DC bus. Every power inverter produces a total harmonic distortion (THD) on its output that causes extra losses in stator of induction motors. By eliminating a number of low order voltage/current harmonics it is possible to reduce harmonic losses (stator losses) and mechanical oscillations in general. This could be achieved by implementing filters in the output of inverters or by applying a modern modulation technique such as space vector pulse width modulation (SV-PWM). The objective of this paper is focused on using general techniques of SV-PWM in 2-level 3-phase voltage source inverters for inductive load tempting to eliminate the low order voltage/current harmonics, by varying sampling frequency and amplitude modulation index, without using filters. © TÜBITAK.


Peci N.,University of Mitrovica | Elezaj Z.,University of Mitrovica | Krasniqi R.,Independent Commission for Mines and Minerals ICMM | Sinani B.,Independent Commission for Mines and Minerals ICMM | Berisha S.,Exploration geologist
International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM | Year: 2014

The studies presented in this paper dealing with trace metals in stream sediments and are intended to selecting promising areas in which to prospect for metalliferous ore bodies. Geochemical exploration for ore deposits and metalliferous regions is based on the concept that the products of weathering and erosion of rocks are mainly distributed in local soils, plants and stream sediments.Results of stream sediment geochemical analysis were taken by the Independent Commission for Mines and Minerals (ICMM) and comprise entire territory of Kosovo. Within the surveyed area a total of 3240 samples of stream sediment were collected and analyzed. In this paper are taken in consideration results for the trace metals lead, zinc, copper, nickel, chromium and cobalt.The concept of a geochemical anomaly as a concentration level above some arbitrarily chosen background or "threshold" value for a particular element cannot be applied rigorously to regional variations over a large area encompassing different geologic regions with widely different rock types. Consequently, we adopted the procedure of determining the frequency distribution for each trace metal and of defining anomalies in terms of the statistics.The geochemical results were explored using a range of common statistical techniques including descriptive summary statistics, statistical distribution and correlation analysis for selected trace metals. Statistical analysis and interpretation the geochemical results from stream sediment sampling for trace metals lead (Pb), zinc (Zn), copper (Cu), chromium (Cr), nickel (Ni) and Cobalt (Co) indicates that there are potential areas for increased exploration on these metals. It is recommended to continue the presented investigations by verification activities including mapping, litho-geochemistry, trenching, drilling. © SGEM2014. All Rights Reserved.


Malollari I.,University of Tirana | Kotori P.,University of Vlora | Hoxha P.,Polytechnic University of Tirana | Lici L.,Polytechnic University of Tirana | And 4 more authors.
Journal of Environmental Protection and Ecology | Year: 2016

In Albania has already grown a big ambition for mushroom production and it is reasonable to study the effect of residues coming from this activity and finding the proper way to profit useful components. For every kilogram (kg) of mushroom produced, about 5 kg of SMS is generated and, traditionally, has been discarded as waste. The fast increase in mushroom production worldwide has resulted in large quantities of SMS. These great amounts of waste can cause environmental problems, which has led to increased research to develop technologies for treating wasted spent mushroom. Spent mushroom substrate (SMS) is the substrate left over after mushroom harvesting.


Baruti B.,University of Mitrovica | Malollari I.,University of Tirana | Lajci N.,University of Mitrovica | Sadiku M.,University of Mitrovica | And 4 more authors.
Journal of Environmental Protection and Ecology | Year: 2014

Noise, commonly defined as an unwanted sound, is an environmental phenomenon to which human are exposed throughout their life. Human susceptibility to noise varies in terms of intensity, altitude, timbre of sound, personal sensibility, age, and history of ear disorder. Noise is not simply an annoyance rather a hazard to one's physical and mental well-being. For this reason, studies were carried out for the determination of noise levels at hotels and living there by in the Mitrovica city. Noise levels have been measured at 13 hotels by the sound level meter of Type IEC 651 with the maximum 130 dB. Results reveal that the level of noise at hotels exceeds the allowable limit to a great extent. Therefore, the present status of noise pollution at the hotels in Mitrovica poses a severe health risk to the residents.


Baruti B.,University of Mitrovica | Malollari I.,University of Tirana | Ferati S.,Deputy of the Kosovo Assembly | Lajci N.,University of Mitrovica | And 4 more authors.
Journal of Environmental Protection and Ecology | Year: 2014

The raw material used for the production of electricity at Kosova Thermal Power Plants is coal. These plants use large quantities of water and have no wastewater treatment. Working activity in these plants results in water pollution which after discharge into water causes environmental impact. Polluted water discharged from these plants into the Sitnica river results in pollution with significant impact on local and regional level. The discharge of polluted water from coal mines, thermal power plants and existing ash landfills is a result of disregarding the environmental legislation. The obtained results from the samples taken at different locations before they discharge into the Sitnica river revealed that they are polluted in quality aspect from mines and in quantity aspect from power plants. Advanced wastewater treatments such as classification, treatment, flocculation and filtration of the discharged waters would enable their re-use and minimisation the pollution of the river Sitnica which further discharged into the Iber river.


Ferati F.,University of Mitrovica | Kerolli-Mustafa M.,International Business College Mitrovica | Kraja-Ylli A.,University of Tirana
Environmental Monitoring and Assessment | Year: 2015

The concentrations of As, Cd, Cr, Co, Cu, Ni, Pb, and Zn in water and sediment samples from Trepça and Sitnica rivers were determined to assess the level of contamination. Six water and sediment samples were collected during the period from April to July 2014. Most of the water samples was found within the European and Kosovo permissible limits. The highest concentration of As, Cd, Pb, and Zn originates primarily from anthropogenic sources such discharge of industrial water from mining flotation and from the mine waste eroded from the river banks. Sediment contamination assessment was carried out using the pollution indicators such as contamination factor (CF), degree of contamination (Cd), modified degree of contamination (mCd), pollution load index (PLI), and geo-accumulation index (Igeo). The CF values for the investigated metals indicated a high contaminated nature of sediments, while the Cd values indicated a very high contamination degree of sediments. The mCd values indicate a high degree of contamination of Sitnica river sediment to ultrahigh degree of contamination of Trepça river sediment. The PLI values ranged from 1.89 to 14.1 which indicate that the heavy metal concentration levels in all investigated sites exceeded the background values and sediment quality guidelines. The average values of Igeo revealed the following ranking of intensity of heavy metal contamination of the Trepça and Sitnica river sediments: Cd > As > Pb > Zn > Cu > Co > Cr > Ni. Cluster analysis suggests that As, Cd, Cr, Co, Cu, Ni, Pb, and Zn are derived from anthropogenic sources, particularly discharges from mining flotation and erosion form waste from a zinc mine plant. In order to protect the sediments from further contamination, the designing of a monitoring network and reducing the anthropogenic discharges are suggested. © 2015, Springer International Publishing Switzerland.


This work reports the synthesis of some new derivatives from 4-Chloro-chromen-2-one and describe the results of antibacterial activity of purified compounds. Compounds 4-Butylamino-chromen-2-one (1a) , 4-Butylamino-2-oxo-2H-chromene-3-sulfonyl chloride (2a) , 4-Butylamino-2-oxo-2H-chromene-3-sulfonic acid (2-hydroxy-phenyl)-amide (3a), 4-Butylamino-5-ethyl-2-oxo-7-(N′-phenyl-hydrazino)-2H-chromene-3-sulfonic acid (2-hydroxy-phenyl)-amide (4a), have been synthesized and characterized using melting points, IR spectra, 1H-NMR and 13C-NMR spectra. The antibacterial activity of synthesized compounds and streptomycin at concentractions of 1mg/ml, 3mg/ml and 5mg/ml, have been evaluated against three strains of bacterial culture; Staphylococcus aureus, E.coli and Klebsiella. The compounds show bacteriostatic and bactericidal activity. © 2014, Oriental Scientific Publishing Company. All rights reserved.

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