Both research and technological development in the area of renewable energy sources are necessary to account for the increase in energy demand and environment problems in the world. The photovoltaic (PV) cell has been described by non-linear outputs characteristics in current-voltage and power-voltage. This outputs is affected by various effects such as; series resistance ( ), shunt resistance ( ℎ ), solar irradiance and temperature. In this paper the effect of variation of parameters has been studied such as series resistance ( ) and shunt resistance ( ℎ ) of the diode in the photovoltaic cell and these effects could be seen in the Current-Voltage (I-V) and Power-Voltage (P-V) characteristic curves. In this paper also has been studied the effect of variation of the environmental parameters such as solar irradiance and temperature. Results show that a higher temperature at constant solar irradiance produces a decrease power. So the voltage and the photovoltaic cell output power tend to decrease at higher temperatures, but there is no noticeable effect on the photovoltaic cell current. Thus, it is important to keep the cell temperature as low as possible, because higher temperatures have negative effect on output power of photovoltaic cell. On the other hand, the effect of solar irradiance on photovoltaic cell, it reveals that higher solar irradiance gives higher current and higher power. Shunt resistance has significant effect on the operating characteristic curves of PV cells as low power output is recorded if the value of shunt resistance varies from 0.07 ohms to 1700 ohms. Finally, I have presented power-voltage characteristic curves and current voltage characteristic curves of photovoltaic cell for different solar irradiance in Shkoder, Tirana and Vlore.

Due to urbanization trend in Durres city, distance between city inhabitants and nature is increasing. Urban greenery is one of the methods to bridge this gap between people and nature. The study results were performed with the cooperation of EPER Center, professors and students of Durres “Aleksander Moisiu” University. It was focused in the estimation of O2 release from green surfaces at different areas of Durres city. The results achieved were carried out by field visits, the use of the GIS method and calculations performed based on various standard manuals. According to the results, it was concluded that the total amount of O2 release from green surfaces was 64420 kg/year or 64.4 t /year. It was also calculated that the available green surface for a resident in Durres city is only 1.05 m2 out of required 9 m2 per capita. Based on the needs of the population and the EU standards, this study suggests that the amount of O2 release should be 1.49∙ 108 kg/year or 1.49. 5∙ 105 t/year. The needed costs to be invested to achieve this O2 amount, is about 47 .65 billion ALL. Finally, it can be concluded that the low number of trees in Durres city, requires urgent provisions to improve air, and life quality of Durres citizens.

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The presence of pathogenic microbes in food is a serious global problem. Irradiation, as an effective method, destroy pathogens reducing threat that come by uncontrolled food. In this paper we have treated irradiation of animal foods and its effect, to decrease total microbial load on them. Foods were irradiated with a gamma irradiator GU-3 (Cs-137 source) with the rotation technique. Uniformity dose rate used was 106 % and average dose rate 4.68 Gy/min. According to standards, doses used to irradiate food varied from 0 to 5 kGy. From experimental results it was observed that with increasing absorbed dose, total microbial load was reduced with some orders. Variation of log N / N0 (N-total microbial load of irradiated food and N0 of non-irradiated food) with dose, was approximated linearly. Based on this variation was defined D10, as the dose that cause "death" of about 90 % of microbes in food (log N/N0= -1). D values found experimentally had a good correspondence with them defined theoretically (D10 = |1 / slope|).

In recent years the urban population in Durres city has grown ex­ponentially, leading to an increase of CO2 and consequently contributing on a large scale to climate change. Urban trees are basic to sequester CO2 emis­sions as they incorporate carbon in their biomass. The amount of C02 se­questration from green surfaces in Durres city was 50.13 ∙ 106 kg/year instead of 116.35 ∙ 106 kg/year that it should be. Increasing the amount of green veg­etation, the energy that can be stored will be 3.7 ∙ 105 MWh compared with the actual value of 162,48 MWh. Consequently, water carrying capacity will be 2321 times more than the amount of water needed to maintain the pres­ent public green spaces. These data can be used to help assess the actual and potential role of green trees in reducing atmospheric CO2, a dominant greenhouse gas. This study was conducted under the project “Green lungs for our cities - Alternative and comprehensive platform for monitoring air quality, noise pollution and urban greenery to affect policies at the local level”. Measurements were performed with the cooperation of Eper Center, professors and students of “Aleksander Moisiu” University.