Volume 17, Issue 1, Winter 2022, Page 1-29


Comparison of the change in viscosity of a polyvinyl alcohol solution by adding Polyethylene glycol and Polyvinylpyrrolidone to solutions of Polyvinylalcohol

Najla Ali Elgheryani

Kirkuk University Journal-Scientific Studies, 2022, Volume 17, Issue 1, Pages 1-6
DOI: 10.32894/kujss.2022.173409

The aim of this research is to improve the flow properties of polymers, in particular viscosity, by mixing polymers to be use in various fields. Samples prepared by stirring polyvinyl alcohol on fire for half a second in a fixed weight ratio with divergent weight ratios of polyethylene glycol and polyvinylpyrrolidone, both separately. Other samples were prepared in the same way by mixing the three polymers followed by measuring the molecular weight of all the samples.  This method of preparation made the polymers insoluble in water, therefore nitric acid was used to dissolve them. Flow time of the solvent and all solutions were measured, which was used to calculate the viscosities, It has been shown that these viscosities increase with increasing concentrations of polymers in solutions by establishing a positive relationship between them, It was found that the intrinsic viscosity decreases with increasing concentrations after being graphed using intrinsic viscosity calculations from the relationship between specific viscosity and relative viscosity logogram with concentration. These results may be used in industrial medical applications as well as scientific studies.

A review of Peak to Average Power Ratio Reduction Schemes in OFDM Systems

Bana Hassan Shekh Faraj; Abdulrahman Ikram Siddiq

Kirkuk University Journal-Scientific Studies, 2022, Volume 17, Issue 1, Pages 7-15
DOI: 10.32894/kujss.2022.173410

This paper is concerned with the Orthogonal Frequency Division Multiplexing (OFDM) system that is adopted by a wireless communication system for transmitting multicarrier modulated signals simultaneously with robustness against interference and noise facing the system. It presents a significant issue related to the OFDM system known as the raise of Peak to Average Power Ratio (PAPR) that is the high peaks of OFDM signals compared to its average power. Increasing the PAPR yields in the component devices of the OFDM system does not cope with the high peaks resulting in distortion and signal losses. Therefore, the objective of this article is to review different approaches of PAPR reduction techniques and compare them to select the best technique for a particular system. The approaches are mainly of three classifications; distortion, probabilistic, and coding schemes with each including several techniques.

Limnological Study in Upstream and Downstream Degala Basin Water Body within Erbil City-Iraq

Kwestan Hassan Sdiq; Layla Aladdin Mohamed Aladdin; Bakhtyar Abullah Othman; Sewgil Saaduldeen Anwer

Kirkuk University Journal-Scientific Studies, 2022, Volume 17, Issue 1, Pages 16-29
DOI: 10.32894/kujss.2022.131488.1046

The Degala Basin is one of the water reservoirs in the heart of the Degala sub-district, roughly 50 kilometers east of Erbil City. Samples were collected monthly from different sites of Degala Basin during October 2020 to August 2021 to determine physicochemical and biological properties EC, TDS, Chloride, Na, K, Ca hardness, total alkalinity, nitrate, and DO, pH, total hardness, Mg hardness, and Sulfate. The statistical analysis of the data revealed that there were significant differences in physico-chemical parameters between the two sites, with high significant relationships for (EC, TDS, chloride, Na, K, Ca hardness, total alkalinity, nitrate, and DO) and low significant relationships for (pH, total hardness, Mg hardness, and Sulfate) at the (p≤0.05) for all parameters studied different algal species obtained from all sampling sites in Degala basin revealed the presence of a variety of algal species. There is small change in the pH value during the observation period among upstream, basin and downstream. Different genera of algae found in Degala basin.