2024-02

Science journal o university of Zakho (Issue : 1) (Volume : 12)

The current experimental study investigates some aspects of the electrical discharge properties between two planar electrodes. These properties involve the relationships of the minimum sparking potential to the electrode separation, the spark repetition rate, and the distribution of discharge pulse height concerning both the applied voltage and electrode separation. These discharge parameters tend to show nonlinear relationship with both applied voltage and electrode separation.

2024-01

Desalination and Water Treatment (Volume : 317)

The literature on the integration of solar heaters with solar stills has sparked considerable debate regarding whether this combination genuinely enhances distillation efficiency. This paper seeks to shed light on this question by examining the daily freshwater yields and thermal efficiencies of four distinct still-heater configurations, each having a total of one-square-meter solar energy collecting area, over several days. These measurements are then compared with the yields and efficiencies of a one-square-meter simple standalone solar still obtained on the same days. The findings reveal that, despite standalone solar stills demonstrating efficiencies ranging from 35% to 45% on days with total daily solar radiation exceeding 6 kW/m2, none of the four stillheater configurations achieved comparable efficiencies on days with solar radiations below approximately 6.7 kW/m2. Notably, the efficiencies of the standalone still were consistently higher than those of all four configurations on days with solar radiation below 6.7 kW/m2. Furthermore, economic analysis indicates that standalone solar stills are more cost-effective to construct than still-heater systems with equivalent solar radiation collecting areas.

2023-07

International Journal of Renewable Energy Development (Issue : 4) (Volume : 12)

This work presents new results from controlled experiments using well-designed and constructed single-inclination solar stills. The aim of these experiments is to explore methods for enhancing still performance by studying the individual effects of three types of methods. Specifically, the experiments investigate the actual effects of still basin water depth, the use of a sensible heat storage medium, and the treatment of the inner glass surface with waxy substances. The main distinction in this work is the use of solar stills that can achieve thermal efficiencies in excess of 40% under favourable weather conditions without any modification. This high efficiency level allows for meaningful analysis of the impact of modifications on still performance. The results indicate that still yield, productivity, and thermal efficiency decrease significantly when the water depth in the basin exceeds 6 cm. additionally, introducing black gravel in excess of a 2% gravel to water mass ratio in the still basin does not produce a significant change in still thermal efficiency. Treatment of the still inner glass surface with two types of waxy materials resulted in large drop in still performance.

2023-06

Desalination and Water Treatment (Volume : 298)

This study presents an empirical model based on experimental results of a simple single-slope conventional solar still’s daily yield of distilled water, productivity, and thermal efficiency. The model assumes that the still efficiency can be factored as a function of three independent weather parameters beside solar radiation: atmospheric temperature, wind speed, and dew point. The effect of the latter parameter has seldom been studied. Correlation analysis showed that relative humidity and atmospheric pressure are dependent on those three, and their effects on still performance are only signatures of the three independent weather variables. Hence, they are not included in the modeling. The model predicts that temperature, dew point temperature, and wind speed have a percentage effect of 73.5%, 12.2%, and 14.3%, respectively, on still efficiency. The experiment was conducted over a seven-week period from last week in August to end of second week in October 2022 in Zakho city, Kurdistan, Iraq. This period was characterized by variable weather parameters such as solar radiation, wind speed, atmospheric temperature, atmospheric pressure, dew point, and relative humidity. These variable weather conditions resulted in a wide range of variable daily yields and thermal efficiency values, ranging from 1,200–4,250 mL/d and 26%–45%, respectively. The analysis suggests that the average daily still thermal efficiency is linearly proportional to the incoming total daily solar radiation, with daily deviations from this linear average caused by other variable weather parameters.

2023-06

Environmental Science and Pollution Research (Volume : 30)

A new model has been developed to determine the optimal tilt angle for PV panels and solar collectors on a yearly, seasonal, and monthly basis. The model estimates the diffusion component of solar radiation using Orgill and Holland’s model, which relates the diffusion fraction of solar radiation to the sky clearness index. Empirical data on the clearness index is used to derive the relationship between the diffusion and direct components of solar radiation at any global latitude on any given day of the year. By maximizing the total amount of diffused and direct radiation, the optimal tilt angle for each month, season, and year is determined relative to the latitude angle. The model is programmed in MATLAB and is freely available for download from the MATLAB file exchange website. The model shows that small deviations from the optimal inclination angle have only a minor effect on overall system yield. The monthly optimal tilt angles predicted by the model are consistent with experimental data and other published model predictions for various locations around the globe. Importantly, unlike some other models, the present model does not predict negative optimal inclination angles for small northern hemisphere latitudes or vice versa.

2017-09

Science journal o university of Zakho (Issue : 3) (Volume : 5)

Tobacco smoke is enormously harmful to human health, there’s no safe way to smoke. The primary objective of this study is to analyze the role of tobacco smoke compounds and their ability to damage the cardiovascular system and, in particular, to interfere with blood pressure (Brachial and radial pressure), heart rate and partly on the percentage blood Oxygen saturation. A new device has been manufactured which is unique for measuring the level of smoke, to obtained privies readings, the device had fixed to the first reference level and starting up from it. The effect of smoking has been studied on (26) male passive (26) active smoker volunteer, (14) female passive and (14) female active smoker participants. The results have been showed that the blood pressure and heart rate has been increased with increasing the number of cigarettes in both genders for passive and active smokers. However, this effect for male was more pronounced comparing with females for passive and active smokers. In the case of oxygen saturation concentration percentage, for males the change of oxygen concentration percentage was not stable. In other words, it was fluctuated with the number of cigarettes. But for females the oxygen concentration was decreased but not too much. This means that this effect was not pronounced. this study found that the most pronounced effect has been shown by male’s comparison to females for both passive and active smokers. As well as in nonsmoker’s males, the relation between heart rate and smoke level is inversely proportional. While in male and female smokers and female nonsmokers the relation is proportional. In all cases the relation between the smoke level and time of smoking is inversely proportional. Finally, males& females are affected differently by tobacco use; the sensitivities to smoke for males are higher than in females for passive and active smokers in both brachial and radial blood pressure measurement.

2015-05

Journal of Environment Protection and Sustainable Development (Issue : 2) (Volume : 1)

Nonlinear regression is applied to compiled historical data related to mean monthly temperatures, and precipitations for four main cities in Iraq, Results shows significant occurrence of climate changes. The compiled primary data for the four cities and their corresponding starting years are Baghdad (1887), Mosul (1900), Basra (1923), and Kurkuk (1935). The ending year for all four data sets is 2013. The main two manifestations of such climate change are temperatures increases coupled decrease in precipitations. Extrapolation to future predictions for temperature agrees well with conclusions of the Intergovernmental Panel for Climate Change 2007 (IPCC2007) report on green house effect warming.

2015-02

International Journal of Advanced and Applied Sciences (Issue : 2) (Volume : 2)

Hospitals are places that allow patients to rest and recover, and therefore must be quiet inside and in the surrounding neighbourhood. General Zakho Hospital {Kurdistan region-Iraq} was chosen as a sample. The objectives of this study are to investigate the levels of noise pollution in this hospital. Sound levels were recorded in all wards in the hospital using a Digital Sound Level Meter. The results showed that the measured mean equivalent sound levels (Ls) and standard deviation were (53.77 ± 2.43 dBA, 52.1675 ± 2.27 dBA and 52.0462 ± 1.53 dBA) during the morning, afternoon and the evening measurements respectively. The highest mean Ls (55.6 dBA) and maximum (66.777 dBA) noise level during measurement time was observed in Nurse station room. The lowest mean Ls (50.9055dBA) and minimum Ls readings (43.03 dBA) were observed in the Female ward. These observed noise levels exceeded the recommended World Health Organization (30-40dBA) guidelines for hospitals. This study conclude that there is noise pollution problem in this hospital and the major source of noise inside the wards are talking of visitors or patient’s family members, doors opening or closing and patients moaning or crying, whereas talking of visitors or patient’s family members and children playing, Footsteps, renovation of hospitals, shouting of nursing staff and opening or closing are the five major noise sources outside the wards.

2014-08

Applied Physics Research (Issue : 5) (Volume : 6)

Hot cathode and hollow anode argon DC glow discharge plasma at different pressures of (0.04, 0.05, 0.06, 0.07, 0.09, 0.2, 0.4, and 0.8 mbar) has been investigated. The experiments were carried out under the influence of pressure and filament cathode current on voltage – current characteristics of glow discharge and its breakdown voltage. Plasma parameters have been measured and obtained using single probe method at fixed discharge current (Id=1.88 mA) and hollow anode diameter. A computer MATLAB program is performed for this purpose. It was shown that the discharge voltage – current characteristics curve has a positive resistance and represents an abnormal glow region at pressure (0.04 and 0.06) mbar for different filament current. The breakdown voltage increases as the filament current is increased. In different pressure, electron temperature shows different behavior with increasing filament current. Electron density varies nearly inversely with the filament current, but it is increase due to increase of pressure from (1 to 3 mbar), then tends to decrease for the higher pressure. There are two groups of electrons according to the two peaks of (EEDFs), and the peaks amplitude decrease, with the increases of both filament current and gas pressure.

2014-08

Journal of Asian Scientific Research (Issue : 3) (Volume : 4)

This work describes a relatively simple yet effective method for analyzing harmonic distortions and spectral analysis of electronic signals up to the MHz range. The method involves the use a suitable analog or digital oscilloscopes to present the signal, taking a digital picture of the oscilloscope screen, converting the oscilloscope trace to numerical data and performing fast Fourier transform on the data. All MATLAB based software needed for the procedure is given. The results involve the spectrum analysis plot, the overall distortion, and all frequencies up to the tenth harmonic together with their relative amplitudes with respect to that of the fundamental frequency. The program provides for any user’s selected frequency band analysis to be presented.

2013-06

Journal of University of Zakho (Issue : 2) (Volume : 1)

In this work all necessary mathematical formulation needed to calculate the approximate value of the glow discharge plasma electron density is carried out. The formulation is converted to a matlab computer code that can directly give the density. The inputs to the program are the gas pressure, breakdown potential, discharge voltage and current values, and the anode cross section area.

2011-02

Chinese Physics Letters (Issue : 11) (Volume : 28)

Experimental results on some properties of electric discharge initiated by audio frequency voltages in the range of 50–10000 Hz are presented. These results indicate that there are at least two modes of plasma ionic oscillations. A resonance-type behavior is seen when the driving field frequency becomes equal to the plasma ionic frequency. The results for plasma density and plasma temperature for both modes are presented. (physics of gases, plasmas, and electric discharges)

2008-07

University of Duhok Journal (Issue : 2) (Volume : 11)

A stoichiometric amorphous GeSe and GeSe2 thin films have been prepared by thermal evaporation, The as deposited and after heat treatment films, from room temperature to above the crystallization temperature were examined, by optical and transmission electron microscopes. Laser pulsed beam of various powers have also been used to induce crystallization. Electron diffraction revealed an exact distribution of crystalline spots ov6r halo rings. these observations indicated that the crystallization of both compounds did not accompany by changing atomic bonds brt I rearrangements of atoms lead to crystalline state.