The present work aimed to examine the nature and degree of the cross-correlations among three different ionospheric indices: these are Optimum Working Frequency (OWF), Highest Probable Frequency (HPF), and Best Usable Frequency (BUF). VOCAP and ASASPS models were adopted to determine the datasets of the selected ionospheric indices. The determination was made for different transceiver stations that provide certain HF connection links during the minimum and maximum years of solar cycle 24, 2009 and 2014, respectively. Matlab program was implemented to produce the geodesic parameters for the selected transceiver stations. The determination was made for different path lengths (500, 1000, 1500, and 2000) Km and bearings (0o, 45o, 90o ........ 315o). Different correlation methods were used to examine the best determination coefficient values between the tested parameters. A third-order polynomial equation was set as the best correlation method that gave a better description for the correlation among the tested parameters. The proposed mathematical correlation equations were used to predict the seasonal values of the (HPF, OWF and BUF) parameters. The proposed equations were verified by comparing their values with the observed datasets during the study years. Also, the predicted values were tested using different statistical methods, which gave good results for all tested cases. يهدف العمل الحالي إلى دراسة طبيعة ودرجة الترابط بين ثلاثة مؤشرات آيونوسفيرية مختلفة وهي (HPF,OWF and BUF), تم استخدام نماذج VOCAP و ASASPS لحساب قيم البيانات للمؤشرات الآيونوسفيرية المختارة. اجريت الحسابات لمحطات الإرسال / الاستقبال المختلفة التي توفر روابط اتصال عالية التردد خلال سنوات الصغرى والعظمى للدورة الشمسية 24 (2009 و 2014) على التوالي. تم تنفيذ برنامج Matlab لايجاد قيم المعلمات الجيوديسية لمحطات الإرسال / الاستلام لأطوال مسافات مختلفة (500، 1000، 1500 و 2000) كم واتجاهات مختلفة(0o, 45o, 90o ........ 315o). تم تطبيق طرق ارتباطية مختلفة لاختبار افضلها بين المعاملات المختبرة . تم اقتراح معادلات رياضية متعددة الحدود (الدرجة الثالثة) كأفضل طريقة تصف القيم الارتباطية بين المعاملات المحددة لغرض الدراسة. تمكنت المعادلات المقترحة من التنبؤ بالقيم الموسمية للمؤشرات ((HPF و(OWF) و (BUF).و تم التحقق منها من خلال مقارنتها مع قيم المعلمات المرصودة خلال سنوات الدراسة . كما تم اختبار القيم المتوقعة باستخدام طرق إحصائية مختلفة والتي قدمت نتائج جيدة لجميع الحالات المختبرة
In this paper, thermal performance of a zig-zig solar air heater (ZZSAH) with and without using steel wire mesh on the absorber plate of the collector is experimentally investigated. The experimental work includes four inclination angles of the collector 20o, 30o, 45o, and 60o and four air mass flow rates of 0.03, 0.04, 0.06, and 0.08 kg/s under varieties of operating conditions of a geographic location of Baghdad. New correlation equations of Nusselt number are obtained from experimental results for both types of collectors where the effect of varying of the inclination angle of collector taken into consideration in the experiment. The correlations show good agreement wi
... Show MoreNumerical study has been conducted to investigate the thermal performance enhancement of flat plate solar water collector by integrating the solar collector with metal foam blocks.The flow is assumed to be steady, incompressible and two dimensional in an inclined channel. The channel is provided with eight foam blocks manufactured form copper. The Brinkman-Forchheimer extended Darcy model is utilized to simulate the flow in the porous medium and the Navier-Stokes equation in the fluid region. The energy equation is used with local thermal equilibrium (LTE) assumption to simulate the thermofield inside the porous medium. The current investigation covers a range of solar radiation intensity at 09:00 AM, 12:00 PM, and 04:00
... Show MoreThe present study explores the solar-induced photocatalytic degradation of reactive red (RR) and reactive turquoise (RT) dyes in a single system using TiO2 immobilized in xanthan gum (TiO2/XG), synthesized using the sol–gel dip-coating technique for direct precipitation. SEM-EDX, XRD, FTIR, and UV–Vis were used to assess the characteristics of the resulting catalyst. Moreover, the effects of different operating parameters, specifically pH, dye concentration, TiO2/XG concentration, H2O2 concentration, and contact time, were also investigated in a batch photocatalytic reactor. The immobilized TiO2/XG catalyst showed a slight adsorption degradation efficiency and then improved the RR and RT dye degradation activity (92.5 and 90.8%
... Show MoreCu (In, Ga) Se2 (CIGS) nano ink were synthesized from molecular precursors of CuCl, In Cl3, GaCl3 and Se metal heated to 240 °C for 1 hour in N2-atmosphere to form CIGS nanocrystal ink, Thin films were deposited onto Au/soda-lime glass (SLG) substrates. This work focused on CIGS nanocrystals, including their synthesis and application as the active light absorber layer in photovoltaic devices (PVs). This approach, using spin-coating deposition of the CIGS light absorber layers (75 mg/ml and 150 nm thickness), without high temperature selenization, has enabled up to 1.398 % power conversion efficiency under AM 1.5 solar illumination. X-ray diffraction (XRD) studies show that the structural formation of CIGS chalcopyrite structure. The mo
... Show MoreThis paper introduces a complete design and simulation of a controller for the double fed induction generator (DFIG) turbine. The work also included the solar updraft tower (SUT) design to supply Al-Mahmoudia hospital in Baghdad/Iraq. The design includes the daily average load estimation, annual solar irradiance and, temperature monitoring, and logging.
According to the data obtained from the Ministry of Science and Technology, Baghdad has low wind speed. Therefore, the (SUT) has been designed to generate electrical power depending on the difference between the external and internal air temperature. The temperature difference will generate a suitable airspeed to drive the wind turbine, connected to the proposed (DFIG) generators
... Show MoreThe photocatalyst process is considered the most promising method for the removal of water contamination. For excellent chemical and structural properties of Co3O4 nanoparticles, various Co3O4-based nanostructures can be applied as a photocatalyst. In this work, carbon quantum dots is prepared via an eco-friendly process and linked to Co3O4 effectively. X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible absorption spectroscopy and Fourier transform infrared spectroscopy (FT-IR). The photocatalyst process reveals that prepared nanocomposites can be degraded methylene blue under solar irradiation strongly. Results showed that methylene blue and methyl orange are degraded via
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