Preferred Language
Articles
/
shY5jIcBVTCNdQwCdVWk
Power Efficiency Maximization in Cognitive Radio Networks
...Show More Authors

Cognitive radio technology is used to improve spectrum efficiency by having the cognitive radios act as secondary users to access primary frequency bands when they are not currently being used. In general conditions, cognitive secondary users are mobile nodes powered by battery and consuming power is one of the most important problem that facing cognitive networks; therefore, the power consumption is considered as a main constraint. In this paper, we study the performance of cognitive radio networks considering the sensing parameters as well as power constraint. The power constraint is integrated into the objective function named power efficiency which is a combination of the main system parameters of the cognitive network. We prove the existence of optimal combination of parameters such that the power efficiency is maximized. Then we reformulate the objective function to incorporate the throughput. According to different constraints or degree of significance, we may put proper weight to each term so that we could obtain more preferable combination of parameters. Computer simulations have given the optimal solution curve for different weights. We can draw the conclusion that if we put more emphasis on power efficiency, the transmit power is a more critical parameter, however if throughput is more important, the effect of sensing time is significant.

Scopus Crossref
View Publication
Publication Date
Mon Mar 23 2020
Journal Name
Journal Of Engineering
Improving Photovoltaic Panel (PV) Efficiency via Two Axis Sun Tracking System
...Show More Authors

In this paper two axis sun tracking method is used to absorb maximum power from the sun's rays on the solar panel via calculating the sun’s altitude and azimuth angles, which describe the solar position on the Iraqi capital Baghdad for the hours 6:00, 7:00, 8:00, 9:00, 12:00, 15:00 and 17:00 per day. The angles were calculated in an average approach within one month, so certain values were determined for each month. The daily energy achieved was calculated for the solar tracking method compared with the fixed tracking method. Designed, modeled and simulated a control circuit consisting of reference position truth table, PI Controller and two servomotors that tracked the sun position to adjust the PV panel perpendicular

... Show More
View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Sun Jun 12 2011
Journal Name
Baghdad Science Journal
Hybrid(Luminescent and Fresnel ) Concentrators to Improve Solar Panel Conversion Efficiency
...Show More Authors

The spectral response of the Si solar cell does not coincidence with the sun irradiance spectrum, so the efficiency of the Si solar cell is not high. To improve the Si solar cell one try to make use of most region of the sun spectrum by using dyes which absorb un useful wavelengths and radiate at useful region of spectrum (by stock shift). Fluorescence's dye is used as luminescent concentrator to increase the efficiency of the solar cell. The results show that the performance efficiency and out power for crystalline silicon solar cells are improved.

View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Sat Mar 30 2002
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Study of the Factors Affecting the Efficiency of Reverse Osmosis Process
...Show More Authors

View Publication Preview PDF
Publication Date
Sat Jan 19 2019
Journal Name
Iraqi Journal Of Agricultural Sciences
USING PROBABILITY REGRESSION MODELS TO MEASURING MANAGEMENT EFFICIENCY FOR BROILER PROJECTS
...Show More Authors

The efficiency of management is determining factor for the success or failure of agricultural projects generally and Livestock particularly achieving its objectives. Therefore, this research came to diagnose the most important variables that determine the efficiency of management using the probability regression models to measure the probability of management efficient of broilers production projects using  random sample included (60) broilers projects represented 11.6% of Baghdad province (research community) in 2016. After estimating the relationship between the management efficiency (descriptive dependent variable) and the independent variables affecting it (age, educational level, production index (PI), experience). The results

... Show More
View Publication
Crossref (1)
Crossref
Publication Date
Tue Jan 01 2019
Journal Name
Eurasian Chemico --technological Journal
Influence of addition (Mn) on enhance efficiency of (CuInTe2) photovoltaic cell
...Show More Authors

Publication Date
Sun Feb 25 2024
Journal Name
Iraqi Journal Of Agricultural Sciences
THE EFFICIENCY OF GUM-SILICA CMPOSITE FOR REMOVING OF WASTEWATER TURBIDITY
...Show More Authors

A novel mixed natural coagulant has been developed to remove sewage pollutants and heavy metals from Qanat- al- Jayesh by using low cost adsorbent natural materials. In these materials, significant interaction contains Arabic gum mixed with extracted silica from rice husk ash (natural coagulants) by the Batch device approach, using two variables, pH values ranging from 5-8 and contact times between 0.25-5 hrs. All wastewater samples were collected after treatment by adsorbents and examined for determination of residual heavy metal concentrations: Pb, Ni, Zn and Cu by atomic absorption spectroscopy (AAS), turbidity, pH, total dissolved salts (TDS), electrical conductivity (EC) and total salinity (TS). The results obtained indicate Th

... Show More
View Publication
Scopus (5)
Crossref (5)
Scopus Crossref
Publication Date
Sun Mar 01 2026
Journal Name
Journal Of Solid State Chemistry
Novel CoCdFe2O4/Chitosan–PANi ternary nanocomposite for High-Efficiency Lead Removal
...Show More Authors

View Publication Preview PDF
Scopus (2)
Crossref (2)
Scopus Crossref
Publication Date
Sun Feb 25 2024
Journal Name
Iraqi Journal Of Agricultural Sciences
THE EFFICIENCY OF GUM-SILICA CMPOSITE FOR REMOVING OF WASTEWATER TURBIDITY
...Show More Authors

A novel mixed natural coagulant has been developed to remove sewage pollutants and heavy metals from Qanat- al- Jayesh by using low cost adsorbent natural materials. In these materials, significant interaction contains Arabic gum mixed with extracted silica from rice husk ash (natural coagulants) by the Batch device approach, using two variables, pH values ranging from 5-8 and contact times between 0.25-5 hrs. All wastewater samples were collected after treatment by adsorbents and examined for determination of residual heavy metal concentrations: Pb, Ni, Zn and Cu by atomic absorption spectroscopy (AAS), turbidity, pH, total dissolved salts (TDS), electrical conductivity (EC) and total salinity (TS). The results obtained indicate Th

... Show More
View Publication
Scopus (5)
Crossref (5)
Scopus Crossref
Publication Date
Fri Nov 10 2023
Journal Name
Chalcogenide Letters
Enhancement efficiency of cadmium selenium solar cell by doping within silver
...Show More Authors

We studied at the morphology, structural setup, and optical characteristics of thin cadmium (CdSe) films a thickness of 250 nm that were created by thermal evaporation over glass, The films exhibited a hexagonal shape were crystalline, and tended to form grains in the (111) crystallographic direction, according to the X-ray diffraction examinations. These characteristics were established using the investigation's findings. Through the use of thin films of CdSe doped with Ag at a concentration of 1.5%, the crystal structure orientations for pure CdSe (25.32, 41.84) and CdSe:Ag (25.39, 41.01) that were both pure as well as those that were doped with silver were both determined. The band gap of the optical spectrum decreased by 1.93–

... Show More
View Publication
Scopus (10)
Crossref (8)
Scopus Clarivate Crossref
Publication Date
Mon Jan 01 2024
Journal Name
Journal Of Stomatology
The effect of Winter’s red line, angle of impaction, and radio-morphometric indices on surgical difficulty of impacted mandibular third molar: a prospective observational study
...Show More Authors

View Publication
Scopus (1)
Crossref (1)
Scopus Crossref