Preferred Language
Articles
/
joe-2194
Performance Analysis of Four Conceptual Designs for the Air Based Photovoltaic / Thermal Collectors
...Show More Authors

The  thermal  and  electrical  performance  of  different  designs  of  air  based  hybrid photovoltaic/thermal collectors is investigated experimentally and theoretically. The circulating air is used to cool PV panels and to collect the absorbed energy to improve their performance. Four different collectors have been designed, manufactured and instrumented namely; double PV panels without cooling (model I), single duct double pass collector (model II), double duct single pass (model III), and single duct single pass (model IV) . Each collector consists of: channel duct, glass cover, axial fan to circulate air and two PV panel in parallel connection. The temperature of the upper and lower surfaces of PV panels, air temperature, air flow rate, air pressure drop, wind speed, solar radiation and ambient temperature were measured. The power produced by solar cells is measured also. A theoretical model has been developed for the collector model IV based on energy balance principle. The prediction of the thermal and hydraulic performance was obtained for the fourth model of PV/T collector by developing a Matlab computer program to solve the numerical model. The experimental results show that the combined efficiency of model III is higher than that of models II and IV. The pressure drop of model III is less than that of models I and IV, by (43.67% and 49%). The average percentage error between the theoretical and experimental results was 9.67%.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Fri Jan 28 2022
Journal Name
Gsc Biological And Pharmaceutical Sciences
Review with checklist of monocot in the herbarium of Iraq Natural History Museum
...Show More Authors

This study was conducted to make an inventory of the monocot plants that were collected before and now which stored in the herbarium of Iraq Natural History Museum for identifying them. The herbarium contains avery large and varied number of plants from different parts in Iraq and for different and varied environments. The plants collected, arranged and identified using taxonomic keys specific to these families. Currently, the plant samples are in the herbarium of Iraq Natural History Museum to be an important scientific reference for all researchers inside and outside the country. With the identification of botanical scientists for each family, gender and year in which it was first diagnosed.

View Publication
Crossref
Publication Date
Tue Jan 31 2023
Journal Name
Iraqi Geological Journal
Reservoir Characterization and Rock Typing of Carbonate Reservoir in the Southeast of Iraq
...Show More Authors

Flow unit and reservoir rock type identification in carbonates are difficult due to the intricacy of pore networks caused by facies changes and diagenetic processes. On the other hand, these classifications of rock type are necessary for understanding a reservoir and predicting its production performance in the face of any activity. The current study focuses on rock type and flow unit classification for the Mishrif reservoir in Iraq's southeast and the study is based on data from five wells that penetrate it. Integration of several methods was used to determine the flow unit based on well log interpretation and petrophysical properties. The flow units were identified using the Quality Index of Rock and the Indicator of Flow Zone. Th

... Show More
Preview PDF
Scopus (8)
Crossref (1)
Scopus Crossref
Publication Date
Mon Sep 23 2019
Journal Name
Baghdad Science Journal
Representation of Algebraic Integers as Sum of Units over the Real Quadratic Fields
...Show More Authors

In this paper we generalize Jacobsons results by proving that any integer  in   is a square-free integer), belong to . All units of  are generated by the fundamental unit  having the forms

our generalization build on using the conditions

This leads us to classify the real quadratic fields  into the sets  Jacobsons results shows that  and Sliwa confirm that  and  are the only real quadratic fields in .

View Publication Preview PDF
Scopus Clarivate Crossref
Publication Date
Wed Feb 25 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Effect of different polishing systems on the surface roughness of full-contour zirconia
...Show More Authors

Background: Adjustment of any premature occlusal contact of any zirconia restoration requires its polishing or glazing in order to restore the smoothness of the restoration. The objective of this in vitro study was to evaluate the effects of different polishing systems and glazing on the surface roughness of full-contour zirconia. Material and methods: Forty disks (diameter: 8 mm, thickness: 6.4 mm) were prepared from pre-sintered full-contoured zirconia block; they were colored and sintered in a high-temperature furnace at 1500ËšC for 8 hours. The specimens were then leveled and finished using grinding and polishing machine and adjusted using diamond disk. The specimens were then randomly divided into four groups (n=10), group I involves

... Show More
View Publication Preview PDF
Publication Date
Tue Mar 14 2023
Journal Name
Res Militaris
The Familiarity of Preparatory Stage Arabic Language Teachers of Higher-Order Thinking Skills
...Show More Authors

The study aimed to find out the degree of practicing Arabic language teachers in the preparatory stage of higher-order thinking skills from their point of view in the first, second and third Baghdad Rusafa directorates of education. The descriptive survey method was used. The study population consisted of teachers of the Arabic language in the directorates of Baghdad, Rusafa, First, Second and Third, and the sample number was (284) teachers. A questionnaire was built on higher-order thinking skills. The validity and reliability of the tool were verified, after which the scale was applied to the research sample of (116) schools and (168) teachers who were randomly selected from the schools affiliated to the Baghdad Education Directorates Rus

... Show More
View Publication Preview PDF
Publication Date
Sun Jun 05 2011
Journal Name
Baghdad Science Journal
Toxicity effects of some heavy metals on the growth of alga Scenedesmus dimorphus
...Show More Authors

The toxicity effect of some heavy metals (Lead, Cadmium, Copper, and Zinc) on the growth of alga Scenedesmus dimorphus which belongs to the Division of Chlorophyta was studied and depended on the total cell number . The growth rate and doubling time were also calculated accordingly in present of absent of the the heavy metals . There were differences in toxic effects of the metals (p<0.05) . The growth was decreased gradually with alga when exposured to Lead at 15,20 and 25 mg/l in comparison with the control , mean while 30 mg/l caused an acute decrease in growth . Treating the alga with 0.05,0.1,0.5 mg/l concentration of Cadmium the number of cells decreased while at 1 mg/l the effect was more pronounced . As for Copper the conc

... Show More
View Publication Preview PDF
Crossref
Publication Date
Wed Jan 20 2021
Journal Name
Plant Archives
The Effect of Plowing and Pulverization Systems on Some Plant Indicators of Onion
...Show More Authors

An experiment was carried out on the fields of the college of Agriculture - Abu Ghraib, of a silty clay loam soil that has moisture of 15-16%, to study the effect of plowing and pulverization systems on some plant indicators of onion. The experiment included plowing systems with three levels (plowing with a moldboard plow, plowing by chisel plow and zero tillage plowing) as a primary factor. The second factor was that pulverization for only one time and repeating the pulverization twice through the use of the rotary tiller. The plant indicators of onion that are studied: plant length, onion diameter, onion weight and onion neck diameter. The experiment has carried out according to SPLIT PLOT design according to RCBD design by three replicat

... Show More
View Publication Preview PDF
Publication Date
Sun Feb 17 2019
Journal Name
Iraqi Journal Of Physics
A Study of the electronic structure of CdS Nanocrystals using density functional theory
...Show More Authors

Density Functional Theory at the generalized-gradient approximation level coupled with large unit cell method is used to simulate the electronic structure of (II-VI) zinc-blende cadmium sulfide nanocrystals that have dimensions 2-2.5 nm. The calculated properties include lattice constant, conduction and valence bands width, energy of the highest occupied orbital, energy of the lowest unoccupied orbital, energy gap, density of states etc. Results show that lattice constant and energy gap converge to definite values. However, highest occupied orbital, lowest unoccupied orbital fluctuates indefinitely depending on the shape of the nanocrystal.

View Publication Preview PDF
Crossref
Publication Date
Sat Dec 01 2012
Journal Name
Iraqi Journal Of Physics
The effect of additive carbon nano tube on optical properties of epoxy resin
...Show More Authors

In this work, MWCNT in the epoxy can be prepared at room temperature and thickness (1mm) at different concentration of CNTs powder. Optical properties of multi-walled carbon nanotubes (CNTs) reinforced epoxy have been measured in the range of (300-800)nm. The electronic transition in pure epoxy and CNT/epoxy indicated direct allowed transition. Also, it is found that the energy gap of epoxy is 4.1eV and this value decreased within range of (4.1-3.5)eV when the concentration of CNT powder increased from (0.001-0.1)% respectively.
The optical constants which include (the refractive index (n), the extinction coefficient (k), real (ε1) and imaginarily (ε2) part of dielectric constant calculated in the of (300-800)nm at different concent

... Show More
View Publication Preview PDF
Publication Date
Fri Dec 01 2023
Journal Name
Nano Biomedicine And Engineering
The Impact of Modified Metallic Nanoparticles on Thermomechanical Properties of PMMA Soft Liner
...Show More Authors

View Publication
Scopus (4)
Crossref (2)
Scopus Crossref