CR-39 is a solid state nuclear track detector (SSNTD) that has been used in many research areas. In spite of the assumption that the CR-39 detectors are insensitive to beta and gamma rays, irradiation with these rays can have significant effects on the detector properties. In this study, beta and gamma rays mass attenuation coefficients μ/ρ (cm2 g-1) for the CR-39 detector have been measured using NaI(Tl) scintillation spectrometer along with a standard geometrical arrangement in the energy region of (0.546-2.274) MeV beta rays and standard gamma sources having energy 0.356, 0.5697, 0.6617 and 1.063 MeV. The total atomic cross-section (σtot), total electronic cross-section (σT E) and the effective atomic number (Zeff) of gamma rays at energy of 1keV- 105 MeV have been also calculated using the Winxcom and MathCAD programs. The data base and the calculated results were compared with the measured experimental values. It has been found that the mass attenuation coefficients vary with the type of interaction of radiation, photoelectric interaction gives dominant contribution to the total mass attenuation coefficients for CR-39 detectors. Further, the Zeff changes with change of energy.
Background: Coated archwires have been introduced to improve esthetics during orthodontic treatment. Theaim of the present study was to evaluate and compare the load–deflection characteristics and force levels of six brands of coated nickel titanium orthodontic archwires using palatal and gingival deflection. Materials and methods: Ten round wires (0.016 inch) and ten rectangular wires (0.019x0.025 inch) were obtained from each of six brands (G&H, Opal, Ortho Technology, Dany, Hubit and Astar Companies). The load-deflection properties of these archwires were evaluated by the modified bending test usinga readymade dental arch model in both palatal and gingival directions at 37°C temperature using a universal material testing machi
... Show MoreThe research is dedicated to study technical and dramatic recruitment of the clown character in Child's Theater Shows This research consist of four chapters ; first chapter is dealing with the problem of the research which defined by the following question :" Does the educational and dramatic recruitment of the clown character achieved in Child's Theater Shows?"The research is summarized in sets of points such as :•Make use of this research for the benefit of employees in the child's theater , especially directors, actors, technicians, workers and dress designers .•To benefit concerned educational institutions in the field of child's theater ; such as : child's culture house , theater & cinema office which are belonging to the ed
... Show MoreThis study focuses on studying an oscillation of a second-order delay differential equation. Start work, the equation is introduced here with adequate provisions. All the previous is braced by theorems and examplesthat interpret the applicability and the firmness of the acquired provisions
Metadiscourse markers are means for organizing a writer’s information and create a connection with her/his readers. When students write, they usually focus on one type of these markers that is the interactive markers and belittling the use of the other type which is the interactional markers. That is to say, they emphasize on presenting and organizing their information only. Therefore, this study is conducted to bridge this gap. The researchers have selected 18 thesis abstracts. Nine of them are written by Iraqi students of English and the rest by American students. The aims of the study are to examine the types and sub-types of metadiscourse markers used by American and Iraqi students; investigate comparatively the impact of the metad
... Show MoreCerium oxide CeO2, or ceria, has gained increasing interest owing to its excellent catalytic applications. Under the framework of density functional theory (DFT), this contribution demonstrates the effect that introducing the element nickel (Ni) into the ceria lattice has on its electronic, structural, and optical characteristics. Electronic density of states (DOSs) analysis shows that Ni integration leads to a shrinkage of Ce 4f states and improvement of Ni 3d states in the bottom of the conduction band. Furthermore, the calculated optical absorption spectra of an Ni-doped CeO2 system shifts towards longer visible light and infrared regions. Results indicate that Ni-doping a CeO2 system would result in a decrease of the band gap. Finally,
... Show MoreField experiment was conducted by using two fertilization systems (i.e.) biofertilizers (inoculation with Pseudomonas putida and with Azotobacter chroococcum and non - inoculation) and chemical fertilization (100%, 50% and 25% of recommended by Ministry of Agriculture) to study the influence of these system and interaction on water and grain yield productivity, some growth phytohorones and number of bacterial cells in soil rizosphere of root of wheat crop under water scarcity. The result showed that the integrate fertilization (inoculation with Pseudomonas putida and Azotobacter chroococcum bacterial + 50% of the recommended chemical fertilizer) recorded 5.70 and 5.55 t ha-1, respectively with reducing the chemical fertilizer app
... Show MoreBackground: Excision repair cross-complementing group 2 gene (ERCC2) polymorphisms have been linked as being a risk factor for colorectal cancer (CRC) emergence. However, data from several studies are contradictory. To validate genetic biomarkers of the CRC; the impact of the following ERCC2 polymorphism (rs1799793 and rs238406) was examined on CRC susceptibility among sample of Iraqi population. Methods: A total of 126 subjects were enrolled in this case control study; 78 CRC patients and 48 apparently healthy individuals who are age, gender, smoking status and BMI matched. Polymerase chain reaction (PCR) was used for genotyping, followed by sequencing then the association between genetic polymorphisms and CRC risk was investigate
... Show MoreTwenty purified isolates were obtained by using different soil sources, only twelve isolates belonging to Aspergillus genera depending on cultural and morphological characterization. The isolates were used as alkaline protease producer. The highest proteolytic, enzymatic activity (95.83U/ml) was obtained from
Change detection is a technology ascertaining the changes of
specific features within a certain time Interval. The use of remotely
sensed image to detect changes in land use and land cover is widely
preferred over other conventional survey techniques because this
method is very efficient for assessing the change or degrading trends
of a region. In this research two remotely sensed image of Baghdad
city gathered by landsat -7and landsat -8 ETM+ for two time period
2000 and 2014 have been used to detect the most important changes.
Registration and rectification the two original images are the first
preprocessing steps was applied in this paper. Change detection using
NDVI subtractive has been computed, subtrac