ARO-THE SCIENTIFIC JOURNAL OF KOYA UNIVERSITY
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Mechanical Properties of Welded Deformed Reinforcing Steel Bars
Get PDFReinforcement strength, ductility and bendability properties are important components in design of reinforced concrete members, as the strength of any member comes mainly from reinforcement. Strain compatibility and plastic behaviors are mainly depending on reinforcement ductility. In construction practice, often welding of the bars is required. Welding of reinforcement is an instant solution in many cases, whereas welding is not a routine connection process. Welding will cause deficiencies in reinforcement bars, metallurgical changes and re-crystallization of microstructure of particles. Weld metal toughness is extremely sensitive to the welding heat input that decreases both of its strength and ductility. For determining the effects of welding in reinforcement properties, 48 specimens were tested with 5 different bar diameters, divided into six groups. Investigated parameters were: properties of un-welded bars; strength, ductility and density of weld metal; strength and ductility reduction due to heat input for bundled bars and transverse bars; welding effect on bars’ bending properties; behavior of different joint types; properties of three weld groove shapes also the locations and types of failures sections. Results show that, strength and elongation of the welded bars decreased by (10-40%) and (30-60%) respectively. Cold bending of welded bars and groove welds shall be prevented
VOLUME 3, NO 1 (2015)
No full textYou are now browsing the fourth issue (Vol III, No 1) of Aro the Scientific Journal of Koya University. Aro is now starting the third year of its journey and it continues to become a globally recognized scientific journal with wider local impact. The editorial team is determined to keep the path of such a mission and sustain Aro’s future publications with quality and reliability in mind.Aro was created with long-term visions of becoming accessible to all researchers in Kurdistan and beyond, and covering a wide range of scholarly disciplines in sciences. The focus of the journal is to reflect that of the Koya University, namely promoting scientific knowledge and research in Kurdistan and secure a brighter future in education. Aro aspires to become a channel for exchange of scholarly research by establishing academic connections between scholars.Aro is a journal of original scientific research, global news, and commentary. The Aro Scientific Journal is a peer-reviewed, open access journal that publishes original research articles as well as review articles in areas of natural sciences and technology. In this issue you will have access to genuine research paper in variety of areas, such as biochemistry, engineering and material.Aro is a member of CrossRef, which is a not-for-profit membership association whose mission is to enable easy identification and use of trustworthy electronic content by promoting the cooperative development and application of a sustainable infrastructure. Aro is also has become member of and indexed by many organizations, e.g., ROAD, Google Scholar, ResearchGate, WorldCat, CiteFactor, etc.Beside its online publications, Aro has a semi-annual hard copy publication which is available free-of-charge.The warm response from researchers, academics and professionals in the last two years has made us to create a wider Editorial Board which serves the wider submitted scientific manuscripts. However, it is clear that having a dedicated and well organized editorial board for the journal is only one side of the coin. The other is the ability to attract submissions of quality research and scholarly work. We are thankful to all of those who put their trust in Aro and presented their original research work for publication in Vol III, No 1 of the journal, as well as, our thanks are extended to the 12 peer-reviewers from the universities worldwide for their efforts in reviewing this issue of Aro publications. Your support and feedback are invited and appreciated. Sincerely Wali M. HamadExecutive PublisherDilan M. Rostam, Shwan K. Rachid, Salah I. Yahya and Sarkawt S. AbdulrahmanExecutive Editorial Boar
Effect of Fatty Acids on Production and Immunological Status of Vaccinated Broiler Chickens
Get PDFThis study was conducted on 400 one day-old male broiler chicks (Ross-308) randomly divided to 2 main groups, 1st main group (GA) feeding basal diet with medium chain fatty acid (MCFA) at rate of 0.15% and divided to four subgroups, 3 subgroups vaccinated with different routes with Newcastle Disease (ND) and non-vaccinated group. The 2nd main group (GB) feeding basal diet without MCFA and divided as the same 1st main gruop. The parameters used in this study included: body weight (BW), phagocytic index (PI), stress index (SI) and weight of spleen and bursa of Fabricious. The aim of this study to evaluate the effect of (MCFA) on these parameters. The experiment lasted for 42 days. Results indicated that additional dietary fatty acid (FA) significantly increased average body weight during the different weeks of the experiment over the basal diet group of birds. Data of PI revealed that birds fed FA supplemented diet had lower values of PI than the basal diet on 2W and the reverse was true on 4W of the experiment. The non-vaccinated birds, on the other hand, showed lowest PI values on 2W and 4W of age. As for, SI a pronounced difference was found due to the two types of diet, and the vaccination methods, as well
Optical Properties of the Synthesized Cr2S3 Nanoparticles Embedded in Polyvinyl Alcohol
Get PDFPolyvinyl alcohol (PVA) based nanocomposite, with different concentrations of chromium sulfide Cr2S3 nanoparticles, were prepared by reduction of Cr(NO3)3 and Na2S in an aqueous PVA solution, using the chemical reduction rote, and casting technique. Effect of Cr2S3 nanoparticles on optical parameters such as absorbance, absorption coefficient, refractive index, and extinction coefficient have been investigated using UV-Visible spectroscopy. The study reveals that all these parameters are affected by the Cr2S3 nanoparticles concentration. The study has been also extended to investigate the changes in the optical band gap energies, the band tail width for the samples using Tauc and Urbach relations respectively. The optical energy band gap reduced from (6.17 eV) for pure PVA to (4.14 eV) for 0.04M Cr2S3; while the Urbach tail increased from (0.216 eV) for pure PVA to (0.523 eV) for 0.04M Cr2S3. The significant change of the optical properties of PVA with embedded Cr2S3 nanoparticles suggested their applicabilit in optical devices
The Suitability of Limestone from Pilaspi Formation (Middle-Late Eocene) for Building Stone in Koya Area, NE Iraq
Get PDFSuitability of limestone rocks has a crucial importance when stones are used for constructing modern structure. The purpose of this study is to clarify the links between physical, mechanical properties of limestone rocks, also their quality to use as building materials. A total of six limestone rock samples were collected from three different outcrops locations within Pilaspi Formation in Koya area. Engineering geological and geotechnical properties of the limestone rocks in the study area were determined based on the field studies and laboratory tests. The field studies included observations/ measurements of rock mass characteristics such as color, grain size, orientation, bedding thickness and weathering state of the rock materials also spacing, persistence, roughness and infilling material of the discontinuities. Laboratory tests were carried out for determining water content, water absorption, density, uniaxial compressive strength, slake durability and porosity of the rock materials. The study results go well with the national and international standards (Iraqi Standards, 1989; American Society for Testing and Materials, 2004; International Society for Rock Mechanics, 1981) and have shown that the limestone rocks are acceptable for building stone
Objective Gender and Age Recognition from Speech Sentences
Get PDFIn this work, an automatic gender and age recognizer from speech is investigated. The relevant features to gender recognition are selected from the first four formant frequencies and twelve MFCCs and feed the SVM classifier. While the relevant features to age has been used with k-NN classifier for the age recognizer model, using MATLAB as a simulation tool. A special selection of robust features is used in this work to improve the results of the gender and age classifiers based on the frequency range that the feature represents. The gender and age classification algorithms are evaluated using 114 (clean and noisy) speech samples uttered in Kurdish language. The model of two classes (adult males and adult females) gender recognition, reached 96% recognition accuracy. While for three categories classification (adult males, adult females, and children), the model achieved 94% recognition accuracy. For the age recognition model, seven groups according to their ages are categorized. The model performance after selecting the relevant features to age achieved 75.3%. For further improvement a de-noising technique is used with the noisy speech signals, followed by selecting the proper features that are affected by the de-noising process and result in 81.44% recognition accuracy
Optimizing the Flexural Strength of Beams Reinforced with Fiber Reinforced Polymer Bars Using Back-Propagation Neural Networks
Get PDFThe reinforced concrete with fiber reinforced polymer (FRP) bars (carbon, aramid, basalt and glass) is used in places where a high ratio of strength to weight is required and corrosion is not acceptable. Behavior of structural members using (FRP) bars is hard to be modeled using traditional methods because of the high non-linearity relationship among factors influencing the strength of structural members. Back-propagation neural network is a very effective method for modeling such complicated relationships. In this paper, back-propagation neural network is used for modeling the flexural behavior of beams reinforced with (FRP) bars. 101 samples of beams reinforced with fiber bars were collected from literatures. Five important factors are taken in consideration for predicting the strength of beams. Two models of Multilayer Perceptron (MLP) are created, first with single-hidden layer and the second with two-hidden layers. The two-hidden layer model showed better accuracy ratio than the single-hidden layer model. Parametric study has been done for two-hidden layer model only. Equations are derived to be used instead of the model and the importance of input factors is determined. Results showed that the neural network is successful in modeling the behavior of concrete beams reinforced with different types of (FRP) bars
Comparative Study of Terrazzo Tiles Produced in Koya and Erbil , and its Suitability for ts Suitability for Construction Purposes
No full textTiles are durable and have a long lifespan. They may be used as a floor finish for both interior and exterior applications. Experimental and field studies were conducted to investigate the parameters and properties of terrazzo tiles from different regions, namely Erbil and Koya being represented by factories (A) and (B) respectively. These parameters and properties are dimensions, water absorption, modulus of rupture and impact resistance. Test results indicate that the dimensions and modulus of rupture for the tiles from both factories (A) and (B) are conformable with Iraqi specifications, but water absorption of terrazzo tiles from factory (B) does not conform with the Iraqi specification and having surface and total absorption values which are 55.1% and 23.8% higher than that for factory (A) tiles, respectively. The results show that terrazzo tiles of factory (A) have an impact resistance value which is 50% higher than that of tiles from factory (B). The field study which includes questionnaire procedure indicates that 63% of the residents agreed that the terrazzo tiles are beautiful as a floor finishing material and at the same time 94% agreed that this material is expensive. This study shows also that only 20% of Koya residents are satisfied with the quality of the production of factory (B), whereas, 90% of Erbil residents are satisfied with the production of factory (A)
Comparative Study of Different Methods to Determine the Role of Reactive Oxygen Species Induced by Zinc Oxide Nanoparticles
Get PDFAccumulation of reactive oxygen species (ROS) followed by an increase in oxidative stress is associated with cellular responses to nanoparticle induced cell damages. Finding the best method for assessing intracellular ROS production is the key step in the detection of oxidative stress induced injury. This study evaluates and compares four different methods for the measurement of intracellular ROS generation using fluorogenic probe, 2´,7´-dichlorofluorescein diacetate (DCFH-DA). Hydrogen peroxide (H2O2) was utilised as a positive control to assess the reactivity of the probe. Spherically shaped zinc oxide (ZnO) nanoparticles with an average particle size of 85.7 nm were used to determine the diverse roles of ROS in nanotoxicity in Hs888Lu and U937 cell lines. The results showed that different methods exhibit different patterns of ROS measurement. In conclusion this study found that the time point at which the DCFH-DA is added to the reaction, the incubation time and the oxidative species that is responsible for the oxidation of DCFH, have impact on the intracellular ROS measurement
Calculated-Experimental Model for Multilayer Shield
Get PDFThe effective linear attenuation coefficients and build-up factors for single shield of Al, Fe, Pb, and for multi-layer shield of Al-Pb, Al-Fe, Fe-Pb, Al-Fe-Pb as a function of shield thickness, atomic number, and order of the materials composing the shield are investigated for two photon energies of 0.662 MeV and 1.25 MeV. Two derived practical formulas to calculate the effective attenuation coefficient and build-up factor for multilayer shields are used. It is noticed that changing the order of the materials among the shield has no significant effect on the experimental result. Measurement agrees well with the trend of the suggested formulas for calculating the effective attenuation coefficient and the buildup factor. The linear attenuation coefficient is observed to have a strange dependency with the atomic number and photon energy. For single layer shield, the attenuation coefficient increases with decreasing atomic number at low photon energy and increasing with increasing atomic number at high photon energy