310 research outputs found
The Effects of Blades Number, Blade Thickness, Blade Tip Angle, and Twist Angle on the Performance of the Rotor Wind Turbines
تعتبر محركات الرياح واحدة من المصادر المهمة في توليد الطاقة الكهربائية. ذلك لان تعتبر من مصادر الطاقة المتجددة. كما انها في مقدمة المصادر الصديقة للبيئة.هذا البحث يتناول كيفية زيادة كفاءة هذه المحركات من خلال تسليط الضوء على العوامل الموثرة الرئيسية في في سلوك هذه المحركات. كما يتضمن البحث تقييم عن مدى اعتمادية معامل القدرة لهذه المحركات على معدل سرعة الرياح الخاص بامكان تنصيب هذه المحركات. يستخدم هذا البحث ايضا احد برامج المحاكات لدراسة سلوك المحركات مع تغيير عدد الريش وكذلك زوايها. The paper gives an experimental study on the performance on the wind turbine rotors with several numbers of blades as well as twist angle. The main goal of this study is to demonstrate the effect blades number, tip angles as well as the twist angle of the blades on the power coefficient (Cp) of the rotor. Moreover, this result represents a simple evaluation about the range of depending power coefficient on the average wind speed.
Also, this paper studies the performance of wind turbines which are tested by carrying out 2-dimensional dynamic using ANSYS-Fluent
Creep and shrinkage of ecological self consolidating concrete
Optimizing concrete mixtures with regard to replace a part of cement content with supplementary cementitious materials can prompt the design of ecological-self consolidating concrete. By replacing more than 60% of cement with residual product from other industries such as Fly Ash, Micro Silica, and lime, the energy consumption and CO2 emission of concrete are reduced. This study was performed to monitor the creep and shrinkage of high volume supplementary cementitious material of self consolidating concrete (HVSCM-SCC) and ensure desired performance of concrete. Total sixteen and Twenty Four specimens from different concrete mixtures with different replacement level (up to 75% of cement replacement) were monitored for creep and shrinkage respectively. Moist and accelerated curing regimes were utilized in this study to see the effect of accelerated curing on creep and shrinkage of HVSCM-SCC. Mechanical properties of different age 1,3,7,28,56 and 90 days were conducted. Experiments have shown that 75% level replacement of cement experienced low creep and shrinkage rate than other mixtures. The creep and shrinkage values of HVSCM-SCC were compared to prediction models proposal by AASHTO LRFD (2007), ACI-209R (2009), and AS 3600 (2009) to ensure the validity of these models for HVSCM-SCC
Time-Dependent Prestress Loss Behavior of Girders in Missouri Bridge A7957 Compared with a U.S. Data Set of High-Performance Concrete Bridge Girders
In this study, six precast, prestressed concrete girders were constructed and instrumented to measure prestress losses of bridge A7957 in Missouri. The concrete mixture for the bridge was designed with varying mechanical and rheological properties. High-strength concrete, high-strength self-consolidating concrete, and normal-strength self-consolidating concrete were used to construct the bridge girders. Vibrating wire strain gauges with integrated thermistors were embedded through the girders\u27 cross sections to measure strains and temperatures. The measured short- and long-term prestress losses were compared with those obtained using different empirical models, specified in the AASHTO LRFD Bridge Design Specifications and in the PCI Design Handbook: Precast and Prestressed Concrete. This study also presents a comparison of measured prestress losses with data reported in the literature for different concrete types
Knowledge Management in Islamic Higher Education (a Case Study on Implementation of Knowledge Management Tools in UIN Sgd Bandung)
The demand on the implementation of knowledge management is even greater at higher education institutions as an institution that intersect with many academic activities and the development of a scientific assessment as occurs in UIN Sunan Gunung Jati Bandung. This study tried to explore and analyze how UIN SGD Bandung run management practices and various activities in it, especially within the framework of the management of intellectual assets owned as an important step of applying the knowledge management. More specifically, this study used a qualitative approach with descriptive-holistic methods and case study analysis, have tried to analyze the use of knowledge management tools in UIN SGD Bandung. This study in its analysis found that there are many deficiencies essentially and conceptually in the implementation of knowledge management conducted by the management UIN SGD Bandung. Some knowledge management tools, such as technology infrastructure, collaboration tools, taxonomy, also has not been applied properly. However, the cycle of activities related to the conversion process of knowledge, such as socialization, externalization, combination, and internalization, has been done in UIN SGD Bandung
Efficient and Simplified Modeling for Kerosene Processing Quality Detection Using Partial Least Squares-Discriminant Analysis Regression
Kerosene from various refineries and crudes is used for heating and other purposes in many countries like Iraq;
therefore, it is important to identify its source to recognize and tax any adulteration. In this study, a fast classification technique for kerosene marketed in Iraq was developed with the goal of identifying its quality. The samples were categorized using a supervised partial least squares discriminant analysis (PLS-DA) approach. Multivariate analyses using agglomerative hierarchal clustering and principal component analysis were utilized to identify outliers and sample dissimilarities. The dataset was divided into calibration and prediction sets. The prediction set was used to evaluate the model’s separation performance. The Q2 cross-validation was applied. The PLS-DA models achieved significant accuracy, sensitivity, and specificity, showing strong segregation ability, notably for the calibration set (100% accuracy and 1.00 sensitivity). It was found that kerosene processing can be classified rapidly and non-destructively without the need for complicated analyses, demonstrating the best results for classification even when compared with the classification outcomes of other fuels. This PLS-DA approach has never been looked at before for process quality detection, and the results are comparable to direct kerosene classification with soft independent modeling of class analogy and support vector machines
Pollution Problems in Koya City due to Private Electrical Generators
Koya city, like any other city in the world, faces a critical environmental problem which is global warming and the increase in the rate of production of gaseous pollutants. This research is involved with the negative effects of private Electrical Power Generators (EPGs) on the environment in Koya City. The environmental pollutants resulted from EPGs were investigated by performing an actual study on land for the number of (EPGs), types, and distribution. Koya city is divided into 18 quarters. The investigation covers a period from 2009 to 2017, included. The production of power was increased due to the increase in the number of generators and supplying hours. The power production in 2009 was 23,850 megawatt (MW) whereas it was 49,635 MW in 2017. The amount of fuel consumed in 2009–2017 was relatively increased from 30,000 to 62,500 barrel/year. The total amount of pollutants was increased by about 108% during the period 2009–2017. The results showed that the most significant increase in pollutants was carbon dioxide (CO2). The annual amount of (CO2) emitted in 2009 was 6588 tons whereas it has increased in 2017–13710 tons. The conclusion of this study was that the highest pollution occurred in the center of Koya City in Nabeel quarter, which represented 22% of the whole pollutants
Detection of (FecB) Gene Polymorphism in Local Sheep Breed at Different Area of Iraq
The rate of ovulation has largely influenced by both genetic and environmental factors. Currently, "the Booroola FecB gene" considered as a guide to improve the twin productivity in sheep flocks meanwhile retain the important other features desired in the flock.
This study intended to detect the mutation in FecB gene using PCR-RFLP screening method by using specific primers designed to introduce a point mutation in PCR product of FecB gene. A thirty, local sheep breed from the middle and south part of Iraq were used in this study. FecB gene was detected by forced digestion of PCR products using Eco471 (AvaII) digestion enzyme.
The results of this study revealed the lack of (190bp band wild type) gene mutation in all samples of the study that is meant local Iraqi sheep breed are non-carrier for polymorphism genetic factor. However, future study is highly recommended with a large number of "local sheep" for better understanding of this feature
The Optimal Irradiation of Iraqi Dates Fruit by Gamma Radiation for Disinfestation Purposes
Fig moth E. cautella, considered the most serious pests infest dates and cause economic losses in the field and warehouses in Iraq which produces between 600-700 thousand tons of dates annually. In order to reduce this damage different pest control methods are used and fragmentation of radiation considered one of the newest and innovative way to control this Moth that attack stored dates. Dates, Zahdi variety artificially infested by eggs of Ephestia cautella .Eggs and larvae of insect were irradiated by gamma radiation with different doses between (106 - 397.5Gy) and then irradiated dates stored at 19Co, 30 and 40 days for Larvae and Eggs respectively. Fragmentation of irradiation dose of gamma were used, five periods of irradiation with three different times separating each period (5, 10, 15min). Physical and chemical properties of dates were analyzed. Results showed that the fragmentation technique is comparable with continuous irradiation and effective for eliminating the insect and keeping the dates preserved with high quality. A dose of (165Gy) and (198Gy) required for 100% hatching inability of irradiated eggs. For larvae a dose of (397.5Gy) was enough to achieve mortality of (100%), (87.50%) and (83.33) for (5, 10, 15min) separating time between each irradiation period respectively. Physical and chemical characteristics did not changed as a result of irradiation. Keywords: Ephestia cautella, stored dates, Iraq, fragmentation of irradiation
Data Acquisition and Processing of Hartha Formation in the east Baghdad oil field, Central of Iraq
A three-dimensional survey was carried out to Eastern Baghdad oil field, which consist three parts, the area of (EB South- 2 ) approximately 179,875 km2 and ( EB South-1) is about (602.03) km2, while the space segment (EB South-3) is approximately to (419.095) km2. In this research, was focused on Hartha Formation only. Based on many tests to designation of pre-planning of the survey to get good signal to noise ratio for receivers in addition to the best suit for vibrators distribution and also getting the best signal source where spread of a 60-line impact and the distance between the point of receive and the other are (2 meters), also using (5) vibrators Type (NOMAD 65) with a maximum capacity of (62000 LB) for each shock. Where all processes work such as enhancing signal at the expense of noise, correction CDP gather for Normal Move Out (NMO) and stack them, correction for influence of near-surface time delays (static correction), filtering processes, providing velocity information, increasing resolution and collapsing diffractions and placing dipping events in their correct subsurface locations (migration) This processes are achieved using computers, they include many mathematical processes depend on physical fundamentals. The main processes in seismic data processing include : stacking, deconvolution, and migration. By using the information of EB-1 Well, and making the relationship time-depth curve of EB-1 then following up on getting synthetic to be linked later with seismic data and sections to obtain a real subsurface image
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