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Experimental Study on Double-Pass Solar Air Heater with and without using Phase Change Material
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In this paper, an experimental study was conducted to enhance the thermal performance of a double-pass solar air heater (SAH) using phase change material (PCM) for thermal storage at climatic conditions of Baghdad city - Iraq. The double-pass solar air heater integrated with thermal storage system was manufactured and tested to ensure that the air heating reserved after the absence of the sun. The rectangular cavity filled with paraffin wax was used as a latent heat storage and incorporated into the lower channel of solar air heater. Experiments were carried out to evaluate the charging and discharging characteristics of two similar designed solar air collectors with and without using phase change material at a constant air mass flow rate of (0.0375 kg/sec). The parameters that affect the thermal performance of the SAH with and without the PCMs presented by solar radiation, the difference in air temperature, outlet air temperature, instantaneous thermal efficiency, and daily efficiency are evaluated. The experimental results show that when using the PCM, the temperature of the outlet air was enhanced and increased over the ambient temperature by (1.5 - 6.5 C) after sunset for 5 hours period. It was found that the instantaneous thermal efficiency of the heater using thermal storage exceeds 100% after sunset, this is due to a large amount of heat stored in the paraffin wax that has been released during the discharge process. Also, it was found that the daily efficiency of the double pass SAH integrated with and without thermal energy storage unit was (56, 47%) respectively.

 

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Publication Date
Fri May 01 2015
Journal Name
Journal Of Engineering
On Gradient Descent Localization in 3-D Wireless Sensor Networks
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Localization is an essential demand in wireless sensor networks (WSNs). It relies on several types of measurements. This paper focuses on positioning in 3-D space using time-of-arrival- (TOA-) based distance measurements between the target node and a number of anchor nodes. Central localization is assumed and either RF, acoustic or UWB signals are used for distance measurements. This problem is treated by using iterative gradient descent (GD), and an iterative GD-based algorithm for localization of moving sensors in a WSN has been proposed. To localize a node in 3-D space, at least four anchors are needed. In this work, however, five anchors are used to get better accuracy. In GD localization of a moving sensor, the algo

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Publication Date
Wed Feb 29 2012
Journal Name
Al-khwarizmi Engineering Journal
Effect of Construction Joints on Performance of Reinforced Concrete Beams
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Construction joints are stopping places in the process of placing concrete, and they are required because in many structures it is impractical to place concrete in one continuous operation. The amount of concrete that can be placed at one time is governed by the batching and mixing capacity and by the strength of the formwork. A good construction joint should provide adequate flexural and shear continuity through the interface.

In this study, the effect of location of construction joints on the performance of reinforced concrete structural elements is experimentally investigated.

Nineteen beam specimens with dimensions of 200×200×950 mm were tested. The variables investigated are the location of the construction joints

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Publication Date
Sun Aug 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
The impact of public debt on financial stability in Iraq
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Countries have faced the challenges of high levels of public debt and seek to define the optimum limits to reduce risks to which the financial system can be exposed and its impact on the economy as a whole. Hence the importance of research in studying the impact of internal and external public debt components on indicators of stability of the financial system for the period 2005-2017 for the purpose of knowing the extent of the financial stability indicators response to the high level of the public debt from its optimum ratio, as the aim of the research is to estimate and analyze the dynamic relationship of short and long term between the components of public debt and indicators of financial stability using the (ARDL) model that

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Publication Date
Fri Apr 01 2016
Journal Name
Journal Of Engineering
Satellite Images Classification in Rural Areas Based on Fractal Dimension
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Fractal geometry is receiving increase attention as a quantitative and qualitative model for natural phenomena description, which can establish an active classification technique when applied on satellite images. In this paper, a satellite image is used which was taken by Quick Bird that contains different visible classes. After pre-processing, this image passes through two stages: segmentation and classification. The segmentation carried out by hybrid two methods used to produce effective results; the two methods are Quadtree method that operated inside Horizontal-Vertical method. The hybrid method is segmented the image into two rectangular blocks, either horizontally or vertically depending on spectral uniformity crit

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Publication Date
Sun Mar 03 2013
Journal Name
Baghdad Science Journal
Effect of Magnetic Water Treatment on Prevention of CaCO3 Scales
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Permanent magnets of different intensities were used to investigate the effect of a magnetic field in the process of preventing deposits of calcium carbonate. The magnets were fixed on the water line from the tap outside. Then heating a sample of this water in flasks and measuring the amount of sediment in a manner weighted differences. These experiments comprise to the change of the velocity of water flow, which amounted to (0.5, 0.75, 1) m/sec through the magnetic fields that are of magnetic strength (2200, 6000, 9250, 11000) Gauss, and conduct measurements, tests and compare them with those obtained from the use of ordinary water.The results showed the effectiveness of magnetic treatment in reducing the rate of deposition of calcium carb

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Publication Date
Wed Dec 30 2015
Journal Name
College Of Islamic Sciences
The impact of Arab civilization   On the first century AH
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The influx of Arab Qahtani and Nizari tribes continued to the countries of Baluchistan and the Levant in pre-Islamic times until the Levant became open to the Arab-Islamic tide during the first century AH. The Islamic Orient until the early Islamic Arab Army reached the western borders of China. What we will see in the folds of the search.

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Publication Date
Wed Dec 30 2015
Journal Name
Mathematical Theory And Modeling
On the stability of an SIS epidemic model involving treatment
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The objective of this paper is to study the stability of SIS epidemic model involving treatment. Two types of such eco-epidemiological models are introduced and analyzed. Boundedness of the system is established. The local and global dynamical behaviors are performed. The conditions of persistence of the models are derived.

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Publication Date
Thu Feb 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
The role Government Securities Market on the Iraqi Credit worthiness
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تشكل  التغيرات الحاصلة في اسعار النفط تحديا" حقيقيا" لاستمرار عملية النمو في العراق, وامام الحكومة فرصة كبيرة لإيجاد حلول ناجعة لمشكلة تزايد عجز الموازنة العامة من خلال اللجوء الى اصدار ادوات الدين العام الداخلي والخارجي, وهذا يتطلب بناء استراتيجية لإقامة وتطوير سوق السندات الحكومية في العراق, لتتمكن الحكومة من خلاله توفير مصادر تمويل اضافية, تسهم في تمويل الانفاق الاستثماري الحكومي ودعم النمو ودعم

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Publication Date
Thu Dec 01 2022
Journal Name
International Journal Of Electrical And Computer Engineering (ijece)
A survey on bio-signal analysis for human-robot interaction
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<span lang="EN-US">The use of bio-signals analysis in human-robot interaction is rapidly increasing. There is an urgent demand for it in various applications, including health care, rehabilitation, research, technology, and manufacturing. Despite several state-of-the-art bio-signals analyses in human-robot interaction (HRI) research, it is unclear which one is the best. In this paper, the following topics will be discussed: robotic systems should be given priority in the rehabilitation and aid of amputees and disabled people; second, domains of feature extraction approaches now in use, which are divided into three main sections (time, frequency, and time-frequency). The various domains will be discussed, then a discussion of e

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Publication Date
Sun Jul 09 2023
Journal Name
Journal Of Engineering
Effect of Operating Conditions on Reverse Osmosis (RO) Membrane Performance
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The aim of this research is to study the effect of high concentrations of salts, pressure and temperature on the performance of the RO membrane with time. Four different (Na2CO3) concentrations (5000, 15000, 25000 and 35000) ppm and various pressures such as (1, 3 and 5) bars at different temperatures of the feed solution (i.e., 25, 35 and 45) ◦C were used in this work. It was found that, as the concentration of salt and feed temperatures increase, the rejection of the salt decrease. While the salt rejection of the membranes increases with increase of transmembrane pressure.

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