In this paper thermo-hydrodynamic characteristics were investigated experimentally for a new type shell-helical coiled tube heat exchanger used as a storage tank of closed loop solar water heater system. Triple concentric helical coils were made of copper tubes of (12.5mm OD and 10mm ID) with coils diameter of (207, 152.2, 97mm) for outer, middle and inner coils respectively. The experiments were carried out during a clear sky days of (March and April 2012). The parameters studied in this work are: history of average temperature of shell side of the storage tank, collector heat gain, heat rejected from coils to shell side of the storage tank, collector efficiency, thermal effectiveness of the heat exchanger (storage tank), and pressure drop. These parameters were studied at four different circulating mass flow rates of (1.8, 3, 6, 9 l/min) and for two consuming modes of supply water namely no withdrawal, and continuous withdrawal of (1 l/min). The results show that stratification temperature in the storage tank is increased for no withdrawal compared with water withdrawal, also the shell side average temperature increases with increased solar time. Collector efficiency is increased with increasing circulation flow rates, also increases with water withdrawn from storage tank. The pressure drop decreases with the increase of solar radiation .
The work in this paper involves the planning, design and implementation of a mobile learning system called Nahrain Mobile Learning System (NMLS). This system provides complete teaching resources, which can be accessed by the students, instructors and administrators through the mobile phones. It presents a viable alternative to Electronic learning. It focuses on the mobility and flexibility of the learning practice, and emphasizes the interaction between the learner and learning content. System users are categorized into three categories: administrators, instructors and students. Different learning activities can be carried out throughout the system, offering necessary communication tools to allow the users to communicate with each other
... Show MoreIn this study, the response and behavior of machine foundations resting on dry and saturated sand was investigated experimentally. In order to investigate the response of soil and footing to steady state dynamic loading, a physical model was manufactured. The manufactured physical model could be used to simulate steady state harmonic load at different operating frequencies. Total of (84) physical models were performed. The parameters that were taken into considerations include loading frequency, size of footing and different soil conditions. The footing parameters were related to the size of the rectangular footing and depth of embedment. Two sizes of rectangular steel model footing were used (100 200 12.5 mm) and (200 400 5.0 mm).
... Show MoreDue to the deterioration of water quality within the last few years because of the increase of water consumption and the waste water production and disposal into the river The water quality in both surface and ground water resources was negatively affected .The concept of water quality index is used as a tool for water quality classification in Tigris River within Baghdad City .Twenty two parameters of pollution were selected to measure the water quality indices of Tigris river within Baghdad city .Those parameters were measured during (2000-2004)as average monthly values ,three water treatment plants were selected out of the eight water treatment plants that exist along the river.Al Kharkh water treatment plant to reflect the water quality
... Show MoreThere is no access to basic sanitation for half the world's population, leading to Socioeconomic issues, such as scarcity of drinking water and the spread of diseases. In this way, it is of vital importance to develop water management technologies relevant to the target population. In addition, in the separation form of water treatment, the compound often used as a coagulant in water treatment is aluminum sulfate, which provides good results for raw water turbidity and color removal. Studies show, however, that its deposition in the human body, even Alzheimer's disease, can cause serious harm to health and disease development. The study aims to improve the coagulation/flocculation stage related to the amount of flakes, i
... Show MoreAn improved Metal Solar Wall (MSW) with integrated thermal energy storage is presented in this research. The proposed MSW makes use of two, combined, enhanced heat transfer methods. One of the methods is characterized by filling the tested ducts with a commercially available copper Wired Inserts (WI), while the other one uses dimpled or sinusoidal shaped duct walls instead of plane walls. Ducts having square or semi-circular cross sectional areas are tested in this work.
A developed numerical model for simulating the transported thermal energy in MSW is solved by finite difference method. The model is described by system of three governing energy equations. An experimental test rig has been built and six new duct configurations have b
Recognition is one of the basic characteristics of human brain, and also for the living creatures. It is possible to recognize images, persons, or patterns according to their characteristics. This recognition could be done using eyes or dedicated proposed methods. There are numerous applications for pattern recognition such as recognition of printed or handwritten letters, for example reading post addresses automatically and reading documents or check reading in bank.
One of the challenges which faces researchers in character recognition field is the recognition of digits, which are written by hand. This paper describes a classification method for on-line handwrit
... Show MoreDealing with this study to find a link principle in the construction of the system and disorder to the promise of the principles and concepts of intellectual and philosophical form and content in the act of interior design of the halls education in the Ministry of Labor and Social Affairs , which leads to a reaction design objective and functionally and to increase the strength of the effect on users of the coaches and trainers . As it informs the side cognitive and developmental study of the design of the interior spaces . So it was the goal of research in the detection of the nature of the system and disorder with Focus indicators and the type of regulations and privacy and what constitutes the framework of knowledge in order to explai
... Show MoreMonitoring water quality in hemodialysis systems is extremely important to maintain adequate quality services for patients suffering from kidney failure. This work aims to examine and evaluate bacteriological characteristics and endotoxin contamination levels in hemodialysis water produced in dialysis centers. Forty‐eight water samples were collected and analyzed from four major hospitals in Baghdad for one year to evaluate seasonal effects. The analysis included the determination of total heterotrophic bacteria using the pour plate method, identification of bacterial isolate using the Vitek2 compact instrument, and the determination of endotoxins levels using Limulus ameboc
This research is focusing on finding more effective polymers that leads to enhance the rheological properties of Water Base Muds. The experiments are done for different types of mud for all substances which are Polyacrylamide, Xanthan gum, CMC (Carboxyl Methyl Cellulose). This study shows the effect of add polymer to red bentonite mud, effect of add polymer to Iraqi bentonite mud, the effect of add bentonite to polymer mud. The mud properties of Iraqi bentonite blank are enhanced after adding the polymers to the blank mix, CMC gives the highest value of plastic viscosity and Gel strength than others; X-anthan gives the highest value of yield point and gel strength than others. For the red bentonite mud, Polyacrylamide ha
... Show MoreThe alteration in the hydrological regime in Iraq and the anthropogenic increasing effect on water quality of a lotic ecosystems needs to continuous monitoring. This work is done to assess the water quality of Tigris River within Baghdad City. Five sites were selected along the river and ten physicochemical parameters and Overall Index of Pollution (OIP) were applied to assess the water quality for the period between November 2020 and May 2021, the studied period were divided into dry and wet seasons. These parameters were water temperature, pH, dissolved oxygen (DO), biological oxygen demand (BOD), total hardness, alkalinity, turbidity, total phosphorus, total nitrogen, electrical co