Al-Rafidain Engineering Journal (AREJ)

Abstract
In this work, Natural convection heat transfer from a horizontal cylinder placed in a vented enclosure was investigated numerically to infer the effect of Rayleigh number (Ra) having the values 1*104 , 5*104 and 1*105, the effect of the ratio of the enclosure width to the cylinder diameter (W/D) having the values 1.5, 1.75, 2, 2.25, 2.5, 2.75, 3 and 3.5, the effect of the ratio of the vent size to the enclosure width (O/W) for a range starting from 0 for a closed enclosure to 1 for an enclosure having two vertical walls only, and the effect of time variation, on the Nusselt number (Nu), the mass flow-rate, the flow and temperature patterns as well as the boundary layers, where the results showed that, Nu. number always increased with Ra. Number. Furthermore, Nu. number increased with the increase of the ratio W/D for ratios of O/W greater than 0.25, and Nu. number decreases with the increase of W/D for the range below this value.

Keywords : Convection , Enclosures , Cylinders Heat

A new method for establishing the Forming Limit curve (FLC) in sheet metal forming is introduced in this work. The method is based on varying the strain path by changing the coefficient of friction between the punch and the blank.
Three finite element simulations are used for the hemispherical punch stretching test. One simulation is for the positive minor strain side and two are for the negative minor strain side of the FLC. Relations between the major and the minor strains are deduced from the results of these simulations. These relations are used to draw the FLC.
The curves obtained were compared with experimental results and found to have a good agreement with them.

KEYWORDS strain path, forming limit curve


ABSTRACT
A new method for establishing the Forming Limit curve (FLC) in sheet metal forming is introduced in this work. The method is based on varying the strain path by changing the coefficient of friction between the punch and the blank.
Three finite element simulations are used for the hemispherical punch stretching test. One simulation is for the positive minor strain side and two are for the negative minor strain side of the FLC. Relations between the major and the minor strains are deduced from the results of these simulations. These relations are used to draw the FLC.
The curves obtained were compared with experimental results and found to have a good agreement with them.

KEYWORDS strain path, forming limit curve

Abstract
Cement industry consumes a big amount of water, which is used in both of the industrial processing and in the cooling system. In this paper, an industrial surveying was carried out to evaluate the condition of industrial wastewater produced in Hammam Al-Alil cement factory and to investigate the ability to reuse the cooling water, which was used one time in this factory, in other locations. The results of the study showed that industrial wastewater contain a high concentration of oil and grease (reached to 1800 mg/L) which caused a great concentration of COD (up to 10000 mg/L) in raw samples. The separation of the oil and grease was very effective in reducing the pollutants concentration. After separation, the COD value of the samples was about 50 mg/L. and the values of (SS) and the oil and grease concentration were about 110 and 80 mg/L respectively. The result of the study also showed that the cooling water can be reused in both of material mill and in the clay washing units. Both the quantity and quality of the cooling water are compatible to be reused in these units after separating the oil layer. An detention time of not less than 60 min. was necessary to adjust the SS concentration to be compatible with Iraqi water sources standards.

Abstract:

This paper presents an experimental study of heat transfer between a shallow fluidized bed and the surface of a single horizontal tube and a tube bundle, which is immersed in it.
Carbon, which is prepared from the Date stones, is used as a solid to be fluidized and a compressed air as an external fluid.
The results showed that the overall heat transfer coefficient of tubes bundle, which immersed in fluidized bed is lower than single tube.
The modified correlations and analysis are offered by experimental work, which shows the relations between heat transfer coefficient and superficial mass velocity.

Key word: heat transfer - heat exchangers - fluidized bed heat exchangers

The study concentrates on evaluation of cations concentration in Tigris river within Mosul city. Many samples had been taken from the river during Sept (2000) to Jun (2001), The study revealed that the Calcium ion is the predominant cation followed by Magnesium ion followed by Sodium ion and finally Potassium ion with concentrations of (4, 1.8, 1.3, 0.14) meq/l and percent of (55.9%, 24.8%, 17.4%, 1.9%) for each of them respectively.
The study revealed that there were no valuable variation of actions concentrations along the river stream involved in the study, also the concentration of Calcium, Magnesium and Sodium ions increased in rainy months of the year. The results of this study compared with a study done on Mosul dam lake it showed that there were similarity in seasonal concentration variation between two studies but ions concentrations in the river was higher than there concentration in the lake.
Also the results of this study were compared with the previous study for Tigris river 30 years ago showed that all cations concentration in current study is more than those of previous study except the Magnesium ion stays constant. Concentration of the cations in Tigris river is less than those in ground water on the region by 5.6 time for Calcium, 9.3 times for Magnesium, 14.3 times for Sodium and 11.4 times for Potassium.
Key words: Tigris River, Cations, Calcium ion, Magnesium ion, Sodium ion, Potassium ion.

In the present work the Finite Prism method was used for the dynamic analysis of bridges under moving vehicles. In this method a combination is used of the finite element method representing the cross section of the prism and Fourier series suitably chosen to represent the behavior of prism in the longitudinal direction, which satisfies the simply supported boundary conditions at the ends. Explicit time integration scheme was used for solving the equation of motion for each of the bridge and vehicle. In the present work damping was neglected in the formulation of equation of motion of bridges. These render to avoid the solution of global system of equations, because each equation becomes uncoupled with other equations. One of the main aspect in the present work is the coupling of the explicit solution technique of the equation of motion with the harmonic solution using the finite prism method for the problem of moving vehicle, taking into consideration the dynamic interaction between the vehicle and bridge.
Keywords: Bridge, Dynamic Interaction, Finite Prism, Moving Forces, Moving Vehicles

Abstract
In this study the bentonite clay has been used as a coagulant and coagulant aid with ferrous sulfate in turbidity removal for different initial synthetic turbidity of Tigris River samples of (10- 500) ntu, The study revealed the efficiency of using bentonite clay as a coagulant alone in removing turbidity with a dose not more than 30 mg/l, Also the study reveled the improvement of ferrous sulfate efficiency for removing water turbidity when bentonite clay used with it in a dose of 7.5 mg/l of bentonite and 5 mg/l of ferrous sulfate. The regression analysis showed that the most important variables affecting on turbidity removal were initial turbidity followed by settling time and bentonite clay dose then finally ferrous sulfate dose.
Key Words: Ferrous Sulfate, Iron Salts, Bentonite Clay, Coagulation, flocculation, Coagulant aids, Turbidity removal, Water Supply

In this study a cross-classification technique is used to predict trip production travel among 20 traffic analysis zones located within Dohuk city residential area. Two and three level cross-classification matrices has been used to describe dis- aggregated trip rates/Du, total vehicle trips/Du and total private trips/Du. Car ownership is considered as the main factor causing trip production related to other household characteristics like family size income level and workers number.
Out of this study it is concluded that data can be used directly in the prediction analysis of trip rates. Family size and workers number are the most effective independent variables. Number of cells can be reduced if larger sample size are used in the prediction analysis as well.
Key Word : Cross Classification, Dohuk

The paper shows that the number of vehicles in the country amounts to 3.14 millions, a two- folds compared to the vehicle numbers in the last decade. This huge number emits as much as 17.2 tons of exhaust gasses such as COx, NOx, SOx, lead, and other pollutants. This is equivalent to 40 gm/sq. kilometer of Iraq area. This paper also addresses the adverse consequences of this fast-becoming major problem for physical and mental health. It appears that this sector may lead to 40-100 deaths/10000 vehicle, a value that exceeds the global rate. Vehicles are gluttony consumers of fuel. It is estimated that 71 million liters of fuel are daily burnt in vehicles. This may create odor, thermal pollution, as well as other pollutants. More than 3 million used batteries and 6 million tires are yearly discarded. The fate of these materials is either burnt causing more air pollution or left on land and creating solid waste problems. This sector has other detrimental effects on environment. Noise pollution, tourist activities consequences, and military actions using such vehicles could bring about a detrimental bad impact on the environment. The paper concludes with some steps to be adopted so as to reduce the burden caused by motor vehicle sector on the Iraqi environment.
Keywords: Transportation pollution, Environmental pollution, Pollution.

Abstract
The flow pattern resulting from a circular flume immersed in a rectangular channel is investigated. The circular flume consists of two PVC pipes. The larger diameter pipe is laid horizontally and the smaller pipe is fixed vertically inside it. The presence of the vertical pipe reduces the cross section of flow inside the horizontal pipe, creating a critical-flow condition. A gage is installed at the upstream side of the vertical pipe. The depth reading on the gage is directly related to the flow-rate and hence can be used as a measure for flow-rate. This mobile apparatus can be used on both lined and unlined canals. The circular shape of the flume fits to the natural shape of a furrow, reducing the possibility of lateral flow around the flume and makes it a convenient apparatus for measurement in furrows. The results showed variations between the real and the calculated flow-rates. These variations were due to the effect of streamlines curvature and were between 0.9% to 12.1%. Calibration equation of the flow-rate correction factor was developed taking into account the streamlines curvature effect.
Keywords: water measurement, flow measurement, canal discharge.

Abstract
The relationship between water quality characteristics and spectrum photometric properties of water was investigated. Different sample types were taken to conduct the study (well, river, wastewater and synthetic samples). Chemical properties of samples were tested in addition to the absorbance of filtered samples at a range of visible and UV wavelength (200-220-300) and (400-500-700-1000) ηm. The work showed that there are significant effects of the quality parameters on the absorbance at a selected wavelength i.e. for well samples; nitrate, sulfate and chloride can be estimated with an acceptable precision through the absorbance at selected wavelengths. Furthermore organic, Nitrate and Alkalinity in the wastewater can be estimated via the absorbance measuring at a selected wavelength for the filtered samples. The same way can be followed for river samples. Finally, this work may be beginning of new aspects of a water quality monitoring that brings a great benefits and easy ways to those working with this field in the site or even in the lab.
Keywords; Water quality, spectrophotometer, characteristics, well, river, wastewater.

ABSTRACT

High elevations of groundwater at Mosul city is a very big problem and may cause mass destructions to the environment, health and building foundations due to the closing of groundwater near ground surface. From field investigations for 43 large diameter shallow wells, the water elevations were measured 14 times through 7 months. Utilizing raster based GIS operations with automated parameter estimation (PEST), the conceptual model was build and converted to numerical model. The hydraulic conductivity values have been found after model calibration. The elevations, path lines and flow vectors maps were drawn from model results. Three sectors for groundwater elevations in the city have been defined and introduced to the water management agency for prompt decisions. The distributed finite-difference flow code (MODFLOW) selected in this study has approved to be a useful tool for creating a groundwater flow model for the study area. The results of the model can be used for the sewerage net design in Mosul city also for the planning of the agriculture and industrial projects.

Keywords: Groundwater; Mosul city; Environment; Modeling.

Abstract:

The boundary equations of different flow cases for compound hydraulic structure have been found in this paper. A weir was fixed under sluice gate in a rectangular flume form a jet of water from the opening between the two structures.
The tail water elevation has been changed gradually from the edge of weir to (25cm) depth from the channel bed. Through the experimental program four flow cases have been formed(A,B,C&D).Case(A) happened when tail water depth (10cm) or less (case of free jet), Case (B) happened when tail water depth greater than (10cm) till the edge of the sluice gate, Case (C) happened only when the gate opening was (1cm) and the tail water depth was between(14-15)cm (case of oscillating jet), this case causes severe vibration and must be avoided in design. Finally, case (D) happened when tail water above edge of the gate (case of submerged jet).

Abstract
The demand for images, video sequences and computer animation has increased drastically over the years. This has resulted in image and video compression becoming an important issue in reducing the cost of data storage and transmission time. JPEG is currently the accepted industry standard for still image compression, but alternative methods are also being explored. Fractal Image Compression is one of them. In this paper implementation of fractal compression with quadtree partitioning have been done, this paper also includes a study of the parameters that affect fractal image compression.

Keywords: fractal, compression, quadtree .

Abstract
The present work deals with robust stability analysis and synthesis of Cuk converter circuit .Mathematical model in state space form is developed for the circuit .A general system matrix is derived for the system with perturbations in a chosen elements values in the system. H∞ - design technique is applied to design a feedback controller for the system with its nominal values. A µ - synthesis technique is used to design a controller for the system to guaranty its robust stability .The system with designed controller of the two above techniques, is investigated. It is observed that the controller obtained from µ - synthesis technique guaranties the robustness of the Cuk converter circuit with 25% simultaneous uncertainties in all perturbed elements.
Key wards: Robust Stability, H∞ - Design Technique, µ - Synthesis Technique