Preferred Language
Articles
/
joe-3028
OPEN CIRCUIT HEAT EXCHANGER DYNAMICS DURING FLOW REDUCTION TRANSIENT IN THEIR SECONDARY LOOPS
...Show More Authors

An experimental and theoretical analysis was conducted for simulation of open circuit cross flow heat
exchanger dynamics during flow reduction transient in their secondary loops. Finite difference
mathematical model was prepared to cover the heat transfer mechanism between the hot water in the
primary circuit and the cold water in the secondary circuit during transient course. This model takes under
consideration the effect of water heat up in the secondary circuit due to step reduction of its flow on the
physical and thermal properties linked to the parameters that are used for calculation of heat transfer
coefficients on both sides of their tubes. Computer program was prepared for calculation purposes which
cover all the variables that affect such type of transient mechanisms. The effect of the power density in
the primary circuit and the water flow reduction percentage on the average temperature build up of the
water in the primary circuit was investigated. The elapsed time required for the primary circuit average
temperature to reach a steady state value was also calculated. These calculations were supported with
experimental measurements conducted on a standard cross flow heat exchanger apparatus. The
experimental results were compared with the theoretical results for certain power density value at
different flow reduction percentages which show a reliable agreement. This relative agreement was
necessary to consider the mathematical model with certain assurance for calculating transient parameters
for higher power densities that are out of apparatus ranges. The results proved that water average
temperature build up in the primary circuit has sharp tendency when the percentage of flow reduction in
the secondary circuit reach 25% of its nominal values.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Tue Jun 01 2021
Journal Name
Electric Power Systems Research
Electromagnetic transient modeling of form-wound stator coils with stress grading system under PWM excitation
...Show More Authors

The insulation system of a machine coil includes several layers made of materials with different characteristics. The effective insulation design of machine coils, especially in the machine end winding, depends upon an accurate model of the stress grading system. This paper proposes a modeling approach to predict the transient overvoltage, electric field, and heat generation in machine coils with a stress grading system, considering the variation of physical properties in the insulation layers. A non-uniform line model is used to divide the coil in different segments based on material properties and lengths: overhang, stress grading and slot. The cascaded connection of chain matrices is used to connect segments for the representation of the

... Show More
Crossref (5)
Crossref
Publication Date
Wed Dec 14 2016
Journal Name
Journal Of Baghdad College Of Dentistry
Assessment of Salivary α-amylase and Flow Rate Levels and Their Correlation with Gingivitis and Severity of Chronic Periodontitis (Part: 1)
...Show More Authors

Background: Periodontal diseases are bacterial infections of the gingiva, bone and attachment fibers that support the teeth and hold them in the jaw. α-amylase is an enzyme, produced mainly by parotid gland and it seems to play a role in maintaining mucosal immunity. Aims of the study: Determine the salivary levels of α-Amylase and flow rate and their correlations with clinical periodontal parameters(Plaque Index , Gingival Index , Bleeding on Probing , Probing Pocket Depth , and Clinical Attachment Level ) and the correlation between α-Amylase with flow rate of study groups that consist of ( patients had gingivitis and patients had chronic periodontitis with different severities(mild ,moderate ,severe) and control group . Ma

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Sun Nov 01 2015
Journal Name
Journal Of Engineering
Numerical Simulation of Flow in Rectangular Duct with Different Obstruction Heights
...Show More Authors

       In this study, a simulation model inside a channel of rectangular section with high of (0.16 m) containing two rectangular obstruction plates were aligned variable heights normal to the direction of flow, use six model of the obstructions height of (0.059, 0.066, 0.073, 0.08 and 0.087 m) were compared with the flow behavior of the same duct without obstructions. To predict the velocity profile, pressure distribution, pressure coefficient and turbulence kinetic energy flow of air, the differential equations which describe the flow were approximated by the finite volumes method for two dimensional, by using commercial software package (FLUENT) with standard of k-ε model two dimensions turbulence flow.

... Show More
View Publication Preview PDF
Publication Date
Tue Jul 11 2023
Journal Name
Journal Of Educational And Psychological Researches
Detecting Suicidal Tendencies among Secondary School Students
...Show More Authors

The current research aims to detect the level of suicidal tendencies among secondary school students in terms of gender and educational stage (intermediate school students and high school students). The researcher adopted Al Hafeez's (2017) scale for suicidal tendencies, it consists of (57) items including six domains, namely: suicidal ideation, social motives for suicide, tendency to self-harm, desire for death, indifference and pessimism about life, willingness to commit suicide. The scale was modified to be (42) items after it was exposed to a group of experts. The scale was applied to a sample of (200) male and female students from secondary schools in Baghdad Governorate (Karkh - Rusafa) for the academic year 2021-2022. The results

... Show More
View Publication Preview PDF
Publication Date
Wed Jan 01 2020
Journal Name
International Conference Of Numerical Analysis And Applied Mathematics Icnaam 2019
Prevalence of gastrointestinal parasites in Iraq during 2015
...Show More Authors

View Publication
Scopus (10)
Crossref (5)
Scopus Clarivate Crossref
Publication Date
Mon Jan 01 2024
Journal Name
Fifth International Conference On Applied Sciences: Icas2023
A modified Mobilenetv2 architecture for fire detection systems in open areas by deep learning
...Show More Authors

This research describes a new model inspired by Mobilenetv2 that was trained on a very diverse dataset. The goal is to enable fire detection in open areas to replace physical sensor-based fire detectors and reduce false alarms of fires, to achieve the lowest losses in open areas via deep learning. A diverse fire dataset was created that combines images and videos from several sources. In addition, another self-made data set was taken from the farms of the holy shrine of Al-Hussainiya in the city of Karbala. After that, the model was trained with the collected dataset. The test accuracy of the fire dataset that was trained with the new model reached 98.87%.

Scopus Crossref
Publication Date
Mon Aug 01 2011
Journal Name
Journal Of Engineering
NATURAL CONVECTION HEAT TRANSFER IN AN INCLINED CIRCULAR CYLINDER
...Show More Authors

Experiments were carried out to investigate natural convection heat transfer in an inclined uniformly heated circular cylinder . The effects of surface heat flux and angle of inclination on the temperature and local Nusselt number variations along the cylinder surface are discussed . The investigation covers heat flux range from 92 W/m² to 487 W/m², and angles of inclination 0° ( horizontal) , 30° , 60° and 90° (vertical) . Results show an increase in the natural convection as heat flux increases and as angle of inclination moves from vertical to horizontal position. An empirical equation of average Nusselt number as a function of Rayliegh number was deduced for each angle of inclination .

View Publication Preview PDF
Crossref
Publication Date
Thu Dec 01 2016
Journal Name
Journal Of Engineering
A Laboratory Study Attempt of Flow and Energy Dissipation in Stepped Spillways
...Show More Authors

A new laboratory study conducted on stepped spillways in order to investigate their efficiency of dissipating flow energy. All previous study on stepped spillway indicated that the flow energy dissipation decreased as increasing in discharge. Increasing in the step numbers and the spillway slope led to energy dissipation decrease. In this study, an experimental attempt to increase energy dissipation at variable discharges was performed on stepped spillway and that leads to decreasing the cost of initiating the stilling basin or may be ignoring it. Five spillways were constructed from concrete and tested to investigate and compare among them. Three were roughed by gravel with different size for each one, one of them was s

... Show More
View Publication Preview PDF
Publication Date
Sat Jun 30 2007
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Predicting of Temperature Distribution in Direct Contact Heat Transfer
...Show More Authors

An experimental and theoretical investigation of three phase direct contact heat transfer by evaporation of refrigerant drops in an immiscible liquid has been carried out. Refrigerant Rl2 and R134a were used for the dispersed phase, while water and brine were the immiscible continuous phase. A numerical analysis is presented to predict the temperature distribution throughout the circular test column radially and axially is achieved. Experimental measurements of the temperature distribution have been compared with the numerical results and are discussed .A comparison between the experimental and theoretical results showed acceptable agreement and applicability of the derived equations. Comparison with other related work showed similar beh

... Show More
View Publication Preview PDF
Publication Date
Sun Apr 01 2012
Journal Name
American Journal Of Applied Sciences
A New Strategy for Signaling Overhead Reduction in the Proxy Mobile IPv6 Protocol
...Show More Authors

View Publication
Scopus (5)
Crossref (1)
Scopus Crossref