Dijlah Journal

The predicting of the ultimate axial capacity of concrete-filled steel tube (CFST) columns is essential in the design process. To reach an accurate estimation of the column
capacity it needs to involve all the important parameters that affect the behavior. One
of the most recent tools that has been progressively used for this objective is machine
intelligence. The present study has been dedicated in order to construct an appropriate
artificial neural network (ANN) model that can give accurate predictions to the ultimate
capacity of octagonal concrete-filled steel tube columns. The model is constructed using
a back-propagation and optimizing Levenberg-Marquardt algorithms. The ANN model
depends on experimental data collected from previous researches. To show the reliability
of the model, the results were verified and compared with previous methods presented
in previous researches and codes. The ANN results showed good agreement with experimental ones. The ANN model has been used in exploring various parameters that may
affect the strength of octagonal CFST columns. The results have shown that a careful
portioning of geometrical ad material properties should be followed to achieve the most
.optimum design

The vertical axis wind turbine rotor rotates around vertical axis (VAWT). Its fundamental
benefit is to achieve the ability of receiving the wind from any direction, which is in case
of wind changes. This type of wind turbine does not require the initiation of steering device for deviating rotor to face the wind. The advantage of the use of upstream deflector
for the improvement of the efficiency of a vertical axis wind turbine has been presented
in this paper. A wind turbine scale model has been constructed and tested experimentally.
VAWT design had operated at a reasonably sufficient degree throughout experimental
.tests, even under the sub-optimal conditions
Energy of 1.4 watts was obtained at an air velocity of 3.5 meters / second, this result is
acceptable for an experimental device with dimensions of 50 cm high and 11 cm diameter
.of feather convex and a turbine diameter of 56 cm

Evaporative cooling is considered a cheap method using in many different life applica-
.tions. This type of cooling is suitable for hot and dry regions
The aim of this study is to improve the performance of solar evaporative air cooler by
using new cellulose pad. An ordinary evaporative air cooler (60x60x70) cm, gives (0.39)
m3/s of air was used, it operate in baghdad city using 10 cm thickness of aspen wood
pad and measurement of temperature and humidity was recorded and then the pad was
changed by cellulose, the temperature and humidity was recorded again. After calculation
of humidifying effectiveness of air cooler for two pervious conditions, the results indicate
an improving in humidifying effectiveness by (20,3-58.4)% and (23.6-51.2) % of tem-
.perature difference when using cellulose pad

In this work many experiments were done to remove lead metal ions from contaminated
water. Iraqi mineral clay, montmorillonite is used to adsorb lead ions from contaminated
water using continuous adsorption process. The experiments indicated that 1.0 gram of
the montmorillonite clay can adsorb 22.08, 21.04 and 20.16 mg of lead from their solutions of 10 ppm at the flow rates of 0.03, 0.05 and 0.08 L/min respectively at duration
periods were 2, 3.5 and 6.1 hours. Five grams of montmorillonite clay can adsorb 11.04
liters, 10.5 liters, and 10.08 liters of lead contaminated solution at flow rates of 0.03 L/
min, 0.05 L/min, and 0.08 L/min respectively

Rapid changes of the life in general and the continuous war and conflicts in our country,
imposed great stresses on upcoming generation. University students are important part of
.that generation who deserve help and guide
Some students dropped out or delayed their studying because of different causes among
them is psychological stress. Others are badly influenced in their performance by the
same factor. So, psychological stress is deserved to be studied as a problem of impacts
.students’ performance in college studying
This study is important because excessive levels of academic stress can result in an increased prevalence of psychological and physical problems such as depression, anxiety,
nervousness and stress related to disorder, which in return can affect their academic re-
.sults. Students are thus, seen to be affected by the negative causes of academic stress
:The study tries to answer the following questions as its objective
?a-What is the level of the stress among college students
b-What are the main causes of stresses that influence college students success and fail-
?ures
The study is limited to the students of the Dental Department (third and fourth) stages at
. the Dijlah University College in the academic years 2018-2019
The researchers think that this paper may be valuable to the university students, admin
istrators of the private colleges, parents, related institutions and the Ministry of Higher
.Education and Scientific Research
This research investigates the impact of psychological stresses on private college stu
dents. A questionnaire is conducted to collect research data. A total of 60 questionnaires
were distributed among dental students, third and fourth grades. 56 valid responses are
..obtained