Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : temperature


Nitrogen Compounds Distribution in Diyala River Opposite Al-Rustimiyah Sewage Treatment Plants

Adnan A. Al-Samawi; Safaa N. H. Al-Hussaini

Engineering and Technology Journal, 2016, Volume 34, Issue 15, Pages 2971-2981

The reach of Diyala River just before its confluence with Tigris River south of the capital city Baghdad was taken as a case-study. This segment of Diyala River is exposed to multiple points of treated and raw municipal wastewater discharges of Al-Rustimiyah wastewater treatment plants. Its pollution status was assessed with regard to nitrogen compounds levels.
The aquatic parameters: DO, TN, TKN NH4-N, NH3-N, NO3-N, NO2-N, pH, and temperature were monitored and measured at nine sites along the river reach for a period of one year to assess seasonal variations. The first and last sites were chosen at the downstream and upstream of the points of pollution flowing into Diyala River, while the second to eighth sites were located at the effluents of the WWTPs of Al-Rustimiyah. It was found that water at sites two, seven, and four, respectively, were the most polluted points among all duo to the presence of the bypasses from the WWTPs at these sites.
With regard to NH4-N, NH3-N, and TN concentrations, the river was found to be heavily polluted with untreated wastewater at site two and between low to medium strength at other sites, except for site one. On the other hand, NO3-N and NO2-N concentrations categorized the river water as an effluent rather than a stream according to Iraqi standard classification.
Reversed relations were found between the DO concentrations and some of the nitrogen compounds and temperature. A statistical model relating TN concentration to DO, NH3-N, and temperature was derived. It was proved to be accurate.

A Finite Element Model for Rutting Prediction of Flexible Pavement Considering Temperature Effect

Mohammed Salih Abd-Ali

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 537-548

Permanent deformation in asphalt layers which manifestation on pavement surface is named rutting which represents one of the most significant distress of asphalt pavements. Different empirical models have been used to calculate permanent deformations which include traffic conditions and temperature effect. These empirical models were calibrated in a three dimensional finite element commercial software package. Finite element analysis through ANSYS computer software (version 11.0) was used to analyze three dimensional pavement structures and in order to investigate the impact of wheel load on rutting formation and pavement response considering temperature effect. In that model, the asphalt layer was assumed to follow a viscoelastic behavior by depending on dynamic modulus using Timm and Newcomb model. While, granular and subgrade layers were presented as linear-elastic perfectly plastic based on Drucker-Prager model. After insuring the model validation, the study investigated the effect of temperature on the rutting depth and plastic strain as a pavement response. The analysis of results showed that the rut depth and plastic strain increases with increasing the temperature.

Total Suction Measurement of Unsaturated Artificial Gypsified Soil Using the Chilled-Mirror Hygrometer Technique

Qasim A.J. Al-Obaidi; Tom Schanz

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 359-374

Total suction is the sum of the matric and the osmotic suction of the soil. Various methods are used to measure the total suction of the soil. One of the methods is the chilled–mirror hygrometer technique. The chilled-mirror device employs a dew-point procedure, which is one of the most accurate and valuable methods for measuring total suction in the mid- to high- total suction range.
The effect of the percentage of gypsum on the total suction estimation for a gypsum-sand mixture has been investigated rarely in the past. In this paper, the total suction is determined for soil specimens containing different percentages of gypsum additive mixed with Silber sand. The soil specimens were prepared at different initial conditions of density and degree of saturation in order to investigate a wide range of physical soil properties. The test results showed that an incremental increase in the percentage of gypsum and degree of saturation of a soil mixture caused a reduction in the measured value of total suction, while an increase in the initial dry density caused the measured total suction to remain almost unchanged. No constant trend is observed with respect to the effect of the curing time on the measured total suction.

Thermal Analysis of High Performance Lightweight Concrete Sandwich Panels

Wasan I. Khalil; Zain A. Raouf; Husain M.Husain

Engineering and Technology Journal, 2010, Volume 28, Issue 21, Pages 6439-6457

This work is concerned with experimental and finite element investigation to determine the temperature distribution in hot weather through the section of the high performance lightweight concrete sandwich panels. In the experimental work thermal conductivity of unreinforced mortar, reinforced mortar and polystyrene concrete were
investigated, then the thermal conductivity of eight series of 1000mm length and 200mm width concrete sandwich panels with two reinforced mortar faces of 20 mm in thickness and core of 30 and 50mm in thickness from polystyrene concrete were calculated. A nonlinear one – dimensional finite element analysis has been used to conduct an analytical investigation on the temperature distribution through the section of concrete sandwich panels. ANSYS (version 8) computer programme was utilized and 2-node LINK elements were used.
The experimental results show that thermal conductivity of the concrete sandwich panels is low with average value of 0.446 W/m.K and the thermal conductivity of the panels with similar type and volume content of reinforcement decreases by about 17% when the core thickness increases from 30 to 50 mm. The finite element results of
temperature distribution show good agreement with the experimental measurements.

Modeling the Effect of Operation Temperature on Characteristics of Rosen Type Piezoelectric Transformer

Nabil N. Rammo; Rajaa R. Abbas; Talib R. Abbas; Inmar N. Ghazi

Engineering and Technology Journal, 2010, Volume 28, Issue 20, Pages 6074-6083

A simplified lumped model that makes direct correlation between Rosen's
piezoelectric transformer (PT) dimensions and material properties via equivalent
circuit parameters was studied. The model calculation of the resonance
characteristics and voltage gain was associated with changes in operating
temperatures from 50°C to 70°C. It is found that for different load resistors, the
resonance frequencies are shifted by less than 1.6% their normal values upon
raising the operation temperature to 70°C, whereas the sensitivity of voltage gain
is better at higher load resistors.
Each of the elastic compliances SE
11, SE
33 and SD
33 of the PT material due to their
temperature dependency cause the resonance frequency to shift below and above
the normal value by less than 1% for very slight change in voltage gain in each
case. The overall balance between mechanical parameters may play role in the
optimum stability of the voltage gain.

Evaluation of Horizontal Flow Roughing Filtration Performance

Zainab S. Habeeb; Sataa A. Al-Bayati

Engineering and Technology Journal, 2009, Volume 27, Issue 15, Pages 2863-2878

The HRF was studied by using pilot plant. This pilot plant was designed
and applied in Al – Wehda Water Treatment Plant which treats the raw water of Tigris River in Al – Karradah in Baghdad city. Design characteristics of the pilot HRF are 5.5m length × 1m width × 1m depth , the HRF length consists of inlet ( 0.5 m ) , outlet ( 0.5 m ) and three compartments ( 2m , 1.5m and 1m ) filled with three different size of gravel ( 15mm , 10mm and 5mm ) respectively . The HRF was continuously operated (24 h in a day) during the period from 15/
May / 2007 to 15/ July / 2007. Operated done in two stages. In the first stage, raw water (free from any addition) was used, with three different flow rate 1.3, 1.1 and 0.9 m3/h. While in the second stage, coagulated water (raw water + alum) was used, with flow rate 1.3 m3/h. To assess the performance of HRF, the required tests were carried out. These tests are Turbidity, S.S, Temperature, pH and Bacteriological tests. The results of tests were analyzed statistically. The mean of
removal efficiency of turbidity for first stage with discharges 1.3 , 1.1 and 0.9 m3/h is 92% , 94% and 95% respectively , and for second stage is 97% . These results indicate the high performance of HRF in turbidity removal.