Al-Qadisiyah Journal for Engineering Sciences

Stopband split ring resonator (SSRR) is presented in this paper for measuring the complex permittivity of
liquid with different positions of microfluidic channel operates at a resonant frequency of 1 GHz. The sensor
was fabricated and microfluidic channel is located in the gap groove with two different positions of the
carrier where the electric field is as large as possible. The sensor has been tested with several solvents to
verify its sensitivity where the electric field interacts with the liquid filled in a quartz tube and hence alter
the SRR behavior. The electromagnetic properties (complex permittivity) of the solvent can be extracted
from the shift in the resonant frequency of the resonator due to the perturbation phenomenon.

The natural convection heat transfer has many applications in engineering like solar collectors, cooling of
electronic equipment, and geothermal engineering. The present work demonstrates the recent publications
in the last ten years in this specific subject for a body located in complex shapes like rhombic, wavy,
trapezoidal, elliptical, and Parallelogrammic enclosure. Many parameters like Ra, Nu, number of
undulations, the position of the inner body had been addressed and discussed to draw the main conclusions
and recommendations. It is worthy to mention that a wavy enclosure has been investigated less than the
other simple enclosure shapes due to its complexity. Besides that entropy generation should be included in
future studies in complex shapes of enclosure as this will helps the researchers to extend their studies. The
inner bodies inside trapezoidal, parallelogrammic enclosure are very limited, and more investigation should
be done. The review concluded for the different shapes of enclosure with the tables that illustrate the major
finding of each study. Finally, the governing equations of the natural convection of enclosure filled with
pure fluid, porous medium, and nanofluid had been addressed.

A rotating tubular packed bed electrochemical reactor was used for the electrochemical removal of
cadmium (Cd) from simulated wastewater. Impacts of electrolysis operating parameters: current (0.56–2.8
A), rotation speed (100–500 rpm), initial cadmium concentration (20–100 ppm), and pH (3-9) were
investigated. Response surface methodology and Box-Behnken design were used for optimizing the process
parameters where cadmium Removal Efficiency (RE %) was selected as a response function. Findings of
the present work suggested that currently has a main impact on the removal efficiency of cadmium followed
by rotation speed, then concentration and pH. The results of the regression analysis showed that
experimental data could be fitted to a second-degree polynomial model with value of the determination
coefficient (R2
) equal to 91.8 %. Optimal conditions for process parameters based on the RSM model were
initial Cd concentration of 32.0 ppm, current of 2.8 A, rotation speed of 371 rpm and pH = 3, where a final
cadmium concentration less than 0.3 ppm was obtained after 30 min of electrolysis process (RE= 99.28% ).

The present study, experimentally investigated the mixed convection in a square enclosure partitioned in
two layers. The experiments were performed with Al2O3–water nanofluid (upper layer) and superposed
porous medium (lower layer) with an adiabatic rotating cylinder at the center of the cavity. The boundary
conditions of the experimental study were; the upper and lower walls were assumed adiabatic, the right wall
was heated, and the left wall was cooled. Experimentally, 15 K-type thermocouples and thermal imaging
camera were employed to measure the temperatures distribution inside the cavity when the concentration of
nanoparticles (ɸ = 0.06), the temperature difference (∆T) between the cold and hot walls was (6, 8, and 10)
°C, and angular rotational velocity (-50, -25, 0, 25, and 50) rpm. The results of experimental data showed
that in general, the distribution of temperatures was very well along the upper half of the enclosure, while
in the lower half the temperature distribution was confined near the hot wall region. When the circular
cylinder rotates in counter-clockwise, it noted that the effect of speed is evident in the downside of the
cylinder, while the temperature distribution in the left upper part of the enclosure decreasing. When the
circular cylinder rotates in the clockwise direction, the results showed that the effect of cylinder rotation
was around cylinder only. Moreover, the results demonstrated that the increasing temperature difference
leads to a noticeable increment in the intensity of the flow.

In the last era of the digital revolution, architectural outputs with distinctive void formations appeared.
The development in digital technologies, which adopts solid geometry in the formation of its interfaces.
So the void became an integral part of the design at the level of three dimensions, to serves as a fourth
dimension of architecture. By connecting architecture with the time, the limits of length, width, and height
fade away and change from the limits of place to those of time, and this void shifts out from achieving the
aesthetic needs to achieving functional and structural needs. The direct correlation of the architectural void
with the process of forming the interfaces led it to be considered as a basic architectural formation unit,
and in light of this, the research problem was presented as (insufficient knowledge about the importance
and role of the three-dimensional architectural void and the mechanisms of its formation in the interfaces
of contemporary digital architecture as a void that generates or creates the design within the needs of the
designer and the receiver ). The aim of the research came to reveal the concept of architectural void at the
three-dimensional level, as well as revealing strategies and mechanisms for shaping the void in the
interfaces. The research adopted the descriptive and analytical research methodology in proposing
theoretical knowledge extracted from previous studies of building the theoretical framework for the
geometry terms which contains (strategies for forming digital void, characteristics of void in digital
output, features of digital spatial structure), and applying it on contemporary architectural models with a
qualitative measure that is aimed at knowing the effect of terms on the selected samples and the
percentage of their effectiveness in the characteristics of the digital output, and verifying the main
research hypothesis which stipulated the adoption of the strategy of forming the digital void to combine
the mechanisms of digital formation that is used to create void formation to meet the needs in
contemporary architecture. The results indicated that the disappearance of the boundaries between the
interior and exterior over time led to the use of the void in the formation of the building’s outer mass at the
three-dimensional level so that the formation of the mass is based on that void which is called (designgenerating void) and the structure which is created by the void called (the spatial structure), as its
formation depended on \"geometry\" and its methods of formation

The present paper deals with the electrochemical treatment of wastewaters generated from Al-Diwaniyah
petroleum refinery plant in a batch electrochemical reactor using stainless steel cathode and porous graphite
anode. Effects of operating parameters such as current density (5-25 mA/cm2
), pH (3-9), addition of NaCl
(0-2g/l), and time (20–60 min) on the removal efficiency of chemical oxygen demand (COD) were
investigated. The results revealed that both pH and NaCl addition have the main effect on the COD removal
efficiency confirming that the system was governed by reaction conditions in the bulk of solution not upon
the electro oxidation of chloride ion on the surface of the electrode. Parametric optimization was carried out
using Response Surface Methodology (RSM) combined with Box–Behnken Design (BBD) to maximize the
removal of COD. Under optimized operating conditions of initial pH: 3, current density = 25 mA/cm2
, NaCl
conc. = 2 g/l, and time = 60 min, the removal efficiency of COD was found to be 98.16% with energy
consumption of 9.85 kWh/kgCOD which is relatively lower than the previous works.

This paper presents and validates a numerical model utilizing the nonlinear finite element software
ABAQUS/Standard to simulate the performance and failure of Glass Fibre Reinforced Polymers reinforced
concrete beams under high temperature. A numerical model was firstly developed by selecting the proper
geometrical and material modeling parameters with suitable analysis procedures available in
ABAQUS/Standard. The developed numerical model was verified by comparing numerical results with the
corresponding results of the experimental test extracted from the current study on Glass Fibre reinforced
concrete beams under different elevated temperatures ranges from (20 to 600ºC). Validation results have
indicated the accuracy of the suggested numerical model. The validated numerical model was implemented
to investigate the effect of important parameters on the performance and maximum load of Glass Fibre
reinforced concrete beams under different elevated temperatures that are not considered in the current
experimental tests. These parameters include the effect of exposure time or time-temperature history and
effect of temperature distribution around the beams

Green roofs are a layer that effectively working on blocks of solar radiation from entering the building\'s
structure below partially. Its work as a passive cooling technique, and have the potential to reduce the high
surface temperature of conventional roofs because of the soil thermal resistance, evapotranspiration, and
several effects for foliage shading. This affects the heat flux flow of the roof that in turn influences the
indoor thermal conditions and the building energy demand. The research goals are to test the influence of
the green roof on reducing heat transfer to the interior of heavy structural buildings. The experimental part
was done to examine the effect of the green roof and compare it with a standard roof under influence of
ambient air temperature, solar radiation, and wind speed and test the effect of the green roof on reducing
heat transfer inside the building. The model site was at the Diwanyah city (Latitude: 31.9868 and Longitude:
44.9215), the engineering college campus, Qadisiyah University. The experimental setup includes two
cubicles, with equal internal volume values (163cm * 163cm * 105cm). The experimental results showed
for the period 5-8 September 2019. The maximum zone temperature was 46.4 °C for traditional roof and
37.06 °C for the green roof at 3:24 p.m. The results showed that the maximum internal temperature was
46.97 °C and 36.42 °C for the traditional roof and green roof respectively at 3 p.m. Also, the results for
period 18-21 July 2019 noted that the zone temperature decreased by 7.5 °C and the maximum temperature
of the internal traditional standard roof’s surface is 45.66 °C and 37.41 °C for the green roof.

Mixtures of different types of amine solution Monoethanolamine, Diethanolamine, and Triethanolamine
were experimentally used to investigate the overall mass transfer coefficient (KGa) at different operating
parameters. The experiments were made in a packed bed reactor (PBR) with 75 cm in high and10 cm inside
diameter as a gas-liquid contactor at 25℃ and atmospheric pressure, using a simulation gaseous mixture
(air, carbon dioxide) with recycle stream (semi-continuous process). Experimental design process Taguchi
was employed. Four factors and three levels were chosen and exploded using L9 (3 ^4) orthogonal array
design. These parameters for semi-continuous process were namely: gas flow rate 5,10,and 15 L/min
,airflow rate80,90,and 100 L/h, liquid flow rate 400,450,and 500 mL/min and time absorption time
30,45,and 60min . A Shimadzu GC-8A Gas Chromatograph with a thermal conductivity detector was used
to measure the CO2 concentration absorbed in aqueous blended solution. The maximum value for CO2
loading was 8.622 (mol CO2/mol amine) at 15 L/min gas flow and 450 mL/min liquid flow and 100 L/h
airflow for 60 min from absorption time. The results showed that the max value of KGa is 0.048 S-1
.

This research aims to investigate the literature review on the extraction of algae oil, production of algae
methyl ester (AME) biodiesel and the effect of microalgae biodiesel on the performance, combustion and
exhaust emissions of diesel engine. The study dealt with researchers who published their reports between
2006 and 2020. Researches now concentrate on renewable energy, and biodiesel is one of the renewable
energy sources. Biodiesel is a fuel similar to diesel and has many positive aspects such as quality,
renewable energy, lower exhaust emissions, and greater lubricity. In addition to the use of microalgae in
the production of fuels, they are used in reducing CO2 of the atmosphere which in turn results in better air
quality to breathe and cleaner environment. Many researchers have paid attention to produce biodiesel
derived from microalgae that represents one of the oldest living creatures on the globe. However, by
comparing it with diesel, it has some drawbacks like lower heat content, higher density, viscosity, and
NOx emissions. Optimization strategies are still recommended to fight the side effects of using biodiesel
instead of original diesel fuel.