Basrah Journal for Engineering Sciences

Different modulation techniques of Nine-Level Inverter (NLI) for an Open-End Winding Induction Motor (OEWIM) is presented in this paper. The two five-level inverters are fed by both ends of open-winding induction motor. The five-level inverters are connected by cascading of four two-level inverters. This inverter topology does not neutral-point fluctuation so this topology different from neutral-point clamping inverter and this scheme does not the diode clamping to fixed neutral point. In the different multilevel sinusoidal pulse width modulations used for the proposed topology. The drive is implemented and simulation with an open-end winding induction motor and simulation results are presented.

Corrugated plates play an important role in many modern constructions applications. Being the main components like piles or stiffeners means they quite often subjected to high levels of stresses. The presence of flaw or crack in the structure of loaded corrugated plate may lead to the situation of crack growth and then catastrophic failure. Extended Finite Element Method is used to avoid remeshing during crack growth simulation. In order to characterize crack growth in corrugated plate two methods were used which are virtual crack closure method and cohesive segments method. Two case studies were investigated in this study. In the first case the material behavior is assumed to be linear elastic, while in the second one the material behavior is assume to be elastic-plastic. The results obtained using the two methods showed a very good agreement both in linear elastic and elastic plastic cases.

Crow Search Algorithm is an innovative meta-heuristic optimization algorithm. In this paper, chaotic maps are combined into Crow Search Algorithm to increase its global optimization. Ten variant chaotic maps are used and the Tent map is found as the best choices for high dimensional problems. The novel Chaotic Crow Search Algorithm is relied on the substitution of a random location of search space and the awareness parameter of crow with chaotic sequences. The results show that the chaotic maps are able to enhance the performance of the Crow Search Algorithm. Also the novel Chaotic Crow Search Algorithm outperforms the conventional Crow Search Algorithm, first version of Chaotic Crow Search Algorithm, Genetic Algorithm, and Particle Swarm Optimization Algorithm from the point view of speed convergence and the function dimensions.

In this paper, energy and exergy concepts have been carried out on one of the largest gas turbine power plants in Iraq (Rumaila-Basra). Both ISO operating conditions as well as actual operating data recorded for one month in hot season are considered. Results indicate that a lot of heat energy accompanied with remarkable exergy is discharged to the atmosphere. Also, it is found that the combustion chamber has the largest exergy destruction among the plant components. Possibility of cooling the intake air drawn by the compressor and its effects on the plant performance is studied. The required cooling load is found to be in the range 3379 T.R for part load operation to 4723.3 T.R for full load operation. Keywords: Power Plant, Gas Turbine, Energy and Exergy Analysis, EES program.

This work presents a theoretical study on the application of low global warming refrigerants as alternative refrigerant to R 134a in a refrigeration system. The refrigerants investigated are R1234yf, R1234ze, R245fa and R227ea. The performance characteristics of the refrigeration system were predicted using mathematical models running by using EES program under different condenser and evaporator temperatures. The results show that at any working condition the R1234ze give identical performance to R134a and can be used as the best low global warming alternative refrigerant. So the compressor work with R1234ze should be designed with displacement volume more than that of R134a to overcame the reduction in mass flow rate.

Many applications consider floating point arithmetic as a key component of the computations. Combined decimal/binary arithmetic becomes an important topic supports high speed decimal/binary applications. A new 64-bit (16×16 digit) combined decimal/binary multiplier is proposed and implemented in this work that can be used for both fused multiply add (FMA) and multiplier unit. A new partial products reduction tree is shared between decimal and binary multiplier unit. The valuation and comparison result between the proposed multiplier and the previous most recent works shows 4.66 % less delay than combined decimal/binary multiplier and 19.33 % less delay than fastest standalone decimal multiplier.

An-Najaf province considered one of the most important cities in Iraq, which is facing a rapid population growth and continuous development in constructions such as housing, hotels, bridges and shopping malls. Therefore, this study aims to create database for the gypsum content in An-Najaf province (Najaf center and Al-Kufa city). To evaluate the spatial variability of gypsum content, 464 boreholes and in situ tests were selected and analyzed using Geographic Information System (GIS). To achieve that, the adopted method consisted of four steps: (1) data collection; (2) geotechnical data georeferencing; (3) interpolation methods and (4) establishment of maps. Nine geotechnical maps were produced for depths (0, 2, 4, 6, 8, 10, 12, 14, 16, and 35) m. Results showed that the largest part of the study area for the depths from 0-4 m had a gypsum content ranged between 10-25% (moderately gypsiferous), whereas the depths from 4-8 m had a gypsum content ranged between 3-10% (slightly gypsiferous), and the depths from 8-35 m had a gypsum content ranged between 0.3-3% (very slightly gypsiferous). This conclude that the layers from 0-4 m are exceeding the allowed limits (10% gypsum content), which may affect the stability of constructions due to the high levels of groundwater in Najaf province.

Recently, Internet of Thing technology has been used to develop numerous applications, this paper compromising design and implementation of greenhouse prototype that integrated with the IoT to adjust the system’s parameters and monitor the system status from any place in this world.
This system involves three intelligent controllers that designed to stabilize the temperature degree, water level in soil, and light intensity inside the greenhouse prototype structure. These systems have been built by two important parts: the hardware and software.
The hardware part could be achieved by designing and implementing the control circuits, actuators, and install the sensors as well as the devices. The second one is the software part which is involves implementing Fuzzy Inference Engine that represent the system’s brain that monitor and manage the entire process in the system to ensure the best performance. This system has been built to contain three control systems that means there are three different Fuzzy controllers. In order to keep the system practicality, the fuzzy controllers should be aggregated in single code that resides in single microcontroller chip with additional codes that perform the IoT duties.
The proposed IoT system provides the ability for specific people to monitor and manage their systems remotely, using a web application with cloud technology.
The major contributions of the proposed system are started by downloading the controller’s set-points (the desired environmental conditions) from the web page, transfer the set-points to the controllers, and upload data that read from sensors to the same web page.)

In this paper, a neuro-fuzzy network-based adaptive tracking controller is suggested for controlling a type of nonlinear system. Where two neuro-fuzzy networks have been used to learn the system dynamics uncertainty bounds by using Lyapunov method. Then the output of these two networks are used to build a sliding mode controller. The stability of the control system is proved and stable neuro-fuzzy controller parameters adjustment laws are selected using Lyapunov theory. Simulation case study shows that the controlled system tracking the reference model effectively with smooth control effort and robust performance has been achieved.

In the operating of TEG- dehydration unit in Central Rumaila Compression Station. Two operating parameters determine the efficient operating of the unit, the desired dew point depression and the losses of TEG. This work presents an attempt to study the effect of all the operating variables on the efficiency of the dehydration unit such as: the effect of pressure and temperature of the natural gas has to be treated on the water content. Contactor pressure, TEG circulating rate and stripping gas flow rate are also considered in this study. The results showed that decreasing the temperature of the absorber from 130 F to 120 F will reduce the mass fraction of water in the dry gas stream from 0.000076 to 0.00002. Increasing the absorber pressure from 549.7 psia (design pressure) to 600 psia will also reduce the water content in the outlet dry gas from 0.000076 to 0.000022 as mass fraction. The simulation result shows linear relation between the wet gas flow rate from the regeneration column and the lean glycol flow rate.