Category Archives: Master Thesis

Abstract
The integration of Five Generation networks and Wireless Sensor Networks is crucial for the new area of the Internet of Things, which is used for a wide range of applications. Such as: daily living, manufacturing, health care and transportation, etc. Wireless sensor networks consist of small sensor nodes with limited energy. Such nodes have the ability to monitor the physical conditions and communicate information among the nodes without the requirement of the transmission medium. Wireless Sensor Networks are autonomous and are distributed in space. Due to the absence of central authority and random deployment of nodes in the network, Wireless Sensor Network is prone to security threats.
Wireless Sensor Network are vulnerable to so many network layer attacks such as wormhole and replay attacks. Also, Energy conservation is critical in Wireless Sensor Network because the main source of power for sensor nodes is battery with a limited energy. It cannot be easily replaced or recharged. Therefore, power saving is essential to increase the lifetime of sensor nodes. Attackers compromise the internal sensor nodes from which they launch attacks. By sending malicious information, attackers may decrease the sensor nodes’ lifetime from years to days and have a severe impact on the energy of the sensor network. Therefore, The larger amount of energy consumed by sensor nodes during the illegal packet transmission by the attackers. Our work proposed a Detect and Compare Packet Nonce (DCPN) algorithm and Packet Count Detection (PCD) algorithm for Wireless Sensor Networks. These algorithms efficiently identify and isolate attacks like wormhole and replay while avoiding possible service degradation like energy consumption in sensor nodes. The simulation results show that our mechanism can outperform existing techniques in terms of energy consumption and lifetime of sensor nodes. DCNP saves energy by (21.6%) per
X
hour for a wormhole attacks, whereas PCN saves up energy by (12%) per hour for replay attacks, thus increases the lifetime of the sensor node by (19.2%) per hour when using DCPN and by (12%) per hour when using PCD. Finally, the study also shows the temperature monitoring of some mobile sensor nodes. By implementing these algorithms, the temperature of the sensors can be reduced by (10C- 2.50C) per (2.5) minutes.

In this study, a high temperature tribometer machine of pin-on-disc was designed and manufactured to examine the wear characteristics of 2024 and 7075 aluminium alloys at different wear conditions such as temperature, load, and sliding distance. The wear experiments were
carried out in a dry sliding condition at temperatures ranging from 25 to 225 °C, loads of 10, 20, and 30 N, and sliding distances of 1570, 2356, and 3141 m, with constant sliding speed of 2.6 m/s throughout the testing. The results showed that when the temperature increases, the wear due to volume loss also increases. An increase in sliding distance and load increases the wear. The Microscopic analysis and Scanning Electron Microscope (SEM) of the specimens reveals that wear traces are mostly abrasive, with just small traces of adhesive wear visibility. Furthermore, the wear process switched from mild into delamination and subsequently to severe metal wear as the load and temperature continued to increase. Because of the softening impacts of the high operating temperature, the wear mechanism takes the form of massive removal of material in a sliding direction. Due to the higher hardness of Al7075, it has higher wear resistance and lower wear (volume loss) compared to Al2024.

Plants are grown in commercial greenhouses to enhance their quality and protect them from the effects of the natural environment, such as cold, wind and rain. In temperate climes, energy is the highest overhead expense in the production of greenhouse production. Also, the cost of fossil fuels and other traditional energy forms continues to rise. A suitable heating system at a reasonable price is essential for heating the greenhouse to provide optimum indoor conditions throughout the colder months. Flat plate solar collectors (FPSC) are one of the most environmentally friendly and energy-efficient heating solutions. In this work, the thermal performance of the FPSC for the greenhouse heating system was experimentally and numerically investigated by firstly utilizing distilled water as a working fluid and secondly using Al₂O₃-water nanofluid with different nanoparticle concentrations of (0.2wt.%, 0.5wt.%, 1wt.%, and 1.5wt.%) with a mean diameter of 50 nm. The simulation model was conducted using TRNSYS 18. The outcome was validated with experimental results. All configurations were fully modeled in TRNSYS, and experimental tests evaluated the inputs of the model software. As a first step, the study estimates the maximum amount of energy needed, which was 12.8 kW on the coldest day of winter (12^th January 2022) according to the Erbil’s weather data, for a greenhouse located in the Scientific Research Center in Erbil, Iraq. A temperature of 23ºC was selected as the set point temperature in the greenhouse, which is essential for the experiments needed to develop several plants. This investigation followed the ASHRAE standard. The most interesting finding was that when nanofluids were used as a working fluid, the efficiency gain was larger than using water only, even with a low concentration of nanoparticles. The experimental results illustrated that using Al₂O₃-water nanofluid at a concentration of 0.2wt.% increase the collector efficiency by 7.9% compared to water. Furthermore, the simulation results indicate that the maximum collector efficiency was attained, which was 83.6%, when 1wt.% nanofluid was used in the FPSC, which increased the collector efficiency by 26.1% over the water case. Any additional increase in the percentage of nanoparticles reduces collector efficiency. In summary, results show that during the coldest months of the year, the system could raise the inner air temperature of the greenhouse, which is ideal for farming applications and does not pollute the environment. It was also shown that utilizing nanofluid is a profitable working fluid that decreases the cost of heating system. Additionally, adding nanofluid to the system as HTFs could produce and store more energy, which in turn increase energy produced by about 22% over the case of using water only.

Aluminium matrix composites (AMCs), which have better tribological and mechanical properties than other conventional alloys, have a lot of potential for important uses in the automotive, defense, aerospace, marine, agricultural, and nuclear engineering industries. In this work, attempts were made to construct AMCs reinforced with various weight percentages of different reinforcement particles, namely boron carbide (B₄C), titanium diboride (TiB₂), and silicon carbide (SiC), in order to improve the tensile behaviour, hardness, and wear resistance. The reinforcement particles with different weight percentages (1, 3, and 5%) were added to Al6061 using the stir casting technique. This work can be divided into two parts: in the first part, the reinforcement particles were added separately (single-reinforcement composite), while in the second part of this work, hybrid composites (hybrid-reinforcement) were fabricated. The tensile strength, hardness, and wear of the AMCs were investigated. Each experiment was repeated three times to ensure repeatability, and an average was taken. In addition, an optical microscope and a scanning electron microscope were used to characterize the AMCs. The SEM examination shows that the reinforcement particles are distributed evenly throughout the Al6061 matrix. The results of the first part of this investigation show that adding different amounts of TiB₂ and B₄C separately, i.e., as single-reinforcement composite, enhanced the ultimate tensile strength, the composites' hardness, and their wear resistance. The most interesting thing to come out of the data is that adding a small amount of TiB₂ particles increases the hardness of the composites much more than previous research has shown. The results also showed that by adding 1 % wt. of B₄C, and 3 wt.% of TiB₂, the composites had a lower wear rate and higher wear resistance compared to the base alloy. The findings also showed that by adding 5% wt. of SiC, the wear resistance and hardness were enhanced compared with the base alloy. However, 1 % wt. of the particles has a higher ultimate tensile strength.

In the second part of this study, an attempt has been made to fabricate hybrid aluminium matrix composites (Al6061/3% B₄C+TiB₂) at various proportions of TiB₂ (1, 3, 5% wt.). The results showed that (Al6061/3%B₄C+5%TiB₂) has a higher hardness and tensile strength. Due to the porosity in the samples, (Al6061/3%B₄C+1%TiB₂) has a lower wear rate and is more resistant to wear. The most obvious finding to emerge from this study is that adding TiB₂ particles reinforced with Al6061 as a matrix has higher results compared to the other particles that are used.