Journal of Research in Science, Engineering and Technology

Risk analysis of city gas networks using multi-criteria decision making method and AHP hierarchical analysis

2023-08-30T18:51:03+10:00

Transporting energy carriers through pipelines is one of the most economical methods of transporting natural gas, oil, and petroleum products, which are associated with many risks through road and rail transport fleets. Conducting environmental risk assessment studies is a step in the direction of identifying, analyzing, and classifying risk-generating factors and thus reducing the possibility of adverse consequences and controlling the potential risks of such projects in order to protect the environment. This study has been done with the aim of providing a model to assess the environmental risk of gas transmission projects. In this research, in order to achieve the goal, a combination of the indexing system method and the decision matrix process is proposed. By using this integrated method, it is possible to classify, quantify, and prioritize all kinds of environmental risks in gas transmission pipeline projects based on the determined indicators and criteria. Based on the risk assessment, the results showed that the two failure cases of gas cylinder breakage and network and connection leakage are the most critical failure modes based on risk.

Modeling Unmanned Submarine by an Adaptive Control to Follow an Ellipse Path by Considering Disturbances on the System

2022-12-11T15:34:36+11:00

Recent advances in the robotics industry and the design of controllers in sync with the structure of robots have made it possible to use robotic systems in exploration, information display in human-difficult environments, military, medical, and human life-saving purposes. The accuracy and robustness of the path tracking is essential for the use of robots for such purposes. In this article, the modeling of the underwater robot is done and the adaptive control system is presented to track the path of the robot. Submarine robots have a non-linear dynamic with dynamic and kinematic uncertainties and excess force terms due to the robot's entry into the sea, and the controller designed for the system must be able to overcome these forces and be able to estimate the terms It is required to control the robot so that the control system can use this information to eliminate the effects of the stated uncertain terms. The results showed that the designed control system was able to predict and travel the target path with an error of less than 5% despite the presence of unconventional forces and external disturbances in the model.

Designing and implementing a 3D printer using a microcontroller and evaluating its performance on ABS and PLA materials

2023-09-02T15:43:20+10:00

Three-dimensional (3D) printing is one of the rapid modeling methods which has revolutionized the prototyping industry. 3D printers change thin layers of materials into 3D objects. These printers use a variety of techniques and materials. Still, all of them are capable of converting digital files containing 3D digital data, that is generated by 3D modeling software, into physical objects. These printers are used for various purposes. In this research, a new 3D printer using a micro controller is designed and implemented. To evaluate the performance of the printer on acrylonitrile butadiene styrene (ABS) material and polylactic acid, samples of specific sizes were produced. Then size of the produced samples was measured and the effect of temperature and speed changes on their length, width, thickness, and quality of surface were investigated. Finally, diagrams of size and quality variation towards temperature and speed changes determined the ideal temperature and speed for the two mentioned materials.

Presenting a Suitable Method for Protecting Electromagnetic Field on Rebars of RC Foundation

2022-12-11T16:07:44+11:00

Electrical reactors used in the power industry are equipment that typically includes multiple coils, and a high electric current passes through to about a few kilo amperes. In accordance with the technical specifications, dimensions, structure and physical shape of the equipment, magnetic fields are formed around them. The magnetic field of this equipment can affect the steel structure of the foundation and its retaining reinforcement concrete structures and cause the induction of the voltage of the rotary and stray electrical currents in the rebar mesh and the heat losses and metal components of the reactor foundation. Mechanical stresses caused by generated heat in steel rebars can cause failure, cracks and reduction of reinforced concrete durability. In this research, the reinforced concrete foundation of Tyristor Controlled Reactors by exposed to a low-frequency magnetic field and a relatively large flux density is simulated and analyzed using the ANSYS Workbench software. The amount and distribution of temperature and mechanical stress in the foundation were obtained and the results of software output were compared with the scientific criteria of fraction and failure. Then, four methods were evaluated for constructing a reactor foundation include the use of fiber reinforced polymer rebars, the use of steel rebars by insulation of their contact points with electrical insulating materials, such as polyvinyl chloride, the use of non-magnetic rebar type 304 and the use of Fiber Concrete with cost criteria, time and quality. Based on the results, the method of using steel rebar along with insulating their contact points and considering the electrical and thermal clearance of the reactor is economically feasible and is applicable at a shorter time and is technically acceptable.