Development of a model for dimethyl ether non-adiabatic reactors to improve methanol conversion

The modeling of adiabatic and non-adiabatic reactors, using three cooling mediums in the shell side of a shell and tube reactor in cocurrent and countercurrent flow regimes has been conducted. The cooling mediums used in this research are saturated water and methanol feed gas to a reactor which is preheated in the shell side and a special type of oil. The results of adiabatic reactor modeling show good compatibility with the data received from a commercial plant. The results of non-adiabatic reactor modeling showed that more methanol conversion can be achieved in a lower length of reactor, even though in some cases the maximum temperature in the tube side of the reactor is more than the deactivation temperature of the catalyst.     

A novel method for recording the position and orientation of the end effector of a spatial cable-suspended robot and using for closed-loop control

In this paper, a new method of recording the position and orientation of the end effector as a feedback of a spatial cable-suspended robot is presented based on coupling the data of image processing and laser sensors. All of the degrees of freedoms (DOFs) of the end effector can be easily fed back through the proposed protocol in an online way and with the highest accuracy. This method has advantages over encoder feedback method since encoder feedback method does not consider the effect of structural uncertainties like vibrations of the cables. Also, the proposed method is preferable to ultrasonic sensor feedback method or accelerometers, because it does not suffer from the effect of reflecting the sound from obstacles and indoor small room syndrome or the accelerometer noise problems. It is possible to use this setup in almost every environmental situation and for any configuration of the end effector. The position and orientation of the end effector recorded in an online way are used to prepare a feedback signal and control the robot in a closed-loop way using feedback linearization approach. A simulation study is carried out on the ICaSbot which is a spatial cable-suspended robot. Finally, experimental tests are conducted on the ICaSbot to validate the proposed algorithm and simulation results performed in the MATLAB environment.     

Bit pressure control during drilling operation using engineering process control

Proper well control is one of the most important challenges during drilling operations in the oil and gas industry. Engineering Process Control is employed to control bit pressure in the present study. As the main innovation in this study, the reference tracking scenario is utilized for the first time to find the extent to which the controllers can track bit pressure by modifying the reference pressure of different formations in the course of the drilling operation. Overall, the model reference adaptive control is shown to perform better in controlling bit pressure according to some features including the process output tracking criteria, control effort, controller tracking error, and cost functions, in comparison to other controllers.     

Information-Based Node Selection for Joint PCA and Compressive Sensing-Based Data Aggregation

Wireless Personal Communications - Recently it has been shown that when Principal Component Analysis is applied as a dictionary learning technique to Compressive Sensing-based data aggregation,...     

Monitoring and control of bottomhole pressure during surge and swab operations using statistical process control

This article for the first time uses a mixture of Statistical Process Control and Engineering Process Control to identify, monitor and control assignable and common causes during drilling operations. To this end, Control charts are applied on the output of the process controlled using EPC and points outside of the predefined control limits are identified. This method can use controllable input variables not used in EPC such as changes in weight of fluid entering the well, to fully control the process. The results show improvements on limits of EPC method using SPC for controlling bottomhole pressure in the acceptable range.     

Design and manufacturing a torque measurement mechanism for the motors of ICaSbot robot and developing its applications

In this paper, online control of the ICaSbot cable-suspended robot is improved by using the online output of the loadcells. At first, the tension of the cables can be sensed, leading to the evaluation of the required motor torque and consequently resulting in a more accurate motor torque control. Second, the DLCC of the robot can be predefined, which help us not to violate the allowable load to satisfy the acceptable accuracy, and finally the small deflection of cable vibrations can be calculated which results in an even more accurate sensing of the actual position of the end-effector together with the data of the encoders to achieve better feedback and control of the end-effector. This paper presents online recording of the actual cable tension provided using proper data transferring system and the constructed electrical boards which filter the noises. Data acquisition card is used to transfer the data to a computer, and LabView is employed to record and control the robot in an online procedure. Finally, the efficiency of the designed mechanism and the proposed applications are verified by comparing the experimental tests conducted on the IUST cable robot (ICaSbot) with the simulation results using MATLAB software.     

Pulse and direct electrodeposition of Ni–Co/micro and nanosized SiO2 particles

Ni–Co/SiO₂ composite coating was electrodeposited on the steel substrate. The coatings were characterized by X-ray diffraction and scanning electron microscopy. The microhardness of the composite coatings was studied by variation of the electroplating parameters, such as the pulse current (PC) and direct current (DC) electrodeposition methods, deposition temperature, electrolyte pH, concentration of surfactants, sodium dodecyl sulfate (SDS), and cetyltrimethylammonium bromide (CTAB). Zeta potential of SiO₂ particles measurements was performed with various pH, SDS, and CTAB concentrations. The data depict that the hardness of Ni–Co/SiO₂ nanocomposite coatings manufactured by PC electrodeposition increases with the increase of bath temperature, pH, SDS, and CTAB concentration up to 50°C, 4.6, 0.3, and 0.2?g/L, respectively. Beyond mentioned optimum values, the microhardness of nanocomposite coating decreases. Using DC method led to reduce the microhardness. Utilizing SiO₂ microparticles instead of SiO₂ nanoparticles for reinforcing resulted in declining the microhardness. The friction coefficient and wear results demonstrated that using PC method and nanosized particles led to reduce the friction coefficient and increase the resistance to wear. Anodic polarization results illustrated that using SiO₂ nanoparticles and PC method to prepare coating caused corrosion resistance of coating in a 3.5?wt% NaCl solution to enhance.