The growth of carbon nanotubes (CNTs) in a flame requires conditions that are difficult to achieve in a highly heterogeneous environment. Therefore, the analysis of the properties of the reaction ...zone within the flame is critical for the optimal growth of CNTs. In the present study, a comprehensive comparison between the CNT synthesis using a methane diffusion flame and a premixed flame is conducted regarding the morphology and crystallinity of the as-grown nanotubes. The premixed burner configuration created a flame that is stabilized through axisymmetric stagnation flow through sintered metal with one-dimensional geometry, different from a conventional co-flow flame. The significant difference in temperature distribution between the two flames causes a difference in the characteristics of the growth products. In the diffusion flame, the growth is limited to specific regions at certain height-above-burner (HAB) values with a temperature range of 750 to 950 °C at varying radial locations. The identified growth regions at different HAB values showed similar temperature distributions that yield CNTs of similar characteristics. Interestingly, the growth of CNTs in the premixed flame is dictated by only the HAB because the temperature distribution is relatively uniform along the radial directions but significantly different in the vertical direction. 17.3% variation in temperature in the axial direction successfully led to 44% and 66% variation in CNT diameter and crystallinity, respectively. The morphology control capability demonstrated in the present study is important for CNT functionalization for energy storage, nanosensor, and nanocomposite applications, where diameter and crystallinity are influential properties that govern the overall performance of the components.
The Training, Research, Isotopes, General Atomics (TRIGA) research nuclear reactor is utilized in a wide range nuclear applications and has three versions, Mark I, Mark II, and Mark III. The TRIGA ...reactor that is available in Malaysia is a Mark II type, Reaktor TRIGA PUSPATI (RTP). The core power control system in the RTP is designed based on many components including the Feedback Control Algorithm (FCA), and the control rod selection algorithm (CRSA). The CRSA is used in the RTP operation to provide external control to the reactor core reactivity. Even though the CRSA provide stability to the reactor operation, it has relatively complex software structure which produce delayed response time for the control rods selection. Thus, the Single Control Absorbing Rod (SCAR) algorithm is designed to improve the reactor performance by minimizing the time response for the rods selection. However, the SCAR yields a non-constant tracking performance due to the highly non-linear dynamic of the control rods. Thus, to compensate the drawbacks of the SCAR with the existing FCA controller, a hybrid controller is proposed based on the integration of a linear model predictive control (MPC) and Proportional (P) controller named as Hybrid MPC-P-SCAR. The MPC application in the SCAR enable the controller to handle multiple constraints through built-in prediction ability to select the best sequence of future control rod velocity during transient state. Whereas at the steady-state, the MPC is optimized by a scheduled P control switches within the allowable range of power variation. The performance of the proposed Hybrid MPC-P-SCAR, the MPC-SCAR and the existing Feedback Control Algorithm with SCAR (FCA-SCAR) is compared via simulation and evaluated in terms of tracking performance, workload of the control rod drive mechanism (CRDM), and the offset elimination in the unmeasured disturbance. Overall, the Hybrid MPC-P-SCAR controller reduces the settling time by 45% and the steady-state error by 61% of the nominal value compared to the FCA-SCAR.
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•The Hybrid MPC-P core power control is developed via System ID to closely represent the actual plant dynamics.•The experimental work is presented to demonstrate the capability of the SCAR in improving the reactor control performance.•The Hybrid MPC-P is designed to handle multiple safety parameter constraints with direct switching model.•The Hybrid MPC-P can provide constant tracking performance and guarantee plant stability during operation.
Early catalyst deactivation through the encapsulation of catalyst nanoparticles by amorphous carbon layer due to the oversupply of carbon source is one of the key elements that inhibit efficient ...carbon nanotubes (CNT) synthesis in flame environment. The present study utilizes methane diffusion flame with water vapor additive to analyze the effectiveness of the novel water-assisted synthesis of CNT in reducing amorphous carbon formation. Flame shape, temperature, and CNT growth region within the water-assisted flame were analyzed at varying fuel and oxygen concentration. The amorphous carbon layer thickness (ACLT) is analyzed through cross-sectional analysis of the CNT growth region using a developed bend wire method. A 50% increase in fuel concentration results in the increase in axial extent of the growth region by 37.5% followed by an increase in the ACLT by 20%. Meanwhile, an 8% increase in oxygen concentration results in the decrease of growth region axial extent by 82% with a 35% reduction in ACLT. On average, water vapor additive produces an additional 17.3% reduction in ACLT in any flame composition. Both the reduction in ACLT as oxygen and water concentration is independently increased happen due to the carbon supply regulation. However, since the change in the growth temperature that happens at varying oxygen concentration is not observed at varying water concentration, the carbon supply regulation in both situations is remarkably different as explained by the water-gas shift reaction.
Abstract
At present, the power tracking performance of nuclear Reaktor TRIGA PUSPATI (RTP) is considered unsatisfactory performance due to relatively long settling time during transient and a ...chattering noise during steady-state power output. Application of the conventional Feedback Control Algorithm (FCA) as a power control technique is proven to be inadequate to keep the core power output stable and within tight multiple parameter constraints for the safety demand of the RTP. Hence, the present study proposed a multipronged core power control strategy improvement through manipulation of the current Control Rod Selection Algorithm (CRSA), Control Rod Speed Design (CRSD), and Power Change Rate Constraint (PCRC) which are part of the core power control design. In this paper, the profiling and analysis of the multipronged core power control strategy are presented. The model for core power control consists of mathematical models of the reactor core, FCA controller, and a series of multipronged models. The mathematical models of the reactor core are based on the point kinetics model, thermal-hydraulic model, and reactivity model. The reactor model is integrated with the FCA controller and a combination of CRSA-CRSD-PCRC models. The power tracking performance of the proposed control strategy and conventional FCA is compared via computer simulation. Overall, the results show the multipronged FCA offers a wider options for optimum operation of the TRIGA reactor.
Knowledge Graph Fusion for Maintenance Management in Cement Production Hannah Mohd Yusof, Nurul; Adilla Mohd Subha, Nurul; Hamzah, Norikhwan ...
2024 IEEE International Conference on Industry 4.0, Artificial Intelligence, and Communications Technology (IAICT),
2024-July-4
Conference Proceeding
Valuable operation and maintenance management data requires efficient utilization method to enhance operation of the manufacturing system. This paper constructs a knowledge graph database on Neo4j ...for textual and numerical data fusion of a cement production line using actual maintenance operational data. The equipment operation and failures data retrieved from the manufacturing line are structured into two distinct files of textual and numerical data sets. Then, the nodes and the attribute relations are defined accordingly. Both data sets employ a columnar processing strategy which involves organizing and analyzing data based on columns rather than rows, for optimizing performance and resource utilization. Finally, the unified Neo4j-based knowledge graph and subgraphs are constructed. The research shows feasibility to enhance utilization of industrial data through fusion of textual and numerical data using knowledge graph for an adaptive and responsive manufacturing process.
Commonly, solution for consensus problem with input saturation constraints utilizes a low-gain feedback approach. However, limited work has been done on the effects of weighted coupling gain. Hence, ...this paper studies the effect of a time-varying coupling gain on the convergence time of leader-follower consensus on both cooperative and noncooperative leader. The input of each agent is subjected to saturation. Weighted based time-varying gain are developed and applied for cooperative leader connection and noncooperative leader connection. The weighted gain is determined by the errors between the leader and follower tracking difference calculated via computer simulation. The results show that the proposed time-varying gain algorithm reaches consensus for both cooperative and non-cooperative leaders whereas low-gain was unstable.
This paper proposes a consensus-based control strategy for a Water Distribution System (WDS) which enables the system to continuously supply the demand minimizing the impact of faulty equipment ...within the WDS facilities. The convergence in the control system is achieved by utilizing the concept of cellular automata. Simulation of the system using MATLAB shows the effectiveness of the proposed method with convergence time is achieved on the 7th step. The method proposed in this work is scalable and applicable to any large scale of WDS configurations.
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