Secondary Subsystem Research Articles

Investigation on the integration of supercritical CO2 cycle with natural gas oxy-fuel combustion power plant

The utilization of LNG cold energy is promising to offset the energy penalty of oxy-fuel combustion technology and achieve efficient carbon emissions reduction. In this paper, natural gas oxy-fuel power systems utilizing LNG cold energy are investigated. Supercritical and transcritical CO2 cycles are adopted to deeply recover flue gas waste heat. Results show that the thermal efficiency of the supercritical CO2 recompression cycle is 6% higher than that of the regenerative cycle, whereas the net power output of the recompression cycle is lower. With transcritical CO2 cycle as the secondary subsystem, the efficiency of both integrated systems is enhanced by approximately 9%. Meanwhile, 95% CO2 is captured with the power consumption of 0.07 kWh/kg-CO2. The total investment costs of the integrated regenerative and recompression cycle are 53.96 M$ and 54.62 M$. The levelized cost of electricity of the two integrated systems is 3.21 $/MWh and 3.24 $/MWh, indicating great financial availability. Therefore, applying supercritical and transcritical CO2 cycles contributes to efficient energy conversion and carbon capture. The research could provide meaningful information on the oxy-fuel combustion power system integrated with supercritical and transcritical CO2 cycles from thermodynamic and economic insights.

Seismic robustness computational methodology of community building portfolio coupled with water supply network based on probability‐cloud model

AbstractA novel seismic robustness computational methodology is proposed for community building portfolio (CBP) coupled with lifeline networks based on probability‐cloud model. This method consists of three interrelated submodels, respectively, the building fragility analysis model of the main subsystem CPB, the water supply network (WSN) hydraulic simulation analysis model of the secondary subsystem WSN, and the probability‐cloud model. The proposed method can be used to predict the seismic robustness of hierarchical systems. The computational methodology uses a joint probabilistic model combined with building fragility analysis and WSN hydraulic simulation analysis to evaluate the robustness of CPB coupled with WSN. Due to the uncertainty in robustness analysis, a probabilistic‐cloud model procedure considering the uncertainty in seismic robustness is proposed. The procedure enables a qualitative and quantitative integrated analysis of the robustness of CBP coupled with WSN. Finally, a community with 1406 buildings in China is simulated to illustrate the method. The research outcomes can provide a useful reference for the seismic robustness analysis of CBP coupled with WSN.

PI Stabilizing Control of Nonaffine MIMO Systems by Additive-State-Decomposition Dynamic Inversion Design

This paper addresses the stabilizing control issue for a class of non-affine MIMO (Multiple Input Multiple Output) nonlinear systems subject to time-varying disturbance using an additive-state-decomposition dynamic inversion control scheme. First, the original system is transformed into a minimum phase system through a proposed output redefinition method. Then, the transformed minimum-phase system is further additively decomposed into a primary subsystem and a secondary subsystem. Next, the dynamic inversion control scheme solves the non-affine control problem. Stability analysis shows that the proposed control method guarantees all closed-loop system signals being semi-globally uniformly ultimately bounded. Finally, a simulation and an attitude control experiment of a quadcopter show the effectiveness of the proposed control method.

The concept of preventive care in the pediatric population with risk factors for the malocclusion development and prevention of severe malocclusion in children aged 3-12 years old

Relevance. Malocclusion prevention in Russian children is an urgent medical and social problem. The results of Russian epidemiological studies show malocclusion prevalence and severity increase in children with age. Postgrowth orthodontic treatment is costly and often inaccessible for the most population. In the current situation, malocclusion prevention organization in children is one of the most important tasks of public healthcare.Purpose. To propose and substantiate a new model for the prevention of severe malocclusion in children.Materials and methods. We have created a new conceptual model for the prevention of severe malocclusion in children to develop a methodology that provides unified approaches to malocclusion prevention.Results. The model involves the construction of a two-level system of pediatric preventive care based in the city, municipal multidisciplinary dental clinics. The model novelty is determined by the new concept of the primary prevention of malocclusion and early orthodontic treatment (EOT) processes to prevent severe malocclusion (secondary prevention) as a single system that provides a positive result in maxillofacial development in children. The introduction of a pediatric dentist as an operator and a coordinator of the prevention program implementation into the structure of preventive care for children's malocclusion determines the novelty of the prevention system conceptual model. The proposed conceptual model prioritizes an orthodontist who provides secondary prevention of severe malocclusion by early orthodontic treatment (EOT) to children during the growth and development of malocclusions. The introduction of a malocclusion assessment to identify the EOT need score also determines the novelty of the malocclusion secondary prevention subsystem. The model places a high value on the management function/ management issues. Severe malocclusion prevention program implementation in children requires changing the paradigm of doctors, namely, pediatric dentists and orthodontists.Conclusion. The presented concept of the two-level malocclusion prevention organization (primary prevention of malocclusion in toddlers and preschoolers and secondary prevention of severe malocclusion by EOT in children aged 3-12 years) will allow for the reduction of the number of severe malocclusions during dental and facial development and for the need of complex treatment at later stages, will contribute to children health preservation, their social adaptation and the child and family quality of life increase.

Thermal Management of Hybrid Photovoltaic Systems

Photovoltaic cells can be quite sensitive to the change in temperature, as the entire system’s performance will be affected mainly by an increase in temperature. This is due to the degradation occurring in the solar panel when heat is absorbed, thus producing lesser electricity with the same amount of solar irradiance absorbed. Wind can provide additional cooling on the system; it is too unreliable to consider since wind can come unpredictably. For the design proposed, heat generated is carried away via the water channel underneath each collector’s glass panel. In order to utilize the removed heat, two subsystems are combined to the solar thermal collector. The primary subsystem uses heat to raise the temperature of the hot water storage tank. It can be further heated to the required temperature for the hot water used in the shower. The secondary subsystem consists of an absorption refrigeration system that will provide additional space cooling circulating the house. Based on the available data for maximum solar irradiance, the hot water storage tank can deliver up to 43.8 °C. Additional power of 2.28 kWh is required to raise the temperature to 50 °C. For space cooling, a coefficient of performance of about 2.2 is obtained at maximum solar irradiance. A breakeven point is also estimated to be approximately one year, even though the initial fixed cost for the system is way higher than the installation of conventional products.

Catholic school presence in Latin America: walking heterogenous paths

This study gives an account of the transformation of Catholic Schools in Latin America in the years after the Vatican Council (1970–2015). Mainly, it looks into changes in their enrolment, and more importantly, in how the Catholic primary and secondary educational subsystem has varied in its shared participation within the national education systems of which they are part. By using quantitative methods, this study presents evidence that is significant for understanding the trends followed by Catholic Schools in several Latin American countries, and Latin America as a region. When facing major criticism because of the sexual abuse crisis in the Catholic Church, this evidence may serve the purpose of valuing what this apostolate means and how it needs to change in the future.

Research on Slope Stability Evaluation Based on Improved Set Pair Analysis Method: A Case of Tonglvshan Open‐Pit Mine

In this paper, combined with fuzzy analytic hierarchy process (FAHP), information entropy theory, and set pair analysis (SPA) theory, an improved set pair analysis model (EFAHP‐SPA) for open‐pit mine slope stability evaluation based on entropy method and FAHP is proposed. Taking the east‐side slope of Tonglvshan north open‐pit mine in Daye as an example, the proposed method is verified. First, an open‐pit mine slope stability evaluation index system with 14 indicators in 4 categories, namely the topography and geomorphology, geological structure, hydrogeology, and other factors, have been constructed. Second, the objective weight and subjective weight of each evaluation index are calculated by entropy and fuzzy analytic hierarchy process, and then the comprehensive weight of the evaluation index is estimated based on subjective weight and objective weight. Afterward, the single‐index connection degree between the evaluation index and the evaluation standard of the secondary subsystem is evaluated considering the improved set pair analysis theory, and the comprehensive connection degree of the system is obtained by combining it with the comprehensive weight of each evaluation index. Finally, the confidence criterion is established to discern the risk grade of slope stability in the east‐side slope of the north open pit in Daye Tonglvshan mine. Moreover, case studies and comparisons of the proposed model with fuzzy comprehensive evaluation method and Entropy‐SPA model were performed to confirm the validity and reliability. The results show that the evaluation results of the proposed EFAHP‐SPA model are consistent with the actual situation of open‐pit mines and the evaluation results of entropy‐SPA model and are somewhat different from those of fuzzy comprehensive evaluation method. It indicates that the proposed EFAHP‐SPA evaluation model can objectively evaluate the slope stability of the open‐pit mine.

Optimization design method for urban sewage collection pipe networks.

In this study, a secondary subsystem mathematical model is established under the condition that the layout of the sewage collection branch, trunk, and main pipe network projects is fixed. The sewage collection branch and trunk pipe network projects are treated as the research objective by taking the minimum annual cost of the sewage collection pipe network projects as the objective function, the longitudinal slope of the pipe section and the economic flow rate of the pipe section as constraints, and the diameter of the pipe section as the decision variable. A first-level subsystem mathematical model is established by taking the sewage collection branch, trunk, and main pipe network project as the research object. A large system mathematical model is established in the same manner. This model can be solved using the large system secondary decomposition-dynamic programming aggregation method, and the optimal diameter for each pipe section can be obtained. A regional sewage collection pipe network project in Taizhou city was considered as an example for comparative analysis before and after optimization, and the results verified that the optimization method proposed in this study can solve this complex large system optimization problem.

Numerical study on an original oxy-fuel combustion power plant with efficient utilization of flue gas waste heat

In this work, an original oxy-fuel combustion natural gas power plant with two-stage power generation subsystems is proposed to realize the high-efficiency power generation with low-cost carbon capture. H2O and CO2 derived from flue gas is used as diluent to moderate the high temperature in oxy-fuel system. N2 Brayton cycle as the primary subsystem is utilized to generate electricity from GT exhaust heat. Organic Rankine cycle and transcritical CO2 cycle is used as the secondary subsystem for the low-grade power generation. Accordingly, organic Rankine cycle system and transcritical CO2 cycle system are established and simulated. The cryogenic LNG provides cold energy for the two-stage power generation subsystems and CO2 capture to reduce the power consumption of compression. The numerical results show that when 94.8% of CO2 with 97.2% purity is captured, the power consumption of carbon capture is approximately 0.57 kWh/kg-CO2 and 0.07 kWh/kg-CO2 in O2/CO2 and O2/H2O combustion atmosphere. Transcritical CO2 cycle is revealed to be more efficient for the utilization of flue gas waste heat (including the latent heat of flue gas) than organic Rankine cycle. The net power generation efficiency of transcritical CO2 cycle system is 58.78% in O2/CO2 atmosphere and 54.87% in O2/H2O atmosphere.

Artificial Intelligence via Competitive Learning and Image Analysis for Endometrial Malignancies

Objective of this study is to investigate the potential of an artificial intelligence (AI) technique, based on competitive learning, for the discrimination of benign from malignant endometrial nuclei and lesions. For this purpose, 416 liquid-based cytological smears with histological confirmation were collected, each smear corresponded to one patient. From each smear was extracted nuclear morphometric features by the application of an image analysis system. Subsequently nuclei measurement from 50% of the cases were used to train the AI system to classify each individual nucleus as benign or malignant. The remaining measurement, from the unused 50% of the cases, were used for AI system performance evaluation. Based on the results of nucleus classification the patients were discriminated as having benign or malignant disease by a secondary subsystem specifically trained for this purpose. Based on the results it was conclude that AI based computerized systems have the potential for the classification of both endometrial nuclei and lesions.

Implementation of a ball inverted pendulum with omnidirectional moving ability using a robust fuzzy control strategy

A robust fuzzy controller (RFC) is proposed for a ball inverted pendulum (BIP) system control problem. A Mamdani-type fuzzy controller and a compensated control technique are combined in the proposed control system. This controller is used for real-world control of a BIP with unknown system uncertainties. Using this method, the approximation error caused by the trial-and-error fuzzy control design procedure is minimized. Moreover, the decoupled technique provides a simple method for achieving asymptotic stability control for angle and position of a BIP control system. The concept of this approach is to decouple the entire system into two subsystems. Next, the primary subsystem combines the information provided by the secondary subsystem. And then a control force is generated to drive both subsystems toward their targets, respectively. Thus, the platform can move to any position without constraints. The stability of RFC, which is based on the Lyapunov stability theorem, is guaranteed. Furthermore, to verify the effectiveness of the control algorithm, several numerical simulations and dynamic simulation in the automatic dynamic analysis of mechanical systems (ADAMS) environment with MATLAB are implemented. Finally, the efficiency of the RFC is verified with real-time implementation of the BIP.

Food Insecurity and Odds of High Allostatic Load in Puerto Rican Adults: The Role of Participation in the Supplemental Nutrition Assistance Program During 5 Years of Follow-Up.

Limited evidence demonstrates pathways linking food insecurity (FI) to chronic disease. Allostatic load (AL) may elucidate potential pathways, capturing both primary (neuroendocrine, inflammation) and secondary (metabolic, cardiovascular) physiological disturbances. We examined the longitudinal association of FI with 5-year AL and primary and secondary subsystem dysregulation and tested moderation by Supplemental Nutrition Assistance Program (SNAP) participation. We analyzed data from the longitudinal Boston Puerto Rican Health Study among 733 adults aged 45 to 75 years. Participants categorized as food insecure (assessed by US survey module) experienced FI at baseline and/or year 5. AL score comprised 11 biological components (5 primary, 6 secondary). We classified participants as having high scores for AL (≥6 dysregulated components), primary system (≥3), and secondary system (≥4). Multivariate models estimated odds ratios (OR), adjusting for baseline AL, sociodemographic, cultural, and behavioral characteristics. By study end, 33.8% had experienced FI, 65.5% had participated in SNAP, and 37.5% had high AL. In adjusted models, FI was not associated with AL (OR [95% confidence intervals] = 1.07 [0.70-1.64]) or secondary system (0.82 [0.48-1.40]) scores, but was associated with high primary system scores (1.71 [1.25-2.36]). SNAP participation seemed to moderate the FI-primary system relationship (p = .06); food-insecure participants never receiving SNAP (mean (SE) = 2.06 (0.14)) had higher scores than food-secure participants receiving (1.72 (0.06], p = .02) or never receiving SNAP (1.64 (0.10), p = .01) and food-insecure participants receiving SNAP (1.80 (0.07), p = .08). FI is associated with dysregulated components of the primary AL system, and this relationship may be stronger for those not receiving SNAP. Research is needed in additional populations to test AL as a plausible pathway connecting FI to chronic disease and SNAP as a moderator.

A Systems Approach to Biometrics in the Military Domain.

Forensic biometrics is the application of forensic science principles to physical and behavioral characteristics. Forensic biometrics is a secondary sub-system in the forensic science "system of systems," which describes forensic science as a sub-system in the larger criminal justice, law enforcement, intelligence, and military system. The purpose of this paper is to discuss biometrics in the military domain and integration into the wider forensic science system of systems. The holistic system thinking methodology was applied to the U.S. biometric system to map it to the system of systems framework. The U.S. biometric system is used as a case study to help guide other countries to develop military biometric systems that are integrated and interoperable at the whole-of-government level. The aim is to provide the system of systems framework for agencies to consider for proactive design of biometric systems.

Control of an omnidirectional spherical mobile robot using an adaptive Mamdani-type fuzzy control strategy

In this study, a supervisory control system with an adaptive Mamdani-type fuzzy controller (AMFC) is used to control an omnidirectional spherical mobile robot (ODSMR). The system combines an adaptive Mamdani-type fuzzy controller and a supervisory controller for ODSMRs with unknown external disturbances. Tracking is provided by a Mamdani-type fuzzy controller that approximates a theoretically exact control law, and a separate controller is used to cancel the residual of the approximation error. The control law is derived using Lyapunov stability theory to ensure the stability of the closed-loop system. Many external factors can cause the system to become unstable, so a supervisory controller is included. A decoupled control approach provides a simple method to achieve asymptotic stability for a fourth-order nonlinear system. The main concept of this approach is to decouple the system into two subsystems. Then, the primary subsystem combines the information provided by the secondary subsystem to generate a control that drives both subsystems to their desired states. This platform can move in any direction with no constraints. The efficiency of the proposed controller is verified with tests on an actual robot. The contributions of this study are: (1) the implementation of an ODSMR and (2) the application of the proposed AMFC with a supervisory control system to real-time control of the ODSMR.

Sensitivity Analysis of Carrier Aviation Support System Based on Fuzzy-ANP

System sensitivity is an important basis for carrier aviation support system design and improvement. According to research presented fuzzy network analysis (Fuzzy-ANP) to achieve sensitivity analysis of carrier aviation support system. The first is based on ANP method to establish sensitivity analysis network model of carrier aviation support system, followed by the application of fuzzy theory to determine the weight of sensitivity analysis index, and finally enter specific technical parameters based on secondary subsystem or device of carrier aviation support system, sensitivity analysis, corrected analytical model, proposed carrier aviation support system design suggestions.

Modeling and Control for Max-Plus Systems with Partial Synchronization

A max-plus system with partial synchronization is a persistent discrete event system divided into a main subsystem and a secondary subsystem where some events in the secondary subsystem can only occur when (not after) associated events in the main subsystem occur. A formal model based on max-plus recursive equations is presented for max-plus systems with partial synchronization. Furthermore, the control problem of output tracking is addressed by assigning a higher priority to the main subsystem: the performance of the main subsystem is never degraded to improve the performance of the secondary subsystem. Two different control approaches are investigated: optimal feedforward control and model predictive control. In both cases, residuation theory is applied to efficiently solve the optimization problem.

Power Minimization for Cognitive Relay Networks with Interference-Based Strategy

For the cognitive relay networks, an optimal power allocation algorithm is proposed to minimize the total power consumption, under the promise for the anti-interference performance of the primary subsystem and throughput constraints of the secondary subsystem. An interference-based strategy is presented to use different power allocation methods according to the interferences created by the secondary subsystem to the primary subsystem, comparing with the location-aware strategy in which the channel conditions are considered only with the location information. A kind of computing algorithm joint the subgradient and Newton's methods is also given to resolve the complex optimization problem. The numerical results demonstrate the strength of our proposed schemes.

Availability of k-out-of-n: F Secondary Subsystem with General Repair Time Distribution

In this paper we study the steady state availability of main k-out-of-n: F and secondary subsystems having general repair time distribution. When more than k units of main subsystem fail, then the main subsystem shuts off the secondary subsystem. The life time distributions of the main units and that of secondary subsystem are exponentially distributed. A repair facility having single repairman is facilitated to restore the failed unit. Failure of the main unit shuts off the operation of secondary subsystem, but not vice versa. Failure of the main unit or the secondary subsystem initiates the system shut down. The steady state availability is obtained by solving the linear ordinary differential equations governing the model by using supplementary variable technique.

Time-varying sliding-coefficient-based terminal sliding mode control methods for a class of fourth-order nonlinear systems

This paper presents a decoupled terminal sliding mode control (DTSMC) and a nonsingular decoupled terminal sliding mode control (NDTSMC) method for a class of fourth-order nonlinear systems. First, the nonlinear fourth-order system is decoupled into two (primary and secondary) second-order subsystems. The sliding surface of each subsystem was designed by utilizing time-varying coefficients, which are computed by linear functions derived from the input–output mapping of the one-dimensional fuzzy rule bases. Then the control target of the secondary subsystem was embedded to the primary subsystem by the help of an intermediate signal. Thereafter, the DTSMC and the NDTSMC methods were utilized separately to ensure that both subsystems converge to their equilibrium points. The inverted pendulum system was used in the simulations and results were given to show the effectiveness of the proposed methods. It is seen that the proposed methods exhibit a considerable improvement in terms of a faster dynamic response and lower IAE and ITAE values as compared with the existing decoupled control methods in the literature.

Nonsingular decoupled terminal sliding-mode control for a class of fourth-order nonlinear systems

This paper presents a nonsingular decoupled terminal sliding mode control (NDTSMC) method for a class of fourth-order nonlinear systems. First, the nonlinear fourth-order system is decoupled into two second-order subsystems which are referred to as the primary and secondary subsystems. The sliding surface of each subsystem was designed by utilizing time-varying coefficients which are computed by linear functions derived from the input–output mapping of the one-dimensional fuzzy rule base. Then, the control target of the secondary subsystem was embedded to the primary subsystem by the help of an intermediate signal. Thereafter, a nonsingular terminal sliding mode control (NTSMC) method was utilized to make both subsystems converge to their equilibrium points in finite time. The simulation results on the inverted pendulum system are given to show the effectiveness of the proposed method. It is seen that the proposed method exhibits a considerable improvement in terms of a faster dynamic response and lower IAE and ITAE values as compared with the existing decoupled control methods.