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Waste heat is one of the major problems associated with the energy system. This paper discusses an energy, exergy, and emissions approach for the hybrid system by utilizing waste heat to the maximum extent. A thermoelectric generator (TEG) is incorporated to utilize the low-temperature waste heat from a hybrid model of a solid oxide fuel cell (SOFC) and a combined heat and power (CHP) system. SOFC is an electrochemical cell that generates power at high temperatures through an electrochemical reaction. The high-temperature, unutilized fuel leaves the SOFC, which is burned in the afterburner. The afterburner temperature controls the operating temperature of SOFC. Here, three recuperators are used to utilize this high-temperature waste heat to improve the performance of SOFC and simultaneously generate heat power from the water or gas recuperator. TEG is an auxiliary power production technology that converts waste heat into energy. A novel integration of TEG with SOFC–CHP hybrid system to utilize the low temperature waste heat, is employed. The main goal of this study is to analyze a novel SOFC–CHP-TEG hybrid system in terms of its thermodynamics and emissions. A Two stage TEG is integrated with the SOFC–CHP hybrid system. The simulation model of high temperature fuel cell (SOFC) is developed on MATLAB and validated with published results. This study analyses the impact of pressure ratio and afterburner temperature on the performance of SOFC–CHP-TEG. To do this, perform energy and exergy assessments using the principles of the first and second laws of thermodynamics. A novel exergy-based sustainability index with emissions analysis for the proposed SOFC–CHP is presented. The achieved overall energy efficiency is 62.54% at a pressure ratio of 12 and an afterburner temperature of 1000 K. With an increase in pressure ratio and temperature, the level of CO emissions reduces significantly. [Display omitted] • A novel energy exergy for SOFC–CHP-TEG system is presented. • Exergy based performance is compared and achieve 56.62. • Utilization of waste heat via TEG. • Energy efficiency of SOFC–CHP-TEG is 62.54% at rp = 12 and afterburner temperature of 900 K. [ABSTRACT FROM AUTHOR]

Recent advances in renewable energy research have suggested the fuel cell as a promising future energy source. Compared to the conventional power generation process, which has multiple-step conversion, a fuel cell is a single-step conversion process and produces power and sometimes heat. The efficiency of the individual existing conventional system is increased by integrating with fuel cells. The purpose of hybridization is to fulfill the demand and supply of power and heat. This paper starts with the historical development of fuel cell proceed with different categorize of hybrid systems. Discuss the possibilities of integration of existing fuel cell with other existing technologies such as SOFC-PEMFC, FC-CHP, FC-GT-ST, FC-Hybrid Vehicle, FC-PV/Battery. Numerical modeling can be done for each hybrid system considering mass balance, energy-exergy balance. At the end of the paper a discussion on the technical, economical, and commercial challenges and their solutions with future possibilities is presented. [Display omitted] • Study the integration potential of fuel cell with other power generating systems. • Fuel-cell hybrid configurations are analyzed. • Modelling aspect of various fuel cell hybrid configurations were summarized. • Fuel cell behavior with power and heat generation is presented. [ABSTRACT FROM AUTHOR]

This paper contributes a novel sustainability index and modified exergy indicators for conventional gas turbines and solid oxide fuel cell integrated gas turbine (SOFC-GT) hybrid power cycles. In this work, an intercooled gas turbine (Ic-GT) cycle is considered as a base cycle, which gives an additive advantage in lowering the power required for the compressor. Moreover, on SOFC integration with Ic-GT, the qualitative and quantitative performance are examined. Numerical modeling is done using MATLAB and an exclusive comparison has been made based on energy-exergy and sustainability analysis for the system and its components. On comparing the first law efficiency at turbine inlet temperature, TIT 1250K and rp = 18 for Ic-GT, intercooled recuperated gas turbine (Ic-RGT), and Ic–SOFC–RGT, it is 25.82%, 36.04%, and 64.78%, respectively. Similarly, second law efficiency is 11.43%, 22.33%, and 61.11% and the overall sustainability index is 1.12, 1.28, and 2.57 for Ic-GT, Ic-RGT, and Ic–SOFC–RGT, respectively. Nine other modified exergy-based parameters are used to identify the role of fuel and product exergy and then compare the most affected component in three configurations. [Display omitted] • Gas turbine exhaust waste heat has been examined to power fuel cell. • Two typical intercooled gas turbines and a fuel-cell hybrid system are compared. • Energy efficiency, exergy efficiency, sustainability index are compared. • Configurations are compared using nine modified exergetic performance indicators. [ABSTRACT FROM AUTHOR]

In this paper, six novel modified exergy relations are explored to determine the precise estimation of exergy destruction and to identify which component has the most improvement potential. For this, three power generation cycles are considered, i.e., simple gas turbine (SGT), recuperated gas turbine (RGT), are compared with a novel hybrid system (SOFC-RGT: Solid Oxide Fuel Cell-RGT), which operates with fuel flexibility as well as enhanced work-output and thermal efficiency. For energy, exergy, and sustainability studies, numerical modeling is conducted using MATLAB. At r p = 4, TIT = 1250 K, an exclusive comparison has been made between proposed configurations based on thermodynamic modeling and exergy-based sustainability index. It is found that with the inclusion of a recuperator and a fuel cell in the proposed cycles, the thermal and sustainability performance tend to increase significantly. Whereas, exergy destruction increases but has minimal impact on comparing thermal performance and sustainability index. In terms of sustainability, RGT is 30.76% more sustainable than SGT, while SOFC-GT is 63.39% more sustainable than RGT. [Display omitted] • The gas turbine exhaust waste heat generated has been examined for powering the fuel cell. • A comparative sustainable, qualitative and quantitative performance comparison has been made between SGT, RGT and SOFC-RGT. • As per sustainability index the performance order is SGT < RGT < SOFC-RGT (lower to higher). • 6-Modified exergy indicator is used for performance comparison. • A novel performance map has been drawn for SGT, RGT and SOFC-RGT. [ABSTRACT FROM AUTHOR]

This paper presents a novel nonlinear guidance law for an autonomous unmanned aerial vehicle (UAV) that enables it to track any predefined path while taking into account wind effects. The approach involves treating the desired path as the trajectory of the virtual target, which the UAV tracks without relying on knowledge of the path's curvature. This makes the design applicable to paths with varying levels of complexity and smooth curvatures. Additionally, the proposed method draws inspiration from pursuit guidance, known for its simplicity and ease of implementation. Theoretical analysis ensures that the UAV will converge to the intended path within a fixed time, irrespective of its initial configuration relative to the path. Simulations demonstrate the effectiveness of the proposed method, showcasing the UAV's ability to accurately follow diverse curvilinear paths. [ABSTRACT FROM AUTHOR]

• Resistance to artesunate + sulfadoxine-pyrimethamine (AS+SP) has been flagged for Plasmodium falciparum malaria in India. • Meta-analysis on SP-resistance markers in India reveals high likelihood of drug failure. • Malaria genetic surveillance is urgently needed to generate evidence for drug policy change. • 12 states and 58 districts identified as hot spots for surveillance of SP-resistance markers. India is on track to eliminate malaria by 2030 but emerging resistance to first-line antimalarials is a recognised threat. Two instances of rapid development, spread, and natural selection of drug-resistant mutant parasites in India (chloroquine across the country and artesunate + sulfadoxine-pyrimethamine [AS+SP] in the northeastern states) translated into drug policy changes for Plasmodium falciparum malaria in 2010 and 2013, respectively. Considering these rapid changes in the SP drug resistance-conferring mutation profile of P. falciparum , there is a need to systematically monitor the validated mutations in Pfdhfr and Pfdhps genes across India alongside AS+SP therapeutic efficacy studies. There has been no robust, systematic countrywide surveillance reported for these parameters in India, hence the current study was undertaken. Studies that reported data on WHO-validated SP resistance markers in P. falciparum across India from 2008 to January 2023 were included. Five major databases, PubMedⓇ, Web of ScienceTM, ScopusⓇ, EmbaseⓇ, and Google Scholar, were exhaustively searched. Individual and pooled prevalence estimates of mutations were obtained through random- and fixed-effect models. Data were depicted using forest plots created with a 95% confidence interval. The study is registered with PROSPERO (CRD42021236012). A total of 37 publications, and 533 Pfdhfr and 134 Pfdhps National Centre of Biotechnology Information (NCBI) DNA sequences were included from >4000 samples. The study included information from 80 districts, 21 states and 3 union territories (UTs) from India. The two PfDHFR mutations, C59R (62%) and S108N (74%), were the most prevalent mutations (pooled estimates 61% and 71%, respectively) and appeared to be stabilised/fixed. Although rarest overall, the prevalence of I164L was observed to be as high as 32%. The Pf DHFR double mutants were the most prevalent overall (51%; pooled 42%). The prevalence of triple and quadruple mutations was 6% and 5%, respectively, and is an immediate concern for some states. The most prevalent Pf DHPS mutation was A437G (39%), followed by K540E (25%) and A581G (12%). There was a low overall prevalence of Pf DHFR/ Pf DHPS quintuple and sextuple mutations but surveillance for these mutations is critical for some areas. The analyses span the two critical policy changes, highlight the areas of concern, and guide policymakers in strategising and refining the anti-malaria drug policy for malaria elimination. The results of the analyses also highlight the SP-resistance hot spots, critical gaps and challenges, and indicate that focal and local malaria genetic surveillance (including drug-resistance markers) is needed until malaria is successfully eliminated. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract This work targets the problem of leader following consensus in heterogeneous multi-agent systems described by second order nonlinear dynamics. The controller proposed in the study is an event-based sliding mode controller. Synthesis of the controller has been partitioned into two parts– a finite time consensus problem and an event-based control mechanism. In the first part, the leader following heterogeneous multi-agents of second order having inherent nonlinear dynamics have been addressed and a novel sliding mode reaching law based on inverse sine hyperbolic function has been designed to drive the agents towards consensus. In the second part, an event-based implementation of the control law has been incorporated to minimize computational load on the computational device equipped with the agents and reduce energy expenditure. The triggering rule proposed in this work is dynamic and taking samples respecting this rule ascertains that the desired closed-loop performance of the system is not compromised while exhibiting robustness and high efficacy. The advantage of using such a scheme, i.e., an event-based sliding mode controller is rooted in the robustness capabilities of sliding mode controller and reducing computational expenses via event-based mechanisms. Numerical simulations and mathematical foundations confirm the effectuality of the controller proposed in this study. [ABSTRACT FROM AUTHOR]

Continuous Stirred Tank Reactors (CSTR) are the most important and central equipment in many chemical and biochemical industries, that exhibit second order complex nonlinear dynamics. The nonlinear dynamics of CSTR poses many design and control challenges. The proposed controller guarantees a stable closed loop behavior over multiple operating points even in the presence of perturbations and parametric anomalies. An event driven sliding mode control is presented in this work to regulate the temperature and concentration states very close to the equilibrium points of a CSTR. The control is executed only when a predefined condition gets violated and hence, the controller is relaxed when the system is operating under tolerable limits of closed loop performance. A novel dynamic event triggering rule is presented to maintain desired performance with minimum computational cost. The inter event execution time is shown to be lower bounded by a finite positive quantity to exclude Zeno behavior. Sliding mode control (SMC) combined with event triggering scheme retains the inherent robustness of traditional SMC and aids in reducing computational load on the controller involved. Simulation results validate the efficiency of the proposed controller. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel comparison of pine sawdust, poplar sawdust and almond shell for SOFC-GT hybrid system. • Exergy analysis for each component is compared with the three proposed biomass. • Eight modified dimensionless exergy indicator is used for performance comparison. • Pine sawdust has the maximum thermal efficiency of 63.12% at rp = 6 and TIT = 1250 K. Conventional gas turbines (GT) are working with limited fuels and exhibit thermal efficiency between 30 and 40%. This restriction with the fuels and its efficiency range can be improved by adding an electrochemical fuel cell, i.e; a Solid Oxide Fuel Cell (SOFC). This paper proposes three different types of biomasses, including pine sawdust, poplar sawdust, and almond shell, which may all be used to power the novel biomass-fueled solid oxide fuel cell gas turbine (SOFC-GT) presented herein. MATLAB based simulation is used to validate the results of this fuel cell based hybrid cycle performance. Three performance parameters are considered namely, current density (i d), turbine input temperature (TIT), and pressure ratio (rp) to evaluate the performance of the proposed system. For this, energy-exergy approaches based on the first and second law of thermodynamics are used to assess each cycle component as well as the entire system. The sustainability index and environmental impact factor of each component are evaluated using dimensionless modified exergy indicators. With all three of the suggested biomass fuels, the SOFC-GT hybrid system runs most effectively at pressure-ratio of 6 and TIT 1250 K. Pine sawdust (Case-1) exhibits the largest levels of exergy destruction (2653.14 kW), environmental effect (0.91), and the lowest sustainability index (2.09) but it also has the highest levels of thermal efficiency (63.12%). [ABSTRACT FROM AUTHOR]

We propose predefined-time consensus-based cooperative guidance laws for a swarm of interceptors to simultaneously capture a target capable of executing various kinds of motions. Unlike leader-follower cooperative guidance techniques, the swarm of interceptors has no leader and each interceptor executes its own guidance command in a distributive fashion, thus obviating the residency of the mission over a single interceptor. We first design cooperative guidance commands subject to target's mobility, followed by the same when the target is stationary, and also account for interceptors' changing topologies. We further show through rigorous analysis that the proposed cooperative guidance laws guarantee consensus in the interceptors' time-to-go values within a predefined-time. The proposed design allows a feasible time of consensus in time-to-go to be set arbitrarily at will during the design regardless of the interceptors' initial time-to-go values, thereby ensuring a simultaneous target interception. We also demonstrate the efficacy of the proposed design via simulations for interceptors connected over static and dynamic networks. [ABSTRACT FROM AUTHOR]

This work proposes two different cooperative integrated guidance and control schemes for a group of interceptors, each steered by combined effects of canard and tail aerodynamic surfaces, aiming a simultaneous interception of a non-maneuvering target. The first approach is based on a leader-follower framework, in which the time of interception can be prescribed before homing, while the second approach is of a leaderless framework, in which the time of interception is decided during engagement. The proposed integrated guidance and control design for multi-body engagement is carried out under nonlinear settings, with time-to-go formulations that relax the restrictive assumption of interceptors' small heading angles. This facilitates wide applicability of the proposed design in scenarios necessitating large terminal time requirements. In addition to the nonlinearity in kinematics of engagement and interceptors' dynamics, effect of actuators are also considered, making the design suitable for practical implementation. Since canard and tail aerodynamic surfaces have different capabilities, a weighted effort allocation scheme is devised to apportion the total effort in both control surfaces in a suitable manner. Finally, various engagement scenarios have been considered in simulations to substantiate the efficacy of the proposed schemes. [ABSTRACT FROM AUTHOR]

This paper proposes integrated guidance and control design to intercept a target, which may execute various motions, at a pre-specified time of interception. The problem is addressed considering nonlinear engagement kinematics and the interceptor is steered using the combined effects of canard as well as tail configurations (dual-controlled interceptors). Different formulations of time-to-go, without the restrictive assumption of interceptor's small heading angle, have been used in deriving the guidance commands, allowing the proposed strategy to remain effective over a wide range of impact time values. A weighted effort allocation scheme, in canard and tail deflections, has been proposed to generate the required lateral acceleration. The overall design uses sliding mode control owing to its simplicity of design, while a nonlinear finite-time disturbance observer is used to estimate the target's maneuver. Finally, simulations are presented for various target motions, and time-constrained interception with an impaired actuator is also shown, vindicating the efficacy of the proposed technique. [ABSTRACT FROM AUTHOR]

This paper deals with nonsingular guidance and control design for an interceptor, using a decoupled approach, steered by the combined effects of both canard and tail, to intercept a moving but non-maneuvering target at a time specified a priori. First, interceptor's desired lateral acceleration, consisting of nominal and corrective components, is derived using deviated pursuit guidance. While the nominal component is the pursuit guidance law, the corrective component drives the time-to-go error to zero within a finite-time in an optimal manner. Using a desired error dynamics and a meaningful performance index, the lateral acceleration demand is minimized during the transient phase. With exact knowledge of time-to-go and the consideration of nonlinear kinematic model, the proposed design circumvents the errors arising out of any approximations. Interceptor's canard and tail deflection commands are derived using predefined-time convergent sliding mode control, which allows the autopilot to precisely track the commanded lateral acceleration within a time specified during design. Finally, simulations are presented for various cases to demonstrate the efficacy of the proposed design. [ABSTRACT FROM AUTHOR]

The increasing demand for assorted services from extensive wireline and wireless users place a significant burden on the band-limited radio spectrum. To settle the demand, smart reuse and management of the spectrum are necessary. In this contribution, Cognitive Radio being an emerging technology provides a platform to share the same spectrum between Primary Users (licensed) and Secondary Users (unlicensed) for significant improvement in the spectrum efficiency. The coexistence of users for data communications in a band-limited channel calls for a robust congestion controller to maximize throughput. This work presents the design of a robust nonlinear congestion controller based on event-triggered sliding mode for Cognitive Radio Networks. The goal is to maintain desired Quality of Service of the network with optimum bandwidth and resource utilization. The controller has been designed on the notions of sliding mode, better known for its inherent robustness and disturbance rejection capabilities. An event-triggering scheme has been incorporated with the sliding mode for optimum utilization of the available resources. The signal is sampled and control is updated only when a predefined condition gets violated while ensuring acceptable closed-loop behavior of the system. The efficiency of the proposed controllers has been validated using simulations. [ABSTRACT FROM AUTHOR]

Abstract: Bismuth containing crystalline solutions of (1− x)Bi(MgZr)0.5O3–xPbTiO3 (BMZ–PT) and [(BiFeO3) y −(BiMg0.5Zr0.5)1−y ] x −[PbTiO3]1−x (BMZ–BF–PT) have been developed using conventional ceramic technology. X-ray diffraction analysis reveals that both the systems possess a perovskite structure, in which tetragonal to rhombohedral phase transformation appears for x =0.55 in BMZ–PT and y =0.20 in BMZ–BF–PT systems. SEM photographs reveal a uniform grain size distribution in the solid solution matrix with the presence of ferroelectric domains in few of the compositions. Ferroelectric hysteresis (polarization–electric field, P–E) loops reveal that increase in BiFeO3 in BMZ–PT systems results in a decrease in residual polarization of the system with change and distortion in the shape of the (P–E) loops. [Copyright &y& Elsevier]

Highlights • Co-circulation of all four Dengue Virus serotypes in Delhi. • Coinfection of dengue with malaria and chikungunya. • Occurrence of dengue and malaria inversely related. • Post monsoon peak in dengue cases and high vector indices Abstract Objectives To study the epidemiology of dengue with reference to serological, demographic profile, spatio-temporal distribution, vectors, circulating serotypes and coinfections. Methods Demographic data and presenting symptoms of fever cases reporting to the clinic were recorded. Suspected patients were tested for dengue, chikungunya and malaria. Dengue specific RT-PCR was performed to detect circulating DENV serotypes. Vector surveys were carried out to detect Aedes breeding. Results Of the 5536 fever patients tested during 2012 to 2015, 1536 (27.7%) had confirmed dengue. The peak in dengue positivity was observed during September and October. Of the 60 samples analysed, 10 (16.7%) had concurrent infection with multiple dengue serotypes; one of them had all the four serotypes. Coinfection of dengue with malaria and chikungunya was also observed. The occurrence of dengue and malaria was inversely related. Seven percent of the dengue patients required hospitalization. Vector surveys in the draining area revealed Aedes breeding with a high house index. Conclusion Delhi being hyperendemic, the occurrence of concurrent infections with multiple DENV serotypes has become a frequent finding. The study emphasizes the need of epidemiological and entomological surveillance to monitor trends in dengue distribution, seasonal patterns and circulating serotypes to guide dengue control activities. [ABSTRACT FROM AUTHOR]