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• TPV efficient up to 56%. • TES is best for energy storage. • $920/kW-year arbitrage. A hybrid thermophotovoltaic system for thermal-to-electrical energy conversion is a solid-state technique that exclusively utilizes infrared light. However, it faces an upper limit on its conversion efficiency. In this study, its performance is enhanced by integrating concentrated solar energy and a thermal battery. A surface-to-surface radiative analysis in COMSOL is conducted to determine the thermal-to-electrical conversion efficiency. In addition to photon recycling, facilitated by spectral filters, the cells' junction is externally biased to impart a positive photonic chemical potential. This enhances the spectral intensity due to a higher apparent temperature and an increased entropy content. Consequently, it raises the thermal-to-electric energy conversion efficiency to 49% in a real-world scenario and up to 56% in an ideal case. Arbitrage is introduced into this power plant by incorporating an electric grid heater in the system, which bypasses solar heating. It stores electric energy during off-peak hours and provides it during on-peak hours. In this research, financial analysis is carried out using GAMS, and an estimated arbitrage of up to $920/kW-year is achieved from the electricity grid in Pennsylvania, New Jersey, and Maryland (PJM). The thermal battery in the system is also compared with other energy storage devices, proving it to be advantageous compared to Li-Ion and lead-acid batteries, which exhibit higher unit energy storage and conversion costs. [ABSTRACT FROM AUTHOR]

This research paper presents stand-alone and grid-tied micro-inverters for Photo Voltaic (PV) applications. It also addresses several key technical control related issues in the domain of micro-inverter technology for PVs. One portion of this research deals with the digital control strategies for micro-inverters. One Sampling Ahead Preview (OSAP) control has been used to track sinusoidal ac voltage/current of micro-inverters. Microinverter is controlled and analyzed in stand-alone and grid-tied states of operation. In each state, initially the OSAP controller is applied and inverter performance is analyzed. An improved OSAP controller (conventional OSAP + digital resonant controller) is also then applied to compensate the drawbacks of OSAP alone and better track the reference signal. Simulation results are provided which confirm the effectiveness of the proposed control for micro-inverter based solar systems. Another contribution is performance analysis of the proposed control scheme with a Maximum Power Point Tracking (MPPT) strategy. Atmospheric conditions being one of the most influential and uncontrollable factor in solar generation, vary the output of the solar panel nonlinearly. MPPT techniques enable PV panels to operate at the optimal power point and hence generate maximum power. Therefore, various MPPT strategies were considered, and finally an improved variable step size P&O MPPT strategy is used in this research work. Simulation results are given to demonstrate the validity of P&O MPPT strategy along with the proposed control scheme in the events of step changes in irradiation and ac current. [ABSTRACT FROM AUTHOR]

In this work, discriminant analysis is used as the main approach for building a physics based automated classifier for the discrimination of the edge-localized mode (ELM) plasma instability. The classifier is then applied for distinguishing type I and type III ELMs from a set of carbon-wall plasmas at JET. This provides a fast, standardized classification of ELM types which is expected to significantly reduce the effort of ELM experts in identifying ELM types. Further, the classifier yields a separation hyperplane in terms of global plasma parameters, which provides an insight into the range of conditions under which specific ELM behaviors occur. [ABSTRACT FROM AUTHOR]

Characterization and control of plasma instabilities known as edge-localized modes (ELMs) is crucial for the operation of fusion reactors. Recently, machine learning methods have demonstrated good potential in making useful inferences from stochastic fusion data sets. However, traditional classification methods do not offer an inherent estimate of the goodness of their prediction. In this paper, a distance-based conformal predictor classifier integrated with a geometric-probabilistic framework is presented. The first benefit of the approach lies in its comprehensive treatment of highly stochastic fusion data sets, by modeling the measurements with probability distributions in a metric space. This enables calculation of a natural distance measure between probability distributions: the Rao geodesic distance. Second, the predictions are accompanied by estimates of their accuracy and reliability. The method is applied to the classification of regimes characterized by different types of ELMs based on the measurements of global parameters and their error bars. This yields promising success rates and outperforms state-of-the-art automatic techniques for recognizing ELM signatures. The estimates of goodness of the predictions increase the confidence of classification by ELM experts, while allowing more reliable decisions regarding plasma control and at the same time increasing the robustness of the control system. [ABSTRACT FROM AUTHOR]

In this research, the response of the RC Beam-Column Joint under the cyclic loads was analyzed with a FEM solver (Abaqus) by using various grades of Engineered Cementitious Composite (ECC) in the joint zone. The concrete damage plasticity model for concrete and ECC material under cyclic loading was proposed. Accordingly, the Finite Element Analysis (FEA) model was established with the consideration of different constitutive material models for concrete and Engineered Cementitious Composites. The accuracy of the proposed FEA model was validated with the experimental results. Failure mechanism, crack propagation, moment rotation relationship, and energy absorption under cyclic loading were investigated. Under controlled deformation, cyclic loads were applied to the samples at the end of the beam up to the failure point. It was found that the use of various grades of Engineered Cementitious Composites in the joint zone was effective in enhancing the ultimate moment capacity upto 38.50%, ductility upto 13.72%, and siffniness degradation upto 28.57% respectively of the joint up to the failure stage alongwith significant reduction in crack propagation. [ABSTRACT FROM AUTHOR]

The design of work is a crucial consideration for production workers in terms of performance, satisfaction, and motivation. This aspect has garnered increasing attention in research, particularly with the rise of automation and the transition to Industry 4.0-enabled smart factories. Work design is influenced by both internal and external performance-shaping factors (PSFs). Internal factors include human, machine and task elements and traits, which HR specialists can structure to enhance efficiency and productivity in manufacturing. External PSFs, such as physical, psychological, social and organizational factors, also play a significant role in shaping production work. This study aims to understand the impact of personal characteristics of production workers in an automated factory. The research findings are extrapolated on an Industry 4.0 framework to establish a productive work design. Data collection is conducted through a quantitative survey, and non-parametric analysis of variance tests are employed to assess significant relationships. The results indicate a better perception of the pace of operations (µ = 4.19) and feedback (µ = 4.47) among elder workers. Additionally, educated workers express significant perceptions regarding external PSFs such as supervision (µ = 4.39), health and safety (µ = 4.25), job rotation (µ = 3.91) and pay and welfare (µ = 3.58). Aspiration, motivation and organizational commitment emerge as crucial work design attributes for experienced and married workers. These findings contribute to understanding the structure of modern work design in the context of Industry 4.0, aiming to enhance performance and worker productivity. The study proposes an advanced Industry 4.0 work design framework, empowering HR specialists to develop effective strategies and optimize work distribution. [ABSTRACT FROM AUTHOR]

Internal model principle based repetitive control is widely used in tracking sinusoidal periodic signals of known fixed frequency. The conventional repetitive control (CRC) offers a promising and accurate current control strategy to regulate the sinusoidal input currents at the grid side of shunt active power filters (SAPF) in the presence of fixed reference frequency of the system. However, in practical applications, the frequency of grid varies in limits (though very small) specified by the grid codes. This grid frequency variation causes degradation in the performance of the CRC controller & thus there is a need for a unified repetitive control algorithm to operate satisfactorily under fixed and variable frequency conditions. Lagrange interpolation based fractional order repetitive control provides frequency adaptive capability but it suffers from the online tuning and parameters updating issues. In this work, a Taylor Series expansion based advanced repetitive control (ARC) scheme for shunt active power filters is proposed, to deal with the issue of variable frequency arising in power systems due to a multitude of reasons such as the mismatch between source and load powers. The analysis and synthesis of the ARC system are also presented. The proposed ARC scheme offers optimal performance and thus maintains the grid currents sinusoidal with acceptable and very low total harmonic distortion (THD), in the presence of non-linear loads and variable frequency of the system. The proposed ARC has been applied to a three-phase SAPF. Simulation and experimental results are provided to demonstrate validity of the proposed ARC. [ABSTRACT FROM AUTHOR]

Alkali–silica reaction (ASR) is one of the major durability issues that affect the material degradation and structural performance, compromising the service life of concrete structures. Therefore, this study was planned to investigate the potential of ASR for locally available unexplored and vastly used aggregates, as per ASTM C1260. Aggregates from five different sources (Shalozan, Abbotabad, Orakzai, Swabi and Sada) were procured from their respective crusher sites. Mineralogical components of these aggregates were studied using the petrographic analysis. Cube, prism and mortar bar specimens were cast using mixture design in accordance with ASTM C1260 and placed in sodium hydroxide solution at 80 °C for 90 days. Identical specimens were also cured in water for the purpose of comparison. It was observed that mortar bar expansion of Orakzai aggregate was higher among the other tested aggregates and greater than 0.20% at 28 days, indicating the reactive nature according to ASTM C1260. Petrographic analysis also revealed the presence of reactive silica (quartzite) in the tested Orakzai source. It was observed that the compressive and flexural strengths of specimens exposed to ASR conducive environment was lower than the identical specimens placed in water. For instance, an approximately 9% decrease in compressive strength was observed for Orakzai aggregates exposed to ASR environment at 90 days compared to similar specimens placed in water curing. Moreover, microstructural analysis showed the development of micro-cracks for specimens incorporating Orakzai source aggregates. This study assists the construction stakeholders for the potential of unexplored local aggregates with regard to ASR before its utilization in mega construction projects. [ABSTRACT FROM AUTHOR]

Purpose: Winglets play a major role in saving fuel costs because they reduce the lift-induced drag formed at the wingtips. The purpose of this paper is to obtain the best orientation of the winglet for the Office National d'Etudes et de Recherches Aérospatiales (ONERA) M6 wing at Mach number 0.84 in terms of lift to drag ratio. Design/methodology/approach: A computational fluid dynamics analysis of the wing-winglet configuration based on the ONERA M6 airfoil on drag reduction for different attack angles at Mach 0.84 was performed using analysis of systems Fluent. First, the best values of cant and sweep angles in terms of aerodynamic performance were selected by performing simulations. The analysis included cant angle values of 30°, 40°, 45°, 55°, 60°, 70° and 75°, while for the sweep angles 35°, 45°, 55°, 65° and 75° angles were used. The aerodynamic performance was measured in terms of the obtained lift to drag ratios. Findings: The results showed that slight alternations in the winglet configuration can improve aerodynamic performance for various attack angles. The best lift to drag ratio for the winglet was achieved at a cant angle of 30° and a sweep angle of 65°, which caused a 5.33% increase in the lift to drag ratio. The toe-out angle winglets as compared to the toe-in angles caused the lift to drag ratio to increase because of more attached flow at its surface. The maximum value of the lift to drag ratio was obtained with a toe-out angle (−5°) at an angle of attack 3° which was 2.53% greater than the zero-toed angle winglet. Originality/value: This work is relatively unique because the cant, sweep and toe angles were analyzed altogether and led to a significant reduction in drag as compared to wing without winglet. The wing model was compared with the results provided by National Aeronautics and Space Administration so this validated the simulation for different wing-winglet configurations. [ABSTRACT FROM AUTHOR]

The aim of this work is to evaluate the role of viscosity of the organic condensate obtained from fast pyrolysis of wheat straw. Based on the experimental data, a model has been developed that is able to adequately describe the viscosity as a function of relevant process parameters. The developed model is helpful to investigate the reduction of heat transfer in the heat exchangers of the organic condensate cycle when glycol is replaced by an organic condensate. Temperature, solid contents, and water contents play a significant role and affect the viscosity of bio-oil. As temperature increases, the viscosity of oil reduces rapidly. Viscosity-temperature profile follows an Arrhenius-type-relationship, where the viscosity of the bio-oil decreases exponentially with increasing temperature. As solid content increases, exponential increase of viscosity takes place. However, the increase in water content results in decrease of viscosity on logarithmic scale. The range of water addition in organic condensate is possible up to a certain limit, after certain limit it starts to separate out in two phases. Investigation of reduction of heat transfer in heat exchanger shows that Nusselt number decreases with the increase of viscosity. Therefore, the overall heat transfer coefficient will decrease in case of organic condensate as compared to glycol. [ABSTRACT FROM AUTHOR]

Biodiesel and oxyhydrogen (HHO) gas have shown promising results in improving engine performance and emissions. In this work, the effects of HHO gas and 5% biodiesel blends (B5) and their combined use in a 315 cc diesel engine have been analyzed. Biodiesel is produced by base catalyzed transesterification and cleaned by emulsification. Its calculated cetane index (CCI) was 61.4. HHO gas is produced from electrolysis of concentrated potassium hydroxide solution. The use of 5% biodiesel blend resulted in a significant rise of 9.4% in the brake thermal efficiency (BTE) and a maximum reduction of 8.19% in the brake specific fuel consumption (BSFC). HHO enrichment of diesel and biodiesel at 2.81 L/min through the intake manifold improved the torque and power by an average of over 3%. HHO addition also improved the BTE of diesel by a maximum of 3.67%. The combination of high CCI biodiesel fuel and HHO creates a mixture that has shortened the ignition delay (ID) to the point that adverse effects were observed due to the premature combustion as shown by the average decrease in the BTE of 2.97% compared to B5. Thus, B5, on its own, is found to be the optimum fuel under these conditions. [Display omitted] • Biodiesel purity improved by electrolytic separation and emulsification. • Oxyhydrogen enriched diesel gives significant increase in torque and power output. • Oxyhydrogen enriched biodiesel show adverse effects on engine efficiency. • BSFC and thermal efficiency improved significantly with B5 Blend. [ABSTRACT FROM AUTHOR]

Recent developments in converting the thermal energy of exhaust gasses of automobiles into electric power directly, require an extensive simulation and design of appropriate TEG system. This work aims to create a physical model of engine exhaust system using Simscape language to simulate waste heat recovery from the exhaust gasses using (Na, K) co-doped polycrystalline tin selenide, SnSe, TE material. This particular material exhibits a high Seebeck coefficient and extremely low lattice thermal conductivity in power generation because of phonons scattering by the rattlers (Na, K atoms) and nanostructuring. In the MATLAB/SIMULINK environment, a transient simulation is done for the recovery of waste heat from a 1.5 liters engine using these specific material-based TE modules. According to the results obtained, at the temperature gradient of 285 K across its sides, electrical power of 10.4 W with a conversion efficiency of almost 5% is produced from one module. The total system output power was 477 W at the exhaust gas inlet temperature of 900 K to the octagonal HEx on which the modules are mounted. [ABSTRACT FROM AUTHOR]

Compression ignition engines are one of the world's largest consumers of fossil oil but have energy extraction efficiency limited to 35%. Addition of hydrogen alongside diesel fuel has been found to improve engine performance and efficiency; however, after a certain limit, hydrogen begins to show adverse effects, mainly because the ratio of oxygen to fuel decreases. This can be overcome by using oxyhydrogen, which is a mixture of hydrogen and oxygen gas. In this study, effects of addition of oxyhydrogen generated by electrolysis, with varying flows at the intake manifold, on a 315 cc compression ignition engine alongside diesel were analyzed. The engine was mounted on a Thepra test bed and torque measurements were taken at predetermined test points for diesel and 6 and 10 standard cubic feet per hour flowrates of oxyhydrogen. H10 showed the maximum improvement in engine performance equating to a 22.4% increase in both torque and power at 3000 r/min, and a 19.4% increase in efficiency at 2600 r/min was recorded. The large increase in engine performance as compared to previous results is because of high oxyhydrogen flowrate to displacement volume ratio. The oxyhydrogen flowrate to displacement ratio is the most important factor as it is directly impacts engine performance. The difference in engine performance because of oxyhydrogen becomes prominent at higher engine speed due to high suction pressure. No experimental flowrates of oxyhydrogen showed any adverse effect on the engine performance. [ABSTRACT FROM AUTHOR]

Compression ignition engines are one of the world's largest consumers of fossil oil but have energy extraction efficiency limited to 35%. Addition of hydrogen alongside diesel fuel has been found to improve engine performance and efficiency; however, after a certain limit, hydrogen begins to show adverse effects, mainly because the ratio of oxygen to fuel decreases. This can be overcome by using oxyhydrogen, which is a mixture of hydrogen and oxygen gas. In this study, effects of addition of oxyhydrogen generated by electrolysis, with varying flows at the intake manifold, on a 315 cc compression ignition engine alongside diesel were analyzed. The engine was mounted on a Thepra test bed and torque measurements were taken at predetermined test points for diesel and 6 and 10 standard cubic feet per hour flowrates of oxyhydrogen. H10 showed the maximum improvement in engine performance equating to a 22.4% increase in both torque and power at 3000 r/min, and a 19.4% increase in efficiency at 2600 r/min was recorded. The large increase in engine performance as compared to previous results is because of high oxyhydrogen flowrate to displacement volume ratio. The oxyhydrogen flowrate to displacement ratio is the most important factor as it is directly impacts engine performance. The difference in engine performance because of oxyhydrogen becomes prominent at higher engine speed due to high suction pressure. No experimental flowrates of oxyhydrogen showed any adverse effect on the engine performance. [ABSTRACT FROM AUTHOR]

The electrohydrodynamic deformation of an emulsion droplet with a clean and particle-covered interface was explored. Here, the electrohydrodynamic deformation was numerically and experimentally demonstrated under the stimuli of moderate and strong electric fields. The numerical method involves the coupling of the Navier–Stokes equation with the level set equation of interface tracking and the governing equations of so-called leaky dielectric theory. The simulation model developed for a clean interface droplet was then extended to a capsule model for densely particle-covered droplets. The experiments were conducted using various combinations of immiscible oils and particle suspensions while the electric field strength ~105 V/m was generated using a high voltage supply. The experimental images obtained by the camera were post-processed using an in-house image processing code developed on the plat-form of MATLAB software. The results show that particle-free droplets can undergo prolate (deformation in the applied electric field direction) or oblate deformation (deformation that is perpendicular to the direction of the applied electric field) of the droplet interface, whereas the low-conductivity particles can be manipulated at the emulsion interface to form a 'belt', 'helmet' or 'cup' morphologies. A densely particle-covered droplet may not restore to its initial spherical shape due to 'particle jamming' at the interface, resulting in the formation of unique droplet shapes. Densely particle-covered droplets behave like droplets covered with a thin particle sheet, a capsule. The deformation of such droplets is explored using a simulation model under a range of electric capillary numbers (i.e., the ratio of the electric stresses to the capillary stresses acting at the droplet interface). The results obtained are then compared with the theory and experimental findings. It was shown that the proposed simulation model can serve as a tool to predict the deformation/distortion of both the particle-free and the densely particle-covered droplets within the small deformation limit. We believe that this study could provide new findings for the fabrication of complex-shaped species and colloidosomes. [ABSTRACT FROM AUTHOR]