Ideal Efficiency Research Articles

High-density QTL mapping of leaf-related traits and chlorophyll content in three soybean RIL populations

BackgroundLeaf size and shape, which affect light capture, and chlorophyll content are important factors affecting photosynthetic efficiency. Genetic variation of these components significantly affects yield potential and seed quality. Identification of the genetic basis for these traits and the relationship between them is of great practical significance for achieving ideal plant architecture and high photosynthetic efficiency for improved yield.ResultsHere, we undertook a large-scale linkage mapping study using three mapping populations to determine the genetic interplay between soybean leaf-related traits and chlorophyll content across two environments. Correlation analysis revealed a significant negative correlation between leaf size and shape, while both traits were positively correlated with chlorophyll content. This phenotypic relationship was verified across the three mapping populations as determined by principal component analysis, suggesting that these traits are under the control of complex and interrelated genetic components. The QTLs for leaf-related traits and chlorophyll are partly shared, which further supports the close genetic relationship between the two traits. The largest-effect major loci, q20, was stably identified across all population and environments and harbored the narrow leaflet gene Gm-JAG1 (Ln/ln), which is a key regulator of leaflet shape in soybean.ConclusionOur results uncover several major QTLs (q4–1, q4–2, q11, q13, q18 and q20) and its candidate genes specific or common to leaf-related traits and chlorophyll, and also show a complex epistatic interaction between the two traits. The SNP markers closely linked to these valuable QTLs could be used for molecular design breeding with improved plant architecture, photosynthetic capacity and even yield.

Inverted metamorphic AlGaInAs/GaInAs tandem thermophotovoltaic cell designed for thermal energy grid storage application

We demonstrate an inverted metamorphic multijunction (IMM) photovoltaic cell comprising lattice-mismatched 1.2 eV AlGaInAs and 1.0 eV GaInAs junctions optimized for high-temperature thermophotovoltaic (TPV) applications. This device differs from traditional IMM solar cells because the mismatched junctions are grown at a single lattice constant. This architecture enables removal of the compositionally graded buffer that otherwise filters light from the junctions below and absorbs sub-bandgap light via free-carrier absorption. Sub-bandgap absorption dramatically reduces the efficiency of TPV systems using high reflectivity cells to enable band edge spectrum filtering. Three components required development to enable this device: (1) a lattice-mismatched 1.2 eV AlGaInAs junction, (2) a metamorphic contact layer grown after the graded buffer, and (3) a transparent tunnel junction that sits in front of the 1.0 eV GaInAs junction. Growth conditions that minimize oxygen defect incorporation maximize AlGaInAs cell quality, enabling a 0.41 V bandgap open circuit voltage offset at 22 mA/cm2 under AM1.5D. A mismatched GaInAs:Se layer is developed as a low resistance contact. Lastly, we develop a GaAsSb:C/GaInP:Se tunnel junction suitable for high-power densities with more transparency than the GaAsSb:C/GaInAs:Se structure used in past IMM cells. We characterize the tandem device under a high-intensity spectrum that approximates the emission from a 2150 °C blackbody radiator and deduce a projected ideal TPV efficiency of 39.9% at ∼30% of the blackbody irradiance and 36% ideal TPV efficiency under the full 118 W/cm2 irradiance. Improvements to the back-surface reflectivity and series resistance are expected to increase the ideal TPV efficiency well above 40%.

The Circadian Effect Versus Mesopic Vision Effect in Road Lighting Applications

Several models on the circadian effect have been applied to indoor circadian lighting design, but applications in road lighting have not yet been clarified. Based on existing models and circadian research, we examined equivalent melanopic lux (EML), circadian light (CLA), and circadian stimulus (CS) representing the circadian effect and the S/P ratio representing the mesopic vision effect, among a dataset of light sources at photopic adaptation illuminance values of 1, 3, 10, 30, and 100 lx. The results show that the S/P ratio correlates with EML and CS (or CLA) much stronger than it correlates with color temperature. The EMLs of light sources are below 50 EML in mesopic vision, and the CSs of most light sources are below or around the threshold value of 0.05. We conclude that the circadian effect is not a significant issue in mesopic vision under most conditions and that optimization for mesopic efficiency is still a good strategy. There are quite a few light sources that may achieve both ideal mesopic efficiency and low CS. This work clarifies the circadian effect and mesopic vision effect performance of light sources in mesopic vision and will help guide choosing suitable light sources and optimization strategies for road lighting.

Research on Optimization of Improved Gray Wolf Optimization-Extreme Learning Machine Algorithm in Vehicle Route Planning

With the rapid development of intelligent transportation, intelligent algorithms and path planning have become effective methods to relieve traffic pressure. Intelligent algorithm can realize the priority selection mode in realizing traffic optimization efficiency. However, there is local optimization in intelligence and it is difficult to realize global optimization. In this paper, the antilearning model is used to solve the problem that the gray wolf algorithm falls into local optimization. The positions of different wolves are updated. When falling into local optimization, the current position is optimized to realize global optimization. Extreme Learning Machine (ELM) algorithm model is introduced to accelerate Improved Gray Wolf Optimization (IGWO) optimization and improve convergence speed. Finally, the experiment proves that IGWO-ELM algorithm is compared in path planning, and the algorithm has an ideal effect and high efficiency.

Theoretical maximum efficiency and higher power output in triboelectric nanogenerators

The maximum output work and the corresponding output efficiency in energy conversion devices are key criterions, which can provide the direction of performance optimization and the range of performance improvement. In this paper, one cycle model for maximum output work is established to investigate the maximum output efficiency, and another cycle model for combined load is proposed to obtain higher output power for triboelectric nanogenerators (TENGs). By calculating the minimum input work and the maximum output work, the maximum output efficiencies of four basic modes in TENGs are derived. With the assumption of ideal parallel-plate capacitor in TENG, the maximum output efficiencies of both contact-separation (CS) mode and lateral sliding mode (LS mode), which is only determined by the maximum separation distance and shape parameter of dielectric layer (equivalent thickness or length), are similar to Carnot efficiency in heat engines. A relationship between output efficiency and output power is analyzed, which shows that the output power presents a parabolic-like curve with varying output efficiency. There is an ideal output efficiency point, at which the output power obtains the maximum. To improve the output performance, the averaged output powers of the cycles for different single loads and combined loads are calculated and compared in four basic modes of TENGs. In the combined load model, large resistance can effectively enhance the voltage during moving forward and moving backward processes, and small resistance can improve the amount of transferred charge during static process. The result shows that the averaged output power of the combined load is higher than the averaged power at both a single load and optimal matching load. Therefore, the combined load effectively improves the energy utilization of TENGs.

The Effects of EGR Composition on Combustion Performance and Efficiency

<div class="section abstract"><div class="htmlview paragraph">Because of the thermodynamic relationship of pressure, temperature and volume for processes which occur in an internal-combustion engine (ICE), and their relationship to ideal efficiency and efficiency-limiting phenomena e.g. knock in spark-ignition engines, changing the thermo-chemical properties of the in-cylinder charge should be considered as an increment in the development of the ICE engine for future efficiency improvements. Exhaust gas recirculation (EGR) in spark-ignited gasoline engines is one increment that has been made to alter the in-cylinder charge. EGR gives proven thermal efficiency benefits for SI engines which improve vehicle fuel economy, as demonstrated through literature and production applications. The thermal efficiency benefit of EGR is due to lower in-cylinder temperatures, reduced heat transfer and reduced pumping losses. The next major increment could be modifying the constituents of the EGR stream, potentially through the means of a membrane. By doing so, this can change both the chemical and thermodynamic properties of the in-cylinder gas mixture and therefore have an impact on combustion and efficiency. This study evaluated conventional EGR, CO<sub>2</sub>-only and N<sub>2</sub>-only EGR on a single-cylinder engine under non-knocking and knock limited conditions. Overall, this study demonstrated the impacts of CO<sub>2</sub>-only and CO<sub>2</sub>-reduced EGR on efficiency, combustion stability, burn rate, knock abatement and compression ratio on a single-cylinder engine. Through analysis with Chemkin and GT-Power, it also sought to explain the behaviors observed.</div></div>

Improved silicon oxide/polysilicon passivated contacts for high efficiency solar cells via optimized tunnel layer annealing

It is well known that the quality of contact passivation can greatly influence the efficiency of Si solar cells. In this work, the impact of annealing a wet-chemically formed silicon oxide (SiOx) tunnel layer (prior to poly-Si capping) to form SiOx/n+ poly-Si passivated contacts for high efficiency solar cells is investigated. The effect of different annealing temperatures (ranging from 425 to 900 °C) and ambients (air and forming gas), on the overall performance of the resulting SiOx/n+ poly-Si passivated contacts are studied. The efficiency potential of these SiOx/n+ poly-Si contacts is calculated from the measured values of the recombination current density (J0,contact), and the effective contact resistivity (ρcontact), according to the generalized Brendel's model. The results are compared to the reference case, i.e. non-annealed SiOx tunnel layer with poly-Si deposition. The lifetime, the fixed charge and also the SiOx tunnel layer thickness increase upon annealing at higher temperatures. The sample annealed in forming gas at 900 °C shows an increase in field effect passivation (Qtot = 1 × 1012 cm−2) as well as in chemical passivation (Dit = 3 × 1011 eV−1 cm−2), along with reduced ρcontact, indicating pinhole formation upon annealing at 900 °C. The best SiOx/n+ poly-Si passivated contact achieved J0,contact = 4.2 fA cm−2, ρcontact = 0.27 Ω cm−2 and a corresponding maximum ideal efficiency potential of 27.9%. This is 1.2% absolute higher as compared to the reference case, when no annealing of the tunnel layer is performed.

Airy Beam Generation: Approaching Ideal Efficiency and Ultra Wideband with Reflective and Transmissive Metasurfaces

AbstractAiry beams are essential for photonic applications, owing to their intriguing diffraction‐free, self‐accelerating, and self‐healing properties. Recently, 2D metasurfaces have offered great opportunities for generating Airy beams within subwavelength thickness. However, they suffer from the bottlenecks of low efficiency and narrow bandwidth, which may limit their applications in practice. In this study, a strategy is proposed to design amplitude‐ and phase‐controllable metasurfaces that can generate desirable high‐efficiency and ultra wideband Airy beams, based on the Jones matrix analysis. Two exemplary prototypes of Airy beam generators operating in reflection and transmission geometries are demonstrated in the microwave region, achieving high efficiency approaching the theoretical limitation in an ultrawide bandwidth (fractal bandwidth of 84% for reflective prototype and 118% for transmissive). The results show a significant advantage of the bandwidth and total efficiency over low‐thickness metasurfaces. The proposed strategy and metasurface generators may trigger great interest in ultra wideband and high‐efficiency wave manipulations, with small thickness and flat profile compatible with integrated systems, which hold promise for structured light, metaoptics, beam shaping, and advanced holography.

Diffuser design and experimental research of a large-scale chilled water storage system

ABSTRACT Naturally stratified technology is the most economical and effective method in chilled water storage technique and its core is the design of water diffuser. The better the performance of diffuser and the higher the efficiency of chilled water storage is. With the development of science and technology, many large-scale scientific facilities come into being, most of which need to be equipped with large-scale water storage system and run in the extreme operating conditions. If these water storage systems adopt the naturally stratified technology, it is necessary to optimize the design of the diffuser to achieve an ideal storage efficiency, which can not only save energy but also guarantee the operation of the facilities. The water storage system of Steady High Magnetic Field Facilities is one of the representative water storage systems with large flow rate and large temperature difference. By establishing the discrete equation of heat conduction, the results show that the convection doping related to the design of the diffuser is the primary factor affecting the thickness of thermocline. It was also verified by experiments that the large-scale chilled water storage device with well-designed octagonal diffuser and uniform flow orifice can achieve ideal storage efficiency under the operation conditions of large flow rate and large temperature difference.

Experimental and kinetics investigations of separated-gasification chemical looping combustion of char with an iron ore as the oxygen carrier

This study presents the results obtained from a lab-scale two-stage reactor system to investigate the reaction characteristics and chemical kinetics of separated-gasification chemical looping combustion (SG-CLC) with a coal char as the fuel. The results have shown that there is huge mismatch of reaction rate between the slow gasification of char occurred in the gasification reactor (GR) and the rapid redox reactions of oxygen carrier (OC) and gasification products occurred in the reduction reactor (RR). Hence, the GR is recommended to be operated over 950 °C for a carbon conversion higher than 90% at the reaction time of 15 min, while 900 °C should be enough for the RR with an ideal gas combustion efficiency (>99%). Besides, the OC in SG-CLC shows favorable cycle stability, which can be attributed to the indirect mixing between the OC and char so that the attachment of potassium salt from the ash to the OC surface can be effectively avoided. In addition, the reaction kinetics models are determined to obtain the kinetics parameters of the char-fueled SG-CLC. The apparent activation energy is found to be 154.44, 149.79 and 161.42 kJ/mol for the first-order Kinetics Model, 2-D Contraction Model, and 3-D Contraction Model, respectively.

Recovery of iodide as triiodide from thin-film transistor liquid crystal display wastewater by forward osmosis

Triiodide, a larger charged molecule compared to iodide, is thermodynamically favored with the presence of both iodide and iodine, and is easier to be retained by membrane processes. For the first time, iodide was recovered in the form of triiodide by forward osmosis (FO) for thin-film transistor liquid crystal display industries by preoxidation of iodide to triiodide. Partial oxidation by NaOCl was used to convert the iodide to iodine and then to form triiodide. Ethylenediaminetetraacetic acid disodium salt (EDTA-2Na), a commonly used chelating agent in the industry, was used as the draw solute because of its low reverse salt flux. The results revealed that the ideal efficiency of iodide recovery was at pH 3 with a preoxidation (adding 0.0150 M NaClO) for the 0.048 M iodide wastewater with a recovery of 98.5%. Additionally, the Pourbaix diagram and starch indicator were used to verify the formation of triiodide. Membrane distillation was demonstrated to recover the EDTA-2Na draw solute, and more than 99% of recoveries for the draw solutes with initial water flux of 12.0 L/m2 h were achieved, indicating that simultaneous recovery of the EDTA-2Na draw solute and water is feasible.

Intrinsic photopeak efficiency measurement and simulation for pixelated CdZnTe detector

Intrinsic photopeak efficiency of pixelated CdZnTe detectors is an important property for quantitative measurements and analysis, especially for detection and characterization of special nuclear material (SNM). The intrinsic photopeak efficiency of a single 20 mm × 20 mm × 15 mm CdZnTe detector from 59 keV to 2614 keV are measured in experiment. However, compared to the simulated ideal intrinsic photopeak efficiency, the measured efficiency showed deficit. A detailed simulation model including gamma-ray interaction physics, readout electronic as well as signal reconstruction process is built to explain this observed efficiency deficit. The simulated efficiencies of the new model match with experimental results well after taking these factors into account. Efficiency loss due to the guard ring and anode side inaccurate reconstruction are the most important factors. Other miscellaneous efficiency loss mechanisms are discussed too.

Waste heat to power conversion by means of thermomagnetic hydrodynamic energy harvester

Energy harvesting from extremely low enthalpy sources can play an important role in increasing the sustainability of future energy applications: low temperature differences are common and offer an abundant source, available both in the natural environment and as the result of a many industrial process. This paper presents the first closed-loop thermomagnetic hydrodynamic energy harvester, based on thermomagnetic advection and exploiting a commercial ferrofluid. The lab-scale prototype has a toroidal geometry adopted from the well-known tokamak inertial machines. Peltier modules are used to control the thermal gradient that is harvested and converted directly to electric energy, while permanent magnets trigger the advection. Temperature sensors are installed along the toroidal walls (thermistors) and are placed in contact with the rotating fluid (thermocouples). To extract and ensure the electrical energy output, the structure is wrapped-up with induction coils. Two coil configurations (purely poloidal and mixed poloidal/toroidal windings) are tested, in a heterogeneous two-phase flow from the combination of water carrier and ferrofluid packets, reaching a maximum extracted electrical power per unit of temperature difference of 10.4 μW/K. This positions the device close to 20% of the ideal Carnot efficiency of a thermal machine working on the same temperature drop. Numerical analysis of the system has been performed developing a Fortran™ code in a Eulerian framework, using a mixed Fourier-Galerkin/finite difference spatial discretization. The harvester is suitable for producing electricity from running engines, appliances, warm gas exhausts, exothermic processes.

Theoretical exploration of quantum efficiency ofAlxGa1 −xNmonolayer photocathode with varying Al contents and ultra‐thin emission layer

To obtain high-efficiency AlGaN monolayer photocathode, the quantum efficiency formulas of reflection-mode and transmission-mode AlxGa1 − xN monolayer photocathode with varying Al contents and ultra-thin emission layer are derived in this article. Based on the formulas, we have simulated quantum efficiency of AlxGa1 − xN monolayer photocathode under different conditions. The results reveal that built-in electric field caused by varying Al contents can significantly promote quantum efficiency of photocathode. If difference in Al contents between adjacent AlxGa1 − xN monolayer enlarges, quantum efficiency will decrease. At the same time, built-in electric field also plays a great impact in stabilizing quantum efficiency and photoelectric emission performance of AlxGa1 − xN monolayer photocathode. The ideal quantum efficiency and photoelectric emission performance can be obtained when buffer layer thickness is about 50 to 75 nm. In addition, when emission layer is composed of a larger number of AlxGa1 − xN monolayers with varying Al contents, the more number of monolayers with high Al contents are, the higher the quantum efficiency is. This study can give useful help for design and preparation of AlxGa1 − xN monolayer photocathodes with varying Al contents.

THE USE OF ECO-FRIENDLY WILD ONION EXTRACT (URGINEA MARITIMA) AS CORROSION INHIBITOR FOR CARBON STEEL IN HYDROCHLORIC ACID

Even though various synthetic compounds have a well action as anticorrosive, they are not cheap and are toxic to both environment and humans. Nevertheless, in C-steel, there is a vital concern, which is serious corrosion issues happen through exposure to environments of aggressive acidity i.e., descaling, oil well solutions of acidity, and pickling. Hence, this study aimed to evaluate the inhibition effect of wild onion (WO) extract as an eco-friendly inhibitor on the behavior of corrosion for C-steel in 0.5 M HCl through the conventional weight loss approach. Various concentrations (0%, 0.5%, 1%, 1.5%, 2%, and 2.5%) of inhibitor in various times of immersion (2, 4, and 8 h) and at different temperatures (25°C, 35°C and 45°C) were investigated for their C-steel corrosion inhibition in corrosive media. In the presence and absence of the inhibitor, the corrosion rate (CR) was investigated as affected by temperature. The concentration of the inhibitor and temperature-controlled the inhibition efficiency %E of the inhibitor. At the existence of wild onion extract, the ideal efficiency of inhibition for C-steel was 98.95%, 88.99%, and 86.79% at 2.5% inhibitor concentrations at the preceding temperatures, respectively. It was noticed that adsorption was spontaneous and physical as proved through adsorption value of free energy ΔG°ads (‒13.5 kJ/mol) and also fitted Langmuir adsorption isotherm. The surface coverage θ and corrosion current density Icorr data confirmed the previous result where inhibition is due to the adsorption of physical nature for the components of the additive on the C-steel surface.

Quantum Carnot cycle with inner friction

A single driven spin is investigated as the working substance of a six-stroke irreversible quantum Carnot cycle. The role of inner friction associated with the finite-time adiabatic transformations on the cycle efficiency and the harvested work are investigated in detail. The inner friction is found to significantly reduce the work output and the cycle efficiency which can make the engine incapable to produce positive work for the too fast adiabatic transformations. The ideal Carnot efficiency is found to be reached only for the quasistatic transformations. A deviation of the cycle efficiency from the classical Carnot efficiency has been given by an efficiency lag which is directly related to the total entropy production due to the inner friction. The released heat in the relaxation processes of the cycle is associated with the entropy production and the inner friction. The extension of the results for a scale-invariant quantum working substance and the possible experimental implementation of the irreversible quantum Carnot cycle in a liquid-state nuclear magnetic resonance setup are also discussed.

Liquid-state pyroelectric energy harvesting

Abstract

Immobilizing perovskite CsPbBr3 nanocrystals on Black phosphorus nanosheets for boosting charge separation and photocatalytic CO2 reduction

Direct conversion CO2 to useful chemical fuels by photocatalysis has been considered to be a promising strategy for renewable energy production. The realization of this goal relies mainly on the development of photocatalysts with ideal charge separation efficiency. Here, we use all-inorganic perovskite nanocrystals (CsPbBr3) immobilized on two-dimensional (2D) black phosphorus nanosheets (BP), resulting in a new and effective CsPbBr3/BP photocatalyst for CO2 photoreduction. Compare to pristine CsPbBr3, the introduction of BP generates more active sites for facilitating CO2 activation and trapped the excited electrons from CsPbBr3 with high charge separation efficiency. Time-resolved photoluminescence and transient absorption measurements together with density functional theory calculations provide a clear elucidation of the charge separation pathways that contribute to the enhanced CO2 conversion rate. This significant feature provides a new venue for constructing all-inorganic perovskite-based photocatalyst by combining with BP for solar energy conversion and artificial photosynthesis.

Experimental Investigation of Performance Enhancement of a Vapor Compression Refrigeration System by Vortex Tube Cooling

This study aimed to analyze the difference in operation of the vapor compression refrigeration (VCR) system with vortex tube cooling. By using varied loads, experiments were conducted on the evaporator section of a vapor compression refrigeration system. In an attempt to improve the use of subcooling for the refrigeration, the effect of subcooling of refrigerant by vortex tube cooling was likewise examined. The test conditions included various loads (25%, 50%, 75% and 100%) and cold mass fractions (25%, 50% and 75%). This research described coefficient of performance (COP) as one of the significant parameters, in addition to heat rejection and refrigerating effect. The ideal efficiency appeared to be with the cold mass fraction of 25% and load of 100%, as identified by the results. Consequently, the COP could be enhanced by 5.16% along with an approximately 4.36% decline in average power use. Improved guidelines for vapor compression refrigeration systems to enhance the operation of the system are an expected benefit of this study.

Exactly solvable two-terminal heat engine with asymmetric Onsager coefficients: Origin of the power-efficiency bound.

An engine producing a finite power at the ideal (Carnot) efficiency is a dream engine which is not prohibited by the thermodynamic second law. Some years ago, a two-terminal heat engine with asymmetric Onsager coefficients in the linear response regime was suggested by Benenti etal. [Phys. Rev. Lett. 106, 230602 (2011)10.1103/PhysRevLett.106.230602], as a prototypical system to make such a dream come true with nondivergent system parameter values. However, such a system has never been realized, in spite of many trials. Here, we introduce an exactly solvable two-terminal Brownian heat engine with the asymmetric Onsager coefficients in the presence of a Lorenz (magnetic) force. Nevertheless, we show that the dream engine regime cannot be accessible, even with the asymmetric Onsager coefficients, due to an instability keeping the engine from reaching its steady state. This is consistent with recent tradeoff relations between the engine power and efficiency, where the (cyclic) steady-state condition is implicitly presumed. We conclude that the inaccessibility to the dream engine originates from the steady-state constraint on the engine.