Energy Conservation Condition Research Articles

Environmentally Benign Room-Temperature Synthesis of Quinoxalines using Silica-Supported PPA as a Recyclable Catalyst

We have reported highly proficient, environmental benign, SiO2@PPA catalyzed protocol for the synthesis of 2, 3-diphenyl quinoxalines via condensation of ophenylene diamine with α-diketones. Surface modified silica with polyphosphuric acid offered outstanding catalytic efficiency at room temperature and it sustained up to fifth cycle. The methodology boasts a hassle-free catalyst preparation process, operates under energy-conserving conditions, yields a commendable (93-84%) output of the targeted moieties and exhibits catalyst recyclability. These appealing features position it as a superior and eco-friendly alternative to traditional methods for synthesizing quinoxalines.

Soliton and dispersive wave generation with third-order dispersion and temporal boundary

We investigate the pulse evolution and energy conservation condition at the temporal boundary under third-order dispersion. When the fundamental soliton crosses the temporal boundary and forms two reflected pulses and one transmitted pulse, the power of the transmitted pulse first increases and then decreases as the incident spectrum shifts toward the blue side. If the transmitted spectrum lies in the anomalous group-velocity dispersion region, second-order soliton is formed and dispersive wave is radiated. We present a modified phase-matching condition to predict the resonance frequencies. The predicted results are in good agreement with the results obtained by numerically solving the nonlinear Schrödinger equation.

Topological slow light enhanced second harmonic generation in double-resonant topological photonic crystal

Generally, the second-harmonic generation and slow light of multi-band topological edge states (TESs) have been studied separately. Therefore, the influence of simultaneous slow light and topology protection on second-harmonic generation (SHG) is deficient. Here, we propose a high-efficiency SHG using dual-frequency TESs in topological photonic crystals (TPCs) with slow-light conditions. The wave vector matching condition and energy conservation condition (frequency doubling) can be achieved by adequately adjusting the overall structural parameters of TPCs. The double-resonant nonlinear interaction between two TESs is enabled using a square lattice TPC. Due to the topological localization of the TES and the long interaction time of slow-light effect, the energy densities of the fundamental wave and SHG are significantly increased. Consequently, the high intrinsic efficiency of SHG can be obtained in the order of 7.40 × 10−4. Our work opens new avenues for using topological protected and slow light enhanced nonlinear frequency conversion in a TPC system.

Thermal Behavior Modeling of Lithium-Ion Batteries: A Comprehensive Review

To enhance our understanding of the thermal characteristics of lithium-ion batteries and gain valuable insights into the thermal impacts of battery thermal management systems (BTMSs), it is crucial to develop precise thermal models for lithium-ion batteries that enable numerical simulations. The primary objective of creating a battery thermal model is to define equations related to heat generation, energy conservation, and boundary conditions. However, a standalone thermal model often lacks the necessary accuracy to effectively anticipate thermal behavior. Consequently, the thermal model is commonly integrated with an electrochemical model or an equivalent circuit model. This article provides a comprehensive review of the thermal behavior and modeling of lithium-ion batteries. It highlights the critical role of temperature in affecting battery performance, safety, and lifespan. The study explores the challenges posed by temperature variations, both too low and too high, and their impact on the battery’s electrical and thermal balance. Various thermal analysis approaches, including experimental measurements and simulation-based modeling, are described to comprehend the thermal characteristics of lithium-ion batteries under different operating conditions. The accurate modeling of batteries involves explaining the electrochemical model and the thermal model as well as methods for coupling electrochemical, electrical, and thermal aspects, along with an equivalent circuit model. Additionally, this review comprehensively outlines the advancements made in understanding the thermal behavior of lithium-ion batteries. In summary, there is a strong desire for a battery model that is efficient, highly accurate, and accompanied by an effective thermal management system. Furthermore, it is crucial to prioritize the enhancement of current thermal models to improve the overall performance and safety of lithium-ion batteries.

Influence of port opening dynamics on the acoustic signature of pneumatic marine seismic sources

Numerical modeling is a powerful tool for predicting the acoustic signature of pneumatic marine seismic sources to maximize low-frequency content and minimize excessively high-frequency content that may harm marine life. Idealized source models often overpredict the peak acoustic pressure, a key quantity in assessing source performance. The dynamics of the shuttle, the mechanical component that controls the early time gas flow rate from the source, contribute to this signal overprediction but often are neglected. We have computed the numerical solution of a quasi-1D model of a large volume source fired underwater. In our model, we couple the shuttle dynamics to the gas dynamics in multiple adjacent chambers in the source. The source is coupled to a spherical bubble through mass and energy conservation conditions. To capture the compressible effect of flow area change in the air exiting the source, we invoke a set of steady-state nozzle flow approximations. We compare model results against data from field tests, where acoustic pressure signals, local pressure within and just outside the source, and temperature inside the source were measured. The maximum value and slope of the initial acoustic pressure peak are overpredicted by the model, but internal pressure and temperature data agree with model predictions. We attribute early time discrepancy between the model and data to unmodeled pressure losses in the gas flow to the bubble and discrepancy over the bubble oscillation timescale to the bubble modeling error. We provide first-order corrections that reduce the model discrepancy in a manner consistent with internal thermodynamic data and quantify the effects of design parameters on the source dynamics.

Spectral Considerations of Entangled Two-Photon Absorption Effects in Hong-Ou-Mandel Interference Experiments.

Recently, different experimental methods intended to detect the entangled two-photon absorption (ETPA) phenomenon in a variety of materials have been reported. The present work explores a different approach in which the ETPA process is studied based on the changes induced in the visibility of a Hong-Ou-Mandel (HOM) interferogram. By using an organic solution of Rhodamine B as a model of nonlinear material interacting with entangled photons at ∼800 nm region produced by spontaneous parametric down-conversion (SPDC) Type-II, the conditions that make possible to detect changes in the visibility of a HOM interferogram upon ETPA are investigated. We support the discussion of our results by presenting a model in which the sample is considered as a spectral filtering function which fulfills the energy conservation conditions required by ETPA, allowing us to explain the experimental observations with good agreement. We believe that this work represents a new perspective to studying the ETPA interaction, by using an ultrasensitive quantum interference technique and a detailed mathematical model of the process.

Data-driven suppression of short-period multiples from laterally varying thin-layered overburden structures

Marchenko multiple elimination methods remove all orders of overburden-generated internal multiples in a data-driven way. In the presence of thin beds, however, these methods have been shown to underperform. This is because the underlying inverse problem requires the information about short-period internal multiple (SPIM) imprint on the inverse transmission to be correctly constrained. This has been addressed in 1.5D media with energy conservation and minimum-phase reconstruction. Extending the applications to two dimensions and, hence, making the step toward field data were believed to be hampered by the need for a multidimensional minimum-phase reconstruction which is (1) not unique and (2) no algorithm has been found to perform this in practice on band-limited data. Here, we address both of these problems with an approach that includes solving the Marchenko equation with a trivial constraint, evaluating the energy conservation condition of its solutions to find the spatially dependent error syndrome, using the 1.5D minimum-phase reconstruction for each shot gather to find the spatially dependent constraint, and finally using that inside another run of the Marchenko equation solver to find a much-improved result. We find that the method works because in 2D media the expression of SPIMs in the inverse transmission coda is approximately 1.5D. We then investigate a class of models and synthetic data sets to verify where the 1.5D approximation starts breaking down. Our analysis indicates that this approach could perform very well in settings with moderate lateral variations, which also is where the (short-period) internal multiples are most difficult to differentiate from primary reflections.

Down-conversion of a single photon as a probe of many-body localization.

Decay of a particle into more particles is a ubiquitous phenomenon to interacting quantum systems, taking place in colliders, nuclear reactors or solids. In a nonlinear medium, even a single photon would decay by down-converting (splitting) into lower-frequency photons with the same total energy1, at a rate given by Fermi's golden rule. However, the energy-conservation condition cannot be matched precisely if the medium is finite and only supports quantized modes. In this case, the fate of the photon becomes the long-standing question of many-body localization, originally formulated as a gedanken experiment for the lifetime of a single Fermi-liquid quasiparticle confined to a quantum dot2. Here we implement such an experiment using a superconducting multimode cavity, the nonlinearity of which was tailored to strongly violate the photon-number conservation. The resulting interaction attempts to convert a single photon excitation into a shower of low-energy photons but fails owing to the many-body localization mechanism, which manifests as a striking spectral fine structure of multiparticle resonances at the standing-wave-mode frequencies of the cavity. Each resonance was identified as a many-body state of radiation composed of photons from a broad frequency range and not obeying Fermi's golden rule theory. Our result introduces a new platform to explore the fundamentals of many-body localization without having to control many atoms or qubits3-9.

Напівемпіричне оцінювання акустичних навантажень на головну частину ракети при нестандартній конфігурації стартових споруд

The paper investigates the possibility of using combinations of two options of wave fields conjugation (the conjugation by points and the root mean square approximation) in the method of partial domains using the example of solving the problem of piston radiation in a finite wedge-shaped waveguide. It is shown that the option of using the root mean square approximation is the best, while the use of the conjugation by points of fields generally simplifies the calculation of the problem. The choice of the required calculation combination depends on the problem under consideration, and it is possible that the combined calculation option may lead to a better solution to the problem in terms of fulfilling the law of energy conservation or field conjugation conditions.

Intervalley scattering induced significant reduction in lattice thermal conductivities for phosphorene.

The thermal transport properties of buckled phosphorene (β-P) and antimonene (β-Sb) are investigated using first-principles methods. The large acoustic-optical phonon gaps of 3.8 THz and 2.2 THz enable the four-phonon interaction to play an important role in phonon scattering for both β-P and β-Sb. Considering the electron-phonon coupling, the lattice thermal conductivity can further undergo 84% decrease to 4.9 W mK-1 for p-type β-P at n = 5 × 1013 cm-2. By quantitatively describing the scattering probability of electrons in different paths combined with electron-phonon coupling matrix element analysis, it is found that multi-valley features of electronic band structure and strong electron-phonon coupling strength make electrons have strong intervalley scattering behavior in β-P. The former plays an important role in the energy conservation condition of the scattering process, and the latter determines the selection rule. Our work elucidates the contribution of higher-order phonon interactions as well as electron-phonon coupling effects to lattice thermal conductivity, and provides a new idea for finding materials with low lattice thermal conductivity induced by intervalley scattering.

Dead Load Allocation in Triple-Cable Suspension Bridges by Adjusting the Unstrained Lengths of Hangers: A Novel Analytical Approach

Triple-cable design of suspension bridges with an ultrawide main girder can improve their mechanical properties, making it lucrative for numerous engineering scenarios. However, its realization requires assigning an appropriate share of the dead load of the main girder supported by three main cables to avoid the middle main cable overload by the main girder’s dead load since the latter would impair the mechanical behavior of the upper transverse beams in the towers and deteriorate the whole bridge’s torsional stiffness. Therefore, this study proposes an analytical approach for dead load allocation to the suspension bridge with three main cables, which adjusts the share of the main girder’s dead load supported by three main cables via changing the unstrained lengths of the hangers. The main advantage of the proposed approach is that it can consider both uniform and nonuniform allocations. The spatial model for the suspension bridge with three cable planes is first converted into a plane model. The relationship between unstrained lengths of the three hangers in the same cross section is determined via the deformation compatibility conditions and one of the following options: (1) equality of stiffness of the two side hangers in the case of a symmetrical plane model; or (2) energy conservation conditions in case of an asymmetrical one. The proposed method was applied to an example of a triple-cable suspension bridge with a main span of 2,100 m and a width of 75 m, and its analytical solutions were compared against finite-element method calculation results. An increase in the share of the main girder’s dead load supported by the two side main cables increased the torsional stiffness of the whole bridge and reduced the vertical load exerted by the middle main cable on the top transverse beam of each tower. Meanwhile, variation of the share of the main girder’s dead load supported by the side and middle main cables only slightly influenced the whole bridge’s vertical and lateral stiffness values. The aforementioned adjustment by the proposed method could be accomplished without increasing the steel consumption of the bridge cables. The results could provide references for the design, static, and dynamic response analysis of similar triple-cable ultrawide suspension bridges.

Recent Advances in Antibacterial Composite Coatings

For the removal of pathogens, classical methods such as chemical disinfection, sterilization (thermal or ionic) are used and continue to be used, but the current conditions of energy conservation and environmental protection require approaching this problem from a different perspective [...]

Energy Aspects of Alfalfa Seed Production in Southern Ukraine

This paper presents the findings of the study on determining the energy efficiency of alfalfa seed production in the first year of life in the south of Ukraine using various technologies, which is relevant for their adequate assessment in conditions of energy conservation of non-renewable resources. The purpose of the study was to determine the most energy-efficient technology for growing alfalfa varieties for seeds. Methods of observation, comparison, and field experiment were used. The study investigated the varieties Nadezhda, Veselka, and Unitro for cultivation using conventional technology (without manual and chemical weeding), which included manual weeding without herbicides and a chemical method to reduce crop contamination. It is established that the production of alfalfa seeds requires a significant expenditure of energy-intensive non-renewable resources for the reliable protection of crops from weeds. It was found that the energy intensity of the technology with chemical weeding of alfalfa crops in the first year of life increased by 32.1-32.4% compared to the control (without weed destruction). Energy consumption reached 13,706 MJ/ha (Nadezhda grade, yield 1.46 centner/ha) against 10374 MJ/ha (yield 0.43 centner/ha) in the control. At the same time, due to the introduction of herbicides, 2.6 times less energy was consumed per 1 centner of seeds (9,388 MJ) compared to the control (24,126 MJ). The energy efficiency coefficient (Kee) for chemical weeding of crops increases from 1.28 to 2.99 (Nadezhda variety) and from 1.35 to 3.13 (Unitro variety). Labour costs are reduced by 2.9 or more times due to chemical weeding of crops. Thus, in the control areas, 25.3 (Nadezhda variety) – 23.3 person-hours were consumed per 1 centner of seeds (Unitro variety), and with the introduction of herbicides, this indicator decreases to 8.8, 8.4 person-hours, respectively. The practical significance of the study lies in the proposal of an energy-saving technology for growing alfalfa for seeds

Influence of the gas-phase Lewis number and thermocapillary stress on motion of a slowly evaporating droplet in Stokes flow

The influence of thermocapillary stresses on motion of a slowly evaporating single-component droplet in Stokes flow is investigated analytically for the situation where the environment does not have a temperature gradient in the far field. The conservation equations are solved in the liquid and gas phases and coupled at the gas–liquid interface by applying conditions for conservation of mass, species, momentum and energy. It is found that thermocapillary stresses may influence droplet motion by changing the the interface velocity, and that the gas-phase Lewis number of the evaporating component determines whether Marangoni effects increase or decrease droplet drag. If the Lewis number is less than unity, then thermal Marangoni effects increase droplet drag, while if the Lewis number is greater than unity, then thermal Marangoni effects decrease droplet drag. This is related to the sign of the temperature gradient along the droplet surface that is induced by convection. It is found that conditions may exist where a vaporizing droplet in a microgravity environment will exhibit continuous translational motion driven by thermocapillary effects.

A semi-analytical solution to the forward–reverse shock hydrodynamics of the gamma-ray burst afterglow

ABSTRACT We extend the standard model of forward–reverse shock (FS–RS) for gamma-ray burst (GRB) afterglow to more general cases. On one hand, we derive the analytical solution to the hydrodynamics of the shocks in two limiting cases, i.e. an ultrarelativistic reverse shock case and a Newtonian reverse shock case. Based on the asymptotic solutions in these two limiting cases, we constitute a semi-analytical solution for the hydrodynamics of the shocks in the generic case, covering the mildly relativistic reverse shock case. On the other hand, we derive the evolution of the system taking into account the condition of energy conservation which is not satisfied in the standard FS–RS model. A generic solution of semi-analytical expressions is also given. In both the extended standard FS–RS model (satisfying pressure balance condition) and the model satisfying energy conservation, we find that the results in the ultrarelativistic reverse shock case and in the early stage of the Newtonian reverse shock case are different from those in the standard FS–RS model by only a factor that close to one while the same initial conditions adopted. However, the asymptotic solutions in the limiting cases are not good approximations to those in the intermediate case. Our semi-analytical results agree well with the numerical results for a large range of model parameters, and hence can be easily employed to diagnose the physical quantities of the GRB shell and circumburst environment.

Structural Decomposition Analysis of Japan\u2019s Energy Transitions and Related CO2 Emissions in 2005\u20132015 Using a Hybrid Input-Output Table

This study investigates Japan’s energy transitions in 2005–2015, which involved massive economic disruptions due to the 2011 Great East Japan earthquake and the Great Recession. A hybrid input-output (IO) table that conforms to the energy conservation condition was newly compiled by integrating the Japanese energy-balance and linked-IO tables. This was employed to conduct a structural decomposition analysis (SDA), which attributes changes in energy consumption and CO2 emissions to the effects of intensity, structure, domestic final demand, and export. These effects were successfully segregated into a profile of energy sources. The results revealed that the structural effect became the dominant driver for decisively reducing energy consumption and emissions of manufacturing and service sectors in the latter period 2011–2015. This suggested that it took time to materialize energy-saving innovations in response to the sudden economic disruptions. Over the entire period, the structural effect was the largest driver contributing to the overall reductions, in part because the other effects tended to cancel out either between energy sources or periods. Therefore, a sensible way to transform Japan to a less energy-intensive, carbon-free society in the future is to improve the non-energy input structures of the manufacturing and service sectors.

Nitrogen Acquisition Strategies Mediated by Insect Symbionts: A Review of Their Mechanisms, Methodologies, and Case Studies.

Simple SummaryNitrogen acquisition strategies mediated by insect symbionts through biological nitrogen fixation (BNF) and nitrogenous waste recycling (NWR) were reviewed and compared in our paper, and a model for nitrogen provisioning in insects was then constructed. In our model, (1) insects acquired nitrogen nutrition from food stuffs directly, and the subprime channels (e.g., BNF or NWR) for nitrogen provisioning were accelerated when the available nitrogen in diets could not fully support the normal growth and development of insects; (2) the NWR strategy was more accessible to more insects due to its energy conservation and mild reaction conditions; (3) ammonia produced by different channels was used for essential nitrogenous metabolites synthesis via the glutamine synthetase and glutamate synthase pathways.Nitrogen is usually a restrictive nutrient that affects the growth and development of insects, especially of those living in low nitrogen nutrient niches. In response to the low nitrogen stress, insects have gradually developed symbiont-based stress response strategies—biological nitrogen fixation and nitrogenous waste recycling—to optimize dietary nitrogen intake. Based on the above two patterns, atmospheric nitrogen or nitrogenous waste (e.g., uric acid, urea) is converted into ammonia, which in turn is incorporated into the organism via the glutamine synthetase and glutamate synthase pathways. This review summarized the reaction mechanisms, conventional research methods and the various applications of biological nitrogen fixation and nitrogenous waste recycling strategies. Further, we compared the bio-reaction characteristics and conditions of two strategies, then proposed a model for nitrogen provisioning based on different strategies.

Optimization of operating conditions for energy conservation in a packed-bed absorber

Indoor humidity can be adjusted by an absorption air conditioning system; however, reaching zero humidity is not absolutely the purpose of such adjustment. Therefore, one of the purposes of this study was to discuss the suitable operating conditions in the packed-bed absorber under conformable environments. Triethylene glycol (TEG) solution was used in this study to remove water vapor from air in a packed-bed absorber. The JMP software was adopted to run the response surface methodology, and the methodology was used to determine the operating conditions in a packed-bed absorber. Both experimental and statistical results demonstrated that the amount of water vapor removed by the packed-bed absorber increased with increases in the gas/liquid flow rates and TEG concentration. Analysis with the response surface methodology suggested that the liquid flow rate should be 0.013 to 0.015 kg/s and that the gas flow rate should be 0.022 to 0.025 kg/s to achieve 65% to 80% flooding. The suggested concentration of TEG solution is 70.65 to 85 wt.% due to the lower absorption performance below 70.65 wt.% and the larger energy consumption beyond 85 wt.%. With this range, not only is the amount of water vapor removed acceptable, but the requirement of energy-saving is met. The average error between experimental and predicted removal amounts is about 3.6%. The statistical method is recommended to obtain the mass transfer correlation for mass transfer devices in various operating conditions and the mass transfer amount can be predicted by the absorber designer.

Interface coupling model of Stefan phase change during thermal dissociation of natural gas hydrate

The thermal dissociation process that occurs in a natural gas hydrate is a Stefan phase-change problem with moving boundaries. Based on the integral form of a heat conduction model, for a continuous single-phase hydrate control volume, the energy conservation condition for interfacial coupling during the Stefan phase-change was built for the control volume of thermal dissociation of a natural gas hydrate with a sharp moving boundary. A Neumann solution of the Stefan phase-change model was obtained for the thermal dissociation in a semi-infinite natural gas hydrate reservoir, using Boltzmann similar variables. A unique solution for the Stefan model was found using a monotonic of the transcendental equation. An example analysis was used to verify, the monotonicity of the transcendental equation, and uniqueness of the solution of the Stefan model. The MATLAB program was used to study, the laws of temperature distribution, and dissociation frontal brim during the thermal dissociation process in a hydrate reservoir. Sensitivity fitting studies showed that, the solution of transcendental equation and interface position gradually increased, whereas, the depth penetrated and time penetrated gradually decreases with increasing temperature.

Crystal symmetry based selection rules for anharmonic phonon-phonon scattering from a group theory formalism

Anharmonic phonon-phonon scattering serves a critical role in heat conduction in solids. Previous studies have identified many selection rules for possible phonon-phonon scattering channels imposed by phonon energy and momentum conservation conditions and crystal symmetry. However, the crystal-symmetry-based selection rules have mostly been \textit{ad hoc} so far in selected materials, and a general formalism that can summarize known selection rules and lead to new ones in any given crystal is still lacking. In this work, we apply a general formalism for symmetry-based scattering selection rules based on the group theory to anharmonic phonon-phonon scatterings, which can reproduce known selection rules and guide the discovery of new selection rules between phonon branches imposed by the crystal symmetry. We apply this formalism to analyze the phonon-phonon scattering selection rules imposed by the in-plane symmetry of graphene, and demonstrate the significant impact of symmetry-breaking strain on the lattice thermal conductivity. Our work quantifies the critical influence of the crystal symmetry on the lattice thermal conductivity in solids and suggests routes to engineer heat conduction by tuning the crystal symmetry.