Pure Power Research Articles

Spatiotemporal analysis of earthquake occurrence in synthetic and worldwide data

The present work presents spatiotemporal analyses of distributions between successive earthquakes. This study comprehends data produced by a modified version of the Olami–Feder–Christensen model with a small-world topology and actual worldwide earthquakes from 2000 to 2019. The distributions were studied from the nonextensive statistical mechanic’s viewpoint, which was shown to be a suitable approach since q-exponential functions produced better fittings to data than pure power laws. Our results show that, by applying scaling relationships, the probability distributions have data collapses in all cases. It reinforces the conception of a critical behavior in the seismological phenomenon and that there is no differentiation between the spatiotemporal statistical features of earthquakes, whether small or large in size or magnitude. In addition, the presence of q-exponential distributions and the ability of a small-world-like OFC model to reproduce spatiotemporal features of real worldwide earthquakes indicate self-organized criticality and long-range spatiotemporal correlations between earthquakes.

High-efficiency photovoltaic-thermoelectric hybrid energy harvesting system based on functionally multiplexed intelligent thermal management

A photovoltaic-thermoelectric hybrid (PV-TEH) system with intelligent thermal management based on the dual functions of thermoelectrics (TEs) is proposed to improve the conversion efficiency of PV cells. The performance of PV cells is highly dependent on the cell temperature, and the temperature gradient can also be used to generate additional electricity. A microcontroller switching circuit is designed using the same thermoelectric module for the functions of thermoelectric generator and thermoelectric cooler (TEG/TEC) to selectively regulate the PV panel temperature according to the heat dissipation requirements. In addition, PWM-based intelligent cooling regulation technology is presented to set up a hybrid energy harvesting and thermal management system with adjustable conversion efficiency. Experimental results show that the conversion efficiency in the proposed hybrid PV-TEH system can reach up to 27.8 % while reducing the temperature of the PV panel by 6℃. Accounting for 23 % of the high-efficiency energy output due to the PV-TEG mode, the time window of the pure power supply is increased to 1.15 h during the 5 h day measurement. In addition, the effective output power of PV is increased from 6 W to 8.1 W in PV-TEC mode. This intelligent energy harvesting and thermal management by employing the TE functionally multiplexed technique can provide a reference for green self-powered electronic equipment.

Do logarithmic terms exist in the drag coefficient of a single sphere at high Reynolds numbers?

At the beginning of the second half of the twentieth century, Proudman and Pearson (J. Fluid. Mech.,2(3), 1956, pp.237–262) suggested that the functional form of the drag coefficient (CD) of a single sphere subjected to uniform fluid flow consists of a series of logarithmic and power terms of the Reynolds number (Re). In this paper, we will explore the validity of the above statement for Reynolds numbers up to 106 by using a symbolic regression machine learning method. The algorithm is trained by available experimental data and data from well-known correlations from the literature for Re ranging from 0.1 to 2×105. Our results show that the functional form of CD contains powers of log(Re), plus the Stokes term. The logarithmic CD expressions can generalize (extrapolate) better beyond the training data than pure power series of Re and are the first in the literature to predict with acceptable accuracythe onset of the rapid decrease (drag crisis) of CD at high Re, but also to follow the right behaviour towards zero Re. We also find a connection between the root of the Re-dependent terms in the CD expression and the first point of laminar separation. The generalization behaviour of power-based drag coefficient equations is worse than logarithmic-based ones, especially towards the zero Re regime in which they give non-physical results. The logarithmic based CD correctly describes the physics from the low Re regime to the onset of the drag crisis. Also, by applying a minor modification in the logarithmic based equations, we can predict the drag coefficient of an oblate spheroid in the high Re regime.

The societal impact of the metaverse

In the 1920s developed a new artistic and cultural movement called “Surrealism”, which not only included the revolutionary paintings and sculptures, but also philosophical texts and novels. Around 100 years later, the arrival of the Metaverse with its independence of physical laws promises to bring Surrealism to a next level. On the other hand, the pure market power of some of the companies developing their concepts may limit this potential freedom for the users. As observed with social media platforms, inside the initial competition, various providers had to close their platforms, leading to today’s oligopoly. This means less choice for the users and a stronger position of the providers to create solutions maximizing their economic benefit. Today, independent companies work on their visions of the Metaverse, but unequal starting positions may make it difficult for them to compete with the established competitors. Similar to the attractivity of social media, also the Metaverse requires a high number of active users and service providers (private companies, but also governmental offices), fostering the tendency to an oligopoly. Based on literature, economy, psychology, and art, this paper discusses the opportunities and risks of the Metaverse, including an outlook on a predicted societal impact, especially laying its focus on the holistic connections of the different points of view. As the Metaverse only appeared in smaller parts yet, academic papers are still lacking. One aim of this article is to start an academic discussion. So far, actual concepts had been widely inspired by popular science fiction novels, ignoring Ray Bradbury’s thoughts: “It’s ‘prevent the future,’ that’s the way I put it. Not predict it, prevent it”.

A two-stage design for comparing binomial treatments with a standard

We propose a two-stage selection and testing procedure for comparing success rates of several populations among each other and against a desired standard success rate to identify which treatment has the highest rate of success that is also higher than the standard. The design combines elements of both hypothesis testing and statistical selection. As a hybrid two-stage procedure, it allows for dropping the poorly performing treatments early on the basis of interim analysis results or for early termination if none of the experimental treatments seems promising. Because this procedure is not a pure hypothesis testing procedure, power and size are redefined to account for its hybrid nature. Using these definitions, we determine the design parameters for given size and power values. When multiple designs meet these requirements, we will recommend the set of design parameters that produces the lowest expected sample size.

Modeling and simulation of pure electric vehicle composite power supply

In order to solve the problem of high discharge current, serious heating and low service life of pure electric vehicle with single power battery system driving at high power. Design a top-level model of the composite power supply with battery and ultra-capacitor for pure electric vehicles in the simulation software ADVISOR, propose an energy management control strategy based on logic threshold control theory. Based on MATLAB/Simulink environment, set up a logic threshold limit filtering power shunt module and chose the working condition of NEDC for simulation. The results show that, compared to single battery system, a composite power system embedded in the logic threshold control strategy of filtering thought can distributes the power between the battery and the ultra-capacitor more reasonably, effectively improves the peak output power of the battery, avoiding high current charge and discharge of batteries, extends the life of the battery, and improve the vehicle's power and economy.

The potential of transcritical cycles based on CO[formula omitted] mixtures: An exergy-based analysis

This paper focuses on the thermodynamic comparison between pure supercritical Carbon Dioxide and blended transcritical Carbon Dioxide power cycles by means of a thorough exergy analysis, considering exergy efficiency, exergy destruction and efficiency losses from Carnot cycle as main figures of merit. A reference power plant based on a steam Rankine cycle and representative of the state-of-the-art (SoA) of Concentrated Solar Power (CSP) plants is selected as base-case. Two different temperatures of the energy (heat) source are considered: 575 °C (SoA) and 725 °C (next generation CSP).Compared to SoA Rankine cycles, CO2 blends enable cycle exergy efficiency gains up to 2.7 percentage points at 575 °C. At 725 °C, they outperform both SoA and pure CO2 cycles with exergy efficiencies up to 75.3%. This performance is brought by a significant reduction in the exergy destruction across the compression and heat rejection process rounding 50%. Additionally, it has been found that the internal condensation occurring inside the heat recuperator for those mixtures with a large temperature glide improves recuperator exergy efficiency, supporting the use of simpler layouts without split-compression. Finally, CO2 blends exhibit lower cycle exergy efficiency degradation than pure sCO2 in the event of an increase in the design ambient temperature.

Model Predictive Phase Control for Single-Phase Electric Springs

In this paper, model predictive control (MPC) is proposed for single-phase electric springs (ESs) with the help of the existing δ control, which is realized by controlling the instantaneous phase angle of the predefined sinusoidal reference of a certain controller. System modeling is analyzed first to get differential forms of state variables. The discrete-time state space model is obtained through first-order approximation. Critical load (CL) voltage can be predicted by the prediction of ES voltage and line current. The operating modes of ESs can be determined and the reference signal for CL voltage can be provided by δ control. As a result, cost function is obtained as the absolute value of the error between predicted CL voltage and its predefined reference. Two typical operating functions such as pure reactive power compensation mode and power factor correction (PFC) mode are selected and simulated to validate the proposed control and analysis. It is revealed that both control objectives can be achieved with the proposed MPC and δ control. Additionally, the total harmonic distortion on the critical load is limited to about 0.5%, which is better than other existing methods.

Slow-roll inflation at N3LO

The next generation of cosmological observations will be sensitive to small deviations from a pure power law in the primordial power spectrum of the curvature perturbations. In the context of slow-roll inflation, these deviations are expected, they correspond to the so-called running of the spectral index. Their measurement would bring as much information as the discovery of deviations from scale invariance. However, robust parameter inference requires to marginalize over any possible higher-order uncertainties which have been, up to now, not fully determined. We tackle this issue by deriving the inflationary scalar and tensor slow-roll power spectra at next-to-next-to-next to leading order, fully expanded around an observable pivot wave number, for all single-field inflationary models having minimal and nonminimal kinetic terms. Our result therefore encompasses string-inspired inflationary models having a varying speed of sound.

Power-flow study for a hybrid AC/DC power system based on the Secant method and the Unified method

High voltage direct current (HVDC) transmission benefits cross-provincial long-distance transmission and nonconcurrent interconnection between frameworks than electric power transmission. Due to the different nature of electric power transmission, the power system analysis has evolved from a pure AC power system to a hybrid AC/DC power system. The high-power electrical energy is transmitted under the premise of the hybrid AC/DC power system. It is necessary to monitor the power flow of the hybrid AC/DC power system to avoid substantial economic losses. Therefore, studying the power flow for such a massive power system is crucial. This paper is proposed to apply the secant method and the unified method to analyze the power flow distribution for the hybrid AC/DC power system. First, the initial value is optimized by using the secant method. Then the optimized value is acted as an initial condition used in the unified method. The results show the combined method’s effectiveness and practicability through the power flow analysis using the IEEE 14-Bus system as the simulation model.

Running coupling and non-perturbative corrections for O(N) free energy and for disk capacitor

We reconsider the complete solution of the linear TBA equation describing the energy density of finite density states in the O(N) nonlinear sigma models by the Wiener-Hopf method. We keep all perturbative and non-perturbative contributions and introduce a running coupling in terms of which all asymptotic series appearing in the problem can be represented as pure power series without logs. We work out the first non-perturbative contribution in the O(3) case and show that (presumably because of the instanton corrections) resurgence theory fails in this example. Using the relation of the O(3) problem to the coaxial disks capacitor problem we work out the leading non-perturbative terms for the latter and show that (at least to this order) resurgence theory, in particular the median resummation prescription, gives the correct answer. We demonstrate this by comparing the Wiener-Hopf results to the high precision numerical solution of the original integral equation.

Deleuze, Bergson, Merleau-Ponty: The Logics and Pragmatics of Creation, Affective Life, and Perception by Dorothea E. Olkowski

Reviewed by: Deleuze, Bergson, Merleau-Ponty: The Logics and Pragmatics of Creation, Affective Life, and Perception by Dorothea E. Olkowski Elodie Boublil OLKOWSKI, Dorothea E. Deleuze, Bergson, Merleau-Ponty: The Logics and Pragmatics of Creation, Affective Life, and Perception. Bloomington: Indiana University Press, 2021. 180 pp. Cloth, $63.00; paper, $28.00 [End Page 152] Dorothea E. Olkowski's latest book carefully examines "the relationship between the creation of ideas and their actualization in relation to semiology, logic and the cosmos in the philosophies of Deleuze, Bergson, and Merleau-Ponty." However, this work is neither an extensive or historical account of Deleuze's, Bergson's, and Merleau-Ponty's philosophies, nor an attempt to homogenize their views on space, time, or perception. Instead, it subtly compares their differences and similarities to move beyond metaphysical dualism, and fruitfully rethinks the relations between formal logic and ontology. Indeed, the author aims to draw a "theory of form," based on the logic of sensation, ultimately designed "to take the place of a theory of the real, of material physical forces." Chapter 1 retraces the history of postmodernist claims and their philosophical legacy. Olkowski explains that postmodernism is not first and foremost a political worldview or a debunking of objectivity in natural sciences. Instead, "it begins as a formal system or series of formal systems." Olkowski explores how Deleuze draws on the knowledge of modern science and logic (Bolzano, Cavaillès) and on Bergson's critical analysis of it to elaborate his logic of sensation. Bergson's conception of affectivity impacted Deleuze's and Merleau-Ponty's theories of corporeality and sensation, and their understanding of perception. Bergson's concept of "body image" specifically influenced Deleuze's elaboration of the concept of "movement-image," through which he tried to overcome the dichotomy set up by mind–body dualism. Chapter 2 focuses on Deleuze and Guattari's critique of logic as an attempt to find a third way between idealism and materialism and to overcome the disconnection between formal logic and lived experience. It reviews their critique of Euclidean geometry, their objections to formal logic as set out by Frege and Russell, and their assessment of phenomenology in order to eventually show Deleuze's affinity with Peirce's pragmatist approach. Then, the author aims to determine if Deleuze's attempt could be compatible with the phenomenology of Merleau-Ponty and Bergson's understanding of quality and multiplicity. Chapter 3 focuses on Bergson. Recalling the controversy with Russell, Einstein, and Langevin, Olkowski refers to Merleau-Ponty's defense of Bergson's concept of intuition to prove the accuracy of his reflection on creative forces and pure duration. As she explains, "[T]he intent here is to clarify the relations between these different aspects of Bergson's thought and draw out how Deleuze makes use of these structures derived from Bergson's philosophy." This leads her to explore, more specifically, how Deleuze reworks the concept of "multiplicity" along the lines of Bergson's analysis of the élan vital. In chapter 4 the author focuses on Deleuze's work on cinema to deepen the philosophical correlation between Bergson's concepts, Deleuze's analysis, and the influences of Merleau-Ponty and Pierce. It aims to rethink the relation between movement and time, notably through the notions of time-image and movement-image. Olkowski notably showcases Deleuze's concept of destiny, "which is the pure power of time that [End Page 153] overflows all possible reaction. It defeats, immobilizes, and petrifies figures in their own affectivity; it sends them to their fate, destroying conventions along the way. For Merleau-Ponty, as for Bergson, acts are still possible in a network of temporal relations so that motion and time are destiny but differently than for Deleuze." Chapter 5 addresses the Phenomenology of Perception and how Merleau-Ponty provides an opportunity to rethink perception. In this book and his Courses on Nature, Merleau-Ponty "does not dismiss either position—that of objective science or that of the natural attitude—but argues that although each contains an element of truth, it is perception and only perception that allows us to bridge the gap between physical reality and behavior/comportment." Deleuze will depart from...

Hartree-Fock type systems: Existence of ground states and asymptotic behavior

In this paper we consider a Hartree-Fock type system made by two Schrödinger equations in presence of a Coulomb interacting term and a cooperative pure power and subcritical nonlinearity, driven by a suitable parameter β≥0. We show the existence of semitrivial and vectorial ground states solutions depending on the parameters involved. The asymptotic behavior with respect to the parameter β of these solutions is also studied.

Spin-Glass-Like Behavior in Mn3Ga0.3Sn0.7N Compound

The magnetic transition, thermal property, and the distance of Mn–Mn of Mn3Ga0.3Sn0.7N compound with the Sn element substitution of Ga in Mn3GaN compounds were investigated. Magnetic measurements indicate that the existence of spin glass system at high temperature (502 K) in Mn3Ga0.3Sn0.7N compound may be attributed to competing antiferromagnetic (AFM) and ferromagnetic (FM) interactions due to the doped Sn inducing ferromagnetic orders in Mn3GaN and the partially random Sn substitute Ga at a corner site of the lattice. It is not clear how much role the pure Sn power, which is not doped into Ga site completely, played in inducing the magnetic characteristic. This finding will be helpful to reveal the mechanism of the antiperovskites’ intriguing physics properties and to develop more smart materials.

Energy-Efficient Electro-Hydraulic Power Source Driven by Variable-Speed Motor

Hydraulic systems are widely used in industry due to their small size-to-power ratios and their ability to produce very large linear force and torque. In traditional hydraulic systems, a variable pump driven by an electric motor is often used as power source. In these systems, the electro-hydraulic power source always operates at its rated speed, causing lots of noise and low energy consumption, especially in no-load and light-load conditions. These problems can be solved by changing the speed of the electric motor according to the load state of the electro-hydraulic power source. In order to improve the energy efficiency of the electro-hydraulic power source and realize pressure and flow control on the basis of low cost, this paper presents the power-source structure of a variable-displacement pressure-compensated pump driven by a variable-speed electric motor; this controls the flow by adjusting the electric motor speed and controls the pressure with the variable-displacement pressure-compensated pump. However, for the variable-speed system, the starting of the electric motor with a load is relatively slow; this makes it difficult to meet the demand of flow control, and will also have a great impact on the power grid. To address these problems, a hydraulic accumulator is introduced to the inlet port of the hydraulic pump to assist in starting the pump. This method can realize the combined control of pressure, flow and power, and has high energy efficiency. This research uses experiments to verify the feasibility of the scheme, and the results show that the starting periods of the power source can be shortened from 2.8 s to 0.7 s when the load pressure is about 18 MPa. Furthermore, regarding maintaining pressure without flow outputs, the energy consumption of the designed power source can be reduced by almost 30% compared with a pure variable-displacement power source.

Effects of Boundary Layer and Local Volumetric Cells Refinements on Compressor Direct Noise Computation

<div class="section abstract"><div class="htmlview paragraph">The use of turbochargers with downsized internal combustion engines improves road vehicles’ energy efficiency but introduces additional sound sources of strong acoustic annoyance on the turbocharger’s compressor side. In the present study, direct noise computations (DNC) are carried out on a passenger vehicle turbocharger compressor. The work focuses on assessing the influence of grid parameters on the acoustic predictions, to further advance the maturity of the acoustic modelling of such machines with complex three-dimensional features. The effect of the boundary layer mesh structure, and of the spatial resolution of the mesh, on the simulated acoustic signatures is investigated on detached eddy simulations (DES). Refinements in the core mesh are applied in areas of major acoustic production, to generate cells with sizes proportional to the local Taylor microscale values. Such an educated guess allows for quality enhancement with a smaller increase in computational costs as compared to more general overall refinements. The reflection-free simulation results are validated against experiments. The experimental data were post-processed with methods from the two-port theory to represent pure acoustic source power density for the acoustic modes, cleaned from test-domain-specific reflections. A detailed comparison between experiments and numerical simulations is carried out. As a result of this study, the most critical parameters for the numerical prediction of turbocharger noise are presented. The results can, furthermore, be used to improve the understanding of grid construction when predicting noise signature for compressor flows.</div></div>

Decision-Making on the Selection of Clean Energy Technology for Green Ships Based on the Rough Set and TOPSIS Method

In the context of the decarbonization of the shipping industry, the application of clean energy technologies is a catalyst for decarbonization. With the number of potential clean energy technologies expanding, the uncertainties in terms of technology maturity, policy regulation, and economics make clean energy technologies decision much more difficult. Therefore, it is urgent to establish a clean energy technology selection scenario for the green ship industry to assist shipowners in decision-making. Based on this, a technology selection model based on rough set (RS) and approximate ideal solution ranking (TOPSIS) is constructed. Using RS to reduce the evaluation index and calculate the weight can avoid the one-sidedness of subjective weighting. Using the TOPSIS method to rank alternatives. This paper selects seven clean energy technology alternatives, namely LNG power, LPG power, methanol power, HVO power, pure battery power, hydrogen fuel cell, and ammonia fuel cell, respectively, as the evaluation objects. Taking two types of vessels as examples, it is concluded that LNG power technology is suitable for large coastal ro-ro passenger vessels, and pure battery power technology is suitable for small inland river short-distances vessels. The results are in line with reality, which verifies the scientificity and validity of the proposed model.

One-Dimensional Modeling and Experimental Analysis of Nail Penetration Thermal Runaway for Large Capacity Li-Ion Power Battery

This paper takes a certain type of large-capacity pure electric vehicle NCM li-ion power battery as the object, and analyzes and studies the process of nail penetration thermal runaway(TR). With the aid of AMEsim one-dimensional simulation software, considering the structure composition of the cell, the heat generation mechanism of each side reaction and the three heat transfer modes of thermal radiation, heat conduction and convective heat transfer between the cells, box and the environment, the thermoelectric characteristics of the battery module (six cells) are modeled. The TR behavior of the battery module during nail penetration is simulated and analyzed, and the experiment of the battery module is carried out according to Chinese new regulation GB 38031−2020. The experimental results verify the accuracy of the established model and the reliability of the simulation results, and provide technical reference for the design and development of battery thermal management such as the prediction of TR temperature and the safety of preventing TRP of battery pack.

On the global behaviors for defocusing semilinear wave equations in ℝ1+2

In this paper, we study the asymptotic decay properties for defocusing semilinear wave equations in $\mathbb{R}^{1+2}$ with pure power nonlinearity. By applying new vector fields to null hyperplane, we derive improved time decay of the potential energy, with a consequence that the solution scatters both in the critical Sobolev space and energy space for all $p>1+\sqrt{8}$. Moreover combined with Br\'{e}zis-Gallouet-Wainger type of logarithmic Sobolev embedding, we show that the solution decays pointwise with sharp rate $t^{-\frac{1}{2}}$ when $p>\frac{11}{3}$ and with rate $t^{ -\frac{p-1}{8}+\epsilon }$ for all $1<p\leq \frac{11}{3}$. This in particular implies that the solution scatters in energy space when $p>2\sqrt{5}-1$.

The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER). III. The Mass Function of Young Stellar Clusters in M33

Abstract We measure the star cluster mass function (CMF) for the Local Group galaxy M33. We use the catalog of stellar clusters selected from the Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region survey. We analyze 711 clusters in M33 with 7.0 &lt; log ( Age / yr ) &lt; 8.5 , and log(M/M ⊙) &gt; 3.0 as determined from color–magnitude diagram fits to individual stars. The M33 CMF is best described by a Schechter function with power-law slope α = − 2.06 − 0.13 + 0.14 , and truncation mass log(M c /M ⊙) = 4.24 − 0.13 + 0.16 . The data show strong evidence for a high-mass truncation, thus strongly favoring a Schechter function fit over a pure power law. M33's truncation mass is consistent with the previously identified linear trend between M c , and star formation rate surface density, ΣSFR. We also explore the effect that individual cluster mass uncertainties have on derived mass function parameters, and find evidence to suggest that large cluster mass uncertainties have the potential to bias the truncation mass of fitted mass functions at the 1σ level.