Initial Power Research Articles

Scaling Inclusive Teaching: A National STEM Teaching Initiative Centering Identity, Power, and Privilege

Scaling Inclusive Teaching: A National STEM Teaching Initiative Centering Identity, Power, and Privilege

The case for agency: Three dimensions of discretion in presidential agenda construction

AbstractWhen scholars address presidential agenda setting, they focus on how presidents go about getting what they want. We know far less about the prior step: how presidents decide what they want (agenda construction). Moreover, prior work that has dealt with this topic has focused on the external constraints imposed on presidential choice by Congress and public opinion. I contend, by contrast, that presidents have considerable agency in determining their domestic policy priorities. They rely on it to establish who they are and where they want to take the nation, putting forward their own “political projects.” I situate this agency in the selection of agenda items and the manner and sequence in which presidents pursue them. Failing to account for this “power of initiative and origination” leaves us with an underspecified understanding of presidential decision making that obscures the consequentiality of leadership in driving important policy outcomes. I develop this argument by exploring three presidential administrations that pose a hard test for my agency thesis: Richard Nixon, George H. W. Bush, and George W. Bush. These case studies draw from archival records obtained at the associated presidential libraries and interviews with senior administration personnel.

THE TRANSHISTORICAL MEANINGS OF UKRAINIAN TRADITION IN THE GUIDELINES OF MODERN NATIONAL PATRIOTIC EDUCATION

The article is devoted to the analysis of the historical foundations and theoretical foundations of the formation of effective foundations of modern national-patriotic education in the contexts of war and peace. Particular attention is paid to revealing the internal dialectic and tragedy of the self-assertion of the Ukrainian idea during the times of enslavement and colonization. The article proves that even when the Ukrainian intelligentsia, trying to balance between East and West, could not decide on national priorities, dividing Ukraine between Muscovites and the Polish nobility, the leading role of preserving and transmitting national meanings was assigned to folk art, which even through the ages has preserved its creative potential and the power of initiative. It has been proven that heroic epics contain experiences of cultural and social traumas, as well as deep philosophical reflections on the strength of the national character, the ability to sacrifice for the sake of the Motherland. The author hopes that this will allow not only to find out the actual significance of the historical-cultural component in the strategies of national-patriotic education, but also to carry out a methodological procedure for distinguishing effective and appellate patriotism on a practical level, which will allow developing a comprehensive program of actualizing the transhistorical meanings of national-patriotic education and military-patriotic education in modern educational practices. Undoubtedly, the use of the heuristic potential of the national tradition as a guide for the development of the theoretical and methodological foundations of patriotic education requires a critical reflection of the experience of their theoretical understanding in the problematic field of the philosophy of education and philosophical anthropology. This will make it possible to identify pathologies and minimize the risks of resuscitation of totalitarian practices in the education of patriots. The identified features and specifics of the implementation of national-patriotic education in wartime will allow the transition from the policy of duty to the policy of responsibility. It is noted that an important role is played by the actualization of the semantics of heroization, militarization and the formation of a positive topos of a serviceman.

Enhancing the indoor performance of organic photovoltaic devices: interface engineering with an aminobenzoic-acid-based self-assembled monolayer

Significant advances in the performance of organic photovoltaic (OPV) devices can facilitate their use in internet of things applications. However, achieving excellent photostability and high efficiency using stable, efficient OPV devices in indoor settings is considerably difficult. To address this issue, a zinc oxide (ZnO) electron transport layer (ETL) was modified with a self-assembled monolayer of 4-aminobenzoic acid (ABA) in the present study, and the impact of this modification was correlated with the indoor performance of an OPV device with the PM6:L8-BO photoactive layer. The ABA-treated ZnO ETL exhibited a significant reduction in the work function (from 4.51 to 4.04 eV), surface roughness (from 0.201 to 0.177 nm), and hydrophilicity of an indium-tin-oxide electrode; this aided in selectively extracting charge carriers from the device and minimizing trap-assisted recombination losses. Additionally, the ABA treatment of the ZnO ETL considerably enhanced the electron mobility and recombination resistance. It reduced the trap density, thereby enabling the ZnO/ABA-based device to achieve improved performance. Consequently, the ZnO/ABA-based device exhibited a noteworthy 14.68% higher maximum power output than that of the device without any ZnO surface modification under 1000 lx halogen (HLG) illumination (P out, max = 354.48 and 309 µA cm−2, respectively). Moreover, under thermal illumination conditions (1000 lx HLG lighting), the ZnO/ABA-based device sustained ∼74% of its initial power conversion efficiency over 120 h, significantly higher than its ABA-free equivalent (∼55%).

Tailoring the Buried Interface by Dipolar Halogen-Substituted Arylamine for Efficient and Stable Perovskite Solar Cells.

Improving the quality of the buried interface is decisive for achieving stable and high-efficiency perovskite solar cells. Herein, we report the interface engineering by using dipolar 2,4-difluoro-3,5-dichloroaniline (DDE) as the adhesive between titanium dioxide (TiO2) and MAPbI3. By manipulation of the anchoring groups of DDE, this molecule not only passivated defects of TiO2 but also optimized the energy level alignment. Furthermore, the perovskite film on the modified TiO2 surface showed improved crystallinity, released residual stress, and reduced trap states. Therefore, these benefits directly contribute to achieving a power conversion efficiency of up to 22.10%. The unencapsulated device retained 90% of initial power conversion efficiencies (PCE) after continuous light illumination for 1000 h and 93% of initial PCE after exposure to air with a relative humidity of 30-40% for over 3000 h. Moreover, the performance of PSCs based on FA0.15MA0.85PbI3 has also increased from 20.48 to 23.51%. Our results demonstrate the effectiveness and universality of dipolar halogen-substituted arylamine (DDE) for enhancing PSC performance.

The Propagation Dynamics of the Symmetric Pearcey Gaussian Beam in the Kerr Medium

AbstractIn this paper, symmetric Pearcey Gaussian beams (SPGBs) are studied in a Kerr medium. By varying the initial input power, the autofocusing ability of the beams is investigated, to find a clear restrictive relationship between the breath‐like structure and the initial input power. The critical collapse power is investigated when SPGBs change from discrete beams to regular breath‐like structure. Finally, the transmission of SPGBs is discussed under different phase modulation when SPGBs are affected by astigmatic, the whole beam is rotated and the angle of rotation can be controlled.

Boron-alloyed porous network platinum nanospheres for efficient oxygen reduction in proton exchange membrane fuel cells

Alloying (or doping) non-metals with platinum (Pt) is an advanced solution for the development of high-performance Pt-based electrocatalysts for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). Herein, we report boron (B)-alloyed Pt nanospheres (B-PtNSs) with a porous network nanostructure by a combination strategy of confinement reduction and post-boronation. B-alloying can induce effective electronic/geometric structures, strong Pt-B coordination, and lowered d-band center to weaken the binding energy of oxygenated intermediates on the Pt surface. The H2-O2 PEMFC with such a B-PtNSs/C as the cathode catalyst can reach a maximum power density of 1.49 W cm−2, about 1.28 times higher than that of Pt/C. After 30,000 voltage cycles in the range of 0.6 ∼ 0.95 V, only a 14.1 % loss of initial peak power density can be observed, while that with Pt/C declines 45.7 %. Non-metals alloying with Pt-based nanostructures can enable high-performance ORR electrocatalysts for their practical application in PEMFCs.

Developing high-power Li||S batteries via transition metal/carbon nanocomposite electrocatalyst engineering.

The activity of electrocatalysts for the sulfur reduction reaction (SRR) can be represented using volcano plots, which describe specific thermodynamic trends. However, a kinetic trend that describes the SRR at high current rates is not yet available, limiting our understanding of kinetics variations and hindering the development of high-power Li||S batteries. Here, using Le Chatelier's principle as a guideline, we establish an SRR kinetic trend that correlates polysulfide concentrations with kinetic currents. Synchrotron X-ray adsorption spectroscopy measurements and molecular orbital computations reveal the role of orbital occupancy in transition metal-based catalysts in determining polysulfide concentrations and thus SRR kinetic predictions. Using the kinetic trend, we design a nanocomposite electrocatalyst that comprises a carbon material and CoZn clusters. When the electrocatalyst is used in a sulfur-based positive electrode (5 mg cm-2 of S loading), the corresponding Li||S coin cell (with an electrolyte:S mass ratio of 4.8) can be cycled for 1,000 cycles at 8 C (that is, 13.4 A gS-1, based on the mass of sulfur) and 25 °C. This cell demonstrates a discharge capacity retention of about 75% (final discharge capacity of 500 mAh gS-1) corresponding to an initial specific power of 26,120 W kgS-1 and specific energy of 1,306 Wh kgS-1.

Subsidy, tax or green awareness: Government policy selection for promoting initial shore power usage and sustaining long-run use

Shore power (SP) can provide electricity from the land for ships instead of from ship engines; this approach can eradicate carbon emissions and foster green port development. However, due to the high SP installation cost and high electricity prices faced by shipping operators, the utilization rate of SP is still low. For the government, it is important and urgent to develop an effective policy to promote shore power usage. However, previous studies have not compared the effects of different government policies and have ignored the differences in SP usage stages. Therefore, in this study, three kinds of policies, subsidy, carbon tax and shipper green awareness improvement, are taken into consideration. The SP usage process is divided into two stages, namely, stimulating ship retrofitting for SP in the short term and sustaining SP usage in the long run. The purpose of this study is to provide policy-selection suggestions for short- and long-term SP promotion. Considering shipping supply chain competition, game theory is applied, and a series of Nash game models are formulated to investigate the equilibrium strategies of shipping operators on SP usage under different policies. A comparison of the results reveals that in the short run, the subsidy policy is superior to the carbon tax policy when both can promote SP usage. However, a moderate carbon tax is able to remedy the failure of subsidies. In the long run, a carbon tax may promote SP at the cost of diminishing social welfare. Improving shipper green awareness is more likely to be a preferable choice for both SP usage and social welfare. This paper also analyses the impacts of scale-based port congestion and green awareness. These findings can provide valuable suggestions for government and shipping operators to promote SP usage, reduce emissions and achieve the goal of green port construction.

Hybrid model for wind power estimation based on BIGRU network and error discrimination‐correction

AbstractAccurate estimation of wind power is essential for predicting and maintaining the power balance in the power system. This paper proposes a novel approach to enhance the accuracy of wind power estimation through a hybrid model integrating neural networks and error discrimination‐correction techniques. In order to improve the accuracy of estimation, a bidirectional gating recurrent unit is developed, forming an initial wind power estimation curve through training. Additionally, a sequential model‐based algorithmic configuration optimizes bidirectional gating recurrent unit's network hyperparameters. To tackle estimation errors, a multi‐layer perceptron combined with sequential model‐based algorithmic configuration is employed to create a classification model that automatically discerns the quality of estimates. Subsequently, an innovative correction model, based on grey relevancy degree and relevancy errors, is devised to rectify erroneous estimates. The final estimates result from a summation of the initial estimates and the values derived from error corrections. By analysing the real data from a wind farm in northwest China, a simulation test validates the proposed hybrid model. Experimental results demonstrate a substantial improvement in modelling accuracy when compared to the initial model.

Coordinating Demand Response and Wind Turbine Controls for Alleviating the First and Second Frequency Dips in Wind-Integrated Power Grids

This paper introduces a method employing demand response (DR) and wind turbine (WT) to decrease the first and second frequency dips in power systems with the massive proliferation of wind resources. Inverter air conditioners (IACs) are utilized to participate in the DR program. The buildings' thermal model and the IACs' electrical model are integrated to characterize a relation between power system frequency and IACs regulation power. An adaptive delay controller (ADC) is presented to capture the command communication delays from the DR controller to IACs. In addition, a controller is suggested to adopt wind power plants in system frequency regulation. This controller rises the wind plant output power for some seconds and returns it, following frequency recovery, to the initial power. The recovery period causes the second frequency dip, in response to which, a method is introduced to identify the moment of the second dip and alleviate it via DR.

Integrated strategy for real-time wind power fluctuation mitigation and energy storage system control

To address the impact of wind-power fluctuations on the stability of power systems, we propose a comprehensive approach that integrates multiple strategies and methods to enhance the efficiency and reliability of a system. First, we employ a strategy that restricts long- and short-term power output deviations to smoothen wind power fluctuations in real time. Second, we adopt the sliding window instantaneous complete ensemble empirical mode decomposition with adaptive noise (SW-ICEEMDAN) strategy to achieve real-time decomposition of the energy storage power, facilitating internal power distribution within the hybrid energy storage system. Finally, we introduce a rule-based multi-fuzzy control strategy for the secondary adjustment of the initial power allocation commands for different energy storage components. Through simulation validation, we demonstrate that the proposed comprehensive control strategy can smoothen wind power fluctuations in real time and decompose energy storage power. Compared with traditional empirical mode decomposition (EMD), ensemble empirical mode decomposition (EEMD), and complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) decomposition strategies, the configuration of the energy storage system under the SW-ICEEMDAN control strategy is more optimal. Additionally, the state-of-charge of energy storage components fluctuates within a reasonable range, enhancing the stability of the power system and ensuring the secure operation of the energy storage system.

Simulations and models for the Richtmyer–Meshkov instability with broadband perturbations

The Richtmyer–Meshkov instability (RMI) is shock driven and affects many phenomena from inertial fusion to supernova explosions. The behavior of single-modes in the RMI has been studied extensively but less is known with the broadband perturbations that occur in applications. Here, we describe extensive numerical simulations and modeling of the RMI with broadband perturbations with an initial power spectrum of the form P ∝ km, where k is the wavenumber. The hydrodynamic condition is the same as in the θ-Group Collaboration [Thornber et al., “Late-time growth rate, mixing, and anisotropy in the multimode narrowband Richtmyer–Meshkov instability: The θ-group collaboration,” Phys. Fluids 29, 105107 (2017)] with a Mach ∼1.86 shock and gamma-law = 5/3 fluids with Atwood number A = −0.5. The bubble amplitude hB is found to grow in two stages. Initially, hB undergoes a phase-inversion and grows linearly in time (t) at a rate consistent with a linear theory. Asymptotically, hB grows as a power law ∼tθ when k|hB| > O(1), where k is the average wavenumber for the initial spectrum. The RMI behavior in simulations and modeling agree over a wide range of exponent m, spectral width, initial amplitude, and time. The agreement is quantified objectively using statistical analysis.

Effectiveness of poly(methyl methacrylate) spray encapsulation for perovskite solar cells

For commercial applications, Perovskite Solar Cells (PSCs) need to be well encapsulated to improve long term stability. The most common method, glass-glass encapsulation, uses edge sealant materials to encapsulate the device between sheets of glass. Glass-Glass encapsulation, while providing provide adequate protection from the ambient environment, limits the use of flexible substrates for thin film solar cells due to its rigidity. Additionally, the added weight of glass encapsulation reduces the specific power (W kg−1) of PSCs, which is an important factor when designing solar cells for aerospace applications. Here we demonstrate that commercially available acrylic spray encapsulation offers efficient and robust stability for PSCs. It is shown that applying the encapsulation via this method does not degrade the PSCs, unlike other literature and glass-glass encapsulation methods. Additionaly, it is shown that 1 coat of acrylic spray encapsulation has an effective thickness of ∼1.77 µm and a weight of ∼6 mg. For stability measurements, PSCs with an acrylic coating show a 4% increase in performance after ∼730 h under dark storage conditions and retain 88% of their initial power conversion efficiency after 288 h under 85% relative humidity 25 °C. We anticipate our assay to be a starting point for further studies into spray encapsulation materials and methods not just for terrestial applications, but for aerospace applications as well.

Enhanced Wall‐Plug Efficiency over 2.4% and Wavelength Dependence of Electrical Properties at Far UV‐C Light‐Emitting Diodes on Single‐Crystal AlN Substrate

Herein, the wavelength dependence of the efficiency and the lifetime of far UV‐C light‐emitting diodes (LEDs) on a single‐crystal AlN substrate is systematically analyzed from experiments and simulations. A positive relation between efficiency and emission wavelength is observed. The wall‐plug efficiency reaches 0.47, 1.0, 2.1, and 2.4% at 227, 230, 233, and 235 nm wavelengths, respectively. The simulation results show that carrier injection plays a critical role in the efficiency change in the far UV‐C region rather than in the internal quantum or light extraction efficiency. The lifetime test clearly demonstrates a trade‐off between the L70 lifetime and the emission wavelength, although the initial optical power increases with the longer wavelength. The measurement results under various wavelengths and stress currents indicate that the carriers injected in quantum wells motivate power reduction during current stress. Moreover, the internal quantum efficiency affects the degradation rate because the influence of defects becomes stronger during stress. Finally, the reliability of a 231 nm LED is investigated at a reduced current of 35 mA. The projected L70 and L50 lifetimes are 11 000 and 28 000 h, respectively, from the fitting model based on the defect generation during aging.

Experimental study on enhanced heat transfer performances and optimized strategies of cascade sensible-latent heat storage radiator

Improving the thermal efficiency of radiator and minimizing the energy loss in distribution networks are crucial for space heating. However, existing studies primarily focused on optimizing the thermal performance or indoor environment of individual units, yet rarely revealed the enhanced heat transfer performance from initial power supply to final heat utilization. To address this gap, this study developed a cascade sensible-latent heat storage radiator, and improved the thermal performance in the following ways. Firstly, by adsorbing paraffin wax with expanded graphite, the thermal conductivity rose from 0.2 to 3.5 W/(m‧K). Secondly, through cascading sensible and latent heat storage bricks, the heat charging/discharging efficiency increased by 11.9 %/14.6 %. Finally, by enhancing the airflow from 0.05 to 0.28 m/s, the heat discharging efficiency and entransy dissipation amount increased by 15.8 % and 225.8 kJ‧K, respectively. The total energy utilization efficiency was improved by 7.4 %, and the dissatisfaction caused by draft and noise both met the personnel requirement. The total annual cost of developed radiator was merely 30 % and 60 % of the direct electric heating radiator and sensible heat storage radiator, respectively. Therefore, the sensible-latent heat storage radiator offered advantages in improving the energy utilization efficiency, indoor thermal environment and cost effectiveness performance.

Smartphone Fast Charger Analysis Based on RLC Circuit Transient Process

In today's era, the widespread adoption of mobile terminals, particularly smartphones, has been facilitated by the rapid advancements in information and communication technology. However, a notable drawback of smartphones is their high-power consumption, necessitating faster charging solutions to enhance user convenience. This paper focuses on the RLC circuit of fast chargers. Initially, it introduces the fundamental principles and associated protocols of fast charging technology, elucidating the operation of integrated circuits within fast chargers and highlighting the advantages of fast charging compared to conventional slow charging methods. Moreover, the paper conducts an in-depth analysis of the transient processes within the pivotal series RLC circuit in fast chargers, encompassing zero-input responses and sinusoidal AC excitation responses. The transient processes are categorized into overdamped, critically damped, or underdamped states based on circuit element parameters, with initial conditions and power supply phase determining whether the circuit transitions directly into a steady-state process when stimulated by sinusoidal AC. This research contributes to a deeper understanding of the RLC circuit within smartphone fast chargers and serves as a valuable reference for advancing the development of fast charging solutions.

Nitrogen- and fluorine-doped bimetallic carbide as active and stable oxygen reduction reaction electrocatalyst

Nitrogen- and fluorine-doped bimetallic carbide composites with graphite matrix (abbreviated as C19Cr7Mo24/NG and C19Cr7Mo24/FG) are synthesized through carbonization at 1300 °C. The C19Cr7Mo24/NG displays an initial half-wave potential (E1/2) of 0.873 V and suffers merely 3 mV decrease in E1/2 within 60,000 CV cycles for oxygen reduction reaction (ORR) in alkaline media. A H2/O2 fuel cell testing system using the C19Cr7Mo24/NG as cathode maintains 95.9% of the initial peak power density (1.08 W cm−2) within 60,000 cycles. The C19Cr7Mo24/FG shows higher ORR activity than the C19Cr7Mo24/NG. The positive and negative charge centers caused by the N or F dopants are the critical reasons to their high activities. While F and bimetallic carbide more favor electron transfer respectively than the N and monometallic carbide. Their excellent stabilities originate from interactions among atoms due to electron transfer and the intrinsic chemical inertness of graphite and bimetallic carbides.

The Effective Field Theory of Large-scale Structures of a Fuzzy Dark Matter Universe

Ultralight scalar fields and their noninteracting class, i.e., the so-called fuzzy dark matter (FDM), are dark matter candidates introduced to solve the small-scale problems of the standard cold dark matter. In this paper, we investigate whether the physics of FDM, particularly the quantum pressure that leads to the suppression of structure formation on small scales, could leave significant imprints on the large-scale statistics of matter fluctuations. For this purpose, we utilize the Effective Field Theory of Large Scale Structures (EFT of LSS), wherein small-scale physics is integrated and represented on large scales by only a set of free parameters. These parameters can be determined by fitting them into the cosmological simulations. By fitting the EFT predictions to the simulation data, we determine the value of the speed of sound as a quantitative measure of how UV physics affects large-scale perturbation. We use the Gadget-2 code to study the evolution of 5123 particles in a box with a side length 250 h −1 Mpc. We exploit the suppressed FDM initial power for the FDM universe and perform N-body simulation sufficient to produce accurate—enough for our purpose—results on large scales. In particular, we perform three FDM simulations with different masses and compare their sound speed with the standard cold dark matter (CDM) simulation. We found no difference between the FDM and CDM sound speeds beyond the confidence intervals. However, a consistently increasing trend can be seen in the sound speed for lower masses. This result suggests further investigations using higher-resolution simulations.

Enhancing UV Stability of Perovskite Solar Cells with Transparent Fluorinated Polyimide

Ultraviolet (UV)-induced degradation is one of the major problems in the field of perovskite solar cells (PSCs). Therefore, exploring materials and techniques to prevent UV light from penetrating into the device is urgently necessary. Here, we developed a special transparent fluorinated polyimide (FPI) resin, which can be directly spin-coated on the front side of conventional indium-doped tin oxide substrates (glass/ITO). Most aromatic polyimides strongly absorb visible light and are colored. The FPI we designed and synthesized bears electron-acceptor CF 3 - groups, which reduces the intra-/intermolecular charge-transfer (CT) effect, enabling FPI to possess high transmittance in the visible range while completely blocking UV light. As a result, the FPI coating slightly pulls down the initial power conversion efficiency (PCE) (21.02% to 20.19%). Remarkably, the coating significantly improves the PSC UV stability. Upon an 8-h enhanced UV aging test in air, the FPI/glass/ITO-based PSC is able to retain 85.0% of its initial PCE. In contrast, the control device (glass/ITO-based PSC) only keeps 40.9% of its initial PCE. The protective effect of FPI is even more prominent in current popular 3D/2D high-performance PSCs because UV light can seriously damage the 2D layer. The unencapsulated 3D/2D device based on FPI/glass/ITO substrate has a very high PCE retention of up to 80% after 12-h enhanced UV aging test in air, comparing to 36% for the control 3D/2D device without FPI. This work demonstrates that FPI and its possible derivatives could provide a feasible avenue to handle UV-induced degradation for PSCs effectively.