Electron Loss Research Articles

Properties of Relativistic Bouncing Microbursts

AbstractMicrobursts are short duration intensifications in precipitating electron flux that are believed to be a significant contributor to electron losses in the magnetosphere. Microbursts have been observed in the form of bouncing electron packets, which offer a unique opportunity to study their properties and importance as a loss process. We present a collection of bouncing microbursts observed by the HILT instrument on SAMPEX from 1994 to 2004. We analyze the locations of the bouncing microbursts in L and MLT and find they align well with the properties of relativistic microbursts as a whole. We find that the majority of bouncing microbursts observed by SAMPEX have scale sizes of ∼30 km at the point of observation, or ∼300 km when mapped to the magnetic equator. The time separation between the peaks of these bouncing microbursts is usually either half a bounce period or a whole bounce period.

Asymmetrical changes of electron-donating and electron-accepting capacities of natural organic matter during its interaction with Fe oxyhydroxides

The electron gain and loss of natural organic matter (NOM) plays an important role in the biogeochemical cycling of element and contaminant attenuation. The electron-donating capacity (EDC) and electron-accepting capacity (EAC) of NOM determine its electron exchange ability. However, the influences of bonded matrices on EDC and EAC of NOM remain unclear. Here we investigated the variations in EDC and EAC of NOM during its interaction with Fe oxyhydroxides. Compared to original NOM, the presence of Fe oxyhydroxides slightly decreased the EDC of dissolved NOM by 0.58–2.08 mmol e−/g C and of adsorbed NOM by 0.33–2.67 mmol e−/g C. However, the EAC of dissolved NOM and adsorbed NOM significantly (p < 0.05) increased by 1.92–14.17 and 3.08–36.67 mmol e−/g C, respectively. The excessive increase of EAC was mainly attributed to changes in NOM chemical components, particularly increases in oxidative components such as Fe(III) and quinonoid carbonyls, rather than changes in EDC. For dissolved NOM, the heightened EAC was mainly attributed to the complexation of Fe(III) by carboxyl in NOM. For adsorbed NOM, the boosted EAC was predominantly linked to the enrichment of quinonoid carbonyl through the selective molecular fractionation and the oxidative polymerization of polyphenols in NOM. Our finding highlights the previously overlooked phenomenon of asymmetrical changes of EDC and EAC of NOM during its interaction with Fe oxyhydroxides. The increased EAC could potentially affect various biogeochemical processes, such as methane production, anaerobic ammonium oxidation and microbial Fe(III) reduction.

Uncovering the potential of industrial waste: turning discarded resources into sustainable advanced materials

To identify solutions for utilizing industrial wastes (slag, sludge, fly ash, and bottom ash) in the development of pro-environmental systems, this paper reviews existing literature and explores material characterization methods. A review analysis was conducted to uncover their potential, and it was found that many utilizations can be made to recycle them into sustainable materials. Structure characterization, optical-dielectric function, and morphology analysis were analyzed to confirm the recent review. Structural properties are represented by crystallite size and crystallinity, where nickel slag shows the smallest distribution (55 ± 10) nm with the highest crystallinity (25.42%), indicating its association with uniformity of response to external disturbances and micro-structural stability. From the analysis of optical and dielectric functions via Kramers Kronig relation, the widening of ∆(LO−TO) was shown by fly ash and slag indicating stable bonding suitable as x-ray shielding and sensor, while high electron loss functions were shown by sludge and bottom ash indicating high potential electronic transition performance. Based on their chemical and physical properties, these industrial wastes are not limited as construction materials and can even be upgraded to more advanced development materials.

Global Survey of Energetic Electron Precipitation at Low Earth Orbit Observed by ELFIN

AbstractWe statistically evaluate the global distribution and energy spectrum of electron precipitation at low‐Earth‐orbit, using unprecedented pitch‐angle and energy resolved data from the Electron Losses and Fields INvestigation CubeSats. Our statistical results indicate that during active conditions, the ∼63 keV electron precipitation ratio peaks at L &gt; 6 at midnight, whereas the spatial distribution of precipitating energy flux peaks between the dawn and noon sectors. ∼1 MeV electron precipitation ratio peaks near midnight at L &gt; ∼6 but is enhanced near dusk during active times. The energy spectrum of the precipitation ratio shows reversal points indicating energy dispersion as a function of L shell in both the slot region and at L &gt; ∼6, consistent with hiss‐driven precipitation and current sheet scattering, respectively. Our findings provide accurate quantification of electron precipitation at various energies in a broad region of the Earth's magnetosphere, which is critical for magnetosphere‐ionosphere coupling.

BARREL Observations of Microburst Events With a Slowly‐Varying Component

AbstractElectron microburst precipitation has been shown to have significant potential for depletion of the outer radiation belt. We present observations from the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) of six (five unique and one dual‐balloon observation) microburst events, each containing minutes to hours of persistent microbursts. We find that each event included a slowly‐varying smooth precipitation component underlying the bursty component. The smooth component has not yet been fully characterized in the literature; we have written a program to identify microburst events and quantify the relative contributions of each component in the BARREL data. In all six events analyzed, the smooth component contributed more to the total X‐ray counts measured, indicating that the smooth component could contribute significantly to radiation belt loss.

Highly efficient microbial inactivation enabled by tunneling charges injected through two-dimensional electronics.

Airborne pathogens retain prolonged infectious activity once attached to the indoor environment, posing a pervasive threat to public health. Conventional air filters suffer from ineffective inactivation of the physics-separated microorganisms, and the chemical-based antimicrobial materials face challenges of poor stability/efficiency and inefficient viral inactivation. We, therefore, developed a rapid, reliable antimicrobial method against the attached indoor bacteria/viruses using a large-scale tunneling charge-motivated disinfection device fabricated by directly dispersing monolayer graphene on insulators. Free charges can be stably immobilized under the monolayer graphene through the tunneling effect. The stored charges can motivate continuous electron loss of attached microorganisms for accelerated disinfection, overcoming the diffusion limitation of chemical disinfectants. Complete (>99.99%) and broad-spectrum disinfection was achieved <1 min of attachment to the scaled-up device (25 square centimeters), reliably for 72 hours at high temperature (60°C) and humidity (90%). This method can be readily applied to high-touch surfaces in indoor environments for pathogen control.

Relativistic Electron Precipitation Events Driven by Solar Wind Impact on the Earth's Magnetosphere

AbstractCertain forms of solar wind transients contain significant enhancements of dynamic pressure and may effectively drive magnetosphere dynamics, including substorms and storms. An integral element of such driving is the generation of a wide range of electromagnetic waves within the inner magnetosphere, either by compressionally heated plasma or by substorm plasma sheet injections. Consequently, solar wind transient impacts are traditionally associated with energetic electron scattering and losses into the atmosphere by electromagnetic waves. In this study, we show the first direct measurements of two such transient‐driven precipitation events as measured by the low‐altitude Electron Losses and Fields Investigation CubeSats. The first event demonstrates storm‐time generated electromagnetic ion cyclotron waves efficiently precipitating sub‐relativistic and relativistic electrons from &gt;300 keV to 2 MeV at the duskside. The second event demonstrates whistler‐mode waves leading to scattering of electrons from 50 to 700 keV on the dawnside. These observations confirm the importance of solar wind transients in driving energetic electron losses and subsequent dynamics in the ionosphere.

Statistical Properties of Exohiss Waves and Associated Scattering Losses of Radiation Belt Electrons

AbstractExohiss waves are a type of structureless whistler‐mode waves that exist in the low density plasmatrough outside the plasmapause and may potentially perturb the motions of electrons in the radiation belt and ring current. Using data from Van Allen Probe A, we analyze the distribution of magnetic power spectral density (PSD) of exohiss waves in different magnetic local time (MLT) and L‐shell regions near the geomagnetic equator. The results reveal that the peak magnetic PSD of exohiss waves is the weakest at MLT = 0–6 and the strongest at MLT = 12–18. The magnetic PSDs of exohiss waves are much lower than those of chorus and hiss waves except for the MLT = 12–18 sector. In addition, we calculated the quasi‐linear bounce‐averaged pitch angle and momentum diffusion coefficients (〈Dαα〉 and 〈Dpp〉) of electrons caused by exohiss waves. The diffusion coefficients are then compared with those caused by chorus and hiss waves. The peak 〈Dαα〉 of electrons driven by exohiss waves becomes stronger as L‐shell increases at all MLTs and is the greatest on the dayside, especially in the sector of MLT = 12–18. Exohiss waves have more significant effect on the loss of radiation belt electrons with specific energy levels related to MLT and L‐shell region compared to chorus and hiss waves. On the other hand, 〈Dpp〉 of electrons caused by exohiss waves is very small, which illustrates that exohiss waves have almost no acceleration effect on electrons.

Competition between Transport and Recombination in Dye Solar Cells at Low Light Intensity

The efficiency of electron collection in a dye‐sensitized solar cell (DSC) is determined by a delicate balance between electronic transport and recombination losses caused by electron transfer to dye cations and electron acceptors. While state‐of‐the‐art DSCs have demonstrated quantitative electron collection under standard 1 sun conditions, the nonlinear nature of the trapping/detrapping dynamics in the photoanode with respect to the stored electronic charge can result in suboptimal performance under the low illumination intensity conditions commonly found indoors. Herein, the key factors influencing electron collection in relation to light intensity using impedance spectroscopy and numerical analysis are thoroughly examined. Impedance analysis reveals that the electron diffusion length tends to decrease as the quasi‐Fermi level is lowered, approaching the critical limit (Ln/d ≈ 1) at intensities characteristic of indoor illumination. A range of tert‐butyl pyridine concentrations and different thermal and chemical treatments of the TiO2 are tested, showing that this low intensity limitation is inherent to the multiple‐trapping mechanism that governs the functioning of a DSC. It is concluded that relatively high ideality factors, nonoptimal electrolyte compositions, or small variations in the quality of the TiO2 layer can result in electron collection limitations that are not apparent under 1 sun but become noticeable at low light intensities.

Developing hybrid systems to address oxygen uncoupling in multi-component Rieske oxygenases

Rieske non-heme iron oxygenases (ROs) are redox enzymes essential for microbial biodegradation and natural product synthesis. These enzymes utilize molecular oxygen for oxygenation reactions, making them very useful biocatalysts due to their broad reaction scope and high selectivities. The mechanism of oxygen activation in ROs involves electron transfers between redox centers of associated protein components, forming an electron transfer chain (ETC). Although the ETC is essential for electron replenishment, it carries the risk of reactive oxygen species (ROS) formation due to electron loss during oxygen activation. Our previous study linked ROS formation to O2 uncoupling in the flavin-dependent reductase of the three-component cumene dioxygenase (CDO). In the present study, we extend this finding by investigating the effects of ROS formation on the multi-component CDO system in a cell-free environment. In particular, we focus on the effects of hydrogen peroxide (H2O2) formation in the presence of a NADH cofactor regeneration system on the catalytic efficiency of CDO in vitro. Based on this, we propose the implementation of hybrid systems with alternative (non-native) redox partners for CDO, which are highly advantageous in terms of reduced H2O2 formation and increased product formation. The hybrid system consisting of the RO-reductase from phthalate dioxygenase (PDR) and CDO proved to be the most promising for the oxyfunctionalization of indene, showing a 4-fold increase in product formation (20 mM) over 24 h (TTN of 1515) at a 3-fold increase in production rate.

GRB 221009A: Spectral Signatures Based on ALPs Candidates

GRB 221009A has posed a significant challenge to our current understanding of the mechanisms that produce TeV photons in gamma-ray bursts (GRBs). On one hand, the Klein–Nishina (KN) effect of the inverse Compton scattering leads to less efficient energy losses of high-energy electrons. On the other hand, at a redshift of 0.151, the TeV spectrum of GRB 221009A undergoes significant absorption by the extragalactic background light (EBL). Therefore, the observation of a 13 TeV photon in this event implies the presence of enormous photon fluxes at the source, which the synchrotron self-Compton mechanism in external shocks cannot easily generate. As an alternative, some authors have suggested the possibility of converting the TeV photons into axion-like particles (ALPs) at the host galaxy, in order to avoid the effects of EBL absorption, and then reconverting them into photons within the Milky Way. While this solution relaxes the requirement of very high photon fluxes, the KN effect still poses a challenge. Previously, we have shown that the injections of ALPs could explain the observation of 13 TeV photons. Here, we include the energy dependence of the probability of survival and the amount of energy carried to determine the ALP candidates, which could potentially explain the TeV photons observed by the Large High Altitude Air Shower Observatory and their hard spectrum. We found that the allowed candidates are generally clustered around masses of 10−7 eV. We also considered different EBL models, for the one predicting larger attenuation tends to reject ALP candidates with the lowest coupling factor. For some hypotheses of the EBL model, these candidates are found below a region of the parameter space in which, if detected, ALPs could account for all of the cold dark matter in the Universe.

Molecular insights into the interaction mechanism of triethylenetetramine target-deposited quartz from smithsonite in carbonate ionic liquids and its adsorption on minerals

In order to induce alterations in the mineral surface’s hydrophobicity and subsequently separate smithsonite from quartz, the current study introduces an innovative amine depressant termed triethylenetetramine (TETA). Micro-flotation experiments clearly demonstrated that adding a relatively modest dosage (20 mg/L) of TETA at pH 10 reduced the recovery of quartz from 92.2 % to 22.5 % without reducing the recovery of smithsonite. ICP-OES and zeta potentials revealed that TETA selectively adsorbed on the quartz surface effectively reduced Zn2+ dissolution and altered the setting of the quartz surface to preferentially adsorb NaOL on the smithsonite surface. X-ray photoelectron spectroscopy (XPS) and Quartz crystal microbalance with dissipation (QCM-D) analyses support that TETA is more susceptible to Zn atoms in Zn5(OH)6(CO3)2(s) through a bonding process and preferentially chemisorbs on the quartz surface to the exclusion of Zn-CO3 on the smithsonite surface. Density functional theory (DFT) calculations revealed that electron acceptance by Zn and electron loss by N resulted in hybridization reactions between Zn 2 s, 3d, 4p and N 2p orbitals to form stable Zn-N covalent bonds. Chemical bonds characterized by ionic bonding were formed between TETA and Zn atoms on the cleavage plane of smithsonite, which led to the susceptibility of TETA adsorption on the surface of smithsonite to be broken.

Precise Regulation in Chain-Edge Structural Microenvironments of 1D Covalent Organic Frameworks for Photocatalysis.

Covalent organic frameworks (COFs) constitute a promising research topic for photocatalytic reactions, but the rules and conformational relationships of 1D COFs are poorly defined. Herein, the chain edge structure is designed by precise modulation at the atomic level, and the 1D COFs bonded by C, O, and S elements is directionally prepared for oxygen-tolerant photoinduced electron transfer-atom transfer radical polymerization (PET-ATRP) reactions. It is demonstrated that heteroatom-type chain edge structures (─O─, ─S─) lead to a decrease in intra-plane conjugation, which restricts the effective transport of photogenerated electrons along the direction of the 1D strip. In contrast, the all-carbon type chain edge structure (─C─) with higher intra-plane conjugation not only reduces the energy loss of photoexcited electrons but also enhances the carrier density, which exhibits the optimal photopolymerization performance. This work offers valuable guidance in the exploitation of 1D COFs for high photocatalytic performance. This work offers valuable guidance in the exploitation of 1D COFs for high photocatalytic performance.

Variation of chemical ordering induced by grain boundaries in multi-principal element alloys

Cr segregation at grain boundary (GB) of Multi-principal element alloys (MPEAs) is extensively observed and holds significance in physical processes, e.g., oxidation, but its atomic-level mechanism is still debated. Here, correlations among atomic-level volume, electronegativity, charge transfer, and atomic stress, are systematically investigated in equiatomic CrFeCoNi alloys, both with and without GBs. The correlations slightly disturbed in GBs inadequately elucidate the discrepancy of Cr short range ordering (SRO) in the interior grain and at GBs. High excess free volume inherent in GBs, distinguishing from the interior, is a crucial factor, driving Cr enrichment by means of the mitigation of electron loss and the alleviation of very high tensile stress. The stress mechanism in conjunction with the electronegativity of element and the characteristics of GB structure, not only adapts to Cr segregation in CrFeCoNi, but also to other element of low electronegativity within considered alloys.

Sub‐MeV Electron Precipitation Driven by EMIC Waves Through Nonlinear Fractional Resonances

AbstractElectromagnetic ion cyclotron waves in the Earth's outer radiation belt drive rapid electron losses through wave‐particle interactions. The precipitating electron flux can be high in the hundreds of keV energy range, well below the typical minimum resonance energy. One of the proposed explanations relies on nonresonant scattering, which causes pitch‐angle diffusion away from the fundamental cyclotron resonance. Here we propose the fractional sub‐cyclotron resonance, a second‐order nonlinear effect that scatters particles at resonance order n = 1/2, as an alternate explanation. Using test‐particle simulations, we evaluate the precipitation ratios of sub‐MeV electrons for wave packets with various shapes, amplitudes, and wave normal angles. We show that the nonlinear sub‐cyclotron scattering produces larger ratios than the nonresonant scattering when the wave amplitude reaches sufficiently large values. The ELFIN CubeSats detected several events with precipitation ratio patterns matching our simulation, demonstrating the importance of sub‐cyclotron resonances during intense precipitation events.

The Compton Energy Loss of Electrons in Storage Rings

We examine, in general, the energy loss of electrons caused by the Compton scattering of electrons on black body photons in the storage rings. We derive the scattering rate of electrons in the Planckian photon sea and then the energy loss of electrons per unit length. We discuss possible generalization of our method in particle physics and consider a possible application of our formulas in case of motion of charged particles in the relic cosmological radiation.

Large Amplitude Whistler Waves in Earth's Plasmasphere and Plasmaspheric Plumes

AbstractWhistler mode waves in the plasmasphere and plumes drive significant losses of energetic electrons from the Earth's radiation belts into the upper atmosphere. In this study, we conducted a survey of amplitude‐dependent whistler wave properties and analyzed their associated background plasma conditions and electron fluxes in the plasmasphere and plumes. Our findings indicate that extremely large amplitude (&gt;400 pT) whistler waves (a) tend to occur at L &gt; 4 over the midnight‐dawn‐noon sectors and have small wave normal angles; (b) are more likely to occur during active geomagnetic conditions associated with higher fluxes of anisotropic electrons at 10 s keV energies; and (c) tend to occur at higher latitudes up to 20° with increasing amplitude. These results suggest that extremely large amplitude whistler waves in the plasmasphere and plumes could be generated locally by injected electrons during substorms and further amplified when propagating to higher latitudes.

Insight into the role of reactive species on catalyst surface underlying peroxymonosulfate activation by P–Fe2MnO4 loaded on bentonite for trichloroethylene degradation

In this study, bentonite supporting phosphorus-doped Fe2MnO4 (BPF) was synthesized and applied for PMS activation to degrade TCE. Morphology and structure characterization results indicated the successfully synthesized of BPF, and the BPF/PMS system not only featured high TCE removal (97.4%) but also high reaction rate constant (kobs = 0.0554 min−1) and PMS utilization (70.4%, kobs = 0.0228 min−1). According to the results of various experiments, massive oxygen vacancies on P–Fe2MnO4 alter its charge balance and facilitate the electron transfer process named adjacent transfer (direct electron capture by adsorbed PMS from adjacent TCE). Mn(III) is the main adsorption site for PMS, and the hydroxyl groups on the catalyst (Fe sites of P–Fe2MnO4, Si and Al sites of bentonite) can also offer binding sites for PMS. The hydrogen-bonded PMS on Fe(III) and Mn(III) sites will subsequently accept the discharged electrons to generate free radicals and high-valent metal species. Meanwhile, electron loss of HSO5− that chemically bonded to hydroxyl groups on bentonite will generate SO5•−, which will further produce 1O2 through self-bonding. the active species on the catalyst surface contribute 65% of TCE degradation in the heterogeneous catalytic oxidation system.

Insulator-on-Conductor Fouling Amplifies Aqueous Electrolysis Rates.

The chemical industry is a major consumer of fossil fuels. Several chemical reactions of practical value proceed with the gain or loss of electrons, opening a path to integrate renewable electricity into chemical manufacturing. However, most organic molecules have low aqueous solubility, causing green and cheap electricity-driven reactions to suffer from intrinsically low reaction rates in industry's solvent of choice: water. Here, we show that a strategic, partial electrode fouling with hydrophobic insulators (oils and plastics) offsets kinetic limitations caused by poor reactant solubility, opening a new path for the direct integration of renewable electricity into the production of commodity chemicals. Through electrochemiluminescence microscopy, we reveal for the oxidation of organic reactants up to 6-fold reaction rate increase at the "fouled" oil-electrolyte-electrode interface relative to clean electrolyte-electrode areas. Analogously, electrodes partially masked (fouled) with plastic patterns, deposited either photolithographically (photoresists) or manually (inexpensive household glues and sealants), outperform clean electrodes. The effect is not limited to reactants of limited water solubility, and, for example, net gold electrodeposition rates are up to 22% larger at fouled than clean electrodes. In a system involving a surface-active reactant, rate augmentation is driven by the synergy between insulator-confined reactant enrichment and insulator-induced current crowding, whereas only the latter and possibly localized decrease in iR drop near the insulator are relevant in a system composed of non-surface-active species. Our counterintuitive electrode design enhances electrolysis rates despite the diminished area of intimate electrolyte-electrode contact and introduces a new path for upscaling aqueous electrochemical processes.

Synthesis &amp; Characterization of Carbon Nanostructures.

Synthesis In this research a study was conducted on the Synthesis and dimensional structural characterization of nanostructures consisting of Graphene, Nanotubes and Fullerenes C60 and C70 carbon research project consists of a synthesis and characterization in its theoretical and experimental framework to test yields in the synthesis of each nanostructure. Synthesis for Multiple Synthesis Rector MSR will be held in the exploder and electric fields in the toroidal coil Tesla coil. As for the structural dimensional characterization of nanostructured materials carbon is carried out by Raman spectroscopy, diffraction X-ray (XRD) and Transmission Electron Microscopy (TEM) Scanning Electron Microscopy (SEM) Atomic Force Microscopy (AFM) and EELS (Energy Electron loss Spectrum). Justification Synthesis System The main justification synthesis system is to generate nanostructures (Nanotubes, Nanofibers, Fullerenes, graphene) easily and economically; all using little equipment and a simple process which is reflected in lower costs simple synthesis as current processes are very expensive and too complex. Justification Synthesis System The main objective of this system is the generation synthesis of nanostructures by using a Tesla coil (Plasma Generator) as the main component of the system being accessible, simple and inexpensive technology. Another goal is to optimize the generation of nanostructures to its widespread use in industry, nanotechnology and materials science. Through a system very inexpensive and simple synthesis.