Heavy Ion Research Articles

Generalized and Scalable Synthesis of Manganese Dioxide-Based Tubular Micromotors for Heavy Metal Ion Removal.

Synthetic nano- and micromachines hold immense promise in biomedicine and environmental science. Currently, bubble-driven tubular micro/nanomotors have garnered increasing attention owing to their exceptional high-speed self-propulsions. However, complex and low-yield preparation methods have hindered their widespread applications. Herein, we present a generalized, scalable, and low-cost electrospinning-based strategy to fabricate MnO2-based composite tubular micromotors (MnO2-TMs) for efficient heavy metal ion removal. The inherent flexibility of precursor nanofibers derived from diverse matrix materials enables the creation of MnO2-TMs with a wide range of morphologies. In response to morphology changes, the MnO2-TMs, based on a bubble-propelled mechanism, exhibit multimodal motion patterns, including linear, circular, and spiral to stochastic swinging. To elucidate the underlying morphology-to-motion relationship, we conducted systematic simulations of fluid dynamics around the MnO2-TMs. Furthermore, by incorporation of Fe3O4 nanoparticles, the capabilities of MnO2-TMs can be expanded to include magnetic manipulation for directional navigation and efficient retrieval. Benefiting from these attributes, MnO2-TMs excel in removing heavy metal ions from water. The developed MnO2-MnWO4@Fe3O4 TMs exhibit prominent adsorption capacities of 586.5 mg g-1 for Cu2+ and 156.4 mg g-1 for Pb2+. Notably, the magnetic property facilitates rapid separation and retrieval of the micromotors, and the absorbed ions can be simply recovered by pH adjustment. This work establishes a general framework for developing MnO2-based tubular micro/nanomotors to address environmental challenges.

Optimization of the Electron Spectrometer Telescope geometry for the PRESET satellite through Monte Carlo simulation

The Electron Spectrometer Telescope (EST) aboard the PRESET satellite mission aims to measure the pitch angle distribution of 0.3–4 MeV electrons in the outer Van Allen belts. The PRESET satellite is planned to launch into a sun-synchronous low Earth orbit in Q2, 2026. We present comprehensive Monte Carlo simulations to optimize the design and response of the EST instrument. The EST consists of a stack of silicon strip detectors and a collimator to take pitch-angle dependent electron spectral measurements with a target angular resolution of 6° while rejecting the proton, heavy ion and gamma detection events. Various collimator designs and detector stacking configurations are investigated using the Geant4 code to deduce an optimal design and configuration. For validation of the Geant4 simulations, a benchmark test spectrometer was set up using a stack of four silicon detectors and a good agreement between the measured and simulated responses was found for a beta spectrum from a 90Sr/90Y source. The collimator design was optimized by adjusting total length, aperture size, number of view-ports and collimator materials. The optimum aperture size and the number of view-ports were determined by varying them and selecting the best cases that meet the angular resolution and the geometric factor requirements. Moreover, to address the under-utilization of the front position-sensitive detector encountered in a typical pin-hole collimator, two offset collimators with tilted axes were employed. Extensive simulations were carried out by varying the number of silicon detectors and the thickness of each detector to optimize the configuration of the silicon detector stack. An optimum thickness of the front detector was found to be 140 µm, which can minimize the perturbation counts caused by the proton detection events. For the other detectors, a stack of four 1.5 mm thick detectors was chosen to achieve a good sensitivity to low energy electrons at a tolerable complexity of the system. The angular response simulated for the optimum design of the EST showed a resolution of 5.5°, which is slightly better than the target resolution of 6°. The response matrices of the final design simulated for isotropic electron and proton fields showed a high geometric factor, which is expected to produce an average electron counting rate of 230 cps within the trapped region with a negligible contamination of the electron spectrum by protons except for a mild contamination by the 1.0–1.1 MeV protons.

Design of Recyclable Adsorbent for Water Pollutants Based on Chitosan-Coated Carboxymethyl Cellulose-Calcium Alginate Wrapped Iron Oxide-Copper Oxide Composite Beads

ABSTRACT In this study, an efficient nanocomposite based on calcium alginate-carboxymethyl cellulose/iron oxide-copper oxide (CA-CMC/Fe2O3-CuO) is developed in beads form and utilized as nanoadsorbent and nanocatalyst. Further, the beads were coated with chitosan, resulting in Cs@CA-CMC/Fe2O3-CuO beads. The prepared beads exhibited exceptional adsorption capabilities for selected heavy metal ions. Notably, the Cs@CA-CMC/Fe2O3-CuO beads displayed remarkable adsorption among the other beads toward the three selected metal ions. Ag(I) was highly adsorbed by Cs@CA-CMC/Fe2O3-CuO beads, and the adsorption capacity of beads was 4.91 mgg−1, while 4.5 mgg−1 and 3.0 mgg−1 for Co(II) and Ni(II), respectively. Beads’ ability to adsorb Ag(I) varied depending on several factors. It was observed that the adsorption capacity of Ag(I) ions increased as the interaction time and metal concentration rose. However, increasing the beads dose led to a decrease in the Ag(I) ion adsorption. Further, the waste beads after Ag(I) adsorption were treated with reducing agent to form beads supported Ag nanoparticles (Ag/Cs@CA-CMC/Fe2O3-CuO) and used as effective catalyst for reducing 4-nitrophenol in the presence of NaBH4 as a reducing agent. Ag/Cs@CA-CMC/Fe2O3-CuO achieved reduction up to 93% for 4-NP within 30 min. The designed nanocomposite beads displayed several desirable attributes, including eco-friendliness and robust catalytic performance, making them highly promising for useful reduction of 4-NP.

Electrochemical detection of lead ions using carbon nanotube post electrodes

Heavy metal ions above their recommended limits are highly toxic to human health. Even at low levels, contaminants such as Pb in drinking water can severely affect vulnerable population of the society. Therefore, developing rapid, effective, stable, and convenient sensors for Pb detection has gained significant attention. In this study, considering the excellent properties of carbon nanotubes (CNTs), CNT post electrodes were fabricated by embedding them in a nonconducting polymer. The CNT posts were derived from a closely packed CNT forest with a diameter of 0.3 mm containing millions of vertically aligned pillars. The highly stable CNT post electrodes were employed for the electrochemical sensing of heavy metal ions in 0.1 M citric acid. A linear range of 9.64–168.7 nM (2–35 ppb) was observed for Pb ions. Further, linear ranges of 0.0786–7.86 μM (5–500 ppb) and 15.73–157.36 μM (1000–10000 ppb) were also obtained for Cu ions. Notably, the electrode containing a single CNT post was capable of the electrochemical detection of Pb ions at the ppb level. With this electrode, the sensitivity and limit of detection were 0.5095nA/nM and 2 nM (0.5 ppb) for Pb ions, and 24.53 μA/ppb and 41.67 nM (2.64 ppb) for Cu ions, respectively. The limit of detection for Pb ions is lower than the maximum permissible limit in drinking water set by the World Health Organization. Due the electrochemical method employed on its detection, the reported sensor can simultaneously detect Pb, Cu and Zn ions in tap water.

Investigation of extracellular polymeric substances (EPS) from cyanobacteria/blue green algae and their interaction with heavy metal ions: Insights from excitation-emission matrix fluorescence spectroscopy

Investigation of extracellular polymeric substances (EPS) from cyanobacteria/blue green algae and their interaction with heavy metal ions: Insights from excitation-emission matrix fluorescence spectroscopy

Genome wide analysis of HMA gene family in Hydrangea macrophylla and characterization of HmHMA2 in response to aluminum stress

Aluminum toxicity poses a significant threat to plant growth, especially in acidic soils. Heavy metal ATPases (HMAs) are crucial for transporting heavy metal ions across plant cell membranes, yet their role in Al3+ transport remains unexplored. This study identified eight HmHMA genes in the genome of Hydrangea macrophylla, categorizing them into two major clades based on phylogenetic relationships. These genes were found unevenly distributed across six chromosomes. Detailed analysis of their physicochemical properties, collinearity, and gene structure was conducted. RNA-seq and qRT-PCR analyses revealed that specific HmHMA genes, notably HmHMA2, were predominantly expressed in roots and flowers under Al3+ stress, indicating their potential role in Al3+ tolerance. HmHMA2 showed significant expression in roots, especially under Al3+ stress conditions, and when expressed in yeast cells, it conferred resistance to aluminum and zinc but increased sensitivity to cadmium. Overexpression of HmHMA2 in hydrangea leaf discs significantly improved Al3+ tolerance, reduced oxidative stress markers like hydrogen peroxide and malondialdehyde, and enhanced antioxidant enzyme activity such as SOD, POD and CAT compared to controls. These findings shed lights on the potential role of HmHMAs in Al transport and tolerance in H. macrophylla.

Dechlorination of Hexachlorobenzene by Ni/Fe Bimetallic Nanoparticles and the Influence of Co-Existing Heavy Metal Ions

Hexachlorobenzene (HCB) is one of the most persistent environmental pollutants of global concern. Ni/Fe nanoparticles, with their small particle size, large surface area, and high reactivity, are a promising candidate for HCB degradation. In this work, we investigated the kinetics and products of the dechlorination of HCB by Ni/Fe nanoparticles and how the presence of heavy metal ions Cd(Ⅱ) and Zn(Ⅱ) influences the reaction. It is found that 400 μg/L HCB can be rapidly removed by 7.5 g/L Ni/Fe nanoparticles and the removal percentage reaches 99% in 48 h. The removal is facilitated by adsorption and sequential dechlorination of HCB, producing PCB, 1,2,3,4-TeCB, and 1,2,3-TCB as the main products, with 1,2,3,5/1,2,4,5-TeCB, 1,2,4-TCB, and 1,2-DCB as the minor products. The addition of heavy metal ions Cd(Ⅱ) and Zn(Ⅱ) does not significantly affect the removal rate of HCB but hinders the adsorption and degradation of the byproducts through competitive adsorption. Additionally, the concentration of both Cd(Ⅱ) and Zn(Ⅱ) decreases rapidly and achieves over 98% removal in 4 h. Our study reveals that Ni/Fe nanoparticles can remove HCB and heavy metals Cd(Ⅱ) and Zn(Ⅱ) concurrently, with the extent of HCB dechlorination reduced compared to that without heavy metal. These findings may inform the application of Ni/Fe nanoparticles in the treatment of water bodies and soil contaminated by both halogenated aromatics and heavy metal.

Rapid and accurate identification of multiple metal ions using a bispyrene‐based fluorescent sensor array with aggregation‐induced enhanced emission property

AbstractMultiple metal ions are traditionally detected using inductively coupled plasma mass spectrometry (ICP‐MS) and atomic fluorescence spectrometry. Although these methods are sensitive and accurate, they depend on complex instruments and require highly trained operators, making low costly rapid detection challenging. It is urgent to develop a convenient, rapid and sensitive method to detect multiple metal ions. Herein, we designed a bispyrene derivative (BP) with aggregation‐induced enhanced emission (AIEE) property to construct a high fluorescent sensor array to realize the effective identification of four metal ions (Fe3+, Cu2+, Co2+ and Cd2+). The differential coordination capability between metal ions and BP with the aid of acetate ions resulted the possibility of array‐based sensing. The four heavy metal ions could be immediately classified in the concentration of 100 nM. The limit of detection (LOD) of Fe3+, Cu2+, Co2+, and Cd2+ were as low as 16.2, 21.8, 51.4, and 25.9 nM, respectively. Furthermore, the sensor array was applied for identification multiple heavy metal ions in environmental samples and iron ion in rat serums with identified of 100%. The sample consumption as low as 2 µL for each detection and the results could be extracted by smartphones under ultraviolet lamps. It provided a rapid, sensitive, low‐cost, and on‐site multiple metal ions detection method.

Interfacial Acid‐Like Microenvironment and Orbital Modulating Strategy toward Efficient Hydrogen Evolution in Neutral High‐Salinity Wastewater/Seawater

Electrochemical high‐salinity wastewater splitting is a promising technology for green hydrogen (H2) production. However, the kinetics of hydrogen evolution reaction (HER) in neutral media is slow, and the high theoretical potential of oxygen evolution reaction leads to large energy losses. Herein, an iron‐based electrocoagulation‐coupled hydrogen production integrated system (IEHPS) is constructed, which is realized by coupling low‐potential anodic iron oxidation reaction with cathodic HER. The non‐noble metal HxWO3‐Ni catalyst is synthesized by fabricating a proton sponge HxWO3 to achieve an interfacial acid‐like microenvironment and doping it with Ni heteroatom to modulate the 4d orbital of W, thereby weakening the adsorption strength of the W site toward hydrogen. Consequently, the HxWO3 Ni demonstrates remarkable performance characteristics, boasting a mere 131 mV overpotential at 10 mA cm−2 and Tafel slope of 44 mV dec− in neutral media. Operating at an applied voltage of 1.5 V, the IEHPS exhibits a high hydrogen production rate of 235 mL g−1 min−1 in seawater. It achieves nearly complete removal of contaminants like rhodamine B and heavy metal ions within a rapid 8–20 min, with an energy consumption of only 3.7 kWh Nm−3. This study provides a promising pathway for efficient and energy‐saving production of high‐purity hydrogen and effective treatment of high‐salinity wastewater.

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Dynamics of particle-particle correlations and the ridge effect in proton-proton collisions

In high-energy particle physics, the study of particle-particle correlations in proton-proton and heavy-ion collisions constitutes a pivotal frontier in the effort to understand the fundamental dynamics of the strong force. To the best of our knowledge, we employ for the first time the Balitsky-Fadin-Kuraev-Lipatov dynamics implemented in a Monte Carlo code in momentum space to compute final-state correlations in proton-proton collisions. Our present work aims to investigate whether the particular dynamics of the high-energy limit of QCD can contribute to the long-range rapidity correlations and the enigmatic ridge effect in proton-proton collisions. Published by the American Physical Society 2024

Radiation influence on planar reconfigurable field effect transistor low noise amplifier performance

Abstract Many novel devices have been proposed in the literature to mitigate the short channel effect and the reconfigurable FET (RFET) is one of them. The circuits based on new devices need to be investigated when they are introduced. This work has two parts: (i) designing cascoded RFET low noise amplifiers (LNA) and their performance analysis; and (ii) single-event performance analysis of RFET-LNAs. The designed LNA has a gain of 12 dB and a noise figure of 2.42 dB. The device in the common gate configuration mode is more susceptible to heavy ion radiation and collects more charge (QC) compared to the device in the common source configuration mode. Through temporal and frequency analysis, the irradiation disturbance is examined. In the temporal analysis, the collected charge (QC) is used as a metric, and the spectrogram is used in the frequency analysis.

Grad B Drifts of Heavy Ions Solar Energetic Particles at Solar Corona Region

The objective of this research study the Grad B drifts velocity of the heavy ion of the solar wind (C+4, C+5 (at corona region with distance (1 to 15) * 6.69*108m for two varied angles (Ɵ= 90ᵒ, 180ᵒ). It has been studied, that grad B drifts velocity, in the model of Parker spiral. within single particle dynamics model, in a spherical coordinate system (local coordinate system with an axis aligned with the magnetic field). This work result shown that, azimuthal grad B drift velocity, V∇Bφ` takes maximum value at polar zone for (C+4, C+5) for both velocities of solar wind. Also, there is no azimuthal grad B drifts V∇Bφ` at equators zone. And as for colatitude grad B drift velocity, V∇Bθ` takes high value at most of regions and the highest value at polar zone for fast and slow solar winds. And noting that the slow solar winds have higher values than fast solar wind at the equator region.

Nuclear suppression of coherent J/ψ photoproduction in heavy-ion ultraperipheral collisions and leading twist nuclear shadowing

We determine the nuclear suppression factor SPb(x), where x=MJ/ψ2/Wγp2 with MJ/ψ the J/ψ mass and Wγp the photon-nucleon energy, for the cross section of coherent J/ψ photoproduction in heavy-ion ultraperipheral collisions at the Large Hadron Collider and Relativistic Heavy Ion Collider by performing the χ2 fit to all available data on the cross section dσAA→J/ψAA/dy as a function of the J/ψ rapidity y and the photoproduction cross section σγA→J/ψA(Wγp) as a function of Wγp. We find that while the dσAA→J/ψAA/dy data alone constrain SPb(x) for x≥10−3, the combined dσAA→J/ψAA/dy and σγA→J/ψA(Wγp) data allow us to determine SPb(x) in the wide interval 10−5<x<0.05. In particular, the data favor SPb(x), which decreases with a decrease of x in the 10−4<x<0.01 interval and can be both decreasing or constant for x<10−4. Identifying SPb(x) with the ratio of the gluon distributions in Pb and the proton Rg(x,Q02)=gA(x,Q02)/[Agp(x,Q02)], we demonstrate that the leading twist approximation for nuclear shadowing provides a good description of all the data on dσAA→J/ψAA/dy and σγA→J/ψA(Wγp) as well as on the experimental values for SPb(x) derived from σγA→J/ψA(Wγp). We also show that modern nuclear parton distributions reasonably reproduce SPb(x) as well. Published by the American Physical Society 2024

The Influence of Particle Size and Calcium Content on Performance Characteristics of Metakaolin- and Fly-Ash-Based Geopolymer Gels.

This research systematically investigates the influence of raw material particle size and calcium content on the geopolymerization process to gain insight into the physical and mechanical properties of geopolymer gels, including setting time, fluidity, pore structure, compressive strength, and leaching characteristics of encapsulated Cr3+ heavy metal ions. Utilizing a diverse range of particle sizes of metakaolin (MK; 3.75, 7.5, and 12 µm) and fly ash (FA; 18, 45, and 75 µm), along with varied calcium levels, this study assesses the dual impact of these factors on the final properties of both metakaolin- and fly-ash-based geopolymers. Employing sophisticated analytical techniques such as Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Nuclear Magnetic Resonance (NMR), the research meticulously documents alterations in chemical bonding, micro-morphology, and pore structures. Key findings reveal that reducing the size of MK and FA particles to 3.75 and 18 µm, respectively, enhances the compressive strength of their matrices by 128.37 and 297.58%, respectively, compared to their original values (63.59 and 33.87 MPa, respectively) at larger particle sizes. While smaller particle sizes significantly bolster compressive strength, they adversely affect slurry flow and reduce the leaching rates of Cr3+ from MK- and FA-based matrices, reaching 0.42 and 0.75 mg/L at 3.75 and 18 µm, respectively. Conversely, increased calcium content markedly enhances setting times and contributes to the formation of dense microstructures through the production of calcium aluminate silicate hydrate (C-A-S-H) gels, thus improving the overall curing performance and durability of the materials. These insights underline the importance of fine-tuning particle size and calcium content to optimize geopolymer formulations, offering substantial benefits for varied engineering applications and promoting more sustainable construction practices.

Description of the emission of cumulative secondary particles in collisions of heavy ions of intermediate energies based on the non-equilibrium hydrodynamic approach

We have analyzed the double-differential cross sections for the emission of cumulative protons, pions, kaons, and antiprotons in collisions of carbon nuclei on a fixed target at an energy of 19.6 GeV/nucleon obtained in the IHEP experiment at the U-70 accelerator. When describing these spectra, the nonequilibrium approach was taken into account as a result of the joint solution of the kinetic equation with the equations of hydrodynamics. Comparisons with other approaches are made.

Concept study of a storage ring-based gravitational wave observatory: Gravitational wave strain and synchrotron radiation noise

This work for the first time addresses the feasibility of measuring millihertz gravitational waves (mHz GWs) with a storage ring-based detector. While this overall challenge consists of several partial problems, here we focus solely on quantifying design limitations imposed by the kinetic energy and radiated power of circulating ions at relativistic velocities. We propose an experiment based on the measurement of the time-of-flight signal of an ion chain. One of the dominant noise sources inherent to the measurement principle for such a GW detector is the shot noise of the emitted synchrotron radiation. We compute the noise amplitude of arrival time signals obtained by analytical estimates and simulations of ions with different masses and velocities circulating in a storage ring with the circumference of the Large Hadron Collider. Thereby, we show that our experiment design could reduce the noise amplitude due to the synchrotron radiation in the frequency range 10−4–10−2 Hz to one or two orders of magnitude below the expected GW signals from of astrophysical sources, such as supermassive binary black holes or extreme mass-ratio inspirals. Other key requirements for building a working storage ring-based GW detector include the generation and acceleration of heavy ion chains with the required energy resolution, their injection and continued storage, as well as the detection method to be used for the determination of the particle arrival time. However, these are not the focus of the work presented here, in which we instead concentrate on the definition of a working principle in terms of ion type, kinetic energy, and ring design, which will later serve as a starting point when addressing a more complete experimental setup. Published by the American Physical Society 2024

Analysis of transverse momentum spectra of protons, deuterons, and tritons in symmetric heavy-ion collisions at √(s_NN ) = 200 GeV at the RHIC

Abstract The blast wave model with Tsallis statistics is used to analyze the transverse momentum spectra of the protons (p), deuteron (d), and triton (t) in √(s_NN ) = 200 GeV gold-gold (Au-Au) collisions at RHIC in various centrality bins. In particular transverse momentum ranges, model results closely match experimental data from the PHENIX (p) and STAR (d and t) Collaborations. The data is compared with protons obtained in Cu+Cu collisions and deuteron and triton in Ru+Ru collisions at 200 GeV, center of mass energy from STAR collaboration. Particle spectra are used to derive the kinetic freeze-out temperatures, transverse flow velocities, and freeze-out volumes. According to the findings, the kinetic freeze-out temperature rises as one goes from the central to peripheral collisions. In this transition, the transverse flow velocity and the freeze-out volume both drop. In the collisions of both Collaborations, this work reveals mass-dependent kinetic freeze-out temperature and differential volume possibilities. On the whole, the non-extensivity parameter q decreases with increasing centrality of the studied heavy-ion collisions, and heavier mass particles have smaller values of q, which implies higher degrees of thermalization and equilibrium in more central collisions and for heavier particles.

Electrochemical/fluorescent dual-mode aptasensor based on 3D porous AuNPs/MXene for detection of ultra-trace mercury (Hg2+)

In this work, the dual-mode aptasensor based on 3D porous AuNPs/MXene using “turn-on” electrochemical method and “turn-off” fluorescent strategy was fabricated. Here, 2D MXene was processed into 3D porous MXene by sacrificial polymethylmethacrylate (PMMA) spherical template. And the meteor hammer-like AuNPs which had good electrochemical properties and quenching effect on fluorescence was synthesized by single electrodeposition. Dual-signal labeled Nile Blue (NB) was in situ grafted to the Hg2+ aptamer ends of 3D porous AuNPs/MXene/GCE, and an efficient and sensitive signal interface was constructed to realize the sensitive detection of Hg2+. 3D porous AuNPs/MXene had the advantages of large specific surface area, excellent electron transmission performance and signal amplification. The experimental results indicated that this sensor exhibited high sensitivity to Hg2+ in both electrochemical and fluorescent sensing, with detection limits of 2.69 fM and 1.60 fM, respectively. Further, the dual-mode aptasensor can ensure the detection accuracy and target quantization. The dual-mode aptasensor has been successfully applied to the ultra-trace detection of Hg2+ in actual water samples, which shows the potential of aptamer sensor in detecting heavy metal ions in environmental monitoring.

Impact of dicarboxystilbene impurities on the properties of swift heavy ion latent tracks in PET films

We present a new hypothesis and supporting experimental evidence about the essential role played by small impurities of dicarboxystilbene in the process of UV treatment of PET films irradiated with swift heavy ions (SHI). This treatment both forms highly selective membranes with permeability values comparable to natural ones (the track-UV technique) and sharply accelerates the etching of latent tracks in membrane production (the track-etching technique). We hypothesize (1) that these high permeability value is due to the presence of a molecular motor of an Archimedes screw type in the central part of the latent track formed by photoinduced trans-cis isomerization of dicarboxystilbene molecules that are anchored in helical conformations in the latent track; and (2) that the acceleration of etching rates is due to the preferential accumulation of phenanthrene-type molecules in the central part of the latent track due to the existence of a cyclization channel for photoexcited molecules of cis-dicarboxystilbene. In the presence of alkali solution, phenanthrene molecules release electrons which behave as strong anions in aqueous solution, catalyzing alkaline hydrolysis of PET molecules in the central part of the track. We present experimental observations of photoinduced changes in transmission light intensity after track-UV light treatment of both pristine and SHI irradiated PET films that confirm the presence of trans-cis isomerization of dicarboxystilbene molecules and show their contribution to the formation of new helical conformations in SHI irradiated PET films during the light treatment.