Search

The design and construction of a high-voltage power supply for an electrostatic accelerator have been carried out at the Nuclear Science and Technology Research Institute in Iran. This power supply is capable of accelerating hydrogen ion beams in both single-stage and tandem modes. Ongoing collaboration with Shahid Beheshti University is focused on the accelerator's design. Tandem electrostatic accelerators achieve high energy resolution by utilizing the high-voltage power supply twice: first to accelerate generated H⁻ ions, and then to accelerate H⁺ ions after a charge exchange that occurs in the middle section. This article presents the optimization of a gaseous charge exchange cell for a tandem accelerator with a high-voltage range of 0.3–1.7 MV. The study employs numerical methods that couple the evaluation of pressure profile on hydrogen beam path, with the charge exchange processes in the cell by the transport of ion beams through it. For this purpose, COMSOL Multiphysics software was used as a tool. The Free Molecular Flow interface of COMSOL Multiphysics software was used for calculation of pressure profile in the accelerating tubes and charge exchange section while nitrogen gas throughput was injected and vacuum pumps are running. The optimal dimensions of the charge exchange cell were determined while maintaining a vacuum level in the accelerating tubes of 10−8 to 10−7 mbar. At least, the pressure profile in the beam path as a result of calculations by Free Molecular Flow interface was coupled to Charged Particle Tracing interface in COMSOL Multiphysics software as an input. Then the charge exchange efficiency was calculated for different nitrogen gas throughputs. The final results show that a conversion efficiency of 99.1% at 0.3 MeV and 99.9% at 1.7 MeV for H⁻ to H⁺ ion beam conversion. This was accomplished by nitrogen gas throughput at rates between 7 and 25 Standard Cubic Centimeters per Minute (SCCM). • Study employs numerical methods to evaluate pressure profiles and charge exchange. • Pressure profile from Free Molecular Flow was input for Charged Particle Tracing. • Optimal dimensions maintain a vacuum level of 10⁻⁸ to 10⁻⁷ mbar. • Charge exchange efficiency for H− to H+ was 99.1% at 0.3 MeV and 99.9% at 1.7 MeV. [ABSTRACT FROM AUTHOR]

Soft pumps have the potential to transform industries including soft robotics, wearable devices, microfluidics and biomedical devices, but their efficiency and power supply limitations hinder prolonged operation. Here, we report a self-powered triboelectric-electrohydrodynamic pump, which combines a soft electrohydrodynamic pump driven by an electrostatic generator, specifically a triboelectric nanogenerator. The triboelectric nanogenerator collects ambient energy and converts it into high-voltage power source, allowing it to self-power an electrohydrodynamic pump and thus eliminating the need for external power supply. Using power management circuit, geometric shape optimization, and stacking methods, we achieve a maximum pressure of 4.49 kPa and a maximum flow rate of 502 mL/min. We demonstrate the pump's versatility in applications such as self-powered soft actuators, oil pumping in microfluidics, and oil purification. The triboelectric-electrohydrodynamic pump holds promising applications, and offers new insights for the development of fully self-powered systems. Soft pumps have applications across various fields but are constrained by their dependence on external power sources. Here, the authors present a battery-free electrohydrodynamic soft pump that utilizes a triboelectric nanogenerator to harvest ambient energy, serving as the driving source for dielectric fluid flow. [ABSTRACT FROM AUTHOR]

A new design of a flexible and compact electrostatic generator with dielectric fluid is presented in this work. The generator utilizes the flow of dielectric fluid between two dielectric films to change the capacitance and converts mechanical energy into electrical energy. We fabricate a dielectric fluid generator (DFG) and build up an experimental setup to investigate the performance of energy harvesting. We use an optimal triangular electromechanical cycle and achieve a maximum energy harvesting power of 1.83 mW with a device that the length of the longest side is 15 cm. The power density is 35.2 μW g−1, and the conversion efficiency is 17.8%. The parameters of the DFG, including the initial voltage, the applied force, and the mechanical loading time, are studied. As a demonstration, we use the DFG to harvest electrical energy from hand tapping to power LEDs. The DFG is flexible and compact, which is promising for harvesting energy from human movements. [ABSTRACT FROM AUTHOR]

Addressing the issues of inefficiency and severe environmental pollution associated with artificial and chemical methods in cotton growth regulation, this study introduces the high-voltage electrostatic field environmental control technology. It delves into the technology's macro- and microscopic impacts on cotton seedling growth and optimizes its operational parameters. At the macro level, the study examines the influence of adjusting the output voltage of the high-voltage electrostatic generator, the distance between the upper pole plate and the cotton leaf, and the action time of the electric field on seedling features above (plant height, ground diameter, and leaf area) and below ground (fresh weight and dry weight of roots). Subsequently, utilizing an orthogonal experimental design, the optimal parameters are identified: output voltage of 15.93 kV, a distance of 10.71 cm between the pole plate and cotton leaf, and an action time of 39.23 s, resulting in the most favorable overall growth condition. At the micro level, conductivity meters and transmission electron microscopy techniques are employed to investigate leaf electrical conductivity and ultrastructure changes under a high-voltage electrostatic field. Results indicate a slight conductivity increase under moderate conditions (e.g., 18 kV-8 cm), signifying healthy cell membranes. Conversely, extreme conditions (e.g., 18 kV-2 cm or 36 kV-8 cm) cause marked conductivity spikes, pointing to cellular damage. Transmission electron microscopy observations reinforce this, with intact membranes under optimal conditions but disintegration and degradation under adverse ones. In conclusion, this study unravels the internal mechanisms of high-voltage electrostatic field regulation on cotton seedling growth from macro- to micro-scales, validating its feasibility and effectiveness. This breakthrough not only pioneers a novel approach for cash crop seedling growth control but also lays a scientific foundation for refining and advancing cotton cultivation techniques, thereby advancing agricultural modernization and sustainable development goals. [ABSTRACT FROM AUTHOR]

CR-39 proton radiography is an experimental charged-particle backlighter platform fielded and used at OMEGA and the NIF to image electric and magnetic fields in a subject plasma. Processing a piece of CR-39 involves etching it in hot NaOH, and the etch time can greatly impact the background-to-signal ratio (BSR) in low-fluence (≲4 × 104 cm−2) regions and detection efficiency in high-fluence regions (≳7 × 105 cm−2). For CR-39 data with high fluence variation, these effects mean that any single etch time will result in ≳15% error in the measured signal in either the high- or low-fluence regions. This study aims to quantify the impact of the etch time on the BSR and efficiency losses and how these affect the field reconstruction. Experiments at the MIT Linear Electrostatic Ion Accelerator provided empirical values of the BSR and efficiency losses as a function of the fluence and etch time for fluences ranging from 3 × 103 to 7 × 105 cm−2. Synthetic radiographs were generated with known fields and modulated based on empirical values of BSR and efficiency losses. The fields were reconstructed using a Monge–Ampère code with the modulated radiographs as input. The results indicate that combining short and long etches allows for more accurate analysis of radiographs with high fluence variation, with the mean squared error of the reconstructed fields decreasing by factors of 1.2–7 compared to the reconstructions using only one etch time. [ABSTRACT FROM AUTHOR]

The activation level of the JAEA-Tokai tandem accelerator facility was investigated experimentally in advance of the future decommissioning. JAEA-Tokai tandem accelerator facility has a higher terminal voltage of 18 MV and a larger total floor area, Compared to other electrostatic accelerators with terminal voltage of 1 MV to 6 MV. Therefore, determination for 'where,' 'what,' and 'how many' nuclides are produced in the facility is crucial. Thermal neutrons generated by beam losses associated with accelerator operations contribute significantly to the activation of equipment and facilities. The accumulated activities of60Co and152Eu; the most considerable radionuclides at the decommissioning, can be deduced by the thermal neutron fluence rate during the accelerator operation. In this study, thermal neutron fluence measurement on the surface of the pressure vessel and concrete building was conducted with conventional methods using dosimeters and metal foil detectors as well as a new method using a portable γ-ray detector. The thermal neutron fluence in the facility during the accelerator operation ranges from 101 to 104 n/cm2/s. The sum of deduced activities of60Co and152Eu in 50 years is much lower than the clearance level of 0.1 Bq/g in all areas except in the irradiation room. [ABSTRACT FROM AUTHOR]

Image plates (IPs) are a quickly recoverable and reusable radiation detector often used to measure proton and x-ray fluence in laser-driven experiments. Recently, IPs have been used in a proton radiography detector stack on the OMEGA laser, a diagnostic historically implemented with CR-39, or radiochromic film. The IPs used in this and other diagnostics detect charged particles, neutrons, and x-rays indiscriminately. IPs detect radiation using a photo-stimulated luminescence (PSL) material, often phosphor, in which electrons are excited to metastable states by ionizing radiation. Protons at MeV energies deposit energy deeper into the IP compared with x rays below ∼20 keV due to the Bragg peak present for protons. This property is exploited to discriminate between radiation types. Doses of mono-energetic protons between 1.7 and 14 MeV are applied to IPs using the MIT linear electrostatic ion accelerator. This paper presents the results from consecutive scans of IPs irradiated with different proton energies. The PSL ratios between subsequent scans are shown to depend on proton energy, with higher energy protons having lower PSL ratios for each scan. This finding is separate from the known energy dependence in the absolute sensitivity of IPs. The results can be compared to complimentary work on x rays, showing a difference between protons and x rays, forging a path to discriminate between proton and x-ray fluence in mixed radiation environments. [ABSTRACT FROM AUTHOR]

Layered materials incorporating hydrogen were obtained using Nb/Zr films with varying numbers of layers from 50 to 100. The films were deposited on a silicon substrate using a vacuum magnetron sputtering method on a dedicated setup. The film thickness varied from 10 to 50 nm. The resulting material was hydrogenated with protons on a TPU electrostatic generator with an energy of up to 1.2 MeV. The deposition modes for nanoscale metallic multilayer Zr/Nb systems were determined: for a Zr target the specific power of the sputtering system was 37.9 W/cm2, and for a Nb target it was 26.4 W/cm2. A coating with clear boundaries between individual layers of zirconium and niobium was obtained. It was shown that the optimal conditions for studying nanoscale Zr/Nb layers are a pressure of 700 Pa, a power of 40 W, a frequency of 2 kHz, and a plasma filling factor of 12.5% for coatings with individual layer thicknesses of 100 nm. For coatings with layer thicknesses from 10 to 50 nm, the optimal conditions are a pressure of 650 Pa, a power of 40 W, and a frequency of 1 kHz. The thermo EMF method (GOST (State Standard) 25315–82) was used for testing. It was found out that after proton irradiation, an intensive accumulation of hydrogen atoms occurs near the interfaces; it reduces the structure defectiveness and entails a change in the thermo EMF up to the inversion of its sign. The hydrogen distribution is predominantly bimodal, with local maxima in hydrogen concentration observed at the Nb/Zr interfaces, while accumulation at the Zr/Nb interface is considerably lower. Hydrogen localization near interfaces primarily occurs around zirconium. [ABSTRACT FROM AUTHOR]

The scanning nuclear microprobe of the Institute of Applied Physics of the National Academy of Sciences of Ukraine is an analytical channel based on the compact electrostatic accelerator “Sokol” of the Van de Graaff type with the maximum voltage at the high-voltage terminal of 2 MV and is designed for local non-destructive analysis of samples of various origins with high sensitivity (~1 ppm), as well as for the fabrication of three-dimensional small structures of high quality using proton beam writing. The resolution of the microprobe is about 3 μm with a beam current of I ~ 100 pA and 0.6 μm with I ~1 pA. The maximum scanning raster with a focused beam on the sample surface is 1 × 1 mm² . The microprobe implements the techniques of particle-induced X-ray emission, Rutherford backscattering, and secondary electron microscopy. The article also gives examples of the use of the nuclear microprobe in physical research. [ABSTRACT FROM AUTHOR]

In this study, the target molecule ethyl-2-(5-nitro-5'-(4-nitrophenyl)-2-oxo-3'H-spiro[indoline-3,2'-[1,3,4]oxadiazol]-1-yl)acetate, which is a spiroindoline derivative, were performed NBO analysis, molecular electrostatic potential surface (MEPS), nonlinear optics (NLO), HOMO-LUMO energy calculations, optimized molecular geometry, and mulliken atomic charges using B3LYP/B3PW91 basis set and 6-311G(d,p) approximations. Calculated results were reported. Density Functional Theory (DFT) computations were utilized to research the molecule theoretically. Moreover, molecular docking analysis of the tested compound, a spiroindoline derivative molecule targeting aldose reductase against diabetic complications, was performed using molecular docking to determine the structure- activity connection. The molecular docking scores of our study molecule showed good results of -6.83 (PDB ID:3ABV) and 6.78 (PDB ID:3AE2) kcal. The molecular docking study provided important information worth considering for further research. A notable outcome of bioisosteric and isosteric substitutions is the alteration in lipophilic character, an impressive characteristic in several aspects. Thus, utilizing SwissADME, lipophilic character assessments were performed for the concerned compounds. [ABSTRACT FROM AUTHOR]

Electrostatic generators show great potential for powering widely distributed electronic devices in Internet of Things (IoT) applications. However, a critical issue limiting such generators is their high impedance mismatch when coupled to electronics, which results in very low energy utilization efficiency. Here, we present a high-performance energy management unit (EMU) based on a spark-switch tube and a buck converter with an RF inductor. By optimizing the elements and parameters of the EMU, a maximum direct current output power of 79.2 mW m-2 rps-1 was reached for a rotary electret generator with the EMU, achieving 1.2 times greater power output than without the EMU. Furthermore, the maximum power of the contact-separated triboelectric nanogenerator with an EMU is 1.5 times that without the EMU. This excellent performance is attributed to the various optimizations, including utilizing an ultralow-loss spark-switch tube with a proper breakdown voltage, adding a matched input capacitor to enhance available charge, and incorporating an RF inductor to facilitate the high-speed energy transfer process. Based on this extremely efficient EMU, a compact self-powered wireless temperature sensor node was demonstrated to acquire and transmit data every 3.5 s under a slight wind speed of 0.5 m/s. This work greatly promotes the utilization of electrostatic nanogenerators in practical applications, particularly in IoT nodes. [ABSTRACT FROM AUTHOR]

In order to obtain a potential difference of tens of thousands of volts, electrostatic generators can be used. In this work, we describe how to make a simple electrostatic generator, whose working principle is based on electrification by friction. Moreover, we also describe how to estimate the expected values for both the produced voltage and the generated electric current by this generator. [ABSTRACT FROM AUTHOR]

"Data-centric infrastructure" is an information and communication technology infrastructure for highly efficient processing of data scattered over a wide area, and in a data-driven society, it is expected to be used as the foundation of large-scale cyber-physical systems (CPSs). The concept of a data-centric infrastructure, which effectively uses accelerators and the All-Photonics Network to provide a dataprocessing pipeline, is outlined in this article. A step-by-step demonstration of the concept is introduced by using video analysis as a use case concerning a CPS. [ABSTRACT FROM AUTHOR]

Observations of a quiet electrostatic auroral arc by the ALIS network on 5 March 2008 are used to infer a two‐dimensional map of the flux of precipitating energy. Among a family of numerical solutions of a stationary magnetosphere—ionosphere coupling model in which the origin of the arc is a magnetospheric generator interface, we find which generator interface properties best fit the observed precipitating energy flux. The procedure finds that the plasma populations in the generator are colder and more rarefied on one side of the interface and warmer and denser on the other side, similar to a transition between plasma trough and plasma sheet plasmas. The increase of the arc's brightness, the decrease of its thickness and its slight spatial undulation may be driven by an increase of plasma sheet electron temperature in the tailward direction, tangential to the interface, and a local spatial indentation in the dawn‐ward direction. Plain Language Summary: Optical observations of aurora provide information about the local electromagnetic and plasma conditions in the ionosphere where the impact of energetic electrons produces auroral light emissions. The electrons gain energy through acceleration by static or dynamic electric fields along their path from the magnetospheric source to the upper ionized atmosphere where they collide with various atomic species, like oxygen and nitrogen, which emit light at various wavelengths. In this paper we use optical observations of a steady electrostatic auroral arc to identify the conditions in the magnetospheric source that best fit these observations in the context of an electrostatic auroral acceleration model. This way, optical auroral observations from the ground are used as a remote sensing tool to probe the magnetospheric source of the arc. Key Points: A new application using tomographic imaging of electrostatic auroral arcs with ALIS estimates the magnetospheric generator stateThe generator of the arc observed by ALIS appears to be a plasma interface at the contact between trough and plasma sheet‐like plasmasThe arc's longitudinal changes are linked to a tailward increase of electron temperature and dawnward indentation of the generator interface [ABSTRACT FROM AUTHOR]

Recently, progress in technology for accelerator-based neutron sources has increased attention regarding boron neutron capture therapy (BNCT). BNCT is a type of radiotherapy that combines neutrons and boron drugs and is expected to be used in the treatment of refractory and recurrent cancers. Owing to the need for high-intensity neutrons in treatment, compact accelerator-based neutron sources applicable to BNCT are being developed worldwide. These current projects utilize cyclotrons, linear accelerators, and electrostatic accelerators as accelerators for BNCT devices. Beryllium and lithium are the main target materials for neutron generation. The accelerators for BNCT device are required to accelerate charged particles with an average current ranging from a few milliamperes to a few tens of milliamperes in order to generate neutrons of sufficient intensity for the treatment. Moreover, the target systems require technologies and mechanisms that can withstand the large heat load produced by high-power beam irradiation and prevent blistering. This review outlines and explains the accelerator neutron sources for BNCT and the requirements for the components of each device, such as the accelerator, target material, and beam shaping assembly. In addition, various development projects for accelerator-based BNCT devices worldwide are introduced. [ABSTRACT FROM AUTHOR]

Electrostatic discharge (ESD) is a physical phenomenon that may destroy electronic components due to its high discharge current that may reach a few amperes in just a few ns. However, another major aspect of ESD is the related high-frequency electromagnetic (E/M) fields radiated by the ESD event. The electronic equipment that is affected by the ESD phenomenon is additionally affected by the induced voltages caused by these E/M fields. This is the reason that the current version of the IEC 61000-4-2 on ESD has a special reference to these fields and the measurement setup. Starting with the classical formulation of these fields, this paper reviews the most popular techniques for calculating the ESD electromagnetic fields while also emphasizing the best methods for minimizing computational effort. There is also a separate section for the measurement techniques that have been applied in research works, whose outcomes could be implemented in the next revision of the IEC 61000-4-2. It is extremely important for the next revision to include these measurement setups and the E/M field sensors because the ESD generators should comply with certain values related to the E/M fields they produce. [ABSTRACT FROM AUTHOR]

The boron neutron capture therapy (BNCT) system developed by the Korea Institute of Radiological and Medical Sciences is a compact neutron source that can be installed at medical institutes. The target energy was accelerated to a maximum of 2.4 MeV–20 mA by introducing a gas stripping device that converts negative hydrogen ions into positive ions. By using the tandem-type accelerator in this way, a high-voltage DC power supply was designed with 1.2 MV–45 mA as the maximum capability. The design was improved to reduce the number of stages of a Cockcroft–Walton voltage multiplier. Hence, the ripple risk of the DC flat top resulting from unwanted stray capacitance was lowered. The overall height and volume of the Cockcroft–Walton voltage multiplier were reduced to less than half those of the existing design method, making miniaturization possible. After such advanced design and manufacturing, performance tests were performed at 750 kV–45 mA under 23 stages of the Cockcroft–Walton voltage multiplier, which is the highest level that can perform at its maximum under in-air conditions. It demonstrated stable performance under in-air conditions without breakdown for 2 h, even at 620 kV–35 mA. To reach the final target of 1.2 MV–45 mA, the groundwork is laid for achieving experimental performance while satisfying the optimal requirements in SF6 gas. [ABSTRACT FROM AUTHOR]

Electrostatic electret generator has attracted a lot of attention in recent years, but their low power density cannot be ignored. Based on the existing research, this paper increases its power density from two aspects, including in-plane and in-space aspects. In the plane aspect, through simulation analysis, we can draw a conclusion that the output power can be increased effectively by using the bipolar charging method. From the perspective of space, the power density can be increased several times by connecting the output ends of the multi-layer generation structure. By integrating the method into the electrostatic electret generator, the power output can be effectively increased, which is suitable to the application of higher energy requirements in the specific field and a certain application prospect. [ABSTRACT FROM AUTHOR]

Calculating meteoroid masses from photometric observations relies on prior knowledge of the luminous efficiency, a parameter that is not well characterized; reported values vary by several orders of magnitude. We present results from an experimental campaign to determine the luminous efficiency as a function of mass, velocity, and composition. Using a linear electrostatic dust accelerator, iron and aluminum microparticles were accelerated to v > 10 km/s and ablated, and the light production measured. The luminous efficiency of each event was calculated and functional forms fit for each species. For both materials, the luminous efficiency is lowest at low velocities, rises sharply, then falls as velocity increases. However, the exact shape and magnitude of the curve is not consistent between the materials. The difference between the luminous efficiencies for iron and aluminum, particularly at high velocities, indicates that it is not sufficient to use the same luminous efficiency for all compositions and velocities. Plain Language Summary: Material left behind by meteoroids and interplanetary dust particles entering Earth's atmosphere are important drivers of atmospheric phenomena and chemistry. There is large spread in estimates of the total meteoric mass input, in part due to uncertainty in several key parameters that are required to make mass estimates of individual particles. This work presents an experimental campaign to characterize one such parameter, the luminous efficiency, in a laboratory setting. The luminous efficiency describes the amount of a meteoroid's kinetic energy that is converted into light energy; large uncertainty in historical measurements of the luminous efficiency directly correspond to large uncertainties in mass estimates made from optical observations. The results show that there is significant variation in the luminous efficiency as a function of both particle velocity and composition, indicating that relying on a single value for the luminous efficiency is not sufficient in all cases. Key Points: Improved laboratory ablation experiments characterize luminous efficiencies of iron and aluminum at velocities greater than 10 km/sEmpirical curve fits are derived to relate the luminous efficiency and particle velocity for both speciesDifferences in iron and aluminum results indicate that the luminous efficiency varies with composition [ABSTRACT FROM AUTHOR]

In this paper, we describe the upgrade of a small electrostatic dust accelerator located at the University of Stuttgart. The newly developed dust source, focusing lens, differential detector and linac stage were successfully installed and tested in the beam line. The input voltage range of the dust source was extended from 0–20 kV to 0–30 kV. A newly developed dust detector with two differential charge sensitive amplifiers is employed to monitor particles with speeds from several m/s to several km/s and with surface charges above 0.028 fC. The post-stage linac provides an additional acceleration ability with a total voltage of up to 120 kV. The entire system of this dust accelerator works without protection gas and without a complex high voltage terminal. The volumes to be pumped down are small and can be quickly evacuated. The new system was used to accelerate micron- and submicron-sized metal particles or coated mineral materials. Improvements in the acceleration system allow for a wider variety of dust materials and new applications. [ABSTRACT FROM AUTHOR]

Due to the severe impacts of climatic change, many recent developments in air cleaning systems have received an increasing attention. The best solution for expelling pollutant particles, met in industrial and commercial applications, is the electrostatic precipitator (ESP). One of the key components in the ESP system is the high-voltage power supply. Many recent studies have proven that the sectionalization of industrial ESPs enhances their particle collection efficiency. Consequently, this paper proposes a new modular switched-capacitor voltage multiplier-based multi-module high-voltage pulse power supply. In the proposed configuration, the two different patterns of output pulse are adopted. The proposed scheme is characterized by its modular structure and its capability of providing two isolated high-voltage pulse generators for each two ESP bus sections from one low-voltage AC source with an adjustable repetition rate, a controllable pulse width, and the desired values of the base and pulse voltages. A detailed illustration and simulation results are presented for the proposed approach. A comparative study is presented to elucidate the advantages of the proposed topology in contrast with the existing topologies. Finally, a - 1.2 -kV, 0.36 -kW experimental setup has been built to show the viability of the proposed concept. [ABSTRACT FROM AUTHOR]

Development of an electrostatic induction generator began in 2009. Since it was known that the electrostatic induction mechanism had the advantage of being highly resistant to magnetic fields, the development of a motor was also initiated in 2015. As a result, Cal.NS30 movement, equipped with an electrostatic induction generator/motor, was developed. ACCUTRON SPACEVIEW 2020, equipped with this movement, was launched to commemorate the 60th anniversary of the release of the “ACCUTRON”. The technical outline of the Cal.NS30 movement is reported as below. [ABSTRACT FROM AUTHOR]

Charged defects are often studied within the periodic density functional theory (DFT), but this introduces strong finite-size artifacts. In this work, we develop an electrostatic image interaction correction (IIC) method based on the direct solution of the Poisson equation for charge models constructed directly from DFT calculations. These IICs are found to be detail-insensitive, depending almost entirely on bulk dielectric properties. As these IICs are not able to fully explain the observed finite-size scaling, we explore potential alignment in detail and introduce a novel decomposition to separate out different contributions. We find that the two main sources of potential alignment are defect image interactions and changes in the number of atoms present in the supercell. This first effect is accurately predicted by the periodic part of our IIC. The second contribution is unrelated to the IIC and justifies the common observation that the magnitude of finite-size dependence can strongly vary between vacancy and interstitial defects. It can be approximately predicted using atomic radius, but is strongly sensitive to the pseudopotential employed. Combined, these developments provide a new justification for known finite-size scaling rules. Our results suggest that for cubic supercells, the Lany-Zunger IIC, combined with simplified potential alignment between neutral systems, can yield accurate corrections in spite of the simplicity of the approach. [ABSTRACT FROM AUTHOR]

Powdery mildew fungi produce progeny conidia on conidiophores, and promote the spread of powdery mildew diseases by dispersal of the conidia from conidiophores in the natural environment. To gain insights and devise strategies for preventing the spread of powdery mildew infection, it is important to clarify the ecological mechanism of conidial dispersal from conidiophores. In this study, all of the progeny conidia released from single colonies of strawberry powdery mildew fungus (Podosphaera aphanis (Wallroth) U. Braun and S. Takamatsu var. aphanis KSP-7N) on true leaves of living strawberry plants (Fragaria × ananassa Duchesne ex Rozier cv. Sagahonoka) were consecutively collected over the lifetime of the colony with an electrostatic rotational spore collector (insulator drum) under greenhouse conditions, and counted under a high-fidelity digital microscope. The insulator drum consisted of a round plastic container, copper film, thin and transparent collector film, electrostatic voltage generator, and timer mechanism. When negative charge was supplied from the voltage generator to the copper film, the collector film created an attractive force to trap conidia. The electrostatically activated collector film successfully attracted progeny conidia released from the colony. Experiment was carried out at just one colony on one leaf for each month (in February, May, July, October, November, and December in 2021), respectively. Each collector film was exchanged for a new collector film at 24 h intervals until KSP-7N ceased to release progeny conidia from single colonies. Collection experiments were carried out to estimate the total number of conidia released from a single KSP-7N colony over a 35–45-day period after inoculation. During the fungal lifetime, KSP-7N released an average of 6.7 × 104 conidia from each of the single colonies at approximately 816 h. In addition, conidial release from KSP-7N colonies was largely affected by the light intensity and day length throughout a year; the number of conidia released from single KSP-7N colonies in night-time was clearly smaller than that in daytime, and the time of conidial release from single KSP-7N colonies was shorter by approximately 2 to 4 h in autumn and winter than in spring and summer. The ecological characteristics related to conidial releases from KSP-7N colonies will be helpful information for us to successfully suppress the spread of strawberry powdery mildews onto host plants under greenhouse conditions. [ABSTRACT FROM AUTHOR]

This paper presents a diagnostic method for THz pulses produced by EA-FEL. Experimental results present a comparison between ZnTe and GaAs crystals for the detection of a single terahertz pulse using electro-optic sampling. In order to match an electro-optic detector for the EA-FEL radiation, the THz pulse from a source was simultaneously detected by ZnTe and GaAs electro-optic detectors. The GaAs detection system was found to have a shorter response time but low signal-to-noise ratio (SNR) compared to the ZnTe system. The GaAs crystal is suitable for the detection of short THz pulses due to fiber coupling, and the SNR of the GaAs system can be improved using a faster and more sensitive photodetector. [ABSTRACT FROM AUTHOR]

Energy harvesters serve as continuous and long-lasting sources of energy that can be integrated into wearable and implantable sensors and biomedical devices. This review paper presents the current progress, the challenges, the advantages, the disadvantages and the future trends of energy harvesters which can harvest energy from various sources from the human body. The most used types of energy are chemical; thermal and biomechanical and each group is represented by several nano-generators. Chemical energy can be harvested with a help of microbial and enzymatic biofuel cells, thermal energy is collected via thermal and pyroelectric nano-generators, biomechanical energy can be scavenged with piezoelectric and triboelectric materials, electromagnetic and electrostatic generators and photovoltaic effect allows scavenging of light energy. Their operating principles, power ratings, features, materials, and designs are presented. There are different ways of extracting the maximum energy and current trends and approaches in nanogenerator designs are discussed. The ever-growing interest in this field is linked to a larger role of wearable electronics in the future. Possible directions of future development are outlined; and practical biomedical applications of energy harvesters for glucose sensors, oximeters and pacemakers are presented. Based on the increasingly accumulated literature, there are continuous promising improvements which are anticipated to lead to portable and implantable devices without the requirement for batteries. [ABSTRACT FROM AUTHOR]

The 10 MV FN Tandem at the University of Notre Dame's Nuclear Science Laboratory has the option for a second foil stripper halfway down its high energy column. With its utilization, users are able to produce beams with higher energies and/or transmission than single foil stripping alone would be capable of achieving. A discussion of the Schiwietz–Grande, Nikolaev–Dmitriev, and Baudinet-Robinet semi-empirical models used to determine the resulting charge state abundances, as well as how they compare to measured charge state distributions is presented. The advantages of a second foil stripper are discussed alongside measurements of the charge state abundances produced. The potential for more interfering beam species of similar magnetic rigidity is also discussed. It was found that for most of the beams tested, second foil stripping allowed higher energies with higher yields than the single terminal foil stripping alone could achieve which can enhance the capabilities of other laboratories using similar accelerator systems. [ABSTRACT FROM AUTHOR]

In order to improve the deposition and uniformity of the pesticide sprayed by the agricultural spraying drone, this study designed a novel spraying system, combining air-assisted spraying system with electrostatic technology. First, an air-assisted electrostatic centrifugal spray system was designed for agricultural spraying drone, including a shell, a diversion shell, and an electrostatic ring. Then, experiments were conducted to optimize the setting of the main parameters that affect the charge-to-mass ratio, and outdoor spraying experiments were carried out on the spraying effect of the air-assisted electrostatic centrifugal spray system. The results showed the optimum parameters were that the centrifugal rotation speed was 10 000 r/min, the spray pressure was 0.3 MPa, the fan rotation speed was 14 000 r/min, and the electrostatic generator voltage was 9 kV; The optimum charge-to-mass ratio of the spray system was 2.59 mC/kg. The average deposition density of droplets on the collecting platform was 366.1 particles/cm2 on the upper layer, 345.1 particles/cm2 on the middle layer, and 322.5 particles/cm2 on the lower layer. Compared to the results of uncharged droplets on the upper, middle, and lower layers, the average deposition density was increased by 34.9%, 30.4%, and 30.2%, respectively, and the uniformity of the distribution of the droplets at different collection points was better. [ABSTRACT FROM AUTHOR]

Two main insulating gases of SF6 and N2/CO2 mixture are employed to increase voltage capability of electrostatic accelerators. SF6 offers more insulating capability, but environmental and technical disadvantages of SF6 makes usage of N2/CO2 mixture a desirable option. This paper aims to replace SF6 with N2/CO2 in design of a 500 kV/30 mA parallel-fed voltage multiplier. High-voltage section of the accelerator is a capacitive structure which in combination with rectifying elements, generates the accelerating high-voltage. The structure which is called Voltage Multiplier Capacitive Structure (VMCS) is designed and analyzed in this paper. The first structure is designed to employ SF6 as insulating gas (VMCS500). Then, the structure is modified to be capable of using N2/CO2 as insulating gas with lower breakdown voltage (VMCS500-m). The modified structure requires more complex mechanical manufacturing process, but offers the simplicity of using N2/CO2 mixture, the option of using the modified structure with superior SF6 gas, increasing the output voltage and beam energy. CST EM STUDIO was used for capacitance calculation and electric field analysis. LTSPICE was used for equivalent circuit analysis of the high voltage generating section. [ABSTRACT FROM AUTHOR]

To build a proton beam accelerator that can be applied to a boron neutron capture therapy system based on an electrostatic accelerator, a high-voltage direct-current (DC) power supply system equivalent to the generation of neutrons should be provided. The symmetrical Cockcroft–Walton voltage multiplier method is suitable for stable acceleration of the proton beam in the tandem electrostatic accelerator in this system. Before the second step-up with the Cockcroft–Walton circuit, the design of the inverter is prioritized by preponderantly considering the first voltage and resonance frequency. Moreover, the optimized stacking number is determined with consideration of the ripple voltage, voltage drop, average output voltage, and fundamental harmonics, and a design is performed to set related parameter values to be stable in the flat-top region of the voltage. A high-voltage DC power supply system of 1.2 MV/45 mA is needed for a stable terminal energy of 2.4 MeV/20 mA. Such a design can be optimized by securing reliable data using a simulation tool on the basis of theoretical calculations. This will become a formidable touchstone in manufacturing technology based on acquiring practical know-how for setting up a tandem electrostatic accelerator-based boron neutron capture therapy system in the future. [ABSTRACT FROM AUTHOR]

The armature is an important part affecting the energy conversion efficiency of a reluctance accelerator. In this paper, six kinds of soft magnetic materials are chosen and four structures are designed for the armature. At first, the circuit and magnetic force are theoretically analyzed. Then the armatures with different materials and structures are used in the simulation, and the performances are compared and analyzed. At last, the experiment verifies the theory analysis and simulation design. It is concluded that the saturation flux density and conductivity of the material are the key factors affecting the armature force, and the optimization of armature structure can effectively restrain the eddy current, reduce negative force and improve efficiency. Compared with cutting slits in solid armatures, laminating the sheets radially can reduce the eddy current more efficiently. Although slitting can prevent the eddy current to a certain extent, meanwhile, it will decrease the magnetic force because of the losing of magnetized volume and the surface area. Hence, choosing the high saturation flux density material and making out the armature with radially_laminated sheets will improve the efficiency of the reluctance accelerator. In this paper, the silicon steel radially_laminated armature is a better choice for the armature design of the reluctance accelerator. [ABSTRACT FROM AUTHOR]

Many variable-capacitance energy harvesters employ a large inductor to improve their power efficiency by reducing conduction losses, which is suboptimal in applications requiring a small form-factor, such as in implants. This article describes a variable-capacitance harvester that performs optimally using miniaturized inductors. The impact of scaling the inductor on the generated energy of conventional semisynchronous and fully-synchronous charge-constraint topologies is investigated analytically as well as experimentally. It is shown that the proposed harvester outperforms the semisynchronous and fully-synchronous charge-constraint harvesters while using very small inductance values. Using two reservoir capacitors to generate energy without requiring large inductors, as well as utilizing a different switching scheme are the main factors contributing to this advantage. Since harvesting energy from slow moving mechanical sources, such as body movements, constitutes a major challenge, all three harvesters are implemented and tested with an actuating frequency as low as 0.5 Hz and for inductance values between 1  $\mu$ H to 1 mH. The experimental results for sample designs corroborate the analytical expressions and show that to generate optimal harvested energy of the proposed harvester, the semisynchronous harvester requires a 15.6 times larger inductor. [ABSTRACT FROM AUTHOR]

Convolutional neural networks (CNNs) have been widely applied in the field of computer vision due to their inherent advantages in image feature extraction. However, it is difficult to implement CNNs directly on embedded platforms owing to excessive calculations of CNNs. Field Programmable Gate Arrays have been popular in CNN accelerators because of their configurability and high energy efficiency. Given the highly parallel workloads of the CNN, a CNN accelerator with a 14 × 16 processing element array is designed in this study to accelerate the CNN inference. Besides, a loop tiling strategy for convolutional layers is proposed to efficiently transmit feature maps. Additionally, the roofline model is employed to explore the best tiling parameters for optimal performance. Finally, the accelerator written in Verilog‐HDL language is implemented on the Xilinx Zynq‐7045 evaluation platform. At an operating frequency of 200 MHz, the proposed accelerator can achieve a performance of 57.24 giga operations per second on You Only Look Once v2‐tiny and 78.39 GOPS on Visual Geometry Group‐16. The accelerator only consumes 224 DSPs, demonstrating a better performance compared with the previous works. [ABSTRACT FROM AUTHOR]

Standardless PIGE analysis requires precise differential cross section values. In this research differential cross section data for proton-induced gamma-ray emission for 63Cu and 65Cu in the energy range 2000–3000 keV at 90◦ in the laboratory frame was measured. The research was carried out using the proton beam of the 3 MV Van de Graaff electrostatic accelerator of Nuclear Science and Technology Research Institute (NSTRI) in Tehran. The validity of present data was confirmed through thick target yield benchmarking procedure. The estimated systematic uncertainty is less than 9%. [ABSTRACT FROM AUTHOR]

Aerosol samples (PM10 and PM2.5) were collected during the 2018-2019 dry-cold season, inside an electrostatic particle accelerator laboratory at Instituto de Física, Universidad Nacional Autónoma de México, and on the rooftop. The goal was to measure gravimetric mass and elemental concentrations, to identify emitting sources, and to assess risks to human health due to inhalation, ingestion and dermal deposition, through Hazard Quotients. Concentrations of Mg, Al, Si, P, S, Cl, K, Ca, V, Mn, Fe, Ni, Cu, and Zn were measured with X-ray Fluorescence. Mass concentrations were lower indoors than outdoors. Elemental/gravimetric mass concentrations ratios showed that S, Ni, Cu, and Zn were more abundant in both indoors particle sizes, plus P in PM2.5. Possible sources, found through Cluster Analysis, were geogenic, SF6 subproducts, vacuum pump oil, and air conditioning, supported by Scanning Emission Microscopy and Electron Probe Microanalysis. Health risks due to enriched elements are not significant. [ABSTRACT FROM AUTHOR]

Electrostatic nanogenerators or capacitive sensors that leverage electrostatic induction for power generation or sensing, has attracted significant interests due to their simple structure, ease of fabrication, and high device stability. However, in order for such devices to work, an additional power source or a post-charging process is necessary to activate the electrostatic effect. In this work, an electrostatic nanogenerator is fabricated using electrospun polystyrene (PS) mats and dip-coated graphene oxide (GO) films as the self-charged components. The electret performances of the PS mats and GO films are characterized via the electrostatic force microscopy phase shift and surface potential measurements. With a multilayer device structure that consists of top electrodes/GO films/spacer/electrospun PS mats/bottom electrodes, the resultant device acts as an electrostatic generator that operates in the noncontact mode. The nanogenerator can output a peak voltage of ca. 6.41 V and a peak current of ca. 6.57 nA at a rate of 1 Hz of mechanical compression, and with no attenuation of electrical outputs even after 50 000 cycles over a 13 h period. Furthermore, this as-prepared device is also capable of serving as a self-powered capacitive sensor for detection of tiny mechanical impacts and measurement of human finger bending. This results of this work provides a new avenue to easily fabricate electrostatic nanogenerators with high durability and self-powered capacitive sensors for the detection of small impacts. [ABSTRACT FROM AUTHOR]

Cell-encapsulation is used for preventing therapeutic cells from being rejected by the host. The technology to encapsulate cells in immunoprotective biomaterials, such as alginate, commonly involves application of an electrostatic droplet generator for reproducible manufacturing droplets of similar size and with similar surface properties. As many factors influencing droplet formation are still unknown, we investigated the impact of several parameters and fitted them to equations to make procedures more reproducible and allow optimal control of capsule size and properties. We demonstrate that droplet size is dependent on an interplay between the critical electric potential (Uc,), the needle size, and the distance between the needle and the gelation bath, and that it can be predicted with the equations proposed. The droplet formation was meticulously studied and followed by a high-speed camera. The X-ray photoelectron analysis demonstrated optimal gelation and substitution of sodium with calcium on alginate surfaces while the atomic force microscopy analysis demonstrated a low but considerable variation in surface roughness and low surface stiffness. Our study shows the importance of documenting critical parameters to guarantee reproducible manufacturing of beads with constant and adequate size and preventing batch-to-batch variations. [ABSTRACT FROM AUTHOR]

Differential cross sections for gamma-ray emission from the 107Ag (p, p′γ 3-0)107Ag and 109Ag (p, p′γ 3-0)109Ag reactions in the proton energy range 1200–2700 keV were measured at 90⁰ in the laboratory frame. In addition, differential cross sections for gamma-ray emission from the 107Ag(p, p′γ 4-0)107Ag and 109Ag(p,p′γ 4-0)109Ag reactions in the proton energy range 1310–2700 keV and 1330–2700 keV in the mentioned condition. The measurements were performed using the proton beam of the 3 MV Van de Graaff electrostatic accelerator of Nuclear Science and Technology Research Institute (NSTRI) in Tehran. Besides, the validity of the measured differential cross sections was verified through comparison between calculated thick target yields deduced from present work excitation curve and experimental thick target yield data available from literature. The overall systematic uncertainty of the measured values was estimated to be less than 8%. [ABSTRACT FROM AUTHOR]

• Ion beams were pulsed successfully in a wide range of parameters. • The measurements confirm the validity of the expressions used in the design. • Good correlation obtained between observed and theoretical bunched pulsed waveforms. • For the heavy ions, the performance is restricted by transit time variation. A pulsed system capable of delivering up to a few microamps with a mass range 1–100 u, and with pulse width of bursts of ions approximately 1–2 ns is described. Critical design limitations are discussed to show the overall approach to meet a number of experimental requirements. The system consists of a SNICS negative ion source, a low energy buncher which uses the entire tandem electrostatic accelerator as a drift path to produce bunched ion bursts at the targets or linac entry, and high energy choppers. The buncher consists of a single acceleration gap with aligned removable grids. A detailed analysis is presented of the factors limiting the system performance, with the aim to lessen their effect on the ultimate minimum longitudinal phase space of the ion burst. [ABSTRACT FROM AUTHOR]