Trapped Field Research Articles

Simulation of Space Charge Effects in Fourier Transform Quadrupole Ion Traps (FT-QITs).

We present ion dynamics simulations regarding the effect of space charge on the performance of Fourier transform quadrupole ion traps (FT-QITs) with special attention to signal stability, mass resolving power, and sensitivity. Ion trajectory simulations within an idealized QIT geometry are performed by applying a dedicated application (QITSim) using an in-house developed open simulation framework (IDSimF). Image current detection transients are generated by the application and are subsequently transformed into frequency spectra of ion secular motion. Such frequency spectra are the basis for the calculation of mass spectra in FT-QIT instruments. The simulation results are used to assess the extent of space charge induced effects regarding the analytical performance of FT-QIT systems. The simulation results for two Cl+ and seven Xe+ isotope ions exhibit diverse space charge induced phenomena. Most prominently, complete isotope signal fusion, quantitative individual signal suppression, and severe signal distortions are observed even at low absolute numbers of trapped ions. Furthermore, significant shifts of the secular oscillation frequencies occur, even when the signal shape appears to be mostly unaffected and when the frequency separation for trapped ions with different masses is large. This significantly limits the applicability of FT-QIT systems for high resolution mass spectrometry. An increase of the RF amplitude of the trapping field as well as increasing the extent of ion excitation partly mitigate these adverse space charge effects; nevertheless, the usable operational range of the simulated FT-QIT system for analytical applications remains rather narrow.

Asymmetric semiochemical-mediated interactions of Monochamus spp. (Coleoptera: Cerambycidae) and associated bark beetles in Portugal and Canada.

Some coniferophagous bark and woodboring beetles overlap spatially and temporally in host trees. These larval interactions have been classified as competitive and predatory in favor of the larger and more mobile woodborer larvae. In some bark beetles, larval traits have been reported that facilitate evasion of woodborer larvae. Both bark beetles and woodborers mediate mating on host material with volatile pheromones. Although it is known that some woodborers eavesdrop on bark beetle aggregation pheromones to facilitate host location, it is not known what effect woodborer pheromones have on bark beetles. The pheromone monochamol is used by most Monochamus spp. Dejean and coniferophagous species from this genus co-occur with bark beetles in host tissues. Because of the negative consequences these larval interactions have for bark beetles, we hypothesized that the woodborer pheromone monochamol would inhibit captures of sympatric and synchronic bark beetles to intercept traps baited with their aggregation pheromones and host volatiles. We tested this hypothesis in 2 systems, 1 in Ontario, Canada, and another in Setúbal, Portugal with field trapping experiments. Trap captures of Ips sexdentatus (Boerner) (Coleoptera: Scolytinae), Orthotomicus erosus (Wollaston) (Coleoptera: Scolytinae) (2 bark beetle species captured in Portugal), and Ips pini (Say) (Coleoptera: Scolytinae) (1 bark beetle species captured in Canada) were reduced by the presence of monochamol. These results suggest that an additional evasion mechanism in some bark beetles is the detection of the woodborer pheromone monochamol and subsequent reduced response to aggregation pheromone and host volatiles in the presence of this woodborer pheromone.

Sex Pheromone Mediates Resource Partitioning Between Drosophila melanogaster and D. suzukii.

The spotted-wing drosophila, Drosophila suzukii and the cosmopolitan vinegar fly D. melanogaster feed on soft fruit and berries and widely overlap in geographic range. The presence of D. melanogaster reduces egg-laying in D. suzukii, possibly because D. melanogaster outcompetes D. suzukii larvae feeding in the same fruit substrate. Flies use pheromones to communicate for mating, but pheromones also serve a role in reproductive isolation between related species. We asked whether a D. melanogaster pheromone also modulates oviposition behaviour in D. suzukii. A dual-choice oviposition assay confirms that D. suzukii lays fewer eggs on blueberries exposed to D. melanogaster flies and further shows that female flies have a stronger effect than male flies. This was corroborated by treating berries with synthetic pheromones. Avoidance of D. suzukii oviposition is mediated by the female D. melanogaster pheromone (Z)-4-undecenal (Z4-11Al). Significantly fewer eggs were laid on berries treated with synthetic Z4-11Al. In comparison, the male pheromone (Z)-11-octadecenyl acetate (cVA) had no effect on D. suzukii oviposition. Z4-11Al is a highly volatile compound that is perceived via olfaction and it is accordingly behaviourally active at a distance from the source. D. suzukii is known to engage in mutual niche construction with the yeast Hanseniaspora uvarum, which strongly attracts flies. Adding Z4-11Al to fermenting H. uvarum significantly decreased D. suzukii flight attraction in a laboratory wind tunnel and a field trapping assay. That a D. melanogaster pheromone regulates oviposition in D. suzukii demonstrates that heterospecific pheromone communication contributes to reproductive isolation and resource partitioning in cognate species. Stimulo-deterrent diversion or push-pull methods, building on combined use of attractant and deterrent compounds, have shown promise for control of D. suzukii. A pheromone that specifically reduces D. suzukii attraction and oviposition adds to the toolbox for D. suzukii integrated management.

Review on high-temperature superconducting REBCO trapped field magnets

Abstract Superconducting (SC) magnets can generate exceptionally high magnetic fields and can be employed in various applications to enhance system power density. In contrast to conventional coil-based SC magnets, high-temperature superconducting (HTS) trapped field magnets (TFMs), namely HTS trapped field bulks (TFBs) and trapped field stacks (TFSs), can eliminate the need for continuous power supply or current leads during operation and thus can function as super permanent magnets. TFMs can potentially trap very high magnetic fields, with the highest recorded trapped field reaching 17.89 T, achieved by TFSs. TFMs find application across diverse fields, including rotating machinery, magnetic bearings, energy storage flywheels, and magnetic resonance imaging (MRI). However, a systematic review of the advancement of TFMs over the last decade remains lacking, which is urgently needed by industry, especially in response to the global net zero target. This paper provides a comprehensive overview of various aspects of TFMs, including simulation methods, experimental studies, fabrication techniques, magnetisation processes, applications, and demagnetisation issues. Several respects have been elucidated in detail to enhance the understanding of TFMs, encompassing the formation of HTS bulk composites and TFSs, trapped field patterns, enhancement of trapped field strength through pulsed field magnetisation (PFM), as well as their applications such as SC rotating machines, levitation, and Halbach arrays. Challenges such as demagnetisation, mechanical failure, and thermal instability have been illuminated, along with proposed mitigation measures. The different roles of ferromagnetic materials in improving the trapped field during magnetisation and in reducing demagnetisation have also been summarised. It is believed that this review article can provide a useful reference for the theoretical analysis, manufacturing, and applications of TFMs within various domains such as materials science, power engineering, and clean energy conversion.

Movable surface acoustic wave tweezers: a versatile toolbox for micromanipulation

Surface acoustic wave (SAW) tweezers are a promising multifunctional micromanipulation method that controls microscale targets via patterned acoustic fields. Owing to their device structure and bonding process, most SAW tweezers have limitations in terms of controlling the position and motion of the acoustic traps, as they generate an acoustic field with a fixed region and adjust the manipulation effects via signal modulation. To address this challenge, we propose movable SAW tweezers with a multilayer structure, achieving dynamic control of their wave field and acoustic trap positions; we demonstrate their precise manipulation functions, such as translation, in-plane rotation, out-of-plane rotation, and cluster formation, on a wide spectrum of samples, including particles, bubbles, droplets, cells, and microorganisms. Our method not only improves the degree of freedom and working range of SAW tweezers but also allows for precise and selective manipulation of microtargets via microtools and localized wavefields. Owing to their flexibility, versatility, and biocompatibility, the movable SAW tweezers can be a practical platform for achieving arbitrary manipulation of microscale targets and have the potential to play significant roles in biomedical microrobotics.

Response of hibiscus mealybug (Hemiptera: Pseudococcidae) to citrus volatiles induced by mechanical injury.

Hibiscus mealybug, Nipaecoccus viridis (Newstead) (Hemiptera: Pseudococcidae), is a recent invasive pest of citrus and many other crops in Florida. Nipaecoccus viridis attacks all above ground parts of citrus trees and heavy infestation can cause leaf drop and premature abortion of developing fruits. We quantified greater captures of N. viridis in cardboard band traps on areas of citrus trees that were intentionally injured by mechanical rasping of epidermal tissues as compared with similar but uninjured citrus branches. Direct field collection of headspace volatiles from mechanically injured or intact citrus branches revealed both qualitative and quantitative differences. Certain volatiles (γ-terpinene, citronellal, citronellyl acetate, β-E-farnesene, α-humulene, and α-E-E-farnesene) were only present in samples from damaged citrus branches. Behavioral assays using a laboratory Y-tube olfactometer revealed attraction of N. viridis to volatiles associated with mechanical damage of citrus including synthetic β-ocimene, γ-terpinene, sabinene, isomers of farnesene, and citronellal when loaded into lures at either of 2 concentrations (0.01 or 0.1 µg/µl). Subsequent field trapping experiments confirmed increased captures of various life stages of N. viridis in cardboard band traps baited with a 10.0 µg/µl concentration of farnesene:ocimene:sabinene blend (in 7:13:17 ratio), as well as those releasing either farnesene or ocimene alone at this same concentration, as compared with the mineral oil (diluent) negative control. Our results indicate that common plant related terpenes released by citrus following mechanical damage may be useful for development of an effective monitoring trap for N. viridis.

Excellent field–trapping properties of large ring–shaped REBCO melt–textured bulks fabricated by the single–direction melt growth (SDMG) method

Abstract Ring-shaped homogeneous YBCO and DyBCO bulks were successfully fabricated using the Single-Direction Melt Growth (SDMG) method. The bulks were directly grown from ring-shaped compacted powder using ring-shaped molds with an outer diameter of 50 mm and inner diameters of 15, 20, and 25 mm. The ring-shaped bulks exhibited high trapped fields inside the rings up to 1.2 T at 77 K. Analyses of trapped field distributions revealed uniform current density distributions along the orbital direction. Stacked ring bulks demonstrated even higher trapped fields, reaching 2.0 T at 77 K. It was confirmed for the stacked bulks that time-independent uniform trapped fields can be achieved by magnetizing at lower fields than fully magnetizing conditions. Observed paramagnetic magnetization of the SDMG-processed YBCO bulk was negligibly small below the detection limit, which is considered to be more suitable for bulk NMR/MRI applications than DyBCO. Additionally, we proposed a method to quantitatively evaluate trapped fields of superconducting bulks with various diameters and thicknesses, where the estimated average current densities from the maximum trapped fields for all the obtained ring-shaped bulks were above 104 A/cm2 at 77 K. These results indicate that SDMG is an effective method for fabricating high-quality, large-scale ring-shaped bulks with superior field-trapping properties.

Behavioral responses of predatory flies of the genus Medetera Fischer von Waldheim (Diptera: Dolichopodidae) and the tree-killing beetle Ips typographus L. (Coleoptera: Scolytinae) to odor compound blends

Key MessageMedetera (Fischer von Waldheim) flies, natural enemies of the spruce bark beetle Ips typographus (L.), were attracted to synthetic blends of compounds produced by infested spruce trees. A subset of trapped specimens revealed sixteen Medetera species. Most abundant were M. signaticornis, M. infumata, and M. prjachinae. Only blends containing beetle-produced compounds significantly attracted Medetera spp. and I. typographus.ContextFly species of the genus Medetera (Fischer von Waldheim) (Diptera: Dolichopodidae) represent one of the most important groups of natural enemies of the Eurasian bark beetle Ips typographus (L.), which infests Norway spruce Picea abies (L.) Karst. In a previous study, we showed that adult Medetera flies exploit semiochemicals to find beetle-infested trees however, the exact nature of those attractive compounds has not yet been determined.AimsThe aim of this follow-up study was to investigate the behavioral responses of Medetera spp. and I. typographus, to different combinations of semiochemicals.MethodsIn this study, 22 volatile compounds identified from I. typographus-infested Norway spruce were divided into five groups (A–E) based on being primarily produced by the bark beetle I. typographus (group A), bark beetle-associated microorganisms (groups B and C), or spruce tree (groups D and E). The effect of the compounds in these groups in the attraction of Medetera species and I. typographus was tested in two different subtractive field trapping assays.ResultsIn the first subtractive assay, the full blend (ABCDE), and the blends lacking microbial compounds of group C, or spruce tree compounds of group D led to significant attraction of Medetera flies. Morphological identification of a subset of the specimens collected revealed that sixteen species were attracted to the synthetic blends, with M. signaticornis Loew being the most abundant. In the second subtractive assay, high attraction of Medetera flies and I. typographus was found for a 12-component synthetic blend.ConclusionThe insights gained provide a basis for developing synthetic attractants to facilitate monitoring of Medetera flies. Future testing and optimization of these attractants will enhance our ability to monitor, conserve and utilize Medetera flies, thereby enabling us to better protect forests from the damaging effects of spruce bark beetles.

Navigation of superparamagnetic particles with a pre-magnetized high-temperature superconducting bulk in a weak background field

Abstract Recent research has shown significant progress towards a full body magnetic drug delivery (MDD) system for use in targeted cancer treatments. Although many different MDD systems have been proposed to generate strong remote forces capable of rapidly changing directions at distances greater than 10 cm, current state-of-the-art technologies lack in force strength and/or degrees of freedom. Knowing that high temperature superconducting (HTS) bulks can achieve trapped fields an order of magnitude larger than ferromagnets, this work aims at numerically and experimentally evaluating the forces that can be produced by HTS bulks in a uniform magnetic field. We first use Hall probe measurements and finite element simulations to determine the magnetic field generated by an HTS pellet and show that both results are in good agreement. Using a combination of simulations and experiments, we then show that for a 14 × 6 mm YBa2Cu3O 7 − x pellet magnetized at 2 T, remote forces on superparamagnetic microparticles are maximized at background fields of ∼50 mT. In addition, the direction of the magnetic forces can be flipped by changing the direction of the applied field relative to the HTS’s magnetization. The HTS bulk was successfully used to navigate magnetic microparticles in a glass bifurcation mimicking the hepatic artery of the human liver. Finally, we show by simulation that a large HTS pellet magnetized at 5 T in a field of ∼250 mT can generate stronger forces with more degrees of freedom than the strongest forces achievable in current MDD technologies.

Inhibitory activity of some short-chain aliphatic aldehydes on pheromone and ammonium carbonate-mediated attraction in olive fruit fly, Bactrocera oleae.

The olive fruit fly (OFF), Bactrocera oleae (Rossi), is the main insect pest of olive trees worldwide. Legislation limits to the use of some synthetic larvicidal insecticides is leading to the development of new control options for preventive control of adult flies. In the present study, the biological activity of four short-chain aliphatic aldehydes, namely hexanal, (E)-2-hexenal, heptanal and (E)-2-heptenal, previously reported as repellents to the OFF adults was investigated. Electroantennography (EAG) recordings showed that antennae of OFF males and females are able to perceive the test compounds in a wide range of doses. In field trapping experiments, reservoir-type polypropylene (PP) membrane dispensers loaded with individual compounds did not elicit a significant attraction of OFF males and females. On the contrary, a significant reduction of male catches was noticed when sex pheromone dispensers and PP membrane dispensers, loaded with one of the test compounds, were applied on the same white sticky traps ≈20 cm apart. Likewise, male and female catches in yellow sticky traps baited with ammonium carbonate (AC) dispensers as food attractant were significantly reduced by the presence of PP membrane dispensers of individual aliphatic aldehydes on the same traps. In small plots control trials, solid formulations of the four aldehydes into a bentonite clay support induced a significant reduction of the OFF active infestation mainly when C6 and C7 aldehyde-activated bentonites were used. Short-chain aliphatic aldehydes showed inhibitory effects on sex pheromone and food attractant-mediated attraction of OFF. Results of field trials suggest potential of short-chain aliphatic aldehydes to develop new semiochemical-based OFF control options. © 2024 Society of Chemical Industry.

Comparison of Levitation Properties between Bulk High-Temperature Superconductor Blocks and High-Temperature Superconductor Tape Stacks Prepared from Commercial Coated Conductors.

Bulk high-temperature superconductors (HTSs) such as REBa2Cu3O7-x (REBCO, RE = Y, Gd) are commonly used in rotationally symmetric superconducting magnetic bearings. However, such bulks have several disadvantages such as brittleness, limited availability and high costs due to the time-consuming and energy-intensive fabrication process. Alternatively, tape stacks of HTS-coated conductors might be used for these devices promising an improved bearing efficiency due to a simplification of manufacturing processes for the required shapes, higher mechanical strength, improved thermal performance, higher availability and therefore potentially reduced costs. Hence, tape stacks with a base area of (12 × 12) mm2 and a height of up to 12 mm were prepared and compared to commercial bulks of the same size. The trapped field measurements at 77 K showed slightly higher values for the tape stacks if compared to bulks with the same size. Afterwards, the maximum levitation forces in zero field (ZFC) and field cooling (FC) modes were measured while approaching a permanent magnet, which allows the stiffness in the vertical and lateral directions to be determined. Similar levitation forces were measured in the vertical direction for bulk samples and tape stacks in ZFC and FC modes, whereas the lateral forces were almost zero for stacks with the REBCO films parallel to the magnet. A 90° rotation of the tape stacks with respect to the magnet results in the opposite behavior, i.e., a high lateral but negligible vertical stiffness. This anisotropy originates from the arrangement of decoupled superconducting layers in the tape stacks. Therefore, a combination of stacks with vertical and lateral alignment is required for stable levitation in a bearing.

Effect of temperature and humidity on insect DNA integrity evaluated by real-time PCR.

Insects collected in dry traps can degrade rapidly, especially in warm, humid environments where many biodiversity and biosecurity surveillance activities are undertaken. Degradation can severely impact diagnostics, as trap catches can become difficult to identify to species level using morphological characters or, of increasing importance, molecular approaches. This is especially problematic for biosecurity surveillance of exotic tephritid fruit flies, where diagnostics are heavily reliant on morphological characters. We tested the effects of differing temperature and humidity conditions on mock samples of tephritid fruit flies in a controlled environment and compared our results to field trap catches. DNA degradation was quantified using real-time PCR assays, including one assay newly developed and tested here. We observed a correlation between increasing DNA degradation and increasing temperature and humidity. The greatest DNA degradation occurred under combined high humidity (90% relative humidity) and constant high temperature (35 °C). Unexpectedly, fluctuating temperature did not have a significant impact on DNA. Other factors, such as trap design, time in the field, and rainfall, did not significantly correlate with DNA quality across the field samples tested. When plotted against mock samples, field samples clustered together, with no clear pattern or predictability regarding the quantity of DNA preserved, indicating other untested environmental variables may be at play. Predictably, increased exposure time was found to have a detrimental effect on DNA quality for all treatments. These findings will improve the delivery of surveillance activities through the implementation of shorter trap clearance timeframes and improved trap designs and procedures.

Establishing the distribution of Carpophilus truncatus in Australia using an integrative approach for an emerging global pest

The nitidulid beetle Carpophilus truncatus is rapidly becoming a major pest of nut crops around the world. This insect first infested Australian almonds in 2013 and has since escalated to be the preeminent insect pest for the industry. Data pertaining to C. truncatus distribution are scant, but without awareness of its origin, distribution, and ecological factors that influence distribution, efforts to understand and manage the insect as a pest are stymied. Here, we employ an integrative approach to gain a multifaceted understanding of the distribution of C. truncatus in Australia. Methods employed were (1) reviewing historical records in insect collections to establish the presence of C. truncatus prior to commercial almond horticulture, (2) field trapping of insects to establish presence in regions of interest, (3) laboratory trials to determine the thermal limits of the organism, and (4) correlative species distribution modelling to describe its current distribution. We find that C. truncatus is more widespread across Australia than was previously known, with historical records preceding commercial almond production in Australia by a century. The methods developed in this study can be applied elsewhere in the world where C. truncatus is an emerging pest, or to novel pest species as they arise with increasing frequency in a globalised and warming world.

A numerical approach to levitated superconductors and its application to a superconducting cylinder in a quadrupole field

Abstract Magnetically levitated superconductors in the Meissner state can be utilized as micro-mechanical oscillators with large mass, high quality factors and long coherence times. In previous works analytical solutions for the magnetic field distribution around a superconducting sphere in a quadrupole field have been found and used to derive the trap parameters, while non-spherical geometries have only been investigated in a few idealized cases. However, superconductors of almost arbitrary shape can be used as levitators in a magnetic trap and, as the trap’s properties depend strongly on the superconductor’s shape, allow for a wider parameter regime to be accessed. Finite element models are suitable to obtain the field distribution around arbitrarily shaped superconductors in arbitrary fields, but have not yet been used widely in the context of levitated superconductors. Here we present a simple numerical model for this purpose and use it to calculate the field distribution around cylindrical superconductors in a quadrupole field and to evaluate the trap parameters. We find that the cylindrical shape, compared to spherical levitators, allows for substantially higher trap frequencies and coupling strengths. This in turn reduces the demands on vibration isolation and significantly eases the requirements for feedback cooling to the ground state. The numerical model is provided in a file repository and can easily be adapted to various geometries and trap fields.

Effect of heating and bending on localized critical current in 2G HTS tapes with non-contact trapped field measurements

Current-voltage measurement (I–V curve) is a typical method to identify the critical current (Ic) of second-generation high-temperature superconducting tapes (2G HTS tapes). However, it is difficult to characterize the local Ic of 2G HTS tape on the millimeter (mm) scale due to the set spacing of the voltage electrodes (several centimeters), so non-contact trapped field distribution measurements have been used to define local defects in Y–Ba–Cu–O bulks and 2G HTS tapes, especially for the quality analysis for long lengths of 2G HTS tapes. In order to discuss the possible degradation of 2G HTS tape during heating and bending (both important parameters in joining process), this study used both trapped field measurement and I–V measurement to characterize the effect of heating (190 °C–230 °C) and bending (radius = 3.75 mm–22.35 mm) processes on the degradation of 2G HTS tape Ic. In addition, according to electromagnetic calculations, the local Ic (within a few millimeters) of the 2G HTS tape can be obtained from the flux density and distribution of the trapped magnetic field. Comparing the two sets of Ic measurements showed very good agreement. This study demonstrates the accuracy of optimized heating and bending parameters as well as spatial position and local Ic values of processed 2G HTS tape through non-contact trapped field measurements.

Enhancing the magnetic field gradient between two superconductors with rotational motion under a background DC field

The ability of bulk high-temperature superconductors to trap magnetic flux densities up to one order of magnitude larger than the saturation magnetization of conventional ferromagnetic materials offers the prospect of generating large magnetic flux density gradients. Combining multiple superconductors, akin to assembling a Halbach array of permanent magnets, may increase the generated gradient even further. The associated challenge is that superconductors are prone to demagnetization when exposed to field components perpendicular to their main magnetization direction. In the present work, we investigate the magnetic flux density gradient achieved with a pair of cubic, bulk, large-grain melt-textured superconductors in the presence of a background DC magnetic field at 77 K. We investigate the increase of the performance when decreasing the temperature down to 59 K. The studied configuration consists in two facing cubic YBa2Cu3O 7−x superconductors of 6 mm side with anti-parallel magnetization directions. It is obtained after the simultaneous magnetization of the samples followed by a rotation of 180∘ of the top superconductor. Although the background field reduces the trapped field ability of individual samples, it is shown that this phenomenon is significantly mitigated at 65 K and at 59 K compared to 77 K. The results reveal that a sample-to-sample distance ( ∼16 mm) of the order of their size is sufficient to avoid any mutual demagnetization effect during the rotational motion. Furthermore, it is shown that decreasing the temperature is not only beneficial in increasing the field and field gradient achieved but also in extending the range of background fields in which the superconductor can be rotated without demagnetization. This superconducting assembly yields a magnetic flux density gradient exceeding that of an isolated superconductor and has the potential to surpass the capabilities of permanent magnets.

Characterisation of Large-Sized REBaCuO Bulks for Application in Flux Modulation Machines.

High temperature superconductors (HTSs) are enablers of extensive electrification for aircraft propulsion. Indeed, if used in electrical machines, HTS materials can drastically improve their performance in terms of the power-to-weight ratio. Among the different topologies of superconducting electrical machines, a flux modulation machine based on HTS bulks is of interest for its compactness and light weight. Such a machine is proposed in the FROST (Flux-barrier Rotating Superconducting Topology) project led by Airbus to develop new technologies as part of their decarbonization goals driven by international policies. The rotor of the machine will house large ring-segment-shaped HTS bulks in order to increase the output power. However, the properties of those bulks are scarcely known and have barely been investigated in the literature. In this context, the present work aims to fill out partially this scarcity within the framework of FROST. Thus, a thorough characterisation of the performances and homogeneity of 11 large REBaCuO bulks was carried out. Ten of the bulks are to be utilized in the machine prototype, originally keeping the eleventh bulk as a spare. A first set of characterisation was conducted on the eleven bulks. For this set, the trapped field mapping and the critical current were estimated. Then, a series of in-depth characterisations on the eleventh bulk followed. It included critical current measurement, X-ray diffraction, and scanning electron microscopy on different millimetre-size samples cut out from the bulk at various locations. The X-ray diffraction and scanning electron microscopy showed weakly oxygenated regions inside the bulk explaining the local drop or loss in superconducting properties. The objective was to determine the causes of the inhomogeneities found in the trapped field measured on all the bulks, sacrificing one of them, here the spare one. To help obtain a clearer picture, a numerical model was then elaborated to reproduce the field map of the eleventh bulk using the experimental data obtained from the characterisation of its various small samples. It is concluded that further characterisations, including the statistics on various bulks, are still needed to understand the underlying reasons for inhomogeneity in the trapped field. Nonetheless, all the bulks presented enough current density to be usable in the construction of the proposed machine.

A novel nanofiltration membrane with a dual-charged layer to simultaneously remove anions and cations from acid mine drainage

A novel nanofiltration (NF) membrane with a positively and negatively dual-charged layer was finely designed in this study. The membrane was prepared by co-deposition of 4-tert-butylpyrocatechol (TBC) and polyethyleneimine (PEI) and electrostatic interaction to assemble positively and negatively charged functional layers on a substrate which is polyamide (PA)-based NF membrane. The NF membrane achieved excellent retention capacity through the combined effects of Donnan repulsion and electrostatic field trapping. The prepared membrane had a dense but thin surface layer with an average pore size of 0.84 nm, enabling an improved membrane flux of 8.66 L/(m2·h·bar) and high rejection to divalent inorganic salt ions (93.56 % Mg2+, 99.56 % SO42-). The membrane was used to treat acid mine drainage (AMD) and achieved an excellent retention capacity for ions in AMD (93.25 % Mg2+, 91.58 % Ca2+, 94.22 % Mn2+, 95.96 % SO42-), meeting industrial wastewater discharge standards. In addition, the NF membrane demonstrated good anti-fouling performance during the AMD treatment and significant potential for environmental remediation applications.

Confirmation that Monochamol is a Male Produced Aggregation-Sex Pheromone for Monochamus maculosus Haldeman (Coleoptera: Cerambycidae).

The recognition of cerambycids as frequent and damaging invaders led to an increase in the interest in the chemical ecology of the group with the identification of pheromones and pheromone-like attractants for well over 100 species. Pheromone components of the Cerambycidae are often phylogenetically conserved, with a single compound serving as a pheromone component for several related species. In the subfamily Lamiinae, the compound 2-(undecyloxy)ethanol (monochamol) has been identified as an aggregation-sex pheromone for several species of the genus Monochamus. In other species, including Monochamus maculosus Haldeman, field trials have demonstrated that monochamol is a pheromone attractant, but at that point it was still unknown as to whether it was a pheromone for this species. Here we report the identification, and laboratory and field trials of a pheromone component produced by adult male M. maculosus. Chemical analyses of headspace volatile collections sampled from field collected beetles of both sexes revealed the presence of one male-specific compound that was identified as 2-(undecyloxy)ethanol. Electroantennography analyses showed that monochamol elicited responses from the antennae of female beetles. Traps baited with monochamol in the field captured M. maculosus adults of both sexes corroborating the identification of monochamol as the sex-aggregation pheromone of this species. The attractivity of monochamol to adult M. maculosus in our field trapping experiment was synergized by the addition of the host volatile α-pinene.

Identification of the Female Sex Pheromone of Grammodes Geometrica (Lepidoptera: Erebidae: Erebinae).

The female sex pheromone of Grammodes geometrica (Lepidoptera: Erebidae: Erebinae) was identified as a 2:100:4 mixture of (3Z,6Z,9Z)-3,6,9-icosatriene (T20), (3Z,6Z,9Z)-3,6,9-henicosatriene (T21), and (3Z,6Z,9Z)-3,6,9-tricosatriene (T23) through chemical and electrophysiological analyses of female gland extracts. T23 is a novel sex pheromone component in Erebinae species. Field trapping tests demonstrated optimal male captures in attractant-baited traps when using a 2:100:4 blend of T20, T21 and T23, with a significant decrease in captures observed when T20 or T23 were removed from the full blend. Traps were set in early August, but males began to be captured in early September. The seasonal prevalence showed a bimodal peak, occurring on September 11 and October 9. These findings provide valuable insights into the chemical communication and ecological dynamics of this species within the subfamily Erebinae.