Trapping Area Research Articles

Automatic magnetic projection for one-step separation of mixed plastics using ring magnets

Magnetic projection, a novel separation method proposed recently, can separate multiple mixed materials in an efficient and low-cost way. Although promising, existing magnetic projection method cannot achieve the automatic feeding of mixed materials, which limits its applications. To address this challenge, ring magnets were used to replace conventional square magnets in this research. Specifically, a mixture of particles with different densities were fed through the hole of ring magnets and then projected to the corresponding area. Moreover, to increase the magnetic field strength, magnets were superimposed. To predict the projection process, magnetic field analysis was conducted. And from the results, an interesting trap area was found, where the separated materials may be constrained, leading to the failure of projection. The simulation of the projection process revealed that with the increase of the number of magnets (1–3 magnets), the magnetic field strength increased. However, the projection distance will not keep increasing with the increase of the magnetic field strength, which also was verified by experiments (Err within 10%). Based on this principle, an automatic feeding device with ring track and pendulum was designed and manufactured. In the separation experiment, six different plastics, that were PP, ABS, PC, PLA, PET and PVC, were used to verify the separation effect. The experimental results showed that the proposed method can automatically separate a plastic mixture with a recovery rate of over 95%. This study presents a break-through in magnetic projection, laying the foundation for the practical application of magnetic projection.

The effects of a zoo environment on free‐living, native small mammal species

One of the main threats to native species conservation is urbanisation. It is causing changes to natural habitats and species composition. Urban green spaces have shown to have conservation value for native species by providing safe spaces in urban areas. They typically contain a variety of habitats and plant species which is correlated with greater abundance and diversity of small mammal species. Zoos are a vital resource for animal conservation and, in some instances, could be considered as an urban green space for native species conservation. Their unique environment provides free-living, native species an abundance of resources including food and shelter. This project involved the live trapping of free-living small mammal species (<40 g) between enclosures in Dudley Zoological Gardens to study the effects of the zoo environment. There were no significant differences found between the total number of captures and trap proximity to enclosures. There was a significant difference in total captures found between different enclosure trapping areas. Generalized linear mixed models were fitted to the data and there were significant relationships between abundance and both habitat type and enclosure species. Habitats associated with semi-natural woodland had the greatest diversity and total captures of small mammals. Total captures were lower in trapping areas that were associated with predatory species. Similar to research on green spaces, habitat was an important factor determining abundance, but predator enclosures were a factor unique to zoos. This study illustrates the potential of zoos as an urban green space and for the study of small mammals.

Optical conveyor belt based on a plasmonic metasurface with polarization dependent hot spot arrays.

In this Letter, we propose a novel metasurface conveyor belt with periodic orientated arrays of gold plasmonic elliptical elements (GPEEs), which can be continuously lit in a relay way by switching the polarization of the excitation beam and can be used to trap, transport, and sort particles. The array of the hot field can provide a larger trapping area and better stiffness. With the incident optical intensity of 0.08mW/µm2, the depth of the potential well could be as high as 10KBT. By setting a narrow interval between plasmonic ellipses in principal axes, it can help further enhance their directional resonant coupling and polarization dependence. Furthermore, based on consideration of the Brownian motion of trapped particles in aqueous solution, we analyzed its time response property of particle manipulation with different applied switching frequencies from a statistical point of view. As confirmed by numerical analysis, our design offers a novel scheme of particle sorting using a scalable hot spot array with better performance, which could be used in many on-chip optofluidic applications.

Plasmonic optical trapping of nanoparticles using T-shaped copper nanoantennas.

We demonstrate the optical trapping of single dielectric nanoparticles in a microfluidic chamber using a coupled T-shaped copper plasmonic nanoantenna for studying light-matter interaction. The nanoantenna is composed of two identical copper elements separated by a 50 nm gap and each element is designed with two nanoblocks. Our nanoantenna inherits three different advantages compared to previous plasmonic nanoantennas, which are usually made of gold. First, copper is a very promising plasmonic material with its very similar optical properties as gold. Second, copper is comparably cheap, which is compatible with industry-standard fabrication processes and has been widely used in microelectronics. Third, the trapping area of tweezers is expanded due to the intrinsic Fabry-Perot cavity with two parallel surfaces. We present finite element method simulations of the near-field distribution and photothermal effects. And we perform Maxwell stress tensor simulations of optical forces exerted on an individual nanoparticle in the vicinity of the nanoantenna. In addition, we examine how the existence of an oxide layer of cupric oxide and the heat sink substrate influence the optical trapping properties of copper nanoantennas. This work demonstrates that the coupled T-shaped copper nanoantennas are a promising means as optical nanotweezers to trap single nanoparticles in solution, opening up a new route for nanophotonic devices in optical information processing and on-chip biological sensing.

All-Fiber Hollow Bessel-Like Beam for Large-Size Particle Trap

A 32 μm large-size microparticle is trapped by an all-fiber hollow Bessel-like beam. In order to realize the proposed high-order Bessel-like beam, we fabricate the optical fiber probe by splicing an annular core fiber with a step-index multimode fiber. We grind the fiber tip into a truncated cone shape to converge the hollow Bessel-like beam to obtain a large focal area. Simulation and experimental results show that the trapping field introduced by the Bessel-like beam provides a relatively strong optical force and has the capability of 3-D capture of a large particle (whose diameter is 32 μm). These highly integrated fiber tweezers provide hollow Bessel-like beams with strong optical force and large trapping area, which can be promisingly applied in biomedical and integrated optical research.

Influence of the height of multilure traps in the collection of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae)

The Mediterranean fruit fly Ceratitis capitata (Wiedemann) is a polyphagous pest adapted to tropical and subtropical climates, which are responsible for the highest share of fruit production. Fruit fly surveys are frequently done by installing traps at heights easily reached by the collector, between 1.5 and 2.5 meters. This study aims to inform fruit fly monitoring strategies by assessing two trap heights (around 2 m and 10 m) in four environments (agricultural and forest) at the “Luiz de Queiroz” Campus, Piracicaba, São Paulo state, Brazil. Each collection environment was considered a block, and eight multilure traps were installed at each of the two heights on four plants per block. A generalized linear model was used for non-normal data with negative binomial distribution to compare the abundance of C. capitata between trap heights and areas. The higher traps, positioned at around 10 m, collected significantly more specimens of C. capitata than those at approximately 2 m in height. The Mediterranean fruit fly was more frequent in the cultivated environments and areas with human activity than in natural areas.

Spatio-temporal impacts of aerial adulticide applications on populations of West Nile virus vector mosquitoes

BackgroundAerial applications of insecticides that target adult mosquitoes are widely used to reduce transmission of West Nile virus to humans during periods of epidemic risk. However, estimates of the reduction in abundance following these treatments typically focus on single events, rely on pre-defined, untreated control sites and can vary widely due to stochastic variation in population dynamics and trapping success unrelated to the treatment.MethodsTo overcome these limitations, we developed generalized additive models fitted to mosquito surveillance data collected from CO2-baited traps in Sacramento and Yolo counties, California from 2006 to 2017. The models accounted for the expected spatial and temporal trends in the abundance of adult female Culex (Cx.) tarsalis and Cx. pipiens in the absence of aerial spraying. Estimates for the magnitude of deviation from baseline abundance following aerial spray events were obtained from the models.ResultsAt 1-week post-treatment with full spatial coverage of the trapping area by pyrethroid or pyrethrin products, Cx. pipiens abundance was reduced by a mean of 52.4% (95% confidence intrval [CI] − 65.6, − 36.5%) while the use of at least one organophosphate pesticide resulted in a mean reduction of 76.2% (95% CI − 82.8, − 67.9%). For Cx. tarsalis, at 1-week post-treatment with full coverage there was a reduction in abundance of 30.7% (95% CI − 54.5, 2.5%). Pesticide class was not a significant factor contributing to the reduction. In comparison, repetition of spraying over three to four consecutive weeks resulted in similar estimates for Cx. pipiens and estimates of somewhat smaller magnitude for Cx. tarsalis.ConclusionsAerial adulticides are effective for achieving a rapid short-term reduction of the abundance of the primary West Nile virus vectors, Cx. tarsalis and Cx. pipiens. A larger magnitude of reduction was estimated in Cx. pipiens, possibly due to the species’ focal distribution. Effects of aerial sprays on Cx. tarsalis populations are likely modulated by the species’ large dispersal ability, population sizes and vast productive larval habitat present in the study area. Our modeling approach provides a new way to estimate effects of public health pesticides on vector populations using routinely collected observational data and accounting for spatio-temporal trends and contextual factors like weather and habitat. This approach does not require pre-selected control sites and expands upon past studies that have focused on the effects of individual aerial treatment events.Graphical

Analysis of Pressure Pulsation in Aviation Gear Pump

In order to analyse the influence of gear parameters on the internal pressure pulsation of the aviation gear pump, the flow field analysis software PumpLinx is used to calculate the internal flow field of the aviation gear pump. By setting monitoring points inside the gear pump under different gear parameters, the pressure pulsation results at different positions under different gear parameters are obtained and analysed. The results show that the larger the modulus, the greater the pressure pulsation in the oil inlet area, oil trapped area and the oil outlet area; the greater the number of teeth, the greater the pressure pulsation in the oil trapped area, and the smaller the impact on the oil inlet area and oil outlet area; the larger the index circle pressure angle, the smaller the pressure pulsation in the trapped oil area, and the smaller the impact on the oil inlet area and the oil outlet area. The analysis results provide a reference for further optimizing the internal pulsation and oil trapping problems of aviation gear pumps.

Simulation Research on Trapped Oil Pressure of Involute Internal Gear Pump

The main structure of an internal gear pump consisted of an internal gear pair, including an internal gear and an external gear. The internal gear pump had oil trapping phenomenon like other hydraulic gear pumps. In order to solve the oil trapping phenomenon of involute gear pump with internal meshing tooth profile, in this paper, the mathematical equation of gear outer contour is established according to the principle of generation method, and the variation law of the trapped oil area in meshing process is deduced by theoretical instantaneous flow rate obtained by scanning method. Then, the minimum trapped oil volume and unloading area are solved by the graphic method. Finally, based on fluid mechanics and dynamics, the trapped oil pressure model is obtained. The change of the trapped oil area and trapped oil pressure in a meshing cycle is simulated by MATLAB. The results show that the trapped oil area changes in a parabola, and the trapped pressure fluctuates in mountains and valleys. When the trapped area is the smallest, the trapped oil pressure reaches the peak at the corresponding corner. The research results can provide guidance for the development of high-performance internal gear pumps.

Trapping two types of Rayleigh particles simultaneously by a focused rotational elliptical Laguerre–Gaussian correlated Schell-model beam

We analyze the optical radiation forces, produced by a focused rotational elliptical Laguerre–Gaussian correlated Schell-model (ELGSM) beam, on the dielectric particles of different refractive indices in the Rayleigh scattering regime. It is found that through a judicious modulation of the initial spatial coherence width and the beam order of the correlation function of the rotational ELGSM beam, the particles with higher refractive index (compared with the ambient) can be trapped along an elliptical ring centered at the focus, the particles with lower refractive index, at the same time, will be trapped at the focal point. Our results also show that the trapping area/range can be modulated by structuring the correlation function of the beam. By comparing the gradient, scattering, Brownian, and gravity forces acting on the particles, the trapping stability is analyzed. Our results indicate that the coherence structure engineering can be used as an alternative approach to modulate the symmetry of the optical trapping area.

WITHDRAWN: Detection of carcinoma cell using single cell trap array

Carcinoma cell (Cancer cell) detection is one of the important aspects in the field of medical industry. Singular cells can be distinguished based on contrasts in size and dielectric properties utilizing electrical procedures that are non-obtrusive. In this paper we have proposed a microfluidic based horizontal trapping model to trap single cancer cell. The variation in impedance at the trapping area is observed when a cell is trapped. The change in the impedance values at the trapping area is an indicator of cancer cell's presence in the blood. Single-cell microfluidic examination frames require innovative responses for individual cell capture and detection.

Photocatalytic carbon dioxide reduction to methanol catalyzed by ZnO, Pt, Au, and Cu nanoparticles decorated zeolitic imidazolate framework-8

Carbon dioxide conversion into valuable industrial products like methanol has gained plenty of attention in recent years. The photocatalytic CO2 reduction is one of the strategies most studied as it is cleaner and has the potential to be more convenient to classical thermochemistry. In this paper, pristine ZIF-8 was decorated with ZnO, Pt, Cu and Au nanoparticles (NPs) to achieve four novel photocatalysts denoted ZnO/ZIF-8, Pt/ZIF-8, Au/ZIF-8, and Cu/ZIF-8 for CO2 reduction to methanol under ultraviolet/visible (UV/Vis) light irradiation at room temperature. All synthesized photocatalysts were fully characterized by XRD, FT-IR, FESEM, TEM, N2 adsorption-desorption, EDS, PL spectroscopy and DRS. DRS revealed successful reduction of the Eg of ZIF-8 up to 71 % after its decoration with NPs. In addition, PL analysis confirmed the efficient hindering of recombination of photoinduced electron-hole pairs in all modified samples. ZnO/ZIF-8 photocatalyst’s features the oxygen vacancies in ZnO NPs, the permanent generation of electron-hole pairs, and an efficient charge-carrier separation due to formation of type II heterojunctions demonstrated higher methanol yield compared to metal NP-impregnated ZIF-8. Interestingly, among metal NPs, Pt/ZIF-8 sample unveiled higher activity toward CO2 photoreduction due to its higher ability to light trapping and higher surface area providing more efficacious interaction of CO2 with the photocatalyst. Moreover, the obtained results demonstrated that methanol production rate over ZnO/ZIF-8 and Pt/ZIF-8 samples can reach 6700 and 5300 μmol.g−1 after 1 h exposure under UV/Vis irradiation, respectively.

Performance of baited traps for integrated management of Hypothenemus hampei Ferrari (Coleoptera: Scolytinae) in a conilon coffee crop in Rondônia State, Brazil

Hypothenemus hampei (Ferrari) is an important pest worldwide. Methods of monitoring and control using baited traps are not yet established in coffee plantations in the Brazilian Amazon. The objective of this work was to record, for the first time, results of the use of baited traps in coffee plantation located in Rondônia, in favor of the control and pest monitoring. Two areas were delineated: i) with use of the traps baited with ethanol/methanol (1:1), treatment; ii) without use of traps (control). For comparison of results, two factors were considered: damaged fruits (damage by H. hampei) and infested (H. hampei inside of fruits). It was observed higher levels of damaged fruits per plants in the control area compared to the area where traps were used. The density of the pest population per plants found on infested fruits was also higher in the control area compared to the trapping area. These results suggest that traps baited with ethanol/methanol (1:1) are an effective alternative for population control of pest also in the coffee plantations in Rondônia, where there is no such management with this tool. Use of the baited traps to monitor the insect accurately revealed that the flight stimulus of the colonizing females is influenced by values of the environmental variables. According to the results, colonizing females are more active in the afternoon. Therefore, in order to achieve more efficient control of H. hampei, the best time to apply control agents is between 2:00 pm and 6:00 pm.

Mapping of Ice Storage Processes on the Moon with Time-dependent Temperatures

Abstract Lunar cold traps are defined by extremely low time-integrated sublimation loss, so that water ice is expected to accumulate in them. Due to the strong dependence of the sublimation rate on temperature, they have heretofore been delineated by the peak rather than the time-averaged sublimation rate. Here, time-averaged sublimation rates are calculated for the south polar region of the Moon based on 11 yr of Diviner surface temperature measurements. Data for each spatial pixel are binned according to subsolar (diurnal) and ecliptic (seasonal) longitude. Frequency-domain filtering of temperature time series is applied to interpolate and smooth the data set. The cold trap area is 17,000 km2 from 80°S to the south pole, about 24% larger than defined by peak temperature. In addition, subsurface ice stability is mapped based on solutions of the heat equation with Diviner surface temperatures as the upper boundary condition. Even a thin layer of dust reduces the sublimation loss dramatically. A third potential mechanism for ice storage, vapor pumping by temperature cycles, is also mapped, based on a model for the time-variable population of adsorbed water molecules on the lunar surface. The area of significant pumping is estimated to be 96,000 km2 poleward of 80°S. In summary, a new processing technique has been developed that exploits information about the time variability of lunar surface temperatures measured by Diviner, and it results in new maps for the geographic distribution of potential water-ice deposits in the south polar region of the Moon.

A field test of unconventional camera trap distance sampling to estimate abundance of marmot populations

The increasing use of remote motion‐sensitive photography recently led to an extension of distance sampling (DS) to accommodate camera trap data. Camera trap distance sampling (CTDS) has been proposed as a promising tool to estimate animal abundance, if temporally limited availability for detection is accounted for. However, the performance of CTDS in different field situations, and its reliability when single still images are used instead of videos or bursts of images remain untested. We used Alpine marmots Marmota marmota in the Stelvio National Park (Italy) to address three aims: 1) compare estimates of availability bias‐corrected CTDS when using single still images with different set‐ups to define sampling effort. For the ‘user‐manual' set‐up we used values of θ [angle of view] and t∗ [recovery time, i.e. the shortest interval at which an animal can be detected] specified by the camera user manual. For the ‘empirical' set‐up we estimated θ and t∗ empirically. 2) Compare estimates of CTDS and line DS, both corrected for availability bias based on marmot behavior. 3) Compare estimates of CTDS corrected for availability bias with estimates obtained with capture–mark–recapture (CMR), accounting for the effective trapped area. Our results suggest that: 1) CTDS with ‘user‐manual' set‐up underestimated population size compared to the ‘empirical' set‐up; 2) ‘empirical’ CTDS estimates were similar to those of line DS, but CTDS had lower precision; 3) availability bias‐corrected CTDS underestimated abundance compared to CMR. Assessing camera settings empirically is crucial to reduce bias in CTDS estimators when single still images are used. Videos should be preferred as they allow choosing predefined snapshot moments and do not rely on settings that cannot be changed. Overall, our results support the use of CTDS as an alternative to DS, although proper availability‐bias corrections and many cameras are needed to ensure accuracy and acceptable precision.

Bounds on Absolute Gypsy Moth (Lymantria dispar dispar) (Lepidoptera: Erebidae) Population Density as Derived from Counts in Single Milk Carton Traps.

Estimates of absolute pest population density are critical to pest management programs but have been difficult to obtain from capture numbers in pheromone-baited monitoring traps. In this paper, we establish a novel predictive relationship for a probability (spTfer(r)) of catching a male located at a distance r from the trap with a plume reach D.

Mass trapping is a viable alternative to insecticides for management of Anastrepha fraterculus (Diptera: Tephritidae) in apple orchards in Brazil

We evaluated a new integrated pest-management system for Anastrepha fraterculus (Wiedemann, 1830), the main insect pest of apple crops in Brazil. Our strategy combined mass trapping and application of toxic baits in crop systems without (Area 1) and with (Area 3) anti-hail netting. The treatments were compared with the conventional management (applications of toxic baits and insecticides as cover sprays) in two areas without (Area 2) and with (Area 4) anti-hail netting. The study was conducted for two consecutive years (2017–2018 and 2018–2019 seasons). In areas with mass trapping (Area 1 and Area 3), 120 PET traps (600 mL), baited with 300 mL of CeraTrap® hydrolyzed protein, were used per hectare. Fewer A. fraterculus adults were caught in crop systems without anti-hail netting using McPhail monitoring traps in Area 1 (mass trapping) than under conventional management (Area 2). The infestation of A. fraterculus was similar in areas with anti-hail netting with mass trapping (A3) and under conventional management (A4). In the 2017–2018 season, the areas with mass trapping (A1 and A3) had fewer damaged fruits (%) either without (0.4%) and with (0.7%) anti-hail netting than in the areas with conventional management (A2 and A4) without (1.7%) and with (0.8%) anti-hail netting. However, in the 2018–2019 season, fruit damage was similar in all areas studied. Mass trapping combined with the use of toxic baits can be an alternative to the conventional management of A. fraterculus.

Abruptly autofocusing properties of the chirped circular Airy Gaussian vortex beams

We study the autofocusing properties of the chirped circular Airy Gaussian vortex beams (CCAiGVBs) numerically. The evolutions of the intensity and the gradient force of the CCAiGVBs are investigated in this paper. Results show that the CCAiGVBs have two trapped areas where the gradient force vectors joint at the transverse planes. The chirps can greatly modulate the intensity distribution of the hollow portion aroused from the vortex at the focal plane. The focal position, the focal depth, the focal intensity and the focal light spot of the CCAiGVBs can be greatly affected by the chirped factors c1 and c2, the distribution factor b and the topological charge m. We can adjust the intensity distribution and the gradient force distribution especially on the focal position of the CCAiGVBs through choosing an appropriate value of the chirped factors, the distribution factor and the topological charge to meet the actual usage accordingly.

'Candidatus Mycoplasma haemoalbiventris', a novel hemoplasma species in white-eared opossums (Didelphis albiventris) from Brazil.

Opossums of the genus Didelphis are considered synanthropic animals due to their close contact with human beings. Previously, two species of hemotropic mycoplasmas (hemoplasmas) have been detected in opossums: 'Candidatus Mycoplasma haemodidelphidis' in the North American opossum (Didelphis virginiana) and a potentially novel hemotropic Mycoplasma sp. in the white-eared opossums (Didelphis albiventris) from Brazil. Accordingly, the aims of this study were as follows: (a) to determine the prevalence of hemotropic Mycoplasma spp. in free-ranging opossums, (b) to characterize molecularly the hemotropic Mycoplasma sp. infecting opossums and (c) to determine factors associated with hemoplasma infection in opossums from Canoinhas municipality, Santa Catarina State, southern Brazil. For this purpose, 50 white-eared opossums (33 captured and 17 road-killed animals) were evaluated by a pan-hemoplasma PCR assay based on 16S rRNA. Six out of 50 (12%; 95% CI: 5.6%-23.8%) opossums were infested by Ctenocephalides felis fleas. Twenty out of 50 (40%; 95% CI: 26.41%-54.82%) opossums tested positive for hemotropic Mycoplasma sp. by PCR. Sequencing and phylogenetic analysis of the 16S and 23S rRNA gene fragments confirmed that animals were infected by a potentially novel hemotropic Mycoplasma sp. previously reported in white-eared opossums from Brazil. No significant association was found between gender (p=.7759), trap area (p=.0887) or presence of fleas (p=.3811) and positivity for hemoplasmas. The potentially novel hemoplasma species seems to be highly prevalent in white-eared opossums from the states of Paraná, Santa Catarina and Mato Grosso do Sul. Based on the phylogenetic analyses of the 16S rRNA and 23S rRNA genes along with epidemiological data, the name 'Candidatus Mycoplasma haemoalbiventris' is proposed for this novel organism.

OPTIMASI PENGGUNAAN SEDIMENT TRAP PADA ALUR PELAYARAN BARAT SURABAYA MENGGUNAKAN PEMODELAN TRANSPOR SEDIMEN (STUDI KASUS: ALUR PELAYARAN BARAT SURABAYA, JAWA TIMUR)

Tanjung Perak Port is one of the largest ports in Indonesia that is quite strategic for economic development and sea transportation. The handling of shipping lanes is needed so that ship traffic remains stable. The research location in Alur Pelayaran Barat Surabaya with 3 different conditions namely Pre-Survey, Post-Survey condition 1 has a sediment trap and Post-Survey condition 2 has no sediment trap. Research uses 3D modeling to see hydrodynamic activity. The results of modeling are current patterns, which will influence the pattern of sediment distribution in the study area. The model is formed based on the parameters of tides, river discharge, and wind in the study area. Tidal Pre-Survey has a value of RMSE and MAE of 0.0307 meters and 0.0244 meters with a current of 0.3 m/s. Post-Survey condition 1 has a value of 0.0336 meters and 0.0276 meters with a current of 0.2 m/s. Post-Survey condition 2 has a value of 0.0563 meters and 0.0289 meters with a current of 0.4 m/s. The pattern of sediment distribution between Post-Survey conditions 1 and condition 2 has the same dominant value starting from -0.005 meters to 0.0175 meters. Maximum value of condition 1 is 0.072 meters while condition 2 is 0.062 meters in sediment trap area. Even though condition 1 has a maximum value greater than condition 2, it occurs at just a few points.