scholarly journals An Electrostatic Nursery Shelter for Raising Pest and Pathogen Free Tomato Seedlings in an Open-Window Greenhouse Environment

2016 ◽  
Vol 8 (4) ◽  
pp. 13 ◽  
Author(s):  
Yoshihiro Takikawa ◽  
Yoshinori Matsuda ◽  
Teruo Nonomura ◽  
Koji Kakutani ◽  
Kiyotsugu Okada ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Fungal Pathogens ◽  
Frankliniella Occidentalis ◽  
Electrostatic Force ◽  
Western Flower Thrips ◽  
Leaf Miner ◽  
Continuous Exposure ◽  
Oidium Neolycopersici ◽  
Liriomyza Sativae

<p>The electrostatic nursery shelter reported in this work was a transparent film-covered rectangular box with three electric field screens on each of the long sides of the box. This arrangement prevents flying pests and airborne fungal pathogens from entering the nursery space. Insulated conducting wires (ICWs) were used as electrodes to create electric fields. The ICWs were arrayed in parallel, and linked to direct-current voltage sources. The ICW layers were negatively or positively charged with equal voltages to form dipoles; i.e., ICW(–) and ICW(+). The electric field screen consisted of three layers of the ICWs; i.e., an ICW(–) layer on either side of an ICW(+) layer. Four species of major tomato pests were used in a blowing assay: whiteflies (<em>Bemisia tabaci</em>), western flower thrips (<em>Frankliniella occidentalis</em>), green peach aphids (<em>Myzus persicae</em>) and tomato leaf miner flies (<em>Liriomyza sativae</em>). The ICWs were located to capture test pests that were mechanically blown into the electric-field screen. The electrostatic force to capture the insects was directly proportional to the applied voltage, and at voltages of 1.2 kV or greater, the screen exerted sufficient force to capture all of the test pests. An assay in a pest-infested greenhouse revealed that the ICWs captured all the pests that approached the screen, and the plants within the shelter remained pest-free. In addition, we show that the electric-field-screened shelter remained spore-free in the presence of continuous exposure to the conidia of tomato powdery mildew (<em>Oidium neolycopersici</em>).</p>

scholarly journals Developing a Phototactic Electrostatic Insect Trap Targeting Whiteflies, Leafminers, and Thrips in Greenhouses

Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 960
Author(s):  
Yoshihiro Takikawa ◽  
Teruo Nonomura ◽  
Takahiro Sonoda ◽  
Yoshinori Matsuda
Keyword(s):  
Electric Field ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Dielectric Polarization ◽  
Liriomyza Sativae ◽  
Flower Thrips ◽  
Insect Trap ◽  
Positive Voltage ◽  
Filling Water ◽  
Oppositely Charged

Our aim was to develop an electrostatic apparatus to lure and capture silverleaf whiteflies (Bemisia tabaci), vegetable leafminers (Liriomyza sativae), and western flower thrips (Frankliniella occidentalis) that invade tomato greenhouses. A double-charged dipolar electric field producer (DD-EFP) was constructed by filling water in two identical transparent soft polyvinyl chloride tubes arrayed in parallel with fixed separation, and then, inserting the probes of grounded negative and positive voltage generators into the water of the two tubes to generate negatively and positively charged waters, respectively. These charged waters electrified the outer surfaces of the opposite tubes via dielectric polarization. An electric field formed between the oppositely charged tubes. To lure these phototactic insects, the water was colored yellow using watercolor paste, then introduced into the transparent insulator tubes to construct the yellow-colored DD-EFP. This apparatus lured insects in a manner similar to commercially available yellow sticky traps. The yellow-colored DD-EFP was easily placed as a movable upright screen along the plants, such that invading pests were preferentially attracted to the trap before reaching the plants. Furthermore, pests settling on the plants were attracted to the apparatus, which used a plant-tapping method to drive them off the plants. Our study provided an experimental basis for developing an electrostatic device to attract and capture insects that enter greenhouses.

scholarly journals Electrostatic forces alter particle size distributions in atmospheric dust

2020 ◽  
Vol 20 (5) ◽  
pp. 3181-3190 ◽  
Author(s):  
Joseph R. Toth III ◽  
Siddharth Rajupet ◽  
Henry Squire ◽  
Blaire Volbers ◽  
Jùn Zhou ◽  
...  
Keyword(s):  
Electric Field ◽  
Size Distribution ◽  
Long Range ◽  
Electric Fields ◽  
Electrostatic Force ◽  
Small Scale ◽  
Size Distributions ◽  
Electrostatic Forces ◽  
Atmospheric Dust ◽  
Airborne Dust

Abstract. Large amounts of dust are lofted into the atmosphere from arid regions of the world before being transported up to thousands of kilometers. This atmospheric dust interacts with solar radiation and causes changes in the climate, with larger-sized particles having a heating effect, and smaller-sized particles having a cooling effect. Previous studies on the long-range transport of dust have found larger particles than expected, without a model to explain their transport. Here, we investigate the effect of electric fields on lofted airborne dust by blowing sand through a vertically oriented electric field, and characterizing the size distribution as a function of height. We also model this system, considering the gravitational, drag, and electrostatic forces on particles, to understand the effects of the electric field. Our results indicate that electric fields keep particles suspended at higher elevations and enrich the concentration of larger particles at higher elevations. We extend our model from the small-scale system to long-range atmospheric dust transport to develop insights into the effects of electric fields on size distributions of lofted dust in the atmosphere. We show that the presence of electric fields and the resulting electrostatic force on charged particles can help explain the transport of unexpectedly large particles and cause the size distribution to become more uniform as a function of elevation. Thus, our experimental and modeling results indicate that electrostatic forces may in some cases be relevant regarding the effect of atmospheric dust on the climate.

scholarly journals Electrostatic forces alter particle size distributions in atmospheric dust

2019 ◽  
Author(s):  
Joseph R. Toth III ◽  
Siddharth Rajupet ◽  
Henry Squire ◽  
Blaire Volbers ◽  
Jùn Zhou ◽  
...  
Keyword(s):  
Electric Field ◽  
Size Distribution ◽  
Long Range ◽  
Electric Fields ◽  
Electrostatic Force ◽  
Small Scale ◽  
Size Distributions ◽  
Electrostatic Forces ◽  
Atmospheric Dust ◽  
Airborne Dust

Abstract. Large amounts of dust are lofted into the atmosphere from arid regions of the world before being transported up to thousands of kilometers. This atmospheric dust interacts with solar radiation causing changes in the climate, with larger-sized particles having a heating effect, and smaller-sized particles having a cooling effect. Previous studies on the long-range transport of dust have found larger particles than expected, without a model to explain their transport. Here, we investigate the effect of electric fields on lofted airborne dust by blowing sand through a vertically-oriented electric field, and characterizing the size distribution as a function of height. We also model this system, considering the gravitational, drag, and electrostatic forces on particles, to understand the effects of the electric field. Our results indicate that electric fields keep particles suspended at higher elevations and enrich the concentration of larger particles at higher elevations. We extend our model from the small-scale system to long-range atmospheric dust transport to develop insights on the effects of electric fields on size distributions of lofted dust in the atmosphere. We show that the presence of electric fields and the resulting electrostatic force on particles can help explain the transport of unexpectedly larger particles and cause the size distribution to become more uniform as a function of elevation. Thus, our experimental and modelling results indicate that electrostatic forces should be considered when determining the effect of atmospheric dust on the climate.

scholarly journals Reinterpretation of Electric Field with Quantum Fluctuations: The Mechanism of Electrostatic Force of Attraction and Repulsion Between Two Point Charges

2020 ◽  
pp. 28-33
Author(s):  
C. G. Sim
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Vacuum Polarization ◽  
Quantum Fluctuation ◽  
Casimir Effect ◽  
Electrostatic Force ◽  
Quantum Fluctuations ◽  
Repulsive Force ◽  
Fluctuation Energy ◽  
Virtual Pairs

Vacuum polarization rearranges virtual  pairs. This causes the virtual  pairs to rigidify in vacuum, reducing the quantum fluctuation energy. The quantum fluctuation energy is a fundamental force of vacuum, as evidenced by the Casimir effect. The change in quantum fluctuation energy was simulated in the superposition of the electric fields. The results show that the increase and decrease of the quantum fluctuation energy between the two point charges is related to the repulsive force and attraction in Coulomb's law.

scholarly journals Exclusion of Flying Insect Pests From a Plastic Hoop Greenhouse by a Bamboo Blind-Type Electric Field Screen

2020 ◽  
Vol 12 (2) ◽  
pp. 50
Author(s):  
Yoshihiro Takikawa ◽  
Yoshinori Matsuda ◽  
Teruo Nonomura ◽  
Koji Kakutani ◽  
Shin-ichi Kusakari ◽  
...  
Keyword(s):  
Electric Field ◽  
Insect Pests ◽  
Western Flower Thrips ◽  
Leaf Miner ◽  
Tomato Plants ◽  
Voltage Range ◽  
Flower Thrips ◽  
Positive Voltage ◽  
Tomato Leaf Miner ◽  
Direct Current Voltage

The present study describes an economically efficient method for controlling viruliferous whiteflies in a plastic hoop greenhouse, using a bamboo blind-type electric field screen (Bb-EFS) to create a pest-free space. The Bb-EFS had a layer of insulated round iron conductor bars (IBs) and two electrostatic direct current voltage generators that supplied negative or positive voltage to the IBs. The IBs were placed parallel at 4-mm intervals and were connected alternately to a negative or positive voltage generator. Adult test insects (whiteflies, western flower thrips, and tomato leaf miner flies) were blown at up to 5 m/s towards the IBs to identify the voltage range that would capture all the test insects. The results showed that a force &ge; 5.0 kV was strong enough for the IBs to capture all test insects, despite a wind speed of 5 m/s. The Bb-EFS was practical for a greenhouse that experienced frequent invasion by numerous viruliferous whiteflies. Seedlings grew normally inside the Bb-EFS-installed greenhouse. As a supplementary method, an electrostatic insect sweeper and electrostatic flying insect catcher were used to trap whiteflies that avoided the Bb-EFS. Both pieces of apparatus were convenient and easy to operate onsite in a greenhouse environment and were used to trap whiteflies residing on tomato plants or flying inside the greenhouse during daily plant care. These methods controlled the whitefly population to negligible levels, and nearly all tomato plants produced normal fruits.

Effect of Pesticide Mixtures on the Survival of the Predatory Mite Neoseiulus cucumeris (Acarina: Phytoseiidae)

2007 ◽  
Vol 42 (3) ◽  
pp. 311-319 ◽  
Author(s):  
Heather E. Lash ◽  
Daniel F. Warnock ◽  
Raymond A. Cloyd
Keyword(s):  
Fungal Pathogens ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Predatory Mite ◽  
Water Control ◽  
Neoseiulus Cucumeris ◽  
Thiophanate Methyl ◽  
Pesticide Mixtures ◽  
Control Programs ◽  
Flower Thrips

This study was conducted to determine the effect of 2 insecticides/miticides, spinosad and abamectin, and 2 fungicides, thiophanate-methyl and fenhexamid, when applied alone or mixed in all combinations, on the survival of Neoseiulus cucumeris (Oudemans). Neoseiulus cucumeris is a predatory mite utilized in greenhouses for managing western flower thrips, Frankliniella occidentalis Pergande. The deutonymph and adult stages of N. cucumeris were directly exposed to the pesticide treatments or a water control. Overall, the deutonymphs were more susceptible to the pesticide treatments, based on percent survival 24 h after treatment, than the adults. Five of the 7 pesticide mixtures containing spinosad and 4 of the 7 mixtures containing abamectin resulted in deutonymph mortality values between 50 and 69%. Thiophanate-methyl alone and in combination with either spinosad or abamectin resulted in &gt;35% mortality of the deutonymphs. Based on the results of this study, spinosad and abamectin, when used alone or in mixture with thiophanate-methyl will reduce N. cucumeris populations by killing the deutonymphs. This information is important to greenhouse managers who want to use pesticide mixtures to manage arthropod pests and fungal pathogens without disrupting biological control programs for western flower thrips.

scholarly journals Soil Surface-Trapping of Tomato Leaf-Miner Flies Emerging from Underground Pupae with a Simple Electrostatic Cover of Seedbeds in a Greenhouse

Insects ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 878
Author(s):  
Teruo Nonomura ◽  
Hideyoshi Toyoda
Keyword(s):  
Electric Field ◽  
Soil Surface ◽  
Tomato Leaf ◽  
Leaf Miner ◽  
Leaf Miners ◽  
Liriomyza Sativae ◽  
Promising Tool ◽  
Tomato Leaf Miner ◽  
Greenhouse Assay ◽  
Greenhouse Tomatoes

In the present study, an electrostatic apparatus for trapping adult tomato leaf miner flies (Liriomyza sativae) emerging from underground pupae at the surface of a seedbed in an organic greenhouse was developed. The apparatus consisted of insulated iron rods arranged in parallel at set intervals and linked to a voltage generator, which supplied a negative charge to the rods, as well as non-insulated grounded iron rods with the same configuration. The two layers of insulated and non-insulated iron rods were arrayed in parallel to form a static electric field between the layers. The electric field created a strong attractive force capable of capturing flies that entered the field. In a greenhouse assay, the apparatus was placed horizontally above a seedbed in a greenhouse and surveyed for its ability to capture adult flies emerging from pupae that were introduced onto the seedbed beneath the apparatus. The results revealed that the apparatus effectively trapped all adult flies that emerged from the pupae and that it functioned stably while continuously operated during the entire period of the experiment. Thus, our novel apparatus is a promising tool for the physical control of adult tomato leaf miners in the insecticide-independent cultivation of greenhouse tomatoes.

Tuning the Electric Field Response of MOFs by Rotatable Dipolar Linkers

2019 ◽  
Author(s):  
Johannes P. Dürholt ◽  
Babak Farhadi Jahromi ◽  
Rochus Schmid
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Structural Changes ◽  
Dielectric Behavior ◽  
Two Dimensions ◽  
Dielectric Constants ◽  
Electric Response ◽  
Dipole Strength ◽  
Metal Organic ◽  
Dynamics Simulations

Recently the possibility of using electric fields as a further stimulus to trigger structural changes in metal-organic frameworks (MOFs) has been investigated. In general, rotatable groups or other types of mechanical motion can be driven by electric fields. In this study we demonstrate how the electric response of MOFs can be tuned by adding rotatable dipolar linkers, generating a material that exhibits paralectric behavior in two dimensions and dielectric behavior in one dimension. The suitability of four different methods to compute the relative permittivity κ by means of molecular dynamics simulations was validated. The dependency of the permittivity on temperature T and dipole strength μ was determined. It was found that the herein investigated systems exhibit a high degree of tunability and substantially larger dielectric constants as expected for MOFs in general. The temperature dependency of κ obeys the Curie-Weiss law. In addition, the influence of dipolar linkers on the electric field induced breathing behavior was investigated. With increasing dipole moment, lower field strength are required to trigger the contraction. These investigations set the stage for an application of such systems as dielectric sensors, order-disorder ferroelectrics or any scenario where movable dipolar fragments respond to external electric fields.

scholarly journals Meta-Deflectors Made of Dielectric Nanohole Arrays with Anti-Damage Potential

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 107
Author(s):  
Haichao Yu ◽  
Feng Tang ◽  
Jingjun Wu ◽  
Zao Yi ◽  
Xin Ye ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Laser Cutting ◽  
High Complexity ◽  
Damage Potential ◽  
Optical Components ◽  
Nanohole Arrays ◽  
Intense Light ◽  
Polarization Of Light ◽  
Air Hole

In intense-light systems, the traditional discrete optical components lead to high complexity and high cost. Metasurfaces, which have received increasing attention due to the ability to locally manipulate the amplitude, phase, and polarization of light, are promising for addressing this issue. In the study, a metasurface-based reflective deflector is investigated which is composed of silicon nanohole arrays that confine the strongest electric field in the air zone. Subsequently, the in-air electric field does not interact with the silicon material directly, attenuating the optothermal effect that causes laser damage. The highest reflectance of nanoholes can be above 99% while the strongest electric fields are tuned into the air zone. One presentative deflector is designed based on these nanoholes with in-air-hole field confinement and anti-damage potential. The 1st order of the meta-deflector has the highest reflectance of 55.74%, and the reflectance sum of all the orders of the meta-deflector is 92.38%. The optothermal simulations show that the meta-deflector can theoretically handle a maximum laser density of 0.24 W/µm2. The study provides an approach to improving the anti-damage property of the reflective phase-control metasurfaces for intense-light systems, which can be exploited in many applications, such as laser scalpels, laser cutting devices, etc.

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