Electrostatic force distribution on an electrodynamic screen

Sayyah, Arash; Horenstein, Mark N.; Mazumder, Malay K.; Ahmadi, Goodarz

doi:10.1016/j.elstat.2016.02.004

Cited by 55 publications

(34 citation statements)

References 29 publications

(33 reference statements)

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“…This technology will also solve the problem for solar farms placed in deserts where accumulated dust and sand block the sun light. Experiments performed by MIT have shown that one dust storm can cut power production by 40% …”

Section: Light‐responsive Liquid Crystal Networkmentioning

confidence: 99%

Surface Dynamics at Photoactive Liquid Crystal Polymer Networks

Liu

2019

Advanced Optical Materials

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creating insulation under cold conditions and emitting evaporable liquid when it is warm. [1][2][3] Peacock feathers, wings of certain butterflies, and plants exhibit color by means of structural color to communicate attraction or, inversely, repulsion. Often, the colors originate from periodic structures on or under a surface, thus benefiting from the interplay of light and diffractive effects.A surface is the outermost layer of matter and therefore is primarily perceived by humans upon touch or vision. Surfaces provide perceptible information by not only shape, color, and/or reflective properties but also how the matter feels upon touch, e.g., smooth or rough. Welldocumented static structures have been reported for haptic applications. [4] Studies have suggested that humans can distinguish changes in topographical dimensions down to nanometers. [5] Additionally, a surface is the first contact between objects of matter, either of the same object or that of another origin. Surfaces facilitate man-machine interactions, [6] either by touch (smooth, rough, heat conductive, etc.) or by vision (scattering, specular reflection, printed information, etc.). [7][8][9] In relation to this function, tribological properties such as friction, stick, and adhesion coefficients also find application in the field of haptics, where robotic manipulation is of importance. In contrast to nature, the surface structures in modern man-made technology are often still static. Mimicking the lotus flower, surfaces with artificially formed micrometer-sized structures that are produced by lithography or micromachining have been made, and they indeed show improved cleaning under rainy conditions. However, one expands the surface function when these structures are made dynamic, rather than static, for example, the surface would be able to remove dirt under dry conditions, as well. In the case of topographies for haptic use, man's sensitivity could be enhanced when the corrugations are moving with a frequency tuned to the maximum sensitivity of humans. However, only a few publications have described dynamic structures to enhance human-surface interactions, which could even help visually disabled people. Moreover, in an advanced technology such as microfluidics, the low Reynolds number prohibits turbulent mixing of fluid components. Mixing can be induced by surface topographical structures in the microchannels to increase the contact area and the contact time between the reagents. The microfluidic functionality would be enhanced if the topography of its inner walls could be switched in a dynamic way, e.g., to decide on the exact location and time that switching The field of advanced and responsive soft materials is at the edge of a new era. After several decades during which liquid crystals generated new functions for information displays and could solve many problems in emerging fields such as (tele)communications, this material system is being utilized to reach out to completely new application fields with functions that can take over biologica...

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Section: Light‐responsive Liquid Crystal Networkmentioning

confidence: 99%

Surface Dynamics at Photoactive Liquid Crystal Polymer Networks

Liu

2019

Advanced Optical Materials

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“…Humid dust has proved extremely difficult to remove due to the presence of capillary forces between particles mutually and between the particles and the surface . Figure b(2)–(4) shows humid sand grains obtained by adding 10 wt% water.…”

mentioning

confidence: 99%

Oscillating Chiral‐Nematic Fingerprints Wipe Away Dust

2018

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access to water is often limited and waterbased self-cleaning approaches are not applicable. We report here a new concept of a dry self-cleaning method without the aid of water. This will solve a problem for solar farms placed in deserts where accumulated dust and sand at the surfaces of the photovoltaic cells block the sun light, which might cut power production as a result of a sand storm by 40%. [12] For reference, contaminated solar panels in solar farms are still removed from deposited dust by manually brushing. In addition, dust mitigating technologies may be used to protect any mechanical/optical/electric systems that carry out Lunar/Mars missions against dust hazards.[13] The waterfree self-cleaning philosophy we propose here is based on an orchestrated change of the surface topography. The induced vibrations mechanically transport dusts and debris to the edges of the surface, eventually supported by gravity when the surface is tilted. In a previous publication, we reported on homeotropic nematic liquid crystal network (LCN) which we could bring into a volumetric vibration by a high-frequency AC electric field. [14] The dynamic topographies were irregular and rather small, in the order of 100 nm. In order to create larger deformations, we focus here on a chiralnematic LCN that is brought in the so-called fingerprint mode with periodically alternating planar and homeotropic molecular alignment. The electrically induced change of the order parameter, with periodic alternating contraction and expansion, is anticipated to enhance the surface deformation to dimensions capable to transport sand grains. In addition, the topographic periodicity will be determined by the pitch of the molecular helix rather than by electrode spacing.The particle-rejecting coating is made by in situ photopolymerization of a mixture of chiral reactive mesogens that forms a crosslinked LCN on top of interdigitated electrodes (IDE). We chose for the IDE as it provides an in-plane electrical field while the LC coating will form an electrical isolating shield protecting potential users. By controlling the surface conditions of this IDE substrate prior to polymerization as described in Experimental Section the rod-like mesogens in the LCN adapted a helicoidal organization with the helix axes parallel to the surface as schematically shown in Figure 1a. The helix axes take a worm-like configuration (Figure 1b) also known as fingerprint texture. The black area in Figure 1b corresponds to the molecules that are homeotropically aligned while the planar orientation is optically birefringent showing blue color. More fingerprints patterns are shown in Figures S1 and S2 of the Supporting Information.The underlying deformation mechanism is to decrease the LCN order parameter and bringing the LCN into oscillation by a lateral This work presents an approach to create mechanical undulations at a solid organic coating surface under the influence of an electric field. The coating is fabricated through polymerization of chiral reactive mesogens aligned ...

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“…After 3 years of study (2017-2020), Mazumder et al [160] reported that the dust removal efficiency and reflectivity restauration of EDS are both high and that EDS can operate under various temperatures and relative humidity; the authors concluded after an economic analysis that EDS technology is on a commercial level. However, other studies confirmed EDS to be greatly affected by humidity [161,162], Javed and Guo [163] reported a decreasing dust removal efficiency from 22% at RH of 10% to 9% at RH of 80%, and suggested to increase the frequency of EDS device activation (hourly or bi-hourly) in order to improve its cleaning efficiency.…”

Section: Electrodynamic Screens "Eds"mentioning

confidence: 99%

Dust impact on concentrated solar power: A review

Zereg

Gama

Aksas³

et al. 2021

Environmental Engineering Research

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Many sites with high solar radiation face high dust loads that reduce energy generation by concentrated solar power plants. This review presents the attenuative impacts of atmospheric aerosols, as well as reflectivity losses due to soiling of solar reflectors, by covering both experimental investigations and numerical studies; along with presenting the theoretical background. The chemical nature of aerosols, and the physics of soiling and atmospheric extinction phenomena (scattering and absorption) are also reviewed. Suspended particles like aerosols result in atmospheric extinction of the solar radiation that reaches the concentrators, and the deposition of these particles on the solar reflectors provokes decreases up to 80% in their reflectivity, and thus enhances the cumulus of optical losses and the reduction of energy production. Even though dust affects both CSP and photovoltaics, CSP technologies suffer more losses. The impact of dust should be particularly considered during the planning phase of solar thermal plants, since its consequent reduction in energy output can be severe. While there have been multiple papers to review dust-related problems for PV, the present paper is the first literature review dedicated to the impact of soiling on concentrated solar power.

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Electrostatic force distribution on an electrodynamic screen

Cited by 55 publications

References 29 publications

Surface Dynamics at Photoactive Liquid Crystal Polymer Networks

Surface Dynamics at Photoactive Liquid Crystal Polymer Networks

Oscillating Chiral‐Nematic Fingerprints Wipe Away Dust

Dust impact on concentrated solar power: A review

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