Effect Of Electrostatic Charge Research Articles

A human pilot study on positive electrostatic charge effects in solid tumors of the late-stage metastatic patients.

Correlative interactions between electrical charges and cancer cells involve important unknown factors in cancer diagnosis and treatment. We previously reported the intrinsic suppressive effects of pure positive electrostatic charges (PEC) on the proliferation and metabolism of invasive cancer cells without any effect on normal cells in cell lines and animal models. The proposed mechanism was the suppression of pro-caspases 3 and 9 with an increase in Bax/Bcl2 ratio in exposed malignant cells and perturbation induced in the KRAS pathway of malignant cells by electrostatic charges due to the phosphate molecule electrostatic charge as the trigger of the pathway. This study aimed to examine PECs as a complementary treatment for patients with different types of solid metastatic tumors, who showed resistance to chemotherapy and radiotherapy. In this study, solid metastatic tumors of the end-stage patients (n = 41) with various types of cancers were locally exposed to PEC for at least one course of 12 days. The patient's signs and symptoms, the changes in their tumor size, and serum markers were followed up from 30 days before positive electrostatic charge treating (PECT) until 6 months after the study. Entirely, 36 patients completed the related follow-ups. Significant reduction in tumor sizes and cancer-associated enzymes as well as improvement in cancer-related signs and symptoms and patients' lifestyles, without any side effects on other tissues or metabolisms of the body, were observed in more than 80% of the candidates. PECT induced significant cancer remission in combination with other therapies. Therefore, this non-ionizing radiation would be a beneficial complementary therapy, with no observable side effects of ionizing radiotherapy, such as post-radiation inflammation.

In situ electron-beam-induced mechanical loading and fracture of suspended strained silicon nanowires

The mechanical properties characterization of silicon nanowires is generally performed by tensile nanomechanical loading tests with in situ strain quantification. While the strain is characterized by electron beam (e-beam) microscopy techniques, the understanding of the sample-electron interaction is essential to guarantee artifact-free measurements. In this work, we investigated suspended strained silicon nanowires under electron beam exposure in a scanning electron microscope (SEM). The fabricated nanowires had their initial stress profile characterized by Raman spectroscopy and finite element method simulations. Then, the sample was exposed to an e-beam where we observed a gradual electrical charging of the sample, verified by the image drift, and down deflection of the suspended nanowire caused by electrostatic forces. These additional stresses induced the mechanical fracture of the nanowires in the corner region due to accumulated stress. These results ascribe electrostatic mechanical loading concerns that may generate undesirable additional stresses in nanomechanical tests performed in SEM, demonstrating the importance of proper sample preparation to avoid electrostatic charging effects. Here, we propose a simple and effective method for imposing the structures under an impinging electron beam at an equipotential, which mitigates the charging effects acting on the nanowire.

Numerical investigation of powder dispersion mechanisms in Turbuhaler and the contact electrification effect

Powder dispersion in dry powder inhalers (DPI) is affected by factors such as device design and flow rate, but also electrification due to particle–particle/device collisions. This work presented a CFD-DEM study of powder dispersion in Turbuhaler®, aiming to understand the effect of electrostatic charge on the dispersion mechanisms. The device geometry was reconstructed from CT-scan images of commercial Turbuhaler device. Different work functions were applied to the active pharmaceutical ingredient (API) powder and the device wall. Electrostatic charges were accumulated on the API particles due to contact potential difference (CPD) between the particles and the device wall. Results showed that both the chamber and the spiral mouthpiece played an important role in de-agglomeration of powders caused by particle–wall impactions. With increasing flow rates, the performance of the device was improved with higher emitted dose (ED) and fine particle fractions (FPF). The electrostatic charging of the particles was enhanced with higher CPD and higher flow rates, but the electrostatic charging had a minimum effect on powder dispersion and deposition with slight reduction in ED and FPF. In conclusion, the van der Waals force is still the dominant adhesive inter-particle force, and the dispersion efficiency is affected by the flow rate rather than contact electrification of particles. Future work should focus on the effect of highly charged particles emitted from the inhaler on the deposition in the airway.

(Invited) Optical Properties and Active Plasmon Excitations in Nanocrystals and 2D Materials

The control and tuning of the optical properties of materials and the localization of electromagnetic energy are long standing quests for scientists. Not only it allows to design new classes of adaptive devices such as smart windows but also to perform surface enhanced vibrational spectroscopies such a SERS. Behind all these applications, fundamental questions are still debated : what is the role of electron correlation in the optical response ? How to include to contribution of crystal field in the dielectric response of complex system ? How the local electro-magnetic field influence the optical absorption and the SERS activity ?For metallic nanostructured systems, the optical properties are directly related to collective electronic excitation (plasmons) and they depend mainly on the composition, shape and size of the system. Doped semiconductors such as Indium Tin Oxide have been also shown to display active plasmon, i.e., optical excitations that can be controlled by an external stimulus such as static electric potential [1].In 2D materials like graphene, the electrostatic doping is a commonly used to modify the optical response due to the low density of state at the Fermi energy. Moreover, topological corrugation, anisotropy [2], chemical doping [3] and electrostatic coupling in vanderwaals heterostructures plays very specific roles on the optical responses. Graphene nanodots and molecular PAH also supported plasmon excitation and electrochromic behavior.In this presentation, based on numerical simulations, we analyze the optical properties of these compounds and we discuss the influence of electrostatic coupling and charging effects. We emphasized the role of the electron correlation and of the local field in classical, semi-empirical and ab-initio methods.[1] A. Maho et al. Solar Energy Materials and Solar Cells 200 (2019) 110014[2] B. Majerus et al. Phys. Rev. B 98 (2018) 125419[3] F. Joucken et al. Phys. Rev. Mat. 3 (2019) 110301

Null-Result Test for Effect on Weight from Large Electrostatic Charge

We report test results searching for an effect of electrostatic charge on weight. For conducting test objects of mass of order 1 kg, we found no effect on weight, for potentials ranging from 10 V to 200 kV, corresponding to charge states ranging from 10−9 to over 10−5 coulombs, and for both polarities, to within a measurement precision of 2 g. While such a result may not be unexpected, this is the first unipolar, high-voltage, meter-scale, static test for electro-gravitic effects reported in the literature. Our investigation was motivated by the search for possible coupling to a long-range scalar field that could surround the planet, yet go otherwise undetected. The large buoyancy force predicted within the classical Kaluza theory involving a long-range scalar field is falsified by our results, and this appears to be the first such experimental test of the classical Kaluza theory in the weak field regime, where it was otherwise thought identical with known physics. A parameterization is suggested to organize the variety of electro-gravitic experiment designs.

The effect of electrostatic charges on particle-laden duct flows

Abstract

The closed-edge structure of graphite and the effect of electrostatic charging

The properties of graphite, and of few-layer graphene, can be strongly influenced by the edge structure of the graphene planes, but there is still much that we do not understand about the geometry and stability of these edges. We present an experimental and theoretical study of the closed edges of graphite crystals, and of the effect of an electric field on their structure. High-resolution transmission electron microscopy is used to image the edge structure of fresh graphite and of graphite that has been exposed to an electric field, which experiences a separation of the graphene layers. Computer simulations based on density functional theory are used to rationalise and quantify the preference for the formation of multiple concentric loops at the edges. A model is also presented to explain how the application of an electric field leads to the separation of the folded edges.

The effect of electrization on the properties of flowing water-oil emulsion

The electrization of the water-oil mixture is a negative factor, the study of which has so far been neglected. Electrostatic charges generated in the pipelines during oil transportation, are accumulated in oil-water mixture. It essentially changes the corrosion activity of the aqueous phase and enables water-oil emulsion stabilization. The purpose of the study is to determine the effect of electrostatic charges that are generated during oil transportation through pipelines on the stabilization of water-oil emulsions. It is established that the accumulation of electrostatic charges in the oil phase leads to the stabilization of the water-oil emulsion, i.e. to the increase of “water-oil” interphacial tension. It is shown that demulsifiers increase the redistribution of electrostatic charges between aqueous and oil phases. The proposed method preventing the stabilization of emulsion is based on reduction of electrostatic charges redistribution in “water-oil” system by introducing antistatic surfactants.

The Effect of Electrostatic Charge on the Propagation of GPS (L‐band) Signals Through Volcanic Plumes

AbstractRecent field studies have shown that the presence of ash in the atmosphere can produce measurable attenuation of Global Positioning System (GPS) signals (Aranzulla et al., 2013, https://doi.org/10.1007/s10291-012-0294-4; Larson, 2013, https://doi.org/10.1002/grl.50556; Larson et al., 2017, https://doi.org/10.1016/j.jvolgeores.2017.04.005). The ability to detect plumes using GPS is appealing because many active volcanoes are already instrumented with high‐quality receivers. However, analyses using a Ralyeigh approximation have shown that the large attenuations cannot be explained by the scattering and absorption associated with ash or hydrometeors alone. Here, we show that the extinction of GPS signals, which fall into the L‐band of the electromagnetic spectrum, may be exacerbated significantly by excess surface charge on pyroclasts. Indeed, volcanic eruptions are often accompanied by a range of electrostatic processes, leading, in some cases, to spectacular lightning storms. We use a modified Mie scattering model to demonstrate that electrostatic effects can increase the extinction of L‐band radiation by up to an order of magnitude, producing attenuations consistent with those observed in the field. Thus, future work involving GPS as a tool to remotely probe plumes must take into account the electrification of ash in radiative transfer models. Additionally, we propose that the sensitivity of GPS to particle charging may catalyze the development of new techniques to explore electrostatic processes in plumes, especially if GPS measurements are complemented with millimeter‐wave RADAR measurements.

Effect of electrostatic charge of particles on hydrodynamics of gas-solid fluidized beds

The aim of this work was to investigate effect of electrostatic charge of particles on the fluidization hydrodynamics. Behavior of bubbles in beds of polyethylene particles was studied through analysis of pressure fluctuations in the frequency domain. Fluidized beds of uncharged, pre-charged and bed-charged particles were used in the experiments. Results revealed that in the bed of pre-charged particles, compared to uncharged experiments, particle-particle repulsive force increases the bed voidage and reduces equilibrium bubble size while the transition velocity to turbulent fluidization is decreased. In the case of bed-charged particles, at low gas velocities bubble fraction is greater compare to the other cases due to faster bubble coalescence in the presence of particle-wall attractive electrostatic force. Electrostatic charge of bulk increases by increasing the gas velocity. At high gas velocities, the repulsion force between highly charged particles overcomes the particle-wall effect on bubble formation and reduces the bubble size to less than in uncharged experiments. Accumulation of particles near the wall in the bed od bed-charged particles affects the hydrodynamics in two ways: first it accelerates bubble growth via bubble coalescence at low gas velocities, second it limits the bubble growth and reduces the transition velocity to turbulent regime to a value less than for pre-charged particles.

Computational modeling of the electrostatic charge build-up in fluidized beds

Coupled computational fluid dynamics and discrete element method was used to investigate the electrostatic charge build-up in fluidized beds. The charge transfer among particles and particles-wall collision was considered. The repulsive electrostatic force among particles increases the bed voidage and bubble size decreases. The average charge of particles linearly increases with time and the slope of this line increases at higher gas velocities. There is a lack of experimental data on charge transfer and effect of electrostatic charge of particles on the hydrodynamics of fluidized beds and this work provides a first insight into the charge transfer on bubble behaviors.

QCM-D and XPS study of protein adsorption on plasma polymers with sulfonate and phosphonate surface groups.

As some proteins are known to interact with sulfated and phosphated biomolecules such as specific glycosaminoglycans, this study derives from the hypothesis that sulfonate and phosphonate groups on solid polymer surfaces might cause specific interfacial interactions. Such surfaces were prepared by plasma polymerization of heptylamine (HA) and subsequent grafting of sulfonate or phosphonate groups via Michael-type addition of vinylic compounds. Adsorption of the proteins fibrinogen, albumin (HSA) and lysozyme on these functionalised plasma polymer surfaces was studied by XPS and quartz crystal microbalance with dissipation (QCM-D). It was also studied whether pre-adsorption with HSA would lead to a passivated surface against further adsorption of other proteins. XPS confirmed grafting of vinyl sulfonate and vinyl phosphonate onto the amine surface and showed that the proteins adsorbed to saturation at between 1 and 2 h. QCM-D showed rapid and irreversible adsorption of albumin on all three surfaces, while lysozyme could be desorbed with PBS to substantial extents from the sulfonated and phosphonated surfaces but not from the amine surface. Fibrinogen showed rapid initial adsorption followed by slower additional mass gain over hours. Passivation with albumin led to small and largely reversible subsequent adsorption of lysozyme, whereas with fibrinogen partial displacement yielded a mixed layer, regardless of the surface chemistry. Thus, protein adsorption onto these sulfonated and phosphonated surfaces is complex, and not dominated by electrostatic charge effects.

Spin-dependent tunnelling in magnetite nanoparticles

Fe3O4 nanoparticles have been made by a co-precipitation method with an average size of 13 nm. Raman measurements show that there is also a small fraction of maghemite that is not seen in the XRD data. The saturation magnetization is high for this preparation method and the coercive field is low at 300 K. The high field magnetic moment cannot be fitted to a Bloch temperature dependence over the full temperature range, which is likely due to the effect of the Verwey transition at 120 K. Pressed powders shows a magnetoresistance of up to −6.5% at 8 T and 300 K. The magnetoresistance can be fitted to a model where there is a spin-dependent tunnelling between nanoparticles with a spin-disordered shell. The temperature dependence of the resistivity can be attributed to nanoparticle electrostatic charging effects.

Pressure wave attenuation in agas solid fluidized bed: Effects of particles size, density and the electrostatic charge

Simultaneously digital image analysis (DIA) and pressure fluctuation analysis (PFA) have been employed to study the pressure wave attenuation behavior in a gas-solid fluidized bed. The effects of particles size, density, and natural electrostatic charge have been investigated. It was shown that increasing of the particle density leads to an increase in the pressure amplitude but has no effect on the pressure wave attenuation trend. It was also observed that the maximum pressure amplitude is proportional to the mass loaded in the bed above the probe. Increasing the particle size and having electrostatic charge both lead to an increase in the local void fraction of the dense phase which in turn lead to a reduction in the pressure amplitude and increasing the pressure wave decay factor. Thus, the wave attenuation trend can be attributed to the local void fraction of particles in the emulsion phase.

RETRACTED: Development and characterisation of semi-crystalline composite granules: The effect of particle chemistry and the electrostatic charging

Abstract This study investigated the surface of semi-crystalline composite granules produced via a novel mechano-chemical process and assessed the effect of electrostatic charging. Ibuprofen (IBU), a model drug with low solubility and known associated processing challenges was loaded in composite granules to improve its processibility and dissolution rates. Synthetic amorphous mesoporous magnesium alumina metasilicate (MAS) was co-processed with hydrophilic HPMC polymer in the presence of polyethylene glycol 2000 (PEG) and deionised water. The solid state analyses conducted by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) revealed the existence of semi-crystalline IBU in the complex composite structures. Dynamic vapour sorption (DVS) study showed the water sorption and desorption profiles of the manufactured composite granules as well as the effect of water on the solid-state stability of IBU in various formulations. Advanced surface analysis conducted via energy dispersive X-ray (EDS) revealed homogenous distribution of the drug/excipients on the surface of the granules while atomic force microscopy (AFM) complemented the findings. The electrostatic charge analysis showed variable charge property which is affected by the size of the particles/granules. As expected, the in vitro dissolution study showed about 5 fold increase in the release rates of IBU compared to that of the bulk drug. The mechanochemical processing has been demonstrated as an efficient technique to develop semi-crystalline composite granules with enhanced dissolution rates of water insoluble drugs.

Mechanistic and thermodynamic aspects of Cs(I) and Sr(II) interactions with smectite-rich natural clay

Sorption of long-lived fission products Cs(I) and Sr(II) by smectite-rich natural clay, originated from western part of India, has been studied by batch sorption method under varying experimental conditions of pH, ionic strength, metal ion concentration and temperature. Low metal ion concentration of Sr in the experiment was achieved using carrier free 85Sr radiotracer prepared using 85Rb(p,n)85Sr nuclear reaction. Ion-exchange-based modelling of sorption data was carried out to delineate the sorption mechanism of fission products. The clay is under evaluation as an engineered barrier and buffer material for Indian deep-underground geo-repository for disposal of vitrified high-level liquid waste. In modelling of Cs(I) sorption data, two sorption sites were found. One of these sites is selective for Cs(I) with high log K value (7.2 ± 0.2). The affinity pattern for the other site is in conformity with the effect of electrostatic charge of the metal ion in an ion exchange process. Ion exchange in Sr(II) sorption was observed at a single surface site. Affinity of Sr(II) binding to this site (log K = 2.7 ± 0.1) was found to be higher than that observed for Cs(I) (log K = 1.2 ± 0.2). To thermodynamically characterize the sorption sites, sorption of Cs(I) and Sr(II) on clay was carried out over 25–55.5 °C. Significantly different ratio of thermodynamic parameters (enthalpy and entropy values) was obtained for the two sorption sites of Cs(I) while there was negligible temperature effect for Sr(II) exchange at clay.

Effect of particle electrostatic charge on aerosol filtration by a fibrous filter

This study aimed to investigate the influence of the particle charge level on collection efficiency and pressure drop during aerosol filtration in a fiber filter. An Electrostatic Charge Classifier (ECC) measured the charge level of aerosol as a function of the particle diameter. The filter was made of polypropylene; its mass per area was 600g/m2, its diameter was 0.047m, and its thickness was 0.0026m. Phosphate rock was the test dust (density: 3030kg/m3; average Stokes diameter: 3.25μm). The aerosol was dispersed in air by a TSI Venturi type generator, model SSPD 3433. The particle charging was achieved by a corona charger. A relationship between the charge of particles and their diameter was identified. From the filtration results, it was analyzed the effect of the electrostatic charges in the particles on the performance of the filter (collection efficiency and pressure drop). The correlations from the literature did not adequately predict the experimental data behaviour. Thus, we proposed a new expression for the electrophoretic collection mechanism, which was consistent with the experimental results found in this research, as well as of other studies in the literature.

Combined effect of moisture and electrostatic charges on powder flow

It is well known in industrial applications involving powders and granular materials that the relative air humidity and the presence of electrostatic charges influence drastically the material flowing properties. The relative air humidity induces the formation of capillary bridges and modify the grain surface conductivity. The presence of capillary bridges produces cohesive forces. On the other hand, the apparition of electrostatic charges due to the triboelectric effect at the contacts between the grains and at the contacts between the grains and the container produces electrostatic forces. Therefore, in many cases, the powder cohesiveness is the result of the interplay between capillary and electrostatic forces. Unfortunately, the triboelectric effect is still poorly understood, in particular inside a granular material. Moreover, reproducible electrostatic measurements are difficult to perform. We developed an experimental device to measures the ability of a powder to charge electrostatically during a flow in contact with a selected material. Both electrostatic and flow measurements have been performed in different hygrometric conditions. The correlation between the powder electrostatic properties, the hygrometry and the flowing behavior are analyzed.

Competition Between Resonant Plasmonic Coupling and Electrostatic Interaction in Reduced Graphene Oxide Quantum Dots.

The light emission from reduced graphene oxide quantum dots (rGO-QDs) exhibit a significant enhancement in photoluminescence (PL) due to localized surface plasmon (LSP) interactions. Silver and gold nanoparticles (NPs) coupled to rGO nanoparticles exhibit the effect of resonant LSP coupling on the emission processes. Enhancement of the radiative recombination rate in the presence of Ag-NPs induced LSP tuned to the emission energy results in a four-fold increase in PL intensity. The localized field due to the resonantly coupled LSP modes induces n-π* transitions that are not observed in the absence of the resonant interaction of the plasmons with the excitons. An increase in the density of the Ag-NPs result in a detuning of the LSP energy from the emission energy of the nanoparticles. The detuning is due to the cumulative effect of the red-shift in the LSP energy and the electrostatic field induced blue shift in the PL energy of the rGO-QDs. The detuning quenches the PL emission from rGO-QDs at higher concentration of Ag NPs due to non-dissipative effects unlike plasmon induced Joule heating that occurs under resonance conditions. An increase in Au nanoparticles concentration results in an enhancement of PL emission due to electrostatic image charge effect.

Electrostatic-Charge- and Electric-Field-Induced Smart Gating for Water Transportation.

Regulating and controlling the transport of water across nanochannels is of great importance in both fundamental research and practical applications because it is difficult to externally control water flow through nanochannels as in biological channels. To date, only a few hydrophobic nanochannels controlling the transport of water have been reported, all of which use exotic hydrophobic molecules. However, the effect of electrostatic charges, which plays an indispensable role in membrane proteins and dominates the energetics of water permeation across aquaporins, has not gained enough attention to control water transport through a solid-state nanochannel/nanopore. Here, we report electrostatic-charge-induced water gating of a single ion track-etched sub-10 nm channel. This system can directly realize the gating transition between an open, conductive state and a closed, nonconductive state by regulating the surface charge density through a process that involves alternating capillary evaporation and capillary condensation. Compared to the introduction of exotic hydrophobic molecules, water gating controlled by electrostatic charges is simple, convenient, and effective. Such a system anticipates potential applications including desalination, controllable valves, and drug delivery systems.