Ion Nonthermality Induced Nonlinear Dust Acoustic Wave Propagation in a Complex Plasma in Presence of Weak Secondary Electron Emission from Dust Grains

In this paper we have investigated the effect of ion nonthermality on nonlinear dust acoustic wave propagation in a complex plasma in presence of weak secondary electron emission from dust grains. Equilibrium dust charge in this case is negative. Dusty plasma under our consideration consists of inertialess nonthermal ions, Boltzman distributed primary and secondary electrons and negatively charged inertial dust grains. Both adiabatic and nonadiabatic dust charge variations have been taken into account. Our analysis shows that in case of adiabatic dust charge variation, at a fixed non-zero ion nonthermality increasing secondary electron emission decreases amplitude and increases width of the rarefied dust acoustic soliton whereas for a fixed secondary electron yield increasing ion nonthermality increases amplitude and decreases width of such rarefied dust acoustic soliton. Thus shape of the soliton may be retained if strength of both the secondary electron yield and the ion nonthermality are increased. Nonadiabatic dust charge variation shows that, at fixed non-zero ion nonthermality, increasing secondary electron emission suppresses oscillation of oscillatory dust acoustic shock at weak nonadiabaticity and pronounces monotonicity of monotonic dust acoustic shock at strong nonadiabaticity. On the other hand at a fixed value of the secondary electron yield, increasing ion nonthermality enhances oscillation of oscillatory dust acoustic shock at weak nonadiabaticity and reduces monotonicity of monotonic dust acoustic shock at strong nonadiabaticity. Thus nature of dust acoustic shock may also remain unchanged if both secondary electron yield and ion nonthermality are increased.

Effect of Electron and/or Ion Nonthermality on Dust Acoustic Wave Propagation in a Complex Plasma in Presence of Positively Charged Dust Grains Generated by Secondary Electron Emission Process

In this paper we have developed a model to study the role of both electron and ion nonthermalities on dust acoustic wave propagation in a complex plasma in presence of positively charged dust grains. Secondary electron emission from dust grains has been considered as the source of positive dust charging. As secondary emission current depends on the flux of primary electrons, nonthermality of primary electrons changes the expression of secondary emission current from that of earlier work where primary electrons were thermal. Expression of nonthermal electron current flowing to the positively charged dust grains and consequently the expression of secondary electron current flowing out of the dust grains have been first time calculated in this paper, whereas the expression for nonthermal ion current flowing to the positively charged dust grains is present in existing literature. Dispersion relation of dust acoustic wave has been derived. From this dispersion relation real frequency and growth rate of the wave have been calculated. Results have been plotted for different strength of nonthermalities of electrons and ions.

On the Thermal Distribution in Oncological Hyperthermia Treatments

The temperature is one of the principal controlling parameters of oncological hyperthermia. However, local heating forms a complicated thermal distribution in space and has developed over time, too. The decisional factors are the heterogeneity of the targeted volume, the electrolyte perfusions controlled by thermal homeostasis, and the spreading of the heat energy with time. A further complication is that the energy absorption sharply changes by depth, so the spatiotemporal development of the temperature distribution requires specialized methods to control. Most of the temperature imaging facilities (thermography, radiometry, electric impedance tomography, etc.) are less precise than the medical practice needs. In contrast, precise point sensing (like thermocouples, thermistors, and fluoroptical methods) is invasive and measures only a discrete point in the robustly changing thermal map. The two most precise thermal imaging methods, computer tomography, and magnetic resonance are expensive and have numerous technical complications. Our objective is to show the complexity of the temperature distribution inside the human body, and offer a relatively simple and cheap method to visualize its spatiotemporal development. A novel emerging technology, the application of ultrasound microbubble contrast agents is a promising method for solving complicated tasks of thermal distribution deep inside the living body. Noteworthy, the temperature distribution does not determine the full hyperthermia process, nonthermal effects make considerable impact, too. Additionally to the difficulties to measure the thermal heterogeneity during hyperthermia in oncology, numerous nonthermal processes, molecular and structural changes are triggered by the incoming electromagnetic energy, which presently has no spatiotemporal visualization technique. Microbubble imaging has a suitable spatiotemporal thermal resolution, and also it is sensitive to nonthermal effects. Its application for characterization of the modulated electrohyperthermia (mEHT) may open a new theranostic facility, using the synergy of the thermal and nonthermal effects of the radiofrequency delivered energy. This complex approach gives facility to follow the mEHT processes, and the proposed microbubble ultrasound imaging has a particularly promising advantage sensing and acting also nonthermally, having potential to characterize the thermally conditioned nonthermal electromagnetic effects in oncologic hyperthermia. The mEHT combined with microbubble ultrasound images could be a robust theranostic method against cancer.

Effect of ultrasound and microwave pretreatment on sprouting,GABA,bioactive compounds,and other physicochemical properties of sorghum

Aim of this study is to see how ultrasound(US)and microwave(MW)pretreatments affectγ-aminobutyric acid(GABA)and physicochemical parameters of sorghum sprouts.Before sprouting,the sorghum was treated with the US at different time intervals(10,15,20 min)and MW at various power levels(10%,30%,50%).Sample treated by the US for 15 min showed the highest sprouting percentage of 97.33%.Both treatments induced stress in grain resulting in GABA accumulation substantially from the control where US for 15 min and MW at 10%power level had the highest of 87.14 and 66.97μg/g,respectively.US treatment for 20 min showed the highest total phenolic content(TPC)of 21.26 mg GAE/100 g,while on 10 min of treatment,it showed the highest antioxidant activity of 84.53%DPPH inhibition.The water absorption capacity and oil absorption capacity were the highest of 0.86 g/g and 0.98 g/g in the MW-treated sample at 10%output power respectively.In conclusion,the ultrasound treatment successfully accelerated the sprouting rate and GABA content while retaining total phenolic content,making it beneficial for developing functional foods.

The Immunogenic Connection of Thermal and Nonthermal Molecular Effects in Modulated Electro-Hyperthermia

Hyperthermia in oncology is an emerging complementary therapy. The clinical results depend on multiple conditional factors, like the type of cancer, the stage, the applied treatment device, and the complementary conventional therapy. The molecular effect could also be different depending on the temperature, heating dose, kind of energy transfer, and timing sequences compared to the concomitant treatment. This article examines the molecular impacts of a specific technique used in oncological hyperthermia called modulated electro-hyperthermia (mEHT). What sets mEHT apart is its emphasis on harnessing the combined effects of thermal and nonthermal factors. Nonthermal energy absorption occurs through the excitation of molecules, while the thermal component ensures the ideal conditions for this process. The applied radiofrequency current selects the malignant cells, and the modulation drives the nonthermal effects to immunogenic cell death, helping to develop tumor-specific antitumoral immune reactions. The synergy of the thermal and nonthermal components excites the lipid-assembled clusters of transmembrane proteins (membrane rafts) as the channels of transient receptor potentials (TRPs), the heat-shock proteins (HSPs), the voltage-gated channels, and the voltage-sensitive phosphatases (VSPs). All these transmembrane compartments channeling various ionic species (like calcium and proton) interact with the cytoskeleton and are involved in the apoptotic signal pathways.

Study of Humidity Effect on Benzene Decomposition by the Dielectric Barrier Discharge Nonthermal Plasma Reactor

The humidity effects on the benzene decomposition process were investigated by the dielectric barrier discharge（DBD） plasma reactor.The results showed that the water vapor played an important role in the benzene oxidation process.It was found that there was an optimum humidity value for the benzene removal efficiency,and at around 60% relative humidity（RH）,the optimum benzene removal efficiency was achieved.At a SIE of 378 J/L,the removal efficiency was 66% at 0% RH,while the removal efficiency reached 75.3% at 60% RH and dropped to 69% at 80% RH.Furthermore,the addition of water inhibited the formation of ozone and NO2 remarkably.Both of the concentrations of ozone and NO2 decreased with increasing of the RH at the same specific input energy.At a SIE of 256 J/L,the concentrations of ozone and NO2 were 5.4 mg/L and 1791 ppm under dry conditions,whereas they were only 3.4 mg/L and 1119 ppm at 63.5%RH,respectively.Finally,the outlet gas after benzene degradation was qualitatively analyzed by FT-IR and GC-MS to determine possible intermediate byproducts.The results suggested that the byproducts in decomposition of benzene primarily consisted of phenol and substitutions of phenol.Based on these byproducts a benzene degradation mechanism was proposed.

NOx Reduction and Desorption Studies Under Electric Discharge Plasma Using a Simulated Gas Mixture:A Case Study on the Effect of Corona Electrodes

In this study, reduction and desorption of oxides of nitrogen （NOx） were conducted using an electrical discharge plasma technique. The study was carried out using a simulated gas mixture to explore the possibility of re-generation of used adsorbents by a nonthermal plasma desorption technique. Three different types of corona electrodes, namely, pipe, helical wire, and straight wire, were used for analyzing their effectiveness in NOx reduction/desorption. The pipe- type corona electrode exhibited a nitric oxide （NO） conversion of 50%, which is 1.5 times that of the straight-wire-type electrode at an energy density of 175 J/L. The helical-wire-type corona electrode exhibited a NOx desorption efficiency almost 4 times that of the pipe-type electrode, indicating the possibility that corona-generated species play a crucial role in desorption.

Detection of hydroxyl radical in plasma reaction on toluene removal

A new method was introduced to detect the concentration of OH radical in dielectric barrier discharge(DBD)reaction.A film, which was impregnated with salicylic acid,was used to detect OH radical in plasma reaction at room temperature and atmospheric pressure.Salicylic acid reacts with OH radical and produces 2,5-dihydroxybenzoic acid(2,5-DHBA).Then,a high performance liquid chromatography(HPLC)was carried out to detect the concentration of 2,5-DHBA.Therefore,OH radical in nonthermal plasma reaction could be...

催化等离子体反应器中低浓度硝基苯的消除(英文)

Oxidative decomposition of dilute nitrobenzene in air was carried out in a catalytic plasma reactor with an inner electrode made of sintered metal fibres(SMF)that also acted as catalyst.The parameters of the concentration,specific input energy,and gas residence time were optimized.The modification of the SMF inner electrode with transition metal oxides like MnOx and CoOx oxides promoted complete oxidation,especially at low input energy.CoOx/SMF showed higher activity than MnOx/SMF and SMF,and could oxidise completely 100 ppm of nitrobenzene at 300 J/L.

Short-living Supermassive Magnetar Model for the Early X-ray Flares Following Short GRBs

We suggest a short-lived supermassive magnetar model to account for the X-ray flares following short γ-ray bursts. In this model the central engine of the short γ-ray bursts is a supermassive millisecond magnetar, formed in coalescence of double neutron stars. The X-ray flares are powered by the dipole radiation of the magnetar. When the magnetar has lost a significant part of its angular momentum, it collapses to a black hole and the X-ray flares cease abruptly.

In vitro study of nonthermal atmospheric pressure plasma in improving the durability of the dentin–adhesive interface with an etch-and-rinse system

In this study, we employed a nonthermal atmospheric pressure plasma(NTAPP) jet to evaluate the effect of plasma treatment on the durability of resin–dentin bonding under a thermocycling challenge. Furthermore, we assessed the degradation resistance of plasma-treated collagen under a sodium hypochlorite(NaClO) challenge. We assessed the beneficial effect of NTAPP treatment on the acid-etched dentin–bonding interface by testing the micro-tensile bond strength and examining the morphology. We found that the immediate bonding strength of the dentin significantly increased after NTAPP treatment. Compared with the control group, NTAPP resulted in a more prominent effect on the bonding durability of the dentin–adhesive interface after treatment for 5 or 10 s. Simultaneously, the mechanical strength of dentin collagen under the NaClO challenge was improved. Our results indicate that, in optimal conditions, NTAPP could be a promising method to protect dentin collagen and to improve the bonding durability between dentin and etch-and-rinse adhesives.

Experimental study on the parameter optimization and application of a packed-bed dielectric barrier discharge reactor in diesel particulate filter regeneration

To compensate for the shortcomings of the thermal and catalytic regeneration of the diesel particulate filter(DPF),a self-designed packed-bed dielectric barrier discharge(DBD)reactor for DPF regeneration was developed.The DBD reactor with the main active substance of nonthermal plasma(NTP)as the target parameter was optimized by adjusting the feed gas,packing particles(material or size),and cooling water temperature.Moreover,a set of optimal working parameters(gas source,O_2;packing particles,1.2–1.4 mm ZrO_(2);and cooling water temperature,20℃)was selected to evaluate the effect of different O_(3) concentrations on DPF regeneration.The research results showed that selecting packing particles with high dielectric constant and large particles,as well as reducing the cooling water temperature,with oxygen as the feed gas,contributed to an increase in O_(3) concentration.During DPF regeneration,the following changes were observed:the power of the NTP reactor decreased to lower than 100 W,the O_(3) concentration increased from 15 g m^(-3) to 45 g m^(-3),the CO and CO_2 volume fractions of the particulate matter decomposition products increased,and the peak regeneration temperature increased to 173.4℃.The peak temperature arrival time was 60 min earlier,indicating that the regeneration rate of DPF increased with the increase in O_(3) concentration.However,the O_(3) utilization rate(the amount of carbon deposit removed per unit volume O_(3))initially increased and then decreased;when the O_(3) concentration was set to 25 g m^(-3),the highest O_(3) utilization rate was reached.The packed-bed DBD technology contributed to the increase in the concentration of NTP active substances and the regeneration efficiency of DPF.It provides a theoretical and experimental basis for high-efficiency regeneration of DPF at low temperatures(<200℃).

Plasma skincare device based on floating electrode dielectric barrier discharge

A portable skincare plasma-device with a rechargeable battery is presented here. The device comprises two pads made of thin polyimide film as the dielectric layer, namely, the dielectric barrier discharge pad(DBD-pad) for skin-touch and a capacitive ground-pad(G-pad) for hand holding. High AC voltage of approximately 1 kV with frequency of 40 kHz is induced in the DBD-pad that contacts the skin, which serves as the floating electrode, while low voltage is induced on the G-pad. Considering the requirement for impedance matching between the DBDpad capacitance and the inverter along with the need for low skin current less than approximately 5 mA for electrical safety, the electrode area of the DBD-pad is minimized to be smaller than that of the G-pad.

Hawking effect and quantum nonthermal radiation of an arbitrarily accelerating charged black hole using a new tortoise coordinate transformation

Using a new tortoise coordinate transformation, this paper investigates the Hawking effect from an arbitrarily accelerating charged black hole by the improved Damour-Ruffini method. After the tortoise coordinate transformation, the Klein-Gordon equation can be written as the standard form at the event horizon. Then extending the outgoing wave from outside to inside of the horizon analytically, the surface gravity and Hawking temperature can be obtained automatically. It is found that the Hawking temperatures of different points on the surface are different. The quantum nonthermal radiation characteristics of a black hole near the event horizon is also discussed by studying the Hamilton-Jacobi equation in curved spacetime and the maximum overlap of the positive and negative energy levels near the event horizon is given. There is a dimensional problem in the standard tortoise coordinate and the present results may be more reasonable.

High-efficiency removal of NO_x using dielectric barrier discharge nonthermal plasma with water as an outer electrode

With the rapid increase in the number of cars and the development of industry, nitrogen oxide （NOx） emissions have become a serious and pressing problem. This work reports on the development of a water-cooled dielectric barrier discharge reactor for gaseous NOx removal at low temperature. The characteristics of the reactor are evaluated with and without packing of the reaction tube with 2 mm diameter dielectric beads composed of glass, ZnO, MnO2, ZrO2, or Fe203. It is found that the use of a water-cooled tube reduces the temperature, which stabilizes the reaction, and provides a much greater NO conversion efficiency （28.8%） than that obtained using quartz tube （14.1%） at a frequency of 8 kHz with an input voltage of 6.8 kV. Furthermore, under equivalent conditions, packing the reactor tube with glass beads greatly increases the NO conversion efficiency to 95.85%. This is because the dielectric beads alter the distribution of the electric field due to the influence of polarization at the glass bead surfaces, which ultimately enhances the plasma discharge intensity. The presence of the dielectric beads increases the gas residence time within the reactor. Experimental verification and a theoretical basis are provided for the industrial application of the proposed plasma NO removal process employing dielectric bead packing.

Resonant cyclotron scattering in pulsar magnetospheres and its application to isolated neutron stars

Resonant cyclotron scattering （RCS） in pulsar magnetospheres is considered. The photon diffusion equation （Kompaneets equation） for RCS is derived. The photon system is modeled three dimensionally. Numerical calculations show that there exist not only up scattering but also down scattering of RCS, depending on the parameter space. RCS＇s possible applications to spectral energy distributions of magnetar candidates and radio quiet isolated neutron stars （INSs） are pointed out. The optical/UV excess of INSs may be caused by the down scattering of RCS. The calculations for RX J1856.5-3754 and RX J0720.4-3125 are presented and compared with their observational data. In our model, the INSs are proposed to be normal neutron stars, although the quark star hypothesis is still possible. The low pulsation amplitude of INSs is a natural consequence in the RCS model.

The Doppler Effect and Spectral Energy Distribution of Blazars

The relativistic beaming model is adopted to discuss quantitatively the observational differences between radio-selected BL Lac objects (RBLs) and X-ray- selected BL Lac objects (XBLs), and between BL Lac objects and flat spectrum radio quasars (FSRQs). The main results are the following: (1) In the Doppler corrected color-color ( ) diagram, XBLs and FSRQs occupy separated regions, while RBLs bridge the gap between them. These properties suggest that similar intrinsic physical processes operate in all the objects under a range of intrinsic physical conditions. (2) Our results are consistent with the results of Sambruna, Maraschi and Urry (1996) from other methods. We show the ■xox introduced by Sambruna to be a good index for describing the energy distribution because it represents the intrinsic energy distribution and includes the Doppler correction. (3) The Doppler effect of relativistic beaming is the main mechanism, and the physical differences (such as magnetic fields, electron energies) are also important complementary factors for understanding the relation between XBLs and RBLs;

Simple reactor for the synthesis of silver nanoparticles with the assistance of ethanol by gas-liquid discharge plasma

Atmospheric pressure plasma technology is gaining increasing importance because it is a simple and tunable synthesis process for the production of metallic nanoparticles.In addition to the development of the power supply,improving the reactor is also one of the main strategies to enhanee the utility.In this study,a simple reactor for the gas-liquid discharge plasma induced by argon gas was applied to synthesize silver nanopailicles from silver nitrate(AgNO3)in solution.An AC power supply with a peak voltage of 3.5 kV was used.The frequency and on-time were set to 50 kHz and 2.5“s,respectively.The oscilloscope showed that the rising time was approximately 2“s.The ethanol was used as the source for the reactive reducing agent.No more additional comp on ents existed in the solution during the discharge and neither of the electrodes was in contact with the treated solution.The temperature in creased by 10°C within 1 min without a cooling system.Carbon was the main impurity and was expected to be produced from the decomposition of the organics under the plasma.The elevated temperature decreased the organic by-products by evaporation and could also decrease the production of carbon.Transmission electron microscopy showed that the spherical silver nanoparticles with a size of approximately 10 nm were synthesized with a crystal structure and that a low concentration of ethanol prefers the production of the mono-dispersed colloid.

Silicone-coated polyimide films deposited by surface dielectric barrier discharges

Hybrid dielectric barrier discharges are investigated for plasma generated on the surface of a dielectric layer, where two conducting electrodes of high voltage and ground are formulated on the upper and bottom surfaces. Using a flexible thin polyimide-film of a thickness ranging from 25 to 125 μm, a plasma is generated with a voltage of about 1 kV and a frequency of 40 kHz.However, the surface of the dielectric layer was etched through a chemical reaction involving plasma oxygen radical species, and thus the polyimide films failed readily, resulting in dielectric breakdown within short operating time ranging from a few minutes to several tens of minutes,based on the film thicknesses of 25 μm and 125 μm, respectively. These plasma erosions were prevented by coating the polyimide surface with a 25 μm thick silicone paste. The siliconecoated film surface was then reinforced remarkably against plasma erosion as the organic polymer was vulnerable to chemical reaction of the plasma species, while the inorganic silicone exhibited a high chemical resistance against plasma erosion.

Behaviour of Trichloroethylene Decomposition in a Plasma-Catalytic Combined Process

A nonthermal plasma processing combined with Cr2O3/TiO2 catalyst was applied to the decomposition of trichloroethylene （TCE）. A dielectric barrier discharge reactor was used as the nonthermal plasma reactor. The effects of the reaction temperature and input power on the decomposition of TCE and the formation of byproducts including HCl, Cl2, CO, NO, NO2 and O3 were examined. With an identical input power, the increase in the reactor temperature lowered the decomposition of TCE. The presence of the catalyst downstream the plasma reactor not only enhanced the decomposition of TCE but also affected the distribution of byproducts significantly. However any synergetic effect as a result of the combination of the nonthermal plasma with the catalyst was not observed, i.e., the TCE decomposition ei^ciency in the plasma- catalyst combined system was almost similar to the sum of those obtained with each process. To improve the decomposition of TCE argon as a plasma-assisting gas was added to the feeding gas and a large enhancement in the TCE decomposition was achieved.