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This paper summarizes the objectives and experimental activity of the H2020 research project CAPTure, which officially lasted from May 2015 to July 2020. The main objective of the CAPTure project was the development and testing of several key components that allow the implementation of a solar powered combined cycle plant (topping Brayton cycle and bottoming Rankine steam cycle). The main innovation was related to the coupling of the open volumetric air receiver (OVAR) with the pressurized air stream of the Brayton cycle, i.e. the external heating of the Brayton cycle with hot air at atmospheric pressure. One key component was therefore a gas-gas heat exchanger, which was implemented as regenerator (atmospheric heating – pressurized cooling). A 300 kWth prototype, consisting of the solar receiver, the regenerative system and a small-scale Brayton cycle, was designed and implemented at CIEMAT-PSA. The paper describes the CAPTure prototype and the experimental activity performed until September 2021. [ABSTRACT FROM AUTHOR]

Air pollution by particulate matter with a particle diameter between 2.5 and 10 μm (PM10) is going up recently in the entire Danube region, Bulgaria [1, 2, 5, 6]. The sources of dust on the territory of Bulgaria are industry, transport and domestic heating by solid fuel [12]. PM10 levels for the Danube region in Bulgaria mark a significant increase during the autumn-winter period compared to the levels during the spring-summer period. For example in Ruse – a city belonging to this region the levels of PM10 are going up recently [5]. The biggest peak of PM10 levels for the autumn-winter period is usually observed in January months. It is in January that the number of days in which there is exceedance of the limit values of the PM10 levels is maximum observed. This paper is one continuation of our investigations of PM10 pollution for Danube region, Bulgaria especially for another city of the region - Silistra. It is devoted to examine the PM10 pollution during winter and its relationship with atmospheric characteristics (temperature, atmospheric pressure and humidity). It presents a statistical analysis of the level of PM10 air pollution in Silistra using data from the official monitoring stations in the city. The measurements cover the period since 2011 till 2017. Descriptive statistics of PM10 and atmospheric characteristics – temperature, atmospheric pressure and relative humidity as well as linear regression modeling are presented and commented in the paper. [ABSTRACT FROM AUTHOR]

Air pollution by particle matter (PM10 - particulate matter with a diameter between 2.5 and 10􀈝m) is going up recently in Ruse region, Bulgaria [1,2]. It becomes clear also recently that the mean values of the temperature in Ruse region are slightly goes up for the last 40 years and they are bigger than the mean temperature for Bulgaria. This could be a proof for climate change and warming in Ruse region. The presence of PM10 maybe affects the main atmospheric characteristics - temperature, atmospheric pressure and humidity. In our work [3] we examined in more details the influence of the temperature on the PM10 contamination during January months. This paper is one continuation of [3] and is devoted to examine the PM10 pollution in Ruse region during winter and its relationship with some other atmospheric characteristics (atmospheric pressure and humidity). It presents a statistical analysis of the level of PM10 air pollution in Ruse using data from the monitoring stations in the city [4]. The measurements cover the period since 2011 up to now. Descriptive statistics of PM10 as well as linear regression modeling are also presented and commented in the paper. [ABSTRACT FROM AUTHOR]

Theoretical researches of operating processes of slow-speed reciprocating compressor stages with linear drive, conducted by the authors of this paper, have determined the experimental confirmation necessity for gas compression possibility in one stage up to pressure 10.0 MPa and above at atmospheric suction pressure. The testing results of the newly developed experimental slow-speed piston compressor stage with linear hydraulic drive are presented in the paper at the ratio of the discharge to suction pressure values from 50 to 100. [ABSTRACT FROM AUTHOR]

Plasma technology based on diffuse coplanar surface barrier discharge DCSBD represents novel method of economic, efficient and versatile way of materials treatment. As the example of atmospheric pressure plasma source finds an application in modification of wide surface areas within high speed and enables homogenous in-line plasma treatment. Also, the technique of DCSBD plasma is known for its usage and testing in environmental, bio-medical and industrial areas. Also, it is capable of producing various types of active particles e. g. electrons, atoms, ions, radicals, photons, etc. in different processing gases. The focus of this paper was aimed at the modification of unvulcanized rubber blend by diffuse coplanar surface barrier discharge in order to improve the rheology and physical mechanical properties. Also, the impact of plasma on structural properties of raw rubber blend was studied and the effect of the possible surface crosslinking. [ABSTRACT FROM AUTHOR]

The atmospheric pressure plasma jet with low frequency and argon as working gas is presented in this paper to demonstrate its application for glass substrate clean and modification. The glass substrate clean by atmospheric pressure plasma jet is an efficient method to replace other substrate clean method. A comparative analysis is done in this paper between substrate cleaned by chemical and plasma treatment methods. Water contact angle reading is taken for a different method of substrate clean and period of treatment. Under the plasma treatment, the sample shows low surface adhesion due to having the surface property of super hydrophilic surface 7.26°. This comparative analysis is necessary in the industrial application for cost production due to sufficient time and method of substrate clean. [ABSTRACT FROM AUTHOR]

The atmospheric pressure plasma jet with low frequency and argon as working gas is presented in this paper to demonstrate its application for glass substrate clean and modification. The glass substrate clean by atmospheric pressure plasma jet is an efficient method to replace other substrate clean method. A comparative analysis is done in this paper between substrate cleaned by chemical and plasma treatment methods. Water contact angle reading is taken for a different method of substrate clean and period of treatment. Under the plasma treatment, the sample shows low surface adhesion due to having the surface property of super hydrophilic surface 7.26°. This comparative analysis is necessary in the industrial application for cost production due to sufficient time and method of substrate clean. [ABSTRACT FROM AUTHOR]

In this paper, we report significant progress in development and integration of a plasma-less atmospheric pressure dry texturing (ADE) process, performed on multicrystalline silicon (mc-Si) wafers, into high efficiency PERC solar cell architectures using industrially applied process steps. The mechanism of forming sub-micron features on monocrystalline and multicrystalline silicon wafers with commercial grade fluorine gas (F2) is briefly presented. Low weighted surface reflection (Rw,min < 10%) is achieved for mc-Si substrates regardless of the wafer sawing method. Mc-Si PERC solar cells with average conversion efficiencies of 20% are fabricated in the industrial pilot line of Hanwha Q-Cells in Thalheim. A detailed characterization of ADE-textured solar cells suggest that an enhancement in conversion efficiency of up to +0.8% absolute is possible in comparison to the reference-textured solar cells by narrowing the distribution of reflectivity in the textured wafer surface. [ABSTRACT FROM AUTHOR]

Atmospheric pressure plasma driven by Neon transformer power supply argon is presented in this paper. Atmospheric pressure plasma system has attracted researcher interest over low pressure plasma as it provides a flexibility process, cost-efficient, portable device and vacuum-free device. Besides, another golden key of this system is the wide promising application in the field of work cover from industrial and engineering to medical. However, there are still numbers of fundamental investigation that are necessary such as device configuration, gas configuration and its effect. Dielectric barrier discharge which is also known as atmospheric pressure plasma discharge is created when there is gas ionization process occur which enhance the movement of atom and electron and provide energetic particles. These energetic particles can provide modification and cleaning property to the sample surface due to the bombardment of the high reactive ion and radicals to the sample surface. In order to develop atmospheric pressure plasma discharge, a high voltage and high frequency power supply is needed. In this work, we used a neon transformer power supply as the power supply. The flow of the Ar is feed into 10 mm cylinder quartz tube with different treatment time in order to investigate the effect of the plasma discharge. The analysis of each treatment time is presented by optical emission spectroscopy (OES) and water contact angle (WCA) measurement. The increase of gas treatment time shows increases intensity of reactive Ar and reduces the angle of water droplets in water contact angle. Treatment time of 20 s microslide glass surface shows that the plasma needle discharges have modified the sample surface from hydrophilic surface to superhydrophilic surface. Thus, this leads to another interesting application in reducing sample surface adhesion to optimize productivity in the industry of paintings, semiconductor and more. [ABSTRACT FROM AUTHOR]

Temperature, air humidity and atmospheric pressure measurements in Ruse region for 40 years period are statistically studied in this paper. Descriptive statistics, Pearson correlation coefficients and linear regression models for these characteristics are presented and commented. The most variable atmospheric parameter is air humidity during the spring seasons. The hardest change of temperature and atmospheric pressure is during January. Temperature has biggest change in January and smallest - in July. Humidity has biggest change in April and smallest - in October. Atmospheric pressure has biggest change in January and smallest - in July. Characteristics temperature and atmospheric pressure of spring (April) and autumn (October) are very similar. Summer temperatures and atmospheric pressure (July) have smallest change. The atmospheric temperature data for Ruse region are also compared with the official basic data for Bulgaria. It is shown that mean values of the temperature in Ruse region are bigger than the mean temperature for Bulgaria. It is shown that the winter and spring temperatures for Ruse region are slightly going up lately which could be connected with the typical for Ruse region air pollution especially by particle matter. [ABSTRACT FROM AUTHOR]

It is shown in the paper that the reliability and efficiency of self-draining systems of the drainback syphon type depend on the atmospheric pressure and heating temperature of the heat carrier in the solar collectors, which affect the value of the allowable drop of the atmospheric pressure in the upper point of the system after it is filled with the heat carrier and achieves the specified heat operation mode. In such systems, the drop of the atmospheric pressure and growth of the heating temperature of the heat carrier lead to an increase in the power consumption for the heat carrier circulation owing to the interruption of the jet in the syphon because of the boiling of the heat carrier. An improved structure of the self-draining solar circuit with an active element in the form of a Venturi tube was developed in which there are no such drawbacks under atmospheric pressure. Compared to the common self-draining system of the drainback syphon type, the power consumption for the heat carrier circulation is reduced to 65-80%. The calculated dependencies are given to define the necessary degree of the flow contraction in the Venturi tube and its resistance coefficients. The article considers experimental studies of the hydrodynamic characteristics of the active section of the self-draining solar loop of a heating system. This element is designed as a flow constrictor referred to as a Venturi tube, with a high degree of flow constriction of 2–5 in.the region with strong viscous resistance. The experimental data are processed in a criteria form, the general type obtained by dimensional technique and compared with data from other authors. The obtained criteria dependencies can be used to calculate the hydrodynamic characteristics of the active section of the self-draining solar loop of a heating system. [ABSTRACT FROM AUTHOR]

The prediction of critical heat flux (CHF) phenomenon at atmospheric pressure was carried out using computational fluid dynamics (CFD) methods. Heat transfer experiments of flow boiling will be validated at the University of West Bohemia, where an experimental apparatus is built. The test section consists of one 3000 mm long resistance heated fuel rod imitator (HRI) with an outer diameter of 9.1 mm placed in an annular tube. Several spacer grids are used on the experimental device to hold the heated rod imitator in its position while improving the internal heat transfer. All simulations presented in this paper started with the same inlet conditions, while the heating input gradually increased until the two-phase flow reached a steady state. The successfully predicted CHF happened through a liquid sublayer dryout under very high vapor volume fractions (93+ %) which led to complete thermal isolation of the HRI. Thanks to the results of the CFD simulations, the temperature measuring system on the experimental loop could be optimized. [ABSTRACT FROM AUTHOR]

The electron accelerator ELV6 is used as a heat source for the synthesis of nanoscale powders. The system for releasing the beam into the atmosphere allows vaporizing substances at atmospheric pressure, which makes it possible not only to increase the performance of removing nanoparticles from the reactor, but also allows using the carrier gas as one of the reagents in the process of particle synthesis. This paper describes the reactions that occur with the vaporized substance under conditions of high temperatures, radiation and electric fields. [ABSTRACT FROM AUTHOR]

In this paper atmospheric pressure microwave discharge methods and devices used for producing the non-thermal plasmas for processing of gases are presented. The main part of the paper concerns the microwave plasma sources (MPSs) for environmental protection applications. A few types of the MPSs, i.e. waveguide-based surface wave sustained MPS, coaxial-line-based and waveguide-based nozzle-type MPSs, waveguide-based nozzleless cylinder-type MPS and MPS for microdischarges are presented. Also, results of the laboratory experiments on the plasma processing of several highly-concentrated (up to several tens percent) volatile organic compounds (VOCs), including Freon-type refrigerants, in the moderate (200–400 W) waveguide-based nozzle-type MPS (2.45 GHz) are presented. The results showed that the microwave discharge plasma fully decomposed the VOCs at relatively low energy cost. The energy efficiency of VOCs decomposition reached 1000 g/kWh. This suggests that the microwave discharge plasma can be a useful tool for environmental protection applications. In this paper also results of the use of the waveguide-based nozzleless cylinder-type MPS to methane reforming into hydrogen are presented. [ABSTRACT FROM AUTHOR]

In Vacuum Assisted Resin Transfer Molding (VARTM), fiber preform is placed on a rigid tool and sealed with a flexible plastic bag. Vacuum is drawn at the vent to compact the preform under atmospheric pressure with the injection line closed. When the injection line is opened the resin flows into the preform. The pressure of the incoming resin relieves some of the pressure being borne by the preform which increases the thickness of the preform during the infusion process. As the resin pressure varies from the injection location to the vent, the thickness of the part will not be uniform due to this resin pressure variation and its coupling with the compression characteristics of the preform. Compaction studies of the preform have identified elastic, plastic, and even viscoelastic behavior and a change in behavior as one goes from a dry preform to a wet preform (lubricated). This paper will describe results from a model that couples the fiber compaction behavior with the resin infusion process. Experiments will be conducted to measure the thickness of the preform during and after the infusion process is complete. The results will be compared with the model to identify the importance of the preform deformation in manufacturing of composites parts with the VARTM process. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The production of high-quality thermoplastic parts often requires an additional process step after the injection molding stage. This may be a coating, bonding process or a 2K-injection moulding process. A commonly used process to improve the bond strength is atmospheric pressure plasma treatment. A variety of applications are realized with the aid of CNC systems. Although they ensure excellent reproducibility, they make it difficult to implement inline applications. This paper therefore examines the possibility of surface treatment using a stationary plasma jet. However, before it is possible to integrate this technology into a production process, preliminary trials need to be carried out to establish which factors influence the process. Experimental tests were performed using a special test set-up, enabling geometric, plasma-specific parameters to be identified. These results can help with the practical integration of this technology into existing production processes. [ABSTRACT FROM AUTHOR]

Powder Metallurgy (PM) manufacturing process offers a more flexible and adaptable method for mass production of required components compared to traditional methods such as casting precision components. The combination of optimised manufacturing techniques and new material systems allows the production of this material. Powder metallurgy increases the utilisation efficiency of materials with high density and excellent mechanical properties, reduces the need for machining, reduces complex shapes, allows the configuration of various variables and with a wide range of property variations. Eliminates possible waste and guarantees a high production rate. In powder manufacturing, the three main methods are mechanical, chemical, and physical powder manufacturing methods. However, the powder metallurgy process comprises of four necessary steps: powder manufacturing, powder mixing, compression, and sintering. Compression is done at room temperature and the high-temperature sintering process at atmospheric pressure. In this paper, an overview of the powder metallurgy process, the processing steps required to obtain complex shapes, material properties, commonly used manufacturing approaches, and the advantages of using this method in many industries, also describes the manufacturing process. [ABSTRACT FROM AUTHOR]

The International Fire Code has classified Subatmospheric Gas Delivery Systems (SAGS) technologies into two main categories: SAGS Type I and SAGS Type II systems. SAGS Type I delivery systems both store and deliver gases at subatmospheric pressures. An example of this technology is ATMI's Safe Delivery Source (SDS®) adsorbent based cylinder. SAGS Type II delivery systems store fluids at high pressure and utilize mechanical devices internal to the cylinder to deliver the gas at subatmospheric pressures. Typical mechanical devices used to enable subatmospheric delivery are either set point regulators or mechanical capillary based systems. This paper focuses on how these delivery systems perform against the unique requirements of traditional beam line ion implantation as well as solar and flat panel applications. Specifically, data are provided showing the capability of these systems with respect to flow rate, residual gas left within the cylinder, and cylinder end-point flow and delivery pressure dynamics. [ABSTRACT FROM AUTHOR]

This paper presents a time domain formulation of nonlinear lossy propagation in onedimension that also includes the effects of non-collinear mean flow in the acoustic medium. The model equation utilized is an augmented Burgers equation that includes the effects of nonlinearity, geometric spreading, atmospheric stratification, and also absorption and dispersion due to thermoviscous and molecular relaxation effects. All elements of the propagation are implemented in the time domain and the effects of non-collinear mean flow are accounted for in each term of the model equation. Previous authors have presented methods limited to showing the effects of wind on ray tracing and/or using an effective speed of sound in their model equation. The present work includes the effects of mean flow for all terms included in the augmented Burgers equation with all of the calculations performed in the time-domain. The capability to include the effects of mean flow in the acoustic medium allows one to make predictions more representative of real-world atmospheric conditions. Examples are presented for nonlinear propagation of N-waves and shaped sonic booms. [Work supported by Gulfstream Aerospace Corporation.] [ABSTRACT FROM AUTHOR]

Recent work has brought about a renewed interest in CO2 laser ablation studies of polyoxymethylene, due to its potential as a test target for enhancing modern understanding of the laser ablation process. In this paper, new results taken in air at atmosphere pressure are reported, including data measured at institutions in Germany and Japan, which increase the body of literature data on CO2 laser ablation of polyoxymethylene. The results are discussed in terms of aerospace parameters such as the momentum coupling coefficient and specific impulse, and are compared to a previous literature study. The threshold fluence is specified for ablation of polyoxymethylene by CO2 laser radiation. Fluences higher (and lower) than previously tested for CO2 laser ablation were studied herein, and record specific impulse values for CO2 laser ablation of flat polyoxymethylene are also reported here. [ABSTRACT FROM AUTHOR]

Radio-frequency (RF), atmospheric-pressure glow discharge (APGD) plasmas with bare metallic electrodes have shown their promising prospects in different fields. In this paper, based on the induced gas discharge approach, the discharge characteristics of RF, APGD plasmas using helium/oxygen mixture as the plasma working-gas are presented. The bio-medical effects of the helium RF APGD plasma jet acting on the gfp DNA and E. coli are also reported. Studies concerning the lethal and sub-lethal effects of the RF APGDs on the molecular and cell levels, which are related with the characteristics of the plasmas and their operation conditions are necessary in the future work based on a closer cooperation between the researchers in the field of the plasma science & technology and of the bio-medical science. [ABSTRACT FROM AUTHOR]

In recent years germanium has been increasingly used in ion implant applications, for example for pre-amorphization and materials-properties modification. Almost without exception the pre-cursor feed material used is GeF4 gas, introduced into the ion source from pressurized or sub-atmospheric storage. However, a common limitation of this arrangement is significantly reduced ion-source life due to tungsten redeposition within the arc chamber. This paper reports the evaluation of an alternative feed-gas, specifically GeH4. Previously avoided in the implant community, at least in part because of undesirable physical and chemical properties, recent advances in sub-atmospheric delivery have prompted review of this material. The effect of this gas on source life is studied, as is the ionization fragmentation pattern as revealed by beam characterization and SIMS isotope profiling of implanted samples. Comparisons are drawn with GeF4 in highlighting future potential for this feed gas in ion implant applications. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

BNM-LNE had studied Pt/Pd thermocouple behavior with the aim of adopting this type of sensor as an approximation of the ITS-90 above 660 °C. In order to complete a set of fixed-point cells which are available for the calibration of Pt/Pd thermocouples and other Pt-based thermocouples, BNM-LNE has recently developed an open copper fixed-point cell. This cell was developed as a test cell in order to improve the realization method, to estimate uncertainty contributions and also to determine the freezing temperature traceable to ITS-90. The cell was checked using a copper fixed-point mini-cell. This paper describes all the steps of the construction needed for cell realization and its characterization. The choice to manufacture an open cell at this point is justified in the paper. Metal impurities, metal filling conditions in the cell and atmospheric pressure effects are studied. The freezing temperature of ITS-90 was preliminarily estimated by contact thermometry awaiting a comparison with a radiation thermometry realization. The consistency of this estimated uncertainty will be confirmed by a comparison with other NMI facilities organized in Europe (Euromet project 624). This comparison is under process. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

The atmospheric pressure plasma needle jet driven by double sinusoidal waveform of neon transformer is reported in this paper. The commercial neon transformer produces about 5 kV of peak sinusoidal voltages and 35 kHz of frequency. Argon gas has been used as discharge gas for this system since the discharge was easily developed rather than using helium gas. In addition, argon gas is three times cheaper than helium gas. The electrical property of the argon discharge has been analyzed in details by measuring its voltage, current and power during the discharge process. Interestingly, it has been found that the total power on the inner needle electrode was slightly lower than that of outer electrode. This may be due to the polarization charges that occurred at inner needle electrode. Then, further investigation to understand the discharge properties was carried out using optical emission spectroscopy (OES) analysis. During OES measurements, two positions of plasma discharge are measured by aligning the quartz optical lens and spectrometer fiber. The OH emission intensity was found higher than that of N2 at the plasma orifice. However, OH emission intensity was lower at 1.5 cm distance from orifice which may be due to penning ionization effect. These results and understanding are essential for surface modification and biomedical applications of atmospheric pressure plasma needle jet. [ABSTRACT FROM AUTHOR]

Systems of simultaneous or parallel chemical reactions of the type A → B → C → Other products are often treated as first order or pseudo-first order. For a system of simultaneous first and second order reactions -- dB/dt = &abA - kBcB² and dC/dt = kbcB² - kcC, where A, B, and C are concentrations, t is time, and the reaction rate parameters kAB and kc in yr-1 are lst-order and kBC in cm³ molecule-1 yr-1 is 2nd-order -- no explicit solution is available, as far as we are aware. This paper presents explicit and asymptotic solutions of simultaneous 1st- and 2nd order Riccati equations and applies them to a simplified sequence of gas reactions in the atmosphere of Titan, the largest satellite of Saturn: CH4 methane (1st order, k 12) → CH3 methyl (2nd order, k23) → C2H6 ethane (1st order, k3) → Other products. The Titan's atmosphere contains methane (CH4) at the present-day partial pressure of 0.1 bar, out of a total atmospheric pressure made up by nitrogen (N2) of 1.5 bar, comparable to Earth's. Methyl CH3 and ethane C2H6 are minor components. On Titan, methyl (CH3) is an intermediate product from methane to ethane, the latter raining out as liquid on Titan's surface. The main points of this paper are: (1) the asymptotic solutions that approximate near-steady state of Titan's atmosphere about 4.5 billion years after its accretion; (2) the computed present-day concentrations of the three gases in Titan's scale atmosphere (i.e., scale atmosphere is a model of an isothermal well mixed reservoir); and (3) the agreement between Titan's reported and computed atmospheric concentrations of CH4, CH3, and C2H6. The reaction rate parameters of the species are constants representative of their mean values during the satellite's cooling history. The present-day concentrations of methyl (CH3) and ethane (C2H6) are several orders of magnitude lower than the concentration of methane (CH4). Since Titan's accretion about 4.5 billion years B.P., steady-state concentrations of methane and ethane would have been attained in less than 500,000 years. This conclusion and the agreement of the model results with the reported concentrations underscores validity of the asymptotic solutions derived from the explicit solutions, and the long-term stability of the carbon cycle in Titan's atmosphere. [ABSTRACT FROM AUTHOR]

In this paper, the atmospheric pressure chemical vapor deposition (AP-CVD) is used to synthesize graphene on a copper substrate by utilizing methane as a precursor and N-doped graphene (NDG) in the presence of ammonia. The performance of pure titanium dioxide (TiO2), TiO2/graphene, and TiO2/NDG as photoanodes in dye-sensitized solar cell (DSSC) were compared. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) showed flakes of few layers with an interrupted layer in both graphene and NDG. DSSC consist of TiO2/NDG photoanode exhibits a better enhancement due to the high conductivity of donor N in graphene which enhances the electron transportation across nanoporous TiO2. [ABSTRACT FROM AUTHOR]

In this paper, we report the new production method amorphous carbon grown on sharpened tungsten electrode at atmospheric pressure by using high voltage pulsed methane discharge. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper describes the fundamental experimental data of the plasma surface modification of the polyimide using atmospheric pressure microwave plasma source. The experimental results were discussed from the point of view of the radical's behavior, which significantly affects the modification mechanism. The purpose of the study is to examine how the value of the oxygen atom density will affect the hydrophilic treatment in the upstream region of the plasma where gas temperature is very high. The surface modification experiments were performed by setting the polyimide film sample in the downstream region of the plasma. The degree of the modification was measured by a water contact angle measurement. The water contact angle decreased less than 30 degrees within 1 second treatment time in the upstream region. Very high speed modification was observed. The reason of this high speed modification seems that the high density radical which contributes the surface modification exist in the upstream region of the plasma. This tendency is supposed to the measured relatively high electron density (~1015cm-3) at the center of the plasma. We used the electric heating catalytic probe method for oxygen radical measurement. An absolute value of oxygen radical density was determined by catalytic probe measurement and the results show that ~1015cm-3 of the oxygen radical density in the upstream region and decreases toward downstream region. The experimental results of the relation of the oxygen radical density and hydrophilic modification of polyimide was discussed. [ABSTRACT FROM AUTHOR]

It is known that convection contributes to the natural mixing of melts due to the uneven distribution of their density. This mixing can be enhanced by various devices and by changing the conditions surrounding the flow region of the medium, e.g. by changing the pressure at the boundaries of the flow region of such fluid media. A pressure difference inside the region filled with a viscous fluid can induce its flow. A classic example of such a flow is the Poiseuille flow. Moreover, if the pressure distribution depends also on horizontal coordinates (i.e., there is a pressure difference not only in the vertical direction), then longitudinal pressure gradients also generate additional flows, which are superimposed on the classical flow. The paper studies the effect of pressure on the shear convective flow of a viscous incompressible binary fluid in a horizontal layer. To describe such flows, we use a system of equations of concentration convection, which includes the equation of motion of a viscous binary fluid, the equation of a concentration change, and the incompressibility equation. The solution of the system of constitutive equations is sought with the use of the class of generalized solutions, in which the velocities depend only on the vertical coordinate, the pressure and concentration being also linearly dependent on the longitudinal (horizontal) coordinates. As the boundary conditions, it is assumed that the no-slip condition is met at the lower impermeable boundary, that the upper boundary of the layer is motionless, and that the distribution of salinity and pressure is specified on it. The solution of the formulated boundary value problem is a set of polynomial functions. The highest-degree polynomial describes background pressure. The study of the properties of background pressure and the longitudinal pressure gradients is in the focus of attention. It is shown that background pressure decreases strictly monotonically with moving away from the lower boundary of the layer, regardless of the control parameters of the boundary value problem. In this case, the longitudinal pressure gradients are also described by strictly monotonic functions, but the nature of the monotonicity is determined by the values of the longitudinal concentration gradients specified at the upper boundary of the fluid layer. The relevant findings are illustrated. [ABSTRACT FROM AUTHOR]

Equation of state (EOS) for unreacted explosives, PETN has been formulated thermodynamically aiming at using with numerical code of shock to detonation transition processes. In this paper, a generalized procedure of providing pressure-volume-enthalpy EOS is proposed from the available static isothermal compression curve. The present formula can be used to describe the Rice-Walsh type EOS by using the specific heat at constant pressure as a function of entropy, Cp(S), and pressure-dependent Wu-Jing parameter with the material parameter β introduced by the author. Birch-Murnaghan functional form is adopted as an isothermal compression curve. Specific heat function was derived from the measured temperature dependence at atmospheric pressure. In order to estimate the parameter β in the Wu-Jing parameter, shock Hugoniot curve for PETN were calculated varying the value, β as a parameter. Value of β determined to reproduce the shock Hugoniot for both TMD and porous samples were found to be very similar and very small compared with those estimated for various metals. [ABSTRACT FROM AUTHOR]

This paper describes the design and operational test of the Power Control Unit (PCU) of the RX-320 Atmospheric Payload sounding rocket. RX-320 is a sounding rocket developed by the National Institute of Aeronautics and Space of the Republic of Indonesia (LAPAN), department of Rocket Technology Center. As a sounding rocket, the RX-320 Atmospheric Payload contains atmospheric meteorological sensors, and should measure the atmospheric parameters such as pressure, temperature and humidity, also the atmospheric gas parameters, such as carbon dioxide, ozone and nitrogen dioxide. The RX-320 Atmospheric Payload sounding rocket also have separation system to perform separation between rocket payload and rocket motor at the maximum altitude after lift off. The PCU should provide power for all of the electronic components so the RX-320 Atmospheric Payload can perform the mission. Power budget of the system has been iterated to provide the PCU criteria and design. Smart load balance has been designed for two-channel batteries to provide balanced load of each battery. The functional and load tests have been performed, that indicated the PCU is in the right way to support the RX-320 sounding rocket mission. [ABSTRACT FROM AUTHOR]

This paper reports on the investigation of flow structure and turbulent mixing in model Turbomeca swirl burner at atmospheric pressure with different Reynolds numbers by optical diagnostics (planar laser-induced fluorescence) and numerical simulation (large eddy simulation). The numerical simulation shows the good agreement with the experimental results. The operating modes of the combustion chamber presented in the work show unsatisfactory mixing of air with fuel in the initial region of the flow. In order to provide good mixing air and fuel at the atmospheric pressure in initial region of the flow after nozzle it is necessary supply fuel into the premixer through small channels. [ABSTRACT FROM AUTHOR]

In this paper, experimental results on atmospheric pressure argon dielectric barrier discharge (DBD) have been presented. The discharge was generated using a high voltage (0 to 20 kV) power supply operating at frequency of 10 to 30 kHz and was studied by means of electrical and optical measurements. A homogeneous and steady discharge was observed between the electrodes with gap spacing from 1 mm to 3 mm and with a dielectric barrier of thickness 1.5 mm while argon gas is fed at a controlled flow rate of 2liter per min. The electron temperature (Te) and electron density (ne) of the plasma have been determined by means of optical emission spectroscopy. Our results show that the electron density is of the order of 1016 cm-3 while the electron temperature is estimated to be ~ 1 eV. The homogeneity and non-thermal nature of the discharge were utilized in the investigation of the change in wettabilty of a polymer sample subjected to the treatment by the discharge. Contact angle analysis showed that the discharge was effective in improving the wettability of low density Polyethylene (LDPE) polymer sample after the treatment. [ABSTRACT FROM AUTHOR]

Many of the present day accelerators are based on superconducting radio frequency (SRF) cavities, packaged in cryo-modules (CM), which depend on helium refrigeration at sub-atmospheric pressures, nominally 2 K. These specialized helium refrigeration systems are quite cost intensive to produce and operate. Particularly as there is typically no work extraction below the 4.5-K supply, it is important that the exergy loss between this temperature level and the CM load temperature(s) be minimized by the process configuration choices. This paper will present, compare and discuss several possible helium distribution process arrangements to support the CM loads. [ABSTRACT FROM AUTHOR]

Bubble behavior under instable flow at atmospheric pressure were investigated in this paper. The visualization experiments were carried out on a vertical, narrow rectangular test section, with one side heating surface and upward flow. The section of the channel is 40×2mm. Mass flow ranged from 80 to 200kg/h, heat fluxes from 24 to 500kW/m2 and the subcooling from 5 to 35K. High-speed photography at rate of 5000 frames/s captured bubble behaviors. Bulk liquid velocities were found to fluctuat under instable flow, and backflow was observed. The bubbles were generated periodically. A few bubbles with smaller diameter and no sliding generated when the flow reversed. Many bubbles with larger diameter and long distance of sliding were generated as the flow velocity increased. [ABSTRACT FROM AUTHOR]

An Annular Solar Eclipse (ASE) occurred on 15 January 2010, which was observed in most parts of India. This paper reports the changes observed in solar irradiance and meteorological parameters (temp [T], relative humidity [RH] and dew point) associated with the ASE mainly at three locations (Greater Noida, Kanpur and Hyderabad) in India that are located far away from the eclipse path. A decrease in solar irradiance in the range of 25-59% (maximum in Hyderabad and minimum in Greater Noida) as well as a slight decrease in RH is observed during solar eclipse. The radiosonde and AIRS data show changes in the normal trend of meteorological conditions at different pressure levels indicating strong influence of solar eclipse. [ABSTRACT FROM AUTHOR]

Early investigations of the effects of treating materials with ionizing radiations began in 1894 with the irradiation of gases at atmospheric pressure using cathode rays from a Crookes gas-discharge tube, in 1895 with the discovery of X-rays emitted from a Crookes tube, and in 1896 with the discovery of radioactivity in uranium. In 1897, small electrically charged particles were detected and identified in the gas discharges inside Crookes tubes. These particles were then named electrons. During the next three decades, it was found that these novel forms of energy could produce ions to initiate chemical reactions in some gases and liquids. By 1921, it had also been shown that insects, parasites and bacteria could be killed by treatment with ionizing radiation. In 1925, a high-vacuum tube with a thermionic cathode and a thin metallic anode was developed to produce electron beams in air by using accelerating potentials up to 250 kilovolts. That unique apparatus was the precursor of the many types of electron accelerators that have been developed since then for a variety of industrial applications. In 1929, the vulcanization of natural rubber without using any chemical additives was achieved by irradiation with electrons from a 250 kilovolt accelerator. In 1939, several liquid monomers were polymerized by treatment with gamma rays from radioactive nuclides. These early results were not exploited before the end of World War II because intense sources of ionizing radiation were not available then. Shortly after that war, there was increased interest in developing the peaceful uses of atomic energy, which included the chemical and biological effects of radiation exposures. Many uses that have been developed since then are described briefly in this paper. These industrial applications are now producing billions of US dollars in revenue every year. [ABSTRACT FROM AUTHOR]

The force that acts on a thin vane immersed in rarefied gas when a temperature gradient is imposed along or across the vane has historically been known as the Radiometric force. First observed by Fresnel in 1825, the radiometric force has regained its former popularity in recent decades due to the advent of micro-machines, where a transitional flow regime can occur at atmospheric pressures. Whether used for its force potential or simply viewed as a nuisance, this force cannot be ignored in micro-devices where thermal gradients exist. Potential applications of radiometric force now span from atomic force microscopy to astrophysics to high altitude flight. This paper describes an application of these forces to a conceptual micro-scale energy harvester, where two possible geometries of operation are described. It is shown that one configuration is significantly simpler to fabricate while the other geometry is more efficient at producing larger forces. The effect of pressure, feature separation, and feature-to-ring gap are analyzed. For consistency and the accurate treatment of the relevant flow conditions, an implementation of the SMOKE code that solves the ES BGK equation was used in all computations. [ABSTRACT FROM AUTHOR]

Numerous reports have established the refrigeration applications of thermoacoustic cooling without compressors and refrigerants. Significant cooling effects can be obtained in a thermoacoustic resonator fitted with a heat exchanging stack and operated at resonance frequency. Past studies, however, have hardly referred to the fundamental relationship between resonant frequency and the resonator geometry. This paper reports the thermoacoustic cooling effects at resonance obtained by changing the diameter of the resonator while holding the length constant and vice versa. Experiments were completed at atmospheric pressure with air as the working fluid using a number of pvc tubes having parallel plate stack from Mylar. The temperature difference measured across the stack showed that a volume increase in the working fluid in general increases the temperature gradient for the quarter-and half-wavelength resonators. Doubling the diameter from 30 mm to 60 mm produced the highest temperature difference due to the greater number of stack plates resulting in a higher overall thermoacaoustic cooling. Increasing the resonator length only produced a small increase in temperature gradient since the resonant frequency at operation is only slightly changed. Investigation on the aspect ratio exhibits no influence on the temperature difference across the stack. This study have shown that the resonator length and diameter do affect the temperature difference across the thermoacoustic stack, and further research should be done to consider the contribution of the stack mass on the overall desired thermoacoustic cooling. [ABSTRACT FROM AUTHOR]

This paper presents an investigation of heat transfer correlation in a falling-film evaporator working with saline water at sub-atmospheric pressures. The experiments are conducted at different salinity levels ranging from 15000 to 90000 ppm, and the pressures were maintained between 0.92 to 2.81 kPa (corresponds to saturation temperatures of 5.9 - 23 0C). The effect of salinity, saturation pressures and chilled water temperatures on the heat transfer coefficient are accounted in the modified film evaporation correlations. The results are fitted to the Han & Fletcher's and Chun & Seban's falling-film correlations which are used in desalination industry. We modify the said correlations by adding salinity and saturation temperature corrections with respective indices to give a better agreement to our measured data. [ABSTRACT FROM AUTHOR]

Hydrogen production from bio-fuels such as bio-ethanol provides significant environmental benefits since the resulted CO2 is consumed again for biomass growth, offering a carbon dioxide neutral energy source. In the actual conditions of increasing energy demand and atmosphere pollution, clean produced hydrogen can be an alternative option for a clean energy vector. In this paper we present the results obtained in hydrogen production by steam reforming of ethanol using oxide supported nickel catalysts. Although Ni is not the most active catalyst for this process, economically is the most attractive one, due to the high price and low availability of noble metals. Ni was dispersed on several oxides: ZrO2, Al2O3, Cr2O3, SiO2 with a target metal concentration of 8 wt%. using impregnation method. The catalysts were characterized using several techniques: N2 adsorption desorption isotherms to determine total surface area and porosity, XRD to determine oxide crystallinity and Ni crystallite size. Each catalyst was tested in steam reforming of ethanol at temperatures ranging from 150 to 350°C, at atmospheric pressure and a ethanol: steam ratio of 1:9. The best ethanol conversion and catalyst stability was obtained for Ni/Al2O3. The catalyst selectivity for H2 production depends on the support nature. The best H2 selectivity was obtained for Ni/ZrO2 catalyst. [ABSTRACT FROM AUTHOR]

The high entropy AlCrFeNiZn alloy was synthesized by high energy ball milling which is a mechanical alloying process and characterized by X-ray Diffraction [XRD]. The crystalline structure of AlCrFeNiZn high entropy alloy mainly consists of BCC structure which can be determined by the angle of peak intensities from the XRD pattern. After 22 h of milling the formation of the HEA was not complete and there existed X-ray intensity peaks corresponding to the elemental powders. Further milling of about 8 h showed an improved result with lesser number of elemental peaks with lower intensities. The 30 h milled AlCrFeNiZn alloy powder was consolidated using compaction unit at a pressure of about 375 MPa for two minutes and is sintered at about 850°C for 2 h at controlled atmosphere. This work attempts to study density, microhardness and microstructures of sintered AlCrFeNiZn high entropy alloy samples studies are done. The density of this HEA alloy is found to be 5.202 g/cm³ at atmospheric pressure and room temperature. The microhardness was found in the Vickers micro hardness scale is 132 HV which is equal to 415 MPa. [ABSTRACT FROM AUTHOR]

We present here a simple coaxial RF vacuum window designed for 200 kW power without any design complicacy and is simple to fabricate. It is achieved by sandwiching a UHV grade ceramic disk in between inner and outer straight conductors. The window has been designed and fabricated for use in the VTL section of ICRF system on ADITYA tokamak. The window has been modeled with CST Microwave Studio and transient analysis has been done for different scattering parameters. The window is found to be an excellent leak tight with leak rate better than 1.0×10-9 mbarl/s. Pressure test on window up to a 3 bar atmospheric pressure shows that it can also be used as a gas barrier in transmission lines. Low power VNA test shows a pleasing VSWR and insertion loss less than 1.07 and 0.05 dB respectively in the frequency range of 20-100MHz. Special care has been taken to minimize sharp edges to avoid pre-breakdown phenomena. Partial discharge tests at 50Hz shows an excellent result up to 24 kV peak and the observed discharge magnitude was less than 20 pC. The window shows the ultra high vacuum compatibility and it tested for high RF power at 29 MHz up to 80kW of power. This paper presents the design detail, tests conducted and the results obtained for the vacuum window. [ABSTRACT FROM AUTHOR]

The paper focuses on the recent progress that has been achieved by the authors through conducting experiments with locally heated shear-driven and falling liquid films. Rupture of the liquid film was investigated and it was found that scenario of film rupture differs widely for different flow regimes. The critical heat flux is about 10 times higher for a shear driven film than that for a falling liquid film, and reaches 250 W/cm2 in experiments with water at atmospheric pressure. Rupture of a subcooled falling liquid film heated from the substrate is preceded by the formation of steady state film surface deformations. The film spontaneously ruptures at the moment when the film thickness in the thinned region reaches a certain critical minimum independent of both the Reynolds number and the plate inclination angle (gravity force). By means of high speed imaging it is found that the process of rupture involves two stages: 1) abrupt film thinning down to a thin residual film; 2) rupture and dryout of the residual film. As the plate inclination angle is reduced the threshold heat flux required for film rupture weakly decreases, however when the angle becomes negative the threshold heat flux begins to rise dramatically, which is associated with an increase of the stabilizing hydrostatic effect due to the growth of the film thickness. [ABSTRACT FROM AUTHOR]

Energy is one of the biggest concerns in the 21st century. In this paper, a new energy harvest method is proposed. The key component of the new method is the Knudsen compressor which is based on the rarefied flow phenomenon of thermal creep. In this study, the possibility of Knudsen compressor filled with nano scale aerogel working at atmosphere pressure is first studied by Direct Simulation Monte Carlo (DSMC) method. The simulation results provide the information for design and fabricate a Knudsen compressor. The numerical analysis estimates that at the day time of summer, an array of multi-stages Knudsen compressor in 1 m2 area could capture energy of 74 W. [ABSTRACT FROM AUTHOR]

This paper describes the new photonic Doppler velocimetry (PDV) technique for measuring time-resolved projectile velocity and acceleration profiles for full flight of the launch package in a two-stage light-gas gun (LGG). This technique is shown to provide excellent temporal and spatial resolution in measurement. Two non-linear acceleration stages were observed for the first time on the LGG. When the gun bore was at atmospheric pressure, a strong opacity was observed during hypervelocity projectile motion >2200 km/s. [ABSTRACT FROM AUTHOR]

Non-thermal atmospheric pressure plasmas have received considerable attention recently. One promising application of non-thermal plasma devices appears to be biomaterial and biomedical treatment. Various biological and medical effects of non-thermal plasmas have been observed by a variety of investigators, including bacteria sterilization, cell apoptosis, and blood coagulation, among others. The mechanisms of the plasma-biomaterial interaction are however only poorly understood. A central scientific challenge is therefore how to answer the question: “What plasma-generated agents are responsible for the observed biological effects?” Our modeling efforts are motivated by this question. In this paper, we review our modeling results of the plasma needle discharge. Then, we address data needs for further modeling and understanding of plasma-biomaterial interaction [ABSTRACT FROM AUTHOR]

In this paper, evaluation of the bacterial inactivation kinetics and the roles of the various plasma agents in the inactivation process will be outlined. In particular, measurements of the plasma temperature, the UV emission, and concentrations of various reactive species (O3, O, OH...) for the special case of air plasma are presented. In addition, the effects of charged particles on bacterial cells are discussed. In this case the cells are modeled as dielectric dust-like particles the surface of which is charged when in contact with the plasma. This charging effect was found to have the potential of causing cell disruption in gram-negative bacteria. [ABSTRACT FROM AUTHOR]

The paper is devoted to studying the dusty plasma created by the injection of dust particles into the atmospheric pressure gas ionized by an electron beam of 85–120 keV energy. The beam current density was varied within 0.1–1.0 mA/cm2. The electron gun operated in the stationary regime. The behavior of dusty particles lighted by a laser “knife” was observed with a digital video camera. Stable plate-like structures were observed in the cathode sheath of non-self-sustained discharge. Numerical simulation was performed by using the non-local model of the non-self-sustained discharge. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The self-sustained thermite reaction between iron oxide (Fe2O3) and aluminum (Al) is commonly slow. This paper presents an experimental study to evaluate the reaction regression rates of these thermite mixtures with or without continuous electrical discharge. Two thermite compositions are tested: stoichiometric (Al2O3 and Fe as the only products) and over aluminized. To generate a fast and stable front propagation in thermite material, a long channel configuration is used and the reaction is assisted with a continuous electrical discharge between two copper plates (external confinement). The reaction velocity is evaluated by the regression rate, which is measured by optical methods. The assisted reaction is compared to the original self-sustained reaction, as a function of the composition. The electrical discharge level is also measured with a current monitor and oscilloscope. The thermodynamic properties of reaction products are predicted by a thermochemical code, named THOR, assuming an isobar adiabatic combustion and using HL equation of state. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]