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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]

The extensive consumption of aluminum, combined with the shortage of the existing raw materials, and particularly bauxite, necessitates the exploitation of alternative raw materials for the production of alumina. The present paper focuses on the possible use of kaolin, as an abundant, cheap and high-aluminum content raw material, in alumina production, via the application of the Aranda-Mastin technology in the leaching step. From this point of view, leaching experiments were conducted on untreated kaolin and thermally treated, metakaolin, applying atmospheric pressure, temperature of 90 °C and with an aqueous solution of a low HCl concentration as the leaching agent. Leaching, in the aforementioned conditions, is an industrially applied process, characterized by highly efficient aluminum dissolution in the case of metakaolin with low silicon dissolution at a short retention time, but with respectively lower achieved results for untreated kaolin. In order to raise the aluminum dissolution rate from untreated material, temporal and subsequently chemical intensification was applied. The analysis indicated a higher aluminum dissolution rate, up to 70%, with the application of a high acid concentration of leaching agent, performed for a long retention time that could be further improved. [ABSTRACT FROM AUTHOR]

The effects of climate change are now evident on a global level and indisputable even to the most skeptical. Melting ice, rising sea levels, and changing climate zones are a daily occurrence and subject of debate in the media. Beyond the obvious effects of these phenomena on human lives, countless others arise and await being studied. Meanwhile, it has been proven that many health problems are related to changes in weather and large fluctuations of temperature. Specifically, studies have been conducted to correlate the rupture of intracranial aneurysms with seasonal and climatic conditions. The conclusions of these studies linked the rupture of intracranial aneurysms with higher temperatures, as well as with higher atmospheric pressure. Inevitably, one of the questions raised is whether the change in weather brings about conditions that favor the rupture of intracranial aneurysms throughout the year. The purpose of this paper is to present the results of studies that correlate these two factors and, then, to demonstrate that these meteorological conditions now prevail throughout the year, influencing, perhaps, and distributing the rupture of intracranial aneurysms during all seasons. [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]

Safety valves under operating have a backpressure value, which is working on the safety valves outlet area. If this backpressure value is higher than the 10% from safety valves set pressure then the safety valves will not working safety. In this paper, will be shown how can calculate and simulate this backpressure value when only one safety valve is working and when two safety valve are working at the same time and they venting in a common pipe system. It will also be presented, what is the effect of corrosion in the venting pipeline on backpressure. [ABSTRACT FROM AUTHOR]

Water flowing on a sprinkled tube bundle forms three basic modes: It is the Droplet mode (liquid drips from one tube to another), the Jet mode (with an increasing flow rate droplets merge into a column) and the Membrane (Sheet) mode (with further increasing of falling film liquid flow rate columns merge and create sheets between the tubes. With sufficient flow rate sheets merge at this state and the tube bundle is completely covered by a thin liquid film). There are several factors influencing the individual mode types as well as heat transfer. Beside the above mentioned falling film liquid flow rate they are for instance tube diameters, tube pitches in a tube bundle or a physical condition of a falling film liquid. This paper presents a summary of data measured at atmospheric pressure at a tube bundle consisting of copper tubes of 12 milimeters diameter and of the studied tube length one meter. The tubes are positioned horizontally one above another with the tested pitches of 15, 20, 25 and 30 mm and there is a distribution tube placed above them with water flowing out. The thermal gradient of 15-40 has been tested with all pitches where the falling film liquid's temperature at the inlet of the distribution tube was 15 °C. The liquid was heated during the flow through the exchanger and the temperature of the sprinkled (heater) liquid at the inlet of the exchanger with a constant flow rate about 7.2 litres per minute was 40 °C. The tested flow of the falling film liquid ranged from 1.0 to 13.0 litres per minute. Sequences of 180 exposures have been recorded in partial flow rate stages by thermographic camera with record frequency of 30 Hz which were consequently assessed using the Matlab programme. This paper presents results achieved at the above mentioned pitches and at three types of tube bundle surfaces. [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]

The article is dedicated to the study of hydrometeorological parameters on a stationary oceanographic platform in the Black Sea. The research paper contains the description developed in the Marine Hydrophysical Institute’s complex for measuring meteorological parameters (wave height, wind speed and direction, free-air and sea temperature, barometric pressure, relative humidity). The measurements were carried out on a stationary oceanographic platform located in the coastal zone of the southern coast of Crimea at a distance of 600 m from the shore. The wind speed and direction sensor was located at a height of 21 m, the sampling resolution was 0.2 Hz. The wind speed was reduced from 21 m to the standard height of observation by the formula assuming the existence of a logarithmic sublayer. The sensors of atmospheric pressure, relative air humidity, air temperature were located at a height of 13 m, the sampling resolution was 1 Hz. The depth of immersion of the water temperature sensor was 1-1.5 m. As a result of the analysis of more than 70,000 hour records of meteorological parameters during 2011-2020, the regime and extreme characteristics for the study area were estimated. The average monthly wind speed in summer is approximately 4.5-4.9 m/s, and in winter – 6.2-6.6 m/s. The maximum wind speeds on the SOP reached values of 19-26 m/s, and gusts – 39 m/s. The average monthly air temperature varies from 7.4 ⁰С in February to 25.6⁰С in August. The average annual humidity is 71%. The average monthly temperature of sea water varies from 10.1 ⁰С in February-March to 23.7⁰С in August. Seasonal variation is present in the average monthly values of the atmospheric pressure: the lowest values (1006.4 hPa) are observed in July and the highest (1016.2 hPa) - in December. [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 article is dedicated to the study of hydrometeorological parameters on a stationary oceanographic platform in the Black Sea. The research paper contains the description developed in the Marine Hydrophysical Institute’s complex for measuring meteorological parameters (wave height, wind speed and direction, free-air and sea temperature, barometric pressure, relative humidity). The measurements were carried out on a stationary oceanographic platform located in the coastal zone of the southern coast of Crimea at a distance of 600 m from the shore. The wind speed and direction sensor was located at a height of 21 m, the sampling resolution was 0.2 Hz. The wind speed was reduced from 21 m to the standard height of observation by the formula assuming the existence of a logarithmic sublayer. The sensors of atmospheric pressure, relative air humidity, air temperature were located at a height of 13 m, the sampling resolution was 1 Hz. The depth of immersion of the water temperature sensor was 1-1.5 m. As a result of the analysis of more than 52,000 hour records of meteorological parameters during 2011-2018, the regime and extreme characteristics for the study area were estimated. The average monthly wind speed in summer is approximately 4.6-4.8 m/s, and in winter – 6-6.5 m/s. The maximum wind speeds on the SOP reached values of 19-26 m/s, and gusts – 39 m/s. The average monthly air temperature varies from 7.3 ºС in February to 25.6ºС in August. The average annual humidity is 73%. The average monthly temperature of sea water varies from 10.1 ºС in February-March to 23.7 ºС in August. Seasonal variation is present in the average monthly values of the atmospheric pressure: the lowest values (1006.1 hPa) are observed in July and the highest (1016.1 hPa) - in December. [ABSTRACT FROM AUTHOR]

The paper deals with height determination in indoor environment using inertial sensors (accelerometers, gyroscopes) and barometer built in a smartphone, which is very important to detect upstairs and downstairs motion of the users. The algorithm proposed uses the barometric formula for height determination and the relationship between the decreasing barometric pressure and increasing height. The main advantage of the use of barometer is the long-term accuracy, because the algorithm is not recursive. The problem of the barometric measurement lies in the local disturbances of barometric pressure which is caused by temperature changes (increasing temperature cause increase of the pressure) and instable air mass (air-conditioning cause inhomogeneous air mass). These local disturbances of the barometric pressure lead to increase of errors in height determination. Reduce the errors caused by the temperature change, accelerometer data using step detection with average step height (without integration process), are used. Double integration of the acceleration measured is used only in specific situations (only in case when elevator is used during the movement). The benefit of the use of combined processing of barometer and accelerometer data against the use of only barometer or accelerometer data is analyzed on the base of experimental measurements. [ABSTRACT FROM AUTHOR]

Using different gasification agents: air and steam, two types of gasification process were performed into a batch reactor at temperature of 750°C and 850°C and atmospheric pressure. The only difference between of the two compared experimental configurations was represented by the gasification agent used in the process. The amount of oxygen introduced into the reactor for air gasification at an ER of 0.3 was computed. Therefore, in the steam gasification process, the same amount of oxygen was introduced, so establishing an unordinary steam to biomass ratio. In this way, the two processes, air vs. steam gasification, were compared, the rest of the process parameters being kept constant. This paper approaches the transitory regimes (initiation stage) of gasification process in order to observe the influence of process temperature and gasification agent on the process run. According to the experimental results, better gas quality is obtained if steam is used as a gasifying agent, yet the conversion and energy efficiencies decreases. By optimizing time residence in steam gasification, process efficiencies may be increased. [ABSTRACT FROM AUTHOR]

University small satellites are now routinely launched into space with the NASA ELaNa program, the AFOSR University Nanosatellite Program (UNP), and the NSF CubeSat program. As part of these programs, undergraduate students have developed several small satellites and many High Altitude Research Platform (HARP) balloon experiments. Student outcomes include augmenting ABET objectives a-k, new ways of enhancing STEM education and undergraduate research, improving publications/resumes, internships and jobs. In this paper we review over 15 years of undergraduate education developing a number of small satellites. We present case studies on the precursor High Altitude Research Platform (HARP) and two satellites that were deployed in orbit. These two satellites and over 350 HARP student launches to the edge of space (only 2% of earth's atmosphere pressure at 30km altitude) are examples of challenging projects which, when managed properly, can have a magnificent educational, practical, and societal impact. Various teaching pedagogy and assessment data are included so that interested groups can begin their own programs. [ABSTRACT FROM AUTHOR]

The paper describes results of analysis of pool boiling heat transfer on enhanced surfaces. Two types of structural surfaces were used: open micro-channel surfaces consisting of a system of parallel microchannels 0.3 mm wide, from 0.2 to 0.5 mm deep and with a pitch of 0.6 mm, and plain micro-fins 0.5 mm in height, uniformly spaced on the base surface with a spacing from 0.6 to1.5 mm. Pool boiling data at atmospheric pressure were obtained for saturated water, ethanol and FC-72. The effects of microchannel/ micro-fin dimensions on heat transfer coefficient in nucleate pool boiling were examined. Substantial enhancement of heat transfer coefficient was observed. [ABSTRACT FROM AUTHOR]

The paper presents experimental investigations into pool boiling heat transfer for open microchannel surfaces. Parallel microchannels fabricated by machining were about 0.3 mm wide, and 0.2 to 0.5 mm deep and spaced every 0.1 mm. The experiments were carried out for ethanol, and FC-72 at atmospheric pressure. The image acquisition speed was 493 fps (at resolution 400 x 300 pixels with Photonfocus PHOT MV-D1024-160-CL camera). Visualization investigations aimed to identify nucleation sites and flow patterns and to determine the bubble departure diameter and frequency at various superheats. The primary factor in the increase of heat transfer coefficient at increasing heat flux was a growing number of active pores and increased departure frequency. Heat transfer coefficients obtained in this study were noticeably higher than those from a smooth surface. [ABSTRACT FROM AUTHOR]

The article is dedicated to the study of hydrometeorological parameters on a stationary oceanographic platform in the Black Sea. The research paper contains the description developed in the Marine Hydrophysical Institute's complex for measuring meteorological parameters (wave height, wind speed and direction, free-air and sea temperature, barometric pressure, relative humidity). The measurements were carried out on a stationary oceanographic platform located in the coastal zone of the southern coast of Crimea at a distance of 600 m from the shore. The wind speed and direction sensor was located at a height of 21 m, the sampling resolution was 0.2 Hz. The wind speed was reduced from 21 m to the standard height of observation by the formula assuming the existence of a logarithmic sublayer. The sensors of atmospheric pressure, relative air humidity, air temperature were located at a height of 13 m, the sampling resolution was 1 Hz. The depth of immersion of the water temperature sensor was 1-1.5 m. As a result of the analysis of more than 33,000 hour records of meteorological parameters during 2011-2017, the regime and extreme characteristics for the study area were estimated. The average monthly wind speed in summer is approximately 4.8 m/s, and in winter - 6-6.4 m/s. The maximum wind speeds on the SOP reached values of 19- 26 m/s, and gusts - 40 m/s. The average monthly air temperature varies from 7.3 °C in February to 25 °C in August. The average annual humidity is 72%. The average monthly temperature of sea water varies from 10.1 °C in February-March to 23.6 °C in August. Seasonal variation is present in the average monthly values of the atmospheric pressure: the lowest values (1006.4 hPa) are observed in July and the highest (1016.9 hPa) - in December. [ABSTRACT FROM AUTHOR]

The results of experimental study of evolution of temperature fields under single vapor bubble obtained by high-speed infrared thermometry with high spatial resolution (13 μm) are presented in this paper. The data were obtained at pool boiling of saturated ethanol and deionized water at atmospheric pressure. Reconstruction of local instantaneous heat flux distribution on the heater surface was carried out with the use of numerical simulation. It is shown that maximal local heat flux was observed in the microlayer region on the bubble growth stage and reached the value an order of magnitude greater than the input heat flux. Based on the results of experimental and numerical researches the estimations of the microlayer thickness were carried out at pool boiling of water and ethanol, which are in good agreement with the experimental data presented in the literature and obtained using laser interferometry. [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]

Human interest in meteorological domain has been manifested since ancient times, when scientists began to observe and describe the weather and have tried to explain most of the weather phenomena. Science in 2007 at North University of Baia Mare is continuously registered meteorological data with Oregon Scientific WMR 100 weather station type. It can follow the climatic parameters continuously from the urban area and microclimates. Recorded weather data are displayed on the main console; it has the possibility to connect to a computer and through a program allows unlimited recording of the data. Recorded weather variables are temperature indoor/outdoor, humidity indoor/outdoor, wind speed and direction, average monthly rainfall, daily, annual, atmospheric pressure, dew point temperature, the cooling produced by wind, temperature index and more. The main aim of this paper is to survey the environment for application meteoinformatics importance of projects and for ecological research. As we know, it is necessary to extend the perspectives in studying of Environment Information Systems (EISs) integrated in the urban ambient problematic. Meteoinformatic systems became usable in terms of research recently, but their efficiency and ease of use has led to an increasing rate of their use. As prospects for the future would be to create a computerized network through which to connect personal weather stations, obtaining valuable information from several regions of the country and can, thus clearly distinguish details of the mezoclimate of each region. [ABSTRACT FROM AUTHOR]

Two cold Argon atmospheric pressure plasma jets were generated based on the form of DBD configuration device. One device equipped with one powered ring electrodes as well as a grounded ring electrode, and the other's grounded electrode was a metal plate. The characteristics of two different plasma jets with mid-frequency sinusoidal power were measured in this paper. The waveforms of the applied voltage and discharge current, Lissajous figures, images and optical spectrum of DBD were acquired, when Ar was inlet. The transported charges, discharge power and electron excitation temperature were investigated through Lissajous figures. Moreover, the optical emission spectroscopy is used to measure the plasma parameters, of which the electronic excitation temperature is determined by the Boltzmann's plot method using seven characteristic lines of Ar. The experimental results indicate that, discharge power and electronic excitation temperature of two plasma jets increase with the applied voltage. Through investigating the two plasma jets' electricity and optical characteristics, it was found that, compared to one plasma jet generated by the device with a grounded ring electrode, the other plasma jet generated by the device with a grounded metal-plate electrode had smaller discharge power but higher electron excitation temperature when under the same applied voltage and Ar flow rate. [ABSTRACT FROM PUBLISHER]

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]

Testing and certification of explosion-proof electrical equipment required for product conformity assessment are extremely important, taking into account the unexpected hazard of explosion occurrence due to potentially explosive atmospheres generated by mixtures of air-gas/dust. The explosion risk has to be minimized in order to ensure the health and safety of people and for preventing material damages. The new European Directive which regulates the protection to explosion field is the ATEX Directive 2014/34/EU which covers equipment and protective systems intended for use in potentially explosive atmospheres. The Directive replaces the previous Directive 94/9/EC, it defines the essential health and safety requirements and conformity assessment procedures, to be applied before products are placed on the EU market. According to the regulations and specific standards in force, electrical equipment used in potentially explosive atmospheres have to be subject to various tests, according to their destination. The impact resistance test is performed on a specific test stand, and it is a qualitative type of test. The paper presents an improvement of this type of test, by adding a force cell and by measuring, recording and analyzing (using specific software) the forces which are generated over the equipment tested. Several equipment, with different types of protection to explosion, used in industries with potentially explosive atmospheres, other than mines (ie. oil&gas industry) are subjected to this quantitative type of test. Results obtained from the physical test analysis will be used for calibrating computational simulations of the impact resistance test, which will represent a useful tool for further analysis performed on equipment and protective systems intended for use in potentially explosive atmospheres. [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]

The phenomenon of phase change is one of the most important contemporary issues of thermal engineering. In particular, this applies to all kinds of heat exchanger systems, which should achieve the highest possible efficiency while reducing investment and operating costs. Some of these systems are heat pipes or thermosyphons, which, among others, are used for the heat transfer, temperature stabilization and the regulation of heat flux density. Additionally, they are passive systems, and therefore do not require an external power supply. Heat pipes can be used to stabilize the surface temperature of roads and driveways. Large heat tubes can be applied for heating the surface of bridges and overpasses, which become icy in unfavorable climatic conditions. The paper presents research on the test facility, whose main component is a long vertical copper fin. The temperature at the base of the fin was kept constant for a given series of measurements. Heat receiving fluid was ethanol at atmospheric pressure. The measurement methodology and the results of investigations were discussed. The surface temperature distribution was measured with the infrared camera, and on this basis the local values of heat flow and the heat transfer coefficient were determined. The results were presented as boiling curves for both the fin with the smooth surface and the one covered with a metal capillary-porous structure. The results obtained are useful in the design of heat exchangers, including passive heating of the ground. [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]

In the construction of precision seeders, different types of seed-metering devices are used, which differ both from a constructive point of view and also from the point of view of the principle of distribution. This paper presents the factors influencing the seeding precision of seeders for weeding plants, as well as the forces acting on the discharge of seeds in the distribution process of precision seeders. [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]