Tube Radiation Research Articles

Development of the Method of Calibration Equations for the X-Ray Fluorescence Analysis of Multicomponent Samples in the Presence of Undetectable Elements

New calibration equations are proposed based on the use of intensity ratios of spectral lines and peaks of coherently and incoherently scattered characteristic radiation of an X-ray tube. Prospects for their application to the X-ray fluorescence analysis of samples containing undetectable light elements are shown. The proposed method ensures high precision of determination and performance of analysis in the lack of adequate reference samples. The method was tested on an example of analysis of standard samples of bronze and samples of iron oxide materials.

Investigations on Convective Heat Transfer Enhancement in Circular Tube Radiator Using Al2O3 and CuO Nanofluids

In this study, forced convective heat transfer inside a circular tube automobile radiator is experimentally and numerically investigated. The investigation is carried out using Al2O3 and CuO nanofluids with water as their base fluid. A single radiator circular tube with the same dimensions is numerically modeled. Numerical model is validated using the experimental study results. In the experimental study, Al2O3 and CuO nanofluids of 0.05% volume concentrations (ϕ) were recirculated through the radiator for the Reynolds number (Re) between 260 and 1560. The numerical investigation is conducted for the nanoparticle volume concentration from 0% to 6.0% and 260 < Re < 1560. The investigation shows an enhancement of convective heat transfer coefficient (h) with the increase in nanoparticle volume concentration and with the Reynolds number. A maximum enhancement of 38% and 33% were found for Al2O3 and CuO nanofluids of ϕ = 1% and Re = 1560. For the same cooling load of the radiator, the pumping power can be reduced by 8% and 10%, when Al2O3 and CuO nanofluids (ϕ = 0.8%) were used. Enhancement in convective heat transfer can be utilized to reduce the radiator surface area required. However, the addition of nanofluid results in an enhancement of density (ρ) and viscosity (μ) along with a reduction in specific heat capacity (Cp). Hence, the selection of nanoparticle volume concentration should consider its effect on the thermophysical properties mentioned earlier. It is found that the preferred concentration is between 0.4% and 0.8% for both Al2O3 and CuO nanofluids. In our investigations, it is observed that the convective heat transfer performance of Al2O3 nanofluid is better than the CuO nanofluid.

Improvement of industrial air dehumidification systems by using of ultrasonic vibrations

The results of analytical review of structures and methods for drying dusty moist air in industrial premises are presented, as well as a design of a dehumidifier using ultrasonic vibrations to improve the efficiency of the drying process. The analysis of the aerodynamic mechanism of closed air currents development in dehumidifiers is carried out and the original design of ultrasonic tube radiator is proposed for applying an ultrasonic field to the air flow. The results of vibrational oscillations modelling of an ultrasonic tubular radiator in the regime of radial and radial-bending vibrations are presented. The results of modelling the ultrasonic field shape inside a tubular vibrator are presented. A physical model of ultrasonic cleaning process of moist polluted air is proposed and the results of experimental study of tubular vibrator operation in a flow of moist air are presented.

Choline-amino acid ionic liquids: past and recent achievements about the structure and properties of these really "green" chemicals.

The structure of choline-amino acid ionic liquids, atoxic task-specific solvents composed of materials originated from renewable feedstocks, is reviewed in this letter. The varied and strong interactions that these liquids are capable of establishing are largely dependent on their structure and confer them outstanding solvating properties with respect to a large number of different solutes. Among the experimental methods capable of yielding structural insight, the energy-dispersive version of X-Ray diffraction, that uses the Bremsstrahlung radiation of the X-Ray tube, is a technique very well suited to investigate these liquid systems. The diffraction spectra of five choline-amino acid ionic liquids, recently measured, are reported and discussed; in particular, the presence or absence of the medium-range order pre-peak is related to the presence of polar groups within the amino acid side chain that destroys the hydrophobic interactions between aliphatic chains. In the final section, a recent example of choline-amino acid ionic liquids as for ancient paper preservation and two other interesting results are discussed at the end.

Spectral structure of a polycapillary lens shaped X-ray beam

Polycapillary X-ray optics is widely used in X-ray analysis techniques to create a small secondary source, for instance, or to deliver X-rays to the point of interest with minimum intensity losses [1]. The main characteristics of the analytical devices on its base are the size and divergence of the focused or translated beam. In this work, we used the photon-counting pixel detector ModuPIX to study the parameters for polycapillary focused X-ray tube radiation as well as the energy and spatial dependences of radiation at the focus. We have characterized the high-speed spectral camera ModuPIX, which is a single Timepix device with a fast parallel readout allowing up to 850 frames per second with 256 × 256 pixels and a 55 μm pitch defined by the frame frequency. By means of the silicon monochromator the energy response function is measured in clustering mode by the energy scan over total X-ray tube spectrum.

Study on vortex-induced vibration of the tubes in a nuclear engineering test reactor

The nuclear engineering test reactor in this paper is a small nuclear reactor designed and manufactured in China. The structure of this nuclear reactor is different from the normal pressurized water reactors. Especially, these are some tubes in the nuclear reactor, which are named radiation tube, neutron tube and temperature tube. The vibration induced in the flexible tubes by vortex shedding is practical importance, which is related to the safety of this nuclear reactor. However, it is difficult to obtain the natural frequencies and the dynamic characteristics of the tubes with the undetermined boundary conditions only by numerical analysis. In this paper, a 1/2 scaled-down model of this nuclear reactor was manufactured, and the modal experiment was made to obtain the natural frequencies both in air and in water. Based on the results of the modal test in air and water, the restraint stiffness of the tubes was calculated. Then, CFD analysis was made to calculate the velocities and the vortex shedding frequencies of the flow near the tubes and the vibration equations of the tubes were presented to calculate the dynamic responses of the tubes. A dynamic test was also made to verify the accuracy of the calculation. Compared the results of numerical calculation to the results of dynamic test, it is obvious that the numerical analysis method can reflect the dynamic characteristics of the scaled-down model with a valid margin of error.

Reliability of Nanofluid Concentration on the Heat Transfer Augmentation in Engine Radiator

Nanofluids, the fluid suspensions of nanomaterial, became a promising fluid that is invoked when heat transfer increase is required. Using of nanofluids as a coolant in the engine radiators is a crucial topic for the thermal engines manufactrers due to the expected enhancement in the cooling process. In this study, Two nanofluids (Al2O3/water and CuO/water) flowing in a flat tube of radiator are investigated numerically to evaluate thermal and flow performance. The resizing process for the radiator is performed by using nanofluid instead of water flow. A significant reduction in the radiator volume is achieved due to marked improvement in the heat transfer performance while, the required pumping power after this reduction in the volume is increased over that needed for base fluid. The normalized heat transfer (heat transfer to the pumping power) is found to be a function of both Reynolds number and nanofluid concentration ratio while the ratio of the normalized heat transfer is found to be dependent only on the nanofluid concentration ratio. These dependencies are formulated as general correlations.

Suggestion of the Relative Artifact Index for Noise-independent Evaluation of the Streak Artifact

The aim of this study was to inspect the usefulness of relative artifact index (AIr), which divided artifact index (AI) by standard deviation of the noise image for noise-independent evaluation of the streak artifact in computed tomography images. A water phantom without/with a cylindrical phantom filled with diluted contrast medium was scanned with different tube voltages (100/120/140 kV) and radiation doses (5/10/20 mGy), then images were reconstructed with different kernels (B10/30/50f). AI, location parameter in Gumbel method and AIr were measured in each condition and compared. The higher tube voltage or radiation dose or lower spatial resolution kernel, the lower quantitative values were presented by both AI and Gumbel method. AIr showed quantitative values independent of radiation dose and kernel, and substantial artifact amounts affected only by tube voltage. Our results showed AIr can evaluate quantitative artifact amount independent of image noise.

Effect of Biodiesel and Radiator Tube Heater on Fuel Consumption of Compression Ignition Engine

The growing demand of CI engine for automobiles impacts to the increasing of diesel fuel consumption. The biodiesel fuel and heated fuel in diesel engine are considered as an alternative solution to addres the problems in increasing demand of diesel fuel. This research aims to investigate the effect of adding biodiesel into diesel fuel and fuel heating through a square finned tube in radiator upper tank on fuel consumption in the CI engine. The experimental studies were conducted on 4 cylinder CI engine car using SNI 7554:2010 standard test. The amount of biodiesel added into diesel fuel is varied with a percentage of 0% to 30%. This work also analyzed the effect of different values of the distance between square fin, which are 10 mm, 20 mm, and 30 mm. It can be concluded in this study that incorporating biodiesel in the diesel fuel improves the fuel efficiency. The most efficient consumption is in addition of 15% biodiesel in the amount of 266.7 ml/km. Moreover the fuel heating also affect fuel efficiency of the CI engine. It was found that utilizing a 30 mm square finned tube radiator result in greater fuel consumption rate. Fuel heating can affect the fuel savings resulting from the addition of biodiesel. The most cost-effective consumption is the addition of 20% biodiesel in diesel fuel and heating with 30 mm fin spacing of 206.4 ml/km. By knowing the effect of biodiesel in diesel fuel and fuel heating with the distance between square fin used, it is possible to design an engine system with high fuel efficiency CI engine car.

Determination of mass absorption coefficient in two-layer thin-film Cr/V and V/Cr systems by X-ray fluorescence spectrometry

A method is proposed for the determination of mass absorption coefficient in the analysis of two-layer thin-film V/Cr and Cr/V systems on Polikor substrates by X-ray fluorescence spectrometry. Simply fabricated and unified film layers formed by applying vanadium and chromium on polymer film substrates are used. Correction coefficients taking into account the attenuation of primary radiation of X-ray tube and analytical line of an element from the lower layer in the upper layer are calculated.

Design of a passive safety system for a nuclear thermal rocket

Long-term high payload missions necessitate the need for nuclear space propulsion. Several nuclear reactor types were investigated by the Nuclear Engine for Rocket Vehicle Application (NERVA) program of National Aeronautics and Space Administration (NASA). Study of planned/unplanned transients and their impact on nuclear thermal rockets is important due to the need for long-term missions. It has been determined that a loss-of-flow-accident (LOFA) is the most serious design basis accident that will affect nuclear thermal rockets. A safety system is needed to respond to a LOFA and to prevent the core from melting. In this paper, a special secondary loop has been designed that utilizes the existing components of the Pewee I reactor. In particular, the tie rod tubes are connected to a secondary loop with radiator tubes. A check valve is also present in the circuit to help facilitate natural circulation in one direction in the absence of gravity. The radiator tube heat transfer surface area was increased to the following specifications: (i) 2 times the heat transfer surface area (HTSA) of the tie rod tubes, (ii) 4 times the HTSA of the tie rod tubes, (iii) 6 times the HTSA of the tie rod tubes, (iv) 8 times the HTSA of the tie rod tubes, and (v) 10 times the HTSA of the tie rod tubes. The following expected results were achieved: (i) during both steady-state operation and post-LOFA decay heat removal, temperature of the tie rod can be kept below the material melting point; (ii) during both steady-state operation and post-LOFA decay heat removal, natural circulation can be facilitated with a decent flow rate; (iii) during post-LOFA decay heat removal, the coolant temperatures in the tie rod tubes decreases and the mass flow rate increases; and (iv) in the secondary system, the heat sinks are able to remove the heat generated by the heat sources, during both steady-state and transient operation. As far as minimum radiator HTSA is concerned, the radiator tubes need to have a HTSA of approximately twice of that of the tie rod tubes. This ensures the tie rod tubes won’t melt and there is a decent natural circulation flow rate.

A comparison between transient CFD and FEM simulations of solar central receiver tubes using molten salt and liquid metals

Abstract The design of central receivers in solar thermal power plants is crucial for efficiency and operating behavior of the plant. The local heat flux distribution on the absorber tubes varies, depending on time, weather conditions and aim point strategy. A proper receiver design needs accurate thermodynamic models to detect local temperature distribution, especially hot spots on the absorber tubes. Moreover, due to highly transient boundary conditions, the dynamic behavior of the model is important. Starting with a detailed CFD model of a single receiver tube several simplified FEM models were investigated. The influence of an inhomogeneous heat flux distribution on the absorber and the dynamic behavior after a sudden change of heat flux (e.g. due to passage of clouds) were analyzed. In order to consider radiation exchange between surfaces, simulations with a whole receiver panel were also conducted. The FEM model with one-dimensional fluid elements and constant heat transfer coefficients shows a very good agreement with the detailed CFD model. Further simplifications like the presented model, where the tubes are discretized as projected surfaces are computationally very efficient and can be used for relative comparison between receiver configurations. However, this simplification has deviations in the prediction of tube temperatures and radiation losses. Finally, the receiver simulation of the Solar Two power plant validates the FEM model with the measured data for solar salt. The investigation of liquid metals considers a single tube with an inhomogeneous heat flux on its surface. The detailed analysis shows, that the Nusselt number correlation plays an important role for the tube wall temperature. If the Nusselt number is overestimated in the region of the peak heat flux, the simplified model results in a lower tube wall temperature.

Computed Tomography Experiments on a Laboratory Multipurpose Diffractometer

Applications of soft (Co and Cu X-ray tube) and hard (Ag X-ray tube) radiation in computed tomography experiments on a laboratory X-ray diffractometer are presented. Using low energy (<10 keV) X-ray sources provide the possibility to investigate objects made of light (organic) materials in more detail compared to the high energy application. In case of metal or heavy element containing composites high energy (~20 keV) X-ray sources allow to obtain full 3D information on the samples without destroying them. These measurements allow both qualitative and quantitative analysis of porous materials, samples with oriented components, and solid compounds.

Optical properties of X-ray irradiated Cu<sub>6</sub>PS<sub>5</sub>I-based thin films deposited by magnetron sputtering

Introduction . Cu 6 PS 5 I crystals belong to a big family of compounds with argyrodite structure. They are characterized by high ionic conductivity. That’s why these materials are promising for creation of different type of modern devices such as batteries, supercapacitors, electrochemical sensors, etc. Studies of the influence of external factors on physical properties of Cu 6 PS 5 I materials are important to predict endurance, wear resistance and safety of devices made on their basis. Purpose . The purpose of the paper is to investigate the influence of X-ray irradiation on the optical properties of Cu 6 PS 5 I-based thin films as well as to perform the quantative and qualitative evaluation of the changes that have taken place in the structure “film-substrate” as a result of X-ray irradiation. Methods . Cu 6 PS 5 I-based thin films were deposited onto silicate glass substrates by non-reactive radio frequency magnetron sputtering. The film chemical composition was investigated by energy-dispersive X-ray spectroscopy. X-ray irradiation was performed at different exposition times (30, 60 and 120 min) using wideband radiation of Cu-anode X-ray tube with approx 400 W of power applied (33 kV, 13 mA). Optical transmission spectra of Cu 6 PS 5 I-based thin films were studied using MDR-3 grating monochromator. Results . Optical transmission spectra of X-ray irradiated Cu 5.6 P 1.7 S 4.9 I 0.8 , Cu 6.4 P 1.1 S 4.6 I 0.9 and Cu 8.0 P 0.7 S 3.6 I 0.7 thin films were studied at various irradiation times at room temperature. With irradiation time increase the red shift of the short-wavelength part of transmission spectra and interference maxima is revealed. In the X-ray irradiated thin films the Uhrbach behavior of the optical absorption edge is observed. Optical absorption edge for X-ray irradiated thin films is shifted to the long-wavelength region with irradiation time increase. It leads to the energy pseudogap decrease and Uhrbach energy increase. Dispersion dependences of the refractive index for the X-ray irradiated thin films have shown a slight dispersion of the refractive indices in the transparency region, increasing with approaching the optical absorption edge. With irradiation time increase the nonlinear increase of the refractive indices in the X-ray irradiated thin films is revealed. Conclusions. The influence of X-ray irradiation on optical properties of Cu 6 PS 5 I-based thin films was studied. Changes in optical parameters of the thin films were investigated and described. With irradiation time increase the decrease of energy pseudogap as well as increase of Uhrbach energy and refractive index values was observed. It was determined that with irradiation time increase the darkening and densitification of the thin films occur. The increase of Uhrbach energy indicates on increase of structural disordering induced by the influence of X-ray irradiation.

Experimental and numerical study on heat transfer enhancement of flat tube radiator using Al2O3 and CuO nanofluids

Forced convective heat transfer of Al2O3 and CuO nanofluids through flat tube automobile radiator were studied experimentally and numerically. Nanofluids of 0.05% volume concentrations were prepared with Al2O3 and CuO nanoparticles having diameter below 50 nm. The working fluid recirculates through an automobile flat tube radiator with constant inlet temperature of 90 °C. Experiments were conducted by using water and nanofluids by varying the Reynolds numbers from 136 to 816. The flat tube of the radiator with same dimensions were modeled and numerically studied the heat transfer. The model includes the thickness of tube wall and also considers the effect of fins in the radiator. Numerical studies were carried out for six different volume concentrations from 0.05% to 1% and Reynolds number varied between 136 and 816 for both nanofluids. The results show an enhancement in heat transfer coefficient and effectiveness of radiator with increase in Reynolds number and volume concentration. A maximum enhancement of 13.2% and 16.4% in inside heat transfer coefficient were obtained for 1% concentration of CuO and Al2O3 nanofluids respectively. However increasing the volume concentration causes an increase in viscosity and density, which leads to an increase in pumping power. For same heat rejection of water, the area of the radiator can be reduced by 2.1% and 2.9% by using 1% concentration of CuO and Al2O3 nanofluids respectively. The optimum values of volume concentration were found to be 0.4% to 0.8% in which heat transfer enhancement dominates pumping power increase. Al2O3 nanofluids gives the maximum heat transfer enhancement and stability compared to CuO nanofluids.

Interspecific and intraspecific variation in corolla tube length in Pedicularis species achieved by both cell anisotropy and division

AbstractThe association between plants with long corolla tubes and pollinators with long tongues has evolved repeatedly in diverse pollination systems. However, the morphogenesis of long corolla tubes involved in diverse plant groups remains largely unexplored, limiting our understanding of the evolution and maintenance of long corolla tubes. Corolla tubes of Himalayan Pedicularis species exhibit striking length diversity, ranging from less than 10 mm to more than 120 mm. We investigated the role of cell division and cell expansion in determining the corolla tube morphology in eight Pedicularis species and in an experimental population of P. siphonantha Don in which corolla tubes were elongated under shading and watering treatments. Among species, the corolla tube length was positively correlated with both cell number and cell length but not cell width. Our analyses of intraspecific variation in corolla tube length indicated that it was positively correlated with cell length in all eight species but with cell number in only four of the species, indicating that corolla tube development in Pedicularis generally involves anisotropic cell expansion. The elongation of corolla tubes in P. siphonantha under experimental conditions was caused by the anisotropic elongation of cells; cell number of tube‐elongated flowers was not significantly increased. Our results showed that intraspecific variation in corolla tube length in Pedicularis species was largely attributable to changes in cell anisotropy, but the evolutionary innovation underlying the rapid radiation of Pedicularis corolla tubes was attributable to both cell division and cell expansion.

Investigation of engines radiator heat recovery using different shapes of nanoparticles in H2O/(CH2OH)2 based nanofluids

In this paper, a flat tube of an engine radiator is modeled numerically for improving the cooling process or heat recovery of the engine using nanofluids. Two hydrogen based fluids (water (H2O) and ethylene glycol or EG ((CH2OH)2) and four nanoparticles (CuO, TiO2, Al2O3 and Fe3O4) in different shapes (Brick, Cylindrical, Platelet and Spherical) are considered for modeling the nanofluids in four different Reynolds numbers (500, 1000, 1500 and 2000). Hamilton correlation is used to calculate the thermal conductivity of nanofluids in different shapes of nanoparticles. Furthermore, the effect of nanoparticles volume fraction on the Nusselt number for all nanoparticle shapes is discussed in this study. Results show that EG-TiO2 with platelet shape and larger volume fraction of nanoparticles has the best cooling performance for the engine among other modeled nanofluids.

A comparative study on the total reflection X-ray fluorescence determination of lowZelements using X-ray tube and synchrotron radiation as excitation sources

Detailed total reflection X-ray fluorescence (TXRF) studies for the detection and quantification of low atomic number elements were carried out by using a laboratory dual source TXRF spectrometer equipped with a vacuum chamber and at the International Atomic Energy Agency multi-purpose end-station facility, operated at the XRF beamline of Elettra Sincrotrone Trieste, Italy. Multi-elemental standard aqueous solutions of low Z elements (F, Na, Al, S, K, Sc, and Ti) with different elemental concentrations of 2, 10, 20, and 30 µg/ml were prepared and measured in both setups. The measurements at the synchrotron setup were performed in a scanning mode across the sample residue and perpendicular to the incident beam in order to account properly for a possible non-uniform deposition of certain elements. The accuracy and the detection limits obtained from the TXRF measurements in both setups were determined and comparatively evaluated and assessed. Significant improvement in the TXRF detection limits at the synchrotron beamline end-station was obtained for the elements with Z ≤ 13 (Al). Copyright © 2017 John Wiley & Sons, Ltd.

Experimental Investigation of Laminar Convection Heat Transfer of Al2O3-Ethylene Glycol-Water Nanofluid as a Coolant in a Car Radiator

In this experimental study, heat transfer of a coolant nanofluid, obtained by adding alumina nanoparticles to Ethylene Glycol-water (60:40 by mass), in a car radiator has been investigated. For this purpose, an experimental setup has been designed and constructed. Firstly, to investigate the accuracy of the results, the experiments have been done for the base fluid. Then the experiments have been performed for the nanofluid with different nanoparticles volume fractions of 0.003, 0.006, 0.009 and 0.012. To ensure laminar flow regime three coolant flow rates of 9, 11 and 13 lit/min have been tested. The thermophysical properties have been calculated using the recently presented temperature dependent models in the literature. According to the results, both the convective heat transfer coefficient and Nusselt number increase (about 9%) with increasing the coolant flow rate. Also, convective heat transfer coefficient increases with increasing the nanoparticles volume fraction. Although Nusselt number decreases when nanofluid is utilized, it enhances as the nanoparticles volume fraction increases. Based on the experimental results obtained, A new empirical correlation has been developed for average Nusselt number of Al2O3-EG-water nanofluid in developing region of flat tubes of car radiator for laminar flow and its maximum error is 3%.

The use of the ratios of intensities of spectral lines for X-ray fluorescence analysis of metal alloys and oxide materials

An X-ray fluorescence analysis technique is proposed, which is based on using ratios of intensities of spectral lines. The technique includes performing calculations for evaluation of calibration equations, which allows using few reference samples or carrying out standardless analysis, if necessary. That parameters of the calibration equations depend linearly on concentrations of disturbing elements allows one to simplify taking their influence into account. To apply the developed technique to analysis of samples containing a significant amount of undetectable light elements, a use of a dependence of intensity ratio of the characteristic radiation of the X-ray tube’s anode, coherently and incoherently scattered by a sample, on a total content of undetectable elements is proposed. The technique’s adequacy is demonstrated by analysis of standard steel samples, metal cuttings and iron-ore materials.