scholarly journals Experimental setup for investigating the dynamics of the ascent of a cluster of bubbles in a liquid

2018 ◽  
Vol 194 ◽  
pp. 01005
Author(s):  
Vladimir Arkhipov ◽  
Sergey Basalaev ◽  
Sergey Orlov ◽  
Sergey Polenchuk
Keyword(s):  
Room Temperature ◽  
Experimental Setup ◽  
Bubble Cluster ◽  
Air Bubble ◽  
The Given ◽  
Compact Cluster

There is a scheme of experimental setup providing preparation of the compact cluster of monodispersed bubbles of the given diameter presented in the work. Further, in this research we have calculated setup parameters that are necessary for preparation of the compact air bubble cluster in glycerin at room temperature.

scholarly journals An experimental study of the dynamics of ascent of the bubble system in the presence of a surfactant

2018 ◽  
Vol 194 ◽  
pp. 01002
Author(s):  
Alexandra Antonnikova ◽  
Sergey Basalaev ◽  
Anna Usanina ◽  
Eugene Maslov
Keyword(s):  
Experimental Study ◽  
Reynolds Numbers ◽  
Experimental Setup ◽  
Bubble Cluster ◽  
Bubble System ◽  
Wide Range ◽  
Compact Cluster ◽  
Glycerol Medium

This paper presents investigations on the new experimental setup for obtaining a compact cluster of monodisperse bubbles of a given diameter is presented. Also we provided the results of experimental study of the bubble cluster floating-up in the presence of a surfactant in a wide range of Reynolds numbers. There was held a comparison of the dynamics of the floating-up of a monodisperse bubble cluster in a glycerol medium and in the medium glycerin supplemented with a surfactant.

Pressure dependent ultrasonic properties of hcp hafnium metal

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ramanshu P. Singh ◽  
Shakti Yadav ◽  
Giridhar Mishra ◽  
Devraj Singh
Keyword(s):  
Elastic Constants ◽  
Pressure Range ◽  
Room Temperature ◽  
Ultrasonic Attenuation ◽  
Coupling Constants ◽  
Ultrasonic Properties ◽  
Acoustic Coupling ◽  
Third Order Elastic Constants ◽  
The Stability ◽  
The Given

Abstract The elastic and ultrasonic properties have been evaluated at room temperature between the pressure 0.6 and 10.4 GPa for hexagonal closed packed (hcp) hafnium (Hf) metal. The Lennard-Jones potential model has been used to compute the second and third order elastic constants for Hf. The elastic constants have been utilized to calculate the mechanical constants such as Young’s modulus, bulk modulus, shear modulus, Poisson’s ratio, and Zener anisotropy factor for finding the stability and durability of hcp hafnium metal within the chosen pressure range. The second order elastic constants were also used to compute the ultrasonic velocities along unique axis at different angles for the given pressure range. Further thermophysical properties such as specific heat per unit volume and energy density have been estimated at different pressures. Additionally, ultrasonic Grüneisen parameters and acoustic coupling constants have been found out at room temperature. Finally, the ultrasonic attenuation due to phonon–phonon interaction and thermoelastic mechanisms has been investigated for the chosen hafnium metal. The obtained results have been discussed in correlation with available findings for similar types of hcp metals.

The formation of iron(III) oxide hydroxides from iron(II) oxalate

1976 ◽  
Vol 29 (10) ◽  
pp. 2149 ◽  
Author(s):  
RJ Atkinson
Keyword(s):  
Sodium Hydroxide ◽  
Intermediate Product ◽  
Room Temperature ◽  
Oxidation Process ◽  
Solid Phase ◽  
Bubble Flow ◽  
Air Bubble ◽  
Dissolved Iron ◽  
Complete Reaction ◽  
Iron Concentrations

FeC2O4,2H2O(s) suspensions in sodium hydroxide solutions were oxidized by a fast air-bubble flow at room temperature until complete reaction had occurred. With amounts of NaOH in the range OH/Fe initial mole ratio ≤1.0, the reaction is FeC2O4, 2H2(s)+ OH-(aq)+ �O2(g) → ⅔γFeOOH(s)+1/3Fe(C2O4)33-(aq)+13/6H2O With OH/Fe mole ratio ≥ 2.0 the reaction is FeC2O4, 2H2(s)+ 2OH-(aq)+ �O2(g) → αFeOOH(s)+(C2O4)33-(aq)+ 5/2 H2O Mixtures of goethite (α-FeOOH) and lepidocrocite (γ-FeOOH) form at intermediate OH/Fe mole ratio. The oxidation process occurs in a solid-phase intermediate product. Comparisons with similar oxidations of iron(11)sulphate solutions showed that γ-FeOOH formation was favoured and α-FeOOH formation inhibited in the iron(11) oxalate oxidation. These differences are related to pH and dissolved iron concentrations.

Vibrational analysis of the low resolution absorption spectra of BrClCS and Br2CS

1988 ◽  
Vol 66 (3) ◽  
pp. 359-366 ◽  
Author(s):  
B. Simard ◽  
R. P. Steer ◽  
R. H. Judge ◽  
D. C. Moule
Keyword(s):  
Absorption Spectra ◽  
Room Temperature ◽  
Vibrational Analysis ◽  
Vibrational Frequencies ◽  
Low Resolution ◽  
Barrier Heights ◽  
Vibrational Levels ◽  
Out Of Plane ◽  
The Given

The [Formula: see text] absorption spectra of BrClCS and Br2CS have been photographed under low resolution at room temperature. The electronic origins of BrClCS and Br2CS have been placed at 17116 and 16859 cm−1, respectively. Vibronic analyses show that the molecules are non-planar in their ā states. By fitting quadratic–Gaussian and quadratic–quartic double-minimum potentials to the observed vibrational levels of the out-of-plane manifolds, the equilibrium out-of-plane angles and the barrier heights to molecular inversion have been estimated to be 25 ± 1 deg and 541 ± 10 cm−1 for BrClCS, and 17.5 ± 1 deg and 524 ± 10 cm−1 for Br2CS. In the case of BrClCS, all six ā state vibrational frequencies have been obtained. In the case of Br2CS, only modes 1 (C—S stretch), 2 (symmetric C—Br stretch), 3 (in-plane Br—C—Br scissor), and 4 (out-of-plane bend) are active in the spectrum. Comparisons with other tetraatomic thiocarbonyls support the given assignments.

Novel Concept of Experimental Setup for Characterisation of Plastic Yielding of Sheet Metal at Elevated Temperatures

2005 ◽  
Vol 6-8 ◽  
pp. 657-664 ◽  
Author(s):  
Manfred Geiger ◽  
G. van der Heyd ◽  
Marion Merklein ◽  
Wolfgang Hussnätter
Keyword(s):  
Sheet Metal ◽  
Material Properties ◽  
Room Temperature ◽  
Stress Condition ◽  
Elevated Temperatures ◽  
Biaxial Stress ◽  
Experimental Setup ◽  
Special Importance ◽  
Plastic Yielding ◽  
Novel Concept

In times of highest significance of process modelling and numerical simulation characterisation of material properties is of special importance for tools’ and components’ dimensioning. But in general material properties depend on many different influencing variables, e.g. temperature, humidity and many others. Especially in fields of sheet metal forming the mechanical behaviour of components highly differs according to real stress condition. In particular yield loci combine the information of beginning of yielding with a biaxial stress condition, but nevertheless for many materials they have not been determined yet. For all others the existing values are available only at room temperature. In this paper a novel concept of the experimental setup is shown, with which plastic yielding of sheet metal can be examined also at elevated temperatures. In usual biaxial tension tests cruciform specimen are drawn in plane. The new machine-concept, which is presented in this paper, is based on a punch-load moving perpendicular to the sheet. By clamping the specimen restoring forces are induced, which cause in dependence of special developed tool and work piece geometries defined stress conditions. Using an optical measurement system for determination of strains with CCDcameras of very high frame rate allows exact identification of starting plastification by offline analysis. Experiments at elevated temperatures are realised by local heating with a diode laser and a special optical system to reach a homogenous distribution of temperatures in the forming zone. On the one hand these investigations are necessary for many materials to achieve further information on characteristic properties in warm forming, because their data are only known at room temperature. On the other hand some materials, e.g. magnesium wrought alloys, are mostly formed at elevated temperatures (here in the range of 200°C to 250°C), because of its significant higher formability. Thus, material behaviour must be characterised at these temperatures.

Investigation upon Mechanical Properties of Thin Film Silicon Under Cryogenic Temperature

2004 ◽  
Vol 851 ◽  
Author(s):  
Yi Zhao ◽  
Xin Zhang
Keyword(s):  
Thin Film ◽  
Cryogenic Temperature ◽  
Room Temperature ◽  
Cooling System ◽  
Michelson Interferometer ◽  
Experimental Setup ◽  
Good Match ◽  
Silicon Thin Film ◽  
Micro Raman Spectroscopy ◽  
Thin Film Silicon

ABSTRACTThin film silicon material has an extensive application in cooling satellite instrumentation under cryogenic environment. The performance and reliability of the cooling system heavily depends on mechanical behavior of the thin films. In this paper, we built an experimental setup and used compressive gas to actuate a silicon thin film under both room temperature and cryogenic temperature. The elastic modulus was derived from the film's deflection using laser Michelson interferometer. Stress distribution was obtained using Micro Raman spectroscopy. It was found that Young's modulus derived from the deflection increases with decreasing temperature. Compressive stress concentrated at edge centers of the film and tensile stress occurred at the center. There is a good match between the theoretical predications and experimental observations.

Functional oxide films with engineered ferroelectric properties

2013 ◽  
Vol 1507 ◽  
Author(s):  
R. Wördenweber ◽  
T. Ehlig ◽  
J. Schubert ◽  
R. Kutzner ◽  
E. Hollmann
Keyword(s):  
Electric Field ◽  
Room Temperature ◽  
Dipole Moments ◽  
Ferroelectric Properties ◽  
Field Direction ◽  
Complex Dielectric Constant ◽  
Electric Field Direction ◽  
Relaxation Experiments ◽  
Polar Nanoregions ◽  
The Given

ABSTRACTThe ferroelectric properties of anisotropically strained SrTiO3 films are analyzed by detailed measurements of the complex dielectric constant as function of temperature, frequency, bias voltage and electric field direction. The strain induces a relaxor-ferroelectric phase that persists up to room temperature. However, transition temperature and ferroelectric properties strongly depend on the orientation of the electric field and therefore on the amount of structural strain in the given electric field direction. Frequency and time dependent relaxation experiments reveal the presence and properties of polar nanoregions with randomly distributed directions of dipole moments in the film.

Mild and efficient conversion of trifluoromethylarenes into tribromomethylarenes using boron tribromide

2009 ◽  
Vol 63 (1) ◽  
Author(s):  
Hongbiao Chen ◽  
Jianxiang Yin ◽  
Yuanbin Lin
Keyword(s):  
Room Temperature ◽  
Reaction Conditions ◽  
Efficient Conversion ◽  
Boron Tribromide ◽  
The Given

AbstractTribromomethylarenes were prepared efficiently, at room temperature, from trifluoromethylarenes with boron tribromide as the brominating reagent. The present process is applicable to the preparation of various substituted benzotribromide derivatives from substituted benzotrifluoride compounds. p-Substituted benzotrifluoride compounds were found to be more reactive than o-substituted isomers under the given reaction conditions.

scholarly journals Evaluating the Usefulness of Unsupervised Monitoring in Cultural Heritage Monuments

2021 ◽  
Author(s):  
Charalampos Zafeiropoulos ◽  
Ioannis N. Tzortzis ◽  
Ioannis Rallis ◽  
Eftychios Protopapadakis ◽  
Nikolaos Doulamis ◽  
...  
Keyword(s):  
Cultural Heritage ◽  
Performance Metrics ◽  
Ground Truth ◽  
Hyperspectral Images ◽  
Experimental Setup ◽  
Clustering Methods ◽  
Clustering Techniques ◽  
Monitoring Applications ◽  
The Given

In this paper, we scrutinize the effectiveness of various clustering techniques, investigating their applicability in Cultural Heritage monitoring applications. In the context of this paper, we detect the level of decomposition and corrosion on the walls of Saint Nicholas fort in Rhodes utilizing hyperspectral images. A total of 6 different clustering approaches have been evaluated over a set of 14 different orthorectified hyperspectral images. Experimental setup in this study involves K-means, Spectral, Meanshift, DBSCAN, Birch and Optics algorithms. For each of these techniques we evaluate its performance by the use of performance metrics such as Calinski-Harabasz, Davies-Bouldin indexes and Silhouette value. In this approach, we evaluate the outcomes of the clustering methods by comparing them with a set of annotated images which denotes the ground truth regarding the decomposition and/or corrosion area of the original images. The results depict that a few clustering techniques applied on the given dataset succeeded decent accuracy, precision, recall and f1 scores. Eventually, it was observed that the deterioration was detected quite accurately.

scholarly journals Simulation and Experimental Verification of the Thermal Behaviour of Self-Written Waveguides

2021 ◽  
Vol 11 (17) ◽  
pp. 7881
Author(s):  
Axel Günther ◽  
Murat Baran ◽  
Wolfgang Kowalsky ◽  
Bernhard Roth
Keyword(s):  
Room Temperature ◽  
Optical Transmission ◽  
Numerical Aperture ◽  
Heating Process ◽  
Experimental Setup ◽  
Experimental Measurements ◽  
Curing Time ◽  
Material Parameters ◽  
Time Changes ◽  
Increasing Temperature

In this work, we investigated the optical response of a self-written waveguide (SWW) in detail by heating the structure from room temperature up to 60 °C. Previous results indicated a decrease in the optical transmission with increasing temperature for certain waveguide parameters. Based on new experimental measurements, we have identified material parameters resulting in opposite behaviour. An experimental setup was conceived to verify these results. Hereby, we were able to show that we can adjust material parameters such as refractive index and the corresponding density of the material by adapting the curing time applied during the fabrication of the waveguides. This, in turn, affects the material’s response during the heating process. We showed that a limitation of the external curing time changes the internal conditions of the SWW and the cladding in a manner that the numerical aperture increases with the temperature, which subsequently also results in an increase in the optical transmission. In this study, we explain this unexpected behavior of the SWW and point towards possible future applications.

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