scholarly journals Static and Dynamic Experimental Analysis of the Galloping Stability of Porous H-Section Beams

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
F. Gandia ◽  
J. Meseguer ◽  
A. Sanz-Andrés
Keyword(s):  
Cross Flow ◽  
Industrial Applications ◽  
Geometrical Parameters ◽  
Smoke Visualization ◽  
Surface Pressure Distribution ◽  
Prismatic Beam ◽  
Visualization Techniques ◽  
Limiting Case ◽  
Static Criterion ◽  
Insight Into

The phenomenon of self-induced vibrations of prismatic beams in a cross-flow has been studied for decades, but it is still of great interest due to their important effects in many different industrial applications. This paper presents the experimental study developed on a prismatic beam with H-section. The aim of this analysis is to add some additional insight into the behaviour of the flow around this type of bodies, in order to reduce galloping and even to avoid it. The influence of some relevant geometrical parameters that define the H-section on the translational galloping behaviour of these beams has been analysed. Wind loads coefficients have been measured through static wind tunnel tests and the Den Hartog criterion applied to elucidate the influence of geometrical parameters on the galloping properties of the bodies under consideration. These results have been completed with surface pressure distribution measurements and, besides, dynamic tests have been also performed to verify the static criterion. Finally, the morphology of the flow past the tested bodies has been visualised by using smoke visualization techniques. Since the rectangular section beam is a limiting case of the H-section configuration, the results here obtained are compared with the ones published in the literature concerning rectangular configurations; the agreement is satisfactory.

scholarly journals 3D-Printed Multilayer Sensor Structure for Electrical Capacitance Tomography

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3416 ◽  
Author(s):  
Aleksandra Kowalska ◽  
Robert Banasiak ◽  
Andrzej Romanowski ◽  
Dominik Sankowski
Keyword(s):  
Industrial Applications ◽  
Industrial Test ◽  
Electrical Capacitance Tomography ◽  
Geometrical Parameters ◽  
Electrical Capacitance ◽  
Low Contrast ◽  
Sensor Structure ◽  
Internal Measurement ◽  
3D Printed ◽  
Capacitance Tomography

Presently, Electrical Capacitance Tomography (ECT) is positioned as a relatively mature and inexpensive tool for the diagnosis of non-conductive industrial processes. For most industrial applications, a hand-made approach for an ECT sensor and its 3D extended structure fabrication is used. Moreover, a hand-made procedure is often inaccurate, complicated, and time-consuming. Another drawback is that a hand-made ECT sensor’s geometrical parameters, mounting base profile thickness, and electrode array shape usually depends on the structure of industrial test objects, tanks, and containers available on the market. Most of the traditionally fabricated capacitance tomography sensors offer external measurements only with electrodes localized outside of the test object. Although internal measurement is possible, it is often difficult to implement. This leads to limited in-depth scanning abilities and poor sensitivity distribution of traditionally fabricated ECT sensors. In this work we propose, demonstrate, and validate experimentally a new 3D ECT sensor fabrication process. The proposed solution uses a computational workflow that incorporates both 3D computer modeling and 3D-printing techniques. Such a 3D-printed structure can be of any shape, and the electrode layout can be easily fitted to a broad range of industrial applications. A developed solution offers an internal measurement due to negligible thickness of sensor mount base profile. This paper analyses and compares measurement capabilities of a traditionally fabricated 3D ECT sensor with novel 3D-printed design. The authors compared two types of the 3D ECT sensors using experimental capacitance measurements for a set of low-contrast and high-contrast permittivity distribution phantoms. The comparison demonstrates advantages and benefits of using the new 3D-printed spatial capacitance sensor regarding the significant fabrication time reduction as well as the improvement of overall measurement accuracy and stability.

Exploring genomes with a game engine

2014 ◽  
Vol 169 ◽  
pp. 443-453 ◽  
Author(s):  
Jeremiah J. Shepherd ◽  
Lingxi Zhou ◽  
William Arndt ◽  
Yan Zhang ◽  
W. Jim Zheng ◽  
...  
Keyword(s):  
Real Time ◽  
Video Game ◽  
Linear Structure ◽  
Structural Data ◽  
Game Engine ◽  
3D Genome ◽  
Genome Viewer ◽  
A Genome ◽  
Visualization Techniques ◽  
Insight Into

More and more evidence indicates that the 3D conformation of eukaryotic genomes is a critical part of genome function. However, due to the lack of accurate and reliable 3D genome structural data, this information is largely ignored and most of these studies have to use information systems that view the DNA in a linear structure. Visualizing genomes in real time 3D can give researchers more insight, but this is fraught with hardware limitations since each element contains vast amounts of information that cannot be processed on the fly. Using a game engine and sophisticated video game visualization techniques enables us to construct a multi-platform real-time 3D genome viewer. The game engine-based viewer achieves much better rendering speed and can handle much larger amounts of data compared to our previous implementation using OpenGL. Combining this viewer with 3D genome models from experimental data could provide unprecedented opportunities to gain insight into the conformation–function relationships of a genome.

scholarly journals Discovery of Fe7O9: a new iron oxide with a complex monoclinic structure

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Ryosuke Sinmyo ◽  
Elena Bykova ◽  
Sergey V. Ovsyannikov ◽  
Catherine McCammon ◽  
Ilya Kupenko ◽  
...  
Keyword(s):  
Applied Sciences ◽  
Crystal Structure ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Industrial Applications ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Pressure High Temperature ◽  
Insight Into

Abstract Iron oxides are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary iron oxide with the hitherto unknown stoichiometry of Fe7O9. This new oxide was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 adopts a monoclinic C2/m lattice with the most distorted crystal structure among the binary iron oxides known to date. The synthesis of Fe7O9 opens a new portal to exotic iron-rich (M,Fe)7O9 oxides with unusual stoichiometry and distorted crystal structures. Moreover, the crystal structure and phase relations of such new iron oxide groups may provide new insight into the cycling of volatiles in the Earth’s interior.

Estimation of the Time Delay Associated With Damping Controlled Fluidelastic Instability in a Normal Triangular Tube Array

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
John Mahon ◽  
Craig Meskell
Keyword(s):  
Time Delay ◽  
Cross Flow ◽  
Fluid Forces ◽  
Fluidelastic Instability ◽  
Order Of Magnitude ◽  
Sample Frequency ◽  
Pitch Ratio ◽  
Parameterized Model ◽  
Semi Empirical ◽  
Insight Into

Fluidelastic instability (FEI) produces large amplitude self-excited vibrations close to the natural frequency of the structure. For fluidelastic instability caused by the damping controlled mechanism, there is a time delay between tube motion and the resulting fluid forces but magnitude and physical cause of this is unclear. This study measures the time delay between tube motion and the resulting fluid forces in a normal triangular tube array with a pitch ratio of 1.32 subject to air cross-flow. The instrumented cylinder was forced to oscillate in the lift direction at three excitation frequencies for a range of flow velocities. Unsteady surface pressures were monitored with a sample frequency of 2 kHz at the mid plane of the instrumented cylinder. The instantaneous fluid forces were obtained by integrating the surface pressure data. A time delay between the tube motion and resulting fluid forces was obtained. The nondimensionalized time delay was of the same order of magnitude assumed in the semi-empirical quasi-steady model (i.e., τ2 = 0.29 d/U). Although, further work is required to provide a parameterized model of the time delay which can be embedded in a model of damping controlled fluidelastic forces, the data already provides some insight into the physical mechanism responsible.

scholarly journals Current perspective on production and applications of microbial cellulases: a review

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Nisha Bhardwaj ◽  
Bikash Kumar ◽  
Komal Agrawal ◽  
Pradeep Verma
Keyword(s):  
Critical Factor ◽  
Industrial Sector ◽  
Industrial Applications ◽  
Cellulolytic Enzymes ◽  
Promising Tool ◽  
The Status ◽  
Key Enzyme ◽  
Increasing Demand ◽  
Immobilization Techniques ◽  
Insight Into

AbstractThe potential of cellulolytic enzymes has been widely studied and explored for bioconversion processes and plays a key role in various industrial applications. Cellulase, a key enzyme for cellulose-rich waste feedstock-based biorefinery, has increasing demand in various industries, e.g., paper and pulp, juice clarification, etc. Also, there has been constant progress in developing new strategies to enhance its production, such as the application of waste feedstock as the substrate for the production of individual or enzyme cocktails, process parameters control, and genetic manipulations for enzyme production with enhanced yield, efficiency, and specificity. Further, an insight into immobilization techniques has also been presented for improved reusability of cellulase, a critical factor that controls the cost of the enzyme at an industrial scale. In addition, the review also gives an insight into the status of the significant application of cellulase in the industrial sector, with its techno-economic analysis for future applications. The present review gives a complete overview of current perspectives on the production of microbial cellulases as a promising tool to develop a sustainable and greener concept for industrial applications.

Flow Dynamics Over Two Cylinders in Tandem Subjected to Different Heating Cases

2021 ◽  
Author(s):  
Rami Homsi ◽  
MD Islam ◽  
Yap Yit Fatt ◽  
Isam Janajreh
Keyword(s):  
Heat Transfer ◽  
Cross Flow ◽  
Temperature Fields ◽  
Circular Cylinders ◽  
Transfer Coefficients ◽  
Extended Body ◽  
Heat Transfer Coefficients ◽  
Velocity Magnitude ◽  
Fluid Properties ◽  
Limiting Case

Abstract Heated and unheated flows with forced convection over two fixed circular cylinders in tandem are studied numerically for 80 ≤ Re ≤ 250 and 1 ≤ T* ≤ 2.3. Three different spacing ratios (L/D) = [2, 4, 8] are considered under three heating conditions. The scenarios considered are (1) heated upstream and unheated downstream cylinders, (2) unheated upstream and heated downstream cylinders and (3) heated upstream and downstream cylinders. These scenarios represent the limiting case for a cross-flow heat exchanger, where the downstream tubes are at increasingly lower or higher temperature for cooling or heating, respectively. The global aerodynamic forces on the cylinder as vortices shed was investigated. The flow is visualized by plotting the streamlines, temperature fields, and velocity magnitude contours for the different spacing ratios and compared to the flow regimes in literature namely, Extended-body, Reattachment, and Co-shedding regimes. The drag and surface heat transfer coefficients are analyzed for different scenarios. The effect of heating on the fluid properties and the resulted wakes in the flow are found to be strongly influenced by Re and L/D. The scenario of heated upstream and unheated downstream cylinders was found to increase the mean drag coefficient Cd on the upstream cylinder for L/D = 2 & 4 but is not as evident for the downstream cylinder. The heat transfer coefficient h on the upstream cylinder remained approximately the same regardless of a heated or unheated downstream cylinder. In contrast, h of the downstream cylinder decreases for the scenario of heated upstream and downstream cylinder.

Feature Visualization

1997 ◽  
Author(s):  
Jan Wouter Versluis ◽  
Willem F. Bronsvoort ◽  
Klaas Jan de Kraker ◽  
Kees Seebregts
Keyword(s):  
Feature Model ◽  
Feature Models ◽  
New Techniques ◽  
Additional Information ◽  
Model Image ◽  
Feature Geometry ◽  
Engineering Information ◽  
Visualization Techniques ◽  
Insight Into ◽  
Feature Visualization

Abstract New techniques for visualizing feature models are presented. These do not only provide better geometric and spatial model insight than the standard display techniques, but also functional insight into a feature model by visualizing engineering information. Geometry is visualized by combining shaded and line visualization techniques, resulting in clearer images. Among the engineering information that is visualized are feature intersections, closure faces and feature parameters. This is done by explicitly displaying feature geometry instead of the geometry of the final shape only, and by displaying additional information in a model image. Combined, these techniques provide powerful possibilities to visualize feature models. The implementation uses specified feature and camera properties and a cellular geometric datastructure for generating images. The cellular data structure contains the feature geometry information required for feature visualization.

Parametric Investigation of the Flow-Sound Interaction Mechanism for Single Cylinders in Cross-Flow

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Omar Afifi ◽  
Atef Mohany
Keyword(s):  
Heat Exchangers ◽  
Interaction Mechanism ◽  
Cross Flow ◽  
Acoustic Resonance ◽  
Industrial Applications ◽  
Resonance Excitation ◽  
Acoustic Damping ◽  
Radiation Losses ◽  
Cylinder Diameter ◽  
Tube Bundles

Abstract Flow-excited acoustic resonance is a design concern in many industrial applications. If not treated, it may lead to excessive vibrational loads, which could subsequently result in premature structural failure of critical equipment. For the case of tube bundles in heat exchangers, several acoustic damping criteria were proposed in the literature to predict the occurrence of resonance excitation. However, these criteria, in some cases, are not reliable in differentiating between the resonant and nonresonant cases. A primary reason for that is the geometrical differences between reduced scale models and full-scale tube bundles, and their effect on the flow-sound interaction mechanism. Therefore, the effect of two geometrical aspects, namely, the duct height and the cylinder diameter, on the self-excited acoustic resonance for single cylinders in cross-flow is experimentally investigated in this work. Changing the duct height changes the natural frequency of the excited acoustic modes and the duct's acoustic damping and radiation losses. Changing the cylinder diameter changes the flow velocity at frequency coincidence, the pressure drop, and Reynolds number. It is found that increasing the duct height decreases the acoustic impedance, which makes the system more susceptible to resonance excitation. This, in turn, changes the magnitude of the acoustic pressure at resonance, even for cases where the dynamic head of the flow is kept constant. The acoustic attenuation due to visco-thermal losses is quantified theoretically using Kirchhoff's acoustical damping model, which takes into account the geometrical aspects of the different ducts. Results from the experiments are compared with the acoustic damping criteria from the literature for similar cases. It is revealed that the height of the duct is an important parameter that should be included in damping criteria proposed for tube bundles of heat exchangers, as it controls the acoustic damping and radiation losses of the system, which have been over-looked in the past.

Numerical simulation of nonlinear thermal radiation on the 3D flow of a couple stress Casson nanofluid due to a stretching sheet

2020 ◽  
pp. 1-28
Author(s):  
P. V. Satya Narayana ◽  
Tarakaramu Nainaru ◽  
G. Sarojamma ◽  
Isaac Lare Animasaun
Keyword(s):  
Heat Transfer ◽  
Couple Stress ◽  
Three Dimensional ◽  
Casson Fluid ◽  
Industrial Applications ◽  
Physical Parameters ◽  
Nonlinear Thermal Radiation ◽  
Scaling Analysis ◽  
Nonlinear Odes ◽  
Limiting Case

Abstract Little is known on the three-dimensional flow of couple stress Casson fluid conveying nanoparticles when the significance of Lorentz force, chaotic gesture of those minute particles and thermophoresis are significant. The intent of this investigation is to focus on the flow of such fluid along a horizontal surface due to dual stretching and internal heating. The dimensional nonlinear equations are reduced into a system of coupled nonlinear ODEs employing scaling analysis and later they are solved numerically. The results are discussed graphically for various emerged physical parameters through different plots. The results in the absence of stretching ratio factor indicate that the heat absorption parameter and Prandtl number accelerate the heat transfer rate. The temperature of the non- Newtonian couple stress fluid is found to be bigger than that of viscous case. It may be suggested that Casson couple stress nanofluid can be substituted for the corresponding viscous fluid in industrial applications for greater heat transfer. The outcomes are closely matched with the studies available in the literature as a limiting case.

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