scholarly journals The Evaluation of the Damping Characteristics of a Hard Coating on Titanium

2007 ◽  
Vol 14 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Christopher Blackwell ◽  
Anthony Palazotto ◽  
Tommy J. George ◽  
Charles J. Cross
Keyword(s):  
Aspect Ratio ◽  
Turbine Blades ◽  
Plate Thickness ◽  
Point Of View ◽  
Internal Stresses ◽  
Experimental Point ◽  
Laser Vibrometer ◽  
The Past ◽  
Damping Characteristics ◽  
Bending Mode

Engine failures due to fatigue have cost the Air Force an estimated $400 million dollars per year over the past two decades. Damping treatments capable of reducing the internal stresses of fan and turbine blades to levels where fatigue is less likely to occur have the potential for reducing cost while enhancing reliability. This research evaluates the damping characteristics of magnesium aluminate spinel, MgO+Al2O3, (mag spinel) on titanium plates from an experimental point of view. The material and aspect ratio were chosen to approximate the low aspect ratio blades found in military gas turbine fans. In the past, work has generally been performed on cantilever supported beams, and thus the two-dimensional features of damping were lost. In this study plates were tested with a cantilevered boundary condition, using electrodynamic shaker excitation. The effective test area of each specimen was 4.5 in × 4.5 in. The nominal plate thickness was 0.125 in. Mag spinel was applied to both sides of the plate, at a thickness of 0.01 in, and damping tests were run at room temperature. The effect of the coating was evaluated at the 2nd bending mode (mode 3) and the chord wise bending mode (mode 4). A scanning laser vibrometer revealed the frequency and shape of each mode for the plates. Sine sweeps were used to characterize the damping of the coated and uncoated specimens for the modes tested. The coating increased damping nonlinearly for both modes tested in which the general outcome was similar to that found in beams.

scholarly journals Bending Response and Energy Absorption of Closed-Hat-Section Beams

2016 ◽  
Vol 10 (11) ◽  
pp. 225
Author(s):  
Hafizan Hashim ◽  
Amir Radzi Ab Ghani ◽  
Wahyu Kuntjoro
Keyword(s):  
Energy Absorption ◽  
Plate Thickness ◽  
Point Of View ◽  
Critical Parameters ◽  
Research Report ◽  
Experimental Point ◽  
Fe Model ◽  
Research Information ◽  
Foam Filling ◽  
Energy Absorbers

Many articles on bending collapse but not limited to closed-hat-section beams have been reported mainly from experimental point of view but less in simulation-based approach. Detailed investigation on critical parameters of closed-hat-section beams to examine their energy absorption capability is also less found in the literature. This paper presents the procedure for development and validation of a finite element (FE) model of a closed-hat-section beam under quasi static three-point bending using an explicit nonlinear FE technique. Developed FE models were validated through comparison with existing and present experiment results. Firstly, the existing models were rebulit via present modeling technique using informations provided in the relevant research report. Simulation results of rebuilt model were compared with existing results for verification and validation. Next, to further validate the present model, actual physical experiment replicating the FE model was set up for comparison of results. Validated models were then used in parametric studies in order to investigate the effect of some critical parameters such as plate thickness, flange and web width, and foam filler. Results show that the wall thickness, web width, and filler have direct effect on bending stiffness. Foam filling indicated significant enhancement on the crush and energy absorption of closed-hat-section beams. This study provides detail procedures and research information which will facilitate improvisation of current design as well as the design of foam filled closed-hat-section beams as energy absorbers in impact applications.

An Experimental Investigation of the Dynamics of a Blade With Two Under-Platform Dampers

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Daniele Botto ◽  
Chiara Gastadi ◽  
Muzio M. Gola ◽  
Muhammad Umer
Keyword(s):  
Tangential Force ◽  
Turbine Blades ◽  
Relative Displacement ◽  
Point Of View ◽  
Test Rig ◽  
New Approach ◽  
Ground Support ◽  
The Past ◽  
Force Components ◽  
Blade Frequency

Several experimental apparatuses have been designed in the past to evaluate the effectiveness of under-platform dampers. Most of these experimental setups allow to measure the overall damper efficiency in terms of reduction of vibration amplitude in turbine blades. The experimental data collected with these test rigs do not increase the knowledge about the damper dynamics, and therefore, the uncertainty on the damper behavior remains a big issue. In this paper, a different approach to evaluate the damper–blade interaction has been put forward. A test rig has been purposely designed to accommodate a single blade and two under-platform dampers. One side of each damper is in contact with a ground support specifically designed to measure two independent forces on the damper. In this way, both the normal and the tangential force components in the damper–blade contact can be inferred. Damper kinematics is rebuilt by using the relative displacement measured between damper and blade. This paper describes the concept behind the new approach, shows the details of the new test rig, and discusses the blade frequency response from a new point of view.

scholarly journals The Influence of Gravity Loads on the Seismic Design of RBS Connections

2014 ◽  
Vol 8 (1) ◽  
pp. 248-261 ◽  
Author(s):  
R. Montuori
Keyword(s):  
Seismic Design ◽  
Experimental Tests ◽  
Point Of View ◽  
Experimental Point ◽  
Reduced Beam Section ◽  
The Past ◽  
Analytical Point ◽  
Intermediate Section ◽  
Beam Section ◽  
Rbs Connections

Connections with Reduced Beam Section (RBS) have been investigated in the last 20 years both from an analytical point of view and from an experimental point of view. Several experimental tests demonstrated that RBS connections designed according to themost modern seismic codes are able to obtain the desired goal: the protection of the connection due to the yielding of the adjacent RBS. But in all the past researches and experimental tests the role that vertical loads can play was neglected or not properly accounted for. This study proposes a new procedure for accurately computing the relation between RBS location, vertical load and amount of section reduction for ensuring that plastic hinges develop in the reduced sections or in a reduced section and in an intermediate section of the beam.

scholarly journals A Survey on Anti-Spoofing Methods for Facial Recognition with RGB Cameras of Generic Consumer Devices

2020 ◽  
Vol 6 (12) ◽  
pp. 139
Author(s):  
Zuheng Ming ◽  
Muriel Visani ◽  
Muhammad Muzzamil Luqman ◽  
Jean-Christophe Burie
Keyword(s):  
Facial Recognition ◽  
Critical Issue ◽  
Attack Detection ◽  
Point Of View ◽  
Future Research ◽  
Experimental Point ◽  
Survey Paper ◽  
The Past ◽  
Consumer Devices ◽  
Presentation Attack Detection

The widespread deployment of facial recognition-based biometric systems has made facial presentation attack detection (face anti-spoofing) an increasingly critical issue. This survey thoroughly investigates facial Presentation Attack Detection (PAD) methods that only require RGB cameras of generic consumer devices over the past two decades. We present an attack scenario-oriented typology of the existing facial PAD methods, and we provide a review of over 50 of the most influenced facial PAD methods over the past two decades till today and their related issues. We adopt a comprehensive presentation of the reviewed facial PAD methods following the proposed typology and in chronological order. By doing so, we depict the main challenges, evolutions and current trends in the field of facial PAD and provide insights on its future research. From an experimental point of view, this survey paper provides a summarized overview of the available public databases and an extensive comparison of the results reported in PAD-reviewed papers.

Programme for Experiments on Thinking

1950 ◽  
Vol 2 (4) ◽  
pp. 145-152 ◽  
Author(s):  
F. C. Bartlett
Keyword(s):  
Point Of View ◽  
Experimental Point ◽  
Gap Filling ◽  
The Past ◽  
Thinking Process ◽  
High Level ◽  
Design Experiments

In remembering, items are used in the form in which they are alleged to have been perceived at some time in the past. In thinking, however, evidence is given and the essential character of the process is to move beyond this evidence, but in line with it, to something for which so far, no exact or complete perceptual basis is claimed. From an experimental point of view the best approach is to consider thinking as a high level skill, and to design experiments in the light of what has been discovered during recent years about the learning, practice and achievements of skill on a psycho-motor level. When this is done, it turns out that the thinking process can usefully be considered as one in which gaps are filled up in accord with specific evidence provided. The fundamental gap-filling processes are either of interpolation or of extrapolation. In the present paper the methodology proposed is developed and illustrated in a preliminary manner.

Chelovek.RU/Человек.RU

Chelovek RU ◽  
2020 ◽  
pp. 18-53
Author(s):  
Sergei Avanesov ◽  
Keyword(s):  
Family History ◽  
Great Distance ◽  
Point Of View ◽  
The Past ◽  
Russian Philosopher ◽  
True Meaning ◽  
The Future ◽  
Pavel Florensky ◽  
The Moment

Abstract. The article analyzes the autobiography of the famous Russian philosopher, theologian and scientist Pavel Florensky, as well as those of his texts that retain traces of memories. According to Florensky, the personal biography is based on family history and continues in children. He addresses his own biography to his children. Memories based on diary entries are designed as a memory diary, that is, as material for future memories. The past becomes actual in autobiography, turns into a kind of present. The past, from the point of view of its realization in the present, gains meaning and significance. The au-thor is active in relation to his own past, transforming it from a collection of disparate facts into a se-quence of events. A person can only see the true meaning of such events from a great distance. Therefore, the philosopher remembers not so much the circumstances of his life as the inner impressions of the en-counter with reality. The most powerful personality-forming experiences are associated with childhood. Even the moment of birth can decisively affect the character of a person and the range of his interests. The foundations of a person's worldview are laid precisely in childhood. Florensky not only writes mem-oirs about himself, but also tries to analyze the problems of time and memory. A person is immersed in time, but he is able to move into the past through memory and into the future through faith. An autobi-ography can never be written to the end because its author lives on. However, reaching the depths of life, he is able to build his path in such a way that at the end of this path he will unite with the fullness of time, with eternity.

Portuguese Sardines - from the ritual to the brand

2017 ◽  
Vol 5 (2) ◽  
pp. 109-120
Author(s):  
Cecília Avelino Barbosa
Keyword(s):  
Social Construction ◽  
Place Branding ◽  
Symbolic Capital ◽  
City Council ◽  
Point Of View ◽  
City Branding ◽  
The Past ◽  
Behavioral Expression ◽  
The City ◽  
City Identity

Place branding is a network of associations in the consumer’s mind, based on the visual, verbal, and behavioral expression of a place. Food can be an important tool to summarize it as it is part of the culture of a city and its symbolic capital. Food is imaginary, a ritual and a social construction. This paper aims to explore a ritual that has turned into one of the brands of Lisbon in the past few years. The fresh sardines barbecued out of doors, during Saint Anthony’s festival, has become a symbol that can be found on t-shirts, magnets and all kinds of souvenirs. Over the year, tourists can buy sardine shaped objects in very cheap stores to luxurious shops. There is even a whole boutique dedicated to the fish: “The Fantastic World of Portuguese Sardines” and an annual competition promoted by the city council to choose the five most emblematic designs of sardines. In order to analyze the Sardine phenomenon from a city branding point of view, the objective of this paper is to comprehend what associations are made by foreigners when they are outside of Lisbon. As a methodological procedure five design sardines, were used of last year to questioning to which city they relate them in interviews carried in Madrid, Lyon, Rome and London. Upon completion of the analysis, the results of the city branding strategy adopted by the city council to promote the sardines as the official symbol of Lisbon is seen as a Folkmarketing action. The effects are positive, but still quite local. On the other hand, significant participation of the Lisbon´s dwellers in the Sardine Contest was observed, which seems to be a good way to promote the city identity and pride in their best ambassador: the citizens.

High-Tc superconductors from the experimental point of view

1988 ◽  
Vol 156 (9) ◽  
pp. 117-135 ◽  
Author(s):  
L.P. Gor'kov ◽  
N.B. Kopnin
Keyword(s):  
Point Of View ◽  
Experimental Point

Equilibrium Profile of Modern Belted Radial Ply Tires: Its Determination and Performance Benefits

2013 ◽  
Vol 41 (2) ◽  
pp. 127-151
Author(s):  
Rudolf F. Bauer
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Finite Element Methods ◽  
Mathematical Analysis ◽  
Internal Stresses ◽  
Stress Concentrations ◽  
Equilibrium Profiles ◽  
Equilibrium Profile ◽  
And Performance ◽  
Beneficial Property

ABSTRACT The benefits of a tire's equilibrium profile have been suggested by several authors in the published literature, and mathematical procedures were developed that represented well the behavior of bias ply tires. However, for modern belted radial ply tires, and particularly those with a lower aspect ratio, the tire constructions are much more complicated and pose new problems for a mathematical analysis. Solutions to these problems are presented in this paper, and for a modern radial touring tire the equilibrium profile was calculated together with the mold profile to produce such tires. Some construction modifications were then applied to these tires to render their profiles “nonequilibrium.” Finite element methods were used to analyze for stress concentrations and deformations within all tires that did or did not conform to equilibrium profiles. Finally, tires were built and tested to verify the predictions of these analyses. From the analysis of internal stresses and deformations on inflation and loading and from the actual tire tests, the superior durability of tires with an equilibrium profile was established, and hence it is concluded that an equilibrium profile is a beneficial property of modern belted radial ply tires.

History of Tour de France from the Geographical Point of View

2013 ◽  
Vol 22 (3-4) ◽  
pp. 255-277 ◽  
Author(s):  
Vladimír Bačík ◽  
Michal Klobučník
Keyword(s):  
Point Of View ◽  
The Past ◽  
Advanced Technologies ◽  
The World ◽  
Spatial Dimensions ◽  
Tour De France ◽  
Wide Circle ◽  
History Of ◽  
Expert Community ◽  
Geographical Point

Abstract The Tour de France, a three week bicycle race has a unique place in the world of sports. The 100th edition of the event took place in 2013. In the past of 110 years of its history, people noticed unique stories and duels in particular periods, celebrities that became legends that the world of sports will never forget. Also many places where the races unfolded made history in the Tour de France. In this article we tried to point out the spatial context of this event using advanced technologies for distribution of historical facts over the Internet. The Introduction briefly displays the attendance of a particular stage based on a regional point of view. The main topic deals with selected historical aspects of difficult ascents which every year decide the winner of Tour de France, and also attract fans from all over the world. In the final stage of the research, the distribution of results on the website available to a wide circle of fans of this sports event played a very significant part (www.tdfrance.eu). Using advanced methods and procedures we have tried to capture the historical and spatial dimensions of Tour de France in its general form and thus offering a new view of this unique sports event not only to the expert community, but for the general public as well.

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