In this work we have constructed a range gated imaging LIDAR with the aim to show the potential of this
technique as well as to further determine aspects such as the typical energy per pulse needed, the illumination
distribution of the laser source and the safety class. For this, we built a custom frequency doubled nanosecond
pulsed Nd:YAG laser as illumination source, a CCD coupled to a generation II image intensifier and a simple
progressive delays set for the camera gate using a pulse delay generator. At low levels of the illumination pulse
and assuming safety perimeter around the system of approx. 1.5 m, the LIDAR could be classified as class 2M.
In these conditions, we could resolve objects as far as 690 m.
The laser-diode self-mixing technique is a well-known, powerful, very simple and low cost interferometric technique. The typical structure of a laser-diode self-mixing device is made up of a laser-diode, a focusing lens and a processing unit. One can find in literature numerous examples of target displacement, fluid flow, velocity, distance and vibration measurements. Regarding vibration measurements, the self-mixing effect has been mainly applied to measure amplitude and frequency in isolated points but it is difficult to find real applications in which this technique is applied to measure the vibrating behavior of a complete surface. This is due to the different feedback signals that may appear when a laser beam is scattered by a real rough surface. When scanning a surface, the different speckle patterns that contain the feedback signal at different points introduce big changes in the intensity of the scattered signal captured by the photodiode that drives the laser into a strong coupling self-mixing regime with loss of the sinusoidal behavior of the fringes. In many cases, saturation of the photodiode is also found. When this occurs, it is not possible to measure any vibration parameter. By programming simple algorithms, this problem can be overcome. Here we present vibration measurements of titanium tweeter membranes up to 6.8 Khz that show the vibrating behavior in the micrometer range. We demonstrate that the limit in the frequency range is set by the sample frequency of the data acquisition device. Results are compared with different optical techniques for mapping vibrating surfaces such as laser triangulation and electronic speckle pattern interferometry.
This paper presents the results of an investigation about how the vibration of railway vehicles affects nearby buildings. The overall objective is to study the vibration generated in urban environments by tram, train and subway, its transmission to the ground and how the buildings and constructions of the environment receive them.
This paper presents the results of an investigation about the involvement of the tram vibration in nearby buildings. The
overall objective is studying vibration generated in urban environments by tram, transmission to the ground and
receiving them by the constructions of the environment.
Vibrations can generate noise and vibrations in buildings. That is why it is necessary to generate a performance protocol
to characterize the level of vibration affecting rail, road infrastructure and sidewalks and nearby buildings, to assess the
influence of the train (speed , type, profile wheel ,..), rail (area of rolling) and route of step and finally define interim
corrective measures. In this study will be undertaken measures levels (energy) and vibration frequencies of excitement in
route through optical techniques: optical fiber networks with distributed Bragg sensors.
Measuring these vibrations in different configurations constructive allow us to evaluate the suitability of different
sections for different types of uses or environments.
This study aims to help improve the safety of the built environment of a railway operation, in turn increasing the comfort
for passengers and reducing the environmental impact to the environment.
This paper presents the results of an investigation about the involvement of the tram vibration in nearby buildings. The
overall objective is studying vibration generated in urban environments by tram, transmission to the ground and
receiving them by the constructions of the environment.
Vibrations can generate noise and vibrations in buildings. That is why it is necessary to generate a performance protocol
to characterize the level of vibration affecting rail, road infrastructure and sidewalks and nearby buildings, to assess the
influence of the train (speed , type, profile wheel ,..), rail (area of rolling) and route of step and finally define interim
corrective measures. In this study will be undertaken measures levels (energy) and vibration frequencies of excitement in
route through optical techniques: optical fiber networks with distributed Bragg sensors.
Measuring these vibrations in different configurations constructive allow us to evaluate the suitability of different
sections for different types of uses or environments.
This study aims to help improve the safety of the built environment of a railway operation, in turn increasing the comfort
for passengers and reducing the environmental impact to the environment.
We show the basic mechanism of optical pH sensors using hydrogels and FBGs. We show the experimental results
obtained and the importance of a precise formulation of the hydrogel an appropriated design of our transducer.
One of the most interesting points when evaluating the response of an implanted prosthesis is the knowledge of how
biomaterials behave under a certain deforming stress. Obviously, the greater the stress on a particular moment, the higher
possibility of the failure implant. But in many cases, the most important fact regarding the implant failure is due to a
lesser stress that is continuously applied. Therefore it is helpful to know how biomaterials respond to this lesser stress.
Digital speckle interferometry (DSPI) is suitable for this type of determination because of it is a highly sensitive and
non-invasive optical technique.
The aim of the presented work is determining the elasticity of biomaterials such as osseous structures and implants used
to replace bones and to fix fractures between them. In particular, preliminary results were obtained applied to macerated
human radius and a titanium screw used to treat the fractures of this bone. The analysis shows high correlation ratios in
determining Young's modulus via DSPI technique in comparison with than that obtained by creation of the bone
computer aided design (CAD) model using finite element method (FEM) in ANSYS software. The high degree of
concordance between the results of both methods makes it possible to continue studying osseous samples with a fixed
implant, and also other implants made of different alloys.
V. Micó, M. L. Lozano, J. J. Esteve-Taboada, J. A. Carrión, T. Molina-Jiménez, S. Simón, E. Pérez, J. M. Lloris, M. Cruz-Yusta, M. J. López-Tendero, C. Silvestre, F. López, D. Barrera-Villar, R. García-Olcina, S. Sales
There are a lot of factors that call into question the integrity, safety and reliability of concrete macrostructures such as
bridges, buildings, tunnels and dikes. Examples of such factors are humidity variations, in-excess load supported during
years, vibrations and pH variations, which can damage the concrete structure after extended periods. In order to test the
real state of such structures, we present the design and development of fiber optic based sensors that permit the
measurement of loads and tensions applied to the structure, just as both the humidity and pH of the concrete at the
measurement point. The load of the structure can be measured by means of fiber Bragg grating techniques, which
involves wavelength multiplexing and optical spectrum analysis, and the humidity and pH measurements are achieved
by incorporating different types of hydrogels to the nearness of the fiber Bragg grating. The change in humidity and pH
produces volume changes in these hydrogels that modify the spectral response provided by the fiber Bragg grating. Thus,
it is possible to place multiple sensors along the macrostructure to visualize the on-line status during its life time.
Knowledge of how osseous structures and implants behave under deforming stress is an interesting point when evaluating the response of an implanted prosthesis. The failure of an implant is not always due to the great stress a structure may be subjected to at a particular moment, but rather to the effects of deterioration associated with lesser stress but which is continuously applied. Therefore it is helpful to know how bones and implants respond to this lesser stress. Digital speckle interferometry (DSPI) is suitable for this type of determination, as it is a highly sensitive, non-invasive optical technique.
In this study we present the results we obtained when determining the elasticity of a sample of a macerated human radius, a titanium implant and a titanium screw used to treat the fractures of this bone. The correlation ratios we obtained in determining Young's modulus were in the order of r=0.994. Models were made of these structures using the finite elements method (FEM) with the aid of the ANSYS 10.0 program, applying Young's modulus values determined by DSPI.
With a view to monitoring the accuracy of the FEM models of the bone and the implant elements we designed a flexion experiment to obtain the DSPI values in and out of plane. The high degree of concordance between the results of both methods makes it possible to continue studying osseous samples with a fixed implant, and also other implants made of different alloys.
An approximation to the technological needs of the lighting industry is addressed. Typical photometric tests for different
types of luminaries or lighting devices, optical design and simulation processes using specific software, as well as
programmes for luminous simulation in projects and reports produced are presented.
Teresa Molina-Jimenez, Jose Caballero-Aroca, Santiago Simón-Martín, Juan Hervás-Juan, Jose-David García-Martínez, Emilio Pérez-Picazo, Ramón Dolz-García, Alejandro Pons-Vila, Salvador Quintana-Rumbau, Jose Antonio Valiente Pardo, Maria José Estrela, Francisco Pastor-Guzmán
We present results of a R&D project aimed to produce an environmental surveillance system that, working in wild areas, allows for a real-time observation and control of some ambient factors that could produce a natural disaster. The main objective of the project is the development of an open platform capable to work with several kinds of sensors, in order to adapt itself to the needs of each situation. The detection of environmental risks and management of this data to give a real-time response is the overall objective of the project.
The main parts of the system are:
1.- Detection system: capable to perform real-time data and image communication, fully autonomous and designed to consider the environmental conditions.
2.- Alarm management headquaters: reception on real-time of data from the detector network. All the data is analysed to enable a decision about whether there is or not an alarm situation.
3.- Mobile alarm-reception system: portable system for reception of the alarm signal from the headquaters.
The project was financed by the Science and Technology Ministry, National Research and Development Programme (TIC2000-0366-P4, 2001-2004).
We present the definition and development of a three dimensional high precision measurement system for localisation and control of machine tool's drill based on a Michelson-Morley interferometric configuration and a laser tracking subsystem to redirect the measurement beam onto a retro-reflector positioned in the tool nearness. The system measures the retro-reflector position in real time with 5 microns accuracy up to 2 m/s processing material velocities and it is used to carry out an on-line control feedback of the drill position in the machine tool allowing a drill tool replacement during the fabrication process. The system has been integrated and tested in an especially designed machine tool built for this application.
In this paper we present an automatic system for the on-line quality control of printed circuit boards. A line-scan camera permits the acquisition of a 550 mm wide image with a resolution up to 70 microns/pixel. The system detects the following type of errors: cuts and short circuits in tracks, stains, ink excess or faults, pores, omissions, "bites" and track narrowing. The input for the system are just the Gerber data files corresponding to the circuit to be analyzed. All the tolerances and precision factors can be modified directly from the user-friendly interface. For each analyzed board, the type of error detected and its location inside the circuit are indicated in the interface. For each set of analyzed circuits the system provides information for statistical control of the results.
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