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This paper shows the authors experience in the implementation of cooperative learning during the fourth year of the Mechanical Engineering Grade, having involved from the second to the fourth year. Difficulties encountered are discussed.

The economic crisis that began in Spain at the end of 2007 and early 2008, which still lasts today, has greatly harmed industry in the country. Many companies dissolved, and many workers who worked for them remained unemployed. But what effect did the financial crisis have on universities? Apart from financial problems, they generally have had an increase in the number of students enrolled. Many of them are people who, after becoming unemployed, have decided to take time to improve their academic standing, and thus have more chances of finding a job when they finish. This paper will show how these people, with their knowledge and experience acquired in industry as workers, can add value to the manufacturing processes class.

The ultimate purpose of a conveniently located university campus in an industrial zone is to train future workers that can nurture existing companies in the county or region. There must be, therefore, a strong relationship between companies and universities; but unfortunately, for various reasons, this is not happening in many countries nowadays. The present work is going to study a particular case: Campus of Alcoy of the Universtitat Politècnica de Valencia, as an example of university located in an industrial area. This example can be extrapolated to any European region away from a major city and heavy industrialization. The results of a recent study in which both agents got involved are showed.

At the Alcoy Campus of the Universitat Politècnica de València, we were challenged to obtain the first double degree for our campus. This double degree was established for a Mechanical Engineering major, and our partner institution was Ostfalia Hochschule für Angewandte Wissenschaften, located in Wolfenbüttel campus. The agreement between the schools was signed in 2012, after three years of work. Students from either university could get an official diploma in Mechanical Engineering at both universities if they spent two consecutive semesters in the partner institution. This has many benefits for students and professors, which will be discussed in this paper, along with the main process followed to arrive to the final agreement.

An alternative to the traditional can manufacturing process is to use plastic laminated rolled steels as base stocks. This material consist of pre-heated steel coils that are sandwiched between one or two sheets of polymer. The heated sheets are then immediately quenched, which yields a strong bond between the layers. Such polymer-coated steels were investigated by Jaworski [1, and Sellés [, and found to be suitable for ironing with carefully controlled conditions. A novel multi-layer polymer coated steel has been developed for container applications. This material presents an interesting extension to previous research on polymer laminated steel in ironing, and offers several advantages over the previous material (Sellés [). This document shows a modelization for the ironing process (the most crucial step in can manufacturing) done by using a neural network.

Recent advances in LED technology have relegated the use of optical fibre for general lighting, but there are several applications where it can be used as scanners lighting systems, daylight, cultural heritage lighting, sensors, explosion risky spaces, etc. Nowadays the use of high intensity LED to inject light in optical fibre increases the possibility of conjugate fibre + LED for lighting applications. New optical fibres of plastic materials, high core diameter up to 12.6 mm transmit light with little attenuation in the visible spectrum but there is no an efficient and controlled way to extract the light during the fibre path. Side extracting fibres extracts all the light on 2 angle so is not well suited for controlled lighting. In this paper we present an extraction system for mono-filament optical fibre which provides efficient and controlled light distribution. These lighting parameters can be controlled with an algorithm that set the position, depth and shape of the optical extraction system. The extraction system works by total internal reflection in the core of the fibre with high efficiency and low cost. A 10 m length prototype is made with 45° sectional cuts in the fibre core as extraction system. The system is tested with a 1W white LED illuminator in one side.

In this research we compare the colorimetric behavior of several observers. For color centers recommended by CIE we have produced large sets of spectral distributions, which are metameric for the CIE 1931 standard observer. For each one of the color centers, we compare the clouds of chromaticity coordinates with the chromaticity thresholds. We define a parameter that provides a quantitative measure of the interobserver variability. This parameter is used to arrange the observers by their degree of likeness. A similar procedure has been used to compare two real observers. It is shown how there is no reciprocity between the colorimetric behavior of two real observers. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 262–269, 2001

This paper presents an optical microstructural model showing, the behavior of blown low-density polyethylene films as optical polymers (birefringence and anisotropy), at a structural level. The model is mainly based on a microstructural study involving the observation and analysis of increasingly smaller structures by transmission electron microscopy, POM, and X-ray diffraction, as a means of calculating the values of their orientation functions (the uniaxial approximation). These values enabled us to indicate graphically the most probable average position of the unit cell (the natural scale of our model) and hence of other crystalline structures. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1708–1720, 2000

AbstractA simple test is proposed to obtain a dimensional crystal evaluation by diffused-light analysis. The theoretical basis is shown in the form of an example taken from real structural determinations of blown polyethylene films obtained by transmission electron microscopy. The diffraction model is used for an equivalent grating derived from a planar and regular pavement.

We present spectroscopic ellipsometric measurements of TiO2thin films deposited on BK7 glass by electron beam reactive evaporation. The columnar morphology of the TiO2films has been observed with SEM. It has been modelled by means of three layers structures of porous TiO2of different thickness and filled in with various void/water concentrations. The agreement between measured ellipsometer parameters, tan Ψ and cos Δ, and the values derived from our model is almost complete. Finally, we have characterized the influence of relative humidity on TiO2thin films optical properties; variations in cos Δ and refractive index at different wavelengths are presented.

Some of the optical, mechanical, thermal, and chemical tests performed on a polycarbonate optical fiber (Optipol) developed by BAYER AG are described in this paper. Allthe tests were mainly done in order to evaluate the performances of this optical fiber, looking for its application as light transmitter in Local Area Networks (LANs) and sensors manufacture in the automobile industry. Some sensors using this fiber are also described in this paper: one speedometer, one tachometer, and one magnetometer. The last two sensors are Faraday effect sensors and have been developed with polycrystalline Cd1-xMnx, Te. This low-cost Faraday rotator has been specially manufactured by the authors to be used in industrial applications.

Refractometrical measurements of polyethylene films have been obtained using a modified Abbe's refractometer that includes polarized and monochromatic light. The ordinary and extraordinary refractive index values have been obtained considering an anisotropic uniaxic model. These values are analysed in relation to the previously known degree of crystallinity in the samples of this material. The specular reflectance is derived from the Fresnel formulae and an evaluation of diffused reflectance has been made. We find that the diffuse reflectance values increase with average roughness of the polyethylene films. This question is of particular interest for the surface characterization of these materials.

Natural light has been indispensable in architectural design for cost and quality reasons, as well as for natural environment conservation and psychological considerations. An application of array optics to natural lighting systems is reported in this paper. Theoretical study and a prototype of as optical array device(OAD) have been carried out. The OAD can be used as a static sunlight concentrator in a vertical mode, for oblique incidence and for the illumination of selected areas. The OAD is described in optical, configurational and lighting terms.

The effect of intracavity wavelength selectors on the position of tunable laser modes has been evaluated in the case of short light pulses propagating into the resonator. The narrow-peak approximation is analyzed for the calculus of extra phase introduced by an intracavity selector. A method also has been derived for the calculation of extra phase for a general-shape pulse f(y). In particular, the latter method is applied for a Gaussian-shape pulse.

We have measured the shift of the hfs components and broadening of the hfs components of the ground-state splitting for the D_1(8.943 Å) and D_2(8.521 Å) cesium lines in the presence of helium, neon, and argon, under pressures not greater than 150 torr and a temperature of about 295 K. The results for this same doublet are compared with the fine-structure data of other authors.

An experimental study is reported of the relationship between the degree of crystallinity of polyethylene tubular blown films obtained from x-ray diffraction and from density. The comparison shows that there are significant differences between the two techniques, and the values for percentage of crystallinity as determined by the density method are higher than those determined by the x-ray diffraction method. The main reason for these differences is the inclusion of the interfacial contribution to the measured density. The possible application of the analysis of the equation obtained for density crystallinity versus x-ray crystallinity in the evaluation of amorphous and crystalline domains in the interfacial region is discussed.

A new algorithm for phase unwrapping of phase maps with noise or logical inconsistencies is proposed. It is based on the use of an adaptive threshold and the second difference of the locally unwrapped phase as a selection criterion for the pixels to be processed.

We present an application of linear-programming techniques to generate metameric spectral radiant power distributions. Conditions concerning physical color properties, dominant wavelength, and excitation purity lead us to propose criteria that provide distributions associated with color stimuli with high-excitation purity values of any brightness. An unlimited number of metameric distributions can be obtained from the degrees of freedom introduced by the proposed criteria.

A new algorithm is proposed for solving the problems associated with discontinuity sources in phase maps. It is based on the stable-marriages algorithm and is implemented as a recursive procedure.With this technique, discontinuity sources of opposite sign are connected by a set of cut lines that fulfills a stability criterion and possesses the minimum cut length of the stable sets. The algorithm is fast and easy to implement and has proved efficient, as experimental results show.

The effects of the coating thickness on the physical performance of a Fabry–Perot interferometer (FP) are investigated. The FP is modeled as three media separated by two thin films and not merely by two interfaces. We show that the transmitted intensity obeys an Airy function, but not the reflected intensity because of the appearance of a complex factor accounting for the coupling between the reflected waves in the coatings. The Stokes relations are generalized for this model. We study the dependence of the phase lag of reflection in the coatings on the angle of incidence, which causes a shift in the position of the intensity maxima. We discuss as well the properties of the FP with an absorbing medium in the cavity, defining a merit function that optimizes the compromise between peak transmission and finesse.

A white-light speckle technique for measurement of flow velocities is described. The speckle patterns are formed by incoherent light at the image plane of the fluid illuminated section. The convection flow generated in a rectangular cell filled with silicone oil is studied with this technique. The flow velocities are obtained as the result of a point-by-point analysis. Alternatively, an overall picture of their spatial distribution is obtained by means of a whole-field filtering technique. The accuracy of the two methods of analysis is studied.

The intensity transmitted by a device made up of a F.P. etalon that contains another internal tunable F.P. has been studied. The theoretical predictions about the wavelengths of the intensity transmission maxima of the device are derived as functions of the optical path length of the internal F.P. An experimental check of the theoretical predictions is also presented.

For an optical bistable two-level system in a Fabry-Perot cavity we analyze the dependence of the transmitted field amplitude on three experimental parameters: the frequency of the incident radiation, the transition atomic frequency, and the length of the F.P. cavity. In each case the remaining parameters (including the input amplitude) are assumed to be fixed. Both absorptive and dispersive contributions are included, and in the mean-field approximation a cubic state equation should be solved. An explicit analytical expression for the transmitted intensity as a function of all physical parameters is obtained. Typical results are presented in graphical form. The main characteristic features of the optical hysteresis cycles are described and new possibilities for optical device design are examined. Use of the above explicit solution for stability analyses is briefly discussed.

We present a new approach for solving diffraction problems by radial gratings. The method, which uses a Cartesian coordinate reference system, allows us to perform the diffraction integral without prior knowledge of the explicit form of the grating-transmission function. As a result of simple physical arguments, it is possible to find analytical expressions for the diffracted field; and therefore the characteristics of the intensity distribution, such as its astigmatism, orientation, and beamwaist position, can be analyzed by means of the properties of the solution. By comparing the curvature radius of the two sections of the diffracted beam with that of the incident beam, we found that the behavior of the ±1 diffraction order can be well explained by means of two effective focal lengths, which depend only on the angular period and the radius of the grating, as well as on the wavelength of the illuminating source. We performed experimental measurements and obtained good agreement between the theoretical predictions and the experimental results.

In the present paper we discuss the time-delayed detection of the fluorescence signal in a level anticrossing experiment showing that, unlike what occurs in other methods, it does not lead, in general, to a signal profile narrowing as the delay time increases. However, we find conditions under which this technique provides the possibility of enhanced spectral resolution, as well as gives a direct measurement of the difference between the decay rates of the levels involved.

Automated fringe-pattern processing is important in a great number of industrial applications, such as optical data testing and quality control. One of the main problems that arises with these processes is the automated phase unwrapping of the phase map associated with the fringe pattern. Usually the phase map presents problems such as noise, and low-modulation areas. A new phase-unwrapping algorithm with high noise immunity is presented. The algorithm is easily implemented and can process arbitrary shapes. The main features of this algorithm are the use of a queue for the processing of arbitrary shapes and a selection criterion that determines which pixels are going to be processed.

The coupling between spatial and temporal parameters of ultrashort pulsed beams propagating through a dispersive system is treated by a 6×6 matrix formalism. A typical grating-pair system which is commonly used in pulsed beam compression is analysed in detail. Numerical examples show that the spatial-temporal coupling becomes severe under some conditions.

The coupling between spatial and temporal parameters of ultrashort pulsed beams propagating through a dispersive system is treated by a 6×6 matrix formalism. A typical grating-pair system that is commonly used in pulsed beam compression is analysed in detail. Numerical examples show that the spatial-temporal coupling becomes severe under some conditions.

An experimental verification of the dependence of the relaxation signal shape of an optically pumped vapor contained in an spherical cell on the radius of the cylindrical detection beam is presented.

An analysis of the anticrossing of several magnetic hyperfine sublevels of the same fine structure level is made. An expression for the resonance fluorescence signal is derived. Physical requirements for observation are discussed and lineshapes computed.

The influence of the distribution of light intensity in the pumping and detection beams on the shape of the relaxation signal of an optically pumped vapor contained in a spherical cell is studied. The following factors are considered: (1) exponential attenuation of pumping light intensity inside the cell; (2) Gaussian-shaped spatial distribution of intensity in the pumping light beam; and (3) cylindrical detection beam not covering, in general, the whole volume of the cell. The dependence of the relative amplitudes of the dominant diffusion modes on these factors is obtained. In particular, the contribution of the second most important mode to the relaxation signal is shown to vanish if the radius of the detection beam is 0.54 times the radius of the cell.

Trinitrofluorenone (TNF) and poly-n-vinylcarbazole (PVK) are commonly used in thermoplastic-photoconductor recording materials. The optical characterization of the layers of these films is of great interest in achieving maximum diffraction efficiency. Interference measurements of the optical thickness of absorbing media can be rapid and accurate. The real part of the refractive index is computed from the ellipsometric data in the range from 360 nm to 480 nm. It is extrapolated up to 780 nm and used with spectral transmittance and reflectance measurements to compute the imaginary part of the refractive index and the thickness of the sample of PVK:TNF. The sample is considered as a Fabry-Perot interferometer with surface defects. The defects arise from spatial inhomogeneities in the thickness. Non-linear regression analysis is applied to obtain the parameters of interest.

In this work, we describe the preparation of a novel photoconductive sol−gel material based on an organic/inorganic interpenetrating network (IPN). The composition of the sol−gel photoconductive material mimics the well-known polymeric one based on poly(N-vinylcarbazole) (PVK) as the charge-transporting matrix and 2,4,7-trinitro-9-fluorenone (TNF) as the sensitizer. The resulting photoconductive material (PVK/SiO2 IPN) shows a photosensitivity of 10^-11 cm/(Ω W) in range to that reported for some analogue polymeric compounds and the highest ever reported for hybrid sol−gel materials.

The distortion suffered by the amplitude and phase of a moiré signal when the illuminating beam is not a coherent and monochromatic plane wave has been measured by using different kinds of illuminating sources and a phase-sensitive intensity subtraction technique. A phenomenological model is proposed that explains these effects in terms of an irregular amplitude distribution and a phase evolution of the moiré signal with a grating gap. These effects are of great interest in all the measurement techniques related to the moiré effect, especially when compact light sources such as light-emitting diodes and incandescent lamps are used.

The replacement of single-crystal compounds by polycrystalline compounds in some magneto-optical devices is proposed. For this purpose a characterized polycrystalline, Cd_0.55Mn_0.45Te, has been manufactured. Its Verdet constant and cutoff wavelength are identical to those of single crystals of the same composition. Optical transmission is lower in polycrystals because they have larger light-scattering coefficients; hence they are not well suited for applications such as isolators but are adequate for magnetometers, modulators, and similar devices.

An automatic three-dimensional spectrogoniometer is presented. The wavelength of ligth and angles of incidence and observation are variable, making it capable of performing different optical characterizations in an integrated way.

Least-squares approximation can be used in image-based colorimetry once the set of sampling functions is selected. We discuss the accuracy obtained in earlier research, and we compare it with a better calculation method.

A method to enlarge the dynamic range of a CCD-based laser beam profiler is presented. The method is based on extended-image-range techniques. The algorithm that generates the extended-irradiance-range image is described in detail. An equivalent dynamic range and number of bits are defined and computed for the new profiling system. To test the method, experimental measurements of the principal widths of the output beam from a single-mode optical fiber have been made, as well as the Fraunhofer diffraction pattern of a 200-μm pinhole back-illuminated by a HeNe laser. © 2005 Society of Photo-Optical Instrumentation Engineers.