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Due to the diversity and multiple energy domains involved, Micro-Electromechanical Systems MEMS devices are vulnerable to several mechanical failures such as fatigue. They been widely used in military applications, radio frequency systems, pressure sensors, automotive industry, among several others. Most MEMS devices contain moving parts that are subjected to cyclic loading, which degrade the device´s efficiency. Due to the high importance of MEMS in various applications, it is necessary to know their lifetime to prevent any damage or process discontinuity to which the system is subject. There have been several investigations in particular on the fatigue analysis in presence of cracks, however in terms of lifetime under cycling load, information is not abundant. The fatigue analysis can be performed for characterizing the ability of materials to support many cycles. Some parts of systems are exposed to strong stress level experiences during its usable lifetime, so the analysis must be focused on them. In this paper, a simulated fatigue analysis of classic, Z-shape and optimized chevron with Z shape arms is shown. Simulations are made using Ansys 15.0, to obtain the arms lifetime of the system because they are subjected to greater stresses in the presence of cyclic loading.

For illumination sources designers is important to know the illumination distribution of their products. They can use several viewers of IES files (standard file format determined by Illuminating Engineering Society). This files are necessary not only know the distribution of illumination, but also to plain the construction of buildings by means of specialized softwares, such as Autodesk Revit. In this paper, a complete portable system for luminaries’ characterization is given. The components of the systems are: Irradiance profile meter, which can generate photometry of luminaries of small sizes which covers indoor illumination requirements and luminaries for general areas. One of the meter´s attributes is given by the color sensor implemented, which allows knowing the color temperature of luminary under analysis. The Graphic Unit Interface (GUI) has several characteristics: It can control the meter, acquires the data obtained by the sensor and graphs them in 2D under Cartesian and polar formats or 3D, in Cartesian format. The graph can be exported to png, jpg, or bmp formats, if necessary. These remarkable characteristics differentiate this GUI. This proposal can be considered as a viable option for enterprises of illumination design and manufacturing, due to the relatively low investment level and considering the complete illumination characterization provided.

A complete adjustable and automated system has been developed on the base of three blocks: the first one is the mechanical and adjustable structure, which is composed by a mobile base and a rectangular arc, where the photodetector is located. The structure describes semi-spherical trajectories by means of two servomotors. Its lightweight and robustness constitutes two advantages which make it portable. The second stage corresponds to the automation of the structure movements. For controlling the motors and data acquisition, a microcontroller is employed that in turns helps keeping the cost of the overall system low. One of the servomotors is located on the lateral axis of the device; that displaces the sensor along a semi-circular trajectory of 160°, almost half meridians; the other one is located at the base of the illumination source, which enables it to realize an almost complete rotation around its axis. Finally, the last stage is formed by the graphical interface. The communication protocol between the data acquisition stage and the computer is USART. The graphical user interface (GUI) is developed using Visual C#. In the same window the data acquisition deployment and the data graph generator are given; the graphs can be shown in a polar or Cartesian formats showing more than one curve, if necessary, avoiding the use of additional software. The GUI keeps the low cost of the device, obtaining a comprehensive solution to generate the irradiance patterns of light sources.

The NiTiNOL diaphragm, under two geometries, were simulated on a Silicon wafer and controlled by an external heat source. As the substrate bottom wall heats and conducts heat, the thermal expansion raises the thin layer which can be used as an actuator. The case of heat source applied on the top walls was also considered. The simulations were realized by means of the mechanical and thermal properties of materials. A comparison among the performance of the diaphragm based on the geometries with a plane layer, a layer with a primary boss, and finally with primary and secondary bosses is presented. Each process was simulated in COMSOL Multiphysics. The distribution of deformation using bosses is similar to the analyzed cases using pressure instead of heat. The maximum obtained displacement for NiTiNOL is of approximately 2.5 micrometers at 343°K, at the same conditions, Silicon case reaches 0.9 μm. The diaphragm behavior is also compared with the cases of Silicon and Cu-Al-Ni. Our interest in the development of MEM actuators only controlled by external heat sources is due to several reasons. At first, because these clean energy sources sometimes reaches high density values, but they have not been well-spent. The most of MEMS thermal actuators need a current flow to heat the MEM device, by means of the Joule effect, and produce the corresponding thermal expansion. In this paper, the displacement depends on the external source, in accordance with the mechanical and electrical properties of the used materials.

The semi-spherical meter uses a photo-detector mounted on a mobile rectangular arc, which by means of two stepper motors describes the semi-spherical trajectories required. For controlling motors and data acquisition, a Peripheral Interface Controller (PIC) is employed, which helps keeping the low cost of the overall system. One of the stepper motors is located on the lateral axis of the device; that displaces the sensor along a semi-circular trajectory of 170°, almost complete meridians. Another motor located at the base of the device enables 360° rotation of the illumination source under test. The precision is increased by the using of two angle sensors located on the opposite lateral axis and on the mobile base of the illumination source. Additionally, before the data obtained from the photo-detector arrive to the PIC, a stage of signal conditioning is used. This step allows us to increase not only the precision, but also the versatility of the meter to analyze illumination sources of different sizes and fluxes. The communication protocol between the data acquisition stage and the computer is USART. A graphical user interface (GUI) is employed on the base of the hyperterminal. The number of measurement points is determined by programming the two motors. The mechanical structure provides enough rigidity for supporting the accuracy required by the data acquisition circuitry based on a PIC. Measurement of illumination sources of different sizes is possible by using adjustable lengths of the mobile base and the ring.

In this semi-spherical meter, a single detector is used to realize all measurements, which is located on the extreme of a rectangular ring (assumed as joined two mobile branches in order to compensate the weights), describing half-meridians from 0° up to 170°. The illumination source under test is located at the center of the mobile support, which can rotate 360° horizontally. The two combined movements allow us to obtain a semi-spherical geometry. The number of measurement points is determined by the two step-motors located under the mobile support of the luminary and on one of the two fixed arms, which support the mobile rectangular ring, respectively. The mechanical arrangement has the enough rigidity to support the precision required for the acquisition stage, based on a dsPIC. The main advantages of this arrange are: Its low costs (using recyclable materials only such as "electronic waste"), a reliable detection based on a single photo-detector, with an integrated amplification stage, and the mechanical design. The received power by the detector is useful to obtain the irradiance profile of the lighting sources under test. The semi-spherical geometry of the meter makes it useful for the analysis of directive and non directive sources, in accordance with the angle described by the mobile ring. In this work, special attention is given to LED lamps due to its impact in several sceneries of the daily life. A comparison between the irradiance patterns of two LED lamps is also given.

Antenna characteristics are chosen according to the features determined by the systems where they will be used. While some systems require a very narrow bandwidth, others may operate with a much wider bandwidth. Some techniques used for increasing the bandwidth of a given antenna have considered mechanical adjustment of the air layer thickness, with the consequent change on the effective permittivity and performance. Some other systems consider a suitable choice of feeding techniques and impedance matching network. However, approaches for reducing the bandwidth have not received the same level of attention. Narrow bandwidth antennas are of particular interest in security and surveillance systems. In this work we present a technique, based on the design of a pentagonal antenna array, which allows for adjusting the bandwidth in either direction. The array is formed by an inner patch designed at the desired operating frequency of the system and a gap coupled external ring centered at a different frequency (lower or very near the operating frequency), which determines the potential bandwidth increment or decrement. The feed point is located on the inner patch. As a proof-of-concept, this work offers a tuning range that goes from -40% of the center frequency up to +50% of the center operating frequency of the patch antenna. The single patch antenna of this work was designed and simulated at an operating frequency of 4.9 GHz on RT/Duroid 5880.

The meter device presented in this work consists of a photo-detector mounted on the mechanism of a mobile rectangular arc. One stepper motor located on the lateral axis of the device displaces the sensor along a semi-circular trajectory of 170°, almost half meridians. Another motor located at the base of the device enables 360° rotation of the illumination source under test. This arrangement effectively produces a semi-spherical volume for the sensor to move within. The number of measurement points is determined by programming the two stepper motors. Also, the use of a single photo-sensor ensures uniformity in the measurements. The mechanical structure provides enough rigidity for supporting the accuracy required by the data acquisition circuitry based on a DSPIC. Measurement of illumination sources of different sizes is possible by using adjustable lengths of the mobile base and the ring for a maximum lamp length of 0.16 m. Because this work is partially supported by a private entity interested in the characterization of its products, especial attention has been given to the luminaries based on LED technology with divergent beams. The received power by the detector is useful to obtain the irradiance profile of the lighting source under test. The meter device presented herein is a low-cost prototype designed and fabricated using recyclable materials only such as "electronic waste".

Applications of Multimode Interference (MMI) effects in optical devices have been increased today due their excellent properties and easy fabrication. Incorporation of these effects in optical fiber has been achieved through a single-mode - multimode - single-mode (SMS) fiber structure showing high sensitivity to bending-loss phenomenon. The latter has been efficiently implemented in pressure sensing application such as is presented in this work. Basically, the SMS structure is embedded in a pressure-sensitive membrane to convert pressure in a mechanical displacement resulting in an attenuation of the transmitted intensity proportionally to the applied pressure. Under this configuration, an all-fiber pressure sensor with high sensitivity and repeatability is obtained into a pressure range from -13 psi to +13 psi. The max pressure range can be varied to 140 psi with our configuration when the membrane thickness is changed. Important features of the proposed all-fiber MMI pressure sensor are its easy-fabrication and low-cost since an inexpensive instrumentation is required.

We discuss a structured 3D Dielectric Photonic Crystal with both a metallic core and a metallic shell. We discuss the role of each one, the stack, the core as well as the cavity formed between the core and the shell. The low frequency metallic core features becomes much more significant as it gets smaller and get diluted by the cavity.

In this work, the development of a spherical irradiance meter is presented. The illumination intensity measurements are made by means of a photo-detector assembled on a mechanical setup. The received power by the detector is useful to obtain the irradiance profile of the lighting source under test, considering a discrete set of points. This detector is located at the edge of the mobile arm of the mechanical system, which makes a sweep considering two movements directed by the azimuthal and zenithal angles, generating analogous paths to the terrestrial meridians, covering a semi-sphere of 27 cm of radius. The concentric trajectories consider lighting source under test at their center. The radiation pattern of each lighting source is generated using the irradiance data and the detector positions. The mechanical structure has a horizontal mobile base, which allows a 360° rotation. At the same time, one of its extremes serves as base of the mobile arm, which allows the vertical movements and provides the sensor support. The movements are controlled by step motors determining the data collection points. They also define the horizontal and vertical resolution. The obtained data is visualized by means of a display.

In this work, we present the basic considerations of a solar follower, realized with a control module based on a Dspic 30F40011. The Dspic was programmed considering the basic equations to track the apparent sun position. The Dspic programming was realized considering three fundamental blocks: Real time clock, the movement determined by the hour angle, and the movement determined by the declination angle (based on a CD motor). The mechanical design was realized considering a parabolic antenna used as concentrator, with a diameter of 60 cm, a depth of 6 cm, weight of approximately 1.5 kg, made of glass fiber. The control module is easy to use due to the LCD implementation, which indicates all necessaries entries to the correct operation of each block. The LCD is also used to display the date, hour, and the temperature obtained by the sensor temperature located at the antenna focus. As a proof of the correct system calibration and operation, the shadow of the sensor temperature circuit was located at the antenna center, during all realized probes. Due to the antenna characteristics, which were made by hands, the amount of thermal energy is relatively small but for example, enough to heating water. The obtained temperature can be increased by replace the antenna, without to redesign the mechanical and electronic systems because they can be used for antennas weight until 15 kg.

This paper describes the design and experimental characterization of two optimized thermal actuators devised to operate by means of scavenging heat from the environment. Different from the traditional MEMS thermal actuator that relies on electric current to generate heat by Joule effect, the devices herein presented have been optimized to absorb external heat and convert it into mechanical displacement and force. The behavior of vertical and horizontal microactuators fabricated in a standard surface micro-machining process (PolyMUMPs) demonstrates the viability of exploiting heat from the surrounding medium to realize batteryless microsystems. Analytical and finite element models are provided in support of the design. Results show that fairly large and useful displacements can be achieved at commonly available operating temperatures.

Annular Photonic structures, which occur on bulk and fibers, are Bragg structures that share both Bragg resonances and waveguiding. They are related to Photonic crystals because of their large enough refraction difference indexes (n 2 - n 1 ) that makes unavoidable to consider in full the reflected wave, well beyond the approximations required for analytical gap solitons. Effectively, their confining capabilities are or primary importance, however, the potential of those structures are substantial and deserves to be further explored. Waveguiding occurs where the structure is homogenous, and may be handled on well known methods. Nonlinear propagation has been observed on solid core Bragg fibers and the soliton distribution on a nonlinear circular and annular region have been described [1]. Linear Photonic annular structures, such as resonators, have been studied by A. Yariv [2] as well as on omniguide fibers. The propagation along the direction where the material is inhomogenous, and that correspond to the beam profile, is a complex task and it is the objective of this paper.

The study of nonlinear photonics crystals is quite complex and cumbersome, because of their inherent architectural complexity and, in addition, because of the nonlinearity that couples propagating and counterpropagating waves. However, they are quite attractive because of their potential capabilities, and that has lead to use different approximated methods. In a one dimensional stack, it has been successfully demonstrated that they show switching, bistability and chirping as nonlinear characteristics. Band gap solitons are a well established feature of the coupled wave equations. We have extended a method that have previously shown its success for a stack with a Kerr nonlinearity, to a much more complex structure such as an omniguide fiber, as part of our suggestion that such method could be applied to numerical or analytical methods as long as the linear solution were available. Such a restriction, hinder our ability of getting analytical solution beyond their enabling approximations, however, it is completely adequate for the purpose of to develop devices. A comparative numerical analysis of a one dimensional photonic crystal and an omniguide fiber, made of a dielectric and stratified linear and nonlinear media, has been carried out. They were considered as multilayer arrangements with a finite numbers of periods: linear-linear, nonlinear-linear and nonlinear- nonlinear in order to study and isolate those features. Finally, a comparison of multilayer systems with variations in the diffraction indexes profiles is presented.

E. Gonza1ezRamirezl*, J D. Cluckie1, M. Tecpoyotl-Torres2, M. A. Rico-Ramirez', G. Cerda-Villafafla1 J Escobedo-Alatorre2 and J. Sanchez-Mondragon31Water and Environmental Management Research Centre (WEMRC), Department of CivilEngineering, University ofBristol, Lunsford House, Cantocks Close, Bristol BS8 1UP;2Research Center ofApplied Sciences and Engineering (CIICAp), Autonomous University ofMorelos State (UAEM); Av. Universidad No. 1001, C. P. 62210,Cuemavaca, Mor., Mexico;3National Institute for Astrophysics, Optics and Electronics (INAOE),P.O. 51 & 216, Z.P. 72000, Puebla, Mexico.ABSTRACT

We present in this paper a data fitting method that analyzes a spherical shell that uses the near orthogonality of the Spherical Harmonics Y lm (4,)) within a discrete data collected on a spherical shell to obtain the best rms fit. This is obtained through the generation of an orthogonal basis from the spherical harmonics Y lm (4,)) on a discrete and often irregular data set on a spherical shell. 1. JUSTIFICATION The problem of data fitting on a spherical shell is not privative of optics, since it can find in many other fields such as microwaves sensing, radiative problems, biology, geology, medicine and many others. The ideal conditions of an analytical description have been careful included in the detailed experimental analysis, where such idealizations are taken care off by being an essential part of the data fitting. Optics has developed quite efficient interferometric techniques on a circular pupil (see Figure 1a) based on Zernike Polynomials and in particular by a discrete domain defined by the data set, which do not need to be regular distributed, and where those Zernike alike polynomials have become their best fit for both the data and the functional description. These features, are exceptionally convenient in other domains, where near continuous arrays of detectors such as CCD´s arrays are not easily available or do not exists. Data fitting on a spherical shell in many radiative problems are typical problems with these characteristics. However, the capability to deal with wavefronts on spherical problems is much more cumbersome experimentally, which makes quite attractive carry out similar procedures based on point like detectors. Different efforts have been developed to treat those problems such as: x A Double Fourier series has been discussed (1974), but its inadequacies has been already pointed out