Search

Avaluar les pèrdues o guanys de potència (ɸ [W]) d’un edifici o habitació és important per determinar la necessitat de possibles reformes per millorar l’aïllament d’aquests; ja que com més grans siguin aquestes pèrdues o guanys de calor, es necessitaran més aparells de climatització que poden suposar més despeses econòmiques i un major impacte energètic. Aquest projecte es basa en la creació d’una pràctica docent per l’estudiantat de l’assignatura de Termotècnia, pertanyent al Q7 del Grau en Enginyeria en Tecnologies Industrials; on l’alumnat podrà aprendre els conceptes tèrmics principals relacionats amb l’edificació i a quantificar aquest bescanvi energètic amb l’exterior en una habitació de l’ETSEIB. Quan tots els fonaments teòrics que intervenen en aquestes pèrdues o guanys energètics s’han comprés; s’ha ideat el disseny d’un dispositiu amb sensors de temperatura i de flux de calor (q [W/m2]) per estudiar les superfícies de l’habitació on hi ha bescanvi energètic amb l’exterior; sempre tenint en compte la utilització del sensor de flux de calor HFP01. Un cop adquirit el material i elements implicats en el disseny inicial, s’han realitzat proves i estudis comparatius entre diverses opcions de sensors de temperatura, de microcontroladors per llegir mesures dels sensors i de diferents maneres de llegir les mesures que proporciona el sensor de flux de calor; arribant al muntatge experimental dels dispositius de mesura, tenint en compte aspectes com la facilitat de manipulació i la protecció dels components més sensibles. Amb el muntatge ja realitzat i després de les últimes comprovacions del seu correcte funcionament, s’han pres les mesures corresponents al Laboratori Docent de Termotècnia. Després de diversos càlculs i l’anàlisi d’aquestes mesures s’ha anat confeccionant el disseny i funcionament de la pràctica per l’estudiantat i les pautes d’avaluació pel professorat. Aquest projecte pot servir com a base per elaborar un guió per l’estudiantat que realitzarà la pràctica i per realitzar diferents proves de simulació de la pràctica; amb l’objectiu de corregir possibles errors de funcionament i de poder implementar aquesta pràctica docent a l’assignatura de Termotècnia Evaluar las pérdidas o ganancias de potencia (ɸ [W]) de un edificio o habitación es importante para determinar la necesidad de posibles reformas para el aislamiento de éstos; ya que cuánto más grandes son estas pérdidas o ganancias de calor, se necesitarán más aparatos de climatización que pueden suponer más gastos económicos y un mayor impacto energético. Este proyecto se basa en la creación de una práctica docente para el estudiantado de la asignatura de Termotecnia, perteneciente al Q7 del Grado en Ingeniería en Tecnologías Industriales; dónde el alumnado podrá aprender los conceptos térmicos principales relacionados con la edificación y a cuantificar este intercambio energético con el exterior en una habitación de la ETSEIB. Cuando todos los fundamentos teóricos que intervienen en estas pérdidas o ganancias energéticas se han comprendido; se ha ideado el diseño de un dispositivo con sensores de temperatura i de flujo de calor (q [W/m2]) para estudiar las superficies de la habitación donde hay este intercambio energético con el exterior, siempre teniendo en cuenta la utilización del sensor de flujo de calor HFP01. Una vez adquirido el material y los elementos implicados en el diseño inicial, se han realizado pruebas y estudios comparativos entre varias opciones de sensores de temperatura, de microcontroladores para leer las medidas de los sensores y de diferentes maneras de leer las medidas que proporciona el sensor de flujo de calor; llegando al montaje experimental de los dispositivos de medida, teniendo en cuenta aspectos como la facilidad de manipulación y la protección de los componentes más sensibles. Con el montaje realizado y después de las últimas comprobaciones de su correcto funcionamiento, se han tomado las medidas correspondientes en el Laboratorio Docente de Termotecnia. Después de diversos cálculos y el análisis de estas medidas se ha ido confeccionando el diseño y funcionamiento de la práctica para el estudiantado y las pautas de evaluación del profesorado. Este proyecto puede servir como base para elaborar un guion para el alumnado que realizará la práctica y para realizar pruebas de simulación de la práctica; con el objetivo de corregir posibles errores de funcionamiento y de poder implementar esta práctica docente en la asignatura de Termotecnia Evaluating the power (ɸ [W]) losses or gains of a building or room is important to determine the need for possible reforms for the insulation of these; since the greater these losses or heat gains are, the more air conditioning devices will be needed, which may involve more economic costs and a greater energy impact. This project is based on the creation of a teaching practice for Thermotechnics studens,a subject which belongs to Q7 of the Degree in Engineering in Industrial Technologies; where students can learn the main thermal concepts related to the building and to quantify this energy exchange with the outside in a ETSEIB room. When all the theoretical fundamentals involved in these energy losses or gains have been understood, the design of a device with temperature and heat flux (q [W/m2]) sensors has been devised to study the room surfaces where there is this energy exchange with the outside, always considering the use of the heat flux sensor HFP01. Once the material and the elements involved in the initial design were acquired, tests and comparative studies have been carried out between several options of temperature sensors, microcontrollers to read the sensor measurements and different ways to read the measurements provided by the heat flow sensor; arriving at the experimental assembly of the measuring devices, considering aspects such as ease of handling and protection of the most sensitive components. With the assembly done and after the last verifications of its correct operation, the corresponding measurements have been taken in the Thermotechnics Teaching Laboratory. After several calculations and the analysis of these measurements, the practice design and operation for the students and the evaluation guidelines for the teaching staff have been prepared. This project can serve as a basis for developing a script for the students who will perform the practice and to perform simulation tests of the practice; in order to correct possible operating errors and to be able to implement this teaching practice in the subject of Thermotechnics

In this paper a novel microgripper device is shown. It is based on a chevron type actuator, and a simple configuration of compliance beams. It is also considered a source of thermal energy, which in this case is 2 V, which generates a temperature of 92.7°C at the jaw’s tips. It is main advantage is given by the simplicity and the reduced number of beams, which composed the compliance arrangement of the microgrippers jaws. It is response competitive with other ones, more complex, found it in literature, both in displacement and force. The structural material is Silicon. The effect on the microgripper performance due to its thickness is also analyzed. Some applications of the microgripper are detected, for example, subjection of microwires and manipulation of micro objects with diameters smaller than 85$\mu$m, until 68 $\mu$m, and weights lower than 38.63 $\mu$g. All microgrippers simulations were done on Ansys software.

Using Poly-Silicon, the implementation of novel Displacement-amplifying Compliant Mechanisms (DaCM), in two geometries of accelerometers, allows for remarkable improvements in their operation frequency and displacement sensitivity, with different proportions. Similar DaCM´s geometries were previously implemented by us with Silicon. In all mentioned cases, the geometries of DaCM´s are adjusted in order to use them with Conventional Capacitive Accelerometer (CCA) and Capacitive Accelerometer with Extended Beams (CAEB), which operate in-plane mode, (y-axis). It should be noted that CAEB shows improvements (95.33%) in displacement sensitivity compared to ACC. Simulations results, carried out using Ansys Workbench software, validate the system’s performance designed with Poly-Silicon. Finally, a comparison with the similar systems, previously designed with Silicon, is also carried out.

In this paper, a modified U-shaped micro-actuator with a compliant mechanism is proposed. It was analyzed with a uniform and modified thin arm, as well as a similar variation in the corresponding flexure, in order to observe the impact of the compliant lumped mechanism. The use of these compliant mechanisms implies an increment in the deformation and a reduction in the equivalent stress of 25% and 52.25%, respectively. This characterization was developed using the Finite Element Method (FEM) in ANSYS Workbench. The design, analysis and simulation were developed with Polysilicon. In this study, the following performance parameters were also analyzed: force and temperature distribution. This device is supplied with voltage from 0 V up to 3 V, at room temperature. The modified U-shaped actuator was applied in both arms of a microgripper, and to evaluate its electrothermal performance, a static structural analysis has been carried out in Ansys Workbench. The microgripper has an increment in deformation of 22.33%, an equivalent stress reduction of 50%, and a decrease in operation frequency of 10.8%. The force between its jaws is of 367 &micro, N. This low level of force could be useful when sensitive particles are manipulated.

Microelectromechanical (MEM) Accelerometers measure the accelerations or vibrations experienced by objects due to inertial forces or mechanical excitations. To improve their proof mass displacement, several alternatives have been used, such as the design of different shapes of suspension beams. In this work, a new shape of beam is proposed based on alternated segments of different widths. To analyze its performance, one-quarter, middle and complete accelerometers were calculated and simulated, the results were compared with similar cases using conventional uniform-shaped beams. A notable improvement in the proof mass displacement was obtained in all cases, especially with the proposed symmetrical-shaped beam. Harmonic response and explicit dynamic analysis were also considered to discover performance when they are subjected to structural load. An improvement in amplitude displacement was also observed, as well as operation frequency reduction. From the explicit dynamic analysis, a faster performance of the accelerometer with uniform arms can be observed, however, it responds at a lower range of input velocities. A performance comparison of the proposed beam is presented considering the two reported accelerometers. Finally, from the variation in the width of the thinner segment of the symmetrical arms, it can be observed that it is possible to obtain an increment in the displacement of the proof mass of 39.57% and a decrement in natural frequency of 15.30%, with respect to the case of the uniform arm. Other advantages of the symmetric beam are the stress distribution, reducing its effect on the proof mass, as well as their low cross-axis sensitivity. Simulations were performed with ANSYS.

Accelerometers are widely used in several mechanisms of high sensitivity. They are employed for example in tilt-control in spacecraft, inertial navigation, oil exploration, seismic monitoring, etc. In order to improve the sensitivity of the measurements, implementation of Displacement-amplifying Compliant Mechanisms (DaCMs) in a capacitive accelerometer have been reported in the literature. In this paper, a system composed of two elements; capacitive accelerometer with extended beams (CAEB) and a DaCM geometry, of single and souble layer, are analysed. Three materials were considered, in the case, for the second layer. The DaCM implementation improves the operation frequency and displacement sensitivity, under different proportions, at the same time. Furthermore, three sweeps were performed: a range of thickness from 25 µm up to 30 µm (to determine the appropriate silicon mass value, using SOI technology), a range of second layer thickness (to choose the more appropriate material and its thickness) and a range of gravity values (to determine the maximum normal stress in the beams, which defines the superior value of the g operation range). The in-plane mode (y-axis) was considered in all analysed cases. This characterization was developed using the Finite Element Method. Structural and modal analysis responses were under study.

In this paper, the dynamic and electric analysis of a novel electrostatically actuated microdevice is presented. This device consist of an arrangement of four parallel microcantilevers, which is fed with 1 V. The analysis was carried out by Finite Element Method (FEM) in Ansys Workbench in order to obtain: current intensity, temperature distribution, Joule effect, structural deformation, natural frequency, and reaction force, which characterize the microgripper performance. The material used in the analysis was Silicon. A thermoelastic model, that describes the behavior mechanical of the device, is developed. The device had an initial gap of 28 µm and a final gap of ~ 4 µm, the force of subjection in grippers is 0.4 µN.

The displacement of the central shuttle of a Z-shape chevron actuator can be calculated using a developed approach from other authors. Who demonstrated that the actuators with this geometry offer a larger displacement compared with V-shape actuators. Z-shape offers a larger stiffness and output force for the case of only one arm. This paper is focused on the optimization of the Z-shaped beams of a chevron actuator of eight beams, which seeks to increase the previously described response. The structure is designed in parametric solid modeling 3D software Autodesk Inventor, and simulated by finite element method in Ansys 15.0. These simulations were implemented considering several modifications on the length of the Z-shaped beams in order to choose the most appropriate length. The electric potential applied in all cases was from 0.2 V up to 5 V. The Z-shape length of the arms for the case of the optimized Z-shape actuator increases the shuttle’s displacement in approximately 50% compared to V-shape actuator, and 38% compare to the original Z-shape. Analytical adjusted approach is extremely matched with the simulations results. Length of the Z-shape beam is the determinant factor of the displacement. The low stiffness of the optimized Z-shape actuator (89% lower than the original V-shape and 58% compared to Z-shape) can allow its use as load sensor.

The elastic behavior of a system can be determined by the stress analysis. This knowledge is useful in order to not exceed its limit of elasticity that means, to avoid permanent deformations, which can totally modify the performance of the system. In this paper, theoretical and simulated results of the normal stress generated in the folded beams of an accelerometer, under constant acceleration, are presented. The system under analysis has a suspended mass by means of four flat beams. The analysis was realized considering a cantilever, because this element is used as beam of support. A uniformly distributed load is present on the suspension beams. In simulations, 1g (9.81 m/s2) was applied to several accelerometers with different dimensions and geometries, with the purpose of observing that the normal stress should not exceed the elastic limit of silicon.

In this paper, the optimization of a chevron V-shape microactuator device to achieve higher actuation force and displacement is discussed. General information approach that includes the description of a physical model used in order to analyze the device behavior and the optimization of its design is considered. Shuttle and beams of a conventional electrothermal chevron V-shape microactuator device were modified. Pneumatic microactuators were implemented along the shuttle. The device was designed with silicon material. The device was characterized through a coupled electro-thermomechanical analysis using ANSYS-Workbench. Compared to the conventional chevron V-shape microactuator, the output work of the improved microactuator shows an increment of about 50% in displacement and 40% in actuation force, at the same maximum temperature source applied. A microgripper is developed are immediate application.

The micro-accelerometers are devices used to measure acceleration. They are implemented in applications such as tilt-control in spacecraft, inertial navigation, oil exploration, etc. These applications require high operating frequency and displacement sensitivity. But getting both high parameter values at the same time is difficult, because there are physical relationships, for each one, where the mass is involved. When the mass is reduced, the operating frequency is high, but the displacement sensitivity decreases and vice versa. The implementation of Displacement-amplifying Compliant Mechanism (DaCM) supports to this dependence decreases. In this paper the displacement sensitivity and operation frequency of a Conventional Capacitive Accelerometer are shown (CCA). A Capacitive Accelerometer with Extended Beams (CAEB) is also presented, which improves displacement sensitivity compared with CCA, and finally the implementation of DACM´s in the aforementioned devices was also carried out. All analyzed cases were developed considering the in-plane mode. The Matlab code used to calculate displacement sensitivity and operating frequency relationship is given in Appendix A.

In order to obtain antennas with adjustable bandwidth, arrays based on ring antenna are used, especially for the case when it is necessary to reduce it. The arrays are formed with an inner patch designed at the operation frequency of the system, and a gap coupled external ring, designed at other near lower frequency, which determines the bandwidth increment or decrement, respectively. Three basic ring geometries were considered: circular, rectangular and pentagonal, with RT/Duroid 5880 as a substrate. The feed point is located in the inner patch, in the external ring, a shorting pin is used. The changes achieved on the bandwidth are small, but considering the used principle it remains a useful approximation, that can be improved. There were obtained a maximum increasing of 53% and a maximum decreasing of 51.44%, compared to the bandwidth of the inner patch antenna, designed at 4.9 GHz and simulated as a single antenna.

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 elastic behaviour of a system can be determined by an analysis of stresses. The stress generated in the element loaded of an accelerometer is of interest here. In these devices, the suspension beams are the elements subjected to greater stresses, as they support the mass. The stress that they can support is limited by the elastic limit of the material. Based on this analysis, the operating conditions to prevent permanent deformations are determined. The analysis is focused on the acceleration applied to the accelerometer because this parameter increases considerably the stresses in the device. A relationship between normal stress and gravity applied is obtained. This equation is used in order to avoid exceeding the elastic limit, during the accelerometer operation. This fact determines the acceleration range supported by the device. In the literature, studies about the physics and modelling of accelerometers are performed. However, about the specific acceleration of operation which they are subjected, information about its determination is not provided. In this paper, the analysis is realized considering a Conventional Capacitive Accelerometer (CCA) and a Capacitive Accelerometer with Extended Beams (CAEB), particularly, on the normal stress. When a range of acceleration values are applied, normal stress occur which must not exceed the elastic limit of the material, as it was mentioned before. The Matlab code used to calculate this relationship is given in Appendix A.

The capacitive accelerometers based on microelectromechanical systems (MEMS), are widely used in the automotive industry, in seismic detection, and in military applications. The sensitivity is one of their main characteristics, which widely benefit their use in front of small acceleration changes. In this work, the elements considered in the analyses of these systems are mass and suspension beams, which constitute a mass-spring system. The mathematical modelling establish its mechanical response. Based on the equations of sensitivity and frequency of displacement response sets out the criteria to determine the geometry of the mass and the length of suspension beams are obtained in order to improve the sensitivity response. The importance of the stiffness constant is also considered as part of the design. Inthis case, the changes in the mass produces irregular geometries that, at the same time, allows to increase the beam’s length. The improvement in the sensitivity value permits the actuation at lower levels of acceleration. In addition, the simulation of the vibration mode, corresponding to the in-plane displacement, is carried out with the purpose of determining the appropriate frequency for the system operation. Material used for the actuator implementation is silicon. ANSYS is the software used to carry out simulations and characterization of the analyzed systems.

Our understanding of the immune responses to pancreatic tumors is very limited. Analysis of the preexisting immune responses against a panel of tumor-associated antigens could help generate new immune-based therapies and diagnostic tools. Furthermore, the majority of the few studied tumor-associated antigens found in pancreatic cancer are not clinically relevant or important for cancer cell survival. Animal and clinical immunotherapeutic studies have demonstrated that there is immune selection and immune escape against most of these antigens. Overactivation of the epidermal growth factor pathway, apoptosis-related proteins and death resistance of cancer stem cells and tumor stroma have been observed in human pancreatic cancer and often are associated to overexpression or deregulation of several proteins including EGFR, Her-2, Bcl-2, survivin, Wnt-1, and Sox2. EGFR, Her-2, Bcl-2, survivin, Wnt-1, and Sox2 are implicated in tumor aggressiveness, progression, resistance, and metastasis. Overexpression of these proteins in the tumor cells and tumor stroma of advanced pancreatic cancer, and the lack of relevant mutations make them reliable targets for clinical immunotherapy trials. We designed long peptides representing immunogenic T helper and CTL epitopes for all these six proteins. The immune response was studied in pancreatic cancer (n=15), pancreatitis (n=17) and matched controls. PBMCs were analyzed to determine Th1 and Th2 immune response by production of IFN-γ and IL-10 respectively using an ELISPOT assay. Sera and ascites fluid were used for the study of the humoral immune response by ELISA using human anti-IgG and human anti-IgA. We detected significant preexisting humoral and cellular immune responses against these peptides in patients suffering from advanced pancreatic cancer. In this study, we demonstrated that this panel of proteins could be targets for humoral and cellular immune recognition in pancreatic cancer patients whereas no detectable responses were found in healthy patients. Our results suggest that a Th2 immune response is present more often in this cohort and that it could be associated with a poor prognosis measured by overall survival. In conclusion, Th2 and ascites IgA immune responses against proteins important for tumor survival that are overexpressed in cancer cells and tumor stroma were common in our cohort of pancreatic cancer patients. Some of these proteins could serve as broad-spectrum tumor antigens to target in peptide vaccine immunotherapy trials to achieve better clinically relevant responses in pancreatic cancer patients. Citation Format: Jose V. Torres, Gardner B. Murray, Ramon Cabello, Eduardo Flores, Alejandro Camacho, Pedro A. Lucero, Anton Ostashko, Roger Dela Cruz, Jr., Fernando Durazo, Xia Li, Lizette Rodriguez, Erik Ramos, Juan Pablo Marquez-Manriquez. Preexisting immune responses against EGFR, Her-2, Bcl-2, survivin, Wnt-1, and Sox2 in pancreatic cancer patients. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Progress and Challenges; Jun 18-21, 2012; Lake Tahoe, NV. Philadelphia (PA): AACR; Cancer Res 2012;72(12 Suppl):Abstract nr A54.

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.

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".