Academic literature on the topic 'Diaphragm – Mechanical properties'
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Journal articles on the topic "Diaphragm – Mechanical properties"
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Farkas, G. A., L. E. Gosselin, W. Z. Zhan, E. H. Schlenker, and G. C. Sieck. "Histochemical and mechanical properties of diaphragm muscle in morbidly obese Zucker rats." Journal of Applied Physiology 77, no. 5 (November 1, 1994): 2250–59. http://dx.doi.org/10.1152/jappl.1994.77.5.2250.
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The purpose of the present study was to evaluate the effects of chronic mass loading produced by obesity on the structural and functional characteristics of the diaphragm in lean and obese Zucker rats. The trapezius muscle served as an internal control. The studies were carried out on 17 lean (303 +/- 24 g) and 16 obese (698 +/- 79 g) Zucker rats. We observed that the diaphragms from obese animals were restructured such that the overall contribution of type I and IIa fibers was significantly increased. As a consequence of this remodeling, overall diaphragm thickness was selectively greater in obese animals. In small isolated diaphragm bundles studied in vitro, we also detected a reduction in specific force in obese animals that was not detected in the trapezius muscle. In vitro fatigue resistance, assessed by repeated stimulation, was similar in muscles of lean and obese animals. Diaphragm fiber oxidative capacity (succinate dehydrogenase activity) was also comparable in lean and obese animals. We conclude that in obesity the diaphragm undergoes modest remodeling that may be beneficial in enhancing force generation.
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Yu, Bo Lin, and Fa Hong Yu. "The Study on Diaphragm's Mechanical Properties of Hot-Film Air Flow Sensor." Advanced Materials Research 774-776 (September 2013): 1577–81. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.1577.
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In this paper, the diaphragms Mechanical property of Hot-film air flow sensor is studied on the base of proposition of double-sided convection heat air flow sensor. This diaphragm consists of barrier layer, support layer and passivation layer. For Hot-film air flow sensor, the Diaphragms Mechanical property is mainly up to the support layer, and the support layer is composed of Si3N4. In this research, four types of air flow sensors with different thickness of the support layer is prepared and tested at different air flow velocity. On the same time, the stress analysis of the sensor diaphragm is simulated at the flow rate of 5m/s by the finite element software. A conclusion can be drawn that the thickness of support layer can not be less than 1000nm, when the air flow velocity is more than 5m/s.
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Sassoon, Catherine S. H., Vincent J. Caiozzo, Albana Manka, and Gary C. Sieck. "Altered diaphragm contractile properties with controlled mechanical ventilation." Journal of Applied Physiology 92, no. 6 (June 1, 2002): 2585–95. http://dx.doi.org/10.1152/japplphysiol.01213.2001.
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This study shows that, over time, diaphragm inactivity with controlled mechanical ventilation (CMV) decreases diaphragm force and produces myofibril damage contributing to the reduced force. We measured in vivo and in vitro diaphragm contractile and morphological properties in 30 sedated rabbits grouped ( n = 6) as follows: 1 or 3 days of CMV, 1 or 3 days of 0 cmH2O continuous positive airway pressure, and control. The CMV rate was set sufficient to suppress diaphragm electrical activity. Compared with the control group, phrenic-stimulated maximum transdiaphragmatic pressure did not decrease with continuous positive airway pressure but decreased to 63% after 1 day of CMV and to 49% after 3 days of CMV. The in vitro tetanic force decreased to 86% after 1 day of CMV and to 44% after 3 days of CMV. After 3 days of CMV, significant myofibril damage occurred in the diaphragm but not in the soleus. The decrease in tetanic force correlated with the volume density of abnormal myofibrils. We conclude that CMV had a detrimental effect on diaphragm contractile properties.
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Guerrini, Gabriele, Christian Salvatori, Ilaria Senaldi, and Andrea Penna. "Experimental and Numerical Assessment of Seismic Retrofit Solutions for Stone Masonry Buildings." Geosciences 11, no. 6 (May 27, 2021): 230. http://dx.doi.org/10.3390/geosciences11060230.
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This paper presents an experimental and numerical study on different retrofit solutions for stone masonry buildings with timber diaphragms in earthquake-prone regions, aiming at enhancing wall-to-diaphragm connections, diaphragms’ stiffness, and masonry properties. The experimental results of incremental dynamic shake-table tests on three full-scale two-story buildings, complemented by material and component characterization tests, are initially summarized. The first building specimen was unstrengthened. The second one was retrofitted at the floor and roof levels with improved wall-to-diaphragm connections and a moderate increase in diaphragm stiffness. Connections were also improved in the third specimen together with a significant enhancement of diaphragm stiffness. The calibration of two numerical models, versus the experimental response of the retrofitted building specimens, is then presented. The models were further modified and reanalyzed to assess the effects of masonry mechanical upgrades, which could be achieved in practice through deep joint repointing or various types of jacketing. These solutions were simulated by applying correction coefficients to the masonry mechanical properties, as suggested by the Italian building code. The effectiveness of the experimentally implemented and numerically simulated interventions are discussed in terms of strength enhancement and failure modes.
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Boriek, Aladin M., Y. Capetanaki, Willy Hwang, Todd Officer, Muffasir Badshah, Joe Rodarte, and James G. Tidball. "Desmin integrates the three-dimensional mechanical properties of muscles." American Journal of Physiology-Cell Physiology 280, no. 1 (January 1, 2001): C46—C52. http://dx.doi.org/10.1152/ajpcell.2001.280.1.c46.
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Striated muscle is a linear motor whose properties have been defined in terms of uniaxial structures. The question addressed here is what contribution is made to the properties of this motor by extramyofilament cytoskeletal structures that are not aligned in parallel with the myofilaments. This question arose from observations that transverse loads increase muscle force production in diaphragm but not in the hindlimb muscle, thereby indicating the presence of structures that couple longitudinal and transverse properties of diaphragmatic muscle. Furthermore, we find that the diaphragms of null mutants for the cytoskeletal protein desmin show 1) significant reductions in coupling between the longitudinal and transverse properties, indicating for the first time a role for a specific protein in integrating the three-dimensional mechanical properties of muscle, 2) significant reductions in the stiffness and viscoelasticity of muscle, and 3) significant increases in tetanic force production. Thus desmin serves a complex mechanical function in diaphragm muscle by contributing both to passive stiffness and viscoelasticity and to modulation of active force production in a three-dimensional structural network. Our finding changes the paradigm of force transmission among cells by placing our understanding of the function of the cytoskeleton in the context of the structural and mechanical complexity of muscles.
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Mifuji, Shinichiro, Koji Adachi, Tatsunori Tsukioka, and Satomitsu Imai. "Thermal Driving Method and Displacement Properties of a Thin-Film Polyimide Diaphragm for a MEMS Actuator." Key Engineering Materials 523-524 (November 2012): 563–68. http://dx.doi.org/10.4028/www.scientific.net/kem.523-524.563.
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A thin-film polyimide diaphragm for a MEMS actuator was fabricated and its process and mechanical characteristics were investigated. Owing to its low elastic modulus and the thin-film process, a thin-film polyimide diaphragm has a merit in terms of producing a large displacement. Given that merit, spin coating was used for forming a thin film of polyamide, and deep-RIE (Bosch process) was used for fabricating the diaphragm section of the actuator. Thin-film polyimide diaphragms with micrometer-order thickness were fabricated. To drive the diaphragm as an actuator, the following two methods were applied: heat expansion by applying an electric current and volume expansion of a gas-liquid phase-change material confined in a cavity between polyimide diaphragms. As for the former method, an aluminum thin film is deposited on the diaphragm. As for the latter, paraffin (vaporized by heating) is used as the phase-change material. Displacement characteristics for each method were revealed by the experiments. In the case of both methods, displacements of tens of micrometers were outputted. Experiments of driving actuator confirmed that the proposed systems work as actuators. The actuators developed in this research are applicable to micro-pumps for medical and other uses.
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Lopez, M. A., U. Mayer, W. Hwang, T. Taylor, M. A. Hashmi, S. R. Jannapureddy, and Aladin M. Boriek. "Force transmission, compliance, and viscoelasticity are altered in the α7-integrin-null mouse diaphragm." American Journal of Physiology-Cell Physiology 288, no. 2 (February 2005): C282—C289. http://dx.doi.org/10.1152/ajpcell.00362.2003.
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α7β1 integrin is a transmembrane structural and receptor protein of skeletal muscles, and the absence of α7-integrin causes muscular dystrophy. We hypothesized that the absence of α7-integrin alters compliance and viscoelasticity and disrupts the mechanical coupling between passive transverse and axial contractile elements in the diaphragm. In vivo the diaphragm is loaded with pressure, and therefore axial and transverse length-tension relationships are important in assessing its function. We determined diaphragm passive length-tension relationships and the viscoelastic properties of its muscle in 1-month-old α7-integrin-null mice and age-matched controls. Furthermore, we measured the isometric contractile properties of the diaphragm from mutant and normal mice in the absence and presence of passive force applied in the transverse direction to fibers in 1-month-old and 5-month-old mutant mice. We found that compared with controls, the diaphragm direction of α7-integrin-null mutants showed 1) a significant decrease in muscle extensibility in 1-year-old mice, whereas muscle extensibility increased in the 1-month-old mice; 2) altered muscle viscoelasticity in the transverse direction of the muscle fibers of 1-month-old mice; 3) a significant increase in force-generating capacity in the diaphragms of 1-month-old mice, whereas in 5-month-old mice muscle contractility was depressed; and 4) significant reductions in mechanical coupling between longitudinal and transverse properties of the muscle fibers of 1-month-old mice. These findings suggest that α7-integrin serves an important mechanical function in the diaphragm by contributing to passive compliance, viscoelasticity, and modulation of its muscle contractile properties.
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Pardo, Patricia S., Michael A. Lopez, and Aladin M. Boriek. "FOXO transcription factors are mechanosensitive and their regulation is altered with aging in the respiratory pump." American Journal of Physiology-Cell Physiology 294, no. 4 (April 2008): C1056—C1066. http://dx.doi.org/10.1152/ajpcell.00270.2007.
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The mechanical regulation of the forkhead box O (FOXO) subclass of transcription factors in the respiratory pump and its implication in aging are completely unknown. We investigated the effects of diaphragm stretch on three FOXO isoforms, Foxo1, Foxo3a, and Foxo4, in normal mice at different ages. We tested the hypotheses that 1) FOXO activities are regulated in response to diaphragm stretch and 2) mechanical properties of aging diaphragm are altered, leading to altered regulation of FOXO with aging. Our results showed that stretch downregulated FOXO DNA-binding activity by a mechanism that required Akt and IKK activation in young mice but that these pathways lost their mechanosensitivity with age. This aberrant regulation of FOXO with aging was associated with altered viscoelasticity, compliance, and extensibility of the aged diaphragm. Curiously, the dramatic decrease of the nuclear content of Foxo1 and Foxo3a, the two isoforms associated with muscle atrophy, with aging correlated with higher basal activation of Akt and IKK signaling in diaphragms of old mice. In contrast, the stability of Foxo4 in the nucleus became dependent on JNK, which is strongly activated in aged diaphragm. This finding suggests that Foxo4 was responsible for the FOXO-dependent transcriptional activity in aging diaphragm. Our data support the hypothesis that aging alters the mechanical properties of the respiratory pump, leading to altered mechanical regulation of the stretch-induced signaling pathways controlling FOXO activities. Our study supports a mechanosensitive signaling mechanism that is responsible for regulation of the FOXO transcription factors by aging.
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Lopez, Michael A., Patricia S. Pardo, Gregory A. Cox, and Aladin M. Boriek. "Early mechanical dysfunction of the diaphragm in the muscular dystrophy with myositis (Ttnmdm) model." American Journal of Physiology-Cell Physiology 295, no. 5 (November 2008): C1092—C1102. http://dx.doi.org/10.1152/ajpcell.16.2008.
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A complex rearrangement mutation in the mouse titin gene leads to an in-frame 83-amino acid deletion in the N2A region of titin. Autosomal recessive inheritance of the titin muscular dystrophy with myositis ( Ttn mdm/mdm) mutation leads to a severe early-onset muscular dystrophy and premature death. We hypothesized that the N2A deletion would negatively impact the force-generating capacity and passive mechanical properties of the mdm diaphragm. We measured in vitro active isometric contractile and passive length-tension properties to assess muscle function at 2 and 6 wk of age. Micro-CT, myosin heavy chain Western blotting, and histology were used to assess diaphragm structure. Marked chest wall distortions began at 2 wk and progressively worsened until 5 wk. The percentage of myofibers with centrally located nuclei in mdm mice was significantly ( P < 0.01) increased at 2 and 6 wk by 4% and 17%, respectively, compared with controls. At 6 wk, mdm diaphragm twitch stress was significantly ( P < 0.01) reduced by 71%, time to peak twitch was significantly ( P < 0.05) reduced by 52%, and half-relaxation time was significantly ( P < 0.05) reduced by 57%. Isometric tetanic stress was significantly ( P < 0.05) depressed in 2- and 6-wk mdm diaphragms by as much as 64%. Length-tension relationships of the 2- and 6-wk mdm diaphragms showed significantly ( P < 0.05) decreased extensibility and increased stiffness. Slow myosin heavy chain expression was aberrantly favored in the mdm diaphragm at 6 wk. Our data strongly support early contractile and passive mechanical aberrations of the respiratory pump in mdm mice.
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Ren, Juan, David Cheneler, Mike Ward, and Peter Kinnell. "The Mechanical Behaviour of Silicon Diaphragms for Micromachined Capacitive Pressure Sensor." Advances in Science and Technology 54 (September 2008): 422–27. http://dx.doi.org/10.4028/www.scientific.net/ast.54.422.
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Single crystal silicon diaphragms are widely used as pressure sensitive elements in micromachined pressure sensors. When designing such a sensor it is usual to assume that the silicon is an isotropic material and the average elastic constants are used. However, the mechanical properties of single crystal silicon are orthotropic, and this has an important effect on the mechanical behaviour of silicon diaphragms under pressure. In this work, the deflections of orthotropic silicon circular diaphragms which are orientated against the (100) and the (110) planes are presented. It is found that by assuming silicon is isotropic material, the maximum stress is underestimated by 9.4% for (110) orientated silicon diaphragms, while the maximum stress is underestimated by 8% for (100) orientated silicon diaphragms. Therefore, when a silicon diaphragm is used in a MEMS sensor, the orthotropic properties should be taken into account for accuracy. Finally, the performance of a capacitive sensor is predicted by using finite element method.
Dissertations / Theses on the topic "Diaphragm – Mechanical properties"
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Singh, Bhajan. "The function of the human diaphragm as a volume pump and measurement of its efficiency." University of Western Australia. School of Biomedical and Chemical Sciences, 2004. http://theses.library.uwa.edu.au/adt-WU2004.0029.
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[Truncated abstract] The function of the diaphragm as a volume pump has not been adequately evaluated because there are no accurate methods to measure the volume displaced by diaphragm motion (ΔVdi). As a consequence, the work done, power output and efficiency of the diaphragm have not been measured. Efficiency of the diaphragm could be measured by relating the power output of the diaphragm to its neural activation. The aims of this thesis were to (a) develop a new biplanar radiographic method to measure ΔVdi and use this to evaluate the effect of costophrenic fibrosis and emphysema on ΔVdi, (b) develop a new fluoroscopic method to enable breath-by-breath measurements of ΔVdi, (c) evaluate a method for quantifying neural activation of the diaphragm, and (d) combine measurements of transdiaphragmatic pressure, ΔVdi, inspiratory duration and neural activation of the diaphragm to quantify the neuromechanical efficiency of the diaphragm
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Rawlinson, Patrick Theodore. "The Mechanical Properties of Submicron-Thick, Large-Area 3C-SiC Diaphragms." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1328296558.
Full textBook chapters on the topic "Diaphragm – Mechanical properties"
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Di Giovanni, Mario. "Mechanical Properties of Materials." In Flat and Corrugated Diaphragm Design Handbook, 12–20. Routledge, 2017. http://dx.doi.org/10.1201/9780203755969-3.
Full textConference papers on the topic "Diaphragm – Mechanical properties"
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Shen, Xingzhu, Qiang Qi, Quanxia Yang, and Shimin Wang. "Research on Mechanical Properties of Existing Station Structure While Diaphragm Wall Is Demolished during Construction." In Transportation Research Congress 2016. Reston, VA: American Society of Civil Engineers, 2018. http://dx.doi.org/10.1061/9780784481240.055.
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Chen, Zhibang, Wei Du, and Feng Zhao. "Silicon Carbide MEMS Capacitive Pressure Sensor for Harsh Environments." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64764.
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In this paper, we investigated a new capacitive pressure sensor structure on a silicon carbide (SiC) platform for high sensitivity and harsh environment operation capability. The superior material properties of SiC ensure robustness of the new sensor to withstand large-scale pressure at high temperature and in chemical/biological medium. The sensor structure consists of a circular SiC diaphragm suspended by four arms over a SiC substrate, with design to enable diaphragm to deflect nearly uniformly with applied pressure. This configuration results in improved sensing properties. With high sensitivity and operation capability in hostile environment, this new pressure sensor is promising for use in a wide range of applications such as automotive, nuclear station, aerospace, and oil/gas exploration, etc.
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Lee, Bong Joo, and J. R. Culham. "Effectiveness Analysis of Non-Mechanical Micro-Valvular Conduit in Single Phase Flow." In ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icnmm2012-73045.
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The non-mechanical valvular conduit, which uses no moving parts but instead relies on a complex geometry to regulate flow, is studied through a combination of numerical, computational and experimental methods. This study is based on using water as the fluid at standard state properties. A numerical model is developed to evaluate the effectiveness of the non-mechanical valve’s intricate geometry. Then computational simulations of the oscillating/pumping sequence of the valvular conduit are conducted to examine the effectiveness of the valve when placed in use for a diaphragm pump. Results demonstrate that the non-mechanical valvular conduit can be an effective application for a diaphragm pump at the micro or macro-scale without requiring valvular mechanics. In computational simulations, when non-mechanical valves are positioned at both the inlet and exit of a diaphragm, the positive circulation of fluid is enhanced by 38% which is sufficient to meet the thermal dissipation requirements of an Intel Pentium D processor (i.e. 130 W). In addition, the experimental results in steady state condition demonstrated that the valvular design regulates the flow direction by producing diodicity (a measure of favorable flow direction) of 2.44.
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Mane, Poorna P., Karla M. Mossi, and Robert G. Bryant. "Experimental Design and Analysis of Bimorphs as Synthetic Jet Diaphragms." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-14051.
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Synthetic jet actuators are promising Active Flow Control (AFC) devices which could lead to saving millions of dollars in fuel consumption each year. The Bimorph piezoelectric actuators are an attractive alternative to other type of actuators as active diaphragms and are the focus of this work. Among the properties of a Bimorph actuator, a number of geometrical and physical external factors may have an effect on its performance as a synthetic jet actuator. Using statistical tools some of the physical and geometrical factors are evaluated as independent variables that may have an effect on the synthetic jet peak velocity, the dependent variable. Among the factors studied are the geometry of the synthetic jet cavity, the driving signal used to operate the active diaphragm, and the effect of a pressure gradient on the device. Among the six factors considered, the driving signal was found to have the highest effect on the peak jet velocity, and the factor of frequency proved to have a smaller effect. The cavity geometrical parameters were also relevant, a smaller orifice and a smaller cavity produce higher peak jet velocities. An adverse pressure gradient was also found to have a significant effect on peak jet velocity, diminishing its magnitude with increasing pressure.
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Kagerer, Markus, Kenji L. Eiler, Franz Irlinger, and Tim C. Lueth. "Intelligent Combination of Batch Fabrication With Rapid Prototyping Techniques for a Drop-on-Demand Microdrop Generator." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-85854.
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A fluidic experimentation platform, consisting of a piezoelectrically driven microdrop generator which is mounted on a quick-action clamping device, is introduced. Microdrop generators are playing an increasingly important role in many industries. Even though their beginnings were in the printing and coating sector, their strengths are more and more used in other sectors. The wide variety of properties of the fluids like molten polymers, dispersions, or monomers usually require a redesign of the microdrop generator for each application to achieve drops of the size, with the speed, and uniformity that are needed. Therefore, the use of rapid prototyping (RP) techniques for the adaption of microdrop generators to new boundary conditions is indispensable. The presented microdrop generator is based on the diaphragm design. A silicon base plate includes the fluidic components. The number of nozzles is three. Even if one nozzle is clogged two other nozzles are working. The diaphragm is made of borosilicate glass. On top of the diaphragm a piezoelectric transducer is glued. The piezoelectric transducer and the diaphragm form a bimorph actuator. Since only the borosilicate glass and the silicon are in contact with the fluid the assembly is highly chemical resistant to aggressive media. Thus, a very broad range of fluids is ejectable. Besides the laser as main tool a dicing saw is involved in the process flow. Investigations for the optimum machining parameters are presented. In this project four equal microdrop generators respectively 12 nozzles and one further silicon base plate for further quality inspection of the whole batch are manufactured simultaneously. They serve as a good basis for fluidic experiments. Only six process steps are necessary to fabricate one microdrop generator within 25 min. Up to 16 microdrop generators can be batch fabricated in a 4″ process chain with rapid prototyping techniques. The realized quick-action clamping device supports a rapid exchange of the microdrop generators and enables future technologies. Here, the electrical and the fluidic connection of the microdrop generator are realized. The microdrop generator is inserted into a groove and is at the same time fluidically and electrically connected via four spring contacts. Special feature is that no gluing or soldering processes are necessary. The device is constructed in a modular way to add further components like a heating cartridge or a fluid reservoir. Overall, the exchange of one microdrop generator can be realized within one minute. The use of the batch fabricated microdrop generator in combination with the presented quick-action clamping device guarantees an efficient execution of fluidic experiments.
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Shahinpoor, Mohsen. "Smart Ionic Polymer Conductor Composite Materials as Multifunctional Distributed Nanosensors, Nanoactuators and Artificial Muscles." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-79394.
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Basic recent results, properties and characteristics of ionic polymer conductor composites (IPCC) and ionic polymer metal composites (IPMC) as biomimetic distributed nanosensors, nanoactuators, nanotransducers and artificial muscles are briefly discussed in this paper. In particular the paper first starts with some fundamental considerations on biomimetic distributed nanosensing and nanoactuation and then expands its coverage to some recent advances in manufacturing techniques, force optimization, 3-D fabrication of IPMC’s, recent modeling and simulations, sensing and transduction and product development. The paper also covers some recent industrial and medical applications including a multi-fingered grippers (macro, micro, nano), biomimetic robotic fish and caudal fin actuators, diaphragm micropump, multi-string musical instruments, linear actuators made with IPMC’s, IPMC-based data glove and attire, IPMC-based heart compression/assist devices and systems, wing flapping flying system made with IPMC’s and a host of others.
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SadAbadi, Hamid, Arvind Chandrasekaran, Muthukuraman Packirisamy, and Rolf Wuthrich. "Simulation and Dynamic Characterization of a 3-Layer Piezo-Actuated Valveless Micropump System." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-40704.
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In order to design the valveless micropump with a Piezo actuator, it is essential to understand the dynamic properties of the actuating system. Besides several other considerations in designing of microfluidic systems, the efficiency of valveless micropumps also strongly depends on parameters of the actuation system including the actuation frequency. Cleary, higher displacement of the diaphragm results in higher output flow rate of the pump. Thus, studying the dynamic behavior of the actuation system forms one of the important considerations for the design of micropumps. Three different models of the actuating system for the fabricated micropump system are proposed with different boundary conditions and are simulated by finite element method using ANSYS. Comparison of the experimental results and the simulation results of the natural frequencies of the system shows that the proposed simulation method can also be now used as a tool to optimize the design of the actuation system in terms of natural frequency of the system.
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Kagerer, Markus, Dominik Rumschoettel, Franz Irlinger, and Tim C. Lueth. "Fabrication and Application of a Chemical Resistant Low-Cost Microdrop Generator." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62640.
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This paper introduces a chemical resistant piezoelectrically driven microdrop generator which can be fabricated in a cost and time saving manner by using rapid prototyping techniques. Thus it is especially suitable as an experimentation platform. For the adaption of microdrop generators to various fluids, an experimentation platform is needed which allows the rapid change of geometry, dimensions, and material parameters of the microdrop generator. The size of the nozzle, the geometry of the pumping chamber, and the thickness of the used piezo-transducer have to be adaptable to various fluids to achieve drops of the size, speed, and uniformity that are needed. This microdrop generator uses a sandwich structure which consists of a silicon wafer, a Pyrex diaphragm, and a PZT transducer. A pumping chamber is milled into the silicon by laser micromachining; and the Pyrex is anodically bonded on top of the silicon plate to seal off the pumping chamber. The piezo-transducer is then glued to the diaphragm with an epoxy adhesive to obtain a bimorph actuator. When electrically driven, the actuator bends inwards into the pumping chamber which in turn creates a pressure wave inside the chamber that finally leads to the ejection of a drop out of the lateral nozzle. Since only the Pyrex and the silicon are in contact with the fluid the assembly is very resistant to aggressive media like solvents, adhesives, or acids. The thickness of the piezo-actuator can be varied according to the intended application. Depending on the piezoceramic used, the operating temperature is up to 250 °C. Single- and multi-nozzle arrays as well as the integration of a heated fluid reservoir can be realized. The drop volume is set by proper dimensioning of the microdrop generator. Manufacturing, assembly, and interconnection technology of the droplet generator will be described later in this paper. The electro-mechanical behaviour of the droplet generator is analyzed by determining the step response function and by measuring the frequency-dependant impedance. For the first fluidic validation of the experimentation platform, isopropanol is used because of its well known properties. The relationship between drop velocity and drive voltage on the PZT transducer is established. Special attention is paid to the calculation of the microdrop generator material cost which only amounts to $25 for a multi-nozzle array. By using rapid prototyping techniques the microdrop generator is manufactured within 180 min. This shows the potential for a low-cost and rapidly producible experimentation platform.
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Chu, Chen-Hing, Tsung-Lin Chou, Chun-Te Lin, and Kuo-Ning Chiang. "Investigation of Packaging Effect of Silicon-Based Piezoresistive Pressure Sensor." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-14208.
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The silicon-based pressure sensor is one of the major applications in the MEMS device. Nowadays, the silicon piezoresistive pressure sensor is a mature technology in industry and its measurement accuracy is more rigorous in many advanced applications. In order to operate the piezoresistive pressure sensor in harsh environment, the silicone get is usually used to protect the die surface and wire bond while allowing the pressure signal to be transmitted to the silicon diaphragm. The major factor affecting the high performance applications of the piezoresistive pressure sensor is the temperature dependence of its pressure characteristics. Therefore, the thermal and packaging effects caused by the silicone gel behaviors should be taken into consideration to obtain better sensor accuracy and sensitivity. For this reason, a finite element method (FEM) is adopted for the sensor performance evaluation, and the thermal and pressure loading is applied on the sensor to study the output signal sensitivity as well as the packaging-induced signal variation, thermal/packaging effect reduction, and output signal prediction for the pressure sensors. The design parameters include silicon die size, silicone gel geometry and its material properties. The simulation results show that the smaller die size and the thicker die thickness can reduce the packaging-induced thermal effect. Furthermore, the different geometry of silicone gel also influences the sensitivity of pressure sensor.
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Mo, Changki, Daniel Arnold, William C. Kinsel, and William W. Clark. "Unimorph PZT Cymbal Design in Energy Harvesting." In ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2011. http://dx.doi.org/10.1115/smasis2011-5005.
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This paper presents power generation performance of unimorph PZT (lead zirconate titanate) cymbal harvesters optimally designed for the power requirements of a specific application. Proof-of-concept work has shown that the traditional cymbal design can be adapted to a new design that is capable of sustaining higher mechanical loads by replacing the piezoelectric plate with a unimorph circular piezoelectric diaphragm between the metal end caps. The unimorph circular diaphragm is constructed by bonding PZT to a steel substrate to provide increased strength. Additional work was performed to prepare the new cymbal design for large-scale implementation in a variety of applications. The parameters that affect energy harvesting performance for the cymbal structure are first optimized by parametric studies to produce optimum generated energy from a specific range of applied cyclic forces. Key parameters in the unimorph PZT cymbal design include the material properties and the dimensions of the end caps, the ratios of the diameters of the unimorph disc and the end cap cavity, and thickness ratio of the PZT layer and the substrate. Based on the optimized unimorph PZT cymbal structure, a specimen was then fabricated and tested on the load-frame to validate analytically predicted energy generating performance. The specimen was tested under a 1 Hz cyclic load of up to 2,100 N. The measured open circuit output voltages for two different load inputs were in accordance with the analytical prediction.