Mechanotransduction is fundamental to many sensory processes, including balance, hearing and motor co-ordination. However, for such an essential feature, the mechanism(s) that underlie it are poorly understood. The mechanotransducing stretch receptors that relay information on the tonicity and length of skeletal muscles have been well-defined, particularly at the gross anatomical level, in a wide variety of species, encompassing both vertebrates and invertebrates. To date, there exists a wealth of data describing them, anatomically, as well as good electrophysiological data from stretch receptors of some larger organisms. However, comparatively few studies have succeeded in identifying putative mechanotransducing molecules in such systems. Nonetheless, this class of sensory mechanotransducers perhaps offer the best means of identifying molecules that permit the stretch-sensitivity of such endings, revealing new information about the underlying mechanisms of stretch receptors, and mechanoreceptors more generally. However, a different approach is clearly needed; a theoretical approach, utilising mathematical modelling, offers a powerful means of pooling the current wealth of knowledge on the reported electrophysiological behaviour of muscle stretch receptors. This study, therefore, develops an extended theoretical model of a stretch receptor system in order to reproduce, in silico, the reported behaviour of both vertebrate and invertebrate stretch receptors, within the same modelling environment, thus enabling the first quantitative framework for comparing these data, and moreover, making predictions of the likely roles of specific molecular entities within a stretch receptor system. Subsequently, this study utilises a model in vivo system to test these theoretical predictions. The genetic toolbox of D. melanogaster offers a wide range of tools that are extremely suitable for identifying mechanotransducing molecules in stretch receptors. However, very little is currently known about such endings in this organism. This study, therefore, firstly characterises a putative stretch receptor organ in larval Drosophila, the dbd neuron, via a novel experimental approach. It is shown that this neuron exhibits known properties of stretch receptors, as previously observed in other, similar organs. Furthermore, these observations bear out the predictions of the mathematical model. Having defined the dbd neuron as a muscle stretch receptor, pharmacological and genetic assays in this system, combined with predictions from the mathematical model, identify a key role for the recently-discovered DmPiezo protein as an amiloride-sensitive, mechanically-gated sodium channel (MNaC) in dbd neurons, with TRPA1 also acting in this system in a supporting role. These data confirm the essential role of an MNaC in mechanosensory systems, but also supply important evidence that, whilst the electrophysiological mechanisms in stretch receptors are remarkably similar across taxa, different species likely employ various molecular mechanisms to achieve this.

The piezo-phototronics effect is the three way coupling of semiconductor properties, photonics and piezoelectricity in the same material. Research on piezo-phototronics effect has illustrated its application on various Zinc Oxide (ZnO) nanowire based devices, yet a systematical study with comprehensive theoretical model is still missing. Here we have designed experiments on wider variety of materials to investigate the mechanism of the piezo-phototronics effect, and then built up a theoretical model for more thorough understanding. Experimental results are shown for Cadmium Sulfide (CdS) photodetectors for visible light detection, inorganic/organic hybrid Light Emitting Diodes (LEDs) and LED arrays, and it is demonstrated that strain can significantly tune the performance of these optoelectronic devices. Theoretical methodologies are proposed for Metal-Semiconductor-Metal (MSM) structure and p-n junctions, including analytical solutions and Finite Element Method (FEM) simulations. For Schottky contacts in photodetectors, barrier height change is determined as the main reason for the effect, and an exponential relationship between applied external strain and the device current is discovered, and is qualitatively confirmed from experimental results. For p-n junctions in LEDs, change in size of depletion region under strain is credited for the current change, and a charge channel is predicted for large strain, which gives explanation for the observed gigantic enhancement of light emission efficiency in experiments.

A novel segmented electrodes linear ultrasonic motor (USM) was developed. Using a planar vibration mode concept to achieve elliptical motion at the USM drive-tip, an attempt to decouple the components of the drive-tip trajectory was made. The proposed design allows greater control of the drive-tip trajectory without altering the excitation voltage. Finite element analyses were conducted on the proposed design to estimate the performance of the USM. The maximum thrust force and speed are estimated to be 46N and 0.5370m/s, respectively. During experimental investigation, the maximum thrust force and speed observed were 36N and 0.223m/s, respectively, at a preload of 70N. Furthermore, the smallest step achievable was 9nm with an 18μs impulse. Nevertheless, the proposed design allowed the speed of the USM to vary while keeping the thrust force relatively constant and allowed the USM to achieve high resolution without a major sacrifice of thrust force.

A novel segmented electrodes linear ultrasonic motor (USM) was developed. Using a planar vibration mode concept to achieve elliptical motion at the USM drive-tip, an attempt to decouple the components of the drive-tip trajectory was made. The proposed design allows greater control of the drive-tip trajectory without altering the excitation voltage. Finite element analyses were conducted on the proposed design to estimate the performance of the USM. The maximum thrust force and speed are estimated to be 46N and 0.5370m/s, respectively. During experimental investigation, the maximum thrust force and speed observed were 36N and 0.223m/s, respectively, at a preload of 70N. Furthermore, the smallest step achievable was 9nm with an 18μs impulse. Nevertheless, the proposed design allowed the speed of the USM to vary while keeping the thrust force relatively constant and allowed the USM to achieve high resolution without a major sacrifice of thrust force.

Master of Science / Department of Kinesiology / Steven W. Copp / Mechanical signals within contracting skeletal muscles contribute to the generation of the exercise pressor reflex; an important autonomic and cardiovascular control mechanism. In decerebrate rats, GsMTx4, a mechanically–activated channel inhibitor that is partially selective for piezo channels, was found recently to reduce the pressor response during static hindlimb muscle stretch; a maneuver used to investigate the mechanical component of the exercise pressor reflex (i.e., the mechanoreflex). However, the effect was found only during the very initial phase of the stretch when muscle length was changing which may have reflected the inhibition of rapidly-deactivating piezo 2 channels and the fact that different mechanically-activated channels with slower deactivation kinetics evoked the pressor response during the static phase of the maneuver. We tested the hypothesis that in decerebrate, unanesthetized rats, GsMTx4 would reduce the pressor response throughout the duration of a 30 second, 1 Hz dynamic hindlimb muscle stretch protocol. We found that the injection of 10 µg of GsMTx4 into the arterial supply of a hindlimb reduced the peak pressor response (control: 15±4, GsMTx4: 5±2 mmHg, p<0.05, n=8) and the pressor response at multiple time points throughout the duration of the stretch. GsMTx4, however, had no effect on the pressor response to the hindlimb arterial injection of lactic acid. Moreover, the injection of GsMTx4 into the jugular vein (a systemic control, n=5) or the injection of saline into the hindlimb arterial supply (a vehicle control, n=4) had no effect on the pressor response during dynamic stretch. We conclude that GsMTx4 reduced the pressor response throughout the duration of a 1 Hz dynamic stretch protocol which may have reflected the inhibition of piezo 2 channels throughout the dynamic stretch maneuver.

To solve the problem of limited tactile sensing in humanoid robotics as well as provide for future planned mechanical prostheses, an innovative tactile sensor system was created and embedded into two realistic-looking artificial skin gloves. These artificial skin tactile sensors used small piezoelectric ceramic disks to measure applied force at multiple points on each glove. The gloves were created using silicone rubber to simulate both the texture and look of human skin, while maintaining both flexibility and durability. The sensor outputs were buffered by high-impedance voltage-following operational amplifiers, and then read sequentially using a multiplexing scheme by a microcontroller. Sensor data were sent via USB to a computer, where a graphical user display was created to show the tactile information in real time. These prototypes successfully demonstrated the viability of small piezoelectric elements embedded in silicone rubber for use in creating flexible and elastic tactile sensors.

The stadium, in its purest form, is a structure that holds tiered seating arrangements built for mass viewing of sports, competitions, and public events. However, over the years, it has become much more than that. The stadium provides the spiritual need of community, allowing individuals to connect to others by sharing common beliefs and goals. This allows the stadium to become a source of civic pride to the people it serves. This combination of purpose and pride makes the stadium one of the most important archetypes ever created. It is the physical representation of human connectivity, a city's symbolic soul; the modern day cathedral. A symbiotic relationship is formed between the stadium and the public. In the modern era, viewing live sports has become big business. Taking advantage of the situation, team owners have designed stadiums to capitalize financially as much as possible. These newly designed stadiums, along with the rise of the automobile, have been moved from downtown to the suburbs, providing owners more space for seats, larger parking lots, and ultimately more revenue. These larger, disconnected stadiums have led to waning attendance, heavy pollution, and an overall lack of use. The once spiritual experience of the arena has now been watered down as the stadium has become a detractor of public good. Sports leagues now run as unopposed monopolies, with each major league having approximately 30 teams. With supply low and demand high, private entities essentially blackmail the public into building and funding stadiums to attract highly coveted sports teams. Desperately desiring to call a team their own, the public agrees to the deal. The end result is that the public funds a major project that provides no socioeconomic benefit to anyone other than the teams owner. The once symbiotic relationship between the stadium and the city has become perverted. Although public subsidies are now frowned upon due to the growing awareness of the damage they cause cities, the major sports leagues will always have a significant hold over the distribution of teams and demand will always remain high. Therefore, if the public continues to foot the bill, it is up to the architect to find a balance between both public and private benefits through design. We must create a stadium that functions as a revenue generating event venue, as well as a public serving entity that enriches the community around it and repair the once great harmony between the public and their stadium. My Thesis will look at designing a public soccer stadium in downtown Washington D.C. This is Public Gains: A Stadium for the People. / Master of Architecture

The subject of my diploma thesis is design and realization of a five strings electric violin. This work builds on my theoretical diploma work named Development of the violin up to the present. The body of the violin is made of solid wood (beech) as same as the chin rest, fingerboard and bridge (walnut). The body is white coloured and varnished. In the left rib is placed el. sound output – 6.3 mm jack. The violin is equipped with piezo pickup Shadow SH SV1. Removable part of the violin is the shoulder rest. It has two support points.

This master's thesis deals with systems and technology of high speed weigh in motion stations. The main task is to evaluation of accuracy different sensor installations of weight in motion stations. A part of this thesis is an analysis of different sensor types, which are used for stations equipped with technology for enforcement, and evaluation of accuracy of axle distance measurement.

Dizertační práce je obecně zaměřena na problematiku mikroskopie atomárních sil (AFM), a to jak vývoje částí těchto mikroskopů, tak i jejich obecnému využití v oblasti výzkumu povrchů, ultratenkých vrstev a nanostruktur. Na Ústavu fyzikálního inženýrství jsou vyvíjena zařízení umožňující aplikovat uvedenou mikroskopickou metodu. V těchto mikroskopech jsou využívány piezoelektrické motory pro zajištění pohybu vzorku a ladicích zrcátek v optickém detekčním systému. Práce se v části věnované vývoji AFM zabývá studiem parametrů řídicích pulzů za účelem optimalizace funkce těchto komponent. Měřením vlivu tvaru pulzů a opakovací frekvence byl jejich pohyb optimalizován z hlediska stability a rychlosti posuvu. V části věnované výzkumu povrchů byly experimentálně zkoumány morfologické změny ultratenkých vrstev zlata na povrchu oxidu křemičitého za zvýšených teplot. Bylo zjištěno, že vhodná povrchová modifikace způsobuje vznik preferenčních trhlin ve vrstvě zlata. Řízeným rozdělením polykrystalické vrstvy na oddělené oblasti je možné významně ovlivnit proces tvorby ostrůvků zlata vznikajících při žíhání. S využitím metod elektronové litografie je možná příprava uspořádaných polí zlatých ostrůvků o velikostech 50 – 400 nm. Dále bylo ukázáno, že zvýšením teploty žíhání na 1000 °C dochází k postupnému zanořování ostrůvků zlata do povrchu. Tento jev je pravděpodobně způsoben přesunem oxidu křemičitého z oblasti pod zlatým ostrůvkem do těsného okolí vzniklého kráteru, kde tvoří tzv. límec. V těchto studiích vedle metody AFM byla s výhodou používána rovněž elektronová mikroskopie (SEM).