Segui questo link per vedere altri tipi di pubblicazioni sul tema: Machinery.
Tesi sul tema "Machinery"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 saggi (tesi di laurea o di dottorato) per l'attività di ricerca sul tema "Machinery".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi le tesi di molte aree scientifiche e compila una bibliografia corretta.
1
Herman, Paul Andrew. "Improvement of surface finish quality in peripheral milling VIA precision compensation for cutter runout." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/16696.
Testo completo
2
KöÅ, er Hür 1976. "Development of magnetic induction machines for micro turbo machinery." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8119.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.<br>Includes bibliographical references.<br>This thesis presents the nonlinear analysis, design, fabrication, and testing of an axial-gap magnetic induction micro machine, which is a two-phase planar motor in which the rotor is suspended above the stator via mechanical springs, or tethers. The micro motor is fabricated from thick layers of electroplated NiFe and copper, by our collaborators at Georgia Institute of Technology. The rotor and the stator cores are 4 mm in diameter each, and the entire motor is about 2 mm thick. During fabrication, SU-8 epoxy is used as a structural mold material for the electroplated cores. The tethers are designed to be compliant in the azimuthal direction, while preventing axial deflections and maintaining a constant air gap. This enables accurate measurements of deflections within the rotor plane via a computer microvision system. The small scale of the magnetic induction micro machine, in conjunction with the good thermal contact between its electroplated stator layers, ensures an isothermal device which can be cooled very effectively. Current densities over 109 A/m2 simultaneously through each phase is repeatedly achieved during experiments; this density is over two orders of magnitude larger than what can be achieved in conventional macro-scale machines. More than 5 Nm of torque is obtained for an air gap of about 5 zm, making this micro motor the highest torque density micro-scale magnetic machine to date. About 0.3 buNm for the large air gap of 70 m is also achieved in systematic tests that reveal the influence of strong eddy-currents and associated nonlinear saturation within the micro motor.<br>(cont.) Eddy-current effects are modeled using a finite-difference vector potential formulation. Its results demonstrate the presence of flux crowding on the stator surface, which leads to heavy saturation. To capture saturation effects, a fully nonlinear finite-difference time-domain simulation is developed to solve Maxwell's Equations within the computational space of the micro machine. To mitigate the inherent stiffness in the partial differential equations, the speed of light is artificially reduced by five orders of magnitude, taking special care that assumptions of magnetoquasistatic behavior are still met. The results from this model are in very good agreement with experimental data from the tethered magnetic induction micro motor.<br>by Hür KöÅer.<br>Ph.D.
3
Tombs, George 1956. "Man the machine : a history of a metaphor from Leonardo da Vinci to H. G. Wells." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84203.
Testo completoAbstract (sommario):
During the Italian Renaissance, artists and anatomists compared man to various mechanical devices, in an attempt to uncover knowledge about the structure and processes of the human body. In so doing, they drew on ancient Greek notions of instrumentality and proportion. During the early Scientific Revolution, the metaphor of Man the machine played a key role in the development of mechanistic philosophy. During the Enlightenment, it served views on materialism and atheism. By the nineteenth century, when the Industrial Revolution was in full swing, a fundamental change in the relationship of man to machine had come about. Whereas, for Protagoras, man had been the measure of all things, now suddenly the machine was the standard by which the capacities and limits of man were judged. Man the machine was a key feature in the development of the totalitarian ideology of Communism. Moreover, for over a century now, the technocratic viewpoint has guided many technological innovations. Tracing a history of this metaphor, through Leonardo, Vesalius, Harvey, Descartes, Hobbes, Leibniz, La Mettrie, d'Holbach, Marx and Wells, places man's relationship with technology and his gradual loss of identity since the Renaissance in a new context.
4
Moss, T. R. "Rotating machinery reliability." Thesis, Loughborough University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311046.
Testo completo
5
Udovychenko, N. M. "Machinery vibration diagnostics." Thesis, Сумський державний університет, 2013. http://essuir.sumdu.edu.ua/handle/123456789/33874.
Testo completoAbstract (sommario):
Vibration is a process that can not be measured, unlike its parameters. The machine can have high levels of vibration for three reasons:
– there is a strong source of vibration inside the machine;
– during spreading between source of vibration and the point of observation, vibration weakly damped or even increases due to good conductivity and transparency of the surrounding structures;
– there are two previous reasons simultaneously.
For solving the first problem we have to explore the physical nature of vibration inside the machine. For solving the second problem it's necessary to investigate the spread of vibrations out of the construction.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/33874
6
Filla, Reno. "Operator and Machine Models for Dynamic Simulation of Construction Machinery." Licentiate thesis, Linköping : Linköpings universitet, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-4092.
Testo completo
7
Kivistö-Rahnasto, Jouni. "Machine safety design : an approach fulfilling European safety requirements /." Espoo [Finland] : Technical Research Centre of Finland, 2000. http://www.vtt.fi/inf/pdf/publications/2000/P411.pdf.
Testo completo
8
Angola, Enrique. "Novelty Detection Of Machinery Using A Non-Parametric Machine Learning Approach." ScholarWorks @ UVM, 2018. https://scholarworks.uvm.edu/graddis/923.
Testo completoAbstract (sommario):
A novelty detection algorithm inspired by human audio pattern recognition is conceptualized and experimentally tested. This anomaly detection technique can be used to monitor the health of a machine or could also be coupled with a current state of the art system to enhance its fault detection capabilities. Time-domain data obtained from a microphone is processed by applying a short-time FFT, which returns time-frequency patterns. Such patterns are fed to a machine learning algorithm, which is designed to detect novel signals and identify windows in the frequency domain where such novelties occur. The algorithm presented in this paper uses one-dimensional kernel density estimation for different frequency bins. This process eliminates the need for data dimension reduction algorithms. The method of "pseudo-likelihood cross validation" is used to find an independent optimal kernel bandwidth for each frequency bin. Metrics such as the "Individual Node Relative Difference" and "Total Novelty Score" are presented in this work, and used to assess the degree of novelty of a new signal. Experimental datasets containing synthetic and real novelties are used to illustrate and test the novelty detection algorithm. Novelties are successfully detected in all experiments. The presented novelty detection technique could greatly enhance the performance of current state-of-the art condition monitoring systems, or could also be used as a stand-alone system.
9
Seaman, Matthew N. J. "Targeting machinery for adaptors." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339587.
Testo completo
10
Fenney, Lee. "Flexible high speed machinery." Thesis, Aston University, 1989. http://publications.aston.ac.uk/11882/.
Testo completoAbstract (sommario):
The thesis describes an investigation into methods for the design of flexible high-speed product processing machinery, consisting of independent electromechanically actuated machine functions which operate under software coordination and control. An analysis is made of the elements of traditionally designed cam-actuated, mechanically coupled machinery, so that the operational functions and principal performance limitations of the separate machine elements may be identified. These are then used to define the requirements for independent actuators machinery, with a discussion of how this type of design approach is more suited to modern manufacturing trends. A distributed machine controller topology is developed which is a hybrid of hierarchical and pipeline control. An analysis is made, with the aid of dynamic simulation modelling, which confirms the suitability of the controller for flexible machinery control. The simulations include complex models of multiple independent actuators systems, which enable product flow and failure analyses to be performed. An analysis is made of high performance brushless d.c. servomotors and their suitability for actuating machine motions is assessed. Procedures are developed for the selection of brushless servomotors for intermittent machine motions. An experimental rig is described which has enabled the actuation and control methods developed to be implemented. With reference to this, an evaluation is made of the suitability of the machine design method and a discussion is given of the developments which are necessary for operational independent actuators machinery to be attained.
11
Crane, Nathan B. "Compliant centrifugal clutches : design, analysis, and testing /." Diss., CLICK HERE for online access, 1999. http://contentdm.lib.byu.edu/ETD/image/etd223.pdf.
Testo completo
12
Thapa, Bhola. "Sand Erosion in Hydraulic Machinery." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-302.
Testo completoAbstract (sommario):
<p>The topic of this thesis is damage of hydraulic machinery due to sand erosion. This is a very broad topic in which all the aspects of design of hydraulic machinery namely material selection; mechanics of material and hydraulics are involved. The issue of sand erosion is equally important for operation and maintenance of hydropower plants.</p><p>The erosion damage of turbines of hydropower plants in Himalayan Rivers, in particular in Nepal, due to high sediment contents in river is a motivating factor for this research. The findings of this study are believed to help to reduce erosion of turbine components, increase their life time and improve maintenance procedure.</p><p>The objectives of this study are to:</p><p>1. Study the erosion process on different materials and compare lifetime of turbine material with hard surface coating.</p><p>2. Study the flow in the turbine and identify the region of highest velocity and acceleration where most serious sand erosion occurs.</p><p>3. Study erosion rate of turbine as a function of operating parameters (head and speed), particle characteristics and turbine material.</p><p>4. Assess loss of efficiency and to analyze repair method and repair interval that gives optimal economy of the hydropower plants.</p><p>The goals laid out in the objectives are achieved by understanding the theory of erosion of material through literature, investigating the nature of turbine damage from field observation and finally by experiments to study effect of variables of erosion rate and investigation of particle separation process in rotational flow.</p>
13
Edwards, S. "Fault diagnosis of rotating machinery." Thesis, Swansea University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636771.
Testo completoAbstract (sommario):
In this thesis, topics of importance to the fault diagnosis of rotating machinery in the power generation industry have been addressed, including a review of the relevant literature and an overview of the associated rotordynamics modelling and analysis techniques. For faults involving rotor-stator interaction it has been shown that the inclusion of torsion in mathematical models used for rotor-stator contract analyses can have a significant influence on the dynamic behaviour of the system. A 3 degrees-of-freedom model based on the Jeffcott rotor was developed and, for physically realistic systems, it was shown that very different results were obtained when including torsion, compared to when torsion was neglected, as has generally been the case in the past. An identification method for estimating both the excitation and flexible support parameters of a rotor-bearings-foundations system has been presented. Excitation due to both mass unbalance and a bent rotor were included in the analysis, which has been verified both in simulation and experimentally. The method has great practical potential, since it allows balancing to be performed using data obtained from just a single run-up or run-down, which has obvious benefits for field balancing. Using this single-shot balancing technique in experiment, vibration levels were successfully reduced by as much as 92% of their original levels. A bent rotor has been accurately identified in both simulation and experiment. It was also shown that including bend identification in those cases where only unbalance forcing was present in no way detracted from the accuracy of the estimated unbalance or foundation parameters. The identification of the flexible foundation parameters was generally successful, with measured and estimated parameters matching very closely in most cases. The identification method was tested for a wide range of conditions and proved suitably robust to changes in the system configuration, noisy data and modelling error.
14
Cockerill, Aaron. "Damage detection of rotating machinery." Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/105671/.
Testo completoAbstract (sommario):
Acoustic emission (AE) is an emerging technique for the condition monitoring of rotating machinery components, including both rolling element bearings and gears. Due to the high frequency range over which AE is sensitive to, AE potentially offers advantages for detection of incipient damage at an early stage of failure when compared to traditional techniques such as vibration. This thesis first investigates the effects of increased speed and load on the generation of AE within cylindrical roller bearings, and determines similarities and differences between AE and vibrational data. A traditional AE sensor was used in conjunction with a Dual Function Sensor (DFS) capable of recording both low frequency AE and vibration. It was shown that increasing speed has the greatest influence on the AE signals produced whereas the effect of load was limited. Order analysis of both AE and vibrational data also demonstrated that characteristic bearing defect frequencies are visible in the AE spectrum but not in the vibrational spectrum. Bearings with seeded defects upon the outer raceway were investigated under a fixed speed and it was found that load increased the energy within the signal frequency spectrum as the damaged increased. Two bearing life tests were also conducted, one accelerated to 12 hours and the second extended to over 2800 hours however as damage detection only occurred after significant damage had developed, it is concluded that AE of seeded defects indicate a false sensitivity. Both life tests were able to demonstrate that signal levels increase as damage propagates over the bearing raceway however it was not possible to determine any advantage of using AE over vibration. AE sensors were also applied to test rigs of increased complexity, including the monitoring a wind turbine planet bearing and a helical gear pair. AE was able to detect cracking of the shaft surface within the wind turbine bearing test rig which was mistaken for being an inner raceway failure, highlighting the difficulty in damage location. A tooth failure occurred during the testing of the helical gear pair however AE was not able to detect growing damage, instead only increasing in amplitude after the tooth had sheared off, similar to the detection from vibrational signals.
15
Ross, Katharina. "The mitochondrial protein import machinery." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/16024.
Testo completoAbstract (sommario):
Menschliche Mitochondrien enthalten etwa 1500 bis 2000 Proteine. Die meisten dieser Proteine werden im Zellkern kodiert und im Zytoplasma synthetisiert, und müssen daher über eine spezielle Maschinerie in die Mitochondrien transportiert werden. Obwohl mittlerweile viele Details über die Wirkungsweise dieser Proteinschleusen bekannt sind, wurden einige wichtige Aspekte des Proteinimports noch nicht ausreichend untersucht. Zum einen ist nicht bekannt, ob die einzelnen Importkomplexe einen Einfluss auf die mitochondrienvermittelte Apoptose haben. Weiterhin ist offen, welche genaue Rolle der Mitochondrienimport in der Pathogenese von Neisseria gonorrhoeae spielt. Außerdem ist unklar, ob Faktoren des Importapparates für die Aufrechterhaltung der mitochondrialen Morphologie notwendig sind. Um diese Fragestellungen zu untersuchen, wurden im Rahmen der vorliegenden Arbeit permanente Zelllinien hergestellt, in denen die Expression einzelner am Mitochondrienimport beteiligter Proteine mittels RNA-Interferenz (RNAi) inhibiert werden kann. Mithilfe dieser Zelllinien wurde getestet, ob die proapoptotischen Proteine Bax und Bak die Importmaschinerie benötigen, um in die äußere Mitochondrienmembran zu gelangen. Die Präsenz der beiden proapoptotischen Proteine in Mitochondrien während der Apoptose ist sehr entscheidend, da Bax und Bak in den Mitochondrien oligomerisieren und damit weitere Schritte der Apoptose einleiten. Im Widerspruch zu früheren Publikationen konnte hier gezeigt werden, dass die Translokation von Bax und Bak in die äußere Mitochondrienmembran unabhängig von Proteinimportfaktoren erfolgt. Der zweite Teil dieser Arbeit beschäftigt sich mit dem Einfluss mitochondrialer Importproteine auf die Pathogenese von Neisseria gonorrhoeae. Das Neisserienprotein PorB transloziert während der Infektion in die Mitochondrien der Wirtszelle und induziert Apoptose. Aufgrund der strukturellen Ähnlichkeit von PorB zu bestimmten Proteinen der äußeren Mitochondrienmembran wurde bisher angenommen, dass PorB diesen endogenen Proteinen auf ihrem Importweg in die äußere Mitochondrienmembran folgt. Überraschenderweise wurde im Rahmen dieser Arbeit entdeckt, dass PorB nicht von allen Komplexen der Importmaschinerie in den Mitochondrien erkannt wird. Infolgedessen transloziert es in die innere Mitochondrienmembran und wirkt dadurch toxisch auf die Wirtszelle. In einem weiteren Projekt wurde untersucht, welche Rolle die Proteinimportkomplexe der äußeren mitochondrialen Membran in der Aufrechterhaltung der Mitochondrienmorphologie spielen. Unter Verwendung der beschriebenen Zelllinien wurde entdeckt, dass in Abwesenheit des SAM (sorting and assembly) Importkomplexes die Struktur der inneren Mitochondrienmembran derangiert ist. Es wurden zudem Hinweise darauf gefunden, dass die Ursache für diesen Befund in einer Unterbrechung von Kontaktstellen zwischen den beiden Mitochondrienmembranen liegen könnte, für deren Aufrechterhaltung möglicherweise der SAM-Komplex verantwortlich ist. Die in dieser Arbeit vorgestellten Ergebnisse erlauben neue Einblicke in verschiedene Aspekte des Proteinimports in Mitochondrien. Zudem wurde mit der Entwicklung der stabilen Zelllinien ein neues Model geschaffen, anhand dessen in Zukunft weitere Detail des mitochondrialen Proteinimports erforscht werden können.<br>Human mitochondria comprise about 1500 to 2000 proteins. While only 13 proteins are encoded by the mitochondrial DNA the vast majority of mitochondrial proteins is encoded in the nucleus, synthesized in the cytosol, and translocated into mitochondria by a special protein import machinery. Although many details are now known about its function several important aspects of protein import in mitochondria were not unraveled yet. To begin with, the influence of the different mitochondrial import complexes on apoptosis is not known. Further, the exact role of the protein import machineries in mitochondria in the pathogenesis of Neisseria gonorrhoeae has not been clarified yet. Moreover, the question whether factors involved in protein import are required for the maintenance of the mitochondrial morphology is still unsolved. In order to address these open issues, permanent cell lines were generated within the frame of the present thesis in which the expression of single proteins implicated in mitochondrial import can be inhibited via RNA interference (RNAi). Using these cell lines, it was investigated whether the proapoptotic proteins Bax and Bak require the import machinery in order to gain access to the outer mitochondrial membrane. The presence of both proapoptotic proteins in mitochondria is essential during apoptosis as Bax and Bak oligomerize in the outer mitochondrial membrane leading to the execution of apoptosis. In contrast to earlier publications, results presented here prove that the translocation of Bax and Bak into the outer mitochondrial membrane occurs independent of its import machineries. The second part of this thesis explores the influence of mitochondrial import proteins on the pathogenesis of Neisseria gonorrhoeae. The neisserial protein PorB translocates into the mitochondria of host cells during infection and induces apoptosis. Because of structural similarities of PorB to a certain class of proteins in the outer mitochondrial membrane, it was assumed that PorB would follow the import pathway of these endogenous proteins into the outer mitochondrial membrane. Surprisingly, it was found within the present study that PorB is not recognized by all complexes implicated in this import pathway. As a consequence, it translocates into the inner mitochondrial membrane to exert its toxic effect on the host cell. In a further project, the role of import complexes of the outer mitochondrial membrane in the maintenance of the mitochondrial morphology was investigated. Using the described cell lines, it was found that in the absence of the SAM (sorting and assembly) import device, the structure of the inner mitochondrial membrane was disrupted. Further, evidence was found that the reason for this phenotype could be an interruption of contact sites between the two mitochondrial membranes, whose preservation possibly requires the SAM complex. The results presented here allow new insights into different aspects of mitochondrial protein import. Further, with the development of the stable cell lines a new model was generated that will allow future investigations on details about mitochondrial protein import.
16
Zhang, Cheng. "Defect detection and life prediction of rolling element bearings." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17658.
Testo completo
17
Cho, Junhee. "Dynamic modeling and analysis for swash-plate type axial pump control utilizing indexing valve plate /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9974614.
Testo completo
18
Sandbakken, Egil Christoffer. "Marine Machinery Systems - Tools and Architecture." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11614.
Testo completoAbstract (sommario):
The thesis presents tools and architecture regarding design of marine MSs in OSVs. It enlightens important aspects regarding the design based on a research study, and proposes a design methodology consisting of tools and architecture. From the research studies in chapter 2 it becomes clear that the most common propulsion system today for platform supply vessels (PSV) is the diesel-electric (DEL) propulsion system. Other concepts such as; dual fuel engines, Voith Schneider Propellers (VSP), hybrid systems, fuel cell power, wind power, nuclear power, and jet propulsion exist today but is not yet considered typical solutions. The research study in chapter 5, regarding current status on tools and architecture, shows that it exist very few dedicated and sophisticated tools and methodologies regarding early-design of MSs onboard OSVs. However, exceptions such as the software package GES, developed by TNO in Holland, were found and it is considered the most promising tool yet based on this study. GES share the same design philosophy as the proposed tool in chapter 8, which is regarding the MS as an energy system where power flow through components is modeled with respect to the bond graph theory. By utilizing the bond graph theory, unified interfacing is introduced. This approach is applicable in any energy domain and the variables describing the energy or power are kept in a general form; effort and flow. The proposed methodology, in chapter 7, presents structure and methods regarding the design process such as; concurrent engineering, hierarchical MS breakdown structure, component library scheme, and model documentation framework. The thesis presents, in chapter 8, a MS mock-up with a hierarchical system structure and unified interfacing between components. The mock-up is flexible in terms of sub-system or component reconfigurations and it allows for energy domain-independent performance analysis which is exemplified in chapter 8.5 and 8.6. The MS mock-up is considered far from complete in terms of user-friendliness, sub-system description, and component description, but it portraits trend lines regarding performance which are similar to what one may find by analyzing real MSs, which is considered the goal for developing this mock-up. The presented mock-up and methodologies are meant to exemplify how one can approach this challenge.
19
Zirkelback, Nicole Lisa. "Ritz series analysis of rotating machinery." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17562.
Testo completo
20
Gutierrez-Wing, Enrique Simon. "Modal analysis of rotating machinery structures." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409293.
Testo completo
21
Hameister, Heike. "Mathematical models for DNA replication machinery." Thesis, University of Aberdeen, 2012. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=186178.
Testo completoAbstract (sommario):
DNA replication and associated processes take place in all living organisms with the same constitutions. The knowledge of the duplication process, chromatin building and repair mechanisms has increased explosively over the last years, but the complex interplay of different proteins and their mechanisms are not conceived properly. During DNA replication, the DNA has to be unpacked, duplicated and finally repacked into chromatin. These steps require different proteins, e.g. new histone proteins on demand to secure an error-free and undelayed DNA replication. This thesis includes different mathematical models for DNA replication, repair and chromatin formation, which are based on experimental results. Three models of chromatin formation provide a simplified description of histone gene expression and protein synthesis during G1/S/G2 phase and include the contribution of different regulatory elements. Furthermore, all models present two different mechanisms of regulation to test possible scenarios of newly synthesised histones and free DNA binding sites. The basic model presents a single histone gene, which codes for a single histone protein. The stem-loop binding protein (SLBP) acts as a master regulator, which is only present during S phase. Different analyses of early S-phase, over- and underexpressed replication and the down-regulation of SLBP proof the model under extreme conditions. This basic model serves as a template for further scenarios with several genes and different histone families. For this, a second model is realised to simulate imbalances in the histone mRNA synthesis and translation. Additionally, a third model tests a gene knock-out and mRNA silencing. The initial histone model is able to qualitatively reproduce experimental observations and shows basic regulatory principles. The adaptation with several genes and different histone families presents qualitatively different system responses for the discussed regulatory mechanisms and illustrates the ability to compensate the effect of mRNA silencing.
22
鄭俊強 and Chun-keung Cheng. "The machinery import market in China." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1992. http://hub.hku.hk/bib/B31265236.
Testo completo
23
Jenkins, Michael David. "Active control of periodic machinery vibrations." Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.480701.
Testo completo
24
Gouvinhas, Reidson Pereira. "Design methods for production machinery companies." Thesis, Cranfield University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266983.
Testo completo
25
McCarthy, Daniel Joseph. "Vibration-based diagnostics of reciprocating machinery." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/10823.
Testo completo
26
Walker, Ryan. "Localising imbalance faults in rotating machinery." Thesis, Cranfield University, 2013. http://dspace.lib.cranfield.ac.uk/handle/1826/8606.
Testo completoAbstract (sommario):
This thesis presents a novel method of locating imbalance faults in rotating machinery through the study of bearing nonlinearities. Localisation in this work is presented as determining which discs/segments of a complex machine are affected with an imbalance fault. The novel method enables accurate localisation to be achieved using a single accelerometer, and is valid for both sub and super-critical machine operations in the presence of misalignment and rub faults. The development of the novel system for imbalance localisation has been driven by the desire for improved maintenance procedures, along with the increased requirement for Integrated Vehicle Health Management (IVHM) systems for rotating machinery in industry. Imbalance faults are of particular interest to aircraft engine manufacturers such as Rolls Royce plc, where such faults still result in undesired downtime of machinery. Existing methods of imbalance localisation have yet to see widespread implementation in IVHM and Engine Health Monitoring (EHM) systems, providing the motivation for undertaking this project. The imbalance localisation system described has been developed primarily for a lab-based Machine Fault Simulator (MFS), with validation and verification performed on two additional test rigs. Physics based simulations have been used in order to develop and validate the system. An Artificial Neural Network (ANN) has been applied for the purposes of reasoning, using nonlinear features in the frequency domain originating from bearing nonlinearities. The system has been widely tested in a range of situations, including in the presence of misalignment and rub faults and on a full scale aircraft engine model. The novel system for imbalance localisation has been used as the basis for a methodology aimed at localising common faults in future IVHM systems, with the aim of communicating the results and findings of this research for the benefit of future research. The works contained herein therefore contribute to scientific knowledge in the field of IVHM for rotating machinery.
27
Ward, Jennifer. "Tool development to study ubiquitination machinery." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/43327.
Testo completoAbstract (sommario):
Ubiquitination is a diverse post-translational modification, involved in a plethora of eukaryotic processes. At least three different enzymes are required for ubiquitination to occur: an ubiquitin-activating enzyme (E1), an ubiquitin-conjugating enzyme (E2) and an ubiquitin ligase (E3). Conversely, deubiquitinating enzymes (DUBs) regulate the removal of ubiquitin modifications. Together, this enzymatic machinery facilitates a wide array of ubiquitin modifications and further ubiquitin-like modifications. Such modifications play a significant role in the regulation of vital biological processes including proteasomal degradation, DNA damage response (DDR) and NF-κB signalling. Ubiquitination machinery can be studied using a chemical proteomics approach. Activity-based probes (ABPs) which covalently trap enzymes can be employed. Such probes possess bioorthogonal handles, which on ligation to complementary reporter groups enable enrichment of probe-enzyme complexes prior to LC-MS/MS, western blot, or fluorescent analysis. The design, synthesis, and development of six inhibitor-inspired ABPs for ubiquitin machinery is described. Both small molecule and peptide probes were explored, and assessed for their ability to act as ubiquitin machinery probes both in intact cells and cell lysate. Spike-in SILAC methodology was employed to quantify probe targets under competitive conditions against parent inhibitors, and in a DNA damage response model. An alternative to using literature inhibitors is to derive novel starting points for tool design through a fragment-based drug discovery approach. A high throughput screen against the minimal catalytic core of HOIP, an E3 ligase, is described together with subsequent validation and characterisation of hit fragments by waterLOGSY NMR and Micro-scale thermophoresis, and crystallography attempts. Finally, a model system for the structural analysis of transient enzyme complexes is explored, to further our understanding of these interactions and ultimately to assess the applicability of these complexes for future drug discovery. The design and synthesis of a maleimide trap is described, along with its application to covalently trap an Ub-E2-E3 complex.
28
Sinha, Jyoti K. "Health monitoring techniques for rotating machinery." Thesis, Swansea University, 2002. https://cronfa.swan.ac.uk/Record/cronfa42376.
Testo completoAbstract (sommario):
The present research is concerned with health monitoring techniques for rotating machinery, for example Turbogenerator (TG) sets in the power industry. Vibration based condition monitoring is widely accepted for rotating machinery and hence the vibration response of a machine is again utilized in the present research study. Experience shows that faults develop in rotating machines during normal operation and hence their quick identification and remedy are important from safety and plant productivity considerations. The vibration based fault identification procedures are well developed for rotating machinery. However the quantification part of the identified faults has still not matured, and is an ongoing research topic. Hence the remedial action is usually time consuming, even though the machine is known to have some known faults, due to lack of knowledge of their locations and the extent of the faults. In general such a quantification of the identified fault relies on the mathematical model of the complete system along with the measured vibration response of the system. Rotating machinery consists of three major parts - a rotor, fluid journal bearings and a foundation which is often flexible. Often a good model of the rotor (usually a finite element model) and an adequate model of the fluid bearings may be constructed. However, a reliable model for the foundation is difficult to construct due to a number of practical difficulties. Hence the present study has concentrated on two objectives - reliable modelling for the foundation and the quantification of faults using the measured vibration response at the bearing pedestals and the mathematical model of the rotor and the fluid bearings. For the foundation model, the theory which was developed to estimate the models for flexible foundation has been described in the thesis. The method uses measured vibration response at bearing pedestals during machine run-downs, a priori rotor and journal bearing models, and a knowledge of the rotor unbalance, to estimate the stiffness, damping and mass matrices of the foundation. The method was tested on both simulated and experimental examples. The prediction capability of the estimated foundation model was also demonstrated. For the fault estimation a different approach has been used. It has been assumed that the foundation mathematical model is not known, and it is demonstrated that the two faults - the state of rotor unbalance and the misalignment in the rotor can be estimated reliably. The theory of the proposed methods is discussed in the thesis. The method uses measured vibration response at bearing pedestals during a single machine run-down, and a priori rotor and journal bearing models, to estimate the rotor unbalance and the misalignment along with the foundation parameters, so that the dynamics of the foundation is also accounted for during the estimation. The methods were tested on simulated and experimental examples and the estimation accuracy was found to be excellent and generally robust to errors in the rotor and bearing models.
29
Bury, A. S. "Torsional vibration problems in reciprocating machinery." Thesis, Сумський державний університет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/34851.
Testo completoAbstract (sommario):
Torsional vibration can be broadly described as the angular vibration of any object as a result of applied torque. Torsional vibration involves the twisting of shafts while the machinery is rotating.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34851
30
Lau, M. W. S. "Active vibration control at machinery feet." Thesis, Aston University, 2000. http://publications.aston.ac.uk/15340/.
Testo completoAbstract (sommario):
The unmitigated transmission of undesirable vibration can result in problems by way of causing human discomfort, machinery and equipment failure, and affecting the quality of a manufacturing process. When identifiable transmission paths are discernible, vibrations from the source can be isolated from the rest of the system and this prevents or minimises the problems. The approach proposed here for vibration isolation is active force cancellation at points close to the vibration source. It uses force feedback for multiple-input and multiple-output control at the mounting locations. This is particularly attractive for rigid mounting of machine on relative flexible base where machine alignment and motions are to be restricted. The force transfer function matrix is used as a disturbance rejection performance specification for the design of MIMO controllers. For machine soft-mounted via flexible isolators, a model for this matrix has been derived. Under certain conditions, a simple multiplicative uncertainty model is obtained that shows the amount of perturbation a flexible base has on the machine-isolator-rigid base transmissibility matrix. Such a model is very suitable for use with robust control design paradigm. A different model is derived for the machine on hard-mounts without the flexible isolators. With this model, the level of force transmitted from a machine to a final mounting structure using the measurements for the machine running on another mounting structure can be determined. The two mounting structures have dissimilar dynamic characteristics. Experiments have verified the usefulness of the expression. The model compares well with other methods in the literature. The disadvantage lies with the large amount of data that has to be collected. Active force cancellation is demonstrated on an experimental rig using an AC industrial motor hard-mounted onto a relative flexible structure. The force transfer function matrix, determined from measurements, is used to design H and Static Output Feedback controllers. Both types of controllers are stable and robust to modelling errors within the identified frequency range. They reduce the RMS of transmitted force by between 30?80% at all mounting locations for machine running at 1340 rpm. At the rated speed of 1440 rpm only the static gain controller is able to provide 30?55% reduction at all locations. The H controllers on the other hand could only give a small reduction at one mount location. This is due in part to the deficient of the model used in the design. Higher frequency dynamics has been ignored in the model. This can be resolved by the use of a higher order model that can result in a high order controller. A low order static gain controller, with some tuning, performs better. But it lacks the analytical framework for analysis and design.
31
Cheng, Chun-keung. "The machinery import market in China /." [Hong Kong : University of Hong Kong], 1992. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13302140.
Testo completo
32
Määttä, Timo. "Virtual environments in machinery safety analysis /." Espoo [Finland] : VTT Technical Research Centre of Finland, 2003. http://www.vtt.fi/inf/pdf/publications/2003/P516.pdf.
Testo completoAbstract (sommario):
Diss. -- Tampereen teknillinen yliopisto. Thesis (doctoral)--Tampere University of Technology, 2004.<br>Includes bibliographical references (p. 153-170). Myös verkkojulkaisuna. Also available on the World Wide Web.
33
Sokola, Matija. "Vector control of induction machines using improved machine models." Thesis, Liverpool John Moores University, 1998. http://researchonline.ljmu.ac.uk/4899/.
Testo completo
34
Ridgway, Ian Gilbert. "Prototype combine for grain harvesting based on internal pneumatic transfer /." Title page, table of contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09AFM/09afmr5447.pdf.
Testo completo
35
Ponnaluru, Srinivasa Sasdhar. "Empirical analysis of used construction equipment and auction house revenues." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Dissertations/Fall2009/s_ponnaluru_120109.pdf.
Testo completo
36
Ganguli, ABHIJIT. "Chatter reduction through active vibration damping." Doctoral thesis, Universite Libre de Bruxelles, 2005. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210980.
Testo completoAbstract (sommario):
The aim of the thesis is to propose active damping as a potential control strategy for chatter instability in machine tools.<p>The regenerative process theory explains chatter as a closed loop interaction between the structural dynamics and the cutting process. This is considered to be the most dominant reason behind machine tool chatter although other instability causing mechanisms exist.<p>The stability lobe diagram provides a quantitative idea of the limits of stable machining in terms of two physical parameters: the width of contact between tool and the workpiece, called the width of cut and the speed of rotation of the spindle. It is found that the minimum value of the stability limit is proportional to the structural damping ratio for turning operations. This important finding provides the motivation of influencing the structural dynamics by active damping to enhance stability limits of a machining operation.<p>A direct implementation of active damping in an industrial environment may be difficult. So an intermediate step of testing the strategy in a laboratory setup, without conducting real cutting is proposed. Two mechatronic "Hardware in the Loop" simulators for chatter in turning and milling are presented, which simulate regenerative chatter experimentally without conducting real cutting tests. A simple cantilever beam, representing the MDOF dynamics of<p>the machine tool structure constitutes the basic hardware part and the cutting process is simulated in real time on a DSP board. The values of the cutting parameters such as spindle speed and the axial width of cut can be changed on the DSP board and the closed loop interaction between the structure and the cutting process can be led to instability.<p><p>The demonstrators are then used as test beds to investigate the efficiency of active damping, as a potential chatter stabilization strategy. Active damping is easy to implement, robust and does not require a very detailed model of the structure for proper functioning, provided a collocated sensor and actuator configuration is followed. The idea of active damping is currently being implemented in the industry in various metal cutting machines as part of the European Union funded SMARTOOL project (www.smartool.org), intended to propose smart chatter control technologies in machining operations.<br>Doctorat en sciences appliquées<br>info:eu-repo/semantics/nonPublished
37
Chik, Pui Chi Flora. "Targeting the DNA methylation machinery in cancers." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114316.
Testo completoAbstract (sommario):
Cancer cells have aberrant DNA methylation patterns which are characterized by hypomethylation of a large set of promoters and hypermethylation of tumor suppressor genes. The dynamic nature of the epigenome makes it a valuable target for therapeutic interventions. This thesis focuses on understanding the use of various inhibitors towards DNA methylation-related proteins and their respective anti-cancer activities at both global and gene-specific levels. The widely used demethylating agent 5-azacytidine and 5-aza-2'-deoxycytidine (5-azaCdR) are FDA-approved drugs for the treatment of myelodysplastic syndrome. However, these nucleoside analogs which trap the DNA methyltransferases (DNMTs) are non-specific. Studies have shown that 5-azaCdR induced pro-metastatic genes and caused long distance metastasis. This raises serious safety concerns for their clinical use. On the contrary, targeting the DNMTs individually or in combination did not result in dramatic induction of pro-metastatic genes as with 5-azaCdR treatment. In particular, single DNMT1-specific inhibition resulted in maximum growth suppression when compared to inhibition of all three major DNMTs, while not increasing cell invasiveness. DNMT1 has been shown to be important for cancer growth. Our study supports the idea that DNMT1 has a major role in cancer over the other DNMTs and that DNMT1 inhibitors could be effective anti-cancer drugs. 5-azaCdR has nevertheless been proven to be a potent suppressor of cancer growth. We tested the idea of a combinatorial treatment that may minimize its side-effects on cell invasion while maintaining its growth suppressor effects. The methyl-CpG binding protein 2 (MBD2) protein has been shown to demethylate pro-metastatic genes. Its inhibition in concurrent with 5-azaCdR treatment synergistically suppressed cancer growth, while reversed the 5-azaCdR-induced invasion. In order to have a deeper understanding of the impact of the treatments, microarrays studies on the methylome and transcriptome of the treated cells were carried out. Bioinformatics analysis indicated that the combined treatment suppressed gene networks that were involved in cell mobility, while synergistically enhanced gene networks that were involved in cell death. This data indicate that combining 5-azaCdR treatment with MBD2 inhibition results in more potent anti-cancer effects than either treatment alone. In order to explore the currently available drugs that inhibit MBD2, we tested the combination of S-adenosylmethionine (SAM) with 5-azaCdR on the same cancer cell lines. SAM remethylated gene promoters of pro-metastatic genes and repressed 5-azaCdR-induced invasion similarly to MBD2 inhibition. We then investigated the relationship between SAM and MBD2 downregulation and observed hypermethylation on both CpG and non-CpG sites in the MBD2 promoter upon SAM treatment. Interestingly, inhibition of MBD2 using short interference RNA also resulted in hypermethylation of its own promoter. This observation suggested that SAM treatment could directly downregulate MBD2 expression, which is further downregulated through a feedback loop. These results also suggested that SAM treatment could have a direct effect on MBD2 promoter, which in turn affects multiple MBD2 targets that are involved in invasion. Together, the data from this thesis support the idea that targeting the epigenome could be a highly efficacious anti-cancer therapy and that combining drugs that target DNA methylation could increase the potency over individual treatments.<br>Les cellules cancéreuses présentent un profil de méthylation caractérisé par l'hypométhylation d'un grand nombre de promoteurs et l'hyperméthylation de gènes suppresseurs de tumeur. La nature dynamique de l'épigénome en fait une cible de choix pour les interventions thérapeutiques. Cette thèse vise à comprendre l'utilisation de divers inhibiteurs visant des protéines liées à la méthylation de l'ADN et leurs activités anticancéreuses à une échelle génomique globale et au niveau de gènes particuliers. Les agents déméthylants 5-azacytidine et 5-aza-2'-deoxycytidine (5-azaCdR) sont des médicaments pour le traitement du syndrome myélodysplasiqueapprouvés par la FDA. Cependant, ces analogues de nucléosides qui piègent les DNA méthyltransférases (DNMTs) ne sont pas spécifiques. Des études ont montrées que la 5-azaCdR induisait l'expression de gènes pro-métastatiques et l'apparition de métastases. Ceci soulève de sérieuses interrogations quant à leur utilisation en clinique. À l'inverse, le ciblage spécifique des DNMTs ne conduit pas à une induction dramatique des gènes pro-métastatiques. Plus particulièrement, l'inhibition spécifique de DNMT1 résulte en une suppression de la croissance maximale des tumeurs, sans effet sur l'invasion cellulaire, lorsque l'on compare à l'inhibition des trois principales DNMTs. Notre étude supporte l'idée que DNMT1 à un rôle majeur dans le cancer et que le développement d'inhibiteurs de DNMT1 pourraient conduire à des médicaments anti-cancéreux efficaces.Il a néanmoins été montré que la 5-azaCdR était un suppresseur potentiel de la croissance cancéreuse. Nous avons testé l'hypothèse qu'un traitement combiné permettrait de minimiser ses effets secondaires sur l'invasion cellulaire tout en maintenant ses effets suppresseurs de croissance. Il a été montré que la protéine methyl-CpG binding protein 2 (MBD2) participait à la déméthylationde gènes pro-métastatiques. Son inhibition simultanée à un traitement 5-azaCdR abolit de façon synergétique la croissance cancéreuse, tout en inhibant l'invasion induite par la 5-azaCdR. Des analyses du méthylome et du transcriptome ont été réalisées par micropuces à partir de cellules traitées avec un siRNA dirigé contre l'ARNm de MBD2 et la 5-azaCdR afin d'avoir une meilleure compréhension de l'impact de la combinaison des traitements. Les analyses bioinformatiques ont indiqué que le traitement combiné réprimait des réseaux de gènes impliqués dans la mobilité cellulaire tandis que les réseaux de gènes activés étaient impliqués dans la mort cellulaire. Ces données indiquent que le traitement à la 5-azaCdR combiné avec l'inhibition de MBD2 résulte en de plus puissants effets anti-cancéreux que l'un ou l'autre des traitements individuels.Nous avons également testé la combinaison de la S-adenosylmethionine (SAM), un médicament actuellement disponible sur le marché et inhibant l'activité de MBD2, avec la 5-azaCdR sur les lignées cellulaires utilisées précédemment. La SAM, de façon similaire à l'inhibition de MBD2 par un siRNA, permet la méthylation des promoteurs de gènes pro-métastatiques et réprime l'invasion induite par la 5-azaCdR. Nous avons ensuite examiné la relation entre la SAM, la diminution de l'expression de MBD2 et l'hyperméthylation observée à la fois aux sites CpG et non-CpG au niveau du promoteur de MBD2 après traitement avec la SAM. De façon intéressante, l'inhibition de MBD2 par des petits ARN interférant résulte également en une hyperméthylation de son propre promoteur. Cette observation suggère que le traitement avec SAM pourrait directement réduire l'expression de MBD2, qui serait réduite encore plus via une boucle de rétrocontrôle. L'ensemble des données de cette thèse supporte l'idée que le ciblage de l'épigénome pourrait être une thérapie anti-cancéreuse hautement efficace et que la combinaison de médicaments qui ciblent la méthylation de l'ADN pourrait augmenter l'efficacité des traitements individuels.
38
Moorhouse, Andrew Thomas. "Structureborne emission of installed machinery in buildings." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279723.
Testo completo
39
Rushforth, E. J. "Mechatronic design of high-speed packaging machinery." Thesis, Loughborough University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285913.
Testo completo
40
Bentley, Darren. "Intelligent control of complex soil tillage machinery." Thesis, Cranfield University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399714.
Testo completo
41
Cotta, William Joseph. "Machinery diagnostics and characterization through electrical sensing." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100144.
Testo completoAbstract (sommario):
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 149-151).<br>Two methods of non intrusive sensing and their applications for machinery condition monitoring, energy score keeping, and human activity are presented here. The first method uses existing research on Non Intrusive Load Monitoring (NILM) to refine transient detection methods using image classification techniques. Additionally building on the NilmDB framework, a new framework, TransientDB, is proposed which collects and stores information about detected transients for use in machine learning algorithms. Finally the military and civilian applications of NILM developed from multiple field tests are presented. The second method presented determines the health of machinery resilient mounts using vibration and voltage sensing, this method was developed using a multiple lab experiments, and it's utility is demonstrated in field testing on US Navy ships.<br>by William Joseph Cotta.<br>S.M.
42
Dietz, Anthony, Eric Friets, William Finger, Jerry Bieszczad, Matt Miller, and Lawrence Freudinger. "ONLINE DISTRIBUTED VEHICLE AND MACHINERY HEALTH MANAGEMENT." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/605375.
Testo completoAbstract (sommario):
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada<br>Modern aircraft and space vehicles routinely sense and record vast quantities of information relevant
to assessing the vehicles’ health. However, limitations imposed by the bandwidth of telemetry and
network connections prevent real-time transmission of the complete data set to central stations for
analysis. An online health-management system suitable for bandwidth-limited network
environments that enables interrogation of the full data set by ground-based operators is described.
The system uses distributed objects organized in a data processing hierarchy linked by a buffered
data-management subsystem. Reduced health information is routinely transmitted, but dynamic
reports may be requested on demand from any object.
43
He, Bin. "Drainage effect on machinery size and cost." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1202233841.
Testo completo
44
Ahmadi, Farzad. "Magnetic Micro- and Nanostructures for Electrical Machinery." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1544521347564228.
Testo completo
45
Xiong, Huanbao. "Machinery selection and scheduling model for Virginia." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-07102009-040441/.
Testo completo
46
Glascock, Leslie A. "Increasing the conspicuity of agricultural machinery extremities." Connect to resource, 1995. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1202415272.
Testo completo
47
Sloberg, Hanna, and Sara Nilsson. "Internal Marketing Communication : Alpha, a Machinery Business." Thesis, Karlstads universitet, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-73548.
Testo completoAbstract (sommario):
The aim of this study is to investigate the effectiveness of the internal communication, as a dimension of internal marketing, in a global multicultural company. The study was based on a conceptual model that is a miscellany of theoretical concepts of how to create effective internal marketing communication for global organizations. Through the investigation of the company referred to as Alpha, a quantitative study across six countries was conducted to further the knowledge on how to address the needs of internal customers and adjust the internal marketing strategy thereafter. A questionnaire was sent to a random sample, with a response rate of 215 employees that together reflected the total population of 2831. Through the usage of ANOVAs, the findings displayed significant differences of how the employees in all countries perceived the internal communication at Alpha. The study also compared differences within two countries where there was enough data to investigate differences between categories of employees, these results were not significant. In general, it can be said that the results were grouped by the differences of the three European countries against the three non-European countries. Another prominent finding was that China was separated from the other countries, this was also the instance collectively shown for Sweden and Finland as they were often grouped together. The implications are that possible differences in business culture may have affected these results, which further studies need to investigate. The results jointly report that the internal customers are not satisfied with the internal communication. The conclusion is that the needs of the employees at Alpha should be addressed much further, as a part of the company internal marketing communication strategy.
48
Gotin, Nathalie. "Finite Element Model Updating for Rotary Machinery." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/864.
Testo completoAbstract (sommario):
The main approach of this thesis was to develop a mathematical model that represents a rotary machine. Experimental data was used to define a finite element model (FEM). In order to obtain the experimental data, the rotary machine had to be balanced. An impact hammer test made it possible to obtain frequency response functions (FRF). The frequency response functions were curvefitted in order to obtain the mode shapes and natural frequencies.
Mathematical models have been created with ABAQUS and Matlab. For the Matlab Model the assumption has been made that the rotor machine consists of a specific number of beam elements. The FEM matrices have been reduced with the Guyan Reduction Method to coincide with the DOFs of the experiment. Applying the method of the least square to an Error Function made it possible to obtain new values for the stiffness and damping of the bearings (). This made it possible to update the mathematical model. By applying the Model Assumption Criterion the theoretical model and those detected from the experimental measurement could be validated. The correlation for Mode Shapes 1 could be improved from 0.6647 to 0.8186 and for Mode Shape 2 from 0.0209 to 0.4208. Therefore, the created method could be proven to work. Additionally the whole theory has been validated with a very simplified model.
49
Alzuhd, Tahir Hussein Hasan. "Pressure losses associated with slurry flow in horizontal pipelines." Thesis, University of Hertfordshire, 2003. http://hdl.handle.net/2299/14146.
Testo completoAbstract (sommario):
The flow of solid liquid mixtures (slurries) has attracted much attention in research work because of its importance to industry. Prediction of pressure losses associated with slurry flow helps pipe designers select the correct pipe sizes for optimum energy consumption, equipment sizing and reliable operation of the pipeline networks. Many workers developed empirical correlations, but due to the randomness of the problem they seem of limited use in design applications because they do not contain an assessment except by trial and error, which is costly. The existence of more than one particle size poses more complexities to the slurry flow problem but it is in need in practical applications. The aims of this work are justified under the light of the observations on the state of the art in slurry transport. An experimental program is designed to highlight the effects of this problem through a predetermined set of test runs. The variables are grouped to optimise the number of experiments and to remove the effect of dimensions on the prediction method The test rig is built to serve the aims of this exercise and test runs conducted, results grouped and discussed for polyfractional slurries. A mathematical model is developed in the form of an empirical correlation. Statistical tests are employed to verify the goodness of fit. Finally, conclusions and recommendations for further work are listed.
50
Foster, Christopher A. "Intelligent control study of drive-by-wire agricultural vehicles." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 3.19 Mb., 221 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3221073.
Testo completo