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1
Münnich, Matthias. "Beam Deflection". Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5823.
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In order to fully understand the third order nonlinear optical response of materials under high irradiance excitation it is necessary to study the temporal and polarization dependence of nonlinear refraction and absorption. There are several existing approaches such as Z-scan and pump-probe techniques to determine those responses. As part of this work, these approaches will be briefly outlined before presenting beam deflection, applied from photothermal beam deflection, as an alternative experimental technique to determine the nonlinear refraction with its temporal and polarization dynamics. This technique measures the angle of the probe beam deflected via the index gradient of the material induced by strong excitation beam, to determine both the sign and magnitude of the nonlinear refraction. The temporal and tensor properties of the nonlinear refractive index can be determined by introducing a delay line, and by varying the polarization of the excitation and probe beam, respectively. To demonstrate the practicality of the beam deflection technique, we performed measurements on Fused Silica, Carbon Disulfide and Zinc Oxide. Each of these samples shows quite different nonlinear responses. Amorphous fused silica exhibits nonlinear refraction purely from instantaneous electronic contribution; while Carbon Disulfide shows a much slower response, originating not only from the electronic contribution but also from non-instantaneous nuclear movements (e.g. molecular orientation). These two contributions can be separated by varying the polarization direction of the excitation and probe beam. By introducing lock-in detection technique, a sensitivity of /5500 can be achieved. In Zinc Oxide, a wide-bandgap semiconductor, we measure both nonlinear refraction and two-photon absorption simultaneously. Therefore the beam deflection is a sensitive technique, which can be used to measure the time and polarization dynamics of the nonlinear response of the material.M.S.
Masters
Optics and Photonics
Optics and Photonics
Optics; International
2
Tovi, Shivan. "Deflection of concrete slabs : current performance & design deflection limits". Thesis, University of West London, 2017. https://repository.uwl.ac.uk/id/eprint/3836/.
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Deflection is usually controlled by limiting the span/depth ratio. One aspect of this research is to document the deflection of a concrete slab in a large residential block. The other part of the research is to look at current design limits. Limits on deformation were set many decades ago, when the forms of construction, partitions, finishing, cladding and service were very different from what they are now. Part of that is to review the span-to-depth method of design. Site investigation and testing theory through observation and data collection was the main deductive approach of this research. A quantitative method was used to calculate and determine the deflection on concrete slabs, the research is attempted to identify target companies and projects to participate in the research. The data indicate that the slab has not sagged significantly due to the back propping for 30 days. However, it does seem that the slab was sloping down from the corner by 6 mm diagonally across the 12m bay. A margin of deflection around 2mm occurred especially in the mid-span of the slab 12 x 7 m corner bay. The 2 mm deflection occurred at the beginning of the investigation after back propping reinforced concrete corner bay slab. The back propping applied after 7 days of pouring slab.
3
Robertson, Michael James. "Methods for generating deflection-limiting commands". Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/18965.
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Gould, Martin. "Predictive compensation for deflection in turning". Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56772.
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This thesis deals with the investigation concerning a predictive compensation method which corrects for the error on the diameter caused by the deflection when machining a workpiece on a lathe.The deflection model which was formulated to predict the error on the diameter considers the smaller emerging diameter formed by the depth of cut as the tool tip moves along the workpiece, thus improving the accuracy with which the deflection can be predicted. The model also recognizes the fact that the total deflection undergoes an equilibrium search causing the final deflection to reach a smaller value than that which is obtained when using the methods described in literature. Furthermore, the way in which the workpiece is commonly supported in industrial practice, which is having one end rigidly clamped in a chuck at the spindle while the other end is supported by its center at the tailstock, is included in the deflection analysis.
The compensation method can be applied not only to uniform cylindrical bars but also to general shaped workpieces. However the latter must first be partitioned into segments forming a multidiameter shaft for the deflection analysis. Implementation of this predictive compensation method introduces the possibility of obtaining single pass machining with final pass accuracy.
5
Holst, J. M. F. G. "Large deflection phenomena in cylindrical shells". Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.604195.
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In the past, much research effort has been directed towards the problem of buckling of thin cylindrical shell structures under axial loading. Thus far, however, no wholly satisfactory solutions have been attained. In this thesis a new approach to shell buckling is proposed. It is suggested that a careful examination of a heavily deformed shell structure in the post-buckling regime - and the processes leading up to this state of deformation - may clarify some of the principles involved in its loss of stability. The complex deformation patterns can be reduced to a more elementary description consisting of inextensional and transitional regions. Corresponding features are found in shell inversions; and in this dissertation two relatively simple examples of inversion under a radial load are studied. Experiments investigating the inversion of a cylindrical shell under a radial point load are reported. Some straightforward empirical formulae are obtained that well describe the characteristics of the deformed geometry; and the applied load is established as a function of the deformation. The inversion of a spherical shell under a radial point load is considered as means of examining some of the basic features observed in the experiments performed, whilst eliminating the complexities arising from the lack of symmetry in the cylindrical case. A "simple model" is detailed which clearly highlights the major components of the total strain energy of the deformed surface and their origin. The results from this model are confirmed using a finite-element analysis, which also provides a more comprehensive description of the overall stress state of the shell. The finite-element method is likewise applied to the case of the cylindrical shell as an extension of the experiments. Findings from the latter are employed to confirm the validity of the numerical analysis. A detailed account is given of the distribution of stresses and strains over the deformed surface; and the similarities with the case of the spherical shell are outlined. Finally, an analytical model is established for the case of the cylindrical shell using the empirical formulae. The derivation of a condensed expression for the total strain energy is presented. It is shown that the model represents well the relevant data obtained numerically.
6
Villapando, Alyanna Zsalee. "Membrane deflection in inline drip emitters". Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/123244.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (page 25).
This study explores the behavior of membranes found within inline drip emitters when subjected to a concentrated load. Knowing the response of the membrane can be useful in optimizing future emitter designs for characteristics such as lower activation pressure. Two different types of membranes were studied, one from the Jain Turbo Cascade® emitters, and the other from the Jain Turbo Top® emitters. These membranes were placed in a fixture, and a texture analyzer fitted with a ball-end probe was used to measure the force exerted by the membrane at a given deflection. The results were compared to analytical models of the deflection of a simply-supported or clamped rectangular plate with a point load, and it was found that these models do not accurately describe the measured behavior. A sensitivity analysis of the models show that changes in the value of the membrane thickness have the greatest effect on change in theoretical deflection at a given force.
by Alyanna Zsalee Villapando.
S.B.
S.B. Massachusetts Institute of Technology, Department of Mechanical Engineering
7
Mukhopadhyaya, Utpal Kanti. "Deflection routing in buffered binary hypercube switches". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ32794.pdf.
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Purdie, Craig. "Deflection of light with the equivalence principle". Thesis, University of Canterbury. Physics and Astronomy, 1997. http://hdl.handle.net/10092/7939.
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A thorough treatment of the Strong Equivalence Principle is presented, demonstrating its failure in dealing with non-uniform gravitational fields. In particular, a calculation utilising the equivalence principle is shown to produce an incorrect rate of deflection of light. This calculation is used as a tool to investigate the nature of this deflection, and the meaning of the Strong Equivalence Principle.
Using a generalised metric for outside a static, spherically symmetric gravitational source, it is shown that the failure of the equivalence principle is geometric and not due to any particular choice of metric. When transformed into a displaced rectangular coordinate system, the generalised metric consists of both diagonal and off-diagonal elements. Only the diagonal elements are equivalent to a flat, uniformly accelerating frame. The off-diagonal elements produce non-zero elements in the Riemann Curvature Tensor and are thus attributed to curvature. Therefore, the Strong Equivalence principle is only valid in the weak field limit, where the components of the Riemann curvature tensor vanish. In this case the metric becomes flat, which is the equivalent of a uniform gravitational field.
Using the Schwarzschild metric in displaced rectangular coordinates, the effect of curvature on the rate of deflection of light are determined by tracing the effect of the off-diagonal elements. This calculation shows that only one-third of the deflection rate is due to acceleration in the local inertial frame, with the remaining two-thirds being the result of curvature. Because the rate of deflection is is an infinitesimal quantity defined locally, this shows the effects of curvature are important even for local measurements.
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Paek, Sung Wook. "Asteroid deflection campaign design integrating epistemic uncertainty". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105602.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 241-249).
Planetary defense, or asteroid collision avoidance, has been gaining interest with recent meteor or fly-by events, including the Chelyabinsk meteor that entered the Earth's atmosphere and exploded over Russia in 2013. Past or planned robotic missions to near-Earth asteroids are expected to provide an excellent opportunity to demonstrate asteroid deflection techniques. However, applying a deflection technique to a hazardous asteroid in real-world situations requires extreme care for decision makers due to inherent uncertainty. The forms of uncertainty can be epistemic or aleatoric. Epistemic uncertainty can be reduced by replenishing incomplete information with better observations, whereas stochastic uncertainty cannot be reduced owing to its randomness. Although we cannot reduce stochastic uncertainty itself, we can come up with a plan which is robust to random uncertainty, by reducing epistemic uncertainty. This thesis develops a methodology to design an asteroid deflection campaign that consists of multiple mission stages. The first stage serves as a precursor whose type can achieve different amounts of uncertainty reduction. With this in-situ information obtained by precursors, the follow-up stage may adapt its impactor design. The methodology is implemented in the Asteroid Deflection Integrating Epistemic Uncertainty (ADIEU) framework. The ADIEU framework is demonstrated in deflection campaigns of select near- Earth asteroids. Generation of campaign solutions over a 15-year period, with different confidence requirements, requires up to 125,000 full-factorial runs and 400 optimization runs per asteroid. Results show that campaigns which consider and reduce epistemic uncertainty can both decrease launch mass and increase robustness. However, there are also cases, under extreme conditions, where a single-stage mission turns out to perform best. The performance envelopes of these different approaches are superposed to generate a decision map for use as a visual aid. Finally, this thesis concludes by outlining future work to refine the framework, as well as potential uses of the methodology in terrestrial applications.
by Sung Wook Paek.
Ph. D.
10
Avsar, Veysel. "Essays on Administrative Protection and Trade Deflection". FIU Digital Commons, 2011. http://digitalcommons.fiu.edu/etd/440.
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This dissertation analyzes the trading effects and the politics of antidumping. The first essay empirically examines the influence of partisanship on antidumping. I show that an increase in the leftist orientation of the government makes labor intensive industries less likely to file an antidumping petition. I also demonstrate that the increase in the leftist orientation of the government is associated with an increase in the likelihood of an affirmative antidumping outcome for the petitions of labor intensive industries.
The second essay investigates the effect of past exporting relationships of the firms, whose products are targeted by antidumping duties, on their export flows to alternative markets. My estimations show that facing an antidumping duty on a product leads to a 18% increase in the exports of the firm for that product to the alternative countries where the firms previously exported the same product and a 8% increase to the countries where the firms exported another product. On the contrary, I fail to find a significant effect of antidumping duties on the exports of the particular product to third countries to which the firm did not export before. Further, I show that a firm’s probability to start exporting the duty imposed product in a different destination increases by 8-10% if the firm already exported another product to that destination. However, I find no such evidence for the countries to which the firm did not export before.
The third essay empirically analyzes the effect of potential antidumping claims, resulting from an antidumping investigation in the domestic market, on the quality of exported products to the target countries. My findings suggest that retaliation threats increase the quality of firms’ shipments for the named industries’ products to the target countries by 11%. This effect is also significantly increasing in the share of the exports of the named industries’ products shipped to the target country in the firms’ total exports. Further, I show that this effect is 4 % higher for the exporters serving the developed countries and 3% higher for ones serving the heavy antidumping users.
11
Han, Xiao. "Critical Vertical Deflection of Buried HDPE Pipes". Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1490790838331014.
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Chan, Mau Hing. "Photothermal deflection spectroscopy of novel electronic materials". HKBU Institutional Repository, 1996. http://repository.hkbu.edu.hk/etd_ra/66.
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Ryan, Matthew. "Numerical modelling of a liquid jet in an air crossflow". Thesis, University of Nottingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275299.
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Yamaguchi, Kouhei. "On Asteroid Deflection Techniques Exploiting Space Plasma Environment". 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225600.
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Vaziri, Reza. "Finite deflection dynamic analysis of rigid-plastic beams". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25142.
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An analytical procedure, which retains the influence of finite deflections,
is developed herein for the dynamic behaviour of rectangular shaped rigid-plastic beams. In the general formulation of the problem deformation is assumed to proceed under two distinct mechanisms depending on the extent to which the value of the peak pressure exceeds the static collapse pressure of the beam. These mechanisms are described by kinernatically admissible velocity fields that satisfy the appropriate continuity conditions. The governing equations of motion are derived from a variational
statement consisting of the principle of virtual work and D'Alembert's principle. The conventional parabolic yield surface (which describes the coupling action between axial forces and bending moments at yield) and its associated flow rule are adopted to describe the plastic behaviour of the beam material. The kinematic small but finite deflection analysis, in which the membrane forces and bending moments interact, generally leads to basic equations which are of nonlinear character. These resulting equations
are solved analytically and closed form expressions are developed for the prediction of maximum permanent deformation of the beam. A dynamic membrane analysis is carried out in those cases when the input energy is sufficiently high that the beam undergoes moderately large deformation (i.e. deflections of the order of beam thickness). Finally the dependence of the permanent deflection on the applied pressure and impulse is obtained for a family of rectangular pulses. This relationship is represented by an isoresponse curve in a form convenient for direct engineering use.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
16
Schubak, Robert Brian. "Finite deflection dynamic response of axially restrained beams". Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26326.
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The deformation response of symmetrically supported, axially restrained beams subjected to uniformly distributed pulse loads is studied herein, leading to the development of an analytical procedure to predict the character and magnitude of such response. The procedure is valid for beams of any singly symmetric or doubly symmetric cross-section, and is based upon the assumption that the beam material can be approximated as behaving in a rigid-perfectly plastic manner. The governing equations of motion are derived from variational statements consisting of the principle of virtual work and d'Alembert's principle, and include the effects of finite geometry changes.
From the static analysis of axially restrained beams it is found that the yield curve of a beam section may be replaced by a linear approximation thereof to obtain a good estimate of the beam's load capacity. Incorporating the linear yield curve approximation in a dynamic analysis of an axially restrained beam results in the uncoupling of the response into two distinct phases — an initial small deflection phase in which the beam retains bending resistance and deforms as a mechanism formed by plastic hinges, and a subsequent large deflection phase in which the beam has no bending resistance and deforms as a plastic string. The results of such an analysis for a rectangular beam subjected to a rectangular load pulse compare well with the results of a previous solution which used the true quadratic yield curve.
The linear yield curve approximation further results in linear differential equations of motion, and the response to load pulses of general load-time history may be solved in closed form. Blast-type pulses of varying shape are found to induce significantly different permanent deflections in a beam than a rectangular pulse. On the other hand, the effect of finite rise time of the pulse's load intensity is found to be small if the the rise time is less than about twenty to thirty percent of the pulse duration.
A procedure developed by CK. Youngdahl is used to obtain rough estimates of the permanent deformation response by converting a pulse of triangular shape to an "effective" rectangular pulse. These estimates compare well with results obtained by the complete analysis of a triangular pulse developed herein. The use of Youngdahl's procedure combined with the analysis of a rectangular pulse developed herein can provide a quick, simple solution to the permanent deformation of a dynamically loaded beam which is amenable to hand computation.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
17
Parvini, Mehdi. "Pavement deflection analysis using stochastic finite element method". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0014/NQ42757.pdf.
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Parvini, Mehdi. "Pavement deflection analysis using stochastic finite element method /". *McMaster only, 1997.
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Sweeney, Joseph Woods III, i Edward M. Wu. "Computer aided deflection measurements of an aircraft wing". Thesis, Monterey, California. Naval Postgraduate School, 1987. http://hdl.handle.net/10945/22217.
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Al-Sunna, Raed Akram Saliba. "Deflection behaviour of FRP reinforced concrete flexural members". Thesis, University of Sheffield, 2006. http://etheses.whiterose.ac.uk/3597/.
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The design of fibre reinforced polymer (FRP) reinforced concrete (RC) can often be governed by the serviceability limit state of deflection. Currently, the evaluation of short-term deflection of FRP RC is undertaken using radically different approaches, in both research and codes of practice. This study investigates the short-term deflection behaviour of FRP RC, both experimentally and analytically, and examines the merits of those different approaches. Experimentally, 28 RC beams and slabs with glass, carbon or steel rebars are tested under four-point loading. The main variables considered are the reinforcement ratio, modulus of elasticity and bond. In addition to measuring deflections, closely-spaced strain gauges are used to measure rebar strains between one forced crack at midspan and two naturally-occurring cracks on either side. This setup enables the investigation of rebar strains, tension stiffening and bond between flexural cracks. Furthermore, in connection with concrete strains at the extreme compressive concrete fibre, the flexural load-curvature relationship is evaluated experimentally and used to decompose the total deflection into flexural and shear-induced deflections. Analytically two numerical analysis methods are used to provide further insight into the experimental results. Finite element analysis with smeared modelling of cracks is used to predict and examine the stress-displacement response in detail. Cracked section analysis is used to provide upper-bound deflections and strains. This study also deals with the ACI and Eurocode 2 approaches for prediction of short- term deflection. The deflection prediction and tension stiffening expressions of these codes are evaluated against the experimental results of this and other studies. The main conclusion is that deflection of FRP RC is essentially due to flexural curvatures, and can be reasonably evaluated by the tension stiffening model of Eurocode 2. However, with reinforcement of relatively low axial stiffness, and depending on the reinforcement bond characteristics, shear-induced deformations become significant and may need to be evaluated.
21
Elton, Nicholas John. "Light deflection and polarisation rotation in gravitational fields". Thesis, University College London (University of London), 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445262.
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Jarvis, Rollo. "Current deflection NDE for pipe inspection and monitoring". Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/56865.
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The detection of corrosion on insulated and/or coated pipes in the oil and gas industry remains a challenge. Routine inspection, which is commonly achieved with in-line tools known as "pigs", is not possible where there is any risk of the pig becoming stuck. There are thousands of kilometers of pipe worldwide deemed ''unpiggable'' whose safety must be ensured using Non-Destructive Evaluation (NDE) external to the pipe if potentially catastrophic failure is to be avoided. Many NDE techniques lack sufficient sensitivity due to the coating thickness producing a high standoff distance between the pipe and the sensor and therefore require costly and time-consuming removal of the coating. A method capable of detecting and/or monitoring of defects (e.g. one-third-wall depth corrosion) while leaving the insulation/coating intact would be highly attractive. This thesis documents the development of a technique in which a low-frequency AC current is directly injected into the pipe at distant locations, and perturbations in the magnetic field caused by "current deflection" around defects are measured using solid-state magnetic sensors. Two methods of applying this novel technique were investigated. Firstly, scanning the sensors to measure perturbations in the field and screen for defects, and secondly, permanently installing sensors outside the pipe for Structural Health Monitoring (SHM). A Finite Element (FE) model has been developed and used to investigate the practical challenges that are faced by the technique and how these may be overcome. The sensitivity of the technique for defect detection by external pipe scanning in a practical scenario has then been evaluated using a model-assisted Probability of Detection (POD) framework that combines the measurements of the signal from an undamaged pipe with synthetic damage profiles and contributions from general corrosion and sensor misalignment. The results indicate that good performance is expected for damage detection by scanning above a typical insulation thickness with just a few amps of injected current. A similar framework has then been used to evaluate the sensitivity of the technique as an SHM solution which suggests excellent corrosion detection performance with the permanent installation of inexpensive magnetic sensors. The technique has potential advantages over competing methods in both scanning and monitoring modes and there are many opportunities for future development.
23
Oppenheimer, Or. "Comparing the deflection of different colored glass strips". Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119944.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 18).
Glass is a material that has been used for both practical and artistic purposes starting as early as the 1st century BC, and the stiffness of the glass affects how easy the glass is to work with. A three-point bending test was performed at 582°C (1080°F) for strips of transparent red, clear, black, transparent blue, and white glass. The deflection of the center point of each strip of glass was measured as the temperature was held constant. A proportional relationship of deflection with time was found for the red and white glass and the deflection of the clear, black, and blue glass was characterized by a parabolic relation. It was found that the red glass is the least stiff, followed by black, blue and clear, which have no statistically significant difference in stiffness, and finally the white glass was found to be the most stiff. These were contrary to the glass workers expectations, which was that black would be the least stiff. This will help glass workers know which colors will act similarly, and what to expect of different colors of glass.
by Or Oppenheimer.
S.B.
24
Lee, Woong. "Crack deflection and interface cracks in layered composites". Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627252.
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Said, Eman. "On the deflection of s32003 stainless steel beams". Thesis, Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54918.
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Presented in this work are the results of twelve flexural tests conducted on small-scale coupons to establish the load-deflection behavior of UNS S32003 (ATI 2003®) hot-rolled duplex stainless steel flat plates. All specimens were tested as simply supported beams loaded at the midspan. Test specimens had nominal width and thickness of 1 in. and 0.25 in., respectively. Four different span lengths of 4 in., 6 in., 9 in., and 12 in. were investigated. Analysis of the results showed that the non-linear deflection behavior can be estimated reasonably well by adopting the conventional deflection equation pertaining to an assumed linear elastic material, but after replacing the modulus of elasticity with a secant modulus corresponding to the maximum tension strain resulting from the applied load.
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Keys, Martyn John Selby. "Ethical confidence and education : beyond doubt and deflection". Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/10020744/.
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I begin this thesis in the classroom, and with a depiction of a particular, quite prevalent, approach to moral education. My aims are then as follows: (1) to trace how certain influential positions in philosophy of education bolster such an approach, (2) to critique the picture of ethics and ethical development shared by these positions, and (3) to suggest an alternative conception of the ethical life which promises to offer a richer, more fruitful, approach to moral education. My first aim is met through an examination of the works of Robert Dearden and Michael Hand on teaching controversial issues. From these writers I draw out what I describe as a 'rationalistic' approach; where a particular vision of rationality is (a) called on to provide definite foundations for the ethical life, and where by implication, (b) teachers are encouraged to teach various ethical concerns as 'issues' which are resolved, or potentially resolvable, by 'rational' means. My critique of this approach focuses on the deeper but unacknowledged senses of unease that underpin both its vision of rationality, and the justificatory role reason is supposed to play in ethics and moral education. The challenge considers the idea that its conception of rationality is ethically deflective (e.g. that it can constitute an attempt to avoid dealing directly with ethical doubt and disquietude). I go on to explore whether there might be a non-deflective philosophical engagement with the ethical: an approach which avoids succumbing either to the certainties of 'rationalism' or to the potentially corrosive nature of relativistic doubt. In arguing that such a conception can be found in the philosophy of Ludwig Wittgenstein, I explore the possibilities it presents for moral education. Particular attention is paid to the role that the study of literature might play in deepening certain forms of ethical awareness in the classroom.
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Taylor, Neil Vernon. "An integrated approach to expansion deflection nozzle analysis". Thesis, University of Bristol, 2002. http://hdl.handle.net/1983/f70eca23-8d5d-4ed0-8106-279b8f189747.
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Expansion Deflection (ED) nozzles have long been considered as an alternative to conventional bell and conical designs. The ED nozzle has two primary benefits over such nozzle configurations, being shorter, and with the potential for altitude compensation. However, the difficulties involved with modelling the complex flow interactions within the nozzle type have thus far prevented the creation of a reliable method for its design and analysis. The work presented within this dissertation makes use of a combination of several different approaches to flow solution to provide a more complete analysis than previously achieved. The primary advance is the use of a CFD scheme to analyse the transonic throat region, the results of which are used as input to a Method of Characteristics based algorithm for the solution of the inviscid supersonic flow-field. This method is both efficient, and allows contour optimisation through the calculus of variations. The viscous flow region is treated in a partially or fully empirical manner, depending upon ambient pressure. The results of this analysis reveal several previously unidentified flow-field behaviours and design parameter interactions. Careful selection of the variables used to define the throat region is shown to be of considerable importance, as they effect not just the thrust produced, but also whether a real flow through such a nozzle may' exist. Secondly, the high probability of shock wave formation and interaction with the nozzle wall within length optimised ED nozzles is demonstrated. This has consequences for both the design and analysis of the ED nozzle. Overall, a framework is established which allows the flow behaviour and performance characteristics of the nozzle type to be estimated in greater detail than previously possible. The performance increments demonstrated over conventional bell nozzles include an approximately 25 to 50 percent length reduction for nozzles designed for solely high altitude operation, and a similar reduction in length plus a noticeable increase in low altitude thrust for trans-atmospheric nozzles. However, before application of the ED nozzle concept to a real system becomes possible, several areas of uncertainty must be addressed, and these are highlighted at the end of this dissertation.
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Davis, Andrew Scott. "Temperature Induced Deflection of Yttria Stabilized Zirconia Membranes". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1338369600.
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Borrero-Molina, Armando. "Simulation of all-optical networks with deflection routing". Versailles-St Quentin en Yvelines, 2004. http://www.theses.fr/2004VERS0021.
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Dans ce travail de recherche, nous avons développé un simulateur pour les réseaux tout-optique, qui utilise une stratégie de routage par déflexion. La topologie choisie dans notre modèle est un réseau en grille 2D, principalement en raison de la simplicité pour sa mise en forme et de son approche à une topologie réelle. La taille du réseau modélisé est 10 x 10, en prenant en considération que notre réseau est du type "Core Network". Nous avons prouvé un algorithme distribué qui déflecte le plus petit nombre de paquets dans chaque noeud du réseau. Nous l'avons appelé Algorithme de Déflexion Minimal et nous avons évalué ses performances dans un réseau tout optique. Chaque noeud essaie d'envoyer les paquets à leur route optimale, au plus court chemin à leur destination, le chemin avec le nombre minimum de deflexions. Nous avons développé aussi un autre algorithme de routage par deflection qui essaye de faire, une minimisation globale sur tout le parcours des paquets, et nous l'avons appelé Routage Escalier. Nous avons mis en parallèle notre simulateur et nous avons mis en place un simulateur distribué afin d'obtenir de meilleurs temps d'exécution, pour exécuter des problèmes plus grands. Nous avons aussi développé quelques Contrôles d'Access aux réseaux, dans le but de contrôler le flux d'entrée des paquets au réseau, améliorer les performances du temps de transport et contrôler la charge pour offrire diverses Qualités de ServiceIn this work, we hâve developed an aU-optical networks simulator, that uses a deflection routing method. The chosen topology for our rnodel is a 2D grid network, mainly because of its simplicity of implementation and its approach to a real topology. The size of thé modèle network is 10x10. We hâve considered this size, taking in considération that our network is of thé type "Core Network". We hâve proved a distributed algorithm that deflects thé smaltest number of customers in every node of thé net. We hâve called it Minime Deflection Algorithm and we hâve evaluated its performances in an all-optical network. Every node attempts to send thé packets to theirs optimal routes, to thé shortest hop path to their destination, thé path with thé minimum number of deflections. We hâve also developed another deflection routing algorithm that does a gtobal minimization on thé packets route, and we hâve called it, Scate Routing Algorithm. We hâve paralleled our simulator and we hâve imptemented a distributed simulator in order to obtain better exécution times, with thé intention of decrease thé exécution time and to run bigger problems, this is, to exécute thé simulator with bigger values of thé arrivai rate or bigger simulation times, bigger number of hops. We hâve also developed some Network Access Controls, in order to central thé input networks flow, to central thé load to offer diverse types of Quality of Service and to improve thé time transport performances
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Sanchez, Cuartielles J. P. "Asteroid hazard mitigation : deflection models and mission analysis". Thesis, Connect to e-thesis, 2009. http://theses.gla.ac.uk/888/.
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Thesis (Ph.D.) - University of Glasgow, 2009.Ph.D. thesis submitted to the Department of Aerospace Engineering, Faculty of Engineering, University of Glasgow, 2009. Includes bibliographical references. Print version also available.
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Squires, G. R. G. "Investigation Of Begg 'Mini-Spring' Load-Deflection Characteristics". Thesis, Faculty of Dentistry, 1991. http://hdl.handle.net/2123/5080.
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Jalali, Mashayekhi Mohammad. "Deflection of near earth objects (NEO) using tethers". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119580.
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Potential impact hazard posed by near Earth asteroids, has motivated researchers to find effective asteroid deflection techniques. The feasibility of using space tethers for asteroid deflection is examined in this dissertation. A simplified model of the asteroid-tether-ballast system, consisting of a point mass model for the asteroid and the ballast, and a rigid massless tether, is developed first. Eventually, more realistic assumptions are considered in the model. The equations of motion of the system are obtained using the Lagrangian approach. The feasibility of using tether-ballast attachment to perturb the motion of the asteroid is demonstrated via numerical simulations. This deflection method is more effective if the asteroid has a high eccentricity orbit. The results show that, by cutting the tether at an appropriate time, the deflection achieved can be increased. Due to the nonlinear nature of the system dynamics, the best point to cut the tether is determined using the simulated annealing optimization method. To obtain a more realistic model of the system, the dynamics of a tether connected to an irregular shaped asteroid is examined. It is shown that the finite size of the asteroid influences the tether dynamics, via the offset between the point of tether attachment and the center of mass of the asteroid. It is observed by analyzing the higher order harmonics in the gravitational potential of the asteroid that the effects of the finite size of the asteroid can be well approximated by considering a spherical asteroid, without losing much of the dynamical behavior associated with the real shape of the asteroid. A more realistic model of the asteroid-tether-ballast system, using a finite size asteroid, and a tether with a non-negligible mass, is developed next. The tether deployment stage, which is an essential part of a real tether based asteroid deflection mission, is considered in the model. Simulation results show that, the rotational motion of the asteroid helps to increase the deflection achieved. It is noted that tether-assisted deflection in more efficient for fast-rotating asteroids than slow-rotating asteroids. A comparison between the asteroid deflection using tethers, gravity tractor deflection method and deflection via a direct impact, is conducted. It is observed that, tether-assisted asteroid deflection is preferable to the other two methods, if the asteroid is rotating fast, and has a high eccentricity orbit.Les risques potentiels d'impact que représentent les astéroïdes proches de la Terre, ont motivé les chercheurs à trouver des techniques efficaces pour la déviation des astéroïdes. Dans cette thèse, nous avons examiné la possibilité d'utiliser les câbles spatiaux pour la déviation d'astéroïdes. Dans un premier temps, nous avons développé un modèle simplifié du système astéroïde-câble-contrepoids, constitué d'un modèle de masse ponctuelle pour l'astéroïde et le contrepoids, et d'un câble rigide sans masse. Par la suite, nous avons pris en compte des hypothèses plus réalistes dans le modèle. Les équations de mouvement du système sont obtenues en utilisant la méthode de Lagrange. À l'aide de simulations numériques, nous avons démontré la possibilité d'utiliser l'attache câble-contrepoids pour perturber le mouvement de l'astéroïde. Cette méthode de déviation est plus efficace si l'astéroïde a une orbite avec une haute excentricité. Les résultats montrent que, en coupant l'attache à un moment approprié, la déviation atteinte peut être augmentée. En raison de la nature non linéaire de la dynamique du système, le meilleur point pour couper le câble est déterminé en utilisant la méthode d'optimisation du recuit simulé . Afin d'obtenir un modèle plus réaliste du système, nous avons examiné la dynamique d'un câble relié à un astéroïde de forme irrégulière. Il est montré que la taille finie de l'astéroïde influe sur la dynamique du câble, par le décalage entre le point de fixation du câble. Par l'analyse des harmoniques d'ordre plus élevé dans le potentiel de gravitation de l'astéroïde, nous constatons que les effets de la taille finie de l'astéroïde peuvent être bien approximés en considérant un astéroïde sphérique, sans perdre beaucoup du comportement dynamique associé à la forme réelle de l'astéroïde. Par la suite, nous avons développé un modèle plus réaliste du système astéroïde-câble-contrepoids, en utilisant un astéroïde de taille finie, et un câble avec une masse non négligeable. Dans ce modèle, nous considérons que la phase de déploiement du câble est une partie essentielle d'une véritable mission de déviation d'astéroïdes. Les résultats des simulations montrent que le mouvement rotationel de l'astéroïde permet d'augmenter la déviation atteinte. Nous constatons que la déviation assistée par câble est plus efficace pour les astéroïdes à rotation rapide que pour les astéroïdes à rotation lente. Nous avons effectué une comparaison entre la déviation de l'astéroïde à l'aide de câbles, de la méthode de déviation du tracteur de gravité et via un impact direct. Nous observons que la déviation assistée par câble d'un astéroïde est préférable aux deux autres méthodes, si l'astéroïde tourne rapidement, et s'il a une orbite avec une haute excentricité.
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Feng, Jingbin. "Quasi-Static Deflection Compensation Control of Flexible Manipulator". PDXScholar, 1993. https://pdxscholar.library.pdx.edu/open_access_etds/4759.
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The growing need in industrial applications of high-performance robots has led to designs of lightweight robot arms. However the light-weight robot arm introduces accuracy and vibration problems. The classical robot design and control method based on the rigid body assumption is no longer satisfactory for the light-weight manipulators. The effects of flexibility of light-weight manipulators have been an active research area in recent years. A new approach to correct the quasi-static position and orientation error of the end-effector of a manipulator with flexible links is studied in this project. In this approach, strain gages are used to monitor the elastic reactions of the flexible links due to the weight of the manipulator and the payload in real time, the errors are then compensated on-line by a control algorithm. Although this approach is designed to work for general loading conditions, only the bending deflection in a plane is investigated in detail. It is found that a minimum of two strain gages per link are needed to monitor the deflection of a robot arm subjected to bending. A mathematical model relating the deflections and strains is developed using Castigliano's theorem of least work. The parameters of the governing equations are obtained using the identification method. With the identification method, the geometric details of the robot arms and the carrying load need not be known. The deflections monitored by strain gages are fed back to the kinematic model of the manipulator to find the position and orientation of the end-effector of the manipulator. A control algorithm is developed to compensate the deflections. The inverse kinematics that includes deflections as variables is solved in closed form. If the deflections at target position are known, this inverse kinematics will generate the exact joint command for the flexible manipulator. However the deflections of the robot arms at the target position are unknown ahead of time, the current deflections at each sampling time are used to predict the deflections at target position and the joint command is modified until the required accuracy is obtained. An experiment is set up to verify the mathematical model relating the strains to the deflections. The results of the experiment show good agreement with the model. The compensation control algorithm is first simulated in a computer program. The simulation also shows good convergence. An experimental manipulator with two flexible links is built to prove this approach. The experimental results show that this compensation control improves the position accuracy of the flexible manipulator significantly. The following are the brief advantages of this approach: the deflections can be monitored without measuring the payload directly and without the detailed knowledge of link geometry~ the manipulator calibrates itself with minimum human intervention; the compensation control algorithm can be easily integrated with the existing uncompensated rigid-body algorithm~ it is inexpensive and practical for implementation to manipulators installed in workplaces.
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Andrén, Peter. "Development and results of the Swedish road deflection tester". Licentiate thesis, KTH, Civil and Architectural Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4050.
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A project to construct a high-speed road deflection tester was initiated in the 1991. A mid-sized truck was used as a carrier for the first prototype. The results were promising and it was decided to build a full-size truck system. The new vehicle, based on a Scania R143 ML, was completed in 1997.
The Road Deflection Tester (RDT) is equipped with two arrays of twenty noncontact laser sensors that collects transversal surface profiles at normal traffic speeds. One profile, placed between the wheel axles, constitutes an unloaded case. The other profile, just behind the rear axle of the vehicle, constitutes the loaded case. By subtracting the front cross profile from the corresponding rear one, the "deflection profile" is assessed. The deflection is assumed to vary with the stiffness of the road.
In order to produce a large load on the rear wheels the engine was mounted in the back of the vehicle, slightly behind the rear axle. In testing mode the rear axle force is approximately 112 kN, and the front axle force is about 30 kN. An incremental wheel pulse transducer, two force transducers and two accelerometers, an optical speedometer and a gyroscope are also mounted on the RDT.
The first test programme was carried out in 1998. Due to the careful choice of test sections, data from these sections still produce the best results. A smaller test programme was carried out in 2001, and a larger one in 2002 when the RDT was taken to England and France for demonstration. Promising results, both on an aggregated scale and for individual test sections, have been obtained. The RDT compares favourably with the Falling Weight Deflectometer.
Short histories of road construction and road research give some historical and cultural background to the more recent developments. A more comprehensive history of rolling deflectographs presents all devices found in the literature from the start in the mid-fifties when the California Traveling Deflectograph and Lacroix Deflectograph were constructed, to the latest laser based High-Speed Deflectograph. Many references are given for further reading.
The data acquisition hardware on the RDT system consist of sensors, signal converters, signal processing cards, an industrial computer for data communication, and an ordinary PC for operating the equipment and data storage. The software used to evaluate the data is written entirely in Matlab. Many levels of pre-processing make evaluation relatively fast, and the modularised design makes it easy to implement new evaluation algorithms in a clean and efficient way.
A literature survey on the deformations of solids under static and moving load is presented in Appendix A. The static case started with Boussinesq in 1885, was much developed in the sixties, but since the eighties only a very limited amount of new results have been published. The moving load case, on the other hand, is still an field of active research and development.
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Andrén, Peter. "Development and results of the Swedish road deflection tester /". Stockholm : Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4050.
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Van, Hoosear Christopher A. "Surface classification via unmanned aerial vehicles gripper finger deflection". Thesis, University of the Pacific, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1548752.
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The purpose of this thesis is to ascertain the feasibility of using strain gauges attached to a Unmanned Aerial Vehicle (UAV) gripper to determine, upon impact, the hardness of a landing site. We design and fabricate a four finger gripper that uses a rotary component to convert the rotational motion of a servo to the linear motion of the finger assemblies. We functionally test a gripper prototype made from rapid-prototype material. We conduct three experiments to test the gripper's functionality. The first experiment tests the gripper's ability to grasp, lift, and release a centered payload, and the gripper performed with overall success rates of 91%, 100%, and 87% respectively. The second experiment tests the gripper's ability to self-align, lift and release the payload and the gripper performed with overall success rates of 99%, 100%, and 96% respectively. The third experiment tests the functional durability of the gripper, and it performed without error for 5000 open/close cycles.
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Meunier, Arthur. "Asteroids deflection using state of the art European technologies". Thesis, KTH, Rymd- och plasmafysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160713.
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In public opinion, protection against asteroids impact has always been on the agenda of space engineering. Actually it started from 1994 when Shoemaker Levy stroke Jupiter. This protection works in two steps: detection of threat and deflection. Some space agencies and foundations monitor the sky and set up scenario. Although the sky is nowadays well monitored and mapped, there is no global plan nowadays against this threat. This paper focuses on the deflection step, and aims at forecasting which variables are involved and their consequences on the deflection mission. In fact the result depends on several factors, like the time before hazardous moment, the accuracy of detection tools, the choice of deflection method, but the most unpredictable are human factors. This study shows a strategy and so tries to give some new response parts to the global deflection problem.
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Quist, Stig Nygaard. "MPLS controlled deflection routing for packet switched optical networks". Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273344.
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Jenkins, David Francis Llewellyn. "Photothermal deflection spectroscopy and its application in remote sensing". Thesis, Cranfield University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303791.
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Gallou, Maria. "The assessment of track deflection and rail joint performance". Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/36196.
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Track stiffness is the one of the most critical parameters of the track structure. Its evaluation is important to assess track quality, component performance, localised faults and optimise maintenance periods and activities. Keeping the track stiffness within acceptable range of values is connected with keeping the railway network in a satisfactorily performing condition, allowing thereby upgrade of its capacity (speed, load, intensity). Current railway standards are changing to define loading and stiffness requirements for improved ballasted and ballastless performance under high speed train traffic. In recent years various techniques have been used to measure track deflection which have been also used to validate numerical models to assess various problems within the railway network. Based on recent introduction of the Video Gauge for its application in the civil engineering industry this project provides the proof of effective applicability of this DIC (Digital image correlation) tool for the accurate assessment of track deflection and the calculation of track stiffness through its effective applicability in various track conditions for assessing the stiffness of various track forms including track irregularities where abrupt change in track stiffness occur such as transition zones and rail joints. Attention is given in validation of numerical modelling of the response of insulated rail joints under the passage of wheel load within the goal to improve track performance adjacent to rail joints and contribute to the sponsoring company s product offering. This project shows a means of improving the rail joint behaviour by using external structural reinforcement, and this is presented through numerical modelling validated by laboratory and field measurements. The structural response of insulated rail joints (IRJs) under the wheel vertical load passage is presented to enhance industry understanding of the effect of critical factors of IRJ response for various IRJ types that was served as a parametric FE model template for commercial studies for product optimisation.
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Dueck, B. "Robust optical diffractive technique to read out cantilever deflection". Thesis, University College London (University of London), 2010. http://discovery.ucl.ac.uk/20170/.
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Microcantilevers have now been used successfully for over a decade. New assays are being developed and tested continuously but the technique has not arrived in hospitals and surgeries yet. The main obstacle was that a robust and reliable readout system which does not need intricate alignment before each measurement was not available. Therefore cantilever devices have only been used in university laboratories. The aim of the research presented in this thesis is to provide a diffractive optical readout for cantilever bending that is rapid, robust and easy to use. The diffractive readout discovered during my PhD involves a laser illuminating the entire cantilever and additionally parts of the chip base to which it is attached. The laser light diffracted from the cantilever contains information that allows a distinction to be made between tilting and bending of the cantilever. Additionally, measurements of the absolute tilting and bending can be performed and the time needed for aligning the cantilever chip in the laser beam is reduced to a minimum. This thesis describes the tools used to develop the diffractive readout and presents experimental results. First, a simulation was programmed to predict results and optimise experimental conditions. Second, an experimental setup was built from scratch and a new ow cell designed which was needed for transmission mode experiments. Third, test experiments in air were performed using a transmissive and a reflective diffraction approach. Fourth and finally, the applicability of the diffractive readout was shown by demonstrating that the binding of the antibiotic vancomycin to a glycopeptide could be measured successfully. I hope that the invention presented in this thesis will help to commercialise the cantilever setup and make it attractive for the use in hospital and surgeries speeding up diagnostic steps from days down to a few minutes. This thesis lays the cornerstone of the discovered, patented and tested optical diffractive readout technique for cantilever based biosensors. Optimisation of the experiment, being very important and essential, has to be focused on in the future and is not dealt with in detail in here.
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Kheswa, Bonginkosi Vincent. "Deflection of Ag-atoms in an inhomogeneous magnetic field". Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17891.
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Thesis (MSc)--Stellenbosch University, 2011.ENGLISH ABSTRACT: In the current design of the high temperature gas cooled reactor, a small fraction of coated fuel particles will be defective. Hence, 110Ag may be released from the fuel spheres into the coolant gas (helium) and plate out on the cooler surfaces of the main power system. This poses a radiation risk to operating personnel as well as general public. The objectives of this thesis were to design and construct an apparatus in which silver-109 atoms may be produced and deflected in an inhomogeneous and homogeneous magnetic field, compare experimental and theoretical results, and make a recommendation based on the findings of this thesis to the idea of removing silver-110 atoms from the helium fluid by deflecting them with an inhomogeneous magnetic field onto target plates situated on the inner perimeter of a helium pipe. The experimental results for the deflection of the collimated Ag- atoms with the round-hole collimators showed a deflection of 1.77° and 2.05° of the Ag- atoms due to an inhomogeneous magnetic field when the target plate was positioned 13 and 30 mm away from the magnet, respectively. These values were considerably greater than 0.01° and 0.02° that were calculated for the average velocity of atoms, v = 500 m/s. The case where Ag- atoms were collimated with a pair of slits and the target plate positioned 13mm away from the magnet showed the following: An inhomogeneous magnetic field changes the rectangular shape of the beam to a roughly elliptical shape. The beam of Ag- atoms was not split into two separate beams. This was caused by the beam of Ag- atoms consisting of atoms travelling at different speeds. The maximum deflection of Ag- atoms was 1.16° in the z direction and 1.12° in the x direction. These values were also significantly greater than 0.01 mm calculated at v = 500 m/s. This huge difference between the theoretical and experimental results raised a conclusion that the size of each Ag deposit depended mostly on the exposure time that was given to it. It was noticed that the beam of Ag- atoms was not split into two separate beams, in both cases. The conclusion was that the technique of removing Ag- atoms from the helium stream by means of an inhomogeneous magnetic field may not be effective. This is due to the inability of the inhomogeneous magnetic field to split the beam of Ag- atoms into two separate beams in a vacuum of ~10-5 mbar. It would be even more difficult for an inhomogeneous magnetic field to split the beam of Ag- atoms in helium, due to the Ag- atoms having a shorter mean free path in helium compared to a vacuum.
AFRIKAANSE OPSOMMING: In die huidige ontwerp van die hoë temperatuur gas afgekoelde reaktor, is 'n klein fraksie van omhulde brandstof deeltjies foutief. 110Ag kan dus vrygestel word vanaf die brandstof sfere in die verkoelingsgas (helium) wat dan op die koeler oppervlaktes van die hoofkragstelsel presipiteer. Hierdie 110Ag deeltjies hou 'n bestraling risiko vir die bedryfpersoneel sowel as vir die algemene publiek in. Die doelwitte van hierdie verhandeling is eerstens om 'n apparaat te ontwerp en konstrueer wat silwer-109 atome produseer en nie-homogene en homogene magnetiese velde deflekteer,. Tweedens om die eksperimentele en teoretiese resultate met mekaar te vergelyk. Derdens om 'n aanbeveling te maak gebasseer op die bevindinge van hierdie verhandeling rakende die verwydering van silwer-110 atome uit die helium vloeistof deur hulle met 'n nie-homogene magneetveld te deflekteer op die teikenplate binne-in 'n helium pyp. Die eksperimentele resultate vir die defleksie van die gekollimeerde Ag-atome met die ronde gat kollimators toon ‘n defleksie van 1.77° en 2.05° van die Ag-atome as gevolg van ‘n nie-homogene magneetveld wanneer die teikenplaat 13mm en 30mm, onderskeidelik, vanaf die magneet geposisioneer is. Hierdie waardes is aansienlik groter as die teoretiese defleksies van 0.01° en 0.02o wat bereken is vir ‘n gemiddelde snelheid van 500 m/s vir die atome. Die geval waar Ag-atome met 'n paar splete gekollimeer is en die teikenplaat 13 mm weg van magneet geposisioneer is, is die volgende resultate verkry: 'n nie-homogene magneetveld verander die reghoekige vorm van die bondel na 'n rowwe elliptiese vorm. Die bondel Ag-atome is nie volkome twee afsonderlike bundels verdeel nie. Dit is omdat die bondel van Ag-atome bestaan uit atome wat teen verskillende snelhede beweeg. Die maksimum defleksie van Ag-atome is 1.16° in die z-rigting en 1.12° in die x-rigting. Hierdie waardes is ook aansienlik groter as 0.01° bereken teen 500 m/s. Hierdie groot verskil tussen die teoretiese en eksperimentele resultate dui daarop dat die grootte van elke Ag neerslag grootliks afhanklik is van die blootstellingstyd wat daaraan gegee is. Daar is vasgestel dat die straal van Ag-atome in beide gevalle nie in twee afsonderlike bondels verdeel nie. Die gevolgtrekking is dat die tegniek van die verwydering van Ag-atome uit die helium stroom deur middel van 'n nie-homogene magneetveld nie effektief is nie. Dit is te wyte aan die onvermoë van die nie-homogene magneetveld om die bondel Ag-atome te verdeel in twee afsonderlike bondels in 'n vakuum van ~ 10-5 mbar. Dit sou selfs nog moeiliker vir 'n nie-homogene magnetiese veld wees om die bundel Ag-atome in helium te verdeel, weens die korter gemiddelde beskikbare pad van Ag-atome in helium wanneer dit met 'n vakuum vergelyk word.
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Paul, Matthew G. "Wing Deflection Analysis of 3D Printed Wind Tunnel Models". DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1751.
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This work investigates the feasibility of producing small scale, low aerodynamic loading wind tunnel models, using FDM 3D printing methods, that are both structurally and aerodynamically representative in the wind tunnel. To verify the applicability of this approach, a 2.07% scale model of the NASA CRM was produced, whose wings were manufacturing using a Finite Deposition Modeling 3D printer. Experimental data was compared to numerical simulations to determine percent difference in wake distribution and wingtip deflection for multiple configurations.
Numerical simulation data taken in the form of CFD and FEA was used to validate data taken in the wind tunnel experiments. The experiment utilized a wake rake to measure 3 different spanwise locations of the wing for aerodynamic data, and a videogrammetry method was used to measure the deflection of the wingtips for structural data. Both numerical simulations and experiments were evaluated at Reynolds numbers of 258,000 and 362,000 at 0 degrees angle of attack, and 258,000 at 5 degrees angle of attack.
Results indicate that the wing wake minimum in the wind tunnel test had shifted approximately 8.8mm at the wingtip for the Nylon 910 wing at 258,000 Reynolds number for 0 degrees angle of attack when compared to CFD. Videogrammetry results indicate that the wing deflected 5.9mm, and has an 18.6% difference from observed deflection in FEA. This reveals the potential for small scale wind tunnel models to be more representative of true flight behavior for low loading scenarios.
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Ahmed, Kawa Taha Abualwafa. "Long term deflection of high-performance reinforced concrete beam". Thesis, University of Leeds, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.713470.
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In the design of reinforced concrete structures, a designer must satisfy not only the strength requirements but also the serviceability requirements, and therefore the control of the deformation becomes more significant. To ensure serviceability criterion, it is necessary to accurately predict the cracking and deflection of reinforced concrete structures under load. For accurate determination of the member deflections, cracked members in the reinforced concrete structures need to be identified and their effective flexural rigidities determined. The effect of concrete cracking on the stiffness of a flexural member is largely dependent on both the magnitude and shape of the moment diagram, which is related to the type of applied loading. The aim of the present investigation is to study the cracking behaviour (crack spacing and crack width) of reinforced concrete beam elements constructed from high performance concrete and subjected to bending. An initial optimization was performed to identify a suitable mix design, which has the different required performance attributes of high performance concrete, such as strength, workability, dimensional stability and durability. It is likely that this stage will confirm two mixes, which can be used to compare and contrast the cracking behaviour and to isolate the effect of creep on the long-term performance of such elements constructed from high-strength concrete. Typically, a concrete compressive strength of approximately 100MPa will be sought. High performance concrete is made by partially replacement of cement by silica fume. Once the mixes identified, a series of beams (typically 4.2 m span with a constant moment zone of one and half metres) were tested under 2 point loading (also called 4-point loading including the reactions). These elements were subjected to a constantly applied load for at least three months. The intention was to isolate the effect of creep on the long-term performance of such elements constructed from high-strength concrete. This has not been achieved before. Complimentary tests were also performed on the concrete itself (strength, stiffness, shrinkage, creep (compressive and tensile) etc.). Finally, the deflection, crack width and spacing calculation procedures in several major international concrete codes, including EC2-92 and MC 90, were assessed and some deficiencies in the existing approaches exposed. A comparison between the experimental results, and international codes was presented for all beam specimens time-dependent behaviour. Overall, the programme provided much needed data, which verify the influence of creep and shrinkage on the long-term performance (deflection) of high strength reinforced concrete beam elements.
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Doan, Trung Van. "Long-term Deformations in Prestressed Concrete Box Girder Bridges". Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/12836.
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Long-span prestressed concrete box girder bridges are very sensitive to creep and shrinkage which may induce large deflection effects. Designers tend to rely on the simplified procedures contained in codes of practice for the estimation of service load behaviour. Such procedures usually oversimplify a complex problem and are often unreliable and conceptually misleading. This thesis presents a computer-based step by step numerical modelling procedure incorporating the programming language Matlab5 and the finite element package Strand7. The procedure is used to predict the long-term behaviour of the prestressed concrete box girder bridges built by the balanced cantilever construction over the Nepean River at Pheasants Nest, South of Sydney. Nine of the most common mathematical models for creep and shrinkage are used. The results are compared with survey measurements of the bridges since 1982 to present. It is found that only two prediction models give results which are in close agreement with measured deflections of the bridges. Sensitivity analyses are carried out and the results can be improved by varying model parameters such as concrete strength, humidity and concrete age at first loading. A number of recommendations for future research is presented. A simplified creep and shrinkage analysis procedure is also suggested for use in routine design of prestressed concrete structures.
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Liang, Anthony. "Electric deflection measurements of sodium clusters in a molecular beam". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31750.
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Thesis (Ph.D)--Physics, Georgia Institute of Technology, 2010.Committee Chair: de Heer, Walter; Committee Member: Chou, Mei-Yin; Committee Member: First, Phillip; Committee Member: Whetten, Robert; Committee Member: Zangwill, Andrew. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Carter, Paul M. "A multigrid method for determining the deflection of lithospheric plates". Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27854.
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Various models are currently in existence for determining the deflection of lithospheric plates under an applied transverse load. The most popular models treat lithospheric plates as thin elastic or thin viscoelastic plates. The equations governing the deflection of such plates have been solved successfully in two dimensions using integral transform techniques. Three dimensional models have been solved using Fourier Series expansions assuming a sinusoidal variation for the load and deflection. In the engineering context, the finite element technique has also been employed. The current aim, however, is to develop an efficient solver for the three dimensional elastic and viscoelastic problems using finite difference techniques. A variety of loading functions may therefore be considered with minimum work involved in obtaining a solution for different forcing functions once the main program has been developed. The proposed method would therefore provide a valuable technique for assessing new models for the loading of lithospheric plates as well as a useful educational tool for use in geophysics laboratories.
The multigrid method, which has proved to be a fast, efficient solver for elliptic partial differential equations, is examined as the basis for a solver of both the elastic and viscoelastic problems. The viscoelastic problem, being explicitly time-dependent, is the more challenging of the two and will receive particular attention.
Multigrid proves to be a very effective method applicable to the solution of both the elastic and viscoelastic problems.Science, Faculty of
Mathematics, Department of
Graduate
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Abraham, Jeevan George. "A deflection, buckling and stress investigation into telescopic cantilever beams". Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/7380.
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The telescoping cantilever beam structure is applied in many different engineering sectors to achieve weight/space optimisation for structural integrity. There has been limited theory and analysis in the public domain of the stresses and deflections involved when applying a load to such a structure. This thesis proposes (a) The Tip Reaction Model, which adapts classical mechanics to predict deflection of a two and a three section steel telescoping cantilever beam; (b) An equation to determine the Critical buckling loads for a given configuration of the two section steel telescoping cantilever beam assembly derived from first principles, in particular the energy methods; and finally (c) the derivation of a design optimization methodology, to tackle localised buckling induced by shear, torsion and a combination of both, in the individual, constituent, hollow rectangular beam sections of the telescopic assembly. Bending stress and shear stress is numerically calculated for the same structure whilst subjected to inline and offset loading. An FEA model of the structure is solved to verify the previous deflection, stress and buckling predictions made numerically. Finally an experimental setup is conducted where deflections and stresses are measured whilst a two section assembly is subjected to various loading and boundary conditions. The results between the predicted theory, FEA and experimental setup are compared and discussed. The overall conclusion is that there is good correlation between the three sets of data.
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Broomfield, Susannah Elizabeth. "Large deflection, nonlinear loads analysis, with application to large winglets". Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492476.
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The inclusion of static aeroelastic effects is essential to the accurate calculation of the aerodynamic properties of a wing, the resulting wing loads, and ultimately the mass of the wing. Within an industrial aircraft design cycle, the computational time required for structurally coupled nonlinear flow solvers is impractical for the many different solutions required, even with the current development in computing power. The process currently used by most civilian aircraft manufacturers therefore makes use of time efficient linear panel methods for calculating the aerodynamics and modal data for calculating structural movements.University of Bristol.
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Govender, Evandarin. "An intelligent deflection prediction system for machining of flexible components". Thesis, Nottingham Trent University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367158.
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