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Tanawongsuwan, Rawesak. "Impact of speed variations in gait recognition." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04072004-180217/unrestricted/tanawongsuwan%5Frawesak%5F200312%5Fphd.pdf.
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Bangalore, Krishna-Prasad Lankarani Hamid M. "Protective bollard design for high speed impact energy absorption." Diss., Click here for available full-text of this thesis, 2006. http://library.wichita.edu/digitallibrary/etd/2006/t051.pdf.
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Thesis (M.S.)--Wichita State University, Dept. of Mechanical Engineering.<br>"May 2006." Title from PDF title page (viewed on October 2, 2006). Thesis adviser: Hamid M.Lankarani. Includes bibliographic references (leaves 62-64).
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Dear, J. P. "The fluid mechanics of high-speed liquid/solid impact." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354324.
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Pilgrim, Michael. "The impact of differential friction on curve negotiation speed." Thesis, University of Canterbury. Engineering, 2014. http://hdl.handle.net/10092/10276.
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This thesis considers the impact of differential skid resistance between wheel paths on the speed at
which a vehicle can safely negotiate a curve. Currently the New Zealand Transport Agency undertakes
measurement of the co-efficient of friction on the state highway network by measuring both wheel
paths, but taking the average value to represent the level of skid resistance available. Part of the basis
for this approach is that modern cars have Electronic Stability Control that has historically been
considered to negate the effects of any differential friction.
Aside from straight line braking testing, little research has been done on the impacts of differential
friction on curves. There are however a number of areas of research that can be related to this topic.By PC Crash simulation modeling, this research identifies that there are a number of gaps in our understanding of the relationship between vehicles maneuvering on a curve and the effect of varying skid resistance.
It concludes that taking the average of the two values is not the same as considering them separately and, that as the difference in the co-efficient of friction between the wheel paths increases, the speed at which a vehicle can safely maneuver around a curve decreases. It has also been found that when Electronic Stability Control is used the speed at which the vehicle can safely maneuver around a curve decreases further.
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Amine, Simon. "Equivalent numerical model for honeycomb subjected to high speed impact." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=83848.
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Due to their high specific strength and stiffness, honeycomb sandwich structures are used in impact-resistance applications. Their structural efficiency depends to a great extent on the lightweight core separating the face sheets and providing overall high stiffness. Detailed finite element modeling of the penetration of honeycombs by a projectile can be fairly complex, and computationally expensive as shown in the first part of this study. A computationally efficient axisymmetric equivalent numerical homogeneous model for Aluminum 5052-1119 1/8in - 0.001in hexagonal honeycomb subjected to high speed impacts in the range of 60 m/s to 140 m/s is then developed. An equation-of-state model for porous media is used for the equivalent honeycomb medium. A Taguchi optimization, based on four unknown porous material parameters, is carried out. With the optimal set, the equivalent model can accurately predict perforation velocities for different impact conditions. The methodology for the optimization is explained and can be used for any velocity range. The product of this work is a computationally efficient numerical model that requires less than 8% of the time needed to numerically analyze honeycombs in detail.
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Fontana, Quentin P. V. "Speed and temperature effects in the energy absorption of axially crushed composite tubes." Thesis, University of Cambridge, 1990. https://www.repository.cam.ac.uk/handle/1810/205359.
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Tubes of glass reinforced thermosetting resins have been tested in axial compression between steel platens with one end chamfered to prevent critically high loads causing catastrophic centre failure. By testing in such a manner these tubes crush in a progressive and controlled manner, and are capable of exhibiting high levels of energy absorption, particularly when related to the material mass involved. Polymers are known to display viscoelastic behaviour and polymer composites are similarly sensitive to test speed and temperature. Energy absorption in tube crushing has been shown to be speed and temperature sensitive and the purpose of this project has been to understand the variability of the energy absorption and the associated mechanisms. The main aim has been to show how the two variables interrelate. The materials used have been produced by hot rolling of pre-preg cloth or by resinjection into closed moulds. Reinforcement has consisted of woven glass cloth or random glass mat; matrix materials have been epoxy and polyester resins. Trends to higher values of specific energy absorption with increasing speed have been observed for epoxy matrix tubes, while polyester matrix tubes have shown less certain trends and give lower values of specific energy absorption at high speeds. All the tubes have shown a rapid drop in specific energy absorption with increasing temperature above normal room temperature, with changes in crush mode being very apparent. At temperatures in excess of about 100 degrees C the tubes have failed by centre buckling, the transition temperature from normal crushing to buckling being sensitive to the crush speed. The interrelation between speed and temperature effects has been examined. Three factors that prevent simple interrelation have been identified; these are inertial effects of crush debris, residual stresses in the hoop direction of the tube and frictional heating in the crush zone. Speed sensitivity of the energy absorption has been determined over a range of temperatures and various features of these responses related to the responses of the material properties. Frictional temperature rises have been modelled mathematically and the predictions have been shown to be reasonably consistent with experimental measurements. These temperature rises have been shown to be important in determining the speed sensitive behaviour of the energy absorption levels, particularly for polyester resin matrix tubes tested at high speeds.
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Davies, Peter Nicholas Hugh. "Multiple impact jet apparatus : equipment and high-speed rain damage studies." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293390.
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Gotlib, Ilia. "An Analysis of High-Speed Impact Nailing for Lightweight Automotive Structures." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408718602.
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Ponnu, Devanarayanan Balaji. "Impact of Speed Differences between Lanes on the Empirical Fundamental Relationship." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1534622048454184.
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Khumalo, Siboniso T. "Induction motor variable speed drive performance and impact on energy savings." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/8751.
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Bibliography: p. 132-134.<br>ESKOM, together with Municipalities distribute power at a line-to-line voltage of 400+/-10%. Hence in theory, the user ends up with a voltage of 340 to 440. In urban areas 2% voltage unbalance is considered acceptable, while 3% voltage unbalance is considered acceptable for rural areas. The combined effects of under or overvoltages coupled with "acceptable maximum" voltage unbalance is not understood or documented. This project is a comprehensive study of the effects of voltage unbalance in combination with under or overvoltages on induction machines (1M) variable speed drives. In addition the performance with PWM inverters connected to 1M via long cables is also studied. The project starts by an evaluation of previous work on the subject and related topics. Relevant conclusions are made based on the literature review in Chapter One. The second step of the project was to develop two test beds in the UCT Machine's Laboratory. The test beds are for performance testing of low (up to 15kW) and medium (up to 75kW) power 1M and their VSDs. The test bed losses are determined at 4 different operating points and documented. Several tests such as the blocked rotor and no load tests were undertaken to determine the machine parameters. A PSpice simulation model was developed and tested for the low voltage test bed. The test results compared well to simulation predictions. Furthermore, tests under unbalanced and overvoltage conditions were performed and the results verified with simulations. This proves that the developed PSpice model can reliably simulate the actual test bed for both balanced and unbalanced conditions. Moreover, it can be easily applied to model different size machines and drives. The information required includes: the motor parameters, drive dc-link parameters, modulation ratio (ma) and the switching frequency. The impact of voltage unbalance in drives with long cables between the inverter and motor is examined. A 36m long, 4-core, PVC insulated cable is used on the low voltage test bed for a case study. The model used for the cable is a lumped parameter model. The 1M model is also taken from the literature to include a high frequency branch, to model the reflected voltage wave phenomenon. A basic analysis of energy savings in pumps and fans load associated with the application of variable speed drives is also done. Boiler feed-pumps from Tutuka power station are used as a case study that may be replicated for other applications in utilities or industry. The developed Excel Spreadsheet program to project the value of savings and determine the payback period is compared to an ABB program. The two results agree within an acceptable range. Therefore, the knowledge of the pumping system specifications and the cost of energy in kWh with the Energy Savings Program would enable one to project energy savings.
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Anyang, Ernest Ohene. "The impact of variable speed drives on energy efficient induction motors." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/10028.
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Includes abstract.<br>Includes bibliographical references.<br>In an era when the world is faced with diminishing resources and energy security concerns, the slightest energy savings can prove essential in energy conservation. Induction motors and motorised loads consume an estimated 60% of the total energy required in the South African industry. This figure stands at 40% worldwide. Energy Efficient induction motors have proven to be an effective solution in the quest to reduce energy consumption. In South Africa, there have been efforts to replace the standard motors already in operation with energy efficient motors. The South African Utility, ESKOM, through its energy efficiency motor programme, has been providing incentives to its industrial customers to speed up this process.
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Ross, Lesley Anne. "Does speed of processing training impact driving mobility in older adults? /." Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2009r/ross.pdf.
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Thesis (Ph. D.)--University of Alabama at Birmingham, 2007.<br>Title from PDF of title page (viewed Oct. 13, 2009). Additional advisors: Jerri D. Edwards, David L. Roth, David E. Vance, Virginia G. Wadley. Includes bibliographical references (p. 36-44).
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Waxman, Rachel. "Effects of geometry and phase on material damage response under high-speed impact." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/6078.
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Peridynamics, presented by Silling in 2000 [1], is a reformulation of the elastic theory from differential equations to integral equations, which are more equipped to handle discontinuities, such as crack initiation and propagation. Because of this, peridynamics is an effective tool to address many of the problems relevant to the aerospace and defense industries. For example, airborne sand particles and raindrops cause local damage to aircraft in flight. This damage manifests itself as radial and subsurface lateral cracking, as well as increased surface roughness. All of these damage morphologies may result in undesired degradation of mechanical and optical properties.
This dissertation aims to address the question of how peridynamics (PD) can be used as a tool to help understand impact problems and resultant damage. Three main types of problems will be discussed: (1) modeling of quasi-static nano- and micro-indentation in PD; (2) solid impact experiments and simulations involving glass micro-spheres impacting coated and uncoated advanced ceramics, and sand particles impacting optical glasses; and (3) the implementation of a new, fully three-dimensional hyperelastic material model in state-based PD to simulate nylon bead impact and capture the damage patterns relevant to raindrop impact.
In the first portion, a new method for modeling indentation in PD is presented using the principle of viscous damping and automatic convergence checking. In these simulations, depth-controlled indentation is performed by splitting up the total indentation depth into multiple stages, and applying damping at each stage to ensure the system reaches equilibrium before allowing for failure. PD results show good agreement to experimental data, in terms of crack lengths and force-displacement curves.
In a chapter about solid particle impact, two studies are presented. In the first, glass spheres with diameters ranging from 200 to 700 um impact multi-spectral zinc sulfide (MS-ZnS) with various coating systems. It was found that samples containing the REP coating had better resistance to damage than those without. This resistance was evident in all three damage metrics used: impact pit diameter, radial crack length, and lateral crack size. Simulations were carried out in bond-based PD, with good agreement to experiments regarding damage metrics and rebound velocity.
The second solid particle impact study involved sand particles impacting four different types of optical glasses: BK7, alumino-boro-silicate, fused silica, and Pyrex. First, data from experiments was analyzed, and a multi-variable power law regression was performed to show that sand particle shape plays a significant role in resultant damage. This was confirmed via bond-based PD simulations, with damage quantities agreeing well with experimental values.
Finally, the problem of how to model raindrop impact using nylon beads was examined. Due to the large amounts of elastic strain experienced by the nylon beads during impact experiments, it was determined that a hyperelastic material model could be a good fit. Based on elastic theory and classical continuum mechanics, a new, fully three-dimensional Neo-Hookean material model was implemented in nonordinary state-based peridynamics. This model was verified against results and finite element analysis, with very good agreement. Preliminary simulations including damage show good results, consistent with experiments.
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Rondon, Abraham. "The impact of weather conditions on urban travel speed using ANPR observations." Thesis, KTH, Trafik och logistik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-149461.
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Weather conditions may impact traffic flow in different ways. Both the human decisions regarding the trip (route, mode, time) and the trip itself can significantly vary. Driver’s behavior may be affected by weather resulting in, among others, deterioration of the network ’s travel times and speeds. Therefore to study and analyse travel times under different weather conditions, represents an important instrument to support Intelligent Transport Systems (ITS). With the correct knowledge and information, travellers would be able to plan their trips in a cost-efficient way, while traffic managers could take advantages of these predictions to deploy control strategies (e.g. weather-responsive signal timing plans). In this project Automatic Number Plate Recognition (ANPR) data from summer 2012 to summer 2013 from three different arterial routes in Stockholm city is used in order to analyze travel times, at a link level, under different weather conditions. To determine to what extent weather variables such as rain, snowfall, temperature and visibility impact the speeds in the network, weather data is integrated with traffic data (ANPR) and analyzed through linear regression models. Results show that there is in fact a negative effect on speed but also on speed’s variability. This knowledge can be useful for trip planning and for traffic management under different weather conditions.
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Tesfaye, Adula Ermias. "Impact of parking maneuvers on space mean speed and average travel time." Thesis, KTH, Transportvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-38920.
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Parking maneuver is one among the numerous factors which affect the traffic movement. In this thesis work the impact of parking maneuvers and double parking on the traffic performance of urban street segments is studied. In order to analyze the traffic performance, the impact on the travel time and space mean speed is studied. Two approaches are used for the study; the Micro analysis and Macro analysis. In the Micro analysis the study is not time bounded. The impact of individual vehicles is studied against the event of interest. These events include inbound parking maneuvers, outbound parking maneuvers, double parking and the load/unload activities. On the other hand for the Macro study the events in a five minute interval are studied for eight and a half hour for each site. Each five minute interval is taken as a single data input for the regression analysis. To study the impact on travel time speed trajectory is used and to study the space mean speed regression analysis is used. According to this study the parking maneuvers give rise to a speed reduction of almost 2 Km/hr and double parking 7km/hr. Similarly, the load/unload maneuvers cause a speed reduction of 3Km/hr. Normally two basic tasks are included in this thesis work; data reduction and data analysis. The raw data for this thesis work is a video recording of 8 and half hours for four different spots. Regression analysis and speed trajectory are the main analysis approaches employed for the data analysis. Speed trajectory is used for the Micro analysis and regression analysis is used for the Macro analysis.
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Olufowobi, Oluwaseun Temitope. "The Safety Impact of Raising Speed Limit on Rural Freeways In Ohio." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1597014805133206.
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Kato, Takuya S. M. Massachusetts Institute of Technology. "Impact of Japanese high-speed rail extension on aviation : a case study." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/123234.
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Thesis: S.M. in Transportation, Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2019<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 109-111).<br>Since the 1964 introduction of high-speed rail in Japan, intercity transportation has largely been provided by high-speed rail and aviation. As new lines have been added to the high-speed rail network-further enhancing convenience and shortening travel times- more and more passengers prefer it. On the other hand, aviation has also increased in importance with the increase in airport capacity and the entrance of new, low-cost carriers. One major focus is the Tokyo-Sapporo route, which is one of the busiest domestic flight routes in the world. Intercity transportation in Japan may be about to change, however, since high-speed rail is expected to be extended in 2030 that directly links central Tokyo and Sapporo. To develop an optimal strategy for high-speed rail planning, predicting the effect of the high-speed rail extension is essential.<br>The objective of this thesis is to clarify the effect of high-speed rail extension on air transportation and predict the modal share for the Tokyo-Sapporo route. This thesis consists of two sections. In the first section, the relationship between high-speed rail and air transportation is analyzed through several case studies. The result shows that airlines reacted differently depending on the route, improving operational efficiency by changing aircraft size, flight frequency, and airfares. In the second section, discrete choice models are introduced for predicting the effect of the high-speed rail extension. To analyze the growing effect of low-cost carriers, a nested logit model is used. The results show that in-vehicle travel time is the most significant factor in passengers' mode choice, implying that high-speed rail will increase its modal share by reducing in-vehicle travel time. The modal share for high-speed rail between Tokyo and Sapporo is estimated through the simulation.<br>The results suggest that travel time and cost have different characteristics in terms of elasticity, indicating the importance of travel time in the increase of high-speed rail's modal share. Although accurately predicting the share is difficult due to uncertainty about emerging demand for low-cost carriers and high-speed rail travel times, the modal share of high-speed rail is estimated.<br>by Takuya Kato.<br>S.M. in Transportation<br>S.M.inTransportation Massachusetts Institute of Technology, Department of Civil and Environmental Engineering
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Raddatz, M., and H. J. Schönfeldt. "Ejection and impact angles of saltating particles measured with a high-speed camera." Universität Leipzig, 2010. https://ul.qucosa.de/id/qucosa%3A16374.
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3D and 2D trajectory data of sand grains saltating over a bed are presented from highspeed camera measurements. They were obtained at Zingst peninsula and in laboratory using a wind tunnel. Trajectories, calculated with a Runge-Kutta procedure, using values of the mean wind profile and the air flow were fitted to the measured ones. The trajectory with the lowest RMSE against the measured one was used to estimate the
grain diameter of the saltating grain. Also ejection and impact angle, ejection and impact speed of the grain were determined. The results confirm earlier findings that ejection angles decreases with increasing grain diameter. Ejection angles between 57° and 27° for fine (63-200 μm) and middle (200-630 μm) ejecta and between 38° and
20° for coarse grains (630-2000 μm) were found. The impact angle β increases with increasing grain diameter. Impact angles between 8° and 15° for fine impactors and between 12° and 36° for middle and coarse grains were found. Additionally the ratio between the mean ejection angle α and mean impact angle β, which decrease with
increasing grain diameter (Rice et al., 1995), could be confirmed. The ration between the ejection speed ue and impact speed ui was found nearly the same for all determined grain sizes, but the grains ejected from the bed had an average speed of one order of magnitude less than the impact speed.
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Ouedraogo, Nayabtigungu Hendrix. "The Safety Impact of Raising Trucks' Speed Limit on Rural Freeways in Ohio." University of Dayton / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1576248242725121.
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Rosser, Benjamin Albert. "The impact of thought speed and variability on psychological state and threat perception." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/15318.
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The speed and variability of thought are purportedly common features of specific psychological states, such as anxiety and mania. The present study explored the proposed independent and combinational influence of these variables upon condition-specific symptoms and affective state. A general population sample was recruited online (N = 263). Participants completed a thought speed and variability manipulation task, inducing a combination of fast/slow and varied/repetitive thought. Change in anxiety and mania symptoms was assessed through direct self-reported symptom levels and indirect, processing bias assessment (threat interpretation). Results indicated that both fast and varied thought independently increased self-reported manic symptoms. Affect was significantly less positive and more negative during slow thought. No change in anxiety symptoms or threat interpretation was found between manipulation conditions. Critically, no evidence for the proposed combinational influence of speed and variability was found. Implications for developing understanding of condition-specific mechanisms and avenues for therapeutic intervention are discussed.
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DESHPANDE, NIRANJAN V. "DISPERSANT EFFECTIVENESS ON OIL SPILLS: IMPACT OF ENVIRONMENTAL FACTORS." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1178046001.
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Hendricks, Lorin James. "High-Speed Apparatus and Signal Processing for Accoustic Delamination Detection on Concrete Bridge Decks." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8971.
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Maintenance and repair of deteriorating civil infrastructure are global problems requiring significant attention and resources. Accurate measurements of civil infrastructure enable lower repair and rehabilitation costs if mitigation techniques are deployed at earlier stages of deterioration. This research describes an infrastructure inspection solution to scan concrete bridge decks for internal cracking at high speeds. Internal cracking within bridge decks, known as delamination, is a particularly difficult defect to identify because it is often not detectable through visual inspection. State-of-the practice testing approaches involve the use of slow and subjective manual sounding techniques and costly lane closures. The need for an improved testing approach has led to decades of research investigating the use of acoustic impact-echo testing to detect bridge deck delaminations. The research presented here consists of a study of the acoustic radiation patterns of delamination defects when they are impacted. Acoustic data were collected on an in-service bridge deck and compared to acoustic data collected on defects in decommissioned bridge deck slabs and on simulated delaminations. This study examined cases of ideal and non-ideal delaminations on the in-service bridge deck and identified characteristics of non-ideal delaminations. An apparatus consisting of a high-speed impact-echo platform and recording suite was designed and constructed. Using this towed apparatus, an order-of-magnitude increase in scanning speed was obtained over other reported methods. Significant design effort was employed to achieve synchronization between different sensing devices using networked computer systems. Analysis was also developed to process and automatically classify acoustic responses to determine the presence and location of delaminations. Demonstrated performance against ground truth data obtained on an in-service bridge deck includes an achievement of approximately 90% probability of detection with only a 2% false alarm rate within 0.30 m. Because of the need to classify acoustic data when ground truth may not be obtainable, a new outlier rejection algorithm, which robustly removes outliers for classification on both simulated and field test data, was also developed. These contributions advance state-of-the-art bridge inspection and also lay the groundwork for additional studies of bridge deck deterioration processes. The framework also demonstrates how a tedious, subjective, and manual inspection process can be automated using advanced excitation tools, signal processing, and machine learning.
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Bosquet, Vincent. "Speed : système de prοductiοn d'éléments exοtiques déficients en neutrοns". Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMC212.
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L'installation GANIL/SPIRAL1 produit des faisceaux d'ions radioactifs avec la méthode ISOL. Ce travail de thèse se concentre sur le développement et l'amélioration de plusieurs ECSs (Ensemble Cible Source), dans le but d'augmenter la variété et l'intensité des faisceaux d’ions radioactifs disponibles. La première partie de ce mémoire présente les améliorations apportées à l’ECS FEBIAD, qui présentait des problèmes d'efficacité d'ionisation et de fiabilité. À l’aide d’une série de tests expérimentaux, la source du problème a été identifiée et résolue, ce qui a permis d'obtenir une efficacité d'ionisation de l'Ar+ de 20 % et plus de 60 nouveaux faisceaux d’ions radioactifs disponibles à SPIRAL1. La deuxième et principale partie de ce travail se déroule dans le cadre du projet TULIP. Le premier jalon de ce projet, qui consiste en la production de faisceaux de Rb+ déficients en neutrons à l'aide d'une source d'ionisation de surface, a été réalisé et présenté dans cette thèse. L'objectif final est la production de faisceaux d’ions déficients en neutrons dans la région de 100Sn, ce qui nécessite d'adapter le processus d'ionisation à l'ionisation par impact électronique. Par conséquent, une nouvelle source d'ions a été développée. Une simulation numérique et une modélisation analytique ont été développées pour concevoir la source. Enfin, un prototype à température ambiante a été conçu, construit et testé. Ce prototype a été utilisé pour mesurer l'efficacité d'ionisation et le temps de réponse de l'ECS. Les résultats ont été utilisés pour extrapoler l'efficacité d'ionisation à l’ECS haute température, atteignant 5 % d'efficacité pour l'étain<br>The GANIL/SPIRAL1 facility produces Radioactive Ion Beams (RIB) using the ISOL method. This thesis work focuses on the improvement and development of several Target and Ion Source System (TISS), with the aim of increasing the available RIB variety and intensity. The first part of this memoir presents the improvements made on the FEBIAD TISS, which had poor ionization efficiency and reliability issues. Using a series of experimental tests, the source of the problem has been identified and fixed, resulting in an Ar+ ionization efficiency of 20% and over 60 new RIBs available at SPIRAL1. The second and main part of this work takes place within the frame of the TULIP project. The first milestone of this project – producing neutron-deficient Rb+ RIBs using a surface ionization ion source – has been completed and presented in this thesis. The final goal is the production of neutron-deficient RIBs in the region of 100Sn, which requires adapting the ionization process to electron impact ionization. Consequently, a new ion source has been developed. Simulation and analytical modeling were used to design the source. Finally, a room temperature prototype was designed, built, and tested. This prototype was used to measure ionization efficiency and the time response of the TISS. The results were used to extrapolate the ionization efficiency to the high-temperature TISS, achieving 5% efficiency for tin
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Kingston, Kent J. "The Impact of High-Speed Internet Connectivity at Home on Eighth-Grade Student Achievement." Thesis, University of Nebraska at Omaha, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3558271.
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<p> In the fall of 2008 Westside Community Schools – District 66, in Omaha, Nebraska implemented a one-to-one notebook computer take home model for all eighth-grade students. The purpose of this study was to determine the effect of a required yearlong one-to-one notebook computer program supported by high-speed Internet connectivity at school on (a) English, (b) math, (c) reading, (d) science, and (e) composite score norm-referenced EXPLORE achievement test scores, District's Criterion-Referenced Descriptive Writing Assessment scores, and classroom performance grade point average (GPA) scores for the core subjects (a) English, (b) science, (c) social studies, and (d) cumulative GPA scores of eighth-grade students who do not have high-speed Internet connectivity at home (<i>n</i> = 19) compared to eighth-grade students eligible (<i>n</i> = 19) and not eligible (<i>n</i> = 19) for free and reduced price lunch program participation who do have high-speed Internet connectivity at home. The results of this study support the implementation of a one-to-one notebook computer program as a systematic intervention to improve student achievement. Furthermore, all within group pretest-posttest gains and between group posttest-posttest equipoise demonstrated that the achievement gap between students eligible and students not eligible for free or reduced price lunch participation with or without high-speed Internet connectivity at home had been mitigated through participation in the school-wide one-to-one notebook computer program. While the one-to-one notebook eighth-grade computer program in this study may not be singled out solely for between group posttest equipoise causality, its inclusion as a fundamental academic programmatic component of this middle school's curriculum should be considered as a contributing factor.</p>
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Goel, Ashish. "Dynamic loading of structures by high speed granular media." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/277444.
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This thesis analyses the impact of granular aggregates with structures using experiments and numerical simulations. Original contributions include an insight into multiple factors affecting the loading and damage to the structures, along with study of numerical parameters important for realistic prediction of the interaction between the granular media and structures. It extends the current understanding related to such interactions, with an underlying motivation to guide strategies in order to reduce the structural damage. The response of structures impacted by granular media (sand or soil) is of significant research interest for many applications. One of the applications is for landmine explosions which causes ejection of soil from ground and damage to structures impacted by this ejected soil. Experimentation is done in a laboratory setting where the cylindrical sand slugs are generated at high speed using an impulse provided by a piston. This induces a velocity gradient along the slug, because of which the slug expands during the flight before impacting the target. Deformable as well as rigid flat targets are considered in two orientations relative to the incoming slug: perpendicular (i.e. normal orientation) and inclined at an angle of 45°. The targets are supported by force transducers to capture the loading from the slug. Simulations are performed using a combination of discrete particle and finite element schemes, which enables the analysis of the fully coupled interaction between the flowing granular media and the structure. A contact model involving multiple parameters is used for inter-particle and particle-target contact. Firstly, a numerical analysis is performed to characterise the temporal evolution of slugs and their impact on monolithic beams constrained at the ends. Out of all the parameters used for inter-particle contact definition in discrete particle method, only the contact stiffness is found to effect the velocity gradient in the slug before it impacts the target. Other factor influencing the gradient is the acceleration provided by the piston. A strong dependence of beam deflection on the stand-off distance is observed due to the velocity gradient in the slugs. As the second step, the effect of target surface properties on the transmitted momentum is analysed. Experiments are done by applying coatings of different hardness and roughness on the target surface impacted by sand slugs. For normally oriented targets, the transmitted momentum is observed to be insensitive to the change in surface coating. In contrast, for inclined targets, a significant influence of coatings is observed. Additionally, the momentum transmitted to the inclined targets is always less than that for normal targets. Numerical analysis of this surface effect reveals that assuming the slug particles to be spherical shape in simulations does not capture the particle/target interactions accurately and under-predicts the frictional loading on the target. Following this, a detailed numerical study is done to understand the effect of the shape of particles in the slug. Simple shaped non-spherical particles are constructed by combining spherical sub-particles. With increasing angularity of particles in the slug, the frictional loading on the target is shown to increase. This results in an increase of momentum transmitted to inclined targets. For normally oriented targets however, the particle shape does not affect the overall transmitted momentum, which is a behaviour similar to that observed when studying the effect of target surface properties. In addition, effect of fracture of particles in the slug is analysed by using beam connections between sub-particles that break during the impact with the target. If the fracture results in increasing particle angularity, the transmitted momentum increases, whereas the situation reverses if fracture results on more spherical shaped particles. Lastly, a strategy to reduce the loading on the targets is analysed by using sacrificial coating on the target surface. In experiments, this coating is placed on the rigid target surface using a lubricant at their interface. When impacted by the slug, this coating slides on the target surface, resulting in a reduction of frictional loading on the target. If the friction at the coating/target interface vanishes, the transmitted momentum approaches the theoretical minimum value. Simulations are used to first validate the experimental observations and then to extend the concept of sliding coatings using deformable targets. Both the transmitted momentum and deflections depended on the thickness of the target and coating. When a coating is used, the deflections increase due to reduction in target thickness. It is found that the best strategy to reduce the damage to the target is to use least possible thickness of the coating and minimise the friction at the interface between the coating and the target. The presented work examines many of the factors that affect the loading on the target impacted by granular slugs, in addition to characterising the expansion of slugs before the target impact. The analysed factors include those already known such as target stand-off distance, inclination and unveils others such as target surface properties and granular properties. The numerical analysis discloses important parameters and shows the effect of particle shape, highlighting the shortcomings of widely used spherical particle assumption in the numerical studies. A strategy using a sacrificial coating to reduce damage to the target is also analysed.
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Lnu, Abhishek. "The Impact of Climate Change on Air Quality for Midwest USA." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1291144247.
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Ding, Yonglian. "Quantifying the Impact of Traffic-Related and Driver-Related Factors on Vehicle Fuel Consumption and Emissions." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/33350.
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The transportation sector is the dominant source of U.S. fuel consumption and emissions. Specifically, highway travel accounts for nearly 75 percent of total transportation energy use and slightly more than 33 percent of national emissions of EPA's six Criteria pollutants. Enactment of the Clean Air Act Amendment of 1990 (CAAA) and the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) have changed the ways that most states and local governments deal with transportation problems. Transportation planning is geared to improve air quality as well as mobility. It is required that each transportation activity be analyzed in advance using the most recent mobile emission estimate model to ensure not to violate the Conformity Regulation.<P>
Several types of energy and emission models have been developed to capture the impact of a number of factors on vehicle fuel consumption and emissions. Specifically, the current state-of-practice in emission modeling (i.e. Mobile5 and EMFAC7) uses the average speed as a single explanatory variable. However, up to date there has not been a systematic attempt to quantify the impact of various travel and driver-related factors on vehicle fuel consumption and emissions.<P>
This thesis first systematically quantifies the impact of various travel-related and driver-related factors on vehicle fuel consumption and emissions. The analysis indicates that vehicle fuel consumption and emission rates increase considerably as the number of vehicle stops increases especially at high cruise speed. However, vehicle fuel consumption is more sensitive to the cruise speed level than to vehicle stops. The aggressiveness of a vehicle stop, which represents a vehicle's acceleration and deceleration level, does have an impact on vehicle fuel consumption and emissions. Specifically, the HC and CO emission rates are highly sensitive to the level of acceleration when compared to cruise speed in the range of 0 to 120 km/h. The impact of the deceleration level on all MOEs is relatively small. At high speeds the introduction of vehicle stops that involve extremely mild acceleration levels can actually reduce vehicle emission rates. Consequently, the thesis demonstrated that the use of average speed as a sole explanatory variable is inadequate for estimating vehicle fuel consumption and emissions, and the addition of speed variability as an explanatory variable results in better models.<P>
Second, the thesis identifies a number of critical variables as potential explanatory variables for estimating vehicle fuel consumption and emission rates. These explanatory variables include the average speed, the speed variance, the number of vehicle stops, the acceleration noise associated with positive acceleration and negative acceleration noise, the kinetic energy, and the power exerted. Statistical models are developed using these critical variables. The statistical models predict the vehicle fuel consumption rate and emission rates of HC, CO, and NOx (per unit of distance) within an accuracy of 88%-96% when compared to instantaneous microscopic models (Ahn and Rakha, 1999), and predict emission rates of HC, CO, and NOx within 95 percentile confidence limits of chassis dynamometer tests conducted by EPA.<P>
Comparing with the current state-of-practice, the proposed statistical models provide better estimates for vehicle fuel consumption and emissions because speed variances about the average speed along a trip are considered in these models. On the other hand, the statistical models only require several aggregate trip variables as input while generating reasonable estimates that are consistent with microscopic model estimates. Therefore, these models could be used with transportation planning models for conformity analysis.<br>Master of Science
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Burgos, Daniel, Eric Wong, and Kurt Weibel. "Impact of Automated Dispensing Technology on Medication Safety and Costs at an Inpatient Pharmacy." The University of Arizona, 2014. http://hdl.handle.net/10150/614205.
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Class of 2014 Abstract<br>Specific Aims: To compare two groups of automated dispensing technology and their impact on medication safety and costs at an inpatient pharmacy. Methods: A total of 784 medications were audited for Pyxis refill errors, 352 prior to and 432 post implementation of Boxpicker and the ATP High Speed Tablet Packager. Data were collected by obtaining refill reports for automated dispensing. Every other medication on the refill report was audited for errors in the corresponding location of the automated dispensing cabinet. The rate of reported errors was obtained from a self-reported error program, Patient Safety Net (PSN). Analysis related to costs included automated dispensing cabinet related inventory and costs associated with bulk repackaging. All data associated with costs were obtained from pharmacy financial records. Main Results: There was no significant difference in the Pyxis refill error rate between Pyxis PARx and Boxpicker (0.00284% versus 0.00231%, respectively, p =0.88). The total number of automated dispensing cabinet problems reported through Patient Safety Net transiently increased during and after implementation of new automated technology. Value of pharmacy inventory costs associated with automation was $674,460 prior to and $594,789 post implementation of technology. Bulk repackaging with the ATP High Speed Automatic Tablet Packager resulted in an estimated cost savings of $203,400 annually. Conclusion: Implementation of Boxpicker and ATP High Speed Tablet Packager resulted in no significant change in Pyxis refill error rates, a transient increase in reported automated dispensing cabinet problems, a decrease in inventory costs, and savings associated with bulk repackaging.
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Robb, Jennifer. "Study of impact stress in physical models and human vocal folds from high-speed video." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104494.
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It is generally believed that voice overuse and abuse may eventually lead to a number of voice disorders. The link between mechanical stresses in vocal fold tissue and vocal fold damage, however, has not yet clearly been established. One key factor is often hypothesized to be the contact pressure associated with impact between the vocal folds during voicing. Studies of the contact pressure on the medial surface of the vocal folds are scarce. The objective of the present study was to estimate contact pressure in human subjects using high-speed videoendoscopy. The edge velocity of the vocal folds was estimated from the analysis of consecutive digital images. The edge velocity before and after contact, along with ad hoc approximate values for contact area and vocal fold mass, allowed the contact pressure to be estimated from the impulse momentum form of Newton's second law. The results were verified through comparisons with directly measured values in a silicone model. Investigations were carried out in human subjects to compare the contact pressure from high-speed videoendoscopy with contact pressure measured directly using a miniature probe microphone. The contact pressure values estimated from high-speed video were between 600 Pa and 9200 Pa. The values from the probe microphone were between 250 Pa and 800 Pa. The probe microphone values were significantly lower than those from high-speed video. The discrepancies are believed to be mainly due to interference between the probe and the vocal fold motion. Further work is needed to assess the accuracy of quantitative contact pressure estimations from videoendoscopy.<br>La sur-utilisation et l'abus de la voix peuvent mener à des problèmes qui nécessitent des soins cliniques. Les forces dues à l'impact des cordes vocales durant leurs oscillations sont assumées être très importantes dans la formation et la propagation de lésions. Aucun lien direct n'a encore été établi entre les contraintes mécaniques associées à l'impact entre les cordes vocales et les problèmes pathologiques. Le but de cette étude est l'estimation des contraintes mécaniques dues à l'impact entre les cordes vocales lors de la phonation à l'aide d'une caméra vidéo-endoscopique. La vitesse en bordure des cordes vocales a été estimée à partir d'une analyse d'images. La vitesse des cordes vocales ainsi que des valeurs estimées de la masse et de la surface de contact ont permis de calculer la pression sur la surface. Les résultats ont été vérifiés à l'aide d'une comparaison avec les mesures obtenues à l'aide d'une sonde dans une modèle auto-oscillant en silicone. Une série d'expériences a été effectuée sur des sujets humains. Le mouvement des cordes vocales a été enregistré avec une caméra vidéo-endoscopique pour estimer les contraintes d'impacts. Une sonde a été insérée entre les cordes vocales des sujets humains durant la phonation pour une mesure directe. Les valeurs de contraintes d'impacts estimées par l'analyse des images étaient entre 600 Pa et 9200 Pa. Les valeurs obtenues par mesure directe étaient entre 250 Pa et 800 Pa. Cette sous-estimation est due à l'effet de la sonde sur l'oscillation des cordes vocales. De plus amples vérifications sont nécessaires afin d'évaluer le potentiel de cette méthode à des fins cliniques.
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Botros, Barbara Brenda. "Impact of unsteady flow processes on the performance of a high speed axial flow compressor." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44880.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.<br>Includes bibliographical references (leaves 66-67).<br>This thesis examines the unsteady interactions between blade rows in a high Mach number, highly-loaded compressor stage. Two straight vane/rotor configurations with different axial spacing between vane and rotor are considered. The numerical simulations of the two configurations are used to determine the effect of axial blade row spacing on the level of entropy generation and the flow mechanisms that affect stage performance. The rotor shock waves that impinge on the upstream blade row result in shed vortices that convect downstream through the rotor. At the reduced axial spacing, vortices with larger circulation and entropy are formed. Local entropy generation is assessed using a new numerical technique that allows adequate evaluation of spatial derivatives in high gradient regions, such as shock waves. It is found that the main difference in entropy generation between the two configurations studied is associated with the shed vortices. Entropy production and rotor work input depend on the vortex trajectory within the rotor, which in turn depends on the ratio of time scales: the time for vortex convection between blade rows, and the rotor period (i.e. the time for the rotor to move one rotor pitch), for a fixed geometry and inlet Mach number.<br>by Barbara Brenda Botros.<br>S.M.
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Leong, Jeffrey. "Development of a limit state design methodology for railway track." Thesis, Queensland University of Technology, 2007. https://eprints.qut.edu.au/16565/1/Jeffrey_Leong_Thesis.pdf.
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The research presented in this thesis is aimed at developing a limit state design methodology for railway track for recommendation to Standards Australia's next revision of the 'Permanent way materials: prestressed concrete sleepers' code (AS1085.14, 2003).
There is widespread suspicion that the railway track, particularly concrete sleepers, have untapped reserves of strength that has potential engineering and economic advantages for track owners. Through quantifying the effects of train speed, wheel impact loadings and distribution of vehicle loads, track engineers would be able to design railway track more accurately and hence uncover the reserves of strengths in railway track.
To achieve this improvement a comprehensive set of wheel/rail impact measurements has been collected over a one year period to establish a distribution of track loadings. The wheel/rail impact data collected showed a logarithmically linear distribution which shows that impact forces are randomly occurring events. The linearity of the data also allows for wheel/rail impact forces to be forecasted allowing for a more rational risk based design of the railway track.
To help with an investigation of the influence of changes to train operation on the wheel/rail impact force distributions, development of a new dynamic track computer model capable of simulating the complex interaction between the train and track was completed within this research. The model known as DTRACK (Dynamic analysis of rail TRACK) was benchmarked against other dynamic models and field data to validate its outputs.
The field measurements and DTRACK simulations became the basis for development of a limit state design methodology for railway track (risk based approach) for railway track in place of an allowable limit state (compliance based) approach. This new approach will allow track owners to assess the track capacity based on more realistic loads and is expected to allow an increase in the capacity of existing track infrastructure which will allow railways to be more commercially competitive and viable.
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Leong, Jeffrey. "Development of a limit state design methodology for railway track." Queensland University of Technology, 2007. http://eprints.qut.edu.au/16565/.
Full textAbstract:
The research presented in this thesis is aimed at developing a limit state design methodology for railway track for recommendation to Standards Australia's next revision of the 'Permanent way materials: prestressed concrete sleepers' code (AS1085.14, 2003). There is widespread suspicion that the railway track, particularly concrete sleepers, have untapped reserves of strength that has potential engineering and economic advantages for track owners. Through quantifying the effects of train speed, wheel impact loadings and distribution of vehicle loads, track engineers would be able to design railway track more accurately and hence uncover the reserves of strengths in railway track. To achieve this improvement a comprehensive set of wheel/rail impact measurements has been collected over a one year period to establish a distribution of track loadings. The wheel/rail impact data collected showed a logarithmically linear distribution which shows that impact forces are randomly occurring events. The linearity of the data also allows for wheel/rail impact forces to be forecasted allowing for a more rational risk based design of the railway track. To help with an investigation of the influence of changes to train operation on the wheel/rail impact force distributions, development of a new dynamic track computer model capable of simulating the complex interaction between the train and track was completed within this research. The model known as DTRACK (Dynamic analysis of rail TRACK) was benchmarked against other dynamic models and field data to validate its outputs. The field measurements and DTRACK simulations became the basis for development of a limit state design methodology for railway track (risk based approach) for railway track in place of an allowable limit state (compliance based) approach. This new approach will allow track owners to assess the track capacity based on more realistic loads and is expected to allow an increase in the capacity of existing track infrastructure which will allow railways to be more commercially competitive and viable.
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Nastic, Aleksandra. "Cold Gas Dynamic Spray Impact: Metallic Bonding Pre-Requisites and Experimental Particle In-Flight Temperature Measurements." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42086.
Full textAbstract:
The impact phenomena of high velocity micron-size particles, although commonly considered and described as detrimental in numerous engineering applications, can be used in a beneficial way if properly understood and controlled. The Cold Gas Dynamic Spray (CGDS) process, known as a surface modification, repair and additive manufacturing process, relies on such high velocity impacts. In the process, solid particles are accelerated by a supersonic gas flow to velocities up to 1200 m/s and are simultaneously heated to temperatures lower than their melting point. When propelled under proper velocity and temperature, the particles can bond onto a target surface. This bonding is caused by the resulting interfacial deformation processes occurring at the contact interface. Hence, the process relies heavily on the gas/particle and particle/substrate interactions.
Although numerous experimental and/or numerical studies have been performed to describe the phenomena occurring during particle flight and impact in the CGDS process, numerous phenomena remain poorly understood. First, the effect of substrate surface topographical condition on the particle deformation and ability to successfully adhere, i.e. atomically and/or mechanically, has not been thoroughly investigated such that its influence is not well understood. Another aspect of the process that is generating the largest gap between experimental and numerical studies in the field is the lack of particle in-flight temperature measurements. Obtaining such data has proven to be technically difficult. The challenges stem from the short particle flight time, low particle temperature and small particle size preventing the use of established thermal spray pyrometry equipment. Relatedly, lack of such measurements precludes a proper experimental study of the impact related phenomena at the particle/substrate interface. As a result, the effect of particle size dependent temperature on overall coating properties and atomic bonding relies currently on estimates. Finally, the effect of particle impact characteristics on interfacial phenomena, i.e. grain size and geometry, velocity/temperature, and oxide scale thickness, on adhesion and deformation upon single particle collision has also been scarcely studied for soft particle depositions on hard substrate.
Hence, the current research work aims at studying fundamental aspects of particle/gas heat transfer and particle/substrate impact features in goals to improve the understanding of the CGDS process. Different surface preparation methods will be used to create various surface roughness and topographical features, to provide a clear understanding of the target surface state influence on coating formation and adhesion. Additionally, new equipment relying on novel technology, i.e. high-speed IR camera, will be utilized to obtain particle in-flight temperature readings with sequence recordings. Subsequently, the experimental particle in-flight temperature readings will be used to develop a computational fluid dynamics model in goals to validate currently used Nusselt number correlations and heat transfer equations. The particle size-dependent temperature effect on the particle’s elastic and plastic response to its impact with a targeted surface and its ability to successfully bond and form a coating will be studied experimentally. A thorough CFD numerical work, based on experimental findings, will be included to provide full impact characteristics (velocity, temperature, size and trajectory) of successfully deposited particles. Finally, the numerical results will be utilized in the ensuing study to correlate single particle deformation, adhesion and interfacial features to impact characteristics. A finite element model will be included to investigate the effect of particle size dependent temperature on single particle interfacial pressure, temperature and bonding ability.
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Kownatzki, Maximilian. "The speed of strategic decision-making and the impact of corporate involvement at the SBU-level." [S.l.] : [s.n.], 2002. http://aleph.unisg.ch/hsgscan/hm00064048.pdf.
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Sánchez, Borràs Marta. "Impact of rail infrastructure charging systems implemented in europe on the competitiveness of high speed services." Doctoral thesis, Universitat Politècnica de Catalunya, 2009. http://hdl.handle.net/10803/30725.
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European railways have been immersed since the nineties in a restructuring process aimed at improving the effectiveness, quality and economic efficiency of the provision of railway services, as well as stimulating the growth of railway markets. This reform has involved a separation between infrastructure management and operation and the introduction of rail infrastructure charges to regulate the use, by railway undertakings, of the infrastructure managed by infrastructure managers.
Rail infrastructure charges aim, in essence, at recovering costs. Nevertheless, they can have an influence on the usage of the infrastructure, especially in corridors where competition between modes exists. Therefore, special attention should be paid to their definition and amount to ensure that they do not counteract the important effort that the European Union is making to help finance and build a European high speed network aimed at strengthening railways and redressing modal share imbalances.
In Europe, legislation requires transparent and non discriminatory rail access charges, based on the principles of short run marginal social cost although mark ups are permitted where necessary to meet financial requirements. However, it does not specify how these principles should be implemented.
This dissertation has three main tasks. Firstly, it calculates the amount of rail infrastructure charge for European high speed lines/services based on the marginal cost. Secondly, it characterises the rail infrastructure charging systems applied to European high speed lines/services, in order to detect if mark ups above the marginal cost of wear and tear are being applied to those services and if so, how they are applied. Finally, it quantifies the impacts on traffic volumes and mode split resulting from bringing the current levels of rail infrastructure charges (applied in the European high speed network) to the level of marginal cost of maintenance and renewals and to the optimal Ramsey mark up.
According to the results obtained, current levels of rail infrastructure charges implemented in Europe have a negative impact on the competitiveness of the high speed passenger services that run on the European railway network, particularly in the cases where the rail market share is currently low (below 80-85%). Thus, mark ups would not have been imposed after careful consideration of their consequences on the market position of railway undertakings in the market segment in question.
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Sánchez, Borràs Marta. "Impact of rail infrastructure charging systems implemented in Europe in the competitiveness of high speed services." Hamburg Eurail Press, 2009. http://d-nb.info/1002079888/04.
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Saxman, Tim. "The impact on fuel costs when optimizing speed and weight in a single truck transportation system." Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63970.
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Traditionally, route planning in the transportation sector has only focused on minimizing the total distance driven when transporting goods or people. This is often done using software tools since planning the optimal route is a complex task that is hard to solve by hand. While driving the shortest distance possible is an effort towards lowering fuel costs, which is one of the largest operating costs for truck transportation companies, it is not necessarily the most fuel efficient route. Recently, research has emerged regarding fuel minimizing route planning in order to perform transport operations at the lowest fuel cost possible. One factor contributing to fuel consumption is vehicle speed, since high speed means high wind resistance. Fuel can therefore be conserved by driving at lower speeds. Though lower speeds means longer travelling time, meaning that if the route is disrupted, causing a delay, there is an increased risk that all tasks cannot be performed during the started working day. The purpose of this thesis is to determine how to plan fuel efficient routes in a transportation system prone to disruptions. It was conducted at Scania to further understand how their truck customers can increase profitability in their businesses by planning fuel efficient routes. The truck transportation business is under heavy pressure with low margins. It is therefore valuable to plan fuel efficient routes. The outcome of this thesis is two linear programming models for route planning that take truck capacity, customer demand and time windows for delivery into account. The first model can be used during planning to find a fuel efficient route in order to deliver to all customers to the lowest fuel cost possible. The model gives a route with predetermined average speeds between the customers, as well as arrival time at each customer. When appropriate, the truck is proposed to drive at a slightly decreased speed, to lower wind resistance and thereby fuel consumption. By also taking load weight into account, the route can be planned such that a heavy part of the load is delivered early, reducing the weight carried for the rest of the route. The proposed model accomplishes on average 6.3 % lower fuel cost, compared to the most commonly used route planning model, where the shortest total driving distance is sought. If something would happen that disrupts the route, it might be impossible to deliver all customers before the day ends. To handle those situations, a second model is proposed. Once the transport is delayed, the model will revise the initial route and propose a new route based on a cost of delaying a delivery. The goal is then to deliver as much as possible to the lowest possible cost. The new route will still consist of predetermined average speeds and arrival times. The proposed model is a tool for handling the complex task of recalculating routes once a disruption occurs. In summary, the first model provides support to plan a route that potentially lowers the operational costs for truck transportation companies. If the planned route is disrupted, the second model will revise it and give a new route with new speeds and arrival times. If possible, the revised route will still result in making all deliveries, otherwise the model will postpone the smallest deliveries to the next day. Together, the two models serve as a valuable support for truck transport companies that want to increase their profitability by lowering their operational costs.<br>Traditionellt har ruttplanering inom transportsektorn endast fokuserat på att minimera den totala körsträckan vid transport av gods eller människor. Detta görs ofta med hjälp av mjukvaruverktyg, eftersom optimal ruttplanering är en komplex uppgift som är svår att lösa för hand. Att köra den kortaste totalsträckan är ett sätt att sänka bränslekostnaderna, vilket är en av de största driftskostnaderna för lastbilstransportföretag, men det är inte nödvändigtvis den mest bränsleeffektiva rutten. Den senaste tiden har allt mer forskning bedrivits inom bränsleminimering för att kunna utföra transportuppdrag till lägsta möjliga bränslekostnad. En faktor som bidrar till bränsleförbrukningen är fordonets hastighet, eftersom hög hastighet innebär högt luftmotstånd. Bränsleförbrukningen kan därför minskas genom att köra i lägre hastigheter. Även om lägre hastigheter betyder längre körtid, vilket innebär att om rutten störs och lastbilen blir försenad, finns det en ökad risk att allt inte kan levereras under den påbörjade arbetsdagen. Syftet med detta arbete är att bestämma hur bränsleeffektiva rutter kan planeras i ett transportsystem benäget för störningar. Arbetet genomfördes på Scania för att förstå hur deras lastbilskunder kan öka lönsamheten i sina företag genom att planera bränsleeffektivare rutter. Lastbilstransportbranschen är under hög press med låga marginaler. Det är därför värdefullt för Scanias lastbilskunder att planera bränsleeffektiva rutter. Arbetet resulterade i två ruteplaneringsmodeller som tar hänsyn till lastkapacitet, kundbehov och tidsfönster för leverans. Den första modellen kan användas vid planering för att hitta en bränsleeffektiv rutt så att alla kunder levereras till lägsta möjliga bränslekostnad. Modellen ger en rutt med förbestämda genomsnittshastigheter mellan kunderna, såväl som ankomsttid hos varje kund. När det anses lämpligt föreslås något minskade hastigheter, för att minska luftmotståndet och därigenom bränsleförbrukningen. Genom att även ta hänsyn till vikt, kan rutten planeras så att en tung del av lasten levereras tidigt, vilket minskar den vikt som transporteras på resterande sträckor. Den föreslagna modellen uppnår i genomsnitt 6,3% lägre bränslekostnad jämfört med den vanligaste ruteplaneringsmodellen, som ger den kortaste totala körsträckan. Om något skulle hända som stör rutten kan det vara omöjligt att leverera alla kunder innan dagen slutar. För att hantera dessa situationer föreslås en andra modell. När transporten är försenad planerar modellen om den ursprungliga rutten och föreslår en ny rutt baserat på kostnaden för att skjuta upp en leverans. Målet är då att leverera så mycket som möjligt till lägsta möjliga kostnad. Den nya rutten består fortfarande av förbestämda medelhastigheter och ankomsttider. Genom att använda den föreslagna modellen tillhandahålls ett verktyg för att hantera den komplexa uppgiften att planera om rutten vid en störning. Sammanfattningsvis ger den första modellen stöd för att planera en rutt som potentiellt sänker driftskostnaderna för lastbilstransportföretag. Om den planerade rutten utsätts för en störning, föreslår den andra modellen en ny rutt med nya hastigheter och ankomsttider. Om det är möjligt innebär den nya rutten fortfarande att lastbilen levererar till alla kunder, om inte skjuts de minsta leveranserna upp till nästa dag. Tillsammans är de två modellerna ett värdefullt stöd för lastbilstransportföretag som vill öka lönsamheten genom att sänka sina driftskostnader.
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Canessi, Tomà. "Physical modelling of rock fragmentation upon impact." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Find full textAbstract:
Rockfall represents a significant safety hazard in building, civil and mining environment that can cause serious injuries and fatalities and can damage structures, infrastructure and machinery. It is extremely costly to manage and public authorities need reliable tools to study and design protection structures as the performance of the existing structures are variable. Many studies and experiments have been done, but one aspect would lead to a better comprehension of the subject: the fragmentation of blocks upon impact. Rocks commonly break up upon impact but rockfall prediction models currently available mostly ignore this phenomenon, even though fragmentation changes size, shape and energy of falling blocks and can drastically change the outcome of the design of protective structure. For example, if a large rock breaks upon impact and its mass and energy are divided among fragments, a high level of energy is dissipated and ignoring fragmentation would lead on an overdesign of the protection barrier. Moreover, very fast rock fragments may rupture a rockfall protection. The project aims to overcome this limit, studying and considering fragmentation in rockfall model, allowing assessment of the hazard rising from a shattered rock. The intention is to develop a database of experimental data about fragmentation of blocks upon impact by considering the initial conditions that cause fragmentation, the fragment size and mass distribution, the partition of velocity and energy at impact and what may lead to “bullet effect” or high flying fragment. This project aims to include fragmentation in rockfall prediction causes to facilitate a better and safer mitigation of rockfall hazard. Moreover, a better knowledge will directly translate into economical and societal benefits, such as more cost effective and better user experience.
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Zbasnik, Nathaniel. "The Impact of Invasive Lionfish on the Feeding Performance of Endemic Spotted Scorpionfish." TopSCHOLAR®, 2018. https://digitalcommons.wku.edu/theses/2333.
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Invasive species, such as the red lionfish, Pterois volitans, are damaging many ecosystems around the world by out-competing native species. However, little work has been done to determine if P. volitans have a direct influence on the feeding performance of native species with which they compete. This study examines the feeding performance in terms of suction pressure, kinematic timing, and excursion distances of spotted scorpionfish, Scorpaena plumieri. Through multiple trials it was examined how S. plumieri modulate their kinematic behavior in response to P. volitans and a conspecific. The creation of a smaller buccal cavity and a decrease in time of buccal expansion may allow individuals to create greater sub-ambient pressures to increase their prey-capture success. High-speed cinematography and pressure transducers were used to determine if S. plumieri modulate feeding performance in the presence of either P. volitans or a conspecific. The results of the study suggest that S. plumieri do not create larger subambient pressures or modulate their feeding kinematics in the presence of P. volitans or a conspecific.
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Srinivasan, Shekhar. "A Simulation Perspective on Dimensional Control and Formability in Impact Forming." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275004865.
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Zhang, Lihe. "Impact resistance of high strength fiber reinforced concrete." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/705.
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Concrete structures may be subjected to dynamic loading during their service life. Understanding the dynamic properties of concrete structures is becoming critical because of the increased concern about the dynamic loading of both civilian and military structures, and especially, the recent increase in terrorist attacks on structures. Fiber reinforced concrete (FRC) is known to exhibit superior performance in its post-peak energy absorption capacity, (i.e., toughness) under flexural and tensile loading. However, the behavior of fiber reinforced concrete under compressive impact has not previously been investigated. In the present research, the response of fiber reinforced concrete was investigated over the full strain rate regime, from static loading to high strain rate loading, and finally to impact loading. The compressive toughness of FRC under static loading was studied using an existing Japanese standard (JSCE SF-5). Then, a test method for FRC under compressive impact loading was developed, involving the use of a high speed video camera system to measure the deformation of FRC cylinders under compressive impact.
The strain rate sensitivity of FRC in both flexure and compression was also fully investigated. FRC was found to have higher strengths under impact loading (both flexural and compressive) than under static loading. The compressive toughness under impact loading increased due to the high peak load and the high strain capacity. FRC under flexural impact loading showed a greater strength improvement than under static flexure. FRC displays a much higher Dynamic Improvement Factor (DIF) under flexural impact than under compressive impact. It gave an overall higher performance under impact than under static loading. It also exhibited a higher strain rate sensitivity than plain concrete in both compression and flexure.
Damage analysis, in terms of loss of strain energy, was carried out based on damage mechanics principles. Damage was found to increase with increasing strain rate. A new constitutive model was proposed to account for the relationship between DIF (Comp) and strain rate and the data derived from the model were found to be consistent with the experimental results.
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Lin, Hao Yeh, and 林浩業. "Impact to Ground by High Speed Train." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/90905496125075048040.
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碩士<br>國立臺灣大學<br>工程科學與海洋工程學系<br>91<br>ABSTRACT
Due to the geographical features of Taiwan, the location of Science Parks in Taiwan can not keep the enough distance away from the planned route of high-speed rail. Therefore some vibration sensitive semiconductor factories in South Science Park and Hsinchu Science Park have the distance less than 500m away from the high-speed rail. The micro vibration problem induced by a high-speed train becomes an important issue.
In this thesis, the ground vibration induced by high-speed rail is concentrated on the thin soil area located in north Taiwan. The characteristics of wave propagation and the vibration decay on the ground surface under impact loading are analyzed by finite element method.
The reasonable boundary conditions and the FEM model are examined first, e. g. the half-space of underground is replaced by support of boundary spring instead, the infinite soil and ground domain are modeled by non-reflective boundary condition, and the reasonable element size of FEM is studied.
Secondly, the effects of following parameters on the characteristics of ground vibration are examined: the thickness of surface soil layer, the elastic modulus of soil and rock, and the landform.
Finally, the waves propagations on ground induced by high—speed train passing the viaduct are analyzed.
The conclusions of this study are summarized as below:
1. There is no significant difference in vertical vibration level between different soil thicknesses. On the contrary, the horizontal velocity and acceleration in case of thin surface soil layer are higher thicker soil.
2. For a varied surface soil thickness case, the vertical vibration is enlarged at the location where the surface slope is decreased. On the contrary, the vibration is reduced where the surface is increased. The horizontal vibrations are smaller than the flat surface.
3. In case of uniform thin surface soil layer, the vibration is enlarged at the transition point, when the wave is propagated from lower area to higher area. On the contrary, the vibration is reduced at the transition point, when the wave is propagated from higher to lower area.
Keywords: ground vibration, high-speed rail, viaduct, thin soil, FEM
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Bangalore, Krishna-Prasad. "Protective bollard design for high speed impact energy absorption." Thesis, 2006. http://hdl.handle.net/10057/270.
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As is passenger safety of paramount importance to the manufacturer of passenger vehicles, so is the security of the nation to its government. Recent developments in the usage of heavy vehicles by militant outfits to carry out attack has become the main concern of many governments around the world, hence the existence of some kind of barrier to stop heavy vehicles from entering restricted areas was thought of. This barrier must be able to provide both visibility and security without being much expensive. Existence of a concrete wall will undoubtedly provide security but at the same time visibility of the impending danger to the security personnel is compromised. A wall is usually rigid and costs a lot to repair, alter and replace. More over a wall can serve only the purpose stated above; it cannot be used as dead ends to stop vehicles. Also concrete walls occupy more space and are difficult to transport from place to place. A bollard pole with sufficient energy absorbing capability can be used, both, for the above stated reasons as well as a simple restraint at dead ends of a road to save lives. These are more versatile for the reason that they can be used as stationary or be motorized to serve the purpose. Also these provide pedestrians and cyclists through passage as well as restrict large vehicle from passing through. Three dimensional models of the bollard poles with various cross-sections are made and a study is done using Finite Element softwares such as LS-Dyna 970 to find the maximum energy the bollards can absorb and still be able to function normally. The bollards are made from two different materials and a study is made to see whether the material of the bollard is reason for bollard failure at high impact speeds.<br>Thesis (M.S.)--Wichita State University, Dept. of Mechanical Engineering.<br>"May 2006."
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Lin, Chia-Ching, and 林家慶. "Impact to Rail and Bridge by High Speed Train." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/89531094911995779062.
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Hsu, Lin-Ching, and 許琳青. "Impact Responses of Bridges Traveled by High Speed Trains." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/45419939529074959411.
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Xu, Lin-Qing, and 許琳青. "Impact Responses of Bridges Traveled by High Speed Trains." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/10684339263056790274.
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Fen-Lin, Ching, and 林清芬. "A Study on the Traffic Safety Impact Evaluation of the Speed Reducing Devices-As the Speed Hump." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/waa9x3.
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碩士<br>中央警察大學<br>交通管理研究所<br>88<br>The gradually increasing traffic flow and high vehicle speed have already made a deeply concerned and opposed from the residential district residents in many communities, campus and factory roads with low traffic flow. Although the traffic flow is within the residential district's road standard, the speeding vehicles have threatened the residential district residents' life and property safety. In order to protect the pedestrian, motorcycle rider, biker and keep the road traffic calming and safety, there is a lot of speed hump with a camel's hump, which were set up. And the speed hump's effectiveness has attains the majority's residential district residents' confirm. Owing to be short of the national speed hump's reference and standard, there are no standard to follow at present about the speed hump's installation, the materials, the dimensions, the heights, the transverse and vertical widths, the gradients, the night illumination, the warning signs and the other match up facilities.
As a result, this research is especially thorough to review and confer in connection with the speed hump development's problems, such as speed hump’s techniques, environments, beneficial results, laws and decrees, classifications and specifications. We design the speed hump's experiment concerning the vehicle speed effect, the traffic vibrations and the traffic noise. Then we make the traffic impacts and influences analysis with statistics and multivariate analysis methods according to the experimental data. This research shows that the parabolic curve speed hump is the best design hump than the round and top flat hump. And it is worthy of installation’s speed reducing device in low traffic flow residential district. It also can dispel the traffic dangerous and an automobile chassis collision’s prejudices as a result of the gentle speed hump gradient. Eventually, this research conclude 「the speed hump’s installation reference and standard」to provide the traffic authorities reference resources when reediting「The Installation Regulations」.
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Huang, Yu-Hsin, and 黃榆心. "The Impact of High-speed Rail on Urban Land Teleconnection：The Empirical Study of Taiwan High-speed Rail." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/5dz86d.
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Donaher, Garrett. "Impact of Winter Road Conditions on Highway Speed and Volume." Thesis, 2014. http://hdl.handle.net/10012/8241.
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Several past studies have attempted to quantify the impact of winter weather conditions on highway mobility in terms of traffic volume, speed, and capacity. While consistent in their general findings, these studies have shown considerably different results in terms of effect size and contributing factors. More importantly, most of these studies have not attempted to model the effects of winter maintenance operations on mobility or isolate these effects from those due to snowstorm characteristics, rendering their results and the proposed methods of limited use for estimating the benefits of maintenance activities. This research attempts to address this gap through a statistical analysis of a data set that is unique in terms of spatial and temporal coverage and data completeness. The data set includes both event based and hourly observations of road weather and surface conditions, maintenance operations, traffic volume and speed, as well as several other measures, from 21 highway sections across the province of Ontario.
Event based information is available for six winter seasons (2000 to 2006) at 19 of the sites. For this event based data a matched pair technique was employed to determine the changes in traffic volumes and speeds under matched conditions with and without snow events. A regression analysis was subsequently performed to relate the changes in traffic volume and speed over an event to changes in various contributing factors such as highway type, snow event characteristics and road surface conditions. A case study was conducted to illustrate the application of the developed models for quantifying the mobility impact of road surface condition and the mobility benefit of winter maintenance operations.
Complete hourly records were available for all 21 sites for three winter seasons. This was used to perform the evaluation on an hourly basis. A matching technique is employed to assign hour-by-hour median speeds observed under typical weather and road surface conditions to each hour of a snowstorm event. A regression analysis is subsequently performed to relate changes from average hourly speed to various contributing factors such as highway type, weather conditions and maintenance operations. Effects of maintenance operations are represented by an intermediate variable called road surface condition index (RSI). A case study is conducted to illustrate the application of the developed models for quantifying the mobility impact of winter snowstorms and the mobility benefit of maintenance operations.
The models developed in these analyses confirmed the relationships between weather variables and traffic volume and speed described in the literature. In addition a strong association between road surface condition and traffic volumes and speed was identified.
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Tsao, Da-Fa, and 曹大發. "Numerical Simulation of High Speed Impact on a Sandwich Panel." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/03726846720132151538.
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碩士<br>國立臺灣大學<br>應用力學研究所<br>98<br>Large strains often cause material destructions in industry and applications. In numerical simulations, we have to set up material models suitable for computation problems. This thesis simulated bullet penetration problems by LS-DYNA software with Elastic Plastic Hydro Spall Material Model, Johnson Cook Material Model for metals, Johnson Holmquist Concrete Material Model for concrete, and Johnson Holmquist Ceramics Material Model for ceramic.
Concrete is more complicated than the other materials in penetration simulations due to its inhomogeneous composition, which results in errors and inconsistencies. This thesis validated penetration problems employing four concrete models, namely, Johnson Holmquist Concrete in their original document, WES, Forrestal, and U.S. Army empirical formulae. After verifications, we adapted the modeling parameters to calculate bullet impacts on sandwich composite panels. For 9mm Luger bullets with incident angles, the computing results evidence a pertinent angle about 20within which the bullet could penetrate the panel with larger residual kinetic energy than the normal impact.
To improve the sandwich panel strength, we proposed to add a ceramic layer beneath the front steel. B4C, SiC, AlN, and Al2O3 were tested in this investigation. We found that B4C ceramic is the best among the four ceramics. Subsequently, we studied the effects of thickness of B4C ceramic layer on the impact resistance. Numerical results showed that adding 6mm B4C ceramic layer in between the front steal and inner concrete would efficiently enhance the capability of bullet impacting.