Dissertations / Theses: 'Shaped charge'

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Gustafsson, Andreas. "Shaped Charge Design : Construction of a Miniaturized Shaped Charge." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-85465.

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The shaped charges on the market today ranges from about 20 to 200 mm in diameter but there is a need of smaller sizes for example in applications where a small projectile with a high speed is needed or to equip or take out drones with. The objective of this thesis work was to develop a miniaturized shaped charge with dimensions smaller than those available today and preferably with a diameter down to 10 mm. The project was conducted at Karlstad University in collaboration with Saab Dynamics AB. The process used during this project was to start with a feasibility study to obtain information about the limits on dimensions in order to investigate how small dimensions can be used for the casing and liner with respect to manufacturability. The feasibility study was conducted by studying academic literature, contacting companies with expertise within the field of manufacturing. A previously used shaped charge was used as a starting point and the dimensions was scaled in accordance with the objective. The influence of the design parameters was examined using the γSPH module in IMPETUS Afea. The liner material used was restricted to oxygen-free high thermal conductivity copper and different materials for the casing was tested. Two material selections for the casing were made with the aid of Granta Edupack. It has been concluded that it is possible to manufacture a miniaturized shaped charge with dimensions down to about ten mm. Both a design for a jet forming shaped charge and an explosively formed penetrator was developed during the project. The resulting projectile for the explosively formed penetrator had a velocity of 2450 m/s, a total length of 7.3 mm and 3.5 mm in diameter, and the jet forming shaped charge had a jet tip velocity of 7060 m/s and was able to penetrate 38-mm into an AISI 4340 steel target according to the models used in IMPETUS Afea. A prototype was planned but due to cost restrictions, it is left as future work.
Riktad sprängverkan (RSV)-laddningarna som finns på marknaden idag sträcker sig från ungefär 20 till 200 mm i diameter. Det finns dock ett behov för storlekar mindre än detta, till exempel i tillämpningar där en liten projektil med hög fart krävs, alternativt att utrusta eller sänka drönare med. Målet med detta examensarbete var att utveckla en miniatyriserad RSV-laddning med dimensioner mindre än vad som finns tillgängligt idag och helst med en diameter neråt tio mm. Projektet utfördes på Karlstads universitet i samarbete med Saab Dynamics AB. Processen som användes under detta projekt gick ut på att börja med en förstudie for att erhålla information om gränserna för mått för att undersöka hur små dimensioner som kan användas för höljet och linern med avseende på tillverkningsbarhet. Förstudien genomfördes genom att studera akademisk litteratur och kontakta företag med expertis inom tillverkningsområdet. En tidigare använd RSV-laddning användes som startpunkt och dimensionerna justerades i enlighet med målet. Påverkan av parametrar på prestanda undersöktes genom att använda γSPH modulen i IMPETUS Afea. Det använda materialet för linern begränsades till OFHC koppar och olika material för höljet testades. Två materialval gjordes för höljet med hjälp av Granta Edupack. Slutsatsen som kan dras utifrån arbetet är att det är möjligt att tillverka miniatyriserade RSV-laddningar med dimensioner neråt tio mm. Både en design för en strålbildande RSV-laddning och en projektilbildande RSV-laddning utvecklades under projektet. Den resulterande projektilen för den projektilbilande RSV-laddningen hade en fart på 2450 m/s, en längd av totalt 7.3 mm och 3.5 mm i diameter och den strålbildande RSV-laddningen hade en spetsfart på 7060 km/s och kunde penetrera 38 mm AISI 4340 stål enligt modellen som användes i IMPETUS Afea. En prototyp planerades men på grund av kostnadsrestriktioner lämnades det som framtida arbete.

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2

Poole, Chris. "Penetration of a shaped charge." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419435.

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A shaped charge is an explosive device used to penetrate thick targets using a high velocity jet. A typical shaped charge contains explosive material behind a conical hollow. The hollow is lined with a compliant material, such as copper. Extremely high stresses caused by the detonation of the explosive have a focusing effect on the liner, turning it into a long, slender, stretching jet with a tip speed of up to 12km/s. A mathematical model for the penetration of this jet into a solid target is developed with the goal of accurately predicting the resulting crater depth and diameter. The model initially couples fluid dynamics in the jet with elastic-plastic solid mechanics in the target. Far away from the tip, the high aspect ratio is exploited to reduce the dimensionality of the problem by using slender body theory. In doing so, a novel system of partial differential equations for the free-boundaries between fluid, plastic and elastic regions and for the velocity potential of the jet is obtained. In order to gain intuition, the paradigm expansion-contraction of a circular cavity under applied pressure is considered. This yields the interesting possibility of residual stresses and displacements. Using these ideas, a more realistic penetration model is developed. Plastic flow of the target near the tip of the jet is considered, using a squeeze-film analogy. Models for the flow of the jet in the tip are then proposed, based on simple geometric arguments in the slender region. One particular scaling in the tip leads to the consideration of a two-dimensional paradigm model of a ``filling-flow'' impacting on an obstacle, such as a membrane or beam. Finally, metallurgical analysis and hydrocode runs are presented. Unresolved issues are discussed and suggestions for further work are presented.

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Clipii, Tudor. "On mathematical modeling of shaped charge penetration." Thesis, Linköping University, Department of Management and Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11996.

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Shaped charges are a well established type of projectile, subjected to a lot of research ever since emerging as a viable technology in the 1940s. The penetration achieved by shaped charges decreases with increased standoff distance. This is often attributed to the shaped charge jet losing its coherence. The Swedish Defence Research Agency however, noted no such loss of coherence in its experiments. An alternative explanation to the decrease of penetration was instead proposed. The object of this thesis was to investigate this proposed theory. To this end, the hydrocode Autodyn was used, modelling the impact of a high-velocity projectile into a generic target and analysing the resulting behaviour of the target. Several setups were used and several parameters were considered when evaluating the results. The conclusion of this thesis is that the alternative explanation offered is not supported by the observed behaviour of the target in the computer model.

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4

Welsh, B. S. "High speed deformation and break-up of shaped charge jets." Thesis, University of Nottingham, 1993. http://eprints.nottingham.ac.uk/42489/.

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Jets resulting from shaped charges which contain metal liners are able to penetrate hard or armoured targets. Their penetration performance is related to the density of the jet and target material and also the length to which the jet can elongate. Models that describe the processes involved have generally assumed hydrodynamic fluid flow and as such have been very successful in most cases. However, the break-up of jets has proved to be inconsistent with the fluid flow models and cannot be accurately described. Break-up is important since it is the final phenomenon in tensile deformation and therefore represents the limiting extent of jet elongation. Additionally, following break-up the jet fragments are particularly susceptible to lateral velocities and tumbling which dissipate the jets energy and further reduce its penetration performance. Research by Hunting Engineering Limited has indicated that mechanical properties are related to the jet break-up phenomena. However, the deformation and break-up of shaped charge jets is not well understood from a metallurgical point of view. It is essential that the jet is in the solid state for jet break-up phenomena to be related to the mechanical properties of the liner material. This has been demonstrated here by theoretical analysis and more directly by observation of in-flight and captured jet fragments. A series of experiments have been carried out in order to measure and analyse the deformation and attempt to put forward models for the break-up mechanisms in shaped charge jets. These were based upon a series of selected aluminium and aluminium alloys which were processed and heat treated to produce a range of mechanical properties. The properties under consideration are those which describe the materials strength, elongation and work hardening characteristics at intermediate strain rates under laboratory conditions. These have been used to relate metallurgical details to the nature of jet break-up. The better materials for shaped charge jets would appear to be high purity metals which exhibit large ductility through to fracture.

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5

Gurel, Eser. "Modeling And Simulation Of Shaped Charges." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610830/index.pdf.

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Shaped charges are explosive devices with a high penetration capability and are used for both civilian and military purposes. In civilian applications shaped charge devices are used in demolition works, oil drilling and mining. In the military applications, shaped charges are used against different kinds of armors, primarily as anti-tank devices. This thesis work involves the modeling and simulation of shaped charge devices, with the focus being on anti-tank warhead design. Both numerical simulation and analytical calculation methods are used to predict shaped charge performance
in the aspects of jet formation, breakup and penetration. The results are compared within themselves and with the data available in the literature. AUTODYN software is used for the numerical simulations. Different solver and modeling alternatives of AUTODYN are evaluated for jet formation and penetration problems. AUTODYN&rsquo
s Euler solver is used to understand how the jet formation is affected by the mesh size and shape and the presence of air as the surrounding medium. Jetting option in the AUTODYN-Euler simulations are used to simulate jet formation as an alternative to simulations performed using AUTODYN&rsquo
s Euler solver. In the jetting option liner elements are modeled as Lagrangian shell elements, rather than Eulerian elements. Analytical codes are written to study the jet formation, breakup and penetration processes. Many alternative formulas that can be used in the analytical calculations are listed and discussed. Parameters of these formulas are varied to investigate their effects on the results. Necessary constants for the analytical formulas are obtained using the results of AUTODYN simulations.

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Abdelrahman, Hussain Alwany. "The use of polymer bonded explosives improved linear shaped charge designs." Thesis, Cranfield University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357744.

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Leung, Anthony Yat-Wah. "Molecular dynamics study of shaped charge penetration and crystal structure properties." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610707.

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Elshenawy, Tamer Abdelazim. "Criteria of design improvement of shaped charges used as oil well perforators." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/criteria-of-design-improvement-of-shaped-charges-used-as-oil-well-perforators(d627c23e-a05b-42a2-86c3-6d67dfd7b7a7).html.

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In addition to its various military applications, shaped charges have been used in oil industry as an oil well perforator (OWP) to connect oil and gas to their reservoirs. The collapse of the liner material under the explosive load produces a hypervelocity jet capable of achieving a deep penetration tunnel into the rock formation. The achieved penetration depends on the OWP design, which includes the geometry and the material of the explosive and the liner as well as the initiation mode and the casing of the shaped charge. The main purpose of this research is to assess the performance of OWP with different design aspects in terms of its penetration depth into concrete material.This research employed the Autodyn finite difference code to model the behaviour of OWPs in the stages of liner collapse, jet formation and jet penetration. The design parameters of OWPs were studied quantitatively to identify the effect of each individual parameter on the jet characteristics and the jet penetration depth into concrete material according to the API-RP43 standard test configuration. In order to validate the Autodyn jetting analysis, this research compared the jetting simulation results of copper OWP liners with those obtained from flash x-ray measurements while the numerical jet penetration into the laminated concrete target was validated experimentally by the static firing of OWPs. Above-mentioned experiments were designed and performed in this project.The validated hydrocode was implemented in this research to study the effects of the concrete target strength, the liner material and the liner shape on the jet penetration depth into concrete targets.For the target strength, the traditional virtual origin (VO) penetration model was modified to include a strength reduction term based on Johnson’s damage number and the effect of the underground confinement pressure using Drucker-Prager model. The VO analytical model is also implemented in the liner material study to account for the jet density reduction phenomena and its induced reduction of jet penetration capability. The jets obtained from machined copper and zirconium liners and from copper-tungsten powder liner all exhibited the density reduction phenomena. The modified VO model considers the non-uniform distribution of jet density based on the jet profile analysis using Autodyn and the experimental soft recovery for some tested liners. The results lead to a modified VO penetration model including the non-uniform jet density effect.For zirconium liner material, numerical and analytical studies were conducted for different flow velocities and different collapse angles in order to determine the boundaries between the jetting and non-jetting phases and whether a coherent or a non-coherent jet will form. This study indicated that the suggested four different liner shapes (i.e. the conical, the biconical, the hemispherical and the bell) will produce coherent jet when the zirconium is used as OWP liner.The validated Autodyn hydrocode is also used in this thesis to calculate the velocity difference between two neighbouring zirconium jet fragments. The velocity difference is related directly to the breakup time of an OWP jet, and thus, it is calculated for a range of zirconium liners with different liner wall thicknesses. The calculated values of velocity difference gave a clear insight for the breakup time formulae for zirconium jet in terms of the liner thickness and the charge diameter.

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9

Burgun, Alexandre. "Oxidative activation of iron- and ruthenium-alkynyl complexes : toward square-shaped molecules with four redox-active metal centres." Rennes 1, 2011. http://www.theses.fr/2011REN1S081.

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Vestman, Christopher. "The rotation of a stored cylinder body by an outer rotating structure." Thesis, Luleå tekniska universitet, Rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-75021.

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HEAT-grenades are wing-stabilized grenades using shaped charge technology. Theshaped charge is a method, producing a jet-beam, with the use of a copper linerin which the aim is to focus the detonation energy to be able to penetrate armourand structures. This jet-beam is only eective under a rotational frequency of 15Hz, any frequency above this and the produced jet-beam loses its eciency and willnot be able to penetrate its target. One approach to minimize the inner body'srotation is by using bearings. By the use of ball bearings the intention is to with-hold transferring the angular momentum from the outer rotating body to the innercylinder body. This thesis have been analysing how much rotation the warhead haveacquired from the outer rotation of the grenade divided in an acceleration phase anda ying phase. During the acceleration phase the rotation of the warhead is reach-ing a frequency of 0.35 Hz. Proposals are presented for improving and lowering therotational speeds for future studies.

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11

Chambers, Nicholas Roy. "DESIGN AND NUMERICAL SIMULATION OF A LINEAR SHAPED CHARGE SEPARATION MECHANISM FOR FIRST STAGE SEPARATION OF THE ARES I LAUNCH VEHICLE." MSSTATE, 2009. http://sun.library.msstate.edu/ETD-db/theses/available/etd-04032009-084554/.

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This thesis developed a linear shaped charge (LSC) separation mechanism capable of severing the interstage skin for first stage separation of the Ares I launch vehicle. The derived LSC design solution was found using available data on Explosive Technologys Jetcord LSC and from National Aeronautics and Space Administration (NASA) Marshall Space Flight Centers (MSFC) desired characteristics. Mechanism components are designed after Minuteman IIIs separation mechanism for first stage separation and NASA MSFCs desired characteristics. Mechanism severance is verified through the use of the numerical method capability smoothed particle hydrodynamics that the hydrocode Autodyn offers. Three simulations are conducted to determine feasibility: the first of only the LSC exploding, to numerically validate the explosion process; the second of the LSC penetrating the target, to numerically validate the penetration process and failure mechanisms; and the last of the entire mechanism, to obtain information about the explosion, penetration, failure, and debris generated.

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12

Bingol, Cagin Gorkem. "Deformation Effects Of Straight Segment Of Flsc To Nearby Plates Due To Varying Backspace Distance." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/4/12605355/index.pdf.

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The objective of this study is to investigate the detrimental effects of a flexible linear shaped charge (FLSC) to variable thickness back and constant thickness front plates due to varying backspace distance. A FLSC is used to cut both metallic and non-metallic material, quickly and efficiently. It is flexible and may be formed to produce cuts of many configurations, thereby making it particularly useful where more conventional cutting techniques are difficult to employ. While performing its function, the FLSC gives some damage to the back due to the high transient pressure and fragmentation effects. In order to decrease this damage, a steel plate is placed behind the FLSC. In this work, a numerical analysis is carried out by using Autodyn Hydrocode for the investigation of the extent of the plastic deformation of the back as well as front plates for varying backspace distance of the steel plate having different thicknesses. The numerical results are then compared with the experimental findings. The flexibility property of the FLSC is not used in this study. Only the straight segment of FLSC is used.

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13

Johansson, Arvid. "Aktivt Pansar : Att nå verkan med dagens vapensystem i morgondagens pansar." Thesis, Försvarshögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:fhs:diva-4642.

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Då dagens vapensystem blir allt effektivare med högre penetration och större verkan är det inte längre möjligt att endast lägga på mer pansar för att få tillräckligt skydd. Fordonen blir för tunga och rörligheten påverkas negativt i allt för stor grad, därför börjar nu system för aktivt skydd slå sig in på marknaden. Dessa system söker aktivt av fordonets omgivning och skjuter ner inkommande hot såsom raketer och robotar och finns redan implementerade i en rad länder i vårt närområde. Infanteriets huvudbeväpning, som mot bepansrade hot traditionellt sett varit just robotar, raketer och granater, är i många fall verkanslös i mötet med aktivt pansar. Uppsatsen undersöker vilka möjligheter som finns att med den utrustning som dagens svenska försvarsmakt är utrustad med nå verkan i mål som är skyddade av aktivt pansar. De befintliga systemen för aktivt pansar Trophy, Iron Curtain och Arena har valts som exempelsystem. De vapensystem som granskas är STRIX, Rb56, Pskott m/86, Grg m/86 samt fordonsmina 14. En slutsats är att de granskade systemen alla saknar förmåga att skydda fordonet från hot som kommer rakt ovanifrån, detta medför att STRIX är fullt fungerande mot ett fordon skyddat av aktivt pansar.
Since today's weapons systems are becoming more efficient with higher penetration and greater efficacy, it is no longer possible to only put on more armor to get adequate protection. The vehicles become too heavy and mobility is adversely affected to an excessive degree, because of this systems for active protection are now breaking into the market. These systems are actively scanning the vehicle's surroundings and shoot down incoming threats such as rockets and robots and are already implemented in a number of countries in our region. The infantry's main armament against armored units, which traditionally have been just missiles, rockets and grenades are in many cases useless meeting with active protection systems. The paper examines the possibilities of reaching effect in targets equipped with active armor using the equipment available to the Swedish armed forces today. The existing active protection systems Trophy, Iron Curtain and Arena have been chosen as example systems. The weapons systems examined are STRIX , Rb56 , Pskott m/86 , Grg m/86 and Fordonsmina 14. One conclusion is that the audited systems all lack the ability to protect the vehicle from threats that come from directly above; this means that STRIX is fully functional to a vehicle protected by an active protection system.

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14

Johnsson, Fredrik. "Experimentellt vidareutvecklad modell för dimensionering av skadebegränsandeåtgärder mot RSV-penetration vid ammunitionsröjning." Thesis, Försvarshögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:fhs:diva-4708.

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Vid röjning av RSV-ammunition saknas idag adekvat beslutstöd för att dimensionera skadebegränsande åtgärder mot jetstrålens verkan. I uppsatsen vidareutvecklas en beräkningsmodell som författaren tidigare föreslagit. Syftet är att skapa ett verktyg som kan införas i ammunitionsröjningsverksamheten. Fullskaliga skjutförsök har genomförts för att klarlägga inverkan av förhållanden som är typiska vid ammunitionsröjning; en skyddskonstruktion byggd av sandsäckar och med ett långt detonationsavstånd till röjningsobjektet. Försöksresultatet visar att den grundläggande hydrodynamiska penetrationsteorin inte är användbar för dessa förhållanden. Vidare ger sandsäckskonstruktionen signifikant bättre skydd mot jetstrålen än en homogen grusbädd. Genom störningsanalys har känsligheten hos de enskilda parametrarna i beräkningsmodellen för verksamhetstypiska fel utretts. Härefter har Monte Carlo-simulering använts för att analysera den sammanlagda inverkan som dessa fel kan ge. Resultatet har legat till grund för att bestämma modellens säkerhetsmarginal. Militär nytta innebär att modellen skall kunna tillämpas fältmässigt, med korta tidsförhållanden och utan tillgång till avancerade beräkningshjälpmedel. Detta har lett fram till att ett enkelt diagram inkluderats i det kompletta dimensioneringsverktyget. Verktyget föreslås införas i regelverk och utbildningssystem för att avhjälpa den brist som råder idag.
During the clearance of shaped charge ammunition, explosive ordnance disposal (EOD) personnel lack adequate means for the design of protective measures against the jet. In this thesis a calculation model, previously suggested by the author, is developed further. The aim is to create a tool that can be applied to EOD operations. Full-scale experiments have been conducted to clarify the effects of conditions that are typical for EOD operations: protective measures built from sandbags with a long standoff distance to the ordnance. The results indicate that the hydrodynamic penetration theory is not suitable for these conditions. Furthermore, a sandbag construction provides significantly better protection against the jet than a homogeneous gravel construction. By disturbance analysis, the sensitivity of the individual parameters in the model is studied for typical errors. Subsequently, Monte Carlo simulation has been used to analyse the effect these errors can cause. The simulation results have then been the used to determine the model´s margin of safety. Military utility implies that it should be possible to use the model under field conditions, with limited time frames and without access to advanced calculating means. This has resulted in a simple diagram included in the comprehensive design tool. It is proposed that the tool is implemented in regulations and curricula in order to remedy today’s lack of decision support.

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15

Boman, Gustav. "Asymmetries in shaped charges." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297957.

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This thesis concerns the effects of a select few asymmetries on a jet formingshaped charge. A Shaped charge(SC) is a formed explosive with metal liner thatcollapses under the detonation. The resulting shockcompression results in a jetof metal being shot forward in up 10km/s. The asymmetries that were modelledare bubbles in the LX14 high explosive, rust on the copper liner and offcenterdetonation. To simulate the SC the software IMPETUS afea is used. By replacingthe geometry with SPH particles instead of a mesh, a simulation with broadboundaries is possible which helps in the simulation of explosives. The resultsshowedthattheoffcenterdetonationcausedthebiggestdeviationinthejet. Therustcausedfragmentationinthejetbutasmallerdeviationandthebubblescausedvery little damage to the jet formation

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16

Petersson, Jimmy. "Finkalibriga projektiler, RSV och penetrerande stridsvagnsminor : vad krävs av ett ballistiskt skydd för att undvika penetration från dessa stridsdelar?" Thesis, Swedish National Defence College, Swedish National Defence College, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:fhs:diva-827.

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Detta arbete syftar till att undersöka vilket konventionellt ballistiskt skydd som krävs för att undvika penetration från finkalibriga projektiler, RSV-stridsdelar samt penetrerande stridsvagnsmina. Arbetet tar sitt ursprung i en handbok utgiven av FMV där stridsdelar som kan förekomma i Afghanistan behandlas. Handboken anger data och prestanda för dessa stridsdelar och det är därifrån arbetet tar uppgifter om genomslagsförmåga för stridsdelen. Skyddsprinciper och verkansprinciper för stridsdelar hämtas i huvudsak från rapporter utgivna av FOI samt från litteratur utgiven av FHS. Arbetets beskrivande delar inleds med en redogörelse för homogena ballistiska skyddsmaterial av metall samt keramer. Därefter beskrivs verkans principer för finkalibriga projektiler, strålbildande RSV, projektilbildande RSV samt penetrerande stridsvagnsminor. Arbetet fortgår med en beskrivning av en finkalibrig projektil med kaliber 7,62*54R mm, hot av typen RPG-7 med tillhörande ammunition samt stridsvagnsmina TMK-2. Avslutningsvis presenteras resultat på vilket ballistiskt skydd som krävs för att skydda sig mot dessa stridsdelar samt en diskussion kring resultatet och alternativa lösningar på problemet. Det presenteras även några förslag på ny forskning inom området verkan och skydd.

This essay aims to investigate which conventional ballistic protection required preventing penetrationof small-caliber projectiles, shaped charged warheads and anti-tank mine. The essay takes its originin a handbook published by the Swedish Defense Material Administration, (FMV), where the warheads that can occur in Afghanistan are presented. The handbook present data of the warheads and it is from here information regarding the warheads penetration capabilities is taken. Effect principles and protection principles of the warheads are primarily gathered from reports published bythe FOI and from literature published by the National Defense College of Sweden, (FHS). The essays descriptional parts begin with an explanation of homogeneous ballistic protection materials fabricated in metal and ceramics. It then continues with a description of effect principles of small caliber projectiles, shaped charge projectiles, explosively formed projectiles and anti-tank mines. The essay then continues with a description of a small caliber projectile with caliber 7.62*54R mm, threats of RPG-7 type with its ammunition and the anti-tank mine TMK-2. In the end of the essay, results are presented according to the ballistic protection required to protect against the presented warheads, and a discussion of the result and alternative solutions to the problem.

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Bhullar, Anmol. "Velocity Compensation in Shaped Charges." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297800.

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Shaped charges (SC) have been used as a means of explosives in military andcivilian use for decades. Thus, there is a substantial amount of research behindthis area. However, as this is a sensitive subject much of this research is notpublicly available. This thesis will look at how one can use asymmetries in SC’s to velocity compensatethe jet formation. Velocity compensation is required when the SC is perpendicularto the projectile direction, hence, leading to an angled jet which decreases thepenetration potential. The asymmetries that were investigated are• off-center detonation• angled liner• displaced wave shaper• displaced wave shaper & angled liner. The 3D explosive simulation was conducted in IMPETUS AFEA solver and tocompare the performance of these asymmetries the position and velocity of thejet were measured. To create a baseline a simulation without any asymmetrieswas used. The off-center detonation showed some velocity compensating characteristicsat the tip of the jet. However, as the jet progressed it converged towards thereference. Angled liner simulations were conducted with an angle of 0.5 degrees and 1 degreeand these asymmetries behaved vastly differently. Angled Liner 0.5 degrees hada greater jet angle but a greater quantity of the jet particles were concentratedaround one point increasing the penetration potential. A general characteristicthat angled liner displaced was the fact that it had desirable velocity compensatingtraits all through the jet. Displaced Wave Shaper, like off-center detonation, showed promising velocitycompensating attributes at the tip of the jet, however, it too converged towardsthe reference on the later part of the jet. When combining the displaced wave shaper and angled liner asymmetries thedesire was to also combine their velocity compensating traits, i.e achievingthe displaced wave shaper’s tip compensation with the angled liner’s totalcompensation. Unfortunately, this was not achieved. The tip, again, showedpromising velocity compensating attributes but the rest of the jet convergedtowards the reference. Conclusively, angled liner shows the highest potential for compensating thevelocity and allowed the most amount of jet particles to be concentrated aroundone point increasing the penetration potential.

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18

Nemani, Neeharika. "Molecular Determinant of Mitochondrial Shape Change." Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/511170.

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Biomedical Sciences
Ph.D.
Mitochondria shape cytosolic Ca2+ (cCa2+) transients. Ca2+ entry into the mitochondria is driven by the highly negative mitochondrial membrane potential and through a highly selective channel, the Mitochondrial Calcium Uniporter (MCU). Mitochondrial Ca2+ (mCa2+) is utilized by the matrix dehydrogenases for maintaining cellular bioenergetics. The TCA cycle-derived NADH and FADH2 are mCa2+ dependent thus, feed into the electron transport chain (ETC) to generate ATP. Either loss of mCa2+ or metabolite uptake by the mitochondria results in a bioenergetic crisis and mitochondrial dysfunction. Reciprocally, sudden elevation of cCa2+ under conditions of stroke or ischemia/reperfusion injury (I/R) drives excessive mCa2+ overload that in turn leads to the opening of a large channel, the mitochondrial permeability transition pore (PTP) that triggers necrotic cell death. Thus, Ca2+ and metabolite equilibrium is essential to maintain a healthy mitochondrial pool. Our laboratory has previously showed that loss of mCa2+ uptake leads to decreased ATP generation and cell survival through autophagy. Although metabolite scarcity also results in similar reduction in ATP generation, the molecular mechanisms by which metabolites control mitochondrial ion homeostasis remain elusive. Deprivation of glucose or supplementation of mitochondrial pyruvate carrier (MPC) transport blocker UK5099 and or carnitine-dependent fatty acid blocker etomoxir triggered an increase in the expression of MICU1, a regulator of the mitochondrial calcium uniporter (MCU) but not the MCU core subunit. Consistently, either RNAi-mediated deletion of MPC isoforms or dominant negative human mutant MPC1 R97W showed significant induction of MICU1 protein abundance and inhibition of MCU-mediated mCa2+ uptake. Moreover, TCA cycle substrate-dependent MICU1 expression is under the control of EGR1 transcriptional regulation. Reciprocally, the MICU1 dependent inhibition of mCa2+ uptake exhibited lower NADH production and oxygen consumption and ATP production. The reduction of mitochondrial pyruvate by MPC knockdown is linked to higher production of mitochondrial ROS and elevated autophagy markers. These studies reveal an unexpected regulation of MCU-mediated mCa2+ flux machinery involving major TCA cycle substrate availability and possibly MICU1 to control cellular switch between glycolysis and oxidative phosphorylation. While mCa2+ is required for energy generation, sustained elevation of mCa2+ results in mitochondrial swelling and necrotic death. Hence, it was thought that preventing mCa2+ overload can be protective under conditions of elevated cCa2+. Contrary to this, mice knocked-out for MCU, that demonstrated no mCa2+ uptake and hence no mitochondrial swelling, however failed protect cells from I/R- mediated cell death. MCU-/- animals showed a similar infarct size comparable to that of control animals, suggesting that prevention of MCU-mediated mCa2+ overload alone is not sufficient to protect cells from Ca2+ -induced necrosis. The absence of mCa2+ entry revealed an elevation in the upstream cCa2+ transients in hepatocytes from MCUDHEP. Ultra-structural analysis of liver sections from MCU-/- (MCUDHEP) and MCUfl/fl animals revealed stark contrast in the shape of mitochondria: MCUfl/fl liver sections showed long and filamentous mitochondria (spaghetti-like) while MCUDHEP mitochondria were short and circular (donut-like). Furthermore, challenging MCUfl/fl and MCUDHEP hepatocytes with ionomycin caused a marked increase in cCa2+ and a simultaneous change in mitochondrial shape (from spaghetti to donut), a phenomenon we termed mitochondrial shape transition (MiST) that was independent of mitochondrial swelling. The cCa2+-mediated MiST is induced by an evolutionarily conserved mitochondrial surface EF-hand domain containing Miro1. Glutamate and Ca2+ -stress driven cCa2+ mobilization cause MiST in neurons that is suppressed by expression of Miro1 EF1 mutants. Miro1-dependent MiST is essential for autophagosome formation that is attenuated in cells harboring Miro1 EF1 mutants. Remarkably, loss of cCa2+ sensitization by Miro1 prevented MiST and mitigated autophagy. These results demonstrate that an interplay of ions and metabolites function in concert to regulate mitochondrial shape that in turn dictates the diverse mitochondrial processes from ATP generation to determining mechanisms of cell death.
Temple University--Theses

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Herkamp, John Frederick. "Deployment of shaped charges by a semi-autonomous ground vehicle." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Jun%5FHerkamp.pdf.

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Buchanan, Joni. "From Gàidhealtachd community to shared space." Thesis, University of Aberdeen, 2015. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=230099.

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This thesis explores the nature and impacts of social change in a remote rural, island area within the Scottish Gaidhealtachd. It seeks to contribute to an in depth understanding of how the social and economic system of crofting, as well as the Gaelic culture which has related closely to it in such areas, has evolved over the past 40 years. The case study area of South Uig in the Isle of Lewis has low population numbers and offers an opportunity to study these processes of change in microcosm. Where appropriate, inferences can be drawn from the study which may contribute to the formulation of policy for similarly remote rural places and the fragile cultures which are integral to them.

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Baker, Anna Bernadette. "4D materials : reversible shape change into hydrogels." Thesis, University of Bristol, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723490.

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Subramani, Praveen. "taking charge : optimizing urban charging infrastructure for shared electric vehicles." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/77815.

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Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 115-117).
This thesis analyses the opportunities and constraints of deploying charging infrastructure for shared electric vehicles in urban environments. Existing electric vehicle charging infrastructure for privately owned vehicles is examined and critiqued. A prototype of smartCharge, an integrated locking, charging, and ambient information system for shared electric vehicles is presented. Design methodology, fabrication of mechanical and electrical systems, and testing of the smartCharge system is documented. Urban implementation case studies for such a universal charging and locking station illustrate the potential of optimized infrastructure for shared vehicles to transform urban streetscapes and improve mobility. An analysis of leveraging existing building electrical infrastructure for vehicle charging is conducted, including phasing strategies for deploying rapid charging. Technological constraints to rapid charging such as battery chemistry, pack design, and power input are presented and evaluated. A strategy for buffering rapid electric vehicle charging with commercial uninterruptible power supply (UPS) systems is described. Two recent buildings on the MIT campus are used as case studies to demonstrate the overhead transformational capacity that exists in many modem, multi-purpose buildings. Connectivity between electrified transport, the electrical grid, and renewable energy sources is explored. A vision for personal urban mobility enabled by fleets of shared electric vehicles powered by clean, renewable energy and intelligent charging infrastructure is proposed.
by Praveen Subramani.
S.M.

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Johnsson, Fredrik. "Beräkningsmodeller för riktad sprängverkan vid ammunitionsröjning." Thesis, Försvarshögskolan, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:fhs:diva-2862.

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I arbetet görs en ansats att utveckla verktyg för dimensionering av skyddsåtgärder vid röjning av RSV-ammunition. Till skillnad mot övriga verkansformer så saknar ammunitionsröjaren idag beräkningsmodeller eller annat adekvat stöd för fastställande av maximalt riskområde respektive för dimensionering av skadebegränsande åtgärder vid röjning av ammunition innehållande riktad sprängverkan. Arbetets fokus utgår från den militära nyttan med ett sådant verktyg, då en anpassning till röjningsverksamhetens informationstillgång, tidsförhållanden, arbetsmetodik och tekniknivå är direkt avgörande för om ett verktyg kan anses ändamålsenligt eller ej. Resultatet utgörs av förslag på två kompletta verksamhetsanpassade verktyg. Det första i form av en beräkningsmodell för dimensionering av skadebegränsande åtgärder, vilken kombinerar RSV-strålens penetrationsförmåga med detonationsavståndets inverkan. Det andra verktyget är en enkel modell för bedömning av det maximala riskområde som en RSV-stråle kan ge upphov till, vilken baseras på det dimensionerande strålsegmentets ballistiska bana.
This thesis is an attempt to develop models for design of protective measures during clearance of shaped charge ammunition. Unlike for other hazards, the EOD personnel are lacking adequate means for the establishment of the maximum hazardous area and for the design of measures for hazard confinement against the shaped charge effect. The development of the models is based on the military utility, by consideration of the limited information availability, the short time frames, the working methods and the technology level that are characteristic for EOD operations. The result is a suggestion of two complete and adapted tools for the design of protective measures. The first tool is a model for the design of measures for hazard confinement, which combines the jet penetration depth with the influence of the stand-off distance. The second tool is a simple model for estimation of the maximum hazardous area generated by the shaped charge jet, which is based on the trajectory of the most critical jet segment.

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Giles, Adam R. "Deflection and shape change of smart composite laminates using shape memory alloy actuators." Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/7698.

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Shape memory materials have been known for many years to possess the unique ability of memorising their shape at some temperature. If these materials are pre-strained into the plastic range, they tend to recover their original un-strained shapes via phase transformation when subjected to heat stimulation. In recent years, this shape memory effect (SME) or strain recovery capability has been explored in aerospace structures for actuating the real-time movement of structural components. Among all the shape memory materials, the nickel-titanium based shape memory alloy (SMA) has by far received the most attention because of its high recovery capabilities. Since SMAs are usually drawn into the form of wires, they are particularly suitable for being integrated into fibre-reinforced composite structures. These integrated composite structures with SMA wires are thus called smart adaptive structures. To achieve the SME, these wires are normally embedded in the host composite structures. In returning to their unstrained shape upon heat application, they tend to exert internal stresses on the host composite structures in which they are embedded. This action could result in a controlled change in shape of the structural components. Although there has been a significant amount of research dedicated to characterising and modelling the SME of SMA wires, little experimental work had been done to offer an in-depth understanding of the mechanical behaviour of these smart adaptive polymeric composite structures. This project examined the deflection and shape change of carbon/epoxy and glass/epoxy cantilever beams through heating and cooling of internal nitinol SMA wires/strips. The heat damage mechanism and cyclic behaviour are major factors in the operation of such a system and need to be clearly understood in order to develop and gain confidence for the possible implementation of future smart actuating systems. Therefore, the objectives of the proposed research were to investigate (i) effect of embedding SMA, wires on mechanical properties of host composite, (ii) assessment of single-cycle and multiple-cycle actuation performance of smart beams, and (iii) thermal effects of excessive heat on the surrounding composite matrix.

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Shepstone, Lee. "Patterns of osteoarthritic bone change." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265454.

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Borget, Gisela Lilian. "Variation in arch shape and dynamics of shape change from infancy to early childhood." Thesis, University of Iowa, 2017. https://ir.uiowa.edu/etd/5421.

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Introduction: In order to properly diagnose and treatment plan, an orthodontist needs to be knowledgeable about the changes that occur to the maxillary and mandibular dental arches throughout growth. The purpose of this study is to provide an analysis of morphological shape differences seen in the maxillary and mandibular dental arches individually, as well as together, from birth to 3 years of age. Methods: Dental casts from the Iowa Infant Growth study ranging from 2 months to age 4 were photographed in the occlusal plane. The images were landmarked with 3 standard landmarks and 10 sliding semi-landmarks along the curvature of the maxillary and mandibular arches. TpsRelW was used to slide the semi-landmarks and superimpose the date to facilitate shape analysis. MorphoJ was used to determine the degree to which size influences dental arch shape. Once the effects of allometry had been removed, a principal component analysis was run on the residuals to display major features of shape variation in the dataset. Finally, a two block partial least squares analysis was run to determine the degree to which the maxillary and mandibular arches were integrated throughout early growth. Results: Allometry accounts for 9.63% of symmetric shape variation in the maxilla, while it accounts for 56% of symmetric shape variation in the mandible. Asymmetric shape variation is independent of allometry as it only affects 0.34% of the maxillary and 1.46% of the mandibular shape variation. Principal component one accounts for over 60% of all shape variation seen in maxillary and mandibular residuals. Principal component one of symmetric residuals results in a longer, wider dental arch or a shorter, narrower one. Principal component one of asymmetric residuals results in a dental arch with one posterior side being longer and wider while the contralateral side is shorter and narrower. The first three time points (2 months- 1 year) do not display significant integration between the maxillary and mandibular arches. Integration increases with age, displaying significant integration at the last three time points, with the most integration being displayed at 2.5 years. Conclusions: Allometry affects some of the symmetric shape variation in the maxilla, but over half of the symmetric shape variation in the mandible. The asymmetric components are independent of allometry. Integration of the maxillary and mandibular arches increase with age from 2 months to 3 years, peaking at a time point of 2.5 years.

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Busche, Matthew J. (Matthew James) 1978. "Multi-scale modeling of anisotropic polycrystalline plasticity in a shaped charged liner." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/89346.

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Li, Dongmei. "Effect of charge and shape on mobilities in capillary zone electrophoresis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0017/MQ49635.pdf.

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Rigg, Euan. "Fibre Bragg grating sensors for component shape change measurement." Thesis, Heriot-Watt University, 2004. http://hdl.handle.net/10399/247.

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Sjöberg, Johan, and Adam Tapper. "A business model shaped by technology : A case study of EMI Records." Thesis, Jönköping University, JIBS, EMM (Entrepreneurship, Marketing, Management), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-11248.

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Siefke, Brian Michael. "The Formation of Episodic Memory: How Context Change Shapes Distinctiveness." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500642787431847.

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Xing, Zhe. "A novel approach to control the shape change of a reconfigurable wing using shape memory alloy." Thesis, Cape Peninsula University of Technology, 2007. http://hdl.handle.net/20.500.11838/1266.

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Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2007.
Engineers and Technologists have found several approaches to control the shape of an aerofoil and improve the performance of a wing at different flow regimes; this research has been done at 2D level. In this work, a novel approach has been developed. The inspiration for this work comes from biological research. A 3D wing body has been modeled and flow conditions around it were simulated by advanced computer technology. The fabrication of the wing, based on the design optimization model, has been conducted using rapid prototyping technology. The unique thermal and mechanical properties that are exhibited by shape memory alloys (SMAs) have presented an exciting design possibility in the field of aerospace engineering. This kind of smart material was incorporated in the wing structure and when activated can alter the shape of the wing, thus effectively increasing the efficiency of a wing in flight, at several different flow regimes.

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Pevnyi, Mykhailo Y. "Induced shape changes in liquid crystal elastomers." Kent State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=kent1437989598.

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Travers, Margaret J. "Structural correlates of shape change in the primate crystalline lens." Thesis, City University London, 1990. http://openaccess.city.ac.uk/7669/.

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Cytological changes associated with accommodation in macaques and man were investigated using light and scanning electron microscopy to examine lenticular fibre modification and the role of the lens capsule. Accommodation was simulated monocularly in one animal with local administration of 1/4% phospholine iodide and by dislocation in another followed by fixation by perfusion. Three types of junctional structures were observed: angle processes were found at all depths, ball and sockets in outer lens zones, and tongue and grooves in the deeper lens. Interfaces lacking junctional structures were not present and the concept of sliding between fibre layers to permit curvature changes was rejected. The hypothesis of intracellular redistribution of cytoplasm within lens fibres was tested, by comparing fibre cross sectional area throughout the posterior half of accommodated and unaccommodated lenses. In one animal evidence for cytoplasmic flow was found throughout the lens but was greatest in the nucleus. In the other, showing less curvature difference, evidence was restricted the nucleu and superficial cortex. The thin superficial cortex is probably of little significance in effecting shape change. Consequently the results support the notion of greater nuclear than cortical action in accommodative shape changes. The fibres of the intermediate and deep cortex are remarkably thin and indented and are arguably less conducive to cytoplasmic flow. Lens capsule thickness was measured in 23 monkey and 11 human lenses in situ and detached, giving similar results. Profiles were recorded of unfixed monkey lenses with and without capsules. An annular zone of flattening, nearly coincident with maximum capsular thickness, giving the classical 'lenticonus" form, reduced on decapsulation. The young human and monkey capsule thickness variation was consistent with classical rather than more recent data thinnest at the posterior pole and thickest near, not at the equator. The results demonstrate a role for capsular shaping of the accommodated lens (with or without local moulding), effected by cytoplasmic flow most marked in the nucleus.

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Puzey, Joshua Robert. "Plant MicroRNA Evolution and Mechanisms of Shape Change in Plants." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10143.

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Plant microRNAs have been shown to have important roles in regulating diverse processes ranging from reproductive development to stress response. In the first two chapters, I focus on miRNA diversity in Aquilegia studying both anciently evolved broadly conserved and rapidly evolving species specific miRNAs. In chapter one, I utilize Aquilegia's critical phylogenetic position between the well developed models Arabidopsis thaliana and Oryza sativa to study the evolution of ancient miRNAs across the angiosperms. In chapter two, I utilize smallRNA high-throughput sequencing to annotate Aquilegia specific miRNAs and, in the process, uncover the novel regulation of a floral homeotic gene by an Aquilegia-specific miRNA. In chapter three, I look at the tissue specific development of miRNA regulation in the bioenergetically relevant model organism Populus trichocarpa. High-throughput smallRNA sequencing from four diverse tissue sets including leaves, xylem, mechanically treated xylem, and pooled vegetative and reproductive tissues were analyzed, revealing a total of 155 previously unannotated miRNAs, most of which are P. trichocarpa specific. Expanding on my work with the petal identity pathway, I turned a broader analysis of Aquilegia petal spurs. Petal spurs are the distinguishing characteristic of Aquilegia and are argued to be a key innovation in the adaptive radiation of the genus. In the fourth chapter, I explore the cellular basis of extreme spur length diversity in the genus and find that a single parameter, cell shape, can explain this morphological range. Next, I seek to describe the cellular patterns that give rise to a spur primoridia from an initially flat laminar petal and find that spur initiation is characterized by concentrated, prolonged, and oriented cell divisions. Inspired by this quantitative analysis of growth, chapter five looks at the mechanisms of shape change in cucumber tendrils. I find that anisotropic contraction of a multi-layered gelatinous fiber ribbon explains coiling in cucumbers. Surprisingly, we discover that tendrils display twistless-overwinding when pulled and exhibit an unforeseen force-extension response as a result. These results provide the design basis for twistless springs with tunable mechanical responses and serve as a clear example of how the biological systems can inspire applied mechanical designs.

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Kandel, Shreedhar R. "Control of Shape Change of PbSe Nano Structure by Chloroalkane." Bowling Green State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1435056285.

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Ying, Jia. "Structural Change and Its Assessment by Fluorescence Spectroscopy in Functional Polymers." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/192187.

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Billington, Neil. "Shape changes in myosin during the ATPase cycle." Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424054.

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McCarthy, C. J. "Effects of periodic temperature changes on crystal shape." Thesis, University of Bath, 1986. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370664.

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Mehrle, John. "Missed opportunities how district leadership and district policies shaped a 'schools within schools' change process /." [Bloomington, Ind.] : Indiana University, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3361500.

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Thesis (Ed.D.)--Indiana University, School of Education, 2008.
Title from PDF t.p. (viewed on Feb. 10, 2010). Source: Dissertation Abstracts International, Volume: 70-06, Section: A, page: . Adviser: Khaula Murtadha.

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Wong, Truman. "Dynamics of platelet shape change and aggregation size-dependent platelet subpopulations." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61778.

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Steele, Stephanie Chin. "Shape change for global vorticity shedding and added mass energy recovery." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104194.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 105-109).
To develop super-maneuverable underwater vehicles, one must consider how to quickly and efficiently transfer momentum between the solid body and its surrounding fluid. This thesis explores the efficient transfer of momentum to an energetic wake in the case of global vorticity shedding, as well as the recovery of momentum from the wake back to the body in the case of added mass energy recovery. Global vorticity shedding occurs when an object rapidly vanishes from the fluid. A rapid retraction is an approximation of a disappearing object, and as a result both the added mass energy as well as the entirety of the boundary layer vorticity that was originally attached to the body is deposited into the fluid. The globally shed boundary layer vorticity, under certain conditions, may evolve into lasting and coherent vortex structures that entrain the added mass energy due to the original body moving in the fluid. Such free vortices coming close to other bodies may result in large forces to effect transient motion; for example, this is how swifts can manipulate leading edge vortices generated on their wings to perform aerial acrobatics. Another example is the release of free vortices to affect bodies downstream, as in the case of fish extracting energy from an upstream wake generated either from a leading fish when within a school, or from a bluff rock as in the case of KirmAn gaiting. First we show experimentally and through simulation that the geometry of a retracting foil strongly affects the amount of deposited energy and the wake structure. A square-tipped foil, whose cross-section appears to 'vanish' in the observation plane when the foil is retracted, entrains all of the original added mass energy into its globally shed wake, but also entrains the added mass energy associated with strong ring vorticity generation at the tip, causing disruptive transient effects and incoherence in the globally shed wake. On the other hand, a streamlined-tipped foil, tapered in both the chord and thickness directions, appears to 'shrink' within the observation plane, and does not shed strong ring-like vorticity at its tip when retracted in the span-wise direction, but also sheds a much less energetic wake due to a gradually changing cross-section. Finally a hollow foil, in which the thin-walled cross-section appears to 'melt' within the observation plane, combines the best attributes of both previous geometries, avoiding the generation of strong ring vorticity at the tip, but ensuring the generation of a coherent, lasting, and fully energetic globally shed wake. Next, we demonstrate through numerical simulation and an extension of boundary vorticity flux analysis that the reduction of energy entrainment in the globally shed wake of the 'shrinking foil' is due to recovery of part of the original added mass energy by the foil through the generation of an additional pressure force. Though this recovery of energy is considered to be detrimental when the generation of strongly energetic vortical structures in the wake is desired, in other cases energy recovery is highly desirable. For example, added mass energy recovery can be used to our advantage in developing burst speed capability in flexible bodies, inspired by the impressive escape ability of octopodes enabled by their dynamic mantle shape change. For the octopus, the dynamic shape change, from an initially hyper-inflated nearly spherical shape to a streamlined ellipsoidal shape, allows for substantial added mass energy recovery from the fluid during fast jet escapes, that results in augmented thrust and much higher escape velocity than that provided by the octopus' jetting alone. While added mass energy recovery in flexible bodies is in principle possible, uncontrolled flow separation may result in substantially reduced recovery, when the energy is, instead, wasted in the formation of a large drag wake. We show through simulation and experimental validation that the amount of added mass energy recovery in a shrinking body within a viscous fluid is determined by a non-dimensional "shrinking parameter", defined as ... , where ... is the maximum shrinking speed, U is the characteristic flow velocity, and ... is the Reynolds number. We establish design criteria for shrinking bodies: Energy is recovered above a threshold value of ... 10, while operation in the range of 50 < ... < 100 results in good energy recovery, in the range of 61 - 82%.
by Stephanie Chin Steele.
Ph. D.

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Mu, Mulan. "Development of shape stable phase change materials with improved thermophysical properties." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.680062.

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Shape stable phase change materials (SSPCMs) based on paraffin wax (PW) and high density polyethylene (HDPE) can be used as energy storage materials for utilization of renewable energy in buildings. An SSPCM could be formed by selecting a suitable wax in terms of melting temperature (T m) and a HDPE in terms of viscosity. However, the impact of waxes with different T m and HDPEs with different viscosities on the manufacture of SSPCMs and their thermo-physical properties has not been studied thoroughly. Therefore, the aim of the research reported in this thesis is to understand the effect of different waxes and HDPEs on the processing of SSPCMs typically used in buildings and the quantification of their thermal and mechanical propelties. SSPCMs based on a higher (H-PW, Tm = 56-58°C) and a lower (L-PW, Tm = 18-23 0c) Tm wax with a higher (hv-HDPE, MFI = 0.18) and a lower (lv-HDPE, MFI = 25) melt viscosity HDPE were prepared by an extrusion method and their thermal and mechanical properties investigated. The effect of addition of thermally conducting multi-walled carbon nanotubes (MWCNTs) to enhance thermal conductivity and other properties of these SSPCMs was also studied. Such understanding would thus help to assess and inform the design of SSPCMs as wall panels suitable for domestic applications.

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Dickens, Peter Martin. "Facilitating Emergence: Complex, Adaptive Systems Theory and the Shape of Change." Antioch University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=antioch1339016565.

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Davenport, Emily. "The Next Catalyst for Change: How Corporate Shared Value is Reshaping Capitalism." Scholarship @ Claremont, 2011. http://scholarship.claremont.edu/cmc_theses/111.

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Both corporations and their global conglomerates are looking into the face of an evolving idea of capitalism. As businesses become more intertwined with society, this special relationship is becoming increasingly deterministic of the condition of the world. This paper explores the possibility that if businesses integrate shared value -- a way to combine economic and social value -- into their long-term business plans, that not only will society be better off, but the businesses themselves may be able to explore previously unrecognized potential for profits.

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Ho, Yuen Kim. "Structural damage identification with changes in vibration characteristics." Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251910.

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Booker, David Paul Alan. "Secular changes in Earth's shape and surface mass loading." Thesis, University of Newcastle Upon Tyne, 2012. http://hdl.handle.net/10443/1691.

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The changing distribution of surface mass (oceans, atmosphere, hydrology and cryosphere) causes detectable changes to the solid Earth’s shape on timescales from hours to millennia. Transient changes in Earth’s shape can be readily identified, but the tectonic plate movements and Glacial Isostatic Adjustment (GIA) will also influence the secular trends of Earth’s shape. To analyse secular trends in surface mass loading, these two confounding factors must be quantified. A suite of GPS-derived surface loading models, including both secular and transient terms is presented. Raw velocities are estimated from over 10 years of high quality combined global GPS position solutions, submitted as part of the first International GNSS Service (IGS) reprocessing campaign. A fiducial-free network approach is used with attention to estimating linear offsets and periodic signals. Consideration is given to realistic formal errors for station coordinates. A robust method is used for estimating horizontal and vertical linear velocities for all stations. Tests of the reprocessed data quality show that there is a dramatic improvement of the RMS of the weekly combined global network in comparison to the operational data used previously. The estimated Helmert transformations, when aligning the reprocessed frame to the IGS05 reference frame also show the stability and homogeneity of the new dataset. This permits a more precise estimate of individual station velocities, ~75% reduction to variability of Helmert parameters. Several a priori GIA models are applied to produce corresponding plate velocity estimates, leaving a range of computed residual surface displacements. Present-day surface mass loading is estimated from these residuals, using gravitationally consistent mass-conserving basis functions. GIA models are assumed to be error-free, so only nominal formal errors, with a white noise assumption, can be calculated, these will be adjusted to produce a realistic uncertainty value. Surface mass loading estimates show significant secular mass loss in Alaska and Greenland. The Greenland values (-140Gt/yr, 1999-2010) fall within published GRACE gravity mission values (-66 to -248Gt/yr, 2002-2009).

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48

Marshall, Frank Allison. "The stability of shape grammar applied to a bungalow built for change." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/21654.

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49

Martinez, Strömberg Valentin Erik. "Greenland: The Master Shaper of the Arctic? : A study about making change happen." Thesis, Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-154347.

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Abstract:

The Arctic region is changing. This is an oft-cited statement researcher, policy-makers and the general public say about the Arctic. But who can change the Arctic order? This academic paper is interested in determine Greenland’s role and ‘actorness’ in this changeable region. Adopting an interpretivist approach, I advocate to embrace the narrative turn in IR as a useful move to understand how Greenland, as a sub-state regional entity, can enhance its agency capacity in Arctic affairs. Using phronetical case study, govermentality and narrative analysis as main methodologies, this study decipher how the Arctic governance has changed and been shaped by different narratives and governmental practices. Greenland’s possibilities to exercise more power have been analysed through the lenses of ontological security theory because this theory is intimately related to human agency. However, this theory presents several challenges that must be overcome by doing a revision of the theory. The final results are discusses in a reflexive manner adopting four phronetical value-rational questions that policy-makers should take into account when planning any relevant strategic action, such as Greenland’s visibility and empowerment in Arctic affairs.

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50

Najrani, Majed. "The effect of change capability, learning capability and shared leadership on organizational agility." Thesis, Pepperdine University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10141724.

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Abstract:

Organizational agility represents a new field of organizational study that is not well examined. In the past organizations had an unmatched competitive advantage due to low competition and higher barriers to entry into their markets. As a result, many organizations dominated their industries. However, in the era of globalization, individuals with an internet connection and the right skills can start new organizations that can compete on a global level. Consequently, organizations now are facing more competition that they experienced in the past. Another reason for increase competition is new technology. Technology is improving increasingly faster than any time in history. Therefore, organizations that are not agile could not survive in the current environment.

Agile entities realize that they have to become flexible and nimble to withstand competition. Accordingly, the researcher in this study proposes an organizational agility model and this proposed model is the focus of the study. The proposed model significant arises from the fact that currently there are limited numbers of models that help organizations in becoming agile entities. The characteristics in this study were based on Worley and Lawler (2010) “Agility and Organization Design: A Diagnostic Framework”. The study conducted a survey utilizing an instrument developed by Dr. Worley and Dr. Lawler that contains 15 agility characteristics. The survey uses all 15 characteristics to determine if the organization is agile. In addition, the study utilizes three of the 15 agility characteristics to determent if a relationship occurs between the study variables.

This quantitative study examined the relationship between change capability, learning capability, shared leadership and organizational agility. Moreover, understanding these relationships could assist scholars and practitioners in producing change programs that emphasize certain behaviors that make an organization agile. The study surveyed 116 participants and found that focusing on change capability, learning capability and shared leadership could contribute in creating agile organizations. Consequently, after evaluating the study results, a new agility model emerged. This model shows that organizations can achieve agility by developing change capability, learning capability, shared leadership, shared purpose and flexible resources. Ultimately, achieving agility could help organizations compete and endure now and the future.

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Dissertations / Theses on the topic 'Shaped charge'

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