Made available in DSpace on 2015-05-14T12:14:00Z (GMT). No. of bitstreams: 1 parte1.pdf: 2310445 bytes, checksum: 3cfca25ce861a7301fea8d5aa8526310 (MD5) Previous issue date: 2011-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work, we study the collective behaviour of living systems whose aggregates form organized groups such as flocks of birds, herds of mamals and schools of fishes. Through numerical simulations, we model the collective movement of a school of fishes using behavioural rules similar to the ones proposed by Couzin et al. [23], that investigates the spatial dynamics of animals groups. The model presents three interaction zones: repulsion, orientation and attraction. Our results for the distributions of nearest neighbour distance, the diference of orientation between the velocities of neighbour fishes and the cooperativeness of the school are in good agreement with experimental measurements. A simpler way to describe the collective motion of several groups of organisms was introduced by Vicsek et al. [10]. This model presents only one interaction region, called orientation zone and considers point particles moving off lattice at constant speed adjusting their direction of motion to that of the average velocity of their neighbors, being subject to some noisy term. A second-order transition between an ordered state and a disordered regime was found. However, Gregoire and Chate [12] contest the nature of such phase transition as being of first order. Indeed, this transition is related to the way of introducing the noise into the system. In this sense, we present a comparative study on noise in two system of self-propelled particle (Vicsek model and Gregoire model) with the aim of understanding the role of the noise on some observables such as polarization, distributions of the nearest neighbour distances, difference of orientations between neighbour particles, the order parameter and the Binder cumulant. / Neste trabalho, estudamos o comportamento coletivo de sistemas vivos cujos agregados formam grupos organizados tais como bandos de pássaros, rebanhos de mamíferos e cardumes de peixes. Através de simulações numéricas, modelamos o movimento coletivo de cardumes de peixes usando regras comportamentais similares áquelas propostas por Cousin et al.[23], que investigam a dinâmica espacial de grupos de animais. O modelo apresenta três zonas de interação: repulsão, orientação e atração. Nossos resultados para as distribuições das distâncias entre vizinhos mais próximos, a diferença de orientação entre as velocidades de peixes vizinhos e a cooperatividade do cardume estão de bom acordo com medidas experimentais. Uma maneira mais simples para descrever o movimento coletivo de vários grupos de organismos foi introduzido por Vicsek et al. [10]. Este modelo apresenta somente uma região de interação, chamada zona de orientação e considera partículas pontuais movendo na rede com uma velocidade constante ajustando sua direção de movimento à velocidade média de seus vizinhos, estando sujeita a algum termo ruidoso. Uma transição de segunda ordem entre um estado ordenado e um regime desordenado foi encontrado. Porém, Gregoire e Chaté [12] contestam a natureza da transição de fase como sendo de primeira ordem. Na verdade, está transição está relacionada à forma de introduzir o ruído no sistema. Neste sentido, apresentamos um estudo comparativo sobre o ruído em dois sistemas de partículas auto-propelidas (modelo de Vicsek e modelo de Gregoire) com o objetivo de compreender o papel do ruído em alguns observáveis tais como a polarização, distribuições das distâncias entre vizinhos mais próximos, diferença de orientação entre partículas vizinhas, o parâmetro de ordem e o cumulante de Binder.

Studien kopplar införandet av ett nytt självgående förbandsknutet bataljonsartilleri vid namn Granatkastarpansarbandvagn 90, GRKPBV 90 till teknisk tjänst. Studien tar en militärteknisk ansats då teknisk tjänst historiskt sett ofta blir förbisett i militära sammanhang. GRKPBV 90 bygger på en idé om ett självgående bataljonsbatteri som var på tal redan under 1990-talet vid namn Granatkastarpansarbandvagn 90120, men som ej förverkligades. Tidigare studier har visat att det kan finnas viss problematik vid införande av tekniska system med avseende på exempelvis teknisk tjänst. Det nya tekniska systemet GRKPBV 90 som ska införas i försvarsmakten kan bli komplext och kan ge en påverkan på militär verksamhet och i synnerhet teknisk tjänst. Studien kopplar den militära nyttan som är central i militär verksamhet till ett införande av ett nytt militärt tekniskt system och den tekniska tjänsten. Syfte: Studiens syfte är att utforska hur införandet av ett nytt tekniskt system, i detta fall GRKPBV 90, kan påverkar den tekniska tjänsten hos ett mekaniserat förband samt hur det kan påverka tillgängligheten av indirekt eldförmåga. Frågeställning: Hur påverkar införandet av GRKPBV 90 den tekniska tjänsten vid ett svensk mekaniserat förband? Metod: För att svara på den frågeställning som ställs nyttjar studien en kvalitativ metod i form av en fallstudie med innehållande litteraturstudie samt intervjuer. Resultat: Studien pekar på att införandets påverkan på den tekniska tjänsten för de mekaniserade förbanden kan komma att vara liten med avseende på struktur och utbildning. Anledningen till detta är GRKPBV 90 militära lämplighet, det vill säga systemets militära nytta. Den tekniska tjänsten kan dock blir mer belastad med avseende av att fler vagnar kan innebära fler mekaniker, verktygssatser och reservdelar. Sammantaget kan detta påverka den tekniska tillgängligheten på GRKPBV 90 och i sin tur tillgängligheten av indirekt eldförmåga. / The study deals with the introduction of a new self-propelled artillery called Granatkastarpansarbandvagn 90, GRKPBV 90, linked to technical service. The study takes a military technical approach, as historically, technical service is more than rarely overlooked in military contexts. GRKPBV 90 is based on an idea of a self-propelled battalion battery that was already under development in the 1990s, called Granatkastarpansarbandvagn 90120, but not realized. Previous studies have shown that there may occur problem when introducing technical systems with regard to, for example, technical service. The new technical system GRKPBV 90 that will be introduced into the Armed Forces can be complex and may affect military activity and, in particular, technical service. The military benefit that is central to military activity should be linked to the introduction of a new military technical system and the technical service. Purpose: The purpose of the study is to explore how the introduction of a new technical system, in this case GRKPBV 90, may affect the technical service of a mechanized unit and how it can affect the availability of indirect fire capability. Research question: How does the introduction of GRKPBV 90 affect the technical service of a Swedish mechanized connection? Method: To answer the question posed, the study uses a qualitative method in the form of a case study containing a literature study and interviews. Result: The study shows that the answer to the research question is that the impact of the introduction on the technical service of the mechanized links may be small in terms of structure and education. The reason for this is GRKPBV 90 military suitability, that is, the military utility of the system. However, the technical service may be strained with the fact that more vehicles can involve more mechanics, tool kits and spare parts. All in all, this may affect the technical availability of the GRKPBV 90 and, in turn, the availability of indirect fire capability.

Due to their diversity, soft matter systems provide a convenient platform to study a variety of physical phenomena like phase transitions and collective motion. Encompassing a wide range of equilibrium and non-equilibrium systems, they often provide significant insight into the statistical mechanics of different kinds of many-body systems. Though large scale properties of such systems are of fundamental interest in their own accord, since most experimental realizations of soft matter systems are finite sized, there is a growing need to understand the effects of confinement or boundary conditions on the collective behaviour of such systems. The primary purpose of this thesis is to study the effects of boundary conditions or confinement on both equilibrium and non-equilibrium soft matter systems via theoretical modelling. For equilibrium systems we have studied a system of colloidal particles in harmonic confinement, and for non-equilibrium systems we consider a system of self-propelled rods in both harmonic and hard wall confinement. In Chapter 1 we first lay down some basic concepts of stochastic dynamics and Brownian motion, before discussing some of the recent results on confinement effects on colloidal systems, showing how the properties of a finite sized colloidal system can be very different from those of large, un confined systems. Thereafter turning to non-equilibrium active systems, we discuss various fundamental problems posed by these systems due to their unique ability to generate and dissipate energy on their own. We also point out some instances of observed confinement effects in such systems, such as boundary aggregation and transient hedgehog-like clusters near the boundary. Chapter 2 deals with the effect of harmonic confinement on a finite sized colloidal assembly, where we show that such finite size effects coupled with a confining potential can give rise to special features like initial position dependent expulsion of dopant particles. First we model experimentally studied small two-dimensional colloidal assemblies trapped by a defocussed laser beam by Langevin dynamics simulations in the presence of harmonic confinement and demonstrate how the system shows a crossover from liquid state to crystalline state as a function of the stiffness of the confinement. We also show that in the crystalline state the system can be effectively modelled as a rigid body under small force perturbations. Notably, while studying the dynamics of a defect particle inside these crystallites, we found evidence for the occurrence of self purification by the crystallites. In this process, a dopant is spontaneously expelled out of the crystallite. Surprisingly, this phenomena has a strong dependence on the initial position of the dopant, which turns out to be the consequence of the non monotonic spatial variation of the free energy of the system as a function of the dopant position. This is caused by a difference in the rate of change of internal energy and entropy with the dopant position, with the entropy decreasing faster when the dopant is closer to the centre. This can be attributed to the amount of disruption of crystalline order in the assembly due to the incommensurate dimensions of the defect particle. In order to put these results in a general perspective, we verify in the last part of this chapter that the presence of this free energy barrier is independent of the exact functional forms of the confining potential and the interaction of a defect particle with the host particles, as well as the shape and size of the defect particle. Moving to non-equilibrium systems, we consider, in Chapter 3, the effect of harmonic and hard wall confinement on a two-dimensional system of self-propelled rods (SPRs). Though there have been very limited studies of confinement effects on such systems, existing studies are adequate to show that their behaviour near a boundary wall can be very different, e.g. formation of hedgehog like clusters near a boundary wall. First we show that for harmonic confinement small systems show polar order, which decays with system size, eventually going away for large systems. But the effect of hard wall confinement turns out to be rather different, where the system shows isotropic and clustered states depending on the values of activity and density. We construct a complete activity-density phase diagram showing four distinct phases. For high density and high activity, the rods spontaneously arrange themselves into a stable vortex structure in which the rods exhibit global radial polar order. Surprisingly this order does not decay with system size: the radial orientation of the rods exhibit strong spatial correlation even in large systems, ruling out the possibility that the radial order is a finite-size effect. Using other geometrical shapes of the hard wall boundary, we confirm this phase to be independent of the shape of the boundary. We also demonstrate how small modifications of the boundary conditions at the hard wall can collapse the clustered and vortex phases to a global flocking phase similar to that found in earlier studies of hydrodynamic active particles under confinement. Based on these observations, we conclude that the bulk of the system is strongly affected by the subjected boundary condition, which is rather unusual for large systems. In Chapter 4 this thesis concludes with a summary of the main results and suggestions for future work along similar lines

In this diploma thesis is documented an analysis and an approach of designing a self-propelled mobile reel mower with respect of general assumptions of industrial design. Thesis takes aim on a comparison of technologies of present manufacturers of garden equipment and proper choice and following application of technical solution and shape solution on a new product.

The Thesis with title " Armament production for Whermacht and the Army of Aliance in Protectorate of Bohemia and Moravia (1939 - 1945) is interested in detailed description of armament production within quality and quantity armoured of vehicles and infantry weapons made in war years 1939 - 1945 in Czech munition factories. Foreword part deals with Czech production efore Munich agrément,suitable conditions for militarization and empowerment German Army nor the use in industry either for strategy location. In following chapters the work describes main munition factories (Škoda Plzeň - Skoda Werke, ČKD Praha - BMM, Munition faktory Brno)and due to occupation our country,Czechoslovakia,maximal use of technical and human potenciál in Protectorate.The same it documents sale of spare weapons (cannons and munition) and presents German production,too. In other chapters it directs to confrontal of weapons,thein improvement,following development,army tanks, (mainly tank ŠKODA vz. 35, tank ŠKODA vz. 35,light tank LT vz. 38 and later fighter tank and offensive cannons from útočná ČKD Prague , Marder III, Hetzer, Grille), infantry weapons made in Brnopěchotní (Carabine Mauser K98 and gunmachine MG34, MG42, MG131). It mentios the biggest problem of German armament industry during War,that was critical shortage of raw...

A new suboptimal guidance law design approach for aerospace vehicles is proposed in this thesis, followed by an advanced control design for supersonic air-breathing engines. The guidance law is designed using the newly developed Generalized Model Predictive Static Programming (G-MPSP), which is based on the continuous time nonlinear optimal control framework. The key feature of this technique is one-time backward propagation of a small-dimensional weighting matrix dynamics, which is used to update the entire control history. This key feature, as well as the fact that it leads to a static optimization problem, lead to its computational efficiency. It has also been shown that the existing model predictive static programming (MPSP), which is based on the discrete time framework, is a special case of G-MPSP. The G-MPSP technique is further extended to incorporate ‘input inequality constraints’ in a limited sense using the penalty function philosophy. Next, this technique has been developed also further in a ‘flexible final time’ framework to converge rapidly to meet very stringent final conditions with limited number of iterations. Using the G-MPSP technique in a flexible final time and input inequality constrained formulation, a suboptimal guidance law for a solid motor propelled carrier launch vehicle is successfully designed for a hypersonic mission. This guidance law assures very stringent final conditions at the injection point at the end of the guidance phase for successful beginning of the hypersonic vehicle operation. It also ensures that the angle of attack and structural load bounds are not violated throughout the trajectory. A second-order autopilot has been incorporated in the simulation studies to mimic the effect of the inner-loops on the guidance performance. Simulation studies with perturbations in the thrust-time behaviour, drag coefficient and mass demonstrate that the proposed guidance can meet the stringent requirements of the hypersonic mission. The G-MPSP technique in a fixed final time and input inequality constrained formulation has also been used for optimal guidance of an aerospace vehicle propelled by supersonic air-breathing engine, where the resulting thrust can be manipulated by managing the fuel flow and nozzle area (which is not possible in solid motors). However, operation of supersonic air-breathing engines is quite complex as the thrust produced by the engine is a result of very complex nonlinear combustion dynamics inside the engine. Hence, to generate the desired thrust, accounting for a fairly detailed engine model, a dynamic inversion based nonlinear state feedback control design has been carried out. The objective of this controller is to ensure that the engine dynamically produces the thrust that tracks the commanded value of thrust generated from the guidance loop as closely as possible by regulating the fuel flow rate. Simultaneously, by manipulating throat area of the nozzle, it also manages the shock wave location in the intake for maximum pressure recovery with sufficient margin for robustness. To filter out the sensor and process noises and to estimate the states for making the control design operate based on output feedback, an extended Kalman filter (EKF) based state estimation design has also been carried out and the controller has been made to operate based on estimated states. Moreover, independent control designs have also been carried out for the actuators so that their response can be faster. In addition, this control design becomes more challenging to satisfy the imposed practical constraints like fuel-air ratio and peak combustion temperature limits. Simulation results clearly indicate that the proposed design is quite successful in assuring the desired performance of the air-breathing engine throughout the flight trajectory, i.e., both during the climb and cruise phases, while assuring adequate pressure margin for shock wave management.

The main aim of this master's thesis is innovative approach to design of self propelled sprayer with technical, esthetic, ergonomic and economic demands. The final design with it's modern and functional look should be an attractive element of agrotechnics. Another aim is also to fulfill social and psychological functions and address the public about protection of cultivated crops with emphasis on alternative energy and other uses of agricultural machinery.