<p>Impact waves are used in many different industries and are classified according to whether they cause plastic or elastic deformations. In the plastic deformation mode, these waves can be used to produce special electrical joints. In the elastic deformation mode, they can be used to detect leakage or to measure the thickness of pipes. Both modes have applications in offshore technology. In this thesis the application of impact waves in the plastic deformation mode and explosive welding are discussed. In the explosive welding (EXW) process a high velocity oblique impact produced by a carefully controlled explosion occurs between two or more metals. The high velocity impact causes the metals to behave like fluids temporarily and weld together. This process occurs in a short time with a high rate of energy.</p><p>EXW is a well known method for joining different metals together. It is a multidisciplinary research area and covers a wide range of science and technology areas including wave theory, fluid dynamics, materials science, manufacturing and modeling. Many of the important results in EXW research are obtained from experimentation.</p><p>This thesis is mainly based on experimental work. However, it begins with a review of the fundamental theory and mechanisms of explosive welding and the different steps of a successful welding operation. Many different EXW tests are done on horizontal and vertical surfaces with unequal surface areas, and on curved surfaces and pipes. The remainder of the thesis evaluates the results of these experiments, measures the main parameters, and shows the results of simulations to verify the experimental results. The thesis ends with a number of suggestions for improving and optimizing the EXW process. One of these improvements is a model for joining metallic plates with unequal surface areas. An Al-Cu joint based on this model is used in the ALMAHDI aluminum factory, a large company in southern Iran that produces more than 200,000 tons of aluminum per year. Improved methods are also suggested for joining curved surfaces. These methods may have extensive applications in pipelines in oil and gas industries, especially in underwater pipes.</p> / <p>Impact vågor används i många olika branscher och klassificeras enligt de deformationer de orsakat: elastiska och plastiska deformationer. I plastisk deformation mode, dessa vågor skulle kunna användas för att framställa särskild elektrisk lederna. I deformationen läge, de skulle kunna användas för att upptäcka läckage eller mäta tjockleken på rören. Båda har tillämpningar inom offshore-teknik. I denna avhandling tillämpningen av effekterna vågor i plastisk deformation mode och explosiva svetsning diskuteras. I den explosiva svetsning (EXW) process hög hastighet sned effekt som produceras av en noggrant kontrollerad explosion uppstår mellan två eller flera metaller. Den höga hastigheten effekt gör att metaller gå ihop samtidigt som beter sig som vätskor. Denna process sker i en kort tid med hög energi.</p><p>EXW är en känd metod för att gå med olika metaller tillsammans. Det är ett tvärvetenskapligt forskningsområde och omfattar ett brett spektrum av naturvetenskap och teknik, inklusive våg teori, vätskor dynamik, materialvetenskap, tillverkning och modellering. Många av de viktiga resultat i EXW forskning har erhållits från experiment.</p><p>Denna uppsats bygger främst på experimentella verk. Det kommer dock att börja med en genomgång av grundläggande teori och mekanism av explosiva svetsning och de olika stegen i en lyckad welding operation. Då många olika EXW tester göras på horisontella och vertikala ytor med icke lika ytor och på krökta ytor och ledningar. Utvärdering av resultaten, som mäter de viktigaste parametrarna, som utför vissa simuleringar för att verifiera experimentella resultat och några förslag för att förbättra och optimera EXW process utgör de andra delarna av uppsatsen. En av dessa förbättringar är en modell för att gå med metalliska plattor med icke-lika ytor. En Al-Cu gemensamt bygger på denna modell används i ALMAHDI aluminium fabrik, ett stort företag i södra Iran att produktionen är mer än 200000 ton per år. Dessutom en del andra förbättrade metoder föreslås för att gå med krökta ytor. Dessa metoder kan få omfattande tillämpningar inom olje-och gasindustrin som rörledningar, särskilt under rören.</p>

<p>“In many interesting papers on discrete velocity models (DVMs), authors postulate from the beginning that the finite velocity space with "good" properties is given and only after this step they study the Discrete Boltzmann Equation. Contrary to this approach, our aim is not to study the equation, but to discuss all possible choices of finite phase spaces (sets) satisfying this type of "good" restrictions. Due to the velocity discretization it is well known that it is possible to have DVMs with "spurious" summational invariants (conservation laws which are not linear combinations of physical invariants). Our purpose is to give a method for constructing normal models (without spurious invariants) and to classify all normal plane models with small number of velocities (which usually appear in applications). On the first step we describe DKMs as algebraic systems. We introduce for this an abstract discrete model (ADM) which is defined by a matrix of reactions (the same as for the concrete model). This matrix contains as rows all vectors of reactions describing the "jump" from a pre-reaction state to a new reaction state. The conservation laws corresponding to the many-particle system are uniquely determined by the ADM and do not depend on the concrete realization. We find the restrictions on ADM and then we give a general method of constructing concrete normal models (using the results on ADMs). Having the general algorithm, we consider in more detail, the particular cases of models with mass and momentum conservation (inelastic lattice gases with pair collisions) and models with mass, momentum and energy conservation (elastic lattice gases with pair collisions).”</p>

Experimental work at the 1982 Dry Deposition Intercomparison Experiment (DDIEx) involved the use of optical particle counters for covariance estimates of dry deposition velocities of accumulation mode aerosols. Meteorological and particle flux observations are presented. Deposition velocity estimates exhibit scatter about zero. A formulation of the standard error of the deposition velocity estimator is derived and examined. Using this formulation, the observed deposition velocities are shown to be marginally significant. Using a case study, the correlation coefficient is examined and presented as an important statistic to the work. Humidity effects on the measurements are briefly examined. Recommendations are made for improvements in the instrumentation. / Graduation date: 1985

This paper presents some mathematical results concerning the measurement of motion of contours. A fundamental problem of motion measurement in general is that the velocity field is not determined uniquely from the changing intensity patterns. Recently Hildreth & Ullman have studied a solution to this problem based on an Extremum Principle [Hildreth (1983), Ullman & Hildreth (1983)]. That is, they formulate the measurement of motion as the computation of the smoothest velocity field consistent with the changing contour. We analyse this Extremum principle and prove that it is closely related to a matching scheme for motion measurement which matches points on the moving contour that have similar tangent vectors. We then derive necessary and sufficient conditions for the principle to yield the correct velocity field. These results have possible implications for the design of computer vision systems, and for the study of human vision.

The fact that many of the giant hydrocarbon reservoirs, such as the Ghawar field in Saudi Arabia and the Grosmont formation in Alberta, are formed from carbonates make these rocks important research topics. Compressional and shear wave velocities (at 1 MHz) and the quasi-static strains of thirty seven carbonate rock samples were measured as functions of saturating fluid and confining pressure. Furthermore, P- and S-wave velocities of the saturated samples were measured at constant differential pressure of 15 MPa. The quasi-static strains of the samples under jacketed and unjacketed conditions were also simultaneously acquired. The lithology, mineralogy, porosity and pore type and size distribution of each sample were obtained using a combination of thinsection and scanning electron microscopy, helium porosimetry and mercury intrusion porosimetry. Due to the lack of closing microcracks and compliant pores in low porosity samples, the travel times show slight changes with the confining pressure. Whereas the high porosity samples show remarkable reduction of travel time with the increase of confining pressure in both P- and S-wave. The samples show no changes in travel time with increasing confining pressure under constant differential pressure, and this behavior is taken to be representative of full saturation of the sample and hence used as a measure of quality control. The comparisons of Biot, Gassmann, squirt-Biot and squirt-Gassmann model predictions with the measured water saturated velocities show that the squirt mechanism is not active on all the studied samples. Biot mechanism is likely to be the principle dispersion mechanism in these samples. For S-wave velocities, Gassmanns model consistently over-predict the saturated at low pressure and closely fit the measured velocities at high pressure, whereas, Biot model over-predicts the saturated velocities in most of the studied samples. The strains over the horizontal axis are higher than the vertical axis suggesting that the majority of the compliant pores and crack-like pores are oriented almost in direction parallel to the length of the sample. The static bulk modulus is always lower than dynamic one for all measured samples. The measured grain bulk modulus is reasonably close to the bulk modulus of the constituent mineral. / Geophysics

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed on Feb. 6, 2007). PDF text: xii, 196 p. : ill., maps. UMI publication number: AAT 3220344. Includes bibliographical references. Also available in microfilm and microfiche format.

“In many interesting papers on discrete velocity models (DVMs), authors postulate from the beginning that the finite velocity space with "good" properties is given and only after this step they study the Discrete Boltzmann Equation. Contrary to this approach, our aim is not to study the equation, but to discuss all possible choices of finite phase spaces (sets) satisfying this type of "good" restrictions. Due to the velocity discretization it is well known that it is possible to have DVMs with "spurious" summational invariants (conservation laws which are not linear combinations of physical invariants). Our purpose is to give a method for constructing normal models (without spurious invariants) and to classify all normal plane models with small number of velocities (which usually appear in applications). On the first step we describe DKMs as algebraic systems. We introduce for this an abstract discrete model (ADM) which is defined by a matrix of reactions (the same as for the concrete model). This matrix contains as rows all vectors of reactions describing the "jump" from a pre-reaction state to a new reaction state. The conservation laws corresponding to the many-particle system are uniquely determined by the ADM and do not depend on the concrete realization. We find the restrictions on ADM and then we give a general method of constructing concrete normal models (using the results on ADMs). Having the general algorithm, we consider in more detail, the particular cases of models with mass and momentum conservation (inelastic lattice gases with pair collisions) and models with mass, momentum and energy conservation (elastic lattice gases with pair collisions).”

Impact waves are used in many different industries and are classified according to whether they cause plastic or elastic deformations. In the plastic deformation mode, these waves can be used to produce special electrical joints. In the elastic deformation mode, they can be used to detect leakage or to measure the thickness of pipes. Both modes have applications in offshore technology. In this thesis the application of impact waves in the plastic deformation mode and explosive welding are discussed. In the explosive welding (EXW) process a high velocity oblique impact produced by a carefully controlled explosion occurs between two or more metals. The high velocity impact causes the metals to behave like fluids temporarily and weld together. This process occurs in a short time with a high rate of energy. EXW is a well known method for joining different metals together. It is a multidisciplinary research area and covers a wide range of science and technology areas including wave theory, fluid dynamics, materials science, manufacturing and modeling. Many of the important results in EXW research are obtained from experimentation. This thesis is mainly based on experimental work. However, it begins with a review of the fundamental theory and mechanisms of explosive welding and the different steps of a successful welding operation. Many different EXW tests are done on horizontal and vertical surfaces with unequal surface areas, and on curved surfaces and pipes. The remainder of the thesis evaluates the results of these experiments, measures the main parameters, and shows the results of simulations to verify the experimental results. The thesis ends with a number of suggestions for improving and optimizing the EXW process. One of these improvements is a model for joining metallic plates with unequal surface areas. An Al-Cu joint based on this model is used in the ALMAHDI aluminum factory, a large company in southern Iran that produces more than 200,000 tons of aluminum per year. Improved methods are also suggested for joining curved surfaces. These methods may have extensive applications in pipelines in oil and gas industries, especially in underwater pipes. / Impact vågor används i många olika branscher och klassificeras enligt de deformationer de orsakat: elastiska och plastiska deformationer. I plastisk deformation mode, dessa vågor skulle kunna användas för att framställa särskild elektrisk lederna. I deformationen läge, de skulle kunna användas för att upptäcka läckage eller mäta tjockleken på rören. Båda har tillämpningar inom offshore-teknik. I denna avhandling tillämpningen av effekterna vågor i plastisk deformation mode och explosiva svetsning diskuteras. I den explosiva svetsning (EXW) process hög hastighet sned effekt som produceras av en noggrant kontrollerad explosion uppstår mellan två eller flera metaller. Den höga hastigheten effekt gör att metaller gå ihop samtidigt som beter sig som vätskor. Denna process sker i en kort tid med hög energi. EXW är en känd metod för att gå med olika metaller tillsammans. Det är ett tvärvetenskapligt forskningsområde och omfattar ett brett spektrum av naturvetenskap och teknik, inklusive våg teori, vätskor dynamik, materialvetenskap, tillverkning och modellering. Många av de viktiga resultat i EXW forskning har erhållits från experiment. Denna uppsats bygger främst på experimentella verk. Det kommer dock att börja med en genomgång av grundläggande teori och mekanism av explosiva svetsning och de olika stegen i en lyckad welding operation. Då många olika EXW tester göras på horisontella och vertikala ytor med icke lika ytor och på krökta ytor och ledningar. Utvärdering av resultaten, som mäter de viktigaste parametrarna, som utför vissa simuleringar för att verifiera experimentella resultat och några förslag för att förbättra och optimera EXW process utgör de andra delarna av uppsatsen. En av dessa förbättringar är en modell för att gå med metalliska plattor med icke-lika ytor. En Al-Cu gemensamt bygger på denna modell används i ALMAHDI aluminium fabrik, ett stort företag i södra Iran att produktionen är mer än 200000 ton per år. Dessutom en del andra förbättrade metoder föreslås för att gå med krökta ytor. Dessa metoder kan få omfattande tillämpningar inom olje-och gasindustrin som rörledningar, särskilt under rören.

Classical kinetic theory of gases is based on the Boltzmann equation (BE) which describes the evolution of a system of particles undergoing collisions preserving mass, momentum and energy. Discretization methods have been developed on the idea of replacing the original BE by a finite set of nonlinear hyperbolic PDEs corresponding to the densities linked to a suitable finite set of velocities. One open problem related to the discrete BE is the construction of normal (fulfilling only physical conservation laws) discrete velocity models (DVMs). In many papers on DVMs, authors postulate from the beginning that a finite velocity space with such "good" properties is given, and after this step, they study the discrete BE. Our aim is not to study the equations for DVMs, but to discuss all possible choices of finite phase spaces (sets) satisfying this type of "good" restrictions. We start by introducing the most general class of discrete kinetic models (DKMs) and then, develop a general method for the construction and classification of normal DKMs. We apply this method in the particular cases of DVMs of the inelastic BE (where we show that all normal models can be explicitly described) and elastic BE (where we give a complete classification of normal models up to 9 velocities). Using our general approach to DKMs and our results on normal DVMs for a single gas, we develop a method for the construction of the most natural (from physical point of view) subclass of normal DVMs for binary gas mixtures. We call such models supernormal models (SNMs). We apply this method and obtain SNMs with up to 20 velocities and their spectrum of mass ratio. Finally, we develop a new method that can lead, by symmetric transformations, from a given normal DVM to extended normal DVMs. Many new normal models can be constructed in this way, and we give some examples to illustrate this.

In the past the machinery used in punching of flexible printed circuit boards(FPCBs), it used mostly the rotary motor as the power source in the mechanism design. To transfer rotary motion to linear motion need a succession of mechanical conversion components, in order to achieve the purpose of linear output. However these mechanical parts for transforming bring some unavoidable problems such as the machinery itself huge volume, backlash and friction which created during the action process, all have harmful influences on the system dynamic performance and precision. Voice coil actuator has direct-drive output, high response and high thrust force these characteristics, therefore this research apply voice coil actuator to the punching of flexible printed circuit boards. For present industry, S-curve velocity profile is often used in point-to-point displacement intermittent action applications, due to its jerk-limited characteristic for reducing vibration and raising precision. Then integrating plans of S-curve velocity profile with voice coil actuator based on punching characters, to analyze the whole system dynamic performance in such a vertical linear output application. Then generalizing the dependence of influence factors of punching quality and motion characteristics of punching mechanism through experimental results. The achievement of this research could provide references for some related designers using similar linear actuators in vertical linear output applications.