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.

This experimental study consists of two parts. For the first part, the film cooling effectiveness for a single row of seven cylindrical holes with a compound angle is measured on a flat surface using five different measurement techniques: steady-state liquid crystal thermography, transient liquid crystal thermography, pressure sensitive paint (PSP), thermocouples, and infrared thermography. A comparison of the film cooling effectiveness from each of the measurement techniques is presented. All methods show a good comparison, especially for the higher blowing ratios. The PSP technique shows the most accurate measurements and has more advantages for measuring film cooling effectiveness. Also, the effect of blowing ratio on the film cooling effectiveness is investigated for each of the measurement techniques. The second part of the study investigates the effect of hole geometries on the film cooling effectiveness using pressure sensitive paint. Nitrogen is injected as the coolant air so that the oxygen concentration levels can be obtained for the test surface. The film effectiveness is then obtained by the mass transfer analogy. Five total hole geometries are tested: fan-shaped laidback with a compound angle, fan-shaped laidback with a simple angle, a conical configuration with a compound angle, a conical configuration with a simple angle, and the reference geometry (cylindrical holes) used in part one. The effect of blowing ratio on film cooling effectiveness is presented for each hole geometry. The spanwise averaged effectiveness for each geometry is also presented to compare the geometry effect on film cooling effectiveness. The geometry of the holes has little effect on the effectiveness at low blowing ratios. The laterally expanded holes show improved effectiveness at higher blowing ratios. All experiments are performed in a low speed wind tunnel with a mainstream velocity of 34 m/s. The coolant air is injected through the coolant holes at four different coolant-to-mainstream velocity ratios: 0.3, 0.6, 1.2, and 1.8.

Brightness enhancement film (BEF) has been manufactured in foreign factories for backlight module of liquid crystal display (LCD), then it only have some interior factories to put in exploitation. Because of this, the study presents a precision machining and new step-imprint hot embossing process to fabricate pyramid-shaped microlens array. First, a tungsten (W) steel material is manufactured by precision machining. The dimension of a pyramid-shaped microlens on the W steel are about 300 £gm in the base line of three side, 222 £gm in bevel edge of three side, 139 £gm in height of bottom to top, 180 £gm in pitch of the left and right sides between two pyramid-shaped microlens tips, and 85 degree in top angle of three bevel. The W steel mold is used as the first mold. Second, the pyramid peaks of first mold pattern are transferred on bulk metallic glass (BMG) using step-imprint hot embossing method with position adjustable mechanism to form a smaller concave pyramid-shaped microlens array, it can avoid arc radius of cutting tools which is used as the second mold. Another the pyramid peaks are transferred on PMMA (Polymethylmethacrylate) for concave pyramid-shaped microlens array of optical film in the hot embossing system. Finally, the second mold is fabricated to emboss convex pyramid-shaped microlens array of optical film on PMMA. The foregoing method is provided for backlight module of optical films process.

In this paper, we searched the parameter of BEF (Brightness enhancement film) using commercial FRED server for backlight module. The pattern analysis was carried out to understand its characteristic. The current structures used in LCD backlight are double-layer BEF. In addition, BEF of 3M takes the lion¡¦s share. But this may increase the thickness and cost of backlight module. In order to avoid those disadvantages, we tried to design single-layer BEF and characterize the effect through parameters study by using FRED software simulation. pyramid-shaped microlens array of BEF was constructed. Therefore, the effect of the variation of the structure parameters can be analyzed, such as prismatic degree (£c), prismatic structure on the brightness enhancement. It can be found from the result of simulation that the changes of the prismatic degree (£c) of 85 degree influence the brightness enhancement the most.

Film cooling is used in gas turbine engines to cool turbine components. Cooler air is bled from the compressor, routed internally through turbine vanes and blades, and exits through discrete holes, creating a film of coolant on the parts’ surfaces. Cooling the turbine components protects them from thermal damage and allows the engine to operate at higher combustion temperatures, which increases the engine efficiency. Shaped film cooling holes with diffuser exits have the advantage that they decelerate the coolant flow, enabling the coolant jets to remain attached to the surface at higher coolant flow rates. Furthermore, the expanded exits of the coolant holes provide a wider coolant distribution over the surface. The first part of this dissertation provides data for a new laidback, fan-shaped hole geometry designed at Pennsylvania State University’s Experimental and Computational Convection Laboratory. The shaped hole geometry was tested on flat plate facilities at the University of Texas at Austin and Pennsylvania State University. The objective of testing at two laboratories was to verify the adiabatic effectiveness performance of the shaped hole, with the intent of the data being a standard of comparison for future experimental and computational shaped hole studies. At first, measurements of adiabatic effectiveness did not match between the labs, and it was later found that shaped holes are extremely sensitive to machining, the material they are machined into, and coolant entrance effects. In addition, the adiabatic effectiveness was found to scale with velocity ratio for multiple density ratios and mainstream turbulence intensities. The second part of this dissertation measures heat transfer coefficient augmentation (hf/h0) at density ratios (DR) of 1.0, 1.2, and 1.5 using a uniform heat flux plate and the same shaped hole geometry. In the past, heat transfer coefficient augmentation was generally measured at DR = 1.0 under the assumption that hf/h0 was independent of density ratio. This dissertation is the first study to directly measure the wall and adiabatic wall temperature to calculate heat transfer coefficient augmentation at DR > 1.0. The results showed that the heat transfer coefficient augmentation was low while the jets were attached to the surface and increased when the jets started to separate. At DR = 1.0, hf/h0 was higher for a given blowing ratio than at DR = 1.2 and DR = 1.5. However, when velocity ratios are matched, better correspondence was found at the different density ratios. Surface contours of hf/h0 showed that the heat transfer was initially increased along the centerline of the jet, but was reduced along the centerline at distances farther downstream. The decrease along the centerline may be due to counter-rotating vortices sweeping warm air next to the heat flux plate toward the center of the jet, where they sweep upward and thicken the thermal boundary layer. This warming of the core of the coolant jet over the heated surface was confirmed with thermal field measurements. / text

ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / Over the past decade, SOQPSK has been widely adopted by the flight test community, and the low density parity check (LDPC) codes are now in widespread use in many applications. This paper defines the waveform and presents the bit error rate (BER) performance of SOQPSK coupled with a rate 2/3 LDPC code. The scheme described here expands the transmission bandwidth by approximately 56% (which is still 22% less than the legacy PCM/FM modulation), for the benefit of improving link margin by over 10 dB at BER = 10⁻⁶.

Building Information Modeling (BIM) is the comprehensive process of developing a computer model of a building project in the phases of designing, analyzing, building, managing, refurbishing and even demolishing the building. Applying BIM to public construction has become an obligation in South Korea. According to the Public Procurement Service in South Korea, the use of BIM has been compulsory on all government projects over $44M since 2012. Moreover, from 2013, the application of BIM will be expanded to all public construction projects over $27.6M. Finally, beginning in 2016, all public construction projects will be required to use BIM. Most research on BIM in South Korea has been focused on developing regulations and policies, application of BIM, solving technical problems, and searching for the value of BIM. However, the use of BIM in Korea during construction for decision-making has not been thoroughly reported in Korea yet. One may be wondering then if BIM is indeed well utilized in Korea during construction for practical decision-making. The objective of this research centers on investigating how a construction company in South Korea is using BIM for its decision making process during ongoing construction phases. For this investigation, a case study method was used. The construction operations on a jobsite in South Korea were monitored June to August in 2012. Field notes were taken to document the decision-making process and information used during field coordination meetings. A total of 36 cases were monitored and recorded. The use of BIM on field was then compared to the industry expectations indicated in the literature. Specifically, the use of BIM for scheduling, estimating, coordination, review of drawings, and tracking for change orders were carefully monitored and compared with the industry expectations as they were addressed in the literature. The results of this research study were mixed. That is, there are not only similarities, but also differences between BIM’s role used for decision making at the construction site, and its expected role described in previous research. The similarities were regarded as minimizing reworking. This factor came to fruition at a construction site by minimizing error, omission in design phases, or congruence in design and construction tasks. These factors could have a positive effect on estimating and scheduling at a construction site. However, use of BIM at a construction site was still limited in reducing repetitive work when 2D drawings were not able to provide enough information to conduct construction. Additionally, even though this study was successful in revealing the connection between the decision making process and the application of BIM at a construction site, the results of the study may not be generalizable to the construction industry as a whole in South Korea. Therefore, further research is needed to ensure its applicability to other construction projects.

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.

Η παρούσα εργασία ασχολείται με την εξομοίωση σε προγραμματιστικό περιβάλλον, της λειτουργίας συστοιχιών ηχείων κάθετης διάταξης και συγκεκριμένα για τις περιπτώσεις ευθύγραμμων (Uniform) και υβριδικού τύπου (J-Shaped) συστοιχιών, σε περιβάλλον ανοιχτών και κλειστών χώρων. Οι εξομοιώσεις που υλοποιήθηκαν επιτρέπουν την αξιολόγηση και σύγκριση των συστοιχιών σε θέματα εκπομπής, εστιάζοντας στην ηχητική κάλυψη των επιπέδων ακρόασης. Επιπλέον, αναπτύσσονται τα εργαλεία για την εξομοίωση και μελέτη του διάχυτου πεδίου που παράγεται κατα τη λειτουργία των συστοιχιών σε κλειστούς χώρους. / The current thesis is about simulating the function of Uniform and J-Shaped line arrays in open and closed space. It also allows the comparison among between the two types af arrays in terms of beaming and sound coverage especially at the audience planes. Furthermore, tools of simulation of the diffuse field are being developed.

Este trabalho tem como propósito, investigar a validade da lei de Hess-Murray, através da experimentação numérica, aplicando o método do Design Construtal associado ao método de otimização da busca exaustiva, no escoamento interno em estruturas em forma de T com seção circular. Variação do número de Reynolds, escoamento de fluidos newtonianos e não newtonianos, estrutura em forma de T com paredes impermeáveis e permeáveis, foram as principais características avaliadas para confrontar a lei de Hess-Murray. O estudo proposto assume escoamento tridimensional, laminar, incompressível, regime permanente e propriedades fluidodinâmicas constantes, sendo o regime de escoamento governado pelo número de Reynolds (Re). O objetivo principal consiste em determinar as configurações ótimas que facilitem o escoamento de fluido ou minimizem as resistências ao escoamento, quando a área ocupada pelos dutos (A) e o volume ocupado pelos dutos (V) são mantidos constantes, variando-se as razões de diâmetros (aD) e comprimentos (aL). As equações de conservação de massa e quantidade de movimento, foram resolvidas através do método de volumes finitos. A geometria foi discretizada através de uma malha tridimensional composta por aproximadamente 1.950.000 elementos. Como resultados, obteve-se as geometrias ótimas que apresentaram resistências ao escoamento até 30 vezes menor do que as demais configurações. Além disso, foi possível verificar que a lei de Hess-Murray nem sempre é válida, visto que o sistema adapta sua geometria ótima para cada condição de escoamento, a fim de proporcionar a melhor arquitetura de escoamento para atender ao objetivo de minimizar as resistências ao escoamento em acordo com a Lei Construtal. Esta dissertação avançou no presente estado da arte, pois desenvolveu um modelo tridimensional sem simplificações, aplicado ao sistema de escoamento de fluidos em estrutura em forma de T utilizando o método do Design Construtal, validando os resultados analíticos apresentados na bibliografia e apresentando novas referências que permitem ampliar a complexidade dos sistemas de escoamento bem como a implementação de métodos de otimização mais avançados. / This work investigates, through the numerical experimentation together with the Construtal Design method, the Hess-Murray Law in the internal flow in T-shaped structures with a circular section for the laminar flow of Newtonian and non-Newtonian fluids with impermeable and permeable walls, determining the optimal configurations that facilitate fluid flow or minimize flow resistance. The geometric global constants, the volume occupied by the ducts (V) and the area occupied by the ducts (A), delimit the space occupied by the T-shaped structure and the degrees of freedom, the ratio between the diameter of the parent duct and daughter (aD) and the ratio between parent duct length and daughter (aL), are the main geometric parameters to be evaluated. The proposed study is assumed three-dimensional, laminar, incompressible, permanent and constant fluidodynamic properties being the flow regime governed by Reynolds number (Re). Construtal Design method, associated with the exhaustive search, was used to determine the global geometric constants, degrees of freedom and objective function in the geometric evaluation of the system. The numerical solution of the mass conservation and momentum equations is solved based on the finite volume method. The geometries and mesh of the computational domain was discretized through a three-dimensional composed of approximately 1,950,000 elements. The results show that the optimal geometries that presented resistance to the flow up to 30 times smaller than the other configurations. In addition, it was possible to verify that the Hess-Murray Law is not always valid, since the system adapts its optimal geometry to each flow condition, in order to provide a better flow architecture to meet the objective of minimizing resistance to flow in agreement with the Constructal Law. This work advanced in the present state of the art, since it developed a three-dimensional model without simplifications, applied to the fluid flow system in T-shaped structure using the Construtal Design method, validating the analytical results presented in the bibliography and presenting new references that allow increase the complexity of flow systems as well as the implementation of more advanced optimization methods.