Designing a safe and economical mining activity is the main goal of every mine design engineer. With the rise of computer modeling in mine design there is a need for a standardized method to use geologic characterization of rocks in engineering design. In this research, first a review of empirical methods will be conducted and after that a step-by-step method is presented to adequately use FLAC3D, for development pillars, in room and pillar mine in development stage. ARMPS database is used to evaluate the FLAC3D model results. ARMPS database consists of 645 case study in room and pillar mines. 170 of them are mines in development phase. In this research all 170 cases will be analyzed in FLAC3D v4.0 and the results will be compared to actual success and failure from the database. Also, the stability factor found from FLAC3D will be compared to ARMPS. Finally, it is tried to calibrate FLAC3D stability factor so it can be used in room and pillar design.

Highwall mining is a mining method used in surface coal operations that involves driving a series of parallel entries into the exposed coal seam at the highwall face under an unsupported roof leaving behind a series of long, but very slender coal pillars. Highwall mining often occurs simultaneously with production blasting taking place in other areas of the mine. Although no failures of highwall pillars have been attributed to nearby blasting, numerical modelling presents an inexpensive means of investigating the possible effects of strong ground motion on the stability of these pillars. This thesis documents the development of a discrete element rock mass model and its application to the simulation of both static and fully dynamic highwall pillar simulations. The approach is geared toward parameter analysis and mechanism identification rather than exact prediction. Some conclusions are made regarding the potential effects of blast vibration on highwall coal pillars and general excavations in rock. The limitations of the modelling approach are discussed and suggestions for future research are proposed.

This study aims to explore the relationship between the cost of debt and ESG reporting disclosure and performance. The extant literature presents mixed findings, with some studies establishing a significant negative relationship between the variables, while others report inconclusive or even positive results. Our analysis of 1,012 Nordic non-financial firms listed from 2011 to 2019 reveals that ESG reporting disclosure has a significant negative relationship with the cost of debt for some models, whereas ESG performance shows an insignificant relationship across all models. The variability in ESG rating methodologies and the time period of data collection are potential factors influencing these mixed results. Limited access to ESG data, selection bias, and survivorship bias also pose challenges to the analysis.

The company Rio Deserto is currently mining the famous Barro Branco coal seam in the state of Santa Catarina located in the south of Brazil. One of their coal mines, #101, is experiencing problems related to the pillars in one panel. The coal seam is slightly inclined and several pillars have developed damages on the down-slope side with focus in the top corner. Damage inspections revealed a thin clay layer located between the coal pillar and the overlying siltstone. The clay layer is believed to affect the pillar strength and possibly be a source for the observed damages. Aim of this report has been to evaluate different theories behind the damages, focusing on the clay interface using numerical modelling with FLAC. Using convergence data, a calibration of the model is initially done before evaluating the combination of different interface and coal strength while observing the pillar. In addition is an evaluation of influence from structures such as cleats/joints. The results clearly show that with a small shear displacement (1-4 mm) the pillar damages are almost symmetrical on the up-slope and down-slope side of the pillar. Structures can influence and contribute to non-symmetrical pillar damages although not perfectly matching the field observations. Furthermore, the results show that a forced shear movement (8-25 mm) best reproduce the observed damages. A shear movement along the interface is therefore believed to be source mechanism behind the pillar damages. The forced shearing can potentially be explained by factors not considered in the model such as horizontal stresses, disturbances by mining and presence of water within the clay.

Novel fabrication technologies for high performance electrical and optical chip-to-substrate input/output (I/O) interconnections were developed. This research is driven by the long term performance and integration requirements of high performance chip-to-substrate I/Os, as well as the package reliability demands from semiconductor manufacturing. An electroless copper plating and annealing process was developed to join copper structures to achieve chip-to-substrate assembly by all copper pillar interconnects. The developed copper pillar interconnects provide much higher current carrying capability for chip-to-substrate power/ground input/output distributions and have low electrical parasitic characteristics for high frequency electrical signal communications. This copper bonding process also demonstrates the capability to compensate for misalignments and height variations of bonded structures. A finite element generalized plane deformation model was employed to design fully compliant copper pillars to eliminate the need of underfill. Electrical parasitics of copper pillar chip-to-substrate interconnects were studied by the derived formulas for low parasitic requirements. An optimized dimension space for all the criteria was provided on the pillar dimension chart. A novel nanoimprint lithography was developed to combine with photolithography in one process to create high quality features on a macrostructure for chip-to-substrate optical I/O applications. This fabrication process also demonstrated the capability to produce off-angle complex structures.

In this thesis, we fabricate the quantum dots (QDs) micro-pillar of metal-coated by E-beam lithography, and analyze the optical and electrical properties of micro-pillar cavity devices. For the sample materials, we use S-K mode to grow 3-layer In0.75Ga0.25As QDs structures sandwiched by up and down Al0.5Ga0.5As cladding layer on GaAs substrate by molecular-beam epitaxy (MBE). 40nm GaAs spacer layers with 2nm p-modulation doping in the central barrier are adopted in this study. The micro-pillar with diameter of 2 m, metal coated on top (p-type) and down (n-type) facet are designed. The good reflectivities of metal contacts provide more energy extraction inside the cavity. We expect the device lasing while the current injection. First, we design the morphology and size of patterns by AutoCAD software. Then, we use e-beam lithography with proper exposure condition to define the patterns, and thermal evaporation to deposit metals. The superfluous metal is lifted off and the defined area metal is served as dry etching mask to transfer the pattern to the dielectric layer and epi-layer. Finally, we use SiO2 layer to prevent current leakage, and the p-n contact on each facet to complete the devices. Micro-pillar samples with/without metal coated are analyzed by micro-PL system. The emission wavelength of 1282nm and the calculated Q-value of 100 are obtained for the sample with metal coated, an increase of 500%. From the EL measurement results, the device of micro-pillar samples with metal coated generate three peaks, 1149nm, 1221nm and 1291nm. Besides, it can efficiently improve the emission intensities. The measured result matched the simulation result.

The electromigration (EM) and chip-package interaction (CPI) reliability of flip chip packages with Cu pillar structures was investigated. First the EM-related characteristics of Cu pillars with solder tips were studied and compared with standard controlled collapse chip connection (C4) Pb-free solder joints. The simulation results revealed a significant reduction in the current crowding effect when C4 solder joints was replaced by Cu pillar structures. As a result, the current-induced Joule heating and local temperature gradients were reduced in the Cu pillar structure. This was followed by a study of the impact of the Cu pillar bumps on the mechanical reliability of low-k dielectrics. The CPI-induced crack driving force for delamination in the low-k interconnect structure was evaluated using a 3D sub-modeling technique. The energy release rate was found to increase significantly for packages with Cu pillar bumps compared with those with C4 Pb-free solder joints only. Structural optimization of Cu pillar bumps to improve the mechanical stability of packages with low-k chips was discussed. / text

A roof above your head, when in a car, is made possible due to the component calledthe A-pillar in the automotive industry. This component is not only responsible forholding up the roof but also in providing a point for the windscreen to be attached.Hence, it is denitely a part that can not be done away with and any problems arising from it must be solved. The flow over the A-pillar causes formation of vortices which causes an increase in the drag generated by the vehicle. These vortices also cause a high level of noise to be generated, which can cause discomfort inside the vehicle, when it is in motion. Hence, there is a need in the automotive industry to modify the A-pillar so as to reduce the generated drag and noise caused by it. In this thesis, the flow around the A-pillar is analyzed and modications are made accordingly to reduce the impact of the vortices formed due to it. The final resulting design of the A-pillar which has been modied from the aerodynamics and aeroacoustics point of view has been presented. This thesis project also includes the optimization of the method used to implement this. The method involved in obtaining an optimized design of the A-pillar started with the geometry cleaning phase in ANSA, followed by the meshing and simulation phase in FLUENT and finally concluding with the optimization phase in HEEDS. The process of doing this methodology has now been optimized resulting in lesser times between the models being cleaned and optimized. The baseline model obtained from these simulations has been validated by comparing the flow around the vehicle to other works and literature studies. This was done to be certain that the optimization method works to provide correct and accurate results. The optimized design, which called for an increased height was then compared against the baseline model, to understand the flow behavior that lead to the reduction of the output variables.

This Thesis discusses the pension system issues in the Czech Republic depending on a demographic situation. The first chapter affords the historic review of pension systems and shows information concerning actual applications. The second chapter is aimed at the financial variations of the pension system. The third chapter is focused on a basic description of the contemporary pension system in the Czech Republic and historic evolution as well. In the fourth chapter, there is made an excurse throught the reformed pension systems abroad. This is provided in case of post-communist countries as well as the Latin America`s country. In the fifth chapter, there is realized an appropriate analysis of financing the actual pension system in dependence on a population evolution. There is proved an indefensibility of PAYG model through the use of a mathematic model. At the begining of the closing chapter there is a conception of each political party. The second part of its is represented by own summary and conception of this "stalemate" situation.

Main goal of the Master thesis is comparsion of present pension systems in Germany, Austria, Poland, Hungary, Czech Republic and Slovakia. It compares not only compulsory pay as you go pillars but even structural reforms of past twenty years, implementation of the 2nd funded pillar in post-communist countries and motivational schemes of the 3rd pillar. The Master thesis briefly touches history and development of pension systems in the region of Central Europe. Using the metod of on-line survey it discovers base kowledge bound with pensions, demographical issues and future problems of the system. Analyse of the written and on-line sources and results of the survey followed by synthese closes the Thesis with set of recommendations how to upgrade all three pillars of conterporary pension system in Czech Republic.