Master of Science / Department of Architectural Engineering and Construction Science / Fred L. Hasler / Presently, the design basis for urban areas with a scarcity of surface space is the construction of skyscrapers. Skyscrapers, even with a lot of challenges, have been a great solution for the development of large urban areas since their introduction, per modern definition, in the early 1900’s (Kelley, 2010). This has allowed us to have a “reach a new height” type of mentality, with which the industry has been able to develop new construction ideas and concepts to improve, if not reinvent, those that have been used for nearly a century. The appreciation and application of new concepts will lead us into a progressive path to improve the overall designs within the industry. The concept of earthscrapers, best described as an underground skyscraper, is very intriguing but more than anything attractive to those in the industry. These new concepts will also bring a set of new challenges, with which solutions will arise. The concept of earthscrapers is a major game changer, with a design that offers several comparison and contrast points to skyscrapers. Some of the main focus points when discussing the approach of designing earthscrapers in comparison to skyscrapers are its space constraints, structure stability, and energy efficiency. Consequently, the paper will review the technical literature within the industry on these three subjects and evaluate their advantages and disadvantages. At the same time the paper will be reviewing the building systems of safety, mechanical, electrical and lighting applicable to this concept and discuss its challenges and effects on the overall design. Overall, this report covers and evaluates research done surrounding this design concept as well as providing topics and information that will need further testing and investigation. Initially, it covers further description of the two design solutions being discussed, skyscraper and earthscrapers, as well as its challenges and future development. The report will follow by an evaluation of the different ways that these designs provide a solution in regards to space scarcity in urban areas, as well as what each requires to be classified as an efficient design. Then, different engineering system implementations in these designs are introduced and a comparison is presented with the most up to date information available in the industry. All this with the purpose to give an idea of the differences in energy efficiency between designs as well as some of the social and psychological effects that these may have on the occupants and community. Finally, an overall evaluation is made in regards to the different benefits and challenges that approaching this new design concept faces, while also providing some recommendations on what could be done within the industry in order to make this possibility a reality.

In this thesis, the finite element method (FEM) is applied to the calculation of frequency-dependent series impedances and shunt capacitances of underground power cables. The principal equations describing the quasi-magnetic fields and static electric fields are solved with FEM based on the Galerkin technique. The Js method and the loss-energy method are derived to calculate the impedances of a multiconductor system from its field solution, and the energy method and the surface charge method are derived to calculate the capacitances. With a single-core (SC) coaxial cable, the suitability of quadratic isoparametric elements and high-order simplex elements are studied, and a suitable division scheme is suggested for the auto-mesh program. The conventional FEM with a field truncation boundary is applied to the impedance calculation of buried SC cables. Suitable locations for the field truncation boundary and division schemes in the earth are studied. The results show that rb ≥ 12[symbol omitted] is required to obtain accurate impedances of shallowly buried cables with the conventional FEM. This requires a large solution region in the earth at low frequencies. A new technique based on the perturbation concept is proposed to reduce the solution region in the earth. Comparisons between the results from the conventional FEM and from the proposed technique with a significantly reduced solution region in the earth show good agreement. In the case studies, the FEM is applied to the parameter calculation of multiphase SC cables, PT cables, sector-shaped cables, and stranded conductors. The numerical results are compared with those from analytical formulas. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

In january 2013, I travelled with my studio to Israel. This project is a collection of what I experienced on our journey through the country, and the thoughts it evoked. It is also a collection of symbols and metaphors found in the areas we visited.   Tel Aviv is widely known as the “White City”. According to the myth, it rose out of the dunes of sand as a new Hebrew city. However, deeper investigation reveals that a part of the municipality is established on the post-Nakba ruins of the former village Manshiya. This village was almost totally erased, partly for political reasons.   The project is an exploration into the story of erasure, and an attempt to evoke the traces of what once was there.  I have proposed an underground structure hidden in sand. The objective is not to present a final answer, but to contribute to an ongoing discussion of who is the winner or loser in the writing of history, and what role architecture has in this battle.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Currently, deficient ventilation systems are a frequently observed problem in mining. Such deficient ventilation systems lead to the recirculation of stale air or air with toxic gases. This translates into an increase in the costs of ventilation and electrical consumption for the mining organizations as conventional and practical solutions simply include options such as buying a greater number of fans. Moreover, this problem also exposes the mine workers to an unsafe work environment with unfavorable conditions that could end in minor, incapacitating, or fatal accidents. Therefore, this research seeks to optimize ventilation systems by introducing the Ventsim software tool to develop efficient coverage, addressing, flow, circuit or network characterization, and air balancing in conjunction with avoiding the stagnation of toxic gases in underground work. The primary result of the proposed model’s application in this study was the reduction in ventilation costs related to electricity consumption.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / The current study is based on a multiple linear regression analysis with an objective to formulate an equation related to the productivity analysis of LHD equipment using independent variables such as the effective utilization of the equipment. To identify the independent variables, main productive factors, such as the actual capacity of the buckets, the transport cycles in the cleaning process, and the performance by means of curves, were analyzed. Comparisons of a Peruvian underground mine case study exhibited that the battery-powered equipment denoted similar production efficiencies to that exhibited by its diesel counterparts; however, the three-tier approach observed that the battery-powered equipment could achieve production efficiencies that are up to 13.8% more as compared to that achieved using its diesel counterparts because of increased effective utilization that can be attributed to long MTBF. The results of this study exhibit that LHDs under battery-powered storage are feasible for underground mining not only because of the fact that they do not emit any polluting gases, which helps to mitigate pollution, but also because of their good production performance that can be considered to be an important pillar in deep mining. Copyright 2019.

>Magister Scientiae - MSc / Three-dimensional (3D) graphic representations of geographic environments have become commonplace in a range of elds. These representations are often an attempt to represent both geographic forms, as well as the relationships that exist between them. In contrast to other elds, the use of 3D geological models in the visualisation of the subsurface environment is relatively new. Additionally, these 3D geological models are traditionally created through the painstaking process of manual development methods. As such, the models developed are unable to fully utilise the wealth of geological data that is collected during subsurface exploration. Therefore, the objective of this research was to create a 3D geological prototype that allowed for the visualisation of underground resource reservoirs in a faster, easier and more aesthetically appealing manner. To achieve the objectives of this research, the problem was tackled holistically by considering both the theoretical and practical components of the research. Some theoretical components that were considered are: well log wireline log data composition, the information that can be extracted from each well log component, geological data interpolation as well as geological visualisation. Utilisation of the theoretical component of this research facilitated the development of a programme that modelled and visualised sub-surface environments. The programme applied the information from numerous well log datasets and interpolated the various geological layers that could be found within a region.

The schlieren technique describes an optical analysis method designed to enhance light distortions caused by air movement. The ability to visualize gas flows has significant implications for analyzing underground mine ventilation systems. Currently, the widely utilized traditional schlieren methods are impractical underground due to complex equipment and design requirements. Background oriented schlieren (BOS) provides a solution to this problem. BOS requires two primary components, a professional quality digital camera and a schlieren background. A schlieren background is composed of a varying contrast repetitive pattern, such as black and white stripes or dots. This background allows the camera's sensor to capture the minor light diffractions that are caused by transparent inhomogeneous gases through image correlation. This paper investigates a possible means of mitigating some of the major problems associated with surveying underground mine ventilation systems with the BOS method. BOS is an imaging technique first introduced in 1999 that allows the visualization of flowing inhomogeneous transparent media. In ventilation surveys, BOS can be used to attain qualitative data about airflows in complex areas and methane emissions from coal. The acquisition of such data would not only enhance the understanding of mine ventilation but also improve the accuracy of ventilation surveys. As an example, surveys can benefit from small scale BOS investigations around fans, regulators, overcasts, and critical junctions to identify effective data gathering positions. Regular inspections of controls and methane monitoring points could also be improved by the systematic nature of BOS. Computer programs could process images of each location identically regardless of quantity. BOS can then serve as a check to identify items that were overlooked during the routine inspection. Despite the potential of BOS for ventilation analysis, several limitations still exist. These issues are sensitivity threshold and quantification of flow data. This paper specifically examines the qualitative potential of the BOS technique for imaging various underground ventilation flows and outlines initial experimental efforts used for the evaluation. Three primary experiments were conducted to evaluate BOS as a potential qualitative analysis technique for underground mine ventilation. The first experiment used BOS to image of flow induced by an axial vane fan and an axial flow fan using an artificial background and an imitation rock background. This experiment showed that the BOS system was unable to image isothermal airflow from either fan. Heated airflow could be visualized with both fans using the artificial striped background but not with the imitation rock background. The BOS system lacked the sensitivity necessary to image isothermal airflow from the two fans. The focus of the overall BOS study was changed to explore higher pressure airflows through a regulator. The second experiment used BOS to image flow through a regulator induced by an axial flow fan using an artificial striped background. The BOS images were compared to ones produced by a traditional schlieren single mirror systems for validation of the BOS experimental design. This experiment was unable to image isothermal airflow through the regulator from either system. However, heated airflow could be visualized by both systems. The BOS and traditional schlieren systems used in this experiment lacked the sensitivity necessary to image isothermal airflow through a regulator. However, the BOS procedures were successfully validated by the ability of both the BOS and traditional schlieren systems to image heated airflows. The focus of the study was changed to explore methane gas emissions. Numerous mining industry techniques already exist to quantify methane content. However, methane content is different from the actual methane emission rate of exposed coal. Emission rates have been modeled using numerical simulation techniques, but the complexity of the methane migration mechanism still requires physical data to achieve higher accuracy. The third experiment investigated the feasibility of using the BOS technique for imaging methane flow by imaging methane emission from a porous medium. Laboratory grade methane was directly injected into a Brea sandstone core sample using a flexible tube. The BOS system was successfully able to image methane desorption in this study. A repeating pattern consisting of alternating black and white stripes served as the schlieren background for the Nikon D700 camera. The ability to image methane emission even at low injection pressures (i.e. 20 psi) demonstrates that actual methane desorption from coal can potentially be imaged. This result can only be conjectured because of a lack of research in the area of methane emission. Despite this issue, the experimental results suggest that BOS can be feasibly utilized to image methane emissions from coal in an underground mine. The results of the three experiment demonstrated that the potential for large scale implementation of BOS in underground mines does exist. Qualitative BOS information has the potential in the practical sense to optimize the procedures of ventilation surveys and design of ventilation monitoring equipment. For example, images of methane flow in active mining areas can be used to optimize the positioning of auxiliary ventilation equipment to dilute known areas of high methane concentration. BOS images could also be used to re-evaluate the placement of methane monitors on mining equipment to better facilitate the detection of dangerous methane concentrations in active mining areas. For these reasons, further investigation into the BOS technique for use in imaging underground airflows with differential temperatures and methane emissions in underground coal mines is suggested as an addendum to this study. / Master of Science

During the 1960s in the United States, AM radio stations began broadcasting an underground format. The purpose of this study is to examine the Beaker Street program on Little Rock's KAAY AM-1090. This show presented non-mainstream programming. Disc jockeys supported alternative points of view, while playing underground music. The 50,000-watt directional AM radio signal at night aired KAAY across the Western Hemisphere. The host, engineer Dale Seidenschwarz, was named Clyde Clifford. Research utilized interviews with Seidenschwarz and KAAY employees. Sources included newspapers, magazine, documents, audio recordings and artifacts. Findings reveal a popular, undocumented radio program. This study tells the significant story of a radio program that people remember and listen to today, now on an FM station.

Underground power cables encounter various problems caused by manufacturing defects and/or environmental contact. In keeping with the Smart Grid vision, researchers must develop diagnostic techniques that can be utilized to facilitate the decision making processes regarding replacement prior to failure can occur, thereby minimizing impact to customers. Due to the impact of the aging infrastructure and in particular underground polymeric cables, various offline and online methods have been developed for the detection of the remaining life of underground cables. The offline methods require power outage, which can lead to further difficulty in their implementation. Signal processing techniques hold promise to provide real time or near real time diagnostics. In this thesis, three different signal processing techniques; fast Fourier transform, short-time Fourier transform, and wavelet transform; are investigated for identifying and classifying various fault types encountered in underground power cables based on cable current and voltage measurements.

<p> The term "underground economy" refers to output that is produced, and income that is generated, by agents who hide this fact from authorities. There has been a recent resurgence in interest in the underground economy and this interest has predominantly been stimulated by the perception that the underground economy is sizeable and growing. This dissertation is comprised of three essays, the goals of which are to provide empirical measures of underground activity.</p> <p> The first paper in this dissertation applies a modeling technique that treats the underground economy as an unobservable or latent variable and incorporates multiple indicator and multiple causal (MIMIC) variables to estimate a time-path of the size of broadly defined underground economy. Using macroeconomic Canadian data, the results indicate that the underground economy grew steadily over the sample period: from 7.5% of Gross Domestic Product (GDP) in 1976 to about 15.3% in 2001.</p> <p> The second paper uses microeconomic data and proposes a nonparametric expenditure-based approach to obtain estimates of income under-reporting by self- employed households. The approach is illustrated by estimating the effect of the Canadian Goods and Services Tax (GST) on income under-reporting. It is found that the difference between true and reported self-employment income is larger for households at the lower end of the self-employment income distribution and that there was no statistically significant change in under-reporting behaviour following the implementation of the GST.</p> <p>The third paper investigates the characteristics of businesses that engage in tax non-compliance using a survey of firms from around the world. Overall, small firms tend to be less compliant than larger firms. In addition, foreign owned firms, exporters, and firms that have audited financial statements are found to be more compliant but quite surprisingly, government ownership does not result in increased tax compliance. Finally, the existence of organized crime, high taxes, and government corruption all result in lower compliance.</p> / Thesis / Doctor of Philosophy (PhD)