Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

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Currently microseismic monitoring is widely used for fracture diagnosis. Since the method monitors the propagation of shear failure events, it is an indirect measure of the propped fracture geometry. Our primary interest is in estimating the orientation and length of the ‘propped’ fractures (not the created fractures), as that is the primary driver for well productivity. This thesis presents a new Low Frequency Electromagnetic Induction (LFEI) method that has the potential to estimate the propped length, height, orientation of hydraulic fractures, and vertical distribution of proppant within the fracture. The proposed technique involves pumping electrically conductive proppant (which is currently available) into the fracture and then using a specially built logging tool to measure the electromagnetic response of the formation. Results are presented for a proposed logging tool that consists of three sets of tri-directional transmitters and receivers at 6, 30 and 60 feet spacing respectively. The solution of Maxwell’s equations shows that it is possible to use the tool to determine both the orientation and the length of the fracture by detecting the location of these particles in the formation after hydraulic fracturing. Results for extensive sensitivity analysis are presented in this thesis to show the effect of different propped lengths, height and orientation of planar fractures in a shale environment. Multiple numerical simulations, using a state-of-the-art electromagnetic simulator (FEKO) indicate, as this work show, that we can detect and map fractures up to 250 feet in length, 0.2 inches wide, and with a 0 to 45 degree of inclination with respect to the wellbore. Special cases such as proppant banking, non-symmetrical bi-wing fractures, and wells with steel casing in place were studied. / text

This study investigates the listening environments of hearing aid users by employing the data logging capacity of their hearing aids. The idea that a hearing aid user's listening environments are important in prescribing desired hearing aid features has been discussed in the literature, however, investigation of listening environments has been limited in the past as it has relied mainly on subjective recordings. Data logging, the capacity of a hearing aid to continuously store information regarding time spent in different programs, listening environments, and microphone modes, is now available in a number of hearing aid models, and therefore provides an objective tool for studying a hearing aid user's listening environments. The data logging information from fifty-seven new hearing aid wearers, including 50 males and 7 females (mean age = 68 years, SD = 11.3), was obtained during the first routine clinic follow-up session for each individual. Measures of time spent in different listening environments, microphone modes, and overall sound levels, were analyzed. Hearing aid usage time was found to be highest in "Speech Only" situations (44.8%), followed by "Quiet" (26.7%), "Noise Only" (16.3%) and "Speech in Noise" (12.3%) situations. The majority of the hearing aid users' time was spent in "Surround" microphone mode (74.3%), followed in order by "Split" (22.3%) and "Full" (3.5%) directional modes. Results of two separate two-way ANOVAs revealed no significant age effect either on time spent in different listening environments [F(3,49) = 0.7, p= 0.5] or on time spent in different microphone modes [F(3,20) = 0.6, p= 0.6]. These findings provide empirical evidence regarding the general listening pattern of hearing aid users, which can be used as a starting point when troubleshooting problems experienced by hearing aid clients, or assessing a user's need for various hearing aid features.

I assessed forest dynamics, stand structure and composition using repeated measurements of permanent plots over twelve years, in areas logged according to RIL guidelines and areas logged conventionally (CL) in Sabah, Malaysia. I compared successful pathways between treatments and used stand dynamics data to estimate carbon fluxes and pools over twelve years. Matrix models were used to generate projections of carbon emissions, sequestration and storage over a thirty-year logging cycle. Stem density (439 stems ha^-1 (95% CI = 358 – 477), basal area (32 m² ha^-1 (95% CI = 23-44) ) and carbon stored in above ground biomass (AGB, 1160 Mg C ha^-1 (95% CI = 97 – 232)) did not differ from prelogging levels twelve years after RIL. There was no recovery of these years variables after CL (246 stems ha^-1 (95% CI = 200 – 303), basal area 20 m² ha^-1 (95% CI = 13-28), carbon in AGB 101 Mg C ha^-1 (95% CI = 58 – 157)). Mortality, growth and recruitment rates remained elevated throughout the study. Both damaged and undamaged trees experiencing high mortality, especially after CL. Stalled, tree-less gaps and vine-covered building phase forest covered 54% of the CL area and appeared to have increased over time. Closed canopy and tree-dominated building phase forest dominated the RIL areas (81%). Total carbon storage over a thirty year logging cycle after RIL is projected to be 40% higher than after CL and result in reduced emissions of 88 Mg C ha^-1 and increased sequestration of 27 Mg C ha^-1. The total carbon benefit of using RIL instead of CL in lowland dipterocarp forest is projected to be 196 Mg C ha^-1 over a cutting cycle. My comparisons and projections of emissions, sequestration and storage in above-ground biomass show that the carbon benefit of reduced-impact logging exceeds previous projections. RIL areas are likely to provide substantial co-benefits in timber stocking, biodiversity conservation and resilience to climate change compared with CL areas.

CEJN is a leading transnational company with long history and professional background providing high-tech quick connect products in global market. The headquarters of the com-pany in Skövde, Sweden, is the birthplace and core location of the entire corporation. In the headquarters, the engineer tests their products at their flow test laboratory. In the laboratory, there are flow test stations for all product ranges. Within them, the most basic are flow test benches for air, water and hydraulic oil products. The flow test benches are aim to test the products under International/Swedish standard conditions to determine the performance. This project is aimed in upgrading the test benches by engineering both hardware and soft-ware, to achieve higher level of automation of the data logging system used in the lab. All three test benches were designed and installed following requirements in corresponding in-ternational standards. The principles of testing are similar, but they are not developed from the same era, and the automation level of each test bench differs. As a result, the need of up-grading in the benches is different. In the laboratory, the recorded test results are reorganized and processed by a report genera-tor developed on Microsoft Excel. The Excel report generator is used for organize test results, calibrate the deviation of the instruments, calculate the flow coefficient of the product, gener-ate performance diagrams of the products, generate test reports for different purpose of use, and save the test data and results on the server of the company. Above all, an upgrade of the data logging system for the three flow test benches was needed. Depending on the conditions of each test bench, the project is implemented and designed the following three parts: • A hardware upgrading (flow rate computer) for the air flow test benchA new signal indicating device for replacing the old flow rate computer is purchased from Italy by the company. The new instrument contains filter function to stabilize the flow rate value. • A software upgrading (Excel report generator) for all the test benchesVisual Basic for Applications (VBA) programming language is used for developing functions such as data communication, signal decoding and user interface developing in Excel. • Develop of an automated data visualizing system for the air flow test benchData communication from the new instrument to a PC through serial port and Mod-bus RTU interface is established. The data visualizing function is compiled in the Ex-cel report generator for the air flow test, realized by VBA programming.

Myths prevail among the general public about wood, forest products, and the condition of the environment in the United States. Research shows that most people are unaware about the proliferation of products that they use in their daily lives that are made out of or are derived from wood, about the amount (and shortcomings) of paper recycling in America, and the degree of environmental "friendliness" that wood and non-wood substitutes inherently possess. Students surveyed on Virginia Tech's campus could not state the main purpose of the United States Forest Service, nor could they identify the primary reason rainforests in South America are disappearing. Survey results from undergraduate students enrolled in the Department of Wood Science and Forest Products showed that they have a much better understanding of the environment and use of wood in people's lives. Survey results from students enrolled in the wood curricula closely parallel those from employees in the wood products industry. An exhaustive literature review of current academic and popular journals is summarized, as are results from the Virginia Tech survey. The impact that public misperceptions have on the wood products industry and steps to remedy them are also examined. Research findings show that the forest products industry needs a coordinated and centralized public promotion campaign to inform the general public about wood's attributes and environmental advantages. / Master of Science

The conservation of biological diversity has become one of the most important goals of managing forests in an ecologically sustainable way. In this thesis, I report a comprehensive study designed to examine the long-term effects of commercial logging and high-intensity fire, and the ability of Population Viability Analysis (PVA) models to predict these effects to aid in the conservation and management of multiple species. Initially, I compared the abundance of small mammals (A. agilis, R. fuscipes, A. swainsonii), and lizards (L. delicata, L. guichenoti, E. heatwolei), in sites with different disturbance histories: 18-19 yearold logging regrowth, 28-29 or 33-34 year???old clearfelling regrowth and unlogged forest. All sites had previously been burnt by bushfires. No evidence of long-term effects of logging or fire was found for A. agilis, R. fuscipes, L. delicata or L. guichenoti, and there were not enough data to make conclusions for A. swainsonii and E. heatwolei. Then the effects of a hazard-reduction burn were investigated. There was variation between the species in the effects of the burn, with interactions between year, aspect and burning for A. agilis and R. fuscipes, and interactions between year, disturbance and topography for the Lampropholis species. A. swainsonii became extremely scarce in the forest after the burn and E. heatwolei were generally unaffected. Next, PVA metapopulation models were used to predict the likely abundance and patch occupancy of these species based on historical data. Retrospective testing showed the models were accurate for all species, but best for A. agilis and R. fuscipes. Lastly, PVA modelling was used to rank management options; no management action, a hazard-reduction burn in 2005 or a logging event in 2005. The models predicted that future management is likely to result in the extinction of A. agilis, R. fuscipes and L. guichenoti by 2010. However, no one management scenario was most detrimental to all species. The current management regime for this forest involves commercial logging on a 40-year cycle and regular hazard-reduction burning. PVA modelling predicts that A. swainsonii and L. delicata are at the greatest risk of extinction under this regime, but that it is also likely to lead to the extinction of A. agilis, R. fuscipes and L. guichenoti in the near future. The results of this research indicate that the conservation of multiple species under one management regime is unlikely to be successful.

Software monitoring and logging is one of the most important tools a software engineer has when faced with the challenge of auditing or analysing a software system. However, the difficulty in effectively monitoring a system, managing its logs and cross referencing them with source code makes software re-engineering a rigorous and complex task. This thesis aims to address this issue by providing a framework that enables pattern matching between a software log and an event pattern expression that is based on a monitoring policy. The framework consists of parsers and annotators that facilitates transformation of a monitoring policy into a Petri Net as well as source code annotation for gathering data through logged events. It further expands upon this work by proposing an adaptive logging framework that will greatly improve the quality of log management by autonomically adjusting the amount of information logged based on the application’s operational environment. Finally, a prototype system of the policy driven monitoring framework is implemented and tested with applications of different scales as a proof of concept for the proposed framework.

The oil and gas industries use sophisticated logging tools during and after drilling. These logging tools employ internal electronics for sensing viscosity, pressure, temperature, and other important quantities. To protect the sensitive electronics, which typically have a maximum allowable temperature of 100 㬠they are shielded and insulated from the harsh external drilling environment. The insulation reduces the external heat input, but it also makes rejection of the heat generated within the electronics challenging. Electronic component failures promoted by elevated temperatures, and thermal stress, require a time consuming and expensive logging tool replacement process. Better thermal management of the electronics in logging tools promises to save oil and gas companies time and money. This research focuses on this critical thermal management challenge. Specifically, this thesis describes the design, fabrication, and test of an innovative thermal management system capable of cooling commercial-off-the-shelf electronics for extended periods in harsh ambient temperatures exceeding 200 㮠Resistive heaters embedded in quad-flat-packages simulate the electronics used in oil well logging. A custom high temperature oven facilitates the evaluation of a full scale prototype of the thermal management system. We anticipate the prototype device will validate computer modeling efforts on which its design was based, and advance future designs of the thermal management system.