Acquisition and maintenance of excellence:the challenges faced by Dutch top-level gymnasts throughout different stages of athletic development

The purpose of the present study is to identify the within-career challenges top-level gymnasts experience during the initiation, development and mastery stage of athletic development in training sessions, competition, and in daily life. In-depth interviews are used to explore the perceived challenges of 16 talented and elite gymnasts (M = 16.5 years, SD = 4.6 years). Participants are divided into three groups, according to the stage of their athletic development. Several challenges are perceived in all stages of athletic development (e.g. learning new elements, dealing with stress under pressure, dealing with distractions and managing their dual career). As the number of different challenges increases as the gymnasts reach the mastery stage, challenges seem to become more personal and specific than in previous stages. The study shows obvious differences in the nature of the perceived challenges for different stages of athletic development, which provides useful insights for those who work with talented and elite athletes

Advanced Oxyfuel Boilers and Process Heaters for Cost Effective CO₂ Capture and Sequestration

This annual technical progress report summarizes the work accomplished during the first year of the program, January-December 2002, in the following task areas: Task 1--Conceptual Design, Task 2--Laboratory Scale Evaluations, Task 3--OTM Development, Task 4--Economic Evaluation and Commercialization Planning and Task 5--Program Management. The program has experienced significant delays due to several factors. The budget has also been significantly under spent. Based on recent technical successes significant future progress is expected. A number of concepts for integrating Oxygen Transport Membranes (OTMs) into boilers and process heaters to facilitate oxy-fuel combustion have been proposed. A detailed modeling plan has been proposed and early modeling work has focused on developing spreadsheet based models for quick engineering calculations. Combustion reactor laboratory scale evaluations efforts have been delayed due to the closing of Praxair's Tarrytown facility in December 2001. Experimental facilities and personnel have been relocated to Praxair's facility in Tonawanda. The facilities have recently been re-commissioned. Work with the OTM development task has also been delayed as early material selections were discarded. More recently, more promising OTM material compositions have been identified. Economic evaluation commenced. Information was acquired that quantified the attractiveness of the advanced oxygen-fired boiler. CO{sub 2} capture and compression are still estimated to be much less than $10/ton carbon

Fundamental study of ash formation and deposition: Effect of reducing stoichiometry. Final report, April 1, 1993--June 30, 1995

The technical objectives of this project are: (1) To identify the partitioning of inorganic coal constituents among vapor, submicron fume, and fly ash products generated during the combustion of pulverized coal under a variety of combustion conditions. Fuel lean and fuel rich combustion conditions are considered. (2) To identify and quantify the fundamental processes by which the transformations of minerals and organically-associated inorganic species occur. Emphasis is placed on identifying any changes that occur as a result of combustion under sub-stoichiometric combustion conditions. (3) To incorporate the effects of combustion stoichiometry into an Engineering Model for Ash Formation

AUTOMATED BUILDING DETECTION USING RANSAC FROM CLASSIFIED LIDAR POINT CLOUD DATA

For the past 10 years, the Philippines has seen and experienced the growing force of different natural disasters and because of this the Philippine governement started an initiative to use LiDAR technology in the forefront of disaster management to mitigate the effects of these natural phenomenons. The study aims to help the initiative by determining the shape, number and distribution and location of buildings within a given vicinity. The study implements a Python script to automate the detection of the different buildings within a given area using a RANSAC Algorithm to process the Classified LiDAR Dataset. Pre-processing is done by clipping the LiDAR data into a sample area. The program starts by using the a Python module to read .LAS files then implements the RANSAC algorithm to detect roof planes from a given set of parameters. The detected planes are intersected and combined by the program to define the roof of a building. Points lying on the detected building are removed from the initial list and the program runs again. A sample area in Pulilan, Bulacan was used. A total of 8 out of 9 buildings in the test area were detected by the program and the difference in area between the generated shapefile and the digitized shapefile were compared

Differences in Walking Pattern during 6-Min Walk Test between Patients with COPD and Healthy Subjects

BACKGROUND: To date, detailed analyses of walking patterns using accelerometers during the 6-min walk test (6MWT) have not been performed in patients with chronic obstructive pulmonary disease (COPD). Therefore, it remains unclear whether and to what extent COPD patients have an altered walking pattern during the 6MWT compared to healthy elderly subjects. METHODOLOGY/PRINCIPAL FINDINGS: 79 COPD patients and 24 healthy elderly subjects performed the 6MWT wearing an accelerometer attached to the trunk. The accelerometer features (walking intensity, cadence, and walking variability) and subject characteristics were assessed and compared between groups. Moreover, associations were sought with 6-min walk distance (6MWD) using multiple ordinary least squares (OLS) regression models. COPD patients walked with a significantly lower walking intensity, lower cadence and increased walking variability compared to healthy subjects. Walking intensity and height were the only two significant determinants of 6MWD in healthy subjects, explaining 85% of the variance in 6MWD. In COPD patients also age, cadence, walking variability measures and their interactions were included were significant determinants of 6MWD (total variance in 6MWD explained: 88%). CONCLUSIONS/SIGNIFICANCE: COPD patients have an altered walking pattern during 6MWT compared to healthy subjects. These differences in walking pattern partially explain the lower 6MWD in patients with COPD

The partitioning of iron during the combustion of pulverized coal.

The presence of pyrite in coal has long been known to affect the slagging propensity of the coal when burned in industrial boilers. In particular it has been found that molten pyrite bonds very well to steel furnace tubes. In addition, it has been found that the amount of chemically bound iron greatly influences the slag contact angle and stickiness on steel heat transfer tubes. The goal of this research, which is part of a larger project headed by the PSI Technology Company to study mineral matter transformations during combustion, is to explore and model the mechanisms dominating the fate of iron during combustion. To achieve this goal a well characterized suite of coals was burned in a 17kW downfired laboratory combustor. Fly ash was extracted from the flue gas and size classified. These ash samples were then subjected to a number of analytical techniques including Atomic Absorption Spectroscopy (AA), Energy Dispersive X-Ray (EDX), Computer Controlled Scanning Electron Microscopy (CCSEM), Transmission Electron Microscopy (TEM), and Mossbauer Spectroscopy to determine the ash bulk composition and morphology. Of these techniques, Transmission Electron Microscopy and Mossbauer, were instrumental in determining the iron-silicate interactions during combustion. Utilizing the information gleaned from the fly ash analysis, and work in the literature, it was possible to propose a pathway for iron interactions during combustion. A mechanistic model was then proposed to quantify the competition between processes governing iron oxidation/crystallization and those promoting iron-silicate mixing/reaction. This model described the partitioning of iron between chemically bound and physically bound phases. By utilizing kinetic parameters from the literature and fundamental transport phenomena, this model was able to successfully correlate data from several coals burned under a range of combustion conditions. The model can also be used to quantify the effect of combustion modifications and fuel property changes on iron partitioning

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

Conventional wisdom says adding oxygen to a combustion system enhances product throughput, system efficiency, and, unless special care is taken, increases NOx emissions. This increase in NOx emissions is typically due to elevated flame temperatures associated with oxygen use leading to added thermal NOx formation. Innovative low flame temperature oxy-fuel burner designs have been developed and commercialized to minimize both thermal and fuel NOx formation for gas and oil fired industrial furnaces. To be effective these systems require close to 100% oxy-fuel combustion and the cost of oxygen is paid for by fuel savings and other benefits. For applications to coal-fired utility boilers at the current cost of oxygen, however, it is not economically feasible to use 100% oxygen for NOx control. In spite of this conventional wisdom, Praxair and its team members, in partnership with the US Department of Energy National Energy Technology Laboratory, have developed a novel way to use oxygen to reduce NOx emissions without resorting to complete oxy-fuel conversion. In this concept oxygen is added to the combustion process to enhance operation of a low NOx combustion system. Only a small fraction of combustion air is replaced with oxygen in the process. By selectively adding oxygen to a low NOx combustion system it is possible to reduce NOx emissions from nitrogen-containing fuels, including pulverized coal, while improving combustion characteristics such as unburned carbon. A combination of experimental work and modeling was used to define how well oxygen enhanced combustion could reduce NOx emissions. The results of this work suggest that small amounts of oxygen replacement can reduce the NOx emissions as compared to the air-alone system. NOx emissions significantly below 0.15 lbs/MMBtu were measured. Oxygen addition was also shown to reduce carbon in ash. Comparison of the costs of using oxygen for NOx control against competing technologies, such as SCR, show that this concept offers substantial savings over SCR and is an economically attractive alternative to purchasing NOx credits or installing other conventional technologies. In conjunction with the development of oxygen based low NOx technology, Praxair also worked on developing the economically enhancing oxygen transport membrane (OTM) technology which is ideally suited for integration with combustion systems to achieve further significant cost reductions and efficiency improvements. This OTM oxygen production technology is based on ceramic mixed conductor membranes that operate at high temperatures and can be operated in a pressure driven mode to separate oxygen with infinite selectivity and high flux. An OTM material was selected and characterized. OTM elements were successfully fabricated. A single tube OTM reactor was designed and assembled. Testing of dense OTM elements was conducted with promising oxygen flux results of 100% of target flux. However, based on current natural gas prices and stand-alone air separation processes, ceramic membranes do not offer an economic advantage for this application. Under a different DOE-NETL Cooperative Agreement, Praxair is continuing to develop oxygen transport membranes for the Advanced Boiler where the economics appear more attractive

Oxygen Enhanced Combustion for NOx Control

Conventional wisdom says adding oxygen to a combustion system enhances product throughput, system efficiency, and, unless special care is taken, increases NOx emissions. This increase in NOx emissions is typically due to elevated flame temperatures associated with oxygen use leading to added thermal NOx formation. Innovative low flame temperature oxy-fuel burner designs have been developed and commercialized to minimize both thermal and fuel NOx formation for gas and oil fired industrial furnaces. To be effective these systems require close to 100% oxy-fuel combustion and the cost of oxygen is paid for by fuel savings and other benefits. For applications to coal-fired utility boilers at the current cost of oxygen, however, it is not economically feasible to use 100% oxygen for NOx control. In spite of this conventional wisdom, Praxair and its team members, in partnership with the US Department of Energy National Energy Technology Laboratory, have developed a novel way to use oxygen to reduce NOx emissions without resorting to complete oxy-fuel conversion. In this concept oxygen is added to the combustion process to enhance operation of a low NOx combustion system. Only a small fraction of combustion air is replaced with oxygen in the process. By selectively adding oxygen to a low NOx combustion system it is possible to reduce NOx emissions from nitrogen-containing fuels, including pulverized coal, while improving combustion characteristics such as unburned carbon. A combination of experimental work and modeling was used to define how well oxygen enhanced combustion could reduce NOx emissions. The results of this work suggest that small amounts of oxygen replacement can reduce the NOx emissions as compared to the air-alone system. NOx emissions significantly below 0.15 lbs/MMBtu were measured. Oxygen addition was also shown to reduce carbon in ash. Comparison of the costs of using oxygen for NOx control against competing technologies, such as SCR, show that this concept offers substantial savings over SCR and is an economically attractive alternative to purchasing NOx credits or installing other conventional technologies. In conjunction with the development of oxygen based low NOx technology, Praxair also worked on developing the economically enhancing oxygen transport membrane (OTM) technology which is ideally suited for integration with combustion systems to achieve further significant cost reductions and efficiency improvements. This OTM oxygen production technology is based on ceramic mixed conductor membranes that operate at high temperatures and can be operated in a pressure driven mode to separate oxygen with infinite selectivity and high flux. An OTM material was selected and characterized. OTM elements were successfully fabricated. A single tube OTM reactor was designed and assembled. Testing of dense OTM elements was conducted with promising oxygen flux results of 100% of target flux. However, based on current natural gas prices and stand-alone air separation processes, ceramic membranes do not offer an economic advantage for this application. Under a different DOE-NETL Cooperative Agreement, Praxair is continuing to develop oxygen transport membranes for the Advanced Boiler where the economics appear more attractive