71 |
Study of analysis and improvement methods on running breakdown for the table rollers of hot rolling strip cooling area.Li, Hsin-pao 10 September 2006 (has links)
The rollers of run out table in Hot Strip Mill are operated with variable high rotational speed under a severe environment of high temperature and much cooling water around. And the table takes long space about 128 meters of length with over 330 rollers. The rollers of this area often break down, and it takes long to make urgent repair. So it costs about ten million NT dollars per year for mill shut-down. Although some improvements have been made before, the troubles still happens frequently. Then the temporary countermeasures of shortening the maintenance cycle and increasing the grease supply have been applied to prevent the break-down frequency from aggravation . But it wastes the cost and does not meet the environmental policy.
This study analyzes many damage phenomena. Then it assumes that the 75% of roller running break-down is bearing damage resulting from bad lubrication condition and abnormal axial load. The cooling water which penetrates into bearing housing will result in grease emulsification and its consistency diluting. This certainly causes the bad lubrication condition and bearing rusting. In the meantime, if the floating function of roller bearing is inactive, the bearings will be operated under abnormal high axial load and without appropriate lubrication. Then the bearing will be damaged rapidly and must be repaired quickly.
In order to improve bad lubrication and bearing rusting, this study modifies sealing arrangement and grease feeding circuit for bearing housing with the special functions of water obstruction, drainage and resistance to prevent water penetration. In addition, the overflow of grease will be collected to meet the environmental needs. Meanwhile, to look for better water resistance and mechanical stability for greasing, the study also discusses the relationship between consistency variation and thickening soap base after grease emulsification. During a three-month running of the new design , the water contents are stably under 1.5% which has greatly advanced. And the quantity of grease supply is under 10% of existing one.
In order to improve the inactive floating function of roller bearings, this study not only analyzes the derivation of problems but also modifies the dimensional tolerance and adds cylindricity of geometric tolerance for the bore of bearing housing. This will ensure complete loose fit and shape accuracy to prevent the interference fit between the bore and bearing caused by manufacturing inaccuracy or other mistakes
|
72 |
A Run-Time Loop Parallelization Technique on Shared-Memory Multiprocessor SystemsWu, Chi-Fan 06 July 2000 (has links)
High performance computing power is important for the current advanced calculations of scientific applications. A multiprocessor system obtains its high performance from the fact that some computations can proceed in parallel. A parallelizing compiler can take a sequential program as input and automatically translate it into parallel form for the target multiprocessor system. But when loops with arrays of irregular, nonlinear or dynamic access patterns, no any current parallelizing compiler can determine whether data dependences exist at compile-time. Thus a run-time parallel algorithm will be utilized to determine dependences and extract the potential parallelism of loops. In this thesis, we propose an efficient run-time parallelization technique to compute a proper parallel execution schedule in those loops. This new method first detects immediate predecessor iterations of each loop iteration and constructs an immediate predecessor table, then efficiently schedules the whole loop iterations into wavefronts for parallel execution. According to either theoretical analysis or experimental results, our new run-time parallelization technique reveals high speedup and low processing overhead. Furthermore, this new technique is appropriate to implement on multiprocessor systems due to the characteristics of high scalability.
|
73 |
The Earnings Management During SEO of Public Companies in TaiwanOu-Yang, Tah-der 06 June 2002 (has links)
While improving the seasoned equity offerings, companies often manipulate the earnings or window the financial statements to get approval and increase IPO prices, and thus acquiring the funds easier. The main focus for this study is to exam whether the firms listed in Taiwan Stock Exchange manipulate earnings through discretionary accruals before the seasoned equity offerings, and the relationship between pre-issue discretionary accruals and the post-issue earnings, operating performance and long-term stock returns. The sample observed consists of 226 firms listed in Taiwan Stock Exchange conducting seasoned equity offering from 1991 to 1998 and the Modified Jones Model was used to estimate the discretionary accruals basing on the financial statements of the year. The discretionary accruals are the main research variables. The empirical results show that: 1. Firms listed in Taiwan Stock Exchange intend to manipulate the discretionary current accruals before conducting the seasoned equity offerings in order to improve earnings, and the larger pre-issue discretionary accruals, the larger the decline of post-issue earnings. 2. The post-issue total asset returns are clearly negatively correlated to the discretionary current accruals in the year before the seasoned equity offerings, indicating that the adjustment of discretionary accruals will influence the post-issue operating performance. 3. Excluding the possible influences from the industry, the discretionary current accruals present significantly negative effect on the post-issue operating performance. The level of earnings management becomes larger, the post-issue long-term stock return will decline greater.
|
74 |
Test-retest reliability of the 300-yard Shuttle Run TestGottlieb, Hanna January 2015 (has links)
Background: Several field-based team sports contain repeated, maximal effort sprints with varying rest lengths in between. This puts high demands on athletes’ metabolic and neuromuscular systems. Testing the anaerobic capacity of athletes is essential to improve and evaluate the progression. One test being utilised for assessing anaerobic capacity is the 300-yard shuttle run test. The test is field-based with stopwatches as the sole equipment. However, the test has not been properly tested for reliability. Aim: The aim of this bachelor thesis was therefore to investigate the reliability of the 300-yard shuttle run test. Methods: The study was performed with a test-retest method and included a familiarisation meeting, test session and retest session. Test subjects performed the 300-yard shuttle run test at two different occasions with seven or fourteen days in between. The intraclass correlation coefficient (ICC) and 95% confidence interval (CI) was utilised to quantify the reliability. An ICC>0.8 was considered acceptable. Results: 17 American football players participated in the study (median age 20, min. =18, max. =38 y; median weight 83, min. =67, max. =133 kg; median height 184, min. =169, max. =194 cm). The ICC for the test-retest was 0.97 (95% CI 0.91-0.99). Conclusion: Based on the results of this study 300-yard shuttle test is proposed as a test providing reliable results.
|
75 |
A morphometric analysis of the geomorphology of Florida's springsWalker, Andrew Curtis 01 June 2006 (has links)
An exploratory study of the geomorphology of Florida's springs was conducted using morphometric analysis. Spatial datasets for spring locations, elevation data, physiography, geology and hydrography were acquired for incorporation and analysis with GIS technology. ArcGIS 9 was used to measure certain morphometric parameters from the spatial data for Florida's springs. Other Parameters representing physical and dimensional characteristics of the springs were acquired from FGS Bulletin 66, Springs of Florida. All measured and collected data was compiled into a usable morphometric database. The data is described statistically and summarized according to the spatial distribution of Florida's springs with respect to geology and landforms. This examination is carried out at two different scales; 1) the entire population of Florida's 754 springs is examined with emphasis placed upon geology, physiography, and elevation, 2) a subset of 102 springs that is deemed to be a representative sample is examined according to all morphometric parameters. It was concluded that the presence of karst terrain at the majority of the spring sites that were examined in this study is the prevailing factor that has influenced where springs have resurged in Florida. This was observed at both scales in the study. It is also concluded that spring sites in Florida are strongly linked to lower elevations, and therefore that elevation also influences their distribution. Suggestions for future research are posed, including specific ways in which the current methodology can be expanded upon and improved.
|
76 |
Long run changes in driver behavior due to variable tollsKonduru, Karun K. 30 September 2004 (has links)
As many variable pricing projects are still in the implementation stage, long-run driver responses to the variable tolls are largely unknown. This research examined the long-run changes in driver behavior in an existing variable pricing project in Lee County, Florida. Using empirical evidence, it was found that over time the price elasticities of demand on the Lee County toll bridges have decreased from -0.42 to -
0.11 (Midpoint Memorial Bridge) and from -0.31 to -0.06 (Cape Coral Bridge) during the early morning discount period. The elasticities have decreased, but to a lesser extent, during the late morning and early afternoon discount periods. A discount period volume spreading ratio was also developed to analyze these changes. The results from this analysis confirmed the elasticity results. In addition to the empirical analysis of travel patterns discussed above, a telephone survey of drivers was conducted. The survey results indicated that certain driver characteristics such as higher frequency of trips, commute trip purpose, full-time employment status, more people in the household, higher education, and age between 25-34 years, were all indicators that the participant may increase his or her variable pricing usage over time. Other characteristics, including being retired and having a household income less than $16,000, were indicators that the driver may not increase variable pricing participation. Binary logit and semiparametric models were also developed to examine socio-economic and commute characteristics that may influence a driver increasing his or her participation in a variable pricing program. The results from these two variable toll bridges in Lee County indicated a decrease in variable toll price elasticity over time. However, these results may not be typical for variable pricing projects. Factors such as alternative routes, different traveler demographics, traffic congestion levels, and size of the toll discount may influence the results obtained from other variable pricing projects. However, the methodology developed in this research can be applied to other projects in order to determine those toll price elasticities of demand.
|
77 |
Physical fitness, body composition and pedometer measured physical activity in children in a rural Manitoba communityKozera, Tanya R. 21 September 2007 (has links)
A child’s level of physical activity is an important component of that child’s health. Our understanding of physical activity patterns in children is limited in rural settings, and virtually absent for climates with snow cover. Opportunities for physical activity intervention need to be identified. PURPOSE: Investigation of the relationships between pedometer-measured physical activity, body composition and aerobic performance in rural children in the winter and examination of within-day variation in stepping behavior using interval pedometry. METHODS: Aerobic performance (20 m shuttle run) with “talk test” validation and body composition (BMI, BF) were measured during mid-winter during the school year in 8 to 10 year old children. Pedometer step counts were recorded at 6 intervals throughout the day for 7 days. RESULTS: Fifty-six subjects (22 males and 34 females, mean age 9.09 (0.49), had the following measurements; BMI 17.9 (3.3), BF% 24.3 (9.5) (tricep/calf), 10,465 (±2506) steps/day, VO2 45.12 ml/kg/min (±2.87), shuttle run stage 3.0 (±1.34). Weekday steps/day (11,422 ±2573) were greater than weekend (8,112, ±3499) steps/day for both boys and girls (p<0.01). Town children recorded 1800 more steps/day than out of town children (p<0.01). All measures of body composition were found to be significantly related to aerobic power (p<0.01). Weekday steps were related to aerobic performance. The fittest (upper 1/3) children were leaner and had more afternoon school steps, and higher afternoon school step rates. CONCLUSION: Daily step counts were 2000-4000 steps lower than other studies and may be an impact of winter in Manitoba or the rural setting. This was consistent with overall low aerobic performance and higher adiposity of the children. Interval pedometry was capable of identifying differences in activity patterns between most and least fit children in rural Manitoba providing for targeted intervention strategies.
|
78 |
Physical fitness, body composition and pedometer measured physical activity in children in a rural Manitoba communityKozera, Tanya R. 21 September 2007 (has links)
A child’s level of physical activity is an important component of that child’s health. Our understanding of physical activity patterns in children is limited in rural settings, and virtually absent for climates with snow cover. Opportunities for physical activity intervention need to be identified. PURPOSE: Investigation of the relationships between pedometer-measured physical activity, body composition and aerobic performance in rural children in the winter and examination of within-day variation in stepping behavior using interval pedometry. METHODS: Aerobic performance (20 m shuttle run) with “talk test” validation and body composition (BMI, BF) were measured during mid-winter during the school year in 8 to 10 year old children. Pedometer step counts were recorded at 6 intervals throughout the day for 7 days. RESULTS: Fifty-six subjects (22 males and 34 females, mean age 9.09 (0.49), had the following measurements; BMI 17.9 (3.3), BF% 24.3 (9.5) (tricep/calf), 10,465 (±2506) steps/day, VO2 45.12 ml/kg/min (±2.87), shuttle run stage 3.0 (±1.34). Weekday steps/day (11,422 ±2573) were greater than weekend (8,112, ±3499) steps/day for both boys and girls (p<0.01). Town children recorded 1800 more steps/day than out of town children (p<0.01). All measures of body composition were found to be significantly related to aerobic power (p<0.01). Weekday steps were related to aerobic performance. The fittest (upper 1/3) children were leaner and had more afternoon school steps, and higher afternoon school step rates. CONCLUSION: Daily step counts were 2000-4000 steps lower than other studies and may be an impact of winter in Manitoba or the rural setting. This was consistent with overall low aerobic performance and higher adiposity of the children. Interval pedometry was capable of identifying differences in activity patterns between most and least fit children in rural Manitoba providing for targeted intervention strategies.
|
79 |
Laboratory-scale investigations of stormwater treatment in the Lake Tahoe Basin using chemical coagulantsCurtis, Jeffry G. January 2007 (has links)
Thesis (Ph. D.)--University of Nevada, Reno, 2007. / "May, 2007." Includes bibliographical references. Online version available on the World Wide Web.
|
80 |
A 15-year research summary and hunting harvest data evaluation of the Broad Run Management Area /Weekes, William Dickey, January 1974 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute. / Vita. Includes bibliographical references (leaves 196-201). Also available via the Internet.
|
Page generated in 0.081 seconds