• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3539
  • 1657
  • 509
  • 451
  • 343
  • 262
  • 130
  • 82
  • 67
  • 53
  • 47
  • 47
  • 47
  • 47
  • 47
  • Tagged with
  • 8733
  • 1437
  • 1276
  • 1269
  • 854
  • 595
  • 565
  • 522
  • 475
  • 395
  • 390
  • 355
  • 340
  • 331
  • 308
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

On the relationship between winter storms, strong winds, and the associated pressure field along a rugged western coast

McDonough, Thomas Andrew 21 September 1976 (has links)
Two successive years of wind speed and direction data, from January 1973 through December 1974, have been measured and recorded at Yaquina Head, 6 km north of Newport, Oregon. Analysis of the data permitted 65 cases of strong wind to be isolated and separated into four distinct wind speed categories. With the aid of surface charts, upper air sounding, and sea level pressures from several stations, numerous meteorological events, occurring concurrently with peak winds at Yaquina Head, have been evaluated for a significant contribution to the local wind. Cyclone centers associated with strong coastal wind have been plotted and analyzed with regard to location, speed and direction of motion, sea surface pressure, and pressure change during periods of strong winds. The result of this analysis indicates that many cases of strong coastal wind measured at Yaquina Head are associated with cyclones located southwest of Vancouver Island, British Columbia. The pressure change experienced by these cyclones is related to the strength of the observed wind at Yaquina Head. Likewise, the locations of these pressure centers are related to the duration of strong wind measured at Yaquina Head. The direction of motion of the cyclones and the value of the sea surface pressure at the center of the cyclones seem unrelated to local wind speed. Frontal zones associated with cases of strong wind have been evaluated with regard to type, speed, and direction of motion prior to strong surface winds. No relationship was found between these factors and the strength of the wind. The direction of the wind versus the speed of the wind was reviewed and the results were separated into several classes. The result of this classification indicated that in 73 percent of the cases the measured peak wind occurred prior to an abrupt veering of the wind. Only 21 percent of the cases lacked this wind shift. The local pressure field was examined for pressure differences which might result in a strong coastal wind flow. Station pressures from three locations were used as well as barograms from Newport, Oregon, in describing the pressure field. No correlation between these pressures differences and the strength of the local wind could be found. Finally, the north-south component of the geostrophic wind was calculated and compared with speed of the measured wind. No consistent agreement could be established between the measured surface wind speed and the calculated north- south component of the geostrophic wind. The lack of data west of Yaquina Head and Oregon Coast continue to present a problem for those who consider coastal winds. / Graduation date: 1977
12

Pressure transient test analysis of vuggy naturally fractured carbonate reservoir: field case study

Ajayi, Babatunde Tolulope 02 June 2009 (has links)
Well pressure transient analysis is widely used in reservoir management to obtain reservoir information needed for reservoir simulation, damage identification, well optimization and stimulation evaluation. The main objective of this project is to analyze, interpret and categorize the pressure transient responses obtained from 22 wells in a vuggy naturally fractured carbonate reservoir in an attempt to understand the heterogeneities of the porosity system. Different modeling techniques useful in simulating well behavior in vuggy naturally fractured reservoirs were developed and categorized. The research focused on pressure transient analysis using homogeneous, radial composite, single fracture, dual porosity and triple porosity reservoir models along with conventional boundary models which show boundary limits including single and double sealing boundary, closure and constant pressure boundary. A triple porosity model was developed, and it proved to be very effective for use in the analysis of the pressure responses obtained from this field. For some wells, the need for new models to characterize the pressure responses in more complex reservoirs was highlighted as conventional models failed.
13

Factors associated with perceived time pressure among Canadian working parents : does gender make a difference?

Fitzpatrick, Terrie 07 September 2011
The perception of not having enough time to do all of the things one needs to get done appears to be on the rise across industrialized nations. In Canada, for example, 16.4% of the population reported high levels of pressure in 1992, compared with 19.7% in 2005. Understanding the factors associated with perceived time pressure is important for public health, particularly given research suggesting that perceptions of time pressure are increasing in Western society and that such perceptions are linked with social and mental well-being. The overall goal of this study was to better understand the patterning of perceived time pressure among working mothers and fathers in Canada according to whether they occupied the additional role of partner and/or caregiver, as well as according to characteristics associated with their paid work and family roles. The Gender, Work, and Family Health Survey, conducted in Saskatoon Canada in 2005 provided the data for this study. The total sample was 1160 (674 women and 486 men). Results of the multiple linear regression analyses showed that both role occupancy and role quality were related to perceived time pressure among employed parents but that the precise nature of these relationships depends on gender. For mothers, the following factors were associated with increased time pressure: occupancy of an unpaid caregiving role, parenting a child with at least one health/behavioral problem, agreement with the statements <i>"parenting makes me feel drained or exhausted"</i> or <i>"parenting makes me feel tense and anxious"</i>, and low perceived social support. Regarding the paid work environment, women who were categorized as high strain (ie., high demands/low control) or active (high demands/high control) also reported higher levels of time pressure. For fathers, the following variables were associated with greater time pressure: occupancy of the partner role, being a multiple job holder and having a high strain (ie., high demands/low control) or active (high demands/high control) psychosocial work environment. Limitations of the study are discussed as are the policy implications of the findings.
14

The swimming response of the Sacconereis stage of Autolytus varius to changes in hydrostatic pressure

Smith, Randall William 09 May 1969 (has links)
The syllid polychaete Autolytus varius reproduces in the spring and early summer in Yaquina Bay, Oregon, The fertilized female epitokes, or Sacconereis, carry the developing eggs and larvae in a ventral sac until the larvae are ready to be released; incubation lasts 14 to 18 days in the laboratory, The effects of a small increase in hydrostatic pressure on the activity of Sacconereis were tested, When placed in a pressure vessel, these epitokes responded to increases of 0.39 Bar by orienting dorsally and swimming upward, and by increasing their swimming rate, Peak activity occurred in the first minute after a pressure stimulus. Following this, there was a period of accommodation until the epitokes returned close to their normal level of activity; the period of accomodation lasted around 11 minutes, When the pressure was released, the worms either slowed their swimming rate, or they coiled and sank rapidly to the bottom of the vessel. Decerebrate Sacconereis of A. varius did not respond to pressure stimuli. The Sacconereis of A. magnus and A. prismaticus, and the Polybostrichus of A. prismaticus demonstrated swimming responses similar to A. varius Sacconereis. Three other species of polychaetes did not respond to pressure changes. The hydrostatic pressure response is possibly an adaptation of a planktonic stage of a normally benthic animal. / Graduation date: 1969
15

Factors associated with perceived time pressure among Canadian working parents : does gender make a difference?

Fitzpatrick, Terrie 07 September 2011 (has links)
The perception of not having enough time to do all of the things one needs to get done appears to be on the rise across industrialized nations. In Canada, for example, 16.4% of the population reported high levels of pressure in 1992, compared with 19.7% in 2005. Understanding the factors associated with perceived time pressure is important for public health, particularly given research suggesting that perceptions of time pressure are increasing in Western society and that such perceptions are linked with social and mental well-being. The overall goal of this study was to better understand the patterning of perceived time pressure among working mothers and fathers in Canada according to whether they occupied the additional role of partner and/or caregiver, as well as according to characteristics associated with their paid work and family roles. The Gender, Work, and Family Health Survey, conducted in Saskatoon Canada in 2005 provided the data for this study. The total sample was 1160 (674 women and 486 men). Results of the multiple linear regression analyses showed that both role occupancy and role quality were related to perceived time pressure among employed parents but that the precise nature of these relationships depends on gender. For mothers, the following factors were associated with increased time pressure: occupancy of an unpaid caregiving role, parenting a child with at least one health/behavioral problem, agreement with the statements <i>"parenting makes me feel drained or exhausted"</i> or <i>"parenting makes me feel tense and anxious"</i>, and low perceived social support. Regarding the paid work environment, women who were categorized as high strain (ie., high demands/low control) or active (high demands/high control) also reported higher levels of time pressure. For fathers, the following variables were associated with greater time pressure: occupancy of the partner role, being a multiple job holder and having a high strain (ie., high demands/low control) or active (high demands/high control) psychosocial work environment. Limitations of the study are discussed as are the policy implications of the findings.
16

Pressure transient test analysis of vuggy naturally fractured carbonate reservoir: field case study

Ajayi, Babatunde Tolulope 02 June 2009 (has links)
Well pressure transient analysis is widely used in reservoir management to obtain reservoir information needed for reservoir simulation, damage identification, well optimization and stimulation evaluation. The main objective of this project is to analyze, interpret and categorize the pressure transient responses obtained from 22 wells in a vuggy naturally fractured carbonate reservoir in an attempt to understand the heterogeneities of the porosity system. Different modeling techniques useful in simulating well behavior in vuggy naturally fractured reservoirs were developed and categorized. The research focused on pressure transient analysis using homogeneous, radial composite, single fracture, dual porosity and triple porosity reservoir models along with conventional boundary models which show boundary limits including single and double sealing boundary, closure and constant pressure boundary. A triple porosity model was developed, and it proved to be very effective for use in the analysis of the pressure responses obtained from this field. For some wells, the need for new models to characterize the pressure responses in more complex reservoirs was highlighted as conventional models failed.
17

The effects of barometric pressure on elementary school students' behavior

Staut, Aaron J. January 2001 (has links) (PDF)
Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2001. / Includes bibliographical references.
18

The vapor pressure of solid argon, carbon monoxide, methane, nitrogen, and oxygen from their triple points to the boiling point of hydrogen

Wylie, Leonard Mills 12 1900 (has links)
No description available.
19

Heat transfer and velocity measurements in a kettle reboiler

Miller, Keith Martin January 2000 (has links)
No description available.
20

Rock fabric analysis : a new approach to mine planning.

Blair, Paul Martin. January 1969 (has links)
No description available.

Page generated in 0.0489 seconds