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A Study To Determine Necessity of Pilot Holes When Drilling Shallow Gas Zones Using Top Hole Dual Gradient Drilling TechnologyKing, Lauren 16 January 2010 (has links)
When drilling offshore, shallow gas hazards are a major concern because of their
potential to cause a major blowout. This is a special concern when drilling in shallower
water, where the gas influx reaches the rig sooner. A common practice used to avoid the
potential dangers of shallow gas is to drill a pilot hole through the shallow gas zone with
the hope that the smaller diameter hole will prevent such a large influx. The use of dual-gradient
top hole drilling technology would allow for a larger hole to be drilled and the
possible gas influx to be killed dynamically, which I have simulated with the use of a
top hole dual-gradient simulator.
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An evaluation of subsea pump technologies that can be used to achieve dual gradient drillingOluwadairo, Tolulope 15 May 2009 (has links)
Dual Gradient Drilling is an exciting technology which promises to solve the current
technical hurdles and economic risks of Deepwater Drilling. Several techniques for Dual
Gradient Drilling have been proposed to the industry. One such method involves
installing a subsea booster pump at the seafloor with the aim of returning the drilling
fluid back to the rig. The pump will manage annular pressures in the wellbore as
circulation rates and mud weights vary and will permit early detection of wellbore
influxes. Any such pump chosen to achieve this objective will be subjected to very high
differential pressures and will be faced with the onerous task of lifting very abrasive and
viscous mud slurries from the sea floor back to the drilling rig. This distance in deep
water may be well within the range of about 4, 000 – 12,000 feet depending on the
operating water depth of the rig.
Several pump technologies available to the industry were examined. Piston pumps are
very efficient and can withstand the high differential pressures encountered in the
Mudlift Drilling System. However, their drawbacks are their large size and weight and
high initial capital cost and maintenance costs. Centrifugal pumps on the other hand are relatively smaller than piston and diaphragm pumps and are generally less expensive.
Disc pumps, with their non-impingement design are able to handle solids and fluids with
a high gas volume fraction but, like centrifugal pumps, are generally less efficient than
reciprocating pumps. Diaphragm pumps are capable of maintaining a constant rate
regardless of pressure fluctuations. They can handle very abrasive solids with limited
wear on the pump. They also excel at handling very viscous fluids and they can be
modified to handle up to 95% gas volume fraction. Like piston pumps, they have very
high efficiencies.
The potential of each of these pump technologies to meet the requirements for the
Mudlift Drilling System was examined in this thesis. The benefits and drawbacks of
each of these pump technologies were highlighted and modifications to meet the
demands of the mudlift system evaluated.
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Dual Coding Theory and Chinese: Recall of Concrete and Abstract Sentences in Chinese-English BilingualsChen, Tsuei-Fen 2010 August 1900 (has links)
Theories of reading have seldom been examined across orthographies. In the
present study, Dual Coding Theory (DCT), a general theory of cognition applied to
literacy, was applied to Chinese sentences to investigate the effects of language
concreteness and abstractness on immediate recall. Forty Chinese-English bilinguals
read and recalled five concrete sentences and five matched abstract sentences. Of the ten
sentences, five were English, and five were Chinese. Due to the characteristics of
Chinese orthography, Chinese script may have a direct and more efficient access to
meaning; hence, it is possible that concrete sentences in Chinese would not have the
typical advantage over abstract sentences in recall found in other languages. However,
the results showed that concrete Chinese sentences were recalled better than abstract
Chinese sentences. A 2 (languages: Chinese vs. English) x 2 (sentence concreteness:
concrete vs. abstract) analysis of variance with proportion of recall as the dependent
variable showed that significant main effects were found for languages, F (1, 76) =11.68, p = .001, n2 = .13, and for concreteness, F (1, 76) = 38.12, p < .001, n2 = 33. That is,
Chinese was overall recalled significantly better than English, and concrete sentences
were overall recalled significantly better than abstract sentences. There was no
significant interaction. Concrete Chinese sentences were recalled 1.32 times as much as
abstract Chinese sentences, thus confirming the concreteness effects in Chinese. The
results of the study are consistent with those of previous studies on DCT in alphabetic
languages, and they also provide evidence of concreteness effects across orthographies.
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Design of Stripline-Fed Dual Polarization Aperture-Coupled Stacked Microstrip Patch Phased Array Antenna for Wideband ApplicationKim, David G. 2010 August 1900 (has links)
Recent days, antennas play an important role in wireless communication system. Microstrip
patch antennas are well known to have positive features for cost-effective, low profile and
broadband. This type of antenna can be used in wide range of applications such as in wireless
communications, radar systems, and satellites. Inhibiting characteristics of single patch antenna
with low gain and narrow band leads to the research area to have array configuration. Beam
steering antennas are the ideal solution for various systems such as traffic control and collision
avoidance radar systems.
The goal of this work is to design and implement a dual-linear polarization stacked microstrip
patch phased array antenna. Single stacked microstrip patch antenna fed by microstrip line was
designed to have approximately 3 GHz bandwidth in X-band with another ground plane to form
a stripline-fed. Stripline-fed design protects feed lines from any outside effects. The array
configuration was adapted to design in order to accomplish beam scan angle of /- 30 degrees by /- 15 degrees.
Binomial power distribution of 3x2 array structure was used in order to reduce grating lobes, and
changing length of feed lines was implemented for phase shifting. Bowtie cross shape aperture
and dual-offset microstrip feedline was used to feed radiating patches. For the feed network, T-split power divider was implemented and optimized to achieve low loss. The length of microstrip
line was adjusted to meet desired phase shift that in wideband application, the length of the line
had to be long enough to have similar wavelength response over broad frequency range. The
antenna array was designed using standard equations and simulated by electromagnetic analysis
software called Zealand's IE3D which is method-of-moments based simulator. The resulting
measured impedance bandwidth and gain of both microstrip and stripline-fed single antenna are
43 percent and 5 to 10 dBi with low cross polarizations for all frequencies. The array antenna was
measured to have 29 to 60 percent impedance bandwidths depending on the different types of beam
scan angles. The gain of the array antenna is 8 to 13 dBi, and the beams are directed as required
with /- 3 degrees beam scan angle tolerance. The array antenna had a small offset as compared with
simulated results because of the fabrication process such as alignment, distorted feed lines while
etching, and etc, but the bandwidths and array patterns were acceptable.
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The Effects of Automatic Emotion Regulation on the Desirability BiasBench, Shane William 2011 May 1900 (has links)
The goal of the present investigation was to explore the effects of automatic emotion regulation on the desirability bias. The desirability bias is the tendency to believe that one will experience desirable outcomes and not experience undesirable outcomes. Previous research has demonstrated that the desirability bias is due to affective reactions to potential events. Further, deliberate emotion regulation has been shown to reduce the desirability bias. The present investigation explored whether the desirability bias can be reduced by priming a nonconscious goal to regulate emotion before experience of affective reactions to an event. Participants were primed to either express or regulate their emotions before playing a game of chance where cards could result in positive, negative or neutral outcomes. Results showed that the method of priming emotion regulation or expression did not effectively elicit nonconscious goals. Because the manipulation was not effective, the effect of automatic emotion regulation on the desirability bias could not be examined and there was no effect of the prime on bias. Despite the failed manipulation, the findings are still beneficial to the desirability bias literature in that they demonstrate a clear desirability bias in participants' predictions with the use of a within-subjects design. A follow up study using a stronger prime of regulation to test the influence of automatic emotion regulation in reducing the desirability bias is discussed.
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The Cognitive Costs of Regulating Implicit ImpulsesFlores, Sarah A. 2011 May 1900 (has links)
Individuals who are members of stigmatized groups, such as lesbians, gays, and bisexuals, have cognitive deficits in situations that are threatening or hostile to the group in question. Stereotype threat and stigma threat research suggests these cognitive deficits occur in people who identify with stigmatized groups as a result of anxiety. Yet regulating impulses may also create cognitive deficits because it is effortful and diminishes the ability to perform cognitive tasks. This study investigates whether the regulation of undesired sexual impulses causes cognitive deficits in threatening situations even in people who do not identify with a stigmatized group. An implicit measure of sexual attraction to the same gender was administered to participants who self-identified as heterosexual (n = 317). Sexual impulses were primed by asking participants to write about an attractive person of the same or opposite sex or a neutral object. An interaction was found between implicit same sex attraction and the salience of same sex attraction in predicting self-control performance. Participants with a higher level of implicit same sex attraction performed worse on a self-control task after writing about the attractiveness of a same sex person. People with implicit same sex attraction who identify as heterosexual may have more difficulty with tasks requiring self-control or regulatory abilities as well as worse performance outcomes in work and school settings.
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Dual Threshold Voltage SRAM & BIST ComparatorsLee, Po-Ming 24 September 2003 (has links)
Since the invention of SRAM (Static Random Access Memory), many improvements have been proposed. The major targets are speed, area, and power consumption. The evolution of the CMOS process technology makes it possible to implement SRAM by using dual threshold voltage transistors. Hence, we will use TSMC (Taiwan Semiconductor Manufacturing Company) 0.25 $mu$m 1P5M CMOS process to realize the dual threshold voltage SRAM in this thesis. In order to reduce SRAM
internal power consumption, we also propose quenchers to suppress unwanted oscillation between bit lines.
In addition, several types of BIST (Build In Self Test) comparators are also proposed to test the mentioned SRAM. After detailed simulations, the proposed comparators possess impressive results in high fan-in, low transistor count, and high speed.
The proposed SRAM and BIST comparators are fabricated by the CMOS process provided by National Science Council Chip Implementation Center (CIC). The measurements of the chips are fully corrected to meet the design goals.
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Regional Economic Development Policy in Mainland China¡XA Comparative Study of Coastal and Interior ProvincesCheng, ming-cheng 16 June 2005 (has links)
The thesis is want to see ¡]dual economy¡^phenomenon in the process of economic development ¡Cdiscuss about (the disparity between the rich and the poor). in the traditions and the modern both competitiveness¡Cobserved on (dependency Theory) below .in the interior provinces are general self-doubt phenomenon and display light development¡CThe huge unbalanced economic development difference will cause not only economic crsis but also political crisis resulting from people's dissatisfaction on the decline of living standard¡C
In this thesis to make a study of goals¡CFirst of all ,from true affairs statistical data above detailed to study and analysis¡CIt's helpful to me probe into institutional changes of China and to explain differences of economic development and structure between regions¡CFinally, I'm try to from make a study of economic development look into discover and suggest¡Ccan to provide our's government to draft Mainland China strategy in accordance with important to consult. This thesis can to provide Taiwan investment the development strategy and location factors suggest in China's guidebook.
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The space B(pi) and its dualYang, Po-chin 16 June 2005 (has links)
The space B(pi), defined by s.n. function (Phi)(pi)(x_{1},...), were discussed in details in [8], and it is shown that B(pi) is the dual space of B(Pi)^0, which is the closure of the polynomials in B(Pi), the space of analytic function defined by the s.n. function (Phi)(Pi)(x_{1},...), provided that {pi_{n}} satisfies some regularity condition. In this article, we will show that in fact we have the relation (B(Pi)^0)^* approx B(pi), B(pi)^* approx B(Pi). This is an interesting analogy to the classical duality between the operator ideal (S(Pi))^(0), S(pi) and S(Pi), or, the s.n. ideal defined by (Phi)(Pi) and (Phi)(pi).
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Electrical Analysis and Physics Mechanism of Dual-gate Amorphous Silicon Thin Film TransistorChen, Min-chen 09 July 2007 (has links)
The traditional displayer ¡V CRT has already been substituted by liquid crystal displayer (LCD).The a-Si TFT is used to be a switch, while the size of the displayer increases, the require of the performance and quality of TFTs is more and more better. Therefore, it is very important subject to study the stability and to improve the performance of a-Si TFTs.
In this thesis, we fabricate another new structure (asymmetry dual-gate TFTs).For asymmetry dual-gate TFTs, the ITO back gate is extended to the middle of the channel and only covered on the drain contact. The new structure has the advantages of dual-gate TFTs. With dual-channel conduction, it exhibit higher Ion and lower photo leakage current performance than the conventional inverted staggered TFTs.
In addition, we use the asymmetry dual-gate structure to investigate how the parasitic capacitance influences the feed-through voltage by C-V measurement. We also to investigate the influences of electrical characteristics with the ITO back gate whether or not overlap the source contact. The asymmetry in on current with source-drain swapping can be attributed to the difference in the ITO back gate whether overlaps the source contact. Finally, it simulated the process of the degradation on the TFTs to find the stability mechanism of the TFTs.
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