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Using Visible and Near Infrared Diffuse Reflectance Spectroscopy to Characterize and Classify Soil ProfilesWilke, Katrina Margarette 2010 August 1900 (has links)
Visible and near infrared diffuse reflectance spectroscopy (VisNIR-DRS) is a
method being investigated for quantifying soil properties and mapping soil profiles.
Because a VisNIR-DRS system mounted in a soil penetrometer is now commercially
available for scanning soil profiles in situ, methodologies for using scans to map soils
and quantify soil properties are needed. The overall goal of this research is to investigate
methodologies for collecting and analyzing VisNIR-DRS scans of intact soil profiles to
identify soil series. Methodologies tested include scanning at variable versus uniform
moistures, using individual versus averaged spectra, boosting an intact spectral library
with local samples, and comparing quantitative and categorical classifications of soil
series. Thirty-two soil cores from two fields, representing three soil series, were
extracted and scanned every 2.5 cm from the soil surface to 1.5 m or to the depth of
parent material at variable field moist conditions and at uniform moist condition.
Laboratory analyses for clay, sand, and silt were performed on each horizon. Soil series
were classified using partial least squares regression (PLS) and linear discriminant
analysis (LDA). A Central Texas intact spectral library (n=70 intact cores) was used for PLS modeling, alone and boosted with the two fields. Because whole-field independent
validation was used, relative percent difference (RPD) values were used to compare
model performance. Wetting soils to uniform moisture prior to scanning improved
prediction accuracy of total clay and RPD improved by 53 percent. Averaging side-by-side
scans of the same soil profile improved prediction accuracy of RPD by 10 percent. When
creating calibration models, boosting a library with local samples improved prediction
accuracy of clay content by 80 and 34 percent for the two fields. Principal component plots
provided insight on the spectral similarities between these datasets. Overall, using PLS
alone performed the same as LDA at predicting soil series. Most importantly, results of
this project reiterate the importance of fully-independent calibration and validation for
assessing the true potential of VisNIR-DRS. Using VisNIR-DRS is an effective way for
in situ characterization and classification of soil properties.
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Molecular characterization on a t(1;1)(p13;p36) acute megakaryoblastic leukemia (AMKL)Hsieh, Ya-lan 27 October 2004 (has links)
Acute megakaryoblastic leukemia (AMKL) was first described by Von Boros and Karangi in 1931, was a result of developments in ultrastructural cytochemistry and immunologic phenotyping acute myeloid leukemia (AML) of megakaryocytic lineage have been diagnosed increasingly. The French-American-British (FAB) Co-operative Group established the criteria for the diagnosis and added this category as a distinct subtype of AML (M7) in 1985. The main subtypes of AML in the infants are M4, M5, and M7. One 25-day-old infant was referred to the hospital for further examination of white blood cell. Hepatosplenomegaly and anemia were physically examined, and he was diagnosed to be an AMKL case. Abnormal karyotype 46,XY,t(1;1)(p13;p36) was observed in this patient. This study aims to identify the AMKL potentially related genes on the breakpoints of Homo sapiens autosomal (HSA) 1p13 and 1p36 in this case by candidate gene approaches. Data-mining of the AMKL potentially related genes on breakpoints of HSA1p13 and 1p36 through NCBI Map Viewer Database, OMIM Morbid Map, and OMIM Gene Map were performed. We identified three candidate genes on HSA1p13 and 15 candidate genes on HSA 1p36. RBM15-MKL1 fusion on t(1;22)(p13;q13) was reported to be AMKL genes by Ma et al., Mercher et al., and the Mitelman Database of Chromosome Aberrations in Cancer. We anticipated RBM15 is also a related gene on HSA1p13 in this AMKL case, and compared the Gene Ontology terms between MKL1 and these 15 candidate genes on HSA1p36. SKI becomes our first candidate gene on 1p36 in this case. To identify candidate genes locating at HSA1p13 and 1p36, including RBM15 and SKI were screened at both cDNA and genomic DNA levels. According to these results, RBM15 and SKI are more likely to be candidate genes. Thus RBM15 and SKI may be the novel AMKL genes in t(1;1)(p13;p36) AMKL patients.
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Two Characterizations of Commutativity for C*-algebraKo, Chun-Chieh 11 June 2002 (has links)
In this thesis, We investigate the problem of when a C*-algebra is commutative through continuous functional calculus, The principal results are that:
(1) A C*-algebra A is commutative if and only if
e^(ix)e^(iy)=e^(iy)e^(ix),
for all self-adjoint elements x,y in A.
(2) A C*-algebra A is commutative if and only if
e^(x)e^(y)=e^(y)e^(x)
for all positive elements x,y in A.
We will give an extension of (2) as follows: Let
f:[a,b]-->[c,d] be any continuous strictly monotonic function where a,b,c,d in R, a<b,c<d. Then a C*-algebra A is commutative if and only if
f(x)f(y)=f(y)f(x),
for all self-adjoint elements x,y in A with spec(x) in [a,b] and spec(y) in [a,b].
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Numerical simulations and predictive models of undrained penetration in soft soilsShi, Han 01 November 2005 (has links)
There are two aspects in this study: cylinder penetrations and XBP (Expendable
Bottom Penetrometer) interpretations. The cylinder studies firstly investigate the
relationship between the soil resisting force and penetration depth by a series of rateindependent
finite element analyses of pre-embedded penetration depths, and validate
the results by upper and lower bound solutions from classical plasticity theory.
Furthermore, strain rate effects are modeled by finite element simulations within a
framework of rate-dependent plasticity. With all forces acting on the cylinder estimated,
penetration depths are predicted from simple equations of motion for a single particle.
Comparisons to experimental results show reasonable agreement between model
predictions and measurements.
The XBP studies follow the same methodology in investigating the soil shearing
resistance as a function of penetration depth and velocity by finite element analyses.
With the measurements of time decelerations during penetration of the XBP, sediment
shear strength profile is inferred from a single particle kinetic model. The predictions
compare favorably with experimental measurements by vane shear tests.
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Development of a heat-balance model for the characterization of wax blockage in flowlinesOmbu, Ebiaye Valerie 12 April 2006 (has links)
The presence of a blockage in a pipeline will alter the fluid dynamics of a flowing
system in terms of the heat, mass and velocity characteristics. The analysis of the fluid
dynamics is based on balances taken on the overall system to qualitatively and
quantitatively assess the effects of the blockage. Pioneer work in the area of mass and
momentum effects of blockages led to the development of blockage type curves useful in
characterizing blockages from limited information. This work is an extension of
previous work and is based on the application of a simplistic energy balance approach to
characterize blockages in pipelines. The resulting heat models for the case of both a
partially and fully-blocked flowline correctly predict the effect of wax deposition.
Dimensionless temperature-based blockage maps developed here can be used in
modeling unique cases where only two of the three necessary conditions are given. The
heat model matches results from commercial software within a limited range of
restricted flow conditions.
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3D characterization of acidized fracture surfacesMalagon Nieto, Camilo 17 September 2007 (has links)
The complex interrelations among the different physical processes involved in acid
fracturing make it difficult to design, and later, to predict the outcome of stimulation
jobs. Actual tendencies require the use of computational models to deal with the
dynamic interaction of variables. This thesis presents a new study of acidized surface
textures by means of a laser profilometer to improve our understanding of the remaining
etched surface topography and its hydraulic response.
Visualization plots generated by the profilometer identified hydrodynamic channels that
could not be identified by the naked eye in acidized surfaces. The plots clarified the
existence of rock heterogeneities and revealed how the processes of dissolution function
in chalk rock.
Experimental data showed clearly that the effect of dissolution depends on the type of
rock and the fluid system; dolomite, for example, dissolves more rapidly but more
roughly than limestone. Fluid leakoff rate and temperature also affect the dissolution.
Further research is necessary to clarify the effects of conductivity.
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The Applications of Pulse Shaping in Ultra-broad Bandwidth Pulse Characterization and Multi-pulse GenerationLiu, Shin-Cheng 04 November 2008 (has links)
This thesis utilize pulse shaping in characterization of ultra-broad bandwidth laser pulse and multi-pulse generation.
Using angle-dithering technique, time-integrating phase-matching bandwidth can be increased significantly even with a thin crystal. We also characterize the pulse by angle-dithered MIIPS( intrapulse interference phase scan ) technique. An addition advantage of using a thick crystal is increased signal strength.
In addition, we provide a method to generate multi-pulses and proceed Michelson interferometeric autocorrelator by controlling the spectral amplitude and phase of the pulse. To compare with the past method, the efficiency was obtained from 33% to 80% , and the stability and time resolution of delay time can be improved. We expect this method applied to narrow-band frequency-tunable THz wave genetration will be better.
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Reservoir characterization using a capacitance resistance model in conjunction with geomechanical surface subsidence modelsWang, Wenli, master of science in petroleum engineering 20 February 2012 (has links)
Extraction of oil and gas can cause reduction in pore pressure, occasionally resulting in subsequent compaction that forms a surface subsidence bowl, especially in shallow reservoirs. In the last 10 years, there has been over 10 feet of subsidence in parts of the Lost Hills oil field in California (Bruno et al.,1992). The surface subsidence at Lost Hills not only causes damage to surface facilities and wells, but also reactivates faults and reduces rock permeability. Subsidence makes reservoir optimization difficult. Hence, it is important to assess or predict the surface subsidence and the reasons for subsidence early in the life of an oil field to make an optimization plan.
We use jointly the capacitance resistance model (CRM) (Alberoni et al., 2002 and Yousef, et al., 2006) that relies only on injection and production data, and the InSAR satellite imagery of surface subsidence. From CRM simulations, we estimate the connectivity between injectors and producers as well as general water flow directions from individual injectors. We then superimpose well connectivity and InSAR imagery to diagnose the reasons for the subsidence. Using new surface subsidence models, which are based on the continuity equation of CRM and rock mechanics, we are able to predict the average surface subsidence at Lost Hills from the injection and production rates.
Our work shows that there was significant volumetric rock damage at Lost Hills and the well connectivity changed dramatically with time because of reservoir compaction and the rock damage. We conclude that for a soft, fragile and nearly- impermeable rock such as the diatomite, high injection rate weakens the rock and creates dynamic water flow tubes or ‘channels’ without providing good pressure support to the reservoir. These high permeability ‘channels’ re-circulate most of the injected water between the injectors and producers.
Our CRM/InSAR approach is new and gives insights into the time-dependent and spatially variable fluid flow fields in a relatively shallow waterflood. Consequently, we may be able to suggest optimum water injection strategies to enhance oil production, while minimizing rock damage and surface subsidence. In addition, the proposed surface subsidence models are convenient and reliable to predict the average surface subsidence. / text
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Designs and methodologies for post-silicon timing characterizationJang, Eun Jung 24 October 2013 (has links)
Timing analysis is a key sign-off step in the design of today's chips, but technology scaling introduces many sources of variability and uncertainty that are difficult to model and predict. The result of these uncertainties is a degradation in our ability to predict the performance of fabricated chips, i.e., a lack of model-to-hardware matching. The prediction of circuit performance is the result of a complex hierarchy of models ranging from the basic MOSFET device model to full-chip models of important performance metrics including power, frequency of operation, etc. The assessment of the quality of such models is an important activity, but it is becoming harder and more complex with rising levels of variability and the increase in the number of systematic effects observed in modern CMOS processes. The purpose of this research is (i) to introduce special-purpose test structures that specifically focus on ensuring the accuracy of gate timing models, and (ii) to introduce methods that analyze the extracted information, in the form of path delay measurements, using the proposed test structures. The certification of digital design correctness (the so-called signoff) is based largely on the results of performing Static Timing Analysis (STA), which, in turn, is based entirely on the gate timing models. The proposed test structures compare favorably to alternative approaches; they are far easier to measure than direct delay measurement, and they are much more general than simple ring-oscillator structures. Furthermore, the structures are specified at a high level, allowing them to be synthesized using a standard ASIC place-and-route flow, thus capturing the local layout systematic effects which can sometimes be lost by simpler (e.g., ring oscillator) structures. For the silicon timing analysis, we propose methods that deduce segment delays from the path delay measurements. These estimated segment delays using our methods can be directly compared with the timing models. Therefore, it will be easy to identify the cause of timing mismatches. Deducing segment delays from path delays, however, is not an easy problem. The difficulties associated with deconvolving segment delays from measured path delays come from insufficient sampling points. To overcome this limitation, we first group the segments based on certain characteristics of segments, and adapt Moore-Penrose pseudo-inverse method to approximately solve the segment delays. Secondly, we used equality-constrained least squares methods, which enable us to find a unique and optimized solution of segment delays from underdetermined systems. We also propose another improved test structure that has a built-in test pattern generator, and hence does not require ATPG (Automatic Test Pattern Generation). It is a self-timed circuit, and this feature makes the test structure run as fast as it can. Therefore, measurements can be made under high speed switching conditions. Finally, we can study dynamic effects such as timing effects of different levels of switching activities and voltage drop with the new test structure. / text
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Novel stochastic inversion methods and workflow for reservoir characterization and monitoringXue, Yang, active 2013 18 February 2014 (has links)
Reservoir models are generally constructed from seismic, well logs and other related datasets using inversion methods and geostatistics. It has already been recognized by the geoscientists that such a process is prone to non-uniqueness. Practical methods for estimation of uncertainty still remain elusive. In my dissertation, I propose two new methods to estimate uncertainty in reservoir models from seismic, well logs and well production data. The first part of my research is aimed at estimating reservoir impedance models and their uncertainties from seismic data and well logs. This constitutes an inverse problem, and we recognize that multiple models can fit the measurements. A deterministic inversion based on minimization of the error between the observation and forward modeling only provides one of the best-fit models, which is usually band-limited. A complete solution should include both models and their uncertainties, which requires drawing samples from the posterior distribution. A global optimization method called very fast simulated annealing (VFSA) is commonly used to approximate posterior distribution with fast convergence. Here I address some of the limitations of VFSA by developing a new stochastic inference method, named Greedy Annealed Importance Sampling (GAIS). GAIS combines VFSA with greedy importance sampling (GIS), which uses a greedy search in the important regions located by VFSA to attain fast convergence and provide unbiased estimation. I demonstrate the performance of GAIS on post- and pre-stack data from real fields to estimate impedance models. The results indicate that GAIS can estimate both the expectation value and the uncertainties more accurately than using VFSA alone. Furthermore, principal component analysis (PCA) as an efficient parameterization method is employed together with GAIS to improve lateral continuity by simultaneous inversion of all traces. The second part of my research involves estimation of reservoir permeability models and their uncertainties using quantitative joint inversion of dynamic measurements, including synthetic production data and time-lapse seismic related data. Impacts from different objective functions or different data sets on the model uncertainty and model predictability are investigated as well. The results demonstrate that joint inversion of production data and time-lapse seismic related data (water saturation maps here) reduces model uncertainty, improves model predictability and shows superior performance than inversion using one type of data alone. / text
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