Hydraulic fracturing of transverse isotropic reservoirs is of major interest for reservoir stimulation and in-situ stress estimation. Rock fabric anisotropy not only causes in-situ stress anisotropy, but also affects fracture initiation from the wellbore. In this study a semi-analytical method is used to investigate these effects with particular reference to shale stimulation. Using simplifying assumptions, equations are derived for stress distribution around the wellbore's walls. The model is then used to study the fracture initiation pressure variations with anisotropy. A sensitivity analysis is carried out on the impact of Young's modulus and Poisson's ration, on the fracture initiation pressure. The results are useful in designing hydraulic fractures and also can be used to develop information about in-situ rock properties using failure pressure values observed in the field. Finally, mechanical and permeability anisotropy are measured using Pulse Permeameter and triaxial tests on Pierre shale.

The Shield&rsquo / s Diagram has been the key stone for the description of initiatial motion of a particle in open channel flow. Data in Shield&rsquo / s study and further studies are collected in channels. However, the approximation of these data for the case of withdrawal of sediment or clean water through bottom outlets has not been confirmed. Furthermore, two phase models run to simulate the phenomenon so far have used brine and water combination. In this study, an experimental attempt is made to study the behavior of deposits subject to withdrawal from a bottom outlet where there are not enough parameters to calculate the bottom shear stress and consequently the dimensionless parameters generally used for the description of initiation of motion. The experimental set up used for this purpose is a 1 m long and 0.35 m wide channel such that at the downstream of the channel there is a horizontal slit representing the bottom outlet. During the experiments, fresh water and sand with D50 = 0.298 mm and D50 = 0.912 mm are used. Two different widths of the slit, namely 0.35 m and 0.0875 m are investigated. Based on the observations of the incipient motion of the sediment, the findings in the form of a relationship among the discharge through the bottom outlet, and some other relevant parameters are reported. In addition, a comparison of these data with the literature by the help of some newly defined dimensionless parameters for the description of the initiation of motion is included.

Project (D. Min.)--Perkins School of Theology, Southern Methodist University, 1982. / Abstract. Includes bibliographical references (leaves 141-146).

Reproduction de : Thèse doctorat : Sciences de l'Information et de la Communication : Paris 8 : 2005. / Titre provenant de l'écran titre. Bibliogr. : f. 269-284.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 60-72).

Thesis (D. Min.)--Catholic Theological Union at Chicago, 1999. / Includes abstract and vita. Includes bibliographical references (leaves 187-190).

Thesis (M.A.P.S.)--Catholic Theological Union at Chicago, 2002. / Vita. Includes bibliographical references (leaves [54]-55).

Cotton fiber development is a fundamental biological phenomenon. In spite of its economical importance, a large proportion of cotton fiber initiation is unknown. A naked seed mutant (N1N1) was compared with its isogenic lines of cotton (Gossypium hirsutum, TM-1) using a 70-mer oligonucleotide microarray that contained 1,536 features designed from a subset of cotton fiber ESTs. Statistical analysis and quantitative RT-PCR identified 23 "fiber-associated" genes. The annotation suggested that the temporal regulation of genes involved in transcriptional and translational regulation, signal transduction, and cell differentiation during early stages of fiber development. To get a large view of fiber initiation, a new cotton oligonucleotide microarray was developed containing sequences from an ovule EST library from Gossypium hirsutum L. T̲M̲-1 immature o̲vules (GH_TMO), a set from Jonathan Wendel's lab at Iowa State University, and the pilot set of oligos used for previous study. Global gene expression studies were performed with microdissected fiber initials (or epidermis) and inner ovules to investigate fiber preferentially expressed genes. Laser capture microdissection and antisense RNA (aRNA) amplification allowed us to collect fiber initials (0 DPA and 2 DPA) or epidermal layers (-2 DPA) from whole ovule tissues. The gene expression profiles of fiber initials showed up-regulation of fiber proteins, myb transcription factors, and hormonal regulators as well as trichome related factors during fiber initiation. In each developmental stage, different sets of gene categories in molecular function or biological processes were over- or under-represented, suggesting temporal regulation of genes during fiber development. One of the possible "fiber associated genes" found in microarray analyses, RD22 like gene (GhRDL), was highly enriched in the epidermis of cotton ovules during fiber initiation. The function of GhRDL was studied with the Arabidopsis trichome system which shares many similarities with fiber development. Overexpression of 35S::GhRDL into Arabidopsis thaliana Columia-0 induced seed hairs (or seed trichomes) and pRDL:GUS was localized in Arabidopsis seeds. This suggests that GhRDL plays an important role in the seed trichome development and can be a key player in cell differentiation and fiber development. / text

Vesicular stomatitis virus (VSV) infection causes inhibition of host protein synthesis, in part by sequestering initiation factors required for mRNA cap recognition. The viral mRNAs share a common mRNA structure to those of the host cell, with a 5' cap and 3' polyadenylate tail, but continue to be efficiently translated despite host translational shutoff. This observation suggests that a non-canonical translation pathway is utilized for viral protein synthesis. To investigate this pathway, we performed an RNA interference screen to identify genes required for VSV replication. In contrast to bulk cellular translation, viral translation is hypersensitive to knockdown of a protein constituent of the 60S ribosomal subunit, rpL40. Depletion of rpL40 diminishes VSV protein synthesis by >90% and is restored through complementation with an siRNA-resistant mutant of rpL40. To delineate the mechanism by which rpL40 is required for viral protein synthesis, we reconstituted translation of VSV mRNA in yeast extracts in vitro. In the absence of rpL40, we show that the two ribosomal subunits fail to associate on VSV mRNA, and the small subunit does not scan to the initiation codon. Regulation by rpL40 occurs in context of the large subunit, providing direct evidence for translational control by the ribosome itself. This rpL40- dependent mechanism of translation initiation is broadly conserved within eukaryotes, governed solely through an RNA determinant, and is utilized by several viruses within the order Mononegavirales. To determine whether a subset of cellular transcripts also require rpL40 for translation, we identified polysome-associated mRNAs in yeast by deep sequencing. We demonstrate that in vitro and in vivo translation of candidate mRNAs, including factors involved in stress responses, are inhibited in the absence of rpL40. This finding suggests that rpL40 plays a critical role in transcript-specific translation during cellular stress. Collectively, our work identifies an alternative translation pathway that is specifically dependent on rpL40, revealing a previously unappreciated mechanism of protein synthesis regulation by the ribosome.

The low cycle thermo-mechanical fatigue of laser beam welded conventionally cast Inconel 738, directionally solidified René 80 and single crystal René N5 has been evaluated. Results have been compared to gas tungsten arc and baseline alloy conditions. Metallographic examination of laser beam welds and the associated heat affected zone were conducted by scanning electron microscopy and energy dispersive spectroscopy. The impact of laser beam welding on thermo-mechanical fatigue properties of Inconel 738, René 80 and René N5 has been evaluated and recommendations for improvements and areas of further research have been presented.