The Richtmyer-Meshkov instability (RMI) in the convergent geometry is numerically studied in the framework of ideal magnetohydrodynamics (MHD) and two-fluid plasma in this thesis. The converging RMI usually occurs along with the Rayleigh-Taylor instability (RTI) due to the non-uniform motion or continuous acceleration of the interface. First, we investigate the interaction between a converging cylindrical shock and double density interfaces in the presence of a saddle magnetic field with ideal MHD model. We show that the RMI is suppressed by the magnetic field . However, the extent of the suppression varies on the interface which leads to non-axisymmetric growth of the perturbations. The degree of asymmetry increases when the seed field strength increases. The perturbation amplitude is affected by the competition mechanism between RMI and RTI. It increases when RMI dominates RTI while decreases when RTI dominates. Then, we research the two-fluid plasma RMI of a cylindrical density interface without an initial magnetic field. Varying the Debye length scale, we examine the effects of the coupling between the electron and ion fluids. The charge separation is responsible for the self-generated electromagnetic fields. We show that the Biermann battery effect dominates the generation of magnetic field when the coupling effect is weak. In addition to the RT stabilization effect during flow deceleration, the interfaces are accelerated by the induced Lorentz force. As a consequence, the perturbations develop into the RTI, leading to an enhancement of the perturbation amplitude compared with the hydrodynamic case. Finally, we investigate the linear evolution of two-fluid plasma RMI. We show that the increase of perturbation amplitude is almost contributed by the ion shock-interface interaction. We also examine the effect of magnetic field in the streamwise direction. For a short duration after the ion shock-interface interaction, the growth rate is similar for different initial magnetic field strengths. As time progresses the suppression of the instability due to the magnetic field is observed. The growth rate shows oscillations with a frequency that is related to the ion or electron cyclotron frequency. The instability is suppressed due to the vorticity being transported away from the interface.

Rotating-disk flow has been investigated not only as a simple model of cross flow instability to compare with swept-wing flow but also for industrial flow applications with rotating configurations. However the exact nature of laminar-turbulent transi- tion on the rotating-disk flow is still major problem and further research is required for it to be fully understood, in particular, the laminar-turbulent transition process with absolute instability. In addition the studies of the rotating-disk turbulent boundary- layer flow are inadequate to understand the physics of three-dimensional turbulent boundary-layer flow. In present thesis, a rotating-rotating disk boundary-layer flow has been inves- tigated experimentally using hot-wire anemometry. A glass disk with a flat surface has been prepared to archieve low disturbance rotating-disk environment. Azimuthal velocity measurements using a hot-wire probe have been taken for various conditions. To get a better insight into the laminar-turbulent transition region, a new way to describe the process is proposed using the probability density function (PDF) map of azimuthal fluctuation velocity. The effect of the edge of the disk on the laminar-turbulent transition process has been investigated. The disturbance growth of azimuthal fluctuation velocity as a function of Reynolds number has a similar trend irrespective of the various edge conditions. The behaviour of secondary instability and turbulent breakdown has been in- vestigated. It has been found that the kinked azimuthal velocity associated with secondary instability just before turbulent breakdown became less apparent at a cer- tain wall normal heights. Furthermore the turbulent breakdown of the stationary mode seems not to be triggered by its amplitude, however, depend on the appearance of the travelling secondary instability. Finally, the turbulent boundary layer on a rotating disk has been investigated. An azimuthal friction velocity has been directly measured from the azimuthal velocity profile in the viscous sub-layer. The turbulent statistics normalized by the inner and outer sclaes are presented. / QC 20120529

Indiana University-Purdue University Indianapolis (IUPUI) / The Fanconi anemia (FA) pathway consists of 21 genes that maintain genomic stability and prevent cancer. Biallelic mutations within this network cause Fanconi anemia, an inherited bone marrow failure and cancer predisposition syndrome. Heterozygous inborn mutations in FA genes increase risk of breast/ovarian cancers, and somatic mutations occur in malignancies in non-Fanconi patients. Understanding the tumor suppressive functions of FA signaling is important for the study of Fanconi anemia, inherited cancers, and sporadic cancers. The FA network functions as a genome guardian throughout the cell cycle. In addition to the well-established roles of FA proteins in interphase DNA replication/repair, the FA pathway controls mitosis by regulating the spindle assembly checkpoint (SAC) to ensure proper chromosome segregation. The SAC consists of several tumor suppressors, including Mad2, and SAC impairment predisposes to aneuploidy and cancer. However, the in vivo contribution of SAC dysfunction to malignant transformation of FA-deficient cells remains unknown. Furthermore, the mechanisms by which FA proteins regulate the SAC are unclear. To test whether SAC dysfunction drives genomic instability and tumorigenesis in FA, we generated a novel FA-SAC model by intercrossing Fancc-/- and Mad2+/- mice. The intercrossed mice displayed heightened aneuploidy secondary to exacerbated SAC dysfunction. Importantly, these mice were prone to developing hematologic malignancies, particularly leukemia, faithfully recapitulating the clinical phenotype of Fanconi anemia. Upon establishing SAC dysfunction as a driver of tumorigenesis in FA, we next explored the mechanism by which FANCC regulates the SAC. We demonstrated that the mitotic kinase CDK1 phosphorylates FANCC to regulate subcellular localization and SAC function of FANCC during mitosis. Our study highlights the essential role of compromised chromosome segregation in the development of leukemia due to impaired FA signaling. This work furthers our knowledge of FANCC signaling at the SAC, and has implications for future use of mitotic-centered therapies for FA-associated tumors. / 2 years

Some have suggested acute increases in musculotendinous stiffness (k) following whole body vibration (WBV). Others propose that chronic ankle instability (CAI) may alter k of the lower extremity. Changes in proprioceptive activity and/or gamma motoneuron activation post-WBV and/or due to CAI could lead to alterations in k. However, little is known about acute effects of WBV on k and less is known about changes in k with CAI. PURPOSE: Assess differences in vertical and joint k between healthy and CAI subjects during single-limb landings and detect alterations in k measures post-vibration. METHODS: Subjects were identified as CAI via the FAAM, MAII and special testing. Thirty-five CAI subjects (17 males, 18 females; age = 22 ± 7 yr; height = 1.73 ± 0.23 m; mass = 70 ± 30 kg) and 35 matched healthy subjects (17 males, 18 females; age = 23 ± 5 yr; height = 1.73 ± 0.21 m; mass = 70 ± 35 kg) qualified for this study. Kinetic (2000 Hz) and kinematic (250 Hz) data were recorded during several jump landings pre- and post-WBV. Five repetitions of WBV, at 26 Hz and 4 mm amplitude, were introduced between pre- and post-WBV jump trials. The jump task included a double-limb jump followed by a single-limb landing and a subsequent contralateral hop. Vertical k (∆vertical GRF/center of mass vertical displacement), hip, knee and ankle joint k (∆joint moment/∆joint angle) were calculated, averaged across five successful pre-WBV and across six post-WBV trials. An ANOVA was used to detect between-group differences, while an ANCOVA was used to analyze within-group differences post-WBV using pre-measures as covariates. A pseudo-Bonferroni adjustment was performed prior to statistical analysis (p < 0.01). RESULTS: No between-group differences were observed for any of the variables (F1,68 = 0.020 to 1.400, p = 0.240 to 0.890). A significant increase in vertical k was observed post-WBV for the healthy group (t67 = 2.760, p = 0.008), but not for the CAI group (t67 = 0.370, p = 0.720). The CAI group did demonstrate a decrease in ankle (t67 = -3.130, p = 0.003) and knee (t67 = -3.490, p = 0.001) joint k post-vibration. No other within-group differences were observed post-WBV (p > 0.01). CONCLUSIONS: It appears that WBV does acutely increase vertical k in healthy subjects. However, this treatment effect was not observed in CAI. Further research is needed to assess how k is regulated in CAI subjects and why CAI subjects responded differently to WBV.

The family may be defined as a group of interacting personalities of neer tie or blood-kin; namely, husband, wife, children, and may include grand parents.The origin of the family is not clear, since we find marriage in a rather highly developed form among the most primitive tribes. The family has taken on different forms in various places and under varying circumstances. Perhaps monogamy, the union of one man and one woman, is the most prevalent fore of marriage, not only in the United States but among all peoples and in all ages. Polygyny, the union of one man with several women, is not uncommon. Although it is not permitted in the United States, it is practiced in certain societies but confined largely to the wealthy. Polyandry, the union of one woman with several men, is not so common a form of marriage; however, it may be found in Tibet and among some of the mountain tribes of India.

To aid in forest management, various approaches using Geographic Information Systems (GIS) have been used to identify the spatial distributions of relative slope instability. This study presents a systematic evaluation of three common slope instability modeling approaches applied in the Blue Ridge Mountains of Virginia. The modeling approaches include the Qualitative Map Combination, Bivariate Statistical Analysis, and the Shallow Landsliding Stability (SHALSTAB) model. Historically, the qualitative nature of the first model has led to the use of more quantitative statistical models and more deterministic physically-based models such as SHALSTAB. Although numerous studies have been performed utilizing each approach in various regions of the world, only a few comparisons of these approaches have been done in order to assess whether the quantitative and deterministic models result in better identification of instability. The goal of this study is to provide an assessment of relative model behavior and error potential in order to ascertain which model may be the most effective at identifying slope instability in a forest management context. The models are developed using both 10-meter and 30-meter elevation data and outputs are standardized and classified into instability classes (e.g. low instability to high instability). The outputs are compared with cross-tabulation tables based on the area (m²) assigned to each instability class and validated using known locations of debris flows. In addition, an assessment of the effects of varying source data (i.e. 10-meter vs. 30-meter) is performed. Among all models and using either resolution data, the Qualitative Map Combination correctly identifies the most debris flows. In addition, the Qualitative Map Combination is the best model in terms of correctly identifying debris flows while minimizing the classification of high instability in areas not affected by debris flows. The statistical model only performs well when using 10-meter data while SHALSTAB only performs well using 30-meter data. Overall, 30-meter elevation data predicts the location of debris flows better than 10-meter data due to the inclusion of more area into higher instability classes. Of the models, the statistical approach is the least sensitive to variations in source elevation data. / Master of Science

This thesis deals with the instabilities of the incompressible boundary-layer flow that is induced by a disk rotating in otherwise still fluid. The results presented are mostly limited to linear instabilities derived from direct numerical simulations (DNS) but with the objective that further work will focus on the nonlinear regime, providing greater insights into the transition route to turbulence. The numerical code Nek5000 has been chosen for the DNS using a spectral-element method in an effort to reduce spurious effects from low-order discretizations. Large-scale parallel simulations have been used to obtain the present results. The known similarity solution of the Navier–Stokes equation for the rotating-disk flow, also called the von Karman flow, is investigated and can be reproduced with good accuracy by the DNS. With the addition of small roughnesses on the disk surface, convective instabilities appear and data from the DNS are analysed and compared with experimental and theoretical data. A theoretical analysis is also presented using a local linear-stability approach, where two stability solvers have been developedbased on earlier work. A good correspondence between DNS and theory is found and the DNS results are found to explain well the behaviour of the experimental boundary layer within the range of Reynolds numbers for small amplitude (linear) disturbances. The comparison between the DNS and experimental results, presented for the first time here, shows that the DNS allows (for large azimuthal domains) a range of unstable azimuthal wavenumbers β to exist simultaneously with the dominantβ varying, which is not accounted for in local theory, where β is usually fixed for each Reynolds number at which the stability analysis is applied. Furthermore, the linear impulse response of the rotating-disk boundary layer is investigated using DNS. The local response is known to be absolutely unstable. The global response is found to be stable if the edge of the disk is assumed to be at infinity, and unstable if the domain is finite and the edge of the domain is placed such that there is a large enough pocket region for the absolute instability to develop. The global frequency of the flow is found to be determined by the edge Reynolds number. / <p>QC 20140708</p>

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