Dynamic Liquid Slosh in Moving Containers

Liquid sloshing is known to strongly influence the directional dynamics and safety performance of highway tank vehicles in a highly adverse manner. Hydrodynamic forces and moments arising from liquid cargo oscillations in the tank under steering and/or braking maneuvers reduce the stability limit and controllability of the partially filled tank vehicles. While the transient fluid slosh within moving containers has been widely investigated, interactions between the sloshing cargo and the vehicle system dynamics have been addressed in only a few studies due to associated challenges. Furthermore, roll stability of heavy tank vehicles have been extensively studied in the absence of transient slosh-induced forces and moments. This dissertation research aims at exploring the fluid slosh in moving containers through analytical methods and developing efficient models for simulating interactions of fluid slosh and vehicle dynamics. A comprehensive review of relevant studies reporting tank trucks accident data, tank design standards, and analysis methods of liquid sloshing in moving containers is initially performed and briefly summarized. The literature review provides not only the essential knowledge for developing an efficient method of analysis, but also demonstrates the needs for addressing limitations in the current standards so as to include effects of liquid sloshing dynamics in road tankers. An analytical model of two-dimensional fluid slosh in horizontal cylindrical tanks subject to a lateral excitation is initially formulated assuming potential flows and linearized free-surface boundary. For this purpose, the fluid domain in the Cartesian coordinates is transformed to the bipolar coordinates, where the Laplace equation could be solved using separation of variables. The resulting hydrodynamic pressure, free-surface elevation, and slosh force and roll moment are compared with the reported experimental and numerical results to illustrate the range of applicability and limitations of the linear slosh theory. The results suggest that the linear theory can yield reasonably accurate predictions of non-resonant lateral slosh in liquid transporting vehicles with significantly less computational effort than the CFD models. A multimodal model of fluid slosh is subsequently developed to study the effect of tank cross-section on transient lateral slosh. Natural frequencies and modes of liquid slosh in tanks of different cross-sections are obtained using a variational Ritz method, which are implemented into the multimodal model. The effect of transient liquid slosh and tank cross-section on rollover stability limits of a tank vehicle is also investigated by integrating the fluid slosh model into a roll plane model of the suspended tank vehicle. The results are presented for four different tank cross-sections: circular; elliptical; modified-oval; and Reuleaux-triangle. The results show that a tank cross-section with lower overall center of mass and lower critical slosh length could yield enhanced roll stability limit under medium- and high-fill conditions. The multimodal method is also employed to investigate the effect of partial longitudinal baffles on the transient lateral slosh. Natural slosh frequencies and modes are computed using a boundary integral solution of the Laplace equation. The computational efficiency is significantly improved by reducing the generalized eigenvalue problem to a standard one involving only the velocity potentials of the elements on the half free-surface length. Damping due to the baffles is estimated from the energy dissipation rate. The results are presented for different designs/lengths of longitudinal baffles, namely, top-mounted; bottom-mounted; and center-mounted baffles. It is shown that the multimodal method yields computationally efficient solutions of liquid slosh within moving baffled containers. The results suggest that a baffle is most effective and efficient when it pierces the free-surface and partly submerged in the liquid. A three-dimensional linear slosh model is further developed to study fluid motions under simultaneously applied lateral and longitudinal excitations, characterizing braking-in-a-turn maneuver, using the multimodal method. Three-dimensional Laplace equation is initially reduced to a two-dimensional Helmholtz equation using separation of variables. A higher order boundary integral solution of the Helmholtz equation is then formulated to compute natural slosh frequencies and modes in a horizontal cylindrical tank of arbitrary cross-section. The results obtained for a circular tank suggested rapid convergence of the natural slosh frequencies and hydrodynamic coefficients. The slosh forces and moments are also computed from the nonlinear analysis of liquid slosh in a tank under various lateral/longitudinal accelerations and fill ratios using the FLUENT software. Comparisons of the results obtained from the linear and nonlinear analyses revealed that the linear slosh theory yields reasonably accurate predictions of the peak slosh forces and moments under lateral/longitudinal accelerations of steady magnitudes of up to 0.3g/0.2g for a tank of aspect ratio of 2.4

Prediction of Boundary Layer Transition Based on Modeling of Laminar Fluctuations Using RANS Approach

AbstractThis article presents a linear eddy-viscosity turbulence model for predicting bypass and natural transition in boundary layers by using Reynolds-averaged Navier-Stokes (RANS) equations. The model includes three transport equations, separately, to compute laminar kinetic energy, turbulent kinetic energy, and dissipation rate in a flow field. It needs neither correlations of intermittency factors nor knowledge of the transition onset. Two transition tests are carried out: flat plate boundary layer under zero and non-zero pressure gradients with different freestream turbulence intensities, and transitional flow over a wind turbine blade at a chord Reynolds number of 3×106. Results are presented in terms of skin friction coefficients. Comparison with the experimental data from both tests evidences a good agreement there is between them

Conformal bounds for the first eigenvalue of the (p,q)(p,q)-Laplacian system

Consider $\left(M,g\right)$ as an $m$-dimensional compact connected Riemannian manifold without boundary. In this paper, we investigate the first eigenvalue $\lambda_{1,p,q}$ of the $\left(p,q\right)$-Laplacian system on $M$. Also, in the case of $p,q >n$ we will show that for arbitrary large $\lambda_{1,p,q}$ there exists a Riemannian metric of volume one conformal to the standard metric of $\mathbb{S}^{m}$

Theoretical and Experimental Investigation of Switch-Like Responses Arising from Multisite Protein Phosphorylation.

Switch-like responses are important regulatory features of biological processes involving binary decisions such as cell division. Multisite protein phosphorylation is a proposed mechanism for achieving switch-like behaviors. For example, it is conjectured that the G1/S transition of the yeast cell cycle occurs in a switch-like fashion due to multisite phosphorylation-triggered degradation of the Sic1 protein. The objective of this dissertation is first to acquire a quantitative and predictive understanding of switch-like behaviors arising from multisite phosphorylation in natural systems, and second to employ this knowledge for the design of synthetic protein devices. We first developed a mathematical model to investigate systematically the role of multisite phosphorylation in the phosphorylation-triggered degradation process of a protein like Sic1. We found that as the number of sites increases, a more switch-like temporal profile can be generated. The steepness is determined synergistically by various factors, including the total number of sites and kinetic parameters. To test our theoretical predictions, we examined the steady-state response of wild-type and mutant Sic1 with various numbers of phosphorylation sites. It was observed that the response of Sic1, measured by its binding to a downstream protein Cdc4 in the degradation pathway, to the Cln2-Cdc28 kinase in vitro is switch-like. Furthermore, the ultrasensitivity decreases as the number of sites decreases. We next showed, through computational analysis, that a multisite protein can exhibit sustainable and tunable oscillations when embedded in a negative feedback loop, formed via inhibition of the rst phosphorylation step. We also designed a protein degradation device based on multiple protein binding domains and carried out preliminary study of its implementation. Our work demonstrates the potential of utilizing multisite proteins or the broader design principle of intramolecular multiple interaction modules, which provides an effective and flexible means for generating high nonlinearity, in creating a wide range of synthetic biological devices. This dissertation suggests quantitative design principles for switch-like stimulusresponse relationships arising from multisite protein phosphorylation, which might be a widespread mechanism in cellular regulation. In addition, our results provide intriguing hypotheses to be investigated experimentally in future work, such as the critical effect of multi-step phosphorylation kinetics.Ph.D.Chemical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/89620/1/varedi_1.pd

Ovarian papillary serous cancer recurrence with ipsilateral isolated axillary lymph node metastasis as an unusual presentation: A case report

Introduction: From among gynecologic cancers, epithelial ovarian cancer (EOC) is the leading cause of mortalities due to gynecologic cancers in the United States, constituting 3.6 of all types of gynecologic cancers. A major reason for this poor treatment outcome is that most EOC patients are frequently diagnosed in advanced stages of the disease. A standard management for EOC patients involves a primary cytoreductive surgery followed by adjuvant chemotherapy if needed. However, primary breast cancer is one of the most common malignancies in women, and metastasis of other cancers to the breast is relatively rare. Case Presentation: Here, we report the case of a 70-year-old patient who five years ago had undergone laparotomy due to post-menopausal bleeding, adnexal mass, and elevated CA125. With the diagnosis of metastatic papillary serous, she underwent primary cytoreductive surgery and adjuvant chemotherapy. Regarding the history of ovarian cancer diagnosed five years ago, and further examination of this suspicious lymph node, and rejection of the risk of breast cancer, the patient was examined for the risk of metastasis. In biopsy and immunohistochemistry study, metastatic lymph node was diagnosed with the origin of epithelial ovarian cancer, and the patient was treated with beta-taxol + carboplatin, and the size of the axillary lymph node shrank. Conclusion: Regarding the unusual nature of recurrence of ovarian cancer as isolated axillary lymph node involvement, this report emphasizes the importance of considering metastasis in the axilla and its differential diagnosis from breast cancer in patients with a history of ovarian cancer, since prognoses and treatments are different for each diagnosis. © 2018, Mashhad University of Medical Sciences. All Rights Reserved

Clinical Outcomes With Dabrafenib Plus Trametinib in a Clinical Trial Versus Real-World Standard of Care in Patients With BRAF-Mutated Advanced NSCLC

INTRODUCTION: BRAF mutations are rare in patients with NSCLC, and treatment options are limited. Dabrafenib plus trametinib (dab-tram) was approved for BRAF(V600)-mutated advanced NSCLC (aNSCLC), based on results from a phase 2 study (NCT01336634). This retrospective analysis compared the effectiveness of dab-tram, based on previously reported clinical trial data, versus real-world standard of care in patients with BRAF-mutated aNSCLC. METHODS: Real-world cohorts were derived from a deidentified real-world database (2011–2020) and included patients with BRAF-mutated aNSCLC receiving first-line platinum-based chemotherapy (PBC), first-line immune checkpoint inhibitors (ICIs) plus PBC, or second-line ICIs. Weighting by odds was used to estimate the average treatment effect of the treated. RESULTS: For first-line dab-tram versus PBC, the hazard ratio (HR; 95% confidence interval) for death in unweighted and weighted analyses was 0.65 (0.39–1.1) and 0.51 (0.29–0.92; p = 0.03), respectively; unweighted and weighted median overall survival was 17.3 (12.3–40.2) versus 14.5 (9.2–19.6) months and 17.3 (14.6-not reached) versus 9.7 (6.4–19.6) months, respectively. Hazard ratio of death in unweighted and weighted analyses was 0.56 (0.29–1.1) and 0.57 (0.28–1.17), respectively, with first-line dab-tram versus PBC plus ICI, and 0.65 (0.39–1.07) and not reported (Cox proportional-hazards assumption violated), respectively, with second-line dab-tram versus ICI. CONCLUSIONS: In this indirect comparison in patients with BRAF-mutated aNSCLC, the risk of death was lower and median overall survival was longer with first-line dab-tram versus PBC. In analyses of dab-tram versus first-line PBC plus ICI or second-line ICI, sample sizes were small and findings were inconclusive with overlapping confidence intervals. Despite some limitations, the study provides useful data for this rare patient population