Steep gravity–capillary waves within the internal resonance regime

Steep gravity–capillary waves are studied experimentally in a channel. The range of cyclic frequencies investigated is 6.94–9.80 Hz; namely, the high‐frequency portion of the regime of internal resonances according to the weakly nonlinear theory (Wilton’s ripples). These wave trains are stable according to the nonlinear Schrödinger equation. The experimental wave trains are generated by large, sinusoidal oscillations of the wavemaker. A comparison is made between the measured wave fields and the (symmetric) numerical solutions of Schwartz and Vanden‐Broeck [J. Fluid Mech. 95, 119 (1979)], Chen and Saffman [Stud. Appl. Math. 60, 183 (1979); 62, 95 (1980)], and Huh (Ph.D. dissertation, University of Michigan, 1991). The waves are shown to be of slightly varying asymmetry as they propagate downstream. Their symmetric parts, isolated by determining the phase which provides the smallest mean‐square antisymmetric part, compare favorably with the ‘‘gravity‐type’’ wave solutions determined by numerical computations. The antisymmetric part of the wave profile is always less than 30% of the peak‐to‐peak height of the symmetric part. As nonlinearity is increased, the amplitudes of the short‐wave undulations in the trough of the primary wave increase; however, there are no significant changes in these short‐wave frequencies. The lowest frequency primary‐wave experiments, which generate the highest frequency short‐wave undulations, exhibit more rapid viscous decay of these high‐frequency waves than do the higher‐frequency primary wave experiments.  Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69701/2/PFADEB-4-11-2466-1.pd

Land Subsidence Caused by Groundwater Exploitation in Yunlin, Taiwan

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

International Roundtable on the Future of Technology Education

No abstract available

International Roundtable on the Future of Technology Education

No abstract available

Molecular signature of clinical severity in recovering patients with severe acute respiratory syndrome coronavirus (SARS-CoV)

BACKGROUND: Severe acute respiratory syndrome (SARS), a recent epidemic human disease, is caused by a novel coronavirus (SARS-CoV). First reported in Asia, SARS quickly spread worldwide through international travelling. As of July 2003, the World Health Organization reported a total of 8,437 people afflicted with SARS with a 9.6% mortality rate. Although immunopathological damages may account for the severity of respiratory distress, little is known about how the genome-wide gene expression of the host changes under the attack of SARS-CoV. RESULTS: Based on changes in gene expression of peripheral blood, we identified 52 signature genes that accurately discriminated acute SARS patients from non-SARS controls. While a general suppression of gene expression predominated in SARS-infected blood, several genes including those involved in innate immunity, such as defensins and eosinophil-derived neurotoxin, were upregulated. Instead of employing clustering methods, we ranked the severity of recovering SARS patients by generalized associate plots (GAP) according to the expression profiles of 52 signature genes. Through this method, we discovered a smooth transition pattern of severity from normal controls to acute SARS patients. The rank of SARS severity was significantly correlated with the recovery period (in days) and with the clinical pulmonary infection score. CONCLUSION: The use of the GAP approach has proved useful in analyzing the complexity and continuity of biological systems. The severity rank derived from the global expression profile of significantly regulated genes in patients may be useful for further elucidating the pathophysiology of their disease

Oncologic impact of delay between diagnosis and radical nephroureterectomy

PurposeThis study aimed to evaluate the oncological outcome of delayed surgical wait time from the diagnosis of upper tract urothelial carcinoma (UTUC) to radical nephroureterectomy (RNU).MethodsIn this multicenter retrospective study, medical records were collected between 1988 and 2021 from 18 participating Taiwanese hospitals under the Taiwan UTUC Collaboration Group. Patients were dichotomized into the early (≤90 days) and late (>90 days) surgical wait-time groups. Overall survival, disease-free survival, and bladder recurrence-free survival were calculated using the Kaplan–Meier method and multivariate Cox regression analysis. Multivariate analysis was performed using stepwise linear regression.ResultsOf the 1251 patients, 1181 (94.4%) were classifed into the early surgical wait-time group and 70 (5.6%) into the late surgical wait-time group. The median surgical wait time was 21 days, and the median follow-up was 59.5 months. Our study showed delay-time more than 90 days appeared to be associated with worse overall survival (hazard ratio [HR] 1.974, 95% confidence interval [CI] 1.166−3.343, p = 0.011), and disease-free survival (HR 1.997, 95% CI 1.137−3.507, p = 0.016). This remained as an independent prognostic factor after other confounding factors were adjusted. Age, ECOG performance status, Charlson Comorbidity Index (CCI), surgical margin, tumor location and adjuvant systemic therapy were independent prognostic factors for overall survival. Tumor location and adjuvant systemic therapy were also independent prognostic factors for disease-free survival.ConclusionsFor patients with UTUC undergoing RNU, the surgical wait time should be minimized to less than 90 days. Prolonged delay times may be associated with poor overall and disease-free survival

Boundary conditions in the vicinity of the contact line at a vertically oscillating plate: An experimental investigation.

To determine a suitable boundary-condition model for the contact line in oscillatory flow, a vertical plate oscillated sinusoidally in dye-laden water with an air interface is considered experimentally. Constrained by the desirability of a two-dimensional flow field and the laboratory facility, eight individual frequencies (1 to 20 Hz) each with seven different stroke amplitudes (0.5 to 6 mm) are chosen for the experimental program. The corresponding Reynolds number for each experiments varies from 1.6 to 1878.3 which is large relative to the Reynolds number in the conventional uni-directional contact-line experiments (e.g. Dussan V.'s (1974) experiments). To facilitate prediction, a high-speed video system is used to record the plate displacement, the contact-line displacement, and the dynamic behavior of the contact angle. A particle-tracking-velocimetry (PTV) technique is used to detect particle trajectories near the plate such that the boundary condition along the entire plate can be modeled. Two sets of PTV experiments are conducted. One experiment is for the stick contact-line motion, the other experiment is for the stick-slip contact-line motion. Several interesting measured contact-line phenomena are shown in the present results. Several models are developed to explain these complicated phenomena. These models explain the contact-line and contact-angle behaviors well. An expression for $\lambda$, the dimensionless capillary coefficient (nondimensionalized by the maximum plate velocity), is formulated such that the dynamic behavior at the contact line is predicted accurately. The results from the PTV experiments show that a vortex is formed near the meniscus in the stick-slip contact-line experiment; however, in the stick contact-line experiment, no such vortex is present. Using the present experimental results, a model is developed for the boundary condition along the vertically oscillating plate. That is, slip occurs within a specific distance from the contact line while the flow obeys the no-slip condition outside this slip region. This model is more realistic and accurate than models based upon modified, uni-directional contact-line boundary-condition formulations.Ph.D.Applied SciencesMechanical engineeringMechanicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/129391/2/9501051.pd