Rotordynamic Forces from Discharge-to-Suction Leakage Flows in Centrifugal Pumps: Effects of Geometry

The rotordynamic forces generated by the fluid flow through the impeller leakage path of a centrifugal pump are now well established. The present paper examines the effects of modifying the leakage path geometry by changing the front shroud, from a conical shape to a more typical curved design, and the effects of low pressure seal design on these forces. It is found that only the cross-coupled stiffness is affected by the change of path geometry. Changing the low pressure seal from an axial to a radial clearance does, however, significantly affect the rotordynamic forces. A bulk flow numerical model is found to predict the same general result for the low pressure seal tests. The model agrees with the general trends with increasing leakage flow coefficient exhibited by the data, but appears to underpredict the magnitude of the normal force

Financial Markets, Public Policy, and the East Asian Miracle

Many factors contributed to the rapid growth of the economies of East Asia in the past quarter century. This article examines one important aspect of that growth--commonly referred to as the "East Asian miracle"--public policies affecting the financial markets. East Asian governments intervened extensively in financial markets at all stages of their development. What sets their actions apart from those of other developing countries that have not fared as well? We do not have the information to answer conclusively what effect particular actions had (that requires a counterfactual test of what growth would have been without the particular intervention). But we can identify the market failures the East Asian governments addressed, assess some of the theoretical reasons why each policy might be growth enhancing, and provide some data attesting to the impacts of the policy. Several characteristics of financial sector interventions in East Asia stand out: they incorporated design features that improved the chances of success and reduced opportunities for abuse; interventions that did not work out were dropped unhesitatingly; and policies were adapted to reflect changing economic conditions

CPX-351 (cytarabine and daunorubicin) liposome for injection versus conventional cytarabine plus daunorubicin in older patients with newly diagnosed secondary acute myeloid leukemia

Purpose CPX-351 is a dual-drug liposomal encapsulation of cytarabine and daunorubicin that delivers a synergistic 5:1 drug ratio into leukemia cells to a greater extent than normal bone marrow cells. Prior clinical studies demonstrated a sustained drug ratio and exposure in vivo and prolonged survival versus standard-of-care cytarabine plus daunorubicin chemotherapy (7+3 regimen) in older patients with newly diagnosed secondary acute myeloid leukemia (sAML). Patients and Methods In this open-label, randomized, phase III trial, 309 patients age 60 to 75 years with newly diagnosed high-risk/sAML received one to two induction cycles of CPX-351 or 7+3 followed by consolidation therapy with a similar regimen. The primary end point was overall survival. Results CPX-351 significantly improved median overall survival versus 7+3 (9.56 v 5.95 months; hazard ratio, 0.69; 95% CI, 0.52 to 0.90; one-sided P = .003). Overall remission rate was also significantly higher with CPX-351 versus 7+3 (47.7% v 33.3%; two-sided P = .016). Improved outcomes were observed across age-groups and AML subtypes. The incidences of nonhematologic adverse events were comparable between arms, despite a longer treatment phase and prolonged time to neutrophil and platelet count recovery with CPX-351. Early mortality rates with CPX-351 and 7+3 were 5.9% and 10.6% (two-sided P = .149) through day 30 and 13.7% and 21.2% (two-sided P = .097) through day 60. Conclusion CPX-351 treatment is associated with significantly longer survival compared with conventional 7+3 in older adults with newly diagnosed sAML. The safety profile of CPX-351 was similar to that of conventional 7+3 therapy

A Parametric Evaluation of the Effect of Inlet Swirl on the Rotordynamic Forces Generated by Discharge-to-Suction Leakage Flows in Shrouded Centrifugal Pumps

Unsteady forces generated by the fluid flow through the impeller leakage path of a centrifugal pump were investigated. The effect of leakage path inlet (pump discharge) swirl on the rotordynamic forces was examined for various ratios of fluid tangential velocity to impeller tip speed. It was observed that changing the inlet swirl velocity does not appear to significantly affect the measured forces for a given leakage flow coefficient. A bulk flow numerical model was found to predict the same general result. The model agreed with experimental data for small values of the leakage flow coefficient

Editor\u27s Introduction to the 10th Anniversary Volume of the Journal of Southeast Asian American Education and Advancement

Editor\u27s Introduction to the 10th Anniversary Volum

A Powerful and Computationally Efficient Algorithm for Transmission Loss Calculation

This paper deals with the formulation of transmission loss PL of a power system through a set of new coefficients (A coefficients) which are extremely efficient, exact and robust and suitable for real time application. Results on a few IEEE test systems are exciting and encouraging. They demonstrate that these A coefficients faithfully represent the system loss, are extremely robust and need not be re-evaluated for changes in the system loading conditions either for evaluation of system loss or cost of generation for economic load dispatch

Expression of Sox family genes in early lamprey development

Members of the Sox (Sry-related high mobility group box) family of transcription factors play a variety of roles during development of both vertebrates and invertebrates. A marked expansion in gene number occurred during the emergence of vertebrates, apparently via gene duplication events that are thought to have facilitated new functions. By screening a macroarrayed library as well as the lamprey genome, we have isolated genes of the Sox B, D, E and F subfamilies in the basal jawless vertebrate, lamprey. The expression patterns of all identified Sox genes were examined from gastrulation through early organogenesis (embryonic day 4-14), with particular emphasis on the neural crest, a vertebrate innovation. Coupled with phylogenetic analysis of these Sox genes, the results provide insight into gene duplication and divergence in paralog deployment occurring during early vertebrate evolution

Perceptions of Self-Efficacy & Support Among Secondary Early-Career Teachers and their Principals During the COVID-19 Pandemic

In response to challenges faced by middle and high school educators during the COVID-19 pandemic, a study was conducted in the Spring of 2021 involving 33 early-career mathematics teachers and eight supervising school principals in the State of California. These participants completed detailed surveys which provided demographic information, as well as perceptions of support, efficacy and job satisfaction. Findings show a variety of associations among teacher perceptions of support and their efficacy and job satisfaction in the face of challenging circumstances. As it related to principal support and recognition, principal participants expressed confidence in their ability to support teachers as a result of the pandemic, including understanding best practices for evaluating teachers for online teaching. Additionally, while agreeing that teachers at their schools needed more professional development in instructional practice, participating school principals felt they supported their teachers as they adapted instruction due to the COVID-19 pandemic. This study aspires to inform practitioners and policymakers alike in their understanding of teachers and their principals as they responded to significant challenges as a result of the COVID-19 pandemic

Difference in Plumage Color Used in Species Recognition between Incipient Species Is Linked to a Single Amino Acid Substitution in the Melanocortin‐1 Receptor

This is the publisher's version, also available electronically from http://www.jstor.org/stable/10.1086/600084Many studies demonstrate that differences in mating signals are used by incipient species in recognizing potential mates or sexual competitors (i.e., species recognition). Little is known, however, about the genetic changes responsible for these differences in mating signals. Populations of the Monarcha castaneiventris flycatcher vary in plumage color across the Solomon Islands, with a subspecies on Makira Island having chestnut bellies and blue‐black upper parts (Monarcha castaneiventris megarhynchus) and a subspecies on neighboring satellite islands being entirely blue‐black (melanic; Monarcha castaneiventris ugiensis). Here we show that a single nonsynonymous point mutation in the melanocortin‐1 receptor (MC1R) gene is present in all melanic birds from one island (Santa Ana) but absent in all chestnut‐bellied birds from Makira Island, implicating this mutation in causing melanism. Birds from a second satellite island (Ugi) do not show the same perfect association between this MC1R variant and plumage color, suggesting an alternative mechanism for melanism on this island. Finally, taxidermic mount presentation experiments in Makira (chestnut) and Santa Ana (melanic) suggest that the plumage difference mediates species recognition. Assuming that the signals used in species recognition are also used in mutual mate choice, our results indicate that a single amino acid substitution contributes to speciation