Heat Transfer on a Double Wedge Geometry in Hypervelocity Air and Nitrogen Flows

We investigate shock wave/boundary-layer interaction and resulting heat transfer in hypervelocity double wedge flows. An expansion tube is used to generate air and nitrogen flows with stagnation enthalpies ranging from 2.1-8.0 MJ/kg and Mach numbers from 4-7. The range of free stream conditions were selected to investigate the impact of thermochemical effects by i) systematically varying the chemical composition from nitrogen to air while maintaining constant the stagnation enthalpy or the Mach number, and ii) varying the stagnation enthalpy. Flow features are visualized with schlieren photography, and heat transfer is measured using fast response coaxial thermocouples. Data are presented for both nitrogen and air test conditions with eight cases in total. Current results indicate significantly different behavior in flows with enthalpies as low as 4 MJ/kg between air and nitrogen test conditions

Athletes Perceive Weighted Baseballs to Carry a Notable Injury Risk, yet Still Use Them Frequently: A Multicenter Survey Study

INTRODUCTION: Weighted baseball use in throwing programs is widespread; however, their use remains controversial. Prior research shows that weighted baseball programs can increase ball velocity but potentially increase throwing arm injuries. This study aims to ascertain perceptions of weighted baseballs among elite baseball players. METHODS: A created online survey questioned common practices, throwing regimens, injury risk factors, and weighted baseball program use. The questions were modeled to ascertain the perceptions of elite baseball players to understand their experience with weighted baseballs. Descriptive statistical analysis was conducted. RESULTS: Three hundred seventy-six baseball players with a mean age of 20 ± 2 years completed the survey; 64% of the players (239/376) were pitchers. 71% (267/376) reported the use of weighted baseballs. Of those, 75% (199/267) thought it made them a better player. Overall, 73% (275/377) thought weighted baseballs are a risk for injury. 17% (46/267) attributed their injury to using weighted baseballs. Overall, participants reported a mean 72% ± 30% likelihood of future weighted baseball use. CONCLUSION: Most of the participating elite adult baseball players reported prior weighted baseball use with a corresponding improvement in pitching performance despite a perceived increased injury risk. Nearly 20% of the players attributed pain or injury to weighted baseball use. Moreover, the players surveyed intend to continue using weighted baseballs because of the perceived performance benefit

Internal and near nozzle measurements of Engine Combustion Network "Spray G" gasoline direct injectors

[EN] Gasoline direct injection (GDI) sprays are complex multiphase flows. When compared to multi-hole diesel sprays, the plumes are closely spaced, and the sprays are more likely to interact. The effects of multi-jet interaction on entrainment and spray targeting can be influenced by small variations in the mass fluxes from the holes, which in turn depend on transients in the needle movement and small-scale details of the internal geometry. In this paper, we present a comprehensive overview of a multi-institutional effort to experimentally characterize the internal geometry and near-nozzle flow of the Engine Combustion Network (ECN) Spray G gasoline injector. In order to develop a complete pictitre of the near-nozzle flow, a standardized setup was shared between facilities. A wide range of techniques were employed, including both X-ray and visible-light diagnostics. The novel aspects of this work include both new experimental measurements, and a comparison of the results across different techniques and facilities. The breadth and depth of the data reveal phenomena which were not apparent from analysis of the individual data sets. We show that plume-to-plume variations in the mass fluxes from the holes can cause large-scale asymmetries in the entrainment field and spray structure. Both internal flow transients and small-scale geometric features can have an effect on the external flow. The sharp turning angle of the flow into the holes also causes an inward vectoring of the plumes relative to the hole drill angle, which increases with time due to entrainment of gas into a low-pressure region between the plumes. These factors increase the likelihood of spray collapse with longer injection durations.The X-ray experiments were performed at the 7-BM and 32-ID beam lines of the APS at Argonne National Laboratory. Use of the APS is supported by the U.S. Department of Energy (DOE) under Contract No. DE-AC02-06CH11357. Research was also performed at the Combustion Research Facility, Sandia National Laboratories, Livermore, California. Sandia National Laboratories is managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy National Nuclear Security Administration under contract DE-NA-0003525.Duke, DJ.; Kastengren, AL.; Matusik, KE.; Swantek, AB.; Powell, CF.; Payri, R.; Vaquerizo, D.... (2017). Internal and near nozzle measurements of Engine Combustion Network "Spray G" gasoline direct injectors. Experimental Thermal and Fluid Science. 88:608-621. https://doi.org/10.1016/j.expthermflusci.2017.07.015S6086218

Seletividade e absorção radicular do sulfentrazone em clones de eucalipto

O objetivo deste trabalho foi avaliar a seletividade e a absorção do sulfentrazone em clones de eucalipto. O primeiro experimento foi instalado em casa de vegetação, em delineamento inteiramente casualizado, com quatro repetições, no esquema fatorial 2 x 4, sendo duas doses do sulfentrazone (400 e 600 g ha-1) e quatro clones de eucalipto, híbridos de Eucalyptus grandis x E. urophylla (FB1, FB2, FB3 e FB4). Foram realizadas avaliações visuais de intoxicação das plantas de eucalipto e, no final do estudo, determinou-se a massa seca da parte aérea dos clones. No segundo experimento, foram utilizados os mesmos clones, sendo estes acondicionados em tubos falcon com 50 mL da solução contendo o sulfentrazone na concentração de 129 mM. As plantas de eucalipto permaneceram por 24 horas com as raízes imersas na solução e, em seguida, foi realizada a extração da seiva do xilema das plantas por meio de uma câmara de pressão. A concentração de sulfentrazone na seiva das plantas foi determinada através de cromatografia líquida e espectrometria de massas. O clone FB3 apresentou menor acúmulo de massa seca em relação aos demais, o que pode estar diretamente associado aos altos níveis de intoxicação observados. O clone FB2, apesar de mostrar elevada intoxicação, não apresentou níveis tão elevados de redução de massa seca em relação à testemunha. No tocante às concentrações de sulfentrazone nas plantas, elas foram proporcionais ao acúmulo de massa seca, o que indica que as variações na seletividade dos clones de eucalipto podem estar relacionadas à absorção diferenciada do herbicida.The objective of this work was to evaluate the selectivity and absorption of sulfentrazone in clones of eucalyptus. The first experiment was set up in a greenhouse in a completely randomized design in a factorial 2 x 4, with two rates of sulfentrazone (400 and 600 g ha-1) and four clones of eucalyptus, hybrids of Eucalyptus grandis x E. urophylla (FB1, FB2, FB3, FB4), with four replications. Visual evaluations of intoxication of the eucalyptus plants were carried out and the dry mass of the plants was determined at the end of the study. In the second experiment, the same clones of eucalyptus were placed in falcon tubes with 50 mL of sulfentrazone at a concentration of 129 Mm, remaining for 24 hours until the extraction of xylem sap plant through a pressure pump. The concentration of sulfentrazone in the sap of the plants was determined by liquid chromatography and mass spectrometry. Clone FB3 showed greater dry mass reduction in relation to the other clones, and this reduction can be directly associated with the high levels of phytotoxicity observed. Clone FB2 presented high levels of intoxication, but did not show high dry mass reduction. The concentrations of sulfentrazone absorbed by the plants were proportional to the reductions in dry mass, indicating that variations in the selective eucalyptus clones may be related to the differentiated absorption of the herbicide

Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) is required for lipopolysaccharide stimulation of tumor necrosis factor alpha (TNF-alpha) translation: glucocorticoids inhibit TNF-alpha translation by blocking JNK/SAPK.

The adverse effects of lipopolysaccharide (LPS) are mediated primarily by tumor necrosis factor alpha (TNF-alpha). TNF-alpha production by LPS-stimulated macrophages is regulated at the levels of both transcription and translation. It has previously been shown that several mitogen-activated protein kinases (MAPKs) are activated in response to LPS. We set out to determine which MAPK signaling pathways are activated in our system and which MAPK pathways are required for TNF-alpha gene transcription or TNF-alpha mRNA translation. We confirm activation of the MAPK family members extracellular-signal-regulated kinases 1 and 2 (ERK1 and ERK2), p38, and Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK), as well as activation of the immediate upstream MAPK activators MAPK/ERK kinases 1 and 4 (MEK1 and MEK4). We demonstrate that LPS also activates MEK2, MEK3, and MEK6. Furthermore, we demonstrate that dexamethasone, which inhibits the production of cytokines, including TNF-alpha, significantly inhibits LPS induction of JNK/SAPK activity but not that of p38, ERK1 and ERK2, or MEK3, MEK4, or MEK6. Dexamethasone also blocks the sorbitol but not anisomycin stimulation of JNK/SAPK activity. A kinase-defective mutant of SAPKbeta, SAPKbeta K-A, blocked translation of TNF-alpha, as determined by using a TNF-alpha translational reporting system. Finally, overexpression of wild-type SAPKbeta was able to overcome the dexamethasone-induced block of TNF-alpha translation. These data confirm that three MAPK family members and their upstream activators are stimulated by LPS and demonstrate that JNK/SAPK is required for LPS-induced translation of TNF-alpha mRNA. A novel mechanism by which dexamethasone inhibits translation of TNF-alpha is also revealed