The near wall effect of synthetic jets in a boundary layer

Copyright @ 2007 Elsevier Inc. All rights reserved.An experimental investigation to analyse the qualitative near wall effect of synthetic jets in a laminar boundary layer has been undertaken for the purpose of identifying the types of vortical structures likely to have delayed separation on a 2D circular cylinder model described in this paper. In the first instance, dye visualisation of the synthetic jet was facilitated in conjunction with a stereoscopic imaging system to provide a unique quasi three-dimensional identification of the vortical structures. Secondly, the impact of synthetic jet structures along the wall was analysed using a thermochromic liquid crystal-based convective heat transfer sensing system in which, liquid crystals change colour in response to the thermal footprints of a passing flow structure. Of the different vortical structures produced as a result of varying actuator operating and freestream conditions, the footprints of hairpin vortices and stretched vortex rings revealed a marked similarity with the oil flow pattern of a vortex pair interacting with the separation line on the cylinder hence suggesting that either of these structures was responsible in delaying separation. Conditions were established for the formation of the different synthetic jet structures in non-dimensional parameter space

Patient-level meta-analysis of the EDITION 1, 2 and 3 studies : glycaemic control and hypoglycaemia with new insulin glargine 300 U/ml versus glargine 100 U/ml in people with type 2 diabetes

AimsTo conduct a patient-level meta-analysis of the EDITION 1, 2 and 3 studies, which compared the efficacy and safety of new insulin glargine 300 U/ml (Gla-300) with insulin glargine 100 U/ml (Gla-100) in people with type 2 diabetes (T2DM) on basal and mealtime insulin, basal insulin and oral antihyperglycaemic drugs, or no prior insulin, respectively. MethodsThe EDITION studies were multicentre, randomized, open-label, parallel-group, phase IIIa studies, with similar designs and endpoints. A patient-level meta-analysis of the studies enabled these endpoints to be examined over 6 months in a large population with T2DM (Gla-300, n = 1247; Gla-100, n = 1249). ResultsNo significant study-by-treatment interactions across studies were found, enabling them to be pooled. The mean change in glycated haemoglobin was comparable for Gla-300 and Gla-100 [each -1.02 (standard error 0.03)%; least squares (LS) mean difference 0.00 (95% confidence interval (CI) -0.08 to 0.07)%]. Annualized rates of confirmed (3.9 mmol/l) or severe hypoglycaemia were lower with Gla-300 than with Gla-100 during the night (31% difference in rate ratio over 6 months) and at any time (24 h, 14% difference). Consistent reductions were observed in percentage of participants with 1 hypoglycaemic event. Severe hypoglycaemia at any time (24 h) was rare (Gla-300: 2.3%; Gla-100: 2.6%). Weight gain was low ( ConclusionGla-300 provides comparable glycaemic control to Gla-100 in a large population with a broad clinical spectrum of T2DM, with consistently less hypoglycaemia at any time of day and less nocturnal hypoglycaemia.Peer reviewe

A pattern matching technique for measuring sediment displacement levels

This paper describes a novel technique for obtaining accurate, high (spatial) resolution measurements of sediment redeposition levels. A sequence of different random patterns are projected onto a sediment layer and captured using a high-resolution camera, producing a set of reference images. The same patterns are used to obtain a corresponding sequence of deformed images after a region of the sediment layer has been displaced and redeposited, allowing the use of a high-accuracy pattern matching algorithm to quantify the distribution of the redeposited sediment. A set of experiments using the impact of a vortex ring with a glass ballotini particle layer as the resuspension mechanism are described to test and illustrate the technique. The accuracy of the procedure is assessed using a known crater profile, manufactured to simulate the features of the craters observed in the experiments

DIRECTIONS FOR SUSTAINABILITY: I. ALTERNATIVE ENERGY

Concern with the future of planet Earth, its sustainability and conservation of life (both human and of the several species) has resulted in several debates and socioeconomic changes in the past decades. The ongoing and systematic gas emission (especially CO2) arising out of the growing need for energy for the many social sectors has been blamed as the main villain in this story. Is it possible to go back in time and recover nature’s balance without giving up the technologies that improved the quality of life of most people in the past century? How can we control nature’s fury, consequence of the many climate changes? Answers are to be found in collaboration, once the awareness of each individual is raised via simple and clear information concerning the phenomena involved, the technology available and to be developed. In view of the above, Parque CienTec, the Science and Technology Park of the University of São Paulo, created exhibits in scale and promotes monitored activities on the type and use of the alternative energies and how to put them into practice. This study is part of a larger project involving biological sciences and social activities.Nas últimas décadas, a grande preocupação com o futuro do planeta Terra, sua sustentabilidade e a conservação da vida humana e das várias espécies, tem provocado variadas discussões e propostas de mudanças sociais e econômicas. Como principal vilã dessa história, foi eleita a intensa e contínua emissão de gases (principalmente CO2) derivada da crescente necessidade de energia pelos diversos segmentos sociais. Como retroagir no tempo para recuperar o equilíbrio da natureza sem abrir mão das tecnologias que melhoraram a qualidade de vida da maioria das populações no último século? Como estancar a fúria da natureza provocada pelas mudanças climáticas? As respostas encontram-se na colaboração após a conscientização de cada indivíduo através da informação simples e clara dos fenômenos envolvidos e das tecnologias já disponíveis e a serem desenvolvidas. Neste intuito, o Parque CienTec criou peças de exposição em escala real e promove atividades monitoradas sobre o tipo e uso de energias alternativas, de forma interativa e lúdica, para todas as idades e formações. Após um breve histórico, apresentam-se a seguir algumas alternativas e a forma de colocá-las em prática. O presente trabalho é parte de um projeto maior que envolve ciências biológicas e atividades sociais.

The Sunyaev-Zel'dovich Infrared Experiment: A Millimeter-wave Receiver for Cluster Cosmology

Measurements of the Sunyaev-Zel'dovich (S-Z) effect towards distant clusters of galaxies can be used to determine the Hubble constant and the radial component of cluster peculiar velocities. Determination of the cluster peculiar velocity requires the separation of the two components of the S-Z effect, which are due to the thermal and bulk velocities of the intracluster plasma. The two components can be separated practically only at millimeter (mm) wavelengths. Measurements of the S-Z effect at mm wavelengths are subject to minimal astrophysical confusion and, therefore, provide an important test of results obtained at longer wavelengths. We describe the instrument used to make the first significant detections of the S-Z effect at millimeter wavelengths. This instrument employs new filter, detector, and readout technologies to produce sensitive measurements of differential sky brightness stable on long time scales. These advances allow drift scan observations which achieve high sensitivity while minimizing common sources of systematic error.Comment: 19 pages, 15 postscript figures, LaTeX(aaspptwo.sty), ApJ(in press

Confinement of fractional excitations in a triangular lattice antiferromagnet

High-resolution neutron and THz spectroscopies are used to study the magnetic excitation spectrum of Cs$_2$CoBr$_4$, a distorted-triangular-lattice antiferromagnet with nearly XY-type anisotropy. What was previously thought of as a broad excitation continuum [Phys. Rev. Lett. 129, 087201 (2022)] is shown to be a series of dispersive bound states reminiscent of "Zeeman ladders" in quasi-one-dimensional Ising systems. At wave vectors where inter-chain interactions cancel at the Mean Field level, they can indeed be interpreted as bound finite-width kinks in individual chains. Elsewhere in the Brillouin zone their true two-dimensional structure and propagation are revealed.Comment: 11 pages, 8 figure

Genes Involved in the Balance between Neuronal Survival and Death during Inflammation

Glucocorticoids are potent regulators of the innate immune response, and alteration in this inhibitory feedback has detrimental consequences for the neural tissue. This study profiled and investigated functionally candidate genes mediating this switch between cell survival and death during an acute inflammatory reaction subsequent to the absence of glucocorticoid signaling. Oligonucleotide microarray analysis revealed that following lipopolysaccharide (LPS) intracerebral administration at striatum level, more modulated genes presented transcription impairment than exacerbation upon glucocorticoid receptor blockage. Among impaired genes we identified ceruloplasmin (Cp), which plays a key role in iron metabolism and is implicated in a neurodegenative disease. Microglial and endothelial induction of Cp is a natural neuroprotective mechanism during inflammation, because Cp-deficient mice exhibited increased iron accumulation and demyelination when exposed to LPS and neurovascular reactivity to pneumococcal meningitis. This study has identified genes that can play a critical role in programming the innate immune response, helping to clarify the mechanisms leading to protection or damage during inflammatory conditions in the CNS

Three-dimensional femtosecond laser nanolithography of crystals

Nanostructuring hard optical crystals has so far been exclusively feasible at their surface, as stress induced crack formation and propagation has rendered high precision volume processes ineffective. We show that the inner chemical etching reactivity of a crystal can be enhanced at the nanoscale by more than five orders of magnitude by means of direct laser writing. The process allows to produce cm-scale arbitrary three-dimensional nanostructures with 100 nm feature sizes inside large crystals in absence of brittle fracture. To showcase the unique potential of the technique, we fabricate photonic structures such as sub-wavelength diffraction gratings and nanostructured optical waveguides capable of sustaining sub-wavelength propagating modes inside yttrium aluminum garnet crystals. This technique could enable the transfer of concepts from nanophotonics to the fields of solid state lasers and crystal optics.Comment: Submitted Manuscript and Supplementary Informatio