4,858 research outputs found
Some comments on particle image displacement velocimetry
Laser speckle velocimetry (LSV) or particle image displacement velocimetry, is introduced. This technique provides the simultaneous visualization of the two-dimensional streamline pattern in unsteady flows as well as the quantification of the velocity field over an entire plane. The advantage of this technique is that the velocity field can be measured over an entire plane of the flow field simultaneously, with accuracy and spatial resolution. From this the instantaneous vorticity field can be easily obtained. This constitutes a great asset for the study of a variety of flows that evolve stochastically in both space and time. The basic concept of LSV; methods of data acquisition and reduction, examples of its use, and parameters that affect its utilization are described
The development of laser speckle or particle image displacement velocimetry. Part 1: The role of photographic parameters
One of the difficult problems in experimental fluid dynamics remains the determination of the vorticity field in fluid flows. Recently, a novel velocity measurement technique, commonly known as Laser Speckle or Particle Image Displacement Velocimetry became available. This technique permits the simultaneous visualization of the 2 dimensional streamline pattern in unsteady flows and the quantification of the velocity field. The main advantage of this new technique is that the whole 2 dimensional velocity field can be recorded with great accuracy and spatial resolution, from which the instantaneous vorticity field can be easily obtained. A apparatus used for taking particle displacement images is described. Local coherent illumination by the probe laser beam yielded Young's fringes of good quality at almost every location of the flow field. These fringes were analyzed and the velocity and vorticity fields were derived. Several conclusions drawn are discussed
Avaliação da produção de biomassa vegetal de quatro espécies visando a melhoria do solo de vegetação secundária na Amazônia Central.
Buscando técnicas inovadoras e sustentáveis para serem usadas na agricultura como forma de deixar o solo mais fértil e recuperar áreas modificadas, o presente trabalho foi realizado. No período de janeiro de 2011 a março de 2012, foram inseridas e monitoradas junto à capoeira no Campo Experimental da Embrapa Amazônia Ocidental km 29, quatro espécies vegetais conhecidas da Amazônia, (Tefrosia candida, Flemingia macrophyla, Bixa orellana e Inga edulis), tais espécies apresentam um grande potencial de acúmulo de biomassa e nutrientes
The effect of photoperiod and seasonal changes in the food intake of tropical fish, Orechromis niloticus.
The influence of photoperiod in the growth and weight gain in nile tilapia, Oreochromis niloticus, under constant temperature in two seasons.
J/\Psi production, polarization and Color Fluctuations
The hard contributions to the heavy quarkonium-nucleon cross sections are
calculated based on the QCD factorization theorem and the nonrelativistic
quarkonium model. We evaluate the nonperturbative part of these cross sections
which dominates at GeV at the Cern Super Proton
Synchrotron (SPS) and becomes a correction at TeV at
the CERN Large Hadron Collider (LHC). \J production at the CERN SPS is well
described by hard QCD, when the larger absorption cross sections of the
states predicted by QCD are taken into account. We predict an -dependent
polarization of the states. The expansion of small wave packets is
discussed.Comment: 13 pages REVTEX, 1 table, 2 PostScript, corrected some typo
The clinical effectiveness of transurethral incision of the prostate : a systematic review of randomised controlled trials
The original publication is available at www.springerlink.com.Peer reviewedPostprin
A Review on Multi-Terminal High Voltage Direct Current Networks for Wind Power Integration
With the growing pressure to substitute fossil fuel-based generation, Renewable Energy Sources (RES) have become one of the main solutions from the power sector in the fight against climate change. Offshore wind farms, for example, are an interesting alternative to increase renewable power production, but they represent a challenge when being interconnected to the grid, since new installations are being pushed further off the coast due to noise and visual pollution restrictions. In this context, Multi-Terminal High Voltage Direct Current (MT-HVDC) networks are the most preferred technology for this purpose and for onshore grid reinforcements. They also enable the delivery of power from the shore to offshore Oil and Gas (O&G) production platforms, which can help lower the emissions in the transition away from fossil fuels. In this work, we review relevant aspects of the operation and control of MT-HVDC networks for wind power integration. The review approaches topics such as the main characteristics of MT-HVDC projects under discussion/commissioned around the world, rising challenges in the control and the operation of MT-HVDC networks and the modeling and the control of the Modular Multilevel Converter (MMC) stations. To illustrate the challenges on designing the control system of a MT-HVDC network and to corroborate the technical discussions, a simulation of a three-terminal MT-HVDC network integrating wind power generation and offshore O&G production units to the onshore grid is performed in Matlab's Simscape Electrical toolbox. The results highlight the main differences between two alternatives to design the control system for an MT-HVDC network
Association between genetic polymorphisms in apoptosis-related genes and risk of cutaneous melanoma in women and men
The P53 Arg72Pro, MDM2 c.+309T > G, BAX c.-248G > A, and BCL2 c.-717C > A polymorphisms have variable roles in the apoptosis pathways. The P53 Arg72Pro, MDM2 c.+309T > G, BAX c.-248G > A, and BCL2 c.-717C > A polymorphisms have variable roles in the apoptosis pathways. Genomic DNA of 200 CM patients and 215 controls was analyzed by PCR-RFLP. In women, the frequencies of BAX GG (83.0% vs. 71.0%, P = 0.04), BM AA (32.0% vs. 15.0%, P = 0.003), P53 ArgArg plus BAX GG (84.9% vs. 63.2%, P = 0.01), P53 ArgArg plus BCL2 AA (37.0% vs. 13.1%, P = 0.003), BAX GG plus BCL2 AA (70.3% vs. 33.3%, P = 0.001), MDM2 GG plus BAX GG plus BCL2 AA (27.3% vs. 3.7%, P = 0.03), and P53 ArgArg plus MDM2 GG plus BAX GG plus BCL2 AA (33.3% vs. 5.6%, P = 0.04) genotypes were higher in patients than in controls. Female carriers of the respective genotypes were under 1.98 (95% CI: 1.01-3.91), 2.87 (95% CI: 1.43-5.77), 3.48 (95% CI: 1.34-9.04), 4.23 (95% CI: 1.63-10.96), 6.04 (95% CI: 2.10-17.37), 25.61 (95% CI: 1.29-507.24), and 25.69 (95% CI: 1.11-593.59)-fold increased risks for CM than others, respectively. In men, the frequencies of BCL2 CA + AA (83.0% vs. 67.6%, P = 0.01) and MDM2 TG + GG plus BCL2 CA + AA (94.2% vs. 68.3%, P = 0.003) genotypes were higher in patients than in controls. Male carriers of the respective genotypes were under 2.43 (95% CI: 1.23-4.82) and 9.22 (95% CI: 2.16-39.31)-fold increased CM risks than others, respectively. The data suggest for the first time that P53 Arg72Pro, MDM2 c.+309T > G, BAX c.-248G > A, and BCL2 c.-717C > A polymorphisms, enrolled in apoptosis pathways, constitute distinct determinants of CM in women and men742135141FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2009/12602-0; 2010/18904-
Comportamento sazonal na ingestão de alimentos e ganho de peso em tilápias do Nilo Oreochromis niloticus sob o efeito de dois fotoperíodos.
Avaliacao do comportamento sazonal na nutricao da tilapia do Nilo, sob dois fotoperiodos
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