1,098 research outputs found
Seismic forces and state power: the creation of the Chilean Seismological Service at the beginning of the twentieth century
In 1906, the Valparaíso earthquake marked a breakthrough in earthquake observation in Chile. During the nineteenth century, seismic observation was mostly a matter of concern to foreign travelers and scientists. Meanwhile, after the 1906 earthquake, seismic knowledge began to have greater importance for the state. The study of all tremors in the country responded to the demand to mitigate the vulnerability of the country facing the threat of earthquakes. For this task, the government of Chile created the Seismological Service, a national network of observatories and seismic stations, but also of observers. These observers helped to produce local seismic knowledge, tracing which places in the country were most frequently exposed to earthquakes
Gauge invariance in the presence of a cutoff
We use the method of gauging equations to construct the electromagnetic
current operator for the two-nucleon system in a theory with a finite cutoff.
The employed formulation ensures that the two-nucleon T-matrix and
corresponding five-point function, in the cutoff theory, are identical to the
ones formally defined by a reference theory without a cutoff. A feature of our
approach is that it effectively introduces a cutoff into the reference theory
in a way that maintains the long-range part of the exchange current operator;
for applications to effective field theory (EFT), this property is usually
sufficient to guarantee the predictive power of the resulting cutoff theory. In
addition, our approach leads to Ward-Takahashi (WT) identities that are linear
in the interactions.
From the point of view of EFT's where such a WT identity is satisfied in the
reference theory, this ensures that gauge invariance in the cutoff theory is
maintained order by order in the expansion.Comment: 15 pages, 2 figure
Renormalization of NN-Scattering with One Pion Exchange and Boundary Conditions
A non perturbative renormalization scheme for Nucleon-Nucleon interaction
based on boundary conditions at short distances is presented and applied to the
One Pion Exchange Potential. It is free of off-shell ambiguities and
ultraviolet divergences, provides finite results at any step of the calculation
and allows to remove the short distance cut-off in a suitable way. Low energy
constants and their non-perturbative evolution can directly be obtained from
experimental threshold parameters in a completely unique and model independent
way when the long range explicit pion effects are eliminated. This allows to
compute scattering phase shifts which are, by construction consistent with the
effective range expansion to a given order in the C.M. momentum . In the
singlet and triplet channels ultraviolet fixed points
and limit cycles are obtained respectively for the threshold parameters. Data
are described satisfactorily up to CM momenta of about .Comment: 22 pages, 10 figures, revte
Validation of multivariate calibration models in the determination of sugar cane quality parameters by near infrared spectroscopy
The determination of soluble solids (BRIX), polarizable sugars (POL) and reducing sugars (RS) sugar cane juice by using near infrared spectroscopy (NIR) and multivariate calibration was developed and validated by calculation of figures of merit. Due to the heterogeneity of the samples, first it was necessary to optimize the calibration set by outlier elimination. The figures of merit such as: sensitivity, analytical sensitivity, selectivity, confidence limit, precision (mean, repeatability), accuracy and signal-to-noise ratio were calculated. Feasible results were obtained for BRIX and POL with RMSEP values of 0.28 and 0.42% of juice and precision of 0.02 and 0.08% of juice, respectively. For both BRIX and POL goodness of fit showed correlation coefficients of 0.99. These results indicate that the models developed for BRIX and POL can be used as an alternative to standard procedures in the sugar cane industry.Os teores de sólidos solúveis (BRIX), açúcares polarizáveis (POL) e açúcares redutores (RS) em caldo de cana foram determinados utilizando espectroscopia na região do infravermelho próximo (NIR) e calibração multivariada, a qual foi validada pelo cálculo das figuras de mérito. Devido à heterogeneidade das amostras, foi necessário, como primeira etapa do trabalho, a otimização dos conjutos de calibração e validação através da eliminação das amostras anômalas (outliers). As figuras de mérito como: sensibilidade, sensibilidade analítica, seletividade, limites de confiança, precisão (média, repetibilidade), exatidão e razão sinal-ruído foram calculadas. Resultados viáveis foram obtidos para BRIX e POL apresentando resultados de RMSEP de 0,28 e 0,42% de caldo, respectivamente. Os coeficientes de correlação para ambos os parâmetros foram de 0,99. Estes resultados indicam que os modelos desenvolvidos para BRIX e POL podem ser seguramente utilizados como uma alternativa em relação ao método padrão utilizado na indústria alcooleira.259266Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
NADP-Dependent Isocitrate Dehydrogenase from Arabidopsis Roots Contributes in the Mechanism of Defence against the Nitro-Oxidative Stress Induced by Salinity
NADPH regeneration appears to be essential in the mechanism of plant defence against oxidative stress. Plants contain several NADPH-generating dehydrogenases including isocitrate dehydrogenase (NADP-ICDH), glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), and malic enzyme (ME). In Arabidopsis seedlings grown under salinity conditions (100 mM NaCl) the analysis of physiological parameters, antioxidant enzymes (catalase and superoxide dismutase) and content of superoxide radical (O2 ∙−), nitric oxide (NO), and peroxynitrite (ONOO−) indicates a process of nitro-oxidative stress induced by NaCl. Among the analysed NADPH-generating dehydrogenases under salinity conditions, the NADP-ICDH showed the maximum activity mainly attributable to the root NADP-ICDH. Thus, these data provide new insights on the relevance of the NADP-ICDH which could be considered as a second barrier in the mechanism of response against the nitro-oxidative stress generated by salinity
Renormalization of Singular Potentials and Power Counting
We use a toy model to illustrate how to build effective theories for singular
potentials. We consider a central attractive 1/r^2 potential perturbed by a
1/r^4 correction. The power-counting rule, an important ingredient of effective
theory, is established by seeking the minimum set of short-range counterterms
that renormalize the scattering amplitude. We show that leading-order
counterterms are needed in all partial waves where the potential overcomes the
centrifugal barrier, and that the additional counterterms at next-to-leading
order are the ones expected on the basis of dimensional analysis.Comment: 23 pages, 6 figure
Enhanced monography in a collaboratively evolved hub for systematic biology
No abstract available
Hydrodynamic Analysis of a Wave Energy Converter (WEC)
Honorable Mention Winner
The UNF CREW competing in the U.S. Department of Energy 2021 Marine Energy Collegiate Competition developed a Wave Energy Converter (WEC) for quick deployment in disaster relief areas. When natural disasters disable coastal power grids, a WEC can be easily deployed close to shore and serve as a source of electricity. The ocean waves move magnets through a coil wired within the WEC to generate electricity. To initiate the design process, ANSYS AQWA software simulated both the oceanic environment and the device’s response in the WEC’s testing conditions. AQWA allows the user to change device dimensions easily and optimize the design ahead of physical construction. The resulting WEC proof of concept minimized prototype manufacturing waste and cost by eliminating poor designs in advance. The simulated geometry neglected hollow sections and used unidirectional, regular waves to account for software limitations. The software simulated the WEC for 20 seconds in an oceanic environment with a 40-meter depth and a 0.25-meter amplitude regular wave. Simulations produced graphs and animations describing the forces acting on the WEC as well as the WEC’s movement. The animation proved that the WEC reacts well in similar physical testing conditions. Based on the simulation results, the team constructed a 3D model for small-scale testing. Future investigations will involve more complex designs. Research conducted onward will focus on mass-damper systems and contact surfaces provided in the software
Optimization of Power Performance of a Wave Energy Converter
With climate change on the rise, unprecedented dependence on electricity, and an increased incidence of extreme weather, the UNF team participating in the U.S. Department of Energy 2021 Marine Energy Collegiate Competition: Powering the Blue Economy wants to give an alternative solution to provide renewable energy in areas that lose electricity as a result of a natural disaster, or that due to their isolated location cannot use traditional renewable energy sources. This led to the creation of the Osprey C.R.E.W (Cheap Reliable Energy from Waves). The Osprey C.R.E.W. is a wave energy converter that uses the vertical motion of the ocean waves to generate electricity. The principle of energy conversion is Faraday’s Law of Electromagnetic Induction, which states that a magnetic field moving past a conductor will generate electricity. The UNF team has developed a numerical simulation to test how different parameters influence the output and has built three small-scale prototypes that have been tested in a wave tank. A medium-sized prototype and a wave pool are being constructed, with the expectation that the size will also increase the output
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