Produção Nacional
Jane Cruz Prates, Flávio Cruz Prates, Simone Machado,
O presente artigo problematiza os processos de exclusão e inclusão precária a que estão sujeitos pessoas que vivem nas ruas dos grandes centros urbanos, marcados por processos de discriminação e estigmas, não só de parte da sociedade em geral, mas também daqueles que, a partir da oferta de serviços públicos, deveriam buscar a garantia de seus direitos. Aborda a realidade dos sujeitos em situação de rua a partir de dados nacionais e internacionais que dão visibilidade a suas características e condições ...
Tópico(s): Urban and sociocultural dynamics
2012 - | Temporalis
Flávio Cruz, Andreas Moser, Michael Cohen,
In the field of remote forensics, the GRR Response Rig has been used to access and store data from thousands of enterprise machines. Handling large numbers of machines requires efficient and scalable storage mechanisms that allow concurrent data operations and efficient data access, independent of the size of the stored data and the number of machines in the network. We studied the available GRR storage mechanisms and found them lacking in both speed and scalability. In this paper, we propose a ...
Tópico(s): Advanced Malware Detection Techniques
2015 - Elsevier BV | Digital Investigation
Produção Nacional
Revisado por pares
Gustavo Vinagre, Flávio Cruz, Khalid Alkhelaifi, Pieter D’Hooghe,
The prevalence of isolated meniscal injuries in children and adolescents is low; however, we see an increase mainly due to intensified sports-related activities at an early age. A meniscal repair should be attempted whenever possible as children present with increased meniscal healing potential. The diagnosis and management of meniscal tears involve both patient factors and tear characteristics: size, anatomical location and associated injuries. Special attention should be given to the feature of ...
Tópico(s): Shoulder Injury and Treatment
2021 - Elsevier BV | Journal of ISAKOS Joint Disorders & Orthopaedic Sports Medicine
Produção Nacional
Revisado por pares
Luciano S. Cruz, Flávio C. Cruz,
We report on continuous-wave second harmonic generation of near infrared Ti:sapphire lasers using room temperature critically phase-matched, angle-tuned BIBO (bismuth triborate, BiB(3)O(6)) crystals, placed both in an external power enhancement cavity and inside the laser resonator. In the first case we generate 70 mW of single-frequency radiation at 423 nm for 330 mW of input power at 846 nm. For intracavity frequency doubling we achieve 690 mW at 423 nm for 7.3 Watts of the Ti:sapphire laser pump ...
Tópico(s): Photorefractive and Nonlinear Optics
2007 - Optica Publishing Group | Optics Express
Flávio Cruz, Ricardo Rocha, Seth Copen Goldstein, Frank Pfenning,
We have designed a new logic programming language called LM (Linear Meld) for programming graph-based algorithms in a declarative fashion. Our language is based on linear logic, an expressive logical system where logical facts can be consumed. Because LM integrates both classical and linear logic, LM tends to be more expressive than other logic programming languages. LM programs are naturally concurrent because facts are partitioned by nodes of a graph data structure. Computation is performed at ...
Tópico(s): Formal Methods in Verification
2014 - Cambridge University Press | Theory and Practice of Logic Programming
Produção Nacional
J.C.S. Moraes, E. M. Telles, Flávio C. Cruz, A. Scalabrin, D. Pereira, C. M. Garelli, N. Ioli, A. Moretti, F. Strumia,
Tópico(s): Spectroscopy and Laser Applications
1991 - Springer Science+Business Media | International Journal of Infrared and Millimeter Waves
Produção Nacional
Revisado por pares
Flávio C. Cruz, A. Scalabrin, D. Pereira, Pedro A. M. Vazquez, Y. Hase, F. Strumia,
The infrared absorption spectra of the gas-phase 13C-methanol isotopomers, 13CH3OH, 13CD3OH, and 13CD3OD, were measured in the wavenumber region between 400 and 4000 cm−1, at instrumental resolutions of 4 and 0.12 cm−1. The fundamental vibrational wavenumbers were assigned from the spectra with the aid of a normal coordinate analysis using the valence force constants recently determined for the gas-phase 12C isotopomers. Using the fundamental wavenumbers of both 12C and 13C-methanol isotopomers, ...
Tópico(s): Atmospheric Ozone and Climate
1992 - Elsevier BV | Journal of Molecular Spectroscopy
Produção Nacional
Wictor C. Magno, Reinaldo L. Cavasso Filho, Flávio C. Cruz,
The possibility of laser cooling of alkaline-earth-metal atoms and ytterbium atoms using a two-photon transition is analyzed. We consider a ${}^{1}{S}_{0}{\ensuremath{-}}^{1}{S}_{0}$ transition with excitation in near resonance with the ${}^{1}{P}_{1}$ level. This greatly increases the two-photon transition rate, allowing an effective transfer of momentum. The experimental implementation of this technique is discussed and we show that for calcium, for example, two-photon cooling can be used to achieve a Doppler ...
Tópico(s): Quantum optics and atomic interactions
2003 - American Physical Society | Physical Review A
Produção Nacional
Revisado por pares
R. L. Cavasso-Filho, A. Mirage, A. Scalabrin, D. Pereira, Flávio C. Cruz,
We investigated the use of hollow-cathode discharges for high-resolution and high-sensitivity spectroscopy, using atomic calcium. Spectra with sub-Doppler resolution of Cai transitions at 423 (resonant), 610, 612, 616, 645, 657 (intercombination), and 672 nm were obtained by optogalvanic saturation spectroscopy in lamps filled with argon (0.6 and 2.5 Torr) and krypton (0.6 Torr). A Doppler background that is due to velocity-changing collisions, which may severely limit the resolution, can be greatly ...
Tópico(s): Cold Atom Physics and Bose-Einstein Condensates
2001 - Optica Publishing Group | Journal of the Optical Society of America B
Produção Nacional
Revisado por pares
Flávio C. Cruz, Daniel L. Maser, Todd A. Johnson, Gabriel Ycas, A. Klose, Fabrizio R. Giorgetta, Ian Coddington, Scott A. Diddams,
Mid-infrared femtosecond optical frequency combs were produced by difference frequency generation of the spectral components of a near-infrared comb in a 3-mm-long MgO:PPLN crystal. We observe strong pump depletion and 9.3 dB parametric gain in the 1.5 μm signal, which yields powers above 500 mW (3 μW/mode) in the idler with spectra covering 2.8 μm to 3.5 μm. Potential for broadband, high-resolution molecular spectroscopy is demonstrated by absorption spectra and interferograms obtained by heterodyning ...
Tópico(s): Laser-Matter Interactions and Applications
2015 - Optica Publishing Group | Optics Express
Produção Nacional
Revisado por pares
Antonio Gil Vicente de Brum, A. Hetem, Israel Rêgo, Cayo Prado Fernandes Francisco, Andre Fenili, Fernando Madeira, Flávio C. Cruz, M.H. Assaf,
The Brazilian deep space mission ASTER, as temporarily named, plans to send a small spacecraft to encounter and investigate the triple asteroid 2001-SN263. The launch is scheduled (initially) to occur in 2015, arriving in 2018. The main motivation of the mission is the development of technology and expertise to leverage the national space sector. Within the scientific goals, the investigation of the still unknown asteroid 2001-SN263. The main project guideline is to aggregate the widest possible ...
Tópico(s): Space Satellite Systems and Control
2011 - Aerospace Technology and Science Department | Journal of Aerospace Technology and Management
Matthew C. Stowe, Flávio C. Cruz, Adela Marian, Jun Ye,
We demonstrate high resolution coherent control of cold atomic Rubidium utilizing spectral phase manipulation of a femtosecond optical frequency comb. Transient coherent accumulation is directly manifested by the enhancement of signal amplitude and spectral resolution via the pulse number. The combination of frequency comb technology and spectral phase manipulation enables coherent control techniques to enter a new regime with natural linewidth resolutions.
Tópico(s): Solid State Laser Technologies
2006 - American Physical Society | Physical Review Letters
Flávio C. Cruz, Matthew C. Stowe, Jun Ye,
A tapered semiconductor amplifier is injection seeded by a femtosecond optical frequency comb at 780 nm from a mode-locked Ti:sapphire laser. Energy gains of more than 17 dB(12 dB) are obtained for 1 mW(20 mW) of average input power when the input pulses are stretched into the picosecond range. A spectral window of supercontinuum light generated in a photonic fiber has also been amplified. Interferometric measurements show sub-Hertz linewidths for a heterodyne beat between the input and amplified ...
Tópico(s): Laser-Matter Interactions and Applications
2006 - Optica Publishing Group | Optics Letters
Produção Nacional
Nicola Malossi, S. Damkjær, Per Lunnemann, L Jacobsen, L. Kindt, Sébastien Sauge, J. W. Thomsen, Flávio C. Cruz, M. Allegrini, E. Arimondo,
A two-photon mechanism for cooling atoms below the Doppler temperature is analyzed. We consider the magnesium ladder system $(3{s}^{2})^{1}S_{0}\ensuremath{\rightarrow}(3s3p)^{1}P_{1}$ at $285.2\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ followed by the $(3s3p)^{1}P_{1}\ensuremath{\rightarrow}(3s3d)^{1}D_{2}$ transition at $880.7\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. For the ladder system quantum coherence effects may become important. Combined with the basic two-level Doppler cooling process this allows ...
Tópico(s): Quantum optics and atomic interactions
2005 - American Physical Society | Physical Review A
Produção Nacional
F. A. Brito, Flávio França Cruz, JOCIKELI FRANCO OLIVEIRA,
We consider our universe as a 3d domain wall embedded in a 5d dimensional Minkowski space-time. We address the problem of inflation and late time acceleration driven by bulk particles colliding with the 3d domain wall. The expansion of our universe is mainly related to these bulk particles. Since our universe tends to be permeated by a large number of isolated structures, as temperature diminishes with the expansion, we model our universe with a 3d domain wall with increasing internal structures. ...
Tópico(s): Galaxies: Formation, Evolution, Phenomena
2005 - American Physical Society | Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology
Andrew H. Steinbach, M. Rauner, Flávio C. Cruz, Jonas Bergquist,
We present a study of the efficiency and optimization of cw second harmonic generation by elliptical Gaussian laser beams. Elliptical focusing slightly improves conversion efficiency and reduces crystal damage risk when heavy walk-off is present. Single-pass measurements of the efficiency for doubling 515-nm radiation in beta-barium borate (BBO) agree with theory. Thermal effects, caused by radiation absorption, limit the doubling efficiency of single-frequency radiation in an external enhancement ...
Tópico(s): Advanced Fiber Laser Technologies
1996 - Elsevier BV | Optics Communications
R. Oltra, Oğuz Yavaṣ, Flávio C. Cruz, J.P. Boquillon, Carlos Humberto Sartori,
Laser cleaning appears to be a suitable replacement for solvent based cleaning techniques in a wide range of technological domains. The short pulsed laser irradiation (few nanoseconds or shorter) in the range of 1–100 MW cm−2 has been tentatively applied in a large range of wavelengths (from UV to IR) for cleaning of various kinds of contaminated surfaces, e.g. metallic surface, ceramic surface, stone, etc. This paper will be focused on the modelling and development of diagnostics of pulsed laser- ...
Tópico(s): Advanced Sensor Technologies Research
1996 - Elsevier BV | Applied Surface Science
Produção Nacional
Revisado por pares
Francisco Senna Vieira, Flávio C. Cruz, David F. Plusquellic, Scott A. Diddams,
Terahertz dual frequency comb spectroscopy (THz-DFCS) yields high spectral resolution without compromising bandwidth. Nonetheless, the resolution of THz-DFCS is usually limited by the laser repetition rate, which is typically between 80 MHz and 1 GHz. In this paper, we demonstrate a new method to achieve sub-repetition rate resolution in THz-DFCS by adaptively modifying the effective laser repetition rate using integrated Mach-Zehnder electro-optic modulators (MZ-EOMs). Our results demonstrate that ...
Tópico(s): Terahertz technology and applications
2016 - Optica Publishing Group | Optics Express
D. J. Berkeland, Flávio C. Cruz, Jonas Bergquist,
Over 2 mW of continuous-wave tunable 194-nm light is produced by sum-frequency mixing approximately 500 mW of 792-nm and 500 mW of 257-nm radiation in beta-barium borate (BBO). The powers in both fundamental beams are enhanced in separate ring cavities whose optical paths overlap in the Brewster-cut BBO crystal. Due to the higher circulating fundamental powers, the sum-frequency-generated power is nearly 2 orders of magnitude greater than previously reported values.
Tópico(s): Advanced Fiber Laser Technologies
1997 - Optica Publishing Group | Applied Optics
B.C. Young, Flávio C. Cruz, Wayne M. Itano, Jonas Bergquist,
We report a visible laser with a subhertz linewidth for use in precision spectroscopy and as a local oscillator for an optical frequency standard. The laser derives its stability from a well-isolated, high-finesse, Fabry-P\'erot cavity. For a 563 nm laser beam locked to our stable cavity, we measure a linewidth of 0.6 Hz for averaging times up to 32 s. The fractional frequency instability for the light locked to the cavity is typically $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$ ...
Tópico(s): Cold Atom Physics and Bose-Einstein Condensates
1999 - American Physical Society | Physical Review Letters
Produção Nacional
Revisado por pares
Daniel L. Maser, Gabriel Ycas, William Iunes Depetri, Flávio C. Cruz, Scott A. Diddams,
Tópico(s): Laser-Matter Interactions and Applications
2017 - Springer Science+Business Media | Applied Physics B
Abijith S. Kowligy, Alex Lind, Daniel D. Hickstein, David R. Carlson, Henry Timmers, Nima Nader, Flávio C. Cruz, Gabriel Ycas, Scott B. Papp, Scott A. Diddams,
We experimentally demonstrate a simple configuration for mid-infrared (MIR) frequency comb generation in quasi-phase-matched lithium niobate waveguides using the cascaded-χ(2) nonlinearity. With nanojoule-scale pulses from an Er:fiber laser, we observe octave-spanning supercontinuum in the near-infrared with dispersive wave generation in the 2.5-3 μm region and intrapulse difference frequency generation in the 4-5 μm region. By engineering the quasi-phase-matched grating profiles, tunable, narrowband ...
Tópico(s): Laser-Matter Interactions and Applications
2018 - Optica Publishing Group | Optics Letters
Produção Nacional
Revisado por pares
Nima Nader, Daniel L. Maser, Flávio C. Cruz, Abijith S. Kowligy, Henry Timmers, Jeff Chiles, Connor Fredrick, Daron Westly, Sae Woo Nam, Richard P. Mirin, Jeffrey M. Shainline, Scott A. Diddams,
Laser frequency combs, with their unique combination of precisely defined spectral lines and broad bandwidth, are a powerful tool for basic and applied spectroscopy. Here, we report offset-free, mid-infrared frequency combs and dual-comb spectroscopy through supercontinuum generation in silicon-on-sapphire waveguides. We leverage robust fabrication and geometrical dispersion engineering of nanophotonic waveguides for multi-band, coherent frequency combs spanning 70 THz in the mid-infrared (2.5 μm– ...
Tópico(s): Photonic Crystal and Fiber Optics
2018 - AIP Publishing | APL Photonics
Henry Timmers, Abijith S. Kowligy, Alex Lind, Flávio C. Cruz, Nima Nader, Myles Silfies, Gabriel Ycas, Thomas K. Allison, Peter G. Schunemann, Scott B. Papp, Scott A. Diddams,
Spectroscopy in the molecular fingerprint spectral region (6.7–20 µm) yields critical information on material structure for physical, chemical, and biological sciences. Despite decades of interest and effort, this portion of the electromagnetic spectrum remains challenging to cover with conventional laser technologies. In this paper, we present a simple and robust method for generating super-octave, optical frequency combs in the fingerprint region through intra-pulse difference frequency generation ...
Tópico(s): Laser-Matter Interactions and Applications
2018 - Optica Publishing Group | Optica
Produção Nacional
Revisado por pares
Abijith S. Kowligy, Henry Timmers, Alexander J. Lind, Ugaitz Elu, Flávio C. Cruz, Peter G. Schunemann, Jens Biegert, Scott A. Diddams,
Probing matter with light in the mid-infrared provides unique insight into molecular composition, structure, and function with high sensitivity. However, laser spectroscopy in this spectral region lacks the broadband or tunable light sources and efficient detectors available in the visible or near-infrared. We overcome these challenges with an approach that unites a compact source of phase-stable, single-cycle, mid-infrared pulses with room temperature electric field-resolved detection at video ...
Tópico(s): Spectroscopy Techniques in Biomedical and Chemical Research
2019 - American Association for the Advancement of Science | Science Advances
Produção Nacional
Revisado por pares
Nima Nader, Abijith S. Kowligy, Jeff Chiles, Eric J. Stanton, Henry Timmers, Alexander J. Lind, Flávio C. Cruz, Daniel Lesko, Kimberly A. Briggman, Sae Woo Nam, Scott A. Diddams, Richard P. Mirin,
Nanophotonic waveguides with sub-wavelength mode confinement and engineered dispersion profiles are an excellent platform for application-tailored nonlinear optical interactions at low pulse energies.Here, we present fully air clad suspended-silicon waveguides for infrared frequency comb generation with optical bandwidth limited only by the silicon transparency.The achieved spectra are lithographically tailored to span 2.1 octaves in the mid-infrared (2.0-8.5 µm or 1170-5000 cm -1 ) when pumped at 3. ...
Tópico(s): Spectroscopy and Laser Applications
2019 - Optica Publishing Group | Optica
Produção Nacional
Revisado por pares
Alexander J. Lind, Abijith S. Kowligy, Henry Timmers, Flávio C. Cruz, Nima Nader, Myles Silfies, Thomas K. Allison, Scott A. Diddams,
Mid-infrared laser frequency combs are compelling sources for precise and sensitive metrology with applications in molecular spectroscopy and spectro-imaging. The infrared atmospheric window between 3-5.5 $\mu$m in particular provides vital information regarding molecular composition. Using a robust, fiber-optic source of few-cycle pulses in the near-infrared, we experimentally demonstrate ultra-broad bandwidth nonlinear phenomena including harmonic and difference frequency generation in a single ...
Tópico(s): Spectroscopy and Laser Applications
2020 - American Physical Society | Physical Review Letters
Produção Nacional
Revisado por pares
Optical frequency combs generated by multiple four-wave mixing of two stabilized single-frequency lasers in optical fibers are proposed for use as high precision frequency markers, calibration of astrophysical spectrometers and metrology. Use of highly nonlinear and photonic crystal fibers with very short lengths and small group velocity dispersion, combined with energy and momentum conservation required by the parametric generation, assures negligible phase mismatch between comb frequencies. In ...
Tópico(s): Laser-Matter Interactions and Applications
2008 - Optica Publishing Group | Optics Express
Flávio E. Cruz, Silvio de Oliveira,
Some specific processes are required to obtain pure hydrogen and the most usual one is natural gas reforming, where natural gas reacts with superheated steam producing H2, CO, CO2 and H2O. This paper presents the exergy and production costs evaluation of a complete hydrogen production unit of a petroleum refinery. The hydrogen production unit analysed in this paper has to supply 550,000 Nm3 of hydrogen per day to purify diesel oil. Based on a synthesis plant of the hydrogen production unit, the ...
Tópico(s): Global Energy and Sustainability Research
2008 - | International Journal of Thermodynamics
Produção Nacional
Orion Augusto Platt Neto, Flávio da Cruz, Sandra Rolim Ensslin, Leonardo Ensslin,
This paper aims to present the compulsory nature and reach of the principles of publicity and transparency in the Brazilian public administration, focusing on the divulgation of the public accounts. In Brazil, the transparency is considered a principle of the responsible fiscal management that comes from the constitutional principle of publicity. Though, the transparency is a wider concept than the publicity, that because information can be public but not be important, reliable, opportune and comprehensible. ...
Tópico(s): E-Government and Public Services
2007 - | Contabilidade Vista & Revista