Biotechnological potential of endophytic and rhizospheric bacteria for plant growth promotion in Paspalum species.

Paspalum is a large grass genus of the Poaceae family, comprising several important forage species which occur in the Tropics and warm temperate regions, mainly in the American continent, especially abundant in Brazil.June 10-13, 2019

MEASUREMENT OF THE REGRESSION RATE IN A HYBRID ROCKET MOTOR BY ACQUIRING THE HELMHOLTZ FREQUENCY IN THE COMBUSTION CHAMBER

Low thrust values obtained with a hybrid rocket motor (HRM) are a consequence of the difficulty in quickly mixing the fuel and oxidizer, which is characterized by a low regression rate of the fuel grain. Therefore, the measurement of this parameter is of great importance in studies that aim at solutions for this deficiency in HRM. Several studies calculate a reliable value of the average regression rate over time by measuring the total mass of fuel before and after each burn. A method to measure instantaneous regression rate is by acquiring the Helmholtz resonance frequency in the combustion chamber. This work uses a piezoelectric pressure transducer to obtain the Helmholtz frequency mode of the combustion chamber in a laboratory scale test bench with high-density polyethylene (HDPE) and gaseous oxygen, and is based on the principle that this frequency is inversely proportional to the square-root of the chamber volume. With the chamber volume variation, the port diameter of the grain variation is obtained. In conclusion, the calculated variation of port diameter agreed well with the correlation for average regression rate, determined from mass loss during operation

Ensemble of Hankel Matrices for Face Emotion Recognition

In this paper, a face emotion is considered as the result of the composition of multiple concurrent signals, each corresponding to the movements of a specific facial muscle. These concurrent signals are represented by means of a set of multi-scale appearance features that might be correlated with one or more concurrent signals. The extraction of these appearance features from a sequence of face images yields to a set of time series. This paper proposes to use the dynamics regulating each appearance feature time series to recognize among different face emotions. To this purpose, an ensemble of Hankel matrices corresponding to the extracted time series is used for emotion classification within a framework that combines nearest neighbor and a majority vote schema. Experimental results on a public available dataset shows that the adopted representation is promising and yields state-of-the-art accuracy in emotion classification.Comment: Paper to appear in Proc. of ICIAP 2015. arXiv admin note: text overlap with arXiv:1506.0500

Nonlinear properties of AlGaAs waveguides in continuous wave operation regime

Aluminum Gallium Arsenide (AlGaAs) is an attractive platform for the development of integrated optical circuits for all-optical signal processing thanks to its large nonlinear coefficients in the 1.55-μm telecommunication spectral region. In this paper we discuss the results of the nonlinear continuous-wave optical characterization of AlGaAs waveguides at a wavelength of 1.55 μm. We also report the highest value ever reported in the literature for the real part of the nonlinear coefficient in this material (Re(γ) ≈521 W<sup>−1</sup>m<sup>−1</sup>)

ACOUSTIC CAVITIES DESIGN PROCEDURES

Combustion instability is recognized as one of the major problems frequently faced by engineers during the development of either liquid or solid propellant rocket engines. The performance of the engine can be highly affected by these high frequencies instabilities, possibly leading the rocket to an explosion. The main goal while studying combustion chambers instability, either by means of baffles or acoustic absorbers, is to achieve the stability needed using the simplest possible manner. This paper has the purpose of studying combustion chambers instabilities, as well as the design of acoustic absorbers capable of reducing their eigenfrequencies. Damping systems act on the chamber eigenfrequency, which has to be, therefore, previously known

EXPERIMENTAL STUDY WITH DIFFERENT STRATEGIES AND AIR-DILUTION USING OPTICAL SI ENGINE FUELED WITH HYDRATED ETHANOL

Several dilution conditions techniques are used in internal combustion engines to increase fuel economy and reduce pollutant emissions, primarily nitrogen oxide (NOX), which are generated by the thermal pathway. Among the techniques, we can highlight air dilution (lean combustion) and exhaust gas recirculation (EGR). The control of these operations using different types of fuels and biofuels and their peculiarities, are of fundamental importance to remove the maximum efficiency from the process, generating the lowest level of emission and respecting the current legislation. Although several studies have achieved interesting results for reducing emissions and knocks thanks to the dilution of the air, it has been observed that the diluent without oxygen is more efficient. Although air dilution has a slightly lesser effect than EGR, this mode of operation can help to understand the dynamics of engine load dilution, mainly due to the complexity of EGR tests on research engines. Therefore, as a background, tests were carried out experimentally with air dilution in order to understand the behavior for the prediction of future tests with EGR. The tests were performed with hydrated ethanol and speeds of 1500 rpm and 2500 rpm. It was possible to observe that with increasing dilution, there is a gradual increase in the variability of the burn and its displacement to the region close to the inlet valve. It was observed that the dilution provided a decrease in the formation of NOX and CO and an increase in hydrocarbon emissions. Increased rotation due to increased turbulence causes changes in emission values

Silicon photonic Mach Zehnder modulators for next-generation short-reach optical communication networks

Communication traffic grows relentlessly in today’s networks, and with ever more machines connected to the network, this trend is set to continue for the foreseeable future. It is widely accepted that increasingly faster communications are required at the point of the end users, and consequently optical transmission plays a progressively greater role even in short- and medium-reach networks. Silicon photonic technologies are becoming increasingly attractive for such networks, due to their potential for low cost, energetically efficient, high-speed optical components. A representative example is the silicon-based optical modulator, which has been actively studied. Researchers have demonstrated silicon modulators in different types of structures, such as ring resonators or slow light based devices. These approaches have shown remarkably good performance in terms of modulation efficiency, however their operation could be severely affected by temperature drifts or fabrication errors. Mach-Zehnder modulators (MZM), on the other hand, show good performance and resilience to different environmental conditions. In this paper we present a CMOS-compatible compact silicon MZM. We study the application of the modulator to short-reach interconnects by realizing data modulation using some relevant advanced modulation formats, such as 4-level Pulse Amplitude Modulation (PAM-4) and Discrete Multi-Tone (DMT) modulation and compare the performance of the different systems in transmission

Iatrogenic Delirium in an Elderly Patient: When Drugs are Harmful

Delirium is a global disorder of cognition that represents a medical emergency and, particularly in elderly, is often unrecognized or misdiagnosed and commonly mistaken for dementia, depression, mania, or an acute schizophrenic reaction. Drug-induced delirium is a common matter in the elderly and in this paper we report the onset of delirium induced by -drug interaction in a previously health elderly patient