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

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

Potential of mangrove-associated endophytic fungi for production of carbohydrolases with high saccharification efficiency.

The endophytic fungi represent a potential source of microorganisms for enzyme production. However, there have been only few studies exploiting their potential for the production of enzymes of industrial interest, such as the (hemi)cellulolytic enzymatic cocktail required in the hydrolysis of lignocellulosic biomass. Here, a collection of endophytic fungi isolated from mangrove tropical forests was evaluated for the production of carbohydrolases and performance on the hydrolysis of cellulose. For that, 41 endophytic strains were initially screened using a plate assay containing crystalline cellulose as the sole carbon source and the selected strains were cultivated under solid-state fermentation for endoglucanase, β-glucosidase, and xylanase enzyme quantification. The hydrolysis of a cellulosic material with the enzymes from endophytic strains of the Aspergillus genus resulted in glucose and conversion values more than twofold higher than the reference strains (Aspergillus niger F12 and Trichoderma reesei Rut-C30). Particularly, the enzymes from strains A. niger 56 (3) and A. awamori 82 (4) showed a distinguished saccharification performance, reaching cellulose conversion values of about 35% after 24 h. Linking hydrolysis performance to the screening steps played an important role towards finding potential fungal strains for producing enzymatic cocktails with high saccharification efficiency. These results indicate the potential of mangroveassociated endophytic fungi for production of carbohydrolases with efficient performance in the hydrolysis of biomass, thus contributing to the implementation of future biorefineries

Isolation of micropropagated strawberry endophytic bacteria and assessment of their potential for plant growth promotion.

Twenty endophytic bacteria were isolated from the meristematic tissues of three varieties of strawberry cultivated in vitro, and further identified, by FAME profile, into the genera Bacillus and Sphingopyxis. The strains were also characterized according to indole acetic acid production, phosphate solubilization and potential for plant growth promotion. Results showed that 15 strains produced high levels of IAA and all 20 showed potential for solubilizing inorganic phosphate. Plant growth promotion evaluated under greenhouse conditions revealed the ability of the strains to enhance the root number, length and dry weight and also the leaf number, petiole length and dry weight of the aerial portion. Seven Bacillus spp. strains promoted root development and one strain of Sphingopyxis sp. promoted the development of plant shoots. The plant growth promotion showed to be correlated to IAA production and phosphate solubilization. The data also suggested that bacterial effects could potentially be harnessed to promote plant growth during seedling acclimatization in strawberr

Study of the a_0(980) meson via the radiative decay phi->eta pi^0 gamma with the KLOE detector

We have studied the phi->a_0(980) gamma process with the KLOE detector at the Frascati phi-factory DAPhNE by detecting the phi->eta pi^0 gamma decays in the final states with eta->gamma gamma and eta->pi^+ pi^- pi^0. We have measured the branching ratios for both final states: Br(phi->eta pi^0 gamma)=(7.01 +/- 0.10 +/- 0.20)x10^-5 and (7.12 +/- 0.13 +/- 0.22)x10^-5 respectively. We have also extracted the a_0(980) mass and its couplings to eta pi^0, K^+ K^-, and to the phi meson from the fit of the eta pi^0 invariant mass distributions using different phenomenological models.Comment: 17 pages, 6 figures, submitted to Physics Letters B. Corrected typos in eq.

Affinity proteomic dissection of the human nuclear cap-binding complex interactome

A 5',7-methylguanosine cap is a quintessential feature of RNA polymerase II-transcribed RNAs, and a textbook aspect of co-transcriptional RNA processing. The cap is bound by the cap-binding complex (CBC), canonically consisting of nuclear cap-binding proteins 1 and 2 (NCBP1/2). Interest in the CBC has recently renewed due to its participation in RNA-fate decisions via interactions with RNA productive factors as well as with adapters of the degradative RNA exosome. A novel cap-binding protein, NCBP3, was recently proposed to form an alternative CBC together with NCBP1, and to interact with the canonical CBC along with the protein SRRT. The theme of post-transcriptional RNA fate, and how it relates to co-transcriptional ribonucleoprotein assembly, is abundant with complicated, ambiguous, and likely incomplete models. In an effort to clarify the compositions of NCBP1-, 2- and 3-related macromolecular assemblies, we have applied an affinity capture-based interactome screen where the experimental design and data processing have been modified to quantitatively identify interactome differences between targets under a range of experimental conditions. This study generated a comprehensive view of NCBP-protein interactions in the ribonucleoprotein context and demonstrates the potential of our approach to benefit the interpretation of complex biological pathways