Equatorial F region vertical plasma drifts, spread F and anomaly responses, in the south American longitude sector during the superstorm of 30 October 2003, are analyzed using data from an array of ...instruments consisting of Digisondes, a VHF radar, GPS TEC and scintillation receivers in Brazil, and a Digisonde and a magnetometer in Jicamarca, Peru. Prompt penetrating eastward electric field of abnormally large intensity drove the F layer plasma up at a velocity ∼1200 ms−1 during post dusk hours in the eastern sector over Brazil. The equatorial anomaly was intensified and expanded poleward while the development of spread F/plasma bubble irregularities and GPS signal scintillations were weaker than their quiet time intensity. Significantly weaker F region response over Jicamarca presented a striking difference in the intensity of prompt penetration electric field between Peru and eastern longitudes of Brazil. The enhanced post dusk sector vertical drift over Brazil is attributed to electro‐dynamics effects arising energetic particle precipitation in the South Atlantic Magnetic Anomaly (SAMA). These extraordinary results and their longitudinal differences are presented and discussed in this paper.
We observed the cluster CIZA J2242.8+5301 with the Arcminute Microkelvin Imager at 16 GHz and present the first high radio-frequency detection of diffuse, non-thermal cluster emission. This cluster ...hosts a variety of bright, extended, steep-spectrum synchrotron-emitting radio sources, associated with the intracluster medium, called radio relics. Most notably, the northern, Mpc-wide, narrow relic provides strong evidence for diffusive shock acceleration in clusters. We detect a puzzling, flat-spectrum, diffuse extension of the southern relic, which is not visible in the lower radio-frequency maps. The northern radio relic is unequivocally detected and measures an integrated flux of 1.2 ± 0.3 mJy. While the low-frequency (<2 GHz) spectrum of the northern relic is well represented by a power law, it clearly steepens towards 16 GHz. This result is inconsistent with diffusive shock acceleration predictions of ageing plasma behind a uniform shock front. The steepening could be caused by an inhomogeneous medium with temperature/density gradients or by lower acceleration efficiencies of high energy electrons. Further modelling is necessary to explain the observed spectrum.
We describe the far-infrared (far-IR; rest-frame 8-1000-μm) properties of a sample of 443 Hα-selected star-forming galaxies in the Cosmic Evolution Survey (COSMOS) and Ultra Deep Survey (UDS) fields ...detected by the High-redshift Emission Line Survey (HiZELS) imaging survey. Sources are identified using narrow-band filters in combination with broad-band photometry to uniformly select Hα (and O ii if available) emitters in a narrow redshift slice at z = 1.47 ± 0.02. We use a stacking approach in Spitzer-MIPS mid-IR, Herschel-PACS/SPIRE far-IR from the PACS Evolutionary Prove (PEP) and Herschel Multi-tiered Extragalactic Survey (HerMES) and AzTEC mm-wave images to describe their typical far-IR properties. We find that HiZELS galaxies with observed Hα luminosities of L(Hα)obs 108.1-9.1 L ( 1041.7-42.7 erg s−1) have bolometric far-IR luminosities of typical luminous IR galaxies,
L. Combining the Hα and far-IR luminosities, we derive median star formation rates (SFRs) of SFRHα, FIR = 32 ± 5 M yr−1 and Hα extinctions of A
Hα = 1.0 ± 0.2 mag. Perhaps surprisingly, little difference is seen in typical HiZELS extinction levels compared to local star-forming galaxies. We confirm previous empirical stellar mass (M
*) to A
Hα relations and the little or no evolution up to z = 1.47. For HiZELS galaxies (or similar samples) we provide an empirical parametrization of the SFR as a function of rest-frame (u − z) colours and 3.6-μm photometry - a useful proxy to aid in the absence of far-IR detections in high-z galaxies. We find that the observed Hα luminosity is a dominant SFR tracer when rest-frame (u − z) colours are 0.9 mag or when Spitzer-3.6-μm photometry is fainter than 22 mag (Vega) or when stellar masses are lower than 109.7 M. We do not find any correlation between the O ii/Hα and far-IR luminosity, suggesting that this emission line ratio does not trace the extinction of the most obscured star-forming regions, especially in massive galaxies where these dominate. The luminosity-limited HiZELS sample tends to lie above of the so-called main sequence for star-forming galaxies, especially at low stellar masses, indicating high star formation efficiencies in these galaxies. This work has implications for SFR indicators and suggests that obscured star formation is linked to the assembly of stellar mass, with deeper potential wells in massive galaxies providing dense, heavily obscured environments in which stars can form rapidly.
We analyze in detail the zonal velocities of large‐scale ionospheric plasma depletions over two conjugate stations inferred from OI 630 nm airglow all‐sky images obtained during the Conjugate Point ...Equatorial Experiment (COPEX) campaign carried out in Brazil between October and November 2002. The conjugate stations were Boa Vista (BV) (geogr. 2.8N, 60.7W, dip angle 22.0°N) and Campo Grande (CG) (geogr. 20.5S, 54.7W, dip angle 22.32°S). Over Campo Grande, the zonal velocities were measured also by a system of spaced GPS scintillation receivers. The airglow zonal velocities at the conjugate sites were seen to agree very closely, except for a slightly increased velocity over CG which we attribute to the presence of the geomagnetic anomaly. The results show a high degree of alignment of the bubbles along the geomagnetic field lines during the bubble development phase and as the bubbles travel eastward, thereby suggesting that the neutral zonal wind effect in the zonal plasma motion is an integrated effect along the flux tube. The zonal velocities obtained from the GPS technique were always larger than those calculated by the airglow technique, which permitted observation of zonal plasma velocity shear between the altitudes of the airglow emitting layer and of the GPS scintillation. Theoretical ambient plasma zonal velocities calculated using the formulations by Haerendel et al. (1992) and Eccles (1998) are compared with the experimental results. Our results also reveal some degree of dependence of the zonal velocities on the solar flux (F10.7) and magnetic (Kp) indices during the COPEX period.
The objective of this paper was to study the effect of plasticizers and their concentrations on the thermal and functional properties of gelatin-based films. Four polyols (glycerol—GLY, propylene ...glycol—PPG, di- DTG and ethylene glycol—ETG) were tested in five concentrations: 10, 15, 20, 25, and 30
g plasticizer/100
g of gelatin. For thermal analysis, the films were conditioned in desiccators with silica gel and for functional properties (mechanical properties, water vapor permeability, color and opacity) characterizations, the films were conditioned at 25
°C and 58% relative humidity. The results were discussed in terms of ‘plasticizer efficiency’ meaning plasticizer content effect and also in terms of ‘plasticizer effect’ meaning the plasticizer type effect on the properties. In a general manner, the higher plasticizing effect on thermal properties was observed with the DTG, followed by PPG, GLY and ETG, principally with low plasticizer content. However, also in terms of thermal properties, the ETG presented the higher plasticizer efficiency followed by the GLY, DTG and PPG. Concerning the mechanical properties, the GLY showed the greater plasticizing effect and efficiency, but the plasticizing efficiency of DTG on the puncture deformation was also considerable. The mechanical resistance could be related with the glass transition temperature of films. It was not possible to observe the plasticizer effect on the water vapor permeability (WVP), but the DTG had shown greater plasticizer efficiency, followed by GLY and ETG, while a counter effect was observed with PPG. The effect of the type and concentration of plasticizer on the color and opacity of films could be considered as negligible. In conclusion, the more important plasticizer effect and efficiency were observed with DTG and ETG on the thermal properties, and with the GLY in terms of functional properties. The behavior of the mechanical properties of films could be explained by its glass transition temperature.
The optimal formulation for the preparation of amaranth flour films plasticized with glycerol and sorbitol was obtained by a multi-response analysis. The optimization aimed to achieve films with ...higher resistance to break, moderate elongation and lower solubility in water. The influence of plasticizer concentration (Cg, glycerol or Cs, sorbitol) and process temperature (Tp) on the mechanical properties and solubility of the amaranth flour films was initially studied by response surface methodology (RSM). The optimized conditions obtained were Cg 20.02 g glycerol/100 g flour and Tp 75 °C, and Cs 29.6 g sorbitol/100 g flour and Tp 75 °C. Characterization of the films prepared with these formulations revealed that the optimization methodology employed in this work was satisfactory. Sorbitol was the most suitable plasticizer. It furnished amaranth flour films that were more resistant to break and less permeable to oxygen, due to its greater miscibility with the biopolymers present in the flour and its lower affinity for water.
► Mechanical properties and solubility in water of amaranth flour film were optimized. ► The optimization methodology employed in this work was satisfactory. ► Sorbitol was the most suitable plasticizer for flour films compared to the glycerol. ► Formation of a more homogeneous and ordered structure in the presence of sorbitol.
Edible films are thin materials based on a biopolymer. The objectives of this work were to determine the water vapor permeability and the mechanical and thermal properties of edible films based on ...bovine hide and pigskin gelatins. These films were prepared with 1
g of gelatin/100
ml of water; 15–65
g sorbitol/100
g gelatin; and at natural pH. The samples were conditioned at 58% relative humidity and 22°C for 4 days before testing. The mechanical properties were determined by the puncture test and the water vapor permeability by gravimetric method at 22°C. For DSC analysis, samples were conditioned over silica gel for 3 weeks. Samples (∽10
mg) were heated at 5°C/min, between −150 and 150°C in a DSC TA 2010. A second scan was run after cell cooling with liquid nitrogen. As expected, the puncture force decreased and the puncture deformation and water vapor permeability increased with the sorbitol content. The origin of gelatin was important only above 25
g sorbitol/100
g gelatin. The DSC traces obtained in the first scan of samples with 15–35
g sorbitol/100
g gelatin, showed a well visible glass transition followed by a sol–gel transition. However, with the increase of sorbitol concentration, the glass transition became broader, typical of the system presenting a phase separation. The model of Couchman and Karazs for ternary system, was used to predict the Tg values as a function of sorbitol concentration.
Equatorial plasma bubbles consist of field‐aligned large‐scale depletions, or irregularities, characterized by drastic ion density rarefactions of the nocturnal low latitude/equatorial ionosphere. ...Understanding their behavior is important because of their degrading effects on radio wave signals and, consequently, their respective technological applications such as, for example, Global Positioning System applications. In this sense, a methodology of pattern recognition was developed and implemented here using the Long‐Term Ionospheric Anomaly Monitoring in order to infer the plasma bubbles zonal drift velocities, using two receiving stations of global navigation satellite systems data from the Brazilian Continuous Monitoring Network, located near to each other, in Salvador (BA) during geomagnetically quiet periods. The study covered the years of 2012, 2013, and 2014 for the months from September to January of the following year, choosing 10 representative days for each month. The average results for the plasma bubble zonal velocities provided by the model calculations were in agreement with the well‐known values. However, monthly individual analysis showed a behavior anticorrelated with that expected for high solar flux. Probably, the unexpected behavior is due to atypical configuration of the solar activity ascending phase.
Key Points
Automatic calculation of the plasma bubbles velocities by LTIAM model
Using GNSS signals to infer plasma bubbles velocities
The gelatin prepared from the skins of the Atlantic halibut (
Hippoglossus hippoglossus) was investigated for the development of edible films plasticized with 30
g sorbitol/100
g gelatin. Two types ...of dry gelatin preparations were obtained depending on whether an intermediate evaporation step at 60
°C in the drying procedure is included or not. The amino acid composition, molecular weight distribution (determined by SDS-polyacrylamide gel electrophoresis) and glass transition temperature (determined by differential scanning calorimetry) of the gelatins were determined and related to some physical properties of the resulting films. The gelatin extracted from the halibut skins showed a suitable filmogenic capacity, leading to transparent, weakly colored, water-soluble and highly extensible films. The intermediate evaporation step at 60
°C induced thermal protein degradation, causing the resulting films to be significantly less resistant and more extensible. No differences in water vapor permeability, viscoelasticity, glass transition or color properties were evidenced between the two gelatins tested.
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