Search results for "shell"
showing 10 items of 748 documents
Molecular insights into shellac film coats from different aqueous shellac salt solutions and effect on disintegration of enteric-coated soft gelatin …
2014
The purpose of this investigation was to study the effect of using different salts of shellac on the disintegration properties of shellac-based enteric coatings. In the last two decades, shellac has been increasingly used as an aqueous solution for enteric coating purposes, with the ammonium salt being the form typically used. Little investigation has been performed on using other salts, and therefore, this was the focus of our work. Enteric coatings, based on different shellac salts (ammonium, sodium, potassium and composite ammonium-sodium), were applied onto soft gelatin capsules. Disintegration testing of the coated soft gelatin capsules showed that alkali metal salts promote faster dis…
The gallium anomaly revisited
2019
The gallium anomaly, i.e. the missing electron-neutrino flux from $^{37}$Ar and $^{51}$Cr electron-capture decays as measured by the GALLEX and SAGE solar-neutrino detectors, has been among us already for about two decades. We present here a new estimate of the significance of this anomaly based on cross-section calculations using nuclear shell-model wave functions obtained by exploiting recently developed two-nucleon interactions. The gallium anomaly of the GALLEX and SAGE experiments is found to be smaller than that obtained in previous evaluations, decreasing the significance from 3.0σ to 2.3σ. This result is compatible with the recent indication in favor of short-baseline ν¯e disappeara…
Quantum-state-selective decay spectroscopy of 213Ra
2017
An experimental scheme combining the mass resolving power of a Penning trap with contemporary decay spectroscopy has been established at GSI Darmstadt. The Universal Linear Accelerator (UNILAC) at GSI Darmstadt provided a 48Ca beam impinging on a thin 170Er target foil. Subsequent to velocity filtering of reaction products in the Separator for Heavy Ion reaction Products (SHIP), the nuclear ground state of the 5n evaporation channel 213Ra was mass-selected in SHIPTRAP, and the 213Ra ions were finally transferred into an array of silicon strip detectors surrounded by large composite germanium detectors. Based on comprehensive geant4 simulations and supported by theoretical calculations, the …
Searching for differences in Swift's intermediate GRBs
2010
Gamma-ray bursts are usually classified through their high-energy emission into short-duration and long-duration bursts, which presumably reflect two different types of progenitors. However, it has been shown on statistical grounds that a third, intermediate population is needed in this classification scheme, although an extensive study of the properties of this class has so far not been done. The large amount of follow-up studies generated during the Swift era allows us to have a suficient sample to attempt a study of this third population through the properties of their prompt emission and their afterglows. Our study is focused on a sample of GRBs observed by Swift during its first four y…
Optical illusions in scanning electron micrographs: the case of the eggshell of Acrosternum (Chinavia) marginatum (Hemiptera: Pentatomidae)
2003
Scanning electron microscopy revealed that-as is common in this family of the Hemiptera-the eggs of the green stink bug Acrosternum (Chinavia) marginatum are roughly barrel-shaped and possess at their apical pole a row of slender extensions, the aero-micropylar processes. The outer surface of the eggshell carries hexagonally arranged pits. The analysis of cross-fractured eggshells showed that the pits have slender basal extensions with transverse diaphragms. When scanning electron micrographs of the egg surface of A. marginatum are viewed upside down, the perception flips and the pits appear as elevations to all observers addressed. Thus, we are dealing with an optical illusion, which is kn…
En-Face differential absorption optical coherence tomography with gold nanorods as the contrast agent
2008
A new variety of nanoparticles showing unique and characteristic optical properties, appeals for its use as contrast agents in medical imaging. Gold nanospheres, nanorods and nanoshells with a silica core are new forms of promising contrast agents which can be tuned to specific absorption or scattering characteristics within the near-infrared (NIR) spectrum ranging from 650 - 1300 nm. They have the ability to be used for both image enhancement and as photosensitive markers due to their well designable scattering and absorption properties. Furthermore, their strong optical absorption permits treatment of malignant cells by photoablation processes, induced when heating them with a matched lig…
Electron Spin Resonance and Thermoluminescence dating of shells and sediments from Sambaqui (shell mound) Santa Marta II, Brazil
2020
In Tupi, the word Sambaqui means “mound of shells”. These archaeological sites are cultural vestiges left by the prehistoric occupation of the Brazilian coast from five to six thousand years ago. Mollusks, fishes, and other marine edible foods were important for the survival of this population. The remains of foods, mainly shells, were heaped up, giving a mound of different proportions, which became part of the landscape of the Brazilian coastal plain. Due to the large number of Sambaquis in Brazil and considering that Sambaqui Santa Marta II, Laguna, SC, has not yet been dated, Electron Spin Resonance (ESR) measurements were performed in aragonite shells collected from different layers of …
Artificial Reefs in Sicily: An Overview
2000
Sicilian cave drawings from the Grotta del Genovese, Isle of Levanzo (west Sicily) ca. 12 000 B.C. show silhouettes of dolphins, tuna, groupers and bass which, together with remains offish (tuna, groupers, bass and others), limpets and oysters from Grotta dell Uzzo, north-western Sicily, indicate the importance of fish and shellfish in the diet of coastal populations of that time (Villari, 1992a, 1992b). Remains of turtles (Caretta caretta), tuna and sharks are evidence of fishing activity during this period (Villari, 1995).
EPR dating of shells from Malhada Marsh, Rio de Janeiro, Brazil
2020
The formation of the coastal plain of the Brazilian sea is mainly due to the fluctuation of relative sea level in the past. Armacao dos Buzios or simply Buzios is a municipality in the microregion of lakes, in the state of Rio de Janeiro. In this region there is a lowland area about two meters above current sea level. This lowland area is also known as coastal plain of Una River. It is expected that during the Holocene period the sea level reached a maximum about 2.5 meters above the current level. During that time billions of mollusks lived and proliferated in the shallow waters around the coastal plain of the Una River. As they died their shells formed a layer in the soil including Malhad…
Lowstand carbonates, highstand sandstones?
2003
The sedimentary facies, sediment dynamics and sequence architecture of modern high-energy shelves in the mid and high latitudes are largely governed by wave abrasion processes. Cool-water carbonates may form there, if the influx and/or net accretion of siliciclastics is kept at a minimum. Little dilution of the carbonate produced in situ is generally promoted by a wide "epicontinental" shelf, subdued topography of the adjacent mainland, the predominance of limestone outcrops, and an arid climate. The aforementioned requirements are rarely met, and thus will automatically lead to the formation of mixed siliciclastic-cool-water carbonates. Such an example is found in the Early to Mid-Miocene …