44 research outputs found
Properties of LiMnBO3 glasses and nanostructured glass-ceramics
Polycrystalline LiMnBO3 is a promising cathode material for Li-ion batteries.
In this work, we investigated the thermal, structural and electrical properties
of glassy and nanocrystallized materials having the same chemical composition.
The original glass was obtained via a standard meltquenching method. SEM and
7Li solid-state NMR indicate that it contains a mixture of two distinct glassy
phases. The results suggest that the electrical conductivity of the glass is
dominated by the ionic one. The dc conductivity of initial glass was estimated
to be in the order of 10-18 S.cm-1 at room temperature. The thermal
nanocrystallization of the glass produces a nanostructured glass-ceramics
containing MnBO3 and LiMnBO3 phases. The electric conductivity of this
glass-ceramics is increased by 6 orders of magnitude, compared to the starting
material at room temperature. Compared to other manganese and borate containing
glasses reported in the literature, the conductivity of the nanostructured
glass ceramics is higher than that of the previously reported glassy materials.
Such improved conductivity stems from the facilitated electronic transport
along the grain boundaries
Neurocranial osteology and neuroanatomy of a late Cretaceous Titanosaurian Sauropod from Spain (Ampelosaurus sp.)
Titanosaurians were a flourishing group of sauropod dinosaurs during Cretaceous times. Fossils of titanosaurians have been found on all continents and their remains are abundant in a number of Late Cretaceous sites. Nonetheless, the cranial anatomy of titanosaurians is still very poorly known. The Spanish latest Cretaceous locality of "Lo Hueco" yielded a relatively well preserved, titanosaurian braincase, which shares a number of phylogenetically restricted characters with Ampelosaurus atacis from France such as a flat occipital region. However, it appears to differ from A. atacis in some traits such as the greater degree of dorsoventral compression and the presence of proatlas facets. The specimen is, therefore, provisionally identified as Ampelosaurus sp. It was CT scanned, and 3D renderings of the cranial endocast and inner-ear system were generated. Our investigation highlights that, although titanosaurs were derived sauropods with a successful evolutionary history, they present a remarkably modest level of paleoneurological organization. Compared with the condition in the basal titanosauriform Giraffatitan brancai, the labyrinth of Ampelosaurus sp. shows a reduced morphology. The latter feature is possibly related to a restricted range of head-turning movementsThis is a contribution to the research project CGL2009-12143 (Ministerio de Economía y Competitividad, Madrid), of which FK, who is currently supported by the Ramón y Cajal Program, is Principal Investigator. LMW and RCR acknowledge funding support from the United States National Science Foundation (IBN-9601174, IBN-0343744, IOB-0517257, IOS-1050154) and the Ohio University Heritage College of Osteopathic Medicine. The Ohio Supercomputing Center also provided suppor
An experimental approach for the determination of axial and flexural wavenumbers in circular exponentially tapered bars
A basal lithostrotian titanosaur (Dinosauria: Sauropoda) with a complete skull: Implications for the evolution and paleobiology of titanosauria
We describe Sarmientosaurus musacchioi gen. et sp. nov., a titanosaurian sauropod dinosaur from the Upper Cretaceous (Cenomanian - Turonian) Lower Member of the Bajo Barreal Formation of southern Chubut Province in central Patagonia, Argentina. The holotypic and only known specimen consists of an articulated, virtually complete skull and part of the cranial and middle cervical series. Sarmientosaurus exhibits the following distinctive features that we interpret as autapomorphies: (1) maximum diameter of orbit nearly 40% rostrocaudal length of cranium; (2) complex maxilla - lacrimal articulation, in which the lacrimal clasps the ascending ramus of the maxilla; (3) medial edge of caudal sector of maxillary ascending ramus bordering bony nasal aperture with low but distinct ridge; (4) ´tongue-like´ ventral process of quadratojugal that overlaps quadrate caudally; (5) separate foramina for all three branches of the trigeminal nerve; (6) absence of median venous canal connecting infundibular region to ventral part of brainstem; (7) subvertical premaxillary, procumbent maxillary, and recumbent dentary teeth; (8) cervical vertebrae with ´strut-like´ centroprezygapophyseal laminae; (9) extremely elongate and slender ossified tendon positioned ventrolateral to cervical vertebrae and ribs. The cranial endocast of Sarmientosaurus preserves some of the most complete information obtained to date regarding the brain and sensory systems of sauropods. Phylogenetic analysis recovers the new taxon as a basal member of Lithostrotia, as the most plesiomorphic titanosaurian to be preserved with a complete skull. Sarmientosaurus provides a wealth of new cranial evidence that reaffirms the close relationship of titanosaurs to Brachiosauridae. Moreover, the presence of the relatively derived lithostrotian Tapuiasaurus in Aptian deposits indicates that the new Patagonian genus represents a ´ghost lineage´ with a comparatively plesiomorphic craniodental form, the evolutionary history of which is missing for at least 13 million years of the Cretaceous. The skull anatomy of Sarmientosaurus suggests that multiple titanosaurian species with dissimilar cranial structures coexisted in the early Late Cretaceous of southern South America. Furthermore, the new taxon possesses a number of distinctive morphologies - such as the ossified cervical tendon, extremely pneumatized cervical vertebrae, and a habitually downward- facing snout - that have rarely, if ever, been documented in other titanosaurs, thus broadening our understanding of the anatomical diversity of this remarkable sauropod clade. The latter two features were convergently acquired by at least one penecontemporaneous diplodocoid, and may represent mutual specializations for consuming low-growing vegetation.Fil: Martínez, Rubén Darío. Universidad Nacional de la Patagonia; ArgentinaFil: Lamanna, Matthew C.. Carnegie Museum Of Natural History; Estados UnidosFil: Novas, Fernando Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "bernardino Rivadavia"; ArgentinaFil: Ridgely, Ryan C.. Ohio University College Of Osteopathic Medicine; Estados UnidosFil: Casal, Gabriel. Universidad Nacional de la Patagonia; ArgentinaFil: Martínez, Javier E.. Hospital Regional de Comodoro Rivadavia; ArgentinaFil: Vita, Javier R.. Resonancia Magnética Borelli; ArgentinaFil: Witmer, Lawrence M.. Ohio University College Of Osteopathic Medicine; Estados Unido
Burning of wood slash as a source of air pollution
Concentrations of gaseous air pollutants were measured during burning of wood slash in a clear−cut pine forest stand. Large amounts of CO2 and CO were produced in this process, and the forest ecosystem lost considerable amounts of nitrogen and sulphur. In the study area, increased concentrations of NO, NO2, CO and SO2 were detected in the air. Instantaneous concentrations of NO2 and SO2 sometimes exceeded permissible levels
Soil temperature during wood slash burning
The work presents results of soil temperature measurements under bonfires in which felling residues (branches, twigs, needles) were burnt in a clear−cut area. An increase in soil temperature was observed to the depth of 50 cm below ground level. In the humus horizon, the temperature greatly exceeded the threshold value above which protein denaturation takes place. The ectohumus horizon, with a high water content, initially protected the mineral soil against an increase in temperature and later retarded this increase
Health status of European ash (Fraxinus excelsior L.) in relation to the moisture of selected forest sites
The study aimed to determine the influence of site moisture conditions on the health status of European ash. The research plots were located in the Babki, Konstantynowo and Łopuchówko forest districts, as well as in the Poznań Municipal Forests (western Poland). The research was
carried out on 30 research plots established in the part of the stands with at least 80% share of ash in the stand species composition. Ash aged from 48 to 144 years. The scope of the research included: (1) selection of the research plots and determination of the forest site type, (2) assessment of site moisture conditions – the type and degree of moisture and the depth of the groundwater level, (3) selection of 15 trees belonging to the 1st and 2nd Kraft’s class and assessment of their health status using the synthetic damage indicator, which is based on the crown defoliation and vitality of upper part of the crown. Results revealed that the best health status of ash stands was noted in mesic broadleaved forest. In contrast, within the stands in moist broadleaved forest, alder−ash forest and riparian forest we observed the highest share of damaged and dying trees. The more detailed analysis of moisture conditions showed that the lowest damage of ash was noted within the stands with the groundwater level at depth below 1.8 m and up to 0.5 m. Moreover, a high share of healthy and weakened trees occurred also within the stands with water flowing down the slope and in the compact soils, where water does not undergo significant level
fluctuations. The most damaged stands occurred mostly in dehydrated soils, as well as in the soils where the depth of the groundwater was between 0.5 and 1.8 m
Heart motion visualization tools for 4D echocadiographic images
Qualitative and quantitative description of the heart wall motion is a very important field of investigation in modern cardiology. Abnormalities in heart motion are usually symptoms of life threatening cardiac dysfunctions therefore measurements of dynamic heart functions are of great clinical importance. The images of moving spatial heart structures can be efficiently acquired using 4D echocardiography. Unfortunately because of the low quality such images do not allow for precise measurements. To overcome this problem images need to be further processed and moving structures have to be extracted. In this work we present a method for estimating heart motion from 3D echocardiographic image sequence. On the basis of this method we have developed several visualization techniques that enable qualitative assessments of heart motions abnormalities. Together with quantitative measurements they may be become a useful tools in daily clinical practice