Search results for "Planetary Science"
showing 10 items of 4367 documents
Flow resistance in gravel-bed channels with large-scale roughness
2003
A previously published mixing length (ML) model for evaluating the Darcy–Weisbach friction factor for a large-scale roughness condition (depth to sediment height ratio ranging from 1 to 4) is briefly reviewed and modified (MML). Then the MML model and a modified drag (MD) model are experimentally tested using laboratory measurements carried out for gravel-bed channels and large-scale roughness condition. This analysis showed that the MML gives accurate estimates of the Darcy–Weisbach coefficient and for Froude number values greater than 0·5 the MML model coincides with the ML one. Testing of the MD model shows limited accuracy in estimating flow resistance. Finally, the MML and MD models are com…
Oxygen-carrying v. non-oxygen-carrying colloidal blood substitutes in schock
1982
Loss of more than 10-15 per cent of the circulating blood causes a corresponding fall in filling pressure and a marked reduction in minute volume. In order to combat a fall in the minute volume, catecholamines are liberated, the stimulating components of these cause a rise in vessel tone. In spite of the blood volume being reduced by blood loss, filling pressure and minute volume are restored by compensating mechanisms as long as the volume lost is not enough to exceed the autoregulative capacity. Even with a blood loss of 10-15 per cent, full compensation is not achieved without replenishing the blood volume unless the fluid lost from the vascular bed is less than I0 per cent of the total.…
Permian-Cenozoic deep-water carbonate rocks of the Southern Tethyan Domain. The case of Central Sicily
2016
We present an integrated stratigraphy of the outcropping and buried Permian-Cenozoic deep-water carbonate successions, forming some of the tectonic units mostly buried beneath the Late Neogene sedimentary cover in the fold and thrust belt of Central Sicily. Three main successions, pertaining to the well known Lercara, Imerese and Sicanian domains, have been reconstructed on the basis of a detailed facies analysis, seismostratigraphic interpretation, bio -stratigraphy (mostly based on palynological data) and comparison between outcropping and subsurface deep-water sediments. The main results reveal a continuous sedimentation of the deep-water Southern Tethyan Sicilian succession since the Pe…
A pre-processing and network analysis of GPS tracking data
2020
Global Positioning System (GPS) devices afford the opportunity to collect accurate data on unit movements from temporal and spatial perspectives. With a special focus on GPS technology in travel surveys, this paper proposes: (1) two algorithms for the pre-processing of GPS data in order to deal with outlier identification and missing data imputation; (2) a clustering approach to recover the main points of interest from GPS trajectories; and (3) a weighted-directed network, which incorporates the most relevant characteristics of the GPS trajectories at an aggregate level. A simulation study shows the goodness-of-fit of the imputation data algorithm and the robustness of the clustering algori…
Collaborative development of a CPS-based production system
2019
Abstract The paper describes the collaborative processes and technologies used to develop a prototype for a Cyber-Physical Production System of USB sticks. The development of this system follows the model-based approach where co-simulations of different components, detailed at different level of abstractions, serve as a basis for structured dialogue between specialised teams and agreement on shared interactions. The focus is primarily on the co-simulation technology, allowing a gradual increase of fidelity and independent testing and validation of the composing subsystems. This technology may be equally complemented with group decision-making tools to better support the collaboration during…
School choice criteria and school segregation in the city of Valencia
2022
El objetivo de este estudio es conocer cuáles son los patrones que intervienen en la elección de centro escolar y detectar los factores sociodemográficos, económicos y de localización que subyacen tras ellos. Para ello, se ha realizado una encuesta a la demanda potencial de los centros públicos que imparten el segundo ciclo de educación infantil en la ciudad de Valencia. Los resultados indican que el principal criterio de elección de centro escolar es la proximidad entre el hogar y el colegio, y que el modo de desplazamiento más utilizado es el peatonal. Sin embargo, los costes de desplazamiento y los medios utilizados están directamente relacionados con las características socioeconómicas …
Development of a Model to Estimate the Risk of Emission of Greenhouse Gases from Forest Fires
2022
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Synthesis of complex organic molecules in soft x-ray irradiated ices
2019
We study the chemical evolution of H2O:CO:NH3 ice mixtures irradiated with soft X-rays, in the range 250-1250 eV. We identify many nitrogen-bearing molecules such as e.g., OCN-, NH4+ , HNCO, CH3CN, HCONH2, and NH2COCONH2. Several infrared features are compatible with glycine or its isomers. During the irradiation, we detected through mass spectroscopy many species desorbing the ice. Such findings support either the infrared identifications and reveal less abundant species with not clear infrared features. Among them, m/z = 57 has been ascribed to methyl isocyanate (CH3NCO), a molecule of prebiotic relevance, recently detected in protostellar environments. During the warm up after the irradi…
Study on the Evolution of Defense Expenses in Nato Member States for the Period 2010–2020. “Free Rider” behavior among Allies
2021
Abstract This paper proposes a longitudinal study on the analysis of defense spending of NATO member states in the years 2010-2020. It also aims to identify the emergence of a possible “free-rider” behavior among alliance members. This behavior occurs when some members may be tempted to allocate a low level of defense spending. Defense spending is an important component of each state’s budget, which ensures a vital function of states, namely the national defense function. When the defense is carried out in military-type alliances, and the number of members is large, there is an increased possibility of observing a “free-rider” type behavior between the members of the alliances. To observe t…