Search results for " exploration"
showing 10 items of 169 documents
Optimal Trajectories for Spacecraft Rendezvous
2007
The efficient execution of a rendezvous maneuver is an essential component of various types of space missions. This work describes the formulation and numerical investigation of the thrust function required to minimize the time or fuel required for the terminal phase of the rendezvous of two spacecraft. The particular rendezvous studied concerns a target spacecraft in a circular orbit and a chaser spacecraft with an initial separation distance and separation velocity in all three dimensions. First, the time-optimal rendezvous is investigated followed by the fuel-optimal rendezvous for three values of the max-thrust acceleration via the sequential gradient-restoration algorithm. Then, the ti…
Syntheses, Structures, Magnetic Properties, and Density Functional Theory Magneto-Structural Correlations of Bis(μ-phenoxo) and Bis(μ-phenoxo)-μ-acet…
2013
The bis(mu-phenoxo) (FeNiIII)-Ni-II compound [Fe-III(N-3)(2)LNiII(H2O)(CH3CN)](ClO4) (1) and the bis(mu-phenoxo)-mu-acetate/bis(mu-phenoxo)-bis(mu-acetate) (FeNiII)-Ni-III compound {[Fe-III(OAc)LNiII(H2O)(mu-OAc)](0.6)center dot[(FeLNiII)-L-III(mu-OAc)(2)](0.4)}(ClO4)center dot 1.1H(2)O (2) have been synthesized from the Robson type tetraiminodiphenol macrocyclic ligand H2L, which is the [2 + 2] condensation product of 4-methyl-2,6-diformylphenol and 2,2'-dimethy1-1,3-diaminopropane. Single-crystal X-ray structures of both compounds have been determined. The cationic part of the dinuclear compound 2 is a cocrystal of the two species [Fe-III(OAc)LNiII(H2O)(mu-OAc)](+) (2A) and [(FeLNiII)-L-I…
CVC AND INNOVATION PERFORMANCE: THE EFFECT OF TECHNOLOGICAL DISTANCE WITH STARTUPS AND COINVESTORS
2018
Firms are increasingly opening their boundaries by engaging in corporate venture capital (CVC) programs as potential gateway into knowledge and technologies of innovative startups. By investing in promising startups across diverse industries with different technological knowledge from the knowledge base of the investing corporate, CVC programs constitute a vehicle for corporates to both exploit and explore innovation opportunities. We first examine the relationship between more explorative CVC investments portfolio and the innovation performance of the corporate. Then, we argue that when syndicating the CVC investments with a co-investor, the portfolio of syndication partners may affect the…
The TES-based cryogenic anticoincidence detector for IXO: First results from large area prototypes
2010
The technique which combines high resolution spectroscopy with imaging capability is a powerful tool to extract fundamental information in X-ray Astrophysics and Cosmology. TES (Transition Edge Sensors)-based microcalorimeters match at best the requirements for doing fine spectroscopy and imaging of both bright (high count rate) and faint (poor signal-to-noise ratio) sources. For this reason they are considered among the most promising detectors for the next high energy space missions and are being developed for use on the focal plane of the IXO (International X-ray Observatory) mission. In order to achieve the required signal-to-noise ratio for faint or diffuse sources it is necessary to r…
A Robotic Humanoid for Information Exploration on Cultural Heritage Domain
2020
The work presented here illustrates an humanoid robot capable of interacting with an human user within the Cultural Heritage domain. Two different and complementary AI approaches, namely sub-symbolic and symbolic, have been implemented and combined together to design the framework of a robot having both rational and intuitive capabilities. Furthermore, the robot is capable of providing information expressively and of adapting its behavior according to the emotional content of the artworks descriptions. This could make the robot more effective in providing information and entertaining the users.
Co-simulation of bio-inspired multi-agent algorithms
2020
This paper reports on the co-simulation of a team of robots deployed in an exploration task, coordinated by a bio-inspired exploration algorithm. The co-simulation integrates the high-level exploration algorithm with detailed implementations of the robot controllers and kinematic models. Co-simulation results are used to find and correct mismatches between submodels.
Influence of surface processes and initial topography on lateral fold growth and fold linkage mode
2015
Elongation of randomly distributed fold segments and their potential linkage are important for hydrocarbon exploration because it can greatly influence the morphology of the reservoir and both migration and accumulation of hydrocarbons in antiformal traps. Here we study the effects of surface processes and the presence of a topographic slope on the different linkage modes that can occur, and how these parameters affect the required horizontal offset for perturbations to link. The proposed numerical model represents a sedimentary cover detached over a much weaker basal decollement layer. The upper surface is modified by mass redistribution, which is achieved by a combination of fluvial and h…
Ecclesia carinensis. Una sede episcopale alle origini del cristianesimo fra Palermo e Lilibeo; La catacomba paleocristiana di Villagrazia di Carini
2020
The Early Christian cemetery discovered by chance in Villagrazia di Carini in 1899, then forgotten and negletted, has been brought to light from the year 2000 to today thanks to the systematic teamwork of the University of Palermo and the Pontificia Commissione di Archeologia Sacra (PCAS). The unexpected dimension of the site, the largest underground cemetery of Early Christianity so far known in western Sicily, has finally allowed the historiographical debate to find a meeting point on the age-old problem of the existence of ecclesia carinensis, an Early Byzantine diocese attested by the written sources up to the eighth century and disappeared after the centuries of the Islamic domination …
Do soils exist outside Earth?
2010
Abstract On Earth, soils form thanks to the combined action of at least five factors: parent rock, climate, topography, biota, and time. However, the necessity of biota as unavoidable soil forming factor is debated, as important parts of our planet experiencing extreme climates host virtually life-free soils with advanced horizonation. Now that space exploration has greatly expanded our understanding of the Solar System, providing consistent evidences that the loose, unconsolidated "skin" of some nearby rocky bodies is lifeless, it is time to establish if the latter can be considered to be soil in a pedological sense. Our feeling is that, since the concept of soil chiefly bases on the occur…
Typification of the name Senecio pygmaeus (Asteraceae), with some additional taxonomic and phytogeographic remarks
2023
A thorough research on the scientific activity of Guglielmo Gasparrini, Giovanni Gussone and Augustin Pyramus De Candolle allowed the authors to adress a research in several European herbaria looking for the type of the name Senecio pygmaeus DC. The original specimen sent by Gussone and mentioned in the protologue by Candolle is still kept at G-DC and is designated as the lectotype, whilst three other herbarium sheets, preserved at NAP-GUSS, PAL and PAV herbaria respectively, in all probability belong to the same gathering, and are considered as isolectotypes. The authors provide an updated description of this taxon in order to better point out its diagnostic characters. However, further bi…