183 research outputs found

    The Asolant/Rubin-5 Technology Demonstration Mission - System Description and First Flight Results

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    This paper addresses the Asolant/Rubin-5 flight experiment conducted onboard the upper stage of a Cosmos rocket in late 2005. The main objective of the project was to flight-qualify a newly developed combined solar cell/antenna device, the so-called Advanced SOLar ANTenna (ASOLANT) technology. In order to assess both, the reception as well as emission of R/F signals, two different devices were involved in the mission. One was linked to a space-borne Phoenix-S GPS receiver to examine the receiving performance. A second device was designed to send out S-Band beacon signals generated by the SAFIR-S amateur radio transmitter to evaluate the radiation characteristics. Moreover, both ASOLANT devices supplied the electrical power for the onboard systems. Telecommand and telemetry functionalities were provided by an ORBCOMM communicator making use of the ORBCOMM satellite network to relay data between space and ground. This unit, furthermore, served as onboard computer. The experiment was launched along with eight multinational payload satellites. It was designed to remain attached to the rockets upper stage after burnout. Due to a separation failure of one of the copassengers, the primary mission objectives could not be fully met. Nevertheless, a sufficient number of data was retrieved to confirm the good overall performance of the ASOLANT devices. Roughly ten month after the launch, still most system components are operational and experiment data are transmitted to ground. Following a description of the main flight system components and the overall ystem architecture, the paper summarizes the hitherto obtained experiment results

    Soft-switching modular multilevel converters for efficient grid integration of renewable sources

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    The Modular Multilevel Converter (MMC) concept is a modern energy conversion structure that stands out for a number of interesting features that opens wide application chances in Power Systems, for example for efficient grid integration of renewable sources. In these high-voltage, high-power application fields, a high efficiency is mandatory. In this regard, an interesting and promising development opportunity could be to make soft-switching the elementary converters of the submodules (cells), half H-bridges or full H-bridges, obtaining at the same time the advantage of increasing the switching frequency. The ARCP or the AQRDCL soft-switching topologies appear adequate for this purpose. This paper is dedicated to examining these development possibilities

    Heterogeneous Catalytic Approaches in C-H Activation Reactions

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    This review summarizes the development of user-friendly, recyclable and easily separable heterogeneous catalysts for C–H activation during the last decade until December 2015

    Do Lifestyle Interventions before Gastric Bypass Prevent Weight Regain after Surgery? A Five-Year Longitudinal Study

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    It is unclear whether weight loss (WL) achieved by means of lifestyle interventions (LSIs) before bariatric surgery (BS) can improve long-term WL outcomes after surgery. We aimed to assess the impact of a structured LSI on WL% after gastric bypass (GBP). Two groups of patients were selected from a large cohort of participants with obesity who underwent GBP surgery at Santa Maria Nuova Hospital (Reggio Emilia, Italy). The groups were categorized as those who have or have not received LSI prior to GBP. The LSI group included 91 participants (cases) compared to 123 participants (controls) in the non-LSI group. WL% was measured at follow-up times of 1, 3, 6, 12, 24, 36, 48, and 60 months. The LSI group achieved a clinically significant WL% (-7.5%) before BS, and at the time of surgery, the two groups had similar body weights and demographic statuses. At all points, until the 24-month follow-up, the two groups displayed similar WLs%. With regard to the longer follow-ups, the LSI group maintained weight loss until the last timepoint (60 months), whereas the non-LSI group experienced weight regain at 36, 48, and 60 months. In a real-world context, a structured behavioral LSI prior to GBP seems to prevent longer-term weight regain

    Rationalist architecture in rural villages: petro-morphological characterization of natural asbestos fibers in decorative plasters used for artificial stones

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    At the beginning of the twentieth century, artificial stones became commonly used as structural building materials, masonry materials, and architectural decorative elements. The main purpose of this work was to characterize the building materials used in a historical building in Codigoro, a small town near Ferrara, northeastern Italy. This building was constructed according to the Italian rationalist rules for monumental architecture and is an example of the rationalist architecture found in rural villages, which uses innovative materials and decorations including artificial stone. The samples analyzed in this work were imitation natural stone, such as “fake travertine” and “fake Ceppo di Grè”, composed of reinforced concrete slabs coated with white mortar. Asbestos minerals have been observed in the fillers in these materials. Petrographic, mineralogical, and chemical characterization of samples of artificial stones and concrete was performed with optical transmitted light microscopy, scanning electron microscopy–energy dispersive spectroscopy, and X-ray diffraction analyses. The results revealed chemical and biological degradation in almost all the artificial stones examined and enabled identification of the presence of calcite, iron oxychloride complexes, and asbestos lizardites used as fillers in two of the analyzed samples. This study aimed to describe a general investigation methodology used to examine the artificial stone façades of the Ex Casa del Fascio of Codigoro, whose architecture is particularly representative of the rationalist architecture in rural villages. The results highlight the relevance of compatible and suitable conservation measures that should be monitored during all restoration interventions to minimize post-degradation fracturing and transformation into elements harmful to human health and the environment

    Impact of gas hardening on the population properties of hierarchical black hole mergers in AGN disks

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    Hierarchical black hole (BH) mergers in active galactic nuclei (AGNs) are unique among formation channels of binary black holes (BBHs) because they are likely associated with electromagnetic counterparts and can efficiently lead to the mass growth of BHs. Here, we explore the impact of gas accretion and migration traps on the evolution of BBHs in AGNs. We have developed a new fast semi-analytic model, which allows us to explore the parameter space while capturing the main physical processes involved. We find that effective exchange of energy and angular momentum between the BBH and the surrounding gas (hereafter, gas hardening) during inspiral greatly enhances the efficiency of hierarchical mergers, leading to the formation of intermediate-mass BHs (up to 10.000 solar masses) and triggering spin alignment. Moreover, our models with efficient gas hardening show both an anti-correlation between BBH mass ratio and effective spin, and a correlation between primary BH mass and effective spin. In contrast, if gas hardening is inefficient, the hierarchical merger chain is already truncated after the first two or three generations. We compare the BBH population in AGNs with other dynamical channels as well as isolated binary evolution.Comment: 21 pages, 15 figures, submitted to A&A, comments welcom

    PARA UMA CRĂŤTICA DA AUTORIDADE

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    Monitoraggio Ambientale di un'Area Contaminata nella Provincia di Pavia

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    Lo scopo di tale indagine è stato quello di valutare il livello di contaminazione, l'estensione e l'entità di contaminanti presenti nei suoli superficiali a suo tempo riscontrati mediante il Progetto Pavia. Il monitoraggio ambientale ha interessato un'area di circa 12 ettari che si trova nel comune di Carpiano. Complessivamente sono state identificate 33 aree di campionamento dove sono stati prelevati campioni di suolo sino alla profondità di 30 cm. In ciascun campione di suolo, dopo adeguati trattamenti, è stata valutata la concentrazione di metalli pesanti, metalloidi, macroelementi, sostanza organica, pH, densità apparente, contenuto d'acqua. In alcuni campioni, precisamente 11, si è analizzata la concentrazione di diossine e furani e si è approntato uno studio che ha visto l'utilizzo dei batteri e dei loro prodotti. Lo studio condotto attraverso l'uso dei batteri ha evidenziato anomalie in alcuni punti ad elevata contaminazione. I risultati analitici ottenuti hanno identificato la presenza di una importante contaminazione di metalli pesanti, metalloidi, diossine e furani che interessa un area di alcuni ettari. Tale livello di contaminazione, per la presenza di sostanza organica e per valori ridotti di acidità dei suoli stessi, potrà arrecare danni ingenti all'ambiente.JRC.DDG.H.7-Land management and natural hazard

    The emerging role of ferroptosis in liver cancers

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    : Liver cancer represents a global health challenge with worldwide growth. Hepatocellular carcinoma (HCC) is the most common type of liver cancer. Indeed, approximately 90% of HCC cases have a low survival rate. Moreover, cholangiocarcinoma (CC) is another malignant solid tumor originating from cholangiocytes, the epithelial cells of the biliary system. It is the second-most common primary liver tumor, with an increasing course in morbidity and mortality. Tumor cells always show high metabolic levels, antioxidant modifications, and an increased iron uptake to maintain unlimited growth. In recent years, alterations in iron metabolism have been shown to play an important role in the pathogenesis of HCC. Several findings show that a diet rich in iron can enhance HCC risk. Hence, elevated iron concentration inside the cell may promote the development of HCC. Growing evidence sustains that activating ferroptosis may potentially block the proliferation of HCC cells. Even in CC, it has been shown that ferroptosis plays a crucial role in the treatment of tumors. Several data confirmed the inhibitory effect in cell growth of photodynamic therapy (PDT) that can induce reactive oxygen species (ROS) in CC, leading to an increase in malondialdehyde (MDA) and a decrease in intracellular glutathione (GSH). MDA and GSH depletion/modulation are crucial in inducing ferroptosis, suggesting that PDT may have the potential to induce this kind of cell death through these ways. A selective induction of programmed cell death in cancer cells is one of the main treatments for malignant tumors; thus, ferroptosis may represent a novel therapeutic strategy against HCC and CC
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