665 research outputs found
Dialogues on Architecture
No full textDialogues on Architecture is a series of dialogues between researchers and practitioners, who are embracing the intellectual model of high technology and are involved in its advancement and application in architecture. Dialogue #4 focuses on the technology transfer between on-and off-Earth research and its impact on society, and in particular on industry and education. The dialogue takes place between Henriette Bier (HB), Paul Chan (PC), Advenit Makaya (AM), and Angelo Cervone (AC).History, Form & AestheticsDesign & Construction ManagementSpace Systems Egineerin
Dry deposition of particle on urban areas
No full textDry deposition process is recognized as an important pathway among the removal processes of radioactive pollutants in atmosphere. There is not a unique and accepted theoretical description of involved dry deposition phenomena due to the complexity of the fluid-dynamic processes that influence the deposition flux, but also because there is a lack of experimental data covering all scenarios of interest. In this paper, that is the result of a National Research Program a research activity conducted by DEIM Department of the University of Palermo and ENEA and funded by the Italian Minister of Economic Development, a new schema for parameterization of particle dry deposition velocity on urban area is proposed. The work required comparisons with some experimental data reported in literature for different particle deposition scenarios. The results show that the proposed approach can catch some aspects of phenomena involved in dry deposition processes for the examined environmental conditions with good agreement
Extracellular H2O2 induced by oligogalacturonides is not ivolved in the inhibition of the auxin-regulated rolB gene expression in tobacco leaf explants
No full texta-1,4-Linked oligogalacturonides (OGs) inhibit auxin-regulated
transcriptional activation of a rolB-b-glucuronidase (GUS) gene
fusion in tobacco (Nicotiana tabacum) leaf explants (D. Bellincampi,
M. Cardarelli, D. Zaghi, G. Serino, G. Salvi, C. Gatz, F.
Cervone, M.M. Altamura, P. Costantino, G. De Lorenzo [1996]
Plant Cell 8: 477–487). In this paper we show that inhibition by OGs
is very rapid, with a short lag time, and takes place even after rolB
promoter activation has initiated. OGs also induce a transient and
catalase-sensitive accumulation of H2O2 in the leaf explant culture
medium. OGs with a degree of polymerization from 12 to 15 are
required for both the inhibition of the auxin-induced rolB-driven
accumulation of GUS and the induction of H2O2 accumulation.
However, OG concentration for half-maximal induction of H2O2
accumulation is approximately 3-fold higher than that for halfmaximal
inhibition of rolB promoter activity. The inhibition of rolB
promoter activity is not influenced by the addition of catalase or
superoxide dismutase, suggesting that H2O2 and superoxide are not
involved in this effect. A fungal oligo-b-glucan elicitor induces
extracellular H2O2 accumulation at comparable or higher levels
than those observed with OGs, but does not prevent the auxininduced
accumulation of GUS. We conclude that H2O2 produced
upon treatment with OGs is not involved in the inhibition of the
auxin-induced expression of the rolB gene
Competitive inhibition of the auxin-induced elongation by α-D-oligogalacturonides in pea stem segments
No full textFEMLCORE-CATHARE coupling on Salome platform
No full textIn this report we present the development of the FemLCore-Cathare code coupling for the simulation of the dynamics of the primary loop of a lead-cooled nuclear reactor. In the framework of a multi-scale and multi-physic approach we develop a class interface for the FemLCore modules and another for the Cathare system code that allow data transfer with a supervisor function. The numerical coupled solution is obtained by using the defective coupling approach. The problem is solved over a mono-dimensional mesh by using the system code and its solution is then corrected over the overlapping three-dimensional domain. The Cathare code solves and generates boundary conditions for the FemLCore modules in order to receive back the three-dimensional solution corrections in the form of appropriate mass, momentum and energy sources. The input-output formats for meshes and solutions are in MedMem format. Data are exchanged at each time step through a supervisor code written in c++ language. Two coupling tests are performed. In the first test a simple three-dimensional core model reactor and a primary mono-dimensional loop, which consists of a pump and a heat exchanger, are considered. In the second test a three-dimensional CFD-porous reactor with core and lower-upper plenum is coupled with a primary mono-dimensional loop
Assessment of the Propulsive Performance of Fuel Vapor Pressurized Hydrogen Peroxide-Ethane Rocket Engines
No full textIn the last years low-toxicity “green” storable liquid propellants have become considerably more attractive as possible substitutes for nitrogen oxides and hydrazines. The main advantage of “green” propellants is represented by the significant cost savings associated with the drastic simplification of the health and safety protection procedures necessary during propellant production, storage and handling. Fuel Vapor Pressurization (FVP) technology of “green” bipropellant rocket engines potentially offers very significant additional advantages in terms of system cost, complexity, reliability, safety and mass, with practically no penalty in propulsive performance compared to traditional storable propellants such as mixed nitrogen oxides and hydrazines. Pioneering FVP experiments were carried out by Goddard, Wyld and others. Detailed studies have been conducted and several tests have been successfully performed since 1994 in the US, but no such experience is presently available in Europe, nor FVP has ever attained flight readiness anywhere in the world. The main characteristics of the FVP system examined in this work consist in the use of storable, non-toxic, inexpensive, non hypergolic, high-energy propellants such as hydrogen peroxide (HP, H2O2) and ethane (C2H6) and in the storage of these propellants in a single lightweight tank, using a flexible diaphragm or a bladder to separate the fuel from the oxidizer and a catalytic reactor to decompose the hydrogen peroxide before mixing and combustion with ethane. This configuration therefore yields a very simple and yet highly efficient and reliable propulsion system by eliminating the cost, the weight and complexity of propellant tanks and pressurization bottles, pressure and flow regulators and ignition systems. These advantages are of special relevance in low- or mediumthrust rocket engines for the rapidly expanding market of “small” space missions and led the authors to focus on the analysis and assessment of propulsion systems operating according to this concept. The present paper reports therefore the preliminary evaluation of fuel vapor pressurized H2O2-C2H6 rocket propulsion systems. The results of the analysis confirm that the development of FVP technology may represent a significant contribution to the containment of the propulsion cost of small- and medium-size spacecrafts
A Simplified Analytical Model for Evaluating the Noncavitating Performance of Axial Inducers
No full textThe present paper describes an analytical model for the preliminary prediction of the noncavitating flow field and performance of helical inducers. The proposed model is based on the traditional troughflow theory approximations with empirical corrections for outlet flow deviation and hydraulic losses due to inlet incidence effects and friction in the blade channels. Unlike most classical models, it allows – even if under still rather restrictive assumptions – for the prediction of the radial and circumferential flow velocity fields at the inducer exit section and for the approximate evaluation of the head coefficient as a function of the flow coefficient in terms of the static pressure rise generated by the inducer. The results are presented of the model validation by comparison with the experimental data obtained for several inducers tested in different facilities worldwide
The Language of Derogation and Hate: Functions, Consequences, and Reappropriation
No full textOver the last decades, the use of explicit derogatory language (e.g., hate speech, slurs, micro-insults) has risen in many countries. We provide an overview on blatant language discrimination, including its psychological antecedents and consequences. After presenting a working definition of derogatory language and describing its prevalence, we discuss the social functions it serves and the role it plays in identity protection, in legitimizing group hierarchies, and in establishing and enforcing group norms. Drawing from both the socio-cognitive and discursive traditions in social psychology, it is argued that the language people are exposed to and the language they employ, shape the way they think and construct reality. We also consider two ways in which targeted groups may respond to derogatory language, specifically confrontation and reappropriation. Finally, we address challenges for future research, in particular the need for more cross disciplinary research to ebb the growing proliferation of hate speech on digital media which has become a global international concern
The Radiation Environment and effects analysis of the LUMIO Mission
No full textThe Earth-Moon system is constantly bombarded by meteoroids of different size and impact speed. Observation of the impacts on the Moon can enable thorough characterization of the Lunar meteoroid flux, which is similar to that of the Earth. While Earth-based Lunar observations are restricted by weather, geometric and illumination conditions, a Lunar-based observation campaign can improve the detection rate and, when observing the Lunar far side, complement in both space and time the observations taken from Earth. The Lunar Meteoroid Impact Observer (LUMIO), one of the two winning concepts of the ESA SysNova Lunar CubeSats for Exploration challenge, is a mission designed to observe, quantify, and characterize the micro-meteoroid impacts on the Lunar far side. It is based on a 12U CubeSat that carries the LUMIO-Cam, a custom-designed optical instrument capable of detecting light flashes in the visible spectrum. The spacecraft is placed on a halo orbit about the Earth–Moon L2 point, where permanent full-disk observation of the Lunar far side can be performed with excellent quality, given the absence of Earth background noise. After passing Phase 0 and an independent feasibility study in the ESA Concurrent Design Facility, the mission has successfully completed its Phase A in March 2021. Although the Phase 0 design of the LUMIO spacecraft was assessed as feasible by the ESA CDF study, a number of critical issues were identified, which have been tackled by the Phase A design. The paper presents the outcome of this Phase A design effort for the LUMIO spacecraft. Particularly relevant changes or updates in the spacecraft design include: a consolidated design of the LUMIO-Cam, with longer baffle for straylight protection; a set of ADCS sensors and actuators with increased redundancy; a combination of Direct-to-Earth communication and inter-satellite link with a mothership in Lunar orbit; use of Earth ranging to complement and validate the current innovative autonomous navigation strategy based on optical observations of the Moon by means of the LUMIO-Cam; re-assessment of the COTS components selection for the power and propulsion systems.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Space Systems Egineerin
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