51 research outputs found
A review of LCA assessments of forest-based bioeconomy products and processes under an ecosystem services perspective
The emergence of politically driven bioeconomy strategies worldwide calls for considering the ecological issues associated with bio-based products. Traditionally, life cycle analysis (LCA) approaches are key tools used to assess impacts through product life cycles, but they present limitations regarding the accounting of multiple ecosystem service-related issues, at both the land-use and supply chain levels. Based on a systematic review of empirical articles, this study provides insights on using LCA assessments to account for ecosystem service-related impacts in the context of bioeconomy activities. We address the following research questions: what is the state of the art of the literature performing LCA assessments of forest-based bioeconomy activities, including the temporal distribution, the geographic areas and products/processes at study, and the approaches and methods used? 2. Which impacts and related midpoints are considered by the reviewed studies and what types of ecosystem service- related information do they bear? Out of over 600 articles found through the Scopus search, 155 were deemed relevant for the review. The literature focuses on North-America and Europe. Most of the articles assessed the environmental impact of lower-value biomass uses. Climate change was assessed in over 90% of the studies, while issues related to ozone, eutrophication, human toxicity, resource depletion, acidification, and environmental toxicity were assessed in 40% to 60% of the studies. While the impact categories accounted for in the reviewed LCA studies bear information relevant to certain provisioning and regulating services, several ecosystem services (especially cultural ones) remain unaccounted for. The implications of our study are relevant for professionals working in the ecosystem services, circular bioeconomy, and/or LCA communities. (C) 2019 The Authors. Published by Elsevier B.V.Peer reviewe
Pluronic® P123/F127 mixed micelles delivering sorafenib and its combination with verteporfin in cancer cells
Here, we developed Pluronic® P123/F127 (poloxamer) mixed micelles for the intravenous delivery of the anticancer drug sorafenib (SRB) or its combination with verteporfin (VP), a photosensitizer for photodynamic therapy that should complement well the cytotoxicity profile of the chemotherapeutic. SRB loading inside the core of micelles was governed by the drug:poloxamer weight ratio, while in the case of the SRB-VP combination, a mutual interference between the two drugs occurred and only specific ratios could ensure maximum loading efficiency. Coentrapment of SRB did not alter the photophysical properties of VP, confirming that SRB did not participate in any bimolecular process with the photosensitizer. Fluorescence resonance energy-transfer measurement of micelles in serum protein-containing cell-culture medium demonstrated the excellent stability of the system in physiologically relevant conditions. These results were in line with the results of the release study showing a release rate of both drugs in the presence of proteins slower than in phosphate buffer. SRB release was sustained, while VP remained substantially entrapped in the micelle core. Cytotoxicity studies in MDA-MB231 cells revealed that at 24 hours, SRB-loaded micelles were more active than free SRB only at very low SRB concentrations, while at 24+24 hours a prolonged cytotoxic effect of SRB-loaded micelles was observed, very likely mediated by the block in the S phase of the cell cycle. The combination of SRB with VP under light exposure was less cytotoxic than both the free combination and VP-loaded micelles + SRB-loaded micelles combination. This behavior was clearly explainable in terms of micelle uptake and intracellular localization. Besides the clear advantage of delivering SRB in poloxamer micelles, our results provide a clear example that each photochemotherapeutic combination needs detailed investigations on their particular interaction, and no generalization on enhanced cytotoxic effects should be derived a priori
Improved Methodology to Estimate the Power Transfer Efficiency in an Inductively Coupled Radio Frequency Ion Source
The International Thermonuclear Experimental Reactor neutral beam injector includes an ion source which can produce D− ion beams for 1 h, accelerated at the energy of 1 MeV. An ion source consists of a driver where the plasma is produced by the application of the radio frequency (RF) power to an inductive coil. This paper presents an improved methodology which provides an estimation of the power transfer efficiency to the plasma of the driver. The developed methodology is based on different mechanisms which are responsible for the plasma heating (ohmic and stochastic) and an electrical model describing the power transfer to the plasma. As a first approximation in a previous work, a transformer model was assumed as an electrical model. In this paper, a main improvement is introduced based on the development of a multi-filament model which takes into account the mutual coupling between the RF coil, the plasma, and the passive metallic structure. The methodology is applied to the negative ion optimization 1 (NIO1), a flexible negative ion source, currently in operation at Consorzio RFX, Italy. The results from the two models, transformer and multi-filament, are presented and compared in terms of plasma equivalent resistance and power transfer efficiency. It is found that results obtained from both the transformer and the multi-filament model follow the same trend in comparison with the applied frequency and the other plasma parameters like electron density, temperature, and gas pressure. However, lower values of the plasma equivalent resistance and power transfer efficiency are observed with the multi-filament model. The multi-filament model reproduces a more realistic experimental scenario where the power losses due to the generation of the eddy currents in the metallic structure are considered
A new method for measuring angle-resolved phases in photoemission
Quantum mechanically, photoionization can be fully described by the complex
photoionization amplitudes that describe the transition between the ground
state and the continuum state. Knowledge of the value of the phase of these
amplitudes has been a central interest in photoionization studies and newly
developing attosecond science, since the phase can reveal important information
about phenomena such as electron correlation. We present a new
attosecond-precision interferometric method of angle-resolved measurement for
the phase of the photoionization amplitudes, using two phase-locked Extreme
Ultraviolet pulses of frequency and , from a Free-Electron
Laser. Phase differences between one- and two-photon
ionization channels, averaged over multiple wave packets, are extracted for
neon electrons as a function of emission angle at photoelectron energies
7.9, 10.2, and 16.6 eV. is nearly constant for emission
parallel to the electric vector but increases at 10.2 eV for emission
perpendicular to the electric vector. We model our observations with both
perturbation and \textit{ab initio} theory, and find excellent agreement. In
the existing method for attosecond measurement, Reconstruction of Attosecond
Beating By Interference of Two-photon Transitions (RABBITT), a phase difference
between two-photon pathways involving absorption and emission of an infrared
photon is extracted. Our method can be used for extraction of a phase
difference between single-photon and two-photon pathways and provides a new
tool for attosecond science, which is complementary to RABBITT
Overview on electrical issues faced during the SPIDER experimental campaigns
SPIDER is the full-scale prototype of the ion source of the ITER Heating
Neutral Beam Injector, where negative ions of Hydrogen or Deuterium are
produced by a RF generated plasma and accelerated with a set of grids up to
~100 keV. The Power Supply System is composed of high voltage dc power supplies
capable of handling frequent grid breakdowns, high current dc generators for
the magnetic filter field and RF generators for the plasma generation. During
the first 3 years of SPIDER operation different electrical issues were
discovered, understood and addressed thanks to deep analyses of the
experimental results supported by modelling activities. The paper gives an
overview on the observed phenomena and relevant analyses to understand them, on
the effectiveness of the short-term modifications provided to SPIDER to face
the encountered issues and on the design principle of long-term solutions to be
introduced during the currently ongoing long shutdown.Comment: 8 pages, 12 figures. Presented at SOFT 202
Combined Capacitor-Resistor Energy Transfer System to Increase Plasma Current in RFX-Mod2
RFX-mod is an experimental fusion device, which contributes to plasma physics studies both in reversed field pinch (RFP) and tokamak configurations. Its high flexibility, due to an active magnetohydrodynamic (MHD) control system and the modular coils power supply (CPS) system, allowed operating RFX-mod in a wide range of experimental conditions with a plasma current up to 2 MA. Experiments with such high plasma current allowed the study on new promising confinement regimes, dominated by a self-organization process with the generation of a helical structure in the plasma core. Presently, RFX-mod is under a significant upgrade (RFX-mod2) to extend the operational scenarios increasing the proximity between the conductive shell and the plasma. This main modification of the magnetic front-end, together with other main improvements, is expected to increase the performance of the machine in both magnetic configurations. In the frame of the studies to exploit the new potential of RFX-mod2 achieving a higher plasma current and longer flat-top duration, a solution based on additional magnetic energy storage has already been proposed. The study of RFP physics at higher plasma current could be crucial to confirm positive trends, such as electron temperature and persistence of quasi single helicity states with the plasma current, and to explore and achieve improved confinement states. This article presents an alternative reconfiguration of the poloidal power supply system of RFX-mod2 based on a combined resistor-capacitor energy transfer system. This system allows to store energy in capacitor banks during the first phase of the plasma current ramp-up and release it to the plasma when the magnetizing current changes polarity, driving the plasma current over 2.5 MA. The proposed upgrade does not involve radical poloidal CPS modifications, maintaining the present converters number and ratings and remaining within the power limits of the main power transformers (300 MVA)
Feasibility study of RFX-mod2 performance improvement by additional magnetic energy storage
none4noneLunardon, Francesco; Maistrello, Alberto; Gaio, Elena; Piovan, RobertoLunardon, Francesco; Maistrello, Alberto; Gaio, Elena; Piovan, Robert
Power Amplifiers Based on SiC Technology for MHD Mode Control in Fusion Experiments
The effective control of MHD instabilities in fusion experiments by means of actively controlled coils calls for challenging dynamic requirements to the relevant power supply (PS) systems. This paper reports on the case of the PS system for resistive wall mode control in the JT-60SA satellite tokamak, where analyses showed the difficulty of satisfying the demanding requirements in terms of high current bandwidth (3 kHz) and short latency (<50 s) with a simple H-bridge topology adopting standard IGBT. On the contrary, the use of Si–SiC IGBT with the same topology can allow meeting the specifications, as demonstrated by the development and test of such a power amplifier, rated for 300 Apk and 240 V
- …