89,795 research outputs found
Sistemi di gestione dell'energia e strategie di ottimizzazione per l'integrazione dei veicoli elettrici considerando gli aspetti economici e ambientali
Il cambiamento climatico in atto ci spinge ad intervenire rapidamente con azioni efficaci e durature nel tempo. Tra i principali settori inquinanti, l'energia utilizzata negli edifici, nelle industrie e nei trasporti è causa della gran parte delle emissioni di gas serra a livello mondiale. L'elettrificazione di questi settori è una delle soluzioni ottimali per il processo di decarbonizzazione supportando le politiche della transizione energetica in corso.
La produzione di energia elettrica da fonti rinnovabili e la crescita esponenziale del mercato dei veicoli elettrici a livello mondiale sono la chiave per un futuro sostenibile. Tuttavia, nonostante il loro potenziale, portano l'attenzione sulla loro reciproca integrazione al fine di comprendere a fondo i reali vantaggi dal punto di vista energetico, economico ed ambientale. Inoltre, la possibilitĂ di scambio energetico bidirezionale grazie all'avvento della tecnologia Vehicle-to-Grid (V2G) definisce nuove opportunitĂ di integrazione e supporto alla rete elettrica.
In questo lavoro, vengono studiate la gestione energetica e il controllo ottimizzato per l'integrazione dei veicoli elettrici con la rete elettrica e i sistemi di generazione rinnovabile distribuita. Nella prima parte viene introdotto il problema delle emissioni, l'elettrificazione dei trasporti e le definizioni di alcuni concetti chiave. Successivamente, l'integrazione dei veicoli elettrici viene studiata da due diversi punti di vista. Il primo, in parte in collaborazione con la Christian-Albrechts-Universität (CAU) a Kiel, si focalizza su aspetti legati all'elettronica di potenza e al controllo di basso livello, mostrando un confronto tra diverse topologie di convertitori DC-DC (DAB), un'analisi sull'efficienza totale di ricarica del veicolo e la simulazione di un sistema V2G sperimentale per la fornitura di servizi ancillari.
Il secondo invece si concentra maggiormente sulla gestione ed il controllo predittivo dei flussi energetici per l'integrazione dei veicoli elettrici con microreti, focalizzando l'attenzione su aspetti economici ed ambientali. In particolare, viene mostrata l'implementazione e la validazione sperimentale di un sistema di controllo real-time per una stazione di ricarica fotovoltaica installata presso l'UniversitĂ di Trieste, un sistema V2G integrato all'interno di uno ski-resort Alpino ed infine, uno studio relativo ad una microrete condominiale che mostra i vantaggi legati ad un gruppo di autoconsumatori che agiscono collettivamente.Ongoing climate change is driving the need for rapid action with effective and long-term impacts. Among the major polluting sectors, energy used in buildings, industries, and transportation accounts for most of the world's greenhouse gas emissions. Electrification of these sectors is one of the optimal solutions for the decarbonization process by supporting the ongoing energy transition policies.
Electricity generation from renewable sources and the exponential growth of the global electric vehicle market are the key to a sustainable future. However, despite their potential, they bear attention to their mutual integration in order to fully understand the real benefits from energy, economic and environmental perspectives. In addition, the possibility of two-way energy exchange through the advent of Vehicle-to-Grid (V2G) technology defines new opportunities for integration and support to the power grid.
In the present work, optimized energy management and control for the integration of electric vehicles with the power grid and distributed renewable generation systems are studied. In the first part, the emission problem, electrification of transportation and definitions of some key concepts are introduced. Next, the integration of electric vehicles is studied from two different perspectives. The first, partially in collaboration with the Christian-Albrechts-Universität (CAU) in Kiel, focuses on aspects related to power electronics and low-level control, showing a comparison of different DC-DC converter (DAB) topologies, an analysis of total vehicle charging efficiency, and a simulation of an experimental V2G system for providing ancillary services.
The second focuses more on the management and predictive control of energy flows for the integration of electric vehicles with microgrids, focusing on economic and environmental aspects. In particular, it shows the implementation and experimental validations of a real-time control system for a photovoltaic charging station installed at the University of Trieste, an integrated V2G system within an Alpine ski-resort, and finally, a study related to a condominium microgrid showing the benefits related to a group of jointly acting renewables self-consumers
Analytical methods for series compensation of a transmission line
The paper proposes an analytical approach to evaluate the effects of series compensation of an overhead
transmission line (OHL) concerning the increase of (1) loadability and (2) practical loading of the line. The first
part of the paper focuses only on the line characteristics, and proposes an analytical approach to determine the
loadability curves of the line as a function of the compensating capacitive reactance. In the second part of the
paper, the perspective shifts to examine the power loading of the selected OHL in a meshed electrical network.
The target is to evaluate the compensation degree required to achieve a desired power flow increase in the line.
To this purpose a fast analytical method, based on the compensation theorem, is presented. Preserving the
linearity of the network model, the proposed method allows computation of the needed compensation degree by
means of a closed form equation. Numerical applications performed on two simple test networks allow to
compare the method with an ad hoc implemented classical optimal power flow. The results validate the method
and highlight its effectiveness as a simple and useful tool to support power system planners and designers
INTEGRAZIONE DELLA CHIMICA E DELLA BIOTECNOLOGIA PER LA VALORIZZAZIONE SOSTENIBILE DELLA BIOMASSA
This PhD work is part of a national project CARDIGAN (CARDoon valorisation by InteGrAted biorefinery), which was focused on the valorization of cardoons. a typical biomass of Mediterranean area. The first activity was the optimization of supercritical CO2 extraction (scCO2) applied on the cardoon leaves. Extracts (CLEs) were analysed by means of NMR and GC-MS to identify the most important bioactive molecules and to compare the composition of extracts obtained by different technologies by other partners in the project. The characterization indicated that scCO2 method extracts preferentially hydrophobic components whereas the Naviglio® technology allows to obtain extracts rich in cynaropicrin, a bioactive molecule with hepato-protectant activity. A first manuscript was published in collaboration with the Univ. of Naples and CNR-IPCB dealing with the formulation of bio-based polymeric films enriched with CLEs, which demonstrated increased the mechanical and barrier properties. The biological properties of CLEs were also investigated in collaboration with the neurobiology research group at the University of Trieste. The biological tests indicated that the CLE obtained by scCO2 from plants harvested in spring was able to induce a significant rescue of neuronal atrophy in an in vitro model of Rett syndrome neurons. RTT neurons whereas the more hydrophilic extracts, rich in cynaropicrin, exerted a toxic effect.
The second part of the project was focused on the valorization of cardoon seed oil to obtain epoxidized fatty acids as precursors in the synthesis of biolubricants and bioplasticizers. After the characterization of the cardoon seed oil, two lipases were used for its hydrolysis, up to 2L scale. The chemoenzymatic epoxidation was then carried out on oleic, linoleic and linolenic acids in solvent-less conditions at 50°C.
To improve the sustainability of the enzymatic process, the covalent immobilization of lipases on a renewable bio-composite material, rice husk, was investigated. The cellulosic fraction of rice husk was oxidized using laccase enzymes in the presence of TEMPO radical. The process leads to the oxidation of the primary hydroxyl groups of the glucose units of cellulose to aldehyde groups, which were exploited for the direct anchoring of the enzymes via formation of imine bonds with the superficial lysin residues of the proteins. These sustainable formulations were tested in various reaction media and under mechanical stress. The last part of this research was focused on the delignification of rice husk with the objective of improving its accessibility to oxidizing reagents and enzymes, while decreasing the hydrophobicity of this composite material.This PhD work is part of a national project CARDIGAN (CARDoon valorisation by InteGrAted biorefinery), which was focused on the valorization of cardoons. a typical biomass of Mediterranean area. The first activity was the optimization of supercritical CO2 extraction (scCO2) applied on the cardoon leaves. Extracts (CLEs) were analysed by means of NMR and GC-MS to identify the most important bioactive molecules and to compare the composition of extracts obtained by different technologies by other partners in the project. The characterization indicated that scCO2 method extracts preferentially hydrophobic components whereas the Naviglio® technology allows to obtain extracts rich in cynaropicrin, a bioactive molecule with hepato-protectant activity. A first manuscript was published in collaboration with the Univ. of Naples and CNR-IPCB dealing with the formulation of bio-based polymeric films enriched with CLEs, which demonstrated increased the mechanical and barrier properties. The biological properties of CLEs were also investigated in collaboration with the neurobiology research group at the University of Trieste. The biological tests indicated that the CLE obtained by scCO2 from plants harvested in spring was able to induce a significant rescue of neuronal atrophy in an in vitro model of Rett syndrome neurons. RTT neurons whereas the more hydrophilic extracts, rich in cynaropicrin, exerted a toxic effect.
The second part of the project was focused on the valorization of cardoon seed oil to obtain epoxidized fatty acids as precursors in the synthesis of biolubricants and bioplasticizers. After the characterization of the cardoon seed oil, two lipases were used for its hydrolysis, up to 2L scale. The chemoenzymatic epoxidation was then carried out on oleic, linoleic and linolenic acids in solvent-less conditions at 50°C.
To improve the sustainability of the enzymatic process, the covalent immobilization of lipases on a renewable bio-composite material, rice husk, was investigated. The cellulosic fraction of rice husk was oxidized using laccase enzymes in the presence of TEMPO radical. The process leads to the oxidation of the primary hydroxyl groups of the glucose units of cellulose to aldehyde groups, which were exploited for the direct anchoring of the enzymes via formation of imine bonds with the superficial lysin residues of the proteins. These sustainable formulations were tested in various reaction media and under mechanical stress. The last part of this research was focused on the delignification of rice husk with the objective of improving its accessibility to oxidizing reagents and enzymes, while decreasing the hydrophobicity of this composite material
Assessment of skin sensitization properties of few-layer graphene and graphene oxide through the Local Lymph Node Assay (OECD TG 442B)
: Skin contact is one of the most common exposure routes to graphene-based materials (GBMs) during their small-scale and industrial production or their use in technological applications. Nevertheless, toxic effects in humans by cutaneous exposure to GBMs remain largely unexplored, despite skin contact to other related materials has been associated with adverse effects. Hence, this in vivo study was carried out to evaluate the cutaneous effects of two GBMs, focusing on skin sensitization as a possible adverse outcome. Skin sensitization by few-layer graphene (FLG) and graphene oxide (GO) was evaluated following the Organization for Economic Cooperation and Development (OECD) guideline 442B (Local Lymph Node Assay; LLNA) measuring the proliferation of auricular lymph node cells during the induction phase of skin sensitization. Groups of four female CBA/JN mice (8-12Â weeks) were daily exposed to FLG or GO through the dorsal skin of each ear (0.4-40Â mg/mL, equal to 0.01-1.00Â mg/ear) for 3 consecutive days, and proliferation of auricular lymph node cells was evaluated 3Â days after the last treatment. During this period, no clinical signs of toxicity and no alterations in body weight and food or water consumptions were observed. In addition, no ear erythema or edema were recorded as signs of irritation or inflammation. Bromo-deoxyuridine (BrdU) incorporation in proliferating lymphocytes from ear lymph nodes (stimulation indexes <1.6) and the histological analysis of ear tissues excluded sensitizing or irritant properties of these materials, while myeloperoxidase activity in ear biopsies confirmed no inflammatory cells infiltrate. On the whole, this study indicates the absence of sensitization and irritant potential of FLG and GO
Terragni tra Como e Roma: modernità e città storica Como ve Roma Arasında Terragni: Modernizm ve Tarihi Şehir
Questo testo si propone di analizzare alcuni progetti di Giuseppe Terragni per Como e per Roma, in un periodo compreso tra il 1933 e il 1941. L’obiettivo è di evidenziare - seppure in un quadro di forte coerenza - i diversi modi seguiti dall’architetto nell’affrontare il tema del rapporto tra moderno e città storica
Climate Change and Building Renovation: Effects on Energy Consumption and Internal Comfort in a Social Housing Building in Northern Italy
Climate change is becoming a crucial factor to consider within human activities and the building sector is particularly influenced by aspects of internal comfort and energy. In Italy, great attention has been paid to the energy refurbishment of buildings. However, such interventions are mostly focused on reducing heating energy consumption, thus neglecting summer season performance. Moreover, climate change is barely considered during the design phase. This issue is addressed in this work which analyzes some of the most common refurbishment interventions applied to a social housing building in Trieste, while also considering internal comfort during the summer season. A dynamic analysis of the building-plant system is carried out using EnergyPlus. Fanger, UTCI and the adaptive comfort models were used to represent internal health, while three TRY data sets were generated using two GCM–RCM projections to evaluate the influence of climate change. The results show that both building insulation and climatic change affect heating consumption reaching a 70% reduction. However, building insulation does not greatly affect internal comfort, although different models show different behavior to protect against external temperatures. On the contrary, climatic change influences the percentage of hours of discomfort, with a 20% increase for all of the models. The final consideration is that people’s internal health should always be considered when carrying out refurbishment activities
Ferruginous bodies exert a strong proinflammatory effect
One of the main problems related to ferruginous-asbestos bodies (ABs) exposure is their potential pathogenetic role in asbestos-related diseases. The aim of this study was to examine whether purified ABs, might stimulate inflammatory cells. ABs were isolated by exploiting their magnetic properties, therefore avoiding the strong chemical treatment usually employed for this purpose. This latter treatment, which is based upon the digestion of organic matter with concentrated hypochlorite, may markedly modify the AB structure and consequently also their "in vivo" manifestations. ABs were found to induce secretion of human neutrophil granular component myeloperoxidase, as well as stimulate rat mast cell degranulation. Data demonstrated that by triggering secretory processes in inflammatory cells, purified ABs may play a role in the pathogenesis of asbestos-related diseases by continuing and enhancing the pro-inflammatory activity of the asbestos fibers
Do innovation and financial constraints affect the profit efficiency of European enterprises?
This paper investigates the relationship between profit efficiency, finance and innovation. By adopting stochastic frontiers, we pioneer the use of a novel dataset merging firm level survey data with balance sheet information for a large sample of
European companies. We find that firms having difficulties in access to finance as
well as firms introducing product innovation display an incentive to improve their
efficiency. While innovation produces benefit for firms’ profitability, financial constraints impose a discipline to the firms forcing them to cut unproductive costs that
reduce the profitability. We document nuanced differences between firms in industry
and services, while they are more pronounced when we look at disaggregation
across High-Tech and Low-Tech companies. From a policy perspective, our results
enrich the understanding on the link between innovation, financial constraints and
efficiency, which goes beyond the idea that easier access to finance is the panacea to
get higher performance
Analisi dei processi di innesco delle colate detritiche finalizzate allo studio delle dinamiche di propagazione
Il lavoro riguarda l’implementazione di una catena modellistica per l’analisi delle colate detritiche in grado di simulare sia l’evento critico di innesco di precipitazione, attraverso modelli idrologici di piena, che la successiva propagazione a valle del materiale già distaccato posto in alveo, attraverso la modellazione idrodinamica.
Gli aspetti di tale modellazione affrontati nella tesi riguardano: (i) la calibrazione e validazione di un modello idrologico in bacini montani, spesso caratterizzati da mancanza di misure o dati poco attendibili; (ii) la stima della portata solida a partire dalla portata liquida; (iii) la scelta di un modello reologico per la corretta caratterizzazione della miscela solido-liquida; (iv) l’implementazione di un modello di propagazione che tenga conto delle pendenze ripide tipiche degli alvei torrentizi e di un criterio di arresto.
La framework modellistica è costituita dal modello idrologico semi-distribuito GEOframe-NewAge, qui adottato per la prima volta ad una scala temporale di 5 minuti, adeguata a catturare gli eventi meteorici intensi che causano l’innesco; dal modello idrodinamico in-house DAM_DEBRIS, che integra le classiche equazioni alle basse, qui appositamente modificate per tener conto delle alte pendenze di cui sono caratterizzati i bacini montani. Inoltre, è stato implementato un opportuno criterio di arresto e sono state confrontate più leggi reologiche per la caratterizzazione della miscela.
L’area di studio analizzata è la parte montana del bacino del fiume Fella (Alpi Giulie), situato nella parte nord-est della regione Friuli Venezia Giulia. Quest’area, infatti, è altamente suscettibile a fenomeni di colate detritiche in virtù sia delle caratteristiche geomorfologiche che di quelle pluviometriche, con precipitazioni particolarmente abbondanti ed intense. I risultati della modellazione idrologica hanno dimostrato l’attendibilità degli idrogrammi simulati anche in sezioni non strumentate. Relativamente alla parte idrodinamica, primi test effettuati su prove di laboratorio hanno mostrato risultati incoraggianti nell’ottica di una sua applicazione al caso reale.
La disponibilità di un simile strumento modellistico, potrà permettere lo studio di possibili scenari futuri indotti, per esempio, dall’intensificarsi di eventi meteorici particolarmente estremi, fornendo un ulteriore strumento per una efficiente pianificazione territoriale.The work of this thesis aims at implementing a hydro-morphodynamic modelling framework for debris flow analysis capable of simulating both the precipitation triggering event, through the hydrological modelling, and the subsequent downstream propagation of debris flow, through the hydrodynamic modelling.
The aspects addressed in the thesis concern: (i) the calibration and validation of an hydrological model in mountain basins, often characterized by scarcity of measurements or unreliable data; (ii) the estimation of solid hydrograph from the liquid one; (iii) the choice of a rheological model to characterize the solid-liquid mixture; and (iv) the implementation of a propagation model, which takes into account the steep slopes typical of river beds, and a runout criterion.
The framework consists of the semi-distributed hydrologic model GEOframe-NewAge, here adopted for the first time at a 5-minute time-step, which is adequate to capture the intense precipitation events that trigger the debris flowing; the in-house hydrodynamic model DAM_DEBRIS, which integrates the classical shallow water equations, here modified to account for the steep slopes of mountains basins. In addition, an appropriate runout criterion was implemented, and multiple rheological laws were compared for the mixture characterization.
The study area is the mountainous side of the Fella River basin (across the Julian Alps), located in the northeastern part of the Friuli Venezia Giulia region. This area is highly susceptible to debris flow phenomena due to both geomorphologic and rainfall characteristics, characterized by abundant and intense precipitations. The results of the hydrological modelling demonstrated the reliability of the simulated hydrographs in ungauged areas. With regard to the hydrodynamic part, first numerical tests carried out on laboratory tests showed encouraging results with a view to its application to the real case.
The availability of such a modelling tool, may allow the study of possible future scenarios induced, for example, by the intensification of extreme weather events, providing an additional tool for an efficient territorial planning
Approcci innovativi per l'elettrofilatura di polisaccaridi nella preparazione di membrane nanostrutturate per il trattamento di ferite difficili
Nella presente tesi di dottorato, i vantaggi offerti da matrici elettrofilate (come l’architettura biomimetica, l’elevata porosità e l’area superficiale) sono stati combinati con la bioattività dei polisaccaridi, in particolare con quella dell’acido ialuronico (naturalmente presente nella matrice extracellulare) e di un chitosano modificato con gruppi lattosidici (CTL), studiato per le sue proprietà bioattive, tra cui l’attività antiinfiammatoria nel microambiente della ferita, e qui usato per la prima volta per l’elettrofilatura di nanofibre.
Le limitazioni correlate all’elettrofilatura dei polisaccaridi sono state superate grazie all’aggiunta di un polimero sintetico (l’ossido di polietilene, PEO) e di un surfattante (il Tween® 20), utilizzato per ridurre la tensione superficiale in modo da ottenere nanofibre sottili, prive di difetti e con un diametro paragonabile a quello delle fibre di collagene della matrice extracellulare (50-500 nm). In seguito, l’attenzione si è spostata verso il passaggio più critico della stabilizzazione in acqua, poiché i prodotti elettrofilati a base di polisaccaridi vanno incontro ad una rapida dissoluzione, impedendone l’utilizzo quali medicazioni per ferite croniche. Per tale ragione, diversi metodi di reticolazione già studiati in letteratura sono stati testati (come EDC/NHS, glutaraldeide, genipina o trattamento al calore), rivelandosi tuttavia tutti infruttuosi a causa della natura fortemente idrofilica dell’acido ialuronico e del CTL. Pertanto, nuovi agenti reticolanti mai impiegati nel campo dell’elettrofilatura sono stati studiati; tra questi, il carbonildiimidazolo (CDI) ha dato i migliori risultati in termini di stabilità in acqua e mantenimento della morfologia fibrosa. Inoltre, è stata dimostrata la sorprendente abilità dei prodotti elettrofilati di trattenere grandi quantità di fluidi favorendo al contempo la permeazione del vapore acqueo, tramite una comparazione con una medicazione già presente in commercio a base di chitosano (il Chitoderm®) e con membrane polisaccaridiche non elettrofilate.
Nonostante ciò, la matrice a base di soli polisaccaridi non possiede una resistenza meccanica e consistenza che ne consentano la maneggiabilità e l’applicazione su una ferita.
Per questo motivo, sono stati disegnati altri sistemi elettrofilati a base di polisaccaridi, sfruttando due diverse strategie: i) la deposizione strato per strato (anche detta coating) dei polisaccaridi su una matrice elettrofilata a base sintetica costituita da policaprolattone (PCL); ii) la produzione di una membrana elettrofilata a due strati, formata da uno strato meccanicamente stabile di PCL e uno strato bioattivo e a rilascio rapido a base di polisaccaridi.
Queste due tipologie di strutture sono state caratterizzate per la loro morfologia, per le cinetiche di rilascio dei polisaccaridi, la capacitĂ di assorbire fluidi e la permeabilitĂ al vapore acqueo. Hanno, inoltre, rivelato una buona biocompatibilitĂ e bioattivitĂ nei confronti di fibroblasti umani del derma, la cui capacitĂ di rigenerazione era incentivata dalla presenza delle membrane contenenti polisaccaridi.
In aggiunta, l’antibiotico rifampicina è stato addizionato allo strato di PCL, per conferire a queste medicazioni anche proprietà antibatteriche, senza però alterarne la biocompatibilità . Il rilascio di antibiotico così come l’attività antibatterica contro Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa ed Escherichia coli sono stati testati, mostrando una maggiore efficacia nei confronti degli Stafilococchi e di Pseudomonas aeruginosa.In this PhD thesis, the advantages of electrospun matrices (such as biomimetic architecture, high porosity, and surface area) have been combined with the bioactivity of polysaccharides, focusing on hyaluronic acid (naturally present in the extracellular matrix, or ECM) and on a lactose-derivative of chitosan (CTL), which has been studied for its bioactive properties, including the anti-inflammatory activity in the wound microenvironment, and which is used here for the first time for the preparation of electrospun nanofibers.
The limitations associated to polysaccharide electrospinning have been overcome by blending them with a synthetic polymer (polyethylene oxide, PEO) and using a surfactant (namely, Tween® 20) to reduce solution surface tension, thereby producing thin and defect-free nanofibers with a diameter in the range of collagen ECM fibers (50-500 nm). Attention then turned to the more critical step of stabilization in water as the rapid dissolution of the electrospun polysaccharides would hamper their use as wound dressings. For this purpose, various crosslinking methods already investigated in the literature have been tested (such as EDC/NHS, glutaraldehyde, genipin, or heat treatment), all of which being unsuccessful given the highly hydrophilic nature of both hyaluronic acid and CTL. Hence, previously untested crosslinkers in the electrospinning field have been explored, with carbonyldiimidazole (CDI) exhibiting the best results in terms of water stability and fibrous morphology maintenance. Moreover, the ability of the electrospun products to retain a surprisingly high quantity of fluids while favoring water-vapor permeation has been demonstrated, comparing them with a commercial chitosan dressing (Chitoderm®) and non-electrospun polysaccharidic membranes.
However, the polysaccharide-based matrix alone did not possess proper stability and consistency to be handled and applied to a wound.
For this reason, other polysaccharide-based electrospun systems have been designed, by exploiting two different strategies: i) the layer-by-layer deposition (here also referred to as “coating”) of polysaccharides on a synthetic-based electrospun matrix (namely, polycaprolactone, PCL); ii) the production of a two-layer electrospun membrane with a mechanically stable PCL layer and a bioactive and fast releasing polysaccharide counterpart.
The two types of constructs have been characterized in terms of morphology, polysaccharide release kinetics, swelling capacity, and water vapor transmission ability. They revealed good biocompatibility and bioactivity towards human dermal fibroblasts, which showed enhanced healing ability in the presence of polysaccharide-endowed mats.
In addition, the antibiotic rifampicin has been added to the PCL layer, to confer the wound dressings antibacterial properties without compromising their biocompatibility. The antibiotic release as well as its inhibitory and bactericidal activity towards Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli have been tested, with higher efficacy against Staphylococci and Pseudomonas aeruginosa
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