1,721,822 research outputs found
Comparison of proton and electron radiation effects on dark count rate in a CMOS SPAD sensor
No full textThe aim of this work is to investigate the degradation induced by radiation on the Dark Count Rate in a monolithic SPADs detector manufactured in a 150-nm CMOS process. Two irradiation campaigns have been carried out with 16 MeV protons and 2 MeV electrons. Samples have been exposed to different displacement damage dose. Differences between the effects induced by the two irradiation particle types have been observed. The Dark Count Rate characterization as a function of the delivered fluence has been reported, providing the limits of operability of such devices in a radiation environment. Finally, possible Dark Count Rate mitigation techniques have been investigated
Recent progress and challenges in biotechnological valorization of lignocellulosic materials: Towards sustainable biofuels and platform chemicals synthesis
No full textLignocellulosic materials (LCM) have garnered attention as feedstocks for second-generation biofuels and platform chemicals. With an estimated annual production of nearly 200 billion tons, LCM represent an abundant source of clean, renewable, and sustainable carbon that can be funneled to numerous biofuels and platform chemicals by sustainable microbial bioprocessing. However, the low bioavailability of LCM due to the recalcitrant nature of plant cell components, the complexity and compositional heterogeneity of LCM monomers, and the limited metabolic flexibility of wild-type product-forming microorganisms to simultaneously utilize various LCM monomers are major roadblocks. Several innovative strategies have been proposed recently to counter these issues and expedite the widespread commercialization of biorefineries using LCM as feedstocks. Herein, we critically summarize the recent advances in the biological valorization of LCM to value-added products. The review focuses on the progress achieved in the development of strategies that boost efficiency indicators such as yield and selectivity, minimize carbon losses via integrated biorefinery concepts, facilitate carbon co-metabolism and carbon-flux redirection towards targeted products using recently engineered microorganisms, and address specific product-related challenges, to provide perspectives on future research needs and developments. The strategies and views presented here could guide future studies in developing feasible and economically sustainable LCM-based biorefineries as a crucial node in achieving carbon neutrality
Characterization of the Radiation-Induced Damage in a PEN (Polyethylene Naphthalate) Scintillation Detector †
No full textThe radiation hardness of a Polyethylene Naphthalate (PEN) thin film scintillator has been characterized in terms of the light yield loss after irradiation with 11 MeV protons and 1 MeV electrons. The light yield distributions induced by excitation with radioactive sources have been measured on samples irradiated with different doses and the induced light loss has been computed. Results showed the good radiation hardness behaviors of PEN scintillators, with a light yield loss of ~15% at 10 Mrad and ~35% at the maximum delivered dose of 80 Mrad
Simultaneous denitrification, phosphorus recovery and low sulfate production in a recirculated pyrite-packed biofilter (RPPB)
No full textThe simultaneous removal of nitrate (15 mg N-NO3- L−1) and phosphate (12 mg P-PO43- L−1) from nutrient-polluted synthetic water was investigated in a recirculated pyrite-packed biofilter (RPPB) under hydraulic retention time (HRT) ranging from 2 to 11 h. HRT values ≥ 8 h resulted in nitrate and phosphate average removal efficiency (RE) higher than 90% and 70%, respectively. Decrease of HRT to 2 h significantly reduced the RE of both nitrogen and phosphorus. The RPPB showed high resiliency as reactor performance recovered immediately after HRT increase to 5 h. Solid-phase characterization of pyrite granules and backwashing material collected from the RPPB at the end of the study revealed that iron-phosphate, -hydroxide and -sulfate precipitated in the bioreactor. Thermodynamic modeling predicted the formation of S0 during the study. Residence time distribution tests showed semi-complete mixing hydrodynamic flow conditions in the RPPB. The RPPB can be considered an elegant and low-cost technology coupling biological nitrogen removal to the recovery of phosphorus, iron and sulfur via chemical precipitation
Radiation induced degradation in a 150-nm CMOS SPADs device
No full textThe effects induced by radiation on an innovative photo-sensor consisting of Single-Photon Avalanche Diodes arrays, implemented in a 150-nm CMOS technology, are presented. Samples were irradiated with a proton beam at different doses, and the impact of radiation-induced damage on the performance of the devices in terms of Dark Count Rate has been estimated. Furthermore, possible methods to reduce the impact of radiation-induced damage are discussed
Simultaneous nitrification–denitrification in biofilm systems for wastewater treatment: Key factors, potential routes, and engineered applications
No full textSimultaneous nitrification-denitrification (SND) is an advantageous bioprocess that allows the complete removal of ammonia nitrogen through sequential redox reactions leading to nitrogen gas production. SND can govern nitrogen removal in single-stage biofilm systems, such as the moving bed biofilm reactor and aerobic granular sludge system, as oxygen gradients allow the development of multilayered biofilms including nitrifying and denitrifying bacteria. Environmental and operational conditions can strongly influence SND performance, biofilm development and biochemical pathways. Recent advances have outlined the possibility to reduce the carbon and energy consumption of the process via the "shortcut pathway", and simultaneously remove both N and phosphorus under specific operational conditions, opening new possibilities for wastewater treatment. This work critically reviews the factors influencing SND and its application in biofilm systems from laboratory to full scale. Operational strategies to enhance SND efficiency and hints to reduce nitrous oxide emission and operational costs are provided
TECNOLOGIE E TRATTAMENTI PER LA MINIMIZZAZIONE DEI FANGHI DI DEPURAZIONE
No full textI fanghi costituiscono, come è noto, l’inevitabile prodotto di risulta dei processi attuati lungo la linea acque del ciclo di trattamento degli impianti di depurazione delle acque reflue. I dati più recentemente pubblicati dall’Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA) indicano, in Italia, una produzione di fanghi nel 2015 di oltre 3 milioni di tonnellate, destinata ulteriormente ad aumentare via via che andrà crescendo la percentuale di reflui avviati alla depurazione, ma anche in conseguenza del progressivo restringimento degli standard di qualità degli effluenti trattati, imposti dai provvedimenti normativi in materia.
Ovviamente, la suddetta cospicua produzione di fanghi comporta sia elevati costi dei relativi trattamento e smaltimento, che talvolta possono addirittura raggiungere il 50% di quelli necessari per la gestione complessiva degli impianti di depurazione (Andreoli et al., 2007), ma anche difficoltà sempre crescenti nell’individuare soluzioni per il loro smaltimento finale.
In tali condizioni, destano estremo interesse le soluzioni tecniche e tecnologiche volte alla riduzione della produzione di fango ma anche al miglioramento della sua qualità, al fine di facilitarne lo smaltimento o, ancora meglio, consentire il recupero dell’energia e della materia ad esso associate.
Nel seguito si riporta una sintetica illustrazione delle principali soluzioni che possono essere all’uopo adottate, prestando particolare attenzione agli interventi riguardanti il fango biologico, che, tipicamente, rappresenta l’aliquota preponderante
Enhancement and mechanisms of micron-pyrite driven autotrophic denitrification with different pretreatments for treating organic-limited waters
No full textPyrite-driven autotrophic denitrification (PAD) represents a cheap and promising way for nitrogen removal from organic-limited wastewater, which has obtained increasing attention in recent years. However, the limited denitrification rate and unclear mechanism underlying the process have hindered the engineered application of PAD. This study aims to shed light on the impacts of different pretreatments (i.e., ultrasonication, acid-washing and calcination) on micron-pyrite surface characteristics, denitrification performance and biofilm formation during PAD in batch reactors. A series of solid-phase analyses revealed that all pretreatments could significantly promote biofilm attachment on pyrite granules, but impacted the proportion, distribution and chemical oxidation state of sulfur (S) and iron (Fe) at varying degrees. Batch tests showed that ultrasonication and acid-washing could enhance the total nitrogen reduction rate by 14% and 99%, and decrease the sulfate production rate by 51% and 42%, respectively, when compared with untreated pyrite. Microbial community analysis indicated that Thiobacillus and Rhodanobacter dominated in PAD systems. Two types of indirect mechanisms (i.e., contact and non-contact) for pyrite leaching may co-occur in PAD system, resulting in ferrous iron (Fe2+), thiosulfate (S2O32-) and sulfide (S2-) as the main electron donors for denitrification. A PAD mechanism model was proposed to describe the PAD electron transfer pathway with the aim to optimize the engineered application of PAD for nitrogen removal
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