8,263 research outputs found
Basic Economic Analysis for Sonochemical Processes
No full textUltrasound (US) and other non-traditional energy sources (for instance microwave (MW)) are widely used to increase the rate of chemical reactions, to prepare nanoparticles, to extract natural products etc. In all such cases, the scaling-up of the process must have a defined economic constraint, which generally can be reduced to the evaluation of the parameter RC, which is the ratio between the raw energy cost to produce US (or MW) and the total production cost for unit mass of product. The paper gives a basic correlation among the different parameters to evaluate RC both for processes using only US (or MW and other not traditional sources) and those with mixed energy sources
Process intensification using energy-free highly enriched air: Application to seawater desalination plants
No full textA new process layout to intensify and make more sustainable chemical processes that use open-loop cooling/heating systems is broached. This new process demonstrates the possibility to recover a stream of highly-enriched air without any additional operational cost, but simply exploiting differently the existing energy sources. Enriched air can therefore be used to reduce the variable costs of the intensified plants as well as to reduce the volume of process facilities dedicated to steam generation or to directly increase the net operating margin as additional product (industrial or medical gas). General and dedicated process simulations combined with experimental evidence demonstrate the feasibility and the effectiveness of the proposed intensification. The application to the multi-effect distillation technology for seawater desalination is describe
Erratum: OncoScore: a novel, Internet-based tool to assess the oncogenic potential of genes
No full textScientific Reports 7: Article number: 46290; published online: 07 April 2017; updated: 22 May 2017 The original version of this Article incorrectly listed all author names in reverse. The author list now reads: Rocco Piazza, Daniele Ramazzotti, Roberta Spinelli, Alessandra Pirola, Luca De Sano, Pierangelo Ferrari, Vera Magistroni, Nicoletta Cordani, Nitesh Sharma & Carlo Gambacorti-Passerini.</jats:p
Liquid Levothyroxine Formulation Taken during Lunch in Italy: A Case Report and Review of the Literature
No full textLevothyroxine (L-T4) is among the most widely prescribed medications in the world, and it is considered by the World Health Organization an essential medicine for basic health care. Replacement therapy has always been considered straightforward although different factors may interfere with intestinal absorption of L-T4, including food, dietary fibre, coffee, drugs, and gastrointestinal diseases. For these reasons, current guidelines recommend that L-T4 should be taken in a fasting state because its absorption is maximised when it is taken on an empty stomach, reflecting the importance of gastric acidity in the absorption process. In addition to sodium L-T4 in tablet form, various formulations (soft-gel capsules and liquid solutions) have become available for clinical use in the last years promising improved absorption. We described a 31-year-old Italian man who took liquid levothyroxine formulation during lunch. He was under replacement therapy with liquid levothyroxine 75 mcg daily for hypothyroidism due to Hashimoto thyroiditis for three years. During confirmation of the L-T4 replacement therapy, the patient stated that he was going to continue to “take liquid levothyroxine during (his) lunch every day.” We recommended taking the medication correctly in the morning at least thirty minutes before breakfast and repeating TSH, fT4, and fT3 after three months. The thyroid hormonal profiles taken after 3 and 6 months were comparable to those when the patient was taking the medication during lunch. In conclusion, liquid levothyroxine formulation should be preferred in case of malabsorption or potential malabsorption. Liquid formulation should be preferred due to the possibility of taking it during breakfast, which significantly improves the compliance of patients. Further studies are needed to evaluate the possibility of taking liquid L-T4 during lunch
Selective synthesis of polyamines in multipurpose plants
No full textA number of reaction processes undergo yield drops since an intermediate target species can further react with one of the reactants generating lower volatility by-products. Such reactions are typically fast and non-selective, so that a gradual conversion of the reactants is recommended because of safety and quality constraints; when dealing with relatively low-volumes of a highly fragmented set of products, a semibatch reactor is normally adopted where the reaction selectivity is increased by increasing the excess of the selective reactant, therefore lowering the plant productivity. For increasing the process selectivity without reducing the plant productivity a different reactor configuration has been recently proposed: the so-called semibatch recycle reactor. However, the good performance of this configuration has never been experimentally confirmed. In this work, the unselective industrial synthesis of polyamines through alkylation of 1,2-dichloroethane with a diamine has been experimentally investigated both in a standard semibatch reactor as well as in a semibatch recycle reactor, showing that the latter can lead to a significant increase of both the process selectivity and productivity
Active Learning in Distance Education of Crude Distillation Unit by Virtual Immersive Laboratory : the Eye4edu Project
No full textThe use of virtual immersive laboratories is an appealing and synergistic possibility for education in science,
technology and engineering, complementary to experimental activities performed in laboratory or exercises
delivered in traditional rooms.
A new educational project, called Eye4edu, proposed different exercises on a virtual immersive Crude
Distillation Unit (VCDU), with the aim to apply an active scenario for the learning of the structure of the single
unit operations, the whole plant and the control and intervention operating procedures. The project was
proposed to the bachelor and master students for the degree in Industrial Chemistry in the Milan University in
the years 2019 and 2020. VCDU is based on the combination of the action of “Aveva XR for Training”,
formerly Eyesim, and Dynsim software, from Aveva Company, for the physical representation and the dynamic
chemical behaviour of the plant.
Several exercises on the plant were proposed to the students both for practical and management operations
in the plant. The students were required to work on the basis of the information available in the technical
documents, as PFD and P&ID. The project was proposed both in presence and as distance learning,
respectively before and during the health emergency due to SARS-CoV-2 pandemic. The description of the
virtual laboratory and an analysis of its use and educational impact in face-to-face and remote delivery is
reported in this paper
Comparison between experimental and simulated data of a distillation column: evaluation of mass-heat balances and trays efficiency
No full textA laboratory experience concerning a continuous distillation column for Industrial Chemistry and Chemical Engineering students is presented. The experience is based on practical exercise of the column running at infinite and finite reflux and on the elaboration of the collected data by both classical equations and computer simulation. The comparison between experimental and simulated data will help students to understand the theoretical basis of the distillation columns and the importance of a right representation of the phase equilibria representation. The mixture used as example in this work is a binary one of toluene and N-heptane
When self-consistency makes a difference
No full textCompound semiconductor power RF and microwave device modeling requires, in many cases, the use of selfconsistent electrothermal equivalent circuits. The slow thermal dynamics and the thermal nonlinearity should be accurately included in the model; otherwise, some response features subtly related to the detailed frequency behavior of the slow thermal dynamics would be inaccurately reproduced or completely distorted. In this contribution we show two examples, concerning current collapse in HBTs and modeling of IMPs in GaN HEMTs. Accurate thermal modeling is proved to be be made compatible with circuit-oriented CAD tools through a proper choice of system-level approximations; in the discussion we exploit a Wiener approach, but of course the strategy should be tailored to the specific problem under consideratio
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