78 research outputs found
SUITABLE PATHWAYS FOR THE CO2 RE-USE IN OFFSHORE CONTEXTS: AN ORIENTED OVERVIEW OF APPLICABLE TECHNOLOGIES AND POTENTIAL OPPORTUNITIES
No full textThe paper explores technologies for the chemical and biological conversion of CO2 in offshore environments, highlighting the benefits and challenges of each. The chemical conversion of offshore CO2 requires promising technologies that are suitable for small installations, lighter systems and intensified unit operations. With regard to bio-inspired pathways, the paper examines microbiological, and biomolecular systems suitable for CO2 capture and use, exploiting the water abundance and space of the marine environment. Both scouting and classification activities were carried out in collaboration with primary academic institutions and research teams
Quantitative Risk Assessment of CO2 & H2 Offshore Pipelines-Advancing On Modelling Subsea Accidental Releases
No full textThe assessment of risks for human health and environment is a crucial step of the design of subsea pipeline systems. Well-recognized standards, such as DNV-RP-F107, recommend carrying out periodic risk assessment throughout the whole life cycle of a subsea pipeline system. The purpose of this paper is to present the upgrade of a lean and proprietary tool to assess the consequences of CO2 and H2 releases from subsea pipelines whenever a Quantitative Risk Assessment (QRA) is required. To quantify the risk for people and the environment involved in an accidental loss of containment of CO2 or H2 sealines, the physical effects of subsea releases need to be evaluated. The mathematical model described in this paper is based on state-of-the-art integral models developed for subsea releases. It models subsea plumes or subsea gas blowout considering the effects of sea current, sea salinity, sea temperature as well as the effects of impurities in the released stream. The model was validated through a comparison with a detailed Computational Fluid Dynamic (CFD) simulation and case studies available in literature. At present, the assessment of subsea CO2 and H2 releases, for QRA purposes, is performed either by very simplified and not validated approaches, which can lead to an overestimation of the consequences, or by complex CFD tools which require specific skills, high computational costs, and long duration of analysis often not in compliance with tight project schedules. The results of this paper show a sufficient level of accuracy of the in-house integral model with respect to other well-recognized integral models in the estimation of underwater plume behaviour, bubble zone extension at the sea surface, void fraction, and mean plume speed. Therefore, it can provide a suitable set of input data for simulation of atmospheric dispersion of CO2 and H2. The comparison of the results, carried out by means of a CFD tool on a set of case studies, shows a good agreement of the main predictive parameters. The model described is a suitable tool for consequences assessment in QRA studies for CO2 and H2 offshore pipeline projects concurring at the Net Zero objective, contributing to understand release impacts on safety and environment
A Monte Carlo simulation study of associated liquid crystals
No full textWe have performed a Monte Carlo simulation study of a system of ellipsoidal particles with donor ± acceptor sites modelling complementary hydrogen-bonding groups in real molecules. We have considered elongated Gay ± Berne particles with terminal interaction sites allowing particles to associate and form dimers. The changes in the phase transitions and in the molecular organization and the interplay between orientational ordering and dimer formation are discussed. Particle ¯ ip and dimer moves have been used to increase the convergency rate of the Monte Carlo (MC) Markov chain. 1
Clinical outcomes of single-stage versus two-stage laparoscopic Roux-en-y gastric bypass in the management of obesity (BMI ≥ 50 kg/m(2)): a retrospective cohort study
No full textBACKGROUND: Laparoscopic Roux-en-Y gastric bypass (LRYGB) in patients with obesity, BMI ≥ 50 kg/m(2), can be a challenging operation. Weight loss with intra-gastric balloon (IGB) insertion prior to LRYGB may improve operative outcomes. METHODS: Between June 2000 and June 2020, patients with a BMI ≥ 50 kg/m(2) underwent either IGB insertion followed by LRYGB (two-stage group), or LRYGB as the definitive bariatric procedure (single-stage group) in our institution. The two-stage procedure was adopted for high risk individuals. Primary outcome measures were percentage total weight loss (%TWL) at 24 months, length of stay and postoperative morbidity. Propensity score analysis was used to account for differences between groups. RESULTS: A total of 155 (mean age 42.9 years ± 10.60; mean BMI 54.6 kg/m(2) ± 4.53) underwent either the two-stage (n = 30) or single-stage procedure (n = 125) depending on preoperative fitness. At 6 months following LRYGB, there was a significant difference in %TWL between the groups in a matched analysis (11.9% vs 23.7%, p < 0.001). At 24 months, there was no difference in %TWL (32.0% vs 34.7%, p = 0.13). Median hospital stay following LRYGB was 2.0 (1-4) days with the two-stage vs 2.0 (0-14) days for the single-stage approach (p = 0.75). There was also no significant difference in complication rates (p = 0.058) between the two groups. CONCLUSIONS: There was no difference in weight loss after one or two-stage procedures in the treatment of patients with a BMI ≥ 50 kg/m(2 )super obesity in a propensity score weighted analysis at 24 months. Length of stay and perioperative complications were similar for high risk patients; however, the two-stage approach was associated with delayed weight loss. Single-stage management is recommended for moderate risk patients, particularly with significant metabolic disorders, whilst two-stage approach is a safe and feasible pathway for high risk individuals. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00423-022-02664-9
Il rischio di tensocorrosione da H2S all’esterno di condotte sottomarine: una metodologia di valutazione quantitativa
No full textUna sempre crescente attenzione è rivolta allo sviluppo di nuovi materiali da impiegare per la realizzazionedi condotte sottomarine da posare in acque molto profonde. In tali ambienti si possono presentare condizionianossiche in cui è favorita la proliferazione di batteri anaerobici, quali i solfato riduttori, che generanosignificative quantità di H2S che si accumula nei sedimenti di fondo. Tali condizioni, che potrebberopregiudicare l’integrità della condotta, si possono peraltro verificare anche in bacini chiusi,non necessariamente profondi. È noto che l’acciaio al carbonio comunemente utilizzato nelle condotte a mareè suscettibile a fenomeni di tensocorrosione da H2S umido, e tale problematica è potenzialmente riscontrabileladdove parti metalliche incidentalmente non coperte dai rivestimenti protettivi si trovino a contattoo in prossimità di sedimenti ricchi di H2S. Obbiettivo del presente articolo è proporre una metodologiache sia di supporto, in fase di progettazione, per la quantifica del rischio di tensocorrosione da H2Se che consideri, in termini probabilistici, i parametri ambientali, le condizioni di posa ed il materialedella condotta, in coerenza alle normative tecniche che ad oggi inquadrano lo stato dell’arte per le condottesottomarine e per i materiali da utilizzarsi in ambienti sour
Medicolegal Cases in Bariatric Surgery in the United Kingdom
No full textPURPOSE OF REVIEW: To evaluate the current state of bariatric medicolegal activity and explore the reasons of litigation in bariatric surgery. The underlying legal principles in bariatric medicolegal cases and most frequent pitfalls will also be discussed. RECENT FINDINGS: There is a growing number of litigations in bariatric surgery, particularly relating to complications and long waiting lists for bariatric surgery within the public-funded health systems. The main issues are related to consent, lack of follow-up, delayed identification of complications and lack of appropriate emergency management of complications, involving bariatric surgeons, clinicians, general practitioners and multidisciplinary team members. Appropriate multidisciplinary involvement pre- and postoperatively and robust follow-up protocols can help to mitigate the risks. Bariatric surgery requires a unique paradigm with a multidisciplinary approach both pre- and postoperatively to improve the long-term functional outcomes of patients. There is a rising incidence of medicolegal claims following bariatric surgery. The underlying reasons for this are multifactorial including an increase in the volume of surgery, high patient expectations, the incidence of long-term postoperative complications and the requirement of long-term follow-up
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