108 research outputs found

    The pyrolysis and gasification pathways of automotive shredder residue targeting the production of fuels and chemicals

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    Automotive shredder residue (ASR), also referred to as car fluff, is the 15-25% of end-of-life vehicle’s mass remaining after de-pollution, dismantling, shredding of the hulk and removal of metals from the shredded fraction. ASR typically consists of metals, plastics, rubber, textile, wood and glass, and is commonly landfilled. The use of ASR as a fuel in incineration processes is controversial since toxic pollutants can be generated as by-products if operational conditions and gas cleaning systems are not carefully controlled. Thermochemical treatment of ASR consists of advanced technology processes that convert ASR components liable to decomposition under the application of heat into liquids and/or gases and a solid residue containing metals. Within the thermochemical treatment options for ASR, pyrolysis and gasification are generally considered as the emerging technologies. The pyrolysis process uses medium temperatures (400-600°C) and an oxygen-free environment to decompose ASR chemically, thus producing minimum emissions and allowing metals to be recovered. Gasification is operated at higher temperatures (>700-800°C) and typically uses air as a gasification agent, which raises some issues in terms of emissions. Lab and pilot-scale plants fed with ASR have been built using both technologies, also considering a combination of them. The aim of this paper is the identification of the best conversion pathway for the production of transportation fuels, aviation fuels or chemicals (hydrogen, methanol, etc.) from ASR. The intermediate products from gasification and pyrolysis are used as feedstock in secondary processes for the production of the final products. The heterogeneous and complex composition of ASR raises several challenges upon its thermochemical treatment, so that the second step of the conversion process is typically not even addressed. Instead, this further step is fundamental to obtain some valuable products that can directly replace fossil derived fuels or chemicals. The updated picture presented in this work should help identify the main advantages and drawbacks of the pyrolysis and gasification processes when considered part of an overall ASR to fuels or chemicals plant

    Hybrid Turbo-Shaft Engine Digital Twinning for Autonomous Aircraft via AI and Synthetic Data Generation

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    Autonomous aircraft are the key enablers of future urban services, such as postal and transportation systems. Digital twins (DTs) are promising cutting-edge technologies that can transform the future transport ecosystem into an autonomous and resilient system. However, since DT is a data-driven solution based on AI, proper data management is essential in implementing DT as a service (DTaaS). One of the challenges in DT development is the availability of real-life data, particularly for training algorithms and verifying the functionality of DT. The current article focuses on data augmentation through synthetic data generation. This approach can facilitate the development of DT in case the developers do not have enough data to train the machine learning (ML) algorithm. The current twinning approach provides a prospective ideal state of the engine used for proactive monitoring of the engine’s health as an anomaly detection service. In line with the track of unmanned aircraft vehicles (UAVs) for urban air mobility in smart city applications, this paper focuses specifically on the common hybrid turbo-shaft in drones/helicopters. However, there is a significant gap in real-life similar synthetic data generation in the UAV domain literature. Therefore, rolling linear regression and Kalman filter algorithms were implemented on noise-added data, which simulate the data measured from the engine in a real-life operational life cycle. For both thermal and hybrid models, the corresponding DT model has shown high efficiency in noise filtration and a certain amount of predictions with a lower error rate on all engine parameters except the engine torque

    Optimization of micro single dielectric barrier discharge plasma actuator models based on experimental velocity and body force fields

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    Recently, the Micro Single Dielectric Barrier Discharge Plasma Actuator has become attractive for application in aeronautics and micropopulsion thrusters. The present work carried out a preliminary characterization of such device, acting on initially quiescent air by experimental and numerical approaches. Sinusoidal voltage excitation with amplitude up to 7 kV and frequency up to 2.5 kHz was applied. The induced flow was investigated by particle image velocimetry and the measured velocity fields were used to estimate experimentally the time-averaged induced body force distributions by a differential method. Plasma induced forces were modeled by following three different approaches, later implemented as a source term in the Navier-Stokes equations for the fluid flow simulations. Potentialities, advantages and disadvantages of the considered force modeling methods were investigated. Quantitative comparison of the experimental and numerical induced force, as well as of the velocity fields, allowed establishing which model best predicted the actuator effects. The algebraic Dual Potential Model provided a good agreement between experimental and simulated results, in terms of flow velocities and thickness of the induced wall-jet. The downstream decay of the wall-jet velocity, experimentally observed, was also successfully predicted. A maximum induced velocity of ≈2 m/s was obtained and a jet thickness of ≈3 mm

    Renal allograft compartment syndrome: is it possible to prevent?

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    Renal allograft compartment syndrome (RACS) is a complication characterized by increased pressure over 15 to 20 mm Hg of the iliac fossa site of transplanted kidney that can lead to a reduction of the blood supply to the graft, resulting in organ ischemia. This study aims to evaluate, through a review of the literature, the incidence, detection, treatment, and possible prevention of RACS. The incidence of this complication, which appears generally in the immediate post-transplantation period, is currently approximately 1% to 2% and is underestimated because of poor nosography for the presence of symptoms common to other post-transplantation complications. Doppler ultrasound is indispensable to evaluate the graft function in the immediate postoperative period and in the following days. The onset of RACS involves a surgical decompression of the graft and the subsequent closure of the abdominal wall with tension-free technique. Several authors agree that only the immediate surgical decompression following an early diagnosis can ensure a recovery of the graft. Early detection of the RACS is the key to preventing the loss of the graft. It is desirable to prevent this syndrome by reducing the discrepancy in weight between donor and recipient by 17%. However the shortage of organs makes such a selection not easy; therefore, in cases at risk for RACS, a close instrumental and clinical monitoring of the patient during post-transplantation recovery is recommended, so a prompt surgical decompression can be performed if RACS is suspected

    Electrospun Polyhydroxyethyl-Aspartamide-Polylactic Acid Scaffold for Biliary Duct Repair: A Preliminary In\ua0Vivo Evaluation

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    Tissue engineering has emerged as a new approach with the potential to overcome the limitations of traditional therapies. The objective of this study was to test whether our polymeric scaffold is able to resist the corrosive action of bile and to support a cell's infiltration and neoangiogenesis with the aim of using it as a biodegradable tissue substitute for serious bile duct injuries. In particular, a resorbable electrospun polyhydroxyethyl-aspartamide-polylactic acid (90 mol% PHEA, 10 mol% PLA)/polycaprolactone (50:50 w/w) plate scaffold was implanted into rabbit gallbladder to assess the in\ua0vivo effects of the lytic action of the bile on the scaffold structure and then as a tubular scaffold to create a biliary-digestive anastomosis as well. For the above evaluation, 5 animals were used and killed after 15 days and 5 animals after 3 months. At 15-day and 3-month follow-ups, the fibrillar structure was not digested by lytic action bile. The fibers of the scaffold were organized despite being in contact with bile action. A new epithelial tissue appeared on the scaffold surface suggesting the suitability of this scaffold for future studies of the repair of biliary tract injuries with the use of resorbable copolymer on biliary injuries

    Analisi dei fattori di rischio dell'ipoparatiroidismo transitorio e definitivo nei pazienti sottoposti a tiroidectomia

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    Obiettivi. Con questa revisione della letteratura ci proponiamo di valutare quali sono i fattori che possono essere valutati nei pazienti da sottoporre a tiroidectomia ai fini di una migliore gestione preoperatoria e post-operatoria dell\u2019ipoparatiroidismo transitorio e definitivo. Discussione. L\u2019ipoparatiroidismo transitorio \ue8 una complicanza potenzialmente grave che include una vasta gamma di segni e sintomi che permane solo per poche settimane dopo l\u2019intervento chirurgico. L\u2019ipoparatiroidismo definitivo si verifica quando \ue8 necessario un trattamento medico per un periodo maggiore di 12 mesi. I fattori di rischio che ne possono influenzare l\u2019insorgenza in seguito ad interventi di tiroidectomia sono molteplici: biochimici preoperatori e post opera- tori, il sesso femminile, la malattia di Graves e le malattie neoplastiche della tiroide, l\u2019abilit\ue0 del chirurgo e la tecnica chirurgica utilizzata. Il trattamento medico prevede la somministrazione di calcio, vitamina D e talvolta magnesio. Conclusioni: Anche se i fattori biologici e biochimici legati al paziente ricoprono una certa importanza nella correlazione con l\u2019ipoparatiroidismo, riteniamo che i fattori causali pi\uf9 importanti sono da correlare alle variabili intraoperatorie come l\u2019esperienza del chirurgo e la tecnica utilizzata che deve mirare alla visualizzazione e al rispetto in situ delle paratiroidi.Aims. This review evaluates those main risk factors that can affect patients undergoing thyroidectomy, to reach a better pre- and post-operative management of transient and permanent hypoparathyroidism. Discussion. The transient hypoparathyroidism is a potentially severe complication of thyroidectomy, including a wide range of signs and symptoms that persists for a few weeks. The definitive hypoparathyroidism occurs when a medical treatment is necessary over 12 months. Risk factors that may influence the onset of this condition after thyroidectomy include: pre- and post-operative biochemical factors, such as serum calcium levels, vitamin D blood concentrations and intact PTH. Other involved factors could be summarized as follow: female sex, Graves' or thyroid neoplastic diseases, surgeon's dexterity and surgical technique. The medical treatment includes the administration of calcium, vitamin D and magnesium sometimes. Conclusions. Although biological and biochemical factors could be related to iatrogenic hypoparathyroidism, the surgeon's experience and the used surgical technique still maintain a crucial role in the aetiology of this important complication

    A SIMPLE TECHINIQUE TO IMPROVE RESIDUAL SKIN PLASTICITY FOR SCROTAL RECONSTRUCTION IN FOURNIER'S GANGRENE

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    A 50 years-old man developed 24 hours after hemorroidectomy a severe Fournier's gangrene of the scrotum necessitating surgical exeresis of more than 2/3 of scrotal skin followed by hyperbaric oxygen therapy. After the resolution of the septic phase, scrotum reconstruction was obtained by tissue expansion to avoid more invasive advanced reconstructive techniques. The procedure consisted of an enzymatic and mechanical debridement and progressive skin expansion by package of gauzes of increasing volume covered with a collagenase-cloramphenicol ointment (Iruxol - Smith & Nephew, Italy), then closing the wound edges by temporary stitches to put under tension the skin. The reestablishement of the natural elasticity of the scrotal skin was obtained in ten days and at the final closure of the wound edges an acceptable optimal aesthtic result was achieved

    THE MANAGEMENT OF POSTOPERATIVE PAIN AFTER HEMORRHOIDECTOMY: ANALYSIS OF THREE METHODICS

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    Postoperative pain is one of the most common and disabling complications following hemorrhoidectomy. This study divided a total of 90 patients, undergone Milligan and Morgan hemorrhoidectomy, in three groups of 30 patient: Group A, undergone internal sphincterotomy after hemorrhoidectomy; Group B, treated with Diosmin 500 mg; Group C, treated with Paracetamol 1000 mg when required. The analysis of the median VAS score (Visual Analogic Scale) of postoperative pain, in every group pointed out a relationship between postoperative pain reduction and time at the three set checkpoints (1st, 3rd, 9th postoperative day) (R2= 0.9231 for Group A; R2= 0.9423 for group B; R2= 0.9423 for group C). Mean VAS scores have been worked out for the three checkpoints and we compared the results between the three groups. Conclusions: in our study, internal sphincterotomy was the only therapeutic choice able to reduce most of the others the postoperative pain, both the 1st, the 3rd and the 9th postoperative day

    MANAGEMENT OF LEIOMYOMA OF THE TRANSVERSE COLON: CASE REPORT

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    Colonic leiomyoma is a mesenchymal tumor that arises from the muscularis mucosae or muscularis propria and is composed of well-differentiated smooth muscle cells with no atypia. It is often incidentally found since its growth affects the submucosal layer and the lesion is covered with normal epithelium. Endoscopic ultrasonography is recommended to define the grade of infiltration of the tumor and eventually lymph node involvement. Histological examination is critical to establish the nature of the tumor and its behaviour. In the case of a voluminous tumor surgical treatment is needed. we report case of a patient that underwent colonoscopy showing the presence of a neoformation at 70 cm from ileocecal valve occupying half lumen of transverse colon. A surgical resection was performed and histological analysis confirmed the presence of a leiomyoma

    THE NUCK'S CYST: A DISEASE EASILY CONFUSED FOR INGUINAL HERNIA. A CASE REPORT.

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    Nuck's canal cyst is a blind end adult residual of the fetal peritoneum. These rare cyst formations are usually found in the inguinal canal and can easily be mistaken for hernia, or enlarged limph nodes. Clinically, a Nuck's canal cyst appears as a painless or moderately painful swelling in inguinal area. We report the case of a 40 years-old woman with a painless swelling in her left inguinal region, believed a groin hernia but diagnosed as a Nuck's canal cyst only after intervention. Intraoperatively, the cyst was opened and sebsequently excised, closing the abdominal wall without the use of any sort of syntetic prostetic material
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