1,720,998 research outputs found
On the interplay between pressure and gravitational forces in coalescing filters
No full textThis paper provides insights into processes governing oil-mist filtration in coalescing fillers. In particular, it resolves an apparent inconsistency between different published studies regarding the occurrence (or not) of internal gravity-induced flows. As a result of this, it also clarifies whether in industrially-relevant scenarios such as those pertaining to vertical filter cartridges, non-homogeneous vertical saturation patterns are triggered by these internal flows or are just a result of different oil loading rates. To address these issues, we use Eulerian-Lagrangian CFD simulations, which properly account for the effects of turbulent diffusion of liquid aerosol particles, to replicate an experimental setup available in the literature. In order to interpret results data, we introduce a new dimensionless number, termed S-M, defined as the ratio between pressure gradient and gravitational forces, which provides a bulk characterization of the flow and allows to assess whether internal gravity-induced flows, in a given cartridge-oil system, should be expected or not. We show that S-M explains well the few experimental data available in the literature and identifies specific behaviors associated with limiting S-M values being either very large or close to 1
A multiphase multicomponent flow and transport model for liquid aerosol filtration in coalescing fibrous filters
No full textPore-scale CFD simulations of liquid aerosol filtration in coalescing fibrous filters are currently limited by severe computational constraints. In this paper, we present a new multiphase multicomponent framework for modeling such dynamic filtration process at the Darcy-scale. Moving from the pore- to the Darcy-scale allows for significant reduction in computational efforts with limited repercussion on the representation of the filter geometry. In our model, two phases coexist within the filter, namely the injected oil-mist and the coalesced oil phase. The oil-mist phase consists of a mixture of a gas phase and oil droplets of different sizes. The governing equations are the standard ones of Darcy flow and transport in porous media, where the filtration processes, such as droplet capture and drainage, are accounted for through ad hoc mass exchange terms, which are coherent with the Jump & Channel model by Kampa et al. (2014). The equations are strongly non-linear and are solved through the IMplicit Pressure Explicit Saturation (IMPES) algorithm. Cell-centered finite volumes are used for discretization in space. The model is validated by replicating experiments of oil-mist filtration available in the literature for both wettable and non-wettable media, as well as for combinations of media with different wettability. Simulations are then performed for a variety of operational conditions, demonstrating both the accuracy and robustness of our implementation
Atrophic Maxilla with Fibula Flap and Implant-Supported Prosthesis
No full textA 48-year-old man came to plastic surgery department because he suffered from extreme superior jaw atrophy. In order to restore both the vertical and sagittal bone loss, according to prosthetic criteria, a vascularized fibula flap was planned. Neither early nor late complications were detected at the donor site. Clinical and radiologic signs of osteointegration were found at all implant sites at the time of prosthetic loading. The success rate of loaded implants was 100%. Patient was both functionally and aesthetically satisfied with the results
Extended and unusual indications in jaw reconstruction with the fibula flap: An overview based on our 30-year experience
Full text linkSince the introduction of fibula flap as a reconstructive technique, an evolution of indications has been observed. Our first report of a traumatic mandibular reconstruction using fibula flap was in 1992. The vast majority of indications for surgery, are: malignant tumors, benign neoplasms, osteoradionecrosis and traumas. Nevertheless, extended indications have been described such as the treatment of dentoalveolar defect without bone discontinuity or reconstruction of maxilla defect up to type III (A and B), according to Cordeiro's classification. Unusual indications include cleft palate malformations with bone discontinuity less than 6 cm. Moreover, a particular attention should be focus on fibula flap harvest with more innovative technologies than traditional use of monopolar or bipolar and their advantages in pre and postoperative management
Factors related to delayed treatment: A case report of a huge cutaneous horn and review of the literature
Full text linkWe present a case of a man with a giant cutaneous horn over his frontal region. This case has been presented for the size of the lesion, due to delayed treatment, and to illustrate the reasons why the growth of this lesion has been possible in a western country, in the 21st century. It was a solitary, not painful lesion which caused significant aesthetic problems. The diagnosis was based on an ultrasonographic study and the treatment of choice was a surgical excision. This case is an opportunity to review the literature about the cutaneous horns, to talk about the main causes of delayed diagnosis and treatment of cutaneous lesions and, to define the role of the specialist in the assessment of emotions and patient support
Diagnosis and treatment of upper eyelid lipoma: A case report
Full text linkPurpose: Presentation of a rare lesion: a case of upper eyelid lipoma, Observations: A 76-year-old otherwise healthy woman presented with a right upper eyelid swelling. Her medical history was recorded. On ophthalmologic examination a soft, non-ulcerated and not well-circumscribed mass was evident. An ultrasonography examination was carried out showing a hyperechoic non capsulated mass situated between the superior orbital margin and the orbicularis oculi muscle. Conclusions and Importance: Eyelid lipomas must be differentiated from herniated orbital fat, cystic lesions, tumours, and the lacrimal gland. A pre-operative differential diagnosis of eyelid lipoma can be done through medical history, ophthalmologic, and ultrasonography examinations. Nevertheless, in case of doubt a magnetic resonance imaging (MRI) should be performed to assess a possible orbital involvement and to plan for the right surgical procedure to be performed
Median nerve injury caused by screw malpositioning in percutaneous scaphoid fracture fixation
Full text linkAn unusual complication of percutaneous fixation of a schapoid fracture in a 36-year-old man is described. After this surgery, the patient complained of numbness and tingling within the median nerve distribution and thenar weakness. An Electromyography showing moderate CTS had led to carpal tunnel decompression, which resulted unsuccessful. When the patient presented to us, both sensory and motor median nerve impairment were present, interfering with his professional activity. A computed tomography scan performed to assess the scaphoid screw position, showed that the screw had been placed volar to the scaphoid, adjacent to the median nerve. Surgery confirmed median nerve compression by the screw, especially during complete wrist extension. The surgical removal of the screw led to immediate improvement of both the motor and sensory functions of the nerve, with complete clinical restoration of nerve function and resolution of the symptoms 2 months postoperatively
Management of locked volar radio-ulnar joint dislocation
Full text linkIsolated volar dislocation of the distal radio-ulnar joint is an extremely rare lesion. Diagnosis is commonly missed. The authors report their experience about a case of an acute locked volar distal radio-ulnar joint dislocation. A correct clinical and radiological diagnosis was done in the Emergency Department, and a closed reduction was achieved only after an axillary block, after a first failed attempt under slight sedation. A K-wire blocking the prono-supination and a short removable forearm cast protected the reduction for 25 days. Two weeks after the removal of the immobilization, the patient presented a complete functional recovery, with full range of motion. The authors highlight the importance of the clinical and radiological findings: a dorsal dimple at the ulnar side leads to a high index of suspicion, and represent the most relevant aid in diagnosis, associated to a proper imaging assessment. Prompt management allows a minimally invasive approach and a rapid functional recovery
A Rare Case of Nipple-Areolar Complex Partial Necrosis following Micropigmentation: What to Learn?
Full text linkSummary: A 52-year-old woman, without any comorbidity, presented at our institution for reconstruction of nipple-areolar complex (NAC). Nipple reconstruction was obtained through local skin flaps. After 2 months, a tattoo of the NAC was performed. Follow-up was planned at 6 months. Nevertheless, the patient came to our attention 2 days after tattooing for partial necrosis of the epidermal-dermal layer of the tattooed area with partial muscular layer exposition. Empirical antibiotic treatment was immediately started to avoid infection. Daily medications were performed for 3 weeks. Complete healing was obtained within 3 weeks without the necessity of a skin graft. We think that the partial necrosis of the NAC occured because of vascular impairment of the dermal and subdermal vascular plexus during micropigmentation. From this experience, we developed some advice to improve our clinical practice by allowing surgeons, especially if trainees, to avoid complications in performing NAC micropigmentation
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