Flow and heat transfer of Al2O3 and γ-Al2O3 through a channel with non-parallel walls: a numerical study.

Nanofluids are referred to as nanometer suspensions in standard nanometer-sized fluid transfer. In this study, our focus was to examine the flow and transmission of heat through a non-parallel walled channel of nanofluids. For this purpose, we used the thermal transport in H2O composed of Al2O3 and γ-Al2O3 nanomaterials within the convergent/divergent channel for stretching/shrinking parameters. The flow was considered two-dimensional and unsteady. As a result, the flow of an unstable fluid, including various nanoparticles, was modeled within the convergent/divergent channel. A suitable similarity transformation was used to convert the complicated coupled system of differential equations into a non-dimensional form. For numerical solutions, the complicated system of equations was first transformed into a set of first-order differential equations using the shooting method. The Runge-Kutta (RK-4) method was then used to solve the reduced first-order equations. To comprehend the flow pattern and temperature and velocity profile deviations caused by dimensionless parameters, a graphical investigation was performed. Graphs were also used to investigate the variation in the velocity and temperature profiles for various emerging factors.

[Risk factors for hospital mortality during pulmonary embolism]. / Facteurs de risque de mortalité hospitalière au cours de l'embolie pulmonaire en milieu de pneumologie.

OBJECTIVES: The objective of our work is to identify the risk factors for hospital mortality during pulmonary embolism in a pneumology department. MATERIAL AND METHOD: All patients admitted to the pneumology department of Habib-Bourguiba hospital between 2014 and 2019, with a final diagnosis of PE are analyzed. RESULTS: One hundred patients were included, 62% of whom were female, with an average age of 63±16 years. Pulmonary fibrosis was noted in eight patients. On admission, the mean Simplified Pulmonary Embolism Severity Index score was 1.46±1.05. The mean duration of hospitalization was 10.6±7 days. The hospital mortality rate was 12%. The independent risk factors for intra-hospital mortality were arterial hypotension (OR: 6.13; 95%CI: 2.88-14.35; p=0.001), cancer (OR: 2.66; 95%CI: 1.22-9.54; p=0.026), a VD/LV ratio at echocardiography>0.9 (OR: 1.84; 95%CI: 1.06-7.69; p=0.039) and severe hypoxemia (OR: 4.86; 95%CI: 2.19-11,34; p=0.006). CONCLUSION: Pulmonary embolism mortality remains high despite improvements in diagnostic and therapeutic management. It is important for our country to take these results into consideration for a better management of patients admitted for pulmonary embolism, and to improve survival.

[Spontaneous pneumothorax associated with ankylosing spondylitis]. / Pneumothorax spontané au cours de la spondylarthrite ankylosante.

Ankylosing spondylitis (AS) is a chronic inflammatory disease that affects the axial skeleton and more frequently the sacro-iliac joints. Pleuropulmonary involvement is an uncommon event. Apical fibrosis, interstitial infiltrates, and pleural thickening are thought to be the main patterns. Rare cases of spontaneous pneumothorax were reported in the literature. A 62-year-old man, who had a diagnosis of AS since May 1994, was admitted for exertional dyspnea. The diagnosis of apical fibrosis related to AS was essentially based on radiological arguments. The patient was again hospitalized in 2011 for thoracic pain. Computed tomography of the chest revealed a right partial pneumothorax. The evolution was marked by the total regression of the pneumothorax under oxygen and strict rest.