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The role of the turbulence in the void fraction distribution in bubbly pipe flow under microgravity condition is evaluated on the basis of numerical simulations using a Eulerian-Eulerian two-fluid model. In microgravity, the average relative velocity is weak and the void fraction distribution is mainly governed by the turbulence. The simulations show that the turbulent contributions of the added mass force play an important role in the phase distribution phenomenon. It is clearly proved that the turbulence acts on the bubbles distribution not only by the pressure term but also by the turbulent correlations obtained by averaging the added mass force. [DOI: 10.1115/1.1514212]

The objective of the research is to explore the predictability of water resources directly with GCMs by analysing long-term effects of climate change on Northern Tunisia’s blue and green water. Hydrologic impacts rely on a rainfall-runoff lumped model using outputs of CMIP6 GCMs within the framework of the ssp2-45 scenario. Among the 30 CMIP6 models, the composite cnrm-esm2-1 and fgoals-g3 best restore observed runoff from 1995 to 2014 and give the best GCM. Hydrologic projections 2015–2100 show significant drops in rainfall (9%), runoff (21%), groundwater recharge (15%), as well as for green water (6%). The results show that the use of raw GCMs predictions on large basins is possible and provides precisions comparable to what is produced when using Regional Climate Models in medium size basins.

First and second turbulence models for turbulent bubbly flows are implemented in the CFD code. In the second order turbulence closure, the Reynolds stress tensor of the continuous phase is split into two parts: a turbulent part produced by the gradient of the mean velocity and a pseudo-turbulent part induced by the bubbles displacements; each part is predetermined by a transport equation. The turbulent viscosity issued from this modeling takes into account the excess of the agitation and the supplementary eddies stretching due to the bubbles displacements. First order turbulence closure based on this turbulent viscosity is deduced and a three-equation turbulence model (k, ks, epsilon) is developed. We present the most prominent steps of the modeling and of its implementation in the CFD code then we comment the application of the model in the two homogeneous turbulent flows (uniform and uniformly sheared bubbly flows). [ABSTRACT FROM AUTHOR]

Numerous uncertainty factors in dispersion models should be taken into account in order to improve the reliability of predictions. The ability of a mesoscale meteorological model to assimilate observational data is an efficient way to improve operational air quality model forecasts. In this study, local weather data assimilation based on a flux-adjusting surface data assimilation system (FASDAS) is introduced to a Gaussian atmospheric dispersion model for a period with reported stable meteorological conditions. After evaluating the vulnerabilities of FASDAS, a combined data assimilation method is proposed to simultaneously improve the model weather prediction and retrieve the representation of accurate concentration distributions for short-range dispersion modeling against a control run. The two main uncertainty parameters considered are the wind speed and direction. A twin experiment demonstrates that the combined technique effectively improves the distribution of simulated concentrations. Comparison between results before and after the implement of data assimilation demonstrates that discrepancies between the reference simulation and the model forecast are mitigated after introducing the combined method, with more than 70 % of the predictions within a factor of two of the measurements. The errors in wind predictions in the FASDAS influenced the dispersion calculations, and the implementation of wind data assimilation in conjunction with the FASDAS has an indirect effect on further alleviating pollutant transport modeling errors.

Surgical management of long-gap esophageal atresia (LGEA) remains challenging. Yet, there is a consensus among pediatric surgeons to preserve native esophagus. We used a new surgical technique to successfully manage three children diagnosed with LGEA. This technique consists of a combined thoracic and cervical approach to the EA repair using the patient's native esophagus. All patients initially had had gastrostomy and continuous upper pouch suction while awaiting surgery. This new technique has the potential to become the choice method in LGEA management., Competing Interests: There are no conflicts of interest.

Background: Congenital epidermolysis bullosa (CEB) is a rare genodermatosis. The digestive system is very frequently associated with skin manifestations. Pyloric atresia (PA) and oesophageal stenosis (OS) are considered the most serious digestive lesions to occur.The aim of this work is to study the management and the outcome of digestive lesions associated to CEB in four children and to compare our results to the literature., Patients and Methods: A retrospective study of four observations: Two cases of PA and two cases of OS associated to CEB managed in the Paediatric Surgery Department of Fattouma Bourguiba Teaching Hospital in Monastir, Tunisia., Results: Four patients, two of them are 11 and 8 years old, diagnosed as having a dystrophic epidermolysis bullosa since the neonatal period. They were admitted for the investigation of progressive dysphagia. Oesophageal stenosis was confirmed by an upper contrast study. Pneumatic dilation was the advocated therapeutic method for both patients with a favourable outcome. The two other patients are newborns, diagnosed to have a CEB because of association of PA with bullous skin lesions with erosive scars. Both patients had a complete diaphragm excision with pyloroplasty. They died at the age of 4 and 3 months of severe diarrhoea resistant to medical treatment., Conclusion: Digestive lesions associated to CEB represent an aggravating factor of a serious disease. OS complicating CEB is severe with difficult management. Pneumatic dilatation is the gold standard treatment method. However, the mortality rate in PA with CEB is high. Prenatal diagnosis of PA is possible, and it can help avoiding lethal forms.

Background: Wound infection is the most frequent complication in burn patients. There is a lack of guidelines on the use of systemic antibiotics in children to prevent this complication., Patients and Methods: A prospective study is carried out on 80 patients to evaluate the role of antibiotic prophylaxis in the control of infections., Results: The mean age was 34 months (9 months to 8 years). There was a male predominance with sex ratio of 1.66. The mean burn surface size burn was 26.5% with total burn surface area ranging from 5% to 33%, respectively. According to American Burn Association 37% (30/80) were severe burns with second and third degree burns >10% of the total surface body area in children aged <10 years old. Scalds represented 76.2% (61/80) of the burns. Burns by hot oil were 11 cases (13.7%), while 8 cases (10%) were flame burns. The random distribution of the groups was as follow: Group A (amoxicilline + clavulanic acid) = 25 cases, Group B (oxacilline) = 20 cases and Group C (no antibiotics) = 35 cases. Total infection rate was 20% (16/80), distributed as follow: 8 cases (50%) in Group C, 5 cases (31.2%) in Group A and 3 cases in Group B (18.7%). Infection rate in each individual group was: 22.9% (8 cases/35) in Group C, 20% (5 cases/25) in Group A and 15% (3 cases/20) in Group B (P = 0.7). They were distributed as follow: Septicaemia 12 cases/16 (75%), wound infection 4 cases/16 (25%). Bacteria isolated were with a decreasing order: Staphylococcus aureus (36.3%), Pseudomonas (27.2%), Escherichia coli (18.1%), Klebsiella (9%) and Enterobacteria (9%). There is a tendency to a delayed cicatrisation (P = 0.07) in case of hot oil burns (65.18 ± 120 days) than by flame (54.33 ± 19.8 days) than by hot water (29.55 ± 26.2 days). Otherwise no toxic shock syndrome was recorded in this study., Conclusion: It is concluded that adequate and careful nursing of burn wounds seems to be sufficient to prevent complications and to obtain cicatrisation. Antibiotics are indicated only to treat confirmed infections.

Background: Lipoblastoma is a rare benign mesenchymal tumour of embryonal fat that occurs almost exclusively in infants and children. This determined the epidemiological, clinical and therapeutic aspect of this disease., Materials and Methods: A total of 10 cases of pathologically proven lipoblastoma from 2003 to 2012 were reviewed., Results: There were six boys and four girls ranging in age from 7 months to 9 years. A soft-tissue mass was the main complain in nine patients. The various locations of the mass were mediastinal, thigh, buttock, inguino-scrotal, the greater omentum and the Latissimus dorsi. Lesions measured 5-15 cm. complete excision was done. The median time of follow-up was 42 months (ranges between 18 and 84 months). There were no recurrences., Conclusion: It is important to consider lipoblastoma in the diagnosis of a rapidly enlarging fatty mass in children. Complete resection is the only definitive treatment and should not be delayed when impingement on surrounding structures is imminent. There is a tendency for these lesions to recur despite presumed complete excision. Therefore, follow-up for a minimum of 5 years is recommended.

Renal hydatid disease is rare in children. Open surgery is the traditional method of treatment, but minimally invasive techniques are being increasingly used. Herein, we report our experience with laparoscopic management of renal hydatid cyst in four children via a transperitoneal approach in three cases and a retroperitoneoscopy in one. We conclude that transperitoneal laparoscopy can be offered for the management of hydatid renal cyst associated with other intraperitoneal localizations, whereas the retroperitoneoscopy is limited for the treatment of isolated hydatid renal cysts., (Copyright © 2013 Elsevier Inc. All rights reserved.)

An infant with congenital pancreatic cyst with Ivemark II syndrome is reported because it is a rare association. The infant had associated situs inversus, asplenia, and complex congenital heart disease. The pancreatic cyst was successfully managed by cystoduodenostomy because of connection to the biliary tract. The infant succumbed as a result of heart failure at age 2 months. Prognosis depends on the presence of life-threatening malformations., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objective: Abdominal tuberculosis is one of the most frequent extra-pulmonary localizations. Its diagnosis is difficult and may lead to a delayed prescription of specific treatment. This study is aimed at stressing the role of laparoscopy associated with a biopsy in the diagnostic confirmation of abdominal tuberculosis particularly in doubtful cases., Methods: The diagnostic features of 11 cases hospitalized for abdominal tuberculosis in the Paediatric Surgery Department of Fattouma Bourguiba Hospital in Monastir for a 6-year period (2001-2006), were evaluated retrospectively. The diagnosis of abdominal tuberculosis was substantiated histopathologically by laparoscopy in all cases. The epidemiological and clinical characteristics along with the laboratory, radiological and histological data were studied., Results: Eleven cases of abdominal tuberculosis with a mean age of 5.6 years were diagnosed. It was peritoneal tuberculosis in all cases and associated with intestinal localization in one case. A conversion to laparotomy was practiced in three patients: appendicular plastron in one case, pseudo-tumor aspect of an intestinal loop in another case and because of their pathological aspect appendicectomy and caecum biopsy in the third. The diagnosis was confirmed histologically by biopsies in nine cases and on excision pieces in the other two cases. All patients had an uneventful course with an antituberculosis treatment., Conclusion: Abdominal tuberculosis is still frequent in Tunisia. Because of its non-specific clinical presentation and the limited means of investigation, a laparoscopy with biopsy should be practiced as first line diagnostic tool in case of doubtful abdominal tuberculosis. The earlier the diagnosis is established and an adapted antituberculosis treatment is started, the better the prognosis is.