Société Tunisienne de l'Electricité et du Gaz (Tunisia)

The management of cadmium-rich sludges, which are pollutant residues from the phosphorus industry, including the valorization of these sludges through the selective recovery of heavy metals, is a promising prospect. However, there is still a need to develop recovery methods that are both optimized for efficiency, cost-effectiveness, and environmentally friendly. This study aims to enhance cadmium extraction from the polymetallic sludge by optimizing the processes of sulfuric acid (SA) leaching and sodiumsulfide precipitation. Key parameters including SA concentration, temperature, solid/liquid ratio, and stirring velocity were optimized to maximize the heavy metals extraction. Over 90% of the Cd and Zn present in the sludge were successfully extracted. Subsequently, investigates the selective precipitation of metal sulfide from acidic leachates (pH < 2), focusing particularly on cadmium. Through the optimization of chemical precipitation parameters (Na2S concentration, temperature, and reaction time), more than 99% of the cadmium was selectively recovered as CdS. The precipitates underwent analysis for mineralogy, chemistry, purity, and particle size. XRD analyses indicated CdS formation in "Greenockite" and "Hawleyite" forms, confirmed by SEM-EDS data, revealing fine powder consisting of micro and nanoparticles (< 0.5 µm) with varied spherical shapes.

Modeling of industrial production processes is becoming increasingly challenging due to their large number of variables. These variables often are highly correlated and introduce nonlinear and complex features. In this paper, we are interested to model an industrial dicalcium phosphate (DCP) drying process. Attempting to solve this issue is motivated by the need to improve several production conditions, such as minimizing the consumption of natural gas and reducing the pollution rate. In fact, applying an advanced control approach requires a dynamic model for the monitored plant. This work proposes a multivariable mathematical model for the DCP dryer within the Tunisian Chemical Group factory. A steady-state model has been reproduced using Aspen Plus software tool to implement the different functionalities of the system as well as involved reactions. Indeed, since the main operation in the drying process is the combustion reaction of the liquified petroleum gas (LPG) in the furnace that produce the necessary heat to reach a target value of temperature at the dryer outlet, we focus on determining a dynamic model for the furnace. To do so, we have proposed two approaches. The first is based on the Aspen dynamic tool. The second is based on the left matrix fraction description (LMFD) identification approach. The obtained results have been successfully validated using real measurements.

Abstract This study aimed to develop an energy‐efficient process for treating highly saline textile wastewater (TWW) in a 10 m3/day pilot plant and evaluate forage sorghum irrigation with treated wastewater in terms of crop production and soil and irrigation device performance. The TWW treatment pilot plant, consisting of a coagulation/flocculation unit followed by a sand filter and an anion exchange resin column, produced treated effluent that complied with the permissible limits specified in the ISO 16075‐2:2020 standard for Category C irrigation water. The corresponding average energy consumption was 1.77 kWh/m3. Reusing treated TWW for forage sorghum irrigation over a 13‐week cycle yielded crop performances comparable with freshwater irrigation, with no negative impact on the irrigation system. Although soil profiles were similar between treated TWW and freshwater irrigation, both soils featured an increase in electrical conductivity, which may reversibly or irreversibly affect soil quality and damage salt‐sensitive crops. These findings demonstrate the effective treatment and reuse of saline TWW for irrigating salt‐tolerant crops, offering significant implications for industrial wastewater management and cropping patterns in arid and semi‐arid regions.

Trauma to the lower cervical spine is a serious lesion due to its neurological consequences which jeopardize the vital and functional prognosis. They constitute a public health problem due to their frequency and seriousness requiring rapid and adequate treatment. The aim of our study is to (1) describe the epidemiological, clinical, and radiological characteristics of lower cervical spine trauma patients; (2) support the therapeutic management of these patients and show our experience in surgery for lower cervical spine trauma; and (3) analyze the anatomical and functional results and discuss them with literature data. This is a retrospective descriptive study of 50 patients with lower cervical spine trauma treated surgically over a period of five years from January 1, 2016, to December 2020. The average age of our patients was 34.5 years, with a sex ratio of 1.7. The etiologies are dominated by accidents on public roads (58%). They show neurological disorders such as spinal cord damage in 30% of cases and root damage in 20% of cases. The radiological assessment revealed eight tear drops, ten comminuted fractures, 12 severe sprains, 12 biarticular dislocations, six uniarticular dislocations, and two herniated discs. Treatment was surgical in all patients with an anterolateral approach and anterior arthrodesis. The evolution was favourable in 21 patients and stationary in 29 patients. Our study concluded that dislocations and fracture dislocations were the predominant type of injury in cases of AVP. Tetraplegia was mainly observed with uni- and biarticular dislocations. The variation in consolidation time was not correlated with trauma-to-surgery time. Better neurological recovery was observed with mild initial neurological damage than with initially severe damage. The appearance of an adjacent syndrome is less frequent with monosegmental arthrodesis than with multisegmental arthrodesis. Cage arthrodesis was an alternative to iliac harvesting with similar results.

This research article investigates the challenges associated to exceeding the hosting capacity of low voltage distribution lines and its impact on power quality and system stability. This work mainly focuses on the integration of photovoltaic systems into low voltage feeder, considering both commercial and residential consumers. The paper aims to evaluate the current and potential hosting capacity of the distribution line for future photovoltaic installations, with a specific focus on the transition of residential consumers into prosumers. Furthermore, the research highlights the impact of exceeding the hosting capacity on power quality and emphasizes the importance of adhering to power quality limits defined by grid codes and standards.

In this work, we present the performance of a solar photovoltaic plant located in Tozeur (Tunisia). This solar power plant connected to the HTA network of the Tunisian Electricity and Gas Company (STEG) is equipped with photovoltaic panels based on monocrystalline technology. By analyzing the performance indicators, it is possible to predict the limits and the constraints on the energy production and also to assess the environmental impact on the operating of this type of installation. For this purpose, sufficient data were collected over a period of 30 days for the analysis of the climate and of the performance parameters. The results obtained showed a satisfactory performance of the PV plant with a performance ratio (PR) of 86.32%, close to that of other plants also operating in desert conditions.

This article presents the hypothetical steps leading to the damage of power transformers in order to examine whether there is a correlation between the electrostatic properties (ECT) and the electro-hydrodynamic properties (EHD) of insulating oils. Vegetable oils such as, olive oil (OO) and sunflower oil (SO) have been tested as alternative oils for the insulation and cooling of transformers and their blends with naphthenic mineral oil (MO) on the basis of well-defined ratios and for a remarkable aging time, which is an original contribution and insight offered by this paper. The results obtained for the different mixtures with regard to the electrostatic properties and the electro-hydrodynamic properties as well as the physico-chemical properties (power factor “tgδ”, resistivity, conductivity and viscosity) in terms of the aging time were compared with that of the mineral oil. The study of the physico-chemical properties of insulating oils and their mixtures is carried out according to international standards.

The dynamic behavior of a hydraulic dual tube automobile strut damper is studied. The purpose is to explore the piston and cylinder valves softening on the damper force response for different excitation velocities. Indeed, an experimental investigation is conducted on a dual tube hydraulic damper for automobile front axle. A test bench is used to load the strut damper at different reference velocities, and to measure its dynamic response. The dynamic response diagrams are obtained in compression and in extension, for different reference configurations of the piston and cylinder valves. The results depend on the mechanical and the hydraulic parameters of the strut damper, but also on the testing conditions. First, the experimental results are analyzed, the force-displacement responses are examined to conclude on the calibration forces. Second, the calibration forces are checked, a force-velocity diagram is established to conclude on the force evolution with velocity. The effects of the piston and cylinder valves configuration and of the excitation velocity are determined, which helps to tune the damper design to the automobile requirements.

BackgroundLittle is known about the pattern and appropriateness of antibiotic prescriptions in patients with acute respiratory tract infections (ARTIs).ObjectiveDescribe the antibiotics used to treat ARTIs in Tunisian primary care offices and emergency departments (EDs), and assess the appropriateness of their use.MethodsIt was a prospective multicenter cross-sectional observational clinical study conducted at 63 primary care offices and 6 EDS during a period of 8 months. Appropriateness of antibiotic prescription was evaluated by trained physicians using the medication appropriateness index (MAI). The MAI ratings generated a weighted score of 0 to 18 with higher scores indicating low appropriateness. The study was conducted in accordance with the Declaration of Helsinki and national and institutional standards. The study was approved by the Ethics committee of Monastir Medical Faculty.ResultsFrom the 12,880 patients screened we included 9886 patients. The mean age was 47.4, and 55.4% were men. The most frequent diagnosis of ARTI was were acute bronchitis (45.3%), COPD exacerbation (16.3%), tonsillitis (14.6%), rhinopharyngitis (12.2%) and sinusitis (11.5%). The most prescribed classes of antibiotics were penicillins (58.3%), fluoroquinolones (17.6%), and macrolides (16.9%). Antibiotic therapy was inappropriate in 75.5% of patients of whom 65.2% had bronchitis. 65% of patients had one or more antibiotic prescribing inappropriateness criteria as assessed by the MAI. The most frequently rated criteria were with expensiveness (75.8%) and indication (40%). Amoxicillin-clavulanic acid and levofloxacin were the most inappropriately prescribed antibiotics. History of cardiac ischemia ([OR] 3.66; 95% [CI] 2.17–10.26; p < 0.001), asthma ([OR] 3.29, 95% [CI] 1.77–6.13; p < 0.001), diabetes ([OR] 2.09, 95% [CI] 1.54–2.97; p = 0.003), history of COPD ([OR] 1.75, 95% [CI] 1.43–2.15; p < 0.001) and age > 65 years (Odds Ratio [OR] 1.35, 95% confidence interval [CI] 1.16–1.58; p < 0.001) were associated with a higher likelihood of inappropriate prescribing.ConclusionOur findings indicate a high inappropriate use of antibiotics in ARTIs treated in in primary care and EDs. This was mostly related to antibiotic prescription in acute bronchitis and overuse of expensive broad spectrum antibiotics. Future interventions to improve antibiotic prescribing in primary care and EDs is needed.Trial registrationthe trial is registered at Clinicaltrials.gov registry (NCT04482231).