University of Algiers Benyoucef Benkhedda

Abstract An innovative approach is required in the energy industry to address the well cementing process in order to minimize the operation's carbon footprint. Typically, ordinary Portland cement is used as a well barrier to isolate oil and gas wells. The energy-intensive manufacturing process of Portland cement creates approximately 1 metric tonne of carbon dioxide emissions per metric tonne of cement produced. This paper discusses a cement-free geopolymer technology that can be used as a cement replacement and tailored for different well conditions. The formulations discussed in this paper reduce the embodied carbon emissions compared to a traditional cementing job, while also providing slurry and set properties adequate for isolation. The objective of this paper is to present two case histories of this unique cement-free geopolymer technology. These were the first jobs pumped using this technology in Europe, and the paper will detail the fit-for-purpose design methodology, as well as the job preparation, yard trial, and field execution. The geopolymer system discussed in this paper has been applied in over 750 jobs globally in various configurations, including plug and abandonment. The aim of this particular project was to demonstrate that the cement-free geopolymer technology is scalable and versatile across a range of conditions while providing slurry and set material properties that permit it to perform as an adequate wellbore barrier in the European market, as well as following industry guidelines such as API (American Petroleum Institute) Recommended Practice 10B-2. Four separate geopolymer slurries designed for plug and abandonment operations were optimized for different well conditions, including varied temperatures due to uncertainty in plug depth. Once optimized in the laboratory, the scalability of the geopolymer technology was assessed by preparing the material using conventional cementing equipment in three different locations in Europe. The flowability and homogeneity of scaled bulk plant blends of varying designs were verified by collecting multiple samples for analysis and comparison with laboratory-prepared blends. A yard trial demonstration of bulk mixing and pumping these fluids using conventional cementing equipment was completed in one country, and then plug jobs were successfully executed and verified in two other countries’ field locations in Europe. The cement-free geopolymer system demonstrated reliable adaptability to varying well conditions, consistent performance, and compatibility with conventional cementing equipment and workflows. Field operations successfully mixed, pumped, and verified the plugs, validating that this cement-free geopolymer technology can be deployed at scale. Replacing Portland cement with geopolymer materials offers a viable path toward more sustainable wellbore barrier systems, reducing environmental impact while preserving the high fluid performance and operational simplicity required in the field.

Abstract Radio Frequency (RF) jamming is a prevalent threat in Mobile Ad-hoc NETworks (MANETs), yet effective detection on resource-constrained nodes remains challenging. This paper presents a distributed three-tier edge-fog-cloud framework leveraging lightweight machine learning for real-time detection across heterogeneous devices. A priority-based adaptation algorithm dynamically allocates computational tasks based on node capabilities. The framework achieves detection accuracies of 85.6% (edge/ lightweight Random Forest), 88.8% (fog/compressed Random Forest), and 97.8% (cloud/LightGBM). The dynamic adaptation mechanism enables efficient load distribution, reducing energy consumption by 66.9% compared to static cloud deployment with only an 8.2% accuracy cost. Cross-dataset validation on two independent physical-layer datasets – covering weak jamming and deceptive attacks under vehicular mobility (10-60 km/h) – demonstrates exceptional robustness with <1% mean accuracy variance, validating the framework’s effectiveness in dynamic, resource-constrained MANET environments.

Musculoskeletal ultrasound has become an essential tool in the management of rheumatoid arthritis (RA), particularly for early diagnosis, assessment of disease activity, treatment monitoring, and decision-making during remission. It also contributes to improving the accuracy of interventional procedures. In Maghreb countries, its use has expanded significantly through local and international training initiatives. In this article, the Maghreb Committee of Experts in Rheumatologic Imaging (CEMIR) proposes practical recommendations, tailored to the regional context, to optimize the use of ultrasound in RA at all stages of patient management.

<title>Abstract</title> This study focuses on the valorization of agro-industrial waste for water treatment applications. Pomegranate peels were employed as a biosorbent for the removal of the anionic textile dye Solophenyl Blue GL (SB) from aqueous solutions. The materials were characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and determination of the point of zero charge (pHₚzc). The results showed that SB dye undergoes denaturation under highly acidic conditions, leading to its decomposition into toxic amine compounds that pose environmental risks. Batch adsorption experiments were conducted to investigate the effects of various parameters, including moisture, ash and volatile matter contents, specific surface area, solution pH, adsorbent dosage, initial dye concentration, salt effect, and contact time. Biomaterial optimization was achieved through chemical and physical modifications. Chemically activated materials (PEGa) were prepared by NaOH impregnation (1 M), while activated carbon (PEGc) was produced by pyrolysis of pomegranate peel powder (PEGb) at 500°C. A comparative adsorption study of the native, chemically activated, and calcined materials under identical conditions demonstrated that dye biosorption was enhanced at pH values below the pHₚzc due to electrostatic attraction, whereas it was inhibited at pH values above the pHₚzc because of electrostatic repulsion. The adsorption affinity followed the order: calcined (PEGc) &gt; activated (PEGa) &gt; native (PEGb). Overall, calcined pomegranate peel biochar (PEGc) appears to be a promising, low-cost adsorbent for the removal of persistent anionic dyes from water.