Peri-urban settlements are characterized by inadequate wastewater management. Decentralized wastewater management systems are promising alternatives for reducing pollution from untreated sewage entering receiving water bodies, but the social, economic, and environmental conditions in peri-urban settlements require careful technology selection to ensure sustainability. Several domestic wastewater technology selection tools exist; however, these are typically designed for either urban or rural contexts. For this reason, this work proposes a decentralized wastewater technology selection tool for the context of peri-urban settlements that includes participation of local stakeholders in decision-making. The tool includes a technical component with three stages that involve multicriteria methods based on the Analytical Hierarchy Process and Montecarlo simulation to reduce uncertainty: i) decision according to context (settlement population, settlement typology, energy availability); ii) superior decision levels (nine sub-criteria from technical, environmental and economic dimensions); iii) technical and economic feasibility (dimensioning; cost of investment, operation and maintenance; availability to pay). The tool proposes a social strategy throughout the entire process to ensure stakeholder participation, aiming to strengthen capacities and knowledge co-production for informed technology selection. The tool was validated in a peri-urban settlement of Bucaramanga (Colombia), showing robustness and soundness. This innovative approach contributes to the search for sustainable solutions by facilitating the use of systematic tools by technicians and professionals in these contexts. A multi-criteria tool for the participatory selection of wastewater treatment technologies for settlements was developed. The tool included technical, environmental, social, and economic pre-feasibility variables under uncertain scenarios. Validation of the tool in a case study confirmed its robustness and relevance for use in developing countries.
Plastic waste presents a critical environmental challenge but offers significant potential as a carbon-rich feedstock for valuable products. Pyrolysis, especially of high-density polyethylene (HDPE), has emerged as a promising technology to convert plastic waste into pyrolytic oil, gases, and recoverable monomers, supporting sustainable waste management and energy security across various economies. This study examines the technical and economic feasibility of HDPE pyrolysis at a pilot scale, with a focus on Colombia’s emerging waste management infrastructure. Laboratory experiments optimized key process parameters, including temperature, heating rate, and residence time, while Aspen Plus simulations provided essential insights into mass balance and energy efficiency. Results showed that pyrolysis at 550 °C yielded the highest liquid fraction (71.04
Embedded cryptography stands or falls on entropy quality, yet small devices have few trustworthy sources and little tolerance for heavyweight protocols. We build a Quantum Entropy as a Service (QEaaS) system that moves QRNG-derived entropy from a Quantis device to ESP32-class clients over post-quantum-secured channels. On the server side, the design exposes two paths: direct quantum entropy through a custom OpenSSL provider and mixed entropy through the Linux system pool. On the client side, we extend libcoap’s Zephyr support, integrate wolfSSL-based DTLS 1.3 into the CoAP stack, and add a BLAKE2s entropy pool that preserves the standard Zephyr extraction interface while introducing an injection API for server-provided entropy. Benchmarks on ESP32 hardware, targeting 100 iterations per configuration, show that ML-KEM-512 completes a DTLS 1.3 handshake in 313 ms on average without certificate verification, 35% faster than ECDHE P-256. Pairing ML-KEM-512 with ML-DSA-44 lowers the mean to 225 ms. Certificate verification adds roughly 194 ms for ECDSA but only 17 ms for ML-DSA-44, so the fully post-quantum configuration remains 63% faster than classical ECDHE P-256 with ECDSA even under full verification. Local BLAKE2s pool operations stay below 0.1 ms combined. On this platform, post-quantum key exchange and authentication are not only feasible; they are faster than the classical baseline.
In this work, we examine the kinematic vortex state in a mesoscopic superconducting membrane under the influence of an applied direct current and an external magnetic field. The analysis focuses on the velocity of the vortex-antivortex state, the resistivity curves as functions of the externally applied current, and the time evolution of the Cooper pair density at different current levels. The sample features a thin incrustation composed of a material with a lower superconducting critical temperature, enabling the control of vortex dynamics within the membrane. Using the generalized time-dependent Ginzburg-Landau model for a two-dimensional superconducting membrane, we found that the number of pinning centers significantly influences the vortex dynamics and the magnetic response of the sample. It is observed that, as pairs within defects approach each other in a double-system scenario, they mutually attract in a manner reminiscent of the behavior of Josephson vortices. In the cases studied, our results show that the applied current creates a barrier that induces the attraction of π -type vortices. The defects in the sample are crucial for the design of devices used in industry and engineering.
The botanical origin of honey strongly influences its chemical composition and bioactive properties, making authentication essential for quality assurance and consumer trust. Conventional methods, such as physicochemical and chromatographic analyses, are accurate but often time-consuming and require sophisticated instrumentation. This study proposes an integrated approach combining electrochemical fingerprinting with established techniques to deliver a rapid, cost-effective, and reliable strategy for honey authentication. Two tropical honeys with distinct botanical origins, including a monofloral Ziziphus mauritiana honey and a Haematoxylum campechianum-rich multifloral honey were characterized using Fourier-transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC), Karl Fischer titration, and cyclic voltammetry (CV). FTIR provided general compositional profiles, while HPLC and Karl Fischer revealed significant differences in sugar and moisture content. CV generated distinct electrochemical signatures, enabling clear discrimination of botanical origin and reflecting variations in reducing sugars and minor redox-active compounds. These findings highlight the potential of voltammetric analysis as a complementary tool to conventional and melissopalynological methods for honey authentication and traceability. We recommend this integrated approach to enhance regulatory compliance and food integrity, particularly in regions with limited access to advanced analytical resources.
