Search Results (698)

The increasing share of heavy and high-sulfur crude oils in refinery feed slates worldwide highlights the need for models of delayed coking units (DCUs) that are both physically meaningful and computationally efficient. In this study, we develop and calibrate a simplified yet dynamic one-dimensional model of an industrial coke drum intended for integration into digital twin frameworks. The model includes a three-phase representation of the drum contents, a temperature-dependent global kinetic scheme for vacuum residue cracking, and lumped descriptions of heat transfer and phase holdups. Only three physically interpretable parameters—the kinetic scaling factors for distillate and coke formation and an effective wall temperature—were calibrated using routinely measured plant data, namely the overhead vapor and drum head temperatures and the final coke bed height. The calibrated model reproduces the temporal evolution of the top head and overhead temperatures and the final bed height with mean relative errors of a few percent, while capturing the more complex bottom-head temperature dynamics qualitatively. Scenario simulations illustrate how the coking severity (represented here by the effective wall temperature) affects the coke yield, bed growth, and cycle duration. Overall, the results indicate that low-order dynamic models can provide a practical balance between physical fidelity and computational speed, making them suitable as mechanistic cores for digital twins and optimization tools in delayed coking operations. Full article

Hydrogen-based energy systems require large amounts of high-purity water, motivating thermally driven desalination that can recover low-grade heat. This study evaluates a silica gel–water adsorption chiller–desalination unit as a coupled source of cooling and pre-treated water for electrolysers. A laboratory two-bed system was tested on saline feed using 300 s valve-switching periods at an 80 °C driving temperature and 20–30 °C cooling water. Dynamic vapour sorption measurements provided Dubinin–Astakhov equilibrium and linear driving force kinetic parameters, implemented in a CFD porous bed model via user-defined source terms. Experiments yielded COP values of 0.29–0.41, an SCP of 165 W·kg⁻¹ of adsorbent, and an average distillate production of 1.68–1.82 kg·h⁻¹, while distillate conductivity remained ≈2.3 μS·cm⁻¹. The model reproduced the mean condensate production with a ≈6% underprediction. It was then used to compare six alternative fin geometries with a constant heat-transfer area. Fin-shape modifications changed inter-fin heating by <2 K and cumulative desorbed mass by <0.05%, indicating limited sensitivity to subtle local refinements. Performance gains are more likely to arise from operating conditions and exchanger-scale architecture than from minor fin-shape changes. Full article

In this study, a hybrid sensor based on a defective square-truncated patch antenna (STPA) and a frequency-selective surface (FSS) was analyzed numerically and experimentally for different glucose–distilled water solutions. Here, an FSS was employed to enhance the sensitivity of the hybrid sensor. The sensing principle relies on monitoring variations in the loss tangent ($tan\delta$) and relative permittivity (${\epsilon }_r$) caused by different glucose concentrations applied to the sample under test (SUT). An open-ended coaxial probe was used to measure the complex permittivity of the solutions, which was then fitted to the Debye relaxation model. The simulated and experimental results of the novel sensor showed good agreement in a glucose concentration monitoring application. The sensor spanned the glucose range from 0 mg/dL to 5000 mg/dL, exhibiting a sensitivity of 55.44 kHz/mgdL⁻¹ and a figure of merit (FOM) of 6.23 × ${10}^{-4}$ (1/mgdL⁻¹) in the experiments and 53.60 kHz/mgdL⁻¹ and 1.71 × ${10}^{-4}$ (1/mgdL⁻¹) FOM in the simulations. When solutions with different concentrations were tested in the SUT, the resonance frequency of the antenna ($f_0$, in GHz) changed. To further characterize the sensor response, the relationship between the glucose concentration (C, in mg/dL) and $f_0$ was examined. A regression-based prediction model was constructed to map the measured scattering parameters to the glucose concentration, yielding a coefficient of determination ($R^2$) of 0.976. The high sensitivity, compact size, and compatibility with planar fabrication suggest that the proposed hybrid sensor has the potential to contribute to the development of non-invasive glucose-monitoring systems. Full article

Acoustic-based anomaly detection in elevators is crucial for predictive maintenance and operational safety, yet it faces significant challenges in real-world settings, including pervasive multi-source acoustic interference within confined spaces and severe class imbalance in collected data, which critically degrades the detection performance for minority yet critical acoustic events. To address these issues, this study proposes a novel hierarchical self-distillation framework. The method embeds auxiliary classifiers into the intermediate layers of a backbone network, creating a deep teacher–shallow student knowledge transfer paradigm optimized jointly via Kullback–Leibler divergence and feature alignment losses. A self-attentive temporal pooling layer is introduced to adaptively weigh discriminative time-frequency features, thereby mitigating temporal overlap interference, while a focal loss function is employed specifically in the teacher model to recalibrate the learning focus towards hard-to-classify minority samples. Extensive evaluations on the public UrbanSound8K dataset and a proprietary industrial elevator audio dataset demonstrate that the proposed model achieves superior performance, exceeding 90% in both accuracy and F1-score. Notably, it yields substantial improvements in recognizing rare events, validating its robustness for elevator acoustic monitoring. Full article

In an effort to evaluate the performance of a 5-gallon pot still in separating yeast-derived congeners during the distillation of a grain-based distiller’s beer, the distillates of a fermented mash of cracked corn, malted barley, and wheat were characterized using ¹H NMR spectroscopy and GC-MS. A quantitative comparison using these two techniques is uncommon. Results revealed significant variation in congener concentrations across runs, with a notable discrepancy in the third run possibly due to bacterial contamination, as indicated by high 1-propanol levels. Key congeners, such as acetaldehyde, ethyl acetate, furfural, phenylethanol, and 1,1-diethoxyethane, showed expected distillation behavior across ten fractions, based on their respective boiling points. However, methanol and 1-propanol showed a fairly flat concentration profile across all ten fractions, while those for ethyl octanoate and ethyl hexanoate decreased rapidly and were undetected at fraction 5. White dog (unaged whiskey) fractions from column and combination stills were also analyzed, and the results demonstrate that the small 5-gallon still separates congeners as well as these stills. Finally, a comparison of congener concentrations demonstrates that NMR and GC-MS do not yield identical concentrations of congeners, despite exhibiting similar trends in congener concentrations in the fractions from the still, with GC-MS suggesting higher levels. Full article

Background/Objectives: The ¹⁰³Pd/^103mRh in vivo generator represents a promising Auger electron-emitting system, in which both parent and daughter radionuclides emit predominantly Auger electrons with minimal accompanying radiation. This study investigates the release dynamics of daughter radionuclides from the ¹⁰³Pd/^103mRh in vivo generator and evaluates the underlying mechanisms governing bond rupture and daughter retention. Methods: Cyclotron irradiation of rhodium foils was performed in two separate batches, followed by radionuclide separation using conventional wet chemistry and a novel dry distillation technique. The purified ¹⁰³Pd radionuclide was used to radiolabel DOTA-TATE, phthalocyanine-TATE, and DOTA-TOC chelators. The resulting complexes were immobilized on Strata-X and Strata-C18 solid-phase extraction columns. Scheduled elution experiments were conducted to quantify the release of the ^103mRh daughter radionuclide. Results: The measured ^103mRh release rates were 9.8 ± 3.0% and 9.6 ± 2.7% from Strata-X columns with DOTA-TATE and phthalocyanine-TATE, respectively, and 10.5 ± 2.7% and 12.0 ± 0.5% from Strata-X and Strata-C18 columns, respectively, with DOTA-TOC. These values are significantly lower than the ~100% release predicted based on the reported Auger electron yield of 186%. One explanation for this difference could be potential inconsistencies in decay data that may require correction; this needs further investigation. The results further demonstrated that delocalized π-electrons, introduced via phthalocyanine-based chelation, did not mitigate daughter release. Conclusions: The low observed daughter nuclide release represents a favorable characteristic for the future clinical translation of the ¹⁰³Pd/^103mRh Auger emitter pair. The findings support the conclusion that Auger electron cascades, rather than nuclear recoil energy, dominate bond rupture processes. Full article

Accurate carbon footprint accounting is essential for advancing carbon management and optimising energy systems. However, existing uncertainty analyses are often difficult to reproduce and interpret because the underlying evidence is scattered across multiple sources, thereby making it hard to attribute uncertainty to specific drivers. To address this gap, we propose a transparent uncertainty quantification framework that (i) distills multi-source evidence into auditable rules, (ii) propagates ambiguity through fuzzy aggregation, and (iii) maps interval outputs to probabilistic representations for scenario-based Monte Carlo simulation. In the case study, the proposed method yields more stable carbon footprint estimates than conventional approaches, with lower variability across repeated simulations, and it enables clearer uncertainty attribution by separating random variation from structural uncertainty. Overall, this paper provides a traceable and interpretable method for high-precision uncertainty quantification in carbon footprint assessment. Full article

The increasing volume of produced water (PW) generated by oil extraction activities has intensified the need for environmentally sustainable strategies that enable its reuse and valorization. Biotechnological approaches, particularly those involving the microbial production of value-added compounds, offer a promising route for transforming PW from an industrial waste into a useful resource. In this context, bacterial exopolysaccharides (EPS) have gained attention due to their diverse functional properties and applicability in bioremediation, bioprocessing and petroleum-related operations. This study evaluated the potential of Lelliottia amnigena to synthesize EPS using oilfield PW as a component of the culture medium in stirred-tank bioreactors. Three conditions were assessed: a control using distilled water (dW), PW diluted to 25% (PW25%) and dialyzed PW (DPW). Batch experiments were conducted for 24 h, during which biomass growth, EPS accumulation and dissolved oxygen dynamics were monitored. Post-cultivation analyses included elemental and monosaccharide composition, scanning electron microscopy and rheological characterization of purified EPS solutions. EPS production varied among treatments, with dW and DPW yielding approximately 9.6 g L⁻¹, while PW25% achieved the highest productivity (17.55 g L⁻¹). The EPS samples contained fucose, glucose and mannose, with compositional differences reflecting the influence of PW-derived minerals. Despite reduced apparent viscosity under PW25% and DPW conditions, the EPS exhibited physicochemical properties suitable for biotechnological applications, including potential use in fucose recovery, drilling fluids and lubrication systems in the petroleum sector. The EPS also demonstrated substantial adsorption capacity, incorporating salts from PW and contributing to contaminant removal. This study demonstrates that PW can serve both as a substrate and as a source of functional inorganic constituents for microbial EPS synthesis, supporting an integrated approach to PW valorization. These findings reinforce the potential of EPS-based bioprocesses as sustainable green technologies that simultaneously promote waste mitigation and the production of high-value industrial bioproducts. Full article

Refinery blending is a routine operation, yet small changes in crude mix can strongly affect product yield and fuel quality. In this work, Aspen HYSYS v12.1 was used to model and optimize the blending of four Nigerian crude oils—Antan, Usan, Bonga, and Forcados—processed at about 150,000 barrels per day. The study examined how adjustments in blend ratio and feed temperature influence gasoline output and energy use in the distillation unit. The best result was obtained at a blend of Antan 10%, Usan 37.45%, Bonga 10%, and Forcados 42.55%, where gasoline yield increased by roughly 5.6% compared with the equal-blend case. Product properties remained within Nigerian fuel standards (RON ≈ 92, sulphur ≈ 0.038 wt%), showing that quality was not affected by the optimizations. Economic estimates also indicated higher annual revenue and a modest reduction in furnace heat duty, suggesting lower fuel consumption. Although the work was limited to steady-state simulation without plant-scale validation, it provides practical evidence that systematic crude blend optimizations can deliver measurable gains in yield and energy efficiency for refineries using mixed feedstocks. Full article

Freshwater scarcity is a critical global challenge, particularly in arid and semi-arid regions like southern Iraq. This study evaluates the thermal and distillate performance of a conventional single-slope solar still under extreme summer conditions in Basrah, Iraq. The objective is to analyze and validate a coupled theoretical–experimental model for predicting temperature fields and freshwater productivity. The model incorporates transient energy and mass balance equations with temperature- and salinity-dependent thermophysical properties. Experiments were conducted using brackish water from the Shatt al-Arab River (salinity: 5.2 g/kg), and measured temperatures and productivity were compared against simulations over a 24-h period. Strong agreement was achieved between experimental and theoretical results, with $R^2>0.90$ for temperature predictions and $R^2=0.985$ for hourly productivity. Maximum hourly yield reached $0.46\mathrm{L}/{\mathrm{m}}^2$, with a total daily productivity of $3.5\mathrm{L}/{\mathrm{m}}^2$, The daily thermal efficiency was found to be 26.90% experimentally and 28.20% theoretically. A positive linear relation between the thermal gradient $(T_{\mathrm{w}}-T_{\mathrm{g}})$ and hourly productivity was also established. The findings confirm the reliability of the developed model and highlight the potential of solar distillation as a sustainable freshwater source for high-temperature regions. Full article

To address the stochastic, nonlinear, and strongly coupled characteristics of multivariate long-term structural response in bridge health monitoring, this study proposes the Informer-SEnet prediction model. The model integrates a Squeeze-and-Excitation (SE) channel attention mechanism into the Informer framework, enabling adaptive recalibration of channel importance to suppress redundant information and enhance key structural response features. A sliding-window strategy is used to construct the datasets, and extensive comparative experiments and ablation studies are conducted on one public bridge-monitoring dataset and two long-term monitoring datasets from real bridges. In the best case, the proposed model achieves improvements of up to 54.67% in MAE, 52.39% in RMSE, and 7.73% in R². Ablation analysis confirms that the SE module substantially strengthens channel-wise feature representation, while the sparse attention and distillation mechanisms are essential for capturing long-range dependencies and improving computational efficiency. Their combined effect yields the optimal predictive performance. Five-fold cross-validation further evaluates the model’s generalization capability. The results show that Informer-SEnet exhibits smaller fluctuations across folds compared with baseline models, demonstrating higher stability and robustness and confirming the reliability of the proposed approach. The improvement in prediction accuracy enables more precise characterization of the structural response evolution under environmental and operational loads, thereby providing a more reliable basis for anomaly detection and early damage warning, and reducing the risk of false alarms and missed detections. The findings offer an efficient and robust deep learning solution to support bridge structural safety assessment and intelligent maintenance decision-making. Full article

A method for quantifying tebufenpyrad residues in greenhouse sandy loam soils was developed and validated. Given the strong sorption (high K_oc) of tebufenpyrad to mineral–organic domains in soils, desorption-limited and partially bound residues may occur, so sample preparation methods should actively promote desorption to minimize underestimation. The QuEChERS extraction procedure was optimized by adjusting pre-wetting volume and aqueous medium to enhance desorption prior to salt-induced acetonitrile partitioning. Pre-wetting volume markedly affected phase separation and recovery: acceptable ranges were 80.2–82.0% at 5–10 mL, 94.6% at 15 mL, and 99.1% at 20 mL, while a supra-quantitative value of 119.6% was observed at 25 mL, likely due to salt-induced contraction of the acetonitrile layer, which artificially concentrates tebufenpyrad. Among pre-wetting reagents, 15 mL of 0.05% HCl yielded the highest desorption in field soil (0.20 mg/kg), compared with distilled water (0.13 mg/kg), formic acid (0.16 mg/kg), and EDTA (0.14–0.17 mg/kg). The final method employed 15 mL of 0.05% HCl for pre-wetting, followed by acetonitrile extraction and MgSO₄/NaCl partitioning. Linearity (r² = 0.9990) was achieved over 1.25 to 100 ng/mL, with an LOQ of 0.005 mg/kg and average recoveries of 86.7%, 99.8%, and 98.5% at 0.01, 0.1, and 30 mg/kg, respectively (RSD ≤ 6.2%), satisfying SANTE criteria. In greenhouse soil, residues declined from 1.9 to 0.3 mg/kg at the recommended rate (1×) and from 4.8 to 0.7 mg/kg at the doubled rate (2×) within 46 d (DT₅₀ ≈ 20 d). This validated QuEChERS method provides a reliable analytical basis for evaluating tebufenpyrad dissipation in soil. Full article

Potassium (K) is a vital macronutrient for plant growth and yield, yet most soil K occurs in insoluble mineral forms, limiting availability to crops. Reliance on chemical K fertilizers is unsustainable due to cost and environmental concerns. Microbial solubilization of mineral K, particularly by purple nonsulfur bacteria (PNSB), offers an eco-friendly alternative. This study focused on isolating mica-potassium-solubilizing purple nonsulfur bacteria (MK-PNSB) from in-dyke alluvial soil and assessing their effects on hybrid maize germination and seedling growth. Among the isolates, the results showed that strain M-Wa-19 released the highest amount of soluble K under microaerobic light conditions (27.4 mg∙L⁻¹). Under aerobic dark conditions, M-Wa-24 and M-Wa-26 released 20.1–21.0 mg∙L⁻¹ of soluble K. Strains M-Wa-21, M-Wa-25, and M-Sl-13 solubilized K in the range of 14.3–25.1 mg∙L⁻¹ and 12.9–24.4 mg∙L⁻¹ under both incubation conditions. The selected strains were identified by 16S rRNA as Rhodopseudomonas palustris strain M-Sl-13 (PX588604), Rhodoplanes pokkaliisoli strain M-Wa-19 (PX588605), Afifella marina strain M-Wa-21 (PX588606), Rhodocista pekingensis strain M-Wa-24 (PX588607), Rhodocista pekingensis strain M-Wa-25 (PX588608), and Rhodocista pekingensis strain M-Wa-26 (PX588609). None exhibited toxicity to maize seeds; instead, all enhanced seed vigor indices by up to 99.7% and improved plant height and root biomass by 19.0–26.2% and 14.4–22.9%, respectively, under static hydroponic conditions. At a 1:1000 (bacteria and distilled water) dilution rate, strains M-Wa-26, M-Wa-25, M-Sl-13, M-Wa-24, M-Wa-19, and M-Wa-21, along with the six-strain mixture, improved seed vigor index by 3.96–7.91%. These findings suggest that MK-PNSB, individually or in mixtures, hold promise as biofertilizer candidates for sustainable K management in crop production. Full article

Cross-linked polyethylene (PEX) is very stable, both chemically and mechanically. This makes its waste difficult to process. A very promising approach is slow pyrolysis catalyzed by hematite (α-Fe₂O₃). Such pyrolysis was carried out on a large scale (feedstock of 38 kg, catalyst amount of 2 wt.%, heating rate of 4 K min⁻¹, end temperature of 435 °C, delay at the end temperature several hours) and provided an oil containing both liquid (up to C₁₇) and solid hydrocarbons (>C₁₇). Thus, the oil obtained can be a source of valuable chemicals, solvents, and paraffin, and/or used as a clean liquid fuel and/or as a source of lubricants. Pyrolysis of PEX also yielded energy gas (12 wt.%) and solid carbonaceous residue (15 wt.%) for further use. The process mass balance and parameters (temperature, heating rate, dwell time, catalyst amount), composition, and chemical (elemental analysis, XRF, GC-MS, GC, distillation curve) and physical (viscosity, density, higher and lower heating value) properties of the oil, gas, and solid carbonaceous residue obtained are presented and discussed. The main product of the proposed technology is oil with a yield of almost 73 wt.%. The by-products are energy gas (12 wt.%) and solid carbonaceous residue (15 wt.%). The results obtained showed that the proposed technology successfully recycles difficult-to-process PEX with a process efficiency of 70%. Full article

This work proposes the design, construction, and field test of a vacuum seawater desalination system (VSDS) driven by an evacuated tube solar collector (with a total absorption area of 1.86 m²) under tropical climatic condition (Thailand ambient at latitude 13°43′06.0″ N, longitude 100°32′25.4″ E). The VSDS prototype was designed and constructed to be driven by hot water, which is produced by two heat source conditions: (1) an electric heater for laboratory tests and (2) an evacuated tube solar collector for field tests under real climatic conditions. A comparative experimental study to assess the ability to produce fresh water between a conventional dripping/pipe feed column and spray falling film column is proposed in the first part of the discussion. This is to demonstrate the advantage of the spray falling film distillation column. The experimental method is implemented based on the batch system, in which the cycle time (distillation time) considered is 10–20 min so that heat loss via the concentrated seawater blow down is minimized. Later, the field test with solar irradiance under real climatic conditions is demonstrated to assess the freshwater yield and the system performance. The aim is to provide evidence of the proposed vacuum desalination system in real operation. It is found experimentally that the VSDS working with spray falling film provides better performance than the dripping/pipe feed column under the specified working conditions. The spray falling film column can increase the distillated freshwater volume from 1.33 to 2.16 L under identical cycle time and working conditions. The improvement potential is up to 62.4%. The overall thermal efficiency can be increased from 33.7 to 70.8% (improvement of 110.1%). Therefore, the VSDS working with spray falling film is selected for implementing field tests based on real solar irradiance powered by an evacuated tube solar collector. The ability to produce fresh water is assessed, and the overall performance via the average distillation rate and the thermal efficiency (or Gain Output Ratio) is discussed with the real solar irradiance. It is found from the field test with solar time (8.00–16.00) that the VSDS can produce a daily freshwater yield of up to 4.5 L with a thermal efficiency of up to 19%. The freshwater production meets the requirement for international standard drinking water criteria, indicating suitability for household/community use in tropical regions. This work demonstrates the feasibility of VSDS working under real solar irradiance as an alternative technology for sustainable fresh water. Full article