Search Results (412)

Synthetic jets, generated through the periodic suction and ejection of fluid without net mass addition, offer distinct benefits, such as compactness, ease of integration, and independence from external fluid sources. These characteristics make them well-suited for flow control and convective heat transfer applications. However, conventional single-actuator configurations are constrained by limited jet formation, narrow surface coverage, and diminished effectiveness in the far field. This review critically evaluates the key limitations and explores four advanced configurations developed to mitigate them: dual-cavity synthetic jets, single-actuator multi-orifice jets, coaxial synthetic jets, and synthetic jet arrays. Dual-cavity synthetic jets enhance volume flow rate and surface coverage by generating multiple vortices and enabling jet vectoring, though they remain constrained by downstream vortex diffusion. Single-actuator multi-orifice designs enhance near-field heat transfer through multiple interacting vortices, yet far-field performance remains an issue. Coaxial synthetic jets improve vortex dynamics and overall performance but face challenges at high Reynolds numbers. Synthetic jet arrays with independently controlled actuators offer the greatest potential, enabling jet vectoring and focusing to enhance entrainment, expand spanwise coverage, and improve far-field performance. By examining key limitations and technological advances, this review lays the foundation for expanded use of synthetic jets in practical engineering applications. Full article

The growing demand for renewable fuels has renewed interest in biodiesel production, prompting exploration beyond conventional reactors. This review assesses three-dimensional (3D) printed microreactors for biodiesel synthesis via transesterification, with a focus on their potential for enhanced process efficiency, sustainability, and modular deployment. Compared with conventional batch and stirred-tank reactors, 3D-printed microstructured systems often offer superior mass and heat transfer, enabling biodiesel yields up to ~99% in some studies, with critically short residence times (e.g., as low as ~5 s) and reported energy reductions of 60% to 90% under optimal conditions. Optimized configurations in recent work achieved energy requirements as low as ~0.05 to 0.12 kWh L⁻¹, substantially lower than the typical 0.25 to 0.60 kWh L⁻¹ for conventional setups. However, existing studies remain limited in number and scope: issues such as catalyst leaching, chemical and thermal stability of printing materials, dimensional inaccuracies, and scalability of microreactor networks remain under-investigated. Long-term durability, real-world feedstock variation (e.g., high-FFA waste oils), and comprehensive lifecycle assessments are often lacking, limiting confident extrapolation to industrial scale. Despite these challenges, the emerging evidence suggests significant promise for 3D-printed microreactors as a pathway toward modular, energy-efficient, and potentially low-carbon biodiesel production, provided that future work addresses their practical limitations and validates performance under industrially realistic conditions. Full article

Existing experimental findings often prove insufficient for guiding the design of water mist fire extinguishing systems, primarily due to the multitude of interacting factors that influence extinguishing performance. This paper systematically synthesizes these factors and delineates their logical interrelationships based on the extinguishing mechanisms of water mist and a review of the existing literature. The analysis focuses on direct influencing factors by modeling the motion, heat transfer and mass transfer of water mist within the flame zone. The results indicate that, when the influence of the fire flame is negligible, the required velocity and droplet diameter of water mist entering the zone can be determined based on the flame temperature differential and flame height. When plume effects are significant, water mist predominantly enters the flame zone from the top and periphery. Under such conditions, determining the mist velocity and diameter should aim to maximize the total heat absorption power of droplets entering via these two pathways. This study provides a theoretical foundation for the design of a water mist fire extinguishing system. Full article

As the power density of microelectronic devices and components continues to increase, thermal management has become a critical bottleneck limiting their performance and reliability. With its advantages of effective heat dissipation, no need for external power, and good safety, the micro pulsating heat pipe (MPHP) exhibits unique application advantages and enormous development potential when compared to other cutting-edge thermal management solutions, such as embedded microchannel cooling technology, which has complicated manufacturing processes and is prone to leakage, or thermoelectric material cooling technology, which is limited by material efficiency and self-heating. However, a pulsating heat pipe (PHP) is vulnerable to the combined impacts of several elements (scale effects, wall effects, and interfacial effects) at the micro-scale, which can lead to highly variable heat transfer characteristics and complex two-phase flow behavior. There are still few thorough experimental reviews on this subject, despite the fact that many researchers have concentrated on the MPHP and carried out in-depth experimental investigations on their flow and heat transmission mechanisms. In order to provide strong theoretical support for optimizing the design of the MPHP cooling devices, this paper reviews previous experimental research on the MPHP with the goal of thoroughly clarifying the mechanisms of gas–liquid two-phase flow and heat/mass transfer within them. The definition of MPHP is first explained, along with its internal energy transmission principles and structural features. The motion states of gas–liquid two-phase working fluids in the MPHP from previous experimental investigations are then thoroughly examined, highlighting their distinctive flow patterns and evolution mechanisms. Lastly, the variations in thermal performance between different kinds of MPHPs are examined, along with the factors that affect them. Full article

While organolithium reactions hold great promise in synthetic chemistry, their high reactivity, strong exothermicity, and the instability of intermediates often limit their application, making the effective control of reaction processes difficult in traditional batch reactors. This review systematically summarizes the latest advances in utilizing flow chemistry technology to address process challenges related to organolithium reactions from 2014 to 2025. From a process perspective, we systematically discuss the literature cases regarding three key themes: the synthesis of organic compounds applied in the pharmaceutical field, the development of novel methods centered on effective process control (reaction temperature, residence time, phase state, multi-step reaction sequence, and safety), and fundamental process research on continuous flow organolithium reactions. Analysis shows that continuous flow systems provide a powerful platform for fully realizing the potential of organolithium chemistry by enhancing heat/mass transfer and precisely controlling reaction parameters. This review emphasizes how flow chemistry technology not only improves process safety and efficiency but also enables transformations and process scaling that are difficult or impossible in batch modes, thus providing a novel process intensification method for modern synthetic chemistry. Full article

Tablet film coating is governed by three interrelated phenomena, namely, tablet mixing, coating-liquid spraying, and liquid evaporation, which dominate the critical quality attributes ($CQAs$) of the final product. This review examines how differences in coater design, key process parameters, and quality control strategies impact these phenomena and ultimately affect inter-tablet and intra-tablet coating variability. Two complementary approaches for understanding and optimizing the process are evaluated. The experimental approach, involving Design of Experiments (DoE), retrospective data analysis, and advanced Process Analytical Technology ($PAT$), provides empirical insight into factor–response relationships and enables real-time quality assurance. Simultaneously, model-based approaches, including thermodynamic, spray-dynamics, and particle-dynamics modelling, offer mechanistic understanding of heat and mass transfer, droplet deposition patterns, and tablet motion. Although these sub-models have advanced considerably over the years, a predictive model that treats the coating process in its entirety is still missing. Overall, this review underscores that future advancements will require integrating experimental and model-based methodologies to achieve robust, quality-driven, and predictive control of tablet film coating processes. Full article

This review highlights the growing relevance of ion-exchange nanofibrous membranes (IEX-NFMs) in membrane chromatography (MC) for protein purification, emphasising their structural advantages such as high porosity, tunable surface functionality, and low-pressure drops. While the adsorption of IEX-NFMs in MC is expanding due to their potential for high throughput and rapid mass transfer, a critical limitation remains: the precise binding capacity of these membranes is not well understood. Traditional experimental methods to evaluate protein–membrane interactions and optimise binding capacities are labour-intensive, time-consuming, and costly. Therefore, this review underscores the importance of computational modelling as a viable predictive approach to guide membrane design and performance prediction. Yet major obstacles persist, including the challenge of accurate representation of the complex and often irregular pore structures, as well as limited and/or oversimplified adsorption models. Along with molecular-scale simulations such as molecular dynamics (MD) simulations and quantum simulations, meso-scale simulations can provide insight into protein–fibre and protein–protein interactions under varying physicochemical conditions for larger time scales and lower computational burden. These tools can help identify key parameters such as binding accessibility, ionic strength effects, and surface charge density, which are essential for the rational design and performance prediction of IEX-NFMs. Moreover, integrating simulations with experimental validation can accelerate optimisation process while reducing cost. This technical review sets the foundation for a computationally driven design framework for multifunctional IEX-NFMs, supporting their use in next-generation chromatographic separations and broadening their applications in bioprocessing and analytical biotechnology. Full article

Utilization of ozone micro-nano bubbles during uranium leaching process has attracted attention in recent years because of ozone’s potent oxidizing capacity, high efficiency in mass transfer, and environmental compatibility. This review systematically presents the properties, generation methods and characterization approaches pertaining to ozone micro-nano bubbles (OMNBs) for the application of uranium leaching. In addition, the potentials and challenges of using ozone micro-nano bubbles to enhance uranium resources recovery are summarized. A lack of comprehensive understanding regarding uranium oxidation mechanism by ozone micro-nano bubbles under different pH conditions, along with the gaps in field experiments, has hindered the exploration and development of uranium leaching by OMNBs. In summary, further research endeavors on uranium oxidation mechanism by OMNBs and field trials are needed to facilitate the implementation of uranium leaching by OMNBs. Full article

Polyhydroxybutyrate (PHB), as a biodegradable and green polymer, holds significant potential for replacing traditional petroleum-based plastics. However, its production efficiency and cost remain bottlenecks limiting large-scale application. In recent years, hybrid systems constructed from photosensitive nanomaterials and microorganisms have provided a novel pathway for enhancing PHB synthesis efficiency. These systems augment the supply of intracellular reducing power through efficient photo-generated electron injection, thereby driving microbial carbon fixation and PHB anabolic metabolism. This review systematically summarizes the mechanisms and performance of various types of photosensitive materials (including g-C₃N₄, CdS, polymer dots, etc.) in regulating PHB synthesis in microorganisms, such as Cupriavidus necator H16. It focuses on the influence of material composition, structure, energy band characteristics, and their interfacial interactions with microorganisms on electron transfer efficiency and biocompatibility. Furthermore, the article outlines the current challenges faced by these hybrid systems in key energy and mass transfer processes, including light energy conversion, transmembrane electron transport, and NADPH regeneration. It also prospects the design principles of novel bio-inspired multi-level heterojunction materials and their application potential in constructing efficient “material microbe” collaborative synthesis systems. This review aims to provide a material-level theoretical foundation and design strategies for developing high-performance and sustainable light-driven biomanufacturing technologies for PHB. Full article

Buildings are under increasing pressure to address decarbonization and climate adaptation, which is pushing design practice from post hoc performance checks to performance-driven generative design (PDGD). This review maps the current state of PDGD in buildings and proposes an engineering-oriented framework that links research methods to deployable workflows. Using a PRISMA-based systematic search, we identify 153 core studies and code them along five dimensions: design objects and scales, objectives and metrics, algorithms and tools, workflows, and data and validation. The corpus shows a strong focus on facades, envelopes, and single-building massing, dominated by energy, daylight and thermal comfort objectives, and a widespread reliance on parametric platforms connected to performance simulation software with multi-objective optimization. From this evidence we extract three typical workflow routes: parametric evolutionary multi-objective optimization, surrogate or Bayesian optimization, and data- or model-driven generation. Persistent weaknesses include fragmented metric conventions, limited cross-case or field validation, and risks to reproducibility. In response, we propose a harmonized objective–metric system, an evidence pyramid for PDGD, and a reproducibility checklist with practical guidance, which together aim to make PDGD workflows more comparable, auditable, and transferable for design practice. Full article

Microbial electrolysis cells (MECs) are bioreactors that utilize electroactive microorganisms to catalyze the oxidation of organic substrates in wastewater, generating electron flow for hydrogen production. Despite the concept, a persistent performance gap exists where metabolically active anodic biofilms frequently fail to achieve expected current densities by the flow of electrons to produce hydrogen. This review examines the multiple causes that lead to the disconnect between robust biofilm development, electron transfer, and hydrogen production. Factors affecting biofilm generation (formation, substrate selection, thickness, conductivity, and heterogeneity) are discussed. Moreover, factors affecting electron transfer (electrode configuration, mass transfer constraints, key electroactive species, and metabolic pathways) are discussed. Also, substrate diffusion limitations, proton accumulation causing inhibitory pH gradients in stratified biofilms, elevated internal resistance, electron diversion to competing processes like hydrogenotrophic methanogenesis consuming H₂, and detrimental biofilm aging, impacting hydrogen production, are studied. The critical roles of electrode materials, reactor configuration, and biofilm electroactivity are analyzed, emphasizing advanced electrochemical (CV, EIS, LSV), imaging (CLSM, SEM, AFM), and omics (metagenomics, transcriptomics, proteomics) techniques essential for diagnosing bottlenecks. Strategies to enhance extracellular electron transfer (EET) (advanced nanomaterials, redox mediators, conductive polymers, bioaugmentation, and pulsed electrical operation) are evaluated for bridging this performance gap and improving energy recovery. The review presents an integrated framework connecting biofilm electroactivity, EET kinetics, and hydrogen evolution efficiency. It highlights that conventional biofilm metrics may not reflect actual electron flow. Combining electrochemical, microelectrode, and omics insights allows precise evaluation of EET efficiency and supports sustainable MEC optimization for enhanced hydrogen generation. Full article

Heat exchangers–adsorbers (HEX-As) are emerging as innovative technologies in many applications (CO₂ capture, gas purification and separation, thermal energy storage, etc). This review addresses the theoretical challenges within computational fluid dynamics (CFD) in modeling and simulating coupled heat and mass transfer within gas separation by using adsorbing porous media in fixed beds. Conservation equations of mass, momentum, and energy from different studies (1D, 2D-CFD, and 3D-CFD models) are presented and discussed with an emphasis on their ability to predict the complex multi-physics multi-scale heat and mass transfer phenomena involved, such as the adsorption kinematics, the thermal front propagation, and the multi-component fluid flow dynamics inside the beds. For the fist time, we show that mathematical theoretical modeling in CFD has been differently developed and applied by many authors in the literature in order to model the same physical phenomena. This sheds light on the present challenges and bottlenecks in theoretical and computational fluid dynamics when it comes to complex coupled heat and mass transfer in multi-component gas dynamics in porous media. This review make it easier for readers to understand the different models that exist in the literature for modeling and simulating HEX-As. It also opens questions on how accurately one can model multi-functional heat exchangers–adsorbers using CFD, e.g., physics multi-scale extrapolation from nano- to meso- and then to macro-scale behavior. Full article

The paper presents the model, methodology and results of experimental research focused on identification of the wave form generated during the crossing of 30-ton and 60-ton vehicles on a ribbon-type pontoon bridge and the analysis of its influence on the characteristics of the maximum draught. A review of the literature revealed that ribbon-type pontoon bridges are subject to significant vertical deflection. This results from the need to generate sufficient buoyant force to balance the weight of crossing vehicles. The area of maximum draught occurs directly beneath the vehicle and moves along with it, generating a front wave—referred to as a bow wave—which propagates along the crossing and alters the local draught of individual pontoons. Due to the fact that pontoon bridges transfer loads through buoyancy force, a key issue in the process of their design is the precise knowledge of the formation of the volume of the droughted part. No information was found in any publication about the influence of the front wave on the draught form of a ribbon-type pontoon bridge. Their authors do not indicate that the analytical or simulation models they use reflect this phenomenon. Equally, the analysis of the methodologies and results of experimental studies in this area did not show that any attempts were made to identify the form of the front wave. The paper presents the results of measurements of vertical displacements of individual pontoon blocks of the crossing and the characteristics of the front wave occurring during the passing of 30- and 60-ton vehicles with speeds ranging from 7.4 to 30 km/h. Based on the obtained data, an attempt was made to identify the phenomenon of undulation of the surface of the water obstacle and its impact on the loads on the bridge structure. The results allow for identifying a significant front wave with a wavelength of 30–50 m, appearing clearly at speeds above 21 km/h. This wave substantially affects the draught measurement—at a speed of 25 km/h, the maximum draught increased by approximately 30%. Statistical analysis confirmed the significance of this effect (p < 0.05), indicating that wave formation must be considered for accurate determination of pontoon block draught. Furthermore, the mass of the vehicle had a strong influence on the wave and draught parameters—the 60-ton vehicle produced wave troughs and draught depths 55–65% greater than those of the 30-ton vehicle. Full article

Despite the recognized potential of pulsating fluidized beds (PFBs), a systematic review that links pulsation parameters to macroscopic enhancements and the underlying microscopic mechanisms is currently lacking. This review addresses this gap by first synthesizing how pulsating airflow can surpass traditional fluidization in reducing the minimum fluidization velocity (Umf), improving bed stability, and precisely regulating bubble dynamics. Furthermore, we demonstrate that the frequency of pulsation influences particle mixing and separation efficiency, while the amplitude of pulsation has a direct effect on heat and mass transfer. Importantly, we identify a critical knowledge gap: there is insufficient understanding of the microscopic interactions—such as inter-particle collision dynamics and local force networks—that underpin these macroscopic phenomena. This work establishes a foundational framework that connects operational parameters to multiscale outcomes, thereby guiding future research toward targeted optimization of PFB systems. Full article

This study presents the results of a multi-technique forensic investigation of suspicious soft capsules seized by law enforcement during a criminal case. The unlabeled samples, sold as therapeutic and “regenerative” food supplements, were examined using liquid chromatography–tandem mass spectrometry (LC-MS/MS), Fourier-transform infrared spectroscopy with attenuated total reflection (ATR-FTIR), chemiluminescence, and brightfield/confocal microscopy. These complementary analytical approaches revealed that the capsules contained biological material of unknown origin, including blood-derived compounds, lipid constituents, and cellular structures. The findings indicate biological adulteration, possibly due to deliberate falsification or severe contamination. To place these results in a broader biomedical context, a scoping review of literature on blood- and tissue-derived materials used in biomedical and nutraceutical applications was conducted. This review underscores how such products are developed, promoted, and regulated, highlighting the potential health and biosafety risks associated with unregulated biologically themed supplements. Overall, this study demonstrates a transferable analytical workflow suitable for forensic laboratories and emphasizes the need for continued regulatory vigilance to protect public health. Given the evidentiary constraints typical of forensic casework—specifically, the small amount of seized material—the workflow was optimized to maximize information yield through minimally destructive, orthogonal, non-genetic screening methods, with LC-MS/MS reserved for final molecular confirmation. DNA typing was not performed because, after confirmatory analyses, the remaining material was insufficient for reliable genotyping. Full article