Search Results (417)

This study presents a combined numerical and experimental analysis of heat and mass transfer in mare’s milk during vacuum sublimation drying, which is a process essential for producing high-quality powdered products. The numerical model was developed using two-dimensional simulations and validated against experimental data obtained for varying sample thicknesses (3 mm, 5 mm, and 7 mm). Results demonstrated a strong agreement between the model and experimental temperature data, with a coefficient of determination ($R^2$) of 95% during the sublimation process. The findings revealed that thinner samples (3 mm) exhibited a 20% faster drying rate than thicker samples (7 mm), highlighting the critical role of sample thickness in sublimation dynamics. Additionally, the effects of heat flux distribution and mass loss due to sublimation were analyzed to understand the drying dynamics. This study highlights the importance of optimizing process parameters such as chamber pressure, shelf temperature, and sample thickness to enhance drying efficiency and reduce processing time. The findings provide valuable insights for scaling vacuum sublimation drying of mare’s milk for industrial applications. Full article

We report the synthesis and characterization of new, user-friendly gold(I) [Au₄(μ-(NH)₂CC₂F₅)₄]_n coordination polymer and [Au₂Cl₂(NH₂(NH=)CC₂F₅)₂]_n complex. These compounds were investigated for potential application as precursors in chemical vapor deposition (CVD) and focused electron/ion beam-induced deposition (FEBID/FIBID), which are additive methods to produce nanomaterials. Single-crystal X-ray diffraction, elemental analysis, and infrared spectroscopy were used to determine the complexes’ composition and structure. We studied their thermal stability and volatility using thermal analysis and variable-temperature infrared spectroscopy (VT IR) and by conducting sublimation experiments. The gold(I) amidinate [Au₂(μ-(NH)₂CC₂F₅)₂]_n sublimates at 413 K under 10⁻² mbar pressure. The electron-induced decomposition of the complexes’ molecules in the gas phase and of their thin layers on silicon substrates was analyzed using electron impact mass spectrometry (EI MS) and microscopy studies (SEM/EDX), respectively, to provide insights for FEBID and FIBID precursor design. The [Au₂Cl₂(NH₂(NH=)CC₂F₅)₂]_n hydrogen chloride molecules evolved during heating, with the formation of gold(I) amidinate. The obtained results revealed that the new gold(I) amidinate may be a promising source of metal for nanomaterial fabrication by gas-assisted methods. Full article

It is necessary to overcome the relatively low conductivity of ionic liquids (ILs) caused by steric hindrance effects to improve their ability to passivate defects and inhibit ion migration to boost the photovoltaic performance of perovskite solar cells (PSCs). Herein, we designed and prepared a kind of low-concentration 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF₄) diluted with propylene carbonate (PC) via an ultrasonic technique (PC/IL). The decrease in the decomposition temperature related to the IL part and the increase in the sublimation temperature related to the PC part facilitated the use of PC/IL to effectively delay the crystallization process and passivate the defects in multiple ways to obtain high-quality perovskite films. Moreover, the increased conductivity of PC/IL and the more matched band alignment accelerated electron transport and collection. Finally, the MAPbI₃- and CsMAFA-based PSCs achieved PCE values of 20.87% and 23.29%, respectively, and their stabilities were greatly improved. This work provides a promising approach to optimizing ILs to achieve multiple functions and boost the performance of PSCs. Full article

Super Typhoon Mujigae (2015) was simulated using the WRF-ARW model version 4.1 with the WSM3, WSM5, WSM6, and WSM7 microphysics schemes, which include 3, 5, 6, and 7 hydrometeor classes, respectively. This study investigated the species number of hydrometeors (SNHs) from simple to complex on the rapid intensification (RI) of a tropical cyclone (TC). SNHs significantly affected the distribution of hydrometeors, microphysical conversion processes (MCPs), latent heat budget, and the interaction between thermal and dynamic processes, thereby influencing the RI. Different SNHs resulted in varied MCPs and a latent heat budget. The WSM3 and WSM5 schemes share the same top three dominating MCPs: condensation of cloud water (COND), accretion of cloud water by rain (RACW), and evaporation of rain (REVP). COND, accretion of cloud water by graupel (GACR), and RACW contributed to the WSM6 scheme. The WSM7 scheme included hail, with contributions from the instantaneous melting of snow, graupel, and COND, respectively. The dominating latent cooling processes were identical, while in different orders, which were evaporation of rain (REVP), sublimation of snow (SSUB), and evaporation of cloud water (CEVP) in the WSM3 and WSM5 schemes; while CEVP, REVP, and SSUB were in the WSM6 and WSM7. The interaction between thermal and dynamic processes was ultimately responsible for the RI. The WSM6 scheme presented an excellent latent heating rate, warm-core structure, and secondary circulation, which enhanced convection and absolute angular momentum transportation, and further indicating RI. The results highlighted the importance of an adequate complexity microphysics scheme to better reproduce the RI. Full article

Spray freeze drying (SFD) represents an emerging drying technique designed to produce a wide range of pharmaceuticals, foods, and active components with high quality and enhanced stability due to their unique structural characteristics. This method combines the advantages of the well-established techniques of freeze drying (FD) and spray drying (SD) while overcoming their challenges related to high process temperatures and durations. This is why SFD has experienced steady growth in recent years regarding not only the research interest, which is reflected by the increasing number of literature articles, but most importantly, the expanded market adoption, particularly in the pharmaceutical sector. Despite its potential, the high initial investment costs and complex operational requirements may hinder its growth. This paper provides a comprehensive review of the SFD technology, highlighting its advantages over conventional drying techniques and presenting its latest applications focused on pharmaceuticals. It also offers a thorough examination of the principles and the various parameters influencing the process for a better understanding and optimization of the process according to the needs of the final product. Finally, the current limitations of SFD are discussed, and future directions for addressing the economic and technical barriers are provided so that SFD can be widely industrialized, unlocking its full potential for diverse applications. Full article

Polymers with micro- and mesoporous structure are promising as materials for gas storage and separation, encapsulating agents for controlled drug release, carriers for catalysts and sensors, precursors of nanostructured carbon materials, carriers for biomolecular immobilization and cellular scaffolds, as materials with a low dielectric constant, filtering/separating membranes, proton exchange membranes, templates for replicating structures, and as electrode materials for energy storage. Sol–gel technologies, track etching, and template synthesis are used for their production, including in micelles of surfactants and microemulsions and sublimation drying. The listed methods make it possible to obtain pores with variable shapes and sizes of 5–50 nm and achieve a narrow pore size distribution. However, all these methods are technologically multi-stage and require the use of consumables. This paper presents a review of the use of macromolecular architecture in the synthesis of micro- and mesoporous polymers with extremely high surface area and hierarchical porous polymers. The synthesis of porous polymer frameworks with individual functional capabilities, the required chemical structure, and pore surface sizes is based on the unique possibilities of developing the architecture of the polymer matrix. Full article

Background: The Internet of Things (IoT) has improved many aspects that have impacted the industry and the people’s daily lives. To begin with, the IoT allows communication to be made across a wide range of devices, from household appliances to industrial machinery. This connectivity allows for a better integration of the pervasive computing, making devices “smart” and capable of interacting with each other and with the corresponding users in a sublime way. However, the widespread adoption of IoT devices has introduced some security challenges, because these devices usually run in environments that have limited resources. As IoT technology becomes more integrated into critical infrastructure and daily life, the need for stronger security measures will increase. These devices are exposed to a variety of cyber-attacks. This literature review synthesizes the current research of artificial intelligence (AI) technologies to improve IoT security. This review addresses key research questions, including: (1) What are the primary challenges and threats that IoT devices face?; (2) How can AI be used to improve IoT security?; (3) What AI techniques are currently being used for this purpose?; and (4) How does applying AI to IoT security differ from traditional methods? Methods: We included a total of 33 peer-reviewed studies published between 2020 and 2024, specifically in journal and conference papers written in English. Studies irrelevant to the use of AI for IoT security, duplicate studies, and articles without full-text access were excluded. The literature search was conducted using scientific databases, including MDPI, ScienceDirect, IEEE Xplore, and SpringerLink. Results were synthesized through a narrative synthesis approach, with the help of the Parsifal tool to organize and visualize key themes and trends. Results: We focus on the use of machine learning, deep learning, and federated learning, which are used for anomaly detection to identify and mitigate the security threats inherent to these devices. AI-driven technologies offer promising solutions for attack detection and predictive analysis, reducing the need for human intervention more significantly. This review acknowledges limitations such as the rapidly evolving nature of IoT technologies, the early-stage development or proprietary nature of many AI techniques, the variable performance of AI models in real-world applications, and potential biases in the search and selection of articles. The risk of bias in this systematic review is moderate. While the study selection and data collection processes are robust, the reliance on narrative synthesis and the limited exploration of potential biases in the selection process introduce some risk. Transparency in funding and conflict of interest reporting reduces bias in those areas. Discussion: The effectiveness of these AI-based approaches can vary depending on the performance of the model and the computational efficiency. In this article, we provide a comprehensive overview of existing AI models applied to IoT security, including machine learning (ML), deep learning (DL), and hybrid approaches. We also examine their role in enhancing the detection accuracy. Despite all the advances, challenges still remain in terms of data privacy and the scalability of AI solutions in IoT security. Conclusion: This review provides a comprehensive overview of ML applications to enhance IoT security. We also discuss and outline future directions, emphasizing the need for collaboration between interested parties and ongoing innovation to address the evolving threat landscape in IoT security. Full article

Adolescence is a time of elation and sublime emotions which are also reflected in partner relationships, within a context characterised by materialism and social structures in which gender relations are affected by the domination/subordination model. This paper analyses the affective-sexual relationships of adolescents as a place of violence, power relations, domination and submission. It also studies the importance of social networks in their way of interacting and learning. The methodology used was, on the one hand, the review of bibliographic material regarding romance, partner relationships, gender violence and using of networks, and, on the other hand, the analysis of the results obtained from two studies carried out by the University of Granada, with quantitative and qualitative information on adolescents in Andalusia. The results of this research indicate that relationships are permeated by the idealisation of romantic love and by stereotypes leading to practices of control and possession. Full article

Background: Proteins are commonly used in the healthcare industry to treat various health conditions, and most proteins are sensitive to physical and chemical changes. Lyophilization, also known as freeze-drying, involves sublimating water in the form of ice from a substance at low pressure, forming a freeze-dried powder that increases its shelf life. Extreme pressure and varying temperatures in the freeze-drying process may damage the protein’s structural integrity. Lyoprotectants are commonly used to protect protein conformations. It is important to choose a suitable lyoprotectant to ensure optimal effectiveness. Method: Twenty articles screened from Scopus, Web of Science, and PubMed were included in this review that discussed potential lyoprotectants and their effectiveness with different protein models. Results: Lyoprotectants were categorized into sugars, polyols, surfactants, and amino acids. Lyoprotectants can exhibit significant protective effects towards proteins, either singularly or in combination with another lyoprotectant. They exert various interactions with the protein to stabilize it, such as hydrogen bonding, hydrophobic interactions, electrostatic interactions, and osmoprotection. Conclusions: This review concludes that disaccharides are the most effective lyoprotectants, while other groups of lyoprotectants are best used in combination with other lyoprotectants. Full article

Block lifting is a key step in stabilizing and removing fragile remains at archaeological excavation sites. Due to its favorable working properties and adhesive effect, menthol has recently been proposed as a volatile binding medium for temporary consolidation in archaeological conservation. This paper presents a case study on the use of menthol in the extraction and restoration of a large wooden coffin lid, approximately 1.9 m long and 0.9 m wide, from tomb 11 (M11) at Xie’ertala, located east of a Xie’ertala town in Hailar City, Inner Mongolia, dating to the 7th to 10th centuries CE. This coffin lid had fragmented into numerous wooden pieces, and was preserved in a relatively arid steppe environment, necessitating the extraction of the lid as a consolidated block. The use of menthol for consolidating and lifting the highly fragmented wooden coffin lid was intended to preserve critical archaeological information while avoiding damage to the underlying objects. An analysis of the physicochemical properties of these wooden remains suggests that the timber used for the coffin lid belongs to a common pine species from the Hulunbuir region. The degradation of the coffin lid was relatively mild, as shown by Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscope (SEM) results. Dynamic Vapor Sorption (DVS) tests indicated that the hygroscopicity of the archaeological wood was 23.4%, compared to 21.1% for the reference sample, demonstrating good environmental stability. The safety of menthol as a treatment for fragile wooden remains was evaluated by comparing changes in the morphological and porosity characteristics of the coffin lid before and after menthol treatment. After treatment, the widths of the fissures remained largely unchanged, with all relative variations being less than 1%, and the porosity as well as pore size distribution of the wood showed negligible changes. Gas Chromatography–Mass Spectrometry (GC-MS) results showed that only 0.6% of menthol residue remained after 8 days of sublimation. This pilot study demonstrates that menthol is a safe temporary consolidant for block lifting and offers a promising alternative to the widely used cyclododecane. In conclusion, this research provided a new approach for conservators to safely lift similarly large and fragile wood remains during archaeological excavations. Full article

Ecocriticism is an advancing field in literature that has opened up avenues in reading world literature from a whole new perspective. This paper seeks to flesh out ecocritical concerns in the selected poems of Mahmoud Darwish and Naomi Shihab Nye by using selected concepts of the theory of ecocriticism given by Greg Garrard: pastoral, wilderness, and the sublime. An analysis of the poetry by the selected writers, sharing their roots from the Arab world, reveals their agenda of using nature as a trope in the form of resistance to colonialism. The writers give a glimpse of the people of their homeland and their culture imbued in nature. Full article

In her 2010 article “Aesthetic Wit(h)nessing in the Era of Trauma”, Griselda Pollock lamented the aperture between psychology, particularly that of PTSD, and esthetics in the search to bear witness to traumatic experience. This article explores the gray area that exists when the esthetic and the traumatic converge, arguing that such areas exist not only as direct representations of the difficulty of narrativizing trauma as described by such theorists as Cathy Caruth, Onno van der Hart, and Bessel van der Kolk, but also simultaneously as windows into the moments of what Dominick LaCapra calls “the sublime object of endless melancholia and impossible mourning”. Postmodernism is argued to be the organic choice of voicing traumatic retellings, and close readings of John Hersey’s proto-postmodern Hiroshima (1946), Tim O’Brien’s The Things They Carried (1992), and David Foster Wallace’s Infinite Jest (1996) work to highlight the intersections of trauma, postmodern literature, and esthetics; or, in Wallace’s case, theoretical discussions of traumatic tropes as facilitated by the postmodern tradition. In drawing attention to this tripartite convergence, this article hopes to continue in the vein of scholarship that reaffirms the need for evermore research in the field of trauma studies as well as substantiate a claim of the heightened importance of postmodern literature in the 21st century—an epoch indelibly marked by trauma, as noted by Pollock. Full article

The synthesis and characterisation (UV-Vis, IR, HRESI-MS, ¹H and ¹³C NMR spectroscopies, electrochemistry) is reported of the novel title material (1: alternatively named rac-1-(2′-benzothiazolyl)-2-ferrocenyl-2-propanol): a rare example of a ferrocenyl-benzothiazole hybrid species. Compound 1 is produced by the low temperature reaction of acetylferrocene (3) with a solution of the methyl anion derived via the deprotonation of 2-methyl-1,3-benzothiazole. The yield of 1 is moderate (34%) after purification and is an air and thermally stable solid under ambient conditions. Attempts to sublime 1, however, result in decomposition with one of the products being identified (NMR) as 3. The spectroscopic features of 1 are presented. Attempts to obtain suitable crystalline material of 1 for a single crystal X-ray diffraction study were unfortunately unsuccessful. Compound 1 also does not form stable coordination complexes with various metal salts (e.g., Ni[2+], Co[2+], etc.) under the conditions tested. Full article

Metal oxide core–shell fibrous nanostructures are promising gas-sensitive materials for the detection of a wide variety of both reducing and oxidizing gases. In these structures, two dissimilar materials with different work functions are brought into contact to form a coaxial heterojunction. The influence of the shell material on the transportation of the electric charge carriers along these structures is still not very well understood. This is due to homo-, hetero- and metal/semiconductor junctions, which make it difficult to investigate the electric charge transfer using direct current methods. However, in order to improve the gas-sensing properties of these complex structures, it is necessary to first establish a good understanding of the electric charge transfer in ambient air. In this article, we present an impedance spectroscopy study of networked SnO₂/Ga₂O₃ core–shell nanobelts in ambient air. Tin dioxide nanobelts were grown directly on interdigitated gold electrodes, using the thermal sublimation method, via the vapor–liquid–solid (VLS) mechanism. Two forms of a gallium oxide shell of varying thickness were prepared via halide vapor-phase epitaxy (HVPE), and the impedance spectra were measured at 189–768 °C. The bulk resistance of the core–shell nanobelts was found to be reduced due to the formation of an electron accumulation layer in the SnO₂ core. At temperatures above 530 °C, the thermal reduction of SnO₂ and the associated decrease in its work function caused electrons to flow from the accumulation layer into the Ga₂O₃ shell, which resulted in an increase in bulk resistance. The junction resistance of said core–shell nanostructures was comparable to that of SnO₂ nanobelts, as both structures are likely connected through existing SnO₂/SnO₂ homojunctions comprising thin amorphous layers. Full article

This paper presents the results of laboratory studies for the distillation of mercury from depleted coal sorbents produced in gold recovery factories using CIP technology. The mercury content in these materials is more than 1%. The developed technology was tested in a large-scale laboratory on a pilot vacuum sublimation electric furnace with the rheological movement of dispersed material. The use of this equipment makes it possible to demercurize various materials with fairly high moisture (up to 20%). It eliminates the use of an additional technological operation—drying the material in a vacuum drying oven. It has been shown that a high degree of mercury distillation is achieved (more than 99.8%) at 350–400 °C in the reaction space and residual pressure in the system of less than 1.33 kPa, with residual mercury content in the material of less than 0.001% (10 mg/kg), which complies with the European environmental standards. Mercury-free coal sorbents are sent for combustion for the additional extraction of precious metal composites. The proposed vacuum technology is characterized by its environmental safety because the process is performed in sealed equipment, eliminating toxic emissions of mercury vapor into the atmosphere. The proposed vacuum technology equipment is characterized by reliability and ease of use. Full article