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A hydrodynamic theory of premixed flame propagation within closed vessels is developed assuming the flame is much thinner than all other fluid dynamic lengths. In this limit, the flame is confined to a surface separating the unburned mixture from burned combustion products, and propagates at a speed determined from the analysis of its internal structure. Unlike freely propagating flames that propagate under nearly isobaric conditions, combustion in a closed vessel results in continuous increases in pressure, burning rate and flame temperature, and a progressive decrease in flame thickness. The flame speed is shown to depend on the voluminal stretch rate, which measures the deformation of a volume element of the flame zone, and on the rate of pressure rise. Both effects are modulated by pressure-dependent Markstein numbers that depend on heat release and mixture properties while capturing the effects of temperature-dependent transport and stoichiometry. The model applies to flames of arbitrary shape propagating in general flows, laminar or turbulent, within vessels of general configurations. The main limitation of hydrodynamic flame theories is the assumption that variations inside the flame zone due to chemistry or turbulence, which could potentially alter its internal structure, are physically unresolved. Nonetheless, the theory, deduced from physical first principles, identifies the various mechanisms involved in the combustion process as demonstrated in detailed discussions of planar flames propagating in rectangular channels and spherically expanding flames in spherical vessels. It also enables the construction of instructive models to numerically simulate the evolution of multi-dimensional and corrugated flames under confinement.

In-house synthesized monosulfonated para-polybenzimidazole (s-p-PBI) was blended with commercially available disulfonated poly(arylene ether) sulfone (SPAES; SES0105, Aquafone™). The s-p-PBI was prepared from the polycondensation of 2-sulfoterepthalic acid and 3, 3ʹ-diaminobenzidine. The 1 H NMR spectroscopy confirms the formation of benzimidazole protons. Copolymer SPAES behaves as the electron-withdrawing polymer (sulfonic groups), and s-p-PBI as the electron-donating polymer (imidazole groups). The interactions between polymers are examined through Attenuated Total Reflectance-Fourier Transformed Infrared spectroscopy (ATR-FTIR), Thermogravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM). Tensile stress at maximum load of blend membrane containing 80% (w/w) of s-p-PBI and 20% (w/w) of SPAES (AM-AC-80) is 55.59 MPa, whereas pristine s-p-PBI (AM-AC-100) membrane is 45.35 MPa. The blend polymers were stable in boiling water. All the blend membranes were morphologically stable at 1500 ppm of NaOCl solution immersed for 24 h except for pristine s-p-PBI. The blend polymers showed improved tensile strength and stability in NaOCl solutions compared to pristine s-p-PBI. The blend membranes displayed improved salt rejection with decreasing water permeability. The intrinsic parameters for desalination performance were examined to correlate crosslinking with water and salt transport. AM-AC-80 shows a slight improvement in water diffusivity and a four-fold increase in permeability selectivity (water/NaCl) compared to pristine s-p-PBI.

Upon polycondensing, the monosodium salt of 2-sulphoterepthalic acid and 3,3′-diaminobenzidine resulted in sulphonated polybenzimidazole (s-p-PBI; amphiphilic polymer). The amphiphilic polymer was blended with commercially available sulphonated poly(arylene ether sulphone) (SPAES; acid polymer; IEC = 2.08 meq g −1 ). The s-p-PBI content in blend composition is varied from 2.5 to 30% (w/w). ATR-FTIR spectroscopy and TG analysis were examined to identify the interactions between the polymers upon blending. Cross-sectional morphology was analysed through SEM. With amphiphilic polymer addition, chlorine (hypochlorite) stability decreased and tensile strength improved. All the blend membranes showed improved water transport or restricted salt permeability than the pristine membrane (acid polymer). Water diffusivity permeability ( P w ) of blend membrane AC-AM-97.5 (i.e., 97.5% (w/w) of SPAES and 2.5% (w/w) of s-p-PBI) is 1.285 cm 2 s −1 , while the pristine membrane is 0.864 cm 2 s −1 . NaCl permeability selectivity ( P w /P s ) of AC-AM-97.5 is 0.208 × 10 3 , whereas pristine membrane shows 0.102 × 10 3 .

In humans, and species complexes are the leading cause of fungal meningitis globally. To establish CNS infection, must breach the BBB, primarily comprised of specialized brain microvascular endothelial cells (BMECs), which is the prerequisite for cryptococci to invade the brain. Despite its clinical impact, the mechanisms underlying host-pathogen interaction at the BBB particularly involving environmental isolates remain under-characterized. This study aimed to investigate the cyto-morphological and transcriptomic responses of HBMECs to infection by clinical and environmental isolates using a dual approach-ultrastructural electron microscopy and high-throughput dual RNA-Seq. HBMECs were infected with molecularly typed clinical and environmental isolates of and at two infection time points (4 hpi and 18 hpi). Transmission electron microscopy was used to visualize host cell ultrastructural alterations, while dual RNA-Seq was performed to assess differential gene expression in both host and pathogen. TEM revealed extensive ultrastructural changes in infected HBMECs, including membrane ruffling, increased microvilli, mitochondrial alterations, ER dilation, Golgi fragmentation, nuclear deformation, and autophagosome formation. Transcriptomic profiling demonstrated functional enrichment of several critical cryptococcal virulence-associated genes linked to immune evasion and stress adaptation including various immune signaling pathways elicited by the HBMECs as a counter measure to the cryptococcal invasion. Clinical and environmental isolates exhibit comparable invasive potential and elicit similar host endothelial responses with consistent effects observed across all isolates and time points. This integrative study combining ultrastructural and transcriptomic analyses highlights conserved host-pathogen interactions at the BBB, identifies potential molecular targets for antifungal therapy and underscores the pathogenic relevance of environmental reservoirs in cryptococcal meningitis. cryptococcal meningitis, blood-brain barrier, invasion, transmission electron microscopy, Dual RNASeq, differential gene expression, host-pathogen interaction, HBMECs, ultrastructural alterations.

Having only one type of locomotion mechanism limits the stability and locomotion capability of a mobile robot on irregular terrain surfaces. One of the possible solution to this is combining more than one locomotion mechanisms in the robot. In this paper, robotic platform composed of a quadruped module for terrain locomotion and quadrotor module for aerial locomotion is introduced. This design is inspired by the way which birds are using their wings and legs for stability in slopped and uneven surfaces. The main idea is to combine the two systems in such a way that the strengths of both subsystems are used, and the weakness of the either systems are covered. The ability of the robot to reach the target position quickly and to avoid large terrestrial obstacles by flying expands its application in various areas of search and rescue. The same platform can be used for detailed 3D mapping and aerial mapping which are very helpful in rescue operations. In particular, this paper presents kinematic design, analysis and simulation of such a robotic system. Simulation and verification of results are done using MATLAB.

Although different locomotion mechanisms are available, the use of only one locomotion system in a mobile robot restricts its application scenarios. Hybrid locomotion improves the maneuverability and flexibility of a robot. This paper introduces a hybrid locomotion mobile robot, a combination of quadruped and quadrotor system. The robot has a unique expediency to fly to remote places, then walk to perform close range operations in the field. The prime intention is to use the quadrotor to tackle large objects by flying over it. The four legs provide easy movements in uneven terrain. Thus, this robot can be used in erratic and dynamic environments where stability, maneuverability and flexibility are required. This system can be used as first responders in search and rescue missions, where it responds before human responders gets to the site and get the entire information of the area in detail (like spotting trapped ones, getting detailed 3D mapping etc.). This platform offers unique capabilities suited for search and rescue, disaster zone assistance and surveillances. This paper elucidates the mechanical design and analysis of a hybrid locomotion robot. The solid model of the robot was made using CATIA and further analysis like static analysis, computational fluid dynamics analysis and drop test analysis were performed in ANSYS.

The presence of heavy metal ions in water bodies constitutes a significant environmental hazard. The development of sustainable and cost-effective adsorbent materials for their removal is an urgent priority. In alignment with this critical objective, the present study explores the potential of a novel composite material for water remediation. This composite, fabricated from biochar and magnesium ferrite nanoparticles, targets the removal of hexavalent chromium and divalent nickel. While prior research has explored the application of rice husk as an adsorbent, no investigation, to our knowledge, has examined the potential of magnesium ferrite-rice husk composites for this purpose. Initial screening identified the biochar-magnesium ferrite composite (pre-calcination) as the most effective adsorbent. This composite displayed a superior surface area (151 m²/g) compared to calcined magnesium ferrite (91 m²/g) and achieved exceptional removal efficiencies for both chromium (50 mg/g) and nickel (54 mg/g). Optimal chromium removal occurred at pH 1 with a 110-minute contact time, while nickel favored a pH of 6 and the same contact time. The adsorption process was characterized as physisorption and endothermic. Notably, the composite exhibited efficient regeneration (82% for nickel and 90% for chromium) using simple acid/base solutions. The BJH analysis of pore characteristics indicated an average pore diameter of 1.5365 nm and a total pore volume of 0.17 cm³/g. The research findings demonstrate the composite’s effectiveness as a sustainable adsorbent for capturing heavy metal ions from water. Graphical Abstract