The interaction of pulsed plasma streams with an external magnetic field plays a crucial role in plasma physics, with direct implications for magnetic confinement fusion, astrophysical plasma dynamics, and plasma–material interactions. This study presents an experimental investigation into the penetration dynamics of a pulsed helium plasma stream across a transverse magnetic field using a pulsed plasma accelerator. High-speed imaging, optical emission spectroscopy, magnetic probes, and electric probes were employed to characterize plasma density evolution, velocity profiles, current distributions, and emission spectra. The results reveal a substantial increase in plasma density in magnetized regions, attributed to enhanced ionization processes facilitated by the magnetic field. Spectroscopic analysis based on Stark broadening of He I emission lines quantified electron density variations, showing an increase from ∼3 × 1020 m−3 at 6 kV to ∼8 × 1020 m−3 at 12 kV in the absence of an external magnetic field, and a significantly higher increase to ∼4 × 1020 m−3 at 6 kV and ∼1.5 × 1021 m−3 at 12 kV under an external transverse magnetic field. The emission spectra further revealed impurity lines due to electrode erosion, with increased spectral broadening in the magnetized plasma, indicating stronger electron-density gradients and plasma compression. Magnetic probe measurements mapped the spatial distribution of the electric current and Ampère forces, revealing current vortices and the formation of compression zones in the presence of an external magnetic field. Electric probe measurements demonstrated a marked deceleration of plasma velocity under magnetized conditions, ascribed to Lorentz force-driven charge redistribution and induced polarization effects. The presence of the external magnetic field also led to the formation of magneto-Rayleigh–Taylor instability-induced fingerlike structures, altering plasma flow dynamics. These findings provide critical insights into plasma transport mechanisms in the magnetized region, with direct applications to magnetic confinement fusion, magnetized plasma propulsion, and laboratory astrophysics.
The current study provides a comprehensive analysis of MHD hybrid nanofluids and stagnation point flow toward a porous stretched cylinder in the presence of thermal radiation. Here, alumina and copper are considered the hybrid nanoparticles, while water is the base fluid. To begin, the required similarity transformations are applied to transform the nonlinear coupled PDEs into nonlinear coupled ODEs. The obtained highly nonlinear sets of ODEs are then solved analytically by using the HAM procedure. The calculations of the thermal radiation term in the energy equation are done based on the Roseland approximation. The result of various embedded variables on temperature and velocity profiles is drawn and explained briefly. Aside from that, the numerical solution of well-known physical quantities, like skin frictions and the Nusselt number, is computed by means of tables for the modification of the relevant parameter. The analysis shows that the magnetic field has opposite behavior on and profiles. It is seen that more magnetic factor M decline and upsurge . Moreover, the behavior of skin friction and the Nusselt number are same for the magnetic parameter M. Meanwhile, a higher Reynolds number declines temperature profile and skin friction while upsurge the local Nusselt number. There are many applications of this study that are not limited to engineering and manufacturing, such as polymer industry, crystal growth, tumor therapy, plasma, fusing metal in electric heaters, nuclear reactors, asthma treatment, gastric medication, cooling of atomic systems, electrolytic biomedicine, helical coil heat exchangers, axial fan design, polymer industry, plane counter jets, and solar collectors.
Drought alone causes more annual loss in crop yield than the sum of all other environmental stresses. There is growing interest in harnessing the potential of stress-resilient PGPR in conferring plant resistance and enhancing crop productivity in drought-affected agroecosystems. A detailed understanding of the complex physiological and biochemical responses will open up the avenues to stress adaptation mechanisms of PGPR communities under drought. It will pave the way for rhizosphere engineering through metabolically engineered PGPR. Therefore, to reveal the physiological and metabolic networks in response to drought-mediated osmotic stress, we performed biochemical analyses and applied untargeted metabolomics to investigate the stress adaptation mechanisms of a PGPR Enterobacter bugendensis WRS7 (Eb WRS7). Drought caused oxidative stress and resulted in slower growth rates in Eb WRS7. However, Eb WRS7 could tolerate drought stress and did not show changes in cell morphology under stress conditions. Overproduction of ROS caused lipid peroxidation (increment in MDA) and eventually activated antioxidant systems and cell signalling cascades, which led to the accumulation of ions (Na+, K+, and Ca2+), osmolytes (proline, exopolysaccharides, betaine, and trehalose), and modulated lipid dynamics of the plasma membranes for osmosensing and osmoregulation, suggesting an osmotic stress adaption mechanism in PGPR Eb WRS7. Finally, GC-MS-based metabolite profiling and deregulated metabolic responses highlighted the role of osmolytes, ions, and intracellular metabolites in regulating Eb WRS7 metabolism. Our results suggest that understanding the role of metabolites and metabolic pathways can be exploited for future metabolic engineering of PGPR and developing bio inoculants for plant growth promotion under drought-affected agroecosystems.
Abstract Advances in high-performance computing now enable the engineering evaluation of large blanket components from a systems perspective at the beginning of a normal design cycle. As an example, we discuss the computational fluid dynamics (CFD) involved in characterizing the thermal performance of an entire 22.5 toroidal sector of a dual-coolant lead-lithium blanket with particular attention to the integrated manifolding and flow distributions. The inboard sector is roughly 7 m tall, has 321 first-wall helium-cooled channels, and five parallel PbLi breeder channels complete with insulating SiC flow channel inserts. A finite volume model was developed with various degrees of mesh refinement from 36 to 187 million cells to perform the flow calculations on disparate fluids with conjugate heat transfer in the solid. Steady-state CFD calculations were performed using a realizable k-ε turbulence model. Simplifications include a uniform applied surface heat flux and a one-dimensional radial volumetric neutron heating profile. Constant material properties were used for the F82H reduced-activation ferritic martensitic (RAFM) steel walls, SiC flow channel inserts, and the PbLi breeder. Ideal gas behavior was assumed for the helium, which includes compressibility. Helium mass flows of 54 kg/s at 8 MPa and PbLi flows of 3 kg/s at 101 kPa supply the sector, both at an inlet temperature of 350°C. This early model is not optimized; however, it reveals important features not obvious in a conglomeration of smaller independent models. For example, all the manifolding was included to evaluate flow distributions throughout the full component. Submodels were only used to obtain the convective heat transfer coefficients (HTCs) inside the helium first-wall channels equipped with enhancement vanes that allow the first wall to handle 0.8 MW/m2 of plasma heat flux with the aim of keeping bulk RAFM steel temperatures near the creep-fatigue limit of 550°C. Average HTCs obtained from these detailed submodels were then used in the large model to predict thermal performance without incurring the meshing overhead from the thousands of internal vanes. Although much progress was made, initial results indicate that more must be done to further reduce hot spots on the first wall, minimize pressure drops, and provide optimal flow distributions.
Atmospheric pressure plasma jet can generate a remote plasma plume, which usually presents a conical or cylindrical morphology. Despite a few morphologies have been observed, efforts should be attempted to obtain more plume structures because streamer dynamics may be revealed from them. Aim to this purpose, an argon plasma plume excited by a trapezoidal voltage is investigated, which presents two kinds of swells (a hollow swell and a diffuse swell) with increasing voltage amplitude (Vp). Results indicate that there are two positive discharges (Dp1 and Dp2) and one negative discharge (Dn) per voltage cycle for both of the swells. With increasing Vp, inception voltage and discharge intensity increase for every positive discharge, while decrease for the negative discharge. Fast photography reveals that the positive streamer (Dp2) leaves different tracks in the two swells, which are curved in the hollow swell and randomly branched in the diffuse swell. The different tracks of Dp2 are explained through considering applied field strength and residual positive ions of Dp1. The existence of residual positive ions is verified from optical emission spectra at last.
The Sawada-Kotera equations illustrate the non-linear wave phenomena in shallow water, ion-acoustic waves in plasmas, fluid dynamics, etc. In this article, the two-mode Sawada-Kotera equation (tmSKE) occurring in fluid dynamics is considered which is important model equations for shallow water waves, the capillary waves, the waves of foam density, the electro-hydro-dynamical model. The improved F-expansion and generalized exp $(-\phi (\zeta))$ -expansion methods are utilized in this model and abundant of solitary wave solutions of different kinds such as bright and dark solitons, multi-peak soliton, breather type waves, periodic solutions, and other wave results are obtained. These achieved novel solitary and other wave results have significant applications in fluid dynamics, applied sciences and engineering. By granting appropriate values to parameters, the structures of few results are presented in which many structures are novel. The graphical moments of the results are provided to signify the impact of the parameters. To explain the novelty between the present results and the previously attained results, a comparative study has been carried out. The restricted conditions are also added on solutions to avoid singularities. Furthermore, the executed techniques can be employed for further studies to explain the realistic phenomena arising in fluid dynamics correlated with any physical and engineering problems.
Biomimetics is a design principle within chemistry, biology, and engineering, but chemistry biomimetic approaches have been generally limited to emulating nature’s chemical toolkit while emulation of nature’s physical toolkit has remained largely unexplored. To begin to explore this, we designed biophysically mimetic microfluidic reactors with characteristic length scales and shear stresses observed within capillaries. We modeled the effect of shear with molecular dynamics studies and showed that this induces specific normally buried residues to become solvent accessible. We then showed using kinetics experiments that rates of reaction of these specific residues in fact increase in a shear-dependent fashion. We applied our results in the creation of a new microfluidic approach for the multidimensional study of cysteine biomarkers. Finally, we used our approach to establish dissociation of the therapeutic antibody trastuzumab in a reducing environment. Our results have implications for the efficacy of existing therapeutic antibodies in blood plasma as well as suggesting in general that biophysically mimetic chemistry is exploited in biology and should be explored as a research area.
Polymers that are biocompatible and degradable are desired for tissue engineering approaches in the treatment of vascular diseases, especially for those involving small-diameter blood vessels. Herein, we report the compatibility of a newly developed glycerol-based aliphatic polycarbonate possessing simple methoxy side groups, named poly(5-methoxy-1,3-dioxan-2-one) (PMDO), with blood cells and plasma proteins as well as its susceptibility to hydrolysis. As a consequence of the organocatalytic ring-opening polymerization (ROP) of a methoxy-functionalized cyclic carbonate derived from glycerol, PMDO with a sufficiently high molecular weight (Mn 14 kg/mol) and a narrow distribution (D̵M 1.12) was obtained for evaluation as a bulk biomaterial. This study demonstrates for the first time the organocatalytic ROP of a glycerol-based cyclic carbonate in a controlled manner. Compared with the clinically applied aliphatic polycarbonate poly(trimethylene carbonate) (PTMC), PMDO inhibits platelet adhesion by 33% and denaturation of fibrinogen by 23%. Although the wettability of PMDO based on water contact angle was almost comparable to those of PTMC and poly(ethylene terephthalate), the reason for the inhibited platelet adhesion and protein denaturation appeared to be related to the presence of specific hydrated water formed in the hydrated polymer. The improved hydration of PMDO also enhanced the susceptibility to hydrolysis, with PMDO demonstrating a slightly higher hydrolytic property than PTMC. This simple glycerol-based aliphatic polycarbonate has the following benefits: bio-based characteristics of glycerol and improved blood compatibility and hydrolytic biodegradability stemming from moderate hydration of the methoxy side groups.
Abstract Tungsten (W) or W alloys are the main candidates for plasma-facing materials of future fusion reactors. Large-sized W-Y2O3 bulk material has been successfully produced in this study for future engineering applications. Wet chemical method and continuous hydrogen (H2) reduction were applied to achieve mass preparation of W-Y2O3 composite powder. The final bulk material was obtained using the H2 atmosphere sintering technique and rolling deformation process. Conventional X-ray diffraction patterns were used to characterize the different surfaces of the rolled specimen, which coincide with the results of electron backscatter diffraction detection, to evaluate the texture information. The 50% rolled W-Y2O3 bulk material have three types of textures, namely, θ-fiber, α-fiber, and γ-fiber. Notably, the thermal conductivity exhibits no obvious difference between sintered bulk at the original state and rolled bulk along various directions. After rolling deformation of the W-Y2O3 bulk material, the effect of the anisotropic microstructure on the thermal conductivity can be offset by the effect of the fiber geometric structure. For the body-centered cubic structure of W, the thermal conductivity versus the crystal orientation should be λ[100] > λ[110].