Enhancement Of Density Research Articles

VLT VIMOS integral field spectroscopy of the nova remnant FH Ser

The source FH,Ser experienced a slow classical nova outburst in February 1970 that was the first ever observed at UV, optical, and IR wavelengths. Its nova remnant is elliptical and has multiple knots. A peculiar ring-like filament lies along its minor axis. We investigate here the true 3D spatio-kinematical structure of FH,Ser to assess the effects of early shaping and to assess its mass and kinetic energy. We obtained integral field spectroscopic observations made with the Very Large Telescope (VLT) VIsible MultiObject Spectrograph (VIMOS) of FH,Ser. The data cube was analyzed using 3D visualizations that revealed different structural components. A simple geometrical model was compared to the 3D data cube to determine the spatio-kinematic properties of FH,Ser. FH,Ser consists of a tilted prolate ellipsoidal shell that is most prominent in Hα, and of a ring-like structure that is most prominent in N ii . The ellipsoidal shell has equatorial and polar velocities of ≃505 and ≈630 km s^-1, respectively, and its major axis is tilted by ≃52^∘ with respect to the line of sight. The inclination angle of the symmetry axis of the ring is similar, that is, it can be described as an equatorial belt of the main ellipsoidal shell. FH,Ser has an ionized mass of 2.6 M_⊙, with a kinetic energy of 1.6 erg. The two different structural components in FH,Ser with a similar orientation can be linked to a density enhancement along a plane, most likely the orbital plane at the time of the nova event. The acquisition of integral field spectroscopic observations of nova remnants is mostly required to separate different structural components and to assess their 3D physical structure.

Renewable Energy Through Soil Segmented Bio-Batteries

The increasing global demand for energy and the environmental challenges posed by fossil fuels necessitate the exploration of alternative, renewable energy sources. Soil-based bio-batteries offer a sustainable solution by converting organic matter into electricity. This study introduces segmented bio-batteries, which integrate multiple microbial cells in series or parallel, improving power density and scalability. Manure from cattle, birds, and sheep is used as an organic substrate to enhance microbial activity, optimizing energy output. Experimental results demonstrate the effectiveness of segmented bio-batteries in generating electricity, recycling agricultural waste, and reducing carbon footprints, making them viable for rural electrification and environmental sustainability. Keywords—Microbial fuel cells (MFCs), Segmented bio-batteries, Renewable energy, Power density enhancement, Agricultural applications, Soil-based energy systems, Sustainable energy, Waste-to-energy conversion, Eco-friendly power generation, Rural electrification

Boosting Energy Harvesting Performance in Piezoelectric Composites with Aligned Porosity via a Dual Structure Design Strategy.

Porous piezoelectric materials have attracted much interest in the fields of sensing and energy harvesting owing to their low dielectric constant, high piezoelectric voltage coefficient, and energy harvesting figure of merit. However, the introduction of porosity can decrease the piezoelectric coefficient, which restricts the enhancement of output current and power density. Herein, to overcome these challenges, an array-structured piezoelectric composite energy harvester with aligned porosity was constructed via a dual structure design strategy to enhance the output current and power density. Silver metal particles were introduced into a porous barium calcium zirconate titanate (BCZT) ceramic matrix as a secondary phase to regulate the dielectric, ferroelectric, and piezoelectric properties. The optimal addition of silver particles can reduce the size of ferroelectric domains, which leads to an enhanced piezoelectric coefficient and energy harvesting figure of merit. Combined with the design of the array structure, the maximum output voltage and current of the piezoelectric composite energy harvester can reach 76 V and 340 μA, respectively, with a peak power density of 0.97 mW/cm2. Furthermore, the array-structured piezoelectric energy harvester can light 40 blue LED bulbs and power commercial low-power electronic devices. This work provides a strategy to boost the output current and power density of porous piezoelectric materials via a micro-macro structure design strategy for energy harvesting applications.

Precise Regulation of In Situ Exsolution Components of Nanoparticles for Constructing Active Interfaces toward Carbon Dioxide Reduction.

Metal nanocatalysts supported on oxide scaffolds have been widely used in energy storage and conversion reactions. So far, the main research is still focused on the growth, density, size, and activity enhancement of exsolved nanoparticles (NPs). However, the lack of precise regulation of the type and composition of NPs elements under reduction conditions has restricted the architectural development of in situ exsolution systems. Herein, we propose a strategy to attain a regulated distribution of exsolved transition metals (Cu, Ni, and Fe) on Sr2Fe1.2Ni0.2Cu0.2Mo0.4O6-δ medium-entropy perovskite oxides by varying the oxygen partial pressure (pO2) gradient in the mixture. At 800 °C, the unitary Cu, binary Cu-Ni, and ternary Cu-Ni-Fe NPs are exsolved as pO2 decreases from high to low. Combining experimental and theoretical simulations, we further corroborate that solid oxide electrolysis cells with ternary alloy clusters at the CNF@SFO interface exhibit superior CO2 electrolytic performance. Our results provide tailored strategies for nanostructures and nanointerfaces for studying metal oxide exsolution systems, including fuel electrode materials.

Mitochondrial transplantation reconstructs the oxidative microenvironment within fibroblasts to reverse photoaging.

Fibroblast-mediated oxidative stress is a pivotal factor in the pathogenesis of skin photoaging, predominantly induced by UVA radiation. Diverging from traditional strategies that concentrate on the reduction of reactive oxygen species (ROS), the present study implements mitochondrial transplantation as an innovative therapeutic approach. The objective of this study is to reestablish the oxidative microenvironment and to effectively rejuvenate cellular functionality through the direct introduction of healthy and vibrant mitochondria. In vitro assays have illustrated that the seamless incorporation of exogenous mitochondria into fibroblasts ameliorates UVA radiation perturbations in membrane potential and oxidative stress, while simultaneously reestablishing the oxidative microenvironment. These interventions exert salutary influences on cellular proliferation and migratory capabilities. Subsequent in vivo analyses reveal a mitigation in dermal collagen depletion, alongside an enhancement in collagen fiber density and tissue architecture post-mitochondrial transplantation, thus ameliorating the manifestations of skin photoaging. Collectively, the study underscores the potential of mitochondrial transplantation as a promising therapeutic intervention for the reversal of skin photoaging by modulating the oxidative microenvironment within fibroblasts.

Enhancement of critical current density in Mg incorporated ex-situ MgB2 via co-addition of B4C and Dy2O3

Enhancement of critical current density in Mg incorporated ex-situ MgB2 via co-addition of B4C and Dy2O3

Facet engineering of Cu2O for efficient electrochemical glucose sensing.

Accurate monitoring glucose level is significant for human health management, especially in the prevention, diagnosis, and management of diabetes. Electrochemical quantification of glucose is a convenient and rapid detection method, and the crucial aspect in achieving great sensing performance lies in the selection and design of the electrode material. Among them, Cu2O, with highly catalysis ability, is commonly used as electrocatalyst in non-enzymatic glucose sensing. This feature has attracted great attentions for improving sensing performances by increasing exposed surface area and modifying with other active materials, but the intrinsic electrochemical activity of Cu2O is often diminished. In this work, we synthesized Cu2O cubes with exposed (100) faces, Cu2O octahedron with exposed (111) faces and Cu2O rhombic dodecahedron with exposed (110) faces of similar sizes to investigate the influence of expose facets on its glucose sensing performance. By employing the facets-regulation strategy, the anti-interference performance was largely improved by the Cu2O octahedron when compared with the Cu2O cube and the Cu2O rhombic dodecahedron, while the sensitivity and stability were also improved. Eventually, the Cu2O octahedron with exposed (111) faces based on glucose sensor displayed great practicability in human serum and the relative deviation was less than 3 % when compared with biochemical analyzer. Experimental, calculation and simulation result elucidate that Cu2O octahedron with exposed (111) faces, possessing stronger intrinsic electrochemical activity, comparatively favors the glucose adsorption, electron transfer and current density enhancement, rather than more active sites. This work focuses on the exploration of the intrinsic electrochemical activity of Cu2O and confirms that a facets-regulation strategy is an effective approach for boosting performance of non-enzymatic electrochemical sensors, especially for their sensitivity and selectivity. Moreover, it will lay the foundation for advancing the key field of precision medicine.

Developing High Energy Density Li-S Batteries via Pore-Structure Regulation of Porous Carbon Based Electrocatalyst.

The mesopores and macropores within porous carbon materials help increasethe surface for the depostion of solid-state products, reducethe Li2S film thickness, enhanceelectron and mass transport, and accelerate the reaction kinetics. However, an excessive amount of mesopores and macropores can lead to increased electrolyte consumption, particularly at high sulfur loadings, where excessive electrolyte usage hampers the enhancement of practical energy density in lithium-sulfur (Li-S) batteries. A rational pore structure can minimize the amount of electrolyte to fill the pores, thereby reducing electrolyte consumption while achieving rapid reaction kinetics and a high gravimetric energy density. In this work, the pore structure of carbon nanosheet-based electrocatalysts is precisely controlled by adjusting the content of a water-soluble potassium chloride template, allowing for in-depth investigation of the relationship between pore structure, electrolyte usage, and electrochemical performance in Li-S batteries. The molybdenum carbide-embedded carbon nanosheet (MoC-CNS) electrocatalyst, with an optimized pore structure, facilitates exceptional electrochemical performance under high sulfur loading and lean electrolyte conditions. Ultimately, the MoC-CNS-3-based Li-S battery achieved stable operation over 50 cycles under high sulfur loading (12mgcm-2) and a low electrolyte-to-sulfur (E/S) ratio of 4uLmg-1, delivering a high gravimetric energy density of 354.5Whkg-1. This work provides a viable strategy for developing high-performance Li-S batteries.

Global Distribution of Ionospheric Topside Diffusive Flux and Midlatitude Electron Density Enhancement in Winter Nighttime

AbstractIonospheric topside diffusive flux is derived using Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation data, to investigate its global distribution and also its role in winter nighttime enhancement (WNE) of electron density. The flux of the winter hemisphere maintains downward throughout the night. It is much larger between and geomagnetic latitudes and keeps increasing until 22:00–00:00 LT. It peaks at W and E–E geographic longitudes during the December solstice, and at E during the June solstice. These features are similar to those of WNE in NmF2. Furthermore, the derived flux is applied as the upper boundary condition to run the Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM). The simulated spatial‐temporal variations of WNE are consistent with the observations. The results indicate that downward plasma diffusion from the plasmasphere is the major mechanism of WNE, and the simulation quantifies its contribution.

A Low-Cost 3D Mapping System for Indoor Scenes Based on 2D LiDAR and Monocular Cameras

The cost of indoor mapping methods based on three-dimensional (3D) LiDAR can be relatively high, and they lack environmental color information, thereby limiting their application scenarios. This study presents an innovative, low-cost, omnidirectional 3D color LiDAR mapping system for indoor environments. The system consists of two two-dimensional (2D) LiDARs, six monocular cameras, and a servo motor. The point clouds are fused with imagery using a pixel-spatial dual-constrained depth gradient adaptive regularization (PS-DGAR) algorithm to produce dense 3D color point clouds. During fusion, the point cloud is reconstructed inversely based on the predicted pixel depth values, compensating for areas of sparse spatial features. For indoor scene reconstruction, a globally consistent alignment algorithm based on particle filter and iterative closest point (PF-ICP) is proposed, which incorporates adjacent frame registration and global pose optimization to reduce mapping errors. Experimental results demonstrate that the proposed density enhancement method achieves an average error of 1.5 cm, significantly improving the density and geometric integrity of sparse point clouds. The registration algorithm achieves a root mean square error (RMSE) of 0.0217 and a runtime of less than 4 s, both of which outperform traditional iterative closest point (ICP) variants. Furthermore, the proposed low-cost omnidirectional 3D color LiDAR mapping system demonstrates superior measurement accuracy in indoor environments.

Therapeutic potential of farnesoid X receptor agonists for modulating inflammation and periodontal regeneration.

Inflammation and osteoclast activity are important in various diseases, including periodontitis and osteoporosis. Farnesoid X receptor (FXR) has been identified as a promising target for modulating these processes. This study delved into the impact of FXR agonists on inflammation and periodontal regeneration using periodontitis models. The RAW264.7 and gingival fibroblast cells were divided into five groups: control, lipopolysaccharide (LPS), LPS combined with FXR agonist, LPS with si-FXR, and LPS with si-FXR alongside FXR agonist. FXR expression and pro-inflammatory cytokine levels were quantified. Osteoclast activity was evaluated by observing morphological alterations and tartrate-resistant acid phosphatase staining. The rats were used to establish periodontitis models and received varying doses of FXR agonist. Bone health metrics were assessed, and the expressions of runt-related transcription factor 2 (RUNX2), integrin-binding sialoprotein (IBSP), nuclear factor-kappa B (NF-kB), phosphorylated nuclear factor-kappa B (p-NF-kB), toll-like receptor 4 (TLR4), and toll-like receptor 2 (TLR2) were determined. FXR suppressed the release of pro-inflammatory cytokines in both LPS-stimulated RAW264.7 and gingival fibroblast cells, while curbing osteoclastogenesis. In periodontitis rat models, FXR agonist administration caused notable enhancement in bone density. Moreover, FXR agonist mitigated periodontal inflammation, decreased periodontal index markers and suppressed the expressions of NF-kB, p-NF-kB, TLR4, and TLR2, but upregulated the expressions of RUNX2 and IBSP. The data underscores the potential of FXR agonists in attenuating inflammation and periodontal regeneration, both in vitro and in vivo. This suggests the potential therapeutic application of FXR agonists in conditions marked by inflammation and bone degradation.

Organoclay flocculation as a pathway to export carbon from the sea surface

Marine microorganisms play a critical role in regulating atmospheric CO2 concentration via the biological carbon pump. Deposition of continental mineral dust on the sea surface increases carbon sequestration but the interaction between minerals and marine microorganisms is not well understood. We discovered that the interaction of clay minerals with dissolved organic matter and a γ-proteobacterium in seawater increases Transparent Exopolymer Particle (TEP) concentration, leading to organoclay floc formation. To explore this observation further, we conducted a microcosm experiment using surface seawater collected from the Spring 2023 phytoplankton bloom in the Gulf of Maine. Unfiltered (natural community) and filtered (200 μm and 3 μm) seawater was sprayed with clay (20 mg L− 1 and 60 mg L− 1) and incubated. All clay treatments led to a tenfold increase in TEP concentration. 16S rRNA gene amplicon sequence analyses of seawater and settled organoclay flocs showed the dominance of α-proteobacteria, γ-proteobacteria, and Bacteroidota. The initial seawater phytoplankton community was dominated by dinoflagellates followed by a haptophyte (Phaeocystis sp.) and diatoms. Following clay addition, dinoflagellate cell abundance declined sharply while diatom cell abundance increased. By analyzing organoclay flocs for 18S rRNA we confirmed that dinoflagellates were removed in the flocs. The clay amendment removed as much as 50% of phytoplankton organic carbon. We then explored the fate of organoclay flocs at the next trophic level by feeding clay and phytoplankton (Rhodomonas salina) to Calanus finmarchicus. The copepod ingested R. salina and organoclay flocs and egested denser fecal pellets with 1.8- to 3.6- fold higher sinking velocity compared to controls. Fecal pellet density enhancement could facilitate carbon sequestration through zooplankton diel vertical migration. These findings provide insights into how atmospheric dust-derived clay minerals interact with marine microorganisms to enhance the biological carbon pump, facilitating the burial of organic carbon at depths where it is less likely to exchange with the atmosphere.

Composition-Graded Nitride Ferroelectrics Based Multi-Level Non-Volatile Memory for Neuromorphic Computing.

Multi-level non-volatile ferroelectric memories are emerging as promising candidates for data storage and neuromorphic computing applications, due to the enhancement of storage density and the reduction of energy and space consumption. Traditional multi-level operations are achieved by utilizing intermediary polarization states, which exhibit an unpredictable ferroelectric domain switching nature, leading to unstable multi-level memory. In this study, a unique approach of composition-graded ferroelectric ScAlN to achieve tunable operating voltage in a wide range and attain precise control of domain switching and stable multi-level memory is proposed. This non-volatile memory supports multi-level storage up to 7-bit capacities, and exhibits enhanced performance compared to the uniform composition device, showing one order of magnitude higher ON/OFF ratio, 30% reduced working voltage, and up to 50% enhanced tuning window of operating voltage. Finally, the emulation of long-term plasticity and linear weight update akin to biological synapse with high uniformity and reliability are demonstrated. The proposed composition-grading architecture offers new opportunities for next-generation multi-level ferroelectric memories, paving the way for advanced hybrid integration in multifunctional computing systems.

Net-shaping (Y,NSG)BCO composite superconductor into cylindrical geometry with enhanced flux pinning up to 9 T at 77 K

Abstract Fabrication of a (Y,RE)BCO superconducting compact simultaneous with improved properties is demonstrated using gelcasting of slurries into rapid prototyped precision moulds. The infiltration Growth (IG) process with NdBCO film seed was used to obtain a textured 45 mm long hollow superconducting (Y,RE)BCO cylinder, as a prototype. This involves design of a (Y,RE)2BaCuO5 preform referred to as (Y,RE)-211, into which liquid phase is infiltrated; this reacts with the preform and forms (Y,RE)Ba2Cu3O7-x. The end product aimed at is a composite of YBa2Cu3O7-x (YBCO) with 20 wt% of mixed rare earth (Nd,Sm,Gd)BCO and 0.5 wt% of WO3 nanoparticles, which are intended to cause notable enhancement in flux pinning and critical current density (J c). Uniform distribution of micron-sized (Y/RE)-211 and WO3 nanoparticles in the matrix was enabled by sol-casting process. Magnetic shielding is demonstrated at low dc fields (41 gauss). J c is found to remain nearly constant with field (B) at each temperature (T) up to 50 K, where J c reaches about 4 kA cm−2 at 8.5 T. At 77 K, J c of ∼ 4 kA cm−2 at zero field and ∼ 0.4 kA cm−2 at 8.5 T is observed. The flux pinning force density (F p) increased with the applied field, reaching a maximum at a field (B p) of 7 T to 8 T for all temperatures from 10 K to 77 K. Temperature-independent B p confirms that flux pinning is caused by structural defects that induce fluctuations in the Ginzberg-Landau parameter (k). Substitution of RE ions randomly at the Y-site in YBCO unit cells can locally create compositional fluctuations that lead to stress fields and a dense network of stacking faults and assist pinning of flux. Analysis of F p (B) by scaling laws does confirm δk pinning to be the dominant mechanism. A second peak observed in F p(B) curves at low fields, below 3 T, is attributed to additional pinning from WO3 nanoparticles and is field-dependent. Significance of the present process stems from the fact that it enables uniform distribution of second phase additions to be realized in the end product, for improved performance and it allows design and creation of components of composite ceramic superconductor in any complex shape, required for a chosen application.

Boiling performance enhancement and self-recovery of nucleate boiling regime on micro- and nanostructured porous surfaces

In this paper, we report the pool boiling experimental results for significant enhancements in the boiling heat transfer coefficient (BHTC) and CHF on various microporous surfaces. The microporous surfaces were fabricated by metal (Copper) powder sintering process, and nanostructured porous surfaces were additionally fabricated through the thermal oxidation of the metal porous surfaces. Among the examined substrates, a boiling surface with a thin metal porous layer and millimeter-sized porous pillar structures exhibited optimal boiling performance; the BHTC and CHF of the microporous surface were measured to be approximately 500 % and 270 % higher than those of a smooth reference surface, respectively. We conjecture that the results come from the combined effect of active nucleation site density enhancement, capillary wicking promotion, and separation of liquid-vapor flow paths on the microporous surface with porous pillars. On the other hands, the porous pillar surface with needle-like nanostructures showed the interesting phenomena that can be regarded to the recovery of the boiling regime from transition boiling to nucleate boiling. At the CHF, the temperature increase on the surface was slower than that on the other surfaces. Additionally, at high heat fluxes below the CHF, the overheated surface self-recovered to the nucleate boiling state, indicating the rewetting of local dry spots. We consider that the capillary wicking capability strongly improved by the nanostructures on the surface was presumably responsible for inhibiting the irreversible expansion of local dry spots. From the experimental observations throughout this study, we propose the following key requirements to design an ideal boiling surface: increasing the nucleation site density, ensuring a liquid supply path by capillary wicking, separating the liquid and vapor flow paths, and improving the liquid wettability of the solid surface by forming nanostructures.

Stress relief annealing of super Invar alloy: microstructure, soft magnetic and thermal expansion properties

Invar (Fe64Ni36) alloy is regarded as a prospective contender for thermal structural materials and transformers utilized in aerospace vehicles, in addition to electrical, and other applications, largely due to its markedly low expansion properties. It is noteworthy that the optimization of permeability and coercivity in Invar alloys has the potential to meet the requirements of a broader range of applications. Consequently, enhancing the soft magnetic properties and extending the low expansion intervals is crucial. The effects of stress relief annealing on the microstructure, soft magnetic properties, and thermal expansion behavior of super Invar alloy (Fe64Ni32Co4) are investigated. The findings indicate that the incorporation of Co has no impact on the phase structure of the Fe-Ni alloy, yet elevates the Curie temperature of the Fe-Ni alloy to 324.84°C. As the annealing temperature is increased, the grain diameter of the alloy increases gradually. Concurrently, the enhancement of density and magnetocrystalline isotropy diminishes the prevalence of lattice defects, which markedly influences the soft magnetic characteristics of super Invar alloy. At an annealing temperature of 1150°C, the material exhibits a saturation magnetic flux density of 1494 mT, a maximum permeability of 31.04mH/m, a coercivity of 13.52A/m, and a wide low expansion interval. This phenomenon can be attributed to random orientation, residual stress relief, and higher Curie temperatures. The results provide a comprehensive insight into the evolution of soft magnetic properties and their underlying mechanisms, covering a larger range of low expansion intervals.

PNb9O25-Li4Ti5O12 blended anode with enhanced capacity and volumetric energy density

Lithium titanate (Li4Ti5O12, LTO) used as a “zero-strain” anode material in lithium-ion batteries (LIBs) is well-known for its long cycle life. However, its practical application is limited due to the low specific capacity (170 mAh/g). In this research, we optimized the electrode composition by incorporating micrometer-sized phosphorus niobium oxides (PNb9O25, PNO) to prepare blended anode electrode, thereby significantly improving the capacity, stability, and volumetric energy density. PNO serves as a mixed ionic and electronic conductor (MIECs), aiding in the reduction of polarization and enhancement of the tap density. Consequently, the LTO/PNO (20 %) blended anode with 90 % active material content are able to stably deliver 93 % capacity retention at 4000 mA g−1 after 4000 cycles and high volumetric energy density of 668 Wh L–1. Our findings underscore the significance of industrialization methods, emphasizing the need for targeted modifications to enhance cell performance.

High-resolution observations of 12CO and 13CO J = 3 → 2 towards the NGC 6334 extended filament

NGC 6334 is a giant molecular cloud (GMC) complex that exhibits elongated filamentary structure and harbours numerous OB-stars, H II regions, and star-forming clumps. To study the emission morphology and velocity structure of the gas in the extended NGC 6334 region using high-resolution molecular line data, we made observations of the 12CO and 13CO J = 3 → 2 lines with the LAsMA instrument at the APEX telescope. The LAsMA data provided a spatial resolution of 20″ (~0.16 pc) and sensitivity of 0.4 K at a spectral resolution of 0.25 km s−1. Our observations revealed that gas in the extended NGC 6334 region exhibits connected velocity coherent structure over ~80 pc parallel to the Galactic plane. The NGC 6334 complex has its main velocity component at approximately −3.9 km s−1 with two connected velocity structures at velocities approximately −9.2 km s−1 (the ‘bridge’ features) and −20 km s−1 (the northern filament, NGC 6334-NF). We observed local velocity fluctuations at smaller spatial scales along the filament that are likely tracing local density enhancement and infall, while the broader V-shaped velocity fluctuations observed towards the NGC 6334 central ridge and G352.1 region located in the eastern filament EF1 indicate globally collapsing gas onto the filament. We investigated the 13CO emission and velocity structure around 42 WISE H II regions located in the extended NGC 6334 region and found that most H II regions show signs of molecular gas dispersal from the centre (36 of 42) and intensity enhancement at their outer radii (34 of 42). Furthermore most H II regions (26 of 42) are associated with least one ATLASGAL clump within or just outside of their radii, the formation of which may have been triggered by H II bubble expansion. Typically towards larger H II regions we found visually clear signatures of bubble shells emanating from the filamentary structure. Overall the NGC 6334 filamentary complex exhibits sequential star formation from west to east. Located in the west, the GM-24 region exhibits bubbles within bubbles and is at a relatively evolved stage of star formation. The NGC 6334 central ridge is undergoing global gas infall and exhibits two gas bridge features possibly connected to the cloud-cloud collision scenario of the NGC 6334-NF and the NGC 6334 main gas component. The relatively quiescent eastern filament (EF1 - G352.1) is a hub-filament in formation, which shows the kinematic signature of global gas infall onto the filament. Our observations highlight the important role of H II regions in shaping the molecular gas emission and velocity structure as well as the overall evolution of the molecular filaments in the NGC 6334 complex.

Dynamic characteristics of pumped thermal-liquid air energy storage system: Modeling, analysis, and optimization

Pumped thermal-liquid air energy storage (PTLAES) is a novel energy storage technology that combines pumped thermal- and liquid air energy storage and eliminates the need for cold storage. However, existing studies on this system are all based on steady-state assumption, lacking dynamic analysis and optimization to better understand the system’s performance under cyclic operation. To fill this gap, the mainbody-linearized cyclic dynamic model of the PTLAES system with packed bed thermal energy storage (TES) was first developed. Then, the dynamic characteristics of the baseline system were investigated. Sensitivity analyses were carried out on TES parameters. Minimal values of levelized cost of storage (LCOS) were observed for all parameters in the range of interest. Subsequently, the TES circuit was optimized, and a triple improvement of efficiency and energy density enhancement, discharge stabilization, and cost reduction was achieved. The optimized system's round-trip efficiency and energy density increased from 61.7% to 63.1% and from 141.9 kWh/m³ to 159.2 kWh/m³, and the LCOS decreased from 163.2 $/MWh to 159.4 $/MWh. A power offset ratio lower than 3% was reached, which is the lowest value ever reported in the literature. This study provides reference for future design and operation of the PTLAES system.

Mechanism of biochar-Cu-based catalysts construction and its electrochemical CO2 reduction performance

Electrochemical CO2 reduction can convert CO2 into high-value-added products for special forms of energy storage and efficient carbon utilization for renewable electricity. To investigate the influence of biochar-Cu-based catalysts properties on electrochemical CO2 reduction performance, Cu is loaded onto rice husk-based biochar by impregnation method combined with pyrolysis and calcination in this study. The three synthesized biochar-Cu-based catalysts are tested for activity and electrochemical CO2 reduction performance in Flow Cell. The results show that biochar's properties, such as its high specific surface area, rich pore structure, and adjustable pore structure, provide sufficient sites for CO2 reduction. Urea can relatively increase the copper loading by 44 %, but it will also increase the clustering of copper. In the reduction performance test, the current density of char-Cu-700 is 2.08 times higher than that of char-Cu and 1.45 times higher than char-Cu-N at a reduction potential of -0.45 (V vs. RHE). The current density enhancement of the catalyst loaded on biochar with Cu particle size of 10 nm is about 50 % higher than that of the catalyst with a particle size of 20 nm. It indicates that the smaller the particle size of Cu at the nanoscale, the lower the average coordination of surface atoms and the greater the catalyst's reactivity. This study provides novel ideas for synthesizing biochar-Cu-based catalysts, lays part of the theoretical foundation for using biochar-Cu-based catalysts for electrochemical CO2 reduction, and provides experimental support for optimizing the catalyst structure.