Maximum Density Research Articles

Biological effects of culture medium on Tetraselmis chuii and Dunaliella tertiolecta: Implications for emerging pollutants degradation

In this study, laboratory-scale cultivation of T. chuii and D. tertiolecta was conducted using Conway, F/2, and TMRL media to evaluate their biochemical composition and economic costs. The highest cell density (30.36 × 106 cells/mL) and dry weight (0.65 g/L) for T. chuii were achieved with Conway medium. This medium also produced biomass with maximum lipid content (25.65%), proteins (27.84%), and total carbohydrates (8.45%) compared with F/2 and TMRL media. D. tertiolecta reached a maximum cell density of 17.50 × 106 cells/mL in F/2 medium, which was notably lower than that of T. chuii. Furthermore, the media cost varied from US$0.23 to US$0.74 for each 1 L of media, primarily due to the addition of Na3PO4, KNO3, and cyanocobalamin. Thus, biomass production rates varied between US$38.81 and US$128.80 per kg on a dry weight basis. These findings comprehensively compare laboratory conditions and the costs associated with biomass production in different media. Additionally, this study explored the potential of T. chuii and D. tertiolecta strains, as well as their consortia with bacteria, for the degradation of various emerging pollutants (EPs), including caffeine, salicylic acid, DEET, imidacloprid, MBT, cimetidine, venlafaxine, methylparaben, thiabendazole, and paracetamol. Both microalgal strains demonstrated effective degradation of EPs, with enhanced degradation observed in microalgae-bacterial consortia. These results suggest that the symbiotic relationship between microalgae and bacteria can be harnessed for the bioremediation of EPs, thereby offering valuable insights into the environmental applications of microalgal cultivation.

Acclimatization of a sequencing batch vertical oxidation pond with simulated agricultural wastewater using duckweed as vegetation: analysis of efficiency, Biomass, and Soil properties.

Vertical oxidation pond operated in sequencing batch mode (HRT: 1.25day) with duckweed as the vegetation was used to acclimatize with simulated agricultural wastewater. The maximum removal rate of urea [371g/(m3.d)] and COD [222.4g/(m3.d)] were observed at moderate concentrations of urea (500mg/L), N-P-K (60mg/L), and pesticide (20mg/L). Inhibition and toxicity posed by higher concentrations, decreased the removals of urea (83% to 61%), COD (81% to 51%), and TDS (76% to 50%) at the end of the acclimatization. Steady removal (> 99%) of PO43--P was observed during acclimatization. Effluent pH increased due to the generation of NH4+-N (maximum 370 ± 5mg/L) from the assimilation of urea. Oxidation of ammonia led to the maximum generation of NO2--N and NO3--N of 10mg/L and 9mg/L, respectively. Particles less than 300μm increased, and both specific gravity (from 2.62 to 2.42) and maximum dry density (from 1.73 to 1.30g/cm3) of the base soil decreased with an increase in urea, N-P-K, and pesticide. Reactor biomass increased (1.42 to 1.90g/L) up to initial concentrations of urea (500mg/L), N-P-K (60mg/L), and pesticide (20mg/L), then decreased (1.68g/L) with an increase in concentration.

A Novel Technosol Formulation for Sustainable Landfill Top Covers Using Non-Hazardous Wastes

This study explores the potential of non-hazardous wastes for crafting an engineered soil-like material (Technosol) suitable for landfill capping applications. Three distinct materials—waste foundry sand (WFS), washing aggregate sludge (WAS), and composted biosolids (CBS)—were strategically combined to develop this innovative Technosol. The formulation process involved a comprehensive analysis of their physical–chemical properties, mineral composition, leachate quality, and a series of geotechnical assessments to ensure compliance with landfill top cover construction standards. The blend 90WFS/10WAS showed optimal geotechnical properties for constructing a protective layer, including maximum dry density (1.77 g cm–3), void ratio (0.4), CBR index (23.2), cohesive strength (40 kPa), internal friction (ϕ = 30°), and permeability coefficient (k = 1.48 × 10–6 cm s–1). Further enhancement was achieved by adding 10% CBS, resulting in the development of a functional organo-mineral topsoil horizon (81WFS/9WAS/10CBS). Importantly, leachate analysis confirmed the negligible environmental footprint of this Technosol. Moreover, a pot-based experiment with Brassica juncea planting validated its capacity to support plant growth and establish a vegetative cover on the landfill surface.

Algorithms for Densest Subgraphs of Vertex-Weighted Graphs

Finding the densest subgraph has tremendous potential in computer vision and social network research, among other domains. In computer vision, it can demonstrate essential structures, and in social network research, it aids in identifying closely associated communities. The densest subgraph problem is finding a subgraph with maximum mean density. However, most densest subgraph-finding algorithms are based on edge-weighted graphs, where edge weights can only represent a single value dimension, whereas practical applications involve multiple dimensions. To resolve the challenge, we propose two algorithms for resolving the densest subgraph problem in a vertex-weighted graph. First, we present an exact algorithm that builds upon Goldberg’s original algorithm. Through theoretical exploration and analysis, we rigorously verify our proposed algorithm’s correctness and confirm that it can efficiently run in polynomial time O(n(n + m)log2n) is its temporal complexity. Our approach can be applied to identify closely related subgroups demonstrating the maximum average density in real-life situations. Additionally, we consistently offer an approximation algorithm that guarantees an accurate approximation ratio of 2. In conclusion, our contributions enrich theoretical foundations for addressing the densest subgraph problem.

STUDY ON ENGINEERING PROPERTIES OF SOIL USING STONE DUST AND BAGASSE ASH

In the discipline of civil engineering, soil stabilization is the process of enhancing and improving the engineering qualities of soil so that it can support large loads without failing. The safe and efficient disposal of waste material without causing harm to society is a significant concern in a well-managed ecosystem. Utilizing solid waste products to stabilize soil has become more popular recently as a successful way to manage trash from many sectors. This paper reviews the usage of various solid waste items that have been applied to stabilize soft soils. However, there are numerous approaches and strategies for stabilizing this soil. This research offers a method for stabilizing soft soil using waste products. An investigation into the stabilizing potential of bagasse ash and sisal fiber for highly compressible clayey soil has been prompted by the rising expense of building traditional stabilizers and the necessity of inexpensively consuming industrial and agricultural wastes for value trade. There is a growing demand for sustainable construction, which is why recent research has concentrated on sustainable resource consumption trends. We can employ natural and biodegradable resources, as well as waste products, to obtain. This study was a large-scale laboratory experiment to explore the use of natural fibers, industrial waste, and agricultural waste to improve the engineering qualities of moderately compressible clay. The purpose of this study was to determine whether Stone Dust and Bagasse Ash were suitable for stabilizing clayey soil. The results of testing for consistency limits, maximum dry density, optimal moisture content, UCS, and (soaked) CBR were obtained using percentages of 10%, 15%, and 20% by weight of dry soil for Bagasse Ash and 6%, 8%, and 10% for Stone Dust. In this work, expansive soil was stabilized using Stone Dust and Bagasse Ash. Bagasse Ash was fixed at 15%, after that Stone Dust was changed to 3%, 6%, and 9%. Key Words: Compaction test, CBR, UCS, Stone Dust, Bagasse Ash

In-situ growth of novel iron oxide/iron organic framework composites as efficient electroactive materials of battery supercapacitor hybrids

Iron oxide (Fe2O3) with a high theoretical capacitance, wide potential ranges and easy availability has attracted much attentions as the electrode material of battery supercapacitor hybrids (BSH). Metal–organic framework (MOF) is one of the promising potential energy storage materials due to its large surface area and controllable pore structures. In this work, novel iron oxide/iron organic framework composites (Fe2O3/FeMOF) are in-situ grown on the Ni foam as efficient energy storage electrodes of BSH. By tuning the solvothermal durations, the morphology changes from random sizes of sheets, regular grown vertical sheets, to flower-like structures. The d-spacing also increases for the Fe2O3/FeMOF synthesized using longer solvothermal durations. The optimal Fe2O3/FeMOF electrode synthesized using 9 h shows a high areal capacitance of 10.97 F/cm2 along with an areal capacity of 5.49 F/cm2 at the current density of 35 mA/cm2, owing to the most regular growth of sheets, the large d-spacing, and the smallest charge-transfer resistances. A BSH composed of the Fe2O3/FeMOF positive electrode and a graphene negative electrode shows a maximum energy density of 0.76 mWh/cm2 at 22.5 mW/cm2. The excellent long-term cycling stability with the capacitance retention of 85% and Coulombic efficiency of 98% are also achieved after 10,000 charge/discharge cycles.

Investigation of the pangas (Pangasianodon hypophthalmus) cultivation sustainability in cages at the Ratargul Freshwater Swamp Forest of Bangladesh

AbstractDetermining the most appropriate stocking density for a specific fish species in an ambient condition is essential for successful cage aquaculture in terms of profitability which is mainly governed by growth. The current study was conducted to ascertain which stocking density gives the best result of widely cultured species in cage aquaculture, pangas (Pangasianodon hypophthalmus), at swamp forest environment of Ratargul Freshwater Swamp Forest, Bangladesh in terms of growth, production and economic return. Fish were reared for 93 days at three stocking densities, namely 30, 40 and 50 fish/m3 which were denoted as FSD30, FSD40 and FSD50, respectively, containing three replications of each. Growth and yield comparisons indicated that the stocking density of fish had significant (p < 0.05) effects on growth rate and productivity. Fish cultivated at the maximum density (FSD50) had lower mean weights than fish reared at lower densities. The significantly highest mean weights (376.58 ± 14.65 g) and benefit–cost ratio (BCR) (1.617 ± 0.035) obtained from FSD30 show the suitability of this density in terms of fish growth and profitability of pangas in swamp forest environment.

Effect of cattle manure on soil compaction in the brazilian semi-arid region

Soil organic matter is seen as the most important factor in the assessment of soil management systems that affect soil quality and agricultural sustainability. Cattle manure added to crop residues left on the surface of the soil or incorporated have been used on agricultural properties in the semi-arid region of Brazil in the crop-livestock production system as an alternative for sustainable production. However, information on the benefits that this system can bring regarding the physical and mechanical properties of the soil is still limited. The objective of this study was to evaluate the effect of cattle manure on soil susceptibility to compaction, using the Proctor test. Samples of a “Neossolo Fluvico Ta Eutrofico” were collected at depths of 0 to 5 cm, 5 to 10 cm and 10 to 20 cm of an area cultivated with corn in the semi-arid region of Brazil. The Proctor test was carried out in the laboratory with samples obtained from depths of 0 to 5cm and 5 to 10cm without and with the addition of 15% and 30% of cattle manure. The experimental design was randomized blocks, arranged in a 3x2x3 factorial consisting of soil without manure, soil with 15% manure and soil with 30% manure from both depths and three replications. The maximum soil density, water content and organic carbon were evaluated. The results indicate that cattle manure can be an effective alternative in crop-livestock production systems on agricultural properties in the Brazilian semi-arid region, reducing soil compaction and leveraging agribusiness with sustainability.

Methanol electrooxidation performance of nickel-modified polyaniline thin films for direct methanol fuel cells

A metal–organic composite thin film composed of polyaniline (PANI) and Ni was prepared and characterized for methanol electrooxidation reaction. First, PANI thin films were electrodeposited on a fluorine-doped tin oxide (FTO) coated glass support in an aqueous acidic solution. Subsequently, the polymer film was modified with Ni particles (FTO/PANI-Ni) by chronoamperometric (CA) technique. The composite film was characterized by structural, morphological and electrocatalytic analyses. X-ray diffraction (XRD) results confirmed the crystallization of Ni according to the cubic structure. Scanning electron microscopy (SEM) images showed that the Ni nanoparticles were uniformly dispersed on the PANI surface. The electrocatalytic performance of the FTO/PANI-Ni composite electrode for the methanol electrooxidation reaction was investigated in 0.5 M KOH solution containing methanol using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) techniques. The effects of temperature and methanol concentration on the methanol electrooxidation performance were also studied. The modified composite catalyst exhibited an electrochemically active surface area of 0.5235 cm2. The presence of Ni nanoparticles on the polymer surface promoted the adsorption of methanol molecules and facilitated the oxidation process, leading to higher current densities and better overall performance. The maximum current density was 14 mA cm-2 and the electrode maintain 68 % of its initial activity even after 200 cycles, indicating that the FTO/PANI-Ni electrode exhibited good stability. The high methanol oxidation performance of the composite electrode was associated with large real surface area, a possible synergistic effect between the polymer moleucles and Ni particles as well as high intrinsic activity of Ni for this process.

Gcplyr: an R package for microbial growth curve data analysis

BackgroundCharacterization of microbial growth is of both fundamental and applied interest. Modern platforms can automate collection of high-throughput microbial growth curves, necessitating the development of computational tools to handle and analyze these data to produce insights.ResultsTo address this need, here I present a newly-developed R package: gcplyr. gcplyr can flexibly import growth curve data in common tabular formats, and reshapes it under a tidy framework that is flexible and extendable, enabling users to design custom analyses or plot data with popular visualization packages. gcplyr can also incorporate metadata and generate or import experimental designs to merge with data. Finally, gcplyr carries out model-free (non-parametric) analyses. These analyses do not require mathematical assumptions about microbial growth dynamics, and gcplyr is able to extract a broad range of important traits, including growth rate, doubling time, lag time, maximum density and carrying capacity, diauxie, area under the curve, extinction time, and more.Conclusionsgcplyr makes scripted analyses of growth curve data in R straightforward, streamlines common data wrangling and analysis steps, and easily integrates with common visualization and statistical analyses.

Turbulent and non-turbulent analysis of thermomagnetic convection and heat transfer of darcian radiative nanofluid flow across inclined stretching surface in microgravity environment

Turbulent and non-turbulent analysis of thermomagnetic convection, heating rate and mass transport of Darcian radiating nanofluid flow through porous slanted sheet is the aim of present study. Influence of microgravity is more useful for the movement of thermophoresis nanoparticles with maximum temperature and density. Joule heating, porous medium, magnetic field and thermal radiations are incorporated for the performance of thermal convection. Governing equations are reduced in dimensionless form. Oscillatory stokes conditions are applied to separate the steady, real and imaginary equations. Finite difference, Primitive transformation, and Gaussian elimination techniques are applied for numerical outputs. For asymptotic results, the appropriate range of parameters such as 0.1≤JH≤15.0, 0.1≤Pr≤12.0, 0.1≤Rd≤25.0, 0.0≤λT≤5.0, 0.1≤NT≤1.0, 0.1≤Fr≥6.0, and 0.1≤δ≤1.0 is utilized. Main novelty of work is to examine the steady state and oscillatory behavior of friction-rate, heat/mass transport over slanted two-angles π/6 and π/4. Maximum amplitude in fluid velocity is observed by increasing radiations and buoyant forces. Temperature distribution and nanomaterial concentrations enhance as Joule-heating and Prandtl number increases under microgravity region. Amplitude and oscillation of heat and mass rate is increased as reaction rate, Joule heating and Forchheimer parameter increases. Enhancing behavior of energy transport is observed for maximum choice of Prandtl index with small magnetic effects. It is depicted that high rate of oscillating frequency in heat transmission is detected with maximum radiation effects.

Antimony-Platinum Modulated Contact Enabling Majority Carrier Polarity Selection on a Monolayer Tungsten Diselenide Channel.

We develop a novel metal contact approach using an antimony (Sb)-platinum (Pt) bilayer to mitigate Fermi-level pinning in 2D transition metal dichalcogenide channels. This strategy allows for control over the transport polarity in monolayer WSe2 devices. By adjustment of the Sb interfacial layer thickness from 10 to 30 nm, the effective work function of the contact/WSe2 interface can be tuned from 4.42 eV (p-type) to 4.19 eV (n-type), enabling selectable n-/p-FET operation in enhancement mode. The shift in effective work function is linked to Sb-Se bond formation and an emerging n-doping effect. This work demonstrates high-performance n- and p-FETs with a single WSe2 channel through Sb-Pt contact modulation. After oxide encapsulation, the maximum current density at |VD| = 1 V reaches 170 μA/μm for p-FET and 165 μA/μm for n-FET. This approach shows promise for cost-effective CMOS transistor applications using a single channel material and metal contact scheme.

Antimony-Platinum Modulated Contact Enabling Majority Carrier Polarity Selection on a Monolayer Tungsten Diselenide Channel.

We develop a novel metal contact approach using an antimony (Sb)-platinum (Pt) bilayer to mitigate Fermi-level pinning in 2D transition metal dichalcogenide channels. This strategy allows for control over the transport polarity in monolayer WSe2 devices. By adjustment of the Sb interfacial layer thickness from 10 to 30 nm, the effective work function of the contact/WSe2 interface can be tuned from 4.42 eV (p-type) to 4.19 eV (n-type), enabling selectable n-/p-FET operation in enhancement mode. The shift in effective work function is linked to Sb-Se bond formation and an emerging n-doping effect. This work demonstrates high-performance n- and p-FETs with a single WSe2 channel through Sb-Pt contact modulation. After oxide encapsulation, the maximum current density at |VD| = 1 V reaches 170 μA/μm for p-FET and 165 μA/μm for n-FET. This approach shows promise for cost-effective CMOS transistor applications using a single channel material and metal contact scheme.

Analysis of the Causes and Conditions for the Formation of a High Incidence of Acute Respiratory Infections in the Population of the Altai Krai (Part 2. Environmental factors, diagnosis of coxiellosis and tick­borne rickettsiosis)

Relevance. Altai Krai (AK) is one of the least prosperous subjects of the Russian Federation in terms of the incidence of acute respiratory infections (ARI). Results of studying long-term and intra-annual dynamics of the incidence of ARI and community-acquired pneumonia (CAP) in various population groups of the AK in 2011–2021 led to a conclusion about possible connection between the characteristics of the epidemic process of ARI and environmental factors, primarily air pollution, as well as the widespread distribution of natural and atropurgic foci of tick-borne transmissible and zoonotic infections in the territory of the AK, along with the problems of diagnostics. Aim. Assessment of the possible influence of environmental factors on the formation of a high level of registered incidence of ARI in the Altai Territory, as well as diagnostics of some natural focal and zoonotic infections with fever and respiratory symptoms. Materials and methods. A retrospective epidemiological study was conducted based on annual and monthly official statistical reporting during 2011–2021 about the morbidity of the population, demographic and environmental features of the territory of the AK for each of the municipalities (MU), the average long-term incidence rates of ARI, VBP, tuberculosis, Siberian tick typhus (STT), ixodid tick-borne borreliosis, tick-borne viral encephalitis were calculated; appeals of the population regarding tick bites; population density and annual average sulfur dioxide (SO2) emissions. Pearson correlation coefficient was used to assess the strength of the relationship between the analyzed indicators; and seasonality coefficients and the method of trend-seasonal decomposition were used to assess the intra-annual dynamics of the incidence of ARI and CAP (for the period 2011-2019). To study seroprevalence of antibodies to C. burnetii, R. sibirica and SARS-CoV-2 in febrile patients with symptoms of ARI blood samples were collected in October 2022 from ten rural districts of the AK. Results and discussion. It was established that there was a significant direct correlation between the incidence of ARI and the amount of SO2 emissions into the atmosphere (r = 0.61, p < 0.001), as well as between the incidence of ARI and population density (r = 0.53, p < 0.001). The largest share (69%) of the total number of ARI cases in the Altai Territory in 2011–2021 was attributed to the cities of Barnaul, Biysk, Rubtsovsk, Zarinsk and Novoaltaisk, which are characterized by maximum SO2 emissions and population density. An additional contribution (8% total) to the incidence of ARI in the Altai Territory was attributed to 7 rural areas with the highest levels of SO2 emissions. Regardless of the ranking for the incidence of ARI and CAP, in 9 out of 10 areas selected for the study, patients had both anamnestic and diagnostic titers of antibodies to C. burnetii and/or R. sibirica. At the same time, coxiellosis cases in these areas were not registered for 12 years, and the number of cases of STT was much less than the probable number based on the proportion of patients which were seropositive to R. sibirica and had symptoms of ARI. IgM to SARS-CoV-2 were detected in 5 out of 203 examined samples, IgG – in 188 out of 203 examined samples, moreover 13.8% of samples had 118 to 499 BAU/ml, 40.9% of samples had 500 to 5000 BAU/ml, and the rest of samples had more than 5000 BAU/ml. Conclusion. Among all the variables analyzed in the study, the greatest role in the formation of the high level of registered incidence of ARI in the AK for many years belong to the high level of air pollution with SO2 emissions, high population density and, especially, their combination. Underdiagnosis of tick-borne rickettsioses and coxiellosis is of particular importance due to the unavailability of test kits for laboratory verification. Starting from 2020, a new coronavirus infection made some contribution to the registered incidence of ARI.

Study on the Permanent Deformation and Dynamic Stress–Strain of Coarse-Grained Subgrade Filler under Cyclic Loading

Using coal gangue as a subgrade filler will produce good benefits, and its application prospects are very broad. It is of great engineering and scientific value to study the improvement method and dynamic characteristics of coal gangue subgrade filler under traffic load. Combining the properties of coal gangue material, fly ash and lime and soil were added to improve the bearing behavior of coal gangue subgrade filler. Then, a compaction test was carried out using the principle of orthogonal experimental design. By analyzing the compaction test results, the optimal proportion of each additive was obtained. A large-scale dynamic triaxial test was carried out with the proportion of each admixture in the maximum dry density group in the compaction test. Based on the dynamic triaxial test results, the effect of confining pressure on the permanent strain was analyzed, the analysis model of permanent deformation and cycle number of traffic loading was proposed, and the correctness of the model was verified. In addition, a modified Hardin–Drnevich model was established, which can describe the dynamic stress–dynamic strain curve of coal gangue subgrade filler under traffic load, and then, the dynamic modulus and damping ratio were analyzed.

Three-Dimensional Density And Flight Direction Measurement In The Ballistic Range

Simultaneous measurement of the three-dimensional density field around the Hayabusa-type re-entry capsule model and the angle of attack using the 3D-BOS (Background Oriented Schlieren) technique was carried out in the ballistic range at the Institute of Fluid Science (IFS), Tohoku University. A Hayabusa-type re-entry capsule model with a diameter of 25 mm was used for the test model, and the free-flight Mach number was 1.20. A total of 22 digital cameras were installed for the two set of 3D-BOS measurement system. Each of 11 digital cameras are synchronized and captures the flow field around the test model at two different moments. In this paper, the model position at the different moments were measured using two sets of 3D-BOS measuring systems based on image processing, and the model flight direction and angle of attack were measured. The results showed that the stagnation point predicted from the angle of attack and the maximum density point showed good agreement. Therefore, we conclude that the density distribution around the reentry capsule model obtained by the 3D-BOS technique can be directly compared with the CFD results.

Three-Dimensional Density And Flight Direction Measurement In The Ballistic Range

Simultaneous measurement of the three-dimensional density field around the Hayabusa-type re-entry capsule model and the angle of attack using the 3D-BOS (Background Oriented Schlieren) technique was carried out in the ballistic range at the Institute of Fluid Science (IFS), Tohoku University. A Hayabusa-type re-entry capsule model with a diameter of 25 mm was used for the test model, and the free-flight Mach number was 1.20. A total of 22 digital cameras were installed for the two set of 3D-BOS measurement system. Each of 11 digital cameras are synchronized and captures the flow field around the test model at two different moments. In this paper, the model position at the different moments were measured using two sets of 3D-BOS measuring systems based on image processing, and the model flight direction and angle of attack were measured. The results showed that the stagnation point predicted from the angle of attack and the maximum density point showed good agreement. Therefore, we conclude that the density distribution around the reentry capsule model obtained by the 3D-BOS technique can be directly compared with the CFD results.

The enhancement and impact of Se doping on the electrochemical properties of LiMn2O4 cathode material for aqueous Li-ion batteries

Spinel LiMn2O4 is a promising cathode material for lithium-ion batteries. However, due to the Jahn-Teller effect and Mn dissolution, its capacity decreases seriously in the cycle process, which hinders its wider application. In the course of our research, we discovered that a modest infusion of Se-doping is capable of significantly augmenting the oxygen vacancy within the material, improve the conductivity of the LiMn2O4 material and promotes superior battery performance. Moreover, due to Se-doped the average valence state of Mn is raised, which effectively mitigates the Jahn-Teller effect. The optimized sample exhibits high capacity, long cycle life, and superior rate capability, with an initial discharge specific capacity of 101.0 mAh·g−1 at 7 C and capacity retention of 87.3 % after 200 cycles. The maximum specific discharge capacity of the full battery during the cycle was 97.9 mAh·g−1, the capacity retention rate after 200 cycles was 78.2 %, and the maximum energy density during the cycle is 145.1 Wh·Kg−1, which was nearly twice that of the single lithium-ion battery in this paper. The effect of Se-doped on the properties of LiMn2O4 cathode materials provides a new idea for the development of high-performance spinel lithium manganese oxide cathode materials.

An integration of µXRF and X-ray microdensitometry records in dendrochronology

X-ray based microdensitometry is conventionally used to produce climate-related tree-ring records. Micro X-ray fluorescence (µXRF) applications represent another growing area of interest and opportunities in dendrochronology. This paper demonstrates a method to correctly juxtapose and precisely synchronise the densitometry and µXRF profiles. Among µXRF variables, full fluorescence spectrum (FFS) corresponds distinctly well with the microdensitometry-based wood density variations. Accordingly, the FFS provides the most applicable variable to integrate the µXRF and density profiles. The method proposed here can be used to demonstrate the strength and sign of µXRF variables and wood density relations. Moreover, the µXRF based records can be readily compared to density variables, such as the latewood maximum density, which is demonstrated in this paper.

Initial pyrolysis of perhydroacenaphthene conformers: A multi-scale simulation and experimental analysis

The enduring quest for a fuel that embodies both high density and superior heat sink capacity has been a long-standing goal within the scientific community. Perhydroacenaphthene (PHAN) fuels, characterized by five-membered ring structure that enhances density, also serve as hydrogen donors to inhibit coking, showcasing significant potential in fuel applications. Given their "strain-free" cyclic configuration, PHAN fuels manifest diverse conformations like chair, boat, and twist, among others, each influencing fuel properties and subsequently affecting pyrolysis process and the utilization of heat sink. In this work, leveraging the five preferred PHAN conformers substantiated by experiments, we embarked on a comprehensive investigation into their microstructures, properties, pyrolysis behavior, and initial pyrolysis mechanisms combining with molecular simulation and experimental analysis. Among them, interaction region indicator (IRI) analysis was employed to elucidate the differences in density. Upon this foundation, taking trans-trans-trans and cis-cis-cis PHAN with minimum and maximum density as models, the effects of different conformations on the initial pyrolysis reaction were explored by micro-pyrolysis system attached to an online GC-MS/FID strategy. It was found that compared to the trans-trans-trans conformation, the cis-cis-cis conformation manifested superior initial pyrolysis activity and more substantial heat sink capacity. Moreover, upon delving into the reaction mechanism and microkinetic analysis, it became evident that the favored initial reaction type of PHAN pyrolysis was H-abstraction reaction, and cis-cis-cis PHAN presented a lower barrier and a faster reaction rate than trans-trans-trans. Additionally, in conjunction with the calculation of free energy barrier and reaction heat of numerous reactions, the kinetic and thermodynamic dominances for the initial pyrolysis pathways of trans-trans-trans and cis-cis-cis PHAN were identified. Finally, utilizing intermolecular interaction energy (ΔE), independent gradient model based on Hirshfeld partition (IGMH) and Xiamen energy decomposition analysis (XEDA), the microscale justification for cis-cis-cis PHAN conformation displaying superior initial pyrolysis activity was further unveiled. This endeavors pioneer innovative pathways for the directional development and application of PHAN conformers.