Higher Density Values Research Articles

Interactions involved in the adsorption of ethylene glycol and 2-hydroxyethoxide on the Au(111) surface: a Density Functional Theory study

AbstractContext: The monolayers of ethylene glycol and 2-hydroxyethoxide on gold surfaces have been used in hybrid materials as biosensors. In this article, the adsorption of ethylene glycol and 2-hydroxyethoxide on the Au(111) surface was analyzed. For the first system, ethylene glycol on Au(111), there are Au$$\cdot \cdot \cdot $$ · · · O and Au$$\cdot \cdot \cdot $$ · · · H interactions. To the best of our knowledge, the Au$$\cdot \cdot \cdot $$ · · · H interaction has been overlooked until now. However, in this work, there is strong evidence that this interaction is important to stabilize the system. For the second system, the atomic interactions mentioned previously are also predicted, although there is an additional interaction between 2-hydroxyethoxide molecules. Such an interaction induces the link -O-H-O-, with high values of the electron density at the critical points of the corresponding bond path of the O-H interaction. These links suggest the forming of ethylene glycol chains. Methods: The calculations were performed using two exchange-correlation functionals: BEEF-vdW and C09$$_{x}$$ x -vdW; both functionals incorporate dispersion effects within the Kohn-Sham approach in Density Functional Theory as implemented in GPAW code and ASE computational packages. The contacts between the molecules considered in this article and the Au(111) surface were analyzed through the Quantum Theory of Atoms in Molecules implemented in GPUAM code.

Thickness and Doping Density Influence of a High-Voltage Inorganic Perovskite Solar Cell: A SCAPS 1-D Simulation Study

Recently, all inorganic perovskite solar cells have triggered great attention thanks to the rising performance during their development in solid state photovoltaics showing enhanced characteristics, such as: good stability, high photoluminescence quantum yield, tunable size, and morphology. In this work, a high open-circuit voltage solar cell based on all-inorganic perovskite through SCAPS simulator program is presented by analysing electron transport layer (ETL), perovskite layer, hole transport layer (HTL) thickness and doping density from a FTO/TiO2/CsPbBr3/Spiro-OMeTAD/Au structure were modified to observe its influence on solar cell performance. Therefore, simulation results show that a thicker ETL hinders carrier transport towards the FTO layer due to larger distance which leads to higher recombination rate, reducing carrier’s lifetime. Albeit high doping density values in ETL enhances the overall solar cell performance. As for the absorber layer, while its thickness increases, carrier collection rate decreases due to recombination impacting Voc, which results from thickness increase. Based on the results, solar cell efficiency improvement is attributed to the built-in electric field as absorber layer doping density increases. While HTL thickness has minimum impact on the solar cell output, doping density enhances device parameters significantly. Summarising the results obtained from thickness and doping density simulations, the optimal solar cell operation was obtained at 10 nm, 600 nm, and 100 nm layer thickness as well as 1020 cm-3, 1016 cm-3, and 1020 cm-3 doping density (TiO2, CsPbBr3 and Spiro-OMeTAD). Results from three different sources, collected from literature, were used to compare, and fitting them along with simulation results.

Structural Performance of GFRP-Wrapped Concrete Elements: Sustainable Solution for Coastal Protection

Protecting coastal regions is crucial due to high population density and significant economic value. While numerous strategies have been proposed to mitigate scouring and protect coastal structures, existing techniques have limitations. This paper introduces a novel approach, SEAHIVE®, which enhances the performance of engineered structures by utilizing hexagonal, hollow, and perforated concrete elements externally reinforced with glass fiber-reinforced polymer (GFRP). Unlike conventional steel bars, GFRP offers superior durability and requires less maintenance, making it a sustainable solution for any riverine and coastal environment. SEAHIVE® aims to provide robust structural capacity, effective energy dissipation, and preservation of natural habitats. Although some research has addressed energy dissipation and performance in riverine and coastal contexts, the structural performance of SEAHIVE® elements has not been extensively studied. This paper evaluates SEAHIVE® elements reinforced with externally bonded GFRP longitudinal strips and pretensioned GFRP transverse wraps. Testing full-size specimens under compression and flexure revealed that failure occurred when the pretensioned GFRP wraps failed in compression tests and when longitudinal GFRP strips slipped in flexure tests. Strength capacity was notably improved by anchoring the GFRP strips at both ends. These findings underscore the potential of the SEAHIVE® system to significantly enhance the durability and performance of coastal and riverine protection structures. FEM simulations provided critical insights into the failure mechanism and validated the experimental findings. In fact, by comparing FEM model results for cases before and after applying GFRP wraps under the same compression load, it was found that maximum stresses at crack locations were significantly reduced due to compression forces resulting from the presence of pretensioned GFRP wraps. Similarly, FEM model analysis on flexure samples showed that the most vulnerable regions corresponded to the locations where cracks started during testing.

X-Shooting ULLYSES: Massive Stars at low metallicity. IX.Empirical constraints on mass-loss rates and clumping parameters for OB supergiants in the Large Magellanic Cloud

Current implementations of mass loss for hot, massive stars in stellar evolution models usually include a sharp increase in mass loss when blue supergiants become cooler than $T_ eff 20-22$ kK. Such a drastic mass-loss jump has traditionally been motivated by the potential presence of a so-called bistability ionisation effect, which may occur for line-driven winds in this temperature region due to recombination of important line-driving ions. We perform quantitative spectroscopy using UV (ULLYSES program) and optical (XShootU collaboration) data for 17 OB-supergiant stars in the LMC (covering the range $T_ eff 14-32$ kK), deriving absolute constraints on global stellar, wind, and clumping parameters. We examine whether there are any empirical signs of a mass-loss jump in the investigated region, and we study the clumped nature of the wind. We used a combination of the model atmosphere code fastwind and the genetic algorithm (GA) code Kiwi-GA to fit synthetic spectra of a multitude of diagnostic spectral lines in the optical and UV. We find an almost monotonic decrease of mass-loss rate with effective temperature, with no signs of any upward mass loss jump anywhere in the examined region. Standard theoretical comparison models, which include a strong bistability jump thus severely overpredict the empirical mass-loss rates on the cool side of the predicted jump. Another key result is that across our sample we find that on average about 40<!PCT!> of the total wind mass seems to reside in the more diluted medium in between dense clumps. Our derived mass-loss rates suggest that for applications such as stellar evolution one should not include a drastic bistability jump in mass loss for stars in the temperature and luminosity region investigated here. The derived high values of interclump density further suggest that the common assumption of an effectively void interclump medium (applied in the vast majority of spectroscopic studies of hot star winds) is not generally valid in this parameter regime.

Built environmental characteristics, physical activity in neighbourhoods of Accra, Ghana

Abstract There is increasing evidence that characteristics of the built environment can influence residents’ lifestyles, physical activity thereby influencing the development of obesity and non-communicable diseases even in low- and middle-income countries. The aim of this study is to describe the characteristics of the built and the social environment of neighbourhoods of Accra, Ghana, and to explore association between neighbourhood characteristics and the physical activity of the residents. A cross-sectional study was conducted in Accra, 12 neighbourhoods were randomly selected based on high and low values of residential density and socioeconomic status. Sociodemographic, household and neighbourhood information were collected with an adapted questionnaire of NEWS (Neighbourhood Environment Walkability Scale) for Africa. Physical activity was assessed by WHO Global Physical Activity Questionnaire and social cohesion by the Perceived Neighbourhood Social Cohesion Questionnaire. Differences between variables by neighbourhood types were analysed using Chi square test and Kruskal Wallis test. Generalized linear model was performed to determine the association between neighbourhood characteristics and residents’ physical activity. The built environmental characteristics of different neighbourhood types and the physical activity of the residents showed significant differences. The associations indicated that individuals living in high residential density neighbourhoods had increased levels of engaging in physical activities. Land use mix, street connectivity, safety, aesthetics and social cohesion of neighbourhoods showed correlation with physical activity of residents. The built environment and social characteristics of neighbourhoods can influence the lifestyle and physical activity of residents in Accra, Ghana. Key messages • High residential density neighbourhoods correlated with higher level of physical activity. • Land use, street connectivity, safety and aesthetic of neighbourhoods and social cohesion showed correlation with physical activity.

Achieving Higher Critical Current Density in LGPS-Based Lithium Metal Batteries via a Synergistic Interlayer for Physical Inhibition and Chemical Scavenging of Lithium Dendrites.

Li10.35Ge1.35P1.65S12 (LGPS) electrolyte has garnered attention due to its high ionic conductivity and processability. However, its strong incompatibility with lithium metal hinders its practical application. Conventional interlayer strategy isolates Li from LGPS, avoiding the detrimental side reactions, but lithium dendrite penetration is still a problem. To address the aforementioned challenges, we develop a PVDF-HFP-supported PDOL-based interlayer (PDOL/PVDF-HFP), which stabilizes the LGPS/Li interface by synergistically physically inhibiting and chemically scavenging lithium dendrites. The multifunctional feature of the interlayer comes from the use of a bifunctional initiator, InCl3. On the one hand, InCl3 induces the polymerization of DOL, forming a physical separator and protecting lithium from LGPS; on the other hand, in situ reactions between In3+/Cl- and Li form a LiCl/LiF/LiIn hybrid SEI, homogenizing the surface Li+ flux and suppressing lithium dendrite formation and penetration. In addition, an unexpected dynamic microdendrite scavenging is realized by virtue of the side reactions of LGPS/Li, which converts the undesirable reaction to be an advantage in our design. Benefiting from the comprehensive advantages of such design, the constructed sulfide-based solid-state batteries achieve a super low interfacial impedance of 5.1 Ω, a high critical current density (CCD) value over 5 mA/cm2, and a super long cycling stability over 8000 h. Our synergistic interlayer strategy would open an effective avenue for solving interfacial challenges for practical sulfide-based solid-state batteries.

Cultivated Land Information Extraction and Spatial Pattern Analysis in Beijing Based on Deep Learning

Abstract. Cultivated land is the basic resource and material condition for human survival, providing the necessary material basis for agricultural development and agricultural modernization (Tian and Shi, 2024). For this reason, this paper takes Beijing as an experimental area to study the cultivated land extraction method and analyze the distribution pattern of cultivated land and the degree of fragmentation. The results show that (1) the extraction results are evaluated by using confusion matrix and Kappa coefficient, and the Kappa coefficient is obtained to be 0.8358.(2) The cultivated land in Beijing is mainly distributed in the southeast as well as the northwest of the local area of gentle terrain, and the The range of the extremely high value of cultivated land kernel density in 2017–2022 is significantly reduced, the slope of the area with the smallest reduction in the proportion of cultivated land is less than 5°, the reduction in the area of cultivated land in water resource-rich areas is small, and the reduction in the proportion of cultivated land in road-intensive areas is large. (3) Due to various natural factors and human activities, the degree of cultivated land fragmentation in Beijing is increasing, the boundary shape of cultivated land patches tends to be irregular.

Effects of Boron Supplementation in Dairy Cow Close-Up Rations on Colostrum Quality and Certain Blood Metabolites in Calves.

In this study, we aimed to investigate the effects of different levels of boron supplementation to the diet during the close-up period and the first postpartum day on postpartum colostrum quality, immunoglobulin levels in colostrum, and certain calf blood parameters in dairy cattle (n = 21). Two experimental groups and one control (C) group were formed. Boron at 300ppm (T-300) and 600ppm (T-600) was added to the experimental rations. The daily dry matter intake (DMI), body condition score (BCS) of dairy cattle, and body weight (BW) of calves were recorded. Colostrum samples were collected during the first 2 postpartum milkings, and their components were determined. Blood samples were collected from calves at 24 and 48hours after colostrum feeding. The addition of boron to rations during the close-up dry period increased the DMI of cows and the BW of calves born to the T-600 group (p < 0.05). The addition of boron to the rations changed the total protein (TP) and nonesterified fatty acid (NEFA) values in the calf blood samples taken 48hours after birth from those of the control group (p < 0.05). The differences between the blood boron values of the experimental and control groups at 24 and 48hours after colostrum and colostrum feeding were significant (p < 0.05). At the first milking after birth, the colostrum DM value and density were highest in the T-600 group (p < 0.05). In conclusion, due to the high density value of colostrum according to the quality classification of colostrum in the first postpartum milking and the increase in calf blood IgG levels at 48 hours compared to the control group, it may be considered to add up to 600 ppm boron to the rations of cows close-up period in order to improve calf health and prevent calf losses due to colostrum quality.

A Versatile InF3 Substituted Argyrodite Sulfide Electrolyte Toward Ultrathin Films for All‐Solid‐State Lithium Batteries

AbstractAll‐solid‐state lithium batteries (ASSLBs) incorporating sulfide solid electrolytes capture great attention due to their intrinsic safety features and high energy density. Nevertheless, the implementation of sulfide solid electrolytes faces significant challenges, including moisture sensitivity, narrow intrinsic electrochemical windows, and excessively thick solid electrolyte layers. Here, the substitution of In for P and F for Cl in argyrodite sulfide Li5.7PS4.7Cl1.3 is presented. With appropriate elemental substitutions, the Li symmetric cells exhibit a high critical current density value of 2.5 mA cm−2 and deliver prolonged plating/stripping over 1000 h at 1 mA cm−2 and 25 °C. Further, the Li5.82P0.94In0.06S4.7Cl1.12F0.18 displays high chemical stability toward organic solvents, which is further demonstrated by the density functional theory (DFT) calculations. Using polyisobutylene as a binder, a uniform sulfide film (35 µm) is prepared by slurry casting and hot pressing process, delivering a high ionic conductivity of 1.4 mS cm−1 at 25 °C. Coupled with FeS2 and LiCoO2 cathode, the all‐solid‐state lithium metal cell exhibits a long cycling life and excellent rate performance. This study provides a design strategy and reveals the importance of high‐performance sulfide SEs in the scalable production of sulfide film.

Variable density and heat generation impact on chemically reactive carreau nanofluid heat-mass transfer over stretching sheet with convective heat condition

The present study focuses on the physical significance of heat generation and chemical reaction on Carreau nanofluid with convective heat conditions. Heat transfer is characterized using convective boundary conditions. The governing partial differential equations (PDEs) are transformed into ordinary differential equations (ODEs) by using well define stream functions and similarity transformations. Using a shooting methodology, the Keller-box method with Newton Raphson scheme is used to elaborate the numerical solutions of physical phenomena. Utilizing a similar technique to find the impact of physical parameter such as the production of heat δ, the rate of reaction Λ, Biot numbers γ, Brownian motion variable Nb, the thermophoresis parameters Nt, the Weissenberg quantity We, Prandtl number Pr, and Lewis number Le on velocity profile, temperature profile and mass transmission profile are determined graphically. The skin-friction coefficient −f″(0), local Nusselt −θ′(0), and Sherwood numbers −ϕ′(0) are analyzed numerically. Increment in fluid velocity and slip temperature are depicted with high Biot number. Maximum magnitude of fluid temperature and fluid concentration function are depicted at high value of temperature dependent density. The magnitude of heat and mass transportation enhanced with maximum choice of Brownian motion.

Boosting photoelectrochemical water splitting performance via nanostructured Ag-CuO thin films

Undoped and doped copper oxide (CuO) with silver (Ag) was prepared using the SILAR technique on the ITO substrate to generate green hydrogen from the water-splitting process. The (−111) and (111) were the most intense reflections of crystallographic planes observed in pure and Ag-doped CuO thin films. Ag doping within the crystal structure of pristine leads to increasing the crystallite size. FESEM images show homogeneity and uniform distribution for the pure and Ag-doped CuO thin films that confirm the particles have small sizes, give more features and are responsible for the target application. The doping process affected the energy band gap where it was 2.2 eV for the pure sample then descended to 1.9 eV as doping reached 5 % concentration of Ag element. The photoelectrochemical testing showed that the Ag 5 % content photoelectrode has a high value of photocurrent density approximately ∼ - 5 mA/cm2.

Electron Densities in H ii Regions from Observation of [N ii] 205 μm Fine Structure and Radio Recombination Lines

We employ observations of the 205 μm [N ii] fine structure (FS) line and radio recombination line (RRL) emission to derive the electron density in 10 well-known H ii regions. The combination of these two spectral lines (the RRL–FS line method) provides a sensitive probe of electron density in regions with n(e) ≥ 30 cm−3 without requiring knowledge of the size of the ionized region. By using H54α data from the Green Bank Telescope and 205 μm data from the SOFIA Airborne Observatory, we have almost identical 18″ beamwidths, removing a significant source of error for observations of H ii regions due to nonuniform density across the sources observed. The electron densities vary widely among the sources observed, from 2600 to 36,000 cm−3, with two low-density outliers at 94 and 520 cm−3. On average, these densities are a factor of 4 greater than the highest-resolution single-antenna data and a factor of almost 13 greater than the 182″ angular resolution single-antenna data having more sources in common. The total 1σ fractional uncertainties in n(e) are in the range 0.15–0.29. In the RRL–FS line method, the observationally determined quantity is proportional to ∫n 2(z)dz / ∫n(z)dz. For a Gaussian density distribution much more extended than its 1/e radius, this is equal to n0/2 , where n 0 is the peak electron density. The high values of electron density found are plausibly the result of the RRL–FS line technique sampling the peak of a centrally condensed density distribution.

Effects of the phase transition on the photoelectrochemical properties of CuFe2O4 composite photoelectrode

In this study, CuFe2O4 was grown using various Cu:Fe source molar ratios. The morphological, structural, electrical, and photoelectrochemical properties of CuFe2O4 photoelectrodes with different structural phases based on molar ratios were analyzed. XRD and XPS were performed to systematically analyze the relationship between the structural and photoelectrochemical properties of the photoelectrode. XRD analysis revealed the phase transformation of CuFe2O4 from cubic to tetragonal phase and back to cubic phase as the Cu:Fe source molar ratio was varied. The crystallinity of Cu-rich cubic-CuFe2O4 was found to be superior to that of tetragonal-CuFe2O4. XPS analysis showed that the Cu-rich cubic-CuFe2O4 sample has higher Cu and Fe binding energies and more oxygen vacancies than the tetragonal-CuFe2O4 sample, which helps reduce carrier recombination. Additionally, cubic-CuFe2O4 samples prepared in Cu-rich conditions demonstrated high flat-band potential and low charge transfer resistance values. As a result, the cubic-CuFe2O4 photoelectrode sample under the Cu-rich condition exhibited a relatively high photocurrent density value. The highest photocurrent density value (-0.38mA/cm2 at -0.55 VSCE) was obtained with cubic-CuFe2O4 samples prepared under the Cu:Fe 3:1 condition.

Improving the steering performance of microrobots by using a magnetically actuated technique

Mobile microrobots show the significance of potential medical procedures and challenge areas within the human body. An applied electromagnetic field is used as a precise magnetic actuation system for controllable steering mobility, and positioning is used. In this work, an adaptable microrobot is developed with an effective technique to enhance steering. An electromagnetic system is employed to produce an external magnetic field that guides a microrobot to improve its steerability. In particular, a driving system of eight coils creates a magnetic field that actuates the microrobot and enables upward and downward motion. Accordingly, three types of microrobot designs are proposed. Consequently, an efficient variation of steering in terms of deformation angle is achieved. The corresponding performance is determined mathematically in terms of the main system parameters, such as external magnetic field and microrobot geometry. In addition, finite element model is used for comparison and validation. Simulation results show that for a relatively high value of magnet field, namely, 15 mT and 90°, the deformation angles were 36.98° for the first design, 39.11° for the second design, and 34.48° for the third design in upward deformation. By contrast, the downward deformation ranges were –40.42°, –39.46°, and –37.04° for the first, second, and third designs, respectively, at –90° The error between the upward and downward steering of the second design had the lowest value of 0.35° The second design of the microrobots has the least error between the upward and downward deformation ratio at 0.89 %. In comparison, the first design has a 9.3 % error, and the third design has a 7.42 % error, with a relatively high value of magnetic field density (15 mT). Simulations have shown that the proposed second design is suitable for navigating narrow artery branches with the least error ratio and more precise control. This work verifies that the model could accurately control the steering of microrobots.

Combined physiological, metabolomic and response surface approaches to analyze copper stress resistance mechanisms and repair potential of Epipremnum aureum

Phytoremediation is commonly used to remediate copper (Cu) pollution in water bodies. Epipremnum aureum is often used as a restoration plant because of its rapid reproduction, high population density and high landscape value. However, neither its ability to remediate Cu-polluted water nor its mechanism of resistance to Cu stress has been fully clarified. Therefore, the present study revealed the Cu removal ability and resistance mechanism of E. aureum through physiology and metabolomics. And based on the results of this study, the response surface was applied to the application of plant growth regulator (PGR) to propose a precise restoration program. We first examined the growth physiological indices and repair of Cu in E. aureum under different Cu stress levels and found that the resistance mechanism of E. aureum to Cu was significantly initiated at 400 mg·L-1. And as the level of Cu stress increased, the Cu content in the plant also increased, and the underground part was the main accumulating part. The translocation factor of E. aureum was <1, and the bioconcentration factor was greater than 1 at all different Cu concentrations. Subsequently, metabolomics studies on E. aureum concluded that arginine and proline metabolism, indole alkaloid synthesis and brassinosteroid biosynthesis are the major pathways involved in the mechanism of Cu stress resistance in E. aureum. Based on these results, we proposed that salicylic acid, sodium nitroprusside and 2,4-epibrassinolide could be selected as PGRs, and further optimized the administration of PGRs using response surfaces. The optimized scheme allowed E. aureum to reach a maximum Cu removal of 84.39 % under 400 mg·L-1 Cu stress, which was 35.61 % higher than the non-fortified treatment. This study provides supporting materials and application options for the Cu repair capacity and resistance mechanisms of E. aureum.

Pristine NASICON Electrolyte: A High Ionic Conductivity and Enhanced Dendrite Resistance Through Zirconia (ZrO2) Impurity-free Solid-Electrolyte Design.

Sodium batteries are considered a promising candidate for large-scale grid storage at tropical climate zone, and solid-state sodium metal batteries have a strong proposition as high energy density battery. The main challenge is to develop ultra-pure solid-state ceramic electrolyte and compatible metal interface. Here, a scalable and energy-efficient synthesis strategy of sodium (Na) Super Ionic CONductor, Na1+xZr2SixP3-xO12(x = 2, NZSP) solid electrolyte, has been introduced with the complete removal of unreacted zirconium oxide (ZrO2) impurities. Additionally, the reaction mechanism for the formation of pure phase NZSP is reported for the first time. The NZSP prepared by utilizing the Zr precursor, i.e., tetragonal zirconium oxide (t-ZrO2) derived from the Zr(OH)4 gets quickly and completely consumed in the synthesis process leaving no unreacted monoclinic ZrO2 impurities. The synthesis process only needs a minimum stay of 4 h, which is three times less than the conventional synthesis method. The elimination of ZrO2 impurities results in a 2.5-fold reduction in grain boundary resistivity, showcasing a total ionic conductivity of 1.75 mS cm-1 at room temperature and a relative density of 98%. The prepared electrolyte demonstrates remarkable resistance to dendrite formation, as evidenced by a high critical current density value of 1.4mA cm-2.

Investigation of nuclear structure and [formula omitted]-decay properties of As isotopes

The nuclear ground state properties of 67−80As nuclei have been investigated within the framework of relativistic mean field (RMF) approach. The RMF model with density-dependent (DD-ME2) interaction is utilized for the calculation of potential energy curves and the nuclear ground-state deformation parameters (β2) of selected As isotopes. Later, the β-decay properties of As isotopes were studied using the proton–neutron quasi particle random phase approximation (pn-QRPA) model. These include Gamow Tellar (GT) strength distributions, log ft values, β-decay half-lives, stellar β± decays and stellar electron/positron capture rates. The β2 values computed from RMF model were employed in the pn-QRPA model as an input parameter for the calculations of β-decay properties for 67−80As. The calculated log ft values were in decent agreement with the measured data. The predicted β-decay half-lives matched the experimental values within a factor of 10. The stellar rates were compared with the shell model results. Only at high temperature and density values, the sum of β+ and electron capture rates had a finite contribution. On the other hand, the sum of β− and positron capture rates were sizeable only at low density and high temperature values. For all such cases, the pn-QRPA rates were found to be bigger than the shell model rates up to a factor of 33 or more. The findings reported in the current investigation could prove valuable for simulating the late-stage stellar evolution of massive stars.

A quantitative comparison of economic viability, volatile organic compounds, and particle-bound carbon emissions from a diesel engine fueled with biodiesel blends

Despite the environmental advantages of biofuel blends, detailed studies on emissions of polycyclic aromatic hydrocarbons (PAHs), n-alkanes, and particle-bound carbon from diesel engines, particularly when fueled with biodiesel, remain limited. This study addresses these gaps by analyzing biodiesel blends from neem, linseed, and jatropha oils produced via mechanical extraction and assessing their impact on volatile organic compounds and particle-bound carbon emissions in diesel engine. Economic evaluations of production costs, engine modifications, and payback periods are also conducted. The result shows that jatropha biodiesel exhibits a calorific value of 35.7 MJ/kg, while neem biodiesel shows superior oxidative stability due to its low iodine value. Additionally, linseed biodiesel displays favorable cold flow properties due to its high density and cetane value. Compared to D100, the N10 and N30 blend notably reduced high molecular weight PAH emissions by 10.7 % and 38.4 %, respectively, with the N30 blend achieving a remarkable 76 % reduction in formaldehyde emissions. Conversely, the J10 blend increased specific PAHs, while the J30 blend reduced PAHs by 21.3 %. Both L10 and L30 blends showed reduced naphthalene emissions, with the J30 blend notably reducing elemental carbon (EC) by 31.4 %, although organic carbon (OC) slightly increased. In contrast, the N30 blend decreased both EC and OC emissions, demonstrating a dose-dependent relationship between biodiesel concentration and emissions reduction. Overall, Jatropha biodiesel blends offer the best balance of economic efficiency and emission reductions, resulting in shorter payback periods and lower carcinogenic risks. Neem and linseed blends also provide environmental benefits but with varying economic implications, highlighting the trade-offs between production costs and long-term sustainability.

Spark plasma sintering of cenosphere-derived Cs/Sr-aluminosilicates for 137Cs and 90Sr immobilization in mineral-like ceramics

In this study, a promising method of spark plasma sintering (SPS) was investigated for the fabrication of ceramic matrices designed for the reliable immobilization of highly radioactive radionuclides 137Cs and 90Sr. The ceramic matrices were derived from a mixed composition of two aluminosilicate mineral-like phases – pollucite (Cs,Na)AlSi2O6 and gehlenite Sr2Al2SiO7. The originality of the developed approach lies in the utilization of hydrothermal synthesis for obtaining granulated precursor material. Hollow aluminosilicate microspheres (cenospheres) from coal fly ash served as the initial raw material, which were treated with alkaline solutions containing Cs+ and Sr2+ ions as simulants for the corresponding radionuclides. This method facilitated the achievement of high efficiency in cation removal from solutions exceeding 98 %. For a comprehensive examination of the composition and morphology of cenosphere-derived precursor particles, and the influence of sintering temperature on phase and structure formation of ceramic matrices under non-equilibrium conditions of spark plasma heating, various analytical techniques were employed. These included thermogravimetry/differential thermal analysis (TG/DTA), powdered X-ray diffraction analysis (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), as well as the method of low-temperature nitrogen adsorption for determining the specific surface area. The obtained ceramic samples exhibited high values of specific density (2.688–2.915 g/cm³), compressive strength (666–808 MPa), and Vickers microhardness (1.8–2.5 GPa), attesting to their high quality and stability. The results of the hydrolytic stability assessment revealed that the leaching rates of Cs+ and Sr2+ ions from the ceramics are extremely low, within the range of 10−5–10−6 g/cm²·day. These values fully satisfy the requirements of GOST R 50926–96 and the international standard ISO 6961:1982 for solidified forms of high-level waste.

Moraceae diversity in the Universitas Sumatera Utara’s arboretum

The arboretum of the Universitas Sumatera Utara (USU) is an area for collecting and conserving tree species in North Sumatra. One of dominant family found in USU Arboretum is Moraceae. The objective of this reserach was to determine Moraceae diversity in the USU Arboretum. The census approach of vegetation analysis was used to determine the identity and abundance of Moracea. The research found 9 (nine) Moraceae species belongs to two genera in the USU arboretum, those were Ficus microcarpa, Ficus elastic, Artocarpus heterophyllus, Ficus padana, Ficus fistulosa, Artocarpus altilis, Ficus benjamina, Ficus ampelas and Ficus hispida. The species with the highest density value (57.92%) is Ficus hispida. The diversity index, richness index, and species dominance index were all quite low in the research location, with values of 1.455, 1.226, and 0.370, respectively. Meanwhile, the species evenness index at the research location is 0.662, which is classified into moderate. To improve the diversity of Moraceae in the USU arboretum, species enrichment activities are needed.