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This paper presents the results of a selective flocculation/magnetic separation study performed with a sample of iron ore slime from the desliming stage of the industrial flotation circuit of a mine in the southern region in the Quadrilátero Ferrífero-Brazil that was discarded in a tailings dam. Zeta potential measurements of pure minerals previously identified in the sample (goethite = 52.4%, hematite = 26.2%, quartz = 12.3%, kaolinite = 8.2%, and others = 0. 9%) were evaluated to assess the influence of the reagents used (sodium hexametaphosphate – SHMP (dispersant)) and flocculants (corn starch, nonionic polyacrylamide – P2500 and cationic polyacrylamide – P806)) on their surface properties and consequently on the stability of suspensions of the slime and of the pure minerals individually, aiming to establish conditions for selective separation between Fe-bearing minerals (goethite and hematite) and gangue minerals (quartz and kaolinite) in the subsequent magnetic separation step. At pH 10 and a 25 mg/L dosage of SHMP, a higher Fe recovery was verified with starch (2000 g/t) in relation to nonionic and cationic polyacrylamides, and similar Fe contents in all dosages tested of the flocculants. [ABSTRACT FROM AUTHOR]

Blue, green, and khaki spinels were produced by self-propagating high-temperature synthesis (SHS) using Co 3 O 4 –ZnO–Mg(NO 3) 2 ·6H 2 O–Al(OH) 3 –Al, Ni 2 O 3 –ZnO–Cr 2 O 3 –Al(OH) 3 –Al, and Co 2 O 3 –Fe 2 O 3 –Al(OH) 3 –Al mixtures. The composition of the synthesis products was characterized by X-ray diffraction and IR spectroscopy. The oxides Co 3 O 4 , Co 2 O 3 , ZnO, Ni 2 O 3 , Cr 2 O 3 , Fe 2 O 3 , and aluminum hydroxide Al(OH) 3 were used for the synthesis. Fuel was provided by aluminum powder (ASD-4). The spinel-type ceramic pigments were synthesized using layer-by-layer combustion, which involves two parallel exothermic reactions: aluminum oxidation and aluminothermic reactions. The fast self-propagating reactions and high synthesis temperatures rapidly destroy the structure of Al(OH) 3 hydroxide in the starting mixture, producing gaseous reaction products that prevent the sintering of the spinels. The surface morphology of pigment powders and their composition was studied using a Quanta 3D 200i, FEI Co. scanning electron microscope and a Philips SEM 515 scanning electron microscope equipped with a local energy dispersive X-ray analysis (EDAX). The particle size of the synthesized spinels was approximately 1–5 μm. Colored spinels powders obtained by the SHS process can be used as ceramic pigments. [ABSTRACT FROM AUTHOR]

Integrating nanomaterials like carbon nanotubes (CNTs) and iron oxide (Fe3O4) into epoxy composites has attracted significant interest due to their potential to enhance mechanical properties. This study evaluates the impact of dispersion quality on the mechanical performance of CNT/Fe3O4/epoxy composites, comparing stirring and sonication methods at three different loadings: 0.1, 0.3, and 0.5 wt.%. Tensile testing revealed that sonicated composites consistently outperformed stirred composites, with a significant increase in the elastic modulus and ultimate tensile strength (UTS). However, fracture strain decreased in both composite types compared to pure epoxy, with sonicated composites experiencing a more significant reduction than stirred composites. These results underscore the importance of high-quality dispersion for optimizing mechanical properties. [ABSTRACT FROM AUTHOR]

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Introduction: Atrial fibrillation (AF) is the most common arrhythmia. Catheter ablation is a successful rhythm control strategy in paroxysmal AF, but it has demonstrated dramatically lower AF-free survival rates in patients with persistent AF. In recent years, myriad novel rhythm control strategies have been developed, each with the promise of improved persistent AF ablation success. Areas covered: This review discusses multiple novel techniques and approaches to persistent AF. Authors identified relevant papers by searching PubMed and Google Scholar databases and considered all papers identified, regardless of publication date. It begins by discussing recent advances in electrogram analysis that yielded improved AF-free survival following persistent AF catheter ablation. Next, it discusses several trials revealing the shortcomings of MRI in guiding persistent AF ablation. Finally, it discusses one nascent technique (Vein of Marshall ablation) and technology (AI-assisted electrogram analysis) who have shown promise in improving persistent AF ablation. Expert opinion: In the authors' expert opinions, upcoming persistent AF ablations will utilize a stepwise approach of (1) ensuring PV isolation, (2) Vein of Marshall ablation and (3) AI-assisted ablation to optimize future persistent AF ablation outcomes. This approach systematically addresses arrhythmogenic sources beyond the pulmonary veins, the historical treatment target. [ABSTRACT FROM AUTHOR]

Shear thickening fluids (STF) represent stabilized and concentrated colloidal suspensions, wherein hard nanoparticles are dispersed within a liquid medium (polymer). Under the influence of impact forces, they exhibit non-Newtonian behavior, effectively dissipating energy through shear thickening. The optimization of the dispersion medium's viscosity is critical, as it not only fosters shear thickening but also facilitates proper particle dispersion. This study investigates the impact of graphene oxide (GO) as an additive in STFs, analyzing both static and dynamic rheological properties. STFs were formulated using colloidal silica particles (600 nm) and polyethylene glycol (PEG-200), with varied concentrations of GO particles (0.12–0.5 % w/W). The systems underwent comprehensive analysis concerning steady-state and dynamic-state rheological behavior under diverse conditions. The findings reveal that the inclusion of GO augments both static and dynamic rheological properties, reaching an apex at an optimal concentration of 0.36 % w/W. GO functions as a network builder within the STF, interacting with the existing particle network to create a more robust and interconnected structure. These enhanced properties underscore the potential of the synthesized STF for applications requiring impact resistance. [ABSTRACT FROM AUTHOR]

Generally, fiber with a large mode area is desired for fiber laser and beam delivery applications. But the use of these fiber types is restricted to linear optical applications due to the lower value of the nonlinear coefficient. This paper investigates a single material-based photonic crystal fiber (PCF) with improved optical characteristics, applicable for linear and nonlinear optics. The light propagation in the structure is explored by applying finite element solver-based COMSOL multiphysics software. Five nonlinear optical materials are utilized as background material to get the optimized material with high performance PCF. Using this PCF, the improved optical properties of PCF such as moderate effective mode area of 115.85 μ m 2 , chromatic dispersion, confinement loss of 10 − 6 dB/m, the nonlinear coefficient of 543W − 1 Km − 1 , splicing loss of 2.013 dB, and numerical aperture are numerically analyzed. This single-mode PCF also shows the low bending loss for the bending radius of 7 mm. The amended PCF structure is found to be suitable for high-power fiber laser, supercontinuum generation, wavelength conversion, and slow-light generation. [ABSTRACT FROM AUTHOR]

Lignosulphonate-based azo pigments are synthesized by functionalizing industrial waste lignosulphonate material through a diazo coupling reaction. It has dispersion and metal surface protection function by coating. Aniline, 4,4′-bis(4-aminophenoxy) biphenyl (BAP-Biphenyl), and o-dianisidine were used to synthesize three lignosulphonate-based azo pigments. 1H-NMR, FT-IR, HRMS, and UV spectroscopic methods confirm the pigment formation through the diazo coupling reaction of lignosulphonate and products. By using TGA and DSC analysis, the thermal behaviour of azo pigments was examined. Successive increase in mass also suggests successful diazo coupling reaction. The light scattering technique gives particle size of azo pigments for aniline-azo-LS, BAP-Biphenyl-azo-LS and o-dianisidine-azo-LS were found to be 1578, 2387, and 1917 nm, respectively. Additionally, the negative zeta potential was noticed indicating the pigments' dispersion ability. This dispersible ability was utilized for paint formulation, and chemical resistance of metal coating was observed. The formulation has good mechanical stability, and TGA suggests the thermal stability over 200 °C. This lignin-based functional pigment will find new forms of an environmentally friendly and sustainable method for a cleaner utilization of lignin in metal coatings. [ABSTRACT FROM AUTHOR]

Dust storms and dry haze are an unfavorable meteorological factor for the cities of the Aral Sea Region. The mean annual number of days with haze in Central Asian cities ranges from 10 to 20. Dust makes poorer the aspect of areas, but its impact on urban planning has been incompletely studied and the content of fine dust particles in the air of cities has not been monitored. The Afghan wind (garmsil: fiery, hot, dry wind with dust), which attracts particular attention, is a dust storm that suddenly starts in the deserts of Afghanistan and on the dried bottom of the Aral Sea (it is now called Aralkum (the Turkish kum signifies sand)). This is a real salt desert, containing pesticides and chemicals dangerous for human health. They penetrated rivers as fertilizers used by people and then flowed into the sea. They now cause significant damage to the cities and to the economy of Central Asian countries. Wind transport of dust from natural sources and, as a result, the dustiness of the urban environment are analyzed in this article. This problem is particularly urgent for most large cities in Central Asia, but has not been studied sufficiently. The dust factor is not sufficiently taken into account, when making urban planning decisions even in areas with intensive wind and dust activity, such as the Aral Sea Region, where it is related to natural and climatic conditions. More and more cool agricultural lands are now destroyed and used for building construction in many cities, which may exert a strong effect on the quality of life in the next few years. Not long ago, dustiness was considered only as a factor that creates uncomfortable conditions, but today, it is associated with morbidity and mortality of the population. A high dust content in the air harms landscaped areas, along highways and streets in particular. The protection of buildings from direct sunlight and dust consists in the use of sun protection devices, panels, and ventilated facades. One of the modern trends in architecture consists in the introduction of the technology of kinetic facades, which are formed of elements of different shapes and materials. When the proposed methods are implemented, there is a real opportunity to improve the quality of atmospheric air in cities located in complicated landscape conditions, which will directly affect the improvement of human health. [ABSTRACT FROM AUTHOR]

Purpose. Reducing the dispersion of radar reflections from local objects, with multi-frequency sensing, to solve the problem of orientation by radar reflections from objects. Methodology. Reflections from local objects in the entire frequency range of the radar station (RS) at the same radio engineering position were measured by three independent radars of the same type on different days and at different antenna elevations. The deviation of the radar stations in the position did not exceed 500 meters. Coordinates (azimuth, range) of reflections of several separate local objects were allocated for each radar. The average values of reflections from local objects and their dispersion in the frequency range were calculated. Using various algorithms, individual frequencies were sampled and the reflected signals were averaged at these frequencies. The decrease in the dispersion of the reflected signal from the number of frequencies at which reflections were measured and from the algorithm for selecting these frequencies was investigated. Findings. Averaging the values of reflections from local objects for several frequencies leads to a decrease in dispersion and, as a result, to a more accurate correspondence of the reflected signal level to the geometric size of the local object. The variance decreases most rapidly for a small number of frequencies selected for averaging when selecting frequencies located in an interval of at least 1% relative to each other. Originality. To solve the problem of orientation based on radar reflections from local objects, it is necessary to identify the landmarks selected on a digital terrain model. Due to the fact that local objects (hills) are a collection of many reflectors falling into the allowed volume of the radar, with different levels of reflections and random phases, there may not be radar reflection from a local object at a certain frequency, or it may be very small. In order to unambiguously identify all landmarks, measurements must be carried out at several frequencies. The work has established how many frequencies measurements should be performed at and on what principle these frequencies should be selected. Practical value. The advent of digital terrain models made it possible to solve the problem of terrain orientation by comparing radar reflections from local objects with reflection models based on digital terrain maps. Radar reflection models use mathematical expectations of reflection values, unlike real reflections, which have random deviations in signal levels depending on the operating frequency. Reducing the variance of these deviations increases the accuracy of identifying characteristic local objects (landmarks) used to orient the radar in the absence of data from satellite navigation systems. [ABSTRACT FROM AUTHOR]

On-chip light generation in the mid-infrared (mid-IR) region of the electromagnetic spectrum is gaining considerable attention due to its various potential applications in free-space communication, mid-IR spectroscopy, sensing, and thermal Imaging. In this work, we have designed a dispersion-engineered silicon nitride (SiN)-coated tellurium oxide (TeO2) hybrid waveguide on silica (SiO2) substrate with barium fluoride (BaF2) as cladding for nonlinear applications. Strong modal confinement, broad dispersion characteristic, and high nonlinearity were achieved in the proposed hybrid waveguide design, which are important features for obtaining desired nonlinear applications. Through numerical simulations, we found that the dispersion curve is nearly flat within the dispersion range of −40.60 ps/nm/km to 33.15 ps/nm/km for a spectral bandwidth of 1.55–4.25 µm with a zero-dispersion wavelength (ZDW) around 1.80 µm, which is suitable for generating nonlinear effects such as four-wave mixing, self-phase modulation, and Raman scattering. Such types of on-chip hybrid waveguide devices can be pumped using a commercially available fiber laser operating at a wavelength of 2 µm. The design of the hybrid waveguide was optimized to achieve very low modal confinement loss ranging from 0.1 × 10−4 to 35 dB/cm, with a spectral bandwidth of 1.5–4 µm. Additionally, a high nonlinear coefficient value of 1372 W−1 km−1 was achieved at a pumping wavelength of 1.5 µm in hybrid waveguide. The results of such hybrid waveguides can be helpful to experimentalists working in this field for developing nonlinear hybrid waveguide devices. These nonlinear hybrid waveguide devices have potential nonlinear applications, including four-wave mixing, Raman scattering, and supercontinuum spectrum spanning the near-IR to mid-IR. Further, the on-chip hybrid waveguide structure can be significantly help to expand the functionality of future photonics integrated circuits. [ABSTRACT FROM AUTHOR]

Due to the presence of many flammable substances in the working environments of the petrochemical industry, anticorrosive conductive coatings need to be used on metal equipment to avoid safety accidents like fires. However, existing conductive solvent-based coatings are volatile when exposed to flammable and toxic organic solvents. Thus, in this work, a series of eco-friendly anticorrosive waterborne polyurethane (WPU) composites with multi-walled carbon nanotubes (MWCNTs) were prepared via a low-cost and practical process; the dispersion of MWCNTs was revealed when present in different amounts, and the mechanism behind the conduction of WPU composites was determined. We concluded that low amounts of MWCNTs were well dispersed, generating a conductive network, and the WPU composite was not entirely covered by the MWCNT particles, so the electrical conductivity in certain parts of the coating was good. When the content of MWCNTs was excessive, some stretched MWCNTs dispersed to the top of the composite and many MWCNTs agglomerated at the bottom. Additionally, when the content of MWCNTs was increased, the electrical conductivity, corrosion resistance, and adhesion strength of the WPU composite decreased. Our results could provide a theoretical foundation for the preparation of anticorrosive conductive waterborne composites for protecting equipment in the petrochemical industry. [ABSTRACT FROM AUTHOR]

Sludge ceramsite (SC) can be utilized as a lightweight aggregate in concrete, especially in external wall materials, due to the increasing volume of polluted sludge, which contributes to water system deterioration and poses greater threats to human health. The influence of the fresh mortar's slump flow on the dispersion of ceramsite was studied. The ultrasonic sound velocity, capillary water absorption rate, compressive strength, and coefficient of variation (CV) were measured in this study. Thermogravimetric (TG) analysis, ultra depth-of-field microscope scanning, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) were used to analyze the performance mechanism of the ceramsite concrete. The results indicated that adding SC could reduce the fluidity of the fresh concrete, with a reduction by rates of up to 2.04%. The addition of WRA could improve the fluidity by rates of up to 60.77%. The relationship between the ultrasonic sound speed and the increasing fluidity could be deduced as a negative correlation. The water absorption was negatively correlated with the compressive strength. The concrete with a slump flow of 12.35 and 12.5 cm reached the maximum compressive strength, which had the lowest water absorption, and demonstrated internal homogeneity. The optimum slump flow was 12.35 and 12.5 cm. With the slump flow of 12.5 cm, the corresponding CV was the lowest, showing the optimum SC's dispersion. Through TG, XRD, and SEM analyses, it was verified that the addition of 0.6% WRA promoted the hydration of cement. In addition, SC increased the hydration products. [ABSTRACT FROM AUTHOR]

Fiber optic research continues to develop due to the need for fast information technology. The input signal in an optical fiber is in the form of a soliton wave that propagates in the fiber with a balanced index of refraction, dispersion, and diffraction. Fiber optics may lose some of the signal over time if they solely use a nonlinear refractive index. This study aims to examine into the dynamics and decoherence of multi-peak solitons caused by electromagnetic signal attenuation and potential trap in the propagation via optical fibers. The methods used start with the stationary solution of the nonlinear Schrödinger Cubic Quintic equation, the Newton-Raphson method, and the fourth-order Runge-Kutta. In stationary solutions, the p (state energy) and ρ (Lèvy index) values affect the number, pulse width, and height of soliton peaks. Increased p and ρ values lead to increased instability, causing the data transmitted into the optical fiber to collapse and become unreadable by the receiver. In the excited state (p > 0), the decoherence phenomenon occurs and causes wave instability and destruction. In term of energy intensity, a stable form of transmission in the ground state has a pattern of continuously weakening, decreasing, and smoothing, while in the excited state there is a spike in the intensity of the electromagnetic wave. Based on this study, multi-peak solitons can only be applied for propagation distances, which tend to be short due to their dynamics and decoherence.

Introduction/purpose: Fractured formations recently gained significant interest as a landscape for securing both energy and groundwater demands, However, the dual role of fracture in transporting fluids and contaminants underscores the need for further investigations to mitigate the impact on human health. This study aims to numerically investigate the combined effect of particle density and flow velocity on their transport and deposition in different fracture orientations. Methods: A 2D particle tracing simulation was implemented accounting for drag and gravity forces on a smooth fracture. The derived particle numbers under the studied scenario e.g., fracture orientation, particle density, and flow velocity, were fitted to a 1D advection-dispersion equation with a deposition term. Results: The model elucidated that both particle densities yielded an increase in the normalized concentration in non-horizontal scenarios as the fracture orientation angle increased. The overall increment led to an observed decrease in the deposition coefficients and was associated with an increase in the dispersion coefficients. Hence the effect was more pronounced for denser particles where gravitational settling dominated, particularly in horizontal fractures. Less dense particles (1.05 g/cm³) were more strongly influenced by hydrodynamic forces, exhibiting lower overall deposition and dispersion across all fracture orientations. Additionally, increased flow velocity enhanced mechanical mixing and amplified dispersion and deposition coefficients. Conclusion: The findings demonstrated a clear dependency on the combined effect of fracture orientation, particle density, and flow velocity. These valuable insights into particle transport mechanisms in fractured media have applications in subsurface flow, contaminant migration, and reservoir engineering.

Background. The using of mirror asymmetric chemical compounds for doping quartz makes it possible to metamaterial creation that has the chirality property. In such a compositional structure, unusual effects may arise when interacting with an optical wave. Aim. We calculate the transmission and reflection of a linearly polarized optical wave through a multilayer structure consisting of two doped quartz glasses separated by two air gaps. Methods. Based on a homogeneous mathematical model of a chiral metamaterial, taking into account the dispersion of the dielectric constant and the chirality parameter based on the matrix method, a system of linear algebraic equations is obtained for the complex reflection and transmission coefficients of an electromagnetic wave of linear polarization. Results. An analysis of the frequency and angular characteristics of the modules of the reflection and transmission coefficients was carried out at various values of the quartz doping level. It is theoretically predicted that at some wavelengths, most of the incident optical energy can be concentrated in the air gaps of the multilayer structure. Conclusion. The data obtained as a result of calculations can be used in the development of planar structures for frequency-selective concentration of energy in the visible and infrared spectrum based on quartz glasses doped with chiral chemical compounds.

Abstract Particle tracking (PT) is a popular technique in microscopy, microfluidics and colloidal transport studies, where image analysis is used to reconstruct trajectories from bright spots in a video. The performance of many PT algorithms has been rigorously tested for directed and Brownian motion in open media. However, PT is frequently used to track particles in porous media where complex geometries and viscous flows generate particles with high velocity variability over time. Here, we present an evaluation of four PT algorithms for a simulated dispersion of particles in porous media across a range of particle speeds and densities. Of special note, we introduce a new velocity-based PT linking algorithm (V-TrackMat) that achieves high accuracy relative to the other PT algorithms. Our findings underscore that traditional statistics, which revolve around detection and linking proficiency, fall short in providing a holistic comparison of PT codes because they tend to underpenalize aggressive linking techniques. We further elucidate that all codes analyzed show a decrease in performance due to high speeds, particle densities, and trajectory noise. However, linking algorithms designed to harness velocity data show superior performance, especially in the case of high-speed advective motion. Lastly, we emphasize how PT error can influence transport analysis.

Purposes For improving the mechanical properties of GO incorporated cement paste, two types of nano-silica (crystalline and amorphous) and coal-bearing metakaolin (CMK) were used seprately to improve GO dispersion in cement paste. Methods UV-vis spectrophotometry was used to investigate the effects of ultrasound time and different dosages of amorphous nano-silica (ANS) and crystalline nano-silica (CNS) on the dispersion of GO in saturated calcium hydroxide solution. The effects of different particle materials on GO dispersion were characterized by using compressive strength results. The dehydration and decomposition processes of various phases of hydration products were observed by thermogravimetric (TG) analysis, and the effect of adding different particle materials and GO on the pore structure of cement paste was analyzed by mercury intrusion porosimetry (MIP). Findings According to UV-vis spectroscopic study, when the contents of ANS and CNS were 2% and 1.5% by weight of cement, respectively, GO dispersion in saturated Ca(OH)2 solution is improved greatly. Compared with two nano-silicas, CMK is more effective to improve the compressive strength of GO incorporated cement paste. At the age of 28 d, the flexural strength and compressive strength of the cement paste incorporated with 4% CMK and 0.03% GO are 26.93% and 30.41%, respectively, higher than those of a plain cement paste sample. The results of TG and MIP tests showed that the pozzolanic reaction of CMK can effectively refine the pore structure of cement paste, improve GO dispersion, and enhance the bonding between hydration products and GO, which is the main reason why CMK can effectively improve the mechanical properties of GO incorporated cement paste.

This study reveals the dynamics of short optical pulses in nonlinear media. Then, for the survival of different types of solitary waves in the nonlinear medium, the constraint relations to the physical parameters and chirps associated with each of the solitary waves are explicitly shown. We authenticate numerically all those obtained from the analytical method and show the chirping effect is saturative in nature and can be managed by changing coefficients of inter-modal dispersion, stimulated Raman scattering (SRS), and self-steepening effect. We also verify the more operative condition of intermodal dispersion. [ABSTRACT FROM AUTHOR]

The Airy phase is the frequency at which group velocity of a surface acoustic wave (SAW) attains a stationary value. In turn, a stationary value of the group velocity causes SAW to propagate with a lesser attenuation than at other frequencies. At present, no conditions for the appearance of stationary values of the group velocity are known for dispersive modes of Lamb waves propagating in stratified plates. Herein, the closed form solutions are derived for double zero group velocity (ZGV) belonging to the same Lamb mode. It is also found that the double ZGV leads to the appearance of the Airy phase located between the twofold ZGV. The analysis relies on the Cauchy formalism and the exponent fundamental matrix method. [ABSTRACT FROM AUTHOR]

The paper aims at studying dispersion of elastic waves in a sandwich plate with the parameters, characteristic of aerogel core and hard skin layers, typical for aerospace applications including optimal design of fuselage structural components. The proposed approach relies on multiparametric analysis, taking into account the effect of strong transverse inhomogeneity. It is demonstrated that both an additional low-frequency propagating wave and a slowly decaying evanescent one appear due to a high contrast in geometric and mechanical parameters of the layers. The key findings include the derivation of two-mode asymptotic expansions of the full dispersion relation at the low-frequency limit, as well as elucidation of the non-trivial link between long-wave evanescent and propagating modes. A sophisticated composite nature of the obtained expansions involving various shortened forms is investigated. The range of validity for each of these forms over frequency and wave-number domains is evaluated. Comparison of asymptotic results with the numerical solution of the full dispersion relation is presented. [ABSTRACT FROM AUTHOR]

Aim: The species that compose local communities possess unique sets of functional and ecological traits that can be used as indicators of biotic and abiotic variation across space and time. Body size is a particularly relevant trait because species with different body sizes typically have different life history strategies and occupy distinct niches. Here we used the body sizes of non‐volant (i.e., non‐flying) terrestrial mammals to quantify and compare the body size disparity of mammal communities across the globe. Location: Global. Time Period: Present. Major Taxa Studied: Non‐volant terrestrial mammals. Methods: We used IUCN range maps of 3982 terrestrial mammals to identify 1876 communities. We then combined diet data with data on climate, elevation and anthropogenic pressures to evaluate these variables' relative importance on the observed body size dispersion of these communities and its deviation from a null model. Results: Dispersion for these communities is significantly greater than expected in 54% of communities and significantly less than expected in 30% of communities. The number of very large species, continent, range sizes, diet disparity and annual temperature collectively explain > 50% of the variation in observed dispersion, whereas continent, the number of very large species, and precipitation collectively explain > 30% of the deviation from the null model. Main Conclusions: Climate and elevation have minimal predictive power, suggesting that biotic factors may be more important for explaining community body size distributions. However, continent is consistently a strong predictor of dispersion, likely due to it capturing the combined effects of climate, size‐selective human‐induced extinctions and more. Overall, our results are consistent with several plausible explanations, including, but not limited to, competitive exclusion, unequal distribution of resources, within‐community environmental heterogeneity, habitat filtering and ecosystem engineering. Further work focusing on other confounding variables, at finer spatial scales and/or within more causal frameworks is required to better understand the driver(s) of these patterns. [ABSTRACT FROM AUTHOR]

In this study, the models for the DNA origami lattice will be investigated. Our aim is to theoretically explore the ways of constructing DNA origami. To achieve this goal the DNA origami structure, consisting of nanowires embedded in a host material, will be treated from the perspective of nanowire metamaterial. Surface plasmon polaritons propagating at the interface of air and DNA metamaterial are analyzed. The dispersion relation is attained using the transfer matrix technique and employing continuity conditions of electric fields and their derivatives at the boundary separating two regions. We have concluded that with numerous nanowires into the metamaterial unit, cell frequencies of surface plasmon polaritons are altered to higher frequencies. In this study, we have studied the effect of modifications of the metamaterial, allowing for the shift of the dispersion maps toward higher frequencies. It is possible to obtain the propagation of spoof plasmons mimicking the behavior of surface waves at lower frequencies. All the properties and parameters of the inorganic metamaterials are applicable to study the phenomenon of the organic substances. [ABSTRACT FROM AUTHOR]

Dose and volume metrics to organs at risk are used for evaluation and optimization in radiotherapy planning. However, the numerous choices of metrics can be confusing. In a series of patients treated with hypofractionation and an integrated boost for breast cancer, we aim to determine if a parsimonious selection of representative metrics can be identified. The dosimetries of 42 patients receiving 42 Gy to the breast, with or without nodal irradiation, and 51 Gy integrated boost to tumor bed in 15 fractions were reviewed. For each organ—heart, lungs, and contralateral breast—cumulative dose-volume histograms were used to extract values for 3 basic metric classes: 1. The dose D.yy (Gy) received by yy% of the organ volume. 2. The percentage of organ volume Vrel.xx (%) receiving the dose of xx Gy. 3. The absolute organ volume Vabs.xx (mL) receiving the dose of xx Gy. Two additional classes were considered: • The mean dose (Gy) received by the organ. • The dose standard deviation (Gy) received by the organ. Pearson correlation coefficient R was calculated between pairs of values within each basic class and with the 2 additional classes for each organ. The interquartile ranges of correlations for D.yy, Vrel.xx, and Vabs.xx were as follows: • Heart: 0.90-0.99, 0.50-0.92, and 0.58-0.93. • Ipsilateral lung: 0.81-0.98, 0.35-0.95, and 0.46-0.96. • Contralateral lung: 0.83-0.98, 0.71-1.00, and 0.65-1.00. • Contralateral breast: 0.74-0.97, 0.30-0.92, and 0.45-0.95. The mean dose correlated with all basic classes for the heart and lungs, and with dose D.yy and volumes at Vrel.10-Vabs.10 for the contralateral breast. The standard deviation correlated with Vrel.xx and Vabs.xx for the heart and lungs (R ≥ 0.70). Among the D.yy, D.50 (median dose) correlated with the mean and standard deviation for all organs (R = 0.65-0.96). The mean, standard deviation, and median doses were the preeminent correlators. These statistics appear to be parsimonious representatives of doses to organs. Further studies with other radiotherapy series will be necessary to validate these observations. [ABSTRACT FROM AUTHOR]

Due to the large specific surface area and strong van der Waals force, bulk aggregation of nano- TiO2 immediately occurs when it is mixed with fresh cement mixture, limiting its reinforcing efficiency to cement-based materials. This study proposes a novel strategy to improve the mechanical and photocatalytic properties of cement mortar using nano- TiO2 hydrosol instead of conventional nano- TiO2 powder. Compared with pure mortar, the 28-day compressive and flexural strength of mortar with 0.6% by weight nano- TiO2 hydrosol were enhanced by 51% and 15%, respectively, the water absorption and chloride ion diffusion coefficient were decreased by 21% and 31%, respectively. The observed improvements were attributed to the denser microstructure and enhanced micromechanical properties in the bulk matrix and around interfacial transition zone (ITZ), resulting from the better dispersion of nano- TiO2 hydrosol in alkaline environment. In addition, compared with the mortar with nano- TiO2 powder, the degradation efficiency of Rhodamine B and NO by the mortar with nano- TiO2 hydrosol (0.6% by weight) was enhanced by 18.3% and 17.1% at 28 days, respectively. The enhancement resulted from the higher intrinsic photocatalytic activity and larger exposed surface area of nano- TiO2 hydrosol due to better dispersion. The research outcomes demonstrate the potential of using nano- TiO2 hydrosol in cement mortar to significantly increase the mechanical strength, durability, and photocatalytic activity, which can lead to the development of cement-based constructions with the integrated design of functionality and structure. [ABSTRACT FROM AUTHOR]

Abstract This research is centered on a comprehensive investigation into the impact of turbulence on the movement and dispersion of materials within a three‐dimensional (3D) bedform, specifically when there is a continuous presence of rigid vegetation submerged in the flow. To achieve our research objectives, we conducted extensive velocity measurements within a channel featuring this submerged vegetation. The measurements were carried out using an Acoustic Doppler Velocimeter (ADV). Additionally, our study delved into the intricate structures and turbulent characteristics of the flow, considering the coexistence of submerged vegetation and a 3D gravel pool. This pool featured entrance and exit slopes measuring 3 and 2.5°, respectively. Our experimental setup took place in a straight flume, measuring 14 m in length, 0.9 m in width, and 0.6 m in depth. The flume was equipped with transparent side walls to facilitate observations. Furthermore, our investigation extended to the spatial variations in velocity and turbulence distributions. We analyzed various parameters including turbulence kinetic energy, integral turbulence lengths, dispersion coefficients, and advective transport. The results revealed that integral length scales offer key insights into turbulent eddy behavior. In the presence of vegetation and a 3D bedform, turbulent eddies undergo notable changes, flattening in the longitudinal direction and expanding in the transverse and vertical directions. Moreover, longitudinal advection is notably higher compared to flows without vegetation in a uniform flow or bare channel, especially for z/H > 0.2. This indicates that the presence of vegetation and a 3D bedform leads to an increase in turbulent kinetic energy (k values) that surpasses the reduction in the time‐averaged velocity component (“U”) in the U × k term, thereby enhancing longitudinal advection.

Solubility in penetrating the follicles is the main obstacle in the formulation of hair growth serum preparation with chemicals derived from natural or synthetic materials. Therefore, a delivery system is needed to deliver more chemical compounds into the follicles. Nanoparticles and nanoliposomes are potential chemical compound delivery systems in hair growth serum. Specifically, nanoparticles with a particle size of less than 200 nm can increase the transport of serum chemical compounds into the scalp. The small particle size makes the interaction between atoms and molecules faster and prevents clumping with the repulsive force of dispersed particles. Meanwhile, nanoliposomes with lipids as encapsulation in the delivery of lipophilic or hydrophilic chemical compounds with nanosizes can significantly increase serum diffusion on the scalp.

The dispersion behaviour of the finite element method, applied to the treatment of stress wave propagation tasks in an elastic solid continuum, is reviewed and complemented with the authorsâ contributions in the field, along with substantial details of finite element technology. It is shown how finite element dispersion disqualifies to a certain extent the stress wave propagation modelling and, as such, cannot be completely eradicated. The paper, however, reveals the ways how the dispersion effect (actually, modelling errors) could be minimized. The effects of spatial and temporal dispersions of the finite element method are treated. 1D and 2D linear and quadratic finite elements and their suitability are analysed for use with implicit and explicit integration methods. Historical as well as new, up-to-date approaches are also reviewed. The paper closes with recommendations for values of mesh size and timestep size, mass matrices and direct time integrations with respect to dispersion errors in finite element modelling of elastic wave propagation problems in solids.

Background: Electrogram dispersion identifies putative atrial fibrillation (AF) drivers in first time ablation procedures, with high acute termination rates and long-term outcomes akin to extensive ablation approaches. Its use in a population that had undergone repeat ablation is unknown, particularly where the pulmonary veins are already isolated. Objective: This purpose of this study was to assess electrogram dispersion mapping during repeat ablation procedures for persistent AF. Methods: One hundred sixty-seven patients from the United Kingdom and Denmark, all with persistent AF recurrence after prior ablation procedure(s), were mapped using a five splined catheter for electrogram dispersion before ablation. Areas were manually tagged on biatrial electroanatomic maps and ablated once pulmonary vein isolation was confirmed or reisolated if required. All patients had 12-month continuous monitoring, with most of the cohort having follow-up beyond 24 months. Results: Of the 167 patients [53 (32%) female; mean age 66 ± 8 years; mean left atrial (LA) diameter 4.8 cm; mean ejection fraction 53%], 108 had pulmonary veins already isolated. Dispersion sites occurred in both atria (3.2 LA, 1.4 right atrium). Acute termination to sinus rhythm occurred in 71 (42%) of the cohort patients, with a further 73 (44%) terminating to atrial tachycardia/flutter. At 12-month follow-up, 95% of patients were free of AF, with 74% overall freedom from all atrial arrhythmias. Heart failure and severely enlarged LA predicted recurrence, and termination to sinus improved freedom from all atrial arrhythmias. Conclusion: Dispersion mapping is a promising approach at repeat ablation procedures for persistent AF, with high acute termination rates and good clinical outcomes. Further prospective randomized trials are needed to evaluate this approach in a population that had undergone repeat ablation.

In material science, converting waste into nanomaterials by green technologies highlights the interest in producing sustainable carbon nanomaterial (SCN). This study first-ever utilized tyre-char as a Nano-Structure Pyrolytic Carbon (NSPC) to develop electrically conductive composites. Unlike other carbon nanomaterials, the efficiency of NSPC particle as an SCN in developing electrically conductive composites was investigated in terms of dispersion, mechanical, water absorption, electrical resistivity, and microstructure. The results of sedimentation and zeta potential (−19 mV) showed the excellent dispersion of NSPC particle in water with the combined effect of superplasticizer and ultrasonication. The compressive (40.37%) and flexural strength (10.76%) than that of plain cement mortar composite (CMC) is achieved with 2 wt.% and 1.5 wt.% of NSPC particle, respectively. The water absorption rate and volume of permeable voids were reduced, exhibiting less agglomerations. The percolation zone of AC and DC resistivity of NSPC composite ranges between 1 and 2 wt.%, and the established percolation threshold is at 2 wt.%. XRD analysis showed C-S-H formation consistently increased with curing age, and HR-SEM with EDAX analysis exhibits the dense microstructure and well-distributed NSPC particle at the nanoscale. These experimental outcomes significantly enhanced the reliability and provided a framework for tailoring NSPC particle as SCN for developing electrically conductive composite.

Background. Taking into account temperature, soil composition, surface roughness and the dependence of effective dielectric constant on frequency allows a more accurate assessment of soil moisture and other important parameters, which can be used in various fields such as agriculture, geology, ecology and hydrology. Aim. In this work, we calculate the reflection of a linearly polarized electromagnetic wave from wet soil, taking into account such physical factors as heterogeneity of soil structure, surface roughness and dispersion. Methods. Based on a heterogeneous mathematical model of wet soil, taking into account the dispersion of the dielectric constant of water and surface roughness, expressions are derived for the complex reflection coefficients of electromagnetic waves of vertical and horizontal polarization. Results. The model of loose wet soil with the standard deviation of roughness on the surface was chosen as the object of study. An analysis of the frequency and angular characteristics of the modules of the reflection coefficients was carried out at a fixed level of soil moisture. Conclusion. The data obtained as a result of the calculations is a valuable tool for further improving methods of remote sensing of the Earth and contributes to the development of new technologies for monitoring soil parameters using unmanned aerial vehicles, which opens up prospects for more accurate and efficient analysis of the state of land resources and ecosystems.

In 2020, Apple incorporated a LiDAR sensor system into its smart devices, being the first to offer the laser scanning technology to the general consumer. This article investigates how a low-cost LiDAR scanning system integrated into Apple devices performs in comparison to professional geodetic terrestrial laser scanners. In addition to providing a brief overview of the functionality of the measurement system within Apple devices, a comprehensive literature review was conducted. Various authors have examined the system either in comparison to other spatial data capture methods or in studies of its applicability across different fields. In this article, we examined the geometric quality of the lidar scanning system embedded in the Apple iPad Pro device for the purpose of 3D modeling of indoor building spaces. We conducted experiments in a smaller (~1 m) and larger (~10 m) test field and evaluated the geometric quality of the captured data. The findings indicate that the Apple system cannot achieve relative positional accuracy better than 10 cm and is primarily suitable for creating informative 3D representations.

In this study, the vehicular air pollution from the Nairobi Expressway corridor was estimated by simulation using AERMOD dispersion model. The Vehicle Kilometer Travelled (VKT), emission factors, and traffic data were used to estimate the pollutants from vehicular traffic.. The highest modelled 24-hour and annual concentrations of PM2.5 were 0.274 µg/m3 and 0.152 µg/m3, whereas the highest 24-hour and annual concentrations of PM10 were 0.405 µg/m3 and 0.225 µg/m3, respectively. The maximum 24-hour and annual concentrations of Total Volatile Organic Compounds (TVOCs) were 20.8 µg/m3 and 11.5 µg/m3, respectively, whereas the maximum 8-hour and annual concentrations of carbon monoxide (CO) were 319 µg/m3 and 177 µg/m3, respectively. The highest modeled 24-hour and annual concentrations of NO2 were 28.2 µg/m3 and 15.7 µg/m3, respectively. The 24-hour average measured TVOCs values showed that Nairobi expressway traffic contributed 3.5 percent to the measured TVOCs concentration value, but CO accounted for 55 percent of the measured value. According to the simulated PM2.5 and PM10 concentration values, Nairobi expressway traffic contributed 1.1 and 1.6 percent, respectively, to the 24-hour average measured concentration levels.

We propose a three-dimensional model implementing a self-consistent field (SCF) mathematical formulation to predict the equilibrium orientation and morphology of grafted nanoparticles (NPs) in a polymer, based on two- and multibody interactions developed among them. First, we investigate the potential of mean force (PMF) between two spherical polystyrene-grafted silica NPs in a polystyrene melt as a function of the matrix-to-grafted chain length ratio and, more importantly, of the distribution of grafting points on their surfaces. While the most common assumption when performing such calculations is an equidistant distribution of grafting points on the surfaces of the NPs, we demonstrate here that the pattern of grafting plays an essential role in the equilibrium orientation and shape assumed by the particles inside the polymer matrix. In equidistant grafting, the role of grafting density is dominant, but, when grafting the chains irregularly, the same number of grafted chains distributed differently can significantly affect the self-assembly tendencies of the particles and the thermodynamic behavior of the composite system. Next, we calculate the free energy of a system of multiple equidistantly grafted nanoparticles exposed to a melt when they are arranged in a simple cubic (SC), body-centered cubic (BCC), and face-centered cubic (FCC) lattice as a function of their spatial density. We minimize the free energy with respect to nanoparticle density to impose the condition of thermodynamic equilibrium. Among the three arrangements, the FCC/SC is the most/least stable configuration. The three-dimensional SCF methodology proposed herein addresses all possible degrees of freedom for the molecular-level design of both stable dispersions and self-assembled nanocomposite morphologies with tailor-made properties. It offers a cost-effective approach to creating high-value nanocomposite materials such as polymer-matrix nanocomposites in the rubber industry as well as "particle-solids," the latter combining toughness with good optical properties. [ABSTRACT FROM AUTHOR]

It is known that the dispersion of colloidal particles in porous media is determined by medium structure, pore-scale flow variability and diffusion. However, much less is known about how diffusiophoresis, that is, the motion of colloidal particles along salt gradients, impacts large-scale particle dispersion in porous media. To shed light on this question, we perform detailed pore-scale simulations of fluid flow, solute transport and diffusiophoretic particle transport in a two-dimensional hyper-uniform porous medium. Particles and solute are initially uniformly distributed throughout the medium. The medium is flushed at constant flow rate, and particle breakthrough curves are recorded at the outlet to assess the macroscopic effects of diffusiophoresis. Particle breakthrough curves show non-Fickian behaviour manifested by strong tailing that is controlled by the diffusiophoretic mobility. Although diffusiophoresis is a short-time, microscopic phenomenon owing to the fast attenuation of salt gradients, it governs macroscopic colloid dispersion through the partitioning of particles into transmitting and dead-end pores. We quantify these behaviours by an upscaled analytical model that describes both the retention and release of colloids in dead-end pores and the observed long-time tailings. Our results suggest that diffusiophoresis is an efficient tool to control particle dispersion and filtration through porous media. [ABSTRACT FROM AUTHOR]

Graphene has been considered an ideal reinforcement in aluminum alloys with its high Young's modulus and fracture strength, which greatly expands the application range of aluminum alloys. However, the dispersion of graphene and the interfacial reaction between graphene and the aluminum matrix limit its application due to elevated temperature. Friction stirring processing (FSP) is regarded as a promising technique to prepare metal matrix composites at lower temperatures. In this paper, FSP was used to prepare graphene-nanoplates-reinforced aluminum composites (GNPs/Al). The corresponding effects of the process parameters and graphene content on GNPs/Al were thoroughly studied. The results showed that plastic strain, heat input, and graphene content were the key influencing factors. Large degrees of plastic strain can enhance the dispersion of graphene by increasing the number of stirring passes and the ratio of stirring to welding velocity, thereby improving the strength of GNPs/Al. Low heat input restricts the plastic flow of graphene in the matrix, whereas excessive heat input can promote interfacial reactions and lead to the formation of a more brittle phase, Al4C3. This is primarily associated with the stirring velocity and welding velocity. High graphene content levels can improve the material strength by refining the grain size, improving the load transfer ability, and acting as a precipitate to prevent dislocation movement. These findings make a contribution to the development of advanced aluminum alloys with graphene reinforcement, offering broader application potential in industries. [ABSTRACT FROM AUTHOR]

Recent advancements in mass production of graphene powders utilize less energy‐intensive methods and milder chemicals compared to traditional lab‐scale techniques. This can influence the properties of the resulting graphene particles. This study investigates the effect of mass‐produced graphene powder on the curing and rheological properties of a resin transfer molding (RTM) grade unsaturated polyester resin. An objective dispersion quantification method was established to track the dispersion state of the nanocomposite throughout the curing process. The findings reveal that the graphene powder accelerated the curing evidenced by a shift in the peak temperature and gel point towards lower values. The sample containing 1 wt.% graphene exhibited remarkable dispersion stability with only 7.1% decrease by gelation. The resin matrix's low viscosity enhanced graphene particles mobility, while its fast‐curing nature allowed less time for agglomeration. Highlights: Characterization of unsaturated polyester nanocomposites modified with an industrial‐grade graphene powderReal‐time in‐situ monitoring of graphene's dispersion stateQuantification dispersion analysis for an objective dispersion assessment [ABSTRACT FROM AUTHOR]

The excitation of wave motion by an external source and the interaction of modes inherent to a flow in a dispersive medium are considered. Dispersion is caused by the presence of gaseous bubbles in a liquid. A large variety of steady excited waveforms is possible when the exciting wave is also steady and propagates at a constant velocity. The velocities of the exciter and forced waves may be different. This leads to a variety of non-stationary excitations. [ABSTRACT FROM AUTHOR]

Introduction: Intraindividual variability across a battery of neuropsychological tests (IIV-dispersion) can reflect normal variation in scores or arise from cognitive impairment. An alternate interpretation is IIV-dispersion reflects reduced engagement/invalid test data, although extant research addressing this interpretation is significantly limited. Method: We used a sample of 97 older adult (mean age: 69.92), predominantly White (57%) or Black/African American (34%), and predominantly cis-gender male (87%) veterans. Examinees completed a comprehensive neuropsychological battery, including measures of reduced engagement/invalid test data (a symptom validity test [SVT], multiple performance validity tests [PVTs]), as part of a clinical evaluation. IIV-dispersion was indexed using the coefficient of variance (CoV). We tested 1) the relationships of raw scores and "failures" on SVT/PVTs with IIV-dispersion, 2) the relationship between IIV-dispersion and validity/neurocognitive disorder status, and 3) whether IIV-dispersion discriminated the validity/neurocognitive disorder groups using receiver operating characteristic (ROC) curves. Results: IIV-dispersion was significantly and independently associated with a selection of PVTs, with small to very large effect sizes. Participants with invalid profiles and cognitively impaired participants with valid profiles exhibited medium to large (d =.55–1.09) elevations in IIV-dispersion compared to cognitively unimpaired participants with valid profiles. A non-significant but small to medium (d =.35–.60) elevation in IIV-dispersion was observed for participants with invalid profiles compared to those with a neurocognitive disorder. IIV-dispersion was largely accurate at differentiating participants without a neurocognitive disorder from invalid participants and those with a neurocognitive disorder (areas under the Curve [AUCs]=.69–.83), while accuracy was low for differentiating invalid participants from those with a neurocognitive disorder (AUCs=.58–.65). Conclusions: These preliminary data suggest IIV-dispersion may be sensitive to both neurocognitive disorders and compromised engagement. Clinicians and researchers should exercise due diligence and consider test validity (e.g. PVTs, behavioral signs of engagement) as an alternate explanation prior to interpretation of intraindividual variability as an indicator of cognitive impairment. [ABSTRACT FROM AUTHOR]

Overgeneralization and a lack of baseline data for microorganisms in high‐latitude environments have restricted the understanding of the microbial response to climate change, which is needed to establish Antarctic conservation frameworks. To bridge this gap, we examined over 17,000 sequence variants of bacteria and microeukarya across the hyperarid Vestfold Hills and Windmill Islands regions of eastern Antarctica. Using an extended gradient forest model, we quantified multispecies response to variations along 79 edaphic gradients to explore the effects of change and wind‐driven dispersal on community dynamics under projected warming trends. We also analyzed a second set of soil community data from the Windmill Islands to test our predictions of major environmental tipping points. Soil moisture was the most robust predictor for shaping the regional soil microbiome; the highest rates of compositional turnover occurred at 10–12% soil moisture threshold for photoautotrophs, such as Cyanobacteria, Chlorophyta, and Ochrophyta. Dust profiles revealed a high dispersal propensity for Chlamydomonas, a microalga, and higher biomass was detected at trafficked research stations. This could signal the potential for algal blooms and increased nonendemic species dispersal as human activities increase in the region. Predicted increases in moisture availability on the Windmill Islands were accompanied by high photoautotroph abundances. Abundances of rare oligotrophic taxa, such as Eremiobacterota and Candidatus Dormibacterota, which play a crucial role in atmospheric chemosynthesis, declined over time. That photosynthetic taxa increased as soil moisture increased under a warming scenario suggests the potential for competition between primary production strategies and thus a more biotically driven ecosystem should the climate become milder. Better understanding of environmental triggers will aid conservation efforts, and it is crucial that long‐term monitoring of our study sites be established for the protection of Antarctic desert ecosystems. Furthermore, the successful implementation of an improved gradient forest model presents an exciting opportunity to broaden its use on microbial systems globally. [ABSTRACT FROM AUTHOR]

Single-isotherm n(p, T90) results are reported for the gases Ar, N2, H2O, and D2O at vacuum wavelength λ = 1542.383 (1) nm. The argon and nitrogen isotherms were measured near 303 K; the water isotherms were measured near 373 K. Combined with the two previous articles of this series, the present results beget several insights via dispersion analyses. The argon result is highly consistent with static measurement plus ab initio calculation of dispersion polarizability. The nitrogen result is nominally consistent with one recent experiment and the dipole oscillator strength distributions, but the present work offers a refined estimate of the molar refractivity at optical wavelengths. For ordinary and heavy water, the dispersion trend is nominally consistent with existing liquid measurements. However, water's absorption features in the near-infrared preclude a reliable comparison of the present result with literature. [ABSTRACT FROM AUTHOR]

The traditional craft villages in Vietnam in general and in Bac Ninh province in particular have been exposing many negative impacts on the environment. The heavy metal-rich wastes from the metal recycling casting craft villages in the field of metal recycling and metal casting are causing severe heavy metal pollution not only to the air, soils, and sediments but also to the groundwater resources. In Da Hoi iron recycling craft village in Chau Khe ward, Tu Son town, Bac Ninh province, Vietnam, the Holocene aquifer is exposed to the Ngu Huyen Khe River's sediments contaminated with heavy metals Lead, Cadmium, Nickel, and Zinc. Freundlich isotherm parameters of the Holocene aquifer have been selected for finite element modeling of heavy metal transport with high temporal and spatial varying retardation factors to get reliable quantitative heavy metals' distribution in depth and time. Initial and boundary conditions have been augmented to be established. The retardation factors of the advection and dispersion transport in the Holocene aquifer for heavy metals Pb, Zn, Cd, and Ni are very highly none-linear and very much varying in time and space: 8.7–66.4 for Pb, 2.0–12 for Zn, 1.7–4.8 for Cd and 1.1–5.9 for Ni. The results of the numerical modeling show that heavy metal transport in the Holocene aquifer is very fast and the entire aquifer thickness has equilibrium aquifer formation and aquifer water heavy concentrations after around 2–2.5 years for Cd and Ni, around 4 years for Zn and around 27 years for Pb. The heavy metals' fluxes from the Holocene aquifer to the Pleistocene aquifer are maximal and more or less constant from the equilibrium time and would cause severe contamination of the Pleistocene aquifer. [ABSTRACT FROM AUTHOR]

Anomalous guided waves appearing at a non-semisimple degeneracy of the fundamental matrix are observed and analyzed in the framework of the Cauchy sextic formalism. The non-semisimple degeneracy condition is explicitly constructed for the most general case of Lamb waves propagating in a traction-free layer with arbitrary elastic anisotropy. A new type of dispersion equation and the corresponding dispersion solution are obtained. The connection with surface waves of the non-Rayleigh type is discussed. [ABSTRACT FROM AUTHOR]

Highlights Graphene's unique characteristics have piqued a great deal of academic and industrial curiosity. Its potential as a composite material reinforcement is the subject of intensive study. When it comes to reinforcing fillers, graphene stands head and shoulders above the rest due to its remarkable thermal, electrical, and mechanical capabilities. Epoxy resin, is widely used in a variety of industrial processes, including the production of laminates, coatings, and composites due to its processing simplicity, its tenacious adhesion to substance types, and its resistance to chemical agents. The performance of the composite relies on how the graphene nanoparticles are dispersed and interact with the polymer. Graphene‐enhanced composites use a variety of methods, such as dispersing graphene in a polymer matrix, to incorporate the material into its structure. Composites find their most common use in competitive situations settings where elements like mass and mechanical characteristics are prioritized over economic consideration. The use of carbon fiber and other state‐of‐the‐art fibers in composite structures is becoming increasingly common. This study aims to conduct an experimental analysis of a graphene‐reinforced epoxy composite's flexural and tensile properties containing varying amounts graphene. In this study, a multi‐step procedure was designed to ensure uniform distribution graphene. The results of a study on tensile and flexural strength showed good enhancement at a weight percent of G0.6% compared to clean epoxy. The novel method of manufacturing of graphene enhanced composite sheet. The lower weight fraction of graphene gives good results in terms of mechanical properties. Improvement in tensile strength by 53.35% and flexural test occurs of 8.04% in stress value at 0.6 wt% addition of Graphene Tensile Modulus and flexural modulus improvement of 76.26% and 16.87% respectively at 0.6% of wt. of graphene Fourier transform infrared spectroscopy showed promising results which shows existing of functionalized groups of amines. Scanning electron microscopy revealed graphene's interaction with the polymer matrix at the interface. [ABSTRACT FROM AUTHOR]

Comblike polycarboxylate superplasticizers (PCs) have been widely used as construction and building materials by means of high fluidity and fine dispersibility via electrostatic repulsion and steric hindrance. The conventional PCs are usually synthesized by free radical polymerization, which limit to understand and even distort the structure-property relationship due to the random molecular structure and the broad polydispersity. In this work, polycarboxylate ether superplasticizers of acrylic acid (AA) and ethylene glycol monovinyl PEG (EPEG) with controlled structure were prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. The resultant copolymers (denoted as EPCs) were characterized by FT-IR, 1H NMR and GPC spectroscopy. The effect of actual acid/ether (AA/EPEG) ratio on the adsorption capacity and dispersion ability of EPCs in cement paste were deeply investigated. These results demonstrate that the dispersibility of EPCs with controlled molecular weights and comparatively narrow polydispersity indexes (PDI=1.2–1.4) strongly depends on the acid/ether ratio. With an increase of the feed molar ratio of AA/EPEG from 4∶1 to 8∶1 , the molecular weight and their distribution of EPCs increases accordingly. In addition, the adsorption capacity and dispersion property of EPCs to cement are densely related to the molecular structure and composition and superior to that of conventional PC analogues. A possible mechanism was proposed that EPCs can act uniformly on the surface of cement particles due to the well-defined molecular structure and well-distributed molecular weight, which is different from the conventional PCs, which will offer the fundamentals of design and synthesis for polycarboxylate superplasticizers with controlled structures. [ABSTRACT FROM AUTHOR]

We have developed a new type of hybrid-structured Photonic Crystal Fiber (H-PCF) that includes a sectored core-cladding configuration. It's composed of a cladding with a regular circular sectored lattice structure and a core with a hexagonal sectored lattice structure. To extensively design, analyze, and calculate the fiber's properties, the finite element method has been used. The results provide validation for the superior performance of this novel fiber design. It simultaneously achieves extremely low effective material loss and confinement loss equal to 0.0145 cm⁻1 and 1 × 10⁻14 cm⁻1, respectively, at the 1 THz frequency. Furthermore, the fiber demonstrates nearly zero flattened dispersion (− 0.45 ± 0.55 ps/THz/cm) across the 0.9–1.3 THz frequency range, along with important attributes such as a large core power fraction (50%) and an effective area of 5 × 105 µm2. The suggested PCF design is practical for manufacturing utilizing currently available technologies. Moreover, the proposed PCF design, employing common structured regions in the circular and hexagonal patterns for the sectored cladding and core regions, respectively, is feasible for fabrication using existing technologies. Overall, this H-PCF shows significant potential for various THz applications, especially in THz wave guidance. [ABSTRACT FROM AUTHOR]

In order to elucidate ventilation and exhaust of hydrogen (H2) leaked in a partially open space (room) practically, the effects of outer wind (forced external flow) on them were studied analytically by using a CFD (computational fluid dynamics) code in the room of experimental 'Half-size Hallway model (1/2 Hallway model),' which has a H2 release hole on the bottom, one vent on the roof (Roof vent) and another vent on the side (Door vent): external air flowed in the room from the Door vent and then H2 was discharged outside from the Roof vent. The H2 concentration distribution in the room was divided into two layers at the height of Door vent, with a high concentration layer above it and a low concentration layer below it, forming a stratified interface. When the wind speed blown into the room increased, the combination of the Realizable k-ε turbulence model and the turbulence Schmidt number of 1.0 improved the reproducibility of the analysis results of H2 concentration distribution. The trial analysis suggested that the concern that wind would increase the indoor H2 concentration could be reduced by using the plate with a simple structure in which two plates were crossed on the Roof vent. [ABSTRACT FROM AUTHOR]

The spatial distribution pattern of rural settlements in the Yellow River Basin is scattered and numerous. It is of great significance to study the discrete distribution of rural settlements for achieving high-quality development and promoting rural revitalization strategy. In this paper, we propose an enhanced evaluation model for assessing the spatial distribution dispersion of rural settlements, incorporating the weight of road grade (the road grade refers to the ranking of traffic capacity and importance of a particular type of road, indicating varying levels of time accessibility). We investigate the dispersion characteristics of rural settlements in the Yellow River Basin in 2020, focusing on both county and city scales. Furthermore, we conduct a comprehensive analysis of the spatial differentiation and scale effects of dispersion evaluation outcomes and their driving forces. Our findings reveal the following insights: (1) The road grade significantly influences the dispersion evaluation. When considering road grade in the dispersion calculation, the results align more closely with the actual situation. (2) The dispersion of rural settlements in the Yellow River Basin exhibits a decreasing trend from west to east. Specifically, the dispersion is higher in the upper reaches compared to the middle and lower reaches. Both city and county scales show spatial autocorrelation in dispersion, with a positive spatial correlation observed. High dispersion values cluster in the west, while low values concentrate in the east. Notably, the agglomeration degree is more pronounced at the county scale than at the city scale, highlighting more localized patterns of agglomeration and dispersion. (3) The multiscale geographically weighted regression model emerges as the optimal model for analyzing the driving forces of dispersion. At the city scale, factors such as river density, road density, and rural economy negatively impact dispersion. However, at the county scale, average elevation and rural economy positively affect dispersion, whereas river density, road density, and rural population density have a negative influence. By incorporating the weight of road grade into our evaluation model, we provide a more nuanced understanding of the spatial distribution dispersion of rural settlements in the Yellow River Basin. Our findings offer valuable insights for policymakers and planners seeking to optimize rural settlement patterns and promote sustainable rural development. [ABSTRACT FROM AUTHOR]

In the present investigation, a total of 108 combinations of ionic liquids (ILs) were screened using the conductor-like screening model for real solvents (COSMO-RS) with the aid of six cations and eighteen anions for the extraction of succinic acid (SA) from aqueous streams through dispersive liquid–liquid microextraction (DLLME). Using the screened ILs, an ionic liquid-based DLLME (IL-DLLME) was developed to extract SA and the role of different reaction parameters in the effectiveness of IL-DLLME approach was investigated. COSMO-RS results suggested that, quaternary ammonium and choline cations form effective IL combinations with [OH¯], [F¯], and [SO42¯] anions due to hydrogen bonding. In view of these results, one of the screened ILs, tetramethylammonium hydroxide [TMAm][OH] was chosen as the extractant in IL-DLLME process and acetonitrile was adopted as the dispersive solvent. The highest SA removal efficiency of 97.8% was achieved using 25 μL of IL [TMAm][OH] as a carrier and 500 μL of acetonitrile as dispersive solvent. The highest amount of SA was extracted with a stir time of 20 min at 300 rpm, followed by centrifugation for 5 min at 4500 rpm. Overall, the findings showed that IL-DLLME is efficient in extracting succinic acid from aqueous environments while adhering to the first-order kinetics. [ABSTRACT FROM AUTHOR]