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In the present work, based on the traditional air dense medium fluidized bed (ADMFB), the constant gas velocity was substituted with pulsating velocity to propose pulsating fluidized bed (PFB) to investigate the distinct advantages in separating the fine coal particles in PFB over ADMFB. In this regard, the two-fluid model (TFM) was used to study the formation of bubbles, the distribution of density, and the gas-solid motion in PFB. The simulation results showed that lower bed height could decrease the energies of collision and mergers. The reason why the diameter of bubbles in PFB was much smaller than ADMFB was that the pulsating mechanism could effectively cut off the aggregation channels of gas below the lower pressure domain of bubbles. Moreover, the dense medium particles presented the upward movement in the middle of the bed and downward movement near the side walls. The distribution of bed density in PFB showed more stable condition from the spatial and temporal aspects. Finally, based on the orthogonal experiments, a correlation for estimating the fluctuations in bed density was established to illustrate the optimum values for bed height and pulsation frequency for airflow, which had values of approximately 100 mm and 2.0 hz, respectively. [ABSTRACT FROM AUTHOR]

Dead-ended proton exchange membrane fuel cells (PEMFCs) using pure hydrogen and oxygen can improve fuel efficiency and cell performance, making them widely applicable in enclosed spaces. However, dead-ended PEMFCs are prone to flooding, which reduces cell performance and service life. To address this issue, an oxygen recirculation system utilizing oscillating flow generated by pressure differences is designed in this study. This system not only achieves close to 100% fuel utilization but also optimizes water management and enhances current density uniformity. The optimal oxygen cycling conditions were selected based on current density uniformity and cell performance enhancement. The results show that a larger pressure difference amplitude improves water removal from the cell; however, excessively large pressure differences can lead to unstable cell operation. The oscillating flow generated by pressure differences significantly improved current density uniformity, particularly at higher output load currents. Current density uniformity improved by 16.29% at a current of 75 A. The experiment demonstrates that the best current density uniformity is achieved when managing water using a pressure difference at 4-minute intervals, as longer or shorter oscillation intervals are unsuitable for dead-ended performance. [ABSTRACT FROM AUTHOR]

In view of the lack of research on the microscopic thermal conductivity mechanism in the formation of methane hydrate in porous media, a molecular dynamics method was proposed to simulate the porous media gap model composed of SiO2. According to the microstructure of the simulated system, EMD method and NEMD method were proposed to study the thermal conductivity change process of the homogeneous solution in the SiO2 gap, and the molecular conformation diagram and density distribution cloud diagram of SiO2 intact gap and defect gap were analyzed. The influence law of SiO2 on the thermal conductivity in the initial stage of methane hydrate formation was obtained and the microscopic mechanism was analyzed. The results show that the mean thermal conductivity of the homogeneous solution with SiO2 gap obtained by EMD method is 0.53 W/（m·K）, and that of the homogeneous solution is 0.74 W/（m·K）. The thermal conductivity of homogeneous solution, intact SiO2 gap and defective SiO2 gap obtained by NEMD method is 0.986, 0.581 and 0.439 W/（m·K）, respectively. The EMD method and NEMD method are used to verify that the existence of SiO2 gaps is conducive to the formation and storage of methane hydrate, and the simulated thermal conductivity values are close to the measured values. SiO2 containing gaps can significantly reduce the thermal conductivity of the simulated system, which is conducive to the formation and storage of methane hydrate.

The density distribution in an urban matrix is one of the significant issues which affects other urban living factors such as building lighting, energy consumption and residents' interactions. The research toward achieving the optimum density distribution has received attention for the last decade. However, developing a generative approach that provides more freedom for the formation of the plans and incorporates adaptability in different land blocks is still missing. To address such a gap, this study proposes an adaptable approach developing the formation of residential blocks. This formation is according to the pre-defined size and shape of the land, and sought performance objectives. Hence, a suite of applications including Grasshopper, Python and Ladybug were applied in a residential block of Tehran as a case study. The purpose is to develop a new density distribution increasing view quality, visual privacy, and solar gain. For the optimization process, a genetic algorithm was applied utilizing the topology optimization technique. The results of the optimization process highlight the significance of this research since the developed alternatives are more efficient in terms of improving the view quality, visual privacy and increasing the solar gain. This achievement expands the potential of this research to be applied in different case studies and with different design and development objectives in order to develop better shape plans of building blocks. [ABSTRACT FROM AUTHOR]

In this paper, we numerically investigate the dynamic response and explosion resistance of gradient aluminum foam sandwich tubes subjected to external blast loads. Based on 3D-Voronoi technology, we construct density-graded aluminum foam cores to systematically explore the influence of core density distribution, density gradient, and average relative density on the protective performance of these structures. Our primary objective is to identify optimal design parameters that maximize explosion mitigation capabilities while balancing energy absorption and specific energy absorption capacities. The research results show that a positive gradient core configuration exhibits superior anti-explosion performance, significantly outperforming its uniform and negatively graded counterparts, particularly when the gradient value is substantial. For the positive gradient cores, an increase in the gradient value leads to a corresponding enhancement in explosion resistance. Conversely, in negatively graded cores, a higher gradient value diminishes the anti-explosion performance. Furthermore, while augmenting the relative density of the core layer does improve the overall explosion resistance of the sandwich tube, it comes at the cost of reduced energy absorption and specific energy absorption capabilities, highlighting the need for a delicate balance among these competing factors. [ABSTRACT FROM AUTHOR]

Segregation in concrete significantly affects its durability and structural integrity by introducing local variance in both the strength distribution and the modulus of elasticity within a structural element. Additionally, segregation can lead to durability complications, such as shrinkage induced cracking. Recent observations have identified such segregation issues in already existing structures, underscoring the importance of assessing segregation. In this study, we evaluate the extent of segregation in normally vibrated concrete specimens, which were subjected to different vibration durations and vibrated using either table or poker vibrators. The research introduces three segregation indices to assess this phenomenon. One index relies on the standard deviation of densities across multiple slices of each specimen, while the other two utilize Digital Image Processing (DIP) to analyse the distribution of aggregates in horizontal and vertical slices, respectively. High correlations were found between the density-based index and vibration time for both poker-vibrated and table-vibrated specimens. The DIP-based indices showed strong correlations with the density-based approach, offering quicker alternatives for assessing segregation. The study further proposes classification levels for segregation based on these methods and reveals the negative impact of increased air entrainment on segregation. These findings provide insights for optimizing concrete compaction processes and understanding segregation.

Mesocarnivores are major components of carnivore assemblages, and they play important roles in structuring communities and regulating community dynamics. In Southwest China, many apex predators have been extirpated, and this has potentially resulted in the ecological release of mesocarnivores. Estimating the sizes of mesocarnivore populations is challenging. We used DNA derived from hairs and spatial capture–mark–recapture techniques to estimate the population size of masked palm civets (Paguma larvata) in Laohegou Nature Reserve in the Minshan Mountains of Sichuan Province, China. In the fall of 2014 and the spring of 2015, we collected 144 and 230 hair samples, respectively, at 30 baited stations. We used 16S rRNA fragments, microsatellite genotyping, and sexing to determine that 191 samples were derived from 44 masked palm civet individuals (24 males and 20 females). Using spatially explicit capture–recapture analysis, we estimated that there were 82 ± 13 masked palm civets in the study area, with a density of 1.7 individuals/km2. This is the first study to estimate the population size of masked palm civets in the wild. Our data provide important new information on the density of masked palm civets. [ABSTRACT FROM AUTHOR]

When dealing with processes involving the compaction of bulk materials, very often the quality of the product is determined based on density measurements. Methods used in the industry do not produce compacted materials with high degrees of homogeneity. As a result, the quality of the resulting product, interpreted as its density, varies over the cross-section of the product. In this article, the authors present the results of a numerical study involving the analysis of the density distribution of compacted dry ice during the reciprocating process. The Drucker–Prager/cap model was used in this study, which allowed the change in mechanical properties of the compacted material to be taken into account during the simulation of the process. The diameter, height and density of the cylindrical specimens used in the numerical tests were taken as the variable parameters. Thus, as a result of the testing, the authors could formulate conclusions relating to their impact on the homogeneity of the material. [ABSTRACT FROM AUTHOR]

A declined table test is proposed to determine the fresh properties of mortar and concrete. Different from the conventional slump test that is conducted on the flat table, a flow angle of fresh mortar or concrete will appear through the slump test on the declined table. This study investigates the relationships between the fresh properties tested by the conventional slump test and the flow angles on the declined table, with reference to the visual stability index specified in the ASTM C1611 and density distribution method based on the conventional slump test, the feasibility of the declined table method to evaluate the dynamic segregation of fresh concrete is verified. The results indicate that the mortar and concrete with higher fluidity have larger flow angles on the declined table, but the mortar with an unstable state shows an increased trend in the flow angle. The concrete generally has a lower flow angle than the affinal mortar. The ratio of the flow angle of mortar (Am) to the flow angle of concrete (Ac) is feasible to evaluate the dynamic segregation extent of fresh concrete, and a higher Am/Ac value means a severer dynamic segregation tendency. Using a reasonable classification of Am/Ac, the declined table test is feasible to determine whether the fresh concrete is stable or not. [ABSTRACT FROM AUTHOR]

In this paper, the penetration mechanism of reactive jet with non-uniform density distribution is studied. The simulations show that the density deficit occurs in the whole reactive jet, and the density increases from the jet tip to tail. The density of jet tip is approximately 1.5 g/cm3, which is lower than that of the reactive liner materials. The X-ray experiments show similar results with the simulations. The density decreasing effect of jet tip has a significant influence on the penetration behavior when the reactive jet impacts steel plate. According to the simulation results, this paper assumes that the density gradient in the jet section has linear distribution. Then, the deflagration pressure generated by each jet element at the bottom of crater is introduced into the Bernoulli equation. Based on the virtual origin model and Szendrei-Held equation, the analytical models for penetration depth and radial cratering of reactive jet with the density reduction are obtained. Moreover, to further prove the validity of analytical models, the penetration experiments of the reactive liner shaped charge against steel plate under different standoffs are carried out. There is a convergence between the analytical crater profiles and experimental results when reactive jets penetrate steel plates under different standoffs, especially at standoff of 1.5 and 2.0 charge diameters.

The nonnegative blind source separation (NBSS) algorithm based on minimum volume simplex (MVS) criterion is excessively dependent on the shape of the mixture scatterplot, resulting in the situation in which the MVS-based algorithm may have no solution. In this paper, we propose a new noiseless NBSS model and introduce edge features into high-order determined NBSS. The edge feature-based NBSS model can compensate for the shortcomings of the MVS-based algorithm. The twice projections (TP) algorithm is designed to replace the existing clustering and regression algorithms; moreover, TP prevents the aliasing phenomenon caused by direct projection and effectively reduces the time complexity of dimension reduction. We search for the coordinates of the density maximum points in 2-D space, and gradually merge them into high-dimensional coordinates, which greatly reduces the complexity of the algorithm. Furthermore, we only make boundedness and nonnegativity assumptions about the source, which makes the algorithm more widely applicable. [ABSTRACT FROM AUTHOR]

In studies of dynamic stability and power quality, it is necessary to know the values of the mechanical parameters determining the transient response of wind turbines. Their exact values are not as decisive as the power curve, but an inaccurate estimate can distort or even invalidate the simulation results. From a review of the literature, it has been found that, despite their importance, the values of inertia, stiffness and damping are hardly available for any turbine model. Another detected problem is the lack of confidence in the data origin. This article aims to solve the issue of the scarcity and unreliability of data on inertia, and gathers the information found on the remaining mechanical parameters. Available blade inertia values in kg · m 2 are presented. Special treatment has been given to those providing the mass distribution along the blade span, for which the provided values of inertia have been compared with those obtained numerically, showing good matching. With this, different reliable relations are obtained that allow for the calculation of the turbine rotor inertia, based on the mass and length of the blade. When the center of gravity is also available, a very correlated expression ( r 2 = 0.975 ) is provided to obtain the inertia. The references to the stiffness and damping constant of the drive train, which are even more rare, will also be presented. In addition, the study includes a revision of gearboxes, generators and blade weight, according to their IEC-class and material. [ABSTRACT FROM AUTHOR]

Introduction: Mast cells are heterogenous group of immune cells involved in multiple biological events they play vital role in various inflammatory and immunological reactions, linking humoral and cell mediated phases of processes. Aim and Objective: In this study we have tried to compare the density and distribution of mast cells in various endometrial lesions. Material and Methods: A prospective study with 101 cases of post hysterectomy were studied. Hysterectomy specimens were cut open from anterior wall, incorporated endometrium and myometrium, fixed in 10% formalin after routine processing, embedded in paraffin, 5 micron thickness section taken and stained with Haematoxillin-Eosin, and toludine blue to visualize mast cells. Results: It showed a significant p value which was < 0.001. Conclusion: Mast cell profile may be an additional diagnostic/prognostic tool in different endometrial lesions.

In terms of the core nucleus plus valence nucleon, shell-model calculations using two model spaces and interactions, the relationship between a nucleus' proton skin, and the difference in proton radii of mirror pairs of nuclei with the same mass number are investigated. In this work, two pairs of mirror nuclei will be studied: 17Ne-17N and 23Al-23Ne. For 17Ne-17N nuclei, p-shell and mixing of psd orbits are adopted with Cohen-Kurath (ckii) and psdsu3 interactions. While for 23Al-23Ne, the sd-shell and sdpf shell are adopted with the universal shell model (USD) and sdpfwa interactions. Also, the ground state density distributions, elastic form factors, and root mean square radii of these pairs' nuclei are studied and compared with available experimental data. . In general, it was found that the rms radius of the valence proton(s) is larger than that of the valence neutron(s) in its mirror nucleus. The results show that these nuclei have the exotic structure of a halo or skin.

Achieving uniformly distributed reinforcement particles in a dense matrix is crucial for enhancing the mechanical properties of nanocomposites. This study focuses on fabricating Mg-SiC nanocomposites with a high-volume fraction of SiC particles (10 vol.%) using cold isostatic pressing (CIP). The objective is to obtain a fully dense material with a uniform dispersion of nanoparticles. The SiC particle size impact on the compressibility and density distribution of milled Mg-SiC nanocomposites is studied through the elastoplastic Modified Drucker-Prager Cap (MDPC) model and finite element method (FEM) simulations. The findings demonstrate significant variations in the size and dispersion of SiC particles within the Mg matrix. Specifically, the Mg-SiC nanocomposite with 10% submicron-scale SiC content (M10Sµ) exhibits superior compressibility, higher relative density, increased element volume (EVOL), and more consistent density distribution compared to the composite containing 10% nanoscale SiC (M10Sn) following CIP simulation. Under 700 MPa, M10Sµ shows improvements in both computational and experimental results for volume reduction percentage, 2.31% and 2.81%, respectively, and relative density, 4.14% and 3.73%, respectively, compared to M10Sn. The relative density and volume reduction outcomes are in qualitative alignment with experimental findings, emphasizing the significance of particle size in optimizing nanocomposite characteristics. [ABSTRACT FROM AUTHOR]

The permanent power loss and the deviation of the trajectory of satellites impacted by centimetre and sub-centimetre sized debris have highlighted the need of taking into account such small fragments in the evolutionary models of the debris population and in the assessment of the in-orbit collision risk. When scaling down to the centimetre-millimetre range, deterministic models for propagating the fragments' orbit suffer from the massive computational cost required. The continuum approach for modelling the debris clouds is a well-established alternative to the piece-by-piece propagation. A density function is formulated to describe the distribution of fragments over a suitable phase space. Accurate and efficient continuum formulations have been developed to propagate clouds of fragments under atmospheric drag and J 2 perturbations, but a general model able to work under any dynamical regime has still to be found. This paper proposes a continuum approach that combines the method of characteristics with the discretisation of the domain in Keplerian elements and area-to-mass ratio into bins. The problem of using a binning approach with such a multi-dimensional phase space is addressed bounding and partitioning the domain, through probabilistic models on the way the fragments distribute over the phase space, as consequence of a fragmentation event. The proposed approach is applied to the modelling and propagation of a space debris cloud under the full set of orbital perturbations, and compared against a Monte Carlo simulation in terms of objects' number and distribution. The method proves to be accurate on the medium scale, in both space and time, and guarantees statistical validity with a reduced computational effort, leveraging its probabilistic nature. [ABSTRACT FROM AUTHOR]

Artemisia frigida, as an important indicator species of grassland degradation, holds significant guidance significance for understanding grassland degradation status and conducting grassland restoration. Therefore, conducting rapid surveys and monitoring it is crucial. In this study, to address the issue of insufficient identification accuracy due to the large density and small size of Artemisia frigida in UAV images, we improved the YOLOv7 object detection algorithm to enhance the performance of the YOLOv7 model in Artemisia frigida detection. We applied the improved model to the detection of Artemisia frigida across the entire experimental area, achieving spatial mapping of Artemisia frigida distribution. The results indicate: In comparison across different models, the improved YOLOv7 + Biformer + wise-iou model exhibited the most notable enhancement in precision metrics compared to the original YOLOv7, showing a 6% increase. The mean average precision at intersection over union (IoU) threshold of 0.5 (mAP@.5) also increased by 3%. In terms of inference speed, it ranked second among the four models, only trailing behind YOLOv7 + biformer. The YOLOv7 + biformer + wise-iou model achieved an overall detection precision of 96% and a recall of 94% across 10 plots. The model demonstrated superior overall detection performance. The enhanced YOLOv7 exhibited superior performance in Artemisia frigida detection, meeting the need for rapid mapping of Artemisia frigida distribution based on UAV images. This improvement is expected to contribute to enhancing the efficiency of UAV-based surveys and monitoring of grassland degradation. These findings emphasize the effectiveness of the improved YOLOv7 + Biformer + wise-iou model in enhancing precision metrics, overall detection performance, and its applicability to efficiently map the distribution of Artemisia frigida in UAV imagery for grassland degradation surveys and monitoring.

The presented research is devoted to the construction and calculations of the density model along the regional CMRV-DSS profile RP-17 (Chop–Velykyy Bychkiv), running along the Transcarpathian depression. Based on the results of density modeling, the distribution of density in the Earth’s crust was obtained in accordance with its seismic structure and gravity field as well as the density structure of individual layers. A tectonic interpretation of the obtained results was provided. The Mukachevo and Solotvyno parts of Transcarpathian depression have their own structural features, autonomous geological development and are distinguished by Neogene geodynamics. The analysis of density properties showed that in the Neogene sedimentary layer of both depressions there is a change in the density of various rocks in the depth intervals of 200—950; 950—1450; 1450—2050 m. In the Solotvyno depression in the depth intervals of 200—950 and 1450—2050 m, the density is greater than in Mukachevo, due to the presence of sandstones, tuffs, mudstones, and siltstones. In the interval 950—1450 m of Solotvyno depresson, on the contrary, the density is lower than in Mukachevo one, due to the presence of salt and clay. The Earth’s crust of Mukachevo depression is more compacted, as it contains a «basalt» layer. The Solotvyno depression consists of two parts and its average density corresponds to a diorite composition. The north-western block is of higher density and more homogeneous. The south-eastern one is of lower density and composed of a large number blocks of different densities separated by faults. The boundary of the lower density zone (PK 105—110) runs along the south-eastern branch of the Stryi-Latorytsia shear zone. This zone appears fragmentary on the density section, being similar to a mantle fault, with a lateral differentiation of density values, as well as the largest concentration of earthquakes, especially in the upper part of the Earth’s crust. The low-density area is probably associated with the transition from the Solotvyno depression to the structures located to the south-east of it. Thus, the block with the lowest density (2,38 g/cm3) of the Mesozoic-Paleozoic folded basement can be attributed to the Fore-Alkapa suture zone, represented by the Pieniny Klippen Belt and the Monastyrets nappe, which turns in the meridional direction in the zone of junction with the Tisza-Dacia terrane. The block located below with a density of 2,64 g/cm3 can be connected with the Marmarosh massif, or with the Rakhiv nappe. It was established that the crust of the Alkapa terrain along the profile is represented by three large blocks with a smaller block structure inside each one. The two more density blocks with different crust structure correspond to the Mukachevo depression. The lowest density third block belongs to the north-eastern part of the Solotvyno depression, the eastern border of which coincides with the area of clustering of earthquake hypocenters. The south-eastern part of the Solotvyno depression probably represents a transition zone between the Alkapa and Tisza–Dacia terrains. Two lithospheric fault zones are distinguished. The first one separates Mukachevo and Solotvyno depressions. The second zone is located between the Khust and Tyachiv faults in the low-density zone along the entire section of the Earth’s crust. These two zones are assumed to be connected by the Vynogradiv fault. It is characterized by a large cluster of earthquakes and located in the transition from extension and subsidence to compression and uplift. Low velocity (density) zones of the Transcarpathian depression can be associated with lithospheric fault zones. There are the most active horizons of modern geological and geophysical transformations of the mineral environment of the Earth’s crust and can be a potential source of deep oil and gas.

Nuclear structure of 20,22Ne isotopes has been studied via the shell model with Skyrme-Hartree-Fock calculations. In particular, the transitions to the low-lying positive and negative parity excited states have been investigated within three shell model spaces; sd for positive parity states, spsdpf large-basis (no-core), and zbme model spaces for negative parity states. Excitation energies, reduced transition probabilities, and elastic and inelastic form factors were estimated and compared to the available experimental data. Skyrme interaction was used to generate a one-body potential in the Hartree-Fock calculations for each selected excited states, which is then used to calculate the single-particle matrix elements. Skyrme interaction was used to calculate the radial wave functions of the single-particle matrix elements, from which a one-body potential in Hartree-Fock theory with SLy4 parametrization can be generated. Furthermore, we have explored the interplays among neutron and proton density profiles in two dimensions, along with the deformations of 20,22Ne using Hartree-Fock plus BCS calculations.

Background: Magnesium is one of the most abundant elements in the body. Although the total serum magnesium content does not represent more than 1% of total body magnesium, serum magnesium determinations have been routinely used in clinical practice to assess body magnesium status. Thus, serum magnesium concentration ranges from 1.8 to 2.2 mg.dl−1 (0.75–0.95 mmol.l − 1 or 1.5–1.9 mEq.l − 1). Consequently, when serum magnesium levels fall below the range considered normal, the patient is diagnosed with hypomagnesemia. This deficiency has been associated with low-grade systemic inflammation, increased levels of proinflammatory molecules, mitochondrial dysfunction, increased reactive oxygen species production, and hypertriglyceridemia leading to an increase in the number of easily oxidizable lipoproteins in the circulation. Results: Several magnesium salts have been used to treat hypomagnesemia during pregnancy, with magnesium sulfate (MgSO4) being the most commonly used magnesium salt in current obstetric practice. However, the exact mechanism of action of MgSO4 remains largely an enigma, and its parenteral use poses a significant toxicological risk at high doses. In this review, we summarize the use of magnesium salts during pregnancy not only from a clinical point of view but also, with the use of computational simulations, discuss advances in the understanding of the molecular mechanisms of action of magnesium salts, with emphasis on MgSO4. These molecular simulations are required to unveil the pharmacological action of the magnesium salts during pregnancy. Conclusions: MgSO4 plays a role as an antioxidant agent at the plasma membrane level which can explain the mechanism of action of this salt in current obstetric practice.

Elastic scattering cross sections are a fundamental aspect of nuclear physics research, and studying the cross sections of various nuclei can provide important insights into the behavior of nuclei. In this study, the elastic scattering cross sections of 10C projectile by 27Al, 58Ni, and 208Pb target nuclei are analyzed. The aim of this study is to investigate the cluster structure of 10C and the sensitivity of the elastic scattering cross sections to different potentials. To achieve this objective, the double folding optical model and a simple cluster approach are used to analyze the cross sections. The real part of the optical potential is obtained by folding two different effective interactions, Michigan-3-Yukawa (M3Y) and JeukenneLejeune-Mahaux (JLM), with four different cluster density distributions of the 10C nucleus: 6Be + \alpha, 9B + p, 8Be + p + p, and \alpha + \alpha + p + p. The imaginary part is taken to be a Woods-Saxon phenomenological form. The sensitivity of the elastic scattering cross sections to different potentials is assessed by comparing the results obtained using different potentials. The cluster structure of 10C is validated by comparing the theoretical results with experimental data. The results show that the cross sections are sensitive to the choice of potential used and that the cluster structure of 10C is validated. The theoretical results show reasonable agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Using the matrix diagonalization method within the effective mass approximation and the rectangular potential profile, we investigate optical absorption coefficients (OAC) in the core-shell quantum antidot (QAD) Al0.3Ga0.7 As/GaAs/Al0.3Ga0.7 As in the presence of applied co-directed electrical and magnetic fields. The electric field effect on the electron wave functions, energy spectrum, oscillator strength of the intersubband electronic transitions is calculated for different size of QAD core and different value of the magnetic field induction. The total, linear and nonlinear optical absorption coefficients in QAD are obtained by considering 1 s-1p and 1p-1d electron quantum transitions as functions of the incident photon energy. [ABSTRACT FROM AUTHOR]

In studies of dynamic stability and power quality, it is necessary to know the values of the mechanical parameters determining the transient response of wind turbines. Their exact values are not as decisive as the power curve, but an inaccurate estimate can distort or even invalidate the simulation results. From a review of the literature, it has been found that, despite their importance, the values of inertia, stiffness and damping are hardly available for any turbine model. Another detected problem is the lack of confidence in the data origin. This article aims to solve the issue of the scarcity and unreliability of data on inertia, and gathers the information found on the remaining mechanical parameters. Available blade inertia values in kg · m2 are presented. Special treatment has been given to those providing the mass distribution along the blade span, for which the provided values of inertia have been compared with those obtained numerically, showing good matching. With this, different reliable relations are obtained that allow for the calculation of the turbine rotor inertia, based on the mass and length of the blade. When the center of gravity is also available, a very correlated expression (r2=0.975) is provided to obtain the inertia. The references to the stiffness and damping constant of the drive train, which are even more rare, will also be presented. In addition, the study includes a revision of gearboxes, generators and blade weight, according to their IEC-class and material.

Introduction: Mini-tablets are considered a promising solid dosage form in the pharmaceutical industry due to advantages such as dosing accuracy, efficiency as a drug delivery system, and alleged improvement in mechanical properties. Nevertheless, only a few experimental studies are available in the literature regarding this topic and technical aspects, such as punch's shape and size effect on the stress and density distribution in the compact mini-tablets, are still not fully investigated. Objectives: In this paper, the influence of powder properties and process parameters, such as punch shape and size, on the evolution of mechanical properties during the tableting process and the potential occurrence of tablet defects are investigated using the mechanistic modeling approach, Finite Element Method (FEM). Methods: The numerical simulation cases consist of four different die sizes, mini-tablets of 2 mm, and 3 mm, and conventionally sized tablets of 8 mm and 11.28 mm. Each tablet size is simulated using four distinctive excipients, Avicel® PH-102, Kollidon® VA64, Pearlitol® 100SD, and Supertab® 11SD, and two different punch geometries, a flat-face punch, and a bevel edge punch. Results: The model predictions in terms of stress and density distribution at different stages of the compaction process indicate similar behavior in terms of density and stress distribution profiles between the conventionally sized tablets and mini-tablets for a particular excipient. Conclusions: Based on tablet size, small localized differences are noted (e.g., low-density regions, high shear bands, and heterogeneous density profiles), suggesting a possible risk of tableting defects for conventionally sized tablets compared to mini-tablets. Furthermore, it is observed that bevel-edged tablets could facilitate the formation of cracks, leading to possible capping failure. [ABSTRACT FROM AUTHOR]

This work aims at improving the thermal shock resistance of Si3N4-SiC refractories. Si3N4-SiC specimens were prepared through two means:vacuum vibration casting and machine pressing, using industrial SiC particles and Si powder as raw materials and nitridation-firing at 1 400 °C for 8 h. The properties and density distribution of the specimens were characterized, and a water quenching method combined with a residual fracture toughness test program was designed to evaluate the thermal shock resistance of the Si3N4-SiC refractories. The comparison results indicate that the vacuum vibration cast specimens have better general properties and higher fracture toughness retention ratio, more uniform density distribution and less crack sources than the traditional pressed specimens, hence the vacuum vibration cast specimens have better thermal shock resistance than the traditional pressed ones. [ABSTRACT FROM AUTHOR]

Aluminum alloy green compacts obtained by single-action compaction in lubricated and unlubricated dies were investigated by X-ray tomography. For the purpose of obtaining the relationship between the density of green compact and the gray value of reconstructed images, linear fitting was performed. The results show that these data have excellent linear relationship. Then, a new method for analysis of compaction process was presented in this paper. Detailed quantitative analysis of the density and compressive pressure distribution in green compacts was performed. The compressive pressure transmitted ratio and friction index were also discussed. It is found that the lubricated die wall has better effects on the density homogeneity at lower applied compressive pressure. During compaction process, the densification of powder particles in the die mainly occurs in the lower part of the green compact and the factor which mainly influences the friction between die wall and green compact is the applied compressive pressure. [ABSTRACT FROM AUTHOR]

Biomass and species composition of demersal fish in the bottom biotopes of Peter the Great Bay (Japan Sea) are considered on the data of 2428 trawl catches in 36 surveys conducted by Pacific Res. Inst. of Fisheries and Oceanography (TINRO) in 1978–2009. The most common 20 species are ranked, as the basis of ichthyocenoses, by areas of the bay. The long-term mean total biomass of fish in the bay is estimated as 75,500 t. Arabesque greenling Pleurogrammus azonus, japanese flounder Pseudopleuronectes yokohamae and saffron cod Eleginus gracilis are distinguished by the highest mean biomass. Mean density of fish distribution varied from 6.2 to 19.4 t/km2. It was the highest in the middle Ussuri Bay (13.95 t/km2; mean fish biomass in the area 18,230 t) and in the estuarine areas. Besides, the data on long-term mean biomass of benthos collected in the same trawl surveys and zooplankton sampled in 117 plankton surveys in 1988–2013 are presented.

Abstract The sapwood and heartwood of plantation sugi wood (Cryptomeria japonica), and plantation hinoki (Chamaecyparis obtusa) wood were flat-sawn into timbers, then kiln-dried to a MC level below 12%. These timbers were further processed into specific sizes and wetted on the surfaces, preheated at 150 °C and radially compressed into sandwich compressed timbers. Density distribution, compressed layer(s) position and thickness, surface hardness were investigated. It was demonstrated that sugi and hinoki timbers were both applicable for sandwich compression. By controlling the preheating time, sugi heartwood timber, sugi sapwood timber and hinoki timber can be all sandwich compressed, which resulted in surfaces compressed timbers, interior compressed timbers and center compressed timbers. When sugi timbers were sandwich compressed, density only tremendously increased in the earlywood. The increased density of the compressed sugi earlywood was independent of compressed layer(s) position, compressing distance or annual growth width, while for hinoki timbers compression, density increased both in earlywood and latewood. Surface hardness of the uncompressed sugi sapwood was almost twice of that of the uncompressed sugi heartwood. Surface compression sharply increased the surface hardness of sugi heartwood and sugi sapwood. Interior compression and center compression also contributed to increased surface hardness for the compressed timbers, but to smaller extents. Surface hardness change due to the surface compression was consistent with the surface average density change of timbers. Compression layer(s) position exerted statistically significant effects on the surface hardness, while surface hardness of the compressed wood was almost unrelated to the original density of the used wood or average density of the sandwich compressed wood. However, bigger compressing distance led to bigger surface hardness for the surface compressed wood.

Achieving uniformly distributed reinforcement particles in a dense matrix is crucial for enhancing the mechanical properties of nanocomposites. This study focuses on fabricating Mg-SiC nanocomposites with a high-volume fraction of SiC particles (10 vol.%) using cold isostatic pressing (CIP). The objective is to obtain a fully dense material with a uniform dispersion of nanoparticles. The SiC particle size impact on the compressibility and density distribution of milled Mg-SiC nanocomposites is studied through the elastoplastic Modified Drucker-Prager Cap (MDPC) model and finite element method (FEM) simulations. The findings demonstrate significant variations in the size and dispersion of SiC particles within the Mg matrix. Specifically, the Mg-SiC nanocomposite with 10% submicron-scale SiC content (M10Sµ) exhibits superior compressibility, higher relative density, increased element volume (EVOL), and more consistent density distribution compared to the composite containing 10% nanoscale SiC (M10Sn) following CIP simulation. Under 700 MPa, M10Sµ shows improvements in both computational and experimental results for volume reduction percentage, 2.31% and 2.81%, respectively, and relative density, 4.14% and 3.73%, respectively, compared to M10Sn. The relative density and volume reduction outcomes are in qualitative alignment with experimental findings, emphasizing the significance of particle size in optimizing nanocomposite characteristics.

Drying of textiles in industrial facilities represents an energy-intensive process where a large number of measures for energy and production cost savings can be introduced. Typical measures include the introduction of energy management, waste-heat recovery, process optimization and so on. Drying is a complex process with coupled heat and mass transfer between the heated air and humid textile, where parameters such as the air flow rate, air velocity and its flow regime and textile velocity and water content represent significant influential factors. The distribution of air temperature and density inside the drying section of an industrial stenter frame is analyzed in detail using three-dimensional numerical simulation, where the textile is modeled as a porous medium to analyze moisture diffusion within the textile. Heated air is introduced into a chamber by inlet nozzles and removed by exit nozzles, the distribution of which is based on actual machine configuration. A humid textile is introduced into a section, where temperature and density distribution within the textile are calculated for selected time periods. During the simulation in the Fluent program, models of specific component transport, multiphase air flow, turbulent flow, porosity and evaporation were used. The results represent a valuable data set that provides an in-depth insight into the drying process in the industrial stenter machine. [ABSTRACT FROM AUTHOR]

Lunar craters and rilles are significant topographic features on the lunar surface that will play an essential role in future research on space energy resources and geological evolution. However, previous studies have shown low efficiency in detecting lunar impact craters and poor accuracy in detecting lunar rilles. There is no complete automated identification method for lunar features to explore space energy resources further. In this paper, we propose a new specific deep-learning method called high-resolution global–local networks (HR-GLNet) to explore craters and rilles and to discover space energy simultaneously. Based on the GLNet network, the ResNet structure in the global branch is replaced by HRNet, and the residual network and FPN are the local branches. Principal loss function and auxiliary loss function are used to aggregate global and local branches. In experiments, the model, combined with transfer learning methods, can accurately detect lunar craters, Mars craters, and lunar rilles. Compared with other networks, such as UNet, ERU-Net, HRNet, and GLNet, GL-HRNet has a higher accuracy (88.7 ± 8.9) and recall rate (80.1 ± 2.7) in lunar impact crater detection. In addition, the mean absolute error (MAE) of the GL-HRNet on global and local branches is 0.0612 and 0.0429, which are better than the GLNet in terms of segmentation accuracy and MAE. Finally, by analyzing the density distribution of lunar impact craters with a diameter of less than 5 km, it was found that: (i) small impact craters in a local area of the lunar north pole and highland (5°–85°E, 25°–50°S) show apparent high density, and (ii) the density of impact craters in the Orientale Basin is not significantly different from that in the surrounding areas, which is the direction for future geological research. [ABSTRACT FROM AUTHOR]

Finite element analysis (FEA) is a computational method providing numerical solutions and mathematical modeling of complex physical phenomena that evolve during compression tableting of pharmaceutical powders. Since the early 2000s, FEA has been utilized together with various constitutive material models in a quest for a deeper understanding and unraveling of the complex mechanisms that govern powder compression. The objective of the present review paper is to highlight the potential and feasibility of FEA for implementation in pharmaceutical tableting in order to elucidate important aspects of the process, namely: stress and density distributions, temperature evolution, effect of punch shape on tablet formation, effect of friction, and failure of the tablet under stress. The constitutive models and theoretical background governing the above aspects of tablet compression and tablet fracture under diametral loading are also presented. In the last sections, applications of FEA in pharmaceutical tableting are demonstrated by many examples that prove its utilization and point out further potential applications. [ABSTRACT FROM AUTHOR]

MXenes, as two-dimensional (2D) transition metal carbides, carbonitrides, and nitrides, have very excellent electrical properties and surface activity and are increasingly used in supercapacitors, batteries, electromagnetic interference shielding, and composite materials. Still, the poor stability of MXene when exposed to aqueous oxygen and the poor ability to interact with the polymer matrix have become important factors limiting its' practical applications. To enhance stability, highly conductive and stretchable Ti 3 C 2 MXene/TPU sensing elements were prepared by a simple spraying process using thermoplastic polyurethane (TPU) as a substrate, and the sensing elements were encapsulated by polydimethylsiloxane (PDMS) to obtain MXene-TPU/PDMS constructed flexible strain sensors with excellent performance. This strain sensor features low detection limits (less than 0.005%, 0.5 μm), a wide sensing range (0–90%), a short response time (120.1 ms), and excellent durability (>3000 cycles). This strain sensor can be applied to a range of applications such as health detection, motion signals, detection of robot movements, and wearable electronic devices. [ABSTRACT FROM AUTHOR]

To investigate the adsorption mechanism of CO2 and CH4 with oxygen-containing functional groups in coal, the structural models of coal with different functional groups of carboxyl, hydroxyl, carbonyl, and ether bonds were constructed using Materials Studio software, and the adsorption isotherms, heat of adsorption, adsorption energy, energy distribution, and adsorption configurations of CO2 and CH4 adsorbed by different functional group structures were analyzed using the giant regular GCMC method. The results showed that the presence of carboxyl, hydroxyl, and carbonyl functional groups will promote the adsorption of CO2 by coal, and the intermolecular interaction energies of the model with the addition of carboxyl, hydroxyl, and carbonyl groups, and CO2 increased by 70.37%, 33.67%, and 14.26%, respectively. The order of the adsorption strength of the five structures is: AC-COOH > AC-OH > AC-O > AC > AC-OCH3, which indicates that the influence of oxygen-containing functional groups on the adsorption performance of CO2 by coal mainly depends on polarity. The presence of carboxyl, hydroxyl, and carbonyl functional groups weakens the adsorption of CH4 on coal, and the interaction energy between the model and gas molecules with the addition of carboxyl, hydroxyl, carbonyl, and ether bonds reduced by 41.83%, 36.14%, 26.22%, and 80.21%, respectively. The order of the adsorption strength of the five structures is: AC > AC-O > AC-OH > AC-COOH > AC-OCH3, which indicates that the effect of oxygen-containing functional groups on the adsorption of CH4 on coal mainly depends on hydrophobicity; the introduction of ether-bonded functional groups does not favor the adsorption of CO2 and CH4 molecules on coal. It indicates that the ether bond has a certain repulsive effect on CO2 and CH4 molecules. In different functionalized coal structures with the same carbon atom skeleton, there are different adsorption capacities for CH4 as well as CO2, but in the same functionalized structure, the adsorption magnitude relationship is CO2 > CH4, indicating that the coal body structure interacts with CO2 more than CH4. [ABSTRACT FROM AUTHOR]

The effects of yield stress of poplar (Poplar × euramericana cv. 'Neva') on temperature (60–210°C), moisture content (oven dry-30%) and grain response mechanism and as well as its role in the formation of sandwich compressed wood were studied in this paper. The results showed that the yield stress of wood was significantly affected by moisture content(MC), temperature and their interaction. Compared with temperature, the relative change rate of yield stress was nearly 10 times higher for each 1% increase in MC than for each 1°C increase in temperature. The experimental data revealed that the relative change rate of yield stress depended on the softening effect of wood by moisture and temperature. The asymmetry of yield stress in different grain direction also depended on wood hydrothermal softening effect. Raising the temperature or increasing the MC could make wood radial vs tangential asymmetry decrease and radial vs radial tangential asymmetry disappear. In the process of hydrothermal compression, the yield stress gradient caused by the hydrothermal softening inside the wood was the main reason for the formation of sandwich compressed wood, and provided a scientific basis for the controllability of the position and thickness of the compressed layer(s). [ABSTRACT FROM AUTHOR]

The present paper investigated the separation performance of tri-cone water medium cyclone and conducted simulation studies on flow field inside cyclone by ANSYS FLUENT, by comparison with that of single-cone cyclone. The separation mechanism was revealed by analysis of internal pressure distribution, speed distribution, turbulence intensity, and density distribution both in tri-cone and single-cone cyclones. Compared with single-cone cyclone, the density distribution of tri-cone cyclone was clearer: Along the center of the cyclone, the density of particles increased outwardly as the radius increased. Along the axial direction of the cyclone, the density of particles gradually increased from top to bottom for the three cones. By experimental study, the separation performance of tri-cone cyclone was better than that of single-cone cyclone, which was caused by much greater turbulence intensity in tri-cone cyclone in the central gas-phase region of the cone. The air drawn in from the underflow port carried the low-density particles in the inner liquid phase from the overflow port upon upward flow, which can improve the separation efficiency. [ABSTRACT FROM AUTHOR]

Terahertz time-domain spectroscopy (THz-TDS) is a novel technique which has been applied for pore structure analysis and porosity measurements. For this, mainly the anisotropic Bruggeman (AB-EMA) model is applied to correlate the effective refractive index (neff) of a tablet and the porosity as well as to evaluate the pore shape based on the depolarisation factor L. This paper investigates possible error sources of the AB-EMA for THz-TDS based tablet analysis. The effect of absorption and tablet anisotropy – changes of pore shape with porosity and density distribution – have been investigated. The results suggest that high tablet absorption has a negligible effect on the accuracy of the AB-EMA. In regards of tablet anisotropy the accuracy of the porosity determination is not impaired significantly. However, density distribution and variations in the pore shape with porosity resulted in an unreliable extraction of the tablet pore shape. As an extension of the AB-EMA a new concept was introduced to convert the model into bounds for L. This new approach was found useful to investigate tablet pore shape but also the applicability of the AB-EMA for an unknown set of data.

This paper gives a survey of several directions of research connected with Chebyshev--Hermite polynomials on finite-dimensional and infinite-dimensional spaces, in particular, of approaches using the Malliavin calculus and other methods of investigation of distributions of polynomials in Gaussian random variables. We give estimates for measures of sets of large and small values, estimates of distances in total variation norm between distributions of polynomials, and results on membership of such distributions in Nikolskii--Besov classes of fractional differentiability. New results are obtained on weak convergence of measures given by polynomial densities with respect to Gaussian measures. [ABSTRACT FROM AUTHOR]

A simulation model for studying the structure of an object by the method of layer-by-layer digital Compton radiography (tomography) is proposed. The developed model takes into account the geometric testing scheme, the parameters of the source and the gamma radiation recording unit equipped with a special collimator system. The simulation model of the method is implemented as a program in the MathCad system. The capabilities of the simulation model and the corresponding program are demonstrated for an aluminum barrier with spherical local inclusions. [ABSTRACT FROM AUTHOR]

Using a combination of molecular dynamics simulations and first‐principles calculations, the interaction of n‐alkanes with {101¯4} calcite/dolomite is investigated. It is observed that the n‐alkane molecules align preferentially parallel to the interface, despite interaction by weak physisorption, and give rise to distinct adsorption layers. The ordering turns out to be more pronounced on calcite than dolomite due to a smaller average velocity of the n‐alkane molecules. The observations are explained in terms of adsorption energies and charge transfers. The results show that functionalization is no prerequisite of structural ordering and a distinct mass density profile perpendicular to the interface. [ABSTRACT FROM AUTHOR]

The widespread availability of GPS-enabled devices and advances in positioning technologies have significantly facilitated collecting user location data, making it an invaluable asset across various industries. As a result, there is an increasing demand for the collection and sharing of these data. Given the sensitive nature of user location information, considerable efforts have been made to ensure privacy, with differential privacy (DP)-based schemes emerging as the most preferred approach. However, these methods typically represent user locations on uniformly partitioned grids, which often do not accurately reflect the true distribution of users within a space. Therefore, in this paper, we introduce a novel method that adaptively adjusts the grid in real-time during data collection, thereby representing users on these dynamically partitioned grids to enhance the utility of the collected data. Specifically, our method directly captures user distribution during the data collection process, eliminating the need to rely on pre-existing user distribution data. Experimental results with real datasets show that the proposed scheme significantly enhances the utility of the collected location data compared to the existing method. [ABSTRACT FROM AUTHOR]

This study investigates the absorption mechanisms of carbon dioxide (CO 2), hydrogen sulfide (H 2 S), and methane (CH 4) molecules in two imidazolium-based ionic liquids, namely 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]) and 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][DCA]). We employed molecular dynamics (MD) simulations applying umbrella sampling technique to calculate free energy profiles (FEPs) for gas molecules in the ILs. The results reveal CO 2 's pronounced affinity for the interface over the bulk in both ionic liquids (IL), whereas H 2 S exhibits facile penetration into both regions. CH 4 shows limited penetration into the IL bulk, remaining predominantly near the interface. We further explore the influence of ILs' anionic structures on gas accumulation sites by performing normal MD simulations. For instance, density profiles also confirm CO 2 's higher density in [EMIM][DCA] compared to [EMIM][SCN], reflecting the influence of anionic composition on CO 2 solubility. These insights offer valuable knowledge for designing efficient ILs for gas capture and separation applications. [ABSTRACT FROM AUTHOR]

The topographic potential bias at geoid level is the error of the analytically continued geopotential from or above the Earth’s surface to the geoid. We show that the topographic potential can be expressed as the sum of two Bouguer shell components, where the density distribution of one is spherical symmetric and the other is harmonic at any point along the normal to a sphere through the computation point. As a harmonic potential does not affect the bias, the resulting topographic bias is that of the first component, i.e. the spherical symmetric Bouguer shell. This implies that the so-called terrain potential is not likely to contribute significantly to the bias. We present three examples of the geoid bias for different topographic density distributions.