Spatial Distribution Of Material Research Articles

In-situ mapping of iron and titanium with the visible and near-infrared image spectrometer (VNIS) along the Yutu-2 rover traverse on the farside of the moon

In January 2019, China's Chang'E-4 probe successfully landed in the Von Kármán crater of the Moon's farside's South Pole-Aitken basin. Till August 2021, the Yutu-2 rover had worked for >32 lunar days. The Visible and Near-infrared Image Spectrometer (VNIS) is one of scientific payloads on board the rover that can collect in-situ spectral data. This provides a unique perspective for investigating the composition of the lunar surface materials. In this work, a local-scale FeO and TiO2 abundance mapping approach based on the in-situ VNIS data was proposed to utilize the fine spectral-spatial hyperspectral information. Improved FeO and TiO2 abundance inversion models were performed on each unshaded pixel to generate abundance maps. Experimental results obtained on 115 VNIS observation data along the Yutu-2's routing path confirm the effectiveness of the proposed approach, especially in the complex observation scenarios. Comparing with the in-orbit data products and the in-situ abundance results obtained by the reference methods, the effectiveness of the proposed in-situ FeO and TiO2 abundance mapping approach is validated. Furthermore, the proposed approach allows a detailed analysis of chemical properties and spatial distribution of lunar surface materials, and helps to discover abnormal targets according to the serial spectral observations along the rover's routing path, which reveals the great potential in more precise lunar surface material identification and analysis applications.

Methodological approach to determining promising “quarry cavities – backfill material” systems on the territory of Ukraine

The research is aimed at identifying promising “quarry cavities – backfill material” systems on the territory of Ukraine. Currently, the existing reclamation methods for quarry cavities do not provide for the earth’s surface level complete restoration. A number of industrial wastes, the accumulation of which is increasing rapidly, are potential backfill materials. An insufficiently studied and promising method for restoring the earth’s surface level is the formation of a backfill mass in quarry cavities, which can provide geomechanical stability. Nevertheless, in order to develop directions for backfilling, it is necessary to have information on the spatial distribution of quarry cavities and potential backfill materials on the territory of Ukraine, which is also insufficiently studied today. The paper forms and reveals a theoretical idea about the “quarry cavities – backfill material” systems. A number of important conditions for the harmonious existence and effective implementation of the specified promising systems are characterized. The methodology for creating the basis of an information-analytical map is presented, and the principles for determining and characterizing its main constituent elements are given. A new information-analytical map of the spatial location of potential backfill materials and formed quarry cavities on the territory of Ukraine has been created, on the basis of which possible “quarry cavities – backfill material” systems have been identified. It has been determined that today on the territory of Ukraine, for the earth’s surface level complete restoration, it is expedient to consider the formation of a backfill mass in quarry cavities in 12 districts, where there are promising “quarry cavities – backfill material” systems. The concept of a complete restoration development of the earth’s surface disturbed by mining operations in certain potential systems is possible under conditions of synergistic interaction between public authorities and private business. The practical result obtained is an important basis for creating an effective mechanism and effective measures for a complete restoration of the earth’s surface state, which will contribute to strengthening the international image of Ukraine as a responsible and environmentally conscious country.

(Invited) Optimizing the Binder Distribution in Battery Electrodes with Manufacturing Process Simulations and Machine Learning

The performance of lithium-ion battery cells strongly depends on the microstructure of the electrodes, which is determined by the spatial distribution of the active material, carbon additive, binder, and pores within the electrode volume. The manufacturing process determines this spatial distribution, which, in turn, determines the interfaces between these materials and the pores, thereby impacting the practical properties of the electrodes, such as their electrical conductivity, energy density, and wettability. The binder plays a crucial role in this process, as its spatial distribution controls the degree of percolation between the particles and the adhesion of the electrode with the current collector.Since 2017, we have been developing the ARTISTIC computational platform,1 which constitutes a digital twin of the battery electrode and cell manufacturing process. Supported by a combination of physics-based models and machine learning, this platform has been demonstrated by us for lithium-ion, sodium-ion, and solid-state batteries with electrodes produced by wet processing.2 The platform simulates each step of the manufacturing process, including mixing, coating/drying, calendering, electrolyte infiltration, and resulting cell performance. It allows for predicting 3D-resolved electrode and cell sandwich microstructures with their associated electrochemical performance as a function of the manufacturing parameters.In this talk, I will discuss how the ARTISTIC computational platform can optimize the spatial distribution of active material, carbon additive, and binder within the electrode volume. Using Bayesian Optimization, the platform predicts the manufacturing parameters required to obtain optimal electrodes in terms of several properties, such as electric conductivity, tortuosity factor, electroactive surface area, and energy density. I will particularly discuss the platform's capabilities to capture the adhesion of the electrode with the current collector through the binder. Additionally, I will present an extension of this digital twin for the 3D-resolved simulation of the dry processing of active material, carbon additive, and binder based on extrusion and compare the results (in the form of 3D-resolved electrode microstructures) with experimental data. Results from the wet and dry processing simulations will be discussed for electrodes made with different active material chemistries, such as NMC and LFP, and the crucial role of the binder in the heterogeneity of lithiation/delithiation of the electrodes upon their electrochemical cycling will be explored.Finally, building on our previously reported virtual reality digital tools for battery manufacturing,3 I will present a novel virtual reality interface that allows for the interactive and immersive use of the ARTISTIC computational platform to track the influence of manufacturing parameters on the active material, carbon additive, and binder's spatial location, as well as the resulting electrode properties. I will conclude by discussing why this virtual interface is also a powerful tool to assist in the electrode manufacturing optimization.

Global sensitivity analysis of parameters based on sPCE: The case study of a concrete face rockfill dam in northwest China.

To effectively identify the key material parameters of different zones of concrete face rockfill dams and improve the efficiency of parameter optimization, a global sensitivity analysis method of parameters based on sparse polynomial chaotic expansion (sPCE) is proposed in this paper. The latin hypercube sampling method is used to select multiple groups of material parameters, and then finite element method is used to calculate the displacement of dam characteristic nodes in dam body. On this basis, the displacement is expanded by sPCE, and the polynomial basis function is reconstructed by orthogonal matching pursuit to improve the construction and analysis efficiency of the proxy model. According to the chaos coefficients, Sobol' indices are calculated to evaluate the influence of the material parameters and their interaction on different displacements of the dam. The results show that the sPCE model can accurately simulate dam displacement and its statistical characteristics with a relatively small sample size. The sensitivity of the same parameter has spatial variability, and under the influence of parameter levels and spatial distribution of different materials, the parameter sensitivity ranking of different zones has certain differences. The proposed method provides a new reference to sensitivity analysis and uncertainty analysis for practical engineering.

Modulating spatial charge distribution of lignin for eco-friendly and recyclable triboelectric nanogenerator

Tailoring the spatial charge distribution of triboelectric materials highly determines the distributed energy harvesting efficiency of triboelectric nanogenerators (TENGs). Herein, transition metal (iron) ions coordinated alkali lignin was successfully demonstrated as the high-performance tribopositive nanofiller in biodegradable carboxymethyl cellulose (CMC) to construct biodegradable TENGs. Arising from the expanded electron cloud on lignin skeleton and reinforced tribopolarity induced by the conjunction interaction between foreign iron ions and aromatic ring on lignin, the optimized TENG delivers an Voc of 110 V, Isc of 8.97 µA, Qsc of 15.3 nC and maximum output power density of 147.19 mW/m2 under contact frequency of 1 Hz owing to the improved electron transfer between the counter electrodes. Furthermore, such green biofilm presented excellent water soluble and recyclable features in accompanied with stable output signals when suffering from cutting-reforming process at least 5 times due to the presence of abundant dynamic reversible non-covalent bonds. The discovery of extraordinary tribopositive behavior of the lignin as nanofiller may pave the way of eco-friendly TENGs with boosting triboelectric output performances for self-powered sensing or mechanical energy harvesting.

Inverse Modeling of the Initial Stage of the 1991 Pinatubo Volcanic Cloud Accounting for Radiative Feedback of Volcanic Ash

AbstractThe way volcanic clouds evolve is very sensitive to the initial spatial 3D distributions of volcanic materials, which are often unknown. In this study, we conducted inverse modeling of the Mt. Pinatubo cloud using total ozone mapping spectrometer 2D mapping of Aerosol Index and SO2 loading during the first three post‐eruption days to estimate the time‐dependent emissions profiles and initial 3D spatial distributions of volcanic ash and SO2. We account for aerosol radiative feedback and dynamic lofting of volcanic ash in the inversion calculations for the first time. This resulted in a lower ash injection height (by 1.5 km for ash) than without ash radiative feedback. The Pinatubo eruption ejected ≈77% of fine ash at 12–23 km, ≈65% of SO2 at 18–25 km. In contrast with previous studies, which suggested that all volcanic materials were emitted above the tropopause, a significant fraction of SO2 (5.1 of 15.5 Mt) and fine ash (37.2 of 66.5 Mt) were ejected in the troposphere, where SO2 quickly oxidized into sulfate aerosol that is short‐lived in the troposphere. This explains the early presence of sulfate aerosols in the plume and why the models can reproduce the observed volcanic aerosols' optical depth (AOD), assuming lower‐than‐observed SO2 emission in the stratosphere. Despite the quicker than in observations build‐up of sulfate AOD, in a month after the eruption, the evolution of the Pinatubo AOD simulated using the obtained ash and SO2 initial distributions converges with the available stratospheric aerosol and gas experiment observations.

Biomimetic 4D Printing Catapult: From Biological Prototype to Practical Implementation

Abstract4D printing technologies are currently suffering from the inability to produce rapid motions, which limit their applications that require fast shape transformation such as rapid unlocking and deployment of aerospace equipment. Herein, inspired by the shooting mechanisms of Viola verecunda fruit for seed dispersal, the 4D‐printed biomimetic catapult is developed. Based on the structure change characteristics of gradient fan‐shaped cells of the fruit pods during seed ejection, the biomimetic smart catapult is processed via the programming of spatial distribution of heterogeneous materials with various storage modulus enabled by additive manufacturing. This catapult can achieve high‐speed ejection with the logically stimuli of external force, temperature, light, humidity, or electricity. The proposed biomimetic 4D printing strategy has broken through the limitations in motion speed, which helps fully unleash the potential of 4D printing.

Study on material distribution and equal-thickness formation mechanism of variable trajectory combined equal-thickness screen

ABSTRACT Equal-thickness screens are widely used in coal processing due to their advantages in overcoming the problems of material accumulation, low utilization of the screen surface, and poor screening accuracy. In this paper, the variable amplitude equal-thickness method was introduced into the combined screen, a novel variable trajectory combined equal-thickness screen was proposed and the combined excitation coefficient was introduced. The motion of the variable trajectory combined equal-thickness screen under different combined excitation coefficients was investigated using vibration test analysis system and the particle motion characteristics and the spatial distributions of materials in the screening process were analyzed using a high-speed camera system. The distribution law of the material was studied by screening experiment. The results show that when the combined excitation coefficient D is increased, the first section screen amplitude increases, the material transport speed of the first section increases, the material accumulation situation of the first section is resolved. When the unbalanced excitation coefficient k is increased, the material layer at the feeding end of each screen becomes thinner, the material transport speed of the first section screen is accelerated, the screen body does variable amplitude elliptical motion, the material is equal-thickness. When D = 1.2, k = 1.2, an optimum screening efficiency of 96.12% was obtained, with a total misplaced material content of only 1.82%.

Tephrostratigraphy of Pleistocene-Holocene deposits from the Detroit Rise eastern slope (northwestern Pacific)

The main goal of the study is to establish the spatial and temporal distribution of pyroclastic material from large explosive eruptions of the volcanoes of Kamchatka, the Kuril, and Aleutian Islands to create a generalized tephrochronological model and reveal patterns of explosive activity in this region. This paper presents new data on the composition of volcanic ash (tephra) found in the Pleistocene deposits of the northwestern Pacific from the eastern slope of the Detroit Rise (northwestern part of the Imperial Ridge), 450–550 km east of the Kamchatka Peninsula. Eleven layers and lenses of tephra aged from 28 to 245 ka, which were previously unknown, were studied in the core Lv63-4-2. Their stratigraphic position and age were determined based on age models developed in this study. Based on the geochemical composition of volcanic glass (determined using an electron microprobe), seven layers were correlated with tephra from several cores in the northwestern Pacific and the Bering Sea. The obtained results supplement the information on large explosive eruptions of volcanoes in the region and their periods of activity. They also allow the development of a generalized tephrochronological model of Quaternary deposits, which is necessary for stratigraphic correlation, and of paleooceanological and paleogeographic reconstructions.

Experimental and computational analysis of polymeric lattice structure for efficient building materials

• A novel building envelop based on spatial distribution of material to form the periodic lattice architecture. • For a given relative density of the lattice, the unit-cell size governs the mode of heat transfer. • The unit-cell orientation plays a significant role in defining the thermal performance of the lattice based structures. • Conductive mode of hear transfer dominates the thermal transmittance of the polymer lattices. A continuous increase in energy prices and the growing concern about global warming has created an urge to increase the energy efficiency of residential buildings. In this paper, the reduction of heat loss by incorporating porosity in a monolithic material was studied. To this aim, various sizes of the polymer-based lattice panels were developed using a triangular unit cell. A new technique based on moulding was used to develop commercial size (1 m 2 ) panels which were not possible with normal 3D printers. A novel, experimental results-based, scaling law was used to predict the thermal performances of these polymer lattice-based panels. Besides, the thermal performance of these lattice-based panels was also investigated using an in-house built calorimeter box and a commercial guard hot box chamber by exposing them to a temperature difference of around 30°C. It was observed that the scaling up of the unit cell size to manufacture commercial-size panels did not affect its U-value; even though the heat transfer through the lattice cell is heavily dependent on the unit cell size. It was also observed that the hydraulic diameter of the polymer-lattice structures of value less than 8mm leads only to a conductive mode of heat transfer. The effect of testing parameters such as sensor location and the temperature gradient across lattice on the U-value of the polymer lattice was also characterised and made recommendations for achieving the higher thermal resistance of the lattice panels to make them suitable for the energy-saving in building applications.

Three-Dimensional Printed Hydroxyapatite Bone Substitutes Designed by a Novel Periodic Minimal Surface Algorithm Are Highly Osteoconductive.

Autologous bone remains the gold standard bone substitute in clinical practice. Therefore, the microarchitecture of newly developed synthetic bone substitutes, which reflects the spatial distribution of materials in the scaffold, aims to recapitulate the natural bone microarchitecture. However, the natural bone microarchitecture is optimized to obtain a mechanically stable, lightweight structure adapted to the biomechanical loading situation. In the context of synthetic bone substitutes, the application of a Triply Periodic Minimum Surface (TPMS) algorithm can yield stable lightweight microarchitectures that, despite their demanding architectural complexity, can be produced by additive manufacturing. In this study, we applied the TPMS derivative Adaptive Density Minimal Surfaces (ADMS) algorithm to produce scaffolds from hydroxyapatite (HA) using a lithography-based layer-by-layer methodology and compared them with an established highly osteoconductive lattice microarchitecture. We characterized them for compression strength, osteoconductivity, and bone regeneration. The in vivo results, based on a rabbit calvaria defect model, showed that bony ingrowth into ADMS constructs as a measure of osteoconduction depended on minimal constriction as it limited the maximum apparent pore diameter in these scaffolds to 1.53 mm. Osteoconduction decreased significantly at a diameter of 1.76 mm. The most suitable ADMS microarchitecture was as osteoconductive as a highly osteoconductive orthogonal lattice microarchitecture in noncritical- and critical-size calvarial defects. However, the compression strength and microarchitectural integrity in vivo were significantly higher for scaffolds with their microarchitecture based on the ADMS algorithm when compared with high-connectivity lattice microarchitectures. Therefore, bone substitutes with high osteoconductivity can be designed with the advantages of the ADMS-based microarchitectures. As TPMS and ADMS microarchitectures are true lightweight structures optimized for high mechanical stability with a minimal amount of material, such microarchitectures appear most suitable for bone substitutes used in clinical settings to treat bone defects in weight-bearing and non-weight-bearing sites.

Влияние пространственного размещения деревьев на плантациях на технологические параметры выборочных рубок

The analysis of the spatial distribution of planting material in different regions during plantation forestry in the context of the geometric parameters of the forest stand is presented, a scheme for growing and harvesting timber on plantations is proposed, the parameters of the forest stand are identified that affect the harmless selective felling of individual trees left for rearing, the possibility is substantiated the use of logging machines in the existing formats of plantations, the requirements for the results of each stage of forest cultivation are formulated, the patented methodology and calculations of the average linear and angular parameters of selective felling are given.

Depositional and diagenetic processes in volcanic matrix‐rich sandstones from the Shanxi and Shihezi formations, Ordos Basin, China: Implication for volcano‐sedimentary systems

AbstractVolcanic eruptions can provide large amounts of sedimentary materials and expose fluvial valleys or lakes to catastrophic hyperpycnal flood events, but this process has not been documented in detail. The Ordos Basin Permian fluvio‐deltaic system reveals evidence for abundant volcanism linked to the tectonic evolution of orogenic belt around the basin and provides a ‘natural laboratory’ for investigating hyperpycnal flows associated with volcanic activity. This study analysed volcanic matrix‐rich sandstone (VMS) samples for petrology, mineralogy and geochemistry in order to address current and uncertain volcanogenic material provenance explanations and the lack of systematic investigations into the depositional and diagenetic processes of volcanic related sediments in the southwestern basin. By combining tectonic background surveys, detrital zircon geochronology and spatial distribution of volcanogenic materials, it was found that volcanogenic materials were not derived from the Yinshan‐Yanshan Orogenic Belt (YYOB) as previously thought, but instead evidence a southwestern origin from the North Qinling Orogenic Belt (NQOB). Volcanogenic materials retained in the provenance area during frequent volcanic eruptions were transported to the basin via fluvial systems shortly after the eruption. The associated sediments meet the criterion for hyperpycnites based on lithofacies associations, suggesting the occurrence of hyperpycnal flows during the deposition of VMS. During the subsequent burial stage, the VMS became three distinct types defined by their volcanic matrix content and have similar paragenetic sequences but different diagenetic intensities. The differing content of authigenic minerals in the three types was closely related to the sandstone pore structure characteristics and the evolution of volcanic‐matrix alteration materials. This article proposes a possible explanation for the previously unidentified tectonothermal events in the NQOB during the Permian, validating and reinforcing the theoretical work of hyperpycnal flow. This contribution provides new insights and understanding of the depositional and diagenetic processes of lacustrine basins with similar tectonic settings.

Pore-Scale Micro-Structural Analysis of Electrode Conductance in Metal Displacement Batteries

Metal displacement batteries (MDBs), or liquid metal batteries, are an emerging technology with significant potential in providing high capacity, low-cost energy storage solutions, capable of addressing many of the challenges associated with storing energy from renewable sources. The key characteristic of metal displacement batteries is that at least one of the electrodes is in liquid state and a molten salt is used as an electrolyte. Since its original proposal in the 1960’s liquid metal batteries have re-emerged in recent years and different battery chemistries and designs have been explored, including Ca-Bi, Na-Sb, and many others [2,10]. Recently, Na-Zn liquid metal batteries have been studied as an alternative to other configurations, showing significant potential in achieving good performance for large-scale energy storage, while avoiding the high cost associated with some electrode materials such as Nickel or Lithium [7,8]. In past years, alternatives to all-liquid cells have emerged in the form of designs where the cell materials are a mixture of solids and liquids. Examples of this include the commercially available Zebra battery, where a Na-NiCl electrode pair is used [1,6]. These designs offer some of the advantages of all-liquid cells, while simultaneously mitigating many of the disadvantages of handling and operating a very high temperature system. Na-Zn have also been proposed for solid cathode designs, taking advantage of the lower cost of Zn over Ni [4,3].The cathode in these designs is composed of a porous structure, within which multiple chemical species can co-exist. Electrolyte components share the space with metal deposits,salt crystals, and other electrochemical reaction products. As a result, the micro-porous structure of this composite system is an important factor in determining the performance of the cell, as the spatial distribution of different materials can have an impact on the effective conductivity of the electrode [5,9]. The porous structure hosts complex multi-component mass transfer phenomena as well, potentially having an impact on the mass-transfer overpotential of the cell.This work aims to study the impact of the microstructural properties of the solid electrode in a liquid displacement battery, and their importance to the effective conductivity of the system. We have developed a computational tool that enables us to create randomized microstructures in 3D, representing the electrode-electrolyte assembly. We are able to preserve the desired physical characteristics by using target pore-size distributions and volume fraction input as seed parameters. We use this tool to generate representative structures and analyze their effective bulk conductivity by solving Laplace’s equation over the resulting domain, accounting for the different local conductivity of each material.This methodology is applied to a novel Na-Zn cell in order to assess the importance of the pore-scale properties of the cathode, as well as its material components, including solid Zn metal, solid NaCl deposits, and molten salt components. It is expected that different material arrangement configurations will induce heterogeneous current distributions in this system. Furthermore, the ionic composition of the electrolyte would be different at different charge levels, leading to additional variation through its charge/discharge cycle.Using this methodology, the range of different electrode phase configurations produced during operation can be studied in the absence of microstructure imaging data. A representative elementary volume for the Zn electrode assembly is analyzed to determine the best approach for up-scaled performance predictions of the Na-Zn cell. With this method, it is possible to acquire data to elucidate desirable or undesirable electrode structure properties of this system, providing insight which can be used for improving manufacture and operation of the cell. [1] Dustmann. “Advances in ZEBRA batteries”. J. Power Sources (2004).[2] Kim et al. “Liquid metal batteries: Past, present, and future”. ChemicalReviews (2013).[3] Lu et al. “An Intermediate-Temperature High-Performance Na-ZnCl2 Bat-tery”. ACS Omega (2018).[4] Lu et al. “Liquid-metal electrode to enable ultra-low temperature sodium-beta alumina batteries for renewable energy storage”. Nature Communications(2014).[5] Qiu et al. “Pore-scale analysis of effects of electrode morphology and electrolyteflow conditions on performance of vanadium redox flow batteries”. J. PowerSources (2012).[6] Sudworth. “The sodium / nickel chloride ( ZEBRA ) battery”. J. Power Sources (2001).[7] Xu et al. “Electrode Behaviors of Na-Zn Liquid Metal Battery”. Journal ofThe Electrochemical Society (2017).[8] Xu et al. “Na-Zn liquid metal battery”. Journal of Power Sources (2016).[9] Zhang et al. “Progress in 3D electrode microstructure modelling for fuel cellsand batteries: transport and electrochemical performance”. Progress in Energy(2019).[10] Zhang et al. “Liquid Metal Batteries for Future Energy Storage”. EnergyEnvironmental Science (2021). Figure 1

Rational designing of MoSe2 nanosheets in carbon framework for high-performance potassium-ion batteries

Carbon-composting is considered as most promising strategy for high-performance anodes of alkali metal ion batteries in viewpoint of improving electric-conductivity and alleviating volume expansion. Spatial distribution of active material in carbon-composting anodes should play a vital role in electron/ion migration, SEI-film growth and stress relief upon ion insertion/extraction. Herein, spatial distribution of MoSe2 in MoSe2/C composites is regulated by controlling the concentration of precursor solutions. Interestingly, uniform distribution of MoSe2 in carbon framework seems to exhibit better cycling-stability than either core-rich MoSe2 or shell-rich MoSe2 composites. In contrast to the suppressed K-ion kinetics in core-rich MoSe2 and the surface cracking in surface-rich MoSe2, homogeneous MoSe2-distribution in MoSe2/C is beneficial for local stress relief, enhanced K+-ion migration and stable SEI-film evolution upon cycling. We believe that the strategy based on spatial distribution of active material in composite would provide novel insights on exploration of high-performance anodes modified with carbon.

A Numerical Measurement Method for Dynamic Granular Materials Based on Computer Vision.

Granular materials are widespread in nature and human production, and their macro-mechanical behavior is significantly affected by granule movement. The development of computer vision has brought some new ideas for measuring the numerical information (including the amount of translation, the rotation angle, velocity, acceleration, etc.) of dynamic granular materials. In this paper, we propose a numerical measurement method for dynamic granular materials based on computer vision. Firstly, an improved video instance segmentation (VIS) network is introduced to perform end-to-end multi-task learning, and its temporal feature fusion module and tracking head with long-sequence external memory can improve the problems of poor video data quality and high similarity in appearance of granular materials, respectively. Secondly, the numerical information can be extracted through a series of post-processing steps. Finally, the effectiveness of the measurement method is verified by comparing the numerical measurement results with the real values. The experimental results indicate that our improved VIS obtains an average precision (AP) of 76.6, the relative errors and standard deviations are maintained at a low level, and this method can effectively be used to measure the numerical information of dynamic granular materials. This study provides an intelligent proposal for the task of measuring numerical information of dynamic granular materials, which is of great significance for studying the spatial distribution, motion mode and macro-mechanical behavior of granular materials.

Geoelectrical imaging and spatial distribution of alluvial materials of the Sanaga River (Cameroon, Central Africa)

Geoelectrical imaging and spatial distribution of alluvial materials of the Sanaga River (Cameroon, Central Africa)

A Model-Based Analysis of Capacitive Flow Metering for Pneumatic Conveying Systems: A Comparison between Calibration-Based and Tomographic Approaches.

Pneumatic conveying is a standard transportation technique for bulk materials in various industrial fields. Flow metering is crucial for the efficient and reliable operation of such systems and for process control. Capacitive measurement systems are often proposed for this application. In this method, electrodes are placed on the conveyor systems transport line and capacitive signals are sensed. The design of the sensor with regard to the arrangement and the number of electrodes as well as the evaluation of the capacitive sensor signals can be divided into two categories. Calibration-based flow meters use regression methods for signal processing, which are parametrized from calibration measurements on test rigs. Their performance is limited by the extend of the calibration measurements. Electrical capacitance tomography based flow meters use model-based signal processing techniques to obtain estimates about the spatial material distribution within the sensor. In contrast to their calibration-based counterparts, this approach requires more effort with respect to modeling and instrumentation, as typically a larger number of measurement signals has to be acquired. In this work we present a comparative analysis of the two approaches, which is based on measurement experiments and a holistic system model for flow metering. For the model-based analysis Monte Carlo simulations are conducted, where randomly generated pneumatic conveying flow patterns are simulated to analyze the sensor and algorithm behavior. The results demonstrate the potential benefit of electrical capacitance tomography based flow meters over a calibration-based instrument design.

Results of the preliminary archaeological excavations of the Plateau of Visočica near the National Monument of the Old Town Visoki in Visoko

This paper presents the results of the preliminary archaeological excavation of the Visočica plateau made in februry 2017, not far from the protected zone of the National monument of Old Town of Visoki. The work took place in a collaboration of Regional museum in Visoko and Institute of archaeology from Faculty of Philosophy in Sarajevo with the aim of examining the archaeological potential of the site and identifying the spatial distribution of material on it. As a result, various archaeological material was discovered, dating from prehistoric period to middle ages.

Surface plasmon enhancement in different spatial distributions of nanowires and two-dimensional materials.

Surface plasmon (SP) nanostructures have been widely researched to improve the low light absorption of two-dimensional transition metal dichalcogenides (TMDCs). However, the impact of their different coupling forms, which is essential for the optimization of nanostructures, has been rarely investigated. Here, we construct two different spatially distributed composite structures of Ag nanowires (NWs) and monolayer (1L) molybdenum disulfide (MoS2). When the Ag NW was buried under 1L MoS2, the formed tiny optical cavity can further promote the light utilization of 1L MoS2, so that the spectral enhancement by SP was stronger than that when the Ag NW was placed on the top of 1L MoS2. In addition, the photoresponsivity and light response speed of the phototransistor based on the composite structure with Ag NWs buried underneath were improved by ∼5-fold and ∼1000-fold, respectively, compared to those of the pristine 1L MoS2 phototransistor. This research provides a reference for the optimization of SP nanostructures to enhance the optoelectronic properties of two-dimensional materials.