bluuebunny/crossref_metadata_2025 huggingface dataset:
Online Administration of the Test of Narrative Language–Second Edition: Psychometrics and Considerations for Remote Assessment
Authors: Magimairaj Beula M. , Capin Philip , Gillam Sandra L. , Vaughn Sharon , Roberts Greg , Fall Anna-Maria , Gillam Ronald B.
Published: January 2022

Purpose:

Our aim was to evaluate the psychometric properties of the online administered format of the Test of Narrative Language–Second Edition (TNL-2; Gillam & Pearson, 2017), given the importance of assessing children's narrative ability and considerable absence of psychometric studies of spoken language assessments administered online.

Method:

The TNL-2 was administered to 357 school-age children at risk for language and literacy difficulties as part of a randomized controlled trial, across three annual cohorts, at three time points (pretest, posttest, and 5-month follow-up). Cohort 3 students were tested using an online format at posttest and at follow-up. We compared the Cronbach's alpha internal consistency reliability of the TNL-2 online testing scores with in-person scores from TNL-2 normative data and Cohort 3 in-person testing at pretest, and interrater reliability for Cohort 3 across test points. In addition, we examined measurement invariance across test occasions and the criterion validity of the TNL-2, the latter based on its correlations with narrative sample measures (Mean Length of Utterance in words and the Monitoring Indicators of Scholarly Language rubric).

Results:

Internal consistency reliability, interrater reliability, and measurement invariance analyses of the online and in-person administration of the TNL-2 yielded similar outcomes. The criterion validity of the TNL-2 was found to be good.

Conclusions:

TNL-2 psychometric properties from online administration were generally in the
good
range and were not significantly different from in-person testing. When administered online using standardized procedures, the TNL-2 is valid and reliable for use in assessing narrative language proficiency in school-age children at risk for language and learning difficulties.
Childhood epilepsy syndromes classification based on fused features of electroencephalogram and electrocardiogram
Authors: Yang Qianlan , Hu Dinghan , Wang Tianlei , Cao Jiuwen , Dong Fang , Gao Weidong , Jiang Tiejia , Gao Feng
Published: January 2022

The paper presents a novel algorithm to classify children's epileptic syndromes based on the fused features of electroencephalogram (EEG) and electrocardiogram (ECG). The purpose is to assess whether multimodal physiological signals could improve the classification performance of epileptic syndromes over a single physiological signal. The study is carried out on the epileptic syndromes database recorded by the Children's Hospital, Zhejiang University School of Medicine (CHZU), that includes the synchronised EEGs and ECGs of 16 children suffered from the infantile spasms (known as the WEST syndrome, named) and the childhood absence epilepsy (CAE), respectively. Experiments are conducted and compared using the EEGs and ECGs in the ictal and interictal periods. The data imbalanced issue between the ictal and interictal periods is also considered by applying a synthetic minority sample generating approach. The experimental results show that using the fused feature of EEG + ECG can achieve an average of 98.15% overall classification accuracy, which is better than using the single physiological signal.
Multi‐agent control in modular motor drives by means of gossip consensus
Authors: Verkroost Lynn , De Belie Frederik , Sergeant Peter , Vansompel Hendrik
Published: January 2022

A modular motor drive (MMD) can be considered as a multi‐agent system, in which the agents work together to reach a common goal. One agent in such an MMD comprises only a subset of the concentrated windings and power electronic converter modules and is equipped with an independent controller. The goal of this research is to let the agents cooperate to distribute a torque demand among them in a completely decentralised way, in order to comply with the flexibility and reliability of modular motor drives. However, the current condition of each agent must still be taken into account during this torque allocation. To limit the communication load, only communication between neighbouring agents is allowed. The combination of a gossip consensus algorithm and multiple decentralised PI current controllers is used for this purpose. Simulations and experimental results on a modular axial‐flux permanent magnet synchronous machine consisting of five agents confirm that the total torque demand is delivered under the proposed control strategy, even during agent malfunctions, under random communication link failures and with non‐identical agents.
Angular momentum transport in a contracting stellar radiative zone embedded in a large-scale magnetic field
Authors: Gouhier B. , Jouve L. , Lignières F.
Published: January 2022

Context. Some contracting or expanding stars are thought to host a large-scale magnetic field in their radiative interior. By interacting with the contraction-induced flows, such fields may significantly alter the rotational history of the star. They thus constitute a promising way to address the problem of angular momentum transport during the rapid phases of stellar evolution.

Aims. In this work, we aim to study the interplay between flows and magnetic fields in a contracting radiative zone.

Methods. We performed axisymmetric Boussinesq and anelastic numerical simulations in which a portion of the radiative zone was modelled by a rotating spherical layer, stably stratified and embedded in a large-scale (either dipolar or quadrupolar) magnetic field. This layer is subject to a mass-conserving radial velocity field mimicking contraction. The quasi-steady flows were studied in strongly or weakly stably stratified regimes relevant for pre-main sequence stars and for the cores of subgiant and red giant stars. The parametric study consists in varying the amplitude of the contraction velocity and of the initial magnetic field. The other parameters were fixed with the guidance of a previous study.

Results. After an unsteady phase during which the toroidal field grew linearly and then back-reacted on the flow, a quasi-steady configuration was reached, characterised by the presence of two magnetically decoupled regions. In one of them, magnetic tension imposes solid-body rotation. In the other, called the dead zone, the main force balance in the angular momentum equation does not involve the Lorentz force and a differential rotation exists. In the strongly stably stratified regime, when the initial magnetic field is quadrupolar, a magnetorotational instability is found to develop in the dead zones. The large-scale structure is eventually destroyed and the differential rotation is able to build up in the whole radiative zone. In the weakly stably stratified regime, the instability is not observed in our simulations, but we argue that it may be present in stars.

Conclusions. We propose a scenario that may account for the post-main sequence evolution of solar-like stars, in which quasi-solid rotation can be maintained by a large-scale magnetic field during a contraction timescale. Then, an axisymmetric instability would destroy this large-scale structure and this enables the differential rotation to set in. Such a contraction-driven instability could also be at the origin of the observed dichotomy between strongly and weakly magnetic intermediate-mass stars.
Application of the Consolidated Framework for Implementation Research Model to Design and Implement an Optimization Methodology within an Ambulatory Setting
Authors: Touson Jonathan C. , Azad Namita , Beirne Jennifer , Depue Corinne R. , Crimmins Timothy J. , Overdevest Jonathan , Long Rosalie
Published: January 2022

Background Following the implementation of a new electronic health record (EHR) system at Columbia University Irving Medical Center (CUIMC), the demands of the novel coronavirus disease 2019 (COVID-19) pandemic forced an abrupt reallocation of resources away from EHR adoption. To assist staff in focusing on techniques for improving EHR utilization, an optimization methodology was designed referencing the Consolidated Framework for Implementation Research (CFIR) approach.

Methods The study was performed using a methodology that comprised of two primary components as follows: (1) analysis of qualitative and quantitative data and (2) participation of frontline staff in project work groups. Working groups mapped out the current state of the identified workflows, designed and implemented interventions, monitored the effectiveness of each intervention, and scaled the proposed changes.

Results As a result of the optimization methodology, clinical and operational workflows improved in the pilot department. Operationally, the pilot department increased enrollment of patients in the virtual patient portal by 20%, increased schedule utilization by 25%, and reduced average check-in time by 19%. Clinically, the pilot department had a statistically significant increase in dictation and NoteWriter tool note composition from their baseline month to their observed month. Compared with the control department, the pilot department had a statistically significant increase in SmartTool and dictation note composition. The control department showed smaller increases, and in some cases a decline in performance, in these areas of operational and clinical workflows.

Conclusion The CFIR framework helped design an optimization methodology by applying a set of constructs to support effective organizational optimization, accounting for inner and outer settings. Through this methodology, the inner setting was supported in leading the identification and execution of interventions targeted to impact the outer setting. The phase-1 data at CUIMC suggest this strategy is effective in identifying opportunities, implementing interventions and creating a scalable process for continued organizational optimization.
Three-dimensional free-energy landscape of hydrogen and oxygen molecules in polymer electrolyte membranes: Insight into diffusion paths
Authors: Nagai Tetsuro , Fujimoto Kazushi , Okazaki Susumu
Published: January 2022

Polymer electrolyte membranes, for example, the Nafion™ membranes, used in the fuel cells are responsible for separating reactive gas molecules as well as for the efficient exchange of protons. Although control of the permeation of the gases is important to enhance the fuel cell performance, the mechanism by which hydrogen and oxygen molecules permeate through the membranes remains unclear. To clarify the mechanism, we investigated the three-dimensional free-energy landscape of hydrogen and oxygen molecules in Nafion membranes with various water contents focusing on relevant diffusion paths. Low-free-energy paths are found mainly in the polymer phase and the interfacial region between the polymer and water phases. Thus, the path of the transportation may be attributed to the polymer phase and interfacial phases. However, the free-energy value in the aqueous phase is only slightly higher (∼1–2 kBT) than that in the other two phases, which indicates that a secondary contribution from the aqueous phase is expected. The free-energy landscape in the polymer and interfacial phases was found rugged, while it is comparatively flat in the water phase. We also found that an increase in water content brings about a smoother free-energy landscape in the polymer and interfacial phases. The decreased ruggedness may facilitate the gas diffusivity. These observations help understand the molecular mechanism of the gas diffusion in the membranes.
Interfacial dynamics in inverted-headgroup lipid membranes
Authors: Lee Euihyun , You Xiao , Baiz Carlos R.
Published: January 2022

Inverted-headgroup (choline-phosphate) lipids are synthetic lipids that are not found in nature and are used as model systems to understand the role of headgroup dipole orientation. Recently, studies revealed that the net orientation of interfacial water strongly depends on the headgroup electrostatics, i.e., the charges and dipole generated by the phosphate and the choline groups. In order to characterize interfacial H-bond dynamics, we measured two-dimensional infrared spectra of the ester carbonyl band and performed molecular dynamics simulations in fully hydrated 1,2-dioleoyl-sn-glycero-3-phosphocholine and 2-((2,3-bis(oleoyloxy)propyl)-dimethyl-ammonio)ethyl ethyl phosphate (DOCPe) lipid bilayers. The experiments and simulations suggest that the reverse dipole generated by the inverted-headgroup in DOCPe does not affect the carbonyl H-bond populations or the interfacial water H-bond dynamics. However, while phosphate-associated waters in both lipids appear to show a similar H-bond structure, carbonyl-associated waters are characterized by a slightly disrupted H-bond structure in the DOCPe bilayer, especially within the second hydration shell. Our findings show that changes in net water orientation perturb the water H-bonds at the linker region between the headgroup and the lipid tail, although this perturbation is weak.
Guide to Native Orchids of NSW and ACT
Authors: Copeland Lachlan , Backhouse Gary
Published: January 2022

This comprehensive guide describes the 582 species of wild orchids that occur in NSW and the ACT. This region covers the richest area for wild orchids in Australia and includes over 500 species of seasonal ground orchids and 62 species of evergreen tree and rock orchids. Orchids found in this region include the tallest, heaviest, smallest flowered, most numerous flowered and most bizarre orchids in Australia, including elusive underground species.

Guide to Native Orchids of NSW and ACT describes each species, enabling their identification in the field, and includes over 600 photographs of wild orchids in their natural habitat and distribution maps for almost all species. Featuring orchids with a dazzling array of colour and form, this is the essential guide for all orchid enthusiasts.
Bosonic Halperin (441) Fractional Quantum Hall Effect at Filling Factor ν = 2/5
Authors: Zeng Tian-Sheng , Hu Liangdong , Zhu W.
Published: January 2022

Quantum Hall effects with multicomponent internal degrees of freedom facilitate the playground of novel emergent topological orders. Here, we explore the correlated topological phases of two-component hardcore bosons at a total filling factor ν = 2/5 in topological lattice models under the interplay of intracomponent and intercomponent repulsions. We give the numerical demonstration of the emergence of Halperin (441) fractional quantum Hall effect based on exact diagonalization and density-matrix renormalization group methods. We elucidate its topological features including the degeneracy of the ground state, fractionally quantized topological Chern number matrix and chiral edge modes.
In-Plane Magnetization-Induced Corner States in Bismuthene
Authors: Han Bin , Zeng Junjie , Qiao Zhenhua
Published: January 2022

We theoretically demonstrate that the electronic second-order topological insulator with robust corner states, having a buckled honeycomb lattice, can be realized in bismuthene by inducing in-plane magnetization. Based on the sp
3 Slater–Koster tight-binding model with parameters extracted from first-principles results, we show that spin-helical edge states along zigzag boundaries are gapped out by the in-plane magnetization whereas four robust in-gap electronic corner states at the intersection between two zigzag boundaries arise. By regulating the orientation of in-plane magnetization, we show different position distribution of four corner states with different energies. Nevertheless, it respects some spatial symmetries and thus can protect the higher-order topological phase. Combined with the Kane–Mele model, we discuss the influence of the magnetization orientation on the position distribution of corner states.
Flexible force sensitive frequency reconfigurable antenna base on stretchable conductive fabric
Authors: Shao Li , Tang Xinyue , Yang Yujie , Wei Dacheng , Lin Yuanchang , He Guotian , Wei Dapeng
Published: January 2022

With the development of wireless technology and flexible electronics, flexible frequency reconfigurable antennas have been directly used as sensors to detect mechanical signals. As an important frequency reconfigurable antenna, microstrip antenna has been widely studied in the field of flexible and flexible electronics in recent years. However, the stretchability of microstrip antennas usually comes at the cost of reducing the conductivity of the radiated conductor. Here, we report a flexible force sensitive frequency reconfigurable microstrip antenna, which fabricated by silver fiber conductive fabric with a double-wire braided structure. In order to increase the detection of pressure, an elastic dielectric layer with a microhemispheric array was introduced into the microstrip antenna to extend the frequency band width of the reconfigurable antenna. The relative frequency of the antenna varied from 0% to −12.9%, and the sensing sensitivity was −1.9 kPa−1. As potential applications, we demonstrate the use of a flexible frequency reconfigurable antenna base on stretchable conductive fabric as a strain sensor capable of measuring bending angle and movements of a human finger. The change in the resonance frequency with the externally applied tensile strain in this antenna design has a sensitivity of 3.448, manifesting a 4.19- and a 13.79-fold increase of sensitivity when compared to those in previous reports that used arched or both-planes serpentine rectangular microstrip antenna. This is of great significance for the application of wearable antenna in wireless mechanical sensing technology.
Spinodal de-wetting of light liquids on graphene
Authors: Vanegas Juan M , Peterson David , Lakoba Taras I , Kotov Valeri N
Published: January 2022

We demonstrate theoretically the possibility of spinodal de-wetting in heterostructures made of light–atom liquids (hydrogen, helium, and nitrogen) deposited on suspended graphene. Extending our theory of film growth on two-dimensional (2D) materials to include analysis of surface instabilities via the hydrodynamic Cahn–Hilliard-type equation, we characterize in detail the spatial and temporal scales of the resulting spinodal de-wetting patterns. Both linear stability analysis and direct numerical simulations of the surface hydrodynamics show micron-sized (generally material dependent) patterns of ‘dry’ regions. The physical reason for the development of such instabilities on graphene can be traced back to the inherently weak van der Waals interactions between atomically thin materials and atoms in the liquid. Thus 2D materials could represent a new theoretical and technological platform for studies of spinodal de-wetting.
BAIRDA: a novel in vitro setup to quantify radiobiological parameters for cervical cancer brachytherapy dose estimations
Authors: Chow Braden , Warkentin Brad , Nanda Kareena , Ghosh Sunita , Huang Fleur , Gamper Armin M , Menon Geetha
Published: January 2022

Objective. Brachytherapy (BT) dose prescriptions for locally advanced cervical cancer are made with account for the radiobiological parameters,α/βratio and halftime of repair (T1/2). However, a wide range of parameter values has been reported which can challenge commonly held equivalencies between dose prescriptions. This is the first reported study that aims to develop anin vitroexperimental technique using clinical high-dose-rate (HDR) and pulsed-dose-rate (PDR) Ir-192 brachytherapy afterloaders to quantify these parametersin vitroand to contextualize findings within contemporary practice.Approach. To efficiently quantifyα/βandT1/2,in vitroexperiments more reflective of clinical BT practice than traditional clonogenic survival assays were developed and applied to four squamous cell carcinoma cell lines (CaSki, C-33A, SiHa, and SW756). Radiation was delivered using single acute and fractionated dose treatments with a conventional irradiator and clinical HDR and PDR BT afterloaders. For the latter, a novelbrachytherapyafterloaderin vitroradiationdeliveryapparatus (BAIRDA) was developed.Main Results. Theα/βandT1/2values determined using BAIRDA and the conventional irradiator showed close agreement, validating the novel apparatus and technique. For CaSki, C-33A, SiHa, and SW756, the BAIRDA-measuredα/βratios (5.2 [4.6–5.8], 5.6 [4.5–6.6], 6.3 [4.9–7.7], and 5.3 [4.7–6.0] Gy, respectively) were consistently smaller, while theT1/2(3.3 [2.7–3.9], 2.7 [2.0–3.3], 2.8 (2.4–3.1], and 4.8 [4.1–5.4] hours) larger, than the widely accepted values in clinical practice (α/β= 10 Gy;T1/2 = 1.5 h).Significance.In vitroexperiments using BAIRDA provided evidence for differences between the conventionally selected and experimentally determinedα/βratio andT1/2. Treatment regimens using HDR-BT and PDR-BT, designed to deliver equivalent radiobiological doses based on conventional values, were shown to differ by up to 27 Gy EQD2 – an effect that could impact treatment outcomes in cervical cancer. Furthermore, with BAIRDA, we have developed a novel method for radiobiological research in BT.
Quad-band terahertz metamaterial absorber using three parallel gold strips surrounded by two identical gold ring arcs
Authors: Lai Shengxiong , Xu Wei , Yang Zhuchuang , Lu Liming , Wang Kun , Feng Sen , Zhang Sijian , Wu Yangkuan , Wang Ben-Xin
Published: January 2022

Quad-band terahertz metamaterial absorber with near-perfect absorption is given in this paper. It is designed by a patterned Au layer and a continuous Au film separated by an insulating dielectric layer, of which the patterned Au layer is consisted of three parallel Au strips (a longer and two shorter) surrounded by two Au ring arcs of the same size. Four separated terahertz absorption peaks with narrow bandwidths and large absorptance are realized. The first three absorption peaks are due to the fundamental modes of the Au strips and the Au ring arcs, while the fourth absorption peak is ascribed to the excitation of three-order resonance in the Au ring arcs. The field distributions of the four absorption peaks are presented to verify their physical mechanisms. The influence of geometrical dimensions of the proposed configuration on the performance of the quad-band light absorption is discussed. Moreover, considering the potential sensing applications, the sensing performance of the proposed absorption device is also explored. The suggested scheme could provide considerable application prospects in selective thermal radiation, spectral imaging, sensing, detecting, electromagnetic stealth, etc.
Prospects for measuring dark energy with 21 cm intensity mapping experiments
Authors: Wu Peng-Ju , Zhang Xin
Published: January 2022

Using the 21 cm intensity mapping (IM) technique can efficiently perform large-scale neutral hydrogen (HI) surveys, and this method has great potential for measuring dark-energy parameters. Some 21 cm IM experiments aiming at measuring dark energy in the redshift range of 0<z<3 have been proposed and performed, in which the typical ones using single-dish mode include e.g., BINGO, FAST, and SKA1-MID, and those using interferometric mode include e.g., HIRAX, CHIME, and Tianlai. In this work, we make a forecast for these typical 21 cm IM experiments on their capability of measuring parameters of dark energy. We find that the interferometers have great advantages in constraining cosmological parameters. In particular, the Tianlai cylinder array alone can achieve the standard of precision cosmology for the ΛCDM model (i.e., the precision of parameters is better than 1%). However, for constraining dynamical dark energy, we find that SKA1-MID performs very well. We show that the simulated 21 cm IM data can break the parameter degeneracies inherent in the CMB data, and CMB+SKA1-MID offers σ(w)=0.013 in the wCDM model, and σ(w
0)=0.080 and σ(w
a)=0.25 in the CPL model. Compared with CMB+BAO+SN, Tianlai can provide tighter constraints in ΛCDM and wCDM, but looser constraints (tighter than CMB+BAO) in CPL, and the combination CMB+BAO+SN+Tianlai gives σ(w)=0.013, σ(w
0)=0.055, and σ(w
a)=0.13. In addition, it is found that the synergy of FAST (0<z<0.35)+SKA1-MID (0.35<z<0.77)+Tianlai (0.77<z<2.55) offers a very promising survey strategy. Finally, we find that the residual foreground contamination amplitude has a considerable impact on constraint results. We show that in the future 21 cm IM experiments will provide a powerful probe for exploring the nature of dark energy.
The observed galaxy power spectrum in General Relativity
Authors: Castorina Emanuele , Di Dio Enea
Published: January 2022

Measurements of the clustering of galaxies in Fourier space, and at low wavenumbers, offer a window into the early Universe via the possible presence of scale dependent bias generated by Primordial Non Gaussianites.
On such large scales a Newtonian treatment of density perturbations might not be sufficient to describe the measurements, and a fully relativistic calculation should be employed. The interpretation of the data is thus further complicated by the fact that relativistic effects break statistical homogeneity and isotropy and are potentially divergent in the Infra-Red (IR).
In this work we compute for the first time the ensemble average of the most used Fourier space estimator in spectroscopic surveys, including all general relativistic (GR) effects, and allowing for an arbitrary choice of angular and radial selection functions. We show that any observable is free of IR sensitivity once all the GR terms, individually divergent, are taken into account, and that this cancellation is a consequence of the presence of the Weinberg adiabatic mode as a solution to Einstein's equations. We then study the importance of GR effects, including lensing magnification, in the interpretation of the galaxy power spectrum multipoles, finding that they are in general a small, less than ten percent level, correction to the leading redshift space distortions term. This work represents the baseline for future investigations of the interplay between Primordial Non Gaussianities and GR effects on large scales and in Fourier space.
Plasmon-induced transparency effect in hybrid terahertz metamaterials with active control and multi-dark modes
Authors: Zhang Yuting , Liu Songyi , Huang Wei , Dong Erxiang , Li Hongyang , Shi Xintong , Liu Meng , Zhang Wentao , Yin Shan , Luo Zhongyue
Published: January 2022

We numerically demonstrate a photo-excited plasmon-induced transparency (PIT) effect in hybrid terahertz (THz) metamaterials. The proposed metamaterials are regular arrays of hybrid unit cells composed of a metallic cut wire and four metallic split-ring resonators (SRRs) whose gaps are filled with photosensitive semiconductor gallium arsenide (GaAs) patches. We simulate the PIT effect controlled by external infrared light intensity to change the conductivity of GaAs. In the absence of photo excitation, the conductivity of GaAs is 0, thus the SRR gaps are disconnected, and the PIT effect is not observed since the dark resonator (supported by the hybrid SRRs) cannot be stimulated. When the conductivity of GaAs is increased via photo excitation, the conductivity of GaAs can increase rapidly from 0 S/m to 1 × 106 S/m and GaAs can connect the metal aluminum SRR gaps, and the dark resonator is excited through coupling with the bright resonator (supported by the cut wire), which leads to the PIT effect. Therefore, the PIT effect can be dynamically tuned between the on and off states by controlling the intensity of the external infrared light. We also discuss couplings between one bright mode (CW) and several dark modes (SRRs) with different sizes. The interference analytically described by the coupled Lorentz oscillator model elucidates the coupling mechanism between one bright mode and two dark modes. The phenomenon can be considered the result of linear superposition of the coupling between the bright mode and each dark mode. The proposed metamaterials are promising for application in the fields of THz communications, optical storage, optical display, and imaging.
Thermodynamics for higher dimensional rotating black holes with variable Newton constant *
Authors: Zhao Liu
Published: January 2022

The extensivity for the thermodynamics of general D-dimensional rotating black holes with or without a cosmological constant can be proved analytically, provided that the effective number of microscopic degrees of freedom and the chemical potential are given respectively as

, where G is the variable Newton constant,

is the Euclidean action, and L is a constant length scale. In the cases without a cosmological constant, i.e., the Myers-Perry black holes, the physical mass and the intensive variables can be expressed as explicit macro state functions in the extensive variables in a simple and compact form, which allows for an analytical calculation of the heat capacity. The results indicate that the Myers-Perry black holes with zero, one, and k equal rotation parameters are all thermodynamically unstable.
Investigation of the control characteristics of mineral processing technology indicators
Authors: Pryadko Nataliya , Mladetsky Igor , Dziuba Serhii , Ternova Kateryna
Published: January 2022

The analysis of the reduce possibilities of the production and energy costs is carried out from the control view of the material size and the testing characteristics of the technological mineral processing process. Correct sampling results show the distribution of valuable components in the ore, and then the concentration process improves the concentrate quality. A method of selecting massif pieces in order to form a representative sample is considered. There are determined the dependence of the change in the distribution function of intergrowths on the material size and the dependence of the sample mass on the texture and structural ore properties, i.e. the content of valuable material and the content of ore grains in the ore. Studies have shown that with a change in the piece size, there is a change in the limiting values of the magnetite content in them. Improving the concentrate quality depends on the size of the processing products, for the control of which a method is proposed for determining the distribution function by size class in accordance with the lognormal law for finely dispersed materials, regardless of their physical properties.
Rhenium recovery from sulfuric media using AMR anionite
Authors: Korovin Vadym , Pohorielov Yurii , Shestak Yurii , Valiaiev Oleksandr , Cortina Jose-Luis
Published: January 2022

The paper deals with equilibrium and kinetics of rhenium sorption using AMR weak-base anionite from simulated sulfuric solutions with high and low acidity. A comparative analysis was carried out for Freundlich, Langmuir and Sips sorption models. It was found out that equilibrium experimental data fitted with the highest determination factor by the Sips equation from solutions with high acidity and by the Henry one for low acidic solutions. A comparative analysis was carried out for sorption kinetics using different kinetic models; the values were estimated for calculated effective factors of intra-particle diffusion and model approximation to experimental data. To assess the contribution of chemical interaction in the rhenium sorption process, kinetics data were quantitatively approximated using pseudo-first order, pseudo-second order and Elovich kinetic models. It was found that the pseudo-second order model fits experimental data most accurately. Results were given on rhenium stripping by ammonia solution. The results obtained may be used for rhenium recovery from washing sulfuric acid in the systems of wet dust and gas scrubbing during pyrometallurgical processing of copper ore concentrates and other acidic industrial solutions as well as liquors after uranium sorption.
Co — Ni — Zn nanoferrites: magnetic and photocatalytic properties for the decomposition of 4-nitrophenol
Authors: Frolova Liliia , Tsepich Olena
Published: January 2022

The paper considers changes in the magnetic and catalytic properties of Co- Ni- Zn ferrites by drawing up plans Scheffe’s plans. Three-component ferrites were obtained using coprecipitation and glow dischage treatment. It was found that the saturation magnetization decreases for Ni- Zn ferrites with increasing Zn content, high values for the entire series of Co- Zn, Co-Ni ferrites are observed. The study of catalytic activity in relation to the decomposition reaction of 4-nitrophenol showed excellent results for all compositions. The effect of the mutual influence of the content of different cations on the photocatalytic properties is clearly traced. Ferrites containing one cation in the composition have lower photocatalytic activity. Using UV-spectroscopy, the mechanism of 4-nitrophenol (4-NP) degradation was established.
Optimization of hydrogeological monitoring in the coal-mining region of Western Donbass
Authors: Yevhrashkina Halyna , Kharytonov Mykola , Shikula Elena , Lemishko Svitlana
Published: January 2022

The results of the solutions for assessing the degree of reliability compared with the results of regime observation network, water balance hydrogeological stations and key sites created for it. Epignous tasks occupy a special place in the optimization of hydrogeological monitoring of coal-mining regions. The “disordered dispersion” scheme should recognized as the most reliable after numerous numerical experiments to solve the problems of assessing the technogenic pollution of groundwater in the conditions of Western Donbas. The direct forecasting problem for various periods before the stabilization time was determined and solved at the final stage.
Geomechanical monitoring of pit edge massif deformations of open-pit coal mines on ground-based laser scanning
Authors: Rakhimov Sherzod , Nizamova Albina
Published: January 2022

The laser scanning method, used in combination with traditional mine surveying observations, is one of the most effective and safe ways to conduct surveying and instrumental observations on deforming areas of open-pit mining facilities. The article presents the results of ground-based laser scanning of the “Haranutsky” coal pit and performs a comparative analysis to determine the deformations and displacements of the open pit side for different periods, which was performed in the RISCAN PRO environment. Digital Relief Models (DRM) were constructed to distinguish the observation cycles by colors. Based on the results of the monitoring, it was concluded that no critical displacements and deformations were detected, despite the places of small scree deposits in the rock massif, and further systematic observations were recommended.
Mathematical model of porous solid impregnation based on multichannel representation of the pore system
Authors: Yelisieiev Volodymyr , Lutsenko Vasyl , Berkout Vadim
Published: January 2022

In this work, based on the development of previously constructed concepts of modeling the process of impregnation of porous media with an unknown pore structure, a mathematical model was developed for calculation the change in water absorption of a body immersed in a liquid. The model is based on considering a porous structure in the form of a system of unconnected channels of three different radii. Using a theoretical model and experimental data approximations, the corresponding curves characterizing the truncated radial distribution of porous channels were obtained. Satisfactory agreement with experimental data was obtained for various porous materials. The presented calculations showed that, despite the roughness of the assumptions in the theory of fluid motion through pore channels and the pore system itself, the idea of multichannel is quite justified. It is possible that the variety of channels and their sizes determine mainly the fractal properties of the impregnated samples. The accepted scheme of pore channels shows somewhat underestimated values of the diameters of the middle channels. This indicates the need to include in the structure at least one more parameter, for example, tortuosity, in order to approximate the real characteristics of porous materials.
Study results of the hydroimpulsive loosening of coal-seams at the active stage
Authors: Zberovskiy Vasyl , Pazynich Artem , Zmiievska Kristina , Vlasenko Vasyl
Published: January 2022

The paper deals with the research of fluid impulse injection on a hydraulic stand and the results of mining-experimental studies of cavitation fluid flow dynamic parameters. The defined reliance between frequency and amplitude of self-oscillations on pressure of the liquid boosting in the filtration part of well simulator are considered. It is determined that the regime of periodic disruptive flow of fluid occurring in the filtration part of the well has the following stages: development, constant and damped cavitation. The active stage of hydroimpulsive loosening of outburst-prone coal seams and working ranges of hydroimpulsive action device according to the double amplitude and frequency of self-oscillations of fluid pressure in the well are established.
Regularities of the deformed state of the geotechnical system “soil base – micropile”
Authors: Petrenko Volodymyr , Bannikov Dmytro , Kharchenko Vitalii , Tkach Taisiia
Published: January 2022

Definition and predicting the deformed state of the geotechnical system “soil base – micropile” are the relevant scientific and technical objective when strengthening the soil base by reinforcing elements. The complexity of solving such a problem lies in the heterogeneity of the deformation characteristics for the parts of the specified system. The application of mathematical modeling based on the finite-element method allows defining the behavior of the deformed state in the geotechnical system “soil base – micropile” in the variation of the elastic modulus of its elements. In the course of the numerical analysis of twenty finite-element models characterized by a change in the elastic modulus of the micropile material and soil base, the value of maximum vertical displacements of the strip foundation for the civil structure is obtained. The generalization of these values makes it possible to construct diagrams of their changes in accordance with the variation of the elastic modulus. The obtained regularities allow predicting a deformed state for a sufficiently wide range of the elastic modulus for elements in the system “soil base – micropile”.
Comparative analysis of the VPR-4M vibrating feeder dynamics for the reflected ore output from the outlets and its modernized analog with a vibro-impact adaptive drive
Authors: Shevchenko Volodymyr , Shevchenko Heorgii , Zozulia Halyna , Pukhalskyi Victor
Published: January 2022

A study has been conducted on the developed mathematical model of the VPR-4M vibrating feeder oscillations, which is used for the output and loading of reflected ore from the outlets at underground mining and its modernized analog with a vibro-impact adaptive drive. It is shown that at the same excitation parameters the intensity of the feeder tray oscillations with vibro-impact drive exceeds the intensity of the VPR-4M feeder tray oscillations, which leads to an increase in the transportation speed and ore leakage. With increasing load from the ore on the trays there is an increase in the oscillation parameters of the vibro-impact drive, which leads to more intense oscillations of the feeder tray with vibro-impact drive in comparison with the oscillations of the VPR-4M feeder. The vibrating system of the feeder with vibro-impact adaptive drive performs polyfrequency oscillations, which leads to increased intensity and distance of oscillation spreading in the ore. The identified advantages increase the efficiency and productivity of vibration output by increasing the speed of ore transportation through the tray, intensifying its leakage from the outlet and reducing the probability of ore hangs due to increasing intensity and oscillation distance through the ore in the outlet.
Financial leasing for the extractive industry: status and trends
Authors: Vnukova Nataliya , Tokhtamysh Tetiana , Hranko Kateryna , Sokol Sergii
Published: January 2022

The article proves the necessity and expediency of using financial leasing by extractive industry enterprises to minimize the cost of purchasing, using, maintaining equipment and maintaining production capacity. Foreign and domestic financial leasing practices analyzed and their direct impact on the development of the country’s economy is determined. Financial leasing will become more accessible and understandable for enterprises of different sectors of the economy after the entry into force of the Law of Ukraine “On Financial Leasing”. The analysis of the value of the concluded financial leasing agreements by sectors of the economy carried out and their basic tendencies defined. It is determined that the volume of concluded financial leasing agreements by extractive industry enterprises has a small share in comparison with other branches of economy. The analysis of the effectiveness of structural changes confirm the low demand for financial leasing by extractive industry enterprises. It is determined that the use of financial leasing by extractive industry enterprises will expand existing production, introduce the latest technologies, minimize costs for the purchase, use, maintenance and upgrade of equipment and means of production.
Numerical model for evaluation efficiency of coal pile wetting
Authors: Biliaiev Mykola , Biliaieva Viktoriia , Kozachyna Vitalii , Berlov Oleksandr , Gunko Olena , Rusakova Tetiana
Published: January 2022

Wetting the surface of coal piles is a common method of reducing dust emissions. The problem of modeling air pollution near coal after its wetting is considered. A two-dimensional mass transfer equation was used to model the process of coal dust distribution from the pile. This equation takes into account the convective and diffusion transport of coal dust in the atmosphere. The developed mathematical model takes into account different emission rates of coal dust from different parts of the coal pile. The model takes into account the effect of water evaporation from the coal pile on the rate of intensity of coal dust emission. A potential flow model was used to model the wind flow over the coal pile. Finite-difference splitting schemes have been used for numerical integration of modeling equations. Computer code based on the proposed numerical model has been developed. The developed code can be used to predict the efficiency of wetting coal piles over time. The results of a computational experiment are presented.
Technology for mining of complex-structured bodies of stable and unstable ores
Authors: Pysmennyi Serhii , Fedko Mykhailo , Chukharev Serhii , Rysbekov Kanay , Kyelgyenbai Khavalbolot , Anastasov Dimitar
Published: January 2022

The object of the study is a rock massif represented by complex-structured ore bodies mined by underground systems with open stoping or systems with bulk caving. Deposits of Kryvyi Rih iron ore basin are represented by different types of ferruginous quartzite, which enables application of a great number of mining systems to mining blocks. There are also barren rock inclusions within the block which are extracted from the block along with ore, and this reduces the iron content of the mined ore mass. Findings of the comprehensive study enable concluding that application of the selective method when mining a deposit can enhance recovery rates. Analysis of methods for determining rock stability results in ascertaining that in case of a 4–7 m thick inclusion of barren rocks it is advisable to use a system with bulk caving at a single stage, and in case of a 7–12 m thick inclusion – in two stages. The first stage involves mining the hanging wall reserves, the footwall reserves are mined at the second stage. This method is distinguished by leaving a barren rock inclusion in the block. The developed options of the mining system allow increasing the iron content in the mined ore mass by 2–4% and obtaining the expected economic effect from 3.0 M to 30.2 M USD depending on mining and geological conditions.
Heading set of equipment for underground development galleries drivage in rocks prone to gas-dynamic phenomena
Authors: Minieiev Serhii , Vasyliev Leonid , Trokhymets Mykola , Maltseva Vira , Vialushkin Yehor , Moskalova Tetiana
Published: January 2022

The article presents the design of the heading set of equipment for drivage of development galleries in rocks prone to gas-dynamic phenomena. This equipment can carry out the full technological cycle of rock excavation. The use of the P-110 roadheader of Ukrainian PJSC “Novokramatorskyi Machine Building Plant” with an operating device on a telescopic boom is offered for the aggregation of the heading set of equipment for underground development galleries drivage in emission-hazardous rocks. The device for mechanized boreholes drilling in an emission-hazardous coal seam has been devised based on the EBGP-1 M drilling machine of the Ukrainian SPA “Chervonyi Metalist Co Ltd”. This device is placed on the telescopic boom of the roadheader. For mechanized drilling of explosive, degassing, unloading and injection boreholes, a rock-breaking tool has been proposed that can perform an effective vibratory and rotary loading method of drilling in medium-hard and hard rocks. Safe methods for underground development galleries drivage in gas-bearing emissionhazardous rocks have been worked out. The effectiveness of these methods was determined in industrial conditions. It is possible to conclude that this new heading set of equipment and technology can be recommended for implementation in the mining coal industry.
Energy of low-temperature plasma in the processes of thermal conversions of carbon-containing medium
Authors: Bulat Anatolii , Kholiavchenko Leonid , Oparin Serhii , Davydov Serhii , Zhevzhyk Oleksandr , Potapchuk Iryna
Published: January 2022

One alternative for solving negative environmental impact is to use alternative renewable energy sources. However, technology is evolving and nowadays it cannot meet the needs of emerging economies. A promising direction in the field of clean technologies is the preliminary preparation of carbon-containing media of various origins by thermoconverting them into a gaseous state in high temperature fields. The analysis of the existing autothermal and allottermic technologies of gasification of carbonaceous media is given in the work. The advantages of allottermic technologies of high-temperature transformations under the action of arc plasma with steam oxidizing medium are presented. This method includes plasma formation processes, which combine in time and space thermal transformations and the generation of oxidant from water. The results of theoretical studies of the carbon-containing media plasma transformation process is presented in the article. The regularities of the temperature of steam-plasma transformation process influence on the qualitative and quantitative indicators of the obtained gas phase taking into account the medium elemental composition are established. Comparison of the cost indicators of production of synthetic motor fuel from natural gas by the known companies and from coal by steam-plasma conversion to gas is carried out.