Block Model Research Articles

The impact of discontinuities on spalling failure in excavations under high-stress conditions

The Continuum Voronoi Block Model (CVBM), a pseudo-discontinuum modeling technique based on the Finite Element Method, was employed to investigate the impact of discontinuities on spalling phenomena around excavations in rocks under high-stress conditions. The CVBM’s ability to produce numerical results consistent with spalling was demonstrated through a case study of the Mine-by tunnel. The results show that the model can explicitly capture the formation of macro-fractures parallel to excavation walls, intact rock slabs, and V-shaped notches. The results of this case study support the application of CVBM for parametric analyses to investigate the role of discontinuities in spalling failure, integrating discrete fracture network (DFN) into the model. The influence of DFN parameters such as dip angle, spacing, persistence, position, and mechanical properties is also evaluated. It was found that discontinuities promote stress relief due to shear, thereby altering spalling damage around the excavation in highly stressed rock. This finding highlights the crucial role of discontinuities in influencing the behavior of excavations under such conditions.

Research on the Effects of Spatial Forms in Residential Blocks on Road Traffic Noise Distribution in Typical City of China

Integrating the block system into construction is the current trend in the development of residential areas in China. Road traffic noise is the major noise source in residential blocks, and its relationship with spatial forms of blocks remains unclear. In this study, 852 block models (258 block road network models and 594 models with buildings inside) were established and simulated with SoundPLAN 8.2 software, in order to reveal the impact of spatial forms (road network morphology, neighborhood scale, and architectural texture) on the road traffic noise distribution in residential blocks. Meantime, a prediction model based on spatial morphology parameters is proposed. It was found that (1) Without considering the impact of buildings, both the road network morphology and neighborhood scale parameters have significant effects on the distribution of road traffic noise, but road network morphology has a larger effect than neighborhood scale. (2) In the presence of buildings within the block, architectural texture parameters have effects on the distribution of road traffic noise, but to a lesser extent than road network morphology and neighborhood scale parameters. (3) This research employs principal component analysis to reduce the dimensionality of urban spatial form parameters. Subsequently, a model was developed to predict overall noise exposure levels in residential areas, which was validated by example. This model can be used as a tool for rapid prediction and diagnosis of the block acoustic environment. These findings offer insights for the planning and design of residential blocks from the perspective of optimizing the acoustic environment.

Investigating Different Interpolation Methods for High-Accuracy VTEC Analysis in Ionospheric Research

The dynamic structure of the ionosphere and its changes play an important role in comprehending the natural cycle by linking earth sciences and space sciences. Ionosphere research includes a variety of fields like meteorology, radio wave reflection from the atmosphere, atmospheric anomaly detection, the impact on GNSS (Global Navigation Satellite Systems) signals, the exploration of earthquake precursors, and the formation of the northern lights. To gain further insight into this layer and to monitor variations in the total electron content (TEC), ionospheric maps are created using a variety of data sources, including satellite sensors, GNSS data, and ionosonde data. In these maps, data deficiencies are addressed by using interpolation methods. The objective of this study was to obtain high-accuracy VTEC (Vertical Total Electron Content) information to analyze TEC anomalies as precursors to earthquakes. We propose an innovative approach: employing alternative mathematical surfaces for VTEC calculations, leading to enhanced change analytical interpretation for anomaly detections. Within the scope of the application, the second-degree polynomial method, kriging (point and block model), the radial basis multiquadric, and the thin plate spline (TPS) methods were implemented as interpolation methods. During a 49-day period, the TEC values were computed at three different IGS stations, generating 1176 hourly grids for each interpolation model. As reference data, the ionospheric maps produced by the CODE (Center for Orbit Determination in Europe) Analysis Center were used. This study’s findings showed that, based on statistical values, the TPS model offered more accurate results than other methods. Additionally, it has been observed that the peak values in TEC calculations based on polynomial surfaces are eliminated in TPSs.

Spatial Dynamic Interaction Effects and Formation Mechanisms of Air Pollution in the Central Plains Urban Agglomeration in China

Accurately identifying the dynamic interaction effects and network structure characteristics of air pollution is essential for effective collaborative governance. This study investigates the spatial dynamic interactions of air pollution among 30 cities in the Central Plains Urban Agglomeration using convergent cross mapping. Social network analysis is applied to assess the overall and node characteristics of the spatial interaction network, while key driving factors are analyzed using an exponential random graph model. The findings reveal that air pollution levels in the Central Plains Urban Agglomeration initially increase before they decrease, with heavily polluted cities transitioning from centralized to sporadic distribution. Among the interactions, Heze’s air pollution impact on Kaifeng was the strongest, while Xinxiang’s impact on Changzhi was the weakest. The emission and receiving effects peaked during 2010–2012. The air pollution interactions among cities exhibit significant network characteristics, with block model results indicating that emitting and receiving relationships are primarily concentrated in the bidirectional spillover plate. Natural factors such as temperature and precipitation significantly influence the spatial interaction network. Economic and social factors like economic level and industrial sector proportion also have a significant impact. However, population density does not influence the spatial interaction network. This study contributes to understanding the spatial network of air pollution, thereby enhancing strategies for optimizing regional collaborative governance efforts to address air pollution.

Creating the conditions for student success through curriculum reform: the impact of an active learning, immersive block model

Creating the conditions for student success through curriculum reform: the impact of an active learning, immersive block model

Community detection in multiplex continous weighted nodes networks using an extension of the stochastic block model

Community detection in multiplex continous weighted nodes networks using an extension of the stochastic block model

Modeling spatial variability of mechanical parameters of layered rock masses and its application in slope optimization at the open-pit mine

Mining engineering with layered structures often obtains extensive geological data to ensure reliability of mining operations. Effectively utilizing these data to characterize the spatial distribution of mechanical parameters in layered rock mass is crucial for slope stability analysis. This study focuses on the Heishan open-pit mine as a case study, leveraging the distinctive characteristics of mining engineering geological data. A three-dimensional fracture network was then generated based on the distribution of fractures in the rocks, and the representative elementary volume of the rock mass was determined by calculating the volumetric joint count (Jv). Statistical characteristics of various geological data are analyzed, and a geological statistical method combining the Kriging method and inverse distance power method is applied to establish a spatial distribution block model for geological strength index (GSI) and rock mechanical properties. Subsequently, a spatial variability model of the mechanical parameters of the layered rock mass was generated based on the Hoek–Brown criterion. Furthermore, the heterogeneous mechanical model is implemented in numerical software for stability analysis and slope angle optimization. The findings indicate that each engineering zone of layered slopes exhibits unique mechanical parameters while demonstrating significant layered distribution patterns at a macro level. Considering spatial variability, the mechanical model significantly impacts slope stability and slope angle optimization outcomes. Our research methodology facilitates accurate quantification of the heterogeneity of mechanical parameters in layered slopes without incurring excessive additional survey costs, enabling more rational explanations of slope landslides and the provision of suitable slope angle optimization designs.

Grade control drillhole spacing and mining selectivity determination using high resolution simulations applied on distinctly heterogeneous open pit mines

The grade control drillhole spacing and mining selectivity decisions are typically made using the resource model estimated from exploration and infill drilling data. Once production starts, large quantities of grade control data are collected to delineate ore and waste boundaries for ore control. In this work, a grade control drillhole spacing and mining selectivity optimization workflow is presented which allows the practitioner to use site specific knowledge to determine the most profitable ore control mining scenario. The densely gridded production data is used to simulate a ground truth block model from which scenarios of variable drillhole spacing and selectivity are evaluated against their corresponding costs to determine the maximum profit scenario. Eleven mining scenarios are evaluated using year production data from three distinctly heterogeneous mine with drillhole spacing and mining selectivity varying from 3 × 3 × 3 m (27 m3) to 30 × 30 × 15 m (13,500 m3). The profit differences from the optimum scenario varied by millions of dollars (1–8%) against the next best case depending on the heterogeneity of the deposit. Practitioners could apply this workflow to inform grade control drillhole spacing and mining selectivity decisions for different domains within the mine or multiple pits especially if distinctly heterogeneous volumes exist.

Research and application discussion of cranial bone model preparation method based on three-dimensional reconstruction and 3D printing technology.

The aim of this study was to find an alternative method to meet traditional human anatomy teaching and clinical needs in order to solve the problem of cranial specimen attrition and specimen resource shortage due to long-term use. We performed a computed tomography (CT) scan of a well-preserved male cranial specimen and used Mimics 19.0 software for 3D reconstruction and cranial block separation. Subsequently, we compared the recognition ability of the processed cranial digital model with that of the 3D body digital model and used 3D printing to create the cranial model and compare it with the physical specimen. Twenty-two cranial bone block models were obtained, excluding the hyoid bone. Their 3D reconstructed digital models had better bony landmark recognition than the 3D body human digital models, and the differences between the 3D printed models and the physical specimens were minimal. In addition, only one stereolithography (STL) file was required to produce the cranial models, which facilitates repetitive printing at any time. By isolating cranial bone blocks through 3D reconstruction techniques and preparing high-quality cranial models in combination with 3D printing techniques, this study solves the problem of shortage of cranial teaching specimens for the sustainable development of clinical and medical schools.

Fabrication and characterization of ceramic tubular composite membranes using slag waste materials for oily wastewater treatment

In this study, low-cost tubular ceramic membranes were fabricated by using waste slag and natural raw materials in order to decrease the manufacturing carbon footprints. The effects of incorporation of phosphorus slag (PS) and blast furnace slag (BFS) in the mullite-zeolite membrane body were investigated. The structural characteristics of the fabricated membranes were evaluated using X-ray diffraction (XRD), field emission–scanning electron microscopy (FESEM), atomic force microscopy (AFM), contact angle, porosity and average pore size analyses. Thermal and mechanical stability were studied by thermogravimetric analysis (TGA) and three-point bending test, respectively. The oily wastewater treatment tests revealed that an increase in the slag percentage from 0 to 30% leads to enhancing the permeate flux from 99 l m−2 h−1 to 349 l m−2 h−1 for PS-based tubular membrane and to 244 l m−2 h−1 for BFS-based tubular membrane under 1 bar applied. The chemical oxygen demand (COD) removal percentage of all membranes was reported almost 99% for oily wastewater feed with a COD concentration of 612 mg l−1. In addition, the investigation of membrane fouling mechanisms was carried out using Hermia models indicating that the best correlation with the experimental data is observed for the complete pore blocking model. This study presents experimental foundations aimed at enhancing the performance of affordable slag-based membranes, thus fostering their applicability in engineering contexts.

Nonlinear static analysis of masonry structures with mortar joints and cracking units by optimization‐based rigid block models

AbstractA rigid block model with elasto‐plastic softening interfaces is developed for nonlinear static analysis of masonry structures subject to monotonic loading. Cracking, crushing, and shear failures are taken into account at interfaces, following a simple micro‐modeling approach. An optimization‐based formulation is used for the solution of the equation systems governing the behavior of the rigid block assemblage. A simple incremental solution procedure is implemented to take into account the material softening behavior and the effects of large displacements on equilibrium conditions. The interface models are validated against tension and shear tests on bi‐block prisms from the literature. Applications to numerical and experimental out‐of‐plane loaded masonry walls as well as to circular arches with mortar joints are presented to evaluate the effects of tensile strength and the accuracy of the developed model against responses involving P‐Δ effects. Comparisons with experimental tests on shear walls also involving cracking of the units in the failure mechanisms are finally reported to discuss the potentialities and limitations of the proposed modeling approach.

Network structure, dynamic evolution and block characteristics of sovereign debt risk: The global evidence

Global sovereign debt risks are escalating with the tightening of global liquidity. We apply the LASSO-VAR spillover model, network approach and block model to analyze the overall situation and time-varying characteristics of sovereign risk volatility spillover effects among 50 countries. The results show that there is a discernible cyclical pattern in the spillover effect of global sovereign risk volatility, with the spillover intensity progressively rising in each cycle, and more countries have emerged as "net risk exporters" recently. Countries and regions exhibit diverse risk spillover traits, and assume varying roles in the transmission of sovereign debt risks. The originator of a sovereign risk shock isn't necessarily its primary disseminator, underscoring the need to account for systemic significance and risk infectivity. The interlinkages among sovereign debt risk spillover blocks vary over time, given that the composition and attributes of these blocks change. Our findings provide implications for related regulators and investors.

A multi-symptomatic model of heroin use disorder in rats reveals distinct behavioral profiles and neuronal correlates of heroin vulnerability versus resiliency.

The behavioral and diagnostic heterogeneity within human opioid use disorder (OUD) diagnosis is not readily captured in current animal models, limiting translational relevance of the mechanistic research that is conducted in experimental animals. We hypothesize that a non-linear clustering of OUD-like behavioral traits will capture population heterogeneity and yield subpopulations of OUD vulnerable rats with distinct behavioral and neurocircuit profiles. Over 900 male and female heterogeneous stock rats, a line capturing genetic and behavioral heterogeneity present in humans, were assessed for several measures of heroin use and rewarded and non-rewarded seeking behaviors. Using a non-linear stochastic block model clustering analysis, rats were assigned to OUD vulnerable, intermediate and resilient clusters. Additional behavioral tests and circuit analyses using c-fos protein activation were conducted on the vulnerable and resilient subpopulations. OUD vulnerable rats exhibited greater heroin taking and seeking behaviors relative to those in the intermediate and resilient clusters. Akin to human OUD diagnosis, further vulnerable rat sub-clustering revealed subpopulations with different combinations of behavioral traits, including sex differences. Lastly, heroin cue-induced neuronal patterns of circuit activation differed between resilient and vulnerable phenotypes. Behavioral sex differences were recapitulated in patterns of circuitry activation, including males preferentially engaging extended amygdala stress circuitry, and females cortico-striatal drug cue-seeking circuitry. Using a non-linear clustering approach in rats, we captured behavioral diagnostic heterogeneity reflective of human OUD diagnosis. OUD vulnerability and resiliency were associated with distinct neuronal activation patterns, posing this approach as a translational tool in assessing neurobiological mechanisms underpinning OUD.

Fractal evolution characteristics of fracture meso-damage in uniaxial compression rock masses using bonded block model

With regard to deep mining in metal mines, an investigation into the failure mode of deep fractured rock masses and their corresponding acoustic emission signal characteristics is conducted via uniaxial compression tests. Subsequently, a fractal damage renormalization group mechanical model is developed to explain the behavior of those fractured rock masses. Employing the bonded block model (BBM) numerical simulation method, fracture process in synthetic rock samples is analyzed, thereby validating the efficacy of the mechanical model. The numerical simulations highlight the critical role of fractures expansion in underlying the deterioration of rock mass strength. As the peak load decreases, the fracture fractal dimension increases, leading to a significant 14.2% reduction in compressive strength accompanied by an approximate 8.7% rise in average fracture fractal dimension. A comparative analysis of tetrahedral and voronoi block synthetic rock samples reveals the tetrahedral block samples exhibit a superior ability to depict the fracture behavior of fractured rock masses. Specifically, they offer a more accurate simulation of acoustic emission characteristics and failure modes. Furthermore, variations in the fracture fractal dimension with respect to the hole defect’s position are observed, with the maximum value occurring along the vertical axis of the hole defect. This observation underscores the potential utility of visually monitoring deep rock fracture dynamics as an effective mean for quantitatively evaluating fracture damage and strength degradation in deep rock formations.

Abstract Or118: Transcription Factor Gene Therapy for Treatment of Junctional Bradycardia in a Porcine Model of Complete Atrioventricular Block Following His Bundle Ablation

Background: Pacemaker implantation is standard treatment for patients with complete atrioventricular (AV) block. However, contraindications for device implantations create a need for alternative non-hardware cardiac pacing solutions. We developed a porcine model of complete heart block with junctional bradycardia to test a novel transcription factor-based gene therapy consisting of Tbx18, Shox2 and Tbx3 (TST). Somatic reprogramming of ventricular cardiomyocytes by TST induces pacemaker-like activity and provides biological pacing in vitro . Methods: Eight domestic swine (Yorkshire/Landrace) received catheter ablation of the AV node/His Bundle resulting in complete AV block, confirmed by dissociation of P and R waves on ECG. An implanted device pacemaker (VVI mode) maintained cardiac output during occurrences of junctional bradycardia below 50 bpm. Telemetric 3-lead ECG was recorded continuously. Subjects received TST gene therapy or control gene (GFP) via catheter-based intramuscular injection into the high right ventricular septum. Pacemaker usage and ECG were continuously monitored for 8 weeks. Results: Following AV node ablation, junctional escape rhythm decelerated into junctional bradycardia. After 3 weeks of AV block, 49.9 ± 13.1% of heartbeats were initiated by the device pacemaker. Upon reaching pacemaker dependence of 95% in an average of 27.9 ± 5.5 days, subjects received TST gene therapy or control injection. In subjects receiving TST therapy, daily pacemaker reliance decreased to 50% dependency in an average of 14.7 ± 2.3 days, while in GFP controls, daily pacemaker dependency at 50 bpm remained unchanged at >98% throughout follow-up. In TST-treated subjects, reductions in pacemaker dependence were associated with increases in ventricular rates exceeding 70 bpm. Efficacy of gene therapy waned after about one month; an improvement of >10% pacemaker dependency over two consecutive days was still observed on average 29.0 ± 4.1 days after TST injection. Conclusion: In a porcine model of complete AV block, ventricular junctional escape rhythm decelerated into bradycardia in less than one month. Subsequent gene therapy by TST injection into the high ventricular septum alleviated pacemaker dependency and enhanced heart rate for 29.0 ± 4.1 days. Somatic reprogramming of cardiomyocytes by TST gene delivery may provide a biological pacemaker alternative to hardware device implantation for therapeutic cardiac pacing.

Does (dis)agreement reflect beliefs? An analysis of advocacy coalitions in Swiss pesticide policy

AbstractAgricultural pesticide use is a wicked sustainability challenge: Trade‐offs exist between health, environmental, agro‐economic, and socio‐political objectives. Various actors involved have diverse beliefs regarding these trade‐offs and policies to address the challenge. But to what extent does the agreement or disagreement between actors reflect belief similarities or differences, and thus, the formation of advocacy coalitions? To answer this question, the study draws on the advocacy coalition framework and investigates data from 54 key actors in the case of Swiss pesticide policy. The study explores the relationship between the actors' (dis)agreement relations and their beliefs using Random Forests. Coalitions are identified through block modeling and beliefs based on multi‐attribute value theory. The study shows that the two relations are a good proxy for identifying coalitions with conflict lines concerning beliefs and presents an approach to exploring ideological reasons behind (dis)agreement relations that supports identifying conflicting beliefs relevant to future policy solutions.

Research on the Twin-Link Stepping Temporary Support Mechanism and the Repeatable Supportability of the Roof in the Underground Excavation Roadway of Coal Mine

The coal mine’s underground heading roadway suffers from a lack of effective temporary support, which contributes to low efficiency and inadequate safety in excavation operations. This paper presents a novel approach for roadway excavation, support, and anchoring, utilizing the twin-link stepping temporary support method. To address the stability requirements of the roadway roof in this support method, a numerical model of the excavation face was developed using the BBM (Bonded Block Model) method in 3DEC 7.0 software. Through numerical simulation, the repeatability of the twin-link stepping temporary support process was assessed for various roadway roof rock types, thicknesses, and burial depths. By considering aspects such as roof fragmentation, roof convergence, and relative displacement between the direct roof and the bedrock, the range of roadway roof repeatability was determined. The proposed twin-link stepping temporary support process, along with its applicable roof conditions, establishes a theoretical foundation for implementing the parallel operation mode in coal mine underground heading roadways, thereby significantly enhancing safety and efficiency.

Effects of drilling parameters on stress relief performance during mining

Abstract This study investigated the effects of borehole diameter and borehole interval on the stress relief performance of coal seams during mining. A discrete element numerical model was established based on the Voronoi and block models, and the stress relief performance was investigated in terms of axial stress, vertical displacement, and plastic zone development using the control variates method. The results showed that a decrease in the distance from the workface was accompanied by an increase in the effects of mining, the stress concentration, and the vertical displacement of the roof. Coal mining had positive effects on fracture propagation in front of the workface. As the borehole interval increased, the density of boreholes in the coal seams decreased, reducing the stress concentration and fracture propagation in front of the workface. The stress relief performance of the boreholes in the coal seams was improved at an borehole interval of 8 m. However, as the borehole diameter increased, the stress concentration near the boreholes decreased, reducing the effects of the workface mining on stress relief through the boreholes. Meanwhile, increasing the borehole diameter decreased the vertical displacement of the roof but exacerbated fracture propagation in front of the workface, which improved the stress relief performance of the boreholes in the coal seams. This study provides a reference for arranging boreholes in coal seams during mining.

MicroRNA-301a knockout attenuates peripheral nerve regeneration by delaying Wallerian degeneration.

Our recent study demonstrated that knockout of microRNA-301a attenuates migration and phagocytosis in macrophages. Considering that macrophages and Schwann cells synergistically clear the debris of degraded axons and myelin during Wallerian degeneration, which is a prerequisite for nerve regeneration, we hypothesized that microRNA-301a regulates Wallerian degeneration and nerve regeneration via impacts on Schwann cell migration and phagocytosis. Herein, we found low expression of microRNA-301a in intact sciatic nerves, with no impact of the microRNA-301a knockout on nerve structure and function. By contrast, we found significant upregulation of microRNA- 301a in injured sciatic nerves. We established a sciatic nerve crush model in microRNA-301a knockout mice, which exhibited attenuated morphological and functional regeneration following sciatic nerve crush injury. The microRNA-301a knockout also led to significantly inhibited Wallerian degeneration in an in vivo sciatic nerve-transection model and in an in vitro nerve explant block model. Schwann cells with the microRNA-301a knockout showed inhibition of phagocytosis and migration, which was reversible under transfection with microRNA-301a mimics. Rescue experiments involving transfection of microRNA-301a-knockout Schwann cells with microRNA-301a mimics or treatment with the C-X-C motif receptor 4 inhibitor WZ811 indicated the mechanistic involvement of the Yin Yang 1/C-X-C motif receptor 4 pathway in the role of microRNA-301a. Combined with our previous findings in macrophages, we conclude that microRNA-301a plays a key role in peripheral nerve injury and repair by regulating the migratory and phagocytic capabilities of Schwann cells and macrophages via the Yin Yang 1/C-X-C motif receptor 4 pathway.

The use of block modeling to predict the variability of the bulk weight of titanomagnetite ore

The article presents the results of the performed studies using block modeling technologies to determine the volume weight of the titanium magnetite ore of the Northern deposit of the Gusevogorsky deposit, developed by EVRAZ KGOK OJSC. The methods used for laboratory studies of samples of titanium magnetite ore from exploration wells are described. The results of statistical processing of the obtained data are presented. The relationship between the bulk weight of the ore and the iron content in it has been established. Based on block modeling of the massif, a forecast was made for the deep horizons of the Northern Quarry of JSC EVRAZ KGOK on changes in the volume weight of ore and the total iron content in it, which will allow the company's specialists to use the obtained data in geological and technological calculations.