scholarly journals Movement and Protection for Random Shape Rockfalls in Steeply Dipping Coal Seams

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Ming Liu ◽  
Jie Chen
Keyword(s):  
3D Model ◽  
Peak Stress ◽  
Time Interval ◽  
Random Shape ◽  
Coal Seams ◽  
Factors Affecting ◽  
Grid Model ◽  
Working Face ◽  
System Data ◽  
Geographic Information System Data

In view of the randomness of rockfalls shape and irregularity of the bottom floor of working face in steeply dipping coal seams (SDCS), it is difficult to accurately simulate rockfall movement, and it is consequently unable to effectively protect against multirockfalls. Therefore, a method for generating random shape rockfalls based on ellipsoid equation is proposed, and a 3D grid model of real bottom floor of working face is established based on the geographic information system data. In order to verify the accuracy and feasibility of the method and 3D model, the trajectory simulated by Rockyfor3D software is compared, and the proposed method and 3D model prove to be effective in simulating rockfall movement more accurately. Then the proposed method and 3D grid model are applied to solve the problem of multirockfalls protection in numerical simulation, and the main factors affecting the structural stress response of protective netting are analyzed by taking three incident modes of parallel heights, ladder parallel, and the same trajectory. In the simulation, it is found out that the trajectory of irregular rockfalls is greatly affected by the shape of rockfall and working face floor; during the process of multiple rockfalls colliding with the protective netting, the peak stress on the protective netting is inversely proportional to both the time interval between each rockfall and the distance between each rockfall. The findings presented in this research contribute to rockfall prediction and protection against rockfall hazards.

scholarly journals Study of Top Coal Partition and Key Delayed-Action Region for Horizontal Sublevel Top Coal Caving in Deeply Inclined Seam

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jia-fan Zhang ◽  
Xiaoyu Liu ◽  
Yang Liu ◽  
Xiao-ping Shao ◽  
Hui-mei Zhang
Keyword(s):  
Damage Zone ◽  
Tensile Failure ◽  
Type I ◽  
Coal Seams ◽  
Related Factors ◽  
Factors Affecting ◽  
Working Face ◽  
Sublevel Caving ◽  
Delayed Action ◽  
Arch Structure

Horizontal sublevel caving is the unique way to mine the steep and extra thick coal seams. We aim to determine reasonable height of horizontal subsection, which is crucial to ensure the output and safety of mining. For this aim, a theoretical model is established to determine the theoretical solution of elastic stress distribution in deeply inclined coal seam, and first principal stress expression is derived. And on this basis, related factors affecting the top coal caving property and key delayed-action areas are investigated. The results show that there are four zones in top coal, which are tensile failure zone (TFZ), tensile damage zone (TDZ), elastic zone (EZ), and compression-shear damage zone (CSDZ). The elevation of sublevel height cannot increase the release of top coal. It is necessary to determine the key region of affecting the top coal caving. The key delayed-action region (KDAR) consists of EZ and TFZ in top coal; the EZ and TFZ are type I and II KDAR, respectively, and type I is the key area of weakening top coal. In order to effectively weaken KDAR, opening coal channel of core region, and especially effectively obstructing the continuous moving upward of top coal caving arch structure with the help of weakening top coal body in type I KDAR, would promote caving property of top coal and improve the working face extraction rate.

scholarly journals Segment-Based Approach for Assessing Hazard Risk of Coastal Highways in Hawai‘i

2019 ◽  
Vol 2673 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Harrison Togia ◽  
Oceana P. Francis ◽  
Karl Kim ◽  
Guohui Zhang
Keyword(s):  
Qualitative Method ◽  
Data Sets ◽  
Regional Environment ◽  
The Road ◽  
Hazard Exposure ◽  
Multiple Indicators ◽  
System Data ◽  
Rural Highway ◽  
Geographic Information System Data

Hazards to roadways and travelers can be drastically different because hazards are largely dependent on the regional environment and climate. This paper describes the development of a qualitative method for assessing infrastructure importance and hazard exposure for rural highway segments in Hawai‘i under different conditions. Multiple indicators of roadway importance are considered, including traffic volume, population served, accessibility, connectivity, reliability, land use, and roadway connection to critical infrastructures, such as hospitals and police stations. The method of evaluating roadway hazards and importance can be tailored to fit different regional hazard scenarios. It assimilates data from diverse sources to estimate risks of disruption. A case study for Highway HI83 in Hawai‘i, which is exposed to multiple hazards, is conducted. Weakening of the road by coastal erosion, inundation from sea level rise, and rockfall hazards require adaptation solutions. By analyzing the risk of disruption to highway segments, adaptation approaches can be prioritized. Using readily available geographic information system data sets for the exposure and impacts of potential hazards, this method could be adapted not only for emergency management but also for planning, design, and engineering of resilient highways.

scholarly journals Comprehensive technical support for safe mining in ultra-close coal seams: A case study

2021 ◽  
pp. 014459872110093
Author(s):  
Wei Zhang ◽  
Jiawei Guo ◽  
Kaidi Xie ◽  
Jinming Wang ◽  
Liang Chen ◽  
...  
Keyword(s):  
Coal Seam ◽  
Technical Support ◽  
Surrounding Rock ◽  
Coal Seams ◽  
Deformation Control ◽  
Hard Roof ◽  
Working Face ◽  
Close Coal Seams ◽  
Safe Mining

In order to mine the coal seam under super-thick hard roof, improve the utilization rate of resources and prolong the remaining service life of the mine, a case study of the Gaozhuang Coal Mine in the Zaozhuang Mining Area has been performed in this paper. Based on the specific mining geological conditions of ultra-close coal seams (#3up and #3low coal seams), their joint systematic analysis has been performed, with the focus made in the following three aspects: (i) prevention of rock burst under super-thick hard roof, (ii) deformation control of surrounding rock of roadways in the lower coal seam, and (iii) fire prevention in the goaf of working face. Given the strong bursting tendency observed in upper coal seam and lower coal seam, the technology of preventing rock burst under super-thick hard roof was proposed, which involved setting of narrow section coal pillars to protect roadways and interleaving layout of working faces. The specific supporting scheme of surrounding rock of roadways in the #3low1101 working face was determined, and the grouting reinforcement method of local fractured zones through Marithan was further proposed, to ensure the deformation control of surrounding rock of roadways in lower coal seams. The proposed fire prevention technology envisaged goaf grouting and spraying to plug leaks, which reduced the hazard of spontaneous combustion of residual coals in mined ultra-close coal seams. The technical and economic improvements with a direct economic benefit of 5.55 million yuan were achieved by the application of the proposed comprehensive technical support. The research results obtained provide a theoretical guidance and technical support of safe mining strategies of close coal seams in other mining areas.

scholarly journals Financing Growth through Remittances and Foreign Direct Investment: Evidences from Balkan Countries

2021 ◽  
Vol 14 (3) ◽  
pp. 117
Author(s):  
Esmeralda Jushi ◽  
Eglantina Hysa ◽  
Arjona Cela ◽  
Mirela Panait ◽  
Marian Catalin Voica
Keyword(s):  
Developing Economies ◽  
Central Banks ◽  
Sustainable Growth ◽  
Time Interval ◽  
Foreign Direct Investments ◽  
Factors Affecting ◽  
Balkan Countries ◽  
To Come ◽  
Sustainable Economic Growth ◽  
The Impact

The ultimate goal of central banks, worldwide, is to promote the foundations for sustainable economic growth. In the case of developing economies, in particular, such objective requires time, huge efforts, attention, and plenty of resources in order to be accomplished to the fullest degree. This paper thoroughly investigates key factors affecting Balkan countries’ economic development (as measured by gross domestic product (GDP) growth), focusing especially on the impact of remittances. The analysis was done over an 18-year time interval (2000–2017) and builds on 144 observations. The data figures were retrieved from the World Bank database while two dummies were created to test the impact of the last financial crisis (2008–2012). Econometric tools were employed to carry out a broad analysis on the interdependencies that exist and, in particular, to determine the role of remittance income on growth. The vector auto regressive model was estimated using EViews software, and was used to come up with relevant insights. Empirical findings suggest the following: population growth, remittances, and labor force participation are insignificant factors for sustainable growth. On the other hand, previous levels of GDP, trade, and foreign direct investments (FDIs) appear to be relevant for the predictor. This research provides up-to-date conclusions, which can be considered during the decision-making process of central banks, as well as by government policymakers.

scholarly journals Computer-Assisted System in Stress Radiography for Anterior Cruciate Ligament Injury with Correspondent Evaluation of Relevant Diagnostic Factors

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 419
Author(s):  
Chien-Kuo Wang ◽  
Liang-Ching Lin ◽  
Yung-Nien Sun ◽  
Cheng-Shih Lai ◽  
Chia-Hui Chen ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Cruciate Ligament ◽  
Anterior Tibial Translation ◽  
Computer Assisted ◽  
Time Interval ◽  
Stress Radiography ◽  
Factors Affecting ◽  
Anterior Tibial ◽  
Anterior Cruciate ◽  
Tibial Translation

We sought to design a computer-assisted system measuring the anterior tibial translation in stress radiography, evaluate its diagnostic performance for an anterior cruciate ligament (ACL) tear, and assess factors affecting the diagnostic accuracy. Retrospective research for patients with both knee stress radiography and magnetic resonance imaging (MRI) at our institution was performed. A complete ACL rupture was confirmed on an MRI. The anterior tibial translations with four different methods were measured in 249 patients by the designed algorithm. The diagnostic accuracy of each method in patients with all successful measurements was evaluated. Univariate logistic regression analysis for factors affecting diagnostic accuracy of method four was performed. In the inclusive 249 patients, 177 patients (129 with completely torn ACLs) were available for analysis. Mean anterior tibial translations were significantly increased in the patients with a completely torn ACL by all four methods, with diagnostic accuracies ranging from 66.7% to 75.1%. The diagnostic accuracy of method four was negatively associated with the time interval between stress radiography and MRI as well as force-joint distance on stress view, and not significantly associated with age, gender, flexion angle, intercondylar distance, and force-joint angle. A computer-assisted system measuring the anterior tibial translation in stress radiography showed acceptable diagnostic performance of complete ACL injury. A shorter time interval between stress radiography and MRI as well as shorter force-joint distance were associated with higher diagnostic accuracy.

Automatic Identification of Roadway Horizontal Alignment Information Using Geographic Information System Data: CurvS Tool

2021 ◽  
pp. 036119812110363
Author(s):  
Bekir Bartin ◽  
Sami Demiroluk ◽  
Kaan Ozbay ◽  
Mojibulrahman Jami
Keyword(s):  
Information System ◽  
New Jersey ◽  
Geographic Information System ◽  
Geographic Information ◽  
Automatic Identification ◽  
Web Based ◽  
Horizontal Alignment ◽  
System Data ◽  
Overlap Ratio ◽  
Geographic Information System Data

This paper introduces CurvS, a web-based tool for researchers and analysts that automatically extracts, visualizes, and analyzes roadway horizontal alignment information using readily available geographic information system roadway centerline data. The functionalities of CurvS are presented along with a brief background on its methodology. The validation of its estimation results are presented using actual horizontal alignment data from two different roadway types: Route 83, a two-lane two-way rural roadway in New Jersey and I-80, a freeway segment in Nevada. Different metrics are used for validation. These are identification rates of curved and tangent sections, overlap ratio of curved and tangent sections between estimated and actual horizontal alignment data, and percent fit of curve radii. The validation results show that CurvS is able to identify all the curves on these two roadways, and the estimated section lengths are significantly close to the actual alignment data, especially for the I-80 freeway segment, where 90% of curved length and 94% of tangent section length are correctly matched. Even when curves have small central angles, such as the ones in Route 83, CurvS’s estimations covers 71% of curved length and 96% of tangent section length.

scholarly journals The anthochron as a building block of flower development

2016 ◽  
Vol 51 (8) ◽  
pp. 899-904
Author(s):  
Nereu Augusto Streck ◽  
Natalia Teixeira Schwab
Keyword(s):  
Building Block ◽  
Flower Development ◽  
Field Experiments ◽  
Linear Regression Analysis ◽  
Time Interval ◽  
Simple Linear Regression ◽  
Vegetative Development ◽  
Flower Opening ◽  
Factors Affecting ◽  
Opening Phase

Abstract: Plant vegetative development has been widely described using the phyllochron concept, but little effort has been made to describe flower development during the reproductive phase. The objective of this work was to present the anthochron, through a review of the literature, as a building block of flower development, mainly during the flower opening phase. The anthochron is the time interval needed for two subsequent flowers to achieve the same developmental stage, with units of time in days or in ºC day per flower. The concept of anthochron fulfills part of the lack of studies on flower development, since it is considered a building block of the flower opening process. The anthochron can be measured from field experiments or estimated by a simple linear regression analysis. So far, the anthochron has only been quantified in Gladiolus x grandiflorus Hort. Therefore, factors affecting the anthochron still need to be determined in order to pinpoint their effect on the flower opening rate.

Factors affecting the reliability of the McMaster technique

1986 ◽  
Vol 60 (4) ◽  
pp. 260-262 ◽  
Author(s):  
Alison Dunn ◽  
Anne Keymer
Keyword(s):  
Salt Solution ◽  
Time Interval ◽  
Dilution Ratio ◽  
Laboratory Procedure ◽  
Heligmosomoides Polygyrus ◽  
Factors Affecting ◽  
Faecal Material ◽  
Mcmaster Technique ◽  
Sample Dilution ◽  
Normal Laboratory

ABSTRACTFactors detraction from the reliability of faecal egg counts based on the McMaster technique include variation in flotation time (interval between loading chamber and counting eggs) and sample dilution (ratio of faecal material to salt solution). We recommend standardization of both these variables as normal laboratory procedure, and propose optima of a 30 minute flotation time and a sample dilution of 15 ml salt solution/ g faeces for use of the McMaster technique in the estimation of the fecundity of Heligmosomoides polygyrus (Nematoda).

scholarly journals RESULTS OF APPLYING THE METHODOLOGY FOR THE QUANTITATIVE ASSESSMENT CONFIRM THE PREDICTION OF THE 3D MODELFOR HORIZONTAL SECTION OF WELLS

2017 ◽  
pp. 13-19
Author(s):  
R. M. Bembel ◽  
I. A. Schetinin
Keyword(s):  
Quantitative Assessment ◽  
3D Model ◽  
Forecast Model ◽  
Horizontal Section ◽  
Factors Affecting

The article discusses results of the use methodology for quantification of prediction of the 3D model for geosteering. This methodology tested for 90 wells with horizontal completion. According to the obtained statistics to assess factors affecting the reliability of the forecast model and defines the boundary criteria of quality confirmation.

Sign in / Sign up

Export Citation Format

Share Document