scholarly journals Cylindrical Caved Space Stability Analysis for Extension Prediction of Mining-Induced Surface Subsidence

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yang Liu ◽  
Yongxiang Ge ◽  
Congrui Zhang ◽  
Fengyu Ren ◽  
Junsheng Ma ◽  
...  
Keyword(s):  
Large Scale ◽  
Shear Failure ◽  
Surface Subsidence ◽  
Geological Hazards ◽  
Proposed Model ◽  
Iron Mine ◽  
Waste Rocks ◽  
Surface Destruction ◽  
Circular Surface ◽  
The Impact

Subsequent extension of surface subsidence after vertical caving leads to large-scale surface destruction, as well as associated geological hazards. The extension prediction for cylindrical caved space, which appears circular surface subsidence, is still an intractable issue, due to the absence of robust models. To fill such a research gap, this paper provides an analytical model for the depth and orientation where the shear failure of isotropic rocks around the caved space is firstly observed. The anisotropy of surrounding rocks is further involved to enable this model to analyze the slip failure along discontinuities in anisotropic stress state. The prediction for the extension of the surface subsidence in Xiaowanggou iron mine is conducted, and the comparison between the prediction and the observation in satellite images demonstrates the validity of the proposed model. Even though this model cannot provide a definite boundary after extension, the prediction for the orientation surface subsidence extends to contribute to mitigating the effect of geological hazards. Another contribution of this work is to provide guidance to mitigate the impact of surface subsidence on safety and environment, such as filling the interspace between large-sized caved rocks by dumping small-sized waste rocks or backfilling the caved space with waste rocks.

scholarly journals Prediction of Surface Subsidence Extension due to Underground Caving: A Case Study of Hemushan Iron Mine in China

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Hangxing Ding ◽  
Song Chen ◽  
Shuai Chang ◽  
Guanghui Li ◽  
Lei Zhou
Keyword(s):  
Rock Mass ◽  
Analytical Model ◽  
Construction Projects ◽  
Large Scale ◽  
Surrounding Rock ◽  
Surface Subsidence ◽  
Proposed Model ◽  
Iron Mine ◽  
Subsidence Zone ◽  
The Stability

Underground caving can potentially lead to large-scale surface destruction. To test the safety conditions of the surface construction projects near the circular surface subsidence zone in the Hemushan Iron Mine, this paper proposes an analytical model to analyze the stability of the cylindrical caved space by employing the long-term strength of the surrounding rock mass, the in situ stress, and the impact of caved materials as inputs. The proposed model is valid for predicting the orientation and depth where rock failure occurs and for calculating the maximum depth of the undercut, above which the surrounding rock mass of the caved space can remain stable for a long duration of time. The prediction for the Hemushan Iron Mine from the proposed model reveals that the construction projects can maintain safe working conditions, and such prediction is also demonstrated by the records from Google Earth satellite images. This means that the proposed model is valid for conducting such analysis. Additionally, to prevent rock failure above the free surface of caved materials, backfilling the subsidence zone with waste rocks is suggested, and such a measure is implemented in the Hemushan Iron Mine. The monitoring results show that this measure contributes to protecting the surrounding wall of the caved space from large-scale slip failure. The contribution of this work not only provides a robust analytical model for predicting the stability of rock around a cylindrical caved space but also introduces employable measures for mitigating the subsequent extension of surface subsidence after vertical caving.

scholarly journals A Security Assessment Model for Electrical Power Grid SCADA System

2019 ◽  
Vol 8 (12S2) ◽  
pp. 763-773
Keyword(s):  
Vulnerability Assessment ◽  
Cyber Security ◽  
Large Scale ◽  
Critical Infrastructure ◽  
Security Analysis ◽  
Assessment Model ◽  
Primary Concern ◽  
Scada System ◽  
Proposed Model ◽  
The Impact

Due to the wide application of SCADA systems in national critical infrastructure, their cyber security issues and vulnerabilities have been a primary concern; whereas, the impact and consequences of cyber-attacks to these systems have the potential to result in catastrophic consequences in the physical domain. Therefore, estimating possible attack impacts and identifying system vulnerabilities are major concern in SCADA management and operations. However, it is quite difficult to plan, execute and review vulnerability analysis in critical infrastructure systems as well as in industrial control systems (such as SCADA system) due to its complexity, large-scale and heterogeneity. Consequently, a consistent domain-specific conceptual model is required to establish a generic framework for cyber security analysis to examine and investigate security threats on cyber-physical systems, the role of the entities within the system as well as system operations. The main contribution of this work is to present a multi-facets model to support cyber security analysis practices such as penetration testing, vulnerability assessment and risk analysis. The proposed model presents a common insight among different SCADA configurations, implementations and the employed protocols to handle its complexity, heterogeneous and scale. To demonstrate the usability as a proof of concept and applicability of the proposed model, the paper also presents an example illustrating how the proposed model can be employed to carry out security vulnerability assessment.

scholarly journals Modeling the α-max capacity of transportation networks: a single-level mathematical programming formulation

2021 ◽  
Author(s):  
Zhaoqi Zang ◽  
Xiangdong Xu ◽  
Anthony Chen ◽  
Chao Yang
Keyword(s):  
Mathematical Programming ◽  
Travel Time ◽  
Large Scale ◽  
Transportation Network ◽  
Network Capacity ◽  
Solution Algorithm ◽  
Single Level ◽  
Capacity Model ◽  
Proposed Model ◽  
The Impact

AbstractNetwork capacity, defined as the largest sum of origin–destination (O–D) flows that can be accommodated by the network based on link performance function and traffic equilibrium assignment, is a critical indicator of network-wide performance assessment in transportation planning and management. The typical modeling rationale of estimating network capacity is to formulate it as a mathematical programming (MP), and there are two main approaches: single-level MP formulation and bi-level programming (BLP) formulation. Although single-level MP is readily solvable, it treats the transportation network as a physical network without considering level of service (LOS). Albeit BLP explicitly models the capacity and link LOS, solving BLP in large-scale networks is challenging due to its non-convexity. Moreover, the inconsideration of trip LOS makes the existing models difficult to differentiate network capacity under various traffic states and to capture the impact of emerging trip-oriented technologies. Therefore, this paper proposes the α-max capacity model to estimate the maximum network capacity under trip or O–D LOS requirement α. The proposed model improves the existing models on three aspects: (a) it considers trip LOS, which can flexibly estimate the network capacity ranging from zero to the physical capacity including reserve, practical and ultimate capacities; (b) trip LOS can intuitively reflect users’ maximum acceptable O–D travel time or planners’ requirement of O–D travel time; and (c) it is a convex and tractable single-level MP. For practical use, we develop a modified gradient projection solution algorithm with soft constraint technique, and provide methods to obtain discrete trip LOS and network capacity under representative traffic states. Numerical examples are presented to demonstrate the features of the proposed model as well as the solution algorithm.

scholarly journals Research on the Interaction Mechanism between Landslide and Tunnel Engineering

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yufang Zhang ◽  
Jian Li ◽  
Hongyu Liu ◽  
Wei Li ◽  
Jiaming Li ◽  
...  
Keyword(s):  
Large Scale ◽  
Shear Failure ◽  
Concrete Strength ◽  
Interaction Mechanism ◽  
Tunnel Structure ◽  
Tunnel Engineering ◽  
Railway Tunnel ◽  
Maximum Deformation ◽  
Limit Value ◽  
The Impact

The landslide at the entrance of a railway tunnel is large scale, and serious diseases are prone to appear under natural disasters, which threaten the safety of the tunnel. According to its characteristics, on-site long-term monitoring experiments and numerical analysis were carried out, and the mechanism of interaction between landslide and tunnel engineering was analyzed. The results show that under the impact of rainfall and earthquake, the original internal stress balance in the landslide body is disturbed, leading to the increase in landslide thrust and damage of the tunnel lining. Simultaneously, the excavation of the tunnel can slack the surrounding rock to increase the landslide thrust and make the landslide be finally formed; this landslide conversely acts on the tunnel, resulting in deformation and destruction of the tunnel. During the monitoring, under the influence of rainfall and earthquake, the stress of the secondary lining was continuously increased by 25%. Tunnel construction caused a maximum deformation of 30 mm in the antislide pile at a distance of 2.12 m, and the slope and the tunnel were also affected. Under extreme conditions such as rainfall and earthquake, shear failure occurred at the vault, bottom, and waist of the right-line tunnel located at the junction of soil and rock; at this time, the tensile strength of the tunnel reached 93.8% of the limit value of concrete, which seriously affected the safety of the tunnel. As for the weakened tunnel structure, measures such as dense planting and strengthening of concrete strength should be adopted to enhance the safety of the tunnel structure.

scholarly journals Creating a mathematical model of the impact of radiation-hazardous objects on the environment during a fire.

2021 ◽  
Vol 4 ◽  
pp. 99-111
Author(s):  
V.V. Derengovsky ◽  
◽  
O.A. Kaftanatina ◽  
P.L. Kordiukov ◽  
V.A. Menshenin ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Large Scale ◽  
Radiation Condition ◽  
Automated System ◽  
Exclusion Zone ◽  
Wind Rose ◽  
Cooling Reservoir ◽  
Proposed Model ◽  
The Impact ◽  
Simplified Mathematical Model

On the basis of the new data on the assessment of the removal from fires from stocks in the combustible material and the speed of weak grassroots fires spread, the wind rose in the Chernobyl Exclusion Zone and the capabilities of the HotSpot software package, there has been developed a mathematical model of real-time assessment of the consequences of accidents that may occur in the areas of radiation-hazardous objects during fires. The proposed model was verified on the basis of comparison with the data obtained during a large-scale fire in the Chernobyl Exclusion Zone in April 2020, and the maps of the Chernobyl Exclusion Zone’s air and soil contamination with 137Cs and 90Sr were made. Using the proposed mathematical model, there has been carried out the analysis of the degree of danger that may create radiation-hazardous objects in case of fire directly on the territory of their location. In the paper, there are also considered the examples of the sanitation point (SP) «Rudnia-Veresnia», SP «Rozsokha» and the «Point of vehicle washing near the ChNPP cooling reservoir» in comparison with the current contamination of air and soil around these facilities with radionuclides. The results of the conducted analysis have been used to make a conclusion about the insignificant impact on the environment of the Chernobyl Exclusion Zone compared to the current level of air pollution and the surface of its territory. Estimates of radiation exposure from SP «Rudnia-Veresnia», SP «Rozsokha» and the «Point of vehicle washing near the ChNPP cooling reservoir» to the environment have been obtained with the help of a simplified mathematical model. These data have a significant correlation with the actual data obtained in April 2020 (during a large-scale fire in the Chernobyl Exclusion Zone) in the areas of location of the points of the automated system of radiation condition control, and places of work, temporary and permanent stay of the personnel and the population. Therefore, the created simplified mathematical model can also be used to assess the radiation impact on the environment in the implementation of emergencies of various kinds at other numerous radiation-hazardous facilities of the ChEZ.

scholarly journals A COVID-19 model with a nonlinear incidence rate and intervention exit strategies for Kenya

2021 ◽  
Author(s):  
Rachel Waema Mbogo ◽  
Farai Nyabadza
Keyword(s):  
Large Scale ◽  
Model Parameters ◽  
Clear Understanding ◽  
Nonlinear Incidence ◽  
Intervention Measures ◽  
Proposed Model ◽  
Rapid Spread ◽  
Nonlinear Incidence Function ◽  
Individual Self ◽  
The Impact

Abstract The coronavirus disease (COVID-19) is a novel infection caused by SARS-CoV-2, a corona virus type that has previously not been seen in humans. The speedy spread of COVID-19 globally has greatly affected the socio-economic environments and health systems. To effectively address this rapid spread, it is imperative to have a clear understanding of the COVID-19 transmission dynamics. In this study we evaluate a COVID-19 epidemic model with a nonlinear incidence function and a saturating. We propose an SLIHRD data driven COVID 19 model which incorporates individual self initiated behavior change of the susceptible individuals. The proposed model allows the evaluation of the impact of easing intervention measures at specific times. To estimate the model parameters, the model was fitted to the daily reported COVID-19 cases in Kenya. Self initiated behavioral responses by individuals and large scale persistent testing proved to be the most effective measures to flatten the epidemic infection curve.The model illustrates the effect of mass testing on COVID-19 as well as individual self initiated behavioral change when the number of infected individuals increases. The results have significant impact on the management of COVID-19 and implementation of prevention policies.

Impact of COVID-19 on Nuclear Medicine in Germany, Austria and Switzerland: An International Survey in April 2020

2020 ◽  
Vol 59 (04) ◽  
pp. 294-299 ◽  
Author(s):  
Lutz S. Freudenberg ◽  
Ulf Dittmer ◽  
Ken Herrmann
Keyword(s):  
Nuclear Medicine ◽  
Health Systems ◽  
Personal Protective Equipment ◽  
Large Scale ◽  
Diagnostic Procedures ◽  
Protective Equipment ◽  
Current Crisis ◽  
Web Based ◽  
Public Versus Private ◽  
The Impact

Abstract Introduction Preparations of health systems to accommodate large number of severely ill COVID-19 patients in March/April 2020 has a significant impact on nuclear medicine departments. Materials and Methods A web-based questionnaire was designed to differentiate the impact of the pandemic on inpatient and outpatient nuclear medicine operations and on public versus private health systems, respectively. Questions were addressing the following issues: impact on nuclear medicine diagnostics and therapy, use of recommendations, personal protective equipment, and organizational adaptations. The survey was available for 6 days and closed on April 20, 2020. Results 113 complete responses were recorded. Nearly all participants (97 %) report a decline of nuclear medicine diagnostic procedures. The mean reduction in the last three weeks for PET/CT, scintigraphies of bone, myocardium, lung thyroid, sentinel lymph-node are –14.4 %, –47.2 %, –47.5 %, –40.7 %, –58.4 %, and –25.2 % respectively. Furthermore, 76 % of the participants report a reduction in therapies especially for benign thyroid disease (-41.8 %) and radiosynoviorthesis (–53.8 %) while tumor therapies remained mainly stable. 48 % of the participants report a shortage of personal protective equipment. Conclusions Nuclear medicine services are notably reduced 3 weeks after the SARS-CoV-2 pandemic reached Germany, Austria and Switzerland on a large scale. We must be aware that the current crisis will also have a significant economic impact on the healthcare system. As the survey cannot adapt to daily dynamic changes in priorities, it serves as a first snapshot requiring follow-up studies and comparisons with other countries and regions.

HOME VISITS DURING THE FIRST MONTH OF DELIVERY FOR RECENTLY DELIVERED WOMEN IN UTTAR PRADESH, INDIA

2020 ◽  
Vol 6 (5) ◽  
pp. 1183-1189
Author(s):  
Dr. Tridibesh Tripathy ◽  
Dr. Umakant Prusty ◽  
Dr. Chintamani Nayak ◽  
Dr. Rakesh Dwivedi ◽  
Dr. Mohini Gautam
Keyword(s):  
Large Scale ◽  
National Level ◽  
Uttar Pradesh ◽  
Life Time ◽  
Structured Interview ◽  
The Other ◽  
Registration System ◽  
Action Group ◽  
Current Article ◽  
The Impact

The current article of Uttar Pradesh (UP) is about the ASHAs who are the daughters-in-law of a family that resides in the same community that they serve as the grassroots health worker since 2005 when the NRHM was introduced in the Empowered Action Group (EAG) states. UP is one such Empowered Action Group (EAG) state. The current study explores the actual responses of Recently Delivered Women (RDW) on their visits during the first month of their recent delivery. From the catchment area of each of the 250 ASHAs, two RDWs were selected who had a child in the age group of 3 to 6 months during the survey. The response profiles of the RDWs on the post- delivery first month visits are dwelled upon to evolve a picture representing the entire state of UP. The relevance of the study assumes significance as detailed data on the modalities of postnatal visits are available but not exclusively for the first month period of their recent delivery. The details of the post-delivery first month period related visits are not available even in large scale surveys like National Family Health Survey 4 done in 2015-16. The current study gives an insight in to these visits with a five-point approach i.e. type of personnel doing the visit, frequency of the visits, visits done in a particular week from among those four weeks separately for the three visits separately. The current study is basically regarding the summary of this Penta approach for the post- delivery one-month period.     The first month period after each delivery deals with 70% of the time of the postnatal period & the entire neonatal period. Therefore, it does impact the Maternal Mortality Rate & Ratio (MMR) & the Neonatal Mortality Rates (NMR) in India and especially in UP through the unsafe Maternal & Neonatal practices in the first month period after delivery. The current MM Rate of UP is 20.1 & MM Ratio is 216 whereas the MM ratio is 122 in India (SRS, 2019). The Sample Registration System (SRS) report also mentions that the Life Time Risk (LTR) of a woman in pregnancy is 0.7% which is the highest in the nation (SRS, 2019). This means it is very risky to give birth in UP in comparison to other regions in the country (SRS, 2019). This risk is at the peak in the first month period after each delivery. Similarly, the current NMR in India is 23 per 1000 livebirths (UNIGME,2018). As NMR data is not available separately for states, the national level data also hold good for the states and that’s how for the state of UP as well. These mortalities are the impact indicators and such indicators can be reduced through long drawn processes that includes effective and timely visits to RDWs especially in the first month period after delivery. This would help in making their post-natal & neonatal stage safe. This is the area of post-delivery first month visit profile detailing that the current article helps in popping out in relation to the recent delivery of the respondents.   A total of four districts of Uttar Pradesh were selected purposively for the study and the data collection was conducted in the villages of the respective districts with the help of a pre-tested structured interview schedule with both close-ended and open-ended questions.  The current article deals with five close ended questions with options, two for the type of personnel & frequency while the other three are for each of the three visits in the first month after the recent delivery of respondents. In addition, in-depth interviews were also conducted amongst the RDWs and a total 500 respondents had participated in the study.   Among the districts related to this article, the results showed that ASHA was the type of personnel who did the majority of visits in all the four districts. On the other hand, 25-40% of RDWs in all the 4 districts replied that they did not receive any visit within the first month of their recent delivery. Regarding frequency, most of the RDWs in all the 4 districts received 1-2 times visits by ASHAs.   Regarding the first visit, it was found that the ASHAs of Barabanki and Gonda visited less percentage of RDWs in the first week after delivery. Similarly, the second visit revealed that about 1.2% RDWs in Banda district could not recall about the visit. Further on the second visit, the RDWs responded that most of them in 3 districts except Gonda district did receive the second postnatal visit in 7-15 days after their recent delivery. Less than half of RDWs in Barabanki district & just more than half of RDWs in Gonda district received the third visit in 15-21 days period after delivery. For the same period, the majority of RDWs in the rest two districts responded that they had been entertained through a home visit.

The Impact of Quantitative Easing on Emerging Markets – Literature Review

e-Finanse ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 67-76
Author(s):  
Piotr Bartkiewicz
Keyword(s):  
Emerging Markets ◽  
Large Scale ◽  
Empirical Literature ◽  
Quantitative Easing ◽  
Methodological Choices ◽  
The Subject ◽  
Methodological Approaches ◽  
The Impact ◽  
Sufficient Precision

AbstractThe article presents the results of the review of the empirical literature regarding the impact of quantitative easing (QE) on emerging markets (EMs). The subject is of interest to policymakers and researchers due to the increasingly larger role of EMs in the world economy and the large-scale capital flows occurring after 2009. The review is conducted in a systematic manner and takes into consideration different methodological choices, samples and measurement issues. The paper puts the summarized results in the context of transmission channels identified in the literature. There are few distinct methodological approaches present in the literature. While there is a consensus regarding the direction of the impact of QE on EMs, its size and durability have not yet been assessed with sufficient precision. In addition, there are clear gaps in the empirical findings, not least related to relative underrepresentation of the CEE region (in particular, Poland).

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