scholarly journals Rockburst hazard assessment based on seismic tomography and analytical modelling - a case study

2018 ◽  
Vol 66 ◽  
pp. 01009
Author(s):  
Dariusz Chlebowski ◽  
Zbigniew Burtan

In accordance with the formal regulations currently in force in Poland, the criteria for rockburst hazard assessment with respect to coal deposits include the records of seismic events and their impacts, de-stressing of the entire seam or its parts and expert opinions of mine operation engineers. Effectiveness of the de-stressing can be verified by geophysical test data whilst the expert opinions are mostly based on mathematical modelling using specialist software or dedicated simulation algorithms. This study collates and synthesises the results of tests carried out in a seam section in a colliery within the Upper Silesia Coal Basin, obtained by the outlined methods. Geophysical survey results are interpreted basing on seismic tomography procedures utilising the geo-tomography techniques for velocity field reconstruction in data processing. For comparison, the stress state modelling data are provided, based on conventional engineering solutions applicable to mechanics of deformable media. The actual assessment of the rockburst threat level is based on observations of distributions of the longitudinal wave velocity in relation to the actual value of the vertical component of stress concentration within the coal seam.

2017 ◽  
Vol 21 (3) ◽  
pp. 469-481 ◽  
Author(s):  
Changbin Wang ◽  
Anye Cao ◽  
Guangan Zhu ◽  
Guangcheng Jing ◽  
Jing Li ◽  
...  

Author(s):  
LE Thanh Tam ◽  
Nguyen Minh Chau ◽  
Pham Ngoc Mai ◽  
Ngo Ha Phuong ◽  
Vu Khanh Huyen Tran

The technological revolution 4.0 brings great opportunities, but also cybercrimes to economic sectors, especially to banks. Using secondary data and survey results of 305 bank clients, the main findings of this paper are: (i) there are several types of cybercrimes in the banking sector; (ii) Vietnam is one of the top countries worldwide having hackers and being attacked by hackers, especially the banking sector. Three most common attacks are skimming, hacking and phishing. Number of cybercrime attacks in Vietnam are increasing rapidly over years; (iii) Vietnamese customers are very vulnerable to cybercrime in banking, as more than 58% seem to hear about cybercrimes, and how banks provide services to let them know about their transactions. However, more than 50% do not have any deep knowledge or any measures for preventing cybercrime; (iii) Customers believe in banks, but do not think that banks can deal with cybercrime issues well. They still feel traditional transactions are more secure than e-transactions; (iv) the reasons for high cybercrimes come from commercial banks (low management and human capacity), supporting environment (inadequate), legal framework (not yet strong and strict enough on cybercrimes), and clients (low level of financial literacy). Therefore, several solutions should be carried out, from all stakeholders, for improving the cybersecurity in Vietnamese banks. 


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4349
Author(s):  
Niklas Wulff ◽  
Fabia Miorelli ◽  
Hans Christian Gils ◽  
Patrick Jochem

As electric vehicle fleets grow, rising electric loads necessitate energy systems models to incorporate their respective demand and potential flexibility. Recently, a small number of tools for electric vehicle demand and flexibility modeling have been released under open source licenses. These usually sample discrete trips based on aggregate mobility statistics. However, the full range of variables of travel surveys cannot be accessed in this way and sub-national mobility patterns cannot be modeled. Therefore, a tool is proposed to estimate future electric vehicle fleet charging flexibility while being able to directly access detailed survey results. The framework is applied in a case study involving two recent German national travel surveys (from the years 2008 and 2017) to exemplify the implications of different mobility patterns of motorized individual vehicles on load shifting potential of electric vehicle fleets. The results show that different mobility patterns, have a significant impact on the resulting load flexibilites. Most obviously, an increased daily mileage results in higher electricty demand. A reduced number of trips per day, on the other hand, leads to correspondingly higher grid connectivity of the vehicle fleet. VencoPy is an open source, well-documented and maintained tool, capable of assessing electric vehicle fleet scenarios based on national travel surveys. To scrutinize the tool, a validation of the simulated charging by empirically observed electric vehicle fleet charging is advised.


Author(s):  
Beniamino Di Martino ◽  
Dario Branco ◽  
Luigi Colucci Cante ◽  
Salvatore Venticinque ◽  
Reinhard Scholten ◽  
...  

AbstractThis paper proposes a semantic framework for Business Model evaluation and its application to a real case study in the context of smart energy and sustainable mobility. It presents an ontology based representation of an original business model and examples of inferential rules for knowledge extraction and automatic population of the ontology. The real case study belongs to the GreenCharge European Project, that in these last years is proposing some original business models to promote sustainable e-mobility plans. An original OWL Ontology contains all relevant Business Model concepts referring to GreenCharge’s domain, including a semantic description of TestCards, survey results and inferential rules.


2021 ◽  
Author(s):  
Dariusz Chlebowski ◽  
Zbigniew Burtan

AbstractA variety of geophysical methods and analytical modeling are applied to determine the rockburst hazard in Polish coal mines. In particularly unfavorable local conditions, seismic profiling, active/passive seismic tomography, as well as analytical state of stress calculating methods are recommended. They are helpful in verifying the reliability of rockburst hazard forecasts. In the article, the combined analysis of the state of stress determined by active seismic tomography and analytical modeling was conducted taking into account the relationship between the location of stress concentration zones and the level of rockburst hazard. A longwall panel in the coal seam 501 at a depth of ca.700 m in one of the hard coal mines operating in the Upper Silesian Coal Basin was a subject of the analysis. The seismic tomography was applied for the reconstruction of P-wave velocity fields. The analytical modeling was used to calculate the vertical stress states basing on classical solutions offered by rock mechanics. The variability of the P-wave velocity field and location of seismic anomaly in the coal seam in relation to the calculated vertical stress field arising in the mined coal seam served to assess of rockburst hazard. The applied methods partially proved their adequacy in practical applications, providing valuable information on the design and performance of mining operations.


Author(s):  
Janice E. Cuny ◽  
Robert A. Dunn ◽  
Steven T. Hackstadt ◽  
Christopher W. Harrop ◽  
Harold H. Hersey ◽  
...  

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Meagan Lacy ◽  
Alexandra Hamlett

PurposeIn most higher education institutions, information literacy (IL) instruction is usually considered the purview of librarians, not disciplinary faculty. However, a small but growing body of research indicates that students learn the research process best when these skills are taught in the context of a course or a discipline. For this reason, teaching faculty should share ownership of IL instruction — but how? In this case study, community college librarians explain how they successfully trained faculty to integrate IL into their English Composition courses and teach IL independently.Design/methodology/approachUsing a multimethods approach, the investigators draw on faculty interviews, student surveys, and content analysis of student essays to evaluate the impact of faculty-led IL instruction on student learning after one semester.FindingsFaculty reported that their instruction of IL was improved, and students work better as a result of their collaboration with the librarians. Compared to previous semesters, faculty perceived gains in terms of students’ ability to synthesize and cite evidence in their writing. Student survey results indicate perceived gains in their IL skills, but an assessment of their written work reveals a discrepancy between this perception and the actual application of these skills.Research limitations/implicationsBecause there is no control group, no conclusions can be drawn as to whether faculty-led IL instruction is as effective as librarian-led IL instruction or whether students’ academic performance improves due to faculty teaching IL. However, the purpose of this study is primarily descriptive. It addresses how other libraries may create a culture of shared ownership of IL instruction on their campuses.Practical implicationsThis study offers an alternative model to library instruction and suggests ways instruction librarians can prioritize their outreach and instructional efforts to maximize impact on student learning.Originality/valueWhile much has been written about how librarians can improve IL instruction, few studies mention the role of faculty. This case study starts the conversation.


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