Wyniki wyszukiwania - BazTech

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The aftershock sequence at a deep nickel mine: temporal and spatial distribution, magnitude distribution, and aftershock decay following major events

Ma Xu, Westman Erik, Malek Farid, Nie Baisheng, Lin Shuangshuang

Acta Geophysica

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2022

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Vol. 70, no 3

1241--1252

EN

Mining-induced seismic events greatly threaten safety of underground workers and studying major seismic events would help mitigate hazards in deep mines. Characterizing the aftershock sequence of major events can contribute to developing a reentry protocol after major events occur at mines. This study uses two major events and their aftershock sequences at Creighton Mine to investigate properties of aftershock sequences focusing on the magnitude of completeness and aftershock decay pattern. Two major events with moment magnitude 3.1 and 1.4 are analyzed, respectively, and their aftershock sequence are examined in this study. The optimal magnitude of completeness is rigorously determined by evaluating the goodness of ft using the maximum likelihood method. Then, parameters of aftershock decay using the MOL are estimated. We identify that the p-value of the two studied events is slightly larger than 0.8. This parametrization process using the MOL can assist in better understanding aftershock sequences of mining-induced major events and therefore mitigating seismic hazards in mining by potentially helping establish a reentry protocol based on the seismicity dropping below a certain rate. For establishing a reentry protocol, the study of the two events can be considered as a methodological work and a future statistical work for many events with different magnitudes and locations to establish the range of the MOL parameters is needed.

2

Wpływ warunków skrawania ekologicznego (MQCL i MOL) na strukturę geometryczną obrobionej powierzchni ze stali nierdzewnej 2H13

Maruda R. W.

Przegląd Mechaniczny

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2014

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nr 10

36--40

PL

W pracy przedstawiono wyniki badań wpływu sposobu chłodzenia na wybrane parametry chropowatości powierzchni obrobionej stali nierdzewnej ze stali 2H13. Porównywano metody skrawania na sucho, chłodzenia sprężonym powietrzem, metodami Minimum Quantity Cooling Lubrication (MQCL) oraz Minimum Quantity Lubrication (MOL) przy toczeniu z różnymi posuwami i prędkościami skrawania. Ustalono wpływ parametrów tworzenia mgły emulsyjnej i olejowej na wybrane parametry chropowatości. Przy planowaniu badań wykorzystano metodę Parameter Space lnvestigation. Metody MOL i MOCL okazały się bardziej skuteczne przy skrawaniu stali nierdzewnej, zapewniając mniejsze wartości parametrów chropowatości. Najniższe wartości uzyskano dla metody MOL, która powoduje zmniejszenie wartości parametru Ra i Rz od 2% do 86% i parametru RSm od 2% do 50% w porównaniu z obróbką na sucho.

EN

Research results of the impact of a cooling method on selected parameters of the roughness of a machined surface were presented in the paper. Methods of dry machining, compressed air cooling Minimum-Ouantity-Cooling-Lubrication (MOCL) as well as Minimum-Ouantity-Lubrication (MOL) while turning of 2H13 stainless steel with different feed rase and cutting speed were aIso compared. The impact of volumetric air flow and the liguid mass, which were the parameters of creating emulsion and oil mist, on the selected parameters of roughness were aIso determined. The research was carried out according to the Parameter Space lnvestigation method. MOCL and MOL methods proved to be more effective in cutting stainless steel, providing the smaller values of the roughness parameters. The Iowest values were obtained for the MOL method which resulted in reducing the value of Ra and Rz parameter from 2% to 86% as well as RSm parameter from 2% to 50% compared with the dry processing.

3

PLM optimization with cooperation of PMS in production stage

Paavel M., Snatkin A., Karjust K.

Archives of Materials Science and Engineering

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2013

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Vol. 60, nr 1

38--45

EN

Purpose: To present a short overview of PLM and its directions including evolution, different phases of PLM and Closed-loop PLM. To describe a new approach in order to improve the closed-loop lifecycle by using production monitoring systems at an early stage of the lifecycle. Monitoring of products in their early life stages in production processes and to use this information for the improvement of the product development and implementation process. Design/methodology/approach: Implementation of a production monitoring system plays an important role in our approach. Sensors that are part of a production monitoring system are sending valuable data from the production to the PLM database where it can be used for production development and analysis. Findings: It is demonstrated that installation of the production monitoring system improved product lifecycle at the beginning of their lifecycle. Feedback from production monitoring systems helps to make better conclusions and quicker decisions in the development phase and gives real-time input to the analysis process. Research limitations/implications: Production monitoring systems improve product lifecycle management in the early stages but do not support the product directly in the other life stages. Decisions can be made only based on this information. Practical implications: Information gathered by production monitoring systems could help to modify the production development and implementation process . Also afterwards the information can be used to identify deviations and mistakes. All this is necessary to fill the gaps in product lifecycle. Originality/value: The proposed installation of production monitoring systems improves new data income to the system that provides better decision making opportunities. Based on this real-time information, it is easier to make changes in the product development phases.

4

Comparison ODE theorems related to the method of lines

Leszczyński H.

Journal of Applied Analysis

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2011

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Vol. 17, nr 1

137-154

EN

We prove a comparison theorem for an ODE and DAE system which arises from the method of lines. Under a Perron comparison condition on the functional dependence and a specific Lipschitz and (W+) condition on the classical argument, we obtain strong uniqueness criteria.