scholarly journals A Method of Comparative Evaluation of the Drive Units of Two Bucket Elevators—A Case Study

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7439
Author(s):  
Piotr Sokolski ◽  
Justyna Sokolska

Bucket elevators are applied in many industries for bulk material handling. One of the main requirements for these devices is their high operational reliability. This applies in particular to power units that must operate continuously without failure. This article presents a comparative assessment of the drive units of two bucket elevators. The vibration intensity of their bearing units was used as the basis for the comparison. The evaluation was carried out using three independent methods based on the vibration velocity analysis: in the time domain, in the frequency domain and using the probabilistic approach.

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Mansour Alsaleh ◽  
Noura Alomar ◽  
Monirah Alshreef ◽  
Abdulrahman Alarifi ◽  
AbdulMalik Al-Salman

The widespread adoption of web vulnerability scanners and the differences in the functionality provided by these tool-based vulnerability detection approaches increase the demand for testing their detection effectiveness. Despite the advantages of dynamic testing approaches, the literature lacks studies that systematically evaluate the performance of open source web vulnerability scanners. The main objectives of this study are to assess the performance of open source scanners from multiple perspectives and to examine their detection capability. This paper presents the results of a comparative evaluation of the security features as well as the performance of four web vulnerability detection tools. We followed this comparative assessment with a case study in which we evaluate the level of agreement between the results reported by two open source web vulnerability scanners. Given that the results of our comparative evaluation did not show significant performance differences among the scanners while the results of the conducted case study revealed high level of disagreement between the reports generated by different scanners, we conclude that the inconsistencies between the reports generated by different scanners might not necessarily correlate with their performance properties. We also present some recommendations for helping developers of web vulnerabilities scanners to improve their tools’ capabilities.


Author(s):  
V.I. Midlenko ◽  
N.I. Belonogov ◽  
O.V. Midlenko ◽  
A.L. Charyshkin

The aim of the paper is to conduct a comparative assessment of bowel decompression methods in operations on toxic widespread peritonitis. Materials and Methods. The authors examined 162 patients with widespread peritonitis of various etiologies. Using generally accepted methods, they compared treatment results using one of the three methods of intestinal decompression: cecostomy, nasointestinal intubation, and cecostomy with intubation of the small intestine. Results. It was detected that in case of small intestine intubation through the cecostomy (in comparison with other methods), intra-abdominal pressure returned to normal on the 2nd day, and in case of cecostomy or nasointestinal intubation – on the 5th and 7th day, respectively. Also, decrease in intoxication indicators was observed 2 days earlier than usual. Conclusion. Intubation of the small intestine through the cecostoma provides the most adequate intestinal decompression in patients with advanced toxic peritonitis. Early normalization of intra-abdominal pressure in patients with advanced toxic peritonitis improves treatment outcomes. Keywords: widespread peritonitis, intestinal decompression. Цель – сравнительная оценка способов декомпрессии кишечника при операциях по поводу распространённого перитонита в токсической стадии. Материалы и методы. Наблюдали 162 пациента с распространённым перитонитом различной этиологии. С использованием общепринятых методик сравнивались результаты лечения при применении одного из трёх способов декомпрессии кишечника: цекостомии, назоинтестинальной интубации и наложения цекостомы с интубацией тонкой кишки. Результаты. Установлено, что при использовании интубации тонкого кишечника через цекостому, в сравнении с другими применявшимися нами способами, внутрибрюшное давление нормализовалось на второй день, а при использовании цекостомии или назоинтестинальной интубации – на 5-й и 7-й дни соответственно. Также на 2 сут раньше происходило снижение показателей интоксикации. Выводы. Наиболее адекватную декомпрессию кишечника у пациентов с распространённым перитонитом в токсической стадии обеспечивает интубация тонкого кишечника через цекостому. Ранняя нормализация внутрибрюшного давления у пациентов с распространённым перитонитом в токсической стадии позволяет улучшить результаты лечения. Ключевые слова: распространённый перитонит, декомпрессия кишечника.


Geophysics ◽  
2021 ◽  
pp. 1-50
Author(s):  
German Garabito ◽  
José Silas dos Santos Silva ◽  
Williams Lima

In land seismic data processing, the prestack time migration (PSTM) image remains the standard imaging output, but a reliable migrated image of the subsurface depends on the accuracy of the migration velocity model. We have adopted two new algorithms for time-domain migration velocity analysis based on wavefield attributes of the common-reflection-surface (CRS) stack method. These attributes, extracted from multicoverage data, were successfully applied to build the velocity model in the depth domain through tomographic inversion of the normal-incidence-point (NIP) wave. However, there is no practical and reliable method for determining an accurate and geologically consistent time-migration velocity model from these CRS attributes. We introduce an interactive method to determine the migration velocity model in the time domain based on the application of NIP wave attributes and the CRS stacking operator for diffractions, to generate synthetic diffractions on the reflection events of the zero-offset (ZO) CRS stacked section. In the ZO data with diffractions, the poststack time migration (post-STM) is applied with a set of constant velocities, and the migration velocities are then selected through a focusing analysis of the simulated diffractions. We also introduce an algorithm to automatically calculate the migration velocity model from the CRS attributes picked for the main reflection events in the ZO data. We determine the precision of our diffraction focusing velocity analysis and the automatic velocity calculation algorithms using two synthetic models. We also applied them to real 2D land data with low quality and low fold to estimate the time-domain migration velocity model. The velocity models obtained through our methods were validated by applying them in the Kirchhoff PSTM of real data, in which the velocity model from the diffraction focusing analysis provided significant improvements in the quality of the migrated image compared to the legacy image and to the migrated image obtained using the automatically calculated velocity model.


2016 ◽  
Vol 35 (1) ◽  
pp. 485-492 ◽  
Author(s):  
He Ma ◽  
Hailiang Wang ◽  
Chuang He ◽  
Zuyuan Zhang ◽  
Xiao Ma
Keyword(s):  

Author(s):  
Nicholas M. Veikos ◽  
Ferdinand Freudenstein

Abstract Part I of this paper (5) summarized the previous work and has described the theoretical and computational aspects of a computer-aided procedure which has been developed by the authors for the dynamic analysis of roller chain drives. Lagrange’s equations of motion have been derived by assuming the roller chain to behave as a series of masses lumped at the roller centers and connected by bars of constant axial stiffness. The equations of motion are solved in the time domain until steady state conditions are achieved.


2021 ◽  
Author(s):  
Maria Vittoria Gargiulo ◽  
Alexander Garcia ◽  
Ortensia Amoroso ◽  
Paolo Capuano

<p>To the welfare of both economy and communities, our society widely exploits geo-resources. Nevertheless, with benefits come risks and even impacts. Understanding how a given project intrinsically bares such risks and impacts is of critical importance for both industry and society. In particular, it is fundamental to distinguish between the specific impacts related to exploiting a given energy resource and those shared with the exploitation of other energy resources. In order to do so, it is useful to differentiate impacts in two categories: routine impacts – caused by ordinary routine operations, investigated by Life-cycle assessment with a deterministic approach – and risk impacts – caused by incidents due to system failure or external events, investigated by risk assessments with a probabilistic approach. The latter category is extremely interesting because it includes low probability/high consequences events, which may not be completely independent or unrelated, causing the most disastrous and unexpected damages. For this reason, it is becoming more and more crucial to develop a strategy to assess not only the single risks but also their possible interaction and to harmonize the result obtained for different risk sources. Of particular interest for this purpose is the Multi-Hazard/Multi-Risk Assessment.</p><p>The aim of our work is to present an approach for a comprehensive analysis of impacts of geo-resource development projects. Routine operations as well as risks related to extreme events (as e.g.,seismic or meteorological) are linked using a Multi-Hazard Risk (MHR) approach built upon a Life-Cycle analysis (LCA). Given the complexity of the analysis, it is useful to adopt a multi-level approach: (a) an analysis of routine operations, (b) a qualitative identification of risk scenarios and (c) a quantitative multi-risk analysis performed adopting a bow-tie approach. In particular, after studying the two tools, i.e. LCA and MRA, we have implemented a protocol to interface them and to evaluate certain and potential impacts.</p><p>The performance of the proposed approach is illustrated on a virtual site (based on a real one) for geothermal energy production. As a result, we analyse the outcome of the LCA, identify risk-bearing elements and events, to finally obtain harmonised risk matrices for the case study. Such approach, on the one hand, can be used to assess both deterministic and stochastic impacts, on the other hand, can also open new perspective in harmonizing them. Using the LCA outputs as inputs of the MRA can allow the analyst to focus on particular risk pathways that could otherwise seem less relevant but can open new perspective in the risk/impact evaluation of single elements, as we show in this case study.</p><p>This work has been supported by S4CE ("Science for Clean Energy") project, funded from the European Union’s Horizon 2020 - R&I Framework Programme, under grant agreement No 764810 and by PRIN-MATISSE (20177EPPN2) project funded by Italian Ministry of Education and Research.</p>


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