20,899 research outputs found
Turbocharger speed monitoring based on vibration measurements for diesel engine management
No full textA Systematic Review of Industry 4.0 Maturity Models: Applicability in the O&G Upstream Industry
No full textThe study aims to review the currently available Industry 4.0 (I4.0) maturity models (MMs) for manufacturing industries and analyse their applicability in the oil and gas (O&G) upstream sector. Knowing that the growth in demand for energy through crude oil and natural gas is still viable over the next decade, there is the drive to ensure sustenance and improvement in production. The study sees an opportunity in harnessing the gains of Industry 4.0 technologies for better solution-driven strategies in production processes, equipment availability and reliability which would translate into higher production performance. So, a review on the Industry 4.0 MMs is considered important. A systematic and in-depth literature review was performed to identify the specific requirements of this industry. This study examined the key characteristics of the O&G upstream sector and identified research gaps that need to be addressed to successfully support this industry for Industry 4.0 implementation. An Industry 4.0 MM that reflects the industrial realities for this industry more accurately from insights drawn from reviews of existing MMs is proposed. The review of 19 selected Industry 4.0 MMs revealed that the existing MMs are not a direct fit for the O&G upstream industry. Only a few of the models were clear on validation but with subjectivity, low number of persons and industries involved as limitations; none of the models confirmed validation with the O&G industry. There are varying views on the model dimensions and maturity levels by each author and not all required areas specific to the O&G industries were acknowledged by the models. An MM specific to this industry is therefore required. Although the journey of digitisation has commenced in the O&G industry, a reduction with the challenges of transition towards Industry 4.0 implementation and provision of support for improved efficiency is assured using a robust MM, as proposed in this paper
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
QUALIFYING FEATURES OF THE COMPOSITION OF EVASION FROM PAYMENT OF SINGLE FEE FOR OBLIGATORY STATE SOCIAL INSURANCE AND INSURANCE CONTRIBUTIONS FOR OBLIGATORY STATE PENSION INSURANCE AND DELIMITATION FROM RELATED OFFENCES
No full textO. Henry reviews his writing techniques
No full textAmerican author William Sydney Porter, better known by his pen name "O. Henry," reviews his writing techniques
Resourcefulness quantification approach for resilient communities and countries
Get PDFAvailability of resources is one of the primary criteria for communities to attain a high resilience level during disaster events. This paper introduces a new approach to evaluate resourcefulness at the community and national scales. Resourcefulness is calculated using a proposed composite resourcefulness index, which is a combination of several resourcefulness indicators. To build the resourcefulness index, resourcefulness indicators representing the different aspects of resourcefulness are collected from renowned literary publications. Every indicator is assigned a measure to make it quantifiable. Time-history data for the measures are needed to perform the analysis. While these data could be obtained from different sources, acquiring a full set of data is quite challenging. Hence, to account for missing data, the Multiple Imputation (MI) and the Markov Chain Monte Carlo (MCMC) data imputation methods are adopted. The data are then normalized, assigned weights, and aggregated to obtain the resourcefulness index. A case study is performed to demonstrate the applicability of the approach. The resourcefulness indexes of two countries, namely the United States and Italy, are evaluated. Results show that resourceful communities/countries are more resilient during disaster events as they have more tools to come up with solutions. It is also shown that knowing the current resourcefulness level helps in better identifying what aspects should be improved.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Integral Design & Managemen
Cooling rates of neutron stars and the young neutron star in the Cassiopeia A supernova remnant
No full textWe explore the thermal state of the neutron star in the Cassiopeia A supernova remnant using the recent result of Ho & Heinke that the thermal radiation of this star is well described by a carbon atmosphere model and the emission comes from the entire stellar surface. Starting from neutron star cooling theory, we formulate a robust method to extract neutrino cooling rates of thermally relaxed stars at the neutrino cooling stage from observations of thermal surface radiation. We show how to compare these rates with the rates of standard candles – stars with non-superfluid nucleon cores cooling slowly via the modified Urca process. We find that the internal temperature of standard candles is a well-defined function of the stellar compactness parameter x=rg/R, irrespective of the equation of state of neutron star matter (R and rg are circumferential and gravitational radii, respectively). We demonstrate that the data on the Cassiopeia A neutron star can be explained in terms of three parameters: f?, the neutrino cooling efficiency with respect to the standard candle; the compactness x; and the amount of light elements in the heat-blanketing envelope. For an ordinary (iron) heat-blanketing envelope or a low-mass (? 10?13 M?) carbon envelope, we find the efficiency f?? 1 (standard cooling) for x? 0.5 and f?? 0.02 (slower cooling) for a maximum compactness x? 0.7. A heat blanket containing the maximum mass (?10?8 M?) of light elements increases f? by a factor of 50. We also examine the (unlikely) possibility that the star is still thermally non-relaxe
Probabilistic framework to evaluate the resilience of engineering systems using Bayesian and dynamic Bayesian networks
Get PDFResilience indicators are a convenient tool to assess the resilience of engineering systems. They are often used in preliminary designs or in the assessment of complex systems. This paper introduces a novel approach to assess the time-dependent resilience of engineering systems using resilience indicators. A Bayesian network (BN) approach is employed to handle the relationships among the indicators. BN is known for its capability of handling causal dependencies between different variables in probabilistic terms. However, the use of BN is limited to static systems that are in a state of equilibrium. Being at equilibrium is often not the case because most engineering systems are dynamic in nature as their performance fluctuates with time, especially after disturbing events (e.g. natural disasters). Therefore, the temporal dimension is tackled in this work using the Dynamic Bayesian Network (DBN). DBN extends the classical BN by adding the time dimension. It permits the interaction among variables at different time steps. It can be used to track the evolution of a system's performance given an evidence recorded at a previous time step. This allows predicting the resilience state of a system given its initial condition. A mathematical probabilistic framework based on the DBN is developed to model the resilience of dynamic engineering systems. Two illustrative examples are presented in the paper to demonstrate the applicability of the introduced framework. One example evaluates the resilience of Brazil. The other one evaluates the resilience of a transportation system.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Integral Design & Managemen
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