Betonun zamana bağlı deformasyonlarının tahmini

In this study, the main objective is to analyze the creep, the basic creep and the shrinkage deformations of normal and low strength concretes with or without mineral admixture and to  investigate of the agreement between the results that have been gained using creep and shrinkage prediction methods and the experimental values of creep and shrinkage. Eight concrete mixtures at two water/binder ratios (0,55 and 0,70) were produced by using either only cement as a binder or by partially replacing it with silica fume, fly ash or ground granulated blast furnace slag. As the experimental values taken from concretes with and without mineral admixtures are compared, it was found that the mineral admixtures did not have a significant effect on the time dependent deformations of low strength concretes, whereas in normal strength concretes they caused the creep and shrinkage values to decrease. On the other hand, comparison was made between the experimental results and the creep and shrinkage values that were obtained by applying creep and shrinkage prediction models; ACI, CEB-FIP, B3, GL2000. The results show that the differences between the experimental values of shrinkage and the values that were predicted by B3 and GL2000 models were within the accepted intervals (±100 D) whereas the values predicted by CEB-FIP and ACI 209 were outside those intervals. The deviations of the values of creep function (elastic deformation + creep deformation divided by the applied stress) from the experimental results were found to be outside the accepted intervals (±33 D/MPa). Keywords: Creep, shrinkage, time dependent deformations, elastic deformation.Bu çalışmada, normal ve düşük dayanımlı, katkısız ve mineral katkılı betonların sünme, temel sünme ve rötre deformasyonları incelenmekte, rötre ve sünme tahmin modelleri kullanılarak elde edilen sonuçların, deneysel rötre ve sünme değerlerine uygunluğu belirlenmektedir. Mineral katkılar olarak silis dumanı, uçucu kül ve öğütülmüş yüksek fırın cürufu, rötre ve sünme deformasyonlarının deneysel değerlerinin  tahmin edilmesi için ise ACI, CEB-FIP, B3 ve GL2000 modelleri kullanılmaktadır. Mineral katkılı ve referans betonlardan elde edilen deneysel sonuçlar karşılaştırıldığında, mineral katkıların düşük dayanımlı betonların zamana bağlı deformasyonları üzerinde belirgin bir etkisi olmadığı, buna karşın, normal dayanımlı betonlarda sünme ve rötre değerlerinde düşüşe neden olduğu belirlenmektedir. Rötre ve sünme tahmin modelleri ile elde edilen değerler analiz edildiğinde, B3 ve GL2000 modelleri yardımıyla elde edilen rötre tahmin sonuçları ile deneysel sonuçlar arasındaki farkların kabul edilen sınırlar içerisinde kaldığı; sünme fonksiyonu tahmin değerlerinin kabul edilir sınırları aştığı görülmektedir.  Anahtar Kelimeler: Sünme, rötre, zamana bağlı deformasyonlar, elastik deformasyon

Are greenhouse gas signals of Northern Hemisphere winter extra-tropical cyclone activity dependent on the identification and tracking algorithm?

For Northern Hemisphere extra-tropical cyclone activity, the dependency of a potential anthropogenic climate change signal on the identification method applied is analysed. This study investigates the impact of the used algorithm on the changing signal, not the robustness of the climate change signal itself. Using one single transient AOGCM simulation as standard input for eleven state-of-the-art identification methods, the patterns of model simulated present day climatologies are found to be close to those computed from re-analysis, independent of the method applied. Although differences in the total number of cyclones identified exist, the climate change signals (IPCC SRES A1B) in the model run considered are largely similar between methods for all cyclones. Taking into account all tracks, decreasing numbers are found in the Mediterranean, the Arctic in the Barents and Greenland Seas, the mid-latitude Pacific and North America. Changing patterns are even more similar, if only the most severe systems are considered: the methods reveal a coherent statistically significant increase in frequency over the eastern North Atlantic and North Pacific. We found that the differences between the methods considered are largely due to the different role of weaker systems in the specific methods

IMILAST: a community effort to intercompare extratropical cyclone detection and tracking algorithms

The variability of results from different automated methods of detection and tracking of extratropical cyclones is assessed in order to identify uncertainties related to the choice of method. Fifteen international teams applied their own algorithms to the same dataset—the period 1989–2009 of interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERAInterim) data. This experiment is part of the community project Intercomparison of Mid Latitude Storm Diagnostics (IMILAST; see www.proclim.ch/imilast/index.html). The spread of results for cyclone frequency, intensity, life cycle, and track location is presented to illustrate the impact of using different methods. Globally, methods agree well for geographical distribution in large oceanic regions, interannual variability of cyclone numbers, geographical patterns of strong trends, and distribution shape for many life cycle characteristics. In contrast, the largest disparities exist for the total numbers of cyclones, the detection of weak cyclones, and distribution in some densely populated regions. Consistency between methods is better for strong cyclones than for shallow ones. Two case studies of relatively large, intense cyclones reveal that the identification of the most intense part of the life cycle of these events is robust between methods, but considerable differences exist during the development and the dissolution phases

The role of digital consciousness in change management

The article deals with the problems of change management in the new conditions of superfragility of the BANI-world. Interpretations of the concepts of “transcendental thinking”, “digital consciousness”, “immersiveness” are given. The prerequisites substantiating the idea that transcendental thinking needs to be cultivated in the organisation in order to achieve effective management flexibility are presented. The latter is formed in the broader context of the digital consciousness organisational culture, without which it is impossible to set up the organisation’s staff for a positive perception of immersive management practices and the digital technologies productive use. Barriers to the transformation of organisational processes have been identified. It has been shown that the digital transformation of the organisation increases the resistance on the part of the staff by digital resistance plane, when aversion to any change correlates with a lack of ­understanding of digital opportunities. The relationship between the conceptual methodologies of digital consciousness and metacognition and the effectiveness of the formation of a change management strategy has been established

Digital consciousness as a factor of human capital formation in integration processes

The article studies problems of reintegration of social spaces in the conditions of new reality. The concepts of “reintegration”, “digital consciousness” and “human capital” have been interpreted. The concept of reintegration process based on the multiplicative effct of resulting sum of cognitive, axiological, and organizational vectors of social space reassembly on the basis of public support for its digital transformation has been presented. The paper presents assumptions justifying the idea that achieving effctive reintegration is primarily associated with economic development of a territory so it is necessary to form human capital on the basis of digital consciousness. In the modern world, digital consciousness is becoming a dominant cognitive factor as digital technologies are increasingly penetrating our lives and changing the way people interact. However, developing digital consciousness requires continuous learning and skill development. It can be achieved through professional training, self-education, and participation in projects related to digital transformation. Thus, digital consciousness can be considered as a factor ofhuman capital growth that can help people adapt to changing labor market conditions and work successfully in digital economy

Responses of Arctic cyclones to biogeophysical feedbacks under future warming scenarios in a regional Earth system model

Arctic cyclones, as a prevalent feature in the coupled dynamics of the Arctic climate system, have large impacts on the atmospheric transport of heat and moisture and deformation and drifting of sea ice. Previous studies based on historical and future simulations with climate models suggest that Arctic cyclogenesis is affected by the Arctic amplification of global warming, for instance, a growing land-sea thermal contrast. We thus hypothesize that biogeophysical feedbacks (BF) over the land, here mainly referring to the albedo-induced warming in spring and evaporative cooling in summer, may have the potential to significantly change cyclone activity in the Arctic. Based on a regional Earth system model (RCA-GUESS) which couples a dynamic vegetation model and a regional atmospheric model and an algorithm of cyclone detection and tracking, this study assesses for the first time the impacts of BF on the characteristics of Arctic cyclones under three IPCC Representative Concentration Pathways scenarios (i.e. RCP2.6, RCP4.5 and RCP8.5). Our analysis focuses on the spring- and summertime periods, since previous studies showed BF are the most pronounced in these seasons. We find that BF induced by changes in surface heat fluxes lead to changes in land-sea thermal contrast and atmospheric stability. This, in turn, noticeably changes the atmospheric baroclinicity and, thus, leads to a change of cyclone activity in the Arctic, in particular to the increase of cyclone frequency over the Arctic Ocean in spring. This study highlights the importance of accounting for BF in the prediction of Arctic cyclones and the role of circulation in the Arctic regional Earth system