972 research outputs found
A Constitutive Model Describing Damage of Rock and Its Application to Deep Penetration Problem
No full textAccommodating Monetary Policy in Transitional Economies: Particularities
Full text linkThis paper surveys the particularities of monetary policy as a powerful governmental weapon in countries with transitional economies. The paper combines the theoretical analysis with empirical studies. Because in transitional economies the particular channels of monetary policy are diverse, continually changing, and uncertain reduce-form evidence are used to evaluate the empirical evidence. The brief view of relationships between movement in money supply (M1 and M2) and output level (nominal GDP) in Georgia illustrates the close correlation between them. Georgian economy like others transitional economies suffers from “Great Transitional Depression†and macroeconomic equilibrium occurs at recessionary gap. In transition countries initially supply is more elastic and elasticity increases more rapidly than that in developed countries. In these circumstances expansionary monetary policy effects real aggregate economy stimulating economic growth with mild inflation. In industrialized countries accommodating discretionary monetary policy entails cost-push inflation without any change in long-run GDP.monetary policy, transitional economy, reduce-form evidence, long-run economic growth, inflation
Is isotropy restored at small scales in freely decaying strongly stratified turbulence?
No full textWe analyse the scale-dependent anisotropy of homogeneous stratified turbulence. The Ozmidov scale l_N (Ozmidov 1965) helps to compare the relative effects of inertia and of the buoyancy force, and thus to quantify the rise of anisotropy in different scale ranges: at large scales l >> l_N the anisotropy due to strong stratification is dominant, whereas at small scales l << l_N, universal 3D isotropic characteristic of turbulence appear to be restored. We investigate the corresponding dynamics using Direct Numerical Simulations (DNS) in freely decaying turbulence at different stratification rates. We confirm the return to isotropy of the small scales by analyzing the orientation-dependent power spectrum and poloidal/toroidal/density energy modes. To some extent, many characteristics of isotropic universality are restored at small scales but, surprisingly, the density spectrum (also potential energy spectrum) plays a particular role
Correction to: Geochemical Analysis of Cretaceous Shales from the Hazara Basin, Pakistan: Provenance Signatures and Paleo-Weathering Conditions, (J. Mar. Sci. Eng, (2022), 10, (800), 10.3390/jmse10060800)
No full textAddition of an Author In the original publication [1], there was a mistake in the authorship. Muhammad Umar should be added as the co-author. His affiliation is the Department of Earth Sciences, The University of Haripur, Haripur 22620, Pakistan. New Author Contributions Statement Conceptualization, A.G.F. and M.U.; methodology, A.G.F.; software, A.G.F. and H.T.J.; validation, A.G.F., M.U. and H.T.J.; formal analysis, A.G.F., M.U. and H.T.J.; investigation, A.G.F., M.U. and H.T.J.; resources, A.G.F. and M.U.; data curation, A.G.F. and M.U.; writing—original draft preparation, A.G.F. and M.U.; writing—review and editing, H.T.J., F.S., M.A.F.M., G.K. and A.K.J.; visualization, M.U., H.T.J., F.S. and M.A.F.M.; supervision, M.U.; project administration, M.U.; funding acquisition, G.K. and H.T.J. All authors have read and agreed to the published version of the manuscript. © 2022 by the authors. Licensee MDPI, Basel, Switzerland
Modelling of hydrogen-blended dual-fuel combustion using flamelet-generated manifold and preferential diffusion effects
Full text linkIn the present study, Reynolds-Averaged Navier-Stokes simulations together with a novel flamelet generated manifold (FGM) hybrid combustion model incorporating preferential diffusion effects is utilised for the investigation of a hydrogen-blended diesel-hydrogen dual-fuel engine combustion process with high hydrogen energy share. The FGM hybrid combustion model was developed by coupling laminar flamelet databases obtained from diffusion flamelets and premixed flamelets. The model employed three control variables, namely, mixture fraction, reaction progress variable and enthalpy. The preferential diffusion effects were included in the laminar flamelet calculations and in the diffusion terms in the transport equations of the control variables. The resulting model is then validated against an experimental diesel-hydrogen dual-fuel combustion engine. The results show that the FGM hybrid combustion model incorporating preferential diffusion effects in the flame chemistry and transport equations yields better predictions with good accuracy for the in-cylinder characteristics. The inclusion of preferential diffusion effects in the flame chemistry and transport equations was found to predict well several characteristics of the diesel-hydrogen dual-fuel combustion process: 1) ignition delay, 2) start and end of combustion, 3) faster flame propagation and quicker burning rate of hydrogen, 4) high temperature combustion due to highly reactive nature of hydrogen radicals, 5) peak values of the heat release rate due to high temperature combustion of the partially premixed pilot fuel spray with entrained hydrogen/air and then background hydrogen-air premixed mixture. The comparison between diesel-hydrogen dual-fuel combustion and diesel only combustion shows early start of combustion, longer ignition delay time, higher flame temperature and NOx emissions for dual-fuel combustion compared to diesel only combustion
Automation in sensing and raw material characterization - A conceptual framework
No full textThe use of sensor technologies for material characterization is rapidly growing and innovative advancement is observed. However, the use of sensor combinations for a raw material characterization in mining is very limited and automation of the material identification process using a combined sensor signal is not defined. Potential sensor technologies for raw material characterization were evaluated based on the applicability and technological maturity. To ensure a rapid implementation of the Real-time mining (RTM) project concept, mature technologies such as Red Green Blue (RGB) imaging, Visible Near Infrared (VNIR) hyperspectral imaging, Short Wave Infrared (SWIR) hyperspectral imaging, Fourier-Transform Infrared Spectroscopy (FTIR), Laser Induced Breakdown Spectroscopy (LIBS) and Raman were selected. Each selected technology was assessed for automation in sensing and applicability (for characterization of the test case materials). Based on the results the sensor data were further considered for data fusion. The proposed sensor combinations approach encompasses three levels of data fusion: low-level, mid-level and high-level. The data of the different sensors are fused together in order to acquire a wide range of mineral properties within each lithotype and an improved classification and predictive models. The preferred level of data fusion and preferred sensor data combinations will be used to develop a multi-variate statistical interpretation rule which relates combination of sensors signals with raw material properties. Thus a tool which integrates the combined sensor signal with materials properties will be developed and used to automate the material characterization process.Accepted Author ManuscriptResource Engineerin
Experimental and computational study of the influence of pre-damage patterns in unreinforced masonry crack propagation due to induced, repeated earthquakes
No full textInduced seismicity in the north of the Netherlands has recently exposed unprepared, unreinforced masonry structures to considerable earthquake risk. While the ultimate-limit state capacity of the structures is vital to assess the individual’s risk, their behavior during more frequent, lighter earthquakes, leading to ‘lighter damage’, has shown to be strongly linked to economic losses and societal unrest. When observing the light damage caused by minor earthquakes, the existing state of the structure appears to be highly relevant for the final damage intensity and configuration: earthquakes that may have otherwise caused no apparent damage, may intensify existing damage. In particular, incipient damage due to settlements is common in the baked-clay and calcium-silicate brick masonry structures of the region.This paper details the study of full-scale laboratory walls, pre-damaged following typical (crack) patterns caused by settlements and tested with quasi-static lateral loads. The aggravation of the damage during a relevant number of load cycles is monitored using full-field digital image correlation. The damage is quantified objectively using a purposely-developed damage parameter.The tests are used (together with previous studies) to further calibrate computational finite element models, which coupled with detailed soil-structure interaction boundary conditions, are then employed to assess a larger number of structural geometries and pre-damaged configurations exposed to (repeated) induced earthquake acceleration histories.Both experimental and computational approaches show that settlement pre-damage in masonry structures increases the likelihood and the amount of further damage. This is more easily observed when some initial, yet limited damage exists and the masonry wall is exposed to moderate earthquake vibrations in the order of 30 millimeters per second.Accepted Author ManuscriptApplied Mechanic
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