3,621 research outputs found
Calculating the Connectivity of a Directed Graph
No full textMatula, David W.; Vohra, Rakesh V.. (1987). Calculating the Connectivity of a Directed Graph. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/4759
A parametric worst case analysis for a machine scheduling problem
Get PDFIncludes bibliographical references (p. 16).Supported by the NSF. 84151517-ECS Supported by a Dean's Summer Fellowship form the College of Business of the Ohio State University.Paul Mireault, Rakesh Vohra and James B. Orlin
Optimal Design of Capsule Transporting Pipeline carrying Spherical Capsules
Get PDFA capsule pipeline transports material or cargo in capsules propelled by fluid flowing through a pipeline. The cargo may either be contained in capsules (such as wheat enclosed inside sealed cylindrical containers), or may itself be the capsules (such as coal compressed into the shape of a cylinder or sphere). As the concept of capsule transportation is relatively new, the capsule pipelines need to be designed optimally for commercial viability. An optimal design of such a pipeline would have minimum pressure drop due to the presence of the solid medium in the pipeline, which corresponds to minimum head loss and hence minimum pumping power required to drive the capsules and the transporting fluid. The total cost for the manufacturing and maintenance of such pipelines is yet another important variable that needs to be considered for the widespread commercial acceptance of capsule transporting pipelines. To address this, the optimisation technique presented here is based on the least-cost principle. Pressure drop relationships have been incorporated to calculate the pumping requirements for the system. The maintenance and manufacturing costs have been computed separately to analyse their effects on the optimisation process. A design example has been included to show the usage of the model presented. The results indicate that for a specific throughput, there exists an optimum diameter of the pipeline for which the total cost for the piping system is at its minimum
Performance of a Vertical Axis Wind Turbine under Accelerating and Decelerating Flows
Get PDFRapid increase in global energy requirements has resulted in considerable attention towards energy generation from the renewable energy sources. In order to meet renewable energy targets, harnessing energy from all available resources including
those from urban environment is required. Vertical Axis Wind Turbines (VAWTs) are seen as a potential way of utilising urban energy sources. Most of the research on the wind turbines constitutes condition monitoring and performance optimisation of VAWTs under a constant velocity of air where the transient effects have not been accounted. The inconsistent behaviour of the wind may change the nature of the flow field around the VAWT which could decrease its life cycle. This study is an attempt to use Computational Fluid Dynamic’s techniques to study and analyse the performance of a wind turbine under accelerating and
decelerating air inlet velocity. The performance of a VAWT is monitored under an accelerated and decelerated gust of the value 1.09m/s² characterised by change in velocity from 4m/sec to 10m/sec. The instantaneous torque output varies significantly when a gust of air is applied to the turbine. Furthermore the torque outputs during accelerating and decelerating flows vary, highlighting the effect of transient phenomena. This abrupt change in the instantaneous torque output of the turbine may give rise to highly transient loads on the turbine’s structure which may induce heavy stresses on the turbine leading to structural failure. It has been shown that CFD can be used as an effective tool to predict the performance outputs of a VAWT under varying flow
conditions
Computational Fluid Dynamics based Flow Diagnostics in Hydraulic Capsule Pipeline Bends
No full textHydraulic Capsule Pipelines (HCPs) are the third generation of pipelines that are based on the transport of hollow spherical, or cylindrical, capsules by the force exerted on them from the carrier fluid, which is water. These hollow capsules can be filled with a variety of cargo goods, such as minerals, jewellery etc. The hydrodynamics of this transport phenomena is quite complex, and researchers around the globe have been trying to analyse the hydrodynamics of such systems. However, most of these studies are based on experimental investigations, which can provide reasonably accurate results for the pressure drop etc. across the pipeline. However, the flow structure within HCPs cannot be easily mapped using experimental facilities. Furthermore, in case of pipe bends, the difficulty level increases exponentially due to a constant curvature in the geometry of the pipeline, and hence mounting the flow measuring instruments can be very challenging. The present study makes use of the advanced Computational Fluid Dynamics (CFD) based solvers, with powerful computing services, in order to analyse the flow structure within HCP bends. It is expected that this information can provide valuable information to the HCP designers, not only to calculate pressure drop across HCP bends, but in order to select the correct size etc. bends for the pipeline
Dominant Strategy Mechanisms with Multidimensional Types
Get PDFThis paper provides a characterization of dominant strategy
mechanisms with quasi-linear utilities and multi-dimensional types
for a variety of preference domains. These characterizations are
in terms of a monotonicity property on the underlying allocation
rule
Corrigendum: Capital Inflows and House Prices: Aggregate and Regional Evidence from China
No full textIn the paper ‘Capital Inflows and House Prices: Aggregate and Regional Evidence from China’ by H. An, et al., printed in the December 2016 issue, there was a missing acknowledgement section for funding resources.
On page 451, the acknowledgement section should appear after the corresponding information as:
“Correspondence: Rakesh Gupta, Department of Accounting, Finance and Economics, Griffith Business School, Griffith University, Nathan Campus QLD 4111. [email protected]
*This work was financially supported by the Humanities and Social Science Foundation of Ministry of Education of China (16YJA790001).”
The author apologises for this error and any confusion it may have caused.No Full Tex
Emerging contours of financial regulation: challenges and dynamics.
Get PDFThe current ongoing financial crisis is attributed to a variety of factors such as the developments in the subprime mortgage sector, excessive leverage, lax financial regulation and supervision, and global macroeconomic imbalances. At a fundamental level, however, the crisis also reflects the effects of long periods of excessively loose monetary policy in the major advanced economies during the early part of this decade. The theory and belief of efficient and rational markets have been severely discredited by the current crisis. There is, therefore, a growing agreement for much strengthened, and perhaps, intrusive regulation and supervision in the financial sector. Hitherto unregulated institutions, markets and instruments will now have to be brought under the regulatory framework. A more developed macroprudential approach will be important. Once the current financial crisis is beyond us, minimum regulatory capital requirements would need to be signifi cantly above existing Basel rules, with emphasis on Tier I capital, and supported by a maximum gross leverage ratio. Liquidity regulation and supervision must be recognised as of equal importance to capital regulation, reinforced by an effective global liquidity framework for managing liquidity in large, cross-border fi nancial institutions. The issue of remuneration in the fi nancial sector would require reforms on an industry-wide basis so that improved risk management and compensation practices by some systemically important firms are not undermined by the unsound practices of others. Whereas the suggested reform principles are being increasingly well accepted, many challenges will arise on their modes of implementation, and their practicality. For instance, once normalcy returns, the fi nancial industry will do its utmost to resist the requirements for higher capital at that time. From the point of view of emerging market economies (EMEs), the volatility in capital flows – mainly the outcome of extant monetary policy regimes in developed countries – has led to severe problems in both macro management and financial regulation. This will remain a challenge since there is little international discussion on this issue. Finally, as the global economy starts recovery, a calibrated exit from the prevalent unprecedented accommodative monetary policy will have to be ensured to avoid the recurrence of the financial crisis being experienced now.
Collected Papers (Papers of Mathematics or Applied Mathematics), Volume V
No full textThis volum includes 37 papers of mathematics or applied mathematics written by the author alone or in collaboration with the following co-authors: Cătălin Barbu, Mihály Bencze, Octavian Cira, Marian Niţu, Ion Pătraşcu, Mircea E. Şelariu, Rajan Alex, Xingsen Li, Tudor Păroiu, Luige Vlădăreanu, Victor Vlădăreanu, Ştefan Vlăduţescu, Yingjie Tian, Mohd Anasri, Lucian Căpitanu, Valeri Kroumov, Kimihiro Okuyama, Gabriela Tonţ, A. A. Adewara, Manoj K. Chaudhary, Mukesh Kumar, Sachin Malik, Alka Mittal, Neetish Sharma, Rakesh K. Shukla, Ashish K. Singh, Jayant Singh, Rajesh Singh, V.V. Singh, Hansraj Yadav, Amit Bhaghel, Dipti Chauhan, V. Christianto, Priti Singh, and Dmitri Rabounski
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