scholarly journals On horizontal immersions of discs in fat distributions of type (4,6)

2021 ◽  
pp. 1-29
Author(s):  
Aritra Bhowmick

In this paper, we discuss horizontal immersions of discs in certain corank-2 fat distributions on 6-dimensional manifolds. The underlying real distribution of a holomorphic contact distribution on a complex 3 manifold belongs to this class. The main result presented here says that the associated nonlinear PDE is locally invertible. Using this we prove the existence of germs of embedded horizontal discs.

Author(s):  
Niklas Wehbring ◽  
Raphael Bleilevens ◽  
Julian Saat ◽  
Maximilian Rose ◽  
Albert Moser

2021 ◽  
Vol 13 (4) ◽  
pp. 2021
Author(s):  
Vlado Popović ◽  
Milorad Kilibarda ◽  
Milan Andrejić ◽  
Borut Jereb ◽  
Dejan Dragan

Sustainable engineering is very important for logistics systems. Nowadays, sustainable warehouse management is a key factor in market success. Workforce fluctuation and inverting the number of customers’ demands make a lot of problems in distribution warehouses. This study addresses a sustainable approach for the workforce scheduling problem recognized in a real distribution warehouse. The problem arises from the high variability of demand for workers over one workday, which causes workforce surplus in some periods of the workday and shortages in others. Engineering managers of the distribution warehouse already use different full-time and part-time shifts, and schedule workers on different activities, but they still have significant workforce surpluses or shortages in some periods. This study proposes the scheduling of activities’ execution together with workers to face that variability and decrease the cost of the workforce. This idea comes from the fact that some activities in a distribution warehouse can be done in a specific time period after the need for them occurs. In this way, the variability of demand for workers can be decreased, and a lower workforce cost may be ensured. Based on this idea, the entire problem is modeled as integer linear programming. The real example of the problem is solved, and the proposed model is tested on randomly generated instances of the problem in Python by means of the PuLP linear programming package. The results indicate different positive effects in the manner of sustainable warehouse management: lower workforce costs, time savings, better utilization of all types of resources and equipment, increased employee satisfaction, and so on. For even 61% of instances of the introduced problem, the obtained cost of the workforce is lower by more than 20% if activities’ executions are scheduled together with employees.


2021 ◽  
Vol 65 (4) ◽  
pp. 643-651
Author(s):  
Th. Nitschke-Pagel ◽  
J. Hensel

AbstractThe consideration of residual stresses in fatigue-loaded welds is currently done only qualitatively without reliable knowledge about their real distribution, amount and prefix. Therefore, the tools which enable a more or less unsafe consideration in design concepts are mainly based on unsafe experiences and doubtful assumptions. Since the use of explicitly determined residual stresses outside the welding community is state of the art, the target of the presented paper is to show a practicable way for an enhanced consideration of residual stresses in the current design tools. This is not only limited on residual stresses induced by welding, but also on post-weld treatment processes like HFMI or shot peening. Results of extended experiments with longitudinal fillet welds and butt welds of low and high strength steels evidently show that an improved use of residual stresses in fatigue strength approximation enables a better evaluation of peening processes as well as of material adjusted welding procedures or post-weld stress relief treatments. The concept shows that it is generally possible to overcome the existing extremely conservative but although unsafe rules and regulations and may also enable the improved use of high strength steels.


10.1068/c21m ◽  
2002 ◽  
Vol 20 (5) ◽  
pp. 655-677 ◽  
Author(s):  
Carlos Gil ◽  
Pedro Pascual ◽  
Manuel Rapún

Economic disparities among the regions of the European Union are more pronounced than among countries. Structural Funds have played a crucial compensatory role, promoting the economic development and real convergence of lagging regions. The amount of resources destined to regional policy and the conflicts arising from its funding and distribution create the need for an adequate theoretical foundation or model to help politicians solve the distribution problem. In this paper we propose an empirical procedure to carry out and evaluate different distributions of funds for the periods 1989 – 93 and 1994 – 99. We begin with the estimation of an augmented production function to permit the calculation of the expected GDP per capita. We then propose a nonlinear programming method to simulate alternative distributions of Structural Funds among Objective 1 regions, based upon two different approaches: equal development, and equal opportunities. For these two approaches we calculate different possibilities, ranging from highly efficient to highly equitable, with the result that we are able to show the ‘frontier’ of optimal distributions. Finally, we evaluate these results and compare them with the real distribution.


2013 ◽  
Vol 341-342 ◽  
pp. 1363-1366
Author(s):  
Lang Bai ◽  
Le Yu

The evaluation results of power system are greatly influenced by the reliability parameters and uncertainty of system components. The connection number assessment model and an approach have been presented to assess the occurrence frequency due to voltage sags. The proposed method had been applied to a real distribution system. Compared with the interval number method, the simulation results have shown that this method is simple and flexible.


Author(s):  
Niklas Sapountzoglou ◽  
Petra Wittbold ◽  
Aleksandra Zimmermann

2016 ◽  
Vol 8 (6) ◽  
pp. 58
Author(s):  
L. Ndiaye ◽  
Mb. Ndiaye ◽  
A. Sy ◽  
D. Seck

In this paper, we use mass transportation theory to study pollution  transfer in  porous media.  We show   the existence of a $L^2-$regular vector field defined by a $W^{1, 1}-$ optimal transport map. A sufficient condition for solvability of our model, is given by   a (non homogeneous) transport equation with  a  source defined by a measure. The mathematical framework used, allows us to  show in some specifical cases, existence of solution for  a nonlinear PDE deriving from the modelling. And we end by numerical simulations.


Sign in / Sign up

Export Citation Format

Share Document