1,768 research outputs found
Managing Surged Furrow Irrigation
The behaviour of the infiltration process in an irrigation system is the most important feature that must be determined. Knowledge of soil infiltration,
as it is a dominant physical process in surface irrigation, is crucial to the successful implementation of the scheme. This cannot be over-emphasized in surface systems, especially in furrow systems. This paper describes the infiltration behaviour of a furrow irrigation system under the surge flow regime. Infiltration behaviour over the various runs was studied, Suggestions for the implementation of such a management-oriented
irrigation practice are discussed. The infiltration characteristics over the various flows are given
The optical properties of InGaAs(P)/InP under group V sublattice two-phase interdiffusion
Using the fundamental transition state, we will investigate the two phase interdiffusion of group V sublattice in a strained lattice matched InGaAs/InP quantum well (QW) structures. The model employs three parameters namely the diffusion coefficients in the barrier (Db)and in the well (Dw)and the concentration ratio (k) of the diffused species at the heterstructure. The QW model includes the effects of strain and the exciton. A pseudo time dependent calculation is also considered and results are fitted to the reported experimental data. These parameters which characterize the diffusion mechanism can be measure to form a better understanding of the interdiffsion process for group V sublattice.published_or_final_versio
Holographic phase transition in a non-critical holographic model
We consider a holographic model constructed from the intersecting brane
configuration D4-/D4 in noncritical string theory. We study the
chiral phase diagram of this holographic QCD-like model with a finite baryon
chemical potential through the supergravity dual approximation.Comment: 14 pages, reference adde
Load balance algorithms for anycast
Increasingly, replicated anycast servers are being used to deliver network applications and service ever increasing user requests. Therefore, the strategies used to guarantee network bandwidth prerequisites and perform load balancing across the nodes of an anycast group are critical to the performance of online applications. In this paper, we model user requests, network congestion and latency, and server load using a combination of hydro-dynamics and queuing theory to develop an efficient job distribution strategy. Current, anycast research does not explicitly consider the system load of nodes within an anycast groups when distributing requests. Therefore, the performance of a heavily loaded anycast system can quickly become congested and uneven as jobs are routed to closely linked nodes which are already saturated with requests. In comparison, the nodes of further away systems remain relatively unused because of other issues such as network bandwidth and latency during these times. Our system redirects requests from busy systems to the idle, remotely linked nodes, to process requests faster in spite of slower network access. Using an empirical study, we show this technique can improve request performance, and throughput with minimal network probing overhead.<br /
Intraocular oxygen and antioxidant status: New insights on the effect of vitrectomy and glaucoma pathogenesis
PURPOSE: The purpose of this study was to investigate correlations of partial pressure of oxygen (pO
METHODS: This prospective, cross-sectional study stratified patients (n = 288 eyes) by lens and vitreous status and the presence of primary open-angle glaucoma for statistical analyses. Intraocular pO
RESULTS: Following prior pars plana vitrectomy, pO
CONCLUSIONS: Increased p
A Note on Chiral Symmetry Breaking from Intersecting Branes
In this paper, we will consider the chiral symmetry breaking in the
holographic model constructed from the intersecting brane configuration, and
investigate the Nambu-Goldstone bosons associated with this symmetry breaking.Comment: 16 pp, minor changes, to appear PR
A multiple type bike repositioning problem
This paper investigates a new static bicycle repositioning problem in which multiple types of bikes are considered. Some types of bikes that are in short supply at a station can be substituted by other types, whereas some types of bikes can occupy the spaces of other types in the vehicle during repositioning. These activities provide two new strategies, substitution and occupancy, which are examined in this paper. The problem is formulated as a mixed-integer linear programming problem to minimize the total cost, which consists of the route travel cost, penalties due to unmet demand, and penalties associated with the substitution and occupancy strategies. A combined hybrid genetic algorithm is proposed to solve this problem. This solution algorithm consists of (i) a modified version of a hybrid genetic search with adaptive diversity control to determine routing decisions and (ii) a proposed greedy heuristic to determine the loading and unloading instructions at each visited station and the substitution and occupancy strategies. The results show that the proposed method can provide high-quality solutions with short computing times. Using small examples, this paper also reveals problem properties and repositioning strategies in bike sharing systems with multiple types of bikes.published_or_final_versio
Investigation of passive flow control techniques to enhance the stall characteristics of a microlight aircraft
This report investigates the enhancement of aerodynamic stall characteristics of a Skyranger microlight aircraft by the use of passive flow control techniques, namely vortex generators and turbulators. Each flow control device is designed and scaled to application conditions. Force balance measurements and surface oil flow visualisation are carried out on a half-model of the microlight to further investigate the nature of the flow on the aircraft with and without the flow control devices. The results indicate a clear advantage to the use of turbulators compared with vortex generators. Turbulators increased the maximum lift coefficient by 2.8%, delayed the onset of stall by increasing the critical angle by 17.6% and reduced the drag penalty at both lower (pre-stall) and higher angles of attack by 8% compared to vortex generators. With vortex generators applied, the results indicated a delayed stall with an increase in the critical angle by 2% and a reduced drag penalty at higher angles of attack
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