Search results for "flow [Keywords]"

Flow resistance of overland flow on a smooth bed under simulated rainfall

2020

In this paper a recently theoretically deduced flow resistance equation, based on a power-velocity profile, was tested using laboratory measurements by Yoon and Wenzel for an overland flow on a smooth bed under rainfall. These measurements of the Darcy-Weisbach friction factor, corresponding to a wide range of the flow Reynolds number (191–5700), were carried out for an overland flow under a simulated rainfall characterized by different intensity values ranging from 13 to 381 mm h−1. At first, the available measured values of flow velocity, water depth, cross sectional area, wetted perimeter and bed slope were used to calibrate the relationship between the velocity profile parameter Γ, the …

Two Job Cyclic Scheduling with Incompatibility Constraints

2001

The present paper deals with the problem of scheduling several repeated occurrences of two jobs over a finite or infinite time horizon in order to maximize the yielded profit. The constraints of the problem are the incompatibilities between some pairs of tasks which require a same resource.

HEURISTIC PROCEDURES FOR GROUP SCHEDULING

1989

ABSTRACT The group scheduling problem is investigated, solving numerous small and large sized examples with eight sequencing algorithms. A new approach, basically consisting in the definition of real machines' idles for each group, utilizing allowed shifting of non critical activities, is proposed. Moreover the CDS multi-shot algorithm is extended to group scheduling.

Investigating diffuse CO2 degassing in tectonically active areas by groundwater

Flow velocity profile and turbulence characteristics in a vegetated straight flume

2008

Vegetation affects the hydrodynamic conditions of an open channel flow with direct implications in physical and biophysical processes. In this paper, the vertical flow velocity distribution of a vegetated flow has been analyzed using experimental data collected in a straight flume. The experimental velocity distributions are positively compared with the hyperbolic tangent profile of a pure mixing layer previously verified by Ghisalberti and Nepf (2002). Peculiarly, for different flow and vegetative conditions, fitting of the hyperbolic tangent profile to the experimental velocity distributions has allowed the localization of the inflection point of the velocity profile at a distance from th…

Evaluation of the effect of transcutaneous electrical nerve stimulation (TENS) on whole salivary flow rate

2015

Background: Saliva plays a critical role in maintaining oral homeostasis; it modulates the ecosystem through lubrication of the alimentary bolus, protection against microorganisms, buffer and repair of the oral mucosa, and helps in dental re-mineralization. Various local and systemic factors such as medications, radiation therapy, systemic conditions, etc. can lead to reduction in salivary flow. A decrease in salivary function, known as Xerostomia, increases a patient's risk for caries and other oral infections. Palliative management of Xerostomia includes wetting agents such as ice chips, drugs and saliva substitutes. Systemic agents stimulate salivary flow but often have unfavorable side …

Stimulated whole salivary flow rate: The most appropriate technique for assessing salivary flow in Sjogren syndrome

2020

Background We sought to determine the most appropriate method for measuring salivary flow to aid the diagnosis of Sjögren's syndrome (SS). Specifically, we compared the unstimulated whole salivary flow rate (UWSFR) with the stimulated whole salivary flow rate (SWSFR). Material and Methods This case-control study comprised one group of 103 patients with SS and a control group of 50 healthy people. We measured the UWSFR and SWSFR in both groups according to the guidelines established by Navacet (1993). Results The UWSFR and SWSFR were significantly lower in the patient group compared with the controls (p < 0.01). Among the participants in the patient group, we found a decreased UWSFR in 84 in…

Dissipative scaling of step-pool features

2021

Abstract This paper focuses on the dissipative similarity of step-pool units at rill, flume and stream scale. This investigation is carried out using recent advances in open channel flow resistance, applications of close-range photogrammetry to rill erosion, available published data on step-pool features in flumes and streams and a new dataset of measurements in fixed bed step-pool rills. A theoretically-based equation for calculating the Darcy-Weisbach friction factor obtained by integration of a power velocity profile is presented. The scale factor Γ of this power velocity profile, which is included in the flow resistance equation, was previously calibrated (Eq. 10) for mobile bed rills w…

The apparent losses due to metering errors: a proactive approach to predict losses and schedule maintenance

2014

The effects of water meter age and private tanks on the apparent losses due to metering errors were evaluated by experimental and theoretical analyses. A monitoring campaign on a small district metered area (DMA) was carried out to determine the causes of apparent losses and implement a numerical model. Metering errors are affected by the flow rate passing through the meter, which is dependent on the network pressure and water level of the private tank. A node model that reproduces the effect of private tanks was coupled with EPANET and was applied to the DMA. The proposed modelling approach was used to identify where apparent losses are higher and to schedule maintenance. The model predict…

The use of constructed wetlands for the treatment and reuse of urban wastewater for the irrigation of two warm-season turfgrass species under Mediter…

2017

Constructed wetlands (CWs) represent low-cost technology for the treatment and reuse of wastewater in urban areas. This study aimed to evaluate the pollutant removal efficiency of a CW system and to assess the effects of irrigation using treated urban wastewater on soil and on two warm-season turf species. The research was carried out in Sicily (Italy) on a pilot-scale horizontal subsurface flow system which was fed with treated urban wastewater following secondary treatment from an activated-sludge wastewater treatment plant. The pilot system was located in an open urban park and comprised two separate parallel planted units. Experimental fields of Cynodon dactylon (L.) Pers. and Paspalum …