679,144 research outputs found

    Pengaruh Sudu - Sudu pada Model Kincir Air Undershot untuk Irigasi Pertanian

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    Undershot water wheel is appropriate technologies that raise the water level elevation of the river which was originally low for irrigation purposes with low cost. The water wheel is generally used in agricultural areas that do not get technical irrigation network. Water capacity capable be appointed the waterwheel is relatively low when compared with technical irrigation but the capacity could be increased if the factors affecting debits lifter of water can be optimized. These factors are the blades, the debit of flow, the position of box, the amount and type of box. The purpose of the research determines the dimensions of blade effective and debit of flow optimum which produces a maximum of debits lifter water. Research conducted in the laboratory to do the testing on the model undershot waterwheel. Model waterwheel was created in such a manner resembling a waterwheel in the field without scale models. Testing is done by varying the dimensions of the blade is the blade size of 6 cm × 4.5 cm, 6 cm × 6 cm and 6 cm × 7.5 cm, and then the flow rate is 3.07 l / sec, 3.8 l / sec and 5,99 l / sec and amount of box is 6, 12, 18, 24, 30 and 36 as well as the type of box that is type 1 (small size), type 2 (medium size) and type 3 (large size). The results showed the number of boxes 36 with a box type 3 in spoon size of 6 cm × 6 cm to debit of flow 5,99 l / sec produce maximum of debits lifter water that is equal to 38,17 ml /sec. It can be concluded dimention of spoon effective is the size of 6 cm × 6 cm and debit of flow that optimum is 5,99 l / sec

    The Dynamics of Internet Traffic: Self-Similarity, Self-Organization, and Complex Phenomena

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    The Internet is the most complex system ever created in human history. Therefore, its dynamics and traffic unsurprisingly take on a rich variety of complex dynamics, self-organization, and other phenomena that have been researched for years. This paper is a review of the complex dynamics of Internet traffic. Departing from normal treatises, we will take a view from both the network engineering and physics perspectives showing the strengths and weaknesses as well as insights of both. In addition, many less covered phenomena such as traffic oscillations, large-scale effects of worm traffic, and comparisons of the Internet and biological models will be covered.Comment: 63 pages, 7 figures, 7 tables, submitted to Advances in Complex System

    Distributed flow optimization and cascading effects in weighted complex networks

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    We investigate the effect of a specific edge weighting scheme (kikj)β\sim (k_i k_j)^{\beta} on distributed flow efficiency and robustness to cascading failures in scale-free networks. In particular, we analyze a simple, yet fundamental distributed flow model: current flow in random resistor networks. By the tuning of control parameter β\beta and by considering two general cases of relative node processing capabilities as well as the effect of bandwidth, we show the dependence of transport efficiency upon the correlations between the topology and weights. By studying the severity of cascades for different control parameter β\beta, we find that network resilience to cascading overloads and network throughput is optimal for the same value of β\beta over the range of node capacities and available bandwidth

    A three-dimensional macroscopic fundamental diagram for mixed bi-modal urban networks

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    Recent research has studied the existence and the properties of a macroscopic fundamental diagram (MFD) for large urban networks. The MFD should not be universally expected as high scatter or hysteresis might appear for some type of networks, like heterogeneous networks or freeways. In this paper, we investigate if aggregated relationships can describe the performance of urban bi-modal networks with buses and cars sharing the same road infrastructure and identify how this performance is influenced by the interactions between modes and the effect of bus stops. Based on simulation data, we develop a three-dimensional vehicle MFD (3D-vMFD) relating the accumulation of cars and buses, and the total circulating vehicle flow in the network. This relation experiences low scatter and can be approximated by an exponential-family function. We also propose a parsimonious model to estimate a three-dimensional passenger MFD (3D-pMFD), which provides a different perspective of the flow characteristics in bi-modal networks, by considering that buses carry more passengers. We also show that a constant Bus-Car Unit (BCU) equivalent value cannot describe the influence of buses in the system as congestion develops. We then integrate a partitioning algorithm to cluster the network into a small number of regions with similar mode composition and level of congestion. Our results show that partitioning unveils important traffic properties of flow heterogeneity in the studied network. Interactions between buses and cars are different in the partitioned regions due to higher density of buses. Building on these results, various traffic management strategies in bi-modal multi-region urban networks can then be integrated, such as redistribution of urban space among different modes, perimeter signal control with preferential treatment of buses and bus priority

    A Subtidal Box Model based on the Longitudinal Anomaly of Potential Energy for Narrow Estuaries. An Application to the Guadalquivir River Estuary (SW Spain).

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    The objective of the present study is to demonstrate the informative capacity of the longitudinal anomaly of potential energy (LAPE) in the analysis of the magnitude and spatiotemporal variability of estuarine processes. For this purpose, a LAPE balance equation is formulated. The LAPE integrates and varies with the vertical and longitudinal density distribution. The formulation is applied on a subtidal scale to each box or stretch of the Guadalquivir River estuary, a narrow, highly turbid, weakly stratified, and strongly anthropized estuary. Data recorded by a large network of monitoring stations in 2008 and 2009 are used to quantify advective transports as well as the transports associated with longitudinal dispersion and vertical turbulent mixing in different hydraulic regimes. In low-river flow conditions, (river flows Q < 40m3s−1), the magnitude of LAPE transports decreases upstream and varies locally, depending on neap-spring tidal cycles. The direction of the net LAPE transport creates convergence zones that are particularly consistent with maximum levels of estuarine turbidity. During high-river flows (Q > 400m3s−1), this convergence disappears and the maximum longitudinal density gradient moves towards the mouth. More specifically, tidal pumping -induced LAPE governs during these conditions and manages to compensate the sum of the mean nontidal and dispersive and differential advective LAPE transports. However, during the postriverflood period, the mechanisms controlling recovery downstream from the mouth are the longitudinal dispersive and differential advective LAPE transports. Furthermore, the convergence zone reappears with a longitudinal gradient of the net LAPE transport that is even greater than in low-river flow conditions.This research was partially funded by the Campus de Excelencia Internacional del Mar (Cei-MAR) and the Spanish Ministry of Economy and Competitiveness, Project PIRATES (CTM2017-89531-R). It was also supported by AQUACLEW. Project AQUACLEW is part of ERA4CS, an ERA- NET initiated by JPI Climate, and funded by FORMAS (SE), DLR (DE), BMWFW (AT), IFD (DK), MINECO (ES), ANR (FR) with co-funding by the European Commission.We would like to thank two anonymous reviewers for the thoughtful contribution that has signicantly improved the quality of the paper. Datasets for this research are available in http://doi.org/10.5281/ zenodo.3459610. This study is a tribute to the memory of RichardW. Garvine, whose research was the inspiration for our work
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