Search results for "RILL"

'Le lacrime del coccodrillo'

2008

Testing flow resistance equation for rill flow

2018

At first, in this paper a flow resistance equation for rill flow, deduced applying dimensional analysis and self-similarity theory, is presented. The incomplete self-similarity hypothesis is used for establishing the flow velocity distribution whose integration gives the theoretical expression of the Darcy-Weisbach friction factor. Then the deduced theoretical resistance equation, which is calibrated by some measurements of flow velocity, water depth, cross section area, wetted perimeter and bed slope carried out in 106 reaches of some rills modelled on an experimental plot, is tested using the literature data by Abrahams et al. (1996), Strohmeier et al. (2014) and Peng et al. (2015) for ri…

Effetto del flusso elongazionale sulle proprietà e sulla morfologia di filamenti di nanocomposito a base di polietilene e montmorillonite organo-modi…

2008

Pembesaran Ikan Nila (Oreochromis niloticus) pada Budidaya Sistem Resirkulasi Menggunakan Filtrasi Tanaman Hydrilla verticillata dan Ceratophyllum de…

2021

Penelitian ini mengkombinasikan tanaman Hydrilla verticillata dengan Ceratophyllum demersum sebagai filter pada budidaya ikan Nila sistem resirkulasi. Tujuan penelitian yaitu untuk mengetahui tingkat pertumbuhan ikan Nila pada budidaya sistem resirkulasi. Filtrasi yang digunakan pada budidaya sistem resirkulasi yaitu tanaman H. verticillata dan C. demersum. Metode penelitian menggunakan rancangan acak lengkap (RAL). Adapun parameter yang diamati berupa kelangsungan hidup ikan, pertumbuhan mutlak, laju pertumbuhan spesifik (SGR), Feed Conversion Ratio (FCR) dan kualitas air. Kelangsungan hidup ikan selamat pemeliharaan yaitu 100%. Pertumbuhan bobot mutlak individu berkisar 8.76 sampai 16.6 g…

ESPERIMENTO DI SIMULAZIONE DELLA FORMAZIONE DEI RILL A SCALA DI PARCELLA

2016

Nella memoria sono riportati i risultati di un esperimento di simulazione della formazione del canale di un rill condotto in una parcella avente una dimensione 2x7 m2 ed una pendenza del 14% realizzata dal Dipartimento di Scienze Agrarie e Forestali dell’Università di Palermo. Una rete di solchi, costituita da due canali principali, è stata, dapprima incisa sul suolo manualmente e successivamente modellata utilizzando una corrente idrica limpida. Sui solchi modellati è stato effettuato, in corrispondenza di 11 sezioni trasversali della parcella, il rilievo delle caratteristiche geometriche e idrauliche utilizzando un profilometro. L’indagine ha inoltre previsto la realizzazione sia di un mo…

Assessing dye-tracer technique for rill flow velocity measurements

2018

Abstract Rill erosion is considered one of the most important processes affecting soil because of the large amount of soil loss. The rill network acts as sediment source and is able to transport both rill flow-detached particles and those delivered from the interrill areas. Small flow depth in a rill and steep slope values of its bed affect significantly flow hydraulics. When rill flow velocity is measured using a dye-tracing method, the mean velocity is calculated by multiplying the measured surface velocity of the leading edge of the tracer plume by a correction factor. The main uncertainty of the dye-tracing technique stands in the relationship between mean and surface flow velocity. In …

The role of hydrochlorofluorocarbon densifiers in the formation of clathrate hydrates in deep boreholes and subglacial environments

2007

AbstractClear evidence for the formation of mixed clathrate hydrates of air and hydrochlorofluorocarbon densifier (known as HCFC-141b, sometimes also called R-141b) is found by means of synchrotron X-ray diffraction and Raman spectroscopy on a sample recovered from the bottom of the EPICA Dronning Maud Land deep borehole in Antarctica. Subglacial water (SGW) appears to have reacted with the drilling liquid to build a large lump of clathrate hydrate. The hydrate growth may well have been accelerated by the stirring of the SGW–densifier mixture during drilling. Moreover, dissolved air in the SGW appears to have participated in the formation of mixed hydrates of air and HCFC-141b as evidenced …

2015

Large volcanic eruptions are major geohazards, so identifying their frequency in the geologic record is critical for making predictions and hazard assessments. Following the discovery of a thick (18 cm) tephra layer in marine sediments from Integrated Ocean Drilling Program (IODP) Site U1396 between Montserrat and Guadeloupe in the Caribbean Sea, we document here how high-precision Pb isotopes, trace elements, and grain morphological analyses of the tephra can be used, together with volcanological models, to identify a large (Volcanic Explosivity Index ?6) Plinian eruption from Basse-Terre, Guadeloupe, at ca. 2.36 Ma. This previously unrecognized eruption is believed to be the largest docum…

Comment on “Effects of different tillage practices on the hydraulic resistance of concentrated flow on the loess plateau in China” by J. Sun et al

2020

Abstract For concentrated flows, which are characterized by small water depth and steep sloping beds, hydraulic conditions different from those typical of streams and rivers occur. In this study a new theoretically deduced flow resistance equation was tested using the experimental data by Sun et al. for three different tilled surfaces (Manual Dibbling, MD, Manual Hoeing, MH, and Contour Drilling, CD). At first, the profile parameter-relationship, which is the relationship between the velocity profile parameter Γ, the channel slope and the flow Froude number, was calibrated using rill flow data by Di Stefano et al. Then, the applicability of this relationship was tested by the measurements o…

Uso del método mejorado del uso del injerto (Isum) como herramienta para determinar el valor de factores topográficos alternativos en la estimación d…

2020

Made available in DSpace on 2020-12-12T02:01:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-15 The Improved Stock Unearthing Method (ISUM) was initially designed to assess soil mobilisation rates in vineyards; however, other grafted crops such as citrus orchards could also be successfully used. The results obtained from ISUM have been used for several goals, but have not yet been applied for computing the LS factor (length and slope) as a part of the Universal Soil Loss Equation (USLE), which could give useful information to improve soil management system plans. This investigation was conducted in an 8-year old clementine field located in Canals (Valencia, Spain) and values of…