Search results for "forest"
showing 10 items of 3780 documents
Predicting soil loss on moderate slopes using an empirical model for sediment concentration
2011
Summary The objective of this investigation was to estimate event soil loss per unit area from bare plots in central and southern Italy using an empirical model for sediment concentration. The analysis was developed using data collected on bare plots differing in length (11–44 m) and slope (10–26%) at three Italian stations (Masse, Umbria; Caratozzolo, Calabria; Sparacia, Sicily). At first, an analysis was carried out, using the experimental data collected at Sparacia, to establish a relationship between sediment concentration and hydrological variables, such as runoff, rainfall amount and single storm erosion index. Then, an empirical model to estimate plot soil loss as a function of rainf…
A new expression of the slope length factor to apply USLE-MM at Sparacia experimental area (Southern Italy)
2013
Abstract Predicting soil loss due to water erosion by empirical models is useful to assess the severity of the phenomenon in an area of interest and to predict the effect of alternative soil erosion control practices. The USLE scheme cannot be used at the Sparacia experimental area (Sicily, South Italy) to predict event soil loss per unit plot area, Ae, because experimental data suggest that, generally, Ae does not increase with plot length, λ. The USLE-MM scheme uses the runoff coefficient, QR, as an additional independent variable in order to develop an empirical model allowing prediction of storm soil loss values that do not necessarily increase with λ. According to this model, Ae is exp…
Advances in designing drip irrigation laterals
2018
It is known that using paired laterals, in which two distribution pipes extend in opposite directions from a common manifold, contribute to increasing water use efficiency (WUE). Recently, an analytical procedure to optimally design paired drip laterals on uniform slopes was proposed. More recently, this design procedure was simplified by deriving simple explicit relationships, as a function of 16 calibration constants, with relative errors that were less than 2%. In this paper, further simple design relationships are derived that require only 3 calibration constants, thus more readily obtainable results are produced and the influence of the flow rate and diameter exponents of resistance eq…
Sequent Depth Ratio of a B-Jump
2011
A B-jump is defined as the jump having the toe section located on a positively sloping upstream channel and the roller end on a downstream horizontal channel. This jump often occurs in the stilling basins with a horizontal bottom and located downstream of a steep channel. For a B-jump, a completely theoretical approach is not sufficient to solve the momentum equation and to establish the sequent depth ratio. In this paper, by using the laboratory measurements carried out in this investigation, some available empirical relationships useful for estimating the sequent depth ratio are tested. Then, by using the Π theorem of the dimensional analysis and the incomplete self-similarity theory, a g…
Contrasting Norway spruce disturbance dynamics in managed forests and strict forest reserves in Slovakia
2022
Abstract Forest disturbances are intensifying globally, yet regional drivers of these dynamics remain poorly understood. We investigated recent disturbance intensities in Norway spruce (Picea abies L.) forests in Slovakia (Central Europe) with different management objectives in 2000–2017 based on Landsat imagery. We focused on 122 strict reserves without any management, their actively managed surroundings (500 m and 2000 m buffers), and managed production forests beyond the buffer areas. We used generalized additive mixed models to test for differences in temporal trends of disturbance intensity among these management categories. We found that disturbance intensity was increasing in all man…
New-stage discharge relationships for free and submerged sluice gates
2012
Abstract The flow movement through a sluice gate is investigated for both free and submerged flow conditions. For free flow condition, the current dimensionless formula, indicated acceptable accuracy; while for submerged flow condition it was modified especially for low submerged condition. In this regard, Buckingham theorem along with the Incomplete Self-Similarity concept was employed and a new stage–discharge relationship was developed accordingly. Also, to achieve a suitable formula for submerged flow condition being accurate in low submergence, the maximum tailwater depth allowing the free flow condition and head loss factor were identified as missing parameters in the functional dimen…
New stage-discharge relationship for cylindrical and semi-cylindrical edged sluice gates
2019
Abstract Gates are simple hydraulic structures which have been widely used for flow control and measurement in irrigation networks. In this paper new sluice gates with cylindrical and semi-cylindrical edges were introduced and the flow movement below these types of gates was experimentally investigated for both free- and submerged-flow conditions. The Buckingham theorem of dimensional analysis and the self-similarity theory were applied for developing the stage-discharge relationships for the two investigated flow conditions. For these cylindrical and semi-cylindrical edged gates and a free-flow condition, the proposed stage-discharge relationship was characterized by an estimate error less…
Social media e pubblica amministrazione. Una rassegna
2015
Negli ultimi vent’anni i processi di cambiamento strutturale a cui sono state indotte – o, in altri casi, a cui si sono strategicamente dedicate - le organizzazioni sono stati molteplici. Cause fra le più diverse hanno determinato, più o meno direttamente, effet-ti di ricombinazione delle funzioni interne alle stesse organizzazioni da parte degli atto-ri che le popolano, ovvero di una vera e propria nuova strutturazione, in ragione di mutate caratteristiche dell’ambiente in cui esse operano, di mutati e più stringenti vin-coli economici dentro i quali muoversi rispetto al passato anche recente e, nel caso di quelle che producono beni o servizi direttamente destinati ad una clientela o ad un…
Whose Narrative is it Anyway? Narratives of Social Innovation in Rural Areas – A Comparative Analysis of Community‐Led Initiatives in Scotland and Sp…
2020
Social innovation is a process in which local communities build social and cultural capital to address challenges and social needs. The diffusion of social innovation requires compelling narratives that encourage people to join them. Using qualitative techniques and a multiple case study methodology, this paper examines the content of narratives of social innovation in rural areas and how actors construct, spread and change them. We propose a narrative analytical framework comprising four key components: problematisation; solutions and goals; actors; and plot, which we apply to three initiatives in Scotland and Spain. Our findings suggest that marginalisation, the natural environment and co…
Imagining Africa and blackness in the Russian empire: from extra-textualarapkaand distant cannibals to Dahomey amazon shows – live in Moscow and Riga
2013
In the nineteenth century, Dahomey amazon shows, traveling circuses with menageries and ‘African villages,’ emerged as part of the transnational entertainment industry. This article extends the geography of this global model and generic system and its role in the visual politics of whiteness and blackness in a context outside the imperial colonization of Africa. The first sections examine a rise of visuality in the Russian imperial imagination of race, Africa and blackness through a ‘symptomatic’ reading of Aleksandr Griboedov's play Woe from Wit and Arkadii Averchenko's Death of an African Hunter. These are followed by a discussion of the Dahomey amazon shows in Moscow and their significan…