677 research outputs found

    Ranking irrigation schemes based on principle component analysis in the arid regions of Turkey

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    ArticleWater is a scarce resource and thus irrigation schemes in arid regions have become more important. The irrigation sector which uses most of the water resources has to cope with global warming, disasters and water scarcity around the world, particularly in the Mediterranean countries, including Turkey. Irrigation schemes, which were built by DSI (State Hydraulic Works) and whose operation and maintenance management was transferred to water user associations, play a crucial role in irrigated agriculture in Turkey. In order to improve the performance, weakness and strengths of irrigation schemes are determined by performance indicators (system operation, financial and production efficiency) which show the overall information about them. In the present study, seven irrigation schemes located in an arid region of central Anatolia were chosen to assess the irrigation performance using principal component, correlation and cluster analysis while quality index showed the rank of the irrigation schemes. We found that the average total annual volume of irrigation supply was 7648.58 m3 ha−1 and the average relative water supply was 1.91 during the 11 years between 2006 and 2016. In this region, higher inverse correlations were due to using surface irrigation methods (51.3%). As of 2017, the irrigation schemes have weak water distribution systems, on an average, consisting of 55.5% open canals, 22.5% canalette and only 10% pipes. According to the quality index, financial and system operation indicators are more effective than that of production efficiency indicators. In conclusion, average irrigation ratio (55.68%) can be increased by improving the water distribution system, and the technology used on both management and farm levels

    Mapping performance of irrigation schemes in Turkey

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    Water is a crucial resource and approximately 70% usage of it in the agriculture sector in Turkey. Water user associations are in charge of irrigation water management. The core aim of this study is to assess water user associations have command area more than 1,000 ha (WUAs) within the districts of DSI (State Hydraulic Works) and to create spatial maps to show the distribution of the performance indicators used constantly by researchers especially around Mediterranean countries during the period from 2011 to 2015. Frequency and panel data analysis are used to figure out the relationship among performance indicators and attributes such as water diversion type, management type, source of water and district no. Panel data analysis was applied to examine statistical assessment over time. As a result, current performance indicators show that excessive irrigation water used due to low technology and management problem. Performance indicators show high differences among districts due to climate, water resources, and crop pattern. Moreover, low irrigation efficiency can be increased with a transition to pressurized irrigation systems, so more are can be irrigated with less water

    Weatherability and Leach Resistance of Wood Impregnated with Nano-Zinc Oxide

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    Southern pine specimens vacuum-treated with nano-zinc oxide (nano-ZnO) dispersions were evaluated for leach resistance and UV protection. Virtually, no leaching occurred in any of the nano-ZnO–treated specimens in a laboratory leach test, even at the highest retention of 13 kg/m3. However, specimens treated with high concentrations of nano-ZnO showed 58–65% chemical depletion after 12 months of outdoor exposure. Protection from UV damage after 12 months exposure is visibly obvious on both exposed and unexposed surfaces compared to untreated controls. Graying was markedly diminished, although checking occurred in all specimens. Nano-zinc oxide treatment at a concentration of 2.5% or greater provided substantial resistance to water absorption following 12 months of outdoor exposure compared to untreated and unweathered southern pine. We conclude that nano-zinc oxide can be utilized in new wood preservative formulations to impart resistance to leaching, water absorption and UV damage of wood

    Archaea catalyze iron-dependent anaerobic oxidation of methane

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    Anaerobic oxidation of methane (AOM) is crucial for controlling the emission of this potent greenhouse gas to the atmosphere. Nitrite-, nitrate-, and sulfate-dependent methane oxidation is well-documented, but AOM coupled to the reduction of oxidized metals has so far been demonstrated only in environmental samples. Here, using a freshwater enrichment culture, we show that archaea of the order Methanosarcinales, related to “Candidatus Methanoperedens nitroreducens,” couple the reduction of environmentally relevant forms of Fe^(3+) and Mn^(4+) to the oxidation of methane. We obtained an enrichment culture of these archaea under anaerobic, nitrate-reducing conditions with a continuous supply of methane. Via batch incubations using [^(13)C]methane, we demonstrated that soluble ferric iron (Fe^(3+), as Fe-citrate) and nanoparticulate forms of Fe^(3+) and Mn^(4+) supported methane-oxidizing activity. CO_2 and ferrous iron (Fe^(2+)) were produced in stoichiometric amounts. Our study connects the previous finding of iron-dependent AOM to microorganisms detected in numerous habitats worldwide. Consequently, it enables a better understanding of the interaction between the biogeochemical cycles of iron and methane

    Smart Cities: Towards a New Citizenship Regime? A Discourse Analysis of the British Smart City Standard

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    Growing practice interest in smart cities has led to calls for a less technology-oriented and more citizen-centric approach. In response, this articles investigates the citizenship mode promulgated by the smart city standard of the British Standards Institution. The analysis uses the concept of citizenship regime and a mixture of quantitative and qualitative methods to discern key discursive frames defining the smart city and the particular citizenship dimensions brought into play. The results confirm an explicit citizenship rationale guiding the smart city (standard), although this displays some substantive shortcomings and contradictions. The article concludes with recommendations for both further theory and practice development

    Residual stress measurement round robin on an electron beam welded joint between austenitic stainless steel 316L(N) and ferritic steel P91

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    This paper is a research output of DMW-Creep project which is part of a national UK programme through the RCUK Energy programme and India's Department of Atomic Energy. The research is focussed on understanding the characteristics of welded joints between austenitic stainless steel and ferritic steel that are widely used in many nuclear power generating plants and petrochemical industries as well as conventional coal and gas-fired power systems. The members of the DMW-Creep project have under- taken parallel round robin activities measuring the residual stresses generated by a dissimilar metal weld (DMW) between AISI 316L(N) austenitic stainless steel and P91 ferritic-martensitic steel. Electron beam (EB) welding was employed to produce a single bead weld on a plate specimen and an additional smoothing pass (known cosmetic pass) was then introduced using a defocused beam. The welding re- sidual stresses have been measured by five experimental methods including (I) neutron diffraction (ND), (II) X-Ray diffraction (XRD), (III) contour method (CM), (IV) incremental deep hole drilling (iDHD) and (V) incremental centre hole drilling (iCHD). The round robin measurements of weld residual stresses are compared in order to characterise surface and sub-surface residual stresses comprehensively

    Comparative analysis of the semileptonic ΛbΛ+\Lambda_b \rightarrow \Lambda \ell^+ \ell^- transition in SM and different SUSY scenarios using form factors from full QCD

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    We work out the semileptonic ΛbΛ+\Lambda_b\rightarrow \Lambda \ell^+ \ell^- transition in standard as well as different supersymmetric models. In particular, considering the parametrization of the matrix elements entered the low energy effective Hamiltonian in terms of form factors in full QCD, we calculate the amplitude and differential decay rate responsible for this decay channel in supersymmetric models. We then use the form factors calculated via light cone QCD sum rules in full theory to analyze the differential branching ratio and lepton forward-backward asymmetry of this decay channel in different supersymmetric models and compare the obtained results with those of the standard model. We also discuss how the results of different supersymmetric models deviate from the standard model predictions and which SUSY scenarios are favored.Comment: 23 Pages, 8 Figures and 11 Table

    Constraints on instantaneous ozone production rates and regimes during DOMINO derived using in-situ OH reactivity measurements

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    In this study air masses are characterized in terms of their total OH reactivity which is a robust measure of the reactive air pollutant loading . The measurements were performed during the DOMINO campaign (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) held from 21/11/2008 to 08/12/2008 at the Atmospheric Sounding Station - El Arenosillo (37.1° N-6.7° W, 40 m a.s.l.). The site was frequently impacted by marine air masses (arriving at the site from the southerly sector) and air masses from the cities of Huelva (located NW of the site), Seville and Madrid (located NNE of the site). OH reactivity values showed strong wind sector dependence. North eastern continental air masses were characterized by the highest OH reactivities (average: 31.4 ± 4.5 s−1; range of average diel values: 21.3-40.5 s−1), followed by north western industrial air masses (average: 13.8 ± 4.4 s−1; range of average diel values: 7-23.4 s−1) and marine air masses (average: 6.3 ± 6.6 s−1; range of average diel values: below detection limit −21.7 s−1), respectively. The average OH reactivity for the entire campaign period was ~18 s−1 and no pronounced variation was discernible in the diel profiles with the exception of relatively high values from 09:00 to 11:00 UTC on occasions when air masses arrived from the north western and southern wind sectors. The measured OH reactivity was used to constrain both diel instantaneous ozone production potential rates and regimes. Gross ozone production rates at the site were generally limited by the availability of NOx with peak values of around 20 ppbV O3 h−1. Using the OH reactivity based approach, derived ozone production rates indicate that if NOx would no longer be the limiting factor in air masses arriving from the continental north eastern sector, peak ozone production rates could double. We suggest that the new combined approach of in-situ fast measurements of OH reactivity, nitrogen oxides and peroxy radicals for constraining instantaneous ozone production rates, could significantly improve analyses of upwind point sources and their impact on regional ozone levels
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