465 research outputs found

    Distribuição espacial da pressão na lateral de um pivô central com base em um modelo digital de elevação (MDE)

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    The spatial distribution of pressure head values along a 432,6m long center pivot lateral line was determined using measured values, taken at the inlet and end sections of the lateral line, and combined with topographic elevation data from a SRTM (Shuttle Radar Topography Mission) image. Data furnished by SRTM describes topographic elevation values along the wheel tracks of each one of the eight towers used for the sustentation of the center pivot lateral line. For validation purposes of the process used for the determination of the pressure head distribution along the lateral line length, on 18 angular positions equally spaced along a complete turn of the lateral line, values of pressure head were also measured on 6 distinct points of the lateral line. Differences, on a 5% signiï¬cance level for the student t means test, were observed when measured values were compared to pressure head values estimated based on SRTM's altitude data. After the creation of thematic maps, there was a coincidence in the positioning of the regions of occurrence of the highest of pressure head, also, the lower pressure head values. The study demonstrates that the use of elevation data from SRTM images is acceptable only for the elaboration of thematic maps destined to delimit within the irrigated area the occurrence of regions where different pressure head values prevailed.A distribuição espacial da carga de pressão ao longo dos 432,6m de comprimento de uma linha lateral de um pivô central foi determinada a partir de valores medidos, na entrada e na extremidade da linha lateral, e combinados com dados de altitude proveniente de uma imagem SRTM do rastro das oito torres de sustentação da linha lateral. Para fins de validação da estimativa da distribuição espacial da carga de pressão na linha lateral móvel, em 18 diferentes posições angulares, foram medidos valores de carga de pressão em seis pontos distintos do seu comprimento. Diferenças significativas, ao nível de 5% do teste de médias “t de student”, foram observadas quando valores de carga de pressão estimados com dados de altitude do SRTM foram comparados com os valores medidos em campo. Após a confecção de mapas temáticos verificou-se coincidência no posicionamento das regiões de ocorrência dos valores mais elevados, como também dos menores valores de carga de pressão. O estudo demonstrou que o uso de dados de elevação a partir de imagens SRTM é aceitável apenas para a elaboração de mapas temáticos destinados a delimitar dentro da área irrigada a ocorrência de regiões onde prevaleceram valores de pressão distintos

    Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

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    Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a ZZ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 <pT<100< p_{\textrm{T}} < 100 GeV and in the pseudorapidity range 2.5<η<42.5 < \eta < 4. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb1^{-1}. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

    Study of the BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

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    The decay BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} is studied in proton-proton collisions at a center-of-mass energy of s=13\sqrt{s}=13 TeV using data corresponding to an integrated luminosity of 5 fb1\mathrm{fb}^{-1} collected by the LHCb experiment. In the Λc+K\Lambda_{c}^+ K^{-} system, the Ξc(2930)0\Xi_{c}(2930)^{0} state observed at the BaBar and Belle experiments is resolved into two narrower states, Ξc(2923)0\Xi_{c}(2923)^{0} and Ξc(2939)0\Xi_{c}(2939)^{0}, whose masses and widths are measured to be m(Ξc(2923)0)=2924.5±0.4±1.1MeV,m(Ξc(2939)0)=2938.5±0.9±2.3MeV,Γ(Ξc(2923)0)=0004.8±0.9±1.5MeV,Γ(Ξc(2939)0)=0011.0±1.9±7.5MeV, m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV}, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Λc+K\Lambda_{c}^{+} K^{-} sample. Evidence of a new Ξc(2880)0\Xi_{c}(2880)^{0} state is found with a local significance of 3.8σ3.8\,\sigma, whose mass and width are measured to be 2881.8±3.1±8.5MeV2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV} and 12.4±5.3±5.8MeV12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}, respectively. In addition, evidence of a new decay mode Ξc(2790)0Λc+K\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-} is found with a significance of 3.7σ3.7\,\sigma. The relative branching fraction of BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} with respect to the BD+DKB^{-} \to D^{+} D^{-} K^{-} decay is measured to be 2.36±0.11±0.22±0.252.36 \pm 0.11 \pm 0.22 \pm 0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

    Measurement of the ratios of branching fractions R(D)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

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    The ratios of branching fractions R(D)B(BˉDτνˉτ)/B(BˉDμνˉμ)\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu}) and R(D0)B(BD0τνˉτ)/B(BD0μνˉμ)\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu}) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb1{ }^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τμντνˉμ\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}. The measured values are R(D)=0.281±0.018±0.024\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024 and R(D0)=0.441±0.060±0.066\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ=0.43\rho=-0.43. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

    Feasibility of the Use of Variable Speed Drives in Center Pivot Systems Installed in Plots with Variable Topography

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    Pumping systems are the largest energy consumers in center pivot irrigation systems. One action to reduce energy consumption is to adjust the pumping pressure to that which is strictly needed by using variable speed drives (VSDs). The objective of this study was to determine the feasibility of including VSDs in pumping systems that feed center pivot systems operating in an area with variable topography. The VSPM (Variable Speed Pivot Model) was developed to perform hydraulic and energy analyses of center pivot systems using the EPANET hydraulics engine. This tool is able to determine the elevation of each tower for each position of the center pivot using any type of digital elevation model. It is also capable of simulating, in an accurate manner, the performance of the center pivot controlled with a VSD. The tool was applied to a real case study, located in Albacete, Spain. The results show a reduction in energy consumption of 12.2%, with specific energy consumptions of 0.214 and 0.244 kWh m&minus;3 of distributed water obtained for the variable speed and fixed speed of the pumping station, respectively. The results also show that for an irrigation season, to meet the water requirements of the maize crop in the region of the study (627 mm), an average annual savings of 14,107.35 kWh was obtained, which resulted in an economic savings of 2821.47&euro;

    Economic Viability and Quality of Grapes Produced with and without Plastic Covering

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    Viticulture began growing in Brazil in recent years, and this growth is due to the introduction of new techniques and improvements used in vine planting, especially the use of plastic covering in the vineyard. Thus, this study aimed to evaluate the economic viability of plastic covering installation, as well as the quality of grapes produced by two cultivars, in order to compare these results with those obtained by a conventional cultivation system. The experiment was performed at an experimental farm producing grapes in southern Brazil. The grape cultivars Niagara Branca and Niagara Rosada were studied and cultivated with and without plastic covering. Data related to the costs of vineyard planting, establishment, and seasonal management, in addition to the grape revenue, were assessed. Additionally, the grape yield and quality were evaluated. The analysis of return indicators showed that the net present value was higher for the plastic-covered system, which indicates greater profitability and consequent viability of the investment. Moreover, the grape quality varied according to the cultivar and production system. In this context, it is recommended to use the cultivar Niagara Rosada for production in a plastic covering system

    Machine Learning and Conventional Methods for Reference Evapotranspiration Estimation Using Limited-Climatic-Data Scenarios

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    Reference evapotranspiration (ET0) is one important agrometeorological parameter for hydrological studies and climate risk zoning. ET0 calculation by the FAO Penman–Monteith method requires several input data. However, the availability of climate data has been a problem in many places around the world, so the study of scenarios with different combinations of climate data has become essential. The aim of this study was to evaluate the performance of artificial neural network (ANN), random forest (RF), support vector machine (SVM), and multiple linear regression (MLR) approaches to estimate monthly mean ET0 with different input data combinations and scenarios. Three scenarios were evaluated: at the state level, where all climatological stations were used (Scenario I–SI), and at the regional level, where the Minas Gerais state was divided according to the climatic classifications of Thornthwaite (Scenario II–SII) and Köppen (Scenario III–SIII). ANN and RF performed better in ET0 estimation among the models evaluated in the SI, SII, and SIII scenarios with the following data combinations: (i) latitude, longitude, altitude, month, mean, maximum and minimum temperature, and relative humidity and (ii) latitude, longitude, altitude, month, mean temperature, and relative humidity. SVM and MLR models are recommended for all scenarios in situations with limited climatic data where only air temperature and relative humidity data are available. The results and information presented in this study are important for the agricultural chain and water resources in Minas Gerais state

    Measurement of the Λb0J/ψΛ\Lambda^0_b\rightarrow J/\psi\Lambda angular distribution and the Λb0\Lambda^0_b polarisation in pppp collisions

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    International audienceThis paper presents an analysis of the Λb0 {\Lambda}_b^0 → J/ψΛ angular distribution and the transverse production polarisation of Λb0 {\Lambda}_b^0 baryons in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The measurements are performed using data corresponding to an integrated luminosity of 4.9 fb1^{−1}, collected with the LHCb experiment. The polarisation is determined in a fiducial region of Λb0 {\Lambda}_b^0 transverse momentum and pseudorapidity of 1 < pT_{T}< 20 GeV/c and 2 < η < 5, respectively. The data are consistent with Λb0 {\Lambda}_b^0 baryons being produced unpolarised in this region. The parity-violating asymmetry parameter of the Λ → pπ^{−} decay is also determined from the data and its value is found to be consistent with a recent measurement by the BES III collaboration.[graphic not available: see fulltext

    Observation of New Ξc0\Xi_c^0 Baryons Decaying to Λc+K\Lambda_c^+ K^-

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    International audienceThe Λc+K- mass spectrum is studied with a data sample of pp collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 5.6  fb-1 collected by the LHCb experiment. Three Ξc0 states are observed with a large significance and their masses and natural widths are measured to be m[Ξc(2923)0]=2923.04±0.25±0.20±0.14  MeV, Γ[Ξc(2923)0]=7.1±0.8±1.8  MeV, m[Ξc(2939)0]=2938.55±0.21±0.17±0.14  MeV, Γ[Ξc(2939)0]=10.2±0.8±1.1  MeV, m[Ξc(2965)0]=2964.88±0.26±0.14±0.14  MeV, Γ[Ξc(2965)0]=14.1±0.9±1.3  MeV, where the uncertainties are statistical, systematic, and due to the limited knowledge of the Λc+ mass. The Ξc(2923)0 and Ξc(2939)0 baryons are new states. The Ξc(2965)0 state is in the vicinity of the known Ξc(2970)0 baryon; however, their masses and natural widths differ significantly

    Precision measurement of the Bc+B_{c}^{+} meson mass

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    International audienceA precision measurement of the Bc+ {B}_c^{+} meson mass is performed using proton- proton collision data collected with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to a total integrated luminosity of 9.0 fb1^{−1}. The Bc+ {B}_c^{+} mesons are reconstructed via the decays Bc+ {B}_c^{+} → J/ψπ+^{+}, Bc+ {B}_c^{+} → J/ψπ+^{+}π^{−}π+^{+}, Bc+J/ψppπ+ {B}_c^{+}\to J/\psi p\overline{p}{\pi}^{+} , Bc+J/ψDs+ {B}_c^{+}\to J/\psi {D}_s^{+} , Bc+ {B}_c^{+} → J/ψ D0^{0}K+^{+} and Bc+Bs0π+ {B}_c^{+}\to {B}_s^0{\pi}^{+} . Combining the results of the individual decay channels, the Bc+ {B}_c^{+} mass is measured to be 6274.47 ± 0.27 (stat) ± 0.17 (syst) MeV/c2^{2}. This is the most precise measurement of the Bc+ {B}_c^{+} mass to date. The difference between the Bc+ {B}_c^{+} and Bs0 {B}_s^0 meson masses is measured to be 907.75 ± 0.37 (stat) ± 0.27 (syst) MeV/c.[graphic not available: see fulltext
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