Infiltration characteristics of furrow irrigation in a heavy-textured soil

The objective of this thesis is to study the rate and pattern of infiltration of soil water, under the conditions of heavy texture and shallow depth in a tropical furrow- irrigated soil. The analysis is the result of a series of field-experiments and is supported by theories that has been proposed by others.The experiments were carried out in the Cojedes-Sarare Irrigation Project, Portuguesa State, Venezuela. Furrows with a length of 200 m, spaced at w = 0.70 m, and with an average slope of 0. 18 % were used. Three series of experiments were set out: (i) First series with variable inflow and surface roughness; (ii) Second series with variable initial soil moisture content; (iii) Third series with variable furrow length. Replicates of the treatments were distributed at random.Five irrigations were applied to the land during the period from January to March, 1970. Subsequently in the first series of experiments, first, third and fourth irrigations for three roughness conditions and four sizes of flow were tested. The second irrigation was used for the second series of experiments. The fifth irrigation served for the third series of experiments.During the first series of experiments, the following measurements were taken: (i) rate of advance of the water front (distance x in m at time t in min); (ii) furrow section parameters (top width T and depth h ); (iii) furrow inflow Q and outflow Q out . During the second and the third series of experiments, only the simultaneous inflow and outflow were recorded.Advance and infiltration functions were obtained for the period of advance of the water front (first stage), and infiltration functions for the period of wetting the root zone (second stage). Exponential equations were obtained by computer analysis for single furrow trials. Then, by averaging coefficients and exponents of the equations of the replicates, general equations for each treatment were found.The data of x as a function of t showed a good fit with the equation x = p t r . The coefficient p increased significantly with the flow size Q and the exponent r showed a trend to decrease although not significantly, with increasing Q . The coefficients of variation of p and r were rather high. Therefore a single furrow advance trial may not suffice to express the average field advance of the water front under the given conditions.The advance curves showed that the differences in roughness were great between the first irrigation with loose furrows and those irrigations after two or three applications have taken place. The roughness conditions appeared to be identical for third and fourth irrigations.With distance-averages of the furrow section parameters h and T , for three water front advance stages ( x = 87.5 m, x = 137,5 m and x = 175.0 m), the average section a f , and the average wetted perimeter P were obtained for a parabolic section of the furrows. The surface volume V f = a f p t r , and the area of infiltration A i (net area A in = P pt r and gross area A ig = w pt r ) were then arrived at.The infiltration functions were found for each treatment during the first stage, as V i= f(t) by using single furrow data of V i = Q t - V s ,. As the average infiltration depth I cum = V i / A i , the equations for I cum= f(t) were obtained. Equating these functions with the equation I cum = F at b+1/( b + 1) ( b + 2), the parameters a and b of the Kostiakov equation ( I = a t b ) were derived. For the second stage (when x = L = 175.0 m), the infiltration function was obtained by simultaneous measurements of the inflow and outflow, as infiltration flow: Q i = Q - Q out , from which the parameters of the infiltration equations, were found.The increase of infiltration with inflow size was clearly shown from the data analysis of both stages as being the effect of a larger volume of water. The parameters of the infiltration equation for the first stage altered in successive irrigations.Some emphasis was put on the unit inflow function q0 to relate flow sizes for both stages with length of run and infiltration. Equations for the unit inflow q0 = Q / A i and for unit infiltration flow q i = Q i / A i per unit area, were obtained for each treatment. Then a generalized type of equation was introduced which relates the unit inflow function with the average depth of water infiltrated during the advance time at the furrow intake. An equation to predict the length of advance is included x = φ( Q ) t 0.927, for the surface roughness and soil conditions under which the experiments were carried out. The representation of q0= f(t) and q i = f(t) for both stages, in a composite figure with the advance function as a function of time, provides an illustration of the infiltration process, usable for the design and management of furrow irrigation under the conditions of the experiments.The relationship between the exponent of time in the advance equation and the exponent of time in the infiltration equation was analysed with the data from the experiments. This analysis confirmed that r increases when ( b + 1) decreases. This agrees with findings in the literature, such as the relationship proposed by FOK and BISHOP (1965) Values for the surface storage coefficient C 1 = D / D0 , and infiltration coefficient C 2 = I cum / I cum0 to solve the balance equation for predicting advance were also obtained.The second series of experiments, in which infiltration rate was measured during the second stage, as a function of the initial moisture content, showed that the value of the coefficient a of the Kostiakov equation increased not significantly as the initial content of soil moisture decreases.The third series of experiments - measurements taken during the second stage - showed that upon the increase of furrow length, the coefficient a of the infiltration equation decreases and the exponent b increases.Water losses by deep percolation and by run-off at the end of the run, were finally analysed on the bases of the equations found and the data available. The analysis was made for the case of constant inflow for both stages (third irrigation), and for the case of reduced inflow during the second stage (fourth irrigation).The data analysis showed that infiltration is a very variable factor affected by the conditions of the soil and the surface of the channel bed, as well as by the size of the flow, furrow length and stage of irrigation. Soil cracking upon drying was found to be a relevant factor in the entry of water into the soil. Because deep percolation losses are certainly very small under the indicated physical conditions, irrigation efficiency will be rather high if provisions are made to use a cut-back stream, during the second stage, in order to lose a minimum of water by run-off at the end of the run

Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory

Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius $A$. Also the events detected simultaneously by the surface and fluorescence detectors (the `hybrid' data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction.Comment: Matches published versio

Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{$6\times 10^{19}$eV}. The anisotropy was measured by the fraction of arrival directions that are less than $3.1^\circ$ from the position of an active galactic nucleus within 75 Mpc (using the V\'eron-Cetty and V\'eron $12^{\rm th}$ catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is $(38^{+7}_{-6})$, compared with $21$ expected for isotropic cosmic rays. This is down from the early estimate of $(69^{+11}_{-13})$. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201

The Fluorescence Detector of the Pierre Auger Observatory

The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics Research Section

Advanced functionality for radio analysis in the Offline software framework of the Pierre Auger Observatory

The advent of the Auger Engineering Radio Array (AERA) necessitates the development of a powerful framework for the analysis of radio measurements of cosmic ray air showers. As AERA performs "radio-hybrid" measurements of air shower radio emission in coincidence with the surface particle detectors and fluorescence telescopes of the Pierre Auger Observatory, the radio analysis functionality had to be incorporated in the existing hybrid analysis solutions for fluoresence and surface detector data. This goal has been achieved in a natural way by extending the existing Auger Offline software framework with radio functionality. In this article, we lay out the design, highlights and features of the radio extension implemented in the Auger Offline framework. Its functionality has achieved a high degree of sophistication and offers advanced features such as vectorial reconstruction of the electric field, advanced signal processing algorithms, a transparent and efficient handling of FFTs, a very detailed simulation of detector effects, and the read-in of multiple data formats including data from various radio simulation codes. The source code of this radio functionality can be made available to interested parties on request.Comment: accepted for publication in NIM A, 13 pages, minor corrections to author list and references in v

Search for First Harmonic Modulation in the Right Ascension Distribution of Cosmic Rays Detected at the Pierre Auger Observatory

We present the results of searches for dipolar-type anisotropies in different energy ranges above $2.5\times 10^{17}$ eV with the surface detector array of the Pierre Auger Observatory, reporting on both the phase and the amplitude measurements of the first harmonic modulation in the right-ascension distribution. Upper limits on the amplitudes are obtained, which provide the most stringent bounds at present, being below 2% at 99% $C.L.$ for EeV energies. We also compare our results to those of previous experiments as well as with some theoretical expectations.Comment: 28 pages, 11 figure

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter