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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Experiments with subsurface irrigation and drainage on a sandy soil in Quebec

Memon, Nisar Ahmed. January 1985 (has links)
Field experiments were conducted on St-Samuel sandy loam soil in 1982 and 1983, with eight replicates of irrigated and non-irrigated maize plots. Soil moisture regime, root density and maize yields were determined to demonstrate the effect of subsurface irrigation and drainage systems. / Laboratory experiments were conducted on large and small undisturbed soil cores to determine pertinent soil properties, relating drainable volume and steady upward flux to water table depth. / A water balance model was developed and used with a stress-day-index to predict water table depth, excessive and deficit soil moisture conditions and effects on corn yield. Economic analyses were made to identify subsurface irrigation/drainage designs which optimize the profit for a corn crop. / A simple method based on first and second order moments was proposed to determine the effects of parameter uncertainty in the relationship of steady upward flux vs water table depth on subsurface irrigation/drainage design parameters. / Based on the above information, a realistic subsurface irrigation/drainage design was proposed and operational recommendations were made for an example field.
82

Head losses and water distribution in a sandy loam soil with a subirrigation system

Bournival, Pierre January 1988 (has links)
No description available.
83

Effect of different sulphur fertilisation rates on plant productivity and on changes in sulphur content in soil and plants / Skirtingo tręšimo siera poveikis augalų produktyvumui ir jos kaitai dirvožemyje bei augaluose

Staugaitienė, Rūta 10 September 2014 (has links)
Objective of the research – the research was to determine the effect of different sulphur fertilisation rates on the mineral sulphur content in soil and the seed/grain yield and quality of spring rape and spring wheat crops grown on low in sulphur sandy light loam Epicalcari – Endohypogleyic Cambisols and very low in sulphur sandy loam on light loam Orthi-Haplic Luvisols. Tasks of the research: To determine the effect of different sulphur fertilisation rates applied to low in sulphur sandy light loam Epicalcari – Endohypogleyic Cambisols and very low in sulphur sandy loam on light loam Orthi-Haplic Luvisols on: • Spring rapeseed yield and crop structural elements; • Spring rapeseed quality; • Spring wheat yield and crop structural elements; • Spring wheat grain quality; • Changes in the mineral sulphur content in soil. / Tyrimų tikslas – nustatyti skirtingų sieros trąšų normų įtaką vasarinių rapsų ir vasarinių kviečių derliui, jo kokybei bei mineralinės sieros kiekiui mažai ir labai mažai sieringame smėlingame lengvo priemolio sekliai karbonatingajame giliau glėjiškajame rudžemyje (Epicalcari – Endohypogleyic Cambisol ) ir priesmėlio ant lengvo priemolio tipingajame paprastajame išplautžemyje (Orthi-Haplic Luvisol). Tyrimų uždaviniai: Nustatyti sieros trąšų normų įtaką mažai ir labai mažai sieringame smėlingame lengvo priemolio sekliai karbonatingajame giliau glėjiškajame rudžemyje (Epicalcari – Endohypogleyic Cambisol ) ir priesmėlio ant lengvo priemolio tipingajame paprastajame išplautžemyje (Orthi-Haplic Luvisol): • Vasarinių rapsų sėklų derliui ir struktūros elementams. • Vasarinių rapsų sėklų kokybei. • Vasarinių kviečių derliui ir struktūros elementams • Vasarinių kviečių grūdų kokybei. • Mineralinės sieros kiekio pokyčiams dirvožemyje.
84

Ethics in Photojournalism: Authenticity and Sensitivity in Coverage of Tragic Events

Shields, Minla Linn 10 May 2014 (has links)
Photojournalism captures moments within an event or space in time that are used to tell a larger story. Photographs are powerful tools for communication because these moments not only represent facts; they also have an ability to speak to viewers on a relatable and emotional level. With this power comes ethical responsibility and natural tension points between photograph, and journalistic practices. Journalism’s ethics codes group points of discussion specific to photographs into categories of manipulation, privacy, or graphic content. This thesis argues that these issues fall into broader overlapping themes of authenticity and sensitivity. Using visual analysis of four photographs from the Boston Marathon bombing and Newtown school shooting, it considers how journalists deal with the relationship between photography and journalistic theory using this ethical framework of authenticity and sensitivity. It concludes with a discussion of best practices for coverage of tragic events from the real-world perspective of the photojournalist.
85

Teleconnective Influences on the Strength of Post-tropical Cyclones

Young, Jeremy 01 December 2012 (has links)
Over the 1951-2009 time period, 47% of all tropical systems in the Atlantic Basin transitioned to post-tropical storms. These storms are capable of producing hurricaneforce winds, torrential, flooding rains and storm surge that floods coastal areas. This study adds to previous climatological work by completing a case-study of Hurricane Ike (2008) and examining how teleconnections such as the El Niño Southern Oscillation (ENSO), the Madden-Julian Oscillation (MJO), the Atlantic Multidecadal Oscillation (AMO) and the Pacific Decadal Oscillation (PDO) contribute to the strength of a transitioning post-tropical storm. T-tests performed show strong statistical relationships between an increase (decrease) in post-tropical storm frequency and warm PDO – La Niña (cold PDO – La Niña), cold PDO – ENSO neutral (warm PDO – ENSO neutral), and warm (cold) AMO conditions. Moreover, nearly significant results were found for the same increase (decrease) and La Niña seasons since (pre) 1980 and for cold (warm) PDO conditions. Modeling the MJO suggests that increased (decreased) relative humidity associated with the wet (dry) phase could increase (decrease) precipitation output from the storm and decrease (increase) forward speed of the storm, decreasing (increasing) wind speeds observed at the surface.
86

Modelling the influence of fines on liquefaction behaviour

Rahman, Md. Mizanur, Engineering & Information Technology, Australian Defence Force Academy, UNSW January 2009 (has links)
Traditionally, void ratio, e has been used as a state variable for predicting the liquefaction behaviour of soils under the Critical State (Steady State) framework. Recent publications show that void ratio, e may not be a good parameter for characterizing sand with fines as the steady state, SS data points move downward in e-log(p) space up to certain fines content termed as threshold fines content, TFC. Thus, it was difficult to apply SS concept on sand with fines as a small variation of fines content may lead to different SS line. Many researchers proposed to used equivalent granular void ratio, e* as an alternative state variable (i.e. in lieu of void ratio, e) in attempt to obtain a narrow trend line for SS data points irrespective of fc provided fc  TFC. The e* is obtained from e. For the conversion from e to e*, one need a parameter b which presents the active fraction of fines in overall force structure of sand. However, predicting the b is problematic. Most, if not all, of the b reported were determined by case-specific back-analysis, that is, the b-value was selected so that the test results for a given sand-fines type could be correlated with the equivalent granular void ratio, e* irrespective of fines content. This thesis examines the factors that affecting the b value by examining published work on binary packing. This leads to a simple semi-empirical equation for predicting the value of b based onparticle size ratio,  and fines content, fc. Published data and experimental results on Sydney sand appears to be in support of the proposed equation. The single relation of SS data points in e*-log(p) space for sand with fines is referred as Equivalent Granular Steady State Line, EG-SSL. The EG-SSL is then used to define the equivalent granular state parameter,*. A good correlation observed between * and q-p, q- q responses in undrained shearing. The e* and * are also used to modified a state dependent constitutive model. Seven model input parameters are needed in addition four to critical state input parameters. These parameters are obtained from drained test. The model is used to predict q-pand q- q responses for flow, non-flow and limited flow behaviour for 0% to 30% fines contents. The model predictions are in good agreement with experimental results. The effect of fines types (in terms of plasticity and angularity) on the prediction equation of b are also examined with four different types of fines. A negligible effect of fines type on the prediction equation of b is observed. The link between monotonic and cyclic loading behaviour for sand with fines are also examined with emphasis on cyclic instability and strain hardening behaviour after quasi steady state, QSS for a range of fines contents (provided that fc < TFC). It is found that a single set of rules could be used to correlate monotonic and cyclic behaviour for a range of fines contents at same *.
87

Teacher training workshop in the small Associate Reformed Presbyterian Church

Cavin, Meredith Lee. January 1994 (has links)
Thesis (D. Min.)--Erskine Theological Seminary, 1994. / Includes bibliographical references (leaves lxi-lxx).
88

Disposal of a primary papermill sludge on sandy cropland soil

Huettl, Peter Joseph Vincent, January 1982 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
89

The effects of dams in the Big Sandy watershed using a novel bacteria-based bioindicator of water quality /

Loughman, Kathleen Riha. January 2005 (has links)
Theses (M.S.)--Marshall University, 2005. / Title from document title page. Includes abstract. Document formatted into pages: contains viii, 105 p. including illustrations and maps. Bibliography: p. 37-40.
90

Estudo dos mecanismos de fluidização de areias com jatos de água / Study of the fluidisation mechanism in sandy soils using water jets

Mezzomo, Samuel Maggioni January 2009 (has links)
A fluidização é definida como a suspensão de partículas de um solo granular devido à ação de um fluxo ascendente, que cria uma força de arrasto suficiente para suportar o peso próprio das partículas, produzindo uma zona fluidizada. Neste trabalho são discutidos os mecanismos e os conceitos envolvidos na fluidização de solos arenosos com a utilização de jatos de água, que futuramente podem ser associados a novas tecnologias de instalação de ancoragens de plataformas de petróleo offshore. O estudo foi baseado em ensaios realizados em câmaras de calibração retangulares, com paredes em acrílico, preenchidas com areias de granulometria distintas, compactadas com densidade relativa de 50% e 100%. O sistema de jateamento consiste basicamente em uma bomba centrífuga que succiona a água armazenada em um reservatório e a conduz, através de um circuito hidráulico, à extremidade de tubos metálicos verticais, responsáveis pelo jateamento de água. Foram utilizados tubos com diferentes diâmetros e diversas velocidades de saída do jato. Iniciado o jateamento, tem-se a formação de um leito fluidizado, com formato côncavo e interface bem definida com a zona não fluidizada. O jato de água penetra certa profundidade no interior do leito fluidizado até ser defletido, no sentido ascendente, carregando partículas de areia que são depositadas ao redor da zona fluidizada. Após a formação de uma geometria fluidizada máxima, os tubos são reposicionados em uma nova profundidade. A fluidização ao longo da profundidade apresenta comportamento definido, com uma geometria inicialmente estável, que alcança uma condição de instabilidade em determinada profundidade, até sofrer sucessivos fechamentos, formando uma cavidade submersa fluidizada. Esta cavidade diminui de tamanho com o aumento da profundidade e a fluidização do solo deixa de ocorrer para certa profundidade de saída do jato. Os parâmetros principais que comandam a geometria da zona fluidizada aberta são a velocidade de saída e o diâmetro do jato, em conjunto com o tamanho das partículas do solo. Não foi observada influência da densidade relativa de compactação da areia na geometria fluidizada final. As dimensões geométricas são função do número densimétrico de Froude, cujo emprego permite a determinação de equações empíricas que descrevem o comportamento da geometria fluidizada aberta. O conjunto de ensaios de laboratório possibilitou determinar os parâmetros de controle dos mecanismos de fluidização em areias e a influência destes parâmetros no comportamento do solo fluidizado. / Fluidisation occurs when a granular soil is subjected to an upward fluid flow which creates a drag force sufficient to support the weight of the particles, producing a fluidised zone. In the present work a discussion is made on the mechanisms and concepts controlling the fluidised process produced by upflow washing in granular materials, aiming at the installation of offshore platform anchors. The study was carried out in laboratory rectangular calibration chambers filled with sand at relative densities ranging from 50% to 100%. The upflow washing was produced by a centrifuge pump that sucks water from a reservoir and conducts the water through a hydraulic system to the extremity of a vertical metalic tube, producing the water jet flow. Tubes with different diameters and fluid velocities have been used. The mechanism initiates with the formation of an open fluidised zone having a characteristic shape and distinct boundaries. The fluid penetrates up to a given depth and is deflected towards the surface. Once a stabilized zone is produced, the jet is lowered to another depth and the process is repeated. The shape of the fluidised zone changes with increasing jet depth from an open and stable approximately ellipsoidal form to an unstable spouted profile, and then to a submerged fluidised cavity. The shape of the cavity reduces with increasing depth. Parameters controlling the geometry of an open fluidised zone are fluid velocity and inside diameter of jet, together with diameter soil particles. There has been no influence of relative density in the geometry of the fluidised zone. In fact, this geometry is expressed by densimetric Froude number. The present work was usefull in demonstrating the parameters controlling fluidisation by upflow washing.

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