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Sample records for density irrigation frequency

  1. Effect of planting density and cutting frequency on forage and grain yields of kochia (Kochia scoparia under saline water irrigation

    Directory of Open Access Journals (Sweden)

    mseou ziyaeii

    2009-06-01

    Full Text Available AField experiment was conducted at Research Farms of Center of Excellence for Special Crops, Ferdowsi University of Mashhad, Mashhad, Iran, in 2006 to evaluate the effect of planting density on forage and grain yield of kochia (Kochia scoparia. Experimental design was a randomized complete block with split-plot arrangement of treatments,with three replications, where different planting densities (10, 20, 30 and 40 plant m-2 were assigned to main plots and number of cutting (including a single cutting, two cutting and no cutting i.e. allowing the crop to grow until maturity allocated to sub-plots. At each harvest date (cutting the biological yield, leaf and stem dry weight, plant height, number of branches and the individual plant biomass were measured. Grain yield and thousand seed weight were also determined at the end of growing season. Result showed the highest biological yield and leaf and stem dry weights for kochia obtaind at 30 plant m-2. The total biomass, leaf and stem dry weights, plant height, number of branches were greater for the first cutting as compared to the second cutting. Planting density and cutting number interacted to affect the leaf dry weight. At physiological maturity stage there were no significant differences among planting densities for plant height and number of branches. The best planting density, in terms of biomass production and leaf and stem dry weight, was found as 30 plant m-2, while for grain production a planting density of 20 plant m-2 could be recommended. Key words: Kochia, planting density, sward, biological yield, grain production.

  2. to Irrigation Intervals and Plant Density in Zuru, Northern Guinea

    African Journals Online (AJOL)

    ISSN 0794-5698. Response of Onion (Allium cepa L.) to Irrigation Intervals and Plant Density in ... The treatments were laid out in a split plot design with three replications. Irrigation ..... System and Agronomic Practice in. Tropical Climates.

  3. Irrigation and fertigation frequencies with nitrogen in the watermelon culture

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    Carlos Newdmar Vieira Fernandes

    2014-06-01

    Full Text Available This study evaluates the influence of different irrigation frequencies and different nitrogen fertigation frequencies on the growth performance of the watermelon (Citrullus lanatus culture. Two experiments were conducted at the Paraguay farm in the Cruz municipality, Ceará, Brazil. They was randomized blocks design with six treatments and four replications. The irrigation frequency experiment consisted of the application of different irrigation frequencies. The treatments were: DM - daily irrigation in the morning with 100% daily dosage; DT - daily irrigation in the afternoon, with 100% daily dosage; DMT - twice daily irrigation, with 50% daily dosage in the morning and 50% daily dosage in the afternoon; 2D - irrigation every two days; 3D - irrigation every three days and 4D - irrigation every four days. To the experiment with different nitrogen fertigation frequencies, the treatments used were: 2F - 2 fertigations in a cycle; 4F - 4 fertigations in a cycle; 8F - 8 fertigations in a cycle; 16F - 16 fertigations in a cycle; 32F - 32 fertigations in a cycle and 64F - 64 fertigations in a cycle. We evaluated the marketable yield (PC, fruit weight (M, polar diameter (DP, equatorial diameter (DE, shell thickness (EC and soluble solids (SS. The irrigation frequency treatments influenced all variables significantly, with twice daily irrigation (DMT, 50% in the morning and the 50% in the afternoon promoting the highest productivity (69.79 t ha-1. The different frequencies of fertigation also significantly influenced all variables, except for the shell thickness, the highest yield (80.69 t ha-1 being obtained with treatment 64 fertigations in a cycle.

  4. Effect of irrigation frequencies on grain yield of maize

    International Nuclear Information System (INIS)

    Ahmad, M.; Chaudhry, M.H.; Amjed, M.T.

    2008-01-01

    To find out the water requirement and its application frequencies in spring Maize a trial was designed. The trial was comprised of five maize varieties (Ev-5098, EV-6098, EV-1098, Composite-20 and Pack Afgoyee) and five irrigation frequencies (7,8,9,10 and 11). The trial was sown in split plot design with three replication, keeping varieties in main plots and irrigation frequencies in sub plots. The plot size was 5m x 4.5 with 75cm apart rows and plant to plant distance was 15 com to maintain the 88888 plants per hectare. The trial was conducted during spring 2000 and 2001. Data were collected for days to 50% silking. Plant height (cm), cob height (cm) and grain yield per hectare. The data were analyzed and results obtained which revealed highly significant differences among varieties and also among irrigation frequencies in all the characters studied during both the years and in pooled analysis over years. The interaction between varieties and irrigation frequencies was highly significant for grain yield kg ha/sup -1/ and significant for other characters studied in year wise as well as in pooled analysis. Years effect was also high significant which is clear from the table of weather data which shows that temperature remained high during the crop season of 2001 as compared to 2000 along with high temperature more rains were also received in March. April and May in 2001 while in 2000 rain was received only in February. Three was gradual decrease in days to 50% silking with the increase in number of irrigations in all the varieties while plant height, cob height and grain yield increased with every addition of irrigation. Trend of increase or decrease remained the same during both the year. All the varieties separately or in combine showed better results during spring 2001, maximum grain yield was obtained by EV-5098 (full duration variety) with 11 irrigations during both the years 2000 and 2001 i.e. 3511 and 6140 kg ha/sup -1/ while EV-1098 (short duration variety

  5. Growth and Flowering Responses of Cut Chrysanthemum Grown under Restricted Root Volume to Irrigation Frequency

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    Viyachai Taweesak

    2014-01-01

    Full Text Available Influences of irrigation frequency on the growth and flowering of chrysanthemum grown under restricted root volume were tested. Chrysanthemum cuttings (Chrysanthemum morifolium “Reagan White” were grown in seedling tray which contained coconut peat in volumes of 73 and 140 cm3. Plants were irrigated with drip irrigation at irrigation frequencies of 4 (266 mL, 6 (400 mL, and 8 (533 mL times/day to observe their growth and flowering performances. There was interaction between irrigation frequency and substrate volume on plant height of chrysanthemum. Plants grown in 140 cm3 substrates and irrigated 6 times/day produced the tallest plant of 109.25 cm. Plants irrigated 6 and 8 times/day had significantly higher level of phosphorus content in their leaves than those plants irrigated 4 times/day. The total leaf area, number of internodes, leaf length, and leaf width of chrysanthemums grown in 140 cm3 substrate were significantly higher than those grown in 73 cm3 substrate. The numbers of flowers were affected by both irrigation frequencies and substrate volumes. Chrysanthemums irrigated 8 times/day had an average of 19.56 flowers while those irrigated 4 times/day had an average of 16.63 flowers. Increasing irrigation frequency can improve the growth and flowering of chrysanthemums in small substrate volumes.

  6. Agronomic and physiological impacts of irrigation frequency on green basil (Ocimum basilicum L.)

    OpenAIRE

    Gao, Peng; Dodd, Ian

    2015-01-01

    Water scarcity is a major factor restricting agricultural production and irrigation globally, with sustainable agricultural development calling for less irrigation water use and more production per unit of water applied. Improved understanding of plant physiological responses to water stress, and the effect of irrigation frequency on plant biomass production and quality, may help to optimize irrigation scheduling. Glasshouse-grown basil (Ocimum basilicum L.) received three different irrigatio...

  7. Drip irrigation in coffee crop under different planting densities: Growth and yield in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Gleice A. de Assis

    2014-11-01

    Full Text Available Irrigation associated to reduction on planting spaces between rows and between coffee plants has been a featured practice in coffee cultivation. The objective of the present study was to assess, over a period of five consecutive years, influence of different irrigation management regimes and planting densities on growth and bean yield of Coffea arabica L.. The treatments consisted of four irrigation regimes: climatologic water balance, irrigation when the soil water tension reached values close to 20 and 60 kPa; and a control that was not irrigated. The treatments were distributed randomly in five planting densities: 2,500, 3,333, 5,000, 10,000 and 20,000 plants ha-1. A split-plot in randomized block design was used with four replications. Irrigation promoted better growth of coffee plants and increased yield that varied in function of the plant density per area. For densities from 10,000 to 20,000 plants ha-1, regardless of the used irrigation management, mean yield increases were over 49.6% compared to the non-irrigated crop.

  8. Effect of irrigation frequency and application levels of sulphur ...

    African Journals Online (AJOL)

    Administrator

    2011-09-21

    Sep 21, 2011 ... both years of experimentation, application of two irrigations significantly increased the India ... marginal lands with poor fertility under rainfed conditions. ... and 40 kg K20 ha-1 as muriate of potash was applied to each plot.

  9. Effect of irrigation frequency and application levels of sulphur ...

    African Journals Online (AJOL)

    A field experiment was conducted at Indian Agricultural Research Institute, New Delhi during the crop season of 2007 to 2008 and 2008 to 2009 to study the effect of irrigation and sulphur on yield and water use efficiency of Indian mustard (Brassica juncea var. PusaJagannath). The experiment was carried out in split plot ...

  10. The effect of applying different water levels and irrigation frequencies in propagating rosemary (Rosmarinus officinalis L.

    Directory of Open Access Journals (Sweden)

    Javier Giovanni Álvarez Herrera

    2010-01-01

    Full Text Available Rosemary seedlings are obtained by vegetative propagation because the seeds present low viability. Despite being an expanding crop, there is little information on water consumption during the propagation stage. Water levels and irrigation frequencies were therefore applied using a completely randomised design having a 4 x 2 factorial arrangement. The first factor concerned irrigation frequency (4 and 8 days and the second concerned water level (0.6, 0.8, 1.0 and 1.2 evaporation inside the greenhouse. A 1.0 coefficient combined with 4-day irrigation frequency presented the best results regarding height (39.3 cm, fresh weight, dry weight and branch length (146 cm. Water level affected the fresh and dry weight of leaves regardless of frequency. Relative water content in leaves did not present differences due to environmental conditions minimising treatment effect. Rooting percent- tage showed no significant differences regarding irrigation frequency or water level. Irrigation frequency did not affect rosemary growing pattern because sphagnum retains high moisture content. The best branch number (34 was obtained with 1.0 coefficient and 4-day frequency, this being important from the production point of view because this is the material which is sold. Water management changes photoassimilate distribution in rosemary plants.

  11. Evaluation of Yield and Yield Components of Black Cumin (Nigella sativa L. under different Plant Density and Limited Irrigation Condition

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    Sh Rezvan Beidokhti

    2012-10-01

    Full Text Available Research on crop response to deficit irrigation is important to reduce agriculture water use in areas where water is limited resource. Using drought resistant landraces with irrigation scheduling based on phenological stages in semi-arid and arid regions may provide an opportunity to optimize irrigation efficiency and water savings in these regions. In order to evaluate of yield and yield components of black cumin under different plant density and limited irrigation condition an experiment was conducted in Research Farm of Islamic Azad University of Damghan during growing season of 2007-2008. The experimental treatments were arranged in split plots based on a complete randomized block design with three replications. The limited irrigation (based on phenological stages treatments were included: cutting irrigation at blooming (folded flowers, cutting irrigation at flowering stage, cutting irrigation at seed formation and normal weekly irrigation (control were allocated to the main plots and different plant density: 100, 150, 200 and 250 plant per square meter (m2 were allocated to sub plots. The results showed that the effect of limited irrigation, plant density and their interaction on plant height, number of follicle, follicle weight, number of seed, 1000 seed weight, seed yield, biological yield and harvest index Black Cumin. The highest yield and yield components was obtained in normal irrigation (control and 200 plant density and the lowest yield were obtained when irrigation cut at the blooming stage and 250 plant density. There was a significant correlation between seed yield and number (r=0.90, 1000 seed weight (r=0.95 and biological yield (r=0.97. Optimum plant density of black cumin was decreased under limited irrigation treatments. Under normal (control and limited irrigation, optimum plant density was 200 and 150 plant per (m2 respectively.

  12. White mold intensity on common bean in response to plant density, irrigation frequency, grass mulching, Trichoderma spp., and fungicide Intensidade do mofobranco em feijão em função de densidade de plantas, freqüência de irrigação, cobertura vegetal do solo, Trichoderma spp. e fungicida

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    Trazilbo José de Paula Júnior

    2009-02-01

    Full Text Available The purpose of this study was to evaluate the efficiency of integrated managements on white mold control on common bean. Initially, in vitro testing was made to assess the antagonism of 11 Trichoderma isolates against Sclerotinia sclerotiorum and to investigate fungicides (fluazinam and procymidone inhibitory effects on those fungi. In two field experiments the following combinations were tested: irrigation frequencies (seven or 14 days, plant densities (six or 12 plants per meter, and three disease controls (untreated control, fungicide or Trichoderma spp.. In a third experiment plant densities were replaced by grass mulching treatments (with or without mulching. Fluazinam was applied at 45 and 55 days after emergence (DAE. The antagonists T. harzianum (experiments 1 and 3 and T. stromatica (experiment 2 were applied through sprinkler irrigation at 10 and 25 DAE, respectively. Most of the Trichoderma spp. were effective against the pathogen in vitro. Fluazinam was more toxic than procymidone to both the pathogen and the antagonist. Fungicide applications increased yield between 32 % and 41 %. In field one application of Trichoderma spp. did not reduce disease intensity and did not increase yield. The reduction from 12 to six plants per meter did not decrease yield, and disease severity diminished in one of the two experiments. It is concluded that of the strategies for white mold control just reduction of plant density and applications of fungicide were efficient.Objetivou-se estudar a eficácia de técnicas de manejo integrado no controle do mofo-branco em feijão. Inicialmente, foram feitos testes in vitro para avaliar o antagonismo de 11 isolados de Trichoderma contra Sclerotinia sclerotiorum e investigar os efeitos de fungicidas (fluazinam e procymidone sobre esses fungos. Em dois ensaios de campo, foram testadas estas combinações: freqüências de irrigação (sete ou 14 dias, densidades de plantas (seis ou 12 por metro e três controles

  13. Yield of cherry tomatoes as a function of water salinity and irrigation frequency

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    Alexandre N. Santos

    2016-02-01

    Full Text Available ABSTRACT The use of brackish water in agriculture can cause salinization of soils and reduce plant yield. This problem can be minimized by hydroponic cultivation, which improves plant development. The aim of this study was to evaluate the yield of cherry tomatoes grown in hydroponic system with substrate under salinity levels of the nutrient solution (NS, exposure time to salinity and irrigation frequency. The experiment was conducted in a greenhouse, in a randomized complete block design, in a 6 x 2 x 2 factorial scheme with five replicates: six salinity levels of NS prepared with brackish water (3.01; 4.51; 5.94; 7.34; 8.71 and 10.40 dS m-1; two exposure times to NS (60 and 105 days and two irrigation frequencies (one irrigation per day and irrigation every two days. Yield and production components of cherry tomatoes cv. 'Rita' were evaluated. NS salinity affected plant yield, reducing fruit production, which was more significant when plants were subjected to a longer time of exposure to salinity. There was no difference between NS applications on fruit production, when these applications were performed once a day or once every two days.

  14. Plasticity in stomatal size and density of potato leaves under different irrigation and phosphorus regimes

    DEFF Research Database (Denmark)

    Sun, Yanqi; Yan, Fei; Cui, Xiaoyong

    2014-01-01

    The morphological features of stomata including their size and density could be modulated by environmental cues; however, the underlying mechanisms remain largely elusive. Here, the effect of different irrigation and phosphorus (P) regimes on stomatal size (SS) and stomatal density (SD) of potato...... potentially enhance water-use efficiency as exemplified by the lowered leaf δ13C under fluctuating soil moisture conditions....... leaves was investigated. The plants were grown in split-root pots under two P fertilization rates (viz., 0 and 100mgkg-1 soil, denoted as P0 and P1, respectively) and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation regimes. Results showed that SS and SD were...... unresponsive to P but significantly affected by the irrigation treatment. FI plants had the largest SS, followed by DI, and PRD the smallest; and the reverse was the case for SD. Compared to FI and DI, PRD plants had significantly lower values of specific leaf area (SLA) and leaf carbon isotope discrimination...

  15. Responses of Grain Maize to Plant Density at Different Irrigation Regimes

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    Sara SAMADVAND

    2017-12-01

    Full Text Available In order to examine the effects of different plant densities, plant patterns and irrigation regimes on yield, yield components and harvest index of grain maize, a field experiment was conducted at Miyandoab Agricultural Research Station, Iran. A strip split plot experiment was conducted based on randomized complete block design with three replications. The results showed that the effect of plant density was significant on kernel yield, harvest index, 1,000 kernel weight. The highest kernel yield was obtained from 90,000 plants ha-1 density. Maximum grain yield (18.530 t ha-1 was obtained from furrow irrigation. However, there was no significant difference between moisture levels of 100% and 120% of field capacity. The lowest kernel yield was obtained at 80% field capacity. This study also showed that mean kernel weight and the number of kernels per row were the most determinant factors in grain yield formation. The highest and the lowest harvest indices were obtained at 120% and 80% treatments of field capacity treatment, respectively.

  16. Effects of dripper discharge and irrigation frequency on growth and yield of maize in loess plateau of northwest china

    International Nuclear Information System (INIS)

    Xiukang, W.; Zhanbin, L.; Yingying, X.

    2014-01-01

    A field experiment was conducted at the Changwu Experimental Station in Changwu County, Shaanxi Province, in northwestern China from 2010 to 2011 with four treatments and six replicates in a randomized complete block design to determine appropriate dripper discharge and irrigation frequency for maize (Zea mays, L.) irrigated by drip irrigated system. Dripper discharge was applied to maize 1L/h of dripper discharge, 2 days irrigation frequency and 100% of evaporation from a class a pan (T1), 2, 3 and 4 L/h corresponding to 4, 6 and 8 days irrigation frequency, and deficit irrigation water levels was 90%, 80% and 70% of evaporation (T2, T3 and T4), respectively. The results indicated that longest root, root activity, plant height, leaf area, biomass and grain yields values were highest in T1 in both years. The highest grain yield was obtained of 8.78 and 8.84 t ha-1 under T1 in both years, and the minimum yield was obtained with 8.15 and 7.78 t ha-1 under T4 in 2010 and 2011, respectively. The maximum irrigation water use efficiency (IWUE) was 3.247 and 3.283 kg m-3 in both years under T4. Despite the reduction of growth and grain yield in T3, the dripper discharge was 3L/h, 6 days irrigation frequency and 80% of evaporation was still high and acceptable for maize production and irrigation water use efficiency in Loess Plateau of Northwest China. (author)

  17. EFFECTS OF IRRIGATION FREQUENCY AND LEAF DETACHMENT ON CHRYSANTHEMUM GROWN IN TWO TYPES OF PLASTIC HOUSE

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    K. Budiarto

    2016-10-01

    Full Text Available Chrysanthemum is one of important ornamentals in Indonesia and it ranks in the first quantity of cut flower marketed every year. In most cases, the low productivity is still a constraint for the traditional growers to make production process profitable. Several problems revealed in chrysanthemum production were investigated. The study dealt with the effect of two types of plastic house constructions, irrigation frequency, and leaf detachment on the growth and development of chrysanthemum. The experiment was conducted at Segunung, Indonesian Ornamental Plants Research Institute during the dry season of 2005. A nested design with six replications was used. The results showed that plants grown in wood-constructed plastic house had better growth performance and flower quality than those under bamboo plastic house. Longer stem and higher plant fresh weight with more flowers and longer life span were also observed on chrysanthemum irrigated four times per week than those irrigated twice per week. Leaf removal often practiced by the growers is no longer recommended, since the number of leaves on the plant influenced all parameters observed. The more leaves were detached, the more negative impacts on plant growth were found.

  18. Phenology of German Chamomile and its Changes under Different Irrigation Regimes and Plant Densities

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    Alireza PIRZAD

    2010-03-01

    Full Text Available In order to definite growth stages of Matricaria chamomilla L., 40 plants were planted with 200 200 cm distance from each other. To determine the phenology under different water stress condition and plant densities, an experiment was conducted in factorial based on randomized complete block design with two factors including irrigation at 4 levels (25, 50, 75, and 100 mm evaporation from pan class A, and plant density at 5 levels (cultivation in 30 cm rows with 5, 10, 15, 20 and 25 cm intra-row spaces with three replications. Definition of growth stages including the maximum number of nodes, sub stems and tillers were 21, 20 and 14 that were occurred at 970, 1088 and 1088 oC growth degree-days, respectively. The numbers of nodes were 28.6, 30.0, 30.2 and 27.8, of sub stem were 19.2, 18.4, 19.8 and 18.4; and of tillers were 14.8, 14.0, 15.0 and 14.4 that were obtained from irrigation at 25, 50, 75, and 100 mm evaporation from pan, respectively. In the other hand, the number of nodes as follow 28.25, 29.00, 29.75, 29.75 and 29.00; sub stem as 17.50, 20.00, 20.75, 19.00 and 17.50; and tillers were 15.00, 13.50, 14.75, 14.00 and 15.50 that were obtained from 5, 10, 15, 20 and 25 cm intra-row spacing, respectively. Differences by irrigation on GDDs values were observed at the second harvest. However the earliest observation of flower and seed receiving at the first harvest occurred on 5 cm intra-row spacing. These changes were identical by GDDs for second harvest of flower, but with mild slope of reduction. There were no differences in number of leaves and tillers among irrigation levels and plant densities.

  19. Phenology of German Chamomile and its Changes under Different Irrigation Regimes and Plant Densities

    Directory of Open Access Journals (Sweden)

    Alireza PIRZAD

    2010-03-01

    Full Text Available In order to definite growth stages of Matricaria chamomilla L., 40 plants were planted with 200 � 200 cm distance from each other. To determine the phenology under different water stress condition and plant densities, an experiment was conducted in factorial based on randomized complete block design with two factors including irrigation at 4 levels (25, 50, 75, and 100 mm evaporation from pan class A, and plant density at 5 levels (cultivation in 30 cm rows with 5, 10, 15, 20 and 25 cm intra-row spaces with three replications. Definition of growth stages including the maximum number of nodes, sub stems and tillers were 21, 20 and 14 that were occurred at 970, 1088 and 1088 oC growth degree-days, respectively. The numbers of nodes were 28.6, 30.0, 30.2 and 27.8, of sub stem were 19.2, 18.4, 19.8 and 18.4; and of tillers were 14.8, 14.0, 15.0 and 14.4 that were obtained from irrigation at 25, 50, 75, and 100 mm evaporation from pan, respectively. In the other hand, the number of nodes as follow 28.25, 29.00, 29.75, 29.75 and 29.00; sub stem as 17.50, 20.00, 20.75, 19.00 and 17.50; and tillers were 15.00, 13.50, 14.75, 14.00 and 15.50 that were obtained from 5, 10, 15, 20 and 25 cm intra-row spacing, respectively. Differences by irrigation on GDDs values were observed at the second harvest. However the earliest observation of flower and seed receiving at the first harvest occurred on 5 cm intra-row spacing. These changes were identical by GDDs for second harvest of flower, but with mild slope of reduction. There were no differences in number of leaves and tillers among irrigation levels and plant densities.

  20. Effects of different irrigation intervals and plant density on morphological characteristics, grain and oil yields of sesame (Sesamum indicum

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    parviz rezvani moghadam

    2009-06-01

    Full Text Available In order to study the effects of different irrigation intervals and plant density on morphological characteristics, grain and oil yields of sesame, an experiment was conducted at experimental station, college of agriculture, Ferdowsi University of Mashhad. Four different irrigation intervals (one, two, three and four weeks with four plant densities (20, 30, 40 and 50 plants/m2 were compared in a spilt plot arrangement based on randomized complete block design with four replications. Irrigation intervals and plant densities allocated in main plots and subplots, respectively. Different characteristics such as plant height, distance of first capsule from soil surface, number of branches per plant, number of grains per capsule, number of capsules per plant, grain yield, 1000-seed weight, harvest index and oil yield were recorded. The results showed that there were no significant difference between different irrigation intervals in terms of distance of first capsule from soil surface, number of grains per capsule, 1000-seed weight and harvest index. Different irrigation intervals had significant effects on plant height, number of branches per plant, number of capsules per plant, grain yield and oil yield. There were significant differences between different plant densities in terms of distance of first capsule from soil surface, number of branches per plant, number of graines per capsule, number of capsules per plant, grain yield, harvest index and oil yield. The highest grain yield (798/7 kg/ha and oil yield (412/8 kg/ha were obtained at one week and four weeks irrigation intervals, respectively. Between all treatments, 50 plants/m2 and one week irrigation interval produced the highest grain yield (914/7 kg/ha and oil yield (478/6 kg/ha. Because of shortage of water in Mashhad condition, the results recommended that, 50 plants/m2 and two weeks irrigation interval produced rather acceptable grain yield, with less water consumption.

  1. Plasticity in stomatal size and density of potato leaves under different irrigation and phosphorus regimes.

    Science.gov (United States)

    Sun, Yanqi; Yan, Fei; Cui, Xiaoyong; Liu, Fulai

    2014-09-01

    The morphological features of stomata including their size and density could be modulated by environmental cues; however, the underlying mechanisms remain largely elusive. Here, the effect of different irrigation and phosphorus (P) regimes on stomatal size (SS) and stomatal density (SD) of potato leaves was investigated. The plants were grown in split-root pots under two P fertilization rates (viz., 0 and 100mgkg(-1) soil, denoted as P0 and P1, respectively) and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation regimes. Results showed that SS and SD were unresponsive to P but significantly affected by the irrigation treatment. FI plants had the largest SS, followed by DI, and PRD the smallest; and the reverse was the case for SD. Compared to FI and DI, PRD plants had significantly lower values of specific leaf area (SLA) and leaf carbon isotope discrimination (Δ(13)C) under P0. Midday leaf water potential (Ψleaf) and stomatal conductance (gs) was similar for DI and PRD, which was significantly lower than that of FI. Leaf contents of C, N, K, Ca and Mg were higher in PRD than in DI plants, particularly under P0. When analyzed across the three irrigation regimes, it was found that the P1 plants had significantly higher leaf contents of P and Mg, but significantly lower leaf K content compared to the P0 plants. Linear correlation analyses revealed that SS was positively correlated with Ψleaf and Δ(13)C; whereas SD was negatively correlated with Ψleaf, Δ(13)C and SLA, and positively correlated with leaf C, N and Ca contents. And gs was positively correlated with SS but negatively correlated with SD. Collectively, under low P level, the smaller and denser stomata in PRD plants may bring about a more efficient stomatal control over gas exchange, hereby potentially enhance water-use efficiency as exemplified by the lowered leaf Δ(13)C under fluctuating soil moisture conditions. Copyright © 2014 Elsevier GmbH. All rights reserved.

  2. Charge density fluctuation of low frequency in a dusty plasma

    Institute of Scientific and Technical Information of China (English)

    李芳; 吕保维; O.Havnes

    1997-01-01

    The charge density fluctuation of low frequency in a dusty plasma, which is derived from the longitudinal dielectric permittivity of the dusty plasma, has been studied by kinetic theory. The results show that the P value, which describes the relative charge density on the dust in the plasma, and the charging frequency of a dust particle Ωc, which describes the ratio of charge changing of the dust particles, determine the character of the charge density fluctuation of low frequency. For a dusty plasma of P<<1, when the charging frequency Ωc is much smaller than the dusty plasma frequency wd, there is a strong charge density fluctuation which is of character of dust acoustic eigen wave. For a dusty plasma of P>>1, when the frequency Ωc, is much larger than wd there are weaker fluctuations with a wide spectrum. The results have been applied to the ionosphere and the range of radius and density of dust particles is found, where a strong charge density fluctuation of low frequency should exist.

  3. Control of soil moisture with radio frequency in a photovoltaic-powered drip irrigation system

    OpenAIRE

    DURSUN, Mahir; ÖZDEN, Semih

    2015-01-01

    Solar-powered irrigation systems are becoming increasingly widespread. However, the initial setup costs of these systems are very high. To reduce these costs, both the energy usage and the prevention of losses from irrigation systems are very important. In this study, a drip irrigation control system of 1000 dwarf cherry trees was controlled using soil moisture sensors in order to prevent excessive water consumption and energy losses in a solar-powered irrigation system. The control sys...

  4. Distribution Of 15N Fertilizer Added To Sandy Soil Under Drip Irrigation System As Affected By Irrigation Frequencies

    International Nuclear Information System (INIS)

    GADALLA, A.M.; GALAL, Y.G.M.; EL-GENDY, R.W.; ISMAIL, M.M.; EL-DEGWY, S.M.; KASSAB, M.F.

    2009-01-01

    Neutron moisture meter and stable nitrogen isotope ( 15 N) were used to follow horizontal and vertical water movement and N-fertilizer added to soil before and after irrigation. The data indicated that soil moisture distribution and values of total hydraulic potential depend on soil moisture content. Characterization of nitrogen in soil for all sites around the emitter indicated spatial variability with different soil depths due to leaching and volatilization processes. Moreover, water movement and flow direction greatly were characterized by active evaporation depth which was 30 cm.

  5. High frequency characterization of Galfenol minor flux density loops

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    Ling Weng

    2017-05-01

    Full Text Available This paper presents the first measurement of ring-shaped Galfenol’s high frequency-dependent minor flux density loops. The frequencies of applied AC magnetic field are 1k, 5k, 10k, 50k, 100k, 200k, 300k, 500 kHz. The measurements show that the cycle area between the flux density and magnetic field curves increase with increasing frequency. High frequency-dependent characterization, including coercivity, specific power loss, residual induction, and maximum relative permeability are discussed. Minor loops for different max induction are also measured and discussed at the same frequency 100 kHz. Minor loops with the same max induction 0.05 T for different frequencies 50, 100, 200, 300, 400 kHz are measured and specific power loss are discussed.

  6. Effect of different irrigation frequencies on growth and yield of different wheat genotypes in Sindh

    International Nuclear Information System (INIS)

    Khokhar, B.; Hussain, I.

    2010-01-01

    Irrigation at critical growth stages could improve wheat yield significantly. A study was conducted during 2000-2002 to determine effect of different irrigation levels on growth and yield of different wheat genotypes in the province of Sindh. The trial was laid out in split block design at Wheat Research Institute, Sindh, Sakrand, in which four irrigation treatments I3 (irrigation at crown root, booting and soft dough stage), I4 (irrigation at crown root, tillering, booting and soft dough stage), I5 (irrigation at crown root, tillering, booting, anthesis and soft dough stage) and I6 (irrigation at crown root, tillering, booting, anthesis, soft dough and hard dough stage) were in blocks and six wheat genotypes; V-7001, V-7002, V-7004, NARC-9 and CO-9043 and Abadgar-93 were planted. Number of irrigation did not have any significant effect on plant height, whereas plant height was affected significantly in different cultivars. Application of five irrigations at different wheat growth stages resulted in higher spike length, higher number of grains and wheat grain yield. Wheat variety Abadgar-93 and V-7004, had taller plants in comparison with cultivars NARC-9 and V-7004 however, wheat grain yield was not affected significantly among different cultivars. (author)

  7. Response of lettuce to Cd-enriched water and irrigation frequencies ...

    African Journals Online (AJOL)

    Also, shoot Cd content showed a significant positive correlation with the final accumulated Cd concentration of soil and was expressed by a plateau model under the dry irrigation regime and linear models at other irrigation intervals. Overall, shoot Cd concentration was predicted by using a simple linear regression model ...

  8. The frequency-domain approach for apparent density mapping

    Science.gov (United States)

    Tong, T.; Guo, L.

    2017-12-01

    Apparent density mapping is a technique to estimate density distribution in the subsurface layer from the observed gravity data. It has been widely applied for geologic mapping, tectonic study and mineral exploration for decades. Apparent density mapping usually models the density layer as a collection of vertical, juxtaposed prisms in both horizontal directions, whose top and bottom surfaces are assumed to be horizontal or variable-depth, and then inverts or deconvolves the gravity anomalies to determine the density of each prism. Conventionally, the frequency-domain approach, which assumes that both top and bottom surfaces of the layer are horizontal, is usually utilized for fast density mapping. However, such assumption is not always valid in the real world, since either the top surface or the bottom surface may be variable-depth. Here, we presented a frequency-domain approach for apparent density mapping, which permits both the top and bottom surfaces of the layer to be variable-depth. We first derived the formula for forward calculation of gravity anomalies caused by the density layer, whose top and bottom surfaces are variable-depth, and the formula for inversion of gravity anomalies for the density distribution. Then we proposed the procedure for density mapping based on both the formulas of inversion and forward calculation. We tested the approach on the synthetic data, which verified its effectiveness. We also tested the approach on the real Bouguer gravity anomalies data from the central South China. The top surface was assumed to be flat and was on the sea level, and the bottom surface was considered as the Moho surface. The result presented the crustal density distribution, which was coinciding well with the basic tectonic features in the study area.

  9. Low-frequency oscillations at high density in JFT-2

    International Nuclear Information System (INIS)

    Maeno, Masaki; Katagiri, Masaki; Suzuki, Norio; Fujisawa, Noboru

    1977-12-01

    Low-frequency oscillations in a plasma were measured with magnetic probes and Si surface-barrier detectors, and behaviour of the high density plasmas was studied. The plasma current profile in the phase of decreasing density after the interruption of gas input is more peaked than during gas input. The introduction of hydrogen during a discharge results in a reduction of the impurities flux. The increase of density by fast gas input is limited with a negative voltage spike. Immediately before a negative voltage spike, oscillations of m=1,2 grow, leading to the spike. (auth.)

  10. Management of irrigation frequency and nitrogen fertilization to mitigate GHG and NO emissions from drip-fertigated crops

    Energy Technology Data Exchange (ETDEWEB)

    Abalos, Diego, E-mail: diego.abalos@upm.es [ETSI Agronomos, Technical University of Madrid, Ciudad Universitaria, 28040 Madrid (Spain); Sanchez-Martin, Laura; Garcia-Torres, Lourdes [ETSI Agronomos, Technical University of Madrid, Ciudad Universitaria, 28040 Madrid (Spain); Groenigen, Jan Willem van [Department of Soil Quality, Wageningen University, PO Box 47, 6700 AA Wageningen (Netherlands); Vallejo, Antonio [ETSI Agronomos, Technical University of Madrid, Ciudad Universitaria, 28040 Madrid (Spain)

    2014-08-15

    Drip irrigation combined with split application of fertilizer nitrogen (N) dissolved in the irrigation water (i.e. drip fertigation) is commonly considered best management practice for water and nutrient efficiency. As a consequence, its use is becoming widespread. Some of the main factors (water-filled pore space, NH{sub 4}{sup +} and NO{sub 3}{sup −}) regulating the emissions of greenhouse gases (i.e. N{sub 2}O, CO{sub 2} and CH{sub 4}) and NO from agroecosystems can easily be manipulated by drip fertigation without yield penalties. In this study, we tested management options to reduce these emissions in a field experiment with a melon (Cucumis melo L.) crop. Treatments included drip irrigation frequency (weekly/daily) and type of N fertilizer (urea/calcium nitrate) applied by fertigation. Crop yield, environmental parameters, soil mineral N concentrations and fluxes of N{sub 2}O, NO, CH{sub 4} and CO{sub 2} were measured during 85 days. Fertigation with urea instead of calcium nitrate increased N{sub 2}O and NO emissions by a factor of 2.4 and 2.9, respectively (P < 0.005). Daily irrigation reduced NO emissions by 42% (P < 0.005) but increased CO{sub 2} emissions by 21% (P < 0.05) compared with weekly irrigation. We found no relation between irrigation frequency and N{sub 2}O emissions. Based on yield-scaled Global Warming Potential as well as NO cumulative emissions, we conclude that weekly fertigation with a NO{sub 3}{sup −}-based fertilizer is the best option to combine agronomic productivity with environmental sustainability. Our study shows that adequate management of drip fertigation, while contributing to the attainment of water and food security, may provide an opportunity for climate change mitigation. - Highlights: • The effect of fertigation management techniques on GHG and NO emissions was studied. • Fertigation with urea instead of calcium nitrate increased N{sub 2}O by a factor of 2.4. • Daily irrigation reduced NO (42%) but increased CO

  11. Modal density of rectangular structures in a wide frequency range

    Science.gov (United States)

    Parrinello, A.; Ghiringhelli, G. L.

    2018-04-01

    A novel approach to investigate the modal density of a rectangular structure in a wide frequency range is presented. First, the modal density is derived, in the whole frequency range of interest, on the basis of sound transmission through the infinite counterpart of the structure; then, it is corrected by means of the low-frequency modal behavior of the structure, taking into account actual size and boundary conditions. A statistical analysis reveals the connection between the modal density of the structure and the transmission of sound through its thickness. A transfer matrix approach is used to compute the required acoustic parameters, making it possible to deal with structures having arbitrary stratifications of different layers. A finite element method is applied on coarse grids to derive the first few eigenfrequencies required to correct the modal density. Both the transfer matrix approach and the coarse grids involved in the finite element analysis grant high efficiency. Comparison with alternative formulations demonstrates the effectiveness of the proposed methodology.

  12. Nonlinear low-frequency wave aspect of foreshock density holes

    Directory of Open Access Journals (Sweden)

    N. Lin

    2008-11-01

    Full Text Available Recent observations have uncovered short-duration density holes in the Earth's foreshock region. There is evidence that the formation of density holes involves non-linear growth of fluctuations in the magnetic field and plasma density, which results in shock-like boundaries followed by a decrease in both density and magnetic field. In this study we examine in detail a few such events focusing on their low frequency wave characteristics. The propagation properties of the waves are studied using Cluster's four point observations. We found that while these density hole-structures were convected with the solar wind, in the plasma rest frame they propagated obliquely and mostly sunward. The wave amplitude grows non-linearly in the process, and the waves are circularly or elliptically polarized in the left hand sense. The phase velocities calculated from four spacecraft timing analysis are compared with the velocity estimated from δEB. Their agreement justifies the plane electromagnetic wave nature of the structures. Plasma conditions are found to favor firehose instabilities. Oblique Alfvén firehose instability is suggested as a possible energy source for the wave growth. Resonant interaction between ions at certain energy and the waves could reduce the ion temperature anisotropy and thus the free energy, thereby playing a stabilizing role.

  13. Nonlinear low-frequency wave aspect of foreshock density holes

    Directory of Open Access Journals (Sweden)

    N. Lin

    2008-11-01

    Full Text Available Recent observations have uncovered short-duration density holes in the Earth's foreshock region. There is evidence that the formation of density holes involves non-linear growth of fluctuations in the magnetic field and plasma density, which results in shock-like boundaries followed by a decrease in both density and magnetic field. In this study we examine in detail a few such events focusing on their low frequency wave characteristics. The propagation properties of the waves are studied using Cluster's four point observations. We found that while these density hole-structures were convected with the solar wind, in the plasma rest frame they propagated obliquely and mostly sunward. The wave amplitude grows non-linearly in the process, and the waves are circularly or elliptically polarized in the left hand sense. The phase velocities calculated from four spacecraft timing analysis are compared with the velocity estimated from δE/δB. Their agreement justifies the plane electromagnetic wave nature of the structures. Plasma conditions are found to favor firehose instabilities. Oblique Alfvén firehose instability is suggested as a possible energy source for the wave growth. Resonant interaction between ions at certain energy and the waves could reduce the ion temperature anisotropy and thus the free energy, thereby playing a stabilizing role.

  14. Effects of irrigation frequency and grit color on the germination of lodgepole pine seeds

    Science.gov (United States)

    Jeremy R. Pinto; R. Kasten Dumroese; Douglas R. Cobos

    2009-01-01

    Nursery cultural practices during germination can be highly variable between existing production facilities. Although nursery guidebooks suggest keeping seeds moist, there are no known scientific answers indicating what sufficient moisture levels are. This study objective was to characterize differing irrigation regimes and grit color choices on different germination...

  15. Modeling root length density of field grown potatoes under different irrigation strategies and soil textures using artificial neural networks

    DEFF Research Database (Denmark)

    Ahmadi, Seyed Hamid; Sepaskhah, Ali Reza; Andersen, Mathias Neumann

    2014-01-01

    ) of the eight input variables: soil layer intervals (D), percentages of sand (Sa), silt (Si), and clay (Cl), bulk density of soil layers (Bd), weighted soil moisture deficit during the irrigation strategies period (SMD), geometric mean particle size diameter (dg), and geometric standard deviation (σg......). The results of the study showed that all the nine ANN models predicted the target RLD values satisfactorily with a correlation coefficient R2>0.98. The simplest and most complex ANN architectures were 3:2:1 and 5:5:1 consisting of D, SMD, dg, and D, Bd, SMD, σg, dg as the input variables, respectively. Low...

  16. Influence of driving frequency on oxygen atom density in O2 radio frequency capacitively coupled plasma

    International Nuclear Information System (INIS)

    Kitajima, Takeshi; Noro, Kouichi; Nakano, Toshiki; Makabe, Toshiaki

    2004-01-01

    The influence of the driving frequency on the absolute oxygen atom density in an O 2 radio frequency (RF) capacitively coupled plasma (CCP) was investigated using vacuum ultraviolet absorption spectroscopy with pulse modulation of the main plasma. A low-power operation of a compact inductively coupled plasma light source was enabled to avoid the significant measurement errors caused by self-absorption in the light source. The pulse modulation of the main plasma enabled accurate absorption measurement for high plasma density conditions by eliminating background signals due to light emission from the main plasma. As for the effects of the driving frequency, the effect of VHF (100 MHz) drive on oxygen atom production was small because of the modest increase in plasma density of electronegative O 2 in contrast to the significant increase in electron density previously observed for electropositive Ar. The recombination coefficient of oxygen atoms on the electrode surface was obtained from a decay rate in the afterglow by comparison with a diffusion model, and it showed agreement with previously reported values for several electrode materials

  17. Extended Opacity Tables with Higher Temperature-Density-Frequency Resolution

    Science.gov (United States)

    Schillaci, Mark; Orban, Chris; Delahaye, Franck; Pinsonneault, Marc; Nahar, Sultana; Pradhan, Anil

    2015-05-01

    Theoretical models for plasma opacities underpin our understanding of radiation transport in many different astrophysical objects. These opacity models are also relevant to HEDP experiments such as ignition scale experiments on NIF. We present a significantly expanded set of opacity data from the widely utilized Opacity Project, and make these higher resolution data publicly available through OSU's portal with dropbox.com. This expanded data set is used to assess how accurate the interpolation of opacity data in temperature-density-frequency dimensions must be in order to adequately model the properties of most stellar types. These efforts are the beginning of a larger project to improve the theoretical opacity models in light of experimental results at the Sandia Z-pinch showing that the measured opacity of Iron disagrees strongly with all current models.

  18. Laser line shape and spectral density of frequency noise

    International Nuclear Information System (INIS)

    Stephan, G.M.; Blin, S.; Besnard, P.; Tam, T.T.; Tetu, M.

    2005-01-01

    Published experimental results show that single-mode laser light is characterized in the microwave range by a frequency noise which essentially includes a white part and a 1/f (flicker) part. We theoretically show that the spectral density (the line shape) which is compatible with these results is a Voigt profile whose Lorentzian part or homogeneous component is linked to the white noise and the Gaussian part to the 1/f noise. We measure semiconductor laser line profiles and verify that they can be fit with Voigt functions. It is also verified that the width of the Lorentzian part varies like 1/P where P is the laser power while the width of the Gaussian part is more of a constant. Finally, we theoretically show from first principles that laser line shapes are also described by Voigt functions where the Lorentzian part is the laser Airy function and the Gaussian part originates from population noise

  19. Thermal performance of different planting substrates and irrigation frequencies in extensive tropical rooftop greeneries

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yi-Jiung [Department of Environmental Engineering and Science, Foo-Yin University, Kaohsiung (China); No. 16, Lane 29, Chen-Sing 7th Street, Niao-Song, Kaohsiung 833 (China); Lin, Hsien-Te [Department of Architecture, National Cheng Kung University, Tainan (China); No. 1, Ta-Hsueh Road, Tainan 701 (China)

    2011-02-15

    The need for the better use of scarce planetary resources has never been more evident than it is today. However, this need is poorly reflected in human housing. In recent years, there has been a growing realization of the importance of constructing human shelters that better conserve energy and water through appropriate insulation and architectural designs. Among the important advancements in these areas is the use of rooftop greeneries for both energy and water conservation. This paper performs an investigation into this topic within the specific climatic context of tropical regions. Long-term experimental results are provided from a four-floor building in Kaohsiung in the southern part of Taiwan. The study involves a fully monitored extensive rooftop greenery and examines four different plant substrates, three different irrigation regimes, and different types of drought-enduring plants to find the most efficient combination of all three in providing maximum heat insulation and water usage efficiency. The attenuation of solar radiation through the vegetation layer is evaluated, as well as the thermal insulation performance of the rooftop greenery structure. Among the substrates, burned sludge has the best thermal reduction percentage of heat amplitude under the roof slab surface (up to 84.4%). Irrigation twice a week has the best thermal reduction percentage of heat amplitude (91.6%). Among the plant types, Sansevieria trifasciata cv. Laurentii Compacta and Rhoeo spathaceo cv. Compacta are found to be suitable for extensive rooftop greeneries because they have the best coverage ratio and are most drought enduring. (author)

  20. Radio-frequency slurry-density measurement for dredging pipelines

    NARCIS (Netherlands)

    van Eeten, M.J.C.

    2011-01-01

    Hydraulic dredgers make use of a density meter to measure the instantaneous density in the slurry transport pipeline, primarily for process control and production calculation. the current ‘golden’ standard for slurry density measurement is the radioactive density meter. It is based on a slurry

  1. Frequency inverter and irrigation management in irrigated perimeter on Jaiba region - MG, Brazil; Uso de inversor de frequencia e do manejo da irrigacao em perimetro da regiao do Jaiba, MG

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, Maria Joselma de; Oliveira Filho, Delly; Vieira, Gustavo H.S. [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Engenharia Agricola], Emails: maria.moraes@ufv.br, delly@ufv.br, ghsvieira@ifes.edu.br; Scarcelli, Ricardo de O.C. [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Engenharia Eletrica], E-mail: rocvenceslau@yahoo.com.br

    2010-07-01

    The electric energy expenditure and the irrigation depth for one irrigated perimeter on Jaiba region/MG, Brazil, for the cultures: pineapple, banana, guava, lemon, papaya, mango, passion fruit, cantaloupe, pine cone and grape. With the monthly irrigation depth data for an hypothetical area of 12 lots (10 ha each), it was simulated, with Galateia software, the head pressure for 4 combinations of cultures: first - papaya (12 lots); second - banana (8 lots), guava (1), papaya (1), mango (1) and passion fruit (1); third - papaya (8), guava (1), pineapple (1), (1) and lemon (1); and fourth - guava (8), mango (1), papaya (1), pine cone (1) and passion fruit (1). It was dimensioned the necessary power and the electrical energy expenses with TOU (green category tariff) for the biggest irrigation depth. The frequency inverter use and the management of the number of working hours were simulated for each combination, in order to maximize the motor's load and the pump-motor set performance. For the combinations 2, 3, and 4 occurred reduction on the electrical energy consumption of 6%, 8% and 20%, respectively in respect of the combination 1. (author)

  2. High density terahertz frequency comb produced by coherent synchrotron radiation

    Science.gov (United States)

    Tammaro, S.; Pirali, O.; Roy, P.; Lampin, J.-F.; Ducournau, G.; Cuisset, A.; Hindle, F.; Mouret, G.

    2015-07-01

    Frequency combs have enabled significant progress in frequency metrology and high-resolution spectroscopy extending the achievable resolution while increasing the signal-to-noise ratio. In its coherent mode, synchrotron radiation is accepted to provide an intense terahertz continuum covering a wide spectral range from about 0.1 to 1 THz. Using a dedicated heterodyne receiver, we reveal the purely discrete nature of this emission. A phase relationship between the light pulses leads to a powerful frequency comb spanning over one decade in frequency. The comb has a mode spacing of 846 kHz, a linewidth of about 200 Hz, a fractional precision of about 2 × 10-10 and no frequency offset. The unprecedented potential of the comb for high-resolution spectroscopy is demonstrated by the accurate determination of pure rotation transitions of acetonitrile.

  3. Management of irrigation frequency and nitrogen fertilization to mitigate GHG and NO emissions from drip-fertigated crops

    NARCIS (Netherlands)

    Abalos, D.; Sanchez-Martin, L.; Garcia-Torres, L.; Groenigen, van J.W.; Vallejo, A.

    2014-01-01

    Drip irrigation combined with split application of fertilizer nitrogen (N) dissolved in the irrigation water (i.e. drip fertigation) is commonly considered best management practice for water and nutrient efficiency. As a consequence, its use is becoming widespread. Some of the main factors

  4. Response of Biomass Development, Essential Oil, and Composition of Plectranthus amboinicus (Lour.) Spreng. to Irrigation Frequency and Harvest Time.

    Science.gov (United States)

    Sabra, Ali S; Astatkie, Tessema; Alataway, Abed; Mahmoud, Abeer A; Gendy, Ahmed S H; Said-Al Ahl, Hussein A H; Tkachenko, Kirill G

    2018-03-01

    A greenhouse experiment was conducted to study the effects of four irrigation intervals (4, 8, 12, and 16 days) and six harvests (2, 4, 6, 8, 10, and 12 months after transplanting) on biomass, essential oil content, and composition of Plectranthus amboinicus (Lour.) Spreng. Fresh weight and essential oil yield decreased with increasing irrigation interval; whereas, essential oil content was stimulated by water stress and increased as the irrigation interval increased. Fresh weight of Plectranthus amboinicus irrigated every 4 days peaked when harvested at 6 months, but essential oil content peaked when irrigated every 16 days and harvested at 2 months after transplantation. On the other hand, essential oil yield peaked when irrigated every 8 days and harvested at 6 months. Thymol, p-cymene, γ-terpinene, and β-caryophyllene were the major compounds, and they peaked at different irrigation intervals and harvest times. This study showed biomass, essential oil content, and yield as well as the major and minor constituents of Plectranthus amboinicus are influenced by irrigation interval and the timing of harvest. © 2018 Wiley-VHCA AG, Zurich, Switzerland.

  5. The Influence of Orthographic Neighborhood Density and Word Frequency on Visual Word Recognition: Insights from RT Distributional Analyses

    Directory of Open Access Journals (Sweden)

    Stephen Wee Hun eLim

    2016-03-01

    Full Text Available The effects of orthographic neighborhood density and word frequency in visual word recognition were investigated using distributional analyses of response latencies in visual lexical decision. Main effects of density and frequency were observed in mean latencies. Distributional analyses, in addition, revealed a density x frequency interaction: for low-frequency words, density effects were mediated predominantly by distributional shifting whereas for high-frequency words, density effects were absent except at the slower RTs, implicating distributional skewing. The present findings suggest that density effects in low-frequency words reflect processes involved in early lexical access, while the effects observed in high-frequency words reflect late postlexical checking processes.

  6. On the locus and spread of pseudo-density functions in the time-frequency plane

    NARCIS (Netherlands)

    Janssen, A.J.E.M.

    1982-01-01

    Various time-frequency pseudo-density functions used in signal analysis are compared with respect to spread. Among the members of Cohen's class of pseudo-density functions satisfying the finite support property as well as Moyal's formula, the Wigner distribution is the most well-behaved one in the

  7. Diagnosis of Unmagnetized Plasma Electron Number Density and Electron-neutral Collision Frequency by Using Microwave

    International Nuclear Information System (INIS)

    Yuan Zhongcai; Shi Jiaming; Xu Bo

    2005-01-01

    The plasma diagnostic method using the transmission attenuation of microwaves at double frequencies (PDMUTAMDF) indicates that the frequency and the electron-neutral collision frequency of the plasma can be deduced by utilizing the transmission attenuation of microwaves at two neighboring frequencies in a non-magnetized plasma. Then the electron density can be obtained from the plasma frequency. The PDMUTAMDF is a simple method to diagnose the plasma indirectly. In this paper, the interaction of electromagnetic waves and the plasma is analyzed. Then, based on the attenuation and the phase shift of a microwave in the plasma, the principle of the PDMUTAMDF is presented. With the diagnostic method, the spatially mean electron density and electron collision frequency of the plasma can be obtained. This method is suitable for the elementary diagnosis of the atmospheric-pressure plasma

  8. Studying Geographical Distribution Map of Weeds of Irrigated Wheat Fields of Ardabil Province

    OpenAIRE

    B Soheili

    2013-01-01

    In order to identify the density and abundance of weeds in irrigated wheat fields of Ardabil Province, 76 samples of irrigated wheat fields based on cultivation area from all counties of Ardabil province for six years (2001-2006) were selected. The genus and species of weeds from each sampling fields and their population indices density, frequency and uniformity of each species were calculated by using Thomas method. Geographic coordinates of field (Latitude, Altitude and Elevation) were the ...

  9. Water and radiation use efficiencies of transplanted rice (Oryza sativa L.) at different plant densities and irrigation regimes under semi-arid environment

    International Nuclear Information System (INIS)

    Ahmad, S.; Ali, H.; Shad, S.A.; Zia-ul-Haq, M.; Ahmad, A.; Maqsood, M.; Khan, M.B.; Mehmood, S.; Hussain, A.

    2008-01-01

    Growth and yield of rice (Oryza sativa L.), in response to plant densities and irrigation (optimum to stress) were analyzed in terms of interception and utilization of photo-synthetically active radiation (PAR) and water use efficiency (WUE). The amount of PAR intercepted and cumulative evapotranspiration (ET) by each treatment was estimated from the measured leaf area index. The relationships between total dry matter grain yield and accumulated intercepted PAR and cumulative ET were linear. Yield differences among the treatments were attributed to the amount of PAR intercepted and water transpired their efficiencies of utilization or both. The fraction of intercepted radiation and WUE was significantly affected by the plant densities and various irrigation regimes, while, radiation utilization efficiency (RUE) and water use efficiency (WUE) for TDM varied from 1.15 g MJ-1 to 1.36 g MJ-1 and 22.6 kg per ha mm-1 to 24.3 kg per ha mm-1 during both the seasons

  10. Evaluation of superabsorbent efficiency in response to dehydration frequencies, salinity and temperature and its effect on yield and quality of cotton under deficit irrigation

    Directory of Open Access Journals (Sweden)

    Hamid-Reza Fallahi

    2016-03-01

    Full Text Available Introduction Reduced availability of water resources in many arid countries including Iran, particularly in response to the indiscriminate harvesting of water reservoirs and climate change, has created concerns. Therefore, the sustainable use of water resources especially in agriculture is a necessity for these countries. Strategies such as deficit irrigation and superabsorbent application are two important ways for improving water use efficiency in agricultural lands. In deficit irrigation the crop must be irrigated less than its required water. Therefore, some reduction may occur in crop yield, but the savings in water will improve the water use efficiency (Akbari Nodehi, 2011. Superabsorbent polymers also increase the nutrients and water holding capacity of soil for a long time and thereby reduce crop water requirement. However, the effectiveness of these materials could be affected by dehydration frequencies, temperature and irrigation water quality (Karimi et al., 2009. Due to the limitation of water resources in many parts of Iran, the aim of this study was to investigate the possibility of cotton production under deficit irrigation along with application of different rates of superabsorbent. In addition, simulation of superabsorbent efficiency at different levels of salinity, temperature and dehydration frequencies (swelling and de-swelling were the other objectives in this study. Materials and methods 1. Laboratory experiments In these experiments the effects of temperature (4, 10, 20, 30 and 40 °C, salinity (0, 0.25, 0.5, 0.75 and 1% NaCl solutions at two temperatures of 10 and 25°C and frequency of partial dehydration (from 1 to 5 stages watering and 70% dewatering were simulated on water absorption capacity of superabsorbent polymer at laboratory of environmental stresses, Sarayan Faculty of Agriculture, Birjand University. 2- Field experiment This experiment was designed at Research Station of Sarayan Faculty of Agriculture

  11. Frequency-resolved interferometric measurement of local density fluctuations for turbulent combustion analysis

    International Nuclear Information System (INIS)

    Köberl, S; Giuliani, F; Woisetschläger, J; Fontaneto, F

    2010-01-01

    A validation of a novel interferometric measurement technique for the frequency-resolved detection of local density fluctuation in turbulent combustion analysis was performed in this work. Two laser vibrometer systems together with a signal analyser were used to obtain frequency spectra of density fluctuations across a methane-jet flame. Since laser vibrometry is based on interferometric techniques, the derived signals are path-integrals along the measurement beam. To obtain local frequency spectra of density fluctuations, long-time-averaged measurements from each of the two systems were performed using correlation functions and cross spectra. Results were compared to data recorded by standard interferometric techniques for validation purposes. Additionally, Raman scattering and laser Doppler velocimetry were used for flame characterization

  12. Collision frequency of Lennard–Jones fluids at high densities by ...

    Indian Academy of Sciences (India)

    Detailed classical molecular dynamics simulation of transport coefficients and collision frequencies at high densities in rare gases are presented in this paper with a view to investigate the likely cause of discrepancy between theory and experiments. The results, when compared with experiments, showed an ...

  13. Accuracy of finite-difference harmonic frequencies in density functional theory.

    Science.gov (United States)

    Liu, Kuan-Yu; Liu, Jie; Herbert, John M

    2017-07-15

    Analytic Hessians are often viewed as essential for the calculation of accurate harmonic frequencies, but the implementation of analytic second derivatives is nontrivial and solution of the requisite coupled-perturbed equations engenders a sizable memory footprint for large systems, given that these equations are not required for energy and gradient calculations in density functional theory. Here, we benchmark the alternative approach to harmonic frequencies based on finite differences of analytic first derivatives, a procedure that is amenable to large-scale parallelization. Not only for absolute frequencies but also for isotopic and conformer-dependent frequency shifts in flexible molecules, we find that the finite-difference approach exhibits mean errors numbers. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  14. High frequency electric field spikes formed by electron beam-plasma interaction in plasma density gradients

    International Nuclear Information System (INIS)

    Gunell, H.; Loefgren, T.

    1997-02-01

    In the electron beam-plasma interaction at an electric double layer the beam density is much higher than in the classical beam-plasma experiments. The wave propagation takes place along the density gradient, that is present at the high potential side of the double layer. Such a case is studied experimentally by injecting the electron beam from a plane cathode, without any grids suppressing the gradient, and by particle simulations. The high frequency field concentrates in a sharp 'spike' with a half width of the order of one wavelength. The spike is found to be a standing wave surrounded by regions dominated by propagating waves. It forms at a position where its frequency is close to the local plasma frequency. The spike forms also when the electric field is well below the threshold for modulational instability, and long before a density cavity is formed in the simulations. Particle simulations reveal that, at the spike, there is a backward travelling wave that, when it is strongly damped, accelerates electrons back towards the cathode. In a simulation of a homogeneous plasma without the density gradient no spike is seen, and the wave is purely travelling instead of standing. 9 refs

  15. Anisotropic frequency response of critical density fluctuation of NIPA gel under oscillation shear

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Masaaki [Research Reactor Institute, Kyoto University, Osaka 590-0494 (Japan)]. E-mail: sugiyama@rri.kyoto-u.ac.jp; Vigild, Martin E. [Danish Polymer Centre, Technical University of Denmark, 2800 Lyngby (Denmark); Fukunaga, Toshiharu [Research Reactor Institute, Kyoto University, Osaka 590-0494 (Japan); Itoh, Keiji [Research Reactor Institute, Kyoto University, Osaka 590-0494 (Japan); Mori, Kazuhiro [Research Reactor Institute, Kyoto University, Osaka 590-0494 (Japan); Sato, Takashi [Department of Engineering Physics and Mechanics, Kyoto University, Kyoto 606-8501 (Japan); Annaka, Masahiko [Department of Chemistry, Kyushu University, Fukuoka 812-8581 (Japan)

    2006-11-15

    A relation between rheology and structure of high density NIPA gel around a critical point on volume phase transition was studied by a simultaneous rheology and small-angle neutron scattering measurement. Just below the critical temperature, the NIPA gel showed softening: G{sup '} and G{sup '}' get closer (G{sup '}>G{sup '}'). At this temperature, the density fluctuation enhanced along the shear direction corresponding to the shear frequency but not to the shear strength. It means that this anisotropy is different from that observed in a statically stretched gel.

  16. CLIMATIC SIGNALS FROM INTRA-ANNUAL DENSITY FLUCTUATION FREQUENCY IN MEDITERRANEAN PINES AT A REGIONAL SCALE

    Directory of Open Access Journals (Sweden)

    Enrica eZalloni

    2016-05-01

    Full Text Available Tree rings provide information about the climatic conditions during the growing season by recording them in different anatomical features, such as Intra-Annual Density Fluctuations (IADFs. IADFs are intra-annual changes of wood density appearing as latewood-like cells within earlywood, or earlywood-like cells within latewood. The occurrence of IADFs is dependent on the age and size of the tree, and it is triggered by climatic drivers. The variations of IADF frequency of different species and their dependence on climate across a wide geographical range have still to be explored. The objective of this study is to investigate the effect of age, tree-ring width and climate on IADF formation and frequency at a regional scale across the Mediterranean Basin in Pinus halepensis Mill., Pinus pinaster Ait. and Pinus pinea L. The analyzed tree-ring network was composed of P. pinea trees growing at 11 sites (2 in Italy, 4 in Spain and 4 in Portugal, P. pinaster from 19 sites (2 in Italy, 13 in Spain and 4 in Portugal, and P. halepensis from 38 sites in Spain. The correlations between IADF frequency and monthly minimum, mean and maximum temperatures, as well as between IADF frequency and total precipitation, were analyzed. A significant negative relationship between IADF frequency and tree-ring age was found for the three Mediterranean pines. Moreover, IADFs were more frequent in wider rings than in narrower ones, although the widest rings showed a reduced IADF frequency. Wet conditions during late summer/early autumn triggered the formation of IADFs in the three species. Our results suggest the existence of a common climatic driver for the formation of IADFs in Mediterranean pines, highlighting the potential use of IADF frequency as a proxy for climate reconstructions with geographical resolution.

  17. Climatic Signals from Intra-annual Density Fluctuation Frequency in Mediterranean Pines at a Regional Scale

    Science.gov (United States)

    Zalloni, Enrica; de Luis, Martin; Campelo, Filipe; Novak, Klemen; De Micco, Veronica; Di Filippo, Alfredo; Vieira, Joana; Nabais, Cristina; Rozas, Vicente; Battipaglia, Giovanna

    2016-01-01

    Tree rings provide information about the climatic conditions during the growing season by recording them in different anatomical features, such as intra-annual density fluctuations (IADFs). IADFs are intra-annual changes of wood density appearing as latewood-like cells within earlywood, or earlywood-like cells within latewood. The occurrence of IADFs is dependent on the age and size of the tree, and it is triggered by climatic drivers. The variations of IADF frequency of different species and their dependence on climate across a wide geographical range have still to be explored. The objective of this study is to investigate the effect of age, tree-ring width and climate on IADF formation and frequency at a regional scale across the Mediterranean Basin in Pinus halepensis Mill., Pinus pinaster Ait., and Pinus pinea L. The analyzed tree-ring network was composed of P. pinea trees growing at 10 sites (2 in Italy, 4 in Spain, and 4 in Portugal), P. pinaster from 19 sites (2 in Italy, 13 in Spain, and 4 in Portugal), and P. halepensis from 38 sites in Spain. The correlations between IADF frequency and monthly minimum, mean and maximum temperatures, as well as between IADF frequency and total precipitation, were analyzed. A significant negative relationship between IADF frequency and tree-ring age was found for the three Mediterranean pines. Moreover, IADFs were more frequent in wider rings than in narrower ones, although the widest rings showed a reduced IADF frequency. Wet conditions during late summer/early autumn triggered the formation of IADFs in the three species. Our results suggest the existence of a common climatic driver for the formation of IADFs in Mediterranean pines, highlighting the potential use of IADF frequency as a proxy for climate reconstructions with geographical resolution. PMID:27200052

  18. Density and relative frequency effects on competitive interactions and resource use in pea–barley intercrops

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, H.; Andersen, H.K.; Jørnsgaard, B.

    2006-01-01

    or specific grain yield composition are wanted. Keywords: Competition dynamics; Grain quality; Hordeum vulgare; Intercropping; Nitrogen use; Organic farming; Pisum sativum; Weeds; Yield Abbreviations: IC, mixed intercropping; LER, land equivalent ratio; N, nitrogen; REIc, relative efficiency index; SC, sole...... not increase its reliance on atmospheric nitrogen fixation compared to the pea sole crop. With respect to soil nitrogen uptake there were no effect of plant density but a strong effect of the relative frequency of pea in the intercrop, the greater the proportion the lower the uptake. Changes in the competitive...... and tillering ability of barley are seen as likely explanations of lower weed load in the barley dominated crop treatments. This study points at the potential of employing density and relative crop frequency as "regulators" when specific intercrop objectives such as increased competitiveness towards weeds...

  19. Software Toolbox for Low-Frequency Conductivity and Current Density Imaging Using MRI.

    Science.gov (United States)

    Sajib, Saurav Z K; Katoch, Nitish; Kim, Hyung Joong; Kwon, Oh In; Woo, Eung Je

    2017-11-01

    Low-frequency conductivity and current density imaging using MRI includes magnetic resonance electrical impedance tomography (MREIT), diffusion tensor MREIT (DT-MREIT), conductivity tensor imaging (CTI), and magnetic resonance current density imaging (MRCDI). MRCDI and MREIT provide current density and isotropic conductivity images, respectively, using current-injection phase MRI techniques. DT-MREIT produces anisotropic conductivity tensor images by incorporating diffusion weighted MRI into MREIT. These current-injection techniques are finding clinical applications in diagnostic imaging and also in transcranial direct current stimulation (tDCS), deep brain stimulation (DBS), and electroporation where treatment currents can function as imaging currents. To avoid adverse effects of nerve and muscle stimulations due to injected currents, conductivity tensor imaging (CTI) utilizes B1 mapping and multi-b diffusion weighted MRI to produce low-frequency anisotropic conductivity tensor images without injecting current. This paper describes numerical implementations of several key mathematical functions for conductivity and current density image reconstructions in MRCDI, MREIT, DT-MREIT, and CTI. To facilitate experimental studies of clinical applications, we developed a software toolbox for these low-frequency conductivity and current density imaging methods. This MR-based conductivity imaging (MRCI) toolbox includes 11 toolbox functions which can be used in the MATLAB environment. The MRCI toolbox is available at http://iirc.khu.ac.kr/software.html . Its functions were tested by using several experimental datasets, which are provided together with the toolbox. Users of the toolbox can focus on experimental designs and interpretations of reconstructed images instead of developing their own image reconstruction softwares. We expect more toolbox functions to be added from future research outcomes. Low-frequency conductivity and current density imaging using MRI includes

  20. Desenvolvimento e produtividade do tomateiro sob diferentes freqüências de irrigação em estufa Tomato development and yield under different irrigation frequencies in greenhouse

    Directory of Open Access Journals (Sweden)

    Regina CM Pires

    2009-06-01

    Full Text Available O crescimento de plantas em substrato em cultivo protegido requer conhecimento técnico apropriado para uso racional e eficientede água e de nutrientes. O objetivo deste trabalho foi avaliar o efeito de seis freqüências de irrigação no desenvolvimento e na produção do tomateiro cultivado em ambiente protegido. O experimento foi conduzido em Campinas, de novembro de 2003 a abril de 2004. O delineamento experimental foi de blocos ao acaso com seis tratamentos e quatro repetições. Os tratamentos consistiram em seis freqüências de irrigação: cinco, quatro, três, duas, uma vez por dia e irrigação em dias alternados. A irrigação foi aplicada por gotejamento. O substrato utilizado foi o composto de fibra de coco. As freqüências de irrigação de uma, três, quatro e cinco vezes por dia resultaram nas maiores produções de frutos comerciáveis de tomateiro. O maior número e peso médio dos frutos foram obtidos nos tratamentos com freqüência de irrigação de uma, duas, três, quatro e cinco vezes por dia. As freqüências de irrigação de uma vez por dia e em dias alternados proporcionaram maior número de frutos não comerciáveis (fundo preto.Plant cultivation in substrate under greenhouse conditions needs technical knowledge to promote water and nutrient use efficiency. In this work were evaluated the tomato development and yield under different irrigation frequencies cultivated in greenhouse. The experiment was carried out in Campinas, São Paulo State, Brazil, from November, 2003 to April, 2004. The experimental design consisted of six treatments in randomized blocks with four replications. The treatments consisted of the irrigation frequencies: five, four, three, two and one times a day and irrigation on alternating days. The irrigation was applied by drip irrigation system. The substrate consisted of coconut fiber. The one, three, four and five times a day irrigation frequency provided better total marketable tomato yield

  1. 2D Spatial Frequency Considerations in Comparing 1D Power Spectral Density Measurements

    International Nuclear Information System (INIS)

    Takacs, P.Z.; Barber, S.; Church, E.L.; Kaznatcheev, K.; McKinney, W.R.; Yashchuk, V.Y.

    2010-01-01

    The frequency footprint of ID and 2D profiling instruments needs to be carefully considered in comparing ID surface roughness spectrum measurements made by different instruments. Contributions from orthogonal direction frequency components can not be neglected. The use of optical profiling instruments is ubiquitous in the measurement of the roughness of optical surfaces. Their ease-of-use and non-contact measurement method found widespread use in the optics industry for measuring the quality of delicate optical surfaces. Computerized digital data acquisition with these instruments allowed for quick and easy calculation of surface roughness statistics, such as root-mean-square (RMS) roughness. The computing power of the desktop computer allowed for the rapid conversion of spatial domain data into the frequency domain, enabling the application of sophisticated signal processing techniques to be applied to the analysis of surface roughness, the most powerful of which is the power spectral density (PSP) function. Application of the PSD function to surface statistics introduced the concept of 'bandwidth-limited' roughness, where the value of the RMS roughness depends critically upon the spatial frequency response of the instrument. Different instruments with different spatial frequency response characteristics give different answers when measuring the same surface.

  2. Effects of different irrigation methods and plant densities on silage quality parameters of PR 31Y43 hybrid corn cultivar (Zea mays L. var. indentata [Sturtev.] L.H. Bailey

    Directory of Open Access Journals (Sweden)

    Muhammet Karasahin

    2014-03-01

    Full Text Available The yield and quality of corn silage is related to genotype as well as factors such as climate, soil conditions, altitude, planting time, plant density, irrigation, and harvesting time. This study was conducted to determine the effects of different irrigation methods (drip, subsoil drip, and subsoil capillary and different plant densities (102 040, 119 040, and 142 850 plant ha-1 on silage quality parameters of PR 31Y43 hybrid corn (Zea mays L. var. indentata [Sturtev.] L.H. Bailey in 2011 and 2012 under ecological conditions in Eskipazar-Karabuk, Turkey. Plant densities were significantly different on fresh ear ratio and plant crude protein (CP yield in both years under study. The highest fresh ear ratio values were obtained with 102 040 and 119 040 plant ha-1 densities and the highest plant CP yield with 142 850 plant ha-1. While the irrigation method x plant density interactions were significant for silage CP ratio in the first year, they were significant on fresh ear ratio in the second year. The highest fresh ear ratio values were obtained from subsoil capillary x 119 040 plant ha-1 and drip x 119 040 plant ha-1 interactions; the highest plant and silage CP ratio values were obtained from subsoil capillary x 142 850 plant ha-1 and subsoil drip x 102 040 plant ha-1 interactions. As a result of the research, high Flieg scores were obtained from each irrigation method and plant density. When plant CP yield is taken into consideration, the 142 850 plant ha-1 density is more important.

  3. Solar wind electron densities from Viking dual-frequency radio measurements

    International Nuclear Information System (INIS)

    Muhleman, D.O.; Anderson, J.D.

    1981-01-01

    Simultaneous phase coherent, two-frequency measurements of the time delay between the Earth station and the Viking spacecraft have been analyzed in terms of the electron density profiles from 4 solar radii (R/sub sun/) to 200 R/sub sun/. The measurements were made during a period of solar activity minimum (1976--1977) and show a strong solar latitude effect. The data were analyzed with both a model independent, direct numerical inversion technique and with model fitting, yielding essentially the same results. It is shown that the solar wind density can be represented by two power laws near the solar equator proportional to r/sup -2.7/ and r/sup -2.04/. However, the more rapidly falling term quickly disappears at moderate latitudes (approx.20 0 ), leaving only the inverse-square behavior

  4. Microwave frequency sweep interferometer for plasma density measurements in ECR ion sources: Design and preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Torrisi, Giuseppe [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); University Mediterranea of Reggio Calabria, Reggio Calabria (Italy); Mascali, David; Neri, Lorenzo; Leonardi, Ornella; Celona, Luigi; Castro, Giuseppe; Agnello, Riccardo; Caruso, Antonio; Passarello, Santi; Longhitano, Alberto; Gammino, Santo [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Sorbello, Gino [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); University of Catania, Catania, Italy and INFN-LNS, Catania (Italy); Isernia, Tommaso [University Mediterranea of Reggio Calabria, Reggio Calabria (Italy)

    2016-02-15

    The Electron Cyclotron Resonance Ion Sources (ECRISs) development is strictly related to the availability of new diagnostic tools, as the existing ones are not adequate to such compact machines and to their plasma characteristics. Microwave interferometry is a non-invasive method for plasma diagnostics and represents the best candidate for plasma density measurement in hostile environment. Interferometry in ECRISs is a challenging task mainly due to their compact size. The typical density of ECR plasmas is in the range 10{sup 11}–10{sup 13} cm{sup −3} and it needs a probing beam wavelength of the order of few centimetres, comparable to the chamber radius. The paper describes the design of a microwave interferometer developed at the LNS-INFN laboratories based on the so-called “frequency sweep” method to filter out the multipath contribution in the detected signals. The measurement technique and the preliminary results (calibration) obtained during the experimental tests will be presented.

  5. Direct measurement of density oscillation induced by a radio-frequency wave

    International Nuclear Information System (INIS)

    Yamada, T.; Ejiri, A.; Shimada, Y.; Oosako, T.; Tsujimura, J.; Takase, Y.; Kasahara, H.

    2007-01-01

    An O-mode reflectometer at a frequency of 25.85 GHz was applied to plasmas heated by the high harmonic fast wave (21 MHz) in the TST-2 spherical tokamak. An oscillation in the phase of the reflected microwave in the rf range was observed directly for the first time. In TST-2, the rf (250 kW) induced density oscillation depends mainly on the poloidal rf electric field, which is estimated to be about 0.2 kV/m rms by the reflectometer measurement. Sideband peaks separated in frequency by ion cyclotron harmonics from 21 MHz, and peaks at ion cyclotron harmonics which are suggested to be quasimodes generated by parametric decay, were detected

  6. 1 μs broadband frequency sweeping reflectometry for plasma density and fluctuation profile measurements

    Science.gov (United States)

    Clairet, F.; Bottereau, C.; Medvedeva, A.; Molina, D.; Conway, G. D.; Silva, A.; Stroth, U.; ASDEX Upgrade Team; Tore Supra Team; Eurofusion Mst1 Team

    2017-11-01

    Frequency swept reflectometry has reached the symbolic value of 1 μs sweeping time; this performance has been made possible, thanks to an improved control of the ramp voltage driving the frequency source. In parallel, the memory depth of the acquisition system has been upgraded and can provide up to 200 000 signals during a plasma discharge. Additional improvements regarding the trigger delay determination of the acquisition and the voltage ramp linearity required by this ultra-fast technique have been set. While this diagnostic is traditionally dedicated to the plasma electron density profile measurement, such a fast sweeping rate can provide the study of fast plasma events and turbulence with unprecedented time and radial resolution from the edge to the core. Experimental results obtained on ASDEX Upgrade plasmas are presented to demonstrate the performances of the diagnostic.

  7. A simple microwave technique for plasma density measurement using frequency modulation

    International Nuclear Information System (INIS)

    Bora, D.; Jayakumar, R.; Vijayashankar, M.K.

    1984-01-01

    A simple method of determining the phase variation unambiguously during microwave interferometric measurement is described. The frequency of the Klystron source is modulated with the help of staircase voltage pulse. The height of each stair is adjusted such that the corresponding phase shift in the test branch with an additional path length is 90 0 . Signals, proportional to cosine and sine of the phase shift due to plasma, can be generated in the same channel and plasma density information can be inferred. The microwave hardware remains the same as in conventional interferometry and the cost of such a scheme is low. (author)

  8. Assessment of plasma impedance probe for measuring electron density and collision frequency in a plasma with spatial and temporal gradients

    International Nuclear Information System (INIS)

    Hopkins, Mark A.; King, Lyon B.

    2014-01-01

    Numerical simulations and experimental measurements were combined to determine the ability of a plasma impedance probe (PIP) to measure plasma density and electron collision frequency in a plasma containing spatial gradients as well as time-varying oscillations in the plasma density. A PIP is sensitive to collision frequency through the width of the parallel resonance in the Re[Z]-vs.-frequency characteristic, while also being sensitive to electron density through the zero-crossing of the Im[Z]-vs.-frequency characteristic at parallel resonance. Simulations of the probe characteristic in a linear plasma gradient indicated that the broadening of Re[Z] due to the spatial gradient obscured the broadening due to electron collision frequency, preventing a quantitative measurement of the absolute collision frequency for gradients considered in this study. Simulation results also showed that the PIP is sensitive to relative changes in electron collision frequency in a spatial density gradient, but a second broadening effect due to time-varying oscillations made collision frequency measurements impossible. The time-varying oscillations had the effect of causing multiple zero-crossings in Im[Z] at parallel resonance. Results of experiments and simulations indicated that the lowest-frequency zero-crossing represented the lowest plasma density in the oscillations and the highest-frequency zero-crossing represented the highest plasma density in the oscillations, thus the PIP probe was found to be an effective tool to measure both the average plasma density as well as the maximum and minimum densities due to temporal oscillations

  9. Collision frequency of Lennard-Jones fluids at high densities by equilibrium molecular dynamics simulation

    International Nuclear Information System (INIS)

    Adebayo, G.A.; Anusionwu, B.C.; Njah, A.N.; Adeniran, O.J.; Mathew, B.; Sunmonu, R.S.

    2009-01-01

    Arising from the inability of theoretical calculations to give accurate descriptions of (shear) viscosity in rare gases at high densities, we investigated the likely cause of discrepancy between theory and experiments. Molecular Dynamics simulations were performed to calculate transport coefficients and collision frequency of rare gases at high densities and different temperatures using a Lennard-Jones modelled pair potential. The results, when compared with experiments show an underestimation of the viscosity calculated through the Green-Kubo formalism, but in agreement with some other calculations performed by other groups. In the present work the origin of the underestimation is considered. Analyses of the transport coefficients show a very high collision frequency which suggests an atom may spend much less time in the neighbourhood of the fields of force of another atom and that the distribution in the systems studied adjusts itself to a nearly Maxwellian type which resulted in a locally and temporarily slowly varying temperature. We show that the time spent in the fields of force is so small compared with relaxation time thereby leading to a possible reduction in local velocity auto-correlation between atoms. (author)

  10. Effect of pulse frequency and current density on anomalous composition and nanomechanical property of electrodeposited Ni-Co films

    Energy Technology Data Exchange (ETDEWEB)

    Chung, C.K., E-mail: ckchung@mail.ncku.edu.t [Department of Mechanical Engineering, and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan, Taiwan 701 (China); Chang, W.T. [Department of Mechanical Engineering, and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan, Taiwan 701 (China)

    2009-07-01

    Effect of pulse frequency and current density on the anomalous cobalt content and nanomechanical property of the electrodeposited nickel-cobalt (Ni-Co) films has been investigated. The composition, morphology, phase and hardness of the Ni-Co alloy films were examined by scanning electron microscope with an attached energy dispersive X-ray spectroscope, X-ray diffraction and nanoindentation techniques, respectively. The different Co composition of the Ni-Co films codeposited from the fixed sulfamate-chloride bath is subject to the pulse frequencies and current densities. The frequencies varied from 0 to 100 Hz and current densities varied from 1 to 20 ASD (ampere per square decimeter). The Co composition has no significant variation in pulse electrodeposition but it is greatly influenced by current densities from 22.53% at 1 ASD decreased to 13.39% at 20 ASD under DC codeposition. The mean hardness of Ni-Co films has no eminent change at a pulse frequency of 10-100 Hz but it decreases with current densities from 8.72 GPa (1 ASD) to 7.13 GPa (20 ASD). The smoother morphology can be obtained at higher pulse frequency or lower current density. Good Ni-Co films with high hardness and smooth morphology can be obtained by reducing current density and increasing pulse frequency.

  11. Electron Density Profile Data Contains Virtual Height/Frequency Pairs from a Profile or Profiles (Composite Months) of Ionograms

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Electron Density Profile, N(h), data set contains both individual profiles and composite months. The data consist of virtual height/frequency pairs from a...

  12. Densidade do sistema radicular da bananeira 'Pacovan' sob irrigação por aspersão Root system density of 'Pacovan' banana plant under sprinkler irrigation

    Directory of Open Access Journals (Sweden)

    Raimundo Lacerda Filho

    2004-12-01

    Full Text Available O presente trabalho foi realizado no município de Governador Dix-Sept Rosado, microrregião Açu-Apodi, no Estado do Rio Grande do Norte, tendo como objetivo verificar os efeitos do sistema de irrigação por aspersão na densidade do sistema radicular da bananeira 'Pacovan'. O delineamento experimental utilizado foi o de blocos casualizados, em esquema de parcelas subdivididas, com cinco repetições. Os tratamentos foram duas amostragens por planta, realizadas do lado contrário ao da emissão da inflorescência, formando um ângulo de 45º. Em cada amostragem, foram realizadas quatro retiradas do material de solo a distâncias de 20 cm, sendo a primeira a 30 cm e a última a 90 cm do pseudocaule. A análise dos dados demonstrou que ocorreu redução linear no peso fresco e na densidade de comprimento de raízes da bananeira em função da profundidade do solo. Em relação à distância do pseudocaule da bananeira, tanto o peso fresco quanto a densidade de comprimento de raízes não mostraram resultados significativos.The present work was conducted at Governador Dix-Sept Rosado County, microregion Açu-Apodi, in the state of Rio Grande do Norte and its objective was to study the effects of sprinkler irrigation system on the density of the root system of 'Pacovan' banana plants. The experiment followed a completely randomized block design, in a split-plot scheme, with five replications. The treatments were two sampling groups, taken per plant, and in the opposite side of the inflorescence emission, forming between them an angle of 45°. In each sampling group, four samples containing soil material were collected at intervals of 20 cm, so the first was distant 30 cm and the last 90 cm from the pseudostem. Data analysis showed that occurred a linear reduction in root fresh weight and in lenght of roots density, in replications to soil depth. For the distance from the plant pseudostem there were no significant differences between samples, both

  13. Density functional theory for prediction of far-infrared vibrational frequencies: molecular crystals of astrophysical interest

    Science.gov (United States)

    Ennis, C.; Auchettl, R.; Appadoo, D. R. T.; Robertson, E. G.

    2017-11-01

    Solid-state density functional theory code has been implemented for the structure optimization of crystalline methanol, acetaldehyde and acetic acid and for the calculation of infrared frequencies. The results are compared to thin film spectra obtained from low-temperature experiments performed at the Australian Synchrotron. Harmonic frequency calculations of the internal modes calculated at the B3LYP-D3/m-6-311G(d) level shows higher deviation from infrared experiment than more advanced theory applied to the gas phase. Importantly for the solid-state, the simulation of low-frequency molecular lattice modes closely resembles the observed far-infrared features after application of a 0.92 scaling factor. This allowed experimental peaks to be assigned to specific translation and libration modes, including acetaldehyde and acetic acid lattice features for the first time. These frequency calculations have been performed without the need for supercomputing resources that are required for large molecular clusters using comparable levels of theory. This new theoretical approach will find use for the rapid characterization of intermolecular interactions and bonding in crystals, and the assignment of far-infrared spectra for crystalline samples such as pharmaceuticals and molecular ices. One interesting application may be for the detection of species of prebiotic interest on the surfaces of Kuiper-Belt and Trans-Neptunian Objects. At such locations, the three small organic molecules studied here could reside in their crystalline phase. The far-infrared spectra for their low-temperature solid phases are collected under planetary conditions, allowing us to compile and assign their most intense spectral features to assist future far-infrared surveys of icy Solar system surfaces.

  14. Quasiparticle density of states in a half metal in the presence of odd-frequency Cooper pairs

    NARCIS (Netherlands)

    Asano, Yasuhiro; Yokoyama, Takehito; Tanaka, Yukio; Golubov, Alexandre Avraamovitch

    2008-01-01

    We study the local density of states in a half metal sandwiched by the two superconductors. The spin-flip scattering at the junction interface opens the Josephson channels of the odd-frequency spin-triplet s-wave Cooper pairs. The penetration of the odd-frequency pairs enhances the quasiparticle

  15. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y., E-mail: thuzhangyu@foxmail.com; Huang, S. L., E-mail: huangsling@tsinghua.edu.cn; Wang, S.; Zhao, W. [State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084 (China)

    2016-05-15

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert–Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of <1% and thus can act as a universal time-of-flight extraction method for narrowband Lamb wave detection signals.

  16. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals

    International Nuclear Information System (INIS)

    Zhang, Y.; Huang, S. L.; Wang, S.; Zhao, W.

    2016-01-01

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert–Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of <1% and thus can act as a universal time-of-flight extraction method for narrowband Lamb wave detection signals.

  17. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals.

    Science.gov (United States)

    Zhang, Y; Huang, S L; Wang, S; Zhao, W

    2016-05-01

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert-Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of wave detection signals.

  18. Equilibrium finite-frequency noise of an interacting mesoscopic capacitor studied in time-dependent density functional theory

    Science.gov (United States)

    Dittmann, Niklas; Splettstoesser, Janine; Helbig, Nicole

    2018-03-01

    We calculate the frequency-dependent equilibrium noise of a mesoscopic capacitor in time-dependent density functional theory (TDDFT). The capacitor is modeled as a single-level quantum dot with on-site Coulomb interaction and tunnel coupling to a nearby reservoir. The noise spectra are derived from linear-response conductances via the fluctuation-dissipation theorem. Thereby, we analyze the performance of a recently derived exchange-correlation potential with time-nonlocal density dependence in the finite-frequency linear-response regime. We compare our TDDFT noise spectra with real-time perturbation theory and find excellent agreement for noise frequencies below the reservoir temperature.

  19. Irrigation Requirement Estimation using MODIS Vegetation Indices and Inverse Biophysical Modeling; A Case Study for Oran, Algeria

    Science.gov (United States)

    Bounoua, L.; Imhoff, M.L.; Franks, S.

    2008-01-01

    Human demand for food influences the water cycle through diversion and extraction of fresh water needed to support agriculture. Future population growth and economic development alone will substantially increase water demand and much of it for agricultural uses. For many semi-arid lands, socio-economic shifts are likely to exacerbate changes in climate as a driver of future water supply and demand. For these areas in particular, where the balance between water supply and demand is fragile, variations in regional climate can have potentially predictable effect on agricultural production. Satellite data and biophysically-based models provide a powerful method to quantify the interactions between local climate, plant growth and water resource requirements. In irrigated agricultural lands, satellite observations indicate high vegetation density while the precipitation amount indicates otherwise. This inconsistency between the observed precipitation and the observed canopy leaf density triggers the possibility that the observed high leaf density is due to an alternate source of water, irrigation. We explore an inverse process approach using observations from the Moderate Resolution Imaging Spectroradiometer (MODIS), climatological data, and the NASA's Simple Biosphere model, SiB2, to quantitatively assess water demand in a semi-arid agricultural land by constraining the carbon and water cycles modeled under both equilibrium (balance between vegetation and prevailing local climate) and nonequilibrium (water added through irrigation) conditions. We postulate that the degree to which irrigated lands vary from equilibrium conditions is related to the amount of irrigation water used. We added water using two distribution methods: The first method adds water on top of the canopy and is a proxy for the traditional spray irrigation. The second method allows water to be applied directly into the soil layer and serves as proxy for drip irrigation. Our approach indicates that over

  20. First density profile measurements using frequency modulation of the continuous wave reflectometry on JETa)

    Science.gov (United States)

    Meneses, L.; Cupido, L.; Sirinelli, A.; Manso, M. E.; Jet-Efds Contributors

    2008-10-01

    We present the main design options and implementation of an X-mode reflectometer developed and successfully installed at JET using an innovative approach. It aims to prove the viability of measuring density profiles with high spatial and temporal resolution using broadband reflectometry operating in long and complex transmission lines. It probes the plasma with magnetic fields between 2.4 and 3.0 T using the V band [~(0-1.4)×1019 m-3]. The first experimental results show the high sensitivity of the diagnostic when measuring changes in the plasma density profile occurring ITER relevant regimes, such as ELMy H-modes. The successful demonstration of this concept motivated the upgrade of the JET frequency modulation of the continuous wave (FMCW) reflectometry diagnostic, to probe both the edge and core. This new system is essential to prove the viability of using the FMCW reflectometry technique to probe the plasma in next step devices, such as ITER, since they share the same waveguide complexity.

  1. Theory of sum-frequency generation spectroscopy of adsorbed molecules using the density matrix method-broadband vibrational sum-frequency generation and applications

    International Nuclear Information System (INIS)

    Bonn, M; Ueba, H; Wolf, M

    2005-01-01

    A generalized theory of frequency- and time-resolved vibrational sum-frequency generation (SFG) spectroscopy of adsorbates at surfaces is presented using the density matrix formalism. Our theoretical treatment is specifically aimed at addressing issues that accompany the relatively novel SFG approach using broadband infrared pulses. The ultrashort duration of these pulses makes them ideally suited for time-resolved investigations, for which we present a complete theoretical treatment. A second key characteristic of these pulses is their large bandwidth and high intensity, which allow for highly non-linear effects, including vibrational ladder climbing of surface vibrations. We derive general expressions relating the density matrix to SFG spectra, and apply these expressions to specific experimental results by solving the coupled optical Bloch equations of the density matrix elements. Thus, we can theoretically reproduce recent experimentally demonstrated hot band SFG spectra using femtosecond broadband infrared excitation of carbon monoxide (CO) on a Ru(001) surface

  2. Role of the Coulomb interaction in the low-frequency density of states of DNA double helices

    International Nuclear Information System (INIS)

    Garcia, A.E.; Krumhansl, J.A.

    1988-01-01

    The complete vibrational frequency spectrum of several DNA double-helical oligomers is calculated using established pair potentials. Various cutoff values are used for the range of the Coulomb interactions. At very low frequency the integrated density of states shows a noninteger exponent with values ranging from 0.75 to 1.55, depending on the cutoff value for the Coulomb interactions. We conclude that the cumulative densities of states in those molecules depend more on competing interactions than on various proposed universal laws

  3. Correlation between radiographic analysis of alveolar bone density around dental implant and resonance frequency of dental implant

    Science.gov (United States)

    Prawoko, S. S.; Nelwan, L. C.; Odang, R. W.; Kusdhany, L. S.

    2017-08-01

    The histomorphometric test is the gold standard for dental implant stability quantification; however, it is invasive, and therefore, it is inapplicable to clinical patients. Consequently, accurate and objective alternative methods are required. Resonance frequency analysis (RFA) and digital radiographic analysis are noninvasive methods with excellent objectivity and reproducibility. To analyze the correlation between the radiographic analysis of alveolar bone density around a dental implant and the resonance frequency of the dental implant. Digital radiographic images for 35 samples were obtained, and the resonance frequency of the dental implant was acquired using Osstell ISQ immediately after dental implant placement and on third-month follow-up. The alveolar bone density around the dental implant was subsequently analyzed using SIDEXIS-XG software. No significant correlation was reported between the alveolar bone density around the dental implant and the resonance frequency of the dental implant (r = -0.102 at baseline, r = 0.146 at follow-up, p > 0.05). However, the alveolar bone density and resonance frequency showed a significant difference throughout the healing period (p = 0.005 and p = 0.000, respectively). Conclusion: Digital dental radiographs and Osstell ISQ showed excellent objectivity and reproducibility in quantifying dental implant stability. Nonetheless, no significant correlation was observed between the results obtained using these two methods.

  4. Assessment of the effect of three-dimensional mantle density heterogeneity on earth rotation in tidal frequencies.

    Science.gov (United States)

    Liu, Lanbo; Chao, Benjamin F; Sun, Wenke; Kuang, Weijia

    2016-11-01

    In this paper we report the assessment of the effect of the three-dimensional (3D) density heterogeneity in the mantle on Earth Orientation Parameters (EOP) (i.e., the polar motion, or PM, and the length of day, or LOD) in the tidal frequencies. The 3D mantle density model is estimated based upon a global S-wave velocity tomography model (S16U6L8) and the mineralogical knowledge derived from laboratory experiment. The lateral density variation is referenced against the Preliminary Reference Earth Model (PREM). Using this approach the effects of the heterogeneous mantle density variation in all three tidal frequencies (zonal long periods, tesseral diurnal, and sectorial semidiurnal) are estimated in both PM and LOD. When compared with mass or density perturbations originated on the earth's surface such as the oceanic and barometric changes, the heterogeneous mantle only contributes less than 10% of the total variation in PM and LOD in tidal frequencies. Nevertheless, including the 3D variation of the density in the mantle into account explained a substantial portion of the discrepancy between the observed signals in PM and LOD extracted from the lump-sum values based on continuous space geodetic measurement campaigns (e.g., CONT94) and the computed contribution from ocean tides as predicted by tide models derived from satellite altimetry observations (e.g., TOPEX/Poseidon). In other word, the difference of the two, at all tidal frequencies (long-periods, diurnals, and semi-diurnals) contains contributions of the lateral density heterogeneity of the mantle. Study of the effect of mantle density heterogeneity effect on torque-free earth rotation may provide useful constraints to construct the Reference Earth Model (REM), which is the next major objective in global geophysics research beyond PREM.

  5. High-frequency emissions during the propagation of an electron beam in a high-density plasma

    International Nuclear Information System (INIS)

    Lalita and Tripathi, V.K.

    1988-01-01

    A relativistic annular electron beam passing through a high-density plasma excites Langmuir waves via Cerenkov interaction. The Langmuir waves are backscattered off ions via nonlinear ion Landau damping. At moderately high amplitudes these waves are parametrically up-converted by the beam into high-frequency electromagnetic radiation, as observed in some recent experiments. A nonlocal theory of this process is developed in a cylindrical geometry. It is seen that the growth rate of the Langmuir wave scales as one-third power of beam density. The growth rate of parametric instability scales as one-fourth power of beam density and the square root of beam thickness

  6. Molecular Structure And Vibrational Frequencies of Tetrafluoro isophthalonitrile By Hartree-Fock And Density Functional Theory Calculations

    International Nuclear Information System (INIS)

    Ayikoglu, A.

    2008-01-01

    The molecular structure, vibrational frequencies and corresponding vibrational assignments of tetrafluoro isophthalonitrile (TFPN) in the ground state have been calculated using the Hartree-Fock (HF) and density functional methods (B3LYP) with 6-311++G (d, p) basis set. The calculations were utilized in the CS symmetry of TFPN. The obtained vibrational frequencies and optimized geometric parameters (bond lengths and bond angles) were seen to be in good agreement with the experimental data. The comparison of the observed and calculated results showed that the B3LYP method is superior to the HF method for both the vibrational frequencies and geometric parameters

  7. Adult trees cause density-dependent mortality in conspecific seedlings by regulating the frequency of pathogenic soil fungi.

    Science.gov (United States)

    Liang, Minxia; Liu, Xubing; Gilbert, Gregory S; Zheng, Yi; Luo, Shan; Huang, Fengmin; Yu, Shixiao

    2016-12-01

    Negative density-dependent seedling mortality has been widely detected in tropical, subtropical and temperate forests, with soil pathogens as a major driver. Here we investigated how host density affects the composition of soil pathogen communities and consequently influences the strength of plant-soil feedbacks. In field censuses of six 1-ha permanent plots, we found that survival was much lower for newly germinated seedlings that were surrounded by more conspecific adults. The relative abundance of pathogenic fungi in soil increased with increasing conspecific tree density for five of nine tree species; more soil pathogens accumulated around roots where adult tree density was higher, and this greater pathogen frequency was associated with lower seedling survival. Our findings show how tree density influences populations of soil pathogens, which creates plant-soil feedbacks that contribute to community-level and population-level compensatory trends in seedling survival. © 2016 John Wiley & Sons Ltd/CNRS.

  8. Study of the ion density of a radio-frequency plasma using electrostatic probes and focussed microwave interferometers

    International Nuclear Information System (INIS)

    Nguyen Cao, L.; Gagne, R.R.J.

    1976-01-01

    In order to verify experimentally and compare recent ion theories for cylindrical electrostatic probes, the ion density in a radio-frequency plasma was evaluated from V-I curves by means of six different theories. At low pressures, the theories of Bernstein and Rabinowitz, of Lam and Laframboise, give values of density which differ respectively by 20, 25 and 30% compared with the values obtained using a 10GHz focussed microwave interferometer. At the continuum limit, The Schulz and Brown's, and Su and Kiel's theories give density values which disagree respectively by 55 and 20%, compared with the values obtained by microwaves. For pressures varying from 0.05 to 3mmHg, the decrease of ion current, as predicted theorically by Waymouth, was observed. The density perturbation near the probe was found to be a dominant factor affecting the precision of density measurements, for pressures up to 2mmHg at least for our experimental conditions [fr

  9. Unified analytical expressions for calculating resonant frequencies, transimpedances, and equivalent input noise current densities of tuned receiver front ends

    DEFF Research Database (Denmark)

    Liu, Qing Zhong

    1992-01-01

    Unified analytical expressions have been derived for calculating the resonant frequencies, transimpedance and equivalent input noise current densities of the four most widely used tuned optical receiver front ends built with FETs and p-i-n diodes. A more accurate FET model has been used to improve...

  10. The density of states for almost periodic Schroedinger operators and the frequency module: a counter-example

    International Nuclear Information System (INIS)

    Bellissard, J.

    1981-07-01

    We exhibit an example of a one-dimensional discrete Schroedinger operator with an almost periodic potential for which the steps of the density of states do not belong to the frequency module. This example is suggested by the K-theory

  11. Critical frequency and maximum electron density of F2 region over four stations in the North American sector

    Czech Academy of Sciences Publication Activity Database

    Ezquer, R. G.; Cabrera, M. A.; López, J. L.; Albornoz, M. R.; Mosert, M.; Marcó, P.; Burešová, Dalia

    2011-01-01

    Roč. 73, č. 4 (2011), s. 420-429 ISSN 1364-6826 Institutional research plan: CEZ:AV0Z30420517 Keywords : Ionosphere * F2 region * Critical frequency * Electron density * Model Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.596, year: 2011 http://www.sciencedirect.com/science/article/pii/S1364682610002786

  12. Word Recognition and Nonword Repetition in Children with Language Disorders: The Effects of Neighborhood Density, Lexical Frequency, and Phonotactic Probability

    Science.gov (United States)

    Rispens, Judith; Baker, Anne; Duinmeijer, Iris

    2015-01-01

    Purpose: The effects of neighborhood density (ND) and lexical frequency on word recognition and the effects of phonotactic probability (PP) on nonword repetition (NWR) were examined to gain insight into processing at the lexical and sublexical levels in typically developing (TD) children and children with developmental language problems. Method:…

  13. Power spectral density and scaling exponent of high frequency global solar radiation sequences

    Science.gov (United States)

    Calif, Rudy; Schmitt, François G.; Huang, Yongxiang

    2013-04-01

    invariance: Iq(f) ~ f-?(q) , ?(q) is the scaling exponent. This allows to characterize the scaling behavior of a process: fractal or multifractal with intermittent properties. For q = 2, the Hilbert spectrum is defined. In this work, The data are collected at the University site of Guadeloupe, an island in the West Indies, located at 16°15 N latitude 60°30 W longitude. Our measurements sampled at 1 Hz were performed during one year period. The analyzed data present a power spectral density E(f) displaying a power law of the form E(f) ~ f-β with 1.6 ˜ β ˜ 2.2 for frequencies f ˜ 0.1 Hz, corresponding to time scales T × 10 s. Furthermore, global solar radiation data possesses multifractal properties. For comparison, other multifractal analysis techniques such as structure functions, MDFA, wavelet leaders are also used. This preliminary work set the basis for further investigation dedicated to simulate and forecast a sequence of solar energy fluctuation under different meteorological conditions, in the multifractal framework.

  14. Design of an O-mode frequency modulated reflectometry system for the measurement of Alborz Tokamak plasma density profile

    Energy Technology Data Exchange (ETDEWEB)

    Koohestani, Saeideh [Department of Energy Engineering and physics, Amirkabir University of Technology, Tehran, 15875-4413, Islamic Republic of Iran (Iran, Islamic Republic of); Amrollahi, Reza, E-mail: amrollahi@aut.ac.ir [Department of Energy Engineering and physics, Amirkabir University of Technology, Tehran, 15875-4413, Islamic Republic of Iran (Iran, Islamic Republic of); Moradi, Gholamreza [Department of Electrical Engineering, Amirkabir University of Technology, Tehran, 15875-4413, Islamic Republic of Iran (Iran, Islamic Republic of)

    2016-12-15

    Reflectometry is a common method for plasma diagnostic, in which microwaves are launched into the plasma and reflected at the critical surfaces. Comparing the reflected microwave signals with the launched waves would give rise to the plasma density profiles. In the present study, an ordinary mode (O-mode) frequency modulation (FM) reflectometry system has been designed for the electron density profile measurement of the Alborz Tokamak plasma. This system has been considered to operate at K-band (18–26.5 GHz) frequency range and scan the frequency band between 18 to 26 GHz in 40 μS. The density profile from major radius r = 47.9–51.55 cm can be measured in Alborz Tokamak plasma. Based on the Alborz Tokamak operational conditions, the characteristic frequencies, and some dimensional limitations, all parts of reflectometer have been designed so that an appropriate efficiency with minimum attenuation, especially in transmitting/receiving system would be achieved. A dual antenna and an oversized waveguide of X-band (8–12 GHz) for transmitting and receiving purposes and a balanced detector for absolute phase determination have been utilized. The details of the Alborz Tokamak FM reflectometry components focusing on the antenna and waveguide design and mounting are described in this paper. Additionally, the procedure of plasma profile reconstruction using the system output signal is discussed. This system uses signal phase shift to determine the position of the cutoff layer.

  15. Irrigation Requirement Estimation Using Vegetation Indices and Inverse Biophysical Modeling

    Science.gov (United States)

    Bounoua, Lahouari; Imhoff, Marc L.; Franks, Shannon

    2010-01-01

    We explore an inverse biophysical modeling process forced by satellite and climatological data to quantify irrigation requirements in semi-arid agricultural areas. We constrain the carbon and water cycles modeled under both equilibrium, balance between vegetation and climate, and non-equilibrium, water added through irrigation. We postulate that the degree to which irrigated dry lands vary from equilibrium climate conditions is related to the amount of irrigation. The amount of water required over and above precipitation is considered as an irrigation requirement. For July, results show that spray irrigation resulted in an additional amount of water of 1.3 mm per occurrence with a frequency of 24.6 hours. In contrast, the drip irrigation required only 0.6 mm every 45.6 hours or 46% of that simulated by the spray irrigation. The modeled estimates account for 87% of the total reported irrigation water use, when soil salinity is not important and 66% in saline lands.

  16. Optimized Irregular Low-Density Parity-Check Codes for Multicarrier Modulations over Frequency-Selective Channels

    Directory of Open Access Journals (Sweden)

    Valérian Mannoni

    2004-09-01

    Full Text Available This paper deals with optimized channel coding for OFDM transmissions (COFDM over frequency-selective channels using irregular low-density parity-check (LDPC codes. Firstly, we introduce a new characterization of the LDPC code irregularity called “irregularity profile.” Then, using this parameterization, we derive a new criterion based on the minimization of the transmission bit error probability to design an irregular LDPC code suited to the frequency selectivity of the channel. The optimization of this criterion is done using the Gaussian approximation technique. Simulations illustrate the good performance of our approach for different transmission channels.

  17. Eficiência do uso da água pelo meloeiro sob diferentes freqüências de irrigação Water use efficiency of the melon crop under different irrigation frequencies

    Directory of Open Access Journals (Sweden)

    Valdemício Ferreira de Sousa

    2000-01-01

    Full Text Available Objetivou-se, com este estudo, avaliar o efeito de cinco freqüências de irrigação por gotejamento, na maximização da produtividade e na eficiência do uso da água pelo meloeiro cultivado em solo arenoso de Tabuleiro Costeiro do Piauí. O experimento foi conduzido no Campo Experimental da Embrapa Meio-Norte, localizado no município de Parnaíba, PI, latitude 3º5'S longitude 41º47'W e altitude de 46,8 m. O delineamento experimental foi o de blocos ao acaso, com cinco tratamentos e seis repetições, em que os tratamentos foram: freqüências de irrigação de 0,50, 1,0, 2,0, 3,0 e 4,0 dias. Foram avaliadas as produtividades comercial e total e a eficiência do uso de água, constatando-se que a maior produtividade total (77.985 kg ha-1 e a máxima eficiência do uso da água (EUAEt pelo meloeiro (282,83 kg ha-1 mm-1 são obtidas com freqüência de irrigação de um dia. As freqüências de irrigação de 3 e 4 dias, ou superiores, não são recomendadas para o meloeiro e, se a água é escassa, utilizam-se irrigações com freqüência diária.The objective of this work was to evaluate the effect of five trickle irrigation frequencies to obtain high yields and maximum water use efficiency in a melon crop cultivated in sandy soil of the Coastal Tablelands of Piauí, Brazil. The experiment was carried out in an experimental area of Embrapa Meio-Norte in Parnaíba, Piauí State, Brazil, latitude 3º5' S, longitude 41º47' W and altitude 46.8 m. A randomized block with five treatments and six replications was used, with irrigation frequencies of 0.5, 1.0, 2.0, 3.0 and 4.0 days. The total and commercial yield and water use efficiency were evaluated. The highest total yield (77.985 kg ha-1 and the maximum water use efficiency by melon crop (282.83 kg ha-1 mm-1 were obtained with an irrigation frequency of one day. The irrigation frequencies of 3 and 4 days or higher are not recommended for the melon crop, and if the water is scarce an

  18. Utilização do inversos de freqüência em sistemas de irrigação para controle de vazão Utilization of a variable frequency drive in irrigation systems to control discharge

    Directory of Open Access Journals (Sweden)

    Jacinto de Assunção Carvalho

    2000-04-01

    Full Text Available Objetivou-se, com este trabalho, avaliar o uso de um inversor de freqüência de 25 cv na irrigação, considerando-se diferentes demandas de água como manejo. A avaliação consistiu de uma análise de custos e benefícios, ambos anuais. O custo foi calculado com base no fator de recuperação do capital, para taxas de juros de 6 e 12% e períodos de amortização de 5 e 15 anos. O benefício consistiu da economia de energia proporcionada pelo inversor de freqüência em relação aos procedimentos usuais de controle da vazão. Relacionaram-se os parâmetros econômicos e de manejo da irrigação, com o objetivo de se avaliar o equipamento para qualquer situação de projeto. Como exemplo de aplicação, analisaram-se duas situações de controle de vazão comparadas ao inversor de freqüência em um projeto de irrigação. Foram determinadas, com auxílio do inversor de freqüência, as características hidráulicas, em função da vazão de uma motobomba de 25 cv sob várias rotações. Observou-se que o inversor de freqüência pode ser viável, devendo-se avaliar a redução de potência advinda do seu uso e o tempo de funcionamento da irrigação, analisando-se a melhor forma de amortização.This work aimed to evaluate the use of a variable frequency drive of 25 HP in irrigation systems to manage different water demands. The evaluation was done analyzing annual costs and benefits. The cost was calculated using interest rates of 6 and 12% and capital return periods of 5 and 15 years. The benefit was the energy saving by use of the variable frequency drive in relation to usual procedures to control discharge. The economic and irrigation management parameters were compared in order to evaluate several design situations. As an example, two situations of discharge control were compared with the use of a variable frequency drive in an irrigation project, suggesting forms for evaluation of the equipment under irrigated conditions. With the help

  19. Generalized expressions for variations in critical frequencies, electron densities and altitudes of the ionospheric layers

    International Nuclear Information System (INIS)

    Njau, E.C.

    1990-12-01

    We develop generalized mathematical expressions for time and space variations of peak electron densities of the ionospheric D, E, F1 and F2 layers as well as corresponding variations in the altitudes of the electron density peaks in each of these layers. On the basis of the Chapman characteristics of the E and F1 layers and other techniques, a generalized expression is developed for the electron density height profile of each of the four ionospheric layers. Consequently a generalized mathematical expression is developed for the entire electron density height profile of the whole ionosphere as a function of time, latitude and longitude. The latter mathematical expression may be used to compute or predict ionospheric parameters associated with ratio and satellite communications. Finally we show that some well documented equations on ionospheric parameters are simplified (or approximated) versions of some of our mathematical expressions. (author). 29 refs

  20. The Road to Language Learning Is Not Entirely Iconic: Iconicity, Neighborhood Density, and Frequency Facilitate Acquisition of Sign Language.

    Science.gov (United States)

    Caselli, Naomi K; Pyers, Jennie E

    2017-07-01

    Iconic mappings between words and their meanings are far more prevalent than once estimated and seem to support children's acquisition of new words, spoken or signed. We asked whether iconicity's prevalence in sign language overshadows two other factors known to support the acquisition of spoken vocabulary: neighborhood density (the number of lexical items phonologically similar to the target) and lexical frequency. Using mixed-effects logistic regressions, we reanalyzed 58 parental reports of native-signing deaf children's productive acquisition of 332 signs in American Sign Language (ASL; Anderson & Reilly, 2002) and found that iconicity, neighborhood density, and lexical frequency independently facilitated vocabulary acquisition. Despite differences in iconicity and phonological structure between signed and spoken language, signing children, like children learning a spoken language, track statistical information about lexical items and their phonological properties and leverage this information to expand their vocabulary.

  1. Effects of irrigation strategies and soils on field grown potatoes

    DEFF Research Database (Denmark)

    Ahmadi, Seyed Hamid; Plauborg, Finn; Andersen, Mathias Neumann

    2011-01-01

    Root distribution of field grown potatoes (cv. Folva) was studied in 4.32m2 lysimeters and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. Drip irrigation was applied for all irrigations. Irrigations were run in three different soils: coarse sand......, loamy sand, and sandy loam. Irrigation treatments started after tuber bulking and lasted until final harvest with PRD and DI receiving 65% of FI. Potatoes irrigated with water-saving irrigation techniques (PRD and DI) did not show statistically different dry root mass and root length density (RLD, cm...... density in the furrow. Most roots accumulated in the surface layers of coarse sand as compared to the other soil types. In the deep soil profile (30–70 cm) a higher root density was found in loamy sand compared with the sandy loam and coarse sand. Approximately twice the amounts of roots were found below...

  2. Determining the von Mises stress power spectral density for frequency domain fatigue analysis including out-of-phase stress components

    Science.gov (United States)

    Bonte, M. H. A.; de Boer, A.; Liebregts, R.

    2007-04-01

    This paper provides a new formula to take into account phase differences in the determination of an equivalent von Mises stress power spectral density (PSD) from multiple random inputs. The obtained von Mises PSD can subsequently be used for fatigue analysis. The formula was derived for use in the commercial vehicle business and was implemented in combination with Finite Element software to predict and analyse fatigue failure in the frequency domain.

  3. Mapping of trap densities and hotspots in pentacene thin-film transistors by frequency-resolved scanning photoresponse microscopy.

    Science.gov (United States)

    Westermeier, Christian; Fiebig, Matthias; Nickel, Bert

    2013-10-25

    Frequency-resolved scanning photoresponse microscopy of pentacene thin-film transistors is reported. The photoresponse pattern maps the in-plane distribution of trap states which is superimposed by the level of trap filling adjusted by the gate voltage of the transistor. Local hotspots in the photoresponse map thus indicate areas of high trap densities within the pentacene thin film. © 2013 WILEY-VCH Verlag GmbH 8 Co. KGaA, Weinheim.

  4. Multisensory representation of frequency across audition and touch: high density electrical mapping reveals early sensory-perceptual coupling.

    Science.gov (United States)

    Butler, John S; Foxe, John J; Fiebelkorn, Ian C; Mercier, Manuel R; Molholm, Sophie

    2012-10-31

    The frequency of environmental vibrations is sampled by two of the major sensory systems, audition and touch, notwithstanding that these signals are transduced through very different physical media and entirely separate sensory epithelia. Psychophysical studies have shown that manipulating frequency in audition or touch can have a significant cross-sensory impact on perceived frequency in the other sensory system, pointing to intimate links between these senses during computation of frequency. In this regard, the frequency of a vibratory event can be thought of as a multisensory perceptual construct. In turn, electrophysiological studies point to temporally early multisensory interactions that occur in hierarchically early sensory regions where convergent inputs from the auditory and somatosensory systems are to be found. A key question pertains to the level of processing at which the multisensory integration of featural information, such as frequency, occurs. Do the sensory systems calculate frequency independently before this information is combined, or is this feature calculated in an integrated fashion during preattentive sensory processing? The well characterized mismatch negativity, an electrophysiological response that indexes preattentive detection of a change within the context of a regular pattern of stimulation, served as our dependent measure. High-density electrophysiological recordings were made in humans while they were presented with separate blocks of somatosensory, auditory, and audio-somatosensory "standards" and "deviants," where the deviant differed in frequency. Multisensory effects were identified beginning at ∼200 ms, with the multisensory mismatch negativity (MMN) significantly different from the sum of the unisensory MMNs. This provides compelling evidence for preattentive coupling between the somatosensory and auditory channels in the cortical representation of frequency.

  5. Assessment of the effect of three-dimensional mantle density heterogeneity on Earth rotation in tidal frequencies

    Directory of Open Access Journals (Sweden)

    Lanbo Liu

    2016-11-01

    Full Text Available In this paper, we report the assessment of the effect of the three-dimensional (3D density heterogeneity in the mantle on Earth orientation parameters (EOP (i.e., the polar motion, or PM, and the length of day, or LOD in the tidal frequencies. The 3D mantle density model is estimated based upon a global S-wave velocity tomography model (S16U6L8 and the mineralogical knowledge derived from laboratory experiment. The lateral density variation is referenced against the preliminary reference earth model (PREM. Using this approach the effects of the heterogeneous mantle density variation in all three tidal frequencies (zonal long periods, tesseral diurnal, and sectorial semidiurnal are estimated in both PM and LOD. When compared with mass or density perturbations originated on the Earth's surface such as the oceanic and barometric changes, the heterogeneous mantle contributes less than 10% of the total variation in PM and LOD in tidal frequencies. However, this is the gap that has not been explained to close the gap of the observation and modeling in PM and LOD. By computing the PM and LOD caused by 3D heterogeneity of the mantle during the period of continuous space geodetic measurement campaigns (e.g., CONT94 and the contribution from ocean tides as predicted by tide models derived from satellite altimetry observations (e.g., TOPEX/Poseidon in the same period, we got the lump-sum values of PM and LOD. The computed total effects and the observed PM and LOD are generally agree with each other. In another word, the difference of the observed PM and LOD and the model only considering ocean tides, at all tidal frequencies (long periods, diurnals, and semidiurnals contains the contributions of the lateral density heterogeneity of the mantle. Study of the effect of mantle density heterogeneity effect on torque-free Earth rotation may provide useful constraints to construct the reference earth model (REM, which is the next major objective in global

  6. Irrigation and Autocracy

    DEFF Research Database (Denmark)

    Bentzen, Jeanet Sinding; Kaarsen, Nicolai; Wingender, Asger Moll

    We show that societies with a history of irrigation-based agriculture have been less likely to adopt democracy than societies with a history of rainfed agriculture. Rather than actual irrigation, the empirical analysis is based on how much irrigation potentially can increase yields.Irrigation pot...

  7. Identifying dielectric and resistive electrode losses in high-density capacitors at radio frequencies

    NARCIS (Netherlands)

    Tiggelman, M.P.J.; Reimann, K.; Liu, J.; Klee, M.; Keur, W.; Mauczock, R.; Schmitz, Jurriaan; Hueting, Raymond Josephus Engelbart

    2008-01-01

    A regression-based technique is presented which distinguishes the dielectric loss from the resistive loss of high density planar capacitors in a very wide bandwidth of 0.1–8 GHz. Moreover, the procedure yields useful results if the capacitor deviates from a lumped element model and indicates when

  8. Studying Geographical Distribution Map of Weeds of Irrigated Wheat Fields of Ardabil Province

    Directory of Open Access Journals (Sweden)

    B Soheili

    2013-12-01

    Full Text Available In order to identify the density and abundance of weeds in irrigated wheat fields of Ardabil Province, 76 samples of irrigated wheat fields based on cultivation area from all counties of Ardabil province for six years (2001-2006 were selected. The genus and species of weeds from each sampling fields and their population indices density, frequency and uniformity of each species were calculated by using Thomas method. Geographic coordinates of field (Latitude, Altitude and Elevation were the main coverage and were determined by using GPS. These data were used for producing weed maps using GIS in irrigated wheat fields of Ardabil province. Results showed that bedstraw (Galium tricurnatum, Fumitory(Fumaria vaillantiand wildradish (Raphanus raphanistrum were dominant broad leaf weed species and wild oats (Avena fatua, rye (Secale cereal and mouse foxtail(Alopecurus myosuroides dominant grassy weeds species in irrigated wheat fields of Ardabil province. Bindweed (Convolvulus arvensis, Canada thistle(Cirsium arvenseand Acroptilon repens were the most important disturbing plants prior to harvesting in irrigated wheat fields of Ardabil province.

  9. The phenology of malaria mosquitos in irrigated rice fields in Mali

    NARCIS (Netherlands)

    Klinkenberg, E.; Takken, W.; Huibers, F.P.; Touré, Y.T.

    2003-01-01

    A field study was carried out in the large-scale rice irrigation scheme of the Office du Niger in Mali to investigate the relation between anopheline mosquito larval development and small-scale differences in irrigation practices, such as water level, irrigation application and irrigation frequency.

  10. A geographical model of radio-frequency power density around mobile phone masts

    International Nuclear Information System (INIS)

    Briggs, David; Beale, Linda; Bennett, James; Toledano, Mireille B.; Hoogh, Kees de

    2012-01-01

    Public concern about possible health effects of EMF radiation from mobile phone masts has led to an increase of epidemiological studies and health risk assessments which, in turn, require adequate methods of exposure estimation. Difficulties in exposure modelling are exacerbated both by the complexity of the propagation processes, and the need to obtain estimates for large study populations in order to provide sufficient statistical power to detect or exclude the small relative risks that might exist. Use of geographical information system (GIS) techniques offers the means to make such computations efficiently. This paper describes the development and field validation of a GIS-based exposure model (Geomorf). The model uses a modified Gaussian formulation to represent spatial variations in power densities around mobile phone masts, on the basis of power output, antenna height, tilt and the surrounding propagation environment. Obstruction by topography is allowed for, through use of a visibility function. Model calibration was done using field data from 151 measurement sites (1510 antenna-specific measurements) around a group of masts in a rural location, and 50 measurement sites (658 antenna-specific measurements) in an urban area. Different parameter settings were found to be necessary in urban and rural areas to obtain optimum results. The calibrated models were then validated against independent sets of data gathered from measurement surveys in rural and urban areas, and model performance was compared with that of two commonly used path-loss models (the COST-231 adaptations of the Hata and Walfisch–Ikegami models). Model performance was found to vary somewhat between the rural and urban areas, and at different measurement levels (antenna-specific power density, total power density), but overall gave good estimates (R 2 = 0.641 and 0.615, RMSE = 10.7 and 6.7 dB m at the antenna and site-level respectively). Performance was considerably better than that of both

  11. Topographic power spectral density study of the effect of surface treatment processes on niobium for superconducting radio frequency accelerator cavities

    Science.gov (United States)

    Xu, Chen; Tian, Hui; Reece, Charles E.; Kelley, Michael J.

    2012-04-01

    Microroughness is viewed as a critical issue for attaining optimum performance of superconducting radio frequency accelerator cavities. The principal surface smoothing methods are buffered chemical polish (BCP) and electropolish (EP). The resulting topography is characterized by atomic force microscopy (AFM). The power spectral density (PSD) of AFM data provides a more thorough description of the topography than a single-value roughness measurement. In this work, one dimensional average PSD functions derived from topography of BCP and EP with different controlled starting conditions and durations have been fitted with a combination of power law, K correlation, and shifted Gaussian models to extract characteristic parameters at different spatial harmonic scales. While the simplest characterizations of these data are not new, the systematic tracking of scale-specific roughness as a function of processing is new and offers feedback for tighter process prescriptions more knowledgably targeted at beneficial niobium topography for superconducting radio frequency applications.

  12. Topographic power spectral density study of the effect of surface treatment processes on niobium for superconducting radio frequency accelerator cavities

    International Nuclear Information System (INIS)

    Reece, Charles; Tian, Hui; Kelley, Michael; Xu, Chen

    2012-01-01

    Microroughness is viewed as a critical issue for attaining optimum performance of superconducting radio frequency accelerator cavities. The principal surface smoothing methods are buffered chemical polish (BCP) and electropolish (EP). The resulting topography is characterized by atomic force microscopy (AFM). The power spectral density (PSD) of AFM data provides a more thorough description of the topography than a single-value roughness measurement. In this work, one dimensional average PSD functions derived from topography of BCP and EP with different controlled starting conditions and durations have been fitted with a combination of power law, K correlation, and shifted Gaussian models to extract characteristic parameters at different spatial harmonic scales. While the simplest characterizations of these data are not new, the systematic tracking of scale-specific roughness as a function of processing is new and offers feedback for tighter process prescriptions more knowledgably targeted at beneficial niobium topography for superconducting radio frequency applications.

  13. Calculation of the intrinsic spectral density of current fluctuations in nanometric Schottky-barrier diodes at terahertz frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Mahi, F.Z. [Science and Technology Institute, University of Bechar, 08000 Bechar (Algeria)], E-mail: fati_zo_mahi2002@yahoo.fr; Helmaoui, A. [Science and Technology Institute, University of Bechar, 08000 Bechar (Algeria); Varani, L. [Institut d' Electronique du Sud (CNRS UMR 5214), Universite Montpellier II, 34095 Montpellier (France); Shiktorov, P.; Starikov, E.; Gruzhinskis, V. [Semiconductor Physics Institute, 01108 Vilnius (Lithuania)

    2008-10-01

    An analytical model for the noise spectrum of nanometric Schottky-barrier diodes (SBD) is developed. The calculated frequency dependence of the spectral density of current fluctuations exhibits resonances in the terahertz domain which are discussed and analyzed as functions of the length of the diode, free carrier concentration, length of the depletion region and applied voltage. A good agreement obtained with direct Monte Carlo simulations of GaAs SBDs operating from barrier-limited to flat-band conditions fully validates the proposed approach.

  14. An analysis of instabilities of nuclear-coupled density-wave in BWR using modern frequency-domain control theory

    International Nuclear Information System (INIS)

    Zhao Yangping; Gao Huahun; Fu Longzhou

    1991-01-01

    A state-of-the-art multi-variable frequency-domain model has been developed for analysis of instabilities of nuclear-coupled density-wave in BWR core. The characteristic locus method is used for analysing the stability of BWR. A computer code-NUCTHIA has been derived. The model has been tested against the existing experimental data and compared with results of past single-variable analyses. By using the NUCTHIA code, the investigations of effects of main system parameters on BWW core stability have also been made. All the results are consistent with the experimental data

  15. Effects of irrigation on the seasonal abundance of Empoasca vitis in north-Italian vineyards.

    Science.gov (United States)

    Fornasiero, D; Duso, C; Pozzebon, A; Tomasi, D; Gaiotti, F; Pavan, F

    2012-02-01

    The effect of irrigation on the abundance of Empoasca vitis (Göthe) populations was investigated in four vineyards located in northeastern Italy. In two experiments, we compared leafhopper population densities in plots irrigated (micro-spray irrigation system) or nonirrigated. In another experiment, we studied the effect of various irrigation systems on E. vitis populations over two successive seasons. In particular, five treatments were compared: control (not irrigated), traditional drip system, three types of subirrigation varying in distance from the row (40, 135, and 95 cm). In this vineyard, stem water potential was monitored with a pressure chamber. E. vitis population densities were affected by irrigation, with higher densities of this pest recorded on irrigated vines. Highest E. vitis densities were detected in drip irrigation plots compared with nonirrigated plots where water stress was highest. Moderate water stress (subirrigation plots) was associated with intermediate leafhopper densities. Implications for integrated pest management are discussed.

  16. Ghana - Agriculture - Irrigation

    Data.gov (United States)

    Millennium Challenge Corporation — The Millennium Development Authority (MiDA) financed the construction of a new irrigation scheme in Kpong and the renovation of two irrigation schemes in Botanga and...

  17. Outdoor stocking density in free-range laying hens: radio-frequency identification of impacts on range use.

    Science.gov (United States)

    Campbell, D L M; Hinch, G N; Dyall, T R; Warin, L; Little, B A; Lee, C

    2017-01-01

    The number and size of free-range laying hen (Gallus gallus domesticus) production systems are increasing within Australia in response to consumer demand for perceived improvement in hen welfare. However, variation in outdoor stocking density has generated consumer dissatisfaction leading to the development of a national information standard on free-range egg labelling by the Australian Consumer Affairs Ministers. The current Australian Model Code of Practice for Domestic Poultry states a guideline of 1500 hens/ha, but no maximum density is set. Radio-frequency identification (RFID) tracking technology was used to measure daily range usage by individual ISA Brown hens housed in six small flocks (150 hens/flock - 50% of hens tagged), each with access to one of three outdoor stocking density treatments (two replicates per treatment: 2000, 10 000, 20 000 hens/ha), from 22 to 26, 27 to 31 and 32 to 36 weeks of age. There was some variation in range usage across the sampling periods and by weeks 32 to 36 individual hens from the lowest stocking density on average used the range for longer each day (Prange with 2% of tagged hens in each treatment never venturing outdoors and a large proportion that accessed the range daily (2000 hens/ha: 80.5%; 10 000 hens/ha: 66.5%; 20 000 hens/ha: 71.4%). On average, 38% to 48% of hens were seen on the range simultaneously and used all available areas of all ranges. These results of experimental-sized flocks have implications for determining optimal outdoor stocking densities for commercial free-range laying hens but further research would be needed to determine the effects of increased range usage on hen welfare.

  18. Root canal irrigants

    OpenAIRE

    Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu

    2010-01-01

    Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are...

  19. IRRIGATION USING SOLAR PUMP

    OpenAIRE

    Prof. Nitin P.Choudhary*1 & Ms. Komal Singne2

    2017-01-01

    In this report the described design of a PV and soil moisture sensor based automated irrigation system is introduced. This project aims to provide a human friendly, economical and automated water pumping system which eliminates the problems of over irrigation and helps in irrigation water optimization and manage it in accordance with the availability of water. Our project not only tries to modernize the irrigation practices and ensure the optimum yield by carefully fulfilling the requirements...

  20. DENSITY OF WARM IONIZED GAS NEAR THE GALACTIC CENTER: LOW RADIO FREQUENCY OBSERVATIONS

    International Nuclear Information System (INIS)

    Roy, Subhashis

    2013-01-01

    We have observed the Galactic center (GC) region at 0.154 and 0.255 GHz with the Giant Metrewave Radio Telescope. A total of 62 compact likely extragalactic (EG) sources are detected. Their scattering sizes decrease linearly with increasing angular distance from the GC up to about 1°. The apparent scattering sizes of the sources are more than an order of magnitude less than predicted earlier by the NE2001 model of Galactic electron distribution within 359.°5 e is ∼10 cm –3 , which matches the NE2001 model. This model predicts the EG sources to be resolved out from 1.4 GHz interferometric surveys. However, out of 10 EG sources expected in the region, 8 likely EG are present in the 1.4 GHz catalog. Ionized interfaces of dense molecular clouds to the ambient medium are most likely responsible for strong scattering and low radio frequency absorption. However, dense GC clouds traced by CS J = 1-0 emission are found to have a narrow distribution of ∼0.°2 across the Galactic plane. Angular distribution of most EG sources seen through the so-called Hyperstrong Scattering Region are random in b, and typically ∼7 out of 10 sources will not be seen through the dense molecular clouds, which explains why most of them are not scatter broadened at 1.4 GHz

  1. Irrigation in endodontic treatment.

    Science.gov (United States)

    Basrani, Bettina

    2011-01-01

    The primary endodontic treatment goal is to optimize root canal disinfection and to prevent reinfection. Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal system. In this review of the literature, various irrigants and the interactions between irrigants are discussed and new delivery systems are introduced.

  2. Progresso da ferrugem do cafeeiro irrigado em diferentes densidades de plantio pós-poda Progress of rust in coffee plants in various densities of cultivation in irrigated planting after pruning

    Directory of Open Access Journals (Sweden)

    Bernardo Reis Teixeira Lacerda Paiva

    2011-02-01

    Full Text Available Objetivou-se, no presente trabalho, avaliar o efeito de diferentes critérios para manejo da irrigação em quatro densidades de plantio, sob sistema de gotejamento na incidência e severidade da ferrugem do cafeeiro e avaliar a influência do enfolhamento na curva de progresso dessa doença. Conduziu-se, o experimento, em área experimental da Universidade Federal de Lavras MG, utilizando a cultivar Rubi MG-1192 com seis anos. O delineamento experimental foi em blocos ao acaso com quatro repetições. Os tratamentos foram constituídos por quatro parcelas representadas pelas densidades de plantio (convencionais e adensados: 2500 (4,0x1,0 m, 3333 (3,0x1,0 m, 5000 (2,0x1,0 m, 10000 (2,0x0,5 m plantas ha-1, quatro subparcelas sendo: irrigações quando a tensão da água no solo atingiu valores de 20 e 60kPa; irrigações utilizando o manejo do balanço hídrico (calculado através do software IRRIPLUS, com turnos de irrigação fixos de três dias por semana e uma testemunha sem irrigação, perfazendo um total de 16 tratamentos. Cada subparcela foi constituída por 10 plantas, sendo consideradas como plantas úteis as seis centrais. Foram avaliadas a incidência e severidade da ferrugem e a porcentagem de enfolhamento das plantas de cafeeiros. Após análise estatística, os dados foram convertidos em área abaixo da curva de progresso da doença e do crescimento. Verificou-se que os critérios para manejo da irrigação influenciaram a curva de progresso do crescimento, porém, não interferiu na curva de progresso da incidência e da severidade da ferrugem. Os sistemas de plantios adensados favoreceram a incidência da ferrugem. Mas as densidades de plantio não interferiram no enfolhamento.The objective of this study was to evaluate the effect of different irrigation controls implemented in four planting densities on a system of drip on the incidence and severity of rust and to assess the influence of leaf growth on the progress curve of this

  3. High frequency P(VDF-TrFE) copolymer broadband annular array ultrasound transducers using high density flexible circuit interconnect

    Science.gov (United States)

    Gottlieb, Emanuel J.; Cannata, Jonathan M.; Hu, Chang Hong; Shung, K. K.

    2005-04-01

    A kerfless eight element high frequency ultrasound annular array transducer using 9 μm P(VDF-TrFE) bonded to a high density flexible interconnect was fabricated. The flexible circuit composed of Kapton polyimide film with gold electrode pattern of equal area annuli apertures on the top side of a 50 μm thick Kapton polyimide film. Each element had several 30 μm diameter electroplated vias that connected to electrode traces on the bottom side of the Kapton polyimide film. There was a 30 μm spacing between elements. The total aperture of the array was 3.12 mm. The transducer's performance has been modeled by implementing the Redwood version of the Mason model into PSpice and using the Krimholtz, Leedom and Matthaei (KLM) model utilized in the commercial software PiezoCAD. The transducer"s performance was evaluated by measuring the electrical impedance with a HP 4194 impedance analyzer, pulse echo response using a Panametrics 5900 pulser/receiver and crosstalk measurement for each element in the array. The measured electrical impedance for each element was 540 Ω and -84° phase. In order to improve device sensitivity an inductor was attached in series with each element to reduce the insertion loss to 33 dB. The measured average center frequency and bandwidth of each element was 55 MHz and 50% respectively. The measured crosstalk at the center frequency was -45 dB in water.

  4. Characterization of Anodized Titanium Based Novel Paradigm Supercapacitors: Impact of Salt Identity and Frequency on Dielectric Values, Power, and Energy Densities

    Science.gov (United States)

    2017-03-01

    solution, sufficient charge carriers to counteract the applied but not cause ion- lock , are energy densities at their maximum. For the salt identities and...OF ANODIZED TITANIUM- BASED NOVEL PARADIGM SUPERCAPACITORS: IMPACT OF SALT IDENTITY AND FREQUENCY ON DIELECTRIC VALUES, POWER, AND ENERGY DENSITIES...SUBTITLE CHARACTERIZATION OF ANODIZED TITANIUM-BASED NOVEL PARADIGM SUPERCAPACITORS: IMPACT OF SALT IDENTITY AND FREQUENCY ON DIELECTRIC VALUES, POWER

  5. The roles of word-form frequency and phonological neighbourhood density in the acquisition of Lithuanian noun morphology.

    Science.gov (United States)

    Savičiūtė, Eglė; Ambridge, Ben; Pine, Julian M

    2018-05-01

    Four- and five-year-old children took part in an elicited familiar and novel Lithuanian noun production task to test predictions of input-based accounts of the acquisition of inflectional morphology. Two major findings emerged. First, as predicted by input-based accounts, correct production rates were correlated with the input frequency of the target form, and with the phonological neighbourhood density of the noun. Second, the error patterns were not compatible with the systematic substitution of target forms by either (a) the most frequent form of that noun or (b) a single morphosyntactic default form, as might be predicted by naive versions of a constructivist and generativist account, respectively. Rather, most errors reflected near-miss substitutions of singular for plural, masculine for feminine, or nominative/accusative for a less frequent case. Together, these findings provide support for an input-based approach to morphological acquisition, but are not adequately explained by any single account in its current form.

  6. Irrigating The Environment

    Science.gov (United States)

    Adamson, D.

    2017-12-01

    Water insecurity and water inequality are international issues that reduce economic growth. Countries are adopting alternative approaches to rebalance the share of water between all users to mitigate economic loss for this and future generations. However, recent reforms have struggled to provide the necessary arguments to obtain political protection of the process. In the absence of proof, rent-seeking arguments have challenged the benefit of restoring environmental flows by arguing that policy design fails to maximise the environmental benefits. This is a problem in Australia's Murray-Darling Basin (MDB), where despite establishing 3,200GL of environmental water, the policy is still under threat. Applied water economic policy advice fails, when it does not deal with uncertainty. The state-contingent analysis approach can map how individual decision makers can adapt to alternative states of water supply (i.e. drought, normal and wet) by reallocating inputs to obtain state-described outputs. By modelling changes to the states, or the frequency of the states occurring, climate change can modelled, and decision management responses explored. By treating the environment as another set of production systems, lessons learnt from managing perennial and annual agricultural production systems during the Millennium Drought in the MDB can be applied to explore the limits of irrigating the environment. The demand for water by a production system is a combination of state-general (must be irrigated every year e.g. perennial crop or permanent wetland) and state specific inputs (irrigate in response to the realise state). In simple terms, the greater the component of state-general water requirements a production system has, the less resilience it has when water supply is highly variable and if water is not available then production systems are irreversibly lost. While production systems that only need state-allocable water can adapt to alternative levels of scarcity without

  7. Low-Frequency Raman Modes of 2H-TaSe2 in the Charge Density Wave Phase

    Science.gov (United States)

    Chowdhury, Sugata; Simpson, J.; Einstein, T. L.; Hight Walker, A. R.; Theoretical Collaboration

    With changes in temperatures, tantalum diselenide (2H-TaSe2) , a layered, transition metal chalcogenides (TMD) exhibits unique super-lattice structures. The metallic ground state changes to an incommensurate charge density wave (CDW) state at 122?K followed by a commensurate CDW state at 90?K, and eventually a superconducting state 0.14 K. These phase transitions are driven by strong electron-phonon coupling and favored by the particular form of the Fermi surface of these systems. Here we theoretically studied the structural origin of low-frequency Raman modes of bulk 2H-TaSe2\\ in the CDW phases. Our calculations reveal that changes observed in the Raman modes are associated with the thermal expansion in the basal plane of 2H-TaSe2. The Grüneisen parameters of these two Raman modes increase in the CDW phases. Changes in the lattice parameter ``a'' are large compared to ``c'' which induces strain along the a-axis. We compared our results with experimental data which show low-frequency Raman phonon modes are very sensitive to temperature and are not observed in the metallic room-temperature state. In addition, we found that cation displacement is more than anion in CDW phase. Our results may shed more light on exact nature of the CDW instability and optical properties in this system.

  8. The Regularity of Optimal Irrigation Patterns

    Science.gov (United States)

    Morel, Jean-Michel; Santambrogio, Filippo

    2010-02-01

    A branched structure is observable in draining and irrigation systems, in electric power supply systems, and in natural objects like blood vessels, the river basins or the trees. Recent approaches of these networks derive their branched structure from an energy functional whose essential feature is to favor wide routes. Given a flow s in a river, a road, a tube or a wire, the transportation cost per unit length is supposed in these models to be proportional to s α with 0 measure is the Lebesgue density on a smooth open set and the irrigating measure is a single source. In that case we prove that all branches of optimal irrigation trees satisfy an elliptic equation and that their curvature is a bounded measure. In consequence all branching points in the network have a tangent cone made of a finite number of segments, and all other points have a tangent. An explicit counterexample disproves these regularity properties for non-Lebesgue irrigated measures.

  9. On the role of density and attenuation in three-dimensional multiparameter viscoacoustic VTI frequency-domain FWI: an OBC case study from the North Sea

    Science.gov (United States)

    Operto, S.; Miniussi, A.

    2018-06-01

    3-D frequency-domain full waveform inversion (FWI) is applied on North Sea wide-azimuth ocean-bottom cable data at low frequencies (≤10 Hz) to jointly update vertical wave speed, density and quality factor Q in the viscoacoustic VTI approximation. We assess whether density and Q should be viewed as proxy to absorb artefacts resulting from approximate wave physics or are valuable for interpretation in the presence of soft sediments and gas cloud. FWI is performed in the frequency domain to account for attenuation easily. Multiparameter frequency-domain FWI is efficiently performed with a few discrete frequencies following a multiscale frequency continuation. However, grouping a few frequencies during each multiscale step is necessary to mitigate acquisition footprint and match dispersive shallow guided waves. Q and density absorb a significant part of the acquisition footprint hence cleaning the velocity model from this pollution. Low Q perturbations correlate with low-velocity zones associated with soft sediments and gas cloud. However, the amplitudes of the Q perturbations show significant variations when the inversion tuning is modified. This dispersion in the Q reconstructions is however not passed on the velocity parameter suggesting that cross-talks between first-order kinematic and second-order dynamic parameters are limited. The density model shows a good match with a well log at shallow depths. Moreover, the impedance built a posteriori from the FWI velocity and density models shows a well-focused image with however local differences with the velocity model near the sea bed where density might have absorbed elastic effects. The FWI models are finally assessed against time-domain synthetic seismogram modelling performed with the same frequency-domain modelling engine used for FWI.

  10. Armenia - Irrigation Infrastructure

    Data.gov (United States)

    Millennium Challenge Corporation — This study evaluates irrigation infrastructure rehabilitation in Armenia. The study separately examines the impacts of tertiary canals and other large infrastructure...

  11. Irrigation and Autocracy

    DEFF Research Database (Denmark)

    Bentzen, Jeanet Sinding; Kaarsen, Nicolai; Wingender, Asger Moll

    2017-01-01

    . We argue that the effect has historical origins: irrigation allowed landed elites in arid areas to monopolize water and arable land. This made elites more powerful and better able to oppose democratization. Consistent with this conjecture, we show that irrigation dependence predicts land inequality...

  12. Effective colostomy irrigation.

    Science.gov (United States)

    Mazier, W P; Dignan, R D; Capehart, R J; Smith, B G

    1976-06-01

    The ultimate goal of the cone method of colostomy irrigation is to return patients with colostomies to their former role in society with confidence in themselves to the extent that having a colostomy is not considered a handicap. The results have generally been excellent. We believe all patients with stomas should be afforded the opportunity to attempt colostomy irrigation.

  13. Effects of ten years treated wastewater drip irrigation on soil ...

    African Journals Online (AJOL)

    SWEET

    soil contamination and the cumulative impact of wastewater, we compared two plots, all under orange- ... A slight increase in the concentration of soil enteric bacteria and soil fungal densities was ..... could be used for fruit tree irrigation.

  14. Density distribution of currents induced inside the brain in the head part of the human model exposed to power frequency electric field

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, Atsuo [Yongo National Collage of Technology (Japan); Isaka, Katsuo [University of Tokushima (Japan)

    1999-07-01

    The health effect of the weak current induced in the human body as a result of the interaction between human body and power frequency electric fields has been investigated. However, the current density inside the head part tissues of the human body exposed to the electric fields has rarely been discussed. In this paper, the finite element method is applied to the analysis of the current density distribution of the head part composed of scalp, skull, cerebrospinal liquid and brain tissues. The basic characteristics of the current density distributions of the brain in the asymmetrical human model have been made clear. (author)

  15. Molecular Structure And Vibrational Frequencies of 2,3,4 Nitro anilines By Hartree-Fock And Density Functional Theory Calculations

    International Nuclear Information System (INIS)

    Sert, Y.

    2008-01-01

    The optimised molecular structure, vibrational frequencies and corresponding vibrational assignments of 2-, 3- and 4- nitro anilines have been calculated using the Hartree-Fock (HF) and density functional methods (B3LYP) with 6-311++G (d, p) basis set. The calculations were adapted to the C S symmetries of all the molecules. The calculated vibrational frequencies and geometric parameters (bond lengths and bond angles) were seen to be in good agreement with the experimental data. The comparison of the experimental and theoretical results showed that the HF method is superior to the B3LYP method for both the vibrational frequencies and geometric parameters

  16. Energy-density field approach for low- and medium-frequency vibroacoustic analysis of complex structures using a statistical computational model

    Science.gov (United States)

    Kassem, M.; Soize, C.; Gagliardini, L.

    2009-06-01

    In this paper, an energy-density field approach applied to the vibroacoustic analysis of complex industrial structures in the low- and medium-frequency ranges is presented. This approach uses a statistical computational model. The analyzed system consists of an automotive vehicle structure coupled with its internal acoustic cavity. The objective of this paper is to make use of the statistical properties of the frequency response functions of the vibroacoustic system observed from previous experimental and numerical work. The frequency response functions are expressed in terms of a dimensionless matrix which is estimated using the proposed energy approach. Using this dimensionless matrix, a simplified vibroacoustic model is proposed.

  17. Colonic irrigation for defecation disorders after dynamic graciloplasty.

    Science.gov (United States)

    Koch, Sacha M; Uludağ, Ozenç; El Naggar, Kadri; van Gemert, Wim G; Baeten, Cor G

    2008-02-01

    Dynamic graciloplasty (DGP) improves anal continence and quality of life for most patients. However, in some patients, DGP fails and fecal incontinence is unsolved or only partially improved. Constipation is also a significant problem after DGP, occurring in 13-90%. Colonic irrigation can be considered as an additional or salvage treatment for defecation disorders after unsuccessful or partially successful DGP. In this study, the effectiveness of colonic irrigation for the treatment of persistent fecal incontinence and/or constipation after DGP is investigated. Patients with defecation disorders after DGP visiting the outpatient clinic of the University Hospital Maastricht were selected for colonic irrigation as additional therapy or salvage therapy in the period between January 1999 and June 2003. The Biotrol(R) Irrimatic pump or the irrigation bag was used for colonic irrigation. Relevant physical and medical history was collected. The patients were asked to fill out a detailed questionnaire about colonic irrigation. Forty-six patients were included in the study with a mean age of 59.3 +/- 12.4 years (80% female). On average, the patients started the irrigation 21.39 +/- 38.77 months after the DGP. Eight patients started irrigation before the DGP. Fifty-two percent of the patients used the irrigation as additional therapy for fecal incontinence, 24% for constipation, and 24% for both. Irrigation was usually performed in the morning. The mean frequency of irrigation was 0.90 +/- 0.40 times per day. The mean amount of water used for the irrigation was 2.27 +/- 1.75 l with a mean duration of 39 +/- 23 min. Four patients performed antegrade irrigation through a colostomy or appendicostomy, with good results. Overall, 81% of the patients were satisfied with the irrigation. Thirty-seven percent of the patients with fecal incontinence reached (pseudo-)continence, and in 30% of the patients, the constipation completely resolved. Side effects of the irrigation were

  18. Numerical studies of independent control of electron density and gas temperature via nonlinear coupling in dual-frequency atmospheric pressure dielectric barrier discharge plasmas

    International Nuclear Information System (INIS)

    Zhang, Z. L.; Nie, Q. Y.; Wang, Z. B.; Gao, X. T.; Kong, F. R.; Sun, Y. F.; Jiang, B. H.

    2016-01-01

    Dielectric barrier discharges (DBDs) provide a promising technology of generating non-equilibrium cold plasmas in atmospheric pressure gases. For both application-focused and fundamental studies, it is important to explore the strategy and the mechanism for enabling effective independent tuning of key plasma parameters in a DBD system. In this paper, we report numerical studies of effects of dual-frequency excitation on atmospheric DBDs, and modulation as well as separate tuning mechanism, with emphasis on dual-frequency coupling to the key plasma parameters and discharge evolution. With an appropriately applied low frequency to the original high frequency, the numerical calculation demonstrates that a strong nonlinear coupling between two frequencies governs the process of ionization and energy deposition into plasma, and thus raises the electron density significantly (e.g., three times in this case) in comparisons with a single frequency driven DBD system. Nevertheless, the gas temperature, which is mainly determined by the high frequency discharge, barely changes. This method then enables a possible approach of controlling both averaged electron density and gas temperature independently.

  19. Randomised clinical trial of cryoballoon versus irrigated radio frequency catheter ablation for atrial fibrillation-the effect of double short versus standard exposure cryoablation duration during pulmonary vein isolation (CIRCA-DOSE): methods and rationale.

    Science.gov (United States)

    Andrade, Jason G; Deyell, Marc W; Badra, Mariano; Champagne, Jean; Dubuc, Marc; Leong-Sit, Peter; Macle, Laurent; Novak, Paul; Roux, Jean-Francois; Sapp, John; Tang, Anthony; Verma, Atul; Wells, George A; Khairy, Paul

    2017-10-05

    Pulmonary vein isolation (PVI) is an effective therapy for paroxysmal atrial fibrillation (AF), but it has limitations. The two most significant recent advances have centred on the integration of real-time quantitative assessment of catheter contact force into focal radio frequency (RF) ablation catheters and the development of dedicated ablation tools capable of achieving PVI with a single ablation lesion (Arctic Front cryoballoon, Medtronic, Minneapolis, MN, USA). Although each of these holds promise for improving the clinical success of catheter ablation of AF, there has not been a rigorous comparison of these advanced ablation technologies. Moreover, the optimal duration of cryoablation (freezing time) has not been determined. Patients undergoing an initial PVI procedure for paroxysmal AF will be recruited. Patients will be randomised 1:1:1 between contact-force irrigated RF ablation, short duration cryoballoon ablation (2 min applications) and standard duration cryoballoon ablation (4 min applications). The primary outcome is time to first documented AF recurrence on implantable loop recorder. With a sample size of 111 per group and a two-sided 0.025 significance level (to account for the two main comparisons), the study will have 80% power (using a log-rank test) to detect a difference of 20% between contact force RF catheter ablation and either of the two cryoballoon ablation groups. Factoring in a 4% loss to follow-up, 116 patients per group should be randomised and followed for a year (total study population of 348). The study was approved by the University of British Columbia Office of Research (Services) Ethics Clinical Research Ethics Board. Results of the study will be submitted for publication in a peer-reviewed journal. NCT01913522; Pre-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  20. Resposta de híbridos de milho irrigado à densidade de plantas em três épocas de semeadura Response of irrigated corn hybrids to plant density in three sowing dates

    Directory of Open Access Journals (Sweden)

    Paulo Regis Ferreira da Silva

    1999-04-01

    Full Text Available A determinação da densidade ótima de semeadura do milho, além de ser influenciada pelas características dos híbridos, pelo nível de fertilidade do solo e pela disponibilidade hídrica, pode também variar de acordo com a época da semeadura, uma vez que ela afeta o crescimento e desenvolvimento da planta. Com o objetivo de determinar a densidade ótima de planta em híbridos de milho com elevado potencial de rendimento de grãos, em três épocas de semeadura, com relação a rendimento de grãos, componentes do rendimento e outras características agronômicas, foram feitos quatro experimentos na região fisiográfica da Depressão Central do Rio Grande do Sul, município de Eldorado do Sul, com suplementação hídrica por aspersão. Os tratamentos constaram de quatro híbridos (Pioneer 3063, Pioneer 3207, XL 212 e Cargill 901, quatro densidades de plantas (50, 70, 90 e 110.000 pl/ha e de três épocas de semeadura (agosto, outubro e dezembro. Não há resposta à densidade de plantas dos híbridos de milho testados nas épocas de semeadura de agosto e dezembro. O aumento na densidade de plantas somente foi vantajosa na semeadura de outubro, quando se obtiveram maiores rendimentos de grãos na densidade de 70.000 pl/ha, independentemente do híbrido avaliado, nas duas estações de crescimento.Plant density response of corn besides influenced by hybrids traits, soil fertility level and water availability, could also vary with sowing date, since it affects plant growth and development. With the objective of determining the most adequate plant density of corn hybrids with high potential grain yields, in three sowing dates, in relation to grain yields, yield components and other agronomic traits, four experiments were conducted in the state of Rio Grande do Sul, Brazil, with complementary irrigation. The treatments were composed by four hybrids (Pioneer 3063, Pioneer 3207, XL 212 and Cargill 901, four plant densities (50, 70, 90 and 110

  1. Soft-Decision-Data Reshuffle to Mitigate Pulsed Radio Frequency Interference Impact on Low-Density-Parity-Check Code Performance

    Science.gov (United States)

    Ni, Jianjun David

    2011-01-01

    This presentation briefly discusses a research effort on mitigation techniques of pulsed radio frequency interference (RFI) on a Low-Density-Parity-Check (LDPC) code. This problem is of considerable interest in the context of providing reliable communications to the space vehicle which might suffer severe degradation due to pulsed RFI sources such as large radars. The LDPC code is one of modern forward-error-correction (FEC) codes which have the decoding performance to approach the Shannon Limit. The LDPC code studied here is the AR4JA (2048, 1024) code recommended by the Consultative Committee for Space Data Systems (CCSDS) and it has been chosen for some spacecraft design. Even though this code is designed as a powerful FEC code in the additive white Gaussian noise channel, simulation data and test results show that the performance of this LDPC decoder is severely degraded when exposed to the pulsed RFI specified in the spacecraft s transponder specifications. An analysis work (through modeling and simulation) has been conducted to evaluate the impact of the pulsed RFI and a few implemental techniques have been investigated to mitigate the pulsed RFI impact by reshuffling the soft-decision-data available at the input of the LDPC decoder. The simulation results show that the LDPC decoding performance of codeword error rate (CWER) under pulsed RFI can be improved up to four orders of magnitude through a simple soft-decision-data reshuffle scheme. This study reveals that an error floor of LDPC decoding performance appears around CWER=1E-4 when the proposed technique is applied to mitigate the pulsed RFI impact. The mechanism causing this error floor remains unknown, further investigation is necessary.

  2. Effects of cervical low-frequency electrical stimulation with various waveforms and densities on body mass, liver and kidney function, and death rate in ischemic stroke rats

    Institute of Scientific and Technical Information of China (English)

    Yonghong Yang; Chengqi He; Lin Yang; Qiang Gao; Shasha Li; Jing He

    2011-01-01

    Low-frequency electrical stimulation has resulted in favorable effects in the treatment of post-stroke dysphagia. However, the safety of cervical low-frequency electrical stimulation remains unclear because of numerous nerves and blood vessels in the neck. In the present study, rats with ischemic stroke underwent low-frequency electrical stimulation, and systemic and local effects of electrical stimulation at different densities and waveforms were investigated. Electrical stimulation resulted in no significant effects on body mass, liver or kidney function, or mortality rate. In addition, no significant adverse reaction was observed, despite overly high intensity of low-frequency electrical stimulation, which induced laryngismus, results from the present study suggested that it is safe to stimulate the neck with a low-frequency electricity under certain intensities.

  3. First results from plasma density measurements in the FTU tokamak by means of a two-frequency pulsed time-of-flight refractometer

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, V. G.; Malyshev, A. Yu.; Markov, V. K.; Petrov, A. A. [Troitsk Institute for Innovation and Fusion Research (Russian Federation); Avino, F.; Angelis, R. de; Tudisco, O. [ENEA-UT Fusione Centro Ricerche Frascati (Italy)

    2012-04-15

    A pulsed time-of-flight refractometer was developed and tested to determine the mean plasma density in the T-11M tokamak by measuring the propagation time of nanosecond microwave pulses in plasma. Later, it was also proposed to use such an instrument to measure and control the mean plasma density in the ITER tokamak by probing the plasma with an extraordinary wave, the electric field of which is perpendicular to the magnetic field in plasma, in the transparency window at frequencies of 50-100 GHz. To avoid the effect of the density profile shape on the measurement results in the nonlinear mode of refractometer operation (near the cutoff), a system operating at two different probing frequencies was developed and tested. Such a system provides two values of the time delay, which can be used to estimate the peaking factor of the density distribution {alpha} and correctly determine the linear density Left-Pointing-Angle-Bracket Nl Right-Pointing-Angle-Bracket , regardless of the density profile (assuming a smooth density profile of the form of N({rho}) = N(0)(1 - {rho}{sup 2}){sup {alpha}}, where N(0) is the central plasma density and {rho} = r/a is the normalized plasma radius). The first experiments on density measurements in the FTU tokamak performed with this refractometer are described, and results from these experiments are presented. The formation of a thin dense plasma layer in the zone of a strong magnetic field (the so-called MARFE layer) at a relatively low (for FTU) plasma density of {approx}6 Multiplication-Sign 10{sup 19} m{sup -3} was detected. The thickness of this layer, determined from the refractometry data, agrees well with the data obtained using a digital camera.

  4. An investigation of Ar metastable state density in low pressure dual-frequency capacitively coupled argon and argon-diluted plasmas

    International Nuclear Information System (INIS)

    Liu, Wen-Yao; Xu, Yong; Peng, Fei; Guo, Qian; Li, Xiao-Song; Zhu, Ai-Min; Liu, Yong-Xin; Wang, You-Nian

    2015-01-01

    An tunable diode laser absorption spectroscopy has been used to determine the Ar*( 3 P 2 ) and Ar*( 3 P 0 ) metastable atoms densities in dual-frequency capacitively coupled plasmas. The effects of different control parameters, such as high-frequency power, gas pressure and content of Ar, on the densities of two metastable atoms and electron density were discussed in single-frequency and dual-frequency Ar discharges, respectively. Particularly, the effects of the pressure on the axial profile of the electron and Ar metastable state densities were also discussed. Furthermore, a simple rate model was employed and its results were compared with experiments to analyze the main production and loss processes of Ar metastable states. It is found that Ar metastable state is mainly produced by electron impact excitation from the ground state, and decayed by diffusion and collision quenching with electrons and neutral molecules. Besides, the addition of CF 4 was found to significantly increase the metastable destruction rate by the CF 4 quenching, especially for large CF 4 content and high pressure, it becomes the dominant depopulation process

  5. Low-frequency permittivity of spin-density wave in (TMTSF)2PF6 at low temperatures

    DEFF Research Database (Denmark)

    Nad, F.; Monceau, P.; Bechgaard, K.

    1995-01-01

    Conductivity and permittivity epsilon of(TMTSF)(2)PF6 have been measured at low frequencies of (10(2)-10(7) Hz) at low temperatures below the spin-density wave (SDW) transition temperature T-p. The temperature dependence of the conductivity shows a deviation from thermally activated behavior at T...

  6. ASPECTS OF DRIP IRRIGATION ON SLOPES

    Directory of Open Access Journals (Sweden)

    Oprea Radu

    2010-01-01

    Full Text Available Nowadays, water and its supply raise problems of strategic importance, of great complexity, being considered one of the keys to sustainable human development. Drip irrigation consists in the slow and controlled administration of water in the area of the root system of the plants for the purposes of fulfilling their physiological needs and is considered to be one of the variants of localized irrigation. Water is distributed in a uniform and slow manner, drop by drop, in a quantity and with a frequency that depend on the needs of the plant, thanks to the exact regulation of the water flow rate and pressure, as well as to the activation of the irrigation based on the information recorded by the tensiometer with regard to soil humidity. This method enables the exact dosage of the water quantity necessary in the various evolution stages of the plant, thus eliminating losses. By applying the irrigation with 5 liters of water per linear meter, at a 7 days interval, in the month of august, for a vine cultivated on a slope, in layers covered with black film and irrigated via dropping, soil humidity immediately after irrigation reaches its highest level, but within the limits of active humidity, on the line of the irrigation band. Three days later, the water content of the soil in the layer is relatively uniform, and, after this interval, it is higher in the points situated at the basis of the film. This technology of cultivation on slopes favors the accumulation, in the soil, of the water resulted from heavy rains and reduces soil losses as a result of erosion.

  7. Deep sea animal density and size estimated using a Dual-frequency IDentification SONar (DIDSON) offshore the island of Hawaii

    Science.gov (United States)

    Giorli, Giacomo; Drazen, Jeffrey C.; Neuheimer, Anna B.; Copeland, Adrienne; Au, Whitlow W. L.

    2018-01-01

    Pelagic animals that form deep sea scattering layers (DSLs) represent an important link in the food web between zooplankton and top predators. While estimating the composition, density and location of the DSL is important to understand mesopelagic ecosystem dynamics and to predict top predators' distribution, DSL composition and density are often estimated from trawls which may be biased in terms of extrusion, avoidance, and gear-associated biases. Instead, location and biomass of DSLs can be estimated from active acoustic techniques, though estimates are often in aggregate without regard to size or taxon specific information. For the first time in the open ocean, we used a DIDSON sonar to characterize the fauna in DSLs. Estimates of the numerical density and length of animals at different depths and locations along the Kona coast of the Island of Hawaii were determined. Data were collected below and inside the DSLs with the sonar mounted on a profiler. A total of 7068 animals were counted and sized. We estimated numerical densities ranging from 1 to 7 animals/m3 and individuals as long as 3 m were detected. These numerical densities were orders of magnitude higher than those estimated from trawls and average sizes of animals were much larger as well. A mixed model was used to characterize numerical density and length of animals as a function of deep sea layer sampled, location, time of day, and day of the year. Numerical density and length of animals varied by month, with numerical density also a function of depth. The DIDSON proved to be a good tool for open-ocean/deep-sea estimation of the numerical density and size of marine animals, especially larger ones. Further work is needed to understand how this methodology relates to estimates of volume backscatters obtained with standard echosounding techniques, density measures obtained with other sampling methodologies, and to precisely evaluate sampling biases.

  8. Effects of multi-frequency ultrasound pretreatment under low power density on the enzymolysis and the structure characterization of defatted wheat germ protein.

    Science.gov (United States)

    Yang, Xue; Li, Yunliang; Li, Suyun; Oladejo, Ayobami Olayemi; Wang, Yucheng; Huang, Shanfen; Zhou, Cunshan; Wang, Yang; Mao, Li; Zhang, Yanyan; Ma, Haile; Ye, Xiaofei

    2017-09-01

    The effects of ultrasonic frequency mode, power density, pretreatment time and other parameters under low power density on the degree of hydrolysis (DH) of defatted wheat germ protein (DWGP) and angiotensin-I-converting enzyme (ACE) inhibitory activity of DWGP hydrolysate were studied in this research. Ultraviolet-visible (UV-Vis) spectra, free sulfhydryl (SH), disulfide bond (SS), surface hydrophobicity and hydrophobic protein content of ultrasound-pretreated protein and hydrophobic amino acid (HAA) content of alcalase-hydrolysate of DWGP were measured under optimized ultrasonic condition. The ultrasonic frequency mode with dual-fixed frequency combination of 28/40kHz showed higher ACE inhibitory activity of DWGP hydrolysate compared with that of other ultrasound frequency modes and all the ultrasonic frequency combinations involving in 28kHz showed higher ACE inhibitory activity. Under the dual-fixed frequency ultrasound mode of 28/40kHz, ultrasonic power density of 60W/L, pretreatment time of 70min, temperature of 60°C and substrate concentration of 60g/L, the ACE inhibitory activity of DWGP hydrolysate was the highest with its value of 74.75% (increased by 62.30% compared to control). However, all the ultrasonic pretreatment did not increase the DH of DWGP significantly (p>0.05). The changes in UV-Vis spectra, SH and SS groups, surface hydrophobicity and hydrophobic protein content indicated that the structure of DWGP unfolded after ultrasound pretreatment. The HAA content of hydrolysate from the pretreated DWGP increased significantly (p<0.05). The results proved that ultrasound pretreatment loosed the protein structure and exposed more HAA residues of protein to be attacked easily by alcalase. This resulted in the increase in the HAA content which related to the ACE inhibitory activity. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Forecasting the density of oil futures returns using model-free implied volatility and high-frequency data

    International Nuclear Information System (INIS)

    Ielpo, Florian; Sevi, Benoit

    2013-09-01

    Forecasting the density of returns is useful for many purposes in finance, such as risk management activities, portfolio choice or derivative security pricing. Existing methods to forecast the density of returns either use prices of the asset of interest or option prices on this same asset. The latter method needs to convert the risk-neutral estimate of the density into a physical measure, which is computationally cumbersome. In this paper, we take the view of a practitioner who observes the implied volatility under the form of an index, namely the recent OVX, to forecast the density of oil futures returns for horizons going from 1 to 60 days. Using the recent methodology in Maheu and McCurdy (2011) to compute density predictions, we compare the performance of time series models using implied volatility and either daily or intra-daily futures prices. Our results indicate that models based on implied volatility deliver significantly better density forecasts at all horizons, which is in line with numerous studies delivering the same evidence for volatility point forecast. (authors)

  10. Drip irrigation using a PLC based adaptive irrigation system

    OpenAIRE

    Shahidian, S.; Serralheiro, R. P.; Teixeira, J. L.; Santos, F. L.; Oliveira, M. R. G.; Costa, J. L.; Toureiro, C.; Haie, Naim; Machado, R. M.

    2009-01-01

    Most of the water used by man goes to irrigation. A major part of this water is used to irrigate small plots where it is not feasible to implement full-scale Evapotranspiration based irrigation controllers. During the growth season crop water needs do not remain constant and varies depending on the canopy, growth stage and climate conditions such as temperature, wind, relative humidity and solar radiation. Thus, it is necessary to find an economic irrigation controller that can adapt the dail...

  11. Bone Mineral Density and Food-frequency in Korean Adults: The 2008 and 2009 Korea National Health and Nutrition Examination Survey.

    Science.gov (United States)

    Yoon, Eui-Hyun; Noh, Hyoung; Lee, Hyang-Mee; Hwang, Hwan-Sik; Park, Hoon-Ki; Park, Yong-Soon

    2012-09-01

    Diet and Nutrition are important modulators of bone health in men and women. We investigated the associations between frequency of food intake among certain food groups and bone mineral density (BMD) in a large population of Korean adults. We used the data from Korea National Health and Nutrition Examination Survey during 2008 to 2009. Participants were aged 20 years and over. BMDs were measured at lumbar spine and femoral neck with dual-energy X-ray absorptiometry. Dietary and supplement intakes were assessed by food-frequency questionnaire. We used multiple linear regression analysis to evaluate the relationships between annual food-frequency of each food group and BMD. After adjustment of multiple covariates, femoral neck and lumbar BMD significantly increased as the frequency of fruit consumption increased in both men and women. Frequency of other carbohydrates consumption was significantly associated with greater femoral neck and lumbar BMD for women. Frequency of milk and dairy product consumption was significantly associated with greater femoral neck BMD in men. Other food groups, however, had no significant associations with BMDs. Frequent consumption of fruit has a positive association with BMDs in men and women. Milk and dairy products and other carbohydrates also had positive effects on BMD for men and women, respectively.

  12. On the secular decrease of radio emission flux densities of the supernova remnants of Cassiopeia A and Taurus A at frequency 927 MHz

    International Nuclear Information System (INIS)

    Vinyajkin, E.N.; Razin, V.A.

    1979-01-01

    Relative measurements of the radio emission flux densities of the supernova remnants of Cassiopeia A and Taurus A were made at the frequency 927 MHz to investigate the secular decrease of their intensity. Experiments were fulfilled in October-December 1977 at the 10-meter radio telescope of the radioastronomical station Staraya Pustyn' (NIRFI). The radio galaxied of Cygnus A, Virgo A and Orion Nebula were taken as the comparison sources. The comparison of the data obtained with the results of absolute measurements carried out in October 1962 permits to state that during 15 years the radio emission flux density of Cassiopeia A decreased by (14.2+-0.6)% (the average annual decrease amounts to (0.95+-O.04)%) and the radio emission flux density of Taurus A decreased by (2.7+-0.1)% (the annual decrease is (0.18+-0.01)%)

  13. Cell density dependence of transformation frequencies in C3H10T1/2 cells exposed to X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Bettega, D; Calzolari, P; Ottolenghi, A; Lombardi, L T [Milan Univ. (Italy). Ist. di Fisica; Rimoldi, E [Milan Univ. (Italy). Ist. di Radiologia Veterinaria

    1989-12-01

    The effects of cell density on transformation frequencies were studied in C3H10T1/2 cells exposed to 0.5 and 7 Gy of 200 kVp X-rays. Initial cell density strongly influenced transformation frequency; this decreased by a factor of between 4 and 10 when the initial seeding density was changed from 50 to 2500 cells/10 cm diameter Petri dish. The data were fitted with two equations: (a) an allometric function represented on a log-log scale by a straight line and (b) a sigmoidal function with plateaux between 50 and 250 cells/dish and above 600. The two curves are compared and their probabilities discussed. Our data indicate that the region between 50 and 250 cells/dish would be the most suitable region for dose-effect measurements. A study of the growth curves at 0.5 and 8.5 Gy shows that cell growth rates are not influenced by initial cell density. (author).

  14. Molecular structures and vibrational frequencies of xanthine and its methyl derivatives (caffeine and theobromine) by ab initio Hartree-Fock and density functional theory calculations

    Science.gov (United States)

    Ucun, Fatih; Sağlam, Adnan; Güçlü, Vesile

    2007-06-01

    The molecular structures, vibrational frequencies and corresponding vibrational assignments of xanthine and its methyl derivatives (caffeine and theobromine) have been calculated using ab initio Hartree-Fock (HF) and density functional theory (B3LYP) methods with 6-31G(d, p) basis set level. The calculations were utilized to the CS symmetries of the molecules. The obtained vibrational frequencies and optimised geometric parameters (bond lengths and bond angles) were seen to be well agreement with the experimental data. The used scale factors which have been obtained the ratio of the frequency values of the strongest peaks in the calculated and experimental spectra seem to cause the gained vibrations well corresponding to the experimental ones. Theoretical infrared intensities and Raman activities are also reported.

  15. Clinical value of colonic irrigation in patients with continence disturbances.

    Science.gov (United States)

    Briel, J W; Schouten, W R; Vlot, E A; Smits, S; van Kessel, I

    1997-07-01

    Continence disturbances, especially fecal soiling, are difficult to treat. Irrigation of the distal part of the large bowel might be considered as a nonsurgical alternative for patients with impaired continence. This study is aimed at evaluating the clinical value of colonic irrigation. Thirty-two patients (16 females; median age, 47 (range, 23-72) years) were offered colonic irrigation on an ambulatory basis. Sixteen patients suffered from fecal soiling (Group I), whereas the other 16 patients were treated for fecal incontinence (Group II). Patients were instructed by enterostomal therapists how to use a conventional colostomy irrigation set to obtain sufficient irrigation of the distal part of their large bowel. Patients with continence disturbances during the daytime were instructed to introduce 500 to 1,000 ml of warm (38 degrees C) water within 5 to 10 minutes after they passed their first stool. In addition, they were advised to wait until the urge to defecate was felt. Patients with soiling during overnight sleep were advised to irrigate during the evening. To determine clinical outcome, a detailed questionnaire was used. Median duration of follow-up was 18 months. Ten patients discontinued irrigation within the first month of treatment. Symptoms resolved completely in two patients. They believed that there was no need to continue treatment any longer. Irrigation had no effect in two patients. Despite the fact that symptoms resolved, six patients discontinued treatment because they experienced pain (n = 2) or they considered the irrigation to be too time-consuming (n = 4). Twenty-two patients are still performing irrigations. Most patients irrigated the colon in the morning after the first stool was passed. Time needed for washout varied between 10 and 90 minutes. Frequency of irrigations varied from two times per day to two times per week. In Group I, irrigation was found to be beneficial in 92 percent of patients, whereas 60 percent of patients in Group II

  16. An assessment of colostomy irrigation.

    Science.gov (United States)

    Laucks, S S; Mazier, W P; Milsom, J W; Buffin, S E; Anderson, J M; Warwick, M K; Surrell, J A

    1988-04-01

    One hundred patients with permanent sigmoid colostomies were surveyed to determine their satisfaction and success with the "irrigation" technique of colostomy management. Most patients who irrigate their colostomies achieve continence. Odors and skin irritation are minimized. The irrigation method is economical, time efficient, and allows a reasonably liberal diet. It avoids bulky appliances and is safe. In appropriately selected patients, the irrigation technique is the method of choice for management of an end-sigmoid colostomy.

  17. Determining the von Mises stress power spectral density for frequency domain fatigue analysis including out-of-phase stress components

    NARCIS (Netherlands)

    Bonte, M.H.A.; de Boer, Andries; Liebregts, R.

    This paper provides a new formula to take into account phase differences in the determination of an equivalent von Mises stress power spectral density (PSD) from multiple random inputs. The obtained von Mises PSD can subsequently be used for fatigue analysis. The formula was derived for use in the

  18. The Precise Time Course of Lexical Activation: MEG Measurements of the Effects of Frequency, Probability, and Density in Lexical Decision

    Science.gov (United States)

    Stockall, Linnaea; Stringfellow, Andrew; Marantz, Alec

    2004-01-01

    Visually presented letter strings consistently yield three MEG response components: the M170, associated with letter-string processing (Tarkiainen, Helenius, Hansen, Cornelissen, & Salmelin, 1999); the M250, affected by phonotactic probability, (Pylkkanen, Stringfellow, & Marantz, 2002); and the M350, responsive to lexical frequency (Embick,…

  19. Unsaturated flow dynamics during irrigation with wastewater: field and modelling study

    Science.gov (United States)

    Martinez-Hernandez, V.; de Miguel, A.; Meffe, R.; Leal, M.; González-Naranjo, V.; de Bustamante, I.

    2012-04-01

    To deal with water scarcity combined with a growing water demand, the reuse of wastewater effluents of wastewater treatment plants (WWTP) for industrial and agricultural purposes is considered as a technically and economically feasible solution. In agriculture, irrigation with wastewater emerges as a sustainable practice that should be considered in such scenarios. Water infiltration, soil moisture storage and evapotranspiration occurring in the unsaturated zone are fundamental processes that play an important role in soil water balance. An accurate estimation of unsaturated flow dynamics (during and after irrigation) is essential to improve wastewater management (i.e. estimating groundwater recharge or maximizing irrigation efficiency) and to avoid possible soil and groundwater affections (i.e. predicting contaminant transport). The study site is located in the Experimental Plant of Carrión de los Céspedes (Seville, Spain). Here, treated wastewater is irrigated over the soil to enhance plants growth. To obtain physical characteristics of the soil (granulometry, bulk density and water retention curve), soil samples were collected at different depths. A drain gauge passive capillary lysimeter was installed to determine the volume of water draining from the vadose zone. Volumetric water content of the soil was monitored by measuring the dielectric constant using capacitance/frequency domain technology. Three soil moisture probes were located at different depths (20, 50 and 70 cm below the ground surface) to control the variation of the volumetric water content during infiltration. The main aim of this study is to understand water flow dynamics through the unsaturated zone during irrigation by using the finite element model Hydrus-1D. The experimental conditions were simulated by a 90 cm long, one dimensional solution domain. Specific climatic conditions, wastewater irrigation rates and physical properties of the soil were introduced in the model as input parameters

  20. Evaluating two irrigation controllers under subsurface drip irrigated tomato crop

    International Nuclear Information System (INIS)

    Al-Ghobari, H.M.; Mohammad, F.S.; El Marazky, M.S.A.

    2016-01-01

    Smart systems could be used to improve irrigation scheduling and save water under Saudi Arabia’s present water crisis scenario. This study investigated two types of evapotranspiration-based smart irrigation controllers, SmartLine and Hunter Pro-C2, as promising tools for scheduling irrigation and quantifying plants’ water requirements to achieve water savings. The effectiveness of these technologies in reducing the amount of irrigation water was compared with the conventional irrigation scheduling method as a control treatment. The two smart irrigation sensors were used for subsurface irrigation of a tomato crop (cv. Nema) in an arid region. The results showed that the smart controllers significantly reduced the amount of applied water and increased the crop yield. In general, the Hunter Pro-C2 system saved the highest amount of water and produced the highest crop yield, resulting in the highest water irrigation efficiency compared with the SmartLine controller and the traditional irrigation schedule. It can be concluded that the application of advanced scheduling irrigation techniques such as the Hunter controller under arid conditions can realise economic benefits by saving large amounts of irrigation water.

  1. Evaluating two irrigation controllers under subsurface drip irrigated tomato crop

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ghobari, H.M.; Mohammad, F.S.; El Marazky, M.S.A.

    2016-07-01

    Smart systems could be used to improve irrigation scheduling and save water under Saudi Arabia’s present water crisis scenario. This study investigated two types of evapotranspiration-based smart irrigation controllers, SmartLine and Hunter Pro-C2, as promising tools for scheduling irrigation and quantifying plants’ water requirements to achieve water savings. The effectiveness of these technologies in reducing the amount of irrigation water was compared with the conventional irrigation scheduling method as a control treatment. The two smart irrigation sensors were used for subsurface irrigation of a tomato crop (cv. Nema) in an arid region. The results showed that the smart controllers significantly reduced the amount of applied water and increased the crop yield. In general, the Hunter Pro-C2 system saved the highest amount of water and produced the highest crop yield, resulting in the highest water irrigation efficiency compared with the SmartLine controller and the traditional irrigation schedule. It can be concluded that the application of advanced scheduling irrigation techniques such as the Hunter controller under arid conditions can realise economic benefits by saving large amounts of irrigation water.

  2. Optimization of hydrostatic pressure at varied sonication conditions--power density, intensity, very low frequency--for isothermal ultrasonic sludge treatment.

    Science.gov (United States)

    Delmas, Henri; Le, Ngoc Tuan; Barthe, Laurie; Julcour-Lebigue, Carine

    2015-07-01

    This work aims at investigating for the first time the key sonication (US) parameters: power density (DUS), intensity (IUS), and frequency (FS) - down to audible range, under varied hydrostatic pressure (Ph) and low temperature isothermal conditions (to avoid any thermal effect). The selected application was activated sludge disintegration, a major industrial US process. For a rational approach all comparisons were made at same specific energy input (ES, US energy per solid weight) which is also the relevant economic criterion. The decoupling of power density and intensity was obtained by either changing the sludge volume or most often by changing probe diameter, all other characteristics being unchanged. Comprehensive results were obtained by varying the hydrostatic pressure at given power density and intensity. In all cases marked maxima of sludge disintegration appeared at optimum pressures, which values increased at increasing power intensity and density. Such optimum was expected due to opposite effects of increasing hydrostatic pressure: higher cavitation threshold then smaller and fewer bubbles, but higher temperature and pressure at the end of collapse. In addition the first attempt to lower US frequency down to audible range was very successful: at any operation condition (DUS, IUS, Ph, sludge concentration and type) higher sludge disintegration was obtained at 12 kHz than at 20 kHz. The same values of optimum pressure were observed at 12 and 20 kHz. At same energy consumption the best conditions - obtained at 12 kHz, maximum power density 720 W/L and 3.25 bar - provided about 100% improvement with respect to usual conditions (1 bar, 20 kHz). Important energy savings and equipment size reduction may then be expected. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Frequency domain Monte Carlo simulation method for cross power spectral density driven by periodically pulsed spallation neutron source using complex-valued weight Monte Carlo

    International Nuclear Information System (INIS)

    Yamamoto, Toshihiro

    2014-01-01

    Highlights: • The cross power spectral density in ADS has correlated and uncorrelated components. • A frequency domain Monte Carlo method to calculate the uncorrelated one is developed. • The method solves the Fourier transformed transport equation. • The method uses complex-valued weights to solve the equation. • The new method reproduces well the CPSDs calculated with time domain MC method. - Abstract: In an accelerator driven system (ADS), pulsed spallation neutrons are injected at a constant frequency. The cross power spectral density (CPSD), which can be used for monitoring the subcriticality of the ADS, is composed of the correlated and uncorrelated components. The uncorrelated component is described by a series of the Dirac delta functions that occur at the integer multiples of the pulse repetition frequency. In the present paper, a Monte Carlo method to solve the Fourier transformed neutron transport equation with a periodically pulsed neutron source term has been developed to obtain the CPSD in ADSs. Since the Fourier transformed flux is a complex-valued quantity, the Monte Carlo method introduces complex-valued weights to solve the Fourier transformed equation. The Monte Carlo algorithm used in this paper is similar to the one that was developed by the author of this paper to calculate the neutron noise caused by cross section perturbations. The newly-developed Monte Carlo algorithm is benchmarked to the conventional time domain Monte Carlo simulation technique. The CPSDs are obtained both with the newly-developed frequency domain Monte Carlo method and the conventional time domain Monte Carlo method for a one-dimensional infinite slab. The CPSDs obtained with the frequency domain Monte Carlo method agree well with those with the time domain method. The higher order mode effects on the CPSD in an ADS with a periodically pulsed neutron source are discussed

  4. Evaluation of the Effect of Different Irrigation Levels of Drip Irrigation (Tape on Yield and Yield Components of Corn

    Directory of Open Access Journals (Sweden)

    mohammad karimi

    2016-02-01

    Full Text Available Introduction: One of the serious problems in the further development of maize cultivation is increasing irrigation efficiency. Using conventional irrigation causes a shortage of water resources to increase the acreage of the crop. With regard to the development of maize cultivation, agronomic and executable methods must be studied to reduce water consumption. Using drip irrigation system is most suitable for row crops. Hamedi et al. (2005 compared drip (tape and surface irrigation systems on yield of maize in different levels of water requirement and indicated that drip irrigation increases the amount of yield to 2015 kg/ha and water use efficiency to 3 time. Kohi et al. (2005 investigated the effects of deficit irrigation use of drip (tape irrigation on water use efficiency on maize in planting of one and two rows. The results showed that maximum water use efficiency related to crop density, water requirement and planting pattern 85000, 125% and two rows, respectively with 1.46 kg/m3. Jafari and Ashrafi (2011 studied the effects of irrigation levels, plant density and planting pattern in drip irrigation (tape on corn. The results showed that the amount of irrigation water and crop density on the level of 1% and their interactions and method of planting were significant at the 5 and 10% on water use efficiency, respectively. The yield was measured under different levels of irrigation, crop density and method of planting and the difference was significant on the level of 1%. Lamm et al. (1995 studied water requirement of maize in field with silt loam texture under sub drip irrigation and reported that water use reduced to 75%; but yield of maize remained at maximum amount of 12.5 t/ha. The objective of this study was to evaluate the drip (tape irrigation method for corn production practices in the Qazvin province in Iran. Materials and Methods: In this study, yield and yield components of corn (SC 704 were investigated under different levels of

  5. Sensitivity of coronal loop sausage mode frequencies and decay rates to radial and longitudinal density inhomogeneities: a spectral approach

    Science.gov (United States)

    Cally, Paul S.; Xiong, Ming

    2018-01-01

    Fast sausage modes in solar magnetic coronal loops are only fully contained in unrealistically short dense loops. Otherwise they are leaky, losing energy to their surrounds as outgoing waves. This causes any oscillation to decay exponentially in time. Simultaneous observations of both period and decay rate therefore reveal the eigenfrequency of the observed mode, and potentially insight into the tubes’ nonuniform internal structure. In this article, a global spectral description of the oscillations is presented that results in an implicit matrix eigenvalue equation where the eigenvalues are associated predominantly with the diagonal terms of the matrix. The off-diagonal terms vanish identically if the tube is uniform. A linearized perturbation approach, applied with respect to a uniform reference model, is developed that makes the eigenvalues explicit. The implicit eigenvalue problem is easily solved numerically though, and it is shown that knowledge of the real and imaginary parts of the eigenfrequency is sufficient to determine the width and density contrast of a boundary layer over which the tubes’ enhanced internal densities drop to ambient values. Linearized density kernels are developed that show sensitivity only to the extreme outside of the loops for radial fundamental modes, especially for small density enhancements, with no sensitivity to the core. Higher radial harmonics do show some internal sensitivity, but these will be more difficult to observe. Only kink modes are sensitive to the tube centres. Variation in internal and external Alfvén speed along the loop is shown to have little effect on the fundamental dimensionless eigenfrequency, though the associated eigenfunction becomes more compact at the loop apex as stratification increases, or may even displace from the apex.

  6. Crescimento inicial de duas cultivares de cafeeiro adensado influenciado por níveis de irrigação localizada Initial growth of two high-density coffee tree cultivars influenced by drip irrigation levels

    Directory of Open Access Journals (Sweden)

    Márcio S. Santana

    2004-12-01

    Full Text Available O experimento foi conduzido na Fazenda Água Limpa, Universidade de Brasília, tendo como objetivo avaliar o crescimento das cultivares de café IAPAR-59 e Obatã, submetidas a cinco níveis de irrigação por gotejamento durante o primeiro ano de formação e estudar formas de manejo da água do solo. O delineamento experimental usado foi o de blocos completos ao acaso para o fator irrigação em parcelas, com o fator cultivar em subparcela e o fator tempo em dias após o transplante (dat em subsubparcela, com seis repetições. Os cinco níveis de irrigação foram tensões de 20; 40 e 60 kPa determinadas com o auxílio de tensiômetros, sistema Irrigas com tensão definida pelo próprio sensor e sem irrigação. As variáveis de crescimento avaliadas foram índice de área foliar, número de folhas, diâmetro do caule, altura de plantas e número de ramos plagiotrópicos. Aos 316 dat, os tratamentos irrigados tiveram o mesmo comportamento de crescimento, mas foram significativamente maiores em relação ao tratamento não irrigado. O sistema Irrigas mostrou ser uma opção para o manejo adequado da água com manutenção nula. As cultivares IAPAR-59 e Obatã têm comportamento de crescimento diferenciado, com todas as variáveis avaliadas favorecendo esta última.The experiment was carried out at "Água Limpa" Farm, University of Brasilia. The objective was to evaluate growth of IAPAR-59 and Obatã cultivars using five drip irrigation levels, during the crop of the first year and to study soil water management. It was used a randomized complete block design for the irrigation factor, with the cultivar factor as a split plot on irrigation and the factor time in days after transplanting (dat as a split plot on cultivar. The five irrigation levels were 20; 40 and 60 kPa, established using tensiometers; Irrigas system with soil water tension defined by its sensor; and no irrigation. Growth variables evaluated were leaf area index, leaf number

  7. Effect of different irrigation systems on root growth of maize and cowpea plants in sandy soil

    Directory of Open Access Journals (Sweden)

    Noha A. Mahgoub

    2017-10-01

    Full Text Available A field experiment was conducted at the Experimental Farm, Faculty of Agriculture, Suez Canal University to study the influence of different irrigation systems on root length density and specific root length of maize and cowpea plants cultivated in sandy soil. Three irrigation systems (Surface, drip and sprinkler irrigation were used in this study. The NPK fertilizers were applied as recommended doses for maize and cowpea. Root samples were collected from the soil profile below one plant (maize and cowpea which was irrigated by the three irrigation systems by using an iron box (30 cm× 20 cm which is divided into 24 small boxes each box is (5× 5 × 5 cm. At surface irrigation, root length density of cowpea reached to soil depth 30-40cm with lateral distances 5-10 cm and 15-20 cm. Vertical distribution of root length density of maize was increased with soil depth till 20-25 cm, and then it decreased till soil depth 35-40cm. Under drip irrigation, root length density of cowpea increased horizontally from 0-5cm to 10-15cm then it decreased till soil depth 25-30 cm and below this depth root length density disappeared. For the root length density and specific root length of maize under drip irrigation, the data showed that root length density and specific root length decreased with increasing in soil depth. The root length density of cowpea under sprinkler irrigation at 0-5cm disappeared from horizontal distance at 25-30 cm. The data showed that root length density of maize under sprinkler irrigation was higher at the soil top layers 0-5 cm and 5-10 cm than other layers from 10-40 cm.

  8. Effects of density functionals and dispersion interactions on geometries, bond energies and harmonic frequencies of Etbnd UX3 (E = N, P, CH; X = H, F, Cl)

    Science.gov (United States)

    Pandey, Krishna Kumar; Patidar, Pankaj; Patidar, Sunil Kumar; Vishwakarma, Ravi

    2014-12-01

    Quantum-chemical calculations have been performed to evaluate the geometries, bonding nature and harmonic frequencies of the compounds [Etbnd UX3] at DFT, DFT-D3, DFT-D3(BJ) and DFT-dDSc levels using different density functionals BP86, BLYP, PBE, revPBE, PW91, TPSS and M06-L. The stretching frequency of Utbnd N bond in [Ntbnd UF3] calculated with DFT/BLYP closely resembles with the experimental value. The performance of different density functionals for accurate Utbnd N vibrational frequencies follows the order BLYP > revPBE > BP86 > PW91 > TPSS > PBE > M06-L. The BLYP functional gives accurate value of the Utbnd E bond distances. The uranium atom in the studied compounds [Etbnd UX3] is positively charged. Upon going from [Etbnd UF3] to [Etbnd UCl3], the partial Hirshfeld charge on uranium atom decreases because of the lower electronegativity of chlorine compared to flourine. The Gopinathan-Jug bond order for Utbnd E bonds ranges from 2.90 to 3.29. The Utbnd E bond dissociation energies vary with different density functionals as M06-L < TPSS < BLYP < revPBE < BP86 < PBE ≈ PW91. The orbital interactions ΔEorb, in all studied compounds [Etbnd UX3] are larger than the electrostatic interaction ΔEelstat, which means the Utbnd N bonds in these compound have greater degree of covalent character (in the range 63.8-77.2%). The Usbnd E σ-bonding interaction is the dominant bonding interaction in the nitride and methylidyne complexes while it is weaker in [Ptbnd UX3]. The dispersion energy contributions to the total bond dissociation energies are rather small. Compared to the Grimme's D3(BJ) corrections, the Corminboeuf's dispersion corrections are larger with metaGGA functionals (TPSS, M06-L) while smaller with GGA functionals.

  9. Optimized Subsurface Irrigation System: The Future of Sugarcane Irrigation

    Directory of Open Access Journals (Sweden)

    M. H. J. P. Gunarathna

    2018-03-01

    Full Text Available Climate change may harm the growth and yield of sugarcane (Saccharum officinarum L. without the introduction of appropriate irrigation facilities. Therefore, new irrigation methods should be developed to maximize water use efficiency and reduce operational costs. OPSIS (optimized subsurface irrigation system is a new solar-powered automatic subsurface irrigation system that creates a phreatic zone below crop roots and relies on capillarity to supply water to the root zone. It is designed for upland crops such as sugarcane. We investigated the performance of OPSIS for irrigating sugarcane and evaluated its performance against sprinkler irrigation under subtropical conditions. We conducted field experiments in Okinawa, Japan, over the period from 2013 to 2016 and took measurements during spring- and summer-planted main crops and two ratoon crops of the spring-planted crop. Compared with sprinkler irrigation, OPSIS produced a significantly higher fresh cane yield, consumed less irrigation water and provided a higher irrigation water use efficiency. We conclude that OPSIS could be adopted as a sustainable solution to sugarcane irrigation in Okinawa and similar environments.

  10. Characteristics of short distance field of a source radiating at electronic frequencies in a ionospheric plasma. Applications to density and electron temperature measurement by mutual impedance probe

    International Nuclear Information System (INIS)

    Debrie, R.

    1983-06-01

    Realization of a new type of radio-frequency probe, the mutual-impedance probe (or the quadrupole probe) is developed. Theoretical results obtained with a cold plasma description of the ionized medium with static magnetic field. Transfer impedance between two dipoles in an homogeneous hot and isotope plasma is then calculated. In equatorial ionosphere, measurements made by the H.F. quadrupole probe, in the Veronique rocket, during the Cisaspe experiment, have been interpreted with this hot plasma theory. The influence of a plasma drift with respect to the emitter dipole is analyzed. The influence of a static magnetic field in hot and homogeneous plasma, on the frequency response curve of the mutual impedance is studied. For, in ionospheric plasmas of auroral and polar zones, the earth magnetic field is no more negligible and gives to the plasma dielectric, strongly anisotropic, properties well described by the microscopic theory in hot magnetoplasma. The space time fast evolution of characteristics of plasma encountered in space experiments has been shown up with a new method of measurement the self-oscillating quadrupole probe. The work synthesis is put in a concrete form on the polar satellite Aureol-3 the first results of which are presented. This satellite allows a precise study of ionosphere auroral zones. At last, it is shown that methods developed for electron density and temperature measurements can be transposed in low frequency. In this case, measurements with quadrupole probe allow to get the ion average mass by lower hybrid frequency excitation [fr

  11. Effects of power densities, continuous and pulse frequencies, and number of sessions of low-level laser therapy on intact rat brain.

    Science.gov (United States)

    Ilic, Sanja; Leichliter, Sandra; Streeter, Jackson; Oron, Amir; DeTaboada, Luis; Oron, Uri

    2006-08-01

    The aim of the present study was to investigate the possible short- and long-term adverse neurological effects of low-level laser therapy (LLLT) given at different power densities, frequencies, and modalities on the intact rat brain. LLLT has been shown to modulate biological processes depending on power density, wavelength, and frequency. To date, few well-controlled safety studies on LLLT are available. One hundred and eighteen rats were used in the study. Diode laser (808 nm, wavelength) was used to deliver power densities of 7.5, 75, and 750 mW/cm2 transcranially to the brain cortex of mature rats, in either continuous wave (CW) or pulse (Pu) modes. Multiple doses of 7.5 mW/cm2 were also applied. Standard neurological examination of the rats was performed during the follow-up periods after laser irradiation. Histology was performed at light and electron microscopy levels. Both the scores from standard neurological tests and the histopathological examination indicated that there was no long-term difference between laser-treated and control groups up to 70 days post-treatment. The only rats showing an adverse neurological effect were those in the 750 mW/cm2 (about 100-fold optimal dose), CW mode group. In Pu mode, there was much less heating, and no tissue damage was noted. Long-term safety tests lasting 30 and 70 days at optimal 10x and 100x doses, as well as at multiple doses at the same power densities, indicate that the tested laser energy doses are safe under this treatment regime. Neurological deficits and histopathological damage to 750 mW/cm2 CW laser irradiation are attributed to thermal damage and not due to tissue-photon interactions.

  12. Portable photovoltaic irrigation pumps

    Energy Technology Data Exchange (ETDEWEB)

    Furber, J. D.

    1980-07-01

    Experiences in developing a solar-powered irrigation pump to meet the needs of poor farmers in developing nations are summarized. The design which evolved is small and portable, employing a high-efficiency electric pump, powered by photovoltaic panels. Particular emphasis is placed on how the system works, and on early field problems experienced with the first prototypes. The resolution of these problems and the performance of actual systems in various countries is presented and user responses are noted.

  13. Indium--tin oxide films radio frequency sputtered from specially formulated high density indium--tin oxide targets

    International Nuclear Information System (INIS)

    Kulkarni, S.; Bayard, M.

    1991-01-01

    High density ITO (indium--tin oxide) targets doped with Al 2 O 3 and SiO 2 manufactured in the Tektronix Ceramics Division have been used to rf sputter ITO films of various thicknesses on borosilicate glass substrates. Sputtering in an oxygen--argon gas mixture and annealing in forming gas, resulted in ITO films exhibiting 90% transmission at 550 nm and a sheet resistance of 15 Ω/sq for a thickness of 1100 A. Sputtering in an oxygen--argon gas mixture and annealing in air increased sheet resistance without a large effect on the transmission. Films sputtered in argon gas alone were transparent in the visible and the sheet resistance was found to be 100--180 Ω/sq for the same thickness, without annealing

  14. [Irrigation in colostomies].

    Science.gov (United States)

    Campo, Juana; Lecona, Ana; Caparrós, M Rosario; Barbero, M Antonia; Javier Cerdán, F

    2002-01-01

    The degree of acceptation of irrigation from a colostomy varies ostensibly from some cases to others, therefore, we study what occurs in our medium, separating those patients which have previously undergone other procedures (Group A) from those patients who have been informed and trained about the immediate postoperative period (Group B). 48 patients, 22 or 46% of these patients were considered not apt for irrigation. Of the 26 to whom this procedure was proposed, 14 or 54% accepted. Of these, 5 or 36% abandoned its use while 9 continued its use; this is 64% of those who accepted this procedure, 35% of those to whom it was proposed and 19% of the total study group. 189 patients. This procedure was not recommended to 95 patients, 50%. Of the 94 patients to whom this procedure was proposed, 65 or 69% accepted. Of these, 22 or 34% abandoned its use while 43 continued its use; this is 66% of those; who accepted this procedure, 46% of those to whom it was proposed and 23% of the total study group. In our medium, the practice of irrigation oscillates between 19 and 23% of patients who have undergone a colostomy, without any significant difference referring to the moment when a patient started this procedure. A first report on this study was submitted in the III National Congress for Nursing in Colostomies.

  15. ROOT CANAL IRRIGANTS AND IRRIGATION TECHNIQUES: A REVIEW

    OpenAIRE

    Aniketh; Mohamed; Geeta; Nandakishore; Gourav Kumar; Patrick Timothy; Jayson Mathew; Sahle Abdul

    2015-01-01

    Root canal irrigation is not much emphasised in endodontic therapy. Most articles discussed are on root canal shaping and obturation not much emphasis is given for irrigation. There are many irrigation solutions which are introduced into market. The primary objective of root canal therapy is the ret ention of the pulpless or pulpally involved tooth with its associated periapical tissues in a healthy state. Achievement of this objective requires that the pulpal spaces and con...

  16. Range-separated time-dependent density-functional theory with a frequency-dependent second-order Bethe-Salpeter correlation kernel

    Energy Technology Data Exchange (ETDEWEB)

    Rebolini, Elisa, E-mail: elisa.rebolini@kjemi.uio.no; Toulouse, Julien, E-mail: julien.toulouse@upmc.fr [Laboratoire de Chimie Théorique, Sorbonne Universités, UPMC Univ Paris 06, CNRS, 4 place Jussieu, F-75005 Paris (France)

    2016-03-07

    We present a range-separated linear-response time-dependent density-functional theory (TDDFT) which combines a density-functional approximation for the short-range response kernel and a frequency-dependent second-order Bethe-Salpeter approximation for the long-range response kernel. This approach goes beyond the adiabatic approximation usually used in linear-response TDDFT and aims at improving the accuracy of calculations of electronic excitation energies of molecular systems. A detailed derivation of the frequency-dependent second-order Bethe-Salpeter correlation kernel is given using many-body Green-function theory. Preliminary tests of this range-separated TDDFT method are presented for the calculation of excitation energies of the He and Be atoms and small molecules (H{sub 2}, N{sub 2}, CO{sub 2}, H{sub 2}CO, and C{sub 2}H{sub 4}). The results suggest that the addition of the long-range second-order Bethe-Salpeter correlation kernel overall slightly improves the excitation energies.

  17. Temporal evolution of electron density in a low pressure pulsed two-frequency (60 MHz/2 MHz) capacitively coupled plasma discharge

    International Nuclear Information System (INIS)

    Sirse, N; Ellingboe, A R; Jeon, M H; Yeom, G Y

    2014-01-01

    Time-resolved electron density, n e , is measured in a low pressure pulsed two-frequency capacitively coupled plasma discharge sustained in Ar and in Ar/CF 4 /O 2 (80 : 10 : 10) gas mixture using a floating resonance hairpin probe. The top electrode is powered by 60 MHz in pulse mode and the bottom electrode is powered by 2 MHz in continuous wave mode. The dependence of time-resolved n e on the low frequency (LF) and high frequency (HF) power levels, operating gas pressure, pulse repetition frequency (PRF) and duty cycle are investigated. It is found that the steady state n e in the long on-phase is greatly influenced by the HF power level and slightly affected by the LF power level in both Ar and Ar/CF 4 /O 2 plasma. The decay time of n e is slow (∼30–90 µs) in the case of Ar plasma and strongly depends on the LF power level, whereas in the case of Ar/CF 4 /O 2 gas mixture it is very fast (∼15 µs) and marginally dependent on LF power level. In Ar plasma the steady state n e is increasing with a rise in operating gas pressure, however, in Ar/CF 4 /O 2 plasma it first increases with gas pressure reaching to the maximum (at 20 mTorr) value and then decreases. The pressure dependence of decay time constant mimics the pressure variation of steady state n e . Furthermore, it is observed that the on-phase electron density is greatly affected by changing the PRF and duty cycle. This effect is more prominent in Ar/CF 4 /O 2 plasma when compared to Ar discharge. In addition, n e is observed to overshoot the steady state densities in the beginning of the on-phase in Ar/CF 4 /O 2 gas mixture, but this effect is either small or absent in the case of Ar plasma. (paper)

  18. Making the user visible: analysing irrigation practices and farmers’ logic to explain actual drip irrigation performance

    NARCIS (Netherlands)

    Benouniche, M.; Kuper, M.; Hammani, A.; Boesveld, H.

    2014-01-01

    The actual performance of drip irrigation (irrigation efficiency, distribution uniformity) in the field is often quite different from that obtained in experimental stations. We developed an approach to explain the actual irrigation performance of drip irrigation systems by linking measured

  19. Electron density window for best frequency performance, lowest phase noise and slowest degradation of GaN heterostructure field-effect transistors

    International Nuclear Information System (INIS)

    Matulionis, Arvydas

    2013-01-01

    The problems in the realm of nitride heterostructure field-effect transistors (HFETs) are discussed in terms of a novel fluctuation–dissipation-based approach impelled by a recent demonstration of strong correlation of hot-electron fluctuations with frequency performance and degradation of the devices. The correlation has its genesis in the dissipation of the LO-mode heat accumulated by the non-equilibrium longitudinal optical phonons (hot phonons) confined in the channel that hosts the high-density hot-electron gas subjected to a high electric field. The LO-mode heat causes additional scattering of hot electrons and facilitates defect formation in a different manner than the conventional heat contained mainly in the acoustic phonon mode. We treat the heat dissipation problem in terms of the hot-phonon lifetime responsible for the conversion of the non-migrant hot phonons into migrant acoustic modes and other vibrations. The lifetime is measured over a wide range of electron density and supplied electric power. The optimal conditions for the dissipation of the LO-mode heat are associated with the plasmon-assisted disintegration of hot phonons. Signatures of plasmons are experimentally resolved in fluctuations, dissipation, hot-electron transport, transistor frequency performance, transistor phase noise and transistor reliability. In particular, a slower degradation and a faster operation of GaN-based HFETs take place inside the electron density window where the resonant plasmon-assisted ultrafast dissipation of the LO-mode heat comes into play. A novel heterostructure design for the possible improvement of HFET performance is proposed, implemented and tested. (invited review)

  20. Irrigation water management: Basic principles and applications

    OpenAIRE

    Ella, Victor B.

    2007-01-01

    This presentation defines the term, irrigation, as well as explains the common methods of irrigation in attempt to define the fundamental principles needed to wisely design an irrigation system. It outlines a typical drip irrigation set-up, and discusses management of an irrigation system, including water volume application suggestions. LTRA-5 (Agroforestry and Sustainable Vegetable Production)

  1. Bone mineral density status and frequency of osteoporosis and clinical fractures in 155 patients with psoriatic arthritis followed in a university hospital.

    Science.gov (United States)

    Busquets, Noemi; Vaquero, Carmen Gómez; Moreno, Jesús Rodríguez; Vilaseca, Daniel Roig; Narváez, Javier; Carmona, Loreto; Nolla, Joan M

    2014-01-01

    To assess the bone mineral density (BMD) and the frequency of osteoporosis and clinical fractures in a large group of Spanish patients with psoriatic arthritis (PsA). BMD was determined by DXA in all the patients who were willing to participate and had peripheral PsA regularly evaluated in a tertiary university hospital. All patients underwent a physical examination and general laboratory analysis. We gathered demographic and clinical variables related with BMD and risk of fractures. We also recorded the history of clinical low impact fractures. The population of reference to calculate T-score and Z-score came from a Spanish database. One hundred and fifty-five patients were included (64 postmenopausal women, 26 premenopausal women and 65 men). The clinical forms of PsA were: 46% oligoarticular and 54% polyarticular. Mean disease duration was 13.7±9.4 years and mean ESR was 21.8±13.9mm/h; 66% of patients had received glucocorticoid treatment. We found no differences in BMD status between the patients and the Spanish general population, neither in the whole series nor in each defined subgroup. Frequency of osteoporosis was 16%; it was higher in postmenopausal women (28%) than in men (9%) or premenopausal women (4%). Frequency of clinical fractures was 13%; it accounted specially in postmenopausal women. The magnitude of the problem of osteoporosis in PsA seems to be mild. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  2. Agriculture Irrigation and Water Use

    OpenAIRE

    Bajwa, Rajinder S.; Crosswhite, William M.; Hostetler, John E.; Wright, Olivia W.; United States Department of Agriculture, Economic Research Service

    1992-01-01

    The 17 Western States, plus Arkansas, Florida, and Louisiana, account for 91 percent of all U.S. irrigated acreage, with the Western States alone contributing over 85 percent. This report integrates data on the distribution, characteristics, uses, and management of water resources from a wide variety of data sources. The report includes charts and tables on water use in irrigation; farm data comparing selected characteristics of irrigated and nonirrigated farms; and data on water applicatio...

  3. Increased malaria transmission around irrigation schemes in Ethiopia and the potential of canal water management for malaria vector control.

    Science.gov (United States)

    Kibret, Solomon; Wilson, G Glenn; Tekie, Habte; Petros, Beyene

    2014-09-13

    Irrigation schemes have been blamed for the increase in malaria in many parts of sub-Saharan Africa. However, proper water management could help mitigate malaria around irrigation schemes in this region. This study investigates the link between irrigation and malaria in Central Ethiopia. Larval and adult mosquitoes were collected fortnightly between November 2009 and October 2010 from two irrigated and two non-irrigated (control) villages in the Ziway area, Central Ethiopia. Daily canal water releases were recorded during the study period and bi-weekly correlation analysis was done to determine relationships between canal water releases and larval/adult vector densities. Blood meal sources (bovine vs human) and malaria sporozoite infection were tested using enzyme-linked immunosorbent assay (ELISA). Monthly malaria data were also collected from central health centre of the study villages. Monthly malaria incidence was over six-fold higher in the irrigated villages than the non-irrigated villages. The number of anopheline breeding habitats was 3.6 times higher in the irrigated villages than the non-irrigated villages and the most common Anopheles mosquito breeding habitats were waterlogged field puddles, leakage pools from irrigation canals and poorly functioning irrigation canals. Larval and adult anopheline densities were seven- and nine-fold higher in the irrigated villages than in the non-irrigated villages, respectively, during the study period. Anopheles arabiensis was the predominant species in the study area. Plasmodium falciparum sporozoite rates of An. arabiensis and Anopheles pharoensis were significantly higher in the irrigated villages than the non-irrigated villages. The annual entomological inoculation rate (EIR) calculated for the irrigated and non-irrigated villages were 34.8 and 0.25 P. falciparum infective bites per person per year, respectively. A strong positive correlation was found between bi-weekly anopheline larval density and canal water

  4. Irrigation management of sigmoid colostomy.

    Science.gov (United States)

    Jao, S W; Beart, R W; Wendorf, L J; Ilstrup, D M

    1985-08-01

    Questionnaires were sent to 270 patients who had undergone abdominoperineal resection and sigmoid colostomy at the Mayo Clinic, Rochester, Minn, during the ten years from 1972 to 1982; 223 patients returned their questionnaires with evaluable data. Sixty percent of the patients were continent with irrigation, and 22% were incontinent with irrigation. Eighteen percent had discontinued irrigation for various reasons. The proportion continent was higher in women, younger patients, and previously constipated patients. A poorly constructed colostomy may cause acute angle, parastoma hernia, stomal prolapse, or stenosis and thus be the cause of failure of irrigation.

  5. Simulation, measurement, and emulation of photovoltaic modules using high frequency and high power density power electronic circuits

    Science.gov (United States)

    Erkaya, Yunus

    system variables so that any PV module can be emulated as the design requires. A non-synchronous buck converter is proposed for the emulation of a single, high-power PV module using traditional silicon devices. With the proof-of-concept working and improvements in efficiency, power density and steady-state errors made, dynamic tests were performed using an inverter connected to the PV emulator. In order to improve the dynamic characteristics, a synchronous buck converter topology is proposed along with the use of advanced GaNFET devices which resulted in very high power efficiency and improved dynamic response characteristics when emulating PV modules.

  6. Soil water sensors for irrigation management-What works, what doesn't, and why

    Science.gov (United States)

    Irrigation scheduling can be greatly improved if accurate soil water content data are available. There are a plethora of available soil water sensing systems, but those that are practical for irrigation scheduling are divided into two major types: the frequency domain (capacitance) sensors and the t...

  7. Assessment of Irrigation Water Quality and Suitability for Irrigation in ...

    African Journals Online (AJOL)

    A number of factors like geology, soil, effluents, sewage disposal and other environmental conditions in which the water stays or moves and interacts are among the factors that affect the quality of irrigation water. This study was conducted to determine the quality and suitability of different water sources for irrigation purpose ...

  8. Effect of irrigation on heavy metals content of wastewater irrigated ...

    African Journals Online (AJOL)

    There is an urgent need to educate farmers on the dangers of the presence of heavy metals in soils as well as the quality of irrigation water especially if it comes from tanning industries for increased crop production. Accordingly, soil and irrigation wastewater study was conducted to assess the concentrations of heavy ...

  9. Principles of root water uptake, soil salinity and crop yield for optimizing irrigation management

    International Nuclear Information System (INIS)

    Dirksen, C.

    1983-01-01

    The paper reviews the principles of water and salt transport, root water uptake, crop salt tolerance, water quality, and irrigation methods which should be considered in optimizing irrigation management for sustained, viable agriculture with protection of the quality of land and water resources. In particular, the advantages of high-frequency irrigation at small leaching fractions with closed systems are discussed, for which uptake-weighted mean salinity is expected to correlate best with crop yields. Optimization of irrigation management depends on the scale considered. Non-technical problems which are often much harder to solve than technical problems, may well be most favourable for new projects in developing countries. (author)

  10. Absolute atomic oxygen and nitrogen densities in radio-frequency driven atmospheric pressure cold plasmas: Synchrotron vacuum ultra-violet high-resolution Fourier-transform absorption measurements

    International Nuclear Information System (INIS)

    Niemi, K.; O'Connell, D.; Gans, T.; Oliveira, N. de; Joyeux, D.; Nahon, L.; Booth, J. P.

    2013-01-01

    Reactive atomic species play a key role in emerging cold atmospheric pressure plasma applications, in particular, in plasma medicine. Absolute densities of atomic oxygen and atomic nitrogen were measured in a radio-frequency driven non-equilibrium plasma operated at atmospheric pressure using vacuum ultra-violet (VUV) absorption spectroscopy. The experiment was conducted on the DESIRS synchrotron beamline using a unique VUV Fourier-transform spectrometer. Measurements were carried out in plasmas operated in helium with air-like N 2 /O 2 (4:1) admixtures. A maximum in the O-atom concentration of (9.1 ± 0.7)×10 20 m −3 was found at admixtures of 0.35 vol. %, while the N-atom concentration exhibits a maximum of (5.7 ± 0.4)×10 19 m −3 at 0.1 vol. %

  11. Measurement of nucleation site density, bubble departure diameter and frequency in pool boiling of water using high-speed infrared and optical cameras

    Energy Technology Data Exchange (ETDEWEB)

    Gerardi, Craig; Buongiorno, Jacopo; Hu, Lin-wen; McKrell, Thomas [Massachusetts Institute of Technology, Cambridge, MA (United States)], e-mail: jacopo@mit.edu

    2009-07-01

    A high-speed video and IR thermometry based technique has been used to obtain time and space resolved information on bubble nucleation and boiling heat transfer. This approach provides a fundamental and systematic method for investigating nucleate boiling in a very detailed fashion. Data on bubble departure diameter and frequency, growth and wait times, and nucleation site density are measured with relative ease. The data have been compared to the traditional decades-old and poorly-validated nucleate-boiling models and correlations. The agreement between the data and the models is relatively good. This study also shows that new insights into boiling heat transfer mechanisms can be obtained with the present technique. For example, our data and analysis suggest that a large contribution to bubble growth comes from heat transfer through the superheated liquid layer in addition to micro layer evaporation. (author)

  12. Measurement of nucleation site density, bubble departure diameter and frequency in pool boiling of water using high-speed infrared and optical cameras

    International Nuclear Information System (INIS)

    Gerardi, Craig; Buongiorno, Jacopo; Hu, Lin-wen; McKrell, Thomas

    2009-01-01

    A high-speed video and IR thermometry based technique has been used to obtain time and space resolved information on bubble nucleation and boiling heat transfer. This approach provides a fundamental and systematic method for investigating nucleate boiling in a very detailed fashion. Data on bubble departure diameter and frequency, growth and wait times, and nucleation site density are measured with relative ease. The data have been compared to the traditional decades-old and poorly-validated nucleate-boiling models and correlations. The agreement between the data and the models is relatively good. This study also shows that new insights into boiling heat transfer mechanisms can be obtained with the present technique. For example, our data and analysis suggest that a large contribution to bubble growth comes from heat transfer through the superheated liquid layer in addition to micro layer evaporation. (author)

  13. How Patients Experience Antral Irrigation

    Directory of Open Access Journals (Sweden)

    Karin Blomgren

    2015-01-01

    Full Text Available Background Antral irrigation earlier had an important role in the diagnosis and treatment of rhinosinusitis. Nowadays, it is often considered too unpleasant. However, the experience of patients of this procedure has been very seldom evaluated. Nor has the effect on pain in rhinosinusitis been evaluated. The aim of this study was to evaluate patients’ experience of discomfort and pain during antral irrigation. We also assessed facial pain caused by rhinosinusitis before the procedure and pain soon after the procedure. Methods Doctors and 121 patients completed their questionnaires independently after antral irrigation in a university clinic, in a private hospital, and at a communal health center. Results Patients experienced mild pain during antral irrigation (mean and median visual analog scale score: <3. Their experience of pain during antral irrigation was closely comparable to pain during dental calculus scaling. Facial pain assessed before antral irrigation decreased quickly after the procedure. Conclusions Antral irrigation was well tolerated as an outpatient procedure. The procedure seems to relieve facial pain caused by the disease quickly. The role of antral irrigation in the treatment of acute rhinosinusitis will need further investigation.

  14. Irrigation management in organic greenhouse

    NARCIS (Netherlands)

    Voogt, W.; Balendonck, J.; Berkelmans, R.; Enthoven, N.

    2017-01-01

    Irrigation in protected cultivation is essential due to the absence of natural precipitation. High evapotranspiration, due to higher temperature and prolonged cropping period, requires ample an adequate supply of water. The water supply in a greenhouse is solely carried out by irrigation and thus

  15. Scintigraphic assessment of colostomy irrigation.

    Science.gov (United States)

    Christensen, P.; Olsen, N.; Krogh, K.; Laurberg, S.

    2002-09-01

    OBJECTIVE: This study aims to evaluate colonic transport following colostomy irrigation with a new scintigraphic technique. MATERIALS AND METHODS: To label the bowel contents 19 patients (11 uncomplicated colostomy irrigation, 8 complicated colostomy irrigation) took 111In-labelled polystyrene pellets one and two days before investigation. 99mTc-DTPA was mixed with the irrigation fluid to assess its extent within the bowel. Scintigraphy was performed before and after a standardized washout procedure. The colon was divided into three segments 1: the caecum andascending colon; 2: the transverse colon; 3: the descending and sigmoid colon. Assuming ordered evacuation of the colon, the contribution of each colonic segment to the total evacuation was expressed as a percentage of the original segmental counts. These were added to reach a total defaecation score (range: 0-300). RESULTS: In uncomplicated colostomy irrigation, the median defaecation score was 235 (range: 145-289) corresponding to complete evacuation of the descending and transverse colon and 35% evacuation of the caecum/ascending colon. In complicated colostomy irrigation it was possible to distinguish specific emptying patterns. The retained irrigation fluid reached the caecum in all but one patient. CONCLUSION: Scintigraphy can be used to evaluate colonic emptying following colostomy irrigation.

  16. Are There Infinite Irrigation Trees?

    Science.gov (United States)

    Bernot, M.; Caselles, V.; Morel, J. M.

    2006-08-01

    In many natural or artificial flow systems, a fluid flow network succeeds in irrigating every point of a volume from a source. Examples are the blood vessels, the bronchial tree and many irrigation and draining systems. Such systems have raised recently a lot of interest and some attempts have been made to formalize their description, as a finite tree of tubes, and their scaling laws [25], [26]. In contrast, several mathematical models [5], [22], [10], propose an idealization of these irrigation trees, where a countable set of tubes irrigates any point of a volume with positive Lebesgue measure. There is no geometric obstruction to this infinitesimal model and general existence and structure theorems have been proved. As we show, there may instead be an energetic obstruction. Under Poiseuille law R(s) = s -2 for the resistance of tubes with section s, the dissipated power of a volume irrigating tree cannot be finite. In other terms, infinite irrigation trees seem to be impossible from the fluid mechanics viewpoint. This also implies that the usual principle analysis performed for the biological models needs not to impose a minimal size for the tubes of an irrigating tree; the existence of the minimal size can be proven from the only two obvious conditions for such irrigation trees, namely the Kirchhoff and Poiseuille laws.

  17. Influencing Factors and Simplified Model of Film Hole Irrigation

    Directory of Open Access Journals (Sweden)

    Yi-Bo Li

    2017-07-01

    Full Text Available Film hole irrigation is an advanced low-cost and high-efficiency irrigation method, which can improve water conservation and water use efficiency. Given its various advantages and potential applications, we conducted a laboratory study to investigate the effects of soil texture, bulk density, initial soil moisture, irrigation depth, opening ratio (ρ, film hole diameter (D, and spacing on cumulative infiltration using SWMS-2D. We then proposed a simplified model based on the Kostiakov model for infiltration estimation. Error analyses indicated SWMS-2D to be suitable for infiltration simulation of film hole irrigation. Additional SWMS-2D-based investigations indicated that, for a certain soil, initial soil moisture and irrigation depth had the weakest effects on cumulative infiltration, whereas ρ and D had the strongest effects on cumulative infiltration. A simplified model with ρ and D was further established, and its use was then expanded to different soils. Verification based on seven soil types indicated that the established simplified double-factor model effectively estimates cumulative infiltration for film hole irrigation, with a small mean average error of 0.141–2.299 mm, a root mean square error of 0.177–2.722 mm, a percent bias of −2.131–1.479%, and a large Nash–Sutcliffe coefficient that is close to 1.0.

  18. Soil salinisation and irrigation management of date palms in a Saharan environment.

    Science.gov (United States)

    Haj-Amor, Zied; Ibrahimi, Mohamed-Khaled; Feki, Nissma; Lhomme, Jean-Paul; Bouri, Salem

    2016-08-01

    The continuance of agricultural production in regions of the world with chronic water shortages depends upon understanding how soil salinity is impacted by irrigation practises such as water salinity, irrigation frequency and amount of irrigation. A two-year field study was conducted in a Saharan oasis of Tunisia (Lazala Oasis) to determine how the soil electrical conductivity was affected by irrigation of date palms with high saline water. The study area lacked a saline shallow water table. Field results indicate that, under current irrigation practises, soil electrical conductivity can build up to levels which exceed the salt tolerance of date palm trees. The effects of irrigation practises on the soil electrical conductivity were also evaluated using model simulations (HYDRUS-1D) of various irrigation regimes with different frequencies, different amounts of added water and different water salinities. The comparison between the simulated and observed results demonstrated that the model gave an acceptable estimation of water and salt dynamics in the soil profile, as indicated by the small values of root mean square error (RMSE) and the high values of the Nash-Sutcliffe model efficiency coefficient (NSE). The simulations demonstrated that, under field conditions without saline shallow groundwater, saline irrigation water can be used to maintain soil electrical conductivity and soil water content at safe levels (soil electrical conductivity soil water content >0.04 cm(3) cm(-3)) if frequent irrigations with small amounts of water (90 % of the evapotranspiration requirements) were applied throughout the year.

  19. Simulation of a two-dimensional sheath over a flat insulator-conductor interface on a radio-frequency biased electrode in a high-density plasma

    International Nuclear Information System (INIS)

    Kim, Doosik; Economou, Demetre J.

    2004-01-01

    A combined fluid/Monte Carlo (MC) simulation was developed to study the two-dimensional (2D) sheath over a flat insulator/conductor interface on a radio-frequency (rf) biased electrode in a high-density plasma. The insulator capacitance increased the local impedance between the plasma and the bias voltage source. Thus, for uniform ion density and electron temperature far away from the wall, the sheath potential over the insulator was only a fraction of that over the conductor, resulting in a thinner sheath over the insulator. The fluid model provided the spatiotemporal profiles of the 2D sheath electric field. These were used as input to the MC simulation to compute the ion energy distribution (IED) and ion angular distribution (IAD) at different locations on the surface. The ion flux, IED, and IAD changed drastically across the insulator/conductor interface due to the diverging rf electric field in the distorted sheath. The ion flux was larger on the conductor at the expense of that on the insulator. Both the ion impact angle and angular spread increased progressively as the material interface was approached. The ion impact energy and energy spread were smaller on the insulator as compared to the conductor. For given plasma parameters, as the insulator thickness was increased, the sheath potential and thickness over the insulator decreased, and sheath distortion became more pronounced

  20. Generating an AC amplitude magnetic flux density value up to 150 μT at a frequency up to 100 kHz

    Science.gov (United States)

    Ulvr, Michal; Polonský, Jakub

    2017-05-01

    AC magnetic field analyzers with a triaxial coil probe are widely used by health and safety professionals, in manufacturing, and in service industries. For traceable calibration of these analyzers, it is important to be able to generate a stable, homogeneous reference AC magnetic flux density (MFD). In this paper, the generating of AC amplitude MFD value of 150 μT by single-layer Helmholtz type solenoid, described in previous work, was expanded up to a frequency of 100 kHz using the effect of serial resonance. A programmable capacitor array has been developed with a range of adjustable values from 50 pF to 51225 pF. In addition, the multi-layer search coil with a nominal area turns value of 1.3m2, used for adjusting AC MFD in the solenoid, has been modified by a transimpedance amplifier for use in a wider frequency range than up to 3 kHz. The possibility of using the programmable capacitor array up to 150 kHz has also been tested. An AC amplitude MFD value of 150 μT can be generated with expanded uncertainty better than 0.6% up to 100 kHz.

  1. Electron density modulation in a pulsed dual-frequency (2/13.56 MHz) dual-antenna inductively coupled plasma discharge

    Energy Technology Data Exchange (ETDEWEB)

    Sirse, Nishant, E-mail: nishant.sirse@dcu.ie [Plasma Research Laboratory, School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); Mishra, Anurag [Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Yeom, Geun Y. [Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, South Korea and SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, Gyeunggi-do 440-746 (Korea, Republic of); Ellingboe, Albert R. [Plasma Research Laboratory, School of Physical Sciences, Dublin City University, Dublin 9, Ireland and Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

    2016-09-15

    The electron density, n{sub e}, modulation is measured experimentally using a resonance hairpin probe in a pulsed, dual-frequency (2/13.56 MHz), dual-antenna, inductively coupled plasma discharge produced in argon-C{sub 4}F{sub 8} (90–10) gas mixtures. The 2 MHz power is pulsed at a frequency of 1 kHz, whereas 13.56 MHz power is applied in continuous wave mode. The discharge is operated at a range of conditions covering 3–50 mTorr, 100–600 W 13.56 MHz power level, 300–600 W 2 MHz peak power level, and duty ratio of 10%–90%. The experimental results reveal that the quasisteady state n{sub e} is greatly affected by the 2 MHz power levels and slightly affected by 13.56 MHz power levels. It is observed that the electron density increases by a factor of 2–2.5 on increasing 2 MHz power level from 300 to 600 W, whereas n{sub e} increases by only ∼20% for 13.56 MHz power levels of 100–600 W. The rise time and decay time constant of n{sub e} monotonically decrease with an increase in either 2 or 13.56 MHz power level. This effect is stronger at low values of 2 MHz power level. For all the operating conditions, it is observed that the n{sub e} overshoots at the beginning of the on-phase before relaxing to a quasisteady state value. The relative overshoot density (in percent) depends on 2 and 13.56 MHz power levels. On increasing gas pressure, the n{sub e} at first increases, reaching to a maximum value, and then decreases with a further increase in gas pressure. The decay time constant of n{sub e} increases monotonically with pressure, increasing rapidly up to 10 mTorr gas pressure and at a slower rate of rise to 50 mTorr. At a fixed 2/13.56 MHz power level and 10 mTorr gas pressure, the quasisteady state n{sub e} shows maximum for 30%–40% duty ratio and decreases with a further increase in duty ratio.

  2. The effect of different sowing patterns and deficit irrigation ...

    African Journals Online (AJOL)

    . The responses of sweet corn (Zea mays) to irrigation frequency and sowing patterns were studied in the field from December 2005 to December 2006. This research was laid out in split plot, with water quantity as main plot and sowing ...

  3. On the role of density and attenuation in 3D multi-parameter visco-acoustic VTI frequency-domain FWI: an OBC case study from the North Sea

    Science.gov (United States)

    Operto, S.; Miniussi, A.

    2018-03-01

    Three-dimensional frequency-domain full waveform inversion (FWI) is applied on North Sea wide-azimuth ocean-bottom cable data at low frequencies (≤ 10 Hz) to jointly update vertical wavespeed, density and quality factor Q in the visco-acoustic VTI approximation. We assess whether density and Q should be viewed as proxy to absorb artefacts resulting from approximate wave physics or are valuable for interpretation in presence of saturated sediments and gas. FWI is performed in the frequency domain to account for attenuation easily. Multi-parameter frequency-domain FWI is efficiently performed with a few discrete frequencies following a multi-scale frequency continuation. However, grouping a few frequencies during each multi-scale step is necessary to mitigate acquisition footprint and match dispersive shallow guided waves. Q and density absorb a significant part of the acquisition footprint hence cleaning the velocity model from this pollution. Low Q perturbations correlate with low velocity zones associated with soft sediments and gas cloud. However, the amplitudes of the Q perturbations show significant variations when the inversion tuning is modified. This dispersion in the Q reconstructions is however not passed on the velocity parameter suggesting that cross-talks between first-order kinematic and second-order dynamic parameters are limited. The density model shows a good match with a well log at shallow depths. Moreover, the impedance built a posteriori from the FWI velocity and density models shows a well-focused image with however local differences with the velocity model near the sea bed where density might have absorbed elastic effects. The FWI models are finally assessed against time-domain synthetic seismogram modelling performed with the same frequency-domain modelling engine used for FWI.

  4. Effect of different drip irrigation regimes on yield and oil quality of sunflower

    Directory of Open Access Journals (Sweden)

    Semih Metin SEZEN

    2016-06-01

    Full Text Available This study examines the effects of different irrigation regimes on yield, yield components, oil yield and quality and water use of sunflower (Oleko variety irrigated with a drip system under field conditions in 2010 and 2011 growing seasons at the Alata Horticultural Research Institute, Tarsus Soil and Water Resources area in the Mediterranean region of Turkey. Irrigation regimes consisted of three irrigation intervals (A1:= 25 mm; A2:= 50 mm; A3: = 75 mm of cumulative pan evaporation and six irrigation levels (I1=0.50, I2=0.75, I3=1.00 and I4=1.25. In addition, I5=PRD75 and I6=PRD50 treatments were considered. They received 75 and 50% of the full irrigation (I3 treatment from alternative laterals, respectively. Also, rainfed treatment is a control plot in the experiment. Maximum and minimum yields were obtained from the A2I4 and rainfed treatments, respectively in all experimental years. As the irrigation level value decreased the total yields in each irrigation interval also decreased. Seasonal irrigation amounts in the treatments varied from 199 mm to 563 mm in the experimental years. Seasonal evapotranspiration values in the treatments varied from 243 mm to 611 mm in the experimental years. Both irrigation amounts and irrigation frequencies had significantly effects on oil content of sunflower. The saturated (palmitic and stearic acid and unsaturated (oleic and linoleic acid fatty acid contents were significantly affected by water stress. In conclusion, A2I4 irrigation regime is recommended for sunflower production in the Mediterranean region in order to attain higher yields with improved quality. In case of water shortage, A2I13 irrigation regime is recommended to increase sunflower yield and quality.

  5. Response of Onion ( Allium cepa L.) to Irrigation Intervals and Plant ...

    African Journals Online (AJOL)

    08 at the Teaching and Research Farm of the College of Agriculture, Zuru, Kebbi State, Nigeria. The objective was to investigate the response of onion to irrigation interval and plant population density. The treatments consisted of factorial ...

  6. The effect of feeding frequency, water temperature, and stocking density on the growth of river puffer Takifugu obscurus reared in a zero-exchange water system

    Directory of Open Access Journals (Sweden)

    Gwang-Yeol Yoo

    2016-07-01

    Full Text Available Abstract The effects of daily feeding frequency (Exp I, water temperature (Exp II, and stocking density (Exp III on the growth of river puffer, Takifugu obscurus, juvenile fish of 10 and 40 g in body weight were examined to develop effective techniques to produce river puffer in a non-exchange water system. In Exp I, fish were fed commercial floating feed with 45 % protein one to five times per day to apparent satiation each by hand daily for 8 weeks at 25 °C. In both the 10- and 40-g size groups, the final body weight, daily feed consumption, and weight gain of fish fed one meal per day were significantly lower than those of fish fed five meals per day (P < 0.05. However, there were no significant differences in the final body weight, daily feed consumption, and weight gain among fish fed two, three, and five meals per day. Feed efficiency showed decreasing tendency with increasing size of fish. In Exp II, fish of 10 and 40 g in initial body weight were reared with the commercial feed at 15–30 °C for 8 weeks. The weight gain of fish increased with raising water temperature up to 25 °C and decreased drastically at 30 °C for both sizes. The Q10 of specific growth rate was decreased with raising water temperature from 5.04 (temperature interval, 15–20 °C to 0.66 (25–30 °C for the 10-g fish and from 4.98 to 0.31 for the 40-g fish. In Exp III, the effect of stocking density on growth was examined with fish of 10 and 40 g in initial body weight. The final body weight for initial stocking densities of 4, 8, and 12 kg/m3 was significantly higher than that of 20 kg/m3 for the 10-g fish, and the final stocking density reached 10.1, 19.2, 28.7, and 39.9 kg/m3, respectively. For the 40-g fish, the final body weight for initial stocking densities of 3 and 6 kg/m3 was significantly higher than that of 9 and 15 kg/m3 and the final stocking density reached 7.38, 13.5, 17.1, and 27.5 kg/m3, respectively (P < 0.05. In both

  7. Development of fine and coarse roots of Thuja occidentalis 'Brabant' in non-irrigated and drip irrigated field plots

    NARCIS (Netherlands)

    Pronk, A.A.; Willigen, de P.; Heuvelink, E.; Challa, H.

    2002-01-01

    Aboveground dry mass, total root dry mass and root length density of the fine roots of Thuja occidentalis `Brabant' were determined under non- and drip-irrigated field conditions. Two-dimensional diffusion parameters for dynamic root growth were estimated based on dry mass production of the fine

  8. Use of Irrigation to Extend the Seeding Window for Final Reclamation at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    TRW Environmental Safety

    2000-01-01

    The U.S. Department of Energy has implemented a program to investigate the feasibility of various techniques for reclaiming lands disturbed during site characterization at Yucca Mountain. As part of this program, two studies were conducted in 1997 to assess the effects of combinations of seeding date (date that seeds are planted) and supplemental irrigation on densities of native plant species at Yucca Mountain. Study objectives were to (1) determine whether the traditional seeding window (October-December) could be extended through combinations of seeding date and irrigation date, (2) determine which combination of seeding date and irrigation was most successful, and (3) assess the effects of irrigation versus natural precipitation on seedling establishment. In the first study, a multi-species seed mix of 16 native species was sown into plots on four dates (12/96, 2/97, 3/97, and 4/97). Irrigation treatments were control (no irrigation) or addition of 80 mm of supplemental water applied over a one month period. Plant densities were sampled in August and again in October, 1997. In the second study, Larrea tridentata and Lycium andersonii, two species that are common at Yucca Mountain, but difficult to establish from seed, were sown together into plots in January and August, 1997. Half the plots were irrigated with approximately 250 mm of water between August 18 and September 11, while the remaining plots received no irrigation (control). Plant densities were sampled in October, 1997. The August census for the multi-species mix study showed irrigated plots that were sown in February, March and April had higher plant densities and more species than plots that were not irrigated. Irrigation had no effect on plant densities on plots that were seeded in December. Plots were used again in October following 18 mm of precipitation in September. Densities of three species, Ambrosia dumosa, Hymenoclea salsola, and L. tridentata, (warm-season species) were lower on irrigated

  9. Sensing technologies for precision irrigation

    CERN Document Server

    Ćulibrk, Dubravko; Minic, Vladan; Alonso Fernandez, Marta; Alvarez Osuna, Javier; Crnojevic, Vladimir

    2014-01-01

    This brief provides an overview of state-of-the-art sensing technologies relevant to the problem of precision irrigation, an emerging field within the domain of precision agriculture. Applications of wireless sensor networks, satellite data and geographic information systems in the domain are covered. This brief presents the basic concepts of the technologies and emphasizes the practical aspects that enable the implementation of intelligent irrigation systems. The authors target a broad audience interested in this theme and organize the content in five chapters, each concerned with a specific technology needed to address the problem of optimal crop irrigation. Professionals and researchers will find the text a thorough survey with practical applications.

  10. Effects of irrigation levels on interactions among Lygus hesperus (Hemiptera: Miridae), insecticides, and predators in cotton.

    Science.gov (United States)

    Asiimwe, Peter; Naranjo, Steven E; Ellsworth, Peter C

    2014-04-01

    Variation in plant quality and natural enemy abundance plays an important role in insect population dynamics. In manipulative field studies, we evaluated the impact of varying irrigation levels and insecticide type on densities of Lygus hesperus Knight and the arthropod predator community in cotton. Three watering levels were established via irrigations timed according to three levels of percent soil water depletion (SWD): 20, 40, or 60, where 40% SWD is considered standard grower practice, 60% represents a deficit condition likely to impose plant productivity losses, and 20% represents surplus conditions with likely consequences on excessive vegetative plant production. The two key L. hesperus insecticides used were the broad-spectrum insecticide acephate and the selective insecticide flonicamid, along with an untreated check. We hypothesized that densities of L. hesperus and its associated predators would be elevated at higher irrigation levels and that insecticides would differentially impact L. hesperus and predator dynamics depending on their selectivity. L. hesperus were more abundant at the higher irrigation level (20% SWD) but the predator densities were unaffected by irrigation levels. Both L. hesperus and its predators were affected by the selectivity of the insecticide with highest L. hesperus densities and lowest predator abundance where the broad spectrum insecticide (acephate) was used. There were no direct interactions between irrigation level and insecticides, indicating that insecticide effects on L. hesperus and its predators were not influenced by the irrigation levels used here. The implications of these findings on the overall ecology of insect-plant dynamics and yield in cotton are discussed.

  11. Colostomy irrigation: are we offering it enough?

    Science.gov (United States)

    Woodhouse, Fran

    This article discusses the use of irrigation for suitable colostomists and reasons why it can have a very positive effect on lifestyle. While it is evidence-based it also includes anecdotal tips from patients who irrigate. The suitability of patients to irrigate and ways to 'get started' with irrigation are discussed.

  12. Evaluation model development for sprinkler irrigation uniformity ...

    African Journals Online (AJOL)

    use

    Sprinkle and trickle irrigation. The. Blackburn Press, New Jersey, USA. Li JS, Rao MJ (1999). Evaluation method of sprinkler irrigation nonuniformity. Trans. CSAE. 15(4): 78-82. Lin Z, Merkley GP (2011). Relationships between common irrigation application uniformity indicators. Irrig Sci. Online First™, 27 January. 2011.

  13. Wireless sensor networks for irrigation management

    Science.gov (United States)

    Sustaining an adequate food supply for the world's population will require advancements in irrigation technology and improved irrigation management. Site-specific irrigation and automatic irrigation scheduling are examples of strategies to deal with declining arable land and limited fresh water reso...

  14. Condensation irrigation a system for desalination and irrigation

    International Nuclear Information System (INIS)

    Lindblom, J.; Nordell, B

    2006-01-01

    condensation irrigation is a system for both desalination and irrigation. The principles is that humidified air is let into an underground horizontal pipe system, where the air is cooled by the ground and humidity falls out as fresh water. The humidification could e.g. be achieved by evaporation of seawater in solar stills or any other heat source. By using drainage pipes for underground air transportation the water percolates into the soil, thereby irrigating the land. This study focuses on drinking water production, which means that humid air is led into plan pipes where the condensed water is collected at the pipe endings. Numerical simulations gave a study-state diurnal mean water production of 1.8 kg per meter of pipe over a 50 m pipe. Shorter pipes result in a greater mean production rate. Since the heat transfer of drainage pipes would be greater, current study indicates that condensation irrigation is a promising method for desalination and irrigation. Performed studies in condensation irrigation started at LTU in 2003. Current paper reports the initial theoretical work on the system.(Author)

  15. State updating of a distributed hydrological model with Ensemble Kalman Filtering: Effects of updating frequency and observation network density on forecast accuracy

    Science.gov (United States)

    Rakovec, O.; Weerts, A.; Hazenberg, P.; Torfs, P.; Uijlenhoet, R.

    2012-12-01

    This paper presents a study on the optimal setup for discharge assimilation within a spatially distributed hydrological model (Rakovec et al., 2012a). The Ensemble Kalman filter (EnKF) is employed to update the grid-based distributed states of such an hourly spatially distributed version of the HBV-96 model. By using a physically based model for the routing, the time delay and attenuation are modelled more realistically. The discharge and states at a given time step are assumed to be dependent on the previous time step only (Markov property). Synthetic and real world experiments are carried out for the Upper Ourthe (1600 km2), a relatively quickly responding catchment in the Belgian Ardennes. The uncertain precipitation model forcings were obtained using a time-dependent multivariate spatial conditional simulation method (Rakovec et al., 2012b), which is further made conditional on preceding simulations. We assess the impact on the forecasted discharge of (1) various sets of the spatially distributed discharge gauges and (2) the filtering frequency. The results show that the hydrological forecast at the catchment outlet is improved by assimilating interior gauges. This augmentation of the observation vector improves the forecast more than increasing the updating frequency. In terms of the model states, the EnKF procedure is found to mainly change the pdfs of the two routing model storages, even when the uncertainty in the discharge simulations is smaller than the defined observation uncertainty. Rakovec, O., Weerts, A. H., Hazenberg, P., Torfs, P. J. J. F., and Uijlenhoet, R.: State updating of a distributed hydrological model with Ensemble Kalman Filtering: effects of updating frequency and observation network density on forecast accuracy, Hydrol. Earth Syst. Sci. Discuss., 9, 3961-3999, doi:10.5194/hessd-9-3961-2012, 2012a. Rakovec, O., Hazenberg, P., Torfs, P. J. J. F., Weerts, A. H., and Uijlenhoet, R.: Generating spatial precipitation ensembles: impact of

  16. On the possibility of gamma-laser pumping occurring at a charged particle counter motion and in density-modulated electron beams by a high frequency intensive radiation

    International Nuclear Information System (INIS)

    Maksyuta, N.V.

    1999-01-01

    The given report deals with the problem of motion and radiation of relativistic electron in a field of opposite plane density-modulated relativistic electron beam. Physical essence of high-frequency intensive radiation origin could be explained, first by the additional Lorentz reduction of the electron beam modulation period (modulation period Λ in a laboratory co-ordinate system reduces by a factor γ as compared with the modulation period in a beam co-ordinate system) and, secondly, a simultaneous γ-fold increase of transverse components of relativistic electrons of the beam electric and magnetic fields. Such a moving modulated electron beam can be regarded as a dynamic micro-ondulator. Unlike static micro-ondulators we can observe here one more positive moment along with a small period Λ = Λ'/γ, i.e. the electric and magnetic fields in a transverse direction are changed according to the law of exp(-2πx/Λ'). It means that charged particle interaction with a dynamic micro-ondulator will be effective in a wide range of transverse distances, i.e., to get an intensive short wave radiation one can use charged particle beams with rather large apertures which leads to an additional radiation intensity increase. A discussion is given showing that the proposed dynamic modulator possesses some essential merits. A detailed calculation is presented. (author)

  17. Measurement of the electronic density of ionised media by hyper frequency methods; Mesure de la densite electronique des milieux ionises par des methodes hyperfrequences

    Energy Technology Data Exchange (ETDEWEB)

    Consoli, T [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    Within the limits of the I.N.S.T.N. courses on plasmas, this analytical study summarizes the articles quoted in the references on hyper-frequency techniques for the measurement of electronic density of an ionised gas. It is neither exhaustive nor complete and further details may be obtained by referring to the works mentioned. The first part, devoted to the theoretical side, concert the propagation of electromagnetic waves ionised media and the excitation of stationary raves in electromagnetic cavities. The second part deals with the measurement techniques themselves. It includes those techniques which hare become classic, and also more recent ones being developed in various laboratories and in the Service of Applied Physics at Saclay. (author) [French] Dans le cadre des cours sur les plasmas a l'l.N.S.T. cette etude d'analyse resume les articles cites en bibliographie sur les techniques hyperfrequences pour la mesure de la densite electronique d'un gas ionise. Elle n'est ni exhaustive, ni complete. Pour plus de details on voudra bien se rapporter aux travaux mentionnes. La premiere partie consacree a des rappels theoriques, concerne la propagation des ondes electromagnetiques dans les milieux ionises et sur l'excitation d'ondes stationnaires dans les cavites electromagnetiques. La seconde se rapporte aux techniques de mesures proprement dites. On a fait figurer dans cette partie des techniques devenues classiques et celles plus recentes en cours d'etudes dans divers laboratoires et au Service de Physique Appliquee a SACLAY. (auteur)

  18. performance evaluation of sprinkler irrigation system at mambilla

    African Journals Online (AJOL)

    HOD

    ratio (DPR), irrigation productivity (IP), labour requirements and water quality. Standard procedure was ... The exchangeable cations analysis of Kakara irrigation ... Keywords: Tea, irrigation System, Performance Evaluation. 1. INTRODUCTION.

  19. Impact of urban contamination of the La Paz River basin on thermotolerant coliform density and occurrence of multiple antibiotic resistant enteric pathogens in river water, irrigated soil and fresh vegetables.

    Science.gov (United States)

    Poma, Violeta; Mamani, Nataniel; Iñiguez, Volga

    2016-01-01

    La Paz River in Andean highlands is heavily polluted with urban run-off and further contaminates agricultural lowlands and downstream waters at the Amazon watershed. Agricultural produce at this region is the main source of vegetables for the major Andean cities of La Paz and El Alto. We conducted a 1 year study, to evaluate microbial quality parameters and occurrence of multiple enteropathogenic bacteria (Enterohemorrhagic E. coli-EHEC, Enteroinvasive E. coli or Shigella-EIEC/Shigella, Enteroaggregative E. coli-EAEC, Enteropathogenic E. coli-EPEC Enterotoxigenic E. coli-ETEC and Salmonella) and its resistance to 11 antibiotics. Four sampling locations were selected: a fresh mountain water reservoir (un-impacted, site 1) and downstream sites receiving wastewater discharges (impacted, sites 2-4). River water (sites 1-4, N = 48), and soil and vegetable samples (site 3, N = 24) were collected during dry (April-September) and rainy seasons (October-March). Throughout the study, thermotolerant coliform density values at impacted sites greatly exceeded the guidelines for recreational and agricultural water uses. Seasonal differences were found for thermotolerant coliform density during dry season in water samples nearby a populated and hospital compound area. In contrast to the un-impacted site, where none of the tested enteropathogens were found, 100 % of surface water, 83 % of soil and 67 % of vegetable samples at impacted sites, were contaminated with at least one enteropathogen, being ETEC and Salmonella the most frequently found. ETEC isolates displayed different patterns of toxin genes among sites. The occurrence of enteropathogens was associated with the thermotolerant coliform density. At impacted sites, multiple enteropathogens were frequently found during rainy season. Among isolated enteropathogens, 50 % were resistant to at least two antibiotics, with resistance to ampicillin, nalidixic acid, trimethoprim-sulfamethoxazole and tetracycline commonly

  20. Density distribution of currents induced inside the brain in the heat part of the human model exposed to power frequency electric field; Denryoku shuhasu no denkai ni yori jintai model tobu nonai ni yudosareru denryu mitsudo bunpu

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, A. [Yonago National College of Technology, Tottori (Japan); Isaka, K. [The University of Tokushima, Tokushima (Japan); Kaune, W.

    1998-06-01

    The health effect of the weak current induced in the human body as a result of the interaction between human body and power frequency electric fields has been investigated. However, the current density inside the head part tissues of the human body exposed to the electric fields has little been discussed. In this paper, the finite element method is applied to the analysis of the current density distributions of the head part composed of scalp, skull, cerebrospinal liquid and brain tissues. The basic characteristics of the current density distributions of the brain in the bead part of the axisymmetrical human model have been made clear. 13 refs., 12 figs., 2 tabs.

  1. Irrigation in dose assessments models

    Energy Technology Data Exchange (ETDEWEB)

    Bergstroem, Ulla; Barkefors, Catarina [Studsvik RadWaste AB, Nykoeping (Sweden)

    2004-05-01

    SKB has carried out several safety analyses for repositories for radioactive waste, one of which was SR 97, a multi-site study concerned with a future deep bedrock repository for high-level waste. In case of future releases due to unforeseen failure of the protective multiple barrier system, radionuclides may be transported with groundwater and may reach the biosphere. Assessments of doses have to be carried out with a long-term perspective. Specific models are therefore employed to estimate consequences to man. It has been determined that the main pathway for nuclides from groundwater or surface water to soil is via irrigation. Irrigation may cause contamination of crops directly by e.g. interception or rain-splash, and indirectly via root-uptake from contaminated soil. The exposed people are in many safety assessments assumed to be self-sufficient, i.e. their food is produced locally where the concentration of radionuclides may be the highest. Irrigation therefore plays an important role when estimating consequences. The present study is therefore concerned with a more extensive analysis of the role of irrigation for possible future doses to people living in the area surrounding a repository. Current irrigation practices in Sweden are summarised, showing that vegetables and potatoes are the most common crops for irrigation. In general, however, irrigation is not so common in Sweden. The irrigation model used in the latest assessments is described. A sensitivity analysis is performed showing that, as expected, interception of irrigation water and retention on vegetation surfaces are important parameters. The parameters used to describe this are discussed. A summary is also given how irrigation is proposed to be handled in the international BIOMASS (BIOsphere Modelling and ASSessment) project and in models like TAME and BIOTRAC. Similarities and differences are pointed out. Some numerical results are presented showing that surface contamination in general gives the

  2. Irrigation in dose assessments models

    International Nuclear Information System (INIS)

    Bergstroem, Ulla; Barkefors, Catarina

    2004-05-01

    SKB has carried out several safety analyses for repositories for radioactive waste, one of which was SR 97, a multi-site study concerned with a future deep bedrock repository for high-level waste. In case of future releases due to unforeseen failure of the protective multiple barrier system, radionuclides may be transported with groundwater and may reach the biosphere. Assessments of doses have to be carried out with a long-term perspective. Specific models are therefore employed to estimate consequences to man. It has been determined that the main pathway for nuclides from groundwater or surface water to soil is via irrigation. Irrigation may cause contamination of crops directly by e.g. interception or rain-splash, and indirectly via root-uptake from contaminated soil. The exposed people are in many safety assessments assumed to be self-sufficient, i.e. their food is produced locally where the concentration of radionuclides may be the highest. Irrigation therefore plays an important role when estimating consequences. The present study is therefore concerned with a more extensive analysis of the role of irrigation for possible future doses to people living in the area surrounding a repository. Current irrigation practices in Sweden are summarised, showing that vegetables and potatoes are the most common crops for irrigation. In general, however, irrigation is not so common in Sweden. The irrigation model used in the latest assessments is described. A sensitivity analysis is performed showing that, as expected, interception of irrigation water and retention on vegetation surfaces are important parameters. The parameters used to describe this are discussed. A summary is also given how irrigation is proposed to be handled in the international BIOMASS (BIOsphere Modelling and ASSessment) project and in models like TAME and BIOTRAC. Similarities and differences are pointed out. Some numerical results are presented showing that surface contamination in general gives the

  3. Limiting nutrient emission from a cut rose closed system by high-flux irrigation and low nutrient concentrations?

    NARCIS (Netherlands)

    Baas, R.; Berg, van der D.

    2004-01-01

    A two-year project was aimed at decreasing nutrient emission from closed nutrient systems by using high irrigation rates in order to allow lower EC levels in the presence of accumulated Na and Cl. Experimental variables were growing media, irrigation frequencies, EC and NaCl concentrations for cut

  4. Climate forcing and desert malaria: the effect of irrigation.

    Science.gov (United States)

    Baeza, Andres; Bouma, Menno J; Dobson, Andy P; Dhiman, Ramesh; Srivastava, Harish C; Pascual, Mercedes

    2011-07-14

    Rainfall variability and associated remote sensing indices for vegetation are central to the development of early warning systems for epidemic malaria in arid regions. The considerable change in land-use practices resulting from increasing irrigation in recent decades raises important questions on concomitant change in malaria dynamics and its coupling to climate forcing. Here, the consequences of irrigation level for malaria epidemics are addressed with extensive time series data for confirmed Plasmodium falciparum monthly cases, spanning over two decades for five districts in north-west India. The work specifically focuses on the response of malaria epidemics to rainfall forcing and how this response is affected by increasing irrigation. Remote sensing data for the Normalized Difference Vegetation Index (NDVI) are used as an integrated measure of rainfall to examine correlation maps within the districts and at regional scales. The analyses specifically address whether irrigation has decreased the coupling between malaria incidence and climate variability, and whether this reflects (1) a breakdown of NDVI as a useful indicator of risk, (2) a weakening of rainfall forcing and a concomitant decrease in epidemic risk, or (3) an increase in the control of malaria transmission. The predictive power of NDVI is compared against that of rainfall, using simple linear models and wavelet analysis to study the association of NDVI and malaria variability in the time and in the frequency domain respectively. The results show that irrigation dampens the influence of climate forcing on the magnitude and frequency of malaria epidemics and, therefore, reduces their predictability. At low irrigation levels, this decoupling reflects a breakdown of local but not regional NDVI as an indicator of rainfall forcing. At higher levels of irrigation, the weakened role of climate variability may be compounded by increased levels of control; nevertheless this leads to no significant decrease

  5. Sustainable irrigation in fruit trees

    Directory of Open Access Journals (Sweden)

    Cristos Xiloyannis

    2010-09-01

    Full Text Available Water management in fruit growing, particularly in areas with high water deficit, low rainfall and limited availability of water for irrigation should aid to save water by: i the choice of high efficiency irrigation methods and their correct management; ii the proper choice of the specie, cultivar and rootstock to optimise plant water use; iii the proper choice of the architecture of the canopy and it’s correct management in order to improve water use efficiency; iv the application of regulated deficit irrigation at growth stages less sensitive to water deficit; v strengthening the role of technical assistance for a rapid transfer of knowledge to the growers on the sustainable use of water in fruit growing.

  6. Sustainable irrigation in fruit trees

    Directory of Open Access Journals (Sweden)

    Cristos Xiloyannis

    Full Text Available Water management in fruit growing, particularly in areas with high water deficit, low rainfall and limited availability of water for irrigation should aid to save water by: i the choice of high efficiency irrigation methods and their correct management; ii the proper choice of the specie, cultivar and rootstock to optimise plant water use; iii the proper choice of the architecture of the canopy and it’s correct management in order to improve water use efficiency; iv the application of regulated deficit irrigation at growth stages less sensitive to water deficit; v strengthening the role of technical assistance for a rapid transfer of knowledge to the growers on the sustainable use of water in fruit growing.

  7. [Continent colostomy and colon irrigation].

    Science.gov (United States)

    Kostov, D; Temelkov, T; Kiriazov, E; Ivanov, K; Ignatov, V; Kobakov, G

    2000-01-01

    The authors have studied a functional activity of a continent colostomy at 20 patients, undergone an abdomeno-perineal extirpation of rectum and carried out periodic colonirrigations, during a period of 6 months. A conus type, closed irrigating system has been used. The degree of an incontinency at patients has been compared before and after the beginning of the colonirrigations. The irrigating procedures have reduced spontaneous defications at patients during a week 28 times and have improved the quality of life significantly. The application of colostomy bags has been restricted in 8 (40%) patients. An intraluminal ultrasonographic investigation has been done at 12 (60%) patients at the end of 6 month irrigating period. No changes of the ultrasonographic image of the precolostomic segment of colon has been observed.

  8. AGROCLIMATIC DETERMINANTS OF IRRIGATION NEEDS

    Directory of Open Access Journals (Sweden)

    Leszek Łabędzki

    2016-05-01

    Full Text Available The paper is a review of the so far used in Poland methods and criteria for assessing the needs of irrigation for planning purposes, the assessment because of the agroclimatic conditions and taking into account the soil water retention. Irrigation needs of the most are determined taking into account crop water deficits. This is the factor that is characterized by a shortage of precipitation in relation to the water requirements of crops. Some methods use only the meteorological parameters that determine the state of the atmosphere-soil-plant system, and some also take into account soil water retention and its availability for plants.

  9. Soil Suitability Classification of Tomas Irrigation Scheme for Irrigated ...

    African Journals Online (AJOL)

    The need for sustainable rice production in Nigeria cannot be over-emphasized. Since rice can be grown both under rain-fed and irrigated conditions, the need for soil suitability evaluation becomes very necessary in order for supply to meet up with demand. Six land qualities viz; climate, soil physical properties, drainage, ...

  10. The effect of frequency of defoliation on Themeda triandra in the ...

    African Journals Online (AJOL)

    Tufts of Themeda triandra were subjected to different frequencies of defoliation during a single season under irrigated and non-irrigated conditions. Frequent defoliation (> 5 times per year) severely reduced clipped yield on both moisture treatments. On irrigated treatments, root mass declined and shoot apex elevation was ...

  11. Modernisation Strategy for National Irrigation Systems in the Philippines: Balanac and Sta. Maria River Irrigation Systems

    NARCIS (Netherlands)

    Delos Reyes, M.L.F.

    2017-01-01

    This book examines the nature and impact of irrigation system rehabilitation on increasing the actual area irrigated by the publicly funded canal irrigation systems of the Philippines. It proposes a system diagnosis approach for the development of a more appropriate and climate-smart irrigation

  12. Sustainable management after irrigation system transfer : experiences in Colombia - the RUT irrigation district

    NARCIS (Netherlands)

    Urrutia Cobo, N.

    2006-01-01

    Colombiais a tropical country located in South America. It has a total area of 114 million ha. In Colombia two irrigation sectors are distinguished: the small-scale irrigation and the large-scale irrigation sector. The small-scale irrigation sector is developed on lands

  13. GSM BASED IRRIGATION CONTROL AND MONITORING SYSTEM

    OpenAIRE

    GODFREY A. MILLS; STEPHEN K. ARMOO; AGYEMAN K. ROCKSON; ROBERT A. SOWAH; MOSES A. ACQUAH

    2013-01-01

    Irrigated agriculture is one of the primary water consumers in most parts of the world. With developments in technology, efforts are being channeled into automation of irrigation systems to facilitate remote control of the irrigation system and optimize crop production and cost effectiveness. This paper describes an on-going work on GSM based irrigation monitoring and control systems. The objective of the work is to provide an approach that helps farmers to easily access, manage and regulate ...

  14. Measuring Transpiration to Regulate Winter Irrigation Rates

    Energy Technology Data Exchange (ETDEWEB)

    Samuelson, Lisa [Auburn University

    2006-11-08

    Periodic transpiration (monthly sums) in a young loblolly pine plantation between ages 3 and 6 was measured using thermal dissipation probes. Fertilization and fertilization with irrigation were better than irrigation alone in increasing transpiration of young loblolly pines during winter months, apparently because of increased leaf area in fertilized trees. Irrigation alone did not significantly increase transpiration compared with the non-fertilized and non-irrigated control plots.

  15. Comparative efficiency of trickle and furrow irrigation

    International Nuclear Information System (INIS)

    Hanif, M.; Qureshi, R.H.; Sandhu, G.R.

    1976-01-01

    Comparison of furrow and trickle methods of irrigation to know their relative efficiency with respect to water applied and fertilizer used on tomatoes, cauliflower and lettuce as test crops using canal water, showed a significant saving of about 44 and 41 per cent respectively for irrigation water and fertilizer applied with trickle as compared to furrow irrigation. Trickle irrigated crops also showed a better response as regards the rate of survival, crop growth and time of maturity

  16. Newer Root Canal Irrigants in Horizon: A Review

    Directory of Open Access Journals (Sweden)

    Sushma Jaju

    2011-01-01

    Full Text Available Sodium hypochloride is the most commonly used endodontic irrigant, despite limitations. None of the presently available root canal irrigants satisfy the requirements of ideal root canal irrigant. Newer root canal irrigants are studied for potential replacement of sodium hypochloride. This article reviews the potential irrigants with their advantages and limitations with their future in endodontic irrigation.

  17. 21 CFR 876.5895 - Ostomy irrigator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ostomy irrigator. 876.5895 Section 876.5895 Food... DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5895 Ostomy irrigator. (a) Identification. An ostomy irrigator is a device that consists of a container for fluid, tubing with a cone-shaped...

  18. Weed Control with Cover Crops in Irrigated Potatoes

    OpenAIRE

    G.H. Mehring; J.E. Stenger; H.M. Hatterman-Valenti

    2016-01-01

    Field experiments at Oakes, ND, USA in 2010 and Carrington, ND, USA in 2011 were conducted to evaluate the potential for cover crops grown in the Northern Great Plains, USA in order to reduce weed emergence and density in irrigated potatoes. Treatments included five cover crop treatments and three cover crop termination treatments. Termination of cover crops was done with glyphosate, disk-till, and roto-till. Cover crop biomass accumulation was greatest for rye/canola and triticale at Oakes, ...

  19. Speed control variable rate irrigation

    Science.gov (United States)

    Speed control variable rate irrigation (VRI) is used to address within field variability by controlling a moving sprinkler’s travel speed to vary the application depth. Changes in speed are commonly practiced over areas that slope, pond or where soil texture is predominantly different. Dynamic presc...

  20. Position paper : Whole bowel irrigation

    NARCIS (Netherlands)

    2004-01-01

    Whole bowel irrigation (WBI) should not be used routinely in the management of the poisoned patient. Although some volunteer studies have shown substantial decreases in the bioavailability of ingested drugs, no controlled clinical trials have been performed and there is no conclusive evidence that

  1. Effects of irrigation, fertilization and drought on the occurrence of Lophodermium piceae in Picea abies needles

    Energy Technology Data Exchange (ETDEWEB)

    Lehtijaervi, Asko; Barklund, Pia [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Mycology and Pathology

    1999-08-01

    Effects of irrigation, drought and fertilization on the frequency of the fungal endophyte Lophodermium piceae in green needles was assessed in a 30-year-old experimental stand of Picea abies in southern Sweden. Frequencies of needles with L. piceae were lower in irrigation and ammonium sulphate fertilization treatments than in the control. Drought treatment frequencies were similar to the control. Needles were susceptible to colonization for at least 3 years; colonization increased with needle age. The results indicate that the increased availability of water to the root system as well as ammonium sulphate fertilization indirectly delays colonization of needles by L. piceae 21 refs, 3 figs, 2 tabs

  2. Winter wheat grain yield and its components in the North China Plain: irrigation management, cultivation, and climate

    Directory of Open Access Journals (Sweden)

    Lihua Lv

    2013-09-01

    Full Text Available Irrigation has been identified as the main driving factor of groundwater drawdown in the North China Plain (NCP. In order to develop appropriate irrigation strategies for satisfactory yields of wheat (Triticum aestivum L., grain yield (GY, yield components, and water use efficiency (WUE were studied. A field experiment was conducted with two types of winter wheat, 'Shimai15' and 'Shixin733', and five irrigation treatments, including rainfed and four spring irrigation water applications, in four growing seasons (2005 to 2009. Results showed that maximum GY was achieved with three irrigation treatments in the 2005-2006 and 2008-2009 dry seasons and two irrigation treatments in the 2006-2007 normal season. However, in the 2007-2008 wet season, the four irrigation treatments, especially the additional irrigation event at the reviving stage (28, produced maximum GY. Grain yield was significantly related to seasonal full evapotranspiration (ET and 410 to 530 mm of seasonal full ET, including 143 mm rainfall and 214 mm irrigation water, which led to maximum GY. The two types of cultivars responded differently to irrigation management in different rainfall years. The yield of the water-saving cv. 'Shimai 15' was much higher in the dry seasons than in the other seasons. Variations of yield components were mainly caused by irrigation time and meteorological factors. The higher accumulated temperature during the sowing and tillering stages (24 and irrigation or precipitation at the reviving stage (28 significantly improved tiller growth. The lower average temperature in March and April greatly increased grain number per spike. Sunshine duration played a decisive role in improving grain weight. Our results provide very useful information about irrigation time and frequency of winter wheat in the NCP in order to obtain high yield but reduce the use of underground water.

  3. A risk assessment framework for irrigated agriculture under climate change

    Science.gov (United States)

    Ronco, P.; Zennaro, F.; Torresan, S.; Critto, A.; Santini, M.; Trabucco, A.; Zollo, A. L.; Galluccio, G.; Marcomini, A.

    2017-12-01

    In several regions, but especially in semi-arid areas, raising frequency, duration and intensity of drought events, mainly driven by climate change dynamics, are expected to dramatically reduce the current stocks of freshwater resources, limiting crop development and yield especially where agriculture largely depends on irrigation. The achievement of an affordable and sustainable equilibrium between available water resources and irrigation demand is essentially related to the planning and implementation of evidence-based adaptation strategies and actions. The present study proposed a state-of-the art conceptual framework and computational methodology to assess the potential water scarcity risk, due to changes in climate trends and variability, on irrigated croplands. The model has been tested over the irrigated agriculture of Puglia Region, a semi-arid territory with the largest agricultural production in Southern Italy. The methodology, based on the Regional Risk Assessment (RRA) approach, has been applied within a scenario-based hazard framework. Regional climate projections, under alternative greenhouse gas concentration scenarios (RCP4.5 and RCP8.5) and for two different timeframes, 2021-2050 and 2041-2070 compared to the baseline 1976-2005 period, have been used to drive hydrological simulations of river inflow to the most important reservoirs serving irrigation purposes in Puglia. The novelty of the proposed RRA-based approach does not simply rely on the concept of risk as combination of hazard, exposure and vulnerability, but rather elaborates detailed (scientific and conceptual) framing and computational description of these factors, to produce risk spatial pattern maps and related statistics distinguishing the most critical areas (risk hot spots).. The application supported the identification of the most affected areas (i.e. Capitanata Reclamation Consortia under RCP8.5 2041-2070 scenario), crops (fruit trees and vineyards), and, finally, the vulnerability

  4. Remote Sensing of Irrigated Agriculture: Opportunities and Challenges

    Directory of Open Access Journals (Sweden)

    Chelsea Cervantes

    2010-09-01

    time and resources for ground-truthing. An additional challenge in mapping irrigation across large areas occurs in fragmented landscapes with small irrigated and cultivated fields, where the spatial scale of observations is pitted against the need for high frequency temporal acquisitions. Finally, this review identifies passive and active microwave observations, advanced image classification methods, and data fusion including optical and radar sensors or with information from sources with multiple spatial and temporal characteristics as key areas where additional research is needed.

  5. Root activity pattern of banana under irrigated and rain conditions

    International Nuclear Information System (INIS)

    Sobhana, A.; Aravindakshan, M.; Wahid, P.A.

    1989-01-01

    Root morphology by excavation method and root activity pattern by 32 P soil-injection technique have been studied in banana var., Nendran under rainfed/irrigated conditions. The number of roots, length and diameter of roots and dry weight of roots were found to be more for the rainfed banana crop compared to the irrigated. The results of the radiotracer studies indicated that about 60 per cent of the active roots of irrigated banana lie within 20 cm distance and about 90 per cent of the total root activity is found within 40 cm distance from the plant. In the case of rainfed crop about 85 per cent of the active roots were found within a radius of 40 cm around the plant. Active roots were found to be more concentrated at 15 to 30 cm depth under rainfed conditions while the density of active roots was more or less uniform along the profile upto a dpeth of 60 cm in irrigated banana. (author). 4 refs., 3 figs

  6. Low-frequency observations of Galactic supernova remnants and the distribution of low-density ionized gas in the interstellar medium

    International Nuclear Information System (INIS)

    Kassim, N.E.

    1989-01-01

    New long-wavelength observations of Galactic SNRs at 30.9 and 57.5 MHz are used to derive detailed low-frequency radio spectra for 32 SNRs. Of these, about two-thirds show turnovers at low frequencies, implying the presence of a widespread, but inhomogeneous, ionized absorbing medium along the lines of sight. These observations are combined with other low-frequency data to derive free-free optical depths toward 457 SNRs and to constrain the physical properties of the ionized gas responsible for the absorption. These optical depths are consistent with the expected absorbing properties of extended H II region envelopes. 43 refs

  7. Modernized Irrigation Technologies in West Africa

    Directory of Open Access Journals (Sweden)

    Hakan Büyükcangaz

    2017-12-01

    Full Text Available Crop production in West Africa is mostly dependent upon rainfed agriculture. Irrigation is a vital need due to uneven distribution of rainfall and seasonality of water resources. However, management and sustainability of irrigation are under risk due to notably weak database, excessive cost, unappropriate soil or land use, environmental problems and extreme pessimism in some quarters since rainfed agriculture is seen as potentially able to support the present population. This paper focuses on modernized irrigation technologies and systems that utilize less water. Information about irrigation systems in Ghana and Liberia were gathered through: 1 Irrigation development authorities in both countries, by reviewing past literatures, online publications, reports and files about irrigation in West Africa, specifically Ghana and Liberia; 2 International Food Policy Research Institute (IFPRI; 3 Collation of information, reports and data from Ghana Irrigation Development Authority (GIDA and 4 International Water Management Institute (IWMI. The result shows that both countries have higher irrigation potential. However, the areas developed for irrigation is still a small portion as compare to the total land available for irrigation. On the other hand, as seen in the result, Liberia as compare to Ghana has even low level of irrigation development.

  8. Modeling irrigation behavior in groundwater systems

    Science.gov (United States)

    Foster, Timothy; Brozović, Nicholas; Butler, Adrian P.

    2014-08-01

    Integrated hydro-economic models have been widely applied to water management problems in regions of intensive groundwater-fed irrigation. However, policy interpretations may be limited as most existing models do not explicitly consider two important aspects of observed irrigation decision making, namely the limits on instantaneous irrigation rates imposed by well yield and the intraseasonal structure of irrigation planning. We develop a new modeling approach for determining irrigation demand that is based on observed farmer behavior and captures the impacts on production and water use of both well yield and climate. Through a case study of irrigated corn production in the Texas High Plains region of the United States we predict optimal irrigation strategies under variable levels of groundwater supply, and assess the limits of existing models for predicting land and groundwater use decisions by farmers. Our results show that irrigation behavior exhibits complex nonlinear responses to changes in groundwater availability. Declining well yields induce large reductions in the optimal size of irrigated area and irrigation use as constraints on instantaneous application rates limit the ability to maintain sufficient soil moisture to avoid negative impacts on crop yield. We demonstrate that this important behavioral response to limited groundwater availability is not captured by existing modeling approaches, which therefore may be unreliable predictors of irrigation demand, agricultural profitability, and resilience to climate change and aquifer depletion.

  9. EnviroAtlas - Frequency and Density of Candidate Areas for Ecological Restoration by 12-digit HUC for the Conterminous United States

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset shows the number and density of candidate areas for ecological restoration in each 12-digit HUC. Ecological restoration may become a more...

  10. Morphogenetic, structural and productive traits of buffel grass under different irrigation regimes

    Directory of Open Access Journals (Sweden)

    Maria Janiele Ferreira Coutinho

    2015-06-01

    Full Text Available The water restriction conditions in the Brazilian semiarid region are one of the most limiting factors to the establishment and yield of forage grasses. This study aimed to evaluate the effect of different irrigation regimes on morphogenetic, structural and productive traits of buffel grass. Arandomized blocks design, with five treatments and six replications, was used. Treatments consisted of five irrigation regimes, corresponding to the intervals of 2, 4, 6, 8 and 10 days. The traits analyzed were: leaf emergence rate, phyllochron, leaf and stem elongation rate, leaf senescence rate, final leaf length, number of green leaves per tiller, number of tillers, stem height, leaf/stem ratio, leaf area index, dry mass of green leaf and stem, dry mass of green, dead and total forage, root dry mass, dry mass and green dry mass/dead dry mass ratio. The final leaf length and dead forage dry mass were not affected by the irrigation regimes. The leaf/stem ratio followed a quadratic model, maintaining the value of 0.51 up to the irrigation regime of four days. The other morphological, structural and productive traits decreased linearly with increasing irrigation frequencies. The irrigation intervals promoted reductions in the morphological, structural and productive parameters of buffel grass, when grown under greenhouse conditions. The irrigation regime of 2 days stands out as the least restrictive to the development of buffel grass.

  11. Phosphorus absorption in drip irrigation

    International Nuclear Information System (INIS)

    Guennelon, R.; Habib, R.

    1979-01-01

    Introducing the use of solute phosphate with drip irrigation may be an unsatisfying practice on account of the very weak mobility of PO 4 anion. Nevertheless P can move down to 30-40 cm depth by following the saturated flux along earth-worms holes or crakes, or by displacement in very narrow structural porosity, even in heavy soils. In this case roots cannot easily absorb PO 4 from soil solution, as soon as the soil is quite saturated. On the other hand, it seems that P absorption occurs very quickly and easily when the implantation of 32 P tagged solution is carried out at the border of zone which is concerned by the irrigation effects [fr

  12. Managing Water Resources for Environmentally Sustainable Irrigated Agriculture in Pakistan

    OpenAIRE

    Muhammad Afzal

    1996-01-01

    Pakistan’s agriculture is almost wholly dependent on irrigation and irrigated land supplies more than 90 percent of agricultural production. Irrigation is central to Pakistan’s economy. Massive investments in irrigation contributed to the development of one of the largest Indus Basin Irrigation System. Despite heavy budgetary inputs in irrigation system, it is facing shortage of resources and suffering from operational problems. The sustainability of irrigated agriculture is threatened due to...

  13. The Effect of Different Levels of Irrigation and Nitrogen Fertilizer on Yield and Water Use Efficiency of Potato in Subsurface Drip Irrigation

    Directory of Open Access Journals (Sweden)

    Mohammad Jolaini

    2017-06-01

    Full Text Available Introduction: After wheat, rice and corn, potato is the fourth most important food plant in the world. In comparison with other species, potato is very sensitive to water stress because of its shallow root system: approximately 85% of the root length is concentrated in the upper 0.3-0.4 m of the soil. Several studies showed that drip irrigation is an effective method for enhancing potato yield. Fabeiro et al. (2001 concluded that tuber bulking and ripening stages were found to be the most sensitive stages of water stress with drip irrigation. Water deficit occurring in these two growth stages could result in yield reductions. Wang et al. (2006 investigated the effects of drip irrigation frequency on soil wetting pattern and potato yield. The results indicated that potato roots were not limited in wetted soil volume even when the crop was irrigated at the highest frequency while high frequency irrigation enhanced potato tuber growth and water use efficiency (WUE. Though information about irrigation and N management of this crop is often conflicting in the literature, it is accepted generally that production and quality are highly influenced by both N and irrigation amounts and these requirements are related to the cropping technique. Researches revealed that nitrogen fertilizers play a special role in the growth, production and quality of potatoes. Materials and Methods: A factorial experiment in randomized complete block design with three replications was carried out during two growing seasons. Studied factors were irrigation frequency (I1:2 and I2:4 days interval and nitrogen fertilizer levels (applying 100 (N1, 75 (N2 and 50 (N3 % of the recommended amount. Nitrogen fertilizer was applied through irrigation water. In each plot two rows with within-and between-row spacing of 45 and 105 cm and 20 m length. The amount of nitrogen fertilizer for the control treatment was determined by soil analysis (N1. In all treatments, nitrogen fertilizer

  14. Changes in soil aggregate stability under different irrigation doses of waste water

    Science.gov (United States)

    Morugán, Alicia; García-Orenes, Fuensanta; Mataix-Solera, Jorge; Arcenegui, Victoria; Bárcenas, Gema

    2010-05-01

    Freshwater availability and soil degradation are two of the most important environmental problems in the Mediterranean area acerbated by incorrect agricultural use of irrigation in which organic matter is not correctly managed, the use of low quality water for irrigation, and the inefficiency of dose irrigation. For these reasons strategies for saving water and for the restoration of the mean properties of soil are necessary. The use of treated waste water for the irrigation of agricultural land could be a good solution to these problems, as it reduces the utilization of fresh water and could potentially improve key soil properties. In this work we have been studying, for more than three years, the effects on soil properties of different doses of irrigation with waste water. Here we show the results on aggregate stability. The study is located in an agricultural area at Biar (Alicante, SE of Spain), with a crop of grape (Vitis labrusca). Three types of waters are being used in the irrigation of the soil: fresh water (control) (TC), and treated waste water from secondary (T2) and tertiary treatment (T3). Three different doses of irrigation have been applied to fit the efficiency of the irrigation to the crop and soil type: D10 (10 L m-2 every week during 17 months), D50 (50 L m-2 every fifteen days during 14 moths) and D30 (30 L m-2 every week during 6 months up to present day). The results showed a clear decrease of aggregate stability during the period we used the second dose (D50) independent of the type of water used. That dose of irrigation and frequency produced strong wetting and drying cycles (WD) in the soil, and this is suspected to be the main factor responsible for the results. When we changed the dose of irrigation to D30, reducing the quantity per event and increasing the frequency, the soil aggregate stability started to improve. This dose avoids strong drying periods between irrigation events and the aggregate stability is confirmed to be slowly

  15. IRRIGATION OF ORNAMENTAL PLANT NURSERY

    Directory of Open Access Journals (Sweden)

    Eduardo de Aguiar do Couto

    2013-01-01

    Full Text Available Airports consume significant amounts of water which can be compared to the volume consumed by mid-size cities, thus practices aimed at reducing water consumption are important and necessar y. The objective of this study was to assess the reuse potential of sewage effluent produced at a mid-size international airport for nursery irri gation. The sewage treatment system consisted of a facultative pond followed by a constructed wetland, which were monitored during one hydrological year a nd the parameters COD, pH, solids, nitrogen, phosphorus and Escherichia coli we re analyzed. Removal efficiencies of 85% and 91% were achieved for C OD and solids, respectively. Removal efficiencies for ammonia nitrogen a nd total phosphorus were 77% and 59%, respectively. In terms of E. coli concen tration, the treated effluent met the recommendations by the World Health Organization for reuse in irrigation with the advantage of providing high levels of residual nutrient. The ornamental species Impatiens walleriana was irrigated with treated sewage effluent and plant growth characteristics were evalua ted. The experiment showed that reuse can enhance plant growth without signi ficantly affecting leaf tissue and soil characteristics. This study highlighted th e importance of simple technologies for sewage treatment especially in count ries which still do not present great investment in sanitation and proved that effluent reuse for landscape irrigation can provide great savings of water and financial resources for airport environments.

  16. Fruit yield and root system distribution of 'Tommy Atkins' mango under different irrigation regimes

    Directory of Open Access Journals (Sweden)

    Marcelo R. dos Santos

    2014-04-01

    Full Text Available This study aimed to evaluate the fruit yield and the distribution of 'Tommy Atkins' mango root system under different irrigation regimes in the semiarid region of Bahia. The experimental design was completely randomized with five treatments and three replicates: 1 - Irrigation supplying 100% of ETc in phases I, II and III; 2 - Regulated deficit irrigation (RDI supplying 50% of ETc in phase I (beginning of flowering to early fruit growth; 3 - RDI supplying 50% ETc in phase II (start of expansion until the beginning of physiological maturity; 4 - RDI supplying 50% ETc in phase III (physiological mature fruits; 5 - No irrigation during all three phases. The regulated deficit irrigation supplying 50% of the ETc during phase I and II provided larger root length density of 'Tommy Atkins' mango. Regardless of management strategy, the roots were developed in all evaluated soil volume and the highest density is concentrated from 0.50 to 1.50 m distance from the trunk and in 0.20 to 0.90 m depth in the soil, that suggests this region to be the best place for fertilizer application as well for soil water sensor placement. The application of RDI during fruit set does not influence either root distribution or production. Root system and crop production is significantly reduced under no irrigation conditions.

  17. An optimization model to design and manage subsurface drip irrigation system for alfalfa

    Science.gov (United States)

    Kandelous, M.; Kamai, T.; Vrugt, J. A.; Simunek, J.; Hanson, B.; Hopmans, J. W.

    2010-12-01

    Subsurface drip irrigation (SDI) is one of the most efficient and cost-effective methods for watering alfalfa plants. Lateral installation depth and distance, emitter discharge, and irrigation time and frequency of SDI, in addition to soil and climatic conditions affect alfalfa’s root water uptake and yield. Here we use a multi-objective optimization approach to find optimal SDI strategies. Our approach uses the AMALGAM evolutionary search method, in combination with the HYDRUS-2D unsaturated flow model to maximize water uptake by alfalfa’s plant roots, and minimize loss of irrigation and drainage water to the atmosphere or groundwater. We use a variety of different objective functions to analyze SDI. These criteria include the lateral installation depth and distance, the lateral discharge, irrigation duration, and irrigation frequency. Our framework includes explicit recognition of the soil moisture status during the simulation period to make sure that the top soil is dry for harvesting during the growing season. Initial results show a wide spectrum of optimized SDI strategies for different root distributions, soil textures and climate conditions. The developed tool should be useful in helping farmers optimize their irrigation strategy and design.

  18. Irrigation management strategies to improve Water Use Efficiency of potatoes crop in Central Tunisia

    Science.gov (United States)

    Ghazouani, Hiba; Provenzano, Giuseppe; Rallo, Giovanni; Mguidiche, Amel; Douh, Boutheina; Boujelben, Abdelhamid

    2015-04-01

    In Tunisia, the expansion of irrigated area and the semiarid climate make it compulsory to adopt strategies of water management to increase water use efficiency. Subsurface drip irrigation (SDI), providing the application of high frequency small irrigation volumes below the soil surface have been increasingly used to enhance irrigation efficiency. At the same time, deficit irrigation (DI) has shown successful results with a large number of crop in various countries. However, for some crops like potatoes, DI is difficult to manage due to the rapid effect of water stress on tuber yield. Irrigation frequency is a key factor to schedule subsurface drip irrigation because, even maintaining the total seasonal volume, soil wetting patterns can result different during the growth period, with consequence on crop yield. Despite the need to enhance water use efficiency, only a few studies related to deficit irrigation of horticultural crops have been made in Tunisia. Objective of the paper was to assess the effects of different on-farm irrigation strategies on water use efficiency of potatoes crop irrigated with subsurface drip irrigation in a semiarid area of central Tunisia. After validation, Hydrus-2D model was used to simulate soil water status in the root zone, to evaluate actual crop evapotranspiration and then to estimate indirectly water use efficiency (IWUE), defined as the ratio between crop yield and total amount of water supplied with irrigation. Field experiments, were carried out in Central Tunisia (10° 33' 47.0" E, 35° 58' 8.1° N, 19 m a.s.l) on a potatoes crop planted in a sandy loam soil, during the growing season 2014, from January 15 (plantation of tubers) to May 6 (harvesting). Soil water status was monitored in two plots (T1 and T2) maintained under the same management, but different irrigation volumes, provided by a SDI system. In particular, irrigation was scheduled according to the average water content measured in the root zone, with a total of 8

  19. Opportunities for Demand Response in California Agricultural Irrigation: A Scoping Study

    Energy Technology Data Exchange (ETDEWEB)

    Marks, Gary [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wilcox, Edmund [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Olsen, Daniel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Goli, Sasank [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-01-02

    California agricultural irrigation consumes more than ten billion kilowatt hours of electricity annually and has significant potential for contributing to a reduction of stress on the grid through demand response, permanent load shifting, and energy efficiency measures. To understand this potential, a scoping study was initiated for the purpose of determining the associated opportunities, potential, and adoption challenges in California agricultural irrigation. The primary research for this study was conducted in two ways. First, data was gathered and parsed from published sources that shed light on where the best opportunities for load shifting and demand response lie within the agricultural irrigation sector. Secondly, a small limited survey was conducted as informal face-to-face interviews with several different California growers to get an idea of their ability and willingness to participate in permanent load shifting and/or demand response programs. Analysis of the data obtained from published sources and the survey reveal demand response and permanent load shifting opportunities by growing region, irrigation source, irrigation method, grower size, and utility coverage. The study examines some solutions for demand response and permanent load shifting in agricultural irrigation, which include adequate irrigation system capacity, automatic controls, variable frequency drives, and the contribution from energy efficiency measures. The study further examines the potential and challenges for grower acceptance of demand response and permanent load shifting in California agricultural irrigation. As part of the examination, the study considers to what extent permanent load shifting, which is already somewhat accepted within the agricultural sector, mitigates the need or benefit of demand response for agricultural irrigation. Recommendations for further study include studies on how to gain grower acceptance of demand response as well as other related studies such as

  20. Rendimento da pupunheira em função da densidade de plantio, diâmetro de corte e manejo dos perfilhos no Vale do São Francisco Effect of density, cut-off diameter classes and shoot number on production and yield of irrigated plant peach palm at San Francisco River Valley

    Directory of Open Access Journals (Sweden)

    José Egidio Flori

    2004-02-01

    Full Text Available Com o objetivo de avaliar o rendimento de palmito de pupunheira irrigada em função da densidade de plantio, diâmetro de corte do estipe e o manejo dos perfilhos, instalou-se um experimento na Estação Experimental de Bebedouro da Embrapa Semi-Árido, Petrolina, PE. O delineamento utilizado foi de blocos ao acaso em parcelas subdivididas, sendo as parcelas constituídas por dois espaçamentos (2,0 x 1,0 m - E1 e 2,0 x 2,0 m - E2 e as subparcelas em arranjo fatorial 2 x 2, compreendendo dois manejos de perfilhos e duas classes de diâmetros de corte. As colheitas foram feitas a partir de 16 meses até os 69 meses após o plantio e realizadas com intervalos consecutivos de mais ou menos três meses. Pelos resultados, evidenciaram-se efeitos significativos para espaçamento, manejo de perfilhos e classe de diâmetro de corte. Não foram constatadas interações entre os tratamentos. Houve efeito significativo de espaçamento sobre o rendimento, diâmetro de corte, comprimento e peso médio do palmito. O rendimento e o peso do palmito da pupunheira foram de 545 e 434 kg ha-1 ano-1 e 147 g e 180 g nos espaçamentos E1 e E2, respectivamente. O diâmetro de corte afetou a altura da planta e peso médio do palmito. O manejo de perfilho afetou o rendimento e o peso médio do palmito, com 532 e 446 kg ha-1 e 177 e 149 g de palmito, respectivamente, no manejo de quatro e todos os perfilhos por planta. Pelos resultados, infere-se, como orientação técnica para os produtores de áreas irrigadas do Submédio São Francisco, o cultivo da pupunha no espaçamento de 2 m x 1 m, o manejo de quatro perfilhos por planta e o corte da planta com diâmetro variando de 10 a 12 cm, a 30 cm do nível do solo.The objective of this experiment was to evaluate the effect of planting density, cut-off diameter classes and shoot number on heart of palm production on irrigated peach palm. The experimental layout was a randomized split-plot design with a factorial arrangement

  1. Does colostomy irrigation affect functional outcomes and quality of life in persons with a colostomy?

    Science.gov (United States)

    Kent, Dea J; Long, Mary Arnold; Bauer, Carole

    2015-01-01

    Colostomy irrigation may be used by patients with colostomies to regulate bowel evacuations by stimulating emptying of the colon at regularly scheduled times. This Evidence-Based Report Card reviews the effect of colostomy irrigation on frequency of bowel evacuation, flatus production, odor, and health-related quality of life. We systematically reviewed the literature for studies that evaluated health-related quality of life in persons aged 18 years or older with colostomies of the sigmoid or descending left colon. A professional librarian performed the literature search, which yielded 499 articles using the search terms "colostomy," "colostomies," "therapeutic irrigation," "irrigation," and "irrigator." Following title and abstract reviews, we identified and retrieved 4 studies that met inclusion criteria. Colostomy irrigation reduces the frequency of bowel evacuations when compared to spontaneous evacuation and containment using a pouching system. Regular irrigation is associated with reductions in pouch usage. This change in bowel evacuation function frequently results in absence of bowel evacuations for 24 hours or longer, enabling some to discontinue ongoing use of a pouching system. Subjects using CI report reductions in flatus and odors associated with presence of a colostomy. One study was identified that found persons using CI reported higher health-related quality of life than did those who managed their colostomies with spontaneous evacuation using the Digestive Disease Quality of Life-15, but no differences were found when health-related quality of life was measured using the more generic instrument, the Medical Outcomes Study: Short Form-36. Instruction on principles and techniques of colostomy irrigation should be considered when managing patients with a permanent, left-sided colostomy.

  2. Substrates and irrigation levels for growing desert rose in pots

    Directory of Open Access Journals (Sweden)

    Ronan Carlos Colombo

    Full Text Available ABSTRACT In the past decades, desert rose has become a very popular ornamental plant, especially among collectors, due to its exotic and sculptural forms. However, it has been grown on a commercial scale only recently, and little is known about how to best manage it as a container-grown plant, or even which potting medium (substrate to recommend. Therefore, the aim of this study was to investigate the interactions between potting media and irrigation levels for growing desert rose as a potted ornamental plant. The experiment was conducted in a greenhouse using a 6 x 2 factorial arrangement with six replications, six potting media and two irrigation levels. The mixes were characterized by measuring their physical properties, specifically the density and water retention capacity (WRC, as well as chemical properties, such as the pH and electrical conductivity (EC. After 210 days, plant growth and plant water consumption were evaluated and measured. A lower dry density for the vermiculite mixes was observed in comparison to that for the sand mixes. However, WRC ranged from 428 to 528 mL L-1 among the mixes, values considered close to ideal. In general, plant growth exhibited higher increases in mixes consisting of coconut fiber + sand or vermiculite, regardless of the irrigation level. Mixes of vermiculite + coconut fiber and sand + coconut fiber can be used to grow desert rose in pots, as long as irrigation is used to maintain the moisture content of the potting medium (mix between 60-70% and 80-90% of the WRC.

  3. 75 FR 43958 - Turlock Irrigation District and Modesto Irrigation District; Notice of Application for Amendment...

    Science.gov (United States)

    2010-07-27

    ... to the Turlock Irrigation District's Tuolumne Substation; (2) 23-mile-long, 69-kV Don Pedro-Hawkins Line extending from the Don Pedro switchyard to the Turlock Irrigation District's Hawkins Substation...

  4. Effect of low-cost irrigation methods on microbial contamination of lettuce irrigated with untreated wastewater

    DEFF Research Database (Denmark)

    Keraita, Bernard; Konradsen, Flemming; Drechsel, P.

    2007-01-01

    OBJECTIVE: To assess the effectiveness of simple irrigation methods such as drip irrigation kits, furrow irrigation and use of watering cans in reducing contamination of lettuce irrigated with polluted water in urban farming in Ghana. METHODS: Trials on drip kits, furrow irrigation and watering...... cans were conducted with urban vegetable farmers. Trials were arranged in a completely randomised block design with each plot having all three irrigation methods tested. This was conducted in both dry and wet seasons. Three hundred and ninety-six lettuce, 72 soil, 15 poultry manure and 32 water samples...... were analysed for thermotolerant coliforms and helminth eggs. RESULTS: Lettuce irrigated with drip kits had the lowest levels of contamination, with, on average, 4 log units per 100 g, fewer thermotolerant coliforms than that irrigated with watering cans. However, drip kits often got clogged, required...

  5. Introduction: Panda or Hydra? The untold stories of drip irrigation

    NARCIS (Netherlands)

    Kuper, M.; Venot, J.P.; Zwarteveen, M.; Venot, J.P.; Kuper, M.; Zwarteveen, M.

    2017-01-01

    Irrigated areas in the world are witnessing a transformation from open canal systems to more ‘modern’ irrigation methods such as drip irrigation that convey water through closed pipe systems. Initially associated with hi-tech irrigated agriculture, drip irrigation is now being used by a wide range

  6. Saline water irrigation for crop production

    Energy Technology Data Exchange (ETDEWEB)

    Khan, A R [Directorate of Water Management Research, Indian Council of Agricultural Research (ICAR), Walmi Complex, P.O. - Phulwari Sharif, Patna (India); [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); Singh, S S; Singh, S R [Directorate of Water Management Research, Indian Council of Agricultural Research (ICAR), Walmi Complex, P.O. - Phulwari Sharif, Patna (India)

    2001-05-01

    Salinity is one of agriculture's most complex production problems. Excessive salts from irrigation water or high water tables can severely limit crop production. Years of saline water irrigation on poorly drained soils can eventually make economic crop production impossible. About 10% of all land are affected by salinity problems. They occur in every continent in different proportions, more frequently in arid and semi-arid areas. This paper discusses a range of problems related to use of saline water for crop irrigation.

  7. Saline water irrigation for crop production

    International Nuclear Information System (INIS)

    Khan, A.R.; Singh, S.S.; Singh, S.R.

    2001-05-01

    Salinity is one of agriculture's most complex production problems. Excessive salts from irrigation water or high water tables can severely limit crop production. Years of saline water irrigation on poorly drained soils can eventually make economic crop production impossible. About 10% of all land are affected by salinity problems. They occur in every continent in different proportions, more frequently in arid and semi-arid areas. This paper discusses a range of problems related to use of saline water for crop irrigation

  8. Senegal - Irrigation and Water Resource Management

    Data.gov (United States)

    Millennium Challenge Corporation — IMPAQ: This evaluation report presents findings from the baseline data collected for the Irrigation and Water Resources Management (IWRM) project, which serves as...

  9. Frequency and zero-point vibrational energy scale factors for double-hybrid density functionals (and other selected methods): can anharmonic force fields be avoided?

    Science.gov (United States)

    Kesharwani, Manoj K; Brauer, Brina; Martin, Jan M L

    2015-03-05

    We have obtained uniform frequency scaling factors λ(harm) (for harmonic frequencies), λ(fund) (for fundamentals), and λ(ZPVE) (for zero-point vibrational energies (ZPVEs)) for the Weigend-Ahlrichs and other selected basis sets for MP2, SCS-MP2, and a variety of DFT functionals including double hybrids. For selected levels of theory, we have also obtained scaling factors for true anharmonic fundamentals and ZPVEs obtained from quartic force fields. For harmonic frequencies, the double hybrids B2PLYP, B2GP-PLYP, and DSD-PBEP86 clearly yield the best performance at RMSD = 10-12 cm(-1) for def2-TZVP and larger basis sets, compared to 5 cm(-1) at the CCSD(T) basis set limit. For ZPVEs, again, the double hybrids are the best performers, reaching root-mean-square deviations (RMSDs) as low as 0.05 kcal/mol, but even mainstream functionals like B3LYP can get down to 0.10 kcal/mol. Explicitly anharmonic ZPVEs only are marginally more accurate. For fundamentals, however, simple uniform scaling is clearly inadequate.

  10. Role of sediment in the design and management of irrigation canals : Sunsari Morang Irrigation Scheme, Nepal

    NARCIS (Netherlands)

    Paudel, K.

    2010-01-01

    Sediment transport in irrigation canals The sediment transport aspect is a major factor in irrigation development as it determines to a large extent the sustainability of an irrigation scheme, particularly in case of unlined canals in alluvial soils. Investigations in this respect started since

  11. Automation of irrigation systems to control irrigation applications and crop water use efficiency

    Science.gov (United States)

    Agricultural irrigation management to slow water withdrawals from non-replenishing quality water resources is a global endeavor and vital to sustaining irrigated agriculture and dependent rural economies. Research in site-specific irrigation management has shown that water use efficiency, and crop p...

  12. Factors affecting irrigant extrusion during root canal irrigation: a systematic review

    NARCIS (Netherlands)

    Boutsioukis, C.; Psimma, Z.; van der Sluis, L.W.M.

    2013-01-01

    The aim of the present study was to conduct a systematic review and critical analysis of published data on irrigant extrusion to identify factors causing, affecting or predisposing to irrigant extrusion during root canal irrigation of human mature permanent teeth. An electronic search was conducted

  13. Irrigation as an Historical Climate Forcing

    Science.gov (United States)

    Cook, Benjamin I.; Shukla, Sonali P.; Puma, Michael J.; Nazarenko, Larissa S.

    2014-01-01

    Irrigation is the single largest anthropogenic water use, a modification of the land surface that significantly affects surface energy budgets, the water cycle, and climate. Irrigation, however, is typically not included in standard historical general circulation model (GCM) simulations along with other anthropogenic and natural forcings. To investigate the importance of irrigation as an anthropogenic climate forcing, we conduct two 5-member ensemble GCM experiments. Both are setup identical to the historical forced (anthropogenic plus natural) scenario used in version 5 of the Coupled Model Intercomparison Project, but in one experiment we also add water to the land surface using a dataset of historically estimated irrigation rates. Irrigation has a negligible effect on the global average radiative balance at the top of the atmosphere, but causes significant cooling of global average surface air temperatures over land and dampens regional warming trends. This cooling is regionally focused and is especially strong in Western North America, the Mediterranean, the Middle East, and Asia. Irrigation enhances cloud cover and precipitation in these same regions, except for summer in parts of Monsoon Asia, where irrigation causes a reduction in monsoon season precipitation. Irrigation cools the surface, reducing upward fluxes of longwave radiation (increasing net longwave), and increases cloud cover, enhancing shortwave reflection (reducing net shortwave). The relative magnitude of these two processes causes regional increases (northern India) or decreases (Central Asia, China) in energy availability at the surface and top of the atmosphere. Despite these changes in net radiation, however, climate responses are due primarily to larger magnitude shifts in the Bowen ratio from sensible to latent heating. Irrigation impacts on temperature, precipitation, and other climate variables are regionally significant, even while other anthropogenic forcings (anthropogenic aerosols

  14. improving of irrigation management: a learning based approach

    African Journals Online (AJOL)

    p2333147

    Irrigation farms are small businesses and like any other business, the managers or ... human factors and constraints that impact on the adoption of irrigation ... Informal interaction with other irrigation farmers and social networks played a ...

  15. Linear response at the 4-component relativistic density-functional level: application to the frequency-dependent dipole polarizability of Hg, AuH and PtH2

    International Nuclear Information System (INIS)

    Salek, Pawel; Helgaker, Trygve; Saue, Trond

    2005-01-01

    We report the implementation and application of linear response density-functional theory (DFT) based on the 4-component relativistic Dirac-Coulomb Hamiltonian. The theory is cast in the language of second quantization and is based on the quasienergy formalism (Floquet theory), replacing the initial state dependence of the Runge-Gross theorem by periodic boundary conditions. Contradictions in causality and symmetry of the time arguments are thereby avoided and the exchange-correlation potential and kernel can be expressed as functional derivatives of the quasienergy. We critically review the derivation of the quasienergy analogues of the Hohenberg-Kohn theorem and the Kohn-Sham formalism and discuss the nature of the quasienergy exchange-correlation functional. Structure is imposed on the response equations in terms of Hermiticity and time-reversal symmetry. It is observed that functionals of spin and current densities, corresponding to time-antisymmetric operators, contribute to frequency-dependent and not static electric properties. Physically, this follows from the fact that only a time-dependent electric field creates a magnetic field. It is furthermore observed that hybrid functionals enhance spin polarization since only exact exchange contributes to anti-Hermitian trial vectors. We apply 4-component relativistic linear response DFT to the calculation of the frequency-dependent polarizability of the isoelectronic series Hg, AuH and PtH 2 . Unlike for the molecules, the effect of electron correlation on the polarizability of the mercury atom is very large, about 25%. We observe a remarkable performance of the local-density approximation (LDA) functional in reproducing the experimental frequency-dependent polarizability of this atom, clearly superior to that of the BLYP and B3LYP functionals. This allows us to extract Cauchy moments (S(-4) = 382.82 and S(-6) = 6090.89 a.u.) that we believe are superior to experiment since we go to higher order in the Cauchy

  16. CRISS power spectral density

    International Nuclear Information System (INIS)

    Vaeth, W.

    1979-04-01

    The correlation of signal components at different frequencies like higher harmonics cannot be detected by a normal power spectral density measurement, since this technique correlates only components at the same frequency. This paper describes a special method for measuring the correlation of two signal components at different frequencies: the CRISS power spectral density. From this new function in frequency analysis, the correlation of two components can be determined quantitatively either they stem from one signal or from two diverse signals. The principle of the method, suitable for the higher harmonics of a signal as well as for any other frequency combinations is shown for the digital frequency analysis technique. Two examples of CRISS power spectral densities demonstrates the operation of the new method. (orig.) [de

  17. State updating of a distributed hydrological model with Ensemble Kalman Filtering: effects of updating frequency and observation network density on forecast accuracy

    Directory of Open Access Journals (Sweden)

    O. Rakovec

    2012-09-01

    Full Text Available This paper presents a study on the optimal setup for discharge assimilation within a spatially distributed hydrological model. The Ensemble Kalman filter (EnKF is employed to update the grid-based distributed states of such an hourly spatially distributed version of the HBV-96 model. By using a physically based model for the routing, the time delay and attenuation are modelled more realistically. The discharge and states at a given time step are assumed to be dependent on the previous time step only (Markov property.

    Synthetic and real world experiments are carried out for the Upper Ourthe (1600 km2, a relatively quickly responding catchment in the Belgian Ardennes. We assess the impact on the forecasted discharge of (1 various sets of the spatially distributed discharge gauges and (2 the filtering frequency. The results show that the hydrological forecast at the catchment outlet is improved by assimilating interior gauges. This augmentation of the observation vector improves the forecast more than increasing the updating frequency. In terms of the model states, the EnKF procedure is found to mainly change the pdfs of the two routing model storages, even when the uncertainty in the discharge simulations is smaller than the defined observation uncertainty.

  18. Green and blue water footprint reduction in irrigated agriculture: effect of irrigation techniques, irrigation strategies and mulching

    Science.gov (United States)

    Chukalla, A. D.; Krol, M. S.; Hoekstra, A. Y.

    2015-12-01

    Consumptive water footprint (WF) reduction in irrigated crop production is essential given the increasing competition for freshwater. This study explores the effect of three management practices on the soil water balance and plant growth, specifically on evapotranspiration (ET) and yield (Y) and thus the consumptive WF of crops (ET / Y). The management practices are four irrigation techniques (furrow, sprinkler, drip and subsurface drip (SSD)), four irrigation strategies (full (FI), deficit (DI), supplementary (SI) and no irrigation), and three mulching practices (no mulching, organic (OML) and synthetic (SML) mulching). Various cases were considered: arid, semi-arid, sub-humid and humid environments in Israel, Spain, Italy and the UK, respectively; wet, normal and dry years; three soil types (sand, sandy loam and silty clay loam); and three crops (maize, potato and tomato). The AquaCrop model and the global WF accounting standard were used to relate the management practices to effects on ET, Y and WF. For each management practice, the associated green, blue and total consumptive WF were compared to the reference case (furrow irrigation, full irrigation, no mulching). The average reduction in the consumptive WF is 8-10 % if we change from the reference to drip or SSD, 13 % when changing to OML, 17-18 % when moving to drip or SSD in combination with OML, and 28 % for drip or SSD in combination with SML. All before-mentioned reductions increase by one or a few per cent when moving from full to deficit irrigation. Reduction in overall consumptive WF always goes together with an increasing ratio of green to blue WF. The WF of growing a crop for a particular environment is smallest under DI, followed by FI, SI and rain-fed. Growing crops with sprinkler irrigation has the largest consumptive WF, followed by furrow, drip and SSD. Furrow irrigation has a smaller consumptive WF compared with sprinkler, even though the classical measure of "irrigation efficiency" for furrow

  19. On the interface trap density and series resistance of tin oxide film prepared on n-type Si (1 1 1) substrate: Frequency dependent effects before and after 60Co γ-ray irradiation

    International Nuclear Information System (INIS)

    Karadeniz, S.; Selcuk, A. Birkan; Tugluoglu, N.; Ocak, S. Bilge

    2007-01-01

    We report the first investigation of the frequency dependent effects of gamma irradiation on interface state density and series resistance determined from capacitance-voltage (C-V) and conductance-voltage (G-V) characteristics in SnO 2 /n-Si structures prepared by spray deposition method. The samples were irradiated using a 60 Co γ-ray source at 500 kGy at room temperature. The C-V and G-V measurements of the samples were performed in the voltage range -6 V to 2 V and at 10 kHz, 100 kHz, 500 kHz and 1 MHz at room temperature before and after 500 kGy irradiation. The measurement capacitance and conductance are corrected for series resistance. It has been seen that the value of the series resistance R s of sample decreases from 204 Ω to 55.4 Ω with increasing the frequency before irradiation while it decreases from 248 Ω to 60 Ω with increasing frequency at 500 kGy irradiation. It has been found that and D it values of MOS structure increases up to 100 kHz and then decreases up to 1 MHz while the R s increases with increasing irradiation dose for our sample. The interface state density D it ranges from 1.83 x 10 13 cm -2 eV -1 for before irradiation to 1.54 x 10 13 cm -2 eV -1 for 500 kGy irradiation dose at 500 kHz and decreases with increasing frequency

  20. Modelling human agency in ancient irrigation

    NARCIS (Netherlands)

    Ertsen, M.W.

    2011-01-01

    Human activity is key in understanding ancient irrigation systems. Results of short term actions build up over time, affecting civilizations on larger temporal and spatial scales. Irrigation systems, with their many entities, social and physical, their many interactions within a changing environment

  1. Technical efficiency of irrigated vegetable production among ...

    African Journals Online (AJOL)

    This study was carried out to analyse the technical efficiency of irrigated vegetable production among smallholder farmers in the guinea savannah, Nigeria, and determine the cost and returns on irrigated vegetable production. Two-stage sampling technique was used, purposive selection of two states and three Local ...

  2. Prospects and Constraints of Household Irrigation Practices ...

    African Journals Online (AJOL)

    Constraints and prospects of hand dug wells related to household irrigation were assessed in Hayelom watershed (~1045 ha), by evaluating groundwater suitability for irrigation, soil quality and impact of intervention. 181 hand dug wells have come into existence in the watershed due to intervention and benefiting about ...

  3. Using Automation to Improve Surface Irrigation Management

    Science.gov (United States)

    In the Lower Mississippi Water Resource Area (WRA 08), also called the Mid-South, 2 million ha of cropland (80% of the irrigated farmland) employ surface irrigation, almost equally divided between furrow (52%) and controlled flooding (48%). Because Mid-South farmers experience less-than-optimal surf...

  4. Syringe irrigation: blending endodontics and fluid dynamics

    NARCIS (Netherlands)

    Boutsioukis, C.; van der Sluis, L.W.M.; Basrani, B.

    2015-01-01

    Syringe irrigation remains a widely used irrigant delivery method during root canal treatment. An interdisciplinary approach involving well-established methods from the field of fluid dynamics can provide new insights into the mechanisms involved in cleaning and disinfection of the root canal system

  5. Syringe irrigation: blending endodontics and fluid dynamics

    NARCIS (Netherlands)

    Boutsioukis, Christos; van der Sluis, Lucas; Basrani, Bettina

    2015-01-01

    This book reviews the available information on bacterial disinfection in endodontics, with emphasis on the chemical treatment of root canals based on current understanding of the process of irrigation. It describes recent advances in knowledge of the chemistry associated with irrigants and delivery

  6. A scintigraphic study of colostomy irrigation

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Shinji; Fujii, Hisao; Nakano, Hiroshige (Nara Medical Univ., Kashihara (Japan))

    1991-09-01

    Colostomy irrigation was investigated by colonoscintigraphy. Twelve rectal cancer and one sigmoid colon cancer patients were examined. The tepid water whose volume was determined by barium enema was mixed with {sup 99m}Tc-DTPA. Dynamic scanning was started on commencement of colostomy irrigation. The sampling time was 3 seconds and scanning was performed for 30 minutes. The mean volume of remnant colon as measured by barium enema was 650 ml. The mean number of mass movements was 4.3. The mean evacuation time was 11 minutes 56 seconds and the mean half emptying time was calculated to be 9.5 minutes. The evacuation time in the patients who underwent colostomy irrigation for more than 2 years was greater than that in the patients who underwent irrigation for less than 2 years. Colonic motility was thought to have weakened. The half emptying time and the number of mass movements in the patients whose irrigation water went into the terminal ileum was more than that in the patients whose irrigation water was within the colon and cecum. Irrigation water which went into the terminal ileum was caused evacuation after the contents of the remnant colon were washed out. In conclusion, patients should have their colostomy irrigated with the tepid water, volume is determined by barium enema. Furthermore single infusion of the water is recommended. (author).

  7. A scintigraphic study of colostomy irrigation

    International Nuclear Information System (INIS)

    Yasuda, Shinji; Fujii, Hisao; Nakano, Hiroshige

    1991-01-01

    Colostomy irrigation was investigated by colonoscintigraphy. Twelve rectal cancer and one sigmoid colon cancer patients were examined. The tepid water whose volume was determined by barium enema was mixed with 99m Tc-DTPA. Dynamic scanning was started on commencement of colostomy irrigation. The sampling time was 3 seconds and scanning was performed for 30 minutes. The mean volume of remnant colon as measured by barium enema was 650 ml. The mean number of mass movements was 4.3. The mean evacuation time was 11 minutes 56 seconds and the mean half emptying time was calculated to be 9.5 minutes. The evacuation time in the patients who underwent colostomy irrigation for more than 2 years was greater than that in the patients who underwent irrigation for less than 2 years. Colonic motility was thought to have weakened. The half emptying time and the number of mass movements in the patients whose irrigation water went into the terminal ileum was more than that in the patients whose irrigation water was within the colon and cecum. Irrigation water which went into the terminal ileum was caused evacuation after the contents of the remnant colon were washed out. In conclusion, patients should have their colostomy irrigated with the tepid water, volume is determined by barium enema. Furthermore single infusion of the water is recommended. (author)

  8. Irrigation scheduling with the neutron probe

    International Nuclear Information System (INIS)

    Travers, P.

    1987-01-01

    The operational theory of the neutron probe is briefly outlined and its application and uses discussed in relation to determination of soil compaction and irrigation scheduling. Graphic examples are given of alluvial soil moisture profiles and how this information can be used to improve trickle irrigation in vineyards. 3 refs., 7 figs

  9. Review of ultrasonic irrigation in endodontics: increasing action of irrigating solutions

    Science.gov (United States)

    Mozo, Sandra; Llena, Carmen

    2012-01-01

    Introduction: Effective irrigant delivery and agitation are prerequisites for successful endodontic treatment. Ultrasonic irrigation can be performed with or without simultaneous ultrasonic instrumentation. Existing literature reveals that ultrasonic irrigation may have a very positive effect on chemical, biological and physical debridement of the root canal system as investigated in many in vitro studies. Objective: The purpose of this review article was to summarize and discuss the available information concerning ultrasonic irrigation in endodontics. Methods: This article presents an overview of ultrasonic irrigation methods and their debridement efficacy. In this paper the relevant literature on passive ultrasonic irrigation is reviewed. Information from original scientific papers or reviews listed in MEDLINE and Cochrane were included in the review. Results: The use of ultrasound in the irrigation procedure results in improved canal cleanliness, better irrigant transfer to the canal system, soft tissue debridement, and removal of smear layer and bacteria. There are many in vitro studies, but there is a need to standardize protocols, and correlate the clinical efficacy of ultrasonic devices with improved treatment outcomes. Understanding the basis of ultrasonic irrigation is fundamental for clinicians and researchers to improve the design and use of ultrasonic irrigation. Key words:Ultrasonic irrigation, ultrasound, smear layer, endodontics. PMID:22143738

  10. Survey of Endodontic Irrigants Used by Dentists With Varying Years of Professional Experience

    Directory of Open Access Journals (Sweden)

    Sharkov Nikolai

    2018-03-01

    Full Text Available Background/Aim: The aim of the present study was to describe the use of irrigants by dentists in Bulgaria in relation to their years of professional experience. Material and Methods: The data were collected with the help of a questionnaire. The survey included questions concerning frequency of irrigants applied, their respective concentrations, as well as spectrum of disinfectants used in endodontics. In addition, information about respondents’ age, years of professional experience, gender, and main areas of continuing education was collected. The statistical analysis was performed with the help of IBM SPSS Statistics 22.0. Results: 219 replies were analysed (response rate 27,3%. The majority of the respondents (31.1% had 21 to 30 years of professional experience. 18.7% had over 30 years. Most of the practitioners reported their continuing education to be in the area of general dentistry - 52%, while about 1.2 % had specialised in endodontics. Dentists with long-standing professional experience use predominantly H2O2 - 78%. Dentists with least experience use 17% EDTA - 53.6%. No significant differences were established for the use of sodium hypochlorite and 2% chlorhexidine. 82% of the respondents use conventional needle 27G for intracanal irrigation; 60% never use ultrasonic irrigation. Conclusions: The analysis of the usage of irrigants shows that many general dental practitioners do not follow the quality recommended protocols for endodontic irrigation protocols.

  11. Threats to rainfed and canal irrigated agro-ecosystems of the Punjab, Pakistan by weed infestation

    International Nuclear Information System (INIS)

    Hussain, M.; Ahmed, M.S.A.; Hameed, M.; Aqeel, M.

    2012-01-01

    To record the weed flora infesting the rainfed and canal irrigated arable fields in the Punjab province, three districts viz. Chakwal, Jhelum and Rawalpindi in rainfed agro-ecosystem, while three districts in canal irrigated wheat fields i.e., Sahiwal, Qasoor and Gujrat were surveyed comprehensively to examine weed spectra. Weeds occurring in various localities largely varied with the variation in the mode of irrigation i.e., Barani areas and Canal irrigated area. In Rainfed (Barani) areas Fumeria parviflora and Asphodelus tenuifolius were noted frequently while their representation was very rare or even absent in canal irrigated areas. Carthamus oxayacantha was also observed at some sites there. The only weeds growing infrequently were hardy grasses like Cynodon dactylon and Cyperus rotundus. None of the weed could cross the limits of occasional frequency level. Nevertheless, in canal irrigated areas Convolvulus arvensis, Anagalus arvensis, Chenopodium sp., Melilotus alba, Lepidium sativum, Lathyrus aphaca, Medicago denticulata, Rumex dentatus and Cynodon dactylon were frequently observed. Phalaris minor and Avena fatua formed very dense stands in many areas. Carthamus oxayacantha, Poa annua, Sonchus asper and Vicia sativa were recorded infrequently. The farmers of Sahiwal and Qasoor districts seem well informed about the importance and use of weedicides as a result the spectrum of weeds growing there was quite low and none of them could establish dense stands. (author)

  12. [Irrigants and intracanal medicaments in endodontics].

    Science.gov (United States)

    Zehnder, Matthias; Lehnert, Birgit; Schönenberger, Kathrin; Waltimo, Tuomas

    2003-01-01

    Modern, biologic root canal therapy should be performed with suitable irrigating solutions and intracanal medicaments. The goal of endodontic treatment is to free the treated tooth from infection and prevent reinfection as thoroughly as possible by means which do not put the organism at risk. In this review of the literature, an evidence-based concept for irrigation and medication of root canal systems is presented. Irrigants and medicaments are discussed with respect to their antimicrobial, tissue-dissolving and endotoxin-decontaminating capacity in relation to their systemic toxicity. Recent findings pertaining to interactions of root canal medicaments and irrigating solutions and their impact on a sound irrigating and medicating concept are discussed.

  13. Effect of organic matter, irrigation and soil mulching on the nutritional ...

    African Journals Online (AJOL)

    Rukevwe S. Abraka

    2016-11-30

    Nov 30, 2016 ... necessary for the soil humidity to be in an adequate amount (Danso ... clay, with soil and particle density of: 1.51 and 2.76 g cm-3, respectively ..... fertilization and irrigation methods on nitrogen uptake, intercepted ŷ = 2373.4 + ...

  14. Mapping soil moisture across an irrigated field using electromagnetic conductivity imaging

    Science.gov (United States)

    The ability to measure and map volumetric soil water theta quickly and accurately is important in irrigated agriculture. However, the traditional approach of using thermogravimetric moisture (w) and converting this to theta using measurements of bulk density (theta – cm3/cm3) is laborious and time c...

  15. Are existing irrigation salinity leaching requirement guidelines overly conservative or obsolete?

    Science.gov (United States)

    Water scarcity and increased frequency of drought, resulting from erratic weather attributable to climatic change or alterations in historical weather patterns, have caused greater scrutiny of irrigated agriculture’s demand on water resources. The traditional guidelines for the calculation of the c...

  16. Scheduling of Irrigation and Leaching Requirements

    Directory of Open Access Journals (Sweden)

    Amer Hassan Al-haddad

    2015-03-01

    Full Text Available Iraq depends mainly on Tigris and Euphrates Rivers to provide high percentage of agricultural water use for thousands years. At last years, Iraq is suffering from shortage in water resources due to global climate changes and unfair water politics of the neighboring countries, which affected the future of agriculture plans for irrigation, added to that the lack of developed systems of water management in the irrigation projects and improper allocation of irrigation water, which reduces water use efficiency and lead to losing irrigation water and decreasing in agricultural yield. This study aims at studying the usability of irrigation and leaching scheduling within the irrigating projects and putting a complete annual or seasonal irrigation program as a solution for the scarcity of irrigation water, the increase of irrigation efficiency, lessening the salinity in the projects and preparing an integral irrigation calendar through field measurements of soil physical properties and chemical for project selected and compared to the results of the irrigation scheduling and leaching with what is proposed by the designers. The process is accomplished by using a computer program which was designed by Water Resources Department at the University of Baghdad, with some modification to generalize it and made it applicable to various climatic zone and different soil types. Study area represented by large project located at the Tigris River, and this project was (Al-Amara irrigation project. Sufficient samples of project's soil were collected so as to identify soil physical and chemical properties and the salinity of soil and water as well as identifying the agrarian cycles virtually applied to this project. Finally, a comparison was conducted between the calculated water quantities and the suggested ones by the designers. The research results showed that using this kind of scheduling (previously prepared irrigation and leaching scheduling with its properties

  17. Optimization of modern irrigation for biosaline agriculture

    International Nuclear Information System (INIS)

    Shahid, S.A.; Hasbini, B.

    2007-01-01

    Supplementation water is a must to offset the water requirement to produce profitable crops in most arid and semiarid zones, where fresh water resources are insufficient to meet the pressure of irrigated agriculture. This necessitates the use of poor quality water resources. These waters if not properly managed and used can cause serious soil related problems (salinity, sodicity, destruction of soil structure) in addition to decline in crop yields. Biosaline agriculture (using saline water on saline soils to grow salt-tolerant crops) becomes the only option for the farmer when both soil and water resources are saline and the water resource is scarce. In this regards key design considerations must be taken into account when irrigating with salty waters to optimize water uses and to reduce subsequent soil salinity development. Sprinkler irrigation systems are commonly used in irrigation of large-scale irrigational production systems. However they tend to concentrate salts on the leaves of plants. For this reason discharge and degree of overlap between consecutive sprinkler heads, are key design parameters when applying salty waters. Trickle irrigation is the most efficient system and is gaining importance in the GCC countries in the agriculture and landscape irrigation. The objective of this study was to optimize modern irrigation systems through development of design standards for drip (emitters spacing) and sprinkler irrigation systems (single head jet and overlapping) by applying saline water. The effect of emitter spacing (drip) and overlapping (sprinkler) were tested for the formation of salt contours in soil. The leaching ratio (LR) is the overall soil sanity within rhizosphere divided by the average irrigation water salinity. In this study LR is used to evaluate the effectiveness of irrigation systems in developing soil sanity. From the present investigations it is concluded that when using saline water for irrigation, the soil sanity development can be

  18. Analysis of Fluctuations of Electron Density in the D-region During the 2017 Solar Eclipse using a Very Low Frequency Receiver

    Science.gov (United States)

    Hernandez, E.; Mathur, S.; Fenton, A.; Behrend, C. C.; Bering, E., III

    2017-12-01

    As part of the Undergraduate Student Instrumentation Project (USIP) at the University of Houston, multiple Very Low Frequency (VLF) Radio Receivers will be set up during the 2017 solar eclipse. They will be taking data from Omaha, Nebraska and Casper, Wyoming. The receiver, using an air loop antenna, will record magnetic field fluctuations caused by VLF waves. The purpose of this experiment is to study the effects of the sudden change in electromagnetic radiation from the sun on the D-region of the ionosphere. VLF waves were chosen for measurement because naturally occurring VLF waves propagate through the Earth-ionosphere waveguide, which can be used to remotely observe the ionosphere. The D-region reduces the energy in propagating waves due to absorption. This means that any fluctuations in the D-region are inversely correlated to the strength of VLF waves being received. The experiment will focus on receiving waves transmitted from specific stations that are on the other side of totality. The amplitude and phase of the received waves will be measured and analyzed. It is hoped that this experiment will help us gain a better understanding of VLFs from the D-region during the solar eclipse, as well as increasing the overall data available for use by the community.

  19. Nucleus management with irrigating vectis

    Directory of Open Access Journals (Sweden)

    Srinivasan Aravind

    2009-01-01

    Full Text Available The main objective in modern cataract surgery is to achieve a better unaided visual acuity with rapid post-surgical recovery and minimal surgery-related complications. Early visual rehabilitation and better unaided vision can be achieved only by reducing the incision size. In manual small incision cataract surgery (MSICS, incision is between 5.5 to 7 mm. Once the nucleus is prolapsed into the anterior chamber, it can be extracted through the tunnel. Nucleus extraction with an irrigating vectis is a very simple technique, which combines mechanical and hydrostatic forces to express out the nucleus. This technique is time-tested with good results and more than 95% of nuclei in MSICS are extracted in this way offering all the merits of phacoemulsification with the added benefits of having wider applicability, better safety, shorter learning curve and lower cost.

  20. The Temporal Variation of Leaf Water Potential in Pistachio under Irrigated and Non-Irrigated Conditions

    Directory of Open Access Journals (Sweden)

    Yusuf AYDIN

    2014-09-01

    Full Text Available The present study was carried out in the experimental field of Pistachio Research Institute on pistachio trees which has uzun variety that was 30 years old. The aim of this research was to determine the Leaf Water Potential (LWP of Pistacia vera L. under irrigated and non-irrigated conditions. In the study, the leaf water potential of pistachio was investigated under fully irrigated and non irrigated conditions. The leaf water potential values were measured one day before and after irrigation by using pressure chamber technique at the beginning, mid and end of irrigation season. According to the results obtained from measurements, the LWP value at the beginning of the irrigation season was -3.7 MPa at noon time due to relatively high temperature for both treatments. At the time of pre-dawn and sunset, this value increased and reached to - 1.6 MPa due to relatively low temperature. In general, the LWP values during the mid of irrigation season, in the irrigated treatments, reached to almost -2.5 MPa in the non-irrigated treatment and the value was measured as -3.68 MPa.

  1. Biological degradation of chernozems under irrigation

    Directory of Open Access Journals (Sweden)

    Oksana Naydyonova

    2014-12-01

    Full Text Available We studied the changes in the state of microbial cenosis of Ukraine’s chernozems under irrigation. Considerable part of Ukraine’s chernozems is located in the areas where humidification is insufficient and unstable. Irrigation is a soil-reclamation measure for chernozems of Ukrainian Forest-steppe and Steppe which enables getting the assured yield, especially vegetable and fodder crops. At the same time, irrigation is a powerful anthropogenic factor that affects the soil, causes a significant transformation of many of its properties and regimes including biological ones. Often these changes are negative. The purpose of our investigation was to identify changes in the state of microbial cenoses of chernozem soils under irrigation which depend on such factors as the quality of irrigation water, the duration and intensity of irrigation, the initial properties of soil, the structure of crop rotation, usage of fertilizing systems and agroameliorative techniques. We identified direction and evaluated a degree of changes in biological properties of chernozems under influence of irrigation in different agro-irrigational and soil-climatic conditions. In the long-term stationary field experiments we identified the following biological indices of irrigated soils and their non-irrigated analogues: a number of microorganisms which belong to main ecological-trophic groups, activity of soil enzymes (dehydrogenase, invertase, phenol oxidase, soil phytotoxic activity, cellulose destroying capacity of soil, indices of oligotrophy and mineralization, summary biological index (SBI and index of biological degradation (BDI. Results of researches showed that irrigation unbalanced the soil ecosystem and stipulated the forming of microbial cenosis with new parameters. Long-term intensive irrigation of typical chernozem (Kharkiv Region with fresh water under condition of 4-fields vegetable crop rotation led to the degradation changes of its microbial cenosis such as

  2. Frequency of Osteoporosis and Osteopenia According To Bone Mineral Density of Proximal Femur Subregions in Normal and Osteopenic Postmenopausal Women With Respect to Total Hip Bone

    Directory of Open Access Journals (Sweden)

    Murat Ersöz

    2002-09-01

    Full Text Available In this study 29 normal (mean age: 65.6 ± 5.1 years and 33 osteopenic (mean age: 67.6 ± 4.9 years postmenopausal women according to total bone mineral density (BMD of the hip were evaluated for BMD values of subregions of proximal femur. The percentages for osteoporosis and osteopenia with respect to subregions were 13.8% and 58.6% for femoral neck and 20.7% and 41.4% for Ward’s triangle in normal group. In trochanteric and intertrochanteric measurements there were no T scores below –2.5 but 17.2% of the subjects were osteopenic with regard to trochanteric and 6.9% were osteopenic due to intertrochanteric BMD values. The percentages for osteoporosis and osteopenia with respect to subregion measurements were 57.6% and 42.4% for femoral neck, 60.6% and 36.4% for Ward’s triangle, 3% and 78.8% for trochanteric, 9.1% and 87.9% for intertrochanteric regions in osteopenic group according to total hip values. Knowing that hip fracture risk is increasing 2-3 fold for 1 standart deviation decrease from the young adult mean value for all subregions and knowing the relation between cervical hip fractures and BMD values of Ward’s triangle and femoral neck and the relation between intertrochanteric fractures and trochanteric BMD values, it is recommended to evaluate the BMD values of subregions of the hip besides the total hip values in daily practice.

  3. Irrigation Water Management in Latin America

    Directory of Open Access Journals (Sweden)

    Aureo S de Oliveira

    2009-12-01

    Full Text Available Latin American countries show a great potential for expanding their irrigated areas. Irrigation is important for strengthening local and regional economy and for enhancing food security. The present paper aimed at providing a brief review on key aspects of irrigation management in Latin America. Poor irrigation management can have great impact on crop production and on environment while good management reduces the waste of soil and water and help farmers maximizing their profits. It was found that additional research is needed to allow a better understanding of crop water requirements under Latin American conditions as well as to provide farmers with local derived information for irrigation scheduling. The advantages of deficit irrigation practices and the present and future opportunities with the application of remote sensing tools for water management were also considered. It is clear that due to the importance of irrigated agriculture, collaborative work among Latin American researchers and institutions is of paramount importance to face the challenges imposed by a growing population, environment degradation, and competition in the global market.

  4. Ancestral irrigation method by kanis in Bolivia

    Science.gov (United States)

    Roldán-Cañas, José; Chipana, René; Fátima Moreno-Pérez, María

    2015-04-01

    Irrigation in the Andean region is an ancient practice. For centuries, farmers were able to use the waters of rivers, lakes and springs to complement or supplement the scarce rainfall regime. The inter-Andean valleys of the Department of La Paz are the best areas for the study of traditional irrigation systems. This work has been carried out in the community of Jatichulaya located in te town of Charazani, 300 km from the city of La Paz, which lies 3250 meters above sea level. The annual rainfall ranges around 450 mm distributed mainly between the months of December to March. Therefore, water is needed to achieve adequate crop yields. The traditional irrigation system is done by the method of Kanis, consisting of a surface irrigation already developed by traditional Andean cultures of the country, in harmony with the ecological and productive characteristics of the area. Water enters the irrigation plot through a main channel (mama kani) from which the secondary channels (juchuy kanis) are derived. The fundamental characteristic of this irrigation is that these channels are open at the same time the water enters into the plot. The system works properly, adapting to the topography of the area. The irrigation method practiced in this community does not cause water erosion of soils because water management within the plot is based on the ancient knowledge of farmers following the contour lines. This practice allows good irrigation development and soil protection without causing any problems. However, it was evident a high use of labor in irrigation practice. Irrigation scheduling is done according to requests made by the irrigators in a given period. Delivering of water to the farmers is made by the so-called Water Agent (Agente de Aguas) or person in charge of the distribution of water. The Water Agent is elected annually and its functions include the maintenance and care of all system waterworks. The period between August and January is the highest water demand and

  5. Seasonal population dynamics of Homalodisca vitripennis (Hemiptera: Cicadellidae) in sweet orange trees maintained under continuous deficit irrigation.

    Science.gov (United States)

    Krugner, Rodrigo; Groves, Russell L; Johnson, Marshall W; Flores, Arnel P; Hagler, James R; Morse, Joseph G

    2009-06-01

    A 2-yr study was conducted in a citrus orchard (Citrus sinensis L. Osbeck cultivar Valencia) to determine the influence of plant water stress on the population dynamics of glassy-winged sharpshooter, Homalodisca vitripennis (Germar). Experimental treatments included irrigation at 100% of the crop evapotranspiration rate (ET(c)) and continuous deficit-irrigation regimens at 80 and 60% ET(c). Microclimate and plant conditions monitored included temperature and humidity in the tree canopy, leaf surface temperature, water potential, and fruit quality and yield. Glassy-winged sharpshooter population densities and activity were monitored weekly by a combination of visual inspections, beat net sampling, and trapping. Glassy-winged sharpshooter populations were negatively affected by severe plant water stress; however, population densities were not linearly related to decreasing water availability in plants. Citrus trees irrigated at 60% ET(c) had significantly warmer leaves, lower xylem water potential, and consequently hosted fewer glassy-winged sharpshooter eggs, nymphs, and adults than trees irrigated at 80% ET(c). Citrus trees irrigated at 100% ET(c) hosted similar numbers of glassy-winged sharpshooter stages as trees irrigated at 60% ET(c) and a lower number of glassy-winged sharpshooter nymphs than the 80% ET(c) treatment, specifically during the nymphal density peak in mid-April to early July. Irrigation treatments did not affect populations of monitored natural enemies. Although the adult glassy-winged sharpshooter population was reduced, on average, by 50% in trees under severe water stress, the total number of fruit and number of fruit across several fruit grade categories were significantly lower in the 60% ET(c) than in the 80 and 100% ET(c) irrigation treatments.

  6. Irrigation water sources and irrigation application methods used by U.S. plant nursery producers

    Science.gov (United States)

    Paudel, Krishna P.; Pandit, Mahesh; Hinson, Roger

    2016-02-01

    We examine irrigation water sources and irrigation methods used by U.S. nursery plant producers using nested multinomial fractional regression models. We use data collected from the National Nursery Survey (2009) to identify effects of different firm and sales characteristics on the fraction of water sources and irrigation methods used. We find that regions, sales of plants types, farm income, and farm age have significant roles in what water source is used. Given the fraction of alternative water sources used, results indicated that use of computer, annual sales, region, and the number of IPM practices adopted play an important role in the choice of irrigation method. Based on the findings from this study, government can provide subsidies to nursery producers in water deficit regions to adopt drip irrigation method or use recycled water or combination of both. Additionally, encouraging farmers to adopt IPM may enhance the use of drip irrigation and recycled water in nursery plant production.

  7. Water distribution in an orchard irrigated by perforated distributors in stony ground

    International Nuclear Information System (INIS)

    Decroix, M.; Marcesse, J.; Normand, M.

    1975-01-01

    In the context of new irrigation techniques the Compagnie Nationale d'Amenagement du Bas-Rhone et du Languedoc (B.Rh.L.) has developed a process of localized irrigation by perforated distributors. Conditions were defined for the optimum use of this process, especially the distribution of water in the ground. The study was carried out in a peach orchard in stony ground. The neutronic method was used to measure the soil moisture content. Because of the heterogeneous stone size distribution it was necessary for the specific humidity determination to take into account the dry apparent density. This parameter was measured by gammametry [fr

  8. effect of deficit irrigation on growth and yield of okro

    African Journals Online (AJOL)

    User

    reduce the demand for irrigation water (Boland et al., 1993). Deficit irrigation is another way in which water use efficiency can be maximized for higher yields per unit of irrigation water. Stegman (1982) reported that the yield of maize, sprinkler irrigated to induce a 30 - 40 percent depletion of available water between.

  9. Using container weights to determine irrigation needs: A simple method

    Science.gov (United States)

    R. Kasten Dumroese; Mark E. Montville; Jeremiah R. Pinto

    2015-01-01

    Proper irrigation can reduce water use, water waste, and incidence of disease. Knowing when to irrigate plants in container nurseries can be determined by weighing containers. This simple method is quantifiable, which is a benefit when more than one worker is responsible for irrigation. Irrigation is necessary when the container weighs some target as a proportion of...

  10. Local land-atmosphere feedbacks limit irrigation demand

    Science.gov (United States)

    Decker, Mark; Ma, Shaoxiu; Pitman, Andy

    2017-05-01

    Irrigation is known to influence regional climate but most studies forecast and simulate irrigation with offline (i.e. land only) models. Using south eastern Australia as a test bed, we demonstrate that irrigation demand is fundamentally different between land only and land-atmosphere simulations. While irrigation only has a small impact on maximum temperature, the semi-arid environment experiences near surface moistening in coupled simulations over the irrigated regions, a feedback that is prevented in offline simulations. In land only simulations that neglect the local feedbacks, the simulated irrigation demand is 25% higher and the standard deviation of the mean irrigation rate is 60% smaller. These local-scale irrigation-driven feedbacks are not resolved in coarse-resolution climate models implying that use of these tools will overestimate irrigation demand. Future studies of irrigation demand must therefore account for the local land-atmosphere interactions by using coupled frameworks, at a spatial resolution that captures the key feedbacks.

  11. Analysis of Irrigation Water Quality at Kadawa Irrigation Project for Improved Productivity

    Directory of Open Access Journals (Sweden)

    AR Sanda

    2014-09-01

    Full Text Available In the face of water scarcity and the several negative consequences, such as water wastage, flooding, water logging, soil losses and production losses, conserving the finite amount of fresh water is a must. The quality of irrigation water must therefore be ascertained. The chemical quality of three sources of irrigation water from canal and drainage water, namely drainage water, fresh irrigation water from canal, and drainage/irrigation water mixture, were analyzed from Kadawa irrigation Project for year 2013 and 2014 cropping seasons, with the view to evaluating the potential risks associated with their use in irrigation and hence their suitability or otherwise for irrigation purposes. The analysis revealed that the use of drainage water alone for irrigation may result in problems associated with salinity, while a blend of drainage/irrigation water in the ratio of 1:1 is a viable means of water conservation and a good means of crop production. DOI: http://dx.doi.org/10.3126/ije.v3i3.11082 International Journal of Environment Vol.3(3 2014: 235-240

  12. 16. PRE-OPERATIVE BLADDER IRRIGATION

    African Journals Online (AJOL)

    Esem

    effectiveness of using preoperative bladder irrigation with 1% povidone iodine in reducing ... consenting patient who presented to the department of surgery for open ..... infections in a tertiary care center in south-western. Nigeria. International ...

  13. Deciphering groundwater quality for irrigation and domestic

    Indian Academy of Sciences (India)

    Groundwater quality; irrigation and domestic suitability; ionic balance, Suri I and II ... is important for groundwater planning and management in the study area. ... total hardness (TH), Piper's trilinear diagram and water quality index study.

  14. Parasitological Contamination of Wastewater Irrigated and Raw ...

    African Journals Online (AJOL)

    Tadesse

    Occurrence of infective stages of intestinal parasites on wastewater- irrigated vegetables ..... reported the health hazards of agricultural reuse of untreated wastewater through detection of .... State of knowledge in land treatment of wastewater.

  15. Theoretical interpretations and experimental verifications of a radioelectric resonance method for measuring the electronic density and collision frequency in a discharge plasma in gases; Interpretations theoriques et verifications experimentales d'une methode de resonance radioelectrique pour la mesure de la densite d'une decharge dans les gaz

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen Trong, Khoi [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    Theoretical discussions and experimental verifications of one radioelectric resonance method for measuring plasma electronic density and collision frequency. (author) [French] Discussions theoriques et verifications experimentales sur une methode de resonance radioelectrique pour la mesure de la densite electronique et de la frequence de collision d'un plasma d'une decharge dans le gaz. (auteur)

  16. An improved delivery system for bladder irrigation.

    Science.gov (United States)

    Moslemi, Mohammad K; Rajaei, Mojtaba

    2010-10-05

    Occasionally, urologists may see patients requiring temporary bladder irrigation at hospitals without stocks of specialist irrigation apparatus. One option is to transfer the patient to a urology ward, but often there are outstanding medical issues that require continued specialist input. Here, we describe an improved system for delivering temporary bladder irrigation by utilizing readily available components and the novel modification of a sphygmomanometer blub. This option is good for bladder irrigation in patients with moderate or severe gross hematuria due to various causes. In this prospective study from March 2007 to April 2009, we used our new system in eligible cases. In this system, an irrigant bag with 1 L of normal saline was suspended 80 cm above the indwelled 3-way Foley catheter, and its drainage tube was inserted into the irrigant port of the catheter. To increase the flow rate of the irrigant system, we inserted a traditional sphygmomanometer bulb at the top of the irrigant bag. This closed system was used for continuous bladder irrigation (CBI) in patients who underwent open prostatectomy, transurethral resection of the prostate (TURP), or transurethral resection of the bladder (TURB). This high-pressure system is also used for irrigation during cystourethroscopy, internal urethrotomy, and transurethral lithotripsy. Our 831 eligible cases were divided into two groups: group 1 were endourologic cases and group 2 were open prostatectomy, TURP, and TURB cases. The maximum and average flow rates were evaluated. The efficacy of our new system was compared prospectively with the previous traditional system used in 545 cases. In group 1, we had clear vision at the time of endourologic procedures. The success rate of this system was 99.5%. In group 2, the incidence of clot retention decreased two fold in comparison to traditional gravity-dependent bladder flow system. These changes were statistically significant (P = 0.001). We did not observe any adverse

  17. Evaluation of Modern Irrigation Techniques with Brackish Water

    OpenAIRE

    Aboulila, Tarek Selim

    2012-01-01

    Modern irrigation techniques are becoming increasingly important in water-scarce countries especially in arid and semiarid regions. Higher crop production and better water use efficiency are usually achieved by drip irrigation as compared to other irrigation methods. Furthermore, by using drip irrigation simultaneously with brackish irrigation water, some of the water stress due to shortage of fresh water resources can be managed. The objective of the current study was to investigate the infl...

  18. Decision support system for surface irrigation design

    OpenAIRE

    Gonçalves, José M.; Pereira, L.S.

    2009-01-01

    The SADREG decision support system was developed to help decision makers in the process of design and selection of farm surface irrigation systems to respond to requirements of modernization of surface irrigation—furrow, basin, and border irrigation. It includes a database, simulation models, user-friendly interfaces, and multicriteria analysis models. SADREG is comprised of two components: design and selection. The first component applies database information, and through several si...

  19. System contemplations for precision irrigation in agriculture

    Science.gov (United States)

    Schubert, Martin J. W.

    2017-04-01

    This communication contemplates political, biological and technical aspects for efficient and profitable irrigation in sustainable agriculture. A standard for irrigation components is proposed. The need for many, and three-dimensionally distributed, soil measurement points is explained, thus enabling the control of humidity in selected layers of earth. Combined wireless and wired data transmission is proposed. Energy harvesting and storage together with mechanical sensor construction are discussed.

  20. Management of poor quality irrigation water

    International Nuclear Information System (INIS)

    Change, M.H.; Leghari, A.M.; Sipio, Q.A.

    2000-01-01

    The effect of poor quality drainage effluent on moderately saline sodic, medium textured soil at different growth stages of wheat and cotton is reported. The irrigation treatments were: I) All canal irrigations, II) one irrigation of 75 mm with saline drainage effluent (EC = 3 dS m1) after four weeks sowing of the crop, III) one irrigation of 75 mm with saline drainage effluent after seven weeks sowing of the crop, and IV) one irrigation of 75 mm with saline drainage effluent after ten weeks sowing of the crop. The treatments receiving saline water gave significant decrease in crop yields as compared to canal irrigation treatment. The higher yield of wheat and seed cotton was recorded T1 followed by T2, T3 and T4. The trend of produce was T1< T2< T3< T4 respectively. Electrical conductivity of the soil (Ece) in T1 was decreased and in other three treatments was increased, whereas, pH decreased in T1 and T2. The SAR of soil decreased in all the treatments as compared with initial values. Treatment receiving an irrigation with saline water after four weeks of sowing (T2) was better in reducing soil salinity as compared to treatments receiving such water after 7 or 10 weeks os sowing. Poor quality water (EC = 3 d Sm/sup -1/) can be managed for irrigation after four weeks of swing of crops provided certain soil and water management practices like good seed bed preparation and proper drainage measures are adopted. (author)

  1. Effects of climate change on water abstraction restrictions for irrigation during droughts - The UK case

    Science.gov (United States)

    Rey Vicario, D.; Holman, I.

    2016-12-01

    The use of water for irrigation and on-farm reservoir filling is globally important for agricultural production. In humid climates, like the UK, supplemental irrigation can be critical to buffer the effects of rainfall variability and to achieve high quality crops. Given regulatory efforts to secure sufficient environmental river flows and meet rising water demands due to population growth and climate change, increasing water scarcity is likely to compound the drought challenges faced by irrigated agriculture in this region. Currently, water abstraction from surface waters for agricultural irrigation can be restricted by the Environment Agency during droughts under Section 57 of the Water Resources Act (1991), based on abnormally low river flow levels and rainfall forecast, causing significant economic impacts on irrigated agricultural production. The aim of this study is to assess the impact that climate change may have on agricultural abstraction in the UK within the context of the abstraction restriction triggers currently in place. These triggers have been applied to the `Future Flows hydrology' database to assess the likelihood of increasing restrictions on agricultural abstraction in the future by comparing the probability of voluntary and compulsory restrictions in the baseline (1961-1990) and future period (2071-2098) for 282 catchments throughout the whole of the UK. The results of this study show a general increase in the probability of future agricultural irrigation abstraction restrictions in the UK in the summer, particularly in the South West, although there is significant variability between the 11 ensemble members. The results also indicate that UK winters are likely to become wetter in the future, although in some catchments the probability of abstraction restriction in the reservoir refilling winter months (November-February) could increase slightly. An increasing frequency of drought events due to climate change is therefore likely to lead to

  2. Grower demand for sensor-controlled irrigation

    Science.gov (United States)

    Lichtenberg, Erik; Majsztrik, John; Saavoss, Monica

    2015-01-01

    Water scarcity is likely to increase in the coming years, making improvements in irrigation efficiency increasingly important. An emerging technology that promises to increase irrigation efficiency substantially is a wireless irrigation sensor network that uploads sensor data into irrigation management software, creating an integrated system that allows real-time monitoring and control of moisture status that has been shown in experimental settings to reduce irrigation costs, lower plant loss rates, shorten production times, decrease pesticide application, and increase yield, quality, and profit. We use an original survey to investigate likely initial acceptance, ceiling adoption rates, and profitability of this new sensor network technology in the nursery and greenhouse industry. We find that adoption rates for a base system and demand for expansion components are decreasing in price, as expected. The price elasticity of the probability of adoption suggests that sensor networks are likely to diffuse at a rate somewhat greater than that of drip irrigation. Adoption rates for a base system and demand for expansion components are increasing in specialization in ornamental production: growers earning greater shares of revenue from greenhouse and nursery operations are willing to pay more for a base system and are willing to purchase larger numbers of expansion components at any given price. We estimate that growers who are willing to purchase a sensor network expect investment in this technology to generate significant profit, consistent with findings from experimental studies.

  3. Revisiting colostomy irrigation: a viable option for persons with permanent descending and sigmoid colostomies.

    Science.gov (United States)

    Kent, Dea J; Arnold Long, Mary; Bauer, Carole

    2015-01-01

    Colostomy irrigation (CI) is the regular irrigation of the bowel for persons with a permanent colostomy of the descending or sigmoid colon. Although this technique was first described in the 1920s, a recent study of 985 WOC nurses found that almost half (47%) do not routinely teach CI to persons with colostomies. In a systematic review (Evidence-Based Report Card) published in this issue of the Journal, we summarized current best evidence concerning the effect of CI on bowel function and found that irrigation reduces the frequency of bowel elimination episodes and allows some patients to reduce or eliminate ongoing use of a pouching system. This article describes techniques for teaching CI and discussed additional findings associated with CI.

  4. Laser frequency modulation with electron plasma

    Science.gov (United States)

    Burgess, T. J.; Latorre, V. R.

    1972-01-01

    When laser beam passes through electron plasma its frequency shifts by amount proportional to plasma density. This density varies with modulating signal resulting in corresponding modulation of laser beam frequency. Necessary apparatus is relatively inexpensive since crystals are not required.

  5. Irrigated Agriculture in Morocco: An Agent-Based Model of Adaptation and Decision Making Amid Increasingly Frequent Drought Events

    Science.gov (United States)

    Norton, M.

    2015-12-01

    In the past 100 years, Morocco has undertaken a heavy investment in developing water infrastructure that has led to a dramatic expansion of irrigated agriculture. Irrigated agriculture is the primary user of water in many arid countries, often accounting for 80-90% of total water usage. Irrigation is adopted by farmers not only because it leads to increased production, but also because it improves resilience to an uncertain climate. However, the Mediterranean region as a whole has also seen an increase in the frequency and severity of drought events. These droughts have had a dramatic impact on farmer livelihoods and have led to a number of coping strategies, including the adoption or disadoption of irrigation. In this study, we use a record of the annual extent of irrigated agriculture in Morocco to model the effect of drought on the extent of irrigated agriculture. Using an agent-based socioeconomic model, we seek to answer the following questions: 1) Do farmers expand irrigated agriculture in response to droughts? 2) Do drought events entail the removal of perennial crops like orchards? 3) Can we detect the retreat of irrigated agriculture in the more fragile watersheds of Morocco? Understanding the determinants of irrigated crop expansion and contractions will help us understand how agro-ecological systems transition from 20th century paradigms of expansion of water supply to a 21st century paradigm of water use efficiency. The answers will become important as countries learn how to manage water in new climate regimes characterized by less reliable and available precipitation.

  6. Performing drip irrigation by the farmer managed Seguia Khrichfa irrigation system, Morocco

    NARCIS (Netherlands)

    Kooij, van der S.

    2016-01-01

    Drip irrigation is represented in literature and agricultural policies as a modern and water saving technology. Because this technology is often associated with ‘modern’ agriculture and development, it seems out-of-place in ‘traditional’ farmer managed irrigation systems (FMIS). Thinking along

  7. Chemical colostomy irrigation with glyceryl trinitrate solution.

    Science.gov (United States)

    O'Bichere, A; Bossom, C; Gangoli, S; Green, C; Phillips, R K

    2001-09-01

    Colostomy irrigation may improve patient quality of life, but is time consuming. This study tests the hypothesis that irrigation with glyceryl trinitrate solution, by inducing gastrointestinal smooth muscle relaxation, may accelerate expulsion of stool by passive emptying, thereby reducing irrigation time. Fifteen colostomy irrigators(with more than 3 years' experience) performed washout with tap water compared with water containing 0.025 mg/kg glyceryl trinitrate. Fluid inflow time, total washout time, and hemodynamic changes occurring during glyceryl trinitrate irrigation were documented by an independent observer. Subjects recorded episodes of fecal leakage and overall satisfaction on a visual analog scale. Cramps, headaches, and whether or not a stoma bag was used were expressed as a percentage of number of irrigations. Comparison of fluid inflow time, total washout time, leakage, and satisfaction was by Wilcoxon's signed-rank test and headaches, cramps, and stoma bag use was by McNemar's test. Pulse rate (paired t-test), systolic and diastolic blood pressures (Wilcoxon's test) at 20 and 240 minutes after washout with glyceryl trinitrate solution were compared with baseline. Fifteen patients (9 female), with a mean age of 53 (31-73) years, provided 30 sessions (15 with water and 15 with glyceryl trinitrate). Medians (interquartile ranges) for water vs. glyceryl trinitrate were fluid inflow time 7 (4-10) vs. 4, (3-5; P = 0.001); total washout time 40 (30-55) vs. 21, (15-24; P colostomy irrigation time compared with the generally recommended tap water. Patients suffer fewer leakages and are highly satisfied, but side effects are potential drawbacks. Other colonoplegic agent solutions should now be evaluated.

  8. Irrigation Analysis Based on Long-Term Weather Data

    Directory of Open Access Journals (Sweden)

    James R. Mahan

    2016-08-01

    Full Text Available Irrigation management is based upon delivery of water to a crop in the correct amount and time, and the crop’s water need is determined by calculating evapotranspiration (ET using weather data. In 1994, an ET-network was established in the Texas High Plains to manage irrigation on a regional scale. Though producers used the ET-network, by 2010 public access was discontinued. Why did producers allow a valuable irrigation-management tool to be eliminated? Our objective was to analyze the effect of declining well capacities on the usefulness of cotton ET (ETc for irrigation. Thirty years (1975–2004 of daily ETc data were used to compare irrigation demand vs. irrigation responses at four locations, analyzed for multiple years and range of well capacities for three irrigation-intervals. Results indicated that when well capacities declined to the point that over-irrigation was not possible, the lower well capacities reduced the value of ETc in terms of the number of irrigations and total amount of water applied. At well capacities <1514 L·min−1 the fraction of irrigations for which ETc information was used to determine the irrigation amount was <35% across years and irrigation intervals. The value of an ETc-based irrigation may fall into disuse when irrigation-water supplies decline.

  9. Real-time drought forecasting system for irrigation managment

    Science.gov (United States)

    Ceppi, Alessandro; Ravazzani, Giovanni; Corbari, Chiara; Masseroni, Daniele; Meucci, Stefania; Pala, Francesca; Salerno, Raffaele; Meazza, Giuseppe; Chiesa, Marco; Mancini, Marco

    2013-04-01

    In recent years frequent periods of water scarcity have enhanced the need to use water more carefully, even in in European areas traditionally rich of water such as the Po Valley. In dry periods, the problem of water shortage can be enhanced by conflictual use of water such as irrigation, industrial and power production (hydroelectric and thermoelectric). Further, over the last decade the social perspective on this issue is increasing due to climate change and global warming scenarios which come out from the last IPCC Report. The increased frequency of dry periods has stimulated the improvement of irrigation and water management. In this study we show the development and implementation of the real-time drought forecasting system Pre.G.I., an Italian acronym that stands for "Hydro-Meteorological forecast for irrigation management". The system is based on ensemble prediction at long range (30 days) with hydrological simulation of water balance to forecast the soil water content in every parcel over the Consorzio Muzza basin. The studied area covers 74,000 ha in the middle of the Po Valley, near the city of Lodi. The hydrological ensemble forecasts are based on 20 meteorological members of the non-hydrostatic WRF model with 30 days as lead-time, provided by Epson Meteo Centre, while the hydrological model used to generate the soil moisture and water table simulations is the rainfall-runoff distributed FEST-WB model, developed at Politecnico di Milano. The hydrological model was validated against measurements of latent heat flux and soil moisture acquired by an eddy-covariance station. Reliability of the forecasting system and its benefits was assessed on some cases-study occurred in the recent years.

  10. Irrigation Training Manual. Planning, Design, Operation, and Management of Small-Scale Irrigation Systems [and] Irrigation Reference Manual. A Technical Reference to Be Used with the Peace Corps Irrigation Training Manual T0076 in the Selection, Planning, Design, Operation, and Management of Small-Scale Irrigation Systems.

    Science.gov (United States)

    Salazar, LeRoy; And Others

    This resource for trainers involved in irrigated agriculture training for Peace Corps volunteers consists of two parts: irrigation training manual and irrigation reference manual. The complete course should fully prepare volunteers serving as irrigation, specialists to plan, implement, evaluate and manage small-scale irrigation projects in arid,…

  11. The effect of irrigation time and type of irrigation fluid on cartilage surface friction.

    Science.gov (United States)

    Stärke, F; Awiszus, F; Lohmann, C H; Stärke, C

    2018-01-01

    It is known that fluid irrigation used during arthroscopic procedures causes a wash-out of lubricating substances from the articular cartilage surface and leads to increased friction. It was the goal of this study to investigate whether this effect depends on the time of irrigation and type of fluid used. Rabbit hind legs were used for the tests. The knees were dissected and the friction coefficient of the femoral cartilage measured against glass in a boundary lubrication state. To determine the influence of irrigation time and fluid, groups of 12 knees received either no irrigation (control), 15, 60 or 120min of irrigation with lactated Ringer's solution or 60min of irrigation with normal saline or a sorbitol/mannitol solution. The time of irrigation had a significant effect on the static and kinetic coefficient of friction (CoF), as had the type of fluid. Longer irrigation time with Ringer's solution was associated with increased friction coefficients (relative increase of the kinetic CoF compared to the control after 15, 60 and 120min: 16%, 76% and 88% respectively). The sorbitol/mannitol solution affected the static and kinetic CoF significantly less than either Ringer's or normal saline. The washout of lubricating glycoproteins from the cartilage surface and the associated increase of friction can be effectively influenced by controlling the time of irrigation and type of fluid used. The time of exposure to the irrigation fluid should be as short as possible and monosaccharide solutions might offer a benefit compared to salt solutions in terms of the resultant friction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Carbon and water footprints of irrigated corn and non-irrigated wheat in Northeast Spain.

    Science.gov (United States)

    Abrahão, Raphael; Carvalho, Monica; Causapé, Jesús

    2017-02-01

    Irrigation increases yields and allows several crops to be produced in regions where it would be naturally impossible due to limited rainfall. However, irrigation can cause several negative environmental impacts, and it is important to understand these in depth for the correct application of mitigation measures. The life cycle assessment methodology was applied herein to compare the main irrigated and non-irrigated crops in Northeast Spain (corn and wheat, respectively), identifying those processes with greater contribution to environmental impacts (carbon and water footprint categories) and providing scientifically-sound information to facilitate government decisions. Due to concerns about climate change and water availability, the methods selected for evaluation of environmental impacts were IPCC 2013 GWP (carbon footprint) and water scarcity indicator (water footprint). The area studied, a 7.38-km 2 basin, was monitored for 12 years, including the period before, during, and after the implementation of irrigation. The functional unit, to which all material and energy flows were associated with, was the cultivation of 1 ha, throughout 1 year. The overall carbon footprint for irrigated corn was higher, but when considering the higher productivity achieved with irrigation, the emissions per kilogram of corn decrease and finally favor this irrigated crop. When considering the water footprint, the volumes of irrigation water applied were so high that productivity could not compensate for the negative impacts associated with water use in the case of corn. Nevertheless, consideration of productivities and gross incomes brings the results closer. Fertilizer use (carbon footprint) and irrigation water (water footprint) were the main contributors to the negative impacts detected.

  13. Municipal Treated Wastewater Irrigation: Microbiological Risk Evaluation

    Directory of Open Access Journals (Sweden)

    Antonio Lonigro

    2008-06-01

    Full Text Available Municipal wastewater for irrigation, though treated, can contain substances and pathogens toxic for humans and animals. Pathogens, although not harmful from an agronomical aspect, undoubtedly represent a major concern with regards to sanitary and hygienic profile. In fact, vegetable crops irrigated with treated wastewater exalt the risk of infection since these products can also be eaten raw, as well as transformed or cooked. Practically, the evaluation of the microbiological risk is important to verify if the microbial limits imposed by law for treated municipal wastewater for irrigation, are valid, thus justifying the treatments costs, or if they are too low and, therefore, they don’ t justify them. Different probabilistic models have been studied to assess the microbiological risk; among these, the Beta-Poisson model resulted the most reliable. Thus, the Dipartimento di Scienze delle Produzioni Vegetali of the University of Bari, which has been carrying out researches on irrigation with municipal filtered wastewater for several years, considered interesting to verify if the microbial limits imposed by the italian law n.185/03 are too severe, estimating the biological risk by the probabilistic Beta-Poisson model. Results of field trials on vegetable crops irrigated by municipal filtered wastewater, processed by the Beta-Poisson model, show that the probability to get infection and/or illness is extremely low, and that the actual italian microbial limits are excessively restrictive.

  14. Automated Irrigation System for Greenhouse Monitoring

    Science.gov (United States)

    Sivagami, A.; Hareeshvare, U.; Maheshwar, S.; Venkatachalapathy, V. S. K.

    2018-06-01

    The continuous requirement for the food needs the rapid improvement in food production technology. The economy of food production is mainly dependent on agriculture and the weather conditions, which are isotropic and thus we are not able to utilize the whole agricultural resources. The main reason is the deficiency of rainfall and paucity in land reservoir water. The continuous withdrawal water from the ground reduces the water level resulting in most of the land to come under the arid. In the field of cultivation, use of appropriate method of irrigation plays a vital role. Drip irrigation is a renowned methodology which is very economical and proficient. When the conventional drip irrigation system is followed, the farmer has to tag along the irrigation timetable, which is different for diverse crops. The current work makes the drip irrigation system an automated one, thereby the farmer doesn't want to follow any timetable since the sensor senses the soil moisture content and based on it supplies the water. Moreover the practice of economical sensors and the simple circuitry makes this project as an inexpensive product, which can be bought even by an underprivileged farmer. The current project is best suited for places where water is limited and has to be used in limited quantity.

  15. Automated Irrigation System for Greenhouse Monitoring

    Science.gov (United States)

    Sivagami, A.; Hareeshvare, U.; Maheshwar, S.; Venkatachalapathy, V. S. K.

    2018-03-01

    The continuous requirement for the food needs the rapid improvement in food production technology. The economy of food production is mainly dependent on agriculture and the weather conditions, which are isotropic and thus we are not able to utilize the whole agricultural resources. The main reason is the deficiency of rainfall and paucity in land reservoir water. The continuous withdrawal water from the ground reduces the water level resulting in most of the land to come under the arid. In the field of cultivation, use of appropriate method of irrigation plays a vital role. Drip irrigation is a renowned methodology which is very economical and proficient. When the conventional drip irrigation system is followed, the farmer has to tag along the irrigation timetable, which is different for diverse crops. The current work makes the drip irrigation system an automated one, thereby the farmer doesn't want to follow any timetable since the sensor senses the soil moisture content and based on it supplies the water. Moreover the practice of economical sensors and the simple circuitry makes this project as an inexpensive product, which can be bought even by an underprivileged farmer. The current project is best suited for places where water is limited and has to be used in limited quantity.

  16. When should irrigators invest in more water-efficient technologies as an adaptation to climate change?

    Science.gov (United States)

    Malek, K.; Adam, J. C.; Stockle, C.; Brady, M.; Yoder, J.

    2015-12-01

    climate change could justify the investment in new irrigation systems during this century, but the timing of a farmer's response is likely to depend on a variety of factors, including changes in the frequency and magnitude of drought events, current irrigation systems, climatological characteristics within the basin, and crop type.

  17. Management Strategies to Sustain Irrigated Agriculture with Combination of Remote Sensing, Weather Monitoring & Forecasting and SWAP Modeling

    Science.gov (United States)

    Ermolaeva, Olga; Zeyliger, Anatoly

    2017-04-01

    Today world's water systems face formidable threats due to climate change and increasing water withdraw for agriculture, industry and domestic use. Projected in many parts of the earth increases in temperature, evaporation, and drought frequency shrunk water availability and magnify water scarcity. Declining irrigation water supplies threaten the sustainability of irrigated agricultural production which plays a critical role in meeting global food needs. In irrigated agriculture there is a strong call for deep efforts in order on the one hand to improve water efficiency use and on the other to maximize yields. The aim of this research is to provide tool to optimize water application with crop irrigation by sprinkling in order to sustain irrigated agriculture under limited water supply by increasing net returns per unit of water. For this aim some field experimental results of 2012 year growing season of alfalfa, corn and soya irrigated by sprinkling machines crops at left bank of Volga River at Saratov Region of Russia. Additionally a combination of data sets was used which includes MODIS images, local meteorological station and results of SWAP (Soil-Water-Atmosphere-Plant) modeling. This combination was used to estimate crop water stress defined as ratio between actual (ETa) and potential (ETc) evapotranspiration. By this way it was determined the effect of applied irrigation scheduling and water application depths on evapotranspiration, crop productivity and water stress coefficient. Aggregation of actual values of crop water stress and biomass data predicted by SWAP agrohydrological model with weather forecasting and irrigation scheduling was used to indicate of both rational timing and amount of irrigation water allocation. This type of analysis facilitating an efficient water management can be extended to irrigated areas by developing maps of water efficiency application serving as an irrigation advice system for farmers at his fields and as a decision support

  18. Weed Control with Cover Crops in Irrigated Potatoes

    Directory of Open Access Journals (Sweden)

    G.H. Mehring

    2016-01-01

    Full Text Available Field experiments at Oakes, ND, USA in 2010 and Carrington, ND, USA in 2011 were conducted to evaluate the potential for cover crops grown in the Northern Great Plains, USA in order to reduce weed emergence and density in irrigated potatoes. Treatments included five cover crop treatments and three cover crop termination treatments. Termination of cover crops was done with glyphosate, disk-till, and roto-till. Cover crop biomass accumulation was greatest for rye/canola and triticale at Oakes, and hairy vetch and hairy vetch/rye at Carrington. Cover crop and termination affected weed control 14, 29, and 51 days after planting (DAP at Oakes. Weed control at Carrington was at least 90% for all cover crop and termination treatments at all three evaluation timings. Marketable yield at Oakes was greater when roto-till was used to terminate the cover crops compared with disk-till or herbicide, which is beneficial for organic systems where herbicides are not used. Marketable yield at Carrington was not affected by cover crop or termination treatments. Results suggest that cover crops can successfully be integrated into irrigated potato production for weed control with yields equal to no cover crop, and with attention to potential mechanical difficulties.

  19. Evaluation of the effects of mulch on optimum sowing date and irrigation management of zero till wheat in central Punjab, India using APSIM.

    Science.gov (United States)

    Balwinder-Singh; Humphreys, E; Gaydon, D S; Eberbach, P L

    2016-10-01

    loam soil. There was little effect of mulch on irrigation requirement for late October sowings. There were large trade-offs between irrigation input, yield, WP ET and WP I on the sandy loam with regard to the optimum irrigation schedule. Maximum yield occurred with very frequent irrigation (10-20% SWD) which also had the greatest irrigation input, while WP I was highest with least frequent irrigation (70% SWD), and WP ET was highest with irrigation at 40-50% SWD. This was the case with and without mulch. On the clay loam, the trade-offs were not so pronounced, as maximum yield was reached with irrigation at 50% SWD, with and without mulch. However, both WP ET and WP I were maximum and irrigation input least at the lowest irrigation frequency (70% SWD). On both soils, maximum yield, WP ET and WP I were higher with mulch, while irrigation input was slightly lower, but mulch had very little effect on the irrigation thresholds at which each parameter was maximised.

  20. Isotonic saline nasal irrigation in clinical practice: a literature review

    Directory of Open Access Journals (Sweden)

    Sabrina Costa Lima

    Full Text Available Abstract Introduction: Nasal instillation of saline solution has been used as part of the treatment of patients with upper respiratory tract diseases. Despite its use for a number of years, factors such as the amount of saline solution to be used, degree of salinity, method and frequency of application have yet to be fully explained. Objective: Review the reported outcomes of saline nasal irrigation in adults with allergic rhinitis, acute or chronic sinusitis and after functional endoscopic sinus surgery (FESS, and provide evidence to assist physiotherapists in decision making in clinical practice. Methods: A search was conducted of the Pubmed and Cochrane Library databases between 2007 and 2014. A combination of the following descriptors was used as a search strategy: nasal irrigation, nasal lavage, rhinitis, sinusitis, saline, saline solution. Results: Eight clinical trials were included, analyzed according to participant diagnosis. Conclusion: The evidence found was heterogeneous, but contributed to elucidating uncertainties regarding the use of nasal lavage in the clinical practice of physical therapy, such as the protocols used.

  1. Effect of Timing and Amount of Irrigation Water on Bean Yield and Water Use Efficiency in Arid and Semi-arid Conditions

    Directory of Open Access Journals (Sweden)

    S.S. Nurbakhsh

    2016-02-01

    consumption was affected by irrigation time. Among full irrigation treatments, irrigation at 2 p.m. and 6 a.m. had the highest and lowest water consumption, respectively. The total amount of water used in irrigation at 8 a.m., 2:00 p.m. and 6 p.m. compared to 6:00 a.m. was increased by1.6, 9.5 and 4.1 percent, respectively. The results showed that irrigation at 2:00 p.m., caused a significant reduction in yield. Moreover, water use efficiency in 6 a.m. treatments had increased 18.5 percent more than that of the 2:00 p.m. irrigation treatment. The time of irrigation did not have a meaningful effect on bush height, the number of minor branches, the pod's length. The effect of the amount of irrigation water was meaningful on bush height, number of minor branches, seeds yield, the number of pods in the bush, pods length and seed weight. Seed yield at 8:00 a.m., 2:00 p.m. and 6:00 p.m. treatments has shown 0.29, 17.1 and 7.6 percent decrease in comparison with 6:00 a.m. irrigation treatment, respectively. Moreover, 100-seed weights were significantly affected by the irrigation time. The maximum and minimum weights of 100-seed weights were obtained at 6:00 a.m. and 6:00 p.m. irrigation, respectively. Analysis of variance showed that the number of pods per plant was affected by irrigation time. The maximum number of pods per plant was 101 which belong to the 6:00 a.m. treatment. In this experiment in the case of irrigation at 2:00 p.m., the number of pods per plant was significantly decreased in full and deficit irrigation. The results showed that although the irrigation frequency was the same, irrigation at maximum evapo-transpiration caused the plant to be under stress and the yield was reduced. In other word, it can be said that time of irrigation had no meaningful effect on the appearance and shape of the plant while it was effective in terms of the yield. Overall assessments showed that maximum of the measured features were obtained in the case of 6:00 a.m. treatment

  2. Potato yield and yield structure depending on irrigation

    Directory of Open Access Journals (Sweden)

    Milić Stanko

    2010-01-01

    Full Text Available In the agroclimatic conditions of the Vojvodina Province, the application of an economic water regime and modern technology is necessary for stable and intensive potato production. A two-year experiment on calcareous chernozem was carried out to determine how irrigation and different pre-irrigation soil moisture affect potato yield and distribution of tuber fraction in the potato yield. The block-design trial had four replicates and was adapted for sprinkler irrigation conditions. It included four treatments: irrigation with pre-irrigation moisture levels of 60 % of field water capacity (FC, irrigation with pre-irrigation moisture levels of 70 % (FC, irrigation with pre-irrigation moisture levels of 80% (FC, and a non-irrigated control treatment. Irrigation significantly increased the yield of potato, which increased from 37.27 % to 75.86 %. Under irrigation, the percentage of small fractions decreased in favour of the 55 mm one, or fractions above the 45-55 mm range. On average, irrigated treatments produced significantly more tubers than the conditions of natural water supply. .

  3. Sediment Transport Model for a Surface Irrigation System

    Directory of Open Access Journals (Sweden)

    Damodhara R. Mailapalli

    2013-01-01

    Full Text Available Controlling irrigation-induced soil erosion is one of the important issues of irrigation management and surface water impairment. Irrigation models are useful in managing the irrigation and the associated ill effects on agricultural environment. In this paper, a physically based surface irrigation model was developed to predict sediment transport in irrigated furrows by integrating an irrigation hydraulic model with a quasi-steady state sediment transport model to predict sediment load in furrow irrigation. The irrigation hydraulic model simulates flow in a furrow irrigation system using the analytically solved zero-inertial overland flow equations and 1D-Green-Ampt, 2D-Fok, and Kostiakov-Lewis infiltration equations. Performance of the sediment transport model was evaluated for bare and cropped furrow fields. The results indicated that the sediment transport model can predict the initial sediment rate adequately, but the simulated sediment rate was less accurate for the later part of the irrigation event. Sensitivity analysis of the parameters of the sediment module showed that the soil erodibility coefficient was the most influential parameter for determining sediment load in furrow irrigation. The developed modeling tool can be used as a water management tool for mitigating sediment loss from the surface irrigated fields.

  4. Coil irrigation in sugar cane (Saccharum officinarum

    Directory of Open Access Journals (Sweden)

    Jesús Sánchez Gutiérrez

    2016-01-01

    Full Text Available This study was made at the Basic Seed Bank of the Local Sugar Cane Research Station for the Mideastern Cuba, based in Camaguey, on brown carbonate soil, between 2013 and 12014. Coil irrigation was applied to meet the water requirements for the crop, according to the edafoclimatic conditions and the different phenological phases it has. The Savo method was used to determine useful rain water. Adjustment and complementation of the irrigation program was based on indicators that characterize the exploitation scheme. The machine´s working parameters were determined to meet the water needs, and increase crop´s overall yields. The evaluations and results achieved have contributed to new proposals for management and operation of coil irrigation, and they are important to increase its efficiency.

  5. Dwarf cashew growth irrigated with saline waters

    Directory of Open Access Journals (Sweden)

    Hugo Orlando Carvallo Guerra

    2009-12-01

    Full Text Available The cashew production is one of the most important agricultural activities from the social-economical viewpoint for the North East of Brazil; besides to produce a great deal of hand labor, it is very important as an exporting commodity. The inadequate use of irrigation in the semi arid regions of the North East of Brazil has induced soil salinization and consequently problems for the irrigated agriculture. In spite of this, few works have been conducted to study the effect of saline stress on the growth and development of the cashew. Because of the lack of information for this crop, an experiment was conducted to study the effect of salinity stress on the phytomass production and nutrient accumulation on the different organs of the precocious dwarf cashew (Anacardium occidentale L. clone CCP76. The study was conducted under controlled conditions using as statistical scheme a randomized block design factorial with six replicates. Five salinity treatments were considered for the irrigation water (electrical conductivities of 0.8, 1.6, 2.4, 3.2 and 4.0 dS m-1 at 25oC. The increasing in salinity of the irrigation water reduced the phytomass at different organs of the studied plant. The nitrogen, phosphorus, potassium, chloride and sodium in the plant varied with the salinity of the irrigation water according with the part of the plant analyzed; in some parts increased, in others decreased, in others increased initially and decreased afterwards, and finally, in other part of the plant the salinity of the irrigation water did not affect the nutrient concentration.

  6. Contribution to the improvement of irrigation management practices through water - deficit irrigation

    International Nuclear Information System (INIS)

    Bazza, M.

    1995-01-01

    The study aimed at identifying irrigation management practices which could result in water savings through -water deficit irrigation. Two field experiments, one on wheat and the other on sugar beet, were conducted and consisted of refraining from supplying water during specific stages of the cycle so as to identy the period(s) during which water deficit would have a limited effect on crop production. In the case of wheat, high water deficit occurred during the early and during these stages was the most beneficial for the crop. However, one water application during the tillering stage allowed the yield to be lower only to that of the treatement with three irrigations. Irrigation during the stage of grain filling caused the kernel weight to be as high as under three irrigations. The lowest value corresponded to the treatement with one irrigation during grain filling and that under rainfed conditions. For sugar beet, when water stress was was applied early in the crop cycle, its effect could be almost entirely recovered with adequate watering during the rest of the growing season. On the opposite, good watering early in cycle, followed by a stress, resulted in the second lowest yield. Water deficit during the maturity stage had also a limited effect on yield. The most crucial periods for adequate watering were which correspond to late filiar development and root growth which coincided with the highest water requirements period. For the same amount of water savings through deficit irrigation, it was better to partition the stress throughout the cycle than during the critical stages of the crop. However, at the national level, it would have been more important to practice deficit irrigation and the irrigated area. For both crops, high yields as high as water - use efficiency values could have been obtained. 8 tabs; 5 refs ( Author )

  7. Evaluation of mulched drip irrigation for cotton in arid Northwest China

    NARCIS (Netherlands)

    Wang, Z.; Jin, M.; Simunek, J.; van Genuchten, M.T.

    2014-01-01

    Field experiments were conducted in arid Southern Xinjiang, Northwest China, for 3 years to evaluate sustainable irrigation regimes for cotton. The experiments involved mulched drip irrigation during the growing season and flood irrigation afterward. The drip irrigation experiments included control

  8. Strategy of Irrigation Branch in Russia

    Science.gov (United States)

    Zeyliger, A.; Ermolaeva, O.

    2012-04-01

    At this moment, at the starting time of the program on restoration of a large irrigation in Russia till 2020, the scientific and technical community of irrigation branch does not have clear vision on how to promote a development of irrigated agriculture and without repeating of mistakes having a place in the past. In many respects absence of a vision is connected to serious backlog of a scientific and technical and informational and technological level of development of domestic irrigation branch from advanced one. Namely such level of development is necessary for the resolving of new problems in new conditions of managing, and also for adequate answers to new challenges from climate and degradation of ground & water resources, as well as a rigorous requirement from an environment. In such important situation for irrigation branch when it is necessary quickly generate a scientific and technical politics for the current decade for maintenance of translation of irrigated agriculture in the Russian Federation on a new highly effective level of development, in our opinion, it is required to carry out open discussion of needs and requirements as well as a research for a adequate solutions. From political point of view a framework organized in FP6 DESIRE 037046 project is an example of good practice that can serve as methodical approach how to organize and develop such processes. From technical point of view a technology of operational management of irrigation at large scale presents a prospective alternative to the current type of management based on planning. From point of view ICT operational management demands creation of a new platform for the professional environment of activity. This platform should allow to perceive processes in real time, at their partial predictability on signals of a straight line and a feedback, within the framework of variability of decision making scenarious, at high resolution and the big ex-awning of sensor controls and the gauges

  9. Moderate irrigation intervals facilitate establishment of two desert shrubs in the Taklimakan Desert Highway Shelterbelt in China.

    Science.gov (United States)

    Li, Congjuan; Shi, Xiang; Mohamad, Osama Abdalla; Gao, Jie; Xu, Xinwen; Xie, Yijun

    2017-01-01

    Water influences various physiological and ecological processes of plants in different ecosystems, especially in desert ecosystems. The purpose of this study is to investigate the response of physiological and morphological acclimation of two shrubs Haloxylon ammodendron and Calligonum mongolicunl to variations in irrigation intervals. The irrigation frequency was set as 1-, 2-, 4-, 8- and 12-week intervals respectively from March to October during 2012-2014 to investigate the response of physiological and morphological acclimation of two desert shrubs Haloxylon ammodendron and Calligonum mongolicunl to variations in the irrigation system. The irrigation interval significantly affected the individual-scale carbon acquisition and biomass allocation pattern of both species. Under good water conditions (1- and 2-week intervals), carbon assimilation was significantly higher than other treatments; while, under water shortage conditions (8- and 12-week intervals), there was much defoliation; and under moderate irrigation intervals (4 weeks), the assimilative organs grew gently with almost no defoliation occurring. Both studied species maintained similar ecophysiologically adaptive strategies, while C. mongolicunl was more sensitive to drought stress because of its shallow root system and preferential belowground allocation of resources. A moderate irrigation interval of 4 weeks was a suitable pattern for both plants since it not only saved water but also met the water demands of the plants.

  10. Vergence increases the gain of the human angular vestibulo-ocular reflex during peripheral hyposensitivity elicited by cold thermal irrigation.

    Science.gov (United States)

    Tamás, László T; Lundberg, Yunxia W; Büki, Béla

    2018-01-01

    When viewing a far target, the gain of the horizontal vestibulo-ocular reflex (VOR) is around 1.0, but when viewing a near target there is an increased response. It has been shown that while this convergence-mediated modulation is unaffected by canal plugging and clinically practical transmastoid galvanic stimulation, it is eliminated by a partial peripheral gentamicin lesion. The aim of this study was to determine if convergence increases the gain during peripheral hyposensitivity elicited by cold thermal irrigation. The high frequency VOR gain was measured using video head impulse testing immediately after the cold caloric stimulus in 9 healthy human subjects with the lateral semicircular canals oriented approximately earth-vertical. Before caloric irrigation, near viewing (15 cm) increased the average VOR gain by 28% (from 1 to 1.28). Cold (24°C) water irrigation of the right ear decreased the gain to 0.66 (far viewing) and 0.82 (near viewing) (22% difference). Although vergence also increased the gain for impulses to the left to the same degree before caloric stimulus, the caloric irrigation itself (applied to the right ear) did not influence the gain for contralateral impulses. In our experiments vergence increased the gain of the human angular VOR during peripheral hyposensitivity elicited by cold thermal irrigation. These results suggest that cold irrigation does not abolish the function of the nonlinear/phasic vestibular afferent pathway.

  11. Low Cost Constant – Head Drip Irrigation Emitter for Climate ...

    African Journals Online (AJOL)

    Low Cost Constant – Head Drip Irrigation Emitter for Climate Change Adaptation in Nigeria: Engineering Design and Calibration. ... The drip system comprises of abarrel, sub-main line, lateral lines, tubes and emitters, it can irrigate140 crop ...

  12. Influence of local topography on precision irrigation management

    Science.gov (United States)

    Precision irrigation management is currently accomplished using spatial information about soil properties through soil series maps or electrical conductivity (EC measurements. Crop yield, however, is consistently influenced by local topography, both in rain-fed and irrigated environments. Utilizing ...

  13. The Reticulation Irrigation Scheme at Sankana, Upper West Region ...

    African Journals Online (AJOL)

    farmers utilizing the irrigation project are food secure. ... The effects of ... Often, lack of maintenance, bad management and financial difficulties decrease the ...... and Mushunje A. (2010), 'Analysis of Irrigation Development Post Fast Track Land ...

  14. Modernisation strategy for National Irrigation Systems in the Philippines

    NARCIS (Netherlands)

    Delos Reyes, Mona Liza Fortunado

    2017-01-01

    The performance of publicly funded canal irrigation systems or more commonly called national irrigation systems (NIS) in the Philippines remained below expectations despite considerable system rehabilitation and improvement efforts. The continued suboptimal performances were attributed to

  15. Evaluation some Forage Legumes in Limited Irrigation Condition

    Directory of Open Access Journals (Sweden)

    Hassan Moniri Far

    2015-11-01

    Full Text Available Forage legumes respond differently to limited irrigation regimes. Their evaluation may, thus, help to select drought tolerant types for limited irrigation conditions. In this study four type of forage legume were studied for two years in Tikma-Dash Research Station of East Azarbaijan Agricultural and Natural Research Center, Tabriz, Iran, in a randomized complete block design using split-plot experiment in 2011-2013 years. Irrigation regimes (without irrigation, one irrigation and two irrigations were assigned to main plots and four forage types (hairy vetch, grass pea, Pannonica sativa and lathyrus were assigned to subplots. The results of analysis of variance showed that the effect of irrigation on plant height, number of shoots, leaf area and plant fresh and dry weights were not significant. Howere, legume types affected these traits significantly (P≤0.01. The effect of irrigation levels and legume types on protein content of hay were significant (P

  16. Automated irrigation systems for wheat and tomato crops in arid ...

    African Journals Online (AJOL)

    2017-04-02

    Apr 2, 2017 ... Many methods have been described and sensors developed to manage irrigation ... time, and automated irrigation systems based on crop water needs can .... output components, and a software program for decision support.

  17. Heavy metals accumulation in edible part of vegetables irrigated ...

    African Journals Online (AJOL)

    Hassana Ibrahim Mustapha

    water quality and permissible levels of metals in food and water. It revealed that the heavy .... irrigation with partially treated or untreated sewage. This was reported by .... Reuse of domestic grey water for irrigation of food crops, unpublished ...

  18. Wireless sensor networks for canopy temperature sensing and irrigation management

    Science.gov (United States)

    For researchers, canopy temperature measurements have proven useful in characterizing crop water stress and developing protocols for irrigation management. Today, there is heightened interest in using remote canopy temperature measurements for real-time irrigation scheduling. However, without the us...

  19. Is the Revitalisation of Smallholder Irrigation Schemes (RESIS ...

    African Journals Online (AJOL)

    2013-09-30

    Sep 30, 2013 ... including rainwater harvesting, flood recession, flood water spreading, river ... Smallholder irrigation systems can comprise farmers who use shared or ...... on Irrigation and Drainage, 15-17 November 2006, Aventura. Swadini.

  20. Economic Analysis of Crop Production under Jibiya Irrigation Project ...

    African Journals Online (AJOL)

    Majority of the farmers were married and can read and write. Most of ... The performance of the farmers, though ... holder irrigation dependent on the shadoof system of lifting water as .... implies that in Jibiya Irrigation Project, women were not.

  1. Performance of arthroscopic irrigation systems assessed with automatic blood detection

    NARCIS (Netherlands)

    Tuijthof, G. J. M.; de Vaal, M. M.; Sierevelt, I. N.; Blankevoort, L.; van der List, M. P. J.

    2011-01-01

    During arthroscopies, bleeding episodes occur as a result of tissue damage. Irrigation systems assist in minimizing these disturbances. The performance of three arthroscopic irrigation systems in clearing bleeding episodes was evaluated objectively. One surgeon performed 99 shoulder arthroscopies

  2. Impact of upstream industrial effluents on irrigation water quality ...

    African Journals Online (AJOL)

    Impact of upstream industrial effluents on irrigation water quality, soils and ... Knowledge of irrigation water quality is critical to predicting, managing and reducing salt ... Presence of heavy metals in concentration higher than the recommended ...

  3. Irrigation of steppe soils in the south of Russia: Problems and solutions (Analysis of Irrigation Practices in 1950-1990)

    Science.gov (United States)

    Minashina, N. G.

    2009-07-01

    Experience in irrigation of chernozems in the steppe zone of Russia for a period from 1950 to 1990 is analyzed. By the end of this period and in the subsequent years, the areas under irrigation reduced considerably, and the soil productivity worsened. This was caused by the improper design of irrigation systems, on the one hand, and by the low tolerance of chernozems toward increased moistening upon irrigation, on the other hand. The analysis of the factors and regimes of soil formation under irrigation conditions shows that irrigation-induced changes in the soil hydrology also lead to changes in the soil physicochemical, biochemical, and other properties. In particular, changes in the composition of exchangeable cations lead to the development of solonetzic process. In many areas, irrigation of chernozems was accompanied by the appearance of solonetzic, vertic, saline, and eroded soils. The development of soil degradation processes is described. In general, the deterioration of irrigated chernozems was related to the absence of adequate experience in irrigation of steppe soils, unskilled personnel, improper regime of irrigation, and excessively high rates of watering. In some cases, the poor quality of irrigation water resulted in the development of soil salinization and alkalization. To improve the situation, the training of personnel is necessary; the strategy of continuous irrigation should be replaced by the strategy of supplementary irrigation in the critical periods of crop development.

  4. Green and blue water footprint reduction in irrigated agriculture: effect of irrigation techniques, irrigation strategies and mulching

    NARCIS (Netherlands)

    Chukalla, Abebe Demissie; Krol, Martinus S.; Hoekstra, Arjen Ysbert

    2015-01-01

    Consumptive water footprint (WF) reduction in irrigated crop production is essential given the increasing competition for freshwater. This study explores the effect of three management practices on the soil water balance and plant growth, specifically on evapotranspiration (ET) and yield (Y) and

  5. Faraday space in a high-frequency γ discharge and the influence of pressure on the normal current density effect of an α discharge and the nature of the α-γ transition

    International Nuclear Information System (INIS)

    Raizer, Yu.P.; Shneider, M.N.

    1992-01-01

    The essential differences between high-frequency capacative discharges at intermediate and low pressures are considered. A theory is developed for the negative emission region and the Faraday dark space in a γ discharge. It is based on the kinetic equation for electrons in the highly nonuniform field of an electrode sheath, which is solved in the forward-backward approximation. If a uniform positive column is formed in the middle of the gap of a γ discharge of average pressure which is not too short, then at low pressures the hf plasma acts as the equivalent of the negative emission or Faraday space of a glow discharge with a typical weak field and low electron temperature. A region of reversed average field also appears, which is characteristic of a glow discharge. The question of the normal current density effect in an α discharge is discussed. This effect is observed at average pressures. At low pressures the effect disappears, and even weak current covers the entire electrode; the pressures at which this occurs and the reasons for it are demonstrated. The nature of the α-γ transition, which takes place discontinuously at average pressures but continuously at lower pressures, is discussed. The reason for this behavior is discussed and the pressure at which the discontinuous mechanism changes into continuous is estimated

  6. Drip Irrigation for Commercial Vegetable and Fruit Production

    OpenAIRE

    Maughn, Tiffany; Allen, Niel; Drost, Dan

    2017-01-01

    Drip irrigation is a highly efficient irrigation method well suited to many fruit and vegetable row crops. Drip tubing or tape discharges water to the soil through emitters positioned close to the plant. The drip tubing can be placed uncovered on the soil surface, under plastic mulch, buried in the soil, or suspended above the ground (e.g., on a trellis system). Water application rate is relatively low and irrigations are usually frequent. Properly designed and maintained drip-irrigation syst...

  7. Ring Irrigation System (RIS) design through customer preference representation

    OpenAIRE

    Ridwan Infandra I.Z.; Rianmora Suchada; Werawatganon Siwat

    2018-01-01

    In agricultural field, irrigation is one of the most interesting considerations affecting the rate of plant growth and development. Micro-irrigation as the dripping or sprinkle method is one of the irrigation types that applies the small amount of water for fulfilling the humidity requirement. The most important factors affecting the demand of water for plants are soil conditions and effect of climatic factors. With less human labour required, to improve the irrigation method from the recent ...

  8. The management perspective on the performance of the irrigation subsector

    OpenAIRE

    Nijman, C.

    1993-01-01

    INVESTMENT IN IRRIGATION has been immense in the past. Estimated average annual investments of US$ 15 billion makes irrigation the largest subsector of the agricultural sector, that is itself by far the largest sector of development investment. Since the mid-1960s the awareness spread that the performance of irrigation investments was far below its potential. The size of this underperformance is well represented by Seckler's alarming conclusion that the average irrigation investment costs twi...

  9. Mapping Irrigation Potential in the Upper East Region of Ghana

    Science.gov (United States)

    Akomeah, E.; Odai, S. N.; Annor, F. O.; Adjei, K. A.; Barry, B.

    2009-04-01

    The Upper East Region together with the other two regions in Northern Ghana (Upper West and Northern Region) is seen as the locus of perennial food deficit (GPRS, 2003). Despite, the provision of over 200 small scale dams and various mechanisms aimed at poverty alleviation, the region is still plagued with poverty and yearly food shortages. To achieve food security and alleviate poverty in the region however, modernization of agriculture through irrigation is deemed inevitable. While it is true that considerable potential still exists for future expansion of irrigation, it cannot be refuted that water is becoming scarcer in the regions where the need for irrigation is most important, hence mapping the irrigation potential of the region will be the first step toward ensuring sound planning and sustainability of the irrigation developments. In this study, an attempt has been made to map out the irrigation potential of the Upper East Region. The river basin approach was used in assessing the irrigation potential. The catchments drained by The White Volta river, Red volta river, River Sissili and River Kulpawn were considered in the assessment. The irrigation potential for the sub basins was computed by combining information on gross irrigation water requirements for the selected cash crops, area of soil suitable for irrigation and available water resources. The capacity of 80%, 70%, 60% and 50% time of exceedance flow of the available surface water resources in the respective sub basins was estimated. The area that can be irrigated with this flow was computed with selected cropping pattern. Combining the results of the potential irrigable areas and the land use map of the respective sub basins, an irrigation potential map has been generated showing potential sites in the upper east region that can be brought under irrigation. Keywords: Irrigation potential, irrigation water requirement, land evaluation, dependable flow

  10. Effect of Irrigation with Wastewater on Certain Soil Physical and Chemical properties

    Directory of Open Access Journals (Sweden)

    Farzad Rohani Shahraki

    2005-03-01

    Full Text Available Depending on effluent characteristics, irrigation with wastewater plant effluent can be either beneficial or harmful. To investigate the effects of nine years of irrigation with North Isfahan Wastewater Treatment Plant effluent on physical and chemical properties of soil, a study was carried out using a randomized complete block design with three replications. Treatments included: 1 raw wastewater; 2 effluent from primary settling basin; 3 final plant effluent and 4 well water. To investigate soil physical and chemical properties, samples were taken from depths of 0-5 cm and 5-10 cm from each plot. The results showed that raw wastewater COD and SS were higher than the Iranian Standard limits for use in irrigation. So were BOD5 and turbidity of effluent from primary sedimentation tanks. From the results obtained, the raw wastewater may be considered to be of medium quality. However, regarding other parameters such as EC, SAR, Na and Pb, the quality of the raw wastewater was considerably higher than that of well water. All treatments showed medium infiltrability with respect to chloride concentration. The concentration of lead in well water was higher than in treated wastewater. It should be noted that lead concentration in all samples was less than the standard limits. The average soil bulk density and percentage of moisture in FC did not follow any specific trend. The results indicate that the soil irrigated with effluent over the nine years had a lower bulk density, a higher percentage of moisture, and a lower infiltration compared to adjacent soil not irrigated with wastewater. Analysis of variance for all results did not confirm any significant differences among treatments.

  11. Effects of seedbed preparation, irrigation, and water harvesting of seedling emergence at the Nevada Test Site

    International Nuclear Information System (INIS)

    Winkel, V.K.; Ostler, W.K.; Gabbert, W.D.; Lyon, G.E.

    1994-02-01

    Approximately 800 hectares on the US Department of Energy Nevada Test Site and vicinity are contaminated with plutonium. As part of a cleanup effort, both the indigenous vegetation and the top 5--10 cm of soil may be removed, and the soil may or may not be replaced. Technologies must be developed to stabilize and revegetate these lands. A study was developed to determine adaptable plant species, methods to prepare seedbeds for direct seeding and water harvesting, and proper irrigation rates. Plots were cleared of indigenous vegetation, and then prepared with various seedbed/water harvesting treatments including, pitting, land imprinting, and mulching. Other plots were treated with large water harvesting structures. Three irrigation treatments were superimposed over the seedbed/water harvesting treatments. Seedling emergence data was collected, and the treatment combinations compared. Supporting meteorological and soil data were collected with an automatic data-logger. Specific data included precipitation, and air temperature. In a year of above-average precipitation, irrigation did not generally aid germination and emergence of seeded species, and only slightly increased densities of species from the native seedbank. With the exception of increased shrub seedling densities in desert strips, there were no strong seedbed preparation/water harvesting treatment effects. In years of above-average rainfall, mulching and water harvesting treatments, irrigation may not be necessary to insure adequate germination and emergence of adapted perennial grasses, forbs, and shrubs in the Mojave/Great Basin Transition Desert. Future collection of survival data will determine whether a maintenance irrigation program is necessary to ensure establishmnent of native plants

  12. Soil and water management in spate irrigation systems in Eritrea

    NARCIS (Netherlands)

    Hadera, M.T.

    2001-01-01

    Spate irrigation has been practised over 100 years in the Red Sea coastal zone of Eritrea such as the Sheeb area. Main problem of the spate irrigation system is water shortage caused by irregular rainfall in the highlands of Eritrea and breaching of the irrigation structures by destructive

  13. Potentials for Supplemental Irrigation in Some Rainfall Areas of Imo ...

    African Journals Online (AJOL)

    In addition, there were up to five months of the year during which rainwater was much in deficit of evapotranspiration. All these stress the need for irrigation. Analysis of water quality (surface, groundwater, and rainfall runoff) showed their suitability for irrigation. Quantity assessment of supplemental irrigation during the dry ...

  14. Greenhouse evaluation of deficit irrigation on the growth of tomato ...

    African Journals Online (AJOL)

    Deficit irrigation is considered to be an important approach for crop cultivation in dry regions where water resources are scarce. Deficit irrigation can be used also to decrease the level of infections by some moisturedependent plant pests and diseases such as root-knot nematode disease. Therefore, deficit irrigation at levels ...

  15. Field evaluation of deficit irrigation effects on tomato growth ...

    African Journals Online (AJOL)

    Two field experiments were conducted using a common tomato cultivar (GS12) to assess the effect of deficit irrigation (DI) regimes on tomato growth performance, and on root-knot nematode Meloidogyne javanica galling and abundance. Irrigation treatments consisted of five irrigation regimes: 20%, 40%, 60%, 80% and ...

  16. The impact of smallholder irrigation on household welfare: The case ...

    African Journals Online (AJOL)

    The potential of smallholder irrigated agriculture to enhance food security and alleviate rural poverty has led the South African Government to prioritise and invest significantly in irrigation establishment, rehabilitation and revitalisation. The question addressed in this study pertains to the extent to which smallholder irrigation ...

  17. Effects of seven different irrigation techniques on debris and the ...

    African Journals Online (AJOL)

    Aim: Conventional manual irrigation with a syringe and needle remains widely accepted technique in the irrigation procedures. However, its flushing action has some limitations. Currently, several techniques and systems are available and reported to improve the insufficiency of syringe irrigation. The aim of this study was to ...

  18. Critical parameters for maize yield under irrigation farming in the ...

    African Journals Online (AJOL)

    This study examines the critical variables that determine maize yield under irrigation farming in the savanna ecological zone of Kwara State. Seventy-five soil samples were randomly collected from irrigation farm of Oke-Oyi irrigation project of the Lower Niger River Basin Development Authority Ilorin and bulked into 15 ...

  19. Surge flow irrigation under short field conditions in Egypt

    NARCIS (Netherlands)

    Ismail, S.M.; Depeweg, H.; Schultz, E.

    2004-01-01

    Several studies carried out in long furrows have shown that surge flow irrigation offers the potential of increasing the efficiency of irrigation. The effects of surge flow in short fields, such as in Egypt, are still not well known, however. To investigate the effect of surge flow irrigation in

  20. Evaluation of potential water conservation using site-specific irrigation

    Science.gov (United States)

    With the advent of site-specific variable-rate irrigation (VRI) systems, irrigation can be spatially managed within sub-field-sized zones. Spatial irrigation management can optimize spatial water use efficiency and may conserve water. Spatial VRI systems are currently being managed by consultants ...

  1. Scheduling irrigation for jujube ( Ziziphus jujuba Mill. ) | Zhang ...

    African Journals Online (AJOL)

    This study was performed to select suitable indicator for scheduling the irrigation of jujube (Ziziphus jujuba Mill.) grown in the Loess Plateau. The relationships between plant-based indicators and soil matrix potential as well as meteorological factors of jujube under deficit irrigation compared with well irrigation were ...

  2. Limited irrigation research and infrared thermometry for detecting water stress

    Science.gov (United States)

    The USDA-ARS Limited Irrigation Research Farm, located outside of Greeley Colorado, is an experiment evaluating management perspectives of limited irrigation water. An overview of the farm systems is shown, including drip irrigation systems, water budgeting, and experimental design, as well as preli...

  3. Irrigation development and management in Ghana: Prospects and ...

    African Journals Online (AJOL)

    ... existing schemes. It is envisaged that irrigation will be seen in its right perspective as a multidisciplinary activity to ensure the success of schemes. There is the need for running a postgraduate programme in irrigation at the KNUST to enhance the nations efforts at developing and managing irrigation projects successfully.

  4. Technical descriptions of ten irrigation technologies for conserving energy

    Energy Technology Data Exchange (ETDEWEB)

    Harrer, B.J.; Wilfert, G.L.

    1983-05-01

    Technical description of ten technologies which were researched to save energy in irrigated agriculture are presented. These technologies are: well design and development ground water supply system optimization, column and pump redesign, variable-speed pumping, pipe network optimization, reduced-pressure center-pivot systems, low-energy precision application, automated gated-pipe system, computerized irrigation scheduling, and instrumented irrigation scheduling. (MHR)

  5. Modelling the economic trade-offs of irrigation pipeline investments ...

    African Journals Online (AJOL)

    The Soil Water Irrigation Planning and Energy Management (SWIP-E) mathematical programming model was developed and applied in this paper to provide decision support regarding the optimal mainline pipe diameter, irrigation system delivery capacity and size of the irrigation system. SWIP-E unifies the interrelated ...

  6. Tracking antibiotic resistance genes in soil irrigated with dairy wastewater

    Science.gov (United States)

    In southern Idaho, the application of dairy wastewater to agricultural soils is a widely used practice to irrigate crops and recycle nutrients. In this study, small-scale field plots were irrigated monthly (6 times) with dairy wastewater (100%), wastewater diluted to 50% with irrigation (canal) wate...

  7. Sustainable Irrigation Development in the White Volta Sub-Basin

    NARCIS (Netherlands)

    Ofosu, E.A.

    2011-01-01

    This study on sustainable irrigation development identified growing markets for irrigated products as an important driving force behind the expansion of irrigation which has given rise to new technologies. The new technologies have spread because they gave farmers direct control over water sources.

  8. Saline water irrigation of quinoa and chickpea

    DEFF Research Database (Denmark)

    Hirich, A.; Jelloul, A.; Choukr-Allah, R.

    2014-01-01

    A pot experiment was conducted in the south of Morocco to evaluate the response of chickpea and quinoa to different irrigation water salinity treatments (1, 4, 7 and 10 dS m-1 for chickpea and 1, 10, 20 and 30 dS m-1 for quinoa). Increasing salinity affected significantly (P

  9. Irrigation scheduling using soil moisture sensors

    Science.gov (United States)

    Soil moisture sensors were evaluated and used for irrigation scheduling in humid region. Soil moisture sensors were installed in soil at depths of 15cm, 30cm, and 61cm belowground. Soil volumetric water content was automatically measured by the sensors in a time interval of an hour during the crop g...

  10. Measurement Of Technical Efficiency In Irrigated Vegetable ...

    African Journals Online (AJOL)

    This study measured technical efficiency and identified its determinants in irrigated vegetable production in Nasarawa State of Nigeria using a stochastic frontier model. A complete enumeration of 193 NADP-registered vegetable farmers was done. The predicted farm technical efficiency ranges from 25.94 to 96.24 per cent ...

  11. CORRELATION AMONG FLUORIDE AND METALS IN IRRIGATION ...

    African Journals Online (AJOL)

    Preferred Customer

    The levels of fluoride and selected metals in Ethiopian Rift Valley soils and irrigation water in the nearby sources were ... exhaust fumes, process waters and waste from various industrial processes [1]. The uses of ... into four sub-systems: Lake Rudolf, Chew Bahir, the Main Ethiopian Rift (MER) and the Afar. The seismically ...

  12. Water quality and irrigation [Chapter 10

    Science.gov (United States)

    Thomas D. Landis; Kim M. Wilkinson

    2009-01-01

    Water is the single most important biological factor affecting plant growth and health. Water is essential for almost every plant process: photosynthesis, nutrient transport, and cell expansion and development. In fact, 80 to 90 percent of a seedling's weight is made up of water. Therefore, irrigation management is the most critical aspect of nursery operations....

  13. Irrigation performance assessment in Crimea, Ukraine

    NARCIS (Netherlands)

    Pavlov, S.S.; Roerink, G.J.; Hellegers, P.J.G.J.; Popovych, V.F.

    2006-01-01

    After the collapse of the Soviet Union the performance of irrigated agriculture decreased drastically in Ukraine, due to problems related to the transition from a centrally planned economy to a market economy. Before formulating recommendations on required actions to modify this problematic

  14. Irrigation management of muskmelon with tensiometry

    Directory of Open Access Journals (Sweden)

    Márcio José de Santana

    2017-11-01

    Full Text Available The production and consumption of muskmelon have been increasing (MELO et al., 2014, thus, information on techniques for higher field productions are necessary. The experiment described in the present work was conducted in the IFTM, Uberaba, State of Minas Gerais, Brazil, aiming to evaluate the muskmelon yield under different soil water tensions. A randomized block experimental design was used with five treatments (soil water tensions of 10, 20, 30, 40 and 50 kPa and four replications (plots of two rows of 14 plants. Two harvests were carried out and the fruit yield, stem diameter, number of fruits per plant and efficiency of water use were evaluated. Irrigation was performed with a drip irrigation system and managed with tensiometry. The cultivar Bonus n.2 was used with spacing of 1.0 x 0.6 m. The data of the variables were subjected to the F test and regression test. The treatments showed statistical differences in number of fruits per plant, fruit weight (fruit yield and stem diameter. The highest fruit yield found was 1.36 kg fruit-1 and the highest water use efficiency was 4.08 g mm-1 with irrigation for a soil water tension of 10 kPa. The lowest fruit yield was found with irrigation for a soil water tension of 50 kPa.

  15. New soil water sensors for irrigation management

    Science.gov (United States)

    Effective irrigation management is key to obtaining the most crop production per unit of water applied and increasing production in the face of competing demands on water resources. Management methods have included calculating crop water needs based on weather station measurements, calculating soil ...

  16. FAO study on irrigation potential for Africa

    OpenAIRE

    Food and Agriculture Organization of the United Nations.‏ United Nations Development Programme

    2002-01-01

    Metadata only record To improve the conjunctive use of sub-surface and surface water in order to increase water resources availability for sustainable small-scale irrigation development in support of food security in West Africa, south of the Sahara.

  17. Zone edge effects with variable rate irrigation

    Science.gov (United States)

    Variable rate irrigation (VRI) systems may offer solutions to enhance water use efficiency by addressing variability within a field. However, the design of VRI systems should be considered to maximize application uniformity within sprinkler zones, while minimizing edge effects between such zones alo...

  18. Strategies of smallholder irrigation management in Zimbabwe

    NARCIS (Netherlands)

    Manzungu, E.

    1999-01-01

    The smallholder irrigation sub-sector in Zimbabwe, according to literature sources, is under threat due to what are called management problems. Poor water management and low crop yields have been cited, as has also been poor financial and economic viability, resulting in heavy government

  19. Streamflow Prediction in Ungauged, Irrigated Basins

    Science.gov (United States)

    Zhang, M.; Thompson, S. E.

    2016-12-01

    The international "predictions in ungauged basins" or "PUB" effort has broadened and improved the tools available to support water resources management in sparsely observed regions. These tools have, however, been primarily focused on regions with limited diversion of surface or shallow groundwater resources. Incorporating anthropogenic activity into PUB methods is essential given the high level of development of many basins. We extended an existing stochastic framework used to predict the flow duration curve to explore the effects of irrigation on streamflow dynamics. Four canonical scenarios were considered in which irrigation water was (i) primarily sourced from water imports, (ii) primarily sourced from direct in-channel diversions, (iii) sourced from shallow groundwater with direct connectivity to stream channels, or (iv) sourced from deep groundwater that is indirectly connected to surface flow via a shallow aquifer. By comparing the predicted flow duration curves to those predicted by accounting for climate and geomorphic factors in isolation, specific "fingerprints" of human water withdrawals could be identified for the different irrigation scenarios, and shown to be sensitive to irrigation volumes and scheduling. The results provide a first insight into PUB methodologies that could be employed in heavily managed basins.

  20. New Approaches to Irrigation Scheduling of Vegetables

    Directory of Open Access Journals (Sweden)

    Michael D. Cahn

    2017-04-01

    Full Text Available Using evapotranspiration (ET data for scheduling irrigations on vegetable farms is challenging due to imprecise crop coefficients, time consuming computations, and the need to simultaneously manage many fields. Meanwhile, the adoption of soil moisture monitoring in vegetables has historically been limited by sensor accuracy and cost, as well as labor required for installation, removal, and collection of readings. With recent improvements in sensor technology, public weather-station networks, satellite and aerial imaging, wireless communications, and cloud computing, many of the difficulties in using ET data and soil moisture sensors for irrigation scheduling of vegetables can now be addressed. Web and smartphone applications have been developed that automate many of the calculations involved in ET-based irrigation scheduling. Soil moisture sensor data can be collected through wireless networks and accessed using web browser or smartphone apps. Energy balance methods of crop ET estimation, such as eddy covariance and Bowen ratio, provide research options for further developing and evaluating crop coefficient guidelines of vegetables, while recent advancements in surface renewal instrumentation have led to a relatively low-cost tool for monitoring crop water requirement in commercial farms. Remote sensing of crops using satellite, manned aircraft, and UAV platforms may also provide useful tools for vegetable growers to evaluate crop development, plant stress, water consumption, and irrigation system performance.

  1. Reuse of drainage water from irrigated areas

    NARCIS (Netherlands)

    Willardson, L.S.; Boels, D.; Smedema, L.K.

    1997-01-01

    Increasing competition for water of good quality and the expectation that at least half of the required increase in food production in the near-future decades must come from the world's irrigated land requires to produce more food by converting more of the diverted water into food. Reuse of the

  2. The efficiency of drip irrigation unpacked

    NARCIS (Netherlands)

    Kooij, van der S.; Zwarteveen, M.Z.; Boesveld, H.; Kuper, M.

    2013-01-01

    Drip irrigation figures prominently in water policy debates as a possible solution to water scarcity problems, based on the assertion that it will improve water use efficiencies. We use this article to carefully trace the scientific basis of this assertion. Through a systematic review of the

  3. Solar-thermal jet pumping for irrigation

    Science.gov (United States)

    Clements, L. D.; Dellenback, P. A.; Bell, C. A.

    1980-01-01

    This paper describes a novel concept in solar powered irrigation pumping, gives measured performance data for the pump unit, and projected system performance. The solar-thermal jet pumping concept is centered around a conventional jet eductor pump which is commercially available at low cost. The jet eductor pump is powered by moderate temperature, moderate pressure Refrigerant-113 vapor supplied by a concentrating solar collector field. The R-113 vapor is direct condensed by the produced water and the two fluids are separated at the surface. The water goes on to use and the R-113 is repressurized and returned to the solar field. The key issue in the solar-thermal jet eductor concept is the efficiency of pump operation. Performance data from a small scale experimental unit which utilizes an electrically heated boiler in place of the solar field is presented. The solar-thermal jet eductor concept is compared with other solar irrigation concepts and optimal application situations are identified. Though having lower efficiencies than existing Rankine cycle solar-thermal irrigation systems, the mechanical and operational simplicity of this concept make it competitive with other solar powered irrigation schemes.

  4. Scheduling irrigation for jujube (Ziziphus jujuba Mill.)

    African Journals Online (AJOL)

    USER

    2010-08-30

    Aug 30, 2010 ... indicators for diagnosing plant water information, but it is troublesome to measure leaf water potential using a pressure chamber (Turner, 1981). It is also difficult to achieve automatic and continuous records with the pressure chamber. Definition of threshold values of soil moisture for irrigation management ...

  5. Prospects and Constraints of Household Irrigation Practices ...

    African Journals Online (AJOL)

    Water and soil samples were analyzed for major cations and anions, ... So, attention and investment in these areas have been very limited in Africa and ... The shape of the watershed is almost elliptical (Fig. 1). 2.1. Soil. Texturally ..... quality of the irrigation water, soil factors such as structure, degree of compaction, organic.

  6. Intervention processes and irrigation institutions : sustainability of farmer managed irrigation systems in Nepal

    OpenAIRE

    Pant, D.R.

    2000-01-01

    With the support from various donors, His Majesty's Government of Nepal has implemented support programmes with a view to transform water availability, improve production, and increase the institutional capabilities of farmers to develop and sustain efficient, fair and reliable irrigation management practices in irrigation systems in Nepal. In this respect, this study aimed to understand the social, administrative and political processes involved in the social and institutional chang...

  7. Irrigation et paludisme : un couple infernal?

    Directory of Open Access Journals (Sweden)

    Mergeai, G.

    2016-01-01

    Full Text Available Irrigation and Malaria - a Terrible Combination?. Increasing agricultural productivity is a priority in most of the developing countries and using irrigation is one of the most efficient ways of achieving this goal. Almost half a billion people in the world contract malaria every year and approximately one million die as a result. The majority of these victims are farmers or members of their families. In infected areas, malaria continues to have major negative impacts on agricultural productivity. For example, in the Equateur province of the DRC, after access to production means, fevers are considered the second biggest obstacle to the development of agricultural activities. In the Ivory Coast, a study has shown that growers suffering from malaria were about half as productive as their healthy colleagues. The disease often strikes at the start of the rainy season when work begins again in the fields. It reduces the amount of land cultivated and affects the amount of care taken with crops. Agricultural practices influence the risk of contracting malaria. Irrigation, in particular, can encourage the proliferation of vectors of the disease and make it more likely to spread. This tendency can be observed in many locations where irrigated rice production is on the increase. Paradoxically, however, an increased number of mosquitoes does not systematically result in more malaria. In Ethiopia, malaria is more prevalent close to the micro-dams sponsored by the government, whereas, in Tanzania, there is less malaria in irrigated areas. Various theories can be put forward in order to explain this paradox. In particular, increased income due to higher rice yields enables farmers to purchase insecticide-treated mosquito nets. It also allows them to eat better, which strengthens their immune systems. It also appears that the negative impact of irrigation systems is greater in areas, in which immunity levels were low in the population prior to the creation of

  8. Road density

    Data.gov (United States)

    U.S. Environmental Protection Agency — Road density is generally highly correlated with amount of developed land cover. High road densities usually indicate high levels of ecological disturbance. More...

  9. Evaluation of hydraulic performance of downstream-controlled Maira-PHLC irrigation canals under crop-based irrigation operations

    NARCIS (Netherlands)

    Munir, S.; Schultz, B.; Suryadi, F.X.; Bharati, L.

    2012-01-01

    Demand-based irrigation systems are operated according to crop water requirements. As crop water requirements remain variable throughout the growing season, the discharges in the canal also vary to meet demands. The irrigation system under study is a demand-based semi-automatic irrigation system,

  10. Comparison of traditional and ET-based irrigation scheduling of surface-irrigated cotton in the arid southwestern USA

    Science.gov (United States)

    The use of irrigation scheduling tools to produce cotton under-surface irrigation in the arid southwesternUSA is minimal. In the State of Arizona, where traditional irrigation scheduling is the norm, producersuse an average of 1460 mm annually to grow a cotton crop. The purpose of this paper was to ...

  11. Year-Round Irrigation Schedule for a Tomato–Maize Rotation System in Reservoir-Based Irrigation Schemes in Ghana

    Directory of Open Access Journals (Sweden)

    Ephraim Sekyi-Annan

    2018-05-01

    Full Text Available Improving irrigation management in semi-arid regions of Sub-Saharan Africa is crucial to respond to increasing variability in rainfall and overcome deficits in current irrigation schemes. In small-scale and medium-scale reservoir-based irrigation schemes in the Upper East region of Ghana, we explored options for improving the traditional, dry season irrigation practices and assessed the potential for supplemental irrigation in the rainy season. The AquaCrop model was used to (i assess current water management in the typical tomato-maize rotational system; (ii develop an improved irrigation schedule for dry season cultivation of tomato; and (iii determine the requirement for supplemental irrigation of maize in the rainy season under different climate scenarios. The improved irrigation schedule for dry season tomato cultivation would result in a water saving of 130–1325 mm compared to traditional irrigation practices, accompanied by approximately a 4–14% increase in tomato yield. The supplemental irrigation of maize would require 107–126 mm of water in periods of low rainfall and frequent dry spells, and 88–105 mm in periods of high rainfall and rare dry spells. Therefore, year-round irrigated crop production may be feasible, using water saved during dry season tomato cultivation for supplemental irrigation of maize in the rainy season.

  12. Evaluation of different methods of measuring evapotranspiration as a scheduling guide for drip-irrigated cotton

    International Nuclear Information System (INIS)

    Rawitz, E.; Marani, A.; Mahrer, Y.; Berkovich, D.

    1983-01-01

    Evapotranspiration in a drip-irrigated cotton field was estimated by the energy balance method, net radiation, standard evaporation pan, evaporation pan in the field at canopy height, and by the Penman equation, and the results were compared with the soil-water balance based on neutron meter and tensiometer data from seven observation sites. Evapotranspiration according to the soil-water balance was only about 85% of that determined by the energy balance method, and this is attributed to the fact that irrigation laterals were placed every second row, and the soil-water balance was determined in the irrigated rows. The crop also utilized moisture stored from winter rains in the unirrigated inter-row spaces, which was detected by the energy balance method. Actual evapotranspiration (ET) was 96% of potential ET (Penman), and the latter equalled 98% of net radiation energy. The actual ET equalled 90% of free water evaporation from the pan in the field at canopy height, and 88% of net radiation. The high-frequency drip regime maintained ET very close to potential ET, and under these conditions the field-installed evaporation pan, or the net radiometer, are good indicators of crop water use, with the latter being adaptable to computer-controlled irrigation. (author)

  13. Bayesian Belief Networks Approach for Modeling Irrigation Behavior

    Science.gov (United States)

    Andriyas, S.; McKee, M.

    2012-12-01

    Canal operators need information to manage water deliveries to irrigators. Short-term irrigation demand forecasts can potentially valuable information for a canal operator who must manage an on-demand system. Such forecasts could be generated by using information about the decision-making processes of irrigators. Bayesian models of irrigation behavior can provide insight into the likely criteria which farmers use to make irrigation decisions. This paper develops a Bayesian belief network (BBN) to learn irrigation decision-making behavior of farmers and utilizes the resulting model to make forecasts of future irrigation decisions based on factor interaction and posterior probabilities. Models for studying irrigation behavior have been rarely explored in the past. The model discussed here was built from a combination of data about biotic, climatic, and edaphic conditions under which observed irrigation decisions were made. The paper includes a case study using data collected from the Canal B region of the Sevier River, near Delta, Utah. Alfalfa, barley and corn are the main crops of the location. The model has been tested with a portion of the data to affirm the model predictive capabilities. Irrigation rules were deduced in the process of learning and verified in the testing phase. It was found that most of the farmers used consistent rules throughout all years and across different types of crops. Soil moisture stress, which indicates the level of water available to the plant in the soil profile, was found to be one of the most significant likely driving forces for irrigation. Irrigations appeared to be triggered by a farmer's perception of soil stress, or by a perception of combined factors such as information about a neighbor irrigating or an apparent preference to irrigate on a weekend. Soil stress resulted in irrigation probabilities of 94.4% for alfalfa. With additional factors like weekend and irrigating when a neighbor irrigates, alfalfa irrigation

  14. Automation in irrigation process in family farm with Arduino platform

    Directory of Open Access Journals (Sweden)

    Kianne Crystie Bezerra da Cunha

    2016-03-01

    Full Text Available The small farmers tend not to use mechanical inputs in the irrigation process due to the high cost than conventional irrigation systems have and in other cases, the lack of knowledge and technical guidance makes the farmer theme using the system. Thus, all control and monitoring are made by hand without the aid of machines and this practice can lead to numerous problems from poor irrigation, and water waste, energy, and deficits in production. It is difficult to deduce when to irrigate, or how much water applied in cultivation, measure the soil temperature variables, temperature, and humidity, etc. The objective of this work is to implement an automated irrigation system aimed at family farming that is low cost and accessible to the farmer. The system will be able to monitor all parameters from irrigation. For this to occur, the key characteristics of family farming, Arduino platform, and irrigation were analyzed.

  15. Biochar enhances yield and quality of tomato under reduced irrigation

    DEFF Research Database (Denmark)

    Saleem Akhtar, Saqib; Li, Guitong; Andersen, Mathias Neumann

    2014-01-01

    tBiochar is an amendment that can be used for enhancing soil water storage which may increase cropproductivity. The objective of this study was to investigate the effects of biochar on physiology, yield andquality of tomato under different irrigation regimes. From early flowering to fruit maturity...... stages, theplants were subjected to full irrigation (FI), deficit irrigation (DI) and partial root-zone drying irrigation(PRD) and two levels of biochar (0% and 5% by weight). In FI, the plants were irrigated daily to pot waterholding capacity while in DI and PRD, 70% of FI was irrigated on either...... the whole or one side of the pots,respectively. In PRD, irrigation was switched between sides when the soil water content of the dry sidedecreased to 15%. The results showed that addition of biochar increased the soil moisture contents in DIand PRD, which consequently improved physiology, yield, and quality...

  16. Precision overhead irrigation is suitable for several Central Valley crops

    Directory of Open Access Journals (Sweden)

    Jeffrey P. Mitchell

    2016-04-01

    Full Text Available Overhead systems are the dominant irrigation technology in many parts of the world, but they are not widely used in California even though they have higher water application efficiency than furrow irrigation systems and lower labor requirements than drip systems. With water and labor perennial concerns in California, the suitability of overhead systems merits consideration. From 2008 through 2013, in studies near Five Points, California, we evaluated overhead irrigation for wheat, corn, cotton, tomato, onion and broccoli as an alternative to furrow and drip irrigation. With the exception of tomato, equal or increased yields were achieved with overhead irrigation. Many variables are involved in the choice of an irrigation system, but our results suggest that, with more research to support best management practices, overhead irrigation may be useful to a wider set of California farmers than currently use it.

  17. The effects of extreme low frequency pulsed electromagnetic field on bone mineral density and incidence of fractures in patients with end - stage renal disease on dialysis - three year follow up study

    Directory of Open Access Journals (Sweden)

    Rakočević-Hrnjak Aleksandra

    2018-01-01

    Full Text Available Background/Aim. A variety of physical therapy options has been developed for the treatment of musculoskeletal disorders including those characterized with low bone mineral density (BMD. Extreme low frequency pulsed electromagnetic field (ELF-PEMF can accelerate bone formation. Patients with end stage of renal disease (ESRD are predisposed to high incidence of fractures due to bone disorder with multifactorial pathogenesis. Vitamin D, calcium supplements, antiresorptive and anabolic drugs in those patients have changed pharmacodynamics and pharmacokinetics and have minimal or limited effects. The aim of this study was to assess the effectiveness of long-term ELF-PEMF therapy applied in concordance with physical exercise on bone mass, incidence of new bone fractures and parathyroid hormone concentrations in ESRD patients on dialysis. Methods. In this 3-year prospective clinical trial, 151 patients with ESRD on dialysis program were subjected to treatment with ELF-PEMF (18 Hz, 2 mT applied during 40 min after 10 consecutive dialysis procedures, 4 times through one year (120 treatments in total during three years together with kinesitherapy (study group or only with kinesitherapy (control group on the voluntary basis. Results. Total of 124 patients have completed the study. In the study group (n = 54, regardless of sex, significant improvements of BMD, T-score and Z-score on both lumbar spine and femoral neck were achieved after 3-year treatment with ELF-PEMF. In the control group (n = 70, significant decreases of BMD, T-score and Z-score as well as the higher incidence of new bone fractures were recorded. Conclusion. ELF-PEMF could be a convenient and safe non-pharmacological therapeutic strategy for fracture prevention in nephrology practices.

  18. The fluid mechanics of root canal irrigation.

    Science.gov (United States)

    Gulabivala, K; Ng, Y-L; Gilbertson, M; Eames, I

    2010-12-01

    Root canal treatment is a common dental operation aimed at removing the contents of the geometrically complex canal chambers within teeth; its purpose is to remove diseased or infected tissue. The complex chamber is first enlarged and shaped by instruments to a size sufficient to deliver antibacterial fluids. These irrigants help to dissolve dying tissue, disinfect the canal walls and space and flush out debris. The effectiveness of the procedure is limited by access to the canal terminus. Endodontic research is focused on finding the instruments and clinical procedures that might improve success rates by more effectively reaching the apical anatomy. The individual factors affecting treatment outcome have not been unequivocally deciphered, partly because of the difficulty in isolating them and in making the link between simplified, general experimental models and the complex biological objects that are teeth. Explicitly considering the physical processes within the root canal can contribute to the resolution of these problems. The central problem is one of fluid motion in a confined geometry, which makes the dispersion and mixing of irrigant more difficult because of the absence of turbulence over much of the canal volume. The effects of treatments can be understood through the use of scale models, mathematical modelling and numerical computations. A particular concern in treatment is that caustic irrigant may penetrate beyond the root canal, causing chemical damage to the jawbone. In fact, a stagnation plane exists beyond the needle tip, which the irrigant cannot penetrate. The goal is therefore to shift the stagnation plane apically to be coincident with the canal terminus without extending beyond it. Needle design may solve some of the problems but the best design for irrigant penetration conflicts with that for optimal removal of the bacterial biofilm from the canal wall. Both irrigant penetration and biofilm removal may be improved through canal fluid

  19. The fluid mechanics of root canal irrigation

    International Nuclear Information System (INIS)

    Gulabivala, K; Ng, Y-L; Gilbertson, M; Eames, I

    2010-01-01

    Root canal treatment is a common dental operation aimed at removing the contents of the geometrically complex canal chambers within teeth; its purpose is to remove diseased or infected tissue. The complex chamber is first enlarged and shaped by instruments to a size sufficient to deliver antibacterial fluids. These irrigants help to dissolve dying tissue, disinfect the canal walls and space and flush out debris. The effectiveness of the procedure is limited by access to the canal terminus. Endodontic research is focused on finding the instruments and clinical procedures that might improve success rates by more effectively reaching the apical anatomy. The individual factors affecting treatment outcome have not been unequivocally deciphered, partly because of the difficulty in isolating them and in making the link between simplified, general experimental models and the complex biological objects that are teeth. Explicitly considering the physical processes within the root canal can contribute to the resolution of these problems. The central problem is one of fluid motion in a confined geometry, which makes the dispersion and mixing of irrigant more difficult because of the absence of turbulence over much of the canal volume. The effects of treatments can be understood through the use of scale models, mathematical modelling and numerical computations. A particular concern in treatment is that caustic irrigant may penetrate beyond the root canal, causing chemical damage to the jawbone. In fact, a stagnation plane exists beyond the needle tip, which the irrigant cannot penetrate. The goal is therefore to shift the stagnation plane apically to be coincident with the canal terminus without extending beyond it. Needle design may solve some of the problems but the best design for irrigant penetration conflicts with that for optimal removal of the bacterial biofilm from the canal wall. Both irrigant penetration and biofilm removal may be improved through canal fluid

  20. Irrigation and fertilization effects on Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Damage levels and pupal weight in an intensively-managed pine plantation.

    Energy Technology Data Exchange (ETDEWEB)

    Coyle, David, R.; Nowak, John, T.; Fettig, Christopher, J.

    2003-10-01

    The widespread application of intensive forest management practices throughout the southeastern U.S. has increased loblolly pine, Pinus taeda L., yields and shortened conventional rotation lengths. Fluctuations in Nantucket pine tip moth, Rhyacionia frustrana (Comstock), population density and subsequent damage levels have been linked to variations in management intensity. We examined the effects of two practices, irrigation and fertilization, on R. frustrana damage levels and pupal weights in an intensively-managed P. taeda plantation in South Carolina. Trees received intensive weed control and one of the following treatments; irrigation only. fertilization only, irrigation + fertilization, or control. Mean whole-tree tip moth damage levels ranged from <1 to 48% during this study. Damage levels differed significantly among treatments in two tip moth generations in 2001, but not 2000. Pupal weight was significantly heavier in fertilization compared to the irrigation treatment in 2000, but no significant differences were observed in 2001. Tree diameter. height. and aboveground volume were significantly greater in the irrigation + fertilization than in the irrigation treatment after two growing seasons. Our data suggest that intensive management practices that include irrigation and fertilization do not consistently increase R. frustrana damage levels and pupal weights as is commonly believed. However, tip moth suppression efforts in areas adjacent to our study may have partially reduced the potential impacts of R. frustrana on this experiment.

  1. Gas exchange in ‘BRS Princesa’ banana (Musa spp. under partial rootzone drying irrigation in the north of Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Marcelo Rocha dos Santos

    2017-07-01

    Full Text Available This research aimed to evaluate physiological characteristics of 'BRS Princesa' banana under Partial Rootzone Drying irrigation, PRD. The five treatments, 1 - 50% of reduction in water depth (WD with a frequency alternation of irrigation side (FA of seven days during the whole production cycle; 2 - 50% of WD and FA of 14 days in the cycle; 3 - 50% of WD and FA of 21 days; 4 - 50% of WD with a fixed irrigation (only one lateral line on one side of the plant; and 5 - full irrigation (two lateral lines with open shutoff valve throughout the cycle, they were arranged in a randomized block design with five replicates. There is a reduction in photosynthetic rates and water use efficiency as a result of enzymatic impairment or stomatal closure, due to the increased of leaf temperature. The stomatal conductance - gs was lower in plants irrigated with 50% of ETc with fixed irrigation in one side of the plant. Even with water deficit in the soil, using the PRD with 50% of ETc, Photosynthesis - A Transpiration - E; Leaf temperature - Tleaf, internal concentration of CO2 - Ci; stomatal conductance - gs; photosynthetically active radiation - Qleaf; carboxylation efficiency - A/Ci; Quantum efficiency of Photosynthesis - A/Qleaf; and instantaneous water use efficiency - WUE 'BRS Princesa' banana were similar among strategies, highlighting the possibility of use of the irrigation management technique with PRD, saving water, and no physiological changes in the plants.

  2. Lung density

    DEFF Research Database (Denmark)

    Garnett, E S; Webber, C E; Coates, G

    1977-01-01

    The density of a defined volume of the human lung can be measured in vivo by a new noninvasive technique. A beam of gamma-rays is directed at the lung and, by measuring the scattered gamma-rays, lung density is calculated. The density in the lower lobe of the right lung in normal man during quiet...... breathing in the sitting position ranged from 0.25 to 0.37 g.cm-3. Subnormal values were found in patients with emphsema. In patients with pulmonary congestion and edema, lung density values ranged from 0.33 to 0.93 g.cm-3. The lung density measurement correlated well with the findings in chest radiographs...... but the lung density values were more sensitive indices. This was particularly evident in serial observations of individual patients....

  3. Assessing hydrological drought risk for the irrigation sector in future climate scenarios: lessons learned from the Apulia case study (Italy)

    Science.gov (United States)

    Critto, Andrea; Torresan, Silvia; Ronco, Paolo; Zennaro, Federica; Santini, Monia; Trabucco, Antonio; Marcomini, Antonio

    2016-04-01

    Climate change is already affecting the frequency of drought events which may threaten the current stocks of water resources and thus the availability of freshwater for the irrigation. The achievement of a sustainable equilibrium between the availability of water resources and the irrigation demand is essentially related to the planning and implementation of evidence-based adaptation strategies and actions. In this sense, the improvement (of existing) and the development of (new) appropriate risk assessment methods and tools to evaluate the impact of drought events on irrigated crops is fundamental in order to assure that the agricultural yields are appropriate to meet the current and future food and market demand. This study evaluates the risk of hydrological drought on the irrigated agronomic compartment of Apulia, a semi-arid region in Southern Italy. We applied a stepwise Regional Risk Assessment (RRA) procedure, based on the consecutive analysis of hazards, exposure, vulnerability and risks, integrating the qualitative and quantitative available information. Future climate projections for the timeframes 2021-2050 and 2041-2070 were provided by COSMO-CLM under the radiative forcing RCP4.5 and RCP8.5. The run-off feeding the water stocks of the most important irrigation reservoirs in Apulia was then modeled with Arc-SWAT. Hence, the hazard analysis was carried out in order to estimate the degree of fulfillment of actual irrigation demand satisfied by water supply of different reservoirs in future scenarios. Vulnerability of exposed irrigated crops was evaluated depending on three factors accounting for crop yield variation vs water stress, water losses along the irrigation network, diversification of water supply. Resulting risk and vulnerability maps allowed: the identification of Reclamation Consortia at higher risk of not fulfilling their future irrigation demand (e.g. Capitanata Reclamation Consortia in RCP8.5 2041-2070 scenario); the ranking of most

  4. Control system design for concrete irrigation channels

    OpenAIRE

    Strecker, Timm; Aamo, Ole Morten; Cantoni, Michael

    2017-01-01

    Concrete channels find use at the periphery of irrigation networks, for expansion and to replace small earthen channels given the relative ease of maintenance and elimination of seepage losses. In design, it is important to account for control system performance when dimensioning the channel infrastructure. In this paper, the design of a distributed controller is investigated in terms managing water-levels, and thereby the depth profile (i.e., amount of concrete) needed to support peak flow l...

  5. Coolidge solar powered irrigation pumping project

    Science.gov (United States)

    Larson, D. L.

    1980-01-01

    A 150 kW solar thermal electric power plant which includes over 2100 square meters of parabolic trough type collectors and an organic Rankine cycle turbine engine was constructed on an irrigated farm. The plant is interconnected with the electrical utility grid. Operation is providing an evaluation of equipment performance and operating and maintenance requirements as well as the desirability of an on farm location.

  6. Irrigation port hydration in phacoemulsification surgery

    Directory of Open Access Journals (Sweden)

    Suzuki H

    2018-01-01

    Full Text Available Hisaharu Suzuki,1 Yoichiro Masuda,2 Yuki Hamajima,1 Hiroshi Takahashi3 1Department of Ophthalmology, Nippon Medical School Musashikosugi Hospital, Kawasaki City, Kanagawa, 2Department of Ophthalmology, The Jikei University, Katsushika Medical Center, Tokyo, 3Department of Ophthalmology, Nippon Medical School, Tokyo, Japan Background: In most cases, hydration is performed by water injection into the stromal tissue with a needle. The technique is simple, however it is sometimes troublesome.Purpose: We describe a simple technique for hydrating the corneal stroma in cataract surgery using an irrigation port.Patients and methods: The technique began by pushing the irrigation port against the corneal stroma for a few seconds during phacoemulsification, which generated edema in the corneal incision that subsequently prevented leakage. This procedure is called the hydration using irrigation port (HYUIP technique. A total of 60 eyes were randomized and placed in two groups, 30 eyes underwent surgeries using the HYUIP technique (HYUIP group and 30 eyes underwent surgeries without the HYUIP technique (control. The three points evaluated during each surgery included 1 the occurrence of anterior chamber collapse during the pulling out of the I/A tip after inserting the intraocular lens, 2 the need for conventional hydration, and 3 watertight completion at the end stage of surgery.Results: The anterior chamber collapse and the need for conventional hydration were significantly smaller in the HYUIP group compared to the control group. Regarding the self-sealing completion, no significant difference was observed between the two groups.Conclusion: The HYUIP technique is an effective method for creating self-sealing wound. In addition, this technique helps to prevent anterior chamber collapse. Keywords: cataract surgery, hydration, irrigation and aspiration, phacoemulsification, wound, self-sealing 

  7. Antimicrobial Irrigants in the Endodontic Therapy

    OpenAIRE

    Iqbal, Azhar

    2012-01-01

    This paper highlights the importance of root canal disinfection. It discusses the different endodontic irrigants available and comments on how these can be used most effectively. Eliminating bacteria from the root canal system is an essential stage in endodontic therapy. An objective of endodontic treatment is removal of diseased tissue, elimination of bacteria from the canal system and prevention of recontamination. (1) Disinfection of the root canal system, as part of endodontic therapy, by...

  8. Online decision support system for surface irrigation management

    Science.gov (United States)

    Wang, Wenchao; Cui, Yuanlai

    2017-04-01

    Irrigation has played an important role in agricultural production. Irrigation decision support system is developed for irrigation water management, which can raise irrigation efficiency with few added engineering services. An online irrigation decision support system (OIDSS), in consist of in-field sensors and central computer system, is designed for surface irrigation management in large irrigation district. Many functions have acquired in OIDSS, such as data acquisition and detection, real-time irrigation forecast, water allocation decision and irrigation information management. The OIDSS contains four parts: Data acquisition terminals, Web server, Client browser and Communication system. Data acquisition terminals are designed to measure paddy water level, soil water content in dry land, ponds water level, underground water level, and canals water level. A web server is responsible for collecting meteorological data, weather forecast data, the real-time field data, and manager's feedback data. Water allocation decisions are made in the web server. Client browser is responsible for friendly displaying, interacting with managers, and collecting managers' irrigation intention. Communication system includes internet and the GPRS network used by monitoring stations. The OIDSS's model is based on water balance approach for both lowland paddy and upland crops. Considering basic database of different crops water demands in the whole growth stages and irrigation system engineering information, the OIDSS can make efficient decision of water allocation with the help of real-time field water detection and weather forecast. This system uses technical methods to reduce requirements of user's specialized knowledge and can also take user's managerial experience into account. As the system is developed by the Browser/Server model, it is possible to make full use of the internet resources, to facilitate users at any place where internet exists. The OIDSS has been applied in

  9. Comparison and analysis of empirical equations for soil heat flux for different cropping systems and irrigation methods

    Science.gov (United States)

    Irmak, A.; Singh, Ramesh K.; Walter-Shea, Elizabeth; Verma, S.B.; Suyker, A.E.

    2011-01-01

    We evaluated the performance of four models for estimating soil heat flux density (G) in maize (Zea mays L.) and soybean (Glycine max L.) fields under different irrigation methods (center-pivot irrigated fields at Mead, Nebraska, and subsurface drip irrigated field at Clay Center, Nebraska) and rainfed conditions at Mead. The model estimates were compared against measurements made during growing seasons of 2003, 2004, and 2005 at Mead and during 2005, 2006, and 2007 at Clay Center. We observed a strong relationship between the G and net radiation (Rn) ratio (G/Rn) and the normalized difference vegetation index (NDVI). When a significant portion of the ground was bare soil, G/Rn ranged from 0.15 to 0.30 and decreased with increasing NDVI. In contrast to the NDVI progression, the G/Rn ratio decreased with crop growth and development. The G/Rn ratio for subsurface drip irrigated crops was smaller than for the center-pivot irrigated crops. The seasonal average G was 13.1%, 15.2%, 10.9%, and 12.8% of Rn for irrigated maize, rainfed maize, irrigated soybean, and rainfed soybean, respectively. Statistical analyses of the performance of the four models showed a wide range of variation in G estimation. The root mean square error (RMSE) of predictions ranged from 15 to 81.3 W m-2. Based on the wide range of RMSE, it is recommended that local calibration of the models should be carried out for remote estimation of soil heat flux.

  10. Use of Dehydrated Agar to Estimate Microbial Water Quality for Horticulture Irrigation.

    Science.gov (United States)

    Meador, Dustin P; Fisher, Paul R; Guy, Charles L; Harmon, Philip F; Peres, Natalia A; Teplitski, Max

    2016-07-01

    Petrifilms are dehydrated agar culture plates that have been used to quantify colony forming units (CFU) mL of either aerobic bacteria (Petrifilm-AC) or fungus (Petrifilm-YM), depending on substrate composition. Microbes in irrigation systems can indicate biofilm risk and potential clogging of irrigation emitters. The research objective was to compare counts on Petrifilms versus traditional, hydrated-agar plates using samples collected from recirculated irrigation waters and cultures of isolated known species. The estimated count (in CFU mL) from a recirculated irrigation sample after 7 d of incubation on Petrifilm-YM was only 5.5% of the count quantified using sabouraud dextrose agar (SDA) with chloramphenicol after 14 d. In a separate experiment with a known species, Petrifilm-YM did not successfully culture zoospores of . Isolates of viable zoospores were cultured successfully on potato-dextrose agar (PDA), with comparable counts with a vegetable juice medium supplemented with the antibiotics pimaricin, ampicillin, rifamycin, pentochloronitrobenzene and hymexazol (PARP-H). The quantification of pv. Begoniaceae on Petrifilm-AC was not significantly different ( < 0.05) than on PDA, but was lower than on Reasoner and Goldrich agar (R2A) or with a hemocytometer. The current formulation of Petrifilm-YM is unlikely to be a useful monitoring method for plant pathogens in irrigation water because of the inability to successfully culture oomycetes. However, Petrifilm-AC was an effective method to quantify bacteria and can provide an easy-to-use on-farm tool to monitor biofilm risk and microbial density. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  11. Irrigation and fruit canopy position modify oil quality of olive trees (cv. Frantoio).

    Science.gov (United States)

    Caruso, Giovanni; Gucci, Riccardo; Sifola, Maria Isabella; Selvaggini, Roberto; Urbani, Stefania; Esposto, Sonia; Taticchi, Agnese; Servili, Maurizio

    2017-08-01

    Fruit development and oil quality in Olea europaea L. are strongly influenced by both light and water availability. In the present study, the simultaneous effects of light environment and irrigation on fruit characteristics and oil quality were studied in a high-density orchard over two consecutive years. Olive fruits were harvested from three canopy positions (intercepting approximately 64%, 42% and 30% of above canopy radiation) of fully-productive trees subjected to full, deficit or complementary irrigation. Fruits receiving 61-67% of above canopy radiation showed the highest fruit weight, mesocarp oil content and maturation index, whereas those intercepting only 27-33% showed the lowest values. Palmitoleic and linoleic acids increased in oils obtained from fruits exposed to high light levels, whereas oleic acid and the oleic-linoleic acid ratio decreased. Neither canopy position, nor irrigation affected K 232 , K 270 , ΔK and the concentration of lignan in virgin olive oils (VOOs). Total phenols, 3,4-DHPEA-EDA [2-(3,4-hydroxyphenyl)ethyl (3S,4E)-4-formyl-3-(2-oxoethyl)hex-4-enoate] and p-HPEA-EDA (decarboxymethyl ligstroside-aglycone) increased in VOOs produced from fruits harvested from the top of the canopy, whereas full irrigation decreased total phenols and 3,4-DHPEA-EDA concentrations with respect to the complementary irrigation treatment. Light and water availability are crucial not only for tree productivity, but also they clearly affect olive oil quality. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  12. Selectivity and weed control efficacy of some herbicides applied to sprinkler irrigated rice (Oryza sativa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Cavero, J; Zaragoza, C; Cirujeda, A; Anzalone, A; Faci, J M; Blanco, O

    2011-07-01

    Sprinkler irrigation can reduce the irrigation water needed to grow rice. However, most available information on weed control with herbicides is related to flood irrigated rice because this is the main growing method. Field experiments were conducted at Zaragoza (Spain) during two years to study weed control and tolerance of sprinkler irrigated rice to several herbicides. The main weeds were Atriplex prostrata Boucher ex DC., Cyperus rotundus L., Echinochloa crus-galli (L.) Beauv. and Sonchus oleraceus L. Rice cv Guadiamar was tolerant to preemergence (PRE) application of clomazone at 0.36 kg ha{sup -}1 and oxadiazon at 0.5 kg ha{sup -}1. PRE application of pendimethalin at 1.32 kg ha{sup -}1 combined with clomazone at 0.36 kg ha{sup -}1 decreased rice yield. Postemergence (POST) application of bentazon at 1.6 kg ha{sup -}1 + MCPA at 0.25 kg ha{sup -}1 did not injure rice but POST application of azimsulfuron at 0.025 kg ha{sup -}1 produced visual crop injury. Only treatments that controlled grassy weeds since rice was planted and by more than 80% at harvest time lead to acceptable rice yield (> 5,000 kg ha{sup -}1). Clomazone applied PRE at 0.36 kg ha{sup -}1 provided good control of grassy weeds (> 80%) and the highest rice yield, so it is recommended as a selective and efficacious PRE treatment for weed control of annual weeds in sprinkler irrigated rice. The perennial purple nutsedge was difficult to control at high plant densities (> 150 plants m{sup -}2) and the recommended herbicide is azimsulfuron applied at POST at 0.02 kg ha{sup -}1. (Author) 37 refs.

  13. On the control of irrigation through soil moisture measurement using a neutron depth probe in horizontal subsurface measuring circuits

    International Nuclear Information System (INIS)

    Schaecke, B.; Schaecke, E.

    1977-01-01

    An outline is given of the advantages inherent in soil moisture measurement by means of a neutron probe in horizontal subsurface measuring circuits for irrigation control. Preliminary experience for the setting up of a field calibration curve and for practical measurement are submitted. This technique includes the following advantages: almost complete covering of the upper soil range which is of interest to irrigation control; good measuring density; suitable distribution of measuring points per unit area; possibility of continuous probe passage; optimal repeatability of measurements; exploration of a unit area with but few measuring circuits; no obstacles to tillage, drilling, intercultivation and harvest operations; and complete conservation of crop and plot which is not reached with any other soil moisture measurement technique so far available. Making use of the above advantages, the new technique allows automatic irrigation control with only one neutron depth probe. (author)

  14. Root distribution pattern of triticale varieties under irrigated and unirrigated conditions using 32P plant injection technique

    International Nuclear Information System (INIS)

    Mahajan, J.P.; Soni, B.K.; Bhargava, B.S.

    1977-01-01

    A study on the root distribution pattern of four triticale varieties (6TA-204-3, 6TA-204-4, S-520 and S-411) under irrigated and unirrigated conditions showed that in general, there was a more profused root system in irrigated conditions than in the unirrigated ones. The lateral root distribution was adversely affected under unirrigated conditions. Root density of different varieties, in a soil segment of 15 cm diameter and 48 cm depth grown under unirrigated conditions, was in the following order : S-520 > 6 TA-204-3 > 6 TA-204-4 > S-411 while under irrigated conditions the order was : 6 TA-204-3 > S-520 > 6 TA-204-4 > S-411. (author)

  15. Root Zone Sensors for Irrigation Management in Intensive Agriculture

    Directory of Open Access Journals (Sweden)

    Jochen Hemming

    2009-04-01

    Full Text Available Crop irrigation uses more than 70% of the world’s water, and thus, improving irrigation efficiency is decisive to sustain the food demand from a fast-growing world population. This objective may be accomplished by cultivating more water-efficient crop species and/or through the application of efficient irrigation systems, which includes the implementation of a suitable method for precise scheduling. At the farm level, irrigation is generally scheduled based on the grower’s experience or on the determination of soil water balance (weather-based method. An alternative approach entails the measurement of soil water status. Expensive and sophisticated root zone sensors (RZS, such as neutron probes, are available for the use of soil and plant scientists, while cheap and practical devices are needed for irrigation management in commercial crops. The paper illustrates the main features of RZS’ (for both soil moisture and salinity marketed for the irrigation industry and discusses how such sensors may be integrated in a wireless network for computer-controlled irrigation and used for innovative irrigation strategies, such as deficit or dual-water irrigation. The paper also consider the main results of recent or current research works conducted by the authors in Tuscany (Italy on the irrigation management of container-grown ornamental plants, which is an important agricultural sector in Italy.

  16. Irrigation Capability Evaluation of Illushi Floodplain, Edo State, Nigeria

    Directory of Open Access Journals (Sweden)

    A.S. Umweni

    2014-06-01

    Full Text Available Many irrigation projects, especially in the developing tropical regions, are embarked upon without any land capability assessment, resulting in avoidable and undesirable ecological consequences. The aim of this study is to assess the irrigation capability potentials of the soils of a rice growing Illushi/Ega community in Edo State of Nigeria. Soils of Illushi/Ega (200 ha were studied to establish their irrigation capabilities. Water samples were collected from the rivers within and near the sites at the proposed points of intake structures and analyzed for salinity (ECw, permeability (SAR and ion toxicity [Chlorine (Cl and Boron (B]. Gravity irrigation suitability assessment was carried out following the guidelines of the United States Bureau for Land Reclamation (USBR, 1953 and FAO (1979. Results showed that about 5.5 % of the land was non-irrigable, 11.5 % was marginally irrigable, 30.5% was moderately irrigable and 52.5 % highly irrigable.Thus about 83 % of the total land area was found to be irrigable. The results of analyses of irrigation water [ECw, SAR and Cl and B (ion toxicity problems in water sources were 0.1 – 0.7 dS m-1, 1.2 – 1.7, 0.6 – 1.8 cmol kg-1 and 0.5 – 0.7 mg kg-1] also show that there is no indication of salinity or ion toxicity problem.

  17. Review of root canal irrigant delivery techniques and devices

    Directory of Open Access Journals (Sweden)

    Yeon-Jee Yoo

    2011-05-01

    Full Text Available Introduction Eliminating the residual debris and bacteria in the root canal system is one of the main purposes of the endodontic treatment. However, the complexity on the anatomy of the root canal system makes it difficult to eliminate the bacterial biofilm existing along the root canal surface and necrotic pulp tissue by mechanical instrumentation and chemical irrigation. Recently, more effective irrigant delivery systems for root canal irrigation have been developed. The purpose of this review was to present an overview of root canal irrigant delivery techniques and devices available in endodontics. Review The contents of this paper include as follows; - syringe-needle irrigation, manual dynamic irrigation, brushes - sonic and ultrasonic irrigation, passive ultrasonic irrigation, rotary brush, RinsEndo, EndoVac, Laser Conclusion Though technological advances during the last decade have brought to fruition new agitation devices that rely on various mechanisms, there are few evidence based study to correlate the clinical efficacy of these devices with improved outcomes except syringe irrigation with needle and ultrasonic irrigation. The clinicians should try their best efforts to deliver antimicrobial and tissue solvent solutions in predictable volumes safely to working length.

  18. Rice Photosynthetic Productivity and PSII Photochemistry under Nonflooded Irrigation

    Directory of Open Access Journals (Sweden)

    Haibing He

    2014-01-01

    Full Text Available Nonflooded irrigation is an important water-saving rice cultivation technology, but little is known on its photosynthetic mechanism. The aims of this work were to investigate photosynthetic characteristics of rice during grain filling stage under three nonflooded irrigation treatments: furrow irrigation with plastic mulching (FIM, furrow irrigation with nonmulching (FIN, and drip irrigation with plastic mulching (DI. Compared with the conventional flooding (CF treatment, those grown in the nonflooded irrigation treatments showed lower net photosynthetic rate (PN, lower maximum quantum yield (Fv/Fm, and lower effective quantum yield of PSII photochemistry (ΦPSII. And the poor photosynthetic characteristics in the nonflooded irrigation treatments were mainly attributed to the low total nitrogen content (TNC. Under non-flooded irrigation, the PN, Fv/Fm, and ΦPSII significantly decreased with a reduction in the soil water potential, but these parameters were rapidly recovered in the DI and FIM treatments when supplementary irrigation was applied. Moreover, The DI treatment always had higher photosynthetic productivity than the FIM and FIN treatments. Grain yield, matter translocation, and dry matter post-anthesis (DMPA were the highest in the CF treatment, followed by the DI, FIM, and FIN treatments in turn. In conclusion, increasing nitrogen content in leaf of rice plants could be a key factor to improve photosynthetic capacity in nonflooded irrigation.

  19. Predicting deep percolation with eddy covariance under mulch drip irrigation

    Science.gov (United States)

    Ming, Guanghui; Tian, Fuqiang; Hu, Hongchang

    2016-04-01

    Water is essential for the agricultural development and ecological sustainability of the arid and semi-arid oasis with rare precipitation input and high evaporation demand. Deep percolation (DP) defined as excess irrigation water percolating below the plant root zone will reduce irrigation water use efficiency (WUE). But the DP was often ignored in mulch drip irrigation (MDI) which has reached the area of 1.6 million hectares in Xinjiang, the northwest of China. In this study DP experiments were conducted at an agricultural experiment station located within an irrigation district in the Tarim River Basin for four cotton growing periods. First it was detected the irrigation water infiltrated into the soil layers below 100cm and the groundwater level responded to the irrigation events well. Then DP below 100cm soil layers was calculated using the soil water balance method with the aid of eddy covariance (with the energy balance closure of 0.72). The negative DP (groundwater contribution to the crop-water use through capillary rising) at the seedling and harvesting stages can reach 77mm and has a good negative correlation with the groundwater level and positive correlation with potential evaporation. During the drip irrigation stage approximately 45% of the irrigation became DP and resulted in the low irrigation WUE of 0.6. The DP can be 164mm to 270mm per year which was positive linearly correlated to irrigation depth and negative linear correlated to irrigation interval. It is better to establish the irrigation schedule with small irrigation depth and given frequently to reduce deep percolation and meet crop needs.

  20. Anisotropic dynamic mass density for fluidsolid composites

    KAUST Repository

    Wu, Ying; Mei, Jun; Sheng, Ping

    2012-01-01

    By taking the low frequency limit of multiple-scattering theory, we obtain the dynamic effective mass density of fluidsolid composites with a two-dimensional rectangular lattice structure. The anisotropic mass density can be described by an angle

  1. Comparative study of irrigation water use and groundwater recharge under various irrigation schemes in an agricultural region, central Taiwan

    Science.gov (United States)

    Chen, Shih-Kai; Jang, Cheng-Shin; Tsai, Cheng-Bin

    2016-04-01

    The risk of rice production has increased notably due to climate change in Taiwan. To respond to growing agricultural water shortage without affecting normal food production in the future, the application of water-saving irrigation will be a substantial resolution. However, the adoption of water-saving irrigation may result in the reducing of groundwater recharge because continuous flooding in the paddy fields could be regarded as an important source for groundwater recharge. The aim of this study was to evaluate the irrigation water-saving benefit and groundwater recharge deficit when adopting the System of Rice Intensification, known as SRI methodology, in the Choushui River alluvial fan (the largest groundwater pumping and the most important rice-cropping region in central Taiwan). The three-dimensional finite element groundwater model, FEMWATER, was applied to simulate the infiltration process and groundwater recharge under SRI methodology and traditional irrigation schemes including continuous irrigation, and rotational irrigation in two rice-crop periods with hydro-climatic data of 2013. The irrigation water use was then calculated by water balance. The results showed that groundwater recharge amount of SRI methodology was slightly lower than those of traditional irrigation schemes, reduced 3.6% and 1.6% in the first crop period, and reduced 3.2% and 1.6% in the second crop period, compared with continuous irrigation and rotational irrigation, respectively. However, the SRI methodology achieved notably water-saving benefit compared to the disadvantage of reducing the groundwater recharge amount. The field irrigation requirement amount of SRI methodology was significantly lower than those of traditional irrigation schemes, saving 37% and 20% of irrigation water in the first crop period, and saving 53% and 35% in the second crop period, compared with continuous irrigation and rotational irrigation, respectively. Therefore, the amount of groundwater pumping for

  2. Irrigation-based livelihood challenges and opportunities : a gendered technology of irrigation development intervention in the Lower Moshi irrigation scheme Tanzania

    NARCIS (Netherlands)

    Kissawike, K.

    2008-01-01

    This thesis is a study of a modernised irrigation scheme in Tanzania. It aims to
    understand how irrigation and agricultural technologies have interacted with local
    society to transform production, paying particular attention to gender relations and
    changes for women farmers. The

  3. Reducing microbial contamination on wastewater-irrigated lettuce by cessation of irrigation before harvesting

    DEFF Research Database (Denmark)

    Keraita, Bernard; Konradsen, Flemming; Drechsel, Pay

    2007-01-01

    OBJECTIVE: To assess the effectiveness of cessation of irrigation before harvesting in reducing microbial contamination of lettuce irrigated with wastewater in urban vegetable farming in Ghana. METHODS: Assessment was done under actual field conditions with urban vegetable farmers in Ghana. Trials...... were arranged in completely randomized block design and done both in the dry and wet seasons. Seven hundred and twenty-six lettuce samples and 36 water samples were analysed for thermotolerant coliforms and helminth eggs. RESULTS: On average, 0.65 log units for indicator thermotolerant coliforms and 0.......4 helminth eggs per 100 g of lettuce were removed on each non-irrigated day from lettuce in the dry season. This corresponded to a daily loss of 1.4 tonnes/ha of fresh weight of lettuce. As an input for exposure analysis to make risk estimates, the decay coefficient, k, for thermotolerant coliforms was 0...

  4. Energy performance of sprinkler irrigated maize, wheat and sunflower in Vigia irrigation district

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Sandra; Rodrigues, Goncalo Caleia; Paredes, Paula; Pereira, Luis S. [Centro de Engenharia dos Biossistemas (CEER/ISA), Lisboa (Portugal)], E-mail: lspereira@isa.utl.pt

    2008-07-01

    The energy potential of a crop may be evaluated through life cycle assessment methodologies. These refer to the computation of the crop's energy balance and other related indicators, such as the energy ratio and the energetic efficiency, that may be used as to assess how a given irrigated crop may be used for production of biofuel. This study concerns sprinkler irrigated sunflower, wheat and maize crops using data relative to the campaign of 2007 in the Vigia Irrigation District, Alentejo. A model was developed and various scenarios were considered. The modelling results lead to the conclusion that the maize crop is the most efficient in producing energy and sunflower is the least one for all the alternative scenarios considered. (author)

  5. The real water consumption of orange trees irrigated by reused water in tunisia

    Energy Technology Data Exchange (ETDEWEB)

    Zouhaier, M C [Center de recherche du Genie Rural B.P. No. 10-2080 Ariana (Tunisia)

    1995-10-01

    Our research experiments, have been conducted in the experiment station of `Oued souhil` situated under semi-arid climate in tunisia. We have studied the real water consumption of orange trees irrigated by reused water compared the results with trees using water from well. For measuring the different parameters, to determine soil humidity and the soil apparent density, we have used respectively neutron lead `Neutron probe` and radiation gamma instruments. However, the experiments results conducted for 7 years from 1987 to 1993 - allowed the evaluation of the read consumption of orange trees using reused water and well water and the production quantity. The effect of using the two different quality of water with different irrigation systems have been also studied. 6 figs., 4 tabs.

  6. The real water consumption of orange trees irrigated by reused water in tunisia

    International Nuclear Information System (INIS)

    Zouhaier, M.C.

    1995-01-01

    Our research experiments, have been conducted in the experiment station of 'Oued souhil' situated under semi-arid climate in tunisia. We have studied the real water consumption of orange trees irrigated by reused water compared the results with trees using water from well. For measuring the different parameters, to determine soil humidity and the soil apparent density, we have used respectively neutron lead 'Neutron probe' and radiation gamma instruments. However, the experiments results conducted for 7 years from 1987 to 1993 - allowed the evaluation of the read consumption of orange trees using reused water and well water and the production quantity. The effect of using the two different quality of water with different irrigation systems have been also studied. 6 figs., 4 tabs

  7. Adult anopheline ecology and malaria transmission in irrigated areas of South Punjab, Pakistan

    DEFF Research Database (Denmark)

    Herrel, N; Amerasinghe, F P; Ensink, J

    2004-01-01

    Surface irrigation in the Punjab province of Pakistan has been carried out on a large scale since the development of the Indus Basin Irrigation System in the late 19th century. The objective of our study was to understand how the population dynamics of adult anopheline mosquitoes (Diptera....... Mosquitoes were collected from bedrooms using the pyrethroid spraycatch method and from vegetation and animal sheds using backpack aspirators. Overall, Anopheles subpictus Grassi sensu lato predominated (55.6%), followed by An. stephensi Liston s.l. (41.4%), An. culicifacies Giles s.l. (2.0%), An....... pulcherrimus Theobald (1.0%) and An. peditaeniatus Leicester (0.1%). Most mosquitoes (98.8%) were collected from indoor resting-sites whereas collections from potential resting-sites outdoors accounted for only 1.2% of total anopheline densities, confirming the endophilic behaviour of anophelines in Pakistan...

  8. Impacts of Irrigation on the Heat Fluxes and Near-Surface Temperature in an Inland Irrigation Area of Northern China

    Directory of Open Access Journals (Sweden)

    Li Jiang

    2014-03-01

    Full Text Available Irrigated agriculture has the potential to alter regional to global climate significantly. We investigate how irrigation will affect regional climate in the future in an inland irrigation area of northern China, focusing on its effects on heat fluxes and near-surface temperature. Using the Weather Research and Forecasting (WRF model, we compare simulations among three land cover scenarios: the control scenario (CON, the irrigation scenario (IRR, and the irrigated cropland expansion scenario (ICE. Our results show that the surface energy budgets and temperature are sensitive to changes in the extent and spatial pattern of irrigated land. Conversion to irrigated agriculture at the contemporary scale leads to an increase in annual mean latent heat fluxes of 12.10 W m−2, a decrease in annual mean sensible heat fluxes of 8.85 W m−2, and a decrease in annual mean temperature of 1.3 °C across the study region. Further expansion of irrigated land increases annual mean latent heat fluxes by 18.08 W m−2, decreases annual mean sensible heat fluxes by 12.31 W m−2, and decreases annual mean temperature by 1.7 °C. Our simulated effects of irrigation show that changes in land use management such as irrigation can be an important component of climate change and need to be considered together with greenhouse forcing in climate change assessments.

  9. Traditional Irrigation Management in Betmera-Hiwane, Ethiopia: The Main Peculiarities for the Persistence of Irrigation Practices

    Institute of Scientific and Technical Information of China (English)

    Solomon Habtu; Kitamura Yoshinobu

    2006-01-01

    Traditional irrigation, as part of the ancient agricultural practices in northern Ethiopia (Tigray), has persisted for long time since 500 B.C.,while many newly introduced irrigation projects have usually failed there. The main objective of this study is thus to investigate the peculiarities pertinent to irrigation management and those having contributed for the persistence of traditional irrigation practices for a long period of time. The experience gained from such areas can definitely help make irrigation management system of new irrigation schemes sustainable. Betmera-Hiwane, one of the ancient traditional irrigation areas in Tigray region, was selected for the field study. Direct observations through field visits accompanied by interviews to farmers, local officials, local knowledgeable individuals and higher officials were made. After analyzing the collected primary and secondary information, the main peculiarities that contributed to the persistence of traditional irrigation areas were identified, and they are: the presence of communally constructed local rules, locally designed hydraulic control structures, ownership feeling of the irrigators and accountability of water distributors to the irrigation management, the culture for mobilizing communal resources and the culture of self-initiating local water management strategies.

  10. Where Does the Irrigation Water Go? An Estimate of the Contribution of Irrigation to Precipitation Using MERRA

    Science.gov (United States)

    Wei, Jiangfeng; Dirmeyer, Paul A.; Wisser, Dominik; Bosilovich, Michael G.; Mocko, David M.

    2013-01-01

    Irrigation is an important human activity that may impact local and regional climate, but current climate model simulations and data assimilation systems generally do not explicitly include it. The European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-Analysis (ERA-Interim) shows more irrigation signal in surface evapotranspiration (ET) than the Modern-Era Retrospective Analysis for Research and Applications (MERRA) because ERA-Interim adjusts soil moisture according to the observed surface temperature and humidity while MERRA has no explicit consideration of irrigation at the surface. But, when compared with the results from a hydrological model with detailed considerations of agriculture, the ET from both reanalyses show large deficiencies in capturing the impact of irrigation. Here, a back-trajectory method is used to estimate the contribution of irrigation to precipitation over local and surrounding regions, using MERRA with observation-based corrections and added irrigation-caused ET increase from the hydrological model. Results show substantial contributions of irrigation to precipitation over heavily irrigated regions in Asia, but the precipitation increase is much less than the ET increase over most areas, indicating that irrigation could lead to water deficits over these regions. For the same increase in ET, precipitation increases are larger over wetter areas where convection is more easily triggered, but the percentage increase in precipitation is similar for different areas. There are substantial regional differences in the patterns of irrigation impact, but, for all the studied regions, the highest percentage contribution to precipitation is over local land.

  11. Irrigation and avifaunal change in coastal Northwest Mexico: has irrigated habit attracted threatened migratory species?

    Science.gov (United States)

    Grason, Emily; Navarro-Sigüenza, Adolfo G.

    2015-01-01

    Irrigation in desert ecosystems can either reduce or increase species diversity. Groundwater pumping often lowers water tables and reduces natural wetlands, whereas canal irrigation often creates mesic habitat, resulting in great increases in avian diversity from irrigation. Here we compare a dataset of potential natural vegetation to recent datasets from areal and satellite imagery to show that 60% of the land in the coastal plain of southern Sonora and northern Sinaloa lying below 200 m elevation has been converted by irrigation to more mesic habitats. We then use the record of bird specimens in the world’s museums from this same region of Mexico to examine the avian community before and after the development of extensive irrigation. In general these museum records show an increase in the abundance and diversity of breeding birds associated with mesic habitats. Although thorn forest birds have likely decreased in total numbers, most are common enough in the remaining thorn forest that collection records did not indicate their probable decline. Four migrants having most of their breeding ranges in the US or Canada, Yellow-billed Cuckoo, Cliff Swallow, Bell’s Vireo, and Orchard Oriole, apparently have increased dramatically as breeders in irrigated habitats of NW Mexico. Because these species have decreased or even largely disappeared as breeding birds in parts of the US or Canada, further research should assess whether their increases in new mesic habitats of NW Mexico are linked to their declines as breeding birds in Canada and the US For Bell’s Vireo recent specimens from Sinaloa suggest its new breeding population in NW Mexico may be composed partly of the endangered Least Bell’s Vireo. PMID:26312181

  12. Effects of soil texture and drought stress on the uptake of antibiotics and the internalization of Salmonella in lettuce following wastewater irrigation.

    Science.gov (United States)

    Zhang, Yuping; Sallach, J Brett; Hodges, Laurie; Snow, Daniel D; Bartelt-Hunt, Shannon L; Eskridge, Kent M; Li, Xu

    2016-01-01

    Treated wastewater is expected to be increasingly used as an alternative source of irrigation water in areas facing fresh water scarcity. Understanding the behaviors of contaminants from wastewater in soil and plants following irrigation is critical to assess and manage the risks associated with wastewater irrigation. The objective of this study was to evaluate the effects of soil texture and drought stress on the uptake of antibiotics and the internalization of human pathogens into lettuce through root uptake following wastewater irrigation. Lettuce grown in three soils with variability in soil texture (loam, sandy loam, and sand) and under different levels of water stress (no drought control, mild drought, and severe drought) were irrigated with synthetic wastewater containing three antibiotics (sulfamethoxazole, lincomycin and oxytetracycline) and one Salmonella strain a single time prior to harvest. Antibiotic uptake in lettuce was compound-specific and generally low. Only sulfamethoxazole was detected in lettuce with increasing uptake corresponding to increasing sand content in soil. Increased drought stress resulted in increased uptake of lincomycin and decreased uptake of oxytetracycline and sulfamethoxazole. The internalization of Salmonella was highly dependent on the concentration of the pathogen in irrigation water. Irrigation water containing 5 Log CFU/mL Salmonella resulted in limited incidence of internalization. When irrigation water contained 8 Log CFU/mL Salmonella, the internalization frequency was significantly higher in lettuce grown in sand than in loam (p = 0.009), and was significantly higher in lettuce exposed to severe drought than in unstressed lettuce (p = 0.049). This work demonstrated how environmental factors affected the risk of contaminant uptake by food crops following wastewater irrigation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Comparison of Manual and Automatic Irrigation of Pot Experiments

    DEFF Research Database (Denmark)

    Haahr, Vagner

    1975-01-01

    An air-lift principle for transport of water was adapted for automatic irrigation of experimental pots originally constructed for manual irrigation by the weighing method. The two irrigation techniques were compared in an experiment with increasing amounts of nitrogen fertilizer to spring barley....... Productions of grain and straw and chemical composition were almost the same after the two irrigation methods, and it was concluded that the laborious manual watering could be replaced by automatic irrigation. Comparison of the yield from individual plants in the pots showed a large difference between centre...... plants and border plants independent of irrigation principle. The increase in yield per pot with increasing N fertilization was at the highest N level caused only by an increase in yield of the border plants....

  14. Reform of irrigation management and investment policy in African development

    Directory of Open Access Journals (Sweden)

    KW Easter

    2004-11-01

    Full Text Available This paper examines the reform of water and irrigation management in Africa and compares it with similar reforms in Asia.  Several things are evident from the review.  First, Sub-Saharan Africa (SSA is at an earlier stage of irrigation development and reform than Asia.  Second, the articulated need for reform is much stronger in Asia than it is in SSA.  Third, the productivity of small-scale irrigated farms is significantly lower in SSA compared to Asia.  Thus any irrigation investment strategy in SSA should be different from Asia and focus on increasing small-farm productivity as well as small-scale irrigation projects.  Finally, all direct government irrigation investments should be done jointly with decisions regarding the type of project management.

  15. LOW COST SMART SOLAR POWERED AUTOMATIC IRRIGATION SYSTEM

    OpenAIRE

    Hinsermu Alemayehu*, Kena Likassa

    2016-01-01

    In developing countries Photovoltaic energy can find many applications in agriculture, providing electrical energy in various cases, particularly OFF grid and desert area. Today Modern irrigation methods in developing country are needed to fulfill the food demands. Although in these countries Ethiopia, there are many diesel engine operated and rare solar operated water pumps for irrigation; but due to the running cost of diesel and capital cost of photovoltaic irrigation system. So Photovolta...

  16. Memory of irrigation effects on hydroclimate and its modeling challenge

    Science.gov (United States)

    Chen, Fei; Xu, Xiaoyu; Barlage, Michael; Rasmussen, Roy; Shen, Shuanghe; Miao, Shiguang; Zhou, Guangsheng

    2018-06-01

    Irrigation modifies land-surface water and energy budgets, and also influences weather and climate. However, current earth-system models, used for weather prediction and climate projection, are still in their infancy stage to consider irrigation effects. This study used long-term data collected from two contrasting (irrigated and rainfed) nearby maize-soybean rotation fields, to study the effects of irrigation memory on local hydroclimate. For a 12 year average, irrigation decreases summer surface-air temperature by less than 1 °C and increases surface humidity by 0.52 g kg‑1. The irrigation cooling effect is more pronounced and longer lasting for maize than for soybean. Irrigation reduces maximum, minimum, and averaged temperature over maize by more than 0.5 °C for the first six days after irrigation, but its temperature effect over soybean is mixed and negligible two or three days after irrigation. Irrigation increases near-surface humidity over maize by about 1 g kg‑1 up to ten days and increases surface humidity over soybean (~ 0.8 g kg‑1) with a similar memory. These differing effects of irrigation memory on temperature and humidity are associated with respective changes in the surface sensible and latent heat fluxes for maize and soybean. These findings highlight great need and challenges for earth-system models to realistically simulate how irrigation effects vary with crop species and with crop growth stages, and to capture complex interactions between agricultural management and water-system components (crop transpiration, precipitation, river, reservoirs, lakes, groundwater, etc.) at various spatial and temporal scales.

  17. Frequency standards

    CERN Document Server

    Riehle, Fritz

    2006-01-01

    Of all measurement units, frequency is the one that may be determined with the highest degree of accuracy. It equally allows precise measurements of other physical and technical quantities, whenever they can be measured in terms of frequency.This volume covers the central methods and techniques relevant for frequency standards developed in physics, electronics, quantum electronics, and statistics. After a review of the basic principles, the book looks at the realisation of commonly used components. It then continues with the description and characterisation of important frequency standards

  18. Monitoring plant water status and rooting depth for precision irrigation in the vineyards of Classic Karst

    Science.gov (United States)

    Savi, Tadeja; Moretti, Elisa; Dal Borgo, Anna; Petruzzellis, Francesco; Stenni, Barbara; Bertoncin, Paolo; Dreossi, Giuliano; Zini, Luca; Martellos, Stefano; Nardini, Andrea

    2017-04-01

    The extreme summer drought and heat waves that occurred in South-Europe in 2003 and 2012 have led to the loss of more than 50% of winery production in the Classic Karst (NE Italy). The irrigation of vineyards in this area is not appropriately developed and, when used, it does not consider the actual water status and needs of plants, posing risks of inappropriate or useless usage of large water volumes. The predicted future increase in frequency and severity of extreme climate events poses at serious risk the local agriculture based on wine business. We monitored seasonal trends of pre-dawn (Ψpd) and minimum (Ψmin) leaf water potential, and stomatal conductance (gL) of 'Malvasia' grapevine in one mature (MV, both in 2015 and 2016) and one young vineyard (YV, in 2016). Moreover, we extracted xylem sap form plant stems and soil water from samples collected in nearby caves, by cryo-vacuum distillation. We also collected precipitation and irrigation water in different months. Oxygen isotope composition (δ18O) of atmospheric, plant, soil and irrigation water was analyzed to get information about rooting depth. In 2015, at the peak of summer aridity, two irrigation treatments were applied according to traditional management practices. The treatments were performed in a sub-area of the MV, followed by physiological analysis and yield measurements at grape harvest. In 2016, the soil water potential (Ψsoil) at 50 cm depth was also monitored throughout the season. Under harsh environmental conditions the apparently deep root system ensured relatively favorable plant water status in both MV and YV and during both growing seasons. The Ψsoil at 50 cm depth gradually decreased as drought progressed, reaching a minimum value of about -1.7 MPa, far more negative than Ψpd recorded in plants (about -0.5 MPa). In July, significant stomatal closure was observed, but Ψmin never surpassed the critical threshold of -1.3 MPa, indicating that irrigation was not needed. The xylem sap

  19. A Fuzzy analytical hierarchy process approach in irrigation networks maintenance

    Science.gov (United States)

    Riza Permana, Angga; Rintis Hadiani, Rr.; Syafi'i

    2017-11-01

    Ponorogo Regency has 440 Irrigation Area with a total area of 17,950 Ha. Due to the limited budget and lack of maintenance cause decreased function on the irrigation. The aim of this study is to make an appropriate system to determine the indices weighted of the rank prioritization criteria for irrigation network maintenance using a fuzzy-based methodology. The criteria that are used such as the physical condition of irrigation networks, area of service, estimated maintenance cost, and efficiency of irrigation water distribution. 26 experts in the field of water resources in the Dinas Pekerjaan Umum were asked to fill out the questionnaire, and the result will be used as a benchmark to determine the rank of irrigation network maintenance priority. The results demonstrate that the physical condition of irrigation networks criterion (W1) = 0,279 has the greatest impact on the assessment process. The area of service (W2) = 0,270, efficiency of irrigation water distribution (W4) = 0,249, and estimated maintenance cost (W3) = 0,202 criteria rank next in effectiveness, respectively. The proposed methodology deals with uncertainty and vague data using triangular fuzzy numbers, and, moreover, it provides a comprehensive decision-making technique to assess maintenance priority on irrigation network.

  20. Trash-polluted irrigation: characteristics and impact on agriculture

    Science.gov (United States)

    Sulaeman, D.; Arif, SS; Sudarmadji

    2018-04-01

    Trash pollution has been a problem in sustainable water resources management. Trash pollutes not only rivers, lakes and seas, but also irrigation canals and rice fields. This study aimed to identify the characteristics of solid waste (type, time of occurrence and sources of trash) and its impact on agriculture. The study was conducted in four irrigation areas, namely Gamping, Merdiko, Nglaren and Karangploso in Bantul District, Yogyakarta Special Region. We applied the Irrigation Rapid Trash Assessment (IRTA) as our field survey instrument. The results showed that trash was found throughout irrigation canals and rice fields, and the occurrence was influenced by water flow, time and farmer activities. The irrigation was dominantly polluted by plastic trash (52.2%), biodegradable waste (17.91%) and miscellaneous trash (12.3%). The IRTA score showed that Gamping Irrigation Area was at marginal condition, bearing a high risk of disturbing the operation and maintenance of the irrigation canals as well as farmers’ health. Trash in irrigation also generated technical impact of the irrigation operation and maintenance, environmental quality, and social life. This research also offered environmental policy integration approach and water-garbage governance approach as an alternative solution to manage water resources and agriculture in a sustainable manner, under the pressure of increasing amount of trash.

  1. 75 FR 67095 - Rate Adjustments for Indian Irrigation Projects

    Science.gov (United States)

    2010-11-01

    ...; (c) Vehicle and equipment repairs; (d) Equipment costs, including lease fees; (e) Depreciation; (f... Mexico 87104, Telephone: (505) 563-3100. Pine River Irrigation Project..... John Waconda, Superintendent...

  2. 76 FR 58293 - Rate Adjustments for Indian Irrigation Projects

    Science.gov (United States)

    2011-09-20

    ...) Vehicle and equipment repairs; (d) Equipment costs, including lease fees; (e) Depreciation; (f... Mexico 87104, Telephone: (505) 563-3100. Pine River Irrigation Project..... John Waconda, Superintendent...

  3. Uncertainties in modelling the climate impact of irrigation

    Science.gov (United States)

    de Vrese, Philipp; Hagemann, Stefan

    2017-11-01

    Irrigation-based agriculture constitutes an essential factor for food security as well as fresh water resources and has a distinct impact on regional and global climate. Many issues related to irrigation's climate impact are addressed in studies that apply a wide range of models. These involve substantial uncertainties related to differences in the model's structure and its parametrizations on the one hand and the need for simplifying assumptions for the representation of irrigation on the other hand. To address these uncertainties, we used the Max Planck Institute for Meteorology's Earth System model into which a simple irrigation scheme was implemented. In order to estimate possible uncertainties with regard to the model's more general structure, we compared the climate impact of irrigation between three simulations that use different schemes for the land-surface-atmosphere coupling. Here, it can be shown that the choice of coupling scheme does not only affect the magnitude of possible impacts but even their direction. For example, when using a scheme that does not explicitly resolve spatial subgrid scale heterogeneity at the surface, irrigation reduces the atmospheric water content, even in heavily irrigated regions. Contrarily, in simulations that use a coupling scheme that resolves heterogeneity at the surface or even within the lowest layers of the atmosphere, irrigation increases the average atmospheric specific humidity. A second experiment targeted possible uncertainties related to the representation of irrigation characteristics. Here, in four simulations the irrigation effectiveness (controlled by the target soil moisture and the non-vegetated fraction of the grid box that receives irrigation) and the timing of delivery were varied. The second experiment shows that uncertainties related to the modelled irrigation characteristics, especially the irrigation effectiveness, are also substantial. In general the impact of irrigation on the state of the land

  4. Effect of Irrigation CutOff on Flowering Stage and Foliar Application of Spermidine on Some Quantitative and Qualitative Characteristics of Various Ecotypes of Cumin

    Directory of Open Access Journals (Sweden)

    Sarah Bakhtari

    2017-02-01

    Full Text Available Introduction: Medicinal plants play major roles in human health. . Cumin (Cuminum cyminum L. is an annual plant that commonly cultivated in arid and semiarid regions of Iran. The crop has a wide range of uses including medicinal, cosmetic and food industry. Cumin occupies about 26% of the total area devoted to medicinal plants in Iran. However, cumin is seriously affected by the Fusarium wilt and blight diseases. The diseases usually increase under warm and wet conditions. It was demonstrated that the peak of the disease incidence is occurring at the flowering stage and irrigation cutoff at this time may be reduced the diseases density. Materials and methods: In order to evaluate the effects of irrigation cutoff in flowering stage and foliar application of spermidine on some characteristics of various ecotype of cumin, an experiment was conducted in a split-split-plot arrangement in randomized complete block design with three replications at the research farm of Shahid Bahonar University of Kerman at 2014. The experimental treatments were irrigation in two levels (complete irrigation and cutoff the irrigation in flowering stage assigned to main plots, foliar application of spermidine in three levels (0, 1 and 2 Mm as a subplot and cumin ecotypes in three levels (Kerman, Khorasan and Esfahan that was randomized in sub-subplot. Plots size under the trial was 4 m × 3 m so as to get 50 cm inter row spacing in six rows. The ideal density of the crops was considered as 120 plant m-2. As soon as the seeds were sown, irrigation was applied every 10 days. Foliar application of spermidine was done at three stages (after thinning, before flowering stage and in the middle of flowering stage. No herbicides and chemical fertilizers were applied during the expriments. Results and discussion: In this study the number of branches, umbels per plant, 1000-seed weight, seed yield per plant and hectare, harvest index, essential oil percentage and yield, infected

  5. Low Bone Density

    Science.gov (United States)

    ... Density Exam/Testing › Low Bone Density Low Bone Density Low bone density is when your bone density ... people with normal bone density. Detecting Low Bone Density A bone density test will determine whether you ...

  6. Groundwater-fed irrigation impacts spatially distributed temporal scaling behavior of the natural system: a spatio-temporal framework for understanding water management impacts

    International Nuclear Information System (INIS)

    Condon, Laura E; Maxwell, Reed M

    2014-01-01

    Regional scale water management analysis increasingly relies on integrated modeling tools. Much recent work has focused on groundwater–surface water interactions and feedbacks. However, to our knowledge, no study has explicitly considered impacts of management operations on the temporal dynamics of the natural system. Here, we simulate twenty years of hourly moisture dependent, groundwater-fed irrigation using a three-dimensional, fully integrated, hydrologic model (ParFlow-CLM). Results highlight interconnections between irrigation demand, groundwater oscillation frequency and latent heat flux variability not previously demonstrated. Additionally, the three-dimensional model used allows for novel consideration of spatial patterns in temporal dynamics. Latent heat flux and water table depth both display spatial organization in temporal scaling, an important finding given the spatial homogeneity and weak scaling observed in atmospheric forcings. Pumping and irrigation amplify high frequency (sub-annual) variability while attenuating low frequency (inter-annual) variability. Irrigation also intensifies scaling within irrigated areas, essentially increasing temporal memory in both the surface and the subsurface. These findings demonstrate management impacts that extend beyond traditional water balance considerations to the fundamental behavior of the system itself. This is an important step to better understanding groundwater’s role as a buffer for natural variability and the impact that water management has on this capacity. (paper)

  7. Frequency Synthesiser

    NARCIS (Netherlands)

    Drago, Salvatore; Sebastiano, Fabio; Leenaerts, Dominicus M.W.; Breems, Lucien J.; Nauta, Bram

    2016-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  8. Frequency synthesiser

    NARCIS (Netherlands)

    Drago, S.; Sebastiano, Fabio; Leenaerts, Dominicus Martinus Wilhelmus; Breems, Lucien Johannes; Nauta, Bram

    2010-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  9. STUDY ON MICROBIAL COMMUNITIES AND SOIL ORGANIC MATTER IN IRRIGATED AND NON-IRRIGATED VERTISOL FROM BOIANU

    Directory of Open Access Journals (Sweden)

    Sorina Dumitru

    2012-12-01

    Full Text Available Irrigation, when administered correctly, confers the producers the possibility to overcome drought effects and obtain higher yields, supplementing the quality of food for animals or human consumers. In the mean time, soil erosion, pathogens attack and nutrients or pesticides spreading can be prevented by an adequate management of irrigation water. As a consequence, soil microbial community structure, composition and activities, as well as the organic matter quality can be different from those in non-irrigated soil. Research have been carried out in order to assess changes in bacterial and fungal communities and activity in irrigated Vertisol from Boianu, as compared with non-irrigated. The paper presents the results concerning the taxonomical composition of bacterial and fungalmicroflora in the horizons of the two soil profiles, as well as the level of CO2 released by microorganisms. Chromatographic aspects of humus fractions were used to characterize the organic matter in irrigated and nonirrigated soil. Increased moisture and lowered temperature in Ap horizon of irrigated soil increased bacterial counts(18 x106 viable cells x g-1 dry soil and their metabolic activity expressed by carbon dioxide released (46.838mg CO2 x g-1 dry soil comparatively with non- irrigated soil. Fungal microflora was more abundant after 25-50cm under irrigation. Species diversity slightly increased under irrigation in both upper and lower part of soil profile. In irrigated soil, associations of species belonging to bacterial genera Pseudomonas and Bacillus were dominant in surface and white actinomycetes in the depth. Fungal consortia of Penicillium, Aspergillus and Fusarium dominated in both soil profiles.Irrigation induced changes in the quantity and quality of soil organic matter, as well as in the aspect of their migration pattern, as revealed on circular chromatograms.

  10. Irrigation Depletions 1928-1989 : 1990 Level of Irrigation, Snake Yakima and Deschutes River Basins.

    Energy Technology Data Exchange (ETDEWEB)

    United States. Bonneville Power Administation; A.G. Crook Company

    1993-07-01

    The vast amount of irrigation in relation to the available water and extensive system of reservoirs located in the Snake River Basin above Brownlee reservoir precludes this area from using methods such as Blaney-Criddle for estimating irrigation depletions. Also the hydrology, irrigation growth patterns, and water supply problems are unique and complex. Therefore regulation studies were utilized to reflect the net effect on streamflow of the changes in irrigated acreage in terms of corresponding changes in storage regulation and in the amount of water depleted and diverted from and returned to the river system. The regulation study for 1990 conditions was conducted by the Idaho Department of Water Resources. The end product of the basin simulation is 61 years of regulated flows at various points in the river system that are based on 1990 conditions. Data used by the Idaho Department of Water Resources is presented in this section and includes natural gains to the river system and diversions from the river system based on a 1990 level of development and operation criteria. Additional information can be obtained for an Idaho Department of Water Resources Open-File Report ``Stream Flows in the Snake River Basin 1989 Conditions of Use and Management`` dated June 1991. Similar considerations apply to the Yakima and Deschutes river basins.

  11. Irrigating lives : development intervention and dynamics of social relationships in an irrigation project

    NARCIS (Netherlands)

    Magadlela, D.

    2000-01-01

    This study is about rural agricultural development and social processes of change in rural Zimbabwe. It is aimed at understanding how irrigation intervention in a remote rural context changed the cultural, social, political and farming lives of people. It is a study of people coping with

  12. Intervention processes and irrigation institutions : sustainability of farmer managed irrigation systems in Nepal

    NARCIS (Netherlands)

    Pant, D.R.

    2000-01-01

    With the support from various donors, His Majesty's Government of Nepal has implemented support programmes with a view to transform water availability, improve production, and increase the institutional capabilities of farmers to develop and sustain efficient, fair and reliable irrigation

  13. 77 FR 16828 - Turlock Irrigation District, & Modesto Irrigation District; Notice of Dispute Resolution Process...

    Science.gov (United States)

    2012-03-22

    ... 8--Salmon and Steelhead Full Life-Cycle Population Models; and Request 9--Effects of the Project and... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Don Pedro Hydroelectric Project Project... relicensing proceeding for the Don Pedro Hydroelectric Project No. 2299-075.\\1\\ Turlock Irrigation District...

  14. Effect of Different Irrigation and Planting Methods on Water Productivity and Health of Commercial Varieties of Potato

    Directory of Open Access Journals (Sweden)

    H. R Salemi

    2016-07-01

    Full Text Available Introduction Water crisis as a main factor of agronomy limitation exists in all over the arid and semiarid regions such as Isfahan, province which is located in the central part of the Zayandehrud River Basin (ZRB. Due to the increase in the cultivated area of potato in Fareidan Region located in the west of Isfahan province, it will be necessary to use pressurized irrigation systems to achieve the highest irrigation application efficiency and water productivity. Materials and Methods The ZRB (41,500 km2 is a closed basin with no outlet to the sea. The research was conducted in the Fareidan region of Isfahan, which is located in the west part of the ZRB. The Rozveh Agricultural Research Station (32°, 58' N, 50°, 25' E is located at the altitude of 2390 m above the sea level. This study was conducted as a randomized complete blocks design as a split strip plot layout with three replications and during two years (2007-2008. Three irrigation systems (Drip tape, Sprinkler and furrow were considered as main plots, two planting methods (one - row planting and two-row planting as split subplots and two potato cultivars (Marfuna and Agria as split-split subplots. Production (Tuber-yield, the consumption water and cultivars reactions to common diseases were evaluated in different treatments. The soil of the experimental area, according to USDA Soil Taxonomy 1994 is of silty loamy. At the soil depth of 1m, soil salinity (1.1-2.0 dS m-1, water salinity (1.24 dS m-1, soil moisture at field capacity (23 Vol. %, and bulk density (BD = 1.44 g/cm3 at the field site were measured or experimentally obtained in the Isfahan Soil and Water Laboratory. The results were subjected to an ANOVA to analyze the effects of the treatments and their interactions. The data obtained were analyzed using the compound variance analysis and the averages of different treatments were separated using the Duncan multiple range test using the statistical software (SAS Institute, Inc

  15. Outdoor Irrigation Measurement and Verification Protocol

    Energy Technology Data Exchange (ETDEWEB)

    Kurnik, Charles W. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Stoughton, Kate M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Figueroa, Jorge [Western Resource Advocates, Boulder, CO (United States)

    2017-12-05

    This measurement and verification (M&V) protocol provides procedures for energy service companies (ESCOs) and water efficiency service companies (WESCOs) to determine water savings resulting from water conservation measures (WCMs) in energy performance contracts associated with outdoor irrigation efficiency projects. The water savings are determined by comparing the baseline water use to the water use after the WCM has been implemented. This protocol outlines the basic structure of the M&V plan, and details the procedures to use to determine water savings.

  16. Irrigation of treated wastewater in Braunschweig, Germany

    DEFF Research Database (Denmark)

    Ternes, T.A.; Bonerz, M.; Herrmann, N.

    2007-01-01

    pharmaceuticals and two personal care products (PPCPs; e.g. betablockers, antibiotics, antiphlogistics, carbamazepine, musk fragrances, iodinated contrast media (ICM) and estrogens). No differences in PPCP pollution of the groundwater were found due to irrigation of STP effluents with and without addition....... In the groundwater and lysimeter samples primarily the ICM diatrizoate and iopamidol, the antiepileptic carbamazepine and the antibiotic sulfamethoxazole were detected up to several mu g l(-1), while the acidic pharmaceuticals, musk fragrances, estrogens and betablockers were likely sorbed or transformed while...

  17. Assessing the changes of groundwater recharge / irrigation water use between SRI and traditional irrigation schemes in Central Taiwan

    Science.gov (United States)

    Chen, Shih-Kai; Jang, Cheng-Shin; Tsai, Cheng-Bin

    2015-04-01

    To respond to agricultural water shortage impacted by climate change without affecting rice yield in the future, the application of water-saving irrigation, such as SRI methodology, is considered to be adopted in rice-cultivation in Taiwan. However, the flooded paddy fields could be considered as an important source of groundwater recharge in Central Taiwan. The water-saving benefit of this new methodology and its impact on the reducing of groundwater recharge should be integrally assessed in this area. The objective of this study was to evaluate the changes of groundwater recharge/ irrigation water use between the SRI and traditional irrigation schemes (continuous irrigation, rotational irrigation). An experimental paddy field located in the proximal area of the Choushui River alluvial fan (the largest groundwater pumping region in Taiwan) was chosen as the study area. The 3-D finite element groundwater model (FEMWATER) with the variable boundary condition analog functions, was applied in simulating groundwater recharge process and amount under traditional irrigation schemes and SRI methodology. The use of effective rainfall was taken into account or not in different simulation scenarios for each irrigation scheme. The simulation results showed that there were no significant variations of infiltration rate in the use of effective rainfall or not, but the low soil moisture setting in deep soil layers resulted in higher infiltration rate. Taking the use of effective rainfall into account, the average infiltration rate for continuous irrigation, rotational irrigation, and SRI methodology in the first crop season of 2013 were 4.04 mm/day, 4.00 mm/day and 3.92 mm/day, respectively. The groundwater recharge amount of SRI methodology was slightly lower than those of traditional irrigation schemes, reducing 4% and 2% compared with continuous irrigation and rotational irrigation, respectively. The field irrigation requirement amount of SRI methodology was significantly

  18. Distillation irrigation: a low-energy process for coupling water purification and drip irrigation

    Science.gov (United States)

    Constantz, J.

    1989-01-01

    A method is proposed for combining solar distillation and drip irrigation to simultaneously desalinize water and apply this water to row crops. In this paper, the basic method is illustrated by a simple device constructed primarily of sheets of plastic, which uses solar energy to distill impaired water and apply the distillate to a widely spaced row crop. To predict the performance of the proposed device, an empirical equation for distillate production, dp, is developed from reported solar still production rates, and a modified Jensen-Haise equation is used to calculate the potential evapotranspiration, et, for a row crop. Monthly values for et and dp are calculated by using a generalized row crop at five locations in the Western United States. Calculated et values range from 1 to 22 cm month-1 and calculated dp values range from 2 to 11 cm month-1, depending on the location, the month, and the crop average. When the sum of dp plus precipitation, dp + P, is compared to et for the case of 50% distillation irrigation system coverage, the results indicate that the crop's et is matched by dp + P, at the cooler locations only. However, when the system coverage is increased to 66%, the crop's et is matched by dp + P even at the hottest location. Potential advantages of distillation irrigation include the ability: (a) to convert impaired water resources to water containing no salts or sediments; and (b) to efficiently and automatically irrigate crops at a rate that is controlled primarily by radiation intensities. The anticipated disadvantages of distillation irrigation include: (a) the high costs of a system, due to the large amounts of sheeting required, the short lifetime of the sheeting, and the physically cumbersome nature of a system; (b) the need for a widely spaced crop to reduce shading of the system by the crop; and (c) the production of a concentrated brine or precipitate, requiring proper off-site disposal. ?? 1989.

  19. Climate change and irrigation. An Australian response

    International Nuclear Information System (INIS)

    Pigram, J.J.

    1995-01-01

    Climatic changes on a global or regional scale, resulting from human activities, and the likely effects of such changes on Australia were discussed. Irrigation concerns of the Murray-Darling Basin in southeast Australia associated with global climate were described. Potential risks for regional economies and communities (agriculture in this instance) which may be significant, were assessed. Restructuring of the irrigation industry, and appropriate policy initiatives were urged now, while there is still some time to prepare. Application of the 'Precautionary Principle' to reduce global climate change effects was recommended. (This principle states that in areas threatened by severe climatic change lack of full scientific certainty should not be used as an excuse to delay decisive measures designed to mitigate environmental degradation). Bold policy adjustments and the creation of a new institutional framework to promote sustainable resource management were called for. It was suggested that the region could become a 'laboratory' for the whole world for assessing the effectiveness of managerial responses to environmental changes

  20. PRODUCTION OF TOMATO SEEDLINGS UNDER SALINE IRRIGATION

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Brasiliano Campos

    2007-01-01

    Full Text Available Processing tomato is the most important vegetable crop of the Brazilian agribusiness and few researches have been conducted to evaluate the tolerance of this crop to saline stress. In this study, the effects of five levels of salinity of the irrigation water (1, 2, 3, 4 and 5 dS m-1 and three equivalent proportions of Na:Ca:Mg (1:1:0.5, 4:1:0.5 and 7:1:0.5 were tested on the emergence and vigor of processing tomato, cultivar IPA 6. Seeds were sowed in expanded polystyrene tray (128 cells and each tray received 1 L of water after sowing. The trays were piled and, four days after sowing, they were placed on suspended supports in a greenhouse. Irrigation was accomplished daily from the fifth day after sowing. Only dry weight of shoot and root was affected by sodium proportions, while linear reductions of the speed of emergence, stem length and the dry weight of shoot and root were observed with increasing salinity. Root was more affected than shoot by salinity and relative growth ratioincreased with salinity levels on the 14-21 days after sowing period, indicating that the crop showed a certain increase of salinity tolerance with the time of exposure to salts.

  1. Activation of Alkaline Irrigation Fluids in Endodontics

    Directory of Open Access Journals (Sweden)

    Laurence J. Walsh

    2017-10-01

    Full Text Available In conventional endodontic treatment, alkaline solutions of sodium hypochlorite (NaOCl and ethylenediaminetetraacetic acid (EDTA are used in combination to disinfect the root canal system and to eliminate debris and smear layers. An important concept that has emerged over recent years is the use of active physical methods for agitating these fluids to improve their penetration within areas that are not reached by endodontic instruments and to accelerate the chemical actions of these alkaline fluids against planktonic microorganisms, biofilms, soft tissue remnants and smear layers. Ultrasonic agitation and more recently pulsed lasers have emerged as two promising methods for activating endodontic irrigation fluids. Ultrasonic agitation with piezoelectric devices employs a moving tip, while laser agitation uses a stationary tip. Both methods cause cavitation, followed by implosions and shear forces which assist with debridement. Fluid streaming further enhances the activity of the fluids. While agitation enhances performance of irrigants, extrusion of fluids from the root canal during activation is a hazard that must be controlled.

  2. Estimates of Savings Achievable from Irrigation Controller

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Alison; Fuchs, Heidi; Whitehead, Camilla Dunham

    2014-03-28

    This paper performs a literature review and meta-analysis of water savings from several types of advanced irrigation controllers: rain sensors (RS), weather-based irrigation controllers (WBIC), and soil moisture sensors (SMS).The purpose of this work is to derive average water savings per controller type, based to the extent possible on all available data. After a preliminary data scrubbing, we utilized a series of analytical filters to develop our best estimate of average savings. We applied filters to remove data that might bias the sample such as data self-reported by manufacturers, data resulting from studies focusing on high-water users, or data presented in a non-comparable format such as based on total household water use instead of outdoor water use. Because the resulting number of studies was too small to be statistically significant when broken down by controller type, this paper represents a survey and synthesis of available data rather than a definitive statement regarding whether the estimated water savings are representative.

  3. Level densities

    International Nuclear Information System (INIS)

    Ignatyuk, A.V.

    1998-01-01

    For any applications of the statistical theory of nuclear reactions it is very important to obtain the parameters of the level density description from the reliable experimental data. The cumulative numbers of low-lying levels and the average spacings between neutron resonances are usually used as such data. The level density parameters fitted to such data are compiled in the RIPL Starter File for the tree models most frequently used in practical calculations: i) For the Gilber-Cameron model the parameters of the Beijing group, based on a rather recent compilations of the neutron resonance and low-lying level densities and included into the beijing-gc.dat file, are chosen as recommended. As alternative versions the parameters provided by other groups are given into the files: jaeri-gc.dat, bombay-gc.dat, obninsk-gc.dat. Additionally the iljinov-gc.dat, and mengoni-gc.dat files include sets of the level density parameters that take into account the damping of shell effects at high energies. ii) For the backed-shifted Fermi gas model the beijing-bs.dat file is selected as the recommended one. Alternative parameters of the Obninsk group are given in the obninsk-bs.dat file and those of Bombay in bombay-bs.dat. iii) For the generalized superfluid model the Obninsk group parameters included into the obninsk-bcs.dat file are chosen as recommended ones and the beijing-bcs.dat file is included as an alternative set of parameters. iv) For the microscopic approach to the level densities the files are: obninsk-micro.for -FORTRAN 77 source for the microscopical statistical level density code developed in Obninsk by Ignatyuk and coworkers, moller-levels.gz - Moeller single-particle level and ground state deformation data base, moller-levels.for -retrieval code for Moeller single-particle level scheme. (author)

  4. Remote sensing technologies applied to the irrigation water management on a golf course

    Science.gov (United States)

    Pedras, Celestina; Lança, Rui; Martins, Fernando; Soares, Cristina; Guerrero, Carlos; Paixão, Helena

    2015-04-01

    An adequate irrigation water management in a golf course is a complex task that depends upon climate (multiple microclimates) and land cover (where crops differ in morphology, physiology, plant density, sensitivity to water stress, etc.). These factors change both in time and space on a landscape. A direct measurement provides localized values of the evapotranspiration and climate conditions. Therefore this is not a practical or economical methodology for large-scale use due to spatial and temporal variability of vegetation, soils, and irrigation management strategies. Remote sensing technology combines large scale with ground measurement of vegetation indexes. These indexes are mathematical combinations of different spectral bands mostly in the visible and near infrared regions of the electromagnetic spectrum. They represent the measures of vegetation activity that vary not only with the seasonal variability of green foliage, but also across space, thus they are suitable for detecting spatial landscape variability. The spectral vegetation indexes may enhance irrigation management through the information contained in spectral reflectance data. This study was carried out on the 18th fairway of the Royal Golf Course, Vale do Lobo, Portugal, and it aims to establish the relationship between direct measurements and vegetation indexes. For that it is required (1) to characterize the soil and climatic conditions, (2) to assessment of the irrigation system, (3) to estimate the evapotranspiration (4) and to calculate the vegetation indices. The vegetation indices were determined with basis on spectral bands red, green and blue, RGB, and near Infrared, NIR, obtained from the analysis of images acquired from a unpiloted aerial vehicle, UAV, platform. The measurements of reference evapotranspiration (ETo) were obtained from two meteorological stations located in the study area. The landscape evapotranspiration, ETL, was determined in the fairway with multiple microclimates

  5. [Optimal irrigation index for cotton drip irrigation under film mulching based on the evaporation from pan with constant water level].

    Science.gov (United States)

    Shen, Xiao-Jun; Zhang, Ji-Yang; Sun, Jing-Sheng; Gao, Yang; Li, Ming-Si; Liu, Hao; Yang, Gui-Sen

    2013-11-01

    A field experiment with two irrigation cycles and two irrigating water quotas at squaring stage and blossoming-boll forming stage was conducted in Urumqi of Xinjiang Autonomous Region, Northwest China in 2008-2009, aimed to explore the high-efficient irrigation index of cotton drip irrigation under film mulching. The effects of different water treatments on the seed yield, water consumption, and water use efficiency (WUE) of cotton were analyzed. In all treatments, there was a high correlation between the cotton water use and the evaporation from pan installed above the plant canopy. In high-yield cotton field (including the treatment T4 which had 10 days and 7 days of irrigation cycle with 30.0 mm and 37.5 mm of irrigating water quota at squaring stage and blossoming-boll forming stage, respectively in 2008, and the treatment T1 having 7 days of irrigation cycle with 22.5 mm and 37.5 mm of irrigating water quota at squaring stage and blossoming-boll forming stage, respectively in 2009), the pan-crop coefficient (Kp) at seedling stage, squaring stage, blossoming-boll forming stage, and boll opening stage was 0.29-0.30, 0.52-0.53, 0.74-0.88, and 0.19-0.20, respectively. As compared with the other treatments, T4 had the highest seed cotton yield (5060 kg x hm(-2)) and the highest WUE (1.00 kg x m(-3)) in 2008, whereas T1 had the highest seed cotton yield (4467 kg x hm(-2)) and the highest WUE (0.99 kg x m(-3)) in 2009. The averaged cumulative pan evaporation in 7 days and 10 days at squaring stage was 40-50 mm and 60-70 mm, respectively, and that in 7 days at blossoming-boll forming stage was 40-50 mm. It was suggested that in Xinjiang cotton area, irrigating 45 mm water for seedling emergence, no irrigation both at seedling stage and at boll opening stage, and irrigation was started when the pan evaporation reached 45-65 mm and 45 mm at squaring stage and blossoming-boll stage, respectively, the irrigating water quota could be determined by multiplying cumulative

  6. Biological soil attributes in oilseed crops irrigated with oilfield produced water in the semi-arid region

    Directory of Open Access Journals (Sweden)

    Ana Clarice Melo Azevedo de Meneses

    Full Text Available ABSTRACT Wastewater from oil is the main residue of the oil industry. Studies have shown that wastewater, or produced water, can be treated and used as an alternative source for the irrigation of oilseed crops. The aim of this work was to evaluate the effect of treated produced water on the biological properties of soil cultivated with the castor bean cv. BRS Energy and the sunflower cv. BRS 321 respectively, for two and three successive cycles of grain production. The first cycle in the sunflower and castor bean corresponds to the dry season and the second cycle to the rainy season. The third crop cycle in the sunflower relates to the dry season. The research was carried out from August 2012 to October 2013, in the town of Aracati, in the State of Ceará (Brazil, where both crops were submitted to irrigation with filtered produced water (FPW, produced water treated by reverse osmosis (OPW, or groundwater water from the Açu aquifer (ACW, and to no irrigation (RFD. The treatments, with three replications, were evaluated during the periods of pre-cultivation and plant reproduction for soil respiration (Rs, total organic carbon (TOC and the population density of bacteria (Bact and filamentous fungi (Fung in the soil. In the sunflower crop, these soil attributes are sensitive to the irrigation water used. Irrigation of the castor bean affects soil respiration. Under the conditions of this study, irrigation with FPW may be a short-term alternative in the castor bean and sunflower crops.

  7. Investigating deficit irrigation as a climate-smart farming option

    Science.gov (United States)

    Global water supplies available for irrigation are declining while food demand continues to rise. Deficit irrigation offers a promising strategy to reduce water use with minimal impacts to yields, but is likely to have a range of impacts on soil nutrient cycling processes and climate change mitigati...

  8. Yield response and economics of shallow subsurface drip irrigation systems

    Science.gov (United States)

    Field tests were conducted using shallow subsurface drip irrigation (S3DI) on cotton (Gossypium hirsutum, L.), corn (Zea mays, L.), and peanut (Arachis hypogeae, L.) in rotation to investigate yield potential and economic sustainability of this irrigation system technique over a six year period. Dri...

  9. Agriculture and wildlife: ecological implications of subsurface irrigation drainage

    Science.gov (United States)

    A. Dennis Lemly

    1994-01-01

    Subsurface agricultural irrigation drainage is a wastewater with the potential to severely impact wetlands and wildlife populations. Widespread poisoning of migratory birds by drainwater contaminants has occurred in the western United States and waterfowl populations are threatened in the Pacific and Central flyways. Irrigated agriculture could produce subsurface...

  10. Atmospheric effects of irrigation in monsoon climate: the Indian subcontinent

    NARCIS (Netherlands)

    Tuinenburg, O.A.

    2013-01-01

    During the 20th century, an increasing population increased the demand for food. As a consequence, agricultural activity has expanded and become more intense. A part of this intensification is the use of irrigation systems to water crops. Due to this irrigation, dams and channeling systems,

  11. Salinity guidelines for irrigation: Case studies from Water Research ...

    African Journals Online (AJOL)

    the entire fruit and wine industries are dependent on irrigation. Cropping in the Eastern and Northern Cape also relies heavily on irrigation. ..... The soils were described as deep, fine sandy, dominantly red, ..... crops. For example, leaves of deciduous fruit trees (apri- ..... Laboratory Handbook 60, USDA, Washington. 160 pp.

  12. Performance evaluation of sprinkler irrigation system at Mambilla ...

    African Journals Online (AJOL)

    Variation in discharge can also be adjusted via use of uniform laterals, risers, and nozzles. This study further recommends an incorporation of a soil and water laboratory for the company to aid in monitoring the soil and water quality of the irrigation area. Keywords: Tea, irrigation System, Performance Evaluation ...

  13. Effects of different irrigation regimes on vegetative growth, fruit yield ...

    African Journals Online (AJOL)

    This study was conducted during five growing seasons from 2004 to 2008 to investigate effects of different irrigation regimes on vegetative growth, fruit yield and quality of Salak apricot trees in semiarid climatic conditions. There were six irrigation treatments, five of which (S1, S2, S3, S4 and S5) were based on adjustment ...

  14. Effects of different irrigation programs on yield and quality ...

    African Journals Online (AJOL)

    Evapotranspiration (ET) values varied from 93.1 to 466.3 mm for the treatments. The highest yield was obtained from the S3 and S4 treatments. A significant polynomial correlation was obtained between the yield and irrigation water, and between the yield and ET (P < 0.01). This indicated that when irrigation water and ET ...

  15. Thermal infrared sensors for postharvest deficit irrigation of peach

    Science.gov (United States)

    California has been in a historic drought and the lack of water has been a major problem for agriculture especially for crops that depend on irrigation. A multi-year field study was carried out to demonstrate the feasibility of applying thermal infrared sensors for managing deficit irrigation in an ...

  16. Wireless sensor network effectively controls center pivot irrigation of sorghum

    Science.gov (United States)

    Robust automatic irrigation scheduling has been demonstrated using wired sensors and sensor network systems with subsurface drip and moving irrigation systems. However, there are limited studies that report on crop yield and water use efficiency resulting from the use of wireless networks to automat...

  17. Small private irrigation: Enhancing benefits and managing trade-offs

    NARCIS (Netherlands)

    Giordano, M.; Fraiture, de C.M.S.

    2014-01-01

    Millions of smallholder farmers in sub-Saharan Africa and South Asia benefit from readily available and affordable irrigation technologies. The rapid uptake of small private irrigation in South Asia had a proven positive effect on poverty alleviation. In sub-Saharan Africa similar trends are

  18. [Ecological risks of reclaimed water irrigation: a review].

    Science.gov (United States)

    Chen, Wei-Ping; Zhang, Wei-Ling; Pan, Neng; Jiao, Wen-Tao

    2012-12-01

    Wastewater reclamation and reuse have become an important approach to alleviate the water crisis in China because of its social, economic and ecological benefits. The irrigation on urban green space and farmland is the primary utilization of reclaimed water, which has been practiced world widely. To understand the risk of reclaimed water irrigation, we summarized and reviewed the publications associated with typical pollutants in reclaimed water including salts, nitrogen, heavy metals, emerging pollutants and pathogens, systematically analyzed the ecological risk posed by reclaimed water irrigation regarding plant growth, groundwater quality and public health. Studies showed that salt and salt ions were the major risk sources of reclaimed water irrigation, spreading disease was another potential risk of using reclaimed water, and emerging pollutants was the hot topic in researches of ecological risk. Based on overseas experiences, risk control measures on reclaimed water irrigation in urban green space and farmland were proposed. Five recommendations were given to promote the safe use of reclaimed water irrigation including (1) strengthen long-term in situ monitoring, (2) promote the modeling studies, (3) build up the connections of reclaimed water quality, irrigation management and ecological risk, (4) evaluate the soil bearing capacity of reclaimed water irrigation, (5) and establish risk management system of reclaimed water reuse.

  19. Root Zone Sensors for Irrigation Management in Intensive Agriculture

    NARCIS (Netherlands)

    Pardossi, A.; Incrocci, L.; Incrocci, G.; Marlorgio, F.; Battista, P.; Bacci, L.; Rapi, B.; Marzialetti, P.; Hemming, J.; Balendonck, J.

    2009-01-01

    Crop irrigation uses more than 70% of the world’s water, and thus, improving irrigation efficiency is decisive to sustain the food demand from a fast-growing world population. This objective may be accomplished by cultivating more water-efficient crop species and/or through the application of

  20. land evaluation for improved rice production in watari irrigation

    African Journals Online (AJOL)

    DR. AMINU

    This study aimed at raising irrigated rice production in Watari Irrigation scheme, in Kano state, as to bridge the gap ... land including details about maintenance and ... Area of Kano state and cover a total of 4,574 .... which requires a depth of more than 50cm for efficient .... raise the productivity of the soils to optimum for.