565 research outputs found

    Effect of different defoliants and application times on the yield and quality components of cotton in semi-arid conditions

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    This study was conducted to determine the effect of different defoliants (Dropp ultra® (DU): thidiazuron+diuron and Roundup (RU): glyphosate) and application times [60, 75 and 90 days after flowering (DAF)] on cotton. The research was carried out at the Harran University, Faculty of Agriculture Research and Application Center in 2001 and 2002 using cotton variety cv. Stoneville-453. Experiments were arranged as split plot design with three replications. Defoliations were at the main plots and application times at the subplots. Experimental plots were consisted of six rows, 10 m in length, interrow was 0.70 m and intra-row spacing was 0.20 m. The results of the study indicated that the application of DU defoliant at 60 days after flowering reduced seed cotton yield, number of bolls, boll weight and lint index. With this, seed cotton yield, number of bolls, boll weight and lint index increased with delayed defoliation time in both years. Also, there were no statistically significant differences between the treatments in terms of ginning outturn, fiber length, fiber strength and fiber fineness. It was also found that the application of 2000 cc ha-1 RU was not enough as a dose to affect leaf defoliation and other investigated components

    Investigating the roughness effect of biofouling on propeller performance

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    As a result of the increasing pressure being placed on the marine industry to address ship emissions, regulations to govern the fuel efficiency and efficient operation of ships in the form of the Energy Efficiency Design Index (EEDI) (IMO, 2014) and Energy Efficiency Operation Index (EEOI) (IMO, 2009a) have recently come into force. These have been introduced alongside regulations concerning specific emissions requirements (UNFCCC). Attention has therefore been turned to all aspects of ship design and operation which have impact on their efficiency. In turn, this paper focuses on the effects of biofouling on propeller surfaces highlighting the benefits of reducing biofouling. This subject was the focus of a recently completed EU-Funded FP7 Project entitled FOUL-X-SPEL (2011). This paper investigates the detrimental impacts of biofouling on the performance of a real ship propeller using Computational Fluid Dynamics (CFD) simulations. Initially, the CFD approach used in this study was validated through CFD open-water tests of a propeller. A previously-developed CFD approach for approximating the surface roughness that results from biofouling has then been applied in order to predict the effects on propeller efficiency. The roughness effects of a typical coating and different fouling conditions on the propeller performance were therefore predicted for various advance coefficients Results indicated negative effects of biofouling on the propeller efficiency and the importance of the mitigation of such effects, supporting the importance of informing the industry about the impacts such that they are able to make informed decisions regarding regular propeller maintenance and cleanin

    Volumetric and three-dimensional examination of sella turcica by cone-beam computed tomography: reference data for guidance to pathologic pituitary morphology

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    Background: The aim of the study was to assess the dimensions and volume of sella turcica in healthy Caucasian adults with normal occlusion and facial appearance from cone-beam computed tomography (CBCT) images. Materials and methods: CBCT images of 80 Caucasian adult patients (40 males, 40 females) with normal facial appearance and occlusion taken previously for diagnostic purposes were evaluated. Two groups were constructed in accordance to gender. The volume, length, diameter, and depth of the sella turcica were measured by Romexis software programme. Mann-Whitney U test and Independent t-tests were used for statistical analysis. Results: The mean lengths of the sella were 9.9 mm and 10.2 mm, depths were 9.2 mm and 8.8 mm and diameters were 12.3 mm and 12.1 mm in female and male groups, respectively. Between the genders, no statistically significant differences were found for any of the measurements. There were significantly higher values for the volume of sella turcica in males than in females (1102 ± 285.3 mm3 and 951.3 ± 278.5 mm3, respectively). Conclusions: The dimensions of sella turcica in healthy Caucasian adults with normal occlusion and facial appearance revealed nonsignificant differences between the genders. Individual variability in dimensions and gender differences in the volume are of importance in comparison of patients with craniofacial syndromes and aberrations. Knowledge concerning the dimensions and volume of sella turcica will be clinically relevant for a guidance to consciously realize pituitary disorders

    Asymptotic behaviour of dam break flow for small times

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    Two dimensional impulsive flow of a fluid is studied within the potential flow theory. Initially the fluid is at rest and is held on one side of a vertical plate. The plate is withdrawn suddenly and gravity driven flow of the fluid starts. Attention is paid to the singular behaviour of the velocity field at the bottom point, where the vertical free surface meets the rigid bottom. The linear problem is solved by the Fourier series method. An inner region solution is found using Mellin transform at the bottom point. The jet formation is observed at the bottom point. Also the discontinuity at the upper corner point is dealt with Lagrangian variables. For the second order outer problem, domain decomposition method is used. Comparison of the shapes of the free surfaces near the upper corner point with leading and second order solutions shows that the second order outer solution outer makes a larger difference in the vertical free surface than in the horizontal portion, compared with leading order solution.The complete picture of the shapes of the free surfaces using Lagrangian description for the upper part and Eulerian description for the bottom part at the second order is obtained

    Diurnal gradual heat stress affects antioxidant enzymes, proline accumulation and some physiological components in cotton (Gossypium hirsutum L.)

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    Even though high temperatures significantly reduce both vegetative growth and yield in cotton, very little is known about the effects of heat stress on cotton antioxidant system. Thus, the effects of gradual heat stress on cotton growth in controlled conditions were investigated in the present study. At squaring stage, cotton plants were subjected to two different temperatures, 38 and 45°C to determine the influence of heat stress on the plants. The results of the present study showed that heat stress did not significantly altered the levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in the leaves, whereas there was a remarkable decline in proline quantity of the leaves of plants subjected to 45°C heat stress. As for the amount of total chlorophyll content, a slight increase at plants treated with 38°C temperature was observed. Furthermore, the activities of some enzymes such as superoxide dismutase (SOD), which were associated with heat stress response in other plants was also investigated. For example, there was decline in the activitity of SOD in the plants exposed to high temperatures. On the contrary, catalase (CAT) activity increased at 45°C; peroxidase (POX) activity increased at 38°C and ascorbate peroxidase (APX) activity increased at 38 and 45°C. The results from this study suggest a potential role for CAT, POX and APX in the reduction of elevated levels of H2O2 in cotton plants grown under heat stress condition. To sum up, it could be concluded that, diurnal gradual heat stress caused a low oxidative injury in cotton

    Excess Heat Capacity Surfaces for Water-Alkanol Mixtures by the UNIQUAC Model

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    Pregnancy and Crimean-Congo haemorrhagic fever

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    AbstractCrimean-Congo Hemorrhagic fever (CCHF) is a potentially fatal viral infection with reported case fatality rates of 5–30%. Humans become infected through tick bites, by contact with a patient with CCHF during the acute phase of infection, or by contact with blood or tissues from viraemic livestock. In this first report in the literature, we present the characteristics of three pregnant women with CCHF infection and the outcome of their babies. Transmission of the CCHF infection could be either intrauterine or perinatal. In endemic regions, CCHF infection should be considered in the differential diagnosis of HELLP syndrome (haemolytic anaemia, elevated liver enzymes, low platelet count), and obstetricians should be familiar with the characteristics of CCHF infection. In the aetiology of necrotising enterocolitis, CCHF should be considered

    Experimental determination of the roughness functions of marine coatings

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    The aim of this paper is to determine the roughness functions of different marine coatings, including two novel FOUL-X-SPEL paints and two existing commercial coatings, and two control surfaces, using the overall method of Granville (1987). An extensive series of towing tests of flat plates coated with different antifouling coatings was carried out at the Kelvin Hydrodynamics Laboratory (KHL) of the University of Strathclyde. The tests were designed to examine the as applied drag performances of FOUL-X-SPEL paints and compare them with two existing reference paints and two control surfaces. The surface roughness amplitude parameters of all of the test surfaces were measured using a hull roughness analyser. In total over 150 runs were carried out, including a series of repeat tests designed to quantify the uncertainty in the results. The drag coefficients and roughness function values of each surface were evaluated along with the uncertainty limits

    Life cycle assessment of marine coatings applied to ship hulls

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    This paper presents the methodology developed for Life Cycle Assessment (LCA) of antifouling marine coatings with regards to fouling accumulation on hulls and maintenance of ships. The methodology is based on mathematical models vis-à-vis the environmental and monetary impacts involved in the production and application of hull coatings, added fuel consumption due to fouling accumulation on ship hulls, and hull maintenance. This subject was investigated in a recently completed EU-Funded FP7 Project entitled FOUL-X-SPEL. The LCA methodology was developed using the results of the studies conducted by FOUL-X-SPEL Consortium as well as additional data provided by coating manufacturers, shipyards and shipping companies. Following the introduction of the new LCA model, a case study was carried out to show how to utilize the model using a real tanker which is assumed to be coated with 2 different types of existing coatings, namely a silicone-based fouling release coating and a tin free self-polishing antifouling paint. The total costs and emissions due to the use of different coating types were calculated for the whole life-cycle of the ship. It has been found that CO2 emission reduction due to mitigation of fouling can be achieved using a silicone-based fouling release coating while reducing the cost by means of fuel cost reductions for the shipowners despite the additional capital expenses. The developed LCA model can help stake-holders determine the most feasible paint selection as well as the optimal hull-propeller maintenance schedules and make condition based maintenance decisions

    Yield conditions for deformation of amorphous polymer glasses

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    Shear yielding of glassy polymers is usually described in terms of the pressure-dependent Tresca or von Mises yield criteria. We test these criteria against molecular dynamics simulations of deformation in amorphous polymer glasses under triaxial loading conditions that are difficult to realize in experiments. Difficulties and ambiguities in extending several standard definitions of the yield point to triaxial loads are described. Two definitions, the maximum and offset octahedral stresses, are then used to evaluate the yield stress for a wide range of model parameters. In all cases, the onset of shear is consistent with the pressure-modified von Mises criterion, and the pressure coefficient is nearly independent of many parameters. Under triaxial tensile loading, the mode of failure changes to cavitation.Comment: 9 pages, 8 figures, revte
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