Intensive Leakage Research Articles

Estimation of N2O Emissions from Agricultural Soils and Determination of Nitrogen Leakage

Leaching of nitrogen from the soil is a natural but unfavorable effect that generates N2O emissions. Exact quantification of nitrogen leakage is a challenging process. Intensive leakage occurs mainly when the soil is without vegetation and under specific climatic conditions. This paper aims to quantify the amount of nitrogen leakage from arable land and grassland, and to estimate N2O emissions in 2017. Estimating the country-specific fraction of leached nitrogen (FracLEACH) is important for the emission balance from this source. Emissions are underestimated when the fraction is low; on the contrary, a high fraction causes overestimation. The internationally recognized fraction is 30%, according to the 2006 Intergovernmental Panel on Climate Control (IPCC) Guidelines. This factor represents the fraction of nitrogen losses compared to total nitrogen inputs and sources. In this study, we analyzed the effects of climatic conditions on agricultural soils in Slovakia to evaluate the area of nitrogen loss through leaching.

Experimental Research and CFD Calculations Based Investigations Into Gas Flow in a Short Segment of a Heavily Worn Straight Through Labyrinth Seal

Abstract Steam turbines are used as propulsion components in not only power plants but also on merchant and naval ships. The geometry of the steam turbine seals changes throughout the machine life cycle. The rate of deterioration of these seals, in turn, affects heavily the efficiency of the thermal machine. However, the literature overview does not provide any research reports on flow phenomena occurring in heavily deteriorated seals. The paper describes the course and results of investigations into a model straight through labyrinth seal composed of 4 discs, each with the slot height of 2 mm. The investigations have been conducted with air as the working medium. Changes of gas flow parameters due to wear were analysed. Based on the experimental data, more intensive leakage was observed as the result of the increased slot height. The static pressure distribution along the examined segment was measured. The experimentally recorded distribution differed remarkably from the theoretical assumptions. Another part of the experimental research focused on comparing the gas velocities at points situated upstream of the first and second seal disc. The velocity measurements were carried out using a constant temperature wire probe. This part of the investigations provided opportunities for analysing the influence of seal wear on gas flow conditions in the seal segment. The paper compares the results of the experimental research with those obtained using the CFX software. The presented results of velocity distributions provide a clear picture of the nature of the gas flow in the seal, which enables its analysis.

Experimental study and kinetic analysis on sodium oxide–silica reaction

ABSTRACTIn a sodium-cooled fast reactor (SFR), if considering hypothetical severe accidental condition such as the steel liner failure of structural concrete caused by intensive leakage of liquid sodium (Na) coolant, the liquid sodium–concrete reaction (SCR) may take place. The major consequences of SCR are hydrogen release, energy release and concrete ablation. Thus, it is important to understand the phenomenology and kinetic behavior of SCR. As a part of a series of studies on SCR, this study focused on the reaction between sodium oxide (Na2O) and silica (SiO2), which is dealt with possible formation of Na2O as the result of sodium–water reaction in the initial stage of SCR. Through thermoanalytical and X-ray diffraction measurements, it was revealed that Na2O–SiO2 reaction to form sodium orthosilicate (Na4SiO4) occurs at significantly lower temperature in comparison with Na–SiO2 reaction. The reaction is kinetically characterized as a largely overlapping multistep reaction, which is composed of at least three reaction steps. On the basis of the observations, the impact of Na2O–SiO2 reaction in the overall SCR and the significance of the conventional kinetic analysis using the Kissinger method are discussed.

Cholesterol protects phosphatidylcholine liposomes from N,N-dimethyldodekanamine N-oxide influence

The interaction of N,N-dimethyl-1-dodekanamine N-oxide (C12(CH3)2NO) with egg yolk phosphatidylcholine (EYPC) liposomes containing cholesterol (CHOL) was studied. The perturbation of CHOL-EYPC bilayers in unilamellar liposomes (ULL) was observed by the leakage of fluorescent probe calcein. Weak leakage is observed at low surfactant concentration cC12NO (minimal perturbation of the bilayer) followed by an intensive leakage at a middle cC12NO (creation of pores). No change in fluorescence intensity was measured at high cC12NO (calcein totally released from liposomes). The higher CHOL amount in the bilayer, the more surfactant is needed to create pores in the bilayer. Solubiliazation of CHOL-EYPC ULL induced by C12NO was studied turbidimetrically. The solubilization curve consists of three parts: saturation of bilayer at low cC12NO (liposomes are preserved), followed by solubilization (liposome - mixed micelle transition) and post-solubilization. The c12NO concentration needed for the onset of the soubilization raises with the increase of nCHOL:nEYPC. The structure of liposomes is still preserved at total calcein release for all nCHOL:nEYPC.

Angiographic Changes in Iris and Iridocorneal Angle Neovascularization After Intravitreal Bevacizumab Injection

To evaluate the effects of the intravitreal (IV) injection of bevacizumab on anterior segment neovascularization using anterior segment angiography. We observed 1 eye with iris and iridocorneal angle neovascularization and 3 with neovascular glaucoma from 4 patients with diabetic retinopathy in 3 eyes and central retinal vein occlusion in 1 eye. Two healthy eyes from 2 other patients served as control eyes. Three eyes, including 1 normal eye, were examined by iris angiography; the other eyes underwent iridocorneal angle angiography with fluorescein (FA) and indocyanine green (IA) using a Heidelberg Retina Angiograph 2. After angiography, 4 eyes with neovascularization were treated with IV bevacizumab (1.25 mg per 0.05 mL) and underwent angiography once more 4 to 6 days after treatment. Iris angiography with indocyanine green revealed many iris vessels, but not dye leaking, in both normal and glaucomatous eyes, and the angiography with fluorescein showed intensive vessel leakage in the iris as well as iridocorneal angle neovascularization, but not in normal eyes. Angle angiography revealed vessel structures with indocyanine green and intensive leakage with fluorescein in the iris and showed iridocorneal angle neovascularization and neovascular glaucoma, whereas no vessel structures appeared with IA or FA in the normal eye. After IV bevacizumab injection in eyes with neovascularization, the vascular structure did not change with IA, but dye leakage remarkably decreased with FA in the iris and angle. However, newly formed vessels in the iris and iridocorneal angle seemed to disappear on slitlamp examination. Intravitreal injection of bevacizumab effectively reduces vascular permeability, whereas newly formed vessels are still present in the iris and iridocorneal angle.

Integrated modelling of nitrate loads to coastal waters and land rent applied to catchment-scale water management

The EU Water Framework Directive (WFD) requires an integrated approach to river basin management in order to meet environmental and ecological objectives. This paper presents concepts and full-scale application of an integrated modelling framework. The Ringkoebing Fjord basin is characterized by intensive agricultural production and leakage of nitrate constitute a major pollution problem with respect groundwater aquifers (drinking water), fresh surface water systems (water quality of lakes) and coastal receiving waters (eutrophication). The case study presented illustrates an advanced modelling approach applied in river basin management. Point sources (e.g. sewage treatment plant discharges) and distributed diffuse sources (nitrate leakage) are included to provide a modelling tool capable of simulating pollution transport from source to recipient to analyse the effects of specific, localized basin water management plans. The paper also includes a land rent modelling approach which can be used to choose the most cost-effective measures and the location of these measures. As a forerunner to the use of basin-scale models in WFD basin water management plans this project demonstrates the potential and limitations of comprehensive, integrated modelling tools.

Characterization of the junction leakage of Ti-capped Ni-silicided junctions

The junction leakage characteristics of Ti-capped nickel-silicided diodes are presented. Ti-capped Ni-silicided devices rapid thermal annealed (RTA) at 400 °C exhibit high sheet resistances and suffer from narrow line effect, which leads to the suspicion that the total phase transformation of NiSi has not yet been achieved. On the other hand, Ti-capped Ni-silicided devices at 500 °C with low sheet resistance have a reverse leakage current comparable to that of pure NiSi. The 120 Å Ni/100 Å Ti-silicided junction at 500 °C has a consistent saturation current compared to that of pure NiSi on the shallow STI intensive leakage structures. On the leakage characteristics, the forward current mechanism is diffusion-dominated, specifically the minority carrier diffusion in the neutral region of the heavily doped side. The shallow p +/ n comb diode has both Schottky contact and diffusion behavior in the forward active region.

Characteristics of herbicidal injury by diphenyl ether herbicides oxyfluorfen and bifenox in Lemna pausicostata Hegelm.

The herbicidal mode of action of diphenyl ethers oxyfluorfen (2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl) benzene) and bifenox (methyl-5-(2, 4-dichlorophenoxy)-2-nitrobenzoate) in Lemna pausicostata HEGELM. was investigated by monitoring an electrolyte leakage and a lipid peroxide decomposition product. Among the diphenyl ethers tested, these two herbicides caused intensive leakage in the plant after a lag period of 4-hr. Thiobarbituric acid-reacting material, product of lipid peroxide decomposition, content in a bathing solution was also increased. Light and oxygen were required for their action and by decreasing the light quantity, the effect of oxyfluorfen was delayed. Exogenously applied antioxidant α-tocopherol, and the scavengers of active oxygen species D-mannitol and hydroquinone partially protected from herbicidal injury. Protection was also partially afforded from phytotoxicity by the photosynthetic electron transport inhibitor, diuron. Although the mechanism of involvement of photosynthesis in the action is still unclear, active oxygen species were suggested to be involved in the initiation of lipid peroxidation.