636 research outputs found
Application of sand and geotextile envelope in subsurface drip irrigation
Subsurface drip irrigation is a technology used for better management of irrigation water. This technique is more desirable in arid and semi-arid region, because of decreasing soil surface evaporation and more efficiency of irrigation system in comparison with the other irrigation systems. Inaddition, this system is a safer way for treated wastewater (TWW) reuse in irrigation lands. But roots and clay particles can clog drip emitters in systems buried below the soil surface. In this paper, sand and geotextile filtration methods have been suggested for solving root intrusion and biological plugging problems for subsurface drip applications. Sand envelope around the emitters has been recommended for deeper root zone and long term application of system, while geotextile envelope is suitable for seasonal crops with shallow root.Key words: Subsurface drip irrigation, sand and geotextile, emitters
Glycated hemoglobin measurements from dried blood spots: Reliability and relation to results obtained from whole blood samples
Background: Main objective was to measure glycated hemoglobin (HbA1c) in dried blood spots on paper filter and in whole blood samples in diabetic patients to evaluate relationship between two methods and their respective reliability. Methods: The 20�10 μl of venous blood samples of 33 diabetics were blotted onto the filter paper allowed to dry at room temperature and then stored at 25°C and 4°C. HbA1c was measured via the Turbidimetric Inhibition Immunoassay Technique. The relation was evaluated with correlation and linear regression tests using STATA software and SPSS. Agreement between the results obtained from the dried blood spots and others was evaluated using the Bland and Altman. The pitman's permutation test was also employed to compare the difference in variance. Results: A high positive correlation was detected between whole blood samples and dried blood spots stored at 4°C (r2 =0.90) and at 25°C (r2 = 0.95). The Bland and Altman graphs, as well as the Pitman tests, showed statistically significant differences in variability between the values obtained from whole blood samples and those derived from dried spots stored at 4°C (p=0.05) or 25°C (p=0.004). Conclusion: HbA1c measurements from dried blood spots on the filter paper yielded reliable results. That the Hitachi autoanalyzer is available in most countries renders this assay less costly than the High Performance Liquid Chromatography Method (HPLC). In addition, the filter paper method for Immuno-turbidimetric estimations of HbA1c at different temperatures is reliable and may be particularly useful in outpatient diabetes clinic
An Empirical Relation Between The Large-Scale Magnetic Field And The Dynamical Mass In Galaxies
The origin and evolution of cosmic magnetic fields as well as the influence
of the magnetic fields on the evolution of galaxies are unknown. Though not
without challenges, the dynamo theory can explain the large-scale coherent
magnetic fields which govern galaxies, but observational evidence for the
theory is so far very scarce. Putting together the available data of
non-interacting, non-cluster galaxies with known large-scale magnetic fields,
we find a tight correlation between the integrated polarized flux density,
S(PI), and the rotation speed, v(rot), of galaxies. This leads to an almost
linear correlation between the large-scale magnetic field B and v(rot),
assuming that the number of cosmic ray electrons is proportional to the star
formation rate, and a super-linear correlation assuming equipartition between
magnetic fields and cosmic rays. This correlation cannot be attributed to an
active linear alpha-Omega dynamo, as no correlation holds with global shear or
angular speed. It indicates instead a coupling between the large-scale magnetic
field and the dynamical mass of the galaxies, B ~ M^(0.25-0.4). Hence, faster
rotating and/or more massive galaxies have stronger large-scale magnetic
fields. The observed B-v(rot) correlation shows that the anisotropic turbulent
magnetic field dominates B in fast rotating galaxies as the turbulent magnetic
field, coupled with gas, is enhanced and ordered due to the strong gas
compression and/or local shear in these systems. This study supports an
stationary condition for the large-scale magnetic field as long as the
dynamical mass of galaxies is constant.Comment: 23 pages, 4 figures, accepted for publication in the Astrophysical
Journal Letter
Management ofwater content of soil in cultivation of greenhouse cucumber (Cucumis sativus L, Nasim variety) in Isfahan- Iran
Measurement and control of water content of soil is an essential factor in irrigation management, to apply the best management practice for reducing water consumption and improving product quality. The water content of soil is an important factor in greenhouse where it is directly related to the total amount of water consumed for irrigation. Since cucumbers (Cucumis sativus L, Nasim variety) is considered as the main and much used summer crop in Iran, which are extremely sensitive to adverse conditions particularly water stress, determination and supply of water is vital for this plant. To this end, maximum allowable depletion (MAD) should be determined. This experiment was conducted in the research greenhouse (Plastic Covered) of Islamic Azad University in Khorasgan, Isfahan, during a period of five months. This project was implemented in the framework of three 40, 60, and 80 cm bar water suction treatments with three replications using tensiometer. Before treatment application, water content of soil was determined in weight. MAD in 40, 60, and 80 cm bar treatments was 22, 32 and 50%, respectively. Statistical results and mean comparison demonstrated that MAD of 22 and 32% led to a significant yield increase (P<0.001), while MAD of 50% had the least yield. The results reveal that there was a significant difference between MAD of 22 and 32% in increasing leaf area index (LAI) (P<0.001).Key words: Maximum allowable depletion, greenhouse cucumber, tensiometer, leaf area index
A Dynamic Collusion Analysis Framework Considering Generation and Transmission Systems Maintenance Constraints
Capacity withholding of generation companies is an important issue in market monitoring procedures. The capacity withholding can be intensified in the transmission and generation constrained system. The strategic maintenance of market participants can impose multiple constraints on the system and changes the wholesale electricity market prices. The strategic maintenance of transmission and generation facilities is known as dynamic capacity withholding (DCW) and all of the market-monitoring units need algorithms to detect and reduce DCW. In this paper, a new dynamic capacity withholding index is presented. The method is analyzed on the IEEE 30, 57-bus test system. The numerical results show the effectiveness of the proposed index.©2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.fi=vertaisarvioitu|en=peerReviewed
Finite-dimensional representation of the quadratic algebra of a generalized coagulation-decoagulation model
The steady-state of a generalized coagulation-decoagulation model on a
one-dimensional lattice with reflecting boundaries is studied using a
matrix-product approach. It is shown that the quadratic algebra of the model
has a four-dimensional representation provided that some constraints on the
microscopic reaction rates are fulfilled. The dynamics of a product shock
measure with two shock fronts, generated by the Hamiltonian of this model, is
also studied. It turns out that the shock fronts move on the lattice as two
simple random walkers which repel each other provided that the same constraints
on the microscopic reaction rates are satisfied.Comment: Minor revision
Applying Bayesian Optimization with Gaussian Process Regression to Computational Fluid Dynamics Problems
Bayesian optimization (BO) based on Gaussian process regression (GPR) is
applied to different CFD (computational fluid dynamics) problems which can be
of practical relevance. The problems are i) shape optimization in a lid-driven
cavity to minimize or maximize the energy dissipation, ii) shape optimization
of the wall of a channel flow in order to obtain a desired pressure-gradient
distribution along the edge of the turbulent boundary layer formed on the other
wall, and finally, iii) optimization of the controlling parameters of a
spoiler-ice model to attain the aerodynamic characteristics of the airfoil with
an actual surface ice. The diversity of the optimization problems, independence
of the optimization approach from any adjoint information, the ease of
employing different CFD solvers in the optimization loop, and more importantly,
the relatively small number of the required flow simulations reveal the
flexibility, efficiency, and versatility of the BO-GPR approach in CFD
applications. It is shown that to ensure finding the global optimum of the
design parameters of the size up to 8, less than 90 executions of the CFD
solvers are needed. Furthermore, it is observed that the number of flow
simulations does not significantly increase with the number of design
parameters. The associated computational cost of these simulations can be
affordable for many optimization cases with practical relevance
Tea, Coffee, and Milk Consumption and Colorectal Cancer Risk
Background: Data regarding the effects of tea, coffee, and milk on the risk of colorectal cancer are inconsistent. We investigated associations of tea, coffee, and milk consumption with colorectal cancer risk and attempted to determine if these exposures were differentially associated with the risks of proximal colon, distal colon, and rectal cancers. Methods: Data from 854 incident cases and 948 controls were analyzed in a case-control study of colorectal cancer in Western Australia during 2005–07. Multivariable logistic regression was used to analyze the associations of black tea (with and without milk), green tea, herbal tea, hot coffee, iced coffee, and milk with colorectal cancer. Results: Consumption of 1 or more cups of herbal tea per week was associated with a significantly decreased risk of distal colon cancer (adjusted odds ratio, 0.37; 95% CI, 0.16–0.82; P[subscript]Trend = 0.044), and consumption of 1 or more cups of iced coffee per week was associated with increased risk of rectal cancer (adjusted odds ratio, 1.52; 95% CI, 0.91–2.54; P[subscript]Trend = 0.004). Neither herbal tea nor iced coffee was associated with the risk of proximal colon cancer. Hot coffee was associated with a possible increased risk of distal colon cancer. Black tea (with or without milk), green tea, decaffeinated coffee, and milk were not significantly associated with colorectal cancer risk. Conclusions: Consumption of herbal tea was associated with reduced risk of distal colon cancer, and consumption of iced coffee was associated with increased rectal cancer risk
Plasmon-Mediated Drilling in Thin Metallic Nanostructures
Tetrahedral nanopyramids made of silver and gold over ITO/glass surfaces are fabricated. Our protocol is based on nanosphere lithography (NSL) with the deposition of thicker metal layers. After removing the microspheres used in the NSL process, an array of metallic tetrahedral nanostructures of ~350-400 nm height is formed. The reported procedure avoids the use of any stabilizing surfactant molecules that are generally necessary to segregate the individual particles onto surfaces. We focus here on the optical and the physical properties of these plasmonic surfaces using near-field spectroscopy in conjunction with finite difference time domain (FDTD) modeling of the electric field. Remarkably, FDTD shows that the localized surface plasmon resonance is confined in the plane formed by the edges of two facing pyramids that is parallel to the polarization of the impinging excitation laser. The variable gap between the edges of two adjacent pyramids shows a broader localized surface plasmon and larger specific surface as opposed to the usual nanotriangle array. Localized enhancement of the electric field is experimentally investigated by coating the plasmonic surface with a thin film of photosensitive azopolymer onto the surface of the nanopyramids. The reported deformation upon radiation of the surface topography is visualized by atomic force microscopy and suggests the potentiality of these 3D nanopyramids for near-field enhancement. This last feature is clearly confirmed by surface-enhanced Raman scattering measurement with 4-nitrothiophenol molecules deposited on the pyramid platforms. The potentiality of such 3D nanostructures in plasmonics and surface spectroscopy is thus clearly demonstrated
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