Elastic behavior of single crystals of ytrria-stabilized zirconia

The single-crystalline elastic constants of yttria-stabilized zirconia (YSZ) have been determined over the temperature range 20-700(DEGREES)C by the pulse-echo-overlap technique. Different crystals of YSZ containing 8.1, 11.1, 12.1, 15.5, and 17.9 mol % Y(,2)O(,3) were examined in the present investigation;The compositional dependencies of the three independent constants at room temperature show that, upon increasing Y(,2)O(,3) content, C(,11) decreases, whereas C(,12) and C(,44) increase. This behavior is best understood from the nature of the interatomic forces of interaction in the fluorite structure of YSZ, wherein the most important contributions are the Coulomb forces and the Born-Mayer repulsive forces of the first nearest neighbors;The high Debye temperatures of the YSZ crystals are characteristic of the strong interatomic interactions. In a harmonic approximation, with neglect of any change in force constants, the Debye temperatures of YSZ crystals should be inversely proportional to the square root of the vibrating masses in the lattice. Such proportionality was found valid for the five YSZ crystals of this investigation;All conventional constants show normal negative temperature dependencies except those of the 8.1 mol % Y(,2)O(,3) alloy, which show nonreproducible behaviors at elevated temperatures;Shear anisotropy in YSZ is pronounced and it decreases with increasing Y(,2)O(,3) content but increases with temperature. Extrapolation of longitudinal and shear constants along different crystallographic directions at room temperature indicates elastic isotropy near 40 mol % Y(,2)O(,3) where a number of investigations have established the presence of an ordered phase (Zr(,3)Y(,4)O(,12)) with a rhombohedral symmetry

Individual and combined effects of antioxidant and salinity on germination characters of rice

A germination experiment was carried out in rice to study the role played by various antioxidants on germination parameters under salt stress in some rice cultivars. The results indicated that the highest germination percentage, rate (days), index and speed were recorded in Sakha 106 cultivar. An increase in the concentration of salt from 100 mM to 300 mM resulted in a reduction in these parameters. Pretreatment of the seeds with Humic acid at 500ppm increased these studied parameters. All studied characters were affected by the interaction between rice cultivars, salinity concentrations and antioxidants. In general, the study suggested that antioxidant pretreatment in rice seeds  can be considered as a potential tool to enhance germination parameters under salinity stress, especially in rice Sakha 106 cultivars

IT governance matter: A structured literature review

The aim of this paper is to critically explore information technology governance (ITG) context, its consequences, its various aspects, its determinants, disclosure, maturity, and challenges. There are some motivations that urge the researchers to carry out this study. First, the review of prior relevant literature reveals a limited number of studies addressing the IT governance context, its consequences, its various aspects, its determinants, and challenges. Second, very little is known about the potential implications of IT governance within the business and how it is significant to the decision-makers (e.g., shareholders, board of directors, executives, etc.). Finally, little research employs the structured literature review (SLR) approach to critically discuss and analyze the IT governance context with its various aspects. The systematic and structured literature review has been employed for a critical analysis of the previous studies on IT governance. It is found that effective ITG has a positive impact on the firm performance in consistent with Altemimi and Zakaria (2017), Hulme (2012). Additionally, it is concluded that there is a positive association between ITG, the trustworthiness and the level of financial disclosure agreeing with (Raghupathi, 2007; Ali & Green, 2007). It is also concluded that the level of ITG disclosure is higher within firms in Europe (67%) than in the US (49%) complementing with Joshi et al. (2013). The adoption of the SLR methodology enables this paper to derive unbiased empirical insights and critique into the current ITG research and to identify possible directions for future ITG research, which may possibly be of interest to the academics, regulators, and professional bodies (e.g., shareholders, board of directors, executives, etc.)

Influence of antioxidants and salinity stress on seedling parameters of some rice cultivars

An investigation was conducted to study the response of antioxidants seed priming on rice cultivars and their effect on germination under salinity levels. The result indicated that the highest in shoot height (cm), root height (cm), seedling vigor index, and other related parameters, relative dry weight% were produced from Sakha 106 cultivar. The lowest seedling height reduction % was produced from Sakha 106 cultivar. An enhancement in salt concentration resulted a reduction in all studied parameters except seedling height reduction %. The results indicated the highest  shoot height (cm), root height (cm),seedling vigor index, shoot fresh and dry weight (mg), root fresh and dry weight (mg), relative dry weight% and seedling height reduction % from which soaking, as pretreatment, in Humic acid at 500ppm. The interactions between cultivars, salinity concentration and antioxidants were insignificant on some traits. It could be concluded that to improve seedling parameters of rice cultivars under salinity stress; it could be recommended that soaking Sakha 106 cultivar seed in Humic acid at 500 ppm for 24 h. It can be used in breeding program to boost production in Egyptian territory

Electromagnetic Nonreciprocity in a Magnetized Plasma Circulator

Nonreciprocal transport of electromagnetic waves within magnetized plasma is a powerful building block towards understanding and exploiting the properties of more general topological systems. Much recent attention has been paid to the theoretical issues of wave interaction within such a medium, but there is a lack of experimental verification that such systems can be viable in a lab or industrial setting. This work provides an experimental proof-of-concept by demonstrating nonreciprocity in a unit component, a microwave plasma circulator. We design an E-plane Y junction plasma circulator operating in the range of 4 to 6 GHz using standardized waveguide specifications. From both simulations and experiments, we observe wide band isolation for the power transmission through the circulator. The performance and the frequency band of the circulator can be easily tuned by changing the plasma density and the magnetic field strength. By linking simulations and experimental results, we estimate the plasma density for the device.Comment: Revision 2: Added a section to introduce the scattering matrix in a nonreciprocal microwave systems with additional references. Fixed typo on greek letters. Swapped fig 1 and 2 for clarity. Defined the technical terms in Section II to avoid confusion. Updated the correct value for the minimum normalized isolated power when a positive magnetic field was applie

Germination and Seedling Characters as Influenced by Sunflower Hybrids, Nitrogen Fertilizer Rates and Hill Spacing

In order to study the performance of some sunflower genotypes to nitrogen fertilizer rates and plant population density to germination and seedling parameters. A laboratory experiment conducted in the Agronomy Department seed lab, Faculty of Agriculture, Mansoura University, Egypt during March and April 2017.The goals of this study aimed to study the effect of sunflower hybrids, nitrogen fertilizer rates and hill spacing on germination and seedling characters.The results indicated that Nsovak genotype recorded the highest values of abnormal seedling percentage. Highest mean germination time was obtained from MS.sirena F1 genotype. The highest coefficient of velocityand value of the vigour was produced from Biest Brima genotype without significant differences with sown Nsovak genotype.The results indicated that increasing nitrogen fertilizer rates from 72, 120 and 168 kg N/ha significantly increased mean germination timeandvalue of the vigour. The highest coefficient of velocity percentage produced from addition nitrogen fertilizer at 120 Kg/ha.The results designated that increasing hill spacing from 15, 20 and 25 cm reduced germination percentage and mean germination time, however, significantly increased coefficient of velocity anddead seed percentages and value of the vigour.It could be concluded that sown Nsovak genotype at hill spacing of 15 cm and fertilizing with 120 kg N/ha enhanced seed germination and viability

Response of Some Sunflower Hybrids (Helianthus annuus l.) to Different Nitrogen Fertilizer Rates and Plant Densities

In order to improve sunflower productivity, this investigation aimed to study the performance of some genotypes to different doses of nitrogen and plant population density on seed yield and yield components. Two field Experiments carried out on the Experimental Farm of the Sakha Agriculture Research Station during 2015 and 2016 seasons. The objective of this study aimed to investigate the performance of some sunflower hybrids to different nitrogen fertilizer rates and plant population densities to growth, yield components, seed yield and its quality.The results indicated that tallest plants, highest leaves number/plant, number of achenes/head and highest values of head diameter were obtained from MS.sirena F1 genotype. Biest Brima genotype recorded the highest values of leaf area. The highest weight of 1000 seed and seed yield/ha were recorded from Nsovak genotype.The increases in nitrogen fertilizer rates to 168 Kg N/ha produced tallest plants,thick stems (cm), the highest leaves number/plant, leaf area (cm2), number of achenes/head, head diameter (cm), 1000 achene weight (gm) and achene yield (Kg/ha) in both seasons. It could observed that increasing nitrogen fertilizer from 72 to 168 Kg N/ha significantly increased seed yield by 12.0 and 11.6 % in the first and second seasons, respectively. Increasing hill spacing from 15, 20 and 25 cm produced thickness stem, highest number of leaves/plant, highest values of leaf area, maximum number of achenes/head, head diameter and weight of 1000 achene. The tallest plants and highest and achene yield were produced from 20cm hill spacing. It could concluded that increasing nitrogen fertilizer from 72 to 168 Kg N/ha and sown Nsovak genotype at dense hill spacing of 15 cm between plants maximized seed yield per unite area

Strengthening of Concrete Beams Using FRP Composites

Finite element analysis (FEA) is used to predict the behavior of reinforced concrete beams strengthened with fiber reinforced polymer (FRP). To verify and measure the accuracy of the FEM model, the current model results were compared with both experimental and theoretical available results. Four beams were studied simulating the Horsetail Creek Bridge, Oregon, USA. The first one is a control beam with no strengthening fiber.The second beam is strengthened with carbon fiber reinforced polymer (CFRP) oriented along the length of the beam to reinforce the flexure behavior. The third beam is wrapped with glass fiber reinforced polymer(GFRP) laminates representing the shear beam. The fourth one is strengthened with CFRP and GFRP laminates representing the flexure-shear beam.The load-strain for concrete, steel and fiber as well were represented and compared. In addition, the load deflection curves and crack patterns were developed and represented. The results showed that the modeling process was accurate in simulating the tested beams. It was also clear that using FRP in strengthening reinforced concrete beams is an effective method in improving both shear and flexural behavior of the beams