Reflection and radiation of capillary-gravity water waves

The necessary edge condition, which is used here, includes both dynamic variation of the contact angle and contact angle hysteresis. It is given by making the slope of the free surface at contact proportional to its velocity, however, viscosity has been ignored throughout. Six problems are studied. The first one is the damping of capillary-gravity waves inside a vertical and axisymmetric cylinder, where the frequency of these waves are calculated. The second problem is concerned with the study of the waves produced by a vertically oscillating cylinder, and determining the surface elevation, at both on and large distances away from the cylinder. The third problem is the horizontal oscillation of a cylinder partially immersed in the fluid, such that the cylinder and the fluid are both of infinite or finite depth, where again the surface elevation from the free surface at large distances and on the edge of the cylinder are evaluated. The fourth problem studies the scattering of a capillary-gravity wave by a surface-piercing circular cylinder, and the depending condition applied at the contact line between the fluid and the obstacle. Using a model for this condition that incorporates the effect of dynamic contact-angle variation, the wave field close to the obstacle and at large distances away are determined. The fifth problem studied, concerns the vertical and horizontal oscillation of a vertical cylinder, as well as the scattering of waves made by it, in shallow water. When the depth of the fluid is small compared with the wavelength, the simplifications of shallow-water theory can be applied and the results arrived at more readily than by the methods used for arbitrary depths. In each case, the surface elevation of the radiated waves at large distances away from the cylinder is obtained, as well as some special cases (when some of the parameters have extreme values). The sixth problem studied is the waves produced by a vertical plate, when it is forced to oscillate horizontally. The length of the plate is considered to be finite and the fluid is either of infinite depth or of the same depth as the length of the plate. Both the steady-state and the transient motion are studied. However, when the depth of the fluid is small, the simplifications of shallow-water theory can be applied. The surface elevation at large distances away and the amplitude of these waves are calculated for the cases of vertically moving boundary and for the reflection of an incident wave

Chemical Synthesis of Polypyrrole Nanotubes for Neural Microelectrodes

AbstractA low impedance electrode/tissue interface is critically important for neural microelectrodes recording to maintain signal quality. In this study, polypyrrole (PPy) nanotubes used to decrease the interface impedance. PPy nanotubes were chemically synthesized inside the alumina template. SEM analysis showed 70nm inside diameter of nanotubes. Electrochemical impedance spectroscopy (EIS) tests were performed for impedance measurement of PPy nanotubes coated microelectrode surface. The results showed that the impedance of the microelectrodes with PPy nanotubes coatings was four order of magnitude lower than the electrodes without coating in the neural frequency. EIS results also showed significant decrease in impedance of PPy nanotubes rather than PPy thin films

Terminal flower 1(TFL1) homolog genes in dicot plants

Terminal flowering1 (TFL1) is an important gene responsible for time of flowering in Arabidopsis thaliana. It belongs to phosphtidyl ethanolamine binding protein domain PEBP gene family. Throughout the past decade, genetic studies have found out several TFL1 like genes in dicots and monocots plants. In this paper, current advances in TFL1 homolog isolated from different dicot species, has been addressed. Arabidopsis thaliana, Antirrhinum majus, Brassica naapus, Citrus sinensis L, Pisum sativum, Vitis vinifera L, Beta palonga, Lotus japonicus, Lycopersicon esculentum, Impatiens balsamina, populus trichocarpa, Malus xdomestica, Pyrus pyrifolia, Pyrus communis, Cydonia oblonga, Chaenomeles sinensis, Cucumis sativus, Gossypium hirsutum,Capsicum annuum L.and Eriobotrya japonica are dicot plants which their TFL1 homologs will be discused here. Moreover, similarity and differences between them and other known genes, have been compared

Husbands' Perception of Environmental Characteristics During Participation in Physiologic Delivery

Objective: Nowadays, the presence of husbands during the childbirth process is regarded as an important factor that can contribute to lower rate of the C-section, better success of physiologic delivery and higher satisfaction in childbirth experience. Considering the special sociocultural characteristics of the Iranian society, this method requires accurate assessment to be practical and effective. The aim of this research was finding out how husbands perceive the environmental and physical characteristics of delivery spaces via studying these physical characteristics, exploring them through husbands’ perception and finally discovering the mechanism behind formation of this perception. Materials and methods: First, the conceptual model of the study was developed after a review of the physiologic childbirth literature. Then, a research questionnaire was designed and distributed among 120 husbands who recently had the experience of accompanying their wives during physiologic childbirth. Results: The results showed that light, color and temperature play a significant role in husbands’ perception of delivery spaces under the special psychological conditions and stress that they experience during the childbirth. Designer should pay due attention to these three factors when designing the structure of childbirth spaces. Conclusion: Promoting the environmental quality of the physiologic delivery room based on husband's perception can help mothers and medical staff better manage childbirth pain which is an integral part of natural childbirths

Effect of Process Conditions on Phase Stability and Morphology in Manganese Oxide Nano-Materials

The properties of manganese oxide nano-materials are dictated by the structure of the particular phases adopted, and by the morphology of the particles or aggregates formed. In this dissertation a combination of processing and advanced characterization studies has been performed to investigate two key aspects of this system: the role of the surfactant in the synthesis of self-assembled mesoporous manganese oxides, and the effect of post-synthesis heat treatment on the phase stability in manganese oxide nanoparticles. The first part concerns UCT manganese oxides in which the materials are synthesized via an inverse micelle templating process. The objective was to develop an understanding of the factors that control the morphology, microstructure, and desulfurization behavior of these materials. Samples were synthesized using four different Pluronic surfactants, and these were characterized using a combination of XRD, SAXS, SEM, S/TEM, BET, and sulfur adsorption techniques. While all the as-synthesized samples exhibited similar hierarchical microstructures, consisting of assemblies of Mn3O4 and/or Mn5O8 nanoparticles, the sizes and shapes of these nanoparticles were different for each sample. These effects led to pronounced differences in the pore size distributions. The sulfur adsorption tests revealed a transformation of the mesoporous manganese oxide to a dense manganese sulfide phase, which results in a volumetric expansion, densification, and rapid decay in the sorption capacity after the breakthrough point. The data suggest that the variation in the structure and properties of these materials is related to ratio of the PEO and PPO chain segment lengths in the Pluronic surfactants used. Thus, the PEO:PPO ratio dictates the volume, shape and assembly of the inverse micelles in the synthesis and is a key process design variable in UCT materials. The focus of the second part is on the phase transformations in manganese oxide nanoparticles upon heating in inert and oxidizing environments. This study involved performing controlled heating experiments on electron-transparent amorphous monodisperse manganese oxide nanoparticles at different temperatures and under different oxygen partial pressures. Samples exposed ex situ were evaluated using X-ray scattering and electron microscopy techniques to reveal the structure, morphology and oxidation states for the manganese oxide phases present. Upon heating in Ar at temperatures up to 1300 ºC, the samples went through a series of phase transformations to Mn2O3, Mn3O4, and MnO corresponding to a gradual reduction of manganese from 3+ to 2+. Upon heating to 1300 ºC in air, the latter transformation did not occur, indicating that Mn3O4 is the stable phase at higher temperatures under oxidizing conditions. In situ TEM heating experiments were used to investigate the dynamic evolution of the microstructure at high spatial resolution under vacuum. In experiments performed at high heating rates, a transformation to MnO was observed, while at lower heating rates the samples transformed to Mn3O4. These observations reveal the roles of temperature, oxygen partial pressure, and heating rate on the phase transformations in manganese oxide upon heating, and serve as a guide for designing thermal processing routes to obtain the manganese oxide phase desired for a particular application