scholarly journals Sugar Transport in a Merging Phloem Vessels: A Hydrodynamic Model

2021 ◽  
pp. 1-11
Author(s):  
W. I. A. Okuyade ◽  
T. M. Abbey ◽  
M. E. Abbey

Green plants are the major tappers of the energy from the sun. The collected solar energy in the form of light is used to activate the chemical reaction occurring in matured leaves between carbon dioxide and water, leading to the synthesis of sugar (chemical energy). Two main transport processes are involved in the transport of mineral salt water from the soil through the roots, via the trunk and branches to the leaves where photosynthetic activity occurs, and the translocation of sugar from the leaves to where they are needed and possibly, stored. The xylem vessels bear the absorbed mineral salt water while the phloem vessels bear the manufactured sugar. In this study, neglecting the effects of occlusion and clogging of the phloem channels, we investigate the transport of sugars in the merging phloem vessels using the hydrodynamic approach. The model is designed using the Boussinesq approximation and solved semi-analytically using the regular perturbation series expansion solutions and Mathematica 11.2 computational software. Expressions for the concentration, temperature, and velocity are obtained and presented quantitatively and graphically. The results show among others, that increase in the merging angle causes a reduction in the concentration, temperature, and velocity profiles. However, there exists fluctuations in the concentration and temperature structures.

2005 ◽  
Vol 23 (5) ◽  
pp. 1931-1941 ◽  
Author(s):  
I. M. Robinson ◽  
G. M. Simnett

Abstract. We examine the solar energetic particle event following solar activity from 14, 15 April 2001 which includes a "bump-on-the-tail" in the proton energy spectra at 0.99 AU from the Sun. We find this population was generated by a CME-driven shock which arrived at 0.99 AU around midnight 18 April. As such this population represents an excellent opportunity to study in isolation, the effects of proton acceleration by the shock. The peak energy of the bump-on-the-tail evolves to progressively lower energies as the shock approaches the observing spacecraft at the inner Lagrange point. Focusing on the evolution of this peak energy we demonstrate a technique which transforms these in-situ spectral observations into a frame of reference co-moving with the shock whilst making allowance for the effects of pitch angle scattering and focusing. The results of this transform suggest the bump-on-the-tail population was not driven by the 15 April activity but was generated or at least modulated by a CME-driven shock which left the Sun on 14 April. The existence of a bump-on-the-tail population is predicted by models in Rice et al. (2003) and Li et al. (2003) which we compare with observations and the results of our analysis in the context of both the 14 April and 15 April CMEs. We find an origin of the bump-on-the-tail at the 14 April CME-driven shock provides better agreement with these modelled predictions although some discrepancy exists as to the shock's ability to accelerate 100 MeV protons. Keywords. Solar physics, astrophysics and astronomy (Energetic particles; Flares and mass ejections) – Space plasma physics (Transport processes)


2021 ◽  
Vol 2114 (1) ◽  
pp. 012019
Author(s):  
Adi Al A’assam ◽  
M.W. Ahamd

Abstract When studying the water reality and calculating the increase in the quantities of water per year, we find that there is another way to increase the percentage of water, and that is through optical reproduction. For a detailed explanation of the location of water on Earth, see the map and the data table shown below. Note that the world’s add up to water supply is almost 1.387 million cubic kilometers (332.6 cubic miles) of wate, of which more than 96% is salt water. As for fresh water, more than 96% are trapped by rivers and glaciers, and 30% are on the ground. As for the freshwater resources represented in rivers and lakes, they constitute about 93,100 cubic kilometers (22,300 cubic miles), which is about 1/150 of 1% of the total water. Rivers and lakes still make up most of the water sources that people use daily. The amount of water stored in the oceans for long periods is much more than that which moves through the water cycle. The total water supply worldwide is 1,386,000,000 cubic kilometers (321,000,000 cubic miles), of which 1,338,0, 000 cubic kilometers (332,500,000 cubic miles) are stored in the oceans at a rate of 95%, as the oceans give almost 90% of the water. Dissipated that goes to the water cycle. The photonic cloning resulting by the sun contributes to the consistency of water level. Indeed, the consistency of ocean water depends not only on the natural cycle of evaporation process of those waters to return to the oceans again, but also on the photonic cloning resulting by the sun, as experiment has vividly shown.


Author(s):  
Alberto Plata Montero

RESUMEN: El Valle Salado de Añana se ubica en el País Vasco, a unos treinta kilómetros de su capital, Vitoria-Gasteiz. Se trata de un ejemplo notable de la interacción del hombre con el medio en la formación de un paisaje singular cuyo origen se remonta al Neolítico, conservándose y manteniéndose vivo durante más de 7.000 años, en una evolución dinámica que le ha permitido adaptarse a unos ritmos de producción que aseguran su sustentabilidad. En el proceso se han utilizado los mínimos recursos con el máximo rendimiento de forma absolutamente sostenible y ecológica aplicando una tecnología ingeniosa. El resultado es un paisaje humanizado de 12 hectáreas, donde cuatro kilómetros de canales de madera conducen el agua salada desde los manantiales a las más de cinco mil plataformas de producción escalonadas construidas con piedra, madera y arcilla, donde el sol, el viento y los salineros trabajan de forma conjunta para obtener una de las mejores sales del mundo: la Sal de Añana. El Valle Salado es paradigma de una sabia y discreta intervención humana sobre el entorno, aprovechando éste hasta el límite. Un maravilloso ejemplo de sabiduría popular que se plasma en un paisaje de increíble pero sencilla belleza, ejemplo de sostenibilidad y de respeto ecológico, que ha sabido también incorporar las nuevas exigencias de calidad, gestión y usos de la sociedad contemporánea. Una sociedad que está perfectamente imbricada con él, que lo vive, lo explota, lo mantiene y lo disfruta, implicándose enérgicamente en su gestión y que, orgullosa de él, hace partícipe al resto de la humanidad.ABSTRACT:The Salt Valley of Añana is located in the Basque Country, about thirty kilometers from its capital, Vitoria-Gasteiz. This is a remarkable example of the interaction of man with the environment in the formation of a unique landscape whose origin dates back to the Neolithic, preserved and kept alive for more than 7,000 years, in a dynamic evolution that has allowed it to adapt to rhythms of production that ensure its sustainability. In the process, the minimum resources have been used with the maximum performance in an absolutely sustainable and ecological way applying an ingenious technology. The result is a humanized landscape of 12 hectares, where four kilometers of wooden canals lead the salt water from the springs to the more than five thousand staggered production platforms built with stone, wood and clay, where the sun, the wind and the “Salineros” (saltmen) work together to obtain one of the best salts in the world: Añana Salt. The Salt Valley is a paradigm of a wise and discreet human intervention on the environment, taking advantage of it to the limit. A wonderful example of popular wisdom that is reflected in a landscape of incredible but simple beauty, an example of sustainability and ecological respect, which has also managed to incorporate the new demands of quality, management and uses of contemporary society. A society that is perfectly intertwined with him, that lives it, exploits it, maintains it and enjoys it, implying itself vigorously in his management and that, proud of him, makes the rest of humanity participate.


1990 ◽  
Vol 121 ◽  
pp. 437-448
Author(s):  
A. Baglin ◽  
Y. Lebreton

AbstractObservations of the surface abundances of lithium, beryllium and helium-3 in the Sun and in solar-type stars of different ages should be interpreted in a coherent way. The abundance of lithium at the surface of a star decreases slowly with age; for stars of the same age it decreases with mass and a dependence on the rotation velocity is suggested. The solar surface lithium is depleted by a factor of 100 relative to the cosmic abundance while an He-3 enrichment of 15% at the solar surface during evolution is suggested.Observations favour the hypothesis of a slow transport process at work between the outer convective zone and the radiative interior of these stars. Orders of magnitude of the transport coefficient as well as its dependence upon the physical parameters can be inferred from surface abundances of light elements, but at the moment we are far from producing a completely consistent modelization.


2001 ◽  
Vol 183 (10) ◽  
pp. 3224-3236 ◽  
Author(s):  
Gordana M. Djordjevic ◽  
Jason H. Tchieu ◽  
Milton H. Saier

ABSTRACT The heterofermentative lactic acid bacterium Lactobacillus brevis transports galactose and the nonmetabolizable galactose analogue thiomethyl-β-galactoside (TMG) by a permease-catalyzed sugar:H+ symport mechanism. Addition of glucose to L. brevis cells loaded with [14C]TMG promotes efflux and prevents accumulation of the galactoside, probably by converting the proton symporter into a uniporter. Such a process manifests itself physiologically in phenomena termed inducer expulsion and exclusion. Previous evidence suggested a direct allosteric mechanism whereby the phosphocarrier protein, HPr, phosphorylated at serine-46 [HPr(Ser-P)], binds to the galactose:H+ symporter to uncouple sugar transport from proton symport. To elucidate the molecular mechanism of inducer control in L. brevis, we have cloned the genes encoding the HPr(Ser) kinase, HPr, enzyme I, and the galactose:H+ symporter. The sequences of these genes were determined, and the relevant phylogenetic trees are presented. Mutant HPr derivatives in which the regulatory serine was changed to either alanine or aspartate were constructed. The clonedgalP gene was integrated into the chromosome ofBacillus subtilis, and synthesis of the mutant HPr proteins in this organism was shown to promote regulation of GalP, as expected for a direct allosteric mechanism. We have thus reconstituted inducer control in an organism that does not otherwise exhibit this phenomenon. These results are consistent with the conclusion that inducer exclusion and expulsion in L. brevis operates via a multicomponent signal transduction mechanism wherein the presence of glycolytic intermediates such as fructose 1,6-bisphosphate (the intracellular effector), derived from exogenous glucose (the extracellular effector), activates HPr(Ser) kinase (the sensor) to phosphorylate HPr on Ser-46 (the messenger), which binds to the galactose:H+ symporter (the target), resulting in uncoupling of sugar transport from proton symport (the response). This cascade allows bacteria to quickly respond to changes in external sugar concentrations. Understanding the molecular mechanism of inducer control advances our knowledge of the link between metabolic and transport processes in bacteria.


Author(s):  
Joel Jiménez-Lozano ◽  
Mihir Sen ◽  
Patrick Dunn

Physiological fluids in human or animals are, in general, propelled by the continuous periodic muscular contraction or expansion (or both) of the ducts through which the fluids pass, a phenomenon known as peristalsis. Peristaltic mechanisms may be involved in the swallowing of food through the esophagus, vasomotion of small blood vessels, spermatic flows in the ductus efferentes, embryo transport in the uterus, and transport of urine through the ureters, among others [1]. Peristaltic fluid flow can be accompanied by solid particles. In this work the Basset-Boussinesq-Oseen (BBO) equation will be employed to analyze particle motion in peristaltic fluid flow, this model considers motion of a small spherical particle suspended in a nonuniform fluid flow and diverse forces are considered. In ureteral peristaltic flow, fluid being transported is essentially Newtonian and incompressible. Ureteral peristaltic flow is sometimes accompanied by particles such as stones or bacteria. In the present study, the geometrical form of the peristaltic wave will be taken to be sinusoidal. The governing equations are Navier-Stokes for the fluid and momentum for the particle (BBO equation). A regular perturbation series in which the variables are expanded in a power series of the wavenumber (ε = πRw/λ) is used to solve the fluid problem. One-way coupling between the fluid and particles is assumed.


2001 ◽  
Vol 8 (4/5) ◽  
pp. 223-239 ◽  
Author(s):  
V. I. Vlasenko ◽  
K. Hutter

Abstract. Results of an experimental and theoretical study of the interaction of a first mode internal solitary wave with a localised bottom topography (sill) are presented. Laboratory experiments have been performed in a 10m long and 0.33m wide channel filled with a stratified fluid. The interface between the two layers (fresh and salt water) is diffuse and has a finite thickness. Soliton-type disturbances of the interface having characteristics of the first baroclinic mode are generated at one channel end. They move along the channel and encounter an underwater obstacle (sill) in the middle of the channel, where they break into reflected and transmitted waves. Two types of internal waves are produced by the interaction: a fast first mode internal soliton and a slower (by a factor of approximately 3) second mode soliton-like wave. A numerical model, based on the two-dimensional Navier-Stokes equations in the Boussinesq approximation, is used tore produce the laboratory experiment. The detailed analysis of the horizontal and vertical structures of transmitted and reflected waves showed that the fast reflected and transmitted waves observed in the experiment can be interpreted as a first mode internal solitary wave whose characteristics are very close to those of the K-dV solitons. It is also demonstrated that the slow speed waves, generated during the interaction behind the first fast wave have vertical and horizontal structures very close to the second mode internal K-dV solitons.


Author(s):  
Oluwole Daniel Makinde ◽  
Z.H. Khan ◽  
W.A. Khan ◽  
M.S. Tshehla

The magneto-hemodynamic laminar flow of a conducting incompressible viscous nanofluid (blood) through a channel of slowly varying width under a transverse magnetic is investigated using perturbation and numerical methods. For this purpose, Buongiorno’s model is employed for the analysis in four different channels namely, convergent, divergent, locally constricted and wavy channels. Oberbeck-Boussinesq approximation is used and the partial differential equations are solved using perturbation series method. For validation, the governing differential equations are also solved numerically. Both perturbation and numerical results are compared and are found in good agreement. The effects of pertinent parameters on the fluid flow, heat and mass transfer in the selected channels are analyzed for special cases. The results show that both thermal and solutal Richardson numbers have opposite behaviour for skin friction, heat and mass transfer in each channel.


2004 ◽  
Vol 215 ◽  
pp. 457-466 ◽  
Author(s):  
G. Michaud ◽  
J. Richer ◽  
O. Richard

Abundance anomalies in the Sun, main sequence F, A and B stars, turnoff Pop II stars, the horizontal branch and white dwarfs are caused at least partly by particle transport processes. Detailed evolutionary models have been calculated for most of those objects taking into account the gravitational settling, thermal diffusion and radiative accelerations of 28 isotopes (24 atomic species). These will be used together with the observed abundances to put constraints on the mixing that rotationnally induced turbulence may lead to. The link between abundance anomalies and rotation on the HB is explained by the variation with log g of the ratio of the Eddington-Sweet and atomic diffusion velocities.


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