Hydrogen Evolution Reaction on Thermodiffusion Treated Nickel-Implanted Titanium Electrodes

Implating ions with high-energy into the surface of electrode can introduce catalytically active elements, and thus form a large number of active centers to improve the catalytical activity. As a result of implanting nickel ions into Ti-electrode we get a overpotential decrease of hydrogen evolution by 245 mV and the electrode was much more active than the unimplanted one. The experiment shows that the catalytical activity of the electrodes raises with the increase of the surface nickel ions concentration. The maximum concentration of ions were not on the electrode surface, as the deep distribution of the

Global Attractors for the One-dimensional Model of Thermodiffusion with Second Sound

In this paper we investigate the global attractors for the one-dimensional linear model of thermodiffusion with second sound. Using the method of contractive functions, we obtain the asymptotically compact of the semigroup and the existence of the global

Ionic thermoelectric materials and devices

The tremendous amount of wasted heat from solar radiation and industry dissipation has motivated the development of thermoelectric concepts that directly convert heat into electricity.The main challenge in practical applications for thermoelectrics is the high cost from both materials and manufacturing.Recently,breakthrough progresses in ionic thermoelectrics open up new possibilities to charge energy storage devices when submitted to a temperature gradient.The charging voltage is internally from the ionic Seebeck effect of the electrolyte between two electrodes.Hence electrolytes with high thermoelectric figure of merit are classified as ionic thermoelectric materials.Most ionic thermoelectric materials are composed of abundant elements,and they can generate hundreds of times larger thermal voltage than that of electronic materials.This emerging thermoelectric category brings new hope to fabricate low cost and large area heat-to-energy conversion devices,and triggers a renewed interest for ionic thermodiffusion.In this review,we summarize the state of the art in the new field of ionic thermoelectrics,from the driving force of the ionic thermodiffusion to material and application developments.We present a general map of ionic thermoelectric materials,discuss the unique characters of each type of the reported electrolytes,and propose potential optimization and future topics of ionic thermoelectrics.

Ultralight Oxygen in Corundum-Bearing Rocks of North Karelia, Russia, as a Result of Isotope Separation by Thermal Diffusion (Soret Effect) in Endogenous Fluid Flow

Helium and argon isotopes in fluid inclusions in minerals of corundum bearing rocks with anomalous light oxygen of the Khitoostrov (North Karelia, Russia) were studied. It was found that atmospheric noble gas component is missing. Therefore, all previously proposed models of participation in the fluid surface ice meltwater are not valid. Proposed and justified endogenous mechanism of isotope fractionation of oxygen and other chemical elements by the mechanism of thermal diffusion. Geologically justified existence of the cascading effect for a number of the separation thermodiffusion cells, which lead to significant isotope effects. Cascading is realized due to the “fluid pump”, in which role are acting amphibolized gabbro in the contact with corundum metasomatites. It is assumed that the mechanism is not specific for the case corundum metasomatic rocks, which are a special case of manifestation of such a scenario in processes involving endogenous fluid flows.

Electric Field of the Ocean Induced by Diffusion

The equations for gradient of electric field in seawater induced by gradients of salinity, temperature and pressure were developed by means of non-equilibrium thermodynamics. Extrathermodynamic assumptions and accepted chemical model of seawater permit to carry out numerical calculations of electric field caused by diffusion, thermodiffusion and barodiffusion for realistic hydrophysical structure of the ocean. It is shown that contribution of barodiffusion into electric field of the ocean is almost constant (about -3 × 10-7 V/M). This magnitude can be ignored in many cases because it is too small. However natural salinity and temperature gradients significantly impact into electric field of the ocean.

Anionic entanglement-induced giant thermopower in ionic thermoelectric material Gelatin-CF_(3)SO_(3)K–CH_(3)SO_(3)K

Ionic thermoelectric(i-TE)technologies can power Internet of Things(IoT)sensors by harvesting thermal energy from the environment because of their large thermopowers.Present research focuses mostly on using the interactions between ions and matrices to enhance i-TE performance,but i-TE materials can benefit from utilizing different methods to control ion transport.Here,we introduced a new strategy that employs an ion entanglement effect.A giant thermopower of 28 mV K^(-1)was obtained in a quasi-solid-state i-TE Gelatin-CF_(3)SO_(3)K–CH_(3)SO_(3)K gel via entanglement between CF_(3)SO_(3)^(-)and CH_(3)SO_(3)^(-)anions.The anionic entanglement effect involves complex interactions between these two anions,slowing anionic thermodiffusion and thus suppressing bipolar effects and boosting p-type thermopower.A Au@Cu|Gelatin-CF_(3)SO_(3)K–CH_(3)SO_(3)K|Au@Cu i-TE device with a generator mode delivers a specific output energy density of 67.2 mJ m^(-2)K^(-2)during 2 h of discharging.Long-term operation.

Thermo-diffusion effects on MHD stagnation point flow towards a stretching sheet in a nanofuid

Thermodiffusion effects on stagnation point flow of a nanofuid towards a stretching surface with applied magnetic field is presented.Similarity transforms are applied to reduce the equations that govem the flow to a system of nonlinear ordinary differential equations.Runge-K utta-Fehlberg method is applied to solve the sy stem.Results are compared with existing solutions that are special cases to our problem.Concrete graphical analysis is carried out to study the effects of different emerging parameters such as stretching ratio A,mag netic infuence parameter M,Prandtl number Pr,Lewis number Le,Brownian motion parameter Nb,thermophoresis parameter Nr,nanofluid Lewis number Ln,modified Dufour parameter Nd and Dufour solutal number Ld coupled with comprehensive discussions.Numerical effects of local Nusselt number,local Sherwood number and nanofluid Sherwood number are also discussed.

Thermoelastic waves in a fractional-order initially stressed micropolar diffusive porous medium

The research article is the analysis of wave propagation in an initially stressed micropolar fractional-order derivative thermoelastic diffusion medium with voids.The governing equations in the context of generalized fractional-order derivative thermo-elasticity are formulated and the velocity equations are obtained.The plane wave solution of these equations indicates the existence of six plane waves,namely coupled longitudinal displacement(cL),coupled thermal(cT),coupled mass diffusion(cMD),coupled longitudinal void volume fraction(cV),coupled transverse displacement(cT D),and coupled transverse micro-rotational(cT M)waves.The sets of coupled waves(cL),(cT),(cMD)and(cV)are found to be dis-persive,attenuating and influenced by the presence of thermal,diffusion and voids parameters in the medium.The speeds of coupled transverse displacement(cT D),and coupled transverse micro-rotational(cT M)waves are not affected by thermal,diffusion and void parameters.The speeds of the plane waves,cL,cT,cMD,and cV are computed for a particular material and plotted against the thermal parameter,fre-quency,initial stress,diffusion and void parameters.

Thermoelastic diffusion problem for a half-space due to a refined dual-phase-lag Green-Naghdi model

The thermoelastic diffusion problem of an isotropic half-space is presented.The Green-Naghdi model with and without energy dissipation is proposed.Novel multi single/dual-phase-lag models are presented to investigate the thermoelastic diffusion behavior of the medium.The simple Green-Naghdi type Ⅱ and Ⅲ and their modified models are all examined here.The exact solution of thermodiffusion governing equations has been obtained considering the initial and boundary conditions.The validity of results is acceptable by comparing all variables.Benchmark results are reported to help other investigators in their future comparisons.

Transversal Instability for the Thermodiffusive Reaction-Diffusion System

The propagation of unstable interfaces is at the origin of remarkable patterns that are observed in various areas of science as chemical reactions, phase transitions, and growth of bacterial colonies. Since a scalar equation generates usually stable waves, the simplest mathematical description relies on two-by-two reaction-diffusion systems. The authors' interest is the extension of the Fisher/KPP equation to a two-species reaction which represents reactant concentration and temperature when used for flame propagation,and bacterial population and nutrient concentration when used in biology.The authors study circumstances in which instabilities can occur and in particular the effect of dimension. It is observed numerically that spherical waves can be unstable depending on the coefficients. A simpler mathematical framework is to study transversal instability, which means a one-dimensional wave propagating in two space dimensions.Then, explicit analytical formulas give explicitely the range of paramaters for instability.