scholarly journals Energy conversion via metal nanolayers

2019 ◽  
Vol 116 (33) ◽  
pp. 16210-16215 ◽  
Author(s):  
Mavis D. Boamah ◽  
Emilie H. Lozier ◽  
Jeongmin Kim ◽  
Paul E. Ohno ◽  
Catherine E. Walker ◽  
...  
Keyword(s):  
Salinity Gradient ◽  
Electrical Current ◽  
Open Circuit ◽  
Single Step ◽  
Single Element ◽  
Liquid Droplets ◽  
Experimental Conditions ◽  
Flowing Liquid ◽  
Salinity Gradients ◽  
Thermal Oxide

Current approaches for electric power generation from nanoscale conducting or semiconducting layers in contact with moving aqueous droplets are promising as they show efficiencies of around 30%, yet even the most successful ones pose challenges regarding fabrication and scaling. Here, we report stable, all-inorganic single-element structures synthesized in a single step that generate electrical current when alternating salinity gradients flow along its surface in a liquid flow cell. Nanolayers of iron, vanadium, or nickel, 10 to 30 nm thin, produce open-circuit potentials of several tens of millivolt and current densities of several microA cm−2 at aqueous flow velocities of just a few cm s−1. The principle of operation is strongly sensitive to charge-carrier motion in the thermal oxide nanooverlayer that forms spontaneously in air and then self-terminates. Indeed, experiments suggest a role for intraoxide electron transfer for Fe, V, and Ni nanolayers, as their thermal oxides contain several metal-oxidation states, whereas controls using Al or Cr nanolayers, which self-terminate with oxides that are redox inactive under the experimental conditions, exhibit dramatically diminished performance. The nanolayers are shown to generate electrical current in various modes of application with moving liquids, including sliding liquid droplets, salinity gradients in a flowing liquid, and in the oscillatory motion of a liquid without a salinity gradient.

Structure and Resistance to Electrochemical Corrosion of NiTi Alloy

2013 ◽  
Vol 203-204 ◽  
pp. 335-338 ◽  
Author(s):  
Bożena Łosiewicz ◽  
Magdalena Popczyk ◽  
Tomasz Goryczka ◽  
Józef Lelątko ◽  
Agnieszka Smołka ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Niti Alloy ◽  
Electrochemical Corrosion ◽  
High Resolution Electron Microscopy ◽  
Potential Method ◽  
Passive Layer ◽  
Open Circuit ◽  
Experimental Conditions ◽  
Electrochemical Tests ◽  
Reflectivity Method

The NiTi alloy (50.6 at.% Ni) passivated for 30 min at 130°C by autoclaving has been studied towards corrosion resistance in aqueous solutions of 3% NaCl, 0.1 M H2SO4, 1 M H2SO4 and HBSS. Structure and thickness of the passive layer (TiO2, rutile) were examined by X-ray reflectivity method and high resolution electron microscopy. Corrosion behavior of this oxide layer was investigated by open circuit potential method and polarization curves. It was found that the corrosion resistance of the passivated NiTi alloy is strongly dependent on the type of corrosive environment. The higher corrosion resistance of the tested samples was revealed in sulfate solutions as compared to chloride ones. The highest resistance to electrochemical corrosion of the NiTi alloy was observed in 0.1 M H2SO4 solution. Susceptibility to pitting corrosion of the tested samples was observed which increased with the concentration rise of chlorine anions in solution. Electrochemical tests for 316L stainless steel carried out under the same experimental conditions revealed a weaker corrosion resistance in all solutions as compared to the highly corrosion resistant NiTi alloy.

Study on Calorimetry of Excess Heat in a d/Pd Gas-Loading System

2021 ◽  
Vol 881 ◽  
pp. 51-56
Author(s):  
Xing Ye Wang ◽  
Bing Jun Shen ◽  
Li Hong Jin ◽  
Ling Yu Li ◽  
Jian Tian
Keyword(s):  
Heat Flow ◽  
Isothermal Calorimetry ◽  
Electrical Current ◽  
Input Power ◽  
Heat Power ◽  
Experimental Conditions ◽  
Excess Heat ◽  
Flow Calorimeter ◽  
Loading System ◽  
Deuterium Pressure

A heat-flow calorimeter was introduced into the D/Pd gas-loading system to confirm the reliability and accuracy of the results obtained by isothermal calorimetry in the previous work. The effects of input power (electrical current) and pressure on excess heat were discussed under different experimental conditions. The results showed that the heat-flow calorimetry had higher accuracy than isothermal calorimetry. Under deuterium pressure of 30 kPa, the excess heat power decreased with the decrease of the input power, and the maximum excess heat power was (6.40 ± 0.19) W with an input power of 380 W. In the experiments of discussing the relationship between pressure and excess heat, the results showed there was a maximum excess power of (10.28 ± 3.40) W when the deuterium pressure was 220 Pa. The excess heat measured in the system was far more than that in chemical reaction. The results of SEM and EDS implied that excess heat came from nuclear transmutation processes.

scholarly journals A Case Study of Enhanced Sulfidization Flotation of Lead Oxide Ore: Influence of Depressants

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 95
Author(s):  
Haiyun Xie ◽  
Rui Sun ◽  
Jizong Wu ◽  
Dongxia Feng ◽  
Likun Gao
Keyword(s):  
Lead Oxide ◽  
Open Circuit ◽  
Bench Test ◽  
Infrared Spectrometry ◽  
Experimental Conditions ◽  
Function Mechanism ◽  
Lead Metal ◽  
Special Value ◽  
Flotation Method

The refractory lead oxide ore has become an important source of lead metal with the continuous depletion of lead sulfide minerals. Lead oxide ore is of poor floatability and there are few cases to concentrate it successfully. In this study, the sulfidization-xanthate flotation method is applied for the beneficiation of lead oxide ore in Yunnan Province (China) with sodium hexametaphosphate and carboxymethyl cellulose as depressant. Chemical analysis and phase analysis was performed to explore the physicochemical property of raw ore, which provides a research basis for process design and operational control. The main influencing factors during the process, including grinding fineness, reagent types, and dosage, etc., have been studied through flotation tests. Zeta potential measurements and Fourier transfer-infrared spectrometry (FTIR) analysis were conducted to reveal the function mechanism of the reagents. Based on the determined experimental conditions, open circuit tests and closed circuit tests with one stage rougher, three-stage scavenger, and two-stage cleaner flotation, were carried out with the run-of-mine ore with a lead grade of 4.57%. Through close circuit bench test, the lead concentrate with a lead grade of 64.08% and recovery of 92.30% was obtained. This study is of special value, as it provides referencing significance for economically exploiting lead oxide ore.

scholarly journals Analysis of fish assemblages in sectors along a salinity gradient based on species, families and functional groups

2013 ◽  
Vol 61 (4) ◽  
pp. 251-264 ◽  
Author(s):  
Ana Carolina dos Passos ◽  
Riguel Feltrin Contente ◽  
Felippe Veneziani Abbatepaulo ◽  
Henry Louis Spach ◽  
Ciro Colodetti Vilar ◽  
...  
Keyword(s):  
Functional Groups ◽  
Fish Assemblages ◽  
Salinity Gradient ◽  
Fish Fauna ◽  
Abundant Species ◽  
Number Of Species ◽  
Salinity Gradients ◽  
Gradient Based ◽  
Subtropical Estuaries ◽  
East West

Here we test the effects of the east-west salinity gradient in the subtropical Paranaguá Bay Estuarine Complex (PEC) on the structure of shallow water fish fauna, determined according to taxonomic (families and species) and functional composition metrics. A total of 152 species were observed. The families with the largest number of species were the Sciaenidae, Carangidae, Haemulidae and Gobiidae. The most abundant species were Atherinella brasiliensis, Harengula clupeola, Anchoa januaria and Anchoa tricolor. Marine stragglers dominated in number of species, followed by marine migrants and estuarine species. Most species were zoobenthivores, followed by piscivores and zooplanktivores. Families and species more frequently associated with estuarine conditions dominated in the mesohaline sector, and those more frequently associated with marine conditions dominated in the euhaline sector. The fish assemblages along the estuarine salinity gradient were found to be better characterized by taxonomic metrics than by functional ones. This is most likely because individuals of all functional groups inhabit all salinity sectors, and thus these metrics are not useful for differentiating assemblages along salinity gradients. Our results differ from those of other studies in tropical and subtropical estuaries, which have emphasized the importance of functional groups in determining fish assemblages along salinity gradients.

Modeling and Experimental Validation of a Reed Check Valve for Hydraulic Applications

2016 ◽  
Author(s):  
Anthony L. Knutson ◽  
James D. Van de Ven
Keyword(s):  
Internal Combustion Engines ◽  
Check Valve ◽  
Maximum Error ◽  
Fast Response ◽  
Single Element ◽  
Hydraulic Systems ◽  
Test Bed ◽  
Experimental Conditions ◽  
Wide Range ◽  
Reed Valve

Reed valves are a type of check valve commonly found in a wide range of applications including air compressors, internal combustion engines, and even the human heart. While reed valves have been studied extensively in these applications, published research on the modeling and application of reed valves in hydraulic systems is severely lacking. Because the spring and mass components of a reed valve are contained in a single element, it is light and compact compared to traditional disc, poppet, or ball style check valves. These advantages make reed valves promising for use in high frequency applications such as piston pumps, switch-mode hydraulics, and digital hydraulics. Furthermore, the small size and fast response of reed valves provide an opportunity to design pumps capable of operating at higher speeds and with lower dead volumes, thus increasing efficiency and power density. In this paper, a modeling technique for reed valves is presented and validated in a hydraulic piston pump test bed. Excellent agreement between modeled and experimentally measured reed valve opening is demonstrated. Across the range of experimental conditions, the model predicts the pump delivery with an error typically less than 1% with a maximum error of 2.2%.

Numerical simulations of non-stationary distributions of electrochemical potentials in SOFC

2017 ◽  
Vol 34 (6) ◽  
pp. 1956-1988 ◽  
Author(s):  
Mayu Muramatsu ◽  
Keiji Yashiro ◽  
Tatsuya Kawada ◽  
Kenjiro Tarada
Keyword(s):  
Steady State ◽  
Numerical Simulations ◽  
Chemical Potential ◽  
Simulation Method ◽  
Open Circuit ◽  
Operating Conditions ◽  
Stationary Distributions ◽  
Experimental Conditions ◽  
Content Type ◽  
Numerical Examples

Purpose The purpose of this study is to develop a simulation method to calculate non-stationary distributions of the chemical potential of oxygen in a solid oxide fuel cell (SOFC) under operation. Design/methodology/approach The initial-boundary value problem was appropriately formulated and the appropriate boundary conditions were implemented so that the problem of non-stationary behavior of SOFC can be solved in accordance with actual operational and typical experimental conditions. The dependencies of the material properties on the temperature and partial pressure of oxygen were also elaborately introduced to realize actual material responses. The capability of the proposed simulation method was demonstrated under arbitrary operating conditions. Findings The steady state calculated with the open circuit voltage condition was conformable with the analytical solution. In addition, the transient states of the spatial distributions of potentials and currents under the voltage- and current-controlled conditions were successfully differentiated, even though they eventually became the same steady state. Furthermore, the effects of dense materials assumed for interconnects and current collectors were found to not be influential. It is thus safe to conclude that the proposed method enables us to simulate any type of transient simulations regardless of controlling conditions. Practical implications Although only uniaxial models were tested in the numerical examples in this paper, the proposed method is applicable for arbitrary shapes of SOFC cells. Originality/value The value of this paper is that adequate numerical simulations by the proposed method properly captured the electrochemical transient transport phenomena in SOFC under various operational conditions, and that the applicability was confirmed by some numerical examples.

scholarly journals Power Conversion and Its Efficiency in Thermoelectric Materials

Entropy ◽  
2020 ◽  
Vol 22 (8) ◽  
pp. 803 ◽  
Author(s):  
Armin Feldhoff
Keyword(s):  
Thermoelectric Material ◽  
Electric Charge ◽  
Power Factor ◽  
Short Circuit ◽  
Power Conversion ◽  
Electrical Power ◽  
Electrical Current ◽  
Open Circuit ◽  
Pump Mode ◽  
Current Curve

The basic principles of thermoelectrics rely on the coupling of entropy and electric charge. However, the long-standing dispute of energetics versus entropy has long paralysed the field. Herein, it is shown that treating entropy and electric charge in a symmetric manner enables a simple transport equation to be obtained and the power conversion and its efficiency to be deduced for a single thermoelectric material apart from a device. The material’s performance in both generator mode (thermo-electric) and entropy pump mode (electro-thermal) are discussed on a single voltage-electrical current curve, which is presented in a generalized manner by relating it to the electrically open-circuit voltage and the electrically closed-circuited electrical current. The electrical and thermal power in entropy pump mode are related to the maximum electrical power in generator mode, which depends on the material’s power factor. Particular working points on the material’s voltage-electrical current curve are deduced, namely, the electrical open circuit, electrical short circuit, maximum electrical power, maximum power conversion efficiency, and entropy conductivity inversion. Optimizing a thermoelectric material for different working points is discussed with respect to its figure-of-merit z T and power factor. The importance of the results to state-of-the-art and emerging materials is emphasized.

Photosynthesis-inspired bifunctional energy-harvesting devices that convert light and salinity gradients into electricity

2018 ◽  
Vol 54 (87) ◽  
pp. 12310-12313 ◽  
Author(s):  
Huihui Ren ◽  
Tianliang Xiao ◽  
Qianqian Zhang ◽  
Zhaoyue Liu
Keyword(s):  
Energy Harvesting ◽  
Salinity Gradient ◽  
Salinity Gradients ◽  
Energy Harvesting Devices

An energy-harvesting device that is capable of converting light and a salinity gradient into electricity simultaneously was demonstrated conceptually.

scholarly journals Thickness-modulated tungsten–carbon superconducting nanostructures grown by focused ion beam induced deposition for vortex pinning up to high magnetic fields

2016 ◽  
Vol 7 ◽  
pp. 1698-1708 ◽  
Author(s):  
Ismael García Serrano ◽  
Javier Sesé ◽  
Isabel Guillamón ◽  
Hermann Suderow ◽  
Sebastián Vieira ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Focused Ion Beam ◽  
Vortex Lattice ◽  
Ion Beam ◽  
Electrical Current ◽  
Single Step ◽  
Vortex Pinning ◽  
High Magnetic Fields ◽  
Pinning Potential ◽  
External Stimuli

We report efficient vortex pinning in thickness-modulated tungsten–carbon-based (W–C) nanostructures grown by focused ion beam induced deposition (FIBID). By using FIBID, W–C superconducting films have been created with thickness modulation properties exhibiting periodicity from 60 to 140 nm, leading to a strong pinning potential for the vortex lattice. This produces local minima in the resistivity up to high magnetic fields (2.2 T) in a broad temperature range due to commensurability effects between the pinning potential and the vortex lattice. The results show that the combination of single-step FIBID fabrication of superconducting nanostructures with built-in artificial pinning landscapes and the small intrinsic random pinning potential of this material produces strong periodic pinning potentials, maximizing the opportunities for the investigation of fundamental aspects in vortex science under changing external stimuli (e.g., temperature, magnetic field, electrical current).

Protocrystalline Si:H p-type Layers for Maximization of the Open Circuit Voltage in a-Si:H n-i-p Solar Cells

2002 ◽  
Vol 715 ◽  
Author(s):  
R. J. Koval ◽  
Chi Chen ◽  
G. M. Ferreira ◽  
A. S. Ferlauto ◽  
J. M. Pearce ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Gas Flow ◽  
Open Circuit Voltage ◽  
Film Growth ◽  
Chemical Vapor ◽  
Open Circuit ◽  
Single Step ◽  
Rf Plasma ◽  
Growth Regime

AbstractWe have revisited the issue of p-layer optimization for amorphous silicon (a-Si:H) solar cells, correlating spectroscopic ellipsometry (SE) measurements of the p-layer in the device configuration with light current-voltage (J-V) characteristics of the completed solar cell. Working with p-layer gas mixtures of H2/SiH4/BF3 in rf plasma-enhanced chemical vapor deposition (PECVD), we have found that the maximum open circuit voltage (Voc) for n-i-p solar cells is obtained using p-layers prepared with the maximum possible hydrogen-dilution gas-flow ratio R=[H2]/[SiH4], but without crossing the thickness-dependent transition from the a-Si:H growth regime into the mixed-phase amorphous + microcrystalline [(a+μc)-Si:H] regime for the ∼200 Å p-layers. As a result, optimum single-step p-layers are obtained under conditions similar to those applied for optimum i-layers, i.e., by operating in the so-called “protocrystalline” Si:H film growth regime. The remarkable dependence of the p-layer phase (amorphous vs. microcrystalline) and n-i-p solar cell Voc on the nature of the underlying i-layer surface also supports this conclusion.

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