scholarly journals An Electrochemical Study of Aluminum Corrosion in Boiling High Purity Water

CORROSION ◽  
1967 ◽  
Vol 23 (12) ◽  
pp. 365-370 ◽  
Author(s):  
R. A. LEGAULT ◽  
J. E. DRALEY
Keyword(s):  
Experimental Data ◽  
Protective Layer ◽  
Potential Drop ◽  
R And D ◽  
Total Potential ◽  
A Value ◽  
Wide Range ◽  
Aluminum Corrosion ◽  
Simplifying Assumptions

Abstract An equation relating current and electrochemical potential has been derived on the basis of a physical model of the corrosion process. In the model, the total potential drop from metal to solution is the sum of potential contributions arising from the interfacial reactions at the metal-oxide and oxide-solution interfaces and that which derives from the transport of charged species through the film. On the basis of some simplifying assumptions, the derived equation reduces to ΔE = IR + Ksℓn (1 + ID), where R and D are complex constants and Ks is equal to RT/αzF for the liberation of hydrogen at the surface of the protective layer. This equation has been fitted successfully to experimental data. Assigning the value usually attributed to α for the hydrogen reaction, 1/2, optimum values of the constants were found to vary reasonably with time. If a value of α is not assigned, the equation can be fitted to experimental data over a wide range of values for the three constants. Polarization measurements alone are not sufficient to determine unequivocal values for the constants, hence a determination of the mechanism of the aqueous oxidation of aluminum will require additional independent measurements.

scholarly journals Electro-osmotic flow enhancement in carbon nanotube membranes

2016 ◽  
Vol 374 (2060) ◽  
pp. 20150268 ◽  
Author(s):  
Davide Mattia ◽  
Hannah Leese ◽  
Francesco Calabrò
Keyword(s):  
Experimental Data ◽  
Carbon Nanotube ◽  
Osmotic Flow ◽  
Nanotube Membranes ◽  
Wide Range ◽  
Simplifying Assumptions ◽  
Carbon Nanotube Membranes ◽  
Simplified Solution ◽  
Electro Osmotic Flow

In this work, experimental evidence of the presence of electro-osmotic flow (EOF) in carbon nanotube membranes with diameters close to or in the region of electrical double layer overlap is presented for two different electrolytes for the first time. No EOF in this region should be present according to the simplified theoretical framework commonly used for EOF in micrometre-sized channels. The simplifying assumptions concern primarily the electrolyte charge density structure, based on the Poisson–Boltzmann (P-B) equation. Here, a numerical analysis of the solutions for the simplified case and for the nonlinear and the linearized P-B equations is compared with experimental data. Results show that the simplified solution produces a significant deviation from experimental data, whereas the linearized solution of the P-B equation can be adopted with little error compared with the full P-B case. This work opens the way to using electro-osmotic pumping in a wide range of applications, from membrane-based ultrafiltration and nanofiltration (as a more efficient alternative to mechanical pumping at the nanoscale) to further miniaturization of lab-on-a-chip devices at the nanoscale for in vivo implantation.

VLE Determination of Carbon Dioxide Loaded Aqueous Alkanolamine Mixtures Using Modified Kent Eisenberg Model

2017 ◽  
Vol 231 (11-12) ◽  
Author(s):  
Humbul Suleman ◽  
Abdulhalim Shah Maulud ◽  
Zakaria Man
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Model Parameters ◽  
Thermodynamic Models ◽  
Carbon Dioxide Absorption ◽  
Proposed Model ◽  
Wide Range ◽  
Experimental Values ◽  
Good Agreement

AbstractA computationally simple thermodynamic framework has been presented to correlate the vapour-liquid equilibria of carbon dioxide absorption in five representative types of alkanolamine mixtures. The proposed model is an extension of modified Kent Eisenberg model for the carbon dioxide loaded aqueous alkanolamine mixtures. The model parameters are regressed on a large experimental data pool of carbon dioxide solubility in aqueous alkanolamine mixtures. The model is applicable to a wide range of temperature (298–393 K), pressure (0.1–6000 kPa) and alkanolamine concentration (0.3–5 M). The correlated results are compared to the experimental values and found to be in good agreement with the average deviations ranging between 6% and 20%. The model results are comparable to other thermodynamic models.

scholarly journals Structure Determination of Ho2PdSi3

2014 ◽  
Vol 70 (a1) ◽  
pp. C224-C224
Author(s):  
Melanie Nentwich ◽  
Matthias Zschornak ◽  
Carsten Richter ◽  
Dmitri Novikov ◽  
Dirk Meyer
Keyword(s):  
Crystal Structure ◽  
Experimental Data ◽  
Local Environment ◽  
Ray Method ◽  
X Ray ◽  
Metal Silicides ◽  
Wide Range ◽  
Site Selective ◽  
Palladium Silicide

Holmium-Palladium-Silicide Ho2PdSi3 is a member of rare earth-transition metal silicides exhibiting a wide range of interesting magnetic and electrical properties like multiple transition temperatues. The crystal structure results from HoSi2 by substitution of Si by Pd which is ordering commensurably with a 2 × 2 × 8 superstructure confirmed by a previous XRD and a Diffraction Anomalous Fine Structure (DAFS) measurement of the super structure reflection 1/2 1/2 3/8. DAFS is a X-ray method combining the advantages of absorption and diffraction and hence offers the possibility of element and site selective studies. Thus, it was feasible to probe the local environment of Ho and Pd separately. In the following, we will present a comparison of several structure proposals of Ho2PdSi3 with experimental data from beamline E2 and BW1 of the former synchrotron DORIS III at DESY/HASYLAB.

scholarly journals An Improved Techno-Economic Approach to Determination of More Precise Installed Parameter for Small Hydropower Plants

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2419
Author(s):  
Vidosava Vilotijević ◽  
Uroš Karadžić ◽  
Radoje Vujadinović ◽  
Vuko Kovijanić ◽  
Ivan Božić
Keyword(s):  
Net Present Value ◽  
Design Flow ◽  
Hydropower Plant ◽  
Electricity Production ◽  
Small Hydropower ◽  
A Value ◽  
Hydropower Plants ◽  
Wide Range ◽  
Installed Capacity

Designing a small hydropower plant (SHPP) necessitates fulfillment of energy and ecological constraints, so a well-defined design flow is of the utmost significance. The main parameters of each SHPP are determined by appropriate techno-economic studies, whereas an improved approach to defining more precise SHPP installed parameter is presented in this paper. The SHPP installed parameter is the ratio of the design flow and averaged perennial flow obtained from the flow duration curve at the planned water intake location. Previous experiences in the design of SHPPs have shown that the SHPP installed parameter has a value in a wide range without the existence of an unambiguous equation for its determination. Therefore, with this aim, the thirty-eight (38) small watercources in the territory of Montenegro, denominated for the construction of SHPPs, have been investigated. SHPPs are divided into two groups depending on the installed capacity and the method of calculating the purchase price of electricity. For both groups, the range of SHPP installed parameter is determined according to the technical and economic criteria: the highest electricity production, the highest income, net present value (NPV), internal rate of return (IRR), and payback period (PB).

Analytical Determination of Viscous Permeability of Fibrous Porous Media

2008 ◽  
Author(s):  
A. Tamayol ◽  
M. Bahrami
Keyword(s):  
Experimental Data ◽  
Aspect Ratio ◽  
Unit Cell ◽  
Analytical Determination ◽  
Fibrous Media ◽  
Wide Range ◽  
Unit Cells ◽  
The Media ◽  
Micro Structures

In this study, the permeability of ordered fibrous media towards normal and parallel flow is determined analytically. In this approach, porous material is represented by a “unit cell” which is assumed to be repeated throughout the media. Several fiber arrangements including: touching and non-touching arrays are considered. Modeling 1D touching fibers as a combination of Channel-like conduits, a compact relationship is proposed to predict permeability. Employing an integral technique and assuming a parabolic velocity profile within the unit cells, analytical relationships are developed for pressure drop for rectangular arrangements. The developed models are successfully compared with existing experimental data collected by others for square arrangement over a wide range of porosity. Due to the random nature of the porous micro structures, determination of exact permeability of real fibrous media is impossible. However, the analyses developed for ordered unit cells enable one to predict the trends observed in experimental data. Moreover, it is shown that the proposed normal flow permeability of square unit cell serves as a lower bound for the permeability of fibrous media. The effects of unit cell aspect ratio and fibers diameter on the permeability are also investigated. It is noted that with an increase in the aspect ratio the normal permeability decreases while, the parallel permeability remains constant. It is also shown that the permeability of fibrous media is related to the diameter of fibers squared.

scholarly journals Improved information on astrophysical S-factor for the 10B(p,α0)7Be reaction using the Trojan Horse method

2018 ◽  
Vol 184 ◽  
pp. 02002
Author(s):  
A. Cvetinović ◽  
C. Spitaleri ◽  
R. Spartá ◽  
G.G. Rapisarda ◽  
S.M.R. Puglia ◽  
...  
Keyword(s):  
Experimental Data ◽  
Energy Range ◽  
Trojan Horse ◽  
Wide Energy Range ◽  
A Value ◽  
Bare Nucleus ◽  
Trojan Horse Method ◽  
S Factor ◽  
Wide Energy

The 10B(p,α0)7Be reaction has been studied by applying the Trojan Horse method to the 2H(10B,α0 7Be)n reaction. The bare-nucleus astrophysical S(E)-factor in absolute units was extracted in a wide energy range, from 2.2 MeV to 3 keV and normalized to the direct experimental data, thus allowing determination of the electron screening potential for which a value of Ue=391±74 eV was obtained.

Vitamin A Value of Plant Food Provitamin A - Evaluated by the Stable Isotope Technologies

2014 ◽  
Vol 84 (Supplement 1) ◽  
pp. 25-29 ◽  
Author(s):  
Guangwen Tang
Keyword(s):  
Stable Isotope ◽  
Vitamin A ◽  
Provitamin A ◽  
Animal Origin ◽  
Plant Food ◽  
Plant Foods ◽  
A Value ◽  
Provitamin A Carotenoids ◽  
Β Carotene

Humans need vitamin A and obtain essential vitamin A by conversion of plant foods rich in provitamin A and/or absorption of preformed vitamin A from foods of animal origin. The determination of the vitamin A value of plant foods rich in provitamin A is important but has challenges. The aim of this paper is to review the progress over last 80 years following the discovery on the conversion of β-carotene to vitamin A and the various techniques including stable isotope technologies that have been developed to determine vitamin A values of plant provitamin A (mainly β-carotene). These include applications from using radioactive β-carotene and vitamin A, depletion-repletion with vitamin A and β-carotene, and measuring postprandial chylomicron fractions after feeding a β-carotene rich diet, to using stable isotopes as tracers to follow the absorption and conversion of plant food provitamin A carotenoids (mainly β-carotene) in humans. These approaches have greatly promoted our understanding of the absorption and conversion of β-carotene to vitamin A. Stable isotope labeled plant foods are useful for determining the overall bioavailability of provitamin A carotenoids from specific foods. Locally obtained plant foods can provide vitamin A and prevent deficiency of vitamin A, a remaining worldwide concern.

LIQUIDUS THERMO-BAROMETER FOR THE MODELING OF MAGNETITE — MELT EQUILIBRIUM

2018 ◽  
pp. 71-80
Author(s):  
N. S. Aryaeva ◽  
E. V. Koptev-Dvornikov ◽  
D. A. Bychkov
Keyword(s):  
Experimental Data ◽  
Liquidus Temperature ◽  
Vertical Structure ◽  
Maximum Error ◽  
Silicate Melt ◽  
System Of Equations ◽  
Wide Range ◽  
Basaltic Melts ◽  
Multidimensional Statistics

A system of equations of thermobarometer for magnetite-silicate melt equilibrium was obtained by method of multidimensional statistics of 93 experimental data of a magnetite solubility in basaltic melts. Equations reproduce experimental data in a wide range of basalt compositions, temperatures and pressures with small errors. Verification of thermobarometers showed the maximum error in liquidus temperature reproducing does not exceed ±7 °C. The level of cumulative magnetite appearance in the vertical structure of Tsypringa, Kivakka, Burakovsky intrusions predicted with errors from ±10 to ±50 m.

DINAMIKA POLITIK PERSETUJUAN BERSAMA TENTANG PENETAPAN DESA ADAT DI KABUPATEN ROKAN HULU TAHUN 2014

2017 ◽  
Vol 15 (1) ◽  
pp. 21
Author(s):  
Haryo Suganda ◽  
Raja Muhammad Amin
Keyword(s):  
Regulatory Region ◽  
Field Research ◽  
Analysis Techniques ◽  
Political Dynamics ◽  
Political Interests ◽  
Wide Range ◽  
Information Method ◽  
Qualitative Descriptive ◽  
The Village

This study is motivated the identification of policies issued by the regional Governmentof Rokan Hulu in the form of Regulatory region number 1 by 2015 on the determination of thevillage and Indigenous Village. Political dynamics based on various interests against themanufacture of, and decision-making in the process of formation of the corresponding localregulations determination of Indigenous Villages in the Rokan Hulu is impacted to a verysignificantamount of changes from the initial draft of the number i.e. 21 (twenty one) the villagebecame Customary 89 (eighty-nine) the Indigenous Villages who have passed. Type of thisresearch is a qualitative descriptive data analysis techniques. The research aims to describe theState of the real situation in a systematic and accurate fact analysis unit or related research, aswell as observations of the field based on the data (information). Method of data collectionwas done with interviews, documentation, and observations through fieldwork (field research).The results of the research on the process of discussion of the draft local regulations andmutual agreement about Designation of Indigenous Villages in the Rokan Hulu is, showed thatthe political dynamics that occur due to the presence of various political interests, rejectionorally by Villagers who were judged to have met the requirements of Draft Regulations to beformulated and the area for the set to be Indigenous Villages, and also there is a desire fromsome villages in the yet to Draft local regulations in order to set the Indigenous village , there isa wide range of interests of these aspects influenced the agreement to assign the entire localVillage which is in the Rokan Hulu become Indigenous village, and the village of Transmigrationinto administrative Villages where the initiator of the changes in the number of IndigenousVillages in the Rokan Hulu it is the desire of the local Government of its own.

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