scholarly journals Volumetric hydraulic generator on a vehicle with rotational rate stabilization

2019 ◽  
Vol 42 (4) ◽  
pp. 36-41
Author(s):  
A.V. Lepeshkin ◽  
◽  
A.S. Medvedev ◽  
A.A. Mihajlin ◽  
◽  
...  
Keyword(s):  
Rotational Rate ◽  
Hydraulic Generator

scholarly journals Electrochemical removal of pyrite scale using green formulations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Musa Ahmed ◽  
Ibnelwaleed A. Hussein ◽  
Abdulmujeeb T. Onawole ◽  
Mohammed A. Saad ◽  
Mazen Khaled
Keyword(s):  
Hydrogen Sulfide ◽  
Current Density ◽  
Iron Sulfide ◽  
Chelating Agent ◽  
Electrical Current ◽  
Electrochemical Process ◽  
Chemical Dissolution ◽  
Hydrocarbon Production ◽  
Rotational Rate ◽  
Diethylenetriamine Pentaacetic Acid

AbstractPyrite scale formation is a critical problem in the hydrocarbon production industry; it affects the flow of hydrocarbon within the reservoir and the surface facilities. Treatments with inorganic acids, such as HCl, results in generation toxic hydrogen sulfide, high corrosion rates, and low dissolving power. In this work, the dissolution of pyrite scale is enhanced by the introduction of electrical current to aid the chemical dissolution. The electrolytes used in this study are chemical formulations mainly composed of diethylenetriamine-pentaacetic acid–potassium (DTPAK5) with potassium carbonate; diethylenetriamine pentaacetic acid sodium-based (DTPANa5), and l-glutamic acid-N, N-diacetic acid (GLDA). DTPA and GLDA have shown some ability to dissolve iron sulfide without generating hydrogen sulfide. The effect of these chemical formulations, disc rotational rate and current density on the electro-assisted dissolution of pyrite are investigated using Galvanostatic experiments at room temperature. The total iron dissolved of pyrite using the electrochemical process is more than 400 times higher than the chemical dissolution using the same chelating agent-based formulation and under the same conditions. The dissolution rate increased by 12-folds with the increase of current density from 5 to 50 mA/cm2. Acid and neutral formulations had better dissolution capacities than basic ones. In addition, doubling the rotational rate did not yield a significant increase in electro-assisted pyrite scale dissolution. XPS analysis confirmed the electrochemical dissolution is mainly due to oxidation of Fe2+ on pyrite surface lattice to Fe3+. The results obtained in this study suggest that electro-assisted dissolution is a promising technique for scale removal.

scholarly journals Influence of Rotation on the Stellar Parameters

1993 ◽  
Vol 137 ◽  
pp. 162-164 ◽  
Author(s):  
V. Wenske ◽  
D. Schönberner
Keyword(s):  
Lower Surface ◽  
Equatorial Region ◽  
Star Formation History ◽  
Rotational Rate ◽  
Visible Part ◽  
Photometric Observations ◽  
Formation History ◽  
Inclination Angles ◽  
Stellar Models ◽  
Stellar Masses

For several years it has become quite common to derive stellar parameters like effective temperature, Teff, and surface acceleration, g, by means of properly calibrated photometric indices, and to use these values for the derivation of important properties of stellar aggregates (viz. ages, star formation history, distances, etc.). Photometric observations, however, fail to give informations about one important property of a star: its rotational rate!The main effect of rotation is to increase the size of the star, mainly in the equatorial region, leading to lower surface temperatures and accelerations. Since in non–spherical stars Teff and g depend on the latitude, the observed values, which are, of course, averages over the visible hemisphere, depend on the angle of inclination, i. Collins & Sonneborn (1977) utilized the rigidly rotating stellar models of Sackmann and Anand (1970) to compute emergent fluxes and photometric indices for various stellar masses, inclination angles i and rotational parameters being the break–up rotational rate. These indices, viz. C0 and β, represent then averages over the visible part of the rotally distorted stellar models. Closer inspections indicated also that emergent fluxes and line profiles of rotationally distorted stars can be matched by the predictations of standard model atmospheres to a very high accuray, even for w close to unity (Wenske 1992, Diplom Thesis).

scholarly journals Rotationally inelastic dynamics of LiH (X1Σ+, v = 0) in collisions with Ar: State-to-state inelastic rotational rate coefficients

SpringerPlus ◽  
2014 ◽  
Vol 3 (1) ◽  
Author(s):  
Aliou Niane ◽  
Cheikh Amadou Bamba Dath ◽  
Ndèye Arame Boye Faye ◽  
Kamel Hammami ◽  
Nejm-Eddine Jaidane
Keyword(s):  
Rate Coefficients ◽  
Rotational Rate ◽  
Inelastic Dynamics

scholarly journals Investigation of acoustic fields in the arctic zone with uneven ice cover

2021 ◽  
Vol 254 ◽  
pp. 02007
Author(s):  
Vladimir Korochentsev ◽  
Сhen Wenjian ◽  
Victor Petrosyants ◽  
Tatiana Lobova ◽  
Julia Shpak
Keyword(s):  
Wave Propagation ◽  
Acoustic Waves ◽  
Signal Propagation ◽  
Ice Cover ◽  
Measuring System ◽  
The Arctic ◽  
Water Medium ◽  
Water Ice ◽  
Ice Surface ◽  
Hydraulic Generator

A mathematical model for elastic wave propagation in an ice cover with uneven relief (hummock) has been developed. The theoretical model is based on the application of “directed” Green’s functions. We obtained numerical results for different distances between radiating and receiving antennas installed inside the ice layer and in water medium. An information-measuring system was created to investigate elastic acoustic waves along ice surface based on electo-hydraulic generator. Experiments of high-frequency acoustic signal propagation from electro-hydraulic generator in water-ice-air system were carried out. We illustrated the model validity for the investigation of hydroacoustic wave propagation in real ice conditions.

New De-excitation Method for Large Hydraulic Generator

2011 ◽  
Vol 1 (2) ◽  
pp. 234-240
Author(s):  
Xianming Chen ◽  
Wei Wang ◽  
Hongshui Lu ◽  
Guohua Liu ◽  
Xiaodong Zhu
Keyword(s):  
Hydraulic Generator ◽  
Excitation Method

High Rotational-Rate Rotor With High-Temperature Superconducting Bearings

2009 ◽  
Vol 19 (3) ◽  
pp. 2078-2082 ◽  
Author(s):  
J.R. Hull ◽  
M. Strasik ◽  
J.A. Mittleider ◽  
J.F. Gonder ◽  
P.E. Johnson ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Superconducting ◽  
Rotational Rate

Rapid Synthesis of Nanostructural Intermetallics and their Bulk Properties

1996 ◽  
Vol 457 ◽  
Author(s):  
S. M. Pickard ◽  
A. K. Ghosh
Keyword(s):  
Grain Size ◽  
Physical Vapor Deposition ◽  
High Speed ◽  
Single Phase ◽  
Deposition Process ◽  
Indentation Hardness ◽  
Rotational Rate ◽  
Fine Grain ◽  
Compositional Variability ◽  
Nano Grains

ABSTRACTA rapid physical vapor deposition process (PVD) utilizing a high speed rotating substrate and small substrate-to-source spacing has been used to produce bulk sheet of Ti-Al alloys in the compositional range Ti-12% Al to Ti-75% Al1 at a rate of 1–3 μm/minute. Microstructural architectures produced by the method comprise of either fully homogenous phase mixtures of nano-grains, or nanolaminated material, depending on the substrate rotational rate, with lower rotational rate producing a layered microstructure. Defect populations within the as-deposited material are characterized by TEM and SEM, and hot pressing consolidation of the as-deposited material, which retains a grain size < 1000 nm, has been investigated. While indentation hardness of α2+γ(2 phase) alloys exceeded 7 GPa, brittle failure occurred in the elastic regime at nominally lower tensile stress than that for conventionally produced alloys containing Nb and Cr as solute elements. α2+γ alloys can exhibit tensile elongations of more than 100% at 850°C with retention of fine grain size. Elevated temperature failure occurs by the formation of voids in regions of compositional variability in the composite where single phase α2-Ti3Al structure was present.

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