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Search Results: 1 - 10 of 276096 matches for " V. E. Ebiekpe "
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Inhibitory Action of Artemisia annua Extracts and Artemisinin on the Corrosion of Mild Steel in H2SO4 Solution
P. C. Okafor,V. E. Ebiekpe,C. F. Azike,G. E. Egbung,E. A. Brisibe,E. E. Ebenso
International Journal of Corrosion , 2012, DOI: 10.1155/2012/768729
Abstract: The action of ethanol (EEAA), acid (AEAA), and toluene (TEAA) extracts from Artemisia annua and Artemisinin (ATS) on mild steel corrosion in H2SO4 solutions was investigated using gravimetric and gasometric techniques. The extracts and ATS functioned as good inhibitors, and their inhibition efficiencies (%IE) followed the trend: EEAA > AEAA > TEAA > ATS. %IE increased with increase in inhibitors concentration and decreased with increase in temperature. The enhanced %IE values of the extracts were attributed to synergistic effect of the components of the plant extracts with ATS. The adsorption of the inhibitors was consistent with Langmuir isotherm. Physisorption is proposed as the mechanism of inhibition. 1. Introduction Present trend in research on environmental friendly corrosion inhibitors is taking us back to exploring the use of natural products as possible sources of cheap, nontoxic, and ecofriendly corrosion inhibitors. These natural products are either synthesized or extracted from aromatic herbs, spices, and medicinal plants. Of increasing interest is the use of medicinal plant extracts as corrosion inhibitors for metals in acid solutions. This is because these plants serve as incredibly rich sources of naturally synthesized chemical compounds that are environmentally acceptable, inexpensive, readily available, and renewable sources of materials [1, 2]. These chemicals include alkaloids, flavonoids, terpenoids, glycosides, tannins, saponins, fats and oils, and carbohydrates, and so forth [3–11]. The complex composition of phytochemicals in plant extracts makes it difficult to attempt to assign the inhibition ability to a particular constituent. Some researchers have, however, ascribed the inhibition efficiency of these medicinal plants to their active components used for medical purposes [3]. We have recently attempted to assign the inhibition ability to some constituents by studying the inhibitive effect of different parts of a given plant with variable concentrations of the phytochemicals on acid corrosion [4–7]. Another most probable method would be the use of different solvents in the extraction process and comparing their inhibition efficiencies. This is yet to be explored in most of the reported work on corrosion inhibition of plant extracts. Artemisia annua is native to Asia, most probably China, but is currently cultivated in many countries including Nigeria, mainly as a source of artemisinin, an important natural sesquiterpene lactone with antimalarial effect against susceptible and multidrug resistant Plasmodium spp. The plant is a
Methane Formation by the Reaction of Coalbed Carbon with Water  [PDF]
V. E. Vigdergauz
Geomaterials (GM) , 2011, DOI: 10.4236/gm.2011.11003
Abstract: There is proposed a mechanism of methane and carbon dioxide formation by the direct reaction of carbon with water during catastrophic events in the mining of coal deposits. Thermodynamics of the reaction is dis-cussed.
The Conservation of Energy Space-Time Metric for Space Outside Matter  [PDF]
V. N. E. Robinson
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.48149

By using experimentally determined measurements of potential energy together with the principle of conservation of energy and solving directly, the space-time geometry equation for space outside matter is obtained. That equation fits all the experimental observations that support the accepted Schwarzschild metric, yet predicts there isn’t a singularity at the Schwarzschild radius. The accepted Schwarzschild metric is the first approximation of the conservation of energy space-time metric. No observation yet made can distinguish between the predictions of the two metrics.

The Energy Conservation Paradox of Quantum Physics  [PDF]
V. E. Shapiro
Journal of Modern Physics (JMP) , 2015, DOI: 10.4236/jmp.2015.611160
Abstract: This work asserts that quantum theory runs into a fundamental conflict with the principles of energy conservation inferred from the statistical evolution of interacting systems. The gist is the energy of systems by the principles of Lagrangian mechanics leaves out of account their energy associated with the phase flows of non-invariant phase volume. The quantum theory takes this fact into account, but does that improperly. We show it by presenting insoluble inconsistencies and a case study.
New Method of Thermal Energy—To Electrical Energy Conversion in Vacuum Devices with the Metal—Dielectric Nanofilm Electron Sources  [PDF]
V. E. Ptitsin
Materials Sciences and Applications (MSA) , 2018, DOI: 10.4236/msa.2018.913078
Abstract: New method of thermal energy—to electrical energy conversion in vacuum devices with the metal (W)—dielectric nanofilm (ZrO2) electron source is offered and studied. According to estimates and results of modeling, the energy effectiveness (χ) of the proposed method may exceed χ for the known thermionic energy conversion method to 2 - 3 orders of magnitude.
Peak Power Effect on Skin Rejuvenation Using IPL: Lumecca IPL Evaluation  [PDF]
E. V. Ross, Michael Kreindel
Advances in Aging Research (AAR) , 2016, DOI: 10.4236/aar.2016.53008
Abstract: A high peak power IPL system (Lumecca) was tested to determine the correlation between a high peak power and the successful treatment of pigmented and vascular lesions. Short pulse duration in the millisecond range and high peak power of 3.3 kW/cm2 enabled selective and effective destruction, not only of pigment, but also of vessels in a comparable manner to a pulsed dye laser. Only one treatment session at a low fluence (8 - 16 J/cm2) was sufficient to achieve the desired results.
Phonon Mediated Electron-Electron Scattering in Metals  [PDF]
V. Palenskis, E. ?itkevi?ius
World Journal of Condensed Matter Physics (WJCMP) , 2018, DOI: 10.4236/wjcmp.2018.83008
Abstract: It is shown that the linear resistivity dependence on temperature for metals above the Debye’s temperature mainly is caused by electron-electron scattering of randomly moving electrons. The electron mean free path in metals at this temperature range is in inverse proportion to the effective density of randomly moving electrons, i.e. it is in inverse proportion both to the temperature, and to the density-of-states at the Fermi surface. The general relationships for estimation of the average diffusion coefficient, the average velocity, mean free length and average relaxation time of randomly moving electrons at the Fermi surface at temperatures above the Debye’s temperature are presented. The effective electron scattering cross-sections for different metals also are estimated. The calculation results of resistivity dependence on temperature in the range of temperature from 1 K to 900 K for Au, Cu, Mo, and Al also are presented and compared with the experimental data. Additionally in temperature range from 1 K to 900 K for copper, the temperature dependences of the mean free path, average diffusion coefficient, average drift mobility, average Hall mobility, average relaxation time of randomly moving electrons, and their resultant phonon mediated scattering cross-section are presented.
Analysis of Rainfall Variability Using Remote Sensing and GIS in North Central Nigeria  [PDF]
O. Ideki, V. E. Weli
Atmospheric and Climate Sciences (ACS) , 2019, DOI: 10.4236/acs.2019.92013
Abstract: The importance of rainfall variability in successfully understanding the dynamics of climate change in any region cannot be overemphasized. This study examines rainfall variability in the North Central region including the Federal Capital Territory Abuja using remote sensing and geographic information system (GIS) application. The study employed satellite data basically from near real time data of Moderate Resolution Imaging Spectroradiometer (MODIS). Thereafter, the point data of rainfall was clipped to the shape file of Nigeria Boundary and interpolation using Inverse Distance Weight (IDW) was done to generate rainfall spatial maps from 2000-2017. The result reveal high temporal variation in rainfall particularly Niger, Plateau, Benue and Nassarawa states. The study therefore recommends close monitoring of periodic pattern of rainfall characteristics in the region by the Nigerian meteorological agency and to encourage farmers into drought tolerant and irrigation farming.
Numerical Modelling of Coal Combustion Processes in the Vortex Furnace with Dual-Port Loading  [PDF]
I. S. Anufriev, E. P. Kopyev, D. V. Krasinsky, V. V. Salomatov, E. Y. Shadrin, O. V. Sharypov
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B060
Abstract: The work is devoted to numerical simulation of pulverized-coal combustion processes in the vortex furnace which is a prospective design of a boiler unit for thermal power plants. New modification of this design characterized by additional tangential-injection nozzle located at the bottom of combustion chamber has been studied. Numerical results for the case of Siberian brown coal combustion in this vortex furnace with dual-port loading are presented, including 3-D aerodynamic structure, the fields of temperatures, radiated heat fluxes, species and dispersed phase concentrations, and NOx emissions.
Development of 3-D Gravity-Magnetic Models of the Earth’s Crust of Azerbaijan and Adjacent Areas: an Overview  [PDF]
Lev V. Eppelbaum, Boris E. Khesin
Positioning (POS) , 2011, DOI: 10.4236/pos.2011.22009
Abstract: Azerbaijan is located in the Alpine Himalayan collisional zone and is characterized by its complex and variable geological structure. To study Azerbaijan’s deep structure, twelve main regional interpreting profiles were selected for comprehensive 3D combined gravity-magnetic modeling. The development of the initial physical-geological models (PGMs) was based on known surface geology, drilling data, previous seismic, magnetotelluric and thermal data analysis, examination of the richest petrophysical data, as well as quantitative and qualitative gravity/magnetic data examination. The PGMs thus reflect the key structural-formational specifics of Azerbaijan’s geological structure, beginning from the subsurface (hundreds of meters) up to the Moho discontinuity (40 - 60 km). The PGMs revealed common factors controlling ore- and hydrocarbon bearing formations, primarily the boundaries of tectonic blocks, masked faults, and buried uplifts of magmatic rocks. Many of these factors can be used to investigate long-term geodynamic activity at a depth. The article summarizes many years of investigation by exemplifying the most typical PGMs for the Greater and Lesser Caucasus, the Kura depression, and central and northern Azerbaijan.
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