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Search Results: 1 - 10 of 488753 matches for " F. M.; "
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Electrochemical Corrosion Behavior of Aluminum in Perchloric Acid  [PDF]
F. M. Mahgoub
Open Journal of Physical Chemistry (OJPC) , 2013, DOI: 10.4236/ojpc.2013.34022
Abstract:

The effects of acetate, citrate, benzoate, tetra-ethylammonium iodide (TEA) and 1,4,8,11 tetra-azacyclo-tetradecane (cyclam) on the corrosion behavior of aluminum in 1 M HClO4 at 40°C were studied by potentiodynamic polarization technique. Acetate, citrate, and benzoate inhibited the corrosion of aluminum and shifted the breakdown potential to positive direction. Cyclam was investigated as a macrocyclic organic inhibitor to the acid corrosion of aluminum. The addition of cyclam to the corroding medium showed a pronounced effect on the anodic but not on the cathodic part of the polarization curve. The addition of TEA to the medium enhanced the corrosion rate and shifted the breakdown potential to more negative value as the concentration increased. The results were discussed on the basis of the adsorption mechanism and the nature of the adsorbed species.

A Critical Analysis of Empiricism  [PDF]
F. M. Anayet Hossain
Open Journal of Philosophy (OJPP) , 2014, DOI: 10.4236/ojpp.2014.43030
Abstract: Empiricism is a philosophical theory which argues that human knowledge is derived entirely from sensory experience. As a branch of epistemology, empiricism disregards the concept of instinctive ideas and focuses entirely on experience and evidence as it relates to sensory perception. Empiricism is a philosophical school holding that knowledge can only be (or is primarily) gained from sensory experience. Accordingly, it rejects any (or much) use of a priori reasoning in the gathering and analysis of knowledge. It rivals rationalism according to which reason is the ultimate source of knowledge. The philosophy of empiricism was first put forth in John Locke’s An Essay Concerning Human Understanding. Locke argued that the only way by which human acquire knowledge is through experience. Locke firmly argued that humans are incapable of formulating or possessing inherent ideas. The aim of this paper is to explain that the traditional empiricist standpoint in the fields of epistemology and then try to show that it is not adequate for explaining some things relevant to these fields. For that the traditional empiricist methods needs to be supplemented by extra-logical principles that are not strictly empirical.
Valence Stabilization of Fe(II) Ions during Extended Gamma Irradiation of Their Aqueous Acidic Solutions Containing Phenol, Acetone, 4-Ethylpyridine or Hydrazine Hydrate  [PDF]
M. F. Barakat, M. M. Abdel Hamid
World Journal of Nuclear Science and Technology (WJNST) , 2015, DOI: 10.4236/wjnst.2015.52008
Abstract: Valence stabilization of polyvalent ions in acidic solutions during gamma irradiation is an important issue in nuclear aqueous chemical technology. Radiolysis and self irradiation problems encountered during chemical reprocessing of nuclear fuel or during chemical separation of transuranium elements or fission products are extremely important. Consequently studies on valence stabilization of polyvalent ions in strong gamma irradiation fields are very useful. In our previous publications, the valence stabilization of Fe(II) ions in acidic solutions during continuous gamma irradiation was achieved by using an inorganic compound; such as sodium sulfite, or some organic additives such as aliphatic alcohols, aldehyds or acids prior to irradiation. It was found that the efficiency of valence stabilization depends on the amount and chemical structure of the added compounds. In the present work, valence stabilization of divalent iron during gamma irradiation was studied in presence of some organic additives, belonging to some other classes of organic compounds such as Phenol (aromatic alcohol), Acetone (aliphatic ketone), 4-Aminopyridine (heterocyclic amino compound) and Hydrazine hydrate (aliphatic amino compound) to complement our previous studies. The results showed that valence stabilization of Fe(II) in presence of these compounds depends also on the amount and chemical structure of the additive used. Some interaction mechanisms have been proposed.
Valence Stabilization of Polyvalent Uranium Ions in Presence of Some Organic Additives during Extended Gamma Irradiation of Their Aqueous Acidic Solutions  [PDF]
M. F. Barakat, M. M. Abdelhamid
World Journal of Nuclear Science and Technology (WJNST) , 2015, DOI: 10.4236/wjnst.2015.53016
Abstract: In gamma irradiated aqueous acidic uranium solutions, tetravalent uranium ions are easily oxidized while U(VI) ions remain unchanged. In general, valence change of polyvalent metallic ions during chemical reprocessing of spent nuclear fuel solutions can lead to undesirable effects under the influence of the existing gamma radiations. Consequently, studies on valence stabilization of Uranium ions during chemical treatment in strong gamma irradiation fields seem to be highly interesting. It has been reported before that some organic compounds proved to be effective in stabilizing the valence of Fe(II) ions during extended gamma irradiation of their acidic solutions. In the present work, valence stabilization of Uranium ions in acidic solutions in presence of different classes of organic compounds has been studied. The results showed that in case of U(IV), methanol or formic acid are capable of providing about 80% protection while ethanol or acetaldehyde can provide about 70% protection. Propanol has the least protective effect i.e. about 54%. On using U(VI) instead of U(IV) in the irradiated solutions, the uranium ions were reduced and the formed U(IV) was protected as follows: formic acid or methanol can provide 69% or 63% protection respectively while ethanol, acetaldehyde or propanol can provide 50%, 35% and 24% respectively. In any case, protection exists as long as the organic additives were not completely consumed.
Fixed Point Theorems of Hegedus Contraction Mapping in Some Types of Distance Spaces  [PDF]
M. A. Ahmed, F. M. Zeyada, G. F. Hassan
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2012, DOI: 10.4236/ijmnta.2012.13013
Abstract: In the present paper, we prove some fixed point theorems of Hegedus contraction in some types of distance spaces, dislocated metric space, left dislocated metric space, right dislocated metric space and dislocated quasi-metric metric space which are generalized metrics spaces where self-distances are not necessarily zero.
Competency Improvement Needs of Farmers in Soil Erosion Prevention and Control for Enhancing Crop Production: Case Study of Kogi State, Nigeria  [PDF]
F. M. Onu, Abu Mohammed
Agricultural Sciences (AS) , 2014, DOI: 10.4236/as.2014.511103
Abstract: This study investigated the competency improvement needs of farmers in soil erosion prevention and control for enhancing crop production in Kogi state of Nigeria and was carried out between January and June, 2014. The study adopted descriptive survey research design and was guided by two research questions. The study found out that farmers needed improvement on 37 cultural practices as follows: 10 competencies in mulching, 12 in cover cropping, 8 in strip cropping, 7 in contour farming and 45 mechanical field practice as follows: 10 competencies in contour bonding, 11 in terracing, 12 in channeling and 11 in tunneling for success in soil erosion prevention and control. The study recommended the organization of rural based programmes for the training of farmers in the practice identified to enhance their competencies in soil erosion prevention and control for increased crop production.
Discovering Monthly Fuzzy Patterns  [PDF]
M. Shenify, F. A. Mazarbhuiya
International Journal of Intelligence Science (IJIS) , 2015, DOI: 10.4236/ijis.2015.51004
Abstract: Discovering patterns that are fuzzy in nature from temporal datasets is an interesting data mining problems. One of such patterns is monthly fuzzy pattern where the patterns exist in a certain fuzzy time interval of every month. It involves finding frequent sets and then association rules that holds in certain fuzzy time intervals, viz. beginning of every months or middle of every months, etc. In most of the earlier works, the fuzziness was user-specified. However, in some applications, users may not have enough prior knowledge about the datasets under consideration and may miss some fuzziness associated with the problem. It may be the case that the user is unable to specify the same due to limitation of natural language. In this article, we propose a method of finding patterns that holds in certain fuzzy time intervals of every month where fuzziness is generated by the method itself. The efficacy of the method is demonstrated with experimental results.
Localization of Voltage Regulators in Distribution Systems by a Mixed Genetic–Tabu Search Algorithm  [PDF]
M. C. Pimentel Filho, M. F. Medeiros
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B145
Abstract:

The optimal allocation of regulators banks in distribution systems is a merely combinatorial problem in which the best points of installation correspond to the best benefit, considering the admitted objective function, without violating and operating limits. The objective function must be chosen so that its value represents the operation state of the system. As the problem possesses combinatorial nature, its complexity will increase exponentially with the number of possibilities. Systems with large numbers of nodes and / or with the possibility of installing more than one bank require a large number of calculations to find the solution. An additional issue is the fact that the problem does not have a continuous nature, presenting discontinuity points in the objective function, limiting the application of optimization methods based on gradients. Based on the nature of the problem two optimization methods were used to solve the problem: Genetic Algorithm (GA) and modified Tabu Search (TS). The GA function will scour the search space and find regions with local minima that are candidates to be the solution. On the other hand the TS provides local search in the regions defined by GA so that the overall optimum is achieved.

Kroniek
- M.,- F.
Nieuwe West-Indische Gids , 1949,
Abstract:
Santos Basin Wind Patterns for Planning Offshore Pre-Salt Activities  [PDF]
Otto M. Machado Filho, Nelson F. F. Ebecken, Marilia M. F. de Oliveira
Journal of Environmental Protection (JEP) , 2015, DOI: 10.4236/jep.2015.610100
Abstract: Santos Basin contains the major hub of oil and gas exploration in Brazil. Consequently, knowledge of ocean surface winds in this area is very important for operational and planning activities. In addition, the importance of renewable energies is nowadays unquestionable, specifically in the case of the wind energy. In this paper, a data clustering technique is applied in order to obtain representative local wind patterns in Santos Basin. Reanalysis data from the National Centers for Environmental Prediction (NCEP) and National Center for Atmospheric Research (NCAR) have been used in this study.
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