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Search Results: 1 - 10 of 295166 matches for " O. P.; "
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Distribution and Association of Arbuscular Mycorrhizal Fungi in Different Cultivars of Wheat from Lalganj Pratapgarh District of Utter Pradesh, India  [PDF]
O. P. Dwivedi
Advances in Bioscience and Biotechnology (ABB) , 2015, DOI: 10.4236/abb.2015.65034
Abstract: Arbuscular mycorrhizal fungi are key components of soil micro-flora and obviously interact with other microorganisms in the rhizosphere which is the zone of influence of plant roots on microbial populations and other soil constituents. Keeping in view the importance of AM fungi, the present study was undertaken for assessing the AM fungal spore population dynamics in the rhizosphere soil and its colonization in rhizosphere soils in relation to soil physico-chemical factors. Present study represents an attempt to establish the qualitative and quantitative distribution of AM fungal species in rhizosphere soils of wheat. Thirteen different wheat cultivars collected from four different sites of Lalganj Pratapgarh (U.P.), India were examined for the AM infection. All the wheat cultivars were found to be infected with arbuscular mycorrhizae. However, their population in rhizosphere and root infection varied to a considerable extent from species to species. The maximum spore population and highest percentage of root colonization were found with the rhizosphere soil of cultivars Ankur Kedar.
Effect of Magnesium and Calcium as Spheroidizers on the Graphite Morphology in Ductile Cast Iron  [PDF]
O.O Oluwole, O.E. Olorunniwo, O.O. Ogundare, P.O. Atanda, O.O Oridota
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2007, DOI: 10.4236/jmmce.2007.61003
Abstract: This study investigated the effect of magnesium and calcium as spheroidizers on the graphite microstructure in cast iron. The cast iron samples were melted in an induction furnace with charge of known composition and, magnesium and calcium of known percentages were added as spheriodizers to the molten metal in the mould during the casting process. From the microstructure of the as- cast specimens it was observed that the use of 100% Mg and a combined addition of 60% and 40%Ca as spheriodizers produced graphite spheroids instead of graphite flakes in the cast iron microstructure. The use of 100% Ca addition resulted in the production of graphite flakes in the specimen microstructure. The use of 80% Mg and 20% Ca resulted in the production of a chunky, stubby graphite microstructure, while the additions of 50% Mg and 50% Ca, 40%Mg and 60% Ca, and 20% Mg and 80% Ca resulted in the microstructure having a flaky graphite microstructure.
Optimizing the Properties of Polyether Based Polyurethane Foam  [PDF]
F. O. Aramide, P. O. Atanda, E. O. Olorunniwo
Open Journal of Polymer Chemistry (OJPChem) , 2013, DOI: 10.4236/ojpchem.2013.34015

Effect of different chemicals and additives used in producing polyester foam was investigated. Reference samples were produced from polyol, toluene di isocyanate (TDI), amine stannous octoate distil water, and silicone oil using laboratory mix formulation based on 500 g polyether based polyol. Other samples were produced by consecutively varying the content of all the additives with the exception of polyol. Standard sample dimensions for density test, indentation test, compression set test, tensile strength and elongation tests were produced from the samples. The various tests were carried out on the samples using the ASTM-D3574 standards. It was observed that the degree of indentation affects the value of indentation hardness and increasing the percentage content of TDI results in acceptable compression set value for the polyester samples. It was concluded that Holding all other parameters constant, reducing the water content and increasing the TDI content will yield polyester foam of optimum properties.

Investigation of the Effect of the Addition of Petroleum Waste to Interlocking Bricks Constituent  [PDF]
P. O. Atanda, O. O. Oluwole, I. D. Olumor
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2011, DOI: 10.4236/jmmce.2011.104026
Abstract: Incinerator ash was investigated for its potential use as a replacement for sand and cement in concrete interlocking bricks. The physical characteristics of the raw materials were examined. Two sets of mixes were prepared. For the first set, sand and water quantities were fixed while incinerator ash was used at 0% to 100% replacement by weight for cement in steps of 10%. In the second set, incinerator ash was used at 0% to 100% replacement by weight for sand while cement and water quantities was fixed. The mixing proportions for cement, sand and water were 1:3:0.7, respectively. Compressive strength and leachability tests were performed on the specimens. Results showed that the replacement of sand by incinerator ash up to 40% exhibited higher compressive strength than the control mix (0% incinerator ash) after 28 days curing. Maximum compressive strength of 33.33N/mm2 was obtained after 28 days curing using using 20% incinerator ash substitution for sand. Replacement of cement by incinerator ash up to 20% exhibited higher compressive strength than the control mix. Compressive strength of 28.2 N/mm2 was achieved after 28 days curing period using a 20% ash substitution for cement. Leaching of heavy metals (Pb and Cd ) present in the ash was observed in concentrated nitric acid.
Simulation of Torque during Rod Rolling of HC SS316 at Low Strain Rate Using “Phantom-Roll” Method  [PDF]
P. O. Aiyedun, O. S. Igbudu, B.O. Bolaji
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2011, DOI: 10.4236/jmmce.2011.1015114
Abstract: Rolling torque for a seventeen passes, 125 x 125 mm HC SS316 billets rolled to a 16 mm diameter rod have been simulated. Torque calculations based on pressure exerted by the metal on the rolls and the area of contact during longitudinal rolling were obtained using the temperature values derived using the “Phantom Roll” method. Investigations were carried out for four different starting mean rolling temperatures between 988℃ and 1191℃ and at four different strain rates of 0.4s-1, 0.8s-1, 1.2 s-1 and 1.6s-1. Results obtained showed that for all cases, rolling in grooved rolls required higher torque compared to rolling in flat rolls. In general, it was observed that torque value increased as starting temperature decreases and for each set of starting temperatures, the torque value increases with temperature. In all cases, the torque values for grooved rolls were higher than those for flat rolls. This was due to the higher frictional effect, occasioned by the larger contact area between roll and stock. Results obtained also revealed an inverse relationship between strain rate and torque.
Theoretical Estimation of Stability of Dielectric Elastomers  [PDF]
Asha Dahiya, O. P. Thakur
World Journal of Condensed Matter Physics (WJCMP) , 2012, DOI: 10.4236/wjcmp.2012.24036
Abstract: When dielectric elastomers sandwiched between compliant electrodes and high electric voltage is applied to the dielectric elastomers. Then due to the electrostatic force between the electrodes the elastomers expands in plane and contract out of plane so that it becomes thinner. As the thickness decreases we observe the increase in the applied electric voltage with the positive feedback effect. This positive feedback leads the electrical as well as mechanical breakdown of elastomer. By applying a mechanical pre-stretch the mechanical stability of dielectric elastomers gets also increased. In this paper, a new generalized set of strain/stretch variables qrN has been introduced to get the expression for second order elastic moduli for the ideal electro elastic material deformed to orthorhombic structure. The strength of a loaded crystal determined from the new moduli has been compared with the strength of classical (Green, Stretch) moduli. It has been observed that the use of incorrect formula by ignoring shear strain leads to incorrect estimation of stability. This problem has been resolved by considering stretch variable in tensor form as generally observed in the process of electrostriction in the elastomers.
Structure and Curvatures of Trajectories of a 2D Log-Gas  [PDF]
M. P. Pato, O. Bohigas
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.25005
Abstract: A model is constructed to study the statistical properties of irregular trajectories of a log-gas whose positions are those of the complex eigenvalues of the unitary Ginibre ensemble. It is shown that statistically the trajectories form a structure that reveals the eigenvalue departure positions. It is also shown that the curvatures of the ensemble of trajectories are Cauchy distributed.
Design and Implementation of Remotely Controlled Vehicle Anti-Theft System via GSM Network  [PDF]
T. T. Oladimeji, P. O. Oshevire, O. O. Omitola, O. E. Adedokun
Wireless Sensor Network (WSN) , 2013, DOI: 10.4236/wsn.2013.58018

The purpose of this paper is to build a secured and reliable vehicle anti-theft system which will have the ability to access the vehicle subsystems from a remote location where there is GSM network. And also, the design method involves the interfacing of GSM/GPRS modem module with the vehicle ignition subsystem, and the test result shows that it performs some control actions on the vehicle subsystems from a mobile phone, having taken the advantage of the wide coverage area of some GSM networks. Hence the topic is “Remotely Controlled Vehicle Anti-theft System via GSM Network”.

Corrosion Behavior of 18/8 Stainless Steel and Nickel-Plated Low Carbon Steel in Cassava Fluid  [PDF]
O.O. Oluwole, P.O. Atanda, O.A. Odekunbi, E. Odegbaju
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2009, DOI: 10.4236/jmmce.2009.810069
Abstract: This research work investigated the corrosion resistance of nickel- plated medium carbon steel and 18/8 stainless steel in cassava fluid (i.e. containing hydrogen cyanide). It simulated the effect of continuous use of the materials in a cyanide environment where corrosion products are left in place. Low carbon steel sample was nickel electroplated at 4V for 35 minutes. The plated sample, the unplated and the 18/8 stainless steel were then subjected to a cassava fluid environment for thirty days. The electrode potentials, in mV (SCE), were measured every day. Weight loss was determined at intervals of 5 days for duration of the exposure period. The result showed little corrosion attack on the nickel-plated steel on the fifth and tenth days which quickly dropped to zero by the 15th day and remained at the passive state till the 20th day when corrosion picked up again increasing steadily, linearly until the end of the test day. Corrosion of the 18/8 stainless steel was very low as well decreasing till the last day of the test. The pH of the cassava solution which initially was acidic because of the cyanide content in the cassava was observed to progress to neutrality within five days and to alkalinity at the end of the thirty days test (because of corrosion product contamination of the cyanide). Un-plated steel was found to be unsuitable for the fabrication of cassava processing machinery because of the very high corrosion rate. 18/8 stainless steel was found suitable for use in this environment. The renewed corrosion activity on nickel plated steel after the 20th day (pH=12) of continuous use in cyanide environment makes it unsuitable for use.
Corrosion Characteristics of Ascast Ductile Iron in Lime Juice  [PDF]
F.O. Aramide, E.O. Olorunniwo, P.O. Atanda, J.O. Borode
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2010, DOI: 10.4236/jmmce.2010.910063
Abstract: A study on the corrosion characteristics of ascast ductile iron in lime juice was conducted using the common weight loss method. Five standard tensile samples were prepared from the ascast condition of the alloy. One of them was taken to be for control, while the others were labeled A, B, C, and D. These labeled samples were then immersed in freshly extracted lime juice for a period of four weeks, having noted their respective initial weights. A sample was withdrawn from the medium at the end of each week for microstructural and tensile properties (using INSTRON 1195 at a fixed crosshead speed of 10mm min-1) examination for comparison with those of the control sample. It was observed that the mechanical properties of the alloy were deteriorating due to pitting corrosion and that the corrosion rate increases with increase in the pH of the medium. It was concluded that corrosion rate can be kept to the minimum by controlling the pH of the media within the range 2.0 to 3.05.
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