Investigation Of The Suitability Of Polyphosphoric Acid In Reducing The Degree Of Thermal Aging Of Agabu Natural Bitumen

Bitumen otherwise known as asphalt is a complex mixture of hydrocarbons which are naturally occurring or obtained from crude oil distillation. Bitumen when used as a binder in road pavement deteriorates with time as result of traffic load and contact of the pavement with environmental factors. The degradation of bitumen causes a rapid aging of the asphalt based pavement leading to road problems such as rutting, potholes etc. This deterioration is attributed to oxidative degradation of molecules of bitumen by factors such as heat, moisture and sunlight. This study investigates the viability of using polyphosphoric acid (PPA) to reduce the oxidative degradation effect of heat (at 60oC) on constituents of Agbabu Natural Bitumen (ANB) with a view to making it more durable when used for road pavement. Modification of ANB with PPA was carried out at 160oC using melt blend technique. Thereafter, the PPA modified and neat ANB samples were thermally aged in a hot air oven at 60oC. Fourier Transform Infrared (FTIR) Spectroscopy was used to validate the changes in the structure of ANB and aging indexes of neat and PPA modified samples of ANB calculated. The result showed that aging indexes of PPA modified samples of ANB were lower compared with that of the neat or unmodified samples of ANB. This implies that the rate of aging (at 60oC) of the unmodified ANB was faster than that of PPA modified ANB. Thus, a good potential for reducing thermal aging in ANB was found in PPA

Hadron Production in Neutrino-Nucleon Interactions at High Energies

The multi-particle production at high energy neutrino- nucleon collisions are investigated through the analysis of the data of the experiment CERN-WA-025 at neutrino energy less than 260GeV and the experiments FNAL-616 and FNAL-701 at energy range 120-250 GeV. The general features of these experiments are used as base to build a hypothetical model that views the reaction by a Feynman diagram of two vertices. The first of which concerns the weak interaction between the neutrino and the quark constituents of the nucleon. At the second vertex, a strong color field is assumed to play the role of particle production, which depend on the momentum transferred from the first vertex. The wave function of the nucleon quarks are determined using the variation method and relevant boundary conditions are applied to calculate the deep inelastic cross sections of the virtual diagram.Comment: 6 pages PDF forma

ECONOMIC GROWTH AND INCOME INEQUALITY IN SUB-SAHARAN AFRICA

Economies of Sub-Saharan African (SSA) countries have been growing slowly in recent time. Economic growth is thought to affect inequality but not much is known about the nature of such relationship in SSA and there is no concordance among the few available. This paper examined the relationship between economic growth and inequality in the region using data from 1990 to 2017estimated with the Panel Autoregressive Distributed Lag (ARDL) Model and Granger Causality. Hausman’s test suggested the superiority of the Pooled Mean Group (PMG) over the Mean Group (MG) Model. The PMG results showed that economic growth had significant and negative effect on income inequality (proxy by GINI-coefficient) in the long run suggesting a state of the later part of the Kuznet curve. This is in addition to the negative effect in the short run which is contrary to the theory. Furthermore, the result of the Granger Causality test revealed evidence of unidirectional relationship running from economic growth to income inequality in the region. Therefore, the study recommended that governments of Sub-Saharan African countries should implement policies and programmes capable of sustaining and improving inclusive growth in order to avoid high income inequality in the region.     &nbsp

Efficacy of Polyphosphoric Acid in Reducing the Degree of Thermal Aging of Agbabu Natural Bitumen

Bitumen is a complex mixture of hydrocarbons which occurred naturally or obtained from crude oil distillation. The degradation of bitumen causes its rapid aging leading to deterioration of asphalt based pavement readily induced by cracking, rutting, potholes etc. Aging in bitumen is attributed to chemical oxidation of its molecules and exposure to environmental factors, such as heat, moisture and sunlight. This study therefore investigates the viability of using polyphosphoric acid (PPA) to reduce the oxidative degradation effect of heat (60 o C) on constituents of Agbabu natural bitumen (ANB) with a view to making it more durable when used for road pavement. Modification of ANB with PPA was carried out at 150-55 o C using melt blend technique. Thereafter, the PPA modified and neat (unmodified) ANB samples were thermally aged in a hot air oven at 60 o C. Fourier Transform Infrared (FTIR) Spectroscopy was used to evaluate the changes in the structure of ANB and aging indexes of neat and PPA modified samples of ANB were calculated. The neat and PPA modified ANB samples aged as a result of their exposure to temperature at 60 o C. However, the aging indexes of PPA modified samples of ANB were found to be lower compared with that of the neat sample of ANB. This implies that the rate of aging (60 o C) of the neat ANB was faster than that of PPA modified ANB samples. Thus, a good potential for reducing thermal aging in ANB was found in PPA

Rearrangements and Dilatancy for Sheared Dense Materials

Constitutive equations are proposed for dense materials, based on the identification of two types of free-volume activated rearrangements associated to shear and compaction. Two situations are studied: the case of an amorphous solid in a stress-strain test, and the case of a lubricant in tribology test. Varying parameters, strain softening, shear thinning, and stick-slip motion can be observed.Comment: 4 pages, 3 figure

Flame/stretch interactions of heavy-hydrocarbon/O/N premixed flames

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76511/1/AIAA-1999-321-776.pd

Thermal quantum and classical correlations in two qubit XX model in a nonuniform external magnetic field

We investigate how thermal quantum discord (QD) and classical correlations (CC) of a two-qubit one-dimensional XX Heisenberg chain in thermal equilibrium depend on the temperature of the bath as well as on nonuniform external magnetic fields applied to two qubits and varied separately. We show that the behavior of QD differs in many unexpected ways from the thermal entanglement (EOF). For the nonuniform case (B1 = -B2), we find that QD and CC are equal for all values of (B1 = -B2) and for different temperatures. We show that, in this case, the thermal states of the system belong to a class of mixed states and satisfy certain conditions under which QD and CC are equal. The specification of this class and the corresponding conditions are completely general and apply to any quantum system in a state in this class satisfying these conditions. We further find that the relative contributions of QD and CC can be controlled easily by changing the relative magnitudes of B1 and B2. Finally, we connect our results with the monogamy relations between the EOF, CC and the QD of two qubits and the environment.Comment: 8 pages, 13 figures. We connect our results with the monogamy relations between the EOF, CC and the QD of two qubits and the environmen

Characterisation of Agbabu Natural Bitumen and Its Fractions Using Fourier Transform Infrared Spectrometry

Physico-chemical characterization of bitumen is very germane to its applications. There have been many physico-chemical investigations on Agbabu natural bitumen (ANB), but there appears to be some discrepancies in the results of some of the findings. Thus, the need to re-examine some of the physico-chemical parameters of the ANB. Raw sample of ANB was obtained from one of the observatory wells in Agbabu, Ondo State, Nigeria. The sample was dehydrated, purified and asphaltene component precipitated through addition of n-pentane to the sample. The maltene component was fractionated into saturate, aromatics and resin using column chromatographic method. The purified ANB sample and its fractions were each subjected to infrared analysis. In addition, the elemental composition and trace metals in the whole purified ANB were quantified using CHNS-O Analyzer (FlashEA® 1112) and Atomic Absorption Spectrometer (AAS) respectively. Infrared spectral features obtained for the whole bitumen and its fractions bear a good degree of resemblance to the results of earlier workers on the subject with some minor differences. The values obtained for structural indexes from Infrared (IR) spectra showed that all the fractions contained branch and straight chain hydrocarbons. The structural indexes also showed that asphaltenes and resin fractions are strongly polar, both of which contain hetero–atomic compounds. Results of compositional analysis are: C (86.62%), H(10.98%), S (0.92%) N (0.48%), O (0.83%), Maltene (78.34%) aand Asphaltene (21.67%). The concentrations of the trace metals are: Mg (792.00 ppm), Mn (28.40 ppm), Fe (3633.10 ppm), Ca (1082.10 ppm), Zn (17.50 ppm), Cu (17.90 ppm), Cr (153.90 ppm), Pb (93.78 ppm), Ni (103.65 ppm), V (156.53 ppm) and Na (3740.00 ppm). Results of compositional and trace metals analyses of this study are at variance with the earlier results on characterization of ANB in the literatures. The differences in the results might be attributed to variation in the method of sample preparation especially the inclusion of dehydration of the raw ANB in the purification step prior to characterization as introduced in this study. Keywords: Aromatics, Asphaltenes, Agbabu Natural Bitumen, IR, Resins, Saturate

Optimization of corrosion inhibition of essential oils of Alpinia galanga on mild steel using Response Surface Methodology

The use of plant extracts as corrosion inhibitors has gained prominence as replacement for synthetic organic compounds. The plant natural products have been found to be effective, cheap and eco-friendly anticorrosion agents. Corrosion inhibitions of essential oils of Alpinia galanga were investigated on mild steel in hydrochloric acid solution using weight loss method. The interactive effects of inhibitor concentration, temperature and time were optimized for maximum response of inhibition efficiency using Response Surface Methodology with Central Composite Design. The optimum inhibition efficiency of 88.5% at 775 ppm of inhibitor concentration, temperature of 320.4 K and reaction time of 3.75 hours was accomplished. The effectiveness of the inhibitor was also supported using scanning electron microscopy. The mechanism of interaction of both the inhibitor on mild steel surface was found to conform to the Langmuir adsorption isotherm