Linus Okoro | American University of Nigeria, Yola (original) (raw)

Papers by Linus Okoro

Industrial chemistry, Jul 11, 2016

I n this research we report the comparative energy content or heat value of alcohol fuels as well... more I n this research we report the comparative energy content or heat value of alcohol fuels as well as blends with gasoline and kerosene, obtained from glass, steel and bomb calorimeters. The energy content of the alcohol obtained from the two calorimeters differ widely from the ones obtained from bomb calorimeter; with the values of the energies obtained from the glass and steel calorimeters far less than the values obtained from the bomb calorimeter. However, we observed that the energy content of the alcohol fuels increased from methanol through to pentanol. Meanwhile, the energy of the blend increases with the increase in carbon content of the alcohol, except for blends beyond E15. Additionally, the blend of the fuels gave higher energy values than the pure alcohols using any of the methods. Biography Linus N Okoro is lecturing at the American University of Nigeria as an Associate Professor and the chair of petroleum chemistry department. He obtained his PhD in Physical Chemistry from the Dortmund University of Technology, Germany. He has published more than 20 papers in reputed journals.

Zeitschrift für Naturforschung B, Jun 1, 2008

Dedicated to Professor Gérard Demazeau on the occasion of his 65 th birthday Sterols regulate bio... more Dedicated to Professor Gérard Demazeau on the occasion of his 65 th birthday Sterols regulate biological processes and sustain the lateral structure of cellular membranes. The sterol cholesterol, its precursor lanosterol, the plant sterols stigmasterol and ergosterol as well as 7-dehydrocholesterol were added up to 36 mol-% to vesicles of the phospholipid 1,2-dipalmitoyl-snglycero-3-phosphatidylcholine (DPPC). The aim of this study was to investigate the influence of the sterol side chain and ring structure on the volumetric properties of the lipid bilayer system by using pressure perturbation calorimetry (PPC), a relatively new and efficient technique, to study the thermal expansion coefficient and volumetric properties of biomolecules. The experiments were carried out in the temperature range from 10 to 85 • C, i. e., at temperatures below and above the chain-melting transition temperatures of the lipid mixtures. Additionally, corresponding differential scanning calorimetric (DSC) measurements were carried out. Whereas the conformational properties of the different sterols have a significant effect on the order parameter of the lipid acyl-chains, the thermodynamic parameters of these sterols are less influenced by the differential structural changes of the sterols. For lanosterol and stigmasterol, marked differences are found, however.

Biophysical Chemistry, Jun 1, 2011

Pressure perturbation calorimetry (PPC) is a relatively new and efficient technique, to study the... more Pressure perturbation calorimetry (PPC) is a relatively new and efficient technique, to study the volumetric properties of biomolecules in solution. In PPC, the coefficient of thermal expansion of the partial volume of the biomolecule is deduced from the heat consumed or produced after small isothermal pressure jumps (typically±5 bar). This strongly depends on the interaction of the biomolecule with the solvent or cosolvent as well as on its packing and internal dynamic properties. This technique, complemented by ultrasound velocity and densitometry, provides valuable insight into the basic thermodynamic properties of solvation and volume effects accompanying phase transitions and interactions of biomolecular systems. Here we review data on protein folding, ligand binding processes, and phospholipid phase transitions, together with discussion of interpretation and further significant applications.

International journal of scientific and engineering research, Aug 25, 2014

The current study tested the hypothesis as to whether or not polyethylene-based plastic can be co... more The current study tested the hypothesis as to whether or not polyethylene-based plastic can be converted to liquid fuel by thermal catalytic cracking over metal oxide catalysts, including Ca(OH)2, Al2O3, and ZnO. To determine the optimum condition for the highest yield of low molecular weight (C5-C22, MW=100-300) liquid fuel production, the catalyst-to-polymer ratio was investigated at various temperature and reaction times. The initial liquid product obtained from each catalyst was further cracked to yield hydrocarbons of lower molecular mass. The obtained final products were analyzed by gas chromatography-mass spectrometry (GC-MS), high performance liquid chromatography (HPLC), infrared resonance (FT-IR), and elemental analysis (EA). The GC/MS analysis demonstrated that the fuel obtained had constituents ranging from carbon numbers of 5-22. The FT-IR spectra showed the expected functional group and the element analyzer indicated the gross and net heating values of the fuel to be within the range 61-383 MJ/Kg. Comparative analysis showed that Ca(OH)2 has the highest total conversion yield followed by Al2O3 and then ZnO.

European Chemical Bulletin, Mar 7, 2018

This research tested the hypothesis of whether fatty acid saturation and chain length of feedstoc... more This research tested the hypothesis of whether fatty acid saturation and chain length of feedstock oil has any effect on the physicochemical properties of synthesized kerosene-like fuel. Biodiesel was obtained from the feedstocks via transesterification and were subjected to distillation under vacuum between 50 to 100 o C to obtain kerosene-like fuel as the final product. The heat value, flash points, kinematic viscosity and specific gravity values were obtained and found to be within the stipulated range of fossil kerosene. The products were analysed using infrared spectrometer to confirm the presence of the functional groups in the kerosene-like fuel produced. Furthermore, Analysis by the elemental analyser showed that the kerosene-like fuel obtained from coconut oil has a significantly higher heat content value (9211.9 Kcal.Kg-1) than that from cashew-nut oil (5699.4 Kcal.Kg-1). This distinction in heat value can be ascribed to the nature of fatty acid in the oils as coconut oil is significantly more saturated and has shorter fatty acid hydrocarbon chain length than cashew-nut oil.

Journal of physics, Dec 1, 2019

View the article online for updates and enhancements. You may also like Production of an electrol... more View the article online for updates and enhancements. You may also like Production of an electrolyte drink from the use of tamarind fruit (Tamarindus indica L.

International journal of scientific and engineering research, Jan 25, 2017

The current study examined the thermal catalytic cracking reaction of polypropylene-based polymer... more The current study examined the thermal catalytic cracking reaction of polypropylene-based polymers to generate C8-C18 hydrocarbons using metal oxide catalysts, including MgCO3, CaCO3, Al2O3, and MgO. A systematic analysis of the liquid productswas performed to determine the optimum catalyst that produces a highest yield of C10-C12 hydrocarbon which falls under the gasoline range organics (GRO). Our data demonstrated that MgO produced the highest yield of liquid products compared to the other catalysts. The kinetic study suggeststhe potential mechanism of time and ratio (polymer vs. catalyst)-dependent polypropylene cracking. The hydrocarbon products were analyzed usingGC-MS and FT-IR to show that polypropylene cracking generates carbon constituents ranging from C8 to C18 which is a range for naptha, petrol, kerosene, and diesel. The FT-IR spectra demonstrated that hydrocarbon products contain mostly alkene and alkane functional groups. A massof polypropylene waste plastic were converted into potential kerosene fuel using 10%metal oxide catalysts producing 85% liquid, 3% light gas and 12% residues with 25 minutesof reaction timeand a first order reaction kinetics.The calorimetric analysis showed that the liquid has a heating value within a range of 9.8– 10.8Kcal/g.

The journal of the Cameroon Academy of Sciences, Jan 11, 2022

In this study, cellulose from sugarcane bagasse and wood pulp were converted to nanocellulose and... more In this study, cellulose from sugarcane bagasse and wood pulp were converted to nanocellulose and utilized to treat water from different sources within Yola Metropolis to study the efficacy of both methods. From the analysed water parameters, both nanocellulose materials were effective in treating contaminated water. They showed the capability of reducing the concentrations of the various tested parameters such as Total Dissolved Solids (TDS), Nitrate, Chloride, and Nephelometric Turbidity Units (NTU). Interestingly, analysis of the heavy metal concentrations before and after water treatment with the nanocellulose, showed very significant reduction of the heavy metals. This is encouraging as we explore more efficient methods of water treatment, in order to tackle rising cases of lead and other heavy metal poisoning in Nigeria due to illegal mining activities and deregulated industrial activities.

Biophysical Journal, May 1, 2008

Although sterol-phospholipid interactions have been of interest for many years now, a complete th... more Although sterol-phospholipid interactions have been of interest for many years now, a complete thermodynamic profile of these systems is still missing. To contribute to a better understanding of the thermodynamic functions of these systems, we determined isothermal compressibility coefficient data for dipalmitoylphosphocholine (DPPC) and DPPC-containing cholesterol and ergosterol vesicles by means of molecular acoustics (ultrasound velocimetry and densimetry) and differential scanning and pressure perturbation calorimetric techniques. A particular focus was on the influence of the differential structural properties of the two sterols on the thermodynamic properties of lipid bilayers, and on the nature of the critical point region of phospholipid-sterol systems by determining thermodynamic fluctuation parameters. Contrary to significant changes in conformational and dynamical properties of the DPPC-sterol membranes, no marked differences were found in the various thermodynamic properties studied, including the adiabatic (b lipid S) and isothermal (b lipid T) compressibility, as well as the volume fluctuations. Differences in b lipid T and b lipid S become dramatic in the gel-fluid transition region only, due to a significant degree of slow relaxational processes in the microsecond time range in the transition region. Our data show no evidence for the existence of a typical critical point phenomenon in the concentration and temperature range where a critical point in the DPPC-sterol phase diagram is expected to appear. Hence, on a macroscopic level, it seems more appropriate to describe the sterol-phospholipid binary mixtures in the liquid-ordered/liquiddisordered coexistence region as a phase region consisting essentially of small nanodomains only. Such small-domain dimensions, with a series of particular properties such as increased line energy, spontaneous curvature, and limited lifetime, seem also to be typical of raftlike domains in cell membranes.

Journal of the Cameroon Academy of Sciences, 2022

European Chemical Bulletin, 2014

In this research, we report biodiesel production and viscometric analysis from Mustard oil and Co... more In this research, we report biodiesel production and viscometric analysis from Mustard oil and Coconut oil, by subjecting the oil to a temperature of 65 o C through base catalyzed transesterification with the use of KOH as a catalyst. The biodiesel synthesized from Mustard oil was blended with petroleum diesel in the following percentage by volume 20%, 40%, 50%, 70% and 80% corresponding to B20, B40, B50, B70 and B80 respectively. The fatty acid methyl ester of Mustard oil was mixed with that of Coconut oil in the ratio of 80:20, 60:40 and 50:50 respectively. Viscometric analysis was carried out and the results obtained.

In this research we explored the calorific or heat value of alcohol fuels as well as blends with ... more In this research we explored the calorific or heat value of alcohol fuels as well as blends with kerosene by using both glass and bomb calorimeters comparatively. The calorific values obtained from the combustion of alcohol fuels from glass calorimeter were very much lower than those obtained from bomb calorimeter, as a result of heat loss in glass calorimer. The heat values, obtained by glass calorimeter, of methanol, ethanol, propanol, butanol, and pentanol gave 6.3MJ/Kg, 10.64MJ/Kg, 15.27MJ/Kg, 20.84MJ/Kg, and 22.56MJ/Kg respectively, while the heat values of methanol, ethanol, propanol, butanol, and pentanol, using the bomb calorimeter gave 16.36MJ/kg, 21.6MJ/Kg, 30.75MJ/Kg, 32.13MJ/Kg, and 36.1MJ/Kg respectively. It is observed that the heat value of each blend is greater as the percent of alcohol increases, but as the percent alcohol exceeds the percent kerosene, the heat value starts to decrease. Generally, the heating values of alcohol fuels increase as the carbon atoms incr...

Chromatographic analysis have been used in many ways in quantifying and identifying individual co... more Chromatographic analysis have been used in many ways in quantifying and identifying individual components in biodiesel samples, such as the identification of contaminants and Fatty acids methyl esters. Chromatography is vital in modern quality control analysis of biodiesel hence, its wide application in the study of biodiesel composition. These relevant studies have contributed immensely to the rapid growth of biodiesel production and analysis, with modern techniques providing better results. In this paper, several past research work on chromatographic analysis of Biodiesel from different oils have been reviewed.

Many scientists have through time developed interests in undertaking researches related either di... more Many scientists have through time developed interests in undertaking researches related either directly or indirectly to corrosion, which could be attributed to increasing cases of material breakdown as a result of corrosion. There are therefore several published works focused on studies of the corrosion behavior and mechanism of various metals in several different environments or media. In this review paper, we explored and analyzed the various recent research works on corrosion kinetics using weight loss method, and to a certain extent about corrosion inhibition.

This research was undertaken to examine possible corrosion in petroleum pipelines by determining ... more This research was undertaken to examine possible corrosion in petroleum pipelines by determining the corrosion kinetics of mild steel in a number of petroleum and biodiesel oil types. Weight loss measurements carried out for 25 days (at 5 days interval) showed corrosion rate was highest in Premium Motor Spirit (PMS) amongst petroleum refined products, followed in descending order by Dual Purpose Kerosene (DPK) and Automotive Gas Oil (AGO). Amongst 100% by volume biodiesels, coconut oil impacted more corrosion on mild steel, followed in descending order by olive oil and vegetable oil. Lastly, high corrosion rate was experienced in Russian crude oil (Urals) compared to its negligibility in Nigerian crude oil (Escravos). Among biodiesels and petroleum fractions, it has been observed that corrosion rate increases with decrease in density and increase in weight percent of hydrogen in the hydrocarbon media. High sulfur content has been found to account for the high corrosiveness of Russia...

The study of the interaction between matter and radiation is known as spectroscopy and it is seen... more The study of the interaction between matter and radiation is known as spectroscopy and it is seen as a suitable and precise analytical method in quality control analysis. Spectroscopy is vital in analysis of biodieselgiven that biodiesel has gained considerable attention in recent years due to its merits: biodegradable, renewable, non-toxic, less emission of gaseous and particulate pollutants with higher cetane number than normal fossil fuels. Spectroscopic methods could be atomic or molecular though modern techniques of acoustic, mass and electron spectroscopy do not involve the electromagnetic radiation. In this review, we studied various spectroscopic methods that have been used to evaluate the quality of biodiesel as well as observe the process of transesterification. Infrared, Nuclear magnetic resonance, Ultraviolet-Visible, Thermal lens and Mass spectroscopies are important analytical tools reviewed in this paper.

The rates of corrosion of zinc and copper materials at room temperature, 40°C and 60°C in biodies... more The rates of corrosion of zinc and copper materials at room temperature, 40°C and 60°C in biodiesels obtained from olive, groundnut and soya oils were studied. The study showed that copper materials have a higher corrosion rate in the biodiesels studied compared to zinc materials. The corrosion rate of zinc materials increased with increase in temperature of the biodiesels over a period of time.

Biodiesel is a monoalkyl esters of long chain fatty acids derived from renewable feedstock like v... more Biodiesel is a monoalkyl esters of long chain fatty acids derived from renewable feedstock like vegetable oils and animal fats. It is produced by transesterification in which oil or fat is reacted with a monohydric alcohol in the presence of a catalyst. In this research, transesterification process was used to convert olive oil and cashew nut oil into biodiesel (methyl ester). The selected material used in the preparation of this biodiesel was methanol, alkaline catalyst (KOH), constant temperature of 70 o C at 1.5hrs, to optimize the experimental conditions for maximum biodiesel yield. The thermodynamic properties of the biodiesel produced such as heat content of the pure biodiesel (B100) and the blends were investigated.

Heat of Adsorption of Tamarindus indica leaves extract and mild steel corrosion inhibition in for... more Heat of Adsorption of Tamarindus indica leaves extract and mild steel corrosion inhibition in formic acid solutions using Tamarindus Indica as natural inhibitor have been studied using gravimetric technique. Inhibition efficiency was observed to increase with an increase in Tamarindus indica leaf extract concentration. Temperature effect on the corrosion behavior of mild steel in 0.5M, 1M and 2M Formic acid solutions with addition of plant extracts was studied at the temperatures 30°C and 45°C. Optimum Inhibition efficiencies at 45°C are 76.18% for 0.5M, 74.88% for 1M, and 70.82% for 2M. Very low inhibition efficiencies are observed at 30°C. The adsorption mechanism proposed from the heat of adsorptions for 1M and 2M formic acid solutions is physisorption wh adsorption.

Biodiesel has become an important fuel in recent times due to its prospects as an alternative sou... more Biodiesel has become an important fuel in recent times due to its prospects as an alternative source of energy to petroleum fuels. In this research, biodiesel was synthesized form groundnut oil at 65 o C via base catalyzed transesterification using KOH as the catalyst. The synthesized fatty acid methyl ester after being washed was blended with petroleum diesel in the following percentage by volume of the biodiesel 2%, 5%, 10%, 20% and 30% corresponding to B2, B5, B10, B20 and B30 respectively. The heat content of each blend was measured using a bomb calorimeter. The data obtained was analyzed and was found that the heat content of the blend decreases as the percentage of biodiesel in the blend increases. The research also demonstrates that, the energy output of fuels made from blends of petroleum diesel and groundnut oil biodiesel decreases as the portion of the biodiesel increases.