K. O. Ajanaku

Towards the conversion of carbohydrate biomass feedstocks to biofuels via hydroxylmethylfurfural

This review appraises the chemical conversion processes recently reported for the production of hydroxylmethylfurfural (HMF), a key biorefining intermediate, from carbohydrate biomass feedstocks. Catalytic sites or groups required for the efficient and selective conversion of hexose substrates to HMF are examined. The principle of concerted catalysis was used to rationalise the dehydration of fructose and glucose to HMF in non-aqueous media. A survey of reported reaction routes to diesel-range biofuel intermediates from HMF or furfural is presented and self-condensation reaction routes for linking two or more HMF and furfural units together toward obtaining kerosene and diesel-range biofuel intermediates are highlighted. The reaction routes include: benzoin condensation, condensation of furfuryl alcohols, hetero Diels–Alder reaction and ketonisation reaction. These reaction routes are yet to be exploited despite their potential for obtaining kerosene and diesel-range biofuel intermediates exclusively from furfural or hydroxylmethylfurfural.

Nigeria's Energy Challenge and Power Development: The Way Forward

The ever increasing demand and meager supply of energy in Nigeria has been a great challenge to her development. This situation is becoming critical, with increasing population not balanced by an adequate energy development programme. The incessant power generation failure has grossly affected the economy, seriously slowing down development in rural and sub-rural settlements, with present energy policy mainly benefiting urban dwellers. Globally, energy projections stipulate that between 2002 and 2025, global energy needs may rise by over 34%, with that of developing nations doubling this percentage. A robust solution must be found to end the nations energy crises. This Viewpoint compares the energy potential of Nigeria with the challenges faced. Nigeria receives a huge amount of solar radiation, has abundant wind energy resources, and large deposits of fossil fuel, as well as enormous hydro-power resources from Niger and Benue Rivers. However, of these about 80% of hydro-power remains untapped, the total 5.5KW-hr/m 2 /day of solar radiation is not utilized and wind energy resources remain unexploited. The solution lies in creating a mixed supply of energy in which as yet untapped renewable resources are combined with abundant non-renewable fossil fuel, including the massive quantities of gas wasted from crude oil exploitation.

Appraisal of Municipal Solid Waste Management, Its Effect and Resource Potential in A Semi-Urban City: a Case Study

Managing municipal solid wastes (MSW) is progressively becoming a major challenge in many cities of developing nations because of rapid urbanization and rise in population. This can be described by ineffective collection methods, inadequate coverage of the collection, processing system and inappropriate disposal. This paper presents the current state of solid waste management in a semi-urban city, its associated challenges and prospects that are within. A field work that involves the characterization and types of the waste generated, and frequency of collection was carried out within the study area. Four locations where the major waste bins are located within the city were considered. A representative sample of 280 kg was used for the waste characterization, and the results show that about 64% of the wastes are recyclable with lots of organic waste that can be used as compost. The only dump site in the city was visited in order to obtain useful information concerning the present state of solid waste management. The study revealed that there is presently no investment made to the existing development plan to introduce a modern waste management system. The study suggests new approach that could be used by institutions and government agencies for MSW management to realize a sustainable and efficient sanitation, and possible resources generation potentials that could be harnessed from the waste stream.

Characterization of diesel degrading bacterial species from contaminated tropical ecosystem

The bacterial diversity in a diesel contaminated tropical soil was investigated using diesel oxidation in gradient cultures dynamics (pH and OD) of the pure cultures. The diesel dependent growths of these isolates were assessed for 15 days by monitoring the gradient fluxes in the pH and Optical density OD of the media. Results showed an increase in OD as well as fluctuations in pH values. The mean OD data obtained was 0.515- 1.187 with pH of 6.95-7.2. From the morphological and biochemical characterization and comparison with respect to the standard references, the isolates S1P1, S3P3, S2P2, S2P1,and S3P2 were presumably the members of the genera Bacillus, Pseudomonas and Mycobacterium species. From the study, it was apparent that the tropical ecosystems contained unique organisms with the ability to deal with diesel contamination.

Structural, morphological and magnetic properties of La1−xNayMnO3 (y ≤ x) nanoparticles produced by the solution combustion method

The rapid solution combustion synthesis and characterization of sodium (Na)-substituted LaMnO 3 phases at relatively low temperature using polyvinyl alcohol (PVA) as fuel were reported. The thermal decomposition process investigated by means of differential and thermal gravimetric analysis (TG–DTA) showed that the use of PVA as a fuel was satisfactory in the synthesis of the perovskite manganite compound. Structural study using X-ray diffraction showed that all the samples were single phasic without any detectable impurities within the measurement range. Also, the Na-substituted compounds crystallize with rhombohedral symmetry (space group R-3c, no. 167) with La0.80Na0.15MnO3 manganite sample giving the highest crystallinity. Microstructural features observed by field-emission scanning electron microscopy demonstrated that most of the grains were nearly spherical in shape with fairly uniform distribution and all the observed particles connect with each other. Energy-dispersive X-ray analyses confirm the homogeneity of the samples. Increase in magnetic moment was observed with the increase in sodium doping. Room-temperature vibrating sample magnetometer measurements showed that the samples were ferromagnetic with compositions y = 0.10, 0.15 and 0.20 showing relatively high magnetic moments of 33, 34 and 36 emu g−1, respectively.

Modeling and Synthesis of Ag and Ag/Ni Allied Bimetallic Nanoparticles by Green Method: Optical and Biological Properties

In the quest for environmental remediation which involves eco-friendly synthetic routes, we herein report synthesis and modeling of silver nanoparticles (Ag NPs) and silver/nickel allied bimetallic nanoparticles (Ag/Ni NPs) using plant-extract reduction method. Secondary metabolites in the leaf extract of Canna indica acted as reducing agent. Electronic transitions resulted in emergence of surface plasmon resonance in the regions of 416 nm (Ag NPs) and 421 nm (Ag/Ni NPs) during optical measurements. Further characterizations were done using TEM and EDX. Antimicrobial activity of the nanoparticles against clinical isolates was highly significant as P < 0.05. These findings suggest application of Ag NPs as antibacterial agent against E. coli, S. pyogenes, and antifungal agent against C. albicans. Possible antibacterial drugs against S. pyogenes and E. coli can also be designed using Ag/Ni nanohybrid based on their strong inhibition activities. Similarly, the enhanced SPR in the nanoparticles is suggested for applications in optical materials, as good absorbers and scatters of visible light. Theoretical model clarified that the experiment observation on the relationship between metallic nanoparticles penetration through peptidoglycan layers and the activeness of microbial species depends on the nature of the nanoparticles and pore size of the layer.

Influence of transition metal ion (mn4+) on mullite formation in a mixture of 50:50 Nigerian kaolin and calcined alumina

Abstract In the present investigation, 5 wt% chemical grade MnO2 was added in a mixture of 50:50 Nigerian sources of kaolin and superfine calcined alumina powder and effect of this transition metal ion on their physico-mechanical properties, phase and microstructural evolution were studied during heating in the temperature range of 1,400–1,650°C. The heated samples were found to be highly porous (>30%) in this entire temperature range. The doping of 5 wt% MnO2 in this mixture did not improved the densification, but resulted into higher flexural strength (26 MPa) at 1,400°C compared to 7 MPa in the undoped sample. At 1,650°C, the reverse trend was observed, the flexural strength of undoped sample was found to be higher (38 MPa) than doped sample (27 MPa). The XRD study revealed the formation of mullite as major and corundum as minor phases in both the samples. The microstructural study shown the presence of needle shaped mullite crystals and corundum grains. The presence of inter-granular and intra-granular pores in MnO2 doped samples might have reduced the strength at 1,650°C. The aspect ratio of mullite needle at 1,650°C was found to be higher in doped sample. The theoretical and experimental value of >4 for MnO2 ion has been validated.

Corrosion Inhibitive Effect of 2-(1-(2-Oxo-2H-Chromen-3-Yl) Ethylidene) Hydrazine Carboxamide on Zinc-Aluminum Alloy in 1.8M Hydrochloric Acid

Introduction: Ethiopian communities highly depend on local plants to safe and sound their survival and health. Local trees are subjugated and used intensively for medicinal uses. Objective: The aim of the present study was too carried out phytochemical analysis of organic extract of Hagenia abyssinica and to find out antihelmentic property of Hagenia abyssinica. Methods: Hagenia abyssinica female flower extracts was used for plant component analysis and for determination of antihelmentic activity. Earth worm (Pheretima posthuma) strains were used for experimental purpose. Disc diffusion method was used to assess the antibacterial effect of the extracts on micro-organisms. Results: The phytochemical screening indicated the presence of flavonoids, tannins, steroid, alkaloid, saponins in all extracts. Antibacterial and antihelmentic activity of Ethanolic, Methanolic, Hexane and Petroleum Ether extract of Hagenia abyssinica female flowers was highly active against Adult earthworm (Pheritima posthuma) and active against Staphyloccoccus aureus and showed less activity against Salmonella typhi. Conclusion: The present study finally demonstrates that Hagenia abyssinica is a good source of various phytochemical such as Saponins, Phlobathanins, Flavonoids, Anthraquinones, Phenols, Terpenoids, Alkaloids, Steroids, Glycosides, Tannins. The antibacterial activity Hagenia abyssinica was clearly shown by the present study against bacteria. All these preliminary reports affirm an in depth analysis of the usefulness of Hagenia abyssinica as miracle drug against various ailments.

Improving Nutritive Value of Maize-Ogi as Weaning Food Using Wheat Offal Addition

The deficiency in affordable nourishing foods for neonates after weaning has been major concern in developing countries and this has contributed to increased malnutrition rate, illnesses and even children’s mortality rate. The addition of wheat offal to traditionally affordable ‘Ogi’ as an alternative approach for combating the threats of protein malnutrition in neonates was explored in this work. Wheat offal was added at increasing levels of 0, 20, 40, 60, 80 and 100 w/w% as fortifying feed with prepared maize-Ogi as meal. Proximate analysis, pasting characteristics, sensory evaluation, nutritive and functional properties of the resulting blends was evaluated using standard methods. Results of proximate analysis showed an increased protein (2.787 – 34.064%), fat (2.282 – 9.015%) and ash (8.913 – 17.171%) contents with increased level of wheat offal from 20 to 100 w/w addition, while decreased carbohydrate content was observed with increased addition of wheat offal. The water absorption capacity increased also with level of wheat offal addition. The pasting characteristics result indicated up to 40% fortification of maize-Ogi with wheat offal as stable blend against retrogradation in terms of setback value and viscosity. The 40% level of fortification was preferred in terms of quality index of taste, texture, color, sourness and appearance. In conclusion, the nutritional indices investigated indicated addition level of wheat offal to 40% limit to solve protein-energy malnutrition and food security issues in neonates.

Techno-Economic Assessment of Renewable Hybrid Systems for Rural Electrification and Distributed Generation in Selected Sites across Nigeria

The study considered the potentials and economic feasibility of solar and wind energy resources for rural-electricity and distributed generation from six selected sites of Nigeria. Remote communities cut off from the central grid and made up of 200 homes, a school and health centre were conceived a site per geopolitical zone was investigated. A specific electrical load profile was then developed to suite the rural communities. In view of this, the design that will optimally meet a daily load demand with 1% LOLP was carried out by considering standalone PV, Wind and Diesel systems design, as well as a Wind-PV hybrid system design. Further to this, an analysis covering the same sites was carried out to determine the commercial viability of generating and distributing electricity in the Megawatt range via distributed generation. The 24 years’ (19872010) solar, wind and other meteorological data utilized in this study was obtained from the Nigeria meteorological centre, Oshodi. The results of the study revealed that wind standalone system is the most economically viable substitute for power generation at most of the sites with costs ranged between