Synthesis and characterization of Bis (3-hydroxy-3-phenyl-1-O-carboxyphenyl triazene) Manganese (II) complex

3-hydroxy-3-phenyl-1-o-Carboxyphenyltriazene (HT) was synthesized by coupling ethanolic solution of diazonium salt of 2-aminobenzoic acid with phenylhydroxylamine in 1:1 molar proportion at 0-5OC in a refrigerator. Interaction of ethanolic solution of the ligand and aqueous solution of Manganese (II) sulphate heptahydrate formed bis (3-hydroxy-3-phenyl-1-o-carboxyphenyltriazene) Manganese (II) monohydrate. The ligand is soluble in many organic solvents; however, it is slightly soluble in water. Similarly the Manganese (II) complex is soluble in some organic solvents and water. The molar conductance of the complex is 36.7 Ohm-1Cm2Mol-1 which is quite low, suggesting that the compound is non-electrolyte. The complex compound decomposed at 208OC, indicating good thermal stability. The infrared of the ligand and the complex showed bands, which are attributable to ʋ (N=N) stretching vibration at 1397 and 1400 Cm-1s. The bands at 3425 and 3463 Cm-1 are assigned to ʋ (O-H) vibration in the complex and the ligand respectively. The empirical formular calculation from gravimetric analysis results revealed a 1: 2 metal to ligand ratio.Keywords: Schiff base complex, 3-hydroxy 3- phenyl-1-o-carboxyphenyltriazen

Synthesis, Antibacterial and Antifungal Investigations of Mn (Ii) Complexes with Schiff Bases Derived From 2 – Hydroxy – 1 – Naphthaldehyde and Some Aliphatic Diamines

Schiff base ligands derived from 2-hydroxy-1-naphthaldehyde and some aliphatic diamines were synthesized and characterized. Each of the ligands was used to form complex with Mn (II). Solubility, elemental analyses and IR spectra were carried evaluated. Elemental analyses of the complexes for C, N and H revealed 1:1 metal to ligand ratio. Antibacterial and antifungal activities were determined. Disc diffusion method was employed for these antimicrobial assays against four pathogenic bacteria (Escherichia coli, Salmonella typhi, Proteus sp. and Klebsiella pneumonae) and two fungi (Mucor sp. and Rhizopus sp.). It was found that the ligands and the complexes showed different activities against the isolates. The complexes showed higher activity than the free ligands. Keywords: Schiff base, diamine, ligand, complex, isolates, analysi

Characterization of Schiff base derived from 2-hydroxo-1-naphthaldehyde and Ethylenediammine and its Copper (II) Complex by Potentiometric and Spectrophotometric Methods

Synthesis of Copper (II) complex with a Schiff base derived from the reaction of 2 – hydroxyl-1- naphthaldehyde and ethylenediammine was carried out. Solubility, melting/decomposition temperature, molar conductance, potentiometric, elemental analysis as well as uv-visible spectrophotometric studies were carried out. The pKa of the Schiff base was determined potentiometrically and checked using ORIGIN 50 method. Potentiometric studies revealed 1:1 metal to ligand ratio. Job’s method of continuous variation also revealed 1:1 metal to ligand ratio. Molar conductance measurements showed that the complex is non electrolyte with very high stability constant value. Gibb’s free energy determination showed that the complex is very stable as shown in the high decomposition temperature measurements.Keywords: Potentiometry, Schiff base, Spectrophotometry, Stability constan

Strategic Slug Flow Attenuation in Pipeline-Riser Systems

Oil and gas activities across the globe now take place deep offshore. To operate in this harsh environment, there are numerous challenges. These can be in the form of high cost of production, space constraints, operational and technological demands. The co-transportation of oil and gas in same pipeline is one of the operational and technological approaches adopted in the industry to meet the transportation of produced crude. This approach comes with its attendant flow assurance difficulties. Slugging is one of such problems which can constitute operational hitches resulting in production reduction and sometimes eventual plant shutdown. Existing attenuation techniques are limited in various ways. Therefore, seeking a reliable solution to this problem is highly desired. In this study, an experimental study of multiple techniques for slug attenuation was attempted. A passive device-the intermittent slug absorber, strategically combined with topside choking as well as topside separator were investigated. The theoretical analysis showed that slug attenuating devices can be combined in parallel to reduce the resistance posed on flow, leading to increased flow. The experimental results showed that a combination of the methods proves to be more effective compared to individual techniques. A significant reduction in riser- base pressure of up to 39% was achieved. This is advantageous and translates to an increase in oil recovery. Thus, the proposed strategy helps to achieve system stability and improved production at a lower cost

The application of tannin extract from Anogeissus leiocarpus plant as wood adhesives

This work reports the extraction and application of tannins as wood- adhesives from Anogeissus leiocarpus plant using water, acetone or a mixture of these as solvent. In terms of the quantity of extracts from polyphenolic extract of Anogeissus leiocarpus bark, water was the most effective solvent, followed sequentially by acetone and solvent mixture (90% acetone and 10% water). The use of solvent mixture in tannin extraction yielded high tannin content. The poly condensation reaction of Anogeissus leiocarpus bark extract is influenced significantly by amount of formaldehyde (9.0 ml), tannin (2.5 g), glycerol (0.6 ml), cure temperature 80OC, types and pH 7.5 of the adhesive medium. Adhesive joint of significant bond strength were obtained from Anogeissus leiocarpus tannin adhesive. Prolonged cure periods particularly at elevated temperature have adverse effect on the strength properties of these joints, especially with wood- panels as substrates. Joint prepared with adhesive derived from these extracts were tested for strength properties.Keywords: Anogeissus leiocarpus, tannin, polycondensation, Formaldehyde, cure temperature

Potential application of resin extracts of Anogeissus leiocarpus plant

This work reports the application of tannin obtained from Anogeissus leiocarpus plant and its use in formulation of a thermosetting material for domestic and industrial use. The ploy condensation of tannin with formaldehyde produced a thermosetting resin with useful properties; formaldehyde (10.5 ml), tannin (2.5 g), glycerol (0.6 ml), hexamine (5.5 g), pH 7.5 and temperature 60 °C. Gel viscosity and effect of temperature on gel time were determined. Absorption behaviour of the films from the thermosetting material formulated under aqueous, acid and basic conditions were investigated. Water absorption up to 90% was obtained between 1 to 3 hrs. Perhaps due to differences in chain topology of the material formulated related to the molecular size holes in the polymer structure which depends on the morphology and crosslink density of the material. No acid absorption was observed after 12 hrs indicating that cross-linking reaction was still taking place in the solution.Keywords: Thermosetting, Resin, Polycondensation, Tannin, polymerization, viscosit

A 5 year review of the prevalence and feto-maternal outcome of eclampsia at Aminu Kano teaching hospital.

Background: Eclampsia remains a serious obstetric disorder in tropical obstetric practice. Provision of quality antenatal care is essential in reducing its incidence.Objective: To determine the prevalence and socio demographic characteristics of patients with eclampsia and also the feto-maternal outcome.Study Design: A 5-year retrospective study on eclampsia in Aminu Kano Teaching Hospital, Kano.Results: There were a total of 13,750 deliveries and 240 eclamptic patients during the study period, giving a prevalence of 1.75%. About 49.28% of the eclamptic patients were adolescents compared with 7.25% in the control group and 59.42% of them were primigravidas compared with 12.56% in the control group. About 91.30% of the cases were Hausas and 77.77% were from Kano metropolis. Also 82.9% of the cases were unbooked and 51.29% of them were delivered via caesarean section compared with 10.63% in the control group. Maternal mortality occurred in 12.08% of the cases compared with 0.97% in the control group. Perinatal mortality occurred in 22.71% of the cases compared with 3.86% in the control group.Conclusion: Eclampsia is one of the serious emergencies seen in Sub-Saharan Africa and is associated with increased perinatal morbidities and mortalities. Providing good quality antenatal care coupled with improving emergency capability of hospitals and establishg an intensive care unit for the care of eclamptic patients are essential in reducing maternal and perinatal morbidities and mortalities from the disease.Keywords: Eclampsia, Feto-maternal outcome, AKTH Kano

Probabilistic Evaluation of Eurocode 5 Fire Design Criteria of a Timber Portal Frame

Structural reliability analysis for a three-hinge timber portal frame subjected to fire was undertaken. Eight modes of failure were identified for the frame and limit state function was formulated for each failure mode. The limit state functions were based on the Eurocode 5 design criteria. Uncertainties in the timber material properties were generated from laboratory test results performed on five commonly used timber species in Nigeria, namely Alstonia boonei (Ahun), Triplochiton Scleroxylon (Obeche), Terminalia Ivorensis (Idigbo), Terminalia superba (Afara) and Lophira Alata (Ekki). Uncertainties in loading and geometrical properties were obtained from international references. The limit state functions were evaluated using nonlinear constrained optimization technique. The optimization was executed using Genetic Algorithms(GA) based First Order Reliability Method (FORM) algorithm, through a developed computer programme in MATLAB. The results indicated that, the predominant mode of failure for a three-hinged timber portal frame in fire is the failure of the rafter-column connection that resulted to least safety levels for all the considered fire exposure times. Also, it was observed that at the critical mode of failure the portal frame can sustain fire for up to 50 minutes before failure, however, the target safety index of 3.8 recommended in the Eurocode can only be achieved at fire exposure time less than or equal to 25 minutes.http://dx.doi.org/10.4314/njt.v34i1.

Synthesis and Physicochemical Properties of Copper (II) Complex with a Schiff base Derived from 2 – Hydroxy – 1 – naphthaldehyde and Ethylenediammine

Synthesis of Copper (II) complex with a Schiff base derived from the condensation of 2 – hydroxyl-1-naphthaldehyde and ethylenediammine was carried out. Solubility, melting/decomposition temperature, molar conductance, potentiometric as well as uv-visible spectrophotometric studies were carried out. The pKa of the Schiff base was determined potentiometrically and checked using ORIGIN 50 method. Potentiometric studies revealed 1:1 metal to ligand ratio. Job’s method of continuous variation also revealed 1:1 metal to ligand ratio. Molar conductance measurements showed that the complex is non electrolyte with very high stability constant value. Gibb’s free energy determination showed that the complex is very stable as shown by the high decomposition temperature measurements.Keywords: Complex, Potentiometry, Schiff base, Stability constan

Performance evaluation of 200W solar photovoltaic panel considering Bauchi microclimatic conditions

Measurement and modeling of broadband and spectral terrestrial solar radiation is important for the evaluation and deployment of solar renewable energy systems. This paper focuses on optimizing the performance of 200W solar module taking into consideration the local climatic conditions of Bauchi locality. The uncertainty in life cycle savings for solar thermal and photovoltaic (PV) systems as linearly correlated with uncertainty in solar resource data. These uncertainties paved way for the need to conduct a critical assessment of the resource. Assessment of the solar resource for these technologies rely upon measured data, where available. In this paper, we present the development of mathematical model of photovoltaic solar cells based on their detailed single diode equivalent circuit representation. Pertinent simulation models for PV solar module both for an ideal weather situation and for taking into consideration the effects of microclimatic conditions that prevail in Bauchi as evaluated and compared with benchmarks available. The complete model of the PV system was implemented using MATLAB/Simulink platform. The standard characteristic curves for the 200W solar panel are as presented. The simulation of the ideal PV system made use of standard test conditions (STC) to facilitate comparison with the existing benchmark results in the literature. The analysis of the characteristics performance curves returned an average VOC = 42.9v and ISC = 4.21A. The simulation results further revealed that the power delivered by the 200W monocrystalline solar module of 144.3W @620W/m2, 35ºC as recorded for Bauchi under all climatic conditions as evaluated. The benchmark values obtained in the laboratory are VOC = 45.5V, ISC = 5.92A and 200-W under the Standard test condition (STC) conditions of cell temperature 25ºC, solar irradiance of 1000W/m2 and air mass (AM) of 1.5. The average conversion efficiency and fill factor as evaluated are 0.77 and 16% respectively. This result agrees with the benchmark of module efficiency of >15.66% recorded at STC. The results conclusively reveal that the microclimate of a locality essentially affects the performances of solar PV systems deployed to each location on the globe. Therefore, utilization of these parameters is essential for consideration in the design of solar systems in all localities