Performance Evaluation of Abrasive Grinding Wheel Formulated from Locally Sourced Materials

This paper presents a study on the formulation and manufacture of abrasive grinding wheel using locally formulated silicon carbide abrasive grains. Six local raw material substitutes were identified through pilot study and with the initial mix of the identified materials, a systematic search for an optimal formulation of silicon carbide, the intermediate product, was conducted using the Taguchi method. The mixture was fired in a furnace to 1800oC for 6 hours forming silicon carbide chunks, which were crushed and sieved into abrasive grains that were used to produce the grinding wheels. These locally manufactured grinding wheels were further subjected to some mechanical tests and the test results show that they conform within the range of values specified in the international standard handbook

The effect of processing and preservation methods on the oxalate levels of some Nigerian leafy vegetables

Titrimetric analysis was used to estimate the level of oxalate in some Nigerian leafy vegetables treated in different ways in two sets of experiments. The treatments were boiling with retention of the water used for boiling, and freezing followed by boiling without retention of the water used for boiling. Results obtained showed that the former in which five different vegetables were used led to significant increases (

Determination Of Lipid Contents Of Two New Soy Bean Cultivars Using Gas Chromatography – Mass Spectrometry (GC-MS)

Determination of fatty acids and sterols in oil is very important as they serve as the vital indicators of the activity and purity, respectively of the oils. A qualitative Gas Chromatography – Mass Spectrometry study of oils from soy beans of two varieties (TGX 1802-1F, and TGX 1019-2EB) was done to determine their fatty acid, sterol and other compositions. The oils were extracted with n-hexane and concentrated in vacuo using rotary evaporator at 45 oC. The oils were slightly soluble in ethanol, insoluble in water and acetonitrile, and readily soluble in n-hexane, acetone, chloroform and benzene. The oils were preliminarily characterized using iodine value, acid value, specific gravity, volatile matter, saponification value and peroxide value. The acid values were 0.60 and 0.59 respectively, while the specific gravity at 30 oC was 0.919 for both samples. The volatile matters were 0.19 % and 0.17 %, and the peroxidevalues were 9.2 and 9.8 mEq/Kg respectively. Using an Agilient series 6890 Gas Chromatography system with a 5973 mass selective detector, the lipid composition of these oils was studied. Both cultivars were found to contain linoleic acid and pentadecadienoyl octadecadienoate. Palmitic acid and stearic acid were found in TGX 1802-1F, while TGX 1019-2EB was found to contain cholesterol and methyl octadecadienoate. This implies that TGX 1802-1F will be safe in applications where cholesterol free oils are desired. Also, the presence of linoleic acid in the oils indicate that they may be suitable as supplements for lowering the LDL cholesterol levels of the body as well as serve, via Gamma Linolenic Acid, in the biosynthesis of the very important anti – inflammatory 1 – series prostaglandins

In vitro evaluation of antioxidant activity of Anisopus mannii N.E. Br.

Anisopus mannii (Asclepiadaceae) –a plant widely used as an anti-diabetic agent in Northern Nigerian traditional medicine, was subjected to antioxidant evaluation. The crude methanol extract, n-butanol and ethyl acetate fractions were investigated for free radical scavenging activity of the 1, 1-diphenyl-2- picrylhydrazyl radical (DPPH), total phenolic contents and reducing power assay. The results of the DPPH free radical scavenging at 250 ìgml-1 indicated maximum antioxidant activity of 94.1, 94.3 and88.7% for crude methanol extract, ethyl acetate and n-butanol fractions, respectively. The total phenolic content was higher in the ethyl acetate fraction (59.60 mg/g gallic acid equivalent GAE) than in the nbutanolfraction (56.40 mg/g GAE) and crude methanol extract (53.20 mg/g GAE). The reducing power of n-butanol fraction was 0.112 nm higher than those of ethyl acetate fraction (0.110 nm) and crude methanol extract (0.106 nm). The antioxidant activities of the crude extract/fractions and the standards at maximum concentration of 250 ìgml-1 decreased in the order: ascorbic acid> ethyl acetate fraction> crude methanol extract> Gallic acid> n-butanol fraction, but there was no significant difference (p <0.05) between them. The phytochemical screening revealed the presence of flavonoids, tannins and saponins. This suggests a potential utility of the plant as a source of phenolic antioxidants and may provide leads in the ongoing search for natural antioxidants from Nigerian medicinal plants to be used in treating diseases related to free radical reactions

Evaluation of in vitro antimycobacterial activity of Nigerian plants used for treatment of respiratory diseases

The global threat of tuberculosis (TB) demands for search for alternative antimycobacterial drugs. Some Nigerian medicinal plants used in the treatment of TB and other respiratory diseases wereevaluated for activity against a clinical isolate of Mycobacterium tuberculosis and a strain of Mycobacterium bovis (BCG). The crude methanolic extracts of eight plant species were screened foractivity against a clinical isolate of M. tuberculosis using broth microdilution method. Four out of the eight plant extracts exhibited inhibitory activities against M. tuberculosis at 78 and 1250 µg/mL. Thecrude extracts of Entada africana, Hymenocardia acida, Sterculia setigera and Stereospermum kunthianum did not inhibit significantly even at high concentration of 1250 ìg/mL. The hexane fractionsobtained after fractionation were the most active fractions for all the plants tested against BCG, having Anogeissus leiocarpus and Terminalia avicennioides exhibiting the highest activity at 312 and 200µg/mL, respectively. Fractions Ta5 and Al4 obtained on further purification exhibited most significant activity (MIC of 4.7 and 7.8 g/mL, respectively). From the results of phytochemical analysis, terpenes and triterpenoid saponins are the most prominent compounds in these fractions and several reports earlier indicated that these metabolites are potential antimycobacterial agents. This class of metabolites presents interesting area for further investigation with special attention on the Combretaceae family from Nigeria flora

Hospital Prevalence of Haemoglobin C in Ilorin, Nigeria

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Dehalogenation of organic halides by flash vacuum pyrolysis over magnesium: A versatile synthetic method

Flash vacuum pyrolysis over magnesium at 600 degrees C results in efficient dehalogenation of a variety of organic halides and provides a preparatively useful method for C-C bond formation and other reactions.</p

Flash vacuum pyrolysis over magnesium. Part 1. Pyrolysis of benzylic, other aryl/alkyl and aliphatic halides

Flash vacuum pyrolysis over a bed of freshly sublimed magnesium on glass wool results in efficient coupling of benzyl halides to give the corresponding bibenzyls. Where an ortho halogen substituent is present further dehalogenation gives some dihydroanthracene and anthracene. Efficient coupling is also observed for halomethylnaphthalenes and halodiphenylmethanes while chlorotriphenylmethane gives 4,4'-bis(diphenylmethyl) biphenyl. By using, alpha,alpha'-dihalo-o-xylenes, benzocyclobutenes are obtained in good yield, while the isomeric, alpha,alpha'-dihalo-p-xylenes give a range of high thermal stability polymers by polymerisation of the initially formed p-xylylenes. Other haloalkylbenzenes undergo largely dehydrohalogenation where this is possible, in some cases resulting in cyclisation. Deoxygenation is also observed with haloalkyl phenyl ketones to give phenylalkynes as well as other products. With simple alkyl halides there is efficient elimination of HCl or HBr to give alkenes. For aliphatic dihalides this also occurs to give dienes but there is also cyclisation to give cycloalkanes and dehalogenation with hydrogen atom transfer to give alkenes in some cases. For 5-bromopent-1-ene the products are those expected from a radical pathway but for 6-bromohex-1-ene they are clearly not. For 2,2-dichloropropane and 1,1-dichloropropane elimination of HCl occurs but for 1,1-dichlorobutane, -pentane and -hexane partial hydrolysis followed by elimination of HCl gives E,E-, E,Z- and Z,Z-isomers of the dialk-1-enyl ethers and fully assigned C-13 NMR data are presented for these. With 6-chlorohex-1-yne and 7-chlorohept-1-yne there is cyclisation to give methylenecycloalkanes and -cycloalkynes. The behaviour of 1,2-dibromocyclohexane and 1,2-dichlorocyclooctane under these conditions is also examined. Various pieces of evidence are presented that suggest that these processes do not involve generation of free gas-phase radicals but rather surface-adsorbed organometallic species.</p