THE OPTIMIZATION OF FLOW RATES OF AN EXTRUDER

<p>ENGLISH ABSTRACT: The article addresses how the flow rates of an extruder can be optimized. It mentions the plastic recycling industry as an example, which is only one of many solid waste recycling industries. The literature on flow rates is reviewed to demonstrate a gap that the current study aims to fills, in the hope that it will stimulate further research in a fertile area.</p><p>AFRIKAANSE OPSOMMING: Die artikel adresseer die vraagstuk van vloeitempo van ‘n ekstrusieproses. Dit handel met ‘n voorbeeld van ‘n plastiekherwinningsproses wat spruit uit soliede afvalverwerking. ‘n Literatuurstudie toon hoedat die navorsing verdere areas wat braak lê, aanspreek in die hoop dat verdere studie gestimuleer sal word.</p&gt

Management of anthracnose disease of cowpea with three plant leaf extracts for enhanced grain yield in Abeokuta, Nigeria

The antifungal activity of aqueous three plants leaf extracts were tested against anthracnose disease of cowpea caused by Collectotrichum lindemuthianum. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replicates. Extracts of Azadirachta indica, Acalypha wilkisiana and Carica papaya were sprayed on cowpea (Ife brown) foliage. A total of four foliar sprays were applied: three wee ks after planting, flowering stage, at the initial podding stage and at the full podding stage. Benlate served as positive controls while distilled water was negative control. Results showed the disease incidence and severity as 23.67-46.67% and 1.07-1.93, respectively. Combination of the extracts resulted in significantly (p≤0.05) low incidence of anthracnose (66.67% reduction) and improved the yield of cowpea by 1.63 tons/ha (77.25% increase) compared with untreated control plots. Azadirachta indica, Acalypha wilkisiana and Carica papaya extracts, singly or in combinations, reduced incidence and severity of anthracnose which translated to yield increase. Keywords: Anthracnose, botanicals, Collectotrichum lindemuthianum, cowpea, and managemen

Sexual practices and its predictors among in-school adolescents in an urban city in North Central Nigeria

Objective: To assess the sexual practices and its predictors among in-school adolescents in Ilorin metropolis, Nigeria.Methods: A descriptive cross-sectional study design was employed, using a pretested semi-structured interviewer administered questionnaire from 400 respondents via multistage sampling technique.Results: Almost half of the respondents (47.5%) have had only one sexual partner before and more than half of them (52.5%) have had two or more partners. Less than one fifth of the respondents (18.0%) had had sexual intercourse. More than half of the respondents (56.9%) who were sexually active used condom at first experience. Respondents' age, gender and religion were important predictors of sexual behaviour.Conclusion: Risky sexual practices are high in Nigeria and young people especially girls are at risk of morbidity and mortality due to sexually transmitted infections including HIV/AIDS, complications from unsafe abortion and social exclusion from stigmatization thereby calling for extra attention to this population.Key words: Adolescents, sexual practices, risky sexual behaviour, sexually transmitted infections

Energy output assessment of Lafia-Obi coal in a fluidized bed combustor

This work investigated the energy output from the fluidized bed combustion of Lafia-Obi coal using five range of fuel equivalent diameters (FED) of 125 μm, 250 μm, 355 μm, 2.5 mm and 5.0 mm. Energy output in response to variation in bed temperature, FED, bed pressure, and fluidizing velocity was examined in the fluidized bed heat exchanger. Results indicated an increase in heat transfer rate by 80, 11 and 25% when 5 mm coal was reduced to 355, 250 and 150 μm respectively. Bed temperature increased by 8% for 355 μm and decreased by 6% when 5.0 mm coal was fired. Higher bed pressure was observed when larger particle sizes (5.0 and 2.5 mm) were fired. This resulted in poor bed temperature and increasing fluidization velocity and thus, reduced steam discharge temperature at the heat exchanger outlet.Keywords: Lafia-Obi coal, energy output, fluidized bed, particle size, bed temperature, combustion efficienc

Organisational Support, Knowledge Sharing and Utilisation as Correlates of Social Capital of Insurance Managers in Lagos Metropolis

Managers in insurance companies in Nigeria went through a difficult period after the recapitalization which was aimed at achieving a consolidation that will produce companies capable of meeting claims obligations, compete at the continental and global levels, increase the industry’s low retention capacity which had stunted its growth among others. This study therefore examined the organisational support, knowledge sharing and utilisation as correlates of social capital of insurance managers in Lagos metropolis. This research adopted the correlation type of descriptive survey design to determine the direction and degree of the relationship or association between variables. Total enumeration technique called census coupled with a self-developed questionnaire was used to collect data on a population size of 280 managers in 23 insurance companies in Lagos metropolis, out of which 211 responded giving a response rate of 75.4 percent.The study found out that organisational support, knowledge sharing and utilisation had significant multiple effect on social capital of the respondent (R = 0.656, p < 0.05). In addition, each of the independent variables, namely, organisational support, knowledge sharing and utilisation significantly predicts the social capital of the respondents respectively.The study recommends among others that knowledge utilisation and information literacy education should be inculcated in the training of managers since they are the critical decision makers in the firm. This may improve the managers’ ability to exploit the sum of the actual and potential resources embedded within, available through, and derived from the their network of relationships. This may also encourage the managers to freely exchange ideas, insight, information and knowledge.. Keywords: Organisational support, knowledge sharing, knowledge utilisation, Insurance companies, Nigeria

Consumers' acceptability of iodine-biofortified tomato in Abeokuta, Southwestern Nigeria

Higher exposure rate to certain chemicals found in processed foods that reduce iodine absorption and a depletion in the amount of iodine found in soil have been reported to be detrimental to health. This study seeks to examine the consumers' acceptability and willingness to pay a price premium for iodine-enriched tomatoes in Abeokuta, southwest, Nigeria. Primary data were used to collect a sample of 300 respondents. The data were analyzed by descriptive statistics and Contingent Valuation Method (CVM) under double bounded dichotomous choice approach. The use of dichotomous choice (DC) method in explaining the willingness to pay (WTP) in contingent valuation studies is a common method in Economics. Research has shown that double-bounded Dichotomous Choice methods provide statistically superior outcomes than single bounded methods, given appropriate sampling design. Results from the socioeconomic characteristics of the respondents revealed a mean age of 42 years and are mainly (83%) in their economic active age (<50 years), 69% male respondents, 63% were married and 53% of the respondents had prior knowledge of iodine-biofortified tomato. It was also revealed that 58% of the respondent are willing to accept and pay a premium for iodine-biofortified tomato. Although, the proportion of the respondents who were willing to pay generally decreases with increases in price. It is concluded that age, level of education, income, prior knowledge and bid price were the significant factors influencing respondents' willingness to pay a price premium for iodine-biofortified tomato in the study area.Keywords: acceptability, contingent valuation method, iodine-biofortified tomato, price premiu

The roles of biochar and arbuscular mycorrhizal inoculation on selected soil biological properties and tomato performance

Field experiment was conducted to investigate the effects of biochar application and arbuscular mycorrhizal (AM) inoculation on selected soil biological characteristics, shoot P and fruit yield of two tomato genotypes. Result indicated that mycorrhizal inoculation significantly (p< 0.05) increased shoot P (0.72 g P kg-1) and number of AM spores (47.90 spores / 25 g soil) compared to non-mycorrhizal plants, but no significant difference was observed in tomato fruit yield, microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN). Application of 20 t ha-1 of biochar significantly (p< 0.05) increased tomato fruit yields and number of AM spores when compared with the control. However, 10 and 15 t ha-1 of biochar rates gave comparable performance as 20 t ha-1 of biochar in most cases. No significant differences were observed in shoot P, MBC and MBN among biochar rates. Thus, AM inoculation enhanced P nutrition while biochar improved AM spores abundance as well as tomato fruit yields. The 20 t ha-1 of biochar could be used to improve AM spores abundance as well as tomato fruit yields.Keywords: Biochar; AM Fungi; Biological Properties; Tomato Performanc

Morphological and biochemical characterization of strains of Xanthomonas axonopodis pv. vignicola isolated from cowpea grown in three agroecological zones in Nigeria

Cowpea bacterial blight (Xanthomonas axonopodis pv vignicola) is a devastating disease of cowpea in Nigeria. Accurate identification is the first step for an effective management option. Thus, X. axonopodis pv. vignicola isolated from cowpea (Vigna unguinculata (L.) Walp) grown in different Agro-ecological zones in Nigeria were characterized using morphological characteristics, biochemical and antibiotic sensitivity tests. Pot experiments were conducted on two susceptible lines of cowpea (IT90k – 76) and (IT84s – 2246 – 4) in the screen house. In vivo infectivity studies were carried out to determine the effect of each of theX. axonopodis pv. vignicola isolate groups on the cowpea. All isolates from each of the agroecological zones were classified into Group 1 (light yellow) and Group 2 (brownish yellow) based on their morphological presentation on nutrient agar medium. Results from four of the biochemical test showed differences between the two morphologically different groups. Group 2 isolates showed a large zone of inhibition to a Lincomycin hydrochloride while isolates from Group 1 were not affected by the action of the same antibiotic. Blight symptom was only observed when the two types of isolates were combined and inoculated simultaneously. This study showed that there are two morpho-types of X. axonopodis pv. vignicola and their synergetic infectivity results in blight symptoms expression in cowpea

Study of Influence of Zinc Plated Mild Steel Deterioration in Seawater Environment

The corrosion resistance of electrolytic zinc-coating on mild steel in seawater was investigated. Mild steel samples were zinc electroplated at voltage varied (0.6, 0.8, 1.0, 1.5 V) and for plating time also varied (20, 30, 40, 50, 60 minutes). Focused ion-beam scanning electron microscopy was used to observe the surface morphology of the plated surface. The visual observation of plated samples revealed that samples plated at 0.6 V for 20 and 60 minutes; 0.8 V for 30 minutes and 1.0 V for 40 minutes showed the best physical properties such as colour, brightness, fineness, streak and strong adhesion. The plated samples were then subjected to seawater environment for 30 days. The electro-potentials mV (SCE) was measured daily. Weight loss was determined at intervals of five days for the duration of the exposure period. Experimental result showed little corrosion attack on the zinc-plated samples on the fifteenth and twenty-fifth day’s exposure. The severity of attack decreases with increasing weight of zinc coated on substrate. Significant increases in the corrosion resistance were achieved for the plated samples compared with that of the substrate. The pH of the seawater became more alkaline at the end of the thirty days test

Structure of Plants across Habitat Types in Amurum Forest Reserve, Plateau State Nigeria

The Amurum Forest Reserve is one of the nature reserves in Plateau State North central Nigeria. Strict Nature reserve is prominent among the methods for in situ conservation of biodiversity in Nigeria and also the world at large. A study was conducted in the Forest across three habitat types in order to measure tree height and diameter at breast height (dbh) of trees. 50m x 50m plots were marked across the habitat types by simple random sampling technique. Trees and shrubs were identified to species level. Measurement were limited to all woody plants with diameter at breast height (dbh) of ≥ 10cm. Data collected was analyzed in excel. A total of 397 woody species were identified during the study period. 87.7 of the plants were shrubs while 12.3% were trees. The gallery forest had the highest diameter class(30-35cm) followed by the savanna(25-30cm) and lastly the rocky outcrop with the diameter class of 20-25cm.The rocky outcrop had the highest number of trees with the lowest dbh (10-15cm) while the gallery forest had more trees in the highest diameter class (30-35) (Figure 2). The highest mean height distribution in the Gallery forest shows that the plant communities in this habitat type has grown over the years without disturbance since the place is a protected site. Therefore, other surrounding bushes should be protected in order to preserve species from local extinction