The Effect of Weather Factors on the Population Density of Oxycarenus spp. (Hemiptera: Lygaidae) on Roselle and Kenaf

Roselle, Hibiscus sabdariffa and Kenaf, Hibiscus cannabinus are two important fibre crops in most parts of Africa. Insect pests are one of the major constraints in the production of these crops. The cotton seed bug Oxycarenus spp. attacks Roselle and Kenaf during the seed formation stage and cause reduction in seed viability. This study examined the effect of weather factors namely, relative humidity, temperature, sunshine and soil evaporation on the population density of Oxycarenus spp. on Roselle and Kenaf during the planting seasons 2012 and 2013. The treatments consisted of two types of Roselle (Green-calyxed and Redcalyxed) and Kenaf. The experiment was laid out in the field using Randomized Complete Block Design and the treatments were replicated four times. The results showed that the population of Oxycarenus spp. was significantly (p<0.05) higher on green-calyxed H. sabdariffa and red-calyxed H. sabdariffa than on Kenaf in 2012 and 2013. The differences in the density of the bug per fruit on green-calyxed H. sabdariffa and redcalyxed H. sabdariffa were significant in the two planting seasons. Relative humidity in the morning and maximum temperature correlated positively and negatively, respectively with the density of Oxycarenus spp. during the two planting seasons. Sunshine hours per day correlated positively, while soil temperature and soil evaporation had a negative correlation with the bug density. This information on the seasonal variation in the bug density and its relationship with weather factors could be used in pest forecasting for these fibre crops which is an important tool in formulating a successful pest management programme.Keywords: Malvaceae, Fibre crops, weather factors, Oxycarenus spp., pest management, planting seasons, pest density

Extraction Of Fetal Electrocardiogram Using An Adaptive Neuro-Fuzzy System

In this paper, adaptive neuro fuzzy inference system (ANFIS) was used for the cancellation of maternal electrocardiogram (MECG) in fetal electrocardiogram extraction (FECG) from the composite abdominal electrocardiogram (AECG). This technique is used to estimate the MECG present in the abdominal signal of a pregnant woman. The FECG is then extracted by subtracting the estimated MECG from the abdominal signal. In the furtherance of extraction, MATLAB (version 7.6) was used to code the system in order to generate the maternal heartbeat signal and the fetal heartbeat signal which were added to form the measured signal. For the fetal heartbeat signal to be recovered from the interference (maternal heartbeat) signal, a reference signal (which is a clean version of the original maternal heartbeat signal) was introduced in the system. It is this signal that cancelled the maternal heartbeat signal in the measured signal, thereby leaving the fetal heartbeat signal as an error signal. However, though the recovered signal still contained some traces of the maternal heartbeat signal, performance of the soft computing technique applied is in terms of the capability of adaptive neuro fuzzy inference system in removing the overlapping between the MECG and the FECG signals. The results obtained show that this method is a simple and powerful means for the extraction of Fetal Electrocardiogram.   Keywords: Fetal Electrocardiogram Extraction (FECG), Neuro-fuzzy system, Noise Cancellatio

INFLUENCE OF CATALYST QUANTITY AND REACTION TIME ON IN-SITU PRODUCTION OF BIODIESEL FROM RAW CASTOR BEAN SEED USING RESPONSE SURFACE METHODOLOGY

Trans-esterification is the most commonly used methods of biodiesel production. In-situ trans-esterification process uses oil (triglycerides) in seeds directly without the need for initial extraction. The in-situ production of biodiesel from raw castor bean seed with a batch processor was studied at initial catalyst quantity of 0.1, 0.5 and 1.5%, reaction time of 30, 60 and 90 min with a reaction temperature of 600C and alcohol seed ratio of 1:1 using the response surface methodology.  Initial catalyst concentration and reaction time were subjected to central composite experimental design of the response surface methodology.  Initial catalyst quantity and reaction time were found to have significant (P<0.05) effects on the yield of castor biodiesel produced, with increased catalyst quantity giving a negative effect on the yield after an initial amount of between 1.0 and 1.2%.  The reaction time had a positive effect on the yield until after 90 minutes after which biodiesel yield reduced with increased time. The CA-Time interactions influence was small and negative, due to the superior effect of initial catalyst quantity by the formation of by-products (soaps) leading to difficult ester separation from glycerol. A second-order model was obtained to predict the yield as a function of all factors. The model predicted well the observed data with a R2 value of 0.983. The biodiesel produced had properties comparable to the standards of ASTM while the specific gravity was higher than the specified standards

Characterization of Ajebo Clay in South West Nigeria

Ajebo clay deposit in Abeokuta, South West, Nigeria was characterized to establish its use industrially. The major properties investigated were drying and firing behaviour, apparent porosity, bulk density, water absorption capacity,, chemical compositions and X-ray diffraction. The qualitative analysis by inductively coupled plasma showed the mineral to be composed mainly of Aluminium, Oxygen and Silica, with low content of iron. The clay has modulus of rupture (strength) ranging from 15.04-35.62kgF/cm2 and the colour ranged from white brown to light red on firing. The properties signify that Ajebo clay is stoneware clay. It can be used for the production of stoneware, flowerpot, tiles and brick making

EFFECT OF TEMPERATURE AND PERCENTAGE OF INITIAL CATALYST ON THE IN-SITU PRODUCTION OF BIO-DIESEL FROM CASTOR OIL BEAN SEED USING RESPONSE SURFACE METHODOLOGY

The use of vegetable oil and animal fats for biodiesel production has recently become a great concern because of the competition with food materials.  As the demand for vegetable oil increase tremendously in recent years it has become impossible to justify the use of these oils for fuel production. In-situ trans-esterification process uses the oil (triglycerides) in the oil seed directly without the need for initial extraction as compared with the conventional trans-esterification. Castor oil bean seed contains between 35 and 55% oil and does not compete with food grade oil because of the seed’s toxicity. This study evaluated the effect of temperature and percentage of initial catalyst on yield of castor ethyl ester.  Raw castor oil bean seed kernel at moisture content of 4.68 % (db) was subjected to in-situ trans-esterification in a batch processor with ethanol as the solvent and sodium hydroxide as the catalyst.  Central composite design (CCD) of the Response surface methodology was applied to evaluate the main and interactive effects of initial catalyst amount (0.5 – 1.5%) and reaction temperature (40 – 70OC), on yield of castor ethyl-ester, at reaction time of 120 minutes and alcohol-seed weight ratio of 1:1.  A quadratic non-linear polynomial model was obtained to describe the effect of the factors on yield.  The model was significant (P< 0.05) with a non- significant Lack-of-Fit value (P< 0.05) and R2 value of 0.944. Second order response surfaces and contour plots obtained from the model revealed that initial catalyst amount was the more effective factors on yield while reaction temperature had less effect. The Temperature–percentage of initial catalyst interaction was small and negative, due to the combined effects of formation of by-products (soaps) and saponification. The biodiesel produced from ground castor oil bean seed during this study met the requirements of ASTM standard D6751-02 but specific gravity was higher than the ASTM standard confirming that biodiesel produced from castor bean seed using the in-situ technique can be used as replacement fuel for fossil diesel

Optimization of in-situ Biodiesel Production from Raw Castor Oil-Bean Seed

Optimization of in-situ biodiesel production from raw castor oil-bean seed was carried out from raw castor bean oil seed (37.9% oil content) by alkaline catalyzed in-situ trans-esterification with Sodium hydroxide as catalyst and ethanol as the solvent in a laboratory batch processor.  Response surface methodology and central composite experimental design was applied to evaluate effects of reaction time (30 -120 min), alcohol/seed weight ratio (0.5 – 2.0), Catalyst amount (0.3 – 1.5%) and reaction temperature (40 – 70OC).  Catalyst amount, reaction temperature and time all had significant main effects (p < 0.05) while Alcohol-seed ratio had only slight effects on yield of castor biodiesel as a main effect but was significantly involved in interactions with other factors.  A modified statistical model comprised of all significant factors and interactions (p < 0.05) obtained by multiple regressions predicted that the highest yield of castor ethyl-ester was 99.5% of expressible oil at the following optimized reaction values; alcohol/seed weight ratio of 0.5, a catalyst./seed weight ratio of 1.31, reaction temperature of 60.33oC, and reaction time of 81.7minutes.  A Taguchi L9(3^4)  optimization experimental design used to confirm the modified model at optimum point and two other points within experimental region produced yield that was significantly comparable to model predictions at 95% confidence level using  a paired t-test. Measured properties of the castor ethyl-ester such as viscosity(5.78mm2/s), pour point (-21.5 oC), flash point (177.12 oC), calorific value (47.76MJ/kg), acid value (0.34 mg KOH/g) and cetane number (48.73) were within the ASTM standard D6751-02 but specific gravity. Keywords: Castor oil-bean seed, biodiesel, in-situ trans-esterification, response surface methodology, optimization, Castor ethyl-este

Food quality profile of pounded yam and implications for yam breeding

Open Access ArticleBACKGROUND Assessment of the key preferred quality traits in pounded yam, a popularly consumed yam food product in West Africa, is often done through sensory evaluation. Such assessment is time-consuming and results may be biased. Therefore, there is a need to develop objective, high-throughput methods to predict the quality of consumer-preferred traits in pounded yam. This study focused on how key quality traits in pounded yam proposed to yam breeders were determined, measured by biophysical and biochemical methods, in order to shorten the breeding selection cycle through adoption of these methods by breeders. RESULTS Consumer tests and sensory quantitative descriptive analysis (QDA) validated that preferred priority quality traits in pounded yam were related to textural quality (smooth, stretchable, moldable, slightly sticky and moderately hard) and color (white, cream or light yellow). There were significant correlations between sensory textural quality attributes cohesiveness/moldability, hardness, and adhesiveness/stickiness, with textural quality measurements from instrumental texture profile analysis (TPA). Color measurement parameters (L*, a*, and b*) with chromameter agreed with that of sensory evaluation and can replace the sensory panel approach. The smoothness (R2 = 1.00), stickiness (R2 = 1.00), stretchability (R2 = 1.00), hardness (R2 = 0.99), and moldability (R2 = 0.53) of pounded yam samples can be predicted by the starch, amylose, and protein contents of yam tubers estimated by near-infrared spectroscopy. CONCLUSION TPA and Hunter colorimeter can be used as medium-high throughput methods to evaluate the textural quality and color of pounded yam in place of the sensory panelists

Design and performance evaluation of a cooler refrigerating system working with ozone friendly refrigerant

In this study, a cooler refrigerating system was designed, constructed and tested with various charge quantities of an ozone friendly hydro-fluorocarbon refrigerant (R134a) as working fluid. The results obtained showed that the design temperature and pull-down time set by International Standard Organisation (ISO) for small refrigerator were early achieved with refrigerant charges of 100 and 120 g than with 60 and 80 g charges. Approximately the same pull-down time and minimum temperature of -14°C were obtained with refrigerant charges of 100 and 120 g. Discharge pressure is about the same for 60, 80 and 100 g refrigerant charges, but significant increase in discharge pressure was observed as the refrigerant charge increased to 120 g. The rate of increase in the refrigerating capacity and the COP with respect to evaporator temperature for refrigerant charge of 60 g to 100 g are higher than that for refrigerant charge of 120 g. Highest refrigerating capacity and COP of 4.404 kW and 3.1, respectively, were obtained in the cooler refrigerator with 100 g charge. Generally, the best performance of the cooler was obtained with refrigerant charge of 100 g and increase in the charge beyond 100 g affected the performance of the cooler negatively

THE INFLUENCE OF INGOT GEOMETRY ON TEMPERATURE DISTRIBUTION IN HCSS316 DURING HOT ROLLING

The effects of material geometry on rolling parameters such as yield stress, rolling load and torque have been studied. In this work, geometrical variation is intruded into the Reverse Sandwich Rolling Model (RSM) for high carbon stainless steel type 316 (HCSS316). The modification affords evaluation of the possible effect of geometry of the in-going strip of HCSS316 on temperature distribution in the material during hot rolling. Simulation of the model was carried out using FORTRAN 77. The computer code was validated with hot rolling experimental data from two high-reversing hot rolling mills with different roll diameter. Results of the simulation revealed a symmetrical temperature distribution from the rolling surfaces, to the mid-thickness of the specimen where in peaked. Thos pattern was consistent for specimens with different geometry. The results showed agreement with experimental inferences

Influence of catalyst amount and alcohol-seed ratio on the production of bio-diesel from raw castor oil bean seed using in-situ technique

Trans-esterification is the most commonly used methods of biodiesel production. In-situ trans-esterification process uses oil (triglycerides) in seeds directly without the need for initial extraction. The in-situproduction of biodiesel from raw castor bean seed with a batch processor was studied at initial catalyst quantity of 0.1, 0.5 and 1.5%, reaction time of 30, 60 and 90 min with a reaction temperature of 600C and alcohol seed ratio of 1:1 using the response surface methodology. Initial catalyst concen-tration and reaction time were subjected to central composite experimental design of the response surface methodology. Initial catalyst quantity and reaction time were found to have significant (P<0.05) effects on the yield of castor biodiesel produced, with increased catalyst quantity giving a negative effect on the yield after an initial amount of between 1.0 and 1.2%. The reaction time had a positive effect on the yield until after 90 minutes after which biodiesel yield reduced with increased time. The CA-Time interactions influence was small and negative, due to the superior effect of initial catalyst quantity by the formation of by-products (soaps) leading to difficult ester separation from glyc-erol. A second-order model was obtained to predict the yield as a function of all factors. The model predicted well the observed data with a R2 value of 0.983. The biodiesel produced had properties com-parable to the standards of ASTM while the specific gravity was higher than the specified standard