Prediction of Efficiency for a Passive Flat Plate Collector for Water Desalination using Artificial Neural Network

Artificial neural network was used for modeling and prediction of the efficiency of a  passive flat plate collector for water desalination. An extensive experimental program design was undertaken on the collector to obtain the parameters required for the modeling. The neural model to predict the efficiency was developed based on groups of experiments carried out. Five (5) parameters: ambient, inlet fluid and outlet fluid temperatures, radiation, and aperture area of the collector were used as inputs into the network architecture of 5 [5]1 1 in predicting the efficiency. After series of network architectures were trained using different training algorithms such as Levenberg-Marquardt, Bayesian Regulation, Resilient Backpropagation using MATLAB 7.9.0 (R20096), the LM 5 [5]1 1 was selected as the most appropriate model. Prediction of the neural model exhibited reasonable correlation with the experimental collector efficiency. The predicted collector efficiency gave minimal MSE errors and higher correlation coefficients and Nash-Scutcliffe efficiency (NSE) indicating that the model was robust for predicting the efficiency of a passive flat plate collector for desalination of water. Keywords: Collector efficiency, desalination, passive solar collector, artificial neural network, Nash-Scutcliffe efficiency, MSE error, modeling

Total Thermal Energy Conservation Strategy during the Utilization of a Common Charcoal Stove

The proliferation and use of charcoal stoves is on the increase even in urban locations in Nigeria despite the environmental hazard associated with charcoal production. The rising cost of fossil fuel, smokeless nature of charcoal combustion and probably inexistent or ineffective legislation(s) against deforestation could be the reasons for this. This study aims at more efficient use of the energy available from the use of common charcoal stoves. A common slightly improved charcoal stove was placed in an enclosure with openings for air inflow and heating of the pot, and linked to a heat receiver through duct all of burnt brick. The stove enclosure, heat receiver inlet and outlet, and the ambient temperatures were measured during boiling of water for 3 periods/stages of 22 minutes per day for 6 days. The quantity of heat generated in the enclosure, the percentage reaching the heat receiver and the total heat losses from the system were computed under steady state conditions. A mean value of 93.85 kJ/kg of air was generated in the enclosure with about 34.33% reaching the heat receiver. The mean temperature within the heat receiver was 70.40C and the mean total heat loss from the system was about 6.4 kJ/kg of air. This strongly indicates great potentials for utilizing part of the thermal energy generated from the use of charcoal stoves for cooking for other alternative uses such as drying and other forms of preservation of foodstuff thereby improving their utilization efficiency and probably compensating in part for the adverse effect on the environment as a result of sustained charcoal production. Keywords: Charcoal, thermal energy, energy conservation, energy utilization efficiency, stove, environmental hazar

CONTENT AND COMPOSITION OF LIPID PRODUCED BY CHLORELLA VULGARIS FOR BIODIESEL PRODUCTION

This study aims at investigating the lipid profile of Chlorella vulgaris to determine its suitability as an alternative bio-fuel source. Chlorella vulgaris (stock culture UTEX 259) was sub-cultured at laboratory scale. The cells were kept in 250ml, 500ml, and 1000ml Erlenmeyer flasks with 200ml, 300ml, and 600ml of medium respectively and shaken occasionally in Bold Basal Medium with initial pH value 7 at the temperature of 22+ 30c with constant light intensity for the culture medium which was not more than 2500 lux on a 16:8 light to dark cycle for 7 weeks. The Chlorella vulgaris cells were harvested and the oil extracted. The percentage lipid content was determined by soxhlet extraction and was shown to be 25%. The GC-MS analysis of the transesterified oil showed this lipid profile; nonanoic acid, decanoic acid, palmiltic acid, stearic acid ,oleic acid, linoleic acid with this  chain length C9:0,10:0,16:0,18:0,18:1,18:2 respectively. The percentage unsaturated fatty acid for nitrogen rich media and nitrogen deprived media were 79.22% and 74.2% respectively while the percentage saturated fatty acids were 20.2% and 25.8% respectively. This study shows that Chlorella vulgaris is a suitable candidate for biodiesel production because the lipid profile, lipid composition and level of unsaturation meets requirement of oil suitable for biodiesel production. Key words: Chlorella vulgaris , lipids, oleic acid ,bio-fuel

The Impact of Human Encroachment and River Bank Agricultural Activities on the Habitat of the Manatee (Trichechus Senegalensis) Along the Lower Benue River, Benue State, Nigeria

The impact of human encroachment and river bank Agricultural activities on the habitat of the manatee (Trichechus Senegalensis) was investigated. The method of data collection involved the use of a structured questionnaire administered to farmers and fishermen. Vegetation survey in three selected sites along the river was carried out during the dry and raining seasons and crops cultivated during these seasons were identified. Chemicals used by farmers, measurement of settlements and farms from the river bank as well as the population trends in the selected zones were investigated. The result was subjected to descriptive and inferential statistics. Nine different vegetable crops were cultivated in Makurdi over an area of 16.974 ha, while 3 crops were cultivated in Abinsi (11.2076 ha) and 2 in Gbajimba (6.8775 ha). Plant diversity in Makurdi during the dry season is (0.1322), Abinsi (0.795) and Gbajimba (0.0568) while Abinsi had a diversity of 0.3281 Makurdi 0.2524 and Gbajimba 0.1749, during the raining season. Correlation coefficient (r) shows a significant relationship (p>0.05) between plants during the dry and rainy period in all the three zones. There is massive use of chemicals during the dry season farming while there is an increased activity of sharp sand collection along the river

Effect of solvents on the synthesis of hydroxyapatite sodium alginate nanocomposites for doxorubicin drug loading and delivery

In situ preparation of hydroxyapatite-sodium alginate nanocomposite (HASA) was carried out by the wet chemical precipitation method using water, ethanol, ethyl acetate and acetone as the dissolution medium. Drug loading was carried out at neutral pH, while in vitro drug release study was carried out in synthetic body fluid (SBF) at pH 7.4 and 37 oC.  The FTIR results show similar functional groups for precursors and synthesized nanocomposites. The nanocomposite prepared in water medium has the highest drug encapsulation efficiency of 83.67 %. Doxorubicin release profile comparison using difference factor (f1), showed that there is no significant difference between release profile of doxorubicin from nanocomposite synthesized in acetone and ethyl acetate ((f1 = 3.92), while other release profiles differed significantly. All the formulations follow first order release rate, while the n exponent in the Korsmeyer-Peppas equation indicates that the release mechanism is dominated by Fickian diffusion. The release profiles also indicate that nanocomposites synthesized from water medium is a better delivering agent for doxorubicin than the nanocomposites from the others solvents. Keywords: nanocomposites, solvents, drug loading, hydroxyapatite, release profil

Multivariate analysis of the physico-chemical properties of soils in selected locations of the floodplain of river Kaduna in Niger state, Nigeria

Multivariate statistics was used to analyse the physico-chemical properties of soil in the selected locations of the floodplain of River Kaduna in Niger State, Nigeria. Samples were collected in March and September of the same year and the levels of some important soil quality parameters analysed. The data was subjected to basic statistics, cluster analysis (CA), Principal Component Analysis (PCA), Correlation Analysis, and Discriminant Analysis (DA). Descriptive statistics shows that, with the exception of silt and clay other parameters analysed decreased in value after flooding, while the predominant textual class of the soil is clay-loam. The PCA for March and September sampling periods extracted three components each which explained 84.10% and 78.90% respectively of the total variance. Cluster analysis yielded five distinct clusters for March: cluster 1 (K, Ca, EA, and pH); cluster 2 (OM, CEC, TN, Silt content, Clay content, and OC); cluster 3 (Na); cluster 4 (P), and cluster 5 (Mg and Sand content); and five separate clusters for September. From DA, seven variables (pH, OC, OM, TN, P, K and Mg) were the most significant parameters which accounted for the expected spatial/temporal variations in the soil of March, while CEC, Na, Ca, silt, sand and clay become an important discriminator in September. Flood has significant influence on the soil of the study area as level and distribution of the parameters changed from March to September

A Comparative Study of Biogas Yield from Various Brewery Wastes and Their Blends with Yam Peels

A study was undertaken to determine biogas yield (% methane) from various local brewery wastes and their blends with yam peels (YP). The wastes investigated were Kunu chaff (KC), Burukutu (BKT) and spent grain (SG). The wastes were in two blends A and B. The blend A was SG:BKT:KC = 40:30:30 and blend B was SG:BKT:KC:YP = 40:20:20:20. All the waste types and their blends were bio-digested in an anaerobic digester in replicates for 20 days at ambient temperature experiment. The N, TS, VS, C, C:N, pH of the feedstocks were determined by standard methods. The gas yield was obtained by downward displacement of water. ANOVA at p ≤ 0.05 was used to determine if there was any significant difference in the biogas yield from the waste types. The gas yield were of the order blend B > KC > blend A > SG > BKT > YP. Blend B which had the highest yield of 75.6% had the highest C:N of 27;1 while YP which had the least of yield 52.3% had the least C:N of 10:1.The results obtained indicate good prospects for generation of biogas while managing the wastes generated from various brewing activities in Nigeria both for small- and large-scale applications. Keywords: Comparative, biogas, local brewery wastes, anaerobic digester, spent grain, yam peels, blends

Use of water quality index to assess the impact of flooding on water quality of River Kaduna, Nigeria

Flooding is increasingly becoming a yearly occurrence in Nigeria and many parts of the world and is linked to climate change. It comes with a wide range of consequences including the destruction of life and property and surface water pollution. This study used water quality index (WQI) to assess the impact of 2019 and 2020 flood events on the water quality of River Kaduna. Nine water quality parameters were selected based on Nigeria standards, while the weighted arithmetic method was applied in calculating the WQI. The result shows that electrical conductivity, TDS, Cl-, Na, sulphate, and nitrate were all below the maximum standard limits throughout the study period, while Fe and turbidity were above the limits. While other parameters showed varied responses before and after the two flood events, Fe and turbidity were consistently higher after the flood events. The water quality of the river is generally in the extremely poor class, both before and after the 2019 and 2020 floods (WQI > 100). There was a pronounced decrease in water quality at all the sampling stations after both the 2019 and 2020 flood events. The decreasing water quality should be of a public health concern as a large number of people depends on this river for domestic use

EFFECTS OF METAL INERT GAS WELDING PARAMETERS ON SOME MECHANICAL PROPERTIES OF AUSTENITIC STAINLESS STEEL IN ACIDIC ENVIRONMENT

The purpose of the present study is to investigate the effects of metal inert gas (MIG) welding parameters on the mechanical properties (hardness, tensile and impact) of type 304 austenitic stainless steel (ASS) immersed in 0.5M hydrochloric acid at ambient temperature. The MIG welding was applied to 3mm thick ASS. The dimensions of the samples were 50mm x 15mm x 3mm and 120mm x 15mm x 3mm rectangular bars each for impact, hardness and tensile tests and for immersion in the medium. Design Expert Software, Scanning Electron Microscopy (SEM), Rockwell Hardness Test, Monsanto Tensometer and Izod Impact Test were used to determine the interactions of parameters, microstructural analysis and optimal performances of the parameters respectively. Experimental results indicate that tensile strength increased with increase in welding parameters from 120MN/m2 to 133MN/m2 at speed of 40cm/min and current of 110. when the properties are compared with varying weld parameters adopted in joint’s weld operations, there was a pattern displayed among the weld parameters with C3 (19.7HRA, 203N/mm2 and 19.7J )and C4 (14.9 HRA, 189N/mm2 and 14.9J) consistently coming out as the parameter producing an ASS weld joint with the best mechanical properties of hardness, tensile and impact strength. Surface corrosion deposit composition was analyzed with the SEM paired with energy dispersive spectrometer (EDS) to ascertain microstructural behavior of the material.   http://dx.doi.org/10.4314/njt.v36i3.2