Synchrotron-based pore-network modeling of two-phase flow in Nubian Sandstone and implications for capillary trapping of carbon dioxide

Depleted oil fields in the Gulf of Suez (Egypt) can serve as geothermal reservoirs for power generation using a CO2-Plume Geothermal (CPG) system, while geologically sequestering CO2. This entails the injection of a substantial amount of CO2 into the highly permeable brine-saturated Nubian Sandstone. Numerical models of two-phase flow processes are indispensable for predicting the CO2-plume migration at a representative geological scale. Such models require reliable constitutive relationships, including relative permeability and capillary pressure curves. In this study, quasi-static pore-network modelling has been used to simulate the equilibrium positions of fluid-fluid interfaces, and thus determine the capillary pressure and relative permeability curves. Three-dimensional images with a voxel size of 0.65 micro m3 of a Nubian Sandstone rock sample have been obtained using Synchrotron Radiation X-ray Tomographic Microscopy. From the images, topological properties of pores/throats were constructed. Using a pore-network model, we performed a sequential primary drainage-main imbibition cycle of quasi-static invasion in order to quantify (1) the CO2 and brine relative permeability curves, (2) the effect of initial wetting-phase saturation (i.e. the saturation at the point of reversal from drainage to imbibition) on the residual-trapping potential, and (3) study the relative permeability-saturation hysteresis. The results improve our understanding of the potential magnitude of capillary trapping in Nubian Sandstone, essential for future field-scale simulations. Further, an initial basin-scale assessment of CO2 storage capacity, which incorporates capillary trapping, yields a range of 14-49 GtCO2 in Nubian Sandstone, Gulf of Suez Basin

Comparative evaluation of processes for production of soybean meal for poultry feed in Nigeria Evaluación comparativa de procesos para la producción de harina de soya para la alimentación de pollos en Nigeria

This work examined and compared three processes for production of low trypsin inhibitor soybean meal. Soybean flour was subjected to roasting, autoclaving and steaming to denature trypsin inhibitors. Roasting was done at 120, 130, 135 and 140 ºC for 5, 7, 8 and 9 minutes, respectively. Autoclaving was carried out at 121ºC, 15psig for 20, 30, 40 and 50 minutes. Steaming was carried out at 105 ºC for 10, 12, 15 and 18 minutes. Defatting of the samples was done and the activity of trypsin inhibitor was investigated. Proximate analysis and quality tests was carried out to ascertain quality of the heat treated soybean meals. Trypsin inhibitor in the soybean meals from the three heat treatment processes ranged from 1.20 to 3.54mg/g while that of raw sample was 6.01mg/g. Percentage crude protein in all the heat treated samples ranged from 39.38 to 40.58 % while that of raw sample was 44.60 %. Urease index ranged from 0.11 to 2.07 % for all heat treated samples while it was 2.11 % for the raw samples. % KOH protein solubility in Soybean meal from the three processes ranged from 45.2 to 73.1 % while that of the raw sample was 49.1%. The results were statistically significant at p>0.05. At significance level of p>0.05 it was established that local soybeans can be processed with adequate heat to obtain low activity soybean meal with good nutrient standard. The steaming process operated at 105 ºC for 18 minutes gave the best overall results with trypsin inhibitor activity of 1.20 mg/g

Obstetric analgesia for vaginal birth in contemporary obstetrics: a survey of the practice of obstetricians in Nigeria

BACKGROUND: Contemporary obstetrics in sub-Saharan Africa is yet to meet the analgesic needs of most women during child birth for a satisfactory birth experience and expectedly, obstetricians have a major role to play in achieving this. METHODS: This was a questionnaire-based, cross-sectional study of 151 obstetricians and gynecologists that attended the 46th Annual General Meeting and Scientific Conference of the Society of Gynaecology and Obstetrics of Nigeria (SOGON) held in Abakaliki, southeast Nigeria in November, 2012. SOGON is the umbrella body that oversees the obstetric and gynecological practice in Nigeria. Data was collated and analyzed with Epi-info statistical software, and conclusions were drawn by means of simple percentages and inferential statistics using Odds Ratio, with P-value < 0.05 at 95% Confidence Interval (CI) taken to be statistically significant. RESULTS: Of the 151 participants, males predominated; 110 (72.9%) practiced in government-owned tertiary hospitals in urban locations. Only 74 (49%) offered obstetric analgesia. Among users, only 20 (13.3%) offered obstetric analgesia routinely to parturients, 44 (29.1%) sometimes and 10 (6.6%) on patients’ requests. The commonest analgesia was opioids (41.1%). Among non-users, the commonest reasons adduced were fear of respiratory distress (31.1%), cost (24.7%) and late presentation in labour (15.6%). CONCLUSION: The routine prescription and utilization of obstetric analgesia by obstetricians in Nigeria is still low. Obstetricians are encouraged to step up its use to make childbirth a more fulfilling experience for parturients

Potential Impact of Cypermethrin on Selected Groups of Soil Microorganisms

Application of cypermethrin as insecticide during agricultural practices is a global concern due to its toxicity and potential accumulation of its metabolites in the aquatic environment. A mesocosm plot of agricultural land (500 m2) was demarcated and deliberately contaminated with cypermethrin to study its impact on the autochthonous microorganisms. Potential effects of 3- phenoxybenzoic acid (3-PBA), a known suicide metabolite of cypermethrin, on hydrolytic activities were also investigated by using fluorescein diacetate assay (FDA). A significant increase in the abundance of total heterotrophic bacteria from 3.55 x 106cfu g-1to 1.30 x 108cfu g-1in 12 weeks as against the control was induced by the insecticide in the mesocosm. The number of starch hydrolysing bacteria increased after the second insecticide treatment from 6.25 x 106cfu g-1to 2.70 x 107 cfu g-1in three weeks. However, there was no significant increase in the microbial count of fungi, presumptive actinomycetes and nitrogen fixing bacteria during the twelve weeks of experiment. The hydrolytic activity of soil microorganisms was apparently inhibited insoil treated with different concentration of 3-PBAthan in untreated soil. These results suggest that the application of a commercial cypermethrin formulation increased the abundance of selected soil microorganisms while3- PBA reduced the soil microbial hydrolytic activity

Modelling the power output from a steam power plant in Nigeria

Adequate supply of electricity at a competitive price is pivotal to sustainable development. More often than not, the generation of electricity which drives modern growth and development is currently powered by limited fossil fuels in many nations. Electricity generation and megawatt demand are also usually fluctuating due to several pertinent factors. In a bid to articulate the impact of inherent variations in process parameters on the performance of steam power plant at different loads, this paper presents an investigation into the efficacy of two validation strategies in predicting the net power output from the plant using GMDH Shell software. Using the combinatorial algorithm, the k-fold cross-validation strategy and the training/testing validation technique were applied to empirical data of a power plant in Nigeria. The performance of the models returned from the two validation strategies was evaluated using maximum negative error, maximum positive error, mean absolute percentage error (MAPE), root mean square percentage error (RMSPE), residual sum, the standard deviation of residuals, coefficient of determination (R2) and correlation. For the number of folds and the training/testing split percentage considered in this study, results show that both models obtained were quite competitive, with the k-fold model having a slight edge over the other model. It is expected that the outcome of the study will be handy in researches for providing knowledge base information on choosing and setting optimum operating conditions at various load demand

Cashew nut testa tannin resin – preparation, characterization and adsorption studies

Adsorption of metal ions and dyes from water by cashew nut testa tannin resin (CATAR) was studied and the effects of temperature, initial pH, initial concentration and time were investigated. Scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) reveal effective adsorption processes. Kinetic studies show that CATAR adsorption is complex and thermodynamic parameters calculated reveal spontaneous and endothermic adsorption of studied pollutants onto CATAR. The use of CATAR as an alternative adsorbent is proposed considering that of simulated wastewaters gave excellent removal performances of 94.0% (Cd ions), 99.4% (Cu ions) and 97.1% (Pb ions) at pH of 6 and 303 K using amount of CATAR. Removal performances obtained for simulated dye wastewaters using CATAR at similar conditions for removal of metal ions gave 71.1%, 79.2% and 86.6%, respectively for crystal violet, methylene blue and malachite green

Challenges and opportunities in the design and construction of a GIS-based emission inventory infrastructure for the Niger Delta region of Nigeria

© 2017, Springer-Verlag Berlin Heidelberg. Environmental monitoring in middle- and low-income countries is hampered by many factors which include enactment and enforcement of legislations; deficiencies in environmental data reporting and documentation; inconsistent, incomplete and unverifiable data; a lack of access to data; and technical expertise. This paper describes the processes undertaken and the major challenges encountered in the construction of the first Niger Delta Emission Inventory (NDEI) for criteria air pollutants and CO2 released from the anthropogenic activities in the region. This study focused on using publicly available government and research data. The NDEI has been designed to provide a Geographic Information System-based component of an air quality and carbon management framework. The NDEI infrastructure was designed and constructed at 1-, 10- and 20-km grid resolutions for point, line and area sources using industry standard processes and emission factors derived from activities similar to those in the Niger Delta. Due to inadequate, incomplete, potentially inaccurate and unavailable data, the infrastructure was populated with data based on a series of best possible assumptions for key emission sources. This produces outputs with variable levels of certainty, which also highlights the critical challenges in the estimation of emissions from a developing country. However, the infrastructure is functional and has the ability to produce spatially resolved emission estimates

Permanence, Temporality and the Rhythms of Life : Exploring Significance of the Village Arena in Igbo Culture

The village arena (or ‘square’ or ‘Otobo’ in Nsukka Igbo) is at the physical and socio-cultural centre of Igbo life, in southeast Nigeria. It is a space where intangible Igbo cultural heritage is played out, and also serves as a virtual museum where heritage materials are kept. The arena performs its roles in two very different ways: as a sacred space hosting initiation rites and religious rituals; and as a profane space for meetings and ceremonies. Either way, these uses see the arena transition between permanency and temporality, following routines and rhythms which themselves give the practices meaning and significance, and contribute to their inscription on the landscape. This paper explores the complexities associated with these village arenas with a particular focus on their socio-cultural, political, economic and religious functions through time, as well as the way those complexities are manifest in material cultures that serve to characterize the village arena