Application of SSSC to the 330kV Nigerian transmission network for voltage control

Longitudinal power systems of Nigerian 330 kV transmission network have steady-state problems of congestion, voltage limit violation and high active power loss. Static Synchronous Series Compensator (SSSC) currently in use for solving problems in mesh power systems has not been applied to Nigerian 330 kV power network. This work involves the use of SSSC for solving problems associated with Nigerian 330 kV longitudinal power network using voltage magnitude as performance metrics. Steady state modeling of power system and SSSC modeling produced two sets of non-linear algebraic equations that were solved simultaneously using Newton-Raphson algorithm (NR) method and was implemented using MATLAB. Results of power flow analysis of Nigerian 330 kV transmission network without SSSC showed that, there was voltage limit violation of ±10% at bus 16 Gombe (0.8973p.u). However, the results with incorporation of SSSC showed that, the SSSC was effective in eliminating voltage limit violation, control bus voltage magnitude to specified value (bus 14 from 0.9462p.u. to 1.00p.u.) and reduced network active power loss by more than 5% of base case (93.87 MW). Therefore, SSSC is effective in solving steady-state problems of longitudinal power systems.Keywords: Longitudinal, Mesh, Newton-Raphson, SSSC modelin

Assessment of Quality of Asphalt Concrete used in Road Construction in South West Nigeria

Assessment of asphalt concrete used for pavement construction in southwest Nigeria was carried out to determine the causes of untimely failure of newly constructed/rehabilitated asphalt roads. Samples of asphalt concrete and bitumen were collected from three asphalt plants selected for the study. Samples from each plant were subjected to bitumen extraction and sieve analysis, hot mix Marshall Stability and flow tests, penetration and viscosity tests. Results obtained were compared to the 2007 Federal Ministry of Works and Housing Standard Specifications for Roads and Bridges. The results revealed that none of the samples met all the criteria stated in the specifications, suggesting that the nature of asphalt concrete is a possible cause of premature failure of road pavements in southwest Nigeria. It is recommended that further research be conducted on other constituents of asphalt concrete as well as other structures of the flexible pavement.Keywords: Asphalt concrete, aggregate, bitumen, pavement, road, sieve analysis

Comparison of the pre-treatment testosterone levels in benign prostatic hyperplasia and prostate cancer patients

Objectives: To compare serum testosterone and prostate specific antigen (PSA) levels of patients diagnosed of prostate cancer to those with benign prostatic hyperplasia (BPH).Subjects and methods: One hundred and thirteen male patients with or without LUTS who had indication(s) for prostate biopsies were recruited. Blood samples were analysed for serum testosterone and serum PSA. Prostate sizes were measured and PSA densities calculated before trans-rectal prostate biopsies were performed.Results: On histology of prostate biopsy specimens, 54 patients (47.8%) had prostate adenocarcinoma while 59 patients (52.2%) had BPH. Serum testosterone levels were lower in the prostate cancer group (23.09 ± 2.31 nmol/L versus 24.37 ± 1.94 nmol/L in the BPH group) but this difference was not statistically significant (p = 0.671). Serum testosterone also did not differ significantly with Gleason grade and Gleason score in patients with prostate cancer.Serum PSA and PSA density (PSAD) values were significantly higher in men with prostate cancer, and also in prostate cancer patients with high grade disease.Conclusion: Serum testosterone levels of patients with prostate cancer did not significantly differ from those of patients with BPH and were not related to grade in prostate cancer patients.Keywords: Serum testosterone; Prostate cancer; Benign prostatic hyperplasia; Serum prostate specific antige

Purification characterization and inhibition studies on Phospholipase C from Opisthacanthus capensis (Black Scorpion) venom

Phospholipase C from Opisthacanthus capensis venom was partially purified and characterized. The enzyme was purified 105.2 fold with an overall yield of 13% using various purification steps involving ammonium sulphate precipitation, protamine sulphate treatment, sephadex G-75  fractionation and DE-52 anion exchange chromatography. The purified enzyme was  homogeneous with a molecular weight of 29 kDa. The  phospholipase C has pH and temperature optima of 7.2 and 600C, respectively with activation energy of 25KJ/mol and t1/2 of 1.50 hr. Initial velocity studies on O. capensis venom phospholipase C revealed a KM of 0.02 mM and Vmax of 0.015 μmol/min. Studies on the effect of pH on KM and Vmax gave PKa1 of 6.9 and PKa2 of 7.4 with enthalpy of ionization of 20 KJ/mol suggesting  histidine in the active site. The enzyme was positively modulated by Mg2+, Zn2+ and Ca2+ and negatively by Fe2+. While Hg2+ produced complete inhibition. Various concentrations of leaf aqueous extract of Momordica charantia also inhibited the activity of O. capensis venom phospholipase C in vitro with a competitive pattern. This study revealed the presence of phospholipase C in O. capensis venom and gave some scientific basis for the use of theplant in the treatment of scorpion envenomation.Keywords: Phospholipase C; Opisthacanthus capensis;  Momordica charantia; Veno

Prevalence of clinical benign prostatic hyperplasia amongst community-dwelling men in a South-Western Nigerian rural setting: A cross-sectional study

Objectives: To determine the prevalence of benign prostatic hyperplasia (BPH) and correlates International Prostate Symptom Score (IPSS), peak/maximum flow rate (Qmax), quality of life (QoL) score and prostate volume (PV) amongst male adults in a rural setting in Nigeria.Subjects and methods: This is a community-based cross-sectional survey conducted amongst 615 men. Subjects selected using multi-staged sampling technique were interviewed for presence of lower urinary tract symptoms (LUTS) in their houses. Severity of symptoms was assessed using International Prostate Symptom Score (IPSS) questionnaire. Digital rectal examination (DRE), uroflowmetry and prostate scan were carried out in nearby primary health centres. Criteria for diagnosis of BPH were prostatic volume ≥ 30 cm3 with moderate/severe LUTS and/or Qmax < 15 mL. Relationships between variables were determined using Pearson’s Chi-squared and Fisher’s exact tests. Results: The overall prevalence of LUTS was 57.4% while 28.5% had moderate-to-severe IPSS with averagescore of 12.3 ± 5.2. More than half (56.1%) reported impaired QoL with average score of 3.4 ± 1.3. TheDRE and ultrasound prevalences of enlarged prostate were 68.3% and 64.9% respectively. About 29% hadabnormal Qmax. Both QoL and Qmax had significant relationship with IPSS (p < 0.001) while none existsbetween prostate size and IPSS (p = 0.339). The overall prevalence of BPH was 237 per 1000 men (23.7%).The age-specific prevalence rates increased from 104 per 1000 men in the fifth decade to 429 per 1000 in men >90 years.Conclusion: The burden of clinical BPH is very high amongst Nigerian men and the prevalence increaseswith age. There is need for more public awareness because of the significant impairment in the QoLassociated with BPH symptoms.Keywords: BPH; Community-dwelling men; IPSS; LUTS; Prevalenc

Historical context of ECOWAS intervention in the Gambian constitutional crisis; USSR in World War II (1939-1945)

The Gambian constitutional crisis that followed the controversial presidential elections of December 2016 may have been put to rest, however, the lessons learnt, the role of ECOWAS in mitigating the impasses and the controversial nature of the intervention continues to be a topical theme among historians and scholars of international relations. The sanctioning of the peace operation by both the UN Security Council and the African Union (AU) legitimizes it, the peaceful outcome further allows us to adjudge the mission as justifiable and recommend it as a means of entrenching and protecting democracy in Africa. © 2019 Rossiiskaya Akademiya Nauk, Institut Istorii (Russian Academy of Sciences, Institute of General Hist. All rights reserved

Influence of environment on protein and oil contents of soybeans seed (Glycine Max (L.) Merril)

An attempt was made to study the magnitude of environmental variability on protein and oil contents of six genetically diverse soybean genotypes under three environments represented by three locations in Nigeria (Zaria in Northern Guinea Savanna, Jos in Pseudo Savanna and Mokwa in Southern Savanna) for two years (1996 and 1997). Significant genotypic location and location x genotype x year effects were observed for protein content while genotypic and location x genotype effects were significant for oil contents. Significant genetic differences in protein content occurred among genotypes, locations and between years, whereas significant genotypic differences in oil content was observed. Bossier and TGX849-313D out yielded in protein content. Protein content in Mokwa and Zaria were higher than that of Jos while protein content in Year 2 (1997) was higher than Year 1 (1996). Oil content remained similar irrespective of location and year. Jos is in a dry cool environment compared with Mokwa which is humid and hot and Zaria which is dry and hot. Environmental factors exerted greater influence more on the protein content than oil content of tropical soybean seeds. High temperature tended to increase protein content with little or no effect on oil content. There was positive significant association between protein and oil contents under Jos environment in 1997 whereas the association was negatively significant under Mokwa environment. Therefore, selection for protein and oil contents among soybean genotypes for further improvement is possible due to large variability present. Variations in protein and oil contents were due to differences in location. Changes in climatic factors resulting from yearly cultivation of soybean in different locations can influence protein content. Key Words: correlation analysis, genotype, Glycine max, oil, protein [Global Jnl Agric Sci Vol.1(1) 2002: 27-32

Comparative evaluation of organomineral fertilizer and NPK 151515 on growyh and yield of cassava varieties in Ibadan, southwestern Nigeria

Field experiments were conducted at Ajibode area in Ibadan to investigate the effects of organomineral fertilizer (OF) and NPK fertilizer treatments on the growth and yield of two cassava varieties: TMS 30572 and TMS 92/0326. Five rates of OF (1.5, 2.5, 3.5, 4.5, 6.0 t/ha), NPK 15:15:15 at 600 kg/ha and control (no fertilizer) treatments (subplots) were valuated on cassava (main plot) which was planted at 10,000 plants per hectare. Treatments were assigned using a split plot arrangement in a randomized complete block design with three replicates. Parameters assessed include plant height, number of leaves, leaf area index (LAI) fresh and dry root yield (DRY). Data were analyzed using ANOVA at p < 0.05. Mean LAI at 6 MAP (2.86 and 2.21), fresh and DRY (at harvest) of 32.2 and 12.3 t/ha obtained for TMS 92/0326 were significantly higher than that of TMS 30572 (26.6 and 9.5t/ha), respectively. Fresh root yields at 12 MAP harvest obtained with various fertilizer treatments were in the order: 35.3 > 33.0 > 32.5 > 31.2 > 30.9 > 26.1 > 20.2 t/ha for 6.0 t OF/ha, NPK at 600 kg\ha, 4.5, 2.5, 3.5, 1.5 t OF/ha and control, respectively. Optimum yield of cassava root was obtained with application of 2.5 t OF/ha, similar to that obtained in NPK treatment, thus making OF a good substitute for mineral fertilizer