Multi criteria risk analysis of a subsea BOP system

The Subsea blowout preventer (BOP) which is latched to a subsea wellhead is one of several barriers in the well to prevent kicks and blowouts and it is the most important and critical equipment, as it becomes the last line of protection against blowout. The BOP system used in Subsea drilling operations is considered a Safety – Critical System, with a high severity consequence following its failure. Following past offshore blowout incidents such as the most recent Macondo in the Gulf of Mexico, there have been investigations, research, and improvements sought for improved understanding of the BOP system and its operation. This informs the need for a systematic re-evaluation of the Subsea BOP system to understand its associated risk and reliability and identify critical areas/aspects/components. Different risk analysis techniques were surveyed and the Failure modes effect and criticality analysis (FMECA) selected to be used to drive the study in this thesis. This is due to it being a simple proven cost effective process that can add value to the understanding of the behaviours and properties of a system, component, software, function or other. The output of the FMECA can be used to inform or support other key engineering tasks such as redesigning, enhanced qualification and testing activity or maintenance for greater inherent reliability and reduced risk potential. This thesis underscores the application of the FMECA technique to critique associated risk of the Subsea BOP system. System Functional diagrams was developed with boundaries defined, a FMECA were carried out and an initial select list of critical component failure modes identified. The limitations surrounding the confidence of the FMECA failure modes ranking outcome based on Risk priority number (RPN) is presented and potential variations in risk interpretation are discussed. The main contribution in this thesis is an innovative framework utilising Multicriteria decision making (MCDA) analysis techniques with consideration of fuzzy interval data is applied to the Subsea BOP system critical failure modes from the FMECA analysis. It utilised nine criticality assessment criteria deduced from expert consultation to obtain a more reliable ranking of failure modes. The MCDA techniques applied includes the technique for order of Preference for similarity to the Ideal Solution (TOPSIS), Fuzzy TOPSIS, TOPSIS with interval data, and Preference Ranking Organization Method for Enrichment of Evaluations (PROMETHEE). The outcome of the Multi-criteria analysis of the BOP system clearly shows failures of the Wellhead connector, LMRP hydraulic connector and Control system related failure as the Top 3 most critical failure with respect to a well control. The critical failure mode and components outcome from the analysis in this thesis is validated using failure data from industry database and a sensitivity analysis carried out. The importance of maintenance, testing and redundancy to the BOP system criticality was established by the sensitivity analysis. The potential for MCDA to be used for more specific analysis of criteria for a technology was demonstrated. Improper maintenance, inspection, testing (functional and pressure) are critical to the BOP system performance and sustenance of a high reliability level. Material selection and performance of components (seals, flanges, packers, bolts, mechanical body housings) relative to use environment and operational conditions is fundamental to avoiding failure mechanisms occurrence. Also worthy of notice is the contribution of personnel and organisations (by way of procedures to robustness and verification structure to ensure standard expected practices/rules are followed) to failures as seen in the root cause discussion. OEMs, operators and drilling contractors to periodically review operation scenarios relative to BOP system product design through the use of a Failure reporting analysis and corrective action system. This can improve design of monitoring systems, informs requirement for re-qualification of technology and/or next generation designs. Operations personnel are to correctly log in failures in these systems, and responsible Authority to ensure root cause analysis is done to uncover underlying issue initiating and driving failures

An Insight into the Explored and the Unexplored Aspects of Vision Rehabilitation in Nigeria: A Systematic Review of Literature

Purpose: There is paucity of research on rehabilitation of visually impaired persons in Nigeria. A myriad of gap in knowledge exist in what rehabilitation options are available, priority areas for rehabilitation, as well as important themes in rehabilitation research. Thus, the aim of the review is to highlight predominant areas of research concern and consequently, reflect and discuss the neglected aspects of vision rehabilitation.Methods: The following databases were accessed: Medline PubMed, CINAHL, Cochrane Databases of Systematic reviews, Web of Science, AFROLIB, SCOPUS, Embase, EBSCO Africa-wide Information, and MEDLIB. Other databases accessed incclude Google Scholar, Google, and African Journals Online (AJOL).Keywords used included: Visual impairment, low vision rehabilitation in Nigeria, visual disability, blindness, rehabilitation of blind, vision rehabilitation, visual rehabilitation in Nigeria, adaptation to visual impairment.Results: From the accessible databases, 87 articles related to rehabilitation of people with blindness and low vision in Nigeria were found; of these, only 16 articles met the inclusion criteria set for this review (vision rehabilitation studies conducted between 2000 and 2018). The findings reveal that much of the research on vision rehabilitation in Nigeria focused mainly on vocational and formal education rehabilitation to enhance opportunities for paid employment, independence and stakeholders involvement.Conclusion: Research on the emotional needs of visually impaired individuals is scarce and relatively given litile or no attention. Vision care practitioners and researchers need to pay special attention to the emotional rehabilitation needs of visually impaired persons.Keywords: Visual disability, blindness, rehabilitation of blind, vision rehabilitation, visual rehabilitation in Nigeria

Comparative study of some enzymes in different varieties of fruits

Arginase, rhodanese and thiaminase are enzymes often encountered and that play crucial roles in different metabolic pathways. These enzymes were found to be present in different fruits: avocado pear (Persea americana), water melon (Citrullu slanatus), green exotic apple (Malus domestica), red exotic apple (Malus pumila), red local apple (Syzygium malaccense); pink local apple (Syzygium samarangense); sweet orange (Citrus sinensis), tangerine (Citrus tangerina), lime (Citrus aurantifolia), pawpaw (Carica papaya), banana (Musa acuminata), pineapple (Ananas comosus) and grape (Citrus paradisi). It was found that avocado pear has highest activity of arginase, rhodanese and thiaminase than the rest of the fruits  investigated. The specific activity of rhodanese was however highest in water melon while that of arginase was more or less the same in red local apple and avocado pear. Arginase was also seen to vary significantly in the different plant samples with orange having the highest mean value of activity while sweet potato showed no activity. The study provides   information on the presence of thiaminase, arginase and rhodanese in the different plants for nutritional purpose.Keywords: Enzymes, arginase, rhodanese, thiaminase, fruits

Isolation and kinetic properties of arginase in the gut of grasshopper (Zonocerus variegatus Linn)

Arginase (EC 3.5.3.1) catalyzes the hydrolysis of arginine to ornithine and urea. Arginase was purified and characterized from the gut of Zonocerus variegatus through DEAE-cellulose and biogel-P100 gel filtration chromatography. The specific activity of the enzyme was 3.7 μmoles/min  per mg of protein and a yield of 14.7%. An apparent molecular weight of 143,000 daltons was estimated by gel filtration on biogel P-100. The Michaelis constant (Km) of the enzyme was 40 mM with arginine as substrate. The optimum pH was 8.0 and the optimum temperature was 40 oC for Z. variegatus arginase. The enzyme was stable up to 40 oC for 20 min and lost all of its activity at 80 oC. The enzyme was specific for arginine as substrate. The enzyme was strongly enhanced in the presence of Mn2+, Na+, NH4 + and Hg2+ showed similar activation. Ni2+ and Zn2+ slightly inhibited Z. variegatus. Chelating (EDTA, citrate, ascorbic acid and urea) and thio (2-mercaptoethanol and cystein) compounds inhibited the activity of arginase in Z. variegatus. While amino acids (proline, lysine, aspartate and valine) showed no inhibition on arginase activity. The presence of arginase in the gut of Zonocerus variegatus could be for other functions rather than urea production in urea cycle. © 2013 International Formulae Group. All rights reserved. Keywords: Arginase; Zonocerus variegatus; Distribution; Physicochemical Properties

Effects of culture systems on growth and economic performance of Oreochromis niloticus (Linnaeus, 1758) in concrete tanks

The effect of culture system on growth and economics performance of Orechromis niloticus (Nile tilapia) in concrete tanks was investigated. Four outdoor concrete tanks measuring 2.5 x 2 m was used for the study for 24 weeks culture period. The culture systems included the use of algae only at the stocking rates of 4 fishes/m2 (T1), algae plus commercial feed at the stocking rate of 10 fishes/m2 (T2), and commercial feed only at the stocking rate of 20 fishes/m2 (T3). The tanks were stocked with O. niloticus fingerlings with mean weight of 1.160, 1.030 and 0.255 g for T1, T2 and T3, respectively. Each treatment was replicated twice. Data collected were analyzed using analysis of variance and mean comparison was carried out using Duncan Multiple Range Test (DMRT). All tests were carried out at 5% probability level. The result on growth performance show that the intensive system (T1) was significantly different in some growth parameters (P < 0.05) such as yield (0.115, 0.830 and 1.260 kg/m3 for T1, T2 and T3, respectively), specific growth (1.975, 2.750 and 3.425% for T1, T2 and T3, respectively), survival rate (90, 80 and 91% for T1, T2 and T3, respectively), and feed conversion ratio (1.150 and1.030 for T2 and T3, respectively). Economically, the intensive system was more profitable with a gross margin of N 122, which was 40% more profitable than the extensive system (T1 with Gross margin of N 80), and 269% than commercial feed plus algae (T2 with Gross margin of – N 194). The cost of production (incidence of cost) showed that it cost more (N 447) to produce O. niloticus using commercial feed plus algae (T2) in concrete tank than the use of algae only (T1) (N 268) and the use of commercial feed only (T3) (N380).Keywords: Culture system, growth performance, economic performance, Oreochromic niloticusAfrican Journal of Biotechnology Vol. 12(27), pp. 4374-437

Serum iron and total iron binding capacity levels among the abo blood groups in Enugu, south eastern Nigeria.

Iron deficiency anaemia is a common tropical disease. Iron plays a very important role in the human body. The understanding of the different blood groups ability to retain iron in their system can give an insight into their ability to handle the disease Iron deficiency anaemia. Serum Iron, Total Iron Binding Capacity (TIBC) and Percentage Transferrin Saturation (%TS) levels were studied in 2260 apparently healthy Nigerian volunteers in Enugu, Eastern Nigeria. The ABO blood groups of the subjects were also determined. They were aged between 10 and 25 years, males were 1808 and females 452 (M/F ratio- 8:2).In all the results obtained, the females had lower values. Serum iron (micromol/L) was highest in the group A (26.3 +- 7.2 - males, 18.7 +- 5.2 -females) and lowest in group 0 (22.0 +- 4.7 - males, 15.6 +- 4.5 - females). Groups B and AB had values of 23.0 +- 5.2 (males) 16.3 +- 3.2 (females) and 23.3 +- 3.8 (males), 16.5 +- 6.8 (females) respectively. The TIBC value (micromol/L) was highest in group A (60.2 +- 9.0 - males, 42.7 +- 6.0 - females) and lowest in group 0 (51.8 0 +- 14.2 - males, 36.8 +- 12.2 - females), while the values for groups B and AB were 54.7 +- 7.5 (males), 38.8 +- 2.5 (females) and 54.4 +- 4.8 (males), 38.6 +- 3.8 (females) respectively. The percent TS was highest in the group A (43.7 +- 2.0 - males, 31.0 +- 1.0 - females) and lowest in those of B (42.0 +- 1.4 - males, 29 +- 0.4 - females) while groups AB and 0 had values of 42.8 +- 1.0 (males), 30.4 +- 3.0 (females) and 42.5 +- 1.9 (males), 30.2 +- 4.8 (females) respectively. There were significant differences between the intra group comparisons of the results of groups A and O only in the serum iron and TIBC parameters. No significant differences were observed in the percentage TS among the different blood groups. The values obtained for the percentage distribution of the different blood groups agrees with already established values for the population. Since the values obtained for the parameters studied all fall within the normal range, this work provides useful data on the environment of South Eastern Nigeria.Key Words: Serum Iron. Total Iron Binding Capacity. ABO Blood Groups. Transferrin Saturatio

Monkeypox during Covid-19 era in Africa: Current challenges and recommendations

In May 2022, monkeypox virus (MPXV) outbreak was confirmed amid the coronavirus disease 2019 (COVID-19) pandemic in many parts of the world including Africa. This is the largest outbreak since monkeypox (MPX) was first detected in humans in 1970. The MPX outbreak in Africa is an added burden to the fragile healthcare systems that are already overburdened with several reoccurring epidemics. Although several efforts are in place to effectively contained the outbreak. Several measures such as improved surveillance and diagnostic are necessary to contain the spread of the disease in Africa. This commentary highlights the challenges with the MPX outbreak in Africa and discusses the measures that can be taken to limit the spread of the disease, particularly in high-risk countries

Factors affecting rehabilitation seeking behaviour of individuals with legal blindness in Lagos, Nigeria

Blindness and low vision have profound negative impact on the quality of life of persons affected and it reduces ability to live independently. There are apparent inadequacies in vision rehabilitation services (VRS) in terms of access to and uptake of  VRS. This study investigated factors affecting VRS seeking behaviour of 120 legally blind participants in Lagos, Nigeria. Participants had Visual Acuity (VA) worse than 6/60 (+1.0LogMAR) and were aged between 20 and 80 years. Eighteen (18, 15%) of the participants reported having undertaken VRS while 102 participants (85%) reported that they never had any form of VRS. Data concerning reasons for non-uptake of VRS were obtained from the 102 participants (85%) who reported that they had never taken any VRS after diagnosis of visual impairment. Findings show that a majority of the participants who had never had VRS had no knowledge of VRS (86, 84.31%) and many of them reported that they were never referred for VRS (82, 80.39%). Logistic regression analysis of reasons for non-uptake of VRS showed that males were significantly less likely to report that they had no knowledge of VRS (OR:0.53; 95% Confidence Interval [CI], 0.31-0.91; p<0.05). Participants aged 61 years and over (OR: 1.48; 95% CI, 0.72-3.09; p<0.05) as well as those blind for more than eleven years (OR: 1.16; 95% CI, 0.56-2.34; p<0.05) were more likely to report that VRS was not needed. Participants aged 61 and over were also more likely to state that they were never referred for VRS (OR: 2.88; 95% CI, 1.62-5.20; p<0.05). The study concludes that there is a need to increase awareness and knowledge of VRS among low vision patients as well as provide accessible infrastructure and manpower for VRS. A case is also made for prompt referral of legally blind patients for VRS

Effect of Neem, Siam Weed and Vetiver Oils on Physiological Reactions and Fitness of House Fly, Musca domestica L

Insecticidal activities of hexane extracts of leaves and roots of siam weed and vetiver, and roots of neem were assessed against house fly, Musca domestica L. Mortality test was conducted using serial concentrations 20%, 10%, 5% and 2.5% of extracted oils while behavioural orientation of house fly to oil odour, antioviposition effect of oil toward the insects, biochemical reactions in treated flies and fitness of offspring were determined using 20% oil concentration. House fly mortality varied significantly with plant species and part of plant extracted (P < 0.001), concentration applied (P < 0.001) and time post-exposure (P < 0.001). All tested plant extracts showed potential as good control agents with average mortality ranging from 59-74%. However, significantly lower median lethal values (LC50 and LT50) separated vetiver as the most toxic plant against the insect pest. The plant oils repelled house flies (93-100%), reduced the number of larvae that hatched from laid eggs, lowered adult emergence and caused a significant reduction in size and weight of offspring. On the contrary, exposure to plant oils did not alter offspring sex ratio. In comparison to untreated house flies, plant oils induced biochemical stress in poisoned cohorts as evidenced in significant deviation of digestive enzyme (α- and β- amylases, lipase) activity and concentrations of detoxifying enzyme (glutathione-Stransferase), neurochemical enzyme (acetylcholinesterase) and energy metabolism biomolecules (total protein). Implications of obtained results for non-chemical control strategies are discussed

Building a Sustainable Innovation Ecosystem in Universities for Ideation and Entrepreneurial Competence: The University of Lagos Experience

What is new? Universities in the global south particularly in sub-Saharan African countries have not impacted greatly on their host communities as research efforts in these universities are not linked to innovation addressing societal challenges. What was the approach? The University of Lagos (UNILAG), recognizing that a robust innovation ecosystem is central to building capacity in the innovation space for unleashing the creative potentials of both faculty and students beyond traditional teaching and research, activated three units to drive innovation-related activities in the university. This article presents critical discussions on the University of Lagos’s experience in driving innovation through novel institutional frameworks facilitated by the Research Management Office, the Innovation & Technology Management Office, and the Entrepreneurship & Skills Development Centre. The article also presents challenges encountered in the process and strategies employed to successfully navigate through the challenges, lessons learned, successes recorded in patents and intellectual property management, as well as future directions for greater impact. What is the academic impact? The paper makes recommendations for sustainability and for the implementation of efficient strategies in newly established units seeking to strategically drive innovation-related activities. What is the wider impact? Practical implications of the UNILAG’s experience for Research and management practitioners in developing countries are articulated