Aspects of the Growth and Reproductive Biology of the Guinean Tilapia, Tilapia guineensis (Bleeker, 1862) in a Tropical Freshwater Lake, Nigeria

Aspects of the growth and reproductive biology of the Guinean Tilapia, Tilapia guineensis from Asejire Lake was investigated from January, 2013 to December, 2013. Significant relationships(r> 0.89) occurred between the length and weight of T.guineensis for the combined, male, female and every month.  The values of the parameter slope (b) in the length-weight relationship being less than 3 indicated negative allometric growth. The mean condition factor (2.023 ± 0.01) being greater than one showed the fish is in good condition in the freshwater environment.  The multiple peaks observed in the gonadosomatic index signify the species is a multiple spawner. Fecundity of Tilapia guineensis ranged from 3418 – 9852 eggs for a fish with total length 18.9 cm to 29.7 cm respectively Keywords: Tilapia guineensis, length weight relationship, gonad maturity stages, fecundity, freshwater environmen

Synchronous Generator Excitation Chatter-Free Sliding Mode Controller

A chatter-free sliding mode controller (SMC) for synchronous generator excitation is presented in this paper. A linearized model of a single machine connected to an infinite bus is employed to design a variable-structure controller which not only stabilizes the system, but also ensures that this is maintained in the face of system parameter variations. Validating the robustness feature of an SMC, simulation results that show the dynamic performance of the system under both constant excitation and SMC-controlled excitation are presented

Second kind Chebyshev collocation technique for Volterra-Fredholm fractional order integro-differential equations

In this work, we present the numerical solution of fractional order Volterra–Fredholm integro-differential equations using the second kind of Chebyshev collocation technique. First, we transformed the problem into a system of linear algebraic equations, which are then solved using matrix inversion to obtain the unknown constants. Furthermore, numerical examples are used to outline the method’s accuracy and efficiency using tables and figures. The results show that the method performed better in terms of improving accuracy and requiring less rigorous work.©2022 JNSMR UIN Walisongo. All rights reserved

Second kind Chebyshev collocation technique for Volterra-Fredholm fractional order integro-differential equations

In this work, we present the numerical solution of fractional order Volterra–Fredholm integro-differential equations using the second kind of Chebyshev collocation technique. First, we transformed the problem into a system of linear algebraic equations, which are then solved using matrix inversion to obtain the unknown constants. Furthermore, numerical examples are used to outline the method’s accuracy and efficiency using tables and figures. The results show that the method performed better in terms of improving accuracy and requiring less rigorous work.©2022 JNSMR UIN Walisongo. All rights reserved

Second kind Chebyshev collocation technique for Volterra-Fredholm fractional order integro-differential equations

In this work, we present the numerical solution of fractional order Volterra–Fredholm integro-differential equations using the second kind of Chebyshev collocation technique. First, we transformed the problem into a system of linear algebraic equations, which are then solved using matrix inversion to obtain the unknown constants. Furthermore, numerical examples are used to outline the method’s accuracy and efficiency using tables and figures. The results show that the method performed better in terms of improving accuracy and requiring less rigorous work.©2022 JNSMR UIN Walisongo. All rights reserved

Clinical Features and Pattern of Presentation of Breast Diseases in Surgical Outpatient Clinic of a Suburban Tertiary Hospital in South-West Nigeria

Objective: To characterize the clinical features and pattern of presentation of breast diseases as observed in our practice. Materials and Methods: A prospective study of 121 consecutive patients with breast complaints presenting in our Surgical Outpatient Clinics. The relevant data were collected by two surgeons using the prescribed forms and was analyzed using Epi Info 2003, Mann–Whitney (test of two groups) Chi-squared and Fishers exact test was used to compare parameters of benign and malignant groups. P value <0.05 was considered as significant. Results: One hundred and nineteen patients were females, two were males. The age range was 14–70 years. Forty two (34.7%) patients were in the 21–30 year age group. The commonest symptoms were breast lump in 111 (91.7%) patients, and breast pain in 28 (23.1%) patients. Breast pain was a significant presenting complaint in patients with breast malignancy (P=.026). On clinical examination 103 (85.1%) patients had palpable lumps, and seven patients were normal. Forty four patients (36.3%) had malignant disease, seventy patients (57.8%) had benign breast diseases and seven were normal. Fifty nine of the 70 benign diseases were fibroadenoma. One hundred and three patients (85%) had appropriate therapy, while 18 patients (14.8%), including eight with malignant disease absconded. Conclusion: In the study, a breast lump was the commonest clinical feature of breast disease. Over 60% of these were benign. Breast pain was a statistically significant presentation in patients with malignant breast disease. One in seven of the patients absconded.Keywords: Breast lumps, breast malignancy, breast pain, fibroadenomaNigerian Journal of Surgery, Jan-Jun 2012 | Volume 18 | Issue

Investigation of the Performance of of Synchronous Generators Equipped with Nonlinear Excitation Controller

Investigation of the dynamic performance of a synchronous generator connected to an infinite bus (SMIB) system is carried out in this paper. The generator is equipped with a nonlinear excitation control law based on the concepts of geometric homogeneity and feedback linearization. A new positive parameter, called the dilation gain, is introduced in the control law for improved damping of oscillations and better dynamic performance. Two models of the system are employed for the study, and a disturbance in form of a network fault with varied durations is applied to test the performance of the system. Simulation results as well as MATLAB® code for testing for exact linearization of an affine nonlinear system are provided

Prediction of Pressure Drop in Subsea Pipeline Using Pipesim Software

The number of offshore developments for which long-distance tie-back is usually implemented has increased recently, leading to increasing pressure loss concerns from such systems. In the literature, it revealed that pressure drop in multi-phase transport is quite complex to compute manually. Hence the need for multi-phase flow simulation software. PIPESIM is a leading industry software currently used in the oil and gas industry for multiphase flow simulation. In this study, a 64km subsea pipeline system comprising two sections; 23km, 22.064in ID and 41km, 24inch ID, coated with 3mm (0.003m) polyethene insulation and transporting multiphase hydrocarbon fluid in an ultra-deep-water field was modelled in PIPESIM. Network simulation for the base case was carried out at 114barg (114MPa) inlet pressure and 18.7MMSCfd gas flowrate. The observed system pressure drop was dependent on pipeline inlet pressure, flowrates, and internal pipe diameter. 13.8barg (13.8MPa) was lost from the system for the base case simulation. Sensitivity analysis carried out using Gas volumetric flowrates of 3, 12 and 18.7 MMSCFd. The inlet pressures of 57, 114 and 171barg combined with six different pipe diameters generated a unique combination of 81 data points that were used in the development of a pressure drop correlation using the LINEST regression analysis tool in Microsoft Excel. At high flowrate and high inlet pressure, the pressure-drop observed was minimal and vice versa. Also, at constant flowrates and inlet pressures, the pressure drop was observed to increase with increasing pipe sizes. An R2 value of 0.9226 was obtained from the analysis. The plot of Predicted Pressure-drop against Calculated pressure-drop similarly gave an R2 value of 0.8025. Both results showed usefully, and hence the developed correlation can be used as an estimate in the absence of PIPESIM software for pressure drop prediction purposes. Keywords: Pressure drop prediction, Multi-flow Simulation, PIPESIM, Pipe sizing, Regression Analysis DOI: 10.7176/IEL/10-2-06 Publication date:March 31st 202

Assessment of Water Provision and Associated Risks Among Children in Abeokuta Peri-Urban, Ogun State, Southwestern Nigeria: The Gender Implications

An assessment of water supply challenges and risks facing children in selected peri-urban areas of Abeokuta (Akole-Oke Ata, Obatonko, Adigbe) in Ogun, southwestern Nigeria, was carried out during the dry season, in the months of November 2013 to February 2014. Recognizing that the yield of drinking water sources and water supply from the government were drastically reduced during the dry season, in this study, project leaders aimed to determine children’s involvement in household water provision during the dry season in the peri-urban of Abeokuta Ogun State Southwestern Nigeria, and to further determine the gender distribution, risks and risk indicators, and occurrence of problems among the children during water provision. In the course of the study, a total of 100 water sources (piped water taps, boreholes, dug wells, burst pipes, streams) were visited, and focus group discussion/informal interview methodologies were adopted to gather data from the people at water points. Approximately 827 of the people met at the water points were children, with 800 of those children being girls between the ages of 5-15. The results from these interactions indicated that the girls from each household were responsible for scouting water sources, as well as transportation and storage of the water for household consumption. Out of 800 girls interviewed, 722 reported being late to school, 712 recorded poor school attendance, 456 reported being sexually harassed and/or assaulted, 166 had experienced injury experienced neck and back pain from carrying an excessive load of water, 99 were physically punished by parents or guardians at home when containers got lost, misplaced, or exchanged at the water points, and 184 were punished by the parents or guardians who believed that the girls wasted the water. Some of the respondents (12) preferred going out to provide the water for the family to avoid other domestic work. The majority said they wanted the government and/or parents/guardians to be responsible for adequate water provision for household consumption