Rainfall intensity-duration-frequency analysis for Southeastern Nigeria

Inadequate hydrologic data and the need for proper planning of water resources development have forced engineers to analyze available data more critically.  This is particularly so in developing countries.  The Intensity-Duration-Frequency (IDF) relationship is one of the most commonly used basis for water resources planning and development.  This study analyzed rainfall data and characteristics for locations in seven states of Southeastern Nigeria.  IDF curves were developed for these locations using two methods (Graphical and Statistical) and the results were compared.  The locations are Onitsha in Anambra State, Enugu in Enugu State, Abakiliki in Ebonyi State, Umuahia in Abia State, Owerri in Imo State, Port Harcourt in Rivers State and Uyo in Akwa Ibom State.  Break-point, short duration, rainfall data are not generally available in the historical records at the locations.  Generalized accumulated rainfall patterns developed by USDA Soil Conservation Service were matched with rainfall data for the locations of study, and the advanced pattern had the best fit with the observed characteristics and was used to break down recorded daily totals into shorter duration rainfall data.  The method of annual maxima series was used to select data sets for the rainfall analysis.  In the statistical method, the Type I extreme-value distribution (Gumbel) was applied to the annual maximum series for each of the seven stations to estimate the relevant parameters of the IDF model.  The non-parametric Kolmogorov-Smirnov test and the χ2 test were used to confirm the appropriateness of the fitted distributions for the locations.  IDF data developed from the graphical and statistical methods applied were very close for the lower return periods of two to ten years, but differed for higher return periods of 50 to 100 years.  However, the difference is not significant at 5% level.  The data developed by either of the methods will facilitate planning and design for water resources development in Southeastern Nigeria.Keywords: rainfall, intensity, water resources, hydrologic data Citation: Okonkwo G. I., and C. C. Mbajiorgu.  Rainfall intensity-duration-frequency analysis for Southeastern Nigeria.  Agric Eng Int: CIGR Journal, 2010, 12(1): 22-30

Performance evaluation of sprinkler irrigation system at Mambilla beverage limited, Kakara-Gembu, Taraba state-Nigeria

Irrigation systems are designed to achieve a desired efficiency which in turns improve food productivity. This paper evaluated the Kakara Tea Irrigation System (KTIS) based on its coefficient of uniformity CU, delivery performance ratio (DPR), irrigation p roductivity (IP), labour requirements and water quality. Standard procedure was used for the evaluation. Christiansen’s equation was used to compute CU. EDTA and flame photometer methods were used to analyse water quality. The result indicated that KTIS h as a CU of 90.9%, DPR of 0.79 which indicated an efficiency of 79%. Sprinkler discharge rate was 1.2l/s and application rate was 7.5mm/hr. It is capable of irrigating 41.1ha/day with an average irrigation cycle of 9days and irrigation productivity of 2613. 7kg/ha. Total irrigation production contributes 68.6% to the annual production; case study of 2016 production record. The exchangeable cations analysis of Kakara irrigation System water indicates thus; Na (0.75mgL-1), Ca (1.01mgL-1) and Mg (0.20mgL-1) and Sodium adsorption ratio (SAR) value of (9.64mmoleL1 ), while the pH was 5.6. The result also indicated variation in discharge. Comparing the irrigation productivity (IP) with previous production records from 2011 - 2016 showed good irrigation performance tre nd of Mambilla Beverage Company irrigation scheme. However, the system is labour intensive since the laterals have to be moved after some period of time. The implementation or adoption of permanent laterals and risers will reduce manual labour demand. Variation in discharge can also be adjusted via use of uniform laterals, risers, and nozzles. This study further recommends an incorporation of a soil and water laboratory for the company to aid in monitoring the soil and water quality of the irrigation area. Keywords: Tea, irrigation System, Performance Evaluatio

Development of a single stage roselle calyx extractor

An 8-litre capacity roselle calyx extractor was developed with Arduino based temperature controls ranging from 30 to 100⁰C. Performance evaluation conducted on the extractor showed that efficiency of the extractor increased as the weight of the calyces decreased at constant mass of water which ranged from 55% to 89%. The effect of extraction time (5, 10 and 15 minutes), process temperature (30, 50, 75 and 100⁰C) and calyx-water mass ratio (1:50, 1:20 and 1:10) on the pH, density and colour of the extract was determined. The pH ranged from 2.4 to 2.9 and density was from 1.02 to 1.05gcm-3. Statistical analysis conducted showed that temperature and calyx-water mass ratio has a linear significant effect (p<0.001) on all the responses while time had a linear significant effect (p<0.001) on all responses except density. Time and temperature had interaction significant effect (p<0.01) on pH, while temperature and calyx-water ratio had interaction significant effect (p<0.01) on the density of the extract. Calyx-water ratio had a quadratic significant effect (p<0.001) on the pH and colour of the extract. The contour plots presented the interactions between the factors and their responses. This study demonstrated that roselle calyces extract can be produced more efficiently than practices currently available and also that processing conditions are very important in the quality of extracts produced

Strength Variation of OPC-Saw Dust Ash Composites with Percentage Saw Dust Ash

This work investigated the variation of OPC-Saw Dust Ash (SDA) composites strength with percentage SDA. 231 concrete cubes, 231 sandcrete cubes, and 231 soilcrete cubes of 150mm x 150mm x 150mm were produced at percentage OPC replacement with SDA of 0% (control), 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50% and crushed to obtain their compressive strengths at 3, 7, 14, 21, 28, 50, and 90 days of curing. For concrete, the 90-day strength values decreased from 28.00N/mm2 at 5% SDA to 25.60N/mm2 at 15% SDA to 20.50N/mm2 at 35% SDA to 15.80N/mm2 at 50% SDA, while the control value was 27.00N/mm2. The 90-day strength values also decreased from 11.50N/mm2 at 5% SDA to 5.40N/mm2 at 50% SDA for sandcrete while the control value was 11.10N/mm2. Soilcrete strength values decreased from 9.70N/mm2 at 5% SDA to 4.50N/mm2 at 50% SDA while the control value was 9.50N/mm2. The results suggest that, with good quality control of the concreting process, 5% to 25% OPC replacement with SDA could be suitable for general reinforced concrete works, 25% to 40% for minor works in concrete, and 45% to 50% for plain concrete works. Also, 5% to 20% OPC replacement with SDA could be used for light load-bearing sandcrete and soilcrete works, while 25% to 50% could still be suitable for non-load-bearing works. Keywords: Blended cement, Composites, Compressive strength, Concrete, Sandcrete, Saw dust ash, Soilcrete

ANALYSIS AND COMPUTER SIMULATION OF A NATURAL CONVECTIVE SOLAR- HEATED ANIMAL BUILDING

A model has been developed to predict the outlet air temperature and air flow rate from a solar collector based on the theory of thermal buoyancy. A high capacitance solar collector directly coupled to an animal building absorbs solar radiation, which heats up air and forces entry into the building by convection. In order to test the validity of predictions of the model measured outlet air temperatures of the solar collector are compared to the predicted values and the results are presented. The predictions of outlet temperature and air flow rate agree reasonably well with experimental data, differences being of less than 1.5% significance. [Global Jnl Engineering Res. Vol.1(2) 2002: 127-136

AUDIENCE PERCEPTIONS AND ATTITUDES ON MEDIA COVERAGE OF HIV AND AIDS PANDEMIC IN LIMPOPO PROVINCE, SOUTH AFRICA

South Africa has the highest HIV and AIDS prevalence in the world despite theefforts by all stakeholders to mitigate its spread and start reversing the rate of newinfections. It is also evident that the general public depend on the media for theirinformation and educational needs concerning the disease. However, HIV andAIDS prevalence rate is still very high in Limpopo province. The HIV and AIDSincidence rate is equally high in South Africa, as well as in the Limpopo province.This study investigates audience perceptions and attitudes towards mediacoverage of the HIV and AIDS and factors fuelling the pandemic in the province.A detailed questionnaire was used to collect data from residents of Bochum inCapricorn District, Thohoyandou in Vhembe district, Phalaborwa in Mopanidistrict, and Jane-Furse in Sekhukhune district of the Limpopo province. Thestudy indicated that most residents in the province have positive perceptions aboutmedia coverage of the pandemic. In spite of the extensive media coverage, theirattitudinal responses were not quite encouraging. The study highlighted that themajor factors influencing audience attitudinal response to media coverage of thepandemic include: poverty, rape, Sexually Transmitted Diseases (STDs), alcoholand drugs, and unplanned teenage pregnancy. This study recommends that anyHIV and AIDS mitigation strategy in the province should take into consideration the aforementionedfactors and that the media should consistently and adequatelyreport on the pandemic as one of the development challenges of the province

Evaluating Nigeria’s position on intended nationally determined contributions under the 2015 Paris agreement and the sustainable development goals

This article examines Nigeria’s commitment to combating the global scourge of climate change using the sustainable development goals and the Paris Agreement of 2015. Nigeria having signed various global Multilateral Environmental Agreements (MEAs) such as the celebrated Paris Climate Change Agreement signed in 2015 on addressing the challenge of climate change such as United Nations Framework Convention on Climate Change (UNFCCC) and others, need to be scored on how well it has keyed into the global environmental reality of addressing climate change through its Intended Nationally Determined Contributions (INDCs). This article concludes with recommendations on ways the Nigeria can implement its further obligations under the Paris Agreement

Genetic diversity and distribution of Mycobacterium tuberculosis genotypes in Limpopo, South Africa

Abstract Background Tuberculosis remains a major health problem and knowledge of the diversity of Mycobacterium tuberculosis strains in specific geographical regions can contribute to the control of the disease. This study describes the genetic profile of M. tuberculosis in five districts of Limpopo Province. Methods A total 487 isolates were collected from the National Health Laboratory Services from all regions/districts of Limpopo Province. Only 215 isolates were confirmed to be M. tuberculosis by Bactec Mycobacterium Growth Indicator Tube 960® and Rhodamine-Auramine staining. Isolates were subcultured on Löwenstein-Jensen medium agar slants to validate purity. They were spoligotyped and data analysed using the international spoligotyping database 4 (SpolDB4). Results Of the 215 isolates, 134 (62.3%) were genotyped into 21 genotype families while 81 (37.7%) were orphans. The 81 orphans were further subjected to resolution employing SpolDB3/RIM. Overall, the study revealed a high diversity of strains of 32 predominantly the non-Beijing lineages: the LAM- LAM3 (9.8%), LAM9 (4.7%) and LAM11- ZWE (3.3%), the T-T1(15.0%), T2 (0.9%), T2-T3 (1.4%), the CAS-CAS1-Delhi 5 (1.9%) and CAS1-KILI (1.4%) the MANU2 (1.4%), U (0.5%), X-X1(1.4%), X3 (1.9%), S (9.8%), CAS (1.4%), LAM7(0.9%), T3(0.5%), LAM8(4.7%), T4(1.4%), X2(0.4%), AI5(1.9%), LAM1(0.5%), FAMILY33 (1.9%), EAI4(1.4%), M. microti (1.9%). The Beijing and Beijing-like families were (14.9%) and (0.9%), respectively. A total of 28(13%) clusters and 77(36%) unique cases were identified. Beijing strain (SIT 1) formed the biggest cluster constituting 14%, followed by LAM3 (SIT 33), T1 (SIT 53) and LAM4 (SIT 811) with 7%, 5.1% and 2.8%, respectively. The Beijing family was the only genotype found in all the five districts and was predominant in Mopani (18.8%), Sekhukhune (23.7%) and Vhembe (23.3%). Dominant genotypes in Capricorn and Waterberg were LAM3 (11.9%) and T1 (13.3%), respectively. Conclusion A wide diversity of lineages was demonstrated at district level. A high number of clusters per district provided evidence of on-going transmission in this Province