Volume 6, Issue 5
EVALUATING THE SUITABILITY OF AUTOMOTIVE GAS OIL (DIESEL) FUEL FOR GAS TURBINE LP COMBUSTOR OPTIMUM PERFORMANCE ACROSS LEAN EQUIVALENCE RATIOS [PDF]
Wilson Alli, Osagie Ighodalo and Christopher AjuwaThis work investigated the suitability of Automotive Gas Oil (AGO) fuel for optimum performance in the gas turbine engine lean premixed combustor at varying equivalence ratios. The process entails the numerical simulation of Automotive Gas Oil in a lean premixed combustor at different varying lean equivalence ratios. The computational fluid dynamics (CFD) technology using the ANSYS Fluent code (Academic Research CFD) version 16.2 was adopted to investigate the characteristic of the AGO during intense combustion activities at lean equivalence ratios (0.3,0.5,0.7 and 0.9)ϕ through the direct numerical simulation (DNS) processes. An AutoCAD pre-designed combustor was exported to the ANSYS Fluent GUI for fine tuning, gridding/mesh generation and discretisation process with the ANSYS Fluent solver while leveraging the finite difference method (FDM) to solve emerging complex equations. With the established combustor boundary conditions similar to an operational industrial gas turbine engine generating at 20MW. Simulations were conducted in both the steady-state and transient combustions regimes to evolve details of respective fuel combustion mannerism profiles on simulation convergence attainment. The obtained result detail of the dynamic, total pressures, acoustic amplitudes contours with CH* and OH* mass fractions for each fuel simulated under four equivalence ratios were analysed and tabulated. The outcome-based on parameters per equivalence ratio were analysed and compared to establish differences to proffer responses to the primary objectives of the research theme. The outcome revealed steady temperature range occurring between the equivalence ratio rate with the maximum temperature reading of 1044.38k at 252kPa at 0.5ϕ
SECURITY ENHANCEMENT & SOLUTION FOR AUTHENTICATION IN CORPORATE NETWORK WITH FIREWALL CONFIGURATION AND AUTHENTICATION FOR SERVER PROTOCOL [PDF]
Syed Jamaluddin Ahmad, Roksana Khandoker, Farzana Nawrin Firewalls are used to protect networks from malicious traffic from the outside and Limit the flow of information from inside protected networks to the outside world. Most firewalls filter traffic based on network addresses and packet contents. Unfortunately, one major goal of firewalling that of limiting the users and programs that can communicate, is not well served by such designs: it is difficult to accurately map network addresses and packet contents to user and program names. Firewalls can solve the problem of securely mapping user names to addresses when filtering inbound traffic from un trusted networks through the use of covert authentication systems such as port knocking and single packet authorization. Egress firewalls can identify users and programs on trusted networks through the use of application filters. In this thesis, I survey the current state of both types of systems, describe their weaknesses, and introduce techniques to alleviate some of these weaknesses.
EFFECT OF TRAMADOL ON BIOCHEMICAL PARAMETER USING MALE ALBINO RATS [PDF]
Nwaogwugwu, C.J ., Egege A.N.,Okereke S.C., Ezekwe A.S., Akara E.U Analgesics are the traditional pain killer medications that are easily and commonly consume for different types of aches and pains. But the way young people abuse it is in increase in the society.The present study investigated the effect of Tramadol administration on renal, liver and body weight on albino rats. The present study was conducted to assess the effects of Tramadol on both liver and kidney functions biomarkers using albino rat. Antioxidant levels, hematological parameter, liver, kidney histopathology were also evaluated.
THE UNITED NATIONS SECURITY COUNCIL REFORMS [PDF]
Sandesha Perera The need to reform the United Nations has been a widely discussed topic. Yet these reforms have been always obstructed due to the lack of consensus of the states. This paper pays attention mainly to the United Nations Security Council (UNSC) reforms and Veto power reforms while there are many more areas where reforms are needed. Security Council reforms are always a debatable topic in the UN agenda and considered as difficult to be reformed. This research is mainly based on qualitative data which provide in depth analysis into the discussed phenomenon. For the study it has utilized mainly the secondary data obtained from UN documents, journal articles and books. It is discussed that the Security Council needs to be broadened giving way to member states to represent them in the UNSC without confining it to the 5 powerful members who have been using the power for more than 7 decades so far. Also there have been debates that veto power should be abolished, which is again doubtful as the veto power holding members have to give their consent for that. Therefore all these reforms are merely for the time being word sake reforms which cannot be put in to practice in reality.
THE EFFECT OF ADDITIONAL PAPAIN CRUDE ENZYME IN FED ON THE GROWTH RATE OF BARB JUVENILE (OSTEOCHILUS HASSELTI) IN FLOATING NET CAGE AQUACULTURE CIRATA RESERVOIR [PDF]
Rita Rostika,Titin Herawati,Akhmad H.K. Suhendar, Lantun P. Dewanti The aim of this research was to determine the effect of addition of papain crude enzyme with different doses in feed and optimal doses that can produce the highest barb juvenile growth rate in floating fish cage aquaculture Cirata Reservoir. The research was conducted from March until May 2016 in laboratory of research and service of chemical at FMIPA UNPAD and floating net cage aquaculture of BPPPUIH Cirata Reservoir. The method implemented was experimental method using Group Randomized Design (GRD) with five treatments and three replications. The treatments were five level of the amount of papain crude enzyme on feed (0%, 2.25%, 3.00%, 3.75%, and 4.50%). The results showed that the papain crude enzyme with protease activity 12.63 Unit/mg protein was able to increase the value of daily growth rate and feed efficiency of barb juvenile. The amount of 3.00% papain crude enzyme on feed gave the highest results upon daily growth rate (1.76%/ day) and, feed efficiency (37.70%) with survival rate (98.00%).
IMPROVEMENT OF NIGER DELTAIC PROBLEMATIC SOILS WITH COSTUS AFER BAGASSE FIBRE ASH AND CEMENT AS STABILIZERS [PDF]
Charles Kennedy, , Gbinu Samuel Kabari, Terence Temilade Tam Wokoma This research work evaluated the engineering properties of Niger deltaic problematic clay and lateritic soils from Odioku Community road in Ahoada West Local Government, in Rivers State, stabilized with cement and costus afer bagasse ash (Bush Sugarcane fibre ash (BSBFA) to improve the CBR value of the subgrade and strength. The results of compaction test of soils obtained of maximum dry density (MDD) and Optimum moisture content (OMC) relationship of soil + cement + BSBFA treated soil of combined actions of percentage ratios, 2.5% +2.5%, 5.0% + 5.0%, 7.5% + 7.5% and 10% + 10% of cement and bagasse fibre ash (BSBFA) at corresponding ratios to clay and lateritic soils. OMC values of clay / laterite + cement + BSBFA increased from 12.39% to 12.79% (clay) and 11.79% to 14.02% (laterite). MDD increased from 1.640KN/m3 and 1.78 KN/m3 (clay) and 1.803KN/m3 and 1.860KN/m3 (laterite). Results of CBR test showed an increased to corresponding increased in additives, for clay soil, an increased from 7.6% to 13.9% (clay) and 9.8% to 35.3% (laterite). At optimum ratio of 85% + 7.5% + 7.5% of soils + cement + BSBFA. UCS of soils + cement + BSBFA with ratios ad above showed an increased values of 78.6kPa to 623kPa (clay) and 155kPa to 874kPa. Consistency limits results of index properties of soil + cement + BSBFA showed decreased values from 36.8% to 31.2 (clay) and 22.8% to 19.5%. The entire results showed the potential of using bagasse BSBFA as admixtures in cement treated soils of clay and laterite.
RESIDUAL FLEXURAL STRENGTH OF CORROSION INHIBITED RESIN COATED BEAM IN CORROSION ACCELERATED MEDIA [PDF]
Charles Kennedy, Ogunjiofor Emmanuel Ifeanyi, Letam Leelee Prince This work experimented on the effects of corrosion and inhibitors (Inorganic origin) extracts known as resins/exudates from trees barks on the residual flexural strength of concrete beam members immersed in corrosion accelerated medium for 90 days to ascertain possible changes on surface conditions of investigated samples. Steel reinforcement of umcoated and coated one of various thicknesses of 150µm,(ABC), 250µm (DEF) and 350µm (GHI) steel bars were embedded into concrete and tested for corrosion potential possibility. Results from this experimental test recorded corrosion potential with visible signs of cracks, color change and spalling. Further results obtained of corroded concrete beam members were 22,50%, 39.30%, 10.19% and 46.30 of failure load, midspan deflection, ultimate tensile strength and elongation, for non- 29.09%, 28.30%, 12.03% and 31.50%, for coated beam members , 28.5%, 25.30%, 12.13% and 32.12% respectively. These results indicated increased in flexural failure load and ultimate tensile strength and decreased in midspan deflection and elongation respectively in corroded concrete beam members. This showed lower load and higher deflection in corroded members and higher in non-corroded and coated, higher elongation in corroded and lower in non-corroded and coated.
COMPARATIVE EVALUATION OF EFFECTIVENESS OF CEMENT / LIME AND COSTUS AFER BAGASSE FIBER STABILIZATION OF EXPANSIVE SOIL [PDF]
Charles Kennedy,Tamunokuro Oswald Amgbara, Terence Temilade Tam Wokoma The study evaluated the geotechnical properties of an expansive clay soil found along Odioku – Odiereke road in Ahoada-West, Rivers State, in the Niger Deltaic region. The application of two cementitious agents of cement and lime, hybridized with costus afer bagasse fiber to strength the failed section of the road. The preliminary results obtained classified the soil as A-2 -7 on the AASHTO classification scheme and soils at natural state are percentage (%) passing BS sieves #200 are 80.5%. The soils from wet to dry states are dark grey in color with consistency limit properties of liquid limit of 56.1 %, plastic limit of 22.4 %, plasticity index of 33.7%. The specific gravity properties are 2.65 % and natural moisture content 45.5 %. The compaction characteristic properties were optimum moisture content 12.39 %, Maximum dry density 1.64kN/m3. The preliminary investigation values indicated that the soils are highly plastic. Results obtained of compaction test of Optimum moisture content (OMC) and maximum dry density (MDD) of clay soils + cement + bush sugarcane bagasse fibre (BSBF) reinforced soils at combined actions to soil ratios of 3.75% + 0.25%, 5.5% + 0.5%, 7.25% + 0.75% and 9% + 1.0% of cement and BSBF combined percentages. OMC of soil + cement + BSBF treated soils increased from 12.93% to 13.10% (clay) and soil + lime + bagasse fibre treated soils, OMC increased from 12.93% to 24.61% (clay) with 90.332% higher of lime compared to that of cement. MDD of (clay), soil + cement + BSBF of ratio above increased from 1.640kN/m3 and 1.79kN/m3 and soil + lime + bagasse fibre treated soils increased from 1.640KN/m3 to 1.864KN/m3 (clay), with 3.91% higher in cement treated. CBR test results of (clay) soil + cement + bagasse fibre (BSBF) increased from 7.6% to 24.7% and lime + soil treated, increased from 7.6% to 16.4% with 50.6% higher in cement treated soil, both cement / lime + BSBF having an optimum inclusion percentage ratio of soils 92% + cement 7.25 + BSBF 0.75%. UCS test results of soil + cement + BSBF increased from 78.6kPa to 678kPa while soil + lime + BSBF increased from 78.6kPa to 308kPa, with 120.1% higher in cemented to lime treated. Consistency limits test results showed decreased values from 56.1% to 47.9% (clay) soil + cement + BSBF treated soils and soil + lime + BSBF treated soil, LL decreased from 56.1% to 47.7%. Entire results showed strength increased in clay soil with the composite materials, with higher values in cement to lime treated soil.
ROAD TRAFFIC ACCIDENT CHARACTERISTICS IN NIGERIA:A SIX YEARS REVIEW [PDF]
Oluwasegun O. Aluko This paper presents road traffic accident (RTA) as a violence the public should worry about due to its economic and social cost. It goes further to analyse crash data to show the trend in RTA in Nigeria over a period between 2011 and 2016. From the analysis, it was also found that male and adult were over represented amidst crash victims. A review of the causes of accident showed that human error contributes over 82% to RTA while road and environmental condition contributed less than 3%. The paper concludes by admitting that while available data might still be inadequate in providing extensive information about road safety for appropriate modelling and predictions, it still offers sufficient information for policy makers to be guided on where to pay attention to.
THE EFFECT OF BOARD CHARACTERISTIC ON FIRM FINANCIAL PERFORMANCE [PDF]
HMDN Somathilake The currently business environment is characterized by uncertainty and risk, making it in-creasing difficult to forecast and control the tangible and intangible factors which influence firm performance. The performance of an organization depends on its governance, directors and their attitudes. Therefore should be more attention corporate governance. Among corporate governance characteristics board characteristics take major place. The study explores the effect of board characteristics on firm financial performance of listed companies in Colombo Stock Exchange (CSE) during the period of 2015/2016-2016/2017. The research employs 100 listed high turnover companies for the study. Measures of board characteristics employed in this study are Board size, Education qualification, Director Independence and Female direction proportion. Also this study employed Return on Assets as the measurement of the firm financial performance, and employed firm size as control variables. The data were analyzed and hypotheses were tested through descriptive statistics, correlation analysis and regression analysis by using SPSS. The findings revealed that, board size has negative significant influence on company performance. And also women direction proportion has negative and no significant influence on company performance. Director’s independent has positively not significant influence on firm performance. And also education qualification has positively not significant influence on firm performance. And also among control variable firm size has significant positive impact on financial performance.
BER ESTIMATION IN A CHROMATIC DISPERSION CO-OFDM DUAL POLARIZATION BASED SYSTEMS [PDF]
Ishiwu I. Jude,Yahya Adamu,Oguche D. Onoja,Jonathan Yakubu We present experimental demonstrations using both Coherent and Direct-Detection Optical-Orthogonal Frequency Division Multiplexing (DDO-OFDM and CO-OFDM) for the compensation of Chromatic Dispersion (CD) and residual dispersion in long-haul optical fiber networks. The analysis showed that CO-OFDM outperformed that of DDO-OFDM provided the same parameters were used throughout the experiments. Two model systems were developed, one with Phase Rotation Method/Constellation Adjustment Method (PRM/CAM) and one without. From the results obtained, it showed that the model with PRM outperformed one without PRM. Different modulation formats (Quadrature Phase Keyings and Quadrature Amplitude Modulations) were used in the simulations, the results obtained equally showed that the lower modulation schemes; QPSK and 4-QAM have a better BERs than the higher modulation schemes; 256-QAM and 512-QAM. At a high distance of about 1000 km, the 4-QAM systems outperformed QPSK, 256-QAM and 512-QAM system by a factor of 10-2, 10-4 and 10-5 respectively.
Integrated Adsorption–Coagulation and Naofiltration of Textile Effluent Using Three-stage Filtration Unit [PDF]
Vanitha Priya D, Arun Karthick S, Sudharsan K4, Arumugam P, Pandima Devi MK, Anuradha VTreatment of textile effluent using biomaterials extracted from the waste materials has gained attention nowadays.This research mainly aims to treat textile effluent csollected from the discharge unit using three-stage treatment process. Primary tank contains matrices made of coarse crab shell, luffa sponge and carbon pieces. Second treatment tank consists of magnetic composites made of activated carbon and chitosan. Combined adsorption-coagulation process is followed at the second under different optimized operational parameters such as pH, solute concentration, solvent concentration, temperature, etc. Tertiary treatment tank contains nanofibers made of HTCC where the final treatment and removal of micropollutant occurs. Physiochemical analyses of pre- and post-treatmented effluent at each stage of treatment are carried out to examine the quality of treatment tanks and the results are discussed.
AN ANALYSIS OF FACTORS AFFECTING COTTON PRODUCTION IN ZVISHAVANE: A CASE OF WARD 4 IN ZVISHAVANE DISTRICT [PDF]
T. Kumirai1A. T. Kugedera and F. Chimbwanda The main objective of the study was to determine the factors affecting cotton production in Zvishavane District in Midlands Province. Strategies to address effects of these factors were raised. Data was collected from April to June 2017 through the use of personal interviews, focus group discussions and questionnaires. Data was analysed using excel and Minitab 18 to obtain graphs and analysis of means. The results show that 66.7% of the participants were males, 43.3% planted cotton on 1-2 hectares with 23.4% grow cotton on above 4 hectares. The results also showed that factors affecting cotton were significantly different with p = 0.011. Thirty farmers indicated that technology is the major factor which affects cotton production in Zvishavane. Transport and pests and diseases were indicated as major problems faced by cotton farmers with 33.3% and 22.2% indicated these problems respectively. The results show that there is significant different between problems faced by farmers with p = 0.041. Interviewed participants also highlighted strategies which can be used to counteract effects of factors affecting cotton production and these strategies were not significantly different with p = 0.773. Most farmers interviewed (70) indicated the need for farmer training to acquired knowledge of cotton production. The government is recommended to act on addressing factors such as marketing and prices of inputs by setting price floors and ceilings.
Contribution of Human and Capital Toward Regional Eco-nomic Growth of Garut District of West Java Province of Indonesia [PDF]
Achmad Rizal, Isni Nurruhwati This article presents the analysis of the contribution of human capital growth and capital growth to regional economic development of Garut district. Multiple regression Analysis by OLS model is applied to know the contribution of human growth variable and capital growth variable. While to know influence a number of variables about contribution to Garut Regional economic is applied by data times series from the year 1986-2016. This study shows that, human capital growth contribution negatively and insignificantly to the growth of the gross domestic regional product and capital growth has positively and significant influence on Garut Regional economic growth.
INVESTIGATING CLIMATE CHANGE IMPACT ON STREAM FLOW OF BARO-AKOBO RIVER BASIN CASE STUDY OF BARO CATCHMENT [PDF]
Shimelash Molla,Tolera Abdissa,Tamene Adugna, (DR.ING)In recent decades changes in climate have caused impacts on natural and human systems on all continents and across the oceans. Impacts are due to observed climate change, irrespective of its cause, indicating the sensitivity of natural and human systems to changing climate. One of the direct impacts of this climate change is on water resources development and indirectly for agricultural production, environmental quality and economic development which will lead again to difficult conditions for Human to live in. The objective of this thesis is to assess the impact of climate change on the stream flow of Baro watershed which is the major tributary of Baro-Akobo basin, Ethiopia. The soil and water assessment tool (SWAT) model was used to simulate the stream flow using the meteorological data of thirty one years from 1986 to 2016. The model was calibrated for a period of sixteen years from 1990-2005 and validated for the observed data for eleven years from 2006-2015 and shows a good agreement with R2 = 0.90 during calibration and R2= 0.93 during validation whereas NSE=0.66 during calibration and 0.61 during validation. Hypothetical climate change scenarios of precipitation from -20% to +20% at 10% interval and temperature change from 2oC ,and 3oC for the period of 2050s and from 3.5oC to 6oC at 1.5oC interval for the period of 2080s under RCPs 8.5 was taken based on the IPCC 5th assessment set for African countries. Results of this procedure show the sensitivity of stream flow to climate variability. For example, a change of precipitation from -20% to +20% for constant temperature of 2oC gives a reduction of stream flow by around 11% .Beside this, for a constant precipitation of 0% and variation of temperature from 2oC to 3oC there is reduction of stream flow by average of 12.7%. This shows that the Baro Catchment will be more sensitive to the average increase in temperature than to the average decrease in rainfall, which shows the role of evapotranspiration in the water cycle. Overall, the result suggest, a decrease in stream flow of 12.73% for the period of 2050s (i.e.2046-2065) and 15.56% by the end of the 21st century (2080s) as a consequence of decreasing rainfall of -20% and increasing temperature of 6oC Scenarios (i.e. the worst scenarios).
COMPARATIVE ON STRENGTH VARIANCE OF CEMENT / LIME WITH COSTUS AFER BAGASSE FIBRE ASH STABILIZED LATERITIC SOIL [PDF]
Charles Kennedy, Letam Leelee Prince,Kelechi OkwulehieThis study investigated and evaluated the engineering properties of an expansive lateritic soil with the inclusion of cement / lime and costus afer bagasse fibre ash ( locally known as bush sugarcane fibre ash(BSBFA ) with ratios of laterite to cement, lime and BSBFA of 2.5% +2.5%, 5.0% + 5.0%, 7.5% + 7.5% and 10% + 10% to improve the values of CBR of less than 10% and termed poor on remarks required subgrade and strength fo constructional works. Compaction test results of maximum dry density (MDD) and optimum moisture content (OMC) of soil at natural state of 100%, soil + cement + BSBFA and lime + BSBFA treated lateritic soil with inclusion of soil percentage ratios to cement ,lime and BSBFA of ratios of cement / lime and (BSBFA). MDD of 0% at 1.803KN/m3 increased to 1.860KN/m3 (laterite + cement + BSBFA) and 1.803KN/m3 and 1.838KN/m3. (laterite + Lime + BSBFA ) with 1.196% higher of cement combination difference. OMC values of clay / laterite + cement + BSBFA increased from 11.79% to 14.02% (cement) and 11.79% to 12.405% (lime) with 18.91% higher of cement and BSBFA treated laterite. CBR results of laterite + cement / lime + bagasse fibre ash (BSBFA) treated laterite soil increased from 9.8% to 35.3% and to 32.2% respectively, with 9.6% higher strength of cement treated, both showed tremendous strength increased at optimum ratio of 85% + 7.5% + 7.5% of soils + cement / lime + BSBFA. Results of UCS of laterite + cement / lime + BSBFA treated soil, increased from 155kPa to 984kPa and 299.1kPa respectively with 228.9% higher of cement to lime combinations at optimum inclusion percentage of 85% (laterite) + 7.5% ( cement / lime) + 7.5 (BSBFA). Beyond this specified percentage combination, crack was noticed and strength. Results of soil + cement / lime + BSBFA treated soil IP decreased from 22.8% to 19.5%.and 15.8% , with higher value by 23.42% in cement treated to lime. The entire results showed both cement and lime with BSBFA showed tremendous strength increased with cement treated at the peak in comparison.
PHYSICAL ACTIVITIES AND BODY MASS INDEX (BMI) IN URBAN ADOLESCE [PDF]
Md Haroon-Or-Rashid,Md Monowar Hossen Patwary, Dr. Syed Mohammad Faruk, Dr. Ahmed Imtiaz, Md Tariquzzaman Adolescent population in the world about 1200 million persons at the age of 10–19 years and about 19% of the total population of the world faces a series of serious nutritional challenges in developing country. Childhood obesity and physical inactivity are increasing in both developing and developed countries although at different rates. The underlying plausible hypothesis in the development of obesity is that the feedback from energy expenditure to appetite may be weak at low levels of physical activity and that sedentary lifestyles, therefore, favor positive energy balance and weight gain . According to world health organization (WHO), a school-aged youth should accumulate at least 60 minutes of moderate to vigorous intensity physical activity every day to ensure healthy development. It is estimated that less than one-third of young people are sufficiently active to benefit their present and future health and wellbeing. This decline is largely due to increasingly common sedentary ways of life like fewer children walk or cycle to school and excessive time is devoted to watching television, playing computer games and other sedentary activities. School-based physical activities have also been decreasing. Bangladesh is one of the poorest countries, with over a 150 million population and densely populated countries of the world (881/sq km), and about 60 million people (40%) live below the poverty line and 34.6% currently lives in the urban area. There are about 27.7 million adolescents aged 10-19 years of age in Bangladesh, which makes up about one-fifth of the total population. Adolescence is a crucial part of their life.
Increased Dissolved Oxygen On Cultivation of Nilem (Osteochilus sp.) With the addition of Aerator Diffuser [PDF]
Heti Herawati, Izza M Apriliani, Lantun P Dewanti, Achmad RizalCharacteristics of water quality is dynamic or fluctuating easily, one important factor that needs to be maintained is dissolved oxygen (Dissolve Oxygen). Handling is done to keep the dissolved oxygen concentration is the addition of aeration. Aeration added to the aquaculture container in this study is a diffuser aerator that has the characteristics of easy maintenance, high oxygen transfer efficiency, and economical. The purpose of this research is to know the effect of diffuser aerator to the increase of dissolved oxygen at different density of fish nilem. The treatments were A treatment (50 fish/m3), B (75 fish/m3), C (100 fish/m3) and D (125 fish/m3). This research was conducted in February - March 2018 at Natural Feed Farming Laboratory Faculty of Fisheries and Marine Sciences Padjadjaran University. The method used is experimental method by using descriptive analysis of komperatif. The results showed that the use of Diffuser Aerator has an influence on dissolved oxygen on the cultivation of fish nilem that is ranging from 6.0 - 7.9 mg/L higher than using ordinary aeration and 100 fish stocking stock is the best amount during the study with a lifetime of 86% with fish population of 86 fish.
EFFECTS OF RADIO REFRACTIVITY GRADIENT AND K-FACTOR ON RADIO SIGNAL OVER IBADAN, SOUTH WESTERN, NIGERIA [PDF]
Aremu Olaosebikan Akanni., Oyinkanola Lateef O. A., Akande Ademola., Azeez Waheed AdebayoDetermination of radio refractivity, refractivity gradient and k-factor are very significant parameters in planning radio communication links. This study presents an estimation of radio refractivity gradient and k-factor so as to determine the effects of these secondary weather parameters on radio signal strengths over Ibadan (7.4546oN, 3.8919oE). Two years atmospheric primary weather parameters data from Nigerian Meteorological agency (NIMET) was used to calculate the refractivity, N, refractivity gradient, G, and k-factor at different heights from the ground level, the heights considered are; 50, 100, 150 and 200 m. The results obtained indicated that the average radio refractivity, N, was higher during the rainy season due to the rise in the atmospheric moisture content in the region and the value of N also decreases with height. The mean radio refractivity gradient and the average k-factor obtained were -50.417 Nunit/km and 1.5285 respectively. The value of k-factor obtained is greater than the global standard value, 4/3. In this case, super-refraction occurs in this study area and the radio signal propagate abnormally towards earth’s surface which might leads to signal interference over this region of study. An empirical relationship for predicting further the radio refractivity at different heights over this region of study has also been developed.