Performance evaluation of some rain attenuation prediction models at coastal locations at 12 and 40 GHz

This work concerns the evaluation of the performances of some selected rain attenuation models at two different locations in Lagos, Nigeria at 12 and 40 GHz. Scarcity of rainfall data in the tropical regions resulted in abysmal research efforts into the causes and solutions to satellite signal outages, this was further exacerbated by the convective tropical rain precipitations. The globally adopted ITU-R model, had been declared unsuitable for predicting rain attenuation in the tropics by several researchers in the literature. Two-year (January 2016 to December 2017) local rainfall data were sourced from the Nigerian Meteorological Services (NIMET) for two coastal stations (Ikeja and Oshodi). Rain attenuation exceeded for rain rate at 0.01% of the time, was computed after the 1-hour rain rate integration time which was sourced from NIMET was converted to 1-minute integration time. Attenuation exceeded for other percentages of time were also obtained using statistical interpolation and extrapolation methods. The collected data were tested with ITU-R, SST, SAM, DAH and Silva Mello et al. For Ikeja at 12 GHz, the SST was observed to closely match the measurement attenuation at 0.01%≤p≤1% of time exceeded; closely followed by Silver Mello. For Oshodi also at 12 GHz, SST intersected with the measured attenuation at 0.01%≤p≤0.03%, and p=0.1% of time. However, at 40 GHz, all the prediction models performed poorly by underestimating the measurement for Ikeja, although SST showed the best effort. The SST model matched the measurement, especially at p=0.03% and p=0.5% for Oshodi at 40 GHz, closely followed by Silva Mello which matched the measurement at p=0.05% and p=0.1%, while ITU-R, SAM and DAH largely underestimated the measurement. The SST was therefore affirmed the overall best performed rain attenuation prediction model for both stations at both frequency bands; closely followed by the Silva Mello. ITU-R, SAM and DAH on the other hand performed poorly. The findings arising from this work could present useful information to satellite equipment designers and manufacturers, while at the same time ensuring that service providers conform to the required service level agreements

Evaluation of the impact of anthropogenic activities on wetland soil qualities: A case study of Isoko South Area of Delta State, Southern Nigeria

This research was carried out to evaluate the impact of dumpsite and farming methods (anthropogenic Activities) on wetland soil qualities. Soil samples were collected from three strategic locations in Irri and Uzere communities at Delta State of Nigeria, and a reference station (control) about 5 km away from the study site. The sampling was done at the end of the rainy season (September, 2020), when the flood water had started rescinding, at two soil depths (5 to 10 cm and 45 to 50 cm). The concentration of iron, nickel, copper and cadmium concentration of the soil samples were determined with the Atomic Absorption Spectrophotometer (AAS), according to procedures approved by ASTM International. Results obtained from the chemical analysis revealed irregular concentration and distribution of the heavy metals within the studied area. Regardless of the sampling depth, the highest heavy metal concentrations were observed around the active dumpsite. Ranking order of the heavy metals’ concentrations in all the sampling locations was Fe ˃ Cu ˃ Ni ˃ Cd. It was observed from the results that the profile concentrations of the heavy metals increased with an increase in the soil depth. Using the contamination factor to assess the heavy metals contamination of the wetland, the results showed that the area ranged from moderate to considerable level of contamination, while pollution load index reveled that wetland soils were moderately polluted with the heavy metals. In terms of the soil pollution, the overall results revealed that area closed to the wastes dumpsite (site 1) was heavy polluted with the heavy metals

Seedling performance of different provenances of selected indigenous tree species in Debub Ari District, Southern Ethiopia

Better understanding of variations in seed traits and seedling vigor in various populations of a given species is vital for appropriate nursery and tree planting technology. The main objective of this study was to identify better provenance for indigenous trees by testing seed germination and seedling traits. Seeds of six indigenous trees (Vachellia abyssinica, Vachellia seyal, Faidherbia albida, Balanites aegyptiaca and Terminalia laxiflora Engl.) were collected from different geographic areas. One hundred (100) polyethylene pots (20 cm height and 12 cm diameter) were filled with 2:1:1 ratio of local, forest soil and sand composition for seedlings. A Complete Randomized Design (CRD), 5 x 4 polyethylene pots in four replications of 20 polyethylene pots for each provenance was designed in the nursery and the provenances for selected species. Different early growth performance parameters were measured for each tested provenance. All collected data were analyzed by using ANOVA while the least significance difference was computed for mean separation. The seedling performance of Vachellia abyssinica and Vachellia seyal were significantly varied among the provenances. Vachellia abyssinica from Butajira provenance had the highest mean values across all the studied parameters. Except height, Kako provenance had the highest mean values across all the early performance parameters of Vachellia seyal. Seedling performances of Faidherbia albida in the nursery was significantly varied among the provenances except for root collar diameter. Provenance from Wondo Genet had the highest mean values of germination percent and comparable leaf numbers with provenance from Hawassa. It can be concluded that the observed patterns of variation will have the implication for genetic resources conservations and tree improvement. Accordingly, Butajira and Kako provenances could be taken as a good source of seed collection for Vachellia abyssinica and Vachellia seyal, respectively. Wondo Genet and Hawassa provenances could also ensure the provision of planting materials of Faidherbia albida for farmers. Further progeny tests in the field should be undertaken for a longer period to obtain definitive recommendations for early selection

Barriers to solving environmental problems caused by building constructions in Nigeria: Trudgills’s framework

Our environment has been compromised through unwise and unplanned use of land, air, and water exacerbated by population increase, science and technology so much that some areas in Nigeria no longer support life as it ought to. Continuous impacting negatively on the environment to afford us the luxury building construction can afford, eventually leads us to short term and long term economic and environmental grief. At various forum, conferences and literatures, scientists have raised this concern. Not only have concerns been raised, solutions and recommendations were proffered, yet the problems linger. This work adopted Trudgill’s a range of possible barriers to a better environment occasioned by many facets of human activities on earth, ranked the barriers according to Likert’s scale to determine which of these barriers hinders solving environmental problems caused by building constructions. Data from building and construction practitioners were collected using a questionnaire on masons, architects, land surveyors, structural engineers and clients/contractors through semi-structured. The result indicates that lack of political will and political ideology to implement the solutions proffered and the recommendations made in various researches was ranked as the first or major barrier to solving environmental problem caused by building constructions followed by economic insufficiencies. The third barrier according to the study was technology related barrier. The study recommends green building initiative by government and all stake holders in the construction sector

Grain size analytical and geochemical data of sediments from Ishakare and Alatan streams in Akungba-Akoko, Southwestern Nigeria

The identification of anomalous elemental concentrations and the prediction of their dispersal pattern play a key role in geochemical exploration. Stream sediments are important focus in this aspect. Nine (9) sediment samples collected from Ishakare and Alatan Streams in Akungba-Akoko were subjected to grain size and inorganic geochemical analyses in order to determine their grain sizes distribution, travel distances, elemental concentrations and origin. Results of grain size analysis show that streams sediments are mostly medium-grained, poorly-moderately sorted and ranged from fine to strongly coarse skewed suggesting that they have been transported relatively not too far away from their sources under high to low energy. SiO2 is a dominant major oxide with concentration values ranging between 64.81 and 71.59 wt.% with a mean value of 68.07 wt.%. Abundance of Al2O3 indicates that samples are from Aluminum-rich source bed rock. The weights of Fe2O3 and TiO2 also point to gneissic rocks as a probable source. Generally, concentrations of trace elements were found to be low indicating that the contamination statue of the sediments ranges from unpolluted to moderately polluted

Geo-electric assessment for groundwater potential at permanent site of Waziri Umaru Federal Polytechnic, Birnin Kebbi, Kebbi State North Western, Nigeria

Vertical Electrical Soundings (VES) afford fast and economical measurements used in geophysical exploration. VES was used for groundwater exploration at the permanent site of Waziri Umaru Federal Polytechnic, Birnin Kebbi. Eighteen (18) Vertical Electrical Sounding (Schlumberger array, maximum AB/2 distance 100 m) were performed, data were acquired using ABEM terrameter (SAS 300c), to determine the geoelectric units in the subsurface stratigraphy as well as to delineate groundwater potential in the area via electrical resistivity soundings. Field data collected was analyzed using computer software (IPI2win) which gives an automatic interpretation of the apparent resistivity in ohm-meter. Data was interpreted in terms of the resistivity and thickness of subsurface layers. Results indicates that three to five (3-5) distinct layers in the study area namely; top soil which is mainly sand, clayey sand/loose sand, sandy clay/fine sand and clay unit were delineated. The result also revealed that water bearing formation exists in the third layer in some identified VES locations i.e VES 3, VES5, VES13 and VES14 with very good aquifers, with thickness and corresponding resistivity values of 40.5, 37.5, 45.8, 60 m and 173, 148, 222 and 432 Ωm respectively. The electrical resistivity data, therefore gives reasonable accurate results that can be used to understand stratigraphy and sedimentary configuration in ground water exploration.

Environmental and health risk implications of air quality in the vicinity of the Port Harcourt Airport road dumpsite

This study examines environmental and health risk implications of air quality in the vicinity of the Port Harcourt airport road dumpsite. The study objectives are to determine air quality in the vicinity of the Port Harcourt airport road dumpsite of the municipal solid waste, examine the health risk implications of air quality in the study location, ascertain the environmental implications of the air quality in the vicinity of the dumpsite, and identify if there are variations in air quality in the different sections in the study location. Air quality was determined using standard operating procedures where samples were collected at the dump, 250 m and 500 m away from the dumpsite. The samples were collected in the morning, afternoon and evening hours of the same day. The samples collected from these locations were taken in-situ amongst which are (Co2, CH4, O2, Co, H2S, PM-2.5, PM-10, Ni, Cr, Temperature and RH). Survey questionnaire was administered, in order to complement the field results. Three hypotheses were also tested using ANOVA and the Chi-square analytical tool. The findings of the study show that Nickel and Chromium amongst other parameters were above the WHO standard limits. Therefore, the quality of air within the vicinity of the dumpsite is considered polluted. Consequently, URTI and skin rashes are the common ailments that are prevalent in the area of study. Thus, the municipal solid waste dumpsite constitutes both environmental and health implications to the human population within the vicinity of the Port Harcourt airport road dumpsite. In this regard, this study recommends that the citing of waste dump should be done in line with standard regulations and prohibits the development of residential settlements within 3 km radius from any dumpsite.