A Comparative Analysis of the Rebound Hammer and Ultrasonic Pulse Velocity in Testing Concrete

This work presents a study on the comparison between some non-destructive testing tech-niques (Rebound Hammer and Ultrasonic Pulse Velocity). Tests were performed to com-pare the accuracy between the rebound hammer and the ultrasonic pulse velocity methodin estimating the strength of concrete. Eighty samples (cubes of 150 x 150 x 150) wereprepared using two mix designs of 1:2:4 and 1:3:6 with a constant w=c ratio of 0.45 andwere tested at 7, 14, 21 and 28 days. The slump test was between 62 - 78mm. The resultsobtained from the non-destructive testing methods were correlated with the compressivestrength results which showed that a higher correlation existed between the Rebound Ham-mer and the compressive strength than the Ultrasonic Pulse Velocity. The rebound ham-mer readings had a correlation coecient of 0.794 while the ultrasonic pulse velocity hada correlation coecient of 0.790 for the 1:2:4 mix and the rebound hammer readings for1:3:6 was 0.783 and that for the ultrasonic pulse velocity was 0.777. Statistical analysisof the results obtained showed that there was no signicant dierence between the meansof the two methods for both mix at a 0.05 level of signicance

Suitability of Saw Dust Ash-Lime Mixture for Production of Sandcrete Hollow Blocks

The use of saw-dust ash (SDA) mixed with 45% slaked lime for production of sandcrete hollow blocks was investigated. The aim was to determine the percentage SDA lime and water-cement ratio that would give the 28-day maximum strength. Saw dust was burnt and the ash sieved using a 150 micrometer sieve. The ash mixed with 45% slake lime was used to partially replace ordinary Portland cement (OPC) in various proportions. Fifteen blocks for each proportion were moulded using the mix of 1:8 and water-cement ratio of 0.50. Sprinkling of water on the blocks commenced after three days. The blocks were cured by complete immersion in water at room temperature. Three blocks were tested for strength at each of the ages of 7, 14 and 28 days for each proportion of OPC/SDA-lime. The 90:10 (cement: SDA-lime) proportion which gave the highest strength was further investigated for various water-cement ratios. It was concluded that for a mix of 1:8, 10% replacement of OPC by SDA-lime gave the maximum strength at water-cement ratio of 0.55 and was recommended for the production of sandcrete hollow blocks. The blocks should be used for low-income housing and non-load bearing walls

Geochemical investigation of gold and chalcophile minerals of Rawayau Area Katsina State, Nigeria

This present study investigated the Gold and Chalcophile mineralisation potentials of the Rawayau area in Northwestern Nigeria. The aim of the investigation is to delineate the likely Gold and Chalcophile mineralisation occurrences in the study area so as to aid further exploration studies that will identify Gold rich targets worth investing resources for detail exploration project before mining. To achieve this, 17 samples (7 rock samples and 10 sediments) were collected and subjected to laboratory analysis at the National Geologic Survey Agency (NGSA) in Kaduna. The geochemical study showed that the Au concentration ranged from below detection level (bdl) to 0.09ppm in the rock samples, while ranging from 0.013ppm to 0.137ppm in the sediments. Ag concentration ranged from 0.37ppm to 0.97ppm with in the rock samples, while ranging from 0.088ppm to 0.229ppm in the sediments, thus showing a higher concentration in both rock and sediments than Au. Significant positive relationship was observed between Ni, Cr, Cu, Mn, Fe, Zn and Co from the correlation analysis. It also revealed a subsurface increment of Gold and Chalcophile concentration of Nickel, Copper and Zinc with higher concentration of Nickel, Copper, Zinc, Manganese, Chromium and Lead in comparison to Gold and Silver. The study concludes that the Rawayau area holds much prospects for Gold and other minerals. It is suggested that further exploratory studies be carried out so as to pave way for the commencement of mining activities in the study area”

Comparative Study of Patients' Adherence between Hospital-based and Communitybased Treatment for Multidrug Resistant Tuberculosis (MDR-TB) in Kaduna State,

Background: Multidrug-Resistant Tuberculosis (MDR-TB) epidemic is threatening the global control of TB. It is driven by the programme, health system  and patient related factors. This study aimed at comparing the level of adherence to treatment among MDR-TB patients treated in hospital-based and  community-based models of care. Methods: This was a comparative cross-sectional survey conducted in 2019 with mixed methods of data collection. The study population were 360 MDR-  TB patients treated in hospital-based and community-based facilities in Kaduna between 2013 and 2018. Questionnaire, FGD and KII guides respectively  were the quantitative and qualitative data collection tools used. Statistical Package for Social Sciences (SPSS) version 25.0 was used to analyze the  quantitative data while thematic analysis was used for analysing qualitative data. The quantitative results were presented in descriptive statistics with  level of significance set at p<0.05 and the qualitative results were presented as prose. Results: The majority were males in the community-based 135 (71.8%) and the hospital-based model 126 (73.3%), with median (IQR) ages of 33 (27-40)  years and 34 (27-43) years respectively. Adherence to treatment was significantly higher among patients in hospital-based (64%) compared to  community-based (36%), (p 0.001). Availability of family and community support encourages adherence while lack of food supplies, dissatisfaction with  services and drug side effects were factors against adherence to treatment. Treatment success rate was similar in both models. Conclusion: Adherence was better among patients initiated on treatment in the hospital-based model. Adherence should be strengthened in the  community-based model by regular counselling and health education

Provenance Studies of Alluvial Tin Deposits in Parts of Ropp Younger Granite Complex, North Central Nigeria

The study area in this research is within the Ropp Complex, part of the Nigerian Mesozoic Younger Granite province. The study aims to interpret the depositional environment and establish the provenance of the alluvial cassiterite deposits in the study area. Boreholes/mining pits were logged for this study, and stanniferous sandstone samples were collected, which were used for textural and mineralogical studies. The mineral assemblages documented in the samples include ilmenite (3% to 27%). Cassiterite (2 to 14%), Zircon (2 to 16%), magnetite (0 to 17%), tourmaline (5 to 11%), rutile (2 to 8%) and monazite (2 to 7%).The ZTR Index calculated from the result of heavy minerals analysis for the selected pieces is 59%. Mineralogical studies revealed that quartz is the most dominant detrital mineral averaging about 93-99%, indicating that the stanniferous sandstones are compositionally matured and have experienced a high degree of chemical weathering. The quartz grains have grain sizes ranging from coarse to very coarse. They are poorly sorted, sub-angular to sub-rounded, with low sphericity. This also indicates a closeness to the source and textural immaturity. The occurrence of relatively very few feldspar grains suggests a slow sedimentation rate, very high rate of chemical weathering and composition maturity. The bivariate plots, univariate grain size parameters and probability plots, and the absence of fossils and trace fossils suggest deposition in a fluvial environment. The results of the granulometric analysis indicate that the study area's stanniferous sandstone was deposited in a fluvial environment by a low-energy fluvial (river) depositional system and the deposition in proximal (close to the source). This study suggests that the Basement complex and Younger Granite are the sources of the stanniferous placer deposits

A sensitivity analysis of a gonorrhoea dynamics and control model

We formulate and analyse a robust mathematical model of the dynamics of gonorrhoea incorporating passive immunity and control. Our results show that the disease-free and endemic equilibria of the model are both locally and globally asymptotically stable. A sensitivity analysis of the model shows that the dynamics of the model is variable and dependent on waning rate, control parameters and interaction of the latent and infected classes. In particular, the lower the waning rate, the more the exponential decrease in the passive immunity but the susceptible population increases to the equilibrium and wanes asymptotically due to the presence of the control parameters and restricted interaction of the latent and infected classes.Comment: Journal of Mathematical and Computational Science, 202

Informed Consent among Hansen’s Disease Patients – A Nigerian Perspective

Background: Informed consent entails providing potential participants with adequate information needed to decide whether or not to participate in research. In Nigeria, Hansen's disease has remained a disease of public health importance. The associated stigmatization often renders patients vulnerable and prone to exploitation. The act of obtaining informed consent from these patients remain an issue of ethical importance. The study aimed to determine the willingness of Hansen's disease patients to give consent to use their data in the form of pictures, videos and/or oral interviews by a third party. Materials and Method: This descriptive cross-sectional study was carried out in three states in Nigeria; Ebonyi, Ogun and Cross River States. Data was collected from consenting participants using researcher-administered semi-structured questionnaires. Results: The study included 93 respondents with a mean (SD) age of 44.9 (20.1) years. The majority 57 (61.29%) of the respondents were farmers while the majority 67 (72.04%) attained primary education. A total of 26 (27.96%) respondents had suffered discrimination in the course of their disease. In their responses, 83 (89.2%) would allow the use of their pictures, 80 (86.0%) their videos and 86 (92.5%) their recorded oral interviews. Among those who would not give consent, the commonest reasons adduced were an intrusion into privacy and lack of trust. Conclusion: Though a majority of the patients would give consent for use of their data intrusion into privacy and lack of trust were major constraints for those not willing to give consent. Caregivers and stakeholders should put more effort into trying to win patients' trust before seeking informed consent

Climate Change Awareness and related Tree Planting Practices in a Rural Community in North-Western Nigeria

Background: Tree cutting is one of the causes of climate change and a common practice in Africa, a continent under significant threat from climate change. Therefore, climate change awareness and mitigation are vital to reducing its impacts in the region. Reforestation through planting of trees is an important carbon emission reduction strategy. This study assessed climate change awareness and related tree planting practices among household heads in a Nigerian rural community.Methods: A community-based descriptive, cross-sectional study was conducted in April 2019 among all household heads in Nasarawan Buhari community. An interviewer-administered questionnaire was used to collect data from the 104 household heads (or their representatives). Data was analyzed using SPSS (version 21.0) and statistical significance was set at p value of < 0.05.Results: The mean age of respondents was 40.6±12.6 years, and most of them (87.5%) were males. Half (50.0%) were aware of climate change, and their main source of information was radio (63.5%). Most (98.1%) used fire wood for cooking. Only a minority (27.9%) planted at least a tree in the year preceding the study. There was a statistically significant association between climate change awareness and occupation (p=0.038) but not with tree planting (p=0.827).Conclusion: The results indicated that only half of respondents were aware of climate change. There was high use of wood as cooking fuel with low tree planting. Tree planting was not associated with climate change awareness. There is therefore a need for continuous climate change education and mitigation campaign in the community

Parasitic weed incidence and related economic losses in rice in Africa

Parasitic weeds pose increasing threats to rain-fed rice production in Africa. Most important species are Striga asiatica, S. aspera and S. hermonthica in rain-fed uplands, and Rhamphicarpa fistulosa in rain-fed lowlands. Information on the regional spread and economic importance of parasitic weeds in cereal production systems is scant. This article presents the first multi-species, multi-country, single-crop impact assessment of parasitic weeds in Africa. A systematic search of public international and national herbaria and the scientific literature was conducted to collect all available data on the regional distribution, incidences and related yield losses of the most important parasitic weeds in rice. Herbaria specimens were geo-referenced and these coordinates were overlapped with rain-fed rice areas. Probabilistic diffusion waves of parasitic weeds were generated to derive most likely incidence values. Estimates from this spatial analysis were then combined with secondary data from the literature into a stochastic impact assessment model to generate a confidence interval of the likely economic impact per country and for sub-Saharan Africa as a whole. Rhamphicarpa fistulosa occurs in at least 36 African countries, 28 of which produce rice in rain-fed lowlands where this species thrives. Striga hermonthica is found in at least 32 countries, Striga asiatica in at least 44 and S. aspera in at least 17. A total of 50 countries have at least one of these three species of Striga, 31 of which produce rice in the rain-fed uplands where these species can be encountered. An estimated 1.34 million ha of rain-fed rice is infested with at least one species of a parasitic weed in Africa. Our stochastic model estimates that annual economic losses inflicted by all parasitic weeds exceeds, with 95% certainty, a minimum value of US $111 million and most likely reaches roughly US$200 million and increases by US $30 million annually. To reverse this trend and support small-holder rice farmers in Africa with effective, sustainable and affordable solutions for control, targeted investments in research, development and capacity building are required. The top-10 priority countries where such investments would probably have the highest return are Nigeria, Guinea, Mali, Côte d’Ivoire, Cameroon, Tanzania, Madagascar, Uganda, Sierra Leone and Burkina Faso