Improving rheological properties of Gambe clay for drilling fluid application using fermentable polymers

There are abundant bentonitic clay deposits in Nigeria. However, it does not meet commercial standard for drilling mud formulation, because it is composed of calcium montmorillonite. Therefore, there is need for the clay to be enhanced and polymers have been identified as enhancement agents. The work was aimed at improving the rheological properties of Gambe clay for drilling fluid formulation using the fermentable polymers (xanthan gum, locust bean gum and tamarind seed gum). The clay was obtained from Gambe town in Adamawa State, Nigeria. The clay was beneficiated for quartz removal and chemical beneficiated with 6 wt% of Na2CO3. The mineral composition and the cation exchange capacity of the clay was determined using X-ray diffraction analysis and ammonium acetate saturation method, respectively to find out its quality for drilling mud formulation. Drilling mud was formulated by mixing of 22.5 g of the clay to 350 ml of water with a high speed mixer to obtain a homogenous mixture. The polymer enhancers were also added to the mixture. The effect of the fermentable polymer at different concentration on the rheological properties of the formulated drilling fluid was investigated employing FANN 35SA viscometer. It was found that 0.93 wt% of the tamarind seed gum, locust bean gum and xanthan gum in the formulated drilling fluid enhanced the yield point from 0.72 Pa to 7.2 Pa, 12.48 Pa and 16.36 Pa, and the gel strength from 0 Pa to 8.35 Pa, 10.44 Pa and 68.92 Pa of the formulated mud respectively. The mud enhanced with 0.80 wt% of the enhancers had high rheological properties than imported clay.Keywords: Drilling mud, Gambe clay, tamarind seed gum, locust bean gum, rheological propertie

Growth differentiation factor 9 gene variants in Sudanese desert sheep ecotypes

Certain variants in the growth differentiation factor 9 (GDF9) gene have major effects on the ovulation rate in sheep. The aim of this study was to analyse GDF9 variability in the Sudanese desert sheep ecotypes Ashgar, Dubasi and Watish, and to test identified variants for association with litter size. For this purpose, ewes of these ecotypes with litter size records for at least two litters were sampled. The complete GDF9 exon 2 was sequenced in a total of 28 ewes. An additional variant in exon 1 (c260G>A) was genotyped by restriction-length polymorphism analysis in 97 ewes. Differences in genotype and allele frequencies of polymorphic positions between two groups differing in litter size (only a single lamb versus more than a single lamb) were tested for significance using Fisher's exact test. GDF9 exon 2 variants c.477G>A and c.721G>A and exon 1 variant c.260G>A were found to be polymorphic in all three sheep ecotypes. Exon 2 variants c.471C>T and c.978 A>G were polymorphic in at least one ecotype. No significant associations were observed between allele and genotype frequencies of identified variants and litter size. This suggests that GDF9 variants influencing ovulation are absent in these Sudanese sheep ecotypes, and therefore cannot be used to increase litter size within this population of sheep.Keywords: Ashgar, Dubasi, fecundity, litter size, ovine fertility, Watis

High Gain, Low Noise Cascode LNA Using T-Matching Network for Wireless Applications

This paper presents a high gain, low noise Cascoded LNA using T-matching network applicable for wireless applications. The amplifier use FHX76LP Low Noise SuperHEMT FET. The LNA designed used T-matching network consisting of lump reactive element at the input and the output terminal. The cascode low noise amplifier (LNA) produced gain of 18.5 dB and noise figure (NF) of 1.30 dB. The input reflection (S11) and output return loss (S22) are -11.5 dB and -12.3 dB respectively. The bandwidth of the amplifier recorded is 1.4 GHz.The input sensitivity is compliant with the IEEE 802.16 standards

Occurrence of mycotoxigenic fungi in poultry feeds at live-bird markets, Zaria, Nigeria

Contamination of poultry feeds with mycotoxin-producing fungi such as Aspergillus spp is a major threat to animal and human food. This study was conducted to determine the occurrence of aflatoxigenic strain of fungi in feeds, fed to birds in live-bird markets. Feed samples were collected from feeding troughs and feeder in cages of birds and were inoculated on Sabouraud dextrose agar and Czypeck dox agar. Of 300 feed samples, 283 yielded various fungal growth belonging to seven genera, four of them known to be mycotoxigenic. Aspergillus, Rhizopus, Mucor, Dermatophyte, Yeast, Fusarium and Penicillium, whose isolation frequencies were 78%, 6%, 5.67%, 2%, 2%, 0.33% and 0.33% respectively. The aflatoxin producing Aspergillus spp isolated were A. flavus, A. parasiticus and A. nomius 126 (42%), 27 (9%) and 3(1%) respectively. In conclusion A. flavus was the most frequently isolated, and it is a known aflatoxin producer. It is recommended that mycotoxin binders should be added to poultry feed to mitigate the effect of aflatoxin contamination of feed in live-bird market.Keywords: Aflatoxin, Aspergillus species, Feed, Live bird markets, Mycotoxi

Bayesian inference for linear regression under alpha-skew-normal prior [Pentaabiran Bayesian untuk Model Regresi Linear Prior Normal-Pencong-Alfa]

A study on Bayesian inference for the linear regression model is carried out in the case when the prior distribution for the regression parameters is assumed to follow the alpha-skew-normal distribution. The posterior distribution and its associated full conditional distributions are derived. Then, the Bayesian point estimates and credible intervals for the regression parameters are determined based on a simulation study using the Markov chain Monte Carlo method. The parameter estimates and intervals obtained are compared with their counterparts when the prior distributions are assumed either normal or non-informative. In addition, the findings are applied to Scottish hills races data. It appears that when the data are skewed, the alpha-skew-normal prior contributes to a more precise estimate of the regression parameters as opposed to the other two priors. - 2019 Penerbit Universiti Kebangsaan Malaysia. All rights reserved.Scopu

Pouzzolanicité de la cendre volcanique de Béni Saf

International audienceAfin d'évaluer l'influence d'une substitution partielle de ciment par de la cendre volcanique de Beni-Saf, des tests préliminaires rapides tels que la mesure de la conductivité électrique et du pH sur des suspensions, permettent une première quantification de la pouzzolanicité. Pour confirmer ces premiers résultats, des tests sur des mortiers avec substitution partielle du ciment par cette cendre ont été réalisés. L'influence sur les propriétés physico- chimiques des pâtes cimentaires est étudiée : mesure du début et de fin de prise, rhéologie de la pâte cimentaire, mais aussi le retrait des mortiers avec ou sans la pouzzolane. Les résultats montrent que la pouzzolane diminue le pH et la conductivité de la suspension du ciment. Elle ralentit la formation des hydrates et par là même, le début de la prise de la pâte cimentaire; ce qui favorise l'écoulement et la maniabilité du mortier et du béton. Coté négatif, la pouzzolane engendre un retrait plus grand que celui du mortier de référence. Les résistances mécaniques sont plus faibles aux courtes échéances mais après un mois de conservation, elles atteignent des niveaux similaires à ceux des mortiers sans cendre. Les résultats de cette étude confirment donc que l'utilisation de cette addition pouzzolanique est possible pour des utilisations compatibles avec un retrait non négligeable. Enfin, on peut noter que les essais par pH-métrie et mesures de conductivité des suspensions renseignent très rapidement sur les possibilités d'effets pouzzolaniques des fillers ajoutés au ciment

Growth and yield components of some groundnut (Arachis hypogaea L.) cultivars infected with blackeye cowpea mosaic virus

Blackeye cowpea mosaic virus (BlCMV) is a major virus, infecting legumes with attendant huge losses. Cultivation of resistant varieties is the most effective and sustainable control strategy. Therefore, some groundnut (Arachis hypogaea) cultivars were evaluated against BlCMV in Minna, Southern Guinea savanna zone of Nigeria. The experiment was conducted at the Teaching and Research Farm, Federal University of Technology, Minna. It was arranged as infected and uninfected using Randomised Complete Block Design (RCBD) with three replications. Groundnut seeds were sowed in the second week of August, 2015. Seedlings were inoculated by sap transmission at 10 days after sowing. Disease incidence, severity, growth and yield attributes were recorded. Data were subjected to analysis of variance (ANOVA) and means separated at p≤0.05 probability level. Disease incidence varied significantly p<0.05 from 28.3 to 60.3 % at one week after inoculation (WAI) and 44.7 to 100 % at 2 WAI. ICGV 91317 which expressed mild infection (symptom score = 2) at 9 WAI also exhibited the lowest leaf diameter reduction (3.6 %) at that growth stage. FDRF7-82 which had the lowest reduction in number of leaves per plant at 3 and 6WAI (10.7 and 9.6 %, respectively) also exhibited the lowest reduction in fresh haulm weight per plant (42.2 %). None of the cultivars exhibited consistent reactions, FDRF7-82 and ICGV 91317 had an appreciable combination of growth and yield attributes under BlCMV infection. However, these cultivars could be improved upon either through conventional or molecular breeding by coding with desirable genes. The cultivars which were adversely affected by BlCMV disease could so be improved genetically through appropriate gene introgression from the resistant cultivars.Keywords: Blackeye cowpea mosaic virus; disease incidence and severity; growth and yield; groundnu

Study of average seasonal variations of surface radio refractivity across some selected cities in Nigeria

The average seasonal variations of surface radio refractivity based on measurement of atmospheric pressure, temperature and relative humidity made across Yola (9o11' N, 12o30' E), Anyigba (7o 45' N, 6o45' E), Lagos (6o 27' N, 5o12' E), and Port-Harcourt (4o 48'N, 7oE) Nigeria, is reported. The measurement was made using wireless automatic weather station installed at the surface of each station under study. The study utilized three years of meteorological data measured from January 2010 to December 2013 to calculate the surface radio refractivity using empirical formula recommended by the International Telecommunication Union (ITU-R 453, 2012). The result shows that the average value of surface radio refractivity showed seasonal variations with high values during the rainy season and low values during the dry season with an increase in the value of surface radio refractivity of 242N units at Anyigba station to a maximum value of 384-N units at Lagos station. The result also shows that climatic condition is the force behind the seasonal variations of surface radio refractivity in all study stations.Keywords: Refractivity, Temperature, Atmospheric pressure, Relative Humidit

Desain Dan Implementasi Alat Pengendali Suhu Secara Otomatis Pada Rumah Burung Walet

Now, the development of microcontrollers get faster and more and more in demand as a control system. Even now, it has been in the form of a samller module, complete, and practical in application. This analysis aimed to design and implement an automatic temperature control system application in iot-based swallow birdhouse. Application of humidity and air temperature monitoring is equipped by components such as NodeMCU ESP8266, DHT11 sensor, 2x16 LCD, 12C LCD, and several supporting components. The design and realization of monitoring application in swallow birdhouse cultivation that came from the experiments, while the support for this analysis was obtained from several sources like books, internet, and literature. This application uses a microcontroller that is equipped with an ESP8266, a Wi-Fi module that can be connected via internet network. The working system of this tool is to detect the temperature and humidity in swallow nests using DHT11 sensor which is processed by NodeMCU, then the monitoring data is monitored and controlled through the interares platform on the internet using Wi-Fi as a medium for connecting the device by a smartphone or PC. The result of this study were carried out by comparing the hygrometer thermometer with the monitoring tools that have been made and produce the smallest temperature error value of 0,3% and produce the smallest error 0% humidity with an average error value that is not large