Current Journal of Applied Science and Technology

The paper presents the design of easy-to-use and sophisticated cutting tool insert clamping that is applied for turning tools. The simplified analytical calculation and von Mises stress fields obtained by Finite Element Method are provided. The technical solution of clamping screw is based on the specialized screw head that is of hexagonal-conical shape. The higher axial force in screw arising from the tightening, higher contact pressure clamping the cutting tool insert. The frictional force between screw head and the insert surfaces presses the cutting tool insert into its seating when tightening and helps to get out the insert when un-tightening. The design of clamping specialized screws gives the possibility to use them in integrated cutting tools with two or more cutting tool inserts.

Sago is a traditional food product of India made exclusively from fresh wet cassava starch. The engineering properties of different commercial grades of sago, developed by roasting and steaming process were investigated. The physical properties (moisture content, size, shape (sphericity), bulk density, particle density, porosity), functional properties (solubility index, swelling power, cooking time, cooking loss, oil absorption index), pasting and dynamic rheological properties were studied. The size of the roasted commercial and steamed nylon sago varied from 3.57 to 4.11 mm and from 2.50 to 5.88 mm, respectively. The shape (sphericity) of different grades of sago ranged from 0.63 to 0.86. The bulk density and particle density of the different commercial and nylon sago varied from 420 kg m^-3 to 800 kg m^-3. The swelling power (39.59 g/g) of the steamed nylon sago was high as compared to that of roasted sago. The steamed nylon sago showed a reduction in peak viscosity, breakdown and final viscosity as compared with the roasted commercial sago. A decrease in cooking loss with an increase in cooking time was noticed in the roasted commercial sago, whereas increase in cooking loss with increase in cooking time was noticed in the steamed nylon sago. The elevated peak viscosity value showed reduction in pasting temperature for both steamed and roasted sago. The different grades of sago gel behaved like a dilute solution due to increase in loss modulus over storage modulus. 

The aim of this study is to understand mechanisms that occur during leaching of alkali-resistant zirconium-containing glasses in acid and alkaline solutions. For this, we have developed 5 glass compositions: two alkali-resistant model glasses type CEMFIL, V1 (with zirconium and without heavy metals) and V2 (with zirconium and heavy metals), then three glasses of fly ashes V3 (without zirconium and with heavy metals), V4 (with 30 % of V3, zirconium and heavy metals) and V5 (with 60% of V3, zirconium and heavy metals). V4 and V5 are obtained using V3 as raw material and supplementing with SiO₂, ZrO₂ and Na₂O to give them alkali-resistant properties. Glasses leaching in acidic and basic medium led to an important basification from the first times of alteration at pH = 4 when a basification decrease is observed for solutions initially at pH = 13. Normalized elementary mass losses results showed that, glass alteration  is higher for low-calcium glasses (V1 and V2) and V4 and V5 glasses have the lowest elemental mass losses at pH = 4 and 13. SIMS profiles made on glass alteration films permitted to observe behaviour of  H, Na, Ca, Si and Zr elements after  28 days at pH = 4 and 13 and understand the different  dissolution mechanisms involved. SIMS profiles showed that a hydrated film develops on glass surface characterized by hydrogen enrichment and sodium depletion irrespective of the glass. These glasses are also characterized by a surface enrichment of zirconium (except V3 which does not contain zirconium) whatever the pH. Hydrated film thickness confirm that V1, V2 and V3 glasses are more altered than V4 and V5 glasses. These results are confirmed by ICP-AES leachate analysis.

Study of the terrestrial Background Ionizing Radiation levels of selected Oil Spill Communities of Delta State, Nigeria have been carried out using Digilert 200 and Radalert 100 nuclear radiation monitor and a geographical positioning system (Garmin GPSMAP 76S). The exposure rates of the five communities ranges from 0.016 to 0.030  at Jones Creek, 0.014 to 0.034  at Opuwade Community, 0.015 to 0.037   at Okpare community, 0.007 to 0.029  at OtuJeremi community and 0.011to 0.040  at Otor-Edo community. The obtained mean exposures rates were higher than ICRP standard limit of 0.013. The absorbed dose rates calculated ranged from 139.2 to 261 (Jones Creek), 121.8 to 259.8 nGyh^-1 (Opuwade Community), 130.5 to 321.9 nGyh^-1 (Okpare community), 60.9 to 252.3 nGyh^-1 (OtuJeremi community) and 95.9 to 348 nGyh^-1 (Otor-Edo community). The estimated annual effective dose equivalent varies from  0.21 to 0.40 , 0.19 to  0.45 , 0.20 to  0.49 , 0.09 to 0.39  and  0.15 to 0.53  for Jones Creek, Opuwade Community, Okpare community, Otu Jeremi community and Otor-Edo community respectively while the excess lifetime cancer risk calculated for Jones Creek varies from (0.75  to 1.40)  x 10^-3, Opuwade community (0.65 to 1.59 )×, Okpare community (0.70 to 1.73 ) x , OtuJeremi community (0.33 to 1.35)× and Otor-Edo community (0.51 to 1.87)×. All the mean values of absorbed dose, annual effective dose and excess lifetime cancer risk exceeded their recommended safe values. The results obtained in this work may not constitute any immediate health risk to the residents of the selected oil spill communities but long term exposure in the area may lead to detrimental health risks.

Background: Although several factors are known to influence the gestational age at booking, current knowledge indicates that the distribution of these factors could vary from one country to the other, and even within countries, the variation could exist between states. This study aimed to assess the prevalence, predictors and clinical correlates of gestational age at booking in southern Nigeria.

Materials and Methods: One hundred and fifty pregnant women who visited the study centres within the study period were evaluated for socio-demographic, clinical and biochemical characteristics associated with early and late ANC initiation using standard instruments and procedures.

Results: Fifty-six per cent (56%) of the pregnant women initiated ANC within the first thirteen weeks of gestation according to the WHO recommendation. Fewer numbers of previous pregnancies and births were significantly associated with early ANC initiation. Being of older age, (OR=1.52, C.I=1.318-1.956), fewer number of previous pregnancies (OR=2.2. C.I=1.923-2.511), low parity (OR=2.05, C.I=1.884-2.264), public servant (OR=1.52, C.I=1.316-1.753), higher educational attainment (OR=2.21, C.I=1.043-3.498) significantly increased the likelihood of early ANC initiation. Also, pregnant women who booked early had a lower incidence of anaemia, hypertension and gestational diabetes and better biochemical endpoints.

Conclusion: Some demographic variables and fewer numbers of pregnancies and births were significantly associated with a higher likelihood of early ANC initiation and vice versa. These factors should be considered in designing interventions to improve gestational age at booking among pregnant women in Nigeria and globally.

This study investigates the dynamic relationship between crude oil prices and stock market price volatility in Nigeria using cointegrated Vector Generalized Autoregressive conditional Heteroskedasticity (VAR-GARCH) model. The study utilizes monthly data on the study variables from January 2006 to April 2017 and employs Dickey-Fuller Generalized least squares unit root test, simple linear regression model, unrestricted vector autoregressive model, Granger causality test and standard GARCH model as methods of analysis. Results shows that the study variables are integrated of order one, no long-run stable relationship was found to exist between crude oil prices and stock market prices in Nigeria. Both crude oil prices and stock market prices were found to have positive and significant impact on each other indicating that an increase in crude oil prices will increase stock market prices and vice versa. Both crude oil prices and stock market prices were found to have predictive information on one another in the long-run. A one-way causality ran from crude oil prices to stock market prices suggesting that crude oil prices determine stock prices and are a driven force in Nigerian stock market. Results of GARCH (1,1) models show high persistence of shocks in the conditional variance of both returns. The conditional volatility of stock market price log return was found to be stable and predictable while that of crude oil price log return was found to be unstable and unpredictable, although a dependable and dynamic relationship between crude oil prices and stock market prices was found to exist. The study provides some policy recommendations.

The large demand for drinking water in Gbêkê region of Côte d’Ivoire is supplied from groundwater sources. This study investigated the groundwater physicochemical quality in Gbêkê region of Côte d’Ivoire based on preselected 24 boreholes. Groundwater evaluation index and focused principal components analysis were used to assess water physicochemical quality, which is a major factor for controlling the groundwater quality in term of drinking purposes. Most of the groundwater were acidic and presented low mineralization. Hydrochemical facies was Mg-Ca-Cl type. Groundwater quality index values ranged from 11.69 to 119.37. The analysis shows that about 96% of the samples were belonging to excellent quality water for drinking purposes. Focused principal components analysis suggests that groundwater quality was mainly related to geogenic (rock–water interaction) and anthropogenic source (agrogenic and domestic sewage) in the study area. It is expected that outcomes of the study will provide insights for decision makers taking proper measures for groundwater quality management in central Côte d'Ivoire.

Innovative plant breeding technology is an absolute necessity to enhance agriculture production in order to have an ambition of feeding nutritious food to the ever-increasing population. Current advances in CRISPR/Cas genome editing technology have led to effective targeted changes in most plants that promise to accelerate crop improvement. Here we discussed the discovery of CRISPR/Cas technology, associated manipulations for plant genome editing and its potential applications in the plant breeding. We emphasized mainly on the most essential applications of CRISPR/Cas genome editing in crop improvement, such as crop trait improvement (yield and biotic/abiotic stress tolerance), developments in optimizing gene regulation, strategies for generating virus resistance in plants, and the use of high throughput mutant libraries. Finally, the challenges and opportunities for plant breeding in precision agriculture and its bright future discussed.