Journal of Scientific Research and Reports

This research was conducted to investigate mortality using logistic regression (Models) for River red-gum (Eucalyptud camaldulensis Dehnh) in Afaka Forest Reserve, Kaduna, Nigeria. Stratified random sampling and proportional sampling allocation were used in selecting plots and individual trees for measurements. Data on live and dead trees were recorded, variables measured are diameter, total tree heights, spacing and age of the stands within the plots. Diameter at the breast height (DBH) was measured using diameter tape while Haga Altimeter was used in taking the total height of the sampled stands. The Data collected were divided into four portions. Three portions (75%) for model calibration adopting logistic regression model, 25% were used for model validation of logistic model generated.  Chi square test of goodness-of-fit, Negelkerke R², Cox and snell R² values were used for model evaluation. The positive regression coefficients (16.737, 49.266 and 1.992) showed by Dbh, Height and age (as independent variables) indicated positive future mortality effects on the stands; as the trees ages and increases in size and height, the chances of mortality will increase. At the present age and sizes of the stands the fitted model shows no significant relationship between the current age, height and size of the stands, as such the notion held by the management of the plantation that Eucalyptus cannot grow for many years and in large sizes is not true. There is therefore, need for periodic re-measurement of the stands to evaluate future effect of the variables (Age, Dbh and height) on mortality.

Concerns about the need for clean energy and the need to reduce green-house gases have led researchers and engineers to explore adoption of electric vehicle technology. Electric vehicles hold a promising future due to their efficiency, low maintenance cost and zero carbon emission. Unfortunately, due to metric range drawbacks associated with electric vehicles, large scale adoption of electric vehicles still remains relatively low. To solve this issue of range anxiety, optimal placement and sizing methods of electric vehicle infrastructure is essential. This paper presents a review of optimal siting of electric vehicle charging infrastructure. It discusses impacts of electric vehicle charging loads on the distribution network and how large scale electric vehicle penetration would affect the grid. Further, the benefits of electric vehicles on the distribution network as well as the integration of renewable energy resources are presented.

In this paper, we investigate the generalized fourth order Pell sequences and we deal with, in detail, three special cases which we call them as fourth order Pell, fourth order Pell-Lucas and modified fourth order Pell sequences.

A study of background ionizing radiation (BIR) levels to estimate organ dose rates and excess lifetime cancer risk in Unicem cement producing company, Calabar, Cross River state and Bua cement producing company, Okpella in Edo state have been carried out using Digilert 100 and Radalert-200 nuclear radiation monitor and a geographical positioning system (GPS) for GIS mapping of the area. The in-situ measurement of the exposure rate was between May, 2018 and June, 2019 at regular intervals. The average exposure rate of 0.023 mRh^-1 was measured at Unicem, Calabar and 0.027 mRh^-1 at Bua cement area, Okpella. The mean equivalent doses of 1.92 mSvy^-1 and 2.29 mSvy^-1 was recorded in Unicem and Bua Okpella respectively. The estimated mean outdoor absorbed dose rate value of 196.74 nGyh^-1 in Unicem and its environment while in Bua cement industry, Okpella, the value of 234.9 nGyh^-1 was obtained. The mean annual effective dose calculated was 0.24 and 0.29 mSvy^-1 for Unicem and Bua Okpella respectively. The mean excess life time cancer risk recorded in the areas 0.72 x10^-3 in Unicem area and 1.01 x10^-3 in Bua cement environment. The calculated dose to organs showed that the testes have the highest organ dose of 0.74 mSvy^-1 and 0.83 mSvy^-1 for Unicem and Bua Okpella areas respectively while the liver has the lowest organ dose of 0.08 mSvy^-1 and 0.11 mSvy^-1 for Unicem and Bua Okpella respectively. This study revealed that the exposure rate and all the radiological risk parameters exceeded their recommended safe values. The area of study is radiologically polluted and may be detrimental to human health for long term exposure.

Adsorbents such as metal-organic frameworks (MOFs), polymers, activated carbon (AC), and membranes are becoming prominent for CO₂, SO₂, H₂S and NH₃ capture and in some cases, storage. Using the standard adsorbent properties (SAPs) such as adsorption capacity, selectivity, permeability/permeance, regenerability and reusability, ease of functionability and tunability, thermal and chemical stability, suitable candidates for noxious gas sequestration can be determined. To foster the development and selection of a more efficient adsorbent, proper documentation of adsorbent performance in terms of SAPs is crucial. In this study, a critical review of metal-organic framework (MOF), polymer, activated carbon (AC) and membrane adsorbents was performed. Using the SAPs, an up to date comparative analysis was done to select the best performing adsorbents. The results of the comparative analysis were then used to categorize the adsorbents' suitability for pre-combustion and post-combustion applications. A perspective of future study on adsorbents for noxious gas sequestration was also presented.