Federal College of Education, Zaria

As a result of increasing environmental concerns/legislative pressure for dumping of non-biodegradable plastics in landfills and rapid increases in the cost of petroleum, the development of “environmental friendly” materials has attracted extensive interest. Recently, bioplastics are one of the most innovative environmental friendly materials developed. This review paper is intended to provide information about alternative to conventional plastics for the betterment of earth environment. They have some advantages such as lower carbon footprint, independence, energy efficiency, and eco-safety. For the sustainability, recycling systems and production technology may be developed for bioplastics and by-product should be used for their production. It is concluded that the use of bioplastics will help in sustainability and national development thus, making the environment less overwhelmed with greenhouse gases and reduction of waste biomas. And finally recommended by the reviewers that use of biomas for plastics production should be embraced especially those found to be biodegradable and use of petroplastics be incapacitated.

The prime conditions for the removal of Cu (II) and Pb (II) onto defatted papaya seeds (DPS) from aqueous solution were studied. The effects of three adsorption variables (adsorbent dosage, shaking speed as well as initial concentrations) were investigated using central composite design (CCD) which is a subset of response surface methodology (RSM). Quadratic models were developed for both Cu (II) and Pb (II) percentage removals. The optimum adsorption conditions obtained were adsorbent dosage of 0.30 g, shaking speed of 180 rpm as well as initial concentration of 150 mg/L with desirability of 0.987. The predicted and experimental values obtained were 96.65% and 97.55% for Cu (II) as well as 98.07 and 99.96% for Pb (II), showing good agreement between the experimental values and those predicted from the models with relatively small errors which were only 0.89 and 1.89, respectively. Langmuir isotherm model was found to be the best fit for the equilibrium adsorption data of both Cu (II) and Pb (II) on DPS giving rise to monolayer adsorption capacities of 17.29 and 53.02 mg/g respectively.

Antimony telluride (Sb2Te3), a layered semiconductor material, is considered a promising absorbing material for a high-performance optoelectronic device within broadband wavelengths because of remarkable features like strong optical absorbance and the narrow direct band gap. In this work, based on the first-principles approach, we investigate in detail the structural, electronic and optical properties of the hexagonal Sb2Te3 compound. The structural and electronic properties were computed using the first-principles approach, treating exchange–correlation potential with generalized gradient approximation (GGA) within density functional theory (DFT). Furthermore, for accurate prediction of the band gap, we go beyond DFT and calculated band structure using GW correction. The optical properties, namely, imaginary and real parts of complex dielectric function, absorption coefficient, refractive index, reflectivity, extinction coefficient, electron energy loss function and optical conductivity are performed by quasi-particle many-body perturbation theory (MBPT) via Bethe-Salpeter equation (BSE). The computed structural parameters are in good agreement with available experimental data. The obtained quasi-particle (GW) correction band structure show the semiconducting character of Sb2Te3 material with a direct band gap Eg of 0.221 eV, in agreement with previously reported value (Eg = 0.210 eV) while the projected density of states indicates (PDOS) that the p-orbital of Sb and Te atoms are responsible for material properties near the Fermi level. To our knowledge, our first reported calculations of optical properties, with the inclusion of electron-hole effects are consistent with available experimental measurements. Consistencies of our findings with experimental data validate the effectiveness of electron-hole interaction for theoretical investigation of optical properties. Keywords: DFT, Quasi-particle many-body perturbation theory, Bethe-Salpeter equation, Second generation TIs, Electron-hole interaction

-2D layered. The results obtained herein hold promise for structural, elastic, and optical properties and pave the way for potential applications in electronic and optoelectronic devices.

This study examined the evidence of climate change and adaptation strategies among grain farmers in Sokoto state. The paper focused at finding out the farmers' knowledge of climate change and adaptation strategies. Rainfall and temperature data for 30 years were sourced from the Sokoto Rima Basin Development Authority's Rainfall Reading Office, Goronyo and Nigerian Metrological Services (NIMET) Oshodi, Lagos and used for this study. Purposeful sampling technique was used in the selection of 385 respondents. Farmers' perception and adaptation strategies to climate change were obtained by means of structured questionnaire administered to the sampled grain farmers. The results were summarized by means of frequencies and percentages and presented in tabular forms, trend lines and bar charts. The study revealed that farmers' perceptions of climate change issues are in line with the analysed climate records for the area; the annual rainfall totals favour the cultivation of millet; there is late onset of rain and frequent agricultural drought which affects grain production in the area. The study recommends that the research institutes should produce better adapted varieties of millet and other grains and government should subsidize the seeds to the farmers. Furthermore, there should be adequate provision for irrigation, weather forecasting and other agricultural technological infrastructure, modern knowledge on climate change adaptation and strengthening of the extension services. The study concludes that the climatic characteristics of the study area affect grain production and that adaptation strategies have significant contribution on grain production in the area.

The development of Grey Wolf Optimisation (GWO) Algorithm was motivated by the biological behaviours of swarm of wolves hunting for prey. This paper presents recent progress on Grey Wolf Optimization (GWO) algorithm, its variants and their applications, issues, and likely prospects. The review revealed that opportunities still exists for development of more robust and stable variants of GWO that will overcome the shortcomings of existing variants. This review has the potential to stimulate researchers in the area of nature-inspired algorithms to further advance the effectiveness of the GWO and its ability to solve problems. Such problems can be real-life, complicated and nonlinear optimization problems in different domain of human endeavour. Suggestions for new research directions that have the capacity to increase the performance of GWO are presented. It is expected that this paper will serve as reading material for beginners whereas experienced researchers can also use it as an article yardstick for further development of GWO algorithms.

The purpose of the study was to determine the students' error in learning trigonometry A total of 80 Senior Secondary 2 mathematics students randomly selected from two private schools in Zaria with a mean age of 17 constituted the sample size for the study. The Mathematics achievement tests (MAT) and Trigonometrical diagnostic test (TDT) were used as the instruments of this study that included two components: the use of formula and right-angled method. Diagnostic interview was also used to identify at which level students' errors occur in solving problems. The type of error is based on Newman Error Hierarchy Model that includes reading type error, comprehension, transformation, process skill, and encoding error. Data was analyzed using descriptive statistics: percentage and frequency. The study found out among others that most students make error in transformation and process skill in solving problems in trigonometry. There was no error found in reading. The number of students who made encoding error and carelessness was small. The students' error in solving trigonometrical problems was due to their weaknesses in basic arithmetical operations. The implication of the study was highlighted and recommendations were made based on findings.

The present work analyses the combined effects of variable viscosity and thermal conductivity on fluid flow and thermodynamics in a vertical channel. Equations of energy and momentum that describe the flow situation are solved using Homotopy perturbation method. The influence of various flow parameters are presented graphically and discussed. The analysis carried out revealed that fluid temperature and velocity increase with an increase in heat generation and decrease with an increasing heat absorption. Also, fluid velocity decreases with the increase of the viscosity. While both fluid temperature and velocity decrease with an increase in thermal conductivity. The comparison of the present work with Jha and Ajibade [18] shows an excellent agreement when the viscous dissipation, variable viscosity as well as the variable thermal conductivity terms are neglected.

As the world's climate changes, largely due to the spade of industrial "progress" and increase in human number, the emission of Green House gases into the atmosphere has grave implications on human health globally Within this context, 'third world' countri hit by the immediate impact of climate change, even though they contribute least to the cause of the problem -emission of Green House gases, in comparison with their counterparts in the global North. Greenhouse gases (GHGs) have been proven to be responsible for global warming with the consequent threat to climate change. This paper contends that climate change is a major threat facing human health and existence in Nigeria and attempts a critical analysis of the roles of developed and developing countries in contributing to the problem. It raises empathetic tone for the world's less privileges and future generation. The paper focuses on the impacts of climate change on Nigeria's economy, agriculture, health, security paper submits that for the effects of climate change to be effectively resolve or managed in Nigeria and indeed globally, there should be, among other things, a sustained commitment on the part of the developed economies towards assisting developing countries in tackling the problem; attitudinal change and reorientation on the part of the populace towards environmental security and green-friendly initiatives, adaptation to climate change requires public health strategi improves surveillances. The paper ends with way forward on how causes of climate change can be adapted as well as mitigated.

Bio-based polymers have become feasible alternatives to traditional petroleum-based plastics. In recent years, there has been a marked increase in interest in biodegradable materials for use in packaging, agriculture, medicine, and other areas. Polymers form the backbones of plastic materials, and are continually being employed in an expanding range of area. As a result, many researchers are investing time into modifying traditional materials to make them more user-friendly, and into designing novel polymer composites out of naturally occurring materials. A number of biological materials may be incorporated into biodegradable polymer materials, with the most common being starch and fiber extracted from various types of plants. The belief is that biodegradable polymer materials will reduce the need for synthetic polymer production (thus reducing pollution) at a low cost, thereby producing a positive effect both environmentally and economically. This paper is intended to provide a brief outline of work that is under way in the area of biodegradable polymer research and development.

The paper investigates the oil price fluctuation on exchange rates for main African net oil importing countries, namely South Africa, Morocco, Côte d’Ivoire, Kenya, Ghana and Senegal that cover for the period from 1983Q2 to 2018Q4. In order to thoroughly examine the subject matter, this study takes a specific account of the symmetric and asymmetric effects of oil price changes in modelling process by utilizing innovative linear autoregressive distributed lag (ARDL) technique and asymmetric nonlinear autoregressive distributed lag (NARDL) technique, which accommodate the short-run and long-run asymmetries via positive (increase) and negative (decrease) partial sum decompositions of oil price shocks. The result suggests that the variables are cointegrated, signifying the evidence of long and short run relationships of each country. Evidence of long and short run asymmetries is also confirmed in Côte d’Ivoire, Ghana and Senegal, suggesting that rising and declining oil price have different effect on exchange rate, while symmetric effect is observed in South Africa and Morocco. Rising oil price has positive effect on exchange rate in South Africa and Senegal leading to depreciation of exchange rate, while falling oil price leads to exchange rate appreciation of South Africa rand, Ghanaian cedi and Senegal francs but exchange rate depreciation of Moroccan dirham and Cote d’Ivoire francs. The result further suggests that negative decrease in oil price has a larger impact on exchange rate than the positive increase that varies in sign and size across countries. This suggests that oil price changes play a significance role that influence the behaviour of exchange rate and hence leading to contribute to the development of national economic progress.

This work concerns a theoretical investigation on the effects of suction/injection, magnetic field, permeability of porous materials and viscous dissipation on an electrically conducting incompressible fluid passes through a vertical porous channel filled with porous materials. One of the plates moves in the flow direction while the other is stationary. The governing coupled flow equations have been solved analytically using Homotopy Perturbation Method (HPM). The influences of the flow parameters on velocity and temperature were plotted on graphs while numerical values for rate of heat transfer and shear stress on the heated and cold plates were presented in tables. Excellent agreements were found when compared with the previous works. It is noteworthy to mention that the hydrodynamic and thermodynamic distributions of the fluid increase with increase in viscous dissipation [Formula: see text]. It is also found that the shear stress decreases with increase in the magnetic field [Formula: see text] while a reverse case was observed for growing the permeability of the porous materials [Formula: see text]. It is further found that the velocity and temperature distributions decrease with increase in suction [Formula: see text].

Urban and peri-urban agriculture in dry semi-arid northern Nigeria relies on untreated wastewater for all-year irrigation and the production of vegetables for urban markets. Human and animal exposure to potentially toxic metals is attributed to the consumption of vegetables raised in metal-polluted soils. The objective of this study was to determine the bioavailability and soil–plant transfer of Cd, Pb and Zn to amaranthus (Amaranthus caudatus) and lettuce (Latuca sativa) raised in the garden fields and to assess their safety for human consumption. Ten farmers’ fields were selected per location for analysis of Cd, Pb and Zn in soils and vegetables. Whereas total concentrations of Cd and Zn were greater than the safe or permissible limits for agricultural soils, the Pb concentration was less than its maximum allowable concentration. However, the concentration of Pb and Cd in edible portions of amaranthus exceeded the safe limit for human consumption by 7–13 times, while lettuce exceeded the limit by 11–17 times. Cadmium was more rapidly transferred from soil through root to shoot than Zn > Pb. The plant tissue concentrations of the metals were not significantly correlated with the Diethylene triamine pentaacetic acid (DTPA) and dilute CaCl2-extractable concentrations of the metals in the soils. Furthermore, permissible limit of Pb established as standards for agricultural lands may not be suitable to ensure produce safety in Urban and peri-urban agriculture (UPA) in the city of Kano.

There has been a rise in the demand for blockchain-based smart contract development platforms and language implementations. On the other hand, smart contracts and blockchain applications are generated using non-standard software life cycles, which means that, for example, distributed applications are rarely updated, or bugs are fully addressed by releasing a newer version, leading to security flaws and challenges for users to adopt the technology. Smart contracts have gained significant attention due to their potential to automate and secure various transactions in diverse domains. However, the increasing adoption of smart contracts has also raised concerns about security vulnerabilities and potential risks. In this paper, an overview of smart contracts was discussed in detail. It further distinguished and compared smart contracts security with conventional security regarding security, privacy, communication channel, etc. Different platforms for smart contracts, such as Bitcoin, Ethereum, Counterparty, Stellar, Monax, and Lisk, are also discussed in this paper. Some proposed techniques are used in different areas for handling security threats in smart contracts. In addition, a taxonomy of the smart contracts security application was proposed, which attempts to solve some of the flaws and inadequacies in smart contracts. The study also provides a comprehensive smart contracts security scenario with different techniques. Lastly, the possible attacks posed by threats and vulnerabilities of the smart contracts are provided. The security threats and vulnerabilities addressed in this study are unique to smart contracts.

Antimony sulfide (Sb2S3) micro thin-film have been received great interest as an absorbing layer for solar cell technology. In this study, to explore its further potential, electronic and optical properties of Sb2S3 simulated nano-thin film are investigated by the first-principles approach. To do so, the highly accurate full-potential linearized augmented plane wave (FP-LAPW) method framed within density functional theory (DFT) as implemented in the WIEN2k package is employed. The films are simulated in the [0 0 1] direction using the supercell method with a vacuum along z-direction so that slab and periodic images can be treated independently. From our calculations, indirect band gap energy values of Sb2S3 for various slabs are found to be 0.568, 0.596 and 0.609 eV for 1, 2 and 4 slabs respectively. Moreover, optical properties comprising of real and imaginary parts of the complex dielectric function, absorption coefficient, refractive index are also investigated to understand the optical behavior of the obtained simulated Sb2S3 thin films. From the analysis of their optical properties, it is clearly seen that Sb2S3 thin films have good values for optical absorption parameters in the visible and ultraviolet wavelength range, showing the aptness of antimony sulphide thins films for versatile optoelectronic applications as a base material. Keywords: DFT, LAPW, Sb2S3, Thin-film, Solar cell, Optical properties

In this study, the optical refractive constants of the (5, 5) SWBNNT and (5, 5) SWCNT systems were calculated in both parallel and perpendicular directions of the tube axis by using Quantum ESPRESSO and YAMBO code. It also extended the optical behaviors of (5, 5) SWCNT and (5, 5) SWBNNT to both perpendicular and parallel directions instead of the parallel directions reported in the literature. It also looked at the effects of the diameter of the nanotube on the optical properties instead of chiral angles. From our results, the best optical reflection was found for (5, 5) SWBNNT, while the best optical refraction was found with (5, 5) SWCNT. It was observed that the SWCNT demonstrates refraction in both parallel and perpendicular directions, while (5, 5) SWBNNT shows perfect absorption in perpendicular direction. These new features that appeared for both nanotubes in perpendicular directions were due to new optical band gaps, which appear in the perpendicular directions to both nanotubes’ axis. The electron energy loss (EEL) spectrum of SWBNNT revealed the prominent π- and π + δ- Plasmon peaks, which demonstrates themselves in the reflectivity spectrum. Furthermore, little effect of diameter was observed for the perpendicular direction to both nanotubes’ axis; as such, the combined properties of (5, 5) SWBNNT and (5, 5) SWCNT materials/systems for transmitting light offer great potential for applications in mobile phone touch screens and mobile network antennas. In addition, the studies of optical properties in the perpendicular axis will help bring ultra-small nanotubes such as SWCNT and SWBNNT to the applications of next-generation nanotechnology.

This study investigates the effect of exchange-correlation on the electronic properties of hybridized hetero-structured nanomaterials, called single-walled carbon boron nitride nanotubes (SWCBNNT). A first principles (ab initio) method implemented in Quantum ESPRESSO codes, together with different parametrizations (local density approximation (LDA) formulated by Perdew Zunga (PZ) and the generalized gradient approximation (GGA) proposed by Perdew–Burke–Ernzerhof (PBE) and Perdew–Wang 91 (PW91)), were used in this study. It has been observed that the disappearance of interface states in the band gap was due to the discontinuity of the π–π bonds in some segments of SWCNT, which resulted in the asymmetric distribution in the two segments. This work has successfully created a band gap in SWCBNNT, where the PBE exchange-correlation functional provides a well-agreed band gap value of 1.8713 eV. Effects of orbitals on electronic properties have also been studied elaborately. It has been identified that the Py orbital gives the largest contribution to the electrical properties of our new hybrid SWCBNNT nanostructures. This study may open a new avenue for tailoring bandgap in the hybrid heterostructured nanomaterials towards practical applications with next-generation optoelectronic devices, especially in LED nanoscience and nanotechnology.

Ransomware attacks constitute major security threats to personal and corporate data and information. A successful ransomware attack results in significant security and privacy violations with attendant financial losses and reputational damages to owners of computer-based resources. This makes it imperative for accurate, timely and reliable detection of ransomware. Several techniques have been proposed for ransomware detection and each technique has its strengths and limitations. The aim of this paper is to discuss the current trends and future directions in automated ransomware detection. The paper provides a background discussion on ransomware as well as historical background and chronology of ransomware attacks. It also provides a detailed and critical review of recent approaches to ransomware detection, prevention, mitigation and recovery. A major strength of the paper is the presentation of the chronology of ransomware attacks from its inception in 1989 to the latest attacks occurring in 2021. Another strength of the study is that a large proportion of the studies reviewed were published between 2015 and 2022. This provides readers with an up-to-date knowledge of the state-of-the-art in ransomware detection. It also provides insights into advances in strategies for preventing, mitigating and recovering from ransomware attacks. Overall, this paper presents researchers with open issues and possible research problems in ransomware detection, prevention, mitigation and recovery.

Inauguration ceremony of a new president is likely a common ritual the world over. It is an observance that constitutes the formal investiture for the president. Inaugural speech is central to the rites of inauguration and it is usually anticipated for the soothing promises it makes and the reassurances it contains. This study investigates pragmatic presuppositions made and politeness strategies employed by President Donald Trump in the speech delivered at his inauguration ceremony. The text of the speech is downloaded from the net to ensure accuracy and the ninety-nine (99) sentences in it numbered serially for ease of reference and close analysis. The study reveals that Trump presupposes among others the uniqueness of the event, the socio-economic crisis bedevilling America and the imperative and urgency of the need to salvage her. Regarding politeness, the paper unravels both the face saving and face threatening acts performed by the speaker and the various strategies deployed. It concludes that although Trump strives hard to mitigate the threats to the face of the past American leaders among others, the poignancies of the threat still remain painfully memorable for their enormity and emphasis.

The electron transfer reaction of Tris (1,10-phenanthroline)cobalt(III) complex by thiosulphate ion has been studied in an aqueous acidic medium. Stoichiometric determination shows that for one mole of the oxidant that was reduced, one mole of the reductant was consumed; the reaction conforms to an overall equation: 2[Co(phen)3]3+ + 2S2O32− → 2[Co(phen)3]2+ + S4O62− Kinetics study carried out under pseudo-first order condition shows that the reaction proceeded via a one-way acid-dependent pathway and was third order overall; zero order with respect to the oxidant concentration, second order with respect to the reductant concentration and first order with respect to the hydrogen ion concentration. The empirical rate law conforms to the equation: −  {Co(phen)3}3+] = a [H+] [S2O32−]2 ‘a’ = 128.26 dm6 mol−2 s−1: at [H+] = 2.0 × 10−2 mol dm−3, µ = 0.4 mol dm−3 (NaCl), T = 28 ± 1ËšC and λmax = 495 nm.The rate of reaction increased at the increase in ionic strength and at the decrease in medium dielectric constant. Added cations and anions catalyzed and inhibited the reaction rates respectively. The Michaelis-Menten plot of 1/k1 versus 1/[S2O32−]2 started from the origin. Hence based on spectroscopic investigation, thermodynamic information from temperature dependence studies and kinetic evidence from Michaelis–Menten plots and the interactions with added ions, an outer-sphere mechanism has been rationalized for this reaction. The mechanistic scheme of the reaction was proposed via the stated mechanistic route.  Â