bluuebunny/crossref_metadata_2025 huggingface dataset:
Diffraction of vortex Gaussian beams from a two-dimensional Raman-induced grating
Authors: Arkhipkin V G , Myslivets S A
Published: April 2021

In this paper, we study diffraction of a vortex Gaussian probe beam on a two-dimensional (2D) Raman-induced diffraction grating. Both near- and far-field diffraction of a vortex beam is considered. In the near field, quasi-Talbot images occur at specific distances from the grating, which corresponds to the classical Talbot length. Diffraction patterns in the Talbot planes are a periodic 2D array of ring-like vortex beamlets with topological charges (TCs) equal to the illuminating probe beam’s charge. The lateral (off-axis) beamlets consist of several overlapping vortices with the TCs l = 1 and l =−1, and their centers (singular points) are offset relative to each other. It is shown that in the near field the TC is conserved, and the total diffraction field represents a single (global) vortex with an effective TC equal to the charge of the vortex probe beam. In the far field, diffraction patterns are also a 2D array of ring-like local vortices with a period depending on the z coordinate. Their TCs are equal to the charge of the probe field. It is shown that in a far field, the diffracted field’s total TC is also equal to that of the probe field. We demonstrate that by choosing the pump field parameters, one can effectively control the intensity of diffraction orders.
Design of Dynamic Evaluation Algorithm for Classroom Mathematics Teaching
Authors: Cai Wenhuan
Published: April 2021

With the reform and development of education, there is a clear gap between our country’s current evaluation theories, methods and systems and the requirements of quality education, which has become a bottleneck restricting the overall implementation of quality education. Therefore, explore and try to change the evaluation function, evaluation method, evaluation technology and other content, establishing a developmental mathematics teaching evaluation system that embodies the theory of quality education is an objective requirement for the overall implementation of quality education. The purpose of this article is to research and design the dynamic evaluation algorithm of classroom mathematics teaching. This article takes the city’s key teaching reform subject “Research and Practice on the Dynamic Evaluation Method of Classroom Mathematics Teaching” as the research background to develop a classroom math teaching quality evaluation system. On the basis of inheriting the original, feasible and effective classroom mathematics teaching evaluation methods and means, this paper establishes a set of classroom mathematics teaching evaluation system structure, and uses the network-based computer evaluation system as a tool to complete the collection and arrangement of evaluation data And analysis process, provide a random evaluation platform for each evaluator, record all evaluation activities and evaluation results of the evaluator, and provide it to the evaluators for evaluation information query. This article gives a comprehensive evaluation method for teachers’ mathematics teaching effect, which can be both quantitative and qualitative. It can give a comprehensive evaluation of the combination of quantity and sex to each link of teacher’s mathematics teaching according to the change of evaluation information. Experimental research shows that teachers with a Ph.D. degree in language behavior are about 12% higher than those with a master’s degree, and the proportion of classroom silence and technology usage is lower than that of teachers with a master’s degree.
Keywords of Search Engine Optimization based on Corpus
Authors: Li Runtao
Published: April 2021

With the development of network, keywords have become an important way of retrieval, which is the window for academic papers to enter circulation and citation. Therefore, the selection of keywords is very important to improve the retrieval rate. Based on this, this paper carries out a corpus based search engine optimization keyword research. Based on one million English corpora, this paper analyzes and studies 3933 key words from the definition and function of keywords, the characteristics of keywords, selection methods, arrangement order, composition, quantity and writing format. It also analyzes the algorithm and ranking principle of search engine, discusses the optimization of website structure, keywords and single page, the punishment of search engine and the rescue method after being punished by search engine. According to the statistical research on the frequency of key words, the number of keywords is mainly 1-2 words, accounting for 90% of the total number. It can be seen that the search engine optimization technology used in the research of keyword optimization in the website can improve the website ranking and realize the value of the website.
Computer Network Security under the Background of Big Data
Authors: Chen Fei
Published: April 2021

With the advent of the era of big data, data has exploded. This paper mainly studies the analysis of computer network security under the background of big data. In order to make these data intuitively reflect the network security situation, this paper uses the method of weight allocation to normalize the five groups of data, and allocates a larger weight to the security problems with high network security threat and a small weight to the security problems with low network security threat. In this paper, 3603 sample data are randomly selected as evaluation data according to the proportion of the type of data set unchanged. After setting the parameters, you can train and test. According to the risk level, take corresponding control measures to control the system risk at an acceptable level. The data shows that a certain number of attacks are carried out on the protected network in the 5th, 12th, 20th, 28th, 36th, 44th and 52nd minutes, and the scale of each attack is twice that of the last attack. The results show that the construction and deduction method of network security event scenarios can provide effective support for the research of network security incident coping strategies.
Data Transmission Security in Computer Network Communication
Authors: Chen Fei
Published: April 2021

In recent years, computer network communication technology has made considerable progress and development, and its scale has now covered all aspects of society and people’s lives. However, while computer network technology promotes social development and improves the convenience of people’s lives, there are still many security problems, especially the difficulty of ensuring the security of user data, which has become a prominent problem in the further development and improvement of communication technology. This article takes the network communication security technology as an entry point, and analyzes its technical types with the aid of data encryption technology, and then analyzes and studies its security in computer network communication data transmission according to the specific points proposed. Through the substantial technical analysis of the computer network security system, the possibility of the system being attacked can be reduced to a certain extent, and the security of network data can be improved. Through the analysis of the integrity of the network system, the overall framework of a distributed network security early warning system based on the network is established, and various structures of the system are analyzed. The network load analysis module is responsible for using key performance index data, such as user traffic, number of users and wireless utilization, and analyzes and classifies the network cell load by combining the partial least square method and BP neural network, so that the key cell performance analysis module is mainly Analyze key performance index data of key communities, obtain early warning thresholds through clustering algorithms, and implement a dynamic early warning system to provide guidance for network planning and mining in key small areas. The database module is responsible for storing all performance data and performance analysis results; the performance query module is responsible for querying and analyzing performance data and static warnings, and presents them to users in the form of text and graphics. Experimental research results show that in this information age, the development of computer networks plays a very important role in the development of our country. Computer network operators make full use of cluster analysis, data mining, encryption algorithms, and early warning systems to conduct research to fully improve the security performance of data in network communications.
Innovative Application of Artificial Intelligence Technology in College Physical Education
Authors: Wen Jiao
Published: April 2021

Against the background of the new era, the birth of artificial intelligence technology opened a new chapter in human development. Artificial intelligence technology has been developed in many places. The report discusses the application and innovation of artificial intelligence technology in college sports. The first thing people think of artificial intelligence is robots. In fact, it can be said that artificial intelligence can replace human labor. Artificial intelligence is a product of modern technology and cannot be understood unilaterally. For example, the various means of transportation used in people’s daily travel is an artificial intelligence that can replace people’s walking. Another example is that elevators can replace people on stairs. It is also a type of artificial intelligence, which is not an advanced technology. Product, it is also seen everywhere in people’s daily life. Artificial intelligence is a synthesis of scientific and intelligent technology created by human beings. It is a scientific technology including computer science, cognition, logic, etc., formed through mutual intersection and integration. In recent years, artificial intelligence has achieved considerable development, but there are still a series of unsolved problems, and the development of artificial intelligence is still very long. This article studies what artificial intelligence has facilitated and changed the physical education in colleges and universities, and what changes have taken place in the teaching mode are all worthy of our thinking. As a result, artificial intelligence technology is convenient for teachers and students in teaching. Let’s take a look at how to innovate.
Variational Quantum Algorithm and Its Application on Non-Linear Equations
Authors: Yang Yihang , Shan Zheng , Zhao Bo , Xu Le
Published: April 2021

Quantum algorithms of factoring problem have been paid more and more attention since Shor’s algorithm was proposed. Combining the current quantum computer hardware level and integer factorization quantum algorithms, this paper proposes a “classical + quantum” hybrid solution. This scheme first adopts classical methods and corresponding rules in the preprocessing step to simplify the nonlinear equations, which is used to reduce the number of qubits needed for the cost Hamiltonian. Then the variational quantum algorithm is used to find the approximate ground state of the cost Hamiltonian, which encodes the solution of the nonlinear equations. The program was verified on the IBM QX4 quantum machine, and the results showed that this hybrid solution can effectively reduce the quantum resources required to solve the nonlinear equations.
Hierarchical Attention Maps for Super Resolution
Authors: Zhang Zhiqin , Zhang Bo
Published: April 2021

Recent state-of-the-art super-resolution methods have achieved impressive performance on ideal datasets. However, these methods always fail in balance between spatial details and high-level perceptual information. Most of them adopt downsampling step to construct Low-Resolution (LR) and High-Resolution (HR) training which may lose local spatial details. To address this issue, we focus on designing a hierarchical attention maps mechanism for recovering both local spatial details and global perceptual information. By using our novel Hierarchical attention module, we can acquire better High-Resolution (HR) predicted images. Finally, we propose a hierarchical multiple scale feature concatenation module aiming at better perception. Extensive experiments on real-world images demonstrate that our method achieved better visual quality both for perception and quantitative estimation.
RETRACTED: A Feasibility Study on Improving the Quality of Sports Competitions Based on Big Data Analysis
Authors: Li Guangjian
Published: April 2021

With the development of China’s sports power development strategy, the quality of sports competitions also needs to be further improved. Only in this way can we better play its role in promoting sports and sports. The application of big data technology is an important way to improve the quality of sports competitions. Big data technology can not only comprehensively mine and collect sports competition data, but also perform objective, comprehensive and efficient analysis and processing of massive technologies. This will not only provide better protection for athletes, but also provide spectators with a better watching experience, thus laying a good foundation for comprehensively improving the quality of sports competitions.
Environmental and political implications of underestimated cropland burning in Ukraine
Authors: Hall Joanne V , Zibtsev Sergiy V , Giglio Louis , Skakun Sergii , Myroniuk Viktor , Zhuravel Oleksandr , Goldammer Johann Georg , Kussul Nataliia
Published: April 2021

Open burning is illegal in Ukraine, yet Ukraine has, on average, 300 times more fire activity per year (2001–2019) than most European countries. In 2016 and 2017, 47% of Ukraine was identified as cultivated area, with a total of 70% of land area dedicated to agricultural use. Over 57% of all active fires in Ukraine detected using space-borne Visible Infrared Imaging Radiometer Suite (VIIRS) during 2016 and 2017 were associated with pre-planting field clearing and post-harvest crop residue removal, meaning that the majority of these fires are preventable. Due to the small size and transient nature of cropland burns, satellite-based burned area (BA) estimates are often underestimated. Moreover, traditional spectral-based BA algorithms are not suitable for distinguishing burned from plowed fields, especially in the black soil regions of Ukraine. Therefore, we developed a method to estimate agricultural BA by calibrating VIIRS active fire data with exhaustively mapped cropland reference areas (42 958 fields). Our study found that cropland BA was significantly underestimated (by 30%–63%) in the widely used Moderate Resolution Imaging Spectroradiometer-based MCD64A1 BA product, and by 95%–99.9% in Ukraine’s National Greenhouse Gas Inventory. Although crop residue burns are smaller and emit far less emissions than larger wildfires, reliable monitoring of crop residue burning has a number of important benefits, including (a) improving regional air quality models and the subsequent understanding of human health impacts due to the proximity of crop residue burns to urban locations, (b) ensuring an accurate representation of predominantly smaller fires in regional emission inventories, and (c) increasing awareness of often illegal managed open burning to provide improved decision-making support for policy and resource managers.
Characterising stochastic motion in heterogeneous media driven by coloured non-Gaussian noise
Authors: Mutothya Nicholas Mwilu , Xu Yong , Li Yongge , Metzler Ralf
Published: April 2021

We study the stochastic motion of a test particle in a heterogeneous medium in terms of a position dependent diffusion coefficient mimicking measured deterministic diffusivity gradients in biological cells or the inherent heterogeneity of geophysical systems. Compared to previous studies we here investigate the effect of the interplay of anomalous diffusion effected by position dependent diffusion coefficients and coloured non-Gaussian noise. The latter is chosen to be distributed according to Tsallis’ q-distribution, representing a popular example for a non-extensive statistic. We obtain the ensemble and time averaged mean squared displacements for this generalised process and establish its non-ergodic properties as well as analyse the non-Gaussian nature of the associated displacement distribution. We consider both non-stratified and stratified environments.
Compressive Strength of a Prescribed Control Mix for High Performance Self-compacting Concrete
Authors: Mark O G , Ede A N , Arum C , Bamigboye G O , Oyebisi S O , Jolayemi K J
Published: April 2021

Another way of improving concrete production involves incorporating the unique features of high performance concrete with the special properties of self-compacting concrete, resulting in another type of concrete called high performance self-compacting concrete (HPSCC). Many researchers have developed diverse designed control mix for HPSCC which were obtained through several and rigorous designed trial mixes. Yet, little work has been done on prescribed control mix for HPSCC. The purpose of this paper is to establish a prescribed control mix ratio for HPSCC and to test by conducting compressive strength test. Review of the various designed control mix ratios is done in this paper. A logical prescribed control mix ratio of 1:1.02:0.95 has been established for an HPSCC with 0.36 w/c proportion, 0.02 superplasticizer/cement proportion. The compressive strength gave 36.10 MPa at 7 days curing age, 41.76 MPa at 14 days curing age and 57.29 MPa at 28 days curing age. This strength result satisfied the strength criteriaa of HPSCC, according to EFNARC It is therefore recommended that a prescribed control mix of 1:1.02:0.95 be used if the minimum crushing strength value expected at 28 days is 40 N/mm2 for an HPSCC.
Numerical Modelling of the Effect of Cooling Conditions and Mould Size during Solidification of Al-4.5%Cu Alloy in Static Casting Process
Authors: Egole C.P. , Mgbemere H.E. , Sobamowo G.M. , Lawal G.I.
Published: April 2021

Mathematical developments and computer simulation have greatly aided the modern day study of solidification phenomena. This work presents a numerical modelling of the effect of cooling conditions and mould size during solidification of Al-Cu eutectic binary alloy in static casting process. The numerical method adopted for the current work is the finite volume method and the mathematical problem was formulated according to the classic continuum energy conservation equation for the transient solidification problems. The latent heat evolution was accounted for using the modified source-based method. The boundary conditions included all the modes of heat transfer between the solidifying system and its surrounding. Two cases were simulated to study the effect of cooling conditions and mould size on the solidification system. In case I, a Dirichlet boundary condition with a known temperature (373 K) value was imposed on the bottom of the mould surface. An adiabatic condition was imposed on the bottom of the mould in case II. It was observed that the different boundary conditions and mould sizes have significant influence on the rate and pattern of solidification. Cooling curve results and temperature contours from these models showed reasonable deviations due to various cooling conditions and mould sizes. Larger thermal and solid fraction layers were predicted for the case II with slower cooling rate. It was also observed that temperature distribution along the horizontal distance within the casting increases monotonically as mould size was increased.
An Insight into Deployments of Green Base Stations (GBSs) for an Environmentally Sustainable World
Authors: Ehiagwina F. O. , Kehinde O. O. , Adewale A. A. , Seluwa O. E. , Anifowose J. J.
Published: April 2021

Data traffic and the number of mobile subscribers have increased significantly prompting cellular network operators to install additional mobile cellular base stations (BSs) to meet the increasing demand. This proliferation of BSs has resulted in consequential increase in energy consumption and Green House Gases (GHGs) emission. Several techniques have been deployed to reduce the energy consumption of the base station in what is called a green base station. This paper presents an insight into these approaches and highlights key challenges and potential research directions. It also highlights what environmental sustainability activist, regulators and government can do to incentivize green BSs concept in Nigeria.
Non-Destructive Testing on Concrete Subjected to Chemical Condition
Authors: Olowofoyeku A , Ofuyatan O , Oluwafemi J
Published: April 2021

Regular in-situ inspection of structures is required for accessing the condition of concrete. In concrete, several unpredicted and uncontrollable factors affect the expected performance and life cycle of the structures. Non-destructive testing can be applied to both new and old structure to monitor infrastructures. This test is better known to assess and evaluate the condition of concrete. In this investigation, the non-destructive testing and destructive testing were used to estimate the strength of concrete cubes of M25 subjected to 28days of curing with acid at varying PH values (1.5, 2.5 and 3.5) and water. The test was used to determine the strength of the cubes. From the result he concluded that cubes cured with water had better strength throughout the test and gradual deterioration was observed in the cube specimen subjected to acid.
Static Analysis of the Last Stage Low Pressure Steam Turbine Blade to Improve Blade twist Angle
Authors: Omosanya Abolaji Joseph , Akinlabi Esther Titilayo , Okeniyi Joshua Olusegun
Published: April 2021

Demand for electricity is growing continuously and the production is still based on limited sources of energy, mainly the turbomachinery, which include basically the steam and gas turbines. Turbomachinery is responsible for about 80% of the electricity generated worldwide. A large variety of turbine blade geometries are in use today, however, there is no specific attempt made to compare them based on performance.

This paper presents a study on the effect of the twist angle of the steam turbine blade on different choice blade materials. For the study, the aerodynamic and static loading of the 19th stage low pressure turbine blade of Egbin thermal power station was evaluated. Static analysis based on computational fluid dynamics (CFD) was used to simulate the conditions of the turbine blade during normal operating conditions. Alternative materials (such as stainless steel 316, Titanium alloy) and varying twist angles were observed to be showing different forms of results in the simulation on ANSYS. From these, an optimized twist angle was generated using Response Surface Optimization on ANSYS RSO, and the consequent results were discussed.
Control Design of an Inverted Pendulum on a Moving Base Using State Feedback
Authors: Oguntosin Victoria , Oruma Samson Ogheneovo , Akindele Ayoola , Abdulkareem Ademola
Published: April 2021

A fascinating and essential control problem for researchers is the inverted pendulum. It remains a generally accepted standard used in control and robotics for validation of emerging control technologies. A mathematical model of the inverted pendulum on a moving base system was derived, an expression of the linearised state space representation of the system was also presented, a controller to achieve specific criterion of the steady state error, rise and settling time, and was obtained, an implementation of this control on MATLAB was carried out together with the simulated animation of the system using Simulink and Simscape.
Effect of the Parametric Processes in Stir-Casting Technique for Aluminium Based Composite Development: A review
Authors: Fayomi J. , Popoola A.P.I. , Fayomi O.S.I.
Published: April 2021

The extensive usage of aluminium based composites are seen in automobile industry, aviation, marine, and general structural engineering applications due to their distinctive features that cannot be observed in individual constituent materials. Aluminium form the continuous matrix phase and other discontinuous reinforcing materials are incorporated into the matrix to achieve a composite. There are numerous ways in which composites are developed and stir casting process has been a great technique. In stir casting process, the extent of the process parameters determines the outcome of the material properties and the microstructural evolution. Hence, this review work focus on the effect of different process parameters such as the stirrer speed, blade, stirring time, temperature, and the reinforcement weight fractions on the mechanical, corrosion, tribology, and microstructure of the developed aluminium metal matrix composites (AMMCs). The different parametric processes improve the properties of materials in diverse ways as discussed by several authors.
Study on adsorption mechanism of Metronadiazole activities on Aluminium in 0.5M H2SO4
Authors: Williams A.B. , Sanni O. , Fayomi O.S.I. , Popoola A.P.I.
Published: April 2021

The inhibition of pure aluminium alloy at a varying concentration of Metronadiazole (MNZ) in 0.5M H2SO4 solution has been studied using electrochemical techniques. The obtained results unveil a decrease in the corrosion rate and high inhibition efficiency values with an increase in the Metronadiazole concentration in the corrosive solution. The samples inhibited exhibits higher polarization resistance value and reduced current densities compared to the uninhibited sample. A mixed inhibition mechanism was proposed for the inhibitive effect of MNZ as shown by the potentiodynamic polarization method. Maximum inhibitory efficiency of 80.53% was recorded for the 12.5 mL MNZ inhibited sample. The obtained results show that MNZ inhibited the pure aluminium corrosion in the sulphuric acid solution by adsorption onto the metal surface fitting the Freundlich adsorption isotherm with a correlation regression coefficient of 0.949.
Comparative Effect of Some Carbon Rich Materials on the Hardness Property of Carburized Low Alloy Carbon Steel
Authors: Joshua T.O. , Fayomi O. S. I. , Seriki Ege O. , Udoye N.E
Published: April 2021

This work focuses on the effects of carburization process, on the hardness property of carburized low alloy carbon steel, at temperature of 890°C with varied soaking time of 1 hour, 2 hours and 3 hours, after which the samples were later quenched in air. The carbon rich materials used in this work include: coal dust, snail shell particulate, palm kernel shell and cow bone while 20% limestone was used as the energizer. Thirteen specimens were machined to specifications from 10mm diameter mild steel and each set of the specimens were randomly assigned to hardness test. Twelve pack boxes measuring 150mm x 75mm x 75mm was fabricated from gauge 18 mild steel. Carbon rich materials and specimens were carefully placed into the pack boxes, a specimen each was packed into the four boxes meant for coal dust, snail shell, carbonized palm kernel shell and cow bone respectively. Each box was labeled accordingly, and were loaded into heat treatment furnace and carburized at a soaking temperature of 890°C. At appropriate times, each sets of boxes were removed, open and air cool. Hardness testing of the various specimen were conducted using Vickers hardness test machine. Both coal dust, snail shell, palm kernel shell and cow bone were observed to have increase the hardness of the samples when compared with the as-received sample. As holding time of specimen increase in each carbonaceous materials, carbon diffusion and penetration increases which resulted to increase hardness values recorded in samples with 3 hours holding time.
Characteristics and utilization of Jarosite and fly ash wastes in the construction industry: an overview
Authors: Mubiayi Mukuna Patrick , Fayomi Ojo Sunday Isaac
Published: April 2021

Worldwide, there is a daily production of wastes include fly ash and jarosite which can have a detrimental effect on the environment. Many researchers have utilized fly ash and jarosite to fabricate products include bricks, concrete which are used in the construction industry. This review paper presents the characteristics of jarosite and fly ash. Furthermore, it summarizes selected studies carried out on the successful reuse of jarosite and fly ash as a component in some construction materials. It has been reported that using certain ratios in bricks and concretes made with jarosite and fly ash as constituents can display satisfactory mechanical properties such as compressive strength. Due to the high generation of wastes around the world, more studies are needed to investigate the environmental friendliness and cost-effectiveness of products made with jarosite and fly ash as a component.
Development and modelling of oil-palm-mesocarp fibre polyester resin composite for helical gears
Authors: Oghenekowho P. A. , Emagbetere E. , Aworinde A. K. , Ishola F. A. , Dirisu J. O. , Leramo R. O.
Published: April 2021

As a result of the ever-increasing need of materials with unique properties that are ecofriendly, the possibility of using Oil-Palm-Mesocarp Fibre (OPMF)as reinforcement for polyester resin was investigated for use as material for helical gears. The OPMF collected was treated with deionized water and NaOH, and then grounded to a particle size of 354 microns. The composite was then produced by adding different quantities of the OPMF (weight % of 40—10 in steps of 10%) to unsaturated polyester resin to obtain comp. 1--comp. 4. Test specimens for the various mechanical tests were prepared for the different compositions and the tests were carried out following standard procedures. SOLIDWORKS was used to simulate the actual behavior of the helical gears. Results obtained showed that the biocomposite material for all composition can be used for designing helical gears for paper shredding machine and comp. 3 had the best properties in terms of displacement.
Effects of Alloying on Aluminium-Silicon Alloys – A Review
Authors: Joseph O.O. , Olubambi P.A. , Joseph Olakunle O. , Edun B.M. , Okeniyi J.O. , Abioye O.P.
Published: April 2021

Some of the factors in which the mechanical, physical and chemical properties of aluminium alloys hinge on are composition and microstructure. The inclusion of specific alloying elements to aluminium in its pure form has been proven to considerably improve its properties and usefulness. Hence, aluminium is substituted with alloys which consist of one or more alloying elements or impurities for applications where it is demanded. Aluminium, as well as its alloys, offers an outstanding combination of properties making it stand out amongst the most adaptable, cost-effective, and appealing metallic materials for a wide scope of employments —from delicate materials like wrapping foil to the most severe engineering applications. Besides steels, aluminium based alloys are most favoured for applications as structural materials.
Optimization of Singly Reinforced Beam Design Using Simulated Annealing
Authors: Olawale S O A , Akintunde O P , Afolabi M O , Agbede O A , Ozuor O , Fayomi O S I
Published: April 2021

This paper investigated the optimization of a singly reinforced concrete beam using the Simulated Annealing. The code provisions usually lead to the overestimation of reinforcement and thus an expensive cost of construction. The optimized design reduces the cost significantly. There are many methods of structural optimization but Simulated Annealing has been found to very efficient for constrained optimization of reinforced concrete beam design. The variables considered are the width, depth, compression steel, tension steel, and cost while the constraints are steel ratios, ultimate moment of resistance, maximum and minimum areas of reinforcements Materials costs are considered as the objective function. It is demonstrated that using the concrete compressive strength of 25MPa, Simulated Annealing can be used to optimize the design of concrete beams effectively. The results also indicate that the complications connected to the actual and genuine evaluation of costs of structures and the connectivity with the compulsory restraints can be adequately resolved using this method.
Analysis of Flow Characteristics around an Inclined NACA 0012 Airfoil Using Various Turbulence Models
Authors: Olayemi O. A. , Ogunwoye O. V. , Olabemiwo J. T. , Jinadu A. , Odetunde C.
Published: April 2021

The current paper presents a computational fluid dynamic analyses of the flow characteristics over an inclined NACA 0012 airfoil using various turbulence models at Mach number of 0.13. The primitive continuity and momentum equations were solved using Ansys-Fluent in turn along with Spalart-Allmaras, Realizable
k – ε
, and
k – M
shear stress transport. The response of pressure and velocity contours, lift coefficient (
Cl

) and drag coefficient (
Cd

) to inclination angle variation from – 14° to 20° are reported. Also, the values of
Cl

and
Cd

obtained from the current work were juxtaposed with the equivalent values of experimental data gotten from earlier work done by Abbott and Von Doenhoff and the comparison showed good agreement. Furthermore, the results revealed that stalling occurred between 14° and 16°.
Biosurfactants as facilitators in Biodegradation of Low-Density Polyethylene (LDPE)
Authors: Nnaji C. F. , Ogu E. C. , Akpor O. B.
Published: April 2021

Low density polythene (LDPE) is amongst the highest produced synthetic plastic and also largely plagued with ineffective disposal management. Strategies to remedy its ineffective disposal have been underway and at the forefront is biodegradation due its positive environmental impact. This study reports on the preliminary investigation into surface chemistry using biosurfactants as facilitators for the biodegradation process of LDPE. Synthesized biosurfactants from isolated soil microbes, Bacillus subtilis and Pseudomonas aeruginosa were used in the biodegradation study along with pure cultures of the organisms themselves. 0.84mg/ml was the highest amount of biosurfactant synthesized under static conditions at 25°C. Supplementing with biosurfactants increased the biodegradation efficiency by at least 1.2 % compared to using the microbes alone during a 30 d incubation period. Percentage weight loss of LDPE bags was used as a measure of biodegradation in this study and 3.3% weight loss was the highest observed for a single organism when augmented with biosurfactants compared to 1.9% when used alone.
Correlations for the prediction of higher heating values of liquid fuels from their densities, viscosities, and flash points values
Authors: Ayeni A. O. , Agboola O. , Daramola M. O. , Folayan J. A. , Babatunde D. E. , Dick D. T. , Adeeyo O.A.
Published: April 2021

In this study, correlations of the higher heating values (HHV) of three groups of liquid fuels, vegetable oils, alkanes, and alcohols were developed through experimentation and prediction with the aid of the statistical software package MINITAB 16 (PA, USA). The HHVs (in kJ/kg), of the samples were obtained as a function of the density, viscosity, and flash points physical tests. Reliability of models were evaluated through statistical validation and cross-validation standard error of estimate (S), coefficient of determination (R2), predicted residual error of the sum of square statistics (PRESS statistics), error estimations (average bias error, ABE, and AAE, average absolute error), and the residual versus fitted values plot. For the vegetable oils, the best correlation was HHV = -29.5 + 77.8ρ -0.0124μ + 0.00549β (R2 = 79.6%, p-value = 0.147, AAE = 0.515, ABE = 0.005). For alkanes it was: HHV = 66.0322 – 38.3421ρ + 2.9392μ (R2 = 100%, p-value = 0.002, AAE = 0.033, ABE = 7.27 × 10-5). For alcohols; HHV = -100 + 171ρ (R2 = 86.4%, p-value = 0.070, AAE = 4.193, ABE = 0.316). These correlations could be instrumental to achieving maximum productivity with minimal utilization of energy in industry and could be extended to other liquid fuels after minor modification.
Comparism Analysis of Energy Content of Biogas and Its Physiochemical Properties
Authors: Adeleke A. I. , Olatunbosun B.E. , Borokinni F.O. , Abdulkadir B.
Published: April 2021

The correlations of energy content of biogas and physicochemical properties from cow manure and co-digestible as single and double substrates were investigated in this study. The blend that gives the highest energy, effect of anaerobic digestion on fertilizer values of the input slurry and relationship between the biogas yields were investigated. The experiment was performed at a constant temperature of 400C with a retention period of 16 days. The physicochemical properties of the slurries before and after digestion showed that the percentages of potassium, phosphorus, nitrogen and crude protein contents for all the samples batches increased. The blend of cow dung and plantain wastes in the 1:3 yielded the highest energy content and volume of biogas. This ratio can be effective for biogas production, mitigate the problems of energy shortage, fertilizer and uncontrolled waste disposal.
Prospect of high entropy alloys (HETAs) for advance application
Authors: Samuel A U , Fayomi O S I , Omotosho A.O.
Published: April 2021

Presently, HETAs are of enormous research significance in material engineering and sciences. In contrast to the traditional alloys with one and occasionally two base constituents, high entropy alloys consist of many essential elements, which are considered in excessive number compared to the conventional alloys. The arrival HETAs ignites some basic questions that challenge the hypothesis, mock-up, and preparation techniques of the traditional alloys. Here, the review of the latest studies on the prospect and essential subjects related to HETAs were provided. Besides, the novelty in the characteristics of high entropy alloys were also examined, which includes: high wear and corrosion resistance, outstanding mechanical behaviour at high temperature, superb service strength, and ductility, exceptional fracture toughness at extremely low or cryogenic temperatures, super-conductivity and super-paramagnetism. As a result of their richness of design, great structural and operational potential, they are now seen as promising materials for novel and advance applications, which should be further investigated.
Corrosion Inhibition of Aluminium Alloy by Chemical Inhibitors: An Overview
Authors: Joseph Olufunmilayo O. , Joseph Olakunle O.
Published: April 2021

Aluminium is a widely used metal in every sphere of human endeavour. Hence, its corrosion comes as no amazement. Globally, studies are being conducted to suppress this unwanted action of corrosion. Chemical inhibitors are the focus but besides chemical inhibitors, plant extracts could as well be used to inhibit the mechanism of corrosion. Polymeric inhibitors fall under this category. It is believed that these chemical inhibitors should be employed in industrial purposes. They will save millions and produce little to no toxic emission. From findings, the various techniques employed in investigation of corrosion inhibition are weight loss (the fundamental and most common method), electrochemical impedance spectroscopic (EIS) measurements and potentiodynamic polarization.
Evaluation of the use of Green Façade in Residential Buildings in Kubwa, Abuja, Nigeria
Authors: Jegede F. O. , Adewale B. A. , Ajonye G. O. , Adebajo T.
Published: April 2021

Housing development in Nigeria has constantly been carried out by the private sector as well as the government at various levels in time past. The use of sustainable elements and materials globally in recent years in meeting housing needs has indicated a progressive shift in the approach to design by architects and the built environment professionals around the world. But little has been seen in building developments in Nigeria both from the public or private sectors. The purpose of this study is to evaluate the use of the green façade as a sustainable element in constructing residential buildings. The study used Kubwa district in FCT Abuja as the study area. Primary data was derived by the administration of structured questionnaire to residents living in Kubwa. The data was analysed using the descriptive statistical tools of frequency and percentages of the Statistical Package for Social Sciences (SPSS). Findings from the research indicated that they are social and physical factors that have hindered the use of green façade in the study area. The major factors responsible for this include difficulty in getting professional help and low financial status. It is therefore recommended that both the government and the private sectors intensify efforts towards enforcing housing policies, creating incentives and delivering regular symposiums that will encourage green architectural practices such as the use of green façade in residential building and all its benefits in the built environment.
Production of Magnesium Matrix Composite and the Corresponding Mechanical Properties: A Review
Authors: Babaremu KO. , Udoh M. , Joseph O. O. , Fayomi O.S.I. , John M.E.
Published: April 2021

In this article we question the influence of the production method on the microstructure and mechanical properties of magnesium particulate reinforced composite. Magnesium matrix composite could be produced using either of the four methods discussed in this article such as ultrasonic vibration, powder metallurgy, stir casting and Shear compaction processing. The microstructural properties of the resulting composite benefited greatly from further processing when producing the composite through liquid metallurgy rout like stir casting method. The choice of ceramic reinforcement like Silicon carbide significantly improved the mechanical properties such as hardness, tensile strength but had negative effect on the ductility of the developed composite.
Effectiveness and Sustainability of Acoustic Measures in Palms Mall, Ota
Authors: Oluwatayo A.A. , Omoijiade J.A , Oluwole O.O. , Okubote F.O. , Eghobamien O.V. , Gbwefi A.M.
Published: April 2021

In this report, some of the acoustic properties and features of a shopping mall in Ogun state, Nigeria were observed and documented. The study looked into the Sustainability of materials employed for acoustic measures and the effectiveness of the acoustic measures within the mall. Under consideration were the size and shape of the space, volume, location, spatial organisation, noise zoning, insulation and isolation techniques adopted and the presence of acoustic enhancements such as banners, mufflers and absorbers. The study employed the use of qualitative field research and found that the palms mall has quite a bit to improve on in terms of acoustic treatment and that although noise pollution is not effectively combated, the materials employed can be deemed sustainable
Catalytic Pyrolysis in Waste to Energy Recovery Applications: A Review
Authors: Oyeleke Oyetunji O. , Ohunakin Olayinka S. , Adelekan Damola S.
Published: April 2021

The review examines the subject matter of catalytic pyrolysis, which is an upgrade on both the operation and output of the thermal pyrolysis process, capable of producing liquid oil products of a higher quality and yield compared to the thermal process, at reduced thermal and energetic demands. The use of catalysts plays a major role in increasing cracking activity and subsequent decomposition reactions, in attaining more desirable aromatic products. The properties, types, classes, loading mechanisms of catalyst as well as modification techniques are delved into in detail in asserting what makes catalyst efficient and effective in improving the pyrolysis process for different organic and inorganic feedstock materials. The catalytic pyrolysis of biomass substrates, which is an area less documented on was also examined, the effect of acidic zeolite catalyst on the process, mechanism, and end product of the pyrolysis process were examined in detail. Post-treatment techniques for the upgrading of liquid oil products were examined ranging from refining, filtration, distillation, and blending with conventional hydrocarbon fuels for use in different applications such as transport fuel deployment and utility generation.
Design and Development of a Mini Steam Turbine for Domestic Electric-Powered Application
Authors: Oreko Benjamin Ufuoma , Okiy Stanley
Published: April 2021

This work focuses on the design and development of a single stage De Laval impulse type of steam turbine connected to an AC generator for the purpose of generating electricity for domestic use. The system possesses several components such as turbine runner and blades, turbine casing, steam inlet nozzle and AC generator. The system is designed to work with a steam generator (boiler) fired by biogas, which is connected to the rotary (turbine blade) system via a nozzle. Factors such as steam pressure, temperature, velocity and mass flow rate of steam and nozzle angle are the key input variables that help in the development, construction and fabrication of the turbine wheel (blades and rotor). The developed mini steam turbine was simulated using solid works software and the von mises result obtained for maximum and minimum stresses of the turbine frame and stand unit were 2.725 × 105N/m2 and 4.447 × 101N/m2, respectively with yield strength of 2.5 × 108N/m2. Also, the von mises maximum and minimum stresses of the turbine blade were 3.522 × 107N/m2 and 7.064 × 104N/m2, respectively with a yield strength of 2.413 × 108N/m2. The developed mini-turbine is designed to withstand the working conditions based on the static simulation and analysis of results obtained.
Organizational Change and its Effects on Throughput: A Case Study of Lonmin Mine Shafts
Authors: Ramasu T.K. , Aigbavboa C.O. , Thwala WD
Published: April 2021

Several factors contribute to the effectiveness of an organization after an organization restructuring. Some of these factors are easily measurable while some are not. This study investigated the effect of employee attitude and perception towards organizational change (Theory of Constraints (TOC)) implementation using two Lonmin mine shafts as case studies. Sustainability of TOC was also considered. A quantitative research method was used for collecting data from two shafts in Lonmin Mine as a case study. The data was analysed using the IBM SPSS statistics 26 software. Descriptive and inferential statistical methods were performed on the data to test for statistical significance of the results. Findings from the study revealed that employees show remarkably positive attitude and perception towards organizational change. However, there is no correlation between the attitude and perception of employees and the organizational throughput.
The Effect of Ramp Location in a Strut Based Scramjet Combustor under non reacting flow field
Authors: Antony Athithan A. , Jeyakumar S. , Sivakumar R.
Published: April 2021

The scramjet engine is considered to be the high-speed propulsive system for hypersonic air-breathing vehicles. Researchers focus on various geometries of strut injectors to enhance the mixing and combustion efficiencies of the scramjet combustor. This paper reveals the non-reacting flow characteristics of various ramp locations in a scramjet combustor with strut injection. The ramps are symmetrically placed at three different locations upstream of the strut within the combustor. Air enters into the combustor inlet with Mach number 2, and the fuel is injected at the sonic velocity from the strut. The 2D supersonic flow characteristics are numerically investigated using ANSYS 18.0 software. The steady-state flow simulations are performed in this study. The flow field is modelled using RANS equations, and the k-ω SST turbulence model and default constants are chosen to investigate the flow characteristics within the combustor. The flow characteristics of the ramp based DLR scramjet combustors are compared with the baseline DLR scramjet model. The computational results are validated with the experimental data. The shock wave interaction from the ramps enhances the distribution of hydrogen in the lateral direction of the flow than the baseline strut configuration. The ramps create recirculation regions that could enhance fuel-air mixing. The ramp induced strut based DLR scramjet engine provides increased total pressure loss of the baseline DLR scramjet.