bluuebunny/crossref_metadata_2025 huggingface dataset:
Gain and Bandwidth Considerations for Microstrip Patch Antenna Employing U and Quad L shaped Slots with DGS and Parasitic Elements for WiMax / WiFi Applications
Authors: Raviteja G. Viswanadh , Madhan B. T. V , Kshetra Sree M. , Avinash N. , Naga Surya P. R. S.
Published: February 2022

In this research article, a microstrip patch antenna for Wireless Applications is presented. Stage by stage, the antenna is modified to achieve the desired wideband characteristics. The final proposed antenna is a combination of U and Quad L shaped slots with L shaped DGS and U shaped dual parasitic elements. Parameters S11, bandwidth and gain of the antenna versions during each stage are noted and steps are taken to improve these parameters. The end result is a wideband microstrip patch antenna working in the frequency range of 4.75 GHz to 6.15 GHz with a bandwidth of 1.40 GHz. The peak gain observed is about 7.24 dB at 5.64 GHz frequency. Simulations are carried out using HFSS software. The obtained results show that the proposed antenna can be extensively for WiFi (4.9 GHz to 5.9 GHz) and WiMax (5.3 GHz to 5.8 GHz) Applications.
Electrochemical Evaluation of AISI 304 SS and Galvanized Steel in Ternary Ecological Concrete based on Sugar Cane Bagasse Ash and Silica Fume (SCBA-SF) exposed to Na2SO4
Authors: Baltazar-Zamora Miguel Angel , Ariza-Figueroa Hilda , Landa-Ruiz Laura , Croche René
Published: February 2022

In the present research, was studied the electrochemical behavior of AISI 304 stainless steel and Galvanized Steel embedded in Ternary Ecological Concrete made with partial substitution of Portland Cement (PC) by combination of Sugar Cane Bagasse Ash and Silica Fume (SCBA-SF) in 10, 20 and 30% and exposed to a 3.5% solution of Na2SO4 as an aggressive medium. For the design of the concrete mixtures was used ACI 211.1 method. Quality control tests of fresh and hardened concrete were carried out in accordance with the ONNCCE and ASTM standards. The electrochemical evaluation was carried out for a period of 6 months, using the techniques of corrosion potential Ecorr (ASTM C-876-15) and Linear Polarization Resistance-LPR- (ASTM G59) to determine the corrosion rate Icorr. The results indicate that AISI 304 SS has a high corrosion resistance from the curing stage to the end of monitoring, with values of Ecorr lower than -200 mV and negligible corrosion levels with values of Icorr below 0.1 µA/cm2, greater protection is identified in the Ternary Ecological Concrete with replacement of 30% of PC by SCBA-SF.
Tools for Risk Management of Technical Facilities Operation
Authors: Prochazkova Dana , Prochazka Jan
Published: February 2022

The article shows the results of research directed to detection of technical facilities accidents and failures sources at their operation. The research aim is to create the effective tools for management of risks so the coexistence of technical facilities with their vicinity would be ensured throughout their life cycles. The problems solution way is based on the simultaneously preferred concept, in which the safety is preferred over the reliability.  Respecting the present knowledge on technical facilities´ safety and the lessons learned from the past technical facilities accidents and  failures, the causes of which were connected with their operation, two tools are developed:  Decision Support System and Risk Management Plan that were reviewed by experts and tested in practice.
Influence of Performance Appraisal on Performance of Civil Servants in Kenya
Authors: Elhadi Yahya Idriss
Published: February 2022

This article is part of a doctoral project entitled “Results-Based Management and Performance of Civil Servants in Kenya”. The purpose of the article is to determine the influence of performance appraisal on performance of civil servants. During the last three decades performance appraisal has become a popular instrument in public sector reform agenda under the New Public Management which is results-driven. Its application has since become an important human resource management practice in the public sector performance management systems. The underlying aim is to foster organizational and individual efficiency and effectiveness in the public sector. Applying both descriptive survey and case study designs with a mixed research strategy, the study found that performance appraisal has a significant positive influence on performance of civil servants in Kenya. This means that, when performance appraisal process is effective, civil servants learn about themselves; gaining sense of personal worth, become more knowledgeable about their tasks, and more imperatively they learn about what are mostly valued by the employer. The study recommends for pragmatic use of performance appraisal since has significantly and positively influenced the performance of civil servants in Kenya.
Seven-Dimensional Spacetime in the Planck Vacuum Theory and the Structure of the Electron and Proton Cores
Authors: Daywitt William C.
Published: February 2022

The electron and proton cores in the Planck vacuum (PV) theory are reccognizable elementary particles that obey the manisestly covariant Dirac equation and that are coupled to the PV state. (This statement and similar statements to follow also apply to the electron-core and the proton-core antiparticles.) This paper derives the corresponding 2x1 spinor-wavefunction equations for these cores, leading to a 7-dimensional spacetime that consists of two 4-dimensional spacetimes, the result of a bifurcated vacuum state. Both the electron and proton cores contain structure, where the electron core structure is orders of magnitude smaller than the proton-core structure.  The core structure is easily reccognized in the calculations, as is particle-antiparticle annihilation. The difference between the electron and proton cores and their electron and proton particles is that the latter contain radiative corrections.
Heat Transfer Augmentation
Authors: Asianuaba Ifeoma B.
Published: February 2022

This article presents a brief review of various methodologies applied for heat transfer enhancement in laminar flow convection regime. Experimental setup for laminar flow convection heat transfer enhancement using insertions has been explained along with the associated results. Nusselt’s number is found to be a key parameter for investigatigation in order to perceive the enhancement in heat transfer. Similarly, the magnetohydrodynamic mixed convection heat transfer enhancement technique has also been explored. The results of isotherms and fluid flow parameters are discussed which directly affect the heat transfer coefficient. This review article complements the literature in related field and thus will be helpful in order to carry out further experiments in heat transfer enhancement in future.
Determination of Temperature-Moisture Relationship by Linear Regression Models on Masonry and Floor, Kruja, Albania
Authors: Xhexhi Klodjan Anesti , Maliqari Andrea , Meunier Paul Louis
Published: February 2022

Kruja is a middle range city located in the center of Albania. The city of Kruja dates back to its existence from the  V-VI century and extends to the city around the VI and IX centuries. It becomes the first capital of Albania in the  XI-th century, specifically in 1190. This paper is going to deal with only two groups of buildings which are an integral part of the historical city of Kruja, the historical dwellings (XVIII century) and socialist ones (1960-1970).The aim of this paper is to analyze through linear regressions the relation between two parameters: moisture level and temperature of the indoor walls and floors of the historic and socialist buildings in the city of Kruja. Three types of historic dwelling and three types of socialist apartments have been analyzed, relatively uniformly oriented. The measurements with specific instruments are done in the same day, during three hours. The degree of reactivity is different for both groups of buildings. The historical buildings are more sensitive to temperature rise. They respond invers to it (as the temperature rise, the level of the moisture decreases), with a higher coefficient than socialist ones and appear to be more efficient in reducing the moisture level, despite the average humidity level is higher. This paper takes into consideration also the analyze of the materials of the construction for both categories. If the level of the moisture is reduced, the buildings will be improved and the quality of life indicators of the inhabitance will be improved too.
Pressure Control of HVAC System for Corona Virus
Authors: Chung Samuel W. , Jo Jeong Je
Published: February 2022

Corona Virus is deadly spread out to thousands of healthy people and so strong as to infect to the surrounding people after people.  We must keep the deadly virus indoor as much as we can.  How?  We must not allow the indoor air already contaminated to leak out to the atmosphere, which will transmit to other people. The new virus is so strong and so fast to transmit, it will spread within a few seconds to thousands of people and became patients immediately. To solve the problem, we must build a pressure vessel to keep the virus inside the vessel and not to leak outside. It should be a negative pressure compare to the atmospheric pressure. Another words, is to keep the indoor pressure lower than atmospheric pressure, so the contaminated indoor pressure is lower than outdoor pressure. It is a part of a traditional HVAC operation. This article shows step by step procedures of HVAC system design procedures, with emphasis of the air duct system design. Care must be taken to keep close attention to the maintenance of the system.
Recycled ABS Polymer Doped with Outdated Lansoprazole as a Corrosion Protection Composite Coating for Mild Steel in Chloride Solution
Authors: Viveros Sandra , Menchaca Carmina , Hernandez Miguel A. , Covelo Alba , Uruchurtu Jorge
Published: February 2022

Acrylonitrile-butadiene-styrene (ABS) is a common waste polymer by-product from industry. Outdated medicines are usually discarded and could be a valuable asset for other applications such as metallic corrosion inhibition. The aims of the present work is to manufacture a recycled ABS polymer doped with outdated lansoprazole medicament as a corrosion protection composite coating. It was applied to mild steel and immersed in chloride solution, and evaluate its possible corrosion protection properties using different electrochemical techniques. The manufactured coating presents good corrosion protection properties showing an 80% efficiency as a function of time of immersion in the aggressive solution.
Solar-Energy Innovative and Sustainable Solution for Freshwater and Food Production for Lake Titicaca Islands
Authors: Bashitialshaaer Raed
Published: February 2022

Drought and scarcity of water resources require innovative and sustainable solutions to secure water availability for poor people. Choice of solar energy for desalination is a promising and sustainable cost-effective alternative for improving high quality water supply. Today, almost all Latin American countries use different desalination technologies except for Bolivia. Bolivia has an arid to semiarid climate and suffers from salinity problems especially the Altiplano area. Thus, there is a need to introduce innovative solution using latest technologies such solar desalination at locations with scarcity of freshwater. This study suggests implementing a small desalination plant of about 10 m3/day as a demonstration plant and then successively extending the capacity. As well, it is suggested to build a solar energy system with bigger capacity to cater not only for the desalination plant, but also the excess energy to be benefit for homes, roads lighting, and other important purposes for the local community to improve life standard of the people.
Fresh and Hardened Properties of Styrene Butadiene Rubber (SBR) Modified Concrete
Authors: Qadri Muhammad Ahmed , Hameed Huzaifah , Bhutta Osama
Published: February 2022

The durability of concrete has been studied ever since it was first used. Researchers have incorporated several materials to make concrete strong and durable. This research focuses on the infusion of styrene butadiene rubber polymer (SBR) as a partial replacement of cement and studies its effects on fresh and hardened properties of concrete. Samples were prepared using partial replacement of SBR in proportions of 0%, 5%, 10% and 20%. Results showed that the fresh density of concrete decreased with the addition of SBR whereas the trends of workability showed an increase with cement replacement. Compressive strength increased at lower percentage replacements however the flexural and tensile strength increased till 15% SBR addition after which it decreased. The total porosity in terms of water absorption decreased which makes SBR modified concrete feasible for concretes exposed to moist conditions and the decreased porosity would increase its durability against chloride induced corrosion.
Application of Machine Learning for Diagnosis of Head and Neck Cancer in Primary Healthcare Organisation
Authors: Olabode Olatunbosun , Adetunmbi Adebayo O. , Akinbohun Folake , Akinbohun Ambrose
Published: February 2022

Head and neck cancers (HNC) are indicated when cells grow abnormally.  The disturbing rate of morbidity and mortality of patients with HNC due to late presentation is on the increase especially in Africa (developing countries). There is need to diagnose head and neck cancer early if patients present so that prompt referral could be facilitated.  The collected data consists of 1473 instances with 18 features. The dataset was divided into training and test data.  Two supervised learning algorithms were deployed for the study namely: Decision Tree (C4.5) and k-Nearest Neighbors (KNN). It showed that Decision Tree outperformed with accuracy of 91.40% while KNN had accuracy of 88.24%. Hence, machine learning algorithm like Decision Tree can be used for diagnosis of HNC in healthcare organisations.
Comparative Analysis of Water Drive, Gas Drive and Natural Drive Mechanism for Oil Production using Alwyn North Field as a Case Study
Authors: Amadi Azubuike Hope , Raphael Okeke , Ebube Orisa F.
Published: February 2022

In-situ Crude oil can be produced through several drive mechanisms of which the choice of specific drive mechanism is dependent on several key performance tools. This study examines the Alwyn North field and presents a comparative analysis for producing crude oil using water drive, gas drive and natural drive or depletion drive. The Eclipse Simulator was used to simulate different scenarios of well placement and performance tools such as FOPR, FPR, FWCT, FGOR and FOE was used during simulation to compare the outcomes of the well placement. Economic analysis which is key in decision making was carried out using economic tools such as Gross Profit Margin (GPM), Net Present Value (NPV), Payback Period, Internal Rate Return (IRR) and Profitability Index (PI). The payback period for water injection was 2.1years and 1.99years for gas injection. IRR was 53% and 48% for water and gas injection development schemes respectively and Profitability Index for water injection was 1.73 and 1.36 for gas injection. These economic tools helped to arrive at a conclusion of best drive mechanism for the production of the field.
Moment and Stress Analysis Solutions of Clamped Rectangular Thick Plate
Authors: Ibearugbulem O. M. , Onyeka Festus Chukwudi
Published: February 2022

The bending solutions of rectangular thick plate with all four edges clamped (CCCC) were investigated in this study. The basic governing equations used for analysis are based on third-order shear deformation plate theory analysis under uniformly distributed load. Using a formulated total potential energy equation, the three coupled general governing differential equations for the determination of the out of plane displacement and shear deformations rotation along the direction of x and y coordinates were obtained. These equations as obtained are solved simultaneously after minimization to determine the coefficients of displacements of the plate and other the mentioned functions. By solving these equations, the analytic solutions of rectangular thick plate with all four edges clamped were derived. From the formulated expression, the formula for calculation of the maximum deflection, moment, stress and in-plane displacements were deduced. The proposed method obviates the need of shear correction factors, which is associated with Mindlin’s theory (FSDT) for the solution to the problem. Moreover, numerical comparison shows the correctness and accuracy of the results.
Threshold Segmentation and Watershed Segmentation Algorithm for Brain Tumor Detection using Support Vector Machine
Authors: Hatcholli Seere Santhosh Kumar , Karibasappa K.
Published: February 2022

Brain Tumor is a dangerous disease. The chance of the death is more in case of the brain tumor. The method of detection and classification of brain tumor is by human intervention with use of medical resonant brain images. MR Images may contain noise or blur caused by MRI operator performance which can lead to difficult in classification. We can apply effective segmentation techniques to partition the image and apply the classification technique. Support Vector machine is the best classification tool we identified as part of this work.  The use Support Vector Machine show great potential in this field. SVM is a binary Classifier based on supervised learning which gives better result than other classifiers. SVM classifies between two classes by constructing hyper plane in high-dimensional feature space which can be used for classification.
Towards Sustainable Composite Building Material: Integrating Lime with Slag for reduced mortar Thermal Conductivity
Authors: Olaniyan Sule Adeniyi
Published: February 2022

Lime Based Mortar became very popular due to its outstanding features of flexibility, permeability and low carbon emissions. However, lime’s characteristic delayed setting, late hardening time, low mechanical strength, among others, overshadowed significance of its outstanding features, thereby putting its overall use into decline, particularly, with the 19th century Portland Cement discovery. This study therefore aims at reviving lime usage through a sustainable lime composite, by integrating an industrial by-product, Ground Granulated Blast Furnace Slag (slag) with lime, in form of lime-slag mortar, with a view to reducing the mortar thermal conductivity. The methodology involved mortars with the same Binder/Aggregate (B/A) mix ratio (1:3) using five separate volumetric compositions of ‘slag-lime’ binders (i.e. 1:1, 1:2, 1:3, 2:1 and 3:1). Physical properties of the mortars involving their Water/Binder (W/B) ratios, Air Contents and Bulk Densities were recorded. Comparative evaluations of the compositions in hardened state, involving thermal conductivities were carried out at specific intervals through a twelve-month curing period. These were partly monitored through assessments of the composites’ microstructural behaviours over a six-month period. Results of the investigation show that addition of slag to mortars facilitate slightly larger pores with increased porosities. However, these effects are minimal (i.e. from 23.42% to 25.37% porosity) when slag content is at equal volumetric content with lime. A general reduction (not in a linear trend) in the thermal conductivities of the mortar with increasing slag content was observed, cumulating in 25% decrease in the composites having thrice volumetric content of slag, relative to lime. Composite’s reduced thermal conductivity would be of utmost importance in construction especially, where material’s limited thermal conductivity property is of utmost importance.
Evaluation of Strength Properties of Subgrade Materials Stabilized with Bio-Enzyme
Authors: Raheem Bamidele S. , Oladiran G. F. , Oke D. A. , Musa S. A.
Published: February 2022

In the recent studies many chemical have been emerged and used as stabilizing agent. One of such chemical (Bio-enzyme) was used in this study as a stabilizing agent. Bio-enzyme is prepared locally from fermented vegetable and fruits waste. These products are natural, nontoxic, non-corrosive, nonflammable liquid and environmentally harmless. In this research, Bio-enzyme was prepared and used in varying proportion to stabilize laterite samples collected from different locations. Detailed laboratory experiments (Classification tests and CBR) were conducted to evaluate the effects of Bio-enzyme at varying dosage after 24 hours of curing of specimens. The percentage passing through sieve No. 200(75 micron) was less than 35%., according to ASHTO and clause 6201 of Federal Ministry of Works and Housing (F.M.W & H) Specification Requirements, sample A is (A-2-5), sample B is (A-2-4) while sample C is classified as A-2-6 and they are silty or clayed gravel and sand. Sample A is a good subgrade, subbase or base materials based on highest CBR values (at 20% bio-enzyme dosage, Sample A (102.50%) and sample B (69.40%) & at 10% sample C (33.2%). Sample B can also be used as subgrade or subbase materials where light traffic is considered and sample C is suitable as filling materials as evident in their CBR value. It has been observed that Bio-enzyme treated soil shows significant improvement in terms of the dry density and CBR value. Presence of Bio-enzyme in the soil samples led to increase in the C.B.R by 10-20% as compared to the control). However, it is recommended that assumption should not be made that Bio-enzyme is considered suitable for all type of soil and long term effect of it should also be examined.
Assessment of Spatial Prediction Techniques Accuracy for Elevation Determination in Akure South Local Government, Ondo State
Authors: Ijaware Victor Ayodele , Adeboye Adebayo T.
Published: February 2022

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a cooperative effort between NASA and Japan's Ministry of Economy Trade and Industry (METI), with the collaboration of scientific and industry organizations in both countries. The ASTER instrument provides a more robust remote sensing imaging capability when compared to the older Landsat Thematic Mapper. This paper deals with the accuracy assessment of elevation data obtained using ASTER from each of the eleven (11) selected extrapolation/interpolation algorithms: Inverse Distance Weighting, Natural Neighbor, Spline Regular, Spline Tension, Universal Kriging, Empirical Bayesian Kriging, Topo to Raster, global (trend surface), local polynomial, kernel interpolation with barriers and radial basis functions in Digital Elevation Model (DEM) surface creation. The data were compared with reference to ground control points of differential GPS measurements in the study area. The error statistics were generated between DGPS measurements and Extracted elevation data from each selected interpolation method. It was observed that Spline Regular Interpolation shown the best overall accuracy of ±11.520m when elevation data extracted from Inverse distance weighting, Natural Neighbour, Spline T, Topo to Raster, Universal Kriging, Empirical Bayesian kriging, Global polynomial interpolation (GPI), local polynomial interpolation (LPI), Radial basis function and Kernel interpolation of ±15.170, ±14.340, ±12.336, ±13.551, ±14.707, ±13.711, ±15.363, ±13.964, ±13.590 and ±15.376 respectively when compared with elevation values from GPS method. The study recommends capacity building in the form of workshop, training, and flexible integration of point elevation data to DEM.
Introduction into the Extra Geometry of the Three–Dimensional Space I
Authors: Szalay Istvan , Szalay B.
Published: February 2022

Using the theory of exploded numbers by the axiom–systems of real numbers and euclidean geometry, we introduce a geometry in the three–dimensional space which is different from the euclidean-, Bolyai – Lobachevsky- and spherical geometries. In this part the concept of extra-line and extra parallelism are detailed.
Smart attendance system using Convolution Neural Network and Image Processing
Authors: ChayaDevi Senigala Kuruba , Agnihotram Vamsi
Published: February 2022

Smart attendance maintenancesystem has been a research topic from past a fewdecades; each method has its own disadvantages and advantages.An algorithm using Convolutional Neural Network and Image processinghas been proposed in this paper to overcome the disadvantages of the previous algorithms. Image recognition is playing an important role in the modern living like driver assistance systems, medical imaging system, quality control system to name a few. An Artificial Neural Network along with image recognition used to enhance the reliability of the attendancesystem. One such update used here is CNN.Deep learning has been an emerging technology hence opted to implement the smart attendance system.The implementation basically consists of three components : 1)Face scanning and detection using HAAR cascade method 2)Training the CNN-ANN model 3)Recognize the face  and update the attendance .The main motivation of our work is to merge three of the emerging technologies : Machine learning , Image Processing and IOT . Key advantage of this implementation is that a deep learning model increases its accuracy with more epochs of training andit optimizes the run time.
Comparative Analysis of the Rebound Hammer and Pullout as Non-Destructive Method in Testing Concrete
Authors: Onyeka Festus Chukwudi
Published: February 2022

A comparative analysis between Rebound Hammer and Pullout method in testing concrete was conducted in this study. Experimental analysis were carried out to compare the correctness between the two testing method in estimating the strength of concrete. Different cube (cubes of 175 x 175 x 175) samples were prepared using two mix designs of 1:2:4 and 1:3:6 with a constant w/c ratio of 0.45 and were tested at 7, 14, 21 and 28 days. The rebound hammer readings had a correlation coefficient of 0.695 while the pullout had a correlation coefficient of 0.725 for the 1:2:4 mix and the rebound hammer readings for 1:3:6 was 0.724 and that for the pullout was 0.675. From the results obtained, it is observed that the non-destructive testing methods were correlated with the compressive strength results which showed that a higher correlation existed between the Rebound Hammer and the compressive strength than the Pullout. Statistical analysis of the results obtained showed that there was no significant difference between the means of the two methods for both mix at a 0.05 level of significance. However, Rebound hammer method can be recommended as it provides a quicker, less-expensive means of checking the uniformity of concrete even though it shows less sensitivity as concrete matures, unlike the Pullout test in which measuring strength is affected by the arrangement of the embedded insert, the dimensions of bearing ring, the depth of embedment, the concrete age and the type of aggregates uses in concrete.
The Fine Structure Constant and Radiative Corrections for the Electron and Positron Cores as Viewed in the Planck Vacuum Theory
Authors: Daywitt William C.
Published: February 2022

The present paper derives the radiative corrections for the electron and positron cores in the Planck vacuum theory, leading to the electron and position particles in a 7-dimension spacetime. The physical meaning of the fine structure constant is twofold: it is the ratio of the electron spin coefficient to the electron-core spin coefficient; and it is the probability that an electron or positron will emit or absorb a photon. The nature of this photon defines the spin quanta in the PV theory. Results suggest that the Feynman and Schwinger QED calculations refer to the PV state. Finally, the closed-loop electron-positron pairs in the Feynman diagrams are explained.
Experimental Validation of a Forced-Circulation Solar Water Heating System Equipped with Flat-Plate Solar Collectors – Case Study
Authors: Maraj Altin
Published: February 2022

This paper represents the comparison and the validation of results obtained from the simulation, towards the measurements performed in a forced-circulation solar water heating system equipped with flat-plate solar collectors. Polysun tool is used to model and to simulate the considered system during an annual time period. Mathematical models are used to calculate the required sensible heat, thermal yield from the flat-plate collector area, delivered energy to the thermal consumer, efficiency of the collector area, efficiency of the system, and the solar fraction. To validate the model, experimental data recorded in time intervals of 5-minutes in a trial installation are utilized. Statistical test errors (epsilon, MBE, MPE, RMSE, and R^2) are used to compare the values obtained from the simulation and measurements. Between them, a very good fit is noticed.
New Thermodynamics: Rethinking the Science of Climate Change
Authors: Mayhew Kent W.
Published: February 2022

Statistical analysis shows that climate change is due to human activities. The accepted reason being the greenhouse effect, which is based on the erroneous assumption that homonuclear gases are opaque to thermal energy. The reality is that all polyatomic gases absorb and then radially radiate thermal energy, as proven by their heat capacities. The greenhouse effect, then becomes secondary. Thermal energy generated by human activities is part of Earth’s anthroposphere which is where climate change is measured. Such human-generated thermal energy is absorbed by all our atmosphere’s polyatomic gases, which is then radially radiated by those very gases. Therefore, our whole atmosphere forms Earth’s thermal blanket, and human’s activities becomes the root cause of climate change. Our Sun’s influx starts outside of Earth’s thermal blanket, with much of its visible light reaching Earth’s surface. However, the majority of the Sun’s insolation is at thermal wavelengths, which are readily absorbed by Earth’s atmosphere, and whose energy are then radially radiated by its polyatomic gases.
Froth Flotation Beneficiation a Sure Way to Value Addition to Arufu (Nigeria) Zinc Ore Towards Smelting Grade Concentrate Production
Authors: Alabi Oladunni Oyelola , Bodede Olanrewaju Rotimi , Popoola Taiwo Paul
Published: February 2022

Froth flotation of Arufu ore was carried out at varying particle sizes after characterization. Fifty (50) kilogram crude sample of the ore was sourced from Arufu zinc mine in Arufu town of Nassarawa state, Nigeria. The whole sample was crushed out of which five (5) kilogram was sampled out using random sampling method. One kilogram each of the resulting sample was then ground and sieved to three particle sizes viz; 63 µm, 90 µm and 125 µm. Chemical analysis of the representative sample of the sourced ore was carried out using Energy Dispersive X-Ray Fluorescence Spectrometer (ED –XRF). 250 grams of the 63 µm sample was charged into Froth flotation cell mixed with water at a ratio of 1:4 to form slurry. The Slurry formed was condition to a pH of 9, while other froth flotation reagents were added one after the other. This resulted in froth and depressed samples, which were dewatered after 24 hours and samples picked for compositional analysis. The procedure was repeated for 90 µm and 125 µm. The characterization of head sample revealed that the ore contains predominantly 36.80%ZnO (26.29% Zn), 31.1 % SiO2 alongside other trace mineral as gangue in the ore. However, Froth flotation studies of the ore at varying particle size revealed that, appreciable amount of mineral of interest (ZnO) was lost to the tailing at sieve sizes 63 µm and 90 µm. This was attributed to over-grinding above the ore’s liberation size phenomenon which has been proven to have adverse effect on the mineral’s quality and overall separation efficiency. It was concluded that the froth flotation is best carried out at a particle size of 125 µm, pH of 9, using potassium ethyl xanthate (PEX) as frother to yield concentrate grade of 50.21 % ZnO (35.93 % Zn) at a recovery of 46.3%. This was re – cleaned to yield high grade of 82.36%ZnO (66.42%Zn). The re – cleaned concentrate produced falls within the standard requirement of 65 % Zn needed as a charge into the blast furnace for Zinc metal production.
Review of Multilevel Inverters and Their Control Techniques
Authors: Tashiwa Ibrahim Emmanuel , Dung Gyang Davon , Adole Benson Stephen
Published: February 2022

Multi-level inverter is attaining higher AC power using a series of power semiconductor switches with numerous lower voltage DC sources to implement the power conversion by synthesizing a staircase voltage waveform. Sources like super capacitors, batteries, solar panels and other renewable energy voltage sources make up the multiple DC voltage sources. This work looks at the advantages and likely disadvantage of multi-level inverter, highlighting some of the shortfalls of existing inverter topologies while considering the effects of emerging Hybrid MLI Topologies. Hence this review paper proposes a distinctive seven level cascaded H-bridge multi-level inverter configuration in which the POD PWM technique is adopted. This design would potentially redress the problems inherent in other inverter circuit topologies reviewed.
Uncertainty Approaches for Solving Generalized Machine Maintenance Problem
Authors: Abass Samir Abdou , Abdallah Asmaa S. , Elsayed Marwa Shehata , Ahmed Eman Massoud
Published: February 2022

In this paper, the generalized machine maintenance problem is formulated as linear programming model. The objective is to maximize the percentage production hours available per maintenance cycle of each machine.  Data in many real life engineering and economic problems suffers from inexactness. There are different approaches to deal with uncertain optimization problems. In this paper two different approaches of uncertainty, Fuzzy programming and rough interval programming approaches will be introduced. We deal the concerned problem with uncertain data in coefficients of the constraints for the two approaches. A numerical example is introduced to clarify the two proposed approaches. A comparison study between the obtained results of the two proposed approaches and the results of interval approach for Samir A. and Marwa Sh [3] will be introduced.
Rogowski Coils for Design of Energy Meters for Nigeria Power Market
Authors: Iloh John Paul I.
Published: February 2022

Proper metering of electricity consumption is the optimal way for effectively recovering revenues for power supplied to the consumers by the distribution companies (DISCOs). In Nigeria, the situation is quite problematic due to inadequate metering of the consumers. As a result, huge amount of revenues due to the DISCOs are left uncollected leaving the DISCOs to resort to estimated billing system. To solve this problem, this paper proposes a locally made digital energy meter built from locally available materials in Nigeria. Specifically, this work proposes to use an inexpensive rogowski coil wound from made-in-Nigeria wire on an improvised air core material as the current sensing element to be used in the meter. Two rogowski coil samples wound from SWG 36 and SWG 25 wires having resistances of 50ohm and 1.3 Ohms respectively were subjected to repeated experimental tests in order to study their characteristic behavior under varying load current scenarios. The results obtained were used to characterize the coils behaviors by using the basic fitting tool in MATLAB graphing window to generate the optimal equation representing the coils’ behaviors.  The equations so obtained are intended to be used to program the microcontroller for implementation of the Digital Energy Meter algorithm adopted in the proposed design. Results from the experiment showed that the coil with lower resistance exhibited better linear response while the coil with higher resistance was better optimized by quadratic and cubic polynomials. These findings serve as design guide for local fabrication of the rogowski coils to be used in the proposed digital energy meter being developed for the Nigerian power market.
Machine learning Clustering Algorithms Based on the DEA Optimization Approach for Banking System in Developing Countries
Authors: Mirmozaffari Mirpouya , Boskabadi Azam , Azeem Gohar , Massah Reza , Boskabadi Elahe , Dolatsara Hamidreza Ahady , Liravian Ata
Published: February 2022

Machine learning grows quickly, which has made numerous academic discoveries and is extensively evaluated in several areas. Optimization, as a vital part of machine learning, has fascinated much consideration of practitioners. The primary purpose of this paper is to combine optimization and machine learning to extract hidden rules, remove unrelated data, introduce the most productive Decision-Making Units (DMUs) in the optimization part, and to introduce the algorithm with the highest accuracy in Machine learning part. In the optimization part, we evaluate the productivity of 30 banks from eight developing countries over the period 2015-2019 by utilizing Data Envelopment Analysis (DEA). An additive Data Envelopment Analysis (DEA) model for measuring the efficiency of decision processes is used. The additive models are often named Slack Based Measure (SBM). This group of models measures efficiency via slack variables. After applying the proposed model, the Malmquist Productivity Index (MPI) is computed to evaluate the productivity of companies. In the machine learning part, we use a specific two-layer data mining filtering pre-processes for clustering algorithms to increase the efficiency and to find the superior algorithm. This study tackles data and methodology-related issues in measuring the productivity of the banks in developing countries and highlights the significance of DMUs productivity and algorithms accuracy in the banking industry by comparing suggested models.
Analysis of DVB-T2 and LTE Networks Co-Existence in the Digital Dividend Band in Nigeria
Authors: Ashigwuike Evans C. , Umar Sadiq A. , Okpanachi Moses Stephen O.
Published: February 2022

This paper, present results of the analysis of DVB-T2 and LTE network co-existence in Nigeria. The Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) used to analyse the co-existence. The findings of the study reveals that the blocking interference is the dominant effect and to ensure that the probability of interference is below the threshold of 5%. It is mandatory to decrease the transmission power of the LTE from 196mw to 25mw. Consequently, the protection ratio for DVB-T2 and LTE should be maintained for a seamless co-existence.
Numerical Analysis of Adhesive Joints with Bi-Layered Adherends
Authors: Sayegh Ahmed Hasan , Almitani Khalid , Othman Ramzi
Published: February 2022

Improvement of joint quality has always being a call for concern in an assembled component due to numerous application of such components in immense industrial sectors such as aerospace and automotive industries, electrical/electronic industries etc. With this in mind quite a vast research had been carried out and still on going to enhance the characteristics of various parts that makes up an assemble and the complete assemble itself. Part of the research carried out fixated on adhesive bonded joint of different geometrical designs such as L-shape, single-lap, double-lap, tubular, T-shaped, stepped and scarf joints etc. Focusing on single –lap joint due to the simplicity of the design geometry and their ease of fabrication, various forms of arrangement have been researched on. But owing to its untimely failure, caused by high strength concentration in the overlapping areas and some other parts that are delicate to peel damage various forms of design geometry have been adopted ranging from tapering, stepping and wavy lapping of overlapping layers in order to reduce or mitigate the stress concentration for an improved load bearing ability. Due to a lot of challenges being faced with difficulty in fabrication, this study focused on double layer single-lap joint. Its harmonic response when subjected to external dynamic loading was investigated with the use of Ansys finite element analysis. The numerical analysis was carried out on various forms of adhesive-adherends arrangement, and from the harmonic response obtained it showed that the double layer single-lap joint have improved load bearing capacity as compared with other geometrical designs.
Experimental Investigation of Dynamic Properties of Fiber-Reinforced Tire-Derived Lightweight-Aggregate Concrete
Authors: Tehrani Fariborz M. , Masswadi Nazmieh A. , Miller Nathan M. , Sadrinezhad Arezoo
Published: February 2022

This paper presents the results of an experimental study to investigate dynamic properties of polypropylene fiber-reinforced concrete beams with lightweight expanded shale (ES) and tire-derived aggregates (TDA). The mixture design followed past experiences in combining ES and TDA to enhance toughness and energy absorption in flexural behavior. The new mixture also contained 2% fiber by volume to improve such properties further. Experiments included compressive testing on cylindrical specimens as well as flexural testing on rectangular specimens to verify mechanical properties of fiber-reinforced tire-derived lightweight aggregate concrete (FRTDLWAC) subject to static loading. The results of these experiments confirmed reduction of mechanical strength due to addition of TDA and improvements in flexural strength due to fiber reinforcement. The dynamic testing included non-destructive impact loads applied to flexural specimens using a standard Schmidt hammer. A high-speed camera recorded the response of the system at 200 frames per second to allow detailed observations and measurements. Interpretation of energy-based dynamic results revealed that TDA enhances energy absorption through damping in flexural behavior. Results also indicated that fiber reinforcement reduces the amount of absorbed dynamic energy, even though; it enhances the absorbed strain energy due to crack bridging effect.
New Method of Calculating the Attainable Life and Reliability in Aerospace Bearings
Authors: Gloeckner Peter , Sebald W.
Published: February 2022

The aviation industry made significant progress improving reliability, efficiency and performance throughout the last decades. Especially aircraft engines and helicopter transmission systems contributed significantly to these improvements. The kerosene consumption decreased by 70 % and the CO2 emissions due to air transport decreased by 30 % per passenger kilometer within the last 20 years. Simultaneously, the flight safety was increased with aircraft engine in-flight-shut-downs as low as 1 ppm and „unscheduled engine removals” as low as 4 ppm. Flight safety is equal to the reliability of the systems in service. Failure of these systems directly leads to exposure of human life. Among the most critical aviation systems are aircraft engines including the rolling element bearings which support the rotors. A serious damage to the aircraft engine main shaft bearings during flight requires shout-down of the engine to avoid a further damage escalation subsequently leading to engine fire. Today, it is a requirement for aircraft to operate with one engine shut down. However, each in-flight-engine-shut-down typically is connected with flight diversion or abort and immediate landing. Inflight-shut-downs translate into increased risk for passengers and crew and substantial on cost. Therefore, rolling element bearings for aircraft engines are developed – similar to other aircraft engine components – targeting a reliability of nearly 100 % over an operation time of more than 10 000 hours prior to overhaul. To achieve this requirement despite the extreme operating conditions such as high speed and temperatures occurring in gas turbines, special high-performance materials are used for the rolling bearing components which are partially integrated in surrounding engine parts like shafts and housings. These special conditions - deviating from conventional industrial rolling element bearing applications - are currently not sufficiently considered in the standardized method of calculating the bearing life per ISO 281. A new method of calculating the attainable life of rolling elements bearing in aerospace applications is presented. This method considers the special aerospace conditions and materials and thus enables a higher reliability of the theoretical analysis and life prediction.
Sensitivity Based Approach for the Optimal Sizing and Allocation of Distributed Generation in a Radial Network
Authors: Maduforo Paul C. , Emechebe Jonas N. , Eronu Emmanuel M. , Benson Stephen Adole
Published: February 2022

Electric power has remained a basic essential for the advancement of any nation's economy. Increasing human exercises because of innovative advancement combined with populace development has made the interest for power dramatically increasing continuously, subsequently widening the gap between power generated and the demand by the consumers. This work provides sensitivity based method for the allocation of a distributed generation in a distribution network aimed at improving the voltage profile and reduce power loss in the quest to narrow the gap between power generated and that demanded by the consumers. Using the Loss sensitivity method, a DG of 153kW was allocated to bus 5 that sees a power reduction of 46% with voltage profile improved within constraints. Voltage sensitivity index was calculated at all nodes. Bus 17 was found to have the minimum VSI. In this case DG sizes were taken in step size of 17.5kW starting from 30 kW till 170 kW at different power factors of 1.0, 0.9, 0.85, and 0.8. The DG sizes were tested at the selected power for various DG sizes. 135kW DG at unity power factor was installed. After comparing the two methods it can be concluded that loss reduction in loss sensitivity method is more and it is better in terms of selecting the optimal location for the placement of DG. For the purpose of sizing the voltage sensitivity analysis index method is a better option.
Multimodal Traveller Information System using both Web-Based Design Program and Traffic Analysis for Akure Metropolis
Authors: Aderinola Olumuyiwa Samson , Laoye Abdulrahman Adewalee , Akinade Adebayo I.
Published: February 2022

A Traveller’s Information System integrated with traffic condition which can provide vital information to the users of the system is such a powerful tool in transportation planning. In this study, web-based multimodal advanced traveller information system was developed, which supplies information to trip makers within Akure metropolis and major cities with similar traffic condition. Traffic count was also taken on five roads which most of the transportation company’s vehicle ply so as to check for the traffic condition of the roads. The system provide information such as the available route from the origin of the traveller to his or her destination, the travel time, distance of each route, closest facilities like hotels, hospitals, airline services, airport terminal, departure time, departure time, arrival time and fare. The traffic count carried out revealed that Oyemekun road has the highest volume of traffic followed by Akure-Ado road while FUTA North gate road gives the least volume of traffic. The reason for the highest volume of traffic recorded at Oyemekun road is as a result of it location close to the CBD (Central Business District) while the lowest volume of traffic recorded for FUTA North gate is as a result of it location almost at the outskirt of the town. The web-based multi-modal traveller’s information system developed will help trip makers in Akure metropolis minimize the cost of their trips, by reducing travel time, energy consumption, and transport fare. Travellers are advised to embark on their journey earlier than the peak periods so as to avoid delay.