Bilingual Publishing Co. (BPC): E-Journals
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The Refractive Effect of k-Factor on Radio Propagation over Lokoja, Nigeria
No full textThe effective earth radius factor (k-factor) has a refractive propagation effect on transmitted radio signals thus making its study necessary for the proper planning of terrestrial radio links and power budget. This study was carried out over the city of Lokoja, Nigeria, using ten years (2011 to 2020) atmospheric data of temperature, pressure and humidity both at the surface (12 m) and at 100 m AGL. The data were retrieved from European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5. The k-factor yearly variation follows the same trend with minimum and maximum values obtained during dry and wet season months respectively. In addition, the highest mean value of 1.00042 was recorded in the month of August while the lowest value of 1.00040 was recorded in the month of January with an overall mean value of 1.0003. This value is less than the recommended standard of 1.33 by ITU-R. The propagation effect corresponding to k < 1.33 is sub-refractive. The implication of this on radio wave propagation, especially terrestrial communications is that transmitted wireless signal is prone to losses. This can be mitigated through an effective power budget: Choice of transmitting antenna’s height and gain, so as to improve the Quality of Service over the study area
Synthesis, Characterization and Impedance Analysis of CalciumDoped Zinc Oxide Nanoparticles
No full textThe calcium-doped ZnO nanoparticles, Zn1-xCaxO (x = 0, 0.025, 0.05, 0.075) were prepared by the solution combustion method. The synthesized nanoparticles were characterized by various techniques such as XRD, FTIR, Raman, FESEM-EDX, PL, Impedance, and UV-Vis. The Rietveld refinement of the X-ray diffractogram yields the crystalline structure and lattice parameters. Also, the XRD analysis shows that the substitution of Ca into ZnO does not alter the Wurtzite structure of ZnO. The crystallite size of the samples, calculated using the Scherer equation, was found to be between 46 nm and 92 nm. FTIR spectra detect the ZnO-related vibration modes of the samples. The FESEM morphological images suggest the spherical shape of the synthesized nanoparticles. The EDAX spectra identify the presence of Zn, Ca, and O atoms in the samples. The Raman active modes of the ZnO phase were identified by Raman spectral analysis. The analysis of Photoluminescence (PL) spectra gives information about the UV emission and other visible bands corresponding to violet, blue, and green emission representing different intrinsic defects in synthesized nanoparticles. Using UV-vis spectroscopy, the optical transparency and band gap values were examined. The energy band gap obtained by Tauc’s plot was decreased with the increase in Ca doping. Impedance analysis shows that the grain conductivity increased with the increase in dopant concentration. Contrarily, the total conductivity decreased with the increasing doping concentration due to increased grain boundary resistance. The proposed work demonstrates the changes in microstructure, electrical conductivity, and optical bandgap energy with Ca-doping. These synthesized Ca-doped ZnO nanoparticles could be promising materials for photocatalytic applications
High-Throughput CBC Mode Crypto Circuit
No full textThe objective of this study is to investigate a high-throughput cipher-block chaining (CBC) mode crypto circuit, which can be embedded in commercial home gateways or switches/routers. Concurrently, the area efficiency of block ciphers can be improved as well. However, the CBC mode encounters the problem of data dependency. To solve this issue, a data scheduling mechanism of network packets is proposed to eliminate the data dependency of input data for CBC mode pipelined crypto engines. The proposed CBC mode architecture can be applied to advanced encryption standards (AES), triple data encryption standards (3DES), and other block ciphers. In addition, to increase the throughput, deeply pipelined AES-CBC and 3DES-CBC circuits with balanced paths are proposed. With the proposed scheduling and pipelined circuits, the authors can effectively encrypt the packet data of multiple network channels at the same time. Using the proposed architecture, throughputs of 137.8 and 44.75 Gbps using a copy of pipelined AES-CBC and 3DES-CBC circuits can be achieved in TSMC 45 nm and TSMC 130 nm processes, respectively
VIKOR Method—An Effective Compromising Ranking Technique for Decision Making
No full textThe VIKOR (VlseKriterijumska Optimizacija I Kompromisno Resenje) method, which is a multi-criteria decision-making method, is examined in this paper. The VIKOR method, like other MCDM techniques such as the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), is widely used to solve complex decision-making problems in various fields such as engineering, management, and finance. This paper provides an overview of the VIKOR method, including its application areas, advantages, and disadvantages. Besides, in this survey paper, the process steps of the VIKOR method are described, including determining the decision matrix, normalizing the matrix, determining the weights of the criteria, calculating the utility and regret values, calculating the VIKOR index, and finally ranking the alternatives. By providing an overview of the VIKOR method and its process steps, this paper aims to provide a better understanding of the method and its potential application in different decision-making contexts
Assessment of the Impacts of Thunderstorm on Flight Operations at Murtala Mohammed International Airport, Ikeja, Lagos State, Nigeria
No full textThe inefficiency of the aviation industry and the persistent rise in aviation hazards have been linked to weather phenomena. As a result, researchers are looking for better solutions to the problem. The study examined the impact of thunderstorms on flight operations at Murtala Mohammed International Airport, Lagos. The data on thunderstorms and flight operations were sourced from Nigerian Meteorological Agency (NiMet) and Nigerian Airspace Management Agency (NAMA) respectively. In order to meet the research target, descriptive statistics (mean, standard deviation, and charts) and inferential statistics (Pearson’s Product Moment Correlation (PPMC) and Regression) were used. The significance level for all inferential analyses was set at 5% (0.05). The study revealed that 77.4% of thunderstorms occurred during the rainy season (April-October) while 22.6% occurred during the dry season (November-March). It also revealed some fluctuating movements of a thunderstorm in the study area. According to the findings, thunderstorms occur most frequently at the airport in June and less frequently in January and December. The study also discovered that thunderstorms at the airport are positively and significantly related to flight delays and cancellations, while the association between flight diversions and thunderstorm occurrence is positive but statistically insignificant. Furthermore, flight delays, flight diversions, and flight cancellations interact positively among themselves. The regression result of the study revealed that a 1% increase in thunderstorm occurrence leads to a 19.4% increase in flight delay, a 7.1% increase in flight cancellation, and a 4.3% increase in flight diversion. As a result, the study presented various regression models that may be utilized to make predictions. The study proposes consistent thunderstorm observation at the airport and steady forecasts using the regression models, based on the findings. However, it further recommends that pilots, air traffic controllers, and meteorologists be trained and retrained so that they can provide better and more efficient services
Using the GPS Station to Study Wind and Coastal Morpho-dynamics in North-eastern Morocco
No full textThe purpose of this work is to evaluate the potential of Global Positioning System (GPS) measurements for the monitoring of aeolian and coastal dynamics. The studied sites are the Moulouya estuary, Bouarfa’s area and Tigri Chott. The study shows that GPS is used to determine the dune kinematics and the Moulouya estuary in 3-D with an annual temporal resolution and a sub-centimeter accuracy. The GPS measurements carried out between 2013 and 2021 have shown spatial and temporal variations of the dune kinematics and Moulouya estuary. The results presented here show that the GPS measurements have the capability of continuously surveying the geomorphological entities’ kinematics with small and slow displacements and thus, they could complement conventional topometric techniques in a warning system
Fishing Production and Fishing Changes in Hong Kong after the Ground Trawl Ban of 31st December 2012: A Geospatial Evaluation
No full textFrom data published by the Hong Kong SAR (HKSAR) government in their two sole fisheries surveys of 2006 and 2016/2017, the current authors produced regional maps using spatial interpolation to more accurately describe and estimate the geographic coverage of changes in fishing production in Hong Kong waters since the ground trawl ban of 2012 December 31st. These suggest the fishing industry has adapted to smaller craft, and that fishing production increased in several areas in the period after the ground trawl ban came into effect. In addition, the maps enable a smoother assessment to be made of the geospatial changes in fishing production which have occurred since the ground trawl ban and suggest a ‘workaround’ by fishermen. In particular, small fishing craft known as sampans are able to take advantage by being more suitable vessels for areas such as narrower or shallower bays. Marine plastics pollution is also a proxy indicator of these activities, as evidenced by discarded fishing gear that includes plastic nets, floats, and other fishing boat equipment
Challenges and Trends for Multifunctional Materials
No full textMaterials science is the study of materials, their properties and their applications. As the rapid development of material science, materials tend to approach multifunctionality. Multifunctional materials are designed to perform multiple responsibilities through prudent combinations of different functional capabilities. Typically, each function contributes a distinct physical or chemical process that can deliver system-level improvements beyond the status quo. Even though some researchers have defined "smart material" as multifunctional materials (MFM), multifunctional composites (MFC), multifunctional structures (MFS), and multifunctional material systems (MFMS), the term "multifunctional materials" will be used to refer to all of these materials, composites, and structures in this paper [1]. One of the main advantages of multifunctional materials is their capacity to simultaneously accomplish multiple functions, which can decrease the need for various materials and components in the system. This benefit can result in reduced weight, higher efficiency, and superior properties and the development of multifunctional materials enables technologies that were previously impossible. The properties of multifunctional materials could vary substantially based on the applications and demands of the material. For example, the materials may respond to heat (thermal), stress & stain (mechanical), electrical, magnetic, pH, moisture, light (photonic), and molecular or biomolecular substances, and others. By incorporating these materials into composites, numerous functionalities, including self-healing, self-sensing, self-cleaning, electric conductive, thermal conductive, membrane, shape memory, and actuation, can be achieved. Therefore, multifunctional materials can improve processes and products, create several avenues to increase sustainability, and have a direct and positive impact on economic growth, environment, and quality of life
Smart Elevator Systems
No full textEffective vertical mobility is a crucial element in the design and construction of tall buildings. This paper reviews recent “smart” developments in elevator technologies and analyzes how they affect the construction and operation of tall buildings. In an approachable and non-technical discourse, it maps out, arranges, and compiles complicated and dispersed information on various elements of elevator design. It discusses hardware-based machinery, such as AC and gearless motors, machine-room-less (MRL) elevators, regenerative drives, elevator ropes, and LED lighting, as well as software-based solutions, such as destination dispatching systems, people flow solutions, standby mode, and predictive maintenance applications. Future vertical transportation models are also discussed, including multi-directional elevators, and circulating multi-car elevators. Lastly, the paper suggests fruitful avenues for further studies on the subject, such as robotics, 3D printing, and the impact of COVID-19 pandemic on elevator design
Development and Psychometric Assessment of the Dyslexia Awareness Instrument in Teachers: Dyslexia Awareness Instrument
No full textDyslexia is a specific learning disability that is neurobiological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. Teachers may not be very sure about the definition of dyslexia and generally struggle to tell the difference between dyslexic learners and slow learners. Developing the DyAwI may provide an important psychometric assessment tool in determining the awareness level of the teacher and being able to make this distinction. A descriptive, explorative design was used in this study. The study consisted of two main phases. In the first phase, in order to develop the instrument, a literature review and a pilot study on 20 primary school teachers were carried out, and in line with expert opinions, the content validity index was calculated. In the second stage, exploratory and confirmatory factor analyses were carried out to identify the construct validity and reliability. The study included 182 primary school teachers for the second stage. The KMO and Bartlett test values, which determine the suitability of DyAwI for factor analysis, were found to be 0.77 and 0.000, respectively. The overall Cronbach’s alpha value of DyAwI was .75. As a result of the assessment of its construct validity, the scale consisted of 2 factors and 14 items. The findings of the study show that the tool is reliable and sufficient. The instrument is easy to understand, and this tool can determine the dyslexia awareness levels of teachers. DyAwI could promote teachers’ awareness of dyslexia and support the early identification of primary school students with dyslexia. It is believed that, thanks to the data obtained from the instrument, teachers will be able to decide on an educational assessment of a student with reading difficulties more quickly