Volume 27, No. 3 (2021)
Articles
HETEROGENEOUS CATALYSIS USING BENTONITE-SUPPORTED Fe-Co-Ni TRIMETALLIC NANOPARTICLES
ADERIBIGBE FATAI ALADE(1*), ADEWOYE TUNMISE LATIFAT(1), MUSTAPHA SHERIF ISHOLA(1), MOHAMMED ISHAQ ALHASSAN(1), SAKA HARVIS BAMIDELE(2), AJALA ELIJAH OLAWALE(1), OLUWASEYI SOILE SAMUEL(1)
Herein, the synthesis and characterization of a bentonite-supported Fe-Co-Ni trimetallic nanocatalyst applied in transesterification reaction was reported. The synthesized heterogeneous catalyst was used to investigate the production of biodiesel by varying the reaction parameters using Box-Behnken design response surface methodology (RSM-BBD). An optimum biodiesel yield of 95.2 % was obtained at methanol to oil ratio of 10:1, reaction time of 2 hours, reaction temperature of 55 ℃ and catalyst concentration of 5 % (w/w of the oil). The biodiesel produced was later analysed using GC-MS analysis and the results shows a fatty acid methyl esters (FAME) profile that confirms the presence of biodiesel.
ENVIRONMENTAL TEMPERATURE AND HUMIDITY MONITORING SYSTEM USING RASPBERRY PI 4 AND THINGSPEACK
DRAGOS-ALEXANDRU ANDRIOAIA(1*), GEORGE CULEA(1), PETRU-GABRIEL PUIU(1)
In recent years, IoT platforms have become increasingly used due to their untapped potential. This paper aims to create an IoT system to monitor temperature and humidity in an enclosure The Raspberry Pi 4 SBC (Single-Board Computer) development board and ThingSpeak cloud platform will be used to make this system. Data from the DHT11 humidity and temperature sensor will be collected by the Raspberry PI 4 SBC development board, which will transmit it via the WiFi connection to the IoT ThingSpeak platform cloud for further analysis. The IoT ThingSpeak platform provides data storage, processing and visualization services.
DIMETHYL N-CYANODITHIOIMINOCARBONATE AND TRIPHENYLPHOSPHINE OXIDE METAL HALIDE COMPLEXES: MOLECULAR CRYSTAL ELUCIDATION
MOUHAMADOU BIRAME DIOP(*1), MODOU SARR(1), SERIGNE CISSE(1), LIBASSE DIOP(1), ALLEN G. OLIVER(2), DAVID HUGHES(3)
Two MX2 (M = Ni, Zn; X = Cl, Br) dimethyl N-cyanodithioiminocarbonate compounds and one CrCl2 triphenylphosphine oxide complex were isolated and elucidated by single crystal X-ray crystallography. NiCl2[(CH3S)2C═NC≡N]2 (1) features inversion-related hydrogen bonded dimers linked into chains interacting through C-H···Cl growing layers along [110] whose junction into a 3D structure is enabled by H-bonds. ZnBr2[(CH3S)2C═NC≡N]2 (2) also exhibits inversion-related H-bonded dimers. In contrast with 1, the structure of 2 comprises chains along [110], connected via C-H···Br and C-H···S into a 2D layer along [-110]. CrCl2(OPPh3)2 (3) obtaining undergone redox processes, oxidizing [CH3C(O)CH2PPh3]+ to form PPh3PO, and reducing Cr from CrVI to CrII. In the structure, each molecule is linked to height neighbors through H-bonds affording a 3D network.
COMPARATIVE ANALYTICAL DETERMINATION OF THERMAL PROTECTION BEHAVIOR FOR EXPERIMENTAL MODELS MADE OF STRATIFIED BIOCOMPOSITE BOARDS OF LIGNO-CELLULOSE NATURE
SILVIA - ANDREEA NITU(1*), RADU I. IATAN(1), ION DURBACA(1), GABRIEL PETROSEL(1), ELENA SURDU(1), DANA CLAUDIA FARCAS - FLAMAROPOL(1)
The paper addresses the comparative analytical determination of thermal insulation behavior for various experimental models made of stratified and hybrid biocomposites of ligno-cellulose nature. The analytical determination of the thermal resistance and the overall thermal insulation coefficient for each experimental model is performed using the calculation methodology for energy efficiency. The results obtained after the analysis of the thermal insulation behavior for the biocomposite panels highlighted the fact that they have thermal insulation properties with high values for thermal resistance and global thermal insulation coefficients.
AN AUTOMATED SKIN DISEASE DIAGNOSTIC SYSTEM BASED ON DEEP LEARNING MODEL
LAWRENCE OMOTOSHO(1), KEHINDE SOTONWA(2), BENJAMIN ADEGOKE(3), OLUWASHINA OYENIRAN(4), JOSHUA OYENIYI(1*)
The use of computer technology has significantly advanced the medical sector, and many computer technologies have been used to develop healthcare, such as the patient management system, monitoring and control systems, and diagnostic systems. Technological advances in healthcare have also helped in saving numerous patients and are constantly improving our quality of life. Technology in the medical sector has also had a major effect on almost all healthcare professional techniques and practices. In order to facilitate rapid diagnosis and treatment of different skin diseases by the use of a deep learning model, this study developed a comprehensive framework to improve the decision-making of dermatologists in Nigeria in terms of the diagnosis of selected skin diseases. The developed system achieved the network accuracy of 98.44 % and the validation accuracy of the test set is 99.44 % as specified by the training results, further testing reveal that the developed system yielded rejection rate of 2.2 % and recognition accuracy of 97.8 %.
DESIGN ANALYSIS OF AN AUTOMATIC PHASE SELECTOR
ADEDOTUN O. OWOJORI(1*), ABIODUN M. AKINBOLADE(2), KAYODE F. AKINGBADE(1)
Power instability in Nigeria caused by overbearing demand of power by consumers and lack of proper maintenance of the power system devices among others has brought about the need for alternative power sources such as generators, solar, typical inverters and other alternative supplies which requires one form of switching or the other to achieve phase selection during power failure. This paper gives a design analysis of an automatic phase selector linking available power supplies, that is; switching between a three-phase public utility supply, as a result of total power outage in the public supply to an alternative secondary supply (in this case a Generator and an Inverter system) and back when power is restored. The design adopts the use of a microcontroller-based system interconnected with other hardware components for proper isolation, switching and visualization of switching conditions. The system design is divided into two major part: the hardware which consists of the power supply, sensing circuit, controller or control logic circuit, display and the power electronics switching unit and the software instruction code on the microcontroller unit. The design analysis was first carried out accompanied with computer simulation on a software tool (Proteus 8 Professional, version 8.4) to carry out performance evaluation of the sub-circuits, thereafter, a practical implementation of the design was carried out and tested with the utility power supply using five (5) switches, three of which represents the three-phase primary supply and the other two represents the secondary supply.
STABILITY CONTROL MODELLING UNDER DYNAMIC MOTION SCENARIO OF A DIFFERENTIAL DRIVE ROBOT
ADEDOTUN O. OWOJORI(1*), KAYODE F. AKINGBADE(1), WALIU O. APENA(1), ERASTUS O. OGUNTI(1)
Intelligence incorporated in many devices makes it easier to achieve self-balancing and autonomous driving in differential drive robot. Basically, differential drive robotic system describes an unstable, nonlinear system related to an inverted pendulum. The research attempts to harness the parameters obtained from a computer-aided design tool (Solid works) to model the system for complete stability control and dynamic motion of the system within a planned trajectory. A linearized dynamic equation is obtained for the overall system design of a mobile robot, and the linear quadratic regulator concept is adopted to obtain an optimum state feedback gain. The simulation results are obtained on MATLAB software interfaced with an Arduino board with deployable sensor technologies. Scenarios of disturbance would be simulated to ascertain the stability conditions of the system at static position or dynamic position. Signal analysis and computer vision techniques serve as leverage to make the design achievable. Localization and navigation referred to as tracking a planned trajectory or moving through paths filled with obstacles in a given space are also included.
ELECTRICITY METER WITH THE FACILITY TO DETERMINE THE QUALITY OF THE ELECTRICITY SUPPLIED
DAN ROTAR(1*), GEORGE CULEA(1)
Many areas of activity face the problem of electricity quality. At the same time, diagnosing the quality of the energy provided makes it possible to identify and remedy problems that have arisen in the system. Advanced signal processing techniques and the use of advanced systems allow for a complex analysis of the phenomenon. The paper presents an electricity meter equipped with an electricity quality analysis system. It was developed based on the Xilinx Artix-7 programmable logic matrix. A Digilent Arty A7 development board was used due to its design and experimentation facilities. The developed system determines the power consumed and the main elements that define the quality of electricity: harmonics and other deviations from the frequency of nominal power supply, flicker, voltage gaps, voltage variations, transient surge, temporary surge, etc. The possibility of using an embedded system equipped with the Microblaze soft microprocessor, the existence of a 12-bit analog-digital converter and the maximum sampling frequency of 1 MSPS and the possibility of assisted design allows to obtain a measurement system with superior characteristics. The results obtained and the experiments carried out confirm the expected performance for the electricity meter.
REDUCING THE ENERGY CONSUMPTION OF SYSTEMS WITH THE INTEGRATED CIRCUIT TI 430FR2433
DAN ROTAR(1*) , DRAGOS-ALEXANDRU ANDRIOAIA(1)
The Texas Instruments microcontrollers in the MSP 430 series offer four ways to save power in operation in such a way as to allow for consistent reduction of the electricity consumed. Code Composer Studio programming environment also provides support in making low-power applications. In addition to these, the MSP430FR2433 microcontroller with ferroelectric RAM allows data to be stored even in the absence of power voltage. In view of these properties of the microcontroller, a data logger application has been developed to monitor the quality of the environment in a building. Given that the MSP430FR2433 microcontroller can process both analog and numerical signals, the device monitors the temperature, humidity, carbon dioxide concentration and amount of light present in the enclosure. Thanks to energy-saving mechanisms and the possibility of keeping information for an indefinite period without the need for energy consumption, the ambient quality monitoring device can operate for a long time in places without energy resources. The device has also been tested with good results for autonomous operation using solar energy and has also been used to determine the energy performance of buildings.
ASPECTS REGARDING THE CUTTING CAPACITY OF DIAMOND DISCS USED IN THE FLAT GRINDING OF HARD GRANITE AND BASALT MINERAL MATERIALS
PETRE VALEA(1*)
The paper presents how to determine the partial and global cutting capacity (CC) based on technological evaluation criteria (sustainability, specific energy consumption, cutting forces, roughness) and technical economic criteria (grinding productivity and cost). The theoretical-experimental model that allows the determination of the global CC for diamond discs takes into account the specific features of these super abrasive tools and the cutting process for flat grinding of hard mineral materials granite and basalt. Also, are presented the characteristics of diamond discs, the experimental stand and the factorial plans used in the experimental part.