Algerian Journal of Engineering and Technology (AJET)
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Experimental study of ECG signal transmission system via a coaxial cable line using Duty-Cycle Modulation
No full textThis paper presents the first real and well tested prototyping duty cycle modulation (DCM) signal transmission system. The experimented system is applied to the transmission of ECG signals. It consists of an ECG signal acquisition system, a duty cycle modulation transmitter, a coaxial cable transmission medium and finally a simple low-pass filter as receiver. After a brief review of the literature highlighting the interest of this experiment, we analytically developed different parts of the proposed system. The experimental workbench and main results obtained are presented. These yield very good results since in addition to the high quality of ECG signal reconstitution, we manage to eliminate the power line interference induced during transmission. These results experimentally confirm the feasibility as well as new perspectives of using the proposed systems as a simple remote biomedical instrument.
 
Study and experimental prototyping of a digital instrument for detection and acquisition with local monitoring on LCD of ionizing radiations using BG51 module and ESP32 microchip
Get PDFThis paper presents a novel digital device for ionizing radiation detection in biomedical imaging media. It is designed and built using emerging technologies, in order to provide lower cost and high performance compared to existing biomedical instruments. The BG51 modular sensor is used as an ionizing radiation detector with corresponding pulses as output. Then, the ESP32 microchip acquires and digitalizes the ionizing radiation doses, and an associated 2.4-inch TFT LCD screen, is used as a hardware graphical monitor. A number of real time tests conducted in the laboratory, indicates that the ionizing radiation detection process, varies in the range [10µSv 2mSv]. In addition, the sample size with rate 30 samples per second, is approximately 25 000. Furthermore, the experimental results show the graph of ionizing radiation doses within a real environment where the proposed biomedical instrument is located.
 
Kinetic and thermodynamic studies of malachite green adsorption using activated carbon prepared from desert date seed shell
Get PDFThe negative effect of high concentration of dyes in the aquatic environment on humans and aquatic plants prompted this research. The adsorption of hazardous malachite green (MG) from aqueous solution using activated carbon derived from desert date seed shell (DDAC) was examined. Batch equilibrium technique was employed to study the effect of contact time (5-120 min), initial concentration (20-100 mg dm-3) and temperature (303.15-333.15 K) on the adsorption capacity of the prepared adsorbent. Experimental data were analyzed using five kinetic models: pseudo-first-order, pseudo-second-order, Elovich, intraparticle diffusion and Boyd models and it was found that the pseudo-second-order model fitted the adsorption data most with the highest correlation (R2 = 0.9999). The overall adsorption process appears to be jointly controlled by intraparticle diffusion and film diffusion mechanisms. Studies of thermodynamic behavior revealed negative values for ∆G (-11.45 to -13.42 kJ mol-1), and a positive value for ∆H (8.39 kJ mol-1) and ∆S (0.065 kJ mol-1 K-1). These indicated the feasibility, endothermicity and spontaneity of the removal process. The results demonstrated that the adsorbent could be exploited in the removal of MG from aqueous solution.
 
Combating chloride ions in reinforced concrete using K2Cr2O7 as corrosion inhibitor
Get PDFThe ingress of chloride ions from seawater in contact with concrete reinforced structures is one of the major causes of deterioration in the construction industries worldwide. This gives rise to corrosion of embedded steel in the concrete structures which sooner or later results in dilapidation, deterioration and partial or total failure of the reinforced structure. In this study potassium dichromate (K2Cr2O7) solution was used to mitigate the effects of chloride ions in reinforced concrete. Cylindrical concrete samples of size 15mm x 36mm diameter with cement to sand mix ratio of 1:6 and a water cement ratio of 0.5 were prepared. 12 mm high yield reinforcing bars were inserted into the sample. The samples were then immersed in NaCl solution with varying concentration of K2Cr2O7. Both weight loss method and linear polarization measurement were performed on the samples. Data acquisition and analysis were carried out using 4 decimal places electronic weighing balance, a potentiostat interfaced and a computer. The results from the weight loss method showed that the weight loss decreased from 0.7629g to 0.1398g for the 7th and 35th day respectively. Results from the potentiodynamic polarization method further revealed the efficiency of K2Cr2O7 in mitigating corrosion.
 
Synthesis and characterization of schiff base of 3-[(2-Hydroxy-phenylimino)-methyl]-6-methoxy-quinolin-2- ol and its metal complexes and their evaluation for antibacterial and antifungal activity
No full textA Schiff base of 3-[(2-Hydroxy-phenylimino)-methyl]-6-methoxy-quinolin-2-ol was synthesized by a 1:1 molar condensation of 2-Hydroxy-6-methoxy-3-quinolinecarboxaldehyde and 2-aminophenol. The metal (II) complexes were synthesized by refluxing the ethanolic solutions of the Schiff base and the chloride salts of the metals. Melting point, decomposition temperature, solubility, elemental analysis, fourier transform infrared spectroscopy, magnetic susceptibility and molar conductivity measurements were used to characterized the Schiff base and its metal complexes. The Schiff base is yellow and it has a melting point of 251 OC. The decomposition temperature of the Cd (II) and Cu (II) complexes were 282 and 270 OC respectively. The elemental analysis of the complexes established the formation of 1:1 metal - ligand ratio. The non-electrolytic natures of the complexes were revealed by the molar conductivity values. The behavior of the Schiff base and its coordination with the metal ions was suggested by the infrared spectral data via the azomethine nitrogen and hydroxyl oxygen after deprotonation. The solubility test of the Schiff base and its metal complexes were carried out by using different solvents. The antibacterial and antifungal activity were performed and discussed.
 
A conceptual framework for assessing the impact of human behaviour on water resource systems performance
No full textThe persistent poor performance of water resource systems (WRS) has been reportedly linked to not only climate change and dilapidated water infrastructures but also human unlawful activities. Some of these unlawful activities include unauthorized water abstractions, wastage, excessive losses, discharging untreated wastewater, over‐application of chemicals and fraudulent incidences. Despite advances in WRS planning and operational analysis, incorporating such undesirable activities to quantitatively assess their impact on WRS performance remain elusive. This study was then inspired by the need to develop a methodological framework for WRS performance assessment that integrated human impacts with WRS analysis tasks. A conceptual framework for assessing the impact of human behaviour on WRS performance using the concept of socio-hydrology is proposed herein. The framework identifies and coupled four major sources of water values (WRS, goals, managers and users) using three activities serving as the missing links between these values (interactions, outcomes and feedbacks). The framework can be used as a database for choosing relevant social and hydrological variables and to understand the inherent relations between the selected variables to study a specific human-water problem in the context of WRS management.
 
Experimental study of exfoliation corrosion-induced mechanical properties degradation of Aluminum alloys: 2024-T3 and 5083-H22
No full textThe objective of the present work were to study the influence of exfoliation corrosion (EFC) of 2024 and 5083 aluminum alloys on the mechanical properties degradation. Tensile test had been carried out on pre-corroded specimens, exposed to laboratory accelerated exfoliation corrosion solution. The analysis suggests that exfoliation exposure leads to decrease the mechanical properties of all materials. The effects of the grain boundary character distribution and precipitates on corrosion are discussed on the basis of experimental observations by Scanning Electron Microscope SEM combined with Energy Dispersive Spectroscopy EDS analysis.
 
An overview on use of renewable solar energy in desiccant based thermal cooling systems
No full textThe use of thermal energy produced by renewable solar heat is an interesting option for desiccant regeneration in comfort space cooling system. Various options available for collecting the solar radiations to provide reactivation heat for desiccant regeneration in desiccant assisted dehumidification and cooling system. This means of thermal cooling is economically viable as well as environment friendly. The integration of different solar collectors with the desiccant cooling cycle is resulted to the green cooling as it eliminates the use of CFC based ozone depleting refrigerants and CO2 as green house gases which is responsible for global warming. An overview is presented to introduce different configurations of the combined system and performance evaluation of the same under different climatic situations.
 
A compact multi band microstrip antenna
No full textThis paper presents the design of microstrip antennas for L, S and C band applications. The rectangular microstrip patch antennas are designed at a frequency of 2GHz and have been simulated using Mentor Graphics IE3D simulation software. The substrate used in the design is FR-4 glass epoxy which has a dielectric constant of 4.2. The operating frequency range is 1-7 GHz. The modified microstrip antenna with plus shaped slot at the centre of the patch yields an overall bandwidth of 10.47 % and lowest resonant frequency of 1.71 GHz. This antenna provides the size reduction of 13.63 %.
 
Environmental Nano-remediation in Nigeria: A Review of its potentials
No full textPollution of the environment is one of the most pressing problems confronting developing nations such as Nigeria and the world at large. Due to the unchecked quest for infrastructural and technological development, we have continuously explored and exploited our natural resources, paying little or no attention to the impact of these exploitations on our ecological environment. This negligence has resulted in some severe environmental degradation and the conventional methods previously employed in addressing these issues are no longer efficient, thus there is need for novel, innovative, advanced and efficient environmental remediation alternatives. Nanotechnology offers such alternatives and although most countries are embracing the idea, Nigeria is yet to fully explore this alternative. This paper seeks to throw more light on the application of nanotechnology as viable technique in remediating polluted soil and marine environment in Nigeria.