Algerian Journal of Engineering and Technology

Prediction of Compressive Strength of Concrete incorporating fine recycled aggregate using regression analysis

2024-10-29T08:41:16+00:00

The practical use of recycled aggregate produced from crushing concrete waste in the production of new concrete reduces the consumption of natural aggregate and also reduces the amount of concrete waste that ends up in landfills. This study addresses the properties of concrete containing recycled fine aggregate (RFA) obtained from existing waste in Mosul. Four sets of concrete mixtures with different compressive strength (25, 30, 35 and 40MPa) were prepared, and for each strength, the effect of changing the replacement ratios of natural fine aggregate with recycled fine aggregate was studied, where four different ratios (0, 10, 20, 30) % of recycled fine aggregate (RFA) were adopted. The focus was on the compressive strength of concrete containing recycled fine aggregate due to the importance of this property as an indicator of concrete feature and the main determinant of its quality and the most important factor in design. The results showed a gradual decrease in the fresh properties of concrete containing recycled fine aggregate, such as slump and fresh density, as the proportion of recycled aggregate increased. However, there was an improvement in the compressive strength of the concrete mixes. Based on the practical results, equations were derived to predict the compressive strength of concrete containing recycled fine aggregate. According to the theoretical results obtained through analysis of variance (ANOVA), it was found that adding recycled fine aggregate at a rate of 20% is considered the best proportion, although the change in compressive strength is not significant.

Neutron irradiation effect on dielectic loss of bi-stretched polyethylene naphthalate

2024-10-30T19:09:47+00:00

In the present work, the study of the evolution of the β^∗ process in both pristine and neutron irradiated bi-stretched polyethylene naphthalate films, is realized at a constant temperature and in the frequencies domain comprised between 10² and 10⁶ Hz by using the impedance spectroscopy technique. The results show the presence of dielectric loss peak determined in 10⁵ to 10⁶Hz frequency range, where the shape, position and the intensity are affected by morphological damage due to the large quantity of neutron beam energy transferred to the polymeric molecules that were highlighted by different structural analysis such as the Fourier transform infrared spectroscopy (FTIR) and the polarized light optical microscopy (PLOM). At room temperature, the FTIR technique showed an increase in the quantity of the carbonyl and naphthalene groups responsible of the presence of the Sub-Tg dielectric relaxation in the volume of the irradiated BSPEN (IR-BSPEN) film due to the amorphization phenomena traduced, respectively, by the absence and presence of the absorption bands characteristics of crystalline and amorphous phases. The PLOM characterization, revealed change in the texture of the IR-BSPEN surface indicating by the appearance of microcracks which contribute to the oxidation of macromolecular chains. The study of the effect of temperature on the dielectric behavior of non irradiated BSPEN film, in β^∗ region, showed that the dielectric parameters such as the maximum of dielectric losses and its position are thermally activated. This dielectric response has not identified in the case of irradiated BSPEN film, for which the evolution of losses with temperature change above T = 333K.

Neutron defect emulation using ion beam in zircaloy-4

2024-11-18T19:11:56+00:00

The present study is devoted to study ion beam induced defects in zircaloy-4. We focused on the effect on the surface morphology modifications. The samples are first polished and then bombarded with 20 MeV Au ion and 0.7 MeV Cu ion at room temperature to a dose of 4.5 dpa. After irradiation the samples were subjected to chemical etching in 47 ml nitric acid (HNO₃), 3 ml hydrofluoric acid (HF) and 50 ml water (H₂O). Optical microscopy observation showed drastic changes in the microstructure after irradiation. The observation at the interface between the irradiated part and non-irradiated part revealed a clear shrinkage parallel to the ion beam direction. Fine grain of about 10 µm diameter are formed on the surface of zircaloy-4 irradiated at low energy (S_n/S_e << 1) while a hillocks-like nanostructure is observed in the case of high energy irradiation (S_n/S_e >> 1). Both cases can affect the zircaloy-4 corrosion resistance.

Simulation and Analysis of I(V) and P(V) Characteristics of a Photovoltaic module under MATLAB/SIMULINK Connected to the Electrical Grid

2024-11-02T09:29:01+00:00

The objective of our work is the simulation and analysis of the I(V) and P(V) characteristics of a photovoltaic module under MATLAB/SIMULINK connected to the electrical network. To achieve this goal, we followed the following steps: At the start of work; we performed a simulation of a photovoltaic cell (photovoltaic module). By two methods: by simulation of the mathematical data of the model of a photovoltaic module inspired by the electrical diagram of a photovoltaic cell, by the use of the mathematical equations of: inverse saturation current, saturation current, photonic current, current of the shunt resistance, and the output current to create from each equation a model in MATLAB/SIMULINK, then we collect and connect these models according to the mathematical equation to obtain the final model of the output current of a photovoltaic module, and on the other hand by simulation through the model of the solar cell which exists in the SIMULINK library by checking the data of each box coming from this source. then we showed the Simulation of the BOOST converter with MPPT, and we presented the functional diagram of the PV generator and the BOOST converter with MPPT under MATLAB/SIMULINK, In the same context, we showed the voltage curve at the output of the command MMPT in MATLAB, the current curve at the output of the chopper booster, the curve of the voltage measured at the converter, the curve of the current measured at the converter, the curves of the phase currents of the network and the reference current, and the curve of PV generator power and Pmpp power At the end of the work, we connected this photovoltaic module to an electrical network, to see the impact of our network on the photovoltaic module and vice versa. Finally we explained and interpreted the results obtained according to our points of view.

Proposal for a standardized backplane interface board to support the development of future Algerian CubeSats

2024-11-18T21:15:48+00:00

The CubeSat standard provides access to space industries without the need to manufacture complex satellites requiring specific and costly resources. This type of satellite has proven its ability to accomplish several missions, namely, the demonstration of technology, scientific research, and even commercial missions. While various internal architectures exist for CubeSats, including PC104 and backplane configurations, the backplane approach offers superior modularity and simplicity. This makes it particularly suitable for collaborative development between organizations, especially universities. This paper proposes a standardized backplane architecture for future Algerian CubeSats, presenting both an internal configuration and a preliminary design for a backplane interface board. The proposed design enhances modularity, streamlines integration procedures, and provides a scalable foundation for Algeria's emerging CubeSat program. By establishing this standard, we aim to facilitate knowledge sharing and collaborative development within Algeria's space technology sector.

Performance of ISIAMOD and SWAP models in estimating Soil water balance components of a maize crop (Sammaz-28) under Rain-Fed condition

2025-01-08T20:13:42+00:00

In this paper, the performance of Irrigation Scheduling Impact Assessment model (ISIAMOD) and Soil-Water-Atmosphere-Plant (SWAP) relationship model in estimating soil water balance of a cropped field under rainfall condition was studied under a sandy clayed loamy soil at the research field of the department of Agricultural Engineering, Ahmadu Bello University, Samaru, Zaria-Nigeria. Soil water balance data from the field study were used as reference values for the models performance evaluations. The statistical indicators used to compare the performance of the models were coefficient of residual mass (CRM), modelling efficiency (EF) and root mean square error (RMSE). The results showed that the two models satisfactorily simulated soil water balance components as their output compared closely to field measured data. CRM showed that ISIAMOD has the tendency of underestimating the ET, T, and E_cropby a value which ranges from 2.5 to 6.0 % while SWAP has the tendency of overestimating the same components which ranges from 2.0 to 9 %. The modeling efficiencies of the two models range from 84 to 90 %, except for evaporation processes which ranges from 54 to 62 %. The RMSE of the two models ranges from 0.29 to 0.86. They both simulated the seasonal run-off and drainage well. The results show that the two models can be used for determination of soil water balance components of cropped soil and for analyzing a better water management option for agricultural production.

Design and fabrication of an angle of repose apparatus for granular material analysis

2025-01-06T19:13:31+00:00

The angle of repose (AOR) plays a crucial role in analyzing the flowability of granular materials, which are widely used in fields such as agriculture, pharmaceuticals, and civil engineering. This study outlines designing and constructing an affordable, user-friendly Apparatus for accurate AOR measurement. Built for both laboratory and field applications, the Apparatus was made from materials that are easily accessible and include an adjustable funnel, a central column, and a sturdy base to ensure consistent and precise measurements. Experimental tests using agricultural materials such as rice, beans, wheat, and millet yielded reliable results with low standard deviations. A paired t-test indicated significant statistical differences between the newly designed Apparatus and conventional methods (t-statistic of -2.98, p-value of 0.015), though these differences fell within an acceptable experimental range of ±0.5°. The mean difference of -0.26° and a 95% confidence interval of [-0.43°, -0.09°] illustrate a slight downward bias in the Apparatus while confirming its reliability and accuracy. This research provides a practical solution for measuring AOR, especially in resource-constrained environments, and suggests potential enhancements, like incorporating digital sensors for greater precision and changeable orifice opening sizes for the funnel ranging from 10 mm to 22 mm.

Development and characterization of novel fast nanosized scintillator Y2SiO5: Ce3+ prepared by polymer-assisted Sol–Gel method for radiation detection applications

2025-01-10T20:19:10+00:00

In this study, three sample detectors were meticulously crafted using cerium-activated X₁-Y₂SiO₅: Ce³⁺ powder prepared via the monomer and polymer-assisted sol–gel method. The investigation aimed to assess how ethylene glycol (EG) monomer, polyethylene glycol (PEG) polymer, and polyvinyl alcohol (PVA) polymer influence the Coincidence Timing Resolution (CTR) of Ce³⁺ (xCe = 0.01)-doped Y₂SiO₅, with the goal to enhance radiation detection technologies. An advanced nuclear instrumentation system was set up to measure the coincidence timing resolution using 511 keV annihilation photons emitted by a ²²Na radioactive source. Results showed that complexing agents significantly affected the CTR of YSO: Ce³⁺ nanoscintillators, with the EG-prepared sample detector exhibiting the most favorable CTR of 480±21 ps. These findings enhance our understanding of YSO: Ce³⁺ nanoscintillators’ synthesis and optimization, underscoring the pivotal role of the chemical environment and emphasizing the superior performance of ethylene glycol. These insights provide valuable avenues for further advancements in radiation detection and medical imaging applications.

Effect of Guinea Corn Husk Ash (GCHA) on the compressive strength and water absorption of mortar

2025-01-12T12:27:10+00:00

In this research work, the weight loss, compressive strength, and water absorption of samples of cured mortar are measured to assess the effects of adding a 2% increment of GCHA content into the mortar mixture as a partial replacement of cement to determine how this addition affects the strength and other physical properties of the mortar samples produced. Compressive strength, slump, and water absorption tests were conducted according to BS EN 12390-3 (2009), BS EN 12350-2 (2009), and BS 1881-122 (2011) respectively. The results show that adding GCHA into mortar mix improves the mortar's strength up to 4% replacement level before it starts to decline. Moreover, adding more GCHA to mortar increases the mortar slump and water absorbance while density decreases. In addition, the study also reveals that GCHA-containing mortar is easier to handle than the control sample. These findings collectively support the potential of incorporating agricultural waste material in construction practices to achieve environmentally sustainable and durable building materials.