International Journal of Engineering and Applied Physic
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Characterization of mechanical properties of bamboo fiber-reinforced epoxy composites
Get PDFThis research investigates the mechanical properties of bamboo fiber-reinforced unidirectional epoxy composites, focusing on two bamboo species, Bambusa Vulgaris (Baijja bamboo) and Melocanna Baccifera (Mulli bamboo). The study examines the tensile, flexural, and impact properties of composites fabricated from bamboo fibers extracted from different sections (top, middle, bottom) of the bamboo culm. The composites were prepared using a hand layup method and subjected to mechanical testing according to ASTM standards. Results show that the middle portion of both bamboo species exhibits superior mechanical performance compared to the top and bottom portions. Specifically, the middle section demonstrates higher tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength. The enhanced properties of the middle section are attributed to factors such as fiber alignment, density, and composition. The findings suggest that utilizing bamboo fibers from the middle portion can lead to the development of high-quality composite materials suitable for various engineering applications, particularly in automotive part manufacturing. This research underscores the importance of understanding the mechanical behavior of bamboo composites for optimizing their use in sustainable and eco-friendly industrial products
Mode shapes for free vibration of clamped plates with various geometries based on an quadrilateral element
Get PDFThis work aims at presenting mode shapes for free vibration of clamped plates with various geometries based on a four-node quadrilateral element, CP-DSG4, related to discrete shear gap (DSG) strategy and adding a center point (CP). The efficiency of the CP-DSG4 element is demonstrated through some numerical tests
Nonlinear Evolution Equations : A Brief Review
Get PDFA brief review of nonlinear systems was undertaken including its brief history and an overview was given of some of the techniques used, like the Lax method and the AKNS method, to uncover solitary wave solutions and the specialized ones like the solitons
Assessment of occupational health and safety risks in selected construction sites in oyo state, Nigeria
Get PDFConstruction sites are an important part of the economy in many countries including Nigeria and is often seen as a tool for economic growth. However, these sites face significant occupational health and safety (OHS) challenges, characterized by high accident rates and substantial health risks. This study assessed occupational health and safety practices in selected construction sites in Oyo State, Nigeria, focusing on Reynolds Construction Company and Arab Contractors as case studies. Through a mixed-method approach involving interviews, questionnaires, and site observations, the research investigated current OHS assessment practices, risk management protocols, and implementation challenges. The study revealed critical findings: risk management responsibilities are exclusively delegated to contractors and limited to the construction phase, with no systematic assessment methodology in place. Instead, risk evaluation relies heavily on individual judgment, guided by personal experience, educational background, and existing regulations. The research identified that risk communication primarily occurs through toolbox meetings and informal discussions, while risk control predominantly depends on Personal Protective Equipment (PPE). Key factors influencing OHS management include regulatory frameworks, individual competencies, and work environment conditions. Notable challenges hampering effective OHS implementation include site configuration, procurement systems, design complexity, and geographical location constraints. Analysis of hazard consequences revealed that working at heights and manual handling presented the highest risk factors, followed by exposure to chemicals, dust, and noise. The study also found that 71% of workers lacked formal health and safety training, potentially contributing to the 31.74% rate of major accidents reported during task performance. This research recommends a more integrated approach to OHS management, emphasizing the need for active involvement from key project stakeholders, including clients, design teams, consultants, and government agencies, to enhance safety standards in Nigerian construction sites. The findings contribute to the understanding of OHS practices in developing countries and provide a framework for improving construction site safety in Nigeria. Therefore, in Nigeria, the study suggests that there is a need for the key project stakeholders such as client, design team consultants and government to be involved in managing health and safety risk on construction sites
Evaluation of production cost of bricks using clay and stone dust-cement
Get PDFThis study aimed to investigate whether mixing clay soil, stone dust, and 5% cement could enhance strength, reduce water absorption, and lower production costs, without compromising the material's quality. Clay soil from near FUTA, Akure and stone dust from a quarry were used. Tests were conducted on the raw materials, including sieve analysis, moisture content, bulk density, and specific gravity. Clay soil was partially replaced with stone dust at 0% (control), 5%, 10%, 15%, 20%, and 25%, with a constant 5% cement. 288 bricks were produced, 144 air-dried and 144 fired at 1000°C. Compressive strength and water absorption tests were performed on both burnt and unburnt bricks. The results showed that for burnt bricks at 28 days, water absorption ranged from 11.11% to 20.00%, and for unburnt bricks, 3.33% to 7.69%. The compressive strength of burnt bricks increased up to 15% stone dust replacement, then decreased, while unburnt bricks showed a gradual strength reduction with increasing replacement. Both results met NIS and BS standards for normal building bricks
On the Dynamics and Heat Transfer of a Conducting Droplet during Electrospraying in the Dripping Mode
Get PDFIn this study, the influence of an applied electric field on the hydrodynamic and heat transfer of a conducting liquid exiting from a nozzle in the dripping regime is investigated. The flow and energy equations along with the electrostatic equations are solved to simulate this problem. The sharp formulation of the level set technique is implemented to capture the interface accurately. Subjected to an electric field, the liquid is exited faster and its elongation before detachment of the droplet is increased. Also, after the first droplet detaches, the liquid returns towards the nozzle. The length of the exited liquid after returning towards the nozzle increases under an electric field. Therefore, under electric stresses, the droplet formation occurs faster due to the rapid exit and more elongation of the liquid. Also, the size of the formed droplet is reduced with electric field intensity. Under an electric field, the heat transfer rate enhances rapidly in a short time interval before droplet detachment. The total heat transferred to the liquid exited from the nozzle is reduced by increasing the electric field intensity
Stability analysis of double-diffusive convection in couple-stress Hall fluid
Get PDFThe aim of the present work was to study the effects of uniform horizontal magnetic field and Hall currents on the double-diffusive convection in couple-stress fluid through permeable media. Following the linearized stability theory, Boussinesq approximation and normal mode analysis, the dispersion relation is obtained. The stationary convection, stability of the system and oscillatory modes are discussed. For the case of stationary convection, the stable solute gradient and magnetic field postpones the onset of convection while the Hall currents hasten the onset of convection. The medium permeability and couple-stress both postpone and hasten the onset of convection depending on the Hall parameter M. The stable solute gradient and the magnetic field (and corresponding Hall currents) are found to introduce oscillatory modes in the system, which were non-existent in their absence. The sufficient conditions for the non-existence of overstability are also obtained
Complementarity of the trombe wall effect and air distribution in passive air conditioning of a single-zone building
Get PDFThe work in this article presents the study of the Complementarity of the trombe wall effect and the distribution of air to the passive air conditioning of a single-zone building by simulating the thermal behavior of a habitat located in Madagascar, in Antananarivo. The practical recommendation of the heat flow exchanged by thermocirculation is done in an ingenious system. The first part of the work will be based on the installation of a solar capture system, a vertical wall in heavy masonry facing north and equipped with two holes. It allows and facilitates the simulation of an air circulation system between this building and the greenhouse formed by the receiving surface of the wall and the glazing that precedes it. The second will develop the physical modeling of the system obtained by assembling simplified thermal models of the wall elements, glazing and air volume constituting this zone. The analysis of the system will be able to receive a well-air-conditioned home
Numerical solution of a viscoelastic contact problem with normal compliance and unilateral constraint
Get PDFA numerical method is presented for a mathematical model which describes the frictional contact between a viscoelastic body and an obstacle. The process is quasistatic and the material’s behavior is described by means of a viscoelastic constitutive law with long memory. The contact is modelled with normal compliance condition restricted by unilateral constraint, and associated to a version of Coulomb's law of dry friction. A solution algorithm is discussed and implemented. Finally, numerical simulation results are reported on a two-dimensional test problem. These simulations show the efficiency of the algorithm and the corresponding mechanical interpretations
The role of beam polarization on the quality of digital holograms
Get PDFHolography is an imaging technique that has attracted much attention since its inception due to its potential of recording three-dimensional images. As a result, the technique has been applied in fields like interferometry. However, its recording relied on the use of non-polarized sensitive materials which have been limited to the isotropic materials. In this study, we report the role of beam polarization on quality of holograms in respect to important parameters such as; the distance of the Charge Coupled Device from the object and variation of polarization angle. By varying the distance of the camera from the object, a distance of 15cm was clearly noticed to have produced holograms with a more comprehensive set of light wave characteristics; intensity, phase, and polarization state. We have also managed to record and reconstruct holograms at different polarization angles with significant impact on holograms at 0?, 15?, 30? and 45? whose amplitude and phase information was extracted at an optimum distance of 15cm. By comparing the results from these angles, holograms at 45? were of high quality. This advancement not only enhances the visibility of objects that are otherwise obscured or low contrast but also broadens the application of holography beyond isotropic materials