Advances in Material Science and Engineering

The design of the roof system has a significant impact on a building’s energy consumption, particularly in warmer climates with high cooling demands. In response to these challenges, a roof system reformation project was undertaken, incorporating various passive methods and a Ventilating Reflective Insulation System (VRIS) to enhance roof cooling practices. The passive techniques employed in the project included the use of a reflective finishing layer on the roof and a specially designed concrete slab. The concrete slab featured lightweight foam concrete and hollow cores, which contributed to its effectiveness in reducing heat transfer. This system facilitated the exchange of air between the roof and the external environment, helping to dissipate heat and maintain lower interior temperatures. Under an ambient temperature with a maximum of 39.8 ℃, the adoption of passive methods alone resulted in an average decrease of 7.31 ℃ in the roof interior temperature. On the other hand, the implementation of the VRIS contributed to an average roof interior temperature of 32.25 ℃. This represented a remarkable reduction in the average difference between the interior and ambient temperatures, shifting from 4.61 ℃ to -4.06 ℃ when compared to a conventional roof.

Artificial Neural Network (ANN) method is used to estimate femur bone for Malaysian adults’ population. The main objective of this study is to investigate the reliability of ANN to predict the length of femur for Malaysia adults. Currently computerized tomography (CT) scan and Magnetic Resonance Imaging (MRI) method were used to obtain multilayer images which the images converted to 3D image of bones for the measurements purposes. These methods are not safe which may harm hearing, claustrophobia and anxiety, peripheral muscle, and nerve stimulation due to the amount of radiation exposure during CT Scan or MRI. In addition, CT scans usually require more exposure to radiation than common x-rays because they use a series of x-ray images. Increased exposure means a slightly higher risk of possible short-term and long-term health effects. Therefore, as alternative method, ANN is chosen which as far as we concern, ANN is just a software based. However, to obtain the reliable ANN model, the measurements data are needed to train, validate and testing it. Thus, a total of 100 femur bones for normal Malaysian adults is taken from CT scan data to train, validate and test the ANN model. Based on the performance result, the ANN is capable of predict the measurement of femur bone with a high precision and accuracy since the percentage of errors are below than 5%. The purpose of this study holds the potential to serve as a valuable asset for the prediction of surgical outcomes and the analysis of risk factors for femur bone repair in Malaysia with minimal adverse effect to human body during bone measurements session.

In Malaysia, there have been various challenges faced by the logistics services companies throughout the years for businesses survival and new establishments. Logistics services consist of conveying by post through different types of transportation modes such as by land, sea, or air. This paper aims to present a research framework to assess and rank the performance of logistics services companies using Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) model based on the important financial ratios such as current ratio, return on assets, total assets turnover, debts-to-assets ratio and return on investment. In this study, GDEX, Hex Tech and Harbour-Link are ranked as the top three logistics services companies based on TOPSIS model.

As environmental temperatures continue to rise, one of the most pressing challenges we face is ensuring an adequate food supply to meet the needs of the growing human population. The impact of climate change extends to various factors including water scarcity in farmland, soil pollution, and numerous other aspects. The nation’s production for 26 vegetable crops had gone down 4% in the year 2021 compared to year 2020. In this context, hydroponics emerges as a promising agricultural method, offering a viable alternative solution to tackle these challenges. The paper presents an overview of hydroponic farming, encompassing its types, advantages, nutrient solution composition, factors such as Potential of Hydrogen (pH) value, Electrical Conductivity (EC) value, and water temperature. It is concluded by underscoring the significance of meticulous evaluation regarding the limitations of research outputs, particularly regarding the role of water temperature in hydroponics, as not highlighted among the journal papers. Furthermore, the paper proposes the necessity for additional research on vertical hydroponics systems to investigate the influence of water temperature on plant growth.

Stainless steel SS304 is commonly used in dental applications due to its greater properties, including high strength, hardness, and corrosion resistance. However, the challenge lies in finding eco-friendly methods for joining SS304 with powder-based metals. This study suggests using microwave hybrid heating (MHH) to join SS304 (15 mm × 7.9 mm × 0.2 mm) and pure tin powder (44 µm and 99% purity). Temperature variations (30 °C to 60 °C) and cold processing (0 °C to 10 °C) were employed to assess microhardness and microstructures. Temperature had a direct impact on microhardness, with higher temperatures leading to increased microhardness. Optimal microhardness (530 HV) was achieved at 60 °C during a 3-min heat treatment. Temperature increases improved microhardness at the joint interface, while cold processing caused slight deformation and grain changes. Heat temperature induced deformation, enhanced grain density and hardness at the fast-cooling rate, particularly at the strongly bonded boundary layer. Experimental and fuzzy logic-predicted values for the zinc joint exhibited promising results with errors below 10%.

This study investigates the hot forging process of S45C carbon steel, a commonly used alloy. The process involves heating the workpiece above its recrystallization point to enhance flexibility, followed by compressive deformation. The study compares the methodology for determining Zener-Hollomon parameters using experimental data analysis and default simulation software parameters. Compressive tests at strain rates of 0.1–10 s⁻¹ and temperatures 900–1200 °C are conducted. The results show that parameters obtained from compressive testing are significantly more accurate than default software parameters, with only a 2.87% error compared to the software default parameters errors, which is as high as 35.05% for the Preforming Process and 3.40% and 31.41% for the Finishing process. This underscores the importance of accurate material data in simulations for hot forging processes and offers valuable insights for improving precision, efficiency, and cost-effectiveness in hot forging operations.

The study deals with ambient air temperature effect on engine performance which work by spark and exhaust temperature with different parameters which effect on performance. The experiments included testing performance parameters and emissions for single cylinder SI engine at different conditions. The intake air temperatures was recorded from 15 ℃ to 75 ℃ with increase 10 ℃ at different speed engine conditions at 1500, 2000, and 2500 rpm. The results show that the increase of intake air temperature will improve fuel consumption and thermal efficiency about 14–16% approximately, and show reducing in volumetric efficiency with increasing of intake air temperature by increasing of sinking air temperature led to increasing of exhaust temperature.

Paraffin wax stores a large amount of latent heat during its transition from a solid to a liquid. The low thermal conductivity of paraffin limits the rate at which heat can be transferred. An attempt was made to address this problem by incorporating nanomaterials with high thermal conductivity nanoparticles into the Paraffin. Several concentrations of alumina (Al₂O₃) and iron oxide (Fe₂O₃) nanoparticles were added to the paraffin in mass fractions of 1, 2, and 3%. Iraqi Paraffin wax, as side product from the petroleum refining, has been used in this study. The results show that Paraffin’s thermal conductivity improved by 37.1%, 42.3%, and 60.32% when Al₂O₃ nanoparticles were added at 1%, 2%, and 3%, respectively; while same added percentage of nano-Fe₂O₃ led to thermal conductivity improvements of 29%, 34.16%, and 48.98%, respectively. It noticed that the Paraffin color was changed from light brown to white after nano-Al₂O₃ was added and to black after nano-Fe₂O₃ was added. There was a slight increase in the density and viscosity of the produced nanocomposites. When nano-Fe₂O₃ is added, the melting point and solidification point decrease by one 1.0 ℃ and by 1.0 to 1.5 ℃ when nano-Al₂O₃ is added. There was a decrease in the phase change period of the composite samples examined. Tests of stability over 300 melting-solidification cycles showed high stability. For the compound material to remain stable, it is recommended to repeat the mixing process annually.

The incorporation of nanofillers into polymer matrices has been in the limelight for its versatile capabilities as polymer nanocomposites in electrical applications. In this investigation, the dielectric constants of polylactic acid/polyhydroxyalkanoates biopolymer composite with aluminum nanofillers were evaluated. Employing standard fabrication and testing procedures, the highest dielectric constant was observed at PLA-PHA-Al at 15 vol % loading of nanofillers, which was exactly 5.5, denoting a high-k biopolymer composite fabrication. The experiment results were compared with a modified Paletto expression with consideration of mathematical formulae that conform with continuous nanoparticle dispersion and the presence of interphase regions that alter dipole moments within the composite. The Furukawa model for predicting dielectric constant was employed to modify the Paletto expression in terms of atomic and interphase distances of the nanofiller employed. The comparison that was made vividly describes the discrepancy between experimental and theoretical evaluations, whereby factors, such as impurities, and the formation of dipole moments between interphase regions could have affected the charge-storing capacity of the fabricated biopolymer composite.

In this study, a numerical technique is employed to predict the temperature distribution in the annulus. The cavity is formed using two cylindrical containers; the inner and outer radii of the aluminum heated rod are 5 and 11 cm, respectively, and the height is 30 cm. The annulus cavity is filled with three types of coolant: air, water, Al₂O₃, CuO, and ZrO₂ nanofluids with a volume fraction of 0.15 vol%. The results presented with the vorticity function, isothermal lines, and temperature contours of the annulus cavity were calculated by pretending to be in the 2-D axisymmetric domain. The results showed that using nanofluids of Al₂O₃, CuO, and ZrO₂ will decrease the temperature at the initial cooing process by about 9%, 12%, and 15%, respectively, as compared with using the air, and will decrease the temperature at the initial cooing process by about 3%, 6%, and 10%, respectively, as compared with using the water.

The thermal analysis study for condensation in wire on tube condenser depend on experimental data is done for vapor compression refrigeration system (refrigerator). The aim of this study is the comparing of the entropy generation during the condensation apply the exergy and the penalty factor analysis methods. Two methods consider the losses due to the heat transfer and the friction for the flow to find the total reduction in wire on tube condenser capacity and. The test done for R-134a and R-600a under the same cooling capacity required and same operation conditions. The results show the exergy method is more accurate than penalty factor due to the using of the second low efficiency in the analysis that is lead to select the lower power consumption refrigerant to operating the system.

Optical fibers are flexible cables made of glass or plastic that have a wide range of applications, including the new communication revolution, 5G. However, for light transmission from a source to another end use place, there are still some challenges, in particular the bending and transmission efficiency. This study aimed to study the concept of the manifestation of solar radiation for indoor lighting. To achieve the objective, an experimental investigation of optical fiber to transmit direct solar light to indoor space. The work consisted of experimental measurements and analysis of space lightning by optical fibers. The selected research variables are length of the optical fiber, 0.1, 0.2. 0.3, 0.4 and 0.5 m, and batch of optical fiber 10, 20, 30 and 40 units. In addition, the bending effect on the optical fiber capability is also tested. The tests were performed at various simulated solar light. It has been concluded that the increment of the optical fiber length and decrement of number of units per batch decreases the overall measured illuminance inside the lightened space. The light distribution was also studied, and it is validated that illuminance decreased as it’s further away from the source of the illuminance which is the end of the optical fiber itself. A bending test was conducted, and it is reasoned that bending doesn’t affect the illuminance of optical fiber in any way. The analysis done for optical fiber daylighting system suggests that it would be a possible alternative to the current electricity consuming indoor lighting system.