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In recent years, bamboo seems to have attracted the attention of researchers due to its advantages over synthetic polymers including being renewable, environmentally friendly, and fully biodegradable. Bamboo fibers at (9, 13, and 18 wt%) are filled with epoxy resin and the effects of mixing the bamboo fibers on mechanical properties were studied. In this paper, the tensile properties and performance of natural bamboo fiber powder-reinforced epoxy polymer matrix-based composites were investigated at three different curing temperatures ranging from T26 °C, T38 °C, and T50 °C. The results showed that the tensile strength and Young's modulus of the bamboo fiber/epoxy composites increased at T26 °C are 41.6 MPa and 2.84 GPa, respectively, for particle size 0.52 μm at a weight loading of 13 %. The increase in tensile strength is due to the excellent fiber matrix interface adhesion. However, it was found that the samples tested under T26 °C for bamboo fiber-reinforced epoxy composites acquired better tensile strength than those tested under the high temperatures of T38 °C and T50 °C. According to the analysis of the flexural characteristics of bamboo particle/epoxy composites, the composite with 1.5 μm particle size has the highest flexural strength at 13 wt% weight loading, measuring 105 MPa. The composite with a 1.5 μm particle size at 18 wt% loading records the maximum impact strength of, 5593 J/m2. This work provides a new approach for the development of lightweight and high-strength composite from natural fiber and polymer.

This study investigates the effects of epoxy coating and heat treatment on the surface wettability of Gigantochloa scortechinii bamboo in marine environments with varying seawater salinity. Bamboo strips were heat-treated at 160ºC, 170ºC, and 180ºC, followed by single and double layers of epoxy coating. Analyses of chemical changes and microstructures were performed using ATR-FTIR and FESEM. Surface wettability was evaluated through contact angle measurements. The results showed a reduction in bamboo hydrophilicity at 180ºC, as well as smoother surfaces and altered chemical compositions in treated specimens. Double-layer epoxy coatings provided better surface protection against water exposure. Increased hydrophobicity was observed with higher treatment temperatures, particularly at 180ºC. Additionally, bamboo surfaces in 100% saline solutions demonstrated higher wettability compared to 50% and 0% salinity levels. These findings indicate that the combination of 180ºC heat treatment and double-layer epoxy coating enhances bamboo’s hydrophobicity, making it more suitable for marine applications.

Current investigation aims to introduce and analyze an oblique-finned corrugated to evaluate numerically an unique method for improving heat transfer. Vertical gap ratios (V) of 0.15, 0.20, and 0.25; horizontal gap ratios (H) of 0.03, 0.04, and 0.05 as well as oblique-angle (θ) values of 10°, 20°, and 40° are just a few of the design factors that are examined. The targeted channels are subjected to turbulent air flows that are simulated using the finite volume technique (FVM) and the κ-ε model under constant temperature circumstances (T = 300 K). The data show that the novel approach enhances fluid mixing, which enhances heat transfer and, ultimately, thermal-hydraulic performance (PEC). The outcomes also show that frictional loss was employed to stimulate the target system's overall performance in the way of reducing the impact of heat transfer. Additionally, the findings uncover that, in comparison to other gap ratios, a moderate vertical gap ratio and a large horizontal gap ratio have a greater impact on heat transfer rate and PEC, respectively. Accordingly, the Nusselt number enhances by 73 %, 74 %, and 72 % across the same range of Reynolds number at a group of gap ratios (V = 0.15, h = 0.04), (V = 0.2, h = 0.05), and (V = 0.25, h = 0.05), respectively. Besides, the design parameters V = 0.2, H = 0.05, andθ = 40° yielded the best PEC of 2.547. New correlations for the innovative oblique-finned corrugated model are also presented.

New oblique fins with corrugated edges to incorporate into the rectangular channel have been suggested in current work to boost heat transfer. Current investigation aims to introduce and analyze an oblique-finned corrugated (OCF) to numerically evaluate a unique method for improving heat transfer. Vertical gap ratios (V) of 0.15, 0.20, and 0.25; horizontal gap ratios (H) of 0.03, 0.04, and 0.05; and oblique-angle (θ) values of 10°, 20°, and 40° are just a few of the design factors that are examined. The results show that the Nusselt number enhances by 73.5%, 74%, and 73.2% across the same range of Reynolds number at a group of gap ratios (V = 0.15, h = 0.04), (V = 0.2, h = 0.05), and (V = 0.25, h = 0.05), respectively. Besides, the design parameters V = 0.15, H = 0.05, and θ = 40° yielded the best PEC of 2.437. New correlations for the innovative oblique-finned corrugated model are also presented.

This paper investigates the heat transfer performance of different nanofluid coolants with the employment of a single nozzle, axisymmetric, and confined jet impingement method. A numerical analysis using Ansys FLUENT software is carried out. A mixture of hybrid nanoparticles in a fluid further increases the heat transfer performance. The type of coolants used in this study is pure water as the base fluid, Al2O3-Cu/water hybrid nanofluid, and two types of single-particle nanofluids which are alumina, and copper nanofluids. Although the study of hybrid nanofluid as a coolant has become more prominent among researchers, a specific trend of the efficiency and performance of different coolants used in the jet impingement method is still not widely available. The results from this study showed that in comparison with water as the base fluid, there is an increase in the average heat transfer coefficient of the target surface of about 8.73% for hybrid nanofluid, 1.89% for Al2O3 nanofluid, and 0.17% Cu nanofluid. Hybrid nanofluid shows the highest heat transfer performance and reduces the greatest amount of heat from the surface to the fluid.

Gigantochloa scortechinii is one of the most well-known bamboo species in Malaysia because of its advantageous physical, morphological and strength properties. This study presented the effect of alkali treatment conditions of single cellulosic bamboo strips fiber following tensile test and optimized the parameters through response surface methodology based on central composite design. Bamboo strips fiber was treated under various alkali concentrations of 2, 4, 6 and 8 wt.% and soaking times of 1, 3, 6, 12, 18 and 24 h. Results showed that the optimum tensile strength at 4 wt.% alkali concentration and 12 h soaking time was improved by 28% compared with water retting condition. The design-Expert software was used to optimize the tensile properties of single cellulosic bamboo strips fiber. The effect of two independent variables, namely, alkali concentration and soaking time, on the optimized tensile properties of a single cellulosic bamboo strips fiber was investigated. Results showed acceptable R2 and high R2Adj correlation coefficients for tensile strength, reaching 0.6926 and 0.9575, respectively. The high R2 and R2Adj correlation coefficients for tensile modulus reached 0.9376 and 0.8931, respectively. Overall results showed that the confirmatory experiments show that the error between predicted and actual values does not exceed 5%. thus, the model can be effectively used to predict tensile properties.

Electric vehicle (EV) is advancing as the transportation industry and the demand is expanding globally. The use of liquid cold plate (LCP) in EV battery is more effective in providing the desire temperature rather than using the conventional air cooling. The use of straight fins is being switched to oblique-shape fins to assist disruption of the thermal boundary layer development. The arrangement of fins in the LCP also will affect the performance of it cooling the battery. Three different arrangement of the oblique fin are developed to enhance the fluid flow and heat transfer performance. The LCP contains three arrangements of oblique fin namely as inline, incline and loureved. Experimental and numerical results reveal the good aggrement where the Nusselt number is enhanced with the louvered arrangement. Among three arrangements, loureved obtained the lowest surface temperature of the battery followed by inline and incline. It also found that Nusselt number increases as the Reynolds number increases. The LCP is able to maintain the average surface temperature of the battery below permitted working temperature of 50 °C. This shows that the present LCP with oblique fin could be a promising method for EV battery thermal management. Keywords: Liquid cold plate, Oblique fin, Heat transfer, Electric vehicle

Wind flow through urban areas is studied either by wind tunnel scale experiments or via computational fluid dynamics simulations through full-scale actual models. The large difference between the Reynolds numbers based on the geometries of actual cities and wind tunnel scale cities makes the dynamic similarity between the two models uncertain. In this study, the mean and turbulent flow parameters were investigated using a large eddy simulation for two models i.e. the actual urban area model and the wind tunnel scale (1:1000) model. Kuala Lumpur City Centre, Malaysia, was considered as the case study of an urban area. Vertical velocity profiles were plotted at five locations representing different building packing densities. The results of wind tunnel scale model largely agreed with the actual model with some discrepancies in the building vicinity and wakes. The dissimilarity of the wake patterns due to the large difference in Re was responsible for the deviations. Largest discrepancies were found in the lateral and wall-normal velocity components and turbulence stresses. The results casted a shadow on the applicability of the conclusions derived from the simulations on wind tunnel scale models to the actual urban environments they represented. The deviation between the two models should be assessed before proceeding with experimental or numerical simulations on small-sized models.

As the automotive industry progresses, electric vehicles (EV) grow with increasing demand throughout the world. Nickel-metal hydride (NiMH) battery and lithium-ion (Li-ion) are widely used in EV due to their advantages such as impressive energy density, good power density, and low self-discharge. However, the batteries must be operated within their optimum range for safety and good thermal management to enable a longer lifespan, lower costs, and improve safety for EV batteries. The need for a liquid cold plate (LCP) to be used in EV batteries is now highly reliable on the distribution of the required temperature rather than only standard cooling systems. The fins arrangement in the LCP would likewise impact the cooling efficiency of the EV battery. The main objective of this paper is to determine the heat transfer enhancement of liquid cold plate systems with the oblique fin and different types of liquid coolants. In the experimental test, two liquid types are used namely G13 ethylene glycol and distilled water in five steps, 10% ethylene glycol, 100% distilled water, 75% ethylene glycol + 25% distilled water, 50% ethylene glycol + 50% distilled water, and 25% ethylene glycol + 75% distilled water. Three different flow rates have been utilized which are 0.3, 0.5, and 0.7 GPM to maximize the productivity of flowing fluid and heat transferring with the gate door valve. The LCP encompasses the inline configuration of the oblique fin, which is able to enhance the heat transfer rate from the heater to the liquid cold plate. A GPM of 0.7 reached the least surface temperature for the battery in the three different flow levels. The LCP is capable of sustaining the ambient surface temperatures of the batteries just under the permissible 50 °C operating temperature, which indicates that the developed LCP with the oblique fin may perhaps become an effective option for the thermal control of EV batteries.

Over the years, the world was not paying strict attention to the impact of rapid growth in plastic use. This has led to unprecedented amounts of mixed types of plastic waste entering the environment unmanaged. Packaging plastics account for half of the global total plastic waste. This paper seeks to give an overview of the use, disposal, and regulation of food packaging plastics. Demand for food packaging is on the rise as a result of increasing global demand for food due to population growth. Most of the food packaging are used on-the-go and are single use plastics that are disposed of within a short space of time. The bulk of this plastic waste has found its way into the environment contaminating land, water and the food chain. The food industry is encouraged to reduce, reuse and recycle packaging materials. A wholistic approach to waste management will need to involve all stakeholders working to achieve a circular economy. A robust approach to prevent pollution today rather than handling the waste in the future should be adopted especially in Africa where there is high population growth.

Impinging jets are considered to be a well-known technique that offers high local heat transfer rates. No correlation could be established in the literature between the significant parameters and the Nusselt number, and investigation of the interactions between the correlated factors has not been conducted before. An experimental analysis based on the twin impingement jet mechanism was achieved to study the heat transfer rate pertaining to the surface plate. In the current paper, four influential parameters were studied: the spacing between nozzles, velocity, concentration of Nano solution coating and nozzle-plate distance, which are considered to be effective parameters for the thermal conductivity and the heat transfer coefficient of TiO2 nanoparticle, an X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) analysis were done, which highlighted the structure and showed that the nanosolution coated the surface homogenously. Moreover, a comparison was done for the experimental results with that of the predicted responses generated by the Design Expert software, Version 7 User’s Guide, USA. A response surface methodology (RSM) was employed to improve a mathematical model by accounting for a D-optimal design. In addition, the analysis of variance (ANOVA) was employed for testing the significance of the models. The maximum Nu of 91.47, where H = S = 1 cm; Reynolds number of 17,000, and TiO2 nanoparticle concentration of 0.5% M. The highest improvement rate in Nusselt was about 26%, achieved with TiO2 Nanoparticle, when S = 3 cm, H = 6 cm and TiO2 nanoparticle = 0.5 M. Furthermore, based on the statistical analysis, the expected values were found to be in satisfactory agreement with that of the empirical data, which was conducted by accounting for the proposed models’ excellent predictability. Multivariate approaches are very useful for researchers, as well as for applications in industrial processes, as they lead to increased efficiency and reduced costs, so the presented results of this work could encourage the overall uses of multivariate methods in these fields. Hypotheses: A comparison was done for the predicted responses generated by the Design Expert software with the experimental results and then studied to verify the following hypotheses: ► Preparation of three concentrations of TiO2 nanosolution was done and studied. ► The heat transfer rate could be increased by surface coating with TiO2 nanoparticle. ► The heat transfer could be improved by the impingement jet technique with suitable adjustments.

Plastics have remained the material of choice, and after serving their intended purpose, a large proportion ends up in the environment where they persist for centuries. The packaging industry is the largest and growing consumer of synthetic plastics derived from fossil fuels. Food packaging plastics account for the bulk of plastic waste that are polluting the environment. Additionally, given the fact that petroleum reserves are finite and facing depletion, there is a need for the development of alternative materials that can serve the same purpose as conventional plastics. This paper reviews the function of packaging materials and highlights the future potential of the adoption of green materials. Biopolymers have emerged as promising green materials although they still have very low market uptake. Polylactic acid (PLA) has emerged as the most favoured bioplastic. However, it is limited by its high cost and some performance drawbacks. Blending with agricultural waste and natural fillers can result in green composites at low cost, low greenhouse gas emissions, and with improved performance for food packaging applications. The continent of Africa is proposed as a rich source of fibres and fillers that can be sustainably exploited to fabricate green composites in a bid to achieve a circular economy.

This paper discusses the behaviour of different thermophysical properties of CuO water-based nanofluids, including the thermal and hydraulic performance and pumping power. Different experimental and theoretical studies that investigated each property of CuO/water in terms of thermal and fluid mechanics are reviewed. Classical theories cannot describe the thermal conductivity and viscosity. The concentration, material, and size of nanoparticles have important roles in the heat transfer coefficient of CuO/water nanofluids. Thermal conductivity increases with large particle size, whereas viscosity increases with small particle size. The Nusselt number depends on the flow rate and volume fraction of nanoparticles. The causes for these behaviour are discussed. The magnitude of heat transfer rate is influenced by the use of CuO/water nanofluids. The use of CuO/water nanofluids has many issues and challenges that need to be classified through additional studies.

The study systematically explored the effect of alkali concentration and soaking time on the microstructure and tensile properties of single-cellulosic Buluh Semantan. Scanning electron microscopy and tensile tests were conducted to determine the effects of different alkali treatments on the properties of the single-cellulosic bamboo fibers. In particular, the effects of NaOH concentration and soaking time on the tensile properties of the single-cellulosic bamboo fiber were investigated. The single-cellulosic bamboo fiber was immersed in 2, 4, 6, and 8 wt.% aqueous NaOH solutions for soaking times of 1, 3, 6, 12, 18, and 24 h. The tensile properties of the fiber increased after each alkali treatment. The alkali concentration and soaking time significantly affected the fiber properties. The ultimate tensile strength of the single-cellulosic Buluh Semantan treated with 2 wt.% NaOH for 12 h decreased to 214 MPa relative to the fibers that experienced water retting. The highest tensile strength herein was 356.8 MPa for the single-cellulosic fiber that was soaked for 12 h in 4 wt.% NaOH. Comparatively, the tensile strength of the single-cellulosic bamboo fiber that was soaked for 12 h in 8 wt.% NaOH was 234.8 MPa. The tensile modulus of the single-cellulosic fiber was 12.06 GPa after soaking in 8 wt.% NaOH for 18 h, indicating that a strong alkali treatment negatively affected the stiffness and suitability for use of the fibers in applications. The topography of the fiber surface became much rougher after the alkali treatments due to the removal of hemicellulose and other surface impurities. The alkali treatments substantially changed the morphology of the fiber surface, suggesting an increase in wettability.

Here, the researchers carried out an experimental analysis of the effect of the TiO2 nanosolution concentration on the heat transfer of the twin jet impingement on an aluminum plate surface. We used three different heat transfer enhancement processes. We considered the TiO2 nanosolution coat, aluminum plate heat sink, and a twin jet impingement system. We also analyzed several other parameters like the nozzle spacing, nanosolution concentration, and the nozzle-to-plate distance and noted if these parameters could increase the heat transfer rate of the twin jet impingement system on a hot aluminum surface. The researchers prepared different nanosolutions, which consisted of varying concentrations, and coated them on the metal surface. Thereafter, we carried out an X-ray diffraction (XRD) and a Field Emission Scanning Electron Microscopy (FESEM) analysis for determining the structure and the homogeneous surface coating of the nanosolutions. This article also studied the different positions of the twin jets for determining the maximal Nusselt number (Nu). The researchers analyzed all the results and noted that the flow structure of the twin impingement jets at the interference zone was the major issue affecting the increase in the heat transfer rate. The combined influence of the spacing and nanoparticle concentration affected the flow structure, and therefore the heat transfer properties, wherein the Reynolds number (1% by volume concentration) maximally affected the Nusselt number. This improved the performance of various industrial and engineering applications. Hypothesis: Nusselt number was affected by the ratio of the nanoparticle size to the surface roughness. Heat transfer characteristics could be improved if the researchers selected an appropriate impingement system and selected the optimal levels of other factors. The surface coating with the TiO2 nanosolution also positively affected the heat transfer rate.

This article presents a study which sought to enhance heat transfer by employing a twin jet impingement mechanism (TJIM) and investigating the impact of the distance between the nozzles and plate on the Nusselt number (Nu) and heat transfer coefficient. This investigation was additionally based on the measurements of the heat flux temperature micro foil sensor and IR thermal imaging. A computational study of the cooling heated plate, through simulating the electronic components by the TJIM, was investigated using the RNG k-ε turbulence model. The jet-plate position was changed at the different jet-to-plate distances S = 1, 6, and 11 cm, Reynolds number = 17,000. The main flow structure, the static pressure, local and average Nus and heat transfer coefficient, were also examined. The findings have yielded new information about TJIM, and represent a new contribution about the flow and heat transfer characteristics of TJIM, and means of improving the rate of heat transfer in the passive heat transfer technique. The results of the various positions of the TJIM determined that the first model is, in fact, the best model for the heat transfer coefficient and the highest Nu, when S = 1 cm and H = 1 cm. Furthermore, the irregular distribution of the local Nu and the local heat transfer coefficient (h) on the impinged surface are due to the increase or decrease in the turbulence of flow on the measured surface.

Pulsating twin jets mechanism (PTJM) was developed in the present work to study the effect of pulsating twin jets mixing region on the enhancement of heat transfer. Controllable characteristics twin pulsed jets were the main objective of our design. The variable nozzle-nozzle distance was considered to study the effect of two jets interaction at the mixing region. Also, the phase change between the frequencies of twin jets was taken into account to develop PTJM. All of these factors in addition to the ability of producing high velocity pulsed jet led to more appropriate design for a comprehensive study of multijet impingement heat transfer problems. The performance of PTJM was verified by measuring the pulse profile at frequency of 20 Hz, where equal velocity peak of around 64 m/s for both jets was obtained. Moreover, the jet velocity profile at different pulsation frequencies was tested to verify system performance, so the results revealed reasonable velocity profile configuration. Furthermore, the effect of pulsation frequency on surface temperature of flat hot plate in the midpoint between twin jets was studied experimentally. Noticeable enhancement in heat transfer was obtained with the increasing of pulsation frequency.