Universiti Teknologi Malaysia

In this paper, the structural, electronic, and elastic properties of molybdenum disulfide (MoS2) in hexagonal and trigonal phases were investigated using first-principles calculations based on density functional theory (DFT) as implemented in the Quantum ESPRESSO package. Our findings from the structural and electronic properties of MoS2 show that bulk hexagonal and trigonal MoS2 phases have a calculated bandgap of 1.37 and 1.56 eV respectively, which is in good agreement with available theoretical and experimental results. The elastic properties show that both space groups of MoS2 are brittle at zero pressure and they also agree with Born's mechanical stability condition. The overall results place our new optimized MoS2 as a potential candidate for optoelectronic application.

This study analyzes the impact of ASEAN’s goal of achieving carbon neutrality by 2050 on climate change and coastal ecosystems by examining carbon emissions and energy usage from 2019 to 2050 using different scenarios to reduce emissions and meet global temperature goals. This research proposes strategies to reduce carbon emissions and mitigate climate change effects on coastal ecosystems, focusing on evaluating CO2 emissions from ASEAN’s coastal shipping sector. Geospatial data was used to analyze ship activity and develop carbon neutrality strategies. Various sources are used to gather data, including the Maritime Portal, exact Earth AIS, FASA and GFW. This study finds that container ships emitted 13.7 × 106 t of CO2 in 2019, with the transportation sector contributing 3.8% of the total greenhouse gas in 2020. Without regulations, CO2 emissions could increase fourfold by 2050. The study recommends implementing policies such as adopting clean fuels, energy efficiency standards and fuel-related regulations to reduce CO2 emissions by 65–80% by 2050. It also emphasizes the importance of cleaner technologies, regulatory considerations and collaboration, which would have positive implications for coastal ecosystems. This study is beneficial to professionals in the maritime and shipping industries, policy makers, environmental consultants, sustainability specialists, and international organizations.

An adaptive control approach for a three-phase grid-interfaced solar photovoltaic system based on the new Neuro-Fuzzy Inference System with Rain Optimization Algorithm (ANROA) methodology is proposed and discussed in this manuscript. This method incorporates an Adaptive Neuro-fuzzy Inference System (ANFIS) with a Rain Optimization Algorithm (ROA). The ANFIS controller has excellent maximum tracking capability because it includes features of both neural and fuzzy techniques. The ROA technique is in charge of controlling the voltage source converter switching. Avoiding power quality problems including voltage fluctuations, harmonics, and flickers as well as unbalanced loads and reactive power usage is the major goal. Besides, the proposed method performs at zero voltage regulation and unity power factor modes. The suggested control approach has been modeled and simulated, and its performance has been assessed using existing alternative methods. A statistical analysis of proposed and existing techniques has been also presented and discussed. The results of the simulations demonstrate that, when compared to alternative approaches, the suggested strategy may properly and effectively identify the best global solutions. Furthermore, the system’s robustness has been studied by using MATLAB/SIMULINK environment and experimentally by Field Programmable Gate Arrays Controller (FPGA)-based Hardware-in-Loop (HLL).

This study aims to integrate Free Learning and Physics Innovation in STEAM-based Renewable Energy Education to improve critical thinking skills in Era Society 5.0 in order to achieve the 2030 Sustainable Development Goals (SDG). This research uses a literature review method that collects and analyzes related articles. The results showed that integrating Free Learning and Physics Innovation in STEAM-based Renewable Energy Education is an effective approach to improving students’ critical thinking skills. Renewable energy education is a relevant and important topic in SDG 2030, and the STEAM approach helps students understand and overcome this challenge. Era Society 5.0 emphasizes technology integration, so the educational approach must constantly be updated and adapted to the times. The results of this literature review can assist educators, policymakers, and researchers in developing educational strategies that align with the times’ needs.

A digital learning environment can play a pivotal role in advancing the objectives of Goal 4 and, in doing so, can contribute to several other SDGs. This study purposed to investigate the impact of digital learning on sustainable growth in institutions by emphasizing the educational procedures that were implemented in extended years (three decades) throughout the global and broader countries. Furthermore, this research also analyzes the challenges and opportunities for digital learning in educational institutions, primarily to support the SDGs This research employs a descriptive bibliometric analysis, utilizing Scopus as the primary data source. The research findings indicate a consistent upward trend in publication rates each year, with articles being the most prevalent document type, followed by conference papers. Potential areas for future research include the integration of e-learning practices into various educational levels, from universities to high schools and early education. Additionally, there are opportunities to investigate the development of innovative learning techniques and the emergence of computer-assisted learning as an educational system. Notably, the most influential studies fall within the Q1 category. The implications of this research extend to providing a comprehensive overview of trends in DLE publications from 1993 to 2022 and their potential contributions to the SDGs. Furthermore, future researchers can build upon these findings to develop and enhance digital learning environments in educational contexts, ultimately contributing to the attainment of SDG goals.

Methane as an anthropogenic gas has an effect on the atmosphere and can be used as an alternative natural gas using adsorbent material. This research aims to determine the impact of activation conditions on the surface of fibers for zeolite-A crystal growth utilized for CH4 adsorption. Glass fiber and pineapple fiber have been treated with an alkali used in this research. The concentration of NaOH and fiber immersion time determine the activation conditions. The activation process altered the crystallinity of the surface-deposited zeolite-A. Characterization by XRD and SEM revealed that zeolite-A covered the surface of those fibers when the NaOH concentration was 4M and the immersion time was 24 h. Thermal analysis revealed that the composite of zeolite-A/fibers undergoes two weight loss processes prior to achieving stability. The methane adsorption gravimetric measurements for zeolite-A supported glass fiber (glass wool) and pineapple fiber with high crystallinities are 4.644% wt and 3.461% wt, respectively.

Landfill leachate, which is a complicated organic sewage water, presents substantial dangers to human health and the environment if not properly handled. Electrochemical technology has arisen as a promising strategy for effectively mitigating contaminants in landfill leachate. In this comprehensive review, we explore various theoretical and practical aspects of methods for treating landfill leachate. This exploration includes examining their performance, mechanisms, applications, associated challenges, existing issues, and potential strategies for enhancement, particularly in terms of cost-effectiveness. In addition, this critique provides a comparative investigation between these treatment approaches and the utilization of diverse kinds of microbial fuel cells (MFCs) in terms of their effectiveness in treating landfill leachate and generating power. The examination of these technologies also extends to their use in diverse global contexts, providing insights into operational parameters and regional variations. This extensive assessment serves the primary goal of assisting researchers in understanding the optimal methods for treating landfill leachate and comparing them to different types of MFCs. It offers a valuable resource for the large-scale design and implementation of processes that ensure both the safe treatment of landfill leachate and the generation of electricity. The review not only provides an overview of the current state of landfill leachate treatment but also identifies key challenges and sets the stage for future research directions, ultimately contributing to more sustainable and effective solutions in the management of this critical environmental issue.

Receptor-like kinases (RLKs) are plant proteins that form signaling circuits to transduce information through the plant cell membrane to the nucleus and activate processes that direct growth, development, stress response, and disease resistance. Upon sensing various environmental stress stimuli, RLKs interact with specific targets and recruit several other proteins to initiate the defense mechanism. Among many RLK subfamilies, leucine-rich repeat RLKs (LRR-RLKs) are the largest. Xa21, a member of LRR-RLK, is a vital receptor protein in rice plants that binds with bacterial RaxX21-sY, whereas OsSERK2 is a somatic embryogenic receptor kinase (SERK) that acts as a coreceptor in this process. This study focuses on the effect of a substitution mutation of aspartate128 with asparagine128 (D128N) in OsSERK2 on the interdependent binding pattern of the Xa21, RaxX21-sY, and OsSERK2 D128N proteins. The in silico results showed that the D128N mutation in OsSERK2 can significantly change the interaction pattern of the critical residues of the OsSERK2 and affects its receptor-ligand (Xa21-RaxX21-sY) interaction in the complex. These findings are expected to significantly contribute to the study of the structural basis of Xa21-mediated immunity and the first layer of plant defense mechanisms, thereby aiding further research on these structures and their phenotypic implications.

We have successfully synthesized ZnFe2O4/SiO2—Morus alba L. nanoparticles as a drug delivery agent. The nanostructural and optical properties of ZnFe2O4/SiO2—Morus alba L. were evaluated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy–energy dispersive X-ray (SEM–EDX) spectroscopy, transmission electron microscopy (TEM), and ultraviolet–visible spectroscopy. Antibacterial and drug delivery tests were conducted to examine the antibacterial activity and drug delivery performance of the nanoparticles, respectively. The peaks in the XRD patterns indicated the existence of ZnFe2O4 and SiO2 phases at 2θ = 35.4° and 22°–28°, respectively, in the sample. Meanwhile, the FTIR spectrum showed the functional group of ZnFe2O4—Morus alba L. at wavenumbers of 400–600 cm−1 and Si–O–Si at 1086 and 950 cm−1. The Si–O–Fe peak was also detected at 541–575 cm−1. The calculated bandgap energy was in the range of 3.003–3.218 eV. The TEM and SEM images revealed that the particle size varied in the range of 28.7–47.3 nm and confirmed the formation of a composite. The samples exhibited excellent antibacterial activity and inhibited the growth of S. aureus and E. coli by up to 72% and 78%, respectively. The samples also possessed a desirable doxorubicin (DOX) loading, indicated by the appearance of DOX absorption peaks at wavelengths of 200–250 nm and 450–550 nm. Herein, the increase in SiO2 composition can speed up the DOX release process. Thus, the synthesized samples in this work meet the riteria for drug delivery application.

This paper presents the control synthesis of a nonlinear sliding mode control, known as the “ natural logarithm sliding mode control” (lnSMC), for a general n-th order system. The lnSMC offers a simple and straightforward design approach because it only requires tuning two design parameters. The first parameter has a physical meaning corresponding to the bounds of the state variables, which can be easily determined without a trial-and-error process. The second parameter is related to the controller’s feedback gains, which ensure that the system dynamics converged to the sliding surface. Lyapunov stability theory is used to analyze the closed-loop system and finite-time convergence stability. As a case study, the natural logarithm sliding mode controller is designed to suppress the vibration in a simple spring-mass system and an active suspension system. The simulation study shows that the proposed controllers have significant vibration suppression performance. Furthermore, the simulation study indicates that the sliding mode controller designed by using the natural logarithm sliding manifold outperforms the standard linear sliding manifold counterpart. In addition, due to the nature of the nonlinear switching function that creates boundary states, lnSMC has a huge potential to be applied in a wider area of vibration control.

As a part of this work, organic − inorganic metal halide perovskite (\({\mathrm{CH}}_{3}{\mathrm{NH}}_{3}{\mathrm{PbI}}_{3}\)) films were grown at different annealing temperatures (60, 100, and 140 °C). The findings revealed that the morphological, optical, and structural properties were enhanced by annealing at 60 °C and 100 °C, while increasing the temperature to 140 °C led to the partial decomposition of perovskite into lead iodide (\({\mathrm{PbI}}_{2}\)). In addition, the self-powered photodetection properties of pristine \({\mathrm{CH}}_{3}{\mathrm{NH}}_{3}{\mathrm{PbI}}_{3}\) film, and \({\mathrm{CH}}_{3}{\mathrm{NH}}_{3}{\mathrm{PbI}}_{3}\) grown on ZnO QD-based film and ZnO/Al2O3 films were evaluated under illumination with blue (470 nm), green (530 nm), red (660 nm), and white light. The ZnO/\({\mathrm{CH}}_{3}{\mathrm{NH}}_{3}{\mathrm{PbI}}_{3}\) photodetector (PD) exhibited inferior photoresponse relative to the PD based on pristine \({\mathrm{CH}}_{3}{\mathrm{NH}}_{3}{\mathrm{PbI}}_{3}\) owing to the \({\mathrm{CH}}_{3}{\mathrm{NH}}_{3}{\mathrm{PbI}}_{3}\) degradation driven by the basic nature of ZnO QDs. On the other hand, insertion of Al2O3 as a passivation layer between ZnO QD-based film and MAPbI3 suppressed perovskite degradation and enhanced the PD photodetection properties. Upon illumination with blue (470 nm) light, the responsivity, detectivity, and ON/OFF current ratio values of the ZnO/Al2O3/\({\mathrm{CH}}_{3}{\mathrm{NH}}_{3}{\mathrm{PbI}}_{3}\) PD were calculated to be 71.05 mA/W, 5.61 × 1012 Jones, and 9.3 × 102, respectively. The enhanced photodetection performance was attributed to the effectiveness of the Al2O3 passivation layer in reducing the number of trap centers and hydroxyl groups at the ZnO film surface, as evident from XPS results.

As the global mean surface temperature continues to rise due to climate change, the impacts are not equally distributed worldwide, making regional assessments crucial. Bangladesh, a tropical monsoon region characterized by low-lying terrain, is particularly vulnerable to climate change effects. Yet, there has been a lack of analysis regarding potential shifts in thermal bioclimatic indicators (TBIs) in this region, a critical aspect of climate change adaptation. To address this gap, a study used a multimodel ensemble (MME) of 18 bias-corrected CMIP6 GCMs to project variations in 11 TBIs across Bangladesh for the near (2015–2044), mid (2045–2074), and far (2075–2100) futures under three SSPs: low (SSP126), medium (SSP245), and high (SSP585). By examining spatiotemporal changes in the ensemble mean, the study considered the base period (1985–2014) of each indicator for the respective future periods. The results of the study revealed that Bangladesh is likely to experience an increase in average annual temperature in the future, consistent with the global average. Depending on the SSP, the temperature rise could range from 0.62 to 1.85 °C for SSP126, 0.51–2.81 °C for SSP245, and 0.54–4.88 °C for SSP585. Furthermore, the study predicted a potential decrease in the diurnal temperature range (DTR) by − 0.17 to − 2.50 °C and a reduction of up to 30% in the ratio of mean diurnal temperature range to mean annual range. The projected temperature rise would vary significantly across regions, with the northeast and southeast experiencing increases between 0.14 and 0.39 °C, while the northwestern, central, and southwestern regions could see higher increases ranging from 0.17 to 2.66 °C. The study also highlighted a considerable increase in average temperature between the coldest and warmest quarters. Notably, the drier quarter would experience more substantial warming compared to the wettest quarter. These findings have important implications for climate change mitigation strategies in tropical monsoon regions like Bangladesh. Urgent action is needed to address the adverse consequences of global warming. Policymakers and stakeholders must understand these projected changes to implement measures that can reduce the impacts on agriculture, ecosystems, human health, and biodiversity. The study underscores the need to protect the well-being and sustainability of the nation in the face of a changing climate.

Water electrolysis is considered one of the major sources of green hydrogen as the fuel of the future. However, due to limited freshwater resources, more interest has been geared toward seawater electrolysis for hydrogen production. The development of effective and selective electrocatalysts from earth-abundant elements for oxygen evolution reaction (OER) as the bottleneck for seawater electrolysis is highly desirable. This work introduces novel Pd-doped Co nanoparticles encapsulated in graphite carbon shell electrode (Pd-doped CoNPs@C shell) as a highly active OER electrocatalyst towards alkaline seawater oxidation, which outperforms the state-of-the-art catalyst, RuO2. Significantly, Pd-doped CoNPs@C shell electrode exhibiting low OER overpotential of ≈213, ≈372, and ≈ 429 mV at 10, 50, and 100 mA/cm², respectively together with a small Tafel slope of ≈ 120 mV/dec than pure Co@C and Pd@C electrode in alkaline seawater media. The high catalytic activity at the aforementioned current density reveals decent selectivity, thus obviating the evolution of chloride reaction (CER), i.e., ∼490 mV, as competitive to the OER. Results indicated that Pd-doped Co nanoparticles encapsulated in graphite carbon shell (Pd-doped CoNPs@C electrode) could be a very promising candidate for seawater electrolysis.

This research focused on the effects affecting ammonia removal in synthetic wastewater by Rhodobacter sp. using one factor at a time method (OFAT). Rhodobacter sp.are able to remove ammonia from synthetic wastewater due to its ability to assimilate ammonia. The ammonia removal experiment was conducted under different factors; Rodobacter sp. inoculum size (2%, 4%, 6%), incubation temperature (20°C, 25°C, 30°C, 37°C, 40°C), initial pH of synthetic wastewater (5,6,7,8,9) and initial NH4Cl concentration (5 mg/L, 10 mg/L, 15 mg/L) for four days of incubation period. Then, the solution was tested using Nessler reagent which will produce yellow colour when it reacts with ammonia. The intensity of colour is proportional to the ammonia concentration. This experiment was followed by ammonia quantitative analysis via spectrophotometer at 425 nm. The results obtained were then calculated to get the percentage of ammonia removal by PNSB. The result revealed that the bacterium can achieved 97.90 % efficiency of total ammonia removal at optimum growth condition with 6% of inoculum size, incubation temperature at 30°C and initial pH 7. As a conclusion, this Rhodobacter sp. can therefore serve as a good candidate in wastewater treatment for ammonia removal.

The purpose of this project is to survey the terrestrial gamma radiation dose (TGRD) rate levels in Universiti Teknologi Malaysia (UTM), Johor Bahru, Malaysia. The measurement of the TGRD rate was carried out using an RDS-31 detector. Based on the survey of 60 locations in UTM, an isodose map was constructed by using ArcGIS online software version 9.3 to show the radiation level distribution. Color codes were used to reflect the radiation levels: green for relatively low TGRD rates of 0.05-0.12 μSv/h, yellow for readings from 0.13-0.20 μSv/h, and red indicates dose rates with 0.21-0.40 μSv/h. Areas of relatively high dose rates can be observed from the plotted isodose map. It was found that the average TGRD rate of UTM is 0.16 ± 0.035 μSv/h which is similar to Johor’s average of 0.163 μSv/h. It is also higher than the worldwide average of 0.059 μSv/h and Malaysia’s average of 0.092 μSv/h. A comparison of dose rates from other studies can also be found in this article.

We propose and demonstrate a passively mode-locked all-fiber laser utilizing a multimode interference effect in graded-index multimode fiber (GIMF). The mode-locking is obtained due to the Kerr effect in GIMF, which induces the intensity modulation inside the ring cavity laser. We obtain stable soliton mode-locked pulses at a center wavelength of 1574.1 nm, with a fixed repetition rate of 22 MHz and a pulse duration of 650 fs, when the pump power is changed in the range from 66.2 to 140.0 mW. The maximum average output power and pulse energy are recorded at 9.82 mW and 448 pJ, respectively, at a pump power of 140 mW. This proves that a nonlinear optical response in GIMF can be used as a new modulation mechanism for obtaining ultra-short pulses based on all-fiber ring cavity.

The constant increase in worldwide per capita consumption of fish indicates the need for reliable and viable sources of fish, and aquaculture fits these criteria. Aquaculture has continued to make a significant contribution to total fisheries production over the last few decades. The significant progress in aquaculture has been largely attributed to the intensification of production and increasing dependency on formulated food. Among the major challenges in aquaculture is aquaculture feed, or in short, aquafeed, which may represent up to 80% of total operational costs. Due to escalating prices and unsustainable resources of aquafeed ingredients, especially fish meal, fish oils, and soybean meal, many substitutes are utilised, mainly animal by-products and animal waste, which is a concern under Islamic jurisprudence. This concern is quite substantial if aquaculture producers are vying for the halal market. Hence, it is important for them to understand this aspect of Islamic law. This paper reviews the current status of aquafeed ingredients and the classical Islamic jurisprudence pertaining to this issue. References to current decrees and standards by major Muslim countries and Islamic authorities are also presented, followed by options and avenues for remediation.