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Energy and Environmental HarmonyHydrogen, the most abundant element in the universe, is increasingly recognized for its potential to serve as a clean energy carrier. Hydrogen is a clean energy source that produces no emissions when used, making it a good choice for reducing air pollution. Additionally, it is an abundant energy source that can be produced from a variety of sources such as air, biomass, and natural gas. Unlike fossil fuels, hydrogen combustion only produces water, making it an environmentally friendly alternative. There are two primary methods for hydrogen production: steam reforming of methane, which results in significant CO2 emissions, and electrolysis, the splitting of water into oxygen and hydrogen using electricity. When this electricity is derived from renewable sources like wind or solar, the result is green renewable energy, such as hydrogen (H2) gas, which is seen as key to a sustainable energy future. Globally, the majority of hydrogen gas production still relies on natural gas, resulting in significant greenhouse gas emissions. The challenge is to increase the share of green hydrogen to make this energy source truly sustainable and environmentally benign.The urgency of adopting hydrogen technologies is amplified by the need to meet climate goals set by global agreements like the Paris Accord. According to forecasts from University College London, to limit global warming to 2°C, it is necessary to keep a third of all oil, half of all natural gas, and 80% of coal in the ground by 2050. Achieving these targets requires a shift to renewable energy sources that do not solely rely on the intermittent availability of wind and solar. The transition to hydrogen is also driven by practical needs in the energy market. For instance, the recent energy shortages in the UK, exacerbated by non-wind days in the North Sea, highlighted the limitations of current renewable energy infrastructures and the necessity for alternatives like hydrogen that can provide reliable, continuous power. Hydrogen gas can be used as an energy source, energy storage, and energy carrier, and also used for infrastructure purposes. This gas is particularly suited for heavy industries and long-haul transport where direct electrification is impractical. Industries such as steel, cement, and heavy manufacturing, which are significant contributors to carbon emissions, stand to gain substantial benefits from transitioning to hydrogen. For instance, replacing coal in steel production with hydrogen can drastically cut emissions, helping to decarbonize a notoriously difficult sector. Companies like ThyssenKrupp and Salzgitter AG are pioneering the shift to hydrogen-based processes. Similarly, the chemical industry benefits from green hydrogen in ammonia synthesis, reducing the overall environmental impact of chemical production. Economic and Financial Challenges The path to a hydrogen-driven future is fraught with technical and economic hurdles. Historically, the perception of hydrogen has been marred by safety concerns, notably exemplified by the Hindenburg disaster. Critics argue that direct electrification may offer greater efficiency for certain applications compared to hydrogen. Additionally, the production of hydrogen is characterized by high energy intensity, necessitating substantial electricity inputs. When sourced from non-renewable energy, this can undermine its environmental advantages. In 2020, producing one kilogram of green hydrogen cost between around $5 and $7. This is significantly higher if the source is coal ($1.00 to $1.80 per kg) and natural gas ($1.40 to $2.40 per kg). The range of cost heavily depends on the location. Financially, the transition to hydrogen technology requires considerable investment. Currently, there are over 350 large-scale projects worldwide, with total projected expenditures upwards of $500 billion. These projects span various applications from industrial processes to transportation and energy storage, indicating a growing confidence in hydrogen’s role in reducing carbon footprints. The U.S. alone, through a recent bipartisan infrastructure bill, has allocated $9.5 billion towards hydrogen initiatives, including the creation of hydrogen hubs and the advancement of hydrogen transportation and research. This substantial investment underscores the commitment to integrating hydrogen into the national energy strategy, aiming to ensure a stable, reliable energy supply. The commitment to hydrogen technology is also robust, with countries such as Germany dedicating approximately €7 billion to hydrogen projects. The country committed to establishing a core hydrogen grid extending 1,800 kilometers by 2027-2028 and is boosting its domestic electrolyzer capacity to at least 10 gigawatts by 2030. The project, located near Puerto Llano, Spain, is part of Iberdrola's broader plan to invest €3 billion in hydrogen technology by 2030. The goal is to link renewable energy production directly to hydrogen and ammonia production facilities, enhancing the sustainability of industrial processes. India's central government has committed a significant investment of (approximately $2.5 billion) to the National Green Hydrogen Mission. This initiative is designed to create export opportunities, decarbonize energy production, and develop local manufacturing capabilities. The ambitious goal is to reduce the production cost of green hydrogen from the current range of $4.5 per kg to about $1.2 per kg. China targeting the deployment of 1 million fuel-cell vehicles by 2030. These investments underscore a strong belief in hydrogen’s capacity to support a low-carbon economy. Hydrogen and Ammonia Nexus Hydrogen's potential is limited by its low density at room temperature, which is roughly one-third that of natural gas. This means that hydrogen either needs to be cooled to -250°C to become a liquid or compressed to up to 300 times atmospheric pressure in order to be transported. This introduces significant energy losses in hydrogen production, estimated at about 30% of overall efficiency. Despite these challenges, the energy sector sees hydrogen as an attractive option because, in its compressed form, hydrogen contains approximately 40,000 Watt hours of energy per kilogram, significantly more than the best lithium-ion batteries, which hold about 280 Watt-hours per kilogram. Ammonia gas has several advantages over hydrogen gas. It is easier to liquefy, requiring only -33°C, and needs to be compressed to just 10 times atmospheric pressure. Additionally, ammonia does not react with steel or leak from containers as hydrogen does, making it a superior carrier. Indeed, ammonia contains 50% more hydrogen by volume than hydrogen itself and converts back into hydrogen and nitrogen when needed without the intense conditions required for storing pure hydrogen gas. Parallel to hydrogen, ammonia production is undergoing a transformation. Traditionally reliant on the Haber-Bosch process, which is energy-intensive and carbon-heavy. This process is responsible for about 2% of the world's fossil fuels and accounts for 1.2% of global CO2 emissions. Evidently, this contributes significantly to CO2 emissions, nitrate pollution, and nitrous oxide emissions. Ammonia is a critical industrial chemical used primarily in agricultural fertilizers and in the manufacture of plastics and pharmaceuticals. With global production exceeding 200 million tonnes annually in a market worth nearly $100 billion and growing. Due to its potential as a clean alternative to fossil fuels, the efficient and environmentally friendly production of ammonia is increasingly vital. To achieve the vision of fully green ammonia, the industry must transition away from hybrid and conventional plants. The future lies in using electrochemical cells that operate solely on electricity and catalysts to combine air and water components into ammonia. This process does not require the high heat and pressure typical of traditional ammonia synthesis. However, there is a challenge in producing ammonia efficiently at normal temperatures and pressures. Researchers are currently working towards developing a single cell that can effectively produce ammonia under these conditions. Monash University’s breakthrough in synthesizing ammonia from water and air using renewable energy illustrates the potential for significant reductions in energy consumption and carbon emissions. This method, if scalable, could revolutionize ammonia production and provide a blueprint for clean industrial processes worldwide. This new process, detailed in the online journal Science, has demonstrated ammonia production rates significantly closer to industrial targets than previous attempts at electrolytic ammonia synthesis. The team has established a startup, Jupiter Ionics, which has already attracted $1.8 million in seed investment. Future Potential Ongoing advancements in hydrogen production, such as improved electrolysis techniques and the scaling up of infrastructure, are critical. The development of green ammonia as a derivative of hydrogen for easy storage and transport is also a promising avenue, particularly for sectors like maritime shipping, transportation, and heavy industry where traditional battery storage is unfeasible. Whether hydrogen or battery electrification will dominate the future of transport remains to be seen, but the integration of hydrogen into global energy systems represents a significant step toward achieving a sustainable and clean energy future.

Air pollution has become a global issue and contributes significantly to climate change, mainly due to the massive energy consumption in industry and the transportation sector. Emissions of harmful gases from burning fuels such as NOx and SO2 are the most significant sources of environmental pollution, which have negative impacts on the environment, such as the greenhouse effect, damage to the ozone layer, photochemical smog, and acid rain, and can interfere with the respiratory system in humans. This study utilizes hollow fiber membrane modules, which act as a reactor on the shell side of the membrane module and a gas distributor by the membrane fiber to remove NOx and SO2 spontaneously. The oxidant solutions used were a pair of hydrogen peroxide and sodium hydroxide (H2O2-NaOH) solutions, a pair of sodium chlorite and sodium hydroxide (NaClO2-NaOH) solutions, and a pair of sodium chlorate and sodium hydroxide (NaClO3-NaOH) solutions. Based on the results of experiments, SO2 can be removed entirely in the process, while NOx depends on the feed gas flow rate and the concentration of the oxidant solution used. H2O2 is the most effective oxidizing agent in removing NOx and SO2 because of its higher oxidative properties than NaCLO2 and NaClO3. The increase in feed gas flow rate resulted in a decrease in the efficiency of NOx removal even though the NOx mass transfer flux and NOx loading increased. Meanwhile, an increase in the concentration of oxidants increases the efficiency of NOx removal and mass transfer flux but decreases NOx loading. Based on the experimental results, the maximum NOx removal efficiency achieved by the oxidant solutions is 93.9, 91.1, and 88.3% for H2O2-NaOH, NaClO2-NaOH, and NaClO3-NaOH, respectively.

Hazardous pollutants such as NOx (NO and NO2) and SO2 generally come from fossil fuel combustion, harm the human respiratory system, and damage environmental ecosystems. The conventional technology that has been used so far consists of two methods: FGD (Flue Gas Desulfurization) and SCR (Selective Catalytic Reduction) or SNCR (Selective Non-Catalytic Reduction) to remove SO2 and NOx. The study aims to examine the performance of polysulfone membranes in removing NOx and SO2 simultaneously using hydrogen peroxide (H2O2) and sodium hydroxide (NaOH) solutions as absorbents. The presence of H2O2 and NaOH in absorbent solutions plays a role in oxidizing NOx into soluble species in water and in absorbing SO2 gas, respectively. During the experiment, the feed gas flowed through the lumen fiber and then passed through the fiber to the shell side of the membrane module, where the reaction happened between NOx and SO2 and the absorbent. The experimental results showed that the presence of SO2 affected the NOx reduction efficiency. The NOx and SO2 removal efficiencies decreased with the feed gas flow. This study's maximum NOx and SO2 reduction efficiencies were 93.9 and 99.8%, respectively.

Today we are facing the era of the industrial revolution 4.0, which brings many changes in all fields. In this era, there are massive changes in various fields through the combination of technology that reduces the barriers between the physical and digital worlds. In addition, various problems in making this earth better is also a task that must be solved. This is marked by the global desire to create sustainable development as stated in the Sustainable Development Goals (SDGs) by 2030. These two momentums are ultimately interrelated conditions. The industrial revolution 4.0 brings many changes with all the consequences, one of which is the emergence of disruption in this era. However, the industrial revolution 4.0. can also be used to achieve Sustainable Development Goals (SDGs). The development of technology is also able to align with the SDG’s goal, namely improving the efficiency of the production process and quality of the products, both in the manufacturing and service industries, including in the field of education. For example, the internet allows distance learning at a low cost. In addition, Artificial Intelligence (AI) technology can determine more accurately the allocation of time and teaching materials that are more effective and efficient. The SDGs have become a new point in the globalization development in this 4.0 Industrial Revolution Era. This means that industrial revolution 4.0 must not hinder the achievement of the SDGs goals. On the contrary, industrial revolution 4.0 must be able to accelerate the achievement of the SDGs goals. For example, by further encouraging the acceleration of the green industry 4.0 to achieve the Sustainable Development Goals (SDGs), where the acceleration of the green industry is carried out using high technology in accordance with the push for industrial development 4.0. To address the above issues, the Digital Futures International Congress (DIFCON 2022) was held on July 25-27, 2022. DIFCON provides a multidisciplinary platform for gathering scholars from different disciplinary backgrounds to disseminate ongoing research related to the digital futures of our society, following the “2030 Agenda for Sustainable Development”. Of the papers presented at DIFCON 2022, the top 20 papers have been selected by the IJTech’s editor-in-charge for publication in this special edition of IJTech and are summarized as follows.The first paper, written by Long, Ooi, Le, Thiet, Ai, An, Hudson, Tan, and Van, determine the best leadership thinking combination that will enable Vietnamese leaders to successfully implement the fourth industrial revolution (4IR) in Vietnam. The study indicates that Blockchain Leadership is the appropriate model to achieve success for organizations in the era of 4IR and beyond. It is, therefore, essential for Government to endorse and support the development of blockchain leadership, which is essential for the effective implementation of 4IR by the business organizations in their respective countries.The second paper, written by Anh, Binh, Long, Ai, Tan, and Van, identifies key factors that Vietnam should focus on for a comprehensive national strategy to develop within the fourth industrial revolution (4IR). Three factors were identified as the key elements of a strategy for social-economic development in Vietnam, including human resources, policies, and infrastructure. The study also reveals an optimistic attitude, among policymakers, researchers, and enterprise managers, toward the rapid readiness and adoption of 4IR in Vietnam.The third paper, written by Mudzar and Chew, identifies new skills required by the workforce in the Fourth Industrial Revolution. Based on the review of relevant literature, the authors identify that creative thinking, decision-making, critical thinking, negotiation, and persuasion will be required, as machines lack these abilities. While this literature review covers a broad range of skills needed for the Fourth Industrial Revolution, it may not apply to all organizations. An external variable, such as education standards, may influence skills that different firms might require.The fourth paper, written by Rathidevi, Aravindan, and Choong, develops a conceptual model to examine the entrepreneurial orientation (EO) of undergraduates, which leads to entrepreneurial career intention (ECI) in Malaysia. This model expected to foster understanding on phenomena of ECI among female undergraduates, laying the foundation for boosting women’s participation in entrepreneurship.The fifth paper, written by Chan, Shen, Rashid, Abdullah, Xin, and Tung, develops an innovative mobile application, Your 2 Home, designed to help foreign workers in Malaysia understand their human rights. With the various features in the app, it is hoped that foreign workers in Malaysia will have a better understanding of their rights and have an excellent platform to give advice or even assistance. Hence, this study recommends a concept of a digital solution that can be used to solve human rights issues among foreign workers in Malaysia. The sixth paper, written by Moganadas and Goh, analyze the effect of digital employee experience (DEX) on organisational outcomes and measurement mechanism. Based on content analysis on a comprehensive literature review of DEX constructs (i.e., digital technologies and environment, digital culture and work practices, and individual characteristics and demographics), the results showed that DEX has positive implications in the establishment of the total employee experience (EX) management in workplaces.The seventh paper, written by Teoh, Mohamed, Mohd, Rosid, and Yusof, investigates how teachers and parents in a rural mathematics community in Malaysia create opportunities for students to participate in mathematics education. Based on a case study to obtain qualitative data via interview, the results revealed that the teachers and parents were equally concerned about their children’s education and focused on mentoring them. This study provides input on strategies used to engage students in mathematics education. The eighth paper, written by Neo, Lee, Tan, Neo, Tan, Mahendru, and Ismat, investigates the impact of multimedia-based AI chatbots, named MERLIN, as a scaffolding agent to assist student learning during their independent online learning times. The results showed that students were motivated to learn more using MERLIN, improved their learning, and wanted more chatbots in their other courses. These findings have important implications for using AI chatbots as a scaffolding and instructional tool in 21st-century learning environments.The ninth paper, written by Tan, Lim and Diong, develops a model to predict the users’ quality of experience (QoE) based on the network monitoring data of a 5G network during an online gaming session. The proposed ANN model achieves prediction accuracy of close to 80% using the 30 most relevant features derived from the radio access network monitoring data.The tenth paper, written by Kho, Fauzi, and Lim, proposes a technique to perform image processing without requiring the use of external DDR or HBM RAM memory. A chunk processor has been developed to read and process kernels without the need to store the entire image frame. This reduces the memory requirements significantly without losing the quality of the processed images.The eleventh paper, written by Haw, Amin, Naveen, and Ng, evaluates the performance of the three labelling schemes (i.e., ORD-GAP, ORDPath, ME Labeling) in terms of robustness and efficiency to support storage and query retrieval. The results showed that ORD-GAP does not have the minimum storage size compared to ORDPath, because it reserved a gap between nodes to maintain later insertion. While ME Labeling took a long time on path and twig queries, especially for queries with A-D and mixed relationships. The twelfth paper, written by Harun, Dorasamy, and Ahmad, examines the interactions among people, processes, technology, and STP (Science and Technology Park) organization on the successful implementation and use of ERP (Enterprise Resource Planning). The results showed that implementing ERP enhances an organization's capacity and performance. In addition, this study found that STP organizations focus on the benefits of implementing ERP rather than the associated costs. The thirteenth paper, written by Salim, Yatim, Said, Masuod, Mustafa, and Ismail, examines performance predictors from the perspective of mosque co-operators through the lens of Intellectual Capital Theory. The study found that the top three predictors of performance for mosque co-operatives are board members' competencies, spirituality, managers' competencies, and stakeholders' support, indicating the essentials of human capital, relational capital, and spiritual capital. This study provides initial insights to regulators, policymakers, and co-operators in enhancing the performance of religious-based co-operatives. The fourteenth paper, written by Ong, Rahim, Lim, and Nizat, develops the technology adoption journey map (TAJM) to plan and study the farmers' technology adoption based on the Diffusion of Innovation (DOI) theory and the Customer Journey Map (CJM). To facilitate the mass adoption of technology, this study suggests documenting the experiences of innovators and early adopters of the technology as a guide in building the technology adoption journey map of the early majority. The fifteenth paper, written by Bai and Wong, develops a conceptual framework based on a literature review to address the insufficiency of visual and verbal elements of the existing herbal tea (i.e., Ningxia’s Eight Treasures Tea) packaging design to articulate its ‘values’ as a cultural object to the public. The proposed conceptual framework also serves as an example for the future creative practice of packaging design of other cultural objects to convey its cultural values through the visual and verbal elements and make the younger generation aware of the unique culture of the objects. The sixteenth paper, written by Hossain, Heng, Lee, Ong, and Islam, examines the impact of green human resource management (GHRM), top management commitment (TMC), and green culture (GC) on green performance (GP) of Palm oil companies (POCs) in Malaysia. The study found significant positive impacts of GHRM, TMC, and GC on GP. Moreover, the observed results highlight the importance of GC and TMC in implementing green procedures to create positive GP.The seventeenth paper, written by Valan, De Cruz, Jacob, and Djearamane, evaluates the potential of using A. Malaccensis leave extract as a biogenic medium to generate CuO NPs with antimicrobial potential. The results demonstrated that the boiled leaf extract reacted with 5 mM CuSO4.5H2O at pH 6 and incubated under non-shaking conditions at 70°C, resulting in a high rate of CuO NPs formation, depicting a UV absorbance peak of 430 nm. The eighteenth paper, written by Jayabalan, Dorasamy, and Raman, examines the effect of pretest and pilot tests on the methodological reliability of research instruments and suggests that it should be a common step in research instrument development. A well-planned and administered pilot study could improve the quality of the research since the findings may be used to influence subsequent stages of the research.The nineteenth paper, written by Seek, Kok, Lim, and Liew, evaluates the energy absorption capacity of a few common lattice structures printed out of PLA using fused deposition modelling and proposes an improved lattice structure. Simple cubic (SC), honeycomb (HC), body-centered cubic (BCC), and novel PeckGy80 (PG80) lattice structures were subjected to compressive tests. The results showed that energy absorption of the lattice structure was closely related to the deformation modes, where progressive folding of printed layers from the bottom up, such as that in PG80, is much preferred for energy absorption. The twentieth paper, written by Lau, Kok, Chen, and Tso, proposes improving existing spring-mass-damper models by accounting for the human-structure dynamic interaction during sideways fall to better predict peak impact force on the hip. The predicted peak hip impact forces were compared to measured or simulated results in the literature and found to agree reasonably. Simulation results show that interactions with impact surfaces with lower stiffness can reduce the value of peak impact force applied on the hip by at least 16%.

Over the past two years, the COVID-19 pandemic has significantly affected all aspects of human life. The pandemic has become an issue of serious global concern in both developing and developed countries, with impacts including rapidly changing health and demographic conditions, threatened food security, declining quality of education at all levels, declining clean water access and availability, declining trade, economic, and industrial sectors, and a lack of efficient energy sources to secure communities.These challenges necessitate swift responses to provide alternative solutions for global transformation toward sustainable development and improved living conditions at the local and global levels. The active role of universities in addressing these challenges is significant, as they allow researchers to propose advanced and applied technologies, as well as create efficient processes and innovative products. Triggering change, universities are leading institutions in transforming policy into concrete action. In addition, the collaborative study and research among universities and research centers, experts, industry, governmental and non-governmental organizations, and policymakers fosters and strengthens their collective ability to provide a higher quality of life and a more sustainable society around the world. Research on how to raise sustainability awareness and enhance regional collaboration to create a more sustainable society is also an important issue. Societal transformation through the application of digital technology, nurturing economic development, controlling rapid urban population growth, and building more intelligent cities (e.g., intelligenttransportation systems) while considering environmental aspects are essential for future sustainable urban development. This sustainability awareness is crucial in preventing environmental destruction, enhancing social participation, and improving the economic impacts of reusing certain technologies.To address the above issues, the 17th International Conference on Quality in Research (QiR) was virtually held October 13–15, 2021, in conjunction with the 6th International Tropical Renewable Energy Conference (i-TREC) and the 2th CSID AUN-SCUD International Conference on Sustainable Infrastructure and Urban Development (CAIC-SIUD). The QiR and i-TREC conferences focus on resiliency and adaptability in a post-pandemic world, exploring technology for a greener environment. The theme of the AUN-SCUD conference was shaping resiliency and sustainable futures through digitalization, technologies, and added value in developing sustainable infrastructure and resilient smart cities. Furthermore, the conference highlighted the role of digital technology in transforming cities and fulfilling Sustainable Development Goal (SDG) 9: Industry, Innovation, and Infrastructure, as driven by the three-pronged principles of Industry 4.0, Nature 5.0, and Society 5.0

The COVID-19 pandemic is still affecting many aspects of human life. Many efforts have been carried out by many parties in the fields of health and demographics, food security, secure and clean water, green and efficient energy sources, climate change, quality education and secure communities. The response of many scientists and technologists during this pandemic have successfully facilitated progress in many areas, such as effective vaccines to prevent further spreading of the pandemic and medical devices needed by many patients affected by COVID-19. In another domain, the policy responses of governments to the COVID-19 crisis have demonstrated that many major economies are capable of unprecedented and drastic action when it is called for. Responding to these many challenges requires engagement, specifically in the research domain, at any level, locally and globally. The 17th International Conference on Quality in Research (QiR) 2021 was held to address these issues. Due to the global pandemic situation, the QiR 2021 was held online. Presenting the theme of “Resilience and Adaptability for a Post-Pandemic World: Exploring Technology for Our Green Environment,” the QiR 2021 brought many research papers discussing the role of the science and technology during the pandemic. In this edition of the International Journal of Technology, we are proudly presenting 20 articles selected from the QiR 2021 and make them available to readers worldwide by highlighting research and development in various fields during the COVID-19 pandemic.

Nitrogen oxide (NOx) is one of the polluting gases harmful to humans and the environment. Nitrous oxide gas is mostly found in air, namely nitrogen monoxide (NO) and nitrogen dioxide (NO2). Nitrogen oxide gas in the air, which mostly comes from exhaust gases, needs to be reduced to minimize the threats to humans and the environment and comply with applicable regulations regarding hazards. The absorption process with a membrane contactor is an alternative to reduce NOx concentrations in the air. This study evaluates the hollow fiber membrane modules' performance in the NOx absorption process using sodium chlorate (NaClO3) and sodium hydroxide (NaOH) together as an absorbent solution. Based on the experimental results, the NOx reduction efficiency increased from 96.3 to 99.2% and from 99.4 to 99.7% with an increase in the concentration of NaClO3 from 0.02 to 0.05 M and the number of fibers in the membrane module from 50 to 150. However, the absorption efficiency declined from 99.7 to 99.2% by increasing the feed gas flow rate from 100 to 200 mL/min. The highest value of NOx reduction efficiency, the overall mass transfer coefficient, the flux, and the NOx loading obtained in the study were 99.7%, 0.01743 cm s-1, 9.510´10-8 mmole cm-2 s-1, and 0.026 mole NOx/mole NaClO3, respectively.

Utilizing Industry 4.0 technologies to create a sustainable energy industry enables a decentralized energy system in which energy can be effectively produced, managed, and controlled from local resources. Furthermore, the technologies also enable data capture and analysis to improve energy performance. As digital energy is being developed and increasingly decentralized, renewable energy is now a more attractive option for creating sustainable development. The technologies are capable of integrating different energy sources to respond to an increasingly demanding and distributed market by providing sustainable and efficient resources. The technologies of the fourth industrial revolution (Industry 4.0) are already being used in the energy sector to transform the business processes of the industry. Energy management systems based on emerging technologies, including artificial intelligence (AI), internet of things (IoT), big data, blockchain, and machine learning (ML), have been used to support industry players in analyzing the energy market, improving the supply–demand chain, real-time monitoring, and generating more options for using alternative sources of energy, such as storage devices, fuel cells, and intelligent energy performance. The optimization of the energy industry can be achieved through energy production and distribution efficiency by the digitization of manufacturing processes and service delivery. Optimized energy pricing and capital resources, predictive operation and maintenance plans, efficiency of energy usage, and further maximizing asset lifetime and usage are among the solutions produced from the technologies of Industry 4.0. These technologies are set to transform the energy industry to being more sustainable. This transformation has happened through the provision of integrated information in both planning and operational processes. Industry 4.0 technologies contribute to the efficiency and effectiveness of energy product life-cycles and value chains, therefore impacting business strategies to produce better energy management systems. Smart energy ecosystems that employ cyber-physical systems enhance all production and consumption energy chain processes. Smart applications in energy production and usage consumption processes can be used efficiently in managing and optimizing energy, such as by storing energy on demand or reducing consumption. Utilizing Industry 4.0 technologies to create a sustainable energy industry enables a decentralized energy system in which energy can be effectively produced, managed, and controlled from local resources. Furthermore, the technologies also enable data capture and analysis to improve energy performance. As digital energy is being developed and increasingly decentralized, renewable energy is now a more attractive option for creating sustainable development. The technologies are capable of integrating different energy sources to respond to an increasingly demanding and distributed market by providing sustainable and efficient resources.

The current need to reduce dependence on non-renewable fuels has contributed a lot to the rapid growth of renewable energy systems and electric vehicles. One of the exciting sources of energy storage is the battery. The development of lithium-based batteries is an exciting trend and is continuously being developed for long life and high-level battery quality. Batteries are considered a primary energy storage source. They are essential materials for many applications such as vehicles and electronic devices, including laptops, mobile phones, watches, etc. With the increasing demand and use of batteries globally for many applications, much research on advanced batteries has been interested in improving their performance, significantly to extend their safety and prolong their service life. The type of batteries and some external parameters, including voltage, current, and temperature, are essential to further exploration. Research on how to minimize the pollution from after-used batteries is also needed since electronic waste cannot be disposed into nature without prior treatment. This is important in preventing environmental destruction and supporting environmental sustainability, in addition to the economic impact of reusing certain technologies. Furthermore, with the advancement of civilization and technology, everything related to engineering and sciences can be developed according to its functions and humans' need. To address the above issues, the 5th International Tropical Renewable Energy Conference (i-TREC) was held on October 29-30, 2020, via online conference. The i-TREC is an annual event organized by the Tropical Research Energy Center, Faculty of Engineering Universitas Indonesia (TREC FTUI). The theme of this conference is the role of renewable and clean energy in supporting sustainable development goals. From the papers presented there, 18 paper have been selected for publication in IJTech. These 18 papers are summarized below.

Today, drugs and vaccines for treating coronavirus disease 2019 (COVID-19) are being developed in Russia, China, the USA, Canada, Turkey, Germany, the UK, and Indonesia. Not all drugs for treating COVID-19 have the same functions or target the same aspects of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), the cause of COVID-19. Very recently, some vaccines have been reported to effectively protect against COVID-19. Clinical vaccine trials are in phase 3 in several countries, including Indonesia, Turkey, Chile and Brazil. A virus is an intracellular parasite with a very simple structure. Viruses lack their own metabolism and thus require a host to replicate. That is why washing one’s hands with soap is the first step in preventing the spread of viruses with a lipid membrane, such as SARS-CoV-2. Soap effectively destroys such viruses because they are self-assembled structures. However, soap cannot be used to destroy the virus within a host because the same process that destroys the virus also destroys human cells. At the moment, much research in the area of nanotechnology is ongoing. Quantum dots (QDs) have been incorporated in many nanotechnological treatments, including drug delivery, bioimaging of cancer cells, and cancer diagnosis and treatment. Many researchers are investigating the use of new materials to treat COVID-19; possible therapies employ modified graphenes and QDs, among others. QDs are multifunctional crystalline semiconductors on a nanometer scale. Based on our studies, this QDs has fewer coordinating molecules on the surface. Nanometer-sized QDs are thermodynamically unstable but can be kept in a colloidal form to maintain stability. Due to their unique optical properties, QDs have significant potential for biomedical applications, including biomedical imaging, biosensors, drug delivery, clinical diagnosis, photodynamic therapy, DNA hybridization, and RNA profiling. Very recently, the potential of QDs for targeting virus cells has received attention. This function could be used to inhibit the activity of COVID-19. The use of QDs to treat COVID-19 still needs more evaluation and investigation. QDscan be functioned and coated with other molecules to improve their drug delivery profile. The chemical functionality of the surface of a QD can also be controlled by a capping agent such as Schiff base compound, which provides colloidal stability, prevents agglomeration and uncontrolled growth, increases solubility, and extends the exciton lifetime of QDs.The development of QDs and of nanostructured semiconductor crystals (which are usually under 10 nm in size) has opened new horizons in nanoscience and nanotechnology. QDs have been used in a wide range of applications in various fields, including biochemistry, physical chemistry, biomedicine, medicine, pharmaceuticals, microscopy, and engineering. QDs are also a powerful imaging probe for diagnostics and prognostics. The development and manufacture of bioengineering and medical equipment and devices has become more efficient, and computational modelling and simulations are now used to gather insights into new products.

As a type of gas that contributes to air pollution, nitrogen oxide (NOx) has harmful effects on humans and the environment. Among several types of NOx, nitric oxide (NO) and nitrogen dioxide (NO2) are most commonly found in air. The utilization of membranes as reactors is a system that combines chemical reactions with the separation process through membranes to increase the conversion of the reaction. This study investigated the absorption process by utilizing a hollow fiber membrane module (polysulfone) as a bubble reactor with H2O2 (0.5 wt.%) and HNO3 (0.5M) as the absorbent. NOx feed gas was flown into the tube side of the membrane; the shell side was filled with static H2O2 and HNO3 and the shell input and the tube output flow were closed to create gas bubbles. The experimental results showed that the absorption efficiency increased, but the mass transfer coefficient and flux decreased as the number of fibers in the membrane module increased at the same feed gas flow rate. The NOx loading is relatively constant as the amount of fiber in the membrane module increased at the same feed gas flow rate. The experimental results also showed that the mass transfer coefficient, flux, and NOx loading increased with increasing feed gas flow rate, but the absorption efficiency decreased when using the same number of fibers in the membrane module. The maximum NOx absorption efficiency achieved in this study was 94.6% at the feed gas flow rate of 0.1 L/min, using a membrane module with 48 fibers.

Materials science is an interdisciplinary engineering and science area covering the nature of materials and their applications in various fields of science, chemistry, physics, mathematics, biology, engineering, applied physics, chemical engineering, mechanical engineering, civil, and electricity. Its main focus is to explore the key relation between the structure, properties and application of matter. Therefore, it is one of the broadest and most active areas in chemical engineering, involving the discovery, evaluation and manipulation of useful material properties of different substances. To date, materials science has been expanding the array of materials that have unique characteristics and are useful for the development and fabrication of desirable, imaginative, and revolutionary new products. Related research has been contributing to great progress towards a sustainable future based on clean energy generation, through the development of ethanol production using syngas fermentation, transmission and distribution, the storage of electrical and chemical energy, energy efficiency, and better energy management systems. These advances aim to fulfill the widescale growing demand for energy in both developed and developing countries. Clean energy policy is also associated with the concerns about the detrimental effects of fossil fuels on the environment. Such environmental concerns have been at the forefront of limiting technological advances in various industrial sectors, prompting the intensive utilization of membrane filters, sensors and catalysts. In addition to the climate change associated with gas emissions from automobiles and factories, access to clean water, consumption of raw materials in the refining and separation processes of fossil fuels, and waste management have become important environmental issues, which scientists and engineers are actively trying to solve for present-day and future life. Innovative biocompatible materials, for instance, have improved the quality of life and lengthened people’s life spans. Chemical engineers have been at the forefront of these advances, creating applicable materials in the fields of biochemistry, thermodynamics and supercritical, nanomaterials and nanotechnology, chemical engineering management, separation and purification, renewable energy, water and waste treatment, food technology and pharmaceuticals, catalysts, chemical reactions, and engineering process systems. To address the abovementioned issues, the 1st International Symposium of Indonesian Chemical Engineering 2018 (ISIChem), with the main theme of “Chemical Engineering,” was held from October 4–6, 2018, at Kyriad Bumiminang Hotel, Padang, Sumatra Barat, Indonesia. The symposium, which was organized by Asosiasi Pendidikan Tinggi Teknik Kimia Indonesia (APTEKIM), facilitated researchers, academics and industry practitioners to present and discuss their research in scientific forums in the field of chemical engineering and to share their knowledge. In the symposium, twenty papers from various countries across the globe, including Japan, Libya, Taiwan, Malaysia and Indonesia, were presented. This Insight discusses the latest advances in materials science, which may boost the transition to a more sustainable environment and energy systems. In this issue of the International Journal of Technology, we provide coverage of the 1st International Symposium of Indonesian Chemical Engineering 2018 (ISIChem). At the symposium, the participants updated the current trends in new materials and approaches to the reuse of energy and waste, providing a space for discussion focusing on the methodology, technology, and empirical work of tropical renewable energy. Publishing information on the conference via traditional printed media, however, takes time and, for several reasons, the discussion presented might remain unknown to a wider audience. In this current special issue of the International Journal of Technology, we would therefore like to present the discussions in the form of research papers, thereby making them available to a wider readership. We are pleased to present 20 papers and, through the availability of the published materials, enrich and extend the ISIChem symposium reports.

NOx, a generic term for nitrogen oxides, is an air pollutant that can causes damage to the ozone layer, and produces greenhouse effects, acid rain and photochemical smog. It is mainly produced by diesel engine exhaust due to the reaction between nitrogen and oxygen, especially at elevated temperatures. NOx needs to be reduced from flue gas in order to fulfil environment regulations due to its hazardous nature. This study aims to remove NOx from air through absorption using a mixture of H2O2 and HNO3 solutions as an absorbent in the membrane contactors. In the experiment, the feed gas and the absorbent were flowed in the shell side and the lumen fibers, respectively. The flow rates of absorbent and feed gas, as well as the fiber number the membrane contactor, greatly influence the efficiency of NOx removal, mass transfer coefficients and fluxes. The highest values of NOx removal efficiency, mass transfer coefficient and flux achieved in the study were 47%, 8.7×10-5 cm.sec-1, and 3.1×10-5 mmole.cm-2.sec-1, respectively.

The 15th International Conference on Quality in Research (QiR) was held in Nusa Dua, Bali, Indonesia on July 24–27, 2017. The main theme was “Science, Technology and Innovation for Sustainable World.” This third book of special edition of International Journal of Technology (IJTech) present 18 papers in the research areas of chemical and metallurgy & materials engineering. The International Symposium on Chemical Engineering, QiR, covered various topics such as renewable energy business and economics, biomass conversion technologies, modeling and simulation, advanced thermal and chemical processes, waste to energy, advanced biofuel technology, catalysts, composites, photocatalysis, and adsorption. We have selected 10 papers from the 80 submitted for publication in the IJTech. The International Symposium on Materials and Metallurgy, QiR, covered topics such as carbon, graphene, oxides, nanocomposites, mesostructured materials, advanced superconducting, electrochemical water splitting, extraction, hydrometallurgy, and energy storage devices. We selected 8 papers from the 111 fullpapers for publication in the IJTech. The eighteen papers, from both symposia, are summarized below.

The aim of this study is to evaluate the effects of absorbent flow rate on CO2 absorption through a super hydrophobic hollow fiber contactor. The absorbent used in this study was a physical absorbent, namely a polyethyleneglycol-300 (PEG-300) solution. Meanwhile, the feed gases used in the experiments were pure CO2 and a mixture of 30% CO2 and 70% CH4. Gas absorption using a physical absorbent provides various benefits; for example, it can produce sufficiently high selectivity towards CO2 and it is less corrosive than chemical solvents. Three super hydrophobic hollow fiber contactors, each 6 cm in diameter and 25 cm in lengthconsist of 1000, 3000 and 5000 fibers, respectively, were used in this study. The type ofsuper hydrophobic fiber membrane used was polypropylene-based, with an outer and inner diameter of about 525 and 235 µm, respectively. During the experiments, the absorbent was flowed through the lumen fibers, whilst the feed gas flowed through the shell side of the membrane contactors. The experimental results showed that the mass transfer coefficient, the flux, and the absorption efficiency increased, but the CO2 loading decreased, with increasing absorbent flow rate in the membrane contactor. Meanwhile, it was found that an increase in the number of fibers in the membrane contactor, in general, will increase the absorption efficiency and the CO2 loading, but will decrease the overall mass transfer coefficient and the flux.

In the plasma electrolysis process, hydrogen generation around the cathode is affected by the amount of evaporation energy. Utilizing a veil, minimizing the cooling in the liquid phase, and maximizing the cooling in the gas phase become important parameters to improve the process efficiency of hydrogen production. This research aims to obtain an optimum high-efficiency electrolysis plasma reactor based on decreased energy consumption and increased hydrogen gas production. The research method varied the NaOH concentration, voltage, veil length, cathode depth, and the volume of the methanol additive. In characterizing the current and voltage, as the concentration increases, the voltage needed to form the plasma will decrease. As the concentration and voltage increase, the rate of production, hydrogen content percentage, and the hydrogen ratio also increase, while the energy consumption decreases. The optimum condition, based on variations of veil length, is 5 cm when the depth of the cathode is 1 cm below the surface of the solution. Improving the efficiency of the hydrogen production process can be done by adding methanol. The best result was achieved using 15% volumes of methanol additive in 0.01 M NaOH, and higher hydrogen-ratio plasma-electrolysis results were found in comparison with Faraday electrolysis: the hydrogen ratio was 151.88 mol/mol, the lowest energy consumption was 0.89 kJ/mmol, and the highest hydrogen production rate was 31.45 mmol/min. The results show that this method can produce hydrogen 152 times more than Faraday electrolysis.

Innovation has a central role in technology development. It is produced everywhere and enriched by local wisdom for problem solving in particular regions to further increase human wellbeing. Technology development thus becomes a dynamic system of relationships among various stakeholders, and it requires a collaborative and mutual partnership.Technology partnerships become a network model that is formed by stakeholders who share linked knowledge, activities, and resources, which lead to future strategic options and alternative product solutions that are efficient, effective, and sustainable. Technology results from inventors and researchers in various laboratories and companies translating ideas into prototypes, which can then serve various needs and purposes through transformation into value added products and/or projects. Technology transfer is conducted firstly via provider collaboration and secondly to customers. Both the governments and private investors that provide financial support to fund technology development and transfer make significant contributions by supporting development strategies and policies as well as creating sufficient market incentives.

This study aims to evaluate the effectiveness of a polypropylene hollow fiber membrane contactor in removing dissolved ammonia in wastewater using sulfuric acid solution as an absorbent. In the ammonia removal experiments, wastewater and absorbent solutions flowed through the shell side and the lumen side of the contactor, respectively. The pH of wastewater, rate of circulation and ammonia initial concentration were operating variables which influenced the efficiency of the removal process. The efficiency of ammonia removal increases with the wastewater pH level when it is at the same circulation rate and time. In addition, the increase in the circulation rate of the wastewater will increase the efficiency of ammonia removal and the overall mass transfer coefficient. Meanwhile, the efficiency of ammonia removal and the overall mass transfer coefficient decreased with initial ammonia concentration in the wastewater solution.

The study has been conducted to evaluate the effectiveness of the natural solvent from noni fruit for CO2 gas absorption from CH4 through hollow fiber membrane gas-liquid contactors. The solvent was made of 100 grams noni fruit per liter of water. In experiments, the solvent flowed to the shell side of the contactor, while the gas mixture flowed to the lumen fiber. The experimental results showed that mass transfer coefficients in the contactors increased with increasing liquid flow rate and decreasing number of fibers in the contactors. Mass transfer correlation indicated that the mass transfer in the contactor was dominated by turbulent flow. Hydrodynamics analysis of the contactors showed that at the same Reynolds number pressure drops increased with increasing packing density due to an increase in friction between fibers and water. The friction factor ratio data revealed that the fiber surface did not behave like a smooth pipe within the range of velocities in the experiments. Based on QI and Cussler coefficients, chemical absorption occurred during experiments, which might be indicated by the appearance of new compounds in the chemical analysis of the aqueous extract from noni fruit after absorption.