bluuebunny/crossref_metadata_2025 huggingface dataset:
First SOLPS-ITER predictions of the impact of cross-field drifts on divertor and scrape-off layer conditions in double-null configuration of STEP
Authors: Karhunen J. , Henderson S.S. , Järvinen A. , Moulton D. , Newton S. , Osawa R.T.
Published: July 2024

Introduction of cross-field drifts in SOLPS-ITER simulations of connected double-null plasmas in STEP with the ion

∇
B
×
B

drift towards the upper divertors was found to enhance the detachment of the inner divertors with decreased target densities and ion and heat fluxes, while simultaneously complicating the access to detachment in the outer lower divertor by increasing the target temperature and heat loads to levels above the engineering limits. The

∇
B
×
B

drift was observed to significantly affect the radial heat transport between the core and the scrape-off layer (SOL), altering the poloidal temperature and pressure profiles and, consequently, the poloidal conductive and convective heat transport in the SOL. As a result, up-down asymmetries of 52:48 and 58:42 biased towards the outer lower and upper inner divertors, respectively, were observed to arise in the unmitigated power entering the divertor regions, breaking the up-down symmetry seen in simulations without the drift terms and contradicting with earlier experimental observations on the low-field side. Moreover, the upstream electron density was found to decrease noticeably in the core and separatrix regions following the activation of the drifts due to an increased share of the neutrals arriving from D2 injections near the upper and lower X-points ionizing already in the private flux regions.
Independent-oscillator model and the quantum Langevin equation for an oscillator: a review
Authors: Ghosh Aritra , Bandyopadhyay Malay , Dattagupta Sushanta , Gupta Shamik
Published: July 2024

This review provides a brief and quick introduction to the quantum Langevin equation for an oscillator, while focusing on the steady-state thermodynamic aspects. A derivation of the quantum Langevin equation is carefully outlined based on the microscopic model of the heat bath as a collection of a large number of independent quantum oscillators, the so-called independent-oscillator model. This is followed by a discussion on the relevant ‘weak-coupling’ limit. In the steady state, we analyze the quantum counterpart of energy equipartition theorem which has generated a considerable amount of interest in recent literature. The free energy, entropy, specific heat, and third law of thermodynamics are discussed for one-dimensional quantum Brownian motion in a harmonic well. Following this, we explore some aspects of dissipative diamagnetism in the context of quantum Brownian oscillators, emphasizing upon the role of confining potentials and also upon the environment-induced classical-quantum crossover. We discuss situations where the system-bath coupling is via the momentum variables by focusing on a gauge-invariant model of momentum-momentum coupling in the presence of a vector potential; for this problem, we derive the quantum Langevin equation and discuss quantum thermodynamic functions. Finally, the topic of fluctuation theorems is discussed (albeit, briefly) in the context of classical and quantum cyclotron motion of a particle coupled to a heat bath.
Design of a bipedal robot for water running based on a six-linkage mechanism inspired by basilisk lizards
Authors: Zhao Jingfu , Han Jiaxu , Ju Wenjie , Zhang Wenjie , Hou Zhenmin , Bian Chenya , Kang Rongjie , Dai Jiansheng , Song Zhibin
Published: July 2024

Legged robots have received widespread attention in academia and engineering owing to their excellent terrain adaptability. However, most legged robots can only adapt to high-hardness environments instead of flexible environments. Expanding the motion range of legged robots to water is a promising but challenging work. Inspired by basilisk lizards which can run on water surfaces by feet, this paper proposes a bipedal robot for water running by hydrodynamics instead of buoyancy. According to the motion parameters of the basilisk lizard during water running, a single-degree of freedom bipedal mechanism is proposed to reproduce the motion trajectory of the feet of the basilisk lizard. Scale optimization is conducted by a particle swarm optimization algorithm to determine the geometrical parameters of the mechanism. The effects of motion frequency and foot area on mechanism performance are studied and the optimal solutions are determined by the maximum single-cycle lift impulse through numerical calculations. A bipedal water running robot prototype was fabricated, and the experimental results show that the prototype can generate enough support for the robot running on the water by providing a maximum lift of 2.4 times its weight (160 g) and reaching a horizontal forward speed range of 0.3–0.8 m s−1, compared with the basilisk lizard weighs 2–200 g, generates a lift impulse that is 111%–225% of its body weight, and moves at a speed of 1.3 ± 0.1 m s−1.
Water budget-based evapotranspiration product captures natural and human-caused variability
Authors: Goswami Shubham , Rajendra Ternikar Chirag , Kandala Rajsekhar , Pillai Netra S , Kumar Yadav Vivek , Abhishek  , Joseph Jisha , Ghosh Subimal , Dutt Vishwakarma Bramha
Published: July 2024

Evapotranspiration (ET) is one of the most important yet highly uncertain components of the water cycle. Available modeled ET products do not necessarily agree with each other at various spatiotemporal scales, either due to limitations on input data and/or due to model assumptions and simplifications. Therefore, using the water budget equation to estimate ET has gained attention. However, numerous water budget combinations with large uncertainties are available, which increases ambiguity in choosing the best ET estimate. Here, the Kalman filter is employed to ingest 96 water budget-based ET estimates, and produce a global ET product with uncertainty

<

2

 mm month−1, and capture the general spatiotemporal pattern of ET and the inter-annual variability over all continents. Since the water budget includes storage changes due to human interventions, our ET estimates are superior over regions with strong irrigation signals, such as the Ganges basin. We verify our claim by using a modified variable infiltration capacity model that also simulates irrigation activities. Our ET estimates have a global mean positive trend of

0.18

±

0.02

mm yr−1 with larger regional variations, which we discuss.
Heat extremes linearly shift with global warming, with frequency doubling per decade since 1979
Authors: Vautard Robert , Barnes Clair , Philip Sjoukje , Kew Sarah , Pinto Izidine , Otto Friederieke E L
Published: July 2024

Heat extremes have been increasing both in frequency and in intensity in most land regions of the world, and this increase has been attributed to human activities. In the last decade, many outstanding and record shattering heat extremes have occurred worldwide, triggering fears of a nonlinear behaviour or an ‘acceleration’ in the development of heat conditions, considering the warming level when the event occurred. Here we show that the evolution of yearly temperature maxima, with return periods (RPs) above 10 years, consistently shifts with global temperatures and does not significantly depart from this behaviour in recent years or decades when considered globally or at the scale of continents. This result is obtained by using a classical statistical event attribution technique, where the assumption that the distribution of block-maxima extremes linearly shifts with global warming is tested across years and world land regions. However, the pace of frequency change is large, with the probability of heat extremes exponentially rising and nearly doubling every decade since 1979, particularly when considering events with a RP of about 10–50 years in 2000. This makes the climate of a decade ago unrepresentative of today’s climate. Our results overall mean that we do not expect events like the recent outstanding extremes to undergo nonlinear changes, despite fast changes. They also show that assumptions underlying attribution techniques used in many recent studies are consistent with recent temperature trends.
Management of functional constipation-associated halitosis: a retrospective study
Authors: Qian (钱孝先) Xiao Xian
Published: July 2024

The features of functional constipation (FC)-associated halitosis were identified in the author’s previous report. In this report, the author aimed to further investigate its treatment and efficacy. This retrospective study reviewed 100 FC patients, including 82 (82%) halitosis patients and 18 (18%) non-halitosis patients. They underwent the organoleptic test (OLT) to diagnose halitosis, and the organoleptic score (OLS) (0–5) was used to evaluated halitosis severity. The Cleveland Clinical Constipation Score (CCCS) (0–30) was used to evaluate FC severity. Patients were treated with the laxative polyethylene glycol electrolyte powder (PGEP) for four weeks. These tests were performed before and after treatment. The author found that, before treatment, the CCCS was 20.00 (18.00–23.00) for all patients, 21.00 (19.00–24.00) for halitosis patients, and 18.00 (17.00–18.25) for non-halitosis patients. A significant difference was observed between halitosis patients and non-halitosis patients (P < 0.001). The OLS for halitosis patients was 3.00 (3.00–4.00). A positive correlation (r = 0.814, 95% CI: 0.732–0.872, P < 0.001) was found between OLS and CCCS. A CCCS ⩾18 predicted over 50% probability of halitosis. After treatment, the CCCS significantly decreased to 11.50 (6.00–14.75) (P < 0.001), and OLS significantly decreased to 1.00 (0.00–2.00) (P < 0.001). A positive correlation (r = 0.770, 95% CI: 0.673–0.841, P < 0.001) persisted between OLS and CCCS. A pre-treatment CCCS ⩾21 predicted over 50% probability of post-treatment halitosis, while a post-treatment CCCS ⩾12 predicted over 50% probability of post-treatment halitosis. The author concludes that the severity of FC parallels the severity of FC-associated halitosis, and can predict the probability of halitosis. Laxative treatment with PGEP is effective in improving FC-associated halitosis.
First-principles calculation of monolayer PdSe2 with Se and Pd vacancy and its effect on quantum capacitance
Authors: Paz K A , Villagracia A R , David M Y
Published: July 2024

The emergence of 2-D materials such as graphene has caught the attention of the scientific community. 2-D materials have a higher surface area per unit mass, which is ideal for electrodes. Another popular material among researchers is the monolayer palladium diselenide or PdSe2, a semiconductor with a tunable bandgap energy. Since there are fewer states in the fermi level of PdSe2, the quantization effect is more prevalent, hence, it would most likely draw its capacitance from its electronic configuration. In this study, the electronic properties such as band structure, density of states, and quantum capacitance of pristine monolayer PdSe2, PdSe2 with Se, and Pd vacancy were calculated based on density functional theory via Quantum Espresso. The formation energies of all systems were energetically favourable. The system with Se vacancy has the highest formation energy with a value of -3.47 eV. The density of states of all systems were observed to have a local minima at the fermi level. More occupiable states around the valence band were observed for the systems with vacancy. Bader charge analysis showed a notable decrease of charge in Se atoms near the Pd vacancy, while the Pd atoms in the Se vacated system showed stronger charge transfer between Pd and another Se atom. The quantum capacitance and surface charge values were calculated using the density of states. Higher surface charge values at the negative voltage were observed for the systems with induced vacancies. Based on the results, the systems with vacancies have improved the quantum capacitance and surface charge at the negative potential.
Systematic literature review of software tools for modeling heat transfer in phase change materials for building applications
Authors: Vanaga R , Narbuts J , Zundāns Z , Gušča J
Published: July 2024

New buildings in the European Union must attain nearly zero-energy status, emphasizing minimal energy consumption, partly met by on-site or nearby renewable sources. However, the fluctuating nature of on-site renewables poses a challenge, necessitating effective energy storage solutions. Addressing this, the use of phase change materials (PCMs) in building envelopes emerges as a promising trend. PCMs efficiently store excess thermal energy during abundance and release it when renewable generation falls short, ensuring a consistent energy supply. Introducing novel building components is time-intensive, with on-site testing demanding substantial resources. Numerical studies offer an efficient alternative, making modeling tools crucial. These tools facilitate exploration of design concepts under diverse conditions, allowing iterative refinement and optimization. This paper conducts a systematic literature review evaluating five prominent software programs—COMSOL, ANSYS, MATLAB, EnergyPlus, and TRNSYS—designed for modeling heat transfer within PCMs for building applications. In closer detail paper explores the use of ANSYS for heat transfer analysis for phase change materials.
Performance analysis of ground source heat pump systems for constant temperature and humidity air conditioning in industrial buildings: a case study
Authors: Du S S , Cui Y , Sun Q H , Deng Y , Zhang X W
Published: July 2024

The ground source heat pump (GSHP) system has gained widespread popularity for its provision of efficient and environmentally sustainable cooling and heating solutions for buildings. While the performance of GSHP systems has raised significant concerns, research predominantly focuses on residential and office buildings, leaving a gap in understanding their applicability in industrial settings with constant temperature and humidity air conditioning needs. This study aims to address this gap by evaluating the performance of a hybrid ground source heat pump (HGSHP) system implemented within a cigarette factory located in the hot summer and cold winter (HSCW) of China. Through a comprehensive analysis of operational data and long-term monitoring under three cooling conditions, essential parameters including water temperature characteristics, indoor temperature and humidity, system efficiency, power consumption, and soil temperature distribution were examined. The findings revealed that the weighted average coefficient of performance (COP) of the heat pumps (COPhp) and the whole system (COPsys) was decreased from 5.05 to 4.32 and 3.32 to 2.89, respectively. A positive correlation was observed between low cooling load high energy consumption, and low COP. The inlet temperature of the condenser exhibited a declining trend, which was attributed to the intermittent operation of condensation heat recovery. Furthermore, a comprehensive analysis of indoor temperature and humidity distribution within the controlled room was presented and found that almost all the rooms serviced by this system meet the specified design requirements. This research contributes to an enhanced understanding of the viability of HGSHP systems in industrial settings and provides valuable references for improving their energy efficiency and overall performance.
Development of zwitterion-functionalized graphene oxide/polyethersulfone nanocomposite membrane and fouling evaluation using solutes of varying charges
Authors: Soh C.Z. , Chang Z.H. , Sum J.Y. , Yeap S.P , Chai P.V , Jawad Z.A.
Published: July 2024

This study explores the functionalization of polyethersulfone (PES) ultrafiltration (UF) membranes using zwitterion-functionalized graphene oxide (GO) and assesses their interactions with solutes of different charges, both neutral and anionic. Initially, PES nanocomposite membranes were synthesized, incorporating varying dosages (ranging from 0-1 % (w/w)) of glycine-functionalized graphene oxide (Gly/GO) and diglycine-functionalized graphene oxide (diGly/GO) through a direct blending method. The physicochemical properties, including hydrophilicity, surface morphology, and porosity of these membranes were characterized using sessile-drop contact angle, tabletop scanning electron microscopy (SEM), and gravimetric methods, respectively. Subsequently, the antifouling performance of these synthesized membranes was assessed by exposing them to a solution containing sucrose as a neutral model foulant and humic acid as an anionic foulant. The incorporation of zwitterion-functionalized graphene oxide nanoparticles improved the surface wettability of the nanocomposite membrane, enhancing its resistance to sucrose fouling. This was supported by a reduction in flux declination ratio (e.g., 40.6 % for pristine PES, 29.7 % for 1.0 % (w/w) Gly/GO PES, and 33.1 % for 1.0 % (w/w) diGly/GO PES) and an increase in flux recovery ratio (67.2 % for pristine PES, 79.7 % for 1.0 % (w/w) Gly/GO PES, and 80.0% for 1.0 % (w/w) diGly/GO PES). The improvement in antifouling characteristics is attributed to the formation of a hydration layer on the membrane surface, which inhibits sucrose deposition. However, zwitterion-functionalized PES nanocomposite membranes displayed a higher affinity for anionic humic acid, resulting in a substantial flux decline and a lower flux recovery ratio. Overall, this research provides insights into the roles of surface wettability and the charge interactions between solutes and the membrane surface, both of which are crucial factors in determining fouling severity and the restorability of spent membranes.
Evaluating Lean Combustion Cycle Stability and Emissions in Spark Ignition Engines with Gasoline, Ethanol, and Methanol Blends
Authors: Agama A A , Sugiarto B , Mokhtar  , Kurniawan A , Auzani A S , Wisnugraha M A , Rahatwan Z B , Prasetyo D
Published: July 2024

Fuels for vehicles account for a large portion of the world’s total energy demand, which in turn leads to increased carbon emissions. Ethanol and methanol are a fuel with a simple carbon chain and OH- bonds. It has similar properties to gasoline, and ethanol can be made from the fermentation of plant carbohydrates, called bioethanol. The advantage of using bioethanol is that it contributes to carbon neutrality. This paper will investigate the use of three manually blended gasoline ethanol and methanol (GEM) fuels in a spark ignition engine to address cycle-to-cycle variation (CCV), knock potential, and emissions with lean blend conditions. In the experiments conducted, the air-fuel ratio was conditioned lean by utilizing an electronic control unit to adjust the injector spray duration. This experiment provides results that there is a potential for mild knocking on the use of alcohol fuel with lean fuel mixture conditions at engine speed 4000 RPM, while at engine speed 6000 RPM and 8000 RPM the use of GEM tends to be stable, but in the CCV results the increase in COV (coefficient of variation) value using GEM fuel tends to be more sloping, especially with the addition of more methanol. Emission results from the use of GEM produce top emission CO2 value obtained by the E5M15 mixture at λ=1.2 and an engine speed of 8000 RPM, with a value of 13.75% and then peak CO2 emissions at a value of λ = 1.2 whereas in the use of pure gasoline peak CO2 is at a value of λ = 1.1.
CFD simulation for CO2 separation using diamond-structured thermally rearranged (TR) polymer membrane: Effect of CO2 feed concentration, feed pressure and temperature
Authors: Toh W Y , Lai L S , Tay W H , Yeap S P , Jawad Z A , Markandan K
Published: July 2024

CO2 separation in natural gas purification is important in improving the properties of natural gas such as energy content, volume and corrosivity. Membrane separation using TR-450 polymer membrane is a potential approach to remove CO2 from natural gas efficiently. The study of CO2/CH4 binary gas mixture separation was simulated using a thermally-rearranged (TR) HAB- 6FDA membrane at 450 °C with a partial part of Schwarz Diamond structure because it exhibits advanced mechanical properties with low stiffness for relatively high strength. TR-450 membrane exhibits excellent separation performance that has the potential to exceed the Robeson plot 1991. Computational fluid dynamics (CFD) was used to simulate the fluid behavior within the geometry created using CAD software. The effect of feed pressure, temperature and CO2 feed concentration on the separation performance of TR-450 membrane was also studied. The results indicated that an increase in feed pressure leads to a decrease in CO2 recovery, hence the lower separation performance. It was also found that increasing the feed temperature leads to an increase in CO2 recovery. Concerning the concentration of CO2 in the feed, elevated levels impact the performance of membrane separation. The enhanced membrane separation performance demonstrated by the TR-450 membrane under various conditions underscores the necessity for additional investigation to unveil its potential in industrial gas separation applications.
Analysing type of plants for reducing noise pollution in climate change adaptation
Authors: Hashim W , Jamaludin S M , Mohamed R M A R , Gunasekaran S S , Thabit R , Gohel H
Published: July 2024

The noisier a region or city is, the faster the rate of global warming. Noise is not a substance. However, most sources of carbon dioxide and other greenhouse gases are also sources of noise; for example, busy highways in cities can occasionally see as many as 100 cars per hour. Planting trees to mitigate noise pollution has been identified as one of the most sustainable methods to employ, since plants may function as a buffer and absorb sounds. Several plant species were chosen to assess noise absorption based on parameters such as leaf thickness, breadth, surface area, and length. The initial goal of this study is to estimate the noise absorption on the selected flora native to the Malaysian environment, where the noise was measured using an in-house developed impedance tube to discover the effective acoustic characteristics of leaves. The investigation was then carried on by assessing the data on the correlation coefficient parameter in order to determine the link between noise absorption and leaf features. Because of the freshness and perishability of the materials, measurements were repeated twice. Only 100% and 50% vegetation quantity size were measured for 10 sample species during the initial data collection. According to the findings, half of the leaves’ features were connected with noise absorption. This might be owing to the freshness state, which cannot be maintained for an extended period of time. To acquire a better value, the experiment was repeated within the permissible freshness time. The findings are as predicted, with the maximum noise absorption and features correlation at 100% plant density including twigs. When the vegetation amount is lowered to 50%, this will progressively diminish. The notion is confirmed by the fact that a tube packed with thicker samples absorbs more noise. The correlation study identifies that each leaf has its unique capacity for noise absorption dependent on its properties and freshness level.
Assessing the Environmental Impact of Empty Fruit Bunches for Electricity Generation in Malaysia: A Life Cycle Perspective
Authors: Sukhairul Zaman Nur Zaqira Izzati , Abbas Ahmad Rosly , Zainal Mohamad Fetri , Quek Alexandra , Wan Ata Wan Nur Syuhada , Mohd Yapandi Md Fauzan Kamal , Ibrahim Zul Fadli
Published: July 2024

Empty fruit bunches (EFB) constitute a significant residual byproduct of the palm oil mill industry in Malaysia, representing approximately 22% of the weight of every fresh fruit bunch. This study aims to evaluate the environmental impacts associated with electricity generation utilizing EFB as a primary fuel through a cradle – to – grave life cycle assessment (LCA) approach. The system boundary encompasses the power plant construction, fuel preparation, electricity generation and all transportation activities throughout its life cycle. The EFBs are sourced from seven palm mills situated within a 50-kilometer radius of the plant. SimaPro 9.4.02 software integrated with Ecoinvent 3.8 database was employed to quantify the magnitudes of significant environmental indicators, such as global warming potential (GWP), ozone depletion potential (ODP), acidification potential (AP), eutrophication potential (EP), and photochemical oxidant creation potential (POCP), based on a functional unit of 1 kWh of electricity produced. The emission rate for the biomass plant stands at – 5.31 kgCO2eq/kWh, signifying a net carbon sink. The electricity generation process accounts for a substantial 96.48% of the total CO2eq/kWh emissions, thus bearing the greatest environmental burden. The construction phase of the biomass plant contributes approximately 3.06% of the total emissions, while the EFB transportation to the power plant represents a minor 0.19% of the overall emissions. A sensitivity analysis was conducted to evaluate the plant’s efficiency across fiscal years 2018 to 2021 and its corresponding global warming impacts. In 2021, the plant’s operations resulted in the most significant carbon avoidance, given the combustion of a high volume of EFB (188 kilotons) to produce 49.3GWh of electricity. The findings from this study serve as a valuable benchmark for evaluating emissions in the context of the empty fruit bunch-based plant in Peninsular Malaysia, hence offering profound insights into the environmental sustainability of the palm oil industry.
Multi-period optimization of water planning for a sustainable agriculture: carbon footprint and water footprint assessment
Authors: Lahlou F , Al-Ansari T
Published: July 2024

The State of Qatar has undergone significant changes impacting water resources in recent years, with rapid population growth being a significant factor. The government has implemented several policies and initiatives to manage water resources effectively, including introducing a water conservation strategy investing in desalination plants and wastewater treatment facilities. However, the expansion of the agricultural sector has driven up demand for water resources, placing additional pressure on limited supplies. Effective decision-making processes are crucial to sustainable water resource management, particularly in water-scarce countries, and multi-period optimization is an important tool for such decision-making. This study presents a five-year period for multi-period optimization of water planning in the agricultural sector to consider short-term and medium-term dynamics. The aim is to minimize the carbon footprint associated with agricultural water allocation, and assess water pollution using the Water Quality Index grey water footprint indicator. The water budget considered includes desalinated water, brackish groundwater, and treated sewage effluent, while the agricultural sector comprises dairy, egg and poultry, red meat production, outdoor farming, and indoor farming. Considering the water conservation importance in the State of Qatar, the three levels of water stress that were considered are 0%, 25% and a base scenario carbon footprint-based water stress. The latter is calculated such that the improved scenario’s carbon footprint is lower than that of the base scenario while keeping a safe annual water stress. Results show that it possible to reduce the water stress from an unsafe average to as little as 13.7%. Similarly, the water pollution estimated using the grey water footprint method is significantly lower compared to the base scenario.
CO2 emission mitigation of a hybrid photovoltaic and cogeneration system in computer hardware manufacturing industry: A case study in Thailand
Authors: Manirampa D , Chaiwiwatworakul P
Published: July 2024

In the wake of COP26 and the growing urgency of addressing climate change, achieving carbon neutrality by 2050 has become a central global objective. This imperative extends to industries like computer hardware manufacturing, which are now actively pursuing decarbonization strategies through the strategic adoption of renewable energy sources and energy efficiency enhancements. This research paper assessed the CO2 emission mitigation potential of a hybrid system of photovoltaic (PV) roof and cogeneration where a large factory of computer hardware manufacturing in tropical Thailand was selected as a study site. On one hand, a one-Megawatt photovoltaic system was installed over the roof of the production building to generate electricity from solar radiation to serve the building. On the other hand, a twenty-four-Megawatt cogeneration system of gas engines as the prime mover was used to supply power to meet the building’s electricity demand. Waste heat from the gas engine was used by the absorption chiller to generate chilled water for cooling inside the building. Based on the system equipment specifications, the annual simulation using Thailand’s solar radiation showed that the installed photovoltaic system could generate electricity of 1,412.4 MWhelec/year while the implementation of the absorption chillers for cooling helped to reduce the electrical energy consumed by the traditional electric chiller by 10,211.4 MWhelec/year. In our study case where the CO2 emission of the grid power was 0.4758 kgCO2/kWhelec in the year 2022 and was reduced to 0.350 kgCO2/kWhelec in the year 2050, the total CO2 emission mitigation from the hybrid photovoltaic and cogeneration system with the genset efficiency of 50% and the waste heat recovery of 60% could reduce approximately 207,388.5TonCO2 for over 20 years as compared to the scenario where the grid electricity alone powered the building. These findings underscored the critical role of the proposed hybrid system in addressing the climate crisis and exemplified how the industry could make meaningful strides toward more environmental sustainability.
Mycelium-metal hybrids: Exploring fabrication and application for reconfigurable design structures
Authors: Soh E , Teoh J H , Mathialagan M , Peh R J H , Yong W N , Ranner V , Le Ferrand H
Published: July 2024

Mycelium-bound composites (MBCs) are materials grown by fungi onto lignocellulosic substrates. MBCs are a low-cost, lightweight, valorised biomass with promising properties concerning acoustics, heat insulation and fire resistance, among others. These properties make MBCs interesting as a sustainable alternative to currently existing fossil-fuel-derived products. However, MBCs lack properties such as mechanical strength or other functional properties like electrical conductivity which could widen their range of applications. In this work, the mycelium from Pleurotus ostreatus is grown in presence of metals. First, a coating strategy is developed to grow the fungus on aluminium, copper, and stainless-steel surfaces. The coating is made of agar and cornstarch to provide nutrients for the fungus to grow. It is found that the mycelium can grow on all surfaces, even on anti-bacterial copper surface. Secondly, magnetic MBCs with 3D shapes are fabricated for making potential reconfigurable structures. For these composites, the fungus is exposed to lignocellulosic substrate and rare earth magnets. Using 3D printing to create 3D moulds to grow the composite, and by strategically placing the magnet, several structures are made. This approach is interesting for the future design and fabrication of reconfigurable panels for room partition, building thermal or insulation, or to replace plastics in toy products, among others.
Elephant skin-inspired mycelium tiles for thermal regulation of buildings
Authors: Soh E , Loh N Y J , Teoh J H , Jain A , Le Ferrand H
Published: July 2024

Of all types of ecosystems, cities are the most polluting and this pollution affects more than 50% of the global population. One main cause for this pollution is related to the energy used to heat or cool down buildings. Currently, only 15% of households in Southeast Asia have an air conditioner, but this number is expected to rise, leading to an increase in demand in energy consumption, electricity and CO2 emissions which could further worsen global pollution and climate change. There is therefore an urgent need to find alternative solutions to cool buildings and regulate their temperatures. In this paper, inspiration is taken from elephants who live in very hot climates. Elephants can cool themselves thanks to the wrinkles on their skin that can limit heat gain, dissipate energy by evaporative cooling and store water. To emulate elephants’ cooling, tiles with elephant skin-inspired surface texture are designed. Computational simulations are performed to evaluate the effect of local shading due to the texture. Experimental tiles are produced using a biodegradable and natural material grown by a fungus, Pleurotus Ostreatus. These tiles are mycelium-bound composites (MBCs) where the fungus grew on bamboo microfibers, developing an interconnected web of cells called the mycelium that binds the microfibers together. The thermal properties of the tiles were measured for heating and cooling on the textured and flat side. The results show the tiles have anisotropic properties with a significant improvement by 25% in the cooling of the textured side over the flat side. In simulated rain conditions, the cooling is further improved by 42% as compared to dry conditions. The elephant-mycelium tiles are therefore promising for thermal regulation of building in Southeast Asia environments.
Development of thermal insulation material using coconut and kenaf fiber for heat recovery enhancement
Authors: Shah R E , Saadon S , Rahman N K , Abdellatif N
Published: July 2024

In line with the world’s Sustainable Development Goals (SDG), Malaysia aims to have a clean future energy. The main problem facing the energy revolution is the low conversion efficiency of low-grade heat to useful energy. During the process, a significant fraction of thermal energy is generally lost to the environment as waste heat. Waste heat accounts for 20-50% of industrial energy use, with Southeast Asia processing 40 million tonnes of oil equivalent. Heat losses especially in engines can reduce efficiency, leading to extensive studies to reduce heat loss and improve thermal performance. Heat recovery systems are being studied to recover lower-grade energy, but to the extent of the authors’ knowledge, the majority of them are not economically effective for low temperature waste heat. Therefore, the objectives of this study are to develop low thermal conductivity material for thermal insulators based on natural fibre and investigate their impact on thermal performance. The natural fibre-based materials that were chosen in this study are coconut husk and kenaf fibre due to their supposedly low thermal conductivity level and availability in the Southeast Asia region. The specimens were prepared using two different methods; the first two specimens using needle felting method and for the other two specimens epoxy resin was reinforced to bind the material together to become a polymer. The results revealed that coconut husk fibre reinforced with resin has the lowest thermal conductivity value among the four specimens with 0.0410 W/m.K and the lowest overall heat transfer coefficient of 2.73 W/m2.K, making it a possible thermal insulator to be proposed for heat recovery.
Framework design of recycling system for expired medicine and waste batteries in Chinese community
Authors: Zhang M R , Chong W T
Published: July 2024

Hazardous waste poses a significant threat to the environment. Improper disposal of hazardous waste generated from residents’ daily activities can substantially burden the environment. Expired medicine and waste batteries pose the most significant risks to Chinese residents regarding hazardous waste exposure. Approximately 15,000 tons of expired medicine and 3 million tons of waste batteries are generated annually, further exacerbating the environmental burden. Research on hazardous waste generated by residents’ daily lives has received significant attention in China. Most studies have concentrated on enhancing the structure of recycling equipment and conducting theoretical analyses of recycling strategies. However, further research is required to conduct a comprehensive design process study specifically tailored to the characteristics of the Chinese community. Based on the findings from a questionnaire survey conducted among Chinese residents, this survey showed that more than 90% of the participants intended to recycle used batteries and expired medications. However, it was observed that only 30% of the residents were currently engaged in voluntary sorting and recycling practices for these items. Given the prevailing circumstances, this study proposes a design framework to enhance recycling awareness among Chinese residents. The system design scheme is based on the design framework and includes the cooperation of residents and community workers. This recycling system scheme includes a recycling bin 3D model and a WeChat mini-program design. This recycling system facilitates the dissemination of scientific knowledge about hazardous waste through a WeChat mini-program. Moreover, implementing a user-point reward mechanism has proven effective in incentivizing resident participation in recycling activities. Building upon the comprehensive design framework, this study seamlessly integrates green design principles into the daily lives of Chinese residents.
Effects of the filter media pack configurations on the air filtration performance
Authors: Chong JJ , Poon HM
Published: July 2024

High efficiency particulate air (HEPA) filters are widely used in various industries to contain airborne contamination. The pressure drop of the filters is a crucial performance parameter when designing a HEPA filter as it is the resistance that the filter offers to the flow of air. Thus, it is critical to find the effect of each configuration and integrate an optimal setup for the filter to avoid high-pressure drops. Set against these backgrounds, this study aims to study the effect of different configurations on the total pressure drop of the filter, and to review how each configuration can affect each other using a commercial software ANSYS Fluent. The different filter media pack configurations and boundary conditions investigated here are including pleat shape (V-shaped and U-shaped), pleat density (1-7 pleat/cm), pleat height (1cm, 1.3cm), and inlet velocity (0.02-0.2 m/s) on the pressure drop of the filter. A two-dimensional geometrical model is developed, and then validated with respect to the data obtained from Lydall M3004-06 property sheet. Upon successful validation exercise, a series of parametric studies is conducted to numerically examine the impact of changing each configuration on the total pressure drop of the filter. Results show that an optimal pleat density is attained where the total pressure drop is minimized, i.e., 3 pleat/cm for V-shaped and 4 pleat/cm for U-shaped for inlet velocity of 0.02 m/s. At a constant inlet velocity, the U-shaped pleat has a lower pressure drop than the V-shaped pleat at low pleat densities, but a higher pressure drop at higher densities. This behaviour can be attributed to the balance between inertial and viscous resistance. Increasing the inlet velocity increases the total pressure drop for all pleat heights and decreases the optimal pleat density. This effect is less pronounced on the V-shaped pleat. Increasing the pleat height for the U-shaped pleat decreases the pressure drop and optimal pleat density but increases pressure drop in the viscous dominated region. Conversely, increasing the pleat height for the V-shaped pleat decreases the pressure drop for all pleat counts and only decreases the optimal pleat density at high velocity.
Seawater source heat pump system based on capillary heat exchanger for seepage in submarine tunnel: a case study
Authors: Zhang F J , Zhang L , Li C , Gao S J
Published: July 2024

The discharge of seepage water from undersea tunnel structures, often treated as wastewater, inherently carries a substantial reservoir of untapped low-grade thermal energy. Unfortunately, comprehensive investigations into harnessing this latent potential remain notably limited. This study introduced an innovative strategy through the design of an undersea tunnel seepage seawater source heat pump system. Distinguished by the integration of a capillary front-end heat exchanger, this system aimed to effectively exploit the frequently disregarded low-grade thermal energy present in the seepage water of undersea tunnel structures. The seawater seepage from the tunnel is transported to the car park at the tunnel entrance, and a seawater energy pool is constructed by storing seawater in its underground space. The use of capillary network placed in the energy pool in the front heat exchanger, water source heat pump units, circulating water pumps and fan coil end device composed of underground undersea tunnel seepage seawater source heat pump system for the building heating and cooling. Furthermore, a comparative assessment was conducted, contrasting this novel system with the traditional air-conditioning setup that utilizes chillers and gas boilers as cooling and heating sources. The aim was to evaluate its capacity for energy conservation and emission reduction. The findings from the study strongly affirmed the viability of the proposed seepage seawater source heat pump system within undersea tunnels. It boasted the potential to achieve annual savings of 53.55 tce, highlighting a noteworthy energy-saving rate of 21.2%. Concurrently, reductions in CO2, SO2, and particulate emissions amounted to 132.28 t/a, 1.07 t/a, and 0.54 t/a, respectively. This study not only stands as a reference for the strategic utilization of seepage seawater from undersea tunnel structures, prioritizing energy conservation and emission reduction, but also pioneers innovative approaches toward resource optimization and environmental sustainability, meeting the inherent needs of carbon peaking and carbon neutrality goals.
Enhancing efficiency in closed agricultural greenhouses: A data-driven predictive model for energy consumption
Authors: Ghiat Ikhlas , Al-Ansari Tareq
Published: July 2024

Predicting energy consumption in agricultural greenhouses is essential to effectively allocate resources, enhance plant growth, and minimize energy inefficiencies. Various factors affect the energy consumption inside the greenhouse including external climate conditions and internal microclimate. Proper understanding of these factors is crucial for maintaining an ideal growing environment and optimizing energy efficiency. This drives the need to investigate the interaction between these factors and greenhouse energy consumption, encompassing the energy needed for cooling and the supply of water and nutrients. This work aims at developing a dynamic model that predicts the total energy consumption of a closed agricultural greenhouse to improve microclimate control and energy efficiency. The study is conducted within a closed-loop agricultural greenhouse with no natural ventilation. Inside, the air is cooled and continuously circulated without being exchanged with ambient air through a heating, ventilation, and air conditioning (HVAC) system. The data-driven model encompasses external climate parameters such solar radiation, ambient temperature, and relative humidity; along with microclimate parameters such as internal temperature, humidity, and CO2 concentration to predict overall energy consumption. The study examines two machine learning models, deep neural networks (DNN) and extreme gradient boosting (XGBoost), for forecasting energy consumption, and assesses their performance using the coefficient of determination (R2), the root mean square error (RMSE), and the mean absolute error (MAE). Results reveal that the DNN model surpasses the XGBoost model, exhibiting a superior predictive performance with an R2 of 80.9%, RMSE of 171.1 kWh and MAE of 130.3 kWh. This study demonstrates its practicality in assisting with energy consumption analyses and identifying inefficient energy usage patterns within closed agricultural greenhouses.
Heat transfer simulation for re-design of tray dryer to reduce the energy consumption in the cocoa bean drying process
Authors: Dharma I A , Haikal M G Z , Ridlwan M , Dewanto S A , Rahman M A
Published: July 2024

The tray dryer for the cocoa bean drying process is a solution to overcome conventional drying methods that rely on solar heat. The tray dryer is expected to facilitate the cocoa farmers to dry cocoa beans because it is faster and does not depend on weather conditions. However, even though the current condition of the tray dryer can reduce the energy consumption of drying cocoa beans (from Gunung Kidul, Yogyakarta, Indonesia) compared to the solar heat method, it remains unknown whether the cocoa beans drying quality is good enough. Therefore, this research analyzed the heat transfer phenomena of the cocoa drying process using the computational simulation method to re-design the current tray dryer design so that the new design can fit the drying characteristic of the cocoa bean and reduce energy consumption. As a result, for the air velocity of 25.91 m/s and the ½ opening of the gas valve in 10 minutes, which is already at steady-state conditions, the temperature distribution in the existing tray dryer is not suitable with the characteristics of the cocoa beans drying process. The temperature can be increased by reducing the airflow velocity or increasing the heating value by opening the valve. However, with a new design, the temperature can be increased by up to 37.00% at a velocity of 25.91 m/s with a ½ gas valve opening. Furthermore, the new design can achieve the same conditions as the existing design by only using an opening for a 1/8 gas valve. Thus, using the new design, the tray dryer can achieve the drying characteristics of cocoa beans and reduce energy consumption.
Observation of inclusions and intra-granular ferrite evolutions at the HAZ of low-carbon steel with different thermal histories
Authors: Nguyen Hong Hai , Nam Nguyen Duong , Nhung Le Thi , Ha Minh-Tan , Pham Mai Khanh
Published: July 2024

This study investigated the formation and growth of intra-granular ferrite with inclusions (TiN, MnS) in the heat-affected zone (HAZ) of a welding joint in low-carbon steels. The relationship between the cooling rate and the density and size of inclusions was analyzed. An orientation relationship akin to the Baker–Nutting relationship was identified between TiN and ferrite, while the orientation relationship between MnS and ferrite approximated the Kurdjumov–Sachs relationship. At low cooling rates, in the absence of nucleation support from TiN and MnS inclusions, the microstructure in the HAZ comprised Widmanstätten ferrite. Additionally, the shape, size, and density of primary ferrites and Widmanstätten ferrite in steels were influenced by sulfur content.