139585 research outputs found
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An efficient temperature dependent compact model for nanosheet FET for neuromorphic computing circuit
No full textPublisher Copyright: © 2025 Elsevier LtdIn this work, a temperature-dependent compact model is proposed for the three-sheet (3S) Nanosheet (NS) FET. This model is developed because a computationally efficient model is needed for large-scale circuit design. The model is based on the virtual source (VS) principle, which is chosen because for its simple mathematical formulation and minimal parameter requirements. This allows the model to accurately capture the performance characteristics of the 3S NSFET. The model is validated using TCAD results, which are well-calibrated with experimental data. It is then implemented in Verilog-A code for neuromorphic circuit simulations. Herein, we analyses the important parameters such as power, energy, and spiking frequency in NSFET-based leaky integrate-and-fire (LIF) neurons, with temperature variations. The results show that as the temperature increased from 25 °C to 125 °C, the spiking frequency increased by 36.64 %, due to higher current in the subthreshold operation of the device.Peer reviewe
Evaluating the sustainability and leverage potential of innovative organic farming systems
No full textPublisher Copyright: © 2024Modern agriculture has advanced food security but at an environmental cost. Organic farming and agroforestry have been proposed as alternatives, however, evaluating their sustainability is challenging due to heterogeneity of the sector, a relatively small number of sustainability assessments carried out and lack of user-friendly assessment tools. Holistic sustainability analyses, including ecosystem services provided by farms, are essential to evaluate food and farming systems and inform policies. In this study, we aim to identify key characteristics of innovative organic case study farms and evaluate how innovative organic farms compare across multiple dimensions of sustainability. In addition, the study aims to identify key leverage points within these farming systems and evaluate how these influence sustainability performance in environmental, economic, social and governance domains. Farm performance was evaluated using the Public Goods tool which is a sustainability assessment tool for evaluating different aspects of sustainability at the farm level. The findings from eight organic farming case studies showed good sustainability performance in most of the examined sustainability aspects, with areas for improvement in energy, carbon, and water management. The farms scored highly in farm business resilience, system diversity, social capital and soil management. There was a strong positive relationship between “farm business resilience” (e.g. sources of farm income, satisfaction with farming system) and “social capital” (e.g. training of farm workers and community involvement) suggesting a possible relationship between financial and economic factors and social wellbeing. In addition, all case study farms demonstrated a clear objective for their operations and a strong vision for enhancing sustainability. This was reflected in their high scores for the leverage point categories of ‘design’ and ‘intent’. To achieve their objectives, farmers proactively sought knowledge to guide system design decisions. They also engaged in knowledge sharing, social and community engagement through networks, and direct marketing to inform and ‘reconnect’ peers with food and farming systems, while reducing reliance on long supply chains. Future research and rural policy should work together and focus on how to operationalize holistic sustainability assessment and key leverage points to make farms and rural communities more sustainable and resilient to both expected and unexpected challenges.Peer reviewe
Precision benchmarks for solids : G0W0 calculations with different basis sets
No full textPublisher Copyright: © 2025 Elsevier B.V.The GW approximation within many-body perturbation theory is the state of the art for computing quasiparticle energies in solids. Typically, Kohn–Sham (KS) eigenvalues and eigenfunctions, obtained from a Density Functional Theory (DFT) calculation are used as a starting point to build the Green's function G and the screened Coulomb interaction W, yielding the one-shot G0W0 self-energy if no further update of these quantities are made. Multiple implementations exist for both the DFT and the subsequent G0W0 calculation, leading to possible differences in quasiparticle energies. In the present work, the G0W0 quasiparticle energies for states close to the band gap are calculated for six crystalline solids, using four different codes: Abinit, exciting, FHI-aims, and GPAW. This comparison helps to assess the impact of basis-set types (planewaves versus localized orbitals) and the treatment of core and valence electrons (all-electron full potentials versus pseudopotentials). The impact of unoccupied states as well as the algorithms for solving the quasiparticle equation are also briefly discussed. For the KS-DFT band gaps, we observe good agreement between all codes, with differences not exceeding 0.1 eV, while the G0W0 results deviate on the order of 0.1-0.3 eV. Between all-electron codes (FHI-aims and exciting), the agreement is better than 15 meV for KS-DFT and, with one exception, about 0.1 eV for G0W0 band gaps.Peer reviewe
Synergy between adsorption and bio-degradation of real wastewater polycyclic aromatic hydrocarbons (PAHs) by laccase immobilized on pineapples waste activated carbon : Recyclability, performance, and DFT analysis
No full textPublisher Copyright: © 2025 Elsevier LtdThe contamination of micropollutants in wastewater has become a global issue due to their persistent impact on ecosystems and human health. The enzymatic degradation of polycyclic aromatic hydrocarbons (PAHs) offers a promising, sustainable approach, although it is limited by reduced stability and recycling challenges. In this study, we demonstrated the use of pineapple peel waste as a novel support for the immobilization of laccase (Trametes versicolor) via an adsorption technique (laccase@PPAC). The activated carbon synthesized using potassium hydroxide (PPAC), and laccase@PPAC were characterized through various methods. The laccase@PPAC exhibited excellent performance, achieving maximum adsorption capacities of 270.38 mg/g for benzo[a]pyrene (BaP) and 335.27 mg/g for anthracene (Ant). When combined with enzymatic degradation, total removal reached 98.72 % for BaP and 99.87 % for Ant, corresponding to total degradation-enhanced capacities of 301.21 mg/g and 317.41 mg/g, respectively. Additionally, laccase@PPAC maintained high removal efficiency over 20 reuse cycles. The system showed superior thermostability and pH tolerance compared to free-state laccase. Adsorption kinetics followed the pseudo-first-order model, while equilibrium data were best described by the Langmuir isotherm. This work highlights the potential of pineapple waste-derived activated carbon as a sustainable and effective support for enzyme immobilization in the bioremediation of PAHs-contaminated wastewater.Peer reviewe
STPA-Cyber: A semi-automated cyber risk assessment framework for maritime cybersecurity
No full textCybersecurity incidents in the maritime sector are growing in number and the requirement of cyber risk management onboard ships is an inescapable reality today. Multiple cyber risk assessment frameworks exist today but they are all cumbersome to be applied in today’s state-of-the-art modern maritime systems. Most of the frameworks require experts’ involvement, their precious time and cognitive efforts. The application of these frameworks are also prone to human biases. Moreover, due to the rapid evolution of malicious actors and the inclusion of state-of-the-art toolsets in their arsenal, the completeness of the coverage of the cyber risk analysis for modern maritime systems is also open to questions. In response to these emerging challenges and threat landscape, a modified system theoretic process analysis for cybersecurity is proposed that not only inspects the control actions from a controller but also investigates the incoming feedback signals from the controlled process. The rationale behind the two-way cyber risk analysis within a system, i.e., for a control action as well as for a feedback signal, is that the attackers can target both the links within a feedback loop with comparable likelihood and impact, which could result in gruesome consequences. This work also contributes by semi-automating the labor intensive steps of the cyber risk assessment that results in significant reduction of involvement of experts, cognitive efforts, time requirement and human biases. Lastly, semi-automated generation of security causal scenarios in this work also contributes to the completeness of the cyber risk assessment process because human involvement and manual efforts required in the cyber risk assessment of a cyber–physical system could result in incomplete analysis due to the limitations in human comprehension. Hence, considerable reductions in time, cognitive efforts, human involvement and human biases are achieved in this work.Peer reviewe
Distributionally robust chance-constrained energy management for island DC microgrid with offshore wind power hydrogen production
No full textPublisher Copyright: © 2025 Elsevier LtdIslands possess abundant renewable energy resources with significant potential for development. Meanwhile, the off-grid DC electro-hydrogen coupled systems is a promising way for the development of marine economy. This paper presents a distributionally robust chance-constrained (DRCC) energy management model for island DC electro-hydrogen microgrid considering the offshore wind power hydrogen production. Firstly, a comprehensive hydrogen-related model incorporating the dynamic hydrogen production, storage, and utilization is proposed, where the nonlinear hydrogen production efficiency of electrolyzer is considered. Then, a data-driven DRCC energy management model for island DC electro-hydrogen microgrid is developed, where the metric-based ambiguity set is leveraged to capture the uncertainty of offshore wind power. Besides, the conditional value-at-risk (CVaR) approximation is tailored to reformulate the resulting metric-based DRCC model into a tractable form. Numerical results on an off-grid DC electro-hydrogen coupled systems illustrate the effectiveness of the proposed approach.Peer reviewe
Deflection and thickness threshold of high-strength strain-hardening cementitious composite stay-in-place formwork for modular integrated construction
No full text| openaire: EC/HE/101105930/EU//CCU Structure Publisher Copyright: © 2025 Elsevier LtdConcrete modular integrated construction (MiC) involves stay-in-place (SIP) wall formwork during construction, which is subjected to lateral pressure from cast-in-situ fresh concrete and is usually thick and heavily reinforced to limit deflection and cracking. Strain-hardening cementitious composite (SHCC) with strain-hardening and multiple cracking behaviors could significantly reduce the wall thickness. However, the maximum deflection and thickness threshold of SHCC wall formwork under casting loads are unknown. In this paper, the bending tests of half-scale SHCC plates with varying thicknesses, reinforcement layouts, and boundary conditions were first performed. Due to the fiber-bridging behavior, numerous micro-cracks appeared on the plate surfaces and the SHCC plates presented excellent bending ductility. Placing transverse rebars close to the outer surface, increasing plate thickness, and enhancing boundaries could effectively delay the cracking. Subsequently, a refined finite element (FE) model for the bending test was built and validated by the test results. 128 FE models were calculated to investigate the effects of plate thickness, plate widths, and reinforcement ratios. The maximum deflection increased with plate widths, indicating that a wider wall formwork required a larger thickness. Finally, the deflection calculation procedure of SHCC wall formwork was proposed based on the calculus of variations and the Galerkin method. The thickness thresholds of SHCC wall formwork with the widths of 1000, 1500, 2000, and 2500 mm are 50, 60, 70, and 80 mm, respectively.Peer reviewe
Multi-timescale risk-averse restoration for interdependent water–power networks with joint reconfiguration and diverse uncertainties
No full textPublisher Copyright: © 2025 Elsevier LtdThe growing interdependencies between water and power systems have increased the risk of cascading disruptions and widespread blackouts. Such interdependencies, together with different operational characteristics and multiple uncertainties, introduce additional complexities to service restoration. To address these issues, this paper proposes a coordinated multi-timescale restoration strategy for interdependent water–power networks (IWPNs). First, we model the IWPN as network-based with physical mechanisms, incorporating component-wise interdependencies and varying consumer demands. Features comprising pipe damage (water leakage) and storage as well as renewable generations are modelled to better reflect restoration better. Specifically, the joint reconfigurability of water and power networks is first applied for adjustment of topologies and leverages off backup components by coordinated setting of valves and switches. Then, an updated estimation for multiple uncertainties during restoration is utilized, which offers increasing clarity to support better decision-making. These uncertainties arise from renewable generations and water and power demands. A multi-timescale decision framework is developed to capture these effects and tune restoration measures based on response speeds to facilitate efficient and reliable restoration. Finally, the method is implemented by combining robust optimization and risk-averse stochastic programming and applied to a community-scale test system with 25 water nodes and 33 power buses. The proposed method is compared with five conventional methods with numerical results demonstrating the improvements arising from an interdependent restoration, joint reconfigurability, and multi-timescale optimizations.Peer reviewe
Colloidal lignin valorization : From macromolecular design to targeted applications
No full text| openaire: EC/H2020/742829/EU//DRIVENConverting lignin into useful colloidal entities with uniform size and shape offers exciting opportunities for utilization; however, this endeavor requires overcoming challenges caused by structural heterogeneity and gaining further understanding to exploit its unique functional possibilities. Still, colloidal lignin has already provided new insights into bio-polymeric materials and has triggered various innovative applications that have inspired the scientific community. This review aims to provide a comprehensive discussion of the current understanding of colloidal lignin and its emergent applications. First, a fundamental overview of lignin, including its chemistry and processing is provided. Subsequently, a multitude of technical routes to tune the properties of colloidal lignin using nano-/micro-fabrication approaches to control macroscale properties is presented. Thereafter, examples of innovative material technologies based on colloidal lignin in areas such as pollution remediation, polymeric materials, macromolecular materials, and drug delivery are given. Finally, open challenges and suggestions for future research will be discussed to guide future research to rationally expand the portfolio of promising lignin-based technologies.Peer reviewe
Critical discussion on the challenges of integrating heat pumps in hydronic systems in existing buildings
No full textThe integration of heat pumps into existing buildings is one option to exploit carbon neutral heat and cool sources. Today, this is in line with planned electrification and paths to achieve nearly zero energy buildings by using renewable energy sources. However, the implementation process is more complex compared to new buildings. Moreover, there is no comprehensive study that depicts and critically discusses the main challenges associated with integrating heat pumps into existing buildings from a very practical point of view. This article presents the main technical and economic challenges related to the application of heat pumps in existing building stock based on critical literature review and discussion. Among others, especially, procedures involving the reduction of the supply temperature of the heating medium, the selection of the bivalent point, heat storage, and buffer tanks of heat pumps were discussed. Several best practices for the design and control of the heat pumps in existing buildings along with a discussion of benefits and limitations (technical, economic, operational) of the analyzed systems are provided. Key findings are: (i) it was indicated that the heat pumps in existing buildings can be applied as a heat source for the entire building, part or single room and for different purposes (space heating and/or DHW and/or cooling), (ii) minimisation of the supply temperature is always desirable, with the limit for DHW being 58 °C, and ultimately the control should be adapted to the building or replaced by forecast-based control, (iii) coverage of heat demand by heat pumps should reach 70–90 % of peak demand at nominal outdoor air conditions and be determined on the basis of the analysis of initial and running costs, (iv) from the point of view of reducing the demand for primary energy self-consumption of electricity from PV should be maximised. Finally, future research and development directions are suggested.Peer reviewe