| 1. |
- Yue, Xiaoqi, et al.
(författare)
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Unveiling nano-scale chemical inhomogeneity in surface oxide films formed on V- and N-containing martensite stainless steel by synchrotron X-ray photoelectron emission spectroscopy/microscopy and microscopic X-ray absorption spectroscopy
- 2025
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Ingår i: Journal of Materials Science & Technology. - : Chinese Society of Metals. - 1005-0302. ; 205, s. 191-203
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Tidskriftsartikel (refereegranskat)abstract
- Nano-scale chemical inhomogeneity in surface oxide films formed on a V- and N-containing martensite stainless steel and tempering heating induced changes are investigated by a combination of synchrotron- based hard X-ray Photoelectron emission spectroscopy (HAXPES) and microscopy (HAXPEEM) as well as microscopic X-ray absorption spectroscopy (μ-XAS) techniques. The results reveal the inhomogeneity in the oxide films on the micron-sized Cr2N- and VN-type particles, while the inhomogeneity on the martensite matrix phase exists due to localised formation of nano-sized tempering nitride particles at 600 °C. The oxide film formed on Cr2N-type particles is rich in Cr2O3 compared with that on the martensite matrix and VN-type particles. With the increase of tempering temperature, Cr2O3 formation is faster for the oxidation of Cr in the martensite matrix than the oxidation of Cr nitride-rich particles.
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| 2. |
- Sarmad, Shokat, et al.
(författare)
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Innovative CO2 capture technologies: Exploring the potential of porous liquids containing deep eutectic solvents and hypercrosslinked polymers
- 2025
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Ingår i: Separation and Purification Technology. - : Elsevier B.V.. - 1383-5866 .- 1873-3794. ; 352
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Tidskriftsartikel (refereegranskat)abstract
- The current study presented a porous liquid (PL) prepared from propylene glycol-based deep eutectic solvent (DES) and hyper-crosslinked polymers (HCP) that are liquids over wide temperature ranges, including ambient temperature. It was shown that the solvent molecules are too large to penetrate the pores of HCP, so the PL is maintained as a suspension with permanent free volume for several months and can absorb large amounts of gases. This study marks the pioneering use of DESs as the liquid medium, replacing ionic liquids due to their closely matched properties. The structural features of both DES and HCP are retained; the increase in CO2 absorption capacity compared to pure DES is due to the presence of a porous solid and is proportional to the amount of solid. The absorbed CO2 amount rises from 1.0105 mmol·g−1 in pure DES to 1.3232, 1.6027, and 1.2168 mmol·g−1 in PL-1, PL-2, and PL-3, respectively. Thermodynamic analysis revealed that the enthalpy of gas absorption allows straightforward regeneration of the PLs in the studied cases. The investigated PLs show great potential as gas absorbents, with the incorporation of just 0.5 wt% of porous polymer material leading to an impressive increase in solvent absorption capacity, up to 59 %.
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| 3. |
- Abdi, Somayeh, et al.
(författare)
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Deadline-constrained security-aware workflow scheduling in hybrid cloud architecture
- 2025
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Ingår i: Future Generation Computer Systems. - : Elsevier B.V.. - 0167-739X .- 1872-7115. ; 162
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Tidskriftsartikel (refereegranskat)abstract
- A hybrid cloud is an efficient solution to deal with the problem of insufficient resources of a private cloud when computing demands increase beyond its resource capacities. Cost-efficient workflow scheduling, considering security requirements and data dependency among tasks, is a prominent issue in the hybrid cloud. To address this problem, we propose a mathematical model that minimizes the monetary cost of executing a workflow and satisfies the security requirements of tasks under a deadline. The proposed model fulfills data dependency among tasks, and data transmission time is formulated with exact mathematical expressions. The derived model is a Mixed-integer linear programming problem. We evaluate the proposed model with real-world workflows over changes in the input variables of the model, such as the deadline and security requirements. This paper also presents a post-optimality analysis that investigates the stability of the assignment problem. The experimental results show that the proposed model minimizes the cost by decreasing inter-cloud communications for dependent tasks. However, the optimal solutions are affected by the limitations that are imposed by the problem constraints.
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| 4. |
- Achieng, Pauline, et al.
(författare)
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Reconstructing of the radiation condition and solution for a variable coefficient Helmholtz equation in a semi-infinite strip from Cauchy data on an interior segment
- 2025
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Ingår i: Journal of Mathematical Analysis and Applications. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 0022-247X .- 1096-0813. ; 541:1
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Tidskriftsartikel (refereegranskat)abstract
- We consider the Helmholtz equation with a variable coefficient in a semi-infinite strip. Homogeneous Neumann conditions are prescribed on a part of the boundary of the strip. Our aim is to find the unknown function in the Dirichlet boundary condition on the remaining part of the boundary from measurements taken on a segment inside the semi-infinite strip. We assume that the radiation condition at infinity is unknown and must be found also. The main difficulty here is the variable coefficient in the Helmholtz equation which does not allow to apply the method of separation of variable as was done in [2]. Such problems appear in acoustics to determine acoustical sources and surface vibrations from acoustic field measurements in non-uniform mediums. We split the problem in two parts. One consists of finding the radiation condition and this problem is well-posed. We derive the equation for finding the parameter of the radiation condition, that holds at infinity. The second one is to find the Dirichlet data and this problem is ill-posed. We present an operator equation with compact operator for finding the Dirichlet data. (c) 2024 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons .org /licenses /by /4 .0/).
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| 5. |
- Lu, Fengyi, et al.
(författare)
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Integrated optimisation of multi-pass cutting parameters and tool path with hierarchical reinforcement learning towards green manufacturing
- 2025
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Ingår i: Robotics and Computer-Integrated Manufacturing. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0736-5845 .- 1879-2537. ; 91
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Tidskriftsartikel (refereegranskat)abstract
- Five-axis machining, especially flank milling, is popular in machining thin-walled freeform surface parts with high energy consumption. Reducing the machining energy consumption is paramount for advancing green manufacturing. Therefore, this paper proposes an energy-efficient integration optimisation of cutting parameters and tool path with hierarchical reinforcement learning (HRL). Firstly, a novel multi-pass machining energy consumption model is developed with cutting and path parameters, based on which the integrated optimisation problem is modelled considering a dynamic workpiece deformation constraint. Secondly, HRL with a Soft Actor Critic agent (HSAC) decouples the model into two Markov Decision Processes at different timescales. The higherlayer plans cutting parameters for each pass on a macro timescale, while the micro-timescale lower-layer performs multiple tool path expansions with the planned cutting parameters, and provides feedback to the higher layer. By hierarchical optimisation and non-hierarchical interaction, the model is efficiently solved. Moreover, curriculum transfer learning is applied to expedite task completion of the lower layer, enhancing interaction efficiency between the two layers. Experiments show that, compared with two benchmarks, the proposed method improves machining energy consumption by 35.02 % and 30.92 %, and reduces machining time by 38.57 % and 27.17 %, providing a promising paradigm of green practices for thin-walled freeform parts and the broader manufacturing industry.
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| 6. |
- Sarmad, Shokat, et al.
(författare)
-
Innovative CO2 capture technologies: Exploring the potential of porous liquids containing deep eutectic solvents and hypercrosslinked polymers
- 2025
-
Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 352
-
Tidskriftsartikel (refereegranskat)abstract
- The current study presented a porous liquid (PL) prepared from propylene glycol-based deep eutectic solvent (DES) and hyper-crosslinked polymers (HCP) that are liquids over wide temperature ranges, including ambient temperature. It was shown that the solvent molecules are too large to penetrate the pores of HCP, so the PL is maintained as a suspension with permanent free volume for several months and can absorb large amounts of gases. This study marks the pioneering use of DESs as the liquid medium, replacing ionic liquids due to their closely matched properties. The structural features of both DES and HCP are retained; the increase in CO2 absorption capacity compared to pure DES is due to the presence of a porous solid and is proportional to the amount of solid. The absorbed CO2 amount rises from 1.0105 mmol·g−1 in pure DES to 1.3232, 1.6027, and 1.2168 mmol·g−1 in PL-1, PL-2, and PL-3, respectively. Thermodynamic analysis revealed that the enthalpy of gas absorption allows straightforward regeneration of the PLs in the studied cases. The investigated PLs show great potential as gas absorbents, with the incorporation of just 0.5 wt% of porous polymer material leading to an impressive increase in solvent absorption capacity, up to 59 %.
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| 7. |
- Sun, Mingyue, et al.
(författare)
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Out-of-order execution enabled deep reinforcement learning for dynamic additive manufacturing scheduling
- 2025
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Ingår i: Robotics and Computer-Integrated Manufacturing. - : Elsevier Ltd. - 0736-5845 .- 1879-2537. ; 91
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Tidskriftsartikel (refereegranskat)abstract
- Additive Manufacturing (AM) has revolutionized the production landscape by enabling on-demand customized manufacturing. However, the efficient management of dynamic AM orders poses significant challenges for production planning and scheduling. This paper addresses the dynamic scheduling problem considering batch processing, random order arrival and machine eligibility constraints, aiming to minimize total tardiness in a parallel non-identical AM machine environment. To tackle this problem, we propose the out-of-order enabled dueling deep Q network (O3-DDQN) approach. In the proposed approach, the problem is formulated as a Markov decision process (MDP). Three-dimensional features, encompassing dynamic orders, AM machines, and delays, are extracted using a ‘look around’ method to represent the production status at a rescheduling point. Additionally, five novel composite scheduling rules based on the out-of-order principle are introduced for selection when an AM machine completes processing or a new order arrives. Moreover, we design a reward function that is strongly correlated with the objective to evaluate the agent's chosen action. Experimental results demonstrate the superiority of the O3-DDQN approach over single scheduling rules, randomly selected rules, and the classic DQN method. The average improvement rate of performance reaches 13.09% compared to composite scheduling rules and random rules. Additionally, the O3-DDQN outperforms the classic DQN agent with a 6.54% improvement rate. The O3-DDQN algorithm improves scheduling in dynamic AM environments, enhancing productivity and on-time delivery. This research contributes to advancing AM production and offers insights into efficient resource allocation.
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| 8. |
- Wang, Chao, et al.
(författare)
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Characterization and sources of childhood PAEs exposure from residential airborne dust in China cities
- 2025
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Ingår i: Journal of Environmental Sciences(China). - : Elsevier. - 1001-0742 .- 1878-7320. ; 152, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- To explore the multicenter characteristics of endocrine-like phthalate esters (PAEs) in household dust and propose effective control strategies for global indoor public health. An on-site observational investigation was conducted in nine Chinese cities from 2018 to 2019. A total of 246 household dust samples were collected and analyzed for ten PAE congeners using Gas Chromatography-Mass Spectrometry (GC-MS). Questionnaires were used to gather information on building conditions, indoor behaviors, and ventilation habits. In residential dust from the nine cities, the total concentrations of the ten PAE congeners (∑PAEs) ranged from 0.921 to 29097.297 µg/g. Dicyclohexyl phthalate (DCHP) and di (2-ethylhexyl) phthalate (DEHP) were the dominant congeners in ∑PAEs. Childhood exposure to PAEs through dust ingestion was four orders of magnitude higher than through inhalation, with a carcinogenic risk of 5.47 × 10−6 for DEHP exposure in household dust. Higher ∑PAEs concentrations were associated with higher temperature, double glazing, wall paint usage, television and computer use, and indoor plant growth. This multicenter on-site investigation confirmed PAE pollution characteristics and uncovered the inacceptable risk of daily DEHP exposure in household dust under real living conditions. Effective mitigation measures based on household-related information, residential characteristics, decoration materials, and lifestyle should be taken to build a healthy household environment.
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| 9. |
- Zhou, Zhenning, et al.
(författare)
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Learning accurate and efficient three-finger grasp generation in clutters with an auto-annotated large-scale dataset
- 2025
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Ingår i: Robotics and Computer-Integrated Manufacturing. - : Elsevier BV. - 0736-5845 .- 1879-2537. ; 91
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Tidskriftsartikel (refereegranskat)abstract
- With the development of intelligent manufacturing and robotic technologies, the capability of grasping unknown objects in unstructured environments is becoming more prominent for robots with extensive applications. However, current robotic three-finger grasping studies only focus on grasp generation for single objects or scattered scenes, and suffer from high time expenditure to label grasp ground truth, making them incapable of predicting grasp poses for cluttered objects or generating large-scale datasets. To address such limitations, we first introduce a novel three-finger grasp representation with fewer prediction dimensions, which balances the training difficulty and representation accuracy to obtain efficient grasp performance. Based on this representation, we develop an auto-annotation pipeline and contribute a large-scale three-finger grasp dataset (TF-Grasp Dataset). Our dataset contains 222,720 RGB-D images with over 2 billion grasp annotations in cluttered scenes. In addition, we also propose a three-finger grasp pose detection network (TF-GPD), which detects globally while fine-tuning locally to predict high-quality collision-free grasps from a single-view point cloud. In sum, our work addresses the issue of high-quality collision-free three-finger grasp generation in cluttered scenes based on the proposed pipeline. Extensive comparative experiments show that our proposed methodology outperforms previous methods and improves the grasp quality and efficiency in clutters. The superior results in real-world robot grasping experiments not only prove the reliability of our grasp model but also pave the way for practical applications of three-finger grasping. Our dataset and source code will be released.
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| 10. |
- Gao, Guangbin, et al.
(författare)
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Understanding filamentous cyanobacteria and their adaptive niches in Lake Honghu, a shallow eutrophic lake
- 2025
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Ingår i: Journal of Environmental Sciences (China). - 1001-0742. ; 152, s. 219-234
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Tidskriftsartikel (refereegranskat)abstract
- Freshwater lakes globally are witnessing an escalation in the frequency and intensity of cyanobacterial harmful blooms. However, underlying factors influencing the succession or coexistence of cyanobacteria, especially filamentous ones, remain poorly understood. Lake Honghu, a Ramsar Wetland of International Importance with degrading aquatic ecological quality, served as a case study to elucidate the intricate relationship between environmental changes and cyanobacterial dynamics. Our analysis revealed a significant increase in the dominance of filamentous cyanobacteria, marked by high spatiotemporal variability in community structure. This dominance of filamentous diazotrophic cyanobacteria is attributed to a decrease in the ratio of dissolved inorganic nitrogen to total phosphorus and their capacity to utilize organic phosphorus in phosphorus-deficient conditions. Species-specific density variations were linked to diverse environmental factors, with total nitrogen or total phosphorus concentration remaining as a crucial factor influencing dominant cyanobacterial density fluctuations. The dominance of low-temperature-tolerant Aphanizomenon and Pseudanabaena was evident in spring and winter, whereas Dolichospermum and Cylindrospermopsis, which prefer higher temperatures, thrived in summer and autumn. Additionally, non-algal turbidity and heterogeneity can potentially alter the competitive outcome among filamentous cyanobacteria or foster coexistence under conditions of elevated temperatures and nutrient limitation. This study predicts that filamentous cyanobacteria may spread and persist in lakes spanning a wide trophic range. Current findings enhance our comprehension of the dynamic responses exhibited by filamentous bloom-forming cyanobacteria in the face of environmental changes within shallow eutrophic lakes and provide valuable insights for lake managers involved in the remediation of degraded shallow lakes.
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