Experimental Investigation on Magnetic Abrasive Finishing for Internal Surfaces of Waveguides Produced by Selective Laser Melting.

To enhance the surface quality of metal 3D-printed components, magnetic abrasive finishing (MAF) technology was employed for post-processing polishing. Experimental investigation employing response surface methodology was conducted to explore the impact of processing gap, rotational speed of the magnetic field, auxiliary vibration, and magnetic abrasive particle (MAP) size on the quality enhancement of internal surfaces. A regression model correlating roughness with crucial process parameters was established, followed by parameter optimization. Ultimately, the internal surface finishing of waveguides with blind cavities was achieved, and the finishing quality was comprehensively evaluated. Results indicate that under optimal process conditions, the roughness of the specimens decreased from Ra 2.5 µm to Ra 0.65 µm, reflecting a reduction rate of 74%. Following sequential rough and fine processing, the roughnesses of the cavity bottom, side wall, and convex surface inside the waveguide reduced to 0.59 µm, 0.61 µm, and 1.9 µm, respectively, from the original Ra above 12 µm. The findings of this study provide valuable technical insights into the surface finishing of metal 3D-printed components.

Interface Hardness Analysis of between IN625 and CoCrMo Manufactured by Pulsed Wave Laser Powder Bed Fusion.

The nuclear and petrochemical industries often require multi-metal parts that are corrosion-resistant, heat-resistant, and possess high strength to enhance equipment safety and reduce downtime. Additive manufacturing technology enables the rapid and flexible processing of multi-metal parts to meet these stringent demands. This study is aimed at investigating the interface hardness between CoCrMo/IN625 to determine optimal processing parameters that can be utilized in manufacturing reliable and durable multi-metal parts. The result indicates that when the volumetric energy density, Ev, is at or below 20 J/mm3, microfluidic forces are unable to sufficiently diffuse between the two metals, leading to insufficient diffusion, and the high hardness CoCrMo acts as a support, resulting in a significantly higher interface hardness. As Ev increases, intense recoil pressure within the microfluidic forces disrupts the melt pool, allowing for full diffusion between the two metals. The fully diffused high-hardness CoCrMo has been diluted by the low-hardness IN625, thus reducing the interface hardness. Considering the interface hardness, strength, and printing efficiency (time and energy consumption), we recommend a range of 35 J/mm3 < Ev ≤ 75 J/mm3. In this range, the average values for interface hardness and tensile strength of the samples are approximately 382 HV and 903 MPa, respectively.

Assessing the option water-saving willingness of irrigation areas considering farmers' risk tolerance.

Water option trading could facilitate water conservation in irrigation areas to achieve optimal allocation of agricultural water resources. However, the risk associated with water-saving decisions increases due to the uncertainties of tradeable water and water-saving benefits, which makes farmers in the irrigation area with heterogeneous risk tolerances exhibit varied option water-saving willingness (OWSW) in response to the water option contract. Thus, this article provides a novel framework for prior assessing the OWSW in the irrigated area that considers farmers' heterogeneous risk tolerance and proposes the optimal contractual water demand to stimulate the OWSW. First, a multiobjective optimal allocation model for cropping water is constructed to predict tradeable water, and then risk trust, risk-return perception and reference are integrated into water-saving return analysis for proposing a willingness calculation model involving forecast information. Finally, the influence of heterogeneous risk tolerance on farmers' water-saving path choices and the irrigation area's OWSW is analyzed with three sets of comparative data from 2014 to 2021. Results indicate that the intensity and stability of OWSW in water-scarce irrigation areas increase as farmers' risk tolerance rises, but the enhancement utility exhibits a diminishing marginal trend. When both prediction accuracy and farmers' risk tolerance are low, contracts with relatively adventurous and differentiated water demands are more likely to stimulate OWSW. This study provides insights into activating water options trading and stimulating water conservation in agriculture from a risk management perspective.

Interface Analysis between Inconel 625 and Cobalt-Chromium Alloy Fabricated by Powder Bed Fusion Using Pulsed Wave Laser.

A few components used in the aerospace and petrochemical industries serve in corrosive environments at high temperatures. Corrosion-resistant metals or unique processes, such as coating and fusion welding, are required to improve the performance of the parts. We have used laser powder bed fusion (LPBF) technology to deposit a 5 mm thick corrosion-resistant CoCrMo layer on a high-strength IN625 substrate to improve the corrosion resistance of the core parts of a valve. This study found that when the laser volumetric energy density (EV) ≤ 20, the tensile strength increases linearly with the increase in EV, and the slope of the curve is approximately 85°. The larger the slope, the greater the impact of EV on the intensity. When EV > 20, the sample strength reaches the maximum tensile strength. When the EV increases from 0 to 20, the fracture position of the sample shifts from CoCrMo to IN625. When EV ≤ 38, the strain increases linearly with the increase in EV, and the slope of the curve is approximately 67.5°. The sample strain rate reaches the maximum when EV > 38. Therefore, for an optimal sample strength and strain, EV should be greater than 38. This study provides theoretical and technical support for the manufacturing of corrosion-resistant dissimilar metal parts using LPBF technology.

Multimetal Research in Powder Bed Fusion: A Review.

This article discusses the different forms of powder bed fusion (PBF) techniques, namely laser powder bed fusion (LPBF), electron beam powder bed fusion (EB-PBF) and large-area pulsed laser powder bed fusion (L-APBF). The challenges faced in multimetal additive manufacturing, including material compatibility, porosity, cracks, loss of alloying elements and oxide inclusions, have been extensively discussed. Solutions proposed to overcome these challenges include the optimization of printing parameters, the use of support structures, and post-processing techniques. Future research on metal composites, functionally graded materials, multi-alloy structures and materials with tailored properties are needed to address these challenges and improve the quality and reliability of the final product. The advancement of multimetal additive manufacturing can offer significant benefits for various industries.

Towards carbon neutrality: what has been done and what needs to be done for carbon emission reduction?

Carbon emissions embodied in anthropogenic activities represent the major cause of global warming. Countries, regions, and cities have implemented comprehensive, multi-level and multi-scale measures to reduce emissions and move towards carbon neutrality. The demand for carbon emission reduction (CER) is made more challenging by different geographical locations, country-owned natural resources, and economic development stages. The main objectives of this paper are to conduct a bibliometric analysis to map the frontiers and directions of CER and to explore the paths and development models of CER from the perspective of spatio-temporal, multi-scale, multi-sectoral, and multi-responsible subjects. This study reveals that carbon emission evaluation and prediction, correlation and causal relationship analysis, and CER-related policy simulation and optimization are the most critical hotspots. Additionally, we point out the shortcomings of and future developments for the three study dimensions above. The bibliometric analysis also highlights the fact that a cooperative global value chain as well as amendable policies and mechanisms for CER will help with climate change mitigation and adaptation through the use of advanced carbon capture and storage technologies. We review the technical measures for and policy responses to CER adopted by different countries and industries at the theoretical and practical levels and provide new recommendations. Our work provides important information for climate actions in different countries and sectors and for developing more effective CER strategies and policies.

Multi-omics analysis reveals cuproptosis and mitochondria-based signature for assessing prognosis and immune landscape in osteosarcoma.

Background: Osteosarcoma (OSA), the most common primary mesenchymal bone tumor, is a health threat to children and adolescents with a dismal prognosis. While cuproptosis and mitochondria dysfunction have been demonstrated to exert a crucial role in tumor progression and development, the mechanisms by which they are regulated in OSA still await clarification. Methods: Two independent OSA cohorts containing transcriptome data and clinical information were collected from public databases. The heterogeneity of OSA were evaluated by single cell RNA (scRNA) analysis. To identify a newly molecular subtype, unsupervised consensus clustering was conducted. Cox relevant regression methods were utilized to establish a prognostic gene signature. Wet lab experiments were performed to confirm the effect of model gene in OSA cells. Results: We determined 30 distinct cell clusters and assessed OSA heterogeneity and stemness scRNA analysis. Then, univariate Cox analysis identified 24 candidate genes which were greatly associated with the prognosis of OSA. Based on these prognostic genes, we obtained two molecular subgroups. After conducting step Cox regression, three model genes were selected to construct a signature showing a favorable performance to forecast clinical outcome. Our proposed signature could also evaluate the response to chemotherapy and immunotherapy of OSA cases. Conclusion: We generated a novel risk model based on cuproptosis and mitochondria-related genes in OSA with powerful predictive ability in prognosis and immune landscape.

Robust optimization with equity and efficiency framework for basin-wide water resources planning.

This study proposes an equitable and effective water resource planning framework that handles competing regions and conflicting water departments within water-stressed watersheds under uncertainty. To cope with uncertainty, a robust optimization method based on an ellipsoidal uncertainty set is presented to keep the best solution viable and less conservative while attempting to find a balance between the reliability and optimum goals. The comprehensive framework consists of two predominant steps: equitable initial water allocation robust optimization programming, which employs the absolute difference between the supply and demand of water resources as the objective function and the Gini coefficient as the restricted condition, given that both surface water and groundwater are random, and subsequent effective water re-allocation robust modeling, which applies cooperative game theory to achieve maximum welfare in a river basin under uncertainty of the benefit coefficient. A realistic example of the Tuojiang River Basin was conducted, and the simulation experiments showed a significant increase (79.20%) in reliability with only an 11.44% increase in objective values and 2.76% and 15.17% decreases in the amount of surface water and groundwater, respectively. The findings of the analysis reveal that robust policies achieve adaptive optimal decision-making under uncertainty at a low cost.

Optimal allocation and transaction of waste load permits for transboundary basin: A Bi-level programming approach based on node-arc.

Inadequate water quality exacerbates global water resources scarcity. Hence, water quality of the river basin is increasingly perceived as a global obstacle to sustainable development because of the limited water carrying capacity. Efficient waste load permits (WLPs) allocation plays a critical role in enhancing water quality by controlling the emission cap. Considering transboundary water pollution and transaction among regions, a bi-level objective model is proposed to analyze the WLPs allocation based on the node-arc method. Motivated by alleviating regional development differences, the watershed management committee concentrates on equitable distribution of WLPs to regions. Furthermore, regional authorities focus on how to guarantee the maximum economic development and balance the WLPs emissions from the municipal, industrial, and agricultural sectors. Practicality and efficiency of the constructed model is demonstrated by applying it to Tuojiang River Basin. Through the analysis of the results, three management recommendations are proposed for Tuojiang River: strengthening the prevention of agricultural non-point source pollution, sticking to the cooperation between upstream and downstream regions, and speeding up the construction of sewage environmental tax system. The results illustrate that as the proposed method can control the total amount of sewage, it could provide decision-making references for the amelioration of water environment.

miR-877 inhibits the proliferation, migration, and invasion of osteosarcoma cells by targeting gamma-glutamylcyclotransferase.

Gamma-glutamylcyclotransferase (GGCT) can promote the progression of osteosarcoma (OS). MicroRNAs also play significant roles in regulating the progression of OS. This study was designed to investigate whether miR-877 exerts its function in OS by targeting GGCT. The proliferation of OS cells (Saos-2 and U2OS) was detected by MTT and colony formation assays. The migration and invasion of OS cells were detected by transwell assays. The expressions of miRNAs and GGCT were detected by quantitative real-time PCR and Western blot. The luciferase reporter assay was performed to assess whether miR-877 could target GGCT. miR-877 was down-regulated both in OS tissues and OS cell lines (Saos-2 and U2OS). The overexpression of miR-877 inhibited the proliferation, migration, and invasion of OS cell lines, while the knockdown of miR-877 could negate effects. The expression of GGCT was increased in Saos-2 and U2OS cells. miR-877 could target GGCT, and the mRNA level of GGCT in Saos-2 and U2OS cells was decreased by the overexpression of miR-877. miR-877 overexpression inhibited the migration and invasion and suppressed the proliferation of Saos-2 and U2OS cells, and the overexpression of GGCT reversed this effects. The knockdown of miR-877 promoted the migration and invasion and facilitated the proliferation of Saos-2 and U2OS cells, and the silence of GGCT abolished this effects. Our findings suggested that miR-877 could inhibit the proliferation, migration, and invasion of OS cells by targeting GGCT.

Trade-off between equity and efficiency for allocating wastewater emission permits in watersheds considering transaction.

As the management of wastewater emission permits in watershed has become a growing worldwide concern, a substantial challenge has been created in balancing the social stability, economic construction, and ecological function. Therefore, the equitable and efficient allocation of wastewater emission permits in watershed integrating sustainability is vital for environmental management. Considering the wastewater discharge permits transaction between subareas, a multi-objective model is proposed to analyze the allocation of wastewater emission permits in a watershed. The first objective function is to maximize the allocation equity using the environmental Gini coefficient, and the second is to maximize the economic efficiency for the sustainable development of a watershed as the constraint. In this study, the trade-off between the equity and economic efficiency of allocation is balanced. A case study of the Tuojiang River Basin in China is conducted to demonstrate the feasibility, rationality and practicality of the model. The multi-principle and multi-objective allocation model was found to be more reliable and feasible than the previous models, indicating that the equity and efficiency should be balanced to mitigate the water scarcity and deteriorating water quality when managing the basin, and trading is an effective measure for ensuring the equity.

A Soft-Path Solution to Risk Reduction by Modeling Medical Waste Disposal Center Location-Allocation Optimization.

The risk of medical waste pollution and huge demand of daily medical waste disposal pose great difficulties to medical waste management. Establishing medical waste disposal centers (MWDCs) is considered one of the ways to reduce the environmental and public risk of medical waste pollution. However, how to serve the medical waste disposal demand in optimal MWDCs' locations is a key challenge due to the complexity of the whole system and relationships among stakeholders. This article develops a soft-path solution for reducing risks as well as mitigating the related costs by optimizing the MWDC location-allocation problem. A risk mitigation-oriented bilevel equilibrium optimization model is developed for modeling the Stackelberg game behavior between the local government and the medical institutions. The objectives of the local government are minimizing the total risk of loss, the subsidy costs, and the investment cost of building the MWDCs, while minimizing the disposal and transportation costs are the objectives at the medical institution level. Fuzzy random variables are introduced by combining insufficient historical data with expert knowledge via consulting surveys to describe the coexisting uncertainties in the data. To solve the model, a hybrid approach combined with the interactive fuzzy programming technique and an Entropy-Boltzmann selection-based genetic algorithm are designed and tested. The Chengdu Medical Waste Disposal Centers Planning Project is used as a practical application. The results show that it is possible to achieve a balanced market with higher economic efficiency and significantly reduced risk through an appropriate principle of interactive actions between the bilevel stakeholders.

Freshwater microplastics pollution: Detecting and visualizing emerging trends based on Citespace II.

Microplastic particles with less than 5 mm in diameter has been detected in human feces and freshwater systems. Microplastics could cause serious physical and chemical harm to humans and organisms. Some previous studies on microplastics mainly concentrate on the marine environment, but few have focused on freshwater microplastics. Therefore, Citespace II is used to systematically analyze the related literature in order to comprehensively understand the research state of freshwater microplastics. The results show that there is still a large gap between research on freshwater and marine microplastics. Studies on freshwater microplastics have mainly been undertaken in developed countries such as the United States and Germany, while fewer studies have been conducted in the developing countries which face the most serious plastic pollution. Most studies focus on the rivers and lakes, but other freshwater sources with microplastic pollution, such as groundwater and reservoirs, have received less attention. This study also explored the possible opportunities and challenges that may be faced in freshwater research in order to introduce specific policies and measures to mitigate this emerging pollutant.

Efficacy, safety and prognosis of treating neurological deficits caused by spinal tuberculosis within 4 weeks' standard anti-tuberculosis treatment: A single medical center's experience.

The present study aimed to retrospectively analyze the safety and efficacy of the early surgical management of thoracic tuberculosis (TB) in patients with neurological deficits. The medical data of patients with thoracic TB exhibiting neurological deficit in the Chest Hospital of Hebei Province were retrospectively reviewed. A total of 234 cases, including 123 males and 115 females, were recruited in the present study. Their pre- and postoperative neurological deficit and pain levels were assessed using the 2002 American spinal injury association (ASIA) impairment scale and visual analog scale, respectively. Patients were divided into two groups according to whether their preoperative standardized anti-TB treatment time was ≥4 weeks or <4 weeks. There was no difference in blood loss and operation time between the two groups. The erythrocyte sedimentation rate was higher in patients receiving standard anti-TB <4 weeks prior to and 1 month following surgery compared with the ≥4 weeks group, but the difference was not significant 6 months following surgery. ASIA scale scores all increased significantly 1 month following surgery in the <4 weeks group compared with the ≥4 weeks group (P=0.001) though there was no difference between the scores prior to surgery. ASIA scale scores improved to 4.4±0.5 and 4.5±0.4 in patients with anti-TB treatment times of ≥4 weeks and <4 weeks, respectively, 24 months following surgery (P=0.0895). The present study demonstrated that for patients with thoracic TB exhibiting neurological deficit, early surgical management following <4 weeks' standard anti-TB treatment is recommended. It may relieve spinal cord compression and also benefit the early recovery of neurological function in these patients.

Evaluating the oil production and wastewater treatment efficiency by an extended two-stage network structure model with feedback variables.

Oil is an indispensable and important energy source in modern society, and oil production plays a vital role in economic development. However, there is no denying that oil production has a very bad impact on the environment. To realize the sustainable development of oil production, the environmental problems caused by oil production need to be controlled and managed strictly. Aiming at the practical problems of insufficient recoverable reserves of high quality oil and aggravating environmental pollution, efficient oil production and wastewater treatment become more and more important. Therefore, the whole system is divided into two stages. The stage 1 is oil development, and the stage 2 is wastewater treatment. Considering that the model needs to solve the undesirable output, an extended two-stage Slacks-Based Measure (SBM) Data Envelopment Analysis (DEA) network structure model with a feedback variable is established. The efficiency value of each stage can be obtained, and the weakness of each stage can be identified, so that the efficiency value of the whole system is more accurate. And then thirteen oilfields are selected for the numerical analysis to verify the validity and accuracy of the proposed model, the results demonstrate that the overall system is efficient only if the two stages are efficient; the oil production has higher efficiencies than the oilfield wastewater treatment; There is a stronger relationship between the efficiency of oilfield wastewater treatment and the whole system. A comparison with a traditional model demonstrated that the proposed model has a more scientific, stable and practical evaluation methods.

Scale and process design for sewage treatment plants in airports using multi-objective optimization model with uncertain influent concentration.

The treatment of airport sewage has posed many novel challenges because of its huge impact on the surrounding environment. This paper proposes a multi-objective decision model to optimize the scale design and process selection of sewage treatment plants in airports. In this model, we consider the conflict among the process cost, environmental protection, and benefits of recycled water. In addition, the uncertainty in influent concentration and passenger throughput is also incorporated. Airport sewage treatment has its own unique features, such as the concentration of airport sewage is higher than that of ordinary urban sewage, the change in passenger throughput impacts the volume of the airport sewage treatment, and the utilization rate of the entire sewage treatment plant must be higher than or equal to 70%. Only in this case can the airport sewage treatment plant pass the acceptance test. The Tianfu International Airport, the largest civil transportation hub airport project in southwestern China, is used to prove the efficiency of the proposed model. Finally, some significant insights are suggested for the design of wastewater treatment plants in airports.

Equilibrium approach towards water resource management and pollution control in coal chemical industrial park.

In this study, an integrated water and waste load allocation model is proposed to assist decision makers in better understanding the trade-offs between economic growth, resource utilization, and environmental protection of coal chemical industries which characteristically have high water consumption and pollution. In the decision framework, decision makers in a same park, each of whom have different goals and preferences, work together to seek a collective benefit. Similar to a Stackelberg-Nash game, the proposed approach illuminates the decision making interrelationships and involves in the conflict coordination between the park authority and the individual coal chemical company stockholders. In the proposed method, to response to climate change and other uncertainties, a risk assessment tool, Conditional Value-at-Risk (CVaR) and uncertainties through reflecting parameters and coefficients using probability and fuzzy set theory are integrated in the modeling process. Then a case study from Yuheng coal chemical park is presented to demonstrate the practicality and efficiency of the optimization model. To reasonable search the potential consequences of different responses to water and waste load allocation strategies, a number of scenario results considering environmental uncertainty and decision maker' attitudes are examined to explore the tradeoffs between economic development and environmental protection and decision makers' objectives. The results are helpful for decision/police makers to adjust current strategies adapting for current changes. Based on the scenario analyses and discussion, some propositions and operational policies are given and sensitive adaptation strategies are presented to support the efficient, balanced and sustainable development of coal chemical industrial parks.

Processing Technology Selection for Municipal Sewage Treatment Based on a Multi-Objective Decision Model under Uncertainty.

This study considers the two factors of environmental protection and economic benefits to address municipal sewage treatment. Based on considerations regarding the sewage treatment plant construction site, processing technology, capital investment, operation costs, water pollutant emissions, water quality and other indicators, we establish a general multi-objective decision model for optimizing municipal sewage treatment plant construction. Using the construction of a sewage treatment plant in a suburb of Chengdu as an example, this paper tests the general model of multi-objective decision-making for the sewage treatment plant construction by implementing a genetic algorithm. The results show the applicability and effectiveness of the multi-objective decision model for the sewage treatment plant. This paper provides decision and technical support for the optimization of municipal sewage treatment.

Integrated waste load allocation for river water pollution control under uncertainty: a case study of Tuojiang River, China.

This paper presents a bi-level optimization waste load allocation programming model under a fuzzy random environment to assist integrated river pollution control. Taking account of the leader-follower decision-making in the water function zones framework, the proposed approach examines the decision making feedback relationships and conflict coordination between the river basin authority and the regional Environmental Protection Agency (EPA) based on the Stackelberg-Nash equilibrium strategy. In the pollution control system, the river basin authority, as the leader, allocates equitable emissions rights to different subareas, and the then subarea EPA, as the followers, reallocates the limited resources to various functional zones to minimize pollution costs. This research also considers the uncertainty in the water pollution management, and the uncertain input information is expressed as fuzzy random variables. The proposed methodological approach is then applied to Tuojiang River in China and the bi-level linear programming model solutions are achieved using the Karush-Kuhn-Tucker condition. Based on the waste load allocation scheme results and various scenario analyses and discussion, some operational policies are proposed to assist decision makers (DMs) cope with waste load allocation problem for integrated river pollution control for the overall benefits.

Waste load equilibrium allocation: a soft path for coping with deteriorating water systems.

Waste load allocation is always regarded as another efficient approach comparing with the technology-based approach to improve the water quality. This paper proposes a bi-level multi-objective optimization model for optimally allocating the waste load of a river basin incorporating some concerns (i) the allocation equity from the regional authority, (ii) maximal benefits from the subareas along the river, and (iii) the Stackelberg-Nash-Cournot equilibrium strategy between the upper and lower decision makers. Especially, a novel Gini coefficient for measuring the load allocation equity is defined by considering the economic level and waste water quantity. The applicability and effectiveness of the proposed model is demonstrated through a practical case based on the Tuojiang River, which is a typical basin with diversified industrial waste discharges in western China. Some operational suggestions are developed to assist the decision makers' cope with deteriorating water systems.