Predicting impact forces on pipelines from deep-sea fluidized slides:A comprehensive review of key factors

Deep-sea pipelines play a pivotal role in seabed mineral resource development,global energy and resource supply provision,network communication,and environmental protection.However,the placement of these pipelines on the seabed surface exposes them to potential risks arising from the complex deep-sea hydrodynamic and geological environment,particularly submarine slides.Historical incidents have highlighted the substantial damage to pipelines due to slides.Specifically,deep-sea fluidized slides(in a debris/mud flow or turbidity current physical state),characterized by high speed,pose a significant threat.Accurately assessing the impact forces exerted on pipelines by fluidized submarine slides is crucial for ensuring pipeline safety.This study aimed to provide a comprehensive overview of recent advancements in understanding pipeline impact forces caused by fluidized deep-sea slides,thereby identifying key factors and corresponding mechanisms that influence pipeline impact forces.These factors include the velocity,density,and shear behavior of deep-sea fluidized slides,as well as the geometry,stiffness,self-weight,and mechanical model of pipelines.Additionally,the interface contact conditions and spatial relations were examined within the context of deep-sea slides and their interactions with pipelines.Building upon a thorough review of these achievements,future directions were proposed for assessing and characterizing the key factors affecting slide impact loading on pipelines.A comprehensive understanding of these results is essential for the sustainable development of deep-sea pipeline projects associated with seabed resource development and the implementation of disaster prevention measures.

Effects of Transgenic Bt+CpTI Cotton Cultivation on Functional Diversity of Microbial Communities in Rhizosphere Soils

[Objective] This study aimed to investigation the effects of tranagenic Bt ＋ CpTI cotton cultivation on functional diversity of microbial communities in rhizospbere soils. E Method] By using the Biolog method, a comparative study was conducted on the utilization level of single carbon source by microbes in the rhi- zosphere soils of transgenic Bt ＋ CpTI cotton sGK321 and its parental conventional cotton ＇ Shiyuan 321＇ at different growth stages. [ Result ] The results showed that, compared with the parental conventional cotton, the average well-color development （AWCD） value of micmhial communities in rhizospbere soils of transgenie Bt ＋ CpTI cotton were significantly higher （P 〈 O. 05） at seedling stage and budding stage while significantly lower at flower and boll stage and bell opening stage. Shannon-Wiener diversity index （H） and Simpson dominance index （D） of microbial communities in rhlzesphere soils of transgenic cotton and conventional cotton varied with the different growth stages, whereas the Shannon-Wiener evenness index （E） showed no significant difference between transgenie cotton and convention- al cotton at four growth stages. Principal component analysis indicated that the patterns of carbon source utilization by microbial communities in rhizospbere soils were similar among transgenic cotton at seeding stage and flower and boll stage and parental conventional cotton at seeding stage and budding stage, which were also similar between tranagenic cotton at budding stage and parental conventional cotton at flower and boll stage. [ Conclusion] Analysis of different carbon sources indi- cated that the main carbon sources utilized by soil microbes were carbohydrates, amino acids, carboxylie acids and polymers.

Review of Hydrogen Embrittlement in Metals: Hydrogen Diffusion, Hydrogen Characterization, Hydrogen Embrittlement Mechanism and Prevention

Hydrogen dissolved in metals as a result of internal and external hydrogen can affect the mechanical properties of the metals, principally through the interactions between hydrogen and material defects. Multiple phenomena such as hydrogen dissolution, hydrogen diffusion, hydrogen redistribution and hydrogen interactions with vacancies, dislocations, grain boundaries and other phase interfaces are involved in this process. Consequently, several hydrogen embrittlement(HE) mechanisms have been successively proposed to explain the HE phenomena, with the hydrogen-enhanced decohesion mechanism, hydrogenenhanced localized plasticity mechanism and hydrogen-enhanced strain-induced vacancies being some of the most important. Additionally, to reduce the risk of HE for engineering structural materials in service, surface treatments and microstructural optimization of the alloys have been suggested. In this review, we report on the progress of the studies on HE in metals, with a particular focus on steels. It focuses on four aspects:(1) hydrogen diffusion behavior;(2) hydrogen characterization methods;(3) HE mechanisms;and(4) the prevention of HE. The strengths and weaknesses of the current HE mechanisms and HE prevention methods are discussed, and specific research directions for further investigation of fundamental HE mechanisms and methods for preventing HE failure are identified.

Identification and assessment of environmental burdens of Chinese copper production from a life cycle perspective

The environmental burdens of Chinese copper production have been identified and quantified in the context of typical technologies, materials supplies and environmental emissions by a life cycle approach. Primary and secondary copper production using copper ores and scraps, respectively, were analyzed in detail. The flash and bath smelting approaches and the recycling of copper scraps were selected as representative copper production processes. A quantitative analysis was also conducted to assess the influence of material transport distance in copper production. Life cycle assessment （LCA） results showed that resources depletion and human health contribute significantly to environmental burdens in Chinese copper production. In addition, the secondary copper production has dramatically lower environmental burdens than the primary production. There is no obvious distinction in overall environmental burdens in primary copper production by flash or bath smelting approach. However, resources depletion is lower and the damage to human health is higher for flash smelting approach. Ecosystem quality damage is slight for both approaches. Environ- mental burdens from the mining stage contribute most in all life cycle stages in primary copper production. In secondary copper production, the electrolytic refining stage dominates. Based on the life cycle assessment results, some suggestions for improving environmental performance were proposed to meet the sustainable development of Chinese copper industry.

Hydrogen embrittlement and failure mechanisms of multi-principal element alloys:A review

Multi-principal element alloys exhibit excellent physical,chemical and mechanical properties,and they are used as novel structural materials for potential applications in nuclear energy,hydrogen energy,and petrochemical fields.However,exposing components made of the alloys to service conditions related to the mentioned applications may induce hydrogen embrittlement(HE)as one of the typical failure mechanisms.In this review,we report and summarize the progress in understanding HE in multi-principal element alloys,with a particular focus on high-entropy alloys(HEAs).The review focuses on four aspects:(1)hydrogen migration behavior(hydrogen dissolution,hydrogen diffusion,and hydrogen traps);(2)factors affecting HE(hydrogen concentration,alloy elements and microstructure);(3)tensile mechanical properties in the presence of hydrogen and micro-damage HE mechanisms;(4)the design concept for preventing hydrogen-induced mechanical degradation.The differences in the HE behavior and failure mechanisms between HEAs and traditional alloys are compared and discussed.Moreover,specific research directions for further investigation of fundamental HE issues and a strategy for a simultaneous improvement in strength and HE resistance are identified.

双吡啶含钴离子液体的制备及耦合过硫酸盐催化脱硫

采用两步法制备di-[EtPy]/[CoCl_(3)]离子液体为催化剂,并利用核磁共振波谱(HNMR)、傅里叶红外光谱仪(FT-IR)、热重分析仪(TG)和扫描电子显微镜(SEM-Mapping-EDS)等仪器对催化剂进行表征。本研究以di-[EtPy]/[CoCl_(3)]为催化剂、过硫酸盐(PMS)为氧化剂、乙腈为萃取剂构建一套萃取催化氧化脱硫体系,对正辛烷中的二苯并噻吩(DBT)进行脱除。不仅考察了催化剂的制备,还探究了催化剂的催化性能、脱硫性能以及影响脱硫的主要因素。研究表明,在初始含硫浓度为609 mg/kg的模拟油加入量为6 g,di-[EtPy]/[CoCl_(3)]投加量为0.10 g,PMS (20wt%)投加量为0.50 g,萃取剂乙腈投加量为1.00 g,体系反应温度45.0℃以及反应时长70 min条件下,模拟汽油的脱硫率为96.86%。di-[EtPy]/[CoCl_(3)]循环使用5次后,脱硫率仍能达到86.00%。由于氧化产物经气相色谱-质谱联用仪(GC-MS)表征为二苯并噻吩砜(DBTO_(2)),本研究结合实验结果对氧化过程机理进行了分析和推测。

Comparison on End-of-Life strategies of WEEE in China based on LCA

As the Electrical and Electronic Equipment （EEE） are upgraded more frequently in China, a large quantity of Waste Electrical and Electronic Equipment （WEEE） was and will be generated. It becomes an urgent issue to develop and adopt an effective End-of-Life （EoL） strategy for EEE in order to balance the resource recovery and environmental impacts. In an EoL strategy hierarchy for EEE, reuse strategy is usually deemed to be prior to materials recovery and other strategies. But in practice, the advantages and disadvantages of different strategies are always context-dependent. Therefore, main EoL strategies for EEE in China need to be evaluated in environment and resources aspects from the life cycle perspective. In this study, the obsolete refrigerator and Power Supply Unit （PSU） ofdesktop PC are both taken as the target products. Life Cycle Assessment （LCA） is applied to assess the environmental impacts of different EoL scenarios in China： Unit Reuse Scenario （URS）, Component Reuse Scenario （CRS） and Materials Recovery Scenario （MRS）. The LCA results show that the EoL strategies hierarchy is reasonable for the part＇of computer, bui not necessarily suitable for obsolete refrigerators. When the policy makers promote or demote one EoL strategy especially reuse, it is necessary to take subsequent impacts into consideration.

Magnetic properties,crystalline and magnetic microstructures of dual-main-phase(Nd,Ce)-Fe-B sintered magnets

The(Nd,Ce)-Fe-B sintered magnets were prepared by a dual-main-phase(DMP)process under the same conditions using different combinations of Nd-Fe-B with Ce-Fe-B and(Nd,Ce)-Fe-B strips.The crystalline and magnetic microstructures of DMP(Nd,Ce)-Fe-B magnets with the remanence of 11.92-12.68 kGs,the intrinsic coercivity of 3.97-5.31 kOe,and the maximum energy product of 23.08-32.99 MGOe have been investigated.Magnetic force microscope(MFM)investigations reveal that the DMP(Nd,Ce)-Fe-B magnets show maze-like patterns,which are like that of standard anisotropy Nd-Fe-B sintered magnets by and large.However,much finer domain structures mixing with coarse ones can be observed obviously in DMP(Nd,Ce)-Fe-B sintered magnets.The size distribution of the domain width of the DMP(Nd,Ce)-Fe-B magnet is not uniform obviously.The average domain width is W=0.912μm,and the fine domain width has only 0.216μm.The smaller domain width and more branch domain patterns exist in poorer coercivity DMP magnets.This is caused by the non-uniform Ce composition of poorer property DMP magnets and the grain boundary microstructure that is not conducive to improving the coercivity.Furthermore,it is found that some domains of rare-earth-rich grain boundary phases exhibit the characteristics of plate-like patterns rather than no-contrast by using MFM,indicating their ferromagnetism.Obvious correlations between the crystalline microstructure,chemical composition of phases,and magnetic structure were demonstrated for the DMP magnets.

An updated review and conceptual model for optimizing WEEE management in China from a life cycle perspective

Waste electrical and electronic equipment （WEEE） is a rapidly growing category of solid waste. China is now facing WEEE problems from both growing domestic generation and illegal imports. Currently, the amount of WEEE formally treated has increased steadily in China. The layout of the formal sector has been basically completed. Meanwhile, by controlling illegal disassembly activities, the informal sector has been gradually transformed to formal one. Beginning with the overview of the WEEE recycling industry in China, this paper first lists the latest progress in WEEE management from such aspects as the new edition of China RollS Directive （Restriction of Hazardous Substances Directive）, the updated WEEE Treatment List, the updated WEEE fund standard, the revised National Hazardous Waste List, and a brand-new plan on extended producer responsibility. In so doing, we elucidate the current challenges on WEEE management in detail： the imbalance between fund levies and subsidies, the gap in the supervision scope, the homogenization of recycling industry and the lack of life cycle approaches. Finally, a conceptual framework for integrated management of WEEE is proposed from a life cycle perspective. Overall, the life cycle management of WEEE includes three aspects： developing life cycle information for decision-making, implementing life cycle engineering with life cycle tools, and improving WEEE legislation based on life cycle thinking. By providing specific operating strategies, this life cycle framework should help to optimize WEEE management in developing countries where legislation is imperfect and the recycling system is relatively immature.