Cycle Operation Research Articles

Nanocomposites of Conducting Polymers and 2D Materials for Flexible Supercapacitors.

Flexible supercapacitors (FSCs) with high electrochemical and mechanical performance are inevitably necessary for the fabrication of integrated wearable systems. Conducting polymers with intrinsic conductivity and flexibility are ideal active materials for FSCs. However, they suffer from poor cycling stability due to huge volume variations during operation cycles. Two-dimensional (2D) materials play a critical role in FSCs, but restacking and aggregation limit their practical application. Nanocomposites of conducting polymers and 2D materials can mitigate the above-mentioned drawbacks. This review presents the recent progress of those nanocomposites for FSCs. It aims to provide insights into the assembling strategies of the macroscopic structures of those nanocomposites, such as 1D fibers, 2D films, and 3D aerogels/hydrogels, as well as the fabrication methods to convert these macroscopic structures to FSCs with different device configurations. The practical applications of FSCs based on those nanocomposites in integrated self-powered sensing systems and future perspectives are also discussed.

Integrated Sustainability Assessment of Electric Bus Adoption: A Comprehensive Model for Ecological, Economic, and Operational Impact

The spread of electric stations in cities around the world is an important step towards sustainable urban transportation. In Task 1,We developed the FE-VC model to determine carbon emission indicators based on the BWM approach, and demonstrated the ecological consequences over the life cycle through quantitative models. In the quantitative calculation of urban data, compared with diesel buses, the carbon emission reduction rate of pure electric buses is 28.68%, mainly from the fuel cycle, in which the carbon emission reduction rate of the fuel cycle stage is as high as 40.11%, and it takes about 3.5 years to achieve the relative carbon emission reduction. In Task 2, we construct an economic impact consequence model based on the time value of capital with the theory of time value of money as the core, consider the full life cycle of acquisition, operation and vehicle maintenance, quantify and visualize the impact mechanism of electric buses on the economy, and provide a method to understand the economic impact for metropolitan areas. For task 3, based on the optimal enterprise operating cost and the optimized economic impact model, we construct the initial replacement model of the electric bus. The initial replacement model was optimized by simplifying the social cost of carbon emission, and an electric bus replacement model based on the optimal enterprise operating cost was obtained. In city-specific applications, we find that vehicle choice has a significant impact on fleet replacement plans and operating costs, and that using multiple vehicles can significantly reduce operating costs as electrification rates increase.

Organic-Inorganic Hybrid Synaptic Transistors: Methyl-Silsesquioxanes-Based Electric Double Layer for Enhanced Synaptic Functionality and CMOS Compatibility.

Electrical double-layer (EDL) synaptic transistors based on organic materials exhibit low thermal and chemical stability and are thus incompatible with complementary metal oxide semiconductor (CMOS) processes involving high-temperature operations. This paper proposes organic-inorganic hybrid synaptic transistors using methyl silsesquioxane (MSQ) as the electrolyte. MSQ, derived from the combination of inorganic silsesquioxanes and the organic methyl (-CH3) group, exhibits exceptional thermal and chemical stability, thus ensuring compatibility with CMOS processes. We fabricated Al/MSQ electrolyte/Pt capacitors, exhibiting a substantial capacitance of 1.89 µF/cm2 at 10 Hz. MSQ-based EDL synaptic transistors demonstrated various synaptic behaviors, such as excitatory post-synaptic current, paired-pulse facilitation, signal pass filtering, and spike-number-dependent plasticity. Additionally, we validated synaptic functions such as information storage and synapse weight adjustment, simulating brain synaptic operations through potentiation and depression. Notably, these synaptic operations demonstrated stability over five continuous operation cycles. Lastly, we trained a multi-layer artificial deep neural network (DNN) using a handwritten Modified National Institute of Standards and Technology image dataset. The DNN achieved an impressive recognition rate of 92.28%. The prepared MSQ-based EDL synaptic transistors, with excellent thermal/chemical stability, synaptic functionality, and compatibility with CMOS processes, harbor tremendous potential as materials for next-generation artificial synapse components.

Scientific and Methodological Approach to Assessing Timeliness Operational Management of Vehicle Routing in an Urban Agglomeration

Purpose of reseach. The purpose of this article is to develop a scientific and methodological approach to assessing the timeliness of decision-making in the operational management of car traffic routing in an urban agglomeration. Timeliness is manifested in reducing the time to prepare a decision to change the route of a car delivering goods in conditions of a possible (predicted) increase in traffic congestion at intersections and streets crossing the established route in an urban agglomeration. Methods. The presented approach is based on the basic principles of management theory in organizational systems, the theory of rational consumer behavior, mathematical statistics, and simulation modeling.Results. A variant of the generalized scheme of the operational control cycle for the routing of a car in an urban agglomeration has been developed. A sequence of estimation of decision-making time for operational control of vehicle traffic routing is proposed, and the individual stages of the evaluation sequence implement the main functions of the developed version of the operational control cycle. Experimental dependences of the time of analysis of route parameters during operational management on the quantity and quality of the routes under consideration in the AnyLogic 8.4.0 simulation environment are obtained.Conclusion. The article considers an approach to assessing the timeliness of decision-making in the operational management of the route of a car delivering goods in an urban agglomeration. To minimize the time for making an operational decision, it is proposed to predict the intensity of traffic congestion and assess the quality of the route. The approach allows, based on forecasting the state of the road situation at the intersection points of the route and streets with a high probability of traffic congestion, as well as, taking into account the number and quality of routes, to increase the timeliness of making a decision to change the route of a car delivering goods to an urban agglomeration.

Efficient separation for yttrium and heavy rare earth elements using functionalized quaternary ammonium ionic liquids

Given the similar ionic radii of heavy rare earth elements (HREEs), sixteen functionalized ionic liquids (FILs) with potential extraction and separation properties were designed and prepared, also their feasibilities for yttrium (Y) separation from HREEs were evaluated. The results show that [N16MOP][HDA] is the optimal extractant for Y separation from other HREEs, achieving a Ho/Y separation factor of 2.82. The extraction reaction is based on an ion pair mechanism, where a HoCl3 molecule is extracted by two [N16MOP][HDA] molecules. Complete stripping of the loaded rare earth elements (REEs) can be achieved using 0.1 mol/L hydrochloric acid. Deionized water is used as a scrubbing agent, the average separation coefficient between Y and other HREEs during the scrubbing process is 2.5. After six cycles of continuous operation for 15 h, the organic phase maintains stable extraction and separation capabilities, demonstrating good recyclability and periodic stability. This study introduces a sustainable method for separating Y from HREEs using novel FILs, which is more efficient and consumes fewer chemical reagents. The results of this study indicate that the introduction of functionalized cation in FIL enhances the affinity and selectivity of HREEs. This provides valuable insights into the design of FIL-based extractents and their potential applications in sustainable rare earth separation.

Photo-thermoelectric effect-driven detection of optical communication light in graphene/hBN heterostructures

We report on the photodetection properties of high-quality graphene encapsulated by hexagonal boron nitride under illumination with optical communication light. We demonstrate a gate-tunable photocurrent and zero-bias switching cycle operation at RT. Through gate and temperature-dependent photocurrent measurements, we determine that the dominant photoresponse mechanism is the photo-thermoelectric effect. At low temperatures, the photocurrent in finite doping regions correlates with the Seebeck coefficient, while sharp peaks emerge near the charge neutrality point due to an edge-excited photocurrent. Our study provides guidelines for high-performance graphene-based optoelectronic devices.

Моделирование и оценка интенсивности старения моторного масла в судовых тронковых дизелях при их наддуве

A computational and experimental model of the aging of lubricating oil in different directions is presented, taking into account the influence on the intensity of its degradation of the degree of forcing (thermal load) and the technical condition of diesel, the quality (motor group) of the lubricant product and the sulfur content in the fuel. The novelty in assessing the aging of the lubricant in a tank diesel engine when forcing it by supercharging consists in the formation of a thermal load on the oil film, which determines the aging rate of the engine oil on the cylinder sleeve of the engine. It is reported how the density of the heat flux acting on the surface of the oil film swept by the piston is experimentally fixed and averaged over the height of the sleeve and the angle of rotation of the crankshaft during the engine operating cycle. The influence of the factors under consideration on the specific rate of aging of lubricating oil per unit area of the sleeve surface in contact with gases in the direction of additive activation, decrease in alkalinity, increase in acidity, tar formation and accumulation of insoluble products has been identified. The lines of equal values of the hypersurfaces of the response functions for the specific intensity of the alkalinity response and the formation of insoluble products of tar formation and acidity growth are illustrated. The requirements for engine oil have been formed according to the level of alloying with multifunctional additives, depending on the degree of boost (average effective pressure) of supercharged marine tank diesels. As a result of the analysis of the aging rate of engine oil in modern marine diesel engines with medium and high boost, the expediency of using unified type oils in them has been confirmed M-10(14)G2CS and M-14(16)DCL20 with multifunctional additives MASK and PMS for the combustion of distillate fuels and their mixtures with fuel oils with a sulfur content of up to 0.5%.

Neutronic design of small modular long­life pressurized water reactor using thorium carbide fuel at a power level of 300–500 MWth

This study presents the neutronic design of a small modular long­life Pressurized Water Reactor (PWR) using thorium carbide fuel with 233U fissile material. The target optimization for this study is a reactor designed to operate for 20 years, with excess reacti­vity throughout the reactor operational cycle consistently below 1.00 % dk/k. The analysis involves dividing the reactor core into three fuel regions with 233U enrichment levels ranging from 3 % to 8 %, with a 1 % difference for each fuel region. To achieve optimum conditions, 231Pa was randomly added to the fuel. The fuel volume fraction in this design varied from 30 % to 65 %, with a 5 % incremental variation. Power level variations are also studied within the 300–500 MWth with increments of 50 MWth. Calculations were performed using the Standard Reactor Analysis Code (SRAC) program with the PIJ and CITATION modules for cell and core calculations utilizing JENDL­4.0 nuclide data. Neutronic calculations indicate that the fuel with a 60 % volume fraction achieves optimum conditions at a power level of 300 MWth. The best performance was observed with a fuel volume fraction of 65 %, reaching optimum conditions across power levels ranging from 300 to 500 MWth. For the fuel with the best performance, the power density distributions for low and high power levels follow the same pattern radially and axially. The power peaking factor (PPF) for all fuel configurations approaching the optimum conditions remains below two, a safe limit for the PWR. Other neutronic safety parameters, such as the Doppler coefficient and void fraction coefficient, also stay within the safe limits for the PWR, with both values remaining negative throughout the reactor operational cycle

The role of sheet-like TiO2 in polyamide reverse osmosis membrane for enhanced removal of endocrine disrupting chemicals

Thin film composite (TFC) reverse osmosis (RO) membrane shows good promise for treating wastewater containing endocrine disrupting chemical (EDC) pollutants. The incorporation of functional materials with exceptional structural and physico-chemical properties offers opportunities for the membranes preparation with enhanced permselectivity and better antifouling properties. The present study aims to improve the EDC removal efficiency of TFC RO membrane using two-dimensional titania nanosheets (TNS). RO membrane was prepared by incorporating TNS in the dense layer of polyamide (PA) layer to form thin film nanocomposite (TFN) membrane. The TNS loading was varied and the influences on membrane morphology, surface hydrophilicity, surface charge, as well as water permeability and rejection of EDC were investigated. The results revealed that the inclusion of TNS in the membrane resulted in the increase of water permeability and EDC rejection. When treating the mixture of bisphenol A (BPA) and caffeine at 100 ppm feed concentration, the TFN membrane incorporated with 0.05% TNS achieved water permeability of 1.45 L/m2·h·bar, which was 38.6% higher than that of unmodified TFC membrane, while maintaining satisfactory rejection of >97%. The enhancement of water permeability for TFN membrane can be attributed to their hydrophilic surface and unique nanochannel structure created by the nanoscale interlayer spacing via staking of TiO2 nanosheets. Furthermore, the 0.05TFN membrane exhibited excellent fouling resistance towards BPA and caffeine pollutants with almost 100% flux recovery for three cycles of operations.

Installation and test procedure for frequency stability under cyclic loading of metals and alloys

Manufacture of parts operating under difficult conditions of cyclic loading, as well as products with stable dimensions necessitates the use of materials with minimal manifestations of inelastic properties. Study of these materials suggests conducting specialized narrowly focused tests using newly developed machines and installations with appropriate experimental techniques. We present the design, operation and control features of the original electromagnetic installation for testing fatigue and frequency stability and operating in a self- oscillating mode, which provides the equality of the frequency of cyclic loading and natural frequency of the sample. The system of the installation control contains two closed circuits: for excitation of self-oscillations and for stabilization of the oscillation amplitude. The sample is loaded by electromagnetic force, and unloading occurs due to the elastic forces of the material. The methodology and algorithms for calculating the stresses of samples of various geometric shapes for estimating changes in amplitude-frequency characteristics are presented. The calculated relationship between the force applied to the sample and its movement at the point of application of force is derived with subsequent determination of the stress by a known force. The results of calibration tests for the static mode of sample loading are presented and the forces acting on the sample (external, inertia, and elastic forces) are evaluated taking into account the maximum stress and maximum strain amplitude. Static and cyclic loading modes are compared. The frequency characteristics obtained during testing steel samples according to the proposed method are obtained. The experimental results of tests with interruptions in the process of cyclic loading and continuous testing are analyzed. It is shown that interruptions in cyclic tests lead to a jump-like increase in the frequency, whereas continuous tests revealed no jumps. At the same time, a comparative analysis with the results of continuous tests showed that the overall frequency deviation is approximately the same for the entire operating cycle in both cases. It is shown that an increase in the frequency after rest is random and does not depend on the number of operating cycles.

Implementation of Building Information Modeling Technologies in Wood Construction: A Review of the State of the Art from a Multidisciplinary Approach

This research raises questions about the possibilities and options of using the BIM methodology associated with software for the wood design and construction of structure modeling along an asset’s cycle life. Likewise, several academic and research initiatives are reviewed. In this sense, this paper aims to establish an appropriate link between two agendas that the architecture, engineering, and construction (AEC) industry, academia, and governments normally handle separately. By conducting several literature reviews (book, journals, and congresses) and extensive software tests (BIM software: Revit v2023, Archicad v27, Tekla, and wood plug-ins: AGACAD, Archiframe, Timber Framing 2015, WoodStud Frame, etc.), the state-of-the-art was assessed in both fields, and several cases linking BIM and wood are shown in detail and discussed. Various theoretical samples are modelled and shown, and the advantages and disadvantages of each technique and stage are explained. On the other hand, although wood construction has been most common for hundreds of years, this is not the case of BIM software developments associated with this materiality. Furthermore, since the appearance of materials such as steel and reinforced concrete, all software developments have focused on these materials, leaving aside the possibility of developing applications for use in wood projects. According to that previously discussed, it can be concluded that BIM for wood has been used more frequently in academia, that both fields have several common processes, and, in many cases, that only a few BIM-wood tools have been used, thus disregarding the high potential and high level of benefits that result with the application of these methodologies for the complete building life cycle (design, construction, and operation).

Tropical Modeling of Battery Swapping and Charging Station

We propose and investigate a queueing model of a battery swapping and charging station (BSCS) for electric vehicles (EVs). A new approach to the analysis of the queueing model is developed, which combines the representation of the model as a stochastic dynamic system with the use of the methods and results of tropical algebra, which deals with the theory and applications of algebraic systems with idempotent operations. We describe the dynamics of the queueing model by a system of recurrence equations that involve random variables (RVs) to represent the interarrival time of incoming EVs. A performance measure for the model is defined as the mean operation cycle time of the station. Furthermore, the system of equations is represented in terms of the tropical algebra in vector form as an implicit linear state dynamic equation. The performance measure takes on the meaning of the mean growth rate of the state vector (the Lyapunov exponent) of the dynamic system. By applying a solution technique of vector equations in tropical algebra, the implicit equation is transformed into an explicit one with a state transition matrix with random entries. The evaluation of the Lyapunov exponent reduces to finding the limit of the expected value of norms of tropical matrix products. This limit is then obtained using results from the tropical spectral theory of deterministic and random matrices. With this approach, we derive a new exact formula for the mean cycle time of the BSCS, which is given in terms of the expected value of the RVs involved. We present the results of the Monte Carlo simulation of the BSCS’s operation, which show a good agreement with the exact solution. The application of the obtained solution to evaluate the performance of one BSCS and to find the optimal distribution of battery packs between stations in a network of BSCSs is discussed. The solution may be of interest in the case when the details of the underlying probability distributions are difficult to determine and, thus, serves to complement and supplement other modeling techniques with the need to fix a distribution.

Exergy efficiency and thermocline degradation of a packed bed thermal energy storage in partial cycle operation: An experimental study

To enable the exploitation of the industry sectors’ huge waste heat potential this study investigates the utilization of packed bed thermal energy storage systems for the waste heat recovery in the iron and steel industry. The main goal is to assess the partial cycle operation of a packed bed thermal energy storage with industrial exhaust gas that is contaminated with high amounts of metal powder. A continuously rising accumulation of powder particles inside the packed bed requires the storage to be charged from the bottom in order to facilitate the removal of powder hold-up. Therefore, investigations focus on the dependency of the thermal performance of the storage on the flow direction of heat transfer fluid during charging/discharging. Exergy efficiency and thermocline degradation are evaluated as key performance indicators for different flow directions of the heat transfer fluid using a lab-scale test rig. Results show that, compared to charging from the top, a slightly faster thermocline degradation occurs for a storage that is charged from the bottom. Still, energy and exergy efficiencies in partial cycle operation are well above 85% and 80% respectively regardless of the heat transfer fluid flow direction. The thermal power rate during discharging is stable between 74% and 93% with respect to the maximum input rate for both charging the storage from the top and from the bottom. All in all, packed bed thermal energy storage systems are found to be suitable for waste heat recovery in industrial processes. Only a marginal deterioration of the thermal performance of the storage has to be expected if the storage is required to be charged from the bottom.

An Efficient 3D-Printed Gravity Mixer for Lab-on-a-CD Applications.

We introduced a new, highly efficient, and uncomplicated mixing device for centrifugal microfluidic platforms, called the gravity mixer. The gravity mixer featured a slope channel that can precisely and sequentially control micro-volume liquids using centrifugal, capillary, and gravitational forces to achieve the desired mixing effect. By adjusting the angular velocity, micro-volumes of liquids in the slope channel of the gravity mixer could be precisely controlled across a wide range. We evaluated the change in mixing efficiency by varying the slope geometry, including the slope angle and the number of mixing cycles. Our study of gravity mixers with different slope angles revealed that the 80° angle gravity mixer achieved the best mixing efficiency, with a standard deviation of 2.39. Additionally, the mixing process in the gravity mixer is highly repeatable, achieving the desired mixing efficiency after only three cycles of operation. Our gravity mixer design and implementation can facilitate the development of more complex 3D-printed lab-on-chip devices.

Eco-efficiency of power supply systems for offshore platforms

This study compared from an Eco-efficiency point of view three electricity supply alternatives for oil and gas extraction, preliminary treatment, and distribution activities that occur on floating production, storage, and offloading platforms (FPSO) operated off the coast of Brazil. The performance of autonomous systems (AS), in which independent open-cycle gas turbines generate electricity, was confronted with those achieved, respectively, by a Power Hub (PH) system and by an arrangement that associates the Power Hub system with an offshore wind farm (PHWE). The environmental dimension of the Eco-efficiency indicator was specified based on applying the Life Cycle Assessment technique for the impact categories of Global Warming Potential, Primary Energy Demand, and Fine Particulate Matter Formation. The economic dimension followed a similar approach based on Life Cycle costing (LCC) when considering the same units' construction, operation, maintenance, and dismantling costs. Given the characteristics of Brazilian oil fields, a comparison was made for three different stages of the operation cycle: C1: maximum extraction of oil and gas; C2: equity of volumes extracted from fuels and water + CO2; and C3: minimal extraction, but economically viable, of fuels. The results indicated that the PH and PHWE systems accumulate better environmental performance than the AS system, particularly regarding Global Warming Potential (35 % and 55 %, respectively) and Fine Particle Matter Formation (47 % and 59 % reduction). However, more than these gains are needed to compensate for the same systems' construction, operation, and maintenance investments, which were increased by up to 76 % in the case of PHWE. The study also concluded that the PH technology and its variation involving wind electrification are promising but that research efforts should be made to reduce costs. These results provide elements that can both subsidize designers from O&G companies in developing new extraction technologies and support decision processes conducted by other stakeholders and policy formulators linked to this segment.

Experimental Investigation of a Pulsation Reactor via Optical Methods

Material treatment in pulsation reactors (PRs) offers the potential to synthesize powdery products with desirable properties, such as nano-sized particles and high specific surface areas, on an industrial scale. These exceptional material characteristics arise from specific process parameters within PRs, characterized by the periodically varying conditions and the resulting enhanced heat and mass transfer between the medium and the particulate material. Understanding flame behavior and the re-ignition mechanism is crucial to controlling the efficiency and stability of the pulse combustion process. In order to accomplish this objective, an investigation was conducted into flame behavior within the combustion chamber of a Helmholtz-type pulsation reactor. The study was focused on primarily analyzing the flame propagation process and examining flame velocity throughout the operational cycle of the reactor. Two optical methods—natural flame luminosity (NFL) and particle image velocimetry (PIV)—were applied in related experiments. An analysis of the NFL measurement data revealed a correlation between the intensity of light emitted by the pulsed flame and the air-fuel equivalence ratio (range from 0.89 to 2.08 in this study). It is observed that a lower air-fuel equivalence ratio leads to higher flame luminosity in the PR. In addition, in order to study the parameters related to system stability and energy transfer efficiency, this study also focuses on the local velocity field measurement method and an example of a fluid flow result in a combustion chamber by using a phase-locked PIV measurement system upgraded from a classic PIV system. The presented results herein contribute to the characterization of flame propagation within a pulsation reactor, as well as in pulsatile flows over one working cycle in a broader context, with flow velocity in the center of the combustion chamber ranging from 1.5 m/s to 5 m/s. Furthermore, this study offers insights into the applicable experimental methodologies for investigating the intricate interplay between flames and flows within combustion processes.

Design and variable scale optimization of flare gas recovery process for hydrogen production

Flare systems are equipped in refining and petrochemical industries to ensure operation safety. However, flare gas sent directly to the flare system for combustion wastes energy and pollutes the environment, so it is of great significance to recover and comprehensively utilize flare gas. A new process of hydrogen production with flare gas recovery is proposed in this paper, which not only solves the problem of environmental pollution but also makes rational use of energy and improves economic benefit. Firstly, the flare gas recovery process for hydrogen production is designed by coupling the poly-refrigerant integrated cycle operation method with the chemical looping combustion sorption enhanced steam methane reforming method. Secondly, key parameters such as reactor temperature, H2O/CH4 molar ratio, and CaO/CH4 molar ratio are optimized through sensitivity analysis with CH4 conversion, H2 yield, H2 purity (dry basis), and CO2 capture rate as indicators. Thirdly, computational fluid dynamics simulation is carried out to validate the above macroscopic analysis results and further optimize the process at the mesoscopic level. The effects of different bed heights on hydrogen purity are analyzed to determine the optimal bed height for the reformer reactor, which strengthens the performance of the equipment. Finally, the process is probed by an economic analysis, which shows that 68.7 tons/year of hydrogen is produced when the recovery of methane from flare gas reaches 137.3 tons/year. This determines the economic feasibility of the process. The significance of this paper lies in: a novel green process using flare gas recovery to produce high-purity hydrogen with the conversion from waste gas to new energy realized with the concept of “turning waste into treasure”; a new way of combining meso-level and macro-level, variable-scale optimization of the process parameters; the recycling of other short-chain hydrocarbon-containing waste gases.

Environmental Risk Assessment of a Hydrocracker Unit in Abadan Oil Refinery Using the EFMEA Analysis

Background: The aim of risk assessment is to use a rational method to analyze risks and to identify the possible hazards and outcomes for people, equipment, materials, and the environment. Methods: The criteria and indices for assessing the environmental, health, and safety risks of the hydrocracker unit were determined by a Delphi questionnaire in this study. Then, an Environmental Failure Mode and Effects Analysis was applied to evaluate, score, and rank the risks based on their probability of occurrence, severity, probability of detection, extent of pollution, and potential of recycling. Results: According to the results of the Delphi process, 19 out of the 22 items were identified as the main criteria in the environmental, health, and safety risk evaluation of the hydrocracker unit at the Abadan Oil Refinery. However, the results indicated that 67% of the risks associated with the life cycle operation were low while 33% of them were high in terms of intensity. In contrast, 75% of the risks associated with control room operators were low and 25% were high in terms of intensity. On the other hand, 64, 7, and 29% of the risks associated with the activities of site employees were low, moderate, and high in terms of intensity, respectively, while the corresponding figures were 14, 29, and 57% in the case of risks associated with repairs. Conclusion: Based on the results of techniques of environmental failure modes and effects analysis (EFMEA) and Delphi, appropriate methods can be used to identify and reduce risks in similar industries.

Polynorepinephrine-regulated filler sulfonation toward interfacial reformation and conductive promotion of nanocomposite proton exchange membrane

Interfacial compatibility between filler and matrix substantially affects the overall morphology and performance of nanocomposites. Compared with bare montmorillonite (MMT), surface modified product such as sulfonated MMT (SMMT) has been known to render optimized interfacial compatibility in composite proton exchange membranes (PEMs) for proton exchange membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs). Nevertheless, in-depth understanding and investigation on the sulfonation of MMT are seldom focused, such as uniformity and sufficiency. Herein, these broadly neglected issues are proposed and resolved using an exemplary polynorepinephrine (PNE)-regulated SMMT (SNMMT). Rather than direct sulfonation utilizing the inherent hydroxyl groups of MMT, a PNE coating with ample hydroxyl groups is deposited on MMT beforehand, which results in more homogeneous and sufficient sulfonation of SNMMT. Compared with normal SMMT, this alteration on surficial geography of filler functionalization brings significant benefits when composited with Nafion matrix, including harmonized filler-matrix compatibility, improved mechanical stability and enhanced proton conduction. Moreover, the antioxidative ability of PNE layer enables improved chemical stability of nanocomposite PEM. The Nafion/SNMMT composite PEM achieves 0.275 S cm−1 proton conductivity at 95 °C in water, evidently beyond any previously reported composite PEMs using normal SMMT. Equipped with this reformed nanocomposite PEM, both PEMFC and DMFC display competitive peak power densities (1.121 W cm−2 with H2/O2 at 80 °C/100 % relative humidity (RH) for PEMFC, and 0.228 W cm−2 with 1.6 M methanol/100 % RH O2 for DMFC), and simultaneously show minor performance deteriorations in constant current density operation and RH cycle tests. It would be instructive the specific focus and reformation on the uniformity and sufficiency of filler modification may render significant interface and performance advancements for nanocomposites.

Factors Influencing the Decision-Making Process at the End-of-Life Cycle of Onshore Wind Farms: A Systematic Review

It is observed that the number of onshore wind farms that reach the end of their service life is continually increasing. The decision-making process that defines the future of the farm is a challenge for the owners. This systematic review aimed to identify which factors influence the decision-making process at the end-of-life cycle of onshore wind farms. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol, a research strategy was developed and used the Scopus, Web of Science and EMBASE databases. Initially, 2767 articles were identified, but, after double-blind screening, 26 articles were analyzed in full. The scarcity of studies on this topic and little elucidation are limitations of this review. The results include (i) a systematization of six options for decision making, (ii) thirteen factors influencing the decision-making process associated with categories of external factors (logistics and infrastructure aspects, regulatory aspects and public policies, national energy guidelines, the technological development of the sector); and internal factors (economic/financial, operational and environmental aspects). It is concluded that most of the publications consist of simulations and theoretical studies highlighting a bottleneck in experiences and feasible data to support decisions at the end of service life. It is highlighted that most of the studies showed that partial decommissioning with partial repowering, as well as total decommissioning, were the most feasible options for the end-of-life cycle, with aspects related to public policies and regulatory aspects, as well as environmental, operational and economic/financial aspects, being the most influential, especially due to the wake effect, operation and maintenance costs (OPEX) and the protection of guarantees and incentives for operation in a new operating cycle.