A multi-criteria decision framework for selecting preventive maintenance measures on asphalt pavement: a case study of the Liuzhou North Ring Expressway

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A multi-criteria decision framework for selecting preventive maintenance measures on asphalt pavement: a case study of the Liuzhou North Ring Expressway.

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Credit: Zhen Wu, Mohd Rosli Mohd Hasan∗, Oumar Orozi Sougui /Universiti Sains Malaysia, Malaysia, Diyar Khan/Silesian University of Technology, Poland, Hainian Wang/Chang’an University, China，Hui Wang/Chongqing University, China

Using the Liuzhou North Ring Expressway in Guangxi as a case study, researchers developed a multi-level decision-making model comprising the comprehensive objective layer, criterion layer, indicator layer, and scheme layer. By combining road condition assessment with weighted evaluation factors, the optimal maintenance plan was determined. This achievement, published in the journal SC, shows that ultra-thin cover and composite seal coat technologies are highly reasonable in ranking and weight allocation, highly aligned with actual engineering needs, and provide solutions for maintenance decisions by management departments.

As expressway networks across China continue to age and expand, with limited budgets and diverse maintenance options, choosing the most effective preventive maintenance measures for thousands of kilometers of asphalt pavement is no longer just a technical issue; it is a costly and complex management challenge. To address these prominent issues, the research team has developed a multi-level decision-making framework for preventive asphalt pavement maintenance, successfully transforming the complex decision-making process into quantifiable evaluation models. The research results were recently published in the journal SC, providing scientific, transparent, and practical solutions.

Through a practical case study of the Liuzhou North Ring Expressway in Guangxi, the research team proposed a decision framework based on the Analytic Hierarchy Process Method (AHP). This framework addresses how to select maintenance measures. By establishing a four-level evaluation system that includes the objective layer, criterion layer, indicator layer, and scheme layer, it summarizes the core demands of highway maintenance into three dimensions. Researchers consider quality and construction difficulty, and incorporate economic cost, expected pavement service life, and environmental protection into the evaluation system. The system includes three dimensions: technology, economy, and environment, with indicators covering the construction quality, material quality, project cost, service life, traffic disruption, and aesthetic effects.

By analyzing measured data from the Liuzhou North Ring Expressway, the model prioritized five mainstream maintenance technologies. The ultra-thin cover and composite seal coat ranked among the top in comprehensive scores. In the current context of budget constraints and increasing environmental requirements, these two technologies strike the best balance between improving pavement performance, extending service life, and reducing environmental impact. Sensitivity analysis, simulating decision outcomes under different weightings, confirmed the model's robustness. Whether management focuses on technological enhancement or cost control, this framework provides consistent recommendations for decision-making.

By scientifically weighing various indicators, the study draws key conclusions: cost is the core factor, but not the only one. Among the factors influencing decision-making, unit cost remains the most direct influence, while environmental protection indicators and service life should not be overlooked. Using quantitative scoring, the study prioritized various curing techniques. In practice, ultra-thin cover and composite seal coat were rated as the preferred preventive maintenance solutions due to their balance between technical performance and economic benefits.

The biggest highlight of this study is its practicality. It is not just an academic theory, but a practical management tool that helps management departments conduct scientific evaluations and invest in the most cost-effective maintenance technologies. Through timely, scientific preventive interventions, the ageing of roads can be delayed. A clear scoring system is provided, ensuring that every decision in the maintenance project is traceable and reduces subjective arbitrariness in the decision-making process.

The research results show that this decision-making framework can be adjusted according to traffic flow, climate conditions, and management models in different regions, offering strong regional applicability. With the popularization of smart transportation technologies, this system will help China's expressway maintenance and management develop toward more refined and intelligent directions. Currently, the model has completed preliminary validation in real-world engineering settings, demonstrating close alignment with maintenance needs. In the future, the team plans to expand the pilot scope and introduce more intelligent evaluation methods, such as fuzzy mathematics and machine learning, to meet more complex road network maintenance needs. This marks a shift in the operation and maintenance of China's expressways from post-incident firefighting repairs to precise prevention, supporting the development of an efficient, green, and safe expressway network.

This Paper “A multi-criteria decision framework for selecting preventive maintenance measures on asphalt pavement: a case study of the Liuzhou North Ring Expressway” was published in the journal Smart Construction.

Citation: Wu Z, Mohd Hasan MR, Sougui OO, Khan D, Wang H, et al. A multi-criteria decision framework for selecting preventive maintenance measures on asphalt pavement: a case study of the Liuzhou North Ring Expressway. Smart Constr. 2026(2):0011, https://doi.org/10.55092/sc20260011.

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Journal

Smart Construction

DOI

10.55092/sc20260011 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

A multi-criteria decision framework for selecting preventive maintenance measures on asphalt pavement: a case study of the Liuzhou North Ring Expressway

 

Sunlight-powered chemistry reduces hazardous oxidant risk

Green process generates a reactive oxidant only as needed, reducing hazardous inventory while producing precision reagents for pharmaceutical synthesis

The University of Osaka

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Light-driven, green and safe access to Davis reagents

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Credit: The University of Osaka

Osaka, Japan — In chemical manufacturing, one of the most difficult safety challenges is not just making useful molecules, but managing dangerous reagents on the way. This is especially true for the synthesis of Davis reagents, important tools for building pharmaceutical molecules, which has traditionally relied on bulk amounts of meta-chloroperbenzoic acid (mCPBA), a powerful oxidant that can pose serious explosion risks during transport, storage, and scale-up. Researchers at the University of Osaka have now found a way around that problem, instead of storing the oxidant, they make it only when needed, using light and oxygen.

A research team led by Professor Shinobu Takizawa at SANKEN developed a safe and sustainable sequential process for preparing Davis reagents. Instead of handling bulk meta-chloroperbenzoic acid (mCPBA), a powerful but potentially explosive oxidant, the method produces mCPBA in situ from meta-chlorobenzaldehyde and molecular oxygen under sunlight or LED irradiation, and immediately uses it to oxidize N-sulfonyl imines.

The key advance is that the oxidant is generated only as needed. Kinetic analysis showed that mCPBA forms in the reaction mixture but does not accumulate to detectable levels, because it is consumed essentially as soon as it is produced. This greatly reduces the risks associated with storing or handling bulk peracids.

The method also aligns with green chemistry principles. The reaction proceeds at ambient temperature, avoids halogenated solvents, and can be driven by natural sunlight or low-energy LEDs. The researchers also demonstrated broad substrate scope and gram-scale synthesis, obtaining the target product in 76% isolated yield under sunlight.

Professor Takizawa commented, “Developing technologies that manufacture essential compounds for fine organic synthesis in safer and more environmentally friendly ways is an important challenge for realizing a sustainable society. This work proposes a new organic synthesis process that combines safety with environmental compatibility.”

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The article, “Kinetically guided on-demand mCPBA generation enables safe and sustainable light-driven synthesis of Davis reagents,” was published in Green Chemistry at DOI: https://doi.org/10.1039/d6gc02210c

 

About The University of Osaka

The University of Osaka was founded in 1931 as one of the seven imperial universities of Japan and is now one of Japan's leading comprehensive universities with a broad disciplinary spectrum. This strength is coupled with a singular drive for innovation that extends throughout the scientific process, from fundamental research to the creation of applied technology with positive economic impacts. Its commitment to innovation has been recognized in Japan and around the world. Now, The University of Osaka is leveraging its role as a Designated National University Corporation selected by the Ministry of Education, Culture, Sports, Science and Technology to contribute to innovation for human welfare, sustainable development of society, and social transformation.

Website: https://resou.osaka-u.ac.jp/en

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Journal

Green Chemistry

DOI

10.1039/d6gc02210c 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Kinetically guided on-demand mCPBA generation enables safe and sustainable light-driven synthesis of Davis reagents

 

Caption

On-demand generation of mCPBA from an aldehyde under light irradiation and its immediate use in imine oxidation to produce the Davis reagent, avoiding the accumulation of hazardous peroxide.

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The University of Osaka

 

Beyond heat: New infrared filter for thermal cameras could detect pollution and disease

ARC Centre of Excellence for Transformative Meta-Optical Systems

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The Researchers field tested the infrared sensors in drones

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Credit: Oleg Bannik

Australian researchers have developed a tiny, electrically tunable infrared filter that could help shrink bulky thermal sensing systems onto portable chips – potentially opening the door to handheld pollution detectors, compact multispectral cameras and next-generation chemical sensing devices.

The technology, developed by the Australian Research Council Centre of Excellence for Transformative Meta-Optical Systems researchers  at the TMOS nodes at The University of Western Australia (UWA) and The Australian National University (ANU), works in the long-wave infrared region – the part of the spectrum associated with thermal radiation emitted by objects that are near room temperature.

Their results were published in Advanced Materials Technologies.

While conventional thermal cameras mainly measure heat intensity, the new device was designed to help infrared systems distinguish between different materials and gases based on their spectral ‘fingerprints’.

Lead author, TMOS PhD Student Oleg Bannik, at the UWA node, says one useful way to think of the technology “is as ‘colour vision’ for thermal imaging.”

“Instead of seeing only hot and cold, a camera could compare several carefully selected infrared bands, similar to how the human eye combines red, green and blue wavelengths to perceive colour,” Bannik says.

“That could allow systems to tell the difference between gases, chemicals or materials that look identical in ordinary thermal images.”

For decades, infrared spectroscopy was restricted to labs, military systems and expensive industrial equipment. These were machines with mirrors, lenses and moving parts – but were often too bulky and power-hungry to leave controlled environments.

The device itself is a microscopic ‘sandwich’ of suspended gold and silicon membranes perforated with nanoscale holes.

By electrically changing the tiny gap between the layers – across distances smaller than a micron – the researchers could continuously tune which infrared wavelengths passed through the structure.

The work relies on a phenomenon known as ‘extraordinary optical transmission,’ where light passes through tiny holes in metallic films far more efficiently than expected.

In the team’s device, nanoscale movements strongly alter the infrared response of the system.

“The most counterintuitive part is that changing a gap by only a few hundred nanometres can strongly tune infrared light with wavelengths around ten microns,” Bannik says.

“Tiny nanoscale motions end up controlling much larger infrared waves through near-field plasmonic interactions.”

In laboratory testing, the researchers tuned the transmission peak from around 8 micrometres to 9.8 micrometres in wavelength using voltages below 10 volts. Simulations suggest the tuning range could eventually extend beyond the long-wave infrared region.

Unlike many existing infrared filtering systems, which rely on comparatively large moving optical components, the new approach operates using extremely small membrane motions and low power consumption.

“It is important to understand that, by itself, the device is only a tunable spectral filter, not a complete sensing system,” Bannik says.

“However, when combined with a thermal detector, it can add entirely new capabilities to infrared cameras and sensing platforms.”

He says environmental monitoring is one of the strongest potential applications, particularly for detecting methane leaks and industrial emissions.

“The technology could also benefit industrial safety, thermal imaging, medical diagnostics and defence systems where identifying materials matters more than simply measuring temperature,” Bannik says.

The paper points to the possibility of medical application, with spectrally selective thermal imaging systems capable of detecting subtle physiological changes invisible to conventional thermal cameras.

“The most realistic applications are non-contact diagnostics and advanced thermal imaging,” Bannik says.

“Different tissues emit infrared radiation differently, so spectrally selective thermal imaging could potentially help identify inflammation, monitor wounds or detect subtle physiological changes invisible to standard thermal cameras.”

These lightweight, low-power infrared sensors could also be especially useful in drones and portable field systems.

“Drones are probably the most realistic near-term platform because they benefit enormously from lightweight, low-power sensors,” he says.

Still, significant engineering challenges remain before the technology leaves the lab, particularly around manufacturing reliability and contamination control at extremely small scales.

“One of the hardest engineering challenges was maintaining extremely flat suspended membranes separated by gaps smaller than a micron,” Bannik says.

“At these scales, even dust particles only a few hundred nanometres wide can block membrane motion or distort the optical response.”

“The physics works well, but turning delicate laboratory devices into robust commercial products is a major engineering challenge.”

He says the work points to a future where bulky infrared spectrometers could eventually be replaced by compact, chip-scale systems.

“What makes this work exciting is the combination of advanced physics with a very practical goal,” Bannik says.

“The idea that nanometre-scale motion can give machines a richer understanding of the thermal and chemical world is both scientifically fascinating and potentially very useful in real-world sensing systems.”

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Journal

Advanced Materials Technologies

DOI

10.1002/admt.202502605 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Tunable Extraordinary Optical Transmission in the Long-Wavelength Infrared Range Using Electrostatic MEMS Actuation

 

Electric propulsion is not always the answer for small vessels

Estonian Research Council

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Diagram explaining that the best decarbonization option for a small ship depends on emissions performance, operational conditions, cost, and port infrastructure, rather than on technology alone. Author: Riina Otsason

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Credit: Riina Otsason

As shipping faces growing pressure to cut greenhouse gas emissions, new doctoral research from Tallinn University of Technology shows that the cleanest solution for small vessels is not one-size-fits-all. Instead, the best decarbonization pathway depends on route length, electricity supply, port infrastructure, vessel duty cycle, and investment costs. The thesis focuses on vessels below 5,000 gross tonnage (GT), a segment that includes ferries, pilot boats, and regional service vessels that have received far less attention than large ocean-going vessels.

Riina Otsason’s doctoral thesis, Environmental and Techno-Economic Assessment of Decarbonization Pathways for Ships Below 5,000 GT, combines life-cycle assessment, techno-economic modelling, and scenario analysis across four case studies in Estonia and beyond. The studies compare electric and diesel ferries, alternative fuels for pilot vessels, fleet-level decarbonization scenarios for regional ferry lines, and a ground-effect vehicle concept for inter-island transport. Together, they show how environmental performance, economic feasibility, and operational constraints interact in small-vessel decarbonization.

The findings suggest that meaningful emission reductions are technically possible, but the best option depends strongly on context. In one case study, a battery-electric ferry produced about 75% lower greenhouse gas emissions than its diesel sister vessel under the prevailing electricity mix. In another, biomethane delivered the highest emissions reduction potential for a pilot fleet, at roughly 59% compared with marine diesel oil. Across the full thesis, electrification performed best on short, predictable routes with low-carbon electricity and adequate charging infrastructure, while bio-based fuels and hybrid systems offered more practical transitional solutions in more variable operating environments.

The research also shows that technical feasibility does not automatically translate into financial viability. Battery-electric propulsion can reduce operating costs over time, but it typically requires higher upfront capital expenditure than diesel alternatives. In the ferry case study, the estimated payback period was about 17 years without subsidies, improving to around 10 years when financial support mechanisms were included. For small fleets operating with narrow margins, that makes investment risk a decisive factor.

According to the thesis, infrastructure readiness is just as important as vessel technology. Small vessels are especially sensitive to trade-offs between energy density, storage capacity, weight, range, safety requirements, and port infrastructure. Route length, charging availability, fuel supply chains, and grid capacity all shape what can realistically be deployed. The conclusion is clear: decarbonizing smaller vessels is not simply a matter of replacing one engine with another, but of matching the right technology to the right route and the right supporting infrastructure.

The work is particularly relevant for regions with islands, ferries, and coastal services, where maritime transport is part of everyday mobility and local air quality. By focusing on a segment that has been comparatively underexamined in maritime climate research, the thesis offers evidence that could help ship operators, port planners, and policymakers identify practical transition pathways for short-sea and regional transport.

Otsason’s thesis was defended at the Estonian Maritime Academy, Tallinn University of Technology, on 11 June 2026. The work was supervised by Prof. Ulla Pirita Tapaninen, with opponents Magnus Gustafsson of Åbo Akademi University and Prof. Tae Eun Kim of UiT The Arctic University of Norway.

About the thesis

The dissertation integrates four peer-reviewed publications and evaluates alternative propulsion systems and fuel pathways in small-vessel contexts. It argues that small-vessel decarbonization is achievable, but only when environmental goals are aligned with vessel characteristics, route conditions, and infrastructure readiness.

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Method of Research

Computational simulation/modeling

 

TS Laevad ferries. Source: TS Laevad.

Credit

TS Laevad

 

A COF-graphene hybrid opens new horizons for lithium-sulfur batteries

A group of researchers from Tohoku University has solved a long-standing barrier to the mass adoption of lithium-sulfur batteries

Tohoku University

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Schematic depiction of a Li-S battery equipped with a TUS-44@G interfacial layer, where synergistic polysulfide confinement and redox catalysis regulate sulfur-species evolution, facilitate rapid conversion among S8, soluble lithium polysulfides, and Li₂S₂ / Li₂S, suppress shuttle migration, and sustain stable long-term electrochemical operation.

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Credit: Yuichi Negishi et al.

Lithium-sulfur (Li-S) batteries combine the abundance and affordability of sulfur with an energy-storage capability far beyond that of current lithium-ion technologies. Practical deployment, however, has been slowed by a long-standing challenge known as polysulfide shuttling, whereby dissolved sulfur intermediates migrate within the battery, leading to active-material loss and premature performance decay.

Now, researchers from Tohoku University and collaborating institutions have tackled this problem by developing a molecularly designed covalent organic framework (COF)-graphene interlayer. This lightweight interface mitigates polysulfide shuttling by combining chemical trapping, rapid charge transport, and sulfur-conversion promotion.

The work was published in the journal Small on June 16, 2026.

Li-S batteries generate electricity through a remarkable sequence of chemical transformations. During discharge, solid sulfur is converted into soluble lithium polysulfides and then into lithium sulfides. During charging, the process is reversed. This multielectron reaction network enables sulfur to store far more energy than the cathode materials used in today's lithium-ion batteries, making Li-S technology an attractive candidate for next-generation energy storage.

Yet the very chemistry that gives Li-S batteries their enormous energy-storage potential also creates their greatest weakness. The intermediate lithium polysulfides formed during cycling behave much like wandering travellers: once dissolved in the electrolyte, they can escape from the sulfur cathode, drift across the separator, and reach the lithium-metal anode. This uncontrolled migration initiates a cascade of detrimental processes, including parasitic side reactions, depletion of active sulfur, growth of unstable interfacial layers, self-discharge, and a steady erosion of battery capacity with repeated use.

Prevention, however, does not lie in erecting a physical barrier. Instead, the separator interface must function more like an intelligent checkpoint. It should be capable of selectively recognizing polysulfide species, capturing them through strong chemical interactions, rapidly shuttling electrons to sustain electrochemical activity, and actively guiding sulfur intermediates through their successive reduction and oxidation steps. Combining these diverse functions within a single material platform has remained one of the central challenges in advancing practical Li-S batteries.

To solve this issue, the team created a new tetrathiafulvalene-crown ether COF, named TUS-44, and integrated it with conductive graphene to form a TUS-44@G functional layer for Li-S batteries. The framework contained imine nitrogen, crown-ether oxygen, and sulfur-rich tetrathiafulvalene sites, which together provide a hierarchy of interaction sites for lithium polysulfides while the graphene component supplies an efficient electron-transport pathway.

In battery tests, cells equipped with the TUS-44@G layer delivered a high reversible capacity of 1455.7 mA h g⁻¹ at 0.2 A g⁻¹, retained excellent rate capability with 773 mA h g⁻¹ at 10 A g⁻¹, and showed long-term durability with only 0.034% capacity fading per cycle over 1000 cycles at 5 A g⁻¹. A Li-S pouch cell incorporating the same interlayer achieved an initial energy density of approximately 674 Wh kg⁻¹ at 0.05 A g⁻¹, demonstrating the promise of this molecularly engineered interface for practical high-energy batteries.

"Our goal was to design an interlayer that does not simply block polysulfides, but actively manages their reaction pathway," explains Saikat Das, Junior Associate Professor at the Institute of Multidisciplinary Research for Advanced Materials, Tohoku University. "By integrating crown ether and tetrathiafulvalene chemistry into an ordered COF and coupling it with graphene, we created a cooperative interface that can anchor, redistribute, and convert sulfur species more efficiently."

COFs offer an appealing solution because they can be constructed with molecular-level precision. Unlike conventional porous carbons, which interact only weakly with polysulfides, COFs possess periodically arranged pores whose dimensions, chemical environments, and electronic characteristics can be programmed by design. In essence, COFs provide a molecularly engineered platform that simultaneously captures, conducts, and catalyzes, offering a powerful strategy to transform the long-standing polysulfide shuttle problem from a major obstacle into a controllable aspect of sulfur electrochemistry.

The team synthesized TUS-44 through Schiff-base condensation between a benzo[18]crown-6 tetrabenzaldehyde linker and a tetrathiafulvalene-based tetraaniline building block. Structural analysis confirmed an imine-linked, π-conjugated, two-dimensional bex-topology framework with uniform micropores of approximately 0.9 and 1.2 nm and a BET surface area of about 516 m² g⁻¹.

The team also discovered that TUS-44 is not merely a porous scaffold but a molecularly programmed interface in which distinct functional sites perform complementary tasks. Imine nitrogen atoms serve as preferential docking sites for lithium ions, crown-ether oxygen atoms facilitate additional ion coordination and transport, while electron-rich tetrathiafulvalene moieties promote charge delocalization and mediate sulfur redox reactions. Integrating TUS-44 with graphene onto a polypropylene separator produced a thin, homogeneous interfacial coating that readily absorbs electrolyte and effectively blocks the migration of soluble polysulfides.

"This study shows that reticular chemistry can be used to program battery interfaces at the molecular level," remarks Professor Yuichi Negishi of Tohoku University. "The TUS-44@G design offers a route toward lightweight, durable, and high-rate Li-S batteries by unifying polysulfide immobilization with catalytic sulfur conversion."

 

Reticular assembly of the TUS-44 framework and crystallographic verification through powder X-ray diffraction studies.

Credit

Yuichi Negishi et al.

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Journal

Small

DOI

10.1002/smll.74240 

Article Title

Polysulfide Immobilization and Sulfur Conversion Kinetics Promotion via a Tetrathiafulvalene-Crown Ether COF@Graphene Layer for High-Rate Lithium-Sulfur Batteries