Industrial Fields Research Articles

Algal biomass-based zero-waste biorefinery for producing optically pure (R)-γ-valerolactone and carbonaceous electrodes applicable for energy storage devices

Mankind is facing a severe climate crisis caused by fossil fuel-derived CO2 emissions. Although biorefineries utilizing biomass have been considered the best option for carbon-neutrality, most biorefinery-derived products have not yet been promising for economic feasibility; various strategies have been developed to increase economic competitiveness, and zero-waste biorefineries are challenging options. Herein, we aim to develop an algal biomass-based zero-waste biorefinery for producing enantioselective (R)-γ-valerolactone ((R)-GVL) and carbonaceous electrodes applicable for Li-ion batteries (LiBs). Various algal biomasses were hydrothermally oxidized to produce levulinic acid (LA) as an intermediate for producing (R)-GVL, resulting that Gracilaria verrucosa was selected as feedstock. For the hydroxylation of G. verrucosa-derived LA to 4-hydroxyvaleric acid (4-HV), 3-hydroxybutyrate dehydrogenase (HBDH) was explored through genome mining and further engineered. The engineered HBDH successfully converted G. verrucosa-derived LA to 4-HV, which was subsequently lactonized under acidic conditions, resulting in optically pure (R)-GVL. To our knowledge, this is the first report of the production of an algal biomass-derived enantioselective (R)-GVL with a perfect enantiomeric excess (>99.99 %) that can be used as a precursor for more valuable biopharmaceuticals and bioplastics than biofuels. Furthermore, residual G. verrucosa after hydrothermal oxidation was used as a carbonaceous anode material for LIBs for the first time; hard carbon anodes, which were prepared through simple heat treatment (800 ℃, 3 h, argon atmosphere), exhibit good capacities of 231, 191, 133, 108, 97 and 86 mAh/g at 0.05, 0.1, 0.5, 1, 1.5, and 2 A/g, respectively. The results discussed herein can provide insights into zero-waste biorefineries applicable for diverse industrial fields (e.g., biopolymer, biopharmaceutical and energy storage) and contribute to the construction of closed-carbon-loops for coping with climate change.

СУЧАСНИЙ СТАН, ОСОБЛИВОСТІ ТА ПЕРСПЕКТИВИ СПІВРОБІТНИЦТВА УКРАЇНИ З КРАЇНАМИ-УЧАСНИЦЯМИ АСЕАН

The purpose of the article is to analyze the main areas of foreign economic cooperation of Ukraine with ASEAN member countries and to determine the future prospects of their interaction. The article examines the trade and economic relations of Ukraine with ASEAN member countries during 2014-2022. An analysis of the volume of trade in goods between the parties is presented, which indicates a gradual increase in trade turnover from 2015 to 2021 and its further reduction in 2022 due to the start of a full-scale war The main categories of export and import of goods between Ukraine and ASEAN member countries in 2022 have been determined, which include grain crops, vegetable fats and oils, telecommunications equipment, metal products, etc. The geographical structure of trade operations was analyzed and the most popular export and import destinations for Ukraine, such as Malaysia and Vietnam, were determined. It is proven that, despite the gradual increase in trade volumes, the level of investment activity between the parties remains low, which is determined by a number of negative factors, including the war with Russia, corruption and the uncertainty of the legal environment in Ukraine. Positive factors that increase the investment attractiveness of Ukraine for the countries of Southeast Asia are considered, in particular, the geopolitical position and the presence of a highly qualified workforce. Based on the data of the National Bank of Ukraine, it was determined that the largest number of investments in Ukraine comes from Singapore, in particular, in enterprises in the fields of industry, trade and agriculture. The existence of significant potential for the development of trade and economic relations between Ukraine and ASEAN member countries has been proven. Ways of intensifying bilateral cooperation were proposed, such as the implementation of joint projects in the field of information technology and infrastructure, increasing the volume of Ukrainian exports and the creation of special economic zones. The need to sign trade agreements and expand business ties for the further development of cooperation between Ukraine and ASEAN member countries is highlighted.

Recent progress in piezoelectric thin films as self-powered devices: material and application

Piezoelectric materials have become a key component in sensors and actuators in many industrial fields, such as energy harvesting devices, self-powered structures, biomedical devices, nondestructive testing, owing to the novel properties including high piezoelectric coefficient and electromechanical coupling factors. Piezoelectric thin films integrated on silicon substrates are widely investigated for their high performance and low manufacturing costs to meet the requirement of sensor networks in internet of things (IoT). The aim of this work is to clarify the application and design structure of various piezoelectric thin films types, synthesis methods, and device processes. Based on latest literature, the process of fabricating thin film sensors is outlined, followed by a concise overview of techniques used in microelectromechanical systems (MEMS) processing that can integrate more complex functions to obtain relevant information in surrounding environment. Additionally, by addressing piezoelectric thin films sensors as a cutting-edge technology with the ability to produce self-powered electronic devices, this work delivers incisive conclusions on all aspects of piezoelectric sensor related features. A greater understanding of piezoelectricity is necessary regarding the future development and industry challenges.

Anti-Coronavirus Potential of Polyether Ionophores: The New Application of Veterinary Antibiotics in Livestock.

Coronaviruses have consistently posed a major global concern in the field of livestock industry and public health. However, there is currently a lack of efficient drugs with broad-spectrum antiviral activity to address the challenges presented by emerging mutated strains or drug resistance. Additionally, the method for identifying multitarget drugs is also insufficient. Aminopeptidase N (APN) and 3C-like proteinase (3CLpro) represent promising targets for host-directed and virus-directed strategies, respectively, in the development of effective drugs against various coronaviruses. In this study, maduramycin ammonium demonstrated a broad-spectrum antiviral effect by targeting both of the proteins. The binding domains 4 Å from the ligand of both target proteins shared a structural similarity, suggesting that screening and designing drugs based on these domains might exhibit broad-spectrum and highly effective antiviral activity. Furthermore, it was identified that the polyether ionophores' ability to carry zinc ion might be one of the reasons why they were able to target APN and exhibit antiviral effect. The findings of this experiment provide novel perspectives for future drug screening and design, while also offering valuable references for the utilization of polyether ionophores in the management of livestock health.

Ultrafast dyeing wastewater purification by high-performance and reusable lignin-derived activated porous carbon filter

Achieving ultrafast purification during filtration while maintaining high adsorption capacity and low-cost filter production is a critical challenge that must be addressed immediately to promote large-scale water filter applications, particularly in remote areas without wastewater purification plants. Herein, low-cost, renewable lignin was used as a carbon source precursor to produce a high-performance, reusable activated porous carbon filter for ultrafast dye wastewater purification. Lignin-derived active porous carbon (LAPC) can achieve a high specific surface area (2276 m2/g) by using a lower amount of KOH (a mass ratio of 0.4 KOH to precursor) during the activation process, which not only meets the requirements of water transport and dye adsorption, but also reduces manufacturing costs. Owing to the pore-filling effect and electrostatic interaction, the LAPC particles displayed a high removal capacity of 1800 mg/g in the static adsorption, higher than most of the reported porous carbon. Furthermore, LAPC filters assembled from a flow of LAPC particles achieve significant dye removal (99.82 % in 30 s) during the dynamic adsorption process. Both anionic and cationic dyes can be removed and clean water can be produced simultaneously by simple dynamic filtration. Moreover, the LAPC filter could be reused for wastewater purification with a high removal efficiency (more than 95 % after 7 cycles of regeneration and use). This continuous operation, strong absorption versatility, and high efficiency of LAPC filter device for complex hybrid dyes system make it have a bright prospect in industrial dyeing wastewater treatment fields.

Optimized sulfur curing of pulse-damping rubber tubes

In pumping systems present in the industrial field, positive displacement pumps are used due to the high manometric loads and the characteristics of the extracted fluid. However, this type of pump provides a pulsating flow in the system that causes large pressure fluctuations, reducing the useful life of the installations. Because of this problem, pulsation dampers (attenuators) are used in the system in order to promote a more continuous flow and the good functioning of the process. In-line type attenuators feature a flexible tube composed of elastomer, whose viscoelastic behavior causes flow attenuation. The objective of this work is to evaluate whether there is a relationship between the sulfur content present in blends of natural rubber (NR) and synthetic rubber of the Butadiene Styrene (SBR) and the performance of tubular attenuators in a pumping system with pulsating flow. Four NR/SBR rubber blends with different sulfur concentrations in the formulation (0.5; 1.5, 3.0 and 4.5 phr) were tested. The rubbers were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and their mechanical properties were analyzed using mechanical tensile tests. The efficiency of the attenuators was evaluated through bench tests that simulate pumping systems in the field. The results of the mechanical tests showed significant relationships with the performance of the attenuators in experimental tests. In attenuation tests, blends with 1.5; 3.0 and 4.5 phr sulfur had attenuation results of 27.06 %, 9.70 % and 1.61 %, respectively. The 0.5 phr attenuator could not withstand the applied loads due to lack of elastic properties. Thus, it was found that materials with a lower modulus of elasticity had greater efficiency in attenuating the pulsating flow and greater compliance, in which the attenuator that was formulated with 1.5 phr of sulfur showed 25.45 % greater pulsation damping than the stiffer material.

DAT: A robust Discriminant Analysis-based Test of unimodality for unknown input distributions

This letter introduces a Discriminant Analysis-based unimodality Test (DAT) for automatically identifying whether a dataset is unimodal or multimodal, detecting deviations in time series datasets, estimating statistical parameters, and identifying the skewness of the data. DAT is effective in classifying datasets under both unimodal and multimodal conditions and is suitable for bi-classification applications. The performance of DAT was compared to two well-known unimodality tests, namely the dip and folding tests, and is shown to perform better. We then extended DAT to the development of a fault detection technique, which was tested against five different machine learning classifiers using data from the Case Western Reserve University (CWRU) ball bearing database. The results obtained show that the proposed approach is effective, achieving 99.999% accuracy for detecting small ball bearing fault sizes (0.007 inches). Our conclusion indicates a significant potential of the proposed test for improving anomaly detection in industrial and other related fields.

Thermal hydraulic characteristic of thermosyphon pressurized with non-condensable gas

Thermosyphon or wickless heat pipe has been applied in many fields of industry due to its high thermal conductance and passive working principle. Many studies have been done to elucidate the complex thermal hydraulic phenomena inside thermosyphon. Parameters such as geometry, type of working fluid, inclination angle of operation, confinement and entrainment have been major focal points in discussion related to thermosyphon research. However, in recent experimental studies, it has been reported that adding non-condensable gas along with working fluid during the initial charging of thermosyphon increase its entrainment limitation. This finding is important, considering some previous studies regard the presence of non-condensable gas as a hinderance on thermosyphon's condenser performance. In this study, experiments were conducted on a pressurized thermosyphon charged with water and argon gas as a non-condensable substance. Observations have been made especially on the case where cooling temperature on the outside of the condenser is far below operation temperature inside thermosyphon. It was found that low thermal conductivity of non-condensable gas causes large temperature gradient along the condenser. For this condition, currently available correlations cannot be applied. Therefore, experiments were required to prove this hypothesis, involving varying amounts of non-condensable gas. These amounts were expressed by the initial pressure values, ranging from 13 kPa to 160 kPa. The analysis of heat transfer in the evaporator and the condenser was conducted using correlations available in the literature. It was found that a new model is required to describe thermal-hydraulic phenomena in the condenser. The model is currently being validated with experimental data and good agreement has been achieved.

Towards direct superlubricity and negligible wear with polyalcohol lubricant mixtures of ethylene glycol and glycerol for steel tribopairs

Friction and wear remain as the main concerns in the mechanical mobility systems due to the significant energy consumption and the main mode of component failures, and achieving direct superlubricity has attracted enormous attention by fundamentally minimizing friction and wear. In this work, we have prepared polyalcohol lubricant mixtures of ethylene glycol and glycerol to precisely enhance the in-situ formation of passivation film on the friction surfaces, and remarkable direct superlubricity of 0.0057 combined with negligible wear has been successfully achieved at ethylene glycol/glycerol weight ratio of 0.6 for steel tribopairs. Lubrication state analysis indicates that the achieved superlubricity state is in the boundary lubrication regime, and further adsorption analysis indicates that there is a strong interaction between lubricant molecules and friction surfaces via the hydroxyl groups. A sliding simulation of polyalcohol lubricant mixtures of ethylene glycol and glycerol indicates that ethylene glycol could be induced to accumulate near the friction surfaces to form easy-to-shear layers. Furthermore, both the experimental analysis and the molecular dynamics simulation demonstrate that a tribochemical reaction could be induced for the lubricant molecules at the interface, with water molecules formed to further strengthen the formation of easy-to-shear layers and oligomers formed to more effectively passivate the asperity contacts. This work provides a new strategy to direct liquid superlubricity and could advance the application of liquid superlubricity in the industry field.

Dynamic wire-pull rubber diaphragm for rapid formation and spatio-temporal investigation of multi-shape free-standing liquid films

Quantitative manufacturing and characterization of thin films are relevant in different scientific and industrial fields. Especially, for the studies of fluid dynamics, the experimental verification of theoretical models creates the need of a free-standing liquid film formation. Driven by the lack of fast and accurate liquid film forming technology, we present a novel device able to fabricate thin free-standing liquid films, which is based on a dynamic and adjustable diaphragm, the opening of which allows for the rapid formation of a self-supported liquid film confined in a wire-pull rubber band. The quantitative thickness mapping of the film formation and its time-resolved evolution are performed by digital holography in real-time. This builds up a strategy that allows for the accurate liquid film formation with controllable size and volume. As the results, multi-shape and multi-material thin films under controllable and stable conditions are successfully formed, including free-standing water, soapy water and glycerol films. A label-free spatio-temporal analysis method for flow dynamics is proposed: The full-field time series of film thickness is reassembled in a new coordinate system composed of radius, time, and thickness. Such spatio-temporal analysis reveals details of leveling and drainage processes. To the best of our knowledge, this is the first full-field quantitative thickness analysis of multi-shape and multi-material thin films. The proposed Dynamic Wire-pull Rubber Diaphragm (DWRD) together with the digital holography add-on offer characterization abilities with an unprecedented level of details allowing for a deeper understanding of the underlying thin film dynamics that can be useful in several different scientific and technological fields as biotechnology, life science, and nanotechnology.

Multistimulus‐Responsive Miniature Soft Actuator with Programmable Shape‐Morphing Design for Biomimetic and Biomedical Applications

AbstractMiniature soft actuators have garnered attention across healthcare, military, and industrial fields; however, soft actuators mostly have functions and applications in nature‐inspired biomimetic locomotion, without any specific approaches reported for biomedical applications. In biomedical applications, soft actuators must be biodegradable, biocompatible, and visible in vivo. This study presents a multifunctional soft actuator comprising chitosan and magnetic nanoparticles (MNPs) fabricated via facile casting and laser micromachining. The actuator demonstrates programmable shape morphing and responds swiftly to six stimuli: humidity, chemical solvents, near‐infrared (NIR) light, radio‐frequency (RF) heating, temperature, and magnetic fields. This actuator shows feasibility for biomimetic applications, such as flower, leaf, larva, and finger. Furthermore, the actuator demonstrates magnetic locomotion, real‐time X‐ray visibility, biocompatibility, and biodegradability both in vitro and in vivo. The multistimulus‐responsive shape‐morphing performance of the soft actuator has potential as a wireless miniature robot in various fields, including biomimetic and biomedical applications.

Availability of pesticide-treated seeds on the soil surface in different crops and countries: A comprehensive data set reflecting modern agronomic practice.

For plant protection products applied as seed treatments, the risk to birds and mammals possibly feeding on such treated seeds needs to be addressed in the EU, in order to register these products for commercial use. For this purpose, the European Food Safety Food Authority (EFSA) has provided guidance on how to execute such a risk assessment. The risk assessment follows a tiered approach. In the Tier 1 risk assessment of the EFSA guidance (2023), it is assumed that birds or mammals have ad libitum access to treated seeds and exclusively feed on treated seeds. Due to this conservative assumption, the Tier I risk assessment typically indicates an unacceptable risk to birds and mammals and higher-tier refinements are required. One option for refinement is to use data on the availability of treated seeds on the soil surface directly after drilling. Published data on seed counts are, however, limited to a few countries and crops, and often these data are not contemporary, that is, do not reflectadvances in sowing technology and current agronomic practice. To address this data gap, we provide recently generated data from industry field trials (the studies were conducted from 2000 to 2022, >70% between 2019 and 2022), covering 270 fields from seven countries (Austria, France, Germany, Hungary, Poland, Spain, UK) for spring and winter cereals, winter oilseed rape, and sunflower. This comprehensive data set realistically reflects modern agronomic practice and is thus suitable for consideration in a regulatory context for refining the risk assessment for birds and mammals. Integr Environ Assess Manag 2024;00:1-8. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Identification System for Short-Circuit Fault Points in Concentrated Stator Windings of Motors

Motors serve as the primary power sources in a wide range of industrial fields. In recent years, their application has been expanded to electric and hybrid electric vehicles. As the performance of the motors installed in electric vehicles directly affects human life, it is critical to diagnose the condition of the windings. The objective of this article is to establish a method to identify the short-circuit fault points in concentrated stator windings based on the magnetic flux density distribution near the stator windings. Unlike with distributed windings, the coils are wound around the teeth in concentrated windings. Thus, it is expected that the accurate position specification of the short circuit can be realized if a detailed magnetic flux density distribution over the teeth is obtained with an appropriate magnetic field sensor. The problem of sensor positioning is solved with two stepper motors moving the search coil in the rotational and longitudinal directions independently at specified intervals. The excellent capability of the proposed system is verified through experiments using the stator winding employed in hybrid electric vehicles. The accuracy and sensitivity of the proposed identification system for short-circuit fault points may enable its practical application in industries, for example, shipping and periodic inspections as well as the production management of motors with concentrated stator windings.

Preparation and photocatalytic and antibacterial properties of polyvinyl alcohol/chitosan/TiO2@Ag electrospun nanofibers

Polyvinyl alcohol (PVA) is a widely used polymer in the electrospinning technique. It is water-soluble, which limits the application of electrospun PVA matrix. In this study, chitosan (CS) and biosynthesized TiO2@Ag nanoparticles were incorporated into PVA to enhance its antibacterial properties and photocatalysis. The PVA/CS/TiO2@Ag nanofiber mat was prepared using the electrospinning method with a voltage of 20 kV, a needle-collector distance of 15 cm, and a flow rate of 0.5 mL.h−1. The concentrations of the PVA and CS solutions were 10% and 2%, respectively. The TiO2@Ag nanoparticles were synthesized using AgNO3 solution, TiO2 nanoparticles as precursors, and Cleistocalyx operculatus leaf extract as a reducing agent. The morphology and structure of the PVA/CS/TiO2@Ag nanofiber mat were analyzed using scanning electron microscopy and infrared spectroscopy. The PVA/CS/TiO2@Ag nanofibers exhibited an average fibril diameter of 116.4 nm. Additionally, the antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), as well as the photocatalytic properties of these mats, were assessed. The results indicated that the addition of CS and TiO2@Ag led to changes in the hydrophilic properties and antibacterial efficacy of PVA. The inhibition zones of the PVA/CS/TiO2@Ag nanofiber mat against E. coli and S. aureus were measured at 5 and 4 mm, respectively. The water contact angle of PVA/CS/TiO2@Ag nanofiber mat showed a significant increase. The PVA/CS/TiO2@Ag nanofibers were able to degrade 94.56 ± 0.57% and 98.17 ± 0.11% of methylene blue dye under sunlight irradiation after 10 and 20 min of exposure, respectively. These findings suggest that the PVA/CS/TiO2@Ag nanofiber mat has the potential for applications in the textile industry or medicinal field as antibacterial and photocatalytic coatings.

Evaluation of Industrial Field Practice Program using the Tyler Model in the Informatics Engineering Education Department

This research aims to describe the evaluation implementation of industrial field practices in the informatics engineering education study program, Faculty of Teacher Training and Education, Universitas Putra Indonesia "YPTK" Padang. This research used an evaluation method with the Tyler Evaluation Model (Goal Oriented Model). Based on this method, data was collected through the following steps: 1). Identify the objectives of industrial field practice; 2) formulate indicators for the achievement goals that have been set; 3) formulate the data obtained with indicators. The main objective is divided into sub-component objectives, namely: sub-component of program objectives, sub-component of attitudes, and sub-component of achieving program objectives. All indicators included in the sub-components were analyzed using the mixed method technique (quantitative and qualitative) and obtained an average score of 84.4 %. It means that the implementation of industrial field practice in the informatics engineering education study program, Faculty of Teacher Training and Education, Universitas Putra Indonesia "YPTK" Padang, is in a good category. The impact of the implementation of industrial field practices can run smoothly in accordance with the program objectives.

On-machine measurement and compensation of thin-walled surface

On-machine measurement technology is considered as a key technology for realizing closed-loop feedback control in intelligent manufacturing due to the reduction of the transfer process. However, the complexity of the machine tool process system introduces some uncertainty into the accuracy of on-machine measurement, which severely limits the application in the actual industrial field. To overcome the shortcomings of the existing uncertainty, an inspection framework for on-machine measurement of thin-walled surface is proposed. Firstly, a low-cost wireless on-machine measurement system based on potential signals is established and integrated into a manufacturing process line for automatic sampling. Then, the similarity of momentum conservation is introduced into sampling planning, and an adaptive sampling model based on momentum conservation and multi-objective particle swarm optimizer is proposed. Finally, a stacked deep learning model under the vertical inspection direction is proposed to improve the inspection accuracy by correcting the sampling data. Compared with existing sampling methods, the proposed model is similar to an attention mechanism that enables adaptive enhancement of profile features. The inspection performance by data correction is improved by about 16.14% in the mean inspection error. Simulations and experiments show that the proposed method has great advantages in terms of efficiency and robustness, which can provide a theoretical reference for adaptive toolpath correction for thin-walled surfaces.

An experimental study on the effect of CO2 laser powers on melting characteristics of clear ice − part I: Horizontal irradiation

Icing phenomenon widely exists in traffic and industrial fields, and causes a lot of safety accidents. Laser deicing technology is a typical high-efficiency and non-contact deicing method. To accurately predict and control the laser-induced ice melting process, an experimental study on melting characteristics of clear ice under horizontal CO2 laser irradiation and natural convection is carried out, with the laser power varied at a range of 20 ∼ 60 W. As resulted, in the first 27 s of the melting process, the axial melting rate is around 1.2 mm/s at each power. After 27 s, the laser power effect on the melting rate is obviously different, and the maximum melting rate reaches 5.41 mm/s at 50 W. The higher the laser power, the more the ice melts, and the easier the path of melting ice deflects. At 20 W and 50 W, the maximum angles of melting height are 1.14° and 4.18°, respectively. The laser power effect on the maximum melting height is obvious. At 20 W and 50 W, the peaks of maximum melting height are 12.84 mm and 22.59 mm, respectively. The higher the laser power, the larger the volume melting rate of ice, but the greater the energy loss, and it directly influences the energy efficiency. The ice-melting energy efficiency decreases with the increase of laser power. For laser at 20 W and 60 W, the maximum energy efficiency are 81.5 % and 54.6 %, respectively. This study is meaningful for the optimization of laser deicing technology.

Interpolation problems for random fields on Sierpinski’s carpet

The prediction of stochastic processes and the estimation of random fields of different natures is becoming an increasingly common field of research among scientists of various specialties. However, an analysis of papers across different estimating problems shows that a dynamic approach over an iterative and recursive interpolation of random fields on fractal is still an open area of investigation. There are many papers related to the interpolation problems of stationary sequences, estimation of random fields, even on the perforated planes, but all of this still provides a place for an investigation of a more complicated structure like a fractal, which might be more beneficial in appliances of certain industry fields. For example, there has been a development of mobile phone and WiFi fractal antennas based on a first few iterations of the Sierpinski carpet. In this paper, we introduce an estimation for random fields on the Sierpinski carpet, based on the usage of the known spectral density, and calculation of the spectral characteristic that allows an estimation of the optimal linear functional of the omitted points in the field. We give coverage of an idea of stationary sequence estimating that is necessary to provide a basic understanding of the approach of the interpolation of one or a set of omitted values. After that, the expansion to random fields allows us to deduce a dynamic approach on the iteration steps of the Sierpinski carpet. We describe the numerical results of the initial iteration steps and demonstrate a recurring pattern in both the matrix of Fourier series coefficients of the spectral density and the result of the optimal linear functional estimation. So that it provides a dependency between formulas of the different initial sizes of the field as well as a possible generalizing of the solution for N-steps in the Sierpinski carpet. We expect that further evaluation of the mean squared error of this estimation can be used to identify the possible iteration step when further estimation becomes irrelevant, hence allowing us to reduce the cost of calculations and make the process viable.

A novel hydroxyl‐rich polyvinyl alcohol hot‐melt adhesive with excellent ultra‐low temperature adhesion and reusability

AbstractEthylene‐vinyl acetate (EVA) hot‐melt adhesives featured good thermal stability, strong weather resistance and fast bonding speed, are of great concern to the industry and engineering fields. However, the weak bond strength and poor reusability severely hinder their application under harsh conditions. Herein, the hydrolyzed EVA (EVOH) copolymers with rich hydroxyl groups are fabricated by an EVA hydrolysis reaction, and their mechanical properties, environmental adaptability, and reusability were systematically evaluated. As a result, the shear strengths measured by bonding the stainless steel plates can reach up to 16.4 MPa at room temperature (25°C) and 13.1 MPa at ultra‐low temperature (−196°C), indicating the good bonding performance of EVOH. Besides, owing to the excellent dynamic reversibility and thermal stability, it can obtain 92% of shear strength retention rate after 10 reuses, which is the highest value reported so far. In addition, the hydroxyl‐rich EVOH delivers good solvent and corrosion resistance that can be widely used for bonding various materials. Therefore, this research provide new lightspots for developing environmentally friendly hot‐melt adhesives with excellent bonding properties, corrosion resistance, and reusability.

Doped rare earth elements enhance gas sensing properties of hollow spiral-like Mn(OH)F semiconductor sensors for acetate esters detection

This study successfully synthesized a series of Mn(OH)F hollow structures doped with rare earth elements (Sm, Nd, Ce, and Tb) using a hydrothermal method. A comprehensive analysis was conducted on the influence of these dopant elements on the morphology and gas-sensitive properties of Mn(OH)F. The gas-sensing performance of Mn(OH)F nanomaterials doped with Sm, Nd, Ce, and Tb was extensively investigated at 150℃ for methyl acetate, ethyl acetate, propyl acetate, and butyl acetate. The results demonstrated good gas-sensing capabilities, with responses reaching 2.0, 2.0, 2.0, and 2.5, respectively. Compared to undoped Mn(OH)F nanomaterials, the operating temperature of these sensors was reduced by about 100℃, and the response values were nearly tripled. Exceptional selectivity and stability were also observed. In addition, an in-depth exploration was conducted into the underlying mechanisms behind the enhanced gas response due to rare earth element doping. This study provides strong theoretical support for the development of efficient acetate ester gas sensors, demonstrating broad prospects for their widespread application in the industrial field.