Conventional bioplastic production from seaweed often relies on extraction processes that are costly,time-consuming,and yield limited product.This study presents a direct fabrication method using Gracilaria sp.,a red ...Conventional bioplastic production from seaweed often relies on extraction processes that are costly,time-consuming,and yield limited product.This study presents a direct fabrication method using Gracilaria sp.,a red seaweed rich in polysaccharides,to produce bioplastic films without the need for extraction.Sorbitol was incorporated as a plasticizer at concentrations of 0%–10%(w/w)to modify film characteristics.Thermal analysis revealed improved stability at moderate sorbitol levels(5%–7%),while excessive plasticizer slightly reduced thermal resistance.Mechanical testing showed that sorbitol increased film flexibility and elongation at break,though tensile strength and stiffness declined.Tear strength followed a non-linear trend,with improvement observed at higher sorbitol concentrations.Seal strength also increased,peaking at 7%,indicating stronger interfacial bonding between film layers.Biodegradation tests demonstrated accelerated decomposition with increased sorbitol content,achieving complete degradation within 30 days at 10% concentration.Color analysis showed increased brightness and reduced yellowing,enhancing the visual quality of the films.These results confirm that direct conversion of bioplastic is both feasible and effective.Sorbitol plays a key role in tuning film properties,offering a low-cost,scalable pathway to biodegradable materials suitable for environmentally friendly packaging applications.展开更多
The chain dynamics heterogeneity of the poly(vinyl butyral)(PVB) plasticized by triethylene glycol bis(2-ethylhexa noate)(TEG-EH) was investigated by various solid-state NMR techniques.The plasticized PVB shows two do...The chain dynamics heterogeneity of the poly(vinyl butyral)(PVB) plasticized by triethylene glycol bis(2-ethylhexa noate)(TEG-EH) was investigated by various solid-state NMR techniques.The plasticized PVB shows two domains in distinct molecular dynamics differences,namely,rigid and soft domains,where the latter is the plasticizer-rich domain.The time domain low field NMR was first used to investigate the dynamics heterogeneity of the plasticized PVB,and the results show the decreasing activated energy of components in the soft domain of plasticized PVB(E_a=20.2 kJ/mol) as compared with that of the pristine one(E_a=24.3 kJ/mol).Detailed dynamics heterogeneity was obtained by high-field NMR with site-specific features.The quadrupole-echo ~2H-NMR was adopted to elucidate the dynamics heterogeneity of the vinyl alcohol(VA) units,where only the hydroxyl group of VA is deuterated.The ~1H-^(13)C WISE NMR spectra show that there is not much difference in the mobility of the VB unit in PVB with and without plasticizer,whereas the glass transition temperature differed by approximately 53℃.This is further supported by Torchia's T_1 relaxation measurements.The origin of such an unusual phenomenon is attributed to the critical role of the remaining VA(~22%) in the soft domain,where the VA units locally aggregate through hydrogen bonding.Also,the existence of a mobility gradient in the VB unit has been demonstrated.Moreover,the mobility difference for VB with different stereo-geometry(meso or racemic conformation) is observed for the first time.This indicates the importance of modulating the ratio of meso over racemic VB for controlling the macroscopic perfo rmance of PVB.展开更多
Commercial lithium-ion batteries(LIBs)use polyolefins as separators.This has led to increased research on separators composed of renewable materials such as cellulose and its derivatives.In this study,the ionic conduc...Commercial lithium-ion batteries(LIBs)use polyolefins as separators.This has led to increased research on separators composed of renewable materials such as cellulose and its derivatives.In this study,the ionic conductivity of cellulose acetate(CA)polymer electrolyte membranes was enhanced via plasticization with citric acid and succinonitrile.The primary objective of this study was to evaluate the effectiveness of these plasticizers in improving cellulose-based separator membranes in LIBs.CA membranes were fabricated using solution casting technique and then plasticized with various concentrations of plasticizers.The structural,thermal,and electrochemical properties of the resulting membranes were characterized using Fourier Transform infrared(FTIR)spectroscopy,X-Ray Diffraction(XRD),Differential Scanning Calorimetry(DSC),Thermogravimetric Analysis(TGA),and Electrochemical Impedance Spectroscopy(EIS).The FTIR and XRD results confirmed the successful incorporation of citric acid and succinonitrile into the polymer matrix,while the TGA analysis demonstrated the enhanced thermal stability of the plasticized membranes.The shift in the glass transition temperature was determined by DSC analysis.Most notably,the EIS results revealed a significant increase in ionic conductivity,achieving a maximum of 2.7×10^(-5) S/cm at room temperature.This improvement was attributed to the effect of plasticizers,which facilitated the dissociation of lithium salts and increase the mobility of the lithium ions.The ionic conductivities of plasticized CA membranes are better than those of unmodified CA membranes and commercially available Celgard separator membranes:4.7×10^(-6) and 2.1×10^(-7) S/cm,respectively.These findings suggest that citric acid and succinonitrile are effective plasticizers for cellulose acetate membranes,making them promising substitutes for commercial polyolefin separators in LIB applications.展开更多
Nitrate ester plasticized polyether(NEPE)is a kind of high-energy solid propellant that has both good mechanical properties and high specific impulse.However,its unique composition makes its combustion mechanism diffe...Nitrate ester plasticized polyether(NEPE)is a kind of high-energy solid propellant that has both good mechanical properties and high specific impulse.However,its unique composition makes its combustion mechanism different from both double-base propellants and composite propellants.In order to study the combustion mechanism of NEPE propellants,we improved the free radical cracking model of previous research to make it capable of predicting the burning rate of NEPE propellants.To study the combustion characteristics and provide data support for the model,an experimental system was built and four kinds of NEPE propellants with different compositions and grain size distributions were tested.The results show that our modified model can reflect the combustion characteristics of NEPE propellants with an acceptable accuracy.The difference between the model and the experimental data is mainly caused by uncertain environmental factors and the ignorance of interactions between components.Both the experimental data and the results predicted by the model show that increasing the backpressure helps to increase the burning rate of NEPE propellants.Furthermore,the grain size of the oxidizer inside the NEPE propellant has a more severe impact on the burning rate but a lighter impact on the burning rate pressure exponent in comparison with the grain size of aluminum.For aluminum-free NEPE propellants,the reaction in the gas phase is dominant in the combustion process while adding aluminum into the propellant makes the solid phase dominant in the final stage.The combustion of fine aluminum particles near the burning surface generates heat feedback to the burning surface which evidently influences the surface temperature.However,the agglomeration of coarse aluminum particles has little effect on the burning surface temperature.展开更多
The cation—conductive blends plasticized with propylene carbonate were prepared. The blends exhibited good mechanical strength and single—cation conduction over a wide range of plasticizer composition. The plasticiz...The cation—conductive blends plasticized with propylene carbonate were prepared. The blends exhibited good mechanical strength and single—cation conduction over a wide range of plasticizer composition. The plasticizer not only increases the conductivity of the blends but also decreases the electrochemical interface resistance between the blend and lithium electrode. The carrier in the blends obviously grows in number.展开更多
Novel microcellular foams using thin plasticized PC sheet were prepared by compression molding. The measurement results showed that T of plasticized PC was decreased and the molecular chain mobility was increased. Dec...Novel microcellular foams using thin plasticized PC sheet were prepared by compression molding. The measurement results showed that T of plasticized PC was decreased and the molecular chain mobility was increased. Decrease in T and increase in chains mobility were contributed to the widen of foaming temperature window. Effects of processing conditions on cell size, cell density and relative density were also investigated. The experimental results show that the temperature, tributyl citrate and foaming agent content have more effects on the structures and morphology of the plasticized PC microcellular foam. Effects of experimental conditions on cell size distribution have also been discussed.展开更多
The photodegradation of irradiated thin films of poly (para-methylstyrene) with 265 nm radiations in the presence of airand as a function of irradiation time has been studied using UV-VIS, fluorescence and FT-IR Spect...The photodegradation of irradiated thin films of poly (para-methylstyrene) with 265 nm radiations in the presence of airand as a function of irradiation time has been studied using UV-VIS, fluorescence and FT-IR Spectroscopic techniques. The influence of phthalate and terephthalate plasticizers on stability of poly (para-methylstyrene) towards irradiations was also investigated. Blending with phthalate plasticizers was found to cause a higher efficiency of photodegradation than that obtained in doping with terephthalate plasticizers. The intensity of absorption was also found to increase with time of irradiation and in change in the shape of the spectra at longer wavelength, thus indicating a possibility of photodegradation of polymer chains. The analysis of the FT-IR spectra of the irradiated and non-irradiated samples, shows a predominant absorption associated with carbonyl compounds with 1740 cm-1. In addition, the observed increase in the intensities of the carbonyl and hydroxyl regions of the FT-IR spectra, have provided an evidence for the photodegradation as well as photo-oxidation of polymeric chains. The presence of the plasticizer in the polymer backbone was found to accelerate the photodegradation of polymeric chains.展开更多
Blends of gelatin(Ge)plasticized with varying amounts of glycerol(Gly),buffer solution pH 10 and epoxidized soybean oil(ESO)to enhance hydrophobicity were prepared by mixing and injection-molding.Blends were character...Blends of gelatin(Ge)plasticized with varying amounts of glycerol(Gly),buffer solution pH 10 and epoxidized soybean oil(ESO)to enhance hydrophobicity were prepared by mixing and injection-molding.Blends were characterized by rheological tests and microscopy to select optimal conditions for scaling up their processing.The effect of each component on rheological response was analyzed using parallel plate geometry.Coating of gelatin specimens with PDMS during rheological tests led to reliable and reproducible results since water evaporation was prevented.A gradual increment in ESO concentration led to blends with increased degree of phase separation,as evidenced by optical and confocal microscopy.Limited compatibility between ESO and Ge increased viscosity at high ESO levels,but up to 10%Gly could be replaced with ESO without a significant variation of rheological behavior.展开更多
The effect of UV irradiation and blending with phthalate and terephthalate plasticizers on the photo-stability of Poly (4-vinyl biphenyl) was studied at different intervals of irradiation time and in presence of air. ...The effect of UV irradiation and blending with phthalate and terephthalate plasticizers on the photo-stability of Poly (4-vinyl biphenyl) was studied at different intervals of irradiation time and in presence of air. The increase in irradiation time on the photodegradation of polymer thin films caused a change in the intensity and shape of the fluorescence band. It has been found that the stability of the polymer decreases with the increase of irradiation time, and to increases with the increase of the amount of added phthalate and terephthalate plasticizers, which is evidence of polymer photodegradation. The FT-IR spectra of irradiated pure and blended polymer with phthalate and terephthalate plasticizers showed a decrease in some absorption bands and increase in the other bands, this is also another factor for the occurrence of photo degradation of the irradiated polymer. The increase in the intensity of absorption of carbonyl and hydroxyl region, indicates a possible photogegradation of polymeric chains and the formation of alcohols, aliphatic ketones and to the increase in the number of (C=C) that resulted from hydrogen abstraction during chains-scission.展开更多
Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery ...Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery and morphological changes following thoracic contusive spinal cord injury. After a 7-day recovery period after spinal cord injury, mice were assigned to either a trained group(10 weeks of voluntary running wheel or forced treadmill exercise) or an untrained group. Bi-weekly assessments revealed that the exercise-trained group, particularly the voluntary wheel exercise subgroup, displayed significantly improved locomotor recovery, more plasticity of dopaminergic and serotonin modulation compared with the untrained group. Additionally, exercise interventions led to gait pattern restoration and enhanced transcranial magnetic motor-evoked potentials. Despite consistent injury areas across groups, exercise training promoted terminal innervation of descending axons. In summary, voluntary wheel exercise shows promise for enhancing outcomes after thoracic contusive spinal cord injury, emphasizing the role of exercise modality in promoting recovery and morphological changes in spinal cord injuries. Our findings will influence future strategies for rehabilitation exercises, restoring functional movement after spinal cord injury.展开更多
The microstructural evolution of a cold-rolled and intercritical annealed medium-Mn steel(Fe-0.10C-5Mn)was investigated during uniaxial tensile testing.In-situ observations under scanning electron microscopy,transmiss...The microstructural evolution of a cold-rolled and intercritical annealed medium-Mn steel(Fe-0.10C-5Mn)was investigated during uniaxial tensile testing.In-situ observations under scanning electron microscopy,transmission electron microscopy,and X-ray diffraction analysis were conducted to characterize the progressive transformation-induced plasticity process and associated fracture initiation mechanisms.These findings were discussed with the local strain measurements via digital image correlation.The results indicated that Lüders band formation in the steel was limited to 1.5%strain,which was mainly due to the early-stage martensitic phase transformation of a very small amount of the less stable large-sized retained austenite(RA),which led to localized stress concentrations and strain hardening and further retardation of yielding.The small-sized RA exhibited high stability and progressively transformed into martensite and contributed to a stably extended Portevin-Le Chatelier effect.The volume fraction of RA gradually decreased from 26.8%to 8.2%prior to fracture.In the late deformation stage,fracture initiation primarily occurred at the austenite/martensite and ferrite/martensite interfaces and the ferrite phase.展开更多
Peripheral nerve injuries result in the rapid degeneration of distal nerve segments and immediate loss of motor and sensory functions;behavioral recovery is typically poor.We used a plasmalemmal fusogen,polyethylene g...Peripheral nerve injuries result in the rapid degeneration of distal nerve segments and immediate loss of motor and sensory functions;behavioral recovery is typically poor.We used a plasmalemmal fusogen,polyethylene glycol(PEG),to immediately fuse closely apposed open ends of severed proximal and distal axons in rat sciatic nerves.We have previously reported that sciatic nerve axons repaired by PEG-fusion do not undergo Wallerian degeneration,and PEG-fused animals exhibit rapid(within 2–6 weeks)and extensive locomotor recovery.Furthermore,our previous report showed that PEG-fusion of severed sciatic motor axons was non-specific,i.e.,spinal motoneurons in PEG-fused animals were found to project to appropriate as well as inappropriate target muscles.In this study,we examined the consequences of PEG-fusion for sensory axons of the sciatic nerve.Young adult male and female rats(Sprague–Dawley)received either a unilateral single cut or ablation injury to the sciatic nerve and subsequent repair with or without(Negative Control)the application of PEG.Compound action potentials recorded immediately after PEG-fusion repair confirmed conduction across the injury site.The success of PEG-fusion was confirmed through Sciatic Functional Index testing with PEG-fused animals showing improvement in locomotor function beginning at 35 days postoperatively.At 2–42 days postoperatively,we anterogradely labeled sensory afferents from the dorsal aspect of the hindpaw following bilateral intradermal injection of wheat germ agglutinin conjugated horseradish peroxidase.PEG-fusion repair reestablished axonal continuity.Compared to unoperated animals,labeled sensory afferents ipsilateral to the injury in PEG-fused animals were found in the appropriate area of the dorsal horn,as well as inappropriate mediolateral and rostrocaudal areas.Unexpectedly,despite having intact peripheral nerves,similar reorganizations of labeled sensory afferents were also observed contralateral to the injury and repair.This central reorganization may contribute to the improved behavioral recovery seen after PEG-fusion repair,supporting the use of this novel repair methodology over currently available treatments.展开更多
Poly(butylene adipate-terephthalate)(PBAT),as one of the most common and promising biodegradable plastics,has been widely used in agriculture,packaging,and other industries due to its strong biodegradability propertie...Poly(butylene adipate-terephthalate)(PBAT),as one of the most common and promising biodegradable plastics,has been widely used in agriculture,packaging,and other industries due to its strong biodegradability properties.It is well known that PBAT suffers a series of natural weathering,mechanical wear,hydrolysis,photochemical transformation,and other abiotic degradation processes before being biodegraded.Therefore,it is particularly important to understand the role of abiotic degradation in the life cycle of PBAT.Since the abiotic degradation of PBAT has not been systematically summarized,this review aims to summarize the mechanisms and main factors of the three major abiotic degradation pathways(hydrolysis,photochemical transformation,and thermochemical degradation)of PBAT.It was found that all of them preferentially destroy the chemical bonds with higher energy(especially C-O and C=O)of PBAT,which eventually leads to the shortening of the polymer chain and then leads to reduction in molecular weight.The main factors affecting these abiotic degradations are closely related to the energy or PBAT structure.These findings provide important theoretical and practical guidance for identifying effective methods for PBAT waste management and proposing advanced schemes to regulate the degradation rate of PBAT.展开更多
Agricultural practices significantly contribute to greenhouse gas(GHG)emissions,necessitating cleaner production technologies to reduce environmental pressure and achieve sustainable maize production.Plastic film mulc...Agricultural practices significantly contribute to greenhouse gas(GHG)emissions,necessitating cleaner production technologies to reduce environmental pressure and achieve sustainable maize production.Plastic film mulching is commonly used in the Loess Plateau region.Incorporating slow-release fertilizers as a replacement for urea within this practice can reduce nitrogen losses and enhance crop productivity.Combining these techniques represents a novel agricultural approach in semi-arid areas.However,the impact of this integration on soil carbon storage(SOCS),carbon footprint(CF),and economic benefits has received limited research attention.Therefore,we conducted an eight-year study(2015-2022)in the semi-arid northwestern region to quantify the effects of four treatments[urea supplied without plastic film mulching(CK-U),slow-release fertilizer supplied without plastic film mulching(CK-S),urea supplied with plastic film mulching(PM-U),and slow-release fertilizer supplied with plastic film mulching(PM-S)]on soil fertility,economic and environmental benefits.The results revealed that nitrogen fertilizer was the primary contributor to total GHG emissions(≥71.97%).Compared to other treatments,PM-S increased average grain yield by 12.01%-37.89%,water use efficiency by 9.19%-23.33%,nitrogen accumulation by 27.07%-66.19%,and net return by 6.21%-29.57%.Furthermore,PM-S decreased CF by 12.87%-44.31%and CF per net return by 14.25%-41.16%.After eight years,PM-S increased SOCS(0-40 cm)by 2.46%,while PM-U decreased it by 7.09%.These findings highlight the positive effects of PM-S on surface soil fertility,economic gains,and environmental benefits in spring maize production on the Loess Plateau,underscoring its potential for widespread adoption and application.展开更多
To better understand the migration behavior of plastic fragments in the environment,development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary.Howeve...To better understand the migration behavior of plastic fragments in the environment,development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary.However,most of the studies had focused only on colored plastic fragments,ignoring colorless plastic fragments and the effects of different environmental media(backgrounds),thus underestimating their abundance.To address this issue,the present study used near-infrared spectroscopy to compare the identification of colored and colorless plastic fragments based on partial least squares-discriminant analysis(PLS-DA),extreme gradient boost,support vector machine and random forest classifier.The effects of polymer color,type,thickness,and background on the plastic fragments classification were evaluated.PLS-DA presented the best and most stable outcome,with higher robustness and lower misclassification rate.All models frequently misinterpreted colorless plastic fragments and its background when the fragment thickness was less than 0.1mm.A two-stage modeling method,which first distinguishes the plastic types and then identifies colorless plastic fragments that had been misclassified as background,was proposed.The method presented an accuracy higher than 99%in different backgrounds.In summary,this study developed a novel method for rapid and synchronous identification of colored and colorless plastic fragments under complex environmental backgrounds.展开更多
Dislocations and disclinations are fundamental topological defects within crystals,which determine the mechanical properties of metals and alloys.Despite their important roles in multiple physical mechanisms,e.g.,dyna...Dislocations and disclinations are fundamental topological defects within crystals,which determine the mechanical properties of metals and alloys.Despite their important roles in multiple physical mechanisms,e.g.,dynamic recovery and grain boundary mediated plasticity,the intrinsic coupling and correlation between disclinations and dislocations,and their impacts on the deformation behavior of metallic materials still remain obscure,partially due to the lack of a theoretical tool to capture the rotational nature of disclinations.By using a Lie-algebra-based theoretical framework,we obtain a general equation to quantify the intrinsic coupling of disclinations and dislocations.Through quasi in-situ electron backscatter diffraction characterizations and disclination/dislocation density analyses in Mg alloys,the generation,coevolution and reactions of disclinations and dislocations during dynamic recovery and superplastic deformation have been quantitatively analyzed.It has been demonstrated that the obtained governing equation can capture multiple physical processes associated with mechanical deformation of metals,e.g.,grain rotation and grain boundary migration,at both room temperature and high temperature.By establishing the disclination-dislocation coupling equation within a Lie algebra description,our work provides new insights for exploring the coevolution and reaction of disclinations/dislocations,with profound implications for elucidating the microstructure-property relationship and underlying deformation mechanisms in metallic materials.展开更多
With increasing water depth,marine drilling conductors exhibit higher slenderness ratios,significantly reducing their resistance to environmental loads in Arctic waters.These conductors,when subjected to combined wind...With increasing water depth,marine drilling conductors exhibit higher slenderness ratios,significantly reducing their resistance to environmental loads in Arctic waters.These conductors,when subjected to combined wind,current,and ice loads,may experience substantial horizontal displacements and bending moments,potentially compromising off-shore operational safety and wellhead stability.Additionally,soil disturbance near the mudline diminishes the conductor’s bearing capacity,potentially rendering it inadequate for wellhead support and increasing operational risks.This study introduces a static analysis model based on plastic hinge theory to evaluate conductor survivability.The conductor analysis divides the structure into three segments:above waterline,submerged,and embedded below mudline.An idealized elastic-plastic p-y curve model characterizes soil behavior beneath the mudline,while the finite difference method(FDM)analyzes the conductor’s mechanical response under complex pile-head boundary conditions.Numerical simulations using ABAQUS validate the plastic hinge approach against conventional methods,confirming its accuracy in predicting structural performance.These results provide valuable insights for optimizing installation depths and bearing capacity designs of marine drilling conductors in ice-prone regions.展开更多
Brain plasticity-A universal tool with many variations:The study of brain plasticity has been gaining interest since almost a century and has now reached a huge amount of information(>80,000 results in PubMed).Over...Brain plasticity-A universal tool with many variations:The study of brain plasticity has been gaining interest since almost a century and has now reached a huge amount of information(>80,000 results in PubMed).Overall,different types of plasticity,including stem cell-driven genesis of new neurons(adult neurogenesis),cells in arrested maturation(dormant neurons),neuro-glial and synaptic plasticity,can coexist and contribute to grant plastic changes in the brain,from a cellular to system level(Benedetti and Couillard-Despres,2022;Bonfanti et al.,2023).展开更多
Cells,tissues,and organs are constantly subjected to the action of mechanical forces from the extracellular environment-and the nervous system is no exception.Cell-intrinsic properties such as membrane lipid compositi...Cells,tissues,and organs are constantly subjected to the action of mechanical forces from the extracellular environment-and the nervous system is no exception.Cell-intrinsic properties such as membrane lipid composition,abundance of mechanosensors,and cytoskeletal dynamics make cells more or less likely to sense these forces.Intrinsic and extrinsic cues are integrated by cells and this combined information determines the rate and dynamics of membrane protrusion growth or retraction(Yamada and Sixt,2019).Cell protrusions are extensions of the plasma membrane that play crucial roles in diverse contexts such as cell migration and neuronal synapse formation.In the nervous system,neurons are highly dynamic cells that can change the size and number of their pre-and postsynaptic elements(called synaptic boutons and dendritic spines,respectively),in response to changes in the levels of synaptic activity through a process called plasticity.Synaptic plasticity is a hallmark of the nervous system and is present throughout our lives,being required for functions like memory formation or the learning of new motor skills(Minegishi et al.,2023;Pillai and Franze,2024).展开更多
基金funded by IAEA Coordinated Research Project F22081.
文摘Conventional bioplastic production from seaweed often relies on extraction processes that are costly,time-consuming,and yield limited product.This study presents a direct fabrication method using Gracilaria sp.,a red seaweed rich in polysaccharides,to produce bioplastic films without the need for extraction.Sorbitol was incorporated as a plasticizer at concentrations of 0%–10%(w/w)to modify film characteristics.Thermal analysis revealed improved stability at moderate sorbitol levels(5%–7%),while excessive plasticizer slightly reduced thermal resistance.Mechanical testing showed that sorbitol increased film flexibility and elongation at break,though tensile strength and stiffness declined.Tear strength followed a non-linear trend,with improvement observed at higher sorbitol concentrations.Seal strength also increased,peaking at 7%,indicating stronger interfacial bonding between film layers.Biodegradation tests demonstrated accelerated decomposition with increased sorbitol content,achieving complete degradation within 30 days at 10% concentration.Color analysis showed increased brightness and reduced yellowing,enhancing the visual quality of the films.These results confirm that direct conversion of bioplastic is both feasible and effective.Sorbitol plays a key role in tuning film properties,offering a low-cost,scalable pathway to biodegradable materials suitable for environmentally friendly packaging applications.
基金financially supported by the National Natural Science Foundation of China (No.U20A20256)。
文摘The chain dynamics heterogeneity of the poly(vinyl butyral)(PVB) plasticized by triethylene glycol bis(2-ethylhexa noate)(TEG-EH) was investigated by various solid-state NMR techniques.The plasticized PVB shows two domains in distinct molecular dynamics differences,namely,rigid and soft domains,where the latter is the plasticizer-rich domain.The time domain low field NMR was first used to investigate the dynamics heterogeneity of the plasticized PVB,and the results show the decreasing activated energy of components in the soft domain of plasticized PVB(E_a=20.2 kJ/mol) as compared with that of the pristine one(E_a=24.3 kJ/mol).Detailed dynamics heterogeneity was obtained by high-field NMR with site-specific features.The quadrupole-echo ~2H-NMR was adopted to elucidate the dynamics heterogeneity of the vinyl alcohol(VA) units,where only the hydroxyl group of VA is deuterated.The ~1H-^(13)C WISE NMR spectra show that there is not much difference in the mobility of the VB unit in PVB with and without plasticizer,whereas the glass transition temperature differed by approximately 53℃.This is further supported by Torchia's T_1 relaxation measurements.The origin of such an unusual phenomenon is attributed to the critical role of the remaining VA(~22%) in the soft domain,where the VA units locally aggregate through hydrogen bonding.Also,the existence of a mobility gradient in the VB unit has been demonstrated.Moreover,the mobility difference for VB with different stereo-geometry(meso or racemic conformation) is observed for the first time.This indicates the importance of modulating the ratio of meso over racemic VB for controlling the macroscopic perfo rmance of PVB.
基金financially supported by the Indonesia Endowment Fund for Education(LPDP)scholarshipfunded by the Ministry of Finance,Republic of Indonesia(award number 202112210108100).
文摘Commercial lithium-ion batteries(LIBs)use polyolefins as separators.This has led to increased research on separators composed of renewable materials such as cellulose and its derivatives.In this study,the ionic conductivity of cellulose acetate(CA)polymer electrolyte membranes was enhanced via plasticization with citric acid and succinonitrile.The primary objective of this study was to evaluate the effectiveness of these plasticizers in improving cellulose-based separator membranes in LIBs.CA membranes were fabricated using solution casting technique and then plasticized with various concentrations of plasticizers.The structural,thermal,and electrochemical properties of the resulting membranes were characterized using Fourier Transform infrared(FTIR)spectroscopy,X-Ray Diffraction(XRD),Differential Scanning Calorimetry(DSC),Thermogravimetric Analysis(TGA),and Electrochemical Impedance Spectroscopy(EIS).The FTIR and XRD results confirmed the successful incorporation of citric acid and succinonitrile into the polymer matrix,while the TGA analysis demonstrated the enhanced thermal stability of the plasticized membranes.The shift in the glass transition temperature was determined by DSC analysis.Most notably,the EIS results revealed a significant increase in ionic conductivity,achieving a maximum of 2.7×10^(-5) S/cm at room temperature.This improvement was attributed to the effect of plasticizers,which facilitated the dissociation of lithium salts and increase the mobility of the lithium ions.The ionic conductivities of plasticized CA membranes are better than those of unmodified CA membranes and commercially available Celgard separator membranes:4.7×10^(-6) and 2.1×10^(-7) S/cm,respectively.These findings suggest that citric acid and succinonitrile are effective plasticizers for cellulose acetate membranes,making them promising substitutes for commercial polyolefin separators in LIB applications.
基金Project supported by the National Natural Science Foundation of China(No.11572349)the Natural Science Foundation of Hunan Province(No.2018JJ3606),China。
文摘Nitrate ester plasticized polyether(NEPE)is a kind of high-energy solid propellant that has both good mechanical properties and high specific impulse.However,its unique composition makes its combustion mechanism different from both double-base propellants and composite propellants.In order to study the combustion mechanism of NEPE propellants,we improved the free radical cracking model of previous research to make it capable of predicting the burning rate of NEPE propellants.To study the combustion characteristics and provide data support for the model,an experimental system was built and four kinds of NEPE propellants with different compositions and grain size distributions were tested.The results show that our modified model can reflect the combustion characteristics of NEPE propellants with an acceptable accuracy.The difference between the model and the experimental data is mainly caused by uncertain environmental factors and the ignorance of interactions between components.Both the experimental data and the results predicted by the model show that increasing the backpressure helps to increase the burning rate of NEPE propellants.Furthermore,the grain size of the oxidizer inside the NEPE propellant has a more severe impact on the burning rate but a lighter impact on the burning rate pressure exponent in comparison with the grain size of aluminum.For aluminum-free NEPE propellants,the reaction in the gas phase is dominant in the combustion process while adding aluminum into the propellant makes the solid phase dominant in the final stage.The combustion of fine aluminum particles near the burning surface generates heat feedback to the burning surface which evidently influences the surface temperature.However,the agglomeration of coarse aluminum particles has little effect on the burning surface temperature.
文摘The cation—conductive blends plasticized with propylene carbonate were prepared. The blends exhibited good mechanical strength and single—cation conduction over a wide range of plasticizer composition. The plasticizer not only increases the conductivity of the blends but also decreases the electrochemical interface resistance between the blend and lithium electrode. The carrier in the blends obviously grows in number.
基金Funded by the Natural Science Foundation of Hubei Provincial Science&Technologies Department(2010CDB04604)
文摘Novel microcellular foams using thin plasticized PC sheet were prepared by compression molding. The measurement results showed that T of plasticized PC was decreased and the molecular chain mobility was increased. Decrease in T and increase in chains mobility were contributed to the widen of foaming temperature window. Effects of processing conditions on cell size, cell density and relative density were also investigated. The experimental results show that the temperature, tributyl citrate and foaming agent content have more effects on the structures and morphology of the plasticized PC microcellular foam. Effects of experimental conditions on cell size distribution have also been discussed.
文摘The photodegradation of irradiated thin films of poly (para-methylstyrene) with 265 nm radiations in the presence of airand as a function of irradiation time has been studied using UV-VIS, fluorescence and FT-IR Spectroscopic techniques. The influence of phthalate and terephthalate plasticizers on stability of poly (para-methylstyrene) towards irradiations was also investigated. Blending with phthalate plasticizers was found to cause a higher efficiency of photodegradation than that obtained in doping with terephthalate plasticizers. The intensity of absorption was also found to increase with time of irradiation and in change in the shape of the spectra at longer wavelength, thus indicating a possibility of photodegradation of polymer chains. The analysis of the FT-IR spectra of the irradiated and non-irradiated samples, shows a predominant absorption associated with carbonyl compounds with 1740 cm-1. In addition, the observed increase in the intensities of the carbonyl and hydroxyl regions of the FT-IR spectra, have provided an evidence for the photodegradation as well as photo-oxidation of polymeric chains. The presence of the plasticizer in the polymer backbone was found to accelerate the photodegradation of polymeric chains.
文摘Blends of gelatin(Ge)plasticized with varying amounts of glycerol(Gly),buffer solution pH 10 and epoxidized soybean oil(ESO)to enhance hydrophobicity were prepared by mixing and injection-molding.Blends were characterized by rheological tests and microscopy to select optimal conditions for scaling up their processing.The effect of each component on rheological response was analyzed using parallel plate geometry.Coating of gelatin specimens with PDMS during rheological tests led to reliable and reproducible results since water evaporation was prevented.A gradual increment in ESO concentration led to blends with increased degree of phase separation,as evidenced by optical and confocal microscopy.Limited compatibility between ESO and Ge increased viscosity at high ESO levels,but up to 10%Gly could be replaced with ESO without a significant variation of rheological behavior.
文摘The effect of UV irradiation and blending with phthalate and terephthalate plasticizers on the photo-stability of Poly (4-vinyl biphenyl) was studied at different intervals of irradiation time and in presence of air. The increase in irradiation time on the photodegradation of polymer thin films caused a change in the intensity and shape of the fluorescence band. It has been found that the stability of the polymer decreases with the increase of irradiation time, and to increases with the increase of the amount of added phthalate and terephthalate plasticizers, which is evidence of polymer photodegradation. The FT-IR spectra of irradiated pure and blended polymer with phthalate and terephthalate plasticizers showed a decrease in some absorption bands and increase in the other bands, this is also another factor for the occurrence of photo degradation of the irradiated polymer. The increase in the intensity of absorption of carbonyl and hydroxyl region, indicates a possible photogegradation of polymeric chains and the formation of alcohols, aliphatic ketones and to the increase in the number of (C=C) that resulted from hydrogen abstraction during chains-scission.
基金supported by the NIH (R01NS103481, R01NS111776, and R01NS131489)Indiana Department of Health (ISDH58180)(all to WW)。
文摘Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery and morphological changes following thoracic contusive spinal cord injury. After a 7-day recovery period after spinal cord injury, mice were assigned to either a trained group(10 weeks of voluntary running wheel or forced treadmill exercise) or an untrained group. Bi-weekly assessments revealed that the exercise-trained group, particularly the voluntary wheel exercise subgroup, displayed significantly improved locomotor recovery, more plasticity of dopaminergic and serotonin modulation compared with the untrained group. Additionally, exercise interventions led to gait pattern restoration and enhanced transcranial magnetic motor-evoked potentials. Despite consistent injury areas across groups, exercise training promoted terminal innervation of descending axons. In summary, voluntary wheel exercise shows promise for enhancing outcomes after thoracic contusive spinal cord injury, emphasizing the role of exercise modality in promoting recovery and morphological changes in spinal cord injuries. Our findings will influence future strategies for rehabilitation exercises, restoring functional movement after spinal cord injury.
基金supported by the National Key R&D Program of China(No.2017YFB0304402)。
文摘The microstructural evolution of a cold-rolled and intercritical annealed medium-Mn steel(Fe-0.10C-5Mn)was investigated during uniaxial tensile testing.In-situ observations under scanning electron microscopy,transmission electron microscopy,and X-ray diffraction analysis were conducted to characterize the progressive transformation-induced plasticity process and associated fracture initiation mechanisms.These findings were discussed with the local strain measurements via digital image correlation.The results indicated that Lüders band formation in the steel was limited to 1.5%strain,which was mainly due to the early-stage martensitic phase transformation of a very small amount of the less stable large-sized retained austenite(RA),which led to localized stress concentrations and strain hardening and further retardation of yielding.The small-sized RA exhibited high stability and progressively transformed into martensite and contributed to a stably extended Portevin-Le Chatelier effect.The volume fraction of RA gradually decreased from 26.8%to 8.2%prior to fracture.In the late deformation stage,fracture initiation primarily occurred at the austenite/martensite and ferrite/martensite interfaces and the ferrite phase.
基金supported by the Department of Defense AFIRMⅢW81XWH-20-2-0029 grant subcontractLone Star Paralysis gift,UT POC19-1774-13 grant+1 种基金Neuraptive Therapeutics Inc.26-7724-56 grantNational Institutes of Health R01-NS128086(all to GDB)。
文摘Peripheral nerve injuries result in the rapid degeneration of distal nerve segments and immediate loss of motor and sensory functions;behavioral recovery is typically poor.We used a plasmalemmal fusogen,polyethylene glycol(PEG),to immediately fuse closely apposed open ends of severed proximal and distal axons in rat sciatic nerves.We have previously reported that sciatic nerve axons repaired by PEG-fusion do not undergo Wallerian degeneration,and PEG-fused animals exhibit rapid(within 2–6 weeks)and extensive locomotor recovery.Furthermore,our previous report showed that PEG-fusion of severed sciatic motor axons was non-specific,i.e.,spinal motoneurons in PEG-fused animals were found to project to appropriate as well as inappropriate target muscles.In this study,we examined the consequences of PEG-fusion for sensory axons of the sciatic nerve.Young adult male and female rats(Sprague–Dawley)received either a unilateral single cut or ablation injury to the sciatic nerve and subsequent repair with or without(Negative Control)the application of PEG.Compound action potentials recorded immediately after PEG-fusion repair confirmed conduction across the injury site.The success of PEG-fusion was confirmed through Sciatic Functional Index testing with PEG-fused animals showing improvement in locomotor function beginning at 35 days postoperatively.At 2–42 days postoperatively,we anterogradely labeled sensory afferents from the dorsal aspect of the hindpaw following bilateral intradermal injection of wheat germ agglutinin conjugated horseradish peroxidase.PEG-fusion repair reestablished axonal continuity.Compared to unoperated animals,labeled sensory afferents ipsilateral to the injury in PEG-fused animals were found in the appropriate area of the dorsal horn,as well as inappropriate mediolateral and rostrocaudal areas.Unexpectedly,despite having intact peripheral nerves,similar reorganizations of labeled sensory afferents were also observed contralateral to the injury and repair.This central reorganization may contribute to the improved behavioral recovery seen after PEG-fusion repair,supporting the use of this novel repair methodology over currently available treatments.
基金supported by the National Key R&D Program of China(No.2022YFC3901800)the National Natural Science Foundation of China(No.22176041)Guangzhou Science and Technology Planning Project(No.2023A04J0918)。
文摘Poly(butylene adipate-terephthalate)(PBAT),as one of the most common and promising biodegradable plastics,has been widely used in agriculture,packaging,and other industries due to its strong biodegradability properties.It is well known that PBAT suffers a series of natural weathering,mechanical wear,hydrolysis,photochemical transformation,and other abiotic degradation processes before being biodegraded.Therefore,it is particularly important to understand the role of abiotic degradation in the life cycle of PBAT.Since the abiotic degradation of PBAT has not been systematically summarized,this review aims to summarize the mechanisms and main factors of the three major abiotic degradation pathways(hydrolysis,photochemical transformation,and thermochemical degradation)of PBAT.It was found that all of them preferentially destroy the chemical bonds with higher energy(especially C-O and C=O)of PBAT,which eventually leads to the shortening of the polymer chain and then leads to reduction in molecular weight.The main factors affecting these abiotic degradations are closely related to the energy or PBAT structure.These findings provide important theoretical and practical guidance for identifying effective methods for PBAT waste management and proposing advanced schemes to regulate the degradation rate of PBAT.
基金supported by the National Natural Science Foundation of China(No.32071980)the Key Projects of Shaanxi Agricultural Collaborative Innovation and Extension Alliance(No.LMZD202201)+1 种基金the Key R&D Project in Shaanxi Province(No.2021LLRH-07)Shaanxi Natural Scientific Basic Research Program project(No.2022JQ-157).
文摘Agricultural practices significantly contribute to greenhouse gas(GHG)emissions,necessitating cleaner production technologies to reduce environmental pressure and achieve sustainable maize production.Plastic film mulching is commonly used in the Loess Plateau region.Incorporating slow-release fertilizers as a replacement for urea within this practice can reduce nitrogen losses and enhance crop productivity.Combining these techniques represents a novel agricultural approach in semi-arid areas.However,the impact of this integration on soil carbon storage(SOCS),carbon footprint(CF),and economic benefits has received limited research attention.Therefore,we conducted an eight-year study(2015-2022)in the semi-arid northwestern region to quantify the effects of four treatments[urea supplied without plastic film mulching(CK-U),slow-release fertilizer supplied without plastic film mulching(CK-S),urea supplied with plastic film mulching(PM-U),and slow-release fertilizer supplied with plastic film mulching(PM-S)]on soil fertility,economic and environmental benefits.The results revealed that nitrogen fertilizer was the primary contributor to total GHG emissions(≥71.97%).Compared to other treatments,PM-S increased average grain yield by 12.01%-37.89%,water use efficiency by 9.19%-23.33%,nitrogen accumulation by 27.07%-66.19%,and net return by 6.21%-29.57%.Furthermore,PM-S decreased CF by 12.87%-44.31%and CF per net return by 14.25%-41.16%.After eight years,PM-S increased SOCS(0-40 cm)by 2.46%,while PM-U decreased it by 7.09%.These findings highlight the positive effects of PM-S on surface soil fertility,economic gains,and environmental benefits in spring maize production on the Loess Plateau,underscoring its potential for widespread adoption and application.
基金supported by the National Natural Science Foundation of China(No.22276139)the Shanghai’s Municipal State-owned Assets Supervision and Administration Commission(No.2022028).
文摘To better understand the migration behavior of plastic fragments in the environment,development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary.However,most of the studies had focused only on colored plastic fragments,ignoring colorless plastic fragments and the effects of different environmental media(backgrounds),thus underestimating their abundance.To address this issue,the present study used near-infrared spectroscopy to compare the identification of colored and colorless plastic fragments based on partial least squares-discriminant analysis(PLS-DA),extreme gradient boost,support vector machine and random forest classifier.The effects of polymer color,type,thickness,and background on the plastic fragments classification were evaluated.PLS-DA presented the best and most stable outcome,with higher robustness and lower misclassification rate.All models frequently misinterpreted colorless plastic fragments and its background when the fragment thickness was less than 0.1mm.A two-stage modeling method,which first distinguishes the plastic types and then identifies colorless plastic fragments that had been misclassified as background,was proposed.The method presented an accuracy higher than 99%in different backgrounds.In summary,this study developed a novel method for rapid and synchronous identification of colored and colorless plastic fragments under complex environmental backgrounds.
基金Financial supports from the National Natural Science Foundation of China(Nos.52171116,U22A20109,52334010 and T2325013)are greatly acknowledgedPartial financial support came from The Program for the Central University Youth Innovation Team,and the Fundamental Research Funds for the Central Universities,JLU.
文摘Dislocations and disclinations are fundamental topological defects within crystals,which determine the mechanical properties of metals and alloys.Despite their important roles in multiple physical mechanisms,e.g.,dynamic recovery and grain boundary mediated plasticity,the intrinsic coupling and correlation between disclinations and dislocations,and their impacts on the deformation behavior of metallic materials still remain obscure,partially due to the lack of a theoretical tool to capture the rotational nature of disclinations.By using a Lie-algebra-based theoretical framework,we obtain a general equation to quantify the intrinsic coupling of disclinations and dislocations.Through quasi in-situ electron backscatter diffraction characterizations and disclination/dislocation density analyses in Mg alloys,the generation,coevolution and reactions of disclinations and dislocations during dynamic recovery and superplastic deformation have been quantitatively analyzed.It has been demonstrated that the obtained governing equation can capture multiple physical processes associated with mechanical deformation of metals,e.g.,grain rotation and grain boundary migration,at both room temperature and high temperature.By establishing the disclination-dislocation coupling equation within a Lie algebra description,our work provides new insights for exploring the coevolution and reaction of disclinations/dislocations,with profound implications for elucidating the microstructure-property relationship and underlying deformation mechanisms in metallic materials.
基金financially supported by the National Natural Science Foundation of China(Grant No.U22B20126)the National Key Research and Development Program of China(Grant No.2022YFC2806100).
文摘With increasing water depth,marine drilling conductors exhibit higher slenderness ratios,significantly reducing their resistance to environmental loads in Arctic waters.These conductors,when subjected to combined wind,current,and ice loads,may experience substantial horizontal displacements and bending moments,potentially compromising off-shore operational safety and wellhead stability.Additionally,soil disturbance near the mudline diminishes the conductor’s bearing capacity,potentially rendering it inadequate for wellhead support and increasing operational risks.This study introduces a static analysis model based on plastic hinge theory to evaluate conductor survivability.The conductor analysis divides the structure into three segments:above waterline,submerged,and embedded below mudline.An idealized elastic-plastic p-y curve model characterizes soil behavior beneath the mudline,while the finite difference method(FDM)analyzes the conductor’s mechanical response under complex pile-head boundary conditions.Numerical simulations using ABAQUS validate the plastic hinge approach against conventional methods,confirming its accuracy in predicting structural performance.These results provide valuable insights for optimizing installation depths and bearing capacity designs of marine drilling conductors in ice-prone regions.
基金supported by Progetto Trapezio,Compagnia di San Paolo(67935-2021.2174)to LB,Fondazione CRT(Cassa di Risparmio di Torino,RF=2022.0618)to LB。
文摘Brain plasticity-A universal tool with many variations:The study of brain plasticity has been gaining interest since almost a century and has now reached a huge amount of information(>80,000 results in PubMed).Overall,different types of plasticity,including stem cell-driven genesis of new neurons(adult neurogenesis),cells in arrested maturation(dormant neurons),neuro-glial and synaptic plasticity,can coexist and contribute to grant plastic changes in the brain,from a cellular to system level(Benedetti and Couillard-Despres,2022;Bonfanti et al.,2023).
基金supported by PTDC-01778/2022-NeuroDev3D,iNOVA4Health(UIDB/04462/2020 and UIDP/04462/2020)LS4FUTURE(LA/P/0087/2020)。
文摘Cells,tissues,and organs are constantly subjected to the action of mechanical forces from the extracellular environment-and the nervous system is no exception.Cell-intrinsic properties such as membrane lipid composition,abundance of mechanosensors,and cytoskeletal dynamics make cells more or less likely to sense these forces.Intrinsic and extrinsic cues are integrated by cells and this combined information determines the rate and dynamics of membrane protrusion growth or retraction(Yamada and Sixt,2019).Cell protrusions are extensions of the plasma membrane that play crucial roles in diverse contexts such as cell migration and neuronal synapse formation.In the nervous system,neurons are highly dynamic cells that can change the size and number of their pre-and postsynaptic elements(called synaptic boutons and dendritic spines,respectively),in response to changes in the levels of synaptic activity through a process called plasticity.Synaptic plasticity is a hallmark of the nervous system and is present throughout our lives,being required for functions like memory formation or the learning of new motor skills(Minegishi et al.,2023;Pillai and Franze,2024).
