Wet Environment Research Articles

Rain and potential evapotranspiration are the main drivers of yield for wheat and barley in southern Australia: insights from 12 years of National Variety Trials

Context Water is widely assumed to be the factor most limiting the growth of annual crops in rainfed environments, but this is rarely tested at sub-continental scale. Aims Our study aimed to determine the key environmental and management variables influencing the yield of wheat and barley in the grain-production regions of southern Australia, using data from National Variety Trials. Methods We used generalised additive models to determine the importance of climatic and management variables on wheat and barley grain yield. We determined the effects of the best one, two or three variables and their interactions. Key results The aridity index, defined as the ratio of cumulative rainfall to potential evapotranspiration, was the single strongest determinant of grain yield for both crops. Model performance was further improved by separating the aridity index into pre-seasonal and seasonal components. Interestingly, other variables that might be expected to influence yield, such as nitrogen fertilisation and extreme temperatures, had relatively minor effects. A comparison between data collected over two 6-year periods showed that there had been yield gains and increased water-use efficiency with time, especially in wetter environments. Conclusions Our findings illustrate the importance of water availability for grain production in this region and suggest opportunities for benchmarking and yield prediction through use of readily available climate data. Implications Our study reinforces the importance of factors such as water-use efficiency and drought tolerance as goals for cultivar development and agronomic research in wheat and barley. It also highlights the potential of National Variety Trial data as a resource for understanding grain production systems and climate resilience. Further work could explore the value of additional variables and improved weather data.

Genetic response of a perennial grass to warm and wet environments interacts and is associated with trait means as well as plasticity.

Potential for rapid evolution is an important mechanism allowing species to adapt to changing climatic conditions. Although such a potential has been largely studied in various short-lived organisms, to what extent we can observe similar patterns in long-lived plant species, which often dominate natural systems, is largely unexplored. We explored potential for rapid evolution in Festuca rubra, long-lived grass with extensive clonal growth dominating in alpine grasslands. We used field sowing experiment simulating expected climate change in our model region. Specifically, we exposed seeds from 5 independent seed sources to novel climatic conditions by shifting them along a natural climatic grid and explored genetic profiles of established seedling after 3 years. Data on genetic profiles of plants selected under different novel conditions indicate that different climate shifts select significantly different pools of genotypes from common seed pools. Increasing soil moisture was more important selective pressure than increasing temperature or interaction of the two climatic factors. This can indicate negative genetic interaction in response to the combined effects, or that the effects of different climates are interactive rather than additive. The selected alleles were found in genomic regions likely affecting function of specific genes or their expression. Many of these were also linked to morphological traits (mainly to trait plasticity) suggesting these changes may have a consequence for plant performance. Overall, these data indicate that even long-lived plant species may experience strong selection by climate, and their populations thus have the potential to rapidly adapt to these novel conditions.

Hydric Environment and Chemical Composition Shape Non-avian Reptile Eggshell Absorption.

The amniotic egg fulfils a critical role in reproduction by serving as an interface between the external environment and the embryo. Because non-avian reptiles are rarely incubated, they must be heated by, and absorb water from, the oviposition site for the developing embryo. The mechanisms by which they absorb sufficient, but not excess, water and how these mechanisms vary with local habitat is largely unknown, despite its significance to their evolution. Here, we first performed histology, Fourier-transform infrared spectroscopy and dynamic vapor sorption experiments to elucidate the mechanisms of eggshell absorption for 56 reptile species. Then, we used phylogenetic comparative analysis to test the hypothesis that the absorptive capacity of reptile eggshells increases with aridity of the environment. We found that water absorption increases in the presence of a superficial mucopolysaccharide layer and decreases with increased calcium content. We found that eggs from arid environments have highly absorbent eggshells, but only in species with weakly calcified shells. Our results suggest that reptile eggshells have over evolutionary time tuned absorptive capacity to environmental moisture level. Since these eggs often must sustain conflicting constraints, they may serve as inspirations for new biomimetic materials, such as water filtering membranes or humidity sensors.

Facile Solvent-Free Fabrication of All-Small-Molecule Supramolecular Photothermal Bioadhesive for Sutureless Wound Closure.

Achieving underwater adhesion possesses a significant challenge, primarily due to the presence of interfacial water, which restricts the potential applications of adhesives. In this study, we present a straightforward and environmentally friendly one-pot approach for synthesizing a solvent-free supramolecular TPFe bioadhesive composed of thioctic acid, proanthocyanidins, and FeCl3. The bioadhesive exhibits excellent biocompatibility and photothermal antibacterial properties and demonstrates effective adhesion on various substrates in both wet and dry environments. Importantly, the adhesive strength of this bioadhesive on steel exceeds 1.2 MPa and that on porcine skin exceeds 100 kPa, which is greater than the adhesive strength of most reported bioadhesives. In addition, the bioadhesive exhibits the ability to effectively halt bleeding, close wounds promptly, and promote wound healing in the rat skin wound model. Therefore, the TPFe bioadhesive has potential as a medical bioadhesive for halting bleeding quickly and promoting wound healing in the biomedical field. This study provides a new idea for the development of bioadhesives with firm wet adhesion.

Glucose-stabilized polyvinyl acetate homopolymer-based wood adhesive: synthesis and characterization

The purpose of this work was to study the synthesis and characterization of an adhesive based on a glucose stabilized polyvinyl acetate homopolymer. Vinyl acetate monomer was stabilised onto liquid glucose using emulsion polymerization, and polymerization happened using potassium persulfate as an initiator. Here, the effects of adding liquid glucose as a stabiliser for adhesives were studied. Therefore, the current research examines whether liquid glucose, introduced at weight-based concentrations of 0.5% and 1.0%, is suitable as a colloid to produce PVAc adhesives for wood. By measuring viscosity, pH, contact angle, differential scanning calorimetry (DSC), and the pencil hardness test of films, the effect of adding liquid glucose as a colloid on physical, thermal, and mechanical properties was investigated. The shear strength of the PVAc homopolymers applied to wood using emulsions with varied liquid glucose concentrations was measured using a universal tensile machine. As the concentration of liquid glucose increased, the viscosity of the adhesives also considerably increased. Water resistance significantly rose when liquid glucose content increased, as was found by measuring the water contact angle. The use of liquid glucose increased the hardness of PVAc films, which was supported by the glass transition temperature. According to EN 204-205, the tensile shear strength with 1.0% of liquid glucose increased by 63.88% and 45.67%, respectively, over a pristine sample after 6 h of bonding in a dry environment and 24 h in a wet environment. The study’s overall conclusion highlights the higher adhesion capability of PVAc emulsion-based adhesives stabilized by liquid glucose.

Implantable Wet‐Adhesive Flexible Electronics with Ultrathin Gelatin Film

AbstractImplantable flexible electronic has attracted significant research interest in various fields. However, it still faces the challenge of simultaneously achieving tight adhesion to tissues in a mildly wet environment and possessing excellent biocompatibility to reduce immune rejection reactions after implantation. Here, a degradable wet‐adhesive flexible electronic device based on liquid metal and ultrathin gelatin film is developed. The ultrathin gelatin film forms numerous hydrogen bonds with tissue in a slightly humid environment, rapidly constructing a wet‐adhesive interface without damaging tissue structure. Inkjet printing is utilized to pattern the mixture of liquid metal and PVP on the surface of the ultrathin gelatin to create flexible patch. With the excellent conductivity of liquid metal, low toxicity, and similarity to natural tissue components of gelatin, flexible patch exhibits outstanding biocompatibility and fatigue resistance. It can be implanted in the body for up to 6 weeks, retaining monitoring capabilities and resisting 1 000 000 cycles of bending fatigue. This study provides a novel strategy for the future development of implantable flexible electronics.

Application of MgO/ZrO2 coating on 309 stainless steel to increase resistance to corrosion at high temperatures and oxidation by an electrochemical method

Abstract 309 stainless steel is one of the steels that have the highest resistance to corrosion and thermal oxidation compared to other steel grades, but it should not be used at temperatures higher than 980°C if there are temperature fluctuations. Additionally, 309 stainless steel is not designed for use in wet environments and has the least corrosion resistance. This study aims to cover 309 stainless steel with MgO/ZrO2 particles using a two-step electroplating deposition method and then sintering to increase its resistance to wet corrosion and oxidation in temperature fluctuations. The intermediate ZrO2 coating makes the outer MgO layer about two times thicker and reduces the corrosion current density. The morphology of the coatings was determined using scanning electron microscopy and X-ray diffraction, and oxidation resistance was determined using cyclic oxidation tests and the wet corrosion test of the corrosion solution. 3.5% NaCl was used. The results showed that the coated samples, due to the use of TiO2 middle layer and MgO protective layer in the electrochemical method, have a 2-fold increase in wet corrosion and an increase in hardness of about 77%, as well as an increase in oxidation resistance of 1.8% compared to the sample without coating. Also, the reason for using the electrochemical deposition method is for better surface smoothness and less porosity of the coating as well as its use on all metals compared to thermal spray methods.

Numerical study on the interface characteristics of gas–liquid falling film flow considering the interface forces

As an energy quality improvement device, an air source heat pump plays an important role in clean heating applications. When operating in a cold and wet environment in winter, the outdoor evaporator will have the problem of frost, which affects the operation efficiency. To solve the frosting problem, the development of frost-free evaporators has attracted more and more attention. The fluctuation characteristics of the gas–liquid interface are the key factors affecting the intensity of gas–liquid heat transfer on the air side of this kind of heat exchanger. Therefore, a mathematical model is established to describe the falling film flow on the surface of the flat finned tube heat exchanger in a closed-type heat source tower. The model takes into account the interfacial tension and interphase friction force between the air flow and the liquid film. On this basis, the fluctuation intensity of the central channel interface during falling film flow with different inlet parameters is studied. It is found that there is a critical value of 1.5 m/s (i.e., Reg = 1643.0) in the air flow rate under the study conditions. When the air flow rate is higher than this velocity, the interface near the gas–liquid outlet fluctuates more frequently and the stability is poor. The distributions of interfacial velocity and pressure are also studied, and the relationship between them and interface fluctuation is analyzed. This paper aims to provide theoretical support for enhanced heat and mass transfer on the air side of finned tube heat exchangers in the closed-type heat source tower.

Investigating Microbial Biosignatures in Aeolian Environments Using Micro-X-Ray: Simulation of PIXL Instrument Analyses at Jezero Crater Onboard the Perseverance Mars 2020 Rover.

Assessing the past habitability of Mars and searching for evidence of ancient life at Jezero crater via the Perseverance rover are the key objectives of NASA's Mars 2020 mission. Onboard the rover, PIXL (Planetary Instrument for X-ray Lithochemistry) is one of the best suited instruments to search for microbial biosignatures due to its ability to characterize chemical composition of fine scale textures in geological targets using a nondestructive technique. PIXL is also the first micro-X-ray fluorescence (XRF) spectrometer onboard a Mars rover. Here, we present guidelines for identifying and investigating a microbial biosignature in an aeolian environment using PIXL-analogous micro-XRF (μXRF) analyses. We collected samples from a modern wet aeolian environment at Padre Island, Texas, that contain buried microbial mats, and we analyzed them using μXRF techniques analogous to how PIXL is being operated on Mars. We show via μXRF technique and microscope images the geochemical and textural variations from the surface to ∼40 cm depth. Microbial mats are associated with heavy-mineral lags and show specific textural and geochemical characteristics that make them a distinct biosignature for this environment. Upon burial, they acquire a diffuse texture due to the expansion and contraction of gas-filled voids, and they present a geochemical signature rich in iron and titanium, which is due to the trapping of heavy minerals. We show that these intrinsic characteristics can be detected via μXRF analyses, and that they are distinct from buried abiotic facies such as cross-stratification and adhesion ripple laminations. We also designed and conducted an interactive survey using the Padre Island μXRF data to explore how different users chose to investigate a biosignature-bearing dataset via PIXL-like sampling strategies. We show that investigating biosignatures via PIXL-like analyses is heavily influenced by technical constraints (e.g., the XRF measurement characteristics) and by the variety of approaches chosen by different scientists. Lessons learned for accurately identifying and characterizing this biosignature in the context of rover-mission constraints include defining relative priorities among measurements, favoring a multidisciplinary approach to the decision-making process of XRF measurements selection, and considering abiotic results to support or discard a biosignature interpretation. Our results provide guidelines for PIXL analyses of potential biosignature on Mars.

The influence of hygrothermal aging on the hoop tensile strength of glass fiber wound polymer composites fabricated via filament winding technique

The study investigates the impact of moisture environment treatment, on the hoop tensile strength (HTS) of glass fiber-reinforced polymer (GFRP) composites, through hygrothermal aging. GFRP cylinders were fabricated with varied parameters—volume fraction, winding angle, and stacking sequences using a filament winding machine. The fabricated samples are subjected to hygrothermal aging using seawater and tap water with oil at 80 °C for 1080 h (45 days). The HTS tests were performed on unaged and aged samples. There was a reduction in HTS for aged samples which is attributed to heat, seawater contamination, and oil. The highest and lowest HTS values recorded are 402.9 MPa and 118.3 MPa for unaged and tap water with oil-aged samples respectively. HTS in aged samples is compared with unaged samples. The study opens up avenues in identifying the best-suitable combination for retaining HTS under various aging conditions.

Pipe Inspection Robot

Abstract: A pipe inspection robot is device that is inserted into pipes to check for obstruction or damage. These robots are traditionally manufactured offshore, are extremely expensive, and are often not adequately supported in the event or malfunction. This had resulted in associated environmental services limited. A New Zealand utilize of this equipment, facing significant periods of down time as they wait for their robots to be the repaired. Recently, they were informing that several robots were no longer supported. This project was conceived to redesign the electronics control systems one of these PIR, utilizing the existing mechanical platform. Requirements for the robot were that it must operate reliably in confined, dark and wet environments and provides a human wear with a digital video feed of the internal status of the pipes. There robot should as much as possible incorporate off the shaft components, cheap, and potentially onsite repair. This project details the redesign and constructions of such robots. Its employees their electronic boards integrated with mechanical components and provides video feedback via custom graphical interface although at the prototypes state the electronics has been successful with cost of less than a length of the original robot purchase prize

Synergistic enhancement of hydrophobic dental adhesives: autonomous strengthening, polymerization kinetics, and hydrolytic resistance

The leading cause of composite restoration failure is recurrent marginal decay. The margin between the composite and tooth is initially sealed by a low-viscosity adhesive, but chemical, physical, and mechanical stresses work synergistically and simultaneously to degrade the adhesive, destroying the interfacial seal and providing an ideal environment for bacteria to proliferate. Our group has been developing self-strengthening adhesives with improved chemical and mechanical characteristics. This paper reports a self-strengthening adhesive formulation that resists hydrolysis-mediated degradation by providing intrinsic reinforcement of the polymer network through synergistic stimulation of free-radical polymerization, sol-gel reaction, and hydrophobicity. Hydrophobic resin formulation (NE1) was developed using HEMA/BisGMA 28/55w/w and 15 wt% MPS. Control (NC1) contained HEMA/BisGMA 28/55 w/w and 15 wt% MES. The polymerization kinetics, water sorption, leachates, and dynamic mechanical properties of the resin samples were investigated. The NC1 and NE1 samples showed comparable polymerization kinetics, degrees of conversion and water sorption. In contrast, NC1 showed significantly higher levels of HEMA and BisGMA leachate, indicating faster degradation in ethanol. At day 3, cumulative HEMA leachate for NC1 was ten times greater than NE1 (p < 0.05). Dynamic mechanical properties were measured at 37 and 70°C in both dry and wet conditions. Under dry conditions, the storage moduli of NC1 and NE1 were comparable and the glass transition temperature (Tg) of NC1 was statistically significantly lower (p < 0.001) than NE1. Under wet conditions, the storage modulus of NC1 was lower than NE1 and at 70°C there was a threefold difference in storage modulus. At this temperature and under wet conditions, the storage modulus of NC1 is statistically significantly lower (p < 0.001) than NE1. The results indicated that in the wet environment, NE1 provided lower chain mobility, higher crosslink density, and more hydrogen bonds. The newly formulated methacrylate-based adhesive capitalizes on free-radical polymerization, sol-gel reactions, and hydrophobicity to provide enhanced mechanical properties at elevated temperatures in wet environments and hydrolytic stability under aggressive aging conditions.

Wet oxidation of TiZrHfNbTaV high-entropy alloys: Role of grain-boundary and interdendritic diffusion

Refractory high-entropy alloys (RHEAs) are sensitive to thermal oxidation, significantly restricting their service performance and potential applications. However, the wet oxidation behavior of RHEAs has remained poorly understood despite the potential risk of catastrophic oxidation caused by water vapor. In this study, the oxidation mechanism of an equiatomic TiZrHfNbTaV high-entropy alloy (HEA) has been investigated in a wet atmosphere at elevated temperatures. Synchronous oxidation of all elements occurs at temperatures below 800 °C. At temperatures above 800 °C, preferential oxidation of Nb, Ti, and Zr, and internal oxidation of V occur on HEAs, which are thermodynamically less preferred as compared with oxidations of more reactive Hf and Ta. Experimental and theoretical analyses show that the oxide grain boundaries and substrate interdendritic regions of HEAs act as diffusion pathways for V and oxidizing species during preferential and internal oxidation processes. This work provides a fundamental understanding of the oxidation of multicomponent alloys in wet environments, which is helpful in the development of effective oxidation resistance strategies and innovative surface engineering techniques.

Research on the influence of solar radiation fuzzy adaptive system on the wet and hot environment in greenhouse

Chinese solar greenhouse (CSG) is an artificially constructed agricultural facility that provides a suitable environment for crop growth. However, the imbalanced temperature and humidity phenomenon occurring in greenhouse during summer greatly affects crop yield. This article proposes the application of solar radiation fuzzy adaptive system in greenhouse to address this issue. The design process includes hardware and algorithm design. The hardware part involves designing the travel distance of the curtain machine and the film winding machine, laying out the temperature and humidity sensors, and designing the control cabinet. The algorithm is optimized based on fuzzy control theory, data acquisition module consists of temperature and humidity sensors, executive components include the curtain machine and the film winding machine, and the data transmission, storage and feedback module consists of the control cabinet and the cloud-based database. These form an adaptive system, which will be subjected to a 10-day comparative experiment. The experimental results showed that in region 3, the peak value of temperature reduction in the third layer during the daytime was 26.2 °C, and the humidity increased by a maximum of 31.5 %. In region 2, the temperature increased by a maximum of 4.2 °C during the nighttime in the second layer, and the humidity decreased by 4.1 °C. Introduction of adaptive systems can play an important role in maintaining microclimate temperature and humidity in summer.

CNN-BiLSTM: A Novel Deep Learning Model for Near-Real-Time Daily Wildfire Spread Prediction

Wildfires significantly threaten ecosystems and human lives, necessitating effective prediction models for the management of this destructive phenomenon. This study integrates Convolutional Neural Network (CNN) and Bidirectional Long Short-Term Memory (BiLSTM) modules to develop a novel deep learning model called CNN-BiLSTM for near-real-time wildfire spread prediction to capture spatial and temporal patterns. This study uses the Visible Infrared Imaging Radiometer Suite (VIIRS) active fire product and a wide range of environmental variables, including topography, land cover, temperature, NDVI, wind informaiton, precipitation, soil moisture, and runoff to train the CNN-BiLSTM model. A comprehensive exploration of parameter configurations and settings was conducted to optimize the model’s performance. The evaluation results and their comparison with benchmark models, such as a Long Short-Term Memory (LSTM) and CNN-LSTM models, demonstrate the effectiveness of the CNN-BiLSTM model with IoU of F1 Score of 0.58 and 0.73 for validation and training sets, respectively. This innovative approach offers a promising avenue for enhancing wildfire management efforts through its capacity for near-real-time prediction, marking a significant step forward in mitigating the impact of wildfires.

Effect of microstructure and micromechanics on wear/wear-corrosion mechanism of laser-repaired Ni-WC coating

Repairing drilling tools with laser cladding technology becomes a meaningful way to reduce costs and increase efficiency. The relationship between the wear/wear corrosion mechanism and micromechanics of laser-repaired Ni-WC coating was investigated. It is found that the received Ni-WC coating is mainly composed of γ-Ni, WC, W2C, and a small amount of CrC and MoC. In dry environment, the surface fatigue crack gradually propagates and develops along the surface as the load increases, forming a peeling phenomenon on the surface. Conversely, the water film was formed as lubrication to reducing the formation of peeling in wet environment. It is found that the wear and damage of the laser-repaired Ni-WC coating in wet environment is lower than that in dry environment. The effect of water film and water cooling on wear of the laser-repaired Ni-WC coating is higher than that of corrosion. In addition, a thin oxide interfacial layer is found under dry sliding at the boundary of WC particle with the maximum width of about 3 μm, leading to low microhardness (H) / elastic modulus (E) of the oxide interfacial layer, which weakens the wear resistance of WC particles in laser-repaired Ni-WC coating.

Self-healing of macroscopic cracks in concrete by cellulose fiber carried microbes

This research introduces a new approach to healing millimeter scale cracks in concrete using Lysinibaccilus Sphaericus Bacteria (LSB) encapsulated in cellulose fibers. Cracking in concrete, particularly macroscopic cracking, can cause premature structural failure and reduce its lifespan, which is a critical industry challenge. While bacteria encapsulated in cellulose fibers have been used to heal cement mortar, the studies are limited to heal much narrower cracks. In this study, we integrate LSB, known for its strong biocalcification abilities, with the protective environment of cellulose fibers, which are renewable and sustainable, for healing millimeter scale cracks in ordinary cement concrete. To understand the healing process, we firstly used a 3D-printed polymeric scaffold for preliminary observations of calcite precipitation, demonstrating the potential of bacteria-induced calcification in a controlled environment before applying these insights to concrete. We then studied the self-healing of concrete. Through mechanical testing, we identified the optimal concentration of cellulose fiber as 0.45 % by volume of mortar. Approximately 2.38 × 108 bacteria were immobilized in each gram of cellulose fibers. With cellulose fiber encapsulated LSB, the test results show up to 25 % increase in compressive strength and split tensile strength. After crack healing, the self-healing concrete still has higher mechanical strength than the undamaged control concrete. Particularly, the self-healing concrete was able to heal cracks up to 2.5 mm wide in fully wet environments and 1.5 mm wide in wet-dry conditions. This research also highlights the resilience of bacteria carried by cellulose fibers against harsh environmental conditions, including high temperatures at 160 °C, ensuring the durability and applicability of the proposed self-healing concrete in diverse climates. Integrating cellulose fibers encapsulated LSB into concrete represents a significant breakthrough in addressing the perennial problem of concrete cracking, offering a promising avenue for constructing durable and maintenance-free structures.

Microcell and macrocell corrosion kinetics of steel bars in reinforced concrete slabs subjected to alternate wet and dry environments

Electrochemical kinetics of steel bar corrosion in concrete is of complex nature, especially when it is subjected to alternate wet and dry environments with changes in conditions of steel-concrete interface and rust properties. In this paper, a quantitative electrochemical mechanism was proposed based on thermodynamics and anodic polarisation kinetics to account for variations of microcell and macrocell current densities in reinforced concrete (RC) slabs subjected to periodic wetting and drying cycles. Effects of environmental conditions on corrosion process were incorporated into anodic Tafel slope through three quantifiable parameters, namely, corrosion potential, linear polarisation resistance and ferrous ion concentration at the steel bar surface. A numerical model was established based on the proposed mechanism to quantify microcell and macrocell current densities. An experimental programme of two RC slabs with multiple steel bars arranged at different layers was conducted to verify the numerical model. It shows that the model could reasonably predict variations of both microcell and macrocell corrosion under different wet and dry environments. When concrete was moistened, current density was substantially increased compared to that in dry concrete. Macrocell contribution from uncorroded steel bars at different layers was more significant than microcell corrosion on the corroded bar itself, especially in wet environments.

Study on the influence mechanism of hydrophobic materials-MPTMS and DMDMOS on the water resistance performance of asphalt mixtures

The interfacial adhesion between aggregate and asphalt is a critical factor affecting the water damage resistance performance of asphalt mixtures. To enhance the adhesion between aggregate and asphalt, Methyltrimethoxysilane (MPTMS) and Dimethyldimethoxysilane (DMDMOS) were co-opted to modify the aggregate surface. The interfacial strength between aggregate and asphalt was analyzed by water boiling test and contact angle experiment, and the mechanism of aggregate interfacial modification was investigated by combining SEM, FTIR and MD. The results showed that: hydrophobic treatment of aggregates reduces the water absorption rate of aggregates in a wet environment and significantly improves the water damage resistance of asphalt mixtures; MPTMS and DMDMOS reduced the aggregate surface polarity component, thus improving the match between aggregate and asphalt; The optimal processing environment for aggregates is acidity and 30 minutes. Further mechanistic tests and simulations showed that the reactive Si-O portion of the polymer reacts with the Si-O-C portion of MPTMS and DMDMOS to form hydrophobic clusters on the surface of the polymer, increasing the aggregate surface roughness. The clusters attract asphalt molecules to arrange closely and orderly around them. The intramolecular interactions and molecular angular energy of asphalt molecules are significantly reduced, which improves the stability of the aggregate-asphalt system, and further enhances the bonding energy between the aggregate and the asphalt, thus improving the water damage resistance of asphalt mixtures.

A facile one step route that introduces functionality to polymer powders for laser sintering

Laser Sintering (LS) is a type of Additive Manufacturing (AM) exploiting laser processing of polymeric particles to produce 3D objects. Because of its ease of processability and thermo-physical properties, polyamide-12 (PA-12) represents ~95% of the polymeric materials used in LS. This constrains the functionality of the items produced, including limited available colours. Moreover, PA-12 objects tend to biofoul in wet environments. Therefore, a key challenge is to develop an inexpensive route to introduce desirable functionality to PA-12. We report a facile, clean, and scalable approach to modification of PA-12, exploiting supercritical carbon dioxide (scCO2) and free radical polymerizations to yield functionalised PA-12 materials. These can be easily printed using commercial apparatus. We demonstrate the potential by creating coloured PA-12 materials and show that the same approach can be utilized to create anti-biofouling objects. Our approach to functionalise materials could open significant new applications for AM.