Robustα-Fe_(2)O_(3)/Epoxy Resin Superhydrophobic Coatings for Anti-icing Property

α-Fe_(2)O_(3)/epoxy resin composite superhydrophobic coating was prepared withα-Fe_(2)O_(3) nanoparticles and epoxy resin by spin coating method.The coating without epoxy resin has higher contact angle(CA)and lower ice adhesion strength(IAS),but the mechanical properties are poor.Theα-Fe_(2)O_(3)/epoxy resin composite superhydrophobic coating exhibits good mechanical durability.In addition,compared with the bare aluminum substrate,the Ecorr of the composite coating is positive and the Jcorr is lower.The inhibition efficiency of the composite coating is as high as 99.98%in 3.5 wt%NaCl solution.The difference in the microstructure caused by the two preparation methods leads to the changes in mechanical properties and corrosion resistance of composite superhydrophobic coating.

Study of Flow and Heat Transfer in an Ejector-Driven Swirl Anti-Icing Chamber

The formation of ice on the leading edge of aircraft engines is a serious issue,as it can have catastrophic consequences.The Swirl Anti-Icing(SAI)system,driven by ejection,circulates hot fluid within a 360°annular chamber to heat the engine inlet lip surface and prevent icing.This study employs a validated Computational Fluid Dynamics(CFD)approach to study the impact of key geometric parameters of this system on flow and heat transfer characteristics within the anti-icing chamber.Additionally,the entropy generation rate and exergy efficiency are analyzed to assess the energy utilization in the system.The research findings indicate that,within the considered flow range,reducing the nozzle specific areaφfrom 0.03061 to 0.01083 can enhance the ejection coefficient by over 60.7%.This enhancement increases the air circulating rate,thereby intensifying convective heat transfer within the SAI chamber.However,the reduction inφalso leads to a significant increase in the required bleed air pressure and a higher entropy generation rate,indicating lower exergy efficiency.The nozzle angleθnotably affects the distribution of hot and cold spots on the lip surface of the SAI chamber.Increasingθfrom 0°to 20°reduces the maximum temperature difference on the anti-icing chamber surface by 60 K.

State of the art and practice of pavement anti-icing and de-icing techniques

Pavement snow and icing are worldwide problems, but effective countermeasures are just beginning to be developed in China. The two most common snow and ice removal methods are mechanical clearance and chemical melting, and the advantages and disadvantages of each approach are discussed here, including environmental and structural damage caused by corrosive snow melting agents. New developments in chemical melting agents and mechanical equipment are discussed, and an overview of alternative thermal melting systems is presented, including the use of geothermy and non-geothermal heating systems utilizing solar energy, electricity, conductive pavement materials, and infrared/microwave applications. Strategic recommendations are made for continued enhancement of public safety in snow and ice conditions.

Fast Algorithm for Prediction of Airfoil Anti-icing Heat Load

Many flight and icing conditions should be considered in order to design an efficient ice protection system to prevent ice accretion on the aircraft surface. The anti-icing heat load is the basic knowledge for the design of a thermal anti-icing system. In order to help the design of the thermal anti-icing system and save the design time, a fast and efficiency method for prediction the anti-icing heat load is investigated. The computation fluid dynamics (CFD) solver and the Messinger model are applied to obtain the snapshots. Examples for the calculation of the anti-icing heat load using the proper orthogonal decomposition (POD) method are presented and compared with the CFD simulation results. It is shown that the heat loads predicted by POD method are in agreement with the CFD computation results. Moreover, it is obviously to see that the POD method is time-saving and can meet the requirement of real-time prediction.

Anti-Icing Method Based on Reducing Voltage of Transmission Lines

The icing of transmission lines threatens the security of power system. This paper proposes a novel anti-icing method based on reducing voltage of the transmission lines. The line voltage can be reduced by regulating the ratio of the transformers which install the both ends of the transmission lines. The line current can be increased and the power loss of the transmission lines can also be increased, which means the heat generated by power loss increases and the icing process of the transmission lines can be restrained. When the icing may occur in the atrocious weather, the anti-icing transformers installed the both ends of transmission line are put into operation. The ratios of transformers are regulated to the appropriate value. The current of transmission line can be increased to the value that is a little greater than the critical current, which can realize the purpose of anti-icing. At the same time, the conditions of normal running in the load side are kept invariably, which can ensure the security of power system. This method can be applicable to a wide range. It's an effective measure to prevent the icing of the transmission lines.

Super-hydrophobic film deposition by an atmospheric-pressure plasma process and its anti-icing characteristics

In this work,the super-hydrophobic(SH)surface was prepared through chemical vapor deposition process by an argon atmospheric pressure plasma jet source with HMDSN(hexamethyldisilazane)as the polymerization precursor.Plasma synthesized organosilicon(SiOxCyHz)thin films with water contact angle over 160°and sliding angle below 5°,were able to be achieved.FTIR and XPS analysis indicates a large number of hydrocarbon compositions were polymerized in the thin films enduing the latter very-low surface free energy.SEM shows the SH films display micro-nanostructure and with high degree of averaged surface roughness 190 nm evaluated by AFM analysis.From experiments under controlled low-temperature and moisture conditions,the prepared SH surface exhibits good anti-icing effects.Significantly prolonging freezing time was achievable on the SH thin films for both static and sliding water droplets.This investigation demonstrates the anti-icing potentials of SH surface prepared through low-cost simple atmospheric-pressure plasma polymerization process.

Design and Development of Anti-Icing Aluminum Surface

An anti-icing surface has been designed and prepared with an aluminum panel by creating an artificial lotus leaf which is highly hydrophobic. The hydrophobicity of a solid surface can be generated by decreasing its surface tension and increasing the roughness of the surface. On a highly hydrophobic surface, water has a high contact angle and it can easily rolls off, carrying surface dirt and debris with it. Super-cooled water or freezing rain can also run off this highly hydrophobic surface instead of forming ice on the surface, due to the reduction of the liquid-solid adhesion. This property can also help a surface to get rid of the ice after the water becomes frozen. In this study, a Cassie-Baxter rough surface was modeled, and an aluminum panel was physically and chemically modified based on the modeled structure. Good agreement was found between predicted values and experimental results for the contact and roll-off angles of water. Most importantly, by creating this highly hydrophobic aluminum rough surface, the anti-icing and de-icing properties of the modified surface were drastically improved compared to the control aluminum surface, and the cost will be reduced.

An Abrasion Resistant TPU/SH-SiO_(2) Superhydrophobic Coating for Anti-Icing and Anti-Corrosion Applications

As a passive anti-icing strategy,properly designed superhydrophobic coatings can demonstrate outstanding performances.However,common preparation strategies for superhydrophobic coatings often lead to environmental pollution,high energy-consumption,high-cost and other undesirable issues.Besides,the durability of superhydrophobic coating also plagues its commercial application.In this paper,we introduced a facile and environment-friendly technique for fabricating abrasion-resistant superhydrophobic surfaces using thermoplastic polyurethane(TPU)and modified SiO_(2)particles(SH-SiO_(2)).Both materials are non-toxicity,low-cost,and commercial available.Our methodology has the following advantages:use of minimal amounts of formulation,take the most streamlined technical route,and no waste material.These advantages make it attractive for industrial applications,and its usage sustainability can be promised.In this study,the mechanical stability of the superhydrophobic surface was evaluated by linear wear test.It is found that the excellent wear resistance of the superhydrophobic coating benefits from the characteristics of raw materials,the preparation strategy,and the special structure.In anti-icing properties test,the TPU/SH-SiO_(2)coating exhibits the repellency to the cold droplets and the ability to extend the freezing time.The electrochemical corrosion measurement shows that the asprepared superhydrophobic surface has excellent corrosion resistance that can provide effective protection for the bare Q235 substrates.These results indicate that the TPU/SH-SiO_(2)coating possesses good abrasion resistance and has great potential in anti-corrosion and anti-icing applications.

Fabrication of Biomimetic Surface for Hydrophobic and Anti-icing Purposes via the Capillary Force Lithography

In this paper,inspired by lotus leaf surfaces,we fabricated biomimetic multi-scale micro-nano-structures by Two-Step Capillary Force Lithography(TS-CFL)and UV-assisted Capillary Force Lithography(UV-CFL).The experimental results indicated that TS-CFL was unfitted to fabricate large-area multi-scale micro-nano-structures.Conversely,UV-CFL can fabricate large-area multi-scale micro-nano-structures.We discussed the hydrophobic and anti-icing properties of the biomimetic surfaces fabricated by these two technologies.We found that small structures are significant for improving the hydrophobic anti-icing properties of single-structured or structureless surfaces.We believe that these results can complement the experimental details of both technologies and enable the development of more interesting micro-nano-structures biomimetic surfaces by both technologies in the future.

An anti-icing scaling method for wind tunnel tests of aircraft thermal ice protection system

The efficiency of the aircraft Ice Protection Systems(IPSs)needs to be verified through icing wind tunnel tests.However,the scaling method for testing the IPSs has not been systematically established yet,and further research is needed.In the present study,a scaling method specifically designed for thermal IPSs was derived from the governing equation of thin water film.Five scaling parameters were adopted to address the heat and mass transfer involved in the thermal anti-icing process.For method validation,icing wind tunnel tests were conducted using a jet engine nacelle model equipped with a bleed air IPS.The non-dimensional surface temperature and runback ice closely matched for both the reference and scaled conditions.The validation confirms that the scaling method is capable of achieving the similarity of surface temperature and the runback ice coverage.The anti-icing scaling method can serve as an important supplement to the existing icing similarity theory.

Facile designing a superhydrophobic anti-icing surface applied for reliable long-term deicing

While superhydrophobic coatings have shown promise as potential anti-icing coatings, the surface roughness of these coatings is prone to damage during repeated icing-deicing cycles. Herein, two kinds of superhydrophobic anti-icing coatings are prepared from organic resin and micro-nano particles using two strategies, and their excellent anti-icing properties are also investigated. However, superhydrophobic surface Ⅰ(SF1), prepared by first strategy, cannot be used for extended periods of time due to irreversible damage to the surface roughness during the icing–deicing process. Finite element simulations and experimental studies are preformed to investigate the fatal issue of such roughness damage. In contrast,the anti-icing properties of superhydrophobic surface Ⅱ(SF2), prepared by second strategy, can easily regain through a simple sandpaper abrasion treatment even the surface roughness was damaged during the icing–deicing process. These exploratory results and SF2 preparation strategy provide a facile design of anti-icing coating, and the derived restorable anti-icing coating is expected to be useful for a wide application.

A Super-robust Armoured Superhydrophobic Surface with Excellent Anti-icing Ability

It has been proved that the construction of interconnected armour on superhydrophobic surface could significantly enhance the mechanical robustness.Here,a new kind of armour with frame/protrusion hybrid structure was achieved by nanosecond laser technology.Then,this armoured superhydrophobic surface demonstrated excellent durability,which could withstand linear abrasion(~3 N press)800 cycles,water jet test(1.0 MPa pressure)40 times and 100℃treatment 18 days.Particularly,the armoured superhydrophobic sample shows outstanding anti-icing ability,which can speed up the supercooled water dropping(no adhesion within 2 h),increase the freezing delay time by~3 times and maintain low adhesion force(less than 35 kPa)after 30 icing/de-icing cycles.Further finite element analysis and theoretical modeling proved that the developed frame/protuberance hybrid structure could effectively enhance the durability.The relatively low surface accuracy in this study can significantly reduce processing cost,which provides a bright future for the practical application of armour superhydrophobic materials.

Thermal Feature Analysis of a New Hot-Air Anti-Icing Structure

Ice accretion on surfaces of the aircraft and engine is a serious threat to the flight safety.In this paper,a novel hot air anti-icing method is proposed based on the porous foam.Taking the NACA0012 airfoil as an example,the traditional thermal protection structure is proved to exist the deficiency in balancing the heat exchange caused by route loss of the heat.By dividing the hot chamber into multiple regions to fill with various foam metal,flow resistance characteristics and heat transfer characteristics for this protection mode are analyzed in order to derive the maximized benefit in anti-icing process.The calculation results reveal that,under the same condition,the region filled with foamed copper not only improves the temperature uniformity on the anti-icing area,but also achieves a better protection effect for enhancing heat transfer between the tube and the hot gas,averagely above 20℃higher than it without porous foam filling in surface temperature.Additionally,the minimum mass flow rate of the protection hot air is reduced by 16.7%.The gratifying efficiency of the porous filler in fortifying heat transfer confirms the potential of replacing the efficient but complex heat transfer design with simple structure filled with foam metal.

Neurosyphilis complicated by anti-γ-aminobutyric acid-B receptor encephalitis: A case report

BACKGROUND Syphilis is an infectious disease caused by Treponema pallidum that can invade the central nervous system,causing encephalitis.Few cases of anti-N-methyl-Daspartate receptor autoimmune encephalitis(AE)secondary to neurosyphilis have been reported.We report a neurosyphilis patient with anti-γ-aminobutyric acid-B receptor(GABABR)AE.CASE SUMMARY A young man in his 30s who presented with acute epileptic status was admitted to a local hospital.He was diagnosed with neurosyphilis,according to serum and cerebrospinal fluid(CSF)tests for syphilis.After 14 d of antiepileptic treatment and anti-Treponema pallidum therapy with penicillin,epilepsy was controlled but serious cognitive impairment,behavioral,and serious psychiatric symptoms were observed.He was then transferred to our hospital.The Mini-Mental State Examination(MMSE)crude test results showed only 2 points.Cranial magnetic resonance imaging revealed significant cerebral atrophy and multiple fluidattenuated inversion recovery high signals in the white matter surrounding both lateral ventricles,left amygdala and bilateral thalami.Anti-GABABR antibodies were discovered in CSF(1:3.2)and serum(1:100).The patient was diagnosed with neurosyphilis complicated by anti-GABABR AE,and received methylprednisolone and penicillin.Following treatment,his mental symptoms were alleviated.Cognitive impairment was significantly improved,with a MMSE of 8 points.Serum anti-GABABR antibody titer decreased to 1:32.The patient received methylprednisolone and penicillin after discharge.Three months later,the patient’s condition was stable,but the serum anti-GABABR antibody titer was 1:100.CONCLUSION This patient with neurosyphilis combined with anti-GABABR encephalitis benefited from immunotherapy.

A Passive Anti-icing Strategy Based on a Superhydrophobic Mesh with Extremely Low Ice Adhesion Strength

Although superhydrophobic materials have attracted much research interest in anti-icing,some controversy still exists.In this research,we report a cost-effective method used to verify the contribution of area fraction to ice adhesion strength.We tried to partially-embed siliea nanopnarticles into microscale fabrics of a commercial polyamide mesh.Then,the area fraction could be determined by altering the mesh size.Generally,the ice adhesion strength decreases as the area fraction decreases.An ice adhesion strength of~1.9 kPa and a delayed freezing time of~1048 s can be obtained.We attribute the low ice adhesion strength to the combination of superhydro-phobicity and stress concentration.The superhydrophobicity prohibits the water from penetrating into the voids of the meshes,and the small actual contact area leads to stress concentration which promotes interfacial crack propagation.Moreover,our superhydrophobic mesh simultaneously exhibis a micro-nano hierarchical structure and a partally-cmbedded structure.Therefore,the as-prepared superhydrophobic mesh retained the ieephobicity after 20 icingldeicing cycles,and maintained its superhydrophobicity even afier 60 sandpaper-abrasion cycles and a 220"C thermal treatment.

Rational Fabrication of Superhydrophobic Nanocone Surface for Dynamic Water Repellency and Anti-icing Potential

In this work,a simple and economic route was presented to fabricate an anti-icing superhydrophobic surface with nanocone structures,which were constructed only by one-step facile method of hydrothermal treatment with zinc acetate on the aluminum substrate.After modifying with fluoroalkylsilane (FAS-17),the nanocone structures with the appropriate size could induce the high superhydrophobicity with the water contact angle reaching 160.2° ± 0.4° and the sliding angle only being 1 ° ± 0.5°.Under the dynamic environments,the impact droplets could rapidly bounced off the surface with the shorter contact time of^1 0.6 ms,and it was mainly attributing to lower capillary adhesive force (water adhesion force of 4.1 μN) induced by the open system of nanocone structures.Furthermore,the superhydrophobic nanocone surfaces were verified to be a promising anti-icing/icephobic materials,on which the water droplets needed to spend the time of ~517 s to complete the entire freezing process at-10 ℃,displaying the increased ~50 times of icing-delay performance comparing with untreated substrate.Even if ice finally was formed on the superhydrophobic nanocone surfaces,it could be easily removed away with lower ice adhesion of^45 kPa.The repeatable measurement of ice adhesion strength on the same place of the superhydrophobic surface is still far less than the surface ice adhesion of smooth substrate,exhibiting better stability.

Superior anti-icing strategy by combined sustainable liquid repellence and electro/photo-responsive thermogenesis of oil/MWNT composite

This paper introduces an effective anti-icing strategy that uses passive anti-icing property and active de-icing functions concurrently.These dual capabilities can alleviate the icing problem more effectively than either a passive or active function alone.The developed material is a slippery liquid-repellent elastic conductor(SLEC);it is an organogel that is composed of multi-walled carbon nanotubes,oil,and polydimethylsiloxane.The SLEC maintains passive water-droplet sliding ability even on wet surfaces that frequently occur in cold conditions(e.g.,during condensation and defrosting),suppresses ice nucleation,and shows ice adhesion strength as low as^20 kPa.The SLEC releases heat when it is subject to electrical or photonic stimulation,and can therefore it can prevent ice formation and melt ice that has already formed on a surface.This material has sustainable liquid repellence by syneresis and replenishment;this ability ensures long-lasting anti-icing property,and results in exceptional durability.This durability is stable against mechanical damage.The superior dual anti-icing capabilities together with the sustainable and stable liquid repellence should generate synergistic effects,and yield a powerful anti-icing tool that can broaden the range of icing applications.

Bio-inspired slippery surfaces with multifunctional anti-icing performance

Superior anti-icing and active deicing multifunctional surfaces are highly desired in outdoor infrastructure and work of aircraft,automobiles,wind turbines,power transmission,etc.Herein,inspired by microstructures and functions of natural opal and Nepenthes pitcher plants,we present a novel multifunctional inverse opal slippery anti-icing surface(IOSAS)by employing a combined method of colloidal nanoparticles self-assembly,microstructure mold replication,and hydrophobic lubricating fluid infiltration.Because of the 3D long range ordered nanoscale porous structure of artificial inverse opal,the lubricating liquid could wick into,wet,and stably adhere to IOSAS,forming thousands of solid-liquid interfaces and defect-free and inert slippery surface.Thus,the IOSAS was imparted with inhibiting ice nucleation property and hindering heat transfer and ice crystals’growth characteristics.Owing to the existence of a thin liquid layer on the surface,the mechanical interlock between porous substrate and ice is greatly weakened,which imparts the slippery surface with low ice adhesion strength,and the frozen droplet and ice bulk could be easily removed.In addition,we have demonstrated that the supercooled IOSAS has no adhesion to moving water droplets,while various subcooled metal surfaces are adhesive,and this exhibits liquid-infused inverse opal surfaces dynamic low-temperature water-repellent performance.These characteristics endow IOSAS with multifunctional anti-icing performances,making it a promising option for a wide range of ice-phobic applications.

Self-healing anti-icing coatings prepared from PDMS polyurea

With the help of double hydrogen bonds between urea groups, a self-healing anti-icing coating was prepared from polydimethylsiloxane(PDMS)-based polyurea(PDMSPU) that was synthesized from bis(3-aminopropyl)-terminated PDMS and2,4-toluene diisocyanate. Furthermore, by incorporating a lubricant of inert silicone oil and the cross-linking agent of 1,3,5-tris-(4-aminophenoxy)benzene(TAPOB), the anti-icing coatings exhibited elastic, slippery and durable properties. The wettability,ice shear strength, abrasion-resistance, mechanical and self-healing properties of the prepared anti-icing coatings were systematically investigated. Results showed that the ice shear strength of the PDMSPU anti-icing coating with 150 wt% silicone oil was 7.9±2.9 kPa, significantly lower than that of pristine PDMSPU(74.7±7.2 kPa). The additional introduction of 2 wt%TAPOB could effectively counteract the adverse effect of the lubricant so that the tensile strength(~1 MPa) of the coating could be comparable to pristine PDMSPU(855±96 kPa). The PDMSPU coating containing 150 wt% silicone oil and 2 wt% TAPOB could maintain the ice shear strength below 50 kPa against 10 icing/deicing cycles and at 12.0±3.3 kPa after 5000 abrasion cycles, and exhibit self-healing properties after treating at 60°C for 10 or 15 h. The slippery self-healing PDMSPU anti-icing coatings could be suitable for anti-icing surfaces in low temperature environments.

Bio-inspired manufacturing of superwetting surfaces for fog collection and anti-icing applications

As a century-old concept,superwettability has aroused the interest of researchers in the past decades,attributed to the discoveries of the mechanisms of special wetting phenomena in nature.Bio-inspired manufacturing of superwetting surfaces for fog collection and anti-icing applications has become mainstream research,potentially alleviating the problem of water shortage and ice accidents.Superwetting surfaces for fog collection and anti-icing applications involve a reverse process,in which the former gathers water spontaneously,while the latter repels water.Contrastive analysis of the two is essential for the comprehensive understanding of superhydrophilic/superhydrophobic surfaces and boosting their applications.Herein,wetting theories and basic mechanisms for fog collection and anti-icing are briefly introduced.Then,manufacturing methods of bionic structures and surfaces are systematically reviewed after discussing the typical organisms with superwettability.Finally,conclusions are drawn and prospects for future development are proposed.