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A review of the development of asphalt foaming technology
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作者 Qiang Li Shijie Song +2 位作者 Jiaqing Wang Ning Wang Shuai Zhang 《Journal of Road Engineering》 2024年第3期334-347,共14页
To comprehensively assess the current state-of-art in asphalt foaming technology, the following four key aspectshave been reviewed systematically: foaming principles, test methods, evaluation indicators, and influenci... To comprehensively assess the current state-of-art in asphalt foaming technology, the following four key aspectshave been reviewed systematically: foaming principles, test methods, evaluation indicators, and influencing factors.Key findings reveal that asphalt foaming was primarily driven by the vaporization of water, with deteriorationprocesses including bubble collapse and liquid film drainage. However, the current understanding of asphaltfoaming principles remains limited, primarily due to difficulties in capturing and precisely measuring its microscopic behaviors during asphalt foaming process. Volume changes provided an intuitive means to evaluate theexpansion capacity of asphalt and its foaming stability. Bubble evolution characteristics of foamed asphalt offeredpromising insights into its foaming performance. Traditional ruler and stopwatch-based assessments were beingsuperseded by automated techniques like laser and ultrasonic ranging. Nevertheless, the current measuringequipment still lacks the capability to comprehensively evaluate the foaming effect of asphalt across various dimensions. Asphalt temperature and foaming water consumption significantly affected asphalt foaming performance, and the inclusion of foaming agents typically led to a notable increase in the half life of foamed asphalt.However, the interaction between foaming agents and asphalt, as well as the underlying mechanisms affecting thefoaming effect, are still unclear and require further exploration. Future research should primarily focus on thecorrelation between asphalt foaming effect and mixture performance, aiming to guide the practical engineeringapplication of foamed asphalt mixtures and enlarge the advantages of such low-emission and sustainable mixtures. 展开更多
关键词 foamed asphalt foaming mechanism Test methods Evaluation indicators Influencing factors
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Numerical Simulation of the Mechanical Stirring Process in a Tannin-Based Foaming Precursor Resin
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作者 Lan Huang Wenbin Yuan +2 位作者 Hisham Essawy Xiaojian Zhou Xinyi Chen 《Fluid Dynamics & Materials Processing》 EI 2024年第10期2219-2234,共16页
Tannin foam is a new functional material.It can be widely applied to the automobile industry,construction industry,and packaging industry due to its wide range of raw materials,renewable,easily degraded,low cost and a... Tannin foam is a new functional material.It can be widely applied to the automobile industry,construction industry,and packaging industry due to its wide range of raw materials,renewable,easily degraded,low cost and almost no pollution.Preparing tannin foam is a very complex process that includes high temperature,two phases,mechanical agitation,and phase change.To investigate the influence of the stirring velocity and paddle shape,simulation was calculated by making use of the volume of fluid(VOF)method and multiple reference frame(MRF)method in a three-dimensional flow field of tannin-based foaming precursor resin.The gas holdup and velocity magnitude were analysed with various conditions of mechanical velocities and paddle shape in the stirring flow field.The result shows the higher the velocity,the greater the disturbance and paddle shape between the eggbeater and the Rushton turbine,obviously the paddle shape of the eggbeater with a wider range of agitation,which can entrap more air into the tannin-based foaming precursor resin in a short time.Especially when the speed is 1500 rpm,the flow field of the Rushton turbine comes out of a ditch,which decreases the efficiency of mass transfer;there is less air to mix into the tannin-based foaming precursor resin,which causes unevenness.At the same time,the eggbeater shows the marvelous capability of hybrid as it has two vortexes and multiple cycles that make a difference from the Rushton turbine,which has only one vortex and two upper and lower loops;the structure makes the flow field more stable allowed evenness of flow field tannin-based foaming precursor resin.The results reveal that it is beneficial for tannin-based foaming precursor resin to use an eggbeater with a speed of 1500 rpm to reduce the consumption of resources while obtaining a uniform flow field. 展开更多
关键词 Tannin-based foaming precursor resin mechanical agitation numerical simulation volume of fluid(VOF) multiple reference frame(MRF)
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Endoscopic polidocanol foam sclerobanding for the treatment of grade Ⅱ-Ⅲ internal hemorrhoids:A prospective,multi-center,randomized study 被引量:3
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作者 Chun-Ying Qu Fei-Yu Zhang +10 位作者 Yi Zhang Ming-Ming Li Zheng-Hong Li Mei-Hong Cai Lei-Ming Xu Feng Shen Wen Wang Wu-Lian Lin Feng-Yu Gao Hao Zhang Guang-Yu Chen 《World Journal of Gastroenterology》 SCIE CAS 2024年第27期3326-3335,共10页
BACKGROUND Endoscopic rubber band ligation(ERBL)is a nonsurgical technique for the treatment of symptomatic internal hemorrhoids but is limited by recurrence and post-procedural pain.AIM To evaluate satisfaction,long-... BACKGROUND Endoscopic rubber band ligation(ERBL)is a nonsurgical technique for the treatment of symptomatic internal hemorrhoids but is limited by recurrence and post-procedural pain.AIM To evaluate satisfaction,long-term recurrence,and post-procedural pain in managing internal hemorrhoids using a combination of polidocanol foam sclerotherapy and ERBL.METHODS This was a prospective,multicenter,randomized study.A total of 195 consecutive patients diagnosed with grade II-III internal hemorrhoids were enrolled from four tertiary hospitals and randomly divided into a cap-assisted endoscopic polidocanol foam sclerobanding(EFSB)or an ERBL group.All patients were followed-up for 12 months.Symptom-based severity and post-procedural pain were assessed using a hemorrhoid severity score(HSS)and a visual analog scale(VAS).Continuous variables were reported as medians and interquartile range.RESULTS One hundred and ninety-five patients were enrolled,with 98 in the EFSB group.HSS was lower in the EFSB group than in the ERBL group at 8 weeks[4.0(3.0-5.0)vs 5.0(4.0-6.0),P=0.003]and 12-month[2.0(1.0-3.0)vs 3.0(2.0-3.0),P<0.001]of follow-up.The prolapse recurrence rate was lower in the EFSB group at 12 months(11.2%vs 21.6%,P=0.038).Multiple linear regression analysis demonstrated that EFSB treatment[B=-0.915,95%confidence interval(CI):−1.301 to−0.530,P=0.001]and rubber band number(B=0.843,95%CI:0.595-1.092,P<0.001)were negatively and independently associated with the VAS score 24 hours post-procedure.The median VAS was lower in the EFSB group than in the ERBL[2.0(1.0-3.0)vs 3.0(2.0-4.0),P<0.001].CONCLUSION Cap-assisted EFSB provided long-term satisfaction and effective relief from the recurrence of prolapse and pain 24 hours post-procedure. 展开更多
关键词 Internal hemorrhoids Endoscopic therapy Polidocanol foam SCLEROTHERAPY Rubber band ligation Sclerobanding
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Layered Structural PBAT Composite Foams for Efficient Electromagnetic Interference Shielding 被引量:2
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作者 Jianming Yang Hu Wang +2 位作者 Yali Zhang Hexin Zhang Junwei Gu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第2期273-286,共14页
The utilization of eco-friendly,lightweight,high-efficiency and high-absorbing electromagnetic interference(EMI)shielding composites is imperative in light of the worldwide promotion of sustainable manufacturing.In th... The utilization of eco-friendly,lightweight,high-efficiency and high-absorbing electromagnetic interference(EMI)shielding composites is imperative in light of the worldwide promotion of sustainable manufacturing.In this work,magnetic poly(butyleneadipate-coterephthalate)(PBAT)microspheres were firstly synthesized via phase separation method,then PBAT composite foams with layered structure was constructed through the supercritical carbon dioxide foaming and scraping techniques.The merits of integrating ferroferric oxideloaded multi-walled carbon nanotubes(Fe3O4@MWCNTs)nanoparticles,a microcellular framework,and a highly conductive silver layer have been judiciously orchestrated within this distinctive layered configuration.Microwaves are consumed throughout the process of“absorption-reflection-reabsorption”as much as possible,which greatly declines the secondary radiation pollution.The biodegradable PBAT composite foams achieved an EMI shielding effectiveness of up to 68 dB and an absorptivity of 77%,and authenticated favorable stabilization after the tape adhesion experiment. 展开更多
关键词 Electromagnetic interference shielding Layered structure Supercritical carbon dioxide foaming Poly(butyleneadipateco-terephthalate) MICROCELLULAR
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Lightweight Dual‑Functional Segregated Nanocomposite Foams for Integrated Infrared Stealth and Absorption‑Dominant Electromagnetic Interference Shielding 被引量:1
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作者 Zhonglei Ma Ruochu Jiang +8 位作者 Jiayao Jing Songlei Kang Li Ma Kefan Zhang Junxian Li Yu Zhang Jianbin Qin Shuhuan Yun Guangcheng Zhang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第11期38-55,共18页
Lightweight infrared stealth and absorption-dominant electromagnetic interference(EMI)shielding materials are highly desirable in areas of aerospace,weapons,military and wearable electronics.Herein,lightweight and hig... Lightweight infrared stealth and absorption-dominant electromagnetic interference(EMI)shielding materials are highly desirable in areas of aerospace,weapons,military and wearable electronics.Herein,lightweight and high-efficiency dual-functional segregated nanocomposite foams with microcellular structures are developed for integrated infrared stealth and absorption-dominant EMI shielding via the efficient and scalable supercritical CO_(2)(SC-CO_(2))foaming combined with hydrogen bonding assembly and compression molding strategy.The obtained lightweight segregated nanocomposite foams exhibit superior infrared stealth performances benefitting from the synergistic effect of highly effective thermal insulation and low infrared emissivity,and outstanding absorption-dominant EMI shielding performances attributed to the synchronous construction of microcellular structures and segregated structures.Particularly,the segregated nanocomposite foams present a large radiation temperature reduction of 70.2℃ at the object temperature of 100℃,and a significantly improved EM wave absorptivity/reflectivity(A/R)ratio of 2.15 at an ultralow Ti_(3)C_(2)T_(x) content of 1.7 vol%.Moreover,the segregated nanocomposite foams exhibit outstanding working reliability and stability upon dynamic compression cycles.The results demonstrate that the lightweight and high-efficiency dual-functional segregated nanocomposite foams have excellent potentials for infrared stealth and absorption-dominant EMI shielding applications in aerospace,weapons,military and wearable electronics. 展开更多
关键词 Segregated nanocomposite foams Microcellular structures Infrared stealth EMI shielding Low infrared emissivity
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Electrokinetic-mechanism of water and furfural oxidation on pulsed laser-interlaced Cu_(2)O and CoO on nickel foam 被引量:1
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作者 Yewon Oh Jayaraman Theerthagiri +3 位作者 M.L.Aruna Kumari Ahreum Min Cheol Joo Moon Myong Yong Choi 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第4期145-154,共10页
The electrocatalytic oxidation of biomass-derived furfural(FF)feedstocks into 2-furoic acid(FA)holds immense industrial potential in optics,cosmetics,polymers,and food.Herein,we fabricated Co O/Ni O/nickel foam(NF)and... The electrocatalytic oxidation of biomass-derived furfural(FF)feedstocks into 2-furoic acid(FA)holds immense industrial potential in optics,cosmetics,polymers,and food.Herein,we fabricated Co O/Ni O/nickel foam(NF)and Cu_(2)O/Ni O/NF electrodes via in situ pulsed laser irradiation in liquids(PLIL)for the bifunctional electrocatalysis of oxygen evolution reaction(OER)and furfural oxidation reaction(FOR),respectively.Simultaneous oxidation of NF surface to NiO and deposition of CoO and/or Cu_(2)O on NF during PLIL offer distinct advantages for enhancing both the OER and FOR.CoO/NiO/NF electrocatalyst provides a consistently low overpotential of~359 m V(OER)at 10 m A/cm^(2),achieving the maximum FA yield(~16.37 m M)with 61.5%selectivity,79.5%carbon balance,and a remarkable Faradaic efficiency of~90.1%during 2 h of FOR at 1.43 V(vs.reversible hydrogen electrode).Mechanistic pathway via in situ electrochemical-Raman spectroscopy on CoO/NiO/NF reveals the involvement of phase transition intermediates(NiOOH and CoOOH)as surface-active centers during electrochemical oxidation.The carbonyl carbon in FF is attacked by hydroxyl groups to form unstable hydrates that subsequently undergo further oxidation to yield FA products.This method holds promise for large-scale applications,enabling simultaneous production of renewable building materials and fuel. 展开更多
关键词 Pulsed laser irradiation in liquids Water and furfural oxidation In situ Raman spectroscopy CoO/NiO/nickel foam Cu_(2)O/Nio/nickel foam 2-furoic acid
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Mixed‑Dimensional Assembly Strategy to Construct Reduced Graphene Oxide/Carbon Foams Heterostructures for Microwave Absorption,Anti‑Corrosion and Thermal Insulation 被引量:2
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作者 Beibei Zhan Yunpeng Qu +8 位作者 Xiaosi Qi Junfei Ding Jiao‑jing Shao Xiu Gong Jing‑Liang Yang Yanli Chen Qiong Peng Wei Zhong Hualiang Lv 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第11期1-18,共18页
Considering the serious electromagnetic wave(EMW)pollution problems and complex application condition,there is a pressing need to amalgamate multiple functionalities within a single substance.However,the effective int... Considering the serious electromagnetic wave(EMW)pollution problems and complex application condition,there is a pressing need to amalgamate multiple functionalities within a single substance.However,the effective integration of diverse functions into designed EMW absorption materials still faces the huge challenges.Herein,reduced graphene oxide/carbon foams(RGO/CFs)with two-dimensional/three-dimensional(2D/3D)van der Waals(vdWs)heterostructures were meticulously engineered and synthesized utilizing an efficient methodology involving freeze-drying,immersing absorption,secondary freeze-drying,followed by carbonization treatment.Thanks to their excellent linkage effect of amplified dielectric loss and optimized impedance matching,the designed 2D/3D RGO/CFs vdWs heterostructures demonstrated commendable EMW absorption performances,achieving a broad absorption bandwidth of 6.2 GHz and a reflection loss of-50.58 dB with the low matching thicknesses.Furthermore,the obtained 2D/3D RGO/CFs vdWs heterostructures also displayed the significant radar stealth properties,good corrosion resistance performances as well as outstanding thermal insulation capabilities,displaying the great potential in complex and variable environments.Accordingly,this work not only demonstrated a straightforward method for fabricating 2D/3D vdWs heterostructures,but also outlined a powerful mixeddimensional assembly strategy for engineering multifunctional foams for electromagnetic protection,aerospace and other complex conditions. 展开更多
关键词 Multifunctionality Reduced graphene oxide/carbon foams 2D/3D van der Waals heterostructures Electromagnetic wave absorption Thermal insulation
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Liquid injectivity in a SAG foam process:Effect of permeability
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作者 Jia-Kun Gong Yuan Wang +4 位作者 Ridhwan-Zhafri B.Kamarul Bahrim Raj-Deo Tewari Mohammad-Iqbal Mahamad Amir Rouhi Farajzadeh William Rossen 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期302-314,共13页
Foam is utilized in enhanced oil recovery and CO_(2) sequestration.Surfactant-alternating-gas(SAG)is a preferred approach for placing foam into reservoirs,due to it enhances gas injection and minimizes corrosion in fa... Foam is utilized in enhanced oil recovery and CO_(2) sequestration.Surfactant-alternating-gas(SAG)is a preferred approach for placing foam into reservoirs,due to it enhances gas injection and minimizes corrosion in facilities.Our previous studies with similar permeability cores show that during SAG injection,several banks occupy the area near the well where fluid exhibits distinct behaviour.However,underground reservoirs are heterogeneous,often layered.It is crucial to understand the effect of permeability on fluid behaviour and injectivity in a SAG process.In this work,coreflood experiments are conducted in cores with permeabilities ranging from 16 to 2300 mD.We observe the same sequence of banks in cores with different permeabilities.However,the speed at which banks propagate and their overall mobility can vary depending on permeability.At higher permeabilities,the gas-dissolution bank and the forced-imbibition bank progress more rapidly during liquid injection.The total mobilities of both banks decrease with permeability.By utilizing a bank-propagation model,we scale up our experimental findings and compare them to results obtained using the Peaceman equation.Our findings reveal that the liquid injectivity in a SAG foam process is misestimated by conventional simulators based on the Peaceman equation.The lower the formation permeability,the greater the error. 展开更多
关键词 foam Enhanced oil recovery Surfactant-alternating-gas INJECTIVITY PERMEABILITY
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Semi-quantitative analysis of the structural evolution of mesophase pitch-based carbon foams by Raman and FTIR spectroscopy
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作者 LIU Yue CHANG Sheng-kai +3 位作者 SU Zhan-peng HUANG Zu-jian QIN Ji YANG Jian-xiao 《新型炭材料(中英文)》 SCIE EI CAS CSCD 北大核心 2024年第4期668-680,共13页
Graphitized carbon foams(GFms)were prepared using mesophase pitch(MP)as a raw material by foaming(450℃),pre-oxidation(320℃),carbonization(1000℃)and graphitization(2800℃).The differences in structure and properties... Graphitized carbon foams(GFms)were prepared using mesophase pitch(MP)as a raw material by foaming(450℃),pre-oxidation(320℃),carbonization(1000℃)and graphitization(2800℃).The differences in structure and properties of GFms prepared from different MP precursors pretreated by ball milling or liquid phase extraction were investigated and compared,and semi-quantitative calculations were conducted on the Raman and FTIR spectra of samples at each preparation stage.Semi-quantitat-ive spectroscopic analysis provided detailed information on the structure and chemical composition changes of the MP and GFm de-rived from it.Combined with microscopic observations,the change from precursor to GFm was analyzed.The results showed that ball milling concentrated the distribution of aromatic molecules in the pitch,which contributed to uniform foaming to give a GFm with a uniform pore distribution and good properties.Liquid phase extraction helped remove light components while retaining large aromatics to form graphitic planes with the largest average size during post-treatment to produce a GFm with the highest degree of graphitization and the fewest open pores,giving the best compression resistance(2.47 MPa),the highest thermal conductivity(64.47 W/(m·K))and the lowest electrical resistance(13.02μΩ·m).Characterization combining semi-quantitative spectroscopic ana-lysis with microscopic observations allowed us to control the preparation of the MP-derived GFms. 展开更多
关键词 Mesophase pitch Carbon foams RAMAN FTIR GRAPHITIZATION
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Propagation Properties of Shock Waves in Polyurethane Foam based on Atomistic Simulations
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作者 Zhiqiang Hu Jianli Shao +2 位作者 Shiyu Jia Weidong Song Cheng Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期117-129,共13页
Porous materials are widely used in the field of protection because of their excellent energy absorption characteristics.In this work,a series of polyurethane microscopic models are established and the effect of poros... Porous materials are widely used in the field of protection because of their excellent energy absorption characteristics.In this work,a series of polyurethane microscopic models are established and the effect of porosity on the shock waves is studied with classical molecular dynamics simulations.Firstly,shock Hugoniot relations for different porosities are obtained,which compare well with the experimental data.The pores collapse and form local stress wave,which results in the complex multi-wave structure of the shock wave.The microstructure analysis shows that the local stress increases and the local velocity decreases gradually during the process of pore collapse to complete compaction.Finally,it leads to stress relaxation and velocity homogenization.The shock stress peaks can be fitted with two exponential functions,and the amplitude of attenuation coefficient decreases with the increase of density.Besides,the pore collapse under shock or non-shock are discussed by the entropy increase rate of the system.The energy is dissipated mainly through the multiple interactions of the waves under shock.The energy is dissipated mainly by the friction between atoms under non-shock. 展开更多
关键词 Polyurethane foam Shock wave ATTENUATION Atomistic simulation
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An efficient and mild recycling of waste melamine formaldehyde foams by alkaline hydrolysis
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作者 Shaodi Wu Ning Zhang +7 位作者 Chizhou Wang Xianglin Hou Jie Zhao Shiyu Jia Jiancheng Zhao Xiaojing Cui Haibo Jin Tiansheng Deng 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第5期919-926,共8页
Melamine formaldehyde foam(MFF)generates many poisonous chemicals through the traditional recycling methods for organic resin wastes.Herein,a high MFF degradation ratio of ca.97 wt.%was achieved under the mild conditi... Melamine formaldehyde foam(MFF)generates many poisonous chemicals through the traditional recycling methods for organic resin wastes.Herein,a high MFF degradation ratio of ca.97 wt.%was achieved under the mild conditions(160℃)in a NaOH–H2O system with ammelide and ammeline as the main degradation products.The alkaline solvent had an obvious corrosion effect for MFF,as indicated by scanning electron microscopy(SEM).The reaction process and products distribution were studied by Fourier-transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),and ^(13)C nuclear magnetic resonance(NMR).Besides,the MFF degradation products that have the similar chemical structures and bonding performances to those of melamine can be directly used as the raw material for synthesis of melamine urea-formaldehyde resins(MUFs).Moreover,the degradation system demonstrated here showed the high degradation efficiency after reusing for 7 times.The degradation process generated few harmful pollutants and no pre-or post-treatments were required,which proves its feasibility in the safe removal or recovery of waste MFF. 展开更多
关键词 Melamine formaldehyde foam Degradation Alkaline hydrolysis RECYCLING
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Non-dimensional analysis on blast wave propagation in foam concrete:Minimum thickness to avoid stress enhancement
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作者 Ya Yang Xiangzhen Kong Qin Fang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第6期30-46,共17页
Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau stage.However,stress enhancement rather than stress miti... Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau stage.However,stress enhancement rather than stress mitigation may happen when foam concrete is used as sacrificial claddings placed in the path of an incoming blast load.To investigate this interesting phenomenon,a one-dimensional difference model for blast wave propagation in foam concrete is firstly proposed and numerically solved by improving the second-order Godunov method.The difference model and numerical algorithm are validated against experimental results including both the stress mitigation and the stress enhancement.The difference model is then used to numerically analyze the blast wave propagation and deformation of material in which the effects of blast loads,stress-strain relation and length of foam concrete are considered.In particular,the concept of minimum thickness of foam concrete to avoid stress enhancement is proposed.Finally,non-dimensional analysis on the minimum thickness is conducted and an empirical formula is proposed by curve-fitting the numerical data,which can provide a reference for the application of foam concrete in defense engineering. 展开更多
关键词 foam concrete Blast wave propagation Non-dimensional analysis Stress enhancement
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Experimental investigation of the effects of oil asphaltene content on CO_(2) foam stability in the presence of nanoparticles and sodium dodecyl sulfate
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作者 SADEGHI Hossein KHAZ'ALI Ali Reza MOHAMMADI Mohsen 《Petroleum Exploration and Development》 SCIE 2024年第1期239-250,共12页
Foam stability tests were performed using sodium dodecyl sulfate(SDS)surfactant and SiO2 nanoparticles as foaming system at different asphaltene concentrations,and the half-life of CO_(2) foam was measured.The mechani... Foam stability tests were performed using sodium dodecyl sulfate(SDS)surfactant and SiO2 nanoparticles as foaming system at different asphaltene concentrations,and the half-life of CO_(2) foam was measured.The mechanism of foam stability reduction in the presence of asphaltene was analyzed by scanning electron microscope(SEM),UV adsorption spectrophotometric concentration measurement and Zeta potential measurement.When the mass ratio of synthetic oil to foam-formation suspension was 1:9 and the asphaltene mass fraction increased from 0 to 15%,the half-life of SDS-stabilized foams decreased from 751 s to 239 s,and the half-life of SDS/silica-stabilized foams decreased from 912 s to 298 s.When the mass ratio of synthetic oil to foam-formation suspension was 2:8 and the asphaltene mass fraction increased from 0 to 15%,the half-life of SDS-stabilized foams decreased from 526 s to 171 s,and the half-life of SDS/silica-stabilized foams decreased from 660 s to 205 s.In addition,due to asphaltene-SDS/silica interaction in the aqueous phase,the absolute value of Zeta potential decreases,and the surface charges of particles reduce,leading to the reduction of repulsive forces between two interfaces of thin liquid film,which in turn,damages the foam stability. 展开更多
关键词 CO_(2)foam foam stability ASPHALTENE silica nanoparticle sodium dodecyl sulfate(SDS) repulsive forces surface charges Zeta potential
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Boron nitride silicone rubber composite foam with low dielectric and high thermal conductivity
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作者 Shuilai Qiu Hang Wu +1 位作者 Fukai Chu Lei Song 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第4期224-230,共7页
Silicone rubber(SR)is widely used in the field of electronic packaging because of its low dielectric properties.In this work,the porosity of the SR was improved,and the dielectric constant of the SR foam was reduced b... Silicone rubber(SR)is widely used in the field of electronic packaging because of its low dielectric properties.In this work,the porosity of the SR was improved,and the dielectric constant of the SR foam was reduced by adding expanded microspheres(EM).Then,the thermal conductivity of the system was improved by combining the modified boron nitride(f-BN).The results showed that after the f-BN was added,the dielectric constant and dielectric loss were much lower than those of pure SR.Micron-sized modified boron nitride(f-mBN)improved the dielectric and thermal conductivity of the SR foam better than that of nano-sized modified boron nitride(f-nBN),but f-nBN improved the volume resistivity,tensile strength,and thermal stability of the SR better than f-mBN.When the mass ratio of f-mBN and fnBN is 2:1,the thermal conductivity of the SR foam reaches the maximum value of 0.808 W·m^(-1)·K^(-1),which is 6.5 times that before the addition.The heat release rate and fire growth index are the lowest,and the improvement in flame retardancy is mainly attributed to the high thermal stability and physical barrier of f-BN. 展开更多
关键词 foam COMPOSITES Dielectric properties Thermal conductivity Mechanical properties Flame retardant
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Tamping the movement of the laser absorption cutoff position using gold foam hohlraum
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作者 张璐 李丽灵 +14 位作者 林稚伟 董云松 景龙飞 郑建华 况龙钰 黎航 郑金华 张继彦 宋天明 张志宇 赵阳 牛高 杨冬 杨家敏 丁永坤 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第5期56-61,共6页
In indirect-driven laser fusion experiments,the movement of the laser absorption layer will distort the radiation uniformity on the capsule.The gold foam has advantages in symmetry control and lowering wall plasma blo... In indirect-driven laser fusion experiments,the movement of the laser absorption layer will distort the radiation uniformity on the capsule.The gold foam has advantages in symmetry control and lowering wall plasma blowoff when used in an inertial confinement fusion(ICF)hohlraum.This work investigates the motion of the laser absorption cutoff position using lowdensity foam gold walls.It is found that the motion of the laser absorption cutoff position can be significantly mitigated through optimal initial low density,tailored to a specific laser shape.For a short square laser pulse,the laser absorption cutoff position remains almost stationary at an initial density of approximately 0.6 g cm^(-3).For a long-shaped laser pulse,the minimal motion of the laser absorption cutoff position is observed at an initial density of about 0.1 g cm^(-3).This approach allows for the adjustment of the symmetry of the hohlraum radiation source.The insights gained from this study serve as a crucial reference for optimizing the hohlraum wall density. 展开更多
关键词 hohlraum symmetry laser absorption plasma blowoff gold foam
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Experimental investigation on weak shock wave mitigation characteristics of flexible polyurethane foam and polyurea
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作者 Shiyu Jia Cheng Wang +2 位作者 Wenlong Xu Dong Ma Fangfang Qi 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期179-191,共13页
In recent years,explosion shock wave has been considered as a signature injury of the current military conflicts.Although strong shock wave is lethal to the human body,weak shock wave can cause many more lasting conse... In recent years,explosion shock wave has been considered as a signature injury of the current military conflicts.Although strong shock wave is lethal to the human body,weak shock wave can cause many more lasting consequences.To investigate the protection ability and characteristics of flexible materials and structures under weak shock wave loading,the blast wave produced by TNT explosive is loaded on the polyurethane foam with the density of 200.0 kg/m3(F-200)and 400.0 kg/m3(F-400),polyurea with the density of 1100.0 kg/m^(3)(P-1100)and structures composed of the two materials,which are intended for individual protection.Experimental results indicate that the shock wave is attenuated to weak pressure disturbance after interacting with the flexible materials which are not damaged.The shock wave protective capability of single-layer materials is dependent on their thickness,density and microscopic characteristics.The overpressure,maximum pressure rise rate and impulse of transmitted wave decrease exponentially with increase in sample thickness.For the same thickness,F-400 provides better protective capability than F-200 while P-1100 shows the best protective capability among the three materials.In this study,as the materials are not destroyed,F-200 with a thickness more than10.0 mm,F-400 with a thickness more than 4.0 mm,and P-1100 with a thickness more than 1.0 mm can attenuate the overpressure amplitude more than 90.0%.Further,multi-layer flexible composites are designed.Different layer layouts of designed structures and layer thickness of the single-layer materials can affect the protective performance.Within the research range,the structure in which polyurea is placed on the impact side shows the optimal shock wave protective performance,and the thicknesses of polyurea and polyurethane foam are 1.0 mm and 4.0 mm respectively.The overpressure attenuation rate reached maximum value of 93.3%and impulse attenuation capacity of this structure are better than those of single-layer polyurea and polyurethane foam with higher areal density. 展开更多
关键词 Free-field explosion Weak shock wave mitigation POLYUREA Polyurethane foam Multi-layered composites
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Facile identification of fluorosurfactant category in aqueous film-forming foam concentrates via optimized^(19)F NMR
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作者 Peiyao Chen Shuang Zhuang +5 位作者 Weiguang Chen Zhijian Chen Rongzhen Li Fangyu Chen Tingting Jiang Xiaobin Fu 《Magnetic Resonance Letters》 2024年第3期42-51,共10页
Aqueous film-forming foams(AFFFs)are the primary source of toxic perfluoroalkyl and polyfluoroalkyl substances(PFAS)in wastewater.Thus,it is urgent to develop a facile and fast method for identifying fluorosurfactants... Aqueous film-forming foams(AFFFs)are the primary source of toxic perfluoroalkyl and polyfluoroalkyl substances(PFAS)in wastewater.Thus,it is urgent to develop a facile and fast method for identifying fluorosurfactants in commercially available AFFFs.In this work,fluorine nuclear magnetic resonance(^(19)F NMR)spectroscopy was optimized to measure AFFFs directly with the extra addition of 5%D_(2)O as the locking reagent,and high-quality spectra could be acquired within 4 min(0.1%fluorosurfactant content).Recovery experiments demonstrated that the use of different AFFFs had no marked influence on the quantitative analysis of fluorosurfactants.Such method works with low-field NMR spectroscopy(1.4 T)as well.Two-dimensional(2D)^(19)F COSY NMR was used to make signal assignments for different fluorosurfactant derivatives.The optimized ^(19)F NMR could quantify the commercially available fluorosurfactants in different AFFFs,identify them being in either the perfluorooctane sulfonate(PFOS)or fluorotelomer sulfonic acid(FTS)categories,and distinguish the head-group of PFOS and FTS derivatives,which exhibits great potentials in the developments of relevant commercial detections. 展开更多
关键词 Aqueous film-forming foams FLUOROSURFACTANTS 19F NMR Perfluorooctane sulfonate
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Endoscopic polidocanol foam sclerobanding for treatment of internal hemorrhoids:A novel outpatient procedure
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作者 An-Na Mou Yu-Ting Wang 《World Journal of Gastroenterology》 SCIE CAS 2024年第42期4583-4586,共4页
In the study,we comment on the article by Qu et al.Internal hemorrhoids are the most common anorectal disorders worldwide with bleeding,prolapse,and difficulty in defecation.Endoscopic rubber band ligation(ERBL)is a s... In the study,we comment on the article by Qu et al.Internal hemorrhoids are the most common anorectal disorders worldwide with bleeding,prolapse,and difficulty in defecation.Endoscopic rubber band ligation(ERBL)is a safe,convenient,quick,and economical outpatient procedure.The main goal of ERBL is to alleviate prolapse,but the high incidence of recurrence and post-procedural pain are of clinical concern.Polidocanol foam as a local hemostatic and anesthetic agent could reduce the rates of post-procedural pain and bleeding.Endoscopic polidocanol foam sclerobanding(EFSB)is a novel approach that could lift the mucosa for easy ligation and promote increased scarring in the submucosal tissue which translates into long-term relief from prolapse recurrence and reduced 24-h postprocedural pain.The study by Qu et al is a novel multi-center prospective randomized study to compare ERBL and EFSB in patients with grades II and III internal hemorrhoids with one-year follow-up.Results showed that EFSB is a novel therapy for internal hemorrhoids,but future studies with a larger sample,multiple treatment sessions,and long-term follow-up are required to confirm these findings. 展开更多
关键词 Internal hemorrhoids Goligher classification Rubber band ligation SCLEROTHERAPY Polidocanol foam
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Endoscopic polidocanol foam sclerobanding for the treatment of Grade Ⅱ-Ⅲ internal hemorrhoids:The focus of clinical practice
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作者 Yu-Yan Zhang Bing Hu 《World Journal of Gastroenterology》 SCIE CAS 2024年第38期4246-4248,共3页
We have read the article by Qu et al with great interest,as it presents an inte-gration of endoscopic polidocanol foam sclerotherapy with rubber band ligation in patients with Grade Ⅱ-Ⅲ internal hemorrhoids.The auth... We have read the article by Qu et al with great interest,as it presents an inte-gration of endoscopic polidocanol foam sclerotherapy with rubber band ligation in patients with Grade Ⅱ-Ⅲ internal hemorrhoids.The authors conducted a prospective,multicenter,randomized study to evaluate the long-term sympto-matic and endoscopic efficacy of this combined intervention.In this discussion,we focus on the procedural steps of this combined strategy and suggest potential avenues for future research. 展开更多
关键词 Internal hemorrhoids Endoscopic therapy Polidocanol foam SCLEROTHERAPY Rubber band ligation Sclerobanding
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Compression properties of cost-efficient porous expanded clay reinforced AA7075 syntactic foams fabricated by industrial-oriented die casting technology
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作者 İsmail Cem Akgün Çağın Bolat Ali Gökşenli 《China Foundry》 SCIE EI CAS CSCD 2024年第1期60-70,共11页
In today’s manufacturing industries,hard competition between rival firms makes it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and anti-pollu... In today’s manufacturing industries,hard competition between rival firms makes it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and anti-pollution.At this point,aluminum syntactic foams(ASFs)are new-generation engineering composites and come into the upfront as a problem-solver.Owing to their features like low density,sufficient elongation,and perfect energy absorption ability,these advanced foams have been considerably seductive for many industrial sectors nowadays.In this study,an industrial-oriented automatic die casting technology was used for the first time to manufacture the combination of AA7075/porous expanded clay(PEC).Micro evaluations(optical and FESEM)reveal that there is a homogenous particle distribution in the foam samples,and inspections are compatible with the other ASF studies.Additionally,T6 aging heat treatment was operated on one half of the produced foams to explore the probable impact of aging on the compressive responses.Attained results show that PEC particles can be an alternative to expensive hollow spheres used in the previous works.Besides,a favorable relationship is ascertained between the aging treatment and mechanical properties such as compression strength and plateau strength. 展开更多
关键词 die casting porous materials metal matrix sytanctic foams expanded clay compressive deformation
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