Inspired by the idea that bionic non-smooth surfaces(BNSS) can reduce fluid adhesion and resistance, and the effect of bionic V-riblet non-smooth structure arranged in tire tread pattern grooves surface on anti-hydrop...Inspired by the idea that bionic non-smooth surfaces(BNSS) can reduce fluid adhesion and resistance, and the effect of bionic V-riblet non-smooth structure arranged in tire tread pattern grooves surface on anti-hydroplaning performance was investigated by using computational fluid dynamics(CFD). The physical model of the object(model of V-riblet surface distribution, hydroplaning model) and SST k-ω turbulence model were established for numerical analysis of tire hydroplaning. With the help of a orthogonal table L16(45), the parameters of V-riblet structure design compared to the smooth structure were analyzed, and obtained the priority level of the experimental factors as well as the best combination within the scope of the experiment. The simulation results show that V-riblet structure can reduce water flow resistance by disturbing the eddy movement in boundary layers. Then, the preferred type of V-riblet non-smooth structure was arranged on the bottom of tire grooves for hydroplaning performance analysis. The results show that bionic V-riblet non-smooth structure can effectively increase hydroplaning velocity and improve tire anti-hydroplaning performance. Bionic design of tire tread pattern grooves is a good way to promote anti-hydroplaning performance without increasing additional groove space, so that tire grip performance and roll noise are avoided due to grooves space enlargement.展开更多
The adsorption of sulfate in aqueous solutions onto organo-nano-clay prepared by natural zeolite and cationic surfactant cetyltrimethylammonium bromide （CTAB） was studied.Parameters such as adsorbent dosage,contact ...The adsorption of sulfate in aqueous solutions onto organo-nano-clay prepared by natural zeolite and cationic surfactant cetyltrimethylammonium bromide （CTAB） was studied.Parameters such as adsorbent dosage,contact time and temperature were investigated using batch adsorption studies.The results show that the uptake of sulfate increases with the increase of contact time and temperature,and decreases with the increase of dosage.The Freundlich isotherm model is fit to explain the sulfate adsorption onto organo-nano-clay.The maximum adsorption capacity is found to be 38.02 mg/g at 40 ℃.The kinetic data fit well the pseudo-second-order and Elovich models with a R2 more than 0.98.It is suggested that chemisorption is the rate-controlling step for adsorption of sulfate onto organo-nano-clay,meanwhile both intraparticle diffusion and boundary layer diffusion also contribute as well.Ion-exchange between sulfate anions and bromide ions and complexation between sulfate anions and CTAB cations are responsible for the mechanism of sulfate adsorption.Keywords：organo-nano-clay; cetyltrimethylammonium bromide （CTAB）; modification; sulfate; adsorption展开更多
Heavy metal determination was carried out by applying the solid phase extraction （SPE） method in batch mode followed by atomic absorption spectroscopy （AAS） and inductively coupled plasma atomic emission spectrosc...Heavy metal determination was carried out by applying the solid phase extraction （SPE） method in batch mode followed by atomic absorption spectroscopy （AAS） and inductively coupled plasma atomic emission spectrosco py （ICP-AES） from aqueous solutions using Ghezeljeh montmorillonite nanoclay as a new natural adsorbent. The Ghezeljeh clay is characterized by using Fourier Transform Infrared （FT-IR） Spectroscopy, Scanning Electron Mi- croscopy-Energy Dispersive Spectrometry （SEM-EDS） and X-ray Diffractometry （XRD） and X-ray Fluorescence （XRF）. The results of XRD and FT-IR of nanoclay confirm that montmorillonite is the dominant mineral phase. Based on SEM images of Ghezeljeh clay, it can be seen that the distance between the plates is Nano. The effects of varying parameters such as initial concentration of metal ions, pH and type of buffer solutions, amount of ad- sorbent, contact time, and temperature on the adsorption process were examined. The effect of various interfer- ing ions was studied. The adsorption data correlated with Freundlich, Langmuir, Dubinin-Radushkevich （D-R）, and Temkin isotherms. The Langmuir and Freundlich isotherms showed the best fit to the equilibrium data for Hg（II）, but the equilibrium nature of Cu（ll） adsorption has been described by the Langmuir isotherm. The kinetic data were described with pseudo-first-order, pseudo-second-order and double-exponential models, The adsorp- tion process follows a pseudo-second-order reaction scheme, Calculation of AGσ, △Hσ and ASσ showed that tilenature of Hg（II） ion sorption onto the Ghezeljeh nanoclay was endothermic and was favored at higher temper- attire, and the nature of Cu（II） ion sorption was exothermic and was favored at lower temperature,展开更多
The gradient model of two-dimensional defectless medium is formulated. A graphene sheet is examined as an example of such two-dimensional medium. The problem statement of a graphene sheet deforming in its plane and th...The gradient model of two-dimensional defectless medium is formulated. A graphene sheet is examined as an example of such two-dimensional medium. The problem statement of a graphene sheet deforming in its plane and the bending problem are examined. It is ascertained that the statement of the first problem is equivalent to the flat problem statement of Toupin gradient theory. The statement of the bending problem is equivalent to the plate bending theory of Timoshenko with certain reserves. The characteristic feature of both statements is the fact that the mechanical properties of the sheet of graphene are not defined by “volumetric” moduli but by adhesive ones which have different physical dimension that coincides with the dimension of the corresponding stiffness of classical and nonclassical plates.展开更多
The study of the adhesion of millions of setae on the toes of geckos has been advanced in recent years with the emergence of new technology and measurement methods. The theory of the mechanism of adhesion by van der W...The study of the adhesion of millions of setae on the toes of geckos has been advanced in recent years with the emergence of new technology and measurement methods. The theory of the mechanism of adhesion by van der Waals forces is now accepted and broadly understood. However, this paper presents limitations of this theory and gives a new hypothesis of the biomechanism of gecko adhesion. The findings are obtained through measurements of the magnitude of the adhesion of setae under three different conditions, to show the close relationship between adhesion and status of the setae. They are reinforced by demonstrating two setal structures, follicle cells and hair, the former making the setae capable of producing bioelectrical charges, which play an important role in attachment and detachment processes. It is shown that the abundant muscular tissues at the base of the setae cells, which are controlled by peripheral nerves, are instrumental in producing the foot movement involved in attachment and detachment. Our study will further uncover the adhesion mechanism of geckos, and provide new ideas for designing and fabricating synthetic setae.展开更多
基金Project(51405201)supported by the National Natural Science Foundation of ChinaProject(1291120046)supported by the Jiangsu University Advanced Talents Initial Funding,China+1 种基金Project(QC201303)supported by the Open Fund of Automotive Engineering Key Laboratory,ChinaProject(2014M551509)supported by the China Postdoctoral Science Foundation
文摘Inspired by the idea that bionic non-smooth surfaces(BNSS) can reduce fluid adhesion and resistance, and the effect of bionic V-riblet non-smooth structure arranged in tire tread pattern grooves surface on anti-hydroplaning performance was investigated by using computational fluid dynamics(CFD). The physical model of the object(model of V-riblet surface distribution, hydroplaning model) and SST k-ω turbulence model were established for numerical analysis of tire hydroplaning. With the help of a orthogonal table L16(45), the parameters of V-riblet structure design compared to the smooth structure were analyzed, and obtained the priority level of the experimental factors as well as the best combination within the scope of the experiment. The simulation results show that V-riblet structure can reduce water flow resistance by disturbing the eddy movement in boundary layers. Then, the preferred type of V-riblet non-smooth structure was arranged on the bottom of tire grooves for hydroplaning performance analysis. The results show that bionic V-riblet non-smooth structure can effectively increase hydroplaning velocity and improve tire anti-hydroplaning performance. Bionic design of tire tread pattern grooves is a good way to promote anti-hydroplaning performance without increasing additional groove space, so that tire grip performance and roll noise are avoided due to grooves space enlargement.
基金Project(51178159)supported by the National Natural Science Foundation of ChinaProject(CXZZ12_0236)supported by the Postgraduate Technological Innovation Program of Jiangsu Province Education Department,China
文摘The adsorption of sulfate in aqueous solutions onto organo-nano-clay prepared by natural zeolite and cationic surfactant cetyltrimethylammonium bromide （CTAB） was studied.Parameters such as adsorbent dosage,contact time and temperature were investigated using batch adsorption studies.The results show that the uptake of sulfate increases with the increase of contact time and temperature,and decreases with the increase of dosage.The Freundlich isotherm model is fit to explain the sulfate adsorption onto organo-nano-clay.The maximum adsorption capacity is found to be 38.02 mg/g at 40 ℃.The kinetic data fit well the pseudo-second-order and Elovich models with a R2 more than 0.98.It is suggested that chemisorption is the rate-controlling step for adsorption of sulfate onto organo-nano-clay,meanwhile both intraparticle diffusion and boundary layer diffusion also contribute as well.Ion-exchange between sulfate anions and bromide ions and complexation between sulfate anions and CTAB cations are responsible for the mechanism of sulfate adsorption.Keywords：organo-nano-clay; cetyltrimethylammonium bromide （CTAB）; modification; sulfate; adsorption
基金financial support for this work by the Imam Khomeini International University (IKIU)Mines and Mining Industries Development and Renovation Organization of Iran (IMIDRO)
文摘Heavy metal determination was carried out by applying the solid phase extraction （SPE） method in batch mode followed by atomic absorption spectroscopy （AAS） and inductively coupled plasma atomic emission spectrosco py （ICP-AES） from aqueous solutions using Ghezeljeh montmorillonite nanoclay as a new natural adsorbent. The Ghezeljeh clay is characterized by using Fourier Transform Infrared （FT-IR） Spectroscopy, Scanning Electron Mi- croscopy-Energy Dispersive Spectrometry （SEM-EDS） and X-ray Diffractometry （XRD） and X-ray Fluorescence （XRF）. The results of XRD and FT-IR of nanoclay confirm that montmorillonite is the dominant mineral phase. Based on SEM images of Ghezeljeh clay, it can be seen that the distance between the plates is Nano. The effects of varying parameters such as initial concentration of metal ions, pH and type of buffer solutions, amount of ad- sorbent, contact time, and temperature on the adsorption process were examined. The effect of various interfer- ing ions was studied. The adsorption data correlated with Freundlich, Langmuir, Dubinin-Radushkevich （D-R）, and Temkin isotherms. The Langmuir and Freundlich isotherms showed the best fit to the equilibrium data for Hg（II）, but the equilibrium nature of Cu（ll） adsorption has been described by the Langmuir isotherm. The kinetic data were described with pseudo-first-order, pseudo-second-order and double-exponential models, The adsorp- tion process follows a pseudo-second-order reaction scheme, Calculation of AGσ, △Hσ and ASσ showed that tilenature of Hg（II） ion sorption onto the Ghezeljeh nanoclay was endothermic and was favored at higher temper- attire, and the nature of Cu（II） ion sorption was exothermic and was favored at lower temperature,
文摘The gradient model of two-dimensional defectless medium is formulated. A graphene sheet is examined as an example of such two-dimensional medium. The problem statement of a graphene sheet deforming in its plane and the bending problem are examined. It is ascertained that the statement of the first problem is equivalent to the flat problem statement of Toupin gradient theory. The statement of the bending problem is equivalent to the plate bending theory of Timoshenko with certain reserves. The characteristic feature of both statements is the fact that the mechanical properties of the sheet of graphene are not defined by “volumetric” moduli but by adhesive ones which have different physical dimension that coincides with the dimension of the corresponding stiffness of classical and nonclassical plates.
基金supported by the National Basic Research Program of China (Grant No. 2011CB302106)the National Natural Science Foundation of China (Grant Nos. 30770285, 51175249, 61175105 and 51105201)the Jiangsu Natural Science Foundation (Grant No. BK2009376)
文摘The study of the adhesion of millions of setae on the toes of geckos has been advanced in recent years with the emergence of new technology and measurement methods. The theory of the mechanism of adhesion by van der Waals forces is now accepted and broadly understood. However, this paper presents limitations of this theory and gives a new hypothesis of the biomechanism of gecko adhesion. The findings are obtained through measurements of the magnitude of the adhesion of setae under three different conditions, to show the close relationship between adhesion and status of the setae. They are reinforced by demonstrating two setal structures, follicle cells and hair, the former making the setae capable of producing bioelectrical charges, which play an important role in attachment and detachment processes. It is shown that the abundant muscular tissues at the base of the setae cells, which are controlled by peripheral nerves, are instrumental in producing the foot movement involved in attachment and detachment. Our study will further uncover the adhesion mechanism of geckos, and provide new ideas for designing and fabricating synthetic setae.
