Corrosion behavior and mechanism of the automotive hot-dip galvanized steel with alkaline mud adhesion

The corrosion behavior and mechanism of hot-dip galvanized steel and interstitial-free （IF） substrate with alkaline mud adhesion were investigated by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, electrochemical impedance spectroscopy （EIS）, and linear polarization. The results show that non-uniform corrosion occurs on the galvanized steel and IF substrate during 250 h with the mud adhesion. The corrosion products on the galvanized steel are very loose and porous, which are mainly ZnO, Zn5（OH）8C12·H2O and Zn（OH）2, and Fe-Zn alloy layer with a lower corrosion rate is exposed on the galvanized steel surface; however, the corrosion products on IF substrate are considerably harder and denser, whose compositions of rust are mainly FeOOH and Fe3O4, and several pits appear on their surface. The results of continuous EIS and linear polarization measurements exhibit a corrosion mechanism, that is, under activation control, the charge transfer resistances present different tendencies between the galvanized steel and IF substrate; in addition, the evolution of linear polarization resistances is similar to that of charge transfer resistances. The higher contents of dissolved oxygen and Cl^- ions in the mud play an important role in accelerating the corrosion.

The Adhesion and Formation Mechanism of Blast Furnace Gunning Layer

Basing on the study of the equilibrium relationship of interfacial tension among gunning particles, repaired surface and atmosphere, this test is in a position to draw a conclusion concerning the adhesion mechanism of the grinning refractory and the repaired surface, which illustrates the formation of the bottom gunning layer by moist fine gunning particles on the repaired surface. Also involved within the scope of discussion and probe are the patterns formed under this contacting effect and the formation mechanism of gunning layer. The analytic research regarding the behavior of gunning interface has ascribed the influence upon adhesion intensity to the quality of furnace gunning refractory, the state of the repaired surface and the gunning techniques.

Adhesive Contact in Animal： Morphology, Mechanism and Bio-Inspired Application

Many animals possess adhesive pads on their feet, which are able tO attach to various substrates while controlling adhesive forces during locomotion. This review article studies the morphology of adhesive devices in animals, and the physical mechanisms of wet adhesion and dry adhesion. The adhesive pads are either ＇smooth＇ or densely covered with special adhesive setae. Smooth pads adhere by wet adhesion, which is facilitated by fluid secreted from the pads, whereas hairy pads can adhere by dry adhesion or wet adhesion. Contact area, distance between pad and substrate, viscosity and surface tension of the liquid filling the gap between pad and substrate are the most important factors which determine the wet adhesion. Dry adhesion was found only in hairy pads, which occurs in geckos and spiders. It was demonstrated that van der Waals interaction is the dominant adhesive force in geckos＇ adhesion. The bio-inspired applications derived from adhesive pads are also reviewed.

Probing the mechanosensitivity in cell adhesion and migration: Experiments and modeling

Cell adhesion and migration are basic physiolog- ical processes in living organisms. Cells can actively probe their mechanical micro-environment and respond to the ex- ternal stimuli through cell adhesion. Cells need to move to the targeting place to perform function via cell migration. For adherent cells, cell migration is mediated by cell-matrix adhesion and cell-cell adhesion. Experimental approaches, especially at early stage of investigation, are indispensable to studies of cell mechanics when even qualitative behaviors of cell as well as fundamental factors in cell behaviors are unclear. Currently, there is increasingly accumulation of ex- perimental data of measurement, thus a quantitative formula- tion of cell behaviors and the relationship among these fun- damental factors are highly needed. This quantitative under- standing should be crucial to tissue engineering and biomed- ical engineering when people want to accurately regulate or control cell behaviors from single cell level to tissue level. In this review, we will elaborate recent advances in the ex- perimental and theoretical studies on cell adhesion and mi- gration, with particular focuses laid on recent advances in experimental techniques and theoretical modeling, through which challenging problems in the cell mechanics are sug- gested.

Mechanical Properties of Graphene within the Framework of Gradient Theory of Adhesion

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.

The application of reed-vibration mechanical spectroscopy for liquids to detect chemical reactions of an acrylic structural adhesive

There remain a number of unsolved problems about chemical reactions, and it is significant to explore new detection methods because they always offer some unique information about reactions from new points of view. For the first time, the solidification course of a modified two-component acrylic structural adhesive is measured by using reed-vibration mechanical spectroscopy for liquids （RMS-L） in this work, and results show that there are four sequential processes of mechanical spectra with time. The in-depth analyses indicate that RMS-L can detect in real-time the generation and disappearance of active free radicals, as well as the chemical cross-link processes in the adhesive. This kind of real-time detection will undoubtedly facilitate the study of the chemical reaction dynamics controlled by free radicals.

Different antibacterial mechanisms of titania nanotube arrays at various growth phases of E.coli

To clarify the antibacterial behavior at early adhesion,two titania nanotube(TNT)arrays were fabricated on polished commercially pure titanium(Ti),and the interaction mechanisms between TNT arrays and the model bacteria(Escherichia coli,E.coli)were investigated.The results show that TNT arrays exhibit a significant early antibacterial effect,which is highly related to the surface free energy and nano-topography.The underlying antibacterial mechanisms include:(1)the anti-initial-attachment effect at the lag phase(0−4 h);(2)the anti-proliferation and physical bactericidal effects at the logarithmic phase(4−12 h);(3)the reduced antimicrobial properties probably due to the overgrowth of bacteria on TNT arrays at the stationary phase(12 h and then).

Diffusive-stochastic-viscoelastic model on specific adhesion of viscoelastic solids via molecular bonds

A diffusive-stochastic-viscoelastic model is proposed for the specific adhesion of viscoelastic solids via stochastically formed molecular bonds. In this model, we assumed that molecular level behaviours, including the diffusion of mobile adhesion molecules and stochastic reaction between adhesion molecules and binding sites, obey the Markovian stochastic processes, while mesoscopic deformations of the viscoelastic media are governed by continuum mechanics. Through Monte Carlo simulations of this model, we systematically investigated how the competition between time scales of molecular diffusion, reaction, and deformation creep of the solids may influence the lifetime and dynamic strength of the adhesion. We revealed that there exists an optimal characteristic time of molecule diffusion corresponding to the longest lifetime and largest adhesion strength, which is in good agreement with experimental observed characteristic time scales of molecular diffusion in cell membranes. In addition, we identified that the media viscosity can significantly increase the lifetime and dynamic strength, since the deformation creep and stress relaxation can effectively reduce the concentration of interfacial stress and increases the rebinding probability of molecular bonds.

An efficient method for enhancing adhesion and uniformity of Al_(2)O_(3) coatings on nickel micro-foam used in micropacked beds

Methods of coating Al_(2)O_(3) on nickel micro-foam were compared and screened,aiming to overcome the capillary force and prepare the micro-foam monolithic catalyst coatings.The surface of micro-foam substrate was pretreated by a chemical etching method to improve the adhesion of the coatings on the substrate.The results showed that the slurry circulation at 162 ml·min^(-1) was evaluated as the optimal method.The pore size on the substrate surface can be controlled by changing the pretreatment conditions.An empirical correlation was also proposed,showing an excellent practicality for predicting the pore size.The adhesion of the coatings with substrate pretreatment was significantly better than that without substrate pretreatment.The minimum value of mass loss after ultrasonic vibration was 3.9%.This mainly attributes to the squeezing of Al_(2)O_(3) particles in the pores of substrate surface.The coatings on nickel micro-foam are hopefully used in micropacked beds for catalytic reactions.

Adhesion coefficient of automobile tire and road surface

The adhesion coefficient of automobile tire and road surface was analyzed and the formula about it was derived.Some suggestions about highway construction,driving safety of the drivers and the judgment of the traffic accidents were presented.The results show that the adhesion coefficient is a function with the extreme value.If there is atmospheric pressure in the tire,the load of the vehicle and the degree of the coarse on the road surface is not selected properly,it will reach the least and affect the safety of the running automobile.

Contact radius of stamps in reversible adhesion

A mechanics model is developed for the contact radius of stamps with pyramid tips in transfer printing.This is important to the realization of reversible control of adhesion,which has many important applications,such as climbing robots,medical tapes,and transfer printing of electronics.The contact radius is shown to scale linearly with the work of adhesion between the stamp and the contacting surface,and inversely with the plane-strain modulus of the stamp. It also depends on the cone angle and tip radius of the stamp,but is essentially independent of details of the tip geometry.

A Boron-based Adhesion Aid for Efficient Bonding of Silicone Rubber and Epoxy Resin

We improved the adhesion between silicon based insulating materials and epoxy resin composites by adding the adhesion promoter cycloborosiloxane(BSi,cyclo-1,3,3,5,7,7-hexaphenyl-1,5-diboro-3,7-disiloxane).The experimental results show that the addition of BSi in the silicone rubber(SR)system significantly increases the tensile shear strength between BSi and epoxy resin(EP),reaching 309%of the original value.On this basis,the mechanism of BSi to enhance the adhesion effect was discussed.The electron deficient B in BSi attracted the electron rich N and O in EP to enhance the chemical interaction,combined with the interfacial migration behavior in the curing process,to improve the adhesion strength.This study provides the design and synthesis ideas of adhesive aids,and a reference for further exploring the interface mechanism of epoxy resin matrix composites.

Importance of Dynamic Mechanical Analysis to Predict Performance of the Polyvinyl Acetate Wood Adhesives in Summer Season

Conventionally available Polyvinyl acetate (PVAc) wood glues are polyvinyl alcohol (PVA) stabilized, with drawbacks like poor strength at high humidity, poor strength at high temperature and workability at low-temperature. PVAc is non-resistant to high humidity, and if such adhesive bonds are exploited in a highly humid environment, its strength substantially decreases. Sufficiently water-resistant adhesive bonds are achieved by modifying PVAc dispersion with special chemicals like acrylic acid (AA) and N-methylol acrylamide (NMA) as a co-monomer, Silanes, and ethylene modified PVA. The Lewis acids like aluminium chloride and aluminium nitrate are used as cross-linkers. So PVAc adhesives are classified as reactive and non-reactive glue. Application of non-reactive D1 (as per EN 204-205) and reactive D2 and D3 (as per EN 204-205) adhesives for bonding laminate on plywood is a regular practice in the Indian market. In summer time, Crack formation was seen in laminate bonded with reactive D2 and D3 adhesives in regions where the room temperature was above 45°C. However, if the same laminate substrates were bonded with non-reactive D1, no cracks were seen. To analyse the above phenomenon, we have done Dynamic mechanical analysis of non-reactive D1, reactive D2 and D3 adhesive.

<i>In Vitro</i>Evaluation of Bacterial Adhesion to Dental and Stainless-Steel Surfaces

This study aimed to describe the factors associated with biofilms formation in dental pathology by comparison of bacterial growth on dental and stainless-steel surfaces. We studied in vitro the behavior of Staphylococcus aureus Métis in order to observe the capacity of adhesion, to evaluate quantitatively the potential of proliferation and to compare the behavior of this germ in contact with the two surfaces. The biomaterials used were cylinders in Stainless steel (AISI 316L), dental fragments and stainless-steel fragments, all were disinfected for 15 minutes and then sterilized in a wet autoclave at 120˚C for 30 min. Macroscopic observation with a binocular magnifier of bacterial proliferation was carried out regularly after 6 h and 24 h of incubation. Observation by optical microscope based on GRAM staining made it possible to visualize the presence or absence of bacteria and to differentiate them. The adhesion of Staphylococcus aureus Méti S on dental fragments was compared to the one obtained on stainless steel fragments. We also carried a Bacterial count by optical dosing. The results show that the ability of this germ to colonize and develop biofilms on surfaces depends mainly on the characteristics of the surface. Rough surfaces as dental surface are more likely to developing biofilms than smooth surfaces like stainless-steel surface.

Specific adhesion of a soft elastic body on a wavy surface

This paper aims at developing a stochastic-elastic model of a soft elastic body adhering on a wavy surface via a patch of molecular bonds. The elastic deformation of the system is modeled by using continuum contact mechanics, while the stochastic behavior of adhesive bonds is modeled by using Bell＇s type of exponential bond association/dissociation rates. It is found that for sufficiently small adhesion patch size or stress concentration index, the adhesion strength is insensitive to the wavelength but decreases with the amplitude of surface undulation, and that for large adhesion patch size or stress concentration index, there exist optimal values of the surface wavelength and amplitude for maximum adhesion strength.

Analysis of Related Problems of Pelvic Abdominal Adhesion

Pelvic abdominal adhesion is a major problem in obstetrics and gynecology.The occurrence of adhesion complications,the difficulty and risk of adhesion reoperation,and the problem of postoperative adhesion not only cause great trouble to the physical and mental health of patients,but also increase the economic burden for the family and social medical system.

Soil conditioning of clay based on interface adhesion mechanism:Microscopic simulation and laboratory experiment

Clogging frequently occurs in the cutter head,excavation chamber or screw conveyor when an earth pressure balance(EPB)shield machine is tunneling in soft or silty clay ground with high clay mineral content.In this paper,montmorillonite,kaolinite,and illite were selected as research objects,and molecular dynamics simulation and laboratory experiment were adopted.At the microscopic scale,dynamic contact behavior and interfacial mechanical behavior of the interface between clay minerals and water/surfactant solution was simulated and the interfacial adhesion and conditioning mechanism between clay minerals and water/surfactant solution was revealed.Thus,sodium dodecyl benzene sulfonate surfactant was selected as the main composition of the soil conditioner.Then,the adhesion stress before and after soil conditioning and the contact angles between clay minerals and water/surfactant solution were tested and analyzed at the macroscopic scale.The result shows that the contact angle between droplet and clay mineral surface is an important parameter to characterize soil adhesion.The simulation rules of the microscopic contact angle are consistent with the experiment results.Furthermore,the adsorption energy between microscopic substances is dominated by electrostatic force,which can reflect the adhesion stress between macroscopic substances.Soil adhesion stress can be effectively decreased by adding the surfactant to the soil conditioner.

Reinforcing Effect of Graphene in Epoxy Adhesives: Review

Due to its great strength, hardness, and chemical resistance, epoxy adhesives are becoming more and more used. They continue to have drawbacks, nevertheless, such as poor thermal stability, and poor electrical conductivity. Two-dimensional graphene is a wonderful substance with exceptional qualities including high strength, high electrical conductivity, and large surface area. Because of these characteristics, graphene has been thoroughly researched for its prospective uses in a variety of industries, including electronics, energy storage, and biomedical engineering. The use of graphene as an additive in epoxy adhesives to enhance the characteristics of such materials is one of its promising uses. This paper reviewed the latest findings about graphene’s effects on epoxy adhesives. The various methods to produce graphene-epoxy composites and their improvements are discussed. This research additionally discusses the challenges associated with the production and processing of graphene-epoxy composites, as well as the mechanisms behind the improvements in mechanical, electrical, and thermal characteristics. The final section of this review discusses the challenges and prospective uses of graphene in epoxy adhesives in the future.

NEW MECHANISM OF LIMITED-SLIP DIFFERENTIAL

According to property requirement of differential, create a new mechanism, which is a combination of a paralleogram linkage and a inverse parallelogram linkage,to replace conventional bevel gears of differential and point out that using the new mechanism the differential can meet the needs of the requirements of torque and speed of the two axle shafts. The instantaneous speed ratio (ISR) which is the left and right half-shaft with respect to differential shell is variable. The calculating result of the locking factor of the new mechanism is up to 3. The limited-slip capability increase twice. The mechanism is an ideal new type of mechanism of differential.

Microstructure,mechanical properties and dry wear resistance of β-type Ti-15Mo-xNb alloys for biomedical applications

In order to study the effect of element Nb on the microstructure and properties of the biomedical β-type Ti-Mo based alloys,Ti-15Mo-xNb（x=5,10,15 and 20 in %） alloys were investigated.The dry wear resistance of β-type Ti-15Mo-xNb alloys against Gr15 ball was investigated on CJS111A ball-disk wear instrument.Experimental results indicate that crystal structure and morphology of the Ti-15Mo-xNb alloys are sensitive to their Nb contents.Ti-15Mo-xNb alloys match those for β phase peaks and no any phases are found.The Vickers hardness values of all the Ti-15Mo-xNb alloys are higher than HV200.The compression yield strength of the Ti-15Mo-5Nb alloy is the lowest and that of the Ti-15Mo-10Nb alloy is the highest.For all the Ti-15Mo-xNb alloys,the friction coefficient is not constant but takes a higher value.In dry condition,SEM study reveals deep parallel scars on the wear surfaces of all the Ti-15Mo-xNb alloys under different loads.The friction coefficient of the Ti-15Mo-5Nb alloy under 1 N is the lowest.The wear principal mechanism for Ti-15Mo-xNb alloys is adhesive wear.