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This study considers the five factors of a car rotation system: angle (F1), arm length (F2), toe in and out (F3), width (F4) and length (F5). The purpose of this paper is to fine tune the design so it produces the smoothest response to various rotation angles.

In the case of Ackerman’s principle, the response surface methodology (RSM) was used to analyze data when encountering different quality characteristics at various rotation angles.

In this study, RSM was used to obtain the best factor and the best reaction value for the five factors of a car rotation system.

In this study, the four-wheel steering of a car is taken as an example. When the current wheel is turned, the intersection of the left and right wheels of the front axle falls on the extension line of the rear wheel. In this case, the steering will be the smoothest. In this example, we selected angle (F1), arm length (F2), toe in and out (F3), width (F4) and length (F5) as experimental factors, hoping to satisfy the Ackerman principle.

Traditionally, when dealing with four-wheel steering problems, solutions may be based on past experience or on new information used to formulate R&D plans. In this study, the combination of statistical factors and optimization is used to find the optimal combination of factors and the relationship between factors.

In the past, most literature relied on kinematics to study the car rotation system due to a lack of experimental design and analysis concepts. However, this study aims to achieve the above goals in finding the solution, which can be used to predict reaction values.

The purpose of this paper is to present the more accurate estimation of aero-heating for the ablative 3-D noses by using the viscous shock layers and similarity of viscous boundary layer methods.

The combination of viscous shock layer, similarity of viscous boundary layer (SVBL) methods, Park ablation and Baldwin–Lomax turbulent models is presented in this paper. The proposed method reduces computational memory and run time as compared to the time marching algorithms during flight trajectory. Therefore, the space marching algorithm and finite difference method is used, and the governing equations are transferred into curvature coordinate by using the mapping terms.

The solving for an ogive nose during flight trajectory shows that the convergence of this technique is fast as compared to the user defined function based on the fluent solvers, program to axisymmetric regular geometry code and other research. The results of this research are validated by the mentioned research studies. The relative error for the aero-heating, species concentration of the shock layer gas mixture because of dissociation/ionization of air and surface ablation results is less than 6, 5 and 11 per cent, respectively.

The required time for an aerodynamic design of hypersonic noses reduces as the induced aero-heating is one of the principal design parameters in standpoint aerodynamic, structural and other terms. The magnitude of this parameter, surface temperature and surface recess because of ablation should be corrected during flight trajectory.

The results of this research are applicable for aerospace industries.

The originality of this paper is 90 per cent.

Toner is a crucial dry colorant composite used in printing based on the electrophotographic process. The quality of printed images is greatly influenced by the toner production method and material formulation. Chemically in situ polymerization methods are currently preferred. This paper aims to optimize the characteristics of a composite produced through emulsion polymerization using common raw materials for electrophotographic toner production.

Emulsion polymerization provides the possibility to optimize the physical and color properties of the final products. Response surface methodology (RSM) was used to optimize variables affecting particle size (PS), PS distribution (PSD), glass transition temperature (T_g°C), color properties (ΔE) and monomer conversion. Box–Behnken experimental design with three levels of styrene and butyl acrylate monomer ratios, carbon black pigment and sodium dodecyl sulfate surfactant was used for RSM optimization. Additionally, thermogravimetric analysis and surface morphology of composite particles were examined.

The results indicated that colorants with small PS, narrow PSDs, spherical shape morphology, acceptable thermal and color properties and a high percentage of conversion could be easily prepared by optimization of material parameters in this method. The anticipated outcome of the present inquiry holds promise as a guiding beacon toward the realization of electrographic toner of superior quality and exceptional efficacy, a vital factor for streamlined mass production.

To the best of the authors’ knowledge, for the first time, material parameters were evaluated to determine their impact on the characteristics of emulsion polymerized toner composites.

The Fay and Riddell (F–R) formula is an empirical equation for estimating the stagnation-point heat flux on noncatalytic and fully catalytic surfaces, based on an assumption of equilibrium. Because of its simplicity, the F–R has been used extensively for reentry flight design as well as ground test facility applications. This study aims to investigate the uncertainties of the F-R formula by considering velocity gradient, chemical species at the boundary layer edge, and the thermochemical nonequilibrium (NEQ) behind the shock layer under various hypersonic NEQ flow environments.

The stagnation-point heat flux calculated with the F–R formula was evaluated by comparison with thermochemical NEQ calculations and existing flight experimental values.

The comparisons showed that the F–R underestimated the noncatalytic heat flux, because of the chemical composition at the surface. However, for fully catalytic heat flux, the F–R results were similar to values of surface heat flux from thermochemical NEQ calculations, because the F–R formula overestimates the diffusive heat flux. When compared with the surface heat flux results obtained from flight experimental data, the F–R overestimated the fully catalytic heat flux. The error was 50% at most.

The results provided guidelines for the F–R calculations under hypersonic flight conditions and for determining the approximate error range for noncatalytic and fully catalytic surfaces.

The purpose of this paper, an R&D project, is to select Globally Harmonized System of Classification and Labeling of Chemicals (GHS)-unclassified white solid lubricants for formulating special lubricating oils, greases and pastes to prevent tribological systems against fretting wear.

The scientific methodology reads as follows: market research to select appropriate additives according to the purpose of the R&D project; screening tests to determine the technical performance of the additives; advanced technical studies and tests to validate the technical performance of the lubricating additives; determination of the reaction layers; and clarification of the build-up mechanism of the reaction layers (practical tests).

The findings of the R&D project can be summarized as follows: the selected white solid lubricants perform in lubricating oils, greases and pastes highly effective against fretting wear. The performance could be shown on the basis of representative test results and highlights its advantages compared to the state of the art.

The research team faced some challenges during the R&D project – the unsuitability of standard test measurements as well as DIN, ISO and ASTM test parameters led to limitations and increased effort.

The motivation and main target to conduct the R&D project was to increase the consumer and operator safety by using unclassified (GHS) high performance lubricants. The findings of the project show clearly that the tasks could be fulfilled. Special, unclassified (GHS) selected white solid lubricants are able to form a reaction layer on metal surfaces and separate effectively the surfaces within the tribological system. No fretting wear accrued. The consumer can gain substantial benefits on the economical side as well as on the ecological side.

The purpose of this paper is to investigate the effect of different PHS on the surface chemistry of fumed silica treated with aminopropyltrimethoxysilane (APTMS).

The reaction conditions involved variation of pH ranging from acidic to alkaline. Different analytical techniques including FT‐IR spectroscopy, thermogravimetric analysis (TGA), CHN and Zeta potential analyses were employed to investigate the surface chemistry of treated particles. In addition, the stability of silanised silica dispersions were studied using turbidimetric and rheometric measurements.

It was revealed that in all conditions silica was more or less chemically grafted by the silane. When the pH of treating bath was adjusted to 1‐2 prior and during the reaction, 58 percent grafting was observed, as obtained by CHN and TGA analyses. At very alkaline conditions, however, the grafting content declined to 29 percent. The variations in grafting were dependent on the silane hydrolysis and its further condensation with the silica surface. Zeta potential measurements showed a drastic change from −7.1 mv to +18.01 mv (at pH 7) for the untreated particle and the one with the highest grafting, respectively. The dispersion stability of differently treated particles varied in solvents with different Hansen solubility parameters (HSP). Moreover, due to the variations of surface chemistry of particles, their rheological behaviours were significantly influenced.

The results obtained in this work showed that the surface chemistry of fume silica could be tuned with treating method. The highest content of grafting led to a better dispersion in solvents having greater hydrogen bonding component and to an inferior dispersion in solvents with higher polar component.

The purpose of this paper is to speak about the production of biodiesel from waste cooking oil which serves as an alternate fuel in the absence of conventional fuels such as diesel and petrol. Though much research work was carried out using non-edible crops such as Jatropha and Pongamia, cooking oil utilized in bulk quantity is discarded as a waste. This is reused again as it contains more of esters that when combined with an alcohol in presence of an enzyme as a catalyst yields triglycerides (biodiesel).

The lipase producing strain Rhizopus oryzae and pure enzyme lipase is immobilized and treated with waste cooking oil for the production of FAME. Reaction parameters such as temperature, time, oil to acyl acceptor ratio and enzyme concentration were considered for purified lipase and in the case of Rhizopus oryzae, pH, olive oil concentration and rpm were considered for optimization studies. The response generated through each run were evaluated and analyzed through the central composited design of response surface methodology and thus the optimized reaction conditions were determined.

A high conversion (94.01 percent) was obtained for methanol when compared to methyl acetate (91.11 percent) and ethyl acetate (90.06 percent) through lipase catalyzed reaction at oil to solvent ratio of 1:3, enzyme concentration of 10 percent at 30°C after 24 h. Similarly, for methanol a high conversion (83.76 percent) was obtained at an optimum pH of 5.5, olive oil concentration 25 g/L and 150 rpm using Rhizopus oryzae when compared to methyl acetate (81.09 percent) and ethyl acetate (80.49 percent).

This research work implies that the acyl acceptors methyl acetate and ethyl acetate which are novel solvents for biodiesel production can also be used to obtain high yields as compared with methanol under optimized conditions.

This study aims to investigate the corrosion inhibitor effect of migrating corrosion inhibitor (MCI) on Q235 steel in high alkaline environment under cathodic polarization.

This study investigated the electrochemical characteristics of Q235 steel with and without MCI by polarization curve and electrochemical impedance spectroscopy. Besides, the surface composition of Q235 steel under different environments was analyzed by X-ray photoelectron spectroscopy. In addition, the migration characteristic of MCI and the adsorption behavior of MCI under cathodic polarization were studied using Raman spectroscopy.

Diethanolamine (DEA) and N, N-dimethylethanolamine (DMEA) can inhibit the increase of Fe(II) in the oxide film of Q235 steel under cathodic polarization. The adsorption stability of DMEA film was higher under cathodic polarization potential, showing a higher corrosion inhibition ability. The corrosion inhibition mechanism of DEA and DMEA under cathodic polarization potential was proposed.

The MCI has a broad application prospect in the repair of damaged reinforced concrete due to its unique migratory characteristics. The interaction between MCIs, rebar and concrete with different compositions has been studied, but the passivation behavior of the steel interface in the presence of both the migrating electric field and corrosion inhibitors has been neglected. And it was investigated in this paper.

To report on research on the alternative surface finish “direct gold on copper”, including reaction mechanism, methods of deposition and end uses.

Examines the deposition reaction of the electroless flash gold plating bath, and the effects of the copper surface roughness and deposition time on the deposit and solderability characteristics.

Direct immersion gold is only partially immersion and mostly electroless in deposition mode. The surface is applicable to soldering for both leaded solder and lead‐free solders. The surface is also wire bondable.

The paper offers details of a new alternative surface finish for use in printed circuit board fabrication as well as in packaging applications. The paper shows the electroless deposition mode of the process. The finish is ideally suited where Rf losses must be minimized. It is suitable for soldering as well as for wire bonding.

The purpose of this paper is to study methods of reacting the surface of the particles of silica sols with silanes, primarily gamma‐glycidoxypropyltrimethoxysilane (GPTMS) and study some basic properties of the modified sols and the nature and structure of the silane groups attached to the particle surface.

The surface of the silica particles was modified by reacting the silica sols with aqueous solutions of silanes, chiefly GPTMS. The presence and structure of silane groups on the particle surface were established by Si‐NMR and C‐NMR, respectively.

Several silanes were studied but silica sols could be readily modified only with GPTMS and glycidoxypropylmethoxydiethoxysilane (GPMDES), most readily if the silanes were pre‐hydrolysed in water. Higher degrees of silylation were preferably done by continuous addition of silane. Lower degrees of modification can be achieved at room temperature by the stepwise addition of the silane solution. The silylation of the silica surface with GPTMS significantly reduces the number of charged surface groups and silanol groups. GPTMS binds covalently to the silica surface and the epoxy ring opens and transforms into a diol. Silica sols modified with GPTMS and GPMDES are stable toward aggregation.

Only organo‐reactive silanes were studied.

This is the first work to study the modification by silanes of silica aquasols with high concentrations of silica. The silane modification can extend the use of silica to areas of applications previously inaccessible to silica sols.