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The purpose of this study is to investigate the changes in the performance of ink formulations caused by the addition of compounds that improve the ink’s physical properties to achieve an optimum formulation for inkjet printing, because of the importance and simplicity of this method.

Ink samples were formulated using Acid Red 14 as ink colorant, different percentages of polymeric compounds including polyvinyl alcohol (PVA), polyvinylpyrrolidone and Carboxy methyl cellulose (CMC) as viscosity modifier compounds and surfactant as the surface tension enhancer. Formulated samples were adjusted in terms of fluid physical properties e.g. viscosity, density and surface tension, and the effect of used compounds on the improvement of both physical and colorimetric properties such as viscosity, surface tension, colorimetric coordinates and lightfastness has been evaluated to achieve the optimum printing inks to be printed on three different substrates.

The experimental observations showed that CMC was the most compatible compound as the viscosity modifier as its viscosity value was in the printable range of 2–22 cP. Moreover, a flow-curve test was applied to the ink samples and their Newtonian behavior was approved. Based on the spectrophotometric test results of printed samples, the samples containing PVA provided acceptable lightfastness in comparison to other ink samples on every used substrate.

An optimum relation between colorimetric coordinates of the printed samples and ink formulation could be considered and achieved.

Lubricants for four‐stroke motorcycles have traditionally been rebranded versions of those used for passenger car engine lubrication. Recent developments in passenger car engine oils with the intention of improving fuel utilisation efficiencies were not compatible with some of the specific requirements of four‐stroke motorcycle powertrain lubrication. The effect of using such lubricants on the various components of the motorcycle powertrain, including the engine, clutch, gearbox, starter system drive and back torque limiter is described. The subsequent development of a new specification specifically for use in four‐stroke motorcycles is described.

The purpose of this paper is to develop a high‐throughput approach to optimize printing of pigment‐based formulations.

A total of 40 formulations were robotically prepared by varying the concentrations of diethyleneglycol, glycerol and surfynol. In addition, a variety of inkjet printer (process) variables (voltage, pulse width and frequency) was varied. The combined influence of these two sets of variables on printing performance were determined, analysed and optimised using the Statistical Software Package (MODDE 8), which uses multiple linear regression and partial least square analysis.

The components diethyleneglycol and surfynol were observed to predominantly control viscosity and surface tension of all formulations, which voltage and pulse width were found to be the main factors controlling the spread of the droplet on the substrate.

Optimisation of pigment‐based formulations has typically involved the one‐by‐one systematic variation of components in a stepwise manner. The work reported here allowed the generation of a robust model allowing the properties of any new formulation to be accurately predicted. Importantly, the experimental tools and methods developed can be applied quite generally to the preparation of any new formulation for inkjet printing application.

Experimental design and high‐throughput technology allow new formulations to be accurately predicted for diverse inkjet applications.

The purpose of this paper is to prepare novel types of copolymers and terpolymers depending on jojoba, and using them as additives for lubricating oil.

Copolymerization of 1 mole of jojoba with 2 moles of vinyl acetate and copolymerization of 1 mole of jojoba with 2 moles of vinyl pyrrolidone were carried out. Then, two series of terpolymers were prepared by reacting (jojoba: vinyl acetate: alkylacrylate) and (jojoba: vinyl pyrrolidone: alkylacrylate), using free radical chain addition polymerization. Elucidation of the prepared polymers was carried out by using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and gel permeation chromatography, for determination of weight average molecular weight. The thermal stability of the prepared polymers was determined. The prepared polymers were evaluated as viscosity index improvers and pour point depressants for lubricating oil.

It was found that the viscosity index increases with increasing the alkyl chain length of alkylacrylate. The effect of the monomer type was studied, and it was found that the polymers depending on vinyl acetate have great effect as viscosity index improvers and pour point depressants for lubricating oil.

The polymerization of jojoba as different copolymers and terpolymers was carried out. The great influence of the prepared additives on modification of the viscosity properties and pour point of the oil was observed.

The purpose of this paper is to study the influence of polymeric viscosity improver on the tribological performance of palm kernel methyl ester (PKME).

Tribological performances of the PKME added with the various concentration of ethylene-vinyl acetate copolymer (EVA) were evaluated using four-ball tribotester under extreme pressure condition. The morphologies of the worn surfaces were observed by using the optical microscope.

The addition of polymeric viscosity improver (EVA copolymer) has produced positive results towards the tribological properties of PKME. In total, 4 per cent of EVA copolymer is found as the optimum concentration by improving the friction reducing properties and anti-wear behaviour due to the formation of film thickness between two rubbing surfaces.

This work might contribute to the development of vegetable oils as a new source of environmental-friendly lubricant.

Cavitation in piston-ring lubrication is studied as part of the performance of piston-ring assemblies. Cavitation degrades performance in engineering applications and its effect is that it alters the oil film pressure, generated at the converging-diverging wedge of the interface. Studies tried to shed light to the phenomenon of cavitation and compare it with cavities that have been identified in bearings. The paper aims to discuss this issue.

Lubricant formulations were used for parametric study of oil film thickness (OFT) and friction providing the OFT throughout the stroke and LIF for OFT point measurements. Lubricant formulation affects cavitation appearance and behaviour when fully developed.

Cavitation affects the ring load carrying capacity. Different forms of cavitation were identified and their shape and size (length and width) is dictated from reciprocating speed and viscosity of the lubricant. A clear picture is given from both techniques and friction results give quantifiable data in terms of the effect in wear and cavitation, depending on the lubricant properties.

Engine results are limited due to manufacturing difficulties of visualisation windows and oil starvation. Therefore, full stroke length sized windows were not an option and motoring tests were implemented due to materials limitations (adhesive and quartz windows). Lubricant manufacturer has to give data regarding the chemistry of the lubricants.

The contribution of cavitation in piston-ring lubrication OFT, friction measurements and lubricant parameters that try to shed light to the different forms of cavitation. A link between viscosity, cavitation, shear thinning properties, OFT and friction is given.

The purpose of this paper is to investigate alternatives for four stroke 10w40 motorcycle engine oils. Today, mineral and synthetic‐based lubricants are widely used but because of ecological aspects, which are gaining in importance nowadays and limited resources of mineral oils, environmentally‐friendly biobased lubricants are gaining in importance. Biobased lubricants are also important for using national resources rather than importing crude oils which are limited. The main consumption of lubricant market is motor oils. In this study, starting from mineral, synthetic and biobased lubricants; mineral, synthetic, biomineral and biosynthetic based four stroke motorcycle engine oils (10w40) are prepared, then lubricity properties of the motor oils are determined.

The lubricity tests of the samples are done in a fixed forced lubricity test rig and the motorcycle motor oil preparation are conducted according to ASTM test methods.

The results show that 5 per cent of biobased lubricants will be suitable for preparing 10w40 motor oils in both mineral and synthetic based motor oils. Also improvements in the lubricity properties with the blend with biobased lubricants are seen.

The paper presents biomineral and biosynthetic 10w40 motor oils as alternative candidates for motorcycle motor oils.

A review of new and current products. Additive to improve levelling, slip and scratch resistance

There is a continuous drive in automotive sector to shift from conventional lubricants to environmental friendly ones without adversely affecting critical tribological performance parameters. Because of their favorable tribological properties, chemically modified vegetable oils such as palm trimethylolpropane ester (TMP) are one of the potential candidates for the said role. To prove the suitability of TMP for applications involving boundary-lubrication regime such as cam/tappet interface of direct acting valve train system, a logical step forward is to investigate their compatibility with conventional lubricant additives.

In this study, extreme pressure and tribological characteristics of TMP, formulated with glycerol mono-oleate (GMO), molybdenum dithiocarbamate (MoDTC) and zinc dialkyldithiophosphate (ZDDP), has been investigated using four-ball wear tester and valve train test rig. For comparison, additive-free and formulated versions of polyalphaolefin (PAO) were used as reference. Moreover, various surface characterization techniques were deployed to investigate mechanisms responsible for a particular tribological behavior.

In additive-free form, TMP demonstrated better extreme pressure characteristics compared to PAO and lubricant additives which are actually optimized for conventional base-oils such as PAO, are also proved to be compatible with TMP to some extent, especially ZDDP. During cylinder head tests, additive-free TMP proved to be more effective compared to PAO in reducing friction of cam/tappet interface, but opposite behavior was seen when formulated lubricants were used. Therefore, there is a need to synthesize specialized friction modifiers, anti-wear and extreme pressure additives for TMP before using it as engine lubricant base-oil.

In this study, additive-free and formulated versions of bio-lubricant are tested for cam/tappet interface of direct acting valve train system of commercial passenger car diesel engine for the very test time. Another important aspect of this research was comparison of important tribological performance parameters (friction torque, wear, rotational speed of tappet) of TMP-based lubricants with conventional lubricant base oil, that is, PAO and its formulated version.