The role of castor oil in epoxy and polyamide systems for coating and adhesive application

Summary  Over the past few years, the challenges of globalisation, consolidation and economical point of view have meant that manufacturers of epoxy formulations have to constantly improve their capability to meet the needs of customers. An active area for advancement is that of epoxy and polyamide resin with castor oil. Generally, people working in the coating industries are familiar with castor oil, but this paper provides information on the new use of castor oil in epoxy and polyamide resin. This novel product (castor oil-modified epoxy resin/castor oil-modified polyamide) provides a previously unattainable combination and improved flexibility and toughness to a variety of ambient cure applications. This communication will review the performance of these castor oil-modified epoxy and polyamide resin surface coatings and adhesives. Based on the results of this study, these systems offer some advantages without much affecting the traditional properties of epoxy and polyamide resin in a variety of applications.     

Mössbauer study of the thermal decomposition of FeS2 in coal

The Mössbauer effect has been used to study the transformations of FeS₂ in four different coals: IL No. 6, Ky $\text{9}\text{14}$, Blacksville No. 2, and Powhatan No. 5. The transformations of FeS₂ in the coals were studied in an inert atmosphere. It was observed that the pyrrhotites formed from FeS₂ have a considerable reduction in the isomer shift at 440 °C as compared to the values obtained in the absence of coal. This effect is associated with the interaction of the pyrrhotites with the coal constituents at high temperatures. There is also a significant line-broadening at 440 °C. This broadening is due either to vacancy motion in the iron sulphides and/or to motional broadening due to particle motion in the coal-derived liquids. The percentage conversion of pyrite to pyrrhotite depends markedly on time as well as type of coal. The weathering of the coal has a detrimental effect on the rate of conversion of pyrite to pyrrhotite. The ferrous sulphate layers covering the pyrite particles hinder the removal of sulphur from that surface. The major factor affecting the $\text{Fe}\text{S}$ ratio is the total amount of sulphur available for H₂S formation. Partial H₂S pressure is the crucial quantity controlling the stoichiometry of the pyrrhotites. Hence, a high percentage of H₂S in the reactor at high temperature will assure the formation of pyrrhotites with a high number of metal vacancies.     

Moisture Distribution and Dewatering Efficiency for Wet Materials

This review paper summarizes current research efforts toward a comprehensive view of wet material dewatering, considering the binding energy as the strength to hold water, and rupture energy given to remove moisture from materials.     

Analysis of the diffusion layer thickness, equivalent circuit and conductance behaviour for reversible electron transfer processes in linear sweep voltammetry

The parametric dependence of the diffusion layer thickness upon electrode potential and scan rate has been derived for reversible electron transfer processes in linear sweep voltammetry (LSV) using a simple analytical expression for the dimensionless current function. The quantitative variation of the conductance with potential and scan rate has been illustrated and the equivalent circuit pertaining to LSV has been proposed. Several earlier results pertaining to potential step experiments, thin layer voltammetry, surface bound LSV, radial flow at micro-ring electrodes, etc. are shown to arise from the general expression for the current function obtained here, thus indicating an isomorphism among various potential perturbation techniques.     

Psychophysical basis for maximum pushing and pulling forces: A review and recommendations

The objective of this paper was to perform a comprehensive review of psychophysically determined maximum acceptable pushing and pulling forces. Factors affecting pushing and pulling forces are identified and discussed. Recent studies show a significant decrease (compared to previous studies) in maximum acceptable forces for males but not for females when pushing and pulling on a treadmill. A comparison of pushing and pulling forces measured using a high inertia cart with those measured on a treadmill shows that the pushing and pulling forces using high inertia cart are higher for males but are about the same for females. It is concluded that the recommendations of Snook and Ciriello (1991) for pushing and pulling forces are still valid and provide reasonable recommendations for ergonomics practitioners. Regression equations as a function of handle height, frequency of exertion and pushing/pulling distance are provided to estimate maximum initial and sustained forces for pushing and pulling acceptable to 75% male and female workers.     

Perceiving,learning, and exploiting object affordances for autonomous pile manipulation

Autonomous manipulation in unstructured environments will enable a large variety of exciting and important applications. Despite its promise, autonomous manipulation remains largely unsolved. Even the most rudimentary manipulation task—such as removing objects from a pile—remains challenging for robots. We identify three major challenges that must be addressed to enable autonomous manipulation: object segmentation, action selection, and motion generation. These challenges become more pronounced when unknown man-made or natural objects are cluttered together in a pile. We present a system capable of manipulating unknown objects in such an environment. Our robot is tasked with clearing a table by removing objects from a pile and placing them into a bin. To that end, we address the three aforementioned challenges. Our robot perceives the environment with an RGB-D sensor, segmenting the pile into object hypotheses using non-parametric surface models. Our system then computes the affordances of each object, and selects the best affordance and its associated action to execute. Finally, our robot instantiates the proper compliant motion primitive to safely execute the desired action. For efficient and reliable action selection, we developed a framework for supervised learning of manipulation expertise. To verify the performance of our system, we conducted dozens of trials and report on several hours of experiments involving more than 1,500 interactions. The results show that our learning-based approach for pile manipulation outperforms a common sense heuristic as well as a random strategy, and is on par with human action selection.     

Analysis of seed oils containing cyclopentenyl fatty acids by combined chromatographic procedures

The fatty acids of seed oils of the Flacourtiaceae,Hydnocarpus anthelmintica, Caloncoba echinata andTaraktogenus kurzii, have been examined by a combination of capillary gas chromatography, silver ion high performance liquid chromatography and gas chromatography-mass spectrometry. In addition to the common range of cyclopentenyl fatty acids found in such oils, 13-cyclopent-2-enyltridec-4-enoic acid was a major component ofH. anthelmintica and was identified by mass spectrometry as its picolinyl ester and dimethyldisulphide adduct. It has not previously been found in nature. In the other seed oils, the isolated double bond in the corresponding fatty acid was in position 6, as expected. Similarly,cis-4-hexadecenoic acid and C₁₆ and C₁₈ cyclopentyl fatty acids were identified for the first time inH. anthelmintica. Iso- andanteiso-methylbranched fatty acids were present in trace amounts.     

Photoinduced graft copolymerization of 2-hydroxyethyl methacrylate on cotton cellulose in the presence of triethyleneglycol dimethacrylate

The addition of a bifunctional monomer, triethylene glycol dimethacrylate (TEGDMA), to a grafting system containing 2-hydroxyethyl methacrylate (HEMA) and benzoin ethyl ether photoinitiator substantially increased the graft add-on of the unswollen and sodium hydroxide–swollen cotton cellulose. Grafting caused changes in the properties of the substrate such as moisture regain, the water of imbibition, and the dyeability with a direct and a reactive dye in accordance with the graft level. The observations have been explained in relation to structural changes in the grafted cotton. © 1994 John Wiley & Sons, Inc.     

Molar volume and ultrasonic studies of europium soaps in mixed organic solvents

The ultrasonic velocity and density measurements of europium soaps in a mixture of benzene and methanol (3:2, vol/vol) were used to evaluate various acoustic parameters and molar volume and to determine the critical micelle concentration. The results showed that the ultrasonic velocity, specific acoustic impedance, molar sound velocity, and molar compressibility increase, and intermolecular free length, adiabatic Compressibility, and relative association decrease with increasing concentration and chainlength of the soap. The results were interpreted in terms of soap-solvent interaction.