Search results

Ultra-high molecular weight polyethylene (UHMWPE) has an excellent performance and application value; however, as a tribological material, its main drawback is its poor performance under dry friction, impacting its ability to work in high-speed dry friction conditions. Modification of UHMWPE can be carried out to overcome these issues. A significant number of inorganic materials have been used to modify UHMWPE and provide it with good tribological performance. However, thus far, there has been no systematic investigation into the methodology of modifying UHMWPE. The authors take a quantitative approach to determine the structure tribo-ability relationship and basic principles of screening of inorganic compounds suited to modify UHMWPE.

The tribological properties of modified UHMWPE using a series of inorganic additives have been qualitatively studied by the authors’ research group previously. In this study, basic quantitative structure tribo-ability relationships (QSTRs) of inorganic additives for modifying UHMWPE were studied to predict tribological properties. A set of 15 inorganic compounds and their tribological data were used to study the predictive capability of QSTR towards inorganic additives properties.

The results show that the anti-wear and friction-reducing properties of these inorganic compounds correlate with the calculated parameters of entropy and dipole moment. Increased entropy and smaller dipole moment can effectively improve the anti-wear and friction-reducing ability of inorganic compounds as UHMWPE additives. Additives with larger molecular weight, lower hardness and lower melting and boiling points provide good tribological properties for UHMWPE. For inorganic compounds to act as UHMWPE additives, the chemical bond should be less covalent and have more ionic character.

Only 15 inorganic compounds and their tribological data were used to study the predictive capability of QSTR towards inorganic additives properties. If the samples number is more than 30, the other QSTR methodology can be used to study the modified UHMWPE, and the models finding can be more precise.

A QSTR model for modified UHMWPE has been studied systematically. While the results are not more precise and detailed, the model provides a new way to explore the modified UHMWPE characteristics and to reveal new insight into the friction and wear process.

Because the method of studying tribological materials is entirely different from others, the authors want to present the works and discuss it with colleagues.

The paper presents a new method to study the modified UHMWPE. A QSTR is used to study the tribology capability of compounds from calculated structure descriptors. This study uses the Hartree–Fock ab initio method to establish a QSTR prediction model to estimate the ability of 15 inorganic compounds to act as anti-wear and friction-reducing additives for UHMWPE.

PART IV Inorganic chemistry textbooks. Seventeen textbooks of inorganic chemistry are considered in this part of the review, and the inorganic sections of the syllabuses of the three GCE Boards previously discussed are analysed.

Examines the fourteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.

An integrated sensor with three elements (zinc oxide, tin oxide and tungsten oxide) was fabricated by thick film techniques in order to develop a smell sensor. Using this sensor and pattern recognition method, the possibility of identifying 15 chemical compounds which belong to the alcohol, ester, ketone, benzene and hydrocarbon group was examined. The following results were obtained: All 15 compounds have different patterns, so they can be individually identified; compounds which have the same functional groups have similar patterns; and, when gas sensitivity of three elements is displayed in a three‐dimensional space, the compounds with the same functional group form a specific closed space. This indicates that the sensor can identify functional groups of chemical compounds.

Chemical Abstracts Service has recently introduced a new data base, CA SEARCH, which is supposed to replace CA CONDENSATES and CASIA, and which is, in effect, a combination of the two. Two major U.S. search services, Lockheed Retrieval Service (LRS) and System Development Corporation (SDC), offer access to CA SEARCH. Bibliographic Retrieval Service (BRS) will also soon load CA SEARCH, but is presently offering CA CONDENSATES.

The paper discusses broadly electronic publishing and types of electronic publications. An attempt has been made to group the select electronic resources of chemical information into portals, patents and dissertations, full‐text files with backfiles and e‐books, abstracting and indexing services, encyclopaedias and handbooks, periodic tables, property databases and specialty databases. The paper concludes that in delivering electronic information two major developments are gaining momentum as archives from major publishers and preprints from academic circles are used as alternative methods of accessing research information. Also, scholarly publication of chemical information in electronic form will continue to grow, adapting to meet changing needs of authors and readers alike.

The purpose of this paper is to study tribological properties of two novel additives in the diester and provide adequate information on the relationship between the diester and the additives.

The two 2‐mercaptobenzothiazole derivatives, referred to as BZIA, BZOA, are synthesized with one pot; their tribological performances are evaluated using a four‐ball friction and wear tester, and the worn surface was analysed with scanning electron microscope and X‐ray photoelectron spectroscopy (XPS).

The two compounds as the additives in the diester possess excellent load‐carrying capacities, rather good anti‐wear (AW) and friction reduction properties. According to the XPS results, both the additives reacted with counter‐face metal and generated a sulphur‐containing inorganic film and a complex adsorption film. The inorganic film obtained with the additive BZOA consisted of FeS₂, FeSO₄ and Fe₂(SO₄)₃, whereas the inorganic film obtained with the additive BZIA consisted of FeS₂ or FeS. The adsorption layer for the two additives contained N‐containing compounds.

The interaction of the two additives with the diester needs to be further explored.

Two useful, environmentally friendly, AW lubricating oil additives are synthesized with one pot.

The paper provides a study of some N, S‐containing heterocyclic compounds as environmentally friendly lubricating oil additives.

PART VI Practical chemistry textbooks and miscellaneous books. Thirty‐nine practical chemistry textbooks were received from publishers for this part of the review and they have been briefly analyzed under the headings Physical, Inorganic, Organic, Quantitative analysis, and Other features, in Tables 1–4. It has not been possible to examine these in the same detail as the theory books previously considered. A number of other books which are used at ‘A/S’ level were also received and these have been tabulated: problem and calculation books in Table 5, and others in Table 6.

Examines the sixteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.

The year 1977 was the first in the tenth collective period (1977‐1981) for Chemical Abstracts. Thus during that year the important and very voluminous Tenth Collective Index began to appear on library shelves, but as this review is being written in 1978 there are still volumes of the formula and chemical substance indexes that have to be added. Librarians will have recently received two Index Guides: one as part of the Ninth Collective Index, and the other as the first Index Guide for the tenth collective period ‐ to be supplemented annually, and finally superseded by the Index Guide which appears as part of the Tenth Collective Index.