摘要:

AbstractA variety of fluid space lubricants, i.e., synthetic oils thickened by solid additives (particles of PTFE and MoS2), has been developed. These lubricants present a solid‐like behaviour under yield stress, and a strong non‐Newtonian effect during flow. Measurement of the yield stresses revealed an unexpectedly strong interaction between a synthetic hydrocarbon oil and one type of PTFE particle. Furthermore, the substitution of 1 vol.% PTFE particles by MoS2particles introduced a significant change in the yield stress values. This effect is also apparent in viscosity measurements. These lubricants display, through their rheological behaviour, good ability to replenish contacts over a wide range of temperatures, as shown by measurements taken at −20°C and

ISSN:0265-6582    

DOI:10.1002/jsl.3000150302

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

摘要:

AbstractThe present work describes some structural investigations carried out on commercial and laboratory synthesised polyalphaolefin (PAO) samples. A number of structures having different branched groups along the chain have been identified in the hydrogenated dimer product of 1‐decene, using multi‐pulse13C‐NMR DEPT techniques. These branched structures have been further confirmed by correlating methyl and methine group resonance in the13C‐NMR spectra, using a CALMOD computer program. An insight into the molecular mobility and dynamics of various structures has been obtained through spin lattice relaxation measurement. The study aims to provide a better understanding of the structure—performance relationships in PAOs. A probable mechanism of oligomerisation responsible for the formation of the identified structures is

ISSN:0265-6582    

DOI:10.1002/jsl.3000150303

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

摘要:

AbstractFunctional fluids and additives normally have an ‘R — P’ type of linear chemical structure, where ‘R’ is a linear or isoalkyl chain, and ‘P’ is a mild‐to‐strong polar group. For functional fluids ‘P’ is non‐polar to mildly polar, and for additive molecules it is mild to highly polar. The additive activity depends upon the degree of polarity.Some natural products also have predominantly linear structures in their constituents. Many of these are available in commercial quantities and some even occur as waste. These could be used for the synthesis of functional fluids and additives. This paper covers three groups of such natural products. These are non‐edible vegetable oils, terpenes, and cashew nut shell liquid. The synthesis and characteristics of functional fluids and a variety of possible additives are described. Besides being an alternative non‐petroleum resource, such products have a high degree of biodegradability, as they are deri

ISSN:0265-6582    

DOI:10.1002/jsl.3000150304

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

摘要:

AbstractIt is known that, under electrical or thermal stress, dielectric liquid produces gas. The performance of oil cooled, insulated, or impregnated electrical equipment such as transformers, cables, or capacitors, is affected by the presence of these small gaseous bubbles, which can give rise to partial discharges and to eventual insulation breakdown. Therefore, the gassing properties of an insulating liquid, i.e. its tendency to absorb or evolve gases, have been recognised as a factor of major importance in characterising dielectric liquids. The transition from gas absorption to gas evolution can occur at different temperatures and electrical stresses for different liquids. The effects of temperature, electrical stress, and ageing on gassing tendency have been well studied. Efforts have also been made to correlate the aromatic content of oil with a gassing tendency. However, such studies are limited to mineral insulating transformer oil.In the present work, an effort has been made to study the gassing characteristics of some common dielectric fluids, including linear alkyl benzene (LAB), silicone oil, and capacitor oil, along with some naphthenic and paraffinic transformer oils.

ISSN:0265-6582    

DOI:10.1002/jsl.3000150305

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

摘要:

AbstractThe patient suffers a lot when cystoscopes or catheters are inserted into the urinary system. In order to lower friction whilst being non‐poisonous, nonfungoid, and meeting other medical requirements, a new bionic medical lubricant has been synthesised. In tests imitating the friction condition between skin and plastic apparatus, eel fish synovia, white oil, glycerol, polyethylene glycol in aqueous solution, Tween‐80, a proprietary medical lubricant, and the candidate fluid were tested. The results of these tests demonstrated that the synthesised lubricant performs best, with eel fish synovia second, and glycerol last.The test fluid has been trialled in some key hospitals (Shanghai, Beijing, Guangzhou, and Shijia Zhuang), and the results showed that about 95% of patients experienced no pain, and about 5% had a slight feeling, with no reported discomfort. The candidate bionic medical lubricant is in use by doctors in medical pract

ISSN:0265-6582    

DOI:10.1002/jsl.3000150306

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000150307

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000150308

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000150301

出版商:John Wiley&Sons, Ltd    

年代:1998

数据来源: WILEY