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“The properties of conventional coolants are limited by the natural characteristics of their hydrocarbon bases which can only be varied slightly by complex formulation, whereas a single synthetic coolant can be formulated to cover a wide range of machining operations”.

Discusses environmental factors which may have harmful effects on the cardiovascular system and cause acute or chronic disease. Classifies these factors as chemical, physical, biological and psychosocial. Concentrates on describing the chemical, physical and biological elements which directly cause cardiovascular diseases, such as nicotine and carbon monoxide (chemical); temperatue and electricity (physical) and viral infections such as maternal coxsackie (biological). Concludes by stressing the need for more intensive studies on this subject.

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.

This paper aims to investigate the mechanical and thermal behavior, i.e. tensile strength, hardness, impact strength and glass transition temperatures of water-treated polyamide6/boric oxide (PA) composites.

The PA6 and PA6/boric oxide composites were exposed to an open environment and immersed in water for 15 days to analyze the effect of environmental humidity and frequent water immersion conditions on the composite’s mechanical and thermal properties. The tensile strength, elastic modulus, hardness and impact strength of materials were measured to identify the mechanical properties. The scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) characterizations were used to see the effect of humidity/water absorption on microstructure, crystallinity and glass transition temperatures.

The testing results revealed the loss in strength, elastic modulus and hardness, while the impact resistance was improved after exposure of materials to humidity/water. SEM images clearly show the formation of voids and XRD graphs revealed the loss in crystallinity after water immersion. The DSC plots of water immersed materials revealed the loss of glass transition temperatures up to 15°C.

The mechanical and thermal behavior of PA composites varies according to the surrounding atmosphere. Experiments were performed to investigate the influence of water treatment on the PA6/B₂O₃ composite’s mechanical and thermal properties. Water treatment resulted in the bonding between PA and water molecules, which generated voids in the materials. These voids generations are found the main reason for the low strength and hardness of water-treated materials.

This paper details the use of isophthalic acid and trimellitic anhydride for the design and production of water reducible alkyd coatings. The performance of these systems is equal to or better than conventional solvent based systems. The use of special processing, compounding or application equipment is not required for the production of these coatings, however, the raw materials must be carefully selected to ensure optimum performance. Both water reducible alkyds and water reducible acrylated alkyds for air drying and force cured applications will be discussed. Coatings manufacturers in the United States have commercialized these systems for applications varying from air dry implement enamels to interior can coatings.

This paper aims to confirm that increasing the hardness of thrust collars can improve the load carrying capacity (LCC) and wear resistance of water lubricated thrust bearings (WTBs) made of polymers paired with non-polymeric thrust collars, and to design a WTB with high LCC and durability for a shaftless pump-jet propulsor of an autonomous underwater vehicle. Six kinds of WTBs were manufactured by matching aluminum bronze, stainless steel and silicon nitride with two different polymer bearing materials. Their tribological behaviors were tested and compared.

The tribological behaviors of the WTBs made with different materials were investigated experimentally on a specially designed test rig.

Aluminum bronze is not suitable for crafting thrust collars of heavy load WTBs due to severe abrasive wear. Two body abrasive wear first occurred between the thrust collar and the polymer bearing. Next, aluminum bronze wear particles were produced. The particles acted between the two materials and formed three body abrasive wear. Stainless steel/polymer bearings showed better wear resistance while Si₃N₄/polymer bearings were the best. Improving the hardness of thrust collars is significant to the LCC and service life of WTBs.

The wear mechanism of WTBs under heavy load conditions was revealed. Improving the hardness of the thrust collar was confirmed to be a preferable method to improve the wear resistance and LCC of WTBs. The results of this study may provide an important reference for the selection of water lubricated materials and the design of heavy load WTBs.

The absorption of moisture/water can affect the mechanical and thermal properties of polymers and polymer composites as many polymers, mainly polyamide thermoplastics, are sensitive to environmental humidity and can absorb a large amount of moisture. This paper investigates the effect of water molecules' absorption on mechanical and thermal properties of polyamide6/hexagonal boron nitride (PA6/h-BN) composites.

The PA6/h-BN composites were exposed to an open environment and water for 15 days to analyse the effect of humidity/water molecules' absorption on mechanical and thermal properties. The tensile strength, hardness and impact strength of materials were measured and compared. The scanning electron microscopy (SEM), x-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses were utilized to see the influence of water absorption on microstructure, crystallinity and glass transition temperatures.

After exposing materials to an open environment and water, the tensile strength and hardness were found to decline, while improvement in impact strength was noticed. SEM characterization revealed the formation of voids/pockets in water-immersed materials. DSC analysis revealed the loss in glass transition temperatures, and XRD analysis revealed the loss in crystallinity of water-immersed materials.

Environmental conditions vary according to the geographical areas, and it varies in many countries throughout the year. Polyamides are sensitive to the environmental humidity and can absorb a large amount of moisture from the environment. It becomes necessary to test these materials in their original working conditions, and sometimes it is mandatory to see the effects of extreme environmental conditions on a component. In this article, efforts have been made to investigate the influence of extreme humidity/water conditions on thermo-mechanical properties of PA6/h-BN composites.

The purpose of this study is to critically analyze the properties of quenched and tempered steel samples. Austenite to martensite transformation of steel is a common process in any steel industry. Water quenching is the best suited technique to convert the steel into martensitic structure. Although quenched products are very hard, yet they possess brittleness. Due to which, their industrial applications become very limited. To avoid this problem, tempering of the martensite is usually done to achieve the required combination of hardness and toughness.

The present work deals with comparative analysis of mechanical properties and microstructural behavior of quenched and tempered steel samples. For the purpose, a low carbon steel (0.2%-C) was taken under study. Quenching was done in water, and tempering was done in atmospheric air. Four different mechanical properties such as tensile strength, toughness, hardness and shear strength were analyzed on steel samples that underwent through two different above-mentioned heat treatment processes.

An improvement in all the four mechanical properties was reported after tempering the quenched products. Also, the microstructural images of quenched and tempered specimens showed a good corroboration with mechanical properties.

A significant improvement in mechanical properties was reported in tempered specimens. Also, there was a strong corroboration between mechanical properties and microstructural attributes. A clear view of needle-shaped martensite and lamellar-shaped pearlite was observed in water-quenched and tempered specimens, respectively.

Acryclic copolymers from methacrylic acid‐ethyl acrylate or butylacrylate were prepared and incorporated into the castor oil alkyd structure. The neutralised product was water soluble. Water soluble hexamethoxy methyl melamine resin was prepared and used as curing agent. Several proportions of water soluble acrylic modified alkyds and hexamethoxy methyl melamine resin were examined at various baking schedules. It was established that 30% of the curing agent gave most satisfactory properties after baking at 150°C for 30 minutes. It was found that ethyl acrylate modified compositions had better scratch hardness and acid resistance than those of the butyl acrylate modified composition. However, the latter had better alkali resistance. These surface coating compositions have been recommended as industrial primers.

The purpose of this paper is to assess the ground water quality and salinity issues in the fast developing coastal urban lands of two river basins of Thiruvananthapuram district, Kerala, South India.

In order to address the water quality of the basins, field sampling was conducted and the samples were analysed in the laboratory. A comparison with water quality standards was also made and the interpretations of the results were done using GIS and statistical tools.

The values of conductivity, chlorides and salinity show that the coastal areas of Neyyar and Karamana basins are severely affected by salinity intrusion in addition to the pollution problems. More than 90 per cent of the samples are with hardness lower than 100 mg/l. About 70 per cent of the study area is with calcium concentrations lower than 25 mg/l. The content of sulphate and magnesium in Poovar and Poonthura coastal stretches is found to be higher compared to other regions.

Since not much work has been published from the study area on these aspects, the hydrochemical characterization is a very important in deciphering the quality of ground water for its proper management. The water quality evaluation and salinity intrusion studies are very important for the future planning and development of this area.