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The writer reviews the effect of temperature on insulating materials, abstracting from the 1913 Steinmetz and Lamme report, and the 1905 British Engineering Standards Committee tests. Then he gives surveys of low-tension cables in large distributing systems, and special tests on cables including sheath cracking, high temperature tests, effect of bending on cables heated at high temperatures, distillation of cable compounds, ambient temperatures in subway ducts as affected by thermal conductivity of concrete, amount of moisture in soil, different arrangements of ducts and load factors at which the cables are operated. From this review, conclusions are derived that the permissible operating temperatures are to be a function of the load factors at which the cables operate. The writer recommends 105 deg. cent., 95 deg. cent. and 90 deg. cent. for load factors of 33 per cent, 50 per cent, and over 66 per cent, respectively.

Examination of oil vapours emitted from an oil-sealed rotary pump using gas–liquid chromatography and mass spectrometry showed their molecular weight was significantly less than the average value of the parent oil. It was suspected that the predominantly low molecular weight of the vapour was due to the evolution of inherent light fractions in the oil and to cracking products resulting from friction processes in the pump. To separate these effects small amounts of lubricants were subjected to controlled frictional working conditions under vacuum. The emitted vapour was analysed by a rapid scan mass spectrometer and the residual fluid examined for changes in composition by gas–liquid chromatography.

In a number of applications for polyethylene, particularly cable sheaths and cosmetic containers, it has been found that under certain conditions failure of the polyethylene results in a cracking of the plastic. Considerable information is available to show that in an unstressed condition polyethylene is highly resistant to a wide variety of chemical environments such as alcohols, soaps, and fatty oils. However, when polyethy lene is exposed to these environments under polyaxial stress it fails by cracking.

During the last decade considerable progress has been made in our understanding of the contact between solid surfaces. Earlier work emphasized the plastic deformation and more recent work the elastic deformation of the surface asperities. However, when sliding occurs combined normal and tangential stresses in the contact zone greatly enhance the plastic régime. Broadly speaking, recent work supports the earlier view that friction is attributable to adhesion at the points of real contact and to the ploughing or tearing of one surface by asperities on the other. In high vacuum the surface films normally present can be removed either by heating or by repeated rubbing. As a result the adhesion, friction and wear can rise to very high values. However, even under very clean conditions some metallic pairs appear to show relatively weak adhesion. With non-metals similar processes occur but with brittle solids they are complicated by surface and sub-surface cracking. Here crystal orientation can be very important. With polymeric solids, where strength properties are rate and temperature dependent, marked variations in friction with speed and temperature are often observed. The more rigid the polymer the smaller the effect. In the field as a whole little work has been carried out on the interaction between the adhesion and the ploughing mechanisms. In the field of lubrication it is now apparent that a considerable amount of what was formerly termed boundary lubrication was probably elastohydrodynamic. However, recent studies show that elastohydrodynamic films can operate under more severe conditions if small quantities of surfactants are added. These do not affect the viscous properties of the lubricant but form protective surface films of molecular dimensions. During the last decade little work has been carried out on the formation, structure and strength properties of these boundary films. It remains an area of great importance.

A listing is presented of sixteen recent papers and reports which deal with stress-corrosion cracking studies of titanium and titanium alloys. The compilation is limited to cracking phenomena in aqueous solutions at or near room temperature. A brief summary of the important aspects of each report is included.

A statewide condition survey of continuously reinforced concrete (CRC) pavements was conducted in Indiana in 1972. The survey was statistically designed and the resulting data were analyzed by using a weighted least squares analysis of variance procedure. The results of the survey were used to evaluate the effects of subbase and subgrade type, the methods of paving, steel placement and steel fabrication, concrete slump and traffic on CRC pavement performance. The measure of performance was extent of failures, parallel cracks with less than 30 in. (76 cm) crack spacing, random cracks, spalled cracks and edge pumping. The results of the statistical analysis show that subbase type, the methods of steel placement and steel fabrication, concrete slump and traffic significantly influence CRC pavement performance. Gravel subbases showed poorer performance than crushed stone and bituminous stabilized subbases. Better performance was indicated where deformed wire fabric or loose bars were used as compared with the use of tied bar mats. Depressed steel resulted in superior performance than using steel preset on chairs. The data showed little difference between performance of pavements that were slipformed as compared to those which were side formed. Relative to good performance, an optimum range of concrete slump between 2.0 to 2.5 in. (5.0 to 6.5 cm) was indicated. It was further noted that distress of CRC pavements is associated with traffic. Most of the pumping was observed on pavements with gravel subbases though some pumping was also indicated where bituminous stabilized or crushed stone subbases were used.

This paper reviews the literature relating to the effect of temperature on the life of class A insulation. It presents test data on aging of built-up samples 100 mils thick, of varnished cloth, both black and yellow, over the temperature range 105 to 200 degrees centigrade. The effect of temperature on the insulation was measured by three different methods — physical condition by visual observation, bending of the insulation to produce cracking, and the lowering of the breakdown voltage of samples which had been immersed in water. The final results are given in the form of temperature-time curves for several degrees of deterioration as measured by each of the tests.

A brief discussion of the theory of humidity drying is followed by a description of the construction and operation of a five room dryer installed above a tunnel kiln and supplied with automatic temp. and humidity control and air circulation. As compared with the older system having controlled air circulation only, the new dryer has been found to have the following advantages: (1) Reduced steam consumption; (2) 50% reduction in floor space; (3) 50% reduction in drying time; (4) Reduction in labor costs owing to elimination of a second handling of incompletely dried pieces; (5) Reduced losses from cracking and warping.

1. A study has been made of the process of two-stage hydrocracking of a heavy distillate raw material, obtaining oils and fuel products. 2. It has been shown that by two-stage hydrocracking of a heavy vacuum distillate it is possible to obtain 60% of oil products (including 38% of high-specification oil) and 40% fuel products (including about 30% winter diesel fuel).

Over 2,000,000 miles of testing on tires containing Diene rubber in blends with natural rubber or SBR show conclusively the advantages of using these stocks. Important improvements in abrasion and cracking resistance, operating temperature, rolling resistance and gasoline consumption, and traction on snow should be mentioned. At the present time, all of the Diene rubber being manufactured in a pilot plant is being utilized in production of tire stocks. It is certain that this usage will be greatly expanded in the near future when the full scale plant goes on stream.

1. It has been shown that the extraction percentage of vacuum thermal gas-oil on thermal cracking plants for producing carbon black feedstock can be approximately doubled. 2. The vacuum thermal gas-oil produced has physical and chemical properties completely in accordance with the technical specification, and in certain characteristics is superior to standard thermal gas-oil.

1. The results of laboratory studies on the catalytic hydrocracking of naphtha distillates were confirmed by tests on a commercial unit. 2. The resulting iso-component consisted mainly of C5 and C6 isoparaffins, and had a motor-method octane number of 84–86. 3. The C7+ cut, used as a feedstock for catalytic reforming, proved to be somewhat better in quality than hydrotreated straight-run naphtha. 4. Feasibility has been confirmed for producing AI-93 gasoline by blending the iso-component with severe-regime reformer naphtha, without the use of ethyl fluid, alkylate, or isomerizate, as well as producing AI-93 gasoline by blending the iso-component with mild-regime reformer naphtha and adding 0.82 g TEL/kg. 5. Stable operation of the catalyst has been demonstrated in an extended commercial run.

1. The possibility has been shown of effectively processing residual crude by the hydrocracking method, using a three-phase fluidized bed, through a continuous, extended pilot plant run; the yield of coke on balance was not over 0.2% on fresh crude. 2. In hydrocracking Aral residual oil, depending on the demands in fuel, one may obtain in winter 93% (based on the residual oil) of low-viscosity boiler fuel having a 1% sulfur content; and, in summer, up to 50% of a diesel fuel fraction plus 38% of low-viscosity boiler fuel having a 1.2% sulfur content. The vanadium content of the boiler fuel does not exceed 21 g/ton. 3. It has been established that it is necessary to limit the “coke” on the catalyst surface to maintain the required operating activity; this is achieved in practice by regular partial renewal of the catalyst charge in the reactor without destroying the technological regime. 4. The dynamics of the hydrogenating and splitting activity of finely-spherical aluminum-cobalt-molybdenum catalyst on changing the extent and multiplicity of catalyst regeneration has been studied. Satisfactory restoration of catalytic activity has been displayed upon a 9-fold oxidative catalyst regeneration, even when there were appreciable deposits on it, introduced into the reactor with the feed. 5. It has been established that spent catalyst from hydrocracking Aral residual oil contains an appreciable amount of vanadium (several percent).

1. The economic efficiency of the hydrocracking process at 50 atmospheres has been fully demonstrated. The most favorable technical and economic indices are obtained with a combination of hydrocracking of vacuum gas oil and catalytic cracking of the hydrocracking residue. The hydrocracking residue can also be used as low-sulfur component of fuel oil or for lubricant oil production. 2. At the present stage of planning developments, the process of two-stage hydrocracking at 150 atmospheres under our conditions gives less favorable indices compared with catalytic cracking and hydrorefining of petroleum products.

1. Principal patterns in single-stage hydrocracking of heavy sulfurous distillate using aluminum-cobaltmolybdenum catalyst were studied. 2. It was shown that by changing total pressure, temperature and space velocity of charging stock feed, the yield of motor fuels and the extent of treating them for sulfur and other harmful impurities may be regulated. 3. Hydrogen-charging stock ratio in the range studied (600–1500 liters/liter) did not exert any appreciable effect on the hydrocracking process. 4. It was shown that at total pressure of 50 atm, temperature of 400–425 °C and space velocity of charging stockfeedof 1–2/hour, thorough decomposition of the chargingstockwas achieved with formation of up to 30–45% low-sulfur diesel fuel and small amounts of gas and gasoline. These conditions ensure three-month minimum operation of the catalyst without loss of activity.

Mitsubishi Petrochemical Co., Ltd. and Mitsubishi Heavy Industries Ltd. have jointly succeeded in the development of Mitsubishi Thermal Cracking Furnace (M-TCF) in which wide variety of feed stocks and high productivity for ethylene production, propylene and aromatics, are achievable.M-TCF, which has been developed from the standpoint of an ethylene manufactures, can be efficiently operated for a wide range of feed stocks from ethane to heavy gas oil in combination with Mitsubishi Transferline Heat Exchanger (M-TLX). With its high product capacity and the unique structure, the M-TCF assures an easy operation and maintenance of an otherwise troublesome cracking unit.The correlations among the properties of the feed stocks, the cracking conditions, the product distribution and the decoking intervals have been clarified from an operation of a prototype test unit for about three years with various feed stocks.Concerning the thermal cracking of gas oil fraction, it has been confirmed that high temperature and short residence time are the optimum conditions for the improvement of total yield of useful products such as ethylene, propylene, and C6-C8 aromatics.

The hydro-cracking of the purified sulfite waste liquor and the precipitated lignin by using the mixture of iron hydroxide and sulfur as catalyst, were examined.The relation between the liquefied yield or the components of liquefied oil and the reaction temperature and also between the liquefied yield or the components of liquefied oil and the alkaline concentration of sulfite waste liquor were studied.

Experiments on the drying and remoistening of raw and parboiled paddy are described. The different effects of remoistening with water or water vapour are discussed and also the effects of fast and slow drying. The absorption of liquid water causes cracking of the grain up to 15% moisture content. Above 15% there is no further cracking. On absorption, the drier the paddy the greater is the degree of cracking. Slow drying does not cause cracking but fast drying does so when the moisture content is below 15%. With fast drying, cracking is not only caused when passing the 15% point but also when drying, e.g., from 13.0 to 12.0% moisture content. The importance of temperature in causing cracking is discussed. Parboiled paddy dries faster than raw paddy, because the husk is more loosely attached in the former; raw dehusked paddy and parboiled dehusked paddy dry at approximately the same rate. These results are discussed in relation to work on other starchy seeds and particularly to Fish's recent work on sorption and desorption in potato starch. It is suggested that the changes observed in paddy can be related to the peculiar properties of starch which obtain below 15% moisture content.

A brief résumé is given of the types of deterioration which cause cracking and similar forms of deterioration in vulcanized rubber and the possible remedies. A study has been made of the development of wax bloom on rubber and some of the factors which affect this development. The waxes constituting the blooms have been examined, as has the wax in the bulk of the rubber. The protection afforded by these wax blooms against ozone attack on various base mixes with both natural and synthetic rubber has been determined, using a standard technique for the ozone exposure.

1. To develop a method for increasing the yield of diesel fuel the authors have studied an alternative process of single-stage hydrocracking, the distinctive feature being recycling of the fractions with boiling points above 350°C. 2. It is shown, in comparison with the single-stage method, that this new method reduces decomposition of the crude per run but reduces the process efficiency by 30–50%, The consumption of hydrogen is increased by a factor of 1.5 and the yield of gasoline by 3–5%. 3. An increase in pressure increases the depth of decomposition of the crude and improves the quality of the products. With an increase in pressure from 50 to 100 atm the coefficient of residue recycling is approximately halved: at 100 atm it is 2.7.

Any standard method prescribed for testing the chemical durability of glass as, for example, in the form of bottles, must be set out and subsequently applied with meticulous attention to detail. For bottles of any one composition, the alkali extracted by water can be modified by the annealing conditions and by the period and conditions of storage. Individual bottles in a set may, for these reasons, not give very closely agreeing results. Standard tests must have reference to a particular size and shape of bottle. Within the limits of time tested (5 to 6 hours), the total extraction by water is proportional to the area of surface exposed; the concentration of Na2O in the solution obtained falls off as bottle capacity increases. Besides alkali extraction, pitting and cracking, when boiled with water, and flaking must be taken into account when assessing the chemical durability. Bottles after storage and subsequent washing usually yield a smaller amount of Na2O to water than when new; on the other hand, the tendency to produce flaking is increased. Aqueous alcohol more readily leads to the production of flakes than water alone, a maximum effect being associated with the mixture containing approximately 40% by volume of alcohol. Alkali extraction, however, is greater with water than with the alcohol-water mixtures.

Specifications are given for a "superior type" or paraffinic petroleum fraction of 60 seconds viscosity SUS/100°F. with an allowable range of 56 to 62 seconds for use as a plant spray oil. The specifications are based on the response of winter eggs of the European red mite (Panonychus ulmi (Koch)) to treatment. This 60-second product is believed to combine full pesticide efficiency with minimum phytotoxic hazards and is intended for use at any season. The physical and chemical tests employed to define this petroleum composition include: viscosity SUS/100°F., API gravity, unsulfonated residue, pour point and distillation range. Because of uncertainties that exist as to how the distillation characteristics of spray oils can best be defined, typical products were analyzed under both atmospheric and reduced pressure conditions. The latter procedure avoids the problem of thermal decomposition or "cracking" and appears to give more reliable results. Consequently, ASTM method D1160 conducted at 10 mm. Hg. was adopted for the distillation test in the new specifications.

with a correlation index of 96. This laboratory sample differed from the regular-production material in having higher density, refractive index, and viscosity, and a somewhat higher carbon residue. The results of these laboratory studies were used as a basis for a commercial production method to obtain extra-heavy thermal gas oil in a thermal cracking unit, which was operated during the experimental runs without any change in the existing flow plan or current operating instructions, with only a slight adjustment of the process conditions (eliminating the feed of intermediate reflux from the accumulator, increasing the load on the light-feedstock furnace to 70 m3/h, and increasing the accumulator temperature). The physicochemical property indices of the batches of feedstock (for carbon-black production) are listed in Table 1. It will be noted that the two commercial batches of extra-heavy gas oil differ from the regular-production gas oil in having higher densities, refractive indices, and viscosities, with the carbon residue of one trial batch (batch II) being no higher than that allowed by the currently effective OST specification.

1. It has been shown that the crude processing scheme has a considerable effect on the requirement of specially produced hydrogen. Hydrogen requirement is particularly high in hydrocracking processes. 2. With increased sulfur content in the crude, the requirement of special hydrogen is higher owing to reduced production of catalytic reforming hydrogen and increased specific consumption of hydrogen for desulfurizing. 3. The quality of fresh hydrogen determines the total hydrogen consumption in the process, which may be double or more the hydrogen consumption for the reaction.

1. It has been shown that the 250–420°C fraction from the thermal cracking of semitar can be used in the production of carbon black stock by selective extraction. 2. Furfural is the most suitable extraction solvent. 3. It is recommended that the thermal-cracking residue should be used fully or partially in the production of carbon black stock.

1. The possibility of obtaining carbon-black raw material from distillate coking fractions is determined by the nature of the raw materials going into the coking. 2. Extracts from distillate fractions obtained by the coking of crude oils, cracking residues, and their mixtures with extracts from the production of oil from low-sulfur petroleums, are a high-quality raw material for the production of carbon black. Analogous products from sulfur-bearing petroleums must be subjected to hydropurification before extraction, to obtain a low-sulfur carbon-black raw material. 3. Extracts of distillate fractions from the coking of tars from Koturtepinsk and Mangyshlak petroleums cannot be used as raw materials in the carbon black industry.