Surface temperature category

For instance, all areas of south England, south of Nottingham and Stoke-on-Trend, with an altitude of 200 m or less, are considered in surface temperature category A. More information on the rest of the surface temperature categories is given in the design guide (Roberts... 

Figure 15.24 Determination of road hardness for surface temperature category A. (From Roberts, C. and Nicholls, J.C., Desigr) Guide for Road Surface Dressing. TRL Road Note RN 39, 6th Edition. Crowthorne, UK Transport Research Laboratory, 2008.)...

The road hardness category distinguished as very soft, soft, normal hard and very hard is determined from four figures developed for each surface temperature category. A sample for surface temperature category A is shown in Figure 15.24. 

The standard picture of erosion from a chemically inert surface exposed to energetic particles can be divided into two categories. The first, physical sputtering, is independent of surface temperature and proportional to the incident particle flux such that the physical sputtering rate, Rps = Yps Jin (where Yps is the temperature independent physical sputtering yield and J n is the incident particle flux). The second is the sublimation/evaporation rate, JQ, which does not depend on the flux of incident particles and strongly increases with increasing surface temperature. 

The surface hardness is measured with a test method described in BS 598-112 (2004) using a hardness probe. During the test, a weight of 35 kg is applied through a metal probe on the road surface for 10 s. After 10 s, the probe penetration depth (in millimetres) is measured, and at the same time, the surface temperature is recorded. Measurements are recommended to be conducted at surface temperatures between 15 C and 35°C. The average of 10 measurements is considered to be the representative value for the determination of road hardness category. 

Internal Control of Production Manufacturers shall prepare technical documentations that allow the conformity of a product to be assessed. In some cases a copy of these documentations shall be presented to a notified body for review. Here it is important to note that there are two categories of CE certifications, namely, CE marking with or without identification number, as shown in Fig. X/3.2.2-1. Surface temperature details are available in Table X/3.2.1-4. There is another ATEX directive (99/92/EC), which is known as the ATEX workplace directive or ATEX 137. This is meant for the duty of employees to minimize the risk from explosive atmospheres. See also Clause 3.2.3. 

Table 6.4 contains the ignition temperatures of the respective T-Classes, the permissible surface temperatures for equipment of Category 2 and 3 and some examples of assigned substances. 

Amorphous silica, ie, silicon dioxide [7631-86-9] Si02, does not have a crystalline stmcture as defined by x-ray diffraction measurements. Amorphous silica, which can be naturally occurring or synthetic, can be either surface-hydrated or anhydrous. Synthetic amorphous silica can be broadly divided into two categories of stable materials (1) vitreous silica or glass (qv), which is made by fusing quart2 at temperatures greater than approximately 1700°C (see Silica, vitreous silica), and microamorphous silica, which is discussed herein. 

The qualification of brazing procedures, brazers, or brazing operations is required in accordance with the requirements of Part QB, Sec. IX, ASME Code, except that for Category D fluid seiwice at design temperatures not over 93°C (200°F). Such qualification is at the owners option. The clearance between surfaces to be joined by brazing or soldering shall be no larger than is necessary to allow complete capillary distribution of the filler metal. 

The progress of this category of reactions is expected to depend on the composition of the materials within the phase as well as the temperature and pressure of the system. The rate of homogeneous reaction should not be affected by the shape of the container, the surface properties of the solid materials in contact with the phase, and the diffusion characteristics of the fluid. Thus the rate of reaction of component i may be expressed as... 

Low Temperature (Non Equilibrium) Plasmas The rigorous classification of plasma treatments is difficult, however, from the viewpoint of the treated surface there are three broad categories ... 

The versatility and accessibility of polyoxometalates (POMs) have led to the various applications in the fields of structural chemistry, analytical chemistry, surface science, medicine, electrochemistry, photochemistry, and catalysis. Especially, POMs have received much attention in the area of oxidation and acid catalysis [25-31]. Several categories of POMs are formed by proper selection of the starting components and by the adjustment of pH and temperature. Typical examples are shown in Figure 13.1 (i) isopolyoxometalates of the general formula, MxO> 1, produced by condensation... 

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