Solid media order

In this chapter, two simple cases of stereomechanical collision of spheres are analyzed. The fundamentals of contact mechanics of solids are introduced to illustrate the interrelationship between the collisional forces and deformations of solids. Specifically, the general theories of stresses and strains inside a solid medium under the application of an external force are described. The intrinsic relations between the contact force and the corresponding elastic deformations of contacting bodies are discussed. In this connection, it is assumed that the deformations are processed at an infinitely small impact velocity and for an infinitely long period of contact. The normal impact of elastic bodies is modeled by the Hertzian theory [Hertz, 1881], and the oblique impact is delineated by Mindlin s theory [Mindlin, 1949]. In order to link the contact theories to collisional mechanics, it is assumed that the process of a dynamic impact of two solids can be regarded as quasi-static. This quasi-static approach is valid when the impact velocity is small compared to the speed of the elastic... 

The rise velocity of a single spherical cap bubble in an infinite liquid medium can be described by the Davies and Taylor equation [Davies and Taylor, 1950] (Problem 9.6). Experimental results indicate that the Davies and Taylor equation is valid for large bubbles (4oo > 0.02 m, in general) with bubble Reynolds numbers greater than 40, while for bubbles in fluidized beds, the bubble Reynolds numbers are typically on the order of 10 or less [Clift, 1986]. By analogy, the rise velocity of an isolated single spherical cap bubble in an infinite gas-solid medium can be expressed in terms of the volume bubble diameter by [Davidson and Harrison, 1963]... 

The swollen conidia treated with 0.5% colchicine for 7 d after auto-polyploidization were incubated in the double layer selection medium for 10 d at 28°C in order to select cellulase hyperproducers. After incubation, 35 colonies appeared on the surface of the selection medium. Those colonies were used for estimation of cellulase productivity on the solid medium. 

Kligman and Madigosky (j ) extended the work of Chaban to the case of a solid medium. Based on this, it can be shown that when only the lowest order terms in frequency of the monopole and quadrupole contributions are retained (the dipole contribution appears in the effective density), the effective modulus is... 

The adventitious roots were induced from the leaf segments cultured on MS solid medium containing 3 mg/1 NAA at 25 °C in the dark. The segments (1-2 cm) of the adventitious roots were inoculated into 100 ml flasks containing 50 ml MS liquid medium with the same auxin condition as root induction and cultured at 25 °C in the dark on a rotary shaker (100 rpm). The roots were subcultured at 8-10 week intervals in order to obtain sufficient materials for experiments. The roots thus obtained were inoculated into 50 ml liquid media containing various concentrations... 

The sohd-state fermentation for cellulase production is an aerobic process therefore, aeration is necessary for cell growth and cellulase formation. In addition, aeration is important in order to maintain humidity, to remove gaseous metabolites, such as COj, as well as to remove the heat of metabolism [42,43]. In a large-scale solid-state fermentor, aeration is so important that it must be controlled carefully. The aeration method and the flow rate as well as the temperature and humidity of the air supply must be regulated to avoid sudden changes in temperature and water activity of the solid medium [29,31]. 

In order to avoid over disturbing the solid medium and to prevent inhibitory effect on the growth of microbes, Ryoo et al. [75] developed a new reactor, i.e. the rocking drum reactor. As shown in Fig. 9, the reactor is in slow rocking motion. During the fermentation process, the solid substrate is gently rocked so that the air supply and humidity can be uniformly distributed. A computer-con-... 

For antimicrobial assays, there are several common methods employed. Due to its ease of operation, the most common method used is the disk diffusion method, which involves the application of a material onto a filter paper disk, and then the disk is placed onto solid medium previously seeded with the test microorganism of interest. Sometimes, the sample is dissolved in an appropriate solvent before application onto the paper disk. This method is very common in the evaluation of antibiotics and is the method adopted by the National Committee for Clinical Laboratory Standards (NCCLS). The method depends on the aqueous solubility of the antibiotics in order to facilitate diffusion through the solid medium. Essentials oils, however, are generally hydrophobic, do not readily diffuse through an aqueous medium and, therefore, the prevalence of false negatives or reduced activity might then be anticipated. 

For simple detection of contamination, the sample is cultured in wort or beer at 25 C (77°F) or 37°C (99 F) to discover whether a growth of microorganisms occurs. It is valuable in many situations however to get an indication of numbers of organisms and therefore it is preferable to plate the sample on to a solid medium at an appropriate known dilution in order to count the... 

Different veimicuhte media were studied in order to determine the parameters of an inert solid medium which could simulate the degradahon of a polymer in compost [3]. Five different vermiculite media have been tested according to type of activahon and the amount of inoculum used. The mineralizahon curves obtained for simulation tests have been compared with the mineralization curve of starch biodegradahon in compost. 

Catalytic cracking is a key refining process along with catalytic reforming and alkylation for the production of gasoline. Operating at low pressure and in the gas phase, it uses the catalyst as a solid heat transfer medium. The reaction temperature is 500-540°C and residence time is on the order of one second. 

If the solvent constituting the crystallisation medium has a compara tively high boiling point, it is advisable to wash the solid with a solvent of low boiling point in order that the ultimate crystalline product may be easily dried it need hardly be added that the crystals should be insoluble or only very sparingly soluble in the volatile solvent. The new solvent must be completely miscible with the first, and should not be applied until the crystals have been washed at least once with the original solvent. 

Diffusion within the largest cavities of a porous medium is assumed to be similar to ordinary or bulk diffusion except that it is hindered by the pore walls (see Eq. 5-236). The tortuosity T that expresses this hindrance has been estimated from geometric arguments. Unfortunately, measured values are often an order of magnitude greater than those estimates. Thus, the effective diffusivity D f (and hence t) is normally determined by comparing a diffusion model to experimental measurements. The normal range of tortuosities for sihca gel, alumina, and other porous solids is 2 < T < 6, but for activated carbon, 5 < T < 65. 

Conveying systems normally use air as the transport medium to convey granular, crushed, or pulverized materials. Modelling the flow of pneumatic conveying and calculating its pressure loss is a problematic task. The greatest problem arises from the fact that different mass flow ratios, solid flow rate divided by the gas flow rate, imply different flow types in pneumatic conveying. Each of these flow types, which can be classified in many different ways, requires its own specific model in order to provide a concrete calculation method. 

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