Container wall thickness determination

The WVTR through the container is determined by the container wall thickness, the permeability of the material and the difference between the external and internal relative humidity environments. Waterman et al. [99] determined the theoretical rate of water permeation through a standard 60-cc bottle when stored at 40°C/75% RH. This equated to an uptake of 1 mg of water per day. They commented that even if the product had been packed under low water vapour conditions the relative humidity conditions within the container would be equate to 50% RH within 1 day. The WVTRs (see Table 2.8) for some common packaging materials were reported by Waterman et al. [99]. 

The fluid in a rotating centrifuge exerts pressure on the walls of the bowl or basket. The minimum wall thickness required to contain this pressure load can be determined in a... 

Using the results of Problem 12-11, determine the required vessel wall thickness to contain this explosion if the vessel is made of stainless 316. 

Using the results of Problem 12-13, determine the vessel wall thickness required to contain an explosion in another vessel that is physically connected to the first vessel with a 1-in pipe. Describe why the second vessel requires a greater wall thickness. 

Determine the vessel wall thickness required to contain an explosion of 2 lb of TNT. The spherical vessel is 1.5 ft in diameter and is constructed with stainless steel 316. 

Fabrication of titania nanotube arrays via anodic oxidation of titanium foil in fluoride based solutions was first reported in 2001 by Gong and co-workers [58]. Further studies focused on precise control and extension of the nanotube morphology [21], length and pore size [22], and wall thickness [3]. Electrolyte composition plays a critical role in determining the resultant nanotube array architecture and, potentially, its chemical composition. Electrolyte composition determines both the rate of nanotube array formation, as well as the rate at which the resultant oxide is dissolved. In most cases, a fluoride ion containing electrolyte is needed for nanotube array formation. In an effort to shift the band gap of the titania... 

The plant cell is surrounded by a cell wall, which determines many features of the plant. The outer layer of the cell wall are called middle lamella because it contains heavy layer of pectin (a polygalacturonan) that serves as the glue to hold one plant cell firmly to an adjacent cell. The inner layer of the wall is cell membrane. The cell membrane is completely different from the cell wall in form, composition, and function. Whereas the wall is a rigid, relatively thick structure, the cytoplasmic membrane is thin (approximately 75 A) and flexible. The membrane is composed of protein and lipid, whereas the wall is carbohydrate in nature. The wall provides support, whereas the membrane regulates the movement of substances into and out of the cell. 

Recently Eliasson and Matousek [26, 62] demonstrated that SORS can provide a chemical signature of the internal content of opaque plastic containers. This is demonstrated in Fig. 3.11 for aspirin tablets held inside an opaque (white) plastic pharmaceutical bottle (1.3mm thick). The conventional Raman signal is overwhelmed by the Raman component originating from the container wall and is consequently ineffective in determining the contents of the bottle. In contrast, the SORS method using a scaled subtraction of two SORS spectra measured at different spatial offsets yields a clean Raman spectrum of the tablets inside the bottle. SORS has also been used in the detection of counterfeit anti-malarial tablets by Ricci et al. [63] the chemical specificity of Raman spectroscopy readily distinguished between genuine and fake tablets and identified the content of the counterfeit tablets. 

The minimum wall thickness required to support the weight of the contained acid and the roof structure is determined using the formula... 

The membrane reactor shown in Fig. 6.5 consists of a tubular shell containing a tubular porous membrane. It defines two compartments, the inner and the outer (shell) compartments. The reactants are fed into the inner compartment where the reaction takes place. We can observe that when the reactants flow along the reactor, one or more of the reaction participants can diffuse through the porous membrane to the outer side. In this case, we assume that only one participant presents a radial diffusion. This process affects the local concentration state and the reaction rate that determine the state of the main reactant conversion. The rate of reaction of the wall diffusing species is influenced by the transfer resistance of the boundary layer (1/lq.) and by the wall thickness resistance (S/Dp). 

The fluid in a rotating centrifuge exerts pressure on the walls of the bowl or basket. The minimum wall thickness required to contain this pressure load can be determined in a similar manner to that used for determining the wall thickness of a pressure vessel under internal pressure. If the bowl contains a single homogeneous liquid. Figure 13.48a, the fluid pressure is given by ... 

Beeckman and Hegedus [50] determined the intrinsic kinetics over two commercial vanadia on titania catalysts. A mathematical model was proposed to compute NO and SO2 conversions and the model was validated by experimental values. Slab-shaped cutouts of the monolith and powdered monolith material were used in a differential reactor. The cutouts contained nine channels with a length of 15 cm and with a channel opening and wall thickness of 0.60 and 0.13 cm, respectively. The SCR reaction over a 0.8 wt% V2O5 on titania catalyst was first-order in NO and zero-order in NH3. 

All design data such as pressures and temperatures are regarded as mandatory conditions that must be satisfied. Upset and transient operating conditions are sometimes governing. Eor example, the maximum design pressure and coincident temperature will determine the wall thickness of a carbon steel process vessel containing dry H2S. However, even traces of liquid water in the presence of H2S can initiate sulfide stress corrosion cracking in carbon steel. This should add the requirement of PWHT. 

Once the water transport limitations have been designed to be polymer dependent for a given container, the amount of polymer necessary to perform this task can be determined. For most containers, this implies estimating a wall thickness. For a polymer with water transport characteristics not highly dependent on environmental water activity, Labuza (27,28) has determined the design equation to be ... 

Although there are a number of materials with the desired pore structure, for instance silicone rubbers, hydrocarbon rubbers, polyesters, polycarbonates and others, their use for industrial applications is limited to polysulfones and cellulose acetates. While the latt have been used with good success for dehydration, technical gas separation relies exclusively on polysulfones which can be used up to approximately 70 °C (their melting point is around 200 °C) and at pressures between IS and 140 bar. The lowest pressure differential between the feed gas side and the permeate gas side is 3 1 and this differential pressure determines the wall thickness of the membranes. Figure 2.8 shows the design of a membrane element developed by Monsanto Company, USA and marketed by the name of Prism separator. Each of these elements or modules contains thousands of hollow fibres packed to a density of approximately 1(X) per cm. ... 

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