Point process

An eminently practical, if less physical, approach to inherent flaw-dependent fracture was proposed by Weibull (1939) in which specific characteristics of the flaws were left unspecified. Fractures activate at flaws distributed randomly throughout the body according to a Poisson point process, and the statistical mean number of active flaws n in a unit volume was assumed to increase with tensile stress a through some empirical relations such as a two-parameter power law... 

Oil- or gas-fired boilers >45 metric tons/day Kiln and clinker cooler Fugitive emission points Process equipment Process equipment Dryers, etc/... 

Move set point to measured value Action Action Omitted Set point left at original value System may operate at wrong set point. Process hazard may occur (Moderate) Noticeable change of value of variable may occur at step 1.2 Introduce check in checklist... 

The shape of a vessel determines how well it drains (Figure 53.7). If the outlet is not at the very lowest point process liquid may be left inside. This will concentrate by evaporation unless cleaned out, and it will probably become more corrosive. This also applies to horizontal pipe runs and steam or cooling coils attached to vessels. Steam heating coils that do not drain adequately collect condensate. This is very often contaminated by chloride ions, which are soon concentrated to high enough levels (10-100 ppm) to pose serious pitting and stress corrosion cracking risks for 300-series austenitic stainless steel vessels and steam coils. 

Processes and equipment should be designed to reduce the chances of mis-operation by providing tight control systems, alarms and interlocks. Sample points, process equipment drains, and pumps should be sited so that any leaks flow into the plant effluent collection system, not directly to sewers. Hold-up systems, tanks and ponds, should be provided to retain spills for treatment. Flanged joints should be kept to the minimum needed for the assembly and maintenance of equipment. 

Any compartment of the aquatic ecosystem can be represented as a particular volume containing water, particulate matter, biota, dissolved materials, etc. Loadings and exports are represented as mass fluxes across the boundaries of the volume element (processes Se, D and L). Reactive processes are treated as point processes centered within the volume. Thus, the EXAMS model takes into account both physical and chemical processes that affect the environmental fate of a particular chemical. 

Figure 2.2. DSC thermograms of n = 6 monomer illustrating melting point processing window at three stages of purification (top, crude monomer product middle, insufficiently purified monomer bottom, sufficiently purified monomer).

Manufacturing Process end points Process fault detection... 

These sub-dew point processes can increase the overall Claus plant sulfur recovery to up to 99%, as limited by equilibrium conversion and sulfur vapor pressure losses. Elf Aquitaine s Sulfreen process, Amoco s cold bed adsorption (CBA) process, and the Mineral and Chemical Resource Company (MCRC) process licensed by Delta Hudson are all variations on the cold bed sub-dew point process. 

D.L. Snyder, Random Point Processes (Wiley, New York 1975) D.R. Cox and V. Isham, Point Processes (Chapman and Hall, London 1980). 

Stubbs, J. R. and Elsdon, G. D. 1934. The examination of one thousand milks by the Hortvet freezing-point process. Analyst. 59, 146-152. 

If other kinetics represent the point process, the problem is still defined as long as Rp can be written in terms of concentrations at the adsorption site, although the solution will be more difficult. 

Fig. 1. Export kinetics of MBP anti MBP16-1 in SecB and SecB" cells. Wild-type cells (top) or cells devoid of SecB (bottom) synthesizing either wild-type preMBP (left-hand column) or export-defective preMBP16-l (right-hand column) were pulse labeled with [ S]methionine for 15 sec followed by addition of excess unlabeled methionine. Samples were removed at the indicated chase points, processed for immunoprecipitation with anti-MBP antiserum, and analyzed by SDS-PAGE. The positions of precursor (p) and mature (m) MBP are indicated by arrows. From Collier and Bassford (1989).

---