Sequence of events

the Corps of Engineers Final Report of Analytical Results ( Report ) was dated May 8, 2002. Relevant data from this report was transmitted to only one of the property owners, 48th Street, on or about January 14, 2003. The property owner transmitted his portion of the data to the District of Columbia Department of Health on January 23, 2003. At the partnering meeting on January 29, 2003, the District expressed concern over the delay and means of obtaining even a portion of the Report. Also, concern was expressed over the more important delay in notifying the four property owners. 

At the partnering meeting, the District noticed that the EPA s Remedial Project Manager had a completed Report dated May 8, 2002, which he also was given on January 14,2003. The District of Columbia requested a copy of this Report, which the Corps transmitted on January 31, 2003. 

TTie Report indicates that sampling was performed on February 8 and 13, 2001. The Report also states on page 2 under Summary Except as indicated in this report, all samples were prepared and analyzed within the specified holding times using the EPA-approved analytical procedures. The District commented on this Report and requested copies of all field notes, chain-of-custody forms, laboratory quality control results, and all other information included in the data packages including the original laboratory reports, hereby requested pursuant to the Department of 

Defense and District Memorandum of Agreement (DDMOA) dated May 9, 1994. 

This request was necessary due to the unusual nature of the timeline. A delay of a year and three months from sample collection to validated results is unusual, even for the AUES. Another delay of eight more months until the regulators and at least one property owner were notified is another inexplicable circumstance. Finally, the Report states in the first sentence, In accordance with the revised Final Work Management Plan for Follow-on Sampling for OU-4 Residential Lots, Amendment 2 (Parsons, April 2001), Parsons (a leading environmental remediation firm) collected soil samples from four OU-4 residences to assess for the presence of the American University Experiment Station (AUES) list of chemicals. The District must know how samples collected in February 2001 could be in accordance with a plan amended in April 2001. 

Signal transduction in response to chemoattractants Binding of a chemoattractant, say aspartate, to the receptor (Tar in the case of aspartate), results in subtle conformational changes of Tar with a consequent rearrangement of most, if not all, of the constituents of the receptor supramolecular complex. This rearrangement, which possibly involves stronger packing of the receptors [437], is sensed by the 

Such an additional mechanism may be provided by modulation of the interreceptor interactions within the supramolecular complexes. 

Radical chain polymerization is a chain reaction consisting of a sequence of three steps— initiation, propagation, and termination. The initiation step is considered to involve two 

The radical R- is often referred to as an initiator radical or primary radical to distinguish it from the the chain-initiating species (Mi-). 

Propagation consists of the growth of Mp by the successive additions of large numbers (hundreds and perhaps thousands) of monomer molecules according to Eq. 3-2. Each addition creates a new radical that has the same identity as the one previously, except that it is larger by one monomer unit. The successive additions may be represented by 

At some point, the propagating polymer chain stops growing and terminates. Termination with the annihilation of the radical centers occurs by bimolecular reaction between radicals. Two radicals react with each other by combination (coupling) or, more rarely, by 

Termination can also occur by a combination of coupling and disproportionation. The two different modes of termination can be represented in general terms by 

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Finally, it is worth remembering the sequence of events which occur during hydrocarbon accumulation. Initially, the pores in the structure are filled with water. As oil migrates into the structure, it displaces water downwards, and starts with the larger pore throats where lower pressures are required to curve the oil-water interface sufficiently for oil to enter the pore throats. As the process of accumulation continues the pressure difference between the oil and water phases increases above the free water level because of the density difference between the two fluids. As this happens the narrower pore throats begin to fill with oil and the smallest pore throats are the last to be filled. 

The sequence of events in a surface-catalyzed reaction comprises (1) diffusion of reactants to the surface (usually considered to be fast) (2) adsorption of the reactants on the surface (slow if activated) (3) surface diffusion of reactants to active sites (if the adsorption is mobile) (4) reaction of the adsorbed species (often rate-determining) (5) desorption of the reaction products (often slow) and (6) diffusion of the products away from the surface. Processes 1 and 6 may be rate-determining where one is dealing with a porous catalyst [197]. The situation is illustrated in Fig. XVIII-22 (see also Ref. 198 notice in the figure the variety of processes that may be present). 

Perhaps the most fascinating detail is the surface reconstruction that occurs with CO adsorption (see Refs. 311 and 312 for more general discussions of chemisorption-induced reconstructions of metal surfaces). As shown in Fig. XVI-8, for example, the Pt(lOO) bare surface reconstructs itself to a hexagonal pattern, but on CO adsorption this reconstruction is lifted [306] CO adsorption on Pd( 110) reconstructs the surface to a missing-row pattern [309]. These reconstructions are reversible and as a result, oscillatory behavior can be observed. Returning to the Pt(lOO) case, as CO is adsorbed patches of the simple 1 x 1 structure (the structure of an undistorted (100) face) form. Oxygen adsorbs on any bare 1 x 1 spots, reacts with adjacent CO to remove it as CO2, and at a certain point, the surface reverts to toe hexagonal stmcture. The presumed sequence of events is shown in Fig. XVIII-28. 

Without proper control of hazards, a sequence of events (scenario) occurs which results ia an accident. A hazard is defined as anything which could result ia an accident, ie, an unplaimed sequence of events which results ia iajury or loss of life, damage to the environment, loss of capital equipment, or loss of production or inventory. 

Mechanism of Antibacterial Action. In spite of the fact that the antibacterial activity of the amiaoglycosides has been known siace the 1940s, the mechanisms iavolved are stiU incompletely understood. Numerous reviews have appeared (eg, 108 —113) and the sequence of events seems to be as outlined below. 

For certain types of stochastic or random-variable problems, the sequence of events may be of particular importance. Statistical information about expected values or moments obtained from plant experimental data alone may not be sufficient to describe the process completely. In these cases, computet simulations with known statistical iaputs may be the only satisfactory way of providing the necessary information. These problems ate more likely to arise with discrete manufactuting systems or solids-handling systems rather than the continuous fluid-flow systems usually encountered ia chemical engineering studies. However, there ate numerous situations for such stochastic events or data ia process iadustries (7—10). 

The expected sequence of events on an alarm is basically as follows ... 

A simplified model of PC combustion includes the following sequence of events (I) on entering the furnace, a PC particle is heated rapidly, driving off the volatile components and leaving a char particle (2) the volatile components burn independently of the coal particle and (3) on completion of volatiles combustion, the remaining char particle burns. Whue this simple sequence may be generally correct, PC combustion is an extremely complex process involving many interrelated physical and chemical processes. 

Metal surfaces in a well-designed, well-operated cooling water system will establish an equilibrium with the environment by forming a coating of protective corrosion product. This covering effectively isolates the metal from the environment, thereby stifling additional corrosion. Any mechanical, chemical, or chemical and mechanical condition that affects the ability of the metal to form and maintain this protective coating can lead to metal deterioration. Erosion-corrosion is a classic example of a chemical and mechanical condition of this type. A typical sequence of events is ... 

At this point, the sequence of events eventually leading to the tube wall perforations could be established ... 

Figure 14.17 A sequence of events combining the swinging cross-bridge model of actin and myosin filament sliding with structural data of myosin with and without bound nucleotides.

This sequence of events is quite rapid. If we take typical instrumental conditions of the LIMA 2A, where the UV laser pulse duration is 5-10 ns, the fight path is "2 m, and the accelerating potential is 3 kV, then an ion arrives at the detector i n approximately 3 ps, and a ion arrives at the detector in approximately 40 ps. Since the time width of an individual signal can be as short as several tens of nanoseconds, a high speed detection and digitizing system must be employed. 

If the product of the first stage, which in practice usually also contains unreacted urea and formaldehyde, is then subjected to acid conditions at elevated temperatures the following sequence of events is observed during the second stage ... 

This information comes from a quite remarkable book. Crystal Fire The Birth of the Information Age (Riordan and Hoddeson 1997), which maps out systematically but very accessibly the events that led to the discovery of the transistor and the aftermath of that episode. I know of no better aceount of the interloeking sequence of events that led to eventual success, and of the personal characteristics of the principal participants that played such a great part in the story. 

One of the products of a nuclear power plant PSA is a list of plant responses to initiating events (accident starters) and the sequences of events that could follow. By evaluating the significance of the identified risk contributors, it is possible to identify the high-risk accident. sequences and take actions to mitigate them. 

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