Tightly coupled work processes

The study of patient safety is the study of complexity. The study of complexity invites us to understand key concepts that can be applied to patient safety. Basic concepts from the fleld of patient safety are sharp and blunt end active and latent failure the Swiss Cheese Model of Accident Causation slips, lapses, and mistakes and hindsight bias and the fundamental attribution error. Key concepts from organizational analysis, such as normalization of deviance, diffusion of responsibility, tightly coupled work processes, and sensemaking, introduce practical lessons from high-reliability organizations. Application of specific lessons to health care are explored in Chapter Five. 

Simultaneous autonomy and interdependence. Tightly coupled work processes frequently create situations in which individuals, although socialized to be independent operators, must rely on each other if they are to execute tasks successfully. 

Meakin and Jesson (48) used the Bloch equations in part of their work on the computer simulation of multiple-pulse experiments. They find that this approach is efficient for the effect upon the magnetization vector of any sequence of pulses and delays in weakly coupled spin systems. However, relaxation processes and tightly coupled spin systems cannot be dealt with satisfactorily in this way and require the use of the density matrix. 

Under normal conditions, the processes shown in Figure 3-2 are tightly coupled, so that the oxidation of metabolic fuels is controlled by the availability of ADI which, in turn is controlled by the rate at which ATP is being utilized in performing physical and chemical work. Work output, or energy expenditure, thus controls the rate at which metabolic fuels are oxidized, and hence the amount of food that must be eaten to meet energy requirements. As discussed in section 5.3.1, metabolic fuels in excess of immediate requirements are stored as reserves of glycogen in muscle and liver and as fat in adipose tissue. 

The minimum vapor flow for the entire thermally coupled system is flat over a wide range of P Pp < P < Pr. This is the reason why dividing wall columns usually work well without tight coutrol of the vapor or liquid spht betweeu both sides of the partitiou. The optimally designed fully thermally coupled system should operate with a fractional recovery of B in the top product of the prefractionator placed somewhere between points P and R. The transition spht P is located at one end of the optimal section PR, and it is not a recommended design point for normal operation because process disturbances may move the operating point outside the optimal section PR shown in Fig. 13-70. 

The main drawback of the CVI techniques is the long processing time of infiltration, normally in the range of a hundred hours. This is coupled with a very slow rate of deposition associated with a relatively low conversion efficiency of the precursor. To address this deficiency new manufacturing approaches have been explored to develop rapid infiltration techniques and so far most of these attempts remain as research work being investigated in laboratories. Another potential problem is that CVI composites exhibit some residual open porosity. This would be a drawback for applications where gas or liquid tightness is strictly required. 

---