Transport time

Sample Transport Transport time, the time elapsed between sample withdrawal from the process and its introduction into the analyzer, shoiild be minimized, particiilarly if the analyzer is an automatic analyzer-controller. Any sample-transport time in the analyzer-controller loop must be treated as equivalent to process dead time in determining conventional feedback controller settings or in evaluating controller performance. Reduction in transport time usually means transporting the sample in the vapor state. 

The discrete distance option of SCREEN allows the user to input specific distances. Any number of distances (s 1 meter) can be input by the user and the maximum concentration for each distance will be calculated. The user will always be given this option whether or not the automated distance array option is used. The option is terminated by entering a distance of zero. SCREEN will accept distances out to 100 km for long-range transport estimates with the discrete distance option. However, for distances greater than 50 km, SCREEN sets the minimum 10 meter wind speed at 2 m/s to avoid unrealistic transport times. 

Introducing the values into the equation, using a minimum Kd-value of >300, gives a retention factor of >750. If this value is combined with a representative water transport time from repository to recipient (>1000 years for a distance >100 m), the transport equation indicates that it will take the plutonium >750,000 years to reach the recipient which is the water man may use. This estimate is supported by findings at the ancient natural reactor site at Oklo in Gabon (67). 

Equations A12-A14), which represent the ratio of the effective transport time with the time taken for concentration of the isotope to decrease by half. For 1, while... 

Cheung, P., Balke, S. T., and Mourey, T. H., Data interpretation for coupled molecular-weight-sensitive detectors in SEC interdetector transport time,... 

FMLs permit the release of organics and vapors via molecular diffusion by almost the same process. Transport times for organic chemicals through FMLs typically range from a few hours to a few days. 

Quandt (1962) measured the values of (CfICm - 1) at various axial positions of an air-water mixture flow in a 0.25-in. X 3-in. channel and converted the raw data to the exchange mass flux, pLV(, as shown in Figure 5-23. He also measured the film velocity Vf by injecting a pulse of dye into the liquid film and recording its transport time between two photocells. Such measured data are shown in Figure 5.24. By using the measured values for Vf, the liquid film thickness t may be calculated as... 

EXPLAIN how capacitance, resistance, and transportation time affect a control system s lag time. 

Control loops can be either stable or unstable. Instability is caused by a combination of process time lags discussed earlier (i.e., capacitance, resistance, and transport time) and inherent time lags within a control system. This results in slow response to changes in the controlled variable. Consequently, the controlled variable will continuously cycle around the setpoint value. 

If small specimens are truly immersed in a proper amount of fixative, there is no technical reason to rush them to the laboratory. For biopsies at least, longer transport times usually result in better quality. 

Repeat the calculation for a transport rate of 50 lb/min and 100 lb/min for transport times of 1 hr and 5 hr. Discuss ways to improve the safety of this situation. 

Due to stochastic demand in China, stochastic production yields in Europe and some stochastic variations in transport times between the two it was decided to support the decision between these alternatives by means of simulation. The structure of the simulation model is shown in Figure 2.2. 

Link type 13, for example, states that the start of production of the succeeding product may only be set after the production end of the pre-product. The minimum offset time mirrors a minimum transport time so that in the earliest case possible the production of the successor can start at the time of the production end of the predecessor plus minimum offset. The maximum offset equals a maximum transport time so that the production of the succeeding product can start in the latest case possible at the time of the production end of the predecessor plus maximum offset. The offset times therefore limit the time window for the production start of the successor. 

Hence, we see that this mixing time is also very small. However, this analysis implicity assumed that the pilot is located where the fuel vapor evolved. A pilot downstream would introduce an additional transport time in the process. 

One approach is to approximate the unsteady solution by a quasi-steady solution where Q(t) is a function of time and time is adjusted. This can be approximated by determining the transport time (fD) from the origin to position z by... 

Distribution planning described in subchapter 5.5 handles multi-period transportation time and transit inventories as global material flow planning. Moreover, static and dynamic inventory planning is supported. 

In order to reflect these lead times, the concept of a timestamp is introduced. Timestamp is used in computer science documenting the system time when a certain event or transaction occurs e.g. for logging events (N.N. 2007). In the context of future inventory value planning, the time-stamp marks the period, when the first raw material has reached a certain stage in the value chain network included into a specific product. In the example illustrated in fig. 57, the raw material is processed in the same period to be converted into product 1. Therefore, all four value chain steps indexed from one to four occur in the same period and have the same time-stamp one. Conversion into product 2, however, requires additional time caused by production lead times, safety inventory and/or transportation time, that the steps indexed with five and six have a time stamp of two. The timestamp reflects that the inventory value of product 2 is not based on the raw material costs from the same period but based on the raw material costs from the previous period in order to reflect the lead time. Consequently, value chain indices and timestamps are defined for all steps and can cover multiple periods reflecting that raw materials in a global complex multi-stage value chain network can take several months, until they are sold as part of a finished product to the market. 

Transportation lanes have a transportation time dTe, ee E measured in days. A transcontinental transportation lane connecting NAFTA with Asia for example can require more than 30 days of transportation time. A normed period transportation time dTn of 30 days per period is defined. The normed period transportation time represents the planning bucket month. Since sent and received transportation quantities depend on transportation time, subsets of transportation lanes depending on the transportation time dTe, e e E and the normed transportation time dTn as illustrated in table 26 are created. 

Table 26 Transportation lane index sets depending on transportation time...

The transportation time criterion is used to group transportation lanes uniquely into one of the shown three index sets. Transportation lanes with transportation time longer than 0 are additionally grouped in index set 4. Grouping of transportation lanes will be used to later distinguish different transportation cases leading to different equations to calculate transportation sent and received quantities. 

The grouping approach accepts a certain error on the monthly planning level compared to the exact operations level. On the operations level, all transportation lanes - also location-internal transfers e.g. in pipelines -have a transportation time > 0. Conceptually, it is required to make a clear cut between planning and operations and to define a planning tolerance interval e.g. 10% of the total period time - in this case 3 days -, where transportation times are set equal to 0. Otherwise, the planner always would miss 3% of volume in the same planned period due to the transportation time lag of 3 days leading to complexity in the plan. 

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