Gantt-chart

A special type of bar chart used for providing a visual representation of the schedule of a project, bears the name of the inventor Henry L Gantt, hence Gantt Charts. In these charts the time frame of the project is represented on the horizontal axis in columns of days, months or years, whichever is appropriate, and the vertical axis has rows listing the tasks to be done during the project. Against each task a bar is drawn covering its duration. 

Reactor Emptying Product Cooling Batch Distillation 

Project progress is shown in a number of ways — for example/ by shading part of the activity bar to indicate the proportion of the activity that has been completed (e.g./ 75% shaded to represent that 75% of the participants needed for a clinical trial have been enrolled). A particularly effective way to track both project progress and to identify key activities that are 

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Simple production of bar charts or Gantt charts detailing the task time scales ... 

With time duration determined for each task of the project, the next step is to determine the earliest and latest starting times for each task. There are two commonly used methods for charting the project Gantt charts and PERT diagrams. The details of these two methods are discussed on the following pages. 

A Gantt chart is a horizontal bar chart that graphically displays the time relationship of the steps in a project. It is named after Henry Gantt, the industrial engineer who introduced the procedure in the early 1900s. A line placed on the chart in the time period when it is to be undertaken represents each step of a project. When completed, the Gantt chart shows the flow of activities in sequence as well as those that can be under way at the same time. 

To create a Gantt chart, list the steps required completing a project and estimating the time required for each step. Then list the steps down the left side of the chart and time intervals along the bottom. Draw a line across the chart for each step, starting at the planned beginning date and ending on the completion date of that step. 

When your Gantt chart is finished, you will be able to see the minimum total time for the project, the proper sequence of steps, and which steps can be under way at the same time. 

You can add to the usefulness of a Gantt chart by also charting actual progress. This is usually done by drawing a line in a different color below the original line to show... 

Gantt charts are limited in their ability to show the interdependencies of activities. In projects where the steps flow in a simple sequence of events, they can portray adequate information for project management. However, when several steps are under way at the same time and a high level of interdependency exists among the various steps, PERT diagrams are a better choice. 

PERT is an acronym for Program Evaluation and Review Technique. It is a more sophisticated form of planning than Gantt charts, and is appropriate for projects with many interactive steps. There are three components of a PERT diagram circles or other convenient, closed figures represent events arrows connecting the circles represent activities and non-activities connecting two events are shown as dotted-line arrows. (A non-activity represents a dependency between two events for which no work is required.)... 

Figure 9.12 Gantt chart for the tasks outlined in Figure9.11.

Figure 7.4-1. Gantt charts (a) non-overlapping mode, (b) overlapping mode, (c) overlapping, parallel units out-of-phase. 

Fig. 7.4-4 shows Gantt charts for a four-product, three-stage plant for which processing times are given in Table 7.4-6. At each stage (unit) the processes are arranged in the following order P1-P2-P3-P4. 

For a single-product plant the calculation of equipment sizes is straightforward. First the limiting cycle time ti is determined using Eqn. (7.4-14) or Gantt charts. The batch size is then evaluated for an assumed production capacity Q and available production time H ... 

Without making Gantts charts, it is obvious from these data that the limiting times are tz,i = 8 h and tL2= 12 h. Now, capacities of both vessels can be calculated using expression (7.4-52). For vessel 1 ... 

The. sequencing is not known a priori. The Gantt charts in Fig. 7.4-13 illustrate the essence of sequencing. 

Figure 14.14 Gantt chart for a simple batch process.

Figure 14.23 Gantt chart for a repeated batch cycle for Example 14.2.

The Gantt chart shown in Figure 14.23 indicates that individual items of equipment have a poor utilization. To improve the equipment utilization, overlapping batches are shown in Figure 14.24. 

Figure 14.27 Gantt chart for Example 14.2 with intermediate storage.

Production schedules for batch processes can be sequential, overlapping, parallel, use intermediate storage, or use a combination of these. Such schedules can be analyzed using Gantt charts. Batch processes often produce multiple products in the same equipment and can be distinguished as flowshop or multiproduct plants. Equipment cleaning and material transfer policy have a significant effect on the production schedule. 

The values shown above the horizontal bars in the Gantt chart represent the quantity that is processed in a unit. In accordance with the formulation, Fig. 2.5 shows that the smaller the batch, the shorter the processing time in the same unit. The... 

Table 2.6 shows the values of the binary variables at different time points. It is worthy of note that all the binary variables are zero at the end of the time horizon, i.e. ps, implying that no state can be used at this point. The Gantt chart corresponding to these values of binary variables is shown in Fig. 2.8. 

Fig. 2.9 Gantt chart for the second literature example using aggregation model...

The PIS operational philosophy is novel and thus requires further explanation. When a batch operation is scheduled a Gantt chart is usually generated, such as... 

The data for the case study taken from an agrochemical manufacturing facility is given in Table 4.2. The corresponding Gantt chart is shown in Fig. 4.8. The processes given in Table 4.2 were specifically selected on the basis of a common... 

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