The Green-Ampt (GA) infiltration model is a simplified version of the physically based full hydrodynamic model, known as the Richards equation. The simplicity and accuracy of this model facilitates for its use in many field problems, such as, infiltration computation in rainfall-runoff modelling, effluent transport in groundwater modelling studies, irrigation management studies including drainage systems etc. The numerous infiltration models based on the Green-Ampt approach have been widely investigated for their applicability in various scenarios of homogeneous soils. However, recent advances in physically based distributed rainfall-runoff modeling demands for the use of improved infiltration models for layered soils with non-uniform initial moisture conditions under varying rainfall patterns to capture the actual infiltration process that exists in nature. The difficulty that modelers are facing now-a-days includes the estimation of time of ponding and the application of the infiltration model to unsteady rainfall events occurring in heterogeneous soil conditions. The investigation in this direction exhibits that only few infiltration models can handle these situations. Hence, it is of vital importance to analyze the usefulness of different variants of the Green-Ampt infiltration models in terms of their degree of accuracy, complexity and applicability limits. This paper provides a brief review of these infiltration models to bring out their usefulness in the rainfall-runoff and irrigation modeling studies as well as the drawbacks associated with these models.

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The objective of this research is to evaluate the efficacy of an active colonoscopy training model (ACTM). Colonoscopy is a widely utilized procedure for diagnosing diseases of the lower gastrointestinal tract. Since colonoscopy is a difficult procedure to teach, as well as learn, simulators are often used to teach and practice the procedure. To make learning and assessing the procedural skills easy and interactive, an active training model was developed and evaluated. To measure the applied force and the time to complete the procedure, load cells and light detecting sensors were installed in the training model and were interfaced with a data acquisition system. The user interface was programmed in LabVIEW to record the force data and time taken to complete the procedure. Thirty medical students were recruited to perform a series of three colonoscopies on the ACTM. These students were instructed how to handle the equipment and perform the colonoscopy. The procedure was also performed by experienced endoscopists to establish a benchmark. The collected data were analyzed to determine the effectiveness of the device to (1) distinguish between the participants based on their level of expertise, and (2) to detect improvement in skill of the students with repetitive sessions with the device. The results of this research may be useful to show that the ACTM may be an effective tool to integrate in to the medical training program of medical studies. It can be possibly used for evaluating the skill sets, as well as practicing the procedure before a novice surgeon performs the procedure on a patient.