System Identification of Conveyor Belt Microwave Drying Process of Polymer Foams Using Electrical Capacitance Tomography

The microwave drying process has a wide application in industry, including drying polymer foams after the impregnation process for sealings in the construction industry. The objective of the drying process is to reach a certain moisture in the foam by adjusting the power levels of the microwave sources. A moisture controller can be designed to achieve this goal; however, a process model is required to design model-based controllers. Since complex physics governs the microwave drying process, system identification tools are employed in this paper to exploit the process input and output information and find a simplified yet accurate model of the process. The moisture content of the foam that is the process output is measured using a designed electrical capacitance tomography (ECT) sensor. The ECT sensor estimates the 2D permittivity distribution of moving foams, which correlates with the foam moisture. Experiments are conducted to collect the ECT measurements while giving different inputs to the microwave sources. A state-space model is estimated using one of the collected datasets and is validated using the other datasets. The comparison between the model response and the actual measurements shows that the model is accurate enough to design a controller for the microwave drying process.

Medical certificate education: controlled study between lectures and flipped classroom

BACKGROUND

Finnish permanent residents are covered by social security insurance administered by the Social Insurance Institution of Finland. The procedure of insurance is initiated with medical certificate written by the treating doctor. Thus, the doctor must have certificate writing skills accompanied with the knowledge of the content and goals for insurance. Quality certificates are important part of doctors' professional skills worldwide and most effective teaching methods for learning these should be investigated.

METHODS

Medical certificate data were collected from two independent courses of fourth-year student taught in autumn 2015 (N = 141) and 2016 (N = 142) in the medical faculty of the University of Eastern Finland. A random sample of 40 students per course was drawn for the analysis. All certificates were analyzed as one sample. This was done to obtain reliable results with internal control group on the differences between two teaching methods, the traditional approach and the flipped classroom (FC) approach, in 2015 and 2016, respectively. The medical certificates were evaluated and scored with a rubric (range: - 4.00-14.25) by two independent experienced specialists.

RESULTS

Compared to students in the traditional classroom, students involved in the FC received significantly higher scores in all relevant sections of the assessed certificates. The mean of the total scores was 8.87 (SD = 1.70) for the traditional group and 10.97 (SD = 1.25) for the FC group. Based on the common language effect size, a randomly selected student from the FC group had an 85% probability of receiving a higher total score than a student from the traditional group.

CONCLUSION

In this study, the FC approach resulted in a statistical significant improvement in the content and technical quality of the certificates. The results suggest that the FC approach can be applied in the teaching of medical certificate writing.