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The main objective of the research was to understand hemp processing at different stages through numerical simulations. Processing of hemp materials involves breaking the hemp into different sizes of particles and separating those particles into fractions of different sizes. Numerical models were developed using the discrete element method (DEM) to simulate hemp processing using a hammermill and separations of different hemp particles using a 3D vibratory screen-type separator. The models were implemented using a commercial DE code, the Particle Flow Code in Three Dimension (PFC3D). In the models, virtual hemp, hemp fibre and core were defined using clusters of PFC3D basic spherical particles which are connected by the PFC3D parallel bonds. The microproperties (e.g. particle stiffness and friction coefficient, and bond stiffness and strength) of these particles were calibrated. For calibrations, virtual tests were performed using PFC3D for hemp stem, fibre, and core. Those virtual tests included direct shear tests of fibre and core particles, tensile tests of fibre, and compression tests of hemp stems. The microproperties of these particles were calibrated through comparing results from the virtual tests with results from laboratory tests or literature data. Those calibrated particle microproperties were used in the PFC3D models developed for simulating the hammermill for hemp processing and the 3D vibratory separator for particle separation. These two machines were constructed using various PFC3D walls and lines, and had the main features and operational conditions as the real machines. The hammermill model was able to predict the power requirement of hammermill and particle dynamic behaviours (kinetic and strain energies) within the hammermill. The separator model was capable of predicting the separation efficiency of the 3D vibratory separator for separations of different hemp particle mixtures. The behaviour of the models reflected the real behaviour observed experimentally. The model results were reasonably good as compared with literature data and the test results. The models developed have the potential to simulate many other dynamic attributes of hemp particles with the machines. This study has laid a solid foundation for future studies of biomaterial-machine interactions using the DEM.

The present study examined the effectiveness of a self-instructional package for teaching discrete-trials teaching (DTT) to Applied Behaviour Analysis tutors at the St.Amant Applied Behaviour Analysis Program for Children with Autism. A modified multiple- baseline design across participants was used, and replicated six times. An AB design was used for one participant. The training package include a self-instructional manual, video demonstrations, and self-practice. Participants required an average of 3 hours and 56 minutes to master the manual. Eleven of the 13 participants achieved the mastery criterion during the post-training assessment. Mean DTT accuracy increased from 46.2% to 85.5% (a statistically significant increase). One tutor participated in a generalization phase with a child with autism, and their DTT accuracy averaged 80.1%. The results suggest that the self-instructional package appears to be an effective tool for teaching newly-hired tutors to conduct DTT.

The state-based approach plays an important role in modeling and control of Discrete-Event Systems (DES). Based on previous work, state feedback control of DES with nonblocking is thoroughly investigated; a general construction method for memory and the corresponding predicate is also specified. Two examples are provided in illustration. Also presented is state-based control of DES with observational abstraction. Based on the existing idea of quasi-congruence, quasi-observer, as a kind of observational abstraction, is developed; its advantages and limitations are discussed by means of simple examples. Imposing an observational partition on the state set also leads to observational abstraction. On this basis, the state-feedback controller design is introduced; in particular, the notion of high and low modeling levels for DES is proposed, based on which reachability and controllability are further discussed and compared. Finally, two simple applications are provided to show the advantage of observational partition in DES analysis and control.

The state-based approach plays an important role in modeling and control of Discrete-Event Systems (DES). Based on previous work, state feedback control of DES with nonblocking is thoroughly investigated; a general construction method for memory and the corresponding predicate is also specified. Two examples are provided in illustration. Also presented is state-based control of DES with observational abstraction. Based on the existing idea of quasi-congruence, quasi-observer, as a kind of observational abstraction, is developed; its advantages and limitations are discussed by means of simple examples. Imposing an observational partition on the state set also leads to observational abstraction. On this basis, the state-feedback controller design is introduced; in particular, the notion of high and low modeling levels for DES is proposed, based on which reachability and controllability are further discussed and compared. Finally, two simple applications are provided to show the advantage of observational partition in DES analysis and control.

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