Henry to Jim, 11 October 1963

Professional correspondenc

Applying the mastery learning model in a wildlife recreation planning and management class

Wildland Recreation Planning and Management is a 400 level course taken by Wildland Recreation majors (B.S. in Forestry) in the spring semester of their Junior year prior to their summer internship. Due to the number of field trips taken during the semester, the course is limited to 12 students. Generally 7-9 students are Wildland Recreation majors with the remaining students from Wildlife and Fisheries Science, Ornamental Horticulture and Landscape Design, or Liberal Arts. The course meets once a week from 12:40 to 6:30 pm although the class period varies with the use and length of field trips. The Mastery Learning approach in this class evolved out of the desire to raise the competency level of students in preparation for their internship experience and their future professional careers. In particular, the need for a mastery approach was based on the demands and expectations placed on the students by their internship experience. In their internships, students address issues and concerns associated with visitor and resource management often in presentations, conversations, and meetings with people from different backgrounds and disciplines. Essentially, the students are communicating with and educating the public and other professionals about concepts related to resource protection and visitor management

Lidar-based Obstacle Detection and Recognition for Autonomous Agricultural Vehicles

Today, agricultural vehicles are available that can drive autonomously and follow exact route plans more precisely than human operators. Combined with advancements in precision agriculture, autonomous agricultural robots can reduce manual labor, improve workflow, and optimize yield. However, as of today, human operators are still required for monitoring the environment and acting upon potential obstacles in front of the vehicle. To eliminate this need, safety must be ensured by accurate and reliable obstacle detection and avoidance systems.In this thesis, lidar-based obstacle detection and recognition in agricultural environments has been investigated. A rotating multi-beam lidar generating 3D point clouds was used for point-wise classification of agricultural scenes, while multi-modal fusion with cameras and radar was used to increase performance and robustness. Two research perception platforms were presented and used for data acquisition. The proposed methods were all evaluated on recorded datasets that represented a wide range of realistic agricultural environments and included both static and dynamic obstacles.For 3D point cloud classification, two methods were proposed for handling density variations during feature extraction. One method outperformed a frequently used generic 3D feature descriptor, whereas the other method showed promising preliminary results using deep learning on 2D range images. For multi-modal fusion, four methods were proposed for combining lidar with color camera, thermal camera, and radar. Gradual improvements in classification accuracy were seen, as spatial, temporal, and multi-modal relationships were introduced in the models. Finally, occupancy grid mapping was used to fuse and map detections globally, and runtime obstacle detection was applied on mapped detections along the vehicle path, thus simulating an actual traversal.The proposed methods serve as a first step towards full autonomy for agricultural vehicles. The study has thus shown that recent advancements in autonomous driving can be transferred to the agricultural domain, when accurate distinctions are made between obstacles and processable vegetation. Future research in the domain has further been facilitated with the release of the multi-modal obstacle dataset, FieldSAFE

Thermal and water management of evaporatively cooled fuel cell vehicles

Proton Exchange Membrane Fuel Cells (PEMFCs) present a promising alternative to the conventional internal combustion engine for automotive applications because of zero harmful exhaust emissions, fast refuelling times and possibility to be powered by hydrogen generated through renewable energy. However, several issues need to be addressed before the widespread adoption of PEMFCs, one such problem is the removal of waste heat from the fuel cell electrochemical reaction at high ambient temperatures. Automotive scale fuel cells are most commonly liquid cooled, evaporative cooling is an alternative cooling method where liquid water is added directly into the fuel cell flow channels. The liquid water evaporates within the flow channel, both cooling and humidifying the cell. The evaporated water, along with some of the product water, is then condensed from the fuel cell exhaust, stored, and re-used in cooling the fuel cell. This work produces a system level model of an evaporatively cooled fuel cell vehicle suitable for the study of water balance and heat exchanger requirements across steady state operation and transient drive cycles. Modelling results demonstrate the ability of evaporatively cooled fuel cells to self regulate temperature within a narrow region (±2°C) across a wide operating range, provided humidity is maintained within the flow channels through sufficient liquid water addition. The heat exchanger requirements to maintain a self sufficient water supply are investigated, demonstrating that overall heat exchange area can be reduced up to 40% compared to a liquid cooled system due to the presence of phase change within the vehicle radiator improving heat transfer coefficients. For evaporative cooling to remain beneficial in terms of heat exchange area, over 90% of the condensed liquid water needs to be extracted from the exhaust stream. Experimental tests are conducted to investigate the condensation of water vapour from a saturated air stream in a compact plate heat exchanger with chevron flow enhancements. Thermocouples placed within the condensing flow allow the local heat transfer coefficient to be determined and an empirical correlation obtained. The corresponding correlation is used to produce a heat exchanger model and study the influence different heat exchanger layouts have on the overall required heat transfer area for an evaporatively cooled fuel cell vehicle. A one-dimensional, non-isothermal model is also developed to study the distribution of species, current density and temperature along the flow channel of an evaporatively cooled fuel cell using different methods of liquid water addition. Results show that good performance can be achieved with cathode inlet humidities as low as 20%, although some anode liquid water addition may be required at high current densities due to increased electro-osmotic drag. It is also demonstrated that both good membrane hydration and temperature regulation can be managed by uniform addition of liquid water across the cell to maintain a target exhaust relative humidity

Builders and wanderers: How two tomboys escape gender conformity in Katherine Paterson’s Newbery-winning novels

This paper looks at the importance of tomboy characters in children’s literature, specifically focusing on Katherine Paterson’s Newbery-winning novels, Bridge to Terabithia and Jacob Have I Loved. Though much of the children’s literature arena remains dominated by “boy books,” the use of tomboy characters in literature offers an opportunity for teachers and parents to push aside the gender conventions and stereotypes that are reinforced through trite and redundant curriculum. The strong tomboy transcends masculine-feminine roles and develops identity outside of their restrictions. She is an ideal for young females working toward gender equality while allowing young males to safely explore “girl books.” A close analytical reading of each text provides numerous examples of tomboys breaking gender conventions in order to establish true identity. In both novels, the tomboys (Leslie Burke in Bridge to Terabithia; Sara Louise Bradshaw in Jacob Have I Loved) struggle with the rules of gender convention in the face of adolescence, peer pressure, love, and death. Readers of Paterson’s books easily relate to the characters, sharing in their triumphs and sorrows and learning from their experiences. If true change is to take place in society regarding gender roles, then it must begin in the classroom. Katherine Paterson’s novels and tomboy characters offer students the opportunity to push beyond gender conformity, as well as encourage them on their quest of self-identity. Such literature should be incorporated into the general Reading curriculum