Solid state switching matrix for solar electric propulsion

Solid state switching matrix for solar electric propulsio

Evaluation of the Relationship Between Size, Feeding Behavior, and Feed Efficency in Beef Cattle

Feed efficiency in cow-calf operations can be influenced by multiple environmental and physiological factors. The current study examined the association between body size (weight, frame score, and volume), linear body measurements, and feeding behavior with different measures of feed efficiency in multiparous lactating beef cows. Prediction models for dry matter intake in cows using linear body measurements were also developed. Our findings indicate that body size measurements and feeding behavior may influence measures of efficiency. The inclusion of body measurements in prediction models of intake may serve as accurate and feasible methods for estimating intake of cows on farm. The associations between the traits measured may provide insight for further producing models to measure and predict efficiency traits that are easily accessible on farm. Body measurements and feeding behavior are two traits that should be accounted for when considering efficiency and selection criteria for cow-calf operations

Oral Health in the Inka Heartland During the Late Horizon: A Tale of Two Sites

This study is a comparative dental analysis of two sites in the Inka heartland during the Late Horizon (1476-1532 CE), where residents were likely servants. Reconstructing the life histories of servant groups is critical to understanding Inka statecraft and the lived experiences of Inka subjects. Oral pathological conditions compared from two contemporaneous sites (N=34, N=65) to infer diet and activity-related stress. The first site, Salapunku, is 15km southeast of Machu Picchu and was likely an administrative outpost. The second site, Saqsahuaman, overlooks the capital of Cusco and functioned as a ceremonial center. Results identify a greater number of antemortem tooth loss and edentulous individuals at Saqsahuaman compared to Salapunku. In addition, Sacsayhuaman exhibits heavy wear that suggests a variety of habitual activity and may reflect different subsistence or economic backgrounds prior to living at the site. The results point to varied diets and activity patterns between the two sites that may reflect their differing functions

Innovative Foundation Alternative Inspired from Tree Roots

It is not easy to find a more efficient foundation system than the roots of a tree. Trees create a vast three-dimensional network of roots to support and anchor the critical above-ground trunks, leaves, and limbs. In this work, investigations are made for the feasibility of imitating such a technique and creating similar networks to support civil infrastructure, particularly those subjected to moment loads such as traffic signal posts. Some of the raised questions were: Is it feasible to have a shallow tree root-based foundation system to provide the same capacities as conventional foundation alternatives? If this is feasible: What would be the ideal depth of the Root Foundation System? How far should the roots extend to provide comparable support to a conventional deep foundation system? What diameter should the root bulb of the configuration be? How far should a vertical shaft extend into the ground? Hence, the main objective of this research is to identify and test the most effective Root Foundation System geometric configurations that can provide a similar capacity as a conventional foundation for traffic signal posts. Finite element model simulations on 54 different root-based foundation models show potential for replacing the conventional drilled shaft foundation for traffic signal posts. The conventional foundation was also modeled and produced a 0.528 mm deflection. Whereas some of the best performing root foundation models achieved 0.23 mm. By comparing the resulting deflection of the conventional foundation model to the deflection of the root foundation models, the best performing root foundation models were constructed from steel and physically tested. The root foundation models were then calibrated to predict the performance of root foundation models. Results show that the RFSs with half the length and diameter of conventional deep foundations (for traffic signal poles) were able to provide more than four times the lateral load capacity compared to the control sections. This shows that RFSs have excellent potential to replace the conventional deep foundation alternatives used to support traffic signal posts. The economic and environmental impacts due to the root-inspired foundation systems could be tremendous owing to the reductions in the material requirements

A Utah-Native Plant Can Be Used to Promote Low-Impact Landscaping

Ceanothus velutinus Douglas ex Hook. (snowbrush ceanothus) is a native evergreen species that possesses significant potential for use in urban landscapes. Ceanothus velutinus fixes nitrogen in symbiosis with nitrogen-fixing actinobacteria and plays an important soil-building role. However, it is unclear how to effectively induce nodules in C. velutinus using soil containing Frankia bacteria. The purpose of this study was to understand plant growth and nodulation of C. velutinus in different soilless substrates. Ceanothus velutinus seedlings were transplanted in cone-shaped containers with calcined clay, peat moss, or perlite and inoculated with 30 ml of native soil containing Frankia bacteria. Seedlings were grown for establishment in the first month and then harvested every 2 weeks to check for nodules. All seedlings were irrigated every other day with 80 ml of nitrogen-free nutrient solution. The results showed that nodules formed on seedlings roots in about 4 months after inoculation. Harvest time had significant impact on the shoot dry weight, root dry weight, and nodule formation of seedlings. Seedlings grown in peat moss had significantly greater shoot and root dry weight than those grown in calcined clay or perlite. However, nodulation was greater for seedlings grown in calcined clay when compared with those in peat moss. Moreover, nodulation of seedlings in perlite was not significantly different from those grown in calcined clay or peatmoss. Further investigation is needed to determine the effect of nitrogen levels on the nodulation of C. velutinus for sustainable nursery production

Traction studies of northeast corridor rail passenger service: Executive summary

The enabling legislation of 1976 for improvement of service in the Northeast corridor (NEC) requires a schedule of 2 h 40 min between Washington and New York City by 1981 and 3 h 40 min between NYC and Boston, when the electrification is completed. Various options of the NEC operation that may satisfy the legislation were investigated, particularly in terms of travel time and energy consumption. NEC operations were compared with overseas systems and practices. The emerging new technology of AC traction was also evaluated