Hybrid Rocket Engine Ignition and Control

Control of a hybrid rocket engine is dependent upon a robust system capable of executing commands at precise times. In order to accomplish this, hardware systems must be in place to control the flow of a pressurized gas and provide feedback to launch site personnel. Through the use of solenoid valves and wireless transceivers, control over the thrust of a rocket can be accomplished. In order to understand this information and provide a user-friendly interface to complete this, a launch control module is used. Through the combined capabilities of the two system it becomes possible to test and launch a hybrid engine rocket in a safe and efficient manner

When the going gets rough – studying the effect of surface roughness on the adhesive abilities of tree frogs

Tree frogs need to adhere to surfaces of various roughnesses in their natural habitats; these include bark, leaves and rocks. Rough surfaces can alter the effectiveness of their toe pads, due to factors such as a change of real contact area and abrasion of the pad epithelium. Here, we tested the effect of surface roughness on the attachment abilities of the tree frog Litoria caerulea. This was done by testing shear and adhesive forces on artificial surfaces with controlled roughness, both on single toe pads and whole animal scales. It was shown that frogs can stick 2–3 times better on small scale roughnesses (3–6 µm asperities), producing higher adhesive and frictional forces, but relatively poorly on the larger scale roughnesses tested (58.5–562.5 µm asperities). Our experiments suggested that, on such surfaces, the pads secrete insufficient fluid to fill the space under the pad, leaving air pockets that would significantly reduce the Laplace pressure component of capillarity. Therefore, we measured how well the adhesive toe pad would conform to spherical asperities of known sizes using interference reflection microscopy. Based on experiments where the conformation of the pad to individual asperities was examined microscopically, our calculations indicate that the pad epithelium has a low elastic modulus, making it highly deformable

Data Distribution System (DDS) and Solar Dynamic Observatory Ground Station (SDOGS) Integration Manager

The DDS SDOGS Integration Manager (DSIM) provides translation between native control and status formats for systems within DDS and SDOGS, and the ASIST (Advanced Spacecraft Integration and System Test) control environment in the SDO MOC (Solar Dynamics Observatory Mission Operations Center). This system was created in response for a need to centralize remote monitor and control of SDO Ground Station equipments using ASIST control environment in SDO MOC, and to have configurable table definition for equipment. It provides translation of status and monitoring information from the native systems into ASIST-readable format to display on pages in the MOC. The manager is lightweight, user friendly, and efficient. It allows data trending, correlation, and storing. It allows using ASIST as common interface for remote monitor and control of heterogeneous equipments. It also provides failover capability to back up machines

A Survey of Resident Attitudes on Billing and Coding Education: An Assessment by Pediatric Training Year and Career Plans

INTRODUCTION: Billing and coding (B&C) are important aspects of medical practice that many feel are taught inadequately during residency. In addressing this deficiency, residency programs must determine when and how to teach B&C. Some programs teach through informal methods or direct their education only towards senior residents and/or certain career paths. Is this approach ideal? This study evaluated pediatric resident attitudes towards formal B&C education, by post graduate year (PGY), and career plans. METHODS: A survey was distributed to residents before and after implementation of a novel, formal curriculum teaching B&C. General linear models were calculated to look at differences over time of all residents and by PGY levels and future career plans. RESULTS: Among all residents, there was no change in the highly positive attitudes towards Learning is Important, Valuable Use of Time, or Want a Formal Curriculum. Perceived Knowledge increased significantly and Need to Know More decreased significantly. There were no differences between PGY levels or career plans with all years valuing and wanting education. PGY-3s scored higher than PGY-1s and PGY-2s with Perceived Knowledge. CONCLUSION: This study demonstrated a strong, equal amount of interest in the formal education of B&C across all residents, regardless of training year and/or career plans. Pediatric residencies should consider implementing formal education on B&C to all residents. Pediatric resident attitudes towards billing and coding education can be used to guide the curriculum

Predicting Workflow Task Execution Time in the Cloud using A Two-Stage Machine Learning Approach

Many techniques such as scheduling and resource provisioning rely on performance prediction of workflow tasks for varying input data. However, such estimates are difficult to generate in the cloud. This paper introduces a novel two-stage machine learning approach for predicting workflow task execution times for varying input data in the cloud. In order to achieve high accuracy predictions, our approach relies on parameters reflecting runtime information and two stages of predictions. Empirical results for four real world workflow applications and several commercial cloud providers demonstrate that our approach outperforms existing prediction methods. In our experiments, our approach respectively achieves a best-case and worst-case estimation error of 1.6% and 12.2%, while existing methods achieved errors beyond 20% (for some cases even over 50%) in more than 75% of the evaluated workflow tasks. In addition, we show that the models predicted by our approach for a specific cloud can be ported with low effort to new clouds with low errors by requiring only a small number of executions

Volunteer Motivation and Retention in a Nonprofit Organization

This study examines the functional motivation to volunteerism behavior and hierar-chical leisure to constraint of individuals volunteering in a public service education non-profit organization. The study of motivation is grounded by the Public Service Motivation Framework and Volunteer Functional Motivation Framework, and the study of restriction of leisure activity is understood through the Hierarchical Model to Leisure Constraint Framework. The participants in our study are volunteers who actively provided service at a local public service education nonprofit organization during the period of our study. In our study, participants identified that they are functionally motivated by the values when engaging in volunteer behavior and volunteers are likely to be restricted by structural constraints to leisure when volunteering in a public service nonprofit organization