Endurance testing of downstream cathodes on a low-power MPD thruster

A low-power MPD thruster with downstream cathode was tested for endurance with a series of hollow cathode designs. Failure modes and failure mechanisms were identified. A new hollow cathode (with rod inserts) has emerged which shows promise for long life. The downstream positioning of the cathode was also changed from an on-axis location to an off-axis location. Data are presented for a 1332-hour life test of this new hollow cathode located at the new off-axis location. Xenon propellant was used

The Turbulence Power Spectrum in Optically Thick Interstellar Clouds

The Fourier power spectrum is one of the most widely used statistical tools to analyze the nature of magnetohydrodynamic turbulence in the interstellar medium. Lazarian & Pogosyan (2004) predicted that the spectral slope should saturate to -3 for an optically thick medium and many observations exist in support of their prediction. However, there have not been any numerical studies to-date testing these results. We analyze the spatial power spectrum of MHD simulations with a wide range of sonic and Alfv\'enic Mach numbers, which include radiative transfer effects of the $^{13}$CO transition. We confirm numerically the predictions of Lazarian & Pogosyan (2004) that the spectral slope of line intensity maps of an optically thick medium saturates to -3. Furthermore, for very optically thin supersonic CO gas, where the density or CO abundance values are too low to excite emission in all but the densest shock compressed gas, we find that the spectral slope is shallower than expected from the column density. Finally, we find that mixed optically thin/thick CO gas, which has average optical depths on order of unity, shows mixed behavior: for super-Alfv\'enic turbulence, the integrated intensity power spectral slopes generally follow the same trend with sonic Mach number as the true column density power spectrum slopes. However, for sub-Alfv\'enic turbulence the spectral slopes are steeper with values near -3 which are similar to the very optically thick regime.Comment: accepted to Ap

Hierarchical Structure of Magnetohydrodynamic Turbulence In Position-Position-Velocity Space

Magnetohydrodynamic turbulence is able to create hierarchical structures in the interstellar medium that are correlated on a wide range of scales via the energy cascade. We use hierarchical tree diagrams known as dendrograms to characterize structures in synthetic Position-Position-Velocity (PPV) emission cubes of optically thin isothermal magnetohydrodynamic turbulence. We show that the structures and degree of hierarchy observed in PPV space are related to the physics of the gas, i.e. self-gravity and the global sonic and Alfvenic Mach number. Simulations with higher Alfvenic Mach number, self-gravity and supersonic flows display enhanced hierarchical structure. We observed a strong sonic and Alfvenic dependency when we apply the the statistical moments (i.e. mean, variance, skewness, kurtosis) to the dendrogram distribution. Larger magnetic field and sonic Mach number correspond to larger values of the moments. Application of the dendrogram to 3D density cubes, also known as Position-Position-Position cubes (PPP), reveals that the dominant emission contours in PPP and PPV are related for supersonic gas but not for subsonic. We also explore the effects of smoothing, thermal broadening and velocity resolution on the dendrograms in order to make our study more applicable to observational data. These results all point to hierarchical tree diagrams as being a promising additional tool for studying ISM turbulence and star forming regions in the direction of obtaining information on the degree of self-gravity, the Mach numbers and the complicated relationship between PPV and PPP.Comment: submitted to Ap

Eating Behavior of Obese and Nonobese Retarded Adults

An obese group and a nonobese group of moderately mentally retarded adults were identified through use of body weight and tricep skinfold thickness measures. Subjects were observed individually in a sheltered workshop cafeteria during their normal lunch period. A variety of eating behavior measureswere obtained. Results indicated that the obese retarded subjects did not differ from their nonobese peers in eating rate, total meal time, or caloric intake. Large variability was observed in the measures for both groups. Implications of these data for behavioral treatments of obesity and the need for alternative explanations of an obese condition were discussed

Obesity of Mentally Retarded Individuals: Prevalence, Characteristics, and Intervention

Research on the prevalence, characteristics, and treatment of obesity of mentally retarded individuals within the context of research findings with the obese nonretarded population was selectively reviewed. According to the available literature, obesity is a prevalent problem in the retarded population, and there is a greater incidence among females than males. The literature also suggests that obese retarded subjects as a group can be distinguished from their nonobese peers by their physical condition, but not by their eating style or personality characteristics. Behavioral self-control strategies have been found to be effective in producing weight loss in obese retarded children and adults. Further research is needed to reduce the high interindividual variability observed in treatment outcome studies and to address problems of long-term maintenance of weight loss

Community Leadership Experience Guide & Booklet

Tamara BauerDuring the fall semester of 2018 and spring semesters of both 2018 and 2019, I served as the Community Leadership Experience (CLE) student coordinator for LEAD 212: Introduction to Leadership Concepts. My role in this position was to create a tangible guide and booklet to create a meaningful and purposeful learning experience for over 600 first-semester freshmen. Through research, collaboration with my faculty supervisor, and reflection, I successfully consolidated all information regarding the CLE into an intentionally designed Cats 4 Cans Best Practices Booklet and CLE Guide for students to utilize throughout their experience. Attached are both the booklet and guide for review. Within both documents are clean and simplistic designs meant to improve upon the reader’s experience as they make their way through the CLE. The Cats 4 Cans Best Practices Booklet includes each step of the project’s process, from outlining the history and purpose behind Cats 4 Cans, to providing students with resources to continue to make progress on food insecurity at K-State, in the Manhattan community, and beyond. The purpose of the CLE Guide is to provide students with a clear idea of the CLE’s guidelines and expectations. It focuses on not only the logistics behind the CLE, but also describes the issue of food insecurity and how the Staley School utilizes appreciative inquiry in order to create a powerful learning experience for each learning community (10-12 students) in LEAD 212. In the fall of 2018, the Cats 4 Cans Best Practices Booklet was introduced to all LEAD 212 sections for them to use as a resource throughout the semester. In comparing teaching evaluations between the fall of 2017 and 2018, we concluded the booklet was a success due to both qualitative and quantitative results describing students’ overall satisfaction with the CLE. Moving forward, we hope to continue making progress on improving upon the CLE for first-semester freshmen by further analyzing these results and making adjustments to both the booklet and guide as necessary. My experience working with LEAD 212 students and my faculty advisor has given me a deeper understanding of structuring curriculum, intentionally designing and organizing documents to better suit students, and ultimately helped me discover the next step I want to take in my future career; higher education