Hypervelocity Impact of Composite Overwrap Pressure Vessels

There is a limited amount of hypervelocity impact (HVI) data on pressurized composite overwrapped pressure vessels (COPV). In recent years, NASA has performed HVI tests to characterize impact conditions resulting in either leak or burst of the COPVs representative of spacecraft hardware. This paper reports on the results of 40 tests that have been conducted on several types of COPV configurations, pressurized by inert gas to near the vessels rated maximum expected operating pressure (MEOP). These tests were used to better understand COPV response under HVI conditions and develop ballistic limit equations (BLE) related to these tests

Honors Advising for Large Programs

This study was conducted within the Honors Program at the University of Iowa, which is the flagship public research university of the State of Iowa. Its Carnegie classification is Doctoral University with Highest Research Activity (R1), and it is a member of the Association of American Universities. Its current student population is about 21,600 undergraduates and about 9,600 graduate and professional students. This study was conducted within the Honors Program at the University of Iowa, which is the flagship public research university of the State of Iowa. Its Carnegie classification is Doctoral University with Highest Research Activity (R1), and it is a member of the Association of American Universities. Its current student population is about 21,600 undergraduates and about 9,600 graduate and professional students. Beyond using the rate of completion of the required 12 units of honors coursework within four semesters as a measure of the effectiveness of peer mentoring, we also surveyed students who had some type of peer mentoring experience as described above. To assess the effects of peer mentoring, we used nine Likert-scaled questions. (These questions are shown in Table 3.) We also asked two open-ended questions that required a written response: one question on how peer mentoring contributed to the mentee’s honors experience and another on ways to improve peer mentoring

A Satellite Assessment of Environmental Controls of Phytoplankton Community Size Structure

Phytoplankton play a key role as the base of the marine food web and a crucial component in the Earth\u27s carbon cycle. There have been a few regional studies that have utilized satellite‐estimated phytoplankton functional type products in conjunction with other environmental metrics. Here we expand to a global perspective and ask, what are the physical drivers of phytoplankton composition variability? Using a variety of satellite‐observed ocean color products and physical properties spanning 1997–2015, we characterize spatial and temporal variability in phytoplankton community size structure in relation to satellite‐based physical drivers. We consider the relationships globally and by major thermal regimes (cold and warm), dominant size distribution, and chlorophyll concentration variability. Globally, euphotic depth is the most important parameter driving phytoplankton size variability and also over the majority of the high‐latitude ocean and the central gyres. In all other regions, size variability is driven by a balance of light and mode of nutrient delivery. We investigated the relationship between size composition and chlorophyll concentration and the physical drivers through correlation analysis. Changes in size composition over time are regionally varying and explained by temporal shifts in the varying physical conditions. These changes in phytoplankton size composition and the varying underlying physical drivers will ultimately impact carbon export and food web processes in our changing ocean

Record-breaking earthquake intervals in a global catalogue and an aftershock sequence

For the purposes of this study, an interval is the elapsed time between two earthquakes in a designated region; the minimum magnitude for the earthquakes is prescribed. A record-breaking interval is one that is longer (or shorter) than preceding intervals; a starting time must be specified. We consider global earthquakes with magnitudes greater than 5.5 and show that the record-breaking intervals are well estimated by a Poissonian (random) theory. We also consider the aftershocks of the 2004 Parkfield earthquake and show that the record-breaking intervals are approximated by very different statistics. In both cases, we calculate the number of record-breaking intervals (<i>n</i><sub>rb</sub>) and the record-breaking interval durations Δ<i>t</i><sub>rb</sub> as a function of "natural time", the number of elapsed events. We also calculate the ratio of record-breaking long intervals to record-breaking short intervals as a function of time, <i>r(t)</i>, which is suggested to be sensitive to trends in noisy time series data. Our data indicate a possible precursory signal to large earthquakes that is consistent with accelerated moment release (AMR) theory

A microbiological assay for host-specific fungal polyketide toxins

Genetic analysis of biosynthetic pathways for fungal secondary metabolites depends on availability of efficient and dependable assays for the end products. Some fungal plant pathogens produce secondary metabolites called host-specific toxins. Until recently, all bioassays for these toxins required use of whole plants or plant parts (Yoder 1981 In: Toxins in Plant Disease, Durbin ed., pp. 45-78). Since host-specific toxins, by definition, affect only plants that are susceptible to the toxin-producing fungus, other plants, animals and microorganisms are not sensitive and therefore cannot be used in bioassays

Far from Home: A Qualitative Analysis of Altered Social and Familial Interactions by Students Attending College Significant Distances from Home

This study explored the necessary modifications for students’ relationships with their home contexts (social and familial) as they acclimated to college life. We specifically targeted students living over 1,000 miles from their present school setting. Thirty undergraduate students at a private Midwest university participated in this qualitative phenomenological research study through semistructured interviews. While numerous dynamics surfaced, repeated themes included feelings of homesickness, desiring to go home, weakening of peer relationships established at home, and gradual strengthening of familial relationships

Complementation of Cochliobolus heterostrophus trp- mutants produced by gene replacement

Transformation systems for most filamentous fungi are based on selection for drug resistance. This strategy is advantageous becasue wild-type strains, including isolates collected directly from the field, can be used as recipients in transformation experiements

Before you order tree seedlings

"Good planting practices include good planting stock, a well selected and properly prepared site, proper planting methods, and adequate protection and care after planting. Failure in any or all of these planting practices usually results in unsatisfactory survival or growth or even in complete failure."--First page.Carol B. Trokey and John P Slusher (The School of Natural Resources College of Agriculture), William G. Yoder (Missouri Department of Conservation)Revised 3/90/5

Mobile camera-space manipulation

The invention is a method of using computer vision to control systems consisting of a combination of holonomic and nonholonomic degrees of freedom such as a wheeled rover equipped with a robotic arm, a forklift, and earth-moving equipment such as a backhoe or a front-loader. Using vision sensors mounted on the mobile system and the manipulator, the system establishes a relationship between the internal joint configuration of the holonomic degrees of freedom of the manipulator and the appearance of features on the manipulator in the reference frames of the vision sensors. Then, the system, perhaps with the assistance of an operator, identifies the locations of the target object in the reference frames of the vision sensors. Using this target information, along with the relationship described above, the system determines a suitable trajectory for the nonholonomic degrees of freedom of the base to follow towards the target object. The system also determines a suitable pose or series of poses for the holonomic degrees of freedom of the manipulator. With additional visual samples, the system automatically updates the trajectory and final pose of the manipulator so as to allow for greater precision in the overall final position of the system