Constructing Carmichael numbers through improved subset-product algorithms

We have constructed a Carmichael number with 10,333,229,505 prime factors, and have also constructed Carmichael numbers with k prime factors for every k between 3 and 19,565,220. These computations are the product of implementations of two new algorithms for the subset product problem that exploit the non-uniform distribution of primes p with the property that p-1 divides a highly composite \Lambda.Comment: Table 1 fixed; previously the last 30 digits and number of digits were calculated incorrectl

Autonomous Satellite Recovery Vehicle (ASRV) Final Report

In collaboration with Embry-Riddle Future Space Explorers and Developers Society (ERFSEDS), we came up with the idea to build a quad-copter/sensor system that could be deployed from a rocket. The goal is to build a new chassis for the quad-copters electronic components that will allow the quad-copters arms to fold inwards to meet the required space constraints of a rocket. In addition to the critical components of the quad-copter, our design will integrate a number of other data collecting sub-systems currently being used in a weather balloon designed by Society 4 S.P.A.C.E. club members. After being jettisoned from the rocket, the sensor systems objective would be to collect atmospheric data as it descends. At the altitude of 2,000 feet the quad-copter would be programmed to deploy a parachute. Once it has reached a safe velocity the arms would extend, motors engage, and the quad would autonomously navigate to a prearranged location. Flight planning will be done using a preexisting flight planning application. Data gathered from the sensors will include pressure, temperature, humidity, wind, and video. This project will give us a better understanding of rocket propulsion systems and the effect of launch on the payload. It will also allow us to gain valuable research, data retrieval, team development and multi-club collaboration experience

Active and passive microwave measurements in Hurricane Allen

The NASA Langley Research Center analysis of the airborne microwave remote sensing measurements of Hurricane Allen obtained on August 5 and 8, 1980 is summarized. The instruments were the C-band stepped frequency microwave radiometer and the Ku-band airborne microwave scatterometer. They were carried aboard a NOAA aircraft making storm penetrations at an altitude of 3000 m and are sensitive to rain rate, surface wind speed, and surface wind vector. The wind speed is calculated from the increase in antenna brightness temperature above the estimated calm sea value. The rain rate is obtained from the difference between antenna temperature increases measured at two frequencies, and wind vector is determined from the sea surface normalized radar cross section measured at several azimuths. Comparison wind data were provided from the inertial navigation systems aboard both the C-130 aircraft at 3000 m and a second NOAA aircraft (a P-3) operating between 500 and 1500 m. Comparison rain rate data were obtained with a rain radar aboard the P-3. Evaluation of the surface winds obtained with the two microwave instruments was limited to comparisons with each other and with the flight level winds. Two important conclusions are drawn from these comparisons: (1) the radiometer is accurate when predicting flight level wind speeds and rain; and (2) the scatterometer produces well behaved and consistent wind vectors for the rain free periods

Social and temporal dynamics mediate the distribution of ecosystem service benefits from a small-scale fishery

Small-scale fisheries are important for the livelihoods and food security of millions of people in low-income countries. Sustainably managing these dynamic social-ecological systems requires understanding links between ecosystems and human well-being: the focus of ecosystem service approaches. However, in-depth exploration of how co-production and temporal dynamics shape ecosystem benefits in small-scale fisheries remain nascent. There is thus an opportunity to better investigate pathways through which small-scale fisheries support food security. To address this gap, we ask how households allocate seafood landings across different uses, depending on supply and season. Using a daily survey, we collected panel data on landings from 15 households on Atauro Island, Timor-Leste, over six 1-week periods across three seasons, representing 630 survey days and 179 fishing trips. We found households mediate the pathways through which seafood contributes to food security. Specifically, the proportion of landings eaten, sold or shared changed with the amount landed and across seasons. As landings increased, households ate a smaller proportion and sold a greater proportion. The greatest proportion of landings were sold in the preparation season, when households save money to buy staple foods. Landings were shared with family and kin, reflecting the importance of seafood for social capital and community food security. Put broadly, households shaped a dynamic and non-linear (not directly proportional) relationship between service supply and benefits. Our findings demonstrate that seasonal context and livelihood priorities shape seafood provisioning benefits in small-scale fisheries. Careful consideration of temporal scale in ecosystem service assessments is critical for sustainable management of small-scale fisheries

Fixed base simulator study of an externally blown flap STOL transport airplane during approach and landing

A fixed-base simulator study was conducted to determine the flight characteristics of a representative STOL transport having a high wing and equipped with an external-flow jet flap in combination with four high-bypass-ratio fan-jet engines during the approach and landing. Real-time digital simulation techniques were used. The computer was programed with equations of motion for six degrees of freedom and the aerodynamic inputs were based on measured wind-tunnel data. A visual display of a STOL airport was provided for simulation of the flare and touchdown characteristics. The primary piloting task was an instrument approach to a breakout at a 200-ft ceiling with a visual landing

Growing and Handling of Bacterial Cultures within a Shared Core Facility for Integrated Structural Biology Program

We have established and optimized standard operating procedures for growing and handling bacterial cultures in a shared core laboratory to support Integrative Structural Biology. The Integrative Structural Biology effort within the Biomolecular Research Center allows researchers to generate new knowledge about protein and RNA structure and function. We aim to understand how biomolecules assemble into stable structures and how structural dynamics impacts their function. Here we describe specific procedures for growing and handling bacterial cultures for overexpression and isolation of recombinant proteins, 15N/13C uniform labeling of recombinant proteins, protein isolation and purification, and analysis of protein solubility that are ideal for implementation in a shared research core laboratory that serves a multitude of diverse customers and research laboratories

Building Connections in Co-Production Environments

With the impact of the Covid-19 pandemic felt around the globe, consumers look forward to once again being able to engage in communal experiences where relationships with other customers and with service providers are integral parts of ongoing service experiences. The purpose of this study is to provide a framework for service establishments to better understand the communal approach to becoming a service co-creator, helping service providers create more meaningful relationships between their customers when customers are engaging in the service experience in a group and as an individual. We distinguish individual versus group influences that emerge as a result of this unique but growing class of service offerings. We extend knowledge in this area by uncovering the nontangible elements of a co-production experience found to deepen the customer-service provider relationship, which ultimately impacts repeat patronage. We examined these influences in two different co-production environments and subsequently laid the foundation for the need for further research in this area, with the goal of identifying common practices that can enhance co-creation across varied industries

Handling qualities of a wide-body transport airplane utilizing Pitch Active Control Systems (PACS) for relaxed static stability application

Piloted simulation studies have been conducted to evaluate the effectiveness of two pitch active control systems (PACS) on the flying qualities of a wide-body transport airplane when operating at negative static margins. These two pitch active control systems consisted of a simple 'near-term' PACS and a more complex 'advanced' PACS. Eight different flight conditions, representing the entire flight envelope, were evaluated with emphasis on the cruise flight conditions. These studies were made utilizing the Langley Visual/Motion Simulator (VMS) which has six degrees of freedom. The simulation tests indicated that (1) the flying qualities of the baseline aircraft (PACS off) for the cruise and other high-speed flight conditions were unacceptable at center-of-gravity positions aft of the neutral static stability point; (2) within the linear static stability flight envelope, the near-term PACS provided acceptable flying qualities for static stabilty margins to -3 percent; and (3) with the advanced PACS operative, the flying qualities were demonstrated to be good (satisfactory to very acceptable) for static stabilty margins to -20 percent