112 research outputs found
Tailoring Systems Engineering Processes in a Conceptual Design Environment: A Case Study at NASA Marshall Spaceflight Center's ACO
This paper provides an overview of Systems Engineering as it is applied in a conceptual design space systems department at the National Aeronautics and Space Administration (NASA) Marshall Spaceflight Center (MSFC) Advanced Concepts Office (ACO). Engineering work performed in the NASA MFSC's ACO is targeted toward the Exploratory Research and Concepts Development life cycle stages, as defined in the International Council on Systems Engineering (INCOSE) System Engineering Handbook. This paper addresses three ACO Systems Engineering tools that correspond to three INCOSE Technical Processes: Stakeholder Requirements Definition, Requirements Analysis, and Integration, as well as one Project Process Risk Management. These processes are used to facilitate, streamline, and manage systems engineering processes tailored for the earliest two life cycle stages, which is the environment in which ACO engineers work. The role of systems engineers and systems engineering as performed in ACO is explored in this paper. The need for tailoring Systems Engineering processes, tools, and products in the ever-changing engineering services ACO provides to its customers is addressed
Post Graduation Assessment Of Learning Outcomes
The objective of this work is to suggest a process for improving the assessment of educational outcomes in universities. Improved accountability and assessment has become an important direction in academic institutional research, but the underlying question –how best to accomplish this goal is an open question. A framework is first described which promotes the categorization of academic assessment. Based on this framework, a preliminary instrument was developed and piloted. The results of this study are reported and plans for future efforts are described
Influence of Nitrogen Rate and Sampling Date on Soil Analysis Values of Highbush Blueberries
Three studies were conducted on nitrogen (N) fertilization effects on soil of highbush blueberries in Arkansas. Objectives included: 1) determination of varying N rate effects on the standard soil analysis variables, 2) determination of date of soil sampling effects on soil analyses, 3) evaluation of the interactions of N rate and time of sampling, and 4) determination of changes in soil content over years. This research was done in two of the more important highbush blueberry production areas in Arkansas: the Arkansas River Valley where blueberries are grown on sandy loam soils, and northwest Arkansas where production is more common on silt loam soils. This information provides greater insight into the soil dynamics of highbush blueberry plantings in Arkansas and can be used to increase precision of fertility and other soil property recommendations provided to growers
Ewing's Sarcoma: Development of RNA Interference-Based Therapy for Advanced Disease
Ewing's sarcoma tumors are associated with chromosomal translocation between the EWS gene and the ETS transcription factor gene. These unique target sequences provide opportunity for RNA interference(i)-based therapy. A summary of RNAi mechanism and therapeutically designed products including siRNA, shRNA and bi-shRNA are described. Comparison is made between each of these approaches. Systemic RNAi-based therapy, however, requires protected delivery to the Ewing's sarcoma tumor site for activity. Delivery systems which have been most effective in preclinical and clinical testing are reviewed, followed by preclinical assessment of various silencing strategies with demonstration of effectiveness to EWS/FLI-1 target sequences. It is concluded that RNAi-based therapeutics may have testable and achievable activity in management of Ewing's sarcoma
Behaviors Viewed as Deplorable by Peers: A Different Approach to Programming to Curb Unacceptable Behaviors in Fraternities and Sororities
This article posits a different approach to social norm programming by presenting a targeted approach that centers attention on the degree to which members of a fraternity or sorority disdain excessive alcohol use, drug use, sexual assault, racism, and homophobia rather than a focus on the frequency of such behaviors of their peers. An appendix to this article provides a survey instrument for fraternity/sorority advisors to gauge the social norms of their chapters in regards to a handful of specific illicit behaviors – homophobia, racism, sexual assault, drug use, and alcohol use. While social norms interventions have met with limited success historically with fraternity and sorority members, this instrument and its proposed implementation are designed to evade the pitfalls of past fraternity/sororityfocused programs
What are the Benefits of Blogging in the Elementary Classroom?
Abstract This study examined the benefits of blogging in the elementary classroom. Research was conducted in a fourth grade classroom that used student blogging on laptop computers as a part of the writing program. Data was collected through observation, teacher and student interviews, and examination and analysis of student blogs. The findings show that blogging is highly beneficial for elementary students, resulting in increased motivation, strengthened writing skills, and engagement in an authentic activity. In order to increase student learning, teachers must motivate their students by creating authentic and purposeful learning activities that involve student engagement, communication and collaboration with one another, and technology-rich experiences that bring out of school literacies into the classroom. BENEFITS OF BLOGGING IN THE ELEMENTARY CLASSROOM 3 What are the Benefits of Blogging in the Elementary Classroom? Technology can be used in the literacy classroom in a variety of ways to support and enhance instruction. Integrating technology into literacy instruction is becoming increasingly important as teachers are faced with creating a literacy environment that is appealing to a wide range of reading levels and learners, and the world is becoming one of technological literacies and global communication. Students of today are competent and fluent in the technologies that are available to them at home and outside of school, using them regularly in their personal lives. Technologies such as computers, iPods, and the many forums available on the Internet, such as instant messaging, emailing, and social networking websites, are all second nature to children today. It is necessary for teachers to find ways to bring these technologies into the classroom in order to close the gap that exists between home and school and engage students in ways that are familiar and comfortable for them. One of the ways to use technology in the classroom is through the use of blogging. BENEFITS OF BLOGGING IN THE ELEMENTARY CLASSROOM Theoretical Framework In order to determine how blogging in the elementary classroom can benefit students, it may be helpful to consider how literacy is acquired and language is learned. Sociocultural theory and New Literacy Studies are two theories that offer specific framework pertinent to the research that has been conducted on the topic. Sociocultural Theory Literacy is defined as a socially based practice, mediated by a person's culture BENEFITS OF BLOGGING IN THE ELEMENTARY CLASSROOM 5 communication and acts as a functional system within the social context and beyond. Children learn language in order to participate in the communicative world that surrounds them, but also learn language for social reasons as well. Humans are born with an innate desire to be social and share emotional bonds with others, and are able to facilitate this desire through the learning of language. As Barton and Hamilton (1998) suggest, literacy is a social activity that can be found in social interactions among people. Therefore, literacy practices involve all the socializing that is done each day, through both formal and informal interactions with others. This socializing begins in the home with a person's primary discourse, or communication that is culturally based and done with intimates, and is later extended to include secondary discourses, or ways of communicating with non-intimates beyond the home. Blogging is one way to communicate in a social context through the medium of technology. According to From this perspective, conceptualizing learning creates a shift from the traditional teacher-centered/student-centered classroom to one that is learning-centered. This means that in the classroom, according to For elementary students who are still developing their uses of language and forming their literacy skills, social interaction is key, as it broadens their perspectives and allows for the sharing and communication of ideas. New Literacy Studies BENEFITS OF BLOGGING IN THE ELEMENTARY CLASSROO
Pancreatic and multiorgan resection with inferior vena cava reconstruction for retroperitoneal leiomyosarcoma
Z-Pinch Pulsed Plasma Propulsion Technology Development
Fusion-based propulsion can enable fast interplanetary transportation. Magneto-inertial fusion (MIF) is an approach which has been shown to potentially lead to a low cost, small reactor for fusion break even. The Z-Pinch/dense plasma focus method is an MIF concept in which a column of gas is compressed to thermonuclear conditions by an axial current (I approximates 100 MA). Recent advancements in experiments and the theoretical understanding of this concept suggest favorable scaling of fusion power output yield as I(sup 4). This document presents a conceptual design of a Z-Pinch fusion propulsion system and a vehicle for human exploration. The purpose of this study is to apply Z-Pinch fusion principles to the design of a propulsion system for an interplanetary spacecraft. This study took four steps in service of that objective; these steps are identified below. 1. Z-Pinch Modeling and Analysis: There is a wealth of literature characterizing Z-Pinch physics and existing Z-Pinch physics models. In order to be useful in engineering analysis, simplified Z-Pinch fusion thermodynamic models are required to give propulsion engineers the quantity of plasma, plasma temperature, rate of expansion, etc. The study team developed these models in this study. 2. Propulsion Modeling and Analysis: While the Z-Pinch models characterize the fusion process itself, propulsion models calculate the parameters that characterize the propulsion system (thrust, specific impulse, etc.) The study team developed a Z-Pinch propulsion model and used it to determine the best values for pulse rate, amount of propellant per pulse, and mixture ratio of the D-T and liner materials as well as the resulting thrust and specific impulse of the system. 3. Mission Analysis: Several potential missions were studied. Trajectory analysis using data from the propulsion model was used to determine the duration of the propulsion burns, the amount of propellant expended to complete each mission considered. 4. Vehicle Design: To understand the applicability of Z-Pinch propulsion to interplanetary travel, it is necessary to design a concept vehicle that uses it -- the propulsion system significantly impacts the design of the electrical, thermal control, avionics and structural subsystems of a vehicle. The study team developed a conceptual design of an interplanetary vehicle that transports crew and cargo to Mars and back and can be reused for other missions. Several aspects of this vehicle are based on a previous crewed fusion vehicle study -- the Human Outer Planet Exploration (HOPE) Magnetized Target Fusion (MTF) vehicle. Portions of the vehicle design were used outright and others were modified from the MTF design in order to maintain comparability
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