3,570 research outputs found
Realization of a Laser Cooled Microwave Power Standard (conference digest)
We demonstrate the feasibility of a novel microwave power standard based on
the electromagnetic interaction with cold atoms. Under the effect of the
radiation, the internal state populations will undergo a Rabi oscillation. The
measurement of its frequency will allow the determination of the
electromagnetic field strength.Comment: 2 pages, 1 figur
Accuracy of an Atomic Microwave Power Standard
We have built an atomic microwave power standard based on the electromagnetic
interaction with laser-cooled atoms. The atoms traversed a waveguide
transmission line, and under the effect of the radiation, the internal state
populations underwent a Rabi flopping oscillation. Measurement of the
oscillation frequency allowed the determination of the incident microwave
power. As many of 60 oscillations were observed over a dynamic range of 20 dB
and the standard deviation of the measurements was about 0.02%. The measured
frequency was compared to a calculated one and an agreement of 1.3% with an
uncertainty of 5% (rectangular) was found.Comment: 5 figure
Data base architecture for instrument characteristics critical to spacecraft conceptual design
Spacecraft designs are driven by the payloads and mission requirements that they support. Many of the payload characteristics, such as mass, power requirements, communication requirements, moving parts, and so forth directly affect the choices for the spacecraft structural configuration and its subsystem design and component selection. The conceptual design process, which translates mission requirements into early spacecraft concepts, must be tolerant of frequent changes in the payload complement and resource requirements. A computer data base was designed and implemented for the purposes of containing the payload characteristics pertinent for spacecraft conceptual design, tracking the evolution of these payloads over time, and enabling the integration of the payload data with engineering analysis programs for improving the efficiency in producing spacecraft designs. In-house tools were used for constructing the data base and for performing the actual integration with an existing program for optimizing payload mass locations on the spacecraft
Student Perceptions: Teaching and Learning with Open Educational Resources
The purpose of this study was to analyze factors that may contribute to student perceptions of courses using Open Educational Resources (OER). Specifically, the 6 independent variables tested were the course discipline, age, gender, course delivery mode, enrollment status, and number of credit hours taken. The dependent variables were measured as mean scores of 6 OER perception dimensions: motivation to learn, quality of learning experience, value of OER, cognitive learning, affective learning, and course quality. A 27-item online survey was administered to gather data from students enrolled in a course that used OER in the fall semester, 2014. There was a 23% response rate with 80 completed surveys.
Independent-samples t tests were used to determine if significant differences existed between 5 of the 6 independent variables (the number of credit hours taken was tested using a different method) and each OER perception dimension mean. A Pearson product-moment correlation was used to determine whether there were significant relationships among the 6 dependent OER perception dimension means and the number of credit hours taken. The level of significance used was \u3c .05.
The findings of the independent-samples t tests revealed that there were no significant differences between the independent variables and the 6 OER perception dimension means. The motivation to learn perception mean was highest at 3.97 on a 5-point Likert-type scale; the value of OER had the lowest perception dimension mean of 3.37. The Pearson product-moment correlation determined that there was a significant weak negative relationship between the number of credit hours taken and the level of perceived cognitive learning dimension. All other correlations were found to have no significant relationships.
It can be concluded from the findings of the study that students are highly motivated to learn. From the perception rating of 3.37 for the value of OER, it can be concluded that student perceptions of the value of OER are slightly positive. It can also be concluded that as the number of credit hours in which a student is enrolled increases they have a lower perception of their level of cognitive learning
Student Perceptions: Teaching and Learning with Open Educational Resources
The purpose of this study was to analyze factors that may contribute to student perceptions of courses using Open Educational Resources (OER). Specifically, the 6 independent variables tested were the course discipline, age, gender, course delivery mode, enrollment status, and number of credit hours taken. The dependent variables were measured as mean scores of 6 OER perception dimensions: motivation to learn, quality of learning experience, value of OER, cognitive learning, affective learning, and course quality. A 27-item online survey was administered to gather data from students enrolled in a course that used OER in the fall semester, 2014. There was a 23% response rate with 80 completed surveys.
Independent-samples t tests were used to determine if significant differences existed between 5 of the 6 independent variables (the number of credit hours taken was tested using a different method) and each OER perception dimension mean. A Pearson product-moment correlation was used to determine whether there were significant relationships among the 6 dependent OER perception dimension means and the number of credit hours taken. The level of significance used was \u3c .05.
The findings of the independent-samples t tests revealed that there were no significant differences between the independent variables and the 6 OER perception dimension means. The motivation to learn perception mean was highest at 3.97 on a 5-point Likert-type scale; the value of OER had the lowest perception dimension mean of 3.37. The Pearson product-moment correlation determined that there was a significant weak negative relationship between the number of credit hours taken and the level of perceived cognitive learning dimension. All other correlations were found to have no significant relationships.
It can be concluded from the findings of the study that students are highly motivated to learn. From the perception rating of 3.37 for the value of OER, it can be concluded that student perceptions of the value of OER are slightly positive. It can also be concluded that as the number of credit hours in which a student is enrolled increases they have a lower perception of their level of cognitive learning
Clergy Retention in the Church of the Nazarene, the Role of the District Superintendent in Clergy Decision-Making Regarding Persistence in Active Vocational Ministry
The researcher theorized that collecting and analyzing data on variables associated with clergy attrition, particularly the relationship between pastor and district superintendent, would lead toward suggesting strategies for clergy retention that could be applied in the denominational judicatories of the USA and Canada region of the Church of the Nazarene. This study provided a fresh look at the pastor-superintendent relationship. The research demonstrated that superintendents are not and likely will not be highly engaged with pastors in the actual decision-making process regarding persistence in active vocational ministry. However, the study also revealed a strong desire among pastors for the involvement of district superintendents to deliver pastoral care during and after the emotional process of pastoral transition
Clergy Retention in the Church of the Nazarene, the Role of the District Superintendent in Clergy Decision-Making Regarding Persistence in Active Vocational Ministry
The researcher theorized that collecting and analyzing data on variables associated with clergy attrition, particularly the relationship between pastor and district superintendent, would lead toward suggesting strategies for clergy retention that could be applied in the denominational judicatories of the USA and Canada region of the Church of the Nazarene. This study provided a fresh look at the pastor-superintendent relationship. The research demonstrated that superintendents are not and likely will not be highly engaged with pastors in the actual decision-making process regarding persistence in active vocational ministry. However, the study also revealed a strong desire among pastors for the involvement of district superintendents to deliver pastoral care during and after the emotional process of pastoral transition
Effects of modifications to the space shuttle entry guidance and control systems
A nonlinear six degree of freedom entry simulation study was conducted to identify space shuttle guidance and control system software modifications which reduce the control system sensitivity to the guidance system sampling frequency. Several modifications which eliminated the control system sensitivity and associated control limit cycling were examined. The result of the modifications was a reduction in required reaction control system fuel
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