Multipac, a multiple pool processor and computer for a spacecraft central data system

Spacecraft central data system computer used on deep space probe

Correlation of Student Participation in Practice Exams and Actual Exam Performance

Background: Practice exams are a type of formative feedback. These can be administered through learning management systems such as D2L and Canvas as low stakes assessment. This paper intends to show the relationship between students’ participation in online practice exams and their scores on the actual exams. Research Questions: Does participation in timed, online practice exams correlate with improved actual exam performance on similar questions? Does a correct answer in a timed, online practice exam correlate with obtaining the correct answer on the actual exam on a similar question? Does participation in timed, online practice exams correlate with improved overall course grades? Design/Method: The context of data collection includes mechanical engineering courses taught by the same instructor across thermodynamics, heat transfer, and dynamics. The practice exam questions and actual exam questions were designed from textbook homework questions, but with different surface characteristics. One question on the actual exam closely matched the single practice exam question provided. The students received an instant score from D2L or Canvas. This correlational study reviewed the factors of participation and score on practice exam, on the outcomes of score on actual exam and overall course grades. Results: Participation in practice exams correlates well with improved exam scores and improved overall course grades by about 1 letter grade for younger students. The score on the practice exam does not correlate with actual exam performance. Conclusions: Formative feedback is beneficial to younger students. There are many types of formative feedback. Engineering educators should adopt an appropriate form of formative feedback for younger students in exams

Exploration of aqueous interfaces and their effect on ion behavior

An in-depth understanding of a wide range of physical, chemical, atmospheric and biological processes can only be achieved after the structure and dynamics of interfaces and the interfacial behavior of aqueous species, such as ions, are thoroughly studied and understood. This dissertation describes computational studies conducted to gain a more comprehensive understanding of such interfaces and the behavior of ions in the bulk and interfacial regions of the (1) air/water interface, and (2) alkane/water interfaces. At the air/water interface the effect of counterion (sodium cations) charge and the influence of ion pairing on anion (chloride) propensity for the air/water interface of water was investigated. Higher counterion charge led to greater interfacial activity of the chloride anions and also caused stronger binding between the sodium and chloride ions. Shorter sodium-chloride interatomic distance also led to greater anion interfacial propensity while dampening the interaction strength between the counterion and anion had a small effect on propensity of the anions for the interface. Another phenomenon examined at the air/water interface was the effect of the halide ion in various sodium halide electrolyte solutions on the surface tension and surface excess while including electrostatic damping in the simulation model. Divalent strontium chloride was also examined in comparison to monovalent sodium chloride. Findings suggested that the smaller halide ions were found farthest from the air/water interface—in keeping with trends from previous studies—and resulted in the largest (most negative) surface excess, which would in turn cause the greatest increase in surface tension of water. Divalent strontium chloride had a more negative surface excess when compared to sodium chloride and the inclusion of electrostatic damping in the models reduced propensity of the ions for the interface and caused overall increase in surface excess. The alkane/water interface was investigated to determine the effect of changing the length of the alkyl chain on the water/alkane interfacial width. Two separate studies found that longer alkane chain length led to shorter alkane/water interfacial widths. A long term goal of this research is to catalog the behavior of ionic species at different interfaces. The distribution of sodium-halide ions was compared at the alkane/water and air/water interfaces. Sodium halide ions were found closer to the air/water interface than the alkane/water interface. In the future, similar studies will be carried out at the alcohol/water interface and the effects of the nature of the organic phase (alkane or alcohol with varied chain lengths, degrees of branching, and solubility in water) will be examined

MULTIPAC, a multiple pool processor and computer for a spacecraft central data system, phase 2 Final report

MULTIPAC, multiple pool processor and computer for deep space probe central data syste